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In this study, ultrafiltration membranes are prepared in outside skin tubular configurations using polysulfone polymer with and without mesoporous silica and aluminium oxide powder (~3.8–4.0 nm pore size) independently. Prepared membranes are characterized in terms of pure water flux, separation of single uncharged solutes like polyethylene oxide (PEO), water contact angle and average surface roughness. After filtration of turbid seawater (50–60 NTU) to remove the turbidity, pure water flux recoveries of all the membranes were evaluated after cleaning by backwashing with deionized (DI) water. It was found that flux recovery is better in nanocomposite membranes than in purely polysulfone coated membranes. The extent of turbidity removal was studied as a function of turbidity load and temperature of seawater. Incorporation of the porous nanoparticles in pure polymer matrixes not only enhanced the water flux without sacrificing selectivity but it also increased the fouling resistance of the UF membranes. After 2 month operation, no performance deterioration was observed for all the tubular membranes.

In this study, both reverse osmosis (RO) and forward osmosis (FO) experiments are conducted to concentrate simulated inactive ammonium diuranate (ADU) filtered effluent solution (by mixing uranyl nitrate and ammonium nitrate) using indigenously developed cellulose acetate blend (CAB) and thin-film composite polyamide (TFCP) membranes. Both the membranes are prepared and characterized in terms of pure water permeability and solute rejection for 2000 ppm NaCl feed, water contact angle and surface average roughness. Subsequently, testing of volume reduction and concentration of simulated ADU effluent solution are carried out using custom made RO and FO testing systems. It is found that in RO process, the performance in terms of volume reduction factor and concentration factor with respect to uranium for both CAB and TFCP membranes are comparable but the CAB membranes show better performance than the TFCP membranes in FO modes. The concentration of ammonium nitrate is less in RO concentrate than in the FO concentrates. Similar experiments with the feed solution having different concentration of uranium (1–20 ppm) with same concentration of ammonium nitrate show that in FO, almost no leaching of uranium is found to the draw solution side but in RO, some of the uranium starts passing to the permeate side, particularly at lower concentration of uranium in the feed.

AbstractIn this study, both reverse osmosis (RO) and forward osmosis (FO) experiments are conducted to concentrate simulated inactive ammonium diuranate (ADU) filtered effluent solution (by mixing uranyl nitrate and ammonium nitrate) using indigenously developed cellulose acetate blend (CAB) and thin-film composite polyamide (TFCP) membranes. Both the membranes are prepared and characterized in terms of pure water permeability and solute rejection for 2000 ppm NaCl feed, water contact angle and surface average roughness. Subsequently, testing of volume reduction and concentration of simulated ADU effluent solution are carried out using custom made RO and FO testing systems. It is found that in RO process, the performance in terms of volume reduction factor and concentration factor with respect to uranium for both CAB and TFCP membranes are comparable but the CAB membranes show better performance than the TFCP membranes in FO modes. The concentration of ammonium nitrate is less in RO concentrate than in the FO concentrates. Similar experiments with the feed solution having different concentration of uranium (1–20 ppm) with same concentration of ammonium nitrate show that in FO, almost no leaching of uranium is found to the draw solution side but in RO, some of the uranium starts passing to the permeate side, particularly at lower concentration of uranium in the feed.

In this study, ultrafiltration (UF) membranes were prepared in outside skin tubular configuration using polysulfone and sulfonated polysulfone polymers in order to study the effect of chemical nature of membrane surface on separation performance as well as surface fouling. Separation of polysaccharide and protein with its fouling tendency, removal efficiency of turbidity from seawater with flux recovery after fouling were evaluated. Tubular configuration was chosen, as the membrane surface is most exposed for cleaning after fouling than any other configurations. Bovine serum albumin (BSA) and sodium salt of alginic acid were used as model protein and polysaccharide, respectively, to probe the rejection behavior of these tubular membranes. Sulfonated polymeric membranes were compared with pure polymer membranes for resistance to fouling by the model protein and polysaccharide solutions. Pure water fl ux recovery on water flushing for polysaccharide fouled membrane was comparatively more (6–8%) than protein fouled membrane, particularly in case of polysulfone membrane. In general, the pure water flux recovery after fouling, i.e., reversibility of fouling was more (up to 10%) for sulfonated polysulfone membranes than that of pure polysulfone membranes. Finally, these membranes in tubular configurations were used for removal of turbidity from seawater as periodic washing by flow reversal recovers flux after fouling.

Nanotechnology is a potential augmentation to the existing water purification technologies. Four different types of functional nanomaterials, like carbon nanotubes, metal/metal oxide nanoparticles, dendrimers and zeolites, are currently under evaluation for water purification application. Nanomaterials offer excellent opportunities because of high surface area (surface/ volume ratio), but the challenge is to build up an integrated scalable system. Membranes, because of being energy-economic and having the ability to get associated to different processes as a pretreatment or post-treatment stage, fi nd tremendous applications in the field of water purification. Nanostructured materials serve as a wonderful tool towards development of high flux, high selective membranes. Here attempts are made to develop biofouling resistant membrane. Nanoparticles of silver, copper and silver–copper mixture were impregnated on to the polysulfone host matrix and the biofouling resistance behavior of each membrane surface was examined. The performance of the membranes was evaluated in terms of pure water permeability and solute rejection studies. The membranes were characterized using scanning electron microscopy, energy dispersive X-ray, water contact angle and atomic force microscopy studies. The authors conclude that the silver impregnated membranes possess the best biofouling resistant behavior. The present paper discusses the potential of nanoparticles for water purifi cation and explains briefly the R&D work carried out in the research centre towards development of a biofouling resistant nanocomposite membrane.

In this study, ultrafiltration (UF) membranes were prepared in outside skin tubular configuration using polysulfone and sulfonated polysulfone polymers in order to study the effect of chemical nature of membrane surface on separation performance as well as surface fouling. Separation of polysaccharide and protein with its fouling tendency, removal efficiency of turbidity from seawater with flux recovery after fouling were evaluated. Tubular configuration was chosen, as the membrane surface is most exposed for cleaning after fouling than any other configurations. Bovine serum albumin (BSA) and sodium salt of alginic acid were used as model protein and polysaccharide, respectively, to probe the rejection behavior of these tubular membranes. Sulfonated polymeric membranes were compared with pure polymer membranes for resistance to fouling by the model protein and polysaccharide solutions. Pure water fl ux recovery on water flushing for polysaccharide fouled membrane was comparatively more (6–8%) than protein fouled membrane, particularly in case of polysulfone membrane. In general, the pure water flux recovery after fouling, i.e., reversibility of fouling was more (up to 10%) for sulfonated polysulfone membranes than that of pure polysulfone membranes. Finally, these membranes in tubular configurations were used for removal of turbidity from seawater as periodic washing by flow reversal recovers flux after fouling.

Nanotechnology is a potential augmentation to the existing water purification technologies. Four different types of functional nanomaterials, like carbon nanotubes, metal/metal oxide nanoparticles, dendrimers and zeolites, are currently under evaluation for water purification application. Nanomaterials offer excellent opportunities because of high surface area (surface/ volume ratio), but the challenge is to build up an integrated scalable system. Membranes, because of being energy-economic and having the ability to get associated to different processes as a pretreatment or post-treatment stage, fi nd tremendous applications in the field of water purification. Nanostructured materials serve as a wonderful tool towards development of high flux, high selective membranes. Here attempts are made to develop biofouling resistant membrane. Nanoparticles of silver, copper and silver–copper mixture were impregnated on to the polysulfone host matrix and the biofouling resistance behavior of each membrane surface was examined. The performance of the membranes was evaluated in terms of pure water permeability and solute rejection studies. The membranes were characterized using scanning electron microscopy, energy dispersive X-ray, water contact angle and atomic force microscopy studies. The authors conclude that the silver impregnated membranes possess the best biofouling resistant behavior. The present paper discusses the potential of nanoparticles for water purifi cation and explains briefly the R&D work carried out in the research centre towards development of a biofouling resistant nanocomposite membrane.

AbstractAnalysis of exfoliated buccal cell micronuclei (MN) is a sensitive method of monitoring genetic damage in the human population. In the present study 50 patients with precancerous or malignant oral epithelial lesions from the Departments of Facio-maxillary and ENT Surgery of RKMSP Hospital, Kolkata were compared with 50 age and sex matched healthy controls without any oral lesions.The MN frequency was increased in preoperative cancer cases and decreased in postoperative cases, while in pre cancerous cases it was higher than in the controls.

In order to analyze high temperature deformation behavior of NiAl alloys, deformation maps were constructed for stoichiometric NiAl materials with grain sizes of 4 and 200 µm. Relevant constitute equations and calculation method will be described in this paper. These maps are particularly useful in identifying the location of testing domains, such as creep and tensile tests, in relation to the stress-temperature-strain rate domains experienced by NiAl.

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Plastic flow response, microstructure evolution, and defect formation during the primary hot working of conventional alpha/beta titanium alloys and gamma titanium aluminide alloys with two–phase lamellar colony microstructures are reviewed. The effects of initial grain/colony size, deformation rate and temperature on constitutive behaviour and the mechanisms associated with the observed flow softening are discussed. The kinetics of dynamic globularization are summarized and interpreted in terms of measured constitutive response. In addition, the mechanisms underlying failure via shear localization and cavitation during breakdown metalworking operations are described.

Cavity initiation, growth, and coalescence phenomena during the hot tension testing of Ti–6Al–4V with several different transformed β-microstructures were established to obtain an understanding of the failure process during subtransus hot working. Samples with either a colony-type microstructure (containing grain-boundary α) or a martensitic, acicular α-microstructure were pulled to failure at strain rates between 0.01 and 3 s−1and various subtransus temperatures ranging from 540 to 955°C. Metallographic analysis of sectioned tension samples with colony microstructures revealed that cavity initiation occurred at very low strains (≾0.2) irrespective of strain rate at temperatures below 900°C due to an apparent incompatibility of deformation between the grain-boundary α-layer and the Widmanstatten side plates. Initiation strains were somewhat higher (∼0.2–0.5) for samples with the acicular α-microstructure tested at temperatures below 900°C; however, failure was still intergranular. Subsequent cavity growth was more rapid for colony microstructures than that for the martensitic α-microstructure at these temperatures. Above 900°C, however, substantially higher cavity initiation strains and lower cavity growth rates were obtained for both microstructures. These latter behaviors were ascribed to the presence of a large volume fraction of ductile β-phase and moderate values of the strain-rate sensitivity of the flow stress, respectively.

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Production of acetyl esterase by Termitomyces clypeatus was stimulated by xylan, cellulose, arabinose and arabinose-containing polysaccharides in the growth medium. The culture filtrate was equally active with p-nitrophenyl acetate and acetyl xylan. Acetyl xylan was completely deacetylated by the enzyme. Activity was optimum at pH 6.5 and at 50¡C. The Km values for p-nitrophenyl acetate and acetyl xylan were 0.83 mM and 0.38% (w/v) with Vm of 48 and 55 mmole acetate produced/min.mg protein, respectively.

Mechanical properties at the interface between NiAl intermetallic and Mo ductile phase in sandwich laminates have been studied under a variety of stress states involving primarily shear. A shear/compression test for laminates of NiAl/Mo/NiAl has been used in which a double-notched specimen with cut-through metal interlayer is loaded to failure in compression. Because of the large elastic mismatch between NiAl and Mo, a primarily shear loading generates a significant amount of normal stress in this test. Interface shear response and toughness obtained using this technique are compared for NiAl/Mo laminates with interfacial segregant, Cr, Re and C layers fabricated by high temperature diffusion bonding. A microstructural investigation of the interfacial reaction zone and the shear failure path is conducted to identify failure mechanisms. Failure strength and related interfacial toughness is examined using an FEM model of local stress state close to the notch in the bimaterial shear/compression specimen geometry. A trend of increasing bond strength with reducing notch spacing is identified and analyzed in terms of local stress state, the onset of microyielding and crack shielding. Thus, a new fracture stress locus has been developed for bimaterial interfaces. Residual stress due to CTE thermal expansion mismatch is measured and the contribution of thermal residual stress to the failure behavior of the laminate is explored. The combined effect of stress concentration at crack tip, residual stress and slip discontinuity across interface have been used to explain the apparently brittle loading response and easy debonding of Mo fibers in eutectic NiAl/Mo alloys.

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Sulfur, introduced to a working Pt/KL. hexane aromatization catalyst in the form of thiophene, functions as an extremely potent poison by reducing the number of Pt sites accessible within the channels of the KL zeolite. The intrinsic catalytic activity and selectivity of in-channel Pt sites, however, is not significantly modified by the presence of sulfur on the catalyst. Extremely low thiophene feed sulfur concentrations in the 50-200 wppb range accelerate Pt agglomeration. Catalyst deactivation, resulting primarily from metals agglomeration, most likely occurs by multiple blockage of KL channels by small (10-20 Å) Pt and/or Pt-sulfur clusters.Copyright 1993, 1999 Academic Press

It is known that the highest critical currents in fine-filament NbTi conductors are obtained when the filaments are closely spaced. However, the filaments in a composite with a high-parity copper matrix tend to be coupled via the proximity effect as the filament spacing is reduced leading to large magnetization at low fields. To reduce the proximity coupling, trial billets of NbTi were fabricated with Cu-30% Ni matrix, Cu-0.5% Mn matrix and one with a Ni barrier around the filaments. Wires drawn from these billets have shown that this interfilament coupling can be suppressed for very-small filament separations. A full-sized commercial billet with Cu-0.5% Mn matrix demonstrated that high-critical-current-density conductors with filament size approximately 1-5 mu m can be fabricated which show no interfilament coupling at low fields.<>

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Bulk polycrystalline samples of Bi2Sr2CaCu2O8+x (Bi-2212) have been irradiated with 40 MeV α-particles. Tc increases up to a certain dose. The increase in Tc is correlated with the knock-out of oxygen, which has been verified by the determination of the oxygen contents of the irradiated samples by iodometry. A model of the knock-out of oxygen is proposed on the basis of Monte-Carlo TRIM calculations. Resistivity versus temperature of the irradiated samples shows fairly metallic behaviour up to a certain dose. Excess conductivity analysis shows a cross-over from 2D to 3D behaviour in conductivity for the unirradiated sample. However, for irradiated samples, the critical fluctuation regime sets in. The interlayer coupling strengths decrease with the increase in the irradiation dose. The sample with the highest dose shows a nonmetallic behaviour in resistivity. A detailed analysis shows a conductivity behaviour in the nonmetallic region characteristic of three-dimensional variable range hopping of charge carriers.

Feline alkaline phosphatase (FeALP) was copurified with the putative 70-kDa feline leukemia virus subgroup-A (FeLV-A) receptor protein from feline T-lymphhocyte cells (FeT) by two-dimensional gel electrophoresis. The sequence of the N-terminal 17 amino acids and five other internal tryptic peptides revealed that it is homologous to the liver/bone/kidney (L/B/K)-type alkaline phosphatase of other mammalian species. Corresponding oligonucleotides were synthesized and used for amplification of a 1.2-kb segment of the FeALP gene by polymerase chain reaction, using phage DNA from a FeT cell cDNA library as template. The 1.2-kb FeALP gene fragment generated was then used as a probe to isolate a 2127-bp L/B/K-type FeALP cDNA clone from the same library harboring a large, intact open reading frame. This cDNA possessed an open reading frame encoding a 524-amino-acid protein including a putative signal peptide of 17 amino acids followed by 14-amino-acid residues identical to the N-terminal sequence determined from the purified protein. Sequences closely related to five tryptic peptides from the purified protein were also contained within the cDNA-encoded protein. Homology with the human, bovine, rat and mouse L/B/K-type ALP was found to be 88-90% at both the nucleotide and the amino acid levels. The cDNA was transferred into a eukaryotic expression vector and expressed following transfection into murine and mink lung fibroblast cell lines. High levels of enzymatically active ALP were detected, along with a 70-kDa protein reactive in immunoblot assay using a polyclonal antibody against the original crude FeALP preparation. FeALP was specifically released from intact cells by treatment with phosphoinositol-specific phospholipase-C. By Northern blot analysis, only one species of mRNA was detected using a 32P-labeled cDNA probe. These results indicate that the 2127-bp cDNA encodes a functional feline L/B/K-type ALP expressed on cell surfaces via phosphatidylinositol-glycan linkage. Despite electrophoretic comigration in two dimensions and following deglycosylation in a third dimension, FeALP failed to function as an FeLV receptor since its expression failed to provide for attachment or entry of virus into cells.Copyright 1995, 1999 Academic Press, Inc.

Termitomyces clypeatussecreted a 24‐kDa xylanase constitutively in xylan medium, but required a gluconeogenic amino acid or Krebs cycle acid for the secretion of a 56‐kDa amyloglucosidase in dextrin medium. Aspartate, glutamate, succinate and fumarate all increased secretion of amyloglucosidase from 50% to >90% and enzyme production by 10‐fold with little effect on xylanase production. Glutamate or succinate stimulated in vitro release of intracellular amyloglucosidase from washed mycelia in the presence of cycloheximide. Amyloglucosidase accumulated in the absence of glutamate was a high‐molecular‐mass protein that did not migrate in PAGE. Cellular regulation by the fungus of the secretion of amyloglucosidase is indicated.

In statistical hydrology, three different methods have been used to calculate the expected values of observable quantities in an ensemble. The first is to use an observable as a parameter to characterize the “states” of the ensemble and then to calculate the average value of the observable over all possible states; this is the expected value. The second method is to use an observable as a parameter to characterize the “states” and then to designate the most probable value of the observable as the expected value; this is known as the “minimum variance principle”. Finally, the third method is to use a parameter different from an observable to characterize the “states” and then to take the value of the observable for the most probable state as the expected value. Of all these different methods, only the first one is, in principle, physically correct. Thus, a study was made to determine the situations where methods other than the first can be used to calculate the expectation values of observables. It was found that this can be done only in those situations where all of the following conditions hold: (i) The number of parameters used to characterize the states is finite; (ii) these parameters are either the same as the observables or are explicitly related to the observables; and (iii) each of the parameters has a symmetrical and unimodal probability distribution. The cases where the minimum variance principle is valid, are thereby delineated.

AbstractThe note describes the results of finger and palmar dermatoglyphics of the Lyngam tribe of Meghalaya, India.

AbstractMorpho-genetic traits such as earlobe attachment, mid phalangeal hair, relative lengths of toes, hand clasping, arm folding, tongue rolling and tongue folding of the Dalu, of Meghalaya are reported. The results of the present study are compared with other popullations in order to assess the group difference or similarities. The present Dalu sample stand significantly apart from most of the populations under considertaion.

AbstractThis note reports the frequency distribution of digital formulae and other morphological character of foot among the Lepcha of Kalimpong sub-division. West Bengal.

AbstractThe present genetic study was conducted among the Dalu individuals of Meghalaya. The genetic traits reported here include ABO blood groups. Rh factor. PTC taste sensitivity and colour blindness. The present findings have been compared with the neighbouring populations.

AbstractOn the basis of ABO blood groups, Rh factor, PTC taste sensitivity and colour blindness it is suggested that the Lyngam seems to be ethnically a distinct population. The present findings are discussed in detail in the light of available data on the neighbouring allied groups of Meghalaya, India.