4653 research outputs found
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CVD graphene/SiC UV photodetector with enhanced spectral responsivity and response speed
No full textA self-powered, high-performance graphene/Silicon Carbide (G/4H-SiC) ultraviolet Schottky junction photodetector has been fabricated, and the effect of using monolayer and bilayer graphene on the device performance parameters was investigated. P-type graphene sheets were grown by the chemical vapor deposition (CVD) method, while 4H-SiC material consists of an epilayer structure of n-/n+ on bulk n-SiC. Two photodetector devices have been studied, one with monolayer graphene (MLG) and the other with bilayer graphene (BLG). The proposed photodetector structure reveals the highest spectral responsivity known of a G/4H-SiC UV photodetector so far. Electronic and optoelectronic characterizations were done under an ultraviolet wavelength range from 240 to 350 nm. The results show two spectral responsivity maxima (Rmax) at 285 nm and 300 nm wavelengths. Exhibiting two maxima in spectral responsivity and detectivity is caused by the constructive and destructive interference effects of multiple reflections at the SiC epilayer's interfaces. The photodetector devices exhibit high spectral responsivity (R - 0.09 AW-1), maximum detectivity (D* - 2.9 x 1012 Jones), and minimum noise equivalent power (NEP - 0.17 pWHz-1/2) in both devices. Using bilayer graphene instead of monolayer showed no significant change in both the photogenerated current and the spectral responsivity due to the higher absorption coefficient of bilayer graphene, however, it exhibited a significant improvement in the response speed. The response speed was found to increase by 50 % when bilayer graphene was used as a hole collecting electrode in the G/4H-SiC junction. This is because bilayer graphene creates a narrower depletion layer and higher electric field, which promotes efficient charge separation and recombination.Engineering, Electrical & Electronic || Instruments & Instrumentatio
Proposal of novel exergy-based sustainability indices and case study for a biomass gasification combine cycle integrated with liquid metal magnetohydrodynamics
No full textExergy is considered a way to sustainability. Exergy-based analyses have been recently widely used for performance assessment and comparison purposes of energy systems from production to end-user while different sustainability related indices or indicators including exergetic concepts have been developed in the literature. In this regard, the present study proposed five different indices: (i) Exergetic Fuel Based Environmental Remediation Index (X), (ii) Exergetic Product Based Environmental Remediation Index (delta), (iii) Exergetic Fuel Based Total Environmental Remediation Index (beta), (iv) Exergetic Product Based Total Environmental Remediation Index (alpha), and (v) Improved Sustainability Index (ISI). These indices were applied to a novel Biomass-integrated Gasification Combine Cycle (BIGCC) integrated with Liquid Metal Magnetohydrodynamics (LMMHD). They allowed to perform a more complete environmental analysis by considering the exergetic cost of environmental remediation of the process. The average exergy efficiency values for the BIGCC, LMMHD and the overall system were determined as 0.491, 0.222 and 0.688 under daily ambient temperatures for a year and different air to fuel ratio (AFR) conditions, respectively. The average values for.X, beta, delta, alpha and ISI were 1.636, 2.389, 1.949, 2.848 and 0.513, respectively.Engineering, Environmental || Engineering, Chemica
Viewpoint Dependency in Dynamic Events: Spatial Details Are Not Registered When There Are Multiple Actors Present in a Visual Scene
No full textPsychology, Multidisciplinar
Robust low-rank learning multi-output regression for incipient sediment motion in sewer pipes
No full textThe existing incipient sediment motion models typically apply conventional regression methods considering either velocity or shear stress. In the current study, incipient sediment motion is analyzed through a simultaneous and joint analysis of velocity and shear stress using the robust low-rank learning (RLRL) multi-output regression technique. Moreover, the experimental data compiled from five different channels are utilized to develop a generic incipient sediment motion model valid for a channel of any cross-sectional shape. The efficiency of the developed method is examined and compared against the available conventional regression models. The experimental results indicate that the RLRL model yields better results than its counterparts. In particular, while cross-section specific models fail to provide accurate estimates for shear stress or velocity for other cross sections, the proposed model provides satisfactory results for all channel shapes. The better performance of the recommended approach can be attributed to the joint modeling of the shear stress and the velocity which is realized by capturing the correlation between these parameters in terms of a low rank output mixing matrix which enhances the prediction performance of the approach.(c) 2023 International Research and Training Centre on Erosion and Sedimentation/the World Association for Sedimentation and Erosion Research. Published by Elsevier B.V. All rights reserved.Environmental Sciences || Water Resource
Assessing Supply Chain Innovations for Building Resilient Food Supply Chains: An Emerging Economy Perspective
No full textFood waste reduction and security are the main concerns of agri-food supply chains, as more than thirty-three percent of global food production is wasted or lost due to mismanagement. The ongoing challenges, including resource scarcity, climate change, waste generation, etc., need immediate actions from stakeholders to develop resilient food supply chains. Previous studies explored food supply chains and their challenges, barriers, enablers, etc. Still, there needs to be more literature on the innovations in supply chains that can build resilient food chains to last long and compete in the post-pandemic scenario. Thus, studies are also required to explore supply chain innovations for the food sector. The current research employed a stepwise weight assessment ratio analysis (SWARA) to assess the supply chain innovations that can develop resilient food supply chains. This study is a pioneer in using the SWARA application to evaluate supply chain innovation and identify the most preferred alternatives. The results from the SWARA show that 'Business strategy innovations' are the most significant innovations that can bring resiliency to the food supply chains, followed by 'Technological innovations.' The study provides insights for decision makers to understand the significant supply chain innovations to attain resilience in food chains and help the industry to survive and sustain in the long run.Green & Sustainable Science & Technology || Environmental Sciences || Environmental Studie
READING ANKARA APARTMENT BALCONY BALUSTRADES (1950-75) AS MATERIAL CULTURE AND THEIR DIGITAL DOCUMENTATION
No full textThis paper considers the underexplored potential of wrought iron balcony balustrades as material culture, providing significant clues about a design community of a certain time and society at large. Exploring the wrought iron balcony balustrades of apartment buildings constructed in Ankara between 1950 and 1975, the study potentially contributes to widening the scope of the field of modern architectural culture in Turkey, while underscoring the significance of documenting and preserving these items as material evidence of this culture. Data on balcony balustrades were obtained through a scientific research project focused on 1,850 apartment buildings in Ankara's cankaya District. In particular, the study analyzes the balustrades' authenticity and technological aspect, and their role in shedding light on the relationships among various actors of the construction process. To provide a broader perspective, the study situates the issue within the wider context by conducting a literature review on material culture and the preservation of modern architectural heritage. Furthermore, the research incorporates an analysis of data from semi -structured interviews and an extensive collection of fieldwork photographs. The study concludes with a proposal for digital documentation methods to allow further light to be shed on the period and to preserve their memory, through a multi-layered reading of wrought iron balcony balustrades.Architectur
TRANSIENCE AND THE MODERN TURKISH INTERIOR
No full textDespite the expansion of research in modern interiors around the world and a more inclusive dialogue with regards to geography, ultimately, the field is still lacking theory and methods derived from its own specific needs rather than being adapted from architectural research, and a focus on its transient nature that is likely to lead to more impactful research and preservation results. Modern Turkish interiors research have also expanded greatly with individual, as well as projects or research groups like docomomo_tr interiors and DATUMM (Documenting and Archiving Modern Turkish Furniture) that create awareness through various forms of scholarly (documentaries, archival work) and popular (public exhibitions, popular books and magazines, newspaper pieces, and films) interiors research and several struggles are common worldwide, socio-cultural and economic reasons result in a faster pace in Turkey, creating an urgency to implement innovative methods and approaches fitting contemporary prerequisites of the field.Ar
Real-Time Cyberattack Detection with Offline and Online Learning
No full textThis paper presents several novel algorithms for real-time cyberattack detection using the Auto-Associative Deep Random Neural Network. Some of these algorithms require offline learning, while others allow the algorithm to learn during its normal operation while it is also testing the flow of incoming traffic to detect possible attacks. Most of the methods we present are designed to be used at a single node, while one specific method collects data from multiple network ports to detect and monitor the spread of a Botnet. The evaluation of the accuracy of all these methods is carried out with real attack traces. The novel methods presented here are compared with other state-of-the-art approaches, showing that they offer better or equal performance, with lower learning times and shorter detection times, as compared to the existing state-of-the-art approaches.Engineering, Electrical & Electronic || Telecommunication
When does intellectual capital enhance innovation capability? A three-way interaction test
No full textPurposeIn the current study based on the resource-based view (RBV), a three-way interaction model tests the relationships among human and social capital resources, innovation orientation (IO) and innovation capability in the context of new ventures.Design/methodology/approachHierarchical linear regression modeling presents the linear relations at two decision layers of start-ups, their founders and managers. Data is collected and analyzed from 233 new ventures in Turkey.FindingsFindings of the two and three-way interaction analyses indicate a positive relationship between human capital and innovation capability when social capital and IO are high || however, the relation turns off when low.Research limitations/implicationsThe study extends the previous works on the proposed link between intellectual capital (IC) resources and innovation, by confirming the moderating role of social capital and IO on the positive association between human capital resources and innovation capability.Practical implicationsThe results show that for start-up companies, the co-existence of strong social capital and the strategic orientation towards innovation is required for the effective utilization of human capital for generating innovation capability within the organization. Thus, this study highlights the importance of networks, alliances and social relationships, together with the unification of strategic thinking, organizational learning and a culture of innovation for attaining innovation goals, which are crucial for the survival and success of these units.Originality/valueThis study presents the first model in the literature which examines the moderating effects of IO and social capital on the human capital-innovation capability relationship.Business || Managemen
Air quality management using genetic algorithm based heuristic fuzzy time series model
No full textPurposeThe purpose of this paper is to provide a better method for quality management to maintain an essential level of quality in different fields like product quality, service quality, air quality, etc.Design/methodology/approachIn this paper, a hybrid adaptive time-variant fuzzy time series (FTS) model with genetic algorithm (GA) has been applied to predict the air pollution index. Fuzzification of data is optimized by GAs. Heuristic value selection algorithm is used for selecting the window size. Two algorithms are proposed for forecasting. First algorithm is used in training phase to compute forecasted values according to the heuristic value selection algorithm. Thus, obtained sequence of heuristics is used for second algorithm in which forecasted values are selected with the help of defined rules.FindingsThe proposed model is able to predict AQI more accurately when an appropriate heuristic value is chosen for the FTS model. It is tested and evaluated on real time air pollution data of two popular tourism cities of India. In the experimental results, it is observed that the proposed model performs better than the existing models.Practical implicationsThe management and prediction of air quality have become essential in our day-to-day life because air quality affects not only the health of human beings but also the health of monuments. This research predicts the air quality index (AQI) of a place.Originality/valueThe proposed method is an improved version of the adaptive time-variant FTS model. Further, a nature-inspired algorithm has been integrated for the selection and optimization of fuzzy intervals.Managemen