Developing a framework for critiquing health research

A new framework for critiquing health-related research is presented in this article. More commonly used existing frameworks tend to have been formulated within the quantitative research paradigm. While frameworks for critiquing qualitative research exist, they are often complex and more suited to the needs of students engaged in advanced levels of study. The framework presented in this article addresses both quantitative and qualitative research within one list of questions. It is argued that this assists the ‘novice’ student of nursing and health-related research with learning about the two approaches to research by giving consideration to aspects of the research process that are common to both approaches and also that differ between quantitative and qualitative research

Involving users in service planning: a focus group approach

This paper outlines the way in which a focus group approach was used to involve service users in the possible reconfiguration of follow-up services for breast cancer patients at a North London hospital. The focus group was used to identify the priority issues for users and the development of an objective questionnaire, to survey all current service users. Within the National Health Service (NHS) the concept of user involvement has been embodied in contemporary health policy, and has become an important constituent of current policy direction. This study was the first stage of a larger stakeholder project that aimed to involve service users and clinicians in developing a new model of breast cancer follow-up service. From the focus group emerged five key themes around breast cancer follow up. They were: • The need for reassurance after the diagnosis of cancer. • Continuity of care. • Privacy and dignity and other elements of the examination technique. • Information and the detection of new symptoms. • The opportunity to discuss feelings and worries. In this paper, the nature of breast cancer follow-up services is outlined, and the difficulties associated with such services are discussed. The background to user involvement within the United Kingdom is explored, and the strategies that have previously been used are considered. The practical issues involved in using the focus group approach are examined, and the experience of using such an approach is outlined in this study. The involvement of service users as a key stakeholder in the process of planning change, through a participatory research strategy, ensured that their voices were heard alongside those of both hospital and primary care staff

Residential solar air conditioning: Energy and Exergy analyses of an ammonia-water absorption cooling system

Large scale heat-driven absorption cooling systems are available in the marketplace for industrial applications but the concept of a solar driven absorption chiller for air-conditioning applications is relatively new. Absorption chillers have a lower efficiency than compression refrigeration systems, when used for small scale applications and this restrains the absorption cooling system from air conditioning applications in residential buildings. The potential of a solar driven ammonia-water absorption chiller for residential air conditioning application is discussed and analyzed in this paper. A thermodynamic model has been developed based on a 10 kW air cooled ammonia-water absorption chiller driven by solar thermal energy. Both energy and exergy analyses have been conducted to evaluate the performance of this residential scale cooling system. The analyses uncovered that the absorber is where the most exergy loss occurs (63%) followed by the generator (13%) and the condenser (11%). Furthermore, the exergy loss of the condenser and absorber greatly increase with temperature, the generator less so, and the exergy loss in the evaporator is the least sensitive to increasing temperature

Gas Kinematics and Excitation in the Filamentary IRDC G035.39-00.33

Some theories of dense molecular cloud formation involve dynamical environments driven by converging atomic flows or collisions between preexisting molecular clouds. The determination of the dynamics and physical conditions of the gas in clouds at the early stages of their evolution is essential to establish the dynamical imprints of such collisions, and to infer the processes involved in their formation. We present multi-transition 13CO and C18O maps toward the IRDC G035.39-00.33, believed to be at the earliest stages of evolution. The 13CO and C18O gas is distributed in three filaments (Filaments 1, 2 and 3), where the most massive cores are preferentially found at the intersecting regions between them. The filaments have a similar kinematic structure with smooth velocity gradients of ~0.4-0.8 km s-1 pc-1. Several scenarios are proposed to explain these gradients, including cloud rotation, gas accretion along the filaments, global gravitational collapse, and unresolved sub-filament structures. These results are complemented by HCO+, HNC, H13CO+ and HN13C single-pointing data to search for gas infall signatures. The 13CO and C18O gas motions are supersonic across G035.39-00.33, with the emission showing broader linewidths toward the edges of the IRDC. This could be due to energy dissipation at the densest regions in the cloud. The average H2 densities are ~5000-7000 cm-3, with Filaments 2 and 3 being denser and more massive than Filament 1. The C18O data unveils three regions with high CO depletion factors (f_D~5-12), similar to those found in massive starless cores.Comment: 20 pages, 14 figures, 6 tables, accepted for publication in MNRA

Energy efficiency and economic feasibility of an absorption air-conditioning system using wet, dry and hybrid heat rejection methods

In tropical and sub-tropical regions, air-conditioning systems account for the greatest electricity consumption and high water use. Solar-driven absorption cooling systems can conveniently reduce electricity consumption at need. The performance of this cooling system depends on the system’s heat rejection. A simulation was performed for a 15 kW single effect ammonia-water absorption cooling system driven by low temperature thermal energy and with three different heat rejection methods (wet cooling, dry cooling, and hybrid cooling). This hybrid cooling system uses wet cooling on the absorber and dry cooling on the condenser. The system performance and economics of the chiller with these cooling methods were evaluated. The analysis showed that a wet cooling system has a higher system performance and water consumption compared to a dry cooling system, which has a high primary energy consumption with no water usage. In hot weather conditions and where there is scarcity of water, hybrid cooling can consume on average 41% less electrical energy than dry cooling and 49% less water than wet cooling and the payback period compared to a wet cooling system can be less than three years

Bubble-pump-driven LiBr-H2O and LiCl-H2O Absorption Air-Conditioning Systems

A thermally-driven bubble pump, powered by solar or waste heat energy, is a simple and efficient technique for lifting a liquid from lower to higher levels, after which it can flow by gravity. In this study, solar thermal driven pumps were incorporated in the solar collector as well as in the refrigerant cycle to provide a design of an air-conditioning system for a residential home that is independent of grid electricity. The crystallization challenge, low pressure, and low efficiency are the main downsides of bubble-pump-driven LiBr-H2O refrigeration systems, in comparison with other bubble-pump-driven diffusion absorption refrigeration systems. Therefore, a complete thermodynamic analysis of each component is necessary to improve the system performance. In this research, a thermodynamic model was developed, introducing a new absorbent-refrigerant pair (LiCl-H2O) and comparing it with LiBr-H2O, in a bubble pump operated absorption chiller driven by solar thermal energy. Under the same operating condition, the highest cooling effect and the performance of the LiCl-H2O system are 49 W and COP=0.56 compared to 34 W and COP=0.46 for a LiBr-H2O system

Overture - Object-oriented tools for overset grid applications

The Overture framework is an object-oriented environment for solving partial differential equations in two and three space dimensions. It is a collection of C++ libraries that enables the use of finite difference and finite volume methods at a level that hides the details of the associated data structures. Overture can be used to solve problems in complicated, moving geometries using the method of overlapping grids. It has support for grid generation, difference operators, boundary conditions, data-base access and graphics. Short sample code segments are presented to show the power of this approach

Advanced Exergy Analysis Of Licl-H2O Absorption Air Conditioning System

Increasing energy demand for air conditioning due to climate change is posing a continuous threat to the environment. Absorption air-conditioning systems driven by solar thermal or waste heat energy are an alternative for providing cooling comfort in a sustainable manner. The crystallization problem of high performance LiBr-H2O absorption cooling system hinders its small-scale applications. In this study, the potential of a 10 kW LiCl-H2O absorption refrigeration system is discussed and analyzed. The new concept of advanced exergy analysis is coupled with conventional thermodynamic analyses, which provides the available potential of each component for overall system performance improvement. The analyses uncovered that only 45% of the total exergy loss is due to each component’s own internal irreversibilities, whereas the remaining is through the interaction of the irreversibilities of other components in the system. The analyses also reveal that 43% of the total exergy loss is unavoidable and 57% can be reduced by improving the overall system efficiency

Tracer concentration profiles measured in central London as part of the REPARTEE campaign

There have been relatively few tracer experiments carried out that have looked at vertical plume spread in urban areas. In this paper we present results from two tracer (cyclic perfluorocarbon) experiments carried out in 2006 and 2007 in central London centred on the BT Tower as part of the REPARTEE (Regent’s Park and Tower Environmental Experiment) campaign. The height of the tower gives a unique opportunity to study vertical dispersion profiles and transport times in central London. Vertical gradients are contrasted with the relevant Pasquill stability classes. Estimation of lateral advection and vertical mixing times are made and compared with previous measurements. Data are then compared with a simple operational dispersion model and contrasted with data taken in central London as part of the DAPPLE campaign. This correlates dosage with non-dimensionalised distance from source. Such analyses illustrate the feasibility of the use of these empirical correlations over these prescribed distances in central London