Example research essay topic Andy Warhol 1,693 words Essay Example

Example research essay topic: Andy Warhol 1,693 words Essay The pop art movement began in London during the 1950s and then quickly spread throughout nearly all of the industrialized world. Although the artists did have some overlapping styles, pop art focuses more on the subject and less on style, which was left up to each individual artist. The main themes that is evident in all pop art revolves around modern social values. The style in which these values were portrayed varied depending on the culture and artist. Critic Barbara Rose claimed in her review of a Pop Art show that Pop Art, I wish to disagree with the assumption that pop art is an art style. It is not; these artists are linked only through their subject matter, not through stylistic similarities. This makes it possible to talk of the iconography or attitudes of Pop art, but not of Pop art as an art style, as one would speak of Baroque or Cubism. (Bondo, 1998) In America, Pop Art used the images and techniques of mass media, advertising, and popular culture, often in an ironic way to play off the social issues of popular culture. The art form developed rapidly once reaching the U.S. New York City, often viewed as the epicenter of American popular culture, fostered the growth of many of the most highly regarded pop artists, including Warhol, Rosenquist, Segal and Lichtenstein. California, namely San Fransisco was recognized as the Pop Art capital of the west coast (Bourdon, 1989, 12) The subject of Warhols work revolved around various American social issues of the mid-century. As America exited from World War II and entered the Baby Boom era, the culture had become decidedly sanitized. Some of this could be attributed to the Cold War and fear of the enemy. The flight to suburbia, mass production, conservative family values, and development of new social standards also played a major role in this Leave-it-to-Beavering of the nation. We will write a custom essay sample on Example research essay topic: Andy Warhol 1,693 words specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on Example research essay topic: Andy Warhol 1,693 words specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on Example research essay topic: Andy Warhol 1,693 words specifically for you FOR ONLY $16.38 $13.9/page Hire Writer This was also the period of time where admass culture had its beginnings. Warhol played off the irony of these issues in such works as Campbells Soup Cans and his famous Brillo Boxes (Bourdon, 1989, 34) During the 1960s, the nation began to see rapid changes. The space program was under way, the Vietnam war was in action, Kennedy was killed, racial equity became and issue and the hippie movement was at its peak; spreading its trademark ideals of free love, drugs and music. Although Warhol continued his focus on the irony of admass culture, he began to branch out into new territory. He began to print his Flowers series, which had a decidedly psychedelic flavor to them, matching the flavor of the current social scene As the 70s disco scene came to rise, Warhols work followed. Warhol himself frequented many of New York Citys hottest, most glamorous nightclubs. Studio 54, famed for its exclusivity, was one of Warhols favorites. It is at this period that Warhol became totally engulfed with creating works of other people, mostly celebrities. Ever since childhood, Warhol had been obsessed with celebrity life and fame. Some of Warhols most famous works were of celebrities. Many were chic designers such as Halson, Diane von Fursenberg, Jean Paul Gaultier and Yves Saint Laurent (Bourdon, 1989, 53) Death and disaster was also a subject that Warhol worked with, especially during the early 60s. These subjects contrasted somewhat with his others, for they seemed to be far more gruesome and vulgar. However, it was said that these were not intentionally vulgar, but again a clip from popular culture. When confronted about the morbidity, Andy said Every time you turn on the T.V. or radio, they say something like 4 million are going to die. That started it. Warhol frequently remarked about news broadcasts that projected deaths. For example, a news program may project that 50,000 people will die in alcohol related automobile accidents. To most, it seemed as if the media were relating this as a warning. To Warhol, this was a goal to be met. Also, Warhol was obsessed with the way vulgarity looses its effect after view multiple times. This is the reason that he multiplied car accident pictures many times. Many of his famous works, such as Car Crashes, Race Riots, Electric Chair, Suicides and Tuna Fish Disasters were gruesome in nature (Bourdon, 1989, 109) Another subject that seemed to permeate his work, especially his movies was sex. This was not the sex that was seen in the pornography of the time, but a more erotic and advant garde style. Sometimes, only bared flesh was seen, and other times, it was full blown intercourse. Homoerotisism was another strong theme in these movies. It wasnt just man with man or woman with woman, that would be too simple. Many of the scenes featured men as women, drag queens and asexuals. This only added to the peculiarity and erotisism. His four most famous movies revolved around sexual themes: Sleep, Blow Job, My Hustler Warhols art career began with commercial art, in where he created illustrations using a blot-line technique. The blot technique is as follows: a completed drawing is taped and hinged to a piece of Strathmore paper. The original would be inked and then blotted onto the Strathmore paper. One may wonder, why blotted drawings instead of using the originals? Andy stated, I like the style..Well, it was just that I didnt like the way I drew. I guess, we had to do an ink blot or something like that at college, and, then, I realized you can do an ink blot and do that kind of look, and, then, it would look printed somehow. (Bondo, 1998). This printed look is what made Warhol famous, adding to his admass culture themes. For a brief period, Warhol also used rubber stamps and stencils to achieve the machine made, printed look. It was in the early 60s that Warhol began to use the silk-screen method. In retrospect, the rubber stamp method he was using to repeat images over and over (a Warhol trademark) suddenly seemed to homemade he wanted something stronger that gave more of an assembly line effect. The silk-screening method was done by taking a photograph and transferring it in glue to silk, and then rolling ink across the silk so that the ink permeated only certain spots in the silk. This way, Warhol could achieve the same image, slightly different each time. The pictures were slightly faded and blurry, which resembled the way the media dulls down a story each and every time it is told. Tiny but important details Film and magazines were two other mediums used by Warhol. His films were considered underground and low budget, with strong sexual overtones. They were produced for only a brief period in his career, and were many times His magazine, however, would live on even after Warhols death. Interview was the name of the magazine that he co-produced with John Wilcock, then editor of an underground newspaper called Other Scenes. The magazine featured text and loosely edited interviews from cassette tapes. Andy often said that he started the magazine to get free tickets to all the premieres. The magazine quickly turned into a monthly review of popular culture, including moviestars, fashion, art, music, television, gossip and celebrity nightlife especially the notorious Studio 54 (Kakulani, New York Times Magazine, 1996). Another medium that Warhol used in the 70s was known as Oxidation paintings. These were large canvases created by coating them with copper paint. Warhol and his male friends would urinate on them while the paint was still damp. The uric acid and copper sulfate combined to produce a green patine. The result was work that varied widely, from Pollock-like drip paintings to misty landscapes Organization plays an important role in defining Warhols work. His use of color, treatment of masses and values and use of patterns are distinctly Warhol, separating it from that of the other Pop artists. Color was key to much of Warhols work. In fact, it was so important, that many times Warhol would produce a work without color first. Then, he would observe the work and think for days what the color should be used. Many times, color was applied by airbrush later to achieve an overlay effect. For the most part, his color schemes were bright. He also used a dot-matrix technique that spread color out by means of a tiny dot pattern. This was achieved through the silk-screening process, and added to the mass produced look (Bondo, 1998). He used appropriated and serially repeated images to achieve his machined look. This imagery arrests the eye, and speeds up the work creating his admass effect (Bourdon, 1989, 206) The shape of many of the images in his most popular works had a rounded, streamlined look to them. The values did not posses lots of detail either. This was to give them a plastic look. He was quoted as saying that these resembled club life, plastic clothes, plastic jewelry, plastic surgery, plastic emotions. (Kakulani, New York Times Magazine, 1996) The center of interest on a Warhol image is the image itself. The objects were not meant to be storytellers, as did the more classic artworks. The Warhol image was intend to confront the audience with boredom as an issue itself by making the images superficial. Usually, the objects were surrounded with space rather than pattern, emphasizing this center of interest idea (Bondo, 1998). Warhol used a detached style, in which little emotional involvement or identification is created. By use of this method, a statement is made, but does not effect the audience on a personal level. Andy Warhol was one of the twentieth centurys greatest artists. And like many artists, Warhol saw the world in a very different way. However, he was misunderstood as one who satirized American Pop culture because he did not agree with or fully understand it. Nothing could be more opposite of the truth, Warhol loved Pop culture since he was a child engrossed with the beautiful people that graced the magazine covers and movies. He became a Pop culture genius, and through his work, he became a part of it as a social commentator and visionary. And through his genius, he launched his work to become an icon of Bibliography:.

Professional Ethics Essay Example

Professional Ethics Essay Example Professional Ethics Essay Professional Ethics Essay It is a well-known fact that audit raises number of questions involving the question of ethics as it plays an important role in each organization. . Ethics evaluates actual merits, social concerns and risks associated with auditing and enterprise. Simply saying ethics can be considered acceptable behavior and can refer to morality. Actually ethics represents individual conscience, individual judgments and principles called ethical values. It is a matter of fact that ethics issues nowadays are moral standards which are enforced in society by social pressure, law and police. It seems that ethics, especially professional ethics, is misunderstood by society and people pay less attention to its role. Nevertheless if a person looks deeper, it is apparent that ethics plays a crucial role in society, because it is the basis of understanding and the source of wisdom. The paper â€Å"Developing a Code of Ethics† addresses the core ethical principles within each organization. It is suggested that professional ethics define methods to be used by auditors with decision-making process. The paper provides recommendations how to build credible and ethical culture, defines the code of ethics and its main constituents, examines the standards of professional behavior and, finally, discusses ethics in financial reporting and recordkeeping. The authors argue that because of recent scandals professional ethics should be paid more attention. Also revised sentencing guidelines provide new opportunities for all companies to develop and maintain effective ethics program. Actually, the question how to develop a code of ethics is matter of interest of managers, attorney, auditors and boards. It goes without saying that there is no single definition of code of ethics. Nevertheless, the authors define the code of ethics as â€Å"a statement of the values adopted by the company, its employees and its directors. It sets the official ‘tone at the top’ regarding expected behavior†. However, it is outlined that code of ethics shouldn’t be confused with a detailed statement of how auditors and other employees should handle dilemmas. Therefore, it is necessary to develop a handbook which will address the issues of gender discrimination at the workplace and employee discipline. Actually, the issues raised in the paper relate to the course topic â€Å"Professional Ethics†. The article touches not only theoretical aspects how to build ethical culture, the paper discusses the role of professional ethics and provides relevant recommendations how to improve personnel behavior and to increase the role of ethics within organization. The paper is a detailed guidance how to develop code of ethics paying special attention to confidentiality of information, employee empowerment and environmental stewardship. The paper is a coherent, well-organized and coercive study of a subject. Actually, all aspects of code of ethics are highlighted by the authors. Their recommendations and conclusions assist organizations in building ethical culture, because professional ethics is a core of success. It is necessary to agree with author that code of ethics shouldn’t be exhaustive; instead, it should guide both directors and employees in required direction. Apparently, the code of ethics can’t cover all possible conflict situations, managers and auditors are expected to use good judgments and to ask questions of interest. The next positive moment is that paper underlines the importance of integrity, accountability, fairness, safety and corporate citizenship. It is suggested that when working with clients, professional auditor seeks fair and open procedures and communication. The authors discuss also the upholding the values of the corporation stating that employees are expected to â€Å"deal honestly and fairly with consumers, suppliers and others having dealings with the cooperative†. However, the paper pays less attention to conflicts of interest. Conflict of interest may prevent and affect any fulfilling of duties and responsibilities in research, administration, management and instruction processes. Apparently, conflicts of interest negatively affect the working process. Emerging of a conflict is a potentially dangerous event as it provides distortion of goals, processes and outcomes.

Evaluating the impact of CSR on consumer buying behaviour, An Essay

Evaluating the impact of CSR on consumer buying behaviour, An empirical study from the UK consumer, and company perspective - Essay Example any develops and the more that it increases in size, the more does it become visible to the public’s consciousness and the more that it is expected to be responsible for its business processes and the impact of such processes on society (Daub & Ergenzinger, 2006). Corporate social responsibility is something that is focused on doing not only what is right but what is fair, while at the same time, avoiding causing harm. It can therefore be perceived as a manner with which a company regulated its activities (Moir, 2001). Corporate sustainability on the other hand, refers to the sustainable development and the ability of a company to generate performance for the long-term, in order to make sure that the company survives amidst its competition (Munilla & Miles, 2005). However, in order to make sure that corporate sustainability is possible, it is important that the company makes sure that they meet the needs and expectations of their stakeholders, while they also seek to protect, support and enhance the resources acquired from human labour and the natural resources that are needed by the entire community in future years (Strategic Direction, 2008). According to Van der Putten (2005), the stakeholder theory is one that has brought about the importance of corporate social responsibility or CSR among business organizations. Based in this theory, companies do not only have a responsibility towards the society within which they hold their operations, but also their shareholders, their employees, their consumers, their suppliers and their local communities (Vogel, 2005). In this context, it is the responsibility of any company to make sure that they are able to give something back to the entire community and the environment, both of which have helped them to become successful, or continues to contribute to their success (Bronn & Vrioni, 2001). The implementation and the continuation of corporate social responsibility among business organizations actually ‘constitutes

Criminal Law and Criminology Essay Example | Topics and Well Written Essays - 1000 words

Criminal Law and Criminology - Essay Example As may be inferred from the above stated, the subjectivism/objectivism debate effectively mirrors the existent tension between the principles of deed and equal culpability. The objectivist camp believes that criminal liability should be limited to what the person actually did, while the subjectivist camp upholds the expansion of criminal liability towards the embrace of the person's state of mind. Accordingly, the objectivist camp upholds the principle of deeds and the subjectivist camp that of equal culpability.3 The complex nature of prevailing criminal law lies it that it is neither one nor the other but seeks the embrace of both positions. This lends to several questions, all of which combine to underscore the controversies inherent in the law of criminal liability. The first of these questions pertains to the concept of mens rea. ... As per the objectivist and the subjectivist divide, there are two answers to this. The first define intention as implying that "the agent would necessarily commit an offence in carrying it out."6 The second response states that "intention should only be required for the conduct and the result elements, but not for the circumstance elements, of criminal attempts."7 (Husak, 1997). Divergent responses, reflective of the objectivism/subjectivism divide, only compound the complexities inherent in the determination of criminal liability within the context of the law of attempts. Divergent interpretations of the concept of attempt, as illustrated in the preceding paragraph, are problematic when considering the import of attempt within the context of English criminal law. As Lord Goddard maintained in Whybrow [1951]8 "intent [is] the principle ingredient of the crime." Indeed, the Criminal Attempts Act of 1981 has embodied this principle.9 As stated in the Criminal Attempts Act of 1981, "If, with intent to commit an offence to which this section applies, a person does an act which is more than merely preparatory to the commission of the offence, he is guilty of attempting to commit the offence.'10 The implication here is clear. If a person intends to rob a house but fails, he/she will be held liable for intended robbery and if he/she planned to enter a house and kill its occupants, but fails, he/she will be held guilty of attempted murder. If, on the other hand, a person enters a nursing home with the intention to rob, while knowing full well that if seen by a ny of the residents, the resultant alarm and shock could incite a heart attack culminating in death, he/she will only be held guilty of attempted robbery despite his/her knowledge of

Qualifying Exam Practice Essay Example | Topics and Well Written Essays - 2500 words

Qualifying Exam Practice - Essay Example Recently, some certain theorists made focus upon the vast stands of the opposing paradigms in the ultimate pursuance of theoretical clarity in this matter of voter legislation. Nonetheless, it now appears as if it is a renewed matter in integrating and infusing social theories towards a more known and balanced paradigm (Bell, 1992). The article of voter legislation woes, does review some of these considerations that should be highlighted by the parliament, and hence encourage further inquiry and progression into the social theory models, especially as they link to the conflict in question, and its resolution application both locally and internationally. Moreover, certain key concepts would be proposed as a continuous step toward attaining this objective in the United States of America. The initial step relates to a theoretical widening of C. Wright’s concept of sociological imagination. The second step is postulated by George Ritzer’s interest in meta-theories and it ex plains the infusion of ideas from his Major levels of social analysis model. The last one concerns the exploration of new dimensions and entails the dynamics of the social cubism model by Sean (Bew, 1990). With the fall of communism and the Cold war geo[[political order, three interlinked tendencies surface namely, the growing disempowerment of ideologies based on modern rationality, the formation of a new transnational order with an integrated financial mechanism, standards and measures of production and consumption, and the relative fall of the centralized nation state, and modern territorial sovereignty. When viewed critically, all these had an effect on the current voter identification legislation issue of the United States of America. The rise of ethno political conflicts can be shaped by both indigenous aspects and global limitations. Levels of communal linkages shape such conflicts. For ethno political conflicts, both the relations and the international system that occur amon g the nations states must be taken into consideration. In the international system, the circulation of capital, ideologies, and the use of certain crucial powers affect the rise of conflict between and within states (Bell, 1992). The importance of micro-national problems state that structures brought ethno political conflict leading to micro and macro tensions and issues of stalemates. The state can be considered to be losing some aspects of its original power of a self-identity by itself, which is a common, and a self-governing legitimacy. Social and class identities, can be replaced in some scenarios with ethnic, religious, and affiliations having territorial origin. Moreover, the new identities try to portray self-determination, appreciate group definitions and norms, and bring about ethno territorial mobilization, ethno political issues, fragmenting of the state, and not forgetting regionalism around the globe. Globalization works to enforce these local certainties and relations hips in response to the economic identity created by the world markets in the transnational order (Bew, 1992). Nowadays, research on ethno territorial politics typically examines politics, and not forgetting economic structures, so as to emphasize the competing interests of groups, or tend to utilize a psychoanalytic method to emphasize the aspect of both cultural and psychological

Two Step Extraction Of Pyrethrins From Pyrethrum

Two Step Extraction Of Pyrethrins From Pyrethrum The experimental determination of the concentration and yield of pyrethrins from chrysanthemum pyrethrum flower is usually carried out with chromatographic techniques; and accordingly, a lot of methods have been developed over the years [Wang et.al, (1997)]. These include high performance liquid chromatography (HPLC) [Todd et.al, (2003); Essig and Zhao, (2001b)], gas chromatography (GC) [Essig and Zhao, (2001a)] and supercritical fluid chromatography (SFC) [Wenclawiak and Otterbach, (1999)]. GC was chosen for convenience in this study. The first-step involves using n-hexane as solvent to extract the pyrethrins from the solid sample (grounded and unsieved with particles size of about 30 meshes), and then the second-step, a purification step involves the use of supercritical carbon dioxide as solvent to obtain the pyrethrins from the crude hexane extract (CHE). The hexane extractions (100g sample size), in a water bath at controlled temperatures and vigorous stirring, generated pyrethr ins concentrations varying from 69.85 95.50mg/ml and yields of 0.85 3.76% of the dry weight. Extraction efficiencies under several conditions were investigated and the optimum extraction condition was 400C in 4hrs. Compared with the product from the factory, several undesirable components exist in the CHE. The SFE was carried out with a self built unit (extraction vessel of 120ml) with a sample size of 40ml of CHE. Concentrations of 57.25 93.79mg/ml and yields (after the second extraction) of 0.99 2.15% were obtained; with the optimum condition being 350C at a pressure of 20MPa in 2hrs. Compared with the product from the factory, this sample contains two extra components (Tricosane and Tetracosane) also used in insect control. Key words: Solvent extraction; supercritical carbon dioxide; pyrethrins; two-step extraction; crude pyrethrins extract Introduction Pyrethrum flowers are from the Chrysanthemum genus and are known commercially as painted daisies, painted ladies, buhach, chrysanthemum cinerariaefolium, ofirmotox, insect powder, Dalmatian insect flowers, or parexan. It is believed to be recorded first in Dalmatia [Visiani, (1842-1852)]. However, others contend that its insecticidal activity was first proven by Antun Drobac (1810-1882) [Bakaric, (2005)]. Yet there are claims that it was first identified as having insecticidal properties around 1800 in Asia [Jeanne, (2009)]; and that the Crushed and powdered plants were used as insecticides by the Chinese as early as 1000 BC [Amrith, (2004)]. The flower contains about 1-2% pyrethrins by dry weight, but approximately 94% of the total yield is concentrated in the seeds [Casida and Quistad, (1995)]. The chemical structure of the active ingredients, pyrethrins I and pyrethrins II was identified in 1924 [Chandler, (1948); Coomber, (1948)]. Kenya is the worlds main producer today with more than 70% of the global supply [Jones, (1973)]. The natural active ingredients are referred to as Pyrethrins; consisting of cinerin I, jasmolin I, pyrethrin I, cinerin II, jasmolin II and pyrethrin II. The first three (chrysanthemic acid esters) are referred to as pyrethrins I (PYI), and the rest (pyrethric acid esters) as pyrethrins II (PYII) [Essig and Zhao, (2001a)]. Pyrethrins, though insoluble in water, are soluble in many organic solvents [WHO, (1975)]. They are non-volatile at ambient temperatures; non-toxic to mammals and other worm-blooded animals; highly unstable in light (photodegradable); biodegradable; but toxic to aquatic animals [Todd et.al, (2003); Chen and Casida, (1969); WHO, (1975)]. Their usage is mainly in biological crop protection; domestic insecticides [Gnadinger, (1936)]; and the formulations of synthetic pyrethroids [Todd et.al, (2003)]. Although pyrethrins are soluble in a number of organic solvents (benzene, hexane, petroleum ether, alcohol, acetone, meth anol, chlorinated hydrocarbons, etc) other considerations (practical, economic and environmental concerns) limit the usage. These considerations reduce the choices to just few. One of the qualities of Hexane in extracting pyrethrins is its ability to effectively dissolve the active ingredients minus contaminants. Another is that its removal from the concrete is achieved at lower temperatures; limiting degradation due to prolonged heating. Again, its low boiling point is a needed quality and it can be recycled, reducing the weight of the concrete. Above all, it is inexpensive, considered environmentally friendly, less toxic, non-corrosive, and non-reactive; traits which make it the dominant solvent adopted, especially for processing plant (biological) materials (products) which are often thermally labile, lipophilic, and non-volatile and are required to be kept and processed at around room temperatures. Carbon dioxide (CO2) has a critical temperature of 31oC which makes it particular ly an attractive medium for these kinds of tasks. Though other supercritical fluids (SCFs) show critical temperatures in this critical state and can be adapted as solvents, they are often difficult to handle and obtain in pure state, may be toxic, explosive or ecologically unsafe. Supercritical carbon dioxide (Sc-CO2) is by far, the most extensively used due to its non-toxic, inert and non-flammable nature. It is also natural, inexpensive, plentiful, non-toxic and inflammable and generally environmentally accepted [Schneider et.al, (1980)]. Its most important properties are enhanced density, viscosity, diffusivity, heat capacity and thermal conductivity. Higher densities contribute to greater dissolution of compounds while low viscosities enable easy penetration into samples and facilitation of flow of extracted (targeted) molecules from the source materials with fewer hindrances [Dunford et.al, (2003)]. Diffusivity offers easy and faster transport through samples; hence offers bett er extraction strengths; and dissolved ingredients are also easily separated from the supercritical solvent by drop in pressure [Fattori et.al, (1988)]. Sc-CO2, for the above and many reasons used as solvent in extraction saves both time and money while retaining overall extraction precision and accuracy with high purity and healthy products that are of excellent quality [Raventos et.al, (2002); Mohamed and Mansoori, (2002)]. Expectedly, a lot of research is now focused on the extractions of plant materials with supercritical carbon dioxide due primarily to the global growing solvent (organic) regulations and more importantly, the economic benefits (in terms of low operating temperatures; faster extractions and easier purifications, and of course better product quality). Stahl and Schutz [Stahl and Schutz, (1980)] extracted pyrethrins with CO2 and proposed that in the 20 °C to 40  Ã‚ °C temperature range decomposition (usually associated with pyrethrins extraction) does not occu r. Sims patented in the US, an extraction of pyrethrins using liquid carbon dioxide [Sims, (1981)] and Wynn and others patented using Sc-CO2 [Wynn et al. (1995)]. Wenclawiak and coworkers compared extracts obtained with ultrasonic (USE) and Soxhlet extractions (SEX); with hexane and Sc-CO2 extractions (SCE) and reported that direct extraction with SCE gave better pyrethrins content [Wenclawiak et.al, (1995)]. 2. 0. Experimental 2.1. Materials and Chemicals Grounded chrysanthemum (light green with a characteristic smell) sample and two pyrethrum concretes (yellow) were obtained from Yunnan Juxiang Natural Plant Products Company in China. The pyrethrins content of the concretes was claimed to be 50.0% (29.50% PYI and 20.50% PYII) and 85.15% (46.33% PYI and 38.82% PYII). Six individual standard solutions (using standard addition method) were prepared (from the 85.15% PY concrete-higher content, less impurities) for standardization of the analytical method. Analytical grade hexane (97.0%) and Ethanol (99.7%) were purchased from Sinopharm Chemical Reagent Co. Ltd in China, and used directly without any pre-treatment. CO2 (99.0 %) gas was supplied by Xin Hongli Gas Company also in China. 2.2. Experiments Three different experiments were performed: To establish the standard/calibration curves for determining the components, To implement hexane extraction and determine the yield of total PY in the grounded sample, and To implement SFE and determine the yield of total PY in the CHE. 2.3. Establishing Standard Curves The GC (Agilent) conditions used for establishing the standard curves are as follows: split injector with 20:1 split ratio at 2500C; Nitrogen as carrier gas at 1.6mL/min  ¬Ã¢â‚¬Å¡ow rate; injection volume of 0.1  µL; temperature program started at 1800C, kept for 11 minutes, heated at 100C/ min to 2000C, kept for 8 minutes, heated to 210 0C at 100C/min, kept for 18 minutes, then heated to 2450C at 30 0C/min, maintained for 4 minutes; FID detector; HP-5 Column, 30 mm 0.32 mm id., 0.25  µm  ¬Ã‚ lm thickness. This column was chosen because it gives the best resolution, identi ¬Ã‚ cation and quanti ¬Ã‚ cation for products containing OH and C=O [Rosana, (2003)]. 2g (85.15% concrete obtained from the company) of the extract was transferred into a 100mL flask containing 10mL ethanol, and then made up to the final volume of with ethanol and mixed well. Six aliquots (1mL, 2mL, 4mL, 8mL, 16mL and 32mL) of this solution were transferred into a 50mL flask each and diluted with et hanol again to the mark. We then calculated the concentrations of the PY in each aliquot, considering the percentage of each group (PYI and PYII) in the sample provided (Table A1 in the Appendix), injected (with a micro syringe) 0.1 µL of each solution into the GC after filtering (0.45-ÃŽ ¼m membrane filter) and recorded the elution times and corresponding peak areas (Table A2); subsequently, established the standard curves to express the relationship between the areas produced by the GC and the concentrations (Figure 2). 2.4. Hexane Extraction We extracted pyrethrins (from 100g of grounded sample of particle size of about 30mesh) with hexane in a water bath (YUHUA, DF-101S) in batches at different temperatures (35oC, 40 oC, 45 oC, 50 oC, 60 oC and 70 oC) and times (3hrs, 4hrs, 5hrs, 6hrs and 7hrs) in a 1000mL round-bottom flask, installed with a condenser. Agitation was achieved by stirring vigorously with three big size magnetic stirrers at a speed of 20rpm. The hexane was then removed from the pyrethrin concrete with a rotary evapourator (YUHUA, RE-2000B) at a temperature of 35 oC at a speed of 185rpm to obtain concentrated Crude Hexane Extract (CHE). Each concentrated sample was thereafter, filtered (0.45 µm) and 0.1 µL analyzed (Tables A3). This method has the advantage that the solvent is repeatedly recycled and temperature can be controlled. It offers a light coloured product with high recovery rate of pyrethrins; however, not only the desired components are extracted (Figure 3). Other soluble and hydrophobic sub stances (waxes and pigments) are also extracted [Kiriamiti et al, (2003)]. The solvent is removed by vacuum at lower temperature and the waxy thick mass left is the concrete; composed of essential oils and other oil soluble (lipophilic) materials. 3.0. Results and Discussion 3.1. Extract The extracts (CHE) contain pigments, fixed oils and waxes whose colour is deep yellow with characteristic smell. It also contains several undesired components (Figure 3) compared with the pure sample from the factory (Figure 1). 3.2. Effect of Extraction Temperature Temperature has long been reported to be a crucial factor in the extraction of natural pyrethrins [Atkinson et.al, (2004)]. Pyrethrins are sensitive to temperature (thermo labile) and are therefore, unanimously reported to degrade above 40oC [Stahl and Schuzt, (1980); Gourdon and Romdhane, (2002); Wynn et al, (1994)]. We investigated the effect of different extraction temperatures (40oC, 50oC, 60oC and 70oC) in fixed extraction times (5 hr gave better results than 6hr and 7hr). Our results conform to the reports (refer to Figure 4 and Table A3); the best yield (1.42) and PYI: PYII ratio (4.75) is at 40oC (but the best PYII yield-0.33 is at 70oC). This suggests that targeted components are extracted effectively at this temperature (40oC), above which two problems occur (separately or simultaneously): one is the extraction of more undesirable components at the expense of pyrethrins and the other is the decomposition of pyrethrins to form iso-pyrethrins [Stahl and Schuzt, (1980); Stahl, (1998); Gourdon and Romdhane, (2002); Wynn et.al, (1994)] thereby reducing the yield as seen. 3.3. Effect of Stirring We compared the effect of two stirring methods on extraction yield: the first with one magnetic stirrer and the second with three magnetic stirrers. The results are shown in Table A4, confirming that stirring improves extraction yield by facilitating the dissolution of the active ingredients and the effective distribution of heat. The extractions (at 40oC in 5hr) were repeated severally to ensure reproducibility and accuracy. 3.4. Effect of Extraction Time We further investigated the effect of extraction time by fixing the extraction temperature at 40oC with three magnetic stirrers; to establish the optimum extraction time (our initial time parameters were 5hr, 6hr and 7hr in which 5hr was the best). From Figure 5, the extraction yield increases steadily from 3hr to a peak at 4hr (see data in Table A5). Within this range, more desired components are extracted but after 4hr the yield decreases indicating that with prolonged time, even at the safest extraction temperature (40oC), less and less desired components are extracted and/or they decompose resulting in the decrease in yield. The drop in yield is consistent from 4hr (3.76%) to 6hr (2.15%). This implies that the optimum time (within the times investigated) is not 5hr as initially expected but rather 4hr. However, the ratio of PYI: PYII is best in 6hr (5.14). From 3hr to 4hr, the yield for both PYI and PYII appreciated but the increment in PYI (0.74) is greater than that of PYII (0. 38) hence the drop in the ratio. Between 4hr and 5hr, there is decrease in both PYI and PYII yields. Again, the decrease in PYI (0.98) is greater than that of PYII (0.49) accounting for the drop in ratio. The same reason accounts for the drop in ratio from 5hr to 6hr. 3.5. Effect of Concentrating CHE The effect of concentrating the CHE, on both PYI and PYII yield was analyzed (Table A6). Even though the concentrating temperature (35oC) was below the temperature above which PY degrades (40oC), there was loss in PY yield indicating degradation. This in our view may be due to the exposure of the pyrethrins directly to heat. As more hexane is evapourated, pyrethrins which hitherto, were locked in the solid sample matrix; surrounded by hexane and as such shielded from direct heat, is now in direct contact with the heat; and since they are sensitive to heat, decomposition is inevitable. However, the decomposition is small and negligible (about 2.25mg/ml which is about 0.41% of the total yield) due to perhaps the short concentrating time (about 30 min). 4.0. Supercritical Fluid Extraction (SFE) The CHE is too thick (viscous) to be used directly, coupled with the presents of undesirable components (waxes and pigments). A further treatment, usually with another solvent that only dissolve the desired compounds from the concrete is necessary. Different from other works, this study carried out SFE on the CHE as a purification step. We looked at the effect of time (hr), temperature (0C) and pressure (MPa) on extraction quality and yield. We have not studied the effect of particle size and pre-treatment; for information on this area, see the works of Kiriamiti and others [Kiriamiti et al, (2002)]. 4.1. Sample We concentrated the CHE in a rotary evapourator (from 500ml to 40ml at 185rpm in 30 minutes) for the SFE. 4.2. Extraction Process At the beginning of the extraction (Figure 6), all the check valves are closed except valve #2. This allows the CO2 gas into the compressor #4 (OLSB by Zheng Zhou Co. LTD, China) to be compressed, and the pressure gauges are allowed to attain equilibrium at a set pressure (10, 15 and 20 MPa). Valve #5 is then opened and the compressed fluid (Sc-CO2) is fed into the bottom of the extraction vessel #7 (120ml capacity) for up flow extraction configuration, containing the CHE (40ml) and metal fillings to facilitate effective contacting (increase internal mass transfer); which had earlier been heated to a set temperature (350C, 370C and 390C) and allowed to attain constant temperature with the help of the water bath #6. An appreciable time is allowed (5-10mins) for the total and complete dissolution of the crude extract and then valve #8 is opened and maintained until the pressure is in equilibrium again. The pressure reducing valve #9 is opened finally to collect the pyrethrins in the fl ask #10. A mass flow meter helps to determine the flow rate (1.5L/min). The extraction process is run and stopped at set times (1hr, 2hr and 3hr) and the extracts analyzed with the results tabulated (Table A8). The Metal fillings after each run were washed (10ml or 5ml of Hexane) and collected as residues to check for complete extraction. 5.0. Results and Discussion 5.1. Extracts The extracts did not contain visible pigments as was seen in the CHE. The colour was also different; light yellow to orange but the smell was similar. It also contained two extra components (Figure 10) which was found (by GC mass spectrometry) to be Tricosane (Peak 6) and Tetracosane (Peak 7). This was as a result of comparison with the pure sample from the factory (Figure 1). We compared the yield of the extracts after solvent extraction, concentrating the CHE and the SFE and noted that there was difference. The yield from the SFE was less due possibly, to the relatively high pressures used. Separation of the Sc-CO2 and the product is achieved by a drop in pressure. These high pressures have the tendency of causing the products to remain in the BPR or along the pipe (between the BPR and the flask in Figure 6) due to clotting as a result of the pressure drop; in spite of our use of heating tapes to minimize this effect. This is confirmed by the value of the yield in the residue (0.05%) which is far less compared to the difference between the concentrated sample yield (3.30%) and that of the SFE (2.15%, see Table A10). 5.2. Effect of Pressure According to Kiriamiti and others, the quantity of pyrethrins extracted decreases with decreasing pressure due to (i) the effect of density on the solubility of pyrethrins, (ii) the slightly high density of CO2, (iii) the moderate variation in density with pressure, and (iv) the very low undesirable extracted products [Kiriamiti et al, (2002)]. Our results conclusively conform to this (Table A7). The best extraction pressure was at 20MPa (at 350C and 2hrs). The concentration of PY also increases within this pressure range (from 81.34mg/ml 93.79mg/ml). Similar phenomenon was observed for both 1hr and 3hrs, indicating that more pyrethrins were extracted than the undesirable components within this pressure range (Figure 7). 5.3. Effect of Extraction Time The quantity of pyrethrins extracted decreases with extraction time at higher temperatures (above 400C), explaining that either pyrethrins decompose at these elevated temperatures or more undesirables are extracted instead. From Table A8, the yield and concentration of PY increase from 1hr to a maximum in 2hr (1.35% 2.15% and 90.42mg/ml 93.79mg/ml at 350C and 20MPa). Both however decrease in 3hr (1.24% and 82.30mg/ml, Figure 8). This implies that pyrethrins were extracted faster than the undesirables from 1 to 2hr but as the extraction proceeds, more undesirables were then extracted at the expense of the pyrethrins or which decompose. Therefore, prolonged extraction time rather favours the extraction of undesirables or promotes decomposition of pyrethrins. 5.4. Effect of Temperature Pyrethrins are thermo labile and therefore require being processed at low temperatures. Therefore, high extraction temperature does not only degrade the pyrethrins but also favours the extraction of undesirables (Figure 9). Within the temperature range we investigated, the best yield was at 350C (Table A9). 6. 0. Conclusions Pyrethrins are usually purified with organic solvents (ethanol, methanol, acetone, acetonitrile, petroleum ether etc) or their mixtures [Kasaj et.al, (1999); Henry et.al, (1999); Duan et.al, (2006)] which are generally expensive, flammable and explosive and above all, face strict legislative controls [Patrick, (2003)]. Alternatively, carbon dioxide is used to refining and purification. Sims proposed the use of liquid carbon dioxide [Sims, (1981)]. Similar to our method, Kiriamiti and others reported the extraction of pyrethrins from crude hexane extract (CHE) from batch extraction experiment using carbon dioxide [Kiriamiti et.al, (2003)] but with different extracting conditions and analysis method (HPLC). It is worth noting that our set up is very simple and less expensive coupled with the fact that our sample, after the SFE, contains two extra components (Tricosane and Tetracosane) not reported so far as part of the purification step. These components are not hazardous [Directive 67 /548/EEC] and have similar characteristics (may cause respiratory and digestive irritations), uses (as insecticides and biopesticides) and effects (they may not be detrimental to the insects but they certainly disrupt their behaviuor patterns and flushes them out for the more deadly pyrethrins I) as pyrethrins II [Chemcas.org; Chemnet.com; PPDB, (2011); Wylie, (1972); Lewis et.al, (1975)]. We developed a simple but efficient two-step procedure for the extraction of pyrethrins from chrysanthemum (pyrethrum flowers) and investigated the effect of various operating parameters on concentration and extraction yield. Based on the experimental results, we conclude that the two-step extraction of pyrethrins (first with hexane in a water bath and second with SC-CO2 as a purification step) is feasible and effective; the optimum extraction condition for high pyrethrins yield (3.76%) for the n-hexane extraction was 400C in 4hr; that vigorous stirring facilitated this; and that it is possible to achieve extraction yield of 3% or even more envisaged by Casida and Quistad. To our knowledge, this is the first time such a high recovery of pyrethrins is reported. A number of reasons may be attributed to this high recovery: i) extraction procedure, ii) choice of solvent, iii) vigorous stirring and above all, vi) the type of sample used. We further conclude that for the SFE (2.15% and 93.79mg/ml) the optimum conditions were 350C, at pressure of 20MPa in 2hr. 7.0. References Amrith S. Gunasekara, (2004): Environmental Fate of Pyrethrins, Environmental Monitoring Branch, Department of Pesticide Regulation, 1001 I Street, Sacramento, CA 95812 Atkinson B. L, Blackman A. J, and Faber H, (2004): The degradation of the natural pyrethrins in crop storage, J. Agric. Food Chem. 52, 280-28 Bakaric P, (2005): BuhaÄ  prirodni insekticid, Gospodarski list 17: 41-45 Casida J. E and Quistad G. B, (1995): Pyrethrum Flowers: Production, Chemistry, Toxicology, and Uses, Oxford University Press, New York Chandler S. E, (1948): The Origin and Early History of the Production of Pyrethrum in Kenya, Pyrethrum Post 1 (1): 10-13 Chen Y-L, and Casida J. E, (1969): Photodecomposition of Pyrethrin I, Allethrin, Phthalthrin, and Dimethrin, J. Agr. Food Chem. 17: 208-215 Coomber H. E, (1948): The Chemical Evaluation of Pyrethrum Flowers, Pyrethrum Post 1 (1): 16-19 Directive 67/548/EEC: The Dangerous Substances Directive (as amended) is one of the main European Union laws concerning chemical safety. Duan Wei, Zhengguo Li, Guomin Wang, Yingwu Yang, Yingguo Li and Yuxian Xia, (2006): Separation and purification of Natural pyrethrins by reversed phase high performance liquid chromatography, Chin. J. of Anal. Chem., vol.34, is.12, pp 1776-1779 Dunford N. T, Teel J. A and King J. W, (2003): A Continuous Counter Current Supercritical Fluid Deacidification Process for Phytosterol Ester Fortification in Rice Bran Oil, Food Research International 36, 175-181 Essig K and Zhao Z, (2001b): Method Development and Validation of a High-Performance Liquid Chromatographic Method for Pyrethrum Extract, J Chromatogr Sci 39 (4): 473-480 (8) Essig K and Zhao Z. J, (2001a): Preparation and characterization of a Pyrethrum extract standard. LC/GC 19(7): 722-730 Fattori M, Bulley N. R, and Meisen A, (1988): Carbon Dioxide Extraction of Canola See: Oil Solubility and Effect of Seed Treatment. J. A. O. C. S. 65, 968-974 Gnadinger C. B, (1936): Pyrethrum Flowers. 2nd Ed. McLaughlin, Gormley, King, Minneapolis, Minnesota Gourdon C and Romdhane M, (2002): Investigation in Solid-Liquid Extraction: Influence of Ultrasound, Chemical Engineering Journal 87, 11-19 Jeanne Roberts, (2009)  : Insecticide Treated Mosquito Nets and Malaria Prevention: Weighing the Benefits, Naming the Benefactors at www.celsia.com Jones G. D. G, (1973): Pyrethrum Production, In Pyrethrum; The Natural Insecticide, J. E. Casida (Eds.), Academic Press. New York, NY, 17-21 Kasaj D, A. Rieder, L. Krenn and B. Kopp, (1999): Separation and Quantitative Analysis of Natural Pyrethrins by High-Performance Liquid Chromatography, Chromatographia Vol. 50, No. 9/10 Kiriamiti H. K, Camy S, Gourdon C and Condoret J.S, (2003): Pyrethrin Extraction from Pyrethrum Flower using Carbon Dioxide, J. Supercrit. Fluids, 26, 193-200 Lewis W. J, Richard L. Jones, Donald A. Nordlund and Gross H.R JR, (1975): Kairomones and their use for the management of entomophagous insects: II Mechanisms causing increase in rate of parasitisation by Trichogramma spp, J. Chem. Ecol., vol. 1, No. 3, pp 349-360 Mohamed R. S and Mansoori G. A, (2002): The Use of Supercritical Fluid Extraction Technology in Food Processing, Featured Article, Food Technology Magazine, June, The World Markets Research Centre, London, UK Patrick Pelerin, (2003): Comparing Extraction by Traditional Solvents with Supercritical Extraction from Economic and Environmental Standpoint, Proceedings of the 6th International Symposium on Supercritical Fluids, TOME 1 Raventos M, Duarte S, and Alarcà ³n R, (2002): Application and Possibilities of Supercritical CO2 Extraction in Food Processing Industry: An Overview, Food Sci. Technology International, 8 (5), 269-284 Rosana V, (2004). 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Direct Determination of Pyrethrins in Pyrethrum Extracts by Reversed-Phase High Performance Liquid Chromatography with Diode-Array Detection. J. of Chrom. 766, 277-281 Wenclawiak B. W and Otterbach A, (1999). Supercritical Fluid Extraction Kinetics of Pyrethrins from Flowers and Allethrin from Paper Strips. J. Anal. Chem. 365 8, 472-474 Wenclawiak B. W, Krappe M and Otterbach A, (1995): In Situ Transesterification of the Natural Pyrethrins, J. of chrom. A, 785, 263-267 World Health Organization, (1975): Data Sheet on Pesticides No. 11, Pyrethrins (www.inchem.org/documents/pds/pds/pest11_e.htm) Wynn H. T. P, Cheng-Chin C, Tien-Tsu S, Fong L, and Ming-Ren S. F, (1995): Preparative Supercritical Fluid Extraction of Pyrethrins I and II from Pyrethrum Flower; Talanta 42, 1745-1749

Toni Morrisons Sula - The Provinciality of Sulas Characters :: Sula Essays

The Provinciality of Sula's Character's In her review of Toni Morrison's novel, Sula, Sara Blackburn complains that the setting and characters "seem somehow frozen, stylized"(1). While Blackburn talks favorably about Morrison's past novels (The Bluest Eye in particular), she is of the opinion that Sula is less successful because the characters are confined to one location and one mode of thought. Morrison hasn't endowed her people with life beyond their place and function in the novel, and we can't imagine their surviving outside the tiny community where they carry on their separate lives (1). While I agree with Blackburn that the characters remain inside the confines of the Bottom and the way of life there, I disagree with her that the characters are nothing more than their place and function in the novel. After reading this review, I began to think about other famous authors and novels and I realized that most stay within a certain setting and way of life. Morrison is not writing her characters as flat by making them a product of their environment and upbringing; she is simply mirroring the reality of life and human nature. I also disagree with Blackburn that the character of Sula is the exception in the novel. She too is simply a meshing of her surroundings and the people who raised her and whom she came into contact with. Had Sula not been raised by a mother prone to taking other women's husbands into storage closets, she would not have slept with her best friend's husband and then act as if she had done nothing wrong. Morrison say's the following in the novel about ho w Sula became the woman she was: Eva's arrogance and Hannah's self-indulgence merged in her and, with a twist that was all her own imagination, she lived out her days exploring her own thoughts and emotions, giving them full reign, feeling no obligation to please anybody unless their pleasure pleasedher (118). I also disagree when Blackburn says that Sula is a novel "whose long-range impact doesn't sustain the intensity of its first reading"(2). How can that be true when the character's actions are never those that the reader expects. The reader is forced to wonder why about so many different situation in the novel, that it sticks with them way after they've put down the book. How could Eva justify burning alive her own son?