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Horpibulsuk S.,Suranaree University of Technology | Yangsukkaseam N.,Rajamangala University of Technology at Suvarnabhumi | Chinkulkijniwat A.,Suranaree University of Technology | Du Y.J.,Nanjing Southeast University
Applied Clay Science | Year: 2011

The physical and engineering properties of remolded clays are intrinsic and can be used as a frame of reference for the behavior of clay. Compressibility and permeability of remolded Bangkok clay at different ion concentrations and valences were compared with kaolin and bentonite as representatives of non- and high swelling clays. Bangkok clay, a low-swelling clay, exhibited physical and engineering properties similar to those of kaolin. The texture of coagulated Bangkok clay became a more flocculated structure with increasing ion concentration and valence, resulting in higher water holding capacity and liquid limit. Even though the physical properties of all tested clays varied significantly with pore water chemistry, the (PI, LL) points lied above the A-line in the plasticity chart (where PI is the plasticity index and LL is the liquid limit) and could be represented by a unique relationship. The change of the intrinsic compressibility and permeability with the concentration and valence of the ions was interpreted by a generalized stress state e/eL. The lower e/eL value was associated with higher shear strength (resistance to vertical consolidation pressure in K0-consolidation) and lower permeability. As the ion concentration and valence were increased for both kaolin and Bangkok clay, the resistance to consolidation pressure increased and permeability decreased for the same void ratio due to the decrease in e/eL. The liquid limit for bentonite decreased with increasing ion concentration and valence due to the compression of the diffuse double layer. Hence, for the same void ratio, the resistance to consolidation pressure decreased and permeability increased due to the increase of e/eL. Finally, relationships of the modified void index, I'v and consolidation pressure, σ'v, and generalized stress state e/eL and permeability k were proposed. These relationships are useful and practical tools for assessing the intrinsic compressibility and permeability of non- to high-swelling clays in terms of liquid limit, which is easily obtained from conventional laboratory tests. © 2011 Elsevier B.V.

Chaithongsuk S.,Rajamangala University of Technology at Suvarnabhumi | Nahid-Mobarakeh B.,University of Lorraine | Caron J.-P.,University of Lorraine | Takorabet N.,University of Lorraine | Meibody-Tabar F.,University of Lorraine
IEEE Transactions on Industrial Electronics | Year: 2012

Two motors are studied and optimized for transportation applications. The objective is to design motors whose external model is well suited for conventional vector control. Hence, in the design procedure, the emphasis is on the backelectromotive force (EMF) waveforms and external parameters. The first topology is a surface-mounted (nonsalient pole) motor with segmented magnets reducing significantly selected harmonics. The second is an inset magnet type (salient pole) motor with surface poles particularly shaped to reduce the harmonic content of the air gap flux density. For both motors, the principle of pulse width modulation is used for the harmonic reduction in the design process. The interest of these motors lies in the sinusoidal waveform of their back EMF allowing a simple vector control even at field-weakening region for high speeds. © 2011 IEEE.

Tripetch K.,Rajamangala University of Technology at Suvarnabhumi
IEEE Vehicular Technology Conference | Year: 2014

This paper proposes a study of input impedance of 2 types of CMOS active inductors. It derives 2 input impedance formulas. The first formula is the input impedance of the grounded active inductor. The second formula is the input impedance of the floating active inductor. After that, these formulas can be used to simulate magnitude and phase response of input impedance as a function of current consumption with MATLAB. Common mode rejection ratio (CMRR) of the fully differential bandpass amplifier is derived based on superposition principle. CMRR as a function of input frequency is plotted as a function of current consumption. © 2014 IEEE.

Udomhunsakul S.,Rajamangala University of Technology at Suvarnabhumi
International Journal of Circuits, Systems and Signal Processing | Year: 2013

Noise reduction is one of the most essential processes for image processing. The goal of the noise reduction is how to remove noise while keeping the important image features as much as possible. In this paper, a novel method to remove additive noise from digital image, based on the combination of Gaussian filter and the singular value decomposition, is proposed. Firstly, Gaussian filter is used to classify noisy image into two parts, which are its blur and noisy edge images. Next, the noise on noisy edge image, obtained from the difference between the original noisy image and its blur image, is reduced by using an adaptive block-based singular value decomposition filtering (BSVD). Finally, the reconstruction images are obtained from combining between noisy edge image, filtered by an adaptive BSVD filtering, and its original blur image. From the experiments, the objective and subjective measurements prove that the proposed approach compared with traditionally methods can suppress noise, preserve the significant image features as well as effectively smooth in the homogeneous area. Therefore, the proposed method leads to a practical method to be used for noise reduction.

Tripetch K.,Rajamangala University of Technology at Suvarnabhumi
SPEEDAM 2012 - 21st International Symposium on Power Electronics, Electrical Drives, Automation and Motion | Year: 2012

This paper introduces techniques which can be used to step down input voltage. It is different from traditional idea which use duty cycle concept. By using frequency domain concept low pass active filter can be used to step down input voltage. While high pass active filter can be used to step up output voltage. High precision supply voltage at 1mV step can be generated by the proposed techniques without the series resistor and switches more than 1000 pieces if the cut off frequency of the filter is accurate enough. If the input voltage is not as high as 15 volt, op-amp model LF353 can be used to implement step down converter. © 2012 IEEE.

Tripetch K.,Rajamangala University of Technology at Suvarnabhumi
Lecture Notes in Engineering and Computer Science | Year: 2013

Tuning Range of Oscillator is one of the important specification which is used in phase locked loop. The more wider tuning range, the better the phase lock loop. This paper proposed regulated cascode cross coupled based CMOS oscillator. The analysis and simulation results of tuning range of this type of oscillator are compared with conventional Colpitts based CMOS oscillator as a function of bias current consumption.

Worrakitpoonpon T.,Rajamangala University of Technology at Suvarnabhumi
Monthly Notices of the Royal Astronomical Society | Year: 2014

We study, using N-body simulation, the shape evolution in gravitational collapse of cold uniform spherical system. The central interest is on howthe deviation from spherical symmetry depends on particle number N. By revisit of the spherical collapse model, we hypothesize that the departure from spherical symmetry is regulated by the finite-N density fluctuation. Following this assumption, the estimate of the flattening of relaxed structures is derived to be N-1/3. In numerical part, we find that the virialized states can be characterized by the core-halo structures and the flattenings of the cores fit reasonably well with the prediction. Moreover, the results from large N systems suggest the divergence of relaxation time to the final shapes with N.We also find that the intrinsic shapes of the cores are considerably diverse as they vary from nearly spherical, prolate, oblate or completely triaxial in each realization. When N increases, this variation is suppressed as the final shapes do not differ much from initial symmetry. In addition, we observe the stable rotation of the virialized states. Further investigation reveals that the origin of this rotation is related in some way to the initial density fluctuation. © 2014 The Authors.

Archevapanich T.,Rajamangala University of Technology at Suvarnabhumi
ICCAS 2010 - International Conference on Control, Automation and Systems | Year: 2010

The conventional CPW fed rectangular slot antenna create dual narrow band. The single wideband antenna can obtain by using tuning stub. This paper describes a modified tuning stub of CPW fed rectangular slot antenna to achieve single wide bandwidth. The prototype of tuning stub is designed with several parameters, the significant modified by cutting on vertical narrow strips of tuning stub to achieve four different geometries. The comparison on the simulated return loss shows the bandwidth, the widest bandwidth with good matching is choosing. The wide slot antenna fed by coplanar waveguide (CPW) with tuning stub is designed on low cost substrate FR4 to achieve single wide bandwidth coverage standard of WLAN IEEE 802.11b/g/j/a/n (2.4 -2.4835 GHz, 4.9-5.1 GHz, 5.15-5.35 GHz, 5.7-5.9 GHz) and WiMAX (3.5 GHz) from frequency range 2.29-6.94 GHz. ©ICROS.

Unahalekhaka P.,Rajamangala University of Technology at Suvarnabhumi
Energy Procedia | Year: 2014

This paper describes simplified modeling of metal oxide surge arrester (MOSA) to operate analysis. This model is a new model proposed (P-K Model) to verify the accuracy in order to compare with IEEE and Pinceti Model. The simulations are performed with the Alternative Transients Program version of Electromagnetic Transient Program (ATP-EMTP). In the present paper, the MOSA models were verified for several medium voltages which consist of 18 kV and 21 kV, which 18 kV arrester was used in 22 kV system of Provincical Electricity Authority (PEA) and 21 kV arrester was used in 24 kV system of Metropolitan Electricity Authority (MEA) in Thailand. The P-K model was evaluate from different manufacturing, it is based on the General Electric (GE), Siemens and Ohio Brass as well as IEEE and Pinceti Model. The tests are performed by applying a fast front current surge with front time of up to 0.5μs and the standard impulse current surge (8/20μs). The results were compared between three models in order to calculate the error operation of the MOSA in the ATP-EMTP Program. The relative error of arrester models show that the P-K model can be used to simulate and calculate in ATP-EMTP program as well as IEEE and Pinceti model. In the case of fast front current surge, the P-K model has a maximum error of 5.39% (Ohio Brass, 10 kA, 21 kV) and has a minimum error of 0.24% (GE, 10 kA, 18 kV). Also, the standard impulse current surge, P-K model has a maximum error of 2% (Ohio Brass, 10 kA, 18 kV) and has a minimum error of 0.32% (Siemens, 10 kA, 21 kV) in the voltage response. © 2014 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.

Phumcharoen J.,Rajamangala University of Technology at Suvarnabhumi
2016 6th International Workshop on Computer Science and Engineering, WCSE 2016 | Year: 2016

Thailand Quality Framework (TQF) is mainly the framework that is used to regulate all the higher educations in Thailand. The framework provides basic requirements for all curriculums in higher education in Thailand. Therefore, all the curriculums taught in Thailand must comply with the framework. When the initial version of the framework was introduced to the universities, the framework was completed to deploy to each curriculum, as there are many documents to involve in the process. Therefore, in order to improve the quality assurance of the framework to the faculties, this paper proposed the development of the Management TQF database system (M-TQF). In this work, all of the satisfaction of the actors that interacts with the framework including the lecturer, staff of the Faculty of Science and Technology in the Rajamangala University of Technology Suvarnabhumi were collected. Then the sample was purposively selected from Computer Science and Information Technology programs and analyzed. Finally, based on the information analyzed, the database of the TQF in the Faculty of Science and Technology was proposed to improve the deployment of the new curriculum in the field of Information Technology.

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