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Chatchai P.,Rajamangala University of Technology at Thanyaburi | Nosaka A.Y.,Nagaoka University of Technology | Nosaka Y.,Nagaoka University of Technology
Electrochimica Acta

The photocatalytic (PC) and photoelectrocatalytic (PEC) properties of WO3/BiVO4 photo-anode for organic dye degradation under visible light irradiation were studied. The performance of the electrodes was investigated by monitoring the % degradation of methylene blue (MB) as a dye sample with UV-vis spectroscopy. To study the charge transfer rate improvement, a Cu2O electrode was employed as a photo-cathode. In addition, Ag nanoparticles were deposited on both WO3/BiVO4 and Cu 2O electrodes to study the effect on the catalytic activity for MB degradation. SEM, XRD and XPS techniques were used to confirm the morphologies and composition of the modified electrodes. The effects of pH and the irradiation wavelengths were investigated to understand the condition of MB degradation process. The highest performance for MB degradation was attained when WO3/BiVO4 was used as a photo-anode and Cu 2O/Ag as a photo-cathode under the PEC process. © 2013 Elsevier Ltd. All rights reserved. Source

Naderi M.Y.,Northeastern University | Nintanavongsa P.,Rajamangala University of Technology at Thanyaburi | Chowdhury K.R.,Northeastern University
IEEE Transactions on Wireless Communications

Wireless charging through directed radio frequency (RF) waves is an emerging technology that can be used to replenish the battery of a sensor node, albeit at the cost of data communication in the network. This tradeoff between energy transfer and communication functions requires a fresh perspective on medium access control (MAC) protocol design for appropriately sharing the channel. Through an experimental study, we demonstrate how the placement, the chosen frequency, and number of the RF energy transmitters impact the sensor charging time. These studies are then used to design a MAC protocol called RF-MAC that optimizes energy delivery to sensor nodes, while minimizing disruption to data communication. In the course of the protocol design, we describe mechanisms for (i) setting the maximum energy charging threshold, (ii) selecting specific transmitters based on the collective impact on charging time, (iii) requesting and granting energy transfer requests, and (iv) evaluating the respective priorities of data communication and energy transfer. To the best of our knowledge, this is the first distributed MAC protocol for RF energy harvesting sensors, and through a combination of experimentation and simulation studies, we observe 300% maximum network throughput improvement over the classical modified unslotted CSMA MAC protocol. © 2014 IEEE. Source

Prasartkaew B.,Rajamangala University of Technology at Thanyaburi
Energy Procedia

Nowadays, global warming and energy crisis problems become serious issues which affect on all creatures on our earth. One of the best ways to simultaneously address or mitigate these problems is more utilizing the renewable energy sources instead of the fossil fuel. A solar-biomass hybrid cooling system is one of the technologies for the climate change and green-house-gas mitigation. The mathematical model of this system was developed and used in the theoretical prediction of its performance and system design. To assess the accuracy of the developed mathematical model, the obtained experimental data is then compared with the simulation results, with the same operating parameters and weather conditions. This paper presents the validation of the developed model. The validation results show that the simulation results are in good agreement with the experimental results from both qualitative and quantitative points of view. © 2013 The Authors. Published by Elsevier. Source

Sata V.,Khon Kaen University | Tangpagasit J.,Rajamangala University of Technology at Thanyaburi | Jaturapitakkul C.,King Mongkuts University of Technology Thonburi | Chindaprasirt P.,Khon Kaen University
Cement and Concrete Composites

In this study, the effects of W/B ratios on pozzolanic reaction of by-product biomass ashes, namely rice husk-bark ash (RHBA) and palm oil fuel ash (POFA), were determined. These biomass ashes were ground to the same fineness as that of Type I Portland cement (OPC) and partially replaced OPC at replacement levels of 10-40% by weight of binder. Water to binder (W/B) ratios of 0.50, 0.575, and 0.65 were used. The compressive strengths of mortars were compared to those of mortars made with OPC partially replaced with ground river sand of similar particle size. The results demonstrate that at the same cement replacement levels, the degrees of pozzolanic reaction of RHBA and POFA increase with W/B ratio. In addition, ground river sand with the same particle size of OPC can be used as a non-reactive material to replace OPC for determining the compressive strength due to pozzolanic reaction of biomass ash. © 2011 Elsevier Ltd. All rights reserved. Source

Lichanporn I.,Rajamangala University of Technology at Thanyaburi | Techavuthiporn C.,Christian University of Thailand
Postharvest Biology and Technology

The effect of nitric oxide and nitrous oxide on pericarp browning of longkong fruit was studied. The fruit was either dipped for 5min in 0.25mM sodium nitroprusside (SNP), a nitric oxide donor, or continually exposed to 90% nitrous oxide (N2O) vapour for 3h and was compared to the untreated fruit (control). The fruits were then stored at 13°C and RH of 90±5%. The fruit treated for 3h with nitrous oxide vapour had delayed pericarp browning with higher phenolic compounds. However, these fruit showed lower levels of phenylalanine ammonia lyase, polyphenol oxidase and peroxidase than the control fruit and those treated with 0.25mM SNP. Therefore, we conclude that nitrous oxide delays browning and reduces the activities of browning enzymes in longkong pericarp. © 2013. Source

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