Papers by ali ozhan akyuz
Nucleation and Atmospheric Aerosols, 2019
In sustainability practices, transportation systems make significant contributions to sustainable... more In sustainability practices, transportation systems make significant contributions to sustainable growth. Within the transportation systems, the aviation sector has a different position in terms of creating various service areas and the integrity of other transportation systems. It is aimed to reduce the noise level and harmful gas emissions by 80% in the aviation sector in the next 30 years. Despite the developments and studies in the field of sustainability, fossil fuel use is increasing and CO2 emissions in aviation cannot be reduced to the expected level. Isparta Suleyman Demirel Airport is an airport with a capacity of 1500000 passengers / year with 5400 m2 domestic and international lines, which was put into service in 1997. In this study, CO2 emission has been estimated by using Tier approach in 2018 according to flight type and number. It is aimed to provide a common framework for the determination and reduction of CO2 emissions in airport operations.In sustainability practices, transportation systems make significant contributions to sustainable growth. Within the transportation systems, the aviation sector has a different position in terms of creating various service areas and the integrity of other transportation systems. It is aimed to reduce the noise level and harmful gas emissions by 80% in the aviation sector in the next 30 years. Despite the developments and studies in the field of sustainability, fossil fuel use is increasing and CO2 emissions in aviation cannot be reduced to the expected level. Isparta Suleyman Demirel Airport is an airport with a capacity of 1500000 passengers / year with 5400 m2 domestic and international lines, which was put into service in 1997. In this study, CO2 emission has been estimated by using Tier approach in 2018 according to flight type and number. It is aimed to provide a common framework for the determination and reduction of CO2 emissions in airport operations.
Niğde Ömer Halisdemir Üniversitesi mühendislik bilimleri dergisi, Jul 31, 2019
Thermal science and engineering progress, Aug 1, 2023
This study deals with energy and exergy analysis of the experimental solarassisted Rankine cycle ... more This study deals with energy and exergy analysis of the experimental solarassisted Rankine cycle working with an environmentally friendly working fluid transcritical CO 2. The experimental system consists of evacuated solar collectors, a heat recovery system, condenser, a pump, and an expansion valve to simulate the realistic turbine operation. The system was designed for electricity production and the heat supply for various applications. The experiments were made funder typical winter and summer days to evaluate seasonal system performance in Kyoto, Japan. According to the obtained results, the turbine capacity was calculated as 0.118 kW and 0.177 kW for winter and summer seasons. From the exergetic point of view, solar collectors were found to be the major contributor to the total exergy destruction with 96.32% for summer and 93.58% for the winter season. Therefore, the efforts should be focused on the collectors. Thus, any attempt for improving the system performance should be focused on solar collectors first. Furthermore, the exergetic efficiency of the overall system was calculated as 7.63% for the winter season and 4.08% for the summer season. As a result, the utilization of CO 2 in the energy conversion cycle can be sustainably developed and extended by providing a glimpse into the carbon-free clean energy future.
Sustainable Energy Technologies and Assessments, Jun 1, 2023
Sustainable Energy Technologies and Assessments, Feb 1, 2023
Performances of smartphones are profoundly affected by battery life. Maximizing the amount of usa... more Performances of smartphones are profoundly affected by battery life. Maximizing the amount of usage of energy is essential to extend battery life. However, developers might concentrate more on the functionality of applications while ignoring the energy bugs that drain the battery during the development process. There are no quantitative approaches to detect these energy bugs introduced in this fast-paced development process. In this paper, we employ a system-call based approach to develop a power consumption model for Android devices. Data that measures the energy consumption of mobile devices under different testing scenarios with the number of triggered system calls are utilized in the model training process. A balanced recursive feature elimination with cross-validation approach is proposed to select and rank the importance of the different system calls. Seven machine learning models are trained over the selected features with cross-validation and hyper-parameter tuning technique, where linear regression with Lasso regularization outperforms all the other models. Then the model is evaluated on the data set that measures the energy consumption on different revision history of selected apps. Results show that the optimized Lasso model could detect energy bugs in the revision history of various applications. Optimization strategies are provided based on the selected features.
Teknik Bilimler Dergisi
GWP oranı düşük soğutucu akışkanlar soğutma sistemlerinin karbon ayak izinin azaltılması için öne... more GWP oranı düşük soğutucu akışkanlar soğutma sistemlerinin karbon ayak izinin azaltılması için önemlidir. Bu çalışmada bir soğutma sisteminde R404A ve alternatifi olnan R454C soğutucu akışkanlarının enerji ve çevresel analizi yapılmıştır. Analizler 5 farklı evaporatör sıcaklığı (-15 oC ile +5 oC) ve bir kondenser sıcaklığı (35 oC) için yapılmıştır. R454C’nin COP değeri R404A’dan yaklaşık olarak %4.0 oranında daha yüksektir. R454C’nin LCCP değeri R404A’dan biraz düşüktür (yaklaşık %3.5). Soğutma sistemlerinin karbon ayak izinin azaltılmasında soğutucu akışkanların GWP oranının düşük olması tek başına çözüm değildir. Soğutma sistemlerinin toplam karbon ayak izinin azaltılması için soğutma sistemi veriminin arttırılması ve çevre dostu enerji kaynaklarının (rüzgar, güneş, jeotermal enerji kaynakları vd.) kullanılması gerekir.
Pratik anlamda yenilenebilir enerji kaynaklarından faydalanmanın en uygun yollarından birisi olan... more Pratik anlamda yenilenebilir enerji kaynaklarından faydalanmanın en uygun yollarından birisi olan biyogaz üretimi ile yeşil enerjiye ulaşıldığı gibi geri dönüşümde sağlanarak çevreye fayda sağlanabilir. Biyogaz, yenilenebilir enerji kaynaklarının en umut verici kaynaklarından biridir ve coğrafi konumu nedeniyle Türkiye'de önemli bir potansiyele sahiptir. Bu çalışmada Burdur için farklı hayvan türlerine ve sayılarına bağlı olarak 2019 yılı için atık, biyogaz üretimi ve elektrik enerjisi eşdeğeri hesaplanmıştır. Hesaplama sonucunda Burdur için yıllık ortalama hayvansal atık içeren biyogaz üretimi 79249.97 m 3-CH4/yıl ve enerji değeri 2853 GJ/yıl olarak bulunmuştur. Ayrıca bu çalışmada biyogaz kullanılması halinde elektrik enerjisi üretiminin 277.37 MWhe/yıl olduğu ve bu sayede yılda yaklaşık 160.877 ton CO2 emisyonunun önlenebileceği belirtilmiştir.
Sterilizasyon bir malzeme veya ortamdaki virus, bakteri gibi tum mikroorganizmalarin yok edilmesi... more Sterilizasyon bir malzeme veya ortamdaki virus, bakteri gibi tum mikroorganizmalarin yok edilmesidir. Sterilizasyon genellikle fiziksel veya kimyasal yontemlerle yapilabilmektedir. Ultraviyole isinlari elektromanyetik spektrumun 100-400 nm arasindaki bolgede yer almaktadir. Ultraviyole isinlar genel olarak canlilar icin zararlidir ve bu isinlarin bir kismi atmosferde tutulur. Ultraviyole isinlari ile de yapilabilen sterilizasyon saglik sektorunde sicakliga ve neme dayanaksiz malzemelerin, tibbi operasyon yapilan ortamlarin ve suyun sterilizasyonunda uzun suredir kullanilmaktadir. Bu calismada universitelerin biyomedikal ile ilgili bolumlerinde uygulamali egitimde kullanilmak uzere bir ultraviyole sterilizasyon kabini tasarlanmistir. Tasarimda mikro denetleyiciler ile kontrol saglanmakta ve sensorlerle sterilizasyon ortaminin anlik sicaklik, nem, isik siddeti olcumleri gerceklestirilmektedir. Gelistirilen unite ile ilgili bolumlerin sterilizasyon cihazlari derslerinde ultraviyole isi...
International Journal of Energy Applications and Technologies, 2020
Nanotechnology is extremely important for efficient use, storage and production of energy. In thi... more Nanotechnology is extremely important for efficient use, storage and production of energy. In this context, it is one of the main objectives to contribute to cleaner, sustainable, production by reducing energy use with raw materials. Thus, it is ensured to prevent waste from various sources and to develop environmentally friendly production systems that produce less waste. Nanotechnology in the field of renewable energy sources, which is thought to be a solution to global warming that disrupts the natural balance, is one of the popular topics of today's technology. In this study, information is given about the usage areas of nanotechnology and its applications in the field of energy.
In the automotive laboratory, different engine types are studied. During the operation of the eng... more In the automotive laboratory, different engine types are studied. During the operation of the engines, trainers and students in the laboratory are exposed to many harmful effects. One of the most important of these effects is noise pollution. Noise pollution has many effects on human health. Moreover, in accordance with regulations, noise values should not exceed a certain level in working environments. The fact that the noise is above certain values requires the use of personal protective equipment. In this study, noise values were determined in different models of different engines in automotive laboratories. The design of the laboratory is designed to create a minimum noise value
Gasification is one of the major waste to energy technologies for renewable energy production. Ag... more Gasification is one of the major waste to energy technologies for renewable energy production. Agricultural residues have high potential to be used as significant source of renewable energy in Turkey. In this study, different gasification systems are compared to estimate the bioenergy potential of agricultural residues in Burdur province. Syngas produced from gasification process can be used as renewable fuel in internal combustion engines, turbines and boilers. Syngas energy potential of agricultural residues from air gasification of agricultural residues are evaluated in up-draft fixed bed, down-draft fixed bed and circulating fluidized bed systems. The results revealed that down-draft gasifier has shown the highest annual energy production potential of 402 MW in Burdur province.
Mesleki Bilimler Dergisi (MBD), Aug 1, 2018
Dünya enerji politikalarının eğilimini genel olarak doğalgaz ve petrol belirlemektedir. Bu çalışm... more Dünya enerji politikalarının eğilimini genel olarak doğalgaz ve petrol belirlemektedir. Bu çalışmada, küresel enerji politikalarına, stratejilerine ve sorunlarına yer verilmiştir. Türkiye'nin enerji güvenliği, petrol taşımacılığı gibi konulardaki önemine değinilmiştir. Gelişmiş ülkelerin, bazı ülkelerde bulunan enerji rezervlerindeki egemenliklerini koruma amacıyla yaptırımlar uyguladığı belirtilmiş ve incelenmiştir. Günümüzde enerji politikalarını belirleyen unsurlar ele alınmıştır. Ayrıca, nükleer enerjinin payı ve meydana getirdiği sorunlara vurgu yapılmıştır. Yenilenebilir enerjide artış gözlemlendiği ve gelecek yıllarda enerji yoksunluğunun yenilenebilir enerji ile en aza indirilebileceği çıkarımında bulunulmuştur. Yenilenebilir enerji talepleri, yatırımları ve gelişmeleri sayısal verilerle analiz edilmiştir. Küresel enerji politikalarındaki değişken unsurların önemi belirtilmiş ve yenilenebilir enerji kaynaklarının daha fazla ön planda olması gerektiği açıklanmıştır.
Mesleki Bilimler Dergisi (MBD), Aug 1, 2018
Dunya enerji politikalarinin egilimini genel olarak dogalgaz ve petrol belirlemektedir. Bu calism... more Dunya enerji politikalarinin egilimini genel olarak dogalgaz ve petrol belirlemektedir. Bu calismada, kuresel enerji politikalarina, stratejilerine ve sorunlarina yer verilmistir. Turkiye’nin enerji guvenligi, petrol tasimaciligi gibi konulardaki onemine deginilmistir. Gelismis ulkelerin, bazi ulkelerde bulunan enerji rezervlerindeki egemenliklerini koruma amaciyla yaptirimlar uyguladigi belirtilmis ve incelenmistir. Gunumuzde enerji politikalarini belirleyen unsurlar ele alinmistir. Ayrica, nukleer enerjinin payi ve meydana getirdigi sorunlara vurgu yapilmistir. Yenilenebilir enerjide artis gozlemlendigi ve gelecek yillarda enerji yoksunlugunun yenilenebilir enerji ile en aza indirilebilecegi cikariminda bulunulmustur. Yenilenebilir enerji talepleri, yatirimlari ve gelismeleri sayisal verilerle analiz edilmistir. Kuresel enerji politikalarindaki degisken unsurlarin onemi belirtilmis ve yenilenebilir enerji kaynaklarinin daha fazla on planda olmasi gerektigi aciklanmistir.
Arabian Journal of Geosciences, Jul 1, 2020
Plasma applications are widely used in a wide variety of processes in materials science and techn... more Plasma applications are widely used in a wide variety of processes in materials science and technologies. Gas-phase plasma and solid-phase plasma are useful and are developed for many technologies, such as coating, production of electronic devices, surface treatment, and nanomaterial synthesis. On the other hand, the solution plasma technique is a kind of electrohydrodynamic discharge technique and has recently been studied for potential applications in plasma physics. In this study, gold nanoparticle synthesis was performed by solution plasma technique. Electrohydrodynamic discharge was created with a bipolar DC power source (15 kHz-1.6 kV-2 μs) in a 0.86-mM aqueous chloroauric acid solution. The characteristic of the plasma formed was performed by optical emission spectrometry, and the characteristics of the aliquots taken from the reaction environment at specific time intervals were also performed by UV, XRD, and FESEM analysis. As a result, gold nanoparticles were obtained with atomic sizes ranged from 30 to 50 nm.
Bitlis Eren üniversitesi fen bilimleri dergisi, Mar 22, 2023
Increasing energy need poses various problems in terms of energy supply security and environmenta... more Increasing energy need poses various problems in terms of energy supply security and environmental aspects for many countries. Therefore, energy policies are an important part of sustainable development plans, especially in developing countries. Türkiye is one of the developing countries and its need for energy is increasing day by day. In Türkiye, which generally meets its energy needs from fossil fuels, it is very important both economically and environmentally to reduce the use of these fuels, which are harmful to the environment and depend on foreign sources, and to use renewable energy sources. Considering Türkiye's potential in renewable energy resources, the energy production efficiency to be obtained from the investments to be made is quite high. In this study, a numerical map was created by determining the biogas and energy potentials that can be obtained depending on the agricultural and animal wastes of the province of Isparta, Türkiye. In determining the energy potential, 2018 agricultural and animal statistics of the Turkish Statistical Institute were used. In the calculation made for the province of Isparta, a total of 25831264.2 m 3 /year of biogas can be obtained from animal wastes and the thermal value of this value is 586369.70 GJ/year and the total energy potential that can be obtained from some agricultural wastes is calculated as 3549790.42 GJ/year.
El-cezeri, May 31, 2020
Hydrostatic journal bearings are recommended for supporting shafts operating at high speeds and u... more Hydrostatic journal bearings are recommended for supporting shafts operating at high speeds and under heavy loads in the industry. In the journal bearings, lubricant viscosity decreases with increasing temperature at high rotation speeds and hence, the fluid between the surfaces should be circulated using a pump to cool the lubricant. However, the lubricant supplying between the surfaces at the high flow rate causes the whirl instability and vibrations problems in the bearing-shaft system. These instability problems give rise to significant damage on the system during operating at the high speeds and under heavy loads. As a solution to this problem, it could be suggested to control the variation of the lubricant viscosity concerning the temperature by adding nanoparticle. In the present work, the effects of the lubricant with nanoparticle additives on the load carrying capacity of a hydrostatic journal bearing are theoretically investigated. The fluid film flow between the bearing and rotor surfaces are modelled with Reynolds equation and the viscosity term in Reynold's equation is defined as a function which depends on the nanoparticle properties. Then, the pressure distribution is obtained with solving the film flow equation and the load capacity is calculated for different nanoparticle parameters using this pressure distribution. The results show that the usage of the lubricant with nanoparticle increases the load performance of the hydrostatic journal bearing and the influences of the nanoparticle size on the load performance is more dominant for high volumetric ratio.
El-cezeri, May 31, 2019
Gasification is a promising clean energy technology for hydrogen production and sustainable waste... more Gasification is a promising clean energy technology for hydrogen production and sustainable waste management. Biomass residues have great potential to produce renewable hydrogen. In this study, the potential of production of hydrogen from pepper residues was determined via a modeling study of air/steam gasification system. The input carbon of the feedstock was assumed to be fully gasified in the numerical model calculations performed for the downdraft gasifier system. Air to fuel ratio (A/F) and steam to fuel (S/F) ratio are taken as 0.05 because of the high oxygen content in pepper waste. The temperature of the gasifier is 877 °C for the developed mathematical model. The modeling study results revealed high hydrogen content in the producer gas derived from pepper waste gasification which has obtained as 49.08 %.
Nucleation and Atmospheric Aerosols, 2019
Acta Physica Polonica A, Mar 1, 2017
The solution plasma technique, which has been recently invented by Takai and Saito, produces radi... more The solution plasma technique, which has been recently invented by Takai and Saito, produces radicals, ions, UV photons, shock waves and metastable excited atoms. These generated active species are used as the source of some chemical reactions. The exact structure of the solution plasma is not well known at present, however it has been shown to be a versatile phenomenon for production of nanomaterials, sterilization and organic compound decomposition. Solution plasma technique has emerged as a great prospect for the chain scission (degradation) of polymers, to improve their solubility and physicochemical characteristics due to such advantages as absence of toxic materials, low temperature and usage of economical, simple equipment. In this study, polyvinylpyrrolidone, uncharged water soluble polymer of a known initial molecular weight, was continuously monitored using the continuous viscometry method, which gives the viscosity at any moment of the reaction, during the interaction of polyvinylpyrrolidone with plasma, for the first time in the literature.
Uploads
Papers by ali ozhan akyuz