Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Gul, Muhammet(27)
- Celik, Erkan(14)
- Mete, Suleyman(10)
- Serin, Faruk(10)
- Yucesan, Melih(10)
- Serdar, Osman(9)
- Mahomoodally, Mohamad Fawzi(7)
- Zengin, Gokhan(7)
- Aslan, Alper(6)
- Onat, Onur(6)
- Topal, Murat(6)
- Yildirim, Numan(6)
- Ak, Gunes(5)
- Akkurt, Nevzat(5)
- Alataş, Mevlüt(5)
- Batan, Nevzat(5)
- Cevik, Mutlu(5)
- Erten, Fusun(5)
- Icier, Filiz(5)
- Yildirim, Nuran Cikcikoglu(5)
- Yön, Burak(5)
- Aksakal, B.(4)
- Angeloni, Simone(4)
- Aslan, N.(4)
- Cakilcioglu, Ugur(4)
- Caprioli, Giovanni(4)
- Erata, Hüseyin(4)
- Etli, Serkan(4)
- Gürler, Nedim(4)
- Ince, Muharrem(4)
- Işık, Erdem(4)
- Kaplan Serin, Emine(4)
- Kizilkoca, Mustafa(4)
- Kutlu, Banu(4)
- Maggi, Filippo(4)
- Orhan, Cemal(4)
- Paksoy, Mehmet Yavuz(4)
- Pıhtılı, Güzin(4)
- Sahin, Kazim(4)
- Sançar, Taylan(4)
Yayınlar
- MakaleYalnız künye2021Scopus SJRQ2Investigation of Microstructural and Mechanical Properties of Different Titanium Alloys for Gamma Radiation Properties and Implant Applications
Taşgın, Yahya
In this study, the advantages and disadvantages of different titanium alloys used as industrial and biomedical implant materials are evaluated within the scope of multiple parameters. This research is supported by simulations and aims to understand how titanium and titanium alloys differ mechanically, micro-structurally and in terms of radioactivity. The matrix material of the eight samples used in this research is titanium. The effects of different elements such as Al, V, Sn, Ni, Pb, Mo, Cr, Zr, Fe, Nb, Co on titanium have been examined, the results are compared by considering multiple parameters, and the superior properties of the prominent alloys are highlighted. As a result of the mechanical and electrical tests performed on the alloys, it is obvious that the titanium alloy consisting of Mo and Nb has the highest Brinell hardness, elastic modulus, tensile strength and electrical conductivity parameters compared to other alloys examined within the scope of this research. In the metallographic studies and analyses on samples made up of different alloys, different structures and images emerge for each alloy. These elements rapidly lower the solidification temperature of the material, allowing the β phase to be formed. It has been observed that the two-phase situation has positive effects on the material. On the other hand, the results of gamma ray attenuation tests reveal that Mo and Nb, which make up the alloy, have superior performance compared to other alloy samples due to their high atomic number. Graphical abstract: [Figure not available: see fulltext.]
AtıfScopus8WoS7OpenAlex11
İncele - Kitap BölümüYalnız künye2021Fine–kinney-based occupational risk assessment using hexagonal fuzzy multimoora
Gul, Muhammet; Mete, Suleyman; Serin, Faruk; Celik, Erkan
Hexagonal fuzzy numbers (HFNs) can be used as a proficient logic to simplify understanding of ambiguity information. HFNs present the usual information in a comprehensive way and also the ambiguity section can be exemplified in a reasonable way. In this chapter, we proposed an improved Fine–Kinney occupational risk assessment approach using a well-known MCDM method Multi-Objective Optimization by Ratio Analysis (MULTIMOORA) using hexagonal fuzzy numbers. Since the mere MULTIMOORA has failed to handle uncertainty and vague information which usually exist in real world problems, we follow integration of HFNs and MULTIMOORA (HFMULTIMOORA). To show the applicability of the novel approach, a case study of risk assessment of a raw mill in cement plant was provided. Comparative analysis with using two aggregation tools as reciprocal rank method and dominance theory are carried out. Finally, the Python implementation of the proposed approach is implemented to be effective for those concerned in the future.
AtıfScopus7OpenAlex5İncele - MakaleYalnız künye2021Scopus SJRQ1Numerical simulation of temperature histories of frozen minced meat having different fat contents during ohmic thawing
Cevik, Mutlu; Icier, Filiz
The ohmic thawing (OT) of minced meat sample was mathematically modelled using different numerical methods (Finite Difference-FD and Finite Volume-FV) for different process conditions (voltage gradients of 10, 13 and 16 V/cm and fat contents of meat sample as 2%, 10% and 18%). FD method was successful to predict the temperature changes for both heating and phase change regions. FV method was performed by using two different heat generation functions; depending on process time (UDF-1) or the center temperature (UDF-2). The description of the change of heat generation term depending on process time (UDF-1) in the ANSYS module was more successful with the experimental data compared to the description of the change of heat generation term depending the center temperature (UDF-2). Although FV model is more complex than FD model it can be applied for simulation of detailed temperature distributions. On the other hand, FD model can be applied for practical predictions of temperature histories for center temperatures in simple geometries. It is thought that the simulation of OT performed at different conditions with the FD and the FV methods would contribute valuable data in the design of household ohmic thawing/cooking systems for solid food materials.
AtıfScopus25WoS21OpenAlex21İncele - MakaleAçık Erişim2021Scopus SJRQ2Exposure to copper and risk assessment for human health via consumption of alcoholic beverages
Ince, Muharrem; Kaplan Ince, Olcay; Onal, Ali
Present study was performed using a Box–Behnken Design (BBD) combined with a response surface methodology (RSM). The ultimate goal of this research was to apply BBD for modeling of copper (Cu2+) ions from alcoholic beverages and evaluate health risk assessment of Cu2+ via consumption of alcoholic beverages. The importance of independent paramaters and their interactions were examined using analysis of variance (ANOVA). Natural clay was investigated to remove Cu2+ ions from some alcoholic beverage samples including beer and wine. X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDS) analysis were used for adsorbent characterization. Same analyzes were applied for Cu2+ loaded clay. In addition, experimental studies showed that Freundlich isotherm was better than Langmuir isotherm. Finally, optimized method was applied to alcoholic beverages. Besides target hazard quotients (THQ), estimated daily intake (EDI) values were calculated, to assess a health risk resulting from these alcoholic beverages regular consumption. The EDI values of Cu (µg/day/person) through consumption of investigated drinks were less than the recommended dietary allowance values. Also, the THQ values of Cu2+ were less than 1. According to estimated target hazard, it can be said no long life health concerns of Cu2+ is associated with the consumption of studied drinks. Obtained results were compared with the data from literature and levels set by regulatory authorities, it can be clearly stated that the consumption of mentioned alcoholic beverages do not pose a toxicological risk.
AtıfScopus14WoS10OpenAlex11
İncele - MakaleYalnız künye2021Scopus SJRQ1Sustainable supplier evaluation and transportation planning in multi-level supply chain networks using multi-attribute- and multi-objective decision making
Lo, Huai-Wei; Liaw, Ching-Fang; Gul, Muhammet; Lin, Kuan-Yu
Supplier selection and transportation planning are essential tasks in managing supply chain networks (SCNs). The choice of a supplier has a significant influence on the transportation planning of SCNs, as the transportation routes will change. A limited number of studies in the literature have addressed the supplier selection and transportation planning issues simultaneously. This study proposes a two-stage multi-criteria decision-making (MCDM) approach for sustainable supplier evaluation and transportation planning in multi-level SCNs. Initially, a supplier evaluation framework is proposed using the modified indifference threshold-based attribute ratio analysis (ITARA) and the performance calculation technique of the integrated multiple multi-attribute decision-making (PCIM-MADM) to determine the supplier's performance index. Subsequently, a multi-level SCN model is established, and the sustainable supplier selection and transportation planning problem is solved by the fuzzy multi-objective linear programming (FMOLP) method. A set of real-world data provided by a smart audio manufacturing company has been used to demonstrate the proposed approach. Decision-makers understand the importance of criteria through the weights constructed by the modified ITARA. Moreover, the results of the PCIM-MADM can effectively determine the supplier's ranking and provide improving strategies for underperforming suppliers. The augmented max–min technique of the FMOLP can produce a single optimal solution of the transportation allocation. The results show that our approach can effectively evaluate sustainable supplier performance and optimize transportation planning in SCNs.
AtıfScopus67WoS56OpenAlex64İncele - MakaleYalnız künye2021Scopus SJRQ2Effect of roof and ceiling configuration on energy performance of a metamaterial-based cool roof for low-rise office building in China
Tang, Saihong; Akkurt, Nevzat; Zhang, Kai; Chen, Lufang; Ma, Mingquan
Cool roofs with higher solar reflectance and emittance can effectively reduce building energy consumption. However, it is still limited to use at night on account of the development of roof materials during the past decades. The newly proposed metamaterial-based cool roof (MCR) greatly improves the possibility of the radiative cooling in the daytime. To study the influence of MCR on the energy consumption for the office building, a small single-floor office was adopted to analyse the cooling performance of MCR by using EnergyPlus. In this study, the optimization analysis was conducted based on the proposed dimensionless thermal resistance (θRTR) and roof pitch (Δ). Then the annual electricity saving potential of the office building with MCR was evaluated in details based on the selected cities from all five climate zones in China. The results show that more annual electricity saving can be achieved under the optimized values of θR7 = 1.53 and Δ = 20°. Furthermore, more than 15.7% of annual cooling electricity saving can be achieved while the optimized θRTR and Δ are applied.
AtıfScopus13WoS12OpenAlex15İncele - MakaleAçık Erişim2021Scopus SJRQ3On complex Sasakian manifolds
Turgut Vanlı, Aysel; Ünal, İnan; Avcu, Keziban
In this article, we study a class of normal complex contact metric manifold called a complex Sasakian manifolds. This kind of manifolds have a globally defined complex contact form and normal complex contact structure. We define a complex Sasakian manifold by considering the real case and we present general properties. Also, we obtain some useful curvature relations. Finally, we examine flatness conditions for general curvature tensor B.
AtıfScopus3OpenAlex2İncele - MakaleYalnız künye2021DISSEMINATION OF HEAVY METAL CONTAMINATION IN SURFACE SEDIMENTS OF BATLAMA STREAM, GIRESUN, TURKEY
Ustaoğlu, Fikret; Kutlu, Banu; Tepe, Yalçın; Aydin, Handan
The aim of this study is to detect the heavy metal contamination in the sediment of Batlama Stream and to evaluate the anthropogenic effect. Field studies were seasonally carried out in 3 stations between June 2014 and July 2015. In the sampling studies carried out in Batlama Stream, contamination factor (CF), enrichment factor (EF), potential ecological risk factor (Eri), lowest effect level (LEL), geoaccumulation index (Igeo) contamination indicators were used in order to evaluate sediment contamination. In Batlama Stream, average heavy metal level of three stations was detected in mg/dry kg in the sediment as Cr 7.08, Mn 63.62, Fe 858.04, Co 5.47, Ni 4.99, Cu 20.61, Zn 49.60, Cd 0.09, and Pb 20.68. Elements which the sediment has most are Fe, Mn, and Zn. According to EF, Pb was detected as an enriching element. Eri Pb is in the low risk group. In LEL value, the highest Pb average was found as 31. According to Igeo values, Pb is a moderate contaminant. This metal has anthropogenic sources and it is caused by domestic, agricultural, and waste waters. In the elements analysed in Batlama Stream sediment (apart from Pb), it is indicated that it is generally a clean stream and considered reference stream.
AtıfScopus3İncele - MakaleAçık Erişim2021Scopus SJRQ1Evaluation of non-carcinogenic health risks of thallium in grapevine exposed to mine waters of an abandoned mining region in Turkey
Topal, Murat; Arslan Topal, E. Işıl; Öbek, Erdal
In this study, non-carcinogenic health risks of thallium in grapevine exposed to mine waters of an abandoned mining region in Turkey were evaluated. The values of thallium were investigated in leaves, stems, and roots. Translocation factors (TF) and bioaccumulation concentration factors (BCF) were determined. The maximum thallium value in grapevines (root) was 2.34 ± 0.12 mg/kg. Thallium values in grapevine were stem < leaf < root. The bioconcentration value calculated in our study is higher than 1 showing thallium bioaccumulation from the mine water to grapevines. Translocation factor value is calculated as 1.20. The high total estimated daily exposure dose (TED) in grapevines was determined as 1.10E-02 mg/kg day for children. TEDs values in grapevines were observed as male < female < children, respectively. The maximum HQ risk value for male was observed as 1060 for children. The non-carcinogenic risk values were children > female > male. Hazard index values of thallium in grapevines were ingestion < dietary. As a result, hazard and total hazard index values were > 1 for thallium in grapevines. Therefore, there are non-carcinogenic health risks of thallium in grapevine exposed to mine waters of an abandoned mining region.
AtıfScopus3WoS1OpenAlex2İncele - MakaleYalnız künye2021Scopus SJRQ2Two Medicinal Plants (Alkanna trichophila and Convolvulus galaticus) from Turkey: Chemical Characterization and Biological Perspectives
Mahomoodally, Mohamad Fawzi; Zengin, Gokhan; Sinan, Kouadio Ibrahime; Ak, Gunes; Sadeer, Nabeelah Bibi; Angeloni, Simone; Mustafa, Ahmed M.; Caprioli, Giovanni; Maggi, Filippo; Cakilcioglu, Ugur
The aim of the present study was to quantify selected phenolic compounds, determine antioxidant activity and enzyme inhibitory effects of the aerial parts of Alkanna trichophylla Hub.-Mor. (A. trichophylla) and Convolvulus galaticus Rost.ex Choisy (C. galaticus) extracts prepared by homogenizer-assisted extraction (HAE), maceration (MAC) and infusion techniques. This is the first time such study has been designed to validate the phytochemical composition and bioactivity of these plants. Multivariate analysis was conducted on collected data. Rutin and caffeoylquinic acid derivatives were the most significant compounds in A. trichophylla and C. galaticus, respectively. The highest antioxidant activity of A. trichophylla was mostly exhibited by HAE/methanolic extracts as determined by DPPH, ABTS, FRAP (51.39, 112.70 and 145.73 mg TE/g, respectively) and phosphomolybdenum (2.05 mmol TE/g) assays. However, significant antioxidant activities varied within the extracts of C. galaticus. HAE/methanolic extract of A. trichophylla significantly depressed AChE (2.70 mg GALAE/g), BChE (5.53 mg GALAE/g) and tyrosinase (26.34 mg KAE/g) activities and that of C. galaticus inhibited AChE (2.04 mg GALAE/g), tyrosinase (31.25 mg KAE/g) and α-amylase (0.53 mmol ACAE/g) activities significantly. We concluded that HAE was the most efficient extraction technique as high yield of compounds and promising bioactivities were recorded from extracts prepared. Multivariate analysis showed that types of solvents influenced recovery of compounds and biological activities. This research study can be used as one methodological starting point for further investigation on these plants as all results are clearly promising and open the door to further research challenges such as cytotoxicity evaluation, molecular docking analysis, and more screening of pharmacological actions.
AtıfScopus12OpenAlex10İncele - MakaleAçık Erişim2021Scopus SJRQ3Ultrasonic assisted turning of AISI 52100 steel using nanoparticle-MQL method
Aǧar, Salih; Tosun, Nihat
High cutting force and high cutting tool-chip interface temperature occur during machining of high strength materials like AISI 52100 by using conventional turning method and this makes to the difficult machining operation. Besides, in conventional turning (CT) of these materials, which has high abrasion resistance and hardness properties, an additional process such as grinding is required to achieve the desired surface quality. Ultrasonic assisted turning (UAT) method has been widely used in the machining industry in recent years, as it exhibits better surface quality, lower cutting forces, and cutting temperature than the CT method. This paper focused on experimentally and statistically determining the effects of different cutting parameters and cooling conditions (dry and minimum quantity lubrication-MQL) on surface roughness, workpiece surface texture, tangential direction cutting force, and cutting tool-workpiece interface temperature in the machining of AISI 52100 material by using UAT and CT methods. The experimental results revealed that significant improvements determined in the cutting forces and the surface roughness occurred in UAT compared to CT in all the cooling conditions. However, the increasing cutting speeds caused to observe higher interface temperature values in dry turning by the UAT method. Variance Analysis (ANOVA) was carried out to determine the significance grade of independent variables on dependent variables. According to ANOVA results, while the cutting speed is the most important factor on the surface roughness and the cutting zone temperature, and the cooling method is the most important factor on the cutting force. The effects of turning methods on corresponding surface topography, including surface defects, were evaluated. It is determined that in the surface topography analysis, feed marks are the main texture of the workpiece in the CT method while micro-level indentations and protrusions occurred on the workpiece surface in the UAT method.
AtıfScopus14WoS12OpenAlex14İncele - MakaleYalnız künye2021Scopus SJRQ1Production of Pectin from Lemon Peel Powder Using Ohmic Heating-Assisted Extraction Process
Çilingir, Seda; Goksu, Ali; Sabanci, Serdal
The ohmic heating process is known as homogeneous, efficient, and rapid heating. In the present study, it was aimed to analyze the extraction of pectin from lemon peel using ohmic heating, to evaluate the specific pectin production coefficient (SPPC, mg/kJ) and compared it with traditional pectin production (TPP). The extraction process was carried out at 3 different temperatures (70–90 °C), 3 different solid:liquid ratios (1:30, 1:40, 1:50 g/ml), 3 different extraction holding times (0–30 min), and a constant pH (pH 2 that adjusted with citric acid). From the results, extraction conditions affected the pectin yield. As the temperature and extraction holding time increased, the pectin yields increased. In general, the 30-min pectin yields of the ohmic heating-assisted extraction (OHAE) process were similar to the pectin yields obtained from the TPP under the same conditions. Performance evaluation of pectin production was made for 90 °C, and energy efficiency was found to be over 69% for 3 different solid to liquid ratios. It has been stated that as an alternative to the TPP method, the OHAE process can be applied.
AtıfScopus50WoS44OpenAlex53İncele - MakaleAçık Erişim2021Scopus SJRQ4Electrochemical Corrosion and Metal Ion Release Protective Efficiency of the Multilayer TaN Coatings on CoCrMo Biomedical Alloy
Aslan, Ali Kemal; Bahçe, Erkan; Güler, Mehmet Sami
CoCrMo alloy is widely used in artificial orthopedic joint applications due to its high mechanical properties. But, high levels of the metal ion release from alloy surfaces cause variable toxic and allergic effects on the patient in vivo use. This case restricts the lifetime of the implant and results in the failure of the artificial joint. In order to enhance the corrosion resistance and to decrease the metal ion release, alloy surface was multilayer-coated by closed field unbalanced magnetron system. The protective efficiency of the coatings was determined by potentiodynamic polarization tests and static immersion tests were performed for 45, 60 and 90 days in the simulated body fluid in order to understand the effect of the coatings on the metal ion release. The metal ion concentrations in the simulated body fluids were determined by using inductively coupled plasma mass spectrometry device. The electrochemical corrosion results showed that the multilayer coatings provided 93 % protective efficiency in terms of corrosion resistance. Multilayer coatings decreased the metal ions release levels significantly, especially Co leaking was decreased approximately 52 times compared to uncoated samples.
AtıfScopus2WoS3OpenAlex1İncele - MakaleAçık Erişim2021Scopus SJRQ1An integrated interval type 2 fuzzy AHP and COPRAS-G methodologies for supplier selection in the era of Industry 4.0
Kayapinar Kaya, Sema; Aycin, Ejder
Supply chain has a very extensive and dynamic structure that incorporates new business models, new customer expectations, market searches and technological developments. With the introduction of Industry 4.0 into supply chain, a rapid and intensive process of digitalization begins to transform every step of supply chain. Supply chain selection is one of the essential decisions in reducing the supply chain cost and improving overall quality of product and services. With the implication of digital technologies and Industry 4.0 on supply chain, the supplier selection process has been significantly changed during the recent years. Companies are willing to need new requirements for their own suppliers in accordance with Industry 4.0 implementations and technologies. This paper aims to identify key criteria to Industry 4.0 technologies and evaluate them to select the right suppliers selection in the era of Industry 4.0. Within the scope of this study attempts to develop an integrated interval type 2 fuzzy AHP and GOPRAS-G methodology to select the appropriate supplier in the face of Industry 4.0 implementations. For this purpose, interval type 2 fuzzy AHP was employed to weight the supplier evaluation criteria and then, Gray COPRAS method has been applied to prioritize suppliers. This paper is to provide practitioners and researchers with insight into how Industry 4.0 strategies influence on supplier selection.
AtıfScopus63WoS51İncele - MakaleYalnız künye2021Scopus SJRQ3Glyphosate disrupts sperm quality and induced DNA damage of rainbow trout (Oncorhynchus mykiss) sperm
Akça, Ayşe; Kocabaş, Mehmet; Kutluyer, Filiz
As a widespread pollutant, glyphosate (GLY) adversely affects the aquatic environment and can impair the reproductive ability and functions of fish. The purpose of the current study was to assess in vitro effect of GLY on rainbow trout (Oncorhynchus mykiss) sperm cells. The sperm cells were exposed to different GLY concentrations (2.5, 5, 10 mg/L). Sperm motility parameters were analyzed with computer assisted sperm analysis. DNA fragmentation (%) was measured by the comet assay using fluorescence microscopy. With increased GLY concentration, sperm motility and duration decreased after exposure. DNA fragmentation (% DNA in tail) in sperm cells was higher in treatments containing GLY than control (p < 0.05). Consequently, sperm cells are sensitive to low doses of GLY, and this can negatively affect natural populations.
AtıfScopus8WoS4OpenAlex5İncele - MakaleAçık Erişim2021Scopus SJRQ2Comparative Toxicity of Alpha and Gamma Iron Oxide Nanoparticles in Rainbow Trout: Histopathology, Hematology, Accumulation, and Oxidative Stress
Gürkan, Mert; Gürkan, Selin Ertürk; Yılmaz, Sevdan; Ateş, Mehmet
In this study, alpha and gamma iron oxide nanoparticles, characterizations, toxic effects after being exposed to rainbow trout (Oncorhynchus mykiss) at 0, 1, 10 and 25 mg/L concentrations for 10 days, and then 10-day recovery period without any nanoparticle exposure were examined for histopathological (kidney, liver and gill), hematological, iron accumulation and potential for oxidative stress (TBARS and GSH). Histopathological damages significant at the exposure of increasing concentrations of both nanoparticles (increase in melanomacrophage aggregations, epithelial tissue deformations, cytoplasmic vacuolizations, fatty changes, necrosis, pyknosis, hyperplasia, hypertrophy, lamellar fusions, capillary dilatations). Gamma nanoparticles were determined to accumulate more than the alpha nanoparticles. The most Fe accumulation was detected in the liver. The findings of oxidative stress parameters showed that both nanoparticles have the potential to generate oxidative stress. It was concluded that the exposure of alpha and gamma nanoparticles at specified concentrations and durations had a toxic effect on rainbow trout and the toxicity of these nanoparticles was similar.
AtıfScopus18WoS12OpenAlex16İncele - MakaleAçık Erişim2021Scopus SJRQ2Electrical investigation on Eu+3- doped copolymer composite system and conventional kinetic analysis
Pıhtılı, Güzin; Biryan, Fatih
Poly(maleic anhydride-co-benzyl methacrylate) copolymer was prepared by using free radical polymerization (FRP) method at 70 °C. The structural characterization of the polymer was accomplished FT-IR, 1H and 13C NMR spectroscopic techniques. P(MA-co-BMA)/ EuCl3 composites were prepared rate of 2%, 5% and 10% (wt/wt). The thermal behavior of pure copolymer was investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Thermal decomposition kinetics of poly(MA-co-BMA) carried out from Flynn–Wall–Ozawa method via TG curves for calculated apparent activation energies. According to FWO; the activation energy (Ea) was estimated as; 185.61 kJ/mol. Dielectric and electrical properties of copolymer/composite systems were investigated against frequency (range from 100 Hz to 20 kHz) at room temperature by using an impedance analyzer. The effect of EuCl3 concentration on dielectric constant, dielectric loss factors, ac conductivity, susceptance (B) and impedance (Z) was investigated. A remarkable increase was observed in dielectric and AC electrical properties were observed with the addition of Eu+3 to the polymer matrix. The B and Z parameters of poly(MA-co-BMA) and composites were investigated depending on frequency at room temperature based on the alternating current (AC).
AtıfScopus2WoS2OpenAlex2İncele - MakaleAçık Erişim2021Influence of particle size, additive ratio and chemical structure of zinc borate on mechanical properties of poly(vinyl chloride)
İpek, Yeliz
Zinc borate (ZB) is a flame retardant and smoke supressant compound of boron. It is widely used to achieve flame resistant polymer composites. Poly(Vinyl Chloride) (PVC) is one of the commercially important polymers that is mostly used for cable insulating, windows, doors, pipes, floorings and toys etc.. On the other hand, PVC releases toxic gases during fire as decomposition products. Zinc borate addition is thought to be a solution for this problem. However, this solution leads a new problem. Zinc borate effects the mechanical properties of the PVC. In the present study, to optimize the contribution of zinc borate, with different formulations (2ZnO·3B2 O3·3.5H2 O and 4ZnO·B2 O3·H2 O), with different additive ratios (1% and 5% by weight) and different particle sizes (nano-sized and micro-sized) were added to the PVC structure and the mechanical and thermomechanical properties of each composite were investigated. Mechanical properties of composites were determined by tensile test, impact test, hardness test while thermomechanical behaviours were detected with dynamic mechanical analysis (DMA). In the perspective of mechanical strength of PVC-ZB composite, additive ratio of ZB was more effective than particle size and chemical formulation of ZB. The additive ratio more than 5% by weight can negatively affect the mechanical strength and quality of the PVC-ZB composite.
AtıfScopus2OpenAlex2
İncele - MakaleAçık Erişim2021Scopus SJRQ2Hospital Preparedness Assessment against COVID-19 Pandemic: A Case Study in Turkish Tertiary Healthcare Services
Gul, Muhammet; Yucesan, Melih
Hospitals play a critical role in providing essential health services to people in the healthcare system. Healthcare systems around the world have faced some issues in responding to patients with various disease severity levels. Nowadays, the world as a whole is combating a pandemic called COVID-19. This pandemic causes an increase in the disease spread with fluctuated patient demand that may affect the hospitals' capacity and overall functioning and risks rising based on hospital site, medical staff, patient, and healthcare process. To deal with the challenges of the COVID-19 pandemic, hospitals must have completed their preparations before these events occur. Therefore, this study proposes an integrated approach based on the decision-making concept with interval-valued spherical fuzzy sets (IVSFSs) to the hospital preparedness assessment problem. A technique for order preference by similarity to ideal solution (TOPSIS) extended with IVSFSs is used to rank hospitals from Turkish tertiary healthcare services. A checklist reported by the World Health Organization (WHO) is adapted to conform to Turkey's COVID-19 pandemic management. Ninety-nine subcomponents of the adapted checklist under ten components are weighted by interval-valued spherical weighted arithmetic mean (IVSWAM) operator. The hospitals in the problem are then ranked concerning these weighted subcomponents. With the proposed approach, a COVID-19 pandemic preparedness index is determined for the observed hospitals. In addition, a separate index based on each main component (component-based ranking) is determined. These indexes are vital indicators in determining in which aspects hospitals are ready and in what aspects hospitals are not prepared for pandemics. The proposed approach can be adaptable and applied by national policymakers in assessing all hospitals of the country against the COVID-19 pandemic.
AtıfScopus45WoS33OpenAlex44İncele - MakaleAçık Erişim2021Scopus SJRQ1Carbon and water balance of an afforested shallow drained peatland in Iceland
Bjarnadottir, Brynhildur; Aslan Sungur, Guler; Sigurdsson, Bjarni D.; Kjartansson, Bjarki T.; Oskarsson, Hlynur; Oddsdottir, Edda S.; Gunnarsdottir, Gunnhildur E.; Black, Andrew
Drainage of peatlands increases the depth of the oxic peat layer and can turn them into a carbon (C) source to the atmosphere. Afforestation of drained peatlands could help to reverse this process since the trees may enhance C sequestration. We followed the C and water dynamics of an afforested drained peatland in S-Iceland during a 2 year period, during which the Black Cottonwood (Populus balsamifera ssp. trichocarpa) plantation was 23–25 year old. Net ecosystem exchange (NEE) of carbon dioxide (CO2) was measured with the eddy covariance method and C pools of trees and ground vegetation were measured using the stock change method. Lateral losses of dissolved and particulated organic C (DOC, POC) were estimated from weekly water-runoff samples. Unexpectedly, the afforested drained peatland was a strong sink of carbon during the two years, with an average NEE value of 714 g C m−2 yr−1. Only 0.5% of the total NEE was lost through lateral DOC and POC transport, leaving 710 g C m−2 yr−1 as the total net ecosystem production (NEP). Ca. 91% of the observed NEP could be explained by the annual biomass increment of the Black Cottonwood trees and 1.3% by the ground vegetation. This means that the remaining 7.5% of the total NEP most likely accumulated in peat soil and litter, contributing to the soil C stocks. The dormant-season CO2 emissions were unexpectedly low, which was explained by a high groundwater level at this drained site outside the ca. 5 months of the active growing season. On average, 66% of the annual measured precipitation was estimated to have evaporated back to the atmosphere. This left 416 mm for potential runoff, which was somewhat lower value than the measured runoff (662 mm). These results indicate that during the age span of ca. 20–25 years, afforestation was a valid method to reverse the expected negative C-balance of this drained grassland pasture in Iceland. Although the site is currently a soil C sink, simulation studies with process models are needed to test whether such sites could remain C sinks when managed for forestry over several tree-stand rotations.
AtıfScopus18OpenAlex21İncele