This study conducts a comprehensive analysis of the free vibration characteristics of honeycomb sandwich cylindrical shells reinforced with graphene nanoplatelets (GNPs). The shells are modeled with a hexagonal honeyc...
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This study conducts a comprehensive analysis of the free vibration characteristics of honeycomb sandwich cylindrical shells reinforced with graphene nanoplatelets (GNPs). The shells are modeled with a hexagonal honeycomb core, which not only provides a lightweight structure but also enhances the stiffness and dynamic stability. This core design is ideal for high-performance applications such as aerospace and light transport equipment. In addition, the incorporation of graphene nanoplatelet/polymer coatings further improves the structural stiffness, making these shells suitable for demanding environments where both strength and lightweight properties are critical. In the theoretical model, the refined trigonometric shear deformation theory (RTSDT) is applied to accurately represent both bending and shear deformations, capturing the complex behavior of honeycomb sandwich cylindrical shells without requiring shear correction factors. Various parameters, including axial and circumferential wave numbers, as well as geometry and material properties, are examined to assess their impact on natural frequencies. Comparisons with existing literature validate the theoretical models, demonstrating strong agreement with previous results. The analysis reveals that the fundamental natural frequency and other natural frequencies are significantly affected by the inclusion of GNPs and variations in sandwich cylindrical shell geometry. The findings underscore the effectiveness of the RTSDT in modeling these complex sandwich structures.
Research on old city patterns in the world has become an area for archeologists. Historians and archeologists in Java, Indonesia, discovered a city center with a North-South axis, alun-alun (open space) surrounding by...
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Research on old city patterns in the world has become an area for archeologists. Historians and archeologists in Java, Indonesia, discovered a city center with a North-South axis, alun-alun (open space) surrounding by the government and religious building. This concept continued from the Majapahit Kingdom (12-15 centuries) to the Islamic Sultanate (15th century) and stopped in the Islamic Mataram Sultanate (17th century). However, Semarang City, as a city subordinate to the Islamic sultanate, has the same city center pattern, but the North-South axis is blurred. This research used data from several old maps, sketch drawings, photographs, and traditional city patterns in Java to find out the whole model of old Semarang City. Semarang also had a North-South axis that was no longer visible due to constructing the great pos road, railroad line, and city development. The sustainability of traditional city patterns in Java has not stopped in Mataram Islam sultanate city. This pattern also applied to the city as a sub-ordinate Islamic sultanate. The sustainability of the urban pattern, starting from the influencing power, shifted to the spreading of religion. The traditional city pattern can be a reference in city design based on the city's history.
Open-plan offices, which are becoming increasingly popular in the 21st century, are the subject of debate due to the effects of their physical environment on productivity. The physical environment in open-plan offices...
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Open-plan offices, which are becoming increasingly popular in the 21st century, are the subject of debate due to the effects of their physical environment on productivity. The physical environment in open-plan offices can significantly affect user productivity and this effect can be positive or negative depending on various factors. As the number of employees in the office environment increases, problems that may occur in the ventilation of the environment or failure to provide the targeted comfort;may cause problems such as illness or dissatisfaction on users. These problems are reflected in the business as job loss or productivity decline. In today's competitive business environment, the approach of businesses to provide a healthy and comfortable environment to their employees in order to prevent job loss and increase productivity affects the choice of real estate. Based on the results of the study, the relationship between comfort and productivity in open office spaces can be conceptualized. When this hypothesis is expressed in a theoretical approach, a relationship is constructed as shown below (Figure A).
This study discusses acoustic dissipation, which contributes to inaccuracies in impedance tube measurements. To improve the accuracy of these measurements, this paper introduces a transfer function model that integrat...
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This study discusses acoustic dissipation, which contributes to inaccuracies in impedance tube measurements. To improve the accuracy of these measurements, this paper introduces a transfer function model that integrates diverse dissipation prediction models. Bayesian inference is used to estimate the important parameters included in these models, describing dissipation originating from various mechanisms, sound speed, and microphone positions. By using experimental measurements and considering a hypothetical air layer in front of a rigid termination as the material under test, Bayesian parameter estimation allows a substantial enhancement in characterization accuracy by incorporating the dissipation and sound speed estimates. This approach effectively minimizes residual absorption coefficients attributed to both boundary-layer effects and air medium relaxation. The incorporation of dissipation models leads to a substantial reduction (to 1%) in residual absorption coefficients. Moreover, the use of accurately estimated parameters further enhances the accuracy of actual tube measurements of materials using the two-microphone transfer function method. (c) 2024 Acoustical Society of America.
In light of escalating concerns surrounding contemporary environmental challenges, the imperative to promote sustainable practices for product disposal, including product reuse and product life extension, has gained s...
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In light of escalating concerns surrounding contemporary environmental challenges, the imperative to promote sustainable practices for product disposal, including product reuse and product life extension, has gained significant momentum. Upcycling is a promising avenue for achieving sustainability, which involves reevaluating discarded materials and repurposing them into valuable commodities. This comprehensive review explores the multifaceted benefits of a carefully chosen selection of upcycled products, specifically focusing on their application within the construction sector. The primary objective of this study is to establish a comprehensive framework consisting of three fundamental dimensions-namely, economic, ecological, and social-to serve as evaluative criteria for the production of upcycled products. The insights from this research offer guidance and recommendations for academic researchers, industry practitioners, and policymakers in promoting consumer engagement with upcycled products. Ultimately, organizations can leverage these established Upcycled Product criteria within their design strategies, optimizing such products' social, economic, and ecological value.
On a global scale, urban areas struggle with various environmental, social, and economic problems due to rapidly growing populations and rapid urbanization processes. In this context, nature-based solutions (NbS) offe...
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On a global scale, urban areas struggle with various environmental, social, and economic problems due to rapidly growing populations and rapid urbanization processes. In this context, nature-based solutions (NbS) offer an important perspective for the sustainability and livability of urban areas alongside traditional infrastructure systems. This study aims to investigate how NbS can address environmental issues in urban areas, tackle various urban challenges using a multi-perspective approach, and examine the potential and applicability of NbS approaches in solving problems in urban areas. With emphasizing the importance of NbS and an ecological perspective in solving problems in urban areas and presenting recommendations and challenges that can be applied in urban planning and management processes, the current study also encourages the adoption of nature-compatible approaches to contribute to the sustainability of urban areas and ensure a livable environment for future generations.
Accurate assessment of the combined impacts of climate change and Urban Heat Island (UHI) on the energy performance of building prototypes is imperative to support decision-making towards long-term resilient design so...
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Accurate assessment of the combined impacts of climate change and Urban Heat Island (UHI) on the energy performance of building prototypes is imperative to support decision-making towards long-term resilient design solutions for heat mitigation. Recent literature highlighted the importance of integrating multiscale climate models into Building Energy Simulations (BES) workflows to accurately evaluate UHI and future scenarios, especially for climates susceptible to indoor overheating. However, discussion relative to the uncertainties when using projections on BES is still limited on account of the scarcity of readily available weather files for some cities and the impracticalities that arise from conducting several simulations. This study aims to address these issues by investigating the resilience of a social housing prototype with optimized envelope and heat mitigation strategies for the hot and humid Belem, Brazil under distinct UHI conditions considering future uncertainties. Thermal autonomy and cooling loads were evaluated for 2020, 2050 and 2080. Future weather uncertainties were assessed through comparison of dry-bulb temperatures between the projections generated by Climate Change World Weather Generator (CCWWG) and CORDEX project. Results showed a significant decrease in thermal autonomy despite optimization as the housing lower-floor units registered only 15 % of occupancy hours below the 30 degrees C threshold in 2050 considering UHI and 2.8 % in 2080 before UHI inclusion, in contrast to the 100 % observed for the unmodified weather file. Accordingly, high percentage increases in cooling loads between simulations emphasize the importance of comparing results of multiple weather files for thorough investigations of BES.
Machine learning models have become a potential alternative for building energy performance studies since they provide fast and reliable prediction results. However, decisions in the modeling process are sometimes mad...
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Machine learning models have become a potential alternative for building energy performance studies since they provide fast and reliable prediction results. However, decisions in the modeling process are sometimes made without knowing their possible impact on the results, which may lead to unstable process management. Therefore, this study aims to obtain a machine learning modeling process framework focusing on critical-decision subjects through a systematic review of the recent literature. Preferences of the current supervised modeling practices on process-related variables to have prediction models with high accuracy were analyzed in the studies using simulation data. In this paper, a general framework of the processes is presented through their steps and decision subjects. Regarding these steps, the frequency of the methods used, strategies followed against the limitations, common sources of concerns, and intertwined workflows are analyzed with their effects on prediction performance in terms of accuracy. In addition, correlations between process-related variables, i.e., decision subjects and model performance, are investigated to quantify the impacts. As a result, the most effective decision subjects on accuracy were observed as the machine learning algorithm to be used, input variables to be included, and the range of the sample size, respectively.
Designated as architect by Osman Hamdi, Alexander Vallaury designed the classical building of First Imperial Museum of Ottoman Empire (Muze-i Humayun - Istanbul Archaeological Museums - IAM), erected between 1891 and ...
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Designated as architect by Osman Hamdi, Alexander Vallaury designed the classical building of First Imperial Museum of Ottoman Empire (Muze-i Humayun - Istanbul Archaeological Museums - IAM), erected between 1891 and 1907 in three phases. The IAM building sprouted inside the land walls of Topkapi Palace, which was built in the acropolis of the ancient Greek city Byzantion, just across from the ruins of the Great Palace of Byzantine Empire. This building is in a core area, symbolizing the imperial power of Roman, Byzantine, and Ottoman eras. Unlike previous studies, which examined mostly the building's architectural history, this study focuses on the time before its construction. It investigates the understructure remains by utilizing the original drawings and correspondences in the Museum Archive, which were made during the construction of second and third phases of the building in 1899-1907 at the end of the Ottoman Period. Through this investigation, it reveals the reciprocal relationship between the superstructure of IAM and the Byzantine substructure for the first time in the literature. All these sources were used to create a holistic site restitution of the museum buildings, covering old and newfound remains.
A debris flow barrier is a structure used to prevent erosion caused by debris flow, and is typically installed in countries with mountainous areas, such as Korea. However, owing to earth pressure, several debris flow ...
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A debris flow barrier is a structure used to prevent erosion caused by debris flow, and is typically installed in countries with mountainous areas, such as Korea. However, owing to earth pressure, several debris flow barriers become damaged. Geofoam is a reinforcement material widely used in the design of debris flow barriers, not only in dams/retaining walls but also in bridges and landscaping. The purpose of this study was to examine the lateral earth pressure reduction effect of geofoam on debris flow barriers, and to find an optimized geofoam shape that satisfies specific conditions. In this study, the debris flow barrier, backfill, geofoam, and foundation were modeled using ABAQUS, a two-dimensional finite element method program. Models A-C were simulated and compared at backfill lengths of 10, 20, and 40 m. The debris flow barrier model was used at a mountain slope of 25 degrees. To determine the geofoam shape and analyze the stability coefficients for sliding and overturning, ten diverse scenarios were considered. According to the results, Scenario 10, with a reversed triangle shape of geofoam, was the most effective in all cases, which reduces the earth pressure significantly. In the case of Model C, a reversed triangle geofoam reinforcement reduces the lateral earth pressure on the backside of the structure by an average of 34.43%.
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