Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

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

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  • Article
    Mini modular plant design for ethylene production using Martian atmosphere on Mars
    (Elsevier, 2024) Deliismail, Özgün; Şeker, Erol
    A main shift in the competitive landscape of technology development is in 3D printing of complex articles made of variety of materials due to faster manufacturing and less human error in the production. In fact, it seems to be a viable candidate for the construction of structures for terrestrial and extraterrestrial life in future. Thus, new or damaged equipment in space explorations could be replaced instantly, and habitats could be manufactured using 3D printing in varying gravitational fields in the solar system. Among 3D printing materials, HDPE is commonly used in the projects, such as a prototype manufacturing or pipes or damp-proof membrane. This study initially focused on the preliminary design of the self-sustaining mini ethylene production plant from Martian atmosphere with scale-out architecture. UniSIM® was integrated with MATLAB® via CAPE-OPEN extension to design mini-ethylene production plant at low gravity. Ethylene capacity was found as 17.71 tons/year for 100 modules. © 2023 COSPAR
  • Article
    Eğitim yapılarında asansör trafik analizi yöntemlerinin karşılaştırılmasına yönelik bir araştırma
    (Gazi Üniversitesi, 2023) Deligöz, Dostcan; Harputlugil, Timuçin
    Purpose: Regarding elevator design in educational buildings; It is aimed to investigate the legal framework, to integrate dynamic simulation programs to design process, to compare traditional and dynamic simulation methods, to evaluate the adequacy of elevator features specified in the legislation and to determine the optimum scenarios according to the minimum requirements.Theory and Methods: Based on the findings of the literature review, which examines the issue of elevator traffic analysis together with the legislation and regulations, the carrying capacities of the elevators in the educational buildings designed by the Ministry of National Education (MNE) are tested. The stability of the system is tested by analyzing the conditions where only the disabled, disabled and building workers can be used together and all building users can use the elevators with the dynamic simulation method (with Elevate Software). The limits of the system are determined based on the waiting times during the peak usage periods. The findings of the study are evaluated according to the waiting times determined by CIBSE Guide D and the Chamber of Mechanical Engineers followed by the discussion of the outcomes.Results: The issue of elevator design has been overlooked in educational buildings, and a comprehensive elevator traffic analysis method has not been defined. For the effective use of all occupants, elevator design should be handled comprehensively with considering potentials of dynamic simulation method.Conclusion: According to the findings of the study, it is noted that the number and capacity of elevators in the legislation for educational buildings are determined only for minimum conditions and for disabled users. In addition, the legislation (considering calculation methodology) is not specific for educational buildings but related with buildings in general with public use. Considering the occupants, and their profiles of the educational buildings, a more comprehensive traffic analysis with the dynamic simulation method may enable the elevators to be designed and to be used more efficiently.
  • Article
    Citation - WoS: 11
    Citation - Scopus: 12
    Numerical Modelling Assisted Design of a Compact Ultrafiltration (uf) Flat Sheet Membrane Module
    (MDPI, 2021) Bopape, Mokgadi F.; Van Geel, Tim; Dutta, Abhishek; Van der Bruggen, Bart; Onyango, Maurice Stephen
    The increasing adoption of ultra-low pressure (ULP) membrane systems for drinking water treatment in small rural communities is currently hindered by a limited number of studies on module design. Detailed knowledge on both intrinsic membrane transport properties and fluid hydrodynamics within the module is essential in understanding ULP performance prediction, mass transfer analysis for scaling-up between lab-scale and industrial scale research. In comparison to hollow fiber membranes, flat sheet membranes present certain advantages such as simple manufacture, sheet replacement for cleaning, moderate packing density and low to moderate energy usage. In the present case study, a numerical model using computational fluid dynamics (CFD) of a novel custom flat sheet membrane module has been designed in 3D to predict fluid flow conditions. The permeate flux through the membrane decreased with an increase in spacer curviness from 2.81 L/m(2)h for no (0%) curviness to 2.73 L/m(2)h for full (100%) curviness. A parametric analysis on configuration variables was carried out to determine the optimum design variables and no significant influence of spacer inflow or outflow thickness on the fluid flow were observed. The numerical model provides the necessary information on the role of geometrical and operating parameters for fabricating a module prototype where access to technical expertise is limited.
  • Article
    Citation - WoS: 5
    Citation - Scopus: 5
    Comparison of Advanced Daylighting Systems To Improve Illuminance and Uniformity Through Simulation Modelling
    (Znack Publishing House, 2014) Kazanasmaz, Zehra Tuğçe; Fırat Örs, Pelin
    Deficiencies in daylighting performance (illuminance and uniformity) of educational facilities may cause health problems, work performance loss and excessive energy consumption. The varying nature of daylight in daily and yearly basis is a strong challenge on that matter. Advanced daylighting systems have been developed to overcome this challenge. Improving the daylighting performance of existing buildings is another difficulty in daylighting design. Daylighting design needs should be carefully considered at the initial design stages of the buildings. So, the aim of this study was to improve the illuminance and uniformity in four selected architectural design studios in Izmir. Measurements of daylight illuminance were conducted in May and June 2012. Simulation models were built in Ecotect/Radiance. To reach the best daylighting performance, simulations were carried out by Desktop Radiance with applying laser cut panels, prismatic panels and light shelves. It is considered that retrofitting efforts after the construction would be inadequate regarding daylighting, unless complying with the standards during the design process.
  • Article
    Citation - WoS: 3
    Citation - Scopus: 5
    Helenistik Kulelerde Yanal Yüke İlişkin Düzlem İçi ve Düzlem Dışı Duvar Davranışının Duvar Profilleri ve Açıklık Düzenlerine Bağlı Olarak İncelenmesi
    (Gazi Üniversitesi, 2020) Gençer, Funda; Turan, Mine; Aktaş, Engin
    Dry masonry wall profiles constructed without using bonding material between blocks are encountered in different building types dated to Greek, Hellenistic and Roman periods. Depending on development of earthquake experiences, dry masonry wall profiles vary in terms of wall thickness, number of layers, relationship of layers and size, form, organization and relationship of blocks. In this study, the construction details increasing the structural strength in watch towers constructed in Hellenistic Period are aimed to be determined. This study is limited with investigation of effect of wall profiles and opening organizations on in-plane and out-of-plane wall behaviors under lateral loading. Primarily, wall profiles and opening types of dry masonry towers in ancient Caria, Pamphylia and Cilicia regions, that have not lost authenticity and integrity or had information about their authentic form, were documented. By using gathered data, hypothetic towers with different wall profiles and opening types are designed. To determine in-plane and out-of-plane wall behavior of hypothetic towers, simulation of quasi-static tilt analysis based on equilibrium were carried out, and form changes at walls and collapse angles of towers were identified. Wall profile and opening properties effecting on structural strength under lateral loading were determinedd.
  • Article
    Citation - WoS: 1
    Citation - Scopus: 2
    Oluklu alüminyum sandviç panellerde kor yüksekliğinin enerji sönümleme kapasitesine olan etkisi
    (Gazi Üniversitesi, 2020) Kılıçaslan, Cenk; Güden, Mustafa
    In this study, energy absorbing capacity of brazed and polyurethane adhesively bonded corrugated aluminum sandwich panels were investigated. In sandwich panels, Al 1050 H14 trapezoidal zig-zag corrugated cores and face and interlayer sheets were used. Each sandwich panel has core orientation of 0 degrees/0 degrees or 0 degrees/90 degrees. The cores used in these panels were smaller, core height is about 3 mm, in contrast to conventional sandwich cores. Impact tests were conducted at 3 and 6 m/s with spherical projectors. Adhesively bonded sandwich panels were also tested at 6 m/s with flat and conical projectors. Numerical models were prepared in LSDYNA to investigated the deformation behavior of cores. Panels tested with flat and conical projectors experienced complete perforation and absorbed more energy at configuration of 0 degrees/0 degrees core orientation. However, panels tested with spherical projectors were not perforated and they absorbed more energy at configuration of 0 degrees/90 degrees core orientation. Energy absorbing capacity of the panels were also compared to the panels having 9 mm height corrugated cores. The results showed that effective collapsing length was seen to increase due to increase in core height and impact energy distributed the whole panel surface more homogenous manner.
  • Article
    Citation - Scopus: 2
    Effects of Earthquake Motion on Mechanism Operation: an Experimental Approach
    (Levrotto and Bella, 2015) Selvi, Özgün; Ceccarelli, M.; Aytar, Erman Barış
    This paper presents an experimental characterization of the effects of earthquakes on the operation of mechanical systems with the help of CaPaMan (Cassino Parallel Manipulator), which is a 3 DOF robot that can fairly well simulate 3D earthquake motion. The sensitivity of operation characteristics of machinery to earthquake disturbance is identified and characterized through experimental tests. Experimental tests have been carried out by using a slider-crank linkage, a small car model, and LARM Hand as test-bed mechanisms that have been sensored with proper acceleration or force sensors. Results are reported and discussed to describe the effects of earthquake motion on the characteristics of mechanism operation as a service application of the robotic CaPaMan system.
  • Article
    Citation - WoS: 7
    Citation - Scopus: 8
    Implementation and Experimental Verifications of Microstrip Antennas for Angular Scanning of a Doppler Radar
    (Elsevier, 2019) Karatay, Anıl; Orcan, Durmuş; Özkal, Ceren; Yaman, Fatih
    The aim of this study is to improve operational capabilities and range of the MIT-Coffee Can Doppler radar via aperture coupled Vivaldi type transmitter antenna, patch array receiver antenna, and an unequal power divider. Accordingly, a mechanical angular scanning feature for tracking multi-targets and the system integration of lightweight microstrip structures are realized for the radar. A narrow beamwidth in the receiver and a well impedance matching on the overall system to reduce return losses are achieved for the considered application. Good agreements between simulations and measurements for the fabricated antennas/divider and a successful integration of the antennas to the existing system for finding a moving target angular location is reported. It is shown that through wall identification and target velocity at scanned regions can be obtained with the proposed hardware configuration. Simulation results of antenna parameters for various number of array elements are listed which could be a useful tool for different engineering applications. (C) 2019 Elsevier GmbH. All rights reserved.
  • Article
    Citation - WoS: 22
    Citation - Scopus: 26
    Fuzzy Logic for Rainfall-Runoff Modelling Considering Soil Moisture
    (Kluwer Academic Publishers, 2015) Tayfur, G.; Brocca, L.
    This study developed Mamdani-type fuzzy logic model to simulate daily discharge as a function of soil moisture measured at three different depths (10, 20 and 40 cm) and rainfall. The model was applied to 13 km2 size Colorso Basin in central Italy for a period from October 2002 to April 2004. For each variable of soil moisture, rainfall, and discharge, 9 fuzzy subsets were employed while 30 fuzzy rules, relating the input variables (soil moisture and rainfall) to the output variable (discharge), were optimized. The model employed the min inferencing, max composition, and the centroid method. The model application results revealed that Mamdani-type fuzzy logic model can be employed to incorporate soil moisture along with rainfall to simulate discharge. Using soil moisture measured at 40 cm soil depth along with rainfall produced better simulation of discharge with NS=0.68 and R= 0.82. The performance of the model was also tested against a conceptual rainfall- runoff model of MISDc (Modello Idrologico Semi-Distribuito in continuo). MISDc couples an event-specific component with a module for continuous time soil water balance for taking into account the variable antecedent wetness conditions. The MISDc model requires estimation of seven parameters and the measurements of the hydrometeorological variables such as rainfall and air temperature. The comparative study revealed that fuzzy model performs better in capturing runoff peak rates and overall trend of high and small flooding events. © Springer Science+Business Media Dordrecht 2015.
  • Article
    Citation - WoS: 5
    Citation - Scopus: 5
    Determination of the Dill Parameters of Thick Positive Resist for Use in Modeling Applications
    (Elsevier Ltd., 2011) Roeder, G.; Liu, S.; Aygün, Gülnur; Evanschitzky, P.; Erdmann, A.; Schellenberger, M.; Pfitzner, L
    The determination of Dill parameters of thick resist is very important to improve simulation models of resist exposure and real world processes. A new extraction technique of Dill parameters based on spectroscopic ellipsometry in combination with an advanced resist exposure model is proposed for thick resist analysis. The complex refractive index of the resist is related to the relative concentration of the photoactive compound in the resist in order to describe the vertical distribution of the refractive index and the extinction coefficient. Moreover, Dill parameters are extracted by directly fitting the bleaching curves to the measured ellipsometry data. The new approach was investigated experimentally by spectroscopic ellipsometry measurements on AZ5214E resist with two moderate layer thickness values in order to verify the accuracy of the new method. Dill parameters were extracted by using this new technique and by applying resist samples subjected to different exposure doses. Possible reasons for the variation of Dill parameters depending on resist thickness are explained. Furthermore, advantages, limitations and potential improvements of the model are discussed. Finally, the impact of Dill parameter variation on image formation in the resist is demonstrated by applying the spectroscopic ellipsometer analysis results as input parameters to the lithography simulator Dr.LiTHO.