Evaluating the impact of tunnelling on surface-water resources: update of the Drawdown Hazard Index (DHI) method

Potential climate change impacts on groundwater resources of south-western Australia

The paper presents the results of analytical and numerical model calculations of elastic surface displacements caused by earthquakes and the processes of earthquake nucleation. The analytical calculations are focused on the model of a homogeneous elastic space; the numerical calculations also cover models of radially inhomogeneous distributions of elastic moduli in the crust and upper mantle described by the PREM model.

The present study proposes an integrated simulation–optimization framework to assess environmental flow by mitigating environmental impacts on the surface and ground water resources. The model satisfies water demand using surface water resources (rivers) and ground water resources (wells). The outputs of the ecological simulation blocks of river ecosystem and the ground water level simulation were utilized in a multiobjective optimization model in which six objectives were considered in the optimization model including (1) minimizing losses of water supply (2) minimizing physical fish habitat losses simulated by fuzzy approach (3) minimizing spawning habitat losses (4) minimizing ground water level deterioration simulated by adaptive neuro fuzzy inference system(ANFIS) (5) maximizing macroinvertebrates population simulated by ANFIS (6) minimizing physical macrophytes habitat losses. Based on the results in the case study, ANFIS-based model is robust for simulating key factors such as water quality and macroinvertebrate’s population. The results demonstrate the reliability and robustness of the proposed method to balance environmental requirements and water supply. The optimization model increased the percentage of environmental flow in the drought years considerably. It supplies 69% of water demand in normal years, while the environmental impacts on the river ecosystem are minimized. The proposed model balances the portion of using surface water and ground water in water supply considering environmental impacts on both sources. Using the proposed method is recommendable for optimal environmental management of surface water and ground water in river basin scale.

Poor fragmentation, oversize and undersize, means economic loss and as a consequence, putting the whole mining operation at risk. Risk assessment prior to blasting operation can be a helpful tool for total cost reduction. In this paper, a new model, considering all pertinent parameters is proposed to predict the risk due to poor fragmentation in rock blasting, using the concept of Rock Engineering Systems (RES) with interaction matrix. The principles of RES were used to define an index, the so called vulnerability index (VI), describing the risk condition due to poor fragmentation.

Calculations on temperature distributions in a multilayer thin-film stack of a disk as used in optical recording are discussed. It is shown that an analytical solution of the heat equations can be obtained if certain realistic approximations are applied. The analytical solution is compared with numerical calculations on the heat equations, and for the cases investigated, a good agreement is obtained: If the active layer of an optical disk has a high(er) diffusivity with respect to the protective layer and the substrate, the analytical expressions obtained predict maximum temperatures in the active layer, correct to within a few percent, and accurate trends for a variety of problems. Results of numerical and analytical calculations are shown in detail for a realistic magneto-optical thin-film stack, and some general trends are discussed. If only the temperature distribution in the active layer is of interest, an enormous reduction of the calculation time can be achieved, important in write-strategy calculations, for instance.

Microscopic yielding of CF/epoxy composites and the effect on the formation of thermal residual stresses

In a nuclear industry area, high temperature treatment of materials is a factor which requires special attention. Assessment needs to be conducted on the properties of the materials used, including the strength of the materials. The measurement of material properties under thermal processes may reflect residual stresses. The use of Genetic Algorithm (GA) to determine the optimal residual stress is one way to determine the strength of a material. In residual stress modeling with several parameters, it is sometimes difficult to solve for the optimal value through analytical or numerical calculations. Here, GA is an efficient algorithm which can generate the optimal values, both minima and maxima. The purposes of this research are to obtain the optimization of variable in residual stress models using GA and to predict the center of residual stress distribution, using fuzzy neural network (FNN) while the artificial neural network (ANN) used for modeling. In this work a single-material 316/316L stainless steel bar is modeled. The minimal residual stresses of the material at high temperatures were obtained with GA and analytical calculations. At a temperature of 650 0 C, t he GA optimal residual stress estimation converged at – 711.3689 MPa at adistance of 0.002934 mm from center point, whereas the analytical calculation result at that temperature and position is -975.556 MPa . At a temperature of 850 0 C, the GA result was -969.868 MPa at 0.002757 mm from the center point, while with analytical result was -1061.13 MPa. The difference in residual stress between GA and analytical results at a temperature of 650 0 C is about 27 %, while at 850 0 C it is 8.67 %. The distribution of residual stress showed a grouping concentrated around a coordinate of (-76; 76) MPa. The residuals stress model is a degree-two polynomial with coefficients of 50.33, -76.54, and -55.2, respectively, with a standard deviation of 7.874 . Received: 09 October 2014 ; Revised: 21 April 2015; Accepted: 16 June 2015

Analytical and numerical calculations of limiting characteristics of electromagnetic radiation detectors based on Josephson junctions are carried out. Josephson junctions are described by a simple resistively shunted model and their Josephson energy is considered to be comparable to the energy of thermal fluctuations. The operation modes of such junctions as a classical detector using ac rectification on a static nonlinear current–voltage characteristic are established. The results of numerical and analytical calculations are compared, and it is shown that the classical detection mode can be analyzed and optimized using the derived analytical expressions for the main limiting characteristics. The study demonstrates the possibility of achieving a limiting sensitivity up to 2 × 10–15 W/Hz1/2, a dynamic power range of 105–106, and a spectral range up to 1.4 THz, in a temperature range 50–77 K using new Josephson thin-film junctions consisting of high-temperature YBa2Cu3O7 – x superconductors with mutually tilted c axes.

We study how stably stratified or semi-convective layers alter the tidal dissipation rates associated with the generation of internal waves in planetary interiors. We consider if these layers could contribute to the high rates of tidal dissipation observed for Jupiter and Saturn in our solar system. We use an idealized global spherical Boussinesq model to study the influence of stable stratification and semi-convective layers on tidal dissipation rates. We carry out analytical and numerical calculations considering realistic tidal forcing and measure how the viscous and thermal dissipation rates depend on the parameters relating to the internal stratification profile. We find that the strongly frequency-dependent tidal dissipation rate is highly dependent on the parameters relating to the stable stratification, with strong resonant peaks that align with the internal modes of the system. The locations and sizes of these resonances depend on the form and parameters of the stratification, which we explore both analytically and numerically. Our results suggest that stable stratification can significantly enhance the tidal dissipation in particular frequency ranges. Analytical calculations in the low-frequency regime give us scaling laws for the key parameters, including the tidal quality factor due to internal gravity waves. Stably stratified layers can significantly contribute to tidal dissipation in solar and extrasolar giant planets, and we estimate substantial tidal evolution for hot Neptunes. Further investigation is needed to robustly quantify the significance of the contribution in realistic interior models, and to consider the contribution of inertial waves.

Two computer programs which solve the partial differential equations for sound propagation numerically are applied to the study of problems in acoustic emission. The programs use finite difference and finite element techniques to calculate sound fields due to distributions of sources in complex geometries in two dimensions. The potential to handle more complex geometries and to model more realistic sources is the main advantage of these numerical calculations over the analytic calculations. The main disadvantage of the numerical techniques is the cost of obtaining results since a large main frame computer or supercomputer is required. Both numerical methods are found to agree well with analytic calculations using Green's functions. The finite difference method agrees very well with the analytic calculations but, in its current implementation, is much slower and contains more numerical noise compared to the finite element method. The finite element method has the additional advantage of being capable of handling more complex geometries than the finite difference method.

Generation of internal tides in an ocean of finite depth: analytical and numerical calculations

Stress field is an important parameter for determining the strength of a plate due the loading. Measurement of the stress field in it cannot be done directly. The mathematic explanation shows that the stress field has a relationship with the terrain displacement/displacement. In the plate theory, deflection is defined as displacement towards out plane direction. One method to get the value of deflection on the plate is a moire method. This moire method uses the principle of line superposition between plate and its reference. When a test plate subjected to a load, the deflection that occurs in the test material a pattern will be produced in the form of a superposition of light and dark pattern (fringe) which describes the distribution of the stress-displacement on a surface of tested material. Tested material is AISI 304.The surface of tested material was given a lattice pattern with variations in distance of 1 mm. The fourth side of the tested plate is clamped perfectly, then the center of it will be pressurized with variations in displacement (0.5, 1, 1.5, and 2 mm). The occurred Moire patterns will be captured by the camera to turn it into a digital image. Furthermore, it will be processed through a series of image processing which consists of the four different filter algorithms (Gaussian filter and Butterworth Low Pass Filter), and also four edge detection algorithms (Sobel, Prewitt, Canny, and Roberts).The results of the stress-strain measurements will be compared with the results of analytical calculations and numerical calculations. The difference of displacement average using ​​moire method compared with analytical method is 6.75%, while using numerical method is 7.55%. Furthermore the difference of stress average using ​​moire method compared with analytical calculation is 9:08%, while using numerical methods by 9.5%.

Using a combination of numerical and analytical calculations, we study the disorder-induced zero bias anomaly (ZBA) in the density of states of strongly-correlated systems modeled by the two dimensional Anderson-Hubbard model. We find that the ZBA comes from the response of the nonlocal inelastic self-energy to the disorder potential, a result which has implications for theoretical approaches that retain only the local self-energy. Using an approximate analytic form for the self-energy, we derive an expression for the density of states of the two-site Anderson-Hubbard model. Our formalism reproduces the essential features of the ZBA, namely that the width is proportional to the hopping amplitude $t$ and is independent of the interaction strength and disorder potential.

Exploring Third-Order Chromatic Aberrations of Electron Lenses with Computer Algebra

With the Rock Engineering Systems (RES) methodology, rock mechanics and rock engineering problems are studied systematically using a total systems approach, incorporating rock mass properties, interrelated parameters, complex interaction mechanisms and dynamic behavioral modes. In this paper, a method of implementation and computerization of RES is considered, using neural networks together with an expert system. The computerized RES starts with the data processing of rock mass properties and boundary conditions and data base management of rock engineering case records. This step is followed by building and operating parameter interaction matrices with the combined use of backpropagation networks and an expert system. Finally, a simulator for modelling the dynamic process of rock engineering systems using the Hopfield network is incorporated. With the aid of neural networks' learning capability and expert system's symbol-reasoning capability, the RES approach is implemented in an “intelligent” mode.