Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Dertli, Enes(116)
- Şahin, Engin(48)
- Kaya, Yunus(46)
- Özen, Soner(46)
- İspirli, Hümeyra(45)
- Pat, Suat(44)
- Şenay, Volkan(42)
- Korkmaz, Şadan(36)
- Yilmaz, Mustafa Tahsin(33)
- Kutlu, Naciye(32)
- Cuce, Erdem(31)
- Öner, Erdal(31)
- Artar, Musa(30)
- Ertugrul, Mehmet(29)
- Hasar, Ugur Cem(29)
- Mercan, Emin(28)
- Bayraktar, Bülent(27)
- Bayram, Sinan(27)
- Can, Zehra(25)
- Ecem Bayram, Nesrin(25)
- Çolak, Murat(23)
- Özdemir, Akın(23)
- Cuce, Pinar Mert(22)
- Sert, Durmuş(22)
- Ayata, Ümit(21)
- Bayram, Ozkan(21)
- Dirican, Ebubekir(20)
- Abdioglu, Murat(19)
- Ayazoglu, Rabil(19)
- Birinci, Ahmet(19)
- Kamiloğlu, Aybike(19)
- Gerçek, Yusuf Can(18)
- Taylan, Osman(18)
- Tozlu, Alperen(18)
- Gul, Volkan(15)
- Hasar, Ugur C.(15)
- Kadakal, Mahir(15)
- Sagdic, Osman(15)
- Ergün, Mustafa(14)
- Kadakal, Huriye(14)
Yayınlar
- MakaleYalnız künye2022Scopus SJRQ1Powder flow behaviour, functional characteristics and microstructure of whole milk powder produced from cow and buffalo milk mixtures
Sert, Durmuş; Mercan, Emin; Kılınç, Mehmet
The effects of cow and buffalo milk mixtures on powder flow behaviour, functional characteristics and microstructure of whole milk powder was investigated. Milk powder was produced from 100% cow milk (G1), 100% buffalo milk (G2), 75% cow/25% buffalo milk (G3), 50% cow/50% buffalo milk (G4) and 25% cow/75% buffalo milk (G5). A higher proportion of buffalo milk increased the hydroxymethylfurfural, thiobarbituric acid reactive substances and free fatty acid contents in powders, but decreased dispersibility and wettability. The lowest and highest mean particle size values were obtained in G3 and G2 samples. Milk powder containing a higher level of buffalo milk increased caking ability and compaction coefficients of milk powder. All samples had remarkably cohesive characteristics. A higher proportion of cow milk can improve the flow behaviour of milk powder containing cow and buffalo milk mixtures in terms of caking, cohesion, and powder speed flow dependency.
AtıfScopus11WoS7OpenAlex8
İncele - MakaleYalnız künye2022Scopus SJRQ3Optimization of Ultrasound Extraction of Phenolic Compounds from Tarragon (Artemisia dracunculus L.) Using Box–Behnken Design
Kutlu, Naciye; Kamiloglu, Aybike; Elbir, Tugba
In this study, ultrasound extraction of bioactive compounds from tarragon was examined as a sustainable technology. Pure water, which is a green solvent, was used as solvent. Box–Behnken was used in the experimental design, and ultrasonic power, extraction time and solvent-to-sample ratio were determined to be independent variables. The physicochemical properties were determined by physical (color, pH, Brix) and chemical analyses (antioxidant activity, total flavonoid and total phenolic compound (TPC)) in the extracts obtained under different conditions. Optimum conditions were found to be 73.9% ultrasonic power, 43.2 min sonication time and 10 mL/g solvent-to-sample ratio. The composite desirability (R2) of optimum conditions was 99.3% after optimization. Since high efficiency was obtained in a short time with ultrasound extraction, it was found to be quite good in terms of energy savings. That is, the highest TPC was obtained with a sonication time of 45 min with this method, while similar TPC in the control group (maceration) was obtained in 24 h. In the optimum conditions, extraction with other green solvents (ethanol and deep eutectic solvent—DES) was carried out and bioactive compound yields were compared. For different solvents compared under optimum conditions, ethanol gave higher yields in terms of TPC, while higher yields were obtained in samples using water as solvent for some antioxidant activity values. The results obtained with DES were not as high as expected, and this resulted in the conclusion that a hydrogen bond donor is not suitable for obtaining bioactive compounds from tarragon.
AtıfScopus9WoS9OpenAlex9İncele - MakaleAçık Erişim2022Scopus SJRQ1Optimum sizing design of steel frame structures through maximum energy dissipation of friction dampers under seismic excitations
Artar, Musa; Carbas, Serdar
This paper focuses on optimum sizing design of steel frame structures equipped with friction dampers (FDs) in order to prevent the vulnerable effect of an earthquake. The fundamental concept is to maximize the energy dissipation of implemented FDs under different seismic excitations. The FDs utilized as passive energy dissipation devices in a steel structure increase the energy dissipation capacity of the structure by decreasing the seismic demand during an earthquake. In this context, the Pall friction dampers (PFDs) are implemented as diagonal damped brace members in investigated structures. Three different earthquake records (Kobe, Kocaeli-Duzce, Erzincan) are utilized to acquire nonlinear dynamic responses of the steel frame structures through time-history analyses. The open application programming interface (OAPI) functions are used to integrate a finite element modelling based structural analysis program, SAP2000, with a design optimization algorithm encoded in MATLAB for achieving the exact structural behaviours by synchronously data transferring. As an optimizer, one of the recent nature-inspired metaheuristic techniques, so-called Grey Wolf (GW) algorithm is used. Initially, under effect of seismic excitations, the steel frame structures are optimally sized for attaining minimum design weights without implementing the PFD elements by subjecting only strength, displacement, drift, and geometric structural design constraints taken from AISC-LRFD practice code provisions. Afterward, in order for optimally modelling the PFD elements, the frames are equipped with PFDs to calculate optimum yield strengths that is defined as slip load of a PFD. To do so, the GW algorithm ensures the maximizing of the dissipated energy and controls the yield strengths between the stories since the shear force due to the earthquake increases towards the base of the structure. Eventually, the provisions-based sizing design optimizations of the steel frame structures equipped with optimally modelled PFD elements are conducted under seismic excitations for conclusive evaluations.
AtıfScopus21WoS18OpenAlex20İncele - MakaleYayıncıda açık erişim2022Scopus SJRQ2Evaluation of photon interaction parameters of Anti-HIV drugs
Akbaba, Uğur; Şakar, Erdem; Abu Al-Sayyed, Mohammed Ibrahim; Alim, Bünyamin; Özpolat, Özgür Fırat
Medical treatment inevitably exposes individuals to radiation, including those taking drugs used to treat and prevent human immunodeficiency virus (HIV). Motivated by this, we investigated the radiation interaction properties of several HIV drugs to determine the interaction parameters, mass attenuation coefficient (MAC), atomic cross section (ACS), electronic cross section (ECS), effective atomic numbers (Zeff), and effective electron density (Neff). We calculated the values using the Phy-X/PSD software in the range of 0.015–15 MeV. Additionally, we calculated the exposure build-up factor (EBF), and energy absorption build-up factor (EABF) values of the drugs up to 40 mean free path (MFP) using the geometric progression (G-P) method. From our findings, we determined that Combivir, with its relatively high heavy element content, had the highest radiation attenuation capacity, whereas the probability of Lopinavir interacting with photons was the lowest compared with the other drugs. The results of the EBF and EABF parameters, including the scattering effects, ordered the drugs opposite to the primary interaction parameters such as MAC, ACS, ECS, and Zeff. These findings can guide the treatment process of HIV-positive patients and inform HIV prevention practices conducted alongside radiotherapy, as the interaction between radiation and a drug may cause deterioration in the drug's structure.
AtıfScopus9WoS8OpenAlex12İncele - MakaleAçık Erişim2022Scopus SJRQ1Charity Social Media Marketing and Its Influence on Charity Brand Image, Brand Trust, and Donation Intention
Bilgin, Yusuf; Kethüda, Önder
This study aims to identify the outline of charity social media marketing (SMM) and to determine to what extent it influences the charity brand image, brand trust, and donation intention. The data were gathered from followers of internationally operating Turk charities on social media. The theoretical model and hypotheses were tested by using structural equation modeling. Charity SMM is composed of awareness, interaction, timeliness, informativeness, customization, and advertisement dimensions. Awareness is the only dimension of SMM that has a significant direct influence on donation intention. Timeliness, informativeness, and advertisement significantly influence charity brand image, whereas brand trust is influenced by informativeness and customization. Besides, Charity SMM, as a whole, influences donation intention both directly and indirectly through brand image and brand trust. Therefore, charity brand image and brand trust are crucial for charities to promote donation intention through SMM. Therefore, charities are strongly recommended to focus primarily on developing their brand image and gaining trust in current and prospective donors.
AtıfScopus63WoS49OpenAlex69İncele - MakaleYalnız künye2022Scopus SJRQ3Gram-scale synthesis of (S)-1-(thiophen-2-yl)ethanol in high enantiomeric purity under Enterococcus faecium BY48 biocatalysts
Şahin, Engin
Sulfur-containing chiral heterocyclic secondary alcohols are relevant intermediates in the preparation of enantiomerically pure compounds endowed with biological activity. In this report, we evaluated the reductive potential of different lactic acid bacteria as whole-cell biocatalysts of the enantioselective reduction of 1-(thiophen-2-yl)ethanone (1). Enterococcus faecium BY48, isolated from boza, a cereal-based fermented beverage, was found to be the best biocatalyst in our initial investigations. Using whole-cell preparations of E. faecium BY48, we then systematically analyzed the reaction parameters (pH, incubation period, agitation speed, and temperature) to optimize the yield, the enantiomeric excess (e. e.), and the conversion leading to (S)-1-(thiophen-2-yl)ethanol [(S)-2]. The target derivative, which is a precursor in the synthesis of biologically active chiral compounds, was obtained in enantiomerically pure form, gram-scale amounts, and high yield. This is also the first report that the manufacture of (S)-2 in excellent conversion, yield, enantiopure form, and gram scale used whole-cell biocatalyst. This whole-cell E. faecium BY48 biocatalyzed reaction is a clean, environmentally friendly, and cost-effective process, representing a valuable alternative to chemical catalysis or previously reported biocatalytic procedures in the preparation of (S)-2.
AtıfScopus3WoS3OpenAlex5
İncele - MakaleYalnız künye2022Scopus SJRQ2Applications of innovative polygonal trend analyses to precipitation series of Eastern Black Sea Basin, Turkey
Hırca, Tuğçe; Eryılmaz Türkkan, Gökçen; Niazkar, Majid
Examining historical variations of hydroclimatic variables can provide crucial information about changes of water resources in a water cycle. In this study, the Mann–Kendall (MK) and Innovative Polygon Trend Analysis (IPTA) methods were applied to 56-year precipitation data collected at 8 measuring stations. These stations are located in Eastern Black Sea Basin (EBSB), which has a significant amount of annual precipitation and hydroelectric potential in Turkey. This study has two objectives: (1) investigating possible changes in the monthly precipitation and (2) comparing the results achieved by a classical (MK) and one of the latest trend analysis methods presented in the literature (IPTA). Based on the results, MK achieved no trend for most of months, while it reached an increasing trend for March at most of the stations. Likewise, IPTA determined an increasing trend for March precipitation. However, an increasing/decreasing trend was obtained by IPTA for most of the months and stations. In other words, comparing the trend analysis results obtained by IPTA and MK indicates a significant discrepancy between the numbers of months with detected trends primarily because the former is relatively more sensitive in trend identification. To be more precise, IPTA and MK determined trends in approximately 81.25% and 12.5% of all months, respectively. Furthermore, the former identified quite the same trends in every month which the latter reported a trend. Moreover, the polygon of the mean and standard deviation graphs developed by IPTA provides a year cycle, which brings about useful information for water utility sectors and decision makers of the study area. Finally, the findings of this study contribute to a large amount of research that attempts to explore spatio-temporal variations of hydroclimatic variables around the globe not only to enhance humans’ knowledge about changes in a water cycle but also assess climate change impacts.
AtıfScopus54WoS50OpenAlex64İncele - MakaleAçık Erişim2022Scopus SJRQ3Functional and technological characterization of lactic acid bacteria isolated from Turkish dry-fermented sausage (sucuk)
Kamiloğlu, Aybike
In this study, 10 lactic acid bacteria were isolated from Turkish fermented sausage (sucuk) and identified as 5 Lactobacillusplantarum, 1 Pediococcus acidilactici, 1 Weissella hellenica, 1 Lactobacillus pentosus, and 2 Lactobacillus sakei. PCR screening of genes encoding plantaricin A and pediocin showed the presence of plantaricin A gene in 9 and pediocin gene in 3 of strains. All isolates showed antibacterial and antifungal effect on most of the tested microorganisms. gad gene, encoding glutamic acid decarboxylase enzyme, was detected in all isolates except Weisella hellenica KS-24. Eight of isolates were determined as gamma-amino butyric acid (GABA) producer in the presence of 53 mM mono sodium glutamate (MSG) by HPLC and TLC analysis. DPPH scavenging activity was observed for all isolates. Additionally, isolates were able to produce exopolysaccharide in the presence of sucrose. The best exopolysaccharide (EPS) production was achieved with L.plantarum KS-11 and L.pentosus KS-27. As a result, this study characterized some techno-functional properties of LAB isolates from sucuk. It was concluded that the isolates studied have the potential to be used in obtaining functional products in meat industry, as well as strain selection may be effective in providing the desired properties in the product.
AtıfScopus23WoS21İncele - MakaleAçık Erişim2022Scopus SJRQ3An Investigation of the Effect of Curing Temperature on the Deformation Characteristics of the Stabilized Soil Layers Treated with Lime and Tuff Wastes with Response Surface Method
Kamiloglu, Hakan Alper; Turan, Huseyin
The shallow spread foundations are one of the widely used foundation types for low-rise, low-cost or commercial buildings. However, it is not possible to use this type of foundation for soils with low bearing capacity or capable of excessive settlements. In these cases, stabilized soil layers overlying insufficient soil may be alternative to the high-cost foundation systems. As the temperature of the soils depends mostly on air temperature for shallow depths, curing conditions of the stabilized soil layers are affected by the air temperature. The effect of curing temperature on the pressure-settlement relation of the layered soil is a gap in the literature. This study investigates the effect of Bayburt tuff on pressure-settlement characteristics of layered soil for various curing temperatures. The specific objectives of this paper are to (1) examine the effect of using the waste tuffs as a stabilization agent in layered soils, (2) evaluate the usability of response surface methodology (RSM) to estimate shear strength parameters (c, ϕ), unconfined compression strength, and secant modulus of the stabilized soil with less experiment, (3) investigate the effect of dimensions of the stabilized soil block (length, with and thickness) on pressure-settlement relations under various curing temperature (T = 3 °C, 13 °C, 23 °C, 33 °C, 43 °C). This study comprises experimental and numerical parts. In the experimental part, strength parameters (c, ϕ) and secant modulus of stabilized soil samples were estimated with response surface methodology for various curing temperatures (3 °C, 23 °C, 43 °C). The effects of curing temperature on shear strength and Bulk’s modulus parameters were determined with the derived RSM model. In the numerical part of the study plate load test was simulated with the derived 2D axisymmetric FE model. The parameters required for the FE analyses were determined with the derived RSM model. As a result of the study, it was seen that it is possible to estimate experimental parameters accurately using the RSM approach with fewer tests. Bayburt tuff and lime mixtures increase the stiffness of the layered soil. The curing temperature has considerable effects on the pressure-settlement relationship up to a certain value. After a certain value increasing curing temperature has no considerable effects on the stiffness of the layered soil.
AtıfScopus3WoS1İncele - MakaleAçık Erişim2022Scopus SJRQ2Pollen morphology of some Veronica species (Plantaginaceae) from Turkey
Varlik, Kader; Armagan, Metin; Bülbül, Ali Savaş
The aim of the present work is to provide an account on the morphological features of pollen of Veronica species in Turkey, as a contribution to future research. Pollen morphology of 20 species of the Veronica were investigated using Light Microscope (LM) and Scanning Electron Microscope (SEM). Different palyno-morphological features including; pollen ornamentation, colpus ornamentation, size of polar and equatorial diameter, P/E ratio, exine thickness, and size of colpus were observed. The study revealed that the pollen grains of the studied Veronica species were in all cases tricolpate, radially symmetrical and isopolar, oblate-spheroidal or prolate spheroidal. The surface pattern of the exine varied from striato-reticulate and striatomicroreticulate to microechinate-perforate, which allows recognition of three homonymous types of pollen grains.
AtıfScopus1WoS1OpenAlex1İncele - MakaleYalnız künye2022Scopus SJRQ2MODELLING AND VALIDATION OF EFFECT OF BINDER TYPE ON FEEDING BEHAVIOUR OF SPHEROIDAL GRAPHITE CAST IRON
Çolak, Murat; Şekerden, Mete
In the casting method, it is crucial to properly make the moulding design to produce sound parts. Volumetric change, especially during the solidification of spheroidal graphite cast irons, may show different behaviour compared to steel and aluminium castings. In this study, castings were carried out with single and double feeders with varying casting parameters of green sand and resin mould sand containing different cross-sectional thicknesses. Depending on the chemical composition, mould rigidity and inoculation efficiency, and the importance of the feeder path was evaluated by experimental and modelling techniques. Consequently, it was observed that the risk of shrinkage in resin moulds is less than in green sand castings in the same moulding design. In addition, it has been found that the number of feeders and neck connection is an important parameter in pore formation.
AtıfScopus2OpenAlex3İncele - MakaleAçık Erişim2022Scopus SJRQ2Optimization of ohmic heating-assisted osmotic dehydration as a pretreatment for microwave drying of quince
Kutlu, Naciye
In this study, the ohmic heating system was used as a novel application for osmotic dehydration of quince. After osmotic dehydration, samples were dried by microwave. In this regard, the effects of process variables such as electrical field strengths (20, 30 and 40 V/cm), holding time (10, 20 and 30 minutes), microwave power (90, 180 and 270 W) and sucrose concentration (0%, 25% and 50%) on dielectric constant, dielectric loss factor, rehydration ratios, total phenolic compounds and color values were investigated by response surface methodology (RSM). Optimum conditions were found as 40 V/cm electrical field strength, 30 min holding time, 16.67% sucrose concentration and 270 W microwave power. Total phenolic content, rehydration ratio, color differences and dielectric properties of the novel method were found to be higher than that of control. Moreover, Midilli and Wang & Sing models gave the superior fit to the moisture ratio data obtained during drying.
AtıfScopus44WoS36OpenAlex38İncele - MakaleAçık Erişim2022Scopus SJRQ2Applicability of Phenolic Profile Analysis Method Developed with RP-HPLC-PDA to some Bee Product
Kara, Yakup; Can, Zehra; Kolaylı, Sevgi
In this work, a reverse phase high-performance liquid chromatographic method (RP-HPLC) with photo diode array (PDA) at 4 different wavelengths (250, 280, 320 and 360) for the determination of some polyphenols in some bee products (honey, pollen, and propolis) is developed. The analyses were carried out on C18 column (250 mm x 4.6 mm, 5 μm; GL Sciences), and the gradient program was used with a mobile phase A reservoir with 70% acetonitrile and the B reservoir with 2% acetic acid. The HPLC method was founded that limit of detection was in the range 0.022-0.0908 μg/mL; the limit of quantification was in the range 0.074-0.3027 μg/mL, all calibration curves were linear R2>0.995 within the range, the recovery range was 91.43-111.37% for 10 ppm and 98.44-101.68% for 40 ppm and relative error levels 0.0330-0.0290 respectively. The developed method was applied to some bee products available on the Turkey market. The study aimed at phenolic profiles of the bee products extracts were revealed by using 25 phenolic standards. The proposed method was optimized, quickly, and simple validated by evaluating the linear range, the limits of detection and quantification, the accuracy, the precious, the repeatability, and recoveries suitable for the phenolic analysis. It is concluded that evaluated and the quantitative determination of the bee products can be made quickly and reliably with the optimized method.
AtıfScopus35WoS35OpenAlex41İncele - MakaleAçık Erişim2022Scopus SJRQ2Non-family Employees in Family firms and Turnover Intentions: The Relevance of Identification and Justice Perceptions
Yazici, Omer; Memili, Esra; Patel, Pankaj
Many family firms hire and rely on non-family employees; therefore, the mutual benefits provided to both family and non-family members are important. Yet, the perspectives of non-family employees have been under researched. Drawing upon organizational identity and justice theories and the extant literature on family influence, this study examines non-family employees' perceived family influence, family firm identification, family firm justice, and turnover intentions in a sample of 301 family business non-family employees. Path analysis results show that non-family employees' perceived family influence can lead to family firm identification, in turn diminishing their turnover intentions. We also find that non-family employees' perceptions of family firm justice moderate the relationship between non-family employees' perceived family influence and family firm identification. We conclude by discussing implications.
AtıfScopus6WoS7OpenAlex8İncele - Kitap BölümüAçık Erişim2022Scopus SJRQ3Optimum Discrete Design of Steel Planar Trusses Comprising Earthquake Load Impact
Carbas, Serdar; Artar, Musa; Kim, JH; Deep, K; Geem, ZW; Sadollah, A; Yadav, A
In this study, the success of teaching–learning-based optimization (TLBO) and biogeography-based optimization (BBO) metaheuristic methods in optimum discrete sizing design of a steel planar truss comprising earthquake load impact has been investigated. To do this, a 46-element steel planar truss has been handled as a design example. Like many other stochastic optimization methods, the TLBO and BBO techniques imitate specific natural events. In TLBO, the processes are carried out by mimicking a class consisting of teachers and students; on the other hand, the BBO simulates the distribution of species in nature based on biodiversity. The stress and displacement constraints in American Institute of Steel Construction-Allowable Stress Design (AISC-ASD) provisions are considered as structural behavior constraints. Both algorithms select design profiles from a discrete list containing steel W-shaped sections. For obtaining the minimum weighted optimum structural design, the algorithms encoded in MATLAB are supplied with open application programming interface (OAPI) functions that enable mutual data transfer with a structural analysis software (SAP2000) to practically get the structural responses under the effect of load combinations containing earthquake load. The optimal truss designs yielded with TLBO and BBO algorithms are compared with those already existed in the literature. Accordingly, it has been concluded that the TLBO and BBO algorithms give successful solutions.
AtıfScopus3WoS2İncele - MakaleAçık Erişim2022Scopus SJRQ4HRM method for identification of TP53 exon 5 and 8 mutations in human prostate cancer patients
Özmerdiven, Çağdaş Gökhun; Dirican, Ebubekir; Ayan, Semih; Tatar, Zeynep; Çakır, Sami; Güler, Yavuz; Karadağ, Abdullah; Soydaş, Tuğba; Uzunçakmak, Sevgi Karabulut; Aru, Melek
Background: The purpose of the present study was to perform a high-resolution melting (HRM) analysis to discover mutations in gene exons 5–8 of tumor protein p53 (TP53), as well as the relationships of these mutations to clinical parameters in prostate cancer (PC). Methods: Genomic DNA was extracted from 50 formalin-fixed paraffin-embedded (FFPE) tissues with PC. Mutations in exons 5 and 8 of TP53 were analyzed using the HRM method. Sanger sequencing was used to describe mutations. Results: According to the HRM analysis results, 21 (42%) PC samples had different normalized and shifted melting curves from other samples. Mutations in TP53 exons 5 and8 were observed in 12 (24%) patients by the Sanger method. The detection sensitivity of the HRM method in exon 5 and exon 8 mutations was 66.7% and 50%, respectively. PSA levels of PC patients with TP53 mutation were found to be lower than that of patients with no mutation (p = 0.8270). However, we did not find any correlations between TP53 mutations and clinical parameters (p > 0.05). Conclusions: HRM analysis is a simple, rapid, and efficient mutation-scanning method for known/unknown mutations in TP53 exons 5and8, as well as an attractive method for detection of mutations and their analysis in FFPE tissues. Additional studies with larger patient populations are warranted to confirm the correlation between the TP53 mutations and PC risk.
- MakaleAçık Erişim2022Scopus SJRQ3Design of an efficient vehicle-actuated signal control logic for signalized intersections
Cakici, Ziya; Murat, Yetis Sazi; Aydin, Metin Mutlu
The effectiveness of fixed-time management systems dramatically decreases in case of fluctuating traffic demands in signalized intersection approaches. The result is the utter waste of time in traffic to be followed by material, psychological, and ecological problems. In recent years, to minimize the negative impacts of these problems, many researchers have focused on Intelligent Transportation Systems (ITS). As it is known, one of the applications of ITS is called vehicle-actuated (traffic-actuated) management systems. Because the success of these types of applications is directly related to the created control logic, the selection of the most proper control parameters for the created control logic is an important issue. This study aims to create an effective control logic and flow chart for the vehicle-actuated management system. At the end of the analyses, it is seen that the created vehicle-actuated management system can adapt to fluctuations in traffic demands in signalized intersection approaches. Average vehicle delays, fuel consumptions, and exhaust emissions can be reduced significantly by the created system. In case of fluctuations in traffic demands in intersection approaches, it is concluded that the performance of the intersection may increase enormously because of the created vehicle-actuated management system.
AtıfScopus4WoS6OpenAlex7İncele - MakaleAçık Erişim2022Scopus SJRQ3Performance Analysis of Buck-Boost and SEPIC Converter for Commutation Torque Ripple Minimization in BLDC Motors
Çorapsız, Muhammed Reşit; Kahveci, Hakan
This paper discusses comparative analysis of Buck-Boost and SEPIC (Single Ended Primary Inductance) converters used in DC link voltage control technique to reduce torque ripple in Brushless Direct Current Motors (BLDCM). The aim of this study is to prove the efficiency of the aforementioned two converters, which have been adopted in many studies to reduce torque ripples caused by commutation, on the same motor parameters. Although BLDCM has many advantages, ripples in the generated torque have limited the use of these motors in applications requiring precise speed and torque. In this study, BLDCM was analyzed exhaustive mathematically and electrically and the problem that caused commutation torque ripples was explained in detail. The DC link voltage control has been proposed to suppressing torque ripples in the BLDCM. In addition, the link voltages required for reducing the torque ripples were obtained separately via both the Buck-Boost and the SEPIC converters. These converter topologies are examined under certain speed and torque conditions and the results were compared. When the results are evaluated together, it was observed that both converters performed the very closely performance each other. However, the Buck-Boost converter produced the desired voltage levels with less oscillation than the SEPIC converter.
AtıfScopus5WoS2OpenAlex3İncele - MakaleYalnız künye2022Scopus SJRQ3Designing learner control in instructional software: a lens of 'time spent on tasks' to determine the mental effort
Çakiroǧlu, Ünal; Aksoy, Dilara Arzugül; Gencan, Ayşegül; Şen, Hasan
This study aims to determine the relationships between mental effort and the use of learner controls while working with instructional software. Various versions of instructional software including control components were developed to examine this relationship. Twenty-four secondary school students participated in the study and studied with instructional software including different controls in the content pages. All content pages consisted of the content area, image area, and control panel components. Five different page templates including different positions of these components were placed on the pages. Quantitative data were gathered from the cognitive load scale and the time spent on tasks was used for measuring the mental effort spent on the tasks in the software. The results indicated that students who used more controls spent more mental effort. Along with the study findings, the factors affecting the perceptions of cognitive load regarding the time spent on the controls were discussed. Implications were suggested for designers within the cognitive effects of learner control.
- MakaleAçık Erişim2022Scopus SJRQ3Exergy analyses of two and three stage cryogenic cycles
Atasbak, Musa; Keven, Arzu; Karaali, Rabi
Cryogenics has an important influence on industry and science. In this study, optimum working conditions are obtained by applying exergy analysis and local optimization methods to two- and three-stage vapor compression cascade cryogenic cycle. The first and second laws of thermodynamics, exergy analysis, and local optimization methods are applied to the two- and three-stage cascade cryogenic cycle. By considering the needs and demands, it is possible to create new cycles by adding new devices and/or new stages to these cycles. The results of the optimum operating conditions are obtained for the two- and three-stage vapor compression cascade cryogenic cycle. It is seen that to achieve high COP values and high efficiency; it is necessary to reduce the compression ratio of the compressor as much as the fluid allows. For the two-stage cycle, the minimum total work required for cryogenic cooling is around P 7 = 2,400 kPa. The COP value is 0.30 between P 7 = 2,400 and 2,800 kPa, and the maximum exergy efficiency is obtained around 0.235. It is seen operating the first-stage compressor at high pressures increases the total losses of the entire cycle from 7,500 to 18,550 kW. The increase in total exergy losses is around 247%, and operating the first-stage compressor at high pressures increases the exergy efficiency of the entire cycle. The increase in total exergy efficiency is around 160%. When the second-stage compressor is operated at low pressure, the COP value increases by 2%, the exergy efficiency increases by 20%, and the exergy losses decrease by around 40%.
AtıfScopus6WoS3OpenAlex9İncele