Environmental qualification testing of the prototype pool boiling experiment

The prototype Pool Boiling Experiment (PBE) flew on the STS-47 mission in September 1992. This report describes the purpose of the experiment and the environmental qualification testing program that was used to prove the integrity of the prototype hardware. Component and box level vibration and thermal cycling tests were performed to give an early level of confidence in the hardware designs. At the system level, vibration, thermal extreme soaks, and thermal vacuum cycling tests were performed to qualify the complete design for the expected shuttle environment. The system level vibration testing included three axis sine sweeps and random inputs. The system level hot and cold soak tests demonstrated the hardware's capability to operate over a wide range of temperatures and gave the project team a wider latitude in determining which shuttle thermal altitudes were compatible with the experiment. The system level thermal vacuum cycling tests demonstrated the hardware's capability to operate in a convection free environment. A unique environmental chamber was designed and fabricated by the PBE team and allowed most of the environmental testing to be performed within the project's laboratory. The completion of the test program gave the project team high confidence in the hardware's ability to function as designed during flight

Modeling real gases and liquids using a modified van der Waals equation of state.

Equations of state attempt to describe the relationship between temperature (T), pressure (P), and molar volume (v) for a given substance or mixture of substances. The ideal gas law is the simplest form of an equation of state. An ideal gas can be considered as a large quantity of small molecules that have no friction, no attractive or repulsive forces. The ideal gas law is a reasonable approximation at low pressures and high temperatures, but not at higher pressures and lower temperatures. Thus, better methods for predicting real gas behavior have been continuously introduced over the past 200 years. Another approximation is to assume that gas atomes and molecules behave as hard spheres. These spheres are incompressible and only repulsive forces are significant at the moment of collision. A recent modification made to the van der Waals equation of state (VDW) incorporates the hard sphere model, giving better representation of the van der Waals parameters over a broader temperature and pressure range. The efficacy of this modified van der Waals equation of state was assessed for six previously researched compounds -ethane, propane, n-butane, n-pentane, argon and water. Physical property charts (specifically molar volume and molar enthalpy charts) were developed for these substances using the original VDW and modified VDW, as well as the Redlich-Kwong (RK) and Redlich-Kwong-Soave (RKS) equations of state. Results for molar volume revealed that for the four hydrocarbons, the modified VDW compared best with the given experimental data, but not for argon and water. Results for molar enthalpy showed the original VDW compared more favorably with experimental data that the original VDW, but not as well as the RK equation of state

A Study for Semi-Passive Gravity Gradient Stabilization of Small Satellites

This paper gives the results of a dynamical analysis of the Globesat gravity gradient stabilized satellite in a 500 km circular orbit. The linearized equations of motion are developed and the stability of the satellite is investigated. The satellite is equipped with magnetic torquers for the purpose of providing attitude correction torques. These correction torques can be used to effect large changes in orientation and for producing small impulses for damping residual librational motions. The analysis shows that such a satellite can be captured into a gravity gradient stabilized mode, and that residual motions can be damped to small steady state values

Towards a Human-Centred Participatory Approach to Child Social Care Recordkeeping

In 2019 there were over 75,000 children and young people in out-of-home care in England and Wales. Recent estimates suggest that up to half a million British people were in state or voluntary care as children, around 1% of the adult population. While individual experiences vary enormously by time and place, care-experienced people share in common the intensive documentation of their lives by social workers, educators, health professionals and associated practitioners. A complex, fragmented legislative and regulatory framework governs the creation and use of these records at the national level. Under UK law a ‘care file’ must be retained for at least seventy-five years, so that a substantial legacy of care data is held across the public, voluntary and private sectors. MIRRA: Memory – Identity – Rights in Records – Access, a participatory research project co-produced with care leavers, investigated recordkeeping practices in child social care from multiple perspectives. Interviews, focus groups and workshops with stakeholders identified critical failings in the creation, use, management and access of care records, which do not account for the needs and capabilities of multiple stakeholders. These failings have direct impact on the wellbeing and health of care-experienced people throughout their lives. MIRRA researchers developed a human-centred participatory recordkeeping approach to child social care, which this article describes. The approach combines the participatory continuum model (Rolan, 2017) and the capabilities approach to social work, rooting child social care recordkeeping in information rights principles

Catalysts and inhibitors for MEA oxidation

AbstractAqueous monoethanolamine (MEA) was subjected to oxidation by O2/CO2 at 55 ∘C. Hydroxyethyl-formamide (HEF) and hydroxyethylimidazole (HEI) are the major oxidation products of MEA. Dissolved metals catalyze oxidation in the order copper > chromium/nickel > iron > vanadium. Inhibitors A, B and ethylenediaminetetracetic acid (EDTA) are effective degradation inhibitors. The addition of the expected inhibitors formaldehyde, formate or sodium sulfite had unintended effects on MEA losses. Total carbon and nitrogen analysis shows a greater than 90% closure of the material balance