输电线路铁塔塔腿辅助材布置方案分析

随着电压等级的升高和铁塔尺寸的加大,塔腿高度也越来越大,由此导致腿部辅助材节间数增加。以某工程设计实例为依托,通过对比不同的塔腿辅助材布置方案,从节约钢材和给主材提供有效支撑及优化布置的角度进行研究并确定推荐方案,进而得到选择合理的塔腿辅助材布置方案的原则,并提出优化建议。

输电线路铁塔辅助材研究

在理论分析的基础上,通过真型试验验证,对输电线路铁塔辅助材受力进行了分析研究,提出了一些设计建议。

电磁辅助电弧熔丝增材制造GH4169合金的组织和疲劳性能

采用电磁辅助TIG电弧熔丝增材制造在1Cr18Ni9Ti不锈钢基板上制备了GH4169合金,分析了GH4169合金的凝固组织,研究了励磁电流对GH4169合金室温疲劳性能的影响。结果表明,电磁辅助电弧熔丝增材制造GH4169合金组织致密,无明显气孔、裂纹等缺陷。成形试样的宏观组织由沿沉积方向自下而上外延生长的粗大柱状晶组成,在施加外部磁场后,柱状晶尺寸减小,当励磁电流为1 A时,枝晶间脆性Laves相含量最少,元素的显微偏析现象减弱;随励磁电流的增大,成形试样的室温疲劳性能呈现先增大后减小的趋势,当励磁电流为1 A时,其疲劳寿命达到1.1×10^(6),成形试样的室温疲劳性能最佳。

输电铁塔辅助材承载能力分析及设计研究

对于输电铁塔辅助支撑材的设计,各规范要求差异较大,对中国、美国、欧洲以及印度规范的相关条文进行梳理,并将其结果与铁塔真型试验实测数据以及有限元数值模拟分析数据进行对比分析,提出中国输电铁塔辅助材设计的建议公式,经验证满足工程设计要求,可作为相关规范修编的参考。

激光辅助增材制造CoCrNi中熵合金的纵向力学性能研究

针对钴铬镍(CoCrNi)增材制造过程中,因热传导具有方向性,且受层间结合强度和材料显微结构影响,导致CoCrNi的纵向(平行于材料沉积方向)力学性能(屈服强度、抗拉强度、延伸率)较差的问题,采用激光辅助增材制造方法制备CoCrNi中熵合金。实验结果发现:随着打印工件沉积高度增加,散热性变差,出现较大的外延晶,且产生热裂纹;制备的CoCrNi纵向力学性能明显低于文献[9]的横向力学性能,但保持了相对较好的强度和韧性。

复合式增材制造技术研究现状及发展

形性问题制约金属增材制造技术的发展与应用,复合式增材制造在解决制件形性问题方面效果显著。高度概括了复合式增材制造技术分类方式与主体类别;简要总结了增减材复合制造在制件成形精度和表面质量控制方面的研究进展和技术发展状况;重点评述了增等材复合制造技术类别、成形原理、制造特征和关键问题,以及在制件显微组织、应力状态、宏观性能调控方面的研究现状和主体结论;系统介绍了超声、电磁、激光三类特种辅助能场对增材熔池流动、结晶、固态相变的作用机制,以及特种能场作用下,增材层显微组织状态、力学性能、成形精度的演化规律;展望了复合式增材制造技术未来的发展趋势。

Influences of electric-hydraulic chattering on backward extrusion process of 6061 aluminum alloy

The possibility of the electric-hydraulic chattering technology and its application in the cold extrusion were presented.The conventional and electric-hydraulic chattering assisted backward extrusion processes were performed on 6061 aluminum alloy billets at room temperature.The experimental results showed that 5.65% reduction in the extrusion load was attained if the die and ejector were vibrated at a frequency of 100 Hz and amplitude of 0.013 mm in the longitudinal direction.The friction coefficient at the billet and tool system interface determined from the finite element analysis（FEA） decreased from 0.2 without chattering to 0.1 with application of electric-hydraulic chattering.The higher values of instantaneous velocity and direction change of material flow were achieved during the chattering assisted backward extrusion process.The strain distribution of the chattering assisted backward extrusion billet revealed lower maximum strain and smoother strain distribution in comparison with that produced by the conventional extrusion method.

Effects of Cigarette Auxiliary Material Parameters on Release Amounts of Tar, CO and Free Radicals in Cigarette Mainstream Smoke

[Objective] This study aimed to investigate the effects of cigarette auxiliary material parameters on release amounts of tar, CO and free radicals in cigarette mainstream smoke. [Method] The effects of cigarette paper air-permeability, cigarette paper gram weight, filter rod pressure drop and filter tip ventilating strength parameters on the release amounts of tar, CO and free radicals in cigarette mainstream smoke were investigated by single factor experiment and orthogonal experiment. [Result] The cigarette paper air-permeability, filter rod pressure drop and filter tip ventilating strength showed significantly negative correlation with the release amounts of tar, CO and free radicals in cigarette mainstream smoke, to be specific, the cigarette paper air-permeability showed the greatest effect on the release amounts of tar and CO, filter tip ventilating strength showed the greatest effect on the release amounts of gaseous-phase free radicals and particulate-phase free radicals, while cigarette paper gram weight showed relatively slight effect on the release amounts of tar, CO and free radicals. Within the orthogonal experimental range, the optimal program is identified as cigarette paper airpermeability of 70 CU, filter rod pressure drop of 4500 Pa/unit, and filter tip ventilating strength of 60 CU. Compared to the results without optimization, the release amounts of tar, CO and free radicals after optimization were all reduced. [Conclusion] This study laid the foundation for the research of cigarette tar reduction and harm reduction.

Effect of Electrolyte Impurities within Starch on the Adhesion of Quaternary Ammonium Starch to Fibers

Influences of some electrolyte impurities within starch and starch cationization on the adhesion of quaternary ammonium cornstarch to cotton and polyester fibers were investigated. The electrolytes considered included NaCI, Na2SO4, NaH2PO4 and Na2HPO4. The adhesion to fibers was evaluated in terms of maximum strength and work-to-break of the roving sized with the starch pastes containing electrolytes. It was found that the cationization showed a positive effect on the adhesion to both fibers whereas the electrolytes gave an adverse effect and reduced the adhesion. The adverse effect depends on the type and amount of electrolytes. The influence of electrolytes on the adhesion can be ranked in a series of NaH2PO4〉 Na2 HPO4〉 Na2SO4 〉 NaCl. The adhesion enhances as the modification extent increases and the electrolyte content decreases. Furthermore, the adverse effect can be compensated by the positive effect of the starch modification even at a low modification extent. If the electrolytes are fully eliminated, the cationic starch can increase the adhesion strength by more than 10% for both fibers.

Mechanical properties of pervious cement concrete

Compressive and flexural strength,fracture energy,as well as fatigue property of pervious cement concrete with either supplementary cementitious materials (SCMs) or polymer intensified,were analyzed.Test results show that the strength development of SCM-modified pervious concrete (SPC) differs from that of polymer-intensified pervious concrete (PPC),and porosity has little effect on their strength growth.PPC has higher flexural strength and remarkably higher flexural-to-compressive strength ratio than SPC at the same porosity level.Results from fracture test of pervious concrete mixes with porosity around 19.5% show that the fracture energy increases with increasing the dosage of polymer,reflecting the ductile damage features rather than brittleness.PPC displays far longer fatigue life than SPC for any given failure probability and at any stress level.It is proved that two-parameter Weibull probability function describes the flexural fatigue of pervious concrete.

URI Online Judge： A New Interactive Learning Approach

The URI online judge is a new online tool created with the main purpose of making programming practice more dynamic, interesting and stimulating for those who have just entered into the art of programming. The URI online judge allows problem corrections in real time, interactivity between users, besides it allows flexibility in the choice of the programming language and it makes some supporting materials available. During the short time in which the tool has being used we have observed that it is a very good tool for self-study. As users of programming portals, the authors noticed some details that would be important to be implemented in a new tool, such as the separation of problems by categories. Another fundamental detail is the fact that this tool is available in two languages （Portuguese and English）. This might facilitate the learning process for beginners, both locally and globally.

Information on a New Field of Knowledge： Metallurgical Econology

A new branch of science called econology is being defined and shortly characterized as studying the economics-ecology-energy associations （3E or E3 associations）. In the future, this must be transformed into tehnology （T）-economy-energy-ecology, so that the symbol of the econology shall be TE3. Being a new field, it becomes necessary to define and characterize the specific methodological tools. That＇s why the paper examines the following indices： （1） specific consumption of primary carbon; （2） specific consumption of primary negentropy; （3） reintegration rate of secondary materials and energy. Also, the following issues are presented： （1） the indirect pollution mechanism in metallurgy; （2） analysis of pollution issues by principle ＂think globally, act locally＂.

Na2FePO4F/C composite synthesized via a simple solid state route for lithium-ion batteries

Using low-cost FePO4·2H2O as iron source,Na2FePO4F/C composite is prepared by alcohol-assisted ball milling and solid-state reaction method.The XRD pattern of Na2FePO4F/C composite demonstrates sharp peaks,indicating high crystalline and phase purity.The SEM and TEM images reveal that diameter of the spherical-like Na2FePO4F/C particles ranges from 50 to 300 nm,and HRTEM image shows that the surface of Na2FePO4F/C composite is uniformly coated by carbon layer with a average thickness of about 3.6 nm.The carbon coating constrains the growth of the particles and effectively reduces the agglomeration of nanoparticles.Using lithium metal as anode,the composite delivers a discharge capacities of 102.8,96.4 and 90.3 mA·h/g at rates of 0.5C,1C and 2C,respectively.After 100 cycles at 0.5C,a discharge capacity of 98.9 mA·h/g is maintained with capacity retention of 96.2%.The Li+diffusion coefficient(D)of Na2FePO4F/C composite is calculated as 1.71×10^–9 cm^2/s.This study reveals that the simple solid state reaction could be a practical and effective synthetic route for the industrial production of Na2FePO4F/C material.

Study on Fresh Yam Fermented Milk Technology

[ Objective] The aim was to study the fermentation of yam and lactic acid bacteria. [Method] Taking fresh yam as main materials, optimized wheat, skimmed milk and white sugar as auxiliary materials, the lactic acid bacteria developed into healthy drinks with unique flavor. The ratio of raw materials, the best conditions for hydrolysis of malt, lactic acid fermentation process conditions, such as product formulations were studied. [ Result ]The best conditions for the yam matt enzyme dosage was 21.0%, malt dosage 1.4%, reaction temperature 68℃, hydrolysis time 60 min; optimal fermentation process to increase milk production 2.4% , fermentation temperature 38 ℃, fermentation time 7. 0h, inoculums size 5.0%. [ Conclusion] The fresh yam tastes fresh, sour and sweet. The natural white ram is of high quality.

Solenoid Actuator Design for Improvement of Response Speed

The main design factors which effect on operating speed of solenoid actuator for valve operation are mass of plunger, electromagnetic motive force, inductance and return spring, and these factors are not independent but related with each other in view point of design and electromagnetic theory. It is impossible to increase the operating speed by only change the value of any one design factor. The change of any one value results in change of any value related it in various design factors. Permanent magnets are as assistant materials which make higher flux density in air gap. Electromagnetic motive force in controlled only by current. This paper presents a speed increasing design method of solenoid actuator using a solenoid, by some governing equations which are composed of electromagnetic theory and empirical knowledge, and proved the propriety by experiments.

Sustainable Design of Turbofan Engine： A Computer-Aided Design and Finite Element Analysis

A compressive design and analysis of a turbofan engine is presented in this paper. The components of jet engine have been analyzed based on mechanical design concept. An attempt has been to select materials based on sustainability and green design considerations. The energy content （e） of the materials has been one of the parameters for material selection. The choice of material has a substantial impact on cost, manuthcturing process, and the life cycle efficiency. All components nose cone, fan blade, inlet shaft, including compressor has been solid modeled using Siemens NX 11.0 CAD software. The finite element analysis of every component was performed and found safe. A tolerance analysis was performed before assembly of the turbofan engine. A numerical analysis was completed on blade and inlet geometries to determine a more efficient turbofan engine. Thermal analysis was executed oi1 the cone and suitable corrections were made. Finally, the cost and the total energy were estimated to show how much energy is needed to manufacture a turbofan jet engine.

Experimental Study on the Use of Trass as a Supplementary Cementitious Material in Pervious Concrete

Abstract： The purpose of this paper is to evaluate the suitability of using trass as a supplementary cementing material in pervious concrete. OPC （Ordinary Portland Cement） was replaced in the concrete mix by 15%, 25% and 35% weight percentages and the results were compared with reference mixtures with 100% Portland cement. The variables in this study were trass content, aggregate size and water to cement ratio. Sixteen eases of concrete mixtures were tested to study physical and mechanical properties of hardened concrete, including porosity, permeability, compressive strength, splitting-tensile strength and flexural strength at various ages. Results indicated that mechanical properties of the pervious concrete marginally decreased with the increased content of trass when compared to the reference mixtures. However, at later ages the differences were insignificant.

Possibilities for Increasing Sunflower Resistance to Broomrape （ Orobanche cumana Wallr.）

Broomrape causes economic damage in sunflower production in many countries worldwide, but especially in Central and Eastern Europe, Spain, Turkey, Israel, Iran, Kazakhstan, and China. Sunflower selection for broomrape resistance uses different methods for testing breeding materials, looks for resistance sources in certain wild species of the genus Helianthus, and has so far produced significant results. Dominant genes for resistance to races A, B, C, D, E and F have been found and incorporated into cultivated sunflower genotypes. In the last two to three years, new broomrape populations have been discovered in several countries. None of the existing commercial hybrids resistant to races A, B, C, D, E and F have proven resistant to these new populations. Greenhouse testing conducted by the Fundulea Institute in Romania in 2009 has managed to identify two restorer lines that are resistant to all the new populations and can be used directly in developing hybrids. Sunflower breeders and geneticists have achieved significant results in the use of molecular markers for identifying new broomrape races. Marker-assisted selection should be used even more in the future search for Orobanche resistance. Broomrape can also be managed by the development of IMl-resistant hybrids or by using biological control.

Mechanical Properties and Fracture Behavior of Laminated Heterostructured Composites Under Different Current Densities

The mechanical properties and fracture morphologies of Cu/Nb multilayer composites under electric-assisted tension(EAT)were investigated.Results show that the generated Joule-heat leads to obvious stress softening with the increase in current density.However,the elongation decreases,which is closely related to the characteristic fracture behavior of Cu/Nb multilayer composites during EAT.The fracture pattern is gradually transformed from ductile fracture to melt fracture with the increase in current density.

Initial search for low grade clay in Pakistan for producing LC^(3) ecofriendly cement

Industrialization has though brought comfort to our daily lives,but it has placed a lot of pressure on the planet’s natural resources,subsequently,it has adversely affected the environment.As the need for cement in the construction sector has grown,it has climbed dramatically globally.Around the world,more than 10 billion cubic meters of concrete are produced each year;it is doubtful that this volume will decrease.A significant expected rise in CO_(2) emissions is caused by increased cement demand.According to the UN Environment Program,buildings are responsible for up to 41%of global anthropogenic carbon emissions.The primary source of greenhouse gases utilized in the manufacturing of cement is clinker.Due to the unsustainable supply of fly ash,calcined clay appears to be a better Supplemental Cementitious Material(SCMs).Kaolin clay is widely available in Pakistan.The purpose of this investigation is to describe the mineral and thermal characteristics of Pakistani clays by examining their geographic distribution.Clay samples were gathered from 39 different places throughout Pakistan during a field investigation program.X-ray diffraction,X-ray Fluorescence,Reactivity,and thermogravimetric analyses were used to analyze the clay samples’mineral content and thermal characteristics.This study demonstrates that Pakistan has a substantial amount of kaolin clay reserves close to existing groups of cement plants.Pakistani clays can be utilized as SCM in the production of limestone calcined clay cement(LC^(3))due to the country’s vast kaolin clay reserves.This study further supports the viability of producing LC^(3) in the nation by providing a thorough analysis of the cement business,known deposits of qualifying clay,and the country’s cement production process.