Design, development and demonstration of a warm gas distribution system Quarterly report, period ending 31 Mar. 1968

Component tests and system assembly for hydrazine fuel gas distribution system of torque generator for spacecraft attitude contro

Risk, responsibilities and rights: reassessing the ‘economic causes of crime’ thesis in a recession

This paper explores competing accounts of an apparent inversion of the previously-prevailing relationship between young people's unemployment and the incidence of youth offending at a time of economic recession. It begins by highlighting the faltering association between unemployment and offending, and considers the paradoxical implications for risk-based methodologies in youth justice practice. The paper then assesses explanations for the changing relationship that suggest that youth justice policies have successfully broken the unemployment-offending link; and alternatively that delayed effects of recession have yet to materialise, by reference to the work of four Inter-governmental organisations and to youth protests beyond the UK. In place of ever more intensive risk analyses, the paper then focusses on the adverse effects of unemployment on social cohesion, and proposes a rights-based approach to youth justice that recognises the growing disjuncture between the rights afforded to young people and the responsibilities expected of them

Measurements of the ϒ(1S), ϒ(2S), and ϒ(3S) differential cross sections in pp collisions at s=7TeV

Differential cross sections as a function of transverse momentum pTpT are presented for the production of ϒ(nS)ϒ(nS) (n = 1, 2, 3) states decaying into a pair of muons. Data corresponding to an integrated luminosity of 4.9View the MathML sourcefb−1 in pp collisions at View the MathML sources=7TeV were collected with the CMS detector at the LHC. The analysis selects events with dimuon rapidity |y|<1.2|y|<1.2 and dimuon transverse momentum in the range View the MathML source10<pT<100GeV. The measurements show a transition from an exponential to a power-law behavior at View the MathML sourcepT≈20GeV for the three ϒ states. Above that transition, the ϒ(3S)ϒ(3S) spectrum is significantly harder than that of the ϒ(1S)ϒ(1S). The ratios of the ϒ(3S)ϒ(3S) and ϒ(2S)ϒ(2S) differential cross sections to the ϒ(1S)ϒ(1S) cross section show a rise as pTpT increases at low pTpT, then become flatter at higher pTpT

Optimal design of hybrid rocket motors for microgravity platform

A nested direct/indirect method is used tofind the optimal design for a microgravity platform which is based on a hybrid sounding rocket. The direct optimization of the parameters that affect the motor design is coupled with the indirect trajectory optimization to maximize a given mission performance index. A gas-pressure feed system is used, with three different propellant combinations. The feed system exploits a pressurizing gas, namely, helium, when hydrogen peroxide or liquid oxygen is used as an oxidizer. The simplest blowdown design is compared with a more complex pressurizing system, which has an additional gas tank that allows for a phase with constant propellant tank pressure. Only self-pressurization is considered with nitrous oxide; two different models are used to describe the behavior of the tank pressurization. The simplest model assumes liquid/vapor equilibrium. A two-phase model is also proposed: Saturated vapor and superheated liquid are considered and the liquid/vapor mass transfer evaluation is based on the liquid spinodal line. Results show that the different tank-pressurization models yield minimal differences of the optimal motor characteristics. Performance differs slightly due to the different mass of the residual oxidizer. The propellant comparison for the present case shows better performance for hydrogen peroxide/polyethylene with respect to liquid oxygen/hydroxyl-terminated polybutadiene, while nitrous oxide/hydroxyl-terminated polybutadiene remains attractive for system simplicity and low cost