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Universal Journal of Mechanical Engineering
Number of Followers: 17  Open Access journalISSN (Print) 2332-3353 - ISSN (Online) 2332-3361 Published by Horizon Research Publishing  [54 journals]
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- Study of the Fastest Rate of Freezing Saline Solution Using Factorial
Design Method
Abstract: Publication date: May 2019
Source:Universal Journal of Mechanical Engineering Volume 7 Number 3A Nia Nuraeni Suryaman An engineer needed the ability to design an experiment research to be effective and efficient to obtain optimal results. The purpose of this experiment is to determine the fastest rate of freezing saline solution. The research process begins with determining the independent variables as much as possible and determines the three independent variables to be tested. After determine variables, and then create table factorial design to determine the research steps as much as 8 times. Then determine the most influential variables using Yates's algorithm was then tested again using response surface methodology (RSM), but for this study only uses two steps of the three step RSM. So it can be concluded that the lower temperature and salinity the faster the rate of freezing for both type of salt, Krosok and salt.
PubDate: May 2019
- Analysis of Maintenance Systems in Jet Dyeing Machine Components Using the
Age Replacement Method
Abstract: Publication date: May 2019
Source:Universal Journal of Mechanical Engineering Volume 7 Number 3A Yani Iriani and Harry Bachtiar Purpose: The purpose of this study was to determine the maintenance intervals of critical components of jet dyeing machines in an effort to minimize downtime and calculate maintenance costs for engine damage to the jet dyeing. Design/ methodology/ approach: In this study an optimization method was developed to determine the replacement interval of a critical component, namely the Age Replacement Method. Findings: Based on the results of the calculation interval obtained preventive care critical components of jet engines during dyeing 1549 hours. It means that the component must be replaced before operation for 1549 hours or there is 6 times the turnover of prevention under taken in the interval of one year and the resulting decrease in the total cost of 82%. Research limitations/ implications: A review conducted in this paper against one component only, and then it can be developed for this type of component production machines. Practical implications: If the company is implementing a policy of replacement of critical components of the engine on the jet dyeing machine with a method of age replacement, then it will occur treatment cost savings amounting to Rp. 6,752,886 lower when compared with the initial conditions the company previously Rp 37,441,132. Originality/ value: This study combines the Pareto Diagram method and the Age Replacement Method to obtain optimum maintenance scheduling.
PubDate: May 2019
- Influence of Fuel System, Fuels Types and Spark Plug Types on CO Gas
Exhaust of Motorized Vehicles
Abstract: Publication date: May 2019
Source:Universal Journal of Mechanical Engineering Volume 7 Number 3A Udin Komarudin Fuel system, type of fuel and type of spark plug, are the determining variables in producing exhaust gas in motorized vehicles. Pollutants produced by motor vehicle emissions include Carbon Monoxide (CO), carbon dioxide (CO2), Sulfur Dioxide (SO2), Nitrogen Monoxide (NOX), Hydrocarbons (HC), Lead Particles (PB), smoke and ash. These pollutants can cause interference in humans, animals, plants and other objects. The study was conducted to determine the effect of the main variables of the fuel system variables (Carburetor and EFI), type of fuel (Premium octane 88 and Pertamax octane 92) and the type of spark plugs (standard spark plugs and spark plugs Iridium) on CO gas exhaust. The test tool used to determine the value of the percentage of vehicle exhaust is a Gas Analyzer and the test vehicle used is a 4-step motorcycle. The research method uses factorial design and variable analysis using Yates's algorithm. The test results show that the effect of the fuel system is -1,272 (Carburetor), the effect of fuel type is -0,268 (Premium), and the type of spark plug is -0,018 (standard spark plug), so the most influential variable on CO gas output is the fuel system using the Carburetor.
PubDate: May 2019
- Numerical Study of Distribution Temperature and Air Flow Velocity at
Closed Type Chicken Coop for Capacity of 15,500 Chicks with Opening 1
Inlet and 4 Exhaust
Abstract: Publication date: May 2019
Source:Universal Journal of Mechanical Engineering Volume 7 Number 3A Nia Nuraeni Suryaman Udin Komaruddin Arry Hutomo and Martoni Uniformity of temperature in a room is often encountered in various purposes. This study presents the results of modeling the temperature and airflow in the chicken coop. A problem to be solved in this research is how to design the chicken coop in order to produce temperature uniformity. Thus, the objectives are to build a chicken coop dimensional model of 96x12x2 m with a capacity of 15,500 chicks. Modeling results analysis using CFD (Computational Fluid Dynamics). The stage of completion to meet the above objectives is by measuring the dimensions of the chicken coop. The next data to be obtained are temperature and air velocity to determine the boundary conditions. Some of the above parameters are used to validate chicken coop design. Modeling conducted using CFD methods with temperature and air velocity as boundary conditions. The modeling results showed that the average temperature in the chicken coop is adequate as an ideal temperature standard for chicken coop. Temperature uniformity is obtained by variation of the exhaust opening 4.
PubDate: May 2019
- Analysis of the Effect of Round, Feeding and Coolant on Surface Roughness
in the Processing of Combination Using Factorial Design
Abstract: Publication date: May 2019
Source:Universal Journal of Mechanical Engineering Volume 7 Number 3A Martoni and Marisa Hirary Experimental studies to see the surface roughness of the turning process have been carried out. The study was conducted to determine the effect of the main variables and the relationship of variables to surface roughness (modeling). The variables carried out were feeding (f), spindle rotation (n) and coolant. Material Specimens use St-37 with cylindrical dimensions. Test specimens were made using conventional lathes, HSS cutting tools and roughness tests were performed with using a Surfcorder (Surface Roughness Measuring Instrument) SE 1700
. The research method uses factorial design, variable analysis using Yates's algorithm and modeling using Least Square statistics. The test results show that the most influential variable is feeding, f = 4,957 m, where the biggest roughness occurs at conditions f = 1.2912 m / min, n = 640 rpm and without cooling media. The modeling results show that surface roughness is a function of feeding and velocity, Ra = f (f, n), (Ra = 5.2024 f + 0.0048n), the higher the feeding and speed, the greater the surface roughness.
PubDate: May 2019
- Energy Production Assessment of Solar Tower Based on the Study of the
Mirror Shadowing and Blocking Effects
Abstract: Publication date: Mar 2019
Source:Universal Journal of Mechanical Engineering Volume 7 Number 2 Saad S. Alrwashdeh Concentrated solar energy systems are one of the most important applications of solar energy, which will have a promising future in Jordan that because of Jordan has more than 300 sunny days with a high rate of solar radiation. In this research, the phenomenon of blocking and shadowing of mirrors in the solar field and their effect on the production of energy from the solar tower was examined and found that the mirrors far from the solar tower are affected in these phenomena significantly unlike the nearest mirrors.
PubDate: Mar 2019
- Optimization of Turning Process and Cutting Force Using Multiobjective
Genetic Algorithm
Abstract: Publication date: Mar 2019
Source:Universal Journal of Mechanical Engineering Volume 7 Number 2 Afrim Gjelaj Besart Berisha and Fidan Smaili Application of artificial intelligence in manufacturing process has great impact factor. This work paper is focused into optimization of machining by turning process regarding to the analysing of tool selection (TS), tool path length (TPL) and machining parameters for turning operation using the artificial Intelligence. Except of solving of problems for tool selection and tool path length, here also will be analysed the cutting force (Fc) by turning process whereas as case of research material is steel C45. The results of measurement of the main cutting force Fc, are compared and predicted in theoretical and practical way. Also, all of requirements are fulfilled in regard of the expression. In same time are optimized the main machining parameters regarding to the cutting force with utilization of the Multi-Objective Genetic Algorithm (MOGA). Results for cutting power Pc and Metal removal rate MRR using Pareto Front are obtained using MOGA.
PubDate: Mar 2019
- Structural Synthesis of Robot Manipulators by Using Screw with Variable
Pitch
Abstract: Publication date: Mar 2019
Source:Universal Journal of Mechanical Engineering Volume 7 Number 2 Rasim Alizade This paper focuses on the systematic type synthesis of parallel robot manipulators by using new structural formulas based on the screw theory. New structural formulas as a total number of screw in kinematic pairs
, number of screws with variable pitch 
, total number of screws that represent the contact geometry of lower and higher joint elements (t), mobility equation for robot manipulators (M), dimension of the closed loop 
, motion of end effector of parallel manipulator 
, number degree of freedom of kinematic pairs 
, refers to find the kinematic structure of robot manipulators realizing a specified motion requirement. Twenty kinematic pairs with structural parameters 
are introduced. History of six structural formulas using for structural synthesis of parallel robot manipulators from space and different subspaces are presented as a table with equations, authors, years and some commentaries. The structural synthesis approach is based on the elementary notions of screw theory. Using the proposed of structural formulas approach, families of platform manipulators are constructed from a set of structural units. This paper is appropriate for engineers with interest in robotics, rovers, space docking parallel manipulators and screw theory.
PubDate: Mar 2019
- Air to Air Energy Recovery from HVAC Systems under Different Membrane
Materials
Abstract: Publication date: Mar 2019
Source:Universal Journal of Mechanical Engineering Volume 7 Number 2 Rafat F. Al-Waked and Mohammad S. Nasif Membrane heat exchanger is one of the main components of green HVAC systems. Performance of a thin-membrane heat exchanger has been examined for different membrane materials. A computational fluid dynamics (CFD) approach was utilized to conduct the current study. The CFD model consisted of a single channel for hot stream and another channel for cold stream. Four membranes were investigated: 45 gsm and 60 gsm Kraft paper, modified cellulose acetate membrane and PVA/LiCl blend membrane. Obtained values of thermal effectiveness at typical HVAC system conditions showed that different membrane materials produced different thermal performance values. The amount of energy recovered from the modified cellulose acetate membrane heat exchanger was the highest. Finally, heat exchanger performance is found to be very sensitive to ambient air relative humidity variation.
PubDate: Mar 2019
- A Contemporary Concept in Troubleshooting and Fixing Malfunctions Using an
Engine Room Simulator in Augmented Reality Environment
Abstract: Publication date: Mar 2019
Source:Universal Journal of Mechanical Engineering Volume 7 Number 2 Ivaylo Bakalov Engine simulators are used to achieve the critical educational objectives in training the ship's crew. The simulators provide a complete scientific insight into systems, engines, machinery and everyday operation, as well as detection and fixing of problems. In addition, engine room simulators help teamwork, adaptation to different situations, and decision-making in a crisis situation. An exercise for seafarers was developed in a virtual LNG Carrier with Steam Turbine as main engine in the ERS TehSim 5000 simulation complex. The participants are divided into different teams: - for engine room team, and technical team. The exercise was developed on the basis of the ability of the marine engineers' training complex and the LNG Carrier vessel model on the simulator. The exercise consisted of work on the ship's steam system on LNG Carrier mixed with a real failure on the steam line. The engine room team operates on the simulated complex, and the technical team is dealing with the real work until troubleshooting. The exercise consists of: work on a real check list to start the power system; alarm sound; real work on the problem; implementation of emergency response procedures. The working staffs of the exercise are Greek students – fourth year mechanics, with experience of LNG Carrier.
PubDate: Mar 2019
- Endurance and Damage in Fatigue of Symmetrical Configuration 2P-2V-2P
Perlon-Glass-Acrylic Composite Laminates of Orthopaedic Use
Abstract: Publication date: Jan 2019
Source:Universal Journal of Mechanical Engineering Volume 7 Number 1 Bachir Redjel and Sihem Achouri In this paper, an experimental characterization of fatigue behaviour on prismatic specimens of a symmetrical laminated composite material perlon- glass- acrylique 2P-2V-2P for orthopaedic use is conducted. Cyclic repeated solicitation is employed corresponding to applied minimum stress σmin equal zero. The various loading levels imposed on the specimens are 80%, 70%, 60%, 55%, 45%, 35% and 25% of the value of the static failure strength measured in flexure. A significant scatter characterizes the results of material fatigue lifetime. That is the consequence of the heterogeneity of the material structure. The scattered phenomenon prevents any prediction of the lifetime with a good probability using Wohler equation. This enables defining a constant degradation rate by 10% cycle decade. The microstructure morphology study through microscopic observations is also discussed and analyzed. The damage state in fatigue is characterized by a combination of density and orientation of micro-cracks. This damage is mainly due to mechanisms complexity of matrix micro-cracking, inter facial exfoliation, debonding and delamination. The damage evolution stages in the case of cyclic loading have the same nature than those found in static loading but have different chronology and scale.
PubDate: Jan 2019
- Mechanical and Thermodynamic Properties of Half-metallic Ferromagnetism
Containing Cobalt and Titanium
Abstract: Publication date: Jan 2019
Source:Universal Journal of Mechanical Engineering Volume 7 Number 1 I. Asfour D. Rached Ababou Girard soraya and Sébilleau Didier We have studied the structural, electronic, elastic, magnetic and Thermodynamic properties of Co-based full-Heusler alloys Co2TiSi and Co2TiGe. have been studied by first-principles full-potential linearized augmented plane wave (FPLAPW) method with the Generalized Gradient Approximation (GGA) based on density functional theory (DFT). This shows that the magnetic properties of the compound are dependent on electron concentration of main group element and all compunds are magnetic in their equilibrium L21 structure. The electronic structure report that, our compounds have half-metallic (HM) nature. The mechanical results show that these compounds are mechanically stable. and exhibit 100% spin polarization at the Fermi level where it can be shifted within the energy-gap. In addition, the quasi-harmonic Debye model is applied to determine the thermal properties of the alloy.
PubDate: Jan 2019
- Pull-in Effect for Micro Beam with Tensile Force
Abstract: Publication date: Jan 2019
Source:Universal Journal of Mechanical Engineering Volume 7 Number 1 Skubov D. Yu. Privalova O. V. and Shtukin L. V. Recent time the development and achievement of micro- and nano-electromechanical systems (MEMS and NEMS) are appeal the great interest of physics, biologists, engineers-electricians. The designing of MEMS based on pull-in effect consists in interaction of electrostatic field with thin elastic conductive beam. This interaction leads to pull-in instability – the effect of collapse of two initially parallel conductive layers, which play the role of capacitor. The important significance of MEMS have been acquired [1, 2] such, for example, as micro-switches with forward or rotary movement. These devices may be membrane else cantilever or another type, also high speed rotational actuator – contactless micro-gyroscope.
PubDate: Jan 2019
- Pseudorandom Noise Impulsive Response Analysis and Aerodynamic Forces of
Unmanned Aerial Vehicle Structure
Abstract: Publication date: Jan 2019
Source:Universal Journal of Mechanical Engineering Volume 7 Number 1 Mohammed D. Salman Kadim Karim Mohsen and Aiman Basem Abttan This paper concentrated about the effect of both the pseudorandom or random vibration (wind waves) and aerodynamic forces on the wing of unmanned aerial vehicle, which brought the attention of specialists in this field during last years, the performance of wing is improved on a definitive solution for the vibration problems which cause failure in the wings of UAV. The distribution of stresses and distortions with aerodynamic loads is studied. Factors such as tension, pressure and shear stress showed on wing of UAVs due to vibration which caused the structure of wing to break down and then failure. The experimental study was carried out by using wing made of composite material (foam and cover by lamination plate), where airfoil type (NACA Clark y) installed inside wind tunnel of low velocity. It is found that the vibration acceleration at constant wind velocity with variation of attack angle of the wing, it is obtained the relationship between the acceleration and the frequency using the LABVEIW program which analyzed and identified the distribution of forces on the wing. The stress concentration areas is created and found under failure occurs, the aerodynamic force, torsion torque and magnitude of deformation is calculated. It is concluded that the close areas from the root wing (fixed end) is most likely to collapse or break.
PubDate: Jan 2019
- Expansion of Wave Rays and Fronts in Media with Inhomogeneous Structure
Abstract: Publication date: Sep 2018
Source:Universal Journal of Mechanical Engineering Volume 6 Number 4 Anatoli Chigarev and Ju. Chigarev In the article on the principles of Fermet, Huygens obtaine the differential equations in the form of Hamilton, which describe the ray trajectories and wave fronts in inhomogeneous media. Established that the vector of Poynting-Umov's determining the direction of energy propagation in inhomogeneous medium is coincident with the vector tangent to the ray. In the second part of the article established that the equations of the theory of rays' propagation in inhomogeneous media have the form of equations of nonlinear dynamics and describe the emergence of deterministic chaos in the geometry of rays for a wide variety of types of heterogeneous structures. In this case, the rays behave randomly and their description you must go to the description based on the theory of random functions and fields. In the third part of the paper is considered a model which is equivalent to the random medium and the calculation of the coordinates of the ray (the mathematical expectation and correlation functions). Understanding of these characteristics gives information about the behavior of the trajectories of the rays for these models of media. The description of the behavior of rays on the basis of the equations of statistical mechanics is discussed in the article for functions of Markov's type.
PubDate: Sep 2018
- Experimental and Numerical Study of Heat Transfer Process of Chilled Water
Storage Tank
Abstract: Publication date: Sep 2018
Source:Universal Journal of Mechanical Engineering Volume 6 Number 4 Firas M. Hasan and Maathe Abdulwahed Theeb Cool thermal energy storage using thermal stratification becomes one of the widespread applications because of the ability to shift the electrical cooling loads from on-peak to off-peak periods and significantly contributes to reducing the capacity of the refrigeration system and operating costs. Seven flow rate tests varying from 1.5 to 7.5 l/min for charging cycle were performed on small-scale vertical cylindrical storage tank equipped with three primary inlet diffusers, an elbow, two-ring linear and radial circular diffusers. The storage tank with inlet diffusers was assessed using temperature distributions and performance measures including thermocline thickness(ht), the half-cycle figure of merit (
) and equivalent lost tank height (ELH). Commercial finite volume code was used to predict temperature distributions in a stratified water tank model, temperature data acquired from experimental tests and simulation models were compared for validation purpose. The results suggested that the storage tank with two-ring linear circular diffuser produced better performance and higher stratification than two-ring radial circular diffuser for various flow rates by 1.4% , 20.6% ELH and 10.6% ht, and much better than an elbow diffuser by 1.7% , 24% ELH and 31.1% ht, furthermore, the degree of mixing was affected essentially the flow velocity which in turn causes an increase or decrease in thermocline thickness. Temperature distributions obtained from finite volume model are found to be in very close agreement with those obtained experimentally.
PubDate: Sep 2018
- Numerical Study of the Heat Transfer Rate of Nano-fluid Flow in a Channel
with a Triangular Cross-section in the Presence of a Magnetic Field
Abstract: Publication date: Sep 2018
Source:Universal Journal of Mechanical Engineering Volume 6 Number 4 Amir Haghighatkhah Hossein Ahmadi-Danesh-Ashtiani and Kourosh Amiraslani In this study, nanofluid flow inside a triangular channel in the presence of a magnetic field with two phase model was analyzed. For this purpose, the external surface of the channel is heated or cooled with a specific heat transfer coefficient, and the effect of the changes in the Nusselt number as well as the pressure drop for variable parameters such as nanoparticle concentrations, magnetic field strength, and channel shape (relative to the circular mode) was investigated. In order to the Grid Independent Study, the Nusselt number for different sizes of grid has been evaluated. As a result, comparing the Nusselt number changes, the average is seen by changing the size of the networking. A grading with the number of 350,000 elements is suitable for simulating the corresponding problem. In order to confirm the validity of the results, simulation of Nusselt number changes during the channel was evaluated and compared with the results presented by Saeed et al. [23]. The error rate between the data presented in reference [23] and the simulation claims is not tangible, and therefore the model used for simulation has been approved. In this study, a triangular channel with a flow inside it is a nanofluid, is analyzed in the presence of a magnetic field in a smooth, completely two phases. For this purpose, the external surface of the channel with a certain heat transfer coefficient and the effect of changes in the thermal and fluid parameters with the change in the parameters involved in the problem have been observed. The results show that with increasing magnetic field, friction coefficient, in-channel velocity, heat transfer rate, average Nusselt number increase. In this study, for simulation we used computational fluid dynamics and limited volume method, and specifically using the Ansys-Fluent version 17 software. The problem is investigated in the form of a three dimensional, stable, single-phase and two-phase flow.
PubDate: Sep 2018
- Influence of the Mills Maintenance on Their Capacity
Abstract: Publication date: Nov 2018
Source:Universal Journal of Mechanical Engineering Volume 6 Number 5 Lidija Joleska Bureska The good working condition of the mills is very important for boilers, which use coal dust. The mills are very important for Power Plants because their work have a direct influence on the combustion process in the boiler furnace. On time controlling the mills condition and their correct repairing during a revision in accordance, technical standards enable unhindered work of the mills with a maximal load. Depending on the coal quality, a maximal load of the mills directly enables increasing of the heat in the boiler. In continue of the paper are shown the characteristic, parameters and capacity of the fans mills during tests: before overhaul (with current maintenance, with partial reparation with a lot of shortcomings) and after overhaul (with complete reparation). According to the received results, a comparative analyze was made for the effect of the mills' condition on the capacity of the boiler and of course of the Power Plant. In order to reach better characteristics of the mills, at the end of paper are mentioned measures for increasing mills‘ capacity for 20t/h with execution technically properly overhaul, with elimination on all gaps in the mills, with improving sealing on the whole coal line etc.
PubDate: Nov 2018
- A Tissue Engineering Discussion for Mechanical / Chemical Engineers -
Introducing the Operation of the Stem-Cells Activation Triggers
Abstract: Publication date: Nov 2018
Source:Universal Journal of Mechanical Engineering Volume 6 Number 5 Edilson Gomes de Lima This paper traced an introductory script about the natural communication by an interface between the tissues and the environment theoretically, as a possible form of biological adaptation in environment, as a first step for popularization in tissue engineering for mechanical and chemical engineers. Knowing the keys communication system, it’s theoretically possible to understand that even after generating a specialized tissue, it is still possible to induce new stem cells to generate tissues. According to external and internal tissues readings, as by integrin mechanism, or actomyosin induced by various means, presented throughout this study. Also, make visible and clear new stem cells induction techniques through stimuli, activated by means for the formation of specialized and interconnected specialized cells for tissue engineering. In this objective investigation is showed some mechanical analytical apparatus in new designs to automate biological processes. The domain of all flow and mechanism in stem cell activation triggers is as important as the knowledge of DNA sequencing. With the focus on proving the ability of the tissues to read passively, interpret the external environment and make changes by biochemicals for appropriate adaptation, the genes interpret the environmental stimuli, human senses interfaces and activate adult stem cell niches. External factors along the stem cell are the focus of this investigation, e.g. it has already been proven that a specific nanotopography is a platform to induce differentiation control in stem cells. By nanotopography a stem cell can being induced to become a specific tissue. Through the control and listing these activation keys through mechanical engineering and logic, we can create true artificial tissue factories in high precision innovative scaffolds geometries, with final objective new addictive manufacture and innovative architecture for biological circuits.
PubDate: Nov 2018
- A Numerical Algorithm for the Analysis of the Thermal Stress-Stain State
of a Rod
Abstract: Publication date: Nov 2018
Source:Universal Journal of Mechanical Engineering Volume 6 Number 5 Kanat Amirtayev A universal algorithm for solving applied tasks of thermo elastic state of a partially heat insulated rod of limited length, in the presence of axial force, temperature, heat flow and heat exchange, was developed. The corresponding numerical calculation of efforts of the rod partially thermally insulated and clamped by two ends, in the presence of heat flow was elaborated. The numerical algorithm allowed calculate the lengthening value of the partially thermally insulated rod or the compressive stress and strain in the rods of limited length with the heat flow, the heat exchange, heat insulation and the axial tensile force.
PubDate: Nov 2018
- Optimal Synthesis and Implementation of Resonant Vibratory Systems
Abstract: Publication date: Mar 2018
Source:Universal Journal of Mechanical Engineering Volume 6 Number 2 Volodymyr Gursky Igor Kuzio and Vitaliy Korendiy The problems of synthesis and substantiation of elasticity parameters of the resonant vibratory device with electromagnetic drive and one flat spring are considered. At first, the harmonic systems with oscillation frequencies of 50 Hz and 100 Hz were investigated. Then, various asymmetric piecewise linear characteristics of elasticity were carried into effect on one flat spring using auxiliary intermediary fixed cylindrical supports. Due to this, the corresponding vibro-impact operation modes were obtained. The resonant systems characterized by improved functioning efficiency were carried into effect using the new technique of optimization synthesis of elasticity parameters. The resonant systems being investigated were implemented in practice. The basic experimental investigations of their kinematic, dynamic and energetic parameters were carried out. The fundamental result of the investigation consists in confirmation of the improved dynamic efficiency of vibro-impact systems with pulsed electromagnetic excitation designed according to the new technique. The proposed systems may be used in technological processes of materials compaction and screening, of surface treatment of machine parts and in processes associated with nanotechnology.
PubDate: Mar 2018
- First Principles Study of the New Half-metallic Ferromagnetic Full-Heusler
Alloys Co2CrSi1-XGeX: An Ab-initio Study
Abstract: Publication date: Mar 2018
Source:Universal Journal of Mechanical Engineering Volume 6 Number 2 I. Asfour and D. Rached We present an ab-initio study of the structural, electronic, elastic, magnetic, thermal and thermodynamic property of the quaternary Heusler alloys
(x = 0, 0.25, 0.5, 0.75, 1) with the linearized augmented plane wave method based on density functional theory (DFT) and implemented in WIEN2k code. For exchange correlation potential we have used the generalized gradient approximation (GGA) of Perdew et al. Our results provide a theoretical study for the mixed Heusler 
in which no experimental or theoretical data are currently available. In their equilibrium L21 structure, all concentrations are equilibrium L21 structure; all concentrations are magnetic and metallic. However, there is linear variation of the lattice parameter. The bulk modulus, the elastic constants and the Debye temperature was studied with variation of composition x of Ge. A regular solution model is used to investigate the thermodynamic stability of the alloy which is essentially shows a miscibility gap phase by calculating the critical temperatures of the alloys. In addition, the quasi-harmonic Debye model is applied to determine the thermal properties of the alloy.
PubDate: Mar 2018
- Human Machine Interface Design for a 3 DoF Robot Manipulator
Abstract: Publication date: Jul 2018
Source:Universal Journal of Mechanical Engineering Volume 6 Number 3 Fatih Cemal Can Önder Lapçin Burak Ayan and Mehmet Çevik This paper represents a Human Machine Interface (HMI) design to control a 3 DoF robot manipulator. This manipulator has two parallelograms to make the moving platform always parallel to the ground. We used inverse kinematic analysis of the robot manipulator to control the end point location. Inverse kinematic results are verified using design parameters and end effector location. According to our algorithm, user defines the end point location from HMI, and then program solves inverse kinematics of the robot manipulator. The angles are sent to Arduino microcontroller to set the position of the servo motors. Using this HMI, the user picks and places the object in real time. The user can also give command to draw linear, circular and rectangular paths on the HMI.
PubDate: Jul 2018
- Simulation of Tsunami Effect by Seismic Wave Propagation in Hypoplastic
Medium at Vicinity of Free Boundary
Abstract: Publication date: Jan 2018
Source:Universal Journal of Mechanical Engineering Volume 6 Number 1 Anatoli Chigarev Victor Polenov and Pavel Shirvel A theoretical study of seismic waves propagation in a soil layer with a free surface has a great importance for a prediction in engineering decisions. Wave packets are radiated from an earthquake source and transfer energy. A transformation and a selection of wave packets occur in a process of wave propagating that why waves which arrive in a layer have a length considerably greater than a variation scale of heterogeneity in a medium in a layer near free surface. In the case, when the properties of different layers affect a relatively small degree on a behavior of the waves, an approximation of effective medium gives a fairly good solution. A model of a hypoplastic medium is used for a describing of some effects, which are observed in the time of seismic wave propagation. The model of hypoplastic medium allows describing many effects which are observed in granular soils. We consider a successive application of effective medium and ray methods in order to receive of approximate analytical solutions wishing to describe shear wave propagation in stratified layer, which lies on a half-space.
PubDate: Jan 2018
- Experimental Investigation of Flow Structures around a Torpedo-like
Geometry Placed in a Boundary Layer Flow
Abstract: Publication date: Jan 2018
Source:Universal Journal of Mechanical Engineering Volume 6 Number 1 M. A. H. Hayder I. Goktepeli S. Yagmur M. Ozgoren F. Kose and L. A. Kavurmacioglu Defense applications for both under oceans and seas, particularly underwater vehicles have been considered in this research. With this aim, flow characteristics around a torpedo-like geometry under the effect of the boundary layer flow over a smooth flat plate have been experimentally examined by using PIV technique. All of the experiments have been done for Re=20000 and Re=40000 based on the length (L) of the geometry as a characteristic length. As a result, time-averaged streamwise velocity components
, velocity vectors 
, streamline topologies and Reynolds stress correlations 
in the wake region of the torpedo-like geometry have been acquired in the range of 0 ≤ G/D ≤ 1.5. Here, G is the space between the bottom point of the geometry and flat plate surface; D stands for the diameter of the geometry. It is found that at the smallest value of G/D=0.25, jet-like flow occurs between the plate and the model which causes a powerful scouring. As the gap ratio is increased to G/D=0.5 and G/D=1.0, the jet-like flow diminishes slightly and then the flow structure in the wake region becomes similar to the uniform incoming flow condition for G/D=1.50. Due to the effect of the jet-like flow and boundary layer flow, time-averaged flow patterns present asymmetrical distributions which are clearly shown a bigger size focus close to the plate in streamline topology. Reynolds stress patterns form more powerful viscous forces in the boundary layer flow due to the occurrence of eddy vortices and viscosity effect. It is observed from the aforementioned flow patterns that interaction between the flow structure, the model and boundary layer flow yields very complex structure. In order to decrease the energetic flow in this condition, passive or active flow control method can be integrated on the torpedo-like geometry.
PubDate: Jan 2018
