Characterization of the space shuttle reaction control system engine

A computer program was developed and written in FORTRAN 5 which predicts the transient and steady state performance and heat transfer characteristics of a pulsing GO2/GH2 rocket engine. This program predicts the dynamic flow and ignition characteristics which, when combined in a quasi-steady state manner with the combustion and mixing analysis program, will provide the thrust and specific impulse of the engine as a function of time. The program also predicts the transient and steady state heat transfer characteristics of the engine using various cooling concepts. The computer program, test case, and documentation are presented. The program is applicable to any system capable of utilizing the FORTRAN 4 or FORTRAN 5 language

Developing a conceptual framework for assessing the socio-economic benefits of regeneration projects in the UK

Recent decades have witnessed the evolution of building assessment methods for appraising the sustainability performance of building projects. In the UK for instance, the Government has initiated a number of assessment/evaluation methods to deal with some of the environmental problems associated with regeneration programmes. But attempts aimed at implementing sustainability assessment primarily have been limited to the environmental impact of buildings, with the socio-economic aspects often neglected. The findings of an exploratory case study on a housing regeneration project, which adopted a combination of literature review and focus-group interview approach with eight key stakeholders for data collection in the UK, are presented in this paper. The emergent framework developed and presented in hierarchical order in this paper incorporates project level and wider community socio-economic sustainability indicators

Calorimetric Measurements of Magnetic-Field-Induced Inhomogeneous Superconductivity Above The Paramagnetic Limit

We report the first magneto-caloric and calorimetric observations of a magnetic-field-induced phase transition within a superconducting state to the long-sought exotic "FFLO" superconducting state first predicted over 50 years ago. Through the combination of bulk thermodynamic calorimetric and magnetocaloric measurements in the organic superconductor $\kappa$ - (BEDT-TTF)$_2$Cu(NCS)$_2$, as a function of temperature, magnetic field strength, and magnetic field orientation, we establish for the first time that this field-induced first-order phase transition at the paramagnetic limit $H_p$ for traditional superconductivity is to a higher entropy superconducting phase uniquely characteristic of the FFLO state. We also establish that this high-field superconducting state displays the bulk paramagnetic ordering of spin domains required of the FFLO state. These results rule out the alternate possibility of spin-density wave (SDW) ordering in the high field superconducting phase. The phase diagram determined from our measurements --- including the observation of a phase transition into the FFLO phase at $H_p$ --- is in good agreement with recent NMR results and our own earlier tunnel-diode magnetic penetration depth experiments, but is in disagreement with the only previous calorimetric report.Comment: 5 pages, 5 figure

Maximum Edge-Disjoint Paths in kk-sums of Graphs

We consider the approximability of the maximum edge-disjoint paths problem (MEDP) in undirected graphs, and in particular, the integrality gap of the natural multicommodity flow based relaxation for it. The integrality gap is known to be $\Omega(\sqrt{n})$ even for planar graphs due to a simple topological obstruction and a major focus, following earlier work, has been understanding the gap if some constant congestion is allowed. In this context, it is natural to ask for which classes of graphs does a constant-factor constant-congestion property hold. It is easy to deduce that for given constant bounds on the approximation and congestion, the class of "nice" graphs is nor-closed. Is the converse true? Does every proper minor-closed family of graphs exhibit a constant factor, constant congestion bound relative to the LP relaxation? We conjecture that the answer is yes. One stumbling block has been that such bounds were not known for bounded treewidth graphs (or even treewidth 3). In this paper we give a polytime algorithm which takes a fractional routing solution in a graph of bounded treewidth and is able to integrally route a constant fraction of the LP solution's value. Note that we do not incur any edge congestion. Previously this was not known even for series parallel graphs which have treewidth 2. The algorithm is based on a more general argument that applies to $k$-sums of graphs in some graph family, as long as the graph family has a constant factor, constant congestion bound. We then use this to show that such bounds hold for the class of $k$-sums of bounded genus graphs

Predicting Women's Recidivism Using the Dynamic Risk Assessment for Offender Re-Entry: Preliminary Evidence of Predictive Validity With Community-Sentenced Women Using a "Gender-Neutral" Risk Measure

Although men and women share risk factors for offending, some scholars suggest these factors operate differently across gender and that women-specific risk factors are neglected in existing “gender-neutral” risk assessment tools. This article explored the predictive validity of one gender-neutral risk assessment tool—the Dynamic Risk Assessment for Offender Re-Entry (DRAOR)—with matched samples of women and men serving community supervision sentences. Total DRAOR scores had comparative predictive validity across gender. For women and men, the DRAOR predicted reconviction over a static risk measure. The findings support the general premise of gender neutrality, but do not necessarily suggest the DRAOR, or gender-neutral tools more broadly, are the best tools for use with women

The Complexity of Graph-Based Reductions for Reachability in Markov Decision Processes

We study the never-worse relation (NWR) for Markov decision processes with an infinite-horizon reachability objective. A state q is never worse than a state p if the maximal probability of reaching the target set of states from p is at most the same value from q, regard- less of the probabilities labelling the transitions. Extremal-probability states, end components, and essential states are all special cases of the equivalence relation induced by the NWR. Using the NWR, states in the same equivalence class can be collapsed. Then, actions leading to sub- optimal states can be removed. We show the natural decision problem associated to computing the NWR is coNP-complete. Finally, we ex- tend a previously known incomplete polynomial-time iterative algorithm to under-approximate the NWR

Design topology of a remote-controlled bi-directional rotation of an A.C. fan with speed control

The use of remote control for alternating current fans in homes/offices is one of the applications of electronics that enhances human comfort. It should therefore not be seen as luxury, rather, it should be taken as a basic requirement of life. In this study, the bi-directional rotation and speed control of ac fan were achieved using ardiuno microcontroller and tuned capacitors circuit. The use of the new state-of- the art technique in this work is significant because it helped in over-coming the drawbacks associated with the use of inductive, resistive and phase angle controlled regulators. The significance of this study will be of great benefit to physically challenged and aged persons who need to have their comforts in their various places of sitting. The designed topology of the work was executed and achieved. Reliability test carried out on the finished work showed better efficiency

Double Charge Exchange And Configuration Mixing

The energy dependence of forward pion double charge exchange reactions on light nuclei is studied for both the Ground State transition and the Double-Isobaric-Analog-State transitions. A common characteristic of these double reactions is a resonance-like peak around 50 MeV pion lab energy. This peak arises naturally in a two-step process in the conventional pion-nucleon system with proper handling of nuclear structure and pion distortion. A comparison among the results of different nuclear structure models demonstrates the effects of configuration mixing. The angular distribution is used to fix the single particle wave function.Comment: Added 1 figure (now 8) corrected references and various other change