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Field electron emission enhanced streamer cold plasma interaction on seed surface wettability
(2021-02-01)
Srisonphan, Siwapon
;
Kasemsuwan, Varakorn
Hybrid streamer cold plasma (HSCP) can be used in nanoscale surface modification, especially for curved biological surfaces. Here, the HSCP was applied to a rice (Oryza sativa L.) seed under different gas ambient and electric field distributions. Seed wettability enhancement (water imbibition (WI) and apparent contact angle (ACA)) is the primary method used to understand the dynamic of plasma interaction on biological surfaces. The extremely non-uniform electric field is directly responsible for plasma generation, via fringe field enhanced electron emission, which consequently impacts the ionization process. Further, this process is indirectly related to the plasma-enhanced electrochemical and physical reactions on biological nanoscale surface etching and functionalization. Despite being generated by means of different plasma mechanisms, the water imbibition time (WI<inf>time</inf>) on the top and bottom (shadow) of treated seed surfaces show similar characteristics, namely exponentially fast decay right after treatment, and a consequent linear decrease until reaching the saturation level. The stronger the corona discharge plasma, the less the difference in surface functionalization between the top and bottom surfaces. We demonstrate the model of WI<inf>time</inf> enhancement as a function of treatment time based on fringe field enhanced electron emission mediated impact ionization and reactive species (RS) generation for surface transformation.
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Electrostatic Properties and Ions Elimination Effect of Polyvinyl Chloride (PVC) Adhesive Tape Manufacturing
(2020-03-01)
Jenbanphue, Tatsanee
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Hongesombut, Komsan
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Jitkajornwanich, Kulsawasd
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Srisonphan, Siwapon
Electrostatic discharges (ESD) can release large amounts of energy to products and humans, causing product failure and pain, respectively. In this research, we elucidate the electrostatic charge generation, and discharge phenomena in real polyvinyl chloride (PVC) based electrical tape factory, which is primarily operated by the roll to roll manufacturing process. We perform the electrostatic potential measurement to identify the critical process of charge generation and to eliminate static charge at the source in order to prevent incidents caused by electrostatic discharge to operators or staff in the winding process. We also perform a numerical simulation-based finite element method (FEM) that provides modeling of an induced electric field, allowing the electrostatic discharge. The maximum potential is ~20 kV measured at 25 mm, indicating that the meter was induced by the electric field approximately ~0.8 MV/m, corresponding to surface charges density is ~ 10 μC/m<sup>2</sup>. Therefore, we introduced the ionization emitter bar in this case because it is feasible to install to the current infrastructure of the tested factory. The ionization emitter appears to reduce the electrostatic charge deposited on the PVC surface ~ 30% of the original charges. Therefore, installing a charge-dissipation technology at a proper location or combining with other methods, the electrostatic charge generation can be minimized even in roll to roll process.
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Fringe Field Assisted Electrostatic Discharge in Polypropylene Manufacturing
(2020-03-01)
Charoensorn, Panudda
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Srisonphan, Siwapon
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Kanokbannakorn, Weerawoot
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Kasemsuwan, Varakorn
Polypropylene (PP) is an electrical insulation material, and it can store electrostatic charge easily once they have friction with the metal or rubber rollers. Herein we present electrostatic issues in non-woven fabric manufacturing based on the roll to roll production processes. By using portable electrostatic-field meter measurements, we provide a low-cost and highly effective solution for discharging electrostatic charge before exposed or in contact with the operators, and we also identify where to install charge-dissipation technology to make it most useful. We employed the benefit of a highly and localized fringe field to discharge the electrostatic charge along the edge of the grounded metal rod placed at ~30 cm away. After placing the metal rod, the average of electrostatic potential of winding stock roll during spinning is decreased ~10 times, corresponding to ~0.2 μc/m<sup>3</sup> accumulated electrostatic charge on synthetic fabrics. The electric field distribution via the finite element method was illustrated corresponding to the reduction of electrostatic charge distribution in PP winding stock roll before and after inserting the grounded metal rod.
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The Grid-Based Spatial ARIMA Model: An Innovation for Short-Term Predictions of Ocean Current Patterns with Big HF Radar Data
(2020-01-01)
Pongto, Ratchanont
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Wiwattanaphon, Nopparat
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Lekpong, Peerapon
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Lawawirojwong, Siam
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Srisonphan, Siwapon
Marine natural disasters have direct impacts on countries as well as their residents living on and near the coast. Warning and monitoring system can aid in reducing the loss of lives in the event of a disaster. HF (high frequency) radar, an IoT-enabled ocean surface current monitoring system, implementation is one of the first attempts towards achieving this goal. Although HF systems can monitor sea current patterns in terms of speed and direction for each of the pixels of the coverage area, it fails to predict future values, which are essential to many applications such as oil-spill trajectory prediction (using the GNOME suite: General NOAA Operational Modeling Environment), water quality control and management, and optimized sea navigation. In this paper, we propose a model, called the grid-based spatial ARIMA (auto-regressive integrated moving average), to estimate the forecast values. As a result, the full potential of the HF systems can be utilized. The method considers not only observations of POI (point of interest), but also its neighboring pixels when predicting future values. The proposed method is implemented and compared with other existing approaches, including baseline, kNN, traditional ARIMA model, and LSTM (long short-term memory) techniques. The experimental results showed that our approach outperformed other methods in V comp prediction (with RMSEs of 6.23265) with a configuration of (2, 0, 1) as (p, d, q) and a historical dataset of 1 day and 7Â h prior. This configuration was found to be the best combination.
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Utilizing Twitter Data for Early Flood Warning in Thailand
(2018-07-02)
Jitkajornwanich, Kulsawasd
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Kongthong, Chanwit
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Khongsoontornjaroen, Nattaya
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Kaiyasuan, Jeedapa
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Lawawirojwong, Siam
Natural disasters cause significant damage to the country as well as its citizens as we have seen in the news. Drought, wild fire, earthquake and flooding are some examples of the primary natural disasters occurred in Thailand. In this research, we focus on »flooding» and use data from Twitter, where users' mobile devices are utilized as IoT input channels. The goal of this work is to analyze near real-time data (tweets) for early flood warning. Traditional methods in processing, analyzing and reporting a flooding event take quite some time. In social medias (through cellphones), on the other hand, by harvesting crowdsources, potential flooding can be predicted faster - though with the price of reliability of the retrieved tweets. In our research, several techniques are incorporated in order to maximize the accuracy of results, including, tokenization, geo-encoding and decoding, NLP via string matching (Levenshtein's algorithms), and Google APIs for visualization. Finally, the dynamic yet user-friendly map is produced with respect to the posted relevant tweets along their associated frequencies.
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Surface Modifications in Pulsed Microcoma Streamer Plasma
(2018-07-02)
Teerakawanich, Nithiphat
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Jitkajornwanich, Kulsawasd
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Piriyanont, Busara
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Srisonphan, Siwapon
Controlling liquids spreading on a surface has seen an increasing research interest over the past decade. Several methods of nanoscale surface modification via physical etching and chemical surface polymerization has been employed to engineer surfaces for various applications. The wetting properties transformation from superhydrophobic to super-hydrophilic, allowing a considerable degree of control over liquid spreading. It is essential to maximize the apparent contact angle on the surface, to achieve the high possibility of water absorption rate. Herein we substantiate the fundamental study of nanoscale surface modification via physical etching and chemical surface polymerization by using atmospheric cold plasma created by micro corona discharge. This study is simple, does not involve external chemical supplied for surface modification, and consequently can be applied to a wide range of materials.
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Microcorona Discharge-Mediated Nonthermal Atmospheric Plasma for Seed Surface Modification
(2018-07-01)
Teerakawanich, Nithiphat
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Kasemsuwan, Varakorn
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Jitkajornwanich, Kulsawasd
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Kanokbannakorn, Weerawoot
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Srisonphan, Siwapon
By exploiting the physical effect of a highly nonuniform localized electric field and electron-initiated impact ionization on space charge, we generated homogeneous nonthermal plasma under ambient atmosphere. We evaluated the physical characteristics and evolution of microcorona discharge-induced nonthermal atmospheric plasma (NAP) based on a point-to-plane electrode in open air with two distinct configurations. High-voltage pulses were employed as the primary power source of corona discharge generation to reveal the fundamental mechanism, polarity effect and feasibility of using NAP for organic surface modification. Consequently, we employed NAP to modify the surface of rice (Oryza sativa L.) seeds to improve their wettability. The surface modification of the rice seeds was investigated via water apparent contact angle (ACA) and water imbibition (WI) measurements. The ACA and WI measurements revealed not only the improvement in the wetting properties but also the mutual relationships between and limitations of ACA and WI analysis. We found that the WI time reached saturation after a certain treatment time, called the threshold treatment time. Because vacuum conditions are not required, well-established NAP technology will garner interest in many fields, ranging from the life, environmental, and biomedical sciences to solid-state electronics applications.
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Nearly Ballistic Electron Transport in an Out-of-Plane Nanoscale Defect-Void Channel
(2018-06-01)
Srisonphan, Siwapon
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Jitkajornwanich, Kulsawasd
Future nanoelectronics will require a high packing density of semiconductor devices so that electrons can be transported at speeds approaching their ultimate limit while operating at low power. Herein, we employ high-voltage pulses to create a nanoscale defect-void channel in an oxide to conduct an out-of-plane electron current from 2-D electron gas in a p-Si substrate to a metal electrode of metal-oxide-semiconductor structure. With this approach, we exploit the advantage of changes in the SiO<inf>2</inf>/Si structure after oxide breakdown and carrier transport properties to increase device performance. The electrical characteristics of the two-terminal device indicate ballistic electron transport in the nanochannel, providing potential energy-efficient and high-speed (in the picosecond regime) applications for computing systems and logic circuits with low-cost fabrication. Space-charge-limited current models offer physical insights into the formation of nanochannels containing a combination of free space and dielectric solid. Hot carrier injection in the nanochannel also provides an understanding of the defect physics via atomic luminescence and localized surface topography, as well as substantial insights via optical emission spectroscopy and atomic force microscopy into how defects rearrange themselves locally when their electronic state changes.
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Polarity effect of pulsed corona discharge plasma on seed surface modification
(2017-10-19)
Bunme, Pawita
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Khamsen, Natthaporn
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Kasemsuwan, Varakorn
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Jitkajornwanich, Kulsawasd
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Pichetjamroen, Achara
This paper presents an experimental analysis and underlying mechanism of positive and negative pulsed corona discharge induced atmospheric non-Thermal plasma. We designed a system based on point-plane configuration to produce direct corona discharge plasma (DCP) and hybrid corona discharge plasma (HCP) systems. The polarity effect of corona discharge for surface modification application on rice seeds was investigated under atmospheric dry air ambient. The reactive species under negative and positive corona discharge plasma were also studied for optimization design. The results show that only negative pulsed corona discharge is feasible for DCP system while both positive and negative pulsed corona discharge can be employed for in HCP system.
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Ocean surface current prediction based on HF radar observations using trajectory-oriented association rule mining
(2017-07-01)
Jitkajornwanich, Kulsawasd
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Vateekul, Peerapon
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Gupta, Upa
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Kormongkolkul, Teeranai
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Jirakittayakorn, Arnon
HF (high frequency) coastal radar system is used to capture the surface current behavior - in terms of velocity and direction - in the ocean near the coast. 18 HF coastal radar stations were implemented along the Gulf of Thailand in order to monitor for disasters (e.g., Tsunami) as well as relevant risks. The HF systems are also to serve other life-critical applications, such as water quality control and monitoring, chemical spill backtracking, and marine navigation. However, not all the applications can benefit from this near-real-time HF data; some applications in different domains require forecast values. The examples include search-and-rescue system and hazardous materials spill trajectory prediction. Therefore, in this paper, we propose a predictive model for future current data based on historical HF coastal radar data sets, utilizing association rule mining combined with an object dispersion concept. So, the full potential of HF radar systems can be exploited. The spatial and temporal dimensions are taken into account when designing our predictive system, which consists of two phases: ocean surface current track formulation and spatiooral association rule mining. The experiments are performed on a two-year HF radar dataset (2014-2015) using Google Cloud Platform. The resulting forecast current values: velocity and direction are then compared with testing datasets (using 10-fold cross validation) of the actual recorded values and evaluated based on percentage accuracy and RMSE, respectively.

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