bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanical behaviour of slenderness CFST filled with DCLs under axial compression
Authors: Zhang Huifeng , Bai Xue
Published: February 2020

The demolished concrete lumps (DCLs) has been demonstrated to replacement partial coarse aggregates when casting concrete. The experimental studied involved 12 CFST columns. Each columns diameter was 159mm, the length of specimens was 2000, 2200 and 2400 mm. The Diameter-to-thickness (D/t) ratio was 79, 53 and 40. The replacement ratio of FC by DCLs was 0, 20, 40 and 60%. Test results indicated that the slenderness ratio was the most sensitive factor on the bearing capacity of slender columns under axial compression, followed by D/t ratio, and the DCLs replacement ratio was smallest factor. The ultimate bearing capacity decreased slightly with increasing DCL replacement ratio.
Sensitive behaviour of slenderness CFST filled with DCLs under axial compression
Authors: Zhang Huifeng , Cong Junping
Published: February 2020

The demolished concrete lumps (DCLs) has been demonstrated to replacement partial coarse aggregates when casting concrete. The experimental studied involved 12 Concrete-Filled Steel Tube (CFST) columns. Each columns diameter was 159mm, the length of specimens was 2000, 2200 and 2400 mm. The Diameter-to-thickness (D/t) ratio was 79, 53 and 40. The replacement ratio of FC by DCLs was 0, 20, 40 and 60%. Test results indicated that the slenderness ratio was the most sensitive factor on the bearing capacity of slender columns under axial compression, followed by D/t ratio, and the DCLs replacement ratio was smallest factor. The ultimate bearing capacity decreased slightly with increasing DCL replacement ratio..
A Mobile Robot Path Planning Scheme for Dynamic Environments
Authors: Li Kene , Mo Qiaoliang , Zhang Zeng , Liu Bei
Published: February 2020

This paper proposes a four-direction search method for obstacle avoidance of mobile robots, and the collision energy of obstacles is modeled based on the neural network. For comparison and discussion purposes, the different invariant step lengths are tested in the static environment. To take the advantages of the large and small step lengths effectively, a variable step length method is adopted to improve the performance, such as less iteration number and lower total energy. The variable step length method is also applied to the dynamic environment to explore the real-time performance for path planning. Simulation results demonstrate the effectiveness and practicability of the presented scheme.
Modification of the prediction model of the tensile strength of short fiber reinforced polymer composites
Authors: Zhu Z H , Zhang N , Zhang Y , Hao M Y , Wu H W
Published: February 2020

Based on the defect of COX model, the parameters related to the interface properties were introduced, and the fitting results were modified to be closer to the measured values.
Improvement in microstructure and properties of MgO-C refractory by addition of Fe
Authors: Liang Wanting , Deng Shijie , Zhou Zhihong , Li Xiaoyong , Xu Lei
Published: February 2020

In order to achieve self-repairing of MgO-C refractory in oxidizing atmosphere at high temperatures, Fe powder, serving as both antioxidant and direct-bond former, was introduced into this refractory. The effect of Fe addition on the microstructure, properties and oxidation resistance was investigated. The coexistence of (Mg,Fe)Oss and Mg(Fe1.2Al0.8)O4 was identified for the Fe-containing MgO-C refractory after graphite was oxidized, by which a network was formed in the matrix. As a consequence, both densification and direct-bond in the oxidized layer were greatly enhanced compared with the conventional MgO-C refractory, solving the issue of strength degradation during high temperature oxidation. An excellent oxidation resistance was obtained owing to the above improvements.
Surface Roughness Prediction in Grinding Process of the SKD11 Steel by using Response Surface Method
Authors: Hong Son N , Duc Trung D , Nguyen Nhu-Tung
Published: February 2020

This study was performed to to develop a surface roughness model in the grinded process by using the response surface method (RSM). The experimental research was performed in the grinding the SKD11 steel by using CBN grinding wheel (symbol of HY-180x13x31.75-100#). The experimental matrix was developed basing on the Box - Behnken plan with 15 experiments. Experimental results were analyzed by Minitab 16 statistical software to develop a surface roughness model. The proposed model is a quadratic function of the grinding parameters such as workpiece velocity, feed rate, and depth of cut. The model of surface roughness was verified by experimental with very consistent results. The proposed model can be used to calculate the surface roughness values of the machined part in machining process the SKD11 steel by using CBN grinding wheel.
Surface Temperature Prediction of Asphalt Pavement Based on GBDT
Authors: Qiu X , Xu W Y , Zhang Z H , Li N N , Hong H J
Published: February 2020

Asphalt is a temperature sensitive material, distribution characteristics and vary rules of asphalt pavement temperature have an important impact on the bearing capacity and performance of pavement, which is a concern of domestic and foreign researchers. The objective of this study was to explore the correlation between pavement temperature of asphalt pavements and meteorological factors and implement an accurate trend prediction of the asphalt pavement temperature. First, errors and missing data in the meteorological dataset were cleaned. Then, the three kinds of temperature prediction models of asphalt pavements in winter were established by Gradient Boosting Decision Tree (GBDT), Random Forest (RF) and Linear Regression (LR). The results indicate that GBDT would perform an excellent ability on prediction. The mean-square-error of the GBDT predicting results has a lower value of 1.5 when compared with the Random Forest and Linear Regression owing to the high robustness and the good generalization ability, which reflects the GBDT model has a good applicability in the field of prediction. The research would serve as a technical support for the machine learning algorithms applied in the field of the application of prediction problems.
Kinematic synthesis of a reconfigurable robot manipulator with lattice morphing mechanisms based on enhanced QPSO
Authors: Yin Bo , Zhao Zhenyu , Xiao Haibing , Liu Mingjun , Hu Wen
Published: February 2020

A kinematic synthesis approach of a modular reconfigurable robot manipulator with lattice morphing mechanisms is proposed to find the optimal robot configuration with the minimum weight. First, the structure features and types of lattice mechanisms are introduced. Then, a synthesis approach using an enhanced QPSO (Quantum-behaved Particle Swarm Optimization) to get the optimal robot configuration with the minimum lattice is presented. Finally, a computation example is given to show the optimization process. The obtained results demonstrate the feasibility of this approach.
Study on dynamic behaviors of a breakwater triggered by earthquakes
Authors: Lai Jie , Liu Yun , Wang Wei , Gao Chen-qiang , Niu Zi-rong , Zhu Hai-bo
Published: February 2020

To ensure the safety requirement of an artificial island in the construction period, the modified Hardin-Drnevich dynamic constitutive model and strength reduction method was used to analyze the dynamic response of a breakwater under the action of earthquakes. Research indicates the following: (1) the modified Hardin-Drnevich can effectively simulate the soil stress-strain relationship under dynamic action, and obtain strain hysteresis, and get permanent deformation of material; (2) the deeper the buried depth of breakwater, the greater soil pressure; (3) dynamic pressure response is more obvious on both sides of the breakwater at peak time in earthquakes.
An improved pretreatment method for the fabrication of Cu-Ag core-shell nanoparticles
Authors: Zou Q Y , Yang G N , Wang P Y , Zhang Y , Cui C Q , Zhang K
Published: February 2020

A pretreatment method of nitric acid pickling is applied in the fabrication of Cu-Ag core-shell nanoparticles. By tuning the pH value and the concentration of Cu ions after acid pickling, the cleaning and separation process can be eliminated. This simplified pretreatment process can prevent the oxidation and particle loss. The as-prepared Cu@Ag nanoparticles show promising coating quality, oxidation resistance and quasi-spherical core-shell microstructure. Such a pretreatment method provided by this study could be promising in further rapid fabrication of Cu-Ag core-shell nanoparticles.
Research Status of Ultrasonic Vibration Assisted Plastic Forming Process
Authors: Chen Zhanbin , Yang Lianfa , Zhang Kunyan , Jiang Jingyu , Zong Pengju
Published: February 2020

Ultrasonic vibration assisted plastic forming is a process method for assisting the forming of metal materials by means of ultrasonic vibration devices. It is proved that the ultrasonic vibration could reduce the forming force, improve the friction environment, and enhance the formability of the metal material. However, there are some differences in forming characteristics for different materials under different vibrational plastic forming processes. In this paper, the forming principles, the vibration application modes and the forming characteristics of the ultrasonic vibration assisted the wire drawing, equal channel angular pressing (ECAP), upsetting, drawing of the sheets and hydroforming of the tube are reviewed. It emphasizes on the various processes’ improvement of the forming efficiency and the quality of the formed parts under the aid of ultrasonic vibration. Finally, the future development trend of ultrasonic vibration assisted plastic forming was prospected.
Experimental Study on Continuous Laser Polishing Die Steel S136D
Authors: Zhao Zhen Yu , Zhang Zhen Jiu , Yin Bo , Xu Xiao Mei
Published: February 2020

With the traditional polishing method the mold material will cause problems such as difficulty in processing the micro-area surface and damage to the surface of the workpiece. Laser polishing technology is an advanced and new surface processing technology that has emerged in recent years. Because laser polishing has the characteristics of good polishing quality and low thermal effect, it is very suitable for high-precision polishing of mold steel, titanium alloy and other materials. By properly controlling the process parameters such as laser energy density, scanning speed, scanning pitch and defocusing amount during laser polishing, the workpiece can be polished with high precision and the surface roughness can be quickly reduced. The processing examples in the paper further illustrate the superiority of laser polishing.
Improvement of physical, mechanical and strength behavior of cohesive soils with natural pozzolana and brick dust
Authors: Chang E , Villalta J , Fernandez C , Duran G
Published: February 2020

This research project seeks to improve soil properties through experimentation with geotechnical purposes. For this, will be used natural volcanic pozzolana in 5%, 10%, 15% and brick dust in 10% giving it a second reuse. The soil improvement will be analyzed with the proposed additions and its influence on the results. It is concluded that the addition improves the behavior of the soil by decreasing its plasticity index, increases the compaction index and improves the geotechnical parameters.
Use of recycled broken bricks as Partial Replacement Coarse Aggregate for the Manufacturing of Sustainable Concrete
Authors: Pinchi S , Ramírez J , Rodríguez J , Eyzaguirre C
Published: February 2020

The bricks are one of the primary materials required for construction of homes that no used completely when executes all the walls due, the excess purchase, the cutting to be settle, the breaking for their transfer and its fixed dimensions; this situation requires monitoring on work site the order, cleanliness and accidents. A common practice is these bricks and/or waste are included in the clearing construction before being deposited or eliminated in dumps or sanitary landfills, with their early clogging and shortening them to ther design lifespan. An important alternative to reduce this waste, is to recycle them and reuse them as a concrete component material, due to their high absorption percentage that allows them to keep the water inside of them and then use it in the cement hydration process as internal curing of the concrete. In the present investigation, the effect of crushed clay brick as a replacement for coarse aggregate in concrete processing is studied. The results indicate that with 21 % replacement brick, the plastic contraction decreases, and the compressive strength and flexural strength increase.
Productivity improvement of tower crane in tall buildings
Authors: Manrique A , Saman J , Rodriguez S , Melendez K
Published: February 2020

The tower crane is an electromechanical equipment that is used for the vertical transport of materials in a construction project and together with the two riggers form the work team to carry out this task. One of the main problems in the construction of multifamily buildings corresponds to the use of the tower crane because vertical transport causes non-contributory times, which is, dead times and waits above expectations. This research analyzes the current vertical transport process and proposes its optimization through some management tools with the aim of improving the productivity of the use of the tower crane by reducing non-contributory times. To this end, the productivity of the work team is recorded in several projects with similar characteristics, then the main problems are selected to analyze them and finally the process is optimized. The results determined that non-contributory times can be reduced by 10% if there is an orderly and continuous process.
Numerical simulation of the plunge stage of friction surfacing of AA5083 aluminum alloy
Authors: Li Hongjun , Xu Zhuang , Zhou Zhewei
Published: February 2020

Plunge stage is crucial to the success of whole friction surfacing process. To investigate the effect of parameters, the CEL modelling method in the finite element software model was used to simulate the plunge stage of friction surfacing. The results showed that the higher rotation speed would result a smaller axial force but higher the center point temperature and frictional dissipation; Besides, a higher feed rate, who can cause higher peek value of axial force and the center point temperature rises faster, is inversely proportional to the frictional dissipation, and the final axial force and the center point temperature tended to be in the same range.
Eco-Concrete for Hydraulic Structures with Addition of Colloidal Nano-Silica
Authors: Salguero C , Castañeda L , Rodríguez J , Carrera E
Published: February 2020

In the construction of buildings and infrastructures, high resistance materials are used due to current design requirements, concrete being one of the main materials used in the execution of these projects whose cement content is limited to obtaining an economic concrete and of minimum retraction. This limitation requires the use of new additions such as Nano Silica (NS), which due to its nanometric structure is used as a partial replacement for cement, producing an increase in strength in concrete. The present investigation studies the partial replacement of the NS in the cement to determine its behavior in compressive strength, diametric compressive strength, water permeability coefficient. The results indicate that with an addition of 0.225% of NS the compressive strength and splitting tensile strength are increased and the water permeability coefficient decreases, all of them compared to a conventional concrete.
Short Review of Polymer Composites for 3D Printing
Authors: Zhu Z H , Zhang N , Wang T , Hao M Y
Published: February 2020

3D printing technology is a rapid prototyping technology, which can use different materials to prepare real objects through layer by layer printing based on three-dimensional digital model. At present, the material with the largest amount of application and the most extensive molding method is polymer material. The research of ABS, PLA, PCL, TPU, photosensitive, resin polymer hydrogel and their composites are reviewed in this paper.
Methodology for determining optimized traffic light cycles based on simulation
Authors: Rivera G , Velasquez L , Bravo A , Miñano P
Published: February 2020

In large urbanized cities, a major problem that affects the economy and health of all citizens is vehicular congestion. This is because the traffic light cycles are not adequate. In the present study, we seek to optimize traffic light cycles based on simulation, in order to improve vehicle flow. For this, the PTV Vissim 9.0 software was used as a simulator and the Synchro 10.0 software to determine the initial optimal traffic light cycle. Through several runs and having as variables the length of queues, delay times and the average speed, the optimal traffic light cycle could be found for the study area. The results obtained reflect a 14% reduction in delay times and 10% in queue lengths. On the other hand, the average vehicle speed increased by 10.56%. All this represents an improvement in the service level of the study intersections.
A 3-D Analysis on the Loading Behaviours of an Under-reamed Anchor in Cohesion-less Soils
Authors: Hsu Shih-Tsung , Chen Xiang-Yang , Wang Yi-Fan
Published: February 2020

This study adopts a constitutive model for sand and a 3-D numerical software, named “FLAC3D” to examine the anchorage behaviours of an under-reamed anchor in sandy soil. A series of pull-out test on model anchors is performed to confirm the results obtained numerical analyses. Test results reveal that the load-movement curves computed numerically are get close to those estimated experimentally. For under-reamed anchors with dimensions of D=0.075m, L/D=4.5, and installed in sandy soil of Dr=70% (Dr: relative density, D: diameter of anchor, L/D: fixed end/diameter ratio), the shape of load-movement relationship on a deep anchor differs from that of a shallow anchor, especially the shape of end resistance-movement curve. However, the friction force, end resistance and total load do not attain peak values at same anchor movement. The end resistance of a shallow anchor displays obviously peak value. However, the peak value the end resistant cannot treasured from a deep anchor. The friction load presents peak and residual values. The mainly pull-out load of a shallow anchor is donated by the friction load, meanwhile the end bearing governs the pull-out load of a deep anchor; overburden depth of 12D is the shallow/deep anchor demarcation. According to the definition of end bearing coefficient, it is categorised to a deep anchor as the overburden surpasses 12D, it is a shallow anchor if the overburden is smaller than 7.5D, and as the overburden equal to 7.5D∼12D, the anchor can be classified as a transit anchor.
Re-liquefaction of Sand in Shaking Table
Authors: Nepal Dikshit Babu , Deng Jianliang , Chen Jinjian , Maakoe Tshegofatso
Published: February 2020

Subsequent aftershocks can induce reliquefaction of sand. In the shaking table experiment, the settlement, the excess pore water pressure and the acceleration response of the sand in the process of reliquefaction were measured. It was found that: (1) the liquefaction resistance of sand was the lowest in the second liquefaction, not in the first liquefaction; (2) Liquefaction resistance is depth-dependent, and the soil layer near the surface of soil is most likely to be liquefied; (3) In the model test, the attenuation of seismic shear wave acceleration is not only related to distance but also to the vibration frequency and to the liquefied layer; (4) The amplitude of the acceleration response increases with the number of the shaking. This result indicates that: (1) the phenomenon of re-liquefaction of sand induced by earthquake is not same as that of the first liquefaction. Therefore, the conventional strategy for liquefaction resistance needs to be improved before it can be implemented for analysis of reliquefaction. (2) The attenuation of seismic shear waves in liquefied soil layer has some properties different from the normal soil layer; thus the traditional attenuation calculation method needs improvement in the evaluation in the analysis of site liquefaction.
Effect of End-to-End Connectors in Elastic GFRP Gridshell
Authors: Baral Kedar , Cheng Bin , Xiang Sheng , Sharma Suraksha
Published: February 2020

The presence of end-to-end connectors for lengthening the glass fiber reinforced polymer (GFRP) pipes in elastic gridshell causes imperfections in the structure. Such geometrical imperfections alter the structural properties of members and affect the overall performance of the structure. Hence, for a comprehensive analysis of such structures, the aforementioned imperfections need to be acknowledged. In this study, an equivalent rigid part (ERP) for the connector was proposed for taking into account the effect of connectors in the structural analysis. The applicability of ERP for predicting the deformation of structural members was first verified by bending beam models. A typical GFRP elastic gridshell was further utilized for investigating the effects of connectors (with two different arrangement) in the shape and stress of the structure. Results show that proposed ERP is practicable for simplifying the end-to-end connectors in the structural analysis model. Significant differences in results were found between the analysis with and without the consideration of end-to-end connectors, and therefore the effect of connectors should be considered during structural analysis of elastic gridshell.
Investigation of process for producing carbide-containing welding fused fluxes using plasma granulation
Authors: Artemov A O , Naumov S V , Ignatov M N , Belinin D S
Published: February 2020

This article proposes a technology for producing fused welding fluxes using plasma granulation. The developed technology enables producing welding flux granules with carbide-containing additives. This is possible due to high dynamic and temperature effects of plasma arc on mineral raw materials that stops refractory additives from melting and thus remaining in welding materials composition. Using petrographic analysis, it was found that silicon carbide particles remain unchanged in granules of fused welding fluxes composition. Plasma granulation technology makes it possible to obtain both finished products such as welding fluxes and a charge ready for manufacturing cored wire and coated electrodes.
Obtaining welding materials of various structures, fractional and chemical composition using plasma granulation
Authors: Naumov S V , Artemov A O , Kartashev M F , Sheksheev M A
Published: February 2020

The article proposes the technology for producing fused welding fluxes grains of various structures, fractional and chemical composition using a highly concentrated heat source. Interaction processes between the highly concentrated heat sources and mineral raw materials are presented in the article. The necessary components for obtaining welding flux with various granule structures are determined. The proposed technology allows to obtain welding flux granules with a range from 0.1 to 3.0 mm that meets regulatory documentation requirements. It was found that during the process of plasma granulation there is a decrease in the concentration of alkali metals to the required content for welding fluxes. At the same time, there is an increase in the concentration of basic elements such as silicon, calcium, aluminum and other metals
Mechanical properties and self-cleaning mortar capacity C/A 1: 5 of Portland cement modified with titanium dioxide (TiO2)
Authors: Flores H , Bernuy G , Huerta C
Published: February 2020

The deterioration of the surfaces of the constructions made with mortar C/A 1: 5 of Portland cement, are produced by being exposed to the emission of toxic gases emanating from the growing automobile fleet, this problem causes alternatives to be sought in order to counteract its effect on buildings and the environment. A new method to deal this problem is the incorporation of the titanium dioxide photocatalyst (TiO2) into the Portland cement mortar, which can develop self-cleaning and air purification properties to be in contact with sunlight. This work seeks to introduce this organic component to the Portland cement mortar, used for the facade charging and structural elements, for this purpose, different percentages (5%, 7.5% and 10%) of titanium dioxide (TiO2) are added and the properties of the modified mortars making use of [1] compression tests, [2] fluidity tests, [3] absorption tests and [4] photocatalytic activity tests with which the self-cleaning capacity was verified. This study concludes that the best percentage of titanium dioxide addition is 5%, with which the Portland cement mortar is granted self-cleaning property without substantially damaging its mechanical properties.
Finite element analysis and experimental study on laser welding temperature field of dissimilar metal materials
Authors: Xiao Haibing , Zhang SongLing , Zhou Yongquan , Xu Xiaomei , Luo Bowei
Published: February 2020

Aiming at saving defects and cracks of dissimilar metal materials laser welding, the finite element analysis of temperature field and new welding process of stainless steel/Al, stainless steel/Cuwere developed in this work.Taking stainless steel/Al, stainless steel/Cu dissimilar materials laser welding for example, the physical model was established, and the finite element simulation of three-dimensional temperature field of laser welding was carried out based on Abaqus CAE. The results show that the simulation of temperature field provides reference for experimental process parameters, fiber laser welding is applicable to stainless steel/Cu, stainless steel/Al with lower laser welding defect.The process parameters were optimizedto achieve better welding quality and solve welding defects.The accurate prediction of temperature field distribution in dissimilar materials laser welding is great significance for practical process guidance.
Cooling performance improvement of circulating internal cooling turning tool by built-in additional spray cooling nozzle
Authors: Shu Shengrong , Zhang Yu , Xiao Caiwei , Qi Xiaoning , Liu Leping
Published: February 2020

Aiming at the demand of high efficiency green cooling cutting of difficult-to-machine materials, a novel composite cooling turning tool design concept based on circulating internal cooling combined with spray cooling is proposed in this paper. Thermal-fluid-solid coupling simulation models were developed based on FLUENT software, which are applied to investigate the cooling performance of two type of composite cooling tool which are single-nozzle type and double-nozzle type, and the circulating internal cooling tool. Simulations results shown that the tool-chip interface temperatures of the three tools are from low to high under the same conditions, followed by the composite cooling turning tool with double-nozzle, the composite cooling tool with single-nozzle and the circulating internal cooling tool. The double-nozzle type of the composite cooling tool exhibits a better cooling and lubrication performance.
Effect of Quartz Sand on Compressive Strength of High Performance Basalt Fiber Concrete
Authors: Dongdong Yao , Hongru Ji , Zhe Lu , Xinjun Li , Jie Li , Zhengang Feng
Published: February 2020

The QS with different sizes was used to prepare the HPBFC according to the closing packing theory. The universal mechanical tester was applied to test the compressive strength of HPBFC specimens after different curing periods. Effects of the QS with different sizes and mixing ratios on compressive strength of the HPBFC were compared and the development of compressive strength of the HPBFC during different curing time was analysed. Results show that the QS with small particle size can significantly increase the compressive strength of HPBFC. The HPBFC with small size of QS not only possesses the highest compressive strength at different curing stages, but also has the fastest increasing rate during the standard curing conditions.
A regenerative chatter observer analysis for micro-milling
Authors: Liu Di , Liu Xiaoli , Pei Xuming , Wang Caidong , Chen Lumin
Published: February 2020

The regenerative chatter in micro-milling that is employed to produce small products with complex 3D geometries and high precision is gradually getting attention from researchers in the field of manufacturing, mechatronics and control for its severe damage to the cutting tool and micro-milling stability. To facilitate developing observer-based control strategy for suppressing the regenerative chatter, the integrating an adopted observer proposed for nonlinear systems with time delay and a practical regenerative chatter model for micro-milling is presented in this paper. And the observer analysis is shown. Simulation results are given to validate the integration scheme.
Experimental and numerical investigation of cold roll forming process
Authors: Murugesana Mohanraj , Sajjadb Muhammad , Jung Dong Won
Published: February 2020

This research work is focused on the cold roll forming process to produce U-channel from the flat sheet. The mechanical properties of aluminum alloy was obtained from the tensile test and subsequently, the properties were incorporated into LS-DYNA to define the material plastic region. The forming process involves the progressive sheet deformation by passing it through a roll pass at constant roll speed. Each sets are designed at different bending angle to increase the deformation until the final geometry is achieved and here, the forming machine with four roll stands were used to manufacture the parts. As a sheet is going into different passes at the same time, the sheet plastic deformation is so complex and highly non-linear because of various stress and strain developments. From experimental results, at low roll speed (RS) the longitudinal bow was observed in the formed parts and to investigate, numerical simulation was modeled at various roll speed and found that as roll speed increasing the longitudinal bow noticed to be decreasing. To confirm the finite element results, one more experiment at high speed was performed and the obtained results showed better agreement with the simulation results. Before confirming the accuracy, many issues were encountered and modified such as mesh size at roller and blank, contact mechanism, choosing element formulation and friction coefficient. Furthermore, the adaptive meshing procedure was adopted to efficiently remesh the sheet at contact locations. The research procedures presented can be utilized to perform the forming process for any existed or new material to form a desired shape for a specific applications in the automobile and aerospace industries.
FM analysis of aging properties of UV531/SBS modified bitumen
Authors: Zhengang FENG , Fengjie CAI , Dongdong YAO , Xinjun LI
Published: February 2020

Ultraviolet absorber UV531 and linear SBS modified bitumen were selected to prepare SBS modified bitumen via melt blending. Thermal-oxidative and ultraviolet (UV) aging of SBS modified bitumen were simulated by the film oven test (TFOT) and accelerated UV aging. The influence of UV531 on the micromorphology of SBS modified bitumen before and after aging was analyzed by fluorescent microscopy (FM). Combined with the three indicators and aging properties of modified bitumen, the relationship between microstructure and properties of SBS modified bitumen and UV531/SBS modified bitumen was discussed. The FM images show that the UV531 improves the thermal-oxidative aging property of SBS modified bitumen, but it has little effect on UV aging.
Investigation of bow defect in roll forming
Authors: Sajjada Muhammad , Murugesanb Mohanraj , Jung Dong Won
Published: February 2020

Even though New materials are coming into the market Aluminum Alloy is still widely used in Aerospace, Automobile and defense industries. The main reason is these alloys are light weight, high strength and easy to recycle. Many traditional methods like punching, shearing and blanking has been widely used previously to deform these sheets in different industries. Meanwhile, roll forming which is die less processing method, has been used for manufacturing of parts for automobiles and aircrafts structure parts. In this paper, combination of numerical simulation and experimentation of Aluminum alloy 5052 for bow reduction has been studied for U-shape sections. From results it was concluded that the bow defect is significantly reduced by increasing the forming speed of forming rollers.
Effect of early strength agents on specified density concrete
Authors: Yan Shuaishuai , Zhang Ming
Published: February 2020

Early strength agents are beneficial to improving early strength of concrete, thereby shorting curing time as well as production efficiency of concrete products, and consequently saving production costs. This study investigated the influence of triethanolamine, potassium carbonate, Calcium formate and Potassium aluminum sulfate on properties of specified density concrete, based on orthogonal experiment, composite early strength agent is determined.
Influence of Cr3+ Doping on Photocatalytic Hydrogen Production Performance of TiO2 Film Growing in Situ on the Surface of Ti Plate
Authors: Bai Xuefeng , Wu Wei
Published: February 2020

The Cr3+ doped TiO2 films (Cr@TiO2) were prepared by in-situ growing on the pure Ti plate substrate in the electrolyte solution of Na3PO4 containing a certain amount of K2Cr2O7 using micro-arc oxidation (MAO) technique. The Cr@TiO2 were characterized by SEM, XPS, XRD and DRS. The influence of Cr3+ doping amount on the morphology, structure and photocatalytic hydrogen production performance of Cr@TiO2 was studied. The characterization results showed that Cr3+ doping into TiO2 film not only affects the crystallinity of TiO2, but also affects the composition of crystal phase, and the maximum absorption edge of Cr@TiO2 reflects an obvious redshift, reaching around 650 nm of visible light with the increase of Cr3+ content. The Cr3+ doping was good for the improvement of photocatalytic performance. The Cr@TiO2 prepared under the condition of K2Cr2O7 adding amount of 0.29 g/L exhibited the highest rate of 0.378 mol/cm2•h
Improved mechanical properties of a high plasticity clay soil by adding recycled PET
Authors: Alvarez A , Sosa J , Duran G , Pacheco L
Published: February 2020

To the problems posed by clay soils of high plasticity, such as vulnerability to variations in volume, producing differential settlements causing damage to structures, it is due to factors such as this it was decided to seek an alternative enhancement to parameters such as increased resistance, friction angle and cohesion of a high plasticity clay soil (CH). In the execution of civil works, these parameters generally do not conform to the requirements of the project, for that reason should seek a solution for the stability of the soil involved in any construction. The constant search for improving environmental conditions has led to the use of waste plastic to reinforce the soil and improve its mechanical and physical properties. That is why according to our proposal we try to increase data for the use of this alternative material as a soil improvement proposal, obtaining interesting and different results to that found in other investigations that used similar materials. We chose crushing polyethylene terephthalate (PET) obtaining a recycled PET 3-5 mm length as a reinforcing material to stabilize and improve the mechanical properties of the soil. According to standard proctor assays and direct shear, it was determined that the optimum percentage to be added is from 1% to study the soil because of better behaviors were observed study material with respect to the other mixtures.
Research of elevator real time monitoring method based on spark
Authors: Jianpeng Huang , Xiyang Jiang , Yifei Tong , Feng Gu
Published: February 2020

With the development of economy, elevator has become one of the essential means of transportation in people’s life. However, due to the complexity of the elevator internal system, the sensors collect a large number of elevator operation data so that the reliability and real-time of data processing is very important for the safety monitoring of elevator operation. To solve this problem, this paper proposes an elevator real-time monitoring method based on spark. By using the stream data processing method provided in spark streaming, a large number of real-time data are divided into time windows, the data is divided into small batches of data below the second level and submitted to spark engine for analysis and processing, which greatly improves the speed and throughput of data processing.
The research status of key problems of experimental equipment for tube hydroforming
Authors: Zhang Kunyan , Yang Lianfa , Chen Zhanbin , Huang Jinjie , Ma Jianping , Zong Pengju , Jiang Jingyu , Liu Jun , Li Xianzhang
Published: February 2020

Tube hydroforming technology is an advanced manufacturing technology adapted to lightweight structure. The technology has the advantages of low production cost, high material utilization rate and light part quality. Forming equipment is the basis for implementing the technology, the performance of the equipment greatly affects the product quality. However, the key problems affecting the performance of the equipment include: loading path, axial feeding and sealing method, etc. The article is for the purpose of key question carrying on the system combing with the discussion. Among them, several hydraulic pressure control methods are summarized, the influence of different loading path on tube hydroforming is shown, A loading method that axial stress - circumferential stress is always proportional in the forming process is proposed. Meanwhile, the control method of axial feed is summarized, it is expressed that axial feeding can improve tube forming ability. Besides, five kinds of common pipe sealing methods were compared, the reliable and effective sealing structure is summarized.
Synthesis of SAPO-41 Molecular Sieves with Different SiO2/Al2O3 Ratios and their Catalytic Performance of n-Decane Hydroisomerization
Authors: Wang Han , Guo Chunmu , Meng Jinying , Li Ting , Luo Le , Wang Quan , Wu Wei
Published: February 2020

Using di-n-propylamine (DPA) as a template, SAPO-41 molecular sieves with SiO2/Al2O3 ratios (n) of 0.3, 0.5, and 0.7 were synthesized. Their structure, morphology and acidity were characterized by XRD, N2 physical adsorption, SEM, and Py-IR. All the synthesized samples have characteristic diffraction peaks corresponding to the AFO topological structure, which means that samples are pure phase SAPO-41 molecular sieve. The samples exhibited a highly ordered prismatic morphology with regular arrangement of individual grains, wrapped in flakes, and possessed complete channel structure. With the increase of n, the specific surface area and the amount of B acid showed a downward trend after increasing. Hydroisomerization reaction results of n-decane over SAPO-41 loaded with 0.5wt% Pd (Pd/SAPO-41(n)) showed that the higher the amount of B acid, the higher the conversion of n-decane,and high specific surface area and moderate B acid are favorable for yield of isomerization products. When the conversion of n-decane catalyzed by Pd/S41(0.3)-P was 88.9%, the yield of hydroisomerization products reached 83.3%.
Roughened bed stilling basin and its hydraulic jump characteristics
Authors: Liu Yakun , Zhang Di , Wu Jian , Zhang Dong , Yang Miaomiao
Published: February 2020

The roughened-bed stilling basin, serving as one new type of energy dissipator, has been analyzed both theoretically and experimentally in the literature. This study deduces the calculation formula of the length of the curve C0
between the flow-depth contraction section (i.e. hc) and the section just before the hydraulic jump (i.e. h1) when the same elevation is employed for both the bottom of roughened-bed stilling basin and the river-bed surface in the downstream. Further, by approximately assuming the equation of the resistance force exerted on the flow and caused by the bed roughness, this study obtains the expression of the ratio between the flow depth before the hydraulic jump and that behind the hydraulic jump, namely h1/h2. With the aid of the experimental results in the existing literature, it can be concluded that, when compared with the traditional smooth-bed hydraulic jump, the sequent depth and the length of the rolling hydraulic jump can be reduced by about 20∼30% and 20∼50%, respectively, in the condition of the chopping roughness riverbed. Additionally, by combining with the hydraulic model tests, this study indicates that adding the bed-roughness can eliminate the secondary hydraulic jump, improve the flow regime and (under the circumstance of the sill-roughness stilling basin) decrease the length of the stilling basin up to about 40%∼50%. Keywords: Stilling Basin; Hydraulic Jump; Hydraulic Characteristics; Roughened Bed; Sequent Depth; Energy Dissipation
Evaluation of the geotechnical behaviour of a volcanic soil wall with additions of lime and cement against landslides
Authors: Davila C , Vera R , Pacheco L , Duran G
Published: February 2020

The construction of earth walls can be a significant response to prevent the next landslides from reaching the road and avoid accidents. Therefore, a material of the same slope was used and reinforced with mixtures of lime and cement, with this same reinforced material a mechanically stabilized hypothetical earth wall (MSE) was developed. An analysis of the original slope was developed to check if there was a possible failure through its safety factor. Then, a hypothetical wall was developed with a floor reinforced with mixtures, in order to assess its overall safety factor and its maximum landslides. According to the results, in principle it was determined that the dosage M-3 / C-4-4 improves in a range of 30% to 37% the friction angle. In addition, it was found that a reinforced wall, that is to say with Lime and cement additions, presents a better behaviour. In its effect, its displacements are about 8 mm and have a global factor of 1.23.
Study and assessment of (FeCrAl) and (SiC) as candidate materials for accident tolerant fuel cladding in LWRs
Authors: Sagiroun Mamoun I A , Xinrong Cao , Ayoub Anuor A T
Published: February 2020

Iron-chromium-aluminum (FeCrAl) alloys and Silicon-carbide (SiC) are considered the best choice proposed as alternative cladding materials to replace Zirconium (Zr) alloys to improve the accidents tolerance in light water reactor (LWR) cladding which have much highly oxidation resistance in high-temperature steam than Zr alloys, which lead to maintaining high performance under normal operations and enhancing safety margins during severe accidents. In this work great results were showed in the thermo-physical properties for the candidate materials compared with zirconium.
Testing research on friction and wear performance of microstructure surface of unfolding wheel for bearing steel ball detection
Authors: Chengyi Pan , Yuanqi Tong , Guanqun Cao
Published: February 2020

The unfolding wheel of AVIKO series steel ball surface quality automatic detector is expensive and easy to wear, which seriously restricts its application and development. In this paper, the wear reason and motion form of the unfolding wheel are analyzed, the unfolding contact model is simplified reasonably, and the corresponding experimental equipment and scheme are designed. The microstructures with different shape parameters are machined on the test pieces surface by laser machining technology, and the theoretical calculation formula for the weight of wear is obtained through friction and wear tests and data fitting. The test results show that compared with the smooth test piece, the test pieces with microstructure surface can increase the friction coefficient and reduce the degree of wear, and the diamond microstructure has the best effect on reducing the wear weight. The fitted formula provides theoretical and experimental basis for the follow-up research and the design of microstructure parameters of unfolding wheel.
Influential Parameter analysis of spread GFRP stay-in-place form deformation
Authors: Tong Zhaojie , Zhang Hailong
Published: February 2020

Recently spread GFRP stay-in place forms with T-ribs have been applied to bridge engineering in China. The deformation non-uniformity of spread GFRP plates in the deck transverse direction is more significant than that of narrow GFRP plates. In order to investigate the influential parameters of deformation, a 1.8 m simply supported GFRP plate was analysed using ANSYS. The analysis results show that (1) the maximum deflection of side GFRP plates is larger than that of middle plates; (2) the maximum deflection is affected by rib thickness, plate height, rib spacing and bottom plate thickness; (3) the non-uniformity of deflection is mainly affected by rib spacing and bottom plate thickness; (4) the rib thickness has little effect on the non-uniformity of deflection, and a higher GFRP plate results in a larger non-uniformity of deflection. Based on the analysis results, some measures on improving the flexural stiffness of GFRP plates in the transverse and longitudinal directions are proposed.
Experimental analysis of the addition of rice husk ash to the clayey subgrade of a road stabilized with lime
Authors: Vizcarra S , Lujan I , Soto M , Durán G
Published: February 2020

There are many studies about how the addition of lime and rice husk ash (RHA) gives the soil a better mechanical behavior, particularly on clayey soils, where usually fine particles reach more than 75%. However, the soils with a small presence of fine particles (59-60%) do not have much research. This analysis evaluates the influence that RHA has on this kind of soil stabilized with 3% of lime. After the initial mix of soil-lime, CBR increased 11.2 times its initial value; within the addition of the ash, the CBR averaged between 45-50% up until 28% of RHA was added, where the results decreased considerably. Soil workability improved and the specimens with more ash resulted in a more granular material, with a group index value 0 following the AASHTO standards. The greatest CBR record was obtained with the specimen of 16% RHA, 3% lime and soil, reaching a 51.3% CBR, 1.58g/cm3 of MDD and 16.5% of OMC. Yet, it only showed a 1.55% more resistance than the lime-soil specimen. The CBR with more presence of RHA tends to decrease its value, therefore for silica-rich clayey soils, the addition of lime by itself should be enough for an adequate performance.
Excited State Relaxation Dynamics of Silicon Nanosheets using Time-dependent Density Functional Tight Binding Theory
Authors: Wang M Y , Wu Q
Published: February 2020

By combining time-dependent density functional tight binding (TD-DFTB) calculations for electrons with molecular dynamics simulations, time evolution of excited state relaxation and single electron self-trapping of silicon nanosheets (SinHm) are investigated. We identify the atoms and bonds contributing to the excitations and observe the time evolution of charge density, indicating the migration of exciton from initial position to neighboring bonds. Different temperature 50K and 100K are attempted in the MD simulations, and the temperature is found to affect the electronic localization. Our simulations reveal the formation of exciton trapping and localization on certain bonds upon excitation within the timescale about 200-300fs. In summary, TD-DFTB excited state MD simulations can provide interesting insights into photoreactions and have crucial implications in modulating the exciton transport efficiency in strongly confined low-dimensional systems.