Launch vehicle performance using metallized propellants

Metallized propellant propulsion systems are considered as replacements for the solid rocket boosters and liquid sustainer stages on the current launch vehicles: both the Space Transportation System (STS) and the Titan 4. Liquid rocket boosters for the STS were analyzed as replacements for current solid rocket boosters. These boosters can provide a liquid propulsion system within the volume constraints of a solid rocket booster. A replacement for the Space Shuttle Main Engines using metallized O2/H2/Al was studied. The liquid stages of the Titan 4 were also investigated; the Aerozine-50 (A-50) fuel was replaced with metallized storable A-50/Al. A metallized propellant is similar to a traditional liquid propellant. However, it has metal particles, such as aluminum, that are suspended in a gelled fuel, such as hydrogen, RP-1, A-50 or monomethyl hydrazine (MMH). The fuels then undergo combustion with liquid oxygen or nitrogen tetroxide (NTO). These propellants provide options for increasing the performance of existing launch vehicle chemical propulsion systems by increasing fuel density or specific impulse or both. These increases in density and specific impulse can significantly reduce the propulsion system liftoff weight and allow a liquid rocket booster to fit into the same volume as an existing solid rocket booster. Also, because gelled fuels are akin to liquid propellants, metallized systems can provide enhanced controllability over solid propulsion systems. Gelling of the propellant also reduces the sensitivity to impacts and consequently reduces the propellant explosion hazard

A CRITIQUE OF THE CONSTANT ELASTICITY OF TRANSFORMATION (CET) LINEAR SUPPLY SYSTEM

An elusive restriction maintained in earlier CET supply models with three or more products is shown to result in a potentially serious misspecification. Its impact on empirical estimates is found to be substantial, and an alternative formulation is presented which overcomes the problem while still maintaining the CET hypothesis.Research Methods/ Statistical Methods,

Flesh on the Bones: Animal Bodies in Atlantic Roundhouses

This volume presents the state of research across Europe to illustrate how comparable interpretative frameworks are used by archaeologists working with both prehistoric and historical societies

PEPFAR Public Health Evaluation-Care and Support -Phase I Kenya

Phase 1, a survey of 120 care facilities in Kenya and Uganda, found that over 90% of facilities provided some level of clinical, psychological,and preventive care. Pain control was very limited with paracetamol often the only analgesic. In focus group discussions, patients appreciated free care and positive attitudes from staff, but said that services would be improved by more staff, shorter queues, and reliable drug supplies

Changes in FGM/C in Somaliland: Medical narrative driving shift in types of cutting

In Somalia, female genital mutilation/cutting (FGM/C) prevalence is nearly universal at 98 percent. This qualitative study sought to explore: 1) views and experiences of married and unmarried men and women on FGM/C and potential changes in its practice; 2) individual, family, and societal factors contributing to any changes, or continuation of FGM/C; 3) the knowledge, views, and experiences of healthcare workers who offer FGM/C services and their role as change agents rather than providers; and 4) how healthcare systems’ capacities can be strengthened for management and prevention. The study finds that normative changes appear to be occurring in Somaliland society and there is a growing readiness for change. However, the nature of that change is not toward the abandonment of the practice per se, but rather its transformation into a more socially acceptable version, thus reinforcing the continuity of the practice

PEPFAR Public Health Evaluation -Care and Support -Phase I Uganda

Phase 1, a survey of 120 care facilities in Kenya and Uganda, found that over 90% of facilities provided some level of clinical, psychological,and preventive care. Pain control was very limited with paracetamol often the only analgesic. In focus group discussions, patients appreciated free care and positive attitudes from staff, but said that services would be improved by more staff, shorter queues, and reliable drug supplies

Ethical Problems in Class Arbitration

This article examines two significant conflicts of interest that arise in class arbitration in six parts. Part II provides background on the recent evolution of class arbitration, explaining how the Supreme Court had decided several cases involving class arbitration but has not explicitly ruled that class actions are either permitted or forbidden. Part III discusses the conflicts of interest that could arise at the beginning of class arbitration. Part IV discusses conflicts of interest that arise at the end of class arbitration. Part V of this article argues that if and when Congress amends the Federal Arbitration Act to statutorily permit class arbitration in light of Concepcion, a fully developed statute should be enacted to permit limited judicial supervision of the process of selecting class arbitrators and the process of issuing a class award or approving a class settlement. Part VI concludes

PEPFAR Public Health Evaluation - Care and Support - Phase 2 Uganda

Phase 2 consisted of a longitudinal cohort study to measure patient-reported outcomes of care and support, a costing survey, and qualitative interviews to understand patient and carer experiences

PEPFAR Public Health Evaluation - Care and Support - Phase 2 Kenya

Phase 2 consisted of a longitudinal cohort study to measure patient-reported outcomes of care and support, a costing survey, and qualitative interviews to understand patient and carer experiences