Series-parallel method of direct solar array regulation

A 40 watt experimental solar array was directly regulated by shorting out appropriate combinations of series and parallel segments of a solar array. Regulation switches were employed to control the array at various set-point voltages between 25 and 40 volts. Regulation to within + or - 0.5 volt was obtained over a range of solar array temperatures and illumination levels as an active load was varied from open circuit to maximum available power. A fourfold reduction in regulation switch power dissipation was achieved with series-parallel regulation as compared to the usual series-only switching for direct solar array regulation

Electromagnetic propulsion test facility

A test facility for the exploration of electromagnetic propulsion concept is described. The facility is designed to accommodate electromagnetic rail accelerators of various lengths (1 to 10 meters) and to provide accelerating energies of up to 240 kiloJoules. This accelerating energy is supplied as a current pulse of hundreds of kiloAmps lasting as long as 1 millisecond. The design, installation, and operating characteristics of the pulsed energy system are discussed. The test chamber and its operation at pressures down to 1300 Pascals (10 mm of mercury) are described. Some aspects of safety (interlocking, personnel protection, and operating procedures) are included

Self-protecting solid state isolated switch

Solid state switch has following capabilities: (1) Hybrid or IC from compatible with direct mounting on solar array substrate; (2) Continuous signal is not required to hold it in either on or off state; (3) Separate signal lines for on and off control; (4) Electrically isolated from input signals; and (5) Current surges will not cause switch failure

Laboratory 15 kV high voltage solar array facility

The laboratory high voltage solar array facility is a photoelectric power generating system. Consisting of nine modules with over 23,000 solar cells, the facility is capable of delivering more than a kilowatt of power. The physical and electrical characteristics of the facility are described

The Effects of Heat-Killed Echinostomatid Parasites on Mice Treated with Dextran Sodium Sulfate (DSS)

Objective: Autoimmune diseases are chronic, incurable, and affect approximately 50 million Americans. This is a strong need for better ways to treat autoimmune diseases. Parasites and parasite proteins have been observed to protect mice from symptoms of induced colitis in mice treated with dextran sodium sulfate (DSS), a model for inflammatory bowel disease (IBD). I hypothesize that non-living echinostomatid parasites, given during DSS treatment, can decrease intestinal inflammation and weight loss, providing a possible novel treatment for IBD. Methods: A range of DSS concentrations (0.5%-3%) were delivered to female C57BL/6 mice in their drinking water in order to determine the concentration that induced colitis but not severe morbidity; 1% DSS was determined to be optimal. Next, two groups of mice were administered 1% DSS in their drinking water for the first six days of the nine-day experiment, while two groups received regular water throughout. The mice in one of the DSS treatment groups and one of the water control groups were orally administered heat-killed metacercariae in PBS on the third day of the experiment, while the remaining mice were administered just PBS as a control treatment. Weight of the mice and intestinal distress were monitored, as was water and food consumption. At the end of the experiment, colon lengths were measured and splenic cytokines (IL-4, IFN-γ, IL-10, and IL-2) were assessed by ELISA. Results: Mice with DSS induced colitis that received the parasite treatment demonstrated more weight loss (p=0.01) and poorer intestinal distress (p=0.02) on the ninth day when compared to mice with DSS induced colitis that did not receive parasite treatment. The spleens from mice receiving DSS and parasite treatment showed lower levels of regulatory cytokine IL-2 than mice receiving DSS but not parasite treatment (p=0.013). Additionally, mice treated with DSS consumed less food on average than untreated mice (p\u3c0.0001). Conclusion: In contrast to my hypothesis, I found that feeding mice heat-killed echinostomatid parasites during DSS treatment did not improve symptoms of colitis. Future studies could be performed to determine if non living parasites can counteract symptoms of colitis, a possible novel treatment for patients with IBD

Structural and thermal response of 30 cm diameter ion thruster optics

Tabular and graphical data are presented which are intended for use in calibrating and validating structural and thermal models of ion thruster optics. A 30 cm diameter, two electrode, mercury ion thruster was operated using two different electrode assembly designs. With no beam extraction, the transient and steady state temperature profiles and center electrode gaps were measured for three discharge powers. The data showed that the electrode mount design had little effect on the temperatures, but significantly impacted the motion of the electrode center. Equilibrium electrode gaps increased with one design and decreased with the other. Equilibrium displacements in excess of 0.5 mm and gap changes of 0.08 mm were measured at 450 W discharge power. Variations in equilibrium gaps were also found among assemblies of the same design. The presented data illustrate the necessity for high fidelity ion optics models and development of experimental techniques to allow their validation

Operational compatibility of 30-centimeter-diameter ion thruster with integrally regulated solar array power source

System tests were performed in which Integrally Regulated Solar Arrays (IRSA's) were used to directly power the beam and accelerator loads of a 30-cm-diameter, electron bombardment, mercury ion thruster. The remaining thruster loads were supplied from conventional power-processing circuits. This combination of IRSA's and conventional circuits formed a hybrid power processor. Thruster performance was evaluated at 3/4- and 1-A beam currents with both the IRSA-hybrid and conventional power processors and was found to be identical for both systems. Power processing is significantly more efficient with the hybrid system. System dynamics and IRSA response to thruster arcs are also examined