190 results
Search Results
Now showing 1 - 10 of 190
Article Citation - WoS: 13Citation - Scopus: 13Supply chain resilience in the tourism and hospitality industry: A comprehensive examination of driving and restraining forces(Elsevier Sci Ltd, 2024) Erol, Ismail; Oztel, Ahmet; Dogru, Tarik; Peker, Iskender; Neuhofer, Irem Onder; Benli, TolgaSupply chain disruptions and a lack of resilient supply chains have adverse impact on the global economy. Particularly, complex nature of the tourism and hospitality industry makes it even more susceptible to failure when supply chain resiliency is rather low or does not exist. However, despite its significance, a comprehensive and systematic examination of building resilience in tourism and hospitality supply chains (THSCs) is lacking in the extant literature. The purpose of this study is to develop a comprehensive framework that outlines the driving and restraining forces for building resilient THSCs. The decision framework proposed in this study integrates rough interval valued neutrosophic (RIVN) force field theory of change with RIVN-ISM-MICMAC methodology. The results showed that the restraining forces, such as lack of effective regulations and incentives and effective organizational and supply chain policies are the primary factors that constrain improving resilience in THSCs. Theoretical and practical implications are discussed.Article Citation - WoS: 6Citation - Scopus: 6Sns2 and Ho-Doped Sns2 Thin Films: Synergistic, Dft, Photocatalytic, and Antibacterial Studies(Elsevier Sci Ltd, 2024) Radja, Imane; Khane, Yasmina; Oliveira, Marisa C.; Longo, Elson; Ribeiro, Renan A. P.; Isik, Mehmit; Khan, Mohammad MansoobThis study investigates Ho-doped tin disulfide (Ho-SnS2) thin films prepared via spray coating, focusing on varying Ho doping levels (0 at. %, 2 at. %, and 4 at. %). Structural analysis through XRD and SEM showcased enhanced crystallinity and morphology in Ho-SnS2 films. Raman and XPS studies provided insight into the film's composition and chemical states. The antibacterial properties of the films were investigated using a bacterial growth inhibition assay. The results showed significant antibacterial activity against Gram-positive and Gram-negative bacteria, highlighting the potential applications of Ho-SnS2 thin films in antibacterial coatings. Ho-SnS2 films exhibited superior photocatalytic activity and antibacterial properties compared to SnS2 films, attributed to efficient charge separation. DFT analysis proposed a mechanism for the antibacterial activity. These findings highlight the efficacy of the spray coating technique in producing Ho-SnS2 films and the potential of Ho-SnS2 films for diverse applications like photocatalysis and antibacterial coatings.Article Citation - WoS: 12Citation - Scopus: 13Performance of the Au/Mgo Photovoltaic Devices(Elsevier Sci Ltd, 2015) Khanfar, H. K.; Qasrawi, A. F.A 100 mu m thick MgO film is used to design a metal semiconductor metal device. The device is characterized by means of current voltage characteristics in the dark and under various light energies in the photon energy range of 3.70-2.15 eV. A photovoltaic effect presented by an open circuit voltage of 0.12-0.47 V. short circuit current density of 3.9-10.5 mu A/cm(2), quantum efficiency of 0.662-0.052, and responsivity of 0.179-0.024 A/W under photoexcitation optical power of 2.2-28.2 mu W is observed. The device was also tested as a UV optical communication component. The test revealed a wide range of tunability and sensitivity for microwave resonant frequencies of 0.5 and 2.9 GHz. The differential resistance of the device exhibited different values at each applied ac signal frequency. When the frequency is fixed, the illuminated to the dark current ratio remained constant for all signal powers in the range of 0.00-20.0 dBm. (C) 2014 Elsevier Ltd. All rights reserved.Article Citation - WoS: 14Citation - Scopus: 15Discrete Time Series-Parallel System and Its Optimal Configuration(Elsevier Sci Ltd, 2021) Dembinska, Anna; Eryilmaz, SerkanThis paper is concerned with properties of series-parallel systems when the component lifetimes have discrete failure time distribution. For a series-parallel system consisting of a specified number of subsystems, we particularly focus on the number of failed components in each subsystem at the time when the system fails. Each subsystem is assumed to have identical components while different subsystems have different types of components. Assuming all components within the system are independent, we obtain exact distributions of the number of failed components at the time when the system fails. For the special case when the components have phase-type failure time distributions, matrix-based expressions are derived for the quantities under concern. The results are used to obtain optimal configuration of the series-parallel system which is replaced at failure.Article Citation - WoS: 31Citation - Scopus: 37Effect of Initial Water Content and Calcination Temperature on Photocatalytic Properties of Tio2 Nanopowders Synthesized by the Sol-Gel Process(Elsevier Sci Ltd, 2015) Agartan, Lutfi; Kapusuz, Derya; Park, Jongee; Ozturk, AbdullahThe effects of initial water content and calcination temperature on sol gel synthesized TiO2 powders were studied. Mother solutions had water/Ti-precursor mole ratios (R ratio) of 1, 5, 10, and 50. Dried aerogels were calcined for 3 h at temperatures of 300, 400, and 500 degrees C to obtain crystallized TiO2 nanopowders in the range of 15-30 nm. PE-scanning electron microscopy and X-ray diffraction techniques were employed to investigate the morphological and structural properties of the nanopowders synthesized. Profound effect of gel viscosity was observed on the formation mechanism and extent of crystallinity in the powders. Methylene blue degradation test results suggest, photocatalytic performance is enhanced as initial water content and calcination temperature increased. Band-gap energy of the powders ranged from 3.09 to 3.27 eV. Overall, this study shows that initial water content and calcination regime have a profound effect on the phase assembly, crystallite size, band-gap energy, and photocatalytic performance of sol gel synthesized TiO2 nanopowders. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.Article Citation - WoS: 29Citation - Scopus: 36Syntactic Complexity in L2 Learners' Argumentative Writing: Developmental Stages and the Within-Genre Topic Effect(Elsevier Sci Ltd, 2021) Atak, Nesrin; Saricaoglu, AyselThe developmental patterns that learners follow as their language develops in syntactic complexity has gained much attention in L2 writing research recently. This study aims to contribute to the growing body of empirical literature testing the hypothesis that learners move through a set of stages in their use of complex structures for L1 Turkish learners of L2 English (Biber et al., 2011). It also aims to contribute to the limited literature on the within-genre topic effect on syntactic complexity. Complexity developmental stages of 90 intermediate level L1 Turkish learners were examined in their argumentative essays on three different topics (cell phones, online learning, and death penalty). Our findings showed that learners were developmentally in Stage 2 and Stage 3, with frequent use of finite adverbial clauses, attribute adjectives embedded in the noun phrase, and prepositional phrases as adverbials within the clause, which is in line with their proficiency level. Thus, our findings conform to the hypothesized stages of complexity development. Our findings also illustrated a significant effect of the death penalty topic on learners' complexity developmental stages, which is probably due to its greater cognitive demands as a more impersonal topic than the others.Article Citation - WoS: 99Citation - Scopus: 113Flexural Behavior of Lightly and Heavily Reinforced Steel Fiber Concrete Beams(Elsevier Sci Ltd, 2015) Mertol, Halit Cenan; Baran, Eray; Bello, Hussain JibrilFlexural behavior of lightly and heavily reinforced steel fiber concrete beams was investigated. The test series consisted of 20 singly reinforced beams having 180 x 250 x 3500 mm dimensions. The main parameters in the testing program were the type of concrete and the amount of longitudinal reinforcement. Ten different longitudinal reinforcement ratios (with a minimum of 0.2% and a maximum of 2.5%) covering the range from under-reinforced to over-reinforced beam behavior were used in the testing program. Two specimens were cast for each longitudinal reinforcement ratio, one specimen using conventional concrete (CC) and another specimen using steel fiber reinforced concrete (SFRC). Load-deflection behaviors were obtained and evaluated in terms of ultimate load, ultimate deflection, service stiffness, post-peak stiffness, and flexural toughness. The results indicate that the use of SFRC increases the ultimate load and service stiffness of the beams slightly compared to that of CC specimens. As reinforcement ratio increases, the ultimate deflection of SFRC specimens becomes significantly greater than that of CC specimens. For over-reinforced sections, the post-peak stiffness of the SFRC specimens is observed to be significantly lower than that of CC specimens. The flexural toughness of SFRC specimens is greater than that of CC specimens with the difference being significantly larger for over-reinforced sections. Experimental load-deflection relationships were also compared to the load-deflection curves obtained from sectional analyses based on strain compatibility and best fit stress-strain relationships for SFRC in tension and compression. (C) 2015 Elsevier Ltd. All rights reserved.Article Citation - WoS: 31Citation - Scopus: 37Behavior of Steel-Concrete Partially Composite Beams With Channel Type Shear Connectors(Elsevier Sci Ltd, 2014) Baran, Eray; Topkaya, CemThis paper summarizes the findings of an experimental study investigating the flexural behavior of partially composite beams incorporating channel type shear connectors. Results from monotonic load testing of four full-scale steel-concrete composite beams and a steel beam are presented. The main effort focused on identifying the variation of strength and stiffness properties of beams with various degrees of partial composite action. Behavior of channel shear connectors in the composite beam specimens is related to those previously obtained from push-out tests of similar connectors. Finally, recommendations of the related AISC Specification on the strength and stiffness of composite beams are used for the assessment of the influence of the degree of partial composite action on flexural behavior. The experimental results revealed that even for beams with relatively low degree of partial composite action, major improvement on moment capacity and stiffness was obtained as compared to the steel specimen. The measured moment capacity of both the partially composite and fully composite beams agreed acceptably with the calculated capacities. The effective moment of inertia and the lower bound moment of inertia as specified by the AISC Specification were observed to overestimate the measured flexural stiffness of beams for all degrees of partial composite action investigated. (C) 2014 Elsevier Ltd. All rights reserved.Article Citation - WoS: 19Citation - Scopus: 21Plateau Honing of a Diesel Engine Cylinder With Special Topography and Reasonable Machining Time(Elsevier Sci Ltd, 2020) Sadizade, Babak; Araee, Alireza; Oliaei, Samad Nadimi Bavil; Farshi, Vahid RezaeizadDeep valleys and flattened peaks are essential characteristics of the finished cylinder bore surface, which is known as the plateau surface. Generally, a honing process is done in three steps to achieve a plateau surface, which is costly and time-consuming and acts as a bottleneck for cylinder block machining line. The real challenge is to select optimum levels of honing process parameters to achieve desired surface characteristics with minimum machining time. The aim of this study is to examine the influence of the input parameters of the honing process on the surface texture of diesel engine cylinder bore. The Rk family parameters are used for surface roughness evaluation and the honing crosshatch angle, in accordance with engine design requirements, which was fixed for all experiments. Optimization by means of the desirability function technique allowed determining most appropriate conditions to desirable roughness (surface quality) and/or minimize machining time (productivity). Based on the findings of this study the conventional three-stage honing process has been replaced by the two-stage process. Using the proposed two-stage honing process the intended plateau surface in cylinder bores are achieved and a remarkable reduction in the honing process time is obtained. Consequently, the process efficiency is improved significantly.Article Citation - WoS: 13Citation - Scopus: 13Crustal Thickness in the Black Sea and Surrounding Region, Estimated From the Gravity Data(Elsevier Sci Ltd, 2021) Bilim, Funda; Aydemir, Attila; Ates, Abdullah; Dolmaz, M. Nuri; Kosaroglu, Sinan; Erbek, EzgiIn this research, the crustal thickness (Moho depth) variations in the Black Sea and surrounding region were calculated from the regional gravity anomaly data using an empirical equation. The data were obtained from the open source of Bureau Gravimetrique International (BGI) in digitized form. The gravity anomaly values are changing from 80 mGal in the onshore Black Sea region in Turkey to 260 mGal in the deeper parts of the sea. Maximum gravity anomaly indicates a consistent pattern in the offshore Black Sea and anomaly pattern follows the shape of the shoreline. The pattern is consistent with the deeper parts in the marine area and the eastern anomaly extends into the Russian territory between NW of Georgia and SE of the Crimean Peninsula. The crustal thickness map indicates almost the same trends. In this map, the minimum crustal thickness is about 10 km around the mid of the Shatsky Ridge, close to the coastal regions of SE Russia and the second thinnest (12 km) place is located around the Western Black Sea Basin. The maximum thicknesses are represented with the 34-36 km contours in the onshore Eastern Black Sea region and east of Anatolia. On the other hand, the maximum crustal thickness to the north can reach up to 28 km around the Sea of Azov and to the east. The thickness variations are generally related with the main tectonic trends in this region. The Analytic Signal (AS) and maxima points of the horizontal gradients (maxspots) maps constructed from the gravity anomalies are also prepared in this research to see if these anomaly trends follow the tectonic lines. The regions of maximum and minimum crustal thicknesses are well-consistent with the AS anomalies and boundaries of the bifocal thin crustal sections coinciding with the Eastern and Western Black Sea basinal parts are surrounded with the maxspots. The northern thick crustal region around the southern margin of the Indolo-Kuban Basin is also surrounded by the maxspots. It is possible to claim that the maxspots map from the horizontal gradient of Bouguer anomalies reflects the boundaries of the main tectonic units in the Black Sea Region. Particularly, southern boundary of the Scythian Platform, southern boundary of the Shatsky Ridge and Great Caucasus thrust are distinctive and easy to follow in the maxspots map.
