Developing The Solar Tracking System for Trough Solar Concentrator

The efficiency of the trough solar concentrator strongly depends on the position of its absorber surface with the sun.  Controlling the solar radiation concentrated collectors automatically tracking with the sun plays as the key factor to enhance the energy absorption. An automatic controlling device that can rotating the parabolic trough solar concentrator to the sun is calculated, designed, manufactured, and testing successfully. The experimental results show that the device tracks the sun during the day very well. The sensor has adjusted position of collector good when the intensity of solar radiation changes due to weather

A Planning Experimental Investigation on Tobacco Leaves Dryer Using Paddy Husk and Coal

In Viet Nam, the drying technology and techniques for tobacco leaves is one of the most difficulties and plays as key point to get high economic efficiency in tobacco production. To drying for tobacco leaves of 3,500 hectare, for example in Gia Lai province, there needs about 3000 dryers and there is more than 100,000 cubic meter of wood have been burned for drying which equivalent to more than 300 hectare of forest is deforested annually. A designing and manufacturing study for new tobacco dryer to replace the wood fuel by paddy-husk or coal-wood has been implemented. The results indicate that the new dryer using rice-husk or coal can be replaced for the actual drying system used fire wood with the high quality of tobacco leaves and high efficiency. The planning experimental investigation has found the function of the rate of energy consumption and the quality of drying products successfu

Parametric conditions and exact solution for the Duffing-Van der Pol class of equations

This paper presents a methodology to find the exact solution and respective parametric conditions to the Duffing-Van der Pol class of equations. The supposed method in this paper is different from the Prelle and Singer method and the Lie symmetry method. The main idea of the supposed method is implemented in finding the first integrals of the original equation and leading this equation to a solved equation of lower order to which the exact solution can be obtained. As results the parametric conditions and the exact solutions in parametric forms are indicated. The algorithm for determining integral constants and the investigation of solution characteristics are considered

The Composition of Syngas and Biochar Produced by Gasifier from Viet Nam Rice Husk

Nowadays, biomass has become one of the renewable energy sources might be filled for the lack of energy in the world. Gasification of biomass in general and of rice husk in particularly has attracted many researchers in Viet Nam. The rice husk gasification experimental study has been done with the GEK 20 kW device which is developed by All Power Labs, USA. The air flow rate from 2 to 4 m3/h is applied in gasifier. A portable infra-red syngas analyzer is used for simultaneous measurement the concentrations of CO, CO2, CH4, H2 and O2 of the syngas and for calculation of the heating energy. The effect of air flow rate on temperature, syngas composition, and biochar is analysed and it indicates that the temperature in the combustion area and the content of hydrogen and carbon monoxide in the gas increase when the air-flow rate rises.  In contrast, the yield of biochar is decreased

On the solutions of the Mathieu’s equation

As shown in [1] solutions of the Mathieu’s equation were classified on three fundamental kinds depending mainly on its parameters. These solutions were constructed in the form of infinite series. This paper presents a new approach in which approximated analytical solutions of the Mathieu’s equation are constructed in the finite form. Depending on parameters of Mathieu’s equations general solutions may obtain following behaviors: either bounded almost periodic, or infinitely increased combining with infinitely decreased and or infinitely increased combining with periodic

A Study on a Model of Anchovy Solar

In central and southern coastal areas of Vietnam, annual yield of anchovy is enormous that leads the high demand for anchovy drying. Moreover, seafood in generally and anchovy in particularly brings more benefit for fishermen, especially dried anchovy as an exporting product is one of the main their income. The market requires that anchovy product has to be dried before packaging to export. There are many drying methods to process the anchovy but some problems might need to be solved such as the drying efficiency, the low product quality and sanitation, and the environmental annihilation. In order to using the profuse solar energy, a model for experiment investigation the anchovy dryer has been conducted in ThuDuc district, Hochiminh city with the anchovy caught from Kien giang and Baria-Vung tau province, southern Vietnam. The results indicate that solar energy is one of renewable energy which can be completely used for anchovy drying with high drying efficiency. The dried anchovy has good color, high quality, and especially it passes the requirements of food hygiene and environment protecting

Nonlinear post-buckling of thin FGM annular spherical shells under mechanical loads and resting on elastic foundations

This paper presents an analytical approach to investigate the nonlinear buckling and post-buckling of thin annular spherical shells made of functionally graded materials (FGM) and subjected to mechanical load and resting on Winkler-Pasternak type elastic foundations. Material properties are graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of constituents. Equilibrium and compatibility equations for annular spherical shells are derived by using the classical thin shell theory in terms of the shell deflection and the stress function. Approximate analytical solutions are assumed to satisfy simply supported boundary conditions and Galerkin method is applied to obtain closed-form of load-deflection paths. An analysis is carried out to show the effects of material and geometrical properties and combination of loads on the stability of the annular spherical shells

Postbuckling of functionally graded cylindrical shells based on improved Donnell equations

This paper presents an analytical approach to investigate the buckling and postbuckling of functionally graded cylindrical shells subjected to axial and transversemechanical loads incorporating the effects of temperature. Material properties are assumed to be temperature independent, and graded in the thickness direction accordingto a simple power law distribution in terms of the volume fractions of constituents. Equilibrium equations for perfect cylindrical shells are derived by using improved Donnell shell theory taking into account geometrical nonlinearity. One-term approximate solution is assumed to satisfy simply supported boundary conditions and closed-form expressions of buckling loads and load-deflection curves are determined by Galerkin method. Analysis shows the effects of material and the geometric parameters, buckling mode, pre-existent axial compressive and thermal loads on the nonlinear response of the shells