Sürdürülebilir Kalkınma Amaçları

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• MakaleAçık Erişim2025/r/gumushane/12457
  Changes 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%.

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• MakaleAçık Erişim2024/r/gumushane/12569
  Effect 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.

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• MakaleAçık Erişim2024/r/gumushane/11400
  Design 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.

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• MakaleAçık Erişim2023/r/gumushane/12792
  Geographic 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.

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• MakaleAçık Erişim2023/r/gumushane/11557
  Energy 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.

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• MakaleAçık Erişim2022/r/gumushane/14769
  Investigation 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.

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• MakaleAçık Erişim2022/r/gumushane/12894
  Investigation 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%.

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• MakaleAçık Erişim2021/r/gumushane/14908
  Finding 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.

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• MakaleAçık Erişim2020/r/gumushane/14741
  A 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.

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• Derleme MakaleYalnız künye2019/r/gumushane/18049
  Nano materyal içerikli katkıların yakıt özelliklerine ve yanma karakteristiklerine etkileri

  Sezer, İsmet

  Bu çalışma; dizel, biyodizel, su içeren emülsiyon yakıtları ve çeşitli yakıt karışımları gibi dizel motoryakıtlarında nano materyal içerikli katkıların kullanımı üzerine yapılmış çeşitli çalışmaların sonuçlarındanderlenmiştir. Dizel motorlarda zararlı egzoz emisyonlarını azaltması için üç farklı teknik uygulanmaktadır.Zaralı emisyonları azaltmak için uygulanan tekniklerden ilki motor tasarımda ve yakıt püskürtme sistemindedeğişiklikler yapılarak yanmanın iyileştirilmesidir. Ancak bu pahalı ve zaman alıcı bir süreçtir. İkinci teknikkatalitik konvertör ve partikül filtresi gibi çeşitli egzoz gazı cihazlarını kullanmaktır. Ancak, bu cihazlar dizelmotorun performansını olumsuz yönde etkiler. Dizel motorlarda, emisyonları azaltmak ve aynı zamandadizel motorun performansını artırmak için kullanılan üçüncü teknik ise çeşitli yakıt katkılarınınkullanılmasıdır. Dizel motorlardan yayılan en önemli kirleticiler azot oksit (NOx) ve partikül madde (PMis) emisyonlarıdır. Uygulamada, NOx ve PM emisyonlarını birlikte azaltmak oldukça zordur. Emisyonlarıazaltmanın ve motor performansını artırmanın en iyi yolunun nano materyal içerikli katkıların ve suylaemülsiyonlaştırılmış yakıtların kullanımı olduğu birçok araştırmacı tarafından bildirilmektedir. Buderlemede çeşitli dizel motor yakıtlarında farklı nano materyal içerikli katkıların kullanımının yakıtözelliklerine ve yanma karakteristiklerine etkileri incelenmiştir.

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