Shape controlled zeolite EU-1 (EUO) catalysts: Dry gel conversion type synthesis, characterization and formation mechanisms

Shape controlled zeolite EU-1 (EUO) catalysts were synthesized by a dry gel conversion (DGC) type synthesis. Silica extrudates as starting material were impregnated to the incipient wetness point and subjected to a hydrothermal treatment under water vapor. All-zeolite extrudates with the same size and shape as initial silica extrudates were obtained. Formation mechanisms were investigated by varying the initial extrudate water content. Hydrothermal treatment was carried out in the presence or in the absence of an external water source. Extrudate H₂O/SiO₂ molar ratios of at least 1.5 were required to obtain zeolite extrudates with high crystallinity. In the presence of an external water source, a non-uniform progression of zeolite crystallization from the outer to the inner extrudate surface was observed. On the contrary in the absence of an external water source, first crystals appeared throughout the extrudates. For both methods, mesopores of silica extrudates disappeared during impregnation processes and micro- and macropores were formed during crystallization. In a m-xylene isomerization reaction shape controlled zeolite EU-1 extrudates display an enhanced p-xylene selectivity.     

Cigarette Smoke Condensate Exposure Induces Receptor for Advanced Glycation End-Products (RAGE)-Dependent Sterile Inflammation in Amniotic Epithelial Cells

Maternal smoking is a risk factor of preterm prelabor rupture of the fetal membranes (pPROM), which is responsible for 30% of preterm births worldwide. Cigarettes induce oxidative stress and inflammation, mechanisms both implicated in fetal membranes (FM) weakening. We hypothesized that the receptor for advanced glycation end-products (RAGE) and its ligands can result in cigarette-dependent inflammation. FM explants and amniotic epithelial cells (AECs) were treated with cigarette smoke condensate (CSC), combined or not with RAGE antagonist peptide (RAP), an inhibitor of RAGE. Cell suffering was evaluated by measuring lactate dehydrogenase (LDH) medium-release. Extracellular HMGB1 (a RAGE ligand) release by amnion and choriodecidua explants were checked by western blot. NF-κB pathway induction was determined by a luciferase gene reporter assay, and inflammation was evaluated by cytokine RT-qPCR and protein quantification. Gelatinase activity was assessed using a specific assay. CSC induced cell suffering and HMGB1 secretion only in the amnion, which is directly associated with a RAGE-dependent response. CSC also affected AECs by inducing inflammation (cytokine release and NFκB activation) and gelatinase activity through RAGE engagement, which was linked to an increase in extracellular matrix degradation. This RAGE dependent CSC-induced inflammation associated with an increase of gelatinase activity could explain a pathological FM weakening directly linked to pPROM.     

Kinetics of the vapour-phase hydrogenation of benzene over a supported nickel catalyst in a stirred-vessel reactor

The catalytic hydrogenation of benzene was investigated over a supported nickel catalyst in a continuous stirred-vessel reactor between 260° and 450°F at atmospheric pressure. The effects of temperature, ratio of hydrogen to benzene and total feed rate (or contact time) on the conversion of benzene and yield of cyclohexane were determined. The use of the stirred reactor helped to eliminate mass transfer limitations. The investigation was carried out using surface-coated catalysts in order to eliminate pore diffusion which might otherwise mask the actual kinetics. Studies of the mixing characteristics of the reactor were carried out under both reacting and non-reacting conditions, by following conversion as a function of stirrer speed and by a tracer (pulse) technique, respectively. The kinetic data were analysed to determine the most probable model to represent the reaction. The Houghen–Watson type analysis was carried out using non-linear least squares instead of the usual linear one. The model that satisfactorily correlated the data over the entire temperature range describes the rate-controlling step as the surface reaction between adsorbed hydrogen and adsorbed benzene, the hydrogen addition being simultaneous. The following Hougen–Watson type equation was proposed: r = k_e K_H ³K_B P_H ³P_B/(1+K_HP_H+K_BP_B+K_CP_C)⁴. The constants in this rate equation were expressed as a function of temperature.     

Automatic segmentation of cells from microscopic imagery using ellipse detection

Cell image segmentation is a necessary first step of many automated biomedical image-processing procedures. There certainly has been much research in the area. To this, a new method has been added, which automatically extracts cells from microscopic imagery, and does so in two phases. Phase 1 uses iterated thresholding to identify and mark foreground objects or `blobs' with an overall accuracy of >97%. Phase 2 of the method uses a novel genetic algorithms-based ellipse detection algorithm to identify cells, quickly and reliably. The mechanism, as a whole, has an accuracy rate >96% and takes <1 min (given our specific hardware configuration) to operate on a microscopic image     

Whodunnit – Searching for the most important feature types signalling emotion-related user states in speech

In this article, we describe and interpret a set of acoustic and linguistic features that characterise emotional/emotion-related user states – confined to the one database processed: four classes in a German corpus of children interacting with a pet robot. To this end, we collected a very large feature vector consisting of more than 4000 features extracted at different sites. We performed extensive feature selection (Sequential Forward Floating Search) for seven acoustic and four linguistic types of features, ending up in a small number of ‘most important’ features which we try to interpret by discussing the impact of different feature and extraction types. We establish different measures of impact and discuss the mutual influence of acoustics and linguistics.     

Using immersive virtual reality and anatomically correct computer-generated characters in the forensic assessment of deviant sexual preferences

Penile plethysmography (PPG) is the gold standard for the assessment of sexual interests, especially among sex offenders of children. Nonetheless, this method faces some ethical limitations inherent to the nature of its stimuli and could benefit from the improvement of its ecological validity. The use of computer-generated characters (CGC) in virtual immersion for PPG assessment might help address these issues. A new application developed to design made-to-measure anatomically correct virtual characters compatible with the Tanner developmental stages is presented. The main purpose of this study was to determine how the virtual reality (VR) modality compares to the standard auditory modality on their capacity to generate sexual arousal profiles and deviance differentials indicative of sexual interests. The erectile responses of 22 sex offenders of children and 42 non-deviant adult males were recorded. While both stimulus modalities generated significantly different genital arousal profiles for sex offenders of children and non-deviant males, deviance differentials calculated from the VR modality allowed for significantly higher classification accuracy. Performing receiver operating characteristic analyses further assessed discriminant potential. Auditory modality yielded an area under the curve (AUC) of 0.79 (SE = 0.059) while CGC in VR yielded an AUC of 0.90 (SE = 0.052). Overall, results suggest that the VR modality allows significantly better group classification accuracy and discriminant validity than audio stimuli, which provide empirical support for the use of this new method for PPG assessment. Additionally, the potential use of VR in interventions pertaining to self-regulation of sexual offending is addressed in conclusion.     

Catalytic oxidation of benzene to maleic anhydride in a continuous stirred tank reactor

The kinetics of the vapor phase oxidation of benzene has been studied over an industrial catalyst in a continuous stirred tank reactor in the temperature range from 280 to 430°C and at atmospheric pressure. The products obtained are maleic anhydride, carbon oxides and water. The rate of the overall reaction (disappearance of benzene) is represented by the following expression based upon a steady state adsorption model The rate of formation of maleic anhydride is correlated by the equation which allows for a homogeneous depletion of maleic anhydride. The rate constants k_B, k_O, k_2(g) were found to follow Arrhenius behavior.      

基于Livermore模型CT图片构建人体躯干数字体模及其在肺部计数器虚拟刻度中的应用

基于Livermore 人体躯干物理模型CT图片构建数字体模,并结合蒙特卡罗程序MCNP对一套由四个宽能高纯锗探测器(BEGe)构成的肺部计数器进行了虚拟刻度.首先,利用点源(241Am,137Cs,60Co,54Mn,57Co,109Cd) 实验数据,对高纯锗晶体尺寸进行调整以获得正确的探测器几何参数,在γ射线能量13.9 keV～1332.5 keV范围内,调整后四个探测器全能峰效率实验测量的平均值与蒙特卡罗计算值的差别在±10%范围内.之后,对不同胸壁厚度(CWT=19 mm, 25 mm, 30 mm, 43 mm)躯干体模进行CT扫描获得其CT图片,利用Dosigray软件对CT图片进行分割后,连同探测器几何描述文件输入到OEDIPE软件,生成数字体模虚拟刻度用MCNP输入程序.最后,利用241Am、152Eu肺部源对数字体模虚拟刻度结果进行了实验验证,结果表明:在59.5 keV～1408 keV能量范围内,虚拟刻度结果与实验结果的差别在±10%之间;对于17.5 keV能量,差别在±30%之间.     

The influence of the processing route on the fragmentation of (Nb,Ti)C stringers and its role on mechanical properties and hydrogen embrittlement of nickel based alloy 718

The nickel-base superalloy 718 is a precipitation hardened alloy widely used in the nuclear fuel assembly of pressurized water reactors (PWR). However, the alloy can experience failure due to hydrogen embrittlement (HE). The processing route can influence the microstructure of the material and, therefore, the HE degree. In particular, the size and distribution of the (Nb,Ti)C particles can be affected by the processing. In this regard, the objective of this work was to analyze the influence of cold and hot deformation processing routes on the development of the microstructure, and the consequences on mechanical properties and hydrogen embrittlement. Tensile samples were hydrogenated through gaseous charging and compared to non-hydrogenated samples. Characterization was performed via scanning and transmission electron microscopies, as well as electron backscattered diffraction. The processing was effective to promote significant variations in average grain size and length fraction of special Σ3ⁿ boundaries, as well as reduction of average (Nb,Ti)C particle size, being these changes more intense for the cold-rolled route. For the mechanical properties, on one side, the cold-rolled route presented the highest increase in ductility for non-hydrogenated samples, while, on the other side, had the highest degree of embrittlement under hydrogen. This dual behavior was attributed to the interaction of hydrogen with the (Nb,Ti)C particles and stringers and its ensuing influence on the fracture processes.     

Decontamination of petroleum sludges by hot water extraction

The process of hot water extraction of tar sand was modified and adapted for removal of heavy oil from bottom tank petroleum sludges, and was submitted to a laboratory feasibility study. This process can also be utilized to clean beach sands contaminated by accidental heavy oil spills. In the case of oil contaminated sands, a single stage extraction has yielded a 99% recovery of hydrocarbons and clean sands (containing less than 0.1% of hydrocarbons) which are thus safe to be returned to the environment. In the case of petroleum bottom tank sludge, it was necessary to proceed with a double stage extraction with the addition of a wetting agent. A dosage of a Na₂ Si O₃ aqueous solution of 1% by weight has proven efficient, allowing an 82% recovery of hydrocarbons, with only 0.5% of hydrocarbons content in the solid residues.