of the American Chemical Society
We eat food for basic nourishment but also for the enjoyment that it gives us. One big part of that enjoyment is the flavor of the food. Many people will try a product once, but if it doesn't taste good, they will not try it again. Flavor chemistry is a fascinating area of research covering the analysis of what contributes to the flavor of the products that we eat to development of flavors that will work in a wide variety of products to the quest for new and unique flavors. As an example of what contributes to the flavor of a product, analytical chemists have identified over 800 volatile compounds in roasted coffee. The question is which of these are most important to creating a good coffee flavor. In terms of development, consumers want convenience and quality. Flavors tend to be unstable so there is a constant challenge to find ways to protect flavors as they go through heating, cooling, packaging and storage. Finally, there is always the search for that new or unique flavor that will be the next big blockbuster flavor--the next blue raspberry. An overview of flavor chemistry and current areas of research will be presented.
Audience Level Specialists (highly trained), Chemists, Students,
During his boyhood in Shanghai, China, R. Liu often heard the statement: "Dogs can see ghosts!" Now after more than three decades of research in Vitamin A and visual pigments, he asked himself whether there is scientific basis that "dogs can see ghosts". Preparing to answer this question in this presentation, he will first review the important development in the chemistry of vision in recent decades with particular emphasis on the work carried out at the University of Hawaii. Topics covered will be: stereospecificity of the binding site of rhodopsin, the probing of specific protein-substrate interactions (in rhodopsin) through F-NMR spectroscopy, the specific mode of photoreaction that triggers the visual process and the unusually high photosensitivity of rhodopsin.
Our society has diverse energy choices. While availability and cost are concerns; safety, environmental impact, and infrastructure must also be considered. Alternative fuels, fuel cells, electric power, and advanced conventional technologies such as alternative fuels for diesel will all be compared in order to better understand the technical challenges and political consequences.
Coal is the most prevalent fossil fuel in the U.S. (and in the world) with a resource of some 6500 quads as compared with oil at 180 quads and gas at 210 quads (and fissionable uranium oxide at about 180 quads). In the U.S. in 2000, 3.02 quadrillion watt-hours of electric energy were produced. Of this electric generation, coal fueled 56.3%, oil fueled 2.4%, gas fueled 9.6%, hydro fueled 8.4%, and nuclear energy fueled 23.4%.Thus coal and nuclear account for almost 80% of the electricity generated in the U.S. With coal so prevalent clean coal technologies are important both economically and environmentally. Coal refining is one such technology. It is similar to oil refining in that the coal is hydrodisproportionated to produce a slate of products including, char (about 40%), an "oil" (about 35%) and naphtha, BTX, sulfur and ammonia. Since about 85% of the sulfur and 70% of the nitrogen originally in the coal are recovered as saleable products, the resultant char may be burned without pollution controls. As with an oil refinery the coal refinery may be tweaked to change the various product yields. It also has three end-use configurations, all three of which can produce very high purity diesel fuel. One configuration, which has unusually high returns (IRRs), is coupling the refinery with an Integrated Gasifier Combined Cycle (IGCC) electricity generator. The technology will be discussed including energy and material balances, flow charts and schematics, and the three end-use configurations.
Audience Level: Specialists (highly trained), Chemists, Students
The leafcutter ants (Hymenoptera, Formicidae, Attini) are classed as agricultural pests throughout the tropical Americas, both because of the massive amount of leaf material that they harvest and their special fondness for agriculturally important plants. Colonies whose foraging is restricted to areas of native forest encounter a great variety of potential host plants, but, while the ants are considered polyphagous, they are quite specific in their preferences for some plant species and dislike of others. We have been investigating avoided plants for the presence of natural chemical defenses against this insect. From the leaves of unpalatable plants, we have isolated a number of compounds that function as ant repellents. Representative structures will be presented to illustrate modern techniques for determining the structures of natural products (e.g. 2-D NMR and chemical synthesis). Some speculation on the basis of this ant-repellent activity also will be offered. Application of the strategies developed from studies with leafcutter ants to investigation of other types of insect-plant interactions may be presented as well.
Audience Level: Specialists (highly trained), Chemists, Students
This is a time of powerful forward momentum for engineering and applied science and for chemistry, physics and mathematics. Ours is an era marked by sophisticated, rapidly changing, all-pervasive technology, and by physical sciences and applied mathematics that universally transform the way we live and work. At the same time, we find ourselves in global environments that demand local attention. It has been said that these are the best of times and perhaps they are, but the pessimist fears that truth. Our greatest responsibility to successors is to make them more aware of the context of their actions. How we do that, why it is important, and who should care are questions this scientist hopes to answer in words and pictures. The answers lie at the very core of the undergraduate curriculum.
Audience Level: Specialists (highly trained), Chemists, Students
For the average person, fluorine chemistry means fluorocarbons, which are often cited as the cause of the problems of our protective ozone layer. The lecture gives a general view on why fluorine chemistry forms a special branch of chemistry when the other halogen compounds are regular parts of organic and inorganic chemistry. It describes the general methods for the preparation of fluorine compounds while providing an explanation for their unique properties. Various examples will be given to show the uses for these compounds.
Amber is an extraordinary natural material. It has been know to, and prized by, humans since at least the Neolithic period and remains admired and valued in virtually every human culture today. Fossil insects entrapped in amber are preserved in life-like detail for tens to hundreds of millions of years and control of the amber trade has influenced the course of human history perhaps more than any other organic material prior to fossil fuels.
Amber is the fossil form of the resins that are commonly produced by many plants. Most resins are comprised of mixtures of terpenoids that polymerize to form of complex copolymers. The hardened masses that result are highly resistant to many of the processes which break down most other types of biomass, and undergo only subtle structural changes in response to heat and pressure under geologic conditions. Because of this, ambers can preserve details of their original molecular structure over great periods of time - often in excess of 100 million years.
Ambers are of interest to scientists working in a variety of disciplines, including archaeology, chemistry, and geology (among others). This presentation will describe the geochemistry of amber, including case studies of the use of amber as a geochemical marker of vegetation that grew in the remote past, and archaeological studies related to investigation of the legend of El Dorado.
Beginning in the fall of 1992, Wright State began offering an experimental alternative general chemistry sequence containing the core material identified by the General Chemistry Task Force of the ACS Division of Chemical Education, organized on a framework of meaningful uses or occurrences of chemistry. The course is backwards in that it starts with organic chemistry, which is usually taught at the end of the year if covered at all. It is inside-out as it is organized around applications and occurrences of chemistry and brings in concepts as needed instead of viceversa. It is upside-down as topics are chosen based on the interest or usefulness to all students instead of only training for chemistry majors. Emphasis is on educating students in chemistry instead of only training them to do calculations. The three major themes are, in the order of presentation, organic and biological chemistry, materials, and energy. Only those principles and concepts that are necessary to present these topics are developed and only as they become necessary. I will share the successes and failures; the difficulties encountered; some unexpected benefits of the revised sequencing; the administrative problems presented; some student participation that developed; and, perhaps most important, the students' reaction and evaluations.
4:30 PM, Monday, March 28, 2005
James N. BeMiller
Purdue University
" Polysaccharides in Nature and Industry (Polysaccharides in Our Lives)"
About 90 percent of all biomass is carbohydrate, and more than 90 percent of all carbohydrates are in the form of polymers called polysaccharides. The commercial water-soluble or -dispersable polysaccharides, commonly called gums, are used in a variety of industries from petroleum production to foods. Preparation from plants, seaweeds, and bacteria; structures and properties that make them useful in diverse applications (e.g., oil well drilling muds, adhesives, textile sizing agents, food gelling agents, etc.); and uses of a representative sample will be presented in a way that is understandable by, and interesting to, both scientists and nonscientists.
Monday, Nov. 15, 2004, 4:30 G-3 Schrenk Hall
Dr. Terry Brewer
Brewer Science
"Elements of Leadership for Scientists"
Focus on various elements and characteristics that need to be learned in
order to assume a leadership position - whether leading others or
oneself. Topics of discussion will include core competencies,
leadership models and the dimensions of success.
NOTE: Location is in the UMR Electrical Engineering Building room G-31, 4:15pm, with refreshments.
NOTE: Location is in the UMR Electrical Engineering Building room G-31, 4:15pm, with refreshments.