Chemical Desensitization of Explosives. Part 1. Effect of Ethyl Centralite on the Properties of an RDX-Based PBX

The effects of the addition of ethyl centralite, a commonly used stabilizer in double-base propellants, on a cyclotrimethylenetrinitramine (RDX)-based polymer-bonded explosive (PBX) were investigated. A reduction in sensitivity to impact was observed with increasing ethyl centralite content along with a reduction in explosiveness. Small-scale gap tests also show a reduction in sensitivity to shock initiation. High-performance liquid chromatography (HPLC) analysis of impact-stressed samples showed traces of 4-nitro- and 2-nitro-ethyl centralite and N-ethyl-N-nitrosoaniline; these results indicate the possibility that the mechanism of desensitization may, at least partially, be chemical in nature.     

Study of the ultrasound effects on yeast lees lysis in winemaking

This work focused on the study of ultrasound (US) treatment effects on wine lees, in order to verify the possibility of accelerating the protective colloids (i.e., polysaccharides) release. Moreover, these effects were compared with the usual practices of aging wine over lees and with the enzyme treatment of lees by means of beta-glucanases able to demolish the glucans and facilitate the release of intracellular components. This work was performed considering the possibility of setting up a technology applicable in a cellar. Ultrasound treatment on wine lees resulted in an increase in total colloids, proteins, and polysaccharides in the medium with a reduction in the colloids particle diameter. These results were mainly correlated with treatment duration rather than its intensity. Treatment at 90 % amplitude for 3 min provided good enough results in terms of colloids release, and therefore, it was used for the comparative study with natural lysis and enzyme treatment. The parameters evaluated showed that the ultrasound treatment resulted in an increased release of colloids from yeast (polysaccharides and glycoproteins); therefore, a significant effect on the extraction of cellular components compared to the long stay on the lees was detected, indicating the interesting advantage that this new technological application can bring to the winemaking process.     

A medial‐axis‐based model for propagating cracks in a regularised bulk

A new continuous‐discontinuous strategy for the simulation of failure is presented. The continuous bulk is regularised by means of a gradient‐enhanced damage model, where non‐locality is introduced at the level of displacements. As soon as the damage parameter is close or equal to 1, a traction‐free crack is introduced. To determine the direction of crack growth, a new criterion is proposed. In contrast to traditional techniques, where mechanical criteria are used to define the crack path, here, a geometrical approach is used. More specifically, given a regularised damage field D( x ), we propose to propagate the discontinuity following the direction dictated by the medial axis of the isoline (or isosurface in 3D) D( x ) = D*. The proposed approach is tested on different two‐dimensional and three‐dimensional examples that illustrate that this combined methodology is able to deal with damage growth and material separation. Copyright © 2014 John Wiley & Sons, Ltd.     

Thermal Conductivity of Saturated Liquid Toluene by Use of Anodized Tantalum Hot Wires at High Temperatures

Absolute measurements of the thermal conductivity of a distilled and dried sample of toluene near saturation are reported. The transient hot-wire technique with an anodized tantalum hot wire was used. The thermal conductivities were measured at temperatures from 300 K to 550 K at different applied power levels to assess the uncertainty with which it is possible to measure liquid thermal conductivity over wide temperature ranges with an anodized tantalum wire. The wire resistance versus temperature was monitored throughout the measurements to study the stability of the wire calibration. The relative expanded uncertainty of the resulting data at the level of 2 standard deviations (coverage factor k = 2) is 0.5 % up to 480 K and 1.5 % between 480 K and 550 K, and is limited by drift in the wire calibration at temperatures above 450 K. Significant thermal-radiation effects are observed at the highest temperatures. The radiation-corrected results agree well with data from transient hot-wire measurements with bare platinum hot wires as well as with data derived from thermal diffusivities obtained using light-scattering techniques.     

Dielectric Constant of the Nearly Azeotropic Mixture R410A1

The purpose of this paper is to present dielectric constant measurements of R410A, a chlorine-free refrigerant, which is a 50/50 (mass %) mixture of R32/125. The measurements on R410A were performed as a function of pressure and temperature ranging from 2 to 16 MPa and from 217 to 304 K, respectively, by using a direct capacitance method. The values of dielectric constant have an estimated repeatability of ±0.01% and an accuracy of ±0.1%. The data were correlated as a function of density and pressure. The theory developed by Vedam et al., and adapted by Diguet, and the Kirkwood modification of the Onsager equation for the variation of the modified molar polarization with temperature and density were applied to analyze the data and to obtain the dipole moment of R410A in the liquid state. This was found to be 3.31 Debye.     

Supported Cu(II) polymer catalysts for aqueous phenol oxidation

Supported Cu(II) polymer catalysts were used for the catalytic oxidation of phenol at 30 degrees C and atmospheric pressure using air and H(2)O(2) as oxidants. Heterogenisation of homogeneous Cu(II) catalysts was achieved by adsorption of Cu(II) salts onto polymeric matrices (poly(4-vinylpyridine), Chitosan). The catalytic active sites were represented by Cu(II) ions and showed to conserve their oxidative activity in heterogeneous catalysis as well as in homogeneous systems. The catalytic deactivation was evaluated by quantifying released Cu(II) ions in solution during oxidation, from where Cu-PVP(25) showed the best leaching levels no more than 5 mg L(-1). Results also indicated that Cu-PVP(25) had a catalytic activity (56% of phenol conversion when initial Cu(II) catalytic content was 200 mg L(Reaction)(-1)) comparable to that of commercial catalysts (59% of phenol conversion). Finally, the balance between activity and copper leaching was better represented by Cu-PVP(25) due to the heterogeneous catalytic activity had 86% performance in the heterogeneous phase, and the rest on the homogeneous phase, while Cu-PVP(2) had 59% and CuO/gamma-Al(2)O(3) 68%.     

A simplified methodology to determine the cutting stiffness and the contact stiffness in the plunge grinding process

This paper presents a simplified experimental technique to determine approximately the cutting stiffness and the contact stiffness in the plunge grinding process. The experimental methodology consists of a machine static stiffness test and several grinding processes. The cutting stiffness is obtained from the workpiece headstock static stiffness and from its displacement during the grinding processes, measured by a LVDT transducer. The contact stiffness is resolved from the expression that relates it with the grinding process time constant and other grinding parameters. The time constant is obtained from the exponential that characterises the machine deformation during the spark-out, measured as well by the LVDT transducer placed on the workpiece headstock. The variation of the obtained values of the contact stiffness with some of the grinding parameters is also shown.     

Microporous and mesoporous materials with isolated vanadium species as selective catalysts in the gas phase oxidation reactions

The preparation of V-containing micro- and mesoporous (silicates, aluminosilicates and aluminophosphates) materials as well as the nature of V species incorporated in framework positions is reviewed. In addition, the catalytic performance of V-silicalite, VAPO-5 and V-MCM-41 in the gas phase selective oxidation of hydrocarbons has also been compared.     

BMP9-Induced Survival Effect in Liver Tumor Cells Requires p38MAPK Activation

The study of bone morphogenetic proteins (BMPs) role in tumorigenic processes, and specifically in the liver, has gathered importance in the last few years. Previous studies have shown that BMP9 is overexpressed in about 40% of hepatocellular carcinoma (HCC) patients. In vitro data have also shown evidence that BMP9 has a pro-tumorigenic action, not only by inducing epithelial to mesenchymal transition (EMT) and migration, but also by promoting proliferation and survival in liver cancer cells. However, the precise mechanisms driving these effects have not yet been established. In the present work, we deepened our studies into the intracellular mechanisms implicated in the BMP9 proliferative and pro-survival effect on liver tumor cells. In HepG2 cells, BMP9 induces both Smad and non-Smad signaling cascades, specifically PI3K/AKT and p38MAPK. However, only the p38MAPK pathway contributes to the BMP9 growth-promoting effect on these cells. Using genetic and pharmacological approaches, we demonstrate that p38MAPK activation, although dispensable for the BMP9 proliferative activity, is required for the BMP9 protective effect on serum withdrawal-induced apoptosis. These findings contribute to a better understanding of the signaling pathways involved in the BMP9 pro-tumorigenic role in liver tumor cells.     

Rare Titin (TTN) Variants in Diseases Associated with Sudden Cardiac Death

A leading cause of death in western countries is sudden cardiac death, and can be associated with genetic disease. Next-generation sequencing has allowed thorough analysis of genes associated with this entity, including, most recently, titin. We aimed to identify potentially pathogenic genetic variants in titin. A total of 1126 samples were analyzed using a custom sequencing panel including major genes related to sudden cardiac death. Our cohort was divided into three groups: 432 cases from patients with cardiomyopathies, 130 cases from patients with channelopathies, and 564 post-mortem samples from individuals showing anatomical healthy hearts and non-conclusive causes of death after comprehensive autopsy. None of the patients included had definite pathogenic variants in the genes analyzed by our custom cardio-panel. Retrospective analysis comparing the in-house database and available public databases also was performed. We identified 554 rare variants in titin, 282 of which were novel. Seven were previously reported as pathogenic. Of these 554 variants, 493 were missense variants, 233 of which were novel. Of all variants identified, 399 were unique and 155 were identified at least twice. No definite pathogenic variants were identified in any of genes analyzed. We identified rare, mostly novel, titin variants that seem to play a potentially pathogenic role in sudden cardiac death. Additional studies should be performed to clarify the role of these variants in sudden cardiac death.