A new synthesis route of ammonia production through hydrolysis of metal – Nitrides

Recently ammonia has emerged as a potential hydrogen storage material because it contains 17.8 wt% hydrogen. Here, we propose a new synthesis route of ammonia production using hydrolysis of nitrides, which is based on the conversion technique using thermal energy, solar heat or exhaust heat to form NH₃ directly. Lithium metal has been tested as a starting material for the above purpose. We present the detailed results on room temperature nitridation of lithium metal, it is found that the nitridation properties are strongly affected by the surface state of lithium metal. The ammonia synthesis via hydrolysis of lithium nitride succeeds and it is strongly dependent on the reaction rate and temperature.     

Analysis of Fluopicolide and Propamocarb Residues on Tomato and Soil Using QuEChERS Sample Preparation Method in Combination with GLC and GCMS

Persistence of fluopicolide and propamocarb in tomato was studied following three applications of a combination formulation of Infinito 68.75 SC (fluopicolide 6.25 %?+?propamocarb 62.5 %) at 1500 and 3000 mL ha^?1 by 7 days interval, starting the spray at fruit development stage. QuEChERS method included extraction of sample with ethyl acetate and cleanup of dispersive solid-phase extraction was used for the determination of fluopicolide and propamocarb residues on tomato and soil. Residues of fluopicolide and propamocarb in tomato were estimated by gas–liquid chromatography and gas chromatograph–mass spectrometry, respectively. Half-lives for fluopicolide were found to be 2.58 and 2.31 days, whereas for propamocarb these values were observed to be 1.49 and 2.08 days at single and double the application rates, respectively. Residues of fluopicolide dissipated below its limit of quantification (LOQ) of 0.01 mg kg^?1 after 7 and 10 days at single and double the application dosage, respectively. Similarly, residues of propamocarb took 5 and 7 days to reach LOQ of 0.10 mg kg^?1, at single and double dosages, respectively. Soil samples collected after 15 days of the last application did not show the presence of fluopicolide and propamocarb at their detection limit of 0.01 and 0.10 mg kg^?1, respectively. The initial deposit of residues of propamocarb and fluopicolide for both the dosages were below the prescribed codex maximum residue limit values of 2 and 1 mg kg^?1, respectively. Therefore, a 1-day waiting period was suggested to reduce human health risks before consumption of tomato fruits.     

Studies on the solubility of hydrogen in molten Pb83Li17 eutectic alloy

Lead–lithium eutectic (Pb₈₇Li₁₇) alloy is a candidate material to be used as a secondary tritium breeder, neutron multiplier and heat transfer agent in the fusion reactor. The tritium thus produced in the alloy may be soluble or appear as a new phase of lithium-tritides and/or lead-tritides, which eventually affect the performance of Pb₈₃Li₁₇ eutectic. Therefore, solubility of tritium in the alloy at the operating conditions of the fusion reactor is a subject matter of investigation. Tritium being the isotope of hydrogen behaves more or less similar to the hydrogen. In the present investigation the solubility of hydrogen in the Pb₈₃Li₁₇ has been investigated as a function of temperature and pressure. It was found that, hydrogen solubility in the Pb₈₇Li₁₇ alloy is almost constant above 350 °C. Hydrogen solubility increases with increase of temperature up to 400 °C. Hydrogen solubility is 120 ppm at 400 °C and 800 Torr hydrogen pressure. The solubility decreases on further rise in temperature from 400 °C. However, at all the temperatures hydrogen solubility increased with increase of partial pressure of hydrogen.     

A review on synthesis and characterization of commercially available natural fibers: Part II

Increasing environmental concerns, along with the potential declination of the crude worldwide reserves, have made the human beings to utilize more regenerable resources to substitute for the design and development of more new products. This has made us to use the synthetic and natural fibers to develop innovative products. However, more eco-friendly properties of natural fibers have made them to be preferable over the synthetic fibers. To make efficient use of these fibers, it is essential to know the behavioral characteristics of these fibers. So, in this review II paper, an effort has been made to discuss the various characterization analysis studies, like Fourier transform-infrared spectra spectral analysis, X-ray and thermogravimetric methods carried out by various researchers.     

Overall thermal energy and exergy analysis of hybrid photovoltaic thermal array

In this paper, overall thermal energy and exergy analysis has been carried out for different configurations of hybrid photovoltaic thermal (PVT) array. The hybrid PVT array (10.08 m × 2.16 m) is a series and parallel combinations of 36 numbers of PV modules. A one-dimensional transient model for hybrid PVT array has been developed using basic heat transfer equations. On the basis of this transient model, an attempt has been made to select an appropriate hybrid PVT array for different climatic conditions (Bangalore, Jodhpur, New Delhi, and Srinagar) of India. On the basis of high grade energy (i.e. overall exergy gain), case-III has been selected as the most appropriate configuration because overall exergy for case-III is 12.9% higher than case-II. The overall thermal energy and exergy gain for Bangalore is 4.54 × 10⁴ kW h and 2.07 × 10⁴ kW h respectively which is highest in comparison to the other cities.     

Meteorologically efficient commissioning of salt gradient solar pond

Salt gradient solar pond has thermal performance parameters as rate of warm-up, highest achievable temperature, and cumulative heat collection. All these are strongly influenced by the meteorology. Consequently, specific to the meteorology of a geographic location, there is a best starting day for the as pond defined by Singh et al. [1]. The present work has done rigorous analysis of influence of meteorology on pond??s thermal performance. It is found that the starting day has strong influence in initial stage of pond warm-up; however the effect diminishes in long-term. Finally pond started on any day of the year acquires same highest temperature. It is also found that in order to retrieve maximum heat, waiting for the best starting day to commission a pond is not judicious, rather it is always more beneficial commission the pond at the earliest possible day. This finding is of practical significance while planning to put a pond in operation.     

A study of large-cardamom curing chambers in Sikkim

India is the largest producer of large cardamom in the world with an annual production of 4000 tons, followed by Nepal (2500 tons/year) and Bhutan (1000 tons/year). More than 85% of the production within India is from Sikkim. Firewood is used extensively for curing cardamom in small, traditional curing chambers called “bhattis”. The traditional curing process is not only inefficient, resulting in an estimated fuelwood wastage of 20 000 tons/year, but also yields a poor quality product. An attempt is made in the present work to analyze the thermal performance of the traditional “bhattis” through field survey and operational data collection. Based on the experimental observations and analysis, options for improvement such as use of a gasifier are suggested.     

Nickel-palladium nanoparticle catalyzed hydrogen generation from hydrous hydrazine for chemical hydrogen storage

In this study, we report Ni-Pd bimetallic nanoparticle catalysts (nanocatalyst) (Ni_1-xPd_x) synthesized by alloying Ni and Pd with varying Pd contents, which exhibit appreciably high H₂ selectivity (>80% at x = 0.40) from the decomposition of hydrous hydrazine at mild reaction condition with Ni_0.60Pd_0.40 nanocatalyst, whereas the corresponding monometallic counterparts are either inactive (Pd nanoparticles) or poorly active (Ni nanoparticles exhibit 33% H₂ selectivity). In addition to powder X-ray diffraction (XRD), X-ray photoelectron spectra (XPS) analysis and electron microscopy (TEM/SEM), the structural and electronic characteristics of Ni-Pd nanocatalysts were investigated and established using extended X-ray absorption fine structure (EXAFS) analysis. Unlike the high activity of Ni-Pd nanocatalysts, Pd-M (M = Fe, Co and Cu) bimetallic nanocatalysts exhibit poor catalytic activity. These results imply that alloy composition of Ni-Pd nanocatalysts is critical, where the co-existence of both the metals on the catalyst active surface and the formation of inter-metallic Ni-Pd bond results in high catalytic performance for the decomposition of hydrous hydrazine to hydrogen.     

Experimental validation of glazed hybrid micro-channel solar cell thermal tile

In this communication, an attempt has been made to evaluate the theoretical performance of a glazed hybrid micro-channel solar cell thermal (MCSCT) tile. Experiment has been performed in indoor condition and it has been observed that there is good agreement between theoretical and experimental values with correlation coefficient and root mean square percentage deviation in range of 0.995–0.998 and 3.21–4.50 respectively. Effect of design parameters on different combination (series and parallel) of glazed hybrid MCSCT tile for Srinagar climatic condition, India has also been evaluated. The theoretical results of glazed hybrid micro-channel photovoltaic thermal (MCPVT) module for 75 W_p have been compared with the result of single channel photovoltaic thermal (SCPVT) module. The average value of electrical and thermal efficiency of glazed hybrid MCPVT module are 14.7% and 10.8% respectively which is significantly higher than SCPVT module. The overall annual exergy efficiency based on second law of thermodynamics has also been evaluated at different mass flow rate for glazed hybrid MCPVT module for Srinagar climatic condition. It has been observed that maximum overall exergy efficiency is 20.28% at 0.000108 kg/s mass flow rate.     

Experimental determination of permeability in the presence of hydrates and its effect on the dissociation characteristics of gas hydrates in porous media

Although there are many uncertainties in hydrate dissociation process in porous media, numerical simulation gives useful information in evaluating economically feasible gas recovery processes from gas hydrate reservoirs. Furthermore, there are several unknown parameters involved in the numerical model and determination of accurate values of these parameters is essential for reliable production forecasts. One of these parameters is the variation of permeability of the porous media in the presence of hydrates. In this study the permeability to gas was experimentally determined at varying hydrate saturations in a porous medium made of packed glass beads.By comparing the experimentally determined permeability with those calculated using the empirical permeability correlations it was found that for initial water saturations less than 35%, hydrate tends to form on the grain surfaces. However, for initial water saturations greater than 35%, the experimental results indicate a pore filling tendency of hydrate formation. The experimental permeability values were also correlated with the Masuda et al.'s (1997) permeability model and a value of 3.0 was obtained for the permeability reduction exponent. To evaluate the impact of permeability reduction exponent on the dissociation process, a one-dimensional numerical model was developed for dissociation of gas hydrates in porous media by depressurization. The numerical model includes the three mechanisms i.e. kinetics of hydrate decomposition, heat transfer and fluid flow; that might be associated with the dissociation of hydrates in porous medium. The effect of permeability reduction exponent on the dissociation characteristics of hydrate was analyzed using this simulator.