gazi university journal of science最新文献_第2页

Lean Six Sigma Studies in Türkiye: A Literature Review 土耳其的精益六西格玛研究：文献综述

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gazi university journal of science Pub Date : 2023-10-31 DOI: 10.35378/gujs.1176313

Nurcan Deniz, İlknur Tükenmez

{"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":null,"pages":null},"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}

引用次数: 0

An Investigation of the Chemical Composition of Bottom Sediments from Dried Lake Gavur of Türkiye by Using XRF and Multivariate Data Analysis 利用 XRF 和多元数据分析对土耳其干涸的加武尔湖湖底沉积物化学成分的研究

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gazi university journal of science Pub Date : 2023-10-23 DOI: 10.35378/gujs.1240178

Muhammet Topuz, M. Keskin, Murat Karabulut, Nurgül KARLIOĞLU KILIÇ

{"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":null,"pages":null},"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}

引用次数: 0

Adsorptive Sequestration of Methylene Blue Dye from Aqueous Solution Using Novel Roystonea regia fruit Pericarp: Isotherm, Kinetics, and Thermodynamics 利用新颖的 Roystonea regia 果皮对水溶液中的亚甲基蓝染料进行吸附螯合：等温线、动力学和热力学

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gazi university journal of science Pub Date : 2023-10-10 DOI: 10.35378/gujs.1218734

Adeola Ibi̇kunle, T. Osobami̇ro, Najeem Babari̇nde, Feyisara Adaramola

{"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":null,"pages":null},"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}

引用次数: 0

Electromagnetic Scattering by Arbitrarily Located Electric and/or Magnetic Conducting Double-Strip 任意位置的导电和/或导磁双层带的电磁散射

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gazi university journal of science Pub Date : 2023-10-10 DOI: 10.35378/gujs.1348483

K. Karaçuha, Vasil Tabatadze

{"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":null,"pages":null},"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}

引用次数: 0

Overview: Using Hybrid Energy System for Electricity Production Based on the Optimization Methods 概述：基于优化方法使用混合能源系统发电

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gazi university journal of science Pub Date : 2023-10-05 DOI: 10.35378/gujs.1328300

Samia Sai̇b, Ramazan Bayindir, S. Vadi

{"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":null,"pages":null},"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}

引用次数: 0

Reflective Polarization Conversion with Multi-Functional, Ultrathin Metasurface for Ku- and K-Band Applications 用于 Ku 和 K 波段应用的多功能超薄金属表面反射偏振转换器

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gazi university journal of science Pub Date : 2023-10-05 DOI: 10.35378/gujs.1232730

Ahmet Teber

{"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":null,"pages":null},"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}

引用次数: 0

New Steady State Current Error Limiters for PMSM Drives 用于 PMSM 驱动器的新型稳态电流误差限制器

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gazi university journal of science Pub Date : 2023-10-04 DOI: 10.35378/gujs.1253423

Hemantha Kumar Ravi, Lenın N C

引用次数: 0

Shallow Convolutional Neural Network for Gender Classification Based on Hand 基于手的浅卷积神经网络性别分类

gazi university journal of science Pub Date : 2023-09-25 DOI: 10.35378/gujs.1246486

Md. KHALİLUZZAMAN

引用次数: 0

Characterizations of Filter Convergent in Terms of Ideal 滤波器在理想条件下收敛的特性

gazi university journal of science Pub Date : 2023-09-24 DOI: 10.35378/gujs.967261

Shyamapada MODAK, Kulchhum KHATUN, Jiarul HOQUE

引用次数: 0

Development of a Controlled Released System Based on IPN Types Hydrogel for Cartilage Repair 基于IPN型水凝胶的软骨修复控制释放系统的研制

gazi university journal of science Pub Date : 2023-09-08 DOI: 10.35378/gujs.1295326

Evrim SEVER, Mehlika PULAT

{"title":"Development of a Controlled Released System Based on IPN Types Hydrogel for Cartilage Repair","authors":"Evrim SEVER, Mehlika PULAT","doi":"10.35378/gujs.1295326","DOIUrl":"https://doi.org/10.35378/gujs.1295326","url":null,"abstract":"The aim of this study is to develop a controlled Fluconazole and Naproxen releasing system for cartilage repair. A series of interpenetrating polymer network (IPN) type of hydrogels were prepared by using 2-Hydroxyethyl methacrylate (HEMA) and gelatin in different ratios. The hydrogels were synthesized by using ammonium persulfate (APS) and sodium metabisulfite (SBS) as initiator pair and ethylene glycol dimethacrylate (EGDMA) and glutaraldehyde (GA) as cross linkers. The prepared hydrogels were characterized via hydrogel formation and swelling/degradation measurements, Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM) analysis. From swelling tests, it is observed that semi-IPN hydrogels swell much more than full-IPNs which crosslinked by two agents, EGDMA and GA. The higher ratios of HEMA/gelatin negatively affect swelling values. In general, the IPN hydrogel discs were not affected by the variation of temperature. The release studies of Fluconazole and Naproxen were performed at 37 ⁰C and it is found that the swelling and release profiles were similar to each other. The releases of drugs increase rapidly at first and then complies nearly 36 h-48 h. Because of the looser and porous structure, semi-IPN hydrogels have higher release values than full-IPNs.","PeriodicalId":12615,"journal":{"name":"gazi university journal of science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136364205","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}

引用次数: 0