Extraction of assam coal through reductive acylation

Assam coal was reductively acylated by using zinc dust, acetic acid and phenol. This reaction resulted in enhanced extractability of coal in quinoline. The residue extracted after the first step was further reductively acylated which rendered it further extractable in quinoline. Three successive steps could solubilize the coal to the extent of 58 per cent on ash balance basis.     

Laser-Tuned Surface Wettability Modification and Incorporation of Aluminum Nitride (AlN) Ceramics in Thermal Management Devices

Aluminum nitride (AlN), a versatile ceramic with high thermal conductivity, high electrical resistivity, and a coefficient of thermal expansion compatible with silicon, is well-suited for direct-to-chip cooling applications of electronics, implementation in wide bandgap semiconductors, and for high-temperature heat exchangers. Despite multiple advantages, AlN's implementation in liquid-cooling applications is often hindered by surface-degrading effects of working-fluid-induced hydrolysis. Herein, a scalable -but highly tunable- wettability engineering approach is introduced, that allows effective implementation of bulk AlN substrates in enhanced two-phase cooling of electronics. The approach prevents hydrolysis of AlN by aqueous media and establishes control over surface roughness, all the while maintaining bulk integrity and material properties of the underlying substrate. Demonstration of the new approach is presented in spontaneous, pumpless, surface liquid transport, a necessity if such ceramics are to play an integral role as components of sealed, phase-change, wickless thermal-management devices (e.g., vapor chambers or heat pipes) that require rapid working-fluid transport in their multi-phase interior. The novelty of this work lies in establishing a scalable methodology for utilizing and further enhancing the properties of this non-oxide ceramic material for phase-change heat-transfer hermetic devices, thereby paving the way toward the implementation of this intriguing material in next-generation heat spreaders.     

tert-Butyl Nitrite Promoted Visible-Light-Induced Steric-Hindrance-Regulated Concurrent Cross-Coupling and Regioselective Nitration of 3-Alkylidene-2-oxindoles

A tert-butyl nitrite (TBN) promoted visible-light-induced one-pot C−N cross coupling reaction of 3-alkylidene-2-oxindoles with benzene-1,2-diamine was explored. Simultaneously, the indoline motif of 3-alkylidene-2-oxindoles as well as 3-ylidene oxindoles are regioselectively nitrated at the C-6 position by in-situ formed NO₂ radical. (E)-3-(2-(aryl)-2-oxoethylidene)oxindole and (E)-3-ylidene oxindole produce distinct nitrated diastereomeric coupling products, a phenomenon influenced by the steric bulk of the functional group. The experimental findings suggest the potential involvement of a radical pathway in this reaction.     

Phase-only adaptive Processing based on a direct data domain least squares approach using the conjugate gradient method

Generally, adaptive antenna arrays operate by changing the complex adaptive weights consisting of both magnitudes and phases applied at each of the antenna elements. However, it is easier to require the adaptive weights have only phase variation with a fixed magnitude at each of the antenna elements. Hence, This work addresses the phase only adaptive systems whose weights have a fixed magnitude through a new phase only adaptive method based on a direct data domain least squares approach (D/sup 3/LS), which utilize only a single snapshot of the data for adaptive processing.     

A simple algorithm for detection of significant vertices for polygonal approximation of chain-coded curves

A simple but efficient method is proposed for detection of significant points of chain-coded curves. The polygonal approximation is achieved by joining successive significant vertices. The algorithm is based on manipulation with chain codes only.     

Synthesis and characterization of gelatin based polyester urethane scaffold

For tissue engineering purpose two gelatin based polyester urethane scaffolds of different compositions were prepared from lactic acid, polyethylene glycol 400 (PEG 400) and characterized by FTIR, XRD for their mechanical and morphological properties using SEM and optical microscopic analyses. Degradation and swelling studies of gelatin based polyester urethane scaffolds in phosphate buffer saline (PBS) were performed. Human keratinocyte cells were cultured within these scaffolds, which showed good cell adherence and proliferation.     

Chronic arsenic toxicity in west Bengal--the worst calamity in the world

Since 1983 large number of people are being encountered with arsenic toxicity due to drinking of arsenic contaminated water (0.05-3.2 mg/l) in 6 districts of West Bengal. Clinical and various laboratory investigations were carried out on 156 patients to ascertain the nature and degree of morbidity and mortality that occurred due to chronic arsenic toxicity. All the patients studied had typical rain drop like skin pigmentation (being inclusion criteria) while thickening of palm and sole were found in 65.5% patients. Other features included weakness (70%), gastro-intestinal symptoms (58.6%), involvement of respiratory system (57.08%) and nervous system (50.6%). Lung function tests showed restrictive lung disease in 53% (9/17) and combined obstructive and restrictive lung disease in 41% (7/17) of patients. Abnormal electromyography was found in 34.8% (10/29) and altered nerve conduction velocity in 34.8% (10/29) of cases. Enlargement of liver was found in 120 cases (76.9%) while splenomegaly in 31.4% cases. Liver function test showed elevated globulin level in 15.8% and alkaline phosphatase in 51.3%, alanine amino transferase (ALT) in 11.8% and aspartate amino transferase (AST) in 27.6% of cases. Evidence of portal hypertension was found in 33.3% patients. Liver biopsy reports of 45 patients showed non-cirrhotic portal fibrosis in 41, cirrhosis in 2 and normal histology in 2 cases. There was no correlation between the quantity of arsenic taken through water and the level of arsenic in hair, nail, liver tissues and the degree of fibrosis. There were 5 deaths of which one had skin cancer. The various non-cancer manifestations which were observed in these patients were much severe than those reported in similar cases in other parts of the world.     

Performance study of a partial gasification pressurized combustion topping gas cycle and split rankine combined cycle: Part I— Energy analysis

The aim of this paper is to study the thermodynamic performance of a new combination of a partial gasification pressurized combustion topping gas cycle and a split Rankine bottoming steam cycle as a means of advanced clean coal power generation. Energy analysis of the conceptualized power cycle is presented in this part of the paper. The effects of design and operating parameters of both the gas and the steam cycles on the performance of the power cycle are discussed. Copyright © 2003 John Wiley & Sons, Ltd.     

Transcritical CO2 Heat Pump Dryer: Part 1. Mathematical Model and Simulation

In this study, a mathematical model and simulation code has been developed to investigate the performance of a transcritical CO₂ heat pump dryer. The model takes into account detailed heat and mass transfer and pressure drop phenomena occurring in each component of the system. To take care of the variable heat transfer properties, the heat exchanger components were divided into several infinitesimal segments to examine the state, heat and mass balance and pressure drop for both refrigerant and air, and hence accurate results are expected. In Part 2 of the article, the model developed has been validated with experimental data and then the model was used to investigate effects of important operating parameters on the performance.