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Koleksiyondaki öğeler
- MakaleYalnız künye2020Scopus SJRQ4Innovative flow risk assessment with climate change perspective in Yesilirmak Basin
Serancam, Ugur; Dabanli, Ismail
Surface temperature increase due to global warming results in polar ice melting, snow cover thinning, changes in precipitation anomaly. All these phenological effects alert engineers, planners and administrators to be more sensitive against climate change-based risk effects on water structures. Vulnerability to natural disasters such as floods and droughts are expected to occur more frequent than past. Therefore, design and potential evaluation of water structures such as transmission channels, water wells, dams and hydraulic power generation facilities need to be re-evaluation. This re-evaluations procedure must be updated by taking into consideration climate change impacts with their risk assessments. For this purpose, the climate change-based risk levels are calculated from historically available records through possible trend tendencies, which are expressed in terms of trend slope. It has been observed that, in general, the climate change impacts are not significant on precipitation and runoff. This is due to the low trend slopes in the standardized hydro-meteorological time series. This point has been documented for Yesilirmak basin, where the climate change impact is very limited.
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İncele - MakaleYalnız künye2020Scopus SJRQ1Terrorism - workers’ remittances nexus: empirical evidence from Turkey
Arİ, Yılmaz Onur; Bello, Ibrahim
The paper examines the impacts of remittances on terrorism for Turkish economy by using annual time series data covering the period of 1990-2019. Autoregressive Distributed Lag (ARDL) was used in the application of econometric method. To ensure robustness of results, the study accounts for structural breaks in the unit root test and the co-integration analysis. The results obtained indicated that remittances flows to Turkey have a positive and significant effect on terrorism. This is in line with the empirical evidence that finances through remittances can promote terrorism in a country. The study also concludes that unemployment has strong a correlation in promoting terrorism in Turkish economy and that persistent unemployment can cause economic inequality, poverty, social dislocation, unrest, and conflict such as terrorism, which has a negative impact on subsequent long-run economic growth. Besides, trade openness shows a negative but significant effect, which indicates that trade openness has a little influence in promoting terrorism.
AtıfScopus2İncele - Derleme MakaleAçık Erişim2022Scopus SJRQ1Impact of ultrasonication applications on color profile of foods
Kutlu, Naciye; Pandiselvam, R.; Kamiloglu, Aybike; Saka, Irem; Sruthi, N.U.; Kothakota, Anjineyulu; Socol, Claudia Terezia; Maerescu, Cristina Maria
Food color is a feature that provides preliminary information about their preference or consumption. There are dominant pigments that determine the color of each food; the most important pigments are anthocyanins (red–purple color), chlorophylls (green color), carotenoids (yellow-orange color), and betalains (red color). These pigments can be easily affected by temperature, light, oxygen, or pH, thereby altering their properties. Therefore, while processing, it is necessary to prevent the deterioration of these pigments to the maximum possible extent. Ultrasonication, which is one of the emerging non-thermal methods, has multidimensional applications in the food industry. The present review collates information on various aspects of ultrasonication technology, its mechanism of action, influencing factors, and the competence of different ultrasonication applications (drying, irradiation, extraction, pasteurization, cooking, tempering, etc.) in preserving the color of food. It was concluded that ultrasonication treatments provide low-temperature processing at a short time, which positively influences the color properties. However, selecting optimum ultrasonic processing conditions (frequency, power, time, etc.) is crucial for each food to obtain the best color. The key challenges and limitations of the technique and possible future applications are also covered in the paper, serving as a touchstone for further research in this area.
AtıfScopus135WoS118OpenAlex129
İncele - MakaleAçık Erişim2022Scopus SJRQ2Investigation of inlet air pressure and evaporative cooling of four different cogeneration cycles
Karaali, Rabi
The objective of this study was to search the effects of the inlet air compressor pressure and evaporative cooling of four different cogeneration plants that are absorption cooling (ab), basic (bsc), air heating (airh), and air fuel heating (airfh) cogeneration systems by using the first law and the second law of thermodynamics, and the exergy analysis methods. For analysis, a program is written by the author in the FORTRAN programming language. Decreasing the atmospheric pressure or increasing the installation altitude of the plants increases the Z factor (ratio of lost exergy to useful exergy) of the four cycles about 10-13%. Also, decreasing inlet air pressure decreases the specific work about 25-28%, and the fuel energy saving ratio of the four cycles decreases about 29-30%. The method of water spray cooling of the compressor inlet air especially in the summer months, the humidity increases and the evaporative cooling can be obtained. By using this method, the ratio of lost exergy to useful exergy can be decreased for the four cycles about 0.5-2%. Also, the specific work of the four cycles can be increased about 1.2-6%.
AtıfOpenAlex4İncele - MakaleAçık Erişim2021Scopus SJRQ3Honey: Determination of volatile compounds, antioxidant and antibacterial activities
Karlidag, Semiramis; Keskin, Merve; Bayram, Sinan; Mayda, Nazlı; Ozkok, Aslı
Honey is an important functional food for human health and nutrition that is collected by honey bees and stored in the honeycombs. In this study, total phenolic content, antioxidant activity and volatile compounds of 13 different honey samples collected from various districts of Malatya province were investigated. As a result of this study, it was determined that the total phenolic content varied between 8.50 mg GAE 100 g–1 and 73.90 mg GAE 100 g–1 and it was observed that the honey samples were rich in aldehydes, aliphatic acid and esters, alcohols, hydrocarbons, carboxylic acid esters, ketones, terpenes, fatty acids and esters. In addition, the antibacterial effects of honey samples were determined against 18 different pathogenic bacteria using agar well diffusion (AWD) method, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). In AWD assay, it was recorded that inhibition zone diameters varied between 9 mm and 14 mm and honey samples were found to have a partial inhibitory effect against selected target pathogens.
AtıfScopus5WoS3OpenAlex7İncele - MakaleYalnız künye2020Scopus SJRQ3Some harmonic problems on the tangent bundle with a berger-type deformed sasaki metric
Altunbas, Murat; Simsek, Ramazan; Gezer, Aydin
Let (M2k, ϕ, g) be an almost anti-paraHermitian manifold and (T M, gBS) be its tangent bundle with a Berger type deformed Sasaki metric gBS . In this paper, we deal with the harmonicity of the canonical projection π: T M → M and a vector field ξ which is considered as a map ξ: M → T M.
AtıfScopus9İncele - Kitap BölümüYalnız künye2021Is a New Understanding of Tourism after Covid-19 Possible?
Çelebı Boz, Füsun; Gültekın, Ömer Faruk
- MakaleAçık Erişim2022Scopus SJRQ2Investigations of low-velocity impact behaviour of single-lap joints having dissimilar hybrid composite adherends through cohesive zone model approach
Erbayrak, Engin
The low-velocity impact behavior of single-lap joints was investigated in this study. In single-lap joints, woven carbon fiber reinforced epoxy (CFRE) and plain woven glass fiber reinforced epoxy (GFRE) laminates as well as a hybrid composite laminate (HCGFRE), which is formed by stacking carbon and glass composite laminates, are used as adherends. Araldite 2011 and Araldite 138 M/HV998 epoxy adhesives were used with different mechanical properties for joining similar and dissimilar composite adherends. Low-velocity impact tests were carried out with 40 J impact energy. Reaction force-time and impact energy-time graphs were obtained from the experimental study as impact response. In numerical analyses, the damage approach of composite adherend was modeled using composite stress-based failure model (Mat 59) and adhesives were modeled utilizing a mixed-mode cohesive zone model (Mat 138) that existed in LS-DYNA explicit finite element software. It was seen that the numerical results indicated a similar tendency with the experimental results due to the modeling of the adhesives using the proper cohesive zone model, the application of correct boundary conditions, and the selection of the correct contact type.
AtıfScopus9WoS9OpenAlex10İncele - MakaleAçık Erişim2021Scopus SJRQ3Morgan-Voyce polynomial approach for quaternionic space curves of constant width
Aydin, Tuba Ağirman; Ayazoğlu, Rabil; Kocayiğit, Hüseyin
The curves of constant width are special curves used in engineering, architecture and technology. In the literature, these curves are considered according to different roofs in different spaces and some integral characterizations of these curves are obtained. However, in order to examine the geometric properties of curves of constant width, more than characterization is required. In this study, firstly differential equations characterizing quaternionic space curves of constant width are obtained. Then, the approximate solutions of the differential equations obtained are calculated by the Morgan-Voyce polynomial approach. The geometric properties of this curve type are examined with the help of these solutions.
AtıfScopus1WoS2OpenAlex1İncele - MakaleAçık Erişim2020Scopus SJRQ3Effect of probiotics supplementation on adipokine profile (Visfatin, adiponectin and chemerin), intestinal (citrulline) and thyroid function in japanese quail subjected to heat stress; [Einfluss einer probiotischen futterergänzung auf das adipokin-profil (Visfatin, adiponectin und chemerin), und die darm- (citrullin) und schilddrüsenfunktion japanischer wachteln unter hitzestress]
Bayraktar, B.; Tekce, E.
In this study, we aimed to determine the effect of probiotic supplementation of Lactobacillus reuteri E81 (LRE; 200, 400, 600 mg/kg) to the diets of Japanese quail (Coturnix coturnix japonica) reared under heat stress (HS) on serum adipokine (visfatin, adiponectin and chemerin), intestinal (citrulline) and thyroid hormone levels. On day 7 of the trial, the animals were assigned to 8 groups [Control temperature (CT): control (C, without LRE supplementation), LRE-200, LRE-400 and LRE-600 and HS: control (HSC), SLRE-200, SLRE-400 and SLRE-600], each composed of 56 animals of equal body weight. Each group was divided into 4 subgroups withg 14 animals per compartment. During the experiments, the temperature applied to the CT-groups C, LRE-200, LRE-400 and LRE-600 was 25°C and to the HS-groups HSC, SLRE-200, SLRE-400 and SLRE-600 was 37°C. At the end of the study (days 21 and 42), a dose-dependent decrease in citrulline, chemerin, adiponectin, and thyroid hormones and a dose-dependent increase in the visfatin hormone level (p < 0.01) due to LRE supplementation were observed in the HS and CT groups compared to its control. In conclusion, the present study showed that dietary supplementation with 600 mg/kg of LRE affected serum chemerin, adiponectin, T3, T4, TSH and visfatin levels in Japanese quail raised under heat stress (p < 0.001).
AtıfScopus6WoS5OpenAlex2İncele - MakaleAçık Erişim2021Scopus SJRQ1Simple and accurate electromagnetic characterization of omega-class bianisotropic metamaterials using the state transition matrix method
Hasar, Ugur C.; Ozturk, Gokhan; Kaya, Yunus; Barroso, Joaquim J.; Ertugrul, Mehmet
We propose a simple and accurate microwave extraction procedure for full electromagnetic characterization of \Omega -class bianisotropic metamaterial (MM) slabs from normal incidence scattering (S-) parameters using TE1, TE2, and TE3 modes. Its closed-form nature (no need for any numerical analysis and optimization toolbox) and less requirement (a total of seven S-parameters) demonstrate the advantage of our method over other methods in the literature. Our approach was validated and its accuracy was verified by S-parameters, through a full electromagnetic simulation program - CST Microwave Studio, of an edge-coupled \Omega -class split-ring-resonator MM slab.
AtıfScopus15WoS13OpenAlex14İncele - MakaleAçık Erişim2021Scopus SJRQ3Does compliance with the preventive health behaviours against COVID-19 mitigate the effects of depression, anxiety and stress? (¿Cumplir con los comportamientos preventivos de salud contra el COVID-19 reduce los efectos de la depresión, la ansiedad y el estrés?)
Aydin, Fatih; Kaya, Feridun
In the present study, the aim was to investigate the associations between compliance with preventive health behaviours, depression, anxiety and stress. 478 adults living in Turkey voluntarily filled out the online survey, which comprised demographic questions, Measure of Compliance with Preventive Health Behaviours against COVID-19, and Depression Anxiety Stress Scales, between 24–31 March 2020: during the initial phase of the COVID-19 pandemic in Turkey. Results revealed that compliance with preventive health behaviours has negative associations with depression, anxiety and stress. Adults’ compliance with the recommended preventive health behaviours accounted for 14% variance in depression, 9% variance in anxiety and 10% variance in stress. The evidence might indicate that compliance with preventive health behaviours may protect people psychologically against the burden created by the novel COVID-19 pandemic.
AtıfScopus6WoS7OpenAlex6İncele - MakaleAçık Erişim2022Scopus SJRQ2EXTRACTIVES IN THERMALLY MODIFIED TROPICAL HARDWOODS
Esteves, Bruno; Ayata, Umit; Cruz-Lopes, Luísa; Brás, Isabel; Ferreira, José; Domingos, Idalina
Chemical composition of wood is known to change during thermal treatments. Two species grown in Turkey, afrormosia (Pericopsis elata) and duka (Tapirira guianensis) were heat treated according to Thermowood® method. Lignin, cellulose, hemicelluloses and extractives in dichloromethane, ethanol and water were determined. Wood extracts were analysed by gas chromatography with mass detection and existing compounds were identified by NIST17 database. Results show that hemicelluloses and cellulose content decreased for both heat-treated woods along the treatment while lignin percentage increased. The analysis of extractives has shown several compounds normally associated to lignin thermal degradation that increased along the treatment. At the same time several compounds associated to carbohydrate thermal degradation were found in all the extracts for both heat-treated woods. These founding have allowed the understanding of the degradation pattern of wood during thermal modification. There was not much difference between afrormosia and duka woods structural compounds behaviour along thermal modification. However, the variation of the amount of extractives along the treatment depended on the species.
AtıfScopus20WoS20OpenAlex16İncele - MakaleAçık Erişim2019Scopus SJRQ2Prediction of critical fraction of solid in low-pressure die casting of aluminum alloys using artificial neural network
Teke, C.; Colak, M.; Kiraz, A.; Ipek, M.
Casting simulation programs are computer programs that digitally model the casting of an alloy in the sand, shell, or permanent mold and, then, the cooling and solidification processes. However, obtaining consistent results out of casting modeling depends on the incorporation of many accurate parameters and boundary conditions. Critical Fraction of Solid (CFS), which is one of the most important of these parameters, is defined as the point where solid dendrites do not allow any flow of the liquid metal in the mushy zone. Since the CFS value varies based on many factors, inconsistent results can be experienced in the modeling applications. In this study, the CFS value obtained during the solidification of various commercial aluminum alloys' casting process, carried out using low-pressure die casting method, is predicted by using Artificial Neural Network (ANN) method based on alloy type, grain refiner and modifier additions, initial mold temperature, and pressure level parameters. In the scope of the study, 162 experiments are conducted. The results obtained from the low-pressure die casting experiments using a special model designed for the study are validated by using SOLIDCast casting simulation. The CFS values are obtained in this validation range of 33% to 61%. These CFS values are used in the development of ANN models. Mean Absolute Error (MAE), Mean Absolute Percentage Error (MAPE), and Mean Square Error (MSE) are used to assess the prediction accuracy of the ANN models. Calculated values of MAE, MAPE, and MSE are 0.0188, 7.06%, and 0.0006, respectively. The results show that the proposed ANN model predicts a CFS value with high accuracy.
AtıfScopus6WoS6OpenAlex4İncele - MakaleAçık Erişim2021Scopus SJRQ2Modeling and solving assembly line worker assignment and balancing problem with sequence-dependent setup times
Yilmaz, Hamid
Assembly lines appear with various differentiations in order to better include the disabled in the labor market and to increase production efficiency. In this way, the optimal workforce assignment problem that emerges heterogeneously is called assembly line worker assignment and balancing problem (ALWABP). This paper addresses the ALWABP where the simple version is enriched by considering sequence-dependent setup times between tasks. A mixed integer linear programming model is presented, and a simulated annealing algorithm is developed such as an NP-hard problem. In order to test the proposed solutions, 640 benchmark problems in the literature were combined and used. The solutions obtained through using the proposed algorithm are compared with the mixed integer programming model on the small-size test problems. Experimental results show that the proposed algorithm is more effective and robust for a large set of benchmark problems.
AtıfScopus14WoS12OpenAlex16İncele - MakaleYalnız künye2019Scopus SJRQ1Effect of electrospun nisin and curcumin loaded nanomats on the microbial quality, hardness and sensory characteristics of rainbow trout fillet
Meral, Raciye; Alav, Aslıhan; Karakas, CananYagmur; Dertli, Enes; Yilmaz, Mustafa Tahsin; Ceylan, Zafer
Nisin and curcumin loaded (NCL) nanomats having 172 nm mean diameter were successfully fabricated. The effect of NCL nanomats in terms of limitation of Total Mesophilic Aerobic (TMAB) and Lactic acid bacteria (LAB) in fish fillets was tested during the analysis period. On the 4th day, while TMAB load of C was 6.61 log CFU g−1, that of the sample coated with NCL nanomats was found to be 3.28 log CFU g−1. TMAB load of control samples reached above 6 log CFU g−1 on the 4th day of cold storage, TMAB load of fish samples coated with nanomats reached the same level up to the 12th day. The shelf life of coated fillets was extended to 12 day. 3–4 logarithmic decrease was obtained in LAB count by NCL nanomats during the analysis period. On the 4th storage day, the hardness value of C sample decreased 21% compared to NCL samples. All sensory attributes of C samples were acceptable by the 4th day of the storage; while sensory attributes of NCL samples were acceptable by the 10th day of storage. The study revealed that nisin and curcumin loaded nanomats could be effectively used to improve the quality of fish fillets.
AtıfScopus92WoS84OpenAlex91İncele - MakaleAçık Erişim2021Scopus SJRQ2Adipokine, gut and thyroid hormone responses to probiotic application in chukar partridges (Alectoris chukar) exposed to heat stress
Bayraktar, Bülent; Tekce, Emre; Kaya, Hacer; Gürbüz, Ahmet Burak; Dirican, Ebubekir; Korkmaz, Serol; Atalay, Banu; Ülker, Ufuk
The aim of this study was to investigate the effect of Lactobacillus reuteri E81 (LRE) probiotic supplementation on heat stress responses in chukar partridges (Alectoris chukar). The birds were divided into two groups, one of which was exposed to heat stress (HS). Within each group, four subgroups, each including 64 birds, were created for the three treatment doses (200, 400 or 600 mg/kg) of LRE and the control. The experiment was started with day-old birds, kept at a temperature of 25 8C or 37 8C. After a 7-day adjustment period, the LRE supplementation lasted for 35 days. The levels of different adipokines, including visfatin (VF), adiponectin (ADP), chemerin (CHEM), as well as the concentration of plasma citrulline (CIT) and the levels of thyroid hormones (T3 and T4) and thyroid-stimulating hormone (TSH) in the blood were measured at 21 and 42 days of age. A significant correlation (P < 0.01) was found between LRE supplementation and the decrease in serum VF, ADP, CIT, T3 and T4 levels in partridges exposed to HS. On the other hand, no significant relationship was found between LRE supplementation and the serum CHEM and TSH levels (P > 0.05). We concluded that the addition of 600 mg/kg LRE is beneficial in preventing intestinal damage and inflammation provoked by HS.
AtıfScopus13WoS14OpenAlex16İncele - MakaleYayıncıda açık erişim2020Scopus SJRQ2Effects of an Essential Oil Mixture Added to Drinking Water for Temperature-Stressed Broilers: Performance, Meat Quality, and Thiobarbituric Acid-Reactive Substances
Tekce, E.; Çınar, K.; Bayraktar, B.; Takma, Ç.; Gül, M.
This study investigated the effects of an essential oil mixture (EOM; Eucalyptus globulus labill, Tymus vulgaris, Cymbopogon nardus, and Syzgium aromaticum) added to drinking water on temperature-stressed broilers. The performance parameters (body weight, average daily weight, feed intake, and feed conversion ratio), meat quality, and thiobarbituric acid-reactive substances (TBARS) were evaluated. In a 42-d study, 400 Ross-308 male chickens (1-d-old) were randomly assigned to 8 different groups (n = 50), each containing 4 subgroups (n = 8) (22°C Control (C), C + 250 mL/1,000 L, C + 500 mL/1,000 L, C + 750 mL/1,000 L), 36°C (stress control (SC), SC + 250 mL/1,000 L, SC + 500 mL/1,000 L, SC + 750 mL/1,000 L). Adding 750 mL/1,000 L at 22°C and 250 mL/1,000 L at 36°C was more beneficial to the fattening performance parameters than those in the control group. EOM reduced liver weight but increased abdominal fat in the SEOM-250 groups but did not affect other organ weights. EOM had no effect on the TBARS or the b* color parameter while it augmented the a* and L* coordinates of meat color.
AtıfScopus29WoS25OpenAlex23İncele - MakaleAçık Erişim2021Scopus SJRQ2An Experimental and Numerical Determination on Low-Velocity Impact Response of Hybrid Composite Laminate
Erbayrak, Engin; Yuncuoglu, Ercument Ugur; Kahraman, Yusuf; Gumus, Beril Eker
In this study, experimental and numerical investigations were carried out in order to determine the mechanical properties and impact response of hybrid composite laminate. The hybrid composite laminate was formed from plain woven carbon fiber reinforced epoxy (CFRE) and plain woven glass fiber reinforced epoxy (GFRE) fiber using VARTM (vacuum-assisted resin transfer molding) process. The mechanical properties of the hybrid composites were determined using tensile test device with a 1 mm/min loading rate at room temperature. In addition, hybrid composites were subjected to low-velocity impact test under different impact energy levels (10, 20, 30, 40 J) for determining the impact response. Moreover, mechanical properties and impact responses of CFRE and GFRE laminates were also determined to compare to those of hybrid composite (HCGFRE). Microstructure analysis was performed to investigate the damage surfaces of the fiber and matrix in the composite material subjected to impact and tensile forces. In numerical analyses, composite damage model (Mat 54) was utilized in LS-DYNA® explicit finite element program to simulate the impact behavior of CFRE, GFRE and HCGFRE laminates. Consequently, the tensile test results showed that hybrid composite laminate behaved more ductile than carbon composite laminate and it exhibited more brittle behavior than glass composite laminate. Also, it was determined that absorbed energy and impact load capacity of HCGFRE composite laminate are between absorbed energy and impact load capacity of CFRE and GFRE composite laminate. It was determined that numerical results indicate a similar tendency with the experimental results.
AtıfScopus12WoS13OpenAlex14İncele - MakaleAçık Erişim2022Scopus SJRQ4Some Physical, Biological, Hardness, and Color Properties of Wood Impregnated with Propolis
Akçay, Çağlar; Ayata, Ümit; Birinci, Emre; Yalçın, Mesut; Kolaylı, Sevgi
Propolis is a bee product collected by honeybees from various tree species in nature. It has antifungal, antibacterial, antioxidant, and anticancerogenic properties. Recently, propolis has been used in wood protection area because it has antifungal properties and is a natural and environmentally friendly material. In this study, some deciduous wood species were treated with methanolic propolis extracts. Propolis solutions were prepared by dissolving propolis in methanol in concentrations of 0.5%, 2.5%, 5%, and 8%. These solutions were forced deep into the Scots pine (Pinus sylvestris L.), fir (Abies nordmanniana), and spruce (Picea orientalis L.) woodblocks under vacuum and pressure. Water uptake and water-repellent efficiencies of the woodblocks were tested at 2-, 4-, and 20-hour immersion periods. Sample blocks were tested against wood-destroying house borer (Hylotrupes bajulus) (Coleoptera, Cerambycidae) larvae for 21 weeks. In addition, color changes of woodblocks treated with propolis were determined. According to results obtained in the study, the highest water-repellent efficiency was 61.4% in propolis-impregnated spruce wood at concentration level of 8% during the 2-hour period. These results show that propolis extracts could be used as hydrophobic material for wood. Larvae mortality rates indicated that 8% concentration level was not adequate to overcome H. bajulus larvae or propolis is not effective against H. bajulus larvae. While L* value decreases with the increase of impregnation rate, a* and b* values increase in all wood types. As the impregnation rate increased, the total color difference also increased.
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