Radial Velocity Effects on the Convective Instability Induced by Centrifugal Buoyancy

The effect of radial velocity on the stability of viscous flow between two arbitrarily spaced concentric porous cylinders in the presence of a radial temperature gradient has been examined by numerically solving the resulting differential equation with variable coefficients. The combined influence of suction (or injection) and the temperature gradient has been presented graphically

Fabrication of a Resonant Photoacoustic Cell for Samples Study

Nondestructive treatment of a sample in photoacoustic spectroscopy is helpful in the study of thermal and optical properties of ice and snow. In the present study, a  low-temperature resonant photoacoustic cell, based on Helmholtz resonator model, has been designed and fabricated for the study of samples like ice or snow. Its performance has also been studied using carbon black as a standard sample and various other samples like water, ice, glass, plexi-glass, polycarbonate, etc. Thermal diffusivity of ice, water, and many other transparent materials has been determined by varying chopping frequency and recording corresponding phase changes in the photoacoustic signal. The results obtained are in good agreement with those predicted by Rosencwaig-Gersho (R-G)' theory

Finite time thermodynamic analysis and optimization of solar-dish Stirling heat engine with regenerative losses

The present study investigates the performance of the solar-driven Stirling engine system to maximize the power output and thermal efficiency using the non-linearized heat loss model of the solar dish collector and the irreversible cycle model of the Stirling engine. Finite time thermodynamic analysis has been done for combined system to calculate the finite-rate heat transfer, internal heat losses in the regenerator, conductive thermal bridging losses and finite regeneration process time. The results indicate that exergy efficiency of dish system increases as the effectiveness of regenerator increases but decreases with increase in regenerative time coefficient. It is also found that optimal range of collector temperature and corresponding concentrating ratio are 1000 K~1400 K and 1100~1400, respectively in order to get maximum value of exergy efficiency. It is reported that the exergy efficiency of this dish system can reach the maximum value when operating temperature and concentrating ratio are 1150 K and 1300, respectively

Antioxidants deficiency: a sensitive indicator of cardiometabolic risk in chronic renal failure?

Background: Antioxidant depletion occurring in chronic renal failure patients is an important cause of associated morbidity & mortality, which in turn imposes a great socioeconomic burden of health care. Early diagnosis & targeted management of this preventable deficiency may have a positive impact on the management of co morbidities associated with chronic renal failure.Aims & Objectives: To evaluate the status of antioxidants as an early indicator of cardiometabolic risk in chronic renal failure patients.Settings & Design: This was a randomised case Control study including 10 controls of either sex with normal renal function between age group 20-60 years and 15 patients of chronic renal failure on dialysis between the age group of 16 - 60 years.Methods: 12 hour fasting venous blood samples were collected from all the participants and were assayed for various antioxidants.Statistical analysis: Results were analyzed by unpaired t test, p value was determined & Correlation coefficient was calculated amongst various parameters.Results: In the present study, significantly low levels of vitamin C ( Cases: 0.367 ± 0.13 mg/dl controls: 1.324 ± 0.61 mg/dl; p < 0.01) & vitamin E  (cases: 0.235 ± 0.102 mg/dl, controls (0.854 ± 0.28 mg/dl; p < 0.01) were observed in chronic renal failure patients as compared to controls.Conclusion: Diminished levels of Vitamin C & E in our study may be an indicator of increased oxidative stress which can be a responsible factor for increased incidence of cardiovascular complications. Supplementing these patients with recommended dosage of these vitamins may provide an essential tool to reduce the burden of suffering

Genetic divergence and its implication in breeding of desired plant type in coriander -Coriandrum sativum L.-

Seventy germplasm lines of coriander (Coriandrum sativum L.) of diverse eco-geographical origin were undertaken in present investigation to determine the genetic divergence following multivariate and canonical analysis for seed yield and its 9 component traits. The 70 genotypes were grouped into 9 clusters depending upon the genetic architecture of genotypes and characters uniformity and confirmed by canonical analysis. Seventy percent of total genotypes (49/70) were grouped in 4 clusters (V, VI, VIII and IX), while apparent diversity was noticed for 30 percent genotypes (21/70) that diverged into 5 clusters (I, II, III, FV, and VII). The maximum inter cluster distance was between I and IV (96.20) followed by III and IV (91.13) and I and VII (87.15). The cluster VI was very unique having genotypes of high mean values for most of the component traits. The cluster VII had highest seeds/umbel (35.3 ± 2.24), and leaves/plant (12.93 ± 0.55), earliest flowering (65.05 ± 1.30) and moderately high mean values for other characters. Considering high mean and inter cluster distance breeding plan has been discussed to select desirable plant types

Clean coal technology to improve environmental qualtiy and energy efficiency

Coal is the world’s most abundant and widely distributed fossil fuel source. It is a major source of commercial energy in the present scenario. Coal currently supplies over one third of the world’s electricity and 23% of global primary energy needs. Conventional power generation system, though one of the cheapest means of production of electricity in the world, have energy efficiency only 30-35%. However, it has enormous environmental impact which includes emission of large amount of gases like CO2, SO2, NOx, and Hg, particulate matter which primarily includes fly ash. This is responsible for global warming and air and water pollution. To reduce this environmental impact due to emissions from thermal power plant and to meet the quality requirements of the coal consumers, it is imperative to adopt clean coal technologies. “Clean coal” is a term used in the promotion of the use of coal as an energy source by emphasizing methods being developed to reduce its environmental impact. This paper addresses advanced power generation systems like integrated gasification combined cycle (IGCC) system and underground coal gasification (UCG) which claim to have energy efficiency in the rage of 45-50%. Carbon capture and storage (CCS) technology for capturing emitted CO2 and storing it in geological formation appears to be one of the efficient means to reduce CO2 in the atmosphere. This technology has also been enumerated in this paper. An account for global and Indian initiatives for clean coal technology is given. Clean coal mining operation along with coal preparation technology practiced in India is also discussed in brief

Two Graviton Production at e+e−e^+e^- and Hadron Hadron Colliders in the Randall-Sundrum Model

We compute the pair production cross section of two Kaluza Klein modes in the Randall-Sundrum model at $e^+e^-$ and hadron hadron colliders. These processes are interesting because they get dominant contribution from the graviton interaction at next to leading order. Hence they provide a nontrivial test of the low scale gravity models. All the Feynman rules at next to leading order are also presented. These rules may be useful for many phenomenological applications including the computation of higher order loop corrections.Comment: 24 pages, 11 figures, some typos correcte