Yayınlar
Koleksiyondaki öğeler
- MakaleAçık Erişim2021Temporal monitoring of land use/land cover change in Kahramanmaraş city center
Aliyazicioglu, Kubra; Beker, Fatmanur; Topaloglu, Raziye Hale; Bilgilioglu, Burhan Baha; Comert, Resul
Irregular urbanization causes problems such as decrease in fertile agricultural areas, irregular industrialization and urbanization. To provide a healthier life opportunity for future generations without disturbing nature, it is essential to determine the temporal changes in land use and to make land management plans accordingly. In this study, land use/land cover (LULC) change occurred in Kahramanmaras province within 30 years was investigated by remote sensing and integration of Geographic Information Systems. Landsat satellite images of 1988-1998-2008-2018 were obtained for the production of LULC maps. Each image was classified according to supervised classification approach using the support vector machines (SVMs) algorithms. The confusion matrix was created for each year to examine the accuracy of the LULC maps. The overall accuracy of the thematic maps was obtained as 91.76%, 93.56%, 86.89% and 88.29%, respectively. Also, Kappa values of thematic maps for each year were obtained as 0.88, 0.91, 0.81 and 0.84, respectively. When the results were examined, the development of industry in the city area and the construction of the airport contributed to the development of the social and economic structure of the city. The increase in the number of housing in the related regions has led to an increase in the amount of urban areas and a decrease in agricultural areas.
AtıfScopus9OpenAlex13TR Dizin4
İncele - BildiriAçık Erişim2021GIS-BASED OPTIMUM SITE SELECTION for SOLAR ELECTRIC VEHICLE CHARGING STATION: ANKARA-ISTANBUL HIGHWAY CASE
Hisoglu, Seyit; Comert, R.
Energy sources are divided into renewable and non-renewable sources. It can be seen that non-renewable energy resources are not adequately meeting the increased demands of worldwide technological developments, increasing population, and global consumption. Therefore, the demand for renewable resources is increasing day by day. When it comes to the use of non-renewable carbon-based fossil fuels, one of the first areas that come to mind is undoubtedly the Automotive sector. Today, it is realized that one of the main reasons for the lack of electric motor cars compared to petroleum fuelled cars, is the scarcity of electric vehicle charging stations and the difficulty of their accessibility. In this study; an analysis of solar-powered electric charging stations site selection was carried out for electric vehicles. The Ankara-Istanbul highway, which has a high traffic density, was chosen as the sample route for the study. Within the scope of the study, the areas where stations can be installed on the highway were carried out using the Multi-Criteria Decision Making Method with the help of Geographic Information System. Solar radiation, slope, aspect, land use/land cover, traffic volume and proximity to the road, criteria of the route, and site selection analysis were determined as input data. The maps of the determined criteria were arranged according to the study area and prepared for analysis. The criteria maps obtained were reclassified according to the above-mentioned criteria and scoring system. After the reclassification process, the weighting of each criteria which affect the analysis was determined by the researched literature and an overlapping process was carried out. According to the results map produced as a result of the overlay analysis, the appropriate area has been determined for the electric charging stations working with solar energy. On the defined route within the scope of the study, a proposal has been made for a total of 13 stations, 8 in Ankara, 3 in Bolu, 1 in Kocaeli, and 1 in Istanbul. This study, it is aimed to encourage automobile users to make greater use of electric motor vehicles, which would be a more environmentally friendly and sustainable choice, and ultimately more economical.
AtıfScopus6OpenAlex3İncele - MakaleAçık Erişim2020Scopus SJRQ4Proteolytic, lipolytic and amylolytic bacteria reservoir of Turkey; cold-adaptive bacteria in detergent industry
Muslu, Selman; Genc, Berna; Adiguzel, Mahmut; Albayrak, Seyda; Adiguzel, Ahmet
Enzymes which would be active in cold conditions can be used in a wide range of fields from molecular biology to detergent industry due to their low processing capacity and high activity. In this study, sixty cold-adapted bacteria were isolated from water and sludge samples collected from Erzurum and Van provinces. Identification of eight isolates by molecular [(GTG)5-PCR and 16S rRNA sequencing] techniques and tests for temperature (4-35°C), pH (3-11) and salt (2-15% (w/v) requirements were performed. These bacteria were belonging to Pseudomonas chlororaphis subsp. aureofaciens (SM011A), Psychrobacter faecalis (SM012D), Rahnella aquatilis (SM015A), Shewanella putrefaciens (SM018A), Pseudomonas lactis (SM0110A), Flavobacterium chryseum (SM0112E), Exiguobacterium mexicanum (SM0117A) and Glutamicibacter arilaitensis (SM0118A). The physicochemical requirements for all isolates ranged between 4-25°C, pH 5-7 and 2-15% salt (NaCl) concentration. However, E. mexicanum did not require salt in growth medium. All bacteria were evaluated for protease, lipase and amylase enzymes and all were found to be multiple enzyme producers. The eight isolates were identified from the resources of Turkey, for the first time and enzyme production abilities of some isolates to produce enzymes were declared. The originating of the producers of these enzymes from Turkey shows that Turkey has a remarkable reservoir for cold-adaptive microorganisms and these microorganisms will make important contributions to the detergent industry worldwide.
AtıfScopus6WoS5OpenAlex9
İncele - Kitap BölümüYalnız künye2022Digital Marketing and Digital Marketing Applications in the Asian Tourism Industry
Polat, Eray
Technology takes the place more and more in human life and directs it. Therefore, it is no longer possible to imagine that marketing, which has a fundamental goal to meet the needs and desires of people, is independent of the technology that has entered such human life. The primary objective of this section is to provide a conceptual framework for digital marketing, which has become increasingly pronounced in recent years. By doing so, the evolution of the marketing mix and digital marketing practices is discussed in particular. The second important objective in this section is to present examples of digital marketing practices carried out by tourism enterprises in Asian countries. When the relevant literature is examined, it can be said that in the context of the Asian tourism industry, this area is left under-researched. In this context, secondary data, generated from the existing literature, were used to collect data. Findings show that digital marketing applications in Asian countries are not yet implemented sufficiently and need to be developed. This issue will be more important for the Y and Z generation tourists who are more deeply related to technology as it is important today.
AtıfScopus7OpenAlex5İncele - MakaleAçık Erişim2022Scopus SJRQ3Comparison of deep learning and regression-based MPPT algorithms in PV systems
Karabi̇Naoğlu, Murat Salim; Çakir, Bekir; Başoğlu, Mustafa Engin; Kazdaloğlu, Abdülvehhab; Güneroğlu, Aziz
Solar energy systems (SES) and photovoltaic (PV) modules should be operated at the maximum power point (MPP) to achieve the highest efficiency in the energy generation processes. Maximum power point tracking (MPPT) applications using conventional methods may not be able to follow the global MPP (GMPP) of the PV system under changing atmospheric conditions and they could oscillate around the local MPP. In this study, a machine learning and deep learning (DL) based long short-term memory (LSTM) model is proposed as an innovative solution for MPPT. Contrary to the traditional MPPT applications using current and voltage sensors, the output resistance of the PV module estimation was made by using environmental parameters (such as temperature and radiation) and artificial intelligence algorithms in this study.The LSTM model was compared with artificial neural networks (ANN) and regression methods regarding mean square error (MSE), root mean square error(RMSE) and mean absolute error (MAE) parameters. It has been determined that the LSTM model has a better performance and could more successfully follow MPP compared to the other methods. Finally, after the comparison with the ANN method, it is proved that LSTM gives 37%, 21%, and 31% more successful MSE, RMSE, and MAE results, respectively.
AtıfScopus27WoS18OpenAlex23İncele - MakaleAçık Erişim2021Scopus SJRQ1Analysis of salt lake volume dynamics using sentinel-1 based SBAS measurements: A case study of lake Tuz, Turkey
Bilgilioğlu, Burhan Baha; Erten, Esra; Musaoğlu, Nebiye
As one of the largest hypersaline lakes, Lake Tuz, located in the middle of Turkey, is a key waterbird habitat and is classified as a Special Environmental Protection Area in the country. It is a dynamic lake, highly affected by evaporation due to its wide expanse and shallowness (water depth <40 cm), in addition to being externally exploited by salt companies. Monitoring the dynamics of its changes in volume, which cause ecological problems, is required to protect its saline lake functions. In this context, a spatially homogeneous distributed gauge could be critical for monitoring and rapid response; however, the number of gauge stations and their vicinity is insufficient for the entire lake. The present study focuses on assessing the feasibility of a time-series interferometric technique, namely the small baseline subset (SBAS), for monitoring volume dynamics, based on freely available Sentinel-1 data. A levelling observation was also performed to quantify the accuracy of the SBAS results. Regression analysis between water levels, which is one of the most important volume dynamics, derived by SBAS and levelling in February, April, July and October was 67%, 80%, 84%, and 95% respectively, for correlation in the range of 10–40 cm in water level, and was in line with levelling. Salt lake components such as water, vegetation, moist soil, dry soil, and salt, were also classified with Sentinel-2 multispectral images over time to understand the reliability of the SBAS measurements based on interferometric coherence over different surface types. The findings indicate that the SBAS method with Sentinel-1 is a good alternative for measuring lake volume dynamics, including the monitoring of water level and salt movement, especially for the dry season. Even though the number of coherent, measurable, samples (excluding water) decrease during the wet season, there are always sufficient coherent samples (>0.45) over the lake.
AtıfScopus4WoS5OpenAlex6İncele - BildiriYalnız künye2021Scopus SJRQ4Sequential Pattern Mining Method for Predictive Maintenance of Large Mining Trucks
Kahraman, Abdulgani; Kantardzic, Mehmed; Kahraman, M. Mustafa; Kotan, Muhammed
In recent decades, various solutions had been sought for reducing operating costs while increasing the production of minerals in mining operations. Equipment health monitoring technologies had been used for monitoring and increasing the availability of machines. However, the data obtained from these technologies had only been used for monitoring the equipment health, and not for the prediction of failures. In this paper, it was relied on alarms and signals collected through real-time health monitoring technologies for predicting crucial mining truck failures. Sequential Pattern Mining (SPM) Method for Predictive Maintenance had been developed and implemented as a methodology to discover which group of alarms and signals might be related to specific truck failures. The results indicate that the SPM method is able to detect machine failures of trucks with high accuracy with an average 96%. The proposed methodology may reduce the maintenance time, and the expenditures caused by truck breakdowns in the mining industry.
AtıfScopus3OpenAlex4İncele - MakaleAçık Erişim2020Scopus SJRQ3Determining the quality of life and the sleep quality in patients with benign prostate hyperplasia
Kulakaç, Nurşen; Sayılan, Aylin Aydın
Research question: How is the quality of life and quality of sleep affected in patients with benign prostatic hyperplasia?. Research problem: The aim of this study was to evaluate the quality of life and quality of sleep in patients with benign prostatic hyperplasia (BPH) and to identify the relationship between them. Nocturia is one of the main symptoms associated to BPH, causing significant sleep disturbances, including sleep interruptions. Such sleep interruptions may significantly impair quality of life. Literature review: The assessment of nocturia and its impact on quality of life and sleep quality in patients living with benign prostatic hyperplasia (BPH) has been poor in terms of clinical research; moreover, there is a lack of specific methods to assess this impact. Methodology: The sample of this descriptive study consisted of all patients with the diagnosis of BPH who were admitted to the urology outpatient clinic of a state hospital in Turkey. The data were collected from 212 patients with BPH who accepted to participate in the study in January-June 2018. All patients gave consent prior to inclusion in the study. The Pittsburgh Sleep Quality Index and the WHOQOL-BREF (World Health Organization Quality of Life Scale - Brief Form) were used as the principle data collection tools. Percentage, t test, correlation and one-way variance analysis test were used to evaluate the data. Results: The mean age of the patients was 67.50 ± 8.89 years and 63.2% of them were first diagnosed with benign prostatic hyperplasia 2.13 years ago. The lowest and the highest average scores that the patients obtained from the WHOQOL-BREF were their social and environmental domains scores, respectively. In all, 20.2% of the patient were found to have poor sleep quality (global score ≥ 5). The results showed that there was a positive correlation between the mean scores of the sleep quality of the patients and their quality of life physical domain subscale. It was also found that there was a significant negative correlation between night urination and the sleep quality in BPH patients (P <.05). Conclusions: It was determined that low quality of life in BPH patients is associated with low sleep quality. Personal characteristics, frequent night urination and working status are important determinants of the relationship between quality of life and sleep quality.
AtıfScopus2WoS2OpenAlex1İncele - MakaleAçık Erişim2022Scopus SJRQ3Adaptation of the pain management self-efficacy questionnaire into Turkish; [Ağrı yönetimi öz yeterlilik ölçeğinin türkçeye uyarlanması]
Aydin Sayilan, Aylin; Eşki̇N Bacaksiz, Feride; Seyhan Ak, Ezgi; Kulakaç, Nurşen; Macindo, John Rey B.
Objectives: The aim of this study is to examine the Turkish validity and reliability of the Pain Management Self-Efficacy Questionnaire (PMSEQ). Methods: The study was carried out descriptively and methodologically between September and December 2018 with 214 nurses and 248 nursing students. The data were collected using the descriptive characteristics form and the PMSEQ. Results: Cronbach’s alpha internal consistency coefficient was 0.90 in the total scale. In repeated measurements to test time reliability, there was no statistically significant difference between the two measurements (t=0.320, p=0.751), and there were a high power and positively highly significant relationship (r=0.997, p<0.001). Conclusion: Turkish version of the PMSEQ can be used as a valid and reliable scale in assessing the self-efficacy of clinical nurses and nursing students in pain management.
AtıfScopus9WoS12OpenAlex8TR Dizin3
İncele - MakaleYalnız künye2020Scopus SJRQ4Characterization and selection of alfalfa cultivars based on agronomic and quality characteristics information from continental climatic conditions of turkey
Karakoy, Tolga; Nadeem, Muhammad Azhar; Ton, Aybegun; Celisiz, Yeter; Anlarsal, Adem Emin; Hatipoglu, Rustu
Alfalfa is one of the most important crops mainly grown for forage and hay production in the world. Present study was aimed to investigate the green herbage and hay yield as well as some quality parameters such as acid detergent fiber (ADF), neutral detergent fiber (NDF), digestible dry matter (DDM), crude protein, dry matter contents, organic matter, crude oil and raw fiber of 9 different alfalfa cultivars. This study was conducted during two consecutive years (2015 and 2016) at two locations in Turkey (Sivas -Center and Sivas-Altinoluk). The mean values of ADF, NDF, DDM, crude protein (CP), green forage yield and dry forage yield were 43.73%, 52.69%, 50.70%,19.71%, 59163 kg ha- 1 and 13866 kg ha- 1 respectively. Dry forage yield reflected a positive and highly significant correlation with plant height, number of tillers and fresh forage yield. The varieties called Delta and Azzura performed very well for both locations during the whole period of study and also expressed a great level of winter resistance. Kayseri is a local cultivar in Turkey and it is revealed to be poor in terms of all the studied traits. According to the results of the study, it was concluded that the cultivars, Delta and Azzura, could be successfully grown in the continental climate regions of Turkey, and they could be also used in the breeding program of alfalfa to develop alfalfa varieties with high winter resistance and high yield and quality of forage.
AtıfScopus2İncele - MakaleAçık Erişim2020Scopus SJRQ3Determination of physicochemical and microbiological properties and fatty acid composition of butter produced in Trabzon, Turkey
Akgül, Halil İbrahim; Şengül, Mustafa; Ürkek, Bayram; Kotan, Tuba Erkaya
In this study, the some physicochemical properties, fatty acid compositions and microbiological properties of butter samples were studied. Butter samples (n = 30) were randomly collected from different local markets. Thus, butter samples were evaluated in terms of Turkish regulations, food safety and quality. The mean values of the butter samples for peroxide value (PV), iodine value (IV), saponification value (SV), Polenske value, Reichert-Meissl (RM) and Refractive index (RI) values were determined as 0.85 mEqO2 kg-1, 30.03, 220.09, 1.30, 25.60 and 1.4611, respectively. The moisture and fat values were not in harmony with Turkish Food Codex Butter, Other Milk Fat Based Spreadable Products and Anhydrous Milkfat Notification (the highest moisture content 16%, the lowest fat content 80%) in 23 and 13 butter samples, respectively. The salt values were coherent with Turkish Food Codex in all butter samples. Conjugated linoleic acid (CLA) rate of the butter samples was ranged from 0.15 to 1.32%. The average values of coliforms, total aerobic mesophilic bacteria (TAMB) and mould and yeasts counts were determined as 1.67, 6.33 and 5.22 log CFU g-1, respectively.
AtıfScopus13WoS10OpenAlex13İncele - MakaleAçık Erişim2020Scopus SJRQ2The Mediator Role of Academic Resilience in the Relationship of Anxiety Sensitivity, Social and Adaptive Functioning, and School Refusal With School Attachment in High School Students
Seçer, İsmail; Ulaş, Sümeyye
School has an important function in providing the environment for young people to acquire many skills and knowledge required by contemporary life, but the problems of attachment to school and problematic attendance all over the world reveal an increasing statistic. It is thought that some negative processes such as anxiety sensitivity, social and adaptive functioning, and school refusal can affect this problem. On the other hand, it is considered that the academic resilience of young people has an important protective function in terms of these risk factors. For this purpose, the mediator role of academic resilience between anxiety sensitivity, social and adaptive functioning, and school refusal and school attachment were examined in a Turkish sample of 452 high school students. In the process of data collection, the school refusal assessment scale, social and adaptive functioning scale, and academic resilience scale were adapted and used in the Turkish culture. In the data analysis, the structural equation model was used to determine the direct and indirect predictive effects between the variables. The results of the study showed that academic resilience fully mediated the relationship between anxiety sensitivity and school attachment, whereas it partially mediated the relationship between social and adaptive functioning and school refusal and school attachment. Based on the results of the study, it was evaluated that high academic resilience has a strong protective function against the problems of negative school attachment and problematic school absenteeism among young people, and this finding was discussed within the context of literature.
AtıfScopus45WoS22OpenAlex54İncele - MakaleYalnız künye2021Scopus SJRQ2A copula approach for sea level anomaly prediction: a case study for the Black Sea
Yavuzdoğan, Ahmet; Tanır Kayıkçı, Emine
Forecasting future sea levels is of great importance in terms of the conservation of coastal areas, monitoring and forecasting coastal ecosystems, and the maintenance and planning of coastal structures. In addition, highly accurate sea level forecasts allow adequate water management policies and coastal infrastructures to be developed. Today, many methods, such as harmonic analyses, artificial neural networks and support vector machines, are used to predict sea level anomalies. In this study, a novel approach based on Copula functions is presented for the prediction of sea level anomalies. The primary purpose of this study is to examine the applicability and capability of Copula-based prediction models in predicting short-term variations in the sea level. The minimum 95% correlations and minimum 22 mm RMSE values in sea level anomaly predictions during the testing period indicate that the Copula approach can be a powerful tool in the prediction of sea level anomalies.
AtıfScopus12WoS10OpenAlex10İncele - MakaleAçık Erişim2021Scopus SJRQ1Investigation of the Effect of the Dataset Size and Type in the Earthquake-Triggered Landslides Mapping: A Case Study for the 2018 Hokkaido Iburu Landslides
Comert, Resul
Rapid mapping of landslides that occur after an earthquake is important for rapid crisis management. In this study, experimental research was conducted on the size of the model area and the data types used in developing classifiers for the supervised classification approaches used in rapid landslide mapping. The Hokkaido Iburu earthquake zone that occurred on September 6, 2018, was selected as the study area. PlanetScope pre-event and post-event images and ALOS-PALSAR Digital Elevation Model (DEM) were used in the analysis processes. In this context, five model areas with different sizes and one test area were determined. Object-based image analysis (OBIA) was used as a landslide mapping approach. Random Forest classifier, which is a supervised classification algorithm, was performed in the mapping of image objects produced by the segmentation stage of OBIA. Two different data sets were created for landslide mapping: change-based dataset and post-event dataset. The change-based dataset is generated from change data such as the difference of normalized difference vegetation index (δNDVI), change detection Image (CDI), princiable component analysis (PCA), and Independent component analysis (ICA) which are used in change detection applications. The post-event dataset was created from data generated from post-event image bands. When the obtained results were examined, higher accuracy results were obtained with the post-event dataset. Increasing the size of the model area, in other words, increasing the training data slightly increases the accuracy of landslide mapping. However, a model area that represents the region to be mapped in small sizes to make rapid decisions provides a 94% F-measure accuracy for earthquake-triggered landslide detection.
AtıfScopus13WoS12OpenAlex13İncele - MakaleYalnız künye2022Scopus SJRQ2Chemical Composition and Antimicrobial Properties of Essential Oils Obtained from the Resin of Picea orientalis L.
Öz, Mehmet
This study aims to evaluate the chemical composition and antimicrobial (antibacterial and antifungal) properties of the essential oil subtracted from the oleoresins, which were obtained from the stem of the Picea orientalis naturally grown in Turkey. The essential oil of the resin was obtained through the hydrodistillation method in a Clevenger type device, and it was analyzed with GC-MS/FID. The structure of 74 compounds that were found in the essential oil was elucidated by comparing with literature data and the database in the appliance. Limonene (53.40%), β-pinene (20.74%) and α-pinene (14.51%) were determined to be the major components. The highest class of compounds in resin essential oils was identified as monoterpene hydrocarbons. The antimicrobial activity of the essential oil was investigated with the agar well diffusion method against 25 microorganisms, including 13 gram-negative, 7 gram-positive bacteria and 5 yeast-molds. As the results of the analysis, the highest antibacterial activity was recorded against S. typhimurium from gram-negative bacteria with inhibition zone ranging as (13.70±0.10-9.70±0.10 mm) and S. aureus from gram-positive bacteria with inhibition zone ranging as (9.30±0.10-6.80±0.10 mm). Additionally, the highest antifungal activity was obtained against C. albicans from yeast-molds with inhibition zone ranging as (10.10±0.10-6.10±0.10 mm).
AtıfScopus10WoS6OpenAlex6İncele - Kitap BölümüYalnız künye2020A novel similarity measure for single-valued neutrosophic sets and their applications in medical diagnosis, taxonomy, and clustering analysis
Şahin, Ridvan; Karabacak, Mesut
As a generation of Atanassov's intuitionistic fuzzy set, the single-valued neutrosophic set is an important modeling approach for expressing and processing the inconsistent and indeterminate information very well. Similarity measure is an important tool frequently used in a variety of areas, from clustering analysis to medical diagnosis. Although neutrosophic literature has many similarity measures, they have some disadvantages that do not provide the general conditions of the similarity measure for some specific values. In this chapter, we present a novel similarity measure to handle the relationship between two single-valued neutrosophic sets. It uses a matrix norm and a strictly increasing (or decreasing) binary function called fuzzy implication, and provides axiomatic definition properties of similarity measure. The advantage of using fuzzy implications is that it offers not only different final options to decision-makers but also gives a parameterized class of similarity measures of SVNSs. It is appeared that the developed similarity measure gives better results when compared to other existing similarity measures. Finally, several numerical examples related to pattern recognition, such as medical diagnosis and taxonomy approach, and clustering analysis are performed to demonstrate the practical applicability of the proposed similarity measure.
AtıfScopus17OpenAlex14İncele - MakaleAçık Erişim2021Fuzzy inverse logic: part-1. introduction and bases; [Bulanık ters mantık: kısım-1. giriş ve temeller]
Öztekin, Ertekin
In almost all deterministic and artificial intelligence techniques, for the solution of the scientific problems such as design and control problems, the output estimations are performed depending on manuplations on the values of input variables. With the other words, lots of different values derived from input parameters are tried in order to obtain desired output(s). Contrary to these conventional estimation methods, this study consists of two parts in which a new artificial intelligence method called fuzzy inverse logic(FIL) is developed to determine or estimate the value of the input parameters that give the targeted problem output. In the first part of this study, after providing a brief overview about the method of classical fuzzy logic(FL), the solution approaches and calculation details about FIL are given. In the second part of the study, fuzzy inverse logic method was used to solve one simple mathematical problem and one simple civil engineering problem. After the validity of the developed method was demonstrated by graphics and tables. some evaluations were made about the method.
AtıfScopus2OpenAlex3TR Dizin1İncele - MakaleYalnız künye2021Scopus SJRQ2Neuro sliding mode control of quadrotor UAVs carrying suspended payload
Bingöl, Ö.; Güzey, H.M.
In this paper, a neuro-sliding mode controller (SMC) has been designed for a quadrotor transporting a suspended payload. SMCs are very efficient under uncertain conditions. However, if the uncertain dynamics change over time, SMC gains need to be updated to maintain the tracking performance. This study proposes a neuro-SMC to control a quadrotor UAV carrying a suspended payload in the existence of time-varying uncertain dynamics. Once the accuracy of the proposed controller is demonstrated theoretically using the Lyapunov stability criterion, the effectiveness of the proposed controller is shown in simulation, which confirms the theoretical claims.
AtıfScopus26WoS22OpenAlex28İncele - MakaleYalnız künye2020MODELING OF THREE-PHASE THREE-LEVEL RECTIFIER WITH SPACE VECTOR PULSE WIDTH MODULATION METHOD IN MATLAB/SIMULINK PROGRAM
Yüksek, Halil İbrahim; Ari̇Foğlu, Uğur
Multi-level rectifiers have low harmonic content and electromagnetic interference (EMI). In recent years, especially in medium and high-power applications are increasing use. As the voltage level per switch and switching frequency are low, the multi-level rectifiers have low losses and high efficiency. In this study, three-level neutral point clamped (NPC) rectifier topology with pulse width modulation (PWM) is investigated and the decoupled equations in the d-q synchronous rotating axis of the rectifier are given and a space vector PWM (SVPWM) control algorithm based on the d-q synchronous rotating axis of three-level rectifier is proposed. The control of the whole system is provided by voltage oriented control (VOC) strategy, which enables the realization of control in cascade system with outer voltage and inner current control blocks. This paper is focused on explaining in detail modulus optimum and symmetrical optimum methods used in the design of the inner current and outer voltage PI controllers of the three-level rectifiers, respectively. PI voltage controller is used to keep the rectifier output voltage constant, and PI current controller is used to reduce the harmonic content of the grid current. In addition, a simplified method compared to conventional SVPWM is used to calculate switching times and switching sequences. In this study, three-level rectifier is simulated in Matlab / Simulink with the help of SVPWM. The performance of the circuit has been tested by changing both the load value and the load voltage suddenly and successful results have been achieved.
AtıfScopus3WoS3İncele - MakaleAçık Erişim2021Phytic acid content and in-vitro digestibility of several cereal and legume types treated with different processes
Bektaş, Müberra; Ertop, Müge Hendek
Introduction. The present study aims to determine the relationship between phytic acid (PA) content/digestibility rate of the grains, which are widely consumed in daily diet, and the methods often used in preparing food for consumption. Materials and methods. In this study, the dephytinization effect of soaking (for 12 h), boiling (at 100 °C for 1 h), autoclaving (at 121°C for 15 min), fermentation (at 25-27 ℃), and germination processes on several grains were studied. PA contents, Mineral Digestibility (MD, %), and Protein Digestibility (PD, %) were determined, and their effects comparatively evaluated before and after processes. Results and discussion. There were decreases in PA contents in legumes and cereals for all the methods applied. Fermentation (<800 mg/100 g) of the flour and germination for the other samples (<700 mg/100 g) were found to yield more effective results to PA degradation. Between 20-70% reduction by fermentation and 50-80% reduction by germination of PA contents in the samples were found. Moreover, MD level in cereals, which was especially low before germination, increased up to 2 times after the germination. PD, %, was found to increase with the effect of the processes, except for boiling and soaking. Especially germination process was more effective in tems of PD. Increasing rate of PD for ten bean samples was up to 200%. Wheras the PA contents in the cereal flour samples after their spontaneous fermentation were decreased, their digestibility values were increased statistically (p<0.05). Conclusions. All processes applied such as soaking, fermentation, or heat treatments, which are widely used to preparation of the grains, provide an advantage in dephytinization at different rate. Combined use of techniques such as soaking, and boiling which are used in the preparation of various cereal and legume products for consumption, is also be effective in terms of nutritional quality and their combinations were proposed.
AtıfScopus7WoS5OpenAlex5İncele
