透明蓝宝石高压相平衡池及其应用

主要描述了全透明高压相平衡池。该池全部用人造蓝宝石制造,其最大工作压力为50MPa,工作温度为20—200℃。应用该装置,可以目测混合物的相态变化和测定 P-V-T 关系。本文还就 CH_4-C_(16)H_(34)二元体系汽液相界的测定具体阐明其应用。

Theoretical prediction of structural,electronic and optical properties of quaternary alloy Zn_(1-x)Be_xS_ySe_(1-y)

Within density functional theory based on the full potentiM-linearized augmented plane wave method, we carry out the first-principles calculation of the structural, electronic, and optical properties of the zinc blende quaternary alloy Zn1-xBexSySe1-y. The Perdew-Burke-Ernzerhof generaized gradient approximation based on the optimization of total energy and the Engel-Vosko generalized gradient approximation based on the optimization of the corresponding potential are used. Our investigation on the effect of the composition on lattice constants, bulk modulus, band gap, optical dielectric constant, and refractive index shows a non-linear dependence. The energy gap Eg（x, y） has been determined over the entire compositions x and y. In addition, the energy band gap of the technologically important quaternary alloy Znl-xBexSySe1-y in conditions of being lattice matched to ZnS substrate has been investigated. It is noteworthy that the present work is the first theoretical study of the quaternary alloy of interest.

Energy Efficiency of Briquettes Derived from Three Agricultural Waste’s Charcoal Using Two Organic Binders

Waste management could contribute significantly to reducing environmental degradation. Studies showed that briquetting provides with or without binder helps to manage wastes as energy fuels. However, the properties of many binders are not investigated extensively. This work investigated the effect of two organic binders’ low rate on energy efficiency of Briquettes produced from charcoals of Tender Coconut Husks (TCH), Palm Kernel Shells (PKS) and Corn Cobs (CC). Bombax Costatum calyx (B) and Cissus Repens barks (C) were used separately as binders to elaborate briquettes. The briquettes were compared based on their energy efficiency parameters with wood charcoal as control. Energy efficiency parameters such as water boiling time (WBT), mass of biomass used (MB), burning rate (BR), temperature rise rate (TR) and maximum temperature in the furnace (Tmax) were measured from each biomass charcoal briquette and wood charcoal combustion. Water boiling test was applied to determine briquettes thermal properties. The results of WBT, BR, TR and Tmax were respectively within the ranges 3.4 - 12.3 min, 2.90 - 7.71 g/min, 4.63°C/s - 16.10°C/s and 623°C - 900°C. Corn Cobs charcoal briquettes with Bombax binder took the shortest time to boil water and also presented a high temperature rise rate and the highest maximum temperature. The lowest burning rates were obtained for Tender coconut husks charcoal briquettes with Cissus binder. They showed good material conservation for bombax bound briquettes. The results of our investigations showed that binders content increasing enhanced the thermomechanical stability and affected negatively the energy efficiency parameters of the studied briquettes.

Origanum majorana Extracts as Mild Steel Corrosion Green Inhibitors in Aqueous Chloride Medium

We optimized Origanum majorana (OM) extraction for mild steel corrosion inhibition in neutral 0.5 M chloride medium. The inhibition mechanism evolved in presence of the optimal extract was discussed when calculating the activation energy (Ea), the activation enthalpy (ΔaH) as well as the activation entropy (ΔaS). The OM extract molecules were investigated using the density functional theory (DFT) at B3LYP/6-31G(d,p) basis set level. 1-methyl-4-propan-2-ylcyclohexa-1,3-diene alpha-terpinene was predicted exhibiting the most inhibition capabilities.

Unveiling the Residual Stresses,Local Micromechanical Properties and Crystallographic Texture in a Ti-6Al-4V Weld Joint

In this work,the micromechanical properties,crystallographic texture,welding residual stresses and their evolution after plastic strain were investigated in a Ti-6Al-4V alloy tungsten inert gas weld joint.It was found that the welding process affected the Young modulus and microhardness values in bothαandβphases in the different regions of the weld joint.The highest microhardness and Young modulus values of a phase were recorded in the heat-affected zone,whereas the highest values of these characteristics for theβphase were found in the fusion zone(FZ).The change in the micro mechanical properties was accompanied by a change in the crystallographic texture components of the dominant a phase from(0001)<10-10>and(11-20)<10-10>components in the base material to(10-10)<11-20>and(11-20)<3-302>components in the FZ.The introduction of tensile testing resulted in a continuous stress relaxation and improved the weld joint performances.

Sound scattering in dense granular media

The sound propagation in a dense granular medium is basically characterized by the ratio of wavelength to the grain size. Two types of wave transport are distinguished: one corresponds to coherent waves in the long wavelength limit, the other to short-wavelength scattered waves by the inhomogeneous contact force networks. These multiply scattered elastic waves are shown to exhibit a diffusive characteristics of transport over long distances of propagation. Determination of the transport mean free path l * and the inelastic absorption (Q-1) allows the inference of the structural properties of the material such as the heterogeneity and internal dissipation. The relevance of our experiments for seismological applications is discussed. Moreover, we apply the correlation technique of the configuration-specific sound scattering to monitoring the dynamic behaviour of the granular medium (irreversible rearrangements) under strong vibration, shearing and thermal cycling, respectively.

DFT Investigation of Structural,Electronic,Elastic and Optical Properties of SrMO_4(M=Mo and W)

A planes waves pseudo-potential calculations are performed for the SrMO4 （M=Mo and W） compound in order to investigate the structural, electronic, elastic and optical properties. The calculated lattice constants are in good agreement with experiment ones. The electronic structures show that SrMO4 has a direct band gap situated at F point. The calculated elastic constants indicate that both structures are mechanically stable. The bulk modulus, shear modulus, Young＇s modulus and Poisson ratio are investigated from the elastic constants, in the same time the anisotropy of the elastic properties is discussed. The imaginary part of the dielectric functions is calculated and the contributions of various transitions peaks are analyzed. Furthermore, the other optical properties such as absorption coefficient I（w）, optical reflectivity R（w）, energy-loss spectrum L（w）, and the refractive index n（w） have been investigated.

Preliminary assessment of natural radioactivity and associated radiation hazards in a phosphate mining site in southern area of Togo

Introduction Because of the increasing use of phosphate in industries worldwide,especially in Togo,it is interesting to investigate the potential radioactivity exposure of phosphate ores,especially in the one being exploring in Togo nowadays.Material and methods The contents of natural radionuclides(40K,226Ra,232Th,235U and 238U)were assessed in phosphate soil samples from Kpogamé,Dagbati and Kpéméin the maritime region of Togo by using gamma spectrometry-based Broad Energy Germanium detector(BEGe6530).Since no study was made prior to the exploitation,the samples from the control area of Anfoin-Kpota far away from the three others were considered as reference.Results and discussion The results are discussed and compared with the data from other countries.The activity concentration of 40K,226Ra,232Th,235U and 238U are between(59.45 and 129.99),(20.19 and 779.93),(16.81 and 121.42),(2.26 and 52.03)and(16.66 and 841.14)Bq kg^(−1),respectively.The values obtained shows that the exploitation sites(Dagbati and Kpogamé)and treatment site(Kpémé)have a very high level of radioactivity than the control area(Anfoin-Kpota).The Kpogaméand Dagbati exploitation and Kpéméwaste discharging phosphate deposit sites were found to have higher activity concentration than many others exploited phosphate sedimentary deposits around the world.The average annual effective dose of the above studied sites is 0.36,0.24 and 0.48 mSv year−1,respectively.The value related to the discharge waste site is about 2%of the 1.0 mSv year−1 recommended by the International Commission on Radiological Protection as the maximum annual dose to the public.Conclusions The obtained result of both radioactivity and radiological level in the studied areas will be considered as a pre-operational baseline to estimate the possible radiological impacts due to mining and processing phosphate industrial activities.