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
- MakaleAçık Erişim2022Scopus SJRQ2Probiotic ice cream with Malus floribunda fruit sauce: Quality properties, mineral, and volatile composition
Arslaner, Ayla; Salik, Mehmet Ali
This study investigated the effect of Malus floribunda fruit sauce (MFS) on the quality properties, minerals, volatiles, and viability of Lactobacillus acidophilus La-5® in probiotic ice creams. The MFS increased the dry matter, acidity, total sugar, invert sugar, and calories while decreasing fat, protein, ash, sucrose contents, viscosity, overrun, first dripping, complete melting time, and the pH of samples. The heavy metal contents were within safe limits. The MFS increased the perception of a fruity taste/aroma due to the increase in the terpenes and terpenoids, which reflected positively on the sensory scores. The highest taste and odor score (4.72) was seen in the MFIC sample. L. acidophilus La-5® counts (7.49 log cfu/g) and the survival rate (100.69%) of MFIC were significantly higher at the end of storage. Consequently, MFS may be used as a source of flavoring agents in ice cream and MFIC is a satisfactory vehicle for L. acidophilus La-5®. Novelty impact statement: There is no study in the scientific literature on the use of Malus floribunda fruit sauce (MFS) as a potential functional ingredient in probiotic ice cream production. MFS supplementation caused a significant change of volatile compounds in ice cream samples, which reflected positively on the sensory scores. MFS enhanced survival rates of Lactobacillus acidophilus La-5® in ice creams during the 60 days of storage.
AtıfScopus7WoS6OpenAlex10
İncele - MakaleAçık Erişim2022Scopus SJRQ3Comparison of Bomaplex Blue CR-L Removal by Adsorption Using Raw and Activated Pumpkin Seed Shells
Irdemez, Şahset; Özyay, Gizem; Ekmekyapar Torun, Fatma; Kul, Sinan; Bingül, Züleyha
In this study, removal of colour from wastewaters prepared synthetically using Bomaplex Blue CR-L was investigated using raw and activated pumpkin seed shells by adsorption in a batch system. The effects of stirring speed, adsorbent concentration, dye concentration, temperature and pH on colour removal were investigated, and adsorption capacities of raw and activated pumpkin seed shells were determined. In addition, adsorption kinetics, isotherm coefficients, activation energies and thermodynamic parameters were calculated. The optimal adsorption conditions were determined as pH = 2, stirring speed of 200 rpm, adsorbent concentration of 10 g L-1 and 30 °C. Under the optimal conditions, the maximum removal efficiency of Bomaplex Blue CR-L using raw pumpkin seed shells was 73.01 %. This value rose to 79.71 % after activation processing was applied. Experimental adsorption data show that the adsorption is more suited to the Langmuir adsorption model and works in accordance with the pseudo-first-order kinetics model. As a result of thermodynamic research, ΔH° and ΔS° were 31.515 kJ mol-1 and 109.952 kJ mol-1 K-1 for the raw adsorbent, respectively. For the activated adsorbent, ΔH° and ΔS° were 43.118 kJ mol-1 and 152.237 kJ mol-1 K-1, respectively. The activation energy of adsorption was calculated as 10.918 kJ mol-1 for the raw adsorbent and 9.882 kJ mol-1 for the activated adsorbent.
AtıfScopus9WoS7OpenAlex9İncele - MakaleAçık Erişim2022Scopus SJRQ2Extraction of low-dimensional features for single-channel common lung sound classification
Engin, M. Alptekin; Aras, Selim; Gangal, Ali
In this study, feature extraction methods used in the classification of single-channel lung sounds obtained by automatic identification of respiratory cycles were examined in detail in order to extract distinctive features at the lowest size. In this way, it will be possible to design a system for the detection of lung diseases, completely autonomously. In the study, automatic separation and classification of 400 respiratory cycles were performed from the single-channel common lung sounds obtained from 94 people. Leave one out cross validation (LOOCV) was used for the calibration and validation of the classification model. The Mel frequency cepstrum coefficients (MFCC), time domain features, frequency domain features, and linear predictive coding (LPC) were used for classification. The performance of the features was tested using linear discriminant analysis (LDA), k-nearest neighbors (k-NN), support vector machines (SVM), and naive Bayes (NB) classification algorithms. The success of combinations of features was explored and enhanced using the sequential forward selection (SFS). As a result, the best accuracy (90.14% in the training set and 90.63% in the test set) was acquired using the k-NN for the triple combination, which included the standard deviation of LPC and the standard deviation and the mean of MFCC. Graphical abstract: [Figure not available: see fulltext.]
AtıfScopus15WoS9OpenAlex14
İncele - MakaleAçık Erişim2022Scopus SJRQ2PRE-SERVICE SCIENCE AND COMPUTER TEACHERS’ VIEWS ON TEACHING PRACTICE COURSES
Bulut, Ayhan; Kaban, Abdullatif; Bilen, Ömer
The Teaching Practice course taught in Education Faculties gives pre-service teachers real experience before starting the profession. This study aims to examine the teaching practice courses in the undergraduate programs of education faculties by the views of pre-service science and computer teachers. 50 4th grade students, 25 from the science education department and 25 from the computer and instructional technology education department, participated in the study. Within the scope of the study, the data were collected through online interviews of approximately 30 minutes with the participants, and content analysis was made. According to the findings, pre-service teachers believe that teaching practice courses are insufficient to ensure active participation in lessons in terms of learning gains and content and that they lack a flexible structure that allows them to participate in classes at various grade levels. They also stated that the teaching practice course includes result-oriented measurement and evaluation activities. However, they underlined that the semesters and credits allocated to undergraduate teaching practice courses are insufficient. Furthermore, throughout the process, pre-service teachers reported some communication and coordination issues in the teaching practice course. They suggested that every university with an education faculty should open practice schools that include all levels of compulsory education to overcome the challenges encountered during the process.
AtıfScopus1WoS1İncele - MakaleAçık Erişim2022Scopus SJRQ3Comparison of Serum Adropin Levels in Patients with Diabetes Mellitus, COVID-19, and COVID-19 with Diabetes Mellitus
Aydın, Pelin; Karabulut Uzunçakmak, Sevgi; Tör, İbrahim Hakkı; Bilen, Arzu; Özden, Ayşe
Objective: In the present study, the relationship between a poor prognosis and adropin levels in diabetic patients with coronavirus disease 2019 was investigated by measuring serum adropin levels and levels of D-dimer, C-reactive protein, and ferritin, which are considered prognostic factors for coronavirus disease 2019. Materials and Methods: Hundred volunteer participants treated in the Erzurum Regional Training and Research Hospital were included in this study. Serum adropin levels were measured by enzyme-linked immunosorbent assay. The relationship between serum adropin level and C-reactive protein, ferritin, and D-dimer levels was analyzed by correlation analysis. Results: The participants’ serum adropin levels differed between the groups (P =.0007). The control group had the highest adropin levels among groups. The lowest adropin levels were in the COVID + diabetes mellitus group. Adropin levels of diabetes mellitus, COVID, and diabetes mellitus + COVID groups were significantly decreased when compared to the control (P <.05). There was a significant negative correlation between adropin and C-reactive protein, D-dimer, and ferritin. Conclusion: Adropin can be used as an auxiliary biomarker, a prognostic factor in the early management of coronavirus disease 2019 patients with diabetes mellitus. We think that our study will guide future studies conducted in this field.
AtıfScopus9WoS10OpenAlex13TR Dizin3
İncele - MakaleAçık Erişim2022Scopus SJRQ3An investigation of mathematics teachers' specialized content knowledge related to basic concepts about sets
Yazici, Nurullah; Albayrak, Mustafa
This research was carried out in order to examine the specialized content knowledge of mathematics teachers related to teaching basic concepts about sets within the MKT Model. In this study, a holistic single-case study design is used in qualitative research methods. The study group consists of 18 mathematics teachers at different educational background and professional experience in teaching sets selected through the sampling of criterion, which is working in different high schools in one province in the Mediterranean region in the academic year 2016-2017. Research data were obtained using semi-structured interview, observation and document analysis techniques. In the analysis of obtained data, descriptive analysis, content analysis, continuous comparison techniques and special data analysis methods were used together with each data collection tool. The findings of the research show that teachers gave correct answers to the questions asked about the basic concepts of "Why?" in the sets. However, it is clear that the teachers cannot write sufficient reason why the asked questions are "Why?". As a result of the research, it has been determined that the teachers have superficial knowledge about the concepts of "Set, Universal Set, Infinite Set" and "Equal Set". However, it was determined that teachers made explanations with a general mathematical knowledge based on the characteristics of the concept rather than providing persuasive mathematical explanations to the questions asked.
AtıfOpenAlex1TR Dizin1İncele - MakaleYalnız künye2022Scopus SJRQ1Structural and bioactive characteristics of a dextran produced by Lactobacillus kunkeei AK1
Yilmaz, Mustafa Tahsin; İspirli, Hümeyra; Taylan, Osman; Bilgrami, Anwar L.; Dertli, Enes
In this study, structural and techno-functional characteristics of an exopolysaccharide (EPS) produced by Lactobacillus kunkeei AK1 were determined. High-performance liquid chromatography (HPLC) analysis demonstrated that EPS AK1 was composed of only glucose units. 1H and 13C Nuclear magnetic resonance (NMR) analysis revealed that EPS AK1 was a dextran type EPS containing 4.78% (1 → 4)-linked α-D-glucose branches. The molecular weight of EPS AK1 was determined to be 45 kDa by Gel Permeation Chromatography (GPC) analysis. A high level of thermal stability up to 280 °C was determined for dextran AK1 detected by Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA). Dextran AK1 appeared as regular spheres with compact morphology and as irregular particles in the solution with no clear cross-linking between the chains of the polysaccharide observed by Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) analysis, respectively. X-ray diffraction analysis (XRD) analysis demonstrated that dextran AK1 had a crystalline structure. A relatively strong antioxidant activity was observed for dextran AK1 determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging and cupric reducing antioxidant capacity (CUPRAC) tests. Finally, only a digestion ratio of 3.1% was observed for dextran AK1 following the in vitro simulated gastric digestion test.
AtıfScopus43WoS39OpenAlex41İncele - MakaleYalnız künye2022Scopus SJRQ3Biocatalytic asymmetric synthesis of (S)-1-indanol using Lactobacillus paracasei BD71
Kalay, Erbay; Dertli, Enes; Şahin, Engin
Enantiopure benzo-fused cyclic alcohols have been used as a building block of a drug for Parkinson’s disease. Biocatalytic reduction of ketones is one of the most promising and significant routes to prepare optically active alcohols. In this study, the reductive capacity of seven lactic acid bacteria (LAB) strains were investigated as whole-cell biocatalyst in the enantioselective reduction of 1-indanone (1). Lactobacillus paracasei BD71 was found to have the best reductive capacity. Effects of different parameters such as pH, incubation time, agitation speed and temperature, on enantiomeric excess (ee) and conversion were investigated in a bioconversion. (S)-1-indanol ((S)-2) could be used as precursor for the synthesis of rasagiline mesylate TVP1012 for the therapy of Parkinson’s illness. It was produced in gram-scale (5.24 g), high yield (93%) and enantiomerically pure form using L. paracasei BD71 whole-cell biocatalysts. Also, to our knowledge, this is the first report on production of (S)-2 using whole-cell catalyst in enantiopure form, excellent yield, conversion and gram scale. This is a cheap, clean and eco-friendly process for production of (S)-2 compared to chemical processes.
AtıfScopus6WoS6OpenAlex6İncele - MakaleYalnız künye2022Scopus SJRQ3Optimization of asymmetric reduction conditions of 1-(benzo [d] [1,3] dioxol-5-yl) ethanone by Lactobacillus fermentum P1 using D-optimal experimental design-based model
Özdemir, Akın; Dertli, Enes; Şahin, Engin
The biocatalytic asymmetric reduction of prochiral ketones is a significant transformation in organic chemistry as chiral carbinols are biologically active molecules and may be used as precursors of many drugs. In this study, the bioreduction of 1-(benzo [d] [1,3] dioxol-5-yl) ethanone for the production of enantiomerically pure (S)-1-(1,3-benzodioxal-5-yl) ethanol was investigated using freeze-dried whole-cell of Lactobacillus fermentum P1 and the reduction conditions was optimized with a D-optimal experimental design-based optimization methodology. This is the first study using this optimization methodology in a biocatalytic asymmetric reduction. Using D-optimal experimental design-based optimization, optimum reaction conditions were predicted as pH 6.20, temperature 30 °C, incubation time 30 h, and agitation speed 193 rpm. For these operating conditions, it was estimated that the product could be obtained with 94% enantiomeric excess (ee) and 95% conversion rate (cr). Besides, the actual ee and cr were found to be 99% tested under optimized reaction conditions. These findings demonstrated that L. fermentum P1 as an effective biocatalyst to obtain (S)-1-(1,3-benzodioxal-5-yl) ethanol and with the D-optimal experimental design-based optimization, this product could be obtained with the 99% ee and 99% cr. Finally, the proposed mathematical optimization technique showed the applicability of the obtained results for asymmetric reduction reactions.
AtıfScopus6WoS6OpenAlex7İncele - MakaleYalnız künye2022Scopus SJRQ1Comparison of the probiotic characteristics of Lactic Acid Bacteria (LAB) isolated from sourdough and infant feces
Kaya, Yasemin; Erten, Tayyibe; Vurmaz, Melike; İspirli, Hümeyra; Şimşek, Ömer; Dertli, Enes
Probiotics are beneficial microorganisms with certain characteristics such as survival under gastrointestinal conditions, adhesion to intestinal surface and different functions which result in several health benefits to host. With this regards, this study aimed to isolate Lactic Acid Bacteria (LAB) from sourdough and human feces as two different environments and to test their potential probiotic functions. In total nine distinct isolates were assessed with several probiotic functions such as in vitro adhesion to human colon cells, antimicrobial activities and survival under harsh gastrointestinal conditions. In general, distinct strains showed strong antimicrobial activity against the pathogenic and fungal strains tested in this study. Importantly, the adhesion levels to HT29 cells were determined between 0.29 % and 9.54% and Lactobacillus paracasei F7B showed the highest adhesion. All isolates tolerated the bile salt after 24 h and the infant feces isolates showed good survival characteristics at pH 4.
AtıfScopus18WoS15OpenAlex18İncele - MakaleYayıncıda açık erişim2022Scopus SJRQ3EFFECTS OF MOLAR RATIO, FREQUENCY, WATER CONTENT AND TEMPERATURE ON DIELECTRIC PROPERTIES OF DEEP EUTECTIC SOLVENTS
Kutlu, N.; Yilmaz, M.S.; Erdem, G.M.; Sakiyan, O.; Isci, A.
The aim of the study is to determine the effect of process parameters on dielectric propertiesof deep eutectic solvents (DESs), which have beenwidely used in recent years. In this study, DESs wereprepared using choline-chloride as the hydrogenbondacceptor and glycerol, formic acid and aceticacid as the hydrogen-bond donor. The effect of differentprocess parameters such as molar ratio (1:2, 1:3and 1:4), water content (15%, 30% and 45%), temperature(25, 50 and 75 °C) and frequency on dielectricproperties of the DESs were examined. The highestdielectric constant values were found to be38.13±0.54, 44.96±0.07 and 46.74±0.02 for glycerol,formic acid and acetic acid, respectively for the processconditions of 25 °C temperature, 45% water contentand 1:4 molar ratio (at 2450 MHz). Moreover, forall DESs, it was found that a decrease in water contentresulted in a decrease in both dielectric constant andloss factor values. This can be explained by the absenceof free water molecules which are responsiblefrom dipole rotation mechanism. In light of the results,if DES will be used in microwave processes, formicor acetic acid containing DESs might give moresuccessful results compared to the ones with glycerol
AtıfScopus7WoS6OpenAlex8İncele - MakaleAçık Erişim2022Scopus SJRQ1Calibration-Free Time-Domain Free-Space Permittivity Extraction Technique
Hasar, Ugur C.; Ozturk, Gokhan; Kaya, Yunus; Ertugrul, Mehmet
A time-domain free-space technique has been proposed to extract relative permittivity ( _r ) and effective conductivity ( σ _e ) of low-loss dielectric samples using their metal- and air-backed calibration-free reflected powers. Numerical computations and 3-D electromagnetic simulations were performed to validate the method. A sensitivity analysis was carried out to examine its accuracy. Calibration-free time-domain free-space measurements over 1-12 GHz were conducted by VNA to extract _r and σ _e of polyethylene and polypropylene low-loss samples.
AtıfScopus29WoS28OpenAlex29İncele - MakaleYalnız künye2022Scopus SJRQ2A study on the effects of nanostructure reinforcement on the failure load in adhesively bonded joints after the subjected to fully reversed fatigue load
Akpinar, Salih; Demir, Kübra; Gavgali, Esma; Yetim, Ali Fatih
Today, adhesively bonded joints are frequently used in the space and aviation industries. Joints used in these sectors are generally subject to dynamic loads due to environmental factors. This study experimentally and numerically investigated the static tensile loads of adhesively bonded joints after fully reversed (combination of tensile and compressive) fatigue loading where nanoadhesives–obtained by adding carbon nanostructures into aerospace grade structural adhesive–were used to bond the joints. Single lap joint specimens were produced using a nanocomposite adhesive obtained by adding 1 wt. % graphene, 1 wt. % carbon nanotubes-COOH and 1 wt. % fullerene C60 nanostructures to a DP460 structural adhesive. AA2024-T3 aluminum alloy and carbon fiber-reinforced composites (CFRCs) with a plain weave fabric (0/90°) were used as adherend materials. First, static tensile tests were applied to these joints to obtain their failure loads and then fully reversed sinusoidal fatigue tests were applied under a constant load amplitude, a frequency of 20 Hz and a load ratio of R = −1. Considering the failure loads obtained from the static tensile tests, 106 fully reversed fatigue loading cycles were applied–which was accepted as an infinite life–at 400 N, 800 N and 1200 N load levels. The static tensile failure loads and energy values absorbed of these joints were obtained and the change in the failure loads and energy values absorbed of the joints subjected to fatigue was investigated. The static failure loads of aluminum joints bonded with nanoadhesive and subjected to fully reversed fatigue loading increased by approximately 5% to 17%, depending on the nanostructure type added to the adhesive. Moreover, it was observed that there was an increase in loading of approximately 3% to 20% for the nanostructure reinforced joints obtained by using CFRCs with [0/90]6 stacking sequence.
AtıfScopus24WoS26OpenAlex28İncele - MakaleAçık Erişim2022Scopus SJRQ2A novel internal curing method for 3D-printed geopolymer structures reinforced with a steel cable: Electro-heating
Gökçe, H.S.; Güngör, O.; Öksüzer, N.
Buildability and structural integrity are the inherent challenges of 3D printed geopolymer structures needed to be overcome. Reinforcing with steel cable ensuring a higher structural integrity of the printed structure can simultaneously improve the buildability due to the heating capability of this component. The controllable instant heating capability of steel cable was achieved by the use of a specific circuit system in the study. As a novel internal curing technique, electro-heating is recommended in the additive manufacturing of steel cable-reinforced geopolymer structures by the authors.
AtıfScopus4WoS3OpenAlex5İncele - MakaleAçık Erişim2022Scopus SJRQ2Assessment of waste-to-energy potential of ELT management: An actual case study for Erzincan
Güngör, Osman; Tozlu, Alperen; Arslantürk, Cihat
End-of-life tires (ELTs) and their decomposition are becoming a major environmental issue in the local region as a result of economic and technological challenges. Despite this, ELT management is gaining popularity as an advanced function for treating tires to obtain char, oil, and gas products using pyrolysis. The main goal of this article is to integrate data from an actual recycling plant with the activities of pyrolysis products and their physical properties in the literature. This article presents energy potentials and basic applications of pyrolysis products as well as advances in the current situation in ELT management in the world. Accordingly, an existing ELT management in Erzincan, Turkey is explained in detail by considering the available energy recovery and material treatment activities. In this plant, which has an installed power capacity of 12 MW, approximately 25 tons of pyrolytic oil, 10.7 tons of pyrolytic gas, 24 tons of carbon black and, 10.4 tons of steel are produced daily. The calorific values of carbon black and pyrolytic oil for the products leaving the pyrolysis plant are close to the values in the literature, which is promising. In the plant, the overall thermal efficiency of the system and the engine is found to be 26.34% and 51.24%, respectively. On the other hand, to supply additional power to the plant utilizing exhaust gas discharged to the atmosphere, some thermodynamic models can be developed; additionally, more rational values can be obtained through thermoeconomic and optimization.
AtıfScopus1WoS2OpenAlex3İncele - MakaleAçık Erişim2022Scopus SJRQ1Grey Zone: A Gap between Heavy and Severe Exercise Domain
Ozkaya, Ozgur; Balci, Gorkem Aybars; As, Hakan; Cabuk, Refik; Norouzi, Mahdi
The aim of this study was to determine a critical threshold (CT) interpreted as “the highest exercise intensity where V̇O2 can be stabilized before reaching 95% of V̇O2max (V̇O2peak)” and compare it with commonly used anaerobic threshold indices. Ten well-trained male cyclists volunteered for this study. Ventilatory threshold (VT) was determined from incremental tests. Multisession constant-load trials were performed to reveal V̇O2max. Mathematically modeled critical power (CP) was estimated through the best individual fit parameter method. Maximal lactate steady state (MLSS) was detected by 30-minute constant-load exercises. The individual CT load of each cyclist was tested by constant-load exercises to exhaustion with +15 W intervals until minimal power output to elicit V̇O2peak. The results showed that work rate corresponding to CT (329.5 6 41.5 W) was significantly greater than that of the MLSS (269.5 ± 38.5 W; p = 0.000), VT (279.6 ± 33 W; p = 0.000), and CP (306.3 ± 39.4 W; p = 0.000), and CP overestimated both VT and MLSS (p = 0.000). There was no significant V̇O2 difference between the 10th and 30th minute of MLSS and MLSS + 15 W exercise (0.36–0.13 ml·min-1·kg-1; p = 0.621). Exercising V̇O2 response of MLSS + 15 W could not exceed the level of 95% V̇O2max (57.02 ± 3.87 ml·min-1·kg-1 and 87.2 ± 3.1% of V̇O2max; p = 0.000), whereas V̇O2 responses greater than 95% of V̇O2max were always attained during exercises performed at CT + 15 W (64.52 ± 4.37 ml·min-1·kg-1 and 98.6 6 1% of V̇O2max; p > 0.05). In conclusion, this study indicates that there is a “grey zone” between heavy and severe exercise domain. This information may play a key role in enhancing athletic performance by improving the quality of training programs.
AtıfScopus21WoS19OpenAlex27İncele - MakaleAçık Erişim2022Scopus SJRQ1Thermoeconomic analysis of a low-temperature waste-energy assisted power and hydrogen plant at off-NG grid region
Tozlu, Alperen; Kayabasi, Erhan; Ozcan, Hasan
In this study, thermoeconomic analysis of a CO2 power cycle and PEM hydrogen system using ultra-low temperature waste heat from a milk production facility is conducted. In the transcritical CO2 cycle, low-temperature LNG evaporation is used for cooling the condenser to increase the temperature difference enabling low temperature waste heat use. In addition, a PEM electrolyzer produces hydrogen to reduce the LNG requirement at the plant. A CO2-water exchanger has been designed to recover the pasteurized water's excess heat and evaporate the CO2 using Simcenter-Flomaster software. The inlet mass flow rates and outlet temperatures of the heat exchanger were optimized by performing thermoecomic analysis, and the thermal and economic performance of the facility was examined. The power cycle has 14% higher efficiency when LNG is used as the heat sink compared to ambient temperature condensation with an electricity production cost range at 0.05–0.11 $/kWh, and the hydrogen generation cost is between $2.6–5.20 kg−1. It is found that the plant could only be economically feasible when less than 50% of the power produced is used for hydrogen generation. Consequently, the proposed system can co-generate power and on-demand hydrogen in off-NG grid regions with reasonable investment and product costs.
AtıfScopus6WoS6OpenAlex8İncele - MakaleAçık Erişim2022Scopus SJRQ3Investigation of biological activities of plant extract and green synthesis silver nanoparticles obtained from Gilaburu (Viburnum opulus L.) fruits
Şahin, Birgütay; Bülbül, Ali Savaş; Çelik, I. Seyfettin; Korkmaz, Nesrin; Karadağ, Ahmet
In this study, biological activities of silver nanoparticles (AgNP) synthesized by green synthesis method using the fruit extract of Gilaburu (Viburnum opulus L.) plant were investigated. The characterization of the synthesized AgNPs was performed by ultraviolet visible region spectroscopy (UV-Vis), Fourier transform - infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques. The crystal size was found to be 52.32 nm when the XRD data were calculated with the Debye-Scherrer's equation. The antimicrobial activities of extract and AgNPs were investigated by microdilution and disk diffusion methods. Antibiofilm activities were examined by the crystal violet technique. The cytotoxic effects of the extract and AgNPs against MCF-7 (human breast cancer) and HUVEC (human umbilical vein endothelial cells) cell lines were evaluated by MTT assay. The IC50 values for the HUVEC line were found to be 0.97 mg/mL (AgNP) and 85.24 mg/mL (extract), while the IC50 values for the MCF-7 line were determined as 0.022 µg/mL (AgNP) and 0.021 µg/mL (extract). To our knowledge, this is the first report to comprehensively examine the biological activities of V. opulus L. extract and biosynthetic AgNPs.
AtıfScopus11WoS11OpenAlex10TR Dizin1İncele - MakaleAçık Erişim2022Scopus SJRQ1Eumelanin protects the liver against diethylnitrosamine-induced liver injury
Altındağ, Fikret; Boğokşayan, Seda; Bayram, Sinan
This study aims to evaluate in vivo protective effects of eumelanin (EU) on diethylnitrosamine (DEN)-induced liver injury. Wistar albino male rats were divided into 6 groups (n = 6), Control, DMSO, DEN, DEN + EU10, DEN + EU15, and DEN + EU20. Animals in the DEN group were injected i.p a single dose of 200 mg/kg DEN, DEN + EU10 group was given 10 mg/kg EU, DEN + EU15 group was given 15 mg/kg, DEN + EU20 group was given 20 mg/kg EU for a week. The results showed that there was no significant difference in vessel volume density between the groups. Inflammatory cell infiltration, hydropic degeneration, and necrotic cells were observed in the DEN group, and these histopathological changes were significantly reduced in all treatment groups. Although there was a low intensity of PAS-positive staining in the DEN groups, moderate staining was observed in the treatment groups. While Caspase-3, PCNA, TNF-α, and IL-6 expressions increased in the DEN group, their expressions decreased in the EU-treated groups. DEN increased AST, ALT, and MDA levels and decreased CAT levels. In particular, the EU10 dose significantly improved these parameters. The present study revealed that eumelanin has protective effects against DEN-induced liver injury.
AtıfScopus9WoS8OpenAlex10İncele - MakaleYalnız künye2022Scopus SJRQ2Improvement of corrosion and stress corrosion properties of magnesium alloys by coating aluminum with the electric arc spray method
Catar, Recep; Altun, Hikmet
In this study, corrosion and stress corrosion behaviors of AZ31, AZ61, and AZ91 magnesium alloys coated with aluminum by the electric arc spray method were investigated in 3.5 wt.% NaCl solution. Structural properties of coated materials were investigated by scanning electron microscopy (SEM), energy dispersive X-ray analysis, and X-ray diffraction. Electrochemical properties were determined using the potentiodynamic polarization method in 3.5 wt.% NaCl solution. Potentiodynamic polarization curves showed that corrosion current density values did not change with coating in aluminum-coated samples by the electric arc spray method. In contrast, corrosion potential value increased toward positive values. Slow strain rate test (SSRT) was used to determine the stress corrosion behavior and stress corrosion indexes (ISCC), ultimate tensile strength (UTS), and elongation of AZ31, AZ61, and AZ91 magnesium (Mg) alloys were determined. As a result of the SSRT, the aluminum coating process decreased significantly the stress corrosion indexes of AZ31, AZ61, and AZ91 Mg alloys. The fracture of surface images was also examined in the SEM, and both intergranular and transgranular stress corrosion cracking were observed in all three alloys.
AtıfScopus6WoS5OpenAlex5İncele