Height-width Ratio Research Articles

Analysis of the Seismic Performance of a Masonry Structure with RC Frames on the First Story with Concrete-Filled Steel Tubular Dampers

The concrete shear walls of masonry structures with RC frames on the first story are low-rise shear walls with a height–width ratio of less than 1. The strength, stiffness, and ductility of these low-rise shear walls are not matched, resulting in poor seismic performance. Based on the idea of the passive control theory and multi-seismic defensive lines, the scheme of a masonry structure with RC frames on the first story with a concrete-filled steel tubular (CFST) dampers is proposed in this paper. To explore the seismic mitigation effect of CFST dampers applied to a masonry structure with RC frames on the first story, the seismic performance under low-reversed cyclic loading of the frame with the CFST dampers is first compared with that of the energy-dissipated low-rise concrete shear wall proposed by previous researchers and the ordinary low-rise concrete shear wall. Furthermore, the response of the masonry structure model with RC frames on the first story with CFST dampers and two other comparative structural models under earthquake action are discussed. The results show that a masonry structure with RC frames on the first story with CFST dampers has a fuller hysteretic loop, lighter pinching, better energy dissipation ability, and better seismic performance. Compared with the other two structures, the energy dissipation capacity of the masonry structure with RC frames on the first story with CFST dampers is significantly improved, by 1.25~1.5 times. The amplification effect of the deformation angle allows the CFST dampers to play a significant role in energy dissipation, whereas the main structure still undergoes a small deformation. The CFST dampers can dissipate more seismic energy to protect the main structure from damage and improve the seismic performance of masonry structures with RC frames on the first story.

Investigation of the Wind-Direction Effect on Buoyancy-Driven Fire Smoke Dispersion in an Urban Street Canyon.

When a fire occurs in a street canyon, smoke recirculation is the most harmful factor to human beings inside the canyon, while the wind condition is an essential factor determining if the smoke is recirculated. This paper focuses on the wind direction's effect on buoyancy-driven fire smoke dispersion in a street canyon, which is innovative research since the effect of wind direction has not been reported before. In this study, an ideal street canyon model with a height-width ratio of 1 was established, and both the wind velocity and wind direction were changed to search for the critical point at which smoke recirculation occurs. The results show that with an increase in the wind direction angle (the angle of wind towards the direction of the street width), the smoke recirculation could be distinguished into three regimes, i.e., the "fully re-circulation stage", the "semi re-circulation stage", and the "non-recirculation stage". The critical recirculation velocity was increased with the increase in the wind direction angle, and new models regarding the critical wind velocity and the Froude number were proposed for different wind direction conditions.

Науково-проектні рішення для створення сучасних малих птахоферм: огляд

The purpose of research is to carry out a review of scientific and project solutions for the creation of modern small poultry farms. Research methods. The review of scientific and project solutions for the creation of modern small poultry farms was carried out based on the materials of available information sources in the following directions: science; projects; comparison. Research results. When creating a scientific design solution for a small poultry farm building for keeping up to 700 laying hens, it is important to take into account the following data: hangar-type premises (width 6 m, height 3,8 m, wall height 3,0 m); the width of places for laying eggs is 0,8 m; the width of the slotted floor is 2,4 m; the width of the solid floor with bedding is 2,8 m. The main thing is to keep laying hens on the floor, cascading in tiers with places for laying eggs. In order to prevent poultry diseases, it was proposed for the first time to increase the technological area for keeping chickens from 6 heads/m2 to 5 heads/m2. Small-sized hangar-type buildings are recommended for keeping poultry on small poultry farms, with dimensions in the width-height ratio: 5,0 m-3,2 m; 8,0 m-4,0 m; 10,0 m-4,8 m; 12,0 m-5,6 m. It is important that during the creation of scientific and project solutions, the technological features of growing different types of poultry (chickens, turkeys, geese, ducks), including those that are seasonal, the duration of growing and livestock fattening, maintenance of parent flock, period of economic use of poultry, etc. Conclusions. According to the results of the review of scientific and project solutions for the creation of modern small poultry farms, which were carried out based on the materials of available information sources in the following directions: science; projects; comparison, it was established: for keeping poultry of various species (chickens, turkeys, geese, ducks) on small poultry farms, small hangar-type buildings are recommended; the basic method of keeping poultry is free floor, cascade keeping, in particular, in rows of chickens and floor - of turkeys, waterfowl (geese, ducks) and keeping poultry in general using aviaries, which brings the conditions of their keeping closer to natural ones. Keywords: geese, turkeys, ducks, chickens, poultry farming, poultry farms, systematization of factors, technological areas, keeping conditions, product quality.

Study on Seismic Performance of Cold-Formed Thin-Walled Steel-Straw Board Composite Wall with Diagonal Brace

The composite wall studied in this paper is based on the original cold-fonned thin-walled steel-straw board composite wall, which is set up with inclined braces and rigid inclined braces to improve its seismic performance. The factors of aspect ratio are analyzed, and the formula of shear bearing capacity of composite wall is deduced. The results show that: (1) When the height-width ratio of the composite wall is 2.4m×1.2m, 1.8m×1.2m and 1.2m×1.2m respectively, the yield strength of the composite wall is 35.78kN, 37.47kN and 54.23kN respectively. The yield strength of the former increases by 4.72 %, and the yield str ength of the latter increases by 44.73 %. (2) Using the effective strip method, the error of the derived shear capacity formula is not large, and the difference between the experimental value and the simulated value is not large, in order to provide some reference for the seismic design of this kind of cold-fonned thin-walled steel-strawboard composite wall with diagonal brace.

How streetscape affects car use: Examining unexamined features of urban environment with fine-grained data

The urban built environment has been extensively studied as a means to reduce car use, but most of the built environment features that have been examined mostly include so-called ‘D-variables’, namely, density, (functional) diversity, (road network) design, etc. The influence of the three-dimensional street space, which cannot be directly understood from maps, is much less studied. However, characteristics of the street space are considered to influence people's travel behavior according to urban design and walkability theories. A major reason for this gap is the lack of data providing relevant information. This paper aims to fill the gap by harnessing new urban data to measure these characteristics of the urban environment and analyze their impact on travel behavior, as indicated by the amount of car use. Among the many characteristics of street space, we chose the quality of street buildings, continuity of street walls, and height-width ratio of the street valley as three key characteristics to study. Using Beijing as a case study, we found that the three street space characteristics had a statistically significant relationship with residents' car use, mainly by influencing travel mode choice. The continuity of street walls is the most influential factor in reducing car use. • We expanded existing research by examining the influence of the street space on urban car use. • The streetscape is measured using street view images, deep learning models and building footprint data. • The continuity of street walls is the most influential streetscape feature in reducing car use.

Eye Gaze and Dominance, Cues for Online Communication with Strangers

Many digital communication platforms of the new economy are built up on mechanisms to initially communicate and/or develop an acquaintance with “strangers” over displayed profile pictures. This study aims to reveal the impact of the direction of eye gaze and perceived dominance from those pictures during the process of pairing online with a stranger, for spending time in a closed environment. Preference between pairs of 66 participants through their profile pictures having a direct or averted gaze and some manipulated by facial width height ratio (fWHR) aiming to increase perceived dominance, were measured by the eye- tracking device. The findings show that when observing the profile pictures of strangers (i) gaze attracts attention to the face of gazing person, (ii) in case of perceived dominance, the gaze of a stranger induces gaze avoidance for participants. The study further predicted when the user is to prefer between pairs of people that one is perceived to be dominant, the probability of choosing the perceived non-dominant is higher. The participants’ preference of the former holdout sample was predicted consecutively by hit ratios of 81.5, 91.4 and 94.9 for three different cases. Analysis of the data revealed no systematic differences between males and females.

Experimental and numerical study on the shear lag behavior of l-shaped double-steel-plate composite shear wall

The shear lag behavior significantly affects the stress distribution of structural members, and ignorance of the shear lag behavior may cause serious engineering accidents. This work shows the shear lag behavior of two l-shaped double-steel-plate concrete composite shear wall (LDSCW) specimens (one with a wide flange and one with a narrow flange) under cyclic loading experimentally investigated. All specimens failed by the local buckling of the steel plate and concrete crushing. The LDSCW shows a good ability to dissipate energy, and the LDSCW with larger flange width exhibits better carrying capacity. The shear lag behavior is serious on the flange of the LDSCW. A finite-element (FE) model is developed to investigate the shear lag behavior of the LDSCW. It is concluded that the influences of the axial compression ratio and the height-width ratio of the flange of the LDSCW on the shear lag effect are significant. Models for predicting the effective flange width (EFW) of LDSCW in the Plastic Stage and Elastic Stage, which make good agreement with experimental results, are developed. The results of this work can provide a reference for the design of the LDSCW.

Axial compression behavior of strength-gradient composite stub columns encased CFST with small diameter: Experimental and numerical investigation

In order to investigate axial compression behavior for strength-gradient composite stub columns encased concrete filled steel tube with small diameter (SGCC), the axial compression experiments of 13 SGCCs and 1 reinforced concrete (RC) stub column were carried out. The influence regularities of height-width ratio, confinement index (θ), stirrup ratio per unit volume (ρv) and axial compressive strength of core concrete on the failure modes, load–displacement curves and load–strain curves of SGCCs were explored. The results showed that SGCCs mainly exhibited three failure modes under axial compression, including shear failure, central crushing and punching failure. By increasing θ and ρv approximately, SGCCs could exhibit ductile failure instead of brittle failure. The deformations of steel tube, longitudinal steel bars, and concrete for SGCCs maintained coordinated during the loading process. Compared with ordinary RC column, the ultimate bearing capacity (Nu) of SGCCs under axial compression was almost doubled. Based on the experimental results, 30 finite element (FE) models were designed to obtain the influence regularities of various parameters on Nu of SGCCs. Applicability of existed design code to predict Nu of SGCCs was also evaluated. Finally, a novel calculation formula for Nu of SGCCs considering constraint effect of stirrups and steel tubes could be proposed, which were in good agreement with the experimental results.

ASSESSMENT OF THERMAL COMFORT IN URBAN PUBLIC SPACE IN A TROPICAL CITY: A STUDY OF RAJSHAHI, BANGLADESH

Sustainable design approaches reduce energy consumption of urban form and the environment. Urban public space design is an efficient sustainable strategy to improve thermal and microclimatic conditions of outdoor spaces. A tropical city like Rajshahi, Bangladesh, an example of a rapid urbanization, is now dealing with the challenge of sustainable urban development, especially in the urban public space where thermal comfort makes a vital role for active to use of outdoor space in the various time. People’s activities and usages of outdoor space particularly urban public place which is the most viable and sustainable features of urban design is directly affected by thermal setting and thus affect people’s activities. This research aims to calculate the thermal comfort indices to find out the comfort condition of the urban public space by using a CFD based simulation software “ENVI-Met”. Online sources are used to collect site specific microclimatic data for thermal comfort. Data is then synthesized to find out MRT and thermal comfort condition. The aim is to develop and recommend a checklist of comfortable urban form and potential design and materials features to investigate the scope of improvement of outdoor thermal comfort of urban public space of study area. Both the physical (height width ratio of urban form, vegetation, water features, orientation, materials) has strong impact on improving thermal comfort and activities. This research suggests some urban design options for an effective and comfortable outdoor space in the context of tropical city like Rajshahi in the end.

Seismic performance of a shear-type energy dissipation brace: Experimental investigation and numerical analysis

In this study, a novel shear-type energy dissipation brace (SEDB) was proposed, which integrated multiple pieces of steel shear plates on a single brace. The brace stiffness and yield load can be adjusted by changing the number of pieces and layers of the steel shear plates, which is more flexible than the traditional shear-type dampers. Three configurations of SEDBs were developed, including the flat steel plate-SEDB (F-SEDB), F-SEDB without core tube and corrugated steel plate-SEDB (C-SEDB). The quasi-static cyclic tests were conducted on three SEDBs to investigate the seismic performance. Experimental results showed that the proposed SEDB can achieve a stable hysteretic behavior, especially by adopting the core tube to prevent global out-of-plane deformation. Meanwhile, the C-SEDB has a more stable energy dissipation performance due to the high out-of-plane stiffness of the corrugated steel plates. The design procedure of the SEDBs was developed. Meanwhile, a finite element model was established and verified by the experimental results. The influences of the height-thickness and height-width ratio of steel plates were systematically investigated, which benefited the application and offered suggestions in engineering design.

Evolution of competitive traits changes species diversity in a natural field.

Studying the interaction between evolutionary and ecological processes (i.e. eco-evolutionary dynamics) has great potential to improve our understanding of biological processes such as species interactions, community assembly and ecosystem functions. However, most experimental studies have been conducted under controlled laboratory or mesocosm conditions, and the importance of these interactions in natural field communities has not been evaluated. In this study, we focused on the contemporary divergence of a competitive trait (the height-width ratio) of an annual grass Eleusine indica between urban and farmland populations and investigated how trait evolution affects ecological processes by transplanting E. indica individuals from lineages with different trait values into semi-natural grassland. The competitive trait of the transplanted individuals not only affected their own growth and fitness, but also affected the vegetative growth of the competing species and the species diversity. These results indicate that the evolution of competitive traits, even in a single species, can influence the community species diversity through changes in interspecific interactions. Eco-evolutionary interactions therefore play a crucial role in natural field environments. Our results suggest that understanding intraspecific variation in competitive traits driven by rapid evolution is essential for understanding interspecific competitive interactions, community assembly and species diversity.

Mathematical modeling and multi-objective optimization on the rectangular micro-channel heat sink

A microchannel heat sink (MCHS) is a compact and efficient liquid-cooling device that satisfies the heat dissipation requirements of high-power electronic equipment. This study develops a mathematical model of a rectangular MCHS based on the differential equation of energy conservation and derives the thermal resistance using structural parameters. Single phase flow and fully developed conditions are considered. The correlations of the convective heat transfer coefficient and the flow resistance are examined and comparatively studied for wide-ranging geometric parameters. Both experimental and numerical methods are employed to validate the model. The effect of the height–width ratio on the thermo-hydrodynamic performance indicates a ratio greater than ten is uneconomical. Finally, a multiobjective optimization model is established to simultaneously minimize the thermal resistance and the pumping power. The Pareto front is obtained using the non-dominated sorting genetic algorithm, and the optimal case reduces the thermal resistance by 25% compared to the experimental case under the same pumping power consumption. The mathematical model and the multiobjective optimization method are beneficial for the design of an MCHS owing to the high convenience and reliability.

Experimental Investigation and Parametric Analysis of the Mechanical Properties of Aluminum Alloy Thin-Walled Hollow Columns under Axial Compression

Five specimens were cut from an aluminum alloy thin-walled hollow column to complete a tensile test, and the strength of the aluminum alloy was measured to be 200.18 MPa. The Ramberg–Osgood model was compared with the stress-strain relationship of the test results, and the fitting regression coefficient was more than 0.99. Four groups of axial compression trials of aluminum alloy thin-walled hollow columns with different heights were accomplished, and the test phenomena and data were concurrently observed and recorded. The results show that the axial compressive bearing capacity of aluminum alloy thin-walled hollow columns does not change with the change in column height, the mean value is 73.72 kN, and the corresponding covariance is only 2.14%. Local buckling failures appeared in all of these columns, and the failure locations were distributed at each height of the test pieces. The stiffness of the column decreased with the increase in height and width ratio, and the varying trend between them obeys exponential distribution. The displacement that corresponds to the ultimate load increased with the increase in the height-width ratio, and the increasing trend follows a linear relationship with the change in column height.

Acoustic wave propagation mechanism in the local stiffened structure of space station cabin using finite element method

Acoustic-based leakage detection and location in a spacecraft has attracted many researchers’ interest. Due to the fact that wave propagation through the stiffened structure is too complicated to be comprehensively understood, current leakage detection technologies have low-quality performance. Using numerical simulations, this paper parametrically investigates wave propagation across stiffened structure under different configurations. First, wave propagation through the stiffened structures with different stiffener heights is analyzed, showing that acoustic propagation features are different from Reusser’s model. Second, the stiffened structures with different widths are analyzed; meanwhile, the two cases of too large and too small stiffened ratios were compared. Acoustic wave propagation paths become complicated due to acoustic mode conversions. Third, different configurations of structure types are addressed. When the stiffener’s height–width ratio was large, the acoustic wave first reached the bottom of the stiffened block and then traveled up to the top of the stiffened block. When the stiffener’s height–width ratio was small, the acoustic wave reached the incident side at the bottom of the stiffened block and then propagated separately.

A Multifeature-Assisted Road and Vehicle Detection Method Based on Monocular Depth Estimation and Refined U-V Disparity Mapping

Usually, the detection process of traffic objects, such as vehicles, finds the visual input lacks the necessary depth information, so it is difficult to directly and quickly obtain the results. Typically, to separate the objects from the complex background, it is necessary to utilize a complex model or prior knowledge, which can be computationally expensive or simply infeasible. To battle this issue, depth visual information is used in this paper to accurately segment roads and vehicles, so it doesn’t need to use complex models to detect objects in the visual input. First, an unsupervised deep learning-based monocular depth estimation method is used to obtain the stereo disparity map. Then a non-parametric, refined U-V disparity mapping method is used to obtain the road region of interest. Next, this paper uses the road parallel scanning to determine the source and vanishing points and uses the adjacent disparity similarity algorithm to complement and extract the target region to detect roads and vehicles. This algorithm uses multi-feature fusion such as height-width ratio, perspective ratio, and area ratio to accurately segment the target region, and the effectiveness of the proposed method is tested on a public dataset. The experimental results show that the proposed model can accurately and efficiently detect roads and vehicles in a variety of scenarios.

Effects of width-height ratio and roof-floor strength on the mechanical characteristics of cemented gangue backfill pier-column.

Cemented gangue backfill pier-column (CGBP) which was made of coal gangue, fly ash, cement, and water is the supporting component of the goaf in partial backfill mining or constructional backfill mining for controlling the surface subsidence of coal mining. The width-height ratio and roof-floor strength directly affect the bearing capacity of CGBP under axial compression, which is essential for the design of CGBP. Herein, the effect of width-height ratio (1:3-1:1) on the mechanical characteristics of CGBP with different curing ages under uniaxial compression was system studied through experiment, and the damage process was analyzed by ultrasonic equipment and DIC. Based on the experimental results and discrete element theory, a three-phase numerical model for CGBP was established, which considered the real aggregate shape and distribution and the mechanical characteristics of each phase. Then, the effects of the end friction coefficient and the strength ratio of roof-CGBP-floor combination on the strength and failure characteristics of CGBP (large width-height ratio: 1:1-4:1) were investigated. The results show that CGBP shows the width-height ratio effect obviously and the strength and ductility increase with the increase of the width-height ratio, and the width-height ratio effect increases with the increase of curing age and strength ratio. The end friction constraint is the main reason for the width-height ratio effect, and the higher the friction coefficient is, the larger the width-height ratio effect shows, and the width-height ratio effect disappears without end friction constraint. The increase of the width-height ratio of CGBP and the strength ratio of the roof-CGBP-floor combination increases the strength of the combination. Whether the strength of the combination is greater than that of CGBP may have a roof-floor strength threshold or a strength ratio threshold, which are between 31.44-54.11MPa and 3.75-6.44, respectively. When the strength of the roof and floor is different, the strength of the combination is mainly controlled by the weak carrier and increases with the increase of the strength of the weak carrier. The peak strain energy of CGBP and combination increases with the increase of end friction coefficient, width-height ratio, and strength of roof and floor. The experimental and simulation results can be used to guide the design of CGBP in constructional backfill mining or partial backfill mining.

Non-contact detection method of pregnant sows backfat thickness based on two-dimensional images.

Since sow backfat thickness (BFT) is highly correlated with its service life and reproductive effectiveness, dynamic monitoring of BFT is a critical component of large-scale sow farm productivity. Existing contact measures of sow BFT have their problems including, high measurement intensity and sows' stress reaction, low biological safety, and difficulty in meeting the requirements for multiple measurements. This article presents a two-dimensional (2D) image-based approach for determining the BFT of pregnant sows when combined with the backfat growth rate (BGR). The 2D image features of sows extracted by convolutional neural networks (CNN) and the artificially defined phenotypic features of sows such as hip width, hip height, body length, hip height-width ratio, length-width ratio, and waist-hip ratio, were used respectively, combined with BGR, to construct a prediction model for sow BFT using support vector regression (SVR). Following testing and comparison, it was shown that using CNN to extract features from images could effectively replace artificially defined features, BGR contributed to the model's accuracy improvement. The CNN-BGR-SVR model performed the best, with R2 of 0.72 and mean absolute error of 1.21 mm, and root mean square error of 1.50 mm, and mean absolute percentage error of 7.57%. The results demonstrated that the CNN-BGR-SVR model based on 2D images was capable of detecting sow BFT, establishing a new reference for non-contact sow BFT detection technology.

Analysis of Buckling Deformation for the Side Plate of Rectangular CSFT Column Based on Plate Theory with Bi-Axial Loads

In this paper, under the condition of bidirectional stress, the buckling deformation of the side plate in a rectangular concrete-filled steel tube (CFST) column has been studied in detail. We have conducted a theocratical analysis, an experimental validation and a finite element simulation to investigate the influences of the height-width ratios and Nominal Poisson’s ratios on the buckling form of the side plate, and we also try to explain the change of buckling form between unidirectional and bidirectional stress, both of them can provide a good reference and basis for design and application of the CFST column. The specific work can be summarized as follows: Firstly, a theoretical analysis has been conducted to study the buckling coefficient solution method of the thin plate under the conditions of axial compress and transverse tension. Then, under the conditions of the unidirectional and the bidirectional stress, a comparative study is carried out to investigate the changing relationship of the buckling coefficient (k) of the side plate; the results indicate that the buckling characteristic is changed due to the bidirectional stress, meanwhile, the buckling coefficient and the number of buckling half-wave will increase. Furthermore, the existing outcomes and the numerical simulations are adopted to study the relevance between the number of the elastic buckling half-wave in the side plate and the corresponding height-width ratio of the component; the results indicate that the former is larger than the latter. Finally, based on the obtained, the buckling relationship curve, the conclusion can be drawn as follows: when the bidirectional stress has been applied to the side plate, there is an equal interval between the different buckling half-waves; meanwhile, the interval shows a quadratic function reduce trend with the increase of nominal Poisson’s ratio.

Geomorphologic Evolution and Morphometric Analysis of the Upper Basin (Güzelsu) of the Engil River (Van)

The study area is located in the Eastern Anatolian Plateau found in the Alpine-Himalayan fold mountain belt. The Engil River Upper Basin (Güzelsu) is within the Lake Van Closed Basin, the largest soda lake in this belt in terms of volume and area. This study aims to investigate the geomorphologic evolution of the Güzelsu Basin and support this development with morphometric analysis. With this aim, a Digital Elevation Model (DEM) was created with the aim of quantifying and evaluating field observations and findings, 22 subdrainage areas located in the basin was determined by the DEM. The indices of Hypsometric integral, Hypsometric curve, Basin shape, Elongation ratio, Drainage basin asymmetry, Mountain front sinuosity ratio, Valley width-height ratio were applied to these drainage areas which were formed depending on internal and external processes. When the geomorphological and sedimentological findings in the field studies were evaluated with the applied index results, it was revealed that the basin geomorphology was formed under the influence of tectonism, climate and fluvial processes.

Research on Visual Preference of Chinese Courthouse Architecture Appearance

Whether courthouse architecture should be solemn or friendly is a topic worth exploring. Currently, a large quantity of courthouse buildings have been constructed in China, but the architectural style differs greatly. This situation provides a good foundation for the study on visual preference appraisal of the external form of courthouse buildings. This research selected 50 representative courthouse buildings as the research object and set architectural style, height–width ratio, window–wall ratio, and open ground in front of the buildings as the physical properties under study. Participants of different demographic characteristics were chosen to conduct a photo stimulation experiment. The results obtained were analyzed by SPSS. According to the research results, the neoclassical courthouse building with a large window–wall ratio, small height–width ratio, and large open ground is the most favorite among the participants; participants of different demographic characteristics render different visual preference appraisals of the external form of Chinese courthouse buildings. Contemporary Chinese court building should have a new image. This research can be taken as a reference for the external design of Chinese courthouse buildings.