Water Assisted Injection Moulding: a Study on the Influence of Melt and Process Parameters on the Residual Wall Thickness and the Occurrence of Part Defects for Pa6.

KATHOLIEKE HOGESCHOOL LIMBURG Departement Industriele Wetenschappen en Technologie Water Assisted Injection Moulding: A Study on the Influence of Melt and Process Parameters on the Residual Wall Thickness and the Occurrence of Part Defects for PA6. Gielen Bjorn, Heynickx Lien, Van den Brink Dominique, Vandersteegen Jochen Water Assisted Injection Moulding: A Study on the Influence of Melt and Process Parameters on the Residual Wall Thickness and the Occurrence of Part Defects for PA6. Gielen Bjorn, Heynickx Lien, Van den Brink Dominique, Vandersteegen Jochen Received 7 March 2011 Abstract Although water assisted injection moulding is a relatively new and advanced technique to produce hollow parts, several problems which reduce the product quality can occur. Namely, water inclusions in the wall, severe fingering and double wall defects reduce the product part stiffness. This study investigated the effect of the process parameters water volume flow rate, water injection delay time and melt temperature on the part defects to obtain a better understanding of the formation of these part defects. The effect on the residual wall thickness and the weight of the products was also investigated. Three materials were used: two polyamides and one polypropylene as a reference. The experiments were carried out on an injection moulding machine equipped with a water-injection unit to produce hollow handles. The parts were weighed before and after drying, their wall thickness was measured and their percentage of defects was calculated in order to determine the influence of the processing parameters. IR images and pressure profiles ware also used to investigate possible detection methods for part defects. It was found that all the investigated parameters have a significant influence on the residual wall thickness and part defects. Their ‘ideal’ settings depend on the material and the desired properties since small wall thicknesses and few part defects do not always correspond. IR images can give an indication for the presence of defects, but the internal structure of the surface can not be examined using this technique. Key words: water assisted injection moulding, polyamide, processing parameters, residual wall thickness, fingering, double wall 1. 1. Introduction The development of the water assisted injection moulding (WAIM) technique has led to a breakthrough in the manufacturing of hollow or partly hollow plastic parts, which is not possible with the conventional injection moulding process [1] [2]. These hollow parts are characterised by the lighter weight of the products, relatively lower resin costs per part and less shrinkage and warpage compared to conventional moulded products [3]. Several techniques are available for the production of hollow parts. Two of the most important techniques for hollow parts are gas assisted injection moulding (GAIM) and water assisted injection moulding (WAIM). The principle of water assisted injection moulding is basically similar to gas assisted injection moulding, but the use of water has some interesting advantages over gas assisted injection moulding such as a shorter cycle time and an average smaller residual wall thickness of the products. This is due to the fact that the thermal conductivity and the heat capacity of water are respectively 40 and 4 times greater than those of gas [1], providing a better cooling of the part and therefore a faster production. Water assisted injection moulding is better to mould larger parts with a smaller residual wall thickness. Another advantage of water assisted injection moulding is the absence of the foaming phenomenon in the internal surface which can occur by using gas assisted injection moulding , since water does not dissolve or diffuse in the polymer melt during injection moulding. Disadvantages of water assisted injection moulding are part defects such as fingering and double wall arising in the internal surface. Also, the process is more complex so experience with conventional injection moulding is no guarantee for understanding water assisted injection moulding. The control f the process is much more critical, the design of the mould is more complicated and requires more knowledge of the dynamic interaction between the polymer and the filling water [4]. In addition, new water related processing parameters (water pressure, water injection delay time, water temperature, †¦ ) are involved and require proper adjustment [5]. The technology can be used to mould a large variety of polymers, includi ng glass fibre reinforced composites. Liu [6] reported the successful moulding of PP, PE, ABS and glass fibre filled polyamide 6 (PA6) composites with water assisted injection moulding. According to our investigation, few researchers have described the moulding of pure polyamide 6 with the water assisted injection moulding technique. By understanding the water assisted injection moulding process for this polymer, one is able to optimize the production and improve the product quality of PA6 parts. The water assisted injection moulding process can be applied in four variations [1] [6], which differ by the amount of injected polymer and introduction and evacuation of the water. In the short shot moulding process the cavity is first partially filled with polymer and in the next sequence, highly pressurised water is injected into the polymer core. The pressure is maintained during the cooling sequence to minimize the shrinkage and to further cool down the part. After cooling, the water is evacuated and the part is ejected. This technique is useful for thick parts, but the important limitation is the switchover mark on the surface [7]. This limitation can be eliminated by using the full shot moulding process in which the cavity is first completely filled with polymer. Next, the injection of water pushes the melt into a cavity positioned outside the cavity of the product. This overspill cavity arises by pulling back a core to enlarge the mould cavity for the overspill polymer which has to be removed from the product afterwards. Full shot moulding makes it possible to mould parts with a more uniform residual wall thickness through the end of the part in comparison to short shot moulded parts. Michaeli et al. [6] stated that the melt-push-back process is also capable to produce parts with a more uniform residual wall thickness distribution. In this process the water is injected in the reversed direction of the polymer injection and pushes the excess of melt back into the plasticizing unit. Finally, the core-pulling process uses a series of steel cores that are pulled back during water injection to increase the cavity volume and the product volume. This method produces parts with more uniform internal profiles in comparison to the former mentioned techniques. The investigated polymer, polyamide 6, is a semi-crystalline material that is classified as an engineering plastic. Beneficial properties of polyamide 6 over a wide range of temperatures and humidity are its high strength, high stiffness and toughness, good wear and abrasion resistance, low coefficient of friction and good chemical and electrical resistance [8], [9], [10], [11]. Further modification can be obtained by adding additives like fillers and plasticizers. Fillers achieve a better strength and stiffness, plasticizers cause higher toughness [12], [13]. Modification of the molecular weight has also a distinguishable influence on the polymer properties. The main drawback of polyamide 6 is the high moisture absorption affecting the rheological properties and deteriorating the processability. High moisture absorption causes part defects and results in a bad internal surface quality reducing the stiffness of the end product [14], [15], [16]. The absorbed water in the polymer has two important roles. Firstly, the water molecules act as plasticizers reducing the hydrogen bond interactions between the polyamide chains. Secondly, due to the hygroscopic nature of polyamide 6, the absorbed water influences the condensation reaction equilibrium depending on the initial moisture content [17], [18]. If the moisture content is less than prescribed thermodynamically, the reaction proceeds towards further condensation and an increase in molecular weight, increasing the viscosity exponentially. If the moisture content is higher than determined by the equilibrium, a hydrolysis reaction occurs. This causes a decrease in viscosity as well as degradation of the polymer. To properly process polyamide 6, the pellets are preferably dried to small moisture levels. Possible part defects that may occur in water assisted injection moulding are fingering and double wall. Liu and Lin [19], [20] investigated the problem of fingering in water assisted injection moulded composites. The fingering phenomenon comprises the non-uniformly penetration of water bubbles or steam into the polymer wall outside the designed water channels causing the formation of finger-shaped branches and small cavities in the polymer wall, which lead to a bad internal surface quality and a reduced part stiffness of the end product. Fingering depends on the dimension of the part: thick parts usually exhibit less fingering pattern than thin parts. Three factors might affect the formation of fingering. The first one is shrinkage of the polymer during cooling. During post-filling, the polymer undergoes volumetric shrinkage allowing water to penetrate into the parts. The more the polymer shrinks, the more water will penetrate into the part and causes fingering. However, this statement is in contradiction with the statement that thick parts exhibit less fingering, so research is necessary to investigate which conclusion is relevant for PA6. Shrinkage also depends on the crystallinity of the polymer. PA6 is a crystalline polymer and thus expected to show more shrinkage than an amorphous polymer. Also, water injection moulded parts show more fingering than gas injection moulded parts since water has a higher cooling capacity than gas and has a higher cooling rate of the polymer. This leads to a greater non-uniform temperature distribution in the polymer material which worsens the uniformity of water penetration inside the parts, resulting in fingering [20]. This is equal to the statement that more shrinkage leads to more fingering. The second factor is the viscosity of the polymer melt. During water injection, water follows the path with the least resistance. While the water enters into the mould cavity, it cools the polymer melt and increases the viscosity. It then becomes more difficult for the water to penetrate into the core of the parts. The third factor is the flow resistance in the channel and in the polymer. The higher the flow resistance in the channel and the lower the flow resistance in the polymer, the more water fingering will be induced. The researchers [19] concluded that water fingering worsens when a combination of a higher water pressure, a smaller melt short shot size and a shorter water injection delay time is used. Other parameters which need to be paid attention to are the temperatures of the melt, the mould and the water. Increasing these parameters decreases the cooling rate and the viscosity and results in more fingering because it is easier for water to penetrate in the part. Another possible part defect in water assisted injection moulding is double wall [22]. Double wall is the appearance of a second polymer wall inside the hollow product which deforms the wall significantly. During the water hold time water inclusions develop in the wall. The double wall is caused by the pressure drop after the water hold time. The water in the inclusions becomes steam and expands the internal material surface causing a second wall in the polymer. Two important parameters are responsible for the forming of double wall. The first parameter is the water hold time which should be minimized in order to eliminate double wall. Increasing the water hold time compensates the shrinkage in the wall but enlarge the water inclusions in the wall worsening the double wall. The second parameter is the volume flow rate. Increasing the volume flow rate causes more double wall because more water penetrates in the polymer forming water inclusions which expand into double walls after the water hold time. There is not much known about the phenomenon of double wall. A lot of investigators do not even make a difference between fingering and double wall and characterize it as the same part defect. Hollow parts are mainly characterized by their residual wall thickness that should be minimized in order to obtain a good product quality with minimal defects. A decline in wall thickness is mainly obtained by choosing water assisted injection moulding instead of gas assisted injection moulding [4]. However, Michaeli et al. [22] concluded that in some cases gas assisted injection moulding yields parts with a smaller residual wall thickness. Several process settings can be applied for water assisted injection moulding, each having an influence on the residual wall thickness. Huang and Deng [23] concluded that besides the short shot size there are two other main parameters affecting the residual wall thickness in polypropylene samples. The first parameter is the melt temperature. Increasing the melt temperature leads to reduction of the solidified layer thickness and thus to a decrease in wall thickness. The second parameter is the water injection delay time. When increasing the water injection delay time, the residual wall thickness exhibits an increment because the solidified layer of the melt becomes thicker. Liu and Wu [24] researched the effect of the injection pin on the residual wall thickness distribution. In their research they concluded that a pin consisting of a sintered porous surface can mould large parts with a more uniform residual wall thickness distribution. Application of this high flow rate pin could significantly improve the product quality in terms of smaller wall thickness. The non-uniformity of the residual wall thickness distribution usually occurring in curved product sections, was found to be less in water assisted injection moulded parts than in gas assisted injection moulded parts. Fluids try to follow the path with the least resistance; this is the shortest path. However, water has a higher mass inertion than gas and therefore gives a better concentricity of the residual wall thickness over a cross-section. The uniformity of the residual wall thickness could be improved by adopting different mould temperatures [25]. In order to mould PA6 parts with high product quality using WAIM, one has to apply the optimal settings to reduce the part defects (fingering and double wall) and decline the residual wall thickness. The water injection delay time influences fingering and the residual wall thickness. A shorter water injection delay time causes a smaller residual wall thickness but results in more fingering [19] [23]. The water volume flow rate is an important parameter on fingering, double wall and the residual wall thickness. A higher water volume flow rate gives a smaller residual wall thickness but more fingering and double wall [21]. The melt temperature has an influence on fingering and the residual wall thickness. Increasing the melt temperature leads to a smaller residual wall thickness but to more fingering [19] [20] [23]. Further experiments in this research focuses on the influence of the water injection delay time, the water volume flow rate and the melt temperature on the residual wall thickness and the occurrence of part defects for PA6, using a design of experiments. 2. Experimental procedure 2. 1 Materials To investigate the residual wall thickness and part defects like water inclusions, fingering and double wall of water assisted injection moulded products, two polyamides (PA F223-D and PA F130-E1 from DSM) and a polypropylene (PP 400-GA05 from Ineos) were used. The melting and crystallization temperature of the materials were measured with differential scanning calorimetry (TA Instruments 2920 CE). The viscosity was measured with a capillary rheometer (CEAST Smart Rheo 2000 twin bore). The complex viscosity, storage and loss modulus were measured with a parallel plates rheometer (AERES strain controlled rheometer). The measurements show that the zero-shear viscosity of the polypropylene is higher than those of the polyamides. PA F223-D has a higher zero-shear viscosity than PA F130-E1. This indicates that the molecular weight is higher for polypropylene than for PA F223-D and that PA F130-E1 has the lowest molecular weight. The decrease in viscosity at higher shear rates occurs at lower frequencies for polypropylene in comparison with the polyamides. This indicates a higher molecular weight distribution for polypropylene than polyamide. PA F223-D has a higher molecular weight distribution than PA F130-E1. . 2 Moulded parts The part that is moulded for this experiment is displayed in figure 1. It contains four curved sections varying in radius of curvature. The polymer and water enter the cavity at the bottom side. Water enters when a movable injector is pushed forward and a core at the end of the part is pulled allowing the polymer to be removed out of the inner core of the part. Figure 1: moul ded part containing four curved sections 2. 3 Equipment The injection moulding was executed with an Engel 80-ton injection moulding machine ES 330H/80V/80HL-2F. The dimensions of the machine are 4,80 m x 2,22m x 2m. The single screw diameter is 50 mm and the plastification unit can operate with a maximum injection rate of 152 cm? /s. A volume flow rate controlled water injection unit brings the water into the mould. It can operate with a maximum water volume flow rate of 30 l/min, delivered by a maximum pressure of 200 bar. During the tests a maximum pressure of 160 bar was applied. Three pressure sensors type Priamus are localized in the mould. An IR-camera type FLIR is used to observe the temperature distribution over the produced handles after moulding. The IR-images were used to compare with the internal section to discover the cause of part defects, because water in the product gives lower temperatures on the IR-image. The dried hollow polymer handles are sawed in lengthwise direction with a band saw. The band saw is type Metabo bas 260 swift. After sawing the hollow polymer handles, the internal section were scanned with a scanner type Cannon FG17500. A metric software 8. 01 plus was applied to analyze the surface quality of the polymer. With the aid of the software, the surface area of the wall and the part defects can be determined. . 4 Method DOE procedure The experiment investigated four processing parameters that were selected after a preliminary literature study, assuming these will have a significant influence on the residual wall thickness and part defects. These parameters are the water volume flow rate, water injection delay time and melt temperature. Using the design of experiments approach, each parameter was measured on a low and high setting; making this a 23 experiment. In addition three centre points were measured bringing the total number of experiments to 11 for each material. Response functions were constructed for residual wall thickness, weight and defects. The significance of each parameter was checked by comparing its effect to the deviation of the centre points, neglecting the parameter if its effect is smaller than the centre point deviation. Experimental procedure After steady state was reached, five shots were produced for each setting of water volume flow rate, water injection delay time, melt temperature. For each last shot of an experiment, a print screen of the pressure evolution and an IR-image was taken. During the process the following parameters were measured: * real injection time; * absolute shot volume; * real cushion; * flow number. After moulding, the parts were dried with compressed air to remove water of the inner- and outer surface of the product. Then the injection side of the product was removed and both halves were weighed. The sawed injection product was controlled on the presence of defects giving a first indication of the quality of the product. Afterwards the handle was dried in a furnace for 44 hours on 90  °C. After drying, the handles were weighed again obtaining the weight of the water inclusions in the product wall. Three representative handles were sawed in lengthwise direction and the breams were removed. The handles were scanned to determine the residual wall thickness and the percentages of defects like water inclusions, fingering and double wall. Table 1: Processing variables and settings used for the experiments | A| B| C| Process parameters| Water volume flow rate (l/min)| Water injection delay time (s)| Melt temperature ( °C)| -1| 10| 1,5| 240| 0| 20| 5| 260| 1| 30| 8,5| 280| A| B| C| Experiment| Water volume flow rate (l/min)| Water injection delay time (s)| Melt temperature ( °C)| 1| 20| 5| 260| 2| 10| 1,5| 240| 3| 30| 8,5| 240| 4| 30| 1,5| 240| 5| 10| 8,5| 240| 6| 20| 5| 260| 7| 30| 8,5| 280| 8| 10| 1,5| 280| 9| 10| 8,5| 280| 10| 30| 1,5| 280| 11| 20| 5| 260| Table 2:Experiment schedule for parameter settings The part defects are calculated as follows: The parameters whic h have an influence on the product quality are the water volume flow rate, the water injection delay time and the melt temperature. The tested parameter settings are presented in table 1. A code using -1 for low, 0 for center point and 1 for high setting is applied. The combination of parameter settings (Table 2) are determined using design of experiments. Using the design of experiments method makes is possible to obtain a better understanding of the formation of the defects and the influence of the processing parameters. Eventually a moulding window will e determined in which the defects are minimized. 2 Results and discussion 3. 1 Effect of water volume flow rate Figure 2 shows the effect of the water volume flow rate on the residual wall thickness and the product defects. Following paragraphs discuss these diagrams. Influence on the residual wall thickness and product weight Considering the residual wall thickness, polypropylene has a smaller residual wall thickness than the residual wall thickness of polyamide for all experiments. Polypropylene has a higher molecular mass, causing a wider water flow front. The higher molecular weight distribution (MWD) of PP causes a block velocity profile of the water resulting in a higher velocity on the polymer- water interface. The higher velocity causes a higher shearing and consequently a lower viscosity, resulting in a higher removal. This results both in a smaller residual wall thickness and a lower part weight. The density of polypropylene is lower compared to compared to the density of polyamide, which is also an explanation for the lower weight of product. Regarding the product weight and the residual wall thickness, the two polyamides do not differ much and correspond to each other. This is probably due to the small difference in molecular mass and molecular weight distribution. Figure 2: Effects of water volume flow rate on water inclusions, residual wall thickness, fingering and double wall The residual wall thickness of polyamide seems not to be significantly affected by the water volume flow rate. Polypropylene however, tends to increase in residual wall thickness by application of a lower water volume flow rate. These results correspond to the suggestion that a higher water volume flow rate gives a smaller residual wall thickness, as was found in preliminary literature study. In general a material with a high MWD, like PP, will be more influenced by the flow rate than other materials like polyamides. Influence on water inclusions In general the water inclusions tend to decline when the water flow rate increases. A higher flow rate provides more shearing, giving a lower viscosity. The water can easily remove the internal polymer and does not penetrate into the walls of the polymer. PP completely corresponds to this theory, but the polyamides show an irregularity during high flow rates. this can be explained by the strong variations in injection time and a chance in the water flow profile to a profile called recirculation flow. It pushes the water into the walls causing an increase in water inclusions. The strong variations that occur with PP are probably caused by its high MWD. This property also played an important role regarding the RWT. Influence on fingering Fingering is probably caused by differential shrinkage, making a material with a high degree of crystallization like polypropylene vulnerable to this defect. The defect diminishes at high flow rates where the wall thickness is smaller, making it more difficult for polypropylene to shrink and for fingering to occur. PA F130-E1 exhibits a low variation in fingering in comparison to the other materials. This material is not in its area of shear tinning when working with low flow rates, resulting in a constant viscosity and residual wall thickness. Because of this low variation in RWT and corresponding shrinkage with changing flow rate the effect of the flow rate will be very small. In general materials with a high MWD and MM like PP show more fingering than materials with low MWD and MM like PA F130E1. PA F223D will take a intermediate position taking into account that its centre point is not completely representative. This trend for fingering is visible for all parameters. Influence on double wall The influence of the flow rate shows an overall optimum profile. Low and high flow rates cause more double wall than an intermediate setting. A first theory relates this effect to the pressure inside the part. Low flow rates exert low pressure on the polymer melt and the polymer will not form a rigid layer, making it possible for the water to penetrate into the polymer walls. High flow rates cause high pressures inside the part forcing the water into the walls. The second theory is based on the tendency of water to follow the ath of least resistance and can only explain the effect with low flow rates. The low rate will cause almost no shear stress inside the polymer so it will not reach the shear tinning area. The polymer will not easily be pushed back by the water and the water will penetrate the walls where the resistance is much lower. The effect of the water volume flow rate on double wall is the same as for water inclusions, which is explained by the rel ation between water inclusions and double wall. Water inclusions can grow during the water hold time, collapsing into double walls in the product after pressure removal. The higher double wall defects for PAF130-E1 in comparison to PA F223-D are probably caused by the difference in molecular mass. PA F130-E1 has a lower molecular mass and thus a less viscous melt resulting in a more easily penetrable material. Another noticeable result is that of the investigated materials, PA F223-D shows high part defects but relatively the smallest double wall defects. PP, the material with the highest MM shows more double wall at high flow rates for which no explanation can be found. 3. 2 Effect of the water injection delay time Figure 3 shows the effect of the water injection delay time on the residual wall thickness and the product defects. Following paragraphs discuss these diagrams. Influence on the residual wall thickness and product weight A shorter water injection delay time causes a decline in the residual wall thickness and weight of product for polyamide and polypropylene, as was predicted by literature. When the water injection delay time is short, the polymer is still hot and has a low viscosity, giving the water the opportunity to hollow out the polymer more. A higher water injection delay time causes a higher residual wall thickness and weight of product because the melt viscosity increases. The residual wall thickness is higher for polyamide than for polypropylene, for the same reasons as discussed under the previous paragraph. Influence on water inclusions An increase in delay time is accompanied by an increase in viscosity that makes it more difficult for the water to penetrate into the walls. However, if the viscosity is too high, the water can also be forced into the walls, which explains the slight increase in water inclusions for PP 400-GA05 and PA F130-E1. Figure 3: Effects of the water injection delay time on water inclusions, residual wall thickness, fingering and double wall The strong decrease in water inclusions that occurs with polypropylene is caused by the high heat capacity of this material making it cool down faster than the polyamides and increasing its viscosity faster. PA F130-E1 shows less defects in comparison with PA F223-D, probably caused by its strong temperature related viscosity. During the delay time the viscosity strongly increases, making it more difficult for the water to penetrate. Influence on fingering Increasing the delay time increases the residual wall thickness and should result in a higher chance of fingering. In general this trend can be observed from the diagrams. More fingering occurs within PP 400 GA05 caused by its higher degree of crystallization. Furthermore, this polymer is processed at much higher temperatures than its melting point, leading to further shrinkage and corresponding fingering. The presence of defects during processing with long delay times is caused by a greater residual wall thickness, which leads to more differential shrinkage. Processing with short delay times increases the presence even further, but no plausible statement can explain this. Therefore further research will be necessary. The results for the centre point of PA F223-D are probably not representative, since it is based on a single experiment of three shots. Influence on double wall The water injection delay time shows an overall optimum profile, which can be related to the shift of the rigidity in time, caused by the temperature drop over time. Production with a short delay time will push water inside the low viscosity polymer which makes it easy for the water to penetrate. Increasing the delay time also increases the viscosity and thus the rigidity of the polymer making it harder to penetrate the walls. However, if the viscosity is too high, the water will also be forced into the walls. PA F130-E1 shows more double wall because its viscosity is highly temperature related. Longer delay times will lead to larger temperature drops and a corresponding increase in viscosity. 3. 3 Effect of the melt temperature Figure 4 shows the effect of the melt temperature on the residual wall thickness and the product defects. Following paragraphs discuss these diagrams. Influence on the residual wall thickness and weight of product Considering the residual wall thickness, polypropylene has a lower residual wall thickness and weight of product compared with polyamide for all experiments. This might be due to the higher molecular weight and the higher molecular weight distribution of polypropylene. The higher molecular weight distribution shows a square blocked velocity profile causing a higher velocity on the wall and a higher shearing. This results in a lower viscosity and therefore more removal of the polymer decreasing the residual wall thickness and weight of product. PA F130-E1 and PA F223-D are quite similar and do not differ much in residual wall thickness and weight of product. Increasing the melt temperature leads to a smaller residual wall thickness as was suggested by literature, because a higher melt temperature makes the polymer less viscous so more polymer can be removed by the water. The residual wall thickness of PP decreases from 240 °C to 260 °C but increases to 280 °C. The increase of the melt temperature is difficult to explain and is possible a unreliable point. In fact, also for polypropylene a decreasing tendency is remarkable. Influence on water inclusions There is a trend towards higher water inclusions when a higher melt temperature is applied. This parameter thus shows the opposite effect of the delay time. PA F130-E1 differs from the other materials, probably due to the strong variations in injection time during production. Furthermore this polymer shows a lot of internal heating (viscous heating) when Figure 4: Effects of the melt temperature time on water inclusions, residual wall thickness, fingering and double wall high pressure is exerted, leading to a drop in viscosity. This effect usually appears in combination with low melt temperatures where the polymer has a lot of pressure to bear. So low temperatures will lead to viscous heating and therefore to high intern temperatures. The water can then easily enter the walls of the polymer due to the lower vicosity. Influence on fingering When processing the material at low temperatures, the material will have to shrink less and thus less fingering will occur. This trend is clearly visible for the polyamides, taken into account that the centre point of PA F223-D is not representative. In fact, the effects should show an opposite effect from the delay time, but this is not clearly noticeable. Further research will be necessary to explain these irregularities. Influence on double wall A higher melt temperature causes an overall increase in double wall defects for all three materials. This effect is related to the viscosity of the polymer which varies with temperature. High temperatures will lead to a decrease in viscosity making the polymer more penetrable for water. Another theory is based on the water flow profile inside the polymer. Higher temperatures usually correspond to smaller residual wall thicknesses changing the flow profile into a recirculation flow where water will be pulled into the walls. 3. 4 Comparison results of response functions and graphical tendencies Table 3 gives an overview of the best parameter settings to reduce each part defect and the total defects for each material, comparing the results of a response function (before /) and the graphics in figure 1/2/3 (after /). The response functions were constructed using the design of experiments method. Regarding the defects, only one response function was made which ncludes both fingering and double wall. Ideal settings according to response functions Using the response functions several conclusions can be made for the ideal settings of the parameters. A high water injection delay time creates less water inclusions in both polyamides. In addition, the polyamides show the same optimal settings of all parameters for the residual wall thickness. A low water volume flow rate is beneficial for the reduction of the residual wall thickness, fingering and double wall. Other settings conflict to give minimal part defects in polyamide. In general, PA F223-D has minimal part defects for a low water volume flow rate, a high water injection delay time, and a low melt temperature. PA F130-E1 requires a low water volume flow rate as well, but a low water injection delay time and a high melt temperature. The optimal settings for the minimal percentage water inclusions, fingering and double wall are highly contradictory for polyamide and polypropylene. PP 400-GA05 requires a high water volume flow rate for a smaller residual wall thickness but the other parameters have the same optimal settings for the residual wall thickness as polyamide 6. The water volume flow rate and the water injection delay time do not influence fingering and double wall significantly, so no conclusions can be made for these settings to obtain minimal fingering and double wall. If also the water inclusions and the residual wall thickness are taken into account, PP400-GA05 shows minimal part defects for a high water volume flow rate, a low water injection delay time and a low melt temperature. There can be concluded that for all three materials the best parameter settings for residual wall thickness, fingering and double wall are not the same. Since other effects may probably have an influence on the materials, further investigation will be necessary. Ideal settings according to previous diagrams The following best parameter setting are based on the previous graphics. Regarding the residual wall thickness, the best parameters for PP and PA F130D are an intermediate water flow rate, a low water injection delay time and a high melt temperature. For PA 223D, a low water flow rate is required and the other parameters are the same. For fingering, a high water volume rate, an intermediate water injection delay time and melt temperature give the best results for PP. PA F223D gives the best results for a low water volume flow rate and water injection delay time and an intermediate melt temperature. PA F130E1 in contrary, the best parameters setting are a high water volume flow rate and a low water injection delay time and melt temperature. The parameters setting are different for the three materials and show a lot of irregularities. Considering double wall, the best parameter settings are a low water flow rate, water injection delay time and melt temperature. For both polyamides the best parameter setting are equal, an intermediate water flow rate, delay time and melt temperature. For the water inclusions, the best results were observed for a high water volume rate and an intermediate water delay time and melt temperature. PA F223D shows less water inclusions when an intermediate flow rate, a low delay time and in intermediate melt temperature is used. PA F130E1 in contrary gives the best results for a intermediate flow rate and delay time and a low melt temperature. Ideal settings for PA F223-D| | Optimal setting| Response factor| Target figure| Water volume flow rate| Water injection delay time| Melt temperature| Water inclusions| Low| High/High| High/High| Low/Low| Residual wall thickness| Low| Low/High| Low/Low| High/High| Fingering and double wall| Low| Low/High| High/Low| Low/Low| Total| | Low/High| High/Low| Low/Low| Table 3: Overview of ideal settings for the materials for each part defect Ideal settings for PA F130-E1| | Optimal setting| Response factor| Target figure| Water volume flow rate| Water injection delay time| Melt temperature| Water inclusions| Low| Low/High| High/High| High/Low| Residual wall thickness| Low| Low/High| Low/Low| High/High| Fingering and double wall| Low| Low/High| Low/Low| Low/Low| Total| | Low/High| Low/Low| High/Low| Ideal settings for PP 400-GA05| | Optimal setting| Response factor| Target figure| Water volume flow rate| Water injection delay time| Melt temperature| Water inclusions| Low| High/High| Low/High| High/Low| Residual wall thickness| Low| High/High| Low/Low| Low/High| Fingering and double wall| Low| -/High| -/Low| Low/Low| Total| | High/High| Low/Low| Low/Low| Once again, here can be concluded that the best parameter settings for residual wall thickness, fingering and double wall are not the same. Since other effects may probably have an influence on the materials, further investigation is necessary. . 5 Detection of part defects 3. 5. 1 IR-images IR images were tested if they can be used to obtain an indication of the quality of the product. This could be an important tool during production as it can deliver information about the internal structure without damaging the part. It was found that a uniform heat distribution in the part usually corresponds to few defects in the walls. The polymer equally shrinks and cools, causing no stress in the walls which could lead to defects. Figure 5 shows the section and an infrared image of a hollow part from PP 400-GA05 without defects. The corresponding IR picture shows no significant Figure 6: Scan and IR image of PP 400-GA05 product with defects irregularities in the heat distribution. The areas where the part has a higher or lower Figure 5: Scan and IR image of PP 400-GA05 product without defects temperature than the bulk are caused by respectively larger and smaller residual wall thicknesses. Small defects like fingering can occur where colder areas are completely surrounded by larger hot material making it isolated cold regions. If the cold area is gradually spread throughout the part and is therefore no isolated region, fingering is often not present. The isolated colder regions are most likely filled with water which provides more efficient cooling than the rest of the part, resulting in uneven shrinkage and corresponding fingering cavities. Large defects like double wall are often present where a relative large cold area spreads throughout the complete section and is surrounded by hot material. These defects are also likely to occur in regions with higher temperature than the rest of the part. However, the latter can also correspond with a larger residual wall thickness and is thus not conclusive for the presence of double wall defects. Figure 6 shows a part with double wall defects and the corresponding infrared image where the isolated hot (white) and cold areas (yellow) are indicated. The texture of the internal surface can not be judged with an infrared image. PA F130-E1 tends to show a rougher surface in regions with a much lower temperature, but not all parts share this conclusion. Within the other materials a rough surface does not corresponds with lower temperature areas thus the infrared does not delivers clear information about this property. 3. 5. 2 Pressure and injection rate profiles The pressure profiles and the injection rate during the injection of the melt can be used to declare some of the defects shown in the different polymer samples. The injection rate was set on 45 mm/sec and the maximum feasible pressure of the WAIM equipment was 160 bar. For the polyamides, this maximum pressure was exceeded in some cases during filling of the mould. This caused a temporary reduction of the injection rate and possibly some of the part defects of polyamide. Polypropylene does not show this trend because it has a lower flow number than PA. Figure 7 shows an example of this phenomenon in PA F223-D. In general it can be concluded that when the temperature increases the measured pressure and the flow number decrease. This reduction in pressure can be explained by the fact that the viscosity of the material will be lower at a higher temperature, so the polymer can flow easier and less pressure has to be applied. However it is not guaranteed that an irregularity in the injection profile of the polymer results in problems during water injection. This experiment was to limited to make clear conclusions about this effect. Figure 7: Pressure and injection rate profile for PA F223-D (green=pressure, blue=injection rate) 4. Conclusions 4. 1 General This report has studied the influence of melt and processing parameters on the residual wall thickness and the occurrence of part defects of PA6 parts produced with water assisted injection moulding. The study examined two polyamides (PA F223D, PA F130E1) and polypropylene 400 GA05 that was used as a reference material. According to a design of experiments, the water volume flow rate, the water injection delay time and the melt temperature are the investigated processing parameters. The water volume flow rate settings are 10, 20 and 30 l/min, the injection delay time settings are 1,5s, 5s and 8,5s and the melt temperature settings are 240 °C, 260 °C and 280 °C. It was found that the residual wall thickness showed a large distribution for all three materials, even for shots from a single experiment and therefore an extra analysis was made on the weight of the products. The product weight can give an indication for the wall thickness as a low weight usually corresponds to small thicknesses. Based on this theory it was found that the water volume flow rate has little influence on the weight and wall thickness. A larger delay time increases the viscosity of the polymer and leads to higher weight and a larger wall thickness. The melt temperature has the opposite effect, decreasing the viscosity at higher temperatures and therefore decreasing the wall thickness and weight. PP has a lower weight comparing with the two polyamides. This can be explained that PP has a higher molecular weight and molecular weight distribution. A higher molecular weight gives a parabolic velocity profile and a higher molecular weight distribution shows a square blocked velocity profile causing a higher velocity located on the wall. The higher velocity causes a higher shearing giving a lower viscosity. This results in more removal of the polymer and the residual wall thickness decreases. In fact, a lower residual wall thickness exhibits a lower weight of product. The water inclusions for the three materials tend to decline when the water flow rate increases although PP shows some irregularities. The delay time has an overall optimum profile. Intermediate settings exhibit less inclusions in comparison to other settings. The melt temperature has the opposite effect of the delay time so more water inclusions occur when higher temperatures are applied. Other defects like fingering and double wall are also influenced by the investigated processing parameters. The water flow rate shows an optimum profile for double wall, so an intermediate setting will yield the best results. For fingering the three materials all act in a different way to the flow rate. An optimum profile also occurs for double wall when the delay time is investigated. In general, fingering increases when the delay time increases, but the materials show a lot of irregularities. An increase in melt temperature causes an overall increase of fingering and double wall. Comparing PA6 and PP, PP shows an overall smaller residual wall thickness than PA6, but on average the same percentage of part defects. This means that a reduction in residual wall thickness does not influence the product quality for part defects positively. When comparing the different polyamides 6, the investigated low viscosity polyamide 6 PA F223-D show less water inclusions and fingering but more double wall than the medium viscosity polyamide 6 PA F130-D. The best choice for a polyamide depends on the relative importance of the negative influence of each part defect on the product quality. This is discussed in detail in the next paragraph. To get an indication of the quality of the product IR images can be used. It was found that a uniform heat distribution corresponds to few defects and irregularities point to the presence of defects like fingering or double wall. The internal texture of the surface can not be examined with IR. This study concludes that the investigated parameters have a significant influence on the presence of part defects and on the residual wall thickness. However, there are still irregularities in the results of the fingering phenomenon that can not be explained yet with the current knowledge of the water assisted injection moulding process. Therefore further analysis will be necessary to examine this part defect. Further research can be done by expanding the design of experiments and by producing more shots for each experiment. Producing more than three shots of each experiment should give more corresponding results, because the standard deviation of three shots is usually high. 4. 2 Selection of the material for WAIM Three materials were used in this experiment namely PA F223D, PA F130E1 and PP as reference. The residual wall thickness, weight of product, water inclusions and part defects like fingering and double wall must be compared with each other to choose the best material. This by varying the selected parameters like water volume rate, water injection delay time and melt temperature. PP has in general the lowest weight of product and residual wall thickness for the three investigated parameters: water volume rate, water injection delay time and melt temperature. As a result of a smaller residual wall thickness, PP has the lowest weight of product. Considering the water inclusions a decreasing tendency is obtained when a higher water volume flow rate and water injection delay time is used. There is a trend toward higher water inclusions when higher melt temperature are applied. Regarding to fingering and double wall, an opposite effect is noticeable. Increasing the water volume rate and water injection delay time gives a decreasing fingering tendency but more double wall effects. For a higher melt temperature, an increase of fingering and double wall is observed. PA F130E1 and PA F223D are quiet similar to each other in weight of product and residual wall thickness. For the weight of product PA F130E1 and PA F223D correspond to each other and for the residual wall thickness they do not differ much for all three investigated parameters. Regarding the water inclusions, both polyamides decline when water the flow rate increases. The highest flow rate provides more shearing and therefore a lower viscosity resulting in more water inclusions. Increasing the water injection delay time leads to lower water inclusions because the viscosity increases which makes it more difficult for water to penetrate into the walls. When higher melt temperatures are applied, results in a trend towards higher water inclusions because of the lower viscosity. In general, PA F223D shows more water inclusions comparing with PA F130E1 for the water volume flow rate, water injection delay time and the melt temperature. Considering fingering and double wall, different results were observed for the two polyamides. In general it is remarkable that PA F223D shows more fingering then PA F130E1 while PA F130E1 gives more double wall then PA F223D and this for the three investigated parameters. For the water volume flow rate, the polyamides act in different ways towards fingering. Although, for double wall the flow rate shows an optimum for the polyamides so an intermediate setting gives the best results. When the water injection delay time increases there is also an increasing tendency of fingering observed but the materials show a lot of irregularities. Increasing the melt temperature gives an increase of fingering and double wall as well. In this investigation can be concluded that both polyamides have their advantages and disadvantages. A selection of the best polyamide depends on which effect is undesirable. The residual wall thickness are the same for the two polyamides. PA F223D shows more water inclusions and fingering for all investigated parameters. However, PA F223D shows less double wall and therefore the best results. PA F130E1 in contrary gives more double wall effects but less fingering and water inclusions. In fact, PA F223D is preferred when double wall must be reduced and PA F130E1 is preferred when fingering and water inclusions must be reduced. Further investigation is necessary on another type of polyamide which improves the product quality using WAIM. References [1] Knights, M. (2002). Water Injection Molding Makes Hollow Parts Faster, Lighter. Plastics Technology, pp. 42-47, 62-63. 2] Liu, S. -J. , & Lin, M. -J. , & Wu, Y. -C. (2007). An experimental study of the water-assisted injection molding of glass fiber filled poly- butylene-terephthalate (PBT) composites. Composites Science and Technology, pp. 1415- 1424. [3] Liu, S. -J. , & Hsieh, M. -H. (2007). Residual Wall Thickness Distribution at the Transition and Curve Sections of Wat er-assisted Injection Molded Tubes. International Polymer Processing, pp. 82-89. [4] Liu, S. -J. , & Chen, Y. -S. (2003). Water- Assisted Injection Molding of Thermoplastic Materials: Effects of Processing Parameters. Polymer Engineering and Science, pp. 806- 1817. [5] Liu, S. -J. , & Wu, Y. -C. (2007). Dynamic visualization of cavity-filling process in fluid- assisted injection molding-gas versus water. Polymer Testing, pp. 232-242. [6] Liu, S. -J. (2009). Water Assisted Injection Molding: A Review. 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Polymer, pp. 9923- 940. [13] Uribe-Arocha, P. , Mehler, C. , Puskas, J. E. & Alstadt, V. (2003). Effect of Sample Thickness on the Mechanical Properties of Injection Molded Polyamide-6 and Polyamide- 6 Clay Nanocomposites. Polymer 44, pp. 2441-2446. [14] Steeman, P. & Nijenhuis, A. (2010). The Effect of Random Branching on the Balance between Flow and M echanical Properties of Polyamide-6. Polymer 51, pp. 2700-2707. [15] Incarnato, L. , Scarfato, P. , Scatteia, L. & Acierno, D. (2004). Rheological Behavior of New Melt Compounded Copolyamide Nanocomposites. Polymer 45, pp. 3487-3496. 16] Meng, Y. Z. & Tjong, S. C. (1996). Rheology and morphology of compatibilized polyamide 6 blends containing liquid crystalline copolyesters. Polymer 39 No. 1, pp. 99-107. [17] Acierna, S. , & Van Puyvelde, P. (2005). Rheological Behavior of Polyamide 11 with Varying initial Moisture Content. Journal of Applied Polymer Science, pp. 666-670. [18] Chow, W. , Bakar, A. , & Ishak, Z. (2005). Water Absorption and Hygrothermal Aging Study on Organomontmirillonite Reinforced Polyamide6/polypropylene Nanocomposites. Journal of Applied Polymer Science, pp. 780- 790. [19] Liu, S. -J. , & Lin, S. -P. (2005,april). Study of Fingering’ in Water-assisted Injection Molded Composites. Polymer Rheology and Processing lab. [20] Lin, K. -Y. , & Liu, S. -J. (2009) . The Influence of Processing Parameters on Fingering Formation in Fluid Assisted Injection Molded Disks. Polymer Engineering and Science, pp. 2257-2263. [21] Walter Michaeli, E. H. (2010). ‘Perspective Kunststofftechnik berichte 2010’ IKV- Kolloquium Aachen 2010 pp. 19-21 (Analyse der Fehlerentstehungs-mechanismen). [22] Michaeli, W. , & Lettowsky, C. , & Groenlund, O. (2005). Understanding Residual Wall Thickness. Kunststoffeplast Europe 95, pp. 87-91. [23] Huang, H-X. , & Zhou, R-H. 2009). Preliminary investigation on morphology in water-assisted injection molded polymer blends. Polymer testing, pp. 235-244 [24] Liu, S. -J. , & Wu, Y. -C. (2006). A Novel High Flow Rate Pin for Water-assisted Injection Molding of Plastic Parts with a More Uniform Residual Wall Thickness Distribution. International Polymer Processing, pp. 436-439. [25] Lin, K. -Y. , Chang, F. -A. & Liu, S. -J. (2009). Using Differential Mold Temperatures to improve the Residual Wall Thickness Uniformit y Around Curved Sections of Fluid Assisted Injection Molded Tubes. International Communications in Heat and Mass Transfer 36, pp. 491-497.

Pros and Cons of Inclusive Education Essay

Pros and Cons of Inclusion in a general education classroom Inclusion in a general classroom is one of the largest controversies that schools face today. Most administrators, parents and teachers question the likely academic impacts associated with the placement of students with special needs into general educational classrooms. Inclusion is the educational approach that requires students with disabilities to learn together with non-disabled students. Rather than the segregation of students based on their physical abilities and disabilities, inclusion dictates that each and every student is a learner who should benefit from a challenging, meaningful and appropriate curriculum. Despite the fact that inclusion had its focus on disabled students, it has been designed to accommodate diverse strengths, experiences, and challenges of all students. Research suggests that inclusion is beneficial for the students’ academic progress; increases social development and helps increase self- esteem of the students. The following annotations throw more light on the concept of inclusion in general educational classrooms. Caralee Adam’s â€Å"The Challenges of Inclusion†. She highlights that most experts and teachers support the objectives of inclusion. However, the main idea she addresses is responsible inclusion. In other words, the teachers and the experts are calling for modifications in the inclusion models such that some scenarios like violent or aggressive kids can be handled effectively.She presents relevant and sufficient evidence in the name of Bill Hutchison, a violent eleven-year old with Down syndrome. This source helps to highlight the key leverage points for effective inclusion. The reputable publication is obtained from a credible source and is sponsored by Scholastic Administrator. Adam owns a bachelor’s degree in Journalism and Mass Communication from Iowa State University and a master’s degree in political science from the University of Orleans. She i s a trusted and renowned freelance writer on topics such as health, personal finance, parenting education, et al. Barker’s Does Inclusion Help? This annotation addresses a range of questions through research but chiefly, the impact of inclusion on the entire body of students. On the same note, Barker is interested to know the attitude of disabled students towards learning. He provides sound evidence through a descriptive research. In line with the thesis statement, the publication helps us recognize the effect of inclusion on the students and their  attitudes too. Through this research we can answer whether inclusion really helps or not. This is a trusted reputable source too sponsored by the National Association of Special Education Teachers. Benefits of Inclusive Education. In contrast to most articles that focus on the benefits of inclusion to only disabled students, this annotation highlights what both disabled and non-disabled students benefit with by learning together in one classroom. For instance, disabled students are rewarded with friendships and social relations, greater access to general curriculum, greater opportunities to interact et al. The benefits to non-disabled students include: meaningful friendships, helps them respect all people, ability to understand and accept diversity et al. This source-Kids Together , Inc- is reliable as it is a nonprofit organization that provides resources and information for adults and children with disabilities. This agrees with our thesis statement on the benefits of inclusion in a general educational classroom. However, this source does not provide us with significant evidence through real-life examples or by research whether the specified benefits are actually realized. The next annotation is titled, â€Å"Cons of Inclusion†. This annotation highlights some of the arguments as well as the major concerns against inclusion. In particular, it states the disadvantages of inclusion in a general educational classroom.For instance, inclusion consumes a lot of the teachers time while some teachers lack training and classroom management is a difficult task. In spite of the fact that we do not know the exact author of this article, the source is reputable, credible and the evidence it provides in one 10-year-old Ryan with learning disabilities is magnificent. This evidence is collected through observational fieldwork and hence it is significant. It is too in line with the purpose of the essay though it features it is a one-sided scenario. In other words, it addresses the cons of inclusion rather than both the pros and cons of inclusion. Another interesting annotation on inclusive education is, â€Å"History of Inclusion† by Stephanie Torreno. A century ago, most disabled students were uneducated but today they do learn beside non-disabled students, thanks to the Rehabilitation Act of 1973 and the subsequent 1986 and 1992 amendments. Consequently, educational and employment rights for disabled persons were  guaranteed by federal funded institutions. Most importantly, it brings to light a series of legislation s that have been adopted in the context of inclusive education and regarding employment of disabled persons. Understanding the history of inclusion helps us to evaluate how beneficial inclusion has been hence agreeing with our thesis statement about benefits of inclusion. This source is a reliable one as the author herself is disabled. And therefore we do believe in her interest regarding government laws on education and employment of disabled people. She was born in Niskayuna , USA and in spite of her physical disability, she owns a bachelor’s of Arts degree in Psychology and technical writing. Inclusion by CollenTomko is also another annotation on inclusive education that we focus on. According to Collen, the inclusion objective is attained when children fully participate in class activities as members with all the services and support that they require. Regardless of the class the students learn in, the developed plan should be around their individual needs. She asserts that, children do not necessarily have to become normal in order to effectively contribute to the world. This and in accordance with the context thesis statement on benefits of inclusion, we are able to understand the main goal of inclusion. Kids Together Organization is an already trusted source and Collen Tomko who holds her Bachelors degree from Pennsylvania State University is the president and co-founder of this non-profit organization providing more reason to believe her. Next is, Inclusive Learning Environment for Students with Special Needs. Dee Dickson is the founder of New Horizons for Learning (NHLF), a resource for comprehending learning. The network was used to convey new information to teachers. NHFL guides teachers on fresh effective teaching and learning practices so as to see the whole process of inclusion a success. For us to realize the full benefits of inclusion in general education classrooms, NHFL therefore provides teachers with updated information and resources to effectively educate inclusive classrooms. On Dee Dickson, she has taught each and every level right from elementary schools up to university. In this regard, her experience in teaching diverse students is profound and therefore provides reason to believe in her articles. Besides, New Horizons For Learning is an established, reputable and among the leading learning web sources that identify and communicate successful strategies to adopt in educational  practice. Another Inclusive education related annotation is SEDL-Issues About Change: Inclusion: The Pros and Cons. The article addresses the advantages and disadvantages of inclusion in general educational classrooms. Many questions are asked in this context, namely: what inclusion actually means; how inclusion looks like; comparison and contrast between full inclusion and mainstreaming, et al. It investigates a range of issues that surround inclusion. But chiefly, and in with reference to the thesis statement, the article highlights the pros and cons of this practice. The provision of a historical synopsis about special education development ensures that we could trust this source even though the author is not stated. The paper also provides us with implications for policy makers and educational practitioners. The other paper on the same topic is â€Å"Special Education Inclusion†. This article highlights the confusion the concept of inclusion causes to parents and educators. They do not know whether inclusion is required legally or not and also what is better for their children. The article therefore is about what institutions must do so as to maximally meet the needs of all disabled children. In other words, before we realize the benefits of inclusion, we must answer the question on what must be done and how it should be done. All stakeholders must be involved research, discussions and examination of the entire inclusive educational program for effective or fruitful planning. The annotation is sponsored by a credible source-The Winsconsin Education Association Council (WEAC) which is a representation of education of public employees. Special-needs Education: Does Mainstream Inclusion work? The article is about developing a closer relationship between mainstream schools and special education schools. Yes, ideal inclusion is very expensive but having special schools separately is expensive as well. The respondents featured in this article believe that the curriculum for disabled students needs to be totally different from that of non-disabled students but it is so heartbreaking when students are isolated and stuck in classrooms lacking specialized help. Hence advocates co-location so as to ensure that these students do not suffer. Thus, inclusion in general educational classrooms becomes the only choice. The source is from a UK-based newspaper-The Independent Saturday and can thus be trusted. Starr, Linda. â€Å"Inclusion: Has It Gone Too Far?† One of the advantages of inclusion is reduction of educational fragmentation and  provides an environment in which all the available educational resources are used to improve the performance of each and every child. Inclusive education can be designed for the benefit of both students and teachers through ensuring that all the fisca l and human resources are utilized for the entire body of students. Reduction in educational fragmentation is main benefit of inclusion and therefore in line with the thesis statement about the benefits of inclusion in general educational classrooms.

Dunkin’ Donuts: Betting Dollars on Donuts

Once a niche company operating in the northeast, Dunkin' Donuts is opening hundreds of stores and entering new markets. At the same time, the java giant is broadly expanding both its food and coffee menus to ride the trends, appealing to a new generation of customers. But is the rest of America ready for Dunkin' Donuts? Can the company keep up with its own rapid growth? Serving the Caffeinated Masses There's a lot more to a coffee shop. Some 400 billion cups of coffee are consumed every year, making it the most popular beverage globally. Estimates Indicate that more than 100 million Americans drink a total of 350 million cups of coffee a day. But Dunkin' Donuts does, and it's betting dollars to donuts that consumers nationwide will embrace its reputation for value, simplicity, and a superior Boston Kreme donut. Winning New Customers Most of America has had an occasional relationship with the Dunkin' Donuts brand through its almost 5,800 domestic outlets, which have their densest cluster in the northeast and a growing presence in the rest of the country. But the brand has also managed to carve out an International niche, not only in expected markets such as Canada and Brazil, but also in some unexpected ones, including Qatar, South Korea, Pakistan, and the Philippines. The company had 7,306 Dunkin’ Donuts stores in the U. S. at the end of 2012 and plans to double the number in the next 20 years. In 2013, it will add another 330-360 restaurants across the country. In order to accelerate store openings, Dunkin’ is offering incentives to franchisees such as reduced royalty payments during the initial phase. Trefis expects the company to add around 300 new Dunkin’ Donuts stores in the U. S. on average for the next several years. Since most of Dun kin’ Brands restaurants are franchised, the capital requirements to open new restaurants are lower which ensure that the expansion plans do not cause a strain on the company’s fiscal situation. What Would Consumers Think? None of Dun kin Donuts' moves makes much difference unless consumers buy into the notion that the company has the culinary imperative to sell suggests. At one point of time Dunkin Donuts decided to add on to its product line by incorporating the breakfast menu. There was a doubt in the minds of people handling strategic marketing that even when consumer see the line of products expand into what was once solely the realm of the company's competitors, they may be unconvinced that Dunkin' Donuts is the shop to go to for breakfast. For most of its existence. Dunkin' Donuts' main product focus has been implicit in its name: donuts and coffee in which to dip them.  Also you can read about  History of the Culinary Arts. First time customer acquainted with this simple reputation were often overwhelmed by the wide varieties of donuts stacked end-to-end neat, mouthwatering rows. Playing catchup to the rest of the morning market, Dunkin' Donuts has only recently joined the breakfast sandwich game. According to spokesperson Andrew Mastroangelo, Dunkin' Donuts sells approximately one billion cups of coffee a year, for 62% of the company's annual store revenue/ Considering that coffee is the most profitable product on the menu, it's a good bet that those margins give the company room to experiment with its food offerings. Changing Course to Follow Demand Faced with the challenge of maintaining a relevant brand image in the face of fierce and innovative competition. Dunkin' Donuts pursued a time-honored business tradition – following the leader. The company now offers a competitive variety of espresso-based drinks complemented with a broad number of sugar-free flavorings including caramel, vanilla, and Mocha Swirl. Further more, ever-increasing competition in the morning meal market made an update to Dunkin' Donuts' food selection inevitable. The company currently focuses on begel and croissant-based breakfast sandwiches, including its new Oven-Toasted Breakfast line. On Every Corner Starbucks is known for its aggressive dominance of the coffee marketplace. When a competition opens a new store in twon. Starbucks doesn't worry. It just opens a new store across the street, in a vigorous one-upmanship that conquers new ground and deters competitors. But many who have struggled to compete with Starbucks have had to do so with limited resources or only a few franchises. Not so with Dunkin' Donuts, whose parent brand. Dunkin' Brands, also owns Baskin-Robbins. Simple Food for Simple People Dunkin' Donuts' history of offering simple and straight forward morning snacks has given It the competitive advantage of distinction as the anti-Starbucks-earnest and without pretense. Like Craftsman tools and Levi's jeans, the company offers a comforting sensibility appealing to simple, modest, and cost-conscious customers. The Sweet Spot Has a Jelly Center Dunkin' ‘Donuts is trying to grow in all directions, reaching more customers in more places with more products. Although Dunkin' Donuts often partners with a select group of grocery retailers such as Stop ; Shop and Wal-Mart-to create a store within-a-store concept, the company won't set up shop in just any grocery store. ‘We want to be situated in supermarkets that provide a superior overall customer experience,† he said. â€Å"Of course, we also want to ensure that the supermarket is large enough to allow us to provide the full expression of our brand. . . . which includes hot and iced coffee, our line of high-quality espresso beverages, donuts, bagels. muffins, and even our breakfast sandwiches. Furthermore, the outlet's location within the supermarket is critical for a successful relationship. â€Å"We want to be accessible and visible to customers, because we feel that gives us the best chance to increase incremental traffic and help the supermarket to enhance their overall performance. The company is banking on these mutually beneficial partnerships to help it achieve wides pread marketplace prominence. Dunkin' Donuts is a nationally known brand with a long reputation for quality, giving the company the benefit of not having to work hard to earn many customers' trust. But this strategy is not without its risks. In the quest to appeal to new customers, offering too many original products could dilute the essential brand appeal and alienate long-time customers who respect simplicity and authenticity. If Dunkin' Donuts' executives focus too narrowly on franchising new stores, they might not be aware of issues developing in long-standing or even recently established stores. Some older franchises seem long overdue for a makeover, especially when compared to the Starbucks down the block. For the time being, Dunkin' Donuts seems content to continue its methodical quest for continental domination of the coffee and breakfast market. In order to keep up with the latest health concerns, it has reformulated its cookies and muffins to avoid trans fats. The company has even begun shifting its donut production from individual stores into centralized production facilities designed to serve up to 100 stores apiece. Will Dunkin' Donuts strike the right balance of products and placement needed to mount a formidable challenge against competitors in both the breakfast and coffee markets?

Key Terms Assignment Example | Topics and Well Written Essays - 250 words

Key Terms - Assignment Example Ecological model is defined as an abstract in mathematical representation of an ecological system, which is studied to understand the actual system. They are formed by a combination of ecological relations and the gathered data in the fields. Family centered model is a way of working with both formal families and informal families across the systems of service to enhance their capacity to care and protect the children in their families as well as recognize the value of women’s employment. Family empowerment is defined a process by which the families access knowledge, skills and resources that help them to gain positive control of their lives as well and improve the quality of their life-styles High incidence disabilities are children who have different education needs and styles. They have communication disorders, mild mental retardation, and specific learning disabilities including attention deficit hyperactivity disorder (ADHD). Individualize education program is a mandated program by Individuals with Disabilities Education Act (IDEA) that gives opportunities to teachers, parents, school administrators, and students to work together and improve educational results for children with disabilities. Low-incidence disabilities are students who are characterized by blindness, low vision, deafness, hard-of-hearing, development delay, complex health issues, serious physical impairment, multiple disability and autism. Academic aptitude are those students who have potential to demonstrate exceptional strength in a specific area if academics. They have exceptional ability in one or more subject areas, that they performing beyond the norm for their age group. Continuum of Service is the range of placements, programs and services available for exceptional special needs of a student including regular classroom, to part time withdrawal to self-contained

Trying To Do Business In Mexico, Gringo Style Case Study

Trying To Do Business In Mexico, Gringo Style - Case Study Example These objectives primarily focus on enhancing the cost-efficiency of the company by reducing labor costs. Upon his arrival to Mexico with his family, Ted is greeted by his assistant plant manager and cultural mentor, Manuel and he promises Ted that the plant would become operational within two weeks. Eventually, the operations at the plant commence five weeks after the scheduled date which causes Ted to lose his trust in Manuel while, Manuel considers him too insensitive and impatient. As tensions between Ted and Manuel continue to grow, the efficiency levels at the plant continue to drop. Believing in the idea that cultural issues share no association with efficiency, Ted proposes three recommendations to address the problem including the dismissal of low performing workers and the implementation of an incentive-based pay system and a participative approach to decision-making. When the proposed schemes do not yield desired results, Ted realizes that Manuel did not fire five of the w orkers that should have been dismissed, and as a result of the differences in the labor laws of Mexico and US, the workers that were dismissed would be entitled to a severance pay. Feeling frustrated, Ted contemplates his future at the company and thinks that perhaps his criticisms of Mexican culture were indeed valid. 2. Discussion Questions 2.1 What mistakes did Ted make in his management of SterMexicana? The most fundamental mistake that Ted made in his management of SterMexicana is related with his convenient assumption and misguided belief that falsely led him to believe that his managerial expertise would transfer successfully to Mexico without the emergence of any significant issues. Therefore, during his time as the plant manager of the firm, Ted failed to acknowledge the cultural dimension of management in the formulation of appropriate strategies to address business problems, in his dealings with the company’s suppliers, and also in the decision-making process. For example, when Manuel showed interest in introducing Ted to the culture of Mexico, his reluctance in doing so was evident by his impatience to discuss more significant matters that were related to the business. By refusing to understand the dimensions of the country’s national culture, Ted ultimately developed recommendations and strategies which could not yield ideal results for the business. This observation corresponds with the analysis of Newman and Nollen who state that the financial performance of an organization is dependent upon the extent to which the management practices of a firm are in congruence with the national culture (753). When Ted did not demonstrate an interest in Manuel’s discussions of Mexican culture he was in fact ignoring valuable information that could have helped him in achieving his goals and formulating strategies for reducing SterMexicana’s labor costs. As suggested by Marchese in comparison with a highly individualistic U.S culture, the culture of Mexico is characterized by the presence of collectivism which is an aspect that emphasizes upon the significance of maintaining and valuing social relationships as members of a group (131). Ted’s implementation of a flexible working hours plan contradicted with this element of Mexico’

Different perspectives of the American Political System Essay

Different perspectives of the American Political System - Essay Example The aim of this paper is to critically assess the viewpoints regarding the political system of America. In order to assess the perspectives, two films have been selected namely â€Å"Wag the Dog† (1997) and â€Å"Mr. Smith goes to Washington† (1939). The 1997, Black comedy film by Barry Levinson rotates around the story of American politics and the sex scandals of the U.S. President. The President had luring relationships with a ‘firefly’ girl just before the Presidential re-election campaign. The film has reflected the idea that how the American Presidents, in order to hide their scandalous affairs, hire spin-doctors. The purpose of the spin-doctor was to ensure that he might divert the attention of the public, using media propaganda. He easily convinced the audience that America is at war with Albania. In short, it has been showed in the film that how media and other trusted agencies / institutions are in the hand of those, who control it as per their will (Levinson, 1997). Mr. Smith Goes to Washington is the story of good vs. evil in the American political system of the early 90’s. The story revolves around the United States Senate and how corruption leads its way in the American politics. Jimmy Stewart, who in the film is offered with a Senate vacancy, plays the character of Mr. Jefferson Smith. Since, Mr. Smith is an ideal, honest, innocent leader therefore he is easily personified by other evil senators and members of the American political system. The director of the film, Frank Capra, has shown Smith as an underdog who has to face severe challenges in order to survive in the intense competitive and corrupt American political system in order to attain some good (Capra, 1939). The message communicated to the audience through the film ‘Wag the Dog’ is that, that how easy it is to wipe out evidences or fact or to divert the attention of the

Grunert's Total Food Quality Essay Example | Topics and Well Written Essays - 1750 words

Grunert's Total Food Quality - Essay Example Furthermore, very well taste being free from Bovine Spongiform Enciphalopathy, genetic amendment and food additives are incentives for buying food. According to the Grunert's Total Food Quality Model the propensity towards augmented consumption of food can be correlated to a broader concern as regard to environmental issues. The major reasons that thwart consumers from purchasing food are: high price, be deficient in availability, gratification with conventional food, lack of reliance, the inadequate choice and paucity of perceived value. Although a number of consumers have shown curiosity in food, the food options of comparatively few people have been affected. Hence, expressed curiosity in food does not play a momentous role in food purchase and a disparity between positive attitude and behaviour is evident. Thus, acquaintance of consumers' cognitive structures and their impact on the purchase decision will indeed shed light on consumers' food purchases verdict that facilitates UK food firms in devising their marketing strategies. Economic theory has shown some confine in explaining the intricacy and multidimensionality of consumer activities. These bounds not only relate to the supposition of consumer rationality (that is utility exploiting behaviour) and flawless information. The majority of economic models use relative prices and disposable income or budget as illustrative variables of consumer deeds and treat every other sway (for instance social, economic and cultural factors) as cloaked or latent variables: quality inspection is one of them. The analysis of Grunert's Total Food Quality Model guides United Kingdom food firms devising marketing strategies that how consumer attitude deals primarily with predilections and how predilections are formed in the mind of the consumer. Marketing approaches to consumer attitude may be eminent as cognitive versus behavioural. According to Grunert the cognitive approaches underscore constructs dealing with cerebral structures and thinking processes; behavioural approaches stress upon direct links among the characteristics of the environment and behaviour. Both approaches are broadly accepted and accredited ways of analysing behaviour, with a high degree of complement. In this analysis one will ponder on the first approach and concentrate on consumer product knowledge, engagement and eagerness in the case of organic products. From a cognitive perspective, one can define consumer behaviour as the activities that people engross in when deciding, purchasing, and using goods and services to gratify desires. Such activities involve cerebral and emotional processes, besides physical actions. The cognitive approach is based on consumer acquaintance, product perception and the desires consumers want to gratify. Cognition is referred to as the dynamic cerebral constructs and processes involved in thinking, discerning and interpreting stimuli and events from the environment. It includes the information, sense and values that consumers have developed from their practice and stored in their memories. Whilst several aspects of cognition are sentient

Financial Crisis in the UK Banking Sector Essay

Financial Crisis in the UK Banking Sector - Essay Example Likewise, those that did not have access to important natural resources have been able to access the resource base and exploit the same to their advantage. The characteristic advancement of information and technological systems has made it possible for populations, firms and corporations to exploit emergent opportunities with ease. Notably, a significant percentage of the populations are taking practical steps to align their ways of life to the societal expectations with respect to improved standards of living. Apart from benefiting the society positively, inherent globalization has also had adverse impacts on the wellbeing of the society. Perhaps the sector that has been the most affected by the relative changes pertains to the economic segment. At this point, it cannot be disputed that the world economy directly affects the quality of life of the populations. This has further been occasioned by the characteristic integration that has tied local and regional economy to the wider glo bal economy. Thus operations at the global level have direct implications on the performance and general wellbeing of local, national and regional economy. This integration has made the financial sector susceptible to the negative impacts that stem from economic shocks. Coupled with the fragile nature of financial systems, the current economic instability has undermined the ability of the respective systems to cushion themselves against relative negative impacts. One of the economic problems that has posed great challenges to the UK government as well as the global financial system pertains to the 2008-2009 financial crisis. Seemingly, relevant authorities are taking practical steps to reinstate financial stability and enhance optimal performance. This is elemental in enabling them to attain a desirable state with respect to sustainable growth and development. Fundamentally, relative strategies are in line with their economic goals and objectives. Besides the challenges that are rel ated to economic integration, the UK financial sector has been compounded by governance problems. At this point, it cannot be disputed that governance problems contributed a great deal to the financial crisis that the country experienced at this particular time. In a society that is characterized by uncertainty, effective governance is important in enhancing optimal performance. Governance in this regard is all encompassing and ranges from the expertise and policies to the rules and regulations that are established to guide behavior and decision making. These need to be based on informed thought and to bear desirable outcomes; they need to be consistent with the economic changes being experienced in the market. Indeed, the fact that good governance is essential and contributes significantly to the integrity as well as stability of financial systems cannot be overstated. With this asset, corporations and organization can be able to maneuver their way through the volatile economic env ironment. It is against this background that this paper provides an in depth analysis of how poor governance in the UK financial sector contributed to the financial crisis that it experienced. To enhance coherence, the paper begins by explaining the notion and importance of good governance in the current financial corporate sector. Understanding Good Governance In his research, Hart (1995, p. 54) contends

Comprehensive Geriatric Assessment Paper Research

Comprehensive Geriatric Assessment - Research Paper Example Presenting complaints For the past five years Mrs.Rozario had been having an increasing memory loss and difficulty to move around for her daily functions. Previously she could walk or board the bus to town for shopping or to church. Her memory too became poorer. Executive functions slowly dwindled and she was unable to do many things herself. Help was needed on occasions. Sleep became disturbed. Moreover she seemed to withdraw from her friends and family whom she used to meet frequently and spend her time laughing and conversing with in better days. Recently she had a fall and had broken her femur. This had upset her further though that phase had been successfully passed over. Winter aggravated her mobility problem. Even with multiple complaints and problems she had been reluctant to approach anyone for help. She attributed her complaints to aging. It was at the behest of her son that she had now agreed to come. With the son’s assistance, the problems were all hopefully reveal ed. Past Medical history It said that she had been taking anti-hypertensives for the last twenty years. She used to be regular in her appointments with the physician but had lost that regularity of late. Previous medical history did not reveal any significant issue. Her pregnancies terminated normally and she has two children. Significant childhood diseases or history of immunizations were not remembered. Hospitalization had been only for her deliveries and her recent fracture femur. With no history of allergies, she could take any medicine. She was on 25 mg. Atenolol daily and had antacids occasionally. Analgesics and pills for sleeping comfortably had been prescribed at the local care center as and when she found it difficult to walk because of pain or could not sleep. She had ill-fitting dentures as she had lost weight recently. Cognitive impairment was present. Nutrition Her diet included more of cereals and porridges with small quantity of fruits and vegetables. Her dentures di d not fit well due to her loss of weight and so she would rather have a diet easily swallowed. She was having a diminished appetite. The history of constipation was elicited. Her son claimed that financial resources were not a hindrance to nutrition as he was looking after her. However she was staying alone and inability to cook her meals and have them could be the reason for the limited nutrition. Current weight was 50 kg. while her expected weight was 65 kg with reference to the Body Mass Index. Recent change in body weight had been noticed after she recovered from the fracture of the femur. Her current medications could have affected her appetite or digestion. Loneliness could be a factor which had limited her nutritional status. Vitamin or mineral supplementation was not her habit. She had mild depression for which she was not being treated. She used to read widely but her vision was failing and she had not met an ophthalmologist for assessment and reading had been stopped. Ther e were no independent transportation facilities unless her son arrived. She was not motivated enough to look after herself. It could be due to her failing cognitive functions. Consumption of her anti-hypertensive drug or other medicines was irregular and consisted of more than 3 drugs. The nutrition assessment was completed with a checklist. Mrs. Rozario agreed to most of the suggestions in the checklist. She ate less than two meals

Leave Your Name at the Border by M. Munoz Essay Example | Topics and Well Written Essays - 500 words

Leave Your Name at the Border by M. Munoz - Essay Example Another reason the Mexicans prefer to adopt the English names when they get to America is to make it easy for people who cannot easily pronounce Spanish names. However, Munoz feels that the main reason is the attempt to hide their identity. Munoz argues that it has now become a custom for Mexican parents to give their children English names. He emphasizes on this point by giving an example of how her nephews, as well as second cousins and other children in his hometown, have evaded their Spanish name in favour of English ones. This paper is an analysis of Manuel Munoz essay, which attempts to demonstrate how Mexican Americans are increasingly deserting their culture particularly their names to assimilate English ones. As Munoz argues, Mexicans appear not to be proud of their culture. As much as they argue that they change their names to make it easy for other people to pronounce, it is not understandable why they would do so even in their own hometown. It is for sure a cultural problem when people completely alter their own way of life to assimilate another one. Names are very crucial since they are used for identification. Most names tell where a person comes from hence his or her culture. Altering one's name is thus a sign that one does not want to be associated with his or her culture. However, I think that the Mexicans have a reason for this. It happens that a lot of stereotyping against the Spanish h speakers exists such that people tend to generalize when they speak of Spanish speaking people. A name being a way of identifying one as Spanish, then those who do not want to be associated with anti-Mexican stereotypes have no choice but to assimilate new culture and avoid being viewed as illit erate (Munoz, 2007). Self-identification is very crucial and the fact that some Mexican Americans cannot even pronounce their names well and are astonished when some do it correctly, demonstrate the extent to which they have run away from their own culture.

How Tim OBrien Shows the Negative Side of Vietnam Essay Example for Free

How Tim OBrien Shows the Negative Side of Vietnam Essay In Tim OBriens The Things They Carried, OBrien talks about all the parts of the Vietnam War. It shows all the horrors and negative sides of the war and what it can do to men. Many men lose their lives as well as their best friends and comrades. War also changes the soldiers into something else thats not themselves, something evil. The Things They Carried shows the negative side of war through the imagery of the shitfield, the mental affects of the war, the hatred that can be shown by each person, the way war changes people, and the loss of companions. In the shitfield one sees everything that is bad about the war. Its dirty and mucky and its just depressing all around. While in the field the soldiers are bombarded my artillery fire so they have to sink into the muck to hide themselves. One of the soldiers, Kiowa, gets hit with one of the shells. Norman Bowker tries to pull him out of the muck but he cannot. All the men try to pull him out but they cannot. They lose a friend in Kiowa, who is lost and buried in the field, and it scars all the men for life especially when they try to pull him out of the muck. The loss of a good friend stings for OBrien. OBrien even says that he went down with Kiowa that day and he lost a part of himself in that field. Everyone lost a part of themselves there. OBrien describes what he saw of Kiowa as he was going down under the muck. Kiowa was almost completely under. There was a knee. There was an arm and a gold wristwatch and part of a boot. There were bubbles where Kiowas head shouldve been (OBrien 168). OBrien going down with Kiowa shows that there are other negative effects such as mental ones. The mental effects of the war are also very negative in The Things They Carried. War messes with peoples heads and Tim OBrien shows it in his book. I couldnt sleep; I couldnt lie still (Chen 77). This is a cause of all the blood and gore the soldier has seen. And this doesnt just speak for the one soldier who said it, it speaks for all the soldiers. The first stage is not being able to sleep, the next stage is losing your composure. Then men start to become paranoid during the war and some go crazy. Rat Kiley is a good example of this. He is a medic and he starts to go crazy. He says he hears noises in the night that arent there. He says that he hears the voices of the people dying at night. OBrien thinks its from all the gore and blood he sees day in and day out and its just getting to him but either way he loses it. Rat tells someone he is going to shoot himself so he can get out of there because of an injury. The next morning he shot himself (OBrien 223). Rat Kileys plan works and he gets to leave, but he apologizes to all the men for losing it and in turn they dont rat him out for what he did. Not only does the war mess with peoples heads during the war but also at other times. The mental effects also extend to after the war. The awful memories of war stick with some of the men long after they return home from the war. The post war stress is too much for Norman Bowker. He finds that when he returns home that its not the same to him and he cannot find his place in society. He feels empty inside and ever since the shitfield he feels incomplete. The lingering memory of not being able to pull Kiowa out of the muck sticks with him. He feels that he died there with Kiowa and this causes him to be depressed. He often talks about it with his dad saying that he wishes he could have pulled harder to get Kiowa out but he just couldnt because of the smell. Norman wrote Tim OBrien a letter about his last book. He said it was very good book but that he should have put a chapter in about the shitfield. OBrien finds out that eight months later Norman killed himself. Normans writes OBrien a letter saying there was no letter and he hung himself with a jump rope. Tim OBrien kills a man while hes in Vietnam. He still feels the effects of killing the man and the guilt years later. He remembers it very well when his daughter asks him a question. The question was if he had ever killed someone. OBriens guilt over the man he kills comes from questions his daughter asks him about the war. He feels the sting years later (Martin 2). OBrien also revisits the site of the shitfield with his daughter. He starts to remember all the bad things that happened and it hurts him. OBrien hates the bad memories; he hates a lot of things. Some of the men start to show hatred toward people who usually arent hateful. The men start to turn on each other in stressful situations when they would have never done it before. Lee Strunk and Dave Jensen got into a fistfight. It was about something stupid, a missing jackknife, but even so the fight was vicious. Strunks nose made a sharp snapping sound, like a firecracker (OBrien 62). The men show hatred in the fight and over nothing important at all. In other circumstances it mightve ended there. But this was Vietnam, where guys carried guns, and Dave Jensen started to worry. It was mostly in his head (OBrien 62-63). Dave Jensen starts to get paranoid and he hates Strunk for it. One afternoon he began firing his weapon into the air, yelling Strunks name. late that same night he borrowed a pistol, gripped it by the barrel, and used it like a hammer to break his own nose (OBrien 63). This just shows how hate is a part of Vietnam. OBrien also shows hate toward some of his comrades. In a firefight OBrien gets shot and needs help from the new medic Bobby Jorgenson, but Jorgenson freezes because hes too afraid and forgets to treat OBrien for shock. This causes him much more pain over the months because the wound wasnt treated right and in time. OBrien hates Jorgenson for it. I wanted to hurt Bobby Jorgenson the way hed hurt me (OBrien 200). Months later OBrien and Jorgenson talk. OBrien realizes that Jorgenson is really sorry and he cant bring himself to say how he feels about it and just says its ok. I hated him for making me stop hating him (OBrien 200). This isnt like OBrien to be hateful. He has become something hes not. The war changes the men into bad things, things that arent themselves. OBrien talk about how the war changes himself and his personality at times. Id come to this war a quiet, thoughtful sort of person. Id turned mean inside. Even a little cruel at times. Its a hard thing to admit, even to myself, but I was capable of evil (OBrien 200). OBrien also talks about how one comes over innocent and but one leaves with a different identity. You come over clean and you get dirty and then afterwards its never the same (OBrien 114). Other authors talk about how OBrien shows the physical and mental devastation caused by the war. Nowhere in The Things They Carried does OBrien explain more clearly the psychic devastation wrought by wartime trauma (Neilson 193). One sees the effect of the trauma even if the characters previous personalities arent known. The killing also has a big affect on OBrien. OBrien also talks about how the man he kills changes him because it is such a big deal to take a life. The author describes the soldier he kills. He describes everything from his wounds to his figure. He was a slim, dead, almost dainty young man of about twenty. He lay at the center of the red clay trail near the village of My Khe. His jaw was in his throat. His eye was shut, the other eye was a star shaped hole. I killed him. (OBrien 203). Once OBrien killed this man he was broken in to Vietnam. He no longer was clean, he was now dirty. His first kill hastens his loss of innocence (Herzog 133). The soldiers in the war arent the only ones who were changed by Vietnam. One soldier brings his girlfriend from the states to visit him in Vietnam. He has her flown in through cargo planes and brought to his camp. At first she is glad to see her boyfriend and one can tell they are in love because they spend every minute together. She begins to get curious though and wonders off camp many times to explore. Then one night she goes missing and she is gone for a couple of days. She returns with the Greenies or Green Berets. She tells him not to ask and not to worry about it and acts like she has done nothing wrong. This happens many other times and the soldier can tell that he is beginning to lose her. When she begins disappearing with the greenies and taking part in the night ambushes, she melts into a small, soft shadow' (Chen 90). She becomes something she originally wasnt. Mary Anne starts to become one with Vietnam and she totally forgets about her boyfriend. In the end she is lost forever to Vietnam. It becomes impossible to distinguish between Mary Anne and Vietnam (Chen 91). Her boyfriend loses her and she is lost to Vietnam. Just one of many casualties of the war. But in his final story OBrien moves from his concern with moral corruption and war to one even more universally human: death (OGorman 306). OBrien also loses many things in the war. The worst part of the Vietnam War that OBrien shows is his loss of companions and friends. The author talks many times about his comrades throughout the book. He loses many people close to him personally and physically. There are five deaths in the novel. Ted Lavender, Curt Lemon, Kiowa, Linda, and the slim Vietcong soldier (Martin 1). The worst is the loss of his good friend. OBrien loses his good and best friend there, Kiowa, in the shitfield. This death is the most devastating to him because of how it happened in the muck and because he was a good friend. Kiowa was gone. He was under the mud and water, folded in with the war: Kiowas death actually makes him a part of the shitfield (Chen 93). It is also very devastating because all of the men feel guilt about it because they couldnt pull him out in time to possibly save him. Kiowas death is also pointless and has no purpose except to cause pain to his friends. In the story of Kiowas death, we find a combination of senselessness of war with the guilt that must be carried by other (Martin 2). This death affects everyone in the platoon but not all deaths are gruesome and ugly. An accident kills one of the young men, named Curt Lemon, and its described by OBrien as an almost beautiful death. They were just goofing. There was a noise, I supposed, which mustve been the detonator, so I glanced behind me and watched Lemon step from the shade into bright sunlight.when he died it was almost beautiful, the way the sunlight came around him and lifted him up and sucked him high into a tree full of moss and vines and white blossoms. (OBrien 70) The two soldiers are just playing a simple game and it all ends so suddenly. He is playing a game with another soldier, a game of toss with a smoke grenade, when he accidentally steps on a landmine (Martin 2). Lemon and OBrien werent as good as friends as him and Kiowa but it was a bothersome death because Lemon was so young. OBrien speaks of him stepping into the light, and then the blast sucks him up into the trees.what bothers OBrien is that Curt Lemon is just a kid (Martin 2). The death isnt all-beautiful. OBrien describes the mess that is made by the accident. The white bone of an arm.pieces of skin and something wet and yellow that mustve been the intestines (OBrien 89). Another casualty happens because of bad luck. Lee Strunk dies in battle during a firefight. OBrien describes the wound that Strunk gets. In October Lee Strunk stepped on a rigged mortar round. It took off his right leg at the knee.then he panicked. He tried to get up and run, but there was nothing left to run on (OBrien 65). Strunk didnt die right away but not all death occur right after the accident happens. Later we heard that Strunk died somewhere over Chu Lai (OBrien 66). The last death happens because of carelessness. Ted Lavender was always doped up and this in the end leads to his death. While going to the bathroom in the woods Lieutenant Cross is daydreaming and not keeping watch for enemy soldiers. While coming back from his bathroom break Lavender is shot in the head and killed on the spot. Cross never forgives himself for his death because he was daydreaming about girls and one of his men was killed. Several incidents in The Things They Carried reveal moments when the male soldiers cannot communicate with one another (Vernon 171). Death is only a small part of the whole picture. Tim OBrien shows many of the negative sides of the war to the reader in ways that the reader can see how bad war is. He uses the examples of his friends dying, the whole ordeal in the shitfield, how war changes the men including the mental effects, and by showing how hateful one can become because of the stressful situations and the things one sees. OBrien feels that he has to show all the negative sides of the war because he never wanted to go to war in the first place. Men go to war to fight battle that could be worked out peacefully and they fight and die for no reason. He feels that war is a bad thing and wants to show the reader that its a terrible thing and he does this very well. Even today war is a problem. Many young men are dying for no reason and it needs to stop. Works Cited Chen, Tina. Unraveling the Deeper Meaning: Exile and the Embodied poetics of Displacement in Tim OBriens The Things They Carried. Contemporary Literature 29.1 (spring 1998): 77-98. Herzog, Tobey C. Vietnam War Stories Innocence Lost. London: Routledge, 1992. Martin, Paul L. 24 March, 2008. http://plmartinwrite.blogspot.com/2007/11/things-they-carried.html Neilson, Jim. Warring Fictions. Mississippi: University Press of Mississippi, 1998 OBrien, Tim. The Things They Carried. New York: Broadway Books, 1990. OGorman, Farrel. The Things They Carried as a Composite Novel. War, Lit, and the Arts. Vernon, Alex. Salvation, Storytelling and Pilgrimage in Tim OBriens the Things They Carried. Mosaic (Winnipeg) 36.4 (2003): 171+. Questia. 19 Mar. 2008 http://www.questiaschool.com/PM.qst?a=od=5002093009.