Soil moisture migration model based on Flux-concentration relation under steady rainfall

Moisture content distribution in soil is of great importance for understanding rainfall-induced slope failure and roadbed settlement. This study aims to develop a moisture migration model that improves the quantification of moisture content at an arbitrary point of the soil at any time for the whole process of infiltration under steady rainfall. The model was derived from the Richards' equation using the Flux-concentration relation, which was validated by numerical solutions calculated by Hydrus-1D software to evaluate the performance of the model. Results showed good accuracy and high adaptability for the moisture migration simulation of a wide range of soil types, and is applicable for short-duration and long-duration steady rainfall. Moreover, it can also reflect the stratification phenomenon for soil profile wetting by infiltration. Our analysis indicates that the flux and surface volumetric moisture content together can bound the boundary conditions of rainfall infiltration, which presents a shift from constant-flux to constant-concentration during a long-duration steady rainfall. The migration rate of the wetting front in the later stage of infiltration positively correlates with rainfall intensity under the constant-flux condition, while it finally stabilizes at Ks/(θs − θi) under the constant-concentration condition (i.e., Ks-saturated hydraulic conductivity, θs-saturated volumetric moisture content, θi-initial volumetric moisture content). HIGHLIGHT Moisture migration model was derived to improve the quantification of moisture content at an arbitrary point of the soil at any time for the whole process of infiltration under steady rainfall, which shows good accuracy and high adaptability for the moisture migration simulation of a wide range of soil types, and is applicable for short-duration and long-duration steady rainfall.

Design Development and Analysis of a Partially Superconducting Axial Flux Motor Using YBCO Bulks

In this work, authors have designed, constructed and tested a new kind of partially superconducting axial flux machine. This model is based on the magnetic flux concentration principle. The magnetic field creation part consists of the NbTi superconducting solenoid and two YBaCuO plates. A theoretical study is conducted of an extrapolated superconducting inductor for low-temperature superconducting and high-temperature superconducting solenoids. The optimization of the inductor is carried out in order to increase the torque and the power density as well. This improvement is done by changing the shape of the elements which form the superconducting inductor. Finally, a prototype is realized, and tested.

An influence of slag refining on the structure and mechanical properties of the brass CuZn39Pb2

The results presented in the dissertation show the influence of a kind and concentration of the flux added during the process of the lead brass smelting on its structure, chemical composition and mechanical properties—hardness and strength. A positive refining, structure, mechanical properties, brass influence of the refining and modification process manifested in an improvement of mechanical properties as well as an increase of the structure, chemical composition and mechanical properties homogeneity in the entire volume of the ingot has been proven. The influence of the flux concentration on the structure and mechanical properties of the alloy was determined. The optimal flux concentration improving the tested properties was established.

Theoretical investigations into magnetorheological finishing of external cylindrical surfaces for improved performance

Fine finishing entails increased percentage contact area, less friction, and less wear. The magnetorheological finishing is a precision process to obtain the fine finishing on the workpiece surface for improved functional applications. So, the rotary rectangular core-based magnetorheological finishing process is utilized for the precise finishing of the cylindrical external surfaces. The rotary-rectangular shaped tool core tip surface provides the uniformly magnetic flux concentration that further benefit to offer the uniform fine finishing on the cylindrical work-part's external surface. In this work, a theoretical model is developed to predict the reduction in the surface asperities during the magnetorheological finishing of the external cylindrical surfaces. The rotational speed of the rectangular tool core on the rotating cylindrical work-part enhances the relative speed of active abrasives, which decreases the pitch, helix angle, and increases the helical path length. These results enhance the uniform precise finishing on the cylindrical work-parts and also enhances the process performance. For validation of the theoretical roughness model, the experiments have been performed on the cylindrical external surface of the H13 die steel workpiece. The percentage error between the experimentally obtained Ra value and theoretical Ra value is found to be −4.76% to 3.06%, which shows the good agreement between the theoretical model and experimental results. It also shows the practicality and accuracy of the present process while finishing the H13 die steel and it is useful for many industrial applications.

Finite formulation for the computation of sorptivity

<p>Soil sorptivity is one of the key hydraulic parameters for modelling water infiltration into soil. It quantifies the capacity of a soil to infiltrate water by capillarity. Several formulations, based on various models, have been proposed to compute it from the water retention and the unsaturated hydraulic conductivity functions. All these formulations use the integration of the product of either the hydraulic conductivity or diffusivity function with the flux concentration function. The integration can be performed either over an interval of water pressure head or water content, yielding two equal values. However, the expression of the integral as a function of water pressure head may involve a huge or even infinite interval, which can be numerically difficult to handle. In opposite, the expression of the integral as a function of water content involves the integration of a diverging function (diffusivity) over a large interval, which is also troublesome from a numerical point of view. In this paper, we provide a new expression for sorptivity by cutting the integral in two parts, in order to involve only the integration of a finite function over a finite interval. The dependency of the integral on the flux concentration function is also investigated.</p>

Significant power enhancement of magneto-mechano-electric generators by magnetic flux concentration

A magneto-mechano-electric (MME) generator comprising a magnetoelectric (ME) composite and magnetic flux concentrator (MFC) can effectively harvest the tiny magnetic noise to power the autonomous internet of things (IoT) sensor networks.