Radiation effects in natural quartz crystals

Optically clear, as visually observed, natural quartz crystals of Brazilian and Arkansas origins, which exhibit Al–OH^?-centers in their as-received conditions, have been measured for their low temperature ESR spectra to see the presence of Al-hole centers. The ESR spectra revealed the presence of Al-hole centers in their as-received conditions. These centers showed an increase in their strength upon irradiation with a ⁶⁰C0 source. Such observations were exhibited by Al–OH^?-centers as noticed earlier. The crystals were thus noticed to exhibit the presence of Al–OH^?-centers and also Al-hole centers in their as-received conditions. The observations match with the results on cultured quartz where irradiation breaks away the Al-alkali centers into a mixture of Al–OH^?- and Al-hole centers. It is thus concluded that the natural crystals, which exhibit the presence of these centers in their as-received condition, have been irradiated in nature with a low dose.     

Effect of pretreatment conditions on physicochemical parameters of carrot juice

Carrot juice obtained by hydraulic press with wooden set-up was subjected to pretreatments (temperature, time and pH) prior to extraction process. Their effects on the most important quality parameters of carrot juice, such as beta-carotene, reducing sugars, pectin, vitamin C, viscosity, pH and acidity were studied. Response surface methodology was employed, where the experiment was carried out according to a central composite rotatable design. The variables ranges used were 61.50–98.50 °C (temperature), 124.55–595.45 s (time) and 2.31–6.69 (pH – concentration of citric acid). The results showed that beta-carotene extraction was significantly increased (52.9%) with these pretreatments in comparison to control samples. All the derived mathematical models for the responses were found to be fit significantly to predict the data. The responses were optimised by numerical method and were found to be 7190 μg per 100 g beta-carotene, 3.41% reducing sugars, 4.96 mg per 100 g vitamin C, 0.59% pectin, 1.64 × 10³ Ns m⁻² viscosity, 5.26 pH and 4.97% acidity at optimum input variables of 75.26 °C (temperature), 349.89 s (time) and 3.2 (pH). The desirability for all the responses was found to be 83.8%.     

The occurrence of vulnerable seagrass species Halophila beccarii Ascherson, 1871 from restored mangrove of Koduvally Estuary,south‐west coast of India

The ocean turf grass, Halophila beccarii Ascherson, 1871 was recorded for the first time in the intertidal region of the restored mangrove ecosystem of the Koduvally Estuary on the south‐west coast of India. It was found co‐existing in the shallow muddy area of the mangroves, dominated by mangrove trees of Rhizophora mucronata and Sonneratia alba, and macroalgae, Ulva sp., Enteromorpha sp. and Chaetomorpha sp. The meadow is sparsely scattered with shoots near the mangroves, with a mean density of 720 shoots/m². Details regarding the morphology and hydrographic conditions are described. The occurrence of H. beccarii in the Koduvally estuary is an encouraging sign of improved ecosystem health through mangrove restoration. The development of seagrass meadow in the estuary will improve the sediment stability and water quality. A further comprehensive study on the spatiotemporal variation of this species in the estuary is also recommended for conservation and management of this vulnerable seagrass species.     

Velocity measurements in convective boiling flow using radioactive particle tracking technique

The design, performance, and safety analysis of nuclear reactors, in particular boiling water reactors, requires information about the vapor–liquid flow dynamics. Such data are necessary for stand-alone analysis of the thermal hydraulics, as well as to serve as a database for validation of computational fluid dynamics models. Challenges in collecting such data are magnified in the context of flow boiling, which is known to be a complex, multi-scale problem. The present work focuses on investigating the two-phase flow dynamics of convective boiling flows on a test section equipped with different heater rods arrangements. Noninvasive radioactive particle tracking (RPT) has been used for measuring liquid velocity field, mean flow patterns, and turbulent kinetic energy of the liquid phase. A novel tracer particle reconstruction algorithm based on support vector regression has been applied in this study. This is the first application of RPT for measuring liquid velocity fields in convective boiling flows.     

Microwave synthesis of electrode materials for lithium batteries

A novel microwave method is described for the preparation of electrode materials required for lithium batteries. The method is simple, fast and carried out in most cases with the same starting material as in conventional methods. Good crystallinity has been noted and lower temperatures of reaction has been inferred in cases where low temperature products have been identified     

Control of natural ventilation for aerodynamic high-rise buildings

The aim of the paper is to present a framework for the optimal control of natural ventilation. To account for the significant crossflow between zones, the notion of ASHRAE-equivalent airflow is proposed which is used to evaluate the quality of ventilation provided to different zones within a building. A model-based predictive control approach is developed which is used to simulate different ventilation strategies and select the most appropriate strategy. To this end, the rationale behind choosing an objective function that captures the goals of a ventilation system is described, and candidate objective functions are discussed. Finally, an illustrative example with an elliptical cross-section building is discussed in detail. The framework for model-predictive control developed in this paper is applicable beyond natural ventilation and high-rise buildings.     

Comparative Analysis of Different Air Density Equations

In general mass measurements are carried out in air and that’s why air buoyancy correction plays a major role in mass measurements and it is totally dependent on density of air of the laboratory during the measurement. The density of air is calculated from temperature, relative humidity, air pressure, concentration of CO₂ monitored (for CIPM formula only) in the laboratory rather direct determination and for calculation of density of air, CIPM-2007 formula is recognized as most accurate formula. Since CIPM formula is very complicated formula and it is not required for less accurate measurements, different National Metrology Institutes have derived simple equations to calculate air density and those are known as approximation formulas. We had gone through a comparative analysis among different formulas of density of air to evaluate which approximation formula is most accurate compare to CIPM-2007 formula.