Comparison of epifluorescent viable bacterial count methods

Two methods, the 2-(4-Iodophenyl) 3-(4-nitrophenyl) 5-phenyltetrazolium chloride (INT) method and the direct viable count (DVC), were tested and compared for their efficiency for the determination of the viability of bacterial populations. Use of the INT method results in the formation of a dark spot within each respiring cell. The DVC method results in elongation or swelling of growing cells that are rendered incapable of cell division. Although both methods are subjective and can result in false positive results, the DVC method is best suited to analysis of waters in which the number of different types of organisms present in the same sample is assumed to be small, such as processed waters. The advantages and disadvantages of each method are discussed

The Life Cycle of the Mayfly \u3ci\u3eStenacron Interpunctatum\u3c/i\u3e (Ephemeroptera: Heptageniidae)

Larval growth and development of Stenacron interpunctatum was studied for a one year period at Wildcat Creek, Indiana. Analysis of developmental stages and sue classes revealed three broods at different degrees of maturation at any one time of year. Broods emerged in early spring, mid-summer, and late summer-early fall, respectively; the former two overwintering in different stages of larval development, and the latter completing development in one growing season in warm temperatures and maturing at relatively smaller sizes. The population possessed a complex life cycle ranging from one generation per year to three generations every two years. General sampling over three growing seasons and controlled laboratory rearing support the conclusions

Microbial biofilm studies of the environmental control and life support system water recovery test for Space Station Freedom

NASA is developing a water recovery system (WRS) for Space Station Freedom to reclaim human waste water for reuse by astronauts as hygiene or potable water. A water recovery test (WRT) currently in progress investigates the performance of a prototype of the WRS. Analysis of biofilm accumulation, the potential for microbially influenced corrosion (MIC) in the WRT, and studies of iodine disinfection of biofilm are reported. Analysis of WRT components indicated the presence of organic deposits and biofilms in selected tubing. Water samples for the WRT contained acid-producing and sulfate-reducing organisms implicated in corrosion processes. Corrosion of an aluminum alloy was accelerated in the presence of these water samples; however, stainless steel corrosion rates were not accelerated. Biofilm iodine sensitivity tests using an experimental laboratory scale recycled water system containing a microbial check valve (MCV) demonstrated that an iodine concentration of 1 to 2 mg/L was ineffective in eliminating microbial biofilm. For complete disinfection, an initial concentration of 16 mg/L was required, which was gradually reduced by the MCV over 4 to 8 hours to 1 to 2 mg/L. This treatment may be useful in controlling biofilm formation

Analysis of debris from Spacelab Space Life Sciences-1

Airborne microbiological and particulate contamination generated aboard Spacelab modules is a potential safety hazard. In order to shed light on the characteristics of these contaminants, microbial and chemical/particulate analyses were performed on debris vacuumed from cabin and avionics air filters in the Space Life Sciences-1 (SLS-1) module of the Space Transportation System 40 (STS-40) mission 1 month after landing. The debris was sorted into categories (e.g., metal, nonmetal, hair/fur, synthetic fibers, food particles, insect fragments, etc.). Elemental analysis of particles was done by energy dispersive analysis of x rays (metals) and Fourier transform infrared spectroscopy (nonmetals). Scanning electron micrographs were done of most particles. Microbiological samples were grown on R2A culture medium and identified. Clothing fibers dominated the debris by volume. Other particles, all attributed to the crew, resulted from abrasions and impacts during missions operations (e.g., paint chips, plastic, electronic scraps and clothing fibers). All bacterial species identified are commonly found in the atmosphere or on the human body. Bacillus sp. was the most frequently seen bacterium. One of the bacterial species, Enterobacter agglomerans, could cause illness in crew members with depressed immune systems

Interim prediction method for low frequency core engine noise

A literature survey on low-frequency core engine noise is presented. Possible sources of low frequency internally generated noise in core engines are discussed with emphasis on combustion and component scrubbing noise. An interim method is recommended for predicting low frequency core engine noise that is dominant when jet velocities are low. Suggestions are made for future research on low frequency core engine noise that will aid in improving the prediction method and help define possible additional internal noise sources

Pens Up! The Development of the Ole Miss Ballpoint Pen

This thesis will document and analyze the ideation, research and design, production, and optimization processes for the Center for Manufacturing Excellence Senior Capstone design project. The Pens Up! team consisted of six team members- four mechanical engineering majors, one accounting major, and one business major- working together to continuously improve the Ole Miss ballpoint pen’s quality, design, and to standardize and eliminate wastes to its production process. After months of preparing and testing various ideas and ironing out kinks and mistakes, Pens Up! was able to produce a quality aluminum pen. This thesis will describe the various obstacles faced as well as the iterations taken in the optimization process of the Ole Miss Aluminum pen

Effects of deep-bedded finishing system on market pig performance, composition and pork quality

The purpose of this study was to compare effects of finishing environment on growth performance, pork quality and lipid composition of pork. Environments compared were standard confinement (CON) and deep-bedded semi-outdoor systems. The deep-bedded method employed in the current study was the use of hoop structures. Hoops are large, tent-like shelters with cornstalks or straw for bedding. Gilts ranging in weight from 59 to 71 kg were randomly assigned to treatments of Hoop (n = 50) and CON (n = 18) environments. Gilts were fed a two-phase dietary sequence, ad libitum for 45 days. Six gilts per treatment were selected for carcass composition and quality evaluation. The experiment was replicated a total of five times. Pigs raised in the Hoop environment gained significantly less and required significantly more feed for growth than pigs raised in the CON environment. Carcasses from CON-finished pigs were significantly fatter at the 10th rib, which lowered carcass percentage fat-free lean(FFL) and they also had greater loin marbling scores compared with carcasses from Hoop-finished pigs (P \u3c 0.05). Significant replication effects were noted on beginning weight, live weight, carcass weight, percentage FFL, backfat, lipid content and adipose firmness. Carcasses from Hoop pigs had lower proportions of palmitic acid (P \u3c 0.05), and higher proportions of oleic and linoleic acid (P \u3c 0.05) in the inner layer of adipose tissue. The proportion of saturated fatty acid was lower, and that of mono- and poly-unsaturated fatty acid was higher in the inner layer of the adipose tissue of Hoop pigs. Variations in fatty acid composition and lipid deposition may have been caused by environmental temperature, since decreases in environmental temperature accompanied compositional variation of the adipose, leading to higher proportions of monounsaturated fatty acid and lower proportions of saturated and polyunsaturated fatty acid in adipose tissue, regardless of treatment. Volatile profile analysis revealed that adipose tissue of Hoop pigs had significantly higher amounts of 3-butanal and heptanal compared with CON pigs, which may be related to the amount of oleic and linoleic acids composing the adipose tissue. These data indicate finishing pigs in hoop structures allows for exposure to fluctuating temperatures, which may influence the growth of pigs, as well as fatty acid composition and firmness of pork products

Lieb-Thirring Bound for Schr\"odinger Operators with Bernstein Functions of the Laplacian

A Lieb-Thirring bound for Schr\"odinger operators with Bernstein functions of the Laplacian is shown by functional integration techniques. Several specific cases are discussed in detail.Comment: We revised the first versio

Lunar Soil Erosion Physics for Landing Rockets on the Moon

To develop a lunar outpost, we must understand the blowing of soil during launch and landing of the new Altair Lander. For example, the Apollo 12 Lunar Module landed approximately 165 meters from the deactivated Surveyor Ill spacecraft, scouring its surfaces and creating numerous tiny pits. Based on simulations and video analysis from the Apollo missions, blowing lunar soil particles have velocities up to 2000 m/s at low ejection angles relative to the horizon, reach an apogee higher than the orbiting Command and Service Module, and travel nearly the circumference of the Moon [1-3]. The low ejection angle and high velocity are concerns for the lunar outpost