Curvature Constraints from the Causal Entropic Principle

Current cosmological observations indicate a preference for a cosmological constant that is drastically smaller than what can be explained by conventional particle physics. The Causal Entropic Principle (Bousso, {\it et al}.) provides an alternative approach to anthropic attempts to predict our observed value of the cosmological constant by calculating the entropy created within a causal diamond. We have extended this work to use the Causal Entropic Principle to predict the preferred curvature within the "multiverse". We have found that values larger than $\rho_k = 40\rho_m$ are disfavored by more than 99.99% and a peak value at $\rho_{\Lambda} = 7.9 \times 10^{-123}$ and $\rho_k =4.3 \rho_m$ for open universes. For universes that allow only positive curvature or both positive and negative curvature, we find a correlation between curvature and dark energy that leads to an extended region of preferred values. Our universe is found to be disfavored to an extent depending the priors on curvature. We also provide a comparison to previous anthropic constraints on open universes and discuss future directions for this work.Comment: 5 pages, 3 Figure

AEDPA Repeal

The Antiterrorism and Effective Death Penalty Act of 1996 (“AEDPA”) dramatically altered the scope of federal habeas corpus. Enacted in response to a domestic terrorism attack, followed by a capital prosecution, and after decades of proposals seeking to limit post conviction review of death sentences, and Supreme Court rulings severely limiting federal habeas remedies, AEDPA was ratified with little discussion or deliberation. The law and politics of death penalty litigation, which had been particularly active since the U.S. Supreme Court invalidated all death penalty schemes in its 1972 ruling in Furman v. Georgia, culminated in restrictions for all federal habeas corpus cases, whether capital or non capital. Still more perverse, the impact of AEDPA was particularly strong in non capital cases. Since its enactment, AEDPA has been widely criticized by academics, legislators, and judges, for erecting a complex, poorly drafted set of procedural barriers, and for limiting federal review on the merits of most constitutional claims. This Article examines statutory approaches designed to restore federal habeas corpus. Any partial or complete repeal of AEDPA raises complex and unexplored issues. The central challenge is that AEDPA operates alongside decades of Supreme Court created restrictions of federal habeas corpus. In this Article, we walk through proposals for how AEDPA provisions could be amended, benefits and costs of each change, and how Supreme Court doctrine affects each choice. AEDPA repeal is not as simple as eliminating the judicially created doctrine of qualified immunity in civil rights litigation. However, real improvements to federal habeas practice are achievable, and in this Article, we provide a legislative roadmap for habeas reform through AEDPA repeal

Simulated Space Environmental Effects on Thin Film Solar Array Components

The Lightweight Integrated Solar Array and Transceiver (LISA-T) experiment consists of thin-film, low mass, low volume solar panels. Given the variety of thin solar cells and cover materials and the lack of environmental protection afforded by typical thick coverglasses, a series of tests were conducted in Marshall Space Flight Center's Space Environmental Effects Facility to evaluate the performance of these materials. Candidate thin polymeric films and nitinol wires used for deployment were also exposed. Simulated space environment exposures were selected based on SSP 30425 rev. B, "Space Station Program Natural Environment Definition for Design" or AIAA Standard S-111A-2014, "Qualification and Quality Requirements for Space Solar Cells." One set of candidate materials were exposed to 5 eV atomic oxygen and concurrent vacuum ultraviolet (VUV) radiation for low Earth orbit simulation. A second set of materials were exposed to 1 MeV electrons. A third set of samples were exposed to 50, 500, and 750 keV energy protons, and a fourth set were exposed to >2,000 hours of ultraviolet radiation. A final set was rapidly thermal cycled between -50 and +120 C. This test series provides data on enhanced power generation, particularly for small satellites with reduced mass and volume resources. Performance versus mass and cost per Watt is discussed

Undergraduate Students’ Perception of Leadership Development Programs and Leadership Self-Efficacy

Colleges and universities across the United States face continual pressure to meet enrollment and retention goals, as budgets in this performance-based environment continue to become more important. On-campus student involvement, such as in undergraduate leadership development programs, has been shown to have a positive influence on both student retention and success. A survey was utilized to examine leadership self-efficacy and engagement of undergraduate students that participated in campus-based leadership development programs and explore some motivators (contributing factors) and barriers (detracting factors) to involvement in those programs. One emergent theme within contributing factors to participation was alignment with personal goals (74.7%), whereas, a theme for detracting factors was lack of time to invest in the leadership opportunity (51.1%). Exploration of which factors contributed to and detracted from leadership development participation showed that contributing factors were a positive and significant predictor of leadership self-efficacy. For every one unit increase in contributing factors, leadership self-efficacy score increased by β - = .38 standard deviations. This study encourages leadership educators to examine their own leadership development programs and build recruitment strategies to increase engagement among student demographics such as male students, non-White students, and first-generation college students. In the future, researchers could consider including students that did not participate in leadership programs to gain more valuable insights on the motivators and the barriers that students face to participation in these programs

Effects of Oxygen Partial Pressure on the Surface Tension of Liquid Aerospace Alloys

No abstract availabl

Space Environment Testing of Photovoltaic Array Systems at NASA's Marshall Space Flight Center

To successfully operate a photovoltaic (PV) array system in space requires planning and testing to account for the effects of the space environment. It is critical to understand space environment interactions not only on the PV components, but also the array substrate materials, wiring harnesses, connectors, and protection circuitry (e.g. blocking diodes). Key elements of the space environment which must be accounted for in a PV system design include: Solar Photon Radiation, Charged Particle Radiation, Plasma, and Thermal Cycling. While solar photon radiation is central to generating power in PV systems, the complete spectrum includes short wavelength ultraviolet components, which photo-ionize materials, as well as long wavelength infrared which heat materials. High energy electron radiation has been demonstrated to significantly reduce the output power of III-V type PV cells; and proton radiation damages material surfaces - often impacting coverglasses and antireflective coatings. Plasma environments influence electrostatic charging of PV array materials, and must be understood to ensure that long duration arcs do not form and potentially destroy PV cells. Thermal cycling impacts all components on a PV array by inducing stresses due to thermal expansion and contraction. Given such demanding environments, and the complexity of structures and materials that form a PV array system, mission success can only be ensured through realistic testing in the laboratory. NASA's Marshall Space Flight Center has developed a broad space environment test capability to allow PV array designers and manufacturers to verify their system's integrity and avoid costly on-orbit failures. The Marshall Space Flight Center test capabilities are available to government, commercial, and university customers. Test solutions are tailored to meet the customer's needs, and can include performance assessments, such as flash testing in the case of PV cells