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Multifunctional SnO2-@ doped glass fiber-reinforced concrete: improved microstructure, mechanical, dielectric, and energy storage characteristics
(Elsevier Ltd, 2025) Ramazanoğlu, Doğu; Subaşı, Azime; Musatat, Ahmad Badreddin; Demir, Ahmet; Subaşı, Serkan; Maraşlı, Muhammed
This study explores SnO₂-based hybrid composite (SnO₂-@) doped glass fiber-reinforced concrete (GFRC) for enhanced dielectric, energy storage, and mechanical performance. Microstructural analysis confirmed SnO₂-@ promotes ettringite and calcium silicate hydrate (C-S-H) formation, improving matrix integrity. Aged samples exhibited a 650 % increase in surface roughness (Ra) and over 200 % higher Leeb hardness, demonstrating durability. Dielectric spectroscopy revealed frequency-dependent tunability: 1 % SnO₂-@ achieved a peak dielectric constant (ε' = 130 at 10 kHz), shifting to ε' = 140 at 100 kHz for 2–3 % doping. AC conductivity surged by 60 %, correlating with SnO₂-@-induced interfacial polarization and charge mobility. Energy storage capacity improved significantly, attributed to optimized dipole alignment and reduced leakage currents. Color stability remained robust (ΔE* ≤ 2.8 post-aging), ensuring aesthetic viability. These results position SnO₂-@-doped GFRC as a multifunctional material for smart infrastructure, integrating structural resilience, adaptive dielectric properties, and energy storage potential for next-generation urban applications.
Experimental and optimization study of nanofluid utilized PVT systems with hydrocarbon based PCM: an energetic-exergetic approach
(Elsevier Ltd, 2025) Kurtoğlu Sontay, Kübra; Öğüt, Elif; Ustaoğlu, Abid; Özkan, Doğuş; Kurşuncu, Bilal
Cooling of photovoltaic thermal (PVT) systems is crucial for enhancing electrical efficiency by reducing the operating temperature of photovoltaic modules. Elevated temperatures negatively affect the performance of PV cells, leading to a decline in energy conversion efficiency. Photovoltaic thermal (PVT) systems, hybrid technologies that generate electricity and heat, are crucial for efficient energy conversion. This study uniquely explores the performance of a PVT system by integrating phase change materials (PCMs) and nanofluids in PVT systems combined with optimization analysis. By combining these advanced cooling methods, both electrical and thermal efficiencies are significantly optimized, demonstrating the potential for improved energy conversion in PVT systems. Within this scope, three identical systems–water-cooled, nanofluid-cooled, and a combination of nanofluid cooling with PCM- were analyzed regarding electrical, thermal, and exergy efficiencies. Identical panels were placed side by side and tested. Additionally, an optimization analysis has been conducted to enhance the performance of each panel by evaluating the thermal and electrical efficiency values obtained from experimental data based on system parameters and levels. In addition, thermogravimetric analysis and differential scanning calorimetry were conducted to determine the melting point of the Hydrocarbon-Based PCM. Compared with traditional methods, these analyses conducted in conjunction with the experimental study provide a more reliable basis for performance evaluation studies of PVT systems. The results of the experimental study showed that Nanofluid-Integrated PVT with Hydrocarbon-Based PCM achieved 11.7 %, 11.6 % and 10.6 % higher electrical efficiency, overall exergy and electrical exergy respectively, compared to the water-cooling method. Additionally, a 6.6-fold increase in thermal efficiency and a 4.4-fold increase in overall efficiency were observed. Similarly, compared to the nanofluid cooling method, this combination provided 4.9 %, 5.9-fold and 3.47 % improvements in the electrical, thermal and overall exergy efficiencies metrics. The results of the optimization analysis revealed that the combination of PCM and nanofluids ensures greater stability in electrical efficiency values under high-temperature differences. It was also observed that solar irradiance is the most influential parameter affecting efficiency. The obtained results demonstrate that the nanofluid-cooled system integrated with PCM has a significant impact on enhancing the performance of PVT systems. The combined use of nanofluid and PCM considerably improves all efficiency parameters.
The Role of RRA heat treatments on corrosion behaviour of AlSi10Mg produced by additive manufacturing
(Elsevier B.V., 2025) Özer, Gökhan; Tütük, İbrahim; Cingöz, Umut Can; Koç, Ebubekir; Karaaslan, Ahmet
In this study, AlSi10Mg samples were produced using the Powder Bed Laser Fusion (PBLF) method with standard parameters. Specimens were retrogression and re-aging (RRA) heat-treated at various conditions. The effects of the RRA heat treatments on the properties of PBLF parts were examined by microstructure, electrical conductivity, and electrochemical corrosion tests. Microstructural properties were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray (EDS) analysis. The results showed that after RRA heat treatment, the electrical conductivity of the material decreased slightly, and the corrosion resistance increased.
Analyzing traffic accident trends and correlations in Iraq: an investigative statistical approach
(American Institute of Physics, 2025) Hassooni, Dhuha Khalid; Ghasemlounia, Redvan; Hilal, Miami Mohammed; Al-Saffar, Zaid Hazim; Mohammed, Ghufran Taha
Traffic accidents are for two reasons, human-related and road-related structural behavior, two of which are in need of investigation. Herewith, this study embarks on an analysis of the dynamics of traffic accidents within Iraq, with a pronounced emphasis on statistical analyses concerning Baghdad, the capital city which is bearing the highest accident rates. An expansive dataset encompassing 10959 traffic incidents recorded over the year 2022 is utilized with this paper examining the distribution and nature of road accidents alongside the resultant degrees of injury. Through the deployment of Histograms and Q-Q Plots, the research confirms the normality of the data, paving the way for subsequent Pearson Correlation and ANOVA tests. These statistical methodologies reveal moderate, yet statistically insignificant, correlations between the nature of accidents and the characteristics of roads, with an F-statistic of 0.247 indicating no substantial effect of accident nature on the type of roads within Baghdad. Notably, the analysis extends to gender-referenced mortality records and root cause analyses that highlight significant seasonal fluctuations in accident occurrences, as well as pivotal gender disparities in road traffic incidents. The city-based accident records, detailed distributions of traffic accidents by nature, degree of injury, and recent accident trends, alongside statistical test visualizations, collectively underpin the analytical discourse. In conclusion, the paper asserts the critical necessity for targeted interventions and policy reforms aimed at mitigating these identified trends and contributing to the broader objective of enhancing road safety in Iraq.
Performance of ECC mortar containing limestone powder as a full replacement of fine aggregate
(American Institute of Physics, 2025) Mohammed, Ghufran Taha; Abed, Jasim Mohammed; Hassooni, Dhuha Khalid
Limestone powder (LP), derived from marble dust and stone waste, was utilized as a sand substitute in engineering cement compounds (ECC). This readily available material is a by-product of industrial waste from local quarries and stone cutting, and it was sourced from Mosul factories for this research. The study aimed to fully replace the fine aggregate in ECC with LP. Experimental findings demonstrated that LP had an impact on the hardening and drying process, resulting in longer drying and hardening times. Consequently, there was a decrease in the initial compressive and tensile strength. However, the use of finer LP compensated for this effect. Seven mixtures were tested with varying LP/PC (Portland Cement) replacement ratios (0.75, 1, 1.5, 2, 2.5, 3, and 3.5). The best results were obtained with mixture M5. The addition of LP led to an increase in compressive strength, with values reaching up to 32.40 MPa at 28 days. Finer LP particles further enhanced this effect. Conversely, increasing the LP/PC replacement ratio resulted in a reduction in tensile strength due to the higher water-cement ratio. The tempering effect contributed to an enhancement of 3.92 MPa in tensile strength. The incorporation of LP significantly reduced the environmental impact by decreasing the demand for natural resources. The use of limestone in the ECC mortar gave good results for tests of the mechanical properties of the mortar, as this is considered a viable option for use in building, construction, and repair operations. It is recommended that further improvements, research, and studies be conducted to improve the formulations and types of such alternative mortar.
Deep learning algorithm for dessert recognition and nutritional evaluation
(Food Reseach Institute, 2025) Yusun, Sevilay; Yılmaz, Onur; Tarlak, Fatih
Food recognition systems are crucial for healthcare and the food industry, aiding in diet tracking, personalised meal planning, and promoting nutritional awareness. This work develops a software interface that recognises food products using deep learning algorithms, and announces their nutritional values and gastronomic characteristics. Specifically, photographs of various desserts were captured in a restaurant setting, and the classification performance of two deep learning models, GoogleNet and ResNet-50, was analysed. Both models achieved high accuracy rates exceeding 99.6 %, with ResNet-50 demonstrating superior performance due to its lower error rates, higher accuracy, and faster learning capabilities. Based on these results, the interface was developed using ResNet-50 to provide consumers with detailed gastronomic information about desserts and support healthier dessert choices. At present, the resulting software is limited to the 23 dessert items on the menu of Healin restaurant (Nisantasi, Istanbul, Turkey), and the way they look in that particular restaurant, but the scope could be expanded in the future. This innovative approach enhances consumer awareness about healthy eating while offering a competitive edge for the food industry by effectively meeting consumer expectations.
Thermodynamics analyses of ionic GO plus MXene/EG plus water hybrid nanofluid in a circular tube including a novelty vortex generator
(Elsevier Science SA, 2025) Gürsoy, Emrehan; Gürdal, Mehmet; Yıldırım, Furkan
This research explores the thermo-hydraulic efficiency and entropy generation characteristics of an innovative hybrid nanofluid (GO+MXene/EG+water) flowing through a circular tube, enhanced by a novel vortex generator incorporating dimpled fins with spherical, elliptical, and trapeze geometries placed on wave tapes. The vortex generators effectively disrupted boundary layers, thereby improving thermal performance across all configurations. The novelty of this research lies in the first-time examination of MXene-based hybrid nanofluids in conjunction with vortex generators to assess thermo-hydraulic performance and entropy generation. Due to its excellent thermal conductivity and stability, the hybrid nanofluid was studied under laminar flow conditions, with Reynolds numbers ranging from 500 to 2000. The findings reveal that the GO+MXene/EG+water hybrid nanofluid enhances the convective heat transfer coefficient by 20.32% while increasing the pressure drop by 25.85% compared to the base fluid. Besides, GO+MXene/EG+water hybrid nanofluid reduced the thermal entropy generation at the rate of 60.6%. Among the studied fin geometries, spherical dimpled fins demonstrated the highest heat transfer improvement, with a normalized heat transfer ratio of 1.02, whereas trapeze fins exhibited relatively lower enhancement. This research contributes to the scientific community by providing valuable insights into the optimization of heat exchangers and other industrial thermal systems, facilitating enhanced heat transfer with reduced entropy generation. The study's findings have significant implications for future investigations on the integration of hybrid nanofluids and extended surface heat transfer enhancement techniques. Notably, the results offer a foundation for the development of novel designs that leverage hybrid nanofluids to improve energy efficiency in industrial systems.
Structural and electrical properties of CuO-doped NaNbO3 ceramics
(Walter de Gruyter GmbH, 2025) Berksoy Yavuz, Ayşe; Danışman, Murat
Ceramics are one of the key materials of today’s industry. The manufacturing technique used for preparing the ceramics greatly affects the material’s structural and electrical properties. Therefore, the elements and their distribution in the material as well as understanding their relation with the manufacturing process are the key factors for managing the expected outcome. In this study, NaNbO3 ceramics and the effect of CuO-doping in solid state calcination process was investigated. For this purpose pure, 0.5 mol.% and 1.0 mol.% CuO-doped sample discs were prepared. Crystallite size, strain, atomic structure, lattice parameters and atomic occupancies of the material were calculated by using X-ray diffraction patterns combined with Rietveld analysis. Additionally, the samples were investigated with the scanning electron microscopy technique to observe the effect of CuO doping. For electrical characterization, dielectric constant and tangent loss measurements were carried out on samples. As a result, it was concluded that CuO doping affected the crystal structure of the NaNbO3 which triggered the changes in its electrical behavior. The observed effects were more pronounced at 1.0 mol.% CuO content.
Non-invasive Raman and XRF study of Mīnā’ī decoration, the first sophisticated painted enamels
(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Colomban, Philippe; Şimşek Franci, Gülsu; Ngo, Anh-Tu; Gallet, Xavier
Mīnā’ī wares, crafted during the 12th–13th centuries, represent some of the earliest examples of sophisticated painted enamel decoration by potters. Due to the thinness of these enamel layers, their detailed characterization remains challenging, even with the use of advanced techniques, such as Proton-Induced X-ray Emission (PIXE) analysis and Rutherford Backscattering Spectrometry (RBS). This study provides the first combined non-invasive analysis, using X-ray fluorescence (XRF) and Raman spectroscopy, of five shards attributed to mīnā’ī wares. For comparison, two İznik shards from the 17th century, which feature similarly styled but thicker enamel decorations, were also analyzed. Interestingly, the mīnā’ī paste was found to contain lead and tin, suggesting the use of a lead-rich frit in its composition. This finding was confirmed through micro-destructive analysis, using Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM–EDS). Elements, such as rubidium (Rb), strontium (Sr), yttrium (Y), and zirconium (Zr), produced significant XRF signals and effectively distinguished mīnā’ī wares from İznik wares. A uniform tin-rich glaze, measuring 300–500 µm in thickness, was used as a base layer for the much thinner painted mīnā’ī enamels. The colored areas (blue, turquoise, red, green, black, white, eggplant) revealed the presence of various coloring agents and phases, such as spinels, chromite, and ions like Cu2+ and Co2+, as well as opacifiers like cassiterite and lead–calcium/potassium arsenates. Two distinct cobalt sources were identified: one associated with arsenic and the other with manganese and nickel. These cobalt sources are comparable to those used in İznik pottery. For the first time, boron was detected in the blue enamel of mīnā’ī wares.
Thermodynamics analyses of ionic GO+MXene/EG+water hybrid nanofluid in a circular tube including a novelty vortex generator
(Elsevier B.V., 2025) Gürsoy, Emrehan; Gürdal, Mehmet; Yıldırım, Furkan
This research explores the thermo-hydraulic efficiency and entropy generation characteristics of an innovative hybrid nanofluid (GO+MXene/EG+water) flowing through a circular tube, enhanced by a novel vortex generator incorporating dimpled fins with spherical, elliptical, and trapeze geometries placed on wave tapes. The vortex generators effectively disrupted boundary layers, thereby improving thermal performance across all configurations. The novelty of this research lies in the first-time examination of MXene-based hybrid nanofluids in conjunction with vortex generators to assess thermo-hydraulic performance and entropy generation. Due to its excellent thermal conductivity and stability, the hybrid nanofluid was studied under laminar flow conditions, with Reynolds numbers ranging from 500 to 2000. The findings reveal that the GO+MXene/EG+water hybrid nanofluid enhances the convective heat transfer coefficient by 20.32% while increasing the pressure drop by 25.85% compared to the base fluid. Besides, GO+MXene/EG+water hybrid nanofluid reduced the thermal entropy generation at the rate of 60.6%. Among the studied fin geometries, spherical dimpled fins demonstrated the highest heat transfer improvement, with a normalized heat transfer ratio of 1.02, whereas trapeze fins exhibited relatively lower enhancement. This research contributes to the scientific community by providing valuable insights into the optimization of heat exchangers and other industrial thermal systems, facilitating enhanced heat transfer with reduced entropy generation. The study's findings have significant implications for future investigations on the integration of hybrid nanofluids and extended surface heat transfer enhancement techniques. Notably, the results offer a foundation for the development of novel designs that leverage hybrid nanofluids to improve energy efficiency in industrial systems.
Kalın kesitli hadfield çeliklerine karbon ve molibden ilavesinin etkisinin incelenmesi
(Osman Sağdıç, 2023) Öztürk, Faruk; Gürol, Uğur; Uysal, Mehmet
Hadfield çelikleri madencilik endüstrisinde özellikle yüksek tokluk ve aşınma direnci gerektiren astar plakalarında, konik kırıcıların cevher ile temas eden ve cevheri öğüten kırıcı mantolarında, kırıcı çenelerinde ve iş makinalarının yürüyüş takımlarında yaygın bir şekilde kullanılmaktadır. Bu çeliklerde artan kalite gereksinimleri nedeniyle, daha yüksek tokluk ve aşınma özellikleri elde etmek için dökümhanelerin Ar-Ge departmanları tarafından alaşım geliştirme ve ısıl işlem optimizasyon çalışmaları önem kazanmaktadır. Bu çalışmada kalın kesitli Hadfield çeliklerinde karbon ve molibden ilavesinin mikro yapı ve mekanik özelliklere etkisi incelenmiştir. Döküm numunelerinin karakterizasyonu için mikro yapı incelemelerine ek olarak sertlik, çekme ve darbe çentik testleri uygulanmıştır. Elde edilen sonuçlar en yüksek çekme ve süneklik değerlerinin düşük karbon içeriğine sahip (1.09%C) molibdensiz analiz ile elde edilebileceğini göstermiştir. Ayrıca, daha yüksek akma mukavemetine sahip karbürsüz bir yapı eldesi için molibden ilavesi olması durumunda ise ısıl işlem sıcaklığının veya süresinin arttırılması gerektiğini ortaya koymuştur.
The experiment and simulation results of speed control of permanent magnet synchronous motor by using fuzzy controller
(Istanbul Gedik University, 2018) Teker, Aykut; Erfan Kuyumcu, Feriha
This paper is concerned with the topics on the speed control of Permanent Magnet Synchronous Motor (PMSM) with using Matlab/Simulink in real system. The speed control of motor model is done with Fuzzy Logic controller. The Simulation and experimental results of controller performances are compared with the speed graphs obtained.
Golden ratio discovered in nonlinear superconductor
(Istanbul Gedik University, 2018) Aslan Çataltepe, Özden; Güven Özdemir, Zeynep; Onbaşlı, Ülker
Mercury based high temperature superconductor as a nonlinear dynamical system constitutes a natural laboratory for searching quantum chaotic transitions. In our previous works, these chaotic transitions had been expressed in details and mathematically proved by determination of negative Schwarzian derivative. In this work, we have focused on the net effective mass of the quasi particles, m* at the vicinity of absolute zero temperature and the mass of the double helix quantum wave i.e. topological Segâh solitons. The net effective mass of the quasi particles as the function of the phase of the superconducting system had already been determined in our previous works by using an advanced differential method that is based on the magnetic data obtained by SQUID (Superconducting Quantum Interference Device) measurements. The mass of the double helix quantum wave, whose wave length coincides with ultraviolet region of the electromagnetic spectrum, muv, has also been calculated with the wave length of the solitons in relativistic manner. Since we have already proved the three dimensional resonance at low temperatures for the mercury cuprates, the determination of the ratio of these masses at the vicinity of absolute zero would be a promising method for searching the properties of resonance. Hence, we have determined the resonance state which appears as the golden ratio in muv/m* values for the distances x=0.23?m and x=2,361?m at absolute zero temperature for the optimally and over oxygen doped mercury cuprate superconducting nonlinear condensed matter system, respectively.
Influence of local soil conditions on the structural design and associated costs
(Istanbul Gedik University, 2018) İnce, Harun; Toy, Ebru; Tolon, Mert
It is known that earthquakes occur along the faults as a result of the tectonic plate movements [1]. The North Anatolian, Northeast Anatolian and East Anatolian Faults create three major fault lines in Turkey. In connection with these fault lines, there are various studies concentrated mostly on the seismicity and the topic of earthquake hazard has been examined by many researchers until today. According to the literature, to cope with earthquake related problems, an utmost attention should be given to the existing building stock and currently available design principles used for earthquake resistant structures in the country. In general, the damage to buildings stem from the lack of knowledge and experience in the field, lack of soil survey database, and structural irregularities in plan and elevation. According to building design codes, the seismic load acting on the structures depends on the seismic zone, the soil type, its period of vibration and the mass of the building [2]. In the present study, the main objective is to evaluate the influence of local site effects on the seismic response of buildings in terms of 2018 Turkish Seismic Design Code provisions and to analyze their impact on the cost of construction of buildings. In the study, a two-story reinforced concrete-framed building (residential house) is used as an example. Using the architectural layout of the building, the thickness of floor slabs and column size are determined. The construction cost is estimated roughly by considering unit costs method. The cost of the reinforced concrete structure is determined by considering 2017 unit price list, specified by the Ministry of Environment and Urbanization [3]. It’s quite clear that the cost of structure built on soil class ZD is more expensive than the cost of the one built on the soil class ZA. The cost difference is around 22,57% between soil classes ZA and ZD.
Key value stream approach for increasing the effectiveness of business processes
(Altinbas University, 2020) Birgün, Semra; Gülen, Kemal Güven
In today’s competitive environment, the firms must have a flexible structure in order to quickly respond to the changes in customer requirements and to offer quality products while keeping the costs at a minimum. To gain competitive advantage, firms need to adapt to lean production and continuous improvement processes. This paper introduces a methodology – developed using Axiomatic Design principles – as a way to achieve a systematic approach in improving the organizational performance. This methodology is also tested and validated via case study.
Plasma studies in TÜBİTAK national metrology institute
(Gebze Teknik University, 2021) Ahmedov, Hacı; Korutlu, Beste; Orhan, Recep; Okumuş, Esra; Demir, Arif
Over the past few decades, low-temperature plasma researches have gained momentum as they lie at the core of numerous applications in industry, environment and medicine. Recently, metrology community has also begun to take advantage of the unusual properties of plasma to develop new advanced measurement techniques and new measuring devices. In accordance with this purpose, in 2019, the Plasma Laboratory was installed in TÜBİTAK National Metrology Institute (UME) within the scope of infrastructure research and development program founded by Industry Ministry of Turkey for contributing to the ongoing worldwide research on plasma studies. In this work, the current advances in Plasma Laboratory of UME will be introduced. We present the installed experimental set-up for low-temperature and low-pressure gas discharge plasma. We present our preliminary measurement results in determining electron temperature by Langmuir probe and optical emission spectrometer.
Sanayi devrimi ile gelen değişim: iş bölümü ve yabancılaşma
(İktisadi Kalkınma ve Sosyal Araştırmalar Derneği, 2021) Berktaş, Sena; Oraklıbel, Renk Dimli
Sanayi devrimi temelde sanayileşme, üretimde farklılaşma ile bilinmektedir. Ancak, devrimle beraber üretimin, dolayısı ile çalışma yaşamının değişmesi yaşamın tamamını etkilemiştir. Bu incelemede devrimin getirdiği değişimlere sosyolojik, teknolojik ve ekonomik açıdan etkileri ile sanayi devriminin çalışma hayatındaki etkileri olmak üzere iki başlıkta yer verilmiştir. Öncesinde 1., 2., 3. ve 4. Sanayi devrimleri (Endüstri 4.0) anlatılmıştır. Sanayi devrimlerine oluşumundan günümüze dek geçirdiği dönemlere yer verilerek devrimden öncesi ve sonrası arasında daha iyi neden sonuç ilişkisi kurulabileceği düşünülmüştür. Devamında bu incelemenin odak noktası olan iş bölümü ve yabancılaşma konusu detaylandırılmıştır. Sanayi devrimi ile çalışma şekli değişmiş, fabrikalarda seri üretim bantlarında iş bölümü ile üretim yapılmaya başlanmıştır. Devrim öncesi ürettikleri ürünün tamamına hâkim olan çalışanlar, artık ürünün küçük bir parçasından sorumlu olarak seri üretim bantlarında aynı işi sürekli tekrarlamak durumunda kalmışlardır. Beraberinde önceden genellikle tarlalarda esnek zaman dilimlerinde çalışan işçiler sanayi devrimi ile büyük şehirlere göç etmiş, fabrikalarda belirlenen iş saatleri çerçevesinde çalışmak ve dinlenmek durumunda kalmışlardır. Böyle bir çalışma şeklinin insan doğasına aykırı olduğu pek çok düşünür tarafından dile getirilmiştir. Yaptığı işe yabancılaşan insanlar, zaman içerisinde kendilerine de yabancılaşmaya başlamıştır. Bu inceleme kapsamında iş bölümü çeşitli örneklerle detaylandırılmış, yabancılaşma olgusu önemli düşünürlerin görüşleriyle ele irdelenmiştir.
İstanbul metro istasyonlarında iş güvenlik uygulamaları
(Demiryolu Mühendisleri Derneği, 2018) Damat, Arif; Utlu, Zafer
Metropol kentlerde şehir içi yaşamın getirdiği kalabalık trafik sorununuda beraber getirmektedir. Trafikten kurtulmak, işe vaktinde ve konforlu gitmek isteyen insanlar şehir içi ulaşımda metro kullanmaktadır. İstanbul’da hergün 2 milyondan fazla insan metro yolculuğu yapmaktadır. Bu tercih edilme beraberinde iş kazalarını da getirebilmektedir. Düşme, çarpma, çarpışma, tren ile peron boşluğuna ayak sıkışması, yürüyen merdivene ayak sıkışması, vb. kazalar metro istasyonlarında yaşanmaktadır. Bu çalışma da metro istasyonlarında , istasyon girişlerinden, perona inip trene binene kadar alınan iş güvenlik uygulamalarından bahsedilmiştir. Havalandırma sistemi, yangın ihbar ve kontrol sistemleri, yangından korunma sistemleri, PESB/CESB (Platform ve Merkezi Acil Durdurma Butonu), PAKS (Peron Ayırıcı Kapı Sistemi), Drenaj sistemi, Acil durum eylem planı, acil çıkış kapıları ve uyarı levhaları bu uygulamalardan bazılarıdır. Alınan bütün önlemlere rağmen işletme esnasında farklı tehlikeli durumların ortaya çıktığı görülmüş ve işletmeci firmanın bu problemlerin giderilmesine karşı aldığı iş güvenlik uygulamaları anlatılmıştır. Bu riskler risk değerlendirme yöntemlerinden fine-kinney ve 5x5 matris yöntemleri ile değerlendirilmektedir. Değerlendirme sonucu fine-kinney metodunun 5x5 matris yöntemine göre daha hassas sonuçlar verdiği görülmüştür.
Hayvan gübresinden biyogaz üretim potansiyelinin belirlenmesi: Ankara, Gaziantep, Kars*
(TMMOB Makina Mühendisleri Odası, 2024) Canci Matur, Utku; Atasayın, Aytaç
Gelişen teknoloji ve artan nüfusa paralel olarak enerji talebi gün geçtikçe hızla artış göstermiştir. Enerji talebinin artışı bu alanda yapılan çalışmalara hız kazandırmıştır. Halihazırda emre amade kullanılan konvansiyonel enerji kaynakları tükenebilme riski ve olumsuz çevre etkileri nedeniyle kullanımına sınır getirilmek istenen enerji kaynakları durumuna gelmiştir. Yenilenebilir enerji kaynakları bu anlamda konvansiyonel enerji kaynaklarına alternatif oluşturmuşlardır. Tükenme riski olmayan çevre dostu yenilenebilir enerji kaynakları son dönemlerde sıklıkla çalışılan konulardandır. Yenilenebilir enerji kaynağı olarak biyokütlenin kullanılması tarım ve hayvancılık alanında gelişmeye sebep olmuştur. Yapılan tarım ve hayvancılıkta atık olarak görünen ürünler değerlendirilerek, geri kazanım sağlanmış olacaktır. Hayvan dışkısı doğada kaldığı sürece açığa çıkan metan gazı sera etkisi yaratarak küresel ısınmaya neden olur. Suya karıştıktan sonra insan sağlığına zararlı hale gelir. Bu nedenle elektrik ve ısı enerjisi elde ederek geri dönüşümlü olarak bertaraf edilmesi önem arz etmektedir. Yapılan bu çalışma kapsamında ülkemizin farklı bölgelerinde bulunan Ankara, Gaziantep ve Kars illerindeki hayvan dışkısının toplanabilirliği dikkate alınarak biyogazdan elde edilebilecek potansiyel elektrik enerjisi araştırılmıştır. Bu kapsamda, Ankara ilinden 375.497,55 Mega Watt Saat Elektrik /Yıl (MWhe/yıl), Gaziantep ilinden 115.452,27 MWhe/yıl, Kars ilinden de 198.691,4 MWhe/yıl elektrik enerjisinin biyogazdan elde edilebilme potansiyeline sahip oldukları belirlenmiştir.
Some curvature properties of generalized complex space forms
(Istanbul Gedik University, 2019) Mutlu, Pegah
The object of the present paper is to study generalized complex space forms satisfying curvature identities named Walker type identities. Also It is proved that the difference tensor R. ? – ?.R and the Tachibana tensor Q(S, ?) of any generalized complex space form M(f1, f2) of dimensional m ? 4 are linearly dependent at every point of M(f1, f2). Finally generalized complex space forms are studied under the condition R.R – Q(S,R) = L Q(g , ?).

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