Grid data management based on dataspace

To manipulate the heterogeneous and distributed data better in the data grid,a dataspace management framework for grid data is proposed based on in-depth research on grid technology.Combining technologies in dataspace management,such as data model iDM and query language iTrails,with the grid data access middleware OGSA-DAI,a grid dataspace management prototype system is built,in which tasks like data accessing,Abstraction,indexing,services management and answer-query are implemented by the OGSA-DAI workflows.Experimental results show that it is feasible to apply a dataspace management mechanism to the grid environment.Dataspace meets the grid data management needs in that it hides the heterogeneity and distribution of grid data and can adapt to the dynamic characteristics of the grid.The proposed grid dataspace management provides a new method for grid data management.

Ventilation control of tunnel drilling dust based on numerical simulation

In order to control the dust pollution produced by air leg rock drill in the trolley area during the excavation of long-distance single ended tunnel,the full-scale physical model of working face was established by using FLUENT software,and the numerical simulation analysis of tunnel drilling ventilation and dust removal parameters was carried out.The results show that it is difficult to control the dust pollution of the face by conventional ventilation,and the drilling dust is distributed in the range of 10 m from the face;after the introduction of the long pressure and short suction ventilation scheme,when the ratio of compressed air volume to exhaust air volume is 0.72,the height of the pressure fan is 2.5 m,the distance between the pressure fan and the palm face is 20 m,and the exhaust fan is 12 m away from the palm,the dust concentration control efficiency of the working face is increased by about 60%.Therefore,in the similar long-distance single head tunnel construction,it is appropriate to adopt the dust removal method of long-distance short suction and exhaust fan to ensure the working environment.

Removal of PCDDs/Fs from municipal solid waste incineration by entrained-flow adsorption technology

Entrained flow adsorption using activated carbon as the adsorbent is widely adopted for PCDDs/Fs-abatement in municipal solid waste incineration (MSWI) process. The effects of operating parameters including flue gas temperature, feeding rate of activated carbon, polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDDs/Fs) concentration at the inlet of the air pollution control device (APCD), filter materials, pressure drop on PCDDs/Fs removal efficiency are reviewed and commented upon in this paper. Evaluation on the various mechanistic models for entrained flow adsorption is carried out based on the computational simulation in terms of the actual operating condition and theoretical analysis. Finally, an advancement of en- trained flow adsorption in combination of dual bag filter is introduced.

An integrated approach to study of strata behaviour and gas flow dynamics and its application

This paper presents an advanced and integrated research approach to longwall mining-induced strata move- ment, stress changes, fractures, and gas flow dynamics with actual examples of its application from recent studies for coextraction of coal and methane development at Huainan Mining Group in China, in a deep and multi-seam mining environment. The advanced approach takes advantage of the latest techniques in Australia for mine scale geotechnical characterisation, field measurement, monitoring and numerical modelling. Key techniques described in this paper include coal mine site 3D geotechnical characterisation methods, surface deep downhole multi-point extensometers and piezometers for overburden displacement and pore pressure measurements during mining, tracer gas tests for goal gas flow patterns, and advanced numerical modelling codes for coupled coal mine strata, water and gas simulations, and longwall goaf gas ttow investigations. This integrated approach has resulted in significant insights into the complex dynamic imeraction between strata, groundwater, and gas during mining at Huainan Mining Group in recent years. Based on the lindings from the extensive field monitoring and numerical modelling studies, a three-dimensional annular-shaped over-lying zone along the perimeter of the longwall panel was identified for optimal methane drainage during mining.

Analysis and application in controlling surrounding rock of support reinforced roadway in gob-side entry with fully mechanized mining

In order to optimize gob-side entry in fully-mechanized working face in moderate-thick-coal seams, we adopt a new attempt to pack roadside by pumping ordinary concrete, which is very important for the development of gob-side entry technology. The concrete has a long initial setting time and a low initial strength. So it is difficult to control the surrounding rock. In this paper, we analyze the effect of using roadside cable to reinforce supporting in gob-side entry surrounding rock controlling based on elas-tic-plastic and material mechanics knowledge. And then we propose a scheme that cable is used to reinforce roadside supporting and a single hydraulic prop is used as the temporary supporting in gob side. Using the numerical simulation software FLAC2D, we numerically simulated supporting scheme. Results of both the 2D modeling and the industrial test on No.3117 face in Jingang Mine prove that the scheme is feasible. The results show that the technology of protecting the roadway in gob-entry retained efficiently make up the deficiency of roadside packing with ordinary concrete, effectively control the roof strata and acquire a good result of retaining roadway.

Numerical Simulation of Coal Floor Fault Activation Influenced by Mining

By means of the numerical simulation software ANSYS, the activation regularity of coal floor faults caused by mining is simulated. The results indicate that the variation in horizontal, vertical and shear stresses, as well as the horizontal and vertical displacements in the upper and the lower fault blocks at the workface are almost identical. Influ- enced by mining of the floor rock, there are stress releasing and stress rising areas at the upper part and at the footwall of the fault. The distribution of stress is influenced by the fault so that the stress isolines are staggered by the fault face and the stress is focused on the rock seam around the two ends of the fault. But the influence in fault activation on the upper or the lower fault blocks of the workface is markedly different. When the workface is on the footwall of the fault, there is a horizontal tension stress area on the upper part of the fault; when the workface is on the upper part of the fault, it has a horizontal compressive stress area on the lower fault block. When the workface is at the lower fault block, the maximum vertical displacement is 5 times larger then when the workface is on the upper fault block, which greatly in- creases the chance of a fatal inrush of water from the coal floor.

Numerical simulation study on the thermal environment in heading face

Based on κ-ε turbulence model, the distributions of the velocity field, tempera- ture field, thermal comfort index, PMV-PPD （Predicted Mean Vote-Predicted Percentage Dissatisfied）, and air quality index, mean age of air were obtained of Zhouyuanshan Coal Mine in -650 m level of a heading face by CFD（Computational Fluid Dynamics）software, Airpak 2.0. Moreover, the human thermal comfort and the air quality of the heading face were analyzed with PMV-PPD and mean age of air indices, which received an intuitive visualization and accurate evaluation results. In order to create a safe, comfortable, and economical underground operating environment, a scientific, rational, and comprehensive prediction and evaluation needed to provide a theoretical and technical basis for coal mine ventilation, cooling, heat harm treatment, and prevention. Meanwhile, from the human thermal comfort and air quality to research the underground environment, it embodied the concept of being human oriented.

Effects of working parameters on gasoline engine exergy balance

To improve the energy utilization efficiency of internal combustion （IC） engine, exergy analysis was conducted on a passenger car gasoline engine. According to the thermodynamic theory of IC engine, in-cylinder exergy balance model was built. The working processes of gasoline engine were simulated by using the GT-power. In this way, the required parameters were calculated and then gasoline engine exergy balance was obtained by programming on computer. On this basis, the influences of various parameters on exergy balance were analyzed. Results show that, the proportions of various forms of exergy in gasoline engine from high to low are irreversible loss, effective work, exhaust gas exergy and heat transfer exergy. Effective exergy proportion fluctuates with cylinder volumetric efficiency at full load, while it always increases with break mean effective pressure （BMEP） at part load. Exhaust gas exergy proportion is more sensitive to speed, and it increases with speed increasing except at the highest speed. The lower proportion of heat transfer exergy appears at high speed and high load. Irreversible loss is mainly influenced by load. At part load, higher BMEP results in lower proportion of irreversible loss; at full load, the proportion of irreversible loss changes little except at the highest speed.

Measurement and Prediction of Vapor Pressure for H20 ＋ CHaOH] C2HsOH ＋ [BMIM][DBP] Ternary Working Fluids

The ionic liquid, 1-butyl-3-methylimidazolium dibutylphosphate ([BMIM][DBP]) was prepared and the vapor pressures of three set of binary solutions H2O(1)/CH3OH(1)/C2H5OH(1) + [BMIM][DBP](2) were measured at different temperature and in the ILs mole fraction range from 0.1 to 0.6 with a static equilibrium apparatus. The measured vapor pressures were correlated with Non-Random Two Liquid (NRTL) activity coefficient model and the average relative deviations (ARD) between experimental and correlated vapor pressures for these binary solutions were 3.19%, 2.42% and 2.95%, respectively. Then, the vapor pressures of two set of ternary solutions H2O(1) + CH3OH(2)/C2H5OH(2) + [BMIM][DBP](3) were measured with an inclined boiling apparatus and further predicted with NRTL activity coefficient model based on the binary interaction parameters coming from fitting the vapor pressures of the binary solutions. The results indicated that the ternary solutions containing [BMIM][DBP] were shown a strong negative deviation from Raoult's Law when the mole fraction of [BMIM][DBP] was larger than 0.2, which meant that ternary solutions could absorb the refrigerant vapors at the same or below solution temperature. Meanwhile, the average relative deviations between experimental and predicted vapor pressures for ternary solutions were 2.92% and 3.06%, respectively. Consequently, the NRTL active coefficient model used for non-electrolyte solutions was still valid for predicting vapor-liquid equilibrium of binary or ternary solutions containing ILs.

Numerical simulation and model of control-efficiency of thermal crown of work rolls in cold rolling

Aiming at accuracy control of the thermal crown of work rolls in cold rolling,new parameters such as regulation domain and control-efficiency factors were proposed and a numerical analysis model of the thermal crown of work rolls was established using finite difference method to study roll's thermal deformation.Based on simulation results,the influences of control-efficiency factors on thermal crown are presented and the thermal crown of work rolls is analyzed after taking sub-cooling of sprinkling beam into consideration.It has been found that the control-efficiency factor of any position on the roll's surface is linear function of the temperature and the control ability of water temperature is stronger than other control parameters.In addition,the verification of the model has been carried out based on the producing technology data in some factories and the numerical simulation results coincide well with the experimental data.Therefore,this work has important value for on-line control of roll's crown in cold rolling.

Effect of working parameters on performance characteristics of hydrostatic turntable by using FSI-thermal model

Effects of working parameters on performance characteristics of hydrostatic turntable are researched by applying the fluid-structure-thermal coupled model.Fluid-structure interaction(FSI)technique and computational fluid dynamics(CFD)method are both employed by this new model,and thermal effects are also considered.Hydrostatic turntable systems with a series of oil supply pressures,various oil recess depth and several surface roughness parameters are studied.Performance parameters,such as turntable displacement,system flow rate,temperature rise of lubrication,stiffness and damping coefficients,are derived from different working parameters(rotational speed of turntable and exerted external load)of the hydrostatic turntable.Numerical results obtained from this FSI-thermal model are presented and discussed,and theoretical predictions are in good agreement with the experimental data.Therefore,this developed model is a very useful tool for studying hydrostatic turntables.The calculation results show that in order to obtain better performance,a rational selection of the design parameters is essential.

Key technology study on pillar mining under the system of room and pillar mining

Taken taifeng coal mine in Mongolia for example, discussed the stability and controllability about advance pillars which locate at the front of working face and makes simulation on pillar with the software UDEC3.1. The failure styles of advance pillars are shear failure and compression failure through analyzing the stability of advance pillars. The paper concludes that can protect advance pillars from shear failure by controlling coefficient of volumetric expansion of mining field rock and supports＇ working resistance and can also protect it from compression failure by advance supporting, increasing setting pressure and working resistance. Two advance pillars are influenced and the main failure form is compression failure through the numerical simulation.

Numerical and Experimental Investigation of an Elliptical Paraboloid Shell Model

For practical engineering purpose, a new flat shell element baptized （ACM_Q4SBE1） is presented in this paper. The formulated element can be used for the analysis of thin shell structures; no matter how the geometrical shape might be. Tests on standard problems have been examined. Since, the analysis of thin shell structures has generally been purely carried out on a theoretical basis; it is of importance to present some experimental results of an elliptical paraboloid under uniformly distributed load pressure. The results obtained from both numerical and experimental work are presented.

Numerical simulation of dust distribution at a fully mechanized face under the isolation effect of an air curtain

At a fully mechanized working face of a coal mine as prototype,we investigated,by simulation,the flow field and dust distribution during the process of its isolation by a curtain of air,using the CFD software, Fluent.The results show that the air curtain installed on the shearer can effectively prevent the dust （especially the respirable dust）from diffusing into the work area of the operator,reducing the dust concentration on the side of the operator and greatly improving his working environment.The field application of the air curtain shows that the dust-isolation effect of an air curtain is quite noticeable.The isolation efficiency for respiratory dust is over 70%and,as well,it has good dust-isolation effect for nonrespiratory dust.The air curtain is a useful way to resolve the problem of dust-isolation at a fully mechanized working face.It has a practical background elsewhere with more extensive applications.

Determination of coal mine mechanization using fuzzy logic

Two of the most important tasks in coal mines are to improve efficiency and to increase production besides keeping safety constantly in mind.In order to obtain these goals,mine mechanization is required.Mine mechanization needs high levels of investment and should therefore be studied carefully before final decisions about mechanization are made.When analysizing the potential for mechanization the following,rather imprecise,factors should be considered:seam inclination and thickness,geological disturbances,seam floor conditions,roof conditions,water at the working face and the extension of seams.In our study we have used fuzzy logic,membership functions and created fuzzy rule-based methods and to considered the ultimate objective:mechanization of mining.As a case study,the mechanization of the Takht coal seams in Iran was investigated.The results show a high potential for mechanization in most of the Takht coal seams.

Analysis of Noise at Coal Face by Fully-Mechanized Coal Winning Technology

The noise level of coal face by full-mechanized coal winning technology was measured in a coal mine. And then it was analyzed and evaluated using environment science, ergonomics and fussy mathematics analysis. Basis of the statistics and analysis of the measured noise level some measures, such as applying the new materials and improving the construction of the equipment, were carried out. The resuts show that they can reduce the noise level, improve the working environment and enhance the work efficiency.

THE THEORETICAL MODEL FOR PREDICTING CIRCULATION VELOCITY OF HYDRAULIC BRAKE

By rational hypothesis of fluid flow pattern, applied the law of conservation of energy and integrated the laboratory test results, finished the prediction by the theoretical model of cir-culation velocity of hydraulic brake which is important parameter. Thus provide the theoritical basis for hydraulic brake of bblt conveyor whose research has just been started.

Pressure performance improvement by dual-mode control in digital pump/motor

Due to the advantages of low cost,fast response and pollution resistance,digital hydraulic pump/motor can replace conventional variable hydraulic pump/motor in many application fields.However,digital hydraulic components produce large hydraulic impact at variable moments,which will shorten the service life of mechanical components.Through the simulation analysis of the variable process of digital pump/motor,it is found that the discontinuous flow caused by displacement step changes is the fundamental cause of hydraulic impact.The data analysis results of experimental tests are in good agreement with the simulation analysis results.In view of hydraulic secondary components,a variable control method based on dual-mode operating characteristics is proposed.The TOPSIS algorithm is used to give comprehensive evaluation of the displacement control results after this method.The results show that the control quality of digital pump/motor after adopting the control method has been effectively improved,with an average improvement of about 40%.

Analysis on characteristics of damaged field of surrounding rock and face of FMTC

Numerical simulation-FLAC^(3D) and equivalent material simulation were carried out to analyze the damaged patterns and lows, distribution of plastic width of face, and surrounding rock of FMTC during the advance of work face with different thick coal seams based on engineering geology and exploitation technology of 1151(3) fully mechanized top-coal caving (FMTC) face in Xieqiao Colliery.The results show that there is damage,and the destruction characteristics of surrounding rock and coal mass are different obviously in asymmetric exploitation layout.The damaged zone in surrounding rock and the coal of the return airway is larger than that of the intake airway.Moreover, the retained coal pillars are all damaged by tension and shear fracture, and plastic zone in coal mass in the dip direction ahead of Face is nonuniform.There are large damage zones in roof and floor strata, surrounding rock, and coal of return and intake airways near work face.The damaged zone in the upper part of Face is larger than that in middle and lower parts.The fruits of this paper are of guiding significance for engineering practices, such as support design and choice, roadway supporting and maintaining, rock pressure control of FMTC face, etc.

Human Resource Management in Operational Level of Generation Y at Northern Region Industrial Estate Lamphun, Thailand

The generation Y is a growing group of young people among the general workforce, having different behaviors and motivators at work. To study effective motivating factors for this group of employees can even show some interesting factors of Y-generation employees＇ value, such as high value of manager flexibility and sharing similar values with the companies they work for. The primary aim of this study is to understand the relationship of Y-generation employee＇s work motivation between operational behaviors and work and organization interests. There are several companies with a number of young employees at Northern Region Industrial Estate Lamphun, Thailand. These companies obviously need to focus on the requirements of Y-generation employees. The study population consisted of Y-generation employees of Northern Region Industrial Estate, Lamphun in which 410 are selected by simple random sampling for the research. The questionnaires were analyzed using LISREL. Two types of data analysis have been performed which are descriptive and Structure Equation Model （SEM）. The research findings indicate that having behavior in the right direction should focus on motivation factors. Motivation to get work and organization interests should focus on hygiene factors. There is a correlation between the operational level of generation Y employees work motivation and their operational behaviors and work and organization interests. The relationship between them clearly is defined in fact finding for determining the human resource management policies.