DSpace@ATÜ (Adana Alparslan Türkeş Bilim ve Teknoloji Universiti)
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Enhanced laccase separation from fermentation medium using cryogel columns
No full textThe laccase enzyme family belongs to the oxidoreductase enzyme class and is one of the most commercially valuable enzymes that catalyzes the oxidation of one electron of a wide range of phenolic compounds. Separation and purification of laccases are crucial for industry since they play an important role in dye decolorization, biodegradation and food processing. Therefore, developing effective, high yielding and cost-effective methods for laccase production is vital. In this study, it was aimed to prepare cryogel columns for laccase purification following the bioproduction of laccase via Aspergillus niger. 2-hydroxyethyl methacrylate based cryogels were synthesized in the presence of 1-vinylimidazole as the affinity ligand and characterized by swelling tests, Bru-nauer-Emmett-Teller surface area measurement and scanning electron microscopy analysis. Surface area and water uptake ratio of cryogel columns were 35 m2/g and 93 %, respectively. The effect of pH, equilibrium laccase concentration, flow rate, interaction time and temperature on laccase adsorption were examined. The purifi-cation factor was calculated as 10.53 under optimum conditions and the enzyme recovery was found to be 86.7 % from fermentation medium. Current study revealed that laccase purification using cryogels following filtration of fermentation medium could be a promising candidate for industrial applications with eliminating the need for complex chromatographic steps
Determination of the effects of frying process in oil used in making ring dessert
No full textLisansüstü Eğitim Enstitüsü, Gıda Mühendisliği Ana Bilim Dalı, Gıda Mühendisliği Bilim DalıHalka tatlı ülkemizde çok tercih edilen sokak tatlılarındandır. Hazırlanan hamur karışımının yağda kızartılmasıyla servise sunulan bir tatlıdır. Kızartma işlemi sırasında yağ kimyasal reaksiyonlardan geçer. Bunlar lipit hidrolizi, oksidasyon, polimerizasyon ve izomerizasyon gibi reaksiyonlardır. Bu reaksiyonlar, kızartma yağı kalitesini bozan zararlı bileşik üretir. Kızartma işlemi sonrasında yağ asitleri ve trans izomerleri oluşumu gerçekleşir. Trans yağ asitlerinin oluşum derecesinde; ortamın sıcaklığı ve hidrojen sağlığı, gazın basıncı ve dağılım derecesi, katalizör çeşidi aktifliği ve miktarı etkili olmaktadır. Bu araştırmada halka tatlı yapımında kullanılan kızartma yağlarının, kızartma işlemiyle beraber yağın değişen fiziksel özellikleri, kimyasal özellikleri ve trans yağ asitleri belirlenmiştir. Bu amaçla Adana ilinde 15 farklı halka tatlı üreticisinden kızartma öncesi ve sonrasına ait yağ örnekleri toplanmıştır. Elde edilen yağ örneklerinin fiziksel ve kimyasal özellikleri kalite açısından değerlendirilmiştir. Çalışma kapsamında yağların kırılma indisi, serbest yağ asidi, peroksit miktarı, renk analizi, sabunlaşma miktarı, iyot sayısı ve yağ asidi profilleri analiz edilmiştir. Analiz sonucunda kırılma indisi değeri 1.4735'den 1.4744'e, serbest yağ asidi miktarı 0.43 mg KOH/g yağ'dan 2.32 mg KOH/g yağ'a, peroksit miktarı 4.25 meq g O2/kg yağ'dan %6.52 meq g O2/kg yağ'a, sabunlaşma miktarı 193.52 mg KOH/g yağ'dan 256.90mg KOH/g yağ'a, b* değeri 10.53'den 33.21'e, c değeri 10.81'den 33.56'ya, trans yağ asidi olan elaidik asit miktarı %0.1969'dan %0.3109'a, linolelaidik asit miktarı %0.2724'den %0.2858'e düzenli olarak artmıştır. a* değeri -2,38'den -3,24'e, L* değeri 95,83'den 91.68'e, h değeri ise 102.82'den 98.64'e azalmıştır. Aynı zamanda iyot sayısı da 121.58'den 117.38'e azalmıştır. Yapılan çalışma sonrasında halka tatlıda yapılan kızartma işleminin yağ kalite değerlerinde belirgin bir azalmaya sebep olduğu belirlenmiştir. Bu dönüşümlerin insan sağlığına olumsuz etkileri vardır. Bu sebeple halka tatlı tüketiminin sınırlı tutulması önerilmektedir.Halka dessert is one of the most preferred street desserts in our country. It is a dessert served by frying the prepared dough mixture in oil. During the deep-frying process, the oil goes through chemical reactions. These are reactions such as lipid hydrolysis, oxidation, polymerization and isomerization. These reactions produce harmful compound that degrades frying oil quality. After frying, fatty acids and trans isomers are formed. In the degree of formation of trans fatty acids; the temperature and hydrogen health of the environment, the pressure and distribution degree of the gas, the activity and amount of the catalyst type are effective. In this study, the physical and chemical properties and trans fatty acids of the frying oils used in making halka desserts, which change with the frying process, were determined. For this purpose, oil samples were collected before and after frying from 15 different halka dessert producers. The physical and chemical properties of the obtained oil samples were evaluated in terms of quality. Within the scope of the study, the refractive index, free fatty acid, peroxide amount, colour analysis, iodine analysis, saponification amount and fatty acid profiles of the oils were analysed. As a result of the analysis, the refractive index value increased from 1.4735 to 1.4744, the amount of free oil increased from 0.43 mg KOH/g oil to 2.32 mg KOH/g oil, the amount of peroxide increased from 4.25meq g O2/kg oil to 6.52 meq g O2/kg oil, the saponification amount increased from 193.52 mg KOH/g oil to 256.90 mg KOH/g oil, the b* value increased from 10.53, c value increased regularly from 10.81 to 33.56, the amount of elaidic acid, which is a trans fat, increased from %0.1969 to %0.3109, the amount of linolelaidic acid increased from %0.2724 to %0.2858, the a* value decreased from -2.38 to -3.24, L* value decreased from 95.83 to 91.68, and h value decreased from 102.82 to 98.64. At the same time, the iodine count decreased from 121.58 to 117.38. After the study, it was determined that the frying process in the halka dessert caused a significant decrease in the oil quality values. These transformations have negative effects on human health. For this reason, it is recommended to limit the consumption of halka dessert to the public
Experimental investigation of usability of modified asphalt binder with waste expanded polystyrene (EPS)
No full textEPS (Expanded polystyrene) is widely used in construction and packaging industries. Unfortunately, EPS is not mostly recyclable because it might not be economically feasible to store, transport, and process EPS so that it becomes recyclable. Therefore, alternative waste management strategies are urgently needed. The main objective of this study is to experimentally investigate the potential use of waste EPS in asphalt binder modification. As part of this study, a base asphalt binder with a Penetration grade of 70/100 was modified with waste EPS in four different ratios (0%, 1.5%, 3% and 4.5%, by weight of asphalt binder). The modified asphalt binder specimens were tested based on several physical (penetration, ductility, softening points and viscosity) as well as rheological/Superpave binder grading system tests including Rolling Thin Film Oven (RTFO), Pressure Aging Vessel (PAV), Dynamic Shear Rheometer (DSR), and Bending Beam Rheometer (BBR). Based on the tests results, rheological and engineering properties of the modified asphalt binders were compared with the ones of the base binder so that effect of waste EPS addition on the properties of the base binder was evaluated; and how the Superpave binder grades of the modified binders were changed with the additions of waste EPS was discussed. It was found out that modifying asphalt binders with EPS provided them with a better rutting resistance at the expense of lowering their fatigue and low temperature cracking resistance. Overall, it could be concluded that waste EPS can be potentially used in the asphalt binder modification by paying special attention to these factors, and it should be noted that using waste EPS in the asphalt binder modification has many economic and environmental benefits
Optimization of black garlic production parameters using response surface methodology: Assessment and characterization of bioactive properties
No full textThis study was performed to determine the optimum process parameters for black garlic production. Central composite design (CCD) of the response surface methodology (RSM) was utilized to examine the effects of fermentation conditions (temperature, humidity and time) on the alliin, S-allyl cysteine (SAC), total phenolic content (TPC), antioxidant capacity, moisture, and 5-Hydroxymethylfurfural (HMF) contents of the black garlic samples. Liquid chromatography coupled to diode array detection and electrospray ionization tandem mass spectrometry (LC-DAD-ESI-MS/MS) was used for the identification and quantification of alliin, SAC and HMF. SEM and FT-IR techniques were also utilized to characterize the samples. The optimized fermentation parameters were determined as 65 degrees C temperature, 85% humidity, and a duration of 24 days. TPC was found to be 1152.46 mg GAE/100 g dry matter with the highest antioxidant capacity while SAC and alliin contents were 80.21 and 5.16 mg/100 g, respectively. The HMF was quantified as 0.60 g/kg using the optimized parameters. It was also found that decreased temperature and fermentation time yielded a decrement in HMF and an increment in the bioactivity of black garlic.Scientific and Techno- logical Research Council of Turkey, TUBITAK [TOVAG 219O174]Funding This study was financially supported by the Scientific and Techno- logical Research Council of Turkey, TUBITAK (Project no: TOVAG 219O174)
DETERMINING THE FACTORS THAT MOST AFFECT THE ECOLOGICAL FOOTPRINT UUSING THE ARTIFICIAL NEURAL NETWORK CLASSIFICATION FEATURE: THE CASE OF TURKEY
No full textSince the end of the 20th century, ecological problems have become a priority problem due to industrialization, urbanization, technological developments and rapid population growth. The change in human living standards causes many ecological problems such as unconscious consumption of natural resources, extinction of forests and living species. Ecological Footprint is developed to measure the demand pressure that people exert on the environment. In study, Neural Network Fitting Model was used in MATLAB, for the development Artificial Neural Network (ANN) by using the data of 1996-2018 to estimate Turkey's ecological footprint. Urban Population, Renewable Energy Consumption, R&D Expenditures and Human Development Index were chosen as independent variables. The data were obtained from the database of “World Bank Group” and “Human Development Reports”. For the ANN, Levenberg-Marquardt algorithm was used to determine the appropriate hidden layer and hidden neurons in each layer. The data used to train an artificial neural network using feedforward and backpropagation were randomly divided into three groups for training, testing and validation purposes. R values for each stage, respectively; 0.999, 0.948, was obtained as 1. According to the results obtained, the independent variable with the greatest effect on the ecological footprint was found to be the Urban Population
Singularly perturbed fuzzy initial value problems
No full textIn this work, we have firstly introduced singularly perturbed fuzzy initial value problems (SPFIVPs) and then we have given an algorithm for the solutions of them by using the extension principle given by Zadeh. We have presented some results on the behaviour of the.alpha -cuts of the solutions. To show the robustness of the given algorithm, we have fuzzified some examples given in the literature and then we have applied the algorithm
Thermal and thermodynamic optimization of the performance of a large aperture width parabolic trough solar collector using gaseous and supercritical CO2 as heat transfer fluids
No full textThe degradation of thermal-oil-based working fluids in parabolic trough solar collector (PTSC) systems at temperatures above 400 degrees C has accelerated the search for cost-effective and efficient heat transfer fluids (HTFs) for high-temperature applications. Carbon dioxide is abundant and has the potential to be used as a working fluid in PTSCs. In this work, the performance of a larger aperture width PTSC with CO2 as the working fluid (either in gaseous or supercritical phase) is investigated. A PTSC system with an aperture width of 9 m (geometric con-centration ratio of 113) was considered. The operating pressure is in the range of 40-100 bar, the HTF inlet temperatures are between 650-1000 K, and the flow rate varies from 32.6 to 653 m3/h. A thoroughly verified and validated computational model using a combination of Monte-Carlo ray tracing and computational fluid dynamics was used for the numerical investigations. In addition, the Realizable k-epsilon model was used for turbu-lence modeling. The results show that CO2 at 80 bar has comparable thermal performance relative to current thermal oil-based HTFs. Results further show that supercritical CO2 (sCO2) has the best thermal performance compared to gaseous CO2. Moreover, the entropy generation minimization method was used to determine the Reynolds number that minimizes the irreversibilities at a given operating pressure. At low pressures, much higher flow rates are required to achieve high heat transfer rates and reduce temperature gradients in the absorber tube. Furthermore, correlations have been developed for the optimal Reynolds numbers at which the entropy generation rate is minimum and the collector efficiency is maximum
Effect of surface roughness characteristics on the uplift capacity of piles: A physical modelling study
No full textPile surface roughness is one of the significant variables affecting the load-bearing capacity of piles. Especially for piles subjected to uplift loads, this parameter can be considered as the main factor that affects the uplift capacity since there is no contribution originating from the pile tip. According to limited previous research, a pile surface can be evaluated as smooth if pile surface roughness parameter (R-n) is less than 0.02, whereas the pile surface is considered completely rough when R-n value is greater than 0.10. This paper, therefore, is aimed to investigate the validity and effectiveness of the numerical limits previously suggested for R-n and intends to determine the relationship between R-n and soil-pile friction angle. For this purpose, laboratory model tests were performed on 12 small-scale pile models embedded in cohesionless soils having varying densities (D-r=25%, 50%, and 75%). Pile surfaces were specially textured to produce different surface roughness values from 0 to 2. Test results indicated that increasing the relative density of cohesionless soil and the pile surface roughness had a considerable contribution to the uplift capacity and soil-pile friction angle. Furthermore, some typical values of R-n like 0, 0.04, and 0.10 were found to be critical for pile uplift behaviour and capacity, and R-n value should be accepted as zero to consider the pile surface as completely smooth
TURKISH TEACHING TO PUBLIC IN VAKIT NEWSPAPER DURING THE ALPHABET REFORM PROCESS
No full textAfter the adoption of the Turkish alphabet based on Latin letters on November 1, 1928, in the Republic of Turkey, a comprehensive literacy campaign was organized. This process is called the “alphabet reform” in the historical literature. During the alphabet reform process, reading and writing were taught to the public in various institutions, and some newspapers also included pages that could be evaluated within the scope of teaching literacy to the public. One of these newspapers is Vakit newspaper. In the section titled “National Schools Page of Vakit Newspaper” in Vakit newspaper, various information and texts were available to provide education to the public. In this context, it can be said that Vakit newspaper had an important place in the history of Turkish teaching. In this study, it was aimed to examine the section titled “National Schools Page of Vakit Newspaper” in some issues of Vakit newspaper in 1929 in terms of Turkish teaching. In this context, 58 newspapers published in 1929, including the section titled \"National Schools Page of Vakit Newspaper\", were selected as samples. The examined newspapers were published between 4 January 1929 and 3 March 1929. In the study, in which the document analysis method was used, the data were analyzed with the content analysis technique. In the study, it was determined that Vakit newspaper played an active role in teaching Turkish to the public during the alphabet reform process
A STRUGGLE TO KEEP ENVIRONMENTAL PROTESTS ABOVE PARTY POLITICS: THE CERATTEPE CASE
No full textThe Cerattepe mining project for the extraction of gold and copper in the city of Artvin has been controversial since the mid-1980s. Local resistance against the project peaked in 2015-2016 in the form of blockages, sit-ins, social media protests, litigations, and signed petitions. This paper analyzes protests against the Cerattepe mining project in terms of their motivations, strategies, limitations, and political perceptions. Through an original survey analysis (N=253) and interview data, we find that the locals frame their activism as above party politics to keep a legitimate position in resisting the mining project. This strategy has remained intact for several years despite the politicization attempts of resistance from national-level political parties. We explain this strategy with the national consensus on prioritizing economic growth over environmental issues, neoliberal developmentalism with strong state support for private companies, and high levels of political polarization in society. Overall, the study offers an understanding of the challenges in front of environmental issue-based activism in Turkey and reveals the strategies of locals in resisting an environmentally destructive mining project