亚太地区原油供需贸易展望

当前亚太原油市场的情况可以用“产量增长缓慢、出口量下降和进口需求上升”这三句话来概括。中东仍将是亚太原油进口的主要来源,而亚太未来从大西洋盆地所进口的原油在该地区市场中所占的比例也将上升,与之相对应的则是亚太自产原油份额在这一地区整个供应比例中将缩小。本文所讨论的问题涉及到亚太的原油产量、出口量以及进口需求,同时对这一地区的主要产油国和原油进出口国的情况做了概述。此外,文章还兼顾了亚太地区原油定价的现行体制,并在最后对这一地区未来石油进口依赖性的增长形势进行了预测。     

The use of surface metrology instrumentation to measure rates of wear of internal combustion engine components

A study was made of the effects of operating conditions on internal combustion engine service life. It was found after extensive investigation of major engine components (piston, piston rings, bearings and cylinder liner) that engine service life appears to be more a function of the acceptable wear of the cylinder liner than of any other engine parts.A method was developed to determine the amount of cylinder liner wear; this involved measuring the depth of scratch marks (using Talysurf model 3 or Surtronic 3 instruments). We describe the method employed and the results; these are at least as reliable as and give more details than conventional methods.     

Analyzing combinations of circular birefringence,linear birefringence,and elliptical dichroism in magneto-optical rotators

We derive analytic expressions for the polarization characteristics of light emerging from a magneto-optical medium possessing arbitrary contributions from linear and circular birefringence as well as magnetic circular dichroism. The medium is placed inside a static magnetic field. The rotation of the plane of polarization and the ellipticity of the resultant light exhibit interesting characteristics that can be a useful guide in the design and analysis of new photonic devices. Furthermore, the Jones matrices are derived in all cases, including for elliptical dichroism, indicating the role of hyperbolic trigonometric functions in modeling the effects of dichroism. Finally, implications for experimental detection of the polarization state and the limits on the performance of optical isolators are discussed.     

Application of Magnetic Susceptibility to Study Low Iron Substitution in Tricalcium Aluminate

The magnetic susceptibilities of the tricalcium aluminate prepared containing 0.5, 1, or 2 wt% FeC₂O₄ or Fe₂O₃ before firing were measured at different temperatures and different magnetic field intensities. The Curie temperature of each compound is determined from the magnetic susceptibility temperature curves. The values of the effective magnetic moments were calculated from the experimental data for the different compounds. The variations in the magnetic properties and the magnetic constants with the type and concentration of iron added to C₃A confirm that the magnetic susceptibility measurements could be considered a good tool to estimate the solubility limit of iron in different forms in C₃A. Our data confirm also the previous data of IR measurements for such samples at low iron concentrations.     

Roman Urdu toxic comment classification

Language Resources and Evaluation - With the increasing popularity of user-generated content on social media, the number of toxic texts is also on the rise. Such texts cause adverse effects on...     

Optical,FTIR and DC Conductivity of Soda Lime Silicate Glass Containing Cement Dust and Transition Metal Ions

Four soda lime silicate glass samples of composition (70 % SiO₂+ 20 % Na₂O+ 10 % CaO mol %) were prepared after adding 5 wt% cement dust to each sample mixture besides 0.1 wt% of one transition metal (TM) oxide of Fe, Co or Cu. The four samples were melted by a conventional melt-annealing technique at 1400 ^°C for 2.5 h. Density, UV/VIS, FTIR and DC conductivity measurements were performed for each glass. Experimental results indicate that there are only slight differences in the density values. The optical spectra reveal that the TM free sample and the sample containing iron ions have the same spectral features while the samples containing copper or cobalt exhibit distinct characteristic absorption bands due to each TM ion. FTIR spectra reveal characteristic vibrational bands due to stretching and bending modes of the silicate network. DC conductivity data show variations in the values of the studied samples according to the type of TM ions added. All the experimental results were correlated with each other in accordance with the current views on the constitution of the studied glasses.     

An analysis of bioclimatic zones and implications for design of outdoor built environments in Egypt

Climate considerations are essential dimensions in the assessment of quality of outdoor built environments. This paper provides an analysis of bioclimatic classification of Egypt to help the environmental design of wide range of purposes, including: climate responsive design; energy conservation and thermal comfort in the outdoor built environments. The analysis of this classification uses a bioclimatic approach in which the comfort zone and monthly climatic lines were determined and plotted on the psychrometric chart. Since the mean radiant temperature (T_mrt) is the most important input parameter for the energy balance in outdoor environments, the charts apply the ASHRAE 55-2004 standard considering the operative temperature as a function of T_mrt. Analysis for each bioclimatic zone determines the potential of passive design strategies to maintain thermal comfort in outdoor spaces and to contribute to energy efficient built environment. Finally, this study suggests a design guideline matrix for landscape architectural design for the different bioclimatic zones.