KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Search Results

Now showing 1 - 10 of 48

Some of the metrics are blocked by your
consent settings
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.
Some of the metrics are blocked by your
consent settings
Fringe Field Assisted Electrostatic Discharge in Polypropylene Manufacturing
(2020-03-01)
Charoensorn, Panudda
;
Srisonphan, Siwapon
;
Kanokbannakorn, Weerawoot
;
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.
Some of the metrics are blocked by your
consent settings
ISFET's Interface Circuit for Biomedical Applications Using Delta-Sigma Modulation
(2019-01-10)
Bumrungyat, Puvanat
;
Kasemsuwan, Varakorn
This paper presents a new ISFET's interface circuit for biomedical applications using delta-sigma modulation. The proposed design operates ISFET in the linear region so that an output current is linearly dependent on pH over a wide range (pH 2 to pH 14). Conversion to a digital output domain is done using a sigma-delta converter making the interface circuit very robust and reliable for most sensor applications. The proposed circuit is designed in a 0.18 μm technology. The supply voltage is 1.8 V and the total current drawn is 56 μA. The simulation results show that the proposed circuit can sense a pH with an error within the range of -0.2% to 0.3% for pH ranging from 2 to 14.
Some of the metrics are blocked by your
consent settings
Microcorona Discharge-Mediated Nonthermal Atmospheric Plasma for Seed Surface Modification
(2018-07-01)
Teerakawanich, Nithiphat
;
Kasemsuwan, Varakorn
;
Jitkajornwanich, Kulsawasd
;
Kanokbannakorn, Weerawoot
;
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.
Some of the metrics are blocked by your
consent settings
Polarity effect of pulsed corona discharge plasma on seed surface modification
(2017-10-19)
Bunme, Pawita
;
Khamsen, Natthaporn
;
Kasemsuwan, Varakorn
;
Jitkajornwanich, Kulsawasd
;
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.
Some of the metrics are blocked by your
consent settings
Low-voltage current-mode preamplifier based Latch comparator
(2016-09-06)
Jankatkit, Thongchai
;
Kasemsuwan, Varakorn
This paper presents a low-voltage latch current comparator. The circuit was designed on the basis of current mirror, preamplifier and latch circuits and also various circuit techniques; quasi-floating gate to reduce the input impedance, bulk driven technique for the circuit to be operable under low supply voltage and positive feedback to increase the gain and the overall speed. From the simulation results, which were presented with 0.18 um CMOS technology, the circuit can operate well at the supply voltage of 0.5 volt and the resulting propagation delay time were 2.2 nS and 1.4 nS when the input current differences are 1 uA and 10 uA, respectively. The total power dissipation was 79 uW.
Some of the metrics are blocked by your
consent settings
Low-voltage bulk-driven QFG-regulated self-cascode super MOS transistor
(2016-09-06)
Thongleam, Thawatchai
;
Suadet, Apirak
;
Kasemsuwan, Varakorn
A bulk-driven super MOS transistor (BD-SMT) for low voltage operation is presented. The proposed transistor achieves a high effective transconductance (G<inf>m(eff)</inf>), high effective drain impedance (R<inf>D(eff)</inf>) and low effective source impedance (R<inf>S(eff)</inf>). BD-SMT is designed based on regulated self-cascode and negative feedback techniques. The transistor been designed using a 0.18 μm CMOS technology and operated from a 0.4 V supply with a static power consumption of 12 μW. The simulation results showed higher G<inf>m(eff)</inf>, larger R<inf>D(eff)</inf> and smaller R<inf>S(eff)</inf> as compared to those of simple bulk-driven MOS transistor.
Some of the metrics are blocked by your
consent settings
Feedforward bulk-driven class AB fully-differential second-generation current conveyor (FDCCII)
(2014-01-01)
Thongleam, Thawatchai
;
Kasemsuwan, Varakorn
In this paper, a feedforward bulk-driven class AB fully-differential second-generation current conveyer (FDCCII) is presented. Bulk-driven differential pair is employed for the input stage allowing the FDCCII to operate with rail-to-rail operation. Feedfoward technique is also incorporated into input stage to increase the DC gain and minimize the common mode gain. The circuit performance is verified using HSPICE in 0.18 μm CMOS technology. The simulation results show rail-to-rail input and output swings. The DC voltage transfer characteristic between ports Y and X and DC current transfer characteristic between ports X and Z shows good linearity. The bandwidths show 25.7 MHz (V<inf>X</inf>/V<inf>Y</inf>), 30 MHz (I<inf>Z</inf>/I<inf>X</inf>), respectively. The power dissipation is 267.5 μW. © (2014) Trans Tech Publications, Switzerland.
Some of the metrics are blocked by your
consent settings
A compact class-AB bulk-driven quasi-floating gate current mirror for low voltage applications
(2013-12-31)
Suadet, Apirak
;
Kasemsuwan, Varakorn
A compact class-AB bulk-driven quasi-floating gate current mirror is proposed. The circuit is based on an active class-A current mirror using bulk-driven quasi-floating gate (BD-QFG) MOS transistors and low voltage bulk-input pseudo-differential amplifier. The circuit can operate from a supply voltage as low as V<inf>T</inf>+V<inf>DSAT</inf>. The performance of the circuit is verified by SPECTRE, using a standard 0.18 μm CMOS process with a 0.5 V supply voltage. The circuit demonstrates low input impedance (934 Ω) and relatively high output impedance (1.13 MΩ). The circuit can drive the output current 8 times larger than the quiescent current. The power dissipation under quiescent condition is 8.2 μW. © 2013 IEEE.
Some of the metrics are blocked by your
consent settings
A CMOS inverter-based class-AB pseudo-differential amplifier with current-mode common-mode feedback (CMFB)
(2013-02-01)
Suadet, Apirak
;
Kasemsuwan, Varakorn
This paper presents a CMOS inverter-based class-AB pseudo-differential amplifier comprising currentmode common-mode feedback (CMFB). The circuit employs two CMOS inverters and the complementary CMFB consisting of current-mode common-mode (CM) detector and transimpedance amplifier. The circuit has been designed using 0.18 lm CMOS technology and operates at 1 V supply. The simulation results demonstrate rail-to-rail operation with low CM gain (-15 dB). The power dissipation of the circuit is 102.5 lW. © Springer Science+Business Media, LLC 2012.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results