Sürdürülebilir Kalkınma Amaçları

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• MakaleYayıncıda açık erişim2023Scopus SJRQ1/r/munzur/2453
  Evaluation of the effect of silica fume on the fresh, mechanical and durability properties of self-compacting concrete produced by using waste rubber as fine aggregate

  Etli, Serkan

  The supply of sand, which is obtained by disposing of natural resources for the purpose of concrete production and in accordance with production standards, is increasing rapidly and therefore its amount is rapidly depleted. A study is presented that aims to reduce the aggregate content by using this waste tire aggregate (WTA) in the construction industry, and thus, a sustainable production and conservation of nature is the basis. The water/binder ratio used in the study is kept constant as 0.39 and the binder dosage as 550 kg/m3. WTA and SF are replaced with sand and cement at the ratios of 5%, 10% and 15% by volume, and 5% and %15 b y weight, respectively. The fresh (slump flow, V-funnel, and L-box) and hardened (axial compression, splitting tensile strength, flexural tensile strength, diagonal tensile strength, and modulus of elasticity, chlorine penetration and sorptivity) properties of self-compacting concrete (SCC) mixtures produced in this way are evaluated. For the mechanical and durability tests, a total of approximately 500 SCC (100 × 100 × 500 mm: prism, 100 × 100 × 100 mm: cube and 100 × 200 mm: cylindrical) samples are produced. The mechanical experiments of SCC were carried out at 28-, 56- and 90-days age. The test results have shown that WTA substitute concrete, which can be used in terms of civil engineering in terms of all these features, has shown that it has sufficient performance.

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  AtıfScopus51·WoS43·OpenAlex55

  İncele
• MakaleYalnız künye2020Scopus SJRQ1/r/munzur/3702
  Roles of aluminium shavings and calcite on engineering properties of cement-based composites

  Gulmez, Nihan

  In the construction industry, which large amounts of raw materials are consumed, substituting even small parts of concrete components with waste materials may lead to significant savings in consumed energy and natural resources hence support prevention of environmental pollution. In this study, an experimental program was carried out to find a reliable and eco-friendly method for eliminating large quantities of calcite powders originating from the marble processing industry and also aluminium shavings, a nondisposable product of metal working and shaping industry. Physical, mechanical and microstructural properties of the mortars produced with industrial wastes at different replacement percentages were evaluated. Adding up to 20% calcite to the mortar mixtures instead of cement did not cause a significant change in water absorption values compared to control mortar. In addition, the gradual increase of aluminium shavings in all mortar mixtures resulted in a significant decrease in apparent porosity. In mortars based on 10% calcite, an increase of 52% in 7-days flexural strength was achieved with the addition of 4% aluminium shavings.

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  AtıfScopus23·WoS20·OpenAlex24

  İncele
• MakaleYalnız künye2020Scopus SJRQ1/r/munzur/3692
  A scale to measure sustainable campus services in higher education: “Sustainable Service Quality”

  Ozdemir, Yasal; Kaya, Sema Kayapinar; Turhan, Erkan

  This study aims to develop a measuring tool which can address two independent research areas in the literature: Sustainability in higher education and service quality in higher education. Both subjects are studied independently in the literature, showing a need for an integrated approach that bridges these areas. For achieving this purpose, a new scale was developed based on a questionnaire applied to two universities in Turkey. The scale aimed to measure the perceptions of the students regarding the quality of sustainable campus services. The questionnaire consisted of 22 questions on several aspects of campus services which are related to sustainability. A total of 234 samples were used for Exploratory Factor Analysis for determining the underlying structures in the data set. The scale was validated with satisfactory Kaiser-Meyer Olkin and Bartlett's test results. Five dimensions were extracted, which represent sustainable service quality. After validation, the scale was applied to two universities located in geographically and socio-economically different regions of Turkey. The term chosen for the proposed combined scale is Sustainable Service Quality (SusServQual). With additional data, t-tests were applied to 308 students aiming to compare the two universities based on perceived quality scores. The results show that the university located in the socio-economically more developed region performed better regarding the overall satisfaction score and four of the five dimensions. The scores were also weighted utilizing a modified method of Analytical Hierarchy Process. Instead of crisp numbers which forces the decision maker to think in mathematical terms while comparing criteria, linguistic terms, each of which corresponds to a fuzzy number were used. Thus, a more accurate evaluation was obtained where the decision maker's subjectivity and ambiguity of the situation are important.

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  AtıfScopus62·WoS50·OpenAlex77

  İncele
• MakaleYalnız künye2020Scopus SJRQ1/r/munzur/3563
  Futuristic airport: A sustainable airport design by integrating hesitant fuzzy SWARA and hesitant fuzzy sustainable quality function deployment

  Kayapinar Kaya, Sema; Erginel, Nihal

  The interest of researchers and airport authorities towards sustainable airports is increasing day by day. Futuristic airport designs will be innovative in achieving sustainable development practices such as clean and affordable energy, protection of natural resources, waste reduction, natural features and green space around an airport, sustainable transportation system, natural storm water management of airports, etc. In classical Quality Function Deployment, crisp numbers are used to determine the priorities of the passenger requirements, design requirements, and their relationship matrix to evaluate airport quality. However, vagueness and impreciseness are inevitable uncertainties in those kinds of human judgments, which are generally realized by linguistic terms, and traditional Quality Function Deployment is not associated with “sustainability.” The main contribution of this paper is to present a new approach that integrates Hesitant Fuzzy Stepwise Weight Assessment Ratio Analysis and Hesitant Fuzzy Sustainable Quality Function Deployment method to enhance the sustainable airport quality. Hesitant fuzzy set theory reflects the hesitancy in human nature while making a decision to the fuzzy numbers, compared to other fuzzy set theories, such as traditional fuzzy sets, type-2 fuzzy sets, etc. In this study, the importance degrees of sustainable passenger requirements were evaluated by considering Hesitant Fuzzy Stepwise Weight Assessment Ratio Analysis in the first stage of Hesitant Fuzzy Sustainable Quality Function Deployment method. Then sustainable design requirement was prioritized to develop the sustainable quality management of the airport. Finally, a case study concerning the sustainable development of the airport was used to elucidate the feasibility and rationality of the proposed framework. The results obtained from the case study showed that Hesitant Fuzzy Sustainable Quality Function Deployment could be a practical and structural methodology in the early planning stage of a sustainable airport design.

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  AtıfScopus68·WoS54·OpenAlex74

  İncele
• MakaleYalnız künye2019Scopus SJRQ1/r/munzur/3695
  Supply-driven rebalancing of disassembly lines: A novel mathematical model approach

  Mete, Suleyman; Çil, Zeynel Abidin; Celik, Erkan; Ozceylan, Eren

  In recent years, the interest of disassembly line has increased owing to the economic reasons and increase of environmental awareness. The balancing of the disassembly line is one of the factors affecting directly the performance of the process. Companies with a line used effectively can gain many advantages in terms of economic aspect and it facilitates competition the companies with others. Moreover, uncertainties end-of-life products characteristics and quantity of supply/demand causes reassigned of task and altering cycle time. Rebalancing of disassembly line is required in this situation. In this study, a novel mixed integer programming model is proposed. Firstly, disassembly line balance is created, and then according to the given new supply, tasks are reselected and reassigned to the workstations. A real case study is presented. The generated test problems are also analyzed using proposed mathematical model. Through the analysis of rebalancing the existing disassembly line, it has been identified that an existing balance might have been changed to accommodate changes in the desired output rate in order to cope up with the variation of the cycle time.

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  AtıfScopus31·WoS27·OpenAlex31

  İncele
• MakaleYalnız künye2018Scopus SJRQ1/r/munzur/3537
  A comparative outline for quantifying risk ratings in occupational health and safety risk assessment

  Gul, Muhammet; Ak, M. Fatih

  The concept of risk assessment has been introduced as an examination of safety in the workplace to enable assessments as to whether sufficient precautions have been taken or if more should be done to prevent potential harm. Hazardous industries have faced serious fatalities related to work, workplaces, and workers as a consequence of their high-risk processes. Therefore, in this work, a novel and comparative methodology for quantifying risk ratings in occupational health and safety risk assessment is proposed. A 5 × 5 risk matrix is initially determined, and the fuzzy technique for order preference by similarity to ideal solution (FTOPSIS) method is then applied to rank identified hazards. As a novelty to the knowledge, two parameters of the 5 × 5 matrix method, likelihood and severity, are subjectively assessed by occupational health and safety experts, and then importance levels for these parameters are determined using the Pythagorean fuzzy analytic hierarchy process (PFAHP). In the proposed approach, analysts use linguistic terms and Pythagorean fuzzy sets, which provide greater independence in their evaluations. An outline that enables comparison of the results of this study with the circumcenter of centroids method and the fuzzy AHP-fuzzy VIKOR integrated method in quantifying risk ratings is also provided. In order to present the practicality of this work, a case study in an underground copper and zinc mine is carried out.

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  AtıfScopus194·WoS153·OpenAlex211

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