Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Merdan, Mehmet(2)
- Terhan, Meryem(2)
- Türker, Temel(2)
- Acar, Mehmet Cemal(1)
- Acikgoz, Pınar(1)
- Akay, Seref(1)
- Anac, Halil(1)
- Arslan, Metin(1)
- Aymelek, Abdullah(1)
- Cam, Handan(1)
- Demirel, Ugur(1)
- Durmuş, Gökhan(1)
- Efe, Burak(1)
- Efe, Ömer Faruk(1)
- Kaya, Dilek(1)
- Kesemen, Tulay(1)
- Koşmaz, Betül(1)
- Kurt, Mustafa(1)
- Omar, Muhammed Arslan(1)
- Unlu, Ramazan(1)
- Yanik, Yusuf(1)
- Yanık, Yusuf(1)
- Yildirim, Ömer(1)
- Yıldırım, Ömer(1)
- Çalik, Ismet(1)
- Çelik, Ayşenur(1)
- Çullu, Mustafa(1)
- Ökdem, Selçuk(1)
- Özağdaş, Emre(1)
- Özdilek, Hasret(1)
- İlgar, Gamze(1)
- Şüküroǧlu, Ebru Emine(1)
Yayınlar
- MakaleAçık Erişim2025Investigation of Nonstandard Finite Difference for Fractional Order Covid-19 Model
Merdan, Mehmet; Acikgoz, Pınar
This article examines a mathematical model of the Covid-19 type. We demonstrate how the population is impacted by immigration, protection, the mortality, exposure, curing, and interactions between sick and healthy individuals. There are five classifications in our model: exposed, susceptible, infected, quarantined, and recovered. The model is subjected to numerical and fractional analysis in this instance. The numerical analysis is performed using the fractional order non-standard finite difference (NSFD) scheme. The Grunwald-Letnikov numerical approximation technique is used for fractional analysis. The findings are evaluated by simulations using the Matlab tool.
- MakaleAçık Erişim2025Changes of natural frequencies of masonry stone minarets due to temperature and humidity; [Yığma taş minarelerin doğal frekanslarının sıcaklık ve neme bağlı değişimleri]
Aymelek, Abdullah; Yanık, Yusuf; Yıldırım, Ömer; Türker, Temel
It is very important to distinguish the reason of change in natural frequencies of structures either caused by a possible damage or environmental conditions as temperature and humidity. In this study, the changes in the dynamic properties of masonry minarets under environmental effects such as temperature and humidity were investigated. The Minarets of İskenderpaşa, Hacı Kasım and Tavanlı Mosques in Trabzon were monitored by ambient vibration test method, the relationship between natural frequencies and temperature and humidity was tried to be determined. For this purpose, the natural frequencies of these minarets were measured at certain intervals under different temperature and humidity conditions over a period of approximately six months. The vibration measurement system which was developed by our research team was used in the measurements. From the data collected by these measurements, the variation intervals of the natural frequencies (the smallest and the highest values), the percentages of change and their relations with temperature and humidity were revealed. This relationship was determined by using linear-nonlinear simple and multiple regression analyses. From the study, it was found that the natural frequencies change under environmental effects such as temperature and humidity, and this rate of change was approximately 7%.
- MakaleAçık Erişim2024Effect of thickness and melting temperature of phase change material integrated into exterior wall on building energy performance and CO2 emission reduction; [Dış duvara entegre edilen faz değiştiren malzemenin kalınlığı ve erime sıcaklığının bina enerji performansı ve CO2 emisyon azalımına etkisi]
İlgar, Gamze; Terhan, Meryem
In the study, the effect of phase change materials integrated into the building's external wall has been investigated in terms of material type, thickness, and melting temperature of phase change material on the building energy performance for İzmir Province. A villa residential project has been modelled in 3D using DesignBuilder energy simulation software and two different external wall configurations have been designed by changing the position, thickness and melting temperature of the PCMs into the wall. The amount of CO2 emission reductions that PCMs will provide according to the fuel type of the building's heating system has been calculated. Using PCMs in the external wall not only provides high heating and cooling energy savings but also increases thermal comfort indoors by reducing temperature fluctuations. The PCM melting temperature of 23℃ performs quite well compared to other temperatures in both cooling energy and heating energy demand reduction. By increasing the triple thickness of the PCM, 18.81% in heating energy and 22.85% in cooling energy savings can be achieved. Depending on the external wall and phase change material types, different thicknesses and melting temperatures of PCM, annual total energy saving of the phase-change material is calculated between 10,349.50-83,345.98 kJ/m2.year and the annual CO2 emission reduction according to fuel types has been found as 0.672-14.284 kgCO2/m2.year.
- MakaleAçık Erişim2024Design and fabrication of low-cost microsystems for production of chitosan particles; [Kitosan parçacıklarının üretimi için düşük maliyetli mikrosistemlerin tasarımı ve fabrikasyonu]
Akay, Seref; Özdilek, Hasret
Recent research has focused on the methods for administration of medications in a controlled manner while minimizing side effects. Cross-linked hydrogels have wide application area as nanocarriers. There are many approaches for developing suitable methods to produce ideal particles. Advances in microtechnology have been considered as a solution to produce controlled drug delivery systems, however, it is limited due to the necessity for specialized laboratories. In this study, a simple method to produce antibiotic-loaded chitosan particles is proposed. Production was carried out with two different designs, a syringe-based flow focusing system (outer diameter of 1 mm, inner diameter of 120 µm) and microchannel with 250 µm width and 100 µm height fabricated with the computer numerical control (CNC). Sodium Triphosphate (TPP) was used as cross-linking agent for the production of particles and the effects of the concentration and flow rates on the particle formation was investigated. It has been observed that particles can be produced in a syringe-based system, but the resulting particles are not homogeneous. In the studies carried out with CNC microchannel, it was determined by SEM analysis that the obtained particles ranged in size from 39 to 771 nm, and it was seen that the CNC microchannel was more effective at low and equal flow rates (25 µl/min). It has been found that increasing the flow rate and concentration of chitosan increases the particle size. It was determined that Ampicillin loaded particles synthesized with the CNC microchannel exhibited high inhibition against Gram positive and Gram negative bacteria. These results show that the proposed approaches for the design of microsystems can be used in the formation of drug carriers without the need for specialized laboratories and expertise.
- MakaleAçık Erişim2023Geographic information system approach in evaluating the geotechnical properties of soils: A case study of Oymaağaç in Kayseri; [Zeminlerin geoteknik özelliklerinin değerlendirilmesinde coğrafi bilgi sistemi yaklaşımı: Kayseri Oymaağaç örneği]
Acar, Mehmet Cemal; Kaya, Dilek
Kayseri, the ninth biggest city in Turkey, the regions opened to the ongoing construction of residential areas are expanding rapidly parallel to population growth. Soil improvement works are carried out in areas with the poor bearing capacity of foundations and in regions that are not suitable for safe construction. This event causes severe economic losses in urban development. This study proposes a (Geographic Information System) GIS-based approach to comprehensively understand the research area's underground conditions, predetermine the zones opened for construction by considering the parameters affecting the foundation of the buildings, and create an informative geotechnical model with visualization technology. For an exemplary application, a database was created with ArcGIS in the Kayseri Oymaağaç location, and geological and geotechnical data were combined. The soil properties of this one million five hundred thousand square meter area opened for new settlement were analyzed in a GIS environment. The variation of SPT-N values measured in 60 boreholes in the field with depth, soil types, groundwater levels, and Vs data were used to combine the data, and related maps were drawn. Then, maps of the liquefaction of the soil in a possible earthquake and visual maps showing the bearing capacity of the foundations were created. This study will offer the best and most reliable land-use scenarios and in situ soil properties to decision-makers such as engineers, government agencies and disaster management. It will contribute to making accurate and fast decisions in urban planning. In addition, it will also be able to use as a tool for risk management in emergencies.
- MakaleAçık Erişim2023Energy and economic assessments of waste heat recovery by designs of economizer, condensing economizer and air preheater; [Ekonomizer, yoğuşmalı ekonomizer ve hava ön ısıtıcı tasarımları ile atık ısı geri kazanımının enerji ve ekonomik değerlendirilmesi]
Terhan, Meryem; Özağdaş, Emre; Omar, Muhammed Arslan
In this study, the waste heat loss of flue gases from the boilers of Kafkas University district heating system has been calculated between 6-8% according to the combustion analysis and the annual cost of this heat loss has been found as $58,658.79. In terms of energy efficiency and the national economy, we think that this lost energy should be recovered as much as possible and fuel and energy savings should be achieved. In the paper, the effects of variants such as air excess coefficient, flue gas temperature, boiler capacity and fuel consumption on the heat recovery from flue gas have been presented in detail. The heat recovery scenarios have been presented for reusing this waste energy for space heating, domestic hot water, and preheating combustion air and the applicability of these scenarios has been investigated in terms of thermodynamics and economics. According to the results of the study, in the second scenario examined to cover the domestic hot water need of the guest house building, the energy savings of the scenario can be provided during 20 years of economic life is $122,820.83, and it has the highest savings income among the scenarios. In addition, it is possible to recover approximately 50% of the flue gas loss with thanks to the scenario. On the other hand, the third scenario of heating the boiler combustion air with waste heat is the easiest and most economical scenario because its payback period is only one year, and there are no extra excavation and pipe costs.
- MakaleAçık Erişim2022Investigation of environmental and time depended effects on historical masonry minarets by vibration test; [Tarihi yiǧma minarelerde çevresel ve zamana baǧli etkilerin titresim testi yardimiyla incelenmesi]
Yanik, Yusuf; Türker, Temel; Çalik, Ismet; Yildirim, Ömer
Historical structures are important pieces that connect past to present. Historical structures damaged for various reasons should be restored, repaired and strengthened. After these processes, the behavior of historical structures affected by environmental and time-dependent effects should be followed. For this purpose, current structural behavior of historical structures should be determined. Methods based on the dynamic characteristics of structure are very effective in the evaluation of structural behavior. In this study, dynamic characteristics of Tabakhane and Haci Kasim Muhittin Mosque Minarets in Trabzon province with different environmental conditions and different time intervals were experimentally obtained and compared. Experimental measurements of these minarets were carried out under environmental vibrations with Civil Engineering Vibration System (CEVS), which was developed by our research team, which can receive wired and wireless data. In Tabakhane Mosque Minaret, two measurements taken at different times before restoration and two measurements taken at different times after restoration were evaluated and compared each other. Measurement results of Haci Kasim Muhittin Cami Minaret before and after restoration and two measurements results taken at different times long after restoration were evaluated. The measurement data were analyzed separately in Civil Engineering Vibration Analysis (CEVA) program developed by our research team and in ARTEMIS program. In addition, dynamic characteristics obtained as a result of signal processing for both minarets were compared with previous studies. The reasons for differences in these values were examined depending on environmental condition and time.
- MakaleAçık Erişim2022Homotopy Perturbation Elzaki Transform Method for Obtaining the Approximate Solutions of the Random Partial Differential Equations
Anac, Halil; Merdan, Mehmet; Kesemen, Tulay
The series solutions of the random nonlinear partial differential equations have been examined by a hybrid method. The random nonlinear partial differential equations are studied by both normal and uniform distributions. Two initial-value problems are indicated to exemplify the influence of the solutions acquired by the hybrid method. Also, the functions for the first and second moments of the approximate solutions of random nonlinear partial differential equations are acquired in the MAPLE software. The hybrid method is implemented to analyze the solutions of the random nonlinear partial differential equations. MAPLE software is used to find the solutions. Besides, MAPLE software is used for the drawing the figures.
- MakaleAçık Erişim2022Investigation of biodegradability of doped composite oxide coated AZ91 alloy in blood plasma; [Katkili oksit kaplamasi büyütülen AZ91 alaşiminin kan plazmasi içerisindeki biyoçözünürlüǧünün incelenmesi]
Şüküroǧlu, Ebru Emine; Çelik, Ayşenur
Magnesium alloys; It is widely used in metallic biomaterials with its low toxic effect and biodegradability. Although these alloys help the formation of new tissues in the body, they provide great advantages over other metallic biomaterials due to their ability to dissolve from the body after the area of use has healed. However, due to their low corrosion resistance, they cause it to dissolve in the body before the treatment process is completed. This is the major disadvantage that limits the use of magnesium alloys. Various surface modification methods are applied to magnesium alloys in order to eliminate this disadvantage. Micro Arc Oxidation (MAO) method, which can provide a coating resistant to wear and corrosion, is one of the surface modification methods applied to improve the surface properties of magnesium alloys. In this study; Composite oxide coatings with Ag nanoparticle and Hydroxyapatite were grown by MAO method. Morphological properties of the coatings were determined by Scanning electron microscope and X-Ray Diffraction instruments. The antibacterial properties of Ag nanoparticle and HA doped composite oxide layer which were grown by MAO method and the biodegradability of the coated/uncoated materials in the blood plasma were investigated. As a result of the experiments, the development of bacterial activity in the sample coated by MAO was prevented by adding Ag nanoparticle and Hydroxyapatite to the electrolite solution. In addition, the biodegradation rate has been reduced by surface treatment on AZ91 Mg Alloy. As a result of the soaking test in blood plasma, it was determined that AZ91 Mg alloy protects itself against dissolution with a rate of approximately 89%.
- MakaleAçık Erişim2021Finding the optimum parameter values of the round robin CPU scheduling algorithm with genetic algorithm; [Döner çekirdek CPU tarifeleme algoritmasinin optimum parametre deǧerlerinin genetik algoritma ile bulunmasi]
Ökdem, Selçuk; Koşmaz, Betül
With the use of computers in every field, the usage intensity of processors is increasing day by day. In order to cope with this intensity, processors need to be constantly updated and improved. Various scheduling algorithms are being developed every day in order to continuously improve and accelerate the processors and to cope with the processing intensity. The main purpose of the scheduling algorithms is to increase the efficiency of the processor. For this, the processor needs to make a planning between the pending processes. Planning can be done by giving different priorities or using different methods. In order to increase the efficiency of the processor, in this paper, existing algorithms were examined. Round Robin Algorithm was improved using Genetic Algorithm. It is aimed to find the optimum values by selecting the quantum value according to the pending processes and their parameters. When the developed new method compared with the existing standard algorithms, it is observed that the waiting time and the turnaround time were shorter than the other algorithms.
- MakaleAçık Erişim2021Predicting stock prices using machine learning methods and deep learning algorithms: The sample of the istanbul stock exchange
Demirel, Ugur; Cam, Handan; Unlu, Ramazan
Stock market prediction in financial and commodity markets is a major challenge for speculators, investors, and companies but also profitable with an accurate prediction. Thus, obtaining accurate prediction results becomes extremely important especially while the stock market is essentially volatile, nonlinear, complicated, adaptive, nonparametric and unpredictable in nature. This study aims to forecast the opening and closing stock prices of 42 firms listed in Istanbul Stock Exchange National 100 Index (ISE-100) using well-known machine learning methods, Multilayer Perceptrons (MLP) and Support Vector Machines (SVM) models and deep learning algorithm, Long Short Term Memory (LSTM) by comparing their forecasting performances. The analysis includes 9 years of data from 01.01.2010 to 01.01.2019. For each firm 2249 data for the opening and 2249 for the closing stock prices were established as daily data sets. Forecasting performance of these methods was evaluated by applying different criteria for each model: root mean squared error (RMSE), mean squared error (MSE) and R-squared (R2). The results of this study show that MLP and LSTM models become advantageous in estimating the opening and closing stock prices comparing to SVM model.
- MakaleYalnız künye2017An integrated intuitionistic fuzzy set and mathematical programming approach for an occupational health and safety policy
Efe, Burak; Kurt, Mustafa; Efe, Ömer Faruk
This paper aims to establish an occupational health and safety policy for three firms. This paper provides to overcome the drawbacks of traditional FMEA (failure mode and effects analysis) by using an integrated intuitionistic fuzzy multi-criteria decision making method and a linear programming. Priority value of criteria has been defined by utilizing intuitionistic fuzzy analytic hierarchy process method and the highest risky failure mode among failure modes has been found by utilizing intuitionistic fuzzy VIKOR (VIsekriterijumska optimizacija i KOm-promisno Resenje). The application of risk evaluation is conducted to show the effectiveness of the proposed method in three firms. The reliability of the risk ranking is verified by helping of a sensitivity analysis and the advantages of the proposed approach are shown by comparing with the other methods. The managers of the firm present some limitations for the occupational health and safety policy so that these constraints are solved by helping of a linear programming. The results show that destroying of the existing steel ropes during production of plaster, risks that caused from work equipment and electric shock during cutting were determined the highest risky failure modes for construction, textile and metal firms, respectively.
- MakaleYalnız künye2011The effect of antifreeze admixtures on compressive strength of concretes subjected to frost action
Arslan, Metin; Çullu, Mustafa; Durmuş, Gökhan
This study aims to determine the effect of antifreeze admixture used in the concretes subjected to frost action on the concrete compressive strength. Three groups of concrete samples of C30 class were prepared with antifreeze admixtures by using the mixture of 30% calcium nitrate and 5% hydroxy ethoxy amin (A), calcium nitrate (B), Polyhydroxy amine (C). Concrete samples are put in the freezer in a fresh state 15 min after the mixing. Samples are subjected to frost action in 0, -5, -10, -15 and -20°C degrees for 48 hours. On the concrete samples water cured after 48 hours, compressive strength tests of 28 day are conducted. Consequently, it is seen that with the increase of the set temperature that concrete is cured, compressive strength of concrete is decreased and among all types of antifreezes the maximum decrease is seen between 0 and -5°C while the decrease in compressive strength is relatively less for -10, -15 and -20°C.
- DergiGazi University Journal of Science
- DergiJournal of the Faculty of Engineering and Architecture of Gazi University