Influence of different mining layouts on the mechanical properties of coal

Non-pillar mining,top-coal caving and protected coal seam mining are the most popular mining methods in coal exploitation,and the different mining layouts will change the stress state and failure mechanism of coal in front of the working face.In this paper,mining-induced mechanical behaviors under three mining layouts have been simulated in the laboratory to investigate the effects of mining layouts on the deformation and strength of coal.Furthermore,the coal failure mechanism under different mining layouts is analyzed microscopically.The experimental results indicate that the stage characteristics of the coal deformation are obvious.Under the serial action of non-pillar mining,top-coal caving and protected coal seam mining layouts,the values of radial deformation,volume strain and Poisson's ratio increase,while the peak strength and deformation modulus decrease at the same buried depth,and the peak strength under non-pillar mining,top-coal caving and protected coal seam mining is about 3.0,2.5 and 2.0 times of the initial confining pressure,respectively.The results also indicate that the trend of the coal deformation decreases with the increase of the buried depth under the same mining layout,while the strength and deformation modulus increase,and the failure mechanism under three mining layouts is dominated with shear/tensile failure.

Total Ionizing Dose Radiation Effects on MOS Transistors with Different Layouts

Both nMOS and pMOS transistors with two-edged and multi-finger layouts are fabricated in a standard commercial 0.6μm CMOS/bulk process to study their total ionizing dose （TID） radiation effects. The leakage current, threshold voltage shift, and transconductance of the devices are monitored before and after T-ray irradiation. Different device bias conditions are used during irradiation. The experiment results show that TID radiation effects on nMOS devices are very sensitive to their layout structures. The impact of the layout on TID effects on pMOS devices is slight and can be neglected.

Numerical simulation of spatial distributions of mining-induced stress and fracture fields for three coal mining layouts

In this study, the spatial distributions of stress and fracture fields for three typical underground coal mining layouts, Le, non-pillar mining （NM）, top-coal caving mining （TCM） and protective coal-seam mining （PCM）, are modeled using discrete element software UDEC, The numerical results show that different mining layouts can lead to different mining-induced stress fields, resulting in diverse fracture fields, For the PCM, the mining influenced area in front of the mining faces is the largest, and the stress concentration factor in front of the mining faces is the lowest, The spatial shapes of the mining-induced fracture fields under NM, TCM and PCM differ, and they are characterized by trapezoidal, triangular and tower shapes, respectively, The fractal dimensions of mining-induced fractures of the three mining layouts decrease in the order of PCM, TCM and NM, It is also shown that the PCM can result in a better gas control effect in coal mines with high outburst potential, The numerical results are expected to provide a basis for understanding of mining-induced gas seepage fields and provide a reference for high- efficiency coal mining,

Functional Features and Layouts of Yangzhou Residential Gardens in the Late Qing Dynasty and the Early Republic of China: A Case Study of Residential Gardens of Officials, Merchants and Literati

On the basis of analyzing socio-economic structures, social classes and their relations in the late Qing Dynasty and the early Republic of China, this paper took residential gardens of three principal groups(officials, merchants and literati) for example, analyzed functional features and layouts of the gardens, explored artistic characteristics and cultural connotations of the local residential gardens, so as to provide references for the conservation and construction of historic and cultural cities, design and expression of modern urban livable spaces.

Optimization of Building Layouts to Increase Wind Turbine Power Output in the Built Environment Assumed to Be Installed at Fukushima City and Tsu City in Japan

It is very important to consider proper intelligent integration and locations of renewable energy sources into the built environment for developing smart cities. Wind speed distribution study in the built environment is very essential for analyzing the wind turbine performance located in the built environment. In this work, the building layout like nozzle is proposed and the objective is to optimize the building layout for increasing electrical energy output of wind turbine, assumed to be installed in actual cities of Japan. The wind speed distribution across buildings is numerically simulated by using CFD-ACE+. Wind turbine power output is estimated using the power curve of a real commercial wind turbine and wind speed distribution is simulated using CFD software. The meteorological data of Fukushima city and Tsu city of Japan are utilized for evaluating the wind speed distribution profile across the building and for finding the electrical energy output from wind turbine. The proposed building models, which have the angle between two buildings like nozzle of 90°, 135° and 180°, can provide the wind acceleration at the back of buildings for the wind blowing from the main wind direction and the angle of 135°is optimum building layout. In the case of installing the proposed building model in Fukushima city and Tsu city, the wind energy output in winter season is higher while that in summer season is lower irrespective of the buildings’ angle. The interaction between the change in frequency distribution of wind speed and direction throughout the year and the location of open tip of building model decides the power generation characteristics of the proposed building model.

Study on Urban Forest Construction Concepts and Layouts in Taizhou City

Taizhou is an economically-developed port city on the golden coastline of China, characterized by typical coastal and combined green cores, mountains and waters, and special plants. This paper analyzed natural conditions and city features of Taizhou, assessed current construction of local urban forests, and proposed pertinent construction concepts in view of diversifi ed needs of urban development on forest construction. On the basis of the city development, principles of urban forest layout were put forward, and the overall structure of "one core, one belt, two rings, three corridors, four groups, fi ve windows, and multiple bases" was given for the construction of urban forest in coastal landscape cities, in addition, the effect and feasibility of the layout were analyzed.

Air-vent layouts and water-air flow behaviors of a wide spillway aerator

A spillway aerator should guarantee favorable flow conditions in the coupled water-air system even if the aerator is unconventionally wide. Eight air-vent configurations are devised and incorporated into a 35-m wide chute aerator for a generalized study. Computational fluid dynamics(CFD) simulations are performed to explore their effects on water-jet and air-cavity features. The Re-normalisation group(RNG) k-ε turbulence model and the two-fluid model are combined to predict the two-phase flow field. The results demonstrate appreciable influences of the vent layouts on the water-air flow. The air vents stir the air motion and re-distribute the cavity air pressure. Once the vent layout is modified, reciprocal adjustments exist between the jet behavior and air-pressure field in the cavity, thus leading to considerable differences in air-flow rate, jet-trajectory length, vent air-flow distribution across the chute, etc. The large width plays a discernable role in affecting the aerated flow. Telling differences exist between the near-wall region and the central part of the chute. To improve the duct pressure propagation, a gradual augment of the vent area should be assigned towards the chute center. Relative to single-slot vents across the flow, the layouts with segregated vents gain by comparison. A designer should see to it that a vented aerator operates satisfactorily for a given range of flow discharges.

Some possible station layouts and characteristics of evacuated tube transportation

Since Maglev vehicles will run in a closed vacuum tube,the layout of the terminal stations of evacuated tube transportation（ETT） will differ from the traditional railway stations.This paper deals with some possible station layouts of ETT,e.g.,a station with an airlock,a station without an airlock,above ground and underground stations,and stations with either level arrayed or rotation platforms.Then different station layouts are compared,and characteristics of each are analyzed.Finally,a more secure mode for ETT station layouts is suggested,which can be the basis for future ETT station layout and designs.

Optimizing trade-offs between light transmittance and intraspecific competition under varying crop layouts in a maize-soybean strip relay cropping system

Light is one of the most important environmental factors for plant growth and development.In relay cropping systems,crop layouts influence light distribution,affecting light use efficiency(LUE).However,the response of light interception,light conversion,and LUE for relay maize and relay soybean to different crop layouts remains unclear.We aimed to quantify the effect of crop layout on intraspecific and interspecific competition,light interception,light conversion,LUE,and land productivity between relay maize and relay soybean.We conducted a field experiment for four consecutive years from 2017 to 2020 in Sichuan province,China,comparing different crop layouts(bandwidth 2.0 m,row ratio 2:2;bandwidth 2.4 m,row ratio 2:3;bandwidth 2.8 m,row ratio 2:4),with sole maize and sole soybean as controls.The results showed that relay maize in the 2.0 m bandwidth layout had the largest leaf area index and plant biomass,the lowest intraspecific competitive intensity and the highest aggressiveness.Compared to a bandwidth of 2.0 m,a bandwidth of 2.8 m significantly decreased relay maize leaf area index by 11%and plant biomass by 24%,while a 2.4 m bandwidth caused roughly half these reductions.The 2.0 m bandwidth layout also significantly improved crop light interception and LUE compared to sole maize.The light interception,light interception rate,light conversion rate and LUE in relay maize all decreased significantly with increasing bandwidth,but they increased in relay soybean.The increased light transmittance to the lower and middle canopy with increasing bandwidth did not compensate for the loss of relay maize yield caused by increased intraspecific competition.However,it enhanced the yield of relay soybeans.Increasing the bandwidth by 80 cm increased the relay maize intraspecific competition by 580%,and reduced maize yield by 33%,light interception by 12%,and LUE by 18%.In contrast,the relay soybean intraspecific competition was reduced by 64%,and the soybean yield was increased by 26%,light interception by 32%and LUE by 46%.Relay cropping systems with a 2.0 m bandwidth optimize the trade-off between light transmittance and intraspecific competition of relay crops.These systems achieve the highest LUE,group yield and economic benefits,making them a recommended crop layout for the southwest regions of China.Our study offers valuable insights for developing strip relay cropping systems that maximize light utilization and contributes to the theoretical understanding of efficient sunlight use in relay cropping practices.

Optimization of spatial layouts for underground facilities to achieve carbon neutrality in cities:A multi-agent system model

Subways,underground logistics systems and underground parking,as the primary facilities types of underground,contribute significantly to the achievement of carbon–neutral cities by moving surface transportation to underground,thereby releasing surface space for the creation of more urban blue-green space for carbon sink.Therefore,in-depth studies on carbon neutrality strategies as well as reliable layout optimization solutions of these three types of underground facilities are required.This study proposes a spatial layout optimization strategy for carbon neutrality using underground hydrogen storage and geothermal energy for these three types of underground facilities employing a multi-agent system model.First,three spatial layout relationships,competition,coordination,and followership,between five underground facilities that contribute to emission reduction were investigated.Second,the implementation steps for optimizing the spatial layout of underground facilities were determined by defining the behavioral guidelines for spatial environment,underground facility,and synergistic agent.Finally,using the Tianfu New District in Chengdu City,China,as a case study,layouts of underground facilities under three different underground space development scenarios were simulated to verify the model.The findings of this study address the gap in the research on underground spatial facilities and their layout optimization in response to emission reduction.This study provided a significant reference for the study of underground space and underground resources at the planning level to aid in achieving carbon–neutral cities.

Numerical modeling of dam-break flood through intricate city layouts including underground spaces using GPU-based SPH method

This paper applies the meshfree Smoothed Particle Hydrodynamics （SPH） method with Graphical Processing Unit （GPU） parallel computing technique to investigate the highly complex 3-D dam-break flow in urban areas including underground spaces. Taking the advantage of GPUs parallel computing techniques, simulations involving more than 107 particles can be achieved. We use a virtual geometric plane boundary to handle the outermost solid wall in order to save considerable video card memory for the GPU computing. To evaluate the accuracy of the new GPU-based SPH model, qualitative and quantitative comparison to a real flooding experiment is performed and the results of a numerical model based on Shallow Water Equations （SWEs） is given with good accuracy. With the new GPU-based SPH model, the effects of the building layouts and underground spaces on the propagation of dambreak flood through an intricate city layout are examined.

Study of CEPC performance with different collision energies and geometric layouts

The Circular Electron-Positron CoUider （CEPC） is one of the largest projects planned for high energy physics in China. It would serve first as a Higgs factory and then upgrade to a hadron collider. In this paper we give the 50 km and 100 km design for both single ring and double ring schemes, including Z boson, W boson and Higgs boson, by using an optimized method. Also, we give the potential of CEPC running at the Z and W poles. We analyse the relationship of luminosity with circumference and filling factor, which gives a way to evaluate the choice of geometry, and compare the nominal performances of CEPC-SPPC, LHC and FCC.

Mosque layout desisn： An analytical study of mosque layouts in the early Ottoman period

This study attempts to quantify the influence of spatial configuration on the functional efficiency of mosque layouts in the early Ottoman period. The literature review consists of two parts. The first part is a theoretical study of the relationship between spatial configuration and functional efficiency of mosque layouts. This part highlights the key syntactical characteristics and effect of spatial configuration on the level of functional efficiency using space syntax theory. The second part is an analytical comparative description of the changes and transfor- mations in the configurations of mosque layouts. The architectural styles are classified into six types based on layout designs. The main benchmarks and indicators involved in measuring the functional efficiency of mosque layouts are analyzed using the A-graph 2009 software program, which provides numerical results. This analysis compares entire samples of mosque layout designs for each category. The numerical results indicate the effect of spatial configurations and the functions of mosque layouts. This study shows that mosques with courtyard layouts are accessible, efficient, and flexible in terms of function because of their distinct syntactical and morphological spatial structures.

Wind tunnel investigation of different engine layouts of a blended-wing-body transport

A 2%scale,cruising version of a 450-seat class Blended-Wing-Body(BWB)transport was tested in the China Aerodynamic Research and Development Center’s FL-262.4-by-2.4-meter subsonic wind tunnel.The focus of the wind tunnel test was to investigate the aerodynamic performance of the latest BWB transport design,which would also aid in choosing a final engine arrangement in the three most potential engine integration layouts.The wind tunnel model can be tested with and without the nacelle and has three sets of different nacelle/tail integration positions.Computational Fluid Dynamics(CFD)simulations were performed in engine-aircraft integration design to find appropriate nacelle installing parameters of each layout.The comparison of CFD with experimental results shows good agreement.Wind tunnel measurements indicate that the tail-mounted engine layout produces the minimum drag penalty,while the fuselage-mounted engine layout increases drag the most.Experimental pressure measurement illustrates the effect of nacelle integration on the wing-body surface pressure distribution.This experimental and numerical research provides a reference for future BWB Propulsion-Airframe Integration(PAI)design.

Aerodynamic mechanisms in bio-inspired micro air vehicles:a review in the light of novel compound layouts

Modern designs of micro air vehicles(MAVs)are mostly inspired by nature's flyers,such as hummingbirds and flying insects,which results in the birth of bio-inspired MAVs.The history and recent progress of the aerodynamic mechanisms in bio-inspired MAVs are reviewed in this study,especially focused on those compound layouts using bio-inspired unsteady aerodynamic mechanisms.Several successful bio-mimicking MAVs and the unsteady high lift mechanisms in insect flight are briefly revisited.Four types of the compound layouts,i.e.the fixed/flapping-wing MAV,the flapping rotary wing MAV,the multiple-pair flapping-wing MAV,and the cycloidal rotor MAV are introduced in terms of recent findings on their aerodynamic mechanisms.In the end,future interests in the field of MAVs are suggested.The authors'review can provide solid background knowledge for both future studies on the aerodynamic mechanisms in bio-inspired MAVs and the practical design of a bio-inspired MAV.

Ensemble machine learning framework for daylight modelling of various building layouts

The application of machine learning(ML)modelling in daylight prediction has been a promising approach for reliable and effective visual comfort assessment.Although many advancements have been made,no standardized ML modelling framework exists in daylight assessment.In this study,625 different building layouts were generated to model useful daylight illuminance(UDI).Two state-of-the-art ML algorithms,eXtreme Gradient Boosting(XGBoost)and random forest(RF),were employed to analyze UDI in four categories:UDI-f(fell short),UDI-s(supplementary),UDI-a(autonomous),and UDI-e(exceeded).A feature(internal finish)was introduced to the framework to better reflect real-world representation.The results show that XGBoost models predict UDI with a maximum accuracy of R^(2)=0.992.Compared to RF,the XGBoost ML models can significantly reduce prediction errors.Future research directions have been specified to advance the proposed framework by introducing new features and exploring new ML architectures to standardize ML applications in daylight prediction.

A new energy landscape paving heuristic for satellite module layouts

This article describes a study of the satellite module layout problem （SMLP）, which is a three-dimensional （3D） layout optimization problem with performance constraints that has proved to be non-deterministic polynomial-time hard （NP-hard）. To deal with this problem, we convert it into an unconstrained optimization problem using a quasi-physical strategy and the penalty function method. The energy landscape paving （ELP） method is a class of Monte-Carlo-based global optimization algorithm that has been successfully applied to solve many optimization problems. ELP can search for low-energy layouts via a random walk in complex energy landscapes. However, when ELP falls into the narrow and deep valleys of an energy landscape, it is difficult to escape. By putting forward a new update mechanism of the histogram function in ELP, we obtain an improved ELP method which can overcome this drawback. By incorporating the gradient method with local search into the improved ELP method, a new global search optimization method, hELP, is proposed for SMLP. Two representative instances from the literature are tested. Computational results show that the proposed hELP algorithm is an effective method for solving SMLP with performance constraints.

Effects of urban square entry layouts on spatial ventilation under different surrounding building conditions

Effective urban square ventilation is important for the living comfort and health of residents.This research aims to establish some principles of street entry layouts for urban square ventilation optimization.Using computational fluid dynamics(CFD)simulation techniques,two types of street entry squares(two-intersection and four-intersection)were investigated under the effect of surrounding buildings.Three indices—the spatial mean velocity(<V^(*)>),air change rate(ACH)and mean flow rates()through the street entry and square roof—were calculated to quantify the square ventilation performance.The simulation results indicate that the surrounding buildings could influence the square space ventilation.When the surrounding building conditions change to a building coverage ratio of 0.25,theentering through the street entry can be reduced by 35%,and the<V*>within the square decreases by more than 45%.The optimal street entry layout design depends greatly on the wind direction.When the wind direction is perpendicular to the square street entry,the corner oblique-entry layout square shows a better ventilation performance than the other designs.When the wind direction is oblique to the square street entry,the<V^(*)>declines greatly(up to 68%),and the lateral-entry layout design shows the best ventilation performance.

Two Generative Design Methods of Hospital Operating Department Layouts Based on Healthcare Systematic Layout Planning and Generative Adversarial Network

With the increasing demands of health care,the design of hospital buildings has become increasingly demanding and complicated.However,the traditional layout design method for hospital is labor intensive,time consuming and prone to errors.With the development of artificial intelligence(AI),the intelligent design method has become possible and is considered to be suitable for the layout design of hospital buildings.Two intelli-gent design processes based on healthcare systematic layout planning(HSLP)and generative adversarial network(GAN)are proposed in this paper,which aim to solve the generation problem of the plane functional layout of the operating departments(ODs)of general hospitals.The first design method that is more like a mathemati-cal model with traditional optimization algorithm concerns the following two steps:developing the HSLP model based on the conventional systematic layout planning(SLP)theory,identifying the relationship and flows amongst various departments/units,and arriving at the preliminary plane layout design;establishing mathematical model to optimize the building layout by using the genetic algorithm(GA)to obtain the optimized scheme.The specific process of the second intelligent design based on more than 100 sets of collected OD drawings includes:labelling the corresponding functional layouts of each OD plan;building image-to-image translation with conditional ad-versarial network(pix2pix)for training OD plane layouts,which is one of the most representative GAN models.Finally,the functions and features of the results generated by the two methods are analyzed and compared from an architectural and algorithmic perspective.Comparison of the two design methods shows that the HSLP and GAN models can autonomously generate new OD plane functional layouts.The HSLP layouts have clear functional area adjacencies and optimization goals,but the layouts are relatively rigid and not specific enough.The GAN outputs are the most innovative layouts with strong applicability,but the dataset has strict constraints.The goal of this paper is to help release the heavy load of architects in the early design stage and present the effectiveness of these intelligent design methods in the field of medical architecture.

Influence of yaw damper layouts on locomotive lateral dynamics performance:Pareto optimization and parameter analysis

High-speed locomotives are prone to carbody or bogie hunting when the wheel-rail contact conicity is excessively low or high.This can cause negative impacts on vehicle dynamics performance.This study presents four types of typical yaw damper layouts for a high-speed locomotive(Bo-Bo)and compares,by using the multi-objective optimization method,the influences of those layouts on the lateral dynamics performance of the locomotive;the linear stability indexes under lowconicity and high-conicity conditions are selected as optimization objectives.Furthermore,the radial basis function-based highdimensional model representation(RBF-HDMR)method is used to conduct a global sensitivity analysis(GSA)between key suspension parameters and the lateral dynamics performance of the locomotive,including the lateral ride comfort on straight tracks under the low-conicity condition,and also the operational safety on curved tracks.It is concluded that the layout of yaw dampers has a considerable impact on low-conicity stability and lateral ride comfort but has little influence on curving performance.There is also an important finding that only when the locomotive adopts the layout with opening outward,the difference in lateral ride comfort between the front and rear ends of the carbody can be eliminated by adjusting the lateral installation angle of the yaw dampers.Finally,force analysis and modal analysis methods are adopted to explain the influence mechanism of yaw damper layouts on the lateral stability and differences in lateral ride comfort between the front and rear ends of the carbody.