Mechanical properties of Cu matrix composite fabricated by extrusion process

Carbon nanotube （CNT）was applied in various fields for itssuperior electrical, mechanical and thermal characteristics. After composites were fabricated by extrusion processusing ball-milledCu-CNT powders, mechanicalpropertiesofCu-CNT composites according to CNT fraction were reviewed. CNT （1%, 5% and 10%）,Cu （d=100 nm）, zirconia balls （90 g） and ethanol （20mL） were mixed and dispersed for5h at a speed of 500 r/minusing a planetary ball mill. A billet （d=50 mm, length=100 mm） was made with Cu, and the composite powderswerefilled up into billet using the uni-axial press. In the extrusion process, after the billet was heated at 880℃for1h, specimens were produced in the shape of a round bar using the billet by applying a load of 200 t. The composite powdersweremeasured for particle size byparticlesize distributionequipment. Then the specimen surface fabricated by extrusion was observed by SEM. Mechanicalpropertiesmeasured by the indentation equipment increased with increasing CNT content. The yield strength, tensile strength and hardness of theCu–CNTs composites canbeobviously improved.

Topological dependence of mechanical responses of solidification microstructures in aluminum brazed joints

The main objective is to provide an evidence of spatial dependence of mechanical responses of a heterogeneous aluminum brazed joint re-solidified clad, and to confirm a sufficient sensitivity of a nano-indentation—load curve method for identifying the dependence. Topological features of a network of solidification microstructures(α phase and eutectic), formed during quench in a brazing process of aluminum alloy, influence significantly dynamic mechanical responses of resulting heterogeneous material. Nano/micro indentation depth vs load characteristics of differing phases suggest a spatially sensitive mechanical response of a re-solidified fillet in the joint zone. Hence, a spatial distribution, pattern formations and other morphological characteristics of microstructures have a direct impact on an ultimate joint integrity. Topology-induced variations of indentation—load curves was presented. A hypothesis involving microstructures’ spatial distribution vs mechanical response was formulated.

Development of Instrument Control System Using Biosignals Created by the Change of Eyes Movement Sequence

A new biosi gn al control system that offers the disables the opportunities to control electric appliances is proposed.The four types of signals created by the eyes movements in four directions(up,down,left,and right),which are taken as four basic signals , are detected at the forehead.Permutation of 2 signals out of them creates 16 d ifferent signals.Permutation of 3 signals out of them creates 64 signals.They al l amounts to 84 control signals.They are thought to be applicable for the operat ion of some instruments.Furthermore,the dynamic biosignals created by the slow e yes movement is speculated to be applicable for the more convenient control of t hem.

Heuristics for Improving Operational Performance of Permutation Circulati on-type Vehicle Routing System

This paper discusses an optimization of operating a p ermutation circulation-type vehicle routing system (PCVRS, for short), in w hich several stages are located along by a single loop, and a fleet of vehicles travels on the loop unidirectionally and repeatedly. Traveling on the loop, each vehicle receives an object from the loading stage and then carries it to a cert ain processing stage, or receives an object from a certain processing stage and then carries it to the unloading stage per a turnaround. No passing is allowed f or the vehicles on the loop (from which the system is called permutation, and th is restriction may cause interferences between vehicles). Material handling systems such as PCVRS are actually encountered in flexible man ufacturing systems and in automated storage/retrieval systems. In this paper, we propose a heuristic algorithm for operating the PCVRS, which i ncorporates a new scheduling method for the vehicles with the SPT (shortest proc essing time) numbering of jobs and a round-robin manner of allocating jobs to t he stages, aiming to reduce interferences between the vehicles. We also give num erical results with respect to system performances attained by the heuristic. Description of the system The PCVRS consists of a set of n v vehicles V={V 1,V 2,...,V n v}, a set of n s, processing stages S p={S 1,S 2,...,S n s}, a loading stage S 0 and an unloading stage S n s +1. We denote by S=S p∪{S 0,S n s+l} the set of all the stages. The vehicles travel on a single loop unidirectionany and repeated ly. The system layout is depicted in Fig.1. There is a set of n jobs J={J 1,J 2,...,J n} to be processed b y the vehicles. Each job consists of two tasks: That is, each vehicle receives a n object from S 0 and then carries it to S l with a certain l∈{1,2, ...,n s} (a throw-in job), or receives an object from S l with a certain l∈{1,2,...,n s} and then carries it to S n s+1 (a throw-out job ) per a turnaround. The loop consists of buffer zones BZ(l) and travel zones TZ(l) (see Fig. 1). Each buffer zone BZ(l) is placed in front of stage S l, l=0,1,..., n s, n s+1, in order to avoid a collision between vehicles (i.e., the syste m adopts the so-called zone control strategy). A heuristic algorithm We develop a heuristic algorithm to obtain a good performance for the PCVRS. An operation π={A/B/C} for the PCVRS consists of three decision factors: (A) Numbering jobs Jobs are loaded into S 0 according to an assending order of job numbers. In this paper, we use the following rules to number jobs: SPT: Order jobs in the shortest processing time rule, i.e., P 1≤P 2≤...≤P n for the set of jobs J={J 1,J 2,...,J n}, rather than the FCFS numbering (i.e., number jobs in first-come-first-served order). The SPT rule intends to reduce interferences between two adjacent vehicles at stages. (B) Allocating jobs to stages For the purpose of balancing loads of processing stages, we adopt the following to allocate jobs to the stages: ORDER: Allocate n jobs to n s, processing stages by an in-order manner , i.e., let l(i) be the index of processing stage allocated job J i by ORDER, it holds that l(i)=n s+1-(i-[(i-1)/n s]n s).(1) The ORDER rule intends to process jobs parallel at stages as many as possible. (C) Scheduling vehicles The following method for scheduling vehicles under ORDER rule is already known: Fig.1 The vehicle ro uting system, PCVRS Fig.2 Mean turnaroun d times by heuristics Unchange: Assign n jobs to n v vehicles such that let k(i) be the i ndex of vehicle processing job J i, then k(i)= i-[(i-1)/n v]n v.(2) In csse of n v≥n s, mod (n v,n s)=0 or n v<n s, mod (n s,n v)=0 (mod(x,y) is the remainder of x/y), the number of interferences between vehicles is minimized at stage S 1 under Unchange sche dules, while in the other cases it is not [Lu et al. (2001a)]. Therefore, in t his paper, we develop a new scheduling method of the vehicles, denoted by Ex change, to modify Unchange schedules. Note

Periodic Precipitation of Liesegang System under Microwave Radiation

We studied precipitation patterns in a Liesegang system under MW （microwave） irradiation in order to investigate metal salt diffusion in an electrolyte gel. The gel and salt concentrations were varied. MW irradiation induced periodic patterns of precipitation because polar molecules vibrate and rotate in an electromagnetic field. For example, the number of patterns increased by the irradiation. Accordingly, microwave irradiation nonlinearly accelerated the diffusion of ionic molecules.

Sensitivity analysis of the vane length and passage width for a radial type swirler employed in a triple swirler configuration

The design of axial or radial swirlers typically governs a number of geometrical parameters that are determined by the desired flow field.In the meantime,the number of unknown parameters increases with the number of concentrically mounted swirlers.The available literature is nonetheless limited,and designers are obligated to increase the number of initial assumptions.In this article,three kinds of triple swirlers are employed and simulations are performed to determine the effect of each parameter on the swirler performance.Based on the correlation provided,overlengthening the radial vane length could result in significant changes in the flow field from the jetlike pattern to a wide swirl-jet angle due to the Coanda effect.Passage width should also have the potential to alter the swirl-jet angle and velocity field at the exit of the swirler.

Wear State Recognition of Drills Based on K-means Cluster and Radial Basis Function Neural Network

Drill wear not only affects the surface smoothness of the hole, but also influences the life of the drill. Drill wear state recognition is important in the manufacturing process, which consists of two steps： first, decomposing cutting torque components from the original signals by wavelet packet decomposition （WPD）; second, extracting wavelet coefficients of different wear states （i.e., slight, normal, or severe wear） with signal features adapting to Welch spectrum. Finally, monitoring and recognition of the feature vectors of cutting torque signal are performed by using the K-means cluster and radial basis function neural network （RBFNN）. The experiments on different tool wears of the multivariable features reveal that the results of monitoring and recognition are significant and effective.

Development of Aromatic Image Map and Evaluation of Aromatic Oil Based on Brain Wave

The effect of fragrances on drivers has been examined, in order to optimize driver’s condition during driving. A map that can clearly show the positioning of various fragrances is created as an initial step of this research and development. Sensory evaluation data of 12 kinds of fragrance samples, which are tested on 64 subjects, are used for the creation of this map. The “Aromatic Image Map” can be used to confirm the distribution of the characteristics and the subjects’ preferences for each fragrance. Furthermore, the validity of the “Aromatic Image Map” is inspected experimentally, based on the difference in recovery from stress among the fragrances. Six subjects participate in the experiment, and the four kinds of fragrances that stand at the specific positions on the “Aromatic Image Map” are used. As a result, this enables us to inspect the validity of the position of each fragrance on “Aromatic Image Map”.

Effects of Orbital Motion on the Velocity Field of Boundary Layer Flow over a Rotating Disk

The purpose of this study is to investigate experimentally the effects of orbital motion on the velocity field of boundary layer flow over a rotating disk. The characteristics of velocity field at a fixed orbital angular section measured by a hot-wire anemometer show that the structure of the 3-dimensional boundary layer flow is deformed elliptically and displaced in a certain direction that is not in the orbital radial direction, but the direction of deformation depends on the combination of orbital and rotational directions. For coincide orbital and rotational directions, there are regions where the intensity of low-frequency disturbances increases rapidly in a certain central region (laminar region under pure rotation). The transient vortices, which form streaks on the coating film, are considered to be destroyed by low-frequency disturbances. However, for opposite orbital and rotational directions, the low-frequency disturbances are not observed in any section. As the adding orbital speed increases, the intensity of velocity fluctuations in the turbulence region becomes larger in the expected except in a certain region. This location of the region also depends on the direction of deformation or the combination of orbital and rotational directions.

Transient Response Characteristics of Separated Flow and Heat Transfer in Enlarged Rectangular Channel

Numerical results of three-dimensional separated flow and heat transfer in an enlarged rectangular channel are presented in this paper. The expansion ratio and aspect ratio of the channel are 2.0 and 8.0, respectively. Reynolds number of the flow is 200 and it is over the critical Reynolds number. Over the value, the flow in the symmetric channel becomes to deflect to one side of the walls. Transient response characteristics of the flow and heat transfer in the channel with the fully developed flow imposed one cycle of a pulsating fluctuation at the inlet are investigated. Vortex structure generated in the channel is visualized with a helicity isosurface. In the case of the fluctuation of Strouhal number 0.05, small streamwise vortices appear near the side walls and slightly upstream of the reattachment region of the short separation bubble. The vortices elongate and shed some vortices. These vortices attract some pairs of the streamwise vortices near the reattachment region quickly and they drift downstream along the side walls. They are inclined from the walls and are decaying gradually. It is clarified that high Nusselt number area appears and shifts downstream in accordance with the root of the vortices.

Numerical Investigation of Two-Phase Flow through a T-Junction Microchannel Reactor

Recently, microreactors have become available to be fabricated and used safely. The performance of these microreactors depends on the behavior of the multiphase flow hydrodynamics. Gas-liquid flow through T-junction microchannel reactor is simulated numerically using VOF （volume of fluid） method. 2-D （Two-dimensional） and 3-D （three-dimensional） models of the T-junction microchannel reactor were introduced to the simulations. Both 2-D and 3-D simulations for nitrogen-water flow were performed in the FLUENT （Fluent. Inc.） computational fluid dynamics package. The third direction effect has been studied by comparing the results of the 2-D and 3-D simulations with the published experimental data. Also, the bubble slug length was calculated for the 2-D and 3-D simulations. Furthermore, the hydrodynamics of the flow was studied for the 2-D and 3-D simulations, and compared with other experimental data. The pressure drop, mean bubble velocity, the velocity distribution and the void fraction were calculated and found to be in good agreement with published data.

Effect of Disk Edge Profile on Scattering Characteristics of Liquid Droplets Splashed from Spinning Disk

Effects of disk edge profile on scattering characteristics of liquid droplets splashed from a rotating disk edge are experimentally investigated. In the present research, aluminum disks are utilized and purified water is employed for liquid. Scattering phenomena of the droplets are captured by the high-speed digital camera. Distribution of the droplet diameter is evaluated from these images and distributions of horizontal flying velocity component and angle of the droplets are measured by human visual observation of images. Liquid filaments are stretched outward from the stagnant liquid layer on lateral surface of disk edge by centrifugal force. Two main peaks appear in the distribution of the scattered droplet diameter and they are originated from large terminal droplets and small droplets generated from filamentwise breakup. Most of the scattered droplets fly slightly inside of the tangential direction of the disk edge. The water droplets splashed from the disk scatters with regularity compared with ethanol droplets.

Study of Interaction between Supersonic Flow and Rods or Jets Surrounded by Porous Cavity

In this experiment, the effects of the combination of jets or rods and a porous cavity on the supersonic flow field are studied by means of visualization of schlieren method and the measurements of wall static pressures and the flow direction in the cavity with the thermal tuft probe. Three cases of jets or rods arrangements are tested in the experiments. As a result, a bow shock wave which is generated by the jets or rods is observed by mean of schlieren method. And it is confirmed that the expansion region appears downstream of the rods but is not in case of the jets pattern. Moreover the pressure ratios of starting shock wave passing through porous cavity for jets pattern differ from that of rods pattern. In the cavity, the flow direction at the measurement position in the cavity is always opposite to the main flow, as long as the starting shock wave is located upstream of the porous cavity for all cases. Difference in the backward flow ratio between the jets and rods patterns is observe after the starting shock wave passes through the porous cavity.

Combined Effects of Centrifugal and Coriolis Instability of the Flow through a Rotating Curved Duct with Rectangular Cross Section

Combined effects of centrifugal and coriolis instability of the flow through a rotating curved duct with rectangular cross section have been studied numerically by using a spectral method, and covering a wide range of the Taylor number ?for a constant Dean number. The rotation of the duct about the center of curvature is imposed in the positive direction, and the effects of rotation (Coriolis force) on the flow characteristics are investigated. As a result, multiple branches of asymmetric steady solutions with two-, three-and multi-vortex solutions are obtained. To investigate the non-linear behavior of the unsteady solutions, time evolution calculations as well as power spectrum of the unsteady solutions are performed, and it is found that the unsteady flow undergoes through various flow instabilities in the scenario “chaotic?→ multi-periodic?→ periodic?→ steady-state”, if Tr is increased in the positive direction. The present results show the characteristics of both the secondary flow and axial flow distribution in the flow.

Evaluation of Surface Roughness of Metal and Alloy Material

Turning clearance angle is changed machining characteristics. In this study, the experiments start from choosing two workpiece materials that are machine structural carbon steel, chrome-molyb- denum steel. Then, the experiments show specifically how features of selected materials changed when they were processed with machining operation. In order to find the surface roughness of workpiece materials, the workpiece materials which have higher tensile strength showed much better value of surface roughness in a surface roughness tester. Moreover, process feed rate was compared between 0.05 mm/rev and 0.10 mm/rev. When process feed rate was 0.05 mm/rev, surface roughness has superior results without reference to the quality of the materials.

Behaviors of Crystallization for Osmotic Pressure under Microwave Irradiation

We studied chemical garden in order to investigate precipitation behavior for osmotic pressure under microwave irradiation. The salt concentration and microwave irradiation power were varied. Microwave irradiation induced release of osmotic pressure and change of precipitation pattern because polar molecules vibrate and rotate in an electromagnetic field. For example, the width of precipitation increased and the number of rapture of the membrane decreased due to the release of osmotic pressure by the irradiation. Accordingly, microwave irradiation accelerated the diffusion of ionic molecules through the membrane.

Modelling and Control of Pressurized Molten Metal in Press Casting

This paper presents a modeling and control of molten metal＇s pressure in pressing process using an innovative iron casting developed by our group. In this method, molten metal is directly poured into a lower mold, and then pressed to fill cavity by an upper mold being lowered down. For complex liquid flow during pressing, the liquid＇s pressure changing inside vertical path with various contraction and expansion geometries is newly modeled via the unstationary Bernoulli equation. The mathematical model is derived for a control design of pressing. To conduct the pressing velocity design algorithm, an unknown parameter of proposed model considering viscous flow is identified by using CFD （Computational Fluid Dynamics） with heat flow calculation. Control performance using a multi-switching velocity pattern is confirmed as an effective control design using the pressure model, because the pressure fluctuation has discontinuous variation points. Substituting detailed information for mold shape, poured volume and initial temperature into a developed control input generator, an optimum pressing velocity design and a robust design for defect-free production are proposed by the design algorithm based on the construction of an inverse system comprised of the sequential switching from higher to lower speed. Consequently, the effectiveness of the pressing control with reasonable pressure suppression has been demonstrated through CFD.

Modeling&Evaluating the Performance of Convolutional Neural Networks for Classifying Steel Surface Defects

Recently,outstanding identification rates in image classification tasks were achieved by convolutional neural networks(CNNs).to use such skills,selective CNNs trained on a dataset of well-known images of metal surface defects captured with an RGB camera.Defects must be detected early to take timely corrective action due to production concerns.For image classification up till now,a model-based method has been utilized,which indicated the predicted reflection characteristics of surface defects in comparison to flaw-free surfaces.The problem of detecting steel surface defects has grown in importance as a result of the vast range of steel applications in end-product sectors such as automobiles,households,construction,etc.Themanual processes for detections are time-consuming,labor-intensive,and expensive.Different strategies have been used to automate manual processes,but CNN models have proven to be the most effective rather than image processing andmachine learning techniques.By using differentCNNmodels with fine-tuning,easily compare their performance and select the best-performing model for the same kinds of tasks.However,it is important that using different CNN models either from fine tuning can be computationally expensive and time-consuming.Therefore,our study helps the upcoming researchers to choose the CNN without considering the issues of model complexity,performance,and computational resources.In this article,the performance of various CNN models like Visual Geometry Group,VGG16,VGG19,ResNet152,ResNet152V2,Xception,InceptionV3,InceptionResNetV2,NASNetLarge,MobileNetV2,and DenseNet201 with transfer learning techniques are evaluated.These models were chosen based on their popularity and impact in the field of computer vision research,as well as their performance on benchmark datasets.According to the outcomes,DenseNet201 outperformed the other CNN models and had the greatest detection rate on the NEU dataset,falling in at 98.37 percent.

Experimental Study on Combustion Characteristics of Unused Biomasses in Compact Combustor

The aim of the present study is to develop the biomass furnace combustor which can effectively employ four unused biomasses, i.e., wood bark, wood branch, bamboo, and grass as a fuel. Emphasis is placed on the combustion gas components and combustion gas temperature in the combustor. It is found from the study that： （1） Four unused biomasses can take plate self combustion and the stable combustion yield; （2） Different combustion temperature distribution appears in combustor and is affected by each biomass; （3） The concentrations of nitrogen oxide and sulfur oxides are lower than the discharge standard value; （4） Higher thermal efficiency yields for bark, bamboo and grass.