Search results for "bulk"

Zinc-blende AlN and GaN under pressure: structural, electronic, elastic and piezoelectric properties

2004

In this paper we report a theoretical study of the structural, elastic, electronic and piezoelectric properties of zinc-blende AlN and GaN under the pressure effect. The study is focused on the first-principles all electron full-potential augmented plane wave plus local orbitals calculations within the density-functional theory. The results of bulk properties, including lattice constants, bulk modulus and derivatives and band structures are obtained and compared using both the local density approximation (LDA) and the generalized gradient approximation (GGA) for the exchange-correlation functional. We find that the GGA does not give a significant improvement over LDA. We also report calcula…

Effect of carbon source supply and its location on competition between inoculated and established bacterial strains in sterile soil microcosm

1999

The aim of this work was to study how the location of a carbon source and of bacterial cells in soil can enhance the growth of a bacterial inoculum. Studies were performed using irradiated soil and two pairs of strains of Bradyrhizobium japonicum and Pseudomonas fluorescens. For each species, an antibiotic-resistant mutant was used as inoculant and introduced into a sterile soil pre-colonised with its parent strain. The inocula and a glycerol amendment were introduced together or separately into soil using porous microgranules or by spraying a suspension onto the bulk soil. Competition was assessed by plate counts of both inoculant and established populations. Both B. japonicum and P. fluor…

Quantitative identification, distribution and source apportionment of anthropogenic trace metals in marine sediment of Milazzo gulf (N-E Sicily): pre…

2009

Influence of Intraperitoneal Dissemination Assessed by Laparoscopy on Prognosis of Advanced Ovarian Cancer: An Exploratory Analysis of a Single-Insti…

2014

Purpose: The aim of this study was to investigate whether preoperative laparoscopic evaluation of the dissemination of disease may have an independent impact on survival in advanced epithelial ovarian cancer (AEOC).Methods: All AEOC women were submitted to staging laparoscopy before receiving primary debulking surgery (PDS) or neoadjuvant chemotherapy (NACT). All study women received a laparoscopic score (predictive index value [PIV]) and were stratified into three groups based on volume of disease: high tumor load (HTL) for PIV ≥8, intermediate tumor load (ITL) for PIV equal to 6 and 4, and low tumor load (LTL) for PIV 1 cm in 15 cases (9.1 %). When stratifying the whole population accordi…

Pressure-induced chemical decomposition of copper orthovanadate (α-Cu3V2O8)

2021

The high pressure stability of α-Cu3V2O8 has been investigated via complementary high pressure synchrotron X-ray diffraction experiments and theoretical density functional theory calculations. The results of both experiment and theory are in close agreement. The main result of this work is that α-Cu3V2O8 undergoes a pressure-induced chemical decomposition into CuO and V2O5 at a modest pressure of ∼1.35 GPa according to the experimental observations, and at ∼2.45 GPa according to the calculations. The decomposition is investigated with enthalpy calculations and one of the main driving factors is the stability of the octhedral oxygen-coordination of the metal atoms in the decompositon product…

Ab initio Calculations of Bulk and (001) Surface F-centers in ABO3 Perovskites

2021

We analyzed systematic trends in BaTiO 3, SrTiO 3 , PbZrO 3 and SrZrO 3 bulk as well as very rarely performed (001) surface F-center ab initio calculations. The nearest neighbor atomic displacements around the bulk F-center in the ABO 3 perovskites are considerably smaller than the relevant neighbor atomic displacements around the (001) surface $F$ -centers. The $F$ -center electrons are more delocalized for the ABO 3 perovskite (001) surface $F$ -center than for the bulk $F$ -center. Our calculated formation energy differences between the BaTiO 3 , SrTiO 3 , PbZrO 3 and SrZrO 3 bulk and its (001) surface $F$ -centers triggers the $F$ -center segregation from the bulk crystal towards the AB…

Photoimaging through in-Situ Photopolymerization of Heterobifunctional Mesogenic Compounds in Liquid Crystalline State

2007

A series of heterobifunctional mesogenic biphenyl esters having two different polymerizable groups, i.e., acryl and diacetylene groups, were synthesized and their thermal behaviors and polymerization investigated. All compounds showed enantiotropic transitions. Under POM, highly birefringent focal-conic fan textures appeared on heating and cooling from the isotropic melt. Compounds 6−8 having a butyl spacer between a biphenyl and a diacetylene group exhibited LC phases even at room temperature. The X-ray diffractograms of compounds 6−8 showed a set of reflections in the small-angle region. They consisted of more than three sharp diffraction peaks with d spacings in the ratio of 1:1/2:1/3, s…

Effect of over the counter mouthwashes with and without alcohol on sorption and solubility of bulk fill resins

2020

Background Composites sorption and solubility can be precursors of several chemical and physical processes, which lead to deleterious effects on the polymer structure. This study evaluated the effect of mouthwashes with and without alcohol on the sorption and solubility of conventional and low viscosity bulk fill resins. Material and Methods Four types of Bulk Fill resins (Filtek™ Bulk Fill, X-tra Fil, Filtek™ Bulk Fill Flow and X-tra Base) were submitted to the following mouthwashes: Listerine Cool Mint and Periogard (containing alcohol) and Listerine Zero and Periogard (alcohol-free). The specimens were stored in the mouthwashes for seven days. Solubility and sorption tests were performed…

Soil Erosion Induced by the Introduction of New Pasture Species in a Faxinal Farm of Southern Brazil

2018

The faxinal management system is an endangered agro-silvopastoral system which forms part of the local traditional management in the Paraná federal state (Brazil). Significant changes in land management since the 1970s caused farmers to look for alternatives to increase the productivity of their farms. The introduction of new pasture species is causing land degradation problems, of which soil erosion is the most important challenge. Therefore, in this study, we assessed the environmental consequences of introducing exotic pasture species, such as Brachiaria decumbens. To achieve this goal, ten erosion plots were installed with exotic and native pastures (Paspalum notatum Flügg&e…

Electrochemical incineration of 1,2-dichloroethane: Effect of the electrode material

2008

The electrochemical incineration of 1,2-dichloroethane (EDC) at Pt, Au, boron-doped diamond (BDD), Ebonex, stainless steel, Ti/IrO2–Ta2O5 and PbO2 has been studied in acid media by cyclic voltammetry and bulk electrolysis. It has been shown that the performances of the process dramatically depend on the anodic material. Higher current efficiencies were obtained at BDD. In particular, at proper values of applied current density, it is possible to obtain the almost complete conversion of EDC to CO2 at BDD with current efficiencies higher than 40%.