Ground Surface Research Articles

Environmental impacts of aerosol radiative effect and urbanization and their interactions over the Beijing-Tianjin-Hebei City cluster

With fast economic development, urban expansion and air pollution are two main eco-environmental challenges confronting China. Though both are associated with intensified human activities, their impacts on urban environment are investigated separately, and the synthetic effect and intricate interaction of the two have not been fully understood. Here, based on in-situ measurements and online-coupled meteorology-chemistry modelling, the impacts of anthropogenic aerosol and urbanization are investigated simultaneously at Beijing-Tianjin-Hebei city cluster during a typical pollution season. The two processes exhibit opposite influences on meteorology and air quality. Aerosol via its radiative effect tends to cause net loss of solar energy with 3 °C cooling at the ground surface and 1 °C warming in the upper boundary layer. In contrast, urbanization yields large increment of net surface solar radiation as well as sensible heat flux, leading to over 1 °C warming in the lower atmosphere. Such modifications of boundary layer structure alter the accumulation and formation of air pollution. Urbanization effect dominated in the modification of near-surface air temperature and air pollution, making the synthetic effect a linear combination of two processes. The study highlights a comprehensive understanding of air pollution and urbanization and their synergy effect on urban environment over megacities.

2D equivalent linear ground response analysis for randomized site profiles

AbstractLocal soil conditions play a crucial role in shaping ground surface responses and impacting the intensity of ground shaking. In this study, the influence of different site profiles on computed ground motion was investigated using a 2D equivalent linear analysis approach. Four distinct site profiles: sand, clay, sand-clay-sand-clay, and clay-sand-clay-sand profiles were considered. The results were presented using multiple metrics, including surface acceleration, displacement, modulus decreasing ratio, and coherence analysis. Notably, the clay profile significantly influenced ground motion, while the sand profile exhibited relatively lower seismic activity. This suggests that softer sites significantly influence ground motion, leading to potentially high levels of shaking.

FORMULATION OF THE OPTIMIZATION PROBLEM FOR UNDERGROUND ENGINEERING NETWORK ROUTES

The article considers the implementation of methods for optimizing underground external engineering networks in order to reduce construction costs. For this purpose, the problem of optimizing the route of such networks is set in the form of a nonlinear programming problem. The route is modeled by a spatial polyline with rectilinear segments, and the coordinates of its vertices are considered design variables. The ground surface in the designated area is modeled as a continuous function of two coordinates in the plan using BIM technologies, which ensures the automated use of topographic information when calculating the volume of earthworks and checking compliance with constraints specified by standards requirements. The main result of the study is the formulation of the problem of optimizing the route of the engineering network taking into account the terrain.

A Case Study of The Performance of A Pile-Supported Bracing Method for Basement Building

Deep excavations in urban areas are highly hazardous due to extensive settling of the surrounding soil, which can lead to the failure of retaining wall systems and the consequent collapse of adjoining properties. The retaining wall and bracing system are important for completing deep excavations for a basement building project. This paper evaluates the performance of an alternative, innovative, low-cost pile-supported bracing system (PSBS) method during excavation for two-level basement construction. Assessed PSBS performance in terms of ground settlement, lateral movement of supporting systems, schedule, and cost comparison. The PSBS excavation method was designed and then implemented to construct a two-level basement using the bottom-up method. The total station was utilized to monitor three-dimensionally, like the adjacent school building, ground surface settlement, and lateral movement of supporting systems. A schedule and cost comparison were performed using internal bracing and the PSBS technique. The recorded filed data was analysed, and it found that the lateral movement of the support system, adjacent building, and ground settlement is within the allowable limit. According to the estimated results, the PSBS method reduces construction time by 272 days compared to the internal bracing system. The PSBS approach is also less expensive than internal bracing for a two-level basement.

Research on complex surface grinding path planning of grinding robot based on NX and Tecnomatix

Research on complex surface grinding path planning of grinding robot based on NX and Tecnomatix

Locomotion analysis of a crawling wave robot in circular canal

In this paper, we analyze the locomotion of a wave robot crawling in a curved canal between rigid walls. We determine the conditions for crawling, considering the robot geometry, orientation, wall curvature, canal width, and friction coefficients. Initially, we present an analytical model of the different cases of crawling and conditions for advancement. We found four cases of crawling: one where the robot touches only the outer wall, two with one contact point each on the outer and inner walls, and a third where the robot has two contact points with the outer wall and one with the inner wall. Subsequently, we introduce a multibody numerical simulation, which accounts for sliding along the wall and over the ground surface. The simulation allows one to validate our analytical results and analyze the robot's behavior under different conditions. Finally, we present validating results of multiple experiments conducted with our SAW robot. This analysis encompasses all types of crawling robots with internal thrust mechanisms that are not based on contact with the side walls of the pipe or canal.

Preference for ground cover when selecting burrow entrances in plateau pikas.

Burrow-dwelling animals such as the plateau pika (Ochotona curzoniae) often seek sturdy entrances for their burrows, which can reduce the need for frequent maintenance. The toughness of the ground surface is often reinforced by the interweaving of plant roots and often varies with the root characteristics. To better understand ground cover preferences when selecting burrow entrances by plateau pikas, we investigated the ratios of different ground covers at the rear of the entrances, as well as their coverage and underlying soil compaction in an undegraded alpine meadow on the Qinghai-Xizang Plateau. The results indicated a clear preference hierarchy of sedges > forbs > grass > bare soil. This distribution was aligned with the soil compaction hierarchy of the topsoil layer beneath each cover type. The sedge coverage was significantly negatively correlated with burrow density, suggesting that plateau pikas opt for sturdy entrances with a natural inclination toward energy conservation. However, there is consensus that the population density of plateau pikas often reaches its maximum on almost nonvegetated "black soil beaches." We hypothesized that the survival benefits brought about by vegetation degradation would be higher than the maintenance costs of burrow entrances.

Optimal Surface Grinding Regression Model Determination with the SRP Method

Optimal Surface Grinding Regression Model Determination with the SRP Method

Improving zirconia ceramics grinding surface integrity through innovative laser bionic surface texturing

Zirconia ceramics have become an important material for the manufacture of key components in aerospace, military, energy, and other fields due to their excellent mechanical properties. However, their inherent high hardness and brittleness make them difficult to machine with high efficiency and low damage, resulting in poor surface integrity. Inspired by the ribbed groove structure of shark skin and the fractal structure of insect wing veins, two zirconia ceramics with different bionic textures are designed in this paper, and zirconia ceramic surfaces are bionically textured by using an ultrafast picosecond pulse laser. The effects of the special bionic textures on the grinding behavior of zirconia ceramics, specifically surface morphology, surface roughness, edge morphology, and subsurface damage, were investigated. The experimental results show that the surface integrity of the bionic textured zirconia ceramics is better compared to the untextured surface. In particular, the bionic insect wing veins texture exhibits the best surface quality with the least sub-surface damage, and the surface roughness Sa is reduced by a maximum of 21.46 %, and Sz is reduced by a maximum of 18.87 %. However, the best edge morphology is exhibited by the bionic shark skin texture. Additionally, bionic texturing improves grinding lubrication and cooling conditions. The results confirm that applying bionic texturing to zirconia ceramics effectively enhances grinding performance and improves grinding surface integrity.

Design and Fabrication of Friction Floor Cleaner for Cattle Shed

Abstract: In the world of advanced technology and scientific evolution our one vision should be there in the health and hygiene of domestic animals. Domestic animals like cows and goats are the source of revenue in the form of milk. Hence it is essential to take care of the health and hygiene of cows as unhygienic surroundings may lead to various diseases among the cattle and can also affect productivity. There also lies the probability of diseases being transmitted to human beings who consume this milk. So considering all these factors we aim to design and fabricate a machine for the cleaning of cowshed. The proposed system uses 4 different arrangements which are friction cleaning arrangement, water distribution arrangement, disinfectant spraying arrangement, and left and right (1-D) movement arrangement of the complete system. The friction cleaning system uses a rotating brush arrangement to make the complete ground surface of cowsheds dirt-free. A watering arrangement is used to distribute water on the ground surface. Disinfectant distribution arrangement uses sprinkler arrangement to distribute disinfectant to make cowshed bacteria-free. 1-D movement arrangement uses rack and pinion arrangement to make the complete system move in one-directional movement

Assessment of microbial properties, and heavy metals contents of surface water and ground water samples In Ureje and Ireje, Ekiti State, Nigeria.

Water is everywhere, · it is the most basic and necessary element of life, as well as the most important and abundant compound in the ecosystem. Standard methods were used to evaluate the physicochemical properties, microbial properties, and heavy metal content of river and well water samples in Ekiti State, South-West Nigeria. Important parameter like pH, electrical conductivity, total dissolved solids, DO, BOD, turbidity, total alkalinity, total hardness, heavy metals and microbial properties are determined. The research work indicated that temperature, odour, pH, alkalinity, TDS, biochemical oxygen demand, DO, chloride, nitrate and turbidity were within the range of WHO permissible limits for drinking water while color, Conductivity, iron and manganese were above the WHO permissible limits. The study also indicated that the microbial contents such as total viable count, yeast/mold and coliform were above the WHO permissible limits for drinking. These results show that the water sources were slightly contaminated and unsafe for human consumption. This water must be treated before it may be consumed or used for domestic application.

Investigation on Grindability Improvement of Inconel 625 using Multi-walled Carbon Nanotubes Nanofluids-Assisted Minimum Quantity Lubrication Surface Grinding

Investigation on Grindability Improvement of Inconel 625 using Multi-walled Carbon Nanotubes Nanofluids-Assisted Minimum Quantity Lubrication Surface Grinding

A Dual-Layer Complex Network-Based Quantitative Flood Vulnerability Assessment Method of Transportation Systems

Evaluating the vulnerability of urban transportation systems to flood disasters can provide scientific support for urban disaster prevention and mitigation. Current methods for assessing the flood vulnerability of urban roads often overlook the internal relationships within the complex spatial composition of road networks and surface structures. In this study, based on the theory of complex networks, a dual-layer network assessment model is established for evaluating the flood vulnerability of urban transportation systems by coupling basic geographic data with road network vector data. Unlike traditional methods, this model considers the complex relationship between road network structures and ground surfaces, uncovering a correlation between road network structure and road flood vulnerability. By utilizing this model, the flood vulnerability of road networks in Shenzhen, as well as the city’s spatial flood vulnerability, are quantitatively assessed. Based on the quantitative results, we create maps illustrating the distribution of road and spatial flood vulnerability in Shenzhen. The study results reflect that roads highly vulnerable to flooding are mainly located in the central urban area of the southwest, with the flood vulnerability spatially concentrated primarily in the northern and western regions. Using data from government reports, news stories, and other sources over the past five years, we compile recorded instances of urban waterlogging. The quantitative results of the model are consistent with the distribution trend in recorded waterlogging points, indicating that the model’s outcomes are authentic and reliable.

Response Comparisons of Prefabricated and Cast-in-Place Subway Station Structures in Liquefiable Soil Foundation with the Ground Surface Slight Inclined

In recent years, the prefabricated subway station structure (PSSS) has become a hot spot of underground structure research. In this paper, the numerical model of a soil–subway station structure in a slowly inclined liquefiable site at the surface is established by using FLAC3D finite difference software. And the applicability of the PSSS under the gently inclined liquefiable site is investigated through the foundation pore water pressure, lateral movement of liquefied soil, and dynamic response and uplift characteristics of the subway station structure. It is found that under the gently inclined liquefiable site conditions, the PSSS exhibits tilting and floating behaviors and has an anti-liquefaction effect within a certain range of surrounding soil layers. Compared with the same type of cast-in-place subway station structure (CIPSSS), it has better resistance to overturning and uplift, and the structure has less stress. Under the premise of ensuring static waterproofing, the PSSS can be applied to surface inclined liquefiable sites.

BAYESIAN NEURAL NETWORK RAINFALL MODELLING: A CASE STUDY IN EAST JAVA

Rainfall is an important parameter in meteorology and hydrology, and it measures the amount of rain that falls from the atmosphere to the ground surface in liquid form. However, in the process of measuring rainfall, changes in the rainfall cycle sometimes occur due to climate change, global warming, and other factors. Therefore, this research aims to model daily rainfall using the Bayesian Neural Network (BNN) approach, combining the Bayesian Method and Artificial Neural Network (ANN). ANN is suitable for rainfall models that have intermittent characteristics. Meanwhile, the Bayesian method provides advantages in producing model parameter inferences that provide uncertainty measurements in predictions. BNN is expected to deliver better daily rainfall predictions than ANN. This research used daily rainfall data in East Jawa, and the results show that the Bayesian Neural Network produces better rainfall predictions when describing rainfall in East Java. These predictions will be very useful for the government and the people of East Java province to prevent flooding. Also, with rainfall predictions, people will know more about what crops should be planted during the rains.

Modelling air, ground surface and permafrost temperature variability across four dissimilar valleys, Yukon, Canada

Spatial maps of the air and ground thermal regime were generated for four Yukon valleys. The aim was to model air, ground surface and ground temperature (at fine spatial resolution) using locally measured inverted surface lapse rates (SLR), to better predict temperature along an elevation gradient. These local models were then compared to a regional permafrost probability model, which utilized differing inversion assumptions, as well as circumpolar and national models generated without considering inversions. Overall, permafrost probability in the regional model matched well with the local models where assumptions of treeline and inverted SLRs held true. When normal SLRs were assumed, permafrost presence was overestimated in each valley. This discrepancy was greatest at high elevations where permafrost was predicted to be coldest and most widespread. However, the difference between valleys was dependent on surface and subsurface characteristics such as higher snow cover, mature forest or thick organic layers showed a greater disassociation from the air temperature overall. Appropriate characterization of the SLR is essential for accurate predictions of the ground thermal regime’s spatial distribution and permafrost presence. These models also provide a starting point for better predictions of warming in these valleys and other areas subject to inversions of similar magnitudes.

Changes in leaf area index by tropical forest transformation to plantations increase below-canopy surface temperatures

Climate change affects life in tropical landscapes by increasing temperatures, among other impacts. In addition, land transformation from forest to other land cover types typically increases temperatures of surfaces exposed to direct solar radiation. In rural areas, however, many organisms including humans live sheltered below canopies, but little is known about below-canopy surface temperatures. We assessed canopy leaf area index (LAI) and below-canopy surface temperatures in a landscape of rural lowland Sumatra, Indonesia. In this region, land-use trajectories in the past decades led from forest to monocultural plantations. We found that LAI varied more than 10-fold, with the highest values observed in forest and low values in rubber and oil palm plantations. Below-canopy surface temperatures increased significantly with decreasing LAI. A decrease in LAI by one unit (m2 leaf area per m2 ground area) increased ground surface temperature by 0.95 °C (confidence interval: 1.07–0.83 °C) around noon. Likewise, the temperatures measured on peoples’ cap or hijab surfaces under the canopy was strongly affected. For a light-brown hijab, the average noon surface temperature increased by 4.0 °C from forest to oil palm. Thus, in addition to climate warming, land transformation and associated declines in canopy LAI significantly increased below-canopy surface temperatures. Strategies for mitigating such potentially adverse temperature effects may include the integration of more and densely foliated trees into landscapes.

Model test on cooling performance of a new method for mitigating permafrost thaw around buried oil pipeline

Buried pipelines have been widely used to transport petroleum-based products over long distances in permafrost regions. Field observations reveal that they are endangered by rapid permafrost thawing and resulting massive soil movements, despite adopting some measures to protect pipeline foundation permafrost. A new mitigation technique is proposed to slow down the permafrost thawing ulteriorly. With this technique, a seasonal air-cooled embankment (SACE), mainly composed of a crushed rock layer, supports the pipeline and transfers the heat from the pipeline to ambient air in the cold seasons. A scale model test with the controlled air and oil temperatures was carried out to evaluate the proposed measure. The temperature and volumetric unfrozen water content of the permafrost subgrade beneath both the SACE and the direct-buried pipeline, as well as ground surface displacements, were measured during the whole testing process. A comparison of the hydrothermal process of the subgrade permafrost under the SACE and the direct-buried warm pipeline indicates that the proposed measure can substantially mitigate the rapid thawing of permafrost by controlling the geothermal regimes of the pipeline.

Surface Roughness Model of Ground 4H-SiC Considering Ductile and Brittle Removal

Abstract Surface roughness is a critical indicator to evaluate the quality of 4H-SiC grinding surfaces. Determining surface roughness experimentally is a time-consuming and laborious process, and developing a reliable model for predicting surface roughness is a key challenge in 4H-SiC grinding. However, the existing models for surface roughness in wafer rotational grinding fail to yield reasonable results because they do not adequately consider the processing parameters and material characteristics. In this study, we proposed a new analytical model for predicting surface roughness in 4H-SiC wafer rotational grinding, which comprehensively incorporates the grinding conditions and material characteristics of brittle substrate. This model derives and calculates the material's elastic recovery coefficient based on contact mechanics and elastic contact theory. Subsequently, we modified the grain depth-of-cut model by incorporating elastic recovery coefficient. Additionally, we analyze the distribution of the failure mode (ductile or brittle) on the surface of a material when the depth at which the material is cut instead follows a random distribution known as the Rayleigh distribution. To validate the accuracy of the established model, a series of grinding experiments are conducted using various grain depth-of-cut to produce 4H-SiC wafers with different surface roughness values. These results are then compared with those predicted by both this model and the traditional model. The findings demonstrate that the calculated data obtained from the proposed model exhibit better agreement with the measured data. This research addresses the need for an improved surface roughness model in 4H-SiC wafer rotational grinding.

Variability in receivers responses of MASW test on undulated grounds: A numerical perspective

This article presents methodological and signal processing cautions associated with utilizing the multichannel analysis of surface waves (MASW) test for determining shear wave velocity (Vs) profiles on undulated ground surfaces. The past studies highlight that the conventional MASW test, which is suitable for flat ground surfaces, may not directly apply to undulated grounds with features like heave, crest, etc. Previous studies on MASW test lack an understanding of the influence of source and receiver positioning on various undulations. Three scenarios of ground undulations were created in GiD software and analyzed in the OpenSEES software framework. There were 12 receivers used for these ground undulations based on the Fourier amplitude spectrum attenuation. The receivers' responses (horizontal and vertical components of wavefields) from these ground undulations were analyzed through signal processing using cross-correlation, time-lag, and wavelet coherence. Notably, the undulated topography significantly impacted the vertical components of the wavefield. The phase angle variations from wavelet coherence could be used to determine the minimum frequency of the dispersion curve for these ground undulations. Significant variations in the phase velocity were observed at lower frequencies in the presence of ground undulations, while on a flat surface, they remained unaffected. The effect of under−/over-estimation of Vs (in the range of 50–100 m/s) was successfully demonstrated in each respective undulation with the methodological and processing cautions needed in the MASW analysis.