Optimal design of gas adsorption refrigerators for cryogenic cooling

The design of gas adsorption refrigerators used for cryogenic cooling in the temperature range of 4K to 120K was examined. The functional relationships among the power requirement for the refrigerator, the system mass, the cycle time and the operating conditions were derived. It was found that the precool temperature, the temperature dependent heat capacities and thermal conductivities, and pressure and temperature variations in the compressors have important impacts on the cooling performance. Optimal designs based on a minimum power criterion were performed for four different gas adsorption refrigerators and a multistage system. It is concluded that the estimates of the power required and the system mass are within manageable limits in various spacecraft environments

Feasibility study of using a two-plate model to approximate the TDRSS solar pressure effects

An investigation was performed to determine the feasibility of using a two plate model to approximate the Tracking and Data Relay Satellite (TDRS) in orbit propagation, taking into account the effects of solar radiation pressure. The two plate model comprises one plate which always points to the Earth, and the other which is hinged to an axis normal to the orbital plane and is always rotated so that its normal makes a minimum angle with the direction of the sun. The results indicate that it is sufficient to take three parameters, the areas of the two plates and the reflectivity of the Earth pointing plate, to achieve an accuracy of one meter during a 24 hour orbit propagation

Instability of three dimensional conformally dressed black hole

The three dimensional black hole solution of Einstein equations with negative cosmological constant coupled to a conformal scalar field is proved to be unstable against linear circularly symmetric perturbations.Comment: 5 pages, REVTe

Pre-Congestion Notification Encoding Comparison

DiffServ mechanisms have been developed to support Quality of Service (QoS). However, the level of assurance that can be provided with DiffServ without substantial over-provisioning is limited. Pre-Congestion Notification (PCN) investigates the use of per-flow admission control to provide the required service guarantees for the admitted traffic. While admission control will protect the QoS under\ud normal operating conditions, an additional flow termination mechanism is necessary in the times of heavy congestion (e.g. caused by route changes due to link or node failure).\ud Encoding and their transport are required to carry the congestion and pre-congestion information from the congestion and pre-congestion points to the decision points. This document provides a survey of\ud several encoding methods, using comparisons amongst them as a way to explain their strengths and weaknesses.\u

Workfare in the undemocratic states: the case of China

This article examines the problems caused by workfare in China. It is found that China’s public assistance scheme is managed mainly by volunteers and government officials who do not necessarily possess relevant qualifications. Also, welfare claimants’ benefits can be ceased without going through a rigorous procedure; they can hardly challenge the decisions of the authority because China’s judicial system is interfered by central and local senior officials. This article concludes that workfare is a product of Western democratic countries; its implementation in undemocratic states will only increase power abuses among welfare bureaucrats and threaten the rights of claimants. </jats:p

Construction of a cosmic ray air shower telescope

The telescope under construction is mainly for the purpose of locating the arrival directions of energetic particles and quanta which generate air showers of sizes 10 to the 5th power to 10 to the 6th power. Both fast timing method and visual track method are incorporated in determining the arrival directions. The telescope is composed of four stations using scintillators and neon flash tubes as detectors. The system directional resolution is better than 1.5 deg

The ER-2 meteorological measurement system

The objectives of ER-2 Meteorological Measurement System (MMS) are: (1) to measure the meteorological parameters (pressure, temperature, and the three dimensional wind vector) accurately; (2) to provide high resolution data on atmospheric state variables and aircraft flight track to ER-2 investigators on a timely basis; and (3) to conduct collaborative research in atmospheric dynamics and chemistry. A summary of progress and results are presented

Measurement of shower electrons and muons using a small air shower array

A small air shower array has been used to measure the size spectrum of air showers at sea level in the size range 6.10 to the 3rd power to 10 to the 6th power. The result fitted with the power law gives an index 2.79 + or - 0.11 for the differential spectrum. Lateral distribution of electrons fitted with the well known NKG function results in an age parameter s = 1.35 for core distances less than 30m and s = 0.8 for longer core distances. Lateral distribution of muons follows the general shape of Greisen's relation but is much higher in intensity. Muon and electron densities at the same observation point are also compared

Thematic Analysis: Exploring Practitioners' Perspectives of Delivering Animal Assisted Therapy

Animal Assisted Therapy (AAT) is a psychotherapeutic approach that uses animals in a therapeutic capacity and can be used as an adjunct with a range of practices such as different psychotherapeutic modalities. Despite its relatively long history, more robust research is needed to increase AAT’s evidence-base. There is a relative lack of research in AAT practice from a practitioners’ perspectives. The aim of this qualitative study was to explore how practitioners use AAT in their clinical practice. Ten participants were interviewed about their experiences of using AAT in their clinical practice. Thematic analysis was used to analyse the data. Three main themes emerged from the analysis: The Psychotherapeutic Encounter, Multi-Faceted Relational Process, and Challenges and Opportunities in AAT. The findings revealed that practitioners who used AAT utilised features of the therapy animal, with elements of nature and incorporated it into working in the moment. In addition, the findings revealed the relational dynamics between the client-animal, practitioner-animal, and that AAT is more than a dual therapeutic relationship. The findings also revealed the challenges and opportunities of using AAT within psychotherapy. The study has implications in the areas of better understanding and enhancing the therapeutic relationship in AAT, integrating AAT into counselling psychology practice and identifying potential areas for future research