Leaching of residues of certain pesticides from black tea to brew

Tea is the most commonly consumed beverage in the world. It is prepared after infusing processed black tea in hot water. During the process of brewing, along with flavour and aroma, the residues of plant protection chemicals may also be transferred into the tea brew or infusion. The leaching of certain pesticides, such as ethion, endosulfan, dicofol, chlorpyrifos, deltamethrin, hexaconazole, fenpropathrin, propargite, quinalphos and lambdacyhalothrin from powdered black tea into the brew was studied. The rate of transfer of the pesticide residue from black tea to the hot brew was largely influenced by physicochemical parameters, such as water solubility and octanol-water partition coefficient. Tea brews prepared from untreated black tea samples were fortified with standard solutions of the respective pesticides, extracted and analysed using GC and HPLC by following standardised methods. Results revealed that the rate of leaching of residues of these pesticides into the tea brew was low due to their low solubilities in aqueous medium and high octanol-water partitioning coefficients.     

Simulation of double-stage double-effect metal hydride heat pump

This paper presents the operational characteristics of a double-stage double-effect metal hydride heat pump (DSDE-MHHP) working with LaNi_4.1Al_0.52Mn_0.38/LmNi_4.91Sn_0.15/Ti_0.99Zr_0.01V_0.43Fe_0.09Cr_0.05Mn_1.5 as high/medium/low temperature alloys. The performances of the DSDE-MHHP are predicted by solving the transient, two-dimensional, conjugate heat and mass transfer characteristics between the paired metal hydride reactors of cylindrical configuration using the finite volume method (FVM). The designed operating temperatures chosen for the present analysis are 568, 361, 296, and 289 K as heat driven (T_D), heat rejection (T_H), heat sink (T_M) and refrigeration (T_C) temperatures, respectively. The variations in hydrogen concentrations, hydride equilibrium pressures, and temperatures within the hydride beds, and the heat exchange between the hydride beds with the heat transfer fluids are presented for a complete cycle. The operating cycle of a DSDE-MHHP is explained on dynamic pressure–concentration–temperature (PCT) plot. The variation of temperatures in the reactors during hydriding and dehydriding processes is compared with experimental data and a good agreement was observed between them. For given operating temperatures of 568/361/296/289 K, the average coefficient of performance (COP) and the specific cooling power (SCP) of the system are found to be 0.471 and 28.4 W/kg of total hydride mass, respectively.     

Enzymatic saccharification and fermentation of paper and pulp industry effluent for biohydrogen production

Paper and pulp industry effluent was enzymatically hydrolysed using crude cellulase enzyme (0.8–2.2FPU/ml) obtained from Trichoderma reesei and from the hydrolysate biohydrogen was produced using Enterobacter aerogenes. The influence of temperature and incubation time on enzyme production was studied. The optimum temperature for the growth of T. reesei was found to be around 29 °C. The enzyme activity of 2.5 FPU/ml was found to produce about 22 g/l of total sugars consisting mainly of glucose, xylose and arabinose. Relevant kinetic parameters with respect to sugars production were estimated using two fraction model. The enzymatic hydrolysate was used for the biohydrogen production using E. aerogenes. The growth data obtained for E. aerogenes were fitted well with Monod and Logistic equations. The maximum hydrogen yield of 2.03 mol H₂/mol sugar and specific hydrogen production rate of 225 mmol of H₂/g cell/h were obtained with an initial concentration of 22 g/l of total sugars. The colour and COD of effluent was also decreased significantly during the production of hydrogen. The results showed that the paper and pulp industry effluent can be used as a substrate for biohydrogen production.     

Effects of salt and ammonium hydroxide on the quality of ground buffalo meat

The objective of this study was to evaluate the effects of ammonium hydroxide (AH) and sodium chloride on the quality of ground buffalo meat patties. Ground buffalo meat was treated with distilled water (control), 0.5% v/w AH, 1.0% v/w AH, 2.0% v/w AH and 1.0% w/w sodium chloride was added for all the samples. Treatment with AH increased (P<0.05) the pH and water holding capacity (WHC) of ground buffalo meat patties during storage relative to their controls. Hunterlab a* (redness) and chroma values increased (P<0.05) and hue decreased (P<0.05) in all AH treated samples in comparison to controls during storage. Ammonium hydroxide significantly (P<0.05) inhibited metmyoglobin formation compared to control after 3rd day of storage. There was a significant (P<0.05) reduction in thiobarbituric acid reactive substances (TBARS) values in all AH treated samples compared to control throughout storage. These results indicate the potential antioxidant and myoglobin redox stabilizing effect of AH in ground buffalo meat patties.     

Thermal modeling and performance analysis of industrial-scale metal hydride based hydrogen storage container

In this paper, a performance analysis of a metal hydride based hydrogen storage container with embedded cooling tubes during absorption of hydrogen is presented. A 2-D mathematical model in cylindrical coordinates is developed using the commercial software COMSOL Multiphysics 4.2. Numerical results obtained are found in good agreement with experimental data available in the literature. Different container geometries, depending upon the number and arrangement of cooling tubes inside the hydride bed, are considered to obtain an optimum geometry. For this optimum geometry, the effects of various operating parameters viz. supply pressure, cooling fluid temperature and overall heat transfer coefficient on the hydriding characteristics of MmNi_4.6Al_0.4 are presented. Industrial-scale hydrogen storage container with the capacity of about 150 kg of alloy mass is also modeled. In summary, this paper demonstrates the modeling and the selection of optimum geometry of a metal hydride based hydrogen storage container (MHHSC) based on minimum absorption time and easy manufacturing aspects.     

Analysis of piezoresistive behavior of polyaniline-coated nylon Lycra fabrics for elbow angle measurement

In this article, a textile-based strain sensor has been developed by in situ polymerization of aniline on nylon Lycra fabric. The tensile and repeatability characteristics of the nylon Lycra fabric were studied in Zwick/Roell Z010 tester to analyze the suitability of the fabric for sensor development. After polyaniline coating, the control and coated fabrics have been characterized by means of scanning electron microscopy and energy dispersive X-ray. The change in electrical resistance for the applied strain was studied to analyze the strain sensing behavior of the polyaniline-coated nylon Lycra fabric. From tensile and repeatability study, it was observed that the conditioning cycles are necessary for the nylon Lycra fabric before taking actual measurements in order to improve the stability of the sensor response. The developed fabric had the electrical resistance of 3.5 KΩ/square. The electrical resistance of the developed PANI-coated fabric decreases as the sample is strained and increases again as the strain is relaxed. The measurement of the conductivity change with strain shows that the developed fabric exhibits high strain sensitivity. When used in conjunction with a commercial goniometer, the polyaniline-coated nylon Lycra fabric responded well to the magnitude of bending deformations, demonstrating potential for remote the strain sensing applications.     

Computational study on metal hydride based three-stage hydrogen compressor

A mathematical model for predicting the performances of a three-stage metal hydride based hydrogen compressor (MHHC) is presented. The performance of the MHHC is predicted by solving the unsteady heat and mass transfer characteristics of the coupled metal hydride beds of cylindrical configuration. The governing equations for energy, momentum and mass conservations, and reaction kinetic equations are solved simultaneously using the finite volume method. Metal hydrides chosen for a three-stage MHHC are LaNi₅, MmNi_4.6Al_0.4 and Ti_0.99Zr_0.01V_0.43Fe_0.99Cr_0.05Mn_1.5. Numerical results obtained for a single-stage MHHC using MmNi_4.6Al_0.4 are in good agreement with the experimental data reported in the literature. Using three-stage compression, a maximum pressure ratio of 28 is achieved for the supply conditions of 20 °C absorption temperature and 2.5 bar supply pressure. A maximum delivery pressure of 100 bar is obtained for the operating conditions of 20 °C absorption temperature and 120 °C desorption temperature.     

Long‐term impact of nitrogen and potassium fertilizers on yield,soil nutrients and biochemical parameters of tea

A field experiment was conducted with tea cultivar UPASI‐9 over a period of 9 years to evaluate the long‐term effects of nitrogen (N) and potassium (K) fertilizers on yield, biochemical parameters, soil and leaf nutrient status. The yield increase was as high as 66% over the control for N application of 450 kg ha^?1 year^?1. Polyphenol and amino acid contents increased with increase in K application rate. Positive and significant correlation was found between nitrate reductase activity and the amino acid content of the tea shoots. While ammoniacal nitrogen in the soil was not affected by the application of fertilizer, ammonium acetate extractable K increased. The failure to apply fertilizer resulted in depletion of the organic matter status of the soil. Although increased rate of nitrogen application increased the overall yield of made tea (kg ha^?1 year^?1), the specific yield (kg kg^?1 N) declined. The soil tended to become acidic from frequent application of high doses of nitrogenous fertilizer. The leaf NK status was significantly influenced by the various treatments. Copyright © 2004 Society of Chemical Industry     

Learning automata–based multilevel medium access control in cyber physical system–based smart wireless networks

The performance of cyber physical system–based smart wireless networks depends on effective channel access by reducing the blocking, the dropping probability, and collisions. The aim of this proposed algorithm is to reduce the collisions in cyber physical system–based smart wireless networks. In this paper, multilevel medium access control in cyber physical system–based smart wireless networks is proposed. The optimal number of levels of gateways is determined using the concept of learning automata. Priority and time limit are assigned to every packet that is being transmitted. The proposed algorithm is evaluated and compared with two‐level medium access control in cyber physical system–based smart wireless networks, which is referred as priority with counter modified backoff (PCMB). The parameters used for evaluating the performance are throughput, delay, % of collisions, and number of packets dropped. The results project that the proposed algorithm accomplishes improved performance than PCMB.