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  • Intelligent Detection Model Based on a Fully Convolutional Neural Network for Pavement Cracks
  • Abstract The crack is a common pavement failure problem. A lack of periodic maintenance will result in extending the cracks and damage the pavement, which will affect the normal use of the road. Therefore, it is significant to establish an efficient intelligent identification model for pavement cracks. The neural network is a method of simulating animal nervous systems using gradient descent to predict results by learning a weight matrix. It has been widely used in geotechnical engineering, computer vision, medicine, and other fields. However, there are three major problems in the application of neural networks to crack identification. There are too…
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  • Numerical Study on the Gas Leakage and Dispersion at the Street Intersection of a Building Group
  • Abstract Accidents involving natural gas leakage and dispersion pose a significant threat to human life and property. This threat is especially relevant at the street intersection at which dense buildings, heavy traffic flow, and complex underground pipe networks meet. Scholars have conducted numerous studies on gas leakage and dispersion, but investigations of natural gas leakage and dispersion at the street intersection of a building group are not in-depth. In this paper, we presented a three-dimensional (3D) physical model based on the Computational Fluid Dynamic (CFD) methodology to study the natural gas leakage and dispersion at the street intersection of a building…
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  • Study on the Variation Rule of Produced Oil Components during CO2 Flooding in Low Permeability Reservoirs
  • Abstract CO2 flooding has been widely studied and applied to improve oil recovery from low permeability reservoirs. Both the experimental results and the oilfield production data indicate that produced oil components (POC) will vary during CO2 flooding in low permeability reservoirs. However, the present researches fail to explain the variation reason and rule. In this study, the physical model of the POC variation during CO2 flooding in low permeability reservoir was established, and the variation reason and rule were defined. To verify the correctness of the physical model, the interaction rule of the oil-CO2 system was studied by related experiments. The…
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  • Modeling Tracer Flow Characteristics in Different Types of Pores: Visualization and Mathematical Modeling
  • Abstract Structure of porous media and fluid distribution in rocks can significantly affect the transport characteristics during the process of microscale tracer flow. To clarify the effect of micro heterogeneity on aqueous tracer transport, this paper demonstrates microscopic experiments at pore level and proposes an improved mathematical model for tracer transport. The visualization results show a faster tracer movement into movable water than it into bound water, and quicker occupancy in flowing pores than in storage pores caused by the difference of tracer velocity. Moreover, the proposed mathematical model includes the effects of bound water and flowing porosity by applying interstitial…
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  • A New Method of Roughness Construction and Analysis of Construct Parameters
  • Abstract In micro-manufacturing, roughness is unavoidable due to the tolerance of micro-machining methods. Roughness in microchannel could have a significant influence on flow and heat transfer since the size of microchannel is very small. In our work, roughness is modeled as a superposition of waves. A simple Fourier series method is proposed to construct the rough surface. With this method, roughness is constructed on the bottom of the rectangular microchannel which has a hydraulic diameter of 0.5 mm. Two important parameters during roughness construction, triangulate size and correlation length are studied under the same relative roughness 1%. Results show that flow…
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  • Fast Single Image Haze Removal Method for Inhomogeneous Environment Using Variable Scattering Coefficient
  • Abstract The images capture in a bad environment usually loses its fidelity and contrast. As the light rays travel towards its destination they get scattered several times due to the tiny particles of fog and pollutants in the environment, therefore the energy gets lost due to multiple scattering till it arrives its destination, and this degrades the images. So the images taken in bad weather appear in bad quality. Therefore, single image haze removal is quite a bit tough task. Significant research has been done in the haze removal algorithm but in all the techniques, the coefficient of scattering is taken…
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  • Robust Remaining Useful Life Estimation Based on an Improved Unscented Kalman Filtering Method
  • Abstract In the Prognostics and Health Management (PHM), remaining useful life (RUL) is very important and utilized to ensure the reliability and safety of the operation of complex mechanical systems. Recently, unscented Kalman filtering (UKF) has been applied widely in the RUL estimation. For a degradation system, the relationship between its monitored measurements and its degradation states is assumed to be nonlinear in the conventional UKF. However, in some special degradation systems, their monitored measurements have a linear relation with their degradation states. For these special problems, it may bring estimation errors to use the UKF method directly. Besides, many uncertain…
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  • Discrete Circular Distributions with Applications to Shared Orthologs of Paired Circular Genomes
  • Abstract For structural comparisons of paired prokaryotic genomes, an important topic in synthetic and evolutionary biology, the locations of shared orthologous genes (henceforth orthologs) are observed as binned data. This and other data, e.g., wind directions recorded at monitoring sites and intensive care unit arrival times on the 24-hour clock, are counted in binned circular arcs, thus modeling them by discrete circular distributions (DCDs) is required. We propose a novel method to construct a DCD from a base continuous circular distribution (CCD). The probability mass function is defined to take the normalized values of the probability density function at some pre-fixed…
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  • Safety Performance of a Precast Concrete Barrier: Numerical Study
  • Abstract The numerical simulation for a new type of precast concrete barrier for viaducts is carried out systematically. To obtain an accurate representation of the damage state of the concrete barrier under the impact of a vehicle, a stochastic damage-plasticity model of the concrete is adopted in the finite element model. Meanwhile, a simplified mathematical model of the impact between vehicles and the concrete barrier was established and the input energy was converted to the impact load to facilitate the investigation of the safety performance of the concrete barriers. On this basis, a refined finite element (FE) model of a precast…
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  • Comparative Investigation of Two Random Medium Models for Concrete Mesostructure
  • Abstract Concrete is intrinsically endowed with randomness on meso-scale due to the random distribution of aggregates, mortar, etc. In this paper, two random medium models of concrete mesostructure are developed and comparative studies are provided based on random field representation approach. In the first place, concrete is considered as a kind of one-phase random field, where stochastic harmonic function is adopted as the approach to simulate the random field. Secondly, in order to represent the stochastic distribution of the multi-phase of concrete such as aggregates and mortar, two-phase random field based on the Nataf transformation and the Hermite polynomials are introduced.…
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  •   Views:83       Downloads:62        Download PDF
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