Design and simulation analysis of cowpea dehulling Machine

The dehulling of cowpea seeds will have a great influence in increasing the overall production, consumption, processing into more dietary, hygienic products and the advancement of cowpea processing industry. The technology of cowpea processing industry is still at its lowest ebb. Therefore, designing a machine to dehull cowpea beans would be of greater benefit to the common man protein intake and the afore-mentioned development of the cowpea industry. The machine is designed to be mechanically operated by an electric motor as the prime mover with dehulling capacity of 6.67x10-4m3/s or 37.2kg/min. The beans will be fed by rotating force received from the feed wheel in the hopper into the plate's gap interface that will be pre-set that the total volume of feeder is approximately the volume of the space between plate surfaces. The rotating action of moving against stationary plate effect the rasping of soaked cowpea off their cotyledons. The design consideration applied appropriate technology, ease of dehulling soaked cowpea and the attrition action of plate surfaces and readily available engineering materials with possible equipment in the country. The dehulled efficiency was 79% at 81.25% machine efficiency shown from the simulation analysis, this greatly show a high level improvement when compared with other related designs.

Numerical investigation of turbulent offset jet flow over a moving flat plate using low-Reynolds number turbulence model

The present study reports the numerical simulation of turbulent plane offset jet flow over a moving plate. The effect of plate velocity on various flow characteristics are discussed in detail including the special case of a stationary plate. For turbulence closure, low-Reynolds number (LRN) model proposed by Yang and Shih (YS) is applied because it is computationally robust and reported to perform well in many complex flow situations. The computations have been carried out with a Reynolds number of 15000 for various offset ratios (OR=3, 7 and 11) for plate to jet velocity ratios in the range 0-2. Finite volume method with a staggered grid arrangement has been used to solve the transport equations. The application of LRN model along with integration to wall approach enables to capture one closed loop of Moffatt vortex near the left corner of the wall for the stationary plate case. The spreading of jet has been found to reduce with increase in the plate velocity. The jet half-width lies very close to the wall for the plate to jet velocity 1.5 and 2. For two extreme limits of plate velocity i.e. Uplate = 0 and 2, the nearly self-similar profiles are observed at different axial locations in the wall jet region. Also, the flow is observed to exhibit nearly self-similar behavior when velocity profiles are plotted for various offset ratios at a given axial location in the wall jet region for Uplate = 0 and 2.

Interaction of a mantle plume and a moving plate: insights from numerical modeling

<p>The impingement of a hot buoyant mantle plume onto the lithosphere can result in either breaking of the lithosphere, which might results in subduction initiation or in under-plating of the plume beneath the lithosphere. Key natural examples of the former and latter are formation of subduction along the southern margin of Caribbean and northwestern South America in the late Cretaceous as well as the hotspot chains of Hawaii, respectively. In previous studies the interaction of a buoyant mantle plume with lithosphere was investigated either for the case of stationary lithosphere or for moving lithosphere but ignoring the effect of magmatic weakening of the lithosphere above the plume head. In this study we aim to investigate the response of a moving lithosphere to the arrival of a stationary mantle plume including the effect of magmatic lithospheric weakening. To do so we use 3d thermo-mechanical models employing the finite difference code I3ELVIS. Our setup consists of an oceanic lithosphere, mantle plume and asthenosphere till depth of 400 km. The moving plate is simulated by imposing a kinematic boundary condition on the lithospheric part of the side boundaries. The mantle plume in our models has a mushroom shape. The experiments differ in the age of the lithosphere, rate of the plate motion and size of the mantle plume. For different combinations of these parameters model results show either (1) breaking of the lithosphere and initiation of subduction above the plume head or (2) asymmetric spreading of the plume material below the lithosphere without large deformation of the lithosphere. We find that the critical radius of the plume that breaks the lithosphere and initiates subduction depends on plume buoyancy and the lithospheric age, but not on the plate speed. In general, the modeling results for the moving plate are similar to the results for a stationary plate, but the shapes of the region of the deformed lithosphere differ.</p>

The Evolution and Testing of Aerial Lift Anti-Entrapment Safety Devices

First introduced in the 1950’s [2], aerial lifts, also known as cherry pickers, aerial work platforms, and boom lifts, have enabled workers to perform tasks at elevated heights much easier. In many applications with overhead obstructions however, these lifts also present a severe risk to the users, often including fatality. The user can become entrapped due to unintentional involvement with overhead obstacles and be crushed between the lift and the obstacle. In this paper, we present the evolution of the common safety features and anti-entrapment devices that have been developed in response to the growing awareness of the prevalence of these injuries. After these devices are discussed, results are shown for experimental testing of potential crush mechanisms and representative forces. To test the crush force, load cells are attached to a stationary plate in front of a test dummy and forces are recorded to evaluate potential entrapment scenarios. Representative safety device designs are tested, which include mechanical, electrical, and audible features to stop and/or reverse the direction of movement to mitigate or prevent injury. All tests show that having an anti-entrapment device installed drastically reduces the risk to the user and likely prevents fatalities.

Numerical Analysis of Flow Characteristics of Jeffery Nanofluid Past a Moving Plate in Conducting Field

This paper reveals the physical properties of Jeffery nanofluid flow past a moving plate embedded in porous medium under the existence of radiation and thermal diffusion. The analysis is carried out in three cases of moving plate, namely stationary plate λ = 0, forth-moving plate λ = 1, back-moving plate λ = −1. Finite difference method is applied to solve the governing equations of the flow and pointed out the variations in velocity, temperature and concentration with the use of graphical presentations. The impact of several parameters on local skin friction, Nusselt number and Sherwood number is also noticed and discussed. Enhancement of velocity is observed under the impact of Jeffery parameter for the cases of stationary plate and back-moving plate, whereas reverse nature is found in the case of forth-moving plate. The velocity enhances as the values of porosity parameter increases for the case of stationary plate and forth-moving plate but a reverse nature is noticed in the case of back-moving plate.

HOMOGENIZATION OF ELASTIC PLATE EQUATION∗

We are interested in general homogenization theory for fourth-order elliptic equation describing the Kirchhoff model for pure bending of a thin solid symmetric plate under a transverse load. Such theory is well-developed for second-order elliptic problems, while some results for general elliptic equations were established by Zhikov, Kozlov, Oleinik and Ngoan (1979). We push forward an approach of Antoni´c and Balenovi´c (1999, 2000) by proving a number of properties of H-convergence for stationary plate equation.

The Effect of MHD on Free Convection with Periodic Temperature and Concentration in the Presence of Thermal Radiation and Chemical Reaction

This paper studies the effect of magneto hydrodynamics on unsteady free convection between a pair of infinite vertical Couette plates. The temperature of the plates and concentration between the plates vary with time. Convection between the plates is considered in the presence of thermal radiation and chemical reaction. The solution is obtained using perturbation techniques. These techniques are used to transform nonlinear coupled partial differential equations to a system of ordinary differential equations. The resulting equations are solved analytically. The solution is expressed in terms of power series with some small parameter. The effect of various parameters, viz., velocity, temperature and concentration, has been discussed. Mat lab code simulation study is carried out to support the theoretical results. The result shows that as the thermal radiation parameter R increases, the temperature decreases near the moving porous plate while it approaches to a zero in the region close to the boundary layer of the stationary plate. Moreover, as the modified Grashof number, i.e., based on concentration difference, increases, the velocity of the fluid flow increases hence the concentration decreases. An increase in both the chemical reaction parameter and Schmidt number results in decreased concentration.