Fault tectonics of the Shillong plateau and adjoining regions,north-east India using remote sensing data

The Shillong plateau in north-east India shows innumerable fracture lineaments on satellite images. In fact the whole plateau is criss-crossed by fractures. The plateau has been subjected to extensive compressional forces mainly in N-S and E-W directions resulting from the collision of the Indian plate with the Tibetan and Burmese plates, respectively. This type of plate tectonism has been responsible for the formation of many significant faults, folds and other tectonic features in the Shillong plateau and adjoining regions. The well known E-W trending Dauki fault, N-S trending faults, NE-SW trending shear zone and other prominent lineaments and their associated structural features could be studied on the basis of remote sensing techniques. Folding in soft sediments along the Dauki fault reveals the compression direction. Directional compressional tectonism has been expressed through lateral movements along the NE-SW trending shear zone and N-S trending faults and folds in the area just south of the Hatlong thrust. It has been observed from the studies that the Dauki fault zone and the areas in Bangladesh show various tectonic features, which are mostly controlled by vertical movements. Seismicity of the Shillong plateau is quite scattered all over the area. The occurrence of several deep earthquakes (> 1OOkm) indicate deep tectonic activities in the upper mantle. Earthquakes have been found to occur near some faults and this is probably an indication of recent activities along these faults.     

使用GIS技术支持下的地貌瞬时单位过程线估算设计洪水

在印度甘比希里河流域，应用GIS技术水陆两用全能信息系统软件建立数字高程模型进而建立1h间隔的流域等流时线图，估算出模型参数，并将每组设计暴雨数据、地貌特征、初始参数代入地貌瞬时单位线模型中，分别考虑单峰、双峰、三峡、四峰共4种情况计算出设计洪水过程线，并与其他方法进行比较。可以看到应用GIS技术较之手工方法更容易且更精确。     

Synthesis and characterization of polyaniline–ZnO composite and its dielectric behavior

Films of polyaniline (PANI) and PANI–zinc oxide (ZnO) composites have been synthesized by solution cast and spin coating technique. The ZnO powder of particle size 100–200 nm was synthesized by sol–gel technique and the polyaniline was synthesized by chemical oxidative polymerization of aniline. The composite films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infra red (FTIR) and the results were compared with polyaniline films. Dielectric properties of PANI and PANI–ZnO composite films have been investigated between frequency ranges of 8.5 and 13.0 GHz. The ‘a’ lattice parameter of ZnO was found to increase and the ‘c’ lattice parameter was found to decrease after ZnO–PANI composite formed. The characteristic FTIR peaks of PANI were found to shift to higher wave number in ZnO–PANI composite. These observed effects have been attributed to interaction of ZnO particles with PANI molecular chains. Dielectric constant of PANI–ZnO composite film was found to be smaller than the PANI film. The decrease of dielectric constant in PANI–ZnO films as compared to PANI was attributed to the interfaces formed between ZnO particles and PANI.     

ANALYSIS OF DIFFUSIVE AND CONVECTIVE RECOVERY OF FLUORESCENCE AFTER PHOTOBLEACHING—EFFECT OF UNIFORM FLOW FIELD

Fluorescence Recovery After Photobleaching (FRAP) is used to monitor the relaxation of concentration profiles after various imposed concentration fields. A theoretical analysis is conducted to quantify convective and diffusive transport and determine their contributions to fluorescence recovery in a perfused medium. Four different photobleach geometries—line, periodic pattern, uniform circular spot and Gaussian spot—are studied. It is shown that a spatially-averaged fluorescence profile (as would be the output of a photomultiplier) is inadequate in distinguishing convection from diffusion except in cases of large convection. In order to characterize both diffusive and convective effects, it is necessary to study the detailed concentration profile as a function of space and time.     

Assessing the impact of changing available multiple process plans of a job type on mean tardiness in job shop scheduling

This paper assesses the impact of changing the available multiple process plans of a job type in a production order on mean tardiness using simulation based genetic algorithm approach. A restart scheme as suggested in the literature is embedded into genetic algorithm in order to prevent premature convergence. An algorithm is developed to select a job type that becomes a candidate in order to change the available multiple process plans. Three case studies of varying sizes have been considered to assess the performance of job shop with an objective to minimise mean tardiness. Results indicate that by changing the available multiple process plans of a job type in a production order assists in reducing mean tardiness of a production order. In addition, selecting the best process plan among available multiple process plans on the basis of minimum total production time criterion for a job type does not yield optimal schedule.     

Effect of MoO3 Addition on the Grain Growth Kinetics of a Manganese Zinc Ferrite

The effect of MoO₃ addition on the grain growth and densification kinetics of a high permeability manganese zinc ferrite was studied. Grain growth in the presence of a small amount of MoO₃ occurs in two main stages characterized by a faster rate of grain growth accompanied by rapid densification and pore coalescence in the first stage, when the MoO₃ is present as a liquid phase along the grain boundaries, and comparatively slower rates of grain growth and densification than those for the basic composition in the second stage, when MoO₃ evaporates from the matrix. The activation energies for grain growth in these stages suggested that surface and volume diffusion mechanisms were operating in the first and second stages respectively.     

Finite-Element Analysis of Network Dilatation in Ion-Exchanged Glass Rods After Slicing

Finite-element analysis performed for the sliced glass rods exchanged by larger ions for various diffusion distances showed bulging of the cylindrical surface and concaving of the flat faces. Though these deformations result in the appearance of an apparent compression maximum at around 6 μm below the surface, they do not fully explain the presence of a compression maximum at 30- to 40-μm depths observed by many workers using photoelastic techniques. Introduction of plasticity in the exchanged layers renders the computed stress profile to resemble the experimental profiles, but is followed with a decrease in the computed depth of the compression maximum. Lowering of the glass transition temperature of the exchanged layers, which results in increased stress relaxation and the superimposition of varying thermal contraction of the layers, could account for the disagreements.     

Fretting fatigue crack initiation mechanism in Ti–6Al–4V

Fretting fatigue crack initiation in titanium alloy, Ti?6Al?4V, was investigated experimentally and analytically by using finite element analysis (FEA). Various types of fretting pads were used in order to determine the effects of contact geometries. Crack initiation location and crack angle orientation along the contact surface were determined by using microscopy. Finite element analysis was used in order to obtain stress state for the experimental conditions used during fretting fatigue tests. These were then used in order to investigate several critical plane based multiaxial fatigue parameters. These parameters were evaluated based on their ability to predict crack initiation location, crack orientation angle along the contact surface and the number of cycles to fretting fatigue crack initiation independent of geometry of fretting pad. These predictions were compared with their experimental counterparts in order to characterize the role of normal and shear stresses on fretting fatigue crack initiation. From these comparisons, fretting fatigue crack initiation mechanism in the tested titanium alloy appears to be governed by shear stress on the critical plane. However, normal stress on the critical plane also seems to play a role in fretting fatigue life. At present, the individual contributions/importance of shear and normal stresses in the crack initiation appears to be unclear; however, it is clear that any critical plane describing fretting fatigue crack initiation behaviour independent of geometry needs to include components of both shear and normal stresses.