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The low ionic conductivity and electrode–electrolyte interface instability issues with solid polymer electrolytes jeopardize their electrochemical performances in lithium-ion batteries (LIBs). The use of quasi-solid-state electrolytes (QSSEs) with concentrated Li salt embedded inside the pore networks of metal organic frameworks (MOFs) can successfully address the aforementioned issues. Owing to the sieve effect of zeolitic imidazolate framework-8 (ZIF-8) towards selective cation permeability over anions through the interconnected pore network, a unique QSSE with LiTFSI salt concentrated in the ZIF-8 skeleton used as a filler in poly(ethylene oxide) has been synthesized. LiTFSI gets embedded inside the interconnected pore network of ZIF-8 that furnishes unhindered pathways for Li+ ion migration leading to a very high ionic conductivity of ∼6 × 10−4 S cm−1. The higher ionic conductivity is directly related to the Li+ ion conduction through the pore network of ZIF-8 which has been experimentally evident from complementary methods viz. Positron annihilation and broadband dielectric spectroscopy. The design route towards these types of QSSEs encompassing porous MOFs paves the way for realizing Li superionic conductors suitable for practical application in commercial LIBs with high safety and stability. [ABSTRACT FROM AUTHOR]

Although cubic ice (ice Ic) is considered to be an important phase of water that impacts ice cloud formation in the Earth's upper atmosphere, its properties have not been studied to the same extent as those of hexagonal ice (ice Ih). This is because pristine ice Ic is not formed in simple laboratory conditions. Ice Ic formed in ambient conditions has a stacking disordered array of both hexagonal and cubic-structured hydrogen-bonded water molecules. It is therefore an active area of research to find ways of developing stacking disorder-free pure ice Ic. We demonstrate the evolution of almost pure ice Ic structure within the spherical nanopores of a hydrostable Cr-based metal–organic framework MIL-101(Cr) with an average pore size of 1 nm by low-temperature neutron diffraction study on D2O. It is observed that at temperatures below 230 K a fraction of liquid D2O transforms into ice and more than 94% of ice crystals evolved inside the pore are cubic in shape. This is a significantly high fraction of ice Ic formed under simple conditions inside the spherical pores of a Cr-based MOF. It is also observed that upon increasing the temperature, ice Ic remains stable until its melting point, without being transformed into ice Ih. This observation is in contrast to our previous observation of ice structure in the 2D cylindrical nanopores of MCM-41, where H2O ice after creeping out from the cylindrical channel was seen to be dominated by hexagonal shape. In the present study, the D2O molecules were confined into well-defined spherical nanopores, which hindered the growth of crystals above a certain size, thus minimizing the stacking disordered array. Nanoconfinement of water inside uniform spherical pores is therefore a promising method for the evolution of a significantly large fraction of cubic ice by minimizing the stacking disorder. This finding may open up the possibility of forming ice Ic with 100% cubicity under simple laboratory conditions, which will help in exploring the microphysics of ice cloud formation in the upper atmosphere. [ABSTRACT FROM AUTHOR]

The (n,2n) reaction cross-sections of 154Sm, 150Nd and 82Se isotopes at 14.6 MeV neutron energy have been measured by neutron activation followed by off-line gamma-ray spectrometry with improved experimental methodology. The neutron flux was determined using the 197Au(n, 2n)196Aug monitor reaction which has not been used earlier for cross-section measurement for the above mentioned nuclei. The measured reaction cross-sections are found to have good agreement with calculated cross-section data, obtained independently, using Talys and ENDF codes. A detailed comparison of the present cross-section data with the existing literature has been presented in this paper. [ABSTRACT FROM AUTHOR]

Beam current monitoring or normalization is an important aspect in ion beam analysis utilizing particle accelerator for materials characterization. We present an innovative idea of using 29Si, present in the sample, as an internal beam current normalizer for the quantification of low Z elements by particle induced gamma ray emission (PIGE) method. The current normalized count rate of analytes (Si, Na, Mg, Al and/or B) with respect to prompt gamma-ray at 1273 keV from nuclear reaction 29Si(p,p′γ)29Si is utilized for the concentration determination. Quality control exercise was carried by analyzing certified/standard reference materials of sodalime and borosilicates glasses. Cross validation of proposed method was carried out by analysing two different glass samples by three different methods namely in situ current normalized PIGE method using fluorine as current normalizer, external PIGE using tantalum as current normalizer and ED-XRF. Analysis of variance and student's t test were performed to examine the reliability of the results. The optimized method was applied for chemical characterization of forensically important automobile windshield glass samples. [ABSTRACT FROM AUTHOR]

Coal is an important energy source and its quality evaluation in terms of the ash content and amounts of other elements, like B and F, is a necessity. An external (in air) particle-induced gamma-ray emission (PIGE) methodology using a low-energy proton beam (3.5 MeV) has been standardized for the simultaneous quantification of light (low-Z) elements, namely Si, Al, Mg, Na, F and B, in coal, bottom ash, and coke samples. Current normalization for sample and standard analysis was carried out externally using gamma-rays from a tantalum window, which was used for beam extraction in air. Upon utilizing tantalum current normalization, uncertainty when determining concentrations was improved compared to conventional in situ current normalization. The method was validated via analyzing standard/certified reference materials (SRMs/CRMs). The external PIGE method was found to be suitable, simple, and non-destructive for quantifying low-Z elements in complex matrices like coal, even at trace concentration levels (B and F). The prompt gamma rays emitted from 10B and 11B were utilized for the accurate determination of B with none of the volatilization issues encountered when using wet-chemical methods. The detection limits toward B and F in coal were found to be as low as 2 mg kg−1 and 90 mg kg−1, respectively, using the external PIGE method, which is reported here for the first time. As a quality assurance feature, the ED-XRF method was utilized for quantifying major elements (Si, Al, Mg, and Na), including Fe and Ca. Low-Z elements (Si, Al, Mg, and Na) and elements like Fe and Ca are helpful for determining coal quality in terms of the ash content, building on various other related studies using Al, Na, F, and B. From the results of PIGE and ED-XRF, the ash content levels in coal and coke samples were calculated based on the addition of the concentrations of Si, Al, Mg, Fe, Ca, and Na oxides. [ABSTRACT FROM AUTHOR]

Complexation study of acetohydroxamic (AHA) ligand with La(III), Nd(III), Eu(III), Er(III), and Lu(III), as representative of lanthanide (Ln) series, has been described, in presence of pure nitrate and combination of nitrate and perchlorate ions using various spectroscopic analysis and density functional theory (DFT) calculations. Nuclear magnetic resonance (NMR) spectroscopy reports the bidentate mode of coordination of Z-Keto tautomer of AHA monomer with La(III). Formation of 1:3 Nd(III)-AHA complexes in presence of pure nitrate and a combination of nitrate and perchlorate ions has been observed from ultraviolet-visible (UV-Vis) spectroscopy analysis. The geometrical parameter analysis exhibit the bidentate mode coordination fashion of the AHA monomer which corroborates the NMR results. The geometrical parameter, frontier orbital(HOMO-LUMO), global reactivity descriptors and local reactivity descriptors analysis supports the findings of the spectroscopy titration methods that stability of Ln-AHA complexes decreases in the presence of pure nitrate ions than in presence of both perchlorate and nitrate ions. The trend of theoretical NMR chemical shifts of AHA and La(III)-AHA complexes support the experimental NMR chemical shifts. This work helps to measure subtle differences in complexation behaviour of AHA with Ln in presence of pure nitrate and a combination of nitrate and perchlorate ions quantitatively, providing information about the Ln-AHA structural environment. Various spectroscopic methods (UV-Vis, NMR, and Fluorescence spectroscopy) and density functional theory (DFT) calculations have been implemented for structural characterization of lanthanides (Ln(III))-acetohydroxamic acid(AHA) complexes in the presence of a combination of both perchlorate and nitrate ions and in pure nitrate ions. The Ln(III)-AHA complexes show more stability in the presence of a combination of both perchlorate and nitrate ions than in the presence of nitrate ions which is supported by DFT calculations. [ABSTRACT FROM AUTHOR]

The recent observation of ferroelectricity in ultra thin films of hafnium oxide (HfO2) has been attributed to the orthorhombic (o) phase of HfO2 with space group Pca21. Although this oxide is polymorphic in nature, this polar o-phase is known to be stabilized in the doped thin film oxide. The objective of the present experiment is to stabilize the o-phases in La doped bulk polycrystalline HfO2 and investigate their evolution with the doping concentration through Time Differential Perturbed Angular Correlation (TDPAC), X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) measurements. The present work reports the presence of both the polar Pca21 phase and the antipolar Pbca phase at different La-concentrations. Two o-phases of HfO2 with space groups Pca21 and Pbca, difficult to distinguish by other complimentary methods, could be unambiguously identified by utilizing the atomic scale sensitivity of the electric field gradient (EFG) embedded in TDPAC spectroscopy. The determination of the oxidation state and the local environment of La-atoms by XANES and EXAFS measurements illuminates the microscopic role of the dopant in stabilizing the o-phase. The "solute drag model" proposes a critical crystallite size for the nucleation of the o-phase in bulk HfO2 and explains the role of the La-dopant in stabilizing the o-phase. Thus the present study shows the possibility of stabilizing the polar o-phase and hence attaining ferroelectricity in bulk HfO2 to augment the scope of future application for this ferroelectric device. [ABSTRACT FROM AUTHOR]

Pseudomyxoma peritonei (PMP), nicknamed "Jelly Belly", is a very rare disease characterized by presence of jelly like fluid called mucin in the abdominal cavity. The natural history of PMP revolves around the "redistribution phenomenon", whereby mucinous tumor cells accumulate at specific sites with relative sparing of the motile small bowel and to a lesser extent other parts of the gastrointestinal tract. This paper reports a case of an elderly woman, who was diagnosed with pseudomyxoma peritonei, who underwent surgery for the same and intraoperatively she was suspected to have primary arising from the ovary, postoperatively the histopathology report said that the primary was identified to be arising from the appendix. This also shines light on how cytoreductive and debulking surgery play a major role in prolonging the life span in such patients. [ABSTRACT FROM AUTHOR]

Introduction: Hypospadias is a very common congenital anomaly noted in children with reported incidence of 0.4-8.2% in 1000 live birth. Treatment of hypospadias is urethroplasty, but is a difficult procedure due to complex anatomy, nonavailability of adequate tissue for repair, prolonged postoperative course and increased incidence of complications even in experienced hands. Aim: To highlight the complications and functional outcome of various types of proximal hypospadias using standard surgical technique with intermediate vascularised flap. Materials and Methods: This was a retrospective cohort study conducted from on 31 children, between the age of 2-13 years from June 2020 to August 2020. The children had proximal hypospadias with or without chordee were operated using primary procedure Tubularised Incised Plate (TIP) and staged procedure with cover of intermediate vascularised flap. These children had peno-scrotal, proximal, mid and distal penile hypospadias with meatus placed 1.5 cm proximal from the glans tip. In all cases, an intermediate layer of vascularised flap was put to cover the neourethra. Tunica vaginalis flap was used in 27 cases and dartos flap in 4 cases. The outcomes of surgical procedure, early and late complications with follow-up results were analysed using descriptive statistics of frequency and percentage. Final functional results of the procedures and cosmesis were observed during a two-year follow-up period. Results: Out of the 31 patients, 27 patients had urethroplasty (20 staged procedures and seven TIP) with tunica vaginalis as intermediate layer. Another four patients had TIP urethroplasty with dartos as intermediate layer. Four patients of tunica vaginalis as intermediate layer had early urethrocutaneous fistula (14.8%), one patient (3.7%) required closure of fistula and another three closed spontaneously. Two patients had meatal stenosis (7.4%) and four had slight pulled up ipsilateral testis (14.8%). One patient of TIP urethroplasty with dartos as intermediate layer was reoperated for late urethrocutaneos fistula at corona glandis (25%). Conclusion: The outcome of pediatric urethroplasty was favourable with routine use of intermediate vascularised flap in proximal hypospadias repair. [ABSTRACT FROM AUTHOR]

An attempt was made to increase the solubility of High Level liquid Waste (HLW), mainly Cr and Mo, by addition of P2O5 to sodium borosilicate glass. A total of seven different phosphorus containing alkali borosilicate glass samples were in-house fabricated. As a part of chemical quality control, concentrations of four low Z elements namely Si, Na, B and P were determined by in situ current normalized external (in air) Particle Induced Gamma-ray Emission (PIGE) method using low energy proton beam from Folded Tandem Ion Accelerator (FOTIA), BARC. PIGE method was validated by analyzing synthetic elemental standards and suitable certified reference materials. Phosphorus has shown thermal losses during fabrication. [ABSTRACT FROM AUTHOR]

The limited ionic conductivity of polymer electrolytes is a major issue for their industrial application. Enhancement of ionic conductivity in the poly(ethylene oxide), PEO, based electrolyte has been achieved by loading passive nanofillers such as SiO2 nanoparticles (NPs). To investigate the role of modifications in free volume characteristics and the polymer chain dynamics induced by the loading of passive fillers on the ionic conductivity of the PEO based ternary electrolyte, a systematic investigation has been carried out using positron annihilation and broadband dielectric spectroscopy. As a result of interfacial interactions, the loading of SiO2 NPs alters the semi-crystalline morphology of PEO resulting in a higher crystallinity at lower loadings due to the surface confinement of PEO chains, and the formation of smaller PEO crystallites at higher loadings due to interparticle nanoconfinement. These modifications are accompanied by a decrease in free volume fraction at the lowest loading (0.5 wt%) followed by an increase at higher loadings (≥2.0 wt%). The Almond–West formalism considering two different universalities in different temperature and frequency ranges has been used to explain the ion-conduction process at different NP loadings. The Li ion conductivity is observed to be maximum for a 5.0 wt% loading of SiO2 NPs. The enhancement in ionic conductivity is observed to be directly correlated with the free volume characteristics and segmental dynamics of the PEO matrix, confirming their role in ion transport in polymer electrolytes. [ABSTRACT FROM AUTHOR]

An external (in air) Particle Induced Gamma-ray Emission (PIGE) method using tantalum (window material) as the external current normalizer was standardized for the first time for rapid compositional characterization of "as-received" sodalime (automobile) and borosilicate glass samples. It involves irradiation of glass fragments in air using a 3.5 MeV proton beam from the FOlded Tandem Ion Accelerator (FOTIA) and simultaneous measurement of prompt gamma-rays from proton induced reactions of isotopes of low Z elements (Si, Na, Al and/or Mg and B) and 135 or 165 keV from tantalum window (181Ta). The results of external PIGE were compared with those obtained by conventional (vacuum chamber) in situ current normalized PIGE by analyzing sample pellets in a cellulose matrix. External and conventional PIGE methods were validated by analyzing both sodalime and borosilicate glass certified reference materials. The external PIGE method is found to be a rapid non-destructive method for discriminating sodalime and borosilicate glasses both qualitatively and quantitatively through their composition, which is important for forensic applications. Among the major elements determined by external PIGE, aluminium was found to be the only marker element for distinguishing sodalime (automobile) glasses. In order to find more marker elements for a grouping study as well as for forensic applications of "as-received" sodalime/automobile glass samples, Instrumental Neutron Activation Analysis (INAA) using high reactor neutron flux (∼1013 n per cm2 per s) from the Dhruva research reactor was utilized for bulk analysis to quantify thirteen elements (Na, Mg, Al, Ca, Mn, Fe, Sc, Co, Hf, La, Ce, Sm and Eu) at major to trace concentration levels. Samples were irradiated utilizing the Pneumatic Carrier Facility (PCF) as well as the self-serve facility of Dhruva reactor for short duration irradiation followed by high resolution gamma-ray spectrometry to obtain the elemental concentrations of interest including transition elements and rare earth elements (REEs). Preliminary grouping of sodalime/automobile glasses was carried out using the concentrations of marker elements (Al, Sc, Fe, Co, Hf, La and Ce) and concentration ratios like Al/Sc, La/Sc and Ce/Sc and total REEs, and all results indicated that the glasses fall into three groups. The grouping was confirmed by statistical cluster analysis (i.e. tree dendrogram) utilizing concentrations of transition elements and REEs, which indicated the potential of elemental concentrations particularly at minor and trace concentration levels for forensic applications. [ABSTRACT FROM AUTHOR]

Defects evolved during thermal treatment in high Cr content Ni–Cr alloy have been studied using Positron lifetime and coincidence Doppler broadening spectroscopy complemented with microscopic technique. The single-phase gamma-quenched specimen obtained by solutionization at 1200 °C has been thermally aged at 650 °C and 800 °C. Thermal treatment resulted in the phase transformation of the matrix through precipitation of Cr. It is seen that solutionization treatment followed by quenching resulted in the stabilization of thermal vacancies generated at 1200 °C which effectively trap the positrons. The results infer that these vacancies may form vacancy-Cr complexes which act as nucleation site for Cr aggregation. Positron lifetime and momentum distribution of annihilation electrons indicated that in the aged alloys, positrons are trapped in vacancy-like defects (vacancy clusters/vacancy-solute complex) and the interface between Cr precipitate and matrix, the latter becoming more predominant with subsequent ageing. At the highest ageing studied, vacancy-like defects are evolved within the Cr precipitates. The results indicated that positron trapping sites (vacancies and precipitate interface) are not specific to either Ni or Cr atoms which surround the trapping site in nearly equal proportion. Therefore, unambiguous identification of the defect type at each stage of thermal treatment becomes difficult. Considering positron trapping at the surface of precipitates, we have calculated positron specific trapping coefficient to be ~ 1.33 × 10−6 cm3 s−1, which is of the order estimated for large voids and estimated the number density of precipitates. [ABSTRACT FROM AUTHOR]

An external particle induced gamma-ray emission (in air) PIGE facility has been set up for the first time at FOTIA, BARC for rapid and non-destructive quantification of low Z elements. Proton beam of energy of 3.5 MeV was obtained on the target using a 25 μm Tantalum window and Ta collimator of 5 mm diameter. The in situ current normalized PIGE method was validated by quantifying low Z elements in a mixed synthetic standard and in two (certified / standard) reference materials namely USGS CRM G2 and NIST SRM 620. The external PIGE method was applied to lithium-based ceramics, boron carbide and soda-lime and borosilicate glass samples for quantification of low Z elements. [ABSTRACT FROM AUTHOR]

A Prompt Gamma-ray Neutron Activation Analysis (PGNAA) facility was set up using a thermal neutron beam at Dhruva research reactor. It was utilized for non-destructive quantification of total boron in refractory neutron absorbers and 10B atom% in B4C ceramics having natural and enriched 10B composition by measuring the 478 keV prompt gamma-ray from 10B(n,αγ)*7Li. Self-shielding correction was carried out for higher boron concentration samples using chlorine as an internal standard. As a part of quality assurance, the results of PGNAA were compared with those obtained by in situ current normalized Particle Induced Gamma-ray Emission (PIGE) method. [ABSTRACT FROM AUTHOR]

Performance of 1″ × 1″ LaBr3 (5% Ce) scintillator coupled to Hamamatsu R2083 PM Tube has been investigated for the first time. Energy response and timing characteristics of the present assembly have been studied at different operating conditions for its application in fast timing spectroscopy. An energy resolution of 3.38 ± 0.03% at 662 keV γ-energy was obtained in the present work at a bias voltage of − 2800 V and a linear response could be observed up to a bias voltage of − 2500 V. Time resolution of a single LaBr3:Ce crystal was found to be 174 ± 2 ps and 121 ± 3 ps for 511–511 and 1173–1332 cascades respectively. Effect of applied bias voltage on the time resolution of the set up was studied and a steady improvement with increasing bias voltage was observed. Present results were compared with the previous results obtained with similar fast PM tubes and importance as well as implications of the present measurement were also discussed. [ABSTRACT FROM AUTHOR]

The in situ current normalized particle induced gamma-ray emission method using 4 MeV proton beam was utilized for total boron concentrations in boron based neutron absorbers and borated wood based neutron shielding materials. Boron carbide samples with varying masses were analyzed to examine the effect of matrix as well as the efficacy of the in situ current normalized method. Isotopic composition of boron (10B/11B atom ratio) has been determined in natural and 10B enriched boron carbide samples as well as in four synthetically prepared enriched boron carbide samples to serve as in-house reference standard for isotopic composition. [ABSTRACT FROM AUTHOR]

Nuclear analytical methods namely in situ current normalised Particle Induced Gamma Ray Emission (PIGE) and conventional Instrumental Neutron Activation Analysis (INAA) were utilized for determining major, minor and trace concentrations of eighteen elements in five soda-lime (automobile) glass samples. Concentration of four major elements (Si, Na, Mg and Al) by PIGE and fourteen elements including ten trace elements by INAA were determined. For forensic application, major elements were used for confirming the class of glass samples, whereas concentration results of trace elements like transition and rare earth elements were utilized for finding similarity or differences among the glass samples. [ABSTRACT FROM AUTHOR]

A highly efficient and environmentally benign protocol is described for the microwave-assisted one-pot synthesis of aromatic nitriles from aromatic aldehydes by the reaction with hydroxylamine hydrochloride in DMSO, which involves the intermediate formation of aldoximes and subsequent dehydration. The developed synthetic methodology can be readily accomplished with various aldehydes containing both electron-donor and electron-acceptor groups, providing excellent yields of the target products in shorter reaction times (1–2 min) compared to previously reported methodologies. [ABSTRACT FROM AUTHOR]

The low temperature behavior of water and kinetics of ice nucleation in titania mesopores have been probed by positron annihilation lifetime spectroscopy as a function of pore filling. It is revealed that water undergoes complete freezing at around 220 K when more than 50% of the pore volume is filled and such freezing is hindered at lower hydration levels. A model describing progressive trapping of positronium by ice nuclei in liquid water during the phase transition is employed to estimate the energy associated with the nucleation under confinement. It is observed that the energy for ice nucleation in confinement is less than the activation energy for nucleation in bulk water because of the surface assisted nucleation inside the pore. Interestingly, energy for nucleation is seen to decrease with the lowering of hydration level and ascribed to the curtailed hydrogen bonding network of water at lower pore filling. [ABSTRACT FROM AUTHOR]

The present work reports the microscopic details of anatase (A) to rutile (R) phase transformation in a Mn-doped TiO2 system. Titanium dioxide (TiO2) powder was synthesized at three different dopant percentages, namely 1, 5, and 10 atom% of Mn, by a coprecipitation technique. Time differential perturbed angular correlation (TDPAC) spectroscopy was used to identify the formation of the rutile-like phase (R*) during the phase-transition process and revealed interface nucleation to be promoted by the Mn dopant. Electron paramagnetic resonance (EPR) spectroscopy, synchrotron-based X-ray absorption near edge structure (XANES), and extended X-ray absorption fine structure (EXAFS) studies showed that Mn exhibited a mixed valence states of 2+ and 4+ at different stages of the annealing process. The rutile onset temperature gradually decreased with the increase in the Mn content. The present report proposes the mechanism for the phase transformation and details the effect of Mn on the A to R phase-transformation process. This can assist in gaining a fundamental understanding of the A to R phase-transformation process and the role of the dopant in stabilizing one phase over the other. [ABSTRACT FROM AUTHOR]

The article gives the summary of our R&D contributions of in situ current normalized particle induced gamma-ray emission (PIGE) method utilizing proton beams from accelerators to quantify low Z elements from Li to Ti in various samples. Measurement of prompt gamma-rays from proton induced reactions was performed by HPGe detector system coupled to MCA. PIGE methods were utilized for non-destructive quantification of low Z elements in glass, ceramics like lithium titanate, Li-ion batteries and archaeological artifacts, environmental and food samples, and simultaneous quantification of total B and its isotopic composition in boron-based neutron absorbers, alloys and refractory materials. [ABSTRACT FROM AUTHOR]

Carotid Artery Injury is a life-threatening emergency. Injuries to the Carotid Artery constitute a particularly challenging subset of arterial trauma because they have the potential to produce exsanguinating hemorrhage, suffocating airway compromise and debilitating cerebral damage. The majority of patients with vascular neck injuries died at the site where the injury occurred or during transport to medical facilities. Transection of the Common Carotid Artery is very rarely encountered and most surgeons lack experience for intervention of the same. We reported a case of carotid artery injury, who presented to us in shock. Aggressive resuscitation and timely surgical intervention saved the life. [ABSTRACT FROM AUTHOR]

Boron based refractory materials such as boron carbide (natural and enriched), titanium based boron composites and borides of Zr, La and Ce are important neutron absorber materials for nuclear power reactors as control/shut-off rod and/or shielding materials. As a part of chemical quality control (CQC), it is essential to ascertain the mass fraction of boron as well as its isotopic composition (IC) in these materials by a suitable analytical method. In the present work, these materials have been analysed by Particle Induced Gamma-ray Emission (PIGE) using a 4 MeV proton beam from the Folded Tandem Ion Accelerator (FOTIA) at BARC, Mumbai, for simultaneous determination of the IC (10B/11B atom ratio) and total boron mass fraction determination. For total boron mass fraction determination an in situ current normalized PIGE method was used, with fluorine as the current normalizer. As a part of quality assurance, the IC of boron was determined by Thermal Ionization Mass Spectrometry (TIMS) and the total boron mass fraction was determined by a conventional titrimetry method. The results obtained by the PIGE method, its advantages and a comparison of the results obtained using the two conventional analytical methods are discussed in this paper. [ABSTRACT FROM AUTHOR]

Confinement of polymer chains in polymer nanocomposites influences their dynamics leading to the changes in their molecular packing compared to pure polymer. In order to study the exclusive effects of confinement on molecular packing of polyvinyl alcohol (PVA) chains, PVA nanocomposite films with varying (wt%) gold nanoparticles (Au NPs) were prepared using simple solution casting method. The triplet state of positronium (ortho‐positronium, o‐Ps) was used as a probe for determination of sub nano level free volume holes’ size, density, and size distribution. The study shows that molecular packing (free volume characteristics) is exclusively modified due to the confinement of PVA chains though there is no direct interfacial interaction between PVA and Au NPs. The changes are suppressed at highest studied Au NPs loading (0.60 wt%) mainly due to nanoparticle aggregation leading to an increase in the inter particle distance, a parameter which quantitatively defines the effect of confinement in polymer nanocomposites. X‐ray diffraction (XRD) and Fourier transformed infra‐red (FTIR) measurements were carried out to index the crystallinity and hydrogen bonding of PVA matrix. The variation in thermo‐mechanical properties (Young's modulus and glass transition temperature) of the nanocomposite is explained considering the changes in molecular packing and crystallinity of PVA matrix. POLYM. COMPOS., 39:1137–1143, 2018. © 2016 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Cross sections of reaction products were measured in SiNb reaction using recoil catcher technique involving by off-line gamma-ray spectrometry at beam energies of 105 and 155MeV. At MeV, the contribution from different incomplete mass transfer processes is investigated. Results of the present studies show the contribution from deep inelastic collision (DIC), massive transfer or incomplete fusion (ICF) and quasi-elastic transfer (QET). The contribution from massive transfer reactions was confirmed from the fractional yield of the reaction products in the forward catcher foil. The present results are different from those from the reactions with comparatively higher entrance channel mass asymmetry with lighter projectiles, for which dominant transfer processes are ICF and QET which involve mass transfer predominantly from projectile to target. The values of the products close to the target mass were observed to be in a wide range, starting from of the target (Nb) and extending slightly below the of the composite system, consistent with the contribution from DIC and QET reactions. At MeV, a small contribution from QET was observed in addition to complete fusion. [ABSTRACT FROM AUTHOR]

Lithium titanate and lithium aluminate, proposed as tritium breeding blanket materials in D-T fusion reactor, were analyzed by nuclear analytical techniques as a part of chemical quality control exercise. Concentrations of Li, Ti and Al were quantified by particle induced gamma-ray emission using 4 MeV proton beam from folded tandem ion accelerator facility. Trace elemental concentrations belonging to long-lived nuclides were determined by instrumental neutron activation analysis using neutron flux from Dhruva research reactor at BARC. The analysis results are useful in designing a shielded facility for tritium release studies of these irradiated breeder materials. [ABSTRACT FROM AUTHOR]

Particle induced gamma-ray emission (PIGE) method using 4 MeV proton beam was utilized to analyze two types of barium borosilicate glass (BaBSG) samples for quantification of concentrations of low Z elements. The in situ current normalization method was applied in the analysis of eight samples containing varying concentration of F along with Si, B and Na. Charge normalized PIGE method was applied to determine concentrations of above low Z elements including Li and Al in samples having simulated nuclear waste from reprocessing of thoria spent fuel. Synthetic samples and NIST SRMs were used for method validation. [ABSTRACT FROM AUTHOR]

MgO particles of few micron size are synthesized through a sol–gel method at different annealing temperatures such as 600 °C (MgO-600), 800 °C (MgO-800) and 1000 °C (MgO-1000). EDX and ICP-AES studies confirmed a near total purity of the sample with respect to paramagnetic metal ion impurities. Magnetic measurements showed a low temperature weak ferromagnetic ordering with a TC (Curie temperature) around 65 K (±5 K). Unexpectedly, the saturation magnetization (Ms) was found to be increased with increasing annealing temperature during synthesis. It was observed that with J = 1 or 3/2 or S = 1 or 3/2, the experimental points are fitted well with the Brillouin function of weak ferromagnetic ordering. A positron annihilation lifetime measurement study indicated the presence of a divacancy (2VMg + 2VO) cluster in the case of the low temperature annealed compound, which underwent dissociations into isolated monovacancies of Mg and O at higher annealing temperatures. An EPR study showed that both singly charged Mg vacancies UGRAPHIC DISPLAY="INLINE" ID="UGT1" SRC="UGT1"/ and oxygen vacancies UGRAPHIC DISPLAY="INLINE" ID="UGT2" SRC="UGT2"/ are responsible for ferromagnetic ordering. It also showed that at lower annealing temperatures the contribution from UGRAPHIC DISPLAY="INLINE" ID="UGT3" SRC="UGT3"/ was very low while at higher annealing temperatures, it increased significantly. A PL study showed that most of the F+ centers were present in their dimer form, i.e. as UGRAPHIC DISPLAY="INLINE" ID="UGT4" SRC="UGT4"/ centers. DFT calculation implied that this dimer form has a higher magnetic moment than the monomer. After a careful consideration of all these observations, which have been reported for the first time, this thermally tunable unusual magnetism phenomenon was attributed to a transformation mechanism of one kind of cluster vacancy to another. [ABSTRACT FROM AUTHOR]

Particle induced gamma-ray emission method was used to quantify total fluorine (F) concentrations in soil and food samples obtained from fluoride affected as well as non-affected areas of Punjab state, India. Samples, standards and reference materials in pellet form with lithium as in situ current normalizer were irradiated using 4 MeV proton beam from the tandem particle accelerator. Characteristic prompt gamma rays at 197 keV from F and 478 keV from Li were measured using a HPGe detector system. Fluorine concentrations in soil and food samples were 279-3138 and 51-211 mg kg, respectively. [ABSTRACT FROM AUTHOR]

A microscopic model of the interfacial region is required to improve understanding of the role of local structure in bulk physical properties in metal organic framework-based polymer nanocomposites. A zeolitic imidazolate framework (ZIF-8)-based (loading 2–30 wt%) composite of poly vinyl alcohol (PVA) is studied as a model system to investigate the role of interfacial interaction in molecular packing, glass transition process and tensile properties. Attractive interfacial interaction between the surface of ZIF particles and PVA chains is established by Fourier transform infra red (FTIR) measurements. The morphology of the nanocomposites is characterized using X-ray diffraction and scanning electron microscopy (SEM), showing that aggregation of particles started from 5 wt% of ZIF-8. At low loadings, occurrence of two glass transitions measured using differential scanning calorimetry indicates two spatial zones, viz. interphase and bulk layers, of different packing density in the PVA matrix. With increase in loading, molecular packing throughout the polymer matrix is changed as the interparticle distance and interphase width become comparable. At the highest loading, PVA shows bulk glass transition temperature because of the non-significant volume fraction of interphase resulting from aggregation of ZIF. Molecular packing (free volume structure) of PVA in the nanocomposites is investigated using ortho-positronium lifetime distributions, which show that large vacant spaces are created at the interfacial region leading to a low-density interphase. The existence of a low-density interphase is also supported by bulk-density measurements of the nanocomposites. Tensile testing measurements show a decrease in ductility of the nanocomposites, indicating enhancement in rigidity of polymer chains at the interfacial region because of attractive interfacial interaction. This study indicates that the polymer chain framework at the interfacial region in PVA–MOF nanocomposites can be represented by a rigid but rather open network. [ABSTRACT FROM AUTHOR]

This article focuses on the calculation of transport parameters (number density of ions and time travel of ions between sites, mobility, diffusion coefficient, and number of transitions per unit time) of the lithium perchlorate (LiClO4)-doped poly(vinyl alcohol)/chitosan (PVA/CS) composites using Rice and Roth model. The thermal study reveals a decrease in glass transition temperature for LiClO4-doped PVA/CS composites. The highest ionic conductivity of 3 × 10−6 S cm−1 at room temperature is observed for the 20 wt% LiClO4-containing composite. The temperature-dependent conductivity follows Arrhenius relation and lowest activation energy of 0.153 eV is observed for highest conducting sample. The mechanical properties such as Young’s modulus, stiffness, and tensile strength decreases and its percentage elongation at break increases with increase in LiClO4-doping level in PVA/CS polymer matrix. The scanning electron microscopic images exhibit smooth and homogeneous surface of PVA/CS composite. [ABSTRACT FROM AUTHOR]

Pure and Eu3+ doped β-Ag2MoO4 were synthesized using a co-precipitation method at room temperature. The as prepared compounds were characterized systematically using X-ray diffraction (XRD), photoluminescence (PL) spectroscopy, cyclic voltammetry (CV) and positron annihilation lifetime spectroscopy (PALS). It is observed that pure β-Ag2MoO4 gives blue (445 nm) and green (550 nm) emission when irradiated with UV light. The origin of the green band was qualitatively explained from density functional theory (DFT) calculations using a suitable distortion model. It was observed that on doping europium ions, efficient energy transfer from molybdate to europium takes place. The excitation spectrum depicting f–f transitions (particularly 395 nm and 465 nm peaks) is much more intense than the CTB showing that Eu3+ ions can be effectively excited by near UV-light. Based on DFT calculations it is proposed that due to the occurrence of Eu3+ d-states in the conduction band (CB) as well as the strong contribution of Eu3+ d-states to the impurity level present in the vicinity of the Fermi level, the host (β-Ag2MoO4) to dopant (Eu3+) energy transfer is preferable. β-Ag2MoO4 is also explored as a potential candidate for electrocatalysis of the oxygen reduction reaction (ORR). It was observed that the doping of europium ions in β-Ag2MoO4 enhances the electrocatalytic activity toward the ORR. The presence of a large concentration of cation vacancies and large surface defects as suggested by positron annihilation lifetime spectroscopy (PALS) seem to be aiding the ORR. [ABSTRACT FROM AUTHOR]

Poly(vinyl alcohol), PVA, reinforced with carbon nanofillers has shown drastic variations in thermal as well as mechanical properties. In order to establish structure–property correlations, these variations have been correlated with modifications in the hydrogen bonding structure as well as the crystallinity of the PVA matrix without paying much attention to molecular packing in the amorphous region of this semicrystalline polymer. In order to investigate the molecular packing in PVA–graphene oxide (GO) nanocomposites, free volume characterization of PVA–GO nanocomposites has been carried out using ortho-positronium (o-Ps) probe. The variations in free volume size, density and size distribution have been determined through o-Ps lifetime and the corresponding intensity as well as its lifetime distribution. The variation in hydrogen bonding and its effect on crystallinity has been determined by Fourier Transform Infra Red (FTIR) and X-ray diffraction (XRD) measurements. The variation in the thermal (glass transition temperature) and mechanical (Young's modulus, tensile strength and percentage strain at break) properties of the nanocomposites is explained in view of the free volume structure and crystallinity of the PVA matrix which are severely modified due to the molecular-level dispersion of GO sheets in the PVA matrix. [ABSTRACT FROM AUTHOR]

This paper presents the investigation on physicochemical properties and ionic conductivity of LiClO-doped poly(vinyl alcohol) (PVA)/modified cellulose composites. The percolative behaviour of LiClO with dc conductivity ( σ) for different LiClO weight fractions ( p) related to transport dimensionality was also focused. The highest ionic conductivity of 9.79 × 10 S cm was observed for 20 wt% LiClO doping level at room temperature. The activation energies ( E) were estimated using temperature-dependent conductivity, which follows the Arrhenius and Vogel-Tammann-Fulcher (VTF) relation. The dynamic fragility ( f) and activation energy ( E) vs. T of polymer composites using equivalence of the both Williams-Landel-Ferry (WLF) and VTF equations were also correlated. Transport properties such as travel time of ions between sites ( τ), mobility ( μ), diffusion coefficient ( D) and number of transitions per unit time P( E) for normal cationic (Li) hopping process of LiClO-doped PVA/mCellulose composites have been investigated using the Rice and Roth model. [ABSTRACT FROM AUTHOR]

Lithium titanate is a proposed tritium breeding blanket material in D-T based fusion reactor under International Thermonuclear Experimental Reactor programme. For optimization of sol-gel preparation method and chemical quality control, compositional characterization of LiTiO was carried out by particle induced gamma-ray emission using 8 MeV proton beam at BARC-TIFR pelletron facility. For the first time, a non-destructive method has been standardized for simultaneous determination of Li, Ti and O in this ceramic sample, which is otherwise difficult by various wet-chemical as well as radio-analytical methods. Thick targets of samples, synthetic samples and standards prepared in graphite matrix were used for the experiment. Rutherford backscattering spectrometry method was used for beam current monitoring using a thin Au foil. The gamma-rays at 478, 983 and 6129 keV from Li(p, p′γ)Li, Ti(p, p′γ)Ti and O(p, p′γ)O nuclear reactions, respectively, were measured using high resolution gamma-ray spectrometry and corresponding peak areas were used for concentration calculations by relative method. [ABSTRACT FROM AUTHOR]

Boron is an important element in nuclear technology. A comparative study was carried out for the determination of boron in borosilicate glass, boron carbide and graphite samples by wet-chemical and nuclear analytical methods. Wet chemical methods namely titrimetry, Inductively Coupled Plasma Mass Spectrometry and ICP Optical Emission Spectrometry and nuclear analytical methods namely Particle Induced Gamma-Ray Emission and Nuclear Reaction Analysis were used. Boron concentrations were in trace (mg kg) level in graphite and percentage level in borosilicate glass and boron carbide. [ABSTRACT FROM AUTHOR]

A digital gamma-ray spectrometer with loss-free counting system was used for real time correction for dead time (DT) due to pulse processing in the electronics. This spectrometer was used for radioactive assay of samples having constant as well as varying DT conditions. The system was tested by measuring activity of short and medium lived nuclides namely Al, V and I in the DT ranges of 80-2 %. Using this spectrometer and neutron activation analysis (NAA), concentrations of Al, V, Ti, Ca, Dy and Mn were determined in some samples and reference materials. [ABSTRACT FROM AUTHOR]

Food and food products are the main sources of Aluminium entering the human body. In order to know aluminium contents in food and food products, selected 26 samples from local market were analyzed by instrumental neutron activation analysis (INAA) using reactor neutrons and high resolution gamma-ray spectrometry. INAA using 1,779 keV γ-ray of Al (2.24 min) was used for aluminium concentrations in the range of 33-529 mg kg. Two NIST standard reference materials (SRMs) and two IAEA reference materials (RMs) were analyzed by INAA for quantification of aluminium as a part of method validation. [ABSTRACT FROM AUTHOR]

The pneumatic carrier facility (PCF) of Dhruva reactor is being extensively used for neutron activation analysis (NAA) studies pertaining to research work as well as routine sample analysis. It is useful for the determination of trace elements using short and medium half-lives radioisotopes produced in neutron activation with available higher neutron flux (~5 × 10 cm s). Solid samples placed in high density polypropylene capsule, are irradiated for 1 min duration and radioactive assay is carried out by high resolution gamma ray spectrometry. Design aspects of PCF and various applications to samples of diverse matrices using NAA are presented. [ABSTRACT FROM AUTHOR]

A non-destructive, in situ current normalized particle induced gamma-ray emission methodology has been standardized for quantification of fluorine (F) in soil samples from Punjab state, India. The samples were irradiated using 4 MeV proton beam from the Folded Tandem Ion Accelerator at BARC, Mumbai. The gamma rays of energies 197 and 478 keV arising from F(p, p′γ)F and Li(p, p′γ)Li nuclear reactions were measured using high resolution gamma-ray spectrometry. The concentration of fluorine in soil samples was found to vary between 414 and 5,746 mg kg. [ABSTRACT FROM AUTHOR]