Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
Browse
46 results
Search Results
Article Citation - WoS: 8Citation - Scopus: 14Partial Gravity Compensation of a Surgical Robot(SAGE Publications Inc., 2021) Maaroof, Omar Waleed Najm; Saeed, Saad Zaghlul; Dede, Mehmet İsmet CanSurgical robots are safety-critical devices that require multiple domains of safety features. This article focuses on the passive gravity compensation design optimization of a surgical robot. The limits of this optimization are related with the safety features including minimization of the total moving mass/inertia and compactness of the design. The particle swarm optimization method is used as a novel approach for the optimization of a parallel remote-center-of-motion mechanism. A compact design is achieved by partially balancing the mechanism, which also decreases the torque requirements from the actuators. © The Author(s) 2021.Article Citation - WoS: 26Citation - Scopus: 28Osteoconductive 3d Porous Composite Scaffold From Regenerated Cellulose and Cuttlebone-Derived Hydroxyapatite(SAGE Publications Inc., 2019) Palaveniene, Alisa; Tamburacı, Sedef; Kimna, Ceren; Glambaite, Kristina; Baniukaitiene, Odeta; Tıhmınlıoğlu, Funda; Liesiene, JolantaRecently, usage of marine-derived materials in biomedical field has come into prominence due to their promising characteristics such as biocompatibility, low immunogenicity and wide accessibility. Among these marine sources, cuttlebone has been used as a valuable component with its trace elemental composition in traditional medicine. Recent studies have focused on the use of cuttlebone as a bioactive agent for tissue engineering applications. In this study, hydroxyapatite particles were obtained by hydrothermal synthesis of cuttlebone and incorporated to cellulose scaffolds to fabricate an osteoconductive composite scaffold for bone regeneration. Elemental analysis of raw cuttlebone material from different coastal zones and cuttlebone-derived HAp showed that various macro-, micro- and trace elements - Ca, P, Na, Mg, Cu, Sr, Cl, K, S, Br, Fe and Zn were found in a very similar amount. Moreover, biologically unfavorable heavy metals, such as Ag, Cd, Pb or V, were not detected in any cuttlebone specimen. Carbonated hydroxyapatite particle was further synthesized from cuttlebone microparticles via hydrothermal treatment and used as a mineral filler for the preparation of cellulose-based composite scaffolds. Interconnected highly porous structure of the scaffolds was confirmed by micro-computed tomography. The mean pore size of the scaffolds was 510 mu m with a porosity of 85%. The scaffolds were mechanically characterized with a compression test and cuttlebone-derived HAp incorporation enhanced the mechanical properties of cellulose scaffolds. In vitro cell culture studies indicated that MG-63 cells proliferated well on scaffolds. In addition, cuttlebone-derived hydroxyapatite significantly induced the ALP activity and osteocalcin secretion. Besides, HAp incorporation increased the surface mineralization which is the major step for bone tissue regeneration.Article Citation - WoS: 13Citation - Scopus: 17Design of Dimensionally Stable Composites Using Efficient Global Optimization Method(SAGE Publications Inc., 2019) Aydın, Levent; Aydın, Olgun; Artem, Hatice Seçil; Mert, AliDimensionally stable material design is an important issue for space structures such as space laser communication systems, telescopes, and satellites. Suitably designed composite materials for this purpose can meet the functional and structural requirements. In this paper, it is aimed to design the dimensionally stable laminated composites by using efficient global optimization method. For this purpose, the composite plate optimization problems have been solved for high stiffness and low coefficients of thermal and moisture expansion. Some of the results based on efficient global optimization solution have been verified by genetic algorithm, simulated annealing, and generalized pattern search solutions from the previous studies. The proposed optimization algorithm is also validated experimentally. After completing the design and optimization process, failure analysis of the optimized composites has been performed based on Tsai-Hill, Tsai-Wu, Hoffman, and Hashin-Rotem criteria.Article Citation - WoS: 3Citation - Scopus: 3Energy Performance Assessment in Terms of Primary Energy and Exergy Analyses of the Nursing Home and Rehabilitation Center(SAGE Publications Inc., 2019) Hancıoğlu Kuzgunkaya, EbruThis paper concerns with the energy analysis (based on primary energy) and exergy analysis of Narlıdere Nursing Home and Rehabilitation Center (NNHRC) in İzmir, Turkey that was chosen as a sample public building. The Center services as a nursing and rehabilitation center for the aged and it also includes a geriatric division operating as a hospital. The Center was analyzed using the actual energy consumption data derived from several energy audits. Energy efficiency (according to the primary energy ratio) and exergy efficiency of the facility were calculated to be 59% and 14%, respectively. The results have indicated that the exergy efficiencies of space heating and cooling have the lowest values compared with the other units of facility. Specific primary energy consumption and specific exergy consumption of the facility were found to be 271.91 kWh/m2 year and 290.23 kWh/m2 year, respectively. Sustainability index value of the overall NNHRC was found to be 1.621.Article Citation - WoS: 6Citation - Scopus: 7Aerodynamic Optimization of Through-Flow Design Model of a High By-Pass Transonic Aero-Engine Fan Using Genetic Algorithm(SAGE Publications Inc., 2018) Kor, Orçun; Acarer, Sercan; Özkol, ÜnverThis study deals with aerodynamic optimization of a high by-pass transonic aero-engine fan module in a through-flow inverse design model at cruise condition. To the authors’ best knowledge, although the literature contains through-flow optimization of the simplified cases of compressors and turbines, an optimization study targeting the more elaborate case of combined transonic fan and splitter through-flow model is not considered in the literature. Such a through-flow optimization of a transonic fan, combined with bypass and core streams separated by an aerodynamically shaped flow splitter, possesses significant challenges to any optimizer, due to highly non-linear nature of the problem and the high number of constraints, including the fulfillment of the targeted bypass ratio. It is the aim of this study to consider this previously untouched area in detail and therefore present a more sophisticated and accurate optimization environment for actual bypass fan systems. An in-house optimization code using genetic algorithm is coupled with a previously developed in-house through-flow solver which is using a streamline curvature technique and a set of in-house calibrated empirical models for incidence, deviation, loss and blockage. As the through-flow models are the backbone of turbomachinery design, and great majority of design decisions are taken in this phase, such a study is assessed to result in significant guidelines to the gas turbine community.Article Citation - WoS: 10Citation - Scopus: 11Analysis of the Relationship Between Daylight Illuminance and Cognitive, Affective and Physiological Changes in Visual Display Terminal Workers(SAGE Publications Inc., 2019) Öner, Merve; Kazanasmaz, Zehra Tuğçe; Leccese, F.; Salvadori, G.This study explored the impact of daylight illuminance on cognitive load during visual display terminal use by means of various physiological, performance and subjective measures. Repeated-measures design was adopted to identify the impact of variations in daylight levels that were manipulated through the shading system configurations (shading-on; shading-off). A total of 30 subjects performed visual and cognitive demanding tests. Performance measures were supported by subjective data and eye-related measures during the experimental analysis. Results revealed that the use of a shading system had positive impact on sustained attention. Concerning ocular measures, percentage of eye closure values showed opposite tendencies among vigilance and sustained attention demanding tests. Eye aspect ratio-max and blink duration were significantly correlated with reported glare sensation. In all tests, eye aspect ratio-max was found significantly higher in lower illuminances. Search velocity was significantly correlated with ocular variables in higher illuminances whereas sustained attention showed an opposite trend. This, initially, explains that even slight differences in daylight illuminance might have distinctive effects on the relationship between different groups of assessment variables while measuring cognitive load. Secondly, it proves the significance of carrying out sensitive experiments in terms of both light levels and test characteristics.Article Citation - WoS: 21Citation - Scopus: 27Exploring the Impact of External Shading System on Cognitive Task Performance, Alertness and Visual Comfort in a Daylit Workplace Environment(SAGE Publications Inc., 2019) Leccese, F.; Salvodori, G.; Öner, Merve; Kazanasmaz, Zehra TuğçeThe authors examined the effect of external shading system on cognitive performance, alertness and visual comfort of visual display terminal (VDT) users under two realistic office lighting settings in this study. Daylight was the source of illumination being considered as the most significant and preferred one. A total of 26 participants performed visual and cognitive demanding tasks as well as providing subjective alertness, performance and visual evaluations in a full-scale mock-up VDT workstation. Two trials (with and without shading system) were executed during one experimental session. Results revealed that the use of a shading system improves the performance of a user on colour-naming task requiring sustained attention, while no differential effects were observed on tasks involving other cognitive skills such as search velocity and vigilance. Within-subject performance differences were more pronounced during morning hours. Higher performance was reported in some cognitive tests when the subjective sensation of visual discomfort was lower.Article Citation - WoS: 7Citation - Scopus: 9Fuzzy Logic Model for the Categorization of Manual Lighting Control Behaviour Patterns Based on Daylight Illuminance and Interior Layout(SAGE Publications Inc., 2019) Cılasun Kunduracı, Arzu; Kazanasmaz, Zehra TuğçeIn considering total building energy consumption, lighting plays an important role in shaping energy consumption and use. Although key strategies (such as energy efficient lighting products, lighting control systems and energy simulation software) are developed so far, such attempts may be unsuccessful unless users are not taken into consideration. Users’ behaviours and their manual lighting control actions depend on various factors, though within the scope of this study manual lighting control behaviour was analysed only in terms of interior layout and daylight illuminance. Three private offices in Izmir Institute of Technology were monitored using illuminance metres and occupancy/light detectors under eight different interior layout conditions. In relation to change of interior layout and daylight penetrations, users’ manual lighting control behaviours were monitored. The obtained data were then used to construct a fuzzy logic model in MATLAB FIS editor. A fuzzy logic algorithm was applied to classify behaviour patterns about the tendency to turn on the lights. This kind of prediction of the light usage tendency regarding the occupancy is aimed to foresee the ‘possible’ manual lighting control behaviour within given conditions. The gathered classification can be used further in future studies of manual lighting control behaviour and energy-saving estimations/simulations.Article Citation - WoS: 7Citation - Scopus: 7Ankaferd Influences Mrna Expression of Iron-Regulated Genes During Iron-Deficiency Anemia(SAGE Publications Inc., 2018) Güleç, Afife; Güleç, ŞükrüAnkaferd Blood Stopper (ABS) comprises a mixture of plants and stops bleeding via forming a protein network by erythroid aggregation. Bleeding causes reduction of iron levels in body. It has been indicated that ABS contains significant amount of iron. Thus, we investigated the biological activity of ABS-derived iron on iron-regulated genes during iron-deficiency anemia (IDA). IDA We selected Caco-2 and HepG2 cell lines as in vitro models of human intestine and liver, respectively. Iron deficiency anemia was induced by deferoxamine. The cells were treated with ferric ammonium citrate (FAC) and ABS. Messenger RNA levels of iron-regulated genes were analyzed by quantitative reverse transcription polymerase chain reaction to elucidate whether iron in ABS behaved similar to inorganic iron (FAC) during IDA. The results showed that ABS-derived iron influenced transcriptions of iron-regulated marker genes, including divalent metal transporter (Dmt1), transferrin receptor (TfR), ankyrin repeat domain 37 (Ankrd37), and hepcidin (Hamp) in IDA-induced Caco-2 and HepG2 cells. Our results suggest that when ABS is used to stop tissue bleeding, it might have an ability to reduce levels of IDA.Article Citation - WoS: 9Citation - Scopus: 10Experimental Studies of Autoignition and Soot Formation of Diesel Surrogate Fuels(SAGE Publications Inc., 2013) Diez, Alvaro; Crookes, Roy J.; Lovas, TereseComputational simulation has undergone vast development for internal-combustion engine research as a time- and costsaving tool. Yet combustion simulation for conventional hydrocarbon petroleum fuels faces difficult challenges since such fuels have very complex compositions, consisting of many different molecular species, for which data are sparse. The use of surrogate fuels for combustion simulation could provide a solution to this problem. In this investigation, n-heptane and mixtures of n-heptane and toluene were studied within a broad range of potential surrogate diesel fuels, and the ignition delay and soot formation trends were compared with those of diesel fuel. Ignition delays show good agreement with those for diesel fuel and it was also possible to replicate partially the soot formation behaviour for certain engine conditions. Further investigation is needed to find a surrogate fuel that closely matches over the range of operating conditions of a diesel engine.