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Koleksiyondaki öğeler
- MakaleYalnız künye2020Scopus SJRQ3A fuzzy-based occupational health and safety risk assessment framework and a case study in an international port authority
Gul, Muhammet
Ports are complex systems that play a crucial role in the transportation of maritime-related products and services. Since ports face various safety issues in design, installation, operation and maintenance processes, there are many aspects open for improvement in Occupational Health and Safety risk assessment and it is required to deal with risks, reduce them to an acceptable level and control. To struggle with emerging risks and manage this process better, a risk assessment framework is proposed for ports in this study. A case study is performed in a Turkish international port authority using the proposed framework. Fuzzy Analytic Hierarchy Process (FAHP), which is a commonly used fuzzy multi-criteria decision-making method, was used in weighting two risk factors: likelihood and severity. The orders of priority of hazards were then determined by a fuzzy-based VIKOR method based on the output of FAHP. The proposed framework overcomes some drawbacks, including a lack of assignment on the weight to two risk assessment factors and lack of the high dependence of the prioritisation on the experts’ opinions. To validate the results, a sensitivity analysis was conducted. In conclusion, the study contributes to the applicability of the proposed framework to assess the risks in ports and provides a distinct risk prioritisation.
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İncele - MakaleYalnız künye2019Uptake of some elements with aquatic plants exposed to the effluent of wastewater treatment plant
Tatar, S.; Öbek, E.; Arslan Topal, E.I.; Topal, M.
In this study, in the removal of macro (P, S, Na, K, Ca, Mg) and micro (Sb, Ba, Co, Cu, Fe, Pb, Mn, Hg, Mo, Se, Ag, Zn) elements in the effluent of Elazig Wastewater Treatment Plant, the efficiency of Lemna minor L. and Lemna gibba L. has been studied comparatively. For this aim, fronds of these plants have been adapted to the effluent of the treatment plant that feeds pilot scale reactors. The concentrations of elements in fronds harvested during the working period were analyzed by ICP/MS. The analytical results show that Lemna minor L. has a high accumulation potential for P, Sb, Ba, Co, Fe, Pb, Mn, Hg, Ag and Zn while Lemna gibba L. has a high accumulation potential for S, Na, Ca, Mg, Cu, Mo and Se. The results show that Lemna minor L. and Lemna gibba L. can be used as phytoremediators of wastewater.
AtıfScopus10OpenAlex6İncele - MakaleYayıncıda açık erişim2018Scopus SJRQ3A FUZZY DEMATEL MODEL PROPOSAL FOR THE CAUSE AND EFFECT OF THE FAULT OCCURRING IN THE AUXILIARY SYSTEMS OF THE SHIPS’ MAIN ENGINE
Balin, A.; Demirel, H.; Celik, E.; Alarcin, F.
The ship engine room has a structure that meets a number of needs related to administrative conditions. Even if a simple mechanical error is considered to be the addition of human errors into the complex structure of the engine room, it can lead to undetected loss. How the causes and effects of the detected faults affect the system is as important as an effective fault detection system to detect the fault and take immediate action against any possible engine failure. This study reveals the causes of problems occurring in the main engine auxiliary systems including cooling, lubricating, cooling oil and fuel systems, and the extent of these problems affecting the system. While the Decision Making Trial and Evaluation Laboratory supports to identify and analyze the error detection of auxiliary systems with respect to causal effect relation diagram, fuzzy sets deal with the uncertainty in decision-making and human judgements through the DEMATEL. Therefore, fuzzy DEMATEL approach is applied to examine the causes and the weights of the faults and their relation to each other in the auxiliary systems. When we look at the result of the proposed approach, fuel oil pump failures has more impact on the all system and air cooler problems has the second highest place among the all errors.
AtıfOpenAlex1İncele - MakaleAçık Erişim2020Scopus SJRQ3An ethnobotanical survey of medicinal plants in ballakayati (Erbil, north Iraq)
Kawarty, Awara Mohammed A.M.A.; Behçet, Lütfi; Çakilcioğlu, Uğur
This study aims to identify wild plants used for medical purposes by local people of the Ballakayati district of Erbil in North Iraq, and to determine the local names and uses of those plants. The study was carried out for approximately 3 years between 2016 and 2018. During this period of time, 85 plant specimens were collected. Demographic characteristics of the participants, names of the local plants, used parts of these plants and their preparation methods were investigated and recorded. In the literature analysis of the plants used in this study, 85 plants were found to be used for medicinal purposes while 3 plants were not found in the literature records. Local plant names differ due to local dialects in North Iraq. Locals benefit from the wild plants growing in their districts. In this area, it was found that locals use 85 plants from 38 families for curative purposes. The medicinal plants were used for the treatment of many diseases, mostly for the treatment of a cold, shortness of breath, and heart and gastrointestinal diseases. It was determined that the plants we identified in this study were used directly or as infusion or decoction. The most considerable medicinal plants were Mentha longifolia (L.) L. subsp. noeana (Briq.) Briq. (UV:0.38), Urtica dioica L. (UV:0.38). Furthermore, plants used for medicinal purposes are dried and stored for using them in winter. The medicinal use of Rhaponticum repens (L.) Hidalgo and Tanacetum polycephalum Sch.Bip. subsp. argyrophyllum (K.Koch) Podlech. that we found in this area were recorded for the first time. Different use of those plants were observed in this study.
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İncele - MakaleAçık Erişim2020Scopus SJRQ2The effect of graphene nanoplatelets on technical properties of micro- and nano-sized TiO2 matrix: a comparative research study on electrical and optical characteristics
Güler, Ömer; Ayhan, Hakan; Başgöz, Öyküm; Yavuz, Çağdaş; Albayrak, M. Gökhan; Evin, Ertan; Safa, Hasan; Yahia, Ibrahim S.
In this study, titanium dioxide (TiO2)-based graphene nanoplatelets (GNPs)-reinforced composite materials were produced and the electrical and optical properties of the composite materials were investigated. Graphene, which was used as a reinforcing material, was produced by using liquid-phase exfoliation method. While the TiO2 used as matrix material was commercially available for the first group of samples, it was produced by using the sol–gel method for the second group of the samples. Different rates of graphene were added to the TiO2 powders which were commercially available and produced by using sol–gel method. GNPs used as a reinforcing material were subjected to TEM analysis. The resulting composite materials were structurally examined in SEM and XRD. Then, the changes in electrical conductivity of these composites under the impact of temperature were measured. UV–Vis spectrometers of the samples were taken and their optical properties were determined. When temperature-based electrical examination of the produced composite materials was performed, an increase was observed on the electrical conductivity values in both groups of samples as a result of addition of the reinforcing element. In addition, TiO2-containing composites produced by using sol–gel method had lower electrical conductivity comparing with commercially purchased TiO2-containing composites especially at high temperatures. In the optical measurements, it was observed that there was an increase in the optical bandgap energy range values with GNPs reinforcement but a decrease in the reflectance values.
AtıfOpenAlex2İncele - MakaleYayıncıda açık erişim2020Scopus SJRQ4Bioremediation of fluazifop-p-butyl herbicide by some soil bacteria isolated from various regions of Turkey in an artificial agricultural field
Erguven, Gokhan Onder; Nuhoglu, Yasar
The bioremediation rate of fluazifop-p-butyl (C19H20F3NO4) was monitored. Bacteria were isolated in agricultural soil samples. Fifteen sterilised glass jars were inoculated with 2, 5, 10, 20 cm3 of a homogenised bacterial mixture (109 CFU/cm3), then sterile agricultural soil and 60 µg of fluazifop-p-butyl (in liquid form) were added to each jar. Each week, filtrated water drained from bottles was analysed for fluazifop-p-butyl concentration, chemical oxygen demand (COD), biochemical oxygen demand (BOD5) and total organic carbon (TOC). Additionally, pH and dissolved oxygen concentration were monitored. The highest biodegradation rate was observed in the soil sample containing 20 cm3 of the culture media. In this media, fluazifop-p-butyl, COD, BOD5 and TOC removals were measured as 91, 83, 96 and 86%, respectively, at the end of the 2 months. The DO level was measured between 3 and 6 mg O2/dm3 in the first month for all cultures. An increase of pH was recorded during the first month and after this time a pH decrease was noted.
AtıfScopus5WoS5OpenAlex4İncele - MakaleAçık Erişim2018Scopus SJRQ2Observations of crayfish plague infections in commercially important narrow-clawed crayfish populations in Turkey
Kokko, Harri; Harlioglu, Muzaffer M.; Aydin, Hamdi; Makkonen, Jenny; Gökmen, Gökhan; Aksu, Önder; Jussila, Japo
We studied the presence of possible Aphanomyces astaci infections in eight Turkish narrow-clawed crayfish (Astacus leptodactylus) populations by analyzing the prevalence and genotypes of the disease agent A. astaci. The qPCR analyses revealed A. astaci infection in seven of the studied eight populations, with the agent level A2 or higher. The agent levels among the infected populations varied from A0 to A5, i.e., from negative to high level of infection, based on qPCR ranking. Based on the sequencing of the chitinase gene and the mitochondrial ribosomal rnnS and rnnL subunits, we detected both A (As) and B (PsI) haplogroups of A. astaci in our samples, with each of the studied populations being carriers of only one haplotype. The results confirm previous detections of A. astaci in Turkish narrow-clawed crayfish populations and reveal, that both A and B haplogroup A. astaci carriers exist widely in A. leptodactylus populations of Turkey.
AtıfScopus28WoS29OpenAlex23İncele - MakaleAçık Erişim2018Scopus SJRQ1The investigation of the shelf life at 2 ± 1 °C of Luciobarbus esocinus fillets packaged with films prepared with the addition of different essential oils and chitosan
Karaton Kuzgun, Nermin; Gürel İnanlı, Ayşe
In this study, the chemical, microbiological and sensory changes during storage at 2 ± 1 °C of Luciobarbus esocinus fillets coated with edible films prepared with chitosan incorporation of thyme, clove, rosemary essential oils were examined. To create the experimental samples, a total of six groups of L. esocinus fillets coated with different edible films (normal, vacuum-packed, chitosan, chitosan with added thyme oil, chitosan with added clove oil, and chitosan with added rosemary) were used. The food composition of the fillets and experimental samples were determined after they had been coated with edible films. The results of analysis showed that, the preservation period of fresh fillets ended on day 12th, that of vacuum-packed fillets on day 15th, that of fillets coated with chitosan incorporation of rosemary on day 27th, that of fillets coated with chitosan incorporation of thyme and chitosan incorporation of cloves on day 30th. In comparison with the control group, fish spoilage was significantly delayed in samples coated with chitosan incorporation of thyme and chitosan incorporation of cloves (p < 0.05). The lowest bacterial growth, values of PV, TBA and TVB-N were obtained in fish samples coated with thyme + chitosan and cloves + chitosan. In terms of the general acceptability of the fish, as determined by qualified panelists, it was determined that the highest score was given to the experimental group to which essential oil of clove had been applied.
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İncele - MakaleYalnız künye2019Scopus SJRQ2Evaluation of health risks from exposure to arsenic and heavy metals through consumption of ten fish species
Varol, Memet; Kaya, Gülderen Kurt; Sünbül, Muhammet Raşit
In this study, the levels of 11 heavy metal(loid)s (HMs) were determined in ten different fish species (wild, farmed, freshwater, and marine) frequently consumed in Turkey and compared with the maximum permissible limits (MPLs) established by international standards. Also, human health risks for the consumers were assessed. Among 11 HMs, only Al and Cr levels did not show significant differences among fish species. The highest concentrations of As were found in red mullet, which is a demersal fish. The average concentrations of Cd, Cr, Cu, and Pb in all fish species were below the MPLs, whereas those of Zn in European anchovy and Mediterranean horse mackerel, and that of inorganic As in red mullet exceeded the MPLs. The highest and lowest toxic metal contents (Al, As, Cd, and Pb) were recorded in red mullet and farmed rainbow trout, respectively. The estimated daily intakes of HMs in each fish species were very lower than their corresponding tolerable daily intakes, suggesting the daily intake of HMs through fish consumption would not pose health risks for the consumers. The target hazard quotient for individual HMs and hazard index for combined HMs in fish species were below 1, which indicated that non-carcinogenic health effects are not expected. The carcinogenic risk results revealed that there was a carcinogenic risk from exposure to inorganic As via the consumption of red mullet. Among all investigated fish species, rainbow trout and common carp were safer in terms of both non-carcinogenic and carcinogenic risks from exposure to HMs.
AtıfScopus72WoS63OpenAlex82İncele - Kitap BölümüYalnız künye2020Homoploid Hybridization and Its Role in Emergence and Diversity of the Genus Origanum L. (Lamiaceae)
Dirmenci, Tuncay; Arabacı, Turan; Özcan, Taner; Yazıcı, Türker; Martin, Esra; Çelenk, Sevcan; Açar, Mikail; Üzel, Devrim
Hybrid specimens can be occurred as same ploidy level (homoploidy) or not (polyploidy) with its parents. Homoploid hybrids are originated without any change in their ploidy level (2n) and polyploid hybrids are produced with the change in ploidy level (3n, 4n etc.). According to recent studies, the frequency of natural hybridization (homoploid and polyploid) has been estimated to 25% of all flowering plants. Recent studies show that the genus Origanum has homoploid hybrids. Hybridization is a common phenomenon among the species of Origanum in overlapping distribution habitats (natural or cultivated areas). Ietswaart suggested that the hybridization process is a significant factor in the speciation of Origanum, and Origanum is probably caused by the hybridization of the old tribe Saturejeae (now tribe Mentheae) genera. Based on the hypothesis of Ietswaart, we can discuss the emergence of the genus Origanum, its intrageneric speciation and its hybrids having the possibility for speciation via hybridization using morphological and cytological evidence. During the field studies, it was seen that many populations of wide-distributed species were overlapping, and some Origanum putative hybrid specimens were also observed in these overlapping areas with morphological differences from their parents. All studied Origanum species and hybrids have 2n = 30 chromosome numbers to define homoploidy. Palynological characters were revealed, and intermediate pollen structure (size, P/E ratio etc.) was seen in the hybrids between their parents. In addition, DNA extractions were done from all the hybrids and their parents. nrITS DNA was sequenced. Hybrid specimens have some heterozygous DNA loci in comparison to their parents. This study presents some evidence about homoploid the hybridization of the genus Origanum put forward by Ietswaart. If habitat, ecological and geographic isolations occur between the hybrids and their parents, these hybrids can be speciation via homoploid hybridization in the future.
AtıfScopus4İncele - Kitap BölümüYalnız künye2020Ideology of children animation series in Turkey: The case of Rafadan Tayfa
Özsel, Kadriye Töre
Cultural commodities take shape in accordance with the socio-political and ideological framework of the system in which they are produced. The aim of this chapter is to reveal that ideological framework for a Turkish animated series for children. The chapter is based upon ideology-critique perspective and selected series is Rafadan Tayfa. It is broadcasted on the kids channel of national broadcasting company TRT, was the most popular domestic animation series in April 2017. Selected chapters of the series are examined in accordance to Giannetti's methodological approach to identify ideological leanings in movies. It is found that the series has mild conservative leanings and presents a partly imagined "traditional neighborhood lifestyle" as an ideal form that is longed for.
- MakaleAçık Erişim2020Scopus SJRQ3Geochemical, stable (O, c, and b) and radiogenic (sr, nd, pb) isotopic data from the eskişehir-kızılcaören (nw-anatolia) and the malatya-kuluncak (e-central anatolia) f-ree-th deposits, Turkey: Implications for nature of carbonate-hosted mineralization
Çimen, Okay; Corcoran, Loretta; Kuebler, Corinne; Simonetti, Stefanie S.; Simonetti, Antonio
In Turkey, the largest fluorine (F)-rare earth element (REE)-thorium (Th) deposits are located within the Eskişehir-Kızılcaören (north-western Anatolia) and the Malatya-Kuluncak (east-central Anatolia) regions, and these are associated with Oligocene extensional alkaline volcanic and Late Cretecaous-Early Paleocene postcollisional intrusive rocks, respectively. In the Kızılcaören region, the basement units include the Triassic Karakaya Complex and the Late Cretaceous oceanic units (Neotethyan suture) that are cut and overlain by phonolite and carbonatite intrusions and lava flows. In the Kuluncak region, the plutonic rocks are mainly composed of syenite, quartz syenite, and rare monzonite, and these cut the late-Cretaceous Karapınar limestone, which hosts the F-REE-Th mineralization in contact zones. A carbonatite sample from the Kızılcaören region displays both a total rare earth element (TREE) concentration (4795 ppm) and δ11B (–6.83‰) isotope composition consistent with mantle-derived carbonatite; whereas it is characterized by heavier δ13C (+1.43‰) and δ18O (+20.23‰) isotope signatures compared to those for carbonatites worldwide. In contrast, the carbonates which host the F-REE-Th mineralization in the Kuluncak region are characterized by lower TREE concentrations (5.13 to 55.88 ppm), and heavier δ13C (–0.14 to –0.75‰), δ18O (+27.36 to +30.61‰), and δ11B (+5.38 to +6.89‰) isotope ratios compared to mantle-derived carbonatites. Moreover, the combined initial87Sr/86Sr (0.70584 to 0.70759) and143Nd/144Nd (0.512238 to 0.512571) isotope ratios for samples investigated here are distinct and much more radiogenic compared to those for carbonatites worldwide, and therefore indicate significant crustal input and/or hydrothermal metasomatic-related alteration. Overall, stable and radiogenic isotope data suggest that the host carbonate rocks for the F-REE-Th mineralization in both the Kızılcaören and the Kuluncak regions consist of hydrothermally metasomatized carbonatite and limestone, respectively. The mineralization in the Kızılcaören region may potentially be related to carbonatite magmatism, whereas the mineralization in the Kuluncak region, which most likely formed through interactions between the plutonic rocks and surrounding limestone at contact metamorphism zone, involved hydrothermal/magmatic fluids associated with extensive postcollisional magmatism.
AtıfScopus15WoS14OpenAlex18İncele - Kitap BölümüYalnız künye2020Microbial release of exopolymeric substances and their role in removal of pollutants from wastewater
Işıl Arslan Topal, E.; Topal, Murat
Activated sludge samples were seasonally collected from the aeration tanks of the Municipal Wastewater Treatment Plant located in Elazığ city (Turkey). Mixed liquor suspended solids (MLSS), mixed liquor volatile suspended solids (MLVSS), total solids (TS), suspended solids (SS), volatile solids (VS), chemical oxygen demand (COD), and sludge volume index (SVI) of the activated sludge were seasonally monitored in the treatment plant. Exopolymeric substances (EPS) were extracted in the samples collected. The EPS decreased in summer, while the EPS content was the highest in winter. The TB-EPS part of EPS was higher than the LB-EPS part of the EPS in all seasons. The lowest TB-EPS and LB-EPS were determined in summer, while the highest TB-EPS and LB-EPS were determined in winter. The carbohydrate, protein, and humic substance fractions of TB-EPS and LB-EPS followed the order of protein > carbohydrate > humic substance in all seasons. There was a negative correlation between the EPS content and SVI. The relationships between EPS and the removal efficiencies of TS, SS, and VS were quite low, while the relationship between COD removal and EPS was quite high.
AtıfScopus1OpenAlex1İncele - MakaleYalnız künye2019Scopus SJRQ1Pythagorean fuzzy VIKOR-based approach for safety risk assessment in mine industry
Gul, Muhammet; Ak, M. Fatih; Guneri, Ali Fuat
Introduction: Underground mining is considered one of the most hazardous industries and is often associated with serious work-related fatalities; this paper addresses job-related hazards and associated risks. Method: A risk assessment approach is proposed (Pythagorean fuzzy environment) and a case study is carried out in an underground copper and zinc mine. Results: Results of the study demonstrate that hazards can be categorized into different risk levels via compromised solutions of the fuzzy approach. Conclusion: The study provides a theoretical contribution by suggesting a Pythagorean fuzzy numbers-based VlseKriterijumska Optimizacija I Kompromisno Resenje (PFVIKOR) approach. Moreover, it contributes to improving overall safety levels of underground mining by considering and advising on the potential hazards of risk management. Practical applications: The proposed approach will improve the existing safety risk assessment mechanism in underground copper and zinc mining.
AtıfScopus184WoS156OpenAlex180İncele - MakaleYalnız künye2020Scopus SJRQ3Investigation of the Effect of Operating Conditions Change on Water Hammer in Hydroelectric Power Plants
Kahraman, Gökhan
Renewable energy sources do not harm the environment, and they contribute greatly to national economies. Hydraulic energy is the leading renewable energy source. Hydraulic energy is used more widely than other renewable energy sources around the world. This situation of hydraulic energy makes it important to solve the faults in hydraulic turbine-generator units. In this study, water hammer impacts have been investigated. This issue is important and can be dangerous in hydroelectric power plants. As a result of the research, the optimum sudden shutdown time of the adjusting wings in the snail is determined by considering the different operating conditions of a hydroelectric power plant. When the turbine-generator units are operated according to the specified instantaneous shutdown time, they will be protected against the impact of the water hammer pressure and the turbine shaft overspeed. Thus, they will be operated with less risk.
AtıfScopus9WoS8OpenAlex8İncele - MakaleAçık Erişim2018Scopus SJRQ2Investigations of dark, bright, combined dark-bright optical and other soliton solutions in the complex cubic nonlinear Schrödinger equation with δ-potential
Baskonus, Haci Mehmet; Sulaiman, Tukur Abdulkadir; Bulut, Hasan; Aktürk, Tolga
In this study, using the extended sinh-Gordon equation expansion method, we construct the dark, bright, combined dark-bright optical, singular, combined singular solitons and singular periodic waves solutions to the complex cubic nonlinear Schrödinger equation with δ-potential. The conditions for the existence of the obtained solutions are given. To present the physical feature of the acquired result, the 2D and 3D graphs are plotted under the choice of suitable values of the parameters.
AtıfScopus73OpenAlex76İncele - MakaleYalnız künye2018Scopus SJRQ2Effect of the novel biodegradable copolymer and soil salinity on the growth of corn plant
Torğut, Gülben; Beker Akbulut, Gülcin
Biodegradable and biocompatible poly (1,2-epoxy-3-phenoxy propane)-co-(ε-caprolactone) poly(EPP-co-ε-CL) copolymers were synthesized by ring-opening polymerization method at four different ε-CL ratios. Copolymers were characterized using Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance (1H-NMR), thermogravimetric analysis, and differential scanning calorimetry. To examine their possible applications in agriculture, germination test and growth analyses of corn plants were carried out. For this purpose, corn (Zea mays L. cv. “72 May 80”) was allowed to germinate under suitable conditions. Copolymers, 200 mM salt (NaCl) solution, and both copolymers and salt solution were applied to the plants and compared with the control groups. On the 21st day, all the plants were harvested and were stored at −80°C until analysis. Differences in growth parameters, lipid peroxidation degrees, pigment analysis, and total carbohydrate analysis were tested in order to put forward copolymer and NaCl sensitivity of the corn. Statistical analysis was carried out using the SPSS 17.0 software program and the results were compared with each other. These results showed that the copolymers both have a positive effect on the carbohydrate and malondialdehyde (MDA), a product of lipid peroxidation content as well as the chlorophyll content. Moreover, poly(EPP-co-ε-CL0.88) was more efficient than was the other copolymers in the improvement of the detrimental effects of salinity in increasing chlorophyll, carbohydrate, and MDA content, and growth of corn plants. As a result of the study, it was demonstrated that all of the investigated parameters were affected by the applications of salt and copolymers.
AtıfScopus2WoS2OpenAlex3İncele - MakaleAçık Erişim2019Scopus SJRQ3Optimization of medical waste routing problem: The case of TRB1 region in Turkey
Mete, Suleyman; Serin, Faruk
A fundamental problem concerning medical waste disposal is the evaluation of the real and potential risks arising from waste with the focus on the risk of infection. Therefore, the optimization of medical waste routing from collection to disposal center can minimize the risk of infection. The routing of medical waste considers significant to determine potential routes and select the route with minimum distance. The management of the medical waste is important decision for environmental sustainability and includes the collection, transportation and disposal of these materials. In this paper, a geographic information system (GIS) solution approach is proposed to determine the best location of disposal center. Proposed approach is applied to medical waste transportation between 167 health institutions (collection centers) and predetermined 5 disposal centers through TRB1 region in Turkey, which consist of Malatya, Elazığ, Bingöl and Tunceli provinces. The results of case study are examined and suggestions for future research are provided.
AtıfScopus7OpenAlex7İncele - MakaleYalnız künye2020Scopus SJRQ1In-situ synthesis of 3D printable mono- and Bi-metallic (Cu/Ag) nanoparticles embedded polymeric structures with enhanced electromechanical properties
Aktitiz, İsmail; Varol, Remzi; Akkurt, Nevzat; Saraç, Mehmet Fahri
The interest of additive manufacturing with 3D printing increases day by day, which provides improved mechanical, electrical, magnetic and thermal properties of 3D parts. The production of 3D parts with the stereolithography (SLA) method, which allows it to be produced with high precision, resolution and complex geometries, distinguishes itself from other alternative additive manufacturing methods (FDM. SLS. LOM. LMD etc.). However, studies on the preparation of functional 3D polymer nanocomposites with the SLA method are quite limited. This study aims to produce silver (Ag) and/or copper (Cu) based 3D polymer nanocomposites for enhancing its mechanical strength, thermal stability and electrical conductivity. Mono and bimetallic (Cu/Ag) nanoparticles have been in-situ synthesized by selective irradiation of laser beam method using a commercial SLA device. In this method, metal (Cu/Ag) acrylate containing photocurable resin is not only cured but also leads to thermal decomposition of metal ions into nanoparticles to form functional 3D structures. The mechanical, electrical and thermal properties of polymer nanocomposites are characterized in detail. As a result of the analysis, the nanoparticles, with an average diameter of 25–55 nm, are well dispersed in the polymer matrix without agglomeration. The temperature at which 5% weight loss of Ag and Cu based polymer structures is measured as 179.3 °C while the glass transition temperature is found to be 223.81 °C. Most importantly, the resistance values are significantly decreased from 456.62 GΩ (Gigaohm) to 1.50 GΩ by increasing the amount of Ag addition at 3D polymeric structures. Therefore, this study allows the production of polymer nanocomposites not only in complex structures but also in desired properties especially for electrically conductive materials, capacitors and electronic applications.
AtıfScopus32WoS24OpenAlex33İncele - MakaleYayıncıda açık erişim2019Scopus SJRQ3An integrated best-worst and interval type-2 fuzzy TOPSIS methodology for green supplier selection
Yucesan, Melih; Mete, Suleyman; Serin, Faruk; Celik, Erkan; Gul, Muhammet
Supplier selection is one of the most important multi-criteria decision-making (MCDM) problems for decision-makers in the competitive market. Today's organizations are seeking new ways to reduce the negative effects they have on the environment and to achieve a greener system. Currently, the concept of green supplier selection has gained great importance for its ability to incorporate environmental or green criteria into classical supplier selection practices. Therefore, in this study, a multi-phase MCDM model based on the best-worst method (BWM) and the interval type-2 fuzzy technique for order preference by similarity to ideal solution (IT2F TOPSIS) is proposed. A case study in a plastic injection molding facility in Turkey was carried out to show the applicability of the proposed integrated methodology. The paper offers insights into decision-making, methodology, and managerial implications. Results of the case study are examined and suggestions for future research are provided.
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