Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Gul, Muhammet(85)
- Serdar, Osman(72)
- Güler, Ömer(68)
- Akkurt, Nevzat(61)
- Baskonus, Haci Mehmet(54)
- Alataş, Mevlüt(53)
- Paksoy, Mehmet Yavuz(53)
- Yucesan, Melih(53)
- Bulut, Hasan(51)
- Tekin, H.O.(51)
- ALMisned, Ghada(48)
- Yildirim, Numan(48)
- Benzer, Fulya(47)
- Kocabaş, Mehmet(45)
- Yildirim, Nuran Cikcikoglu(44)
- Kutlu, Banu(41)
- Ince, Muharrem(39)
- Zengin, Gokhan(39)
- Batan, Nevzat(37)
- Utku, Anıl(35)
- Celik, Erkan(33)
- Topal, Murat(32)
- Ezer, Tülay(31)
- Tanyol, Mehtap(31)
- Can, Erkan(30)
- Sulaiman, Tukur Abdulkadir(29)
- Aslan, Naim(28)
- Özkul, İskender(28)
- Aslan, Alper(27)
- Cakilcioglu, Ugur(27)
- Erguven, Gokhan Onder(27)
- Kutluyer, Filiz(27)
- Kök, Mediha(27)
- Ates, Mehmet(26)
- Erten, Fusun(26)
- Kahraman, Gökhan(26)
- Onat, Onur(26)
- Dal, Nursel Alp(25)
- Danabas, Durali(25)
- Say, Yakup(25)
Yayınlar
- MakaleYalnız künye2022Scopus SJRQ1Occupational health, safety and environmental risk assessment in textile production industry through a Bayesian BWM-VIKOR approach
Ak, M. Fatih; Yucesan, Melih; Gul, Muhammet
Occupational risk assessment (ORA) is a process that consists of evaluating, ranking, and classifying the hazards and associated risks arising in any workplace from the viewpoint of occupational health and safety. Many ORA methods have been proposed in the literature, from a single independent expert to participatory methodologies made by group decision and simple to complex ones. In this paper, a holistic ORA is presented, which uses two important multi-attribute decision methods named Bayesian Best-Worst Method (Bayesian BWM) and VIseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR). Bayesian BWM is used to determine the importance weights of six different assessment criteria, which are the probability of hazardous event (P), frequency (F), severity (S), detectability (D), cost (C) and sensitivity not to use personal protective equipment (SNP). Since the classical BWM finds solution to the weights of a number of criteria from only one expert's judgment, Bayesian BWM is preferred in this paper (1) to enable participation of a group of experts, (2) to aggregate the preferences of these multiple experts into consensus without loss of information and (3) to follow a probabilistic way for solving the ORA problem. The hazards are then ranked by VIKOR. The approach is implemented in the ORA process of a textile production plant. Results of risk analysis showed that electricity hazard and associated risks constitute the highest risk ratings. These hazards arise from the product, process, human and working environment. The associated risks are evaluated, prioritized, and detailed control measures are proposed. This study made comparisons with the classical BWM-VIKOR approach to demonstrate the proposed approach's difference and practicality. Results can also help practitioners and risk analysts in formulating the improvement measures to increase the overall safety of the working environment further.
AtıfScopus87WoS78OpenAlex87
İncele - MakaleYayıncıda açık erişim2022Scopus SJRQ2Dental Material Detection based on Faster Regional Convolutional Neural Networks and Shape Features
Imak, Andaç; Çelebi, Adalet; Türkoğlu, Muammer; Şengür, Abdulkadir
In this paper, a novel approach is proposed to detect the dental materials in dental Panoramic images. In general, dental Panoramic images are examined by the dentists to detect the dental materials of the patients. Examining the dental Panoramic images is a time-consuming procedure and necessitates highly skilled dentists. Thus, computer imaging and decision support systems based on machine learning are in demand for dental applications. In this study, a semi-automatic, image processing and machine learning based approach is proposed for detection of dental materials in dental Panoramic images. More specifically, the dental materials namely dental filling, dental bridge and tooth crown are targeted by the proposed approach. Within the approach developed, the dental Panoramic images used as input are initially pre-processed for noise removal and tooth region is determined using a deep learning approach. To this end, a faster Regional Convolutional Neural Networks (RCNN) method is employed. A tooth region correction procedure is applied after application of faster RCNN to determine the exact location of the tooth region as faster RCNN may produce more tooth regions than one correct tooth region. Graph cut (GC) based image segmentation is applied to segment the tooth region into foreground and background regions. Shape based feature extraction and classification are applied to determine the tooth problem. A dataset has been established in dental faculty hospital of private dental clinics. The proposed approach is simple yet quite effective. In all classification methods, the average accuracy scores were around 90%.
AtıfScopus9WoS7OpenAlex10İncele - MakaleAçık Erişim2022Calculation of Dynamic Properties of Drug-Added Aqueous Solutions with T1 and T2 Relaxation Times; [İlaç Katkılı Sulu Çözeltilerin Dinamik Özelliklerinin T1 ve T2 Rölaksasyon Zamanları ile Hesaplanması]
Korunur, Sibel
The development of modern spectroscopic methods has facilitated and accelerated structure analysis. The NMR method is the most popular way to perform structural analysis of compounds with very complex structures. D2O is a solvent that is frequently used in NMR analysis of both chemical molecules and many biological molecules such as drugs, proteins, and enzymes. In this paper, the study of residual water in proton drug-added protein solutions was carried out via NMR relaxation. The spin-lattice (T1) and the spin-spin relaxation (T2) times of residual water in drug-added protein solutions were studied depending on temperature by Avance Bruker 400 MHz1H-NMR Spectrometer, and activation energies (E! ) and rotational correlation times (τ" and τ# ) have been determined for T1 and T2 relaxation times.
- MakaleAçık Erişim2022Scopus SJRQ2Investigation of the effect of the life satisfaction and psychological well-being of nursing students on their happiness levels
Yeşi̇ltepe, Akgün; Sayar, Serap; Çal, Ayşe
Purpose: This study aims to examine the effect of nursing students' life satisfaction and psychological well-being on their perceived happiness levels. Method: The study, which was designed as a descriptive and cross-sectional study was carried out in Turkey with 264 students of nursing. Findings: Students' life satisfaction and happiness (r = 0.722), psychological well-being and happiness (r = 0.743), and psychological well-being and life satisfaction (r = 0.689) were found to be positively and highly correlated. Students' gender and perception of income status and general health status affected their happiness levels. It was revealed that life satisfaction and psychological well-being predict happiness (63.6%). Practice implications: The factors of life satisfaction and psychological well-being play a decisive role in the happiness of nursing students.
AtıfScopus19WoS18OpenAlex20
İncele - MakaleAçık Erişim2022Scopus SJRQ2Synthesis and characterization of N-(2-acetyl benzofuran-3-yl) methacryl amide and ethyl methacrylate copolymer/graphite oxide composites and study of their kinetic and electrical properties
Demirelli, Kadir; Barım, Esra; Tuncer, Hülya; Barım, Gamze; Abubakar, Abdullahi Musa
Copolymers of N-(2-acetylbenzofuran-3-yl) methacrylamide (BFMAA) and ethyl methacrylate (EMA) were prepared by radical copolymerization. The composition of copolymers was estimated by 1H-NMR spectroscopy. The composites of P(BFMAA39-co-EMA) [COP1] and P(BFMAA15-co-EMA) [COP2] loaded 18 wt% graphite oxide (GO) were prepared utilizing Ultrasonic Homogenizer Sonicator Processor. The FT-IR, DSC, TGA and SEM techniques were used in the characterization of the copolymers and composites. The thermal degradation behavior of COP1 was investigated by FT-IR studies of the partially degraded copolymer. And, this copolymer was able to form a four-member amide ring and imidization via intramolecular while being heated above 340 °C. Dynamic TG analysis under argon gas was used to investigate the thermal decomposition processes of pure COP1 and COP1/GO. Two degradation models including the Flynn–Wall–Ozawa and Kissinger–Akahira–Sunose methods were used to determine the apparent activation energy of the copolymer and its composite for approximately 65% of thermal decomposition occurred between 200 and 400 °C. The results also showed that average activation energy between 111.69 and 134.25 kJ/mol was obtained. The estimated activation energy values make it possible to build a simpler approach to expose the thermal decomposition behavior of copolymer and its composite. Dielectric and electrical behaviors of the copolymer composites having a semiconductor behavior filled with graphite oxide (GO) were investigated. The activation energy values of P(BFMAA15%-co-EMA)[COP2]/GO 18 wt% and COP1/GO 18wt% from dc conductivities were 0.182 eV and 0.245 eV, respectively.
AtıfScopus6OpenAlex8İncele - MakaleYalnız künye2022Scopus SJRQ2Performance evaluation of pectin extraction from grapefruit peel powder by ohmic heating
Goksu, Ali; Duran, Gülseven; Çilingir, Seda; Çevik, Mutlu; Sabanci, Serdal
This study is to investigate the performance properties during the extraction of pectin from grapefruit peel powder using ohmic heating. Pectin extraction was carried out under different voltage gradients (7–11 V/cm), different solid: liquid ratios (1:20–1:60), and different holding times (0–180 min) at constant pH and temperature (80°C). The voltage gradient and solid: liquid ratio affected the time to reach the target temperature. The highest energy efficiency value for all voltage gradients and solid: liquid ratios were obtained in the 0 min holding time, and the efficiency value, which changed between 89.47% and 56.02%, was negatively affected by the increase in the holding time. The exergy efficiency was lower than the energy efficiency and decreased due to the increasing holding time and decreasing voltage gradient. Also, the exergy efficiency was found to be between 73.69% and 18.09%. Determining the performance characteristics of the system will make a significant contribution to pilot and industrial-scale system/process applications for the future. Practical application: In this study, pectin was successfully obtained from grapefruit powder using an ohmic heating system. The operating conditions for the obtained pectin include constant pH (pH:1) and temperature (80°C) but various voltage gradients, solid: liquid ratios, and extraction times. It has been observed that voltage gradient and extraction time were effective on energy efficiency. When looking at exergy efficiency, voltage gradient, solid: liquid ratio, and extraction time were effective. It has been observed that the improvement potential (IP) value calculated for the system decreases depending on the increasing voltage gradient. The results obtained in this study are thought to be an important data source for literature, pilot, and industrial-scale production systems. It has been realized that ohmic heating, which is increasingly used, is an alternative technique for pectin production.
AtıfScopus13WoS12OpenAlex16İncele - MakaleAçık Erişim2022Scopus SJRQ2Investigation of the Effects of Deformation Aging Applied to AA 7075 Aluminum Alloy on Mechanical and Metallographic Properties
Taşgın, Yahya; Ergin, Ramazan
Aging is quite important in improving the mechanical properties of aluminum alloys. One of the most widely used Al alloys is AA7075 aluminum alloy. Since AA7075 aluminum alloys contain aluminum-zinc-magnesium-copper, various aging processes have been applied to improve their mechanical qualities, and as a result, they have become commercially available. When this aluminum alloy series with increased strength is subjected to any thermal effect in industrial use, the loss of mechanical properties can be reduced by applying deformation aging. In this study, the effect of deformation aging on the mechanical properties of commercially available aluminum alloy has been determined and the relationship between mechanical properties and microstructure examined. Deformation aging was applied to 7075 Al alloy in our study by cooling in air, water and oil at temperatures of 120–180 °C for 2–24 hours. Structural differences were revealed by examining the effects of heat treatment on the mechanical properties and machinability properties of the alloy. As a result of the study, it was observed that metallographic precipitation occurred in the AA7075 Al alloy, and accordingly, intermetallic phases were formed. It is thought that various nanoscale fine precipitates occurring in the matrix of this alloy can also prevent dislocation movements. The study has positive effects on the mechanical properties of the material.
AtıfScopus9WoS6OpenAlex8İncele - MakaleAçık Erişim2022Scopus SJRQ3SOME PHYTOCHEMICAL CONTENTS AND ANTIOXIDANT ACTIVITIES OF TWO PRANGOS LINDL. (UMBELLIFERA) SPECIES GROWN IN TURKEY
Hayta, Şükrü; Aydin, Sevinç; Topdemir, Aykut
The genus Prangos is a member of the Apiaceae family, and it has been a focus of the attention of researchers due to its high nutritional value and some special medical properties. In this study, the total phenolic and flavonoid contents and antioxidant activities of the leaf and fruit extracts of the Prangos ferulacea and Prangos uloptera species belonging to this genus were studied, and the properties of these two species were compared to each other. In the study, the Folin-Ciocalteu method was used for the analysis of the total phenolic content, methanolic formaldehyde was used for the total flavonoid content, and both analyses were carried out with a UV-VIS spectrophotometer device. The antioxidant activity of the specimens was measured based on the Trolox equivalent antioxidant capacity (TEAC) method. It was found that the P. ferulacea species had higher total phenolic and flavonoid content values than the P. uloptera species. The P. ferulacea species was also more effective in terms of antioxidant activity, which is known to be associated with these properties. When the fruit and leaf extracts of each species were compared, it was found that the total phenolic and flavonoid content of the fruit extract of the P. uloptera species was higher than that of its leaf extract, and the antioxidant activity of the fruit extract was also higher in proportion to these values. In the P. ferulacea species, as opposed to the case of P. uloptera, all values except for the total flavonoid values were higher in the leaf extract than the fruit extract.
- MakaleYalnız künye2022Scopus SJRQ1Cooling of non-sloped, positively sloped, and negatively sloped arrangements of Li-ion batteries with a phase change material connected to a solar system
Akkurt, Nevzat; Aghakhani, S.; Mahmoud, Mustafa Z.; Abdelrahman, Anas
Three cylindrical Li-ion batteries are simulated using COMSOL Multiphysics in this study. A circular PCM layer is used to cover the batteries. A battery pack connected to a solar system is tested to store energy in a residential building. The PCM is 100% melted at the beginning, and the frozen PCM volume fraction (PVOF) is studied over time. In addition, the temperatures of individual batteries in three different configurations are analyzed at air velocities 1 and 3 mm/s. The three battery configurations included a positive slope, a negative slope, and no slope. The finite element method (FEM) is utilized to derive algebraic equations. The test results are given to the network as training data, and different neural network architectures are tested in terms of the number of layers and the number of neurons in each layer, and finally a structure that has a minimum mean squared error as a network. Battery behavior predictor is selected. Finally, this model is given to the optimization algorithm as an optimization function to investigate the point at which the maximum voltage is obtained. The results showed that the positively sloped battery configuration decreased the temperatures of the batteries, while the non-sloped configuration increased the temperatures. In addition, the positively sloped configuration resulted in more frozen PCM than non-sloped and negatively sloped configurations at a given time. The minimum frozen PCM was observed in the non-sloped configuration. A change in the air velocity from 1 to 3 mm/s increased the frozen PCM and improved the cooling of the batteries.
AtıfScopus15OpenAlex13İncele - MakaleYayıncıda açık erişim2022Scopus SJRQ1Self healing of alkali active mortars with expanded perlite aggregate
Yılmazer Polat, Berivan
The use of alkali-activated mortars instead of cemented mortars provides an advantage in terms of various properties such as high strength, fast curing, and high durability by terminating cement production. However, concrete cracks reduce durability and strength, thus, it is crucial that they be healed. This study aimed to investigate the healing of early microcracks in geopolymer mortars by using Sporasarcina pasteurii, which makes carbonate precipitation, and expanded perlite aggregate as the bacteria carrier. This is the first study to investigate the bacterial healing of an alkali-activated geopolymer mortar using expanded perlite aggregate without applying a complex encapsulation process to the bacterial agents. For this purpose, optical, physical, and mechanical changes caused by self-healing were observed ahead of and after the cure period with tests like water absorption, compressive strength, UPV, SEM, FTIR, and optical microscope images. The results showed that bacterial cells could sporulate directly on the expanded perlite aggregate, visually improving the crack closure rate of the samples by a majority to 100 %, and the unit weights of all samples healed in DM and containing bacteria increased by up to 5 %.
AtıfScopus33WoS31OpenAlex28İncele - MakaleAçık Erişim2022The impact of reflective practices on pre-service science teachers’ classroom teaching practices
Kılıç, Aygün
This case study attempts to explore the impact of the reflective practices (reflection in, on, and for action) on pre-service science teachers’ (PSTs’) classroom teaching practices. To this end, ten PSTs majoring in Science Teacher Education Program participated in this study. In the study, the author designed a classroom teaching practice process based on reflective practices. This process was carried out during the teaching practicum course with the pre-service teachers participating in the research. At the beginning and end of the study, classroom observations, field notes, classroom observation instruments, teaching video records, and lesson plans were used as data collection tools in determining PSTs' classroom teaching practices. The qualitative and quantitative results of this study indicated that there was a significant change in favor of post-classroom practice results between PSTs' pre-and post-classroom teaching practices. Given these results, the classroom practice process based on the reflective practices carried out in the research plays an important role in the development of PSTs' classroom teaching practices.
AtıfScopus20OpenAlex24İncele - MakaleAçık Erişim2022Scopus SJRQ1Experimental study on heat transfer properties of gravity heat pipes in single/hybrid nanofluids and inclination angles
Wang, Zhaoxiao; Zhang, Hui; Yin, Lei; Yang, Di; Yang, Gang; Akkurt, Nevzat; Liu, Dinghai; Zhu, Lidong; Qiang, Yujie; Yu, Fan
In order to meet the working requirements of heat pipes under complex working conditions and high heat flux density, and propose corresponding thermal management solutions. In this paper, the single and hybrid nanofluids (TiO2-H2O, Al2O3-H2O, Al2O3+TiO2-H2O) with mass fraction of 5% under the gradient of gravity heat pipe at 50°, 60°, 70°, 80°, 90° are studied. The changes in thermal resistance, thermal efficiency and equivalent heat transfer coefficient of water were compared with deionized water. The results are as follows: The overall efficiency of gravity heat pipe ranges from 70% to 85%. Compared with deionized water, the nanofluid can effectively improve the heat transfer. At different inclination angles, the hybrid nanofluid with the same mass fraction shows the reverse trend compared with the single nanofluid by decreasing the thermal resistance of the heat pipe and increasing the heat transfer efficiency. At an inclination angle of 70°, the heat transfer efficiency of the nanofluid Al2O3+TiO2-H2O is 6.8% weaker compared to TiO2-H2O and 4.5% weaker compared to Al2O3-H2O. At a tilt angle of 60°, the heat transfer capacity of Al2O3+TiO2-H2O nanofluid increases by 7.3% compared to TiO2-H2O and by 5.6% compared to Al2O3-H2O.
AtıfScopus47OpenAlex45İncele - MakaleAçık Erişim2022Scopus SJRQ1Development of generalized Fourier and Fick’s law of electro-osmotic MHD flow of sodium alginate based Casson nanofluid through inclined microchannel: exact solution and entropy generation
Khan, Dolat; Asogwa, Kanayo Kenneth; Akkurt, Nevzat; Kumam, Poom; Watthayu, Wiboonsak; Sitthithakerngkiet, Kanokwan
Electro-osmotic flow via a microchannel has numerous uses in the contemporary world, including in the biochemical and pharmaceutical industries. This research explores the electroosmotic flow of Casson-type nanofluid with Sodium Alginate nanoparticles through a vertically tilted microchannel. In addition, the transverse magnetic field is also considered. In this flowing fluid, the influence of heat and mass transmission is also explored. The aforementioned physical process is represented by partial differential equations. Utilizing suitable dimensionless variables for nondimensionalized. Furthermore, the non—dimensional classical system is fractionalized with the use of generalized Fourier and Fick's law. Generalizations are made using the Caputo derivative's description. The analytical solution of the velocity, temperature, and concentration profiles is obtained by combining the methods of Laplace and Fourier. Interestingly, the influence of several physical characteristics such as the fractional parameter, Casson fluid parameter, the thermal and mass Grashof numbers, and the zeta potential parameter is displayed. Moreover, the results show that the volume fractional of nanoparticles enhances the rate of heat transfer up to 39.90%, Skin friction up to 38.05%, and Sherwood number up to 11.11%. Also, the angle of inclination enhances the fluid velocity.
AtıfScopus25OpenAlex29İncele - MakaleAçık Erişim2022Scopus SJRQ3The Effects of Probiotic-Prebiotic on the Biomass and Protein Content of Spirulina platensis in Different Temperatures and Illuminations
Seyhaneyıldız Can, Şafak; Seyhaneyıldız, Elif; Dörücü, Mustafa
The blue-green algae Spirulina platensis Geitler 1925 has been used by people since ancient times due to its high protein content. This study was conducted to determine the effect of a Probiotic-Prebiotic (P-P) product, which contains Bifidobacterium infantis, Bifidobacterium thermophilum, Leuconostoc mesenteroides as probiotic bacteria, and beta-glucan and oligosaccharide as a prebiotic mixture on S. platensis. In the study, four groups were one of which was a control. In this study, we investigated whether the P-P product contributed to the biomass development and protein production of S. platensis under different temperatures and lighting conditions. In terms of biomass, the P-P product gave different responses at different temperatures and light intensities, but its results were positive in all groups in terms of protein ratio. The most positive effect on biomass and protein content was in the group where 0.1 ml/L P-P product was added, at 40°C and 3200 lux with 68.71% protein content and an average OD of 0.727.
AtıfScopus5WoS5OpenAlex5İncele - MakaleAçık Erişim2022Scopus SJRQ1DEEP LEARNING BASED A COMPREHENSIVE ANALYSIS FOR WASTE PREDICTION
Utku, Anıl; Kaya, Sema Kayapinar
In its simplest definition, waste can be defined as any substance that is used, not needed and causes harm to the environment. Waste management covers control activities such as prevention of the formation of waste, reuse, separation according to its characteristics and type, storage, transportation, recycling and disposal. The main purpose of waste management is to leave a livable world to future generations, to create a sustainable environment, to protect natural resources, to save energy and costs, to reduce the rate of pollution and the amount of hazardous waste. In today's world where urbanization and industrialization rates are increasing, waste management is gaining importance. The aim of this study is to utilize waste data from Istanbul, Turkey's largest and fastest growing city, to estimate waste amount using a constructed Long Short-Term Memory (LSTM) based deep learning model. The developed LSTM-based model has been compared in practice with k-Nearest Neighbors (kNN), random forest (RF), Support Vector Machine (SVM), multi-layered perceptron (MLP) and Gated Recurrent Unit (GRU). As a result of the comparative and comprehensive analyzes, the experimental results showed that the developed LSTM-based deep learning method is more successful in the waste prediction problem than the other compared models.
AtıfScopus13OpenAlex13İncele - MakaleYalnız künye2022Scopus SJRQ2Characterization of the mechanical and thermal properties of rape short natural-fiber reinforced thermoplastic composites
Kısmet, Yılmaz; Dogan, Akar
In this study, the effects of filler amounts were studied on the mechanical and thermal properties of high-density polyethylene (HDPE), polystyrene (PS) and polyoxymethylene (POM) polymers reinforced with short rape fibers. HDPE-rape, POM-rape and PS-rape fiber composite materials were prepared with different fiber contents and their tensile, flexural, Izod impact and TGA/DTA properties were examined. When tensile and Izod impact properties were compared, it was observed that an increase in the amount of filling in HDPE-based composites did not cause any significant changes in these peoperties, while they were decreased for POM- and PS-based composites. On the contrary to tensile and impact strengths, when the three-point flexural properties were examined, it was observed that the strength values of all these materials increased with increasing the amount of fillers. However, a pronounced increase was observed in the three-point flexural strength of the HDPE-based composite materials. The flexural strength of 30 wt% rape-reinforced HDPE composite was found to be twice that of the pure HDPE. The results of TGA and DTA analyses revealed that the reinforcement element started to burn before the matrix material and therefore burning was delayed in these thermoplastics. As a result, the mechanical properties of HDPE composite materials improved with rape reinforcement. In this way, by using approximately 30 wt% natural filling material in a polymeric matrix, an environmentally friendly material, as well as, significant advantages in cost can be obtained. Graphic abstract: [Figure not available: see fulltext.].
AtıfScopus25WoS25OpenAlex33İncele - MakaleAçık Erişim2022Scopus SJRQ3GEOMETRY OF KENMOTSU MANIFOLDS ADMITTING Z-TENSOR
Barman, Ajit; Ünal, İnan
The object of this paper is to study Kenmotsu manifolds admitting Z−tensor, which is a generalization of Einstein tensor that comes from general rel-ativity. We define a special type of quarter-symmetric non-metric ϕ and η-connection on a Kenmotsu manifold and we examine some geometric properties of such manifolds with Z−tensor. Some semi-symmetry conditions related to Z−tensor are studied on Kenmotsu manifolds and finally, we ob-serve our results on a 5-dimensional Kenmotsu manifold.
AtıfScopus6İncele - MakaleAçık Erişim2022Scopus SJRQ1Experimental and Numerical Analysis of Forced Convection in a Horizontal Tube Partially Filled with a Porous Medium under Local Thermal Equilibrium Conditions
Amoli, Behzad Siavash; Ajarostaghi, Seyed Soheil Mousavi; Saffar-Avval, Majid; Abardeh, Reza Hosseini; Akkurt, Nevzat
The objective of the present work is to analyze experimentally and numerically the laminar forced convection flow in a horizontal pipe partially filled with a porous medium under constant heat flux and to study the influence of the eccentricity of the porous medium on the results. In a numerical analysis, the governing equations are solved in three dimensions. To simplify the grid generation and the satisfaction of the boundary conditions, conformal mapping is applied to convert the cross-section of the tube in the fluid domain (space between two eccentric circles) into a rectangle, and the equations are solved in a computational domain in this domain. The Darcy–Brinkman–Forchheimer model is applied to simulate the hydrodynamic behavior of the flow in the porous region. Thermal equilibrium between solid and fluid is assumed for the energy equation. A FORTRAN program was developed to solve the equations using the finite volume method and the SIMPLE algorithm. Velocity profile, pressure drop and average Nusselt number are studied in a wide range of Darcy numbers, thickness of porous mediums and eccentricities. The results show that the eccentricity of the porous material reduces the heat transfer coefficient and the pressure drop simultaneously; of course, the reduction in the heat transfer coefficient is less noticeable when the thickness of the porous medium is smaller. For example, at RP = 0.5, when the eccentricity of the porous medium increases up to E = 0.4, the average Nusselt number decreases by 66%, and this reduction for a smaller porous thickness decreases to 11%. The maximum pressure drop reduction for Da = 10−5 and E = 0.4 is 25%.
AtıfScopus11WoS8OpenAlex9İncele - MakaleYalnız künye2022Scopus SJRQ2The effects of different packaging methods and sous vide cooking on chemical, sensory, and microbiological changes of marinated crayfish (Astacus leptodactylus Esch., 1823)
Kurt Kaya, Gülderen
Chemical and sensory parameters and the microbiological condition of marinated crayfish (Astacus leptodactylus), with emphasis on the quality and safety parameters, in brine, vacuum packaging (VP), and sous-vide cooking were investigated. Quality assessment of crayfish stored in in brine, vacuum packaging (VP), and sous-vide (SV) for up to 120 days at 4 ± 1°C was done by the monitoring of sensory parameters, microbiological condition, pH value, total volatile basic nitrogen (TVB-N), thiobarbituric acid (TBA), and peroxide value (PV). The highest concentration of TVB-N was recorded in the marinated crayfish stored under brine whereas the lowest TVB-N in the marinated crayfish stored under SV packed conditions. The concentration of TBA increased and its level reached over 5.44 mg MA/kg for crayfish stored in brine, 3.57 mg MA/kg for VP and 2.54 mg MA/kg for SV at 120 days. The formation of PV increased with the time of storage and was the lowest in the marinated crayfish stored in SV packed. During storage period, aerobic and anaerobic colony count, Escherichia coli, Coagulase positive staphylococcus, Listeria monocytogenes, Salmonella, and Clostridium perfringens were not found in any of samples. The marinated crayfish packed in sous-vide had extended shelf life at 4 ± 1°C compared to that packaged in brine and VP according to physicochemical analysis. Novelty impact statement: The biochemical quality degradation was considerably inhibited in SV-processed samples. Sous-vide packaging style had antioxidant activity. Crayfish processed by sous vide extended shelf-life to 120 days.
AtıfScopus5WoS5OpenAlex4İncele - MakaleYalnız künye2022Scopus SJRQ2Boron nitride nanosheet-reinforced WNiCoFeCr high-entropy alloys: the role of B4C on the structural, physical, mechanical, and radiological shielding properties
Kavaz, Esra; Gul, Ali Oktay; Basgoz, Oykum; Guler, Omer; ALMisned, Ghada; Bahceci, Ersin; Guler, Seval Hale; Tekin, H.O.
The synthesis and extensive characterization of newly developed boron nitride nanosheet (BNNSs)-reinforced WNiCoFeCr high-entropy alloys (HEAs) are presented. The influence of B4C on the structural, physical, mechanical, and nuclear shielding characteristics of synthesized HEAs has been widely examined in terms of its monotonic effects on the behavior changes. The internal morphology and structural characteristics of the fabricated composites are first investigated using X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. Wear testing is used to determine the coefficient of friction as a function of sliding distance. Experimental gamma ray and neutron setups are created to determine their shielding characteristics against nuclear radiation. Finally, the shielding characteristics of nuclear radiation for gamma ray and fast neutrons are compared extensively to those of many existing and new-generation shielding materials. Among the examined samples, the S2 sample with B4C and BNNSs reinforcement had the greatest mechanical characteristics. Our findings imply that increasing B4C directly contributes to the shielding qualities of nuclear radiation. The B4C created in the structure of BNNSs contributes to the overall properties of HEAs, which are crucial for nuclear applications, since HEAs are being examined as a component of future nuclear reactors. Additionally, B4C is a very versatile material that may be used in circumstances where mechanical and nuclear shielding properties need to be enhanced for a variety of radiation energies.
AtıfScopus11OpenAlex12İncele
