Headspace Analysis Essay Example | Topics and Well Written Essays - 750 words

Headspace Analysis - Essay Example This technique has been used to identify spoiled food, fragrances from botanical material, the determination of plasticizers in plastics and for forensic samples involving arson snuff. Its main component, nicotine is habit forming and other compounds produced by pyrolysis during smoking are carcinogenic and can cause a number of other health problems. Tobacco is an extremely valuable export in the United States despite the health concern, and its quality is carefully monitored. Tobacco can be flue cured, air cured, fire cured or sun cured, but the quality of the product can often be monitored by analyzing the vapors in the head space above the tobacco. The head space over tobacco can be sampled and analyzed using a Solid Phase Micro Extraction (SPME) technique. Diesel is similar in chemical composition to kerosene and heating oil in that it is composed of aliphatic hydrocarbons that are obtained from the fractional distillation of crude oil. Diesel has a higher boiling point fraction and the distillation range is greater than that of kerosene and heating oil being composed of essentially C10 to C25 aliphatic hydrocarbons. The use of these extremely sensitive laboratory techniques must be made carefully because of the consequence of obtaining a false positive result. The possibility of the accidental contamination of a sample through poor sampling and laboratory techniques needs to be minimized. The research has shown the sample containers can be cleaned before use and should be sealed before transport to the fire scene. Samples should then be delivered to the laboratory and analysed promptly. The laboratory equipment should be cleaned before use and blank samples analysed regularly to check for any possible contamination. The extraction equipment can be cleaned by washing with acetone and heating the gas transfer lines with a Bunsen burner. The interpretation of the chromatograms must be made carefully using a library of chromatograms composed of the common accelerants, industrial solvents, common household materials, The analysis of numerous burnt synthetic materials was found to be distinct from the common accelerants. The common accelerants were found to change during evaporation making it sometimes difficult to distinguish between those composed entirely of entirely of an aliphatic hydrocarbon fraction. Ethanol could not be detected in fire debris using charcoal absorption extraction techniques and alternative analytical techniques were needed. The background level of accelerants in the environment is dependent of the history of the sample material. Traces of petrol and aliphatic hydrocarbons were found in soil from a motor wrecking yard, however, no traces were found in numerous car flooring materials indicating none would be expected from a domestic environment. Gas odourants could also be detected using the same equipment as that used for fie debris analysis which would assist the investigation of suspected gas explosions. References: 1. Evans, J.S. "Arson in Australia. Dimensions of the Problem and

Art and design Essay Example | Topics and Well Written Essays - 1250 words

Art and design - Essay Example The Harlem renaissance art borrowed heavily from post impressionism. The African American community came to understand that it was their time to flourish as human beings. This is usually referred to as the period of enlightenment for the African American artists and the people. This essay seeks to discuss the Harlem renaissance basing on the two prominent figures, Richmond Barthe and Aaron Douglas. It compares and contrasts their early life, their education and their contribution in the Harlem renaissance. Richmond Barthe was born in bay St Louis, Mississippi. This was on January 28, 1901. His father was sr. Richmond Barthe and his mother Marie clementine Robateau. His mother sewed to support the family and his father died when he was only a year old. His mother later remarried to Barthe’s godfather, William franklin. William had no stable job and he worked odd jobs to sustain the family. This included being the icemen to the local community. Interestingly, Barthe’s interest in art developed at a very tender age. Barthe himself mentions that his mother would keep him calm through giving him a piece of paper to draw on. This would allow the mother enough time to run the house errands (Schulman & Peter, 2009 p123). At the age of six years, Barthe began to paint after the master the mum sewed for gave him a set of water colors. At this age, Barthe could draw well. When Barthe was a teenager, his art was overdeveloped for his age. Most of his paintings captured his father’s ice customers and his mother’s sewing customers. Luckily as he helped his father in delivering ice during the summer, one of the customers noticed the hardship and helped him get a job in New Orleans (Black, 2009 p234). This family encouraged his art and as he worked as a houseboy, Barthe furthered his talent in art. It was around this time that Barthe met Lyle Saxon. This was a writer for the New