Local History Museum and Tourist Office, Kepsey, New South Wales by Essay

Local History Museum and Tourist Office, Kepsey, New South Wales by Glenn Murcutt - Essay Example While living in Greek Island, Murcutt discovered how simple this architecture was with regard to rationale and inevitability. He was fascinated by how the whole procedure employed a limited number of materials that created a poetic architecture when understood. His profound understanding of the place and the simplicity involved created an influenced his search for suitable architecture in Australia. In 1965, Mercut returned to Australia and secured employment with Ancher Mortlock Murray, a doyen of Sydney architects, and Wolley. While here, Mercutt claims to have been influenced more by Ancher first as an architect then as a mentor in life. In 1969, he went ahead to set up an independent practice for which he worked as a sole operator in the later days. Glenn Murcutt is known as a country person. Among his significant preoccupations as an architect is the connection of his building to the nature, landscape and the bush. According to Murcutt, a building works as a filter between eleme nts and man. Among the major works is the Local History Museum and Tourist Office, Kepsey, in the New South Wales. This work features Macleay valley history before and even after the arrival of white settlers. It includes the pioneer cottage that is furnished using items collected from local communities to depict the native’s history. Here, the items displayed include bootmaking, aboriginal history, timber industry, natural history, military history, dairy history, historical vehicles, shipping, local country music, ceramics and glassware, and negative photography collection. Local History Museum and Tourist Office, Kepsey, New South Wales was constructed to meet the Meclay historical society need of a house that will store artifacts and contents of local history. The need to create a generally controlled environment to suit safe storage of the clothing,

Midterm Assignment Example | Topics and Well Written Essays - 1500 words - 1

Midterm - Assignment Example The fall of this age credited with the Dorian Invasion, which is believed to have happened around 1100 B.C., and which came to be the conclusive deathblow to the Minoan civilization (Lawall & Maynard 24). According to Greek legend, it was in this age that the Oedipus tragedy evolved, and the story later depicted in Aeschylus' Oresteia played out. This was the time of the famous Trojan War, which left the Trojans and Greeks alike bereft of some of their most beloved and courageous men who died as heroes on the incarnadine battle fields (Lawall & Maynard 34). This was the time of the wonderings of Aeneas and Odysseus after the war, and a time where the inhabitants of Mount Olympus interacted with the humans more than ever. Homer did not live during the time, which is named after him. He is believed to have lived three hundred years after the Homeric Age of which he wrote about in his epic poems (35). He is, of course, our most important literary source for knowledge of this period, com bining the history, religion, myth, and lore of many generations (Lawall & Maynard 37). The political institutions of the Homeric Greeks were exceedingly primitive. ... Practically his only functions were military and priestly. He commanded the army in time of war and offered sacrifices to keep the gods on the good side of the community (Lawall & Maynard 48). Although each little group of villages had its council of nobles and assembly of warriors, of these bodies had neither any definite membership nor status as an organ of government. The duties of the former were to advise and assist the king and prevent him from usurping despotic powers. The  functions of the latter were to ratify declarations of war and assent to the conclusion of peace (Lawall & Maynard 50). Almost without exception, custom took the place of law, and the administration of justice was private. Even willful murder was punishable only by the family of the victim. While it is true that the king for settlement, he acted in such cases merely as an arbitrator, not as a judge. As a matter of fact, the political consciousness of   the Greeks of this time was so poorly developed tha t they had no conception of government as an indispensable agency for the preservation of social order. When Odysseus, king of Ithaca , was absent for twenty years , no regent was appointed in his place , and no session of the council or assembly was held. No one seemed to think that the complete suspension of government, even for so long a time, was a matter of any critical importance. Just before the violent Doric invasions, the Achaeans fought the Trojans of Asia Minor. The chronicle of that war, the Iliad, furnishes the first clear picture of the early Greek religion as it evolved from a blending of Achaean, Dorian, Minoan, Egyptian, and Asian elements. This phase of Greek religion called Homeric, after the

Enzyme Kinetics of Acetylcholinesterase

Enzyme Kinetics of Acetylcholinesterase David Romero Perez Enzyme kinetics of Acetylcholinesterase and its behaviour in the presence of Edrophonium. Abstract The aim of the present study was to test the effects of edrophonium on the enzyme kinetics of acetylcholinesterase. The use of s-acetylthiocholine as a substrate with its breakdown by acetylcholinesterase and the later reaction into a coloured product, allowed the utilization of colorimetric technique in conjunction with spectrophotometry. A Michaelis-Menton and a Lineweaver-Burk plot showed edrophonium to be an acetylcholinesterase inhibitor that does not fit with the classical descriptions of competitive, non-competitive or uncompetitive inhibitors. The results though were coherent with previous research that classed edrophonium as a mixed inhibitor at concentrations similar to the ones used in the present study, 10 uM. On the contrary, the same study suggested that edrophonium behaves as a competitive inhibitor at concentrations of 0.1 uM but this concentration was not tested on the present study and, therefore, further research is required. Introduction Chemical reactions are the fundamental basis of all matter and, therefore, of life. The study of the chemistry relevant to life is called biochemistry and inside this discipline the study of enzymes has been of particular importance. Enzymes simply make rare chemical events common enough to allow the accumulation of, otherwise, improvable molecules or products required for life (Laidler, 1997). Thanks to millions of years of evolution the level of sophistication in biological systems has reached high levels, allowing fine-tuned regulation of enzymes and their products (Berg, Tymoczko and Stryer, 2012). Nonetheless, the study of the enzyme kinetics and how their regulation works had to overcome, with great efforts, the technological difficulties of such small and fast reactions (Laidler, 1997). The first studies done on enzyme kinetics were on fermentation. From ancient cultures to the present humans have use fermentation to produce alcohol and bread. But it was not until the 19th century that fermentation started to be studied. Fischer’s lock and key hypothesis was one of the first successful although not completely accurate attempts to explain the process (Laidler, 1997). On 1902 Brown studied invertase, using yeast and sucrose, discovering the Enzyme-Substrate complex (ES) (Kenneth, 2013). This provided the fundamental blocks for the development of the new-born biochemistry discipline. Another hallmark on biochemistry was the work of Leonor Michaelis and Maud Leonora Menten, 1913, Michaelis-Menten equation (E + S →↠ ES →↠ ES ´ → E + products). Their experiment failed but gave us important lessons on the importance of pH on enzyme reactions (Laidler, 1997). The pH is important because most, if not all, enzymes are active only at specific ranges of pH, and usually reach their optimum activity around 7.0 pH. This value is common in biological systems although specialized enzymes may require higher or lower values (Berg, Tymoczko and Stryer, 2012). Also, the previously mentioned researchers produced an easy way of visualizing the data in the form of a graph called the Michaelis-Menten plot. This graph allows quick recognition of important parameters like the maximum activity reached by the enzyme (Vmax) and the amount of substrate required to produce half Vmax (Km) (Berg, Tymoczko and Stryer, 2012; Laidler, 1997). The Michaelis-Menten plot will be used in this study to show both parameters in relation to the enzyme achetylcholinesterase. Acetylcholinesterase is an enzyme of vital importance for the nervous system. As an enzyme is a globular protein mostly released to the inter-synaptic space between neurons’ axons and dendrites. Its purpose there is to break down the neurotransmitter acetylcholine to prevent it from continuously activating acetylcholine receptors on the post-synaptic neuron (Berg, Tymoczko and Stryer, 2012). As with every enzyme other substances can interact with it or with the conformation of the E+S complex. These components are called inhibitors and are usually described as competitive, non-competitive or uncompetitive, although mixed inhibitors have been also described (Berg, Tymoczko and Stryer, 2012; Howard, 2007). For any chemical to be classed as an inhibitor it must have an negative effect on the Vmax and/or Km. The effect on those would decide what type of inhibitor the chemical is. If competitive the inhibitor binds to the catalytic site and Vmax remains the same while Km is increased. On the other side, if non-competitive, it would bind on a different location than the catalytic site, preventing the binding of the substrate. In this case Vmax would be the same but Km would be decreased. In turn, an uncompetitive inhibitor binds to the Enzyme-Substrate complex (ES) and both Vmax and Km, are decreased (Berg, Tymoczko and Stryer, 2012; Howard, 2007). In the present study the kinetics of achetylcholinesterase are tested in the presence or absence of edrophonium in order to investigate if it is indeed an inhibitor and to which class it belongs. These values were found using a combination of spectrophotometry and colourometry techniques. Spectrophotometry is a technique in which light crosses a cuvette containing the solutes. The content of the solution absorbs a certain amount of light depending on the concentration of the coloured chemical, therefore, less light will reach the detector at the other side of the cuvette. This is called the transmittance, and allows us to calculate the absorbance by subtracting the transmittance to 1 (1-T=A). The absorbance increases or decreases with the capacity of the solution to absorb light, giving an accurate reading of changes in solution composition or concentrations as is the case with enzymes in the presence of their specific substrate (Blauch, 2014; Reed, et al., 1998). This is calculated using the Beer-Lambert law which states that absorbance can be obtained by the equation A=Ecl (E=molar absorbitivity, c=concentration, l=longitude of the path of light which is commonly 1cm) (Anon., n.d.) Being the molar absorptivity (E) of 5-thio-2-nitrobenzoic acid 1.3610^4. The Beer-Lam bert equation can be rearranged (Anon., n.d.) to study the concentrations of unknown samples given that A and E are known and it provides the basis to accurate study of enzyme kinetics together with colourometric technique. Colourometry is based in the natural correlation between the amount of coloured chemical in a solution and the intensity of that colour. Therefore, by comparing solutions of known concentration of the same chemical it is possible to determine the concentration of the unknown concentration sample (Lancashire, 2011). To do so, a spectrophotometer is used by setting it up at the specific wavelength that corresponds to the colour of the reaction (Reed, et al., 1998). In some cases the product of the enzymatic reaction may not produce any colour and a modified substrate can be used. As it was explained before, acetylcholinesterase hydrolyses (breaks down) acetylcholine into an acetyl group and choline. The problem when trying to use the colourometric technique to measure the substrate production is that choline is colourless, hence the reason s-acetylthiocholine is used instead. The break down product thiocholine reacts with 5,5’dithiobis acid (DTNB) to produce 5-thio-2-nitrobenzoic acid (E=1.3610^4). This final product is yellow coloured and can be measured using the spectrophotometer at 412nm wavelength, allowing the precise study of acetylcholinesterase kinetics. Materials The agents used in this experiment were phosphate buffer (0.1 M), acetylthiocholine (15mM), DTNB reagent (6mM), acetylcholinesterase enzyme (0.3 u/ml) and water. All of them provided by UCLan School of Biomedical Sciences. In order to create the mixtures Gilson pipettes ( p20, p200 and p1000) with their respective tips were used. In addition, 3ml tubes were used for the initial adding of agents and 1ml standard plastic cuvettes for the spectrometer, which was also used to measure the absorbance. Methods The present study was divided in three parts. The aim of the first part was to find out the effect of enzyme concentration on rate reaction. The second part aimed to find the effect of different substrate concentration on rate reaction. Finally the third part studied the effect of edrophonium on enzyme rate reaction at different substrate concentrations. As a general note, every single dilution was kept at 3.0ml volume, using phosphate buffer as solvent. Also, every single dilution had 0.1ml AChE but in controls it was replaced with 0.1ml phosphate buffer to keep the 3.0ml volume. All mixtures were produce at room temperature. Plastic cuvettes were used to measure up absorbance in a spectrometer at 412 nm wavelength for two minutes, being the result the average per minute of those two minutes. For the first part of the study on effect of enzyme concentration on rate reaction the mixtures were produced as showed in table 1. AGENT VOLUME 1ST MIXTURE VOLUME 2ND MIXTURE VOLUME 3RD MIXTURE STOCK CONC. REACTION CONC. PHOSPHATE BUFFER 1.25 ml 1.2 ml 1.1 ml 0.1 M 50 mM ACETYLTHIOCHOLINE 0.1 ml 0.1 ml 0.1 ml 15mM 0.5 mM DTNB REAGENT 0.1 ml 0.1 ml 0.1 ml 6 mM 0.2 mM AChE 0.05 ml 0.1 ml 0.2 ml 0.3 u/ml 1st-0.005 u/ml 2nd-0.01 u/ml 3rd-0.02 u/ml WATER 1.5 ml 1.5 ml 1.5 ml n/a n/a Table 1 Reaction Mixtures. Before measuring every mixture the spectrometer was blanked with the correspondent control without the enzyme. The second part of the study looked at the effect on rate reaction of different substrate concentrations. The mixtures were produced with the volumes detailed in table 2. ACETYLTHIOCHOLINE (ml) PHOSPHATE BUFFER (ml) DTNB REAGENT (ml) AChE (ml) WATER Reaction conc of Acetylthiocholine (uM) 0.20 1.1 0.1 0.1 1.5 1000 0.10 1.2 0.1 0.1 1.5 500 0.05 1.25 0.1 0.1 1.5 250 0.02 1.28 0.1 0.1 1.5 100 0.01 1.29 0.1 0.1 1.5 50 0.005 1.295 0.1 0.1 1.5 25 Table 2 Composition of mixtures of acetylcholinesterase enzyme reaction without edrophonium. The effect of edrophonium on rate reaction was studied on the third part of the experiment. The mixtures were produced following table 3. Acetylthiocholine (ml) Phosphate Buffer (ml) DTNB Reagent (ml) Edrophonium (ul) AChE (ml) Water (ml) Reaction conc of acetythiocholine (uM) 0.20 1.1 0.1 100 0.1 1.5 1000 0.10 1.20 0.1 100 0.1 1.5 500 0.05 1.25 0.1 100 0.1 1.5 250 0.02 1.28 0.1 100 0.1 1.5 100 0.01 1.29 0.1 100 0.1 1.5 50 0.005 1.295 0.1 100 0.1 1.5 25 Table 3 Composition of mixtures of acetylcholinesterase enzyme reaction with edrophonium. Once the absorbance was recorded, the Beer-Lambert law equation was transformed to calculate the Velocity of 5-thio-2-nitrobenzoic acid (E=1.3610^4) production in Moles/litre/min achieved by every mixture: -A=ECL → C=A/E (L equals 1 per 1 cm of light path length inside the spectrophotometer cuvettes). The full calculations can be consulted in appendix 1. Results For the first part of the study the effect of enzyme concentration on rate reaction was measured and the velocity on nM/L/min was calculated and noted in table 4. Acetylcholinesterase concentration in u/ml Velocity of reaction in ÃŽ ¼M/L/min 0.005 2.05 0.01 3.97 0.02 7.8 Table 4 Calculated Velocity of reaction by acetylcholinesterase concentration. The velocity was plotted against enzyme concentration in graph 1, which shows a linear relationship between both parameters. Graph 1 Enzyme reaction of acetylcholine in response to enzyme concentration. Next the velocities of enzyme reaction at acetylthiocholine concentrations ranging from 25-1000 ÃŽ ¼M in the presence or absence of edrophonium were calculated and noted in table 5. Reaction concentration of Acetylthiocholine (ÃŽ ¼M) Velocity of reaction without edrophonium (ÃŽ ¼M/L/min) Velocity of reaction with edrophonium (ÃŽ ¼M/L/min) 25 2.5 0.15 50 2.87 0.95 100 3.6 1.25 250 3.75 2.57 500 4.34 2.65 1000 6.62 3 Table 5 calculated Velocities of acetylcholinesterase enzymatic reaction with and without edrophonium. Using the data from table 5 a Michaelis-Menton graph was plotted in graph 2 in order to reveal changes in Vmax and Km in the presence or absence of edrophonium. Graph 2 Michaelis-Menton plot of acetylcholine in the presence or absence of edrophonium. Clear differences on Vmax and Km were found between mixtures with or without edrophonium. In its presence Vmax dropped from 4.34 uM/L/ml to 3.01 uM/L/ml. On the contrary, the amount of substrate (s-acetylthiocholine) required to achieve 50% of Vmax was increased from 30 uM/ml to 100 uM/ml. There was a problem with the higher concentration mixture of the absence condition as it produced a higher than expected absorbance. This was examined in the discussion section. A Lineweaver-Burk plot (graph 3) showed the same results with decreased Vmax and increased Km. Graph 3 Lineweaver-Burk plot acetylcholinesterase in the presence and absence of edrophonium. In agreement with what was observed in graph 2, the graph showed that edrophonium is an acetylcholinesterase inhibitor. The kind of inhibitor it belongs to was examined in the discussion section. Discussion When comparing the Michaelis-Menton and the Lineweaver-Burk plots with the standard results of competitive, non-competitive and uncompetitive inhibitors (Berg, Tymoczko and Stryer, 2012), it became clear edrophonium did not belong to any of those. This can be explained by understanding the mode of action of a given inhibitor with the enzyme-substrate complex. Different inhibitors interact with different parts of a given enzyme or at different moments. A competitive inhibitor â€Å"competes† with the substrate for the catalytic site of the enzyme. As a consequence, the Vmax is reduced but if the concentration of the substrate is increased, more substrate would reach the catalytic site, nullifying the effect of the inhibitor although increasing the Km. An uncompetitive inhibitor does not bind to the catalytic site but somewhere else on the enzyme. It binds only once the E+S complex has been formed, decreasing the reaction rate regardless the substrate concentration. As a result the enzyme can not reach its normal Vmax and the Km is decreased. On the other hand, a noncompetitive inhibitor does not need the E+S complex to bind to the enzyme and does not decrease E+S formation. However, the E+S+I complex would not create a product, inactivating the enzyme. Basically, the noncompetitive inhibitor has taken a percentage of the active enzy me from the population, decreasing the Vmax but maintaining the same Km for the rest of the active enzyme population (Berg, Tymoczko and Stryer, 2012). The results of the present study suggest that edrophonium decreases the Vmax whilst increasing the Km and this effect can not be overcome by increasing substrate concentration. As a result, it can be classed as a mixed inhibitor, which inhibits the binding of the enzyme to the substrate and, at the same time, inactivates a proportion of the enzyme population (Berg, Tymoczko and Stryer, 2012). This has been supported by previous research (Robaire Kato, 1975) that found edrophonium to be a competitive inhibitor at concentrations of 0.1 uM but a mixed inhibitor at concentrations like the used in the present study, 10 uM. There were some limitations with the materials used. Plastic cuvettes were used instead of glass ones which are more suitable for organic solvents (Reed, et al., 1998). Also, the relative pipetting inexperience of the researches might have affected the accuracy of the resulting mixtures, hence the odd results for the mixture of higher substrate concentration on the absence condition. In future research it is recommended to improve pipetting accuracy maybe by using an automated pipetting system. Also, the timing in enzymatic reactions is critical, as these reactions occur often in seconds or even milliseconds (Laidler, 1997). Therefore, a multiplate spectrophotometer reader could be used to measure the absorbance of the mixtures. This would avoid any potential differences and delays from the moment the mixture is done to its reading. Also, lower concentrations of edrophonium (0.1 uM) should be tested to corroborate Robaire and kato’s (1975) research. In conclusion, in agreement with previous research (Bonaire Kato, 1975), the data points at edrophonium as an acetylcholinesterase mixed inhibitor at least at high concentrations (10 uM). Nonetheless, it needs to be confirmed in future research that edrophonium is also a competitive inhibitor at low concentration. At the same time, the technique could be optimized by the use of automated means in order to improve accuracy given the odd results produced by poor pipetting accuracy. References Anon (n.d.) Beers Law. Available: http://teaching.shu.ac.uk/hwb/chemistry/tutorials/molspec/beers1.htm. Last accessed 15th Jan 2014. Berg, J. M., Tymoczko, J. L. and Stryer, L. (2012) Biochemistry, 7th ed. New York: Freeman. Blauch D. N. (2014) Spectrophotomery. Available: http://www.chm.davidson.edu/vce/spectrophotometry/Spectrophotometry.html. Last accessed 15th Jan 2014. Howard, A. J. (2007) Enzyme inhibition and regulation, CSRRi,iit, [online]. Available at: http://csrri.iit.edu/~howard/biochem/lectures/enzymeinhibition.html. Last accessed 15th Jan 2014. Kenneth, A. J. (2013) A century of enzyme kinetic analysis, 1913 to 2013. FEBSLetters. 587, 2753-2766. Laidler, K. J. (1997) A brief history of enzyme kinetics. In: A. Cornish-Bowden ed. New Beer in an Old Bottle: Eduard Buchner and the Growth of Biochemical Knowledge. Valencia: Universitat de Valencia, pp. 127-133. Lancashire, R. J. (2011) EXPERIMENT 36 COLOURIMETRIC DETERMINATION OF PHOSPHATE. Available: http://wwwchem.uwimona.edu.jm/lab_manuals/c10expt36.html. Last accessed 15th Jan 2014. Reed, R. Holmes, D. Weyers, J. Jones, A. (1998) Practical Skills in Biomolecular Sciences. 4th ed. Essex: Pearson. 310-313. Robaire, B., Kato, G. (1975) Effects of Edrophonium, Eserine, Decamethonium, d-Tubocurarine, and Gallamine on the Kinetics of Membrane-Bound and Solubilized Eel Acetylcholinesterase. MOLECULAR PHARMACOLOGY. 11 (6), 722-734. Appendix 1 Velocity calculations Normal absorbances (nM) Divided by E Velociy (ÃŽ ¼M/L/min) 1/Velocity 0.034 2.5 0.4 0.039 2.87 0.35 0.049 1.3610^4 3.6 0.277 0.051 3.75 0.266 0.059 4.34 0.23 0.090 6.62 0.15 absorbances in the presence of edrophonium (nM) Divided by E Velociy (ÃŽ ¼M/L/min) 1/Velocity 0.002 0.15 6.6 0.013 0.95 1.05 0.017 1.3610^4 1.25 0.8 0.035 2.57 0.39 0.036 2.65 0.37 0.041 3 0.33

Representation of Colors in Margaret Atwoods The Handmaids Tale Essay

Representation of Colors in Margaret Atwood's The Handmaid's Tale Imagine if you can, living in a world that tells you what you are to wear, where to live, as well as your position and value to society. In Margaret Atwood's novel, The Handmaid's Tale, she shows us the Republic of Gilead does just that. Offred, the main character, is a Handmaid, whose usefulness is her ovaries. Handmaids are ordered to live in a house with a Commander, his wife, and once a month attempt to become pregnant by the Commander. Throughout Atwood's novel, you will notice she uses different colors for her characters clothing that correspond to their position and place in the Republic of Gilead. They become aware of people's statuses by the color of their garments. The colors of dress that have been used are red, blue, green, white, black, and khaki. Going into detail, I will show the social rank that each color represents in the novel, and my interpretation of them. The Handmaids are the only ones wearing red dresses, and several references are made towards the comparison of blood. "When Offred is in the room, which she refuses to call her own, she hears the bell to signal her time to go to the market. Getting up she puts on her red shoes and her red gloves, all the while thinking, everything except the wings around my face is red: the color of blood, which defines us. The dress she wears is also red, being ankle-length as well as long sleeve. The only item she wears that isn't red is the white wings around her face to keep her from seeing, as well as from being seen. Leaving the room, she walks down the hall, and heads for the stairs. She knows there is a mirror on the hall wall. If she turns her head so that the white wings framing her face direc... ... responsible for conceiving and giving birth for a Commander and his wife wear red. The Commander's wives wear blue which is the most prestigious color worn by a woman. Guardians, as well as Martha's, wear green, which is not an authoritive color, putting them in a lower class. White is the color to be worn only by the virgin daughters until they are given to a soldier to marry. Econowives are wearing dresses that are mixed colors because they have multiple functions and little value. The Republic of Gilead believes in showing levels of hierarchy, by the color of clothing worn. Works Cited Atwood, Margaret. The Handmaid's Tale. New York: Anchor Books, 1986. Snodgrass, Mary Ellen. Cliff Notes on Atwood's The Handmaid's Tale. Lincoln: Cliff Notes, Inc., 1994. Webster's New World Dictionary, Third College Edition. New York: Simon & Schuster, Inc., 1988.

Polymer

1. Important characteristics required for materials in Automotive Engineering Polymers have been used in the automotive industry for many decades. It is regarded as an efficient material as it is very durable and could significantly reduce production costs. However, as technology advances, new polymers are found and better alternatives are paved for the automotive industry. The vehicles we see today are very different than that of the yesteryears. This proves how far the automotive industry has advanced through technology. This eventually improved the built quality of vehicles in terms of safety, comfort, and performance.Plastics have greatly contributed to the advancement of the automotive industry. Although some may perceive that plastics yield a poorer built quality (though in some cases, it may be true), it actually is a better alternative in an engineer’s point of view. The reason why we have a contrast of opinions regarding the use of plastics is because of the type of p lastics being used. Therefore, the characteristics of the material are a very important factor in achieving good built quality. The automotive industry is constantly looking for alternatives to keep the production costs low.In order to achieve that, the engineers adapted to the use of plastics on certain parts. The question was – was this a good idea? Over the years, it became evident that it really is. Hence, we see modern cars with plastic bumpers, plastic door handles, plastic mirror housing, etc. The engineers had to bear in mind that what they require is a durable and robust plastic material. They had to consider something that is able to deform upon minor collisions, and be able to return back to its original shape (reversibly deformable). The benefit of this idea is so that vehicle owners do not have to change the bumper for minor accidents.However, plastics have a limit to their reversible-deformation property. It could tolerate impacts of up to a certain degree, but beyond that, it would be a permanent deformation. But then again, it is a lot better than to repair a bumper made of metal isn’t it? Thus, the bumpers are made of materials that are able to withstand light and medium impacts. Considering the fact that plastic parts are relatively lighter than metal or wooden parts, this would improve a vehicle’s performance, which will eventually make the machine more efficient.As of today, plastic parts are known to be the most effective material that could save weight and yet be strong and durable. Cost has always been a challenge in the automotive industry. For many years, engineers have been working on alternative materials. A good example is the use of wood for certain parts like the steering. It would certainly be cheaper than steel, but come to think about the time taken to craft a circular shape out of wood, it would in the long run cost more than the latter.Thus today, we find polymers used to replace these parts because it is in fact a lot cheaper and a lot easier to build. Some car owners of the 50’s and 60’s experienced this little problem when they park their cars out in the sun. They would return to their car and grab their stainless steel door handle and â€Å"ooh!! †. Yes, it is a very good heat conductor. Very obviously, replacing a stainless steel door handle or gear knob or steering wheel with a plastic material is a brilliant idea. But the problem is whether or not it is able to withstand the heat.Many first perceived plastic products to be inferior to high temperatures. However, technology proved them wrong. We have cars today with many plastic exterior parts that are able to withstand heat for years. It is indeed very important to analyze the feasibility of the use of a different material which has not been tested before. Many considerations are taken so that the parts used are well suited for its intended purpose. Plastics have proved to be a great alternative in automo tive engineering, paving a bright path towards the future.

Piaget and Vygotsky Essay

In this Essay I will compare and contrast the theories of Piaget and Vygotsky. They both were influential in forming a more scientific approach to analyzing the cognitive processes of the child active construction of knowledge. They both developed their own ideas of child development and they believed cognitive development in children took place in stages. However they were distinguished by different styles of thinking. Piaget thought that children actively construct their own cognitive worlds and they adapt their thinking to include new ideas because additional information furthers understanding. He stressed that to make sense of our world we organize our Schemata or experiences. We connect one idea to another. We also adopt new ideas. Adaptation is by assimilation, which occurs when individuals incorporate new information into their existing knowledge into an existing pattern of behavior of schemata (example). Piaget refers to Schemata or schemas to the way we organize our knowledge. We can think our knowledge as units and each of them related to aspects of the world including actions, objects etc. (referencing ) Accommodation occurs when individuals adjust to new information. Piaget thought that equilibrium occurs when is a balance between assimilation and accommodation. He believed equilibrium schema is both the category of knowledge as well as the process of acquiring that knowledge. As experiences happen and new information is presented, new schemas are developed and old schemas are changed or modified. An example is, say a child sees a crow and a pigeon in the sky, and is told that they are birds. The child then forms a bird schema defined as â€Å"something that flies†. The next day, he goes out and sees a seagull, which easily fits into his existing bird schema. This is called assimilation, when we take new experiences/knowledge and put them in our existing schemas (or categories). The next day, a child goes out and sees a plane in the sky. Whilst this fits the definition of â€Å"something that flies†, it seems to be quite different than the other birds he has seen, and he is told that this is not a bird. To explain this, the child forms one large category of ‘flying things’, with two sub-categories; birds and planes. This process is called accommodation, where we change our existing knowledge structures to account for new information that doesn’t fit. Piaget also believed that we go thought four stages in understanding the world. Each stage is aged related and consist of a distinct way of thinking, a different way of understanding the world. This theory is known as Piaget’s Stage Theory because it deals with four stages of development, which are sensorimotor, preoperational, concrete operational and formal operational. ( referencing ) On the other hand, Vygotsky believed that children actively construct their knowledge. He gave social interaction and culture far more important roles in cognitive development than Piaget did. Vygotsky socio cultural cognitive theory emphasizes how cultural and social interactions guide cognitive development. He portrayed the child development as inseparable from social and cultural activities. Vygotsky argued, â€Å"learning is a necessary and universal aspect of the process of developing culturally organized, specifically human psychological function† (1978, p. 90). In other words, social learning tends to precede development. He believed that the development of memory, attention and reasoning involves learning to use the inventions of society, such as language, mathematical systems and memory strategies.( referencing) Piaget believed that development had to come before learning; Vygotsky believed that development and learning worked together though socialization and language. Vygotsky gave language a huge role in development. For vygotsky Language plays two critical roles in cognitive development. First language is the main means by which adults transmit information to children. Secondly, Language itself it is a very powerful tool of intellectual adaptation. Vygotsky believed that language develops from social interactions, for communication purposes. Later language ability becomes internalized as thought and â€Å"inner speech†. Thought is the result of language. Piaget thought that there was a connection between biological and cognitive development. Vygotsky believed that knowledge from social interactions spurred cognitive growth and development. Even they had really big differences; they both believed that social interactions played an irreplaceable role in cognitive development. Piaget thought that cognitive development is influenced by social transmission (learning from others). Vygotsky believed that social interactions were an instrument in development and that it heavily influenced thoughts and language. Piaget strongly considered that the developmental ages of students determined where they should be in the learning process. Vygotsky took that idea further by comparing the learner’s actual development to their potential development. He called this area of â€Å" zone of proximal development. ZPD is the range of tasks that one cannot yet perform independently, but can accomplish with the help of a more competent individual. For example, a child might not be able to walk across a balance beam on her own, but she can do so while holding her mother’s hand. Since children are always learning new things, the ZPD changes as new skills are acquired. Piaget stages are hierarchical. Each of Piaget’s stages must be complete before moving to the next one. Vygotsky’s theory does not depend on time. Piaget stages imply that children cognitively develop on their own, without the help of someone or something. Vygotsky concentrates more on social interactions and aide given to a child when develops. Vygotsky Scaffolding is the kind of help, assistance and support that enables a child to do a task which they cannot quite manage yet alone and which it will help them in the future to be able to make that task or similar on their own. For example: In a school laboratory science class, a teacher might provide scaffolding by first giving students detailed guides to carrying out experiments, then giving them brief outlines that they might use to structure experiments, and finally asking them to set up experiments entirely on their own. ‘What the child can do with assistance today she will be able to do by herself tomorrow’ (Vygotsky, 1978, p.87). Both these educators contributed to the present day ideas of constructivist learning. Both offer some incredible insight into possible ways children learn and byusing there theories it is possible to create a more conductive learning environment for the child.