Web of Science ve Scopus Atıf Dizinlerindeki Yayınlar

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https://hdl.handle.net/11363/41

Web of Science ve Scopus Atıf Dizinlerindeki Yayınlar / Publications in Web of Science and Scopus Citation Indexes

Listeleniyor 1 - 20 / 386

PAFWF-EEGC Net: parallel adaptive feature weight fusion based on EEG-dynamic characteristics using channels neural network for driver drowsiness detection
(SPRINGER LONDON LTD, 236 GRAYS INN RD, 6TH FLOOR, LONDON WC1X 8HL, ENGLAND, 2025) Abdulwahhab, Ali Hussein; Myderrizi, Indrit; Yurdakul, Muhammet Mustafa
Drowsy driving is considered one of the most dangerous causes of road accidents and deaths worldwide. Drivers’ concentration is directly affected by fatigue, which affects their reaction time, reducing their attention and decision-making ability on the road. This can often lead to dangerous situations. With the development of Human Computer Interface systems and the rise of intelligent transportation systems, examining the effects of driver fatigue has become more critical, and research aimed at reducing the risk of fatigue-related accidents has gained importance. For this purpose, this study proposes a Parallel Adaptive Feature Weight Fusion based on EEG-Dynamic Characteristics using Channels Neural Network (PAFWF-EEGC Net) to detect the driver drowsiness condition. Two signal processing techniques are used to extract EEG dynamic features: first, Continuous Wavelet Transform (CWT) to capture the spectral-temporal features by accurately estimating both time and frequency localizations, and second, Fast Fourier Transform (FFT)—Power Spectrum Density (PSD) to convert the signals from the time domain to the frequency domain and show the distribution of signal power over frequency. These extracted dynamic features are passed to Attention channels and Parallel Adaptive Feature Fusion to integrate the most relevant feature channels to detect mental state. Furthermore, three processing dataset scenarios and cross-validation techniques are used to validate the Net. The Net showed excellent performance through ninefold/3rd scenario by achieving 98% detection accuracy, and 84%, 88.75%, 93.8% average detection accuracy through 1st, 2nd, 3rd scenarios respectively
Design and Thermodynamic Analysis of Waste Heat-Driven Liquid Metal–Water Binary Vapor Power Plant Onboard Ship
(MDPI, ST ALBAN-ANLAGE 66, CH-4052 BASEL, SWITZERLAND, 2024) Kepekçi, Haydar İzzettin; Ezgi, Cüneyt
Day after day, stricter environmental regulations and rising operating costs and fuel prices are forcing the shipping industry to find more effective ways of designing and operating energyefficient ships. One of the ways to produce electricity efficiently is to create a waste heat-driven liquid metal–water binary vapor power plant. The liquid metal Rankine cycle systems could be considered topping cycles. Liquid metal binary cycles share characteristics like those of the steam Rankine power plants. They have the potential for high conversion efficiency, they will likely produce lower-cost power in plants of large capacity rather than small, and they will operate more efficiently at design capacity rather than at partial load. As a result, liquid metal topping cycles may find application primarily as base-load plants onboard ships. In this study, a waste heat-driven liquid metal–water binary vapor power plant onboard a ship is designed and thermodynamically analyzed. The waste heat onboard the vessel is the exhaust gas of the LM2500 marine gas turbine. Mercury and Cesium are selected as liquid metals in the topping cycle, while water is used in the bottoming cycle in binary power plants. Engineering Equation Solver (EES) software (V11.898) is used to perform analyses. For the turbine inlet temperature of 550 ◦C, while the total net work output of the binary cycle system is calculated to be 104.84 kJ/kg liquid metal and 1740.29 kJ/kg liquid metal for mercury and cesium, respectively, the efficiency of the binary cycle system is calculated to be 31.9% and 26.3% for mercury and cesium as liquid metal, respectively. This study shows that the binary cycle has a thermal efficiency of 26.32% and 31.91% for cesium and mercury, respectively, depending on liquid metal condensing pressure, and a binary cycle thermal efficiency of 25.9% and 30.9% for cesium and mercury, respectively, depending on liquid metal turbine inlet temperature, and these are possible with marine engine waste heat-driven liquid metal–water binary vapor cycles.
Thermodynamic Analysis of Marine Diesel Engine Exhaust Heat-Driven Organic and Inorganic Rankine Cycle Onboard Ships
(MDPI, ST ALBAN-ANLAGE 66, CH-4052 BASEL, SWITZERLAND, 2024) Ezgi, Cüneyt; Kepekçi, Haydar İzzettin
Due to increasing emissions and global warming, in parallel with the increasing world population and energy needs, IMO has introduced severe rules for ships. Energy efficiency on ships can be achieved using the organic and inorganic Rankine cycle (RC) driven by exhaust heat from marine diesel engines. In this study, toluene, R600, isopentane, and n-hexane as dry fluids; R717 and R718 as wet fluids; and R123, R142b, R600a, R245fa, and R141b as isentropic fluids are selected as the working fluid because they are commonly used refrigerants, with favorable thermal properties, zero ODP, low GWP and are good contenders for this application. The cycle and exergy efficiencies, net power, and irreversibility of marine diesel engine exhaust-driven simple RC and RC with a recuperator are calculated. For dry fluids, the most efficient fluid at low turbine inlet temperatures is n-hexane at 39.75%, while at high turbine inlet temperatures, it is toluene at 41.20%. For isentropic fluids, the most efficient fluid at low turbine inlet temperatures is R123 with 23%, while at high turbine inlet temperatures it is R141b with 23%. As an inorganic fluid, R718 is one of the most suitable working fluids at high turbine inlet temperatures of 300 ◦C onboard ships with a safety group classification of A1, ODP of 0, and GWP100 of 0, with a cycle efficiency of 33%. This study contributes to significant improvements in fuel efficiency and reductions in greenhouse gas emissions, leading to more sustainable and cost-effective maritime operations.
Thermodynamic Analysis of a Marine Diesel Engine Waste Heat-Assisted Cogeneration Power Plant Modified with Regeneration Onboard a Ship
(MDPI, ST ALBAN-ANLAGE 66, CH-4052 BASEL, SWITZERLAND, 2024) İzzettin Kepekçi, Haydar; Ezgi, Cüneyt
The objective of this study is to perform a thermodynamic analysis on a marine diesel engine waste heat-assisted cogeneration power plant modified with regeneration onboard a ship. The proposed system utilizes the waste heat from the main engine jacket water and exhaust gases to generate electricity and heat, thereby reducing the fuel consumption and CO2 emissions. The methodology includes varying different turbine inlet pressures, extraction pressures, and fractions of steam extracted from the turbine to evaluate their effects on the efficiency, utilization factor, transformation energy equivalent factor, process heat rate, electrical power output, saved fuel flow rate, saved fuel cost, and reduced CO2 emissions. The analysis demonstrates that the proposed system can achieve an efficiency of 48.18% and utilization factor of 86.36%, savings of up to 57.325 kg/h in fuel, 65.606 USD/h in fuel costs, and 180.576 kg/h in CO2 emissions per unit mass flow rate through a steam turbine onboard a ship.
Gd ve Y İlave Edilmiş AZ31 Magnezyum alaşımına Ekstrüzyon ve Çok Yönlü Dövme Prosesinin Etkisi
(GAZI UNIV, CENTER CAMPUS TECHNOLOGY FAC B BLOCK EK BINA, 2ND FL, ANKARA 06500, Turkiye, 2025) Özdamar, Osman; Yetmez, Mehmet; Türen, Yunus; Kocaman, Engin; Özyiğit, Hamdi Alper
Bu çalışmada AZ31 Magnezyum alaşımına %0,5 ve %1 oranlarında Gadolinyum ile İtriyum Nadir Toprak Elementi kullanılarak yeni bir alaşım oluşturulmuştur. Oluşan bu alaşıma 375oC ekstrüzyon yapıldıktan sonra 400oC kapalı kalıpta çok yönlü dövme işlemi gerçekleştirilmiştir. Alaşım bileşenlerinin mikroyapıdaki değişime etkisi ve bunların mekanik özelliklere etkisi incelenmiştir. Çalışmada iri taneli bir yapıya sahip AZ31 döküm alaşımına ilave edilen nadir toprak elementleri ve uygulanan mekanik işlemlerin mikroyapıda etkili olduğu tespit edilmiştir. Alaşımına ilave edilen Gd ve Y’un mikroyapıda (Mg,Al)3Gd ve Mg24Y5 gibi intermetalik fazların oluşumunu teşvik ederken tane boyutunda önemli bir azalmaya neden olmuştur. Alaşıma kütlece %0.5 Gd ve %0.5Y Nadir Toprak Elementlerinin ilavesiyle elde edilen numunelerin sertlik, akma ve çekme mukavemetlerinin diğer döküm ve %1Gd ve %1Y ilavesiyle elde edilen değerlerden daha yüksek olduğu belirlenmiştir. Öte yandan döküm AZ31 alaşımına uygulanan mekanik işlemlerin tane boyutunu azalttığı ve mekanik özellikleri artırdığı tespit edilmiştir.
Developing machine learning‑based ground motion models to predict peak ground velocity in Turkiye
(SPRINGER, VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS, 2024) Kuran, Fahrettin; Tanırcan, Gülüm; Pashaei, Elham
This paper introduces machine learningbased Turkiye-specifc ground motion models for the geometric mean horizontal component of peak ground velocity (PGV). PGV is a signifcant intensity metric to measure and diagnose potential earthquake damage in structures. Reliable prediction of PGV is of essential importance in precise calculations of seismic hazard. The efciencies, reliabilities, and capabilities of various machine learning algorithms, including Random Forest, Support Vector Machine, Linear Regression, Artifcial Neural Network, Gradient Boosting, and Bayesian Ridge Regression, are evaluated and compared. The most recently compiled Turkish strong motion database, which consists of over 950 earthquakes occurring from 1983 to 2023, is used for shaping the models’ ability to learn and make accurate predictions. Three feature selection methodsLeast Absolute Shrinkage and Selection Operator, Recursive Feature Elimination, and Pearson’s Correlation- representing embedded, wrapper, and flter approaches, respectively, are applied to determine the most suitable estimator parameters to predict PGV. Residual analyses and statistical evaluation metrics are employed to measure the performance and efectiveness of the machine learning models. Among the algorithms applied, Gradient Boosting demonstrates exceptional success in predicting PGV, particularly when utilizing all estimator parameters (features) collectively. The Gradient Boosting model exhibits superior predictive capabilities compared to existing ground motion models. It is applicable to shallow crustal strike-slip and normal faulting earthquakes with moment magnitude ranging from 3.5 to 7.8 and Joyner and Boore distance up to 200 km.
A systematic risk assessment approach for urban roadside infrastructure assets
(TAYLOR & FRANCIS LTD, 2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND, 2024) Yurdabal Apak, Mustafa; Ergün, Murat; Özen, Halit; Yumrutaş, Halil İbrahim
Revealing potential risks and the influence of these risks on urban roadside vulnerable/risky zones has been a great deal for the last decades owing to increasing vehicular mobility. This study aimed to develop a risk assessment methodology for urban roadside infrastructure assets. In this context, seven risk parameters that are likely to affect hazardous aboveground assets installed on urban roadsides were determined, and weights of each parameter (order of importance) were presented based on expert surveys and literature information using the Analytic Hierarchy Process (AHP) method. Mathematical models were set up for each risk parameter using real field data, The American Association of State Highway and Transportation Officials (AASHTO), literature, related standards, and expert surveys by linear, nonlinear, and binary logistic regression analyses. Risk groups were created, and precautions were offered. The efficiency of the models was verified based on the 28 accident records and field observations in 172 assets. When considering the assets that undergo traffic accidents, 71% of the total assets are ranked in the critical and high-risk group. This ratio is consistent with the risk group definitions assigned in this study; thus, the model proposed is accurate and can be applied reliably. The verification process of the total risk model was sufficiently successful to be used in practice and can be generalized by considering the road and traffic characteristics, infrastructure facilities, and future requirements of the regions or countries that reflect similar historical and cultural concerns. Practitioners, governmental institutes, and researchers can apply this methodology to provide their own data with high transparency and reliability.
The impact of mental health disorders and job demands on the individual job performance of construction workers
(WILEY, 111 RIVER ST, HOBOKEN 07030-5774, NJ, 2024) Kazar, Gökhan; Rahmanzadeh, Pourya
Objectives: Understanding the impact of job demands and mental health disorders on individual job performance is crucial to achieving a more productive workforce and should be empirically investigated. Therefore, the main purpose of this study was to assess the impact of job demands and mental health disorders on individual job performance among construction workers. In addition, we examined the interaction effect between job demands and some demographic characteristics (income, marital status, experience, and area of residence) on the job performance of construction workers in 2 dimensions. Methods: For this purpose, a new conceptual model and 3 different hypotheses were introduced. A survey was designed and administered to 513 construction workers. Whereas the measurement items regarding demographic characteristics, job demands, and mental health disorders were addressed to construction workers, the last part related to job performance of construction workers was conducted with site managers of the workers to obtain more objective results. A structural equation modeling approach was adopted to assess the validity of the model and to test the hypotheses. Results: The results of this study show that whereas job demands have a significant and high impact on individual job performance, the effect of mental health disorders on job performance is significant at a moderate level. In addition, the demographic characteristics of marital status and area of residence have a significant interaction effect on job performance when combined with job demands. Conclusion: Providing individualized support systems, resources, and opportunities for construction workers can help mitigate the negative effects of excessive demands and mental disorders on labor productivity.
Sustainability performance of food supply chains with internal and external evaluation perspectives
(OXFORD UNIV PRESS, GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND, 2024) Gürül, Binnur; Yılmaz, Dilek; Büyüksaatçı Kiriş, Sinem
The challenges of food security, water use, energy consumption and the growing global demand for food raise the importance of ensuring sustainability of the food supply chains (FSCs). Studies in relevant literature discuss the sustainability performances of FSCs generally without distinguishing between the internal and external stakeholders’ concerns or clarifying the existence of greenwashing or bluewashing attempts, jeopardizing true sustainability. This is why modelling towards some holistic treatment of the problem that satisfies those concerns is required. This paper proposes a framework to evaluate the true sustainability performance of FSCs by considering triple bottom line indicators, i.e. economic, environmental and social. In light of the proposed framework, two models have been developed, one calculating the internal and the other an external sustainability score. The presented models can handle interval or ordinal qualitative and quantitative indicators concurrently while considering desirable and undesirable factors. These novel models have been implemented on data from 50 FSCs in Istanbul, using a two-stage imprecise data envelopment analysis with a special multiplier. To facilitate visualization of true sustainability assessment, an internal–external sustainability performance matrix is proposed. Results reveal that the internal sustainability performance of the focal FSCs is better than the external one. The economic dimension predominates in Turkish FSCs’ internal sustainability performance, while the environmental and social dimensions predominate in the external sustainability performance of the FSCs.
Transient analysis of functionally graded axisymmetric plates via finite element method in the Laplace domain
(TAYLOR & FRANCIS INC, 530 WALNUT STREET, STE 850, PHILADELPHIA, PA 19106, 2024) Doori, Silda Ghazi Mohammed; Noori, Ahmad Reshad
The principal goal of this research article is to examine the forced vibration of Functionally Graded Material (FGM) axisymmetric plates with the aid of the finite element method in the Laplace space. The material properties are assumed to be isotropic, linear viscoelastic, or elastic and vary continuously in the direction of the thickness of the plate. The governing equations of motion are transferred to the Laplace domain and solved for a set of Laplace parameters. Then, a modified Durbin’s inverse Laplace method is employed to retransfer the obtained results back to the time domain. A convergence analysis is conducted to optimize the number of Laplace parameters and time steps. An 8-node quadratic quadrilateral element featuring two degrees of freedom per node is employed to generate the model of the axisymmetric plates. Different loads such as step load, square wave, and sawtooth wave loads are used to observe the impact of load type on the transient response of FGM plates. In viscoelastic analysis, the Kelvin damping model is preferred, and the effect of the damping ratio is investigated. The obtained results are validated with the aid of the available literature and the accuracy of the suggested model is confirmed. It is carried out that the material variation significantly affects the dynamic behavior of the plates, for instance as the material coefficient increases, displacement amplitudes decrease, and periods increase. The novelty of this paper is the employment of the finite element method together with Laplace transformation for addressing the present class of problems for the first time.
Efficient Roof Selection in Rainwater Harvesting: Hybrid Multi-criteria and Experimental Approach
(SPRINGER, VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS, 2024) Hamidi, Muhammed Nimet; Shitreh, Shayan; Cengiz, Ali Izzet; Özçelik, Kadir; Eryıldız Yesir, Bahriye; Ekmekcioğlu, Ömer; Halat, Oğuzhan Murat; Demirel, Mehmet Cuneyd; Canberk, Berk; Koyuncu, İsmail; Işık, Onur; Güven, Hüseyin; Özgün, Hale; Erşahin, Mustafa Evren
This study aimed to investigate the effects of different roof configurations on the quality of harvested rainwater (HRW) for sustainable irrigation in agriculture. Three roofing materials (i.e. shingle, galvanized metal, and clay tile) and three roof pitch angles (i.e. 5°, 30°, and 42°) were used at pilot-scale. HRW was characterized in order to determine the roof type and roof slope effect on the HRW quality. HRW from galvanized metal roofs was of higher quality in terms of turbidity and pathogen microorganisms. HRW from shingle and clay tile roofs was treated with a sequential ultrafiltration (UF) membrane and ultraviolet (UV) disinfection system to meet the European Union (EU) water reuse standards for irrigation. The decision-making mechanism was used to select the most appropriate roof configuration. The results showed the significance of financial (21.89%) and environmental (19.75%) aspects. Also, the Escherichia coli (E.coli) content (7%) is the most determinant factor in HRW, followed by the operational cost (6.78%), and reduced runoff (5.73%). Among the roof configurations, galvanized metal roofs, specifically the metal roof with 5°, outperformed others due to their structural, technical, and environmental advances.
Exploring dielectric and electrical characteristics in Sr0.5Ba0.5SnxFe12-xO19/CoFe2O4 nanocomposites
(ELSEVIER SCI LTD, 125 London Wall, London EC2Y 5AS, ENGLAND, 2024) Almessiere, Munirah Abdullah; Ünal, Bayram; Baykal, Abdulhadi; Demir Korkmaz, Ayşe; Gondal, Mohammed Ashraf; Slimani, Yassine; Kahraman, Süleyman; Güngüneş, Hakan
This study examined the morphological, structural, electrical, and dielectric characteristics of hard-soft (H-S) Sr0.5Ba0.5SnxFe12-xO19/CoFe2O4 (x ≤ 0.10) ferrite nanocomposites (NCs), created using one-pot sol-gel combustion route. This study systematically investigated the electrical/dielectric features of H-S Sr0.5Ba0.5SnxFe12- xO19/CoFe2O4 NCs where x is within the range of 0.00 ≤ x ≤ 0.10. The examination realizes frequencies that reach 3.0 MHz, conducted within 20 ◦C–120 ◦C. A detailed analysis was performed to investigate various conduction mechanisms linked with dielectric constant, dissipation factor, AC/DC conductivity, loss of dielectric capacity, and real/imaginary modulus, which were explored across the entire range of Sn ion substitution ratios. Observations reveal that the conductivity variations adhere to power law dynamics concerning frequency, predominantly influenced by the Sn ion substitution ratios within the NCs. Furthermore, the frequency dependency of the dielectric coefficient across all NCs substantiates the common propagation of dielectric behavior, prominently contingent upon the substitution ratio of "x". Notably, the majority of dielectric parameters observed in H-S Sr0.5Ba0.5SnxFe12-xO19/CoFe2O4 (x ≤ 0.10) NCs are attributable to grain-to-grain boundaries, elucidated by conduction mechanisms similar to those observed in most compositional ferrites, explicable through Koop’s model.
Project characteristics-based predicting the likelihood of occupational accidents in public school maintenances using a topological approach
(ELSEVIER, RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS, 2025) Yiğit, Uğur; Kazar, Gökhan
Occupational accidents are common in construction projects. Although several previous studies have focused on this complex issue from different perspectives, such as predicting accidents for the general construction process, few studies have focused on the impact of project characteristics on the likelihood of accidents in building maintenance projects. Artificial intelligence-based predictive models for workplace accidents typically use readymade algorithms or traditional methods like trial and error. Therefore, the main objective of this study is to predict the likelihood of occupational accidents in building maintenance projects by following a new feature selection process based on the topological approach. The information on the 1807 public school maintenance project was included in this study to test the proposed mathematical approach. Commonly used 7 different machine learning algorithms and a combination of these algorithms called a hybrid model was selected to apply the topological approach to the feature selection process. The results show that 5 out of 7 algorithms such as Stochastic Gradient Boosting (SGB), Extreme Gradient Boosting (EGB), Linear Discriminant Analysis (LDA), Gaussian Naive Bayes (GNB), and Hybrid (HYB) models show better performance after applying the topological technique. The main predictors of the likelihood of workplace accidents in these algorithms are site delivery (T2), cost breakdown ratio (F1), total duration (T1), and contractor size (P1). Using this approach, construction professionals can develop and implement more effective AI-based proactive safety management systems for maintenance projects.
Enhancing Najran’s sustainable smart city development in the face of urbanization challenges in Saudi- Arabia
(TAYLOR & FRANCIS LTD, 2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND, 2024) Alotaibi, Badr Saad; Elnaklah, Rana; Agboola, Oluwagbemiga Paul; Abuhussain, Mohammed Awad; Tunay, Mustafa; Dodo, Yakubu Aminu; Maghrabi, Ammar; Alyami, Mana
This research offers valuable perspectives on the nexus between urbanization and the smart environment within the Najran city, Saudi Arabian context. Najran City, with its diverse districts and evolving urban landscape, is at the forefront of adopting advanced technologies and participatory governance models to create a resilient, environmentally conscious, and sustainable urban environment, likewise positioning itself as a model of smart urban development but is also fostering an innovation-driven community equipped to address the difficulties and exploit the prospects given by the 21st century. The study systematically analyzes the multifaceted factors of smart city variables in Saudi Arabia and their direct impact on urban sustainability through extensive quantitative investigations. This study reveals the positive correlations between smart city attributes, on the attainment of urban sustainability. In order words, the smart city’s attributes such as IoT (Internet of Things) devices, smart infrastructure, and data-driven solutions are linked to the creation of a resilient urban environment in the face of urbanization and sustainability challenges. On the other hand, the study noted that the integration of smart technologies might lead to unintended consequences in urban planning. For example, an overemphasis on technology may overshadow human-centric approaches, which might potentially affect the community well-being and social cohesion. Study’s insights provide policymakers, urban planners, and players with an indepth knowledge of the pathways to harness smart city attributes for sustainable Najran urban development. The implications of this research extend beyond the borders of Saudi Arabia, serving as a valuable reference for regions worldwide grappling with similar urbanization and sustainability challenges in the 21st century. By harnessing the potential of smart cities, Saudi Arabia and other nations can pave the way for greener, more resilient urban futures.
Carbon dioxide absorption using monoethanolamine, piperazine and n-metil-2-pirolidon solvents under counter current regime in packed column reactor
(ELSEVIER SCI LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND, 2024) Gül, Ayşe; Barış, Mesut; Tezcan Ün, Ümran
In this research the carbon dioxide absorption using Monoethanolamine (MEA), Piperazine (PZ) and N-Metil-2- pirolidon (NMP) solvents and their different blends (MEA/NMP, PZ/NMP, MEA/PZ) in packed column reactor filled with Raschig rings was investigated and compared for efficient carbon dioxide absorption. The process was followed in a countercurrent regime under a liquid flow rate of 200 mL/min, gas flow rate of 2.5 L/min, and CO2 concentration of 50,000 ppm. Carbon dioxide removal efficiency (%), absorption capacity (mol CO2/mol solvent), overall mass transfer coefficient (1/min) and absorption rate (mol/l.s) were monitored. The highest obtained values for carbon dioxide removal efficiency, absorption capacity and overall mass transfer coefficient were 57.5%, 0.148 mol CO2/mol solvent and 2.178 min? 1 respectivelly when 0.03 M MEA/0.07 M PZ in a hybrid system was used. It was concluded that PZ blends with MEA were successful absorbent as the organic physical solvent whereas NMP didn’t show improving effect in blends with MEA on the absorption efficiency.
Effect of Minor Sb Additions on Thermal Properties, Microstructure and Microhardness of Sn–Ag–Cu High-Temperature Solder Alloys
(MAIK NAUKA/INTERPERIODICA/SPRINGER 233 SPRING ST, NEW YORK, NY 10013-1578, 2023) Aksöz, Sezen; Öcal, Fadimana; Ata Esener, Pınar; Öztürk, Esra; Maraşlı, Necmettin
In the present study, changes in thermal properties, microstructure and microhardness were investigated when 0.5, 1, 1.5 wt % Sb were added to Sn–1 wt % Ag–0.5 wt % Cu (SAC105) solder alloy system. The addition of Sb caused a significant improvement in microhardness while decreasing the melting temperature range, thermal conductivity and electrical conductivity. Addition of 0.5, 1, 1.5 wt % Sb to SAC105 alloy system decreased the thermal conductivity by 48% and electrical conductivity by 27%. The addition of Sb at the same rate increased the microhardness by 27%.
Performance Characterization of Plywood Panels Bonded With Melamine-Urea-Formaldehyde Resin and Cellulose Nanofibril/Borax As An Additive
(UNIV BIO-BIO, DEPT WOOD ENGINEERING, AVENIDA COLLAO 1202, CASILLA 5-C, CONCEPCION 4081112, CHILE, 2024) Yıldırım, Mert; Candan, Zeki; Akbulut, Turgay; Gardner, Douglas J.; Shaler, Stephen M.
In this study, different loading levels of cellulose nanofibril and borax were added as reinforcement in melamine-urea-formaldehyde adhesive to enhance the performance properties of plywood panels as engineered wood composites. Physical properties (density, thickness swelling, water absorption, and moisture content), mechanical properties (modulus of rupture, modulus of elasticity, and bonding strength), and formaldehyde content were tested using relevant standards. The results showed that cellulose nanofibril and borax had a synergistic effect, resulting in improved physico-mechanical properties. The best results were obtained by combining 3 % cellulose nanofibril and borax. It was determined that the combination of cellulose nanofibril and borax reinforcement resulted in a significant improvement of around 15 % in the thickness swelling, water absorption, and moisture content of plywood panels. The combination of cellulose nanofibril and borax reinforcing resulted in a significant increase of around 26 % in the modulus of rupture and modulus of elasticity of plywood panels, with a bonding strength of around 47 %. The reinforcement technique did result in a 34 % decrease in free formaldehyde content. As a consequence, cellulose nanofibril and borax can be used as effective additives in the production of plywood panels to enhance their performance properties.
Unveiling the Impact of Urban Green Landscape on Quality of Life in Kaduna, Nigeria: Residents' Perceptions and Sustainable Strategies
(Alanya Üniversitesi, 2024) Ojobo, Henry; Agboola, Oluwagbemiga Paul; Shamang, Kasham Jummai
This study investigates the influence of urban green landscapes on the Quality of Life (QoL) in Kaduna Metropolis, Nigeria, focusing on residents' perceptions and sustainable urban development strategies. Conducted from May to July 2023, the quantitative research surveyed 377 residents using a questionnaire. Statistical analysis, including correlation and t-tests, was performed using SPSS version 23. Findings reveal a positive perception of urban green spaces, significantly contributing to residents' QoL. Key results include high satisfaction with green areas enhancing environmental beauty (Mean=4.88, SD=0.90) and providing recreational appeal (Mean=4.45, SD=0.95). Additionally, these areas significantly impact perceived value (Mean=4.78, SD=0.93), prestige (Mean=4.92, SD=8.18), and attachment to the environment (Mean=4.71, SD=0.831). Residents with accessible and functional green spaces express higher satisfaction levels (Cronbach’s Alpha > 0.9). The study underscores the importance of urban greenery in improving urban living conditions and offers strategic recommendations for sustainable urban planning. Addressing a gap in literature, this research provides empirical insights into residents' perspectives within Kaduna Metropolis, contributing to academic discourse and practical urban development approaches.
Gamma-Ray Irradiation Effect on Mechanical and Dielectric Properties of Volcanic Basalt Mineral Reinforced Low Density Polyethylene Films
(OFICYNA WYDAWNICZA POLITECHNIKI WROCLAWSKIEJ, WYBRZEZE WYSPIANSKIEGO 27, 50-370 WROCLAW, POLAND, 2017) Kılıç, Mehmet; Karabul, Yaşar; Alkan, Ümit; Yağcı, Özlem; Okutan, Murat; Okutan, Mustafa; İçelli, Orhan
The aim of the work is to study the mechanical and dielectric properties of low density polyethylene (LDPE) that can be modified by basalt mineral under low dose gamma irradiation. The composite films are prepared by a hot pressing method (15 MPa, 418 K, for about 10 min), and then irradiated by Co-60 gamma-rays in the dose range varied between 6 and 24 gray (Gy). Mechanical and dielectric properties of these samples are examined by means of stress-strain measurements and dielectric spectroscopy in the frequency range of 100 Hz –15 MHz at the room temperature. Experimental measurements evidence that the mechanical properties of LDPE were weakened by basalt additives and radiation. The tensile strength of 0.5 wt.% basalt additivity, which has an optimum value increased by 30 percent when compared to pure LDPE without radiation. When LDPE and LDPE/basalt composites were radiated between 6 to 24 Gy, the mechanical properties of both samples decreased at almost the same rate. The LDPE/ 0.5wt.% basalt composite sample without gamma-irradiation was the one with the highest mechanical strength. In the absence of radiation, the low (static) frequency real part of dielectric constant is increased with basalt additives. The dielectric strength reached a maximum value up to 20.0 wt.% basalt additive at 6 Gy dose. However, the polymeric structure of the sample was deteriorated.
Fractal analysis of MR images in patients with chiari malformation: The importance of preprocessing
(ELSEVIER SCI LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND, 2017) Akar, Engin; Kara, Sadık; Akdemir, Hidayet; Kırış, Adem
As a popular method to meathe complexity of images and generally signals, FD analyses have been used in neuroimaging studies to evaluate the morphological complexity of brain structures. The aim of this study is to perform an FD-based complexity analyses of cerebellar tissues, such as cerebellar white matter (WM), cerebellar gray matter (GM) and cerebrospinal fluid (CSF) spaces around the cerebellum, on magnetic resonance (MR) images of Chiari Malformation type-I (CM-I) patients and healthy controls. Besides, to determine the noise effects on complexity of sub cerebellar structures, two common nonlinear noise filters, median filter and bilateral filter, were applied to MR images and their performances were compared. Data of fourteen CM-I patients and sixteen normal subjects were used in this study. First, noise variance was estimated using a method based on skewness of the magnitude data. Second, as a preprocessing step, median and bilateral filters were applied on MR data separately to create different series of images for each filter. After the preprocessing, filtered brain images were segmented into three different tissues including WM, GM and CSF. Last, a 3D box-counting method was applied on segmented images to estimate the corresponding FD values. Our results showed that, while GM FD values was not significantly different between patients and controls (p = 0.051) in median filtering case, GM FD values in patients were found to be significantly lower than those in controls (p = 0.007) in bilateral filtering case. Additionally, in both cases, WM FD values in patients were found to be significantly lower than those in controls; however, this difference was more evident in bilateral filtering case (p = 0.0003) than that in median filtering case (p = 0.013). These outcomes indicated that bilateral filter was found to be more successful in discriminating CM-I patients from controls in cerebellar complexity analyses. In conclusion, results of this study revealed that noise removal is an important preprocessing step for a more successful analysis of digital images and bilateral filter is an effective filtering method for segmentation accuracy and FD analysis performance.

Güncel Gönderiler