Yazarlar
- Tanyol, Mehtap(22)
- Yildirim, Numan(17)
- Karataş, Mehmet(14)
- Erguven, Gokhan Onder(13)
- Topal, Murat(13)
- Ince, Muharrem(12)
- Yildirim, Nuran Cikcikoglu(10)
- Kismet, Yilmaz(9)
- Öbek, Erdal(8)
- Arslan Topal, E. Işıl(7)
- Etli, Serkan(7)
- Goksu, Ali(7)
- Gul, Muhammet(7)
- Gülmez, Nihan(7)
- Ogedey, Aysenur(7)
- Uysal, Turan(7)
- Yonten, Vahap(7)
- Gürler, Nedim(6)
- Kaya, Sema Kayapinar(6)
- Sabanci, Serdal(6)
- Serdar, Osman(6)
- Yön, Merve Şahin(6)
- Alp, Hevidar(5)
- Aydoğmuş, Ercan(5)
- Benli, Ahmet(5)
- Cemalgil, Selim(5)
- Erdemoğlu, Murat(5)
- Erust, Ceren(5)
- Ince, Olcay Kaplan(5)
- Oguz, Ensar(5)
- Torğut, Gülben(5)
- Yilmaz, Mehmet(5)
- Yucesan, Melih(5)
- Celik, Erkan(4)
- Demir, Veysel(4)
- Dener, Murat(4)
- Doğan, Akar(4)
- Fırat, Tülay(4)
- Pekdemir, Mustafa Ersin(4)
- Tanaydin, Mehmet Kayra(4)
Yayınlar
- MakaleYalnız künye2024Scopus SJRQ1Optimization of Pectin Extraction from Lemon Peel Powder by Ohmic Heating Using Full Factorial Design
Çilingir, Seda; Duran, Gülseven; Gökyildiz, Beritan; Goksu, Ali; Sabanci, Serdal; Cevik, Mutlu
Ohmic heating-assisted extraction has emerged as an effective method preferred in recent years. This extraction method is affected by experimental factors such as temperature, process time, and voltage gradient. The present study aimed to optimize the pectin extraction process from lemon peel powder samples by the ohmic heating-assisted extraction method. In this study, the effects of 3 different voltage gradients (7, 9, and 11 V/cm), 3 different solid to liquid ratios (1:20 g/mL, 1:40 g/mL, and 1:60 g/mL), and 3 different holding times (0, 60, and 120 min) and their interactions were investigated to determine the optimum extraction condition at constant temperature (80 °C) and pH = 1 sulfuric acid solution. The factors examined in the optimization procedure were pectin yield, power consumption, and energy efficiency. The optimum conditions were found to be 11 V/cm voltage gradient, 1:60 g/mL solid to liquid ratio, and 120-min holding time with a desirability value of 0.778. The results of this study could give important information about the design of industrial scale ohmic heating units, especially from different food wastes in industrial pectin production.
AtıfScopus7WoS7OpenAlex5
İncele - MakaleAçık Erişim2023An Optimization Approach for A Biogas Supply Chain using Goal Programming and Mixed Integer Linear Programming
Derse, Onur; Göçmen, Elifcan
Environmental concerns prompt the world for a transition to renewable energy sources from fossil energy. Reducing the dependency on non-renewable sources of energy is prerequisite for the sustainable world and less environmental pollution. Biogas energy, which is one of the most important renewable energy sources, is produced by burning organic wastes and can be used in many different fields. In this study, a two-stage approach is undertaken to optimize a biogas supply chain design by incorporating of 30 districts in Izmir. In the first stage, the selection of the most suitable biogas plants is considered by the goal programming approach, which is of great importance to decide the optimal location with high energy potential. The most suitable sites for the biogas plants are obtained as Konak and Narlıdere districts. In the second stage, the location problem of the biogas vehicle charging stations (BVS) for biogas vehicles is handled considering the results of the first stage using mixed integer linear programming (MILP) approach. Computational results demonstrate that it would be more appropriate to establish BVS in 12 districts of İzmir. The model and solution approach are pioneering for supply chain problems and an efficient tool for renewable energy plans.
AtıfOpenAlex3
İncele - MakaleAçık Erişim2023Saman Takviyeli Yüksek Yoğunluklu Polietilen Kompozitlerin Mekanik Özellikleri ve Su Emme Kapasitelerindeki Değişimlerin İncelenmesi
Kismet, Yilmaz; Doğan, Akar
Bu çalışmada, poliolefinler grubunun önemli bir üyesi olan yüksek yoğunluklu polietilen ile saman bitkisinden oluşan kompozitler üretilmiştir. Kompozit malzemeler, yüksek yoğunluklu polietilen içerisine saman takviyesi ağırlıkça %5, %10 ve %20 oranlarında takviye edilerek üretilmiştir. Bu karışımlar öncelikle mekanik olarak karıştırılmış daha sonra homojen bir karışım oluşturabilmek için 160 ila 180 oC sıcaklıklar arasında ekstrüzyondan geçirilmiştir. Ekstrüzyon sonrası elde edilen karışım önce soğutma havuzunda soğutulmuş daha sonra kırıcıdan geçirilerek granül hale getirilmiştir. Elde edilen bu granüller plastik enjeksiyon makinasında kalıplara basılarak standart test numuneleri üretilmiştir. Üretilen kompozitlerin takviye malzemesi oranı ile mekanik özelliklerindeki ve su emme kapasitelerindeki değişimler incelenmiş ve sonuçlar grafik ve tablo olarak verilmiştir. Kompozit malzemlerin çekme mukavemtleri, üç nokta eğilme mukavemetleri ve izod darbe dayanımları analiz edilmişdir. Malzemelerin çekme ve izod darbe dayanımları azalırken, eğilme mukavemetinde iyileşme gözlenmiştir.
AtıfOpenAlex1İncele - Derleme MakaleAçık Erişim2023Türkiye’de Doğal Boya Kullanan Tekstil İşletmeleri ve Bitki Atıkları ile Sürdürülebilir Bir Yaklaşım Önerisi
Ayvaz, Kartal Murat; Teker, Menekse Suzan
Sürdürülebilirlik; tekstil sektörünün hammadde temini, iplik eğirme, dokuma, örme, terbiye, boya/baskı ve konfeksiyon bileşenlerinin tüm süreçleriyle ilgili bir kavramdır. Sürdürülebilir bir yaklaşım insan sağlığı ve ekosistem açısından sentetik madde kullanımının en aza indirilmesi, hızlı tüketim anlayışından vazgeçilmesi, sınırlı ve kıt kaynakların iktisatlı kullanılmasını gerektirmektedir. Sentetik boyaların üretimi ve kullanımı sonrasında oluşan atıkların çevre ve insan sağlığı açısından yarattığı sorunlar birçok akademik çalışma ile ortaya konmuştur. Doğal boyaların bu noktada ön plana çıktığı bilinmektedir. Türkiye’de tekstil işletmelerinde doğal boya kullanımına daha gerçekçi ve çözüm odaklı yaklaşabilmek adına Türkiye’de doğal boyalı giysi ve aksesuar üretimi yapan tekstil işletmeleri incelenmiştir. İşletmelerin tekstil ve çevre konusundaki bakış açıları, ürünleri ve kullandıkları doğal boya kaynaklarına yer verilmiştir. Hammadde kaynaklarının sürdürülebilir bir yaklaşım ile değerlendirilmesi noktasında işletmelerden yalnızca bir tanesinin atık olarak değerlendirilebilecek boyarmadde kaynakları kullandığı görülmüştür. Hem mevcut uygulamalara dair hem de “doğal boyaların tekstil endüstrisinde kullanımı” problemine alandaki akademik çalışmalardan, tartışmalardan, gözlem ve deneylerden hareketle tıbbi ve aromatik bitkilerin uçucu yağı alınmış posaları ile tıp, gıda ve kozmetik sektörlerinde kullanılan bitkilerin atıklarının (posalarının) kullanımına yönelik çalışmalar derlenerek öneriler sunulmuştur.
AtıfOpenAlex5TR Dizin2İncele - MakaleAçık Erişim2023Cu/Zn Oksit İkili Katalizörü Üretmek Amacıyla Malahit Cevherinin NH3/NH4NO3 Liçinde Optimum pH ve NH3 Derişiminin Yanıt Yüzey Yöntemiyle Belirlenmesi
Demirkiran, Nizamettin; Tanaydın, Zümra Bakıcı; Baysar, Ahmet
Bu çalışmada, bir hidrosikarbonat minerali olan malahit ve bir karbonatlı mineral olan simitsonit içeren bakır cevherinin hidrometalurjik yöntemle işlenmesi neticesinde Cu/Zn oksit ikili katalizörü üretilmiştir. Cevherden maksimum oranda bakır ve minimum oranda çinkonun liç çözeltisine geçmesini sağlayacak ancak cevherde bulunan diğer metallerin çözünmesini engelleyecek pH ve çözücü derişiminin optimum değerleri yanıt yüzey yöntemi ile belirlenmiştir. Yanıt yüzey yönteminde elde edilen deneysel bulgulara çoklu regresyon analizi yapılarak bakır ve çinko liç verimleri ile bağımsız değişkenler arasındaki ilişkiyi gösteren ikinci dereceden model denklemler elde edilmiştir. Bakır ve çinko liç verimi üzerine NH3 derişiminin pH’dan daha etkili bir parametre olduğu belirlenmiştir. NH3 ve NH4NO3 derişimleri ile pH için optimum değerler sırasıyla 0,38 M, 0,11 M ve 9,80 olarak bulunmuştur. Optimum koşullarda cevherdeki bakırın %82,3’ünün çinkonun ise %45,1’inin çözeltiye geçtiği belirlenmiştir. Liç sonucunda elde edilen çözeltideki Cu+2 ve Zn+2 iyonları Na2CO3 çözeltisi ile çöktürülmüş ve oluşan katı ürün 350 °C’de 6 saat süreyle kalsine edilerek Cu/Zn oksit ikili katalizörü üretilmiştir. Katalizörün ağırlıkça bakır oksit içeriği yaklaşık %44 ve çinko oksit içeriği %56 olarak tespit edilmiştir.
- MakaleAçık Erişim2023Determination and monitoring of tetracycline and degradation products in livestock slaughterhouse wastewater treatment plant effluent
Topal, Murat; Topal, E.Işıl Arslan; Öbek, Erdal
Aim of our study was the determination and monitoring of tetracycline (TC) and degradation products (DEP) in livestock slaughterhouse wastewater treatment plant (SWWTP) effluent. For this purpose, TC and DEP values in SWWTP were investigated. The concentrations of TC and DEP were monitored for 12 months. TC, 4-epitetracycline (ETC), 4-epianhydrotetracycline (EATC), anhydrotetracycline (ATC), and physicochemical parameters of pH, suspended solids (SS), BOD5, COD, and TP were calculated. The maximum TC concentration was determined as 1.68±0.08 µg/L in March and the minimum TC was 1.08±0.05 µg/L in January. The maximum ETC was 2.93±0.14 µg/L in March and April. The minimum ETC was 1.98±0.1 µg/L in January. EATC was 10.82±0.5 µg/L in September, and minimum EATC value was determined as 9.14±0.4 µg/L in March. The maximum ATC value was 8.62±0.4 µg/L in June and the lowest ATC value was 6.61±0.3 µg/L in September. Concentrations of TC and DEP detected in SWWTP effluent were listed in descending order as EATC> ATC> ETC> TC.
AtıfOpenAlex1İncele - MakaleAçık Erişim2023Reclaim of Wrecked Bi-Te Based Materials In Peltier Modules In Thermopower Properties By Mechanical Milling
Yüzüak, Ercüment; Cetin, Mehmet; Yüzüak, Gizem Durak
We thoroughly evaluated the effects of various treatments on the structural and electrical properties of the two as-cast materials, “Sb-doping Bi-Te (p-type)” and “Se-doping Bi-Te (n-type)” which are frequently present in abandoned Peltier modules. To investigate the thermoelectric properties of Bi2Te3-based materials, waste alloys characterized by electrical conductivity using the hot-end method. Alloys were purified by performing arc melting on a water-cooled copper crucible in a vacuum of at least 10-3 mbar, with five times melting sessions to assure homogeneity. A single and long milling period of 144 hours is applied. After the compressing operation, the resulting discs with nanostructures were annealed for an hour at 600 K under vacuum conditions. The discs' structural properties were characterized using X-ray diffraction (XRD) and their surfaces and stoichiometries were determined using scanning electron microscopy with an energy dispersive feature. The Seebeck coefficient of the nanoparticle formed n-type Bi-Te based sample is -35.3 μV.K-1 and p-type Bi-Te based sample is 100 μV.K-1 (15% of mean error margin). It was found that a notable improvement was attained in comparison to the initial state with the addition of nanoparticles.
- MakaleAçık Erişim2023Pirofillit Cevherinden Alümina Üretimine Zenginleştirme Yöntemlerinin Etkisi
Erdemoğlu, Murat; Uysal, Turan; Aydoğmuş, Ramazan
Bu çalışmada, pirofillit cevherinden alüminyum (Al) kazanımı üzerine farklı zenginleştirme yöntemlerinin etkisi araştırılmıştır. Zenginleştirme yöntemleri pirofillitin doğal hidrofob yapısından dolayı flotasyon yöntemi, kırılganlık farklılığından dolayı ise Aşındırmalı Yıkama (AY) yöntemi kullanılmıştır. Zenginleştirme sonucu konsantre numunelere HCl ile liç işlemi yapılmış, liç sonucu çözeltiye geçen Al miktarları karşılaştırılarak değerlendirilmiştir. Pirofillit cevherinin AY yöntemi ile zenginleştirilmesi sonucu %54.79 verimle %27.44 Al2O3 tenörlü bir konsantre, flotasyon yöntemi ile ise %30.49 verimle %28.05 Al2O3 tenörlü bir konsantre elde edilmiştir. Buna göre zenginleştirme verimi açısından AY yöntemi daha verimli iken liç verimi açısından ise flotasyon yönteminin daha verimli olduğu belirlenmiştir. Tüvenan cevhere göre nihai alümina miktarı ve saflığı birlikte değerlendirildiğinde doğrudan liç ve AY konsantresi değerlerinin birbirine yakın olduğu belirlenmiştir. Sonuç olarak pirofillit cevherinden alümina üretimi için ayrıntılı ekonomik analiz yapılarak uygun yöntemin belirlenmesinin daha doğru olacağı değerlendirilmektedir.
- MakaleAçık Erişim2023Scopus SJRQ3Anthocyanin based sensory pad for determination of chicken meat spoilage
Ipek, Y.; Ertekin, O.
Production and consumption of chicken meat has increased considerably with the increasing world population, and will continue to increase, due to its health benefits and its economic value. Chicken meat is a sensitive food due to its characteristics and microbiological load. Traceability is very important to increase food safety and biosecurity. Freshness indicators are often used to monitor the presence of metabolites produced by microorganisms, mostly functioning through the colour change of the indicator. A developed natural, edible, biodegradable, purple coloured pH sensitive sensory pad was put inside a chicken meat package to observe the chicken meat spoilage with colour change due to pH changes in the meat.
AtıfWoS1OpenAlex1İncele - MakaleAçık Erişim2023Scopus SJRQ1An Integrated Approach for Assessing Suppliers Considering Economic Sustainability Innovation
Ahmadi, Hadi Badri; Pamucar, Dragan; Pourhejazy, Pourya; Kaya, Sema Kayapinar; Liou, James J. H.
Innovation plays a key role for improving the sustainability performance of corporations. A truly sustainable innovative firm needs to take the social, environmental, and economic aspects of sustainable innovation into consideration. However, limited studies have investigated the economic aspect of sustainable innovation, especially in the context of supplier evaluation from emerging economies. To deal with this issue, this manuscript puts forward a criteria decision framework for evaluating economic sustainable innovative suppliers. A new methodology based on fuzzy Full Consistency Method (FFUCOM) and Improved Combinative Distance-based Assessment (ICODAS) is developed and extended using interval rough Dombi-Bonferroni operators. In the developed approach, the FFUCOM is employed to determine the criteria weights, and the ICODAS is responsible for assessing and ranking the suppliers. A case study from the manufacturing sector of an emerging economy is considered for validating the developed framework and decision model. The findings introduce the 'financial resumption of products' as the most critical economic innovation criterion for evaluating suppliers. This article significantly helps decision-makers and practitioners to better comprehend the underpinnings of sustainable innovation economic dimension, particularly when assessing their suppliers. Furthermore, the applicability and validity of the proposed model was confirmed by the results of sensitivity analysis. Findings demonstrated that the proposed method is a solid and useful MCDM framework, and its outputs are precise and acceptable.
AtıfScopus9OpenAlex6İncele - MakaleYalnız künye2023Scopus SJRQ3Green Synthesis and Encapsulation of Superparamagnetic Magnetite for Mercury (II) Removal: Adsorption Isotherms, Adsorption Kinetics, and Thermodynamic Studies
Alp Kavlo, Hevidar; Ince, Muharrem; Kaplan Ince, Olcay; Aydogdu, Burcu; Ozcan, Cemile
Mercury (II) ions have significant ecological impacts. In the current study, magnetized iron oxide (Fe3O4) nanoparticles were green synthesized and encapsulated with alginate (ALG). The nanoparticles were converted into a composite (Fe3O4/ALG). The Fe3O4/ALG beads were used to remove Hg (II) from industrial wastewater. Characterization was performed by X-ray diffraction (XRD), scanning electron microscopy—energy dispersive spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis-differential thermal analysis (TGA-DTA). A central composite design (CCD) approach was performed to define the experimental conditions providing the highest global adsorption efficiency and to optimize the pH, temperature and adsorbent mass. Hg (II) concentrations were determined by flame and electrothermal atomic absorption spectrometry (FAAS and ETAAS). The limits of detection (LOD) and quantification (LOQ) were 1.2 mg L−1 and 3.5 mg L−1 for FAAS and 0.2 µg L−1 and 0.5 µg L−1 for ETAAS, respectively. Additionally, Langmuir, Freundlich, and Temkin isotherm models were employed to determine the adsorption mechanism. The adsorption capacity of Fe3O4/ALG was determined to be 49.18 mg g−1 by the Langmuir model. Kinetic studies revealed that the adsorption of Hg (II) best fitted the pseudo-second order model. The Gibb’s free energy (ΔG°) values showed that the adsorption of Hg (II) on Fe3O4/ALG occurred spontaneously.
AtıfScopus8WoS8OpenAlex10İncele - MakaleAçık Erişim2023Scopus SJRQ3Effect of glass sand used as aggregate on micro-concrete properties; [Učinak recikliranog stakla kao agregata na svojstva mikrobetona]
Etli, Serkan
Micro-concrete (MC) can be defined as a high-performance cement-based material produced using microaggregates and cement in the required proportions. Owing to its high performance, it has the potential to be used in the structural repairs of existing building elements. Within the scope of this study, an evaluation was conducted by creating a usage scenario under which glass, which is a waste product, can be reduced and applied in a way that provides a sufficient MC performance. There are four different binder contents in the mixtures within the scope of the present study, i.e., 570, 580, 599, and 658 kg/m3. From these mixtures, together with the control mixture, 12 %, 27 %, and 50 % microaggregates were replaced with glass sand and 16 different mixtures with a total of 4 different aggregate contents were produced. For the mechanical, physical, and durability tests, 40 × 40 × 160 mm sized prisms and 50 × 50 × 50 mm sized cubes were produced. For the purposes of this research, mechanical tests were carried out on 144 7-, 28- and 56-day old prismatic specimens. In addition, the effects of a freeze-thaw and temperature on the mechanical properties were investigated on 192 prismatic samples. In determination of the durability, physical properties such as the porosity, sorptivity, and specific gravity were tested and determined using cubic samples. The test results show that the replacement of MA with GS has positive effects on all mechanical behaviours of MC.
AtıfScopus7OpenAlex12İncele - MakaleYalnız künye2023Scopus SJRQ2Physicochemical Properties for Food Packaging and Toxicity Behaviors Against Healthy Cells of Environmentally Friendly Biocompatible Starch/Citric Acid/Polyvinyl Alcohol Biocomposite Films
Gürler, Nedim; Paşa, Salih; Erdoğan, Ömer; Cevik, Ozge
The current study focuses on the fabrication, characterization, and cytotoxic effects of polymeric biocomposite films composed of starch, various concentrations of citric acid (3%, 6%, and 9%), and polyvinyl alcohol. The cross-linked corn starch (S)-polyvinyl alcohol (P) biocomposite films are prepared by casting technique using glucose (G) and fructose (F) as plasticizers. The chemical structure of obtained films is characterized by Fourier transform infrared and x-ray diffraction. Physicochemical parameters of the films such as solubility, swelling capacity, and water vapor permeability, optical and mechanical properties are investigated. Furthermore, the cytotoxicity is evaluated to determine the biocompatibility of samples. The physicochemical properties of S-P(Starch-Polyvinyl alcohol) films improve with the addition of citric acid during the esterification reaction. The tensile strength for Starch-Polyvinyl alcohol-Glucose blend composition with 3% citric acid (SPG3) and Starch-Polyvinyl alcohol-Fructose blend composition with 3% citric acid (SFG3) biocomposite films is determined as 10.17 and 8.24 MPa, respectively, compared to 8.16 and 7.94 MPa for without citric acid, respectively. The cell viability values of biocomposite films towards NIH-3T3 and L929 cells are calculated 90% compared to the control group. Thus, it demonstrates that they are also quite biocompatible materials.
AtıfScopus34WoS37OpenAlex37İncele - MakaleYayıncıda açık erişim2023Scopus SJRQ3Potassium chloride recovery from mechanically activated microcline through the chlorination roasting and leaching route
Alyosif, Bahaa; Uysal, Turan; Erdemoğlu, Murat
In this study, effects of mechanical activation in the chlorination roasting and water leaching route known as CaCl2 process and developed for the production of potassium chloride (KCl) from potassium feldspar ores were studied. A microcline containing K-feldspar ore with 10.89% K2O was first intensively dry milled by a planetary ball mill and mixed with calcium chloride (CaCl2) and then roasted at temperatures up to 1000 °C to obtain KCl that will be finally dissolved by the water leaching. Potassium recovery by water leaching increased rapidly up to 800 °C. At higher temperatures, the recovery decreased fast due to the evaporation of KCl. According to the K recovery values per unit energy consumed, the optimum roasting temperature was determined as 750 °C and the milling time was 15 min. It was concluded that intensive milling causes mechanical activation of the microcline to reduce the chlorination roasting temperature, which triggers a rise in the K recovery by the water leaching.
AtıfScopus9WoS8OpenAlex7İncele - MakaleAçık Erişim2023Scopus SJRQ3Bioremediation of herbicide diquat dibromide from aqueous solution with white rot fungus Phanerochaete chrysosporium
Yildirim, Numan; Ciftci, Emine; Erguven, Gokhan Onder; Durmus, Barbaros
In this study, the fungal bioremediation of herbicide diquat dibromide (DD) by white rot fungus Phanerochaete chrysosporium was studied. After bioremediation, the reduction in toxicity of the remediated media was evaluated by Daphnia magna as a model organism. For bioremediation studies, flask-level batch experiments were performed at different DD concentrations (10, 20 and 50 ppm) under static and agitated conditions. The highest reduction rates of chemical oxygen demand and total organic carbon were determined as 85.92 (for 20 ppm DD) and 87.46% (for 10 ppm DD), respectively under agitated conditions. After bioremediation, D. magna bioassay was used for toxicity assessment during 24, 48 and 72-h periods. In current study, it was observed that P. chrysosporium has very effective bioremediation capacity for diquat dibromide. The D. magna bioassay revealed that P. chrysosporium provides effective reduction in toxicity of diquat dibromide.
- Derleme MakaleYalnız künye2023Scopus SJRQ1Hydrometallurgical Roadmaps and Future Strategies for Recovery of Rare Earth Elements
Erust, C.; Karacahan, M.K.; Uysal, T.
Increasing demand for low carbon technologies and renewable energy sources requires our resources and economies to be circular. Many countries agree that the responsible consumption, production, and recycling of rare-earth-containing products is essential as a way to achieve the sustainable development goals also set out in the European Green Deal. Sustainable sourcing is targeted with carefully designed roadmap for cost efficient REE production from end-of-life products (EoLs) in addition to mining activities as providing primary sources. Hydrometallurgical methods, such as roasting, leaching, precipitation, crystallization, solvent extraction, and ion exchange includes fast developing, selective, eco-friendly, and cost-effective technologies especially for the extraction of REEs. This article provides an overview of primary and secondary resources and summarizes presents case scenario of studies carried out on the use of some promising methods, which could serve as an economical means for recovering REEs.
AtıfScopus46WoS46OpenAlex51İncele - MakaleYayıncıda açık erişim2023Scopus SJRQ1Evaluation 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.
AtıfScopus51WoS43OpenAlex55İncele - MakaleYalnız künye2023Scopus SJRQ3Evaluation of social factors within the circular economy concept for European countries
Kaya, Sema Kayapinar; Ayçin, Ejder; Pamucar, Dragan
The circular economy (CE) is a rapidly growing theme, particularly in the European Union (EU), that encourages the responsible and circular use of resources in the field of contributing to long-term development. The environmental and economic magnitude of development are frequently debated in the subject of CE whereas, social aspects have been only rarely and sporadically combined into the CE. Therefore, this study involves a multidisciplinary holistic framework of clustering methods and Multi-Criteria Decision Making (MCDM) for evaluating the CE paradigm in relation to EU countries' social growth. In terms of the social impact of CE strategies, the k-means cluster analysis was used to group the 27 EU members with similar social impact levels. Subsequently, a novel integrated CRITIC (The criteria importance through intercriteria correlation) and MEREC (Method based on the Removal Effects of Criteria) methods were employed for determining the weights of social indicators in order to balance the two weighting methods. In order to select the best country in each cluster, a novel extension of the hybrid MARCOS (Measurement of Alternatives and Ranking according to Compromise Solution) method combined with Power averaging and Heronian operator was developed. According to final solutions, Western European countries in the first cluster have the lowest unemployment and corruption rates, with the Netherlands having the best performance in this cluster. The second cluster includes countries with the lowest employment rates following university graduates between the ages of 20 and 64. Accordingly, Croatia is the best social performance in this cluster. Countries with the highest income distribution and unemployment rate are in the 3rd cluster, the best country in this group is Lithuania. Finally, the results obtained from the innovative MCDM methods have validated in order to demonstrate the proposed methodology's applicability.
AtıfScopus30WoS23OpenAlex42İncele - MakaleAçık Erişim2023Scopus SJRQ1Investigation of Critical Raw Materials in Sludge of Municipal Wastewater Treatment Plant
Topal, Murat; Arslan Topal, E. Işıl
In the present research, lanthanum, vanadium, tungsten, scandium, bismuth, antimony, gallium, phosphorus, magnesium, and cobalt from critical raw materials (CRMs) were monitored for one year in the sewage sludges from an advanced biological wastewater treatment plant with the aim of presentation of possibility of using sewage sludge as a secondary source of critical raw materials. The amounts of the critical raw materials in sewage sludge were calculated annually, and economic values were revealed. Maximum concentrations of lanthanum, scandium, tungsten, bismuth, antimony, gallium, vanadium, cobalt, magnesium, and phosphorus were 4.3, 1.6, 0.5, 1.51, 1.27, 1.7, 23, 5.6, 6500, and 16,170 mg/kg, respectively. In the sewage sludge, the amount of CRMs, which have been formed annually, have been listed as tungsten < scandium < antimony < bismuth < gallium < lanthanum < cobalt < vanadium < magnesium < phosphorus. In autumn, summer, spring, and summer season, the mean highest concentration was for P, while the minimum concentration was for W. In sewage sludge, P and W elements were the highest and the least of the CRMs, respectively. With the recovery of CRMs in sewage sludge, the highest theoric achievable income is for Mg, while the lowest income is for Sb. It is determined that a total of 26,083.8 USD/year could be obtained by recovering the CRMs mentioned here from the sewage sludge.
AtıfScopus1WoS1OpenAlex3İncele - MakaleAçık Erişim2023Scopus SJRQ3Evaluation of waste polyethylene terephalate in polyol and polyurethane production
Fırat, Tülay; Kar, Filiz
As technology advances and human population grows, we must meet our diverse needs while minimising harm to the environment. One solution is to prioritise recycling and using second-hand consumer goods. In this study, PET flakes were depolymerised by glycolysis using different molar ratios of glycol such as propylene glycol(PG), triethylene glycol(TEG) and polyethylene glycol(PEG 400) in the presence of two different catalysts: zinc acetate- zinc sulphate. As a result, glycated products (polyols-PO) were obtained. The obtained polyols were then used to synthesise polyurethane films (PU) via acetone process. The thermal and chemical characterisations of the polyurethane films (PU) were analysed. In similar studies, zinc acetate was used as a transesterification catalyst for the glycolysis process. In this study, the same process was carried out using zinc sulphate and zinc acetate. Zinc sulphate was found to be a cheaper and eco-friendlier catalyst alternative to zinc acetate for the glycolysis process.
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