Large-scale systems have a lower levelized cost of electricity than small-scale concentrated solar power systems. Thus, the purpose of the present study is to evaluate the potential of using standalone small-scale concentrated solar power collectors in order to generate process heat at a moderate temperature, which directly utilizes thermal energy without the need to generate electricity. A parabolic trough collector (3.6m2) was designed and manufactured, including a dual-axis solar tracking system with and without an insulating function. An insulating cavity was incorporated to minimize the heat losses collected by the absorbed tube. The experiments were carried out during a time of high winds and unfavorable weather in Sabratha City. The findings of the experiments demonstrated that the produced temperature and the collected heat energy progressively increase until they reach their maximum value, and then gradually decrease. The maximum water temperature was 96ºC at a flow rate of 0.5L/min, and the highest amount of heat energy was 550W/m². Wind speed showed an important impact on the produced temperature; therefore, various comparative experiments were carried out in the same climate condition; the experiment with the insulating function presented the least heat loss, and it takes a higher edge of 11% in terms of efficiency. In addition, the water temperature rose to 120°C where steam was generated at a zero flow rate, while the oil reached 194ºC. In addition, a mathematical model was also implemented to theoretically study energy balance; with little expected discrepancy, its predictions and the experimental results agreed. In conclusion, the results presented reasonable markers of interest despite the poor environmental conditions during the experiments.
{"title":"Experimental Investigation of a Small-Scale Parabolic Trough Concentrated Solar Power Systems","authors":"Ismael A. S. Ehtiwesh","doi":"10.35378/gujs.1311796","DOIUrl":"https://doi.org/10.35378/gujs.1311796","url":null,"abstract":"Large-scale systems have a lower levelized cost of electricity than small-scale concentrated solar power systems. Thus, the purpose of the present study is to evaluate the potential of using standalone small-scale concentrated solar power collectors in order to generate process heat at a moderate temperature, which directly utilizes thermal energy without the need to generate electricity. A parabolic trough collector (3.6m2) was designed and manufactured, including a dual-axis solar tracking system with and without an insulating function. An insulating cavity was incorporated to minimize the heat losses collected by the absorbed tube. The experiments were carried out during a time of high winds and unfavorable weather in Sabratha City. The findings of the experiments demonstrated that the produced temperature and the collected heat energy progressively increase until they reach their maximum value, and then gradually decrease. The maximum water temperature was 96ºC at a flow rate of 0.5L/min, and the highest amount of heat energy was 550W/m². Wind speed showed an important impact on the produced temperature; therefore, various comparative experiments were carried out in the same climate condition; the experiment with the insulating function presented the least heat loss, and it takes a higher edge of 11% in terms of efficiency. In addition, the water temperature rose to 120°C where steam was generated at a zero flow rate, while the oil reached 194ºC. In addition, a mathematical model was also implemented to theoretically study energy balance; with little expected discrepancy, its predictions and the experimental results agreed. In conclusion, the results presented reasonable markers of interest despite the poor environmental conditions during the experiments.","PeriodicalId":12615,"journal":{"name":"gazi university journal of science","volume":"5 1-3","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139280434","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}
After the settlement textures were designed and constructed, they continue to exist without any change for years, and they have considerable effects on building energy consumptions and the natural environment. In addition, with the changes in our lives through the COVİD-19 pandemic, the houses have turned into versatile spaces where we spend most of the time and the amount of energy used in the houses has increased even more. The decrease of energy usage is a top objective in the design of the settlements from an economic and environmental standpoint. Therefore, the design parameters affecting the energy consumptions in the settlement textures are evaluated with a holistic approach, both settlement scale and building scale. The study is focused to determine appropriate values for the design parameters. In addition, energy modelling and simulations were carried out with BIM software, and the use, advantages and capabilities of BIM systems were tested in the energy efficient design for reducing energy consumptions. As a result, energy consumption in buildings get changes greatly in regard to settlement scale and building scale design parameters. Selecting the proper values for design parameters affects the building's energy performance and helps create sustainable and energy-efficient environment.
{"title":"EVALUATION OF BUILDING ENERGY PERFORMANCE BASED ON SETTLEMENT SCALE DESIGN PARAMETERS USING BIM TOOLS","authors":"Mehmet Akif Aydin, Gül Koçlar Oral","doi":"10.35378/gujs.1277880","DOIUrl":"https://doi.org/10.35378/gujs.1277880","url":null,"abstract":"After the settlement textures were designed and constructed, they continue to exist without any change for years, and they have considerable effects on building energy consumptions and the natural environment. In addition, with the changes in our lives through the COVİD-19 pandemic, the houses have turned into versatile spaces where we spend most of the time and the amount of energy used in the houses has increased even more. The decrease of energy usage is a top objective in the design of the settlements from an economic and environmental standpoint. Therefore, the design parameters affecting the energy consumptions in the settlement textures are evaluated with a holistic approach, both settlement scale and building scale. The study is focused to determine appropriate values for the design parameters. In addition, energy modelling and simulations were carried out with BIM software, and the use, advantages and capabilities of BIM systems were tested in the energy efficient design for reducing energy consumptions. As a result, energy consumption in buildings get changes greatly in regard to settlement scale and building scale design parameters. Selecting the proper values for design parameters affects the building's energy performance and helps create sustainable and energy-efficient environment.","PeriodicalId":12615,"journal":{"name":"gazi university journal of science","volume":"1 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139283082","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}
Main results: The system of Christoffel symbols of the connection of an immersion ξ:J→R^n of an n-dimensional manifold J in the n-dimensional linear space R^n is a system of generators of the differential field of all Aff(n)-invariant differential rational functions of ξ, where Aff(n) is the group of all affine transformations of R^n. A similar result have obtained for the subgroup SAff(n) of Aff(n) generated by all unimodular linear transformations and parallel translations of R^n. Rigidity and uniqueness theorems for immersions ξ:J→R^n in geometries of groups Aff(n) and SAff(n) were obtained. These theorems are given in terms of the affine connection and the volume form of immersions.
{"title":"Invariants of Immersions on n-Dimensional Affine Manifold","authors":"D. Khadjiev, Gayrat Beshi̇mov, İdris Ören","doi":"10.35378/gujs.1037048","DOIUrl":"https://doi.org/10.35378/gujs.1037048","url":null,"abstract":"Main results: The system of Christoffel symbols of the connection of an immersion ξ:J→R^n of an n-dimensional manifold J in the n-dimensional linear space R^n is a system of generators of the differential field of all Aff(n)-invariant differential rational functions of ξ, where Aff(n) is the group of all affine transformations of R^n. A similar result have obtained for the subgroup SAff(n) of Aff(n) generated by all unimodular linear transformations and parallel translations of R^n. Rigidity and uniqueness theorems for immersions ξ:J→R^n in geometries of groups Aff(n) and SAff(n) were obtained. These theorems are given in terms of the affine connection and the volume form of immersions.","PeriodicalId":12615,"journal":{"name":"gazi university journal of science","volume":"31 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139290080","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}
Power electronic systems are rapidly evolving; thus, effective prototyping methods are required to test control algorithms and assess system performance prior to hardware implementation. This research suggests a Model-In-The-Loop (MIL), Software-In-The-Loop (SIL), and Processor-In-The-Loop (PIL) methodologies-based complete prototyping strategy for flyback converters using the TI F28069M Launchpad kit. These techniques can be combined to evaluate control strategies accurately and quickly, speeding up design cycles and enhancing system reliability. The proposed prototyping platform is presented in this work, along with a thorough explanation of each prototyping stage and its associated advantages. The effectiveness of the suggested approach for 50W rated power flyback converter in terms of quick algorithm development, system simulation, real-time control implementation and controller design accuracy is analyzed and shown by experimental results. The results show that the performance of the designed controller for the flyback converter is almost the same as in MIL and SIL implementation in terms of the overshoot and settling time in the reference voltage tracking. On the other hand, in the PIL implementation, the overshoot performance of the controller deviates by 1.18% more than in SIL and MIL implementation. These also confirm that the flyback control system's performance is reliable and effective during all phases of development.
电力电子系统发展迅速，因此需要有效的原型开发方法，以便在硬件实施之前测试控制算法和评估系统性能。本研究提出了一种基于模型在环 (MIL)、软件在环 (SIL) 和处理器在环 (PIL) 方法的完整原型开发策略，适用于使用 TI F28069M Launchpad 套件的反激式转换器。这些技术可结合使用，以准确快速地评估控制策略，从而加快设计周期并提高系统可靠性。本作品介绍了所建议的原型验证平台，并对每个原型验证阶段及其相关优势进行了详细说明。实验结果分析并显示了针对 50W 额定功率反激式转换器所建议的方法在快速算法开发、系统仿真、实时控制实现和控制器设计精度方面的有效性。结果表明，反激式转换器的设计控制器在参考电压跟踪的过冲和沉淀时间方面的性能与 MIL 和 SIL 实现几乎相同。另一方面，在 PIL 实现中，控制器的过冲性能比 SIL 和 MIL 实现多偏差 1.18%。这也证实了反激式控制系统在所有开发阶段的性能都是可靠和有效的。
{"title":"MIL, SIL and PIL Implementation for Closed Loop Control of Flyback Converter","authors":"Muhammad Ali, İsmet Şen, Saliha Öztürk, Emre Avci","doi":"10.35378/gujs.1342626","DOIUrl":"https://doi.org/10.35378/gujs.1342626","url":null,"abstract":"Power electronic systems are rapidly evolving; thus, effective prototyping methods are required to test control algorithms and assess system performance prior to hardware implementation. This research suggests a Model-In-The-Loop (MIL), Software-In-The-Loop (SIL), and Processor-In-The-Loop (PIL) methodologies-based complete prototyping strategy for flyback converters using the TI F28069M Launchpad kit. These techniques can be combined to evaluate control strategies accurately and quickly, speeding up design cycles and enhancing system reliability. The proposed prototyping platform is presented in this work, along with a thorough explanation of each prototyping stage and its associated advantages. The effectiveness of the suggested approach for 50W rated power flyback converter in terms of quick algorithm development, system simulation, real-time control implementation and controller design accuracy is analyzed and shown by experimental results. The results show that the performance of the designed controller for the flyback converter is almost the same as in MIL and SIL implementation in terms of the overshoot and settling time in the reference voltage tracking. On the other hand, in the PIL implementation, the overshoot performance of the controller deviates by 1.18% more than in SIL and MIL implementation. These also confirm that the flyback control system's performance is reliable and effective during all phases of development.","PeriodicalId":12615,"journal":{"name":"gazi university journal of science","volume":"9 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139301462","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}
The literature in the field of Lean Six Sigma (LSS) is developing in Türkiye as well as over the world. However, theses and papers written in Turkish are waiting to be disseminated. This paper aims to investigate LSS in the Turkish context with the purpose of identifying the current state, gaining insight and exploring future directions. This paper implements the systematic literature review methodology to identify and review all relevant studies in Turkish literature. This paper covers the literature on LSS in Türkiye from 2004 to 2021. As a result, a total of 32 theses and 29 papers were investigated in detail. This paper not only focuses on years, sectors, areas etc. of the studies, but also analyses the contents of papers in relation to enterprise size, project prioritization, and quality tools used in DMAIC phases, and improvements after implementation in terms of descriptive and content analysis. The results show that, although there are many LSS implementations in Turkish context, they could not be shared with global academic area due to the national language usage. LSS implementations have an increasing trend in last years and highly focused on manufacturing sector and large companies. The lack of structured way of applying LSS, especially not using project prioritization and selection methodology takes attention. This paper shows the gaps and future directions in Türkiye for researchers and provides a groundwork to develop a roadmap for Turkish organizations.
{"title":"Lean Six Sigma Studies in Türkiye: A Literature Review","authors":"Nurcan Deniz, İlknur Tükenmez","doi":"10.35378/gujs.1176313","DOIUrl":"https://doi.org/10.35378/gujs.1176313","url":null,"abstract":"The literature in the field of Lean Six Sigma (LSS) is developing in Türkiye as well as over the world. However, theses and papers written in Turkish are waiting to be disseminated. This paper aims to investigate LSS in the Turkish context with the purpose of identifying the current state, gaining insight and exploring future directions. This paper implements the systematic literature review methodology to identify and review all relevant studies in Turkish literature. This paper covers the literature on LSS in Türkiye from 2004 to 2021. As a result, a total of 32 theses and 29 papers were investigated in detail. This paper not only focuses on years, sectors, areas etc. of the studies, but also analyses the contents of papers in relation to enterprise size, project prioritization, and quality tools used in DMAIC phases, and improvements after implementation in terms of descriptive and content analysis. The results show that, although there are many LSS implementations in Turkish context, they could not be shared with global academic area due to the national language usage. LSS implementations have an increasing trend in last years and highly focused on manufacturing sector and large companies. The lack of structured way of applying LSS, especially not using project prioritization and selection methodology takes attention. This paper shows the gaps and future directions in Türkiye for researchers and provides a groundwork to develop a roadmap for Turkish organizations.","PeriodicalId":12615,"journal":{"name":"gazi university journal of science","volume":"52 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139308405","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}
Muhammet Topuz, M. Keskin, Murat Karabulut, Nurgül KARLIOĞLU KILIÇ
Lake sediments offer valuable information about the geographical, climatic and environmental changes. This work examined the chemical elements of eleven sediment samples from the old bottom (0-5m; 0.5m increments) of the dried Lake Gavur in Türkiye by applying XRF along with PCA and PLSR data analyses. The highest but negative correlations were observed for Sr (-0.89), S+SO3 (-0.74) and Zr+ZrO2 (-0.61) with sampling depths meaning that their concentrations were lower in deeper locations (4.0-5.0 m). In contrast, Ti+TiO2 (0.60), Al+Al2O3 (0.53) and Cu+CuO (0.51) had high and positive correlations and their quantities increased as the depth increased. The age of two samples was determined as 4752±33 BP years (2.5 m) and 5470±35 BP (5.0 m). Ca+CaO content was found as lower and Ti+TiO was higher in the deeper sediment (5.0 m) indicating rainy periods. PCA clustered the samples into two groups as deeper samples (4.0-5.0 m) and other samples (0.0-3.5m) while PLSR grouped them into three clusters as deeper (4.0-5.0 m), medium-depth (1.5-3.5 m) and shallower (0.0-1.0m) samples. PLSR model had a good performance to estimate the sampling depth from the chemical elements (R2cal=0.95; R2val=0.67) which means that the variations of the chemicals were highly dependent on the sampling depth.
{"title":"An Investigation of the Chemical Composition of Bottom Sediments from Dried Lake Gavur of Türkiye by Using XRF and Multivariate Data Analysis","authors":"Muhammet Topuz, M. Keskin, Murat Karabulut, Nurgül KARLIOĞLU KILIÇ","doi":"10.35378/gujs.1240178","DOIUrl":"https://doi.org/10.35378/gujs.1240178","url":null,"abstract":"Lake sediments offer valuable information about the geographical, climatic and environmental changes. This work examined the chemical elements of eleven sediment samples from the old bottom (0-5m; 0.5m increments) of the dried Lake Gavur in Türkiye by applying XRF along with PCA and PLSR data analyses. The highest but negative correlations were observed for Sr (-0.89), S+SO3 (-0.74) and Zr+ZrO2 (-0.61) with sampling depths meaning that their concentrations were lower in deeper locations (4.0-5.0 m). In contrast, Ti+TiO2 (0.60), Al+Al2O3 (0.53) and Cu+CuO (0.51) had high and positive correlations and their quantities increased as the depth increased. The age of two samples was determined as 4752±33 BP years (2.5 m) and 5470±35 BP (5.0 m). Ca+CaO content was found as lower and Ti+TiO was higher in the deeper sediment (5.0 m) indicating rainy periods. PCA clustered the samples into two groups as deeper samples (4.0-5.0 m) and other samples (0.0-3.5m) while PLSR grouped them into three clusters as deeper (4.0-5.0 m), medium-depth (1.5-3.5 m) and shallower (0.0-1.0m) samples. PLSR model had a good performance to estimate the sampling depth from the chemical elements (R2cal=0.95; R2val=0.67) which means that the variations of the chemicals were highly dependent on the sampling depth.","PeriodicalId":12615,"journal":{"name":"gazi university journal of science","volume":"26 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139314943","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}
Adeola Ibi̇kunle, T. Osobami̇ro, Najeem Babari̇nde, Feyisara Adaramola
The batch adsorptive sequestration of methylene blue from an aqueous solution using unripe Roystonea regia fruit pericarp biomass was investigated in this study. The characteristic nature of the biosorbent was studied using various analytical instruments including Fourier Transform Infra-red spectrophotometer, Scanning Electron Microscope, Energy Dispersive X-ray, X-ray diffractometer, and the Brunauer-Emmett Teller. The adsorption study was perfomed at different experimental conditions including pH, contact time, initial dye concentration, temperature, agitation speed, and biosobent dose. From the results of this study, the optimum biosorption of MB was achieved at 120 min contact time, pH 10, room temperature (298 K), 150 rpm agitation speed and dosage of 100 mg/150 mL dye solution. With 132.30 mgg-1 maximum sorption capacity, the Langmuir isotherm best describes the biosorption equilibrium data. At all initial concentrations, the biosorption kinetics of methylene blue onto the biosorbent fitted best to the pseudo-second order kinetics model, with R2 values ≥ 0.999 and qcal being similar to the qexp. The kinetics study also showed the involvement of intra-particle diffusion in the rate-determining step; although not as the sole limiting step of the sorption process. The results of the thermodynamics study showed the high feasibility, spontaneity, and exothermic nature of the biosorption of methylene blue onto the biosorbent. This study concludes that Roystnea regia fruit pericarp would make an economically viable and renewable biosorbent for practical eco-friendly sequestration of MB dye from wastewaters.
{"title":"Adsorptive Sequestration of Methylene Blue Dye from Aqueous Solution Using Novel Roystonea regia fruit Pericarp: Isotherm, Kinetics, and Thermodynamics","authors":"Adeola Ibi̇kunle, T. Osobami̇ro, Najeem Babari̇nde, Feyisara Adaramola","doi":"10.35378/gujs.1218734","DOIUrl":"https://doi.org/10.35378/gujs.1218734","url":null,"abstract":"The batch adsorptive sequestration of methylene blue from an aqueous solution using unripe Roystonea regia fruit pericarp biomass was investigated in this study. The characteristic nature of the biosorbent was studied using various analytical instruments including Fourier Transform Infra-red spectrophotometer, Scanning Electron Microscope, Energy Dispersive X-ray, X-ray diffractometer, and the Brunauer-Emmett Teller. The adsorption study was perfomed at different experimental conditions including pH, contact time, initial dye concentration, temperature, agitation speed, and biosobent dose. From the results of this study, the optimum biosorption of MB was achieved at 120 min contact time, pH 10, room temperature (298 K), 150 rpm agitation speed and dosage of 100 mg/150 mL dye solution. With 132.30 mgg-1 maximum sorption capacity, the Langmuir isotherm best describes the biosorption equilibrium data. At all initial concentrations, the biosorption kinetics of methylene blue onto the biosorbent fitted best to the pseudo-second order kinetics model, with R2 values ≥ 0.999 and qcal being similar to the qexp. The kinetics study also showed the involvement of intra-particle diffusion in the rate-determining step; although not as the sole limiting step of the sorption process. The results of the thermodynamics study showed the high feasibility, spontaneity, and exothermic nature of the biosorption of methylene blue onto the biosorbent. This study concludes that Roystnea regia fruit pericarp would make an economically viable and renewable biosorbent for practical eco-friendly sequestration of MB dye from wastewaters.","PeriodicalId":12615,"journal":{"name":"gazi university journal of science","volume":"52 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139320884","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}
The study presents electromagnetic scattering by arbitrarily located double strips with perfect electric and/or magnetic conducting surfaces. The study generalizes not only the physical dimension, location, and orientation of the strips but also, the boundary conditions on each strip are generalized and variable. It can be Dirichlet or Neumann boundary conditions. Since the study considers numerous parameters as the variable, the comparison between the present study and the literature is investigated in detail. Geometries such as parallelly located double strips with fractional boundary conditions, impedance double strips, and wedge problems are considered to compare. Besides, the proposed methodology is compared by the method of moments, the method of auxiliary sources, and the orthogonal polynomials approach. The suggested research investigates the electromagnetic scattering by finite wedge and arbitrarily located two strips with different boundary conditions and widths for the first time since each strip can have different widths and boundary conditions (Dirichlet or Neumann). The results reveal that the angle between the strips, the rotation of the strips, width of the strip have noticeable effects on the scattered field and total radar cross-sections. Between the strips, resonances are observed and their characteristics have a substantial dependency on the boundary conditions.
{"title":"Electromagnetic Scattering by Arbitrarily Located Electric and/or Magnetic Conducting Double-Strip","authors":"K. Karaçuha, Vasil Tabatadze","doi":"10.35378/gujs.1348483","DOIUrl":"https://doi.org/10.35378/gujs.1348483","url":null,"abstract":"The study presents electromagnetic scattering by arbitrarily located double strips with perfect electric and/or magnetic conducting surfaces. The study generalizes not only the physical dimension, location, and orientation of the strips but also, the boundary conditions on each strip are generalized and variable. It can be Dirichlet or Neumann boundary conditions. Since the study considers numerous parameters as the variable, the comparison between the present study and the literature is investigated in detail. Geometries such as parallelly located double strips with fractional boundary conditions, impedance double strips, and wedge problems are considered to compare. Besides, the proposed methodology is compared by the method of moments, the method of auxiliary sources, and the orthogonal polynomials approach. The suggested research investigates the electromagnetic scattering by finite wedge and arbitrarily located two strips with different boundary conditions and widths for the first time since each strip can have different widths and boundary conditions (Dirichlet or Neumann). The results reveal that the angle between the strips, the rotation of the strips, width of the strip have noticeable effects on the scattered field and total radar cross-sections. Between the strips, resonances are observed and their characteristics have a substantial dependency on the boundary conditions.","PeriodicalId":12615,"journal":{"name":"gazi university journal of science","volume":"4 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139320844","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}
Renewable energy systems are mostly used in the world due to their inexhaustible and non-polluting production. As a result of a large utilization of these energy sources in different areas, the electricity production rate is increasing every day. Previous studies clarified uses, modeling, configuration, energy management operation, and optimization objectives based on different energy sources. For this reason, this paper focuses on an overview of multi energy systems as renewable and conventional power sources with the integration of an energy storage system coupled to the on-off electrical network. Furthermore, a survey is done regarding global energy production, configuration energy systems, energy storage systems, power management strategies, and optimization methods based on different hybrid energy systems. Multiple optimization approaches have been implemented to reach the global best solution for the hybrid power systems. To ensure the best optimization result, it is preferable to take hybrid optimization methods into consideration. These methods have been invented recently and have proved their efficacy and performance mainly in power systems.
{"title":"Overview: Using Hybrid Energy System for Electricity Production Based on the Optimization Methods","authors":"Samia Sai̇b, Ramazan Bayindir, S. Vadi","doi":"10.35378/gujs.1328300","DOIUrl":"https://doi.org/10.35378/gujs.1328300","url":null,"abstract":"Renewable energy systems are mostly used in the world due to their inexhaustible and non-polluting production. As a result of a large utilization of these energy sources in different areas, the electricity production rate is increasing every day. Previous studies clarified uses, modeling, configuration, energy management operation, and optimization objectives based on different energy sources. For this reason, this paper focuses on an overview of multi energy systems as renewable and conventional power sources with the integration of an energy storage system coupled to the on-off electrical network. Furthermore, a survey is done regarding global energy production, configuration energy systems, energy storage systems, power management strategies, and optimization methods based on different hybrid energy systems. Multiple optimization approaches have been implemented to reach the global best solution for the hybrid power systems. To ensure the best optimization result, it is preferable to take hybrid optimization methods into consideration. These methods have been invented recently and have proved their efficacy and performance mainly in power systems.","PeriodicalId":12615,"journal":{"name":"gazi university journal of science","volume":"26 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139323083","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}
Reflective polarization conversions with a simplistic design of an ultrathin, single-layered, and multi-functional anisotropic metasurface as a polarization converter is utilized for Ku- and K-band applications. The designs with two substrate thicknesses (0.095λ0 and 0.069λ0, respectively) are capable of a cross-polarization converter (CPC) and a linear-to-circular (LTC) polarization conversion. The design with 0.095λ0 thickness achieves a CPC between 17.96 and 26.90GHz with the efficiency of more than 90% and a relative bandwidth of 40% under normal incidence. It maintains angular stability by altering the oblique incidence angles up to 300 with greater than 80% of the PCR in the K-band. Meanwhile, an LTC in two frequency bands, 10.30-10.53GHz and 28.65-29.70GHz, is also numerically demonstrated. The second design with 0.069 λ0 thickness provides a CPC above the PCR value of 87% in the frequency range from 10.46-23.05GHz (covering the entire Ku- and part of the K-band) with angular stability of 40 above the PCR value of 80%. In the meantime, an LTC with relative bandwidth of 75% in the frequency range from 9.53-9.79&24.74-25.27GHz is numerically revealed. These polarization converters exhibit relatively good performances of facile structure and multi-functional properties, which can be useful in Ku- and K-band applications.
利用超薄、单层和多功能各向异性元表面作为极化转换器的反射极化转换简易设计，用于 Ku 波段和 K 波段应用。两种衬底厚度（分别为 0.095λ0 和 0.069λ0）的设计能够实现交叉偏振转换器（CPC）和线性到圆形偏振转换器（LTC）。厚度为 0.095λ0 的设计可在 17.96 和 26.90GHz 之间实现 CPC，效率超过 90%，正常入射条件下的相对带宽为 40%。通过改变斜入射角，它能保持角度稳定性，最高可达 300 度，在 K 波段的 PCR 超过 80%。同时，还对 10.30-10.53GHz 和 28.65-29.70GHz 两个频段的 LTC 进行了数值演示。厚度为 0.069 λ0 的第二种设计在 10.46-23.05GHz 频率范围内（覆盖整个 Ku 波段和部分 K 波段）的 CPC 高于 PCR 值 87%，角度稳定性为 40，高于 PCR 值 80%。同时，在 9.53-9.79 和 24.74-25.27GHz 频率范围内，数值显示出相对带宽为 75% 的 LTC。这些偏振转换器具有结构简单、功能多样等良好性能，可用于 Ku 波段和 K 波段应用。
{"title":"Reflective Polarization Conversion with Multi-Functional, Ultrathin Metasurface for Ku- and K-Band Applications","authors":"Ahmet Teber","doi":"10.35378/gujs.1232730","DOIUrl":"https://doi.org/10.35378/gujs.1232730","url":null,"abstract":"Reflective polarization conversions with a simplistic design of an ultrathin, single-layered, and multi-functional anisotropic metasurface as a polarization converter is utilized for Ku- and K-band applications. The designs with two substrate thicknesses (0.095λ0 and 0.069λ0, respectively) are capable of a cross-polarization converter (CPC) and a linear-to-circular (LTC) polarization conversion. The design with 0.095λ0 thickness achieves a CPC between 17.96 and 26.90GHz with the efficiency of more than 90% and a relative bandwidth of 40% under normal incidence. It maintains angular stability by altering the oblique incidence angles up to 300 with greater than 80% of the PCR in the K-band. Meanwhile, an LTC in two frequency bands, 10.30-10.53GHz and 28.65-29.70GHz, is also numerically demonstrated. The second design with 0.069 λ0 thickness provides a CPC above the PCR value of 87% in the frequency range from 10.46-23.05GHz (covering the entire Ku- and part of the K-band) with angular stability of 40 above the PCR value of 80%. In the meantime, an LTC with relative bandwidth of 75% in the frequency range from 9.53-9.79&24.74-25.27GHz is numerically revealed. These polarization converters exhibit relatively good performances of facile structure and multi-functional properties, which can be useful in Ku- and K-band applications.","PeriodicalId":12615,"journal":{"name":"gazi university journal of science","volume":"269 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139323011","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}
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