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Koleksiyondaki öğeler
- MakaleAçık Erişim2021Fuzzy inverse logic: part-2. validation and evaluation of the method; [Bulanık ters mantık: kısım-2. yöntemin doğrulanması ve değerlendirilmesi]
Öztekin, Ertekin
In the first part of this study, which consists of two parts, the introduction of the fuzzy inverse logic method, its foundations, computation and process flow and details were given. In this second part, the method was applied on a very simple mathematical problem and on a simple civil engineering design problem in order to investigate and evaluate the validity of the method easily. Fuzzy inverse logic computations have been carried out on these two simple problems for different dimension, sensitivity and acceptable error values. By comparing the obtained results with the desired outputs and mathematical results, the effective computation ability of the method was tried to be revealed. As a result, it is understood that the method developed in this study has many promising aspects in terms of theoretical computations and practical applications and can be used effectively in many scientific fields.
AtıfScopus2OpenAlex3TR Dizin1
İncele - MakaleYalnız künye2022Scopus SJRQ2Assessment of excavability classification in a Limestone Quarry: A case study from Bayburt, Turkey
Külekçi, Gökhan; Vural, Alaaddin; Aliyazicioğlu, Şener
Excavability is a measure of material which can be excavated with classical excavation equipment. Studies to decide the rock excavability characteristics contribute to the suitability of engineering projects. In this study, a limestone quarry (in Bayburt, Turkey) was analysed with excavability classification systems and appropriate systems were determined. To accomplish this aim, point load index and Schmidt hardness tests were practiced and changed to uniaxial compressive strength tests. After that, findings were categorized with classification systems in excavation and matched against practices from field. In this study, rock mass was addressed as “pre-explosion”, “hard ripping” and “hammer and blasting” in accordance with distinctive classification systems. All determined as rock mass should be blasted for loosening then dug with hydraulic breakers. This practice is totally compatible with in-site excavations fulfilled. According to study results, the most suitable parameters to decide surface excavational classification are load strength index, geological strength index and the degree of rock mass weathering
AtıfScopus3WoS2
İncele - MakaleAçık Erişim2020Scopus SJRQ2A simple design method for multiple tuned mass dampers in reduction of excessive vibrations of high-speed railway bridges; [Yüksek hızlı demiryolu köprülerinde aşırı titreşimlerin azaltılmasında paralel bağlı ayarlı kütle sönümleyiciler için basit bir tasarım yöntemi]
Kahya, Volkan; Araz, Onur
In this study, a simple method is proposed to obtain the optimum design parameters of vibration absorbers consisting of several tuned mass damper units connected each other in parallel. The method is essentially the extension of the formulas proposed by Den Hartog for single degree-of-freedom tuned mass dampers to multiple tuned mass dampers. To demonstrate the effectiveness of the proposed method, an application to high-speed rail bridges are made. The bridge is modeled as a simple Euler-Bernoulli beam, and the train is modeled as a series of moving loads. The equations of motion are solved numerically by the Newmark method. The results of the study showed that multiple tuned mass dampers designed by the proposed method show good performance in reducing the resonance vibrations in high-speed rail bridges.
AtıfScopus18WoS19OpenAlex5TR Dizin4İncele - MakaleYalnız künye2021Scopus SJRQ1Particle Erosion Performance of Additive Manufactured 316L Stainless Steel Materials
Azakli, Zeki; Gümrük, Recep
Many critical parts such as surface parts of high-speed trains, bins and hoppers, and pipes, bends and valves in material transportation applications as well as a helicopter, mixer, and turbine blades, which can be exposed to particle wear due to the application environment, can be easily manufactured today due to the advances in 3D printing technology. For this reason, an experimental study was carried out to determine the particle erosion behavior of 316L stainless steel parts built by the laser melting method, which is one of the 3D printing technologies. The rectangular plate samples produced with various laser manufacturing parameters were subjected to particle erosion tests at different impingement angles in accordance with the ASTM G76 standard at 140 m/s impact speed. The results showed that the erosion behavior develops in a characteristic similar to the wrought sample, and laser parameters play an efficient role. For example, the porosity ratio decreases at low scanning speeds, resulting in significant improvements in erosion behavior. Also, it was found that the particle erosion behavior of the 3D printed parts could be improved in a serious amount by applying a heat treatment process. Consequently, the obtained results in this study promotes the more comprehensive works regarding the optimization of several laser manufacturing parameters such as scan speed, build direction, laser power, hatch spacing, layer thickness, scan strategy and laser exposure time to obtain the best particle erosion behavior and determination of the most suitable materials among the several others which can be used in 3D printing.
AtıfScopus19WoS17OpenAlex17İncele - MakaleYalnız künye2020AN OVERVIEW TO THE DYNAMIC BEHAVIOUR OF THE INVERTED T TYPE CANTILEVER RETAINING WALL TAKING INTO ACCOUNT SOIL STRUCTURE INTERACTION PHENOMENON
Cakir, Tufan; Ozturk, Kasif Furkan
The dynamic response of the cantilever retaining walls is affected by many factors such as the geometry of the wall, the earthquake frequency content, the wall flexibility, the backfill characteristics, and the soil structure interaction. Therefore, it may not be possible to analyse all aspects of the dynamic response of the cantilever retaining walls in spite of their simplicity. It is also well known that some unfavourable effects on the behaviour of the walls may impair the balance of the wall. In this context, the study aims to investigate the dynamic response of the T type cantilever retaining wall considering soil structure interaction. In line with this purpose, the soil structure interaction system is produced with a three dimensional finite element model. The seismic analyses are performed in time domain using C-OLC360 component of 1983 Coalinga earthquake, and four different foundation soil systems are used in these analyses. The elasto-plastic behaviour of the backfill and the foundation soil are represented with Drucker-Prager material model. In order to reflect the material damping of the system, Rayleigh damping is utilized considering mass and stiffness proportional dampings. In addition, the viscous boundary dashpot elements which consider the criteria of Lysmer and Kuhlemeyer for wave propagation, are placed around the boundaries of the numerical model. The results are examined in terms of both the stresses and displacements. The findings have revealed that the dynamic response of the T shaped cantilever retaining walls is considerably affected by the soil structure interaction.
AtıfScopus3WoS3İncele - EditoryalYalnız künye2019Introduction: Contemporary debates on politics and public administration in postmodern era
Ugur, Ömer; Dogan, Kadir Caner
AtıfScopus2İncele - MakaleYalnız künye2021Scopus SJRQ3Determination of the Chemical Composition, Antioxidant and Antimicrobial Activities of Different Parts of Rosa canina L. and Rosa pimpinellifolia L. Essential Oils
Öz, Mehmet; Deniz, Ilhan; Okan, Onur Tolga; Baltaci, Cemalettin; Karatas, Seyda Merve
Today, the use of essential oils is increasing day by day, and it is considered as raw materials in many industries. Therefore, this study aims to identify the essential oil profile, antioxidant and antimicrobial activity of Rosa canina L. and Rosa pimpinellifolia L. reveal their potential use in the industry. Essential oils that were obtained in 2013-2014 from different parts (flower, leaf, stem, and fruit) of Rosa canina L. and Rosa pimpinellifolia L. by the hydro-distillation method were analyzed by GC/MS. The dominant components in Rosa canina L. were found as trans-geraniol in the flowers (42.08 % for 2013), linalool in the leaves (11.55 % for 2014), and stem (14.91 % for 2013) and vitispirane in the fruits (37.19 % for 2014). The dominant components in R. pimpinellifolia L. were found as heneicosane in the flowers (22.07 % for 2014), γ-elemene in the leaves (30.21 % for 2013), linalool in the stem (14.76 % for 2013) and the fruits, (E)-2-hexenal for those collected in 2013 (14.09 %). The IC50 and FRAP values of the samples ranged from 127.54 to 142.22 μg/g and 121.43 to 296.78 μmol TE/g, respectively. According to the results obtained, both R. canina L. and R. pimpinellifolia L. were found to show poor antioxidant values of DPPH and FRAP. In general, it was determined that the essential oils obtained from different plant parts of both species had a moderate antimicrobial effect against Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, and Pseudomonas aeruginosa.
AtıfScopus17WoS16İncele - MakaleYalnız künye2022Scopus SJRQ2Production of grape pekmez by Ohmic heating-assisted vacuum evaporation
Tunç, Merve Tuçe; Akdoğan, Arda; Baltacı, Cemalettin; Kaya, Zeliha; Odabaş, Halil İbrahim
Pekmez is a concentrated syrup-like food conventionally produced by vacuum evaporation process from sugar-rich fruits. In this study, the applicability of grape pekmez production by ohmic heating assisted vacuum evaporation (ΩVE) method was investigated. Conventional vacuum evaporation (CVE) and ΩVE methods were compared in terms of physicochemical properties, HMF (5-hydroxymethylfurfural) contents, rheological properties, and energy consumptions. ΩVE was run at four different voltage gradients (17.5, 20, 22.5, and 25 V/cm). Total process times for grape pekmez production were determined as 57, 28.5, 32, 39, and 50 minutes for CVE, ΩVE (25 V/cm), ΩVE (22.5 V/cm), ΩVE (20 V/cm) and ΩVE (17.5 V/cm), respectively. Energy consumption of CVE method was higher than ΩVE method for all voltage gradients. Energy efficiency increased as the voltage gradient increased. There was no significant difference between CVE and ΩVE methods for HMF contents. The results show that the ΩVE method could be an alternative to the CVE process for grape pekmez production.
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İncele - MakaleYalnız künye2020Scopus SJRQ4Soil geochemistry study of the listvenite area of ayvacik (Çanakkale, Turkey)
Vural, Alaaddin; Aydal, Doğan
Objective of this study is to use soil geochemistry surveys using statistical methods for the exploration of possibly gold mineralization related to Alakeçi listvenite area (Bayramiç, Çanakkale, Turkey). In the scope of soil geochemistry, about 350 soil samples were analyzed and evaluated for nine elements including gold. Element concentrations for Cu, Pb, Zn, As, Sb, Mo, Ni, Co and Au (all element except Au in ppm, Au in ppb) were 10-265, 10-90, 15-545, 5-800, 2-60, 4-8, 10-6300, 15-1255 and 40-300 respectively. The gold concentrations were comparatively detected in low value than important ore deposit and exhibited no correlation with other elements (except Mo). However, positive correlation was observed between Cu and Zn; Sb and As; Mo with As and Sb; Au and Mo; Ni and Co. In literature, Cu, Zn, As, Sb and Mo were widely used as pathfinder elements for exploration of gold mineralization. So, these elements were accepted as pathfinders in this study and their distribution maps were prepared. The element distribution maps for pathfinder elements and gold displayed remarkable zoning in the central to southeast site of the area connected with tectonic lines and lithological borders. So, in conclusion, this part in the area needs to be investigated in detailed with geophysics and drilling methods for blind gold mineralization.
AtıfScopus6OpenAlex4İncele - MakaleYalnız künye2020Scopus SJRQ2An EEG-based stereoscopic research of the PSD differences in pre and post 2D&3D movies watching
Manshouri, Negin; Maleki, Masoud; Kayikcioglu, Temel
Despite knowing the reality of three-dimensional (3D) technology in the form of eye fatigue, this technology continues to be retained by people (especially the young community). To check the influences of the human brain's power spectrum density (PSD) pre and post a 2D and 3D movie watching, a five-member test group was arranged. In this study, electroencephalogram (EEG) was used as a neuroimaging method. EEG recordings of five individuals were taken both before and after watching 2D and 3D movies. The main framework of this study was to analyze the effects of power spectrum density (PSD) of the human brain by testing all EEG frequency bands before and after 2D and 3D movie watching, also to determine effective brain lobes, and consequently, EEG channels. After 2D/3D EEG recording, this record was divided into three stages for analysis. These stages consisted of Relax, Watching, and Rest. This benchmarking analysis included I) before and after watching the 2D movie (R2b and R2a), II) before and after watching the 3D movie (R3b and R3a), and III) after watching the 2D/3D movie (R2a and R3a). In the Relax and Rest stages, the 2D/3D EEG power differences in all channels of brain regions for the five EEG bands, including delta (δ), theta (θ), alpha (α), beta (β), and gamma (γ), were analyzed and compared. The PSD based on short-time Fourier transform (STFT) was used to select the dominant bands in this study. Feature extraction was performed on the preprocessed EEG signals using STFT and discrete wavelet transform (DWT). In the 2D analysis, δ, θ, α, and β acted as dominant bands, in 3D, δ, θ, and α were dominant bands, and in 2D/3D, δ and α were selected as meaningful and dominant bands. Partial least-squares regression (PLSR) and support vector machine (SVM) classification algorithms were considered in order to classify the obtained R2a and R3a EEG signals. After the dominant band selection, the correct choice of effective channel combinations in these bands resulted in the percentage of high success of classifiers for Stage III. Taking into account the optimum number of channels, the best percentage of classification accuracy for the average of PLSR and SVM classification results by considering the best channels of SVM and DWT feature extraction method is 91.83% and 80.73% respectively.
AtıfScopus56WoS43İncele - MakaleAçık Erişim2019Scopus SJRQ3Employees’ opinions on critical success factors and performance criteria in disaster and emergency management
Sahinoz, Saime; Yaprak, Unal; Sahinoz, Turgut
Objective: To evaluate the critical success factors at disaster and emergency management and to analyse their impact on performance to guide the managers and decision makers. Methods: This was a cross-sectional study. It included all staff working in the fire brigade, 112 Emergency, Disaster and Emergency Management Authority and Red Crescent institutions serving in emergency situations in five provinces (Rize, Artvin, Trabzon, Gümüşhane, Bayburt) in the Eastern Black Sea region of Turkey. One province (Gümüşhane) was selected by cluster sampling method. Questionnaire which is the data collection method in the study was applied between 08/01/2016-02/02/2016 to all of the staff working in the fire brigade, 112 Emergency, Disaster and Emergency Management Authority and Red Crescent institutions serving in emergency situations in Gümüşhane province. Results: It has been found out that there is a significant and positive relationship between all of the critical success factors, planning, response and recovery criteria, and performance variance. Conclusions: The presence of well-planned emergency aid systems in the institutions or organizations involved in this area is an element of success. For this reason, this factor should be given more importance.
AtıfScopus2WoS2OpenAlex2İncele - Kitap BölümüYalnız künye2020A discussion on the possible impact of cryptocurrencies on state sovereignty
Karaaslan, Ibrahim
- MakaleYalnız künye2004Scopus SJRQ2Magma interaction recorded in plagioclase zoning in granitoid systems, Zigana Granitoid, eastern Pontides, Turkey
Karsli, Orhan; Aydin, Faruk; Sadiklar, M. Burhan
Plagioclase crystals characterized by compositional zoning are typical of the Zigana Granitoid (ZG), NE Turkey. The zoned crystals, which show textural equilibrium with the assemblage quartz + plagioclase + K-feldspar + hornblende + biotite + pyroxene, + magnetite + ilmenite, exhibit oscillatory zoning. The zoned plagioclase crystals, ranging in size from 3 to 6 mm, are oval and larger than normal lath-shaped crystals. The zoned crystals are divided petrographically into two main types: (i) crystals zones only at their rims, with spongy cores; and (ii) completely zoned ones. Composition of the zoned crystals ranges from An23 (oligoclase) to An70 (labradorite). Plagioclase crystals with oscillatory zoning are governed by strong substitution mechanisms of Ca2+ ⌊ Na+, Al 3+ ⌊ Sl4+ and weak substitution of Fe3+ for Sl4+. The Fe2O3 (t) (wt %) contents of the subject plagioclases increase with increasing An content. The petrographic and compositional changes from rim to rim (oscillatory zoning), and positive correlation between Fe2O3(t) (wt %) and An (mol %) contents of the zoned plagioclases, suggest recurrent mafic magma injection into a felsic magma chamber, and thus magma interaction as a dominant magmatic process during the evolution of the Zigana Granitoid (ZG).
AtıfScopus36İncele - MakaleYalnız künye2009Scopus SJRQ1Stochastic finite element analysis of structural systems with partially restrained connections subjected to seismic loads
Çavdar, Özlem; Bayraktar, Alemdar; Çavdar, Ahmet; Kartal, Murat Emre
The present paper investigates the stochastic seismic responses of steel structure systems with Partially Restrained (PR) connections by using Perturbation based Stochastic Finite Element (PSFEM) method. A stiffness matrix formulation of steel systems with PR connections and PSFEM and MCS formulations of structural systems are given. Based on the formulations, a computer program in FORTRAN language has been developed, and stochastic seismic analyses of steel frame and bridge systems have been performed for different types of connections. The connection parameters, material and geometrical properties are assumed to be random variables in the analyses. The Kocaeli earthquake occurred in 1999 is considered as a ground motion. The connection parameters, material and geometrical properties are considered to be random variables. The efficiency and accuracy of the proposed SFEM algorithm are validated by comparison with results of Monte Carlo simulation (MCS) method.
AtıfScopus6WoS5OpenAlex6İncele - MakaleAçık Erişim2020Scopus SJRQ1Solar irradiation on the rear surface of bifacial solar modules: a modeling approach
Durusoy, Beyza; Ozden, Talat; Akinoglu, Bulent G.
The transition in the energy sector has started with the growing population leading to the growing energy demands. The use of photovoltaic (PV) technologies has become a crucial way to meet energy demand. There are many ongoing studies for increasing the efficiency of commercial PV modules. One way to increase the energy yield of the PV modules is to use bifacial solar panels by capturing the rear side illumination as well. One of the challenges for estimating the bifacial module performances is to calculate the solar irradiation impinging on the rear side. Many models presented up to now require high computational power, and they are challenging to implement real-life conditions. In this paper, a simple physical modeling approach is presented to calculate the rear side solar irradiation incident on the bifacial modules. For the rear side irradiance estimation, the maximum difference between the measured and calculated rear side irradiance value is approximately 10 W/m2. The model does not require high computational skills since it is neither focused on the view factor nor ray tracing methodologies but instead uses solar geometry. The yield of the module is also modeled, calculated, and compared with the measurements.
AtıfScopus59WoS44OpenAlex60İncele - MakaleYalnız künye2021Scopus SJRQ4Chemical composition and biological activities of volatile oils of arabis alpina l. Ssp. alpina
Ucuncu, O.
This work reports volatile constituents, antimicrobial and antioxidant activity of volatile oils from the air-dried flower and aerial parts (APs) of Arabis alpina L. ssp. alpina. The volatile components of flower and aerial parts (stem + leaf) were investigated by means of hydrodistillation in Clevenger type apparatus and GC/MS/FID analysis. Fifty-one and fifty-three compounds in the volatile oils of flower and APs of A. alpina were identified. Terpene derivatives were the major volatiles in both oils. Hexahydrofarnesyl acetone was the main component of flower oil and APs oil in ratios of 16.27% and 26.94%, respectively. Additionally, both flower and APs essential oils were investigated for their antimicrobial activity against twelve bacteria and five fungi, using agar dilution method and antioxidant activities by using DPPH˙, ABTS˙+ and Folin-Ciocalteu assays. Flower oil was effective against B. subtilis and B. cereus even at 100µg/mL. The amount of total phenolic, %DPPH˙ scavenging activity and ABTS˙+ scavenging activity were found as 485.60±7.28 mg/mL GAE, 49.85±1.22% and 166.43±12.05µM Trolox equivalent, respectively. Flower oil exhibited antimicrobial effect against gram positive bacteria especially, and moderate antioxidant activity.
AtıfScopus3WoS2İncele - Kitap BölümüYalnız künye2021Environmental Policies, Climate Change Perception and Trust
Ugur, Candan Yılmaz
- MakaleYalnız künye2021Scopus SJRQ1The Effect of Progressive Muscle Relaxation Exercises on Pain on Patients with Sickle Cell Disease: Randomized Controlled Study
Kazak, Aysun; Ozkaraman, Ayse
Purpose: The study aimed to evaluate the effect of progressive muscle relaxation exercises on pain in patients with sickle cell disease. Materials-Method: This randomized controlled interventional study was conducted in a hospital in Mersin, Turkey between October 2017 and July 2018. The study sample comprised 58 patients who were aged >18 years, conscious, had sickle cell disease, reported pain, and were treated with non-opioid or weak opioid analgesic based on the physician's recommendation (treatment group = 29, control group = 29). Data were collected by the individual presentation form and visual analog scale. During the study, both groups were treated with analgesics prescribed by the physician for three days. In addition to the analgesics, the treatment group was performed progressive muscle relaxation exercises for 30 minutes whereas the control group was rested. Pain level of both groups was evaluated at three time points every day for three days. In the study, frequency distributions and descriptive statistics were presented for categorical and numerical variables, respectively. Chi-square analysis, independent samples t-test, Mann–Whitney U test, three-way ANOVA, and Sidak test were used to analyze the difference between the variables. Results: The mean age of the patients was 29.59 ± 6.94 years, and 53.4% of the patients were female and 69% were single. The mean pain score of the treatment group at the third time point on days 1, 2, and 3 was significantly lower than the control group (p <.05). There was no statistically significant difference between the two groups in terms of coping methods for pain, pain location, and complaints accompanying pain (p >.05). Conclusion: Progressive muscle relaxation exercises were found to be effective in the pain management of patients with sickle cell anemia.
AtıfScopus7WoS5OpenAlex16İncele - MakaleYalnız künye2020ANALYSIS OF RANDOM DISCRETE TIME LOGISTIC MODEL
Merdan, Mehmet; Şişman, Şeyma
In this study, the behavior of the logistic difference model is investigated under random conditions using discrete probability distributions. The logistic difference model consists of parameters that depend on the population models to be used. For the study of random difference equation population models, the parameters are treated as random variables which constitutes the basis of the study. Random models were created using Uniform, Bernouilli, Binom, Negative Binomial (or Pascal), Geometric, Hypergeometric, Poisson distributions and their numerical characteristics are obtained through their simulations. Then, the results showing random numerical characteristics such as expected value, variance, standard deviation, coefficient of variation and confidence intervals were obtained with MATLAB package program. Analysis of random logistic difference model is given with the help of graphics and tables.
AtıfScopus6WoS6İncele - MakaleYalnız künye2020Scopus SJRQ2Reading comprehension, Mathematics self-efficacy perception, and Mathematics attitude as correlates of students’ non-routine Mathematics problem-solving skills in Turkey
Öztürk, Mesut; Akkan, Yaşar; Kaplan, Abdullah
Literature that investigates the factors affecting problem-solving evaluates the cognitive and affective components, such as reading comprehension, metacognition, Mathematics anxiety, Mathematics attitude and Mathematics self-efficacy. Recently, studies have shown that Mathematics attitude and Mathematics self-efficacy as affective factors, and reading comprehension as a cognitive factor could play a crucial role in the problem-solving of middle school students. This study investigated the influence of reading comprehension skill, Mathematics self-efficacy perception and Mathematics attitude on non-routine Mathematics problem-solving skills. It is hypothesized that non-routine problem-solving skills are related to reading comprehension skills, Mathematics self-efficacy perception and Mathematics attitudes. To achieve this aim, a reading comprehension skill test, a Mathematics self-efficacy perception scale, a Mathematics attitude scale and a non-routine problem-solving skill test were applied. The instruments were completed by 362 middle school students. A correlation analysis was used to determine the relationship of variables on non-routine problem-solving skills, and the predictive effects of the predictor variables on non-routine Mathematics problem-solving skills were examined by hierarchical regression analysis. The analysis also showed that for middle-school students’ non-routine Mathematics problem-solving skills, all related factors–reading comprehension, Mathematics self-efficacy perception and Mathematics attitude were significant. Reading comprehension skills and Mathematics self-efficacy perception significantly predicted problem-solving skills, and both predictors explained a total of 22% of the total variance.
AtıfScopus55WoS30OpenAlex116İncele
