A for Alienation Essay Example for Free

A for Alienation Essay Alienation is a common theme in all writing; however, in The Scarlet Letter by Nathaniel Hawthorne, never has alienation been so vividly accounted. The Scarlet Letter is a story about Hester Prynne, a woman who commits adultery against her husband named Roger Chillingworth, with the local reverend named Arthur Dimmesdale; the result is a strange child named Pearl. The plot thickens as the mistress and the reverend strive to keep their sin a secret, and as Chillingworth appears back in town hiding his true identity; it climaxes on a scaffold where all secrets are revealed. Alienation is a heavy theme throughout the book, and it adds an incredible twist to see its affect on the characters. Alienation is portrayed through symbols, behavior, and drama with Hester, Pearl and Dimmesdale. Each character is associated with an important symbol that sets them apart from society. They also each deal with their alienation in different ways with different behaviors, and they are treated differently by society causing drama. In the end, some can deal being outcasts from society, but some cannot. Hester, the main character of the book, is most evidently alienated from society for her sin. The most important symbol in the book, the embroidered A on her bosom, sewed on as punishment for adultery, is also a symbol for alienation. She is different from all of society because of that mark, and can never live a normal life because of it. Let her cover the mark as she will, the pang of it will be always in her heart, (38), said a townsperson at first sight of the scarlet letter. As seen in this quote, society will always look at the scarlet letter as a wall between themselves and Hester. Hesters behavior shows how greatly she is affected by her alienation. Lonely as was Hesters situation and without a friend on earth who dared to she herself, she, however, incurred no risk of want, (57); in this quote one sees how being alienated from society can cause a person to become an introvert and become a lifeless body as Hester had become. There is a lot of drama surrounding Hester; all of society looks at Hester in shame. This complete shun from society drives Hester to live in an isolated cottage away from people. In this little, lonesome dwellingHester established herself with her infant child, (57). This particular dramatic  event alienated Hester geographically as well as socially. Hesters alienation also causes others to become alienated like her daughter and the one she has an affair with; however, Hester is most sharply alienated from all. Hesters daughter, Pearl, is also alienated from society. Her alienation has different circumstances, however, because she was born an alien, she did nothing wrong. Since she is the product of sin, many consider her a demon child with supernatural powers. For this reason, she herself is a symbol of her alienation; It [Pearl] was the scarlet letter in another form; the scarlet letter endowed with life! (70). She is compared to Hesters symbol of alienation, but she is a breathing, living form of the same symbol. She alienated herself and her mother from society. She is not your normal child, she acts very different; She [Hester] could recognize her [Pearl] wild, desperate, defiant, mood, the flightiness of her temper, and even some of the very cloud-shapes of gloom and despondency that had brooded in her heart, (63). In this description of Pearls behavior, we see a child that does not fit in your normal Puritan mold; she is a child filled of energy, character, and mischief. She finds a way to live a happy life regardless of being an outcast from society. Because of Pearls behavior and her mothers sin, lots of drama occurs around the possession of the child; Women it is thy bandage of shame! It is because of the stain which that letter indicates, that we would transfer thy child to other hands, (76). Here, Governor Bellingham is trying to take Pearl from her mother to give her a normal life in attempt to raise the child into your average, molded Puritan. Pearl is a free willed little girl who circumstantially is outcasted by society. Arthur Dimmesdale, the local reverend, is Pearls father; however, this is a secret kept from society and is revealed in the final scene. Dimmesdales secret guilt alienates him internally from everyone around him. His hidden sin is eating him alive while he continues to put a mask on and preach to society as if nothing is wrong. This hidden secret is symbolized in the book as an unknown marking on his chest over his heart. With a convulsive motion he tore away the ministerial band from before his breast. It was revealed!  (172); here, Dimmesdale reveals the markings on his chest to all of society and reveals his secret. This marking, weather it be a scarlet letter or not, is what symbolizes his alienation. It is an internal alienation from the outside world, and is not known by society until this moment. His behavior prior to this event should signs of a deep illness, not curable by any medicine. His nerve seemed absolutely destroyed. His moral force was abused into more than childish weakness, (109). Dimmesdale is weak in spirit and in health due to his extreme guilt alienating him from society. His behavior reflects his health which is in jeopardy due to his secret. This extreme pressure causes dramatic events to occur before the final climax. Walking in the shadow of a dream, as it were, and perhaps actually under the influence of a species of somnambulism, (101). The author here describes Dimmesdales journey to the scaffold one night; this night he can take the guilt no longer. It describes him to be in another world controlled by his guilt. He is alienated from all when he is in this frame of mind, and this can be seen through dramatic events such as this. Dimmesdales secret sin has caused his character to change considerably while alienating him for the rest of the town. The three aliens in this story have different types of alienation, and are under different circumstance too; nevertheless, the simple fact remains, they are alienated from their surroundings. Each character deals with their alienation a different way, and this is evident at the end of the story. Dimmesdale cannot take his inner guilt any longer and dies, Pearl fights through her problems to live a normal life, and Hester lives forever in her sin on her own. Through symbols, each characters behavior, and the drama occurring in their lives, alienation can be depicted with each character; however, the outcome of their alienation is governed only by the inner qualities of the character that the author has created. This reoccurring theme in literature has never taken a similar twist of outcomes, and it has brought interest, excitement, and meaning to the story.

Sustainable agriculture Essay Example for Free

Sustainable agriculture Essay Organic foods are defined as foods without pesticides, antibiotics,or gefetically altered organisms. Organic farming began in the late 1940’s in the united states, and in recents years it has grown into a multi-billion dollaer industry. Sales for organis foods in the past decade have increased annually by 20%. Its 20% growth is ten times as much as non-organic food’s growth. Organic food makes up only a fraction of the food market even though there are over ten million consumers. The sales of organic foods are expected to climb to over 6 billion dollars within the upcoming years. Soil is also a crucial component of the organic process. Soil is said to be organic when it has been deemed ‘clean’ for three years. Making a commitment to healthy eating is a great start towards a healthier life. Beyond eating more fruits, vegetables, whole grains, and good fats, however, there is the question of food safety, nutrition, and sustainability. How foods are grown or raised can impact both your health and the environment. This brings up the questions: What is the difference between organic foods and conventionally grown foods? Is â€Å"organic† always best? What about locally grown foods? Organic food, natural cleaners, green businesses, even organic clothing; natural and organic products continue to be the centre of attention for those seeking a healthier lifestyle, but just what is organic food, is this organic trend long-lasting, and what organic food facts provide compelling reasons to grow, shop, cook and eat organic food. Today, organic food accounts for 2% of global food sales and is growing at an average rate of 20% each year. Today, you can have your organic food delivered, buy it online, at your local grocery store, grow it yourself and order organic food at many restaurants. This continuing rise in demand creates a need for regulations to protect both consumers and farmers. Organic food is not the same thing as natural food. Natural refers to the way a food is processed rather than the ingredients. A food that is free of additives and preservatives, but contains commercially-produced ingredients, is considered natural. Organic food contains primarily organic ingredients, while natural foods may be made with items grown with the aid of chemicals as well as genetically modified ingredient and it is not just apples and bananas. Nearly every food available also has an organic version in today’s market. Organic milk, chicken, and even pasta can be found right on the shelves of your neighbourhood supermarket. Many leading food manufacturers are creating organic food in convenience packaging to fit into modern lifestyles. Canned organic tomatoes and frozen organic peas are among many options. Organic food is not bland and tasteless. In fact, most people claim organic ingredients are fresher and more flavourful than conventionally grown foods. Chemical residues, added ingredients, and hurried, mass production detract from the natural juices within fruits and vegetables. Organic food is free of chemicals, leaving nothing but pure, fresh flavour. Regulations and procedures for organic certification are still relatively new but organic farming and cultivation are not. Farmers were using natural, chemical-free methods of growing long before pesticides and fertilizers were available. As more research continues to reveal the dangers of these chemicals to both humans and the planet, consumers continue to explore the benefits of organic food. The advantages of arganic food are that you can choose to grow and/or buy food that is healthier for you, and the environment; cooking and eating organically also often offers more flavor and better tasting foods. Use organic farming methods and organic gardening tactics such as organic garden fertilizer and compost to grow your food; the organic food advantages and organic food benefits are significant for you, your family and the planet. Organic food benefits have been a hot topic for more than a decade now but it wasnt until relatively recently that these advantages were supported by more than just hearsay. Extensive research conducted over a number of years has proven that organic food not only tastes better than commercial foods, but it is also better for us and our children, as well as our animals, wildlife, and the environment as a whole. Care and maintenance of soil, and preventive farming methods like crop rotation create fruits and vegetables that contain up to 50% more vitamins, minerals, and other nutrients than intensively farmed foods. Encouraging natural and organic farming methods and gardening practices, will allow organic soil to rebuild and contribute healthy vitamins and minerals to feed the crops, and you. Organic foods have higher levels of many disease-fighting antioxidants and essential vitamins, including Vitamin C. Industrial pesticides and fertilizers used in intensive farming contain synthetic, toxic chemicals, residues of which remain in the food they are involved in producing. Organic farming uses natural, synthetic-chemical-free methods that produce foods much safer for the humans, as well as the animals, that consume them. And if you grow your own fruits and vegetables, using organic garden fertilizer, natural pesticide methods, and organic soil Such chemicals are responsible for a number of common allergies and have also been linked to serious diseases like cancer and Alzheimer’s disease. An organic diet significantly lowers these risks.

Synthesis and Characterization of a New Aromatic Diamine

Synthesis and Characterization of a New Aromatic Diamine The synthesis and characterization of a new aromatic diamine, 2,5-bis-(aminopyridine-2-yl)-1,3,4-oxadiazole (BAPO), containing pyridine and 1,3,4-oxadiazole moieties has been reported. An organophilic clay has been obtained via cation exchange reaction between the hydrochloride salt of BAPO and sodium montmorillonite (Na+-Mt‎). Basal space and thermal stability of this new modified organoclay were studied by wide-angle X-ray diffraction (XRD) and thermo gravimetric analysis (TGA) techniques. High thermal stability of BAPO-Mt in compared with conventional montmorillonite modified with aliphatic long chain surfactants is shown. A series of organoclay/polyimide nanocomposites (CPN) consisting of BAPO and benzophenone-3,3,4,4-tetracarboxylic dianhydride (BTDA) were also obtained by an in situ polymerization reaction followed by thermal imidization. Structural properties and thermal stability of the obtained CPNs were studied by XRD, TGA, differential scanning calorimetry (DSC), and differential thermal analysis (DTA). The glass transition temperature (Tg) is increased with respect to pristine PI for CPNs 1-3 wt.%. At high clay concentrations, the coagulation of organoclay particles results in a decrease in Tg. Based on the obtained results, CPN 1 wt.% showed the most improved thermal properties. 1. Introduction Polyimides (PI) have gained interests in both academia and industries due to their excellent thermal stability, good resistance toward organic solvents, and improved mechanical properties [1]. They have been have been applied widely in the areas of modern industries [2]. These super engineering plastics have found their way into aerospace, electrical/electronic applications [3], gas separation [4], cell processing, biochip design [5], coating, and composites [6-7]. However, some difficulties come from rigidity and poor solubility in processing of most PIs. Introduction of flexible ether and ester linkages between the aromatic rings of the main chain is an effective way to make these polymers more pliable [8]. In this regard, preparation of poly(ester-amide-imide)s [9], poly(ether amide imide)s [10], poly(amine–amide–imide)s [11] and poly(amide-imide)s [12] have been reported. It was shown that, the incorporation of rigid heterocyclic rings in the main chain of a synthetic polymer could provide excellent thermal and thermo-oxidative stability, which should be useful to decrease negative effects resulting from the introduction of flexible linkages mentioned above. Pyridine nucleolus, as a rigid symmetric aromatic ring, would contribute to the thermal stability, chemical stability, and retention of mechanical property of the resulting polymer at elevated temperature. Furthermore, the polarizability, resulting from the nitrogen atom i n the pyridine ring, could be suitable to improve their solubility in organic solvents [13]. Fujigaya et al. reported among the variety of polybenzimidazole derivatives, the pyridine-containing polymer is known to possess a better mechanical properties and significantly higher proton conductivity due to its higher acid doping ability [14]. On the other hand, it was known that, the thermal stability of polymers can be raised by the incorporation of 1,3,4-oxadiazole moieties into the polymer structure [15]. The outstanding thermal stability is ascribed to the electronic equivalency of the oxadiazole ring to the phenylene ring structure, which has high thermal-resistance [16]. Combination of inorganic materials with organic polymers is one the exciting topics that has been receiving increasing research attention during recent decades. Nanostructured hybrid materials showed wide potential applications in various areas such as in coatings [17], catalysis [18] and biotechnology [19], shape memory polymers [20], and fuel cells [21]. Organically modified sodium clay (Na+-Mt) has improved compatibility, hence higher efficiency of reinforcement, with the polymer matrix. It has been known that, the dispersion of small amounts reinforcing organoclay mineral with high-aspect ratios, such as layered silicate clays, can significantly enhance the properties of PI and its precursor poly(amic acid) (PAA). These improvements can include solvent resistance [22], ionic conductivity [23], enhanced fire retardance [24], increased corrosion protection [25], increased strength and heat resistance [26], decreased gas permeability [27], high moduli [28], and dielectric properties [29]. The enhancements in thermal and mechanical properties of polymer/clay nanocomposites (CPNs) are due to the lamellar structure of montmorillonite those results in high in-plane strength and stiffness, and a high aspect ratio [30-31]. The chemical structure of Na+-Mt consists of two fused silica tetrahedral sheets sandwich an edge-shared octahedral sheet of either aluminum or magnesium hydroxide [32]. The Ca2+ and Na+ ions adsorbed in the interlayer region are exchangeable with organic cations such as long chain alkyl ammonium [33-34]. These organoclays as compatibilizer may be suitable for polymer blends prepared with a low processing temperature. They have low thermal stability and start to decompose around 200 °C, whereas the melt-processing temperatures of most polymers are typically above 200 °C [35]. Furthermore, the preparation and processing of PI/organoclaynanocomposites is carried out at high temperatures, and the thermal decomposition of the long carbon chain of quaternary ammonium salts is inevitable. Thermal decomposition during processing can initiate/catalyze polymer degradation, in addition to a variety of undesirable effects during processing and in the final product [36-37]. To avoid the detrimental effects, modification of clay minerals with imidazolium [38] and phosphonium [39] salts have been noted. As another approach, using of aromatic amines and/or diamines, as swelling agents, has also been considered in the preparation of polyamide and polyimide (PI) nanocomposites [31, 36, 40-41]. Recently, we reported the synthesis of a new aromatic diamine, 2-(5-(3,5-diaminophenyl)-1,3,4-oxadiazole-2-yl)pyridine (POBD). Thermally stable poly(amide-imide)s [12], polyamides [42], polyimides [43], and PI/Clay nanocomposites [44] have been prepared using POBD. We noticed to the metal coordination ability of the 1,3,4-oxadiazole ring adjacent to 2-pyridyl group in designing POBD, Scheme 1. The ability of prepared hybrid materials for removal of the Co(II) ion have also been investigated [41, 45]. Thus, as part of our continuing efforts on the synthesis of polyimides with high thermal stability and metal ions coordination ability, in this work, we wish to report the synthesis and characterization of another designed aromatic monomer containing pyridine and 1,3,4-oxadiazole moieties. In this work, BAPO has been synthesized in four steps starting from 2-amino-6-methyl pyridine (1). The dihydrochloride salt of BAPO was used as a swelling agent for the modification of Na+-Mt. The novel modified organoclay (BAPO-Mt) was used in the preparation of PI/organoclay hybrids of BAPO/BTDA. Thermal stability of BAPO is higher than those for commonly used quaternary alkyl ammonium salts. Therefore, thermal degradation will be prevented during heat treatment needed for curing of poly(amic acid)s. The obtained films were studied by FT-IR spectroscopy, XRD, and SEM. The thermal properties were examined by TGA-DTA and DSC. 3. Results and discussion 3.1. Preparation of BAPO-modified organoclay The new diamine, BAPO 5, was synthesized in four steps. 2-Amino-6-methtypyridine 1 was acetylated with acetic anhydride, oxidized with potassium permanganate, and then alkaline hydrolyzed to give 6-amino-picolinic acid 4 [47]. Cyclo-dehydration to 4 with hydrazine sulfate in the presence of P2O5 in the mixture of POCl3 and concentrated phosphoric acid gave BAPO 5 in overall 20.0% yield (Scheme 2). The chemical structure of BAPO 5 was confirmed by FT-IR, 1H NMR, 13C NMR and mass spectrometry techniques. In the FT-IR spectrum, amino stretching vibrations observed at 3332 and 3202 cm-1. Vibration of C=N bonds of pyridine and oxadiazole rings appeared at 1575 and 1653 cm-1, respectively. The absorption band with medium intensity observed at 1273 cm-1 is related to vibration of C-N bond on the pyridine nucleolus. The amino protons also merged to appear as a broad singlet centered at 6.32 ppm in the 1H NMR spectrum. This peak was disappeared upon addition of D2O and a new peak related to HOD was appeared at 3.90 ppm. In the 13C NMR spectrum of BAPO (5) totally 6 signals observe that it is compatible with the desired structure, Figure 1. Molecular ion peak was observed as base peak in the mass spectra of BAPO, Figure 2. The ‎fragmentation pattern is shown in Scheme 3.‎ To prepare the organophilic clay (BAPO-Mt) via a cation exchange reaction, the Na+-Mt was initially mixed with a hydrochloride solution of the intercalating agent, BAPO 5. Scheme 4 presents a schematic drawing of the modification step. 3.2. Characterization of BAPO-Mt organoclay Figure 3 shows FT-IR spectra of BAPO, sodium montmorillonite, and BAPO-Mt. The spectrum of organoclay exhibits the characteristic bands of Mt and BAPO: N–H stretching at 3330 and 3206 cm-1, –C=N– stretching of the pyridine nucleolus at 1652 cm-1, –C=N– stretching of the oxadiazole ring at 1546 cm-1, stretching vibrations of the double bonds of the aromatic rings in BAPO at 1627 cm-1, and typical bands of montmorillonite at 1033 and 525 cm-1. Figure 4 presents wide XRD of BAPO-Mt and pristine clay. A strong peak is observed at 2à ¯Ã‚ Ã‚ ±Ãƒ ¯Ã¢â€š ¬Ã‚  = 8.95 ° for Na+-Mt, corresponding to the (001) plane, indicating that the interlayer spacing (d001-spacing) of Na+-Mt is about 1.0 nm. The interlayer  ­d001spacing can be calculated from peak positions using Bragg’s law: nÃŽ » = 2d sin ÃŽ ¸, where ÃŽ » is the X-ray wavelength (1.5418 Ã…). The reà ¯Ã‚ ¬Ã¢â‚¬Å¡ection peak of (001) in BAPO-Mt shifted to a lower diffraction angle at 6.90 °, corresponding to the larger d001-spacing (1.28 nm) than Na+-Mt. The replacement of sodium ions with the ammonium ions of BAPO seems to increase the d001-spacing of layered silicate. In general, a larger d001-spacing should assist the intercalation of the polymer chains and should also lead to better clay dispersion within the polymer matrix. Table 1 summarizes the diffraction peaks and the calculated d001-spacings of Na+-Mt and organophilic clays. The thermal treatment of pristine clay under nitrogen consists of two main stages. The first stage occurs from ambient temperature to 200 °C. In this step, free water molecules physically adsorbed on the external surfaces of crystals along with the hydrating water molecules around the exchangeable cation located inside the interlayer space are removed. The second stage is attributed to the dehydroxylation of the structural silanol units of the montmorillonite in the range of 200-700 °C. The temperature intervals of dehydration corresponding to these processes as well as the amount of water released depends on the nature of adsorbed cations and the hydration of the surface [50]. On the other hand, organically modified montmorillonite shows a four-step decomposition process. The vaporization of free water takes place at temperatures below 200 °C, while the surfactant’s decomposition occurs in the temperature range of 200–500 °C. Dehydroxylation of the structural s ilanol groups related to aluminosilicates occurs between 500–800 °C. The last step is the decomposition associated with the combustion reaction between organic carbon and inorganic oxygen [51]. The amount of loaded diamine can be estimated by TGA measurement. Figure 5 shows the TGA curves of the Na+-Mt, the BAPO-Mt, and BAOP. Pristine Na+-Mt contains a large quantity of water due to the intercalation of hydrated sodium (Na+) and hydrated calcium (Ca2+) cations inside the clay layers. These physically adsorbed water molecules are removed in the range from ambient temperature to 230 °C (ca. 3.81% weight loss). The virgin clay also undergoes a 6.36% weight loss within 230-598 °C related to dehydroxylation of the structural silanol units. Whereas, under the same condition BAPO-Mt shows a weight loss of about 10.6% within 230-598 °C related to surface dehydroxylation and thermal decomposition of the surfactant molecules within the organoclay galleries. The difference betwe en weight losses of Na+-Mt and BAOP-Mt within 230-598 °C (Δm = 4.24%) can be attributed to the weight of the loaded diamine. Therefore, the amount of loaded diamines (42.4 mg/g of clay) can be calculated from Eq. (1). Surface energy of Na+-Mt is lowered by the presence of the aromatic ammonium ions within the interlayer spacing. Therefore, the hydrophilic silicate surface transforms to an organophilic one. As seen in Figure 5, the thermal decomposition of the surfactant molecules occurs in two stags at 260 °C and 370 °C. These temperatures are higher than those of decomposition temperature of aliphatic long chain surfactants commonly used for modification of Na+-Mt, which occurs below 200 °C [52]. This study suggests that the BAPO-Mt can be used in the preparation of PI nanocomposites that need to be cured at elevated temperatures. The images obtained by SEM demonstrate significant changes on the surface of the BAPO-Mt. The Na+-Mt particles seem to be stuck together due to moisture (Figure 6a-b), but the organoclay particles are clearly separated in organically modified clay (Figure 6c,d). It seems that the hydrophilicity of the clay is reduced after modification reaction. This study is in accordance with TGA results. 3.4. Polymer Synthesis The present work reports the preparation and characterization of new polyimide CPNs. BAPO-Mt is used as the surfactant at different concentrations. Scheme 5 depicts the synthesis of the PI from the reaction of BAPO and BTDA through thermal dehydration of the poly(amic acid) intermediate. The FT-IR absorptions appearing at approximately 1786, 1727, 1366, 1094 and 722 cm-1 (Figure 7) indicate the presence of imide functional groups in the polyimide film [53]. The polyimide is also characterized by elemental analysis. The observed and calculated values for CHN analyses are in good agreement. Solubility test results (Table 2) show that the obtained PI is soluble in dimethylsulfoxide (DMSO) and concentrated sulfuric acid at room temperature and in other polar aprotic solvents such as, dimethylacetamide (DMAc) and N-methylpyrrolidone (NMP) at boiling temperature of the solvents. For this experiment, about 0.01 g of the polymer sample was examined in 1 ml of solvent at room and at boiling temperature of the solvents. The inherent viscosity of the 0.125 and 0.25 g/dL solutions of the polyimide were 0.36 and 0.39 dL/g, respectively (measured at 25 ± 0.5 °C in DMSO). 3.5. Preparation and characterization of PI/BAPO-Mt CPNs The preparation and characterization of polyimide CPNs with different concentrations of organoclay are also investigated. Scheme 6 shows a procedure for the preparation of PI/BAPO-Mt CPNs by thermal imidization according to method described earlier [44-45]. Figure 8 presents XRD curves of BAPO-Mt, and PI films with various organoclay contents. The lack of any diffraction peak in the XRD patterns of CPNs 1 and 3 wt.%, at 2à ¯Ã‚ Ã‚ ± = 2-10 °, can be attributed to the possible formation of nanocomposites of exfoliated structure. A wide and week diffraction peak at 2à ¯Ã‚ Ã‚ ± = 6.62 ° was displayed by CPN 5%, equaling a d00-spacing of 1.33 nm for the layered silicates in the CPN. The shift to higher interlayer d00spacing with respect to BAPO-Mt (2à ¯Ã‚ Ã‚ ±Ãƒ ¯Ã¢â€š ¬Ã‚  = 6.90 °, d001 = 1.28 nm) is due to the intercalation of the polymer within the organoclay galleries and the formation of an intercalated nanocomposite. Pure polyimide does not show any diffraction peak at 2à ¯Ã‚ Ã‚ ± = 2-10 °. The XRD data are summarized in Table 3. The glass transition temperature of the pure PI is observed at about 271.3 °C (measured by DSC), and the polymer does not show any melting endotherm. The decomposition of the polymer begins at 435.5 °C, and no thermal decomposition occurs below this temperature. To remove any adsorbed water, the polymer samples were heated to 150 °C and then cooled to room temperature prior DSC measurements. Figure 9 shows DSC curves of the PI and CPNs. The results are summarized in Table 4. As seen, the glass transition temperature increases dramatically from 271.3 °C for pure PI to 297.0 °C for CPN 1%. The restriction of the intercalated polymer chains within the clay galleries can be responsible for preventing segmental motions of the polymer chains [46]. However, further addition of organoclay up to 5 wt.% leads to a decrease in Tg. This decrease might be due to the aggregation of BAPO-Mt particles that reduces the interfacial interaction between organoclay and the PI matrix [47]. Both DSC and DTA methods show similar trends of changing in the Tg values upon increasing the organoclay content. Figure 10 shows TGA curves of the pure PI and CPNs. The results are given in Table 4. As seen thermo-gravimetery parameters such as temperature for %10 mass loss and initial thermal decomposition (TD) are increased for CPN 1%, remained almost unchanged in CPN 3%, and then decreased. Char yields are less influenced by the BAPO-Mt content. The drop in the thermal properties at high organoclay loading may be attributed to the better miscibility of polymer and organoclay phases at low organoclay concentrations. Like a superior insulator, the obtained multilayered carbonaceous silicate structure increase the total path of evaporation for small molecules produced during pyrolysis [24]. Based on DSC, DTA and TGA studies, it can conclude that CPN 1% has the most improved thermal properties. The morphology of the PI and CPN film surfaces was also studied be SEM. Some significant and interesting changes have been observed in the surface of CPN 1% with respect to virgin PI film, Figures 11a-d. As seen in the pictures, too many micro-cracks are observed in the background of both films, however, homogeneity of the film surface is increased in the CPN 1wt.%. Conclusion A new thermally stable organoclay has been prepared through the modification of Na+-Mt with BAPO. An X-ray diffraction study confirmed the intercalation of organic surfactant within the silicate layers. SEM images showed that some significant changes occurred on the surface of BAPO-Mt with respect to Na+-Mt, including a decrease in hydrophilicity. Furthermore, the high thermal stability of BAPO avoids pyrolysis during thermal imidization of poly(amic acid) intermediate. The preparation and characterization of new PI/BAPO-Mt CPNs with different contents of organoclay have also been investigated. CPNs 1-5% were prepared from the thermal imidization of a BAPO-Mt dispersion in a poly(amic acid) solution obtained from BAPO and BTDA. XRD patterns showed that exfoliated CPNs may be obtained with the organoclay content of 1-3 wt.%, but at higher clay loadings intercalated structure is significant. TGA-DTA and DSC measurements showed that Tg increases with increasing organoclay content loadin g to 1 wt.%, and then decrease thereafter. SEM images showed that CPNs 1% produces smoother film than that of the virgin polyimide.

MBA Admissions Essay - My Most Significant Leadership Role :: MBA College Admissions Essays

MBA Admissions Essays - My Most Significant Leadership Role During the last three years I have devoted a significant amount of time and energy to the betterment of young entrepreneurs, who in this country are mistreated, stripped of opportunities, and looked down upon. In my quest to start my own business, I faced many obstacles that I later found to plague all entrepreneurs in my country. Established family heads discourage their younger members from starting separate businesses; they would rather their younger members join them in the so called "safe business." Moreover, companies and government organizations will not award contracts to young people since older people earn respect for their age rather than their ideas in this traditional sub-continental culture. With an uncooperative family and no sources of funding, young entrepreneurs face little chance of success. In these difficult conditions, I realized there were many young people who were full of potential but lacked support. By meeting with these people, I motivated them to believe that together we could help improve collective situation. In October 1996,the seventeen of us founded the "Young Entrepreneurs Society" (YES). I served as the coordinator for the first two years. We figured that in order to get our message heard, we needed to prove ourselves a significant lot. We started with social activities like helping poor students with registration fees for matriculation exams and organizing blood donation activities, etc. We held our first seminar on the "Prospect of Software Development Business in Bangladesh and the Government's Role, " and five months later we had our second seminar on the "Obstacles for Young Entrepreneurs in Bangladesh' with the finance minister as the chief guest. MBA Admissions Essay - My Most Significant Leadership Role :: MBA College Admissions Essays MBA Admissions Essays - My Most Significant Leadership Role During the last three years I have devoted a significant amount of time and energy to the betterment of young entrepreneurs, who in this country are mistreated, stripped of opportunities, and looked down upon. In my quest to start my own business, I faced many obstacles that I later found to plague all entrepreneurs in my country. Established family heads discourage their younger members from starting separate businesses; they would rather their younger members join them in the so called "safe business." Moreover, companies and government organizations will not award contracts to young people since older people earn respect for their age rather than their ideas in this traditional sub-continental culture. With an uncooperative family and no sources of funding, young entrepreneurs face little chance of success. In these difficult conditions, I realized there were many young people who were full of potential but lacked support. By meeting with these people, I motivated them to believe that together we could help improve collective situation. In October 1996,the seventeen of us founded the "Young Entrepreneurs Society" (YES). I served as the coordinator for the first two years. We figured that in order to get our message heard, we needed to prove ourselves a significant lot. We started with social activities like helping poor students with registration fees for matriculation exams and organizing blood donation activities, etc. We held our first seminar on the "Prospect of Software Development Business in Bangladesh and the Government's Role, " and five months later we had our second seminar on the "Obstacles for Young Entrepreneurs in Bangladesh' with the finance minister as the chief guest.

Internet Censorship Means No Freedom of Speech -- Argumentative Persua

Picture it: you pick up your phone to read your email. You're expecting a message from a friend, who is sending you some information on breast cancer, but when you check your inbox there is instead a message from the server. It says the message that was sent to you from the address of your friend has been intercepted because it contained indecent material that did not comply with FCC regulations of the Internet. You call your friend only to find that the police have come and taken her away, and she is now facing up to two years in prison and/or up to $100,000 in fines. The message sent by your friend contained the word "breast," which by current FCC standards is indecent, and thus not permitted to be transferred on the Internet. Due to this, your friend is now subject to criminal charges.   Ã‚  Ã‚  Ã‚   Sound ridiculous? Unreasonable? Perhaps even a bit scary? It is all three of these things, but further, it is impending reality. This situation is very possible, in the very near future. On February 8, 1996, President Clinton signed the Exon Bill, part of the Communications Decency Act; a bill which makes the possibility of this situation a frightening reality. This bill will allow the government to censor the Internet, by any means it deems necessary. Under the CDA the "seven dirty words", as well as anything the government considers sexually explicit or "indecent", will be banned from the Internet. The CDA, however, will not be enforceable until all appeals made against it by organizations such as the Citizens Internet Empowerment Coalition (CIEC), and the Center for Democracy and Technology (CDT), are resolved.      Ã‚  Ã‚  Ã‚   The Internet is a worldwide medium for communication and the transfer of information. It is also, theoretica... ...Internet. They also succeeded in doing this without government interference, or threatening our rights as Americans. Further, it does this in a way which keeps parents involved in their child's activities, and preserves the parental right to decide what their child is exposed to. It also ensures that the growth of the Internet is not stunted in any way.   Ã‚  Ã‚  Ã‚   If people are educated on this issue, then they will be aware of what is occurring in this conflict, so they will be ready to stand up for their rights. Anyone who is informed on the subject will not want to risk losing their rights or freedom. Further, if there are solutions which will protect children on the Internet that at the same time protect our freedom of speech and the growth of the Internet and all its information, thus appeasing both sides, it is only logical and reasonable that we follow them.

How Huck Matures in The Adventures of Huckleberry Finn Essay examples -

A French philosopher named Henry Burquen once said, 'To exist is to change, to change is to mature, to mature is to go on creating oneself endlessly.' A good example of how a person develops his or her maturity is the story of Huck in The Adventures of Huckleberry Finn by Mark Twain. In the novel, a young boy from the South travels down the Mississippi River with a runaway slave where they encounter many adventures and meet many different people. Along the way, not only does Huck mature, but he also becomes a kind and loyal person, sometimes going against the values of society. Huck's adventure down the Mississippi River is a passage into manhood because he learns to make decisions on his own as well as gain respect for Jim as a person. Huck matures throughout his adventures as he makes decisions on his own. For instance, before the trip down the Mississippi river, Tom explains to Huck how they should be like the robbers in the books, Huck responds, ?Well, if that?s the way, I?m agreed, but I don?t take no stock in it...But go ahead, I ain?t got nothing to say? (Twain 18). Earlier ...

Accomplishments of Ancient Rome

In the 3,000 years that make up the ancient history of the emergence of Western Civilization, Rome’s contributions to society include the construction of bridges, domes, and temples. The Romans had great architecture skills that have stayed with us in one form or another for thousands of years. Each construction has evolved into many different forms that are found all over the world today. Each country or civilization uses the items differently, but without the help from the Romans and Greeks transportation may have been harder to accomplish and buildings would not have the beauty they have today. Short bridges are not hard to build.They can easily be made by throwing a log across a narrow stream or river. It’s building a bridge across a wide river that can be difficult. Building a straight bridge across a wide gap can be unsafe and unsecure. The Roman’s invented a bridge in the form of an arch. This caused the bridge to be better equipped to handle heavy weight without having to put many supports in the water itself. Like all inventions, the first few arch bridges had flaws but they were worked out and now many bridges across the world have an arch like structure to them. The arch structure can also be found in historical buildings because of its beauty and uniqueness.The Romans were very proud of their accomplishment and they used it whenever they could. The Ancient Romans were the first to construct the dome. The Pantheon was an important building built in Ancient Greece that contained a dome. It is very noticeable from the exterior of the building. The dome of the Pantheon is one of the largest masonry domes every built. A heavy concrete base supports the weight, while the upper walls and dome are constructed of a lighter mix of concrete. The center of the dome has an opening which allows light and rain to enter.Many buildings and houses right here in New York have a roof with a dome shape to it. It is really popular in old Victorian ho mes. The Ancient Romans were not the first to construct temples but they contributed their own ideas to the structure. Some temples, such as the Temple of Saturn, have been rebuilt many times. Eight Ionic columns still remain on the Temple of Saturn today. Romans often didn’t include the fluting from the column shafts. Roman temples had columns and many pieces of artwork hung throughout the buildings showing Roman life just like the temples of Greece.Every building design starts off very basic and excels into something great and powerful. Each architectural design was created for some reason or another. If for some reason the Romans didn’t create the arch, dome or temples it doesn’t mean that it would never been created. They were just the first ones who needed or desired them first. I’m sure someone; somewhere would have had the idea of creating such beautiful pieces of architect. But as it stands today, we thank the Romans and Greeks for our earliest fo rms of advanced architecture.