WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7150

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Department: search.filters.department.İzmir Institute of Technology. Mechanical EngineeringScopus Q: search.filters.scopusQuartile.N/A

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Now showing 1 - 10 of 65
  • Data Paper
    Citation - WoS: 15
    Citation - Scopus: 20
    Database Covering the Prayer Movements Which Were Not Available Previously
    (Nature Publishing Group, 2023) Mihçin, Şenay; Şahin, Ahmet Mert; Yılmaz, Mehmet; Alpkaya, Alican Tuncay; Tuna, Merve; Akdeniz, Sevinç; Can, Nuray Korkmaz; Tosun, Aliye; Şahin, Serap
    Lower body implants are designed according to the boundary conditions of gait data and tested against. However, due to diversity in cultural backgrounds, religious rituals might cause different ranges of motion and different loading patterns. Especially in the Eastern part of the world, diverse Activities of Daily Living (ADL) consist of salat, yoga rituals, and different style sitting postures. A database covering these diverse activities of the Eastern world is non-existent. This study focuses on data collection protocol and the creation of an online database of previously excluded ADL activities, targeting 200 healthy subjects via Qualisys and IMU motion capture systems, and force plates, from West and Middle East Asian populations with a special focus on the lower body joints. The current version of the database covers 50 volunteers for 13 different activities. The tasks are defined and listed in a table to create a database to search based on age, gender, BMI, type of activity, and motion capture system. The collected data is to be used for designing implants to allow these sorts of activities to be performed.
  • Article
    Citation - WoS: 2
    The Effect of the Temperature of Heat Treatment Process and the Concentration and Duration of Acid Leaching on the Size and Crystallinity of Nano-Silica Powders Formed by the Dissociation of Natural Diatom Frustule
    (American Scientific Publishers, 2022) Ülker, Sevkan; Güden, Mustafa
    The present study focused on the processing of nano-silica powders in varying sizes and crystallinities through IP: 846247.10 On: Wed, 14 Dec 2022 07:29:25 heat treatment (900-1200 degrees C), hydrofluoric acid leaching (1-7 N), and ball milling (1 h, 500 rpm) of natural Copyright American Scentfic P blishers diatom frustules. The starting natural frustules were determined to be composed of amorphous silica (88%) Delivered by Ingenta and quartz. The partially ordered crystalline low-quartz and or precursor to low-cristobalite started to form at-900 degrees C. As the heat treatment temperature increased, the crystallinity of the frustules increased from 9.3% at 25 degrees C to 46% at 1200 degrees C. Applying a ball milling reduced the mean particle sizes of the as-received and heat-treated frustules from 15.6-13.7 mu m to 7.2-6.7 mu m, respectively. Acid leaching of the as-received and heat-treated frustules resulted in a further increase in the crystallinity. Furthermore, a ball milling applied after an acid leaching was very effective in reducing the particle size of the as-received and heat-treated frustules. The mean particle size of the acid-leached frustules decreased to 774-547 nm with a crystallinity varying between 12 and 48% after ball milling. A partially dissolved amorphous phase was observed in between crystalline silica grains after acid leaching, which resulted in a rapid fracture/separation of the frustules in ball milling.
  • Article
    Citation - WoS: 8
    Citation - Scopus: 9
    Experimental Investigation of Air Cooling With/Out Tab Cooling in Cell and Module Levels for Thermal Uniformity in Battery Packs
    (ASME, 2023) Göçmen, Sinan; Çetkin, Erdal
    Catastrophic effects of global warming and environmental pollution are becoming more evident each day, and reduction in fossil fuel consumption is an urgent need. Thus, electric vehicles powered by sustainable energy sources are becoming a major interest. However, there are some challenges such as safety, limited range, long charging times, and battery life which are inhibitory to the adaptation of them. One of the biggest reasons for these challenges is the relationship between battery degradation and temperature which can be eliminated if batteries can be kept at the optimum temperature range. Here, the effects of three distinct (natural convection, forced convection, and tab cooling) methodology were experimentally compared at both the cell and module levels (six serial 7.5 Ah Kokam pouch cells, 1P6S) for thermal management of lithium-ion cells. The experiments were conducted at a discharge rate of 3C with ambient temperatures of 24 ◦C and 29 ◦C. The cell-level test results show that the tab cooling yields 32.5% better thermal uniformity in comparison to the other techniques. Furthermore, tab cooling yields better temperature uniformity with and without air convection as the hot spots occurring near the tabs is eliminated. For the module level, the forced air convection method stands out as the best option with a 4.3% temperature deviation between cells and maximum cell temperature of 39 ◦C. Overall, the results show that a hybrid approach with tab cooling would be beneficial in terms of temperature homogeneity especially in high capacity electric vehicle battery cells.
  • Conference Object
    Citation - WoS: 3
    Citation - Scopus: 3
    Experimental Evaluation of the Success of Peg-In Tasks Learned From Demonstration
    (IEEE, 2022) Argüz, Serdar Hakan; Ertuğrul, Şeniz; Altun, Kerem
    Industrial robots are traditionally programmed by hard-coding the desired motion into them. That approach, however, costs significant time and effort and shows little to no promise in transferring human skills to robots. Programming by demonstration (PbD) is an alternative approach that allows robots to learn tasks from demonstrations. Because of its several advantages over the traditional method, PbD is particularly suited for tasks encountered in assembly operations, the most typical of which is the peg-in-hole task. A successful PbD implementation for a peg-in-hole task requires that the peg should still be inserted into the hole even under situations that are not encountered during the demonstrations. Previous research in the field shows that the success rate of a peg-in-hole task under such cases varies greatly. In this study, we use a UR5 manipulator to experimentally investigate how the success rate of a peg-in-hole task changes with respect to the novelty of the task, quantified in terms of the distance of the hole to its original position. It is found that the success ratio decreases as the novelty of the task increases. To increase the performance, the use of strategies that alter the robot's motion dynamically in the run time is suggested for future work.
  • Conference Object
    Üst Ekstremite Hareket Kabiliyeti Değerlendirmesi için Yeni Bir Sistem Tasarımı
    (IEEE, 2020) Çizmecioğulları, Serkan; Mihçin, Şenay; Akan, Aydın; Koçak, Mertcan; Tosun, Aliye
    Üst ekstremite fonksiyon değerlendirilmesinde kullanılan yöntemlerden birisi de Eklem Hareket Açıklığı (EHA) ölçümleridir. Günümüzde bu ölçümler klinisyenin gözlemsel değerlendirmesine ve/veya gonyometrik ölçümlere dayanmaktadır. Bu ölçümlerde tekrarlanabilirlik ve güvenilirlik açısından problemler mevcuttur. Bu çalışmada üst ektremitede EHA ölçümlerinin sayısal değerlendirilmesine bağlı olarak objektif çıkarımlar yapılmasını sağlayabilecek tek kameralı bir sistem önerilmiştir. Bireylerin omuz ve dirsek fleksiyonu hareketleri kaydedilmiştir. Eş zamanlı olarak “Altın Standart” olarak OptiTrack sistemi ile de yapılan hareketler kayıt altına alınmıştır ve analiz edilmiştir. Çalışmaya 9 erkek ve 9 kadın birey katılmıştır. Hareketlerin kaydedilmesi için Kinect kamera kullanılmıştır. Kinect kamera OptiTrack sistemi ile karşılaştırılmıştır. Omuz ve dirsek fleksiyonu açıları her iki sistem ile hesaplanmıştır. Hesaplanan açılar kullanılarak her iki sistemin uyumu istatiksel olarak incelenmiştir. Bland- Altman yöntemi kullanılarak yapılan analizlerde hem erkek hem de kadın bireylerde omuz fleksiyonu ve dirsek fleksiyonu hareketleri açısından %95 güven aralığında her iki kameranın birbiriyle uyumlu olduğu tespit edilmiştir. Bu çalışma önerilen sistemin klinik tanı için güvenirliğine dair delil teşkil etmektedir.
  • Conference Object
    Citation - WoS: 1
    Citation - Scopus: 2
    Parametric Analysis for the Design of Hip Joint Replacement Simulators
    (IEEE, 2021) Torabnia, Shams; Mihçin, Şenay; Lazoğlu, İsmail
    The simulation of wear, between the components of artificial hip joint implants, is a complicated problem that does not have a robust analytical answer yet. Many studies have been conducted to predict the wear between the femur head and the acetabular cup, as the debris generated due to the wear might produce adverse effects after the surgery. Hip joint simulators provide a means to quantify the amount of wear in preclinical settings, as an in vitro method. However, this brings some other challenges in terms of bio-fidelity. The simulators use force and range of motion data as input and provide wear information as an output. For this reason, it is important to be able to simulate the realistic conditions, by the proper transmission of force and position controlling of the components. Many studies performed on wear simulators but none of them worked on the machine parameters such as power consumption and sensitivity to external inputs in detail. In this study, we perform a sensitivity analysis of the factors affecting the forces acting on the femur head. In silico simulations were performed by changing the values of acting force, friction coefficient, and radius of femur head to understand the effects of each parameter on the frictional moment of the joint. These analyses demonstrate the importance of using correct parameters while designing simulators, which accept flexible boundary conditions. The architecture of the hip simulator was also investigated for the first time. The results are expected to pave the way for improving the bio-fidelity of the simulators in the field of biomechanics. © 2021 IEEE.
  • Article
    Citation - WoS: 1
    Performance Analysis of Thermal Storage Assisted Cooling Tower With Night Cooling
    (Gazi Üniversitesi, 2020) Ouedraogo, Kiswendsida Elias; Toprak, Kasım
    As global warming and water scarcity issues continue to grow, it is essential to increase resources efficiency for air conditioners and power plants. In order to increase the efficiency, the systems need to be modified to take the advantages of the low night temperature and thermal storage tanks. In this study, the low night temperature and thermal storage tanks effects on the cooling tower is studied using TRNSYS. Using a chiller operating from 8:00 to 16:00 as a case study, hot water from the condenser is partially stored on daytime and cooled slowly during the night. The storage tank volume is optimized by considering two big tanks and five small tanks. The results show that night cooling reduces cooling water temperature by 5.8 degrees C or 21.8% while the cooling efficiency is increased by 36%. The thermal storage tanks enable to have the low continuous flow rate and help to reduce the fan power by 67.1%. On the storage side, compared to two tanks system, the tanks volume is reduced by 16.5% when 5 tanks are used. In theory this reduction can go up to 50% by increasing the number of tanks and reducing their individual size.
  • Conference Object
    Heat Load Factor for Geothermal District Heating System Design
    (National Technical University of Athens, 2006) Yıldırım, Nurdan; Gökçen, Gülden
    Design of heating systems using conventional fuels is based on peak load which is calculated according to the coldest outdoor design temperature. But in geothermal district heating system design it is common practice to use a heat load factor between 0.6-0.7 since the resource is continues, cheap and system can be run for 24 hours a day. Heat load factor can be defined as a ratio of actual heat load to design heat load of the system. In this study, a geothermal district heating system is designed for Izmir Institute of Technology Campus, Izmir, Turkey and simulated for a heat load factor range of 0.5-1. For the Campus case, the heat load factor is determined as 0.53-0.0.67 based on indoor air temperature and operational cost.
  • Conference Object
    Cash Flow Forecasting by Using Time Series Methods in Geothermal District Heating Systems: Balcova - Narlidere Case
    (National Technical University of Athens, 2006) Erdoğmuş, Abdullah Berkan; Özerdem, Barış
    Cash flow forecasting is one of the difficult and important tasks in an economic evaluation of a geothermal investment. Geothermal district heating systems are characterized by a high capital cost. In addition, relatively low operation and maintenance costs occur throughout their life. The aim of this research is to estimate the potential cash flows for Balcova - Narlidere Geothermal District Heating System by using historical data accumulated over a period of time and several forecasting methods: moving average, exponential smoothing, adjusted exponential smoothing and curve fitting functions. Mean absolute percentage deviation (MAPD) which is the most common approach to select the appropriate method to a particular time series is used in the selection of the most suitable model. Alternative methods are compared with each other regarding to their MAPD values. It is found that the models represented by exponential curve fitting functions have smaller MAPD values and give better results in cash flow forecasting of investment investigated.
  • Conference Object
    Tıbbi Uygulamalar için Özgün Yapılı Haptik Cihaz Tasarımı
    (Institute of Electrical and Electronics Engineers Inc., 2009) Selvi, Özgün; Bilgincan, Tunç; Kant, Yalkın; Dede, Mehmet İsmet Can
    Robotik sistemler hassasiyet gerektiren işlerde gün geçtilçe günlük hayatımızın bir parçası olmaya başladı. Bu işler genellikle herhangi bir operatör tarafından yapılamayacak kadar hassasiyet gerektiren işler olduğundan dolayı robotik teknolojiye ihtiyaç vardır. Bir robotik alanı olan Haptik teknolojisi, operatör ile çevrenin etkileşimini kuvvet geri beslemesi ile sağlayarak uygulamanın hassasiyet seviyesini arttırmaktadır. Bugünkü haliyle haptik teknoloji tıbbi operasyonlarda yardımcı sistem olarak ve birçok uzaktan kumandalı operasyonlarında (teleoperasyon) kullanılmaktadır. Aynı zamanda haptik teknoloji askeri ve tıbbi eğitim amaçlı sanal gerçeklik programlarında kullanılmaktadır. Bu çalışmanın amacı sistemin hassasiyetini arttırabilecek yapısal olarak yeni bir haptik cihaz tasarlamaktır. Bu kapsamda, önceden gerçekleştirilmiş robot tasarımları araştırıldı ve kavramsal tasarımlar gelistirildi. Sonuç olarak seçilen tasarım sanal ortam da oluşturuldu ve simülasyonu yapıldı, ve ilk prototipi imal edildi