Search results for: mechanical force
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 1977

Search results for: mechanical force

1167 Seismic Evaluation with Shear Walls and Braces for Buildings

Authors: S. K. Madan, R. S. Malik, V. K. Sehgal

Abstract:

R.C.C. buildings with dual structural system consisting of shear walls (or braces) and moment resisting frames have been widely used to resist lateral forces during earthquakes. The dual systems are designed to resist the total design lateral force in proportion to their lateral stiffness. The response of combination of braces and shear walls has not yet been studied. The combination may prove to be more effective to resist lateral forces during earthquakes. This concept has been applied to regular R.C.C. buildings provided with shear walls, braces and their combinations.

Keywords: Dynamic analysis, Displacement, Dual structural system, Storey drift.

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1166 Bubble Growth in a Two Phase Upward Flow in a Miniature Tube

Authors: R. S. Hassani, S. Chikh, L. Tadrist, S. Radev

Abstract:

A bubbly flow in a vertical miniature tube is analyzed theoretically. The liquid and gas phase are co-current flowing upward. The gas phase is injected via a nozzle whose inner diameter is 0.11mm and it is placed on the axis of the tube. A force balance is applied on the bubble at its detachment. The set of governing equations are solved by use of Mathematica software. The bubble diameter and the bubble generation frequency are determined for various inlet phase velocities represented by the inlet mass quality. The results show different behavior of bubble growth and detachment depending on the tube size.

Keywords: Two phase flow, bubble growth, minichannel, generation frequency.

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1165 Bowden Cable Based Powered Ball and Socket Wrist Actuator

Authors: Samee Ahmad, Adnan Masood, Umar S. Khan

Abstract:

A 2-Degrees of freedom powered prosthetic wrist actuator has been proposed that can provide the Abduction/Adduction & Flexion/Extension movements of the human wrist. The basic structure of the actuator is a Ball and Socket joint and the force is transmitted from the DC geared servo motors to the joint through the Bowden cables. The proposed design is capable of providing the required DOF in both axes i.e. 85° & 90° in flexion extension axis. The size and weight of the actuator lies within the ranges of an average human being-s wrist.

Keywords: Actuator, Ball & Socket, Bowden Cable, Prosthetic, Wrist

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1164 Formation and Evaluation of Lahar/HDPE Hybrid Composite as a Structural Material for Household Biogas Digester

Authors: Lady Marianne E. Polinga, Candy C. Mercado, Camilo A. Polinga

Abstract:

This study was an investigation on the suitability of Lahar/HDPE composite as a primary material for low-cost smallscale biogas digesters. While sources of raw materials for biogas are abundant in the Philippines, cost of the technology has made the widespread utilization of this resource an indefinite proposition. Aside from capital economics, another problem arises with space requirements of current digester designs. These problems may be simultaneously addressed by fabricating digesters on a smaller, household scale to reach a wider market, and to use materials that may accommodate optimization of overall design and fabrication cost without sacrificing operational efficiency. This study involved actual fabrication of the Lahar/HDPE composite at varying composition and geometry, subsequent mechanical and thermal characterization, and implementation of Statistical Analysis to find intrinsic relationships between variables. From the results, Lahar/HDPE composite was found to be feasible for use as digester material from both mechanical and economic standpoints. 

Keywords: Biogas digester, Composite, High density polyethylene, Lahar.

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1163 Exploring the Factors of Inter-Organizational Knowledge Sharing

Authors: Ying-Hueih Chen, Jyh-Jeng Wu, Shu-Hua Chien, Yui-Chuin Shiah

Abstract:

Interorganizational knowledge sharing is the major driving force to maximize the operational benefits across supply chain. Trust is considered as the key to facilitate knowledge sharing. This research proposes shared values and relational embeddedness as antecedents of interorganizational trust. Survey based on managers in major industrial parks in Taiwan confirm that trust is enforced when organizations develop shared values and formed social relational embeddedness. Trust leads to interorganizational knowledge sharing. This research has theoretical and practical implications.

Keywords: Shared Goal, Relational Embeddedness, Trust, Knowledge Sharing.

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1162 3D Numerical Simulation on Annular Diffuser Temperature Distribution Enhancement by Different Twist Arrangement

Authors: Ehan Sabah Shukri, Wirachman Wisnoe

Abstract:

The influence of twist arrangement on the temperature distribution in an annular diffuser fitted with twisted rectangular hub is investigated. Different pitches (Y = 120 mm, 100 mm, 80 mm, and 60 mm) for the twist arrangements are simulated to be compared. The geometry of the annular diffuser and the inlet condition for the hub arrangements are kept constant. The result reveals that using twisted rectangular hub insert with different pitches will force the temperature to distribute in a circular direction. However, temperature distribution will be enhanced with the length pitch increases.

Keywords: Numerical simulation, twist arrangement, annular diffuser, temperature distribution, swirl flow, pitches.

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1161 Thermal Analysis of a Sliding Electric Contact System Using Finite Element Method

Authors: Adrian T. Pleșca

Abstract:

In this paper a three dimensional thermal model of a sliding contact system is proposed for both steady-state or transient conditions. The influence of contact force, electric current and ambient temperature on the temperature distribution, has been investigated. A thermal analysis of the different type of the graphite material of fixed electric contact and its influence on contact system temperature rise, has been performed. To validate the three dimensional thermal model, some experimental tests have been done. There is a good correlation between experimental and simulation results.

Keywords: Sliding electric contact, temperature distribution, thermal analysis.

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1160 Bidirectional Pendulum Vibration Absorbers with Homogeneous Variable Tangential Friction: Modelling and Design

Authors: Emiliano Matta

Abstract:

Passive resonant vibration absorbers are among the most widely used dynamic control systems in civil engineering. They typically consist in a single-degree-of-freedom mechanical appendage of the main structure, tuned to one structural target mode through frequency and damping optimization. One classical scheme is the pendulum absorber, whose mass is constrained to move along a curved trajectory and is damped by viscous dashpots. Even though the principle is well known, the search for improved arrangements is still under way. In recent years this investigation inspired a type of bidirectional pendulum absorber (BPA), consisting of a mass constrained to move along an optimal three-dimensional (3D) concave surface. For such a BPA, the surface principal curvatures are designed to ensure a bidirectional tuning of the absorber to both principal modes of the main structure, while damping is produced either by horizontal viscous dashpots or by vertical friction dashpots, connecting the BPA to the main structure. In this paper, a variant of BPA is proposed, where damping originates from the variable tangential friction force which develops between the pendulum mass and the 3D surface as a result of a spatially-varying friction coefficient pattern. Namely, a friction coefficient is proposed that varies along the pendulum surface in proportion to the modulus of the 3D surface gradient. With such an assumption, the dissipative model of the absorber can be proven to be nonlinear homogeneous in the small displacement domain. The resulting homogeneous BPA (HBPA) has a fundamental advantage over conventional friction-type absorbers, because its equivalent damping ratio results independent on the amplitude of oscillations, and therefore its optimal performance does not depend on the excitation level. On the other hand, the HBPA is more compact than viscously damped BPAs because it does not need the installation of dampers. This paper presents the analytical model of the HBPA and an optimal methodology for its design. Numerical simulations of single- and multi-story building structures under wind and earthquake loads are presented to compare the HBPA with classical viscously damped BPAs. It is shown that the HBPA is a promising alternative to existing BPA types and that homogeneous tangential friction is an effective means to realize systems provided with amplitude-independent damping.

Keywords: Amplitude-independent damping, Homogeneous friction, Pendulum nonlinear dynamics, Structural control, Vibration resonant absorbers.

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1159 A Study on the Heading of Spur Gears: Numerical Analysis and Experiments

Authors: M.Zadshakouyan, E.Abdi Sobbouhi, H.Jafarzadeh

Abstract:

In this study, the precision heading process of spur gears has been investigated by means of numerical analysis. The effect of some parameters such as teeth number and module on the forming force and material flow were presented. The simulation works were performed rigid-plastic finite element method using DEFORM 3D software. In order to validate the estimated numerical results, they were compared with those obtained experimentally during heading of spur gear using lead as a model material. Results showed that the optimum number of gear teeth is between 10 to 20, that is because of being the specific pressure in its minimum value.

Keywords: Heading, spur gear, numerical analysis, experiments.

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1158 Nonlinear Simulation of Harmonically Coupled Two-Beam Free-Electron Laser

Authors: M. Zahedian, B. Maraghechi, M. H. Rouhani

Abstract:

A nonlinear model of two-beam free-electron laser (FEL) in the absence of slippage is presented. The two beams are assumed to be cold with different energies and the fundamental resonance of the higher energy beam is at the third harmonic of lower energy beam. By using Maxwell-s equations and full Lorentz force equations of motion for the electron beams, coupled differential equations are derived and solved numerically by the fourth order Runge–Kutta method. In this method a considerable growth of third harmonic electromagnetic field in the XUV and X-ray regions is predicted.

Keywords: Free-electron laser, Higher energy beam, Lowerenergy beam, Two-beam

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1157 Investigation of Electrical, Thermal and Structural Properties on Polyacrylonitrile Nano-Fiber

Authors: N. Demirsoy, N. Uçar, A. Önen, N. Kızıldağ, Ö. F. Vurur, O. Eren, İ. Karacan

Abstract:

Polymer composite nano-fibers including (1, 3 wt %) silver nano-particles have been produced by electrospinning method. Polyacrylonitrile/N,N-dimethylformamide (PAN/DMF) solution have been prepared and the amount of silver nitrate have been adjusted to PAN weight. Silver nano-particles were obtained from reduction of silver ions into silver nano-particles by chemical reduction by hydrazine hydroxide (N2H5OH). The different amount of silver salt was loaded into polymer matrix to obtain polyacrylonitrile composite nano-fiber containing silver nano-particles. The effect of the amount of silver nano-particles on the properties of composite nano-fiber web was investigated. Electrical conductivity, mechanical properties, thermal properties were examined by Microtest LCR Meter 6370 (0.01 mΩ-100 MΩ), Tensile tester, Differential scanning calorimeter DSC (Q10) and SEM respectively. Also antimicrobial efficiency test (ASTM E2149-10) was done against to Staphylococcus aureus bacteria. It has been seen that breaking strength, conductivity, antimicrobial effect, enthalpy during cyclization increase by use of silver nano-particles while the diameter of nano-fiber decreases.

Keywords: Composite polyacrylonitrile nano-fiber, electrical conductivity, electrospinning, mechanical and thermal properties, silver nano-particles.

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1156 Numerical Simulation of Interfacial Flow with Volume-Of-Fluid Method

Authors: Afshin Ahmadi Nadooshan

Abstract:

In this article, various models of surface tension force (CSF, CSS and PCIL) for interfacial flows have been applied to dynamic case and the results were compared. We studied the Kelvin- Helmholtz instabilities, which are produced by shear at the interface between two fluids with different physical properties. The velocity inlet is defined as a sinusoidal perturbation. When gravity and surface tension are taking into account, we observe the development of the Instability for a critic value of the difference of velocity of the both fluids. The VOF Model enables to simulate Kelvin-Helmholtz Instability as dynamic case.

Keywords: Interfacial flow, Incompressible flow, surface tension, Volume-Of-Fluid, Kelvin-Helmholtz.

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1155 PIL Theory

Authors: A. Peveri

Abstract:

The curvature space-time by the presence of material, this deformation must present a pattern of deformation, not random. Space is uniform, elastic and any modification that occurs in one part, causes a change in another.

This deformation exists, must be a constant value and is independent of the observer, and relates the amount of matter, the force caused by the curvature of space and surface space. This unit of space is defined in this study as PIL and represents a constant area of space, deformable in the direction and sense of the center of mass of the body. The PIL is curved and connected to the center of mass of the Earth, to get to that point, through all matter, thus forming part of any place between particles at atomic and subatomic levels. At these levels the space between each particle is flat, unlike the macro where the space curves.

Keywords: Space flat, Space curved, Unit of space, Deformation.

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1154 Effect of Damping on Performance of Magnetostrictive Vibration Energy Harvester

Authors: Mojtaba Ghodsi, Hamidreza Ziaifar, Morteza Mohammadzaheri, Payam Soltani

Abstract:

This article presents an analytical model to estimate the harvested power from a Magnetostrictive cantilevered beam with tip excitation. Furthermore, the effects of internal and external damping on harvested power are investigated. The magnetostrictive material in this harvester is Galfenol. In comparison to other popular smart materials like Terfenol-D, Galfenol has higher strength and machinability. In this article, first, a mechanical model of the Euler-Bernoulli beam is employed to calculate the deflection of the harvester. Then, the magneto-mechanical equation of Galfenol is combined with Faraday's law to calculate the generated voltage of the Magnetostrictive cantilevered beam harvester. Finally, the beam model is incorporated in the aforementioned combination. The results show that a 30×8.5×1 mm Galfenol cantilever beam harvester with 80 turn pickup coil can generate up to 3.7 mV and 9 mW. Furthermore, sensitivity analysis made by Response Surface Method (RSM) shows that the harvested power is only sensitive to the internal damping coefficient.

Keywords: Internal damping coefficient, external damping coefficient, Euler-Bernoulli, energy harvester, Galfenol, magnetostrictive, response surface method.

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1153 The High Strength Biocompatible Wires of Commercially Pure Titanium

Authors: J. Palán, M. Zemko

Abstract:

COMTES FHT has been active in a field of research and development of high-strength wires for quite some time. The main material was pure titanium. The primary goal of this effort is to develop a continuous production process for ultrafine and nanostructured materials with the aid of severe plastic deformation (SPD). This article outlines mechanical and microstructural properties of the materials and the options available for testing the components made of these materials. Ti Grade 2 and Grade 4 wires are the key products of interest. Ti Grade 2 with ultrafine to nano-sized grain shows ultimate strength of up to 1050 MPa. Ti Grade 4 reaches ultimate strengths of up to 1250 MPa. These values are twice or three times as higher as those found in the unprocessed material. For those fields of medicine where implantable metallic materials are used, bulk ultrafine to nanostructured titanium is available. It is manufactured by SPD techniques. These processes leave the chemical properties of the initial material unchanged but markedly improve its final mechanical properties, in particular, the strength. Ultrafine to nanostructured titanium retains all the significant and, from the biological viewpoint, desirable properties that are important for its use in medicine, i.e. those properties which made pure titanium the preferred material also for dental implants.

Keywords: CONFORM SPD, ECAP, titanium, rotary swaging.

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1152 Thermal Property of Multi-Walled-Carbon-Nanotube Reinforced Epoxy Composites

Authors: Min Ye Koo, Gyo Woo Lee

Abstract:

In this study, epoxy composite specimens reinforced with multi-walled carbon nanotube filler were fabricated using shear mixer and ultra-sonication processor. The mechanical and thermal properties of the fabricated specimens were measured and evaluated. From the electron microscope images and the results from the measurements of tensile strengths, the specimens having 0.6 wt% nanotube content show better dispersion and higher strength than those of the other specimens. The Young’s moduli of the specimens increased as the contents of the nanotube filler in the matrix were increased. The specimen having a 0.6 wt% nanotube filler content showed higher thermal conductivity than that of the other specimens. While, in the measurement of thermal expansion, specimens having 0.4 and 0.6 wt% filler contents showed a lower value of thermal expansion than that of the other specimens. On the basis of the measured and evaluated properties of the composites, we believe that the simple and time-saving fabrication process used in this study was sufficient to obtain improved properties of the specimens.

Keywords: Carbon Nanotube Filler, Epoxy Composite, Ultra-Sonication, Shear Mixer, Mechanical Property, Thermal Property.

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1151 Influence of Inter-tube Connections on the Stress-Strain Behavior of Nanotube-Polymer Composites: Molecular Dynamics

Authors: Jianwei Zhang, Dazhi Jiang, Huaxin Peng, Chunqi Wang

Abstract:

Stress-strain curve of inter-tube connected carbon nanotube (CNT) reinforced polymer composite under axial loading generated from molecular dynamics simulation is presented. Comparison of the response to axial mechanical loading between this composite system with composite systems reinforced by long, continuous CNTs (replicated via periodic boundary conditions) and short, discontinuous CNTs has been made. Simulation results showed that the inter-tube connection improved the mechanical properties of short discontinuous CNTs dramatically. Though still weaker than long CNT/polymer composite, more remarkable increase in the stiffness relative to the polymer was observed in the inter-tube connected CNT/polymer composite than in the discontinuous CNT/polymer composite. The manually introduced bridge break process resulted in a stress-strain curve of ductile fracture mode, which is consistent with the experimental result.

Keywords: Carbon nanotube, inter-tube connection, molecular dynamics, stress-strain curve

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1150 MHD Mixed Convection in a Vertical Porous Channel

Authors: B. Fersadou, H. Kahalerras

Abstract:

This work deals with the problem of MHD mixed convection in a completely porous and differentially heated vertical channel. The model of Darcy-Brinkman-Forchheimer with the Boussinesq approximation is adopted and the governing equations are solved by the finite volume method. The effects of magnetic field and buoyancy force intensities are given by the Hartmann and Richardson numbers respectively, as well as the Joule heating represented by Eckert number on the velocity and temperature fields, are examined. The main results show an augmentation of heat transfer rate with the decrease of Darcy number and the increase of Ri and Ha when Joule heating is neglected.

Keywords: Heat sources, magnetic field, mixed convection, porous channel.

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1149 Critical Analysis of Different Actuation Techniques for a Micro Cantilever

Authors: B. G. Sheeparamatti, Prashant Hanasi, Vanita Abbigeri

Abstract:

The objective of this work is to carryout critical comparison of different actuation mechanisms like electrostatic, thermal, piezoelectric, and magnetic with reference to a micro cantilever. The relevant parameters like force generated, displacement are compared in actuation methods. With these results, helps in choosing the best actuation method for a particular application. In this study, Comsol/Multiphysics software is used. Modeling and simulation is done by considering the micro cantilever of same dimensions as an actuator using all the above mentioned actuation techniques. In addition to their small size, micro actuators consume very little power and are capable of accurate results. In this work, a comparison of actuation mechanisms is done to decide the efficient system in micro domain.

Keywords: Actuation techniques, microswitch, micro actuator, microsystems.

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1148 New Highly-Scalable Carbon Nanotube-Reinforced Glasses and Ceramics

Authors: Konstantinos G. Dassios, Guillaume Bonnefont, Gilbert Fantozzi, Theodore E. Matikas, Costas Galiotis

Abstract:

We report herein the development and preliminary mechanical characterization of fully-dense multi-wall carbon nanotube (MWCNT)-reinforced ceramics and glasses based on a completely new methodology termed High Shear Compaction (HSC). The tubes are introduced and bound to the matrix grains by aid of polymeric binders to form flexible green bodies which are sintered and densified by spark plasma sintering to unprecedentedly high densities of 100% of the pure-matrix value. The strategy was validated across a PyrexTM glass / MWCNT composite while no identifiable factors limit application to other types of matrices. Nondestructive evaluation, based on ultrasonics, of the dynamic mechanical properties of the materials including elastic, shear and bulk modulus as well as Poisson’s ratio showed optimum property improvement at 0.5 %wt tube loading while evidence of nanoscalespecific energy dissipative characteristics acting complementary to nanotube bridging and pull-out indicate a high potential in a wide range of reinforcing and multifunctional applications. 

Keywords: Carbon nanotubes, ceramic matrix composites, toughening, ultrasonics.

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1147 Analyzing and Determining the Ideal Response Force for Combatting Terrorist Groups

Authors: Erhan Turgut, Salih Ergün, Abdülkadir Öz

Abstract:

Terror is a modern war strategy which uses violence as a means of communication in order to achieve political objectives. In today’s security environment narrowing the propaganda field of terrorist organization is the primary goal for the security forces. In this sense, providing and maintaining public support is the most necessary ability for security units. Rather than enemy and threat-oriented approach, homeland security oriented approach is essential to ensure public support. In this study, terror assumed as a homeland security issue and assigning the law enforcement forces with military status is analyzed.

Keywords: Terrorism, Counter-terrorism, Military Status Law-enforcement.

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1146 An Intelligent System for Knee and Ankle Rehabilitation

Authors: Dimitar Karastoyanov, Vladimir Monov

Abstract:

The paper is concerned with the state examination as well as the problems during the post surgical (orthopedic) rehabilitation of the knee and ankle joint. An observation of the current appliances for a passive rehabilitation devices is presented. The major necessary and basic features of the intelligent rehabilitation devices are considered. An approach for a new intelligent appliance is suggested. The main advantages of the device are: both active as well as passive rehabilitation of the patient based on the human - patient reactions and a real time feedback. The basic components: controller; electrical motor; encoder, force – torque sensor are discussed in details. The main modes of operation of the device are considered.

Keywords: Ankle, knee, rehabilitation, computer control.

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1145 Improving Gas Separation Performance of Poly(Vinylidene Fluoride) Based Membranes Containing Ionic Liquid

Authors: S. Al-Enezi, J. Samuel, A. Al-Banna

Abstract:

Polymer based membranes are one of the low-cost technologies available for the gas separation. Three major elements required for a commercial gas separating membrane are high permeability, high selectivity, and good mechanical strength. Poly(vinylidene fluoride) (PVDF) is a commercially available fluoropolymer and a widely used membrane material in gas separation devices since it possesses remarkable thermal, chemical stability, and excellent mechanical strength. The PVDF membrane was chemically modified by soaking in different ionic liquids and dried. The thermal behavior of modified membranes was investigated by differential scanning calorimetry (DSC), and thermogravimetry (TGA), and the results clearly show the best affinity between the ionic liquid and the polymer support. The porous structure of the PVDF membranes was clearly seen in the scanning electron microscopy (SEM) images. The CO₂ permeability of blended membranes was explored in comparison with the unmodified matrix. The ionic liquid immobilized in the hydrophobic PVDF support exhibited good performance for separations of CO₂/N₂. The improved permeability of modified membrane (PVDF-IL) is attributed to the high concentration of nitrogen rich imidazolium moieties.

Keywords: PVDF, gas permeability, polymer membrane, ionic liquid.

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1144 The Effect of Screw Parameters on Pullout Strength of Screw Fixation in Cervical Spine

Authors: S. Ritddech, P. Aroonjarattham, K. Aroonjarattham

Abstract:

The pullout strength had an effect on the stability of plate screw fixation when inserted in the cervical spine. Nine different titanium alloy bone screws were used to test the pullout strength through finite element analysis. The result showed that the Moss Miami I can bear the highest pullout force at 1,075 N, which causes the maximum von Mises stress at 858.87 MPa, a value over the yield strength of titanium. The bone screw should have large outer diameter, core diameter and proximal root radius to increase the pullout strength.

Keywords: Pullout strength, Screw parameter, Cervical spine, Finite element analysis.

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1143 Degree of Milling Effects on the Sorghum (Sorghum bicolor) Flours, Physicochemical Properties and Kinetics of Starch Digestion

Authors: Brou K., Guéhi T., Konan A. G., Gbakayoro J. B., Gnakri D.

Abstract:

Two types of crushing were applied to grains of red sorghum: manual crushing using a mortar and pestle of kitchen and mechanical crushing using a hammer mill. The flours obtained at the end of these various crushing were filtered and subdivided in different fractions according to the diameters of the mesh of the sieves (0.16mm; 0.25mm; 0.315mm; 0.4mm, and 0.63mm…). Some physical, chemical and nutritional traits of these flours were evaluated using Association of Official Analytical Chemists (AOAC). In vitro digestibility of these flours was also studied with freezing of flour 1% like substrate and α-amylase from B. licheniformis (E.C.3.2.1.1; Megazyme, Wicklow, Ireland). The results revealed that the batches of flours which have the finest diameters as 0.16mm; 0.25mm are the richest one in nutrients and are also the most digestible. Also mechanical crushing is the best mean to obtain significant amount of flours. In conclusion, the type of crushing and the size of the particles have an impact on the final concentration of some nutrients of the flours obtained. Indeed, the finest particles (0.16mm – 0.25mm 0.315mm) obtained after sifting of the flours are more nutritive and have a better digestibility than others size. So the finest particles could be advised for management of cereals namely the sorghum for the production of the infantile foods.

Keywords: Nutrients, digestibility, crush, flour, milling, granulometry.

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1142 Myotonometry Method for Assessment Muscle Performance

Authors: Rusu Ligia, Cosma Germina, Lica Eliana, Marin Mihnea, Cernăianu Sorina, Copilusi Petre Cristian, Rusu Petre Florinel

Abstract:

The aim of this paper is to present the role of myotonometry in assessment muscle viscoelasticity by measurement of force index (IF) and stiffness (S) at thigh muscle groups. The results are used for improve the muscle training. The method is based on mechanic impulse on the muscle group, that involve a muscle response like acceleration, speed and amplitude curves. From these we have information about elasticity, stiffness beginning from mechanic oscillations of muscle tissue. Using this method offer the possibility for monitoring the muscle capacity for produce mechanic energy, that allows a efficiency of movement with a minimal tissue deformation.

Keywords: assessment, infraspinatus syndrome, kinetic therapy, rehabilitation

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1141 The Transformative Impact of Telecommunication in Africa: Connecting Nations, Empowering Lives

Authors: I. M. Mungadi, M. S. Argungu

Abstract:

This study delves into the transformative impact of telecommunication in Africa, illuminating its role in connecting nations and empowering lives across the continent. Over recent decades, the rapid expansion of telecommunication infrastructure has become a powerful force, fostering socio-economic growth and development. Beyond the exchange of information, this digital revolution has influenced education, healthcare, commerce, governance, and social interaction. The abstract explores the multifaceted dimensions of telecommunication's influence on Africa, addressing both its positive transformations and the challenges it presents. By examining the dynamic interplay between technological advancements and societal changes, this research contributes to a nuanced understanding of how telecommunication is shaping a more interconnected, informed, and empowered Africa.

Keywords: Transformative, telecommunication, nations, empowering, connecting.

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1140 Transient Currents in a Double Conductor Line above a Conducting Half-Space

Authors: Valentina Koliskina, Inta Volodko

Abstract:

Transient eddy current problem is solved in the present paper by the method of the Laplace transform for the case of a double conductor line located parallel to a conducting half-space. The Fourier sine and cosine integral transforms are used in order to find the Laplace transform of the solution. The inverse Laplace transform of the solution is found in closed form. The integrated electromotive force per unit length of the double conductor line is calculated in the form of an improper integral.

Keywords: Transient eddy currents, Laplace transform, double conductor line.

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1139 Feasibility Study of a BLDC Motor with Integrated Drive Circuit

Authors: Jun-Hyuk Choi, Joon Sung Park, Jung-Moo Seo, In-Soung Jung

Abstract:

A brushless DC motor with integrated drive circuit for air management system is presented. Using magnetic equivalent circuit model a basic design of the motor is determined, and specific configurations are inspected thanks to finite element analysis. In order to reduce an unbalanced magnetic force in an axial direction, induced forces between a stator core and a permanent magnet are calculated with respect to the relative positions of them. For the high efficiency, and high power density, BLDC motor and drive are developed. Also vibration mode and eccentricity of a rotor are considered at the rated and maximum rotational speed Through the experimental results, a validity of the simulated one is confirmed.

Keywords: blower, BLDC, inverter

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1138 Harvesting of Kinetic Energy of the Raindrops

Authors: K. C. R. Perera, B. G. Sampath, V. P. C. Dassanayake, B. M. Hapuwatte.

Abstract:

This paper presents a methodology to harvest the kinetic energy of the raindrops using piezoelectric devices. In the study 1m×1m PVDF (Polyvinylidene fluoride) piezoelectric membrane, which is fixed by the four edges, is considered for the numerical simulation on deformation of the membrane due to the impact of the raindrops. Then according to the drop size of the rain, the simulation is performed classifying the rainfall types into three categories as light stratiform rain, moderate stratiform rain and heavy thundershower. The impact force of the raindrop is dependent on the terminal velocity of the raindrop, which is a function of raindrop diameter. The results were then analyzed to calculate the harvestable energy from the deformation of the piezoelectric membrane.

Keywords: Raindrop, piezoelectricity, deformation, terminal velocity.

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