The Effects of Vortex Generator Types on Heat Transfer and Flow Structure in a Rectangular Duct Flows

In this numerical study a detailed evaluation of the heat transfer characteristics and flow structure in a laminar and turbulent flow through a rectangular channel containing built-in of different type vortex generator has been a accomplished in a range of Reynolds number between 500 and 100,000.A modified version of ESCEAT code has been used to solve Navier-Stokes and energy equations. The purpose of this paper is to present numerical comparisons in terms of temperature, Nusselt number and flow patterns on several configurations of longitudinal vortex generator including new five cases. The structures of heat and flow were studied, using iso-contours of velocity components, vortices, temperature and Nusselt number. This study shows that the predicted structures of fluid flow, temperature fields and Nusselt number variation are strongly affected by the presence of the turbulators. Staggered arrangement gains high Nusselt number, also the lower and upper arrangements have higher Nusselt number than plane duct. High Reynolds number (higher air inlet velocity) will enhance the Nusselt number. Increase in ribs height will enhance the heat transfer as it works as surface area and turbulator at the same time

Thermodynamics of charged and rotating black strings

We study thermodynamics of cylindrically symmetric black holes. Uncharged as well as charged and rotating objects have been discussed. We derive surface gravity and hence the Hawking temperature and entropy for all these cases. We correct some results in the literature and present new ones. It is seen that thermodynamically these black configurations behave differently from spherically symmetric objects

Neurohypophysial dysmorphogenesis in mice lacking the homeobox gene Uncx4·1

Abstract A number of transcription factors have been implicated in the development of the hypothalamo-neurohypophysial system (HNS). Null mutations for these factors caused severe defects in proliferation, migration and survival during early embryogenesis. While they have informed about early events of HNS developments no insights in mechanisms of late development and maturation of this major peptidergic system have been obtained as yet. In a screen for adult-expressed homeobox genes we identified Uncx4.1 as a gene expressed in adult and embryonic magnocellular neurons of the (HNS). Null mutation of Uncx4.1 left these neurons viable and able to express neuropeptides. However, the connectivity of magnocellular neurons with posterior pituitary elements was compromised. As a consequence neuronal fibres traversed to the adenohypophysis. The penetrance of this phenotype was about 50%. The data show a selective role of Uncx4.1 in controlling the development of connections of hypothalamic neurons to pituitary elements, allowing central neurons to reach the peripheral blood circulation and to deliver hormones for control of peripheral functions

Diffractive Meson Production and the Quark-Pomeron Coupling

Diffractive meson production at HERA offers interesting possibilities to investigate diffractive processes and thus to learn something about the properties of the pomeron. The most succesful phenomenological description of the pomeron so far assumes it to couple like a $C = +1$ isoscalar photon to single quarks. This coupling leads, however, to problems for exclusive diffractive reactions. We propose a new phenomenological pomeron vertex, which leads to very good fits to the known data, but avoids the problems of the old vertex.Comment: 20 pages, latex with uuencoded postscript, revised versio

Production of vector mesons by real and virtual photons at high energies

A model based on Reggeon field theory is used for the description of the photo- and electroproduction of vector mesons ($\rho^0, \omega, \phi, J /\psi$) on the proton. Its main feature is the dependence of the Pomeron intercept on the virtuality of the photon. The few parameters of the model were determined by fitting the total cross sections for real and virtual photons on the proton. This allows a parameter-free description of the energy dependence of vector meson production. Very good agreement with the existing high energy data is obtained.Comment: 6 pages and 3 figures included in a uuencoded fil

Articular contact in a three-dimensional model of the knee

This study is aimed at the analysis of articular contact in a three-dimensional mathematical model of the human knee-joint. In particular the effect of articular contact on the passive motion characteristics is assessed in relation to experimentally obtained joint kinematics. Two basically different mathematical contact descriptions were compared for this purpose. One description was for rigid contact and one for deformable contact. The description of deformable contact is based on a simplified theory for contact of a thin elastic layer on a rigid foundation. The articular cartilage was described either as a linear elastic material or as a non-linear elastic material. The contact descriptions were introduced in a mathematical model of the knee. The locations of the ligament insertions and the geometry of the articular surfaces were obtained from a joint specimen of which experimentally determined kinematic data were available, and were used as input for the model. The ligaments were described by non-linear elastic line elements. The mechanical properties of the ligaments and the articular cartilage were derived from literature data. Parametric model evaluations showed that, relative to rigid articular contact, the incorporation of deformable contact did not alter the motion characteristics in a qualitative sense, and that the quantitative changes were small. Variation of the elasticity of the elastic layer revealed that decreasing the surface stiffness caused the ligaments to relax and, as a consequence, increased the joint laxity, particularly for axial rotation. The difference between the linear and the non-linear deformable contact in the knee model was very small for moderate loading conditions. The motion characteristics simulated with the knee model compared very well with the experiments. It is concluded that for simulation of the passive motion characteristics of the knee, the simplified description for contact of a thin linear elastic layer on a rigid foundation is a valid approach when aiming at the study of the motion characteristics for moderate loading conditions. With deformable contact in the knee model, geometric conformity between the surfaces can be modelled as opposed to rigid contact which assumed only point contact

Prospects and constraints on utilization of Jatropha curcas seeds in animal feedstuff

Combined physical, chemical and biochemical methods were used to process virgin seed meal of Jatropha curcas L. into treated Jatropha Seed Meal (JSM). Graded levels (0, 5, 10, 15, 20 and 25%) JSM treated by the various methods was included in the test diets which were fed ad libitum to 360 albino rats for a month in a single factor design trial. The results revealed that feed intake was numerically highest (p > 0.05) for the rats on the 5 % treated JSM diet, while feed efficiency was highest (p > 0.05) for those on the 10 % treated JSM diets. Weight gain was significantly highest (p< 0.05) for the rats on 10 and 15 % treated JSM diets. Lowest survival rate (17%) was observed on treated JSM diet processed by boiling, roasting followed by fermenting. Biochemical indices measured on treated JSM based diets were comparable with those obtained on the conventional diet (p > 0.05) except for blood cholesterol level (p < 0.05) which was elevated with increasing treated JSM in diets. There were also no significant differences recorded on AST and ALP activities (p > 0.05) between the treatments. Haematological indices investigated including PCV, RBC, Hb were insignificantly influenced by the 5% dietary treated JSM compared with the control diet (p > 0.05) and there was non-significant effect of the dietary treatment on the WBC differential counts of lymphocytes, eosinophils, monocytes and neutrophils. It was established in this study that inclusion of 5% treated JSM in diets had no detrimental effect on albino rats. Further researches are in progress to investigate inclusion of the treated JSM in diets at levels higher than the 5% used in this study.Keywords: JSM, Cockerels, Performance, Biochemical and haematological parameter

Antifungal susceptibility profile of yeast isolates from sterile sites at a tertiary hospital in South Africa

Invasive infections caused by yeasts are associated with high mortality and morbidity, and resistance to antifungal agents is increasing. Candida spp. has emerged as the leading cause of systemic nosocomial fungal infections. The aim of this study was to identify yeast isolates from sterile site specimens to species level, and to determine their susceptibility to fluconazole and voriconazole, at the National Health Laboratory, Service Dr George Mukhari Tertiary Laboratory from March to August 2007. Candida isolates were identified to species level using a germ tube test and/or Api® ID 32C kits. Antifungal susceptibility testing to fluconazole and voriconazole was performed using the disc diffusion method in accordance with the Clinical and Laboratory Standards Institute guidelines. All of the Candida isolates were from the neonatal intensive care unit (NICU), with the exception of two. The distribution of yeast isolates was as follows: C. krusei (41.9%), C. albicans (32.3%), C. inconspicua (5.5%), C. parapsilosis (2%), C. tropicalis (1.5%), C. sake (1.5%), C. lambica (1.5%), and C. valida (0.5%). Cryptococcus neoformans (11%), C. albidus (0.5%), Rhodotorula glutinis (1%), and C. humicola (0.5%) were also isolated. Of the isolated C. albicans, 61% were susceptible to fluconazole. A possible C. krusei outbreak could have occurred in the NICU during the study period. Voriconazole was the most susceptible antifungal agent to various yeast pathogens. The results of this study on azoles susceptibility testing of yeasts show that voriconazole may prove to be a valuable alternative antifungal agent in this tertiary hospital for the treatment of infections caused by yeasts, including Candida spp.http://www.sajei.co.za/index.php/SAJEI 2312-0053hb201

Characterization and classification of the microporosity in the unconventional carbonate reservoirs: A case study from Hanifa Formation, Jafurah Basin, Saudi Arabia

Formation porosity is a key factor that exerts substantial control upon reserve estimates, and ultimately may affect the development viability of unconventional resources. Microporosity studies have largely focused on siliciclastic mudstones, with limited examples that assess porosity type and distribution in organic-rich calcareous mudstone successions. In this work, a comprehensive porosity characterization study was performed on the organic-rich carbonate-dominated Hanifa Formation of the Jafurah Basin, which is the largest unconventional basin in Saudi Arabia. An extensive experimental program, involving petrographical description, SEM analysis, mineralogical analysis using XRD and QEMSCAN, and geochemistry analysis was employed in order to characterize the samples and analyze the geological origins of the microporosity. The main constituent minerals in this study are calcite (87 wt%) and anhydrite (9 wt%), as well as 85%. Fundamentally, the findings of this study demonstrate that the Hanifa Formation in the Jafurah Basin has the potential for gas exploration and recovery

Sporting embodiment: sports studies and the (continuing) promise of phenomenology

Whilst in recent years sports studies have addressed the calls ‘to bring the body back in’ to theorisations of sport and physical activity, the ‘promise of phenomenology’ remains largely under-realised with regard to sporting embodiment. Relatively few accounts are grounded in the ‘flesh’ of the lived sporting body, and phenomenology offers a powerful framework for such analysis. A wide-ranging, multi-stranded, and interpretatively contested perspective, phenomenology in general has been taken up and utilised in very different ways within different disciplinary fields. The purpose of this article is to consider some selected phenomenological threads, key qualities of the phenomenological method, and the potential for existentialist phenomenology in particular to contribute fresh perspectives to the sociological study of embodiment in sport and exercise. It offers one way to convey the ‘essences’, corporeal immediacy and textured sensuosity of the lived sporting body. The use of Interpretative Phenomenological Analysis (IPA) is also critically addressed. Key words: phenomenology; existentialist phenomenology; interpretative phenomenological analysis (IPA); sporting embodiment; the lived-body; Merleau-Pont