浅析胶带机均匀分料技术在块煤筛分系统中的应用

对神华黄骅港务公司块煤筛分系统分料不均的问题进行了分析,并对胶带机均匀分料技术在块煤筛分系统中的应用进行了研究,结合实际应用案例,探讨胶带机均匀分料技术的改造方案。此项技术实现了对物料的均匀分料,为设备安全运行提供了可靠保障,大幅节约了维修成本,提高了生产效率。

浅析皮带机均匀分料技术在块煤筛分系统中的应用

在港口运输行业皮带机系统迅猛发展的同时,如何确保皮带机均匀分料和设备安全、平稳运行,正成为一个新的课题。主要对神华黄骅港务公司块煤筛分系统分料不均的问题进行了分析,并对皮带机均匀分料技术在块煤筛分系统中的应用进行了研究,结合实际应用案例,探讨了皮带机均匀分料技术改造方案。此项技术实现了均匀分料,为设备安全运行提供了可靠保障,节约了维修成本,提高了生产效率。

猴魁茶叶多级分料技术与试验研究

针对目前猴魁茶叶无法进行机械自动分料的问题,课题组在现有产线工艺的基础上提出了一种通过横分和纵分交叉组合的分料技术方案。通过对分料装置工作平台结构设计和整体布局,提升整体工艺流畅度;对技术方案所涉及关键结构参数进行相应试验研究,以获得最佳的工艺参数。结果表明:该方案可以实现茶叶87.3%的成功分离率,达到预期结果。该设计方案提供了一种新的猴魁茶叶自动分料方法,提高了生产效率。

分料技术在玻璃熔化中的应用

分料技术是玻璃熔化的一种新理念,通过该技术的实施可以增强玻璃液的横向对流,稳定泡界线,明显提高玻璃液质量。文中对该技术的实施要点进行了阐述分析。

Application of Electrical Capacitance Tomography to the Concentration Measurement in a Cyclone Dipleg

Accurate solid concentration measurement plays a key role in the process industry. Measurements analyzed offline can be used to estimate process efficiencies, to identify problems in a flow, and to validate computational models. Online measurements can be used for active control. Electrical capacitance tomography （ECT） is a unique measuring technique with great potential in multiphase flow measurement. Experimental studies are carried out on a solid concentration measurement in a cyclone separator dipleg, using ECT. In this experiment eight electrodes are selected for the ECT sensor that is placed on the straight tube of the dipleg. The fluctuating characteristics according to the screw feeder and the effect of the airflow rate from the top of the cyclone are analyzed. The feasibility andreliability of the method are verified by the experimental results.

3D analytical solution for a rotating transversely isotropic annular plate of functionally graded materials

The analytical solution for an annular plate rotating at a constant angular velocity is derived by means of direct displacement method from the elasticity equations for axisymmetric problems of functionally graded transversely isotropic media. The displacement components are assumed as a linear combination of certain explicit functions of the radial coordinate, with seven undetermined coefficients being functions of the axial coordinate z. Seven equations governing these z-dependent functions are derived and solved by a progressive integrating scheme. The present solution can be degenerated into the solution of a rotating isotropic functionally graded annular plate. The solution also can be degenerated into that for transversely isotropic or isotropic homogeneous materials. Finally, a special case is considered and the effect of the material gradient index on the elastic field is illustrated numerically.

Numerical Approach to the Mechanism of Cellulose Pyrolysis

A detailed mechanism analysis of cellulose pyrolysis was carried out according to the previous experimental results. On the basis of the Brodio-Shafizadeh model, a modified two-stage model was proposed to simulate the formation and decomposition of active cellulose (AC) and several main organic compounds, such as levoglucosan (LG), hydroxyl-acetaldehyde (HAA), acetol and furfural etc. During pryolysis, the temperature rise of cellulose can be divided into three stages. In the second stage, cellulose undergoes a main decomposition process in which the reaction temperature remains rather low because of the endothermic cracking of glucosidic bond of AC during the formation of LG. The components density of bio-oil, including LG and other competitive compounds, increased rapidly with the increase of temperature during the first stage. However, in the main decomposition process, LG density in bio-oil had an obvious decrease, while the competitive products appeared to increase gradually, which means the ring-opening and reforming reaction of pyranoid ring are superior to LG formation in high temperature.The secondary reaction of volatile components occurs largely in gaseous phase rather than in the solid phase. Short residence time of volatile materials in high temperature region will be advantageous to a high production of LG,which may otherwise decompose quickly under high temperature. An optimum yield of LG could be obtained when radiant source temperature is in the range of 730---920K and gas residence time is less than 1 s. In addition, the reaction temperature has a stronger effect than gas residence time on the formation of HAA, acetol, formaldehyde and furfural etc.

Performance of recycling abrasives in rock cutting by abrasive water jet

Rock cutting performance of recycling abrasives was investigated in terms of cutting depth, kerf width, kerf taper angle and surface roughness. Gravity separation technique was employed to separate the abrasives and the rock particles. The recycling abrasive particles were then dried and sieved for determination of their disintegration behaviors. Before each cutting with recycling abrasives, the abrasive particles less than 106 ?m were screened out. It is revealed that a considerable amount of used abrasives can be effectively reused in the rock cutting. The reusabilities of abrasives are determined as 81.77%, 57.50%, 34.37% and 17.72% after the first, second, third and fourth cuttings, respectively. Additionally, it is determined that recycling must be restricted three times due to the excessive disintegration of abrasives with further recycling. Moreover, it is concluded that cutting depth, kerf width and surface roughness decreases with recycling. No clear trend is found between the kerf taper angle and recycling. Particle size distribution is determined as an important parameter for improving the cutting performance of recycling abrasives.

Study on Separating Naphthenic Acids from Diesel Fuel by Microwave Irradiation

The microwave technology was introduced to separate naphthenic acids from diesel fuel. Thedecrease of zeta-potential of electric double layer on the W/O interface and the reduction of diesel fuelviscosity were responsible for the accelerated separation of naphthenic acids under microwave irradiation.The influences of dosage of alkali compound solvent (Mp/MT), irradiation pressure, irradiation time,irradiation power, the settling time and oil phase-to-solvent phase volume ratio (O/S) had been investigated.The optimum process conditions for the refining process were determined. The removal of naphthenicacids reached 98.4% when the optimum conditions were proposed as follows: Mp/MT=1.5, 0.05MPa, 6 min,375W, 25min and O/S=10, respectively. The diesel recovery could reach 99.3% and the quality of thetreated diesel oil was good enough to meet the specification of GB252-2000.

Design and Performance Analysis of Micro Proton Exchange Membrane Fuel Cells

This study describes a novel micro proton exchange membrane fuel cell(PEMFC)(active area,2.5 cm2).The flow field plate is manufactured by applying micro-electromechanical systems(MEMS) technology to silicon substrates to etch flow channels without a gold-coating.Therefore,this investigation used MEMS technology for fabrication of a flow field plate and presents a novel fabrication procedure.Various operating parameters,such as fuel temperature and fuel stoichiometric flow rate,are tested to optimize micro PEMFC performance.A single micro PEMFC using MEMS technology reveals the ideal performance of the proposed fuel cell.The optimal power density approaches 232.75 mW·cm-1 when the fuel cell is operated at ambient condition with humidified,heated fuel.

Performance of fixed geosynthetic technique of GRPS embankment

Geosynthetic-reinforced and pile-supported （GRPS） embankment has been increasingly constructed in a large number of regions and for a wide range of projects in the past decades. However, many disadvantages are exposed through a lot of applications on conventional technique of GRPS embankment （called CT embankment）, i.e., intolerable settlement and lateral displacement, low geosynthetic efficiency, etc. In view of these disadvantages, the fixed geosynthetic technique of GRPS embankment （called FGT embankment） is developed in this work. In this system, the geosynthetic is fixed on the pile head by the steel bar fulcrum and concrete fixed top. The principles and construction techniques involved in the FGT embankment are described firstly. Then, the numerical analysis method and two-stage analysis method are used to study the performance of FGT embankment, respectively. It is shown that the FGT embankment can provide a better improvement technique to construct a high embankment over soft ground.

Monte Carlo Simulation for the Adsorption of Symmetric Triblock Copolymers

The adsorption behavior of symmetric triblock copolymers, Am/2BnAm/2, from a nonselective solvent at solid-liquid interface has been studied by Monte Carlo simulations on a simple lattice model. Either segment A or segment B is attractive, while the other is non-attractive to the surface. Influences of the adsorption energy, bulk concentration, chain composition and chain length on the microstructure of adsorbed layers are presented. The results show that the total surface coverage and the adsorption amount increases monotonically as the bulk concentration increases. The larger the adsorption energy and the higher the fraction of adsorbing segments, the higher the total surface coverage is exhibited. The product of surface coverage and the proportion of non-attractive segments are nearly independent of the chain length, and the logarithm of the adsorption amount is a linear function of the reciprocal of the reduced temperature. When the adsorption energy is larger, the adsorption amount exhibits a maximum as the fraction of adsorbing segment increases. The adsorption isotherms of copolymers with different length of non-attractive segments can be mapped onto a single curve under given adsorption energy. The adsorption layer thickness decreases as the adsorption energy and the fraction of adsorbing segments increases, but it increases as the length of non-attractive segments increases. The tails mainly govern the adsorption layer thickness.

Optimal design considering structural efficiency of compressed natural gas fuel storage vessels for automobiles

The shape and thickness of the dome were investigated with the aim of optimizing the type II CNG storage vessels by using a finite element analysis technique. The thickness of the liners and reinforcing materials was optimized based on the requirement of the cylinder and dome parts. In addition, the shape of the dome, which is most suitable for type lI CNG storage vessels, was proposed by a process of review and analysis of various existing shapes, and the minimum thickness was established in this sequence： metal liners, composite materials and dome parts. Therefore, the new proposed shape products give a mass reduction of 4.8 kg（5.1%）

Development of a Sourcebook Using Neuro-Linguistic Programming Technique in Teaching English as a Second Language

This paper is an analysis of a sourcebook using Neuro-Linguistic Programming technique. The main objective is to determine the effectiveness of the sourcebook in teaching English as a second language. Specifically, it aimed to know the visual materials, aural presentations, and semi-abstract thoughts that would encourage the learners to actively participate in classroom discussions; the methods to be adapted; and the steps involved in the preparation of the sourcebook. It was found that most student-respondents strongly react to pictures, to feelings and sensations, and to ideas. The sourcebook must be prepared in the form of a content-based instructional material. It must include drills that would give ample approaches to develop among the learners good sense of collaborative learning, integrative global language proficiency, and contextual communicative competence in meaningful situations. Moreover, the sourcebook must use both print and non-print teaching aids as supporting materials.

BLIND SIGNAL SEPARATION OF LINEAR MIXTURE USING TRILINEAR DECOMPOSITION

This paper introduces a new source separation technique exploiting the time coherence of the source signals. The proposed approach relies only on stationary second order statistics. Blind Signal Separation (BSS) method using trilinear decomposition is proposed in this paper. Simulation results reveal that our proposed algorithm has the better blind signal separation performance than joint diagonalization method. Our proposed algorithm does not require whitening processing. Moreover, our proposed algorithm works well in the underdetermined condition, where the number of sources exceeds than the number of sensors.

Mechanical analysis of fixed geosynthetic technique of GRPS embankment

To overcome the deficiencies of conventional geosynthetic-reinforced and pile-supported (GRPS) embankment, a new improvement technique, fixed geosynthetic technique of GRPS embankment (FGT embankment), was developed and introduced. Based on the discussion about the load transfer mechanism of FGT embankment, a simplified check method of the requirement of geosynthetic tensile strength and a mechanical model of the FGT embankment were proposed. Two conditions, the pile cap and pile beam conditions are considered in the mechanical model. The finite difference method is used to solve the mechanical model owing to the complexity of the differential equations and the soil strata. Then, the numerical procedure is programmed. Finally, a field test is conducted to verify the mechanical model and the calculated results are in good agreement with field measured data.

Micromechanical analysis of damage evolution in splitting test of asphalt mixtures

A methodology was presented relating the microstructure of asphalt mixtures to their damage behavior. Digital image techniques were used to capture the asphalt mixture microstructure, and the finite element method was used to simulate the damage evolution of asphalt mixture through splitting test. Aggregates were modeled to be linearly elastic, and the mastics were modeled to be plastically damaged. The splitting test simulation results show that the material heterogeneity, the properties of aggregates and air voids have significant effects on the damage evolution approach. The damage behavior of asphalt mixture considering material heterogeneity is quite different from that of the conventional hypothesis of homogeneous material. The results indicate that the proposed method can be extended to the numerical analysis for the other micromechanical behaviors of asphalt concrete.

Design of reactive distillation processes for the production of butyl acrylate:Impact of bio-based raw materials

The chemical industry is nowadays predominantly using fossil raw materials,but the alternative use of bio-based resources is investigated to account for the foreseeable scarcity of fossil feedstocks.A main challenge of using biobased feedstocks is the complexity of the impurity profile.For an economic production of bio-based chemicals,the use of intensified processes is inevitable and approaches are needed for the various process intensification techniques to identify their applicability to be used for the production of bio-based components.In the presented study,an approach is shown for the reactive distillation(RD) technology to identify the most critical bio-based impurities and their impact on the reactive distillation process.The investigated case-study is the production of n-butyl acrylate from acrylic acid and n-butanol.Among all initially identified impurities,the key impurities,having the biggest impact on the product purity in the reactive distillation process,are found.These impurities are then studied in more detail and an operating window depending on the impurity concentration is identified for the reactive distillation column.Furthermore,an integrated design of upstream and downstream processes is facilitated,as the presented results can be used in the development of the fermentation processes for the production of the bio-based reactants by decreasing the concentration of the critical impurities.

Sensory Evaluation of Winter Cereal Silage

Silage is aimed at conservation of green fodder, with minimal losses and that this kind of food, does not occur formation of toxic compounds for animals. Practical aspects become important when control ＂in loco＂, reflects management practiced in the property. There are different sensory evaluation techniques. The objective of this work was to study the applicability of the German system, now used in sensory evaluation of winter cereals （wheat silage and haylage oats）. For quantitative analysis of silage （pH） that was used potentiometer. In determining the qualitative analysis was used German method adapted. Relating them to sensory characteristics such as smell, texture and color of the fodder saved by assigning a score to each sensory： a ＂key＂ predetermined quality identification. For multiple comparisons for film types tested in oat silages BRS Centauro, the results show that the qualitative sensory attributes evaluated by rating corresponded to the quantitative attributes （pH） evaluated, with no difference. For multiple comparisons in the silages, for all test loads in both wheat genotypes results showed no difference between the qualitative evaluation （sensory） and quantitative.