In situ carbon coated Li2MnSiO4/C composites as cathodes for enhanced performance li-ion batteries

An in-situ carbon coated Li2MnSiO4/C composite was synthesized by a nanocomposite gel precursor route using starch as the carbon source. Our approach enabled a uniform coating of amorphous carbon on Li 2MnSiO4 with an orthorhombic crystalline structure, which was confirmed by electron microscopy, X-ray diffraction and Raman studies. Conducting-atomic force microscopy (C-AFM) images also revealed the presence of high current interconnected domains in the composite, indicating the ability of the carbon coating to facilitate electron movement. Galvanostatic charge-discharge studies demonstrated outstanding initial charge and discharge capacities, respectively, of 330 and 195 mAh g-1 at 0.05 C-rate for the composite, and after 30 cycles a reversible capacity of 115 mAh g -1 was retained. The electrochemical performance of the neat silicate was dismal (10.6 mAh g-1 at 0.05 C-rate), which again reiterated the role of carbon in improving the conduction and Li-ion storage capacity of the silicate. An insignificant change in charge transfer resistance, with cycling, as inferred from impedance spectroscopy illustrated that charge transfer and transport processes remain facile with cycling, thus demonstrating Li 2MnSiO4/C to be promising cathode Li-ion batteries

Evaluation of the Anxiolytic Activity of NR-ANX-C (a Polyherbal Formulation) in Ethanol Withdrawal-Induced Anxiety Behavior in Rats

The present study investigates the anxiolytic activity of NR-ANX-C, a standardized polyherbal formulation containing the extracts of Withania somnifera, Ocimum sanctum, Camellia sinensis, Triphala, and Shilajit in ethanol withdrawal- (EW-) induced anxiety behavior in rats. Ethanol dependence in rats was produced by substitution of drinking water with 7.5% v/v alcohol for 10 days. Then, ethanol withdrawal was induced by replacing alcohol with drinking water, 12 hours prior to experimentation. After confirming induction of withdrawal symptoms in the alcohol deprived animals, the anxiolytic activity of the test compound in graded doses (10, 20, and 40 mg/kg) was compared to the standard drug alprazolam (0.08 mg/kg) in the elevated plus maze and bright and dark arena paradigms. In our study, single and repeated dose administration of NR-ANX-C reduced EW-induced anxiety in a dose-dependent manner. Even though the anxiolytic activity was not significant at lower doses, NR-ANX-C at the highest dose tested (40 mg/kg) produced significant anxiolytic activity that was comparable to the standard drug alprazolam. Based on our findings we believe that NR-ANX-C has the potential to be used as an alternative to benzodiazepines in the treatment of EW-induced anxiety

Objective structured practical examination (OSPE) as a tool in formative assessment of II MBBS students, in pathology

Background: Assessment drives the student learning. Regular periodical assessment not only improves learning habits, but also enhances the competence in all levels of medical education. Traditional practical examination is more subjective. It depends on examiners subjectivity, varying difficulty level of various experiments, and also internal marks variation etc. These flaws can be overcome by newer methods like OSPE. The aim of the study was to implement OSPE as a tool of internal assessment for practical skills in the II MBBS. To compare this with traditional practical examination (TPE). To obtain the students and faculty feedback regarding OSPE as a tool of assessment.Methods: A cross sectional study was carried out for 158 students in II internal pathology practical examination for six days in the second week of September 2016 at Department of Pathology, Dr. Pinnamaneni Siddhartha institute of medical sciences & Research Foundation, Chinnaoutpalli. Faculty and students were sensitized; blueprint were used to arrange twenty OSPE stations for the exercises conducted as per TPE and for the same 25 marks as per TPE. Simultaneously, all the students were subjected to both TPE and OSPE at the same time and venue. TPE was assessed by two professors and OSPE by separate eight faculty members independently without interaction with the students. The procedural stations were evaluated by using checklist and the response stations which consisted of short answers and MCQs, facilitated correction. Feedback was given to the student on their performance and feedback was obtained from the students and faculty regarding OSPE by questionnaire with Yes/No answers.Results: Performance score of students in OPSE (13.73 ±2.49) was higher as compared to TPE (9.27±1.86) which was statistically significant. Based on the response to the questionnaire, students perception towards OSPE was analyzed. Majority strongly agree OSPE to be fairer, more transparent and objective in comparison to TPE. In contrast, all the faculty members unanimously opined that OSPE was difficult to arrange, time taken and faculty versus students ratio was high for evaluation. Though, the faculty (91%) overall opined that OSPE should be included as a method of assessment.Conclusions: Present study revealed that OSPE was acceptable, feasible and reliable to the students as well as for faculty for the internal assessment in pathology. Opinions of both students and faculties strongly agreed that OPSE is more effective objective assessment tool

Coupled Phonons, Magnetic Excitations and Ferroelectricity in AlFeO3: Raman and First-principles Studies

We determine the nature of coupled phonons and magnetic excitations in AlFeO3 using inelastic light scattering from 5 K to 315 K covering a spectral range from 100-2200 cm-1 and complementary first-principles density functional theory-based calculations. A strong spin-phonon coupling and magnetic ordering induced phonon renormalization are evident in (a) anomalous temperature dependence of many modes with frequencies below 850 cm-1, particularly near the magnetic transition temperature Tc ~ 250 K, (b) distinct changes in band positions of high frequency Raman bands between 1100-1800 cm-1, in particular a broad mode near 1250 cm-1 appears only below Tc attributed to the two-magnon Raman scattering. We also observe weak anomalies in the mode frequencies at ~ 100 K, due to a magnetically driven ferroelectric phase transition. Understanding of these experimental observations has been possible on the basis of first-principles calculations of phonons spectrum and their coupling with spins

An indigenous cluster beam apparatus with a reflectron time-of-flight mass spectrometer

The design and fabrication of a Smalley-type cluster source in combination with a reflectron based time-of-flight (TOF) mass spectrometer are reported. The generation of clusters is based on supersonic jet expansion of the sampling plume. Sample cells for both liquid and solid targets developed for this purpose are described. Two pulsed Nd-YAG lasers are used in tandem, one (532 nm) for target vapourization and the other (355 nm) for cluster ionization. Methanol clusters of nuclearity up to 14 (mass 500 amu) were produced from liquid methanol as the test sample. The clusters were detected with a mass resolution of ~2500 in the R-TOF geometry. Carbon clusters up to a nuclearity of 28 were obtained using a polyimide target. The utility of the instrument is demonstrated by carrying out experiments to generate mixed clusters from alcohol mixtures

Solvent Extraction Studies of Gadolinium in Tri-Butyl Phosphate

AbstractFast reactor spent fuel reprocessing plants should be designed for inherent criticality safety due to high plutonium content. Addition of soluble neutron poison is one way to do that. Gadolinium is the best choice based on neutron absorption cross section and chemical compatibility. In this work, using classical thermodynamic approach, the distribution coefficient of gadolinium in tributyl phosphate has been calculated and compared with the experimental data. The influence of acidity and uranium at equilibrium on gadolinium distribution in tributyl phosphate has been investigated. The result establishes the feasibility of employing gadolinium as soluble neutron poison in fast fuel reprocessing

Enhanced nanoscale conduction capability of a MoO 2/Graphene composite for high performance anodes in lithium ion batteries

A MoO 2/Graphene composite as a high performance anode for Li ion batteries is synthesized by a one pot in-situ low temperature solution phase reduction method. Electron microscopy and Raman spectroscopy results confirm that 2D graphene layers entrap MoO 2 nanoparticles homogeneously in the composite. X-ray photoelectron spectroscopy shows the presence of oxygen functionalities on graphene, which allows intimate contact between MoO 2 nanoparticles and the graphene. Conductive atomic force microscopy reveals an extraordinarily high nanoscale electronic conductivity for MoO 2/Graphene, greater by 8 orders of magnitude in comparison to bulk MoO 2. The layered nanostructure and the conductive matrix provide uninhibited conducting pathways for fast charge transfer and transport between the oxide nanoparticles and graphene which are responsible for the high rate capability, a large lithium ion capacity of 770 mAh g -1, and an excellent cycling stability (550 mAh g -1 reversible capacity retained even after 1000 cycles!) at a current density of 540 mA g -1, thereby rendering it to be superior to previously reported values for neat MoO 2 or MoO 2/Graphene composite. Impedance analyses demonstrate a lowered interfacial resistance for the composite in comparison to neat MoO 2. Our results demonstrate the enormous promise that MoO 2/Graphene holds for practical Li-ion batterie

IR MPD CDF<SUB>3</SUB> in two-frequency IR fields

The effectiveness of various sets of laser frequencies was analyzed for two-frequency MPD of CDF3 molecule at the different pressures of buffer gas. It was shown that MPD yield increased compared to either single-frequency or two adjacent frequencies irradiation

Transition Phenomena Induced by Internal Noise and Quasi-absorbing State

We study a simple chemical reaction system and effects of the internal noise. The chemical reaction system causes the same transition phenomenon discussed by Togashi and Kaneko [Phys. Rev. Lett. 86 (2001) 2459; J. Phys. Soc. Jpn. 72 (2003) 62]. By using the simpler model than Togashi-Kaneko's one, we discuss the transition phenomenon by means of a random walk model and an effective model. The discussion makes it clear that quasi-absorbing states, which are produced by the change of the strength of the internal noise, play an important role in the transition phenomenon. Stabilizing the quasi-absorbing states causes bifurcation of the peaks in the stationary probability distribution discontinuously.Comment: 6 pages, 5 figure

Theoretical Analysis of the "Double-q" Magnetic Structure of CeAl2

A model involving competing short-range isotropic Heisenberg interactions is developed to explain the "double-q" magnetic structure of CeAl$_2$. For suitably chosen interactions, terms in the Landau expansion quadratic in the order parameters explain the condensation of incommensurate order at wavevectors in the star of (1/2 $-\delta$, 1/2 $+\delta$, 1/2)$(2\pi/a)$, where $a$ is the cubic lattice constant. We show that the fourth order terms in the Landau expansion lead to the formation of the so-called "double-q" magnetic structure in which long-range order develops simultaneously at two symmetry-related wavevectors, in striking agreement with the magnetic structure determinations. Based on the value of the ordering temperature and of the Curie-Weiss $\Theta$ of the susceptibility, we estimate that the nearest neighbor interaction $K_0$ is ferromagnetic, with $K_0/k=-11\pm 1$K and the next-nearest neighbor interaction $J$ is antiferromagnetic with $J/k=6 \pm 1$K. We also briefly comment on the analogous phenomenon seen in the similar system TmS.Comment: 22 pages, 6 figure