Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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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 85
  • 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.
  • Conference Object
    A Parametric Numerical Analysis of Laminar Hydrogen Diffusion Flames
    (International Association for Hydrogen Energy, IAHE, 2022) Korucu, Ayşe; Benim, Ali Cemal
    Atmospheric, laminar, diffusion flames of hydrogen and air are numerically investigated. A detailed hydrogen combustion reaction scheme, in combination with the extended Zeldovich mechanism for the thermal nitrogen oxide formation are used. For comparison purposes, a global mechanism is also applied. The numerical procedure is first validated by comparisons with results of other authors. Subsequently, parametric studies are performed to find optimal solutions with respect to the related to the operation parameters of such flames to achieve minimum low nitrogen oxide emission levels. The question that are addressed include the Reynolds number effect on nitrogen emissions, and the interaction of neighbouring flames, when they are applied in an array. For ensuring an adequately fine resolution of the flame fronts, local adaptive grid refinement techniques are applied to track the flame front. For preliminary results the radiative heat loses has assumed to be insignificant however it should be taken into the account for the further analyses. The maximum temperature is predicted to be ~2040 K which is higher than the reported adiabatic stoichiometric flame temperature, 2023K for the exit velocity of 0.5 m/s. The radial mole fractions of N2 and H2 at the centerline are observed to be 0.66 and 0.41 respectively at the axial distance of 10 mm. Furthermore, the width of the high temperature region of the flame is observed to be ~6.5 mm. © 2022 Proceedings of WHEC 2022 - 23rd World Hydrogen Energy Conference: Bridging Continents by H2. All rights reserved.
  • 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
    Citation - Scopus: 2
    Experimental Compliance Matrix Derivation for Enhancing Trajectory Tracking of a 2-Dof High-Accelerated Over-Constrained Mechanism
    (Springer, 2022) Paksoy, Erkan; Dede, Mehmet İsmet Can; Kiper, Gökhan
    If the positioning accuracy of the end-effector of a robot has high priority, compliance characteristics of the elements of its mechanism should be considered. Due to the external loading on the robot, the dimensions of the elements change and this leads to positioning errors for the end-effector. In this paper, an experimental test setup and an experimental procedure are described to derive the compliance characteristics of a planar 2-degree-of-freedom mechanism.
  • 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.
  • 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
    Underground Gasification in Western Black Sea Area and Thermodynamic Analysis
    (2006) Atagündüz, Gürbüz
    As known, western Black Sea carboniferous coal fields consist of two main fields: Zonguldak and Amasra. Previous research works have shown that Zonguldak area is not suitable for underground coal gasification. The joint studies done since 1994 by the Department of Geology and the Solar Energy Institute of Aegean University and, the Mineral Research and Exploration Institute of Ministry of Energy and Natural Sources have shown that the Amasra coal field is suitable with certain restrictions for the underground coal gasification. In the present work, the suitability of the Amasra - coal field for underground coal gasification will be discussed and the "Controlled Retraction of the Injection Point; CRIP"- Method which was successfully used and tested in the American field experiments will be described briefly. A brief thermodynamic analysis of the gasification process will be given which should help, as a tool, to the theoretical prediction of the underground coal gasification.