The 13 Bit Lattice Gas Automata Model with Polyvelocity and Regular Hexagonal Grid

The 13 bit lattice gas automata model with polyvelocity and regular hexagonal grid has been introduced. By simulating typical flow pass cylinder, the correctness and validity of the model have been verified.     

Parallel Operating the 13-Bit Lattice Gas Automata Model

The parallel operation mechanism of 13 Bit lattice gas automata model, which can quickly compute and include more sites, is presented. Via coding and computing for particles of sites by bit, the parallel computing is achieved by transfering the particles propagation and collision into its backup and reloading. This mechanism can simulate correctly and validly some fluid motion with complex geometry boundary, such as flow through coke porous media. [WT5HZ]     

Analysis on the Diffusion Hazards of Unsteady Leakage of Gas Pipeline

Through analysis on the process of unsteady leakage of gas pipeline,the calculating model of unsteady leakage rate has been established.According to the variable characteristic of unsteady leakage ratio,based on the differential equation of on-flow diffusion,and combining the relevant original and boundary conditions,the diffusion model of unsteady leakage of gas pipeline has been established.Based on the practical application,all of the dangerous areas have been discussed and analyzed.The damaging and destroying areas have been calculated under definite conditions.This will provide safety standards and references for confirming and formulating the safety distance for the important buildings(school etc.) apart from the long high-pressure gas pipeline and main gas pipeline in city.At the same time,this will provide guarantee for reducing the dangerous degree,when accidents happened.     

Mathematical Model of Selective Catalytic Reaction of Nox in Reactor and Its Simulation

As the domestic technology of selective catalytic reduction(SCR) has not been mature.A assembled-parameter dynamic mathematical model is established for the primary chemistry reaction process in SCR reactor.The mass balance equation of the NH3 adsorption-desorption on the catalyzer surface and six gas components,and total energy balance equation in SCR reactor are set up respectively.A dynamic simulation model has developed by using MATLAB simulation tool.The steady calculation for model is carried on.Based on the established dynamic simulation model,two dynamic simulation experiments have been done,which include the simulation experiment of step disturbance about NOx concentration and temperature.The simulation results current is correctl.The analyzed results indicate that the established dynamic mathematical model for SCR reactor is credible,and prove that the simulation model is practical.     

Triaxial creep model and its stability analysis of gas containing coal 

Investigation on the creep property of coal containing gas is an effective means for understanding the mechanism of delay outburst of coal and gas in a coal mine. This paper conducts triaxial creep tests on the specimens of gas containing coal using a self made creep experimental apparatus to determine the creep law for coal containing gas. An improved triaxial creep model is developed for containing gas by coupling a Nishihara model with another visco elasto plastic body which can describe the deformation property of non Newtonian fluids. The parameter fittings are conducted based on the experimental dada.The present model is examined in terms to the results of triaxial creep tests in various stress level cases. The result shows that the proposed model for gas containing coal can properly represent the creep deformation at different creep stages, especially at the accelerating stage. The instability condition of the model for coal containing gas is also discussed according to stability theories of differential equation solution.     

Biological toxicity effect of CO in fire smoke

We investigate the effect of CO on the blood rheology parameters and blood gas composition. Experiments are conducted under isothermal toxicity gas concentration non radioactive conditions. We use an exposure box 0.8 m long, 0.5 m wide, and 0.5 m high. CO     

Quantitative analysis of photoacoustic spectroscopy detection for dissolvedgas in transformer oil based on least squares regression

Current solutions solve each component's gas concentration by multi equation inverse calculation, which has disadvantage of introducing parameter errors like noise, constant pool, etc. Based on the photoacoustic spectroscopy detection principle, a novel method for photoacoustic spectroscopy quantitative analysis is proposed using least square regression, and a quantitative analysis model is constructed. Using this method in inverse calculation of the gas concentration can avoid introducing parameter errors. The analysis model is verified by the experiment on the acetylene and methane dissolved in the transformer oil.     

Exploration on the Principle of ECMB

ECMB, which is developed by Amoco company in USA, has very prospective. On the basis of the study on adsorption characteristics of mixture gas in coal, the principle of ECMB has been explored. The order of adsorption capacities of coal for several gases is: CO 2>CH 4>N 2>H 2 when coal adsorbs gas. In 2 member mixture gases, adsorption capacities of coal for mixed gases, methane and carbon dioxide tally with Langmuir equation, but not does for nitrogen and hydrogen. The substance of the increasing drawing ratio of coal seam gas by using ECBM is decreasing adsorption amount of methane in coal by emptying the other gas or gases into coal seam. N 2 is better gas than CO 2 in the process of using ECMB.     

Perforation-mediated modified atmosphere packaging: Part I. Development of a mathematical model

A space-and-time dependent mathematical model describing perforation-mediated modified atmosphere packages was developed for respiring commodities. The model is based primarily on fundamental laws, with empirical relations used only when no other approach can be devised or when there is a significant advantage from using an empirical approach. The computational domain is divided into four subdomains: a part of the ambient storage environment; the perforation, allowing gas exchange between the package and the ambient; the commodity layer, inside the package; and the headspace above the commodity, but also contained in the package. The package walls are rigid and impermeable to gases but heat conducting. The commodity is treated as a homogenous porous medium with distributed sinks for oxygen consumption and distributed sources for carbon dioxide production due to commodity respiration. The commodity model also accounts for water vapour production due to transpiration and removal caused by possible condensation. The effects of commodity temperature and headspace gas composition on oxygen consumption and carbon dioxide production are accounted through a respiration model. The model permits the determination of the gas mixture velocity as the solution of Darcy's law in the commodity layer and the Navier–Stokes equations in the headspace, perforation, and surrounding ambient storage area. Transport of oxygen, carbon dioxide, water vapour and nitrogen is modelled based on Maxwell–Stefan equations coupled with the Navier–Stokes equations and Darcy's law. Solubility of carbon dioxide within the commodity has been included in the model. Commodity temperature and gas mixture temperature are modelled as solutions of the energy equation in the appropriate subdomains, coupled through transpiration, condensation, and convective heat transfer at the commodity surface.     

Study on Transport Equation and Numeric Simulation Equation of Gas Migration in Compressible Coal seam with Dual pore

The transport equation and numeric simulation equation of gas migration in compressible coal seam with dual pore have been built up. The distribution curves of gas pressure in coal seam and the attenuation curves of coal or drilling hole wall have been obtained according to solution of numeric simulation and similar theory.     

中国非CO2类温室气体减排潜力及其政策意涵

利用改进后的全球一般均衡环境模型（GTAP-E）及其6版非CO2类温室气体排放数据库,模拟了中国非CO2类温室气体减排潜力及其政策意涵。结果显示,现阶段,中国是世界上非CO2类温室气体排放最多的国家,2020年将会占到世界总排放的20%左右。其中,来自农业部门的非CO2类温室气体排放比重达到73%。未来10年,牛羊类、工业、服务行业的非CO2排放增速最快,且服务业的增速快于工业,并在2010年后超过工业排放。中国可以通过实施非CO2类温室气体减排政策,减轻二氧化碳减排的国际压力。虽然征收较高的碳税能够带来较高的非二氧化碳减排量,但是政策效率在高碳税和低碳税间差异不大。所以,在实施非二氧化碳减排碳税政策时,应该把碳税控制在一个较低的水平。     

Differential Employment Patterns for Citizens and Non‐Citizens in Science and Engineering in the United States: Minting and Competitive Effects

ABSTRACT The consequences of the heavy inflow of foreign talent for U.S. scientists and engineers over the period 1973‐1997 are examined using data from the Survey of Doctorate Recipients. Of particular interest is whether non‐citizens trained in the United States have displaced citizens from jobs in science and engineering (S&E). Using a novel adaptation of the shift‐share technique, it is shown that citizen S&E doctorates have fewer jobs in S&E and fewer academic jobs than their non‐citizen counterparts for two reasons: the citizen doctoral population has experienced slower growth than the non‐citizen doctoral population, and citizen S&E doctorates have been displaced. Whether the displacement observed was a voluntary response of citizens to the lure of better opportunities elsewhere or an involuntary response indicative of having been pushed out by foreign talent remains to be determined.     

一种检测荷载pGMCSF-SS质粒的减毒沙门氏菌数的方法学研究

以荷载pGMCSF-SS质粒的减毒沙门氏菌为参考菌,连续培养13h,间隔1h连续采样,用紫外分光光度计检测OD600值,同时用平板计数计算活菌数。根据所测数据,建立细菌对数与细菌浊度之间的直线回归数学模型,即Y=1.5568x 7.0944,R2=0.9543,并对相关关系进行了显著性检测r>r0.01,表明此回归方程可信度很高。为进一步检测该模型的可靠性,在培养时间内随机取样,检测OD600值,比较利用平板计数与回归方程所得细菌对数Y,二者差异不显著(p>0.05)。通过探讨细菌浊度与细菌计数之间的相关性建立的回归方程,可以有效地克服传统计数方法的不足,便于应用。     

Study on Methane Flow Regularity and Secondary Stress and Deformation of Coal Bady around Penetration Boreholes in Coal Seam

A new mathematical model for the coefficient of variable permeability affected by coal body, secondary stress & pressure in coalseam & a constitutive equation for gas migration are improved on the basis of the secondary stress & deformation of coal body around boreholes in coalseam. Using this model and equation,the gas flow field belongs to the 20102 experimental zone in BaiJiao coal Mine is computed & this verifies that the model & constitutive equation are both agreeable to practical results. Simultaneously, a comparison between the variable and constant permeabilities is carried out.     

Commuting distances to local non‐farm workplaces and out‐migration: The case of Northeast Thailand

The relationship between commuting distances and where people work has been studied for urban contexts in both developed countries and developing countries. However, few studies have examined the situation in rural areas, and none look at commuting distances to non‐farm workplaces in rural areas of developing countries. This paper investigates how commuting distance, and thus accessibility, to local non‐farm work influences non‐farm employment and out‐migration from rural villages in Northeast Thailand. The main issues examined are: (i) the distance that rural residents travel to work in local non‐farm jobs; and (ii) the influence that local non‐farm employment has on the number of outmigrants from rural villages. The study finds: (i) distance between villages and non‐farm work sites impact the number of villagers who are employed in regular wage work; (ii) beyond 20 km villagers are less likely to travel to non‐farm employment using their own means of transportation; and (iii) employment in regular wage work decreases outmigration. The findings from this study contribute to the debates over the drivers of rural out‐migration, rural livelihood changes, and agrarian changes that are taking place in Southeast Asia.     

Mathematical Model of Oxygen Blast Furnace with Preheating Gas Injection into Upper Shaft

An One-dimensional mathematical model,based on oxygen blast furnace with preheating gas injection into upper shaft,has been developed to describe the variation of innerdiameter of blast furnace,13 chemical reactions,the heat losses through the furnace wall,the heatexchange and pressure losses between gas phase and solid phase.The characters of oxygen blastfurnace are discussed,The simulated results indicate that the tem perature of burden in creasesthroughout the upper shaft with the incrcasement of the flow and the temperature of preheating gasinjected,and that the effect of the heating-up of burden is not so large when the com positions ofpreheatin8 gas injeetion are changed.The model is contributed to obtain a deeper understanding ofthe oxygen blast furnace process.     

An Unsteady Flow Analysis in Gas Transmission Pipeline Based on Theory of Functional Analysis

Branch -like pipeline is a common structure in gas transmission pipeline. In the light of the constituent properties of natural gas branch - like pipeline system, the system can be divided into fundamental constituent units. This paper presents a realistic unsteady flow model consisting of simple models of pipeline units and connecting conditions, boundary conditions and initial condition associated with units by using system analysis method. The solutions in wide sense are obtained by theory of functional analysis and operator series method, Such a method has the properties of both analytical solution and numerical solution methods. When the divided pipeline unit is larger, an intuitive approximate analytical solution may be obtained; while the one is smaller, a more accurate numerical solution may be acquired. Based on this, a general computer program has been developed for this model and solutions have been used successfully in a local natural gas transmission network in Sichuan. It is proved that the model and algorithm proposed in this paper are of the advantages of convenient calculation, high precision, time saving and wide application range by way of analysis and application.     

Numerical Modeling of Ice Slurry Flow Pressure Drop in Horizontal Pipes

To predict pressure drop of ice slurry flow in horizontal pipes, a mixture CFD model was applied to simulate the two-phase flow without considering ice melting. Based on the specific flow features, the Newtonian and non-Newtonian rheological expressions were employed respectively. It is found that in high speed the Thomas viscosity equation behaves well in representing the mixture fluid viscosity; whereas in low speed the Bingham model is more suitable for describing the mixture fluid rheology. Compared with the published pressure drop correlations, the current numerical model can involve with various factors and has a good balance between precision and suitability. The results of numerical model are in excellent agreement with the experimental data and the relative errors are limited to ±15%.     

Influence of Humidity Distribution on Cross Diffusion Extent in Building Space

The influencing relationship equation of humidity distribution on the characteristics and extent of cross diffusion was proposed based on the non equilibrium thermodynamic theory. With the parameters of temperature, humidity and contaminant gas concentration, a further study on the relationship was employed. It was showed that the temperature grads and the contaminant gas mass grads were less than zero when the humidity grads and additional diffusion coefficient were both positive/negative, otherwise the two grads were more than zero. Moreover, the higher the initial temperature and contaminant gas concentration were, the greater the absolute values of temperature grads and contaminant gas mass grads were, with the same humidity grads and additional diffusion coefficient. Whereas the influence of initial temperature was limited, and that of initial contaminant gas concentration was obvious.     

吉林省西部生态安全态势与土地利用的耦合分析

依据人类与生态环境系统的相互作用,建立了压力-反馈-调控的概念模型,并基于GIS和RS,采用栅格运算的方法,运用复合模型对吉林省西部2000年生态环境安全态势进行了研究。结果表明：吉林省西部大部分地区处于安全状况,且东部安全状况好于西部,预警状况及不安全状况的区域集中分布在中部和西部。十个县市中,绝对安全状态比例极小,安全状态区域所占比例最大的县是乾安,最小的是大安。预警状态区域所占比例最大的是洮南,已达到了县域面积的43.08%,最小的是乾安,仅占1.56%。通榆、镇赉和大安处于不安全状态区域的面积已达到了10%以上,是吉林省西部生态环境需要重点治理的区域。吉林省2000年生态安全态势与土地利用的耦合分析表明,以农为主的区域是农牧交错带中相对稳定的区域,以牧为主的区域受到的破坏程度最大,农牧相当的区域属于最脆弱的地区。虽然根据Constanz的生态价值理论,草地的生态价值比较高,但由于研究区草地多属于低覆盖度,当受到外界干扰较大时,系统就表现得极不稳定。