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From the factors that affect shear strength of reinforced concrete (RC) beams, the study examines the effect of controversial parameters, width-to-depth (b/d) and effective length-to-depth (l_eff/d) ratio on shear strength of RC slender beams.

The researchers utilized a database of 676 experimental test results from ACI-DAfStb database, Conducted regression analysis to examine relationship between b/d and l_eff/d ratios and shear strength, compare and analyze sensitivity to changes in b/d and l_eff/d ratios for the selected 12 shear models for RC beams.

Increasing b/d ratio enhanced shear strength until b/d ˜ 3, but further increases had limited impact and increasing l_eff/d ratio resulted in decreased shear strength. From comparative analysis, the models provided by various design standards were found to be safe, with EC-2 and JSCE models being conservative. From considered research models, Campione and Arslan models were conservative, while Kim and White model were observed to be unsafe. Sensitivity analysis indicated ACI318-19, JSCE, CEB-FIP-90 and Arslan models were sensitive to changes in b/d and l_eff/d ratios. National code models generally captured shear strength characteristics well. Certain models suggested a constant/decreasing b/d effect despite observed shear strength enhancement. Most models indicated improved shear strength with an increasing l_eff/d ratio, contrary to experimental findings while TS500 and Hwang models aligned with experimental results.

The study's limitations include the dependence on the available database, which may not encompass all possible experimental scenarios. Further research should aim to expand the database and investigate additional parameters that may influence shear strength in RC beams.

The findings of this study have practical implications for the design and analysis of RC beams by suggesting that the width-to-depth and length-to-depth ratios should be carefully considered to optimize shear strength. The identified models can assist engineers in selecting appropriate shear strength prediction models based on specific design scenarios.

The study contributes to the advancement of knowledge in the field of reinforced concrete beam design, which has implications for the safety and reliability of structural systems. By understanding the factors influencing shear strength, engineers can design more efficient and robust structures, ensuring the safety of buildings and infrastructure.

This study provides valuable insights into the influence of the width-to-depth and effective length-to-depth ratios on shear strength in reinforced concrete beams. It contributes to the understanding of these factors and their impact on shear strength, addressing the lack of consensus among researchers. The comparative analysis of shear models and the sensitivity analyses add value by identifying the models that align better with experimental observations. The study emphasizes the need for accurate models that account for these factors and highlights the importance of further research to refine and develop improved predictive models.

Aircraft noise is dominant for residents near airports when planes fly at low altitudes such as during departure and landing. Flaps, wings, landing gear contribute significantly to the total sound emission. This paper aims to present a passive flow control (in the sense that there is no power input) to reduce the noise radiation induced by the flow over the cavity of the landing gear during take-off and landing.

The understanding of the noise source mechanism is normally caused by the unsteady interactions between the cavity surface and the turbulent flows as well as some studies that have shown tonal noise because of cavity resonances; this tonal noise is dependent on cavity geometry and incoming flow that lead us to use of a sinusoidal surface modification application upstream of a cavity as a passive acoustics control device in approach conditions.

It is demonstrated that the proposed surface waviness showed a potential reduction in cavity resonance and in the overall sound pressure level at the majority of the points investigated in the low Mach number. Furthermore, optimum sinusoidal amplitude and frequency were determined by the means of a two-dimensional computational fluid dynamics analysis for a cavity with a length to depth ratio of four.

The noise control by surface waviness has not implemented in real flight test yet, as all the tests are conducted in the credible numerical simulation.

The application of passive control method on the cavity requires a global aerodynamic study of the air frame is a matter of ongoing debate between aerodynamicists and acousticians. The latter is aimed at the reduction of the noise, whereas the former fears a corruption of flow conditions. To balance aerodynamic performance and acoustics, the use of the surface waviness in cavity leading edge is the most optimal solution.

The proposed leading-edge modification it has important theoretical basis and reference value for engineering application it can meet the demands of engineering practice. Particularly, to contribute to the reduce the aircraft noise adopted by the “European Visions 2020”.

The investigate cavity noise with and without surface waviness generation and propagation by using a hybrid approach, the computation of flow based on the large-eddy simulation method, is decoupled from the computation of sound, which can be performed during a post-processing based on Curle’s acoustic analogy as implemented in OpenFOAM.

Hydrothermal waves represent the preferred mode of instability of the so-called Marangoni flow for a wide range of liquids and conditions. The related features in classical rectangular containers have attracted much attention over recent years owing to the relevance of these oscillatory modes to several techniques used for the production of single crystals of semiconductor or oxide materials. Control or a proper knowledge of convective instabilities in these systems is an essential topic from a material/product properties saving standpoint. The purpose of this study is to improve our understanding of these phenomena in less ordinary circumstances.

This short paper reports on a numerical model developed to inquire specifically about the role played by sudden changes in the available cross-section of the shallow cavity hosting the liquid. Although accounting for the spanwise dimension would be necessary to derive quantitative results, the approach is based on the assumption of two-dimensional flow, which, for high-Pr fluids, is believed to retain the essence of the involved physical processes.

Results are presented for the case of a fluid with Pr = 15 filling an open container with a single backward-facing or forward-facing step on the bottom wall or with an obstruction located in the centre. It is shown that the presence of steps in the considered geometry can lead to a variety of situations with significant changes in the local spectral content of the flow and even flow stabilization in certain circumstances. The role of thermal boundary conditions is assessed by considering separately adiabatic and conducting conditions for the bottom wall.

Although a plethora of studies have been appearing over recent years motivated, completely or in part, by a quest to identify new means to mitigate these instabilities and produce accordingly single crystals of higher quality for the industry, unfortunately, most of these research works were focusing on very simple geometries. In the present paper, the causality and interdependence among all the kinematic and thermal effects mentioned above is discussed.

Limitations in traditional manufacturing methods currently employed in the production of acoustic devices, restricts the development of design led performance improvements. These devices are used to control sound energy and are commonly employed for tailoring room acoustics. solid freeform fabrication allows the production of acoustic structures more complex than traditionally manufactured devices. This paper aims to focus on a novel absorber based on destructive interference, considering performance, design and manufacture.

Selective laser sintering has been used in the investigation of the performance and manufacturing possibilities and limitations of a novel destructive interference absorber. Validation of the absorber performance is benchmarked against a conventional resonant absorber and compared to published results. The implications for acoustic devise design, the advances and limitations in manufacture using solid freeform fabrication techniques and potential applications are discussed.

An original absorber design has been shown to exhibit comparable acoustic absorption to that of a traditional solution. The nature of the geometry of the novel absorber demonstrates that the design flexibility afforded by solid freeform fabrication processes holds potential for applications incorporating new types of acoustic absorber. The use of solid freeform fabrication has demonstrated its potential to the application of acoustics, and has highlighted limitations due to post‐processing, material strength and the precision of the selectivity process.

Solid freeform fabrication techniques enable a new family of specifically engineered acoustic absorbers capable of incorporating performance benefits over conventional absorbers.

This paper focuses on room acoustic applications, the creation of high performance, conformal absorbers, applicable to a wide range of applications within the aerospace, automotive and construction industries, where space, weight and performance are key criteria.

This study explores the difference in occupants' satisfaction with biophilic features in high-rises, townhouses, and villas in Dubai to identify new strategies that promote more human-nature connections. The study also serves as a benchmark for applying Biophilic Design in the Gulf region and bridging between biophilic theory and practice.

A mixed-mode approach was used, combining surveys from occupants and interviews with experts (3 policymakers, a developer, and a biophilic design educator). The survey collected occupants' satisfaction and acceptance of proposed strategies, and the interviews validated the potentially accepted solutions.

The results indicated high overall satisfaction with biophilic features despite neutral/low satisfaction with specific features. In high-rise buildings, respondents showed high acceptance for different proposed strategies; 76.4% for adaptive control of balconies by season, 82.7% for utilizing outdoor roof gardens, 78.9% for indoor gardens, and 71.8% for vertical farming. Additionally, respondents accepted social strategies; 63.6% agreed to join clubs promoting environmental events, and 75.4% accepted participating in outdoor recreational activities accompanied by local environmental education. The interviews showed an inclination toward incentive programs instead of obligations.

Unlike former studies that assessed indoor environmental qualities without referring to biophilic theory or limited reference to biophilic design, this study provides a novel approach for bridging theory and practice by integrating biophilic design into residential buildings for Dubai's future developments. Additionally, the authors suggest validated proposals to enhance the occupants' biophilic living experience, serving as a benchmark for biophilic application in the Gulf region.