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Benefiting from the advantages of low cost, light weight and mechanical flexibility, piezoelectric nanogenerators have the potential for application in renewable energy harvesting from various unexplored sources. Here, we report the demonstration of the record efficiency of flexible piezoelectric nanogenerators (PENG) using composites of polyvinylidene fluoride (PVDF) and chemically exfoliated tungsten disulfide (WS2) nanosheets, which are found to be strongly photosensitive, making them attractive for self-powered optical devices. The presence of two-dimensional (2D) WS2 nanosheets in the PVDF matrix plays a dual role in enhancing the nucleation of the electroactive β-phase as well as inducing strong photosensitivity in the nanocomposite. The PVDF-WS2 composed flexible device is able to produce an enormously high output voltage of ∼116 V (for an impact of 105 kPa) and a piezoelectric energy conversion efficiency of ∼25.6%, which is the highest among the reported values for PVDF-2D material based self-poled piezoelectric nanogenerators. This self-poled piezo-phototronic device exhibits strain-dependent photocurrent at zero bias and exhibits a responsivity of 6.98 × 10−3 A W−1 at 0.75% strain under the illumination of 410 nm. The fabricated PENG is also able to harvest energy from routine human activities (finger tapping, writing on paper, mouse clicking, etc.) and movement of human body parts. These results open up a new horizon in piezo-phototronic materials through the realization of photosensitive multifunctional PENGs, which can be scaled up for fabricating compact, high performance, portable and self-powered wearable electronic devices for smart sensor applications.

Selective separation of 99Tc from aqueous process streams is of vital importance in view of its high fission yield, radioactivity, the long half-life, and high mobility in the environment. To this ...

A simple and scalable technique is reported to demonstrate self-poled, flexible and superior-performance piezoelectric nanogenerators by using chemically exfoliated layered MoS2 nanosheets embedded...

Local and long-range structural properties, of sol-gel synthesized, Ce1-xNixO2 (0 ≤ x ≤ 0.1) nanopowders have been investigated. Substitution of Ce4+ by comparably smaller Ni2+/Ni3+ ions leads to decrement in lattice parameters. UV–visible spectra reveal decrease of bandgap with increase of disorder upon increasing Ni substitution. The photoluminescence (PL) spectra reveal five major peaks attributed to various defect states. Ni substitution results in the creation of oxygen vacancies (VO) which further leads to conversion of considerable amount of Ce4+ ions to larger size Ce3+. These changes notably, modify the structure of the host lattice. The defects created along with the structural modifications bring, changes in the PL emission. The disorder in the lattice results in increase of non-radiative decay which reduces the PL emission. An increasing VO and Ce3+ concentration at the surface acts as emission quenching centers. Lattice disorder and VO quantities were estimated using X-ray absorption (XAS), UV–vis and Raman spectroscopy.

We report on the characteristics of mechanically flexible, stable and photoactive triboelectric nanogenerators based on two-dimensional graphitic carbon nitride (g-C3N4) nanosheets. The performance of nanogenerator devices has been studied with varying frictional surfaces (such as polypropylene, aluminium oxide, Teflon and polyethylene terephthalate). Energy band diagrams have been used to explain the mechanism of triboelectric charge transfer in pristine and doped g-C3N4, with the former showing better characteristics. An optimized device has been found to be responsive to external stimuli to generate an output voltage of 10 V upon simple biomechanical impulses. To demonstrate the efficacy for practical applications of g-C3N4-based triboelectric nanogenerators, output voltages have been recorded for different common activities like walking, water showering, using as a writing/drawing pad, etc. Repetitive finger tapping on a device could charge a capacitor to as high as 55 V within ∼50 s, while that under UV illumination is found to be much faster (∼14 s) due to photoinduced carrier generations in g-C3N4. The exhibition of a superior photoresponsivity of ∼117 V W-1 under UV illumination demonstrates the dual functionality of g-C3N4-based triboelectric devices as a nanogenerator as well as an active flexible photosensor, which is hitherto unreported. Excellent mechanical flexibility, stability and photoinduced enhancement of output characteristics make g-C3N4 an attractive candidate for nanogenerator devices for future applications.

The anatase to rutile phase transition of TiO 2 which normally occurs at 750 °C, is reduced to temperatures below 600 °C by vanadium doping. The structural transformation is observed by a systematic study in the temperature range from 450 °C to 750 °C. The introduction of vanadium in rutile lattice is found to have impact on lattice parameters and particle size. This substitution also helps to reduce the bandgap of rutile TiO 2 to 1.76 eV from 3.04 eV upon 6 at% of vanadium doping. Vanadium induces additional donor level in forbidden region. XANES study confirms that vanadium is in mixed valence state of V 4+ and V 5+ and concentration of V 4+ increases with increasing doping amount and in the band gap region donor level due to V 4+ takes deeper position than V 5+ . As a result, the effective band gap decreases with increasing vanadium concentration. Anharmonicity of vibrational modes systimatically increases which indicates increasing phonon-phonon interaction with increasing doping concentration.

In the recent years of innovations hydrogels plays important role in various industrial applications. Hydrogels with combination of natural polymers are widely used for its biocompatibility and ecofriendly nature such as pectin and carboxymethyl cellulose (CMC). Plasticizers are utilized to enrich the physicochemical characteristics of hydrogels based on natural polymers. Polyethylene glycol 400 (PEG 400) is known to render thermostability. Whereas copper ions has wound healing properties and acts as biocide. These hydrogels due to its high porosity can have various utility to entrap small particles such as dust, pathogens and other pollutants and can act as very good face mask. Therefore the fabricated hydrogel is not only thermostable but also have high cytocompatibility, pH sensitivity, porosity and degree of swelling.

Here we demonstrate novel self-powered photodetection using silver (Ag) nanoparticle-loaded two-dimensional graphitic carbon nitride (g-C3N4) nanosheets triggered by poly-vinylidene fluoride (PVDF)-based flexible piezoelectric nanogenerators. A self-poled PVDF-based nanogenerator has been obtained upon exploiting pristine g-C3N4 nanosheets as a filler material within the PVDF matrix. The fabricated nanogenerator devices are found to be highly efficient in generating the maximum voltage of ∼2.3 V and maximum power ∼110 μWatt/cm2, upon finger tapping. Further, the integration of an additional layer of plasmonic Ag nanoparticle-loaded g-C3N4 nanosheets, has led to a significant enhancement of photoresponse. The hybrid plasmonic nanogenerator (with a strain of ∼0.021%) has resulted in self-powered photodetection with a photo-to-dark current ratio of ∼60, as compared to the unstrained device (∼2.0). In contrast to the usual behaviour (positive photoresponse), the exposure of an ultraviolet light lowers the output current indicating a negative photoresponse reported for the first time in such a system. The origin of such negative photoresponse has been attributed to the screening of piezopotential of PVDF by photogenerated carriers of g-C3N4 nanosheets. On the other hand, visible light-induced positive photoresponse has originated from the increment in the current, indicating the useful role of Ag nanoparticles in plasmon-induced hot electron transfer process.

CeO2 has cubic fluorite structure which is modified due to oxygen content as well as external substituents. The oxidation state of Ce plays an important role in strain and related physical properties. Ce3+ being larger in size than the Ce4+ ion, one expects a change in band structure due to changes in bond length; substitution of Ce4+ by Co2+ in sol–gel prepared, homogeneous, single-phase Ce1−xCoxO2 (x ≤ 10) nanopowders. The lower valence states of Co2+ induces oxygen vacancies which transforms some Ce4+ to Ce3+. A careful study of oxygen vacancies, strain, bond length and related band structure changes, have been targeted in this study. The possibility of phonon participation in electronic transition has been discussed using Tauc plot. Ce3+ forms defect states, between valence and conduction bands. Lattice parameters decrease, but strain increases with substitution.

During civil, nuclear or defense activities, internal contamination of actinides in humans and mitigation of their toxic impacts are of serious concern. Considering the health hazards of thorium (Th) internalization, an attempt was made to examine the potential of ten rationally-selected compounds/formulations to decorporate Th ions from physiological systems. The Th-induced hemolysis assay with human erythrocytes revealed good potential of tiron, silibin (SLB), phytic acid (PA) and Liv.52® (L52) for Th decorporation, in comparison to diethylenetriaminepentaacetic acid, an FDA-approved decorporation drug. This was further validated by decorporation experiments with relevant human cell models (erythrocytes and liver cells) and biological fluid (blood) under pre-/post-treatment conditions, using inductively coupled plasma mass spectrometry (ICP-MS) and transmission electron microscopy (TEM). Furthermore, density functional theory-based calculations and extended X-ray absorption fine structure (EXAFS) spectroscopy confirmed the formation of Th complex by these agents. Amongst the chosen biocompatible agents, tiron, SLB, PA and L52 hold promise to enhance Th decorporation for human application.

La doped Bi2UO6 solid solutions of the general formula Bi2-2xLa2xUO6 (x = 0-0.05) were prepared by the solid state reaction of Bi2O3, La(OH)3 and U3O8 in a stoichiometric ratio. These solid solutions were characterized by X-ray diffraction, Extended X-ray Absorption Fine Structure (EXAFS) and X-ray Absorption Near Edge Spectroscopy (XANES) studies. It was found that La goes to the Bi sites of the Bi2UO6 lattice during the formation of these solid solutions. For further confirmation, a photoluminescence (PL) study on an iso-structural Bi1.96Eu0.04UO6 was performed, and this supports the above observation. The solid solutions were also probed by EPR studies. The PL and EPR studies suggest that there are doping induced oxygen vacancies in these solid solutions.

Identifying the oxidation state and coordination geometry of radioactive element like uranium is important to fully understand its toxicology and other harmful effect in environment. Strontium orthosilicate is taken as a model compound for that. Strontium silicate doped with 1.0 mol% of U has been synthesized using sol–gel method and characterized using X-ray diffraction (XRD), time resolved fluorescence spectroscopy (TRFS) and extended X-ray absorption fine structure (EXAFS). Uranium exhibits multiple oxidation state and each one of them is having characteristics luminescence is an interesting dopant from structural point of view. TRFS is used to investigate the oxidation state and coordination behavior of uranium in Sr 2 SiO 4 . From TRFS measurement it was observed that uranium stabilizes in +6 oxidation state in the form of uranyl ion. Based on luminescence lifetime and EXAFS studies it was inferred that uranyl is stabilized on both 9- and 10-coordinated strontium polyhedra but majority occupies relatively asymmetric 9-coordinated Sr sites. This is further confirmed using theoretical measurement.

Undoped and various rare earth ion doped SrZrO 3 (SZO) perovskite based phosphors have been synthesized using the gel-combustion technique employing citric acid as a fuel. The phase purity of the sample is confirmed by the X-ray diffraction (XRD) technique. It was observed that average particle size of perovskite particle was around 100 nm. In order to probe the local structure and symmetry around lanthanide ions in SrZrO 3 , detailed experimental investigation has been carried out. X-ray absorption near edge fine (XANES) measurements along with their respective emission spectroscopy confirm that on doping lanthanide ion; in cases they were found to get stabilized as trivalent species. Extensive time resolved emission spectroscopy (TRES) on doped samples shows that on doping Sm 3+ in SZO; an efficient energy transfer takes place and Sm 3+ ions are localized both in Sr and Zr positions of SZO. PL decay time shows the presence of two life time values in case of nanocrystalline SrZrO 3 :Sm 3+ : (i) Sm 3+ at Zr 4+ site ( τ =500 µs) and (ii) Sm 3+ at Sr 2+ site ( τ =1.2 ms) in the ratio of 3:1. Based on TRES for europium doped sample, it was inferred that, two different types of Eu 3+ ions were present in the SZO matrix. The first type was a long lived species present at relatively higher symmetric site of 'Sr 2+ ' and the second was a short lived species present at relatively lower symmetric 'Zr 4+ ' site which gets selectively excited at 296 nm. Dysprosium ion specifically occupies Zr 4+ site only in SZO. EXAFS studies supported the TRES results.

The present investigation is aimed at the feasibility of recyclability of polypropylene (PP) in injection moulding based on grey relational analysis. According to ISO 15270:2008, the recommended percentage of recyclability is maintained upto 25% by weight depending upon requirements. To qualify the products made up of polypropylene, besides rudimentary tensile strength at break and percentage elongation at break [ASTM: D638-03]; density [ASTM: D-792] and VSP (Vicat Softening Point) [ASTM: D-1525] were also considered, which are also very much needed to qualify products made up of PP. Virgin to recycled material ratio (V:R), injection pressure (IP), injection temperature (IT) and injection speed (IS) were the parameters dictating the product's quality and they all were taken at three levels. A Box-Behnken model of design of experiment was adopted to reduce the numbers of experiments instead of adopting full factorial layout. The raw material used for the experiments was Injection Grade Polypropylene Homomer (Grade: M-110) manufactured by M/s Haldia Petrochemicals Ltd. The specimens for the optimization were made as per ASTM-D 638-03-TYPE-I. To ascertain tensile strength and elongation at break, Universal Testing Machine (H100KS-0081) made by Hounsfield Test Equipment was used. VSP was determined by using microprocessor controlled HDT/VSP apparatus (model-MP3 Eod100/002, 20008305), made by Atsfaar, Italy. Density of PP sample is measured by using Dhona (200D, 29048). Grey Entropy method was adopted to ascertain the weights of the responses. It has been found that the V:R -1 -IT -1 -IP -1 -IV +1 yielded for the best quality product. Confirmatory tests were conducted to adjudge the response qualities. In abreast the authors conducted another experiment with 100% virgin material at IT -1 -IP -1 -IV +1 and they found upto 5% recycle material adulteration gives the similar response characteristics.

Objective Thoracic endovascular aortic repair, although physiologically well tolerated, may fail to confer significant survival benefit in some high-risk patients. In an effort to identify patients most likely to benefit from intervention, the present study sought to determine the risk factors for 1-year mortality after thoracic endovascular aortic repair. Methods A retrospective review was performed on prospectively collected data from all patients undergoing thoracic endovascular aortic repair from 2002 to 2010 at a single institution. Univariate analysis and multivariate Cox proportional hazards regression analysis were used to identify risk factors associated with mortality within 1 year after thoracic endovascular aortic repair. Results During the study period, 282 patients underwent at least 1 thoracic endovascular aortic repair; index procedures included descending aortic repair (n = 189), hybrid arch repair (n = 55), and hybrid thoracoabdominal repair (n = 38). The 30-day/in-hospital mortality was 7.4% (n = 21) and the overall 1-year mortality was 19% (n = 54). Cardiopulmonary pathologies were the most common cause of nonperioperative 1-year mortality (22%, n = 12). Multivariate modeling demonstrated 3 variables independently associated with 1-year mortality: age older than 75 years (hazard ratio, 2.26; P = .005), aortic diameter greater than 6.5 cm (hazard ratio, 2.20; P = .007), and American Society of Anesthesiologists class 4 (hazard ratio, 1.85; P = .049). A baseline creatinine greater than 1.5 mg/dL (hazard ratio, 1.79; P = .05) and congestive heart failure (hazard ratio, 1.87; P = .08) were also retained in the final model. These 5 variables explained a large proportion of the risk of 1-year mortality (C statistic=0.74). Conclusions Age older than 75 years, aortic diameter greater than 6.5 cm, and American Society of Anesthesiologists class 4 are independently associated with 1-year mortality after thoracic endovascular aortic repair. These clinical characteristics may help risk-stratify patients undergoing thoracic endovascular aortic repair and identify those unlikely to derive a long-term survival benefit from the procedure.

In the present study, we carried out for the first time the antioxidant and antiinflammmatory activities of the different solvent extracts of the plant Ipomoea pes-caprae (L) sweet grown up in the marine enviornment of the Sunderban Mangrove eco-complex. It was observed that chloroform and ethyl acetate solvent extracts obtained from the methanolic extract of the plant had significant antioxidant and antiinflammatory activities. To trace the molecules responsible for these bioactivities, the chemical investigation of the plant yielded four pure compounds, 7-hydroxy-6-methoxycoumarin; 5,7,4'-trimethoxykaempferol; 3,7,8,3'4'-pentahydroxy flavone; trans-[3-(4'-hydroxyphenyl)-2-propenoic acid] which were identified by spectral methods. These compounds when tested individually, showed appreciable radical scavenging activities.

Cystic echinococcosis (CE) caused by the larval stage ofEchinococcus granulosusis a disease that affects both humans and animals. In humans the disease is treated by surgery with a supplementary option of chemotherapy with a benzimidazole compound. During the present study heat-shock protein 60 (HSP 60) was identified as one of the most frequently expressed biomolecules byE. granulosusafter albendazole treatment. Data were correlated with 14-3-3 protein signature, and overexpression of this molecule after albendazole induction was an indicator of cell survival and signal transduction duringin vitromaintenance ofE. granulosusfor up to 72 h. This observation was further correlated with a uniform expression pattern of a housekeeping gene (actin II). Out of three β-tubulin gene isoforms ofE. granulosus, β-tubulin gene isoform 2 showed a conserved point mutation indicative of benzimidazole resistance.

In inner-shell ionization by heavy ions, a significant shift of X-ray lines to the higher energy side and broadening of the peaks indicate that simultaneous multiple ionization of the M and higher shells can dramatically change the values of the atomic parameters. 14 Si 3 , 4 + and 16 S 3 , 4 + ions in the energy range of 5–10 MeV were used to bombard gold (200 μg/cm2) and bismuth (80 μg/cm2) targets. Eight main M X-ray lines have been detected with a Si(Li) detector. Without a possibility for a realistic way to modify the atomic parameters and an accurate extraction of M-subshell ionization cross sections, theoretical cross sections for M-shell ionization are converted to X-ray production cross sections with two extreme choices that presume (i) no multiple ionization and (ii) the certainty that all shells outer to the M-shell are completely ionized in the full multiple ionization. These choices impose the lower and upper limits on theoretical predictions. The X-ray production data should be bracketed by the bounds calculated with any theory. We test this proposition by comparison of the measured cross sections for production of the main X-ray lines and their sum for the total M-shell X-ray production with the predictions of the First Born and ECUSAR [G. Lapicki, Nucl. Instrum. Meth. B 189 (2002) 8] theories in those two extreme limits. With the extreme assumption of no multiple ionization, the First Born approximation shows overall satisfactory agreement with the data while the ECUSAR theory drastically underpredicts our measurements. With the opposite extreme assumption of the full multiple ionization, the ECUSAR exhibits better agreement with the data than the First Born approximation. While neither agreement suggests sure preference for either of these theories, such extreme conversions – as they would have for of any ionization theories – set the lower and upper bounds on their predictions.

K x-ray satellites, hypersatellites and lines due to radiative Auger effect (RAE) of Ti, V, Cr, Mn and Fe were measured after exciting the samples with Ag bremsstrahlung at 35 kV. All the lines were measured with the ‘Spectroscan VY’ spectrometer of Spectron—OPTEL, Russia, in which a curved LiF(200) crystal was used. The spectra were deconvoluted using Voigt functions, and the peak positions of the satellites and hypersatellites were determined with errors of ± (1–5) eV. The energy shifts of the satellite lines with respect to their parent lines were also obtained. Multi-configuration Dirac–Fock (MCDF) calculations with the inclusion of higher-order corrections were carried out to predict the peak positions of the satellite and hypersatellite lines. Our data were then compared with our own calculated values and also with the data of others. Our measured energy shifts for KαL1, KαL2, Kαh and KβL1, when compared with our MCDF calculations, show a maximum deviation of 8, 12, 2 and 20% respectively. Copyright © 2008 John Wiley & Sons, Ltd.

Diamond like carbon (DLC) coatings were deposited on silicon(1 1 1) substrates by microwave electron cyclotron resonance (ECR) plasma CVD process using a plasma of Ar and CH4 gases under the influence of DC self bias generated on the substrates by application of RF (13.56 MHz) power. DLC coatings were deposited under the varying influence of DC bias (−60 V to −150 V) on the Si substrates. Deposited films were analyzed by different techniques like: X-ray photoelectron spectroscopy (XPS), spectroscopic ellipsometry (SE), atomic force microscopy (AFM), Hardness and elastic modulus determination technique, Raman spectroscopy, scanning electron microscopy (SEM) and contact angle measurement. The results indicate that the film grown at −100 V bias has optimised properties like high sp3/sp2 ratio of carbon bonding, high refractive index (2.26–2.17) over wide spectral range 400–1200 nm, low roughness of 0.8 nm, high contact angle (80°) compared to the films deposited at other bias voltages (−60 V and −150 V). The results are consistent with each other and find august explanation under the subplantation model for DLC growth.

Bremsstrahlung from an X-ray tube was used to excite secondary targets of Ag, Sn, I and Ba to get nearly monochromatic excitation energies of 22.6, 25.8, 29.2 and 32.9 keV, respectively. Th and U were used as targets. The L X-ray fluorescence cross sections of different lines from the targets have been measured. Of the several methods to obtain L subshell photoionisation cross sections from these fluorescence data, the merits and demerits of four common methods have been explained and the method with least uncertainty was suggested as the best one for such analysis. Following this method, with intensities of the resolved L γ lines, three L subshell photoionisation cross sections have been obtained using six different sets of atomic parameters. The variation of these cross sections with different atomic parameters has been discussed. For σ 1 , all the derived values are within 30% of one other while for σ 2 and σ 3 , they are within 12%. Measured cross sections have been compared with the data of others and with the theoretical values of Scofield. Finally, the intensity ratios of different L lines have also been compared with available data and the theoretical values. Within experimental errors, our data are in good agreement with the data of others and with the theoretical predictions.

Fats, particularly saturated fats, are always considered to be health hazard due to its link with cholesterol level in blood, as evidenced by Framingham study. Raheja observed that in mid seventies of the past century Indians developed a strong belief that cholesterol in blood was the main offender leading to heart diseases latter on and changed the dietary patterns, particularly oil medium to poly unsaturated fatty acids rich oils like sunflower oil or safflower oil etc. taking these as cholesterol reducers. Different workers reported that optimum quantities of different groups of fats are essential for maintenance of health. It was found that the quality of fats and the life style patterns were most important in causing the diseases particularly type 2 diabetes mellitus and other related diseases like hypertension, coronary heart disease, dyslipidaemia, obesity. The paper shows the importance of lifestyle patterns in rural Bengalese in causing the disease and observed that their dietary fat intake was not detrimental to health of diabetics.

Non-insulin-dependent or type 2 diabetes mellitus is on the rise in India particularly in the affluent urban and rural population. The exact cause is unknown. Malnutrition, defective intake of essential fatty acids and reduced intake of fibres are found in Indian diet, particularly rural Indian diet and the dietary factors may be one of the causes leading to increased incidence of the disease. Dietary fibers reduce blood glucose and cholesterol levels. Resistant starches behave as dietary fiber. As rice is the staple food in Indian villages, to increase the fibre consumption, a special variety of rice is processed which contains more of resistant starch. The high protein efficiency ratio (PER) in rice is presumably due to the balance of essential amino acids in rice protein. This high resistant starch containing rice was fed to diabetic patients for three months and effects observed. Results showed that total cholesterol, fasting blood sugar, low-density lipoprotein cholesterol were reduced while other parameters showed no significant changes.

A helium jet coupled Isotope Separator On Line (ISOL) facility has been designed and developed at Variable Energy Cyclotron Centre (VECC), Kolkata, for the study of nuclei away from the line of β -stability. The 6.2 m long Quadrupole-Quadrupole-Dipole (QQD) system has been designed for a dispersion of 2.52 m for 100% rigidity change. A typical FWHM mass resolving power of around 900 has been measured in high temperature surface ionisation mode. The design and development of the facility and the first test experiment will be reported in this article.

We have studied microstructural, magnetic and electrical transport properties of melt-spun Cu90Co5Fe5 granular alloys. XRD results show the phase formation and the decomposition of the Cu–Co (Fe) solid solution, occurred by the annealing of the samples at a certain temperature. AFM (atomic force microscopy) investigation demonstrates the distribution of particles size and MFM (magnetic force microscopy) directly shows the ferromagnetic granules on the copper matrix. These results are corroborated by the magnetic properties of the samples. Magnetic and electrical transport properties have been studied in the temperature range 15–300 K through ac susceptibility and dc resistivity measurements in the presence of magnetic field. The measured magnetoresistance of the samples reaches the highest value at an optimum annealing temperature.

The graft copolymerization of acrylic acid onto isotactic polypropylene has been investigated. The grafting was carried out using benzoyl peroxide initiator. Grafting is essentially a surface phenomenon and takes place, mostly, in amorphous region of the fiber. Emphasis, therefore, was placed on various pretreatment techniques for swelling of the fiber, viz, pretreatment with toluene and 1,1′2,2′tetrachloroethane, ultrasound, and photoirradiation. Process parameters, characterization study such as IR spectroscopy, TGA, and DTA, and properties such as tensile properties, melting temperature, dyeability towards basic dyes, and ion exchange properties were investigated. Benzene was found to be the most suitable solvent for initiator as against the acetone. Tenacity was found to be increased with increase in graft yield and reached to maximum at about 5% graft add-on, and then decreased with further increase in graft add-on. Proportionally, a converse effect was reported in the study of elongation to break. Thermal stability of polypropylene was found to be improved because of grafting. The grafted polypropylene also showed satisfactory dyeability toward basic dyes and also exhibits very good ion exchange properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1152–1165, 2007

K to L shell vacancy transfer probabilities ( η KL ) of Mo, Pd, and Cd have been measured by successively exciting them with the K X-rays of Ni and Sn induced by the bremsstrahlung emanating from an X-ray tube. The measured values of η KL agree well with the theoretical values and the data of others.

L X-ray fluorescence cross sections of the elements with Z = 62, 64, 66, 68 and 70 have been measured at 17.8, 22.6 and 25.8 keV using an X-ray tube and secondary exciters of Mo, Ag and Sn. The measured cross sections have been compared with the theoretical predictions and with the data of others. Theoretical values calculated using photoionisation cross sections from Scofield [Lawrence Livermore Laboratory, UCRL-51326, 1973], fluorescence yields and Coster–Kronig transition probabilities from Puri et al. [X-ray Spectrom. 22 (1993) 358] and radiative widths from Campbell and Wang [At. Data Nucl. Data Tables 43 (1989) 281] show good agreement with our data. Except two sets of data on Lγ cross sections, all the data of other groups agree well with those of ours.

This paper describes, for the first time, a simple sonochemical method for the synthesis of nanoparticles of a series of rare earth orthoferrites. This sonochemical process is enabling synthesis of nanoparticles of the rare earth orthoferrites at a substantially lower calcination temperature by using simple precursors, iron pentacarbonyl and rare earth carbonates. It is particularly noteworthy that the cogeneration of the garnet phase has not been observed, as is usual with the conventional methods. The drastic reduction in the calcination temperature could be due to the ultrasonic generation of amorphous iron oxide from Fe(CO)5. Nanosized GdFeO3, ErFeO3, TbFeO3, and EuFeO3 were prepared by this method and their magnetic properties were also studied in detail.

This paper demonstrates that samples can be directly exposed to an X-ray tube bremsstrahlung to obtain their elemental composition. For this purpose, the bremsstrahlung spectrum from an X-ray tube has been detected with a Si(Li) detector. A theoretical spectrum was generated which fitted well with the experimental one. Four samples of known composition were then irradiated in the tube bremsstrahlung. A computer program was developed to obtain the elemental composition of the samples. Results obtained by this method (without the necessity of using any standard sample) were found to be in good agreement with our earlier findings.

Complexes of the [AILCl2], [ML(OH)Cl] and [M′LL′(H2O)Cl] type, where HL = 5-bromouracil; HL′ = histidine; M = CrIII or FeIII and M′ = AlIII, CrIII or FeIII were synthesized and characterized. The complexes are polymers with high temperature decomposition points and are insoluble in H2O and common organic solvents. 5-Bromouracil is coordinated to the metal ion through the O atom of C(4)=O and the N atom of N(1), while histidine coordinates through the O atom of —CO2− and the N atom of the —NH2 groups. The μeff values, electronic spectral bands and e.s.r. spectra suggest a polymeric six-coordinate spin-free octahedral stereochemistry for the CrIII and FeIII complexes. The in vivo antitumour effect of 5-bromouracil and its complexes was examined on C3H/He mice versus P815 murine mastocytoma. As is evident from their T/C values CrIII and FeIII complexes display significant and higher antitumour activity compared to 5-bromouracil while the AlIII complexes show lower activity. The in vitro results of the complexes on the same cells indicate that CrIII and FeIII complexes show higher inhibition on 3H-thymidine and 3H-uridine incorporation in DNA and RNA replication, respectively.

A fine strontium hexaferrite powder has been successfully synthesized by a sonochemical method employing Fe(CO)5 and SrCO3. SrCO3 was first synthesized using strontium nitrate and urea, and it was found that applying ultrasound radiation during this process results in the uniform formation of SrCO3 hexagonal rods. These rods were then dispersed with in situ generated amorphous Fe2O3, using Fe(CO)5 as the source. The resultant precursor was then calcined at 900°C, which is lower than the conventional solid-state reaction of applying 1300°C to get the strontium hexaferrite fine powder. This sonochemically derived ferrite exhibited an intrinsic coercivity of ∼4600 Oe and a saturation magnetization of ∼60 emu/g at 20 K and ∼32 emu/g at 300 K.

Ba x Sr 1− x TiO 3 (BST) thin films have been deposited by rf magnetron sputtering on multi-layered perovskite conducting bottom electrode with or without a buffer layer on Si. The crystallinity and surface morphology of the deposited films have been studied using X-ray diffraction and scanning electron microscopy. Electrical properties of the BST films have been evaluated on multilayer oxide electrode using Si/MgAl 2 O 4 /LCMO/BST/Al metal-insulator-metal structure. The bottom electrode interface has shown a marked effect on the electrical properties of the BST films. Current–voltage behavior has indicated the Poole–Frenkel conduction mechanism at higher voltages.

BaxSr1−xTiO3 (BST) thin films have been deposited by r.f. magnetron sputtering on silicon and platinum-coated silicon substrates with different buffer and barrier layers. Electrical properties of BST films have been evaluated using both metal–insulator–semiconductor (MIS) and metal–insulator–metal (MIM) structures. MIS capacitor C–V and G–V characteristics have been utilized to determine the fixed charge density, interface trap density and the trap distribution in the silicon bandgap. BST films deposited on Si/SiO2/SiN/Pt and Si/SiO2/Ti/TiN/Pt multilayer bottom electrodes have been used for the fabrication of MIM capacitors. The role of bottom electrode, processing temperature and Ba to Sr ratio on the electrical properties of BaxSr1−xTiO3 films have been investigated. Current–voltage behavior has indicated an ohmic nature at lower voltages and Poole–Frenkel conduction at higher voltages. Deposited films have shown an excellent time-dependent dielectric breakdown under constant-current stressing.

Vanadium incorporation in ZnO modifies the lattice structure. The valence state of V plays an important role, controlling the oxygen content and thereby dimensions of the lattice. Both V4+ and V5+ are more electropositive than Zn2+ and reduce oxygen vacancies, resulting in lattice expansion. However, the sizes of both V4+ and V5+ are smaller than Zn2+, thereby resulting in the lattice contraction. The internal competition of increasing oxygen content and reducing effective crystal radius decides the lattice expansion and contraction. This affects the lattice strain and changes electronic levels, which modify absorption and emission processes in between the valence and conduction bands. A strong green emission band not due to oxygen vacancy but due to defects contributed by vanadium is also dependent on the oxidation state of vanadium. Bandgap also increases with the increase in the V4+ content.

© 2014 Elsevier B.V. All rights reserved. Nano-structures are often sought to be constructed from some especially stable multifunctional unit which can be manipulated into different desired forms. To this end an icosahedral borane or carborane unit is considered as a basic icosahedral building block, to build further larger nano-structures. A potential is noted for the formation of a sort of super-carborane unit, comprised of 12 carboranes at the nodes of a large icosahedron. A further possibility involves taking 12 of these icosahedrons at the corners of an even larger icosahedron, to yield a super-super-carborane structure - perhaps with acetyleneic linkages between the super-carborane units.

The degumming action of ramie with sodium metasilicate, alone or in combination with other alkali solutions such as sodium carbonate and trisodium phosphate, has been evaluated and optimum conditions determined. The performance of degumming has been assessed in terms of weight loss, whiteness index and colour strength of the degummed fibres.

M shell X-ray production cross-sections of Au and Pb induced by 0.33–1.0 MeV/u C2,3,4+ ions are reported. The results are compared with the predictions of the first Born and ECPSSR theories. The first Born predictions are in fair agreement with the measured values, while the ECPSSR calculations are by a factor of 2–5 lower than the data.

Weak-link behaviour of YBa 2 Cu 3 O x (1 2 3) superconductors sintered in different atmospheres are studied by measuring the variation of critical current densities ( J c ) near the superconducting transition temperatures ( T c ). The weak links are found to change from superconductor–insulator–superconductor to superconductor–insulator–metal–superconductor and superconductor–metal–superconductor type of junctions as the sintering atmosphere is varied from argon to air and oxygen respectively. The scanning electron microscopy in conjunction with energy dispersive spectroscopy studies indicate that the composition fluctuation at the grain boundaries is the reason for such variation.

The effect of post-deposition annealing on the structural and optical properties of barium strontium titanate, Ba0.8Sr0.2TiO3 film has been investigated. The films have been deposited on oxidized p-silicon substrates by r.f. magnetron sputtering followed by annealing in O2 atmosphere at different temperatures. In situ deposition has also been carried out at 550 °C for comparison. The nature of the variation of refractive index and extinction coefficient with annealing temperature and wavelength has been studied. Absorption band edges shift towards lower photon energy values as the temperature is increased causing a reduction in the optical band gap energy. Infrared absorption bands show a cubic symmetry at lower frequency and are found to be broadened and even split at higher frequency.

A dilute aqueous solution of flavocytochrome b2 when exposed to inactivating doses of UV radiation at 280 nm underwent reversible loss in activity both under aerated and deaerated conditions. The active site as well as the substrate binding sites were found to be modified in the irradiated enzyme. Irradiation of the enzyme in the UV-C range resulted in partial unfolding of the polypeptide framework. Destruction and/or modification of both tryptophan and tyrosine residues as well as heme moieties took place. Preliminary laser flash photolysis studies suggest that the initial photo-ionization takes place with tryptophan and tyrosine residues with the formation of excited states and radicals, and then rapid transfer of electrons takes place to histidyl and cystinyl sites which might have eventually been altered in the process.

Steady state gamma irradiation of an aqueous solution of flavocytochrome b2 under different conditions led to modification of tryptophan and tyrosine residues. These aromatic amino acid residues were more susceptible to the attack by OH radicals than H atoms. Unchanged quantum yield values for tryptophan and tyrosine residues and unchanged tryptophan excited state lifetime in the irradiated enzyme suggests that irradiation results in breakage of some non-covalent bonds disrupting the peptide framework partially. It is justified by the circular dichroic studies for the irradiated enzyme which shows a reduced helicity but no evolution towards any other structures.

Hard-facing of glass fibre was done by pyrolysis of boric acid and triethanol amine condensation product under air atmosphere. Characterization of the condensation product and its pyrolysed form was done by NMR, IR and X-ray diffraction (XRD). Characterization of the pyrolytically coated fibre was done by XRD and ESCA. It was observed that the coating is smooth, bubble-free and amorphous in nature and suitable for refractory applications.

The sintering characteristics of Y–Ba–Cu–oxide (YBCO)–Agx (x = 0 to 1.2) using thermomechanical analyzer were systematically investigated to understand the sintering mechanism of the metal superconductor composites. The addition of Ag was observed to lower the sintering temperatures, and the apparent densities of the sintered compacts increased with x from 0 to 0.6. A further increase of x above 0.6 decreased the apparent densities of the sintered compacts. The presence of Ag globules in the YBCO–Ag compacts was observed by scanning electron microscopy and energy dispersive x-ray spectroscopy. The apparent activation energies for sintering of the powder compacts were estimated and observed to vary between 900 to 2000 kJ/mol. The formation of AgOx by absorbing oxygen from YBCO and sintering atmosphere possibly controls the sintering and superconducting behavior. Incorporation of Ag into the matrix modifies the weak-link characteristics from superconductor–insulator– normal–superconductor (S–I–N–S) to superconductor–normal–superconductor (S–N–S) type.

In the case of acylation reaction of aromatic hydrocarbons it is observed that acylation of toluene and naphthalene in the presence of acidic zeolites such as H–ZSM-5, H–ZSM-12, H–Beta, H–Mordenite, and H–Y results in different products with variable selectivities. It is observed experimentally that benzoylation of toluene and naphthalene over zeolite H–Beta follows the selectivity order: 4-methylbenzophenone>2-methylbenzophenone> 3-methylbenzophenone and 2-benzoylnaphthalene>1-benzoylnaphthalene, respectively. Zeolite H–Beta shows the best selectivity among all other acidic zeolites. To explain this selectivity order a computer simulation study has been performed. Molecular mechanics were used to calculate the individual strain, dimensions of reactant, and product molecules; the dimensions of zeolite cages were compared. The results show that zeolite Beta is the best zeolite in terms of fitting of the reactant and product molecules. DFT was applied to study the electronic property and interaction energy of reactant and product molecules with acidic zeolite framework to rationalize the mechanism of acylation reaction over acidic zeolites. Molecular electrostatic potential maps were also plotted from DFT to rationalize the polarization of the reactants in the reaction process. The results were compared with experimental observation which justifies the role of acidic zeolites, in this particular reaction.

1,2,3,4‐tetrahydrocarbazole (CAR) has been synthesized over H‐ZSM‐12, H‐beta, H‐mordenite, H‐Y, H‐ZSM‐22, H‐EU‐1, H‐ZSM‐5 and acetic acid by Fisher's method using phenylhydrazine and cyclohexanone. H‐Y is more active than the other zeolites studied for the synthesis of CAR. The influence of different parameters such as the duration of the run, catalyst concentration, reaction temperature and molar ratios of the reactants in the synthesis of CAR are also studied. A number of arylhydrazines such as o-tolylhydrazine, p-tolylhydrazine and 1,1‐diphenylhydrazine and cyclic ketones such as cyclopentanone, cyclohexanone and 3‐methylcyclohexanone have also been taken to study the effect of substitution in phenylhydrazine and the size of the cyclic ketones in the reaction. The yields of indoles correlated with the degree of substitution of the reactants and products, and the limitations imposed on diffusion through zeolite pores.