Search results for: friction push plug welding
534 Off-Shore Wind Turbines: The Issue of Soil Plugging during Pile Installation
Authors: Mauro Iannazzone, Carmine D'Agostino
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Off-shore wind turbines are currently considered as a reliable source of renewable energy Worldwide and especially in the UK. Most of the operational off-shore wind turbines located in shallow waters (i.e. < 30 m) are supported on monopiles. Monopiles are open-ended steel tubes with diameter ranging between 4 to 6 m. It is expected that future off-shore wind farms will be located in water depths as high as 70 m. Therefore, alternative foundation arrangements are needed. Foundations for off-shore structures normally consist of open-ended piles driven into the soil by means of impact hammers. During pile installation, the soil inside the pile may be mobilized by the increasing shear strength such as to prevent more soil from entering the pile. This phenomenon is known as soil plugging, and represents an important issue as it may change significantly the driving resistance of open-ended piles. In fact, if the plugging formation is unexpected, the installation may require more powerful and more expensive hammers. Engineers need to estimate whether the driven pile will be installed in a plugged or unplugged mode. As a consequence, a prediction of the degree of soil plugging is required in order to correctly predict the drivability of the pile. This work presents a brief review of the state-of-the-art of pile driving and approaches used to predict formation of soil plugs. In addition, a novel analytical approach is proposed, which is based on the vertical equilibrium of a plugged pile. Differently from previous studies, this research takes into account the enhancement of the stress within the soil plug. Finally, the work presents and discusses a series of experimental tests, which are carried out on small-scale models piles to validate the analytical solution.Keywords: off-shore wind turbines, pile installation, soil plugging, wind energy
Procedia PDF Downloads 309533 Study of Tribological Behaviour of Al6061/Silicon Carbide/Graphite Hybrid Metal Matrix Composite Using Taguchi's Techniques
Authors: Mohamed Zakaulla, A. R. Anwar Khan
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Al6061 alloy base matrix, reinforced with particles of silicon carbide (10 wt %) and Graphite powder (1wt%), known as hybrid composites have been fabricated by liquid metallurgy route (stir casting technique) and optimized at different parameters like applied load, sliding speed and sliding distance by taguchi method. A plan of experiment generated through taguchi technique was used to perform experiments based on L27 orthogonal array. The developed ANOVA and regression equations are used to find the optimum coefficient of friction and wear under the influence of applied load, sliding speed and sliding distance. On the basis of “smaller the best” the dry sliding wear resistance was analysed and finally confirmation tests were carried out to verify the experimental results.Keywords: analysis of variance, dry sliding wear, hybrid composite, orthogonal array, Taguchi technique
Procedia PDF Downloads 459532 A Case Study: Remediation of Abandoned Mines for Residential Development
Authors: Issa S. Oweis, Gary Gartenberg, Luma J. Oweis
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The site for a residential apartment building overlies an abandoned iron mine in granitic gneiss in northern New Jersey. The mine stope is about 137 m (450 long) and dipping over 344m (800 feet) at 450 to 500. As the building footprint straddles, the mine site needed remediation. The remediation scheme consisted of compaction grouting a minimum 10 m (30 ft.) depth of the mine stope in rock to establish a buttress for the hanging wall and allow support of the building foundation. The rock strength parameters (friction and cohesion) were established based on Hoek Geologic Strength Index (GSI). The derived strength parameters were used in the wedge analysis to simulate rock cave-in. It was concluded that a cave-in would be unlikely. Verification holes confirmed the effectiveness of grouting. Although post grouting micro gravity survey depicted a few anomalies, no anomalies were found to exist by further drilling and excavation.Keywords: grout, stope, rock, properties
Procedia PDF Downloads 324531 The Influence of Substrate and Temperature on the Growth of Phytophthora palmivora of Cocoa Black Pod Disease
Authors: Suhaida Salleh, Tee Yei Kheng
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Black pod is the most commonly destructive disease of cacao (Theobroma cacao) which cause major losses to global production of cocoa beans. The genus of Phytophthora is the important pathogen of this disease worldwide. The species of P. megakarya causes black pod disease in West Africa, whereas P. capsici and P. citrophthora cause the incident in Central and South America. In Malaysia, this disease is caused by P. palmivora which infect all stages of pod development including flower cushion, cherelle, immature and mature pods. This pathogen destroys up to 10% of trees yearly through stem cankers and causes 20 to 30% pod damages through black pod rot. Since P. palmivora has a high impact on cocoa yield, it is crucial to identify some of the abiotic factors that can constrain their growth. In an effort to evaluate the effect of different substrates and temperatures to the growth of P. palmivora, a laboratory study was done under a different range of temperatures. Different substrate for the growth of P. palmivora were used which are corn meal agar (CMA) media and detached pod of cocoa. An agar plug of seven days old of P. palmivora growth was transferred on both substrates and incubated at 24, 27, 30, 33 and 36ᵒC, respectively. The diameter of lesion on pod and the cultural growth of pathogen was recorded for 7 consecutive days. The optimum incubation temperature of P. palmivora on both substrates is at 27ᵒC. However, the growth tends to be inhibited as the temperature increases. No lesion developed on pod surface incubated at 36ᵒC and only a small lesion observed at 33ᵒC. The sporulation with the formation of white mycelial growth on pod surface was only visible at optimum temperature, 27ᵒC. On CMA, the pathogen grew over the entire range of temperatures tested. The study is, therefore, concluded that P. palmivora grow the best at temperature of 27ᵒC on both substrates and their growth begin to inhibit when the temperature rises to more than 27ᵒC. The growth pattern of this pathogen is similar on both pod surface and cultural media.Keywords: cocoa, Phytophthora palmivora, substrate, temperature
Procedia PDF Downloads 186530 An Automated Optimal Robotic Assembly Sequence Planning Using Artificial Bee Colony Algorithm
Authors: Balamurali Gunji, B. B. V. L. Deepak, B. B. Biswal, Amrutha Rout, Golak Bihari Mohanta
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Robots play an important role in the operations like pick and place, assembly, spot welding and much more in manufacturing industries. Out of those, assembly is a very important process in manufacturing, where 20% of manufacturing cost is wholly occupied by the assembly process. To do the assembly task effectively, Assembly Sequences Planning (ASP) is required. ASP is one of the multi-objective non-deterministic optimization problems, achieving the optimal assembly sequence involves huge search space and highly complex in nature. Many researchers have followed different algorithms to solve ASP problem, which they have several limitations like the local optimal solution, huge search space, and execution time is more, complexity in applying the algorithm, etc. By keeping the above limitations in mind, in this paper, a new automated optimal robotic assembly sequence planning using Artificial Bee Colony (ABC) Algorithm is proposed. In this algorithm, automatic extraction of assembly predicates is done using Computer Aided Design (CAD) interface instead of extracting the assembly predicates manually. Due to this, the time of extraction of assembly predicates to obtain the feasible assembly sequence is reduced. The fitness evaluation of the obtained feasible sequence is carried out using ABC algorithm to generate the optimal assembly sequence. The proposed methodology is applied to different industrial products and compared the results with past literature.Keywords: assembly sequence planning, CAD, artificial Bee colony algorithm, assembly predicates
Procedia PDF Downloads 233529 Effect of Clay Content on the Drained Shear Strength
Authors: Navid Khayat
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Drained shear strength of saturated soils is fully understood. Shear strength of unsaturated soils is usually expressed in terms of soil suction. Evaluation of shear strength of compacted mixtures of sand–clay at optimum water content is main purpose of this research. To prepare the required samples, first clay and sand are mixed in 10, 30, 50, and 70 percent by dry weight and then compacted at the proper optimum water content according to the standard proctor test. The samples were sheared in direct shear machine. Stress –strain relationship of samples indicated a ductile behavior. Most of the samples showed a dilatancy behavior during the shear and the tendency for dilatancy increased with the increase in sand proportion. The results show that with the increase in percentage of sand a decrease in cohesion intercept c' for mixtures and an increase in the angle of internal friction Φ’is observed.Keywords: clay, sand, drained shear strength, cohesion intercept
Procedia PDF Downloads 429528 Effects of Cattaneo-Christov Heat Flux on 3D Magnetohydrodynamic Viscoelastic Fluid Flow with Variable Thermal Conductivity
Authors: Muhammad Ramzan
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A mathematical model has been envisaged to discuss three-dimensional Viscoelastic fluid flow with an effect of Cattaneo-Christov heat flux in attendance of magnetohydrodynamic (MHD). Variable thermal conductivity with the impact of homogeneous-heterogeneous reactions and convective boundary condition is also taken into account. Homotopy analysis method is engaged to obtain series solutions. Graphical illustrations depicting behaviour of sundry parameters on skin friction coefficient and all involved distributions are also given. It is observed that velocity components are decreasing functions of Viscoelastic fluid parameter. Furthermore, strength of homogeneous and heterogeneous reactions have opposite effects on concentration distribution. A comparison with a published paper has also been established and an excellent agreement is obtained; hence reliable results are being presented.Keywords: Cattaneo Christov heat flux, homogenous-heterogeneous reactions, magnetic field, variable thermal conductivity
Procedia PDF Downloads 193527 Soil Parameters Identification around PMT Test by Inverse Analysis
Authors: I. Toumi, Y. Abed, A. Bouafia
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This paper presents a methodology for identifying the cohesive soil parameters that takes into account different constitutive equations. The procedure, applied to identify the parameters of generalized Prager model associated to the Drucker & Prager failure criterion from a pressuremeter expansion curve, is based on an inverse analysis approach, which consists of minimizing the function representing the difference between the experimental curve and the simulated curve using a simplex algorithm. The model response on pressuremeter path and its identification from experimental data lead to the determination of the friction angle, the cohesion and the Young modulus. Some parameters effects on the simulated curves and stresses path around pressuremeter probe are presented. Comparisons between the parameters determined with the proposed method and those obtained by other means are also presented.Keywords: cohesive soils, cavity expansion, pressuremeter test, finite element method, optimization procedure, simplex algorithm
Procedia PDF Downloads 288526 Outstanding Lubricant Using Fluorographene as an Extreme Pressure Additive
Authors: Adriana Hernandez-Martinez, Edgar D. Ramon-Raygoza
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Currently, there has been a great interest, during the last years, on graphene due to its lubricant properties on friction and antiwear processes. Likewise, fluorographene has also been gaining renown due to its excellent chemical and physical properties which have been mostly applied in the electronics industry. Nevertheless, its tribological properties haven’t been analyzed thoroughly. In this paper, fluorographene was examined as an extreme pressure additive and the nano lubricant made with a cutting fluid and fluorographene in the range of 0.01-0.5% wt, which proved to withstand 53.78% more pounds than the conventional product and 7.12% more than the nano lubricant with graphene in a range between 0.01-0.5% wt. Said extreme pressure test was carried out with a Pin and Vee Block Tribometer following an ASTM D3233A test. The fluorographene used has a low C/F ratio, which reflects a greater presence of atomic fluorine and its low oxygen percentage, supports the substitution of oxygen-containing groups by fluorine. XPS Spectra shows high atomic fluorine content of 56.12%, and SEM analysis details the formation of long and clear crystalline structures, in the fluorographene used.Keywords: extreme pressure additive, fluorographene, nanofluids, nanolubricant
Procedia PDF Downloads 116525 Enhancement of Mechanical and Dissolution Properties of a Cast Magnesium Alloy via Equal Angular Channel Processing
Authors: Tim Dunne, Jiaxiang Ren, Lei Zhao, Peng Cheng, Yi Song, Yu Liu, Wenhan Yue, Xiongwen Yang
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Two decades of the Shale Revolution has transforming transformed the global energy market, in part by the adaption of multi-stage dissolvable frac plugs. Magnesium has been favored for the bulk of plugs, requiring development of materials to suit specific field requirements. Herein, the mechanical and dissolution results from equal channel angular pressing (ECAP) of two cast dissolvable magnesium alloy are described. ECAP was selected as a route to increase the mechanical properties of two formulations of dissolvable magnesium, as solutionizing failed. In this study, 1” square cross section samples cast Mg alloys formulations containing rare earth were processed at temperatures ranging from 200 to 350 °C, at a rate of 0.005”/s, with a backpressure from 0 to 70 MPa, in a brass, or brass + graphite sheet. Generally, the yield and ultimate tensile strength (UTS) doubled for all. For formulation DM-2, the yield increased from 100 MPa to 250 MPa; UTS from 175 MPa to 325 MPa, but the strain fell from 2 to 1%. Formulation DM-3 yield increased from 75 MPa to 200 MPa, UTS from 150 MPa to 275 MPa, with strain increasing from 1 to 3%. Meanwhile, ECAP has also been found to reduce the dissolution rate significantly. A microstructural analysis showed grain refinement of the alloy and the movement of secondary phases away from the grain boundary. It is believed that reconfiguration of the grain boundary phases increased the mechanical properties and decreased the dissolution rate. ECAP processing of dissolvable high rare earth content magnesium is possible despite the brittleness of the material. ECAP is a possible processing route to increase mechanical properties for dissolvable aluminum alloys that do not extrude.Keywords: equal channel angular processing, dissolvable magnesium, frac plug, mechanical properties
Procedia PDF Downloads 112524 Numerical Simulation of Effect of Various Rib Configurations on Enhancing Heat Transfer of Matrix Cooling Channel
Authors: Seok Min Choi, Minho Bang, Seuong Yun Kim, Hyungmin Lee, Won-Gu Joo, Hyung Hee Cho
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The matrix cooling channel was used for gas turbine blade cooling passage. The matrix cooling structure is useful for the structure stability however the cooling performance of internal cooling channel was not enough for cooling. Therefore, we designed the rib configurations in the matrix cooling channel to enhance the cooling performance. The numerical simulation was conducted to analyze cooling performance of rib configured matrix cooling channel. Three different rib configurations were used which are vertical rib, angled rib and c-type rib. Three configurations were adopted in two positions of matrix cooling channel which is one fourth and three fourth of channel. The result shows that downstream rib has much higher cooling performance than upstream rib. Furthermore, the angled rib in the channel has much higher cooling performance than vertical rib. This is because; the angled rib improves the swirl effect of matrix cooling channel more effectively. The friction factor was increased with the installation of rib. However, the thermal performance was increased with the installation of rib in the matrix cooling channel.Keywords: matrix cooling, rib, heat transfer, gas turbine
Procedia PDF Downloads 451523 Evaluation of Drained Shear Strength of Bentonite-Sand Mixtures
Authors: Navid Khayat
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Drained shear strength of saturated soils is fully understood. Shear strength of unsaturated soils is usually expressed in terms of soil suction. Evaluation of shear strength of compacted mixtures of sand-bentonite at optimum water content is main purpose of this research. To prepare the required samples, first, bentonite and sand are mixed in 10, 30, 50 and 70 percent by dry weight and then compacted at the proper optimum water content according to the standard proctor test. The samples were sheared in direct shear machine. Stress-strain relationship of samples indicated a ductile behavior. Most of the samples showed a dilatancy behavior during the shear and the tendency for dilatancy increased with the increase in sand proportion. The results show that with the increase in percentage of sand a decrease in cohesion intercept c' for mixtures and an increase in the angle of internal friction Φ’is observed.Keywords: bentonite, sand, drained shear strength, cohesion intercept
Procedia PDF Downloads 313522 Estimation of the External Force for a Co-Manipulation Task Using the Drive Chain Robot
Authors: Sylvain Devie, Pierre-Philippe Robet, Yannick Aoustin, Maxime Gautier
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The aim of this paper is to show that the observation of the external effort and the sensor-less control of a system is limited by the mechanical system. First, the model of a one-joint robot with a prismatic joint is presented. Based on this model, two different procedures were performed in order to identify the mechanical parameters of the system and observe the external effort applied on it. Experiments have proven that the accuracy of the force observer, based on the DC motor current, is limited by the mechanics of the robot. The sensor-less control will be limited by the accuracy in estimation of the mechanical parameters and by the maximum static friction force, that is the minimum force which can be observed in this case. The consequence of this limitation is that industrial robots without specific design are not well adapted to perform sensor-less precision tasks. Finally, an efficient control law is presented for high effort applications.Keywords: control, identification, robot, co-manipulation, sensor-less
Procedia PDF Downloads 153521 Dynamic Model of Automatic Loom on SimulationX
Authors: A. Jomartov, A. Tuleshov, B. Tultaev
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One of the main tasks in the development of textile machinery is to increase the rapidity of automatic looms, and consequently, their productivity. With increasing automatic loom speeds, the dynamic loads on their separate mechanisms and moving joints sharply increase. Dynamic research allows us to determine the weakest mechanisms of the automatic loom. The modern automatic loom consists of a large number of structurally different mechanisms. These are cam, lever, gear, friction and combined cyclic mechanisms. The modern automatic loom contains various mechatronic devices: A device for the automatic removal of faulty weft, electromechanical drive warp yarns, electronic controllers, servos, etc. In the paper, we consider the multibody dynamic model of the automatic loom on the software complex SimulationX. SimulationX is multidisciplinary software for modeling complex physical and technical facilities and systems. The multibody dynamic model of the automatic loom allows consideration of: The transition processes, backlash at the joints and nodes, the force of resistance and electric motor performance.Keywords: automatic loom, dynamics, model, multibody, SimulationX
Procedia PDF Downloads 338520 Analysis of Brushless DC Motor with Trapezoidal Back EMF Using Matlab
Authors: Taha Ahmed Husain
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The dynamic characteristics such as speed and torque as well as voltages and currents of pwm brushless DC motor inverter are analyzed with a MATLAB model. The contribution of external load torque and friction torque is monitored. The switching function technique is adopted for the current control of the embedded three phase inverter that drives the brushless DC motor.In switching functions the power conversions circuits can be modeled according to their functions rather than circuit topologies. Therefore, it can achieve simplification of the overall power conversion functions. The trapezoidal type (back emf) is used in the model as ithas lower switching loss compared with sinusoidal type (back emf). Results show reliable time analysis for speed, torque, phase and line voltages and currents and the effect of current commutation is clearly observed.Keywords: BLDC motor, brushless dc motors, pwm inverter, DC motor control, trapezoidal back emf, ripple torque in brushless DC motor
Procedia PDF Downloads 588519 Structural Performance Evaluation of Electronic Road Sign Panels Reflecting Damage Scenarios
Authors: Junwon Seo, Bipin Adhikari, Euiseok Jeong
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This paper is intended to evaluate the structural performance of welded electronic road signs under various damage scenarios (DSs) using a finite element (FE) model calibrated with full-scale ultimate load testing results. The tested electronic road sign specimen was built with a back skin made of 5052 aluminum and two channels and a frame made of 6061 aluminum, where the back skin was connected to the frame by welding. The size of the tested specimen was 1.52 m long, 1.43 m wide, and 0.28 m deep. An actuator applied vertical loads at the center of the back skin of the specimen, resulting in a displacement of 158.7 mm and an ultimate load of 153.46 kN. Using these testing data, generation and calibration of a FE model of the tested specimen were executed in ABAQUS, indicating that the difference in the ultimate load between the calibrated model simulation and full-scale testing was only 3.32%. Then, six different DSs were simulated where the areas of the welded connection in the calibrated model were diminished for the DSs. It was found that the corners at the back skin-frame joint were prone to connection failure for all the DSs, and failure of the back skin-frame connection occurred remarkably from the distant edges.Keywords: computational analysis, damage scenarios, electronic road signs, finite element, welded connections
Procedia PDF Downloads 87518 The Political Haunting of “Martyrdom” in the Palestinian Context
Authors: Mai Awad
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This paper aims to focus on the phenomenon of martyrdom—particularly its performative aspect—and how social and popular cultural representations address the multiple meanings of the loaded image of a Palestinian martyr. This focus will help us to explore the possible reasons that might push Palestinians to consider pursuing “martyrdom” or suicide operations. Tracing what happened in the past and what is currently happening (that is, haunting) will aid in theorizing how the act/practice of “martyrdom” is produced. It is believed that there are social and political forces, particularly in a colonial society like Palestine, that influence the subject and its experience. But what is unique about this paper is its attempt to disclose the invisible, hidden narratives and complexities of Palestinian life that we do not see. By giving “martyrs” a chance to speak and express their own narratives—since “martyrs” usually leave written letters for their families, which are published after their death—this study must broaden the whole picture and discuss what is missing. The analytic method to be used: For the methodology, the paper recruits discourse analysis as a method for tracing the emergence, circulation, and productivity of the martyrdom discourse across a range of social practices in Palestinians’ everyday life after the Nakba. The paper analyzes the letters that “martyrs” left to their families, relatives, and the Palestinian community after their death. By letting “martyrs” speak for themselves and hearing their unique discourses, the research would suggest that more explanation is needed to describe the “martyr” identity. Hence, it is not possible to study the “martyr” identity in Palestine without understanding the colonial context that governs it and shapes their subjective experience.Keywords: martyrdom, palestine, haunting, nakba 1948
Procedia PDF Downloads 61517 Performance Assessment of Carbon Nano Tube Based Cutting Fluid in Machining Process
Authors: Alluru Gopala Krishna, Thella Babu Rao
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In machining, there is always a problem with heat generation and friction produced during the process as they consequently affect tool wear and surface finish. An instant heat transfer mechanism could protect the cutting tool edge and enhance the tool life by cooling the cutting edge of the tool. In the present work, carbon nanotube (CNT) based nano-cutting fluid is proposed for machining a hard-to-cut material. Tool wear and surface roughness are considered for the evaluation of the nano-cutting fluid in turning process. The performance of nanocoolant is assessed against the conventional coolant and dry machining conditions and it is observed that the proposed nanocoolant has produced better performance than the conventional coolant.Keywords: CNT based nano cutting fluid, tool wear, turning, surface roughness
Procedia PDF Downloads 258516 Seizure Effects of FP Bearings on the Seismic Reliability of Base-Isolated Systems
Authors: Paolo Castaldo, Bruno Palazzo, Laura Lodato
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This study deals with the seizure effects of friction pendulum (FP) bearings on the seismic reliability of a 3D base-isolated nonlinear structural system, designed according to Italian seismic code (NTC08). The isolated system consists in a 3D reinforced concrete superstructure, a r.c. substructure and the FP devices, described by employing a velocity dependent model. The seismic input uncertainty is considered as a random variable relevant to the problem, by employing a set of natural seismic records selected in compliance with L’Aquila (Italy) seismic hazard as provided from NTC08. Several non-linear dynamic analyses considering the three components of each ground motion have been performed with the aim to evaluate the seismic reliability of the superstructure, substructure, and isolation level, also taking into account the seizure event of the isolation devices. Finally, a design solution aimed at increasing the seismic robustness of the base-isolated systems with FPS is analyzed.Keywords: FP devices, seismic reliability, seismic robustness, seizure
Procedia PDF Downloads 408515 The Curvature of Bending Analysis and Motion of Soft Robotic Fingers by Full 3D Printing with MC-Cells Technique for Hand Rehabilitation
Authors: Chaiyawat Musikapan, Ratchatin Chancharoen, Saknan Bongsebandhu-Phubhakdi
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For many recent years, soft robotic fingers were used for supporting the patients who had survived the neurological diseases that resulted in muscular disorders and neural network damages, such as stroke and Parkinson’s disease, and inflammatory symptoms such as De Quervain and trigger finger. Generally, the major hand function is significant to manipulate objects in activities of daily living (ADL). In this work, we proposed the model of soft actuator that manufactured by full 3D printing without the molding process and one material for use. Furthermore, we designed the model with a technique of multi cavitation cells (MC-Cells). Then, we demonstrated the curvature bending, fluidic pressure and force that generated to the model for assistive finger flexor and hand grasping. Also, the soft actuators were characterized in mathematics solving by the length of chord and arc length. In addition, we used an adaptive push-button switch machine to measure the force in our experiment. Consequently, we evaluated biomechanics efficiency by the range of motion (ROM) that affected to metacarpophalangeal joint (MCP), proximal interphalangeal joint (PIP) and distal interphalangeal joint (DIP). Finally, the model achieved to exhibit the corresponding fluidic pressure with force and ROM to assist the finger flexor and hand grasping.Keywords: biomechanics efficiency, curvature bending, hand functional assistance, multi cavitation cells (MC-Cells), range of motion (ROM)
Procedia PDF Downloads 252514 Influence of Thermal Radiation on MHD Micropolar Fluid Flow, Heat and Mass Transfer over Vertical Flat Plate
Authors: Alouaoui Redha, Ferhat Samira, Bouaziz Mohamed Najib
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In this work, we examine the thermal radiation effect on heat and mass transfer in steady laminar boundary layer flow of an incompressible viscous micropolar fluid over a vertical plate, with the presence of a magnetic field. Rosseland approximation is applied to describe the radiative heat flux in the energy equation. The resulting similarity equations are solved numerically. Many results are obtained and representative set is displayed graphically to illustrate the influence of the various parameters on different profiles. The conclusion is drawn that the flow field, temperature, concentration and microrotation as well as the skin friction coefficient and the both local Nusselt and local Sherwood numbers are significantly influenced by Magnetic parameter, material parameter and thermal radiation parameter.Keywords: MHD, micropolar fluid, thermal radiation, heat and mass transfer, boundary layer
Procedia PDF Downloads 445513 Wireworms under the Sword of Damocles: Attraction to Maize Root Volatiles
Authors: Diana La Forgia, Jean Baptiste Thibord, François Verheggen
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Volatiles Organic Compound (VOCs) are one of the many features of defense used by plants in their eternal fight against pests. Their main role is to attract the natural enemies of the herbivores. But on another hand, they can be used by the same herbivores to locate plants while foraging. In an attempt to fill a gap of knowledge in a complex web of interactions, we focused on wireworms (Coleoptera:Elateridae). Wireworms whose larvae feed on roots are one of the most spread pests of valuable crops such as maize and potatoes, causing important economical damage. Little is known about the root compounds that are playing a role in the attraction of the larvae. In order to know more about these compounds, we compared four different maize varieties (Zea mays mays) that are known to have different levels of attraction, from weak to strong, for wireworms in fields. We tested the attraction of larvae in laboratory conditions in dual-choice olfactometer assays where they were offered all possible combinations of the four maize varieties. Contemporary, we collected the VOCs of each variety during 24h using a push-and-pull system. The collected samples were then analyzed by gas chromatography coupled with a mass spectrometer (GC-MS) to identify their molecular profiles. The choice of the larvae was dependent on the offered combination and some varieties were preferred to others. Differences were also observed in terms of quantitative and qualitative emissions of volatile profiles between the maize varieties. Our aim is to develop traps based on VOCs from maize roots to open a new frontier in wireworms management.Keywords: integrated pest management, maize roots, plant defense, volatile organic compounds, wireworms
Procedia PDF Downloads 150512 Trafficking of Women in International Migration: Issues and Major Challenges in Present Scenario
Authors: Neha Singh, Anshuman Rana
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Gender-Based Violence (GBV) is a violation of human rights and a form of discrimination which reinforces inequalities between men and women. It is defined as violence that is directed against a person on the basis of gender. There has been increased attention to human trafficking that has exposed to illegal migration. Trafficking is complex, but it generally takes place due to “push and pull factors”. India is both a source as well as a transit country for trafficking. Women are bought and sold with impunity and trafficked to other countries. They are forced to work as sex worker, forced labour and other practices of slavery. Trafficked victims often suffer from serious abuse and physical exhaustion. The effects of violence on women vary widely. GBV typically has physical, psychological and social effects. They face unwanted pregnancies, miscarriages, high rate of infertility and sexually transmitted disease. The social exclusion of women is so great that it constitutes a new form of apartheid. Women are considered as lesser value and deprived of their fundamental rights. Violation of human rights and fundamental freedom such as- trafficking of women, girls for sex trade, forced prostitution and sex tourism have become the focus of internationally organized crimes. My paper will analyse the impact of violence on society as well. Law alone cannot change the scenario and problem of gender-biasness. The whole issue of gender violence needs social awakening and change in attitude of masses, so that due respect and equal status is given to women.Keywords: gender-based violence, trafficking, migration, violence impact, social exclusion, law enforcement
Procedia PDF Downloads 279511 Unsteady Forced Convection Flow and Heat Transfer Past a Blunt Headed Semi-Circular Cylinder at Low Reynolds Numbers
Authors: Y. El Khchine, M. Sriti
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In the present work, the forced convection heat transfer and fluid flow past an unconfined semi-circular cylinder is investigated. The two-dimensional simulation is employed for Reynolds numbers ranging from 10 ≤ Re ≤ 200, employing air (Pr = 0.71) as an operating fluid with Newtonian constant physics property. Continuity, momentum, and energy equations with appropriate boundary conditions are solved using the Computational Fluid Dynamics (CFD) solver Ansys Fluent. Various parameters flow such as lift, drag, pressure, skin friction coefficients, Nusselt number, Strouhal number, and vortex strength are calculated. The transition from steady to time-periodic flow occurs between Re=60 and 80. The effect of the Reynolds number on heat transfer is discussed. Finally, a developed correlation of Nusselt and Strouhal numbers is presented.Keywords: forced convection, semi-circular cylinder, Nusselt number, Prandtl number
Procedia PDF Downloads 101510 The Comparative Study of the Characteristics of Chinese and Foreign Excellent Woman’s Single Players’ Serve, Receive Tactic Author
Authors: Zhai Yuan, Wu Xueqing
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This article statistics the technology which used by Chinese and foreign excellent players in the game, including types and serves areas,receive technology and effect and utilization ratio receiving and losing points. The sample is che videos which is world's top matches of excellent badminton athletes of che single, including Chinese players’ 43 games and foreign players’ 38 games. Conclusion: For the serving, Chinese and foreign single players are to give priority to forehand short-low serve and the long-high serve. And Chinese and foreign players in using forehand short-low serve and drive server exist significant differences; For the serves areas, Chinese and foreign players serve area is concentrated in area 1,5,6. Area 6 has the highest rate of all the district areas, following by the area 1and area 5. Among the 2ed serve area Sino-foreign player, there exist significant differences; In the receiver, when returning the frontcourt shutter, players is given priority to net lift and push. When returning the backcourt shutter, receiver's the best ball is smash, followed by clear and drop shot. Foreign players have higher utilization rate in smash than Chinese players in the backcourt; In the receiver result, Chinese players give priority to actively and equally situation than foreign players, but in negatively receiving is just opposite.Keywords: badminton, woman’s singles, technique and tactics, comparative analysis
Procedia PDF Downloads 535509 Knowledge Transformation Flow (KTF) of Visually Impaired Students: The Virtual Knowledge System as a New Service Innovation
Authors: Chatcai Tangsri, Onjaree Na-Takuatoong
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This paper aims to present the key factors that support the decision to use the technology and to present the knowledge transformation flow of visually impaired students after the use of virtual knowledge system as proposed as a new service innovation to universities in Thailand. Correspondents of 27 visually impaired students are involved in this research. Total of 25 students are selected from the University that mainly conducts non-classroom teaching environment; while another 2 visually impaired students are selected from classroom teaching environment. All of them are fully involved in the study along 8 weeks duration. All correspondents are classified into 5 small groups in various conditions. The research results revealed that the involvement from knowledge facilitator can push out for the behavioral actual use of the virtual knowledge system although there is no any developed intention to use behaviors. Secondly, the situations that the visually impaired students inadequate of the knowledge sources that usually provided by assistants i.e. peers, audio files etc. In this case, they will use the virtual knowledge system for both knowledge access and knowledge transfer request. With this evidence, the need of knowledge would play a stronger role than all technology acceptance factors. Finally, this paper revealed that the knowledge transfer in the normal method that students have a chance to physically meet up is still confirmed as their preference method. In term of other aspects of technology acceptance, it will be discussed together with challenges and recommendations at the end of this paper.Keywords: knowledge system, visually impaired students, higher education, knowledge management enable technology, synchronous/asynchronous knowledge access, synchronous/asynchronous knowledge transfer
Procedia PDF Downloads 353508 Material Characterization and Numerical Simulation of a Rubber Bumper
Authors: Tamás Mankovits, Dávid Huri, Imre Kállai, Imre Kocsis, Tamás Szabó
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Non-linear FEM calculations are indispensable when important technical information like operating performance of a rubber component is desired. Rubber bumpers built into air-spring structures may undergo large deformations under load, which in itself shows non-linear behavior. The changing contact range between the parts and the incompressibility of the rubber increases this non-linear behavior further. The material characterization of an elastomeric component is also a demanding engineering task. In this paper, a comprehensive investigation is introduced including laboratory measurements, mesh density analysis and complex finite element simulations to obtain the load-displacement curve of the chosen rubber bumper. Contact and friction effects are also taken into consideration. The aim of this research is to elaborate an FEM model which is accurate and competitive for a future shape optimization task.Keywords: rubber bumper, finite element analysis, compression test, Mooney-Rivlin material model
Procedia PDF Downloads 501507 Performance Evaluation and Plugging Characteristics of Controllable Self-Aggregating Colloidal Particle Profile Control Agent
Authors: Zhiguo Yang, Xiangan Yue, Minglu Shao, Yue Yang, Rongjie Yan
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It is difficult to realize deep profile control because of the small pore-throats and easy water channeling in low-permeability heterogeneous reservoir, and the traditional polymer microspheres have the contradiction between injection and plugging. In order to solve this contradiction, the controllable self-aggregating colloidal particles (CSA) containing amide groups on the surface of microspheres was prepared based on emulsion polymerization of styrene and acrylamide. The dispersed solution of CSA colloidal particles, whose particle size is much smaller than the diameter of pore-throats, was injected into the reservoir. When the microspheres migrated to the deep part of reservoir, , these CSA colloidal particles could automatically self-aggregate into large particle clusters under the action of the shielding agent and the control agent, so as to realize the plugging of the water channels. In this paper, the morphology, temperature resistance and self-aggregation properties of CSA microspheres were studied by transmission electron microscopy (TEM) and bottle test. The results showed that CSA microspheres exhibited heterogeneous core-shell structure, good dispersion, and outstanding thermal stability. The microspheres remain regular and uniform spheres at 100℃ after aging for 35 days. With the increase of the concentration of the cations, the self-aggregation time of CSA was gradually shortened, and the influence of bivalent cations was greater than that of monovalent cations. Core flooding experiments showed that CSA polymer microspheres have good injection properties, CSA particle clusters can effective plug the water channels and migrate to the deep part of the reservoir for profile control.Keywords: heterogeneous reservoir, deep profile control, emulsion polymerization, colloidal particles, plugging characteristic
Procedia PDF Downloads 230506 An Improved Heat Transfer Prediction Model for Film Condensation inside a Tube with Interphacial Shear Effect
Authors: V. G. Rifert, V. V. Gorin, V. V. Sereda, V. V. Treputnev
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The analysis of heat transfer design methods in condensing inside plain tubes under existing influence of shear stress is presented in this paper. The existing discrepancy in more than 30-50% between rating heat transfer coefficients and experimental data has been noted. The analysis of existing theoretical and semi-empirical methods of heat transfer prediction is given. The influence of a precise definition concerning boundaries of phase flow (it is especially important in condensing inside horizontal tubes), shear stress (friction coefficient) and heat flux on design of heat transfer is shown. The substantiation of boundary conditions of the values of parameters, influencing accuracy of rated relationships, is given. More correct relationships for heat transfer prediction, which showed good convergence with experiments made by different authors, are substantiated in this work.Keywords: film condensation, heat transfer, plain tube, shear stress
Procedia PDF Downloads 239505 Landfill Design for Reclamation of Şırnak Coal Mine Dumps: Shalefill Stability and Risk Assessment
Authors: Yıldırım I. Tosun, Halim Cevizci, Hakan Ceylan
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By GEO5 FEM program with four rockfill slope modeling and stability analysis was performed for S1, S2, S3 and S4 slopes where landslides of the shalefills were limited. Effective angle of internal friction (φ'°) 17°-22.5°, the effective cohesion (c') from 0.5 to 1.8 kPa, saturated unit weight 1.78-2.43 g/cm3, natural unit weight 1.9-2.35 g/cm3, dry unit weight 1.97-2.40 g/cm3, the permeability coefficient of 1x10-4 - 6.5x10-4 cm/s. In cross-sections of the slope, GEO 5 FEM program possible critical surface tension was examined. Rockfill dump design was made to prevent sliding slopes. Bulk material designated geotechnical properties using also GEO5 programs FEM and stability program via a safety factor determined and calculated according to the values S3 and S4 No. slopes are stable S1 and S2 No. slopes were close to stable state that has been found to be risk. GEO5 programs with limestone rock fill dump through FEM program was found to exhibit stability.Keywords: slope stability, stability analysis, rockfills, sock stability
Procedia PDF Downloads 478