Nakhon Ratchasima, Thailand
Nakhon Ratchasima, Thailand

Vongchavalitkul University is a private university located in Nakhon Ratchasima, Thailand. Founded in 1984 as Vongchavalitkul College, it was upgraded to a university status in 1994. Currently the university offers 26 undergraduate degree programs, 5 masters degree programs, and 4 doctoral degree programs. Wikipedia.


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Uchaipichat A.,Vongchavalitkul University
Electronic Journal of Geotechnical Engineering | Year: 2010

Influence of temperature on soil behavior has become an interesting subject in geotechnical engineering area. Generally a thermal effect causes a reduction in strength under undrained condition. Thus, this research is aimed at studying the possibility of the use of cement to improve the soil strength under elevated temperature. A series of unconfined compression tests was conducted under controlled temperature at 25, 40 and 60 degrees Celsius on the samples of cement admixed clay. A strength reduction ratio is introduced to compare a reduction in compressive strength with increasing temperature. The results show an optimum cement content of 10 percent at which a reduction in strength with increasing temperature is minimize. © 2010 ejge.


Uchaipichat A.,Vongchavalitkul University
Electronic Journal of Geotechnical Engineering | Year: 2010

An experimental research program of shear tests is conducted on a compacted kaolin using a conventional triaxial equipment modified for testing unsaturated soils. The modified triaxial cell is capable of independent measurement and control of pore air and pore water pressures at the top and the bottom boundaries of the specimen. The suction values varied from 0 to 300 kPa. The experimental results show the difference in relationships between shear strength and suction for drying and wetting processes. The shear strength predictions using simple failure equations for unsaturated soil in the literature are compared with the experimental results. The predictive capability of the proposed failure equations is discussed. © 2008 ejge.


Uchaipichat A.,Vongchavalitkul University
Geomechanics and Engineering | Year: 2010

An experimental program of isotropic loading tests on a compacted kaolin using a conventional triaxial equipment modified for testing unsaturated soils was perform to investigate a loading collapse curve of unsaturated soils along wetting and drying paths. The test data are presented in terms of effective stress on a range of constant suction. The suction hardening behavior was observed for both wetted and dried samples. With the use of an appropriate effective stress parameter, the unique relationship for loading collapse curve for wetting and drying processes was obtained.


Uchaipichat A.,Vongchavalitkul University | Man-Koksung E.,Vongchavalitkul University
Advanced Materials Research | Year: 2011

An experimental program of laboratory bearing tests was performed to characterize the bearing capacity of foundation on unsaturated granular soils. All tests were performed by pushing a circular rod on the surface of compacted sand specimens with different values of matric suction until failure. The test results show an increase in ultimate bearing capacity with increasing matric suction at low suction value but a decrease in that at high level of suction. The comparisons between the test results and simulations using the expressions proposed in this paper are presented and discussed. Good agreements are achieved for all testing values of suction. © (2011) Trans Tech Publications, Switzerland.


Keeratiurai P.,Vongchavalitkul University
ARPN Journal of Engineering and Applied Sciences | Year: 2015

The solid wastes were about 10 to 20 tons / cycle from the mushroom crop factories that were released into the wilderness areas, canal, public swamps or wetlands of the community. The survey to preliminary problems in the Pakthongchai district found that the quality of water in canal near the mushroom crop factories was over the industry wastewater standards. A review of anaerobic treatment of wastewater in high rate anaerobic digestion reactors was presented. Solid wastes of the mushroom crop factories were discharged to be a collection of animal breeding and disease and also have bad smell. Dust and smoke from the burning of wood used as fuel to make the mushroom. As well as problem was global climate changing from greenhouse gases emissions for energy using in the mushroom crop factories. Therefore the any problems should be studied to find solutions to control solid waste treatment, renewable energy to fuel production facility of the mushroom crop factories and the economy evaluation of the biogas plants was a renewable fuel. This study had the four conditions of hydraulic retention times were 3 days, 5 days, 7 days, and 9 days following which the all conditions were controlled system in the range of pH 7.5 ± 0.5 and 25 - 40 °C. The influence of temperature, nutrients and pH upon process performance was evaluated. A pilot-scale of the high rate anaerobic digestion reactor with vertically arranged PVC tubes as biomass carrier, treating the solid wastes of the mushroom crop factories was started-up in 31 days at ambient temperatures between 25 - 40 °C. The start-up process consisted of a long acclimatization phase followed by a low loaded growth phase at which total COD removal efficiencies of 80-90% were achieved. The results showed that the high rate anaerobic digestion reactor could be effective in removing COD are highest were 80.00%. The pH was 7.00 - 7.67 at outlet in the four hydraulic retention times. The ratio of COD: BOD was high as shown that the anaerobic biological process has the potential to eliminate the organic matter in the solid wastes. Most organic compounds containing carbon was the main component to be easily digested by microorganisms. There was a significant organic removal efficiency of the high rate anaerobic digestion tested in terms of TS, DO, COD, N, P, and K (p < 0.05). The maximum biogas production was 4.00 cm3 / day in the hydraulic retention time as 9 days. A summary of this research could to solve problems many aspects of the community. The high rate anaerobic digestion technology reduced to solid wastes and air pollution such as dust, smoke and greenhouse gases from the biogas using as fuel to the mushroom crop factories. Therefore, the factories should reduce emissions from energy consumption such as reduce electricity utilization in factories and reduce the use of firewood for heating in production. The economics evaluation of solid wastes to produce biogas showed that the internal rate of return of this project (IRR) was 17% per year, PI was 1.51, which was greater than 1, this project should be invest and the payback period was 1.33 years. © 2006-2015 Asian Research Publishing Network (ARPN).


Uchaipichat A.,Vongchavalitkul University
Key Engineering Materials | Year: 2016

This paper presents the simulation results of variation in pile capacity with temperature and suction. The end bearing, shaft friction and ultimate bearing capacities at various values temperature and matric suction were simulated. The simulation results show that the end bearing capacity decreased with increasing temperature but increased with increasing matric suction. The results also show that, with increasing temperature, the shaft friction and ultimate bearing capacities decreased at low to moderate level of suction but increased at low temperature and high level of suction. With increasing matric suction, the shaft friction and ultimate bearing capacities increased at moderate to high level of temperature but decreased at low temperature and high level of suction. © 2016 Trans Tech Publications.


Uchaipichat A.,Vongchavalitkul University
Electronic Journal of Geotechnical Engineering | Year: 2011

An elasto-plastic model for unsaturated soils including the effect of drying and wetting on a loading collapse (LC) curve is developed based on the effective stress principle. The effective stress parameter form of a function of degree of saturation is used in this paper. The elastoplastic framework satisfies the equations of total stress equilibrium, compatibility and consistency. The yield surface is affected by plastic volumetric strain and matric suction. The variation of yield surface with matric suction is obtained from the LC curve. Plastic flow is defined using a generalized associated flow rule. The simulations from the proposed model are compared with the experimental results. The predictive capabilities of the model are presented. © 2011 ejge.


Limsiri C.,Vongchavalitkul University
European Journal of Scientific Research | Year: 2011

Earthmoving equipment is a significant factor in earthwork activities. A careful selection of the equipment size and number can result in substantial savings both in time and costs. Loading and hauling the earth are among the major operations in earthwork. The size and number of the loader-hauler fleet are selected based on the production required. The selection heavily depends on skilled judgment, which may not lead to an optimal solution. The objective of this study is to introduce a technique to find the optimum, in terms of earthwork equipment for fleet selection using genetic algorithms. The optimization model for the earthmoving equipment selection is presented in this paper. A numerical example for loader-hauler fleet has been utilized to illustrate the procedure. © EuroJournals Publishing, Inc. 2011.


Uchaipichat A.,Vongchavalitkul University
European Journal of Scientific Research | Year: 2011

The theoretical work on thermal effect on cement admixed soils is performed in this paper. The thermo-elastic constitutive relations including equations for stress-temperaturestrain relations, changes in liquid mass content, and changes in entropy are developed based on the effective stress principle taking into account cementation effect. A thermoelastic framework satisfies the equations of total stress and equilibrium. The energy is transferred through solid and liquid phases. The coupling between the stress-temperaturestrain relations, changes in liquid mass content relations, and heat transfer is established through effective stress parameter and heat of compression. © EuroJournals Publishing, Inc. 2011.


Artameeyanant P.,Vongchavalitkul University
ICCAS 2010 - International Conference on Control, Automation and Systems | Year: 2010

This paper presents a method of digital image watermarking on digital audio signal that is robust against MPEG compression based on the principle of the human hearing called Psychoacoustic model. Based on the Psychoacoustic model, human hearing depends on both frequency and the power of the signal. Human ears can not separate the difference if the signal above the hearing threshold of the Psychoacoustic is varied by small amount. The Wavelet Packet Transform is chosen to transform the signal. The audio signal was decomposed using wavelet with 4 levels. A binary image is embedded into significant coefficients node (4,2) to node (4,10) selective from detail coefficient. The frequency domain and the chosen frequencies within the range of 4kHz-15kHz because it is hard for human ear to detect the difference in this range. For security, the watermark bits are randomly permuted before being embedded to the signal. Only the owner knew the key randomization which is implemented by Pseudorandom. In this experiment, 10 different audio song and 2 types of binary watermarking images of size 64x64 pixels and 32x32 pixels were tested. The results show that the normalized correlation (NC) is improved by 4.98 percent and signal-to-noise ratio (SNR) is comparable to the previous method. ©ICROS.

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