Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Geology, 1948. / MIT Science Library copy: lacking maps; in binder, 31 cm. / Accompanied by: Geologic maps of the Boston metropolitan area. [40] p. : col. maps ; 54 cm. Vita. / Includes bibliographical references. / by Kenneth Grenville Bell. / Ph.D.

Bacterial pathogens on the surfaces of raw produce may be difficult to remove for identification and enumeration. The first part of this project examined whether ultrasonic treatment (40 kHz) of a rinse solution would enhance recovery of Salmonella spp. from various produce surfaces. Strawberries, apples, and cantaloupe were surface inoculated with a five-strain cocktail of nalidixic acid resistant Salmonella spp. Samples were subjected to one of six different treatments using different combinations of agitation methods (manual shaking or ultrasound), diluent temperatures (25°C and 40°C), and agitation times (60 and 120 seconds). After treatment, diluent was spiral plated onto tryptic soy agar supplemented with 50 ppm of nalidixic acid and plates were incubated at 37°C for 48 hours. Results from this study indicate that ultrasonic treatment of a rinse solution did not enhance or diminish recovery of Salmonella spp. from produce surfaces, as compared to manual agitation. The effects of diluent temperature and exposure time appeared to have a significant effect on recovery, depending on the type of produce. The second part of this project used a computer imaging system to determine the surface area of various types of produce. The imaging system acquired and stored multiple images of the produce samples. From these images, surface fitting and approximation of a 3-D wire frame model were used to calculate surface area. From these measurements, it was determined that there were statistical relationships between surface area and weight. Surface area measurements were used to develop equations to predict surface area from weight measurements. / Master of Science

Revenue insurance with shallow loss protection for farmers has been introduced recently. A common attribute of most shallow loss proposals is that they would be arearevenue triggered. The impact on optimal hedge ratios of combining these shallow loss insurance proposals with deep loss farm-level insurance is examined. Since crop insurance, commodity programs and forward pricing are commonly used concurrently to manage crop revenue risk, the optimal combinations of these tools are explored. Numerical analysis in the presence of yield, basis and futures price variability is used to find the futures hedge ratio which maximizes the certainty equivalent of a risk averse producer. The results generally reveal a lower optimal hedge ratio with area-insurance than with individual insurance and show that shallow loss revenue insurance tends to slightly increase optimal hedge ratios.

The United States Department of Defense tests its weapons systems to many different real as well as man-made environments prior to deploying the systems to the troops. The intent of testing is to insure the systems function as they are intended without adverse reactions. One of the required tests is a Radiation Hazards test to insure that non-ionizing radio frequency waves generated by transmitters, such as radios and jammers, do not cause harm to personnel, ordnance or fuel. This test is typically performed at a DoD test lab and data taken at the lab is used to determine safe operating parameters for a particular piece of equipment. This thesis presents measurements as well as mathematical models to demonstrate methods that can be employed to take more relevant Radiation Hazards data.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.