Sulphur and oxygen isotopic characters of dissolved sulphate in groundwater from the Pleistocene aquifer in the southern Jordan Valley (Jericho area, Palestine)

Sulphate and chloride concentrations in the shallow Pleistocene aquifer systems in the lower Jordan valley area indicate a general trend of increasing salinity eastward and southward. This study was conducted in one of the important sub-basins feeding the Pleo-Pleistocene aquifer in the Jericho area in the southern part of the valley using S and O isotopes of dissolved sulphate. The results show that sulphate has mainly two contributions to the groundwater. One is the surface seepage, which is present as a salty leachate form with the positive delta34Ssulphate values of primary gypsum in Lisan and Samara formations, and the second is the upwelling saline water which was in contact with a deep secondary gypsum, aragonites and salty rocks and rose up under heavy abstraction with depleted 34S in sulphate and relatively high sulphate and chloride content. The latest was clearly shown in the Arab Project wells to the east that is undergoing a continuous heavy abstraction. The isotopic signatures of S and O in these wells to the east show that this depleted 34S and highly concentrated sulphate might also indicate a dissolved sulphate originating from pyrite oxidation that results from the interaction with a pyrite-rich aquifer, which can well up with salty water under heavy abstraction and is oxidised in the upper aerobic shallow aquifer.     

Transient heating of a rotating elastic-plastic solid shaft

Based on Tresca's yield criterion and the flow rule associated with it, the transient plasticization in a rotating elastic–plastic solid shaft with temperature dependent yield stress subject to a temperature cycle is studied. Special attention is paid to the residual stresses. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Experimental and numerical investigation of transition to turbulent flow and heat transfer inside a horizontal smooth rectangular duct under uniform bottom surface temperature

In this study, steady-state turbulent forced flow and heat transfer in a horizontal smooth rectangular duct both experimentally and numerically investigated. The study was carried out in the transition to turbulence region where Reynolds numbers range from 2,323 to 9,899. Flow is hydrodynamically and thermally developing (simultaneously developing flow) under uniform bottom surface temperature condition. A commercial CFD program Ansys Fluent 12.1 with different turbulent models was used to carry out the numerical study. Based on the present experimental data and three-dimensional numerical solutions, new engineering correlations were presented for the heat transfer and friction coefficients in the form of $ {\text{Nu}} = {\text{C}}_{2} {\text{Re}}^{{{\text{n}}_{ 1} }} $ and $ {\text{f}} = {\text{C}}_{3} {\text{Re}}^{{{\text{n}}_{3} }} $ , respectively. The results have shown that as the Reynolds number increases heat transfer coefficient increases but Darcy friction factor decreases. It is seen that there is a good agreement between the present experimental and numerical results. Examination of heat and mass transfer in rectangular cross-sectioned duct for different duct aspect ratio (α) was also carried out in this study. Average Nusselt number and average Darcy friction factor were expressed with graphics and correlations for different duct aspect ratios.     

双金属镍-锰／γ-Al2O3催化剂对甲烷二氧化碳重整反应的影响

用浸渍法制备γ-Al2O3负载的Ni-Mn双金属催化剂．在500-700。C按照17：17：2的C02／CHa／N2比例,以36mL／min的载气流速进行甲烷二氧化碳重整反应,利用甲烷二氧化碳的转化率、生成的合成气H2／CO比例以及长期稳定性等指标评价了催化剂的催化性能．实验表明,添加Mn提高催化性能并使双金属催化剂的稳定性更高,比单金属催化剂更好地抑制焦炭生成,Mn最合适的添加量为0．5wt％．通过BET、C02-TPD、TGA、XRD、SEM、EDX和FTIR各种技术对催化剂进行了表征．     

Comparison of simulation methods for electronic structure calculations with experimental electron energy-loss spectra

The electronic structure of hexagonal GaN is studied using two simulation techniques in order to develop a method to interpret the fine-structure of an experimental nitrogen K-edge electron energy loss spectrum obtained using a scanning transmission electron microscope. The application of these simulation methods to the bulk spectrum is a necessary first step in developing a fundamental understanding of the effect of changes in the electronic structure on the properties of defects. It is found here that both of the techniques used, multiple scattering (MS) and density functional theory (DFT), produce excellent agreement with the experimental bulk spectrum. The MS method is limited in accuracy but efficient in time, while the DFT method is more accurate but time consuming. Through the combination of these methods, experimental energy loss spectra can be readily understood, and a means to unravel the complexities of the electronic structure can be determined.     

Cytotoxic effect,enzyme inhibition,and in silico studies of some novel N-substituted sulfonyl amides incorporating 1,3,4-oxadiazol structural motif

Molecular Diversity - The acetylcholinesterase and carbonic anhydrase inhibitors (AChEIs and hCAIs) remain key therapeutic agents for many bioactivities such as anti-Alzheimer and antiobesity...     

Experimental investigation of flow and heat transfer in rectangular cross-sectioned duct with baffles mounted on the bottom surface with different inclination angles

In this study, steady-state forced convection heat transfer and pressure drop characteristics in a horizontal rectangular cross-sectioned duct, baffles mounted on the bottom surface with different inclination angles were investigated experimentally in the Reynolds number range from 1 × 10³ to 1 × 10⁴. The study was performed under turbulent flow conditions. Effects of different baffle inclination angles on flow and heat transfer were studied. Results are also presented in terms of thermal enhancement factor. It is observed that increasing in baffle inclination angle enhances the heat transfer and causes an increase in pressure drop in the duct.     

Preparation and probe analysis of Langmuir–Blodgett films with metal-containing dendritic and cluster structures

We aim to reveal the influence of?pH values of the working solution on spatial arrangement of metal-containing inclusions in the monolayer coatings prepared by Langmuir?CBlodgett (LB) technology and transferred to solid substrates with consequent modification of surface electrical properties. Consequently, films with inclusions in the form of dendrites and cluster shapes have been obtained. Submicron and micron lead-containing formations in Langmuir?CBlodgett films have been characterized by using the atomic force microscopy, Kelvin probe microscopy, and scanning electron microscopy methods. The results show that increasing?pH value of the subphase has caused the significant changes in the shape and composition of the inclusions in Langmuir?CBlodgett films. The synthesized inclusions on the solid substrate surface resulted in formation of the regions with the local electric fields and, as consequence, to significant modification of the structure and electrical properties. The location and length of the regions with surface potential disturbance depend on the shape of inclusions, and consequently, on?pH value of the subphase used in LB technology.     

Micro-wires self-assembled and 3D-connected with the help of a nematic liquid crystal

We discuss a method for producing automatic 3D connections at right places between substrates in front of one another. The idea is based on the materialization of disclination lines working as templates. The lines are first created in the nematic liquid crystal (5CB) at the very place where microwires have to be synthesized. Due to their anchoring properties, colloids dispersed into the nematic phase produce orientational distortions around them. These distortions, which may be considered as due to topological charges, result in a nematic force, able to attract the colloids towards the disclinations. Ultimately, the particles get trapped onto them, forming micro- or nano-necklaces. Before being introduced in the nematic phase, the colloids are covered with an adhering and conducting polypyrrole film directly synthesized at the surface of the particles (heterogeneous polymerization). In this manner, the particles become conductive so that we may finally perform an electropolymerization of pyrrole monomers solved in 5CB, and definitely stick the whole necklace. The electric connection thus synthesized is analyzed by AFM, and its strength is checked by means of hydrodynamic tests. This wiring method could allow Moore's law to overcome the limitations that arise when down-sizing the electronic circuits to nanometer scale.     

Crystallization kinetic studies on Bi1.75Pb0.25Sr2Ca2Cu3-xSnxOδ glass-ceramic by using non-isothermal technique

The Sn substituted Bi_1.75Pb_0.25Sr₂Ca₂Cu_3-xSnxO_δ glass ceramic (where x = 0, 0.1, 0.3, and 0.5) samples were prepared by the melt-quenching method. Crystallization kinetic studies of the samples were conducted using the differential thermal analysis (DTA). The oxidation behavior of the samples was also analyzed using the thermogravimetry analysis (TG). The DTA curves were registered with different heating rates (5, 10, 15, and 20 Kmin^? 1) up to 1200 ± 0.5 K. The crystallization results were analyzed, and activation energy of crystallization process as well as the crystallization mechanisms and the effect of Sn substitution on powder glass ceramic were characterized. The glass transition temperature (T_g), the first crystallization peak temperature (T_x1) and the second crystallization peak temperature (T_x2) values were obtained as 713.0 ± 0.5–746.6 ± 0.5, 731.0 ± 0.5–760.8 ± 0.5 and 789.0 ± 0.5–820.1 ± 0.5 K, respectively. The activation energy (E_a) of crystallization was estimated from DTA results to be about 332.8 ± 0.1, 358.0 ± 0.1, 353.1 ± 0.1 and 348.9 ± 0.1 kJ/mol for x = 0, 0.1, 0.3 and 0.5, respectively, by using the Kissinger method. The Avrami parameter (n) values calculated at different Sn ratio from DTA results were found to be between 1.70 ± 0.01 and 2.57 ± 0.01, results reflect the growth of small particle with a decreasing nucleation rate.