23 research outputs found

    Numerical investigation on the performance of the helical and conical coil heat exchanger configuration in the dynamic mode of heat extraction

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    . Owing to the high heat transfer performance, compact design and large surface area per unit volume, the curved and helical circular tubes have many applications such as heating, refrigeration, air conditioning, steam generation, heat extraction etc. One of the ways to improve the performance of water heating systems is to enhance the performance of immersed heat exchanger. In solar heating systems, immersed heat exchangers of curved shape are used to charge and discharge sensible heat water storage tanks. Effect of arrangement and position of the tubes, geometry of coil, configuration, shape, flow rate, type of working fluid, Reynolds number associated with flow, and inlet temperature to coil, on the performance of storage systems have been studied in the literature. Rate of discharge, heat transfer coefficient, effectiveness of heat exchanger, heat transfer rate, discharging efficiency and increment in temperature of outlet fluid are the standard performance parameters to evaluate the heat transfer and fluid flow phenomenon in the curved tubes. Heat transfer characteristics are investigated and analyzed for one helical and two conical coil (conical and inverted conical) configurations using a three-dimensional unsteady numerical model. The numerical model is validated against reported experimental result and a good agreement is found. For the same length of the coil, the inverted conical configuration presents more heat transfer surface area to the incoming hot fluid entering the thermal energy storage tank, as compared to conical coil and helical coil configurations, leading to higher extraction of thermal energy. Based on the performance parameters, inverted conical coil experiences enhanced heat transfer, high overall heat transfer coefficient and better effectiveness of heat exchanger as compared to helical and conical coil configurations

    A Comprehensive Review on Equine Influenza Virus:Etiology, Epidemiology, Pathobiology, Advances in Developing Diagnostics, Vaccines, and Control Strategies

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    Among all the emerging and re-emerging animal diseases, influenza group is the prototype member associated with severe respiratory infections in wide host species. Wherein, Equine influenza (EI) is the main cause of respiratory illness in equines across globe and is caused by equine influenza A virus (EIV-A) which has impacted the equine industry internationally due to high morbidity and marginal morality. The virus transmits easily by direct contact and inhalation making its spread global and leaving only limited areas untouched. Hitherto reports confirm that this virus crosses the species barriers and found to affect canines and few other animal species (cat and camel). EIV is continuously evolving with changes at the amino acid level wreaking the control program a tedious task. Until now, no natural EI origin infections have been reported explicitly in humans. Recent advances in the diagnostics have led to efficient surveillance and rapid detection of EIV infections at the onset of outbreaks. Incessant surveillance programs will aid in opting a better control strategy for this virus by updating the circulating vaccine strains. Recurrent vaccination failures against this virus due to antigenic drift and shift have been disappointing, however better understanding of the virus pathogenesis would make it easier to design effective vaccines predominantly targeting the conserved epitopes (HA glycoprotein). Additionally, the cold adapted and canarypox vectored vaccines are proving effective in ceasing the severity of disease. Furthermore, better understanding of its genetics and molecular biology will help in estimating the rate of evolution and occurrence of pandemics in future. Here, we highlight the advances occurred in understanding the etiology, epidemiology and pathobiology of EIV and a special focus is on designing and developing effective diagnostics, vaccines and control strategies for mitigating the emerging menace by EIV

    Serosurveillance for Japanese encephalitis virus infection among equines in India

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    The seroprevalence of Japanese encephalitis virus (JEV) among equines was evaluated from January 2006 to December 2009 in 13 different states of India by hemagglutination inhibition (HI) test and virus neutralization test (VNT). Antibodies against JEV were detected in 327 out of 3,286 (10%) equines with a maximum prevalence reported in the state of Manipur (91.7%) followed by Gujarat (18.5%), Madhya Pradesh (14.4%), and Uttar Pradesh (11.6%). Evidence of JEV infection was observed in equines in Indore (Madhya Pradesh) where a 4-fold or higher rise in antibody titer was observed in 21 out of 34 horses in November 2007 to October 2006. In March 2008, seven of these horses had a subsequent 4-fold rise in JEV antibody titers while this titer decreased in nine animals. JEV-positive horse sera had a JEV/WNV (West Nile virus) ratio over 2.0 according to the HI and/or VNT. These results indicated that JEV is endemic among equines in India

    Experimental investigation of heat dispatch controllability through simultaneous charging-discharging and stand alone- discharging opeations in vertical cylindrical heat storage tank

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    Using a vertical cylindrical thermal energy storage (TES) tank with helical discharging coil fitted inside, the present study experimentally investigates the scarcely studied simultaneous charging and discharging (SCAD) mode, as well as the discharging-alone operation following a substantial stand-alone period. The temperature distributions within the tank, coil outlet temperature and primary thermocline thickness serve as the key performance trackers for the storage tank. The primary thermocline thickness increases with increasing coil side flow rate during the SCAD operation. The SCAD operation exhibited the splitting of the primary thermocline, leading to the formation of a secondary thermocline in the lower half of the tank. The sustenance of secondary thermocline, thermal gradients across the tank height, and the discharging efficiency are found to decrease with increasing charging flow rate, whereas the coil outlet temperature and the primary thermocline thickness increase. The highest average discharging efficiency of 80.1 % is observed for the TES charging at 0.5 L/min at 70 °C, accompanied by the 2 L/min discharging flow rate. The average thermal energy stored is the maximum (1758 kJ) for the TES charging at 1.25 L/min at 70 °C, with discharging rate of 0.5 L/min. The stand-alone period prior to the discharging-alone operation exhibits the heat content retention capability of the storage and allows for the thermocline formation. The time required for thermal stratification is more with the higher initial charging temperature. The time required for the complete discharging of the TES storage tank decreases with increasing coil-side flow rate. These modes provide ample operational flexibility and heat content dispatch controllability, resulting in the versatility of the system

    Response Surface Methodology-based Prediction Model for Working Fluid Temperature during Stand-Alone Operation of Vertical Cylindrical Thermal Energy Storage Tank

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    Domestic hot water applications rely on the stand-alone operation of thermal energy storage (TES), in which natural convection significantly affects the efficiency of a storage system. The present study develops a two-dimensional axisymmetric numerical model for detailed simulation. Subsequently, an effective prediction model for a vertical stand-alone cylindrical storage tank is formed. The results of the detailed model are found to have good agreement with the findings of the in-house experiments. The experimental and numerical results show the formation of temperature gradients with time, known as thermal stratification, which affects the storage efficiency and thermodynamic quality of the stored heat. A seven parameter three-level Box-Behnken Design (BBD) Response Surface Methodology (RSM) is used to develop a prediction model for the working fluid temperature inside the tank. Analysis of variance (ANOVA) is performed to evaluate the effects and interactions of the process parameters for selecting the statistically significant terms. Based on the ANOVA, a reduced prediction equation is generated. Various plots such as normal probability, predicted versus actual response, versus fits, versus order, Pareto charts, main effects and interaction effects are created to analyze the model. Comparing the results of the detailed model and prediction equation, it is concluded that the newly formulated scaling-based prediction equation can predict and characterize the performance of the TES under test with adequate accuracy

    Thermal stratification characteristics during simultaneous charging and discharging for different storage tank geometries with immersed discharging coil

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    The geometrical shapes of the thermal energy storage and the configurations of immersed discharging coils dictate the efficacy of low-to-medium temperature hot water applications. This study uses a three-dimensional numerical model to investigate the thermal characteristics of three storage configurations for simultaneous charging and discharging. The same tank volume and height, as well as the same coil tube dimensions, are considered for three different configurations - cylindrical tank with a helical discharging coil, as well as circular truncated cone-shaped and paraboloidal tanks with conical discharging coils. The discharging flow rate is varied for a deeper understanding of the realistic interplay between energy demand and supply. Results obtained for the cylindrical tank are found to have good agreement with the observations from the in-house experiments. The energy stored, discharging coil outlet temperature, and the extent of thermal stratification decrease with increasing coil flow rate, whilst discharging efficiency and primary thermocline thickness increase. The paraboloidal tank equipped with a conical discharging coil exhibited the highest cumulative energy stored (8821 kJ) just before the commencement of dynamic dual operation, owing to the minimal thermal losses attributable to the lowest surface-area-to-volume ratio. Thermocline thickness is found to expand with time for all the cases, and the highest thermocline thickness expansion rate of 0.208 mm/s is found for the cylindrical tank indicating a higher degree of energy degradation. The peak values for the cumulative energy discharged (9788 kJ), and average discharging efficiency (0.36) occurred for the paraboloidal tank with the conical discharging coil configuration. Based on the detailed analyses, the paraboloidal storage tank configuration is found to exhibit better system reliability and energy management, leading to more efficient heat dispatch controllability due to the enhanced energy harnessing features

    Development, evaluation, and laboratory validation of immunoassays for the diagnosis of equine infectious anemia (EIA) using recombinant protein produced from a synthetic p26 gene of EIA virus

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    Not AvailableEquine infectious anemia (EIA)—a retroviral disease caused by equine infectious anemia virus (EIAV)— is a chronic, debilitating disease of horses, mules, and donkeys. EIAV infection has been reported worldwide and is recognized as pathogen of significant economic importance to the horse industry. This disease falls under regulatory control program in many countries including India. Control of EIA is based on identification of inapparent carriers by detection of antibodies to EIAV in serologic tests and ‘‘Stamping Out’’ policy. The current internationally accepted test for diagnosis of EIA is the agar gel immune-diffusion test (AGID), which detects antibodies to the major gag gene (p26) product. The objective of this study was to develop recombinant p26 based in-house immunoassays [enzyme linked immunosorbent assays (ELISA), and AGID] for EIA diagnosis. The synthetic p26 gene of EIAV was expressed in Escherichia coli and diagnostic potential of recombinant p26 protein were evaluated in ELISA and AGID on 7,150 and 1,200 equine serum samples, respectively, and compared with commercial standard AGID kit. The relative sensitivity and specificity of the newly developed ELISA were 100 and 98.6 %, respectively. Whereas, relative sensitivity and specificity of the newly developed AGID were in complete agreement in respect to commercial AGID kit. Here, we have reported the validation of an ELISA and AGID on large number of equine serum samples using recombinant p26 protein produced from synthetic gene which does not require handling of pathogenic EIAV. Since the indigenously developed reagents would be economical than commercial diagnostic kit, the rp26 basedimmunoassays could be adopted for the sero-diagnosis and control of EIA in India.ICA

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    Not AvailableNine members of the family Herpesviridae infect equines and two of them (EHV1 and EHV4) are the globally significant pathogens causing respiratory disease, abortion and more rarely paralysis. The ability of equid herpesviruses to establish life-long latent infection in lymphoid and neural tissues with periodic reactivation and shedding is central to the maintenance of these viruses in horse populations. Over 50% of horses become latently infected after infection with EHV1 and EHV4. During latency, expression of viral genes is highly restricted with expression of few or no viral proteins. The recent scientific advances have provided insight into the mechanism of equine herpesvirus pathogenesis, including latency. The establishment of latent infection is highly coordinated process regulated by inter-play of viral, host and environmental factors. In this article, we review how molecular, cellular and viral regulatory mechanisms influence the switch between latent and lytic infections.Not Availabl

    Optimization and Validation of Indirect ELISA Using Truncated TssB Protein for the Serodiagnosis of Glanders amongst Equines

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    Objective. To express truncated TssB protein of Burkholderia mallei and to evaluate its diagnostic efficacy for serological detection of glanders among equines. Materials and Methods. In an attempt to develop recombinant protein based enzyme-linked immunosorbent assay (ELISA), N-terminal 200 amino acid sequences of B. mallei TssB protein—a type 6 secretory effector protein—were expressed in prokaryotic expression system. Diagnostic potential of recombinant TssB protein was evaluated in indirect ELISA using a panel of glanders positive (n=49), negative (n=30), and field serum samples (n=1811). Cross-reactivity of the assay was assessed with equine disease control serum and human melioidosis positive serum. Results. In comparison to CFT, diagnostic sensitivity and specificity of ELISA were 99.7% and 100%, respectively. Conclusions. The indirect ELISA method using the truncated TssB offered safer and more rapid and efficient means of serodiagnosis of glanders in equines. These data highlight the use of TssB as potential diagnostic antigen for serological diagnosis of glanders
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