Yazarlar
- Duran, Celal(26)
- Ozdes, Duygu(21)
- Baltaci, Cemalettin(10)
- Gundogdu, Ali(10)
- Gül, Abdulkadir(9)
- Çullu, Mustafa(8)
- Aksüt, Yavuz Selim(7)
- Baltacı, Cemalettin(7)
- Barut, Abdulkadir(7)
- Bozbeyoglu, Pinar(7)
- Erol, Ismail(7)
- Ozeken, Sengul Tugba(7)
- Peker, Iskender(7)
- Eker, Hasan(6)
- Külekçi, Gökhan(6)
- Altuner, Elif Esra(5)
- Ar, Ilker Murat(5)
- Güzel, Melih(5)
- Karahan, Selim(5)
- Karpuz, Ömer(5)
- Kıranşan, Murat(5)
- Odabaş, Halil İbrahim(5)
- Seferoğlu, Mehmet Tevfik(5)
- Uysal, Turan(5)
- Demir Şahin, Demet(4)
- Imamoglu, Mustafa(4)
- Karpuz, Omer(4)
- Top, Yener(4)
- Akar, Bülent(3)
- Akpinar, Muhammet Vefa(3)
- Akpınar, Özlem(3)
- Avci, Ibrahim(3)
- Aydoğmuş, Ercan(3)
- Bozbeyoğlu, Pınar(3)
- Cakir, Mehmet Ali(3)
- Camoglu, Aslihan Yilmaz(3)
- Cavusoglu, Ibrahim(3)
- Daulay, Amru(3)
- Ercikdi, Bayram(3)
- Komut, Osman(3)
Yayınlar
- MakaleYalnız künye2022Alleviating the Impact of the Barriers to Circular Economy Adoption Through Blockchain: An Investigation Using an Integrated MCDM-based QFD With Hesitant Fuzzy Linguistic Term Sets
Erol, Ismail; Murat Ar, Ilker; Peker, Iskender; Searcy, Cory
Despite its clear potential to contribute to sustainability, there are many challenges to adopting circular economy (CE). These barriers impede the implementation of CE; however, research to address them is ongoing. For example, novel technologies have become a key enabler for easing the impact of CE adoption barriers. Blockchain is one disruptive technology that has the potential to address some of those barriers, notably technological, organizational, and ecological. Blockchain is particularly well suited to help address supply chain-oriented barriers to CE adoption. However, a review of the literature shows that while there are a limited number of conceptual studies that address the capabilities of blockchain to alleviate the impact of the barriers to CE, no previous study has focused on this vital subject using a decision tool based on expert data. To this end, this paper proposes an integrated decision framework involving Multi-Criteria Decision-Making (MCDM)-based Quality Function Deployment (QFD) method with Hesitant Fuzzy Linguistic Term Sets (HFLTS) to investigate the true potential of blockchain to address the CE adoption barriers. Our findings indicate that enhanced supply chain traceability management, improved collaboration and coordination in supply chain ecosystems, building higher levels of trust in supply chain ecosystems, and enhanced business models are the most significant functions of blockchain to help overcome the CE adoption barriers.
- MakaleYalnız künye2022Scrutinizing blockchain applicability in sustainable supply chains through an integrated fuzzy multi-criteria decision making framework
Erol, Ismail; Ar, Ilker Murat; Peker, Iskender
Sustainability has become increasingly important over the last three decades and has proven to be a key enabler for constructing resilient supply chains. Customers who want their products to be authenticated for sustainability put pressure on Original Equipment Manufacturers and suppliers to become more sustainable on a global scale. Moreover, social sustainability issues have become more challenging to address, and a growing number of stakeholders put emphasis on societal concerns. To this end, decision-makers are becoming increasingly interested in applying disruptive technologies to address societal, environmental, and economic concerns and accomplish sustainability goals. Researchers argue that disruptive technologies such as blockchain may be implemented to assist supply chains towards building sustainability. However, our literature analysis concluded that existing research has not quantitatively examined the critical functions of sustainable supply chain (SSC) for blockchain applicability using a decision framework. Therefore, this research, through Fuzzy SWARA-COPRAS-EDAS and COPELAND-based framework, is aimed at investigating the most feasible functions of a SSC for potential blockchain implementations. Using this framework, the critical functions of a SSC were ranked against the benefits of blockchain. The findings of this study implied that while sourcing, delivery, transformation and product recovery proved to be the most appropriate functions of SSCs for blockchain applications, customers and product use was the least feasible one. This study aids decision-makers in gaining a more thorough understanding of where in a SSC blockchain may create additional value.
- MakaleAçık Erişim2022Microwave decontamination process for hummus: A computational study with experimental validation
Son, Ezgi; Coskun, Eda; Ozturk, Samet; Bulduk, Kubra; Akpinar, Merve; Mert, Behic; Erdogdu, Ferruh
There has been an increasing demand for healthy snacks, and hummus is preferred as a plant-based product its rich protein content. Its increased consumption, on the other hand, has raised food safety issues with linkages to Listeria outbreak and a recent Salmonella related recall. These were observed in ready-to-eat hummus and indicated the requirement of further processing. Conventional thermal processes might require longer times with negative impact on the quality due to the high viscosity of hummus with its solid-like rheology. For an efficient process design, microwave (MW) processing might be considered with its volumetric heating feature. Therefore, the objective of this study was to present MW application for a decontamination process for hummus. For this purpose, a computational model was developed to determine the temperature change during the process. This model was validated using the experimentally obtained temperature data from samples processed in polystyrene petri dishes (60 g – 8.5 cm in diameter and 1.2 cm in height) in a lab-scale MW system. Color changes were determined, and changes in its viscosity were used to understand the variation in the rheological attributes. Hummus samples were also inoculated with Salmonella cocktail to ≈7–8 log10 CFU/g prior to the MW process, and 70 W MW processing for 5 min (to average temperature of 95.3 °C) resulted in >4 log cycle reduction. Changes in color and rheological attributes were not significant with rather limited mass losses, and these indicated the possible MW processing for hummus decontamination with the need of designing an industrial scale processing.
- MakaleAçık Erişim2022Insights into brewed tea waste as a green and low-priced adsorbent for solid-phase extraction of Cd(II) ions: isotherm, kinetic, and artificial neural network approach
Ozdes, Duygu; Tilki, Nida; Seker, Serdal; Duran, Celal
In the present research, brewed tea waste (BTW) was utilized as a green, low-priced, and abundant adsorbent for separation/preconcentration of Cd(II) ions through solid-phase extraction method from water and foods for the first time. BTW was applied as a natural adsorbent, without using any chelating agent to bind Cd(II) ions or any chemical reagent for its modification. A three-layer artificial neural network model using backpropagation algorithm was utilized to explicate a prediction model for the extraction performance of Cd(II) ions by selecting the input parameters as solution pH, quantity of BTW, sample volume, eluent concentration and volume, and equilibrium time for desorption. The preconcentration factor, relative standard deviation, and detection limit were attained as 100, 3.03%, and 0.56 µg L−1, respectively. It was decided that the Langmuir isotherm model is acceptable to characterize the retention of Cd(II) ions on BTW. This result pointed out that the active binding sites on the BTW surface are homogeneously distributed. Adsorption capacity of BTW was achieved as 41.5 mg g−1 which is higher than several expensive and difficult-to-prepare adsorbents. Adsorption kinetics was elucidated by pseudo-second order kinetic model. After confirmed the accuracy of the method with spike/recovery studies, it was employed for Cd(II) determination in water (stream and sea water) and food (eggplant, lettuce, parsley, apple, and apricot) samples with high accuracy. The inferences of the study proved that the BTW offers a magnificent application prospect in the extraction of Cd(II) ions.
- MakaleAçık Erişim2022Closing the Loop in Photovoltaic Solar and Wind Power Supply Chains: An investigation in Turkey through Neutrosphopic-DELPHI-based Force Field Analysis and Neutrosphopic-DEMATEL
Erol, Ismail; Peker, Iskender; Turan, İsmet; Benli, Tolga
Since solar panels and wind turbines have limited lifespans, solar photovoltaic energy supply chain (SPvESC) and wind energy supply chain (WESC) in Turkey needs a paradigm shift to improve the efficiency and recyclability of solar panel and wind turbine components. The circular economy (CE) is a viable strategy for reducing the negative effects of linear supply chains in the SPvESC and WESC. However, despite the several drivers of implementing CE in the SPvESC and WESC, there are also barriers to CE initiatives. It is argued that further studies are needed to explore the drivers and challenges for CE adoption in different industries of developing and developed countries. Hence, the goal of this research is to explore the driving and restraining forces for CE adoption in Turkey's SPvESC and WESC through a decision framework that includes Neutrosphopic DELPHI-based Force Field Analysis, Neutrosphopic-DEMATEL, and Nominal Group Technique. The findings of this research suggested that because the total score of restraining forces is higher than that of driving forces in force field analysis, it is critical to investigate the relationships among the restraining forces. Our findings also suggested that nonexistence of effective incentives and regulations proved to be the most prominent restraining force.
- MakaleAçık Erişim2021Yeşil restoranlarda hizmet alan müşterilerin memnuniyet ve şikâyetlerinin incelenmesi: Akdeniz ülkelerinden örnekler
Akyürek, Suat; Kızılcık, Onur
Son yıllarda dünya genelinde sürdürülebilir ve çevreci restorancılık anlayışıyla faaliyet gösteren restoran sayısının oldukça artış gösterdiği görülmektedir. Ancak Türkiye’de bu anlayışla faaliyet gösteren restoranlar sınırlı sayıda kalmıştır. Dünya genelinde çevresel sorunların hızla büyümesi ile birlikte, sürdürülebilirlik kapsamında alınan önlemler de artmaktadır. Bu bağlamda çevre dostu restorancılık anlayışının gelecek yıllarda daha da yaygınlaşacağı öngörülmektedir. Bu nedenle, çevre dostu restoranlardan hizmet alan turistlerin memnuniyet ve şikâyet kategorilerinin incelenmesi ile teorik ve pratik açıdan faydalı bulgulara ulaşılacağı düşünülmektedir. Turistlerin çoğunluğu seyahat planlamalarında çevrimiçi seyahat bilgi kanallarını kullanmaktadır. Buradan hareketle bu çalışmada, yeşil restoranlarda hizmet alan müşterilerin çevrimiçi değerlendirmeleri kapsamında memnuniyet ve şikâyet kategorilerinin keşfedici bir yaklaşımla ortaya konulması amaçlanmıştır. Bu amaç doğrultusunda, örnek olay nitel araştırma yöntemi benimsenerek, Türkiye, İspanya, İtalya ve Fransa’da faaliyet gösteren yeşil restoranlara yönelik paylaşılan toplam 600 yorum içerik analizine tabi tutulmuş ve elde edilen kategoriler dört ülke kapsamında incelenmiştir. Araştırma sonucunda, ortaya çıkan kategorilerin benzerlik gösterdiği ve neredeyse tüm müşterilerin (%99) herhangi bir yeşil veya sürdürülebilirlik vurgusuna yorumlarında yer vermedikleri tespit edilmiştir.
- MakaleAçık Erişim2021The Investigation of the Alternative Fuel Biogas Potential for Model Town
Saribiyik, Oguz Yunus; Kılıç, Rahman
The investigations have been intensively continuing for responding of energy and food demand depending on the world populationincrease and the development of the industrial progression. The energy necessities eliminate by using fossil fuels based sources suchas natural gas, coal and petrol. However, the amount of the fossil fuels is limited and they create the green houses gas problems,therefore, many of the researches have been focusing on new sustainable alternative energy sources, such as wind power, biodiesel,biogas, solar and biomass. The methane which is released by the methanogen bacteria is occupy a places in green gases which arecarbon dioxide and methane. Biogas as an alternative biofuel has higher impact in alternative fuels because of its applicability,sustainability, low production cost, keep the greenhouse gases in balance and produces bio-fertilizer after digestion processes. In thosepurposes, the biogas investment and investigation increases for all over the world however the potential of biomass conversion andthe examination for bio gas production have paid less concern in our country.In this study, the potential biomass and the amount of the biogas depending on the biomass potential have been investigated on one ofthe model town, Şiran in Gümüşhane. According to obtained results, it is seen that the biomass potential and the amount of the biogasproduction are highly enough for model town for natural gas demand and using bio fertilizer which is produced after digestion ofbiomass can be decreased by the utilization of the synthetic inorganic fertilizer, causing for soil pollution.
- MakaleAçık Erişim2021The investigation of mechanical properties of polypropylene fiber-reinforced composites produced with the use of alternative wastes
Külekçi, Gokhan; Çullu, Mustafa
Various studies on the disposal or storage of the wastes generated due to mining activities have been carried out until today. With the developing technology, the use of alternative products instead of aggregates in Composite and the effect of fiber addition were investigated. The most common of these studies is the bending strength tests on the beam sample. In this study, solid wastes generated by mining operations were used instead of aggregate used in Composite. Beam samples were poured with the dimensions of 40x40x160 mm by adding 4-6 kg/m(3) polypropylene fiber to the mixture obtained by using these solid wastes; then, its effects on ultrasonic pulse velocity test, tensile test, and compressive strength tests were conducted. According to the results of these tests, it was found that the fibers had a positive effect on compressive strength and bending strength. Also, it was found that water absorption rates and densities did not have an effect, while the ultrasonic pulse velocity decreased with increasing fiber content.
- MakaleAçık Erişim2021Investigation of the removal of sulfamethoxazole drug waste from aqueous solutions under the effect of zinc oxide/montmorillonite nanocomposite by photocatalytic ozonation process
Özyürek, Işıl Nihan; Kıranşan, Murat; Karaca, Semra
In this study, the synergistic effect of photocatalysis and ozonation processes to degrade the sulfamethoxazole (SMX), one antibiotic pharmaceutical compound, has been studied through the influence of main operational variables such as zinc oxide/montmorillonite (ZnO/MMT) dos-age, SMX initial concentration, ozone flow rate, pH and the addition of organic and inorganic scavengers. Synthesized ZnO nanoparticles were immobilized on the montmorillonite surface to prepare ZnO/MMT catalyst as a photocatalyst. The catalyst was characterized by X-ray fluo-rescence, X-ray diffraction, scanning electron microscope, high-resolution transmission electron microscope and N2 adsorption/desorption. The highest SMX degradation efficiency (80.84% for 30 min of reaction time) was obtained for the photocatalytic ozonation process compared to adsorption, single ozonation, catalytic ozonation, and photolysis. ZnO/MMT was more effective photocatalyst according to ZnO, indicating its usability as a promising photocatalyst for the removal of organic contaminants in aqueous solutions. The reduced degradation efficiency with the addition of organic and inorganic scavengers showed the important role of the photo-produced radicals and holes as well as direct ozonation in SMX degradation. A mechanism is also proposed for photocatalytic ozonation degradation by using the gas chromatography-mass spectroscopy (GC-MS) analysis method. Finally, several by-products were identified by GC-MS analysis, which allowed to depict a possible mechanism for the sulfamethoxazole degradation.
- MakaleYalnız künye2021Simultaneous separation and preliminary purification of anthocyanins from Rosa pimpinellifolia L. fruits by microwave assisted aqueous two-phase extraction
Odabaş, Halil İbrahim; Koca, Ilkay
Rosa pimpinellifolia L. fruits (RPF) have great industrial potential due to the high presence of anthocyanins. In this work, microwave-assisted aqueous two-phase extraction (MA-ATPE) was applied to simultaneous extraction and purification of anthocyanins from RPF with ethanol/ammonium sulfate aqueous two-phase system (ATPS). MA-ATPE process was optimized by single-factor experiments and response surface methodology. The optimal anthocyanin yields were achieved in conditions of 0% HCl (w:w), 26.85% ethanol (w:w), 19.15% ammonium sulfate (w:w), liquid to solid ratio 40, 17.29 min, 60 °C and 400 W. Predicted anthocyanin yield of MA-ATPE at optimum conditions were determined as 1373.04 mg cyanidin 3-glucoside equivalent/g dry RPF. The purity of anthocyanin rich extract obtained by MA-ATPE was 1.65-fold greater than microwave assisted extraction using 80% ethanol (MAE). The compositional characterization of anthocyanins were carried out with HPLC-QTOF-MS. MA-ATPE had no obvious changes on anthocyanin composition when compared to MAE. Results indicated that the MA-ATPE could be a promising method for the extraction and preliminary purification of anthocyanins from different plant materials.
- MakaleYalnız künye2021Effects of puzzolanic materials in surface paste disposal by pilot-scale tests: observation of physical changes
Bascetin, A.; Adiguzel, D.; Eker, H.; Odabas, E.; Tuylu, S.
There are only a few pilot schemes, especially among scientific studies carried out to solve numerous environmental and ecological problems created by water during tailing storage on the surface. It is extremely important to establish precautions that can be taken, especially in the tailing storage process by examining the physical, chemical, mineralogical, and geotechnical changes that develop due to the effect of moisture in the tailing and surface water. In this study, 2 different pilot-scale designs of storage with no additions (reference) and with binder additions (cement and fly ash) to some layers were observed in field conditions for about 1 year to determine the effects of seasonal changes on paste material. The results of the measurements revealed that the water content of the reference design was ~ 10% higher than that of the design with cement addition at the substrates that provide stability and sudden temperature changes at the top layer of the reference design was found to be ~ 35 °C. Maximum sudden temperature changes in layers with cement addition and layers with cement and fly ash addition were observed to be ~ 15 °C. As a result, the use of cement has made the material more resistant to external factors. However, the study also revealed that fly ash could be used instead of cement with a substitute rate of 50% to reduce the cost for long-term storage in terms of industrial applications.
- MakaleYalnız künye2021Additivity effect on properties of cemented coal fly ash backfill containing water-reducing admixtures
Cavusoglu, Ibrahim; Yilmaz, Erol; Yilmaz, Ali Osman
Cemented coal fly ash backfill (CCB), a flowable structure of coal fly ash, binding agent and mixing water, has been often employed in mining operations to offer ground support as well as waste disposal solutions. An appropriate CCB mass should have sufficient rheological (e.g., workability) and mechanical (e.g., strength and stability) characteristics. Chemical admixtures are well known to greatly enhance the pumpability and strength properties of cementitious materials. Thus, this work provides the effect of water-reducing admixtures (namely, Sikament MR 50 W and Sikament FFN) on characteristics of CCB materials manufactured at a constant slump value. The role of admixtures in CCB mix is to reduce the cement-related costs, to modify the properties of the hardened backfills, and to ensure the quality of the backfill during mixing, transporting, placing, and curing. These admixtures were used at a dosage of 1% and 2% by weight of anhydrous material on cement. Several laboratory tests including slump, setting time, uniaxial compressive strength, scanning electron microscopy and mercury intrusion porosimetry were undertaken on CCB samples to understand their fresh and hardened performance. Experimental results show that the admixtures used ensure the slump required to deliver CCB at low water/cement ratios, improve short- and long-term backfill strengths up to 33%, and decrease the total porosity of the tested CCB. The findings of this study also show that the admixture use in CCB leads to a significant decrease in the considered cement content and a remarkable increase in the mechanical strength. As a result, understanding the actual fresh and hardened properties of CCB remains crucial for the choice of the greatest acting backfill admixture and for a fruitful change from capable experimental results to the in-situ conditions.
- MakaleYalnız künye2021Preparation of melon peel biochar/CoFe2O4 as a new adsorbent for the separation and preconcentration of Cu(II), Cd(II), and Pb(II) ions by solid-phase extraction in water and vegetable samples
Ozdes, Duygu; Duran, Celal
The present research describes the successful preparation of melon peel biochar modified with CoFe2O4 (MPBC/CoFe2O4) followed by its usage as a new sorbent to separate, preconcentrate, and determine the toxic heavy metal ions by magnetic solid-phase extraction. The metal ion desorption was performed by 0.1 M HCl solution with a volume of 5.0 mL. Flame atomic absorption spectrometry (FAAS) was utilized for detection of the analyte levels. SEM–EDX, TEM, XRD, and FTIR techniques were carried out to illuminate the structure of MPBC/CoFe2O4. The fundamental variables affecting the adsorption and elution efficiencies of the analyte ions including solution pH, MPBC/CoFe2O4 amount, type and concentration of eluent, adsorption and desorption equilibrium time, and sample volume were optimized. The detection limits were calculated as 0.41, 1.82, and 3.16 µg L−1 for Cu2+, Cd2+, and Pb2+ ions, respectively, with the relative standard deviation of lower than 4.2%. There were no substantial interference effects on the analyte ion recovery due to the presence of foreign ions at high levels. Five minutes of contact time was adequate to attain the adsorption equilibrium. The adsorption capacity of MPBC/CoFe2O4 was obtained as 106.4, 65.4, and 188.7 mg g−1 for Cu2+, Cd2+, and Pb2+ ions, respectively, by utilizing Langmuir isotherm model. The pseudo-second order model is favorable to identify the adsorption kinetics. The method was validated by spike/recovery test, and then, it was successfully implemented to determine the aforementioned analyte levels in sea and stream water, pepper, black cabbage, eggplant, and tomato samples.
- MakaleAçık Erişim2021The effect of pozzolans and mineral wastes on alkali-silica reaction in recycled aggregated mortar
Külekçi, Gökhan
In this study, it was aimed to examine recycled aggregates (RA), which are considered as aggregates, in terms of alkali-silica reaction (ASR) before being used in concrete, to determine the risk status and to reduce the ASR value. In order to reduce and stop the ASR, the cement was replaced with clay brick and fly-ash by 10–40 %. Marble waste and Pb-Zn mine waste were used instead of RA in order to reduce aggregate reactivity. At the end of 28 days, compared to the control sample, it was observed that mortar bar samples containing tailings instead of fine RA has 18 % less expansion and marble waste (MW) added samples again instead of fine RA has 34 % less expansion. Furthermore, 40 % fly ash (FA) added samples decreased the level of ASR for 96 %, and in 10 % clay brick mixed samples ASR formation is decreased to 85 %. As a result, recycled aggregates were determined to be reactive for ASR. It has been determined that marble and lead-zinc mine facility wastes added as replace with to RA reduce the expansion effect by ASR in the cement paste. With this study, it has contributed to the safe use of the increasing use of RA in the world.
- MakaleYalnız künye2021Extraction of Metals from Scrap Marble Cutting Segments in Nitric Acid Solutions
Celep, Oktay; Orak, Mürsel; Yazici, Ersin Y.; Deveci, Hacı
Extraction of cobalt, copper, and silver from scrap saw-blade segments using nitric acid solutions (0.1–0.4 M, 20–60°C) were investigated using response surface methodology. Extraction of cobalt and iron was more extensive than copper and silver, i.e., 35.7–96.2% Co and 72.6–100% Fe versus 8.50–35.4% Cu and 8.11–22.5% Ag. Statistical analysis of the experimental data has shown that increasing the acid concentration or temperature enhances the rate and extent of leaching of metals. Under suitable conditions, almost complete leaching of cobalt (99.9%), as well as high extractions of copper (95.9%) and silver (94.9%), were achieved. The activation energy, calculated to be 40.3 kJ/mol, indicates that nitric acid leaching of these metals occurs as a chemically controlled reaction. These findings have demonstrated that nitric acid as an effective oxidant/leaching agent could be suitably used for the extraction of cobalt, copper, and silver from scrap segments.
- MakaleYalnız künye2021Experimental Investigation of Usability of Construction Waste as Aggregate
Kulekci, Gokhan; Yilmaz, Ali Osman; Cullu, Mustafa
The aim of this work is to obtain recycled aggregate (RA) from construction debris in order to reduce the rapid consumption of aggregate resources and the environmental impact of these resources. In order to fulfill this aim, the density, porosity, Schmidt hardness test, uniaxial compression resistance, carbonation depth, and ultrasonic p-wave velocity experiments were conducted on different construction debris transported by trucks from 9 different points in Turkey. In addition, the debris samples taken were broken down to the size of the aggregate and subjected to the tests of density, porosity, moisture content, freeze-thaw, and impact resistance. As a result of the conducted experiments, the lowest mass loss as a result of freezing-thawing was in GRA with 9.36%, the highest mass loss was in ORA with 22.58%, the highest ORA average aggregate impact strength index was 21.27%, and the lowest TRA aggregate impact strength index was found to be 18.26%. İt was determined that most of the physical properties of RA obtained from the construction wreckage was within the limit values specified in the literature and that the recycled aggregates could be used instead of natural aggregate. With this work and these results, RA obtained could be used in many areas such as concrete aggregate in the construction sector, underground filling in mining, filling material in gunned concrete, and filling materials on highways.
- MakaleAçık Erişim2021Production and characterization of zinc oxide nanoparticles in microsystems via green synthesis; [Yeşil sentez yoluyla mikrosistemlerde çinko oksit nanopartiküllerin üretimi ve karakterizasyonu]
Akay, Şeref; Sefaoğlu, Melike
Nanoparticles (NP), which can be produced for many different fields and purposes; are at size vary from nanometer to a micrometer. These particles can be prepared by different approaches such as chemical, physical and biological methods. However, the biological approach is the most promising approach among other methods due to its simplicity and environmentally friendly conditions. The production of the nanoparticle by means of a biological approach does not require any high temperature, acidic/basic conditions and hazardous chemicals. Therefore, this method is named “green synthesis”. Development in microtechnology has had profound effects in many areas such as drug discovery, biology, diagnosis, and tissue engineering. Microfluidics which focuses on the processing of liquids in microscale systems has attracted wide attention in the production process of nanoparticles due to precise control and fast mixing. The main purpose of this study is to produce and characterize metal nanoparticles by combining microsystems and green synthesis approaches. For this purpose, in the first step, the design of microsystems that suitable for the flow of different phases was performed. In the second step, ZnO nanoparticle synthesis was carried out using the red cabbage (Brassica oleracea var.capitata f. Rubra) extracts. The synthesis of nanoparticles achieved by optimizing different parameters such as; extract: zinc ratio, zinc solution concentration, flow rates, and flow rates ratio in the microsystem and temperature. The results showed that the herbal red cabbage components can be used for the green synthesis of ZnO nanoparticles.
- MakaleYalnız künye2021Single-step recovery of pectin and essential oil from lemon waste by ohmic heating assisted extraction/hydrodistillation: A multi-response optimization study
Tunç, Merve Tuğçe; Odabaş, Halil İbrahim
The main products obtained from citrus wastes are pectin and essential oil. In this work, ohmic heating assisted extraction/hydrodistillation (OHAE/H) was applied for the simultaneous recovery of pectin and essential oil from lemon waste. Optimum OHAE/H conditions to maximize the yield of pectin and essential oil were determined with response surface methodology. Three independent variables, namely liquid to solid ratio (w:v), extraction/hydrodistillation time (min) and voltage gradient (V/cm) were varied to obtain maximum pectin and essential oil yield. Optimum OHAE/H conditions were determined as 8.7:1 liquid to solid ratio, 58.4 min extraction/hydrodistillation time and 14.2 V/cm voltage gradient. The predicted pectin and essential oil yields at optimum conditions were 16.58 and 3.62 g/100 g lemon waste, respectively. Data analysis showed that all of the independent variables significantly affected the pectin and essential oil yield. In the verification study, close agreement was found between predicted and experimental values. Conventional heating extraction/hydrodistillation (CHE/H) were conducted to evaluate the effectivity of OHAE/H. With OHAE/H process, the yields of the pectin and essential oil were significantly increased when compared to CHE/H. Limonene concentration of the essential oil produced with OHAE/H was higher than the essential oil produced by CHE/H. Results demonstrate that the single-step OHAE/H could be an effective method for simultaneous extraction and hydrodistillation of pectin and essential oils.
- MakaleYalnız künye2021Towards a circular economy: Investigating the critical success factors for a blockchain-based solar photovoltaic energy ecosystem in Turkey
Erol, Ismail; Peker, Iskender; Ar, Ilker Murat; Turan, İsmet; Searcy, Cory
Novel business models can be implemented through digital platforms to enable better circular economy (CE) performance in the renewable energy industry. For example, blockchain can assist in developing innovative business models throughout the solar photovoltaic energy ecosystem (SPVEE) to improve CE. Ranked fifth in total installed photovoltaic (PV) capacity, Turkey, as a developing country, should take the necessary steps and make progress towards achieving CE in the SPVEE. The solar PV industry requires further innovation to address the negative environmental impact of existing linear business models. To ensure favorable results, identifying and evaluating critical success factors (CSFs) are necessary. However, no study has investigated CSFs for SPVEE or any other renewable energy source to achieve a blockchain-based infrastructure towards increased CE performance. Therefore, the goal of this study is to identify and examine the CSFs to improve the performance of a blockchain-based SPVEE towards CE in Turkey. To this end, first, the CSFs for blockchain-based SPVEE were identified through both a literature review and the Nominal Group Technique (NGT). Then, Intuitionistic Fuzzy (IF)-DEMATEL was used to explore their interrelationships based on the expert data. Finally, IF-DELPHI was employed to validate the results. Our findings suggested that effective government incentive programs and regulations are significant for blockchain-based SPVEE towards CE in Turkey. The findings of this study assist macro and micro decision-making in the potential implementation of blockchain in Turkish SPVEE to improve CE. They are also invaluable for other countries and can be used as a reference point.
- MakaleYalnız künye2021Analysis of relationships between nanotechnology applications, mineral saving and ecological footprint: Evidence from panel fourier cointegration and causality tests
Koç, Pınar; Gülmez, Ahmet
Analyzing the relationship between nanotechnology applications, mineral saving, and environmental degradation is important to achieve sustainable development goals. However, in the literature, no study empirically examines the interaction among nanotechnology applications, mineral saving, and environmental degradation. This study addresses this significant gap in the literature by investigating the impacts of nanotechnology applications on mineral saving and the ecological footprint in 9 countries (Australia, Canada, China, France, Japan, Korea, Russia, Sweden, and the USA) in the period 1990–2017 using the combined panel fourier fractional cointegration and panel fractional fourier causality test. According to the causality test results based on group statistics, there is a Granger causality from nanotechnology applications to mineral saving. Also, there is causality from mineral saving to ecological footprint. The estimations of the causality based on individual statistics show no causality linkage between nanotechnology applications and mineral saving in the countries, excluding Australia and France. Canada, China, France, and Sweden are countries with unilateral causality from nanotechnology applications to ecological footprint. In the other countries, except China, Japan, and the USA, mineral saving doesn't Granger cause ecological footprint. The long-run findings show a positive impact of nanotechnology applications on mineral saving and ecological footprint. These findings are valid for all countries. In this context, it can be concluded that nanotechnology applications are essential for resource-saving. But, to save resources, the authorities should focus on controlling and measuring nanoparticle emissions.
