European Mechanical Science最新文献

{"title":"Fibre Volume Fraction and Impact Strength Analysis of Reinforced Polyester Composites","authors":"D. D. Olodu, Osagie Ihenyen","doi":"10.26701/EMS.850970","DOIUrl":"https://doi.org/10.26701/EMS.850970","url":null,"abstract":"Improper fibre volume analyses in most reinforced composites poses great challenges in polymer industries which results to the production of composites with low mechanical strength. This study investigates the fibre volume fraction and impact strength analysis of reinforced polyester composites. In this study, E-Glass fibres (hard and soft mat) were mixed with polyester at different composition by volume. The E-glass serves as reinforcement to the polyester, fourteen test specimens of the reinforced composites were developed with each of them having dimension of 210mm length, 150mm width and 50mm thickness respectively. The properties of the developed reinforced composites such as volume fraction, impact energy, and impact strength were analysed from the values obtained from compact tension and Charpy impact test respectively. The results obtained shows that the effective thickness of the developed reinforced composites ranged from 60mm to 100mm at fibre fraction which ranges from 0.32 to 0.50. The results obtained also shows that the specimens containing woven roving have greater resistance to fracture and impact damages due to high fibre volume fraction. Hence, the laminates impact strength is a function of its fibre volume fraction.","PeriodicalId":373904,"journal":{"name":"European Mechanical Science","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121522469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Building Up Mathematical Modeling Using Spot Welding Parameters and Prediction Weld Nugget by Minitab","authors":"I. Cekić, K. Çavdar","doi":"10.26701/EMS.837829","DOIUrl":"https://doi.org/10.26701/EMS.837829","url":null,"abstract":"In serial production, problems are constantly encountered in the selection of welding parameters due to the excess of welding parameters and variations. In order to compensate for these variations, mostly high energy flux is used. In this study, an approach developed in order to estimate weld nugget diameter in determining the welding parameters for sheets with a thickness of 0.6-3 mm is introduced. Minitab statistical program was used to create experimental data and mathematical operations. First of all, 7 source parameters were selected and experimental design (DOE) was carried out for 64 experiments using the ½ partition factorial method in Minitab software. With the experiments, real weld nugget diameters were obtained. These results were transferred to the Minitab software and the mathematical model of the system was established. Weld nugget diameter estimation procedures were carried out using the experimental design (DOE) data. Test and prediction data were transferred to Minitab software, regression graph was drawn and R-Sq and R-Sq (adj) values were calculated. In addition, samples were created with randomly selected data for verification and comparison was made by transferring them to Minitab. According to the results of this study, remarkable accuracy rates have been achieved in the weld nugget diameter estimation with Minitab.","PeriodicalId":373904,"journal":{"name":"European Mechanical Science","volume":"143 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131758005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance Analysis of a Large-Scale Steam Condenser Used in a Steam Power Plant","authors":"Mehmet Tontu","doi":"10.26701/ems.644733","DOIUrl":"https://doi.org/10.26701/ems.644733","url":null,"abstract":"This paper summarizes performance analysis of large-scale seawater-cooled box type condenser in a 660 MW steam power plant. Effect of seawater temperature and steam mass flow rate are investigated on the key performance parameters of steam condenser. Results indicated that improvement in the cooling water temperature generally is found favorable on the performance indicators of condenser. On the other hand, in the case of steam flow rate changing, effectiveness and overall heat transfer coefficient almost remain constant. Effectiveness of condenser isn’t found as a function of steam flow variation. Moreover, steam power plant heat rate is investigated as a function of cooling water of condenser and thus it is seen to be decreased in the result of improvement of cooling water temperature. Conversely, power plant overall thermal efficiency decreases due to reduction of power generation.","PeriodicalId":373904,"journal":{"name":"European Mechanical Science","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131082118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The dispersion energy parameters, Linear and nonlinear optical properties of Transparent Mn:ZnO nanolayers","authors":"C. Aydın","doi":"10.26701/ems.710165","DOIUrl":"https://doi.org/10.26701/ems.710165","url":null,"abstract":"Throughout this research, the impact of Manganese doping on the optical characteristics of ZnO nanolayers was explained. The sol-gel spin coating technique has significant advantages due to the mixing of components on the atomic scale and provides excellent control over the composition that was employed to produce samples. The optical characteristics of Mn: ZnO nanolayers, were determined with the help of UV-VIS-NIR spectroscopy. The linear and nonlinear optical properties of nanolayers were investigated between 300 and 800 nm wavelengths. The dispersion properties of the samples were determined and interpreted in accordance with the single-oscillator model. The third-order nonlinear optical characteristics indicate a good correlation between theoretical and experimental results. These interesting results obtained by Mn-doping of ZnO showed a significant behavior for technological applications in electronic, optoelectronic devices and nonlinear optical applications.","PeriodicalId":373904,"journal":{"name":"European Mechanical Science","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127737603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Numerical Investigation of The Fracture Energy of Materials for Fuel Cell End Plates","authors":"Adem Avcu, N. Choupani, G. Tüccar","doi":"10.26701/EMS.792302","DOIUrl":"https://doi.org/10.26701/EMS.792302","url":null,"abstract":"Nowadays, with increasing energy requirements, the use of clean energy resources has become important. Fuel cells are an important key for clean energy technology due to wide range of utilization areas such as automotive, portable power applications, electricity generation, space, aviation and naval technologies. Additionally, they have many significant properties such as not producing harmful gases, therefore they do not cause environmental and chemical pollution. Besides, they have not any moving parts, also they do not produce noise. By comparison to fossil fuel, fuel cells have high efficiency that reaches up to 60% in appropriate conditions. Proton Exchange Membrane Fuel Cell (PEMFC) has many advantages than other fuel cell types due to simple structure, higher efficiency and low operating temperature. PEMFC may consist of one or more stacks to generate more electricity. End plate of PEMFC holds together all parts of it. Therefore, the material selection for end plate is important to provide safe conditions. To use PEMFC safely, investigation of material fracture energy is required to decide that the material is in safe conditions or not. There are three fracture energy modes which are mode I, mode II and mode III. There are many methods to investigate failure of material at different modes. Unlike other methods, Arcan specimen gives facility to evaluate of mode I, mode II and mixed modes. The main purpose of this paper was to compare the results of fracture energy (stain energy release rate) of different materials for end plates in fuel cells. Another goal was to select a suitable material was selected as PEMFC end plate.","PeriodicalId":373904,"journal":{"name":"European Mechanical Science","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117161214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of the Effects of Gasoline-Bioethanol Blends on Engine Performance and Exhaust Emissions in a Spark Ignition Engine","authors":"S. Yelbey, M. Ciniviz","doi":"10.26701/ems.635790","DOIUrl":"https://doi.org/10.26701/ems.635790","url":null,"abstract":"In this study; 95 octane unleaded gasoline and bioethanol were tested as fuel in a spark-ignition engine by blending bioethanol with gasoline in certain proportions (2%, 4%, 6%, 8%, 10%). Tests were carried out at five different engine loads for a constant engine speed of 2500 rpm. The variations in engine performance parameters (brake thermal efficiency, brake specific fuel consumption, brake specific energy consumption) and exhaust emissions (HC, CO, CO 2 and O 2 ) were investigated on the basis of test fuel and engine load. According to the test results, with the increase of bioethanol ratio in the blend, brake specific fuel consumption values ​​increased by 9.71% and brake thermal efficiency values ​​decreased by approximately 4.97% compared to gasoline. There was decrease in HC and CO emissions and an increase in CO 2 emissions with bioethanol addition.","PeriodicalId":373904,"journal":{"name":"European Mechanical Science","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127820597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spark Plasma Sintering of Nano Silicon Carbide Reinforced Alumina Ceramic Composites","authors":"M. Gök","doi":"10.26701/EMS.841961","DOIUrl":"https://doi.org/10.26701/EMS.841961","url":null,"abstract":"At this point, it is reported that the amount, size, morphology and distribution of SiC phase added into the alumina matrix has a great effect on the mechanical properties of Al 2 O 3 [11]. Razavi et al. [10] produced the Al 2 O 3 -SiC composite ceramics by using spark plasma sintering (SPS) method at temperatures of 1600 °C for 10 min holding time and they measured the hardness and fracture toughness values of the monolithic Al 2 O 3 as 1387 Hv and 250.4 MPa, respectively. Researchers showed that hardness of the composite containing 20 wt. % Abstract Although Al 2 O 3 has been commercially preferred material, it cannot be used in applications subject to variable and sudden loads due to its low fracture toughness. In this study, as the primary purpose, nano-SiC particles were used as reinforcement phase to improve the fracture toughness of the Al 2 O 3 ceramic. Ultrasonic dispersion was used to ensure good dispersion of the nano reinforcement phase in the matrix. Production was carried out by spark plasma sintering method at temperatures of 1325 °C for 5 min under 40 MPa pressure and vacuum atmosphere. Densification behavior, density, microstructure, phase analysis, hardness and fracture toughness of the sintered Al 2 O 3 /nano-SiC composites were investigated. The highest hardness and fracture toughness of 22.83 GPa and 6.09 MPa·m 1/2 were achieved, respectively.","PeriodicalId":373904,"journal":{"name":"European Mechanical Science","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121972488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal Comfort in an Office Room Using Square Diffuser","authors":"A. Yıldırım, C. Ozalp","doi":"10.26701/EMS.886027","DOIUrl":"https://doi.org/10.26701/EMS.886027","url":null,"abstract":"velocity distribution and air flow patterns. Abstract The office is an important part of daily life, people spend most of their time working inside of the office and thus the quality of the indoor air environment is a significant factor affecting the productivity and happiness of office users. Many factors influence the pattern of airflow: indoor air quality, thermal comfort and energy saving in an office room. In this study, the effects of the square diffusers on thermal comfort investigated numerically for an office room. Numerical research was subsequently carried out using the validated CFD (computational fluid dynamics) model. This model solved the continuity, energy conservation and momentum equations in addition to k–ε model equation for turbulence modelling. Predicted Percentage of Dissatisfied (PPD) is a frequently used tool for assessing human comfort rating. A PPD based control HVAC (Heating, Ventilating and Air Conditioning) system has the potential to provide enhanced thermal comfort inside a location by taking into consideration all main thermal comfort variables. The CFD results revealed that the PPD values in the room varies on average between 10% and 20% and thus thermal conditions occurred according to ASHRAE standards in the model office room with a square diffuser.","PeriodicalId":373904,"journal":{"name":"European Mechanical Science","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126219189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Static Analysis of FG Beams via Complementary Functions Method","authors":"A. Noori, Timuçin Alp Aslan, Beytullah Temel","doi":"10.26701/EMS.590864","DOIUrl":"https://doi.org/10.26701/EMS.590864","url":null,"abstract":"Static analysis of Functionally Graded (FG) beams is studied by the Complementary Functions Method (CFM). The material properties, Young’s modulus, of the straight beams, are graded in the thickness direction based on a power law distribution while the Poisson’s ratio is supposed to be constant. Governing equations of the considered problem are obtained with the aid of minimum total potential energy principle based on Timoshenko’s beam theory (FSDT). The main purpose of this paper is the infusion of the CFM to the static analysis of FG straight beams. The effectiveness and accuracy of the proposed method are confirmed by comparing its numerical results with those available in the literature. Application of this efficient method provides accurate results of static response for FGM beams with different variations of material properties in the thickness of the beam.","PeriodicalId":373904,"journal":{"name":"European Mechanical Science","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121555004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative Techno-Economic Study of Solar Thermal Power Plants with Various Capacities: A Case for the Northern Part of Cameroon","authors":"Biboum Alain Christian, A. Yilanci","doi":"10.26701/EMS.493214","DOIUrl":"https://doi.org/10.26701/EMS.493214","url":null,"abstract":"The purpose of this article is to evaluate the commercial use of different solar thermal power technologies in the northern part of Cameroon. For this, a techno-economic study highlighting the design of each technology using various capacities of the studied plant. The main objective was to carry out, technical, economic and financial parameters able to attract investors for the use of such kinds of technology to generate electricity in these provinces [G1] having a good direct normal irradiation estimated at 2145kWh/m 2 /year and meet at the energy demand of population living with less than 10% electrification rate in rural area. During this study, we considered some technical paramet [G2] ers as total annual DNI received by solar field, Field thermal output, thermal system transfer rated, overall energy efficiency and yearly electricity production. The last parameter was a key parameter for techno-economic analysis of the studied system. [G3] Some parameters as the payback period (PBP), internal rated return (IRR), net present value (NPV) and levelized cost of electricity (LCOE) have been found out during the economic analysis. The bonus carbon can be allowed to a company because of the good electricity generation has been applied during the calculation of these parameters. Other parameters as the initial investment and incentives from the government or financial named in this study have been considered also. The [G4] environmental and social impact assessment (ESIA) related to this purpose give a priority to criteria as grid, land and water access and use for electricity generating. Then, the ESIA study has been considered as a key parameter for Multi-Criteria Decision Maker. The studied systems  had various range capacity  starting from 5 MW to 100 MW  and their analysis in the sub-Saharan region [G5] shown that, the cost of installed kW for concentrating solar technologies (CST) varies between 4550 – 6745 US Dollar   ,  5240 – 9365 US Dollar   and 5100 - 6290 US Dollar   and the levelized cost of electricity per kWh varies between 10.22-13.22 USD cents, 11.07-19.81 USD cents and 14.63-15.6 USD cents for Parabolic trough collector(PTC), Solar Tower (ST) and Linear Fresnel (LF) respectively. The solar tower technology can't be efficient compared to other techniques for the thermal power plant (TPP) under 10 MW [G6] [G7] [G8] e due to the initial investment. It important to add this, the cost of installed kW in the sub-Saharan region is higher [G9] than order region because of transportation fees, the lake of solar thermal manufactures for insulation and piping system, metal structure and expertise related to total indirect cost such as engineering procurement construction and advanced ESIA services in this area.  The support of financial institution through CER/TAX and a similar approach in addition to existing subvention [G10] [G11] s for such technology can decrease considerably both payback period and feed-in-tariff (FIT) price of the studi","PeriodicalId":373904,"journal":{"name":"European Mechanical Science","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125131213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}