Influence of high-speed milling parameter on 3D surface topography and fatigue behavior of TB6 titanium alloy

High-speed milling of titanium alloys is widely used in aviation and aerospace industries for its high efficiency and good quality.In order to optimize the machining parameters in high-speed milling TB6 titanium alloy,experiments of high-speed milling and fatigue were conducted to investigate the effect of parameters on 3D surface topography and fatigue life.Based on the fatigue fracture,the effect mechanism of surface topography on the fatigue crack initiation was proposed.The experiment results show that when the milling speed ranged from 100 m/min to 140 m/min,and the feed per tooth ranged from 0.02 mm/z to 0.06 mm/z,the obtained surface roughness were within the limit（0.8 μm）.Fatigue life decreased sharply with the increase of surface equivalent stress concentration factor.The average error of fatigue life between the established model and the experimental results was 6.25%.The fatigue cracks nucleated at the intersection edge of machined surface.

Comparative analysis of perpetual pavement structures based on pavement performance and life cycle cost

Pavement performance and economic efficiency are researched on the perpetual test pavement of Yijiang-Suzhou Express Highway in Jiangsu province, China. Test sections were continuously monitored. The conditions and developing laws of deflection, rutting and cracking are compared among the perpetual pavement with the rich binder layer （RBL）, the perpetual pavement without the RBL, and the conventional semi-rigid asphalt pavement in the past eight years after opening for traffic. Economical evaluation is conducted via life cycle cost analysis （LCCA）. Based on the performance comparison and LCCA analysis, sections with the RBL have good crack resistance, but they are not very satisfactory in the aspect of permanent deformation; the conventional semi-rigid asphalt pavement is the least economic one due to requiring more frequent maintenance. Research results show that the perpetual pavement without RBL is a more appropriate structure for the test site.

Effects of surface finish and treatment on the fatigue behaviour of vibrating cylinder block using frequency response approach

This paper presents the effects of surface finish and treatment on the high cycle fatigue behaviour of vibrating cylinder block of a new two-stroke free piston engine at complex variable amplitude loading conditions using frequency response approach. Finite element modelling and frequency response analysis was conducted using finite element analysis software Package MSC.PATRAN/MSC.NASTRAN and fatigue life prediction was carded out using MSC.FATIGUE software. Based on the finite element results, different frequency response approach was applied to predict the cylinder block fatigue life. Results for different load histories and material combinations are also discussed. Results indicated great effects for all surface finish and treatment. It is concluded that polished and cast surface finish conditions give the highest and lowest cylinder block lives, respectively; and that Nitrided treatment leads to longest cylinder block life. The results were used to draw contour plots of fatigue life and damage in the worst or most damaging case.

Failure analysis study of railway draw-hook coupler

Failure analysis of railway draw-hook coupler was carried out.The nondestructive testing method was undertaken on some failed couplers in service to designate critical areas of a coupler.Draw-Hook coupler is used to connect with the same hook coupler or automatic coupler.The influence of each connection types on the coupler strength in this study was discussed.A numerical stress analysis using FEM was performed,and many approaches including critical plane approach were carried out on fatigue life prediction of coupler under different conditions.The results of the proposed fatigue criterion and fatigue life predictions,as well as static numerical analysis,are validated with experimental results.

Fatigue life prediction of workpiece with 3D rough surface topography based on surface reconstruction technology

The fatigue performance of a workpiece depends on its surface quality.In traditional fatigue life prediction,the effect of surface quality is commonly accounted for by using empirical correction factors,which is imprecise when safety is of great concern.For surface quality,the surface topography is an important parameter,which introduces stress concentration that reduces the fatigue life.It is not feasible to test the stress concentration of different surface topographies.On the one hand,it is time-consuming and high-cost,and on the other hand,it cannot reflect the general statistical characteristics.With the help of surface reconstruction technology and interpolation method,a more efficient and economic approach is proposed,where FE simulation of workpiece with the reconstructed surface topography is used as a foundation for fatigue life prediction.The relationship between surface roughness(Sa)and fatigue life of the workpiece is studied with the proposed approach.

The decision-making dimension of the systems approach to management

Theoretically, a system is anything that is made up of various parts. Theses parts are known as subsystems. At every point in time, these parts should work in harmony so that objectives could be achieved successfully. A system could be inanimate or animate item. Examples of inanimate systems include vehicles, households, computer and institution. Examples of animate systems are human being, animal and insect. Both inanimate and animate systems are made up of various subsystems. Such subsystems are required to co-operate, collaborate and work together so that set objectives could be achieved successfully. From practical managerial point of view, business organizations are equally systems that are made up of subsystems which may take the form of departments, sections and/or units. It is supposed to be collaborations among the managers and other members in these departments, sections and/or units so that organizational objectives could be achieved. All the managers in various departments, sections and/or units are required to work together as a team to make the system coherent and closely-knit to make disintegration impossible. Closely related to the systems approach to management is managerial decision-making. Decision-making is a very important function of every manager＇s job. The success and failure stories of many organizations are the result of the quality of decisions made. Many organizations have survived turbulent conditions. Others have also collapsed in spite of favourable conditions. These varying conditions are the result of the quality of decisions made by managers at positions of authority and responsibility. Therefore the systems approach to management enjoins top managers in particular to be very circumspect and cautious in certain decision-making activities. This is because, the quality of decision a manager makes can go a long way to determine the success or failure story of an organization as exemplified in the case study in this paper.

Investigation of the environmental impacts of steel deck pavement based on life cycle assessment

To investigate the environmental impacts of steel deck pavement through the whole life cycle,the steel deck pavement was divided into five stages:raw materials production,asphalt mixture mixing,pavement construction,operation management,and pavement removing stage.Based on the process-based life cycle assessment(PLCA)method,the calculation methods of energy consumption and gas emissions of two typical steel deck pavement systems(EA+EA pavement and GA+SMA pavement)were determined.The data lists of two pavements were analyzed,and the calculation model was built.Four characteristic indices including primary energy demand(PED),global warming potential(GWP),acidification potential(AP)and respiratory inorganics(RI)were used to quantify the environmental impacts of two pavements.The results show that the environmental impact of the GA+SMA pavement is more than 1.3 times that of the EA+EA pavement.Moreover,the critical stage of energy-saving and emission-reduction of EA+EA pavement and GA+SMA pavement are the raw material production stage and asphalt mixture mixing stage,respectively.

西周册命制度补论

西周任命官员,在册命之前,其实还有一个面命的程序。认识到这一点才能理顺命书与"王若曰"所引领文字之间的关系,准确理解册命的功能和意义。

Construction of life cycle assessment software system platform

There has not been life cycle assessment (LCA) software applicable to China's products. To faciliate the development of LCA software system in China, we built an object-oriented LCA software system plantform based on LCA international standards ISO 14040 to ISO 14043 and the commonness of diverse products. The system includes six modules: disassembly module, data collection module, arithmetic module, drawing module, database module and control module. It evaluates all economic and environmental impacts during the whole life cycle of a product. The integrated life cycle inventory database system allows dynamic expansion, which makes the effort required for data collection reduce with the increase of the system's application. With the improvement of human environmental-awareness, the demand of environment-friendly products is increasing, and ecological design of products has become a critical part in products development. Consummation of the LCA software system will provide a powerful tool for designing and developing Chinese ecological products.

Effect of Traffic Speed on Stresses and Strains in Asphalt Perpetual Pavement

Increasing traffic volumes and loads as well as public expectation for a long-lasting transportation infrastructure have necessitated designing perpetual pavements. The KDOT （Kansas Department of Transportation） conducted a field trial to investigate the suitability of perpetual pavement concept for Kansas highway pavements. The experiment involved construction of four thick pavement structures. To verify the approach of designing perpetual pavements on the basis of an endurance strain limit, the pavements were instrumented with gauges for measuring tensile strains at the bottom of asphalt base layers at various speeds. Pavements were also instrumented with pressure cells to measure stress on the top of subgrade. Pavement response measurements under known vehicle load were performed in August 2006. FWD （Falling-weight deflectometer） was also used to collect deflection data at 15 m intervals on the same date. FWD first-sensor （center） deflections were normalized and corrected to 20 ℃ temperature based on measured mid-depth pavement temperature. The result shows that strain and stress measurements show significant amount of variations. Measurements in the thickest section are the most consistent. The higher the traffic speed, the lower the strains and stresses. The difference between strains and stresses at 30 kmhar and 65 km/hr is higher than the difference between 65 km/hr and 95 kin/hr. This shows the effect of speed on stresses and strains decreases as the speed increases. Softer binder in the asphalt base layer results in lower strains, which confirms that softer binder results in higher fatigue life.

Speech Recognition Technology Applied to Intelligent Mobile Navigation System

The capability of human_computer interaction reflects the intelligent degree of mobile navigation system.The navigation data and functions of mobile navigation system are divided into system commands and non_system commands in this paper.And then a group of speech commands are abstracted.This paper applies speech recognition technology to intelligent mobile navigation system to process speech commands and does some deep research on the integration of speech recognition technology with mobile navigation system.The navigation operation can be performed by speech commands,which makes human_computer interaction easy during navigation.Speech command interface of navigation system is implemented by Dutty ++ Software,which is based on speech recognition system _Via Voice of IBM.Through navigation experiments,navigation can be done almost without keyboard,which proved that human_computer interaction is very convenient by speech commands and the reliability is also higher.

Contact surface fatigue life for roller rack pinion system

A roller rack pinion(RRP)system,which consists of a rack-bar and a cam pinion,transforms a rotation motion into linear motion.The rack-bar has a series of roller train and meshes with the cam pinion.First,the exact tooth profile of the cam pinion and the non-undercut condition to satisfy the required performance have been proposed with the introduction of the profile shift coefficient.Then,the load stress factors are investigated under the variation of the shape design parameters to predict the gear surface fatigue limit which is strongly related to the gear noise and vibration at the contact patch.The results show that the pitting life can be extended significantly with the increase of the profile shift coefficient.

Quality-Oriented Facade Systems： Initial Investments vs. Global Cost Approach

An analysis applied to an existing building considering the whole service life, regulated or, if any, measured, of energy/technological upgrading action does not only require initial investments to be taken into account. Of course, such investments are significant and will have to be considered at a first stage, but it is not the only aspect to be considered. Provisions of Construction Procurement Guidance, No.7 Whole Life Costs state： ＂All procurement must be made solely on the basis of value for money in terms of the optimum combination of global costs--and not only initial investment costs--and quality to meet the user＇s requirements＂.

The Influence of the Concepts of Biophilia and Biomimicry in Contemporary Architecture

The contemporary demand for reducing carbon emission is changing the way architects design buildings, thus influencing a wide range of new solutions. In this paper, the author presents a method that intends to contribute for the discussion of recent strategies that lower the buildings＇ consumption of energy. The study establishes three priority parameters to analyze the faqades based on the materials, the practices and the thermal behavior. Each parameter is measured separately scaled from artificial to natural building materials, local to distant practices and insulation to inertia. The design of facades has been evolving to follow complex regulations that aim to increase the required sustainable performance of buildings. Scientific data is measurable individually by each parameter, though the cross influence between parameters raise the level of complexity. Shading systems, solar passive energy influence the measurement but the growing use of renewable energies affects the measurements of energy consumption. Each design responds differently to climatic conditions, and requires complex analyses considering the specificity of the natural environment and cultural context. The discussion makes use of scientific data that influences architectural design, the research requires a broader perception thus including cultural aspects. Recent high tech insulating systems have an effect on design solutions that characterize biophilia （human love of nature）. The wisdom of traditional local solutions tested over generations holds cultural aspects of biomimicry （nature as model）. The aim is to discuss whether the framework based on biophilia and biomimicry is useful for the research.

一座城,一碗面——盘点银川市最生活化的特色面食

宁夏人,尤其是宁夏的回族,擅长制作面食。羊肉搓面、臊子面、拉面、羊肉小揪面、鸡肉蘑菇面、青拌面、生汆面……一碗碗花样繁多、色香味美的面食,不仅是宁夏人的最爱,也成为外地人爱上宁夏的一个理由。银川的面食更是种类齐全,各具特色的面馆遍布大街小巷。每一碗面,犹如银川人的生活,看似朴实无华,吃起来却有滋有味。

Functional MRI mapping of category-specific sites associated with naming of famous faces,animals and man-made objects

Objective Category-specific recognition and naming deficits have been observed in a variety of patient populations. However, the category-specific cortices for naming famous faces, animals and man-made objects remain controversial. The present study aimed to study the specific areas involved in naming pictures of these 3 categories using functional magnetic resonance imaging. Methods Functional images were analyzed using statistical parametric mapping and the 3 different contrasts were evaluated using t statistics by comparing the naming tasks to their baselines.The contrast images were entered into a random-effects group level analysis.The results were reported in Montreal Neurological Institute co-ordinates,and anatomical regions were identified using an automated anatomical labeling method with XJview 8.Results Naming famous faces caused more activation in the bilateral head of the hippocampus and amygdala with significant left dominance. Bilateral activation of pars triangularis and pars opercularis in the naming of famous faces was also revealed. Naming animals evoked greater responses in the left supplementary motor area, while naming man-made objects evoked more in the left premotor area,left pars orbitalis and right supplementary motor area. The extent of bilateral fusiform gyri activation by naming man-made objects was much larger than that by naming of famous faces or animals.Even in the overlapping sites of activation,some differences among the categories were found for activation in the fusiform gyri.Conclusion The cortices involved in the naming process vary with the naming of famous faces,animals and man-made objects.This finding suggests that different categories of pictures should be used during intra-operative language mapping to generate a broader map of language function, in order to minimize the incidence of false-negative stimulation and permanent post-operative deficits.

Locally Inverse Semigroups with Inverse Transversals

Let S be a locally inverse semigroup with an inverse transversal S°.In this paper,we construct an amenable partial order on S by an R-cone.Conversely,every amenable partial order on S can be constructed in this way.We give some properties of a locally inverse semigroup with a Clifford transversal.In particular,if S is a locally inverse semigroup with a Clifford transversal,then there is an order-preserving bijection from the set of all amenable partial orders on S to the set of all R-cones of S.

Tailoring electrolyte enables high-voltage Ni-rich NCM cathode against aggressive cathode chemistries for Li-ion batteries

The LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(Ni-rich NCM)cathode materials suffer from electrochemical performance degradation upon cycling due to detrimental cathode interface reactions and irreversible surface phase transition when operating at a high voltage(≥4.5 V).Herein,a traditional carbonate electrolyte with lithium difluoro(oxalato)borate(Li DFOB)and tris(trimethylsilyl)phosphate(TMSP)as dual additives that can preferentially oxidize and decompose to form a stable F,B and Si-rich cathode-electrolyte interphase(CEI)that effectively inhibits continual electrolyte decomposition,transition metal dissolves,surface phase transition and gas generation.In addition,TMSP also removes trace H_(2)O/HF in the electrolyte to increase the electrolyte stability.Owing to the synergistic effect of Li DFOB and TMSP,the Li/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) half cells exhibit the capacity retention 76.3%after 500 cycles at a super high voltage of 4.7 V,the graphite/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)full cells exhibit high capacity retention of 82.8%after 500 cycles at 4.5 V,and Li/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)pouch cells exhibit high capacity retention 94%after 200 cycles at 4.5 V.This work is expected to provide an effective electrolyte optimizing strategy compatible with high energy density lithium-ion battery manufacturing systems.

Anion exchange membranes based on long side-chain quaternary ammonium-functionalized poly(arylene piperidinium)s for vanadium redox flow batteries

A new series of poly(arylene piperidinium)-based anion exchange membranes(AEMs)are proposed for vanadium redox flow batteries(VRFBs).The AEMs are fabricated via the Menshutkin reaction between poly(arylene piperidine)without ether bonds in the backbone and various quaternizing agents,including iodomethane,1-bromopentane,and(5-bromopentyl)-trimethylammonium bromide.The properties of the AEMs are investigated in terms of sulfuric acid doping content,swelling,vanadium permeability,ion selectivity,area-specific resistance,mechanical properties,VRFB performance,and cyclic testing.Particularly,a method of measuring the H^(+) permeability of the AEM is developed.It demonstrates that the poly(p-terphenyl-N-methylpiperidine)-quaternary ammonium(PTP-QA)membrane with a QA cation-tethered alkyl chain exhibits high H^(+) permeability,resulting in low area resistance.Combined with its low vanadium permeance,the PTP-QA membrane achieves nearly 370 times higher ion selectivity than Nafion 115.The VRFB based on PTP-QA-based AEM displays high Coulombic efficiencies above 99% at current densities of 80-160 mA cm^(-2).The higher energy efficiency of 89.8% is achieved at 100 mA cm^(-2)(vs.73.6% for Nafion 115).Meanwhile,the PTPQA-based AEM shows good cycling stability and capacity retention,proving great potential as the ion exchange membrane for VRFB applications.

Enhanced emission at 2.85 μm of Ho^(3+)/Pr^(3+) co-doped α-Na YF_4 single crystal

The Ho^(3+)/Pr^(3+) co-doped Na YF4 single crystals with various Pr^(3+) concentrations and constant Ho^(3+) molar percentage of ~1% were grown by an improved Bridgman method.Compared with the Ho^(3+) single-doped Na YF4 crystal,an obviously enhanced emission band at 2.85 μm is observed under 640 nm excitation.The Judd-Ofelt strength parameters(?2,?4 and ?6) are calculated,the radiative transition probabilities(A),the fluorescence branching ratios(β) and the radiative lifetime(τrad) are obtained in the meantime.The energy transfer from Pr^(3+) to Ho^(3+) and the optimum fluorescence emission of Ho^(3+) ions around 2.85 μm are investigated.Moreover,the maximum emission cross section of above samples at 2.85 μm is calculated to be 0.72×10^(-20) cm2 for the Na YF4 single crystal with Ho^(3+) molar percentage of 1% and Pr^(3+) molar percentage of 0.5% according to the measured absorption spectrum.All results suggest that the Ho^(3+)/Pr^(3+) co-doped Na YF4 single crystal may have potential applications in mid-infrared lasers.