Gazi University Journal of Science Part A: Engineering and Innovation最新文献

{"title":"Numerical Analysis of the Effects of Fuel Injection Duration and Spray Angle on the Combustion Process in a Compression Ignition Engine","authors":"Fethi Balaban, Serdar Halis, H. S. Yücesu","doi":"10.54287/gujsa.1402652","DOIUrl":"https://doi.org/10.54287/gujsa.1402652","url":null,"abstract":"The changes in injection strategies for diesel engines have a major impact on the performance and pollutant emission characteristics of diesel engines. If injection strategies like injection duration, injection timing, injection pressure and spray angle are properly adjusted, combustion can be improved. The engine performance will increase and emissions will decrease with the combustion improvement. In this work, the influences of injection duration and spray angle on the combustion characteristics of single cylinder, natural aspirated, electronically controlled injection, compression ignition engine were investigated. In the first stage of the work, experiments were executed on a single cylinder CI engine using a Cussons P8160 DC dynamometer. After the experiments, the piston bowl geometry of the engine was modeled and numerical simulation studies were achieved at 7 different injection durations and 7 different spray angles using Converge CFD software. As a result of this study, it was observed that there is a good match between experimental and simulation data of heat release rate (HRR) and in-cylinder pressure. In-cylinder pressure decreased with longer injection duration. The highest max. in-cylinder pressure was roughly 101.0 bar at 4°CA injection duration and the lowest max. in-cylinder pressure was roughly 82.0 bar at 10°CA injection duration. When the HRR data were analyzed, it was seen that as the injection duration increased, the amount of heat released by combustion decreased. When examining the results of the spray angle analysis, it was concluded that there were not very large differences in-cylinder pressure and HRR data, and there was a difference of 1.4 bar between the highest and lowest max. in-cylinder pressure values. In addition, the highest in-cylinder pressure of approximately 86.7 bar was obtained at a spray angle of 77°. It was observed that the CA50 value was obtained at angles closer to the top dead center by increasing the spray angle and decreasing the injection duration. Moreover, the longest combustion durations were realized at 60° spray angle and 10°CA injection duration.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139687002","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 new and efficient pan sharpening method based on optimized pixel coefficients","authors":"Tuba Çağlikantar, Melih Can Kiliç","doi":"10.54287/gujsa.1407864","DOIUrl":"https://doi.org/10.54287/gujsa.1407864","url":null,"abstract":"Pan sharpening aims to create a multispectral, high spatial resolution image by combining the \u0000multispectral image (MSI) with a high spatial resolution panchromatic image (PAN). Pan \u0000sharpening methods are performed between the MS image, which is the MSI image brought to \u0000PAN dimensions with the help of interpolation, and the PAN image. In this study, PAN \u0000sharpening is approached as an optimization problem. It is assumed that the optimal solution \u0000consists of multiplying the pixels of the MS image by optimized coefficients. It would be costly \u0000to optimize all the coefficients in this coefficient matrix one by one. For this reason, these \u0000coefficients were tried to be found with 5 different optimization-based methods. It was also \u0000compared with 19 different methods commonly used in the literature. 6 different evaluation \u0000criteria were used for this comparison. These comparisons were made on 3 different datasets. It \u0000has been observed that the proposed methods are superior to other methods.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"624 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140483035","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":"Vücut Ağırlığını Tahmin Etmek İçin Kalça Ölçümlerinden Yararlanma: Ergonomik Tasarım için Kalça Genişliğini ve Popliteal Uzunluğu Keşfetmek","authors":"Adekunle Ibrahim Musa","doi":"10.54287/gujsa.1394955","DOIUrl":"https://doi.org/10.54287/gujsa.1394955","url":null,"abstract":"This study investigates the potential of utilizing buttock measurements, specifically buttock width and bottom popliteal length, as reliable indicators for estimating human body weight. Recognizing the increasing demand for accurate and accessible methods in various fields, author delves into the relationships between these lower body dimensions and overall body mass. The research evaluated 700 young adults, evenly split between 350 males and 350 females, utilizing random snowball sampling techniques from four local governments (Abeokuta South, Abeokuta North, Odeda and Ewekoro) areas of Ogun State, Southwestern Nigeria with participants aged between 19 and 27years The research centered on assessing human body weight (HBW), buttock width (BW), and bottom popliteal length (BPL) with all measurements documented in centimeters. Data analysis involved utilizing Statistical Package for Social Sciences 21.0, for computation of average mean values, standard deviation, coefficient of determination (R2), correlation coefficient (R), and standard error of estimates (SEE). Additionally, linear regression analysis was employed to formulate the model equation for determining HBW, in relation to BW, and BPL. The study provides an accuracy and applicability of anthropometric prediction of HBW and foundation for the development of practical methods with diverse applications, ranging from healthcare assessments to ergonomic design.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"38 3-4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140498590","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":"Impedance Response and Phase Angle Determination of Metal-Semiconductor Structure with N-Doped Diamond Like Carbon Interlayer","authors":"Nuray Urgun, Aylar Feizollahi Vahi̇d, J. Alsmael, B. Avar, S. O. Tan","doi":"10.54287/gujsa.1393292","DOIUrl":"https://doi.org/10.54287/gujsa.1393292","url":null,"abstract":"Schottky Barrier Diodes have been studied largely in literature for their superior properties over p-n barriers in a wide range of components like solar cells, sensors, gate stacks of FETs, back-end-switch arrays, and super capacitor applications basically as a test tool to produce better performance devices. The main performance parameter of these devices is measured by their conduction mechanisms under desired conditions like temperature, pressure, voltage, frequency and radiation. And one of the pivotal enhancements on device performance is provided by interlayer addition through the sandwich design. And presence of these interlayers with on-purpose impurities, develops even more control of conduction mechanisms over semiconducting and metal layers. As an adjustable host material for impurity atoms, DLC, which also has outstanding specifications under thermal, chemical and physical conditions, is a good candidate for interlayer tailoring specifically when used with doping atoms like nitrogen (N), copper (Cu), gold (Au), titanium (Ti) and silicone (Si). This study investigates the impedance response of the fabricated device with an N-doped DLC interlayer. The results revealed that the reminiscent matrixial distribution of charges should be affecting the conduction path through horizontal and vertical dielectric relaxation appearance with altering relative permittivity due to different bond formations between different phases of the same material in the insulating layer. The supported results by phase angle changes, showing frequency-adjustable working conditions offer that the selective electrical conduction can be tuned.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140503131","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":"Boron-doped thin films fabricated by the spin coating method: the effect of doping concentrations","authors":"A. Atilgan, Kenan Özel","doi":"10.54287/gujsa.1362103","DOIUrl":"https://doi.org/10.54287/gujsa.1362103","url":null,"abstract":"This work examined the impact of different levels of B-doping on the structural, morphological, optical, and electrical characteristics of ZnO thin films. Boron-doped zinc oxide thin films were deposited on glass substrates using the spin-coating technique. The B concentrations employed were 1, 2, 3, 4, and 5 at. %. The systematic characterizations manifest that the properties of the deposited films were heavily influenced by changing concentrations of B doping. It was found that as the concentration of B-doping increases, the values of grain size decrease. In addition, it was observed that ZnO thin films containing a lower concentration of B dopant exhibited higher transparency. Finally, it was figured out that the resistivity of the films declines dramatically with a higher content of B-doping. The results of our research may initiate further inquiries into the creation of superior thin films.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"265 1‐5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139152852","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":"Kantorovich Stancu Type Operator Including Generalized Brenke Polynomials","authors":"Gürhan Içöz, Shamsullah Zaland","doi":"10.54287/gujsa.1386488","DOIUrl":"https://doi.org/10.54287/gujsa.1386488","url":null,"abstract":"This article is concerned with the sequence of operators of Stancu’s-type, involving extended Brenke polynomials. We apply Korovkin’s theorem to the sequence of positive linear operators, discuss the uniform approximation of continuous functions on closed bounded intervals by known tools theory, and also consider the second modulus of continuity, Peetre’s K-functional and Lipschitz class, which are essential concepts in approximation theory.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"72 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139153188","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 Turkey’s Climate for Service Lifetime of Photovoltaic Modules: A Mapping Approach","authors":"Abdülkerim Gök","doi":"10.54287/gujsa.1357247","DOIUrl":"https://doi.org/10.54287/gujsa.1357247","url":null,"abstract":"The longevity of photovoltaic systems during real-world operation is a concern that needs to be addressed. Polymeric materials used in module constructions, particularly encapsulants, are susceptible to hydrolysis, which can lead to cell metallization corrosion and result in power loss and shortened service lifetime. One of the test protocols within the current certification standard of IEC 61215 is damp heat exposure, which subjects the modules to constant temperature and humidity level for a specific duration (85°C/85%RH for 1000 hours). However, its effectiveness as a reliability test for long-term durability is often debated. This study applies a methodology for calculating the equivalent damp heat testing time that corresponds to a targeted service lifetime (i.e., 30 years) in real-world conditions. The results are presented in the form of a country map, focusing on Turkey, illustrating the variations in testing times across different regions due to local climate conditions. This study shows that applying a single set of conditions for a fixed duration, as applied in the damp heat testing, to all modules with different components and for all climate conditions poses substantial risks when it comes to predicting service lifetime.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"1 1‐2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139156978","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":"Enhancing Software Process Assessment with an Ontology-Based Tool: Integrating CMMI, SPICE, and TMMI Models","authors":"Rukiye Başkara, Ahmet Coşkunçay","doi":"10.54287/gujsa.1384048","DOIUrl":"https://doi.org/10.54287/gujsa.1384048","url":null,"abstract":"Software process reference models like CMMI and SPICE have played a crucial role in evaluating processes for several decades. Their adoption by institutions has become essential for consistently delivering software projects to customers on time and with expected quality. However, conducting software process assessments demands considerable time, effort, and skilled personnel. This research introduces an ontology-based tool that facilitates software process assessment for organizations by integrating widely-used process reference models, namely CMMI, SPICE, and TMMI. The development of this tool involves multiple stages: creating ontologies for each process reference model, integrating them into the tool, enabling querying capabilities, and visualizing the ontologies. Through a validation study in a selected organization, two sets of processes were assessed using the Ontology-Based Software Process Assessment Tool (OSPAT). The results demonstrated that organizations can benefit from OSPAT in evaluating their software development processes across diverse reference models, thereby enhancing overall process efficiency and quality.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"57 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139157317","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 Analysis of Optimal Control Strategies: LQR, PID, and Sliding Mode Control for DC Motor Position Performance","authors":"Hakan Kızmaz","doi":"10.54287/gujsa.1393092","DOIUrl":"https://doi.org/10.54287/gujsa.1393092","url":null,"abstract":"This study applies these control methods to the DC motor system to examine the robustness and performance of four optimal control methods. Optimal controllers aim to control the system to minimize a selected performance index. These control methods offer advantages such as improving energy efficiency, reducing costs, and enhancing system security. The Linear Quadratic Regulator (LQR) based controller is the primary optimal control method. Two well-known traditional control techniques include the Proportional-Integral-Derivative (PID) and Integral Sliding Mode Controller (ISMC). However, they do not usually contain optimal properties. In this study, the optimal control algorithms, defined by obtaining controller parameters through the Riccati equation, are applied to achieve accurate position-tracking control in a DC motor system using Matlab/Simulink. The integral term-based algorithms seem to be robust and eliminate steady-state errors. The optimal PID controller could not provide the minimum performance index rather than the others. LQR and optimal ISMC algorithms could allow the performance index to be a minimum. An illustrative comparison of the performances of all optimal control algorithms has been presented through graphical representation, along with corresponding interpretations.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"39 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139157247","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":"An Informetric View to the Negative Capacitance Phenomenon at Interlayered Metal-Semiconductor Structures and Distinct Electronic Devices","authors":"Nuray Urgun, Jaafar Alsmael, S. O. Tan","doi":"10.54287/gujsa.1357391","DOIUrl":"https://doi.org/10.54287/gujsa.1357391","url":null,"abstract":"Negative Capacitance (NC) phenomenon, which can be explained as the material exhibiting an inductive behavior, is often referred to as \"anomalous\" or \"abnormal\" in the literature. Especially in the forward bias/deposition region, the presence of surface states (Nss) and their relaxation times (τ), series resistance (Rs), minority carrier injection, interface charge loss in occupied states under the Fermi energy level, parasitic inductance, or poor measuring equipment calibration problems can be counted among the causes of this phenomenon. Studies on NC behavior have shown that this behavior can be observed for different frequencies, temperatures, and related parameters at forward biases. However, the NC behavior, which appears as an unidentified peak in admittance spectroscopy data, is not yet fully understood. Ultimately, this study aims to compile and analyze the NC reported in selected scientific studies, investigate the source of this phenomenon, and observe statistics in a general view.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"70 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139003611","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}