Study on burden pile profile prediction model for COREX-3000 melter gasifier

The distribution of reducing gas in melter gasifier of COREX-3000 directly influences gas utilization and burden descent.The charging of burden is a main method of regulating gas flow distribution.In order to reveal the burden distribution process,a mathematical model of forecasting the burden pile profile is established based on the impact position,angle of repose and the mass conservation of burden.The impact position of burden is determined by analyzing the material flow trajectory and force during charging process.Based on the mathematical model,an extended burden pile profile prediction software of COREX-3000 melter gasifier is developed by combining mathematic knowledge and computer technology.Using this software,the burden trajectory,the impact position and the burden pile profile under various operations of the coal-gimbal distributor and the DRI-flap distributor can be easily obtained,which can provide reference data for adjusting the charging operation in practice.     

Clogging mechanical model and its application in gas extraction borehole

A clogging segment mechanical model is established on gas extraction horizontal borehole. Based on the air pressure extremes pmax of the construction site, we solve the corresponding critical clogging length L0 and find clogging will occur when L> L0. With the clogging segment mechanical model, we analyze the calculation method of the retreat drilling rod resistance in borehole. The influence rule of clogging length and air supplying system pressure on retreat drilling rod resistance is analyzed. Analysis results show that the main reason for difficult drilling clogging and retreat drilling rod is the higher pressure in borehole clogging segment. The retreat drilling rod resistance is especially sensitive to the change of air supplying system; therefore, the effective method of reducing the retreat drilling rod resistance is reducing the air supplying system pressure in borehole. The drilling construction status in Jiulishan coal mine is analyzed by using the clogging segment mechanical model, and three technical measures are put forward, including increasing slagging space, reducing slagging resistance and increasing drilling rod strength. When the improving measures are adopted, the pipe-sticking phenomena decreases, the drilling rod broken phenomenon are averted and the drilling efficiency increases by 17%.     

Experimental Analysis of Rotational Behavior of Timber Beam-column Connection of Ancient Tibetan Architecture

Static experiment was carried out to study rotation behavior of timber beam-column connection. The influence of length of Gongmu and position of dowel on the initial rotational stiffness of the joint was analyzed. Rules of stiffness degradation under cyclic loading were studied as well. The results show that: the moment-rotation curve of typical timber beam-column connection can be simplified as bilinear model; the initial rotational stiffness of the joint is enhanced with the increase of the length of Gongmu, and it is decreased with the inward movement of dowel; under the same conditions, the influence of the inward movement of Gongmu-beam dowel on the initial rotational stiffness of the joint is smaller than that of Dianmu-Gongmu dowel; and stiffness degrades under cyclic loading and there exists obvious transition phenomenon.     

Mathematical Model of Control Cooling for Screw Rod After Rolling

The on line hot treatment can not only boost the strength but also gain lower cost. It is usually called tempcore which was developed greatly these years. The process of tempcor art is introduced and the core subject mathematical models is studied. According to the heating exchanging property of screw rod in cooling after rolling.Two mathematical models including beginning cooling model and cooling water amount model are obtained by analysing, deducing theoretically and simplifying mathematically. Its structure is simple and practiced .The parameter of model is obtained from measuring data of work site. It is able to suite the change of work site, so it can be used in practiced controlling.     

Developing of Auto-control Position System in Push-coke Machine

The auto controlling based on PLC system realized the identifying of coking number and the accurate position.In this system the identifying of coking number was reached with the schematic binary system of PLC and the assistant of proximity sensor.With RS485 ,the digital was used for transducer controlling port which drive the motor and the high speed counter, AD61, was used for feedback adjusting the offset.The discrete digital increasing PID control algorithm compensating the position errors is discussed to arrive at the accuracy auto position.With the module ,RS485,we realize the serial communication and the report forms managing between the PLLC system and the computer.The technique can achieve the object of automatic control accuracy in practices.     

Prediction Model of Intermixing Slab Length During Continuous Casting Grade Transition Process

In order to increase decision accuracy of the intermixing slab length and position, and decrease the slabs which are offgraded or scrapped. Water model experiments were conducted to simulate the continuous casting grade transition process of No. 2 continuous caster at Bao Steel. The dimensionless concentration profiles along slab length with different continuous casting conditions were measured. Based on the profiles a mathematical model was developed to predict the final composition distributions and length of intermixing slab. Comparison of predicted dimensionless concentration profile with plant data shows that the precision of the model is considerably satisfied to meet the need of steel grade transition evaluation.     

Micromechanis Analysis of Load-transfer Mechanism is Single-fibre Fregmentation Test

The paper presented a new micomechanics load-transfer model for single-fibre fragmentation test. The interfacial shear streength and the crack will develop along the interface. The fibre stochastic strength distribution was modelled by a two-parameter Wibull distribution. The influence of the interfacial bonding strength and fibre axial-tensile strength on stress states in components of composites was discussed. The interfacial state during the fragmentation process may be one of following three states: 1) fully bonding; 2) partial bonding; 3) fully debonding; according to the fibre axialtensile strength and interfacial properties (including interfacial bounding shear strength, interfacial friction coefficient and matrix radial pressure) after elastic constants and geometrical parameters of composites phases are given. The necessary conditions for these three states were discussed- Finally, a suitable definition of the critical fibre length was given and the critical length was constrouted by two parts :debonding fibre length and bonding fibre length.     

Improvement upon the Formulas for Solar Position in Analysis of Sunlight Distribution in Buildings

The application of existing formulas to determine solar altitude and azimuth angles is inconvenient and inadequate. To improve the existing formulas, a new timing system named the Radiation Calendar was established. In this system the angles' ranges were redefined, making the angles calculated from the improved formulas single valued and varying with hour angle. Representative curves of solar altitude and azimuth angles varying with hour angle were plotted. The mathematical distinctions of these curves astronomically and geographically describe some rules of solar position varying with time, which proves the validity and generality of the improved formulas. The results calculated using the improved formulas show simply and clearly the daily and annual variation of solar altitude and azimuth angles, which are valuable in the work of sunlight distribution analysis related to the design of buildings, air conditioning systems and structures.     

Analysis of the Fiber Quality of Upland Cotton in China from 2005 to 2007

Upper-half-mean length (Len),uniformity index (UI),breaking tenacity (Str),and mieronaire value (Mic) are the key quality parameters of cotton fiber.In this study,182 upland cotton varieties examined and approved by The National or Provincial Committees for the Examination and Approval of Crop from 2005 to 2007 were selected as materials.These varieties were the most popular varieties planted in China.The result indicated that the distribution of fiber length was very limited.The fiber length of 145 varieties was concentrated from 28 mm to 30 mm,which was nearly 80% of the varieties.     

Bearing capacity of composite columns reinforced by concrete filled steel tube

In this study, nine simplified short composite columns consisting of core CFST (concrete filled steel tube) of different diameters and outer reinforced concrete were constructed to study their compressive performance under axial or eccentric compression. The failure mode is characterized by the crush of the outer concrete. The bearing capacity increases at first and then decreases with further increase of the position coefficient. It can be concluded that position coefficient is an important structural parameter that has considerable influences on the ultimate bearing capacity of the composite columns. The outer concrete, steel tubes and longitudinal reinforcement are found to work in a cooperative manner under axial or eccentric compression when the position coefficient is about 0.5. An improved bearing capacity algorithm that takes the position coefficient into account has been proposed based on the experimental and simulation results and current technical specification in China. It has been proven to be precise and safe.     

Size Effect of Bending Strength of Chinese Larch Lumber

The relationship between the bending strength and the size of Chinese larch visually-graded lumber was investigated. 1,961 pieces of lumber with three different widths were divided into two groups of high visual grades and low visual grades. The ultimate bending strength was tested under test spans of 18 times test depths. The combined length and width size effects of 5th percentile of bending strength were estimated by the slope method and the parametric method. Using the slope method, the estimated effect parameters of H and L were 0.19 and 0.23 for the 5th percentile.     

Study of Modern Applied Technology for Design and Manufacture of Spiral Bevel and Hypoid Gears

A new method of computing the cutter specifications and machine settings for the manufacture of spiral bevel and hypoid gears is studied. And a software system which includes the program models of new and old methods is developed. The system can perform the computations such as blank dimensions,cutting and grinding settings,tooth contact analysis and under cut check of SGM,SFM,SGT,SFT,HGM,HFM,HGT,HFT cutting methods. The new method can allow the user to give the position and length of contact pattern,the direction of contact path and the relative anglar acceleration. The system can be easily operated.     

Nondestructive Test of Surface Defect of Hot Slabs Based on Machine Vision at High Temperature State

Aimed at the problem of online detection of continuous slabs surface defect at high temperature, The CCD shutter control model was established using machine vision technology and equipment at high temperature states. The default clustering algorithm was provided. The CCD imaging equipment with dual cool modes of water and air was selected to ensure continuous work at high temperature conditions. The slab width of 3 000 mm can be detected, and the system can effectively restrain the influence of noise signals brought by oscillation marks on the surface of slabs and realize monitoring and clustering of the slab surface default.     

Model test and numerical simulation of tailing dam safety forecasting

To explore the safety of dam in future operation, we study the stability of Xiaodae tailing dam, Sichuan Province, P. R. China, via model testing and numerical simulation according to preliminary dam design information. The results show that the deposited beach length initially is shorter and the depth of the saturation line in a tailing dam is relative shallow. The length of deposited beach is relatively long in the middle and later periods, and the saturation line maintains a relatively stable position. The numerical simulation shows that horizontal dam displacement is 0.68 m and the greatest vertical displacement is 3.44 m at the dam vertices when the dam reaches the designed elevation. Meanwhile, the dam possesses normal stability. The largest shear stress in flooding exceeds that of normal conditions and the dam saturation line is higher. Unless measures are taken, these conditions will influence dam security.     

Shaking Table Test on Soil pile Interaction of Large Aqueducts

Shaking table tests were carried out for Minghe River Aqueduct in South to North Water Diversion Central Line Project.Based on the data of the tests,dynamic response characteristics were analyzed for two different design alternatives, which were equal length pile foundation and Unequal length pile foundation.The effect was initially estimated on the dynamic response of pile foundation when circle spray reinforcement was used.And wood rubber model box was objectively evaluated in the tests.It is shown that unequal length pile design alternative is more appropriate than equal length pile.Moreover, circle spray reinforcement can improve the behavior of dynamic response of pile foundation and wood rubber model box is rational and feasible.     

Analysis and Comparison of Submersible Pumps Used in Construction

In this paper the common submersible pump and the foul water submersible pump were compared with the submersible sand pump. Then, the principle and structure features of the submersible sand pump were introduced. The hydraulic pattern of submersible sand pump was designed according to two kinds of fluid theory. There is an air room at submersible sand pump added. The motor axle of submersible sand pump was extended from the air room. Inside the motor there is a small reservoir and the drop of water can be collected. The working condition of submersible sand pump was improved. The submersible sand pump can work longer time.     

Stress Corrosion of Concrete Exposed to the Action of Freezing-thawing Cycles

Through the method of accelerated freezing-thawing and room-temperature corrosion, the stress corrosion of three kinds of concretes subjected to 5.0%MgSO4(in mass)solution was studied. The considered concretes include High Strength Concrete(HSC), High-Volume Mineral Admixture Concrete(HVMAC) and High Durable Concrete(HDC) added with high-volume mineral admixture, air-entraining agent, superplasticizer, fibers and expansion agent. The results showed that the relative dynamic elastic modulus of concrete went through strengthen and deterioration stages subjected to stress corrosion, whether the room temperature or freezing and thawing conditions. The length of time of these two stages are closely related with the experimental temperature. Freezing and thawing action significantly accelerated the process of sulphate stress corrosion damage. Under the action of freezing and thawing, stress corrosion strengthening the period length of HSC shorter 96%, deterioration section of the length of time shorter 88%, compared with the length of time at the corresponding room temperature. Deterioration section of the length of time of HVMAC is reduced by 98%, while the HDC reduced by 71%. The effect of freezing and thawing, HDC freezing-thawing cycles when the stress corrosion damage occurred were longer 1.5 times and 13 times than the HSC and HVMAC. Thus in the cold regions, HDC showed more resistance to sulfate stress corrosion.     

Experimental Analysis of Extension Length of Shape Steel in SRC-RC Transfer Column

Seismic performance of SRC-RC transfer column was analyzed based on experiment of 12 specimens of transfer columns and 1 RC specimen under low cyclic reversed loading, which mainly focused on the extension length of shape steel. Analysis and comparison on skeleton curves of specimens was carried out. Analysis was completed for ductility, bearing capacity, energy dissipation capacity and degeneration ratio of strength. Displacement ductility changes with the increase of extension length of shape steel, enhancing at first, then reducing, and reaching peak value when extension length is close to three fifths of column height. Extension length of shape steel has little effect on bearing capacity. Energy dissipation capacity of transfer columns has relationship with many factors. Three fifths of column height is rational for extension length of shape steel, and specimens have not only advanced performance of energy dissipation but also good stability of stiffness and strength in this condition. The bond performance between concrete and shape steel decreases with the increment of extension length of shape steel, and hence stability of strength decreases.     

Seismic Behavior of Asymmetric Building under Pushover Analysis

Pushover analysis is a tool to study the inelastic behavior of structures under strong seismic action. The 3D-pushover analysis was performed to analyze the inelastic lateral-torsional coupled response of multistory asymmetric structures. The symmetric frame and frame-wall systems were studied in this paper, and the capability curve of the top displacement and base shear,the story drift and the position of rotation center were compared with reference to corresponding symmetric structures. The characters of inelastic response of multistory asymmetric structures were found. The conclusion provides reference for performance-based seismic design of asymmetric structures.     

Mechanics Characteristis Andlysis and Improvement of Film Dynamie Sthess Modulaten

The kinematical principle and mechanical characteristic of the cell membrane stress modulator are analyzed, which is a key equipment of the external cell bringing up experimental system. A designing project of the experimental system is put forward based on position measurement and controlling modulating region. It validates that the design can improve the mechanical characteristic of the device. At the same time, the device can work smoothly, the life time of its correlative parts can be increased, and the power waste of the system can be reduced.