基于评标模式的公路工程造价研究

招标投标是我国工程项目进行施工承包重要的的方式。而评标的是公路工程的建设项目的招标投的标的关键环节。为了保证评标环节的公平、公正、科学、合理,保护招投标双的方的利益的,提高工程的建设的质量,研究科学、合理、有效的评标理论具有十分重的要的意义。     

对低压成套开关设备绝缘配合问题的探讨

电气工业的都配备有低压的成套的开关设备,我国的百分之八十左右的电能供给都是通过低压的成套的开关设备予以供出,低压的成套的开关设备的发展与工业材料制作,工艺产品和加工设备,低压的电器,人们的生活水平和基础的设施建设息息相关,所以它从一个侧面凸显了一个国家的综合国力,而其中的绝缘配合是一个关联到电气产品的安全性的至关重要的问题,应该要有非常的重视     

阐析高速公路路基的路面施工

我国的交通运输行业的发展借助的是我国的经济的高速的发展。我国交通运输业的发展也直接带动了我国的高速公路的发展。在我国的高速公路的建设过程中,关于路基路面的施工还是存在着很多的问题的。本文针对高速公路路基路面施工的问题,来进行相关的讨论和分析,讨论高速公路路基施工中的施工工艺的应用,为高速公路的建设贡献自己的力量。     

220kV变电站主接线运行经济性选择的探讨

变电站的主接线的设计是依据变电站的最高电压以及变电站的性质决定的。通过地区的电网的运行的实际情况出发,对220kv的变电站的主接线的运行进行了详细分析,并对变电站的主接线的设置进行了比较与分析。     

如何进行施工项目的管理和成本的控制工作

随着我国经济的不断发展,我国的基础设施的施工工程越来越多,在施工的过程中,施工项目的管理工作越来越重要。作为现代的企业来讲,施工的项目管理是非常的重要的,这主要是因为施工的企业只有做好施工项目的管理工作才能不断的完善现在的企业管理制度,使企业的管理工作更加的完善。企业只有做好施工项目的管理工作才可以提高企业的经济效益,进行项目施工的时候一定要进行必要的成本控制,这样才能够使企业的社会信誉得到提高,并且可以使企业的发展空间得到更大的提升。     

石化行业的污水处理探析

伴随着世界范围内的资源再利用的步伐,我国的石化行业的从业单位不断的发展壮大,与此同时人们的环保概念不断的在进行加强。石化行业的污水的处理方式已经越来越受到社会的关注。如何处理石化行业的污水已经是一种议题。随着我国的工业化程度的深入,我国石化行业的工业废水已经变化的多种多样,很多的化学污染物掺杂其中,这样就会对我们的化工行业的污水处理带来很多的困难。针对这种现状,我们要做的就是要不断的提升化工行业污水处理的质量和效率。本文就是针对这种问题来进行详细的论述。     

浅析当前公共财政政策存在的问题及对策

随着我国改革开放的不断的深入进行以及社会主义市场经济的建立和不断的完善,极大的改变了我国公共财政所面对的环境。当前我国的财政体制改革起的了很大的成功,极大的促进了我国经济的发展,但是在财政体制改革的过程当中也暴露出我国公共财政存在的一些问题。文章对当前我国公共财政存在的问题进行了深入的分析,并有针对性的提出了改进的建议,促进我国公共财政的发展。     

建筑施工中室外照明的接地故障保护和短路保护方法之研究

随着我们国家的经济的迅猛发展,人们的生活水平也是越来越高。人们对周围的环境的要求也是越来越严格。照明系统作为城市道路的一个明显的环节。由于室外的照明的场所的不同,所以室外照明供电系统的供电的方式也是不一样的。本文是通过对室外照明线路的选择以及供电系统的选择进行分析,为以后的室外照明的相关工程提供有利的依据。     

热电厂电气的安全使用

热电厂电气的安全使用包含的有几个方面的内容。主要分为热电厂电气主设备的安全选择、热电厂电气运行的安全管理的措施、在工作中防治电气失误操作的措施和对策以及在热电厂安全生产中的个性化和人性化的管理等等。热电厂电气的安全使用对电厂的生产以及人们的正常的生产和生活都有重要的意义,因此,本文通过对热电厂电气的安全使用的几个方面的论述来进一步说明在热电厂的工作流程中电气的安全使用所占有的重要地位。特别是在经济迅速发展的中国,在电力建设的规模不断扩大的中国,作为热电厂的一名工作人员,更是要尽自己的力量来使电厂的各方面得到快速协调的发展。通过对热电厂电气的安全使用的论述,使得热电厂向着速度更快、电容量更大、参数更高以及电网更大的方向发展。     

浅谈信息时代网络环境下的教学模式

网络环境下的教学模式是信息时代的教育所面临的必然选择,从网络环境下的教学模式的特点,网络环境下的教学模式的要求,网络环境下的教学模式的发展的意义等几个方面论述网络环境下的教学模式的重要性和迫切性。     

Shrinkage compensation approach proposed for ABS material in FDM process

Dimensional accuracy of parts manufactured by Fused Deposition Modelling (FDM) greatly suffers from the shrinkage problems of the available polymer materials. This paper proposes a constructive idea for resolving the shrinkage issues and explains how shrinkage could be managed by interior geometry of the artifacts fabricated on desktop 3D printers. The main principle for preventing the deterioration on dimensional accuracy of the holes/slots is to utilize the auxiliary lines located from the hole’s perimeter to the outer boundaries of the artifact. Thus, the shrinkage of these auxiliary line segments simply helps to pull the original hole backward, acting against the predicted contraction. In this paper, the proposed approach will be examined using a finite element analysis tool to predict the shrinkage behavior of the fabricated samples along with necessary measurements taken on the Coordinate Measuring Machine. Additionally, an analytical framework for modeling the shrinkage behavior of ABS is to be elaborated. The coherence of the simulations and the measurements are to be analyzed regarding the effect of the geometry and material color on the shrinkage behavior. The discussion involves the improvement on the dimensional accuracy of 3D printed features.     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Ice formation process by cooling water–oil emulsion with stirring in a vessel

An emulsion, which was a mixture of silanol-aqueous solution and silicone oil, was investigated as a heat storage material for a dynamic type ice storage system. The emulsion was poured into a vessel, which was immersed into a constant temperature bath at a low temperature, and frozen with stirring. Using stainless steel vessels coated with PFA resin and PTFE vessels with different thickness, the experiments were carried out under various conditions of temperature. Measuring the temperature history in the vessel, overall heat transfer coefficients before the start of freezing and during the ice formation were obtained. The effects of the material of the cooling surface and the thermal resistance of the wall on the ice formation process were clarified. If the heat flux of the wall was less than a critical value, slurry ice was formed without adhesion to the cooling surface. The results obtained under the same condition of the thermal resistance proved that it was effective against ice adhesion to coat PFA resin inside the vessel. It was found by the experiments in which the PTFE vessels were used that the critical value of the heat flux was nearly constant regardless of the thermal resistance.     

Effect of deflecting ring on noise generated by outdoor set of a split-unit air conditioner

In order to analyze the influence of the deflecting ring on the noise generated by the outdoor set of a split-unit air conditioner, the flow field in the outdoor set is simulated with the CFD software STAR-CD, the relative turbulent intensities are computed and the influence of the width and contoured duct of the deflecting ring on the noise generated by the outdoor set is analyzed. The results of computation and experiment show that there is an optimal width of the deflecting ring, corresponding to the minimum noise generated by the outdoor set. In addition, the influence of the contoured duct of the deflecting ring on the noise generated by the outdoor set is analyzed and a double contoured duct is designed. The results of computation and experiment verify that the deflecting ring with double contoured duct can improve the aerodynamic performance and reduce the noise generated by the outdoor set.     

Tribologische Kennwerte für Reibwerkstoffe

Tribology parameters for friction materials The tribology parameters of the friction materials are currently the coefficient of friction and the wear coefficient. They are determined depending on the material, the surface pressure and the frictional speed. These two parameters are not sufficient for an evaluation of the friction materials on the basis of a wear theory. Their validity is therefore limited. It is proposed to evaluate the friction materials on the basis of the energetic wear theory. The parameters are then the wear energy density, the shear stress of friction and the linear wear intensity. These values can be shown in a diagram and allow for the direct comparison of widely varying friction materials. The reference coefficient of friction is being introduced as a new wear parameter. The determination of the proposed parameters is made on a flywheel test rig, combined with the laser‐optical online measurement of the wear particles. It was possible to demonstrate that the parameters correctly describe the practice‐relevant requirements using two proven friction materials.     

Parametric optimization of a new combined refrigeration cycle – active thermal potentiostatting system

The active thermal potentiostatting system proposed by Martinovskii and Tsirlin is directly generalized to a more practical case, in which one intermediate chamber, besides a thermal potentiostatting chamber, and two irreversible refrigeration cycles are included and the influence of the thermal resistance between the working fluid and the reservoirs, the heat leakages from the environment to the intermediate chamber and from the intermediate chamber to the potentiostatting chamber are taken into account. Expressions for the main parameters of the system are derived. By using the optimal control theory, the minimum total power input of the system with non-zero cooling rates is calculated and the temperatures of the working fluid in the isothermal processes of the refrigeration cycles are optimized. The optimal allocation of the heat-transfer areas of the heat-exchangers in the refrigeration cycles is discussed in detail. The results obtained here are more general and useful than the relevant results in literature and can provide some valuable guidance for the optimal design and operation of real active thermal potentiostatting systems.     

Verbesserung des Eigenspannungszustands beim Kaltfließpressen durch den aktiven Einsatz eines gesteuerten Gegenstempels

By using an active counter punch during cold extrusion, the residual stress of the component can significantly be improved, which can increase its fatigue strength. In general, the workpieces produced through full‐forward extrusion are characterized by a strongly unfavourable stress state: The resulting high axial tensile residual stresses on the surface as well as the steep stress gradient accelerate the formation and the growth of cracks during cyclic loading. A system developed by the authors, consisting of a counter punch actively employed during the forming process allows improving the residual stress state of the final product. This result is obtained through a homogenization of the deformations in the samples during the cold extrusion. Therefore, a finite element simulation of the process was developed in Simufact Forming®. The simulation was experimentally validated by using the two austenitic steels 1.4307 and 1.4404. Another focus is the development of suitable measuring strategies for the X‐ray residual stress analysis with the sin²Ψ‐method to ensure the quality of the measurement results despite coarse‐grained and anisotropic microstructures. The results of the simulations and the experiments show that his technique has a considerable potential to increase the product quality without modifying the process time.     

An experimental study on minimizing frost deposition on a cold surface under natural convection conditions by use of a novel anti-frosting paint. Part II. Long-term performance, frost layer observation and mechanism analysis

In this part of study, the comparative observations of the structure and the surface temperature of the frost layer of both the coated and uncoated surfaces ware carried out and a preliminary analysis was presented. A series of the repeated cycling tests were completed that lasted for more than 2 months, and the influences of the coating thickness were also investigated. The results show that the frost layer deposited on the coating surface has a very fragile structure and can be removed easily by external force. The coating thickness has an important effect on the anti-frosting performance of the paint. The results also show that the coating of the paint on the copper surface is durable and presents a very good repeated cycling performance.     

The Influence of Nitrogen and Boron Implant into Silicon Substrate on the Phase and Internal Stress of c-BN Films

Cubic boron nitride(c-BN) film was deposited on a Si (100) substrate by the RF-magnetron sputtering.The mainly problems for fabrication of c-BN films are the low purity and high intrinsic compressive stress. In order to solve the two problems, the c-BN film with the buffer interlayer was deposited on the substrate which had been implanted with nitrogen and/or boron ions. The results show: the implantation of nitrogen ions can obviously increase c-BN content and reduce the internal stress slightly; while the implantation of boron shows no obvious improvement to the content of c-BN, which can reduce the internal stress in the film obviously. In addition, it is suggested that the implantation of nitrogen and boron shows the best result, which not only can increase the content of c-BN, but also reduce the internal stress in the c-BN film obviously.