Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Gul, Muhammet(82)
- Akkurt, Nevzat(67)
- Güler, Ömer(66)
- Baskonus, Haci Mehmet(62)
- Bulut, Hasan(60)
- Tekin, H.O.(52)
- ALMisned, Ghada(49)
- Yucesan, Melih(43)
- Yildirim, Numan(42)
- Yildirim, Nuran Cikcikoglu(38)
- Paksoy, Mehmet Yavuz(36)
- Serdar, Osman(36)
- Zengin, Gokhan(36)
- Ince, Muharrem(34)
- Celik, Erkan(33)
- Benzer, Fulya(32)
- Kocabaş, Mehmet(30)
- Sulaiman, Tukur Abdulkadir(30)
- Tanyol, Mehtap(29)
- Yildirim, Ozal(28)
- Aslan, Naim(26)
- Kök, Mediha(26)
- Özkul, İskender(26)
- Ates, Mehmet(25)
- Danabas, Durali(25)
- Kutluyer, Filiz(25)
- Can, Erkan(24)
- Kutlu, Banu(23)
- Onat, Onur(23)
- Demir, Veysel(22)
- Erten, Fusun(22)
- Guler, Omer(22)
- Say, Yakup(22)
- Güler, Seval Hale(21)
- Yaman, Mehmet(21)
- Baykal, Duygu Sen(20)
- Sançar, Taylan(20)
- Susam, Selim Orhun(20)
- Cakilcioglu, Ugur(19)
- Orhan, Cemal(19)
Yayınlar
- MakaleAçık Erişim2022Scopus SJRQ1Evaluation of the mechanical properties and durability of self-compacting alkali-activated mortar made from boron waste and granulated blast furnace slag
Yön, Merve Şahin; Karataş, Mehmet
The production of high-strength alkali-activated mortar and concrete by using waste materials instead of cement in order to reduce the amount of carbon dioxide released to nature in cement production is an important study that attracts the attention of researchers. In this study, self-compacting alkali-activated mortar samples were produced using boron waste (BW) and granulated blast furnace slag (GBFS). Prismatic samples of 40 × 40 × 160 mm and cubes of 50 × 50 × 50 mm were produced, in which 0%, 5%, 10%, 15%, 20%, 25% of BW were used. To achieve self-compacting alkali-activated mortar (SCAAM) slump-flow test method was conducted by per The European Federation of Specialist Construction Chemicals and Concrete Systems (EFNARC) guidelines. The samples prepared using Na2SiO3 (NS)/NaOH (NH) = 3.0 were exposed to oven curing at 60 °C and 100 °C for 3 days. The flexural and compressive strength (CS) values of 3, 28 and 90 days were obtained for the samples whose curing period was completed. According to the mechanical strength results, influence of capillary water absorption, porosity, water absorption and density and freeze-thaw from durability tests were carried out. After experimental tests, Scanning Electron Microscope (SEM) and Energy-dispersive X-ray Spectroscopy (EDS) images were utilized to determine microstructures of the samples. As a result of the study, it was determined that the highest strengths were obtained at the curing temperature of 60 °C. Also, it was seen that mechanical strengths and durability decreased with the increase in the BW ratio in the mixtures.
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İncele - MakaleYalnız künye2022Scopus SJRQ1A novel prediction model for durability properties of concrete modified with steel fiber and Silica Fume by using Hybridized GRELM
Cemalgil, Selim; Gül, Enes; Onat, Onur; Yılmaz Aruntaş, Hüseyin
The service life performance of conventional and modified concrete subjected to harsh climatic condition environment is directly related to durability properties of concrete like abrasion, freezing and thawing cycles. These properties are critical issues that should be predicted before performing experimental test. On this basis, the basic purpose of this paper is to predict the abrasion loss, freezing and thawing properties of concrete modified with silica fume (SF) and steel fiber (SFb) by using mix design and additional properties. From this point of view, a conducted experimental study was selected as a case study. In the control concrete (CC) mixtures, Portland cement, crushed stone aggregate, and superplasticizer (SP) were used in the selected experimental study. SP in concrete mixtures was used in the amounts of 1.0%, 1.5%, and 2.0% by weight of cement, and so modified concrete was produced with and without SFb according to the target strength of C25. Furthermore, SF and SFb were used in different amounts to modify the concrete. The SF was replaced with cement in the amounts of 7.5%, 10.0%, and 15.0%. In total, 16 different mix designs were prepared with different SP and SF ratios. In addition, SFb was added to all mixtures of designed concrete at a constant amount of 65 kg/m3. Additionally, a 16-mix design was prepared with SFb. Cumulatively, 32 different mix designs were prepared for the experimental study. Tests on the fresh, hardened, and life-cycle performance properties of the concrete were conducted. As for the metaheuristic part of this study, on the basis of the available experimental data, life-cycle performance parameters of the concrete modified with SF and SFb are predicted by using single and hybrid generalized extreme learning machine methods. Eight different data sets were generated with gradually extended input data. Two different outputs were considered: abrasion resistance (AL) and freezing/thawing (FT). Particle Swarm Optimization (PSO) and Grey Wolf Optimization (GWO) algorithms were used to produce binary and ternary hybrid methods. Four different models were proposed as listed: single use of Generalized Extreme Learning Machine (GRELM), binary use of GRELM-PSO, and GRELM-GWO. Finally, PSO and GWO were hybridized and integrated into GRELM. Two quality indicators, namely Root Mean Square Error (RMSE) and correlation of determination (R2), were considered to see the performance of the prediction. The results showed that the proposed ternary prediction model composed of GRELM-PSO-GWO provided more accurate results in all sets from 74% to 91% by extending input parameters, even if complicated parameters are inserted in as an input to the data set.
AtıfScopus28WoS22OpenAlex25İncele - MakaleAçık Erişim2022Scopus SJRQ1Preliminary assessment of health risks associated with consumption of grapevines contaminated with mining effluents in Turkey: Persistent trace elements and critical raw materials
Topal, Murat; Arslan Topal, E.Işıl; Öbek, Erdal
In this study, some persistent trace elements and critical raw materials were investigated in grapevines contaminated with Pb–Zn mining effluents. The persistent trace elements under certain conditions remain without any change in form in the environment over long periods. The critical raw materials are the ones that have economic importance and have the risks associated with their supply. The health risks of persistent trace elements and critical raw materials in the leaves of grapevine that are consumed by humans were determined. The highest persistent trace elements concentrations followed the order of root > stem > leaf for Mn, Cu, Cd, Ni, and Cr while root > leaf > stem for Zn and leaf > root > stem for Pb. The maximum critical raw material concentrations for Co and V followed the order of root > stem > leaf. For Sb and La, these were leaf > root > stem and root > stem > leaf, respectively. The maximum critical raw materials concentrations for W was leaf > stem = root. The total maximum carcinogenic value was 0.146 for Cd while the total minimum carcinogenic value was 0.0054 for Pb. In this study, potential carcinogenic risk values in terms of ingestion of contaminated soil (Cr, Cd, and Ni) and dietary take of grapevine leaves (Ni, Cr, Cd, and Pb) are higher than acceptable levels (1 × 10−4 – 1 × 10−6). Maximum cancer risk on human health was determined as dietary intake of grapevine leaves. When hazard quotient for dietary (HQdie), hazard quotient for ingestion (HQing), and hazard quotient for inhalation (HQinh) values of critical raw materials were examined, the maximum values were observed for children. Also, the highest hazard quotient for dermal (HQder) value was determined for men. The hazard index and total hazard index values were >1 for critical raw materials. As a result, values >1 indicated potential non-carcinogenic human health risk associated with the consumption of grapevines contaminated with mining effluents. Actual region-specific exposure estimates for consumption of grapevines, however, were not evaluated. Integr Environ Assess Manag 2022;18:517–527.
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İncele - MakaleYalnız künye2022Scopus SJRQ2Eco-Friendly, Thermal Resistant Cotton Fabric Enhanced with Nano Zinc Borate Powder
İpek, Yeliz
The easy burning of cotton fabrics, which have the widest usage area among natural fibers, is a serious problem. Thus, treatment with an environmental friend flame retardant material is essential for cotton fabrics. Zinc borates are multifunctional fire retardants. They can act as smoke suppressor, flame retardant and spark suppressor. Since they are non-toxic and environmental friend materials, they are ideal flame retardants for fabric treatment. In this study, nano-sized zinc borate (ZnO·3B2O3·7H2O) was synthesized and cotton fabric was treated with zinc borate powder with a novel method. Zinc borates are slightly soluble in water. They were dissolved with aid of ammonia as zinc ammonia borate complexes and were recrystalised on the cotton fabric fibers through the evaporation of ammonia. The burning resistance of treated cotton fabric was investigated. The hardness, hydrophobicity, smoke suppression and burning resistance of untreated and treated cotton fabrics were compared. Since zinc borates have smoke suppression feature, a more slight smoke was observed and a higher rate of carbonization occurred during combustion test of treated cotton fabric compared to the untreated cotton fabric. In addition, the burning rate was reduced from 2.26 cm/s to 1.26 cm/s.
AtıfScopus4WoS3OpenAlex4İncele - MakaleAçık Erişim2022Scopus SJRQ2Effect of Cu, Sn and Sb addition on the structural, thermal and magnetic properties of body-centered cubic structured CoNiMnGaSi high entropy alloy
Şimşek, Telem; Özkul, İskender; Canbay, Canan Aksu; Avar, Barış; Şimşek, Tuncay; Güler, Seval Hale; Özcan, Sadan; Güler, Ömer; Chattopadhyay, Arun K.
In this study structural, morphological, thermal and magnetic properties of equiatomic CoNiMnGaSi (base), CoNiMnGaSiCu, CoNiMnGaSiSn and CoNiMnGaSiSb alloys are discussed. The formation of solid-solution nanocrystalline bcc structure of the alloys was determined by XRD and DTA techniques. SEM–EDS analyses also revealed the homogeneous distribution of the elements. The room temperature magnetic hysteresis loops showed that as-casted alloys reached saturation easily with coercivity less than or equal to 35 Oe. As the Cu and Sn were added to the alloy, the saturation magnetization was decreased from 112 emu/g to 50 emu/g, which was mainly due to the substitution of non-magnetic atoms to the magnetic Co in the base CoNiMnGaSi alloy, whereas the addition of Sb to the base alloy did not have a significant effect on the Ms. The CoNiMnGaSiSb was found to have the highest Curie Temperature of 670 K, which makes the alloy a promising candidate for power industry-related applications.
AtıfScopus3OpenAlex4İncele - MakaleAçık Erişim2022Scopus SJRQ3A New Rail Surface Defects Detection Approach Using 3D Laser Cameras Based on ResNet50
Santur, Yunus; Yilmazer, Merve; Karakose, Mehmet; Akin, Erhan
Rail transportation systems, which are used as one of the most common means of transportation worldwide, should be regularly inspected to prevent accidents that may occur. The rail condition monitoring can be performed in high accuracy and real time using computer vision, deep learning algorithms today. In this study, a new deep learning based approach using 3D laser cameras for rail inspection is presented. In the proposed approach, two 3D laser cameras placed on a real train, seeing the rail line from the left and right surfaces were used. These data consisting of sensitive distance value constitute the input data of the ResNet50 transfer learning model. The training was carried out on Nvidia Cuda supported graphics processing units using ResNet50 Convolutional Neural Network. During the test phase, the operation speed and accuracy rate of the method was measured by repeating the process on real-time rail profiles. The accuracy rate was calculated as 94%. As a result a new approach is presented based on deep learning using 3D laser cameras for rail inspection is presented.
AtıfScopus12WoS8OpenAlex9İncele - MakaleAçık Erişim2022Scopus SJRQ2Temperature-Dependent Density and Magnetohydrodynamic Effects on Mixed Convective Heat Transfer along Magnetized Heated Plate in Thermally Stratified Medium Using Keller Box Simulation
Ullah, Zia; Akkurt, Nevzat; Alrihieli, Haifaa F.; Eldin, Sayed M.; Alqahtani, Aisha M.; Hussanan, Abid; Ashraf, Muhammad; Jabeen, Mah
The heat transmission properties along the non-magnetized geometries have been numerically obtainedby various researchers. These mechanisms are less interesting in engineering and industrial processes because of excessive heating. According to current studies, the surface is magnetized and the fluid is electrically conductive, which helps to lessen excessive surface heating. The main objective of the current analysis is to numerically compute the temperature-dependent density effect on magnetohydrodynamic convective heat-transfer phenomena of electrical-conductive fluid flow along the vertical magnetized and heated plate placed in a thermally stratified medium. For the purpose of numerical analysis, the theoretical process governing heat and magnetic intensity along a vertical magnetic plate is examined. By using suitable and well-known similarity transformations for integration, the non-linear coupled PDEs for the aforementioned electrical-conductive fluid flow mechanism are changed and subsequently converted into non-similar formulation. The Keller Box method is used to numerically integrate the final non-similar equations. The MATLAB software program plots the transformed algebraic equations graphically and quantitatively. The behavior of the physical quantities such asvelocity graph, magnetic field graph, and temperature plot along with their slopes that arerate of skin friction, the rate of heat transfer, and the rate of magnetic intensity for different parameters included in the flow model. The novelty of the current work is to compute the magneto-thermo analysis of electrically conducting flow along the vertical symmetric heated plate. First, we secure the numerical solution for steady part and then these results are used to find skin friction, heat transfer, and magnetic intensity. In the current work, the fluid becomes electrically conducing due to a magnetized surface which insulates heat during the mechanism and reduces the excessive heating. The results are excellent and accurate because they are satisfied by its given boundary conditions. Additionally, the current problems have a big impact on the production of polymer materials, glass fiber, petroleum, plastic films, polymer sheets, heat exchangers, catalytic reactors, and electronic devices.
AtıfScopus20OpenAlex18İncele - MakaleAçık Erişim2022Scopus SJRQ2A New Hybrid Fuzzy Multi-Criteria Decision Methodology for Prioritizing the Antivirus Mask over COVID-19 Pandemic
Kaya, Sema Kayapinar; Pamucar, Dragan; Aycin, Ejder
During the COVID-19 pandemic, masks have become essential items for all people to protect themselves from the virus. Because of considering multiple factors when selecting an antivirus mask, the decision-making process has become more complicated. This paper proposes an integrated approach that uses F-BWM-RAFSI methods for antivirus mask selection process with respect to the COVID-19 pandemic. Finally, sensitivity analysis was demonstrated by evaluating the effects of changing the weight coefficients of the criterion on the ranking results, simulating changes in Heronian operator parameters, and comparing the obtained solution to other MCDM approaches to ensure its robustness.
AtıfScopus21WoS15OpenAlex23İncele - MakaleAçık Erişim2022Scopus SJRQ1A method for generation of substitution box based on random selection
Artuğer, Fırat; Özkaynak, Fatih
Two basic requirements must be met to encrypt data. These requirements are confusion and diffusion properties. In particular, block cipher algorithms are based on a cryptographic component known as substitution-box to provide the need for confusion. Therefore, attack scenarios generally focus on this cryptographic component. There are alternative design approaches for substitution-box design. It is known that each design approach has several advantages and disadvantages. In this study, an alternative method is proposed to address the problems of the substitution-box design approach based on random selection. The success of the proposed method has been tested in three different scenarios. Analysis results for these three scenarios showed that generated substitution-box provides performance increase for nonlinearity criterion from s-box design criteria. Successful results achieved; It points out that improvement cryptographic components can be used in a variety of practical applications such as block ciphers, masks to prevent side-channel attacks, random number generators, and image encryption algorithms.
AtıfScopus29WoS25OpenAlex35İncele - MakaleAçık Erişim2022Job Satisfaction, Intent to Stay at Work, and Burnout Levels of Nurses Working in Coronavirus Disease 2019 Clinics: A Cross-Sectional Study
Erkuş Küçükkelepçe, Gülhan; Arslan Şeker, Sevda; Karaca, Türkan
Objective: It is thought that the fact that coronavirus disease 2019 pandemic process has been continuing for a long time, and the level of job satisfaction of nurses may have an impact on their intention to experience burnout and stay at work. This study aimed to determine the relationship between job satisfaction, intention to stay, and burnout levels of nurses working in coronavirus disease 2019 clinics. Methods: This descriptive and correlational study was conducted with 325 nurses who were working in coronavirus disease 2019 clinics. Data were collected using the sociodemographic characteristics form, the Minnesota Satisfaction Questionnaire, the Maslach Burnout Inventory, and the Intent to Leave Job Scale. Descriptive statistics, correlation analysis, and regression analysis were used in the analysis of the research data. Results: Emotional exhaustion, depersonalization, personal achievement, and intent to leave explain 45% of job satisfaction (F = 67.911, p =.000); job satisfaction and intent to leave explain 40% of emotional exhaustion (F = 111.470, p =.000), 16% of depersonalization (F = 33.785, p =.000), and 20% of personal achievement (F = 43.102, p =.000); job satisfaction, emotional exhaustion, depersonalization, and personal achievement explain 24% of intent to leave (F = 27.190, p =.000). Conclusion: The prolongation of the coronavirus disease 2019 pandemic, the uncertainty of the process, and the conditions related to the working environment of the nurses have an effect on job satisfaction, burnout, and intent to leave. The continuity of the well-being of employees is an important issue that needs to be emphasized and evaluated, as it will have a multi-faceted effect to be ready for different pandemics in the near/far future.
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İncele - MakaleAçık Erişim2022Scopus SJRQ1Academicians’ awareness, attitude, and use of open access during the COVID-19 pandemic
Turgut, Yigit Emrah; Aslan, Alper; Denizalp, Nuran Varlı
The aim of this research is to reveal academics’ awareness, attitude, and use of open access. In line with the research purpose, the survey research design is adopted. This research consists 151 academics from 12 basic research areas; eight of them being Professor Dr, 17 being Associate Professor Dr, 49 being Doctor Lecturer, and 77 being Research Assistant or Lecturer. A questionnaire consisting of 19 open access and five demographic information questions was used for the data collection tool. The research results show that 75% of the academics have open access awareness and that their awareness is generally created by information that they obtain through the Internet and their friends. In addition, most of the academics indicate that their awareness of open access has increased during the pandemic period. When considering the level of academics’ use of open access, it is found that 75% of the academics use articles in open access journals for their own research and 51% of the academics do not publish any articles in open access journals.
AtıfScopus20WoS18OpenAlex19İncele - MakaleYalnız künye2022Scopus SJRQ2Integrated electron beam irradiation treatment with hydrogen peroxide aqueous solution to inactivate Salmonella on grape tomatoes
Omac, Basri; Moreira, Rosana G.; Castell-Perez, Elena M.
This study investigated the efficacy of integrated electron beam (e-beam) irradiation and hydrogen peroxide (H2O2) aqueous solution treatments to inactivate mixed strains of Salmonella inoculated in grape tomatoes. Whole grape tomatoes were inoculated with a mixed bacterial cocktail composed of five strains of Salmonella enterica corresponding to serotypes Rissen (SAL1449), Montevideo (SAL4599), Saintpaul (476398), and Typhimurium (ATCC 13311 and ATCC 700720), dried in a biological safety cabinet for 2 h at room temperature and then stored at 4°C for 24 h to facilitate bacterial attachment before treatment. Tomatoes in H2O2 (60 mg/L) aqueous solution were irradiated at 0.45, 0.60, 0.75, 1.0, and 1.25 kGy dose. The combined treatment of 1.0 kGy radiation dose and 60 mg/L H2O2 achieved 4-log reductions in Salmonella. The D10−average value of Salmonella in the present study was 0.25 ± 0.01 kGy. Regarding the effect of the treatment on tomato quality, the combined application of e-beam up to 1.25 kGy and H2O2 (60 mg/L) did not affect (p >.05) the color and texture of grape tomatoes compared to non-irradiated samples. Furthermore, the combined treatments of e-beam and H2O2 aqueous solution reduced the dose uniformity ratio (DUR) by 7%, a relevant finding regarding commercial applications of electron beam accelerators. Exposure of the tomatoes to e-beam and water wash with added H2O2 is a promising decontamination system for use in tomatoes and other produce processing. Further studies on the optimization of this integrated treatment are needed. Practical Applications: Electron beam irradiation of tomatoes immersed in hydrogen peroxide (H2O2) solution reduces the dose required to eliminate pathogens in the fresh produce. The integrated treatment ensures minimal changes to produce quality and increased treatment efficiency in terms of dose uniformity.
AtıfScopus5WoS5OpenAlex4İncele - MakaleAçık Erişim2022Scopus SJRQ3Investigation of rutting, fatigue and cracking resistance parameters of CR modified warm asphalt binders compare with SBS modified binders
Akpolat, Mustafa
This study compares the rutting and cracking resistance and fatigue parameters of crumb rubber (CR) modified warm asphalt binders, which were determined by viscoelastic continuum damage (VECD) theory. The effect of the combination of CR modification and Sasobit, a warm mix additive, was investigated. Performance of CR + Sasobit compound was compared with styrene-butadiene-styrene (SBS) modification. Newly developed rheological tests such as multi stress creep recovery (MSCR), lineer amplitude sweep (LAS) and conventional tests were applied to modified binders. It was determined that the CR + Sasobit modified binders improved the rutting parameter better in comparison to SBS-added binders. Although the CR additive improved the rheological properties of the binder at low and medium temperatures, this effect was reduced when used with Sasobit additive. Sasobit additive increased the stiffness and decreased the fatigue parameter at low temperatures. Besides, the results of the LAS test revealed that at high strain values (i.e.> 6%), the fatigue life of CR and Sasobit modified binders was lower than the fatigue life of the pure binder. In other words, CR and Sasobit modified binders could not preserve material integrity.
AtıfScopus13WoS13OpenAlex12İncele - MakaleAçık Erişim2022Scopus SJRQ1A Bayesian BWM and VIKOR-based model for assessing hospital preparedness in the face of disasters
Saner, Halit Serdar; Yucesan, Melih; Gul, Muhammet
Hospitals are the first point of contact for people in the face of disasters that interfere with the daily functioning of life and endanger health and social life. All preparations should be made considering the worst possible conditions and the provided service should continue without interruption. In this study, a multi-criteria decision-making model was developed to evaluate disaster preparedness of hospitals. This decision model includes Bayesian best–worst method (BBWM), the VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) and technique for order preference by similarity to ideal solution (TOPSIS) methods. With the proposed decision model, six main criteria and 34 sub-criteria related to disaster preparedness of hospitals were considered. The criteria and sub-criteria evaluated in pairwise comparison manner by the experts were weighted with BBWM. These weight values and the data obtained from the six Turkish hospitals were combined to provide inputs for VIKOR and TOPSIS. In addition, a comparative study and sensitivity analysis were carried out using weight vectors obtained by different tools. BBWM application results show that the “Personnel” criterion was determined as the most important criterion with an importance value of 26%. This criterion is followed by “Equipment” with 25%, “Transportation” with 14%, “Hospital building” and “Communication” with 12%, and “Flexibility” with 11%. Hospital-2 was determined as the most prepared hospital for disasters as a result of VIKOR application. The VIKOR Q value of this hospital was obtained as 0.000. According to the results of the comparative study, Hospital-2 was determined as the most disaster-ready hospital in all six different scenarios. This hospital is followed by Hospital-4 (Q = 0.5661) and Hospital-5 (Q = 0.7464). The remaining rankings were Hospital-6, Hospital-3 and Hospital-1. The solidity of the results was checked with TOPSIS. Based on TOPSIS application results, Hospital-2 was again found the most-ready hospital. The usage of BBWM in this study enabled the expert group’s views to be combined without loss of information and to determine the criteria and sub-criteria weights with less pairwise comparisons in a probabilistic perspective. Via the “Credal ranking”, which is the contribution of BBWM to the literature, the interpretation of the hierarchy between each criterion has been performed more precisely.
AtıfScopus48WoS37OpenAlex51İncele - MakaleYalnız künye2022Scopus SJRQ2Interval basic uncertain information and related aggregations in decision making
Jin, Lesheng; Mesiar, Radko; Yager, Ronald; Kaya, Sema Kayapinar
The recently proposed basic uncertain information can directly present numerical uncertainties for given real values, but it cannot handle given interval values which themselves also have uncertainties. Against this background, this work proposes the concept of interval basic uncertain information which serves as a generalization of basic uncertain information and involves two types of uncertainties. We analyze some basic operations, weighted arithmetic mean and preference transformation for interval basic uncertain information. The Rule-based decisions and the comprehensive certainty of interval basic uncertain information are also discussed. An illustrative example of multi-source multi-criteria evaluation under interval basic uncertain information environment is presented.
AtıfScopus18OpenAlex17İncele - MakaleYalnız künye2022Scopus SJRQ2Structural characterization and oxidative stability of black cumin oil oleogels prepared with natural waxes
Orhan, Necla Ozdemir; Eroglu, Zeynep
In this study, black cumin oil (BCO) oleogel was produced using natural waxes (beeswax: BW, sunflower wax: SFW, and carnauba wax: CW) to offer a healthy alternative to shortening. Oiling-off was observed only in the BW oleogel (3.88 ± 0.02%). The CW oleogel had the lowest Ea (354.82 kJ/mol), indicating greater resistance to thermal degradation. The highest G′ and G″ were observed in the CW oleogel, while the lowest was observed in the BW oleogel. All oleogel samples displayed weak gel properties (tan δ > 0.1), but the lowest tan δ value belonged to the CW oleogel (0.12). After 4 weeks of storage, the peroxide values of the oleogels were lower than those of bulk oil (p <.05). Finally, the oxidation results showed that the BCO structuring by the waxes effectively protected it from oxidation over eight weeks of storage. Novelty impact statement: The most important innovation of the present study was to investigate the effect of BCO oleogelation on the stability of thymoquinone, the main phenolic compound of BCO. The BCO oleogels had higher thymoquinone content during the first half of the storage period compared with bulk BCO, showing that the oleogel network provides a protective effect against oxidation and thermal degradation.
AtıfScopus14WoS11OpenAlex17İncele - MakaleYalnız künye2022Scopus SJRQ2Thermal analysis of a radiative nanofluid over a stretching/shrinking cylinder with viscous dissipation
Alqahtani, Aisha M.; Riaz Khan, M.; Akkurt, Nevzat; Puneeth, V.; Alhowaity, Awatif; Hamam, Haneen
This study explores the impact of thermal radiation and viscous dissipation on the stagnation point flow of a copper–water nanofluid across a convective stretching/shrinking cylinder. The copper suspension in the base fluid water enables the fluid to conduct more heat by increasing its thermal conductivity. The mathematical model that governs the flow of Cu-H2O nanofluid is formulated by the system of partial differential equations (PDEs) which are then subjected to transformation by introducing suitable similarity variables so the system is transformed to the Ordinary Differential Equations (ODEs). These equations have been solved numerically via the bvp4c package in MATLAB. The outcomes have been signified graphically in the form of heat transfer rate, temperature, skin friction and velocity which are dependent on the concerning flow parameters. For each of these result, dual solutions have been produced which are conditional on the shrinking of cylinder. These results declare that the skin friction increases for the shrinking cylinder and decreases for the stretching cylinder whereas an opposite trend is seen for the rate of heat transfer. Similarly, heat transfer is found to be decreasing for the increase in both Biot and Eckert number. Meanwhile, the existence of greater values of curvature parameter causes to enhance both first and second solution of velocity as well as the temperature is augmenting with the increase in Eckert number and volume fraction of nano particles.
AtıfScopus38OpenAlex39İncele - MakaleAçık Erişim2022Scopus SJRQ3Economic analysis of rare earth element processing methods for Mountain Pass ore
Uysal, T.
The increasing demand for rare earth elements (REE) in highly strategic sectors such as hybrid electric vehicles, renewable energy, communication technologies, and the defense industry has made REE production methods important. In recent years, studies on REE have increased rapidly; however there are many studies on REE, there are not enough studies in the literature on the economics of the beneficiation process. RE ores are generally leached after beneficiation by gravity, magnetic and flotation methods. In this study, direct leaching, attrition scrubbing and leaching, and flotation and leaching methods are evaluated economically based on the data for the Mountain Pass (MP) facility. According to the sensitivity analysis performed as a function of capital cost (CAPEX), operating cost (OPEX), and rare earths oxides (REO) recovery, REO recovery has the biggest effect on the process economies. Although the flotation method entails additional investment and operating costs, transportation and operating costs are significantly reduced result of the higher grade and recovery. The flotation method is more profitable, with larger NPV and IRR values and a shorter payback period.
AtıfScopus8WoS8OpenAlex10İncele - MakaleAçık Erişim2022Scopus SJRQ2Effects of silver/selenium/chitosan doped hydroxyapatite coatings on REX-734 alloy: Morphology, antibacterial activity, and cell viability
Aksakal, B.; Say, Y.; Sinirlioglu, Z.A.
The goal of this study was to improve the antibacterial activity and cell viability of the Rex-734 alloy in biomedical applications. Various biocomposite coatings, such as single-layer hydroxyapatite (HAp), HAp/silver(Ag), and HAp/selenium(Se)/chitosan(Chit), were applied to Rex-734 alloy at various film thicknesses. The surface coatings were characterized by scanning electron microscopy, SEM, EDX, XRD and coating thickness and hardness of surface coatings were measured. The in vitro antibacterial activities of the coated and uncoated substrates were tested against Esherichia coli JM 103 and Staphylococcus aureus ATCC29293. In vitro cell–material interactions using Saos-2 osteoblast cells were characterized by the 3-(4,5-dimethylthiazol2-yl)− 2,5-diphenyltetrazolium bromide (MTT) assay for cell viability. The post-coating sintering parameters were shown to have a significant effect on the surface morphology. When compared to single HAp and HAp/Ag coatings, Se and Chit additions to HAp powders revealed good crack-free coating surfaces. Crack-free coating morphologies were achieved with a sintering speed of 3 °C/min. While single-HA coatings had an antimicrobial efficiency of 83% against E. coli, this value increased to 94% with Ag additive and to 85% with Se additive. Similarly, Ag and Se additives improved HAp's antimicrobial efficiency against Staphylococcus aureus. Cell viability decreased in the HAp/Ag coating at 86.5% and 90.93%, but increased significantly (p < 0.05) in the HA/Se-Chit coating at 137,43% and 158.23% at the end of the first and seventh days of incubation, respectively. The addition of Ag/Se/Chit to HAp increased the viability of the Rex-734 cells. Furthermore, it was revealed that the HAp-doped Se/Chit duplex biocomposite coating groups increased bone cell viability at much higher rates than the single-layer HAp coatings.
AtıfScopus12WoS8OpenAlex8İncele - MakaleAçık Erişim2022Scopus SJRQ1A multicriteria approach to integrating occupational safety & health performance and industry systems productivity in the context of aging workforce: A case study
Ortiz-Barrios, Miguel; Silvera-Natera, Esnela; Petrillo, Antonella; Gul, Muhammet; Yucesan, Melih
Aging represents one of the greatest challenges that mankind will have to face in the 21st century. In this regard, there is a need to deepen the technical and organizational aspects for rebalancing the job/employee relationship. Nevertheless, there are no robust approaches assisting decision-makers in the effective management of Occupational Safety & Health Performance (OSHP) and Industry Systems Productivity (ISP) convergence with a focus on Aging Workforce (AW). There is no single and unique solution. Therefore, in a win-to-win logic that favors the characteristic of the reference scenario, the aim of this paper is to propose a multicriteria approach to integrate OSHP and ISP in the context of AW. More specifically, Intuitionistic Fuzzy Analytic Hieararchy Process (IF-AHP) was used to elicit the criteria and sub-criteria under uncertainty considering degree of belongingness and non-belongingness. Decision Making Trial and Evaluation Laboratory (DEMATEL) was applied to evaluate the presence and strength of the interrelations and feedback among OSHP and ISP criteria and sub-criteria. Finally, Combined Compromise Solution (CoCoSo) was implemented to calculate a Working Suitability Index (WSI) per aging. Based on this index, interventions on each worker are proposed to underpin redesign of the company while to provide a flexible management propelling high performance in terms of OSHP and ISP. A real case study in Colombia is presented. The results revealed that Efficiency and Quality with 0.162 were found to be the most important factors in evaluating the performance of aging electrical engineers while Psychosocial risk and Occupational Safety were concluded to be the main drivers for a joint OSHP-ISP aging workforce management. The model can be an useful tool for policy and business decision-makers from the electrical sector and can be replicated with slight changes in other industries.
AtıfScopus17WoS11OpenAlex23İncele