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Aims and Scope
Editorial Board

1. Influence of the number of cells on the stress distribution in a running PEM fuel cell stack

Maher A.R. Sadiq Al-Baghdadi

Fuel Cell Research Center, International Energy and Environment Foundation, Najaf, P.O.Box 39, Iraq.

Abstract: Mechanical degradation is often studied in single-cell proton exchange membrane (PEM) fuel cell stack models in assembly process. This however, can increase substantially when moving from assembly process to operation conditions; and also from single-cell to multiple cells. In this study, PEM fuel cell stacks consisting of 1, 3, and 5 cells with an active area of 25 cm² per cell have been simulated in operation mode. Three dimensional non-isothermal solid mechanics-CFD model of a PEM fuel cell stack, integrating the real full scale geometry of all components have been used to study the influence of the number of cells on the stress distribution in a running PEM fuel cell stack. Simulation of a running multi cells stack was successful and has not been previously seen in literatures work. The results showed that the center of the electrode tends to un-displacement. This un-displacement area increases by increasing the clamping torque. The deformations in the stack components during operation were about ten times higher than during assembly process. During assembly process, the increasing in the number of cells increases the total displacement distribution. These status were different during operation, the increasing in the number of cells enhances the uniformity of the total displacement. Increasing the number of cells enhances the uniformity of the mechanical state. The better contact pressure homogeneity was obtained with the greater number of cells and leads to the lower contact resistance. In general, the results showed lower stresses values with lower distributions and more homogeneous and uniformity in the stack that consisting of multi cells.

Volume 9, Issue 2, 2018, pp.103-128.

2. Selective electrochemical removal of monovalent and divalent ions from seawater

Utsav Raj Dotel^1,2, Erik Dirdal^1,2, Magne Olav Sydnes¹, Ingunn Westvik Jolma³,  Hans Urkedal², Tor Hemmingsen¹

1 Department of Mathematics and Natural Science, University of Stavanger, NO-4036 Stavanger, Norway.

2 Deox AS, Prof. Olav Hanssens vei 7A, NO-4021 Stavanger, Norway.

3 Energy Department, International Research Institute of Stavanger (IRIS), Prof. Olav Hanssensvei 15, NO-4021 Stavanger, Norway.

Abstract: Selective removal of monovalent and divalent ions from ternary solution, synthetic seawater, and real seawater is studied in an electrodialysis cell with iridium oxide as anode and cathode. The experiments were performed at two different current densities, 10 A m-2 and 100 A m-2. Sulphate was found to be difficult to remove at the lower current density (10 A m-2) while the cations were removed more efficiently at both current densities. The size, charge, and concentration of ions were found to be the main factors influencing the selective removal of monovalent or divalent ions. Scale formed in the recirculated electrolyte in the concentrate chamber could be removed upon treatment with 0.1 M citric acid.

3. Estimation of emissions of volatile organic vapors from parameters measured in a fuel loading terminal

Eduard J. Krummenauer¹, Elton G. Rossini¹, José de Souza², Alexandre Beluco³

1 Universidade Estadual do Rio Grande do Sul (UERGS), Porto Alegre, RS, Brazil.

2 Fundação Liberato Salzano Vieira da Cunha, Novo Hamburgo, RS, Brazil.

3 Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.

Abstract: In this work, an estimate of the emissions of volatile organic vapors emitted at a gasoline loading terminal is presented, in the absence of a vapor recovery unit. The estimation of the emissions is evaluated by the application of the General Law of Ideal Gases, using data measured in situations of fuel loading. A total of 3800 tank truck compartment samples were collected, totaling a loaded volume of 33 161 838 liters of gasoline for about 282 hours of operation in 21 days, or in three operating weeks. The results obtained provided a first estimate of the reduction of the environmental impact, evaluated by the reduction of the mass of evaporated gasoline and the registration in a database, for the execution of future projects.

4. Reaction kinetics modeling of hydrothermal carbonization

P. Kladisios, A. Sagia

Laboratory of Heat Transfer and Thermal Processes, School of Mechanical Engineering, National Technical University of Athens, Greece.

Abstract: Hydrothermal carbonization (HTC) is a thermochemical pretreatment process suitable for the valorization of biomass. It emulates the natural coalification and its main product, hydrochar, is a solid carbon-rich product that has a calorific value similar to that of lignite. The relatively low reaction conditions, the capability of the process to handle organic materials with high moisture content and the appealing properties of hydrochar render HTC a highly promising field. However, the reactions that take place are complex and partially understood. Several attempts have been made to develop reaction kinetics schemes in order to model the carbonization of specific types of biomass. In the present paper, two proposed models are examined and suggestions are made for the advancement of the process.

5. Modeling and simulation of 1mw grid connected photovoltaic system in Karbala city

Afaneen A. Abbood¹, Mohammed A. Salih², Ashraf Y. Mohammed¹

1 Department of Electrical and Electronic Engineering, University of Technology, Baghdad, Iraq.

2 Planning and Studies Department, Ministry of Electricity, Baghdad, Iraq.

Abstract: The increment of electricity demand in last few years and the wide difference between generation and load, led to support the national grid with additional generations, solar power is becoming most popular in generation sector because it is clean, inexhaustible, dependable and available in all sizes in addition of its capital cost is continuously decreases. It has also become more efficient since the power conversion efficiency of converters devices and photovoltaic solar cells has increased. This work proposes a design of 1MW grid connected Photovoltaic system under Iraq climate condition. The work contains a studying the solar radiation estimations, system technical design, system losses estimations, environmental impact, performance and economic evaluations for this system. From the obtained results, it was found that the city has good solar radiation to build PV systems in large scales, the estimated energy produced about (1757.8 MWh) produced in the first year and reach to 40,445 MWh for the total life cycle with performance ratio varied between 86.4% to 73 % and average capacity factor 19.83%. The system the system will save about 27794 tons of CO₂ emission during total life. The financial analysis shows that the levelized cost of energy is around 0.0289 $/kWh which is economically feasible.

6. Investigate the surface properties of Ti6Al4V alloy for prosthetic implants through coating by Tio2 using dip coating technique

Dunya Abdulsahib Hamdi^1,2, Zahraa Kamil¹

1 Department of Prosthetics & Othotics Engineering, Al Nahrain University, Baghdad, Iraq.

2 Surface Analysis and Materials Engineering Research Group, School of Engineering and Information Technology, Murdoch University, Murdoch, WA 6150, Australia.

Abstract: Physicochemical properties, surface topography and mechanical test of thin film TiO2 deposited on Ti-6Al-4V alloy substrates using dip coating were examined. The results obtained provided complete information on the structure of the produced materials. Thickness of double layer (59µm) used to examine. Optical microscopy for double layer shows the grain boundary reduced with increasing thickness of film and uniform distribution. X-ray diffraction proved that the film TiO2 crystalline form with major Rutile phase high intensity peaks (110,101 and 211) at 2θᵒ (27.4, 35.5 and 54.5) respectively. Scanning Electron Microscopic confirms the particle size in the range of nano-meter ~ (184-280 nm), and the gaps smaller than (600nm) on the surface will readily help to absorbs the proteins which constitute an origin of bone tissue. Using polymer PVB help to increasing addition between coated, substrate and create porous on the surface coated which is necessary for the interface growth between coated and bone tissue for implant in a human body. Energy Dispersive X-ray spectroscopy, shows the presence of TiO2 from chemical concentration, the increasing in value of Ti and O belong to coated TiO2 layer lead to increasing these weight concentration and intensity. Vicker’s Micro Hardness test used to study mechanical structure, titania coating hardness various parabolic with change in thickness of film which increasing at increasing it. The growth of thicker films could improve mechanical resistance by increasing the amount of material available to hold the loads. TiO2 gives better results that is suitable for orthopaedic implants.

7. Modeling of fitting of below knee prosthesis with self-suspension socket

Mahmud Rasheed Ismail ¹, Nadhim Nasser Nadhim ²

1 Prosthetics and Orthotics Engineering Dept., Al Nahrain University, Baghdad, Iraq.

2 Mechanical Engineering Dept., Al Nahrain University, Baghdad, Iraq.

Abstract: In this work, a mathematical model for investigating the fitting of self-suspension Below Knee (BK) prosthesis was attempted. The model is based on linkage kinematic and kinetics analysis of the residual limb segments as well as the stresses analysis at the stamp-socket interfacing. The prosthesis socket and the residual limb are approximated as combined two thick cylinders with shrinkage at interface. Lames equations of hoop and longitudinal stresses are applied with specific boundary conditions. The main parameters investigated in this model are; locomotive speed, swing phase of gait cycle, socket material, skin status and prosthesis weight. A map is constructed to investigate the effect of these parameters on prosthesis suspension fitting. The theoretical results are checked experimentally by using force platform and treadmill tests. A patient wearing BK prosthesis is participate in the experiments. KINOVA video analysis program is used for analyzing gait cycle. MATLAB Rb2013a program is used for solving the theoretical equations and plotting the results. It was found that; the suspension of the socket decrease as the walking speed increase within 1.5 to 12 m/s, skin sweating and dirty reduces the suspension force and increasing the risk of socket slippage, The more dangerous region of slip in socket occurs at mid- swing for the most of walking speeds and increasing the shrinkage fitting increase the suspension action.

8. Effect of chemical solutions on the mechanical properties of nano-silica reinforced (glass/Kevlar) fabrics polyester hybrid composite materials

Hamza M. Kamal, Mohammed J. Kadhim

Materials Engineering Department, Al-Mustansiriyah University, Baghdad, Iraq.

Abstract: Polymer matrix composite structures can be exposed to a variety of severe corrosive environments during their service, which lead to degrade their structure and deteriorate their properties. The both influence of the alkaline and acid solutions on the mechanical properties of the hybrid polymer composite materials are illustrated in this paper. Hardness, tensile properties and impact strength of the nano-silica particles reinforced (glass/Kevlar) fabrics polyester hybrid composite before and after immersing in (HCl) and (NaOH) solutions studied. Regardless of the solution, hardness, tensile and impact strength decrease with increasing the exposure time. On the other hand, the alkaline solution led to high decreasing in these properties than the acid solution. In addition, the hybrid composite showed remark enhanced in the mentioned properties than the glass fiber polyester alone.

9. Study into vibration characteristic of isotropic hyper composite material beam with various supported conditions

Aziz Darweesh Al-Mawash

University of Kufa, Mechanical Engineering Department, Iraq.

Abstract: The composite materials are very impartment materials. Since, many structures are using its materials, because, its materials have higher strength and low weight. Therefore, in this paper selected the vibration objected for beam of studying. There, the vibration characterization as natural frequency was investigation in this work with various volume fraction effects, for hyper composite materials beam. The composite material is combined from material of polyester resin and two type’s reinforcements, first short reinforcement fibre and second powder reinforcement. The different of volume fraction reinforcement of powder effect on the natural frequency of isotropic hype composite material beam is investigation. Where, the study is investigated by experimental and numerical techniques. The experimental work included calculated the natural frequency of hyper composite beam with different volume fraction of reinforcement powder, and also, evaluated the mechanical properties of composite materials beam to using in numerical work. After this, is evaluating the natural frequency of hyper composite beam by numerical technique, and then, the results has been compared with the experimental results. Where, the comparison of the results has submit a good matching between the results of natural frequency experimentally and numerically with a maximum error of about (10.2%). Finally, the results of natural frequency beam are shown that the powder reinforcement is increase the strength of composite materials, then, the beam frequency was increased with increasing the volume fraction of the reinforcement powder.

10. An investigation study using mixture proportion of polyethylene glycol-water as quenching medium and their effects on low carbon steel heat treatment process

Ali Wafaa Aldeen Baqer

Materials department, University of Kufa, Iraq.

Abstract: Low carbon steels wide range using materials, chemical composition and physical properties controls by using heat treatment process that including heating and then cool by appropriate quenching mediums. The effects of polyethylene glycol diluted with water as quenching medium on the mechanical properties (hardness, compression) and microstructural properties of low carbon steel were investigated with the aim at improving their compatibility with polymer quenching. The tested samples were prepared and subjected to heat treatment process used electrical resistance furnace soaked for 1 hour and then quenched in polyethylene (PE) diluted with water in controlled percentages of PE% (25%, 35%,45%). Used digital microhardness and universal test machine resulted an enhancement in their mechanical properties, they though (PE) gives good cool rates. The dominant of martensitic phase in microstructures resulting in their enhancement of low carbon steel properties. The hardness improvement about 83.5% as illustrated with this paper, also the compressive strength improved about 23.3% with this work. Also, an enhancement of surface cracks was observed with increasing (PE) percentage. It is assumed that polyethylene solution will help to develop high performance of low carbon steel properties for industrial fields applications.