Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Dertli, Enes(116)
- Şahin, Engin(48)
- Kaya, Yunus(46)
- Özen, Soner(46)
- İspirli, Hümeyra(45)
- Pat, Suat(44)
- Şenay, Volkan(42)
- Korkmaz, Şadan(36)
- Yilmaz, Mustafa Tahsin(33)
- Kutlu, Naciye(32)
- Cuce, Erdem(31)
- Öner, Erdal(31)
- Artar, Musa(30)
- Ertugrul, Mehmet(29)
- Hasar, Ugur Cem(29)
- Mercan, Emin(28)
- Bayraktar, Bülent(27)
- Bayram, Sinan(27)
- Can, Zehra(25)
- Ecem Bayram, Nesrin(25)
- Çolak, Murat(23)
- Özdemir, Akın(23)
- Cuce, Pinar Mert(22)
- Sert, Durmuş(22)
- Ayata, Ümit(21)
- Bayram, Ozkan(21)
- Dirican, Ebubekir(20)
- Abdioglu, Murat(19)
- Ayazoglu, Rabil(19)
- Birinci, Ahmet(19)
- Kamiloğlu, Aybike(19)
- Gerçek, Yusuf Can(18)
- Taylan, Osman(18)
- Tozlu, Alperen(18)
- Gul, Volkan(15)
- Hasar, Ugur C.(15)
- Kadakal, Mahir(15)
- Sagdic, Osman(15)
- Ergün, Mustafa(14)
- Kadakal, Huriye(14)
Yayınlar
- MakaleYalnız künye2020Scopus SJRQ2Investigating the Optimum Model Parameters for Casting Process of A356 Alloy: A Cross-validation Using Response Surface Method and Particle Swarm Optimization
Şensoy, Abdullah Tahir; Çolak, Murat; Kaymaz, Irfan; Dispinar, Derya
This study aimed to determine the optimal casting parameters for the maximum fluidity of A356 alloy. Gravity die cast method was used. For this purpose, central composite design (CCD) was performed. The input parameters and their limits for the trial design were selected as pre-heating temperature (100–400 °C), casting temperature (680–760 °C), and cross-sectional thickness (1–10 mm). Using the CCD-based simulation results of the feed distance, a highly correlated full-quadratic regression equation was obtained with the highest R2 (0.99), which then was used as the objective function for the particle swarm optimization (PSO) process. The highest value of the response parameter, flow distance, reached up to 491.19 mm when the input parameters were selected as 400 °C, 760 °C and 10 mm, respectively. The sensitivity analysis has shown that the most effective parameter on the fluidity is the cross-sectional thickness. The response surface method (RSM)-based optimization results have been also validated using the PSO method. Although the higher temperatures have been found to result in better fluidity, there may be some drawbacks to working at higher temperatures such as energy cost and mould life. To determine the optimum input parameters, the RSM model suggested in this study can be modified for any type of casting process. Moreover, especially for a complex-shaped part, the manufacturer can be advised regarding operating conditions such as pre-heating and casting temperatures.
AtıfScopus11WoS9OpenAlex13
İncele - MakaleAçık Erişim2020Scopus SJRQ3Influence of lactobacillus reuteri on internal organ weight, performance and meat quality of Japanese quail (Coturnixcoturnix japonica) under heat stress; [Einfluss von lactobacillus reuteri auf das gewicht der inneren organe, die leistung und die fleischqualität Japanischer Wachteln (Coturnix coturnix japonica) unter Hitzestress]
Tekce, E.; Bayraktar, B.; Aksakal, V.; Dertli, E.; Kamiloğlu, A.; Çinar Topçu, K.; Kaya, H.; Takma, C.; Yasulergezer, N.
In the present study, the effects of Lactobacillus reuteri E81 (LRE) supplemented at different doses (200, 400 and 600 mg/kg) into the diets on performance, meat quality and internal organ weights of Japanese quail (Coturnixcoturnix japonica) were investigated under heat stress (HS) conditions (37°C). For the experiments, 448 one-day old quails were used. Seven days of training (physical exercise) and a 35-day fattening period were applied. On day 7 of the trial, 8 groups [4 under control temperature of 25°C (CT): control (C), LRE-200, LRE-400 and LRE-600 and 4 under HS: control (HSC), SLRE-200, SLRE-400 and SLRE-600] were formed, each group consisting of four replicates with 14 quail each. At the end of this study, the CT group fed 400 mg/kg LRE showed the best performance results, whereas no effect was found for groups under HS in comparison to the control group (HSC). Samples taken on the 21st and 42nd day revealed that addition of probiotics in the CT and HS groups induced no effect on weight of the internal organs (p > 0.05). Analysis of meat quality on the 21st day showed that LRE caused an increase in pH in both the HS and CT groups. Further, 400-mg/kg LRE supplementation induced an increase in thiobarbituric acid reactive substances (TBARS) in the group under HS. In the CT groups on day 42 no effect of LRE was found on colour parameters or on the TBARS value, except for a decrease in the pH value in the LRE supplemented groups compared with the control. In HS groups a decrease in the L* value and an increase in the TBARS value was found compared to CT groups (p < 0.05), but there was no effect on other colour parameters or pH value. In conclusion, in the present study supplementation of different doses of LRE E81 to quail diets had no effect on performance, internal organ weight or meat quality under HS.
AtıfScopus2WoS2OpenAlex6İncele - MakaleAçık Erişim2020Scopus SJRQ2Magnetic force and stiffness performances of Maglev system based on multi–surface arrangements with three-seeded bulk YBaCuO superconductors
Ozturk, K.; Abdioglu, M.; Karaahmet, Z.
We have designed a multi–surface HTS (high temperature superconductor with three seeded bulk YBaCuO) Maglev system by increasing the YBaCuO number while decreasing the PM number in HTS–PMG system to enhance the loading capacity and stability of the superconducting Maglev system while reducing the fabrication cost. By this study, a detailed investigation on the magnetic levitation force, guidance force, magnetic stiffness and cost analysis of the multi–surface HTS Maglev system has been carried out for the first time. In this study, it is determined that the multi–surface YBaCuO–PMG arrangements are superior to the single–surface arrangements with respect to the loading capacity and especially the movement stability of Maglev systems together. Additionally, it is seen that the using of the multi–surface YBaCuO–PMG arrangement reduces the fabrication cost of the Maglev systems as 42.0% for 1000 km magnetic rail while increasing of the levitation force efficiency as 43.4% and this emphasizes the advantage of multi–surface arrangements to the classical single–surface ones. The obtained results can contribute to the researchers working on Maglev and have a capability to increase the usage potential of Maglev systems in commercial applications because of both the loading capacity and stability of Maglev systems can be enhanced together with reducing the fabrication cost without any loss in levitation performance.
AtıfScopus19WoS18OpenAlex21İncele - MakaleYalnız künye2020Scopus SJRQ4Candida zeylanoides as whole-cell biocatalyst to perform asymmetric bioreduction of benzophenone derivatives
Şahin, Engin
Candida zeylanoides P1 was investigated as whole cell biocatalyst for the bioreduction of biaryl prochiral ketones into chiral carbinols, which can be used as pharmaceutical intermediate. Bioreduction of different biaryl ketones was carried out to their corresponding chiral biaryl carbinols such as (S)-(4-chlorophenyl) (phenyl) methanol (2a), which can be used in the synthesis of L-cloperastine drug, with antitussive, antiepidemic activity and bronchial musculature relaxant characteristics, in gram scale, enantiopure form (>99%) and excellent yields. The selectivity of C. zeylanoides P1 in enantioselective reduction of biaryl ketones was not affected by the steric and electronic effects of substrates. The current method demonstrates an encouraging green chemistry approach for the production of biaryl secondary chiral alcohols of pharmaceutical importance in mild, inexpensive and environmentally friendly process. The present study has many benefits since this yeast biocatalyst were successfully applied bioreduction of structurally bulky prochiral substrates, which cannot be reducted by chemical catalysis.
AtıfScopus10WoS9OpenAlex10İncele - MakaleAçık Erişim2020Scopus SJRQ2Graphene/polyaniline nanocomposite as platinum-free counter electrode material for dye-sensitized solar cell: its fabrication and photovoltaic performance
Bayram, Ozkan; Igman, Erdal; Guney, Harun; Demir, Zeynep; Yurtcan, Mustafa Tolga; Cirak, Cagri; Hasar, Ugur Cem; Simsek, Onder
In this study, it was aimed to produce graphene/polyaniline nanocomposite thin films as counter electrode materials by PECVD system and to determine the photovoltaic performances of these counter electrodes in dye-sensitized solar cells (DSSCs). Graphene/polyaniline counter electrode (GPCE) material was produced in two different steps. Firstly, a single-layer and multilayer graphene thin films were produced on the fluorine-doped tinoxide (FTO) substrates. Then, polyaniline (PANI) thin films were grown on each graphene thin films using plasma polymerization technique, and eventually the production of the graphene/PANI nanocomposite was completed. The fabricated graphene/PANI nanocomposites were used in place of platinum (Pt)-counter electrode which is widely used in DSSCs and the photovoltaic performance of these counter electrodes was investigated. The DSSCs consisted of titanium dioxide (TiO2) nanotube photoanode, N719 dye, iodolyte liquid electrolyte, and graphene/PANI nanocomposite counter electrode. I–V measurements were carried out in order to calculated photoconversion efficiency (PCE) and it was found that the these efficiency of GPCEs changed between 0.56 and 1.36% according to the number of graphene layers. The photovoltaic performance of DSSC, consisting of TiO2 nanotube photoanode and Pt-counter electrode was 1.1%.
AtıfScopus33WoS25OpenAlex29İncele - MakaleYayıncıda açık erişim2020Scopus SJRQ2Response of Japanese quails (Coturnix coturnix japonica) to dietary inclusion of Moringa oleifera essential oil under heat stress condition
Tekce, Emre; Bayraktar, Bülent; Aksakal, Vecihi; Dertli, Enes; Kamiloğlu, Aybike; Çinar Topcu, Kübra; Takma, Çiğdem; Gül, Mehmet; Kaya, Hacer
The present study was aimed at investigating the effects of the dietary use of different doses of Moringa oleifera essential oil (MOEO) on performance parameters, internal organ weights and meat quality in Japanese quails (Coturnix coturnix japonica) exposed to Heat Stress (HS). For this purpose, 320 male day-old quail chicks were used. Seven days of preliminary (physical exercise) and a 35-day fattening period were applied. The animals were divided into 8 groups, each including 40 animals according to temparature (C: 25 °C and SC: 37 °C) and dietary doses (C, 200, 400 and 600). Each group was divided into 4 subgroups, each comprising 10 animals. The consequences of this study showed that, in the stress-free (HSF) groups, while all of the different doses of dietary MOEO positively affected growth performance, feed intake and feed efficiency, in the HS groups, similar positive effects were observed with the use of 200 ppm of dietary MOEO. While no effect was detected on internal organ weights on Days 21 and 42 in the HSF and HS groups, a dose-dependent increase was determined in the intestinal pH value on day 42 in the HS group (p <.05). Additionally, in the analysis of meat quality on the 21st and 42 days compared to the controls, no effect was observed on the meat colour parameters value and TBARS level in the HS and HSF groups. Based on the consequences of this study, it is considered that, MOEO could be used as an alternative product in poultry, at a dose of 200 ppm, to reduce the detrimental effects of HS.HIGHLIGHTS Temperature stress, performance parameters and serious problems in the health of poultry. Moringa olifera helps regulate performance parameters in poultry exposed to heat stress. Since the addition of Moringa oleifera to the diets does not affect the organ weight and meat quality in 21 and 42 days, it does not cause any negative effects for the consumer.
AtıfScopus17WoS17OpenAlex19İncele - MakaleAçık Erişim2020Scopus SJRQ2Effect of the addition of essential fatty acid mixture to the drinking water of the heat stress broilers on adipokine (Apelin, BDNF) response, histopathologic findings in liver and intestines, and some blood parameters
Bayraktar, Bülent; Tekce, Emre; Aksakal, Vecihi; Gül, Mehmet; Takma, Çiğdem; Bayraktar, Sevil; Bayraktar, Fatma Gülten; Eser, Gizem
The purpose of this study was to examine the effect of adding an essential fatty acid mixture (EOM; Eucalyptus globulus Labill, thymus vulgaris, Cymbopogon nardus, and Syzygium aromaticum) to the drinking water in the heat stress broilers on the adipokine (Apelin, BDNF) response, the histopathologic changes in liver and intestines, and some biochemical parameters. This study lasted for a total of 42days, including the physical exercise period (7days) and the fattening period (35days). A total of 400 Ross 308 male broilers (1-d-old) were randomly divided into 8 groups (50 animals per group), each of which was exposed to various conditions of temperature (C: 22°C and SC: 36°C) and treatment dose (C, 250, 500 and 750mL/1000 L). Each group was divided into 5 subgroups, each comprising 10 animals. In the stress-free groups, whereas the Apelin level linearly decreased, the BDNF level linearly increased. In histopathology, the liver tissue was found to be normal in all groups whereas the duodenum villi length was found to increase in the group of 750mL/1000 L. No statistically significant difference was found between the stressed groups and the non-stressed groups in terms of VLDL, Glucose, Total bilirubin, ALT, and TG (p >.05). While Apelin level increased in the stressed groups, the BDNF level increased in the group of 250mL/1000 L. In the histopathological examination, a small amount of coagulation necrosis was detected in hepatocyte, a diffuse hydropic degeneration was observed in hepatocytes, and finally a dilatation and hyperaemia were seen in sinusoid in the groups of EOM-500mL/1000 L and EOM-750 m/1000 L compared to the control group. Whereas there was no difference between the group of EOM-250mL/1000 L and the control group in terms of duodenum villa length, there was a significant decrease in other groups (p <.00). In conclusion, this study showed that adding 250mL/1000 L of EOM to the drinking water had a positive effect on the serum levels of Apelin and p-BDNF in the groups exposed to stress (p <.05).HIGHLIGHTS Heat stress results in serious annual economic losses in the poultry industry. Essential oil fatty mix acids have positive effects on poultry health. Apelin and BDNF may be a protective factor against deleterious consequences of chronic exposition to heat stress.
AtıfScopus12WoS9OpenAlex10İncele - MakaleAçık Erişim2020Scopus SJRQ2Phy-X / PSD: Development of a user friendly online software for calculation of parameters relevant to radiation shielding and dosimetry
Şakar, Erdem; Özpolat, Özgür Fırat; Alım, Bünyamin; Sayyed, M.I.; Kurudirek, Murat
A user friendly online Photon Shielding and Dosimetry (PSD) software available at https://phy-x.net/PSD has been developed for calculation of parameters relevant to shielding and dosimetry. These parameters include linear and mass attenuation coefficients (LAC, MAC), half and tenth value layers (HVL, TVL), mean free path (MFP), effective atomic number and electron density (Zeff, Neff), effective conductivity (Ceff) energy absorption and exposure buildup factors (EABF, EBF). The software can generate data on shielding parameters in the continuous energy region (1 keV-100 GeV). Also, some well-known radioactive sources (22Na, 55Fe, 60Co, 109Cd, 131I, 133Ba, 137Cs, 152Eu and 241Am) along with their energies and some characteristic (K-shell) X-ray energies of Cu, Rb, Mo, Ag, Ba and Tb elements are available in the software and can be selected by the user. Thus, one can obtain the shielding parameters at photon energies available for the predefined energies. Moreover, another parameter relevant to shielding i.e. the fast neutron removal cross section (FNRCS) can be calculated for a compound or a mixture using this software. The software is freely available online after having registered to the Phy-X platform.
AtıfScopus2019WoS1977OpenAlex2133İncele - MakaleYalnız künye2020Scopus SJRQ4Production of enantiopure chiral aryl heteroaryl carbinols using whole‐cell Lactobacillus paracasei biotransformation
Şahin, Engin
Aryl and heteroaryl chiral carbinols are useful precursors in the synthesis of drugs. Lactobacillus paracasei BD87E6, which is obtained from a cereal based fermented beverage, was investigated as whole cell biocatalyst for the bioreduction of different ketones (including aromatic, hetero-aromatic and fused bicyclic ketone) into chiral carbinols, which can be used as a pharmaceutical intermediate. The study shows that bioreduction of aryl, heteroaryl and fused bicyclic ketone (1–5) to their corresponding chiral carbinols (1a–5a) in excellent enantioselectivity (>99%) with high yields. This study gave the first example for an enantiopure production of (S)-6-chlorochroman-4-ol (3a), which has many antioxidant activity, by a biological method. For asymmetric bioreduction of other prochiral ketones, these results open way to use of L. paracasei BD87E6 as biocatalysts. Also, the present process shows a hopeful and alternative green synthesis for the production of enantiopure carbinols in a mild, inexpensive and environmentally friendly process.
AtıfScopus21WoS18OpenAlex20İncele - MakaleAçık Erişim2020Scopus SJRQ2A visual application for teaching pipe flow optimization in engineering curricula
Türkkan, Yusuf Alptekin; Eryılmaz Türkkan, Gökçen; Yılmaz, Hamid
The main purpose of this study is to investigate the importance of programming in the learning and understanding of water distribution networks. This paper presents the implementation of a programming language C# for applications for teaching water distribution networks calculations at both undergraduate and graduate levels. A user's guide is also prepared for the software which includes the theory of hydraulic and optimization calculations. There are many ways to design water distribution networks. Hardy Cross method is very often used for optimization of networks. Thus, Hardy Cross optimization method was preferred in this study. It is a perfect study to implement as an educational tool at undergraduate and graduate levels of education.
AtıfScopus12WoS10OpenAlex12İncele - MakaleYalnız künye2020Scopus SJRQ1Thin films derived from Zn(Al)O mixed metal oxides nanoparticles dispersed in polyethylene glycol: Structural, morphological and optical properties
El Hassani, Kaoutar; Bayram, Ozkan; Anouar, Abdellah; Mavi, Ahmet
In this study, Zn(Al)O thin films were produced using colloidal solution of Zn(Al)O nanoparticles dispersed in polyethylene glycol (PEG). Zn(Al)O mixed metal oxides were obtained by a simple pyrolysis of Zn–Al containing layered double hydroxide materials with different Al content. Survey of textural analysis of Zn(Al)O mixed oxides displayed characteristic peaks of ZnO structure. The calculated ratios of lattice parameters c/a were found to be 1.61 and 1.60 for 3-ZAO and 5-ZAO, respectively. The optical transmittance of the prepared thin films was not significantly affected by the increase in Al content; however, this increase changed the optical band gap from 3.27 eV to 3.33 eV. ZAO thin films, which are both cost-effective with good optical properties, have the potential to be an alternative to those used in many optical devices lately.
AtıfScopus4WoS3OpenAlex4İncele - MakaleYalnız künye2020Scopus SJRQ2Reading comprehension, Mathematics self-efficacy perception, and Mathematics attitude as correlates of students’ non-routine Mathematics problem-solving skills in Turkey
Öztürk, Mesut; Akkan, Yaşar; Kaplan, Abdullah
Literature that investigates the factors affecting problem-solving evaluates the cognitive and affective components, such as reading comprehension, metacognition, Mathematics anxiety, Mathematics attitude and Mathematics self-efficacy. Recently, studies have shown that Mathematics attitude and Mathematics self-efficacy as affective factors, and reading comprehension as a cognitive factor could play a crucial role in the problem-solving of middle school students. This study investigated the influence of reading comprehension skill, Mathematics self-efficacy perception and Mathematics attitude on non-routine Mathematics problem-solving skills. It is hypothesized that non-routine problem-solving skills are related to reading comprehension skills, Mathematics self-efficacy perception and Mathematics attitudes. To achieve this aim, a reading comprehension skill test, a Mathematics self-efficacy perception scale, a Mathematics attitude scale and a non-routine problem-solving skill test were applied. The instruments were completed by 362 middle school students. A correlation analysis was used to determine the relationship of variables on non-routine problem-solving skills, and the predictive effects of the predictor variables on non-routine Mathematics problem-solving skills were examined by hierarchical regression analysis. The analysis also showed that for middle-school students’ non-routine Mathematics problem-solving skills, all related factors–reading comprehension, Mathematics self-efficacy perception and Mathematics attitude were significant. Reading comprehension skills and Mathematics self-efficacy perception significantly predicted problem-solving skills, and both predictors explained a total of 22% of the total variance.
AtıfScopus55WoS30OpenAlex116İncele - MakaleAçık Erişim2020Scopus SJRQ2Experimental investigation of radiation shielding performances of some important AISI-coded stainless steels: Part I
Alım, Bünyamin; Şakar, E.; Baltakesmez, Ali; Han, İbrahim; Sayyed, M.I.; Demir, Lütfü
The investigation of radiation shielding performances of AISI-302, 304, 321 and 430 stainless steels which have wide range of application because of their superior mechanical properties, temperature and corrosion resistances was aimed in this study. In accordance with this purpose, photon-shielding parameters of these stainless steels were calculated both experimentally and theoretically. These parameters calculated are linear attenuation coefficient, mass attenuation coefficient, mean free path, half-value layer, quarter-value layer, tenth-value layer, total atomic cross-section, total electronic cross-section, effective atomic number, effective electron number and effective conductivity. They were experimentally measured at twenty-three different energies in the range 22 keV and 1333 keV. The photon energies were obtained from seven different radioactive sources (22Na, 60Co, 241Am, 109Cd, 137Cs, 152Eu and 133Ba). The Si(Li) and NaI(Tl) detectors were separately used taking into account of energy-efficient regions to counting process at narrow-beam transmission geometry. In addition, all these parameters were computed at the 15 keV‒15 MeV wide energy range, theoretically. In order to make a satisfying assessment about radiation shielding capabilities of AISI 302, 304, 321 and 430 alloys, all calculations were also made for ordinary, steel-scrap and steel-magnetite concretes (Fe-based steel concretes) that are most commonly used as shielding material in many nuclear applications. According to the results obtained, it was observed that the radiation shielding performances of AISI 300 austenitic stainless steel series with containing Ni are superior to that of both AISI 430 ferritic stainless steel and examined concretes.
AtıfScopus52WoS46OpenAlex57İncele - MakaleAçık Erişim2020Scopus SJRQ2Investigation of the solution for discontinuous contact problem between a functionally graded (FG) layer and homogeneous half-space
Öner, Erdal; Birinci, Ahmet
In this study, the discontinuous contact problem between a functionally graded (FG) layer, which is loaded symmetrically with point load P through a rigid block, and a homogeneous half-space was solved using the theory of elasticity and integral transform techniques. The shear modulus and density of the layer addressed in the problem vary with an exponential function along with its height. The half-space is homogeneous, and no binder exists on the contact surface containing the FG layer. In the solution, the body force of the FG layer was considered, whereas that of the homogeneous half-space was neglected. The Poisson’s ratios of both the FG layer and homogeneous half-space were assumed to remain constant. Additionally, all the surfaces addressed in the problem were assumed to be frictionless. Using the theory of elasticity and integral transform techniques, the discontinuous contact problem was reduced to two integral equations, wherein the contact stress under the rigid block and the slope of the separation, which occurred at the interface of the FG layer and homogeneous half-space, are unknown. These integral equations were solved numerically for the flat condition of the rigid block profile using the Gauss–Chebyshev integration formula. Consequently, the stress distributions, start–end points of the separation region, and separation displacements between the FG layer and homogeneous half-space were obtained for various dimensionless quantities.
AtıfScopus24WoS25OpenAlex23İncele - MakaleYalnız künye2020Scopus SJRQ2Recovery of unburned carbonaceous matter (UCM) from sugar mill bottom ash
Katircioglu-Bayel, Diler; Serencam, Hüseyin; Uçurum, Metin
Millions of tons of coal fly and bottom ash are produced each year in many countries including Turkey. Coal combustion which is the main source of energy in sugar mill and many other industries produce massive quantities of waste. The present study aims to separate the unburned carbonaceous matter (UCM) from the bottom ash of Bor, Nigde-Turkey sugar plant has been studied using the mechanical flotation technique. For this purpose, the performances of three classical oils were investigated and then chemical parameters such as sodium silicate (Na2SiO3), collector (fuel-oil) and frother (pine-oil) were systematically examined by using Yates’ statistical technique. A product with 41.58% combustible grade at 87.44% recovery was obtained at 0 g/t sodium silicate, 7464 g/t fuel-oil, 888 g/t pine-oil, 15% pulp density, 1200 rpm impeller speed and natural pH. The results obtained from the experiments indicated that it was possible to enrich the bottom ash by using conventional flotation.
- MakaleYalnız künye2020Scopus SJRQ1Comparison of phenol removal with ozonation in jet loop reactor and bubble column
Barlak, Melahat Semin; Degermenci, Nejdet; Cengiz, Ibrahim; Ucun Özel, Handan; Yildiz, Ergun
This study aimed to remove phenol with ozonation in a jet loop reactor (JLR) and a bubble column (BC). In the first stage of the study, the mass transfer properties of JLR were determined and superiority over BC reactors were shown, and in the second stage, these reactors were used in phenol removal studies. At the same conditions, the volumetric mass transfer coefficient of JLR was 0.540 min-1, while this value was determined as 0.246 min-1 in the BC reactor. In phenol removal, the effects of initial phenol concentration, ozone dosage and pH on phenol and chemical oxygen demand (COD) removal were determined for both JLR and BC. While the pseudo-first rate constant for phenol removal in JLR at 221 mg/min ozone dosage was 0.1756 min-1, this value was only calculated as 0.1157 min-1 in the BC reactor. As a result, it has been shown that JLRs can achieve higher ozone gas transfer with lower energy consumption and perform more effective phenol and COD removal than BC reactors, especially at low pH and high ozone dosages.
AtıfScopus40WoS36OpenAlex39İncele - MakaleYalnız künye2020Scopus SJRQ3A dynamic segregation test method for heavyweight concrete: Density variation method
Süleyman Gökçe, H.; Andiç-Çakir, Ö.
Several segregation evaluation methods have been developed for concrete; however, none of them have been specially focused on heavyweight concrete, which has more of a tendency toward segregation because of differences in density of paste matrix to heavy aggregate. Thus, for heavyweight concrete, the segregation may be determined by measuring the difference density in a vertical direction. In this study, a simple reliable method, i.e., the density variation method, that considers the variation in vertical layers of the concrete is modeled to assess dynamic segregation of heavyweight concrete. In addition, 35 heavyweight concrete mixtures with high consistency were designed with various mixing parameters, and the results were compared with the model findings. The suggested test method was also compared with a conventional method (column segregation test by wet-sieving), and an equivalent segregation limit was determined. A strong linear relation (R2: 0.86) was found between the density variation method and column segregation test, and a segregation coefficient limit for segregation of heavyweight concrete is recommended as 1.7 %.
AtıfScopus7WoS6OpenAlex6İncele - MakaleYalnız künye2020Scopus SJRQ3First green synthesis of (R)-2-methyl-1-phenylpropan-1-ol using whole-cell Lactobacillus paracasei BD101 biotransformation
Şahin, Engin
Green chemistry includes a novel process in the production of drugs precursors and biological active molecules using biocatalysts, so reducing the threats for human sanitary and ecological pollutions. Asymmetric bioreduction of prochiral ketones by biocatalysts is one of the best prevalent used methods in synthetic organic chemistry due to the production of enantiopure chiral carbinols. This study emphasizes the application biocatalyst L paracasei BD101 for enantioselective bioreduction of 2-methyl-1-phenylpropan-1-one ketone, which contain branched alkyl chain, to (R)-2-methyl-1-phenylpropan-1-ol ((R)-2) in high yields and excellent enantiomeric excess (>99%). The scale-up production was performed, and 4.61 g of (R)-2 in enantiopure form was synthesized. L paracasei BD101 was proved to be a substantial biocatalyst in asymmetric bioreduction of a ketone which contains a branched alkyl chain. There is not any work in the literature similar to our study. Hence, it is important to work on filling this gap. This study is the first example for an enantiopure synthesis of (R)-2 by a biocatalyst. The new green method was developed for bioreduction of bulky ketones, which contains a branched alkyl chain, and it approves the synthesis of novel chiral carbinols in an easy, cheap, and environmentally friendly condition using L paracasei BD101.
AtıfScopus10WoS9OpenAlex10İncele - MakaleAçık Erişim2020THERMAL ANALYSIS OF LONGITUDINAL A POROUS FIN WITH TEMPERATURE-DEPENDENT INTERNAL HEAT GENERATION USING THE VARIATION OF PARAMETERS METHOD
Güngör, Osman; Arslantürk, Cihat
. The present study investigates the thermal performance of longitudinal a porous fin with temperature-dependent internal heat generation. The Darcy model is utilized to obtain the differential form of the governing equation that solves the nonlinear temperature distribution equation using the method of variation of parameters. Although this method is applied to solve both linear and nonlinear differential equations, there exist rare applications of this method to solve nonlinear heat transfer problems. In the present study, we applied the method to estimate the thermal analysis of the porous fin exposed to convection. The heat generation is assumed as a function of temperature. The effects of the convection parameter Nc, internal heat generation ε, porosity Sn and generation number G parameter on the dimensionless temperature distribution are discussed in detail. The accuracy of the variation of parameters method is verified through comparison with homotopy perturbation method and the Matlab bvp4c solver (NUM). The results have disclosed that the variation of parameters method can be used as a very effective and practical approach for further studies of the porous medium.
AtıfOpenAlex1İncele - MakaleYalnız künye2020Scopus SJRQ1Characterisation of physicochemical, microbiological, thermal, oxidation properties and fatty acid composition of butter produced from thermosonicated cream
Sert, Durmuş; Mercan, Emin
The effects of thermosonication of cream on physicochemical, microbiological, thermal, oxidation properties and fatty acid composition of butter were determined. Butter samples were produced from cream thermosonicated (TS) for 5, 10, or 15 min and from raw (R) and pasteurised (P) cream as controls. Thermosonication decreased moisture content, water activity, and pH of samples when compared with control groups. Mean particle size (D [3.2]) values of TS samples were lower than the R and P samples. Thermosonication improved spreadability compared with that of butter from pasteurised cream. Oxidative stability (induction time) of TS samples was lower than R, but higher than P. Two melting peaks were determined; in all samples, the Tonset of the first peak ranged from 11.39 to 11.93 °C, and the Tpeak was between 14.01 and 14.14 °C. Thermosonication significantly reduced total bacteria count and can improve spreadability, oxidative stability, and microbial safety of butter samples.
AtıfScopus27WoS22OpenAlex26İncele