A model for silicon solar cell performance in space Final report

Model for silicon solar cell performance in spac

Contamination control by use of ethylene oxide

The uses of ethylene oxide as a decontaminating agent for planetary quarantine related applications are reported. Aspects discussed include: applications and limitations, chemical and physical properties, germicidal activity, methods of applications, and effects on personnel

Proton-induced damage to silicon solar cell assemblies a state-of-the-art survey Quarterly report

Literature review on proton damage of irradiated silicon solar cell

Effects of uniform damage to silicon solar cells

Uniform damage to silicon solar cells by fast protons or electron

Vortex Fractionalization in a Josephson Ladder

We show numerically that, in a Josephson ladder with periodic boundary conditions and subject to a suitable transverse magnetic field, a vortex excitation can spontaneously break up into two or more fractional excitations. If the ladder has N plaquettes, and N is divisible by an integer q, then in an applied transverse field of 1/q flux quanta per plaquette the ground state is a regular pattern of one fluxon every q plaquettes. When one additional fluxon is added to the ladder, it breaks up into q fractional fluxons, each carrying 1/q units of vorticity. The fractional fluxons are basically walls between different domains of the ground state of the underlying 1/q lattice. The fractional fluxons are all depinned at the same applied current and move as a unit. For certain applied fields and ladder lengths, we show that there are isolated fractional fluxons. It is shown that the fractional fluxons would produce a time-averaged voltage related in a characteristic way to the ac voltage frequency.Comment: 13 Figures. 10 page

Should I Stay or Should I Go?: Factors Impacting the Decision to Study Abroad Among Students Who Have Expressed Intent

Study abroad is recognized as a valuable and increasingly essential aspect of higher education in America. Yet, for all the positive attention and high-profile initiatives aimed at expanding participation, the percentage of U.S. undergraduate who studies abroad remains small. Developing a better understanding of the factors that contribute to or hinder study abroad participation is critical to expanding participation. The purpose of this dissertation is to examine factors that influence participation among students at the University of Massachusetts Amherst who have expressed formal intent to study abroad. Specifically, this dissertation investigates who is more likely to study abroad and who is less likely and why students who intend to study abroad do not. To answer these questions, this study employs both quantitative and qualitative research methods through convergent parallel design. Together, the results of the binary logistic regression analysis and focus group interviews provide an abundance of information on the variety of factors that influence participation among students who intend to study abroad. Positive influential predictors include GPA, honors college membership, prior travel abroad 3 or more times and having studied a foreign language at the college level. Negative predictors are identifying an interest in study abroad from University outreach, being a transfer student, citing money as the biggest obstacle to study abroad, citing “other” as the biggest obstacle to study abroad, citing not being able to graduate on times as the biggest obstacle to study abroad and indicating at the time of completion of the study abroad profile that there is only some chance that they will study abroad. Focus group findings reveal that cost, academic barriers, and not wanting to miss out on time at the University deterred students who had expressed interest in study abroad from actually doing so

Deflections of beam columns on multiple supports

Lateral deflections of beam columns on multiple equally spaced supports are calculated using the STAGS nonlinear structural analysis computer program. Three lateral loadings are considered, uniform, linear, and uniform over only the center bay. Two types of boundary conditions are considered at the end supports, clamped, and simple support. The effect of an initial sinusoidal imperfection are considered. Deflections in the center and end bays of the beam columns are presented as a function of applied axial compressive load. As the number of bays becomes large, the effect of boundary conditions on the deflections in the center bays diminishes. For cases involving a uniform or linearly varying load, imperfections can have a much larger effect on deflections in the center bays than can lateral pressure

Current research on shear buckling and thermal loads with PASCO: Panel Analysis and Sizing Code

The PASCO computer program to obtain the detailed dimensions of optimum stiffened composite structural panels is described. Design requirements in terms of inequality constraints can be placed on buckling loads or vibration frequencies, lamina stresses and strains, and overall panel stiffness for each of many load conditions. General panel cross sections can be treated. An analysis procedure involving a smeared orthotropic solution was investigated. The conservatism in the VIPASA solution and the danger in a smeared orthotropic solution is explored. PASCO's capability to design for thermal loadings is also described. It is emphasized that design studies illustrate the importance of the multiple load condition capability when thermal loads are present