Hawking radiation of scalar particles from accelerating and rotating black holes

Hawking radiation of uncharged and charged scalars from accelerating and rotating black holes is studied. We calculate the tunneling probabilities of these particles from the rotation and acceleration horizons of these black holes. Using the tunneling method we recover the correct Hawking temperature as well

Ureteral stent placement increases the risk for developing BK viremia after kidney transplantation.

The placement of ureteral stent (UrSt) at kidney transplantation reduces major urological complications but increases the risk for developing nephropathy from the BK virus. It is unclear whether UrSt placement increases nephropathy risk by increasing risk of precursor viral replication or by other mechanisms. We retrospectively investigated whether UrSt placement increased the risk for developing BK Viremia (BKVM) in adult and pediatric kidney transplants performed at the University of Florida between July 1, 2007, and December 31, 2010. In this period all recipients underwent prospective BKV PCR monitoring and were maintained on similar immunosuppression. Stent placement or not was based on surgeon preference. In 621 transplants, UrSt were placed in 295 (47.5%). BKVM was seen in 22% versus 16% without UrSt (P=0.05). In multivariate analyses, adjusting for multiple transplant covariates, only UrSt placement remained significantly associated with BKVM (P=0.04). UrSt placement significantly increased the risk for BKVM. Routine UrSt placement needs to be revaluated, since benefits may be negated by the need for more BK PCR testing and potential for graft survival-affecting nephritis

Hawking temperature of rotating charged black strings from tunneling

Thermal radiations from spherically symmetric black holes have been studied from the point of view of quantum tunneling. In this paper we extend this approach to study radiation of fermions from charged and rotating black strings. Using WKB approximation and Hamilton-Jacobi method we work out the tunneling probabilities of incoming and outgoing fermions and find the correct Hawking temperature for these objects. We show that in appropriate limits the results reduce to those for the uncharged and non-rotating black strings

Influence of coolant temperature on the performance of a four stroke spark ignition engine employing a dual circuit cooling system

Diesel engines have attracted attention because of their higher thermal efficiency and lower carbon dioxide emissions than gasoline engines.  On the other hand, oxides of nitrogen (NOx) and particulate matter (PM) in the exhaust from diesel engines are difficult to be reduced simultaneously because a decrease in one is likely to result in an increase in the other.  In this paper, an attempt has been made to compare the effect of the heat lost to the coolant in the cylinder block, and in the cylinder head with a conventional cooling circuit with corresponding effects in an engine with a dual cooling circuit.  A dual cooling circuit employs separate cooling circuits for the cylinder block, and for the cylinder head.  A single cylinder, four-stroke, water cooled, naturally aspirated spark ignition engine test rig was developed for the purpose.  The influences of the cylinder block and cylinder head temperatures on brake specific fuel consumption (bsfc) and on exhaust emissions were measured.  The results show that raising the temperature of the coolant in the engine block can produce significant improvements in bsfc with a corresponding reduction in the hydrocarbon (HC) emissions.  Similarly, lowering the coolant temperature in the cylinder head can increase the knock limit of the engine with a corresponding reduction in the levels of NOx in the exhaust emissions.   The objective of this investigation was to access the magnitude of the likely benefits of the dual circuit cooling system.Keywords: dual circuit cooling system, spark ignition engine, heat transfer, engine cooling Citation: Rehman A., R. M. Sarviya, S. Dixit, and R. K. Pandey.  Influence of coolant temperature on the performance of a four stroke spark ignition engine employing a dual circuit cooling system.  Agric Eng Int: CIGR Journal, 2010, 12(1): 84-90.&nbsp

Influence of Tillage and Mulch on Soil Physical Properties and Wheat Yield in Rice-Wheat System

Zero tillage along with application of mulch is an important strategy for soil conservation which maintains sustainability of agricultural system. A randomized complete block design in a split plot arrangement was used with four tillage methods [conventional tillage, (CT); deep tillage, (DT); zero tillage with zone disc tiller, (ZDT); and happy seeder, (HS)] in main plots and five mulch materials [no mulch, (M0); rice straw, (MRice); wheat straw, (MWheat); plastic sheet, (MPlastic) at 4 t ha-1, and natural mulch, (MNatural)] in subplots during 2009-10 and 2010-11. Results showed that DT significantly decreased soil bulk density, penetration resistance, and volumetric moisture content when compared with CT, ZDT, and HS. However, wheat yield parameters such as germination count, fertile tillers, grain yield and water use efficiency were significantly higher in HS compared with other tillage treatments while root length and grain protein were higher in DT. Plant height remained non-significant during 2009-10, while in 2010-11 it differed significantly and was higher in HS than other tillage treatments. Wheat yield parameters were significantly higher in MPlastic at 4 t ha-1 than other mulch materials. Happy seeder and deep tillage along with plastic mulch have positive impact on soil physical properties, root growth, water use efficiency and yield parameters by creating a favorable soil environment

Development of a Novel Bioactive Functionally Guided Tissue Graded Membrane for Periodontal Lesions

Periodontal disorders are chronic inflammatory condition of the supporting structures of the tooth. Guided tissue regeneration (GTR) membranes have been used in the management of destructive forms of periodontal disease as a means of aiding regeneration of lost supporting tissues, such as alveolar bone, cementum, gingiva and periodontal ligament. In this study, individual layers of a functionally graded bioactive composite membrane were fabricated using the techniques of solvent casting, freeze gelation and electrospinning by incorporating Hydroxyapatite (HA) alongside Chitosan and using acetic acid as the primary solvent. The techniques were simple, time /energy efficient and reproducible resulting in novel non porous and porous scaffolds with potential for use in periodontal tissue regeneration. Scaffolds were characterised in terms of ultra structure morphology by scanning electron microscopy, physiochemical properties, water uptake, and degradation by weight loss, mechanical properties and biocompatibility. Microscopy revealed porous features and presence of hydroxyapatite was confirmed with Fourier Transform Infrared (FTIR) spectroscopy. Morphology of the pores varied with different solvents, which were affected by addition of HA. Biocompatibility studies were carried out using a human osteosarcoma cell line and human embryonic stem cell-derived mesenchymal progenitor cells. All tested scaffolds showed increasing cell viability over the tested culture period. In conclusion, solvent casting, freeze gelation and electrospinning were successfully used to fabricate scaffolds with different morphology and porosity. Future work will focus on incorporation of drug into the core layer and combining the surface and core layers to form a spatially designed functionally graded biodegradable membrane with the potential of being used for periodontal tissue regeneration