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Abstract
The immediate vicinity of buildings of different floors causes damages of the smoke and ventilation channels work of the low-rise buildings. This is dangerous for the resident's health and lives. To determine the impact of high-rise buildings on the operation of air channels of a nearby two-story building, experimental research has been carried out in a wind tunnel. Charts and analytical formulas have been designed for determining the buildings aerodynamic coefficients depending on wind directions and the channels height. An increase of the channel height results in an increase in static rarefaction in smoke and ventilation channels. Increasing rarefaction increases the efficiency of the natural ventilation system and ensures the residents health and life.
Abstract
Springs are the most basic mechanical elements used in transmission mechanisms. The rapid development of the computer and cellular industry has encouraged spring manufacturers to develop the industry to produce very small springs. Most computer-aided design programs for mechanical parts provide the possibility of designing these parts, as these programs include different types of decisions. All these decisions require coordinates for geometric data as well as metadata. The paper aims to develop software programs to design and analyze springs as one of the most significant mechanical elements used. This paper aims to develop a design software of a helical spring system, where this software is built using a computer program in the language of Visual Basic Version 5. When the user enters data into the system, the system will perform a series of complex calculations in the system, then provide a detailed report on all the engineering dimensions of the spring, and test its efficiency. The output of the software shows the required spring wire parameters. The software was tested with test data from the open literature, and the required wire spring parameters were obtained.
Abstract
Numerous studies have proven that digital development positively affects economic growth. This study aims to confirm or refute the positive impact of digital evolution on economic growth by applying the dimensions of the International Digital Economy and Society Index (I-DESI). The analysis refers to the period 2015–2020 of the European Union member states. The study's novelty is that the I-DESI index has yet to be used in research to investigate the relationship between the digital transition and GDP production. The present study, therefore, goes one step further than the previous typical DESI-GDP models. The research uses Pearson correlation and F-statistic analysis to show the relationship between the variables. The study confirms that digital development has positively impacted the economic growth of EU member states. This result was confirmed by both Pearson and Spearman correlation. However, the results are ambivalent. The empirical results indicate that the more digitally developed member countries had a higher GDP per capita. However, the positive effect is different. The results confirm that the development of digitalization and GDP increased more dynamically in the more digitally developed EU member states than in the less developed member states. Therefore, an increase in the backwardness of the less developed member countries and not a catch-up can be observed in the period under review.
Abstract
This study highlights the effectiveness of the response surface method in predicting the properties of hardened concrete containing spent foundry sand and manufactured-sand. In current research, different mix proportions are prepared with spent foundry sand and manufactured-sand as partial replacements for fine aggregate. The workability, strength, and durability studies are conducted on all concrete mixes. The test results confirm that the inclusion of 20% of spent foundry sand is optimum for enhancing the strength and durability. Also, the inclusion of 20% of spent foundry sand in manufactured-sand concrete also possesses optimum results in strength and durability. Further, the response surface method has been employed to develop a model for compressive strength prediction. The R-squared and residual sum of squares of error for the compressive strength model were 0.9863 and 2.345, which confirms the goodness of the fit.
Abstract
Local scour poses a grave threat to bridge foundations, potentially causing catastrophic collapses. This study uses FLOW-3D with the Reynolds-Averaged Navier-Stokes model to analyze pier scour and dune formation under bridges. It focuses on submerged debris shapes near the water's surface. Results closely match experiments when specific conditions are met. The study introduces an innovative approach to debris impact assessment. Instead of traditional methods, it proposes a novel equation accounting for debris's effective area and elevation. This enhances reliability by over 20%, improving scour depth assessment in debris-laden scenarios. This advances the understanding of debris's role in local scour, benefiting bridge design and management practices.
Abstract
Present paper shows the different types of tensor product model based linear matrix inequality controller design and feasibility analysis of two degrees of freedom aeroelastic wing section model. The tensor product models are based on reducing or removing the nonlinear behavior of the system and weighting functions. The linear matrix inequality based method results globally asymptotically stable system. The goal of the paper is to examine that selecting and varying the transformation space influences the feasibility of the linear matrix inequality based controller. The paper gives a comparison between the different tensor product models in terms of controller performance. The linear matrix inequality gives feasible solution for the controller design if the transformation space is selected adequately.
Abstract
Integrating thermal energy storage with thermal conversion systems is necessary to maximize their use. Phase change materials are the best media for storing and releasing thermal energy from various basic material types. Because the phase change materials have a high latent heat of fusion, it is often viable to use these characteristics and include the phase change materials in building envelopes to store thermal energy. The paper provides a thorough categorization of the phase change materials and thermal energy storage systems, in addition to an evaluation of their modeling using computational fluid dynamics. The purpose was to highlight computational fluid dynamics as a useful technique for advancing the engineering of thermal energy storage devices.
Abstract
This study evaluated the thermal performance of side divergence and uniform micro-channel heat sinks by comparing and contrasting them. Heat transfer and fluid flow characteristics in these micro-channel configurations were studied using computational fluid dynamics simulations employing ANSYS Fluent 2017 code for this purpose. Laminar flow through micro-channels with a Reynolds number of 207 was the subject of the investigation. The goal is to determine how side divergence affects heat dissipation efficiency concerning traditional uniform micro-channels. The results showed that the best divergence ratio is 1.5 that achieved the highest performance. The study also revealed that side divergence micro-channel heat sinks can achieve thermal performance up to 14% higher than uniform micro-channel heat sinks.
Abstract
This article is dedicated to diagnosis of damage to air distribution in a room with twisted, compact, and flat air jets, and to searching of ways to solving the problem. It was found that in order to avoid damage to the air distribution system in rooms of different purposes and dimensions; it should be air streams of the appropriate types and with the appropriate characteristics. Parameters of a swirled, compact, flat, rectangular air jet when creating comfortable climatic conditions in the rooms of different purposes and dimensions are determined. The relationship between the angle of inclination of the rotating plates (for twisted jets), ratio of sides of the slit (for all rectangular including compact and flat streams) and a long-range of these flows is established.
Abstract
Progress in building construction requires more durable concrete with higher strength. Polymer and water reducer liquids can improve concrete strength and durability. This research aims to improve the mechanical properties of polymer-modified concrete by using anti-slip sand and silica fume to achieve more durable concrete against sulfate attack and higher mechanical properties. The study shows an increase in compressive strength from 25.7 MPa for reference mix to 45.5 MPa using 15% silica fume and 30% Anti-slip sand; tensile strength increased from 2.72 to 4.4 MPa. Flexural strength also increased, and durability to sulfate attack also increased. The study includes the increment of durability against freezing-thawing cycles for different mixes.
