Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 21Citation - Scopus: 24Development and Mechanical Behavior of Fml/Aluminium Foam Sandwiches(Springer Verlag, 2013) Baştürk, Suat Bahar; Tanoğlu, MetinIn this study, the Fiber-Metal Laminates (FMLs) containing glass fiber reinforced polypropylene (GFPP) and aluminum (Al) sheet were consolidated with Al foam cores for preparing the sandwich panels. The aim of this article is the comparison of the flexural properties of FML/Al foam sandwich panels bonded with various surface modification approaches (silane treatment and combination of silane treatment with polypropylene (PP) based film addition). The FML/foam sandwich systems were fabricated by laminating the components in a mould at 200 A degrees C under 1.5 MPa pressure. The energy absorbtion capacities and flexural mechanical properties of the prepared sandwich systems were evaluated by mechanical tests. Experiments were performed on samples of varying foam thicknesses (8, 20 and 30 mm). The bonding among the sandwich components were achieved by various surface modification techniques. The Al sheet/Al foam sandwiches were also consolidated by bonding the components with an epoxy adhesive to reveal the effect of GFPP on the flexural performance of the sandwich structures.Article Citation - WoS: 7Citation - Scopus: 9A Smart Mass Customization Design Tool: a Case Study of a Portable Ramp for Wheelchair Users(Springer Verlag, 2020) Doğan Kumtepe, Elvan; Başoğlu, Ahmet Nuri; Çorbacıoğlu, Eda; Daim, Tuğrul Ünsal; Shaygan, AmirPortable ramps are generally used by wheelchair users, provide temporary solution to increase accessibility in their daily lives. Portable ramps should allow for modifications in terms of weight, length, load bearing capacity, ease of handling, storage and further design parameters. Different types of portable ramps can be found in the market; however, their modifications cannot go beyond just length modification, or they allow to select just some restricted width options. However, portable ramps are quite suitable for mass customization concept which helps to satisfy customer while being involved in design step. This study aims to determine the wheelchair users' expectations and correspondingly to offer a smart mass customization design tool which potential users are able to interact with easily. To this end, a case study is conducted with a rollable ramp which is designed and developed within the scope of 1512 - Entrepreneurship Multi-phase Programme (Teknogirisim Sermaye Destegi Programi) of The Scientific and Technological Research Council of Turkey (TuBITAK). The methodology and its implementation are described elaborately, and example of a parametric smart customization tool design are illustrated in this study. First, the preliminary study is explained briefly. Afterward, the desired modification parameters are determined with literature and patent survey as well as observation and interviews with the potential users. After systematic review and evaluation of user experiences, the model is assessed.Article Citation - WoS: 23Citation - Scopus: 24Spatial Effects of Transport Infrastructure on Regional Growth: the Case of Turkey(Springer Verlag, 2021) Elburz, Zeynep; Çubukçu, K. MertThe provision of infrastructure is an important policy tool for promoting regional growth and reducing regional disparities. The main reason underlying this approach is the view that transportation promotes mobility, mobility promotes trade, and trade promotes economic growth. Based on this view, Turkey has invested in transportation infrastructure to reduce the regional economic inequalities since the 1960s. Between 2004 and 2014, governments have expended approximately 65 billion dollars for road infrastructure only. We believe that investigating the recent improvements in road infrastructure with a spatial perspective in an emerging economy as Turkey is necessary to generate more effective and practical regional policies. This study attempts to measure the latest developments of transportation infrastructure by analyzing the spatial effects of road transport infrastructure on regional economy in Turkish NUTS 2 regions between 2004 and 2014. We employ an augmented Cobb-Douglas production function model and use spatial Durbin model to estimate spatial effects. Apart from previous studies that employ spatial econometric models, we create a different spatial weight matrix for each year based on inverse distance to capture the change between the years 2004 and 2014. The results reveal that road infrastructure investment has significant and positive spatial spillover effects on regional growth. Any improvement in road transport infrastructure in a region causes a GDP increase in neighboring regions. Essentially the findings expose the importance of indirect effects of road transport infrastructure and contradict with previous non-spatial and overestimated effect results in the literature.Article Citation - WoS: 6Citation - Scopus: 6Adsorbate-Induced Enhancement of the Spectral Response in Graphene/Silicon-based Schottky Barrier Photodetectors(Springer Verlag, 2020) Sahan, N.; Fidan, Mehmet; Çelebi, CemThe impact of atmospheric adsorbates on the spectral response and response speed of p-type graphene/n-type Silicon (p-Gr/n-Si) based Schottky barrier photodetectors are investigated. Wavelength resolved photocurrent and transient photocurrent spectroscopy measurements conducted under high-vacuum conditions revealed that the atmospheric adsorbates such as O-2 and H2O stuck on graphene electrode lead to hole doping in graphene and therefore shift its Fermi level towards higher energy states below its Dirac point. Such a shift in graphene's Fermi level due to adsorbates increases the zero-bias Schottky barrier height of the p-Gr/n-Si heterojunction from 0.71 to 0.78 eV. Adsorbate induced increment in the barrier height promotes the separation of photo-generated charge carriers at the depletion region and leads to an improvement in the maximum spectral response (e.g., from 0.39 to 0.46 AW(-1)) and response speed of the p-Gr/n-Si photodetector in the near-infrared region. The experimentally obtained results are expected to give an insight into the adsorbate related variations in the rectification and photo-response characters of the heterojunctions of graphene and other 2D materials with different semiconductors.Article Citation - WoS: 12Citation - Scopus: 15The Role of Loco-Regional Treatment in Long-Term Quality of Life in De Novo Stage Iv Breast Cancer Patients: Protocol Mf07-01q(Springer Verlag, 2021) Soran, Atilla; Soyder, Aykut; Özbaş, Serdar; Özmen, Vahit; Karanlık, Hasan; İğci, Abdullah; Sezgin, EfeBackground/objective Since more solid evidence has emerged supporting the effectiveness of loco-regional treatment (LRT), clinicians consider LRT a treatment option for selected de novo stage IV breast cancer (BC) patients. This is the first report on long-term quality of life (QoL) in a cohort of patients who were randomized to receive either LRT and then systemic treatment (ST) or ST alone in the protocol MF07-01. We aimed to evaluate QoL in patients living at least 3 years since randomization using scores from the SF-12 health survey. Methods SF-12 (V2) forms were completed during visits of patients who were living 36 months after the randomization. We first calculated PCS-12 (Physical Health Composite Scale) and MCS-12 (Mental Health Composite Scale) scores from de novo stage IV BC patients and compared them with the scores of patients diagnosed with stage I-III BC who lived more than 3 years. Further, PCS-12 and MCS-12 scores were compared between the LRT and ST groups with de novo stage IV BC. Additionally, general health, physical functioning, role functioning, bodily pain, vitality, mental health, and social functioning were evaluated and compared between the groups. Considering age-related changes in QoL, we also compared PCS-12 and MCS-12 scores of patients below or above 55 and 65 years of age. Responses to four additional questions (compare your physical health, mental health, daily activities, and energy currently vs. at diagnosis of BC) were recorded, considering cultural differences. Results There were 81 patients in this analysis; 68% of patients (n = 55) had LRT, and 32% (n = 26) received ST. General health was good or very good in 62% (n = 34) in the LRT group and 66% (n = 17) in the ST-only group (p = 0.63). Mean PCS-12 score was 40.8 + 1.6, and mean MCS-12 score was 43.4 + 2.0 (p = 0.34 and p = 0.54, respectively). PCS-12 and MCS-12 score difference was lower than that of the general Turkish population (PCS-12 = 49.3 + 12.8 and MCS-12 = 46.8 + 13.0) and stage I-III BC patients (PCS-12 = 51.1 +/- 0.5, MCS-12 = 45.7 +/- 0.6). PCS-12 and MCS-12 scores were similar between the LRT and ST-only groups in patients younger and older than 55 and 65, but QoL scores were much better in stage I-III BC patients younger than 65 when compared to the scores of those with de novo stage IV BC. Although treatment with or without LRT did not affect physical health, mental health, daily activities, and energy at 3 years vs. at diagnosis of BC in de novo stage IV BC patients (p > 0.05), these variables were significantly better in stage I-III BC patients (p < 0.001). Conclusion The current MF07-01Q study demonstrates that patient who had LRT has similar physical and mental health outcomes compared to ST only in a cohort of patients who lived longer than 3 years. Trial registration This study is registered on clinicaltrials.gov with identifier number NCT00557986.Article Citation - Scopus: 1Level Set Estimates for the Discrete Frequency Function(Springer Verlag, 2019) Temur, FarukWe introduce the discrete frequency function as a possible new approach to understanding the discrete Hardy-Littlewood maximal function. Considering that the discrete Hardy-Littlewood maximal function is given at each integer by the supremum of averages over intervals of integer length, we define the discrete frequency function at that integer as the value at which the supremum is attained. After verifying that the function is well-defined, we investigate size and smoothness properties of this function.Article On the Structure of Modules Defined by Opposites of Fp Injectivity(Springer Verlag, 2019) Büyükaşık, Engin; Kafkas Demirci, GizemLet R be a ring with unity and let MR and RN be right and left modules,respectively. The module MR is said to be absolutely RN-pure if M circle times NL circle times N is amonomorphism for every extension LR of MR. For a module MR, the subpurity domain of MR is defined to be the collection of all modules RN, such that MR is absolutely RN-pure. Clearly, MR is absolutely RF-pure for every flat module RF and that MR is FP-injective if the subpurity domain of M is the entire class of left modules. As an opposite of FP-injective modules, MR is said to be a test for flatness by subpurity (or t.f.b.s. for short) if its subpurity domain is as small as possible, namely, consisting of exactly the flat left modules. We characterize the structure of t.f.b.s. modules over commutative hereditary Noetherian rings. We prove that a module M is t.f.b.s. over a commutative hereditary Noetherian ring if and only if M/Z(M) is t.f.b.s. if and only if Hom(M/Z(M),S)0 for each singular simple module S. Prufer domains are characterized as those domains all of whose nonzero finitely generated ideals are t.f.b.s.Article Citation - WoS: 3Citation - Scopus: 4Affordable person detection in omnidirectional cameras using radial integral channel features(Springer Verlag, 2019) Demiröz, Barış Evrim; Salah, Albert Ali; Baştanlar, Yalın; Akarun, LaleOmnidirectional cameras cover more ground than perspective cameras, at the expense of resolution. Their comprehensive field of view makes omnidirectional cameras appealing for security and ambient intelligence applications. Person detection is usually a core part of such applications. Conventional methods fail for omnidirectional images due to different image geometry and formation. In this study, we propose a method for person detection in omnidirectional images, which is based on the integral channel features approach. Features are extracted from various channels, such as LUV and gradient magnitude, and classified using boosted decision trees. Features are pixel sums inside annular sectors (doughnut slice shapes) contained by the detection window. We also propose a novel data structure called radial integral image that allows to calculate sums inside annular sectors efficiently. We have shown with experiments that our method outperforms the previous state of the art and uses significantly less computational resources.Article Traffic Aware Cell Selection Algorithm for Tetra Trunk Based Professional Mobile Radio(Springer Verlag, 2019) Özbek, Berna; Karataş, Azad; Bardak, Erinç Deniz; Sönmez, İlkerLoad balancing and traffic management are the critical needs in cell selection decision for a better and seamless communication demands in professional mobile radios. For the cases where cell selection algorithms do not consider the traffic load, there may be call drops due to the congestion in networks or longer call setup times for the users. These undesired consequences can cause dramatic quality degradation especially for the emergency cases or public safety services. In this paper, we propose two algorithms for Tetra Trunk based professional mobile radios by considering both traffic load and received signal strength indication (RSSI) in order to reduce the significant delays while establishing transmissions. The proposed full set cell selection algorithm is prioritized to reduce the call setup time for the mobile users and the proposed reduced set cell selection algorithm is focused on minimizing the number of RSSI measurements which causes significant delay in practical professional mobile radio. We illustrate the performance results in terms of delay for Tetra Trunk based professional mobile radio.Article Citation - WoS: 21Citation - Scopus: 24Modification of Electrospun Pva/Paa Scaffolds by Cold Atmospheric Plasma: Alignment, Antibacterial Activity, and Biocompatibility(Springer Verlag, 2019) Arik, Nehir; İnan, Alper; İbiş, Fatma; Demirci, Emine A.; Karaman, Ozan; Ercan, Utku K.; Horzum, NesrinThe ongoing search for better antibacterial wound care dressings has led to the design and fabrication of advanced functional nanomaterials. Taking advantage of electrospinning and cold atmospheric plasma (CAP), free-standing nanofibrous scaffolds are promising for use in novel biomedical applications. Random and aligned polyvinyl alcohol (PVA)/polyacrylic acid (PAA) nanofiber scaffolds are fabricated by electrospinning and treated with CAP. In this study, we investigate the effects of CAP treatment on alignment, hydrophilicity, antibacterial activity, and biocompatibility in determining the surface properties of the nanofibrous scaffolds. The results of vibrational polarization spectroscopy analysis indicate that CAP treatment changes the degree of alignment of the nanofibers. Furthermore, both random and aligned CAP-treated nanofibrous scaffolds show significant antibacterial activity against the E. coli strain. The results of an in vitro scratch assay reveal that CAP treatment of PVA/PAA nanofibers has no toxic effect.