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Conjugate heat transfer from a uniformly heated spinning solid disk of finite thickness and radius during a semi-confined liquid jet impingement from a rotating nozzle is studied. The model covers the entire fluid region including...
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Conjugate heat transfer from a uniformly heated spinning solid disk of finite thickness and radius during a semi-confined liquid jet impingement from a rotating nozzle is studied. The model covers the entire fluid region including the impinging jet on a flat circular disk and flow spreading out downstream under the spinning confinement plate and free surface flow after exposure to the ambient gaseous medium. The model examines how the heat transfer is affected by adding a secondary rotational flow under semi-confined jet impingement. The solution is made under steady state and laminar conditions. The study considered various plate materials such as aluminum, copper, silver, constantan and silicon. Ammonia, water, flouroinert FC-77 and MIL-7808 oil were used as working fluids. The range of parameters covered included Reynolds number (220-900), Ekman number (7.08 × 10~(-5)-∞), nozzle-to-target spacing (β = 0.25-1.0), disk thicknesses to nozzle diameter ratio (b/d_n = 0.25-1.67), Prandtl number (1.29-124.44) and solid to fluid thermal conductivity ratio (36.91-2222). It was found that a higher Reynolds number increased local heat transfer coefficient reducing the interface temperature difference over the entire disk surface. The rotational rate also increased local heat transfer coefficient under most conditions. An engineering correlation relating the Nusselt number with other dimensionless parameters was developed for the prediction of the system performance.
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The objective of this study is to characterize the conjugate heat transfer for a confined liquid jet impinging on a rotating and uniformly heated solid disk of finite thickness and radius. The model covers the entire fluid region ...
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The objective of this study is to characterize the conjugate heat transfer for a confined liquid jet impinging on a rotating and uniformly heated solid disk of finite thickness and radius. The model covers the entire fluid region (impinging jet and flow spreading out over the rotating surface) and the solid disk as a conjugate problem. Calculations were done for a number of disk materials and working fluids covering a range of Reynolds number (500-1500), under a broad rotational rate range of 0-750 rpm or Ekman number (4.42 x 10~(-5) to ∞), nozzle to target spacing (β = 0.25-5.0), disk thicknesses to nozzle diameter ratio (b/d_n = 0.167-1.67), Biot number (3.73 x 10~(-3)—0.118), Prandtl number (1.29-124.44), and solid to fluid thermal conductivity ratio (36.91-2222). It was found that plate materials with higher thermal conductivity maintained a more uniform temperature distribution at the solid-fluid interface. A higher Reynolds number increased the local heat transfer coefficient reducing the wall to fluid temperature difference over the entire interface. The rotational rate also increased local heat transfer coefficient under most conditions. The simulation results compared reasonably well with previous experimental studies.
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The present communication deals with synthesis of a new series of spiro-2-[3'-(2'-phenyl)-3H-indolyl]-1-aryl-3-phenylaziridines. Infrared (IR), ~1H nuclear magnetic resonance (NMR), mass spectral, and elemental analysis data corro...
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The present communication deals with synthesis of a new series of spiro-2-[3'-(2'-phenyl)-3H-indolyl]-1-aryl-3-phenylaziridines. Infrared (IR), ~1H nuclear magnetic resonance (NMR), mass spectral, and elemental analysis data corroborated the structure of all synthesized compounds. Synthesized compounds were screened for antimicrobial activity against a representative panel of Gram-positive and Gram-negative bacteria. All newly synthesized compounds showed remarkable antimicrobial behavior. Structure-activity relationship (SAR) investigations were applied to investigate the correlation between the molecular refractive index (M_R) parameter of the compounds and their biological activity profile. All compounds were subjected to acute toxicity studies to determine 50% lethal dose (LD_(50)) values.
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N-(4-Hydroxyphenyl)retinamide (4-HPR), a synthetic retinoid is under clinical evaluation as a therapeutic agent in a variety of cancers. Its mechanism(s) of action involves multiple overlapping pathways that still remain unclear. ...
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N-(4-Hydroxyphenyl)retinamide (4-HPR), a synthetic retinoid is under clinical evaluation as a therapeutic agent in a variety of cancers. Its mechanism(s) of action involves multiple overlapping pathways that still remain unclear. In glioma cells its mechanism of action is not well elucidated. Here, we show that 4-HPR and not all-trans retinoic acid and 9-cis retinoic acid effectively induce apoptosis in glioma cells. 4-HPR-induced apoptosis is associated with hydroperoxide production and loss of mitochondrial membrane potential (ΔΨm). Ultrastructural changes further indicate 4-HPR-induced mitochondrial swelling, endoplasmic reticulum (ER) dilation as well as close proximity of mitochondria and ER. As suggested by dilated ER, 4-HPR treatment increased the free cytosolic Ca2+ as well as mitochondrial Ca2+. Chelation of extracellular Ca2+ by EGTA did not prevent Ca2+ elevation, thus suggesting involvement of intracellular calcium stores in the release. Buffering of intracellular calcium by BAPTA-AM did not prevent 4-HPR-induced apoptosis; however, blocking the release of Ca2+ from ER by heparin inhibited apoptosis, indicating the role of depletion of Ca2+ from ER stores in apoptosis. 4-HPR treatment also resulted in an increase in Bax levels along with its translocation to mitochondria that promote mitochondrial membrane permeabilization. 4-HPR-induced apoptosis was further associated with the release of cytochrome c and apoptosis-inducing factor (AIF) from mitochondria to cytosol and nucleus, respectively, along with caspase-3 and caspase-7 activation. However, AIF nuclear translocation, peripheral chromatin condensation and apoptosis were not completely prevented by general caspase inhibitors, thus suggesting involvement of a caspase-dependent and caspase-independent pathway in 4-HPR-induced apoptosis. Taken together, these results suggest the role of mitochondrial-mediated pathway and ER stress as a key event in 4-HPR-induced apoptosis in glioma cells.
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Indoor air quality is one of the major environmental concerns as people spend about 90% of their time indoors and about 7% of their daily time commuting, mostly between their workplace and their residence [1]. Therefore, an unders...
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Indoor air quality is one of the major environmental concerns as people spend about 90% of their time indoors and about 7% of their daily time commuting, mostly between their workplace and their residence [1]. Therefore, an understanding of the factors affecting concentrations of indoor contaminants in public transport buses is important to study the impact on the passengers and driver. The various factors affecting the pollutant concentrations in an indoor environment are meteorology, indoor pollutant sources, ventilation settings, exhaust fumes, and outdoor pollutant sources. The indoor pollutants studied in this article are particu-late matter, carbon dioxide, carbon monoxide, sulphur dioxide, nitric oxide, and nitrogen dioxide.
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Productivity measurement is a required management tool in evaluating and monitoring the performance of a business operation. The purpose of this paper is to provide an analysis of the state-of-the-art research on productivity meas...
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Productivity measurement is a required management tool in evaluating and monitoring the performance of a business operation. The purpose of this paper is to provide an analysis of the state-of-the-art research on productivity measurement. The paper comprises two major section.
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As the global marketplace continues its relentless growth, ethical purchasing behavior assumes greater significance for both domestic and international firms. The primary purpose of this study was to assess the ethics of purchasin...
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As the global marketplace continues its relentless growth, ethical purchasing behavior assumes greater significance for both domestic and international firms. The primary purpose of this study was to assess the ethics of purchasing management professionals in India. A questionnaire, based on prior research, was developed by the authors for obtaining the information. AN analysis of data from 69 respondents indi- cated that the Indian purchasing managers reacted less ethically to questionable situations than has been reported in previous studies conducted in the United States.
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Constrained ansioropic dipole oscillator strength techniques are used to obtain reliable values for a wide range of anisotropic and isotropic dipole properties of NO, including most anisotropic components of the dipole-dipole disp...
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Constrained ansioropic dipole oscillator strength techniques are used to obtain reliable values for a wide range of anisotropic and isotropic dipole properties of NO, including most anisotropic components of the dipole-dipole dispersion energy coefficients for the interaction of NO with NO, O_2, H_2, CO, He, Ne, Ar, Kr and Xe. Some of the anisotropic constraints required for our calculations are obtained via dipole sum rules from ab initio, multi-reference configuration interaction wavefunctions for NO.
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The United States Environmental Protection Agency (EPA) developed Toxic Release Inventory (TRI) using information submitted by different industries in the United States. This research examines the contaminants released by paper ma...
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The United States Environmental Protection Agency (EPA) developed Toxic Release Inventory (TRI) using information submitted by different industries in the United States. This research examines the contaminants released by paper manufacturing industry in the United States and Ohio over time and what paper manufacturers are doing to diminish the quantities of chemical wastes generated, released to the environment, or managed by other means. It is understood that there is a reduction in the Risk-Screening Environmental Indicators (RSEI) scores from 2002 to 2014 in all the states, which can be related to the adaptation of recycling or reusing of the chemicals in various other manufacturing processes. The other significant observation inferred from the analysis is that the facilities in the states such as Wisconsin, Louisiana, South Carolina, Connecticut, and Pennsylvania based on the economic feasibility or recycling prospects, they are generating higher quantities of the selected chemical resulting in the higher RSEI scores respectively for the above-mentioned states. This article demonstrates the application of the risk-screening indicators model to a large database to analyze pollution data.
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Even though fiber reinforced polymer (FRP) composites are used in many applications, their integrity overtime is still unknown and remains a major concern. Due to inherent viscoelastic nature of polymers and their composites, expo...
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Even though fiber reinforced polymer (FRP) composites are used in many applications, their integrity overtime is still unknown and remains a major concern. Due to inherent viscoelastic nature of polymers and their composites, exposure to elevated temperature and moist conditions results in matrix cracking, plasticization, and interfacial debonding and so on resulting in premature failure of composite structures. Researcher have found that failure in environmentally exposed composites is mainly dominated by matrix whereas the effect on fiber is minimal. Recent advancement in polymeric nanocomposites has shown significant enhancement in mechanical and thermal properties with small weight % addition of nanoclay particles. Most of studies on modified polymeric composite have been carried out at room temperature and to the best of our knowledge no studies are performed under extreme/long-term conditions. Hence, an attempt is made in this work to study nanophased epoxy composites under accelerated ageing conditions. Epoxy resin was modified by incorporating nanoclay at different weight percentages using magnetic mixing method and then samples were prepared for various tests. The samples were subjected to hot (elevated temperature: dry, wet at 60 and 80 ℃) and cold (subzero: dry, wet, -18 ℃) conditions for 15,45 and 90 days, respectively. Moisture absorption kinetics, quasi-static flexure and micrographic studies were performed of these composites and compared with the samples aged at control conditions. Percentage weight increase was observed in all the wet conditioned samples with a maximum of 3.1% in neat and 2.1% in 2 wt% nanophased epoxy samples. Quasi-static characterization showed degradation in strength and modulus for all conditioned neat samples with a maximum decrease of 37% and 22% in strength and modulus of hot-wet (80 ℃) samples conditioned for 90 days in comparison to room temperature samples. 2 wt% nanophased samples showed increase in strength and modulus (7% and 38% under room temperature, 20% and 29% under hot-wet (80 ℃) ～90 days conditions) over neat samples when similarly conditioned. Scanning electron micrographs (SEM) showed significant decrease in number of cracks in 2 wt% nanophased samples in comparison to neat samples.
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