Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
Browse
60 results
Search Results
Correction Chlorinated Phosphorene for Energy Application (vol 231, 112625, 2024)(Elsevier, 2024) Hassani, Nasim; Yagmurcukardes, Mehmet; Peeters, Francois M.; Neek-Amal, Mehdi[No Abstract Available]Article Citation - WoS: 1Citation - Scopus: 1Real-Time Superficial Vein Imaging System for Observing Abnormalities on Vascular Structures(Springer, 2024) Altay, A.; Gumus, A.Circulatory system abnormalities might be an indicator of diseases or tissue damage. Early detection of vascular abnormalities might have an important role during treatment and also raise the patient’s awareness. Current detection methods for vascular imaging are high-cost, invasive, and mostly radiation-based. In this study, a low-cost and portable microcomputer-based tool has been developed as a Near-Infrared (NIR) superficial vascular imaging device. The device uses NIR Light-Emitting Diode (LED) light at 850 nm along with other electronic and optical components. It operates as a non-contact and safe infrared (IR) imaging method in real-time. Image and video analysis are carried out using OpenCV (Open-Source Computer Vision), a library of programming functions mainly used in computer vision. Various tests were carried out to optimize the imaging system and set up a suitable external environment. To test the performance of the device, the images taken from three diabetic volunteers, who are expected to have abnormalities in the vascular structure due to the possibility of deformation caused by high glucose levels in the blood, were compared with the images taken from two non-diabetic volunteers. As a result, tortuosity was observed successfully in the superficial vascular structures, where the results need to be interpreted by the medical experts in the field to understand the underlying reasons. Although this study is an engineering study and does not have an intention to diagnose any diseases, the developed system here might assist healthcare personnel in early diagnosis and treatment follow-up for vascular structures and may enable further opportunities. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2023.Conference Paper Citation - Scopus: 1Effect of Tsunami Induced Currents on Floating Pontoons With the Mooring Lines(American Society of Civil Engineers (ASCE), 2023) Ozbahceci, B.O.; Celik, H.; Girgin, E.; Yalciner, A.C.; Dogan, G.G.[No abstract available]Article Citation - WoS: 3Citation - Scopus: 3Liquid Metal-Tunable Miniaturized Bimodal Cavity for Enhanced Measurement Accuracy in the Ism Bands(Ieee-inst Electrical Electronics Engineers inc, 2024) Karatay, Anil; Yaman, FatihEnhancing measurement accuracy or reducing the effect of the neighboring modes in resonant cavities may necessitate the separation of mode frequencies. However, in ISM-band measurement configurations utilizing a rectangular or cylindrical cavity, the placement of the first two modes at 2.45 and 5.8 GHz is unattainable, necessitating the presence of additional modes in between that would potentially degrade measurement accuracy. This article begins with an analytical approach, employing Lagrange multipliers for the first time to reveal the level of separation achievable in the frequency domain between the initial two modes within these types of conventional cavities. The analytical results were also verified with a numerical grid search. Subsequently, innovative strategies have been introduced to surpass this intrinsic constraint that reduces the measurement accuracy in various applications. A novel miniaturized cavity configuration has been proposed to operate bimodally at 2.45 and 5.8 GHz and manufactured with a 3-D printer. It has been ensured that there are no physical modes present in between, and measurements of the structure have been conducted. Another notable innovation of the article is the capability of tuning the proposed cavity structure by means of liquid metal displacement. Thus, a more flexible tuning method compared to mechanical tuning techniques can be achieved, enabling precise adjustment of the desired measurement frequency. Good agreement between the simulation and measurement results has been reported.Conference Paper Magnetic Levitation-Based Endothelial Cell Sorting(Institute of Electrical and Electronics Engineers Inc., 2023) Ozcan, H.A.; Kecili, S.; Tekin, H.C.Cell sorting for rare cells is crucial for diagnostic purposes. Circulating Endothelial Cells (CECs) can be used as cardiovascular disease markers. Due to the rareness of the CECs in the blood, an accurate, easy, cost and time-effective sorting method is a need. Magnetic levitation is a promising technique for observing differences in the average height of endothelial and white blood cells which does not require any labeling. This study aims to show that the magnetic levitation principle can be used for sorting endothelial cells from the blood. By using paramagnetic medium concentrations of 10 mM and 50 mM, the average levitation height between HUVECs used as a model endothelial cells and U937 cells used as model of white blood cells was measured as 65 μm and 32 μm, respectively. Since there is a significant difference in levitation height for HUVECs and U937 cells, magnetic levitation technology exhibits promising potential for the precise sorting of endothelial cells. © 2023 IEEE.Article Citation - WoS: 1Citation - Scopus: 1An Iris Segmentation Scheme Based on Bendlets(Springer London Ltd, 2023) Aghazadeh, Nasser; Abbasi, Mandana; Noras, ParisaDue to the effect of agents such as ambiance, transition channel, and other agents, images are polluted by noise during collection, transition, and compaction, leading to decrease image quality. Noise can decrease the accuracy of the next stages of image processing systems. Therefore, one of the vital stages in the novel processing systems is denoising. This article offers a novel image denoising approach using bendlets. Other multi-scale transformations (such as wavelets, curvelets, and shearlets) cannot recognize properties such as location, direction, and curvature of discontinuities well in piecewise stable images. To solve this problem, bendlets are suggested in this article. Bendlets differ from other multi-scale transformations in that an additional bending parameter is utilized for recognizing the curvature of discontinuities. Bendlets need a fewer number of coefficients to identify curvatures than other multi-scale transformations. Furthermore, they help to make the edges more obvious. The suggested approach is utilized on the UBIRIS.V2 database. It earns better accuracy and stability than other multi-scale transformations.Article Citation - WoS: 3Citation - Scopus: 3Light-Induced Synthesis of Single-Crystalline Gold Microplates in an Open System(Amer Chemical Soc, 2023) Akkuş, Betül; Mert Balcı, FadimeBottom-up synthesis of large single-crystalline gold microplates is of key importance to catalysis, nanophotonics, bioengineering, and plasmonics. However, easy, low-cost, room-temperature, and high-yield synthesis of large gold microplates with several micrometers in lateral size and a few tens of nanometers in thickness by using photochemical synthesis in an open system is still challenging. We herein report on an easy and cost-effective photochemical synthesis of single-crystalline gold microplates with lateral sizes up to around 40 mu m and tens of nanometers in thickness in a few hours of reaction time in an open system containing a lyotropic liquid crystal, which is formed by self-assembly of 10-lauryl ether in a strong acid, sulfuric acid, along with water. We have found that by changing the reaction parameters, such as the reaction time, the concentration of gold ions in the liquid crystal, etc., the thickness and size of the microplates can be easily controlled. Most importantly, the liquid crystalline phase is completely preserved after completion of the photochemical reaction. The microplates can be easily isolated and transferred to different media such as alcohol and water for further studies, or they can be immediately used on a substrate after completion of the reaction. The results obtained in this study will allow us to understand the growth mechanism of gold microplates in open systems, and they will find applications in a variety of critical areas, such as plasmonics, nanophotonics, and catalysis.Article Citation - WoS: 7Citation - Scopus: 9Politics of Waiting for Transformation in Protracted Urban Renewal Projects in Turkey(Sage Publications Ltd, 2023) Ay, Deniz; Penpecioglu, MehmetThis paper explores the politics of 'waiting' as a mode of governance in large-scale urban redevelopment projects. In designated renewal areas, residents/landowners are often subject to several episodes of waiting: waiting for the public authority for information on redevelopment visions; waiting for the plans and projects to become public; waiting for the court ruling if they appeal the plans; waiting for demolition upon plan approvals; and, finally, waiting for the constructions to be completed. Given the complexity of actors and institutions involved in the waiting, it becomes a conflictual political process. This prolonged waiting leads to an ongoing temporariness and precarious spaces of urban renewal. The course of waiting affects the reorganization of the city space now and in the future. We analyze two protracted urban renewal projects from Turkey, Fikirtepe in Istanbul and Karabaglar in Izmir, to explore how residents' decade-long waiting for urban change are shaped and how these diverse waiting experiences lead to different outcomes for the progression of the state-imposed urban renewal agendas. While Karabaglar residents have unified around active bottom-up resistance from the beginning to challenge the project-based plans the central government imposed, Fikirtepe residents pursued individual-level negotiations with developers to maximize private returns following the zoning incentives the public authority gave. Despite the socio-spatial similarities between these designated urban renewal project sites, variances in residents' collective waiting strategies have led to different urban politics around project-based urban change.Conference Object Serum Creatinine Detection in a Microfluidic Chip Using a Smartphone Camera(Chemical and Biological Microsystems Society, 2022) Karakuzu, B.; Tarim, E.A.; Tekin, H.C.We present a microfluidic chip platform to detect serum creatinine levels using the enzyme-linked immunosorbent assay (ELISA) principle. In the platform, surface modified microfluidic channel sensitively captured target molecules from the serum sample, and then ELISA protocol was applied inside the channels. Afterward, the blue color formed as a result of the enzymatic reaction was measured via a smartphone camera. The proposed strategy allows the detection of creatinine rapidly in a minute amount of the serum samples without the need for expensive equipment. Thus, chronic kidney disease (CKD) could be monitored easily at point-of-care settings via the proposed creatinine detection strategy. © 2022 MicroTAS 2022 - 26th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved.Conference Object Magnetic Levitation-Based Viscosity Measurement in a Microcappilary Channel(Chemical and Biological Microsystems Society, 2022) Doyran, O.; Tekin, H.C.Viscosity, has been known as the key rheological parameter, to characterize biological, chemical and physical material properties. In this work, we have developed a magnetic levitation-based viscosity measurement method in a microcapillary channel. For this purpose, polymer microspheres are utilized as microsensors to correlate solution viscosity to microspheres' velocity while microspheres are balanced at a stable levitation position. This inexpensive and practical system enables rapid viscosity measurement from low amount of sample. © 2022 MicroTAS 2022 - 26th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved.