A. Wisitsoraat

Vanderbilt University, Electrical Engineering and Computer Science, Alumnus

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David Seamon

Kansas State University

Edgar Goluch

Northeastern University

Md. Shamsul Arefin

Deakin University

Amir Khamsehnezhad

TWI Ltd

Joel Taylor

Norwegian Institute for Cultural Heritage Research

Subrata Ghosh

Indira Gandhi Centre for Atomic Research

Sharma Balakrishnan

Universiti Sains Islam Malaysia (USIM)

Anupam Singha Roy

Palacky University, Olomouc

Shayne Rivers

West Dean College

Ayse Kalemtas

Bursa Technical University

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Papers by A. Wisitsoraat

Electrochemical Cholesterol Sensing System with Electropolymeriz ed

In this work, a practical cholesterol electrochemical sensing system is developed based on electr... more In this work, a practical cholesterol electrochemical sensing system is developed based on electro polymerized CNTs electrode and low cost potentiostat. Cholesterol sensor is fabricated by two-step electrochemical polymerized enzyme immobilization on a vertically aligned CNT electrode. Vertically aligned CNTs are selectively grown on a 1 mm2 window of gold coated Si02/Si substrate by thermal chemical vapor deposition (CVD) with water-assisted etching. CNTs are then simultaneously functionalized and enzyme immobilized by electrochemical polymerization of polyaniline and cholesterol enzymes. Subsequently, ineffective enzymes are removed and new enzymes are electrochemicall y recharged. Scanning electron microscopic characterization indicates polymer-enzyme nanoparticle coating on CNT surface. Cyclic voltammogram (CV) measurements in cholesterol solution show the oxidation and reduction peaks centered around 450 and -220 mY, respectively. An approximately linear relationship between th...

Pt-loaded WO 3 Thick Films for NO 2 Gas sensing

Unloaded WO3 and 0.25–1.0 wt% Pt-loaded WO3 nanoparticles were synthesized by flame spray pyrolys... more Unloaded WO3 and 0.25–1.0 wt% Pt-loaded WO3 nanoparticles were synthesized by flame spray pyrolysis (FSP). Tungsten (VI) ethoxide 5% w/v in ethanol 99.8% and platinum (II) acetylacetonate were used as W and Pt precursors respectively. The unloaded WO3 and 0.25–1.0 wt% Pt-loaded WO3 nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and High resolution transmission electron microscopy (HR-TEM). The BET surface area (SSABET) of the nanoparticles was measured by nitrogen adsorption. The thick films on alumina substrate interdigitated with gold electrodes were fabricated by spin-coating technique. The gas sensing characteristics toward NO2 (1–50 ppm) were performed at the operating temperatures ranging from 150 to 300°C.

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Ultra-responsive and selective of formic acid sensors based on flame-made SnO2 nanoparticles loaded with core-shell Ir-IrO2 nanocatalysts

Sensors and Actuators B: Chemical

Abstract 0.1–2 wt% Ir-loaded tin dioxide (SnO2) nanoparticles were prepared via flame spray pyrol... more Abstract 0.1–2 wt% Ir-loaded tin dioxide (SnO2) nanoparticles were prepared via flame spray pyrolysis and investigated for sensing of formic acid (CH2O2). The structural morphologies of the materials were investigated by various X-ray spectroscopic and electron microscopic analyses. The results revealed that very fine secondary core-shell nanoparticles containing Ir° and Ir4+ species were decorated on the surfaces of cassiterite SnO2 nanoparticles, resulting in an increase of specific surface area and a small reduction of SnO2 crystallize size. The gas-sensing performances of all fabricated sensors were evaluated towards several volatile organic acids particularly CH2O2, volatile organic compounds and hydrocarbon gases at working temperature in the range of 200–400 °C in dry and humid air. The data revealed that the 1 wt% Ir-loaded SnO2 provided the optimal sensor response of ∼1.43 × 105 to 1000 ppm CH2O2 at an optimum working temperature of 350 °C. In addition, the sensors presented moderately low humidity effect on CH2O2 response and high CH2O2 selectivity against C2H5OH, CH3OH, C3H6O, C7H8, C6H6, C8H10, HCHO, CH4, H2, C2H4O2, C3H6O2, C4H8O2, C5H10O2 and C3H6O3. The electronic and gas-sensing mechanisms could be primarily ascribed to metal-metal-semiconductor heterojunctions and catalytic effects of Ir-IrO2 via oxygen spill-over and oxygen evolution reaction mechanisms. Therefore, the loading of catalytic core-shell Ir nanoparticles on SnO2 nanostructures was a highly promising approach to achieve ultrasensitive and selective sensing of formic acid.

Industrial community odor monitoring utilizing wireless electronic nose for human health protection

The 4th 2011 Biomedical Engineering International Conference, 2012

ABSTRACT Community odor in industrial areas should be regularly monitored and controlled for huma... more ABSTRACT Community odor in industrial areas should be regularly monitored and controlled for human health protection. Wireless odor sensor is a new science-base approach highly promising for this application. In this work, wireless electronic nose has been developed for odor sensing by deploying commercial gas sensor arrays, microcontrollers and ZigBee wireless network. The system is applied for environment classification at various divisions in Bangpu industry near Swang Kaniwas rehabilitation center including tanning factory, dry leather area, bone factory, waste area and waste water treatment plant. Air data measured by multi-sensor arrays are delivered via ZigBee network to a database station where PCA as linear explorative technique analysis is used to obtain odor dispersion and air-quality classification. The ambient quality in Bangpu industrial park area has been successfully classified by the developed system. Thus, the wireless odor sensor approach has successfully demonstrated for industrial ambient quality monitoring, which is highly beneficial for human health protection.

Gas-Sensing Property Evaluation of Reactively Sputtered Chromium Oxide Thin Films

Advanced Materials Research, 2008

Metal oxide thin film materials, including SnO2, TiO2, WO3, MoO3, ZnO, have been widely studied f... more Metal oxide thin film materials, including SnO2, TiO2, WO3, MoO3, ZnO, have been widely studied for gas sensing applications. However, new gas-sensing materials with distinct and diverse characteristics for new sensing applications such as electronic nose are still being explored. Presently, gas sensing properties of other metal oxides have not yet been extensively explored. Chromium oxide is an interesting metal oxide for gas sensor because of its temperature stability and moderate electrical conductivity. Nevertheless, there have been very few studies on gas sensing behaviors of this material. In this work, chromium oxide thin films were systematically studied by reactive sputtering with varying sputtering parameter including oxygen flow rate. Structural characterization by means of scanning electron microscopy and X-ray diffraction reveals that the films have sub-micometer grain-size with Rhombohedral phase of Cr2O3. Gas-sensing performances of sputtered chromium oxide thin film ...

Ethanol sensing of La1-xSrxFeO3 (x= 0, 0.1 and 0.3) prepared by metal-organic complex decomposition

Kasetsart Journal - Natural Science

The perovskite La1-xSrxFeO3 (x= 0, 0.1 and 0.3) powders were successfully prepared by the decompo... more The perovskite La1-xSrxFeO3 (x= 0, 0.1 and 0.3) powders were successfully prepared by the decomposition of metal-organic complexes which were synthesized from the reaction of La(NO3) 3.6H2O, Fe(NO3)3.9H2O and N(CH2CH2OH)3 at 190°C in ethylene glycol solvent. The amounts of strontium nitrate used as a dopant were varied by 0, 10.0 and 30.0 mol%. The La1-xSrxFeO3 powders were obtained by calcination of metal-organic complexes at 850°C for 4 h and then were characterized by FTIR, XRD, SEM and BET. Based on semiconducting properties La1-xSrxFeO3 films prepared by spin coating were investigated for ethanol sensing. The results showed that 10% Sr(II) doped LaFeO3-based sensor, La0.9Sr 0.1FeO3, exhibited the highest sensitivity to ethanol vapour with a minimum concentration of 100 ppm at an operating temperature of 300°C.

Development of Wireless Electronic Nose for Environment Quality Classification

The ambient air quality in the live stock farm has an effect heath of animal. Therefore, we have ... more The ambient air quality in the live stock farm has an effect heath of animal. Therefore, we have developed a device for monitoring air quality of environment. In this work, wireless electronic nose has developed by deploying commercial gas sensor arrays, microcontrollers and ZigBee wireless network. They system is applied for environment classification in various laboratories including biological, chemical and

Effect of carbon doping on gas sensing properties of molybdenum oxide nanoneedles

2009 IEEE Sensors, 2009

This work presents gas sensing study of carbon doped molybdenum oxide (MoO x) nanoneedles prepare... more This work presents gas sensing study of carbon doped molybdenum oxide (MoO x) nanoneedles prepared by reactive sputtering process. The MoO x gas sensing layers have been achieved with varying carbon concentration. Structural and morphological characterization by means of SEM TEM and XRD indicate that carbon is incorporated into MoO x nanoneeles but carbon doping does not considerably affect surface morphology and crystal quality. Electrical characterizations highlight interesting behaviors for the layer tested. The MoO x film's conductance decreases by more than one order of magnitude with carbon doping. As carbon content increases, acetone and particularly ethanol responses are significantly improved by more than an order of magnitude. In contrary, hydrogen and methane response are low and relatively insensitive to carbon content. Therefore, carbon doping makes MoO x nanoneedles more selective toward volatile organic compounds (VOCs) than hydrocarbon gases. I.

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Experimental study of single-plate EWOD device for a droplet based PCR system

The 8th Electrical Engineering/ Electronics, Computer, Telecommunications and Information Technology (ECTI) Association of Thailand - Conference 2011, 2011

ABSTRACT The requirements for a polymerase chain reaction (PCR) microchip are reduction in reacti... more ABSTRACT The requirements for a polymerase chain reaction (PCR) microchip are reduction in reaction time and PCR reagent volume. In this paper, we describe the design and experimental studies of a droplet-based PCR by electrowetting on a dielectric (EWOD) chip by using the droplet basis to reduce PCR reagent volume. The droplet-based PCR system consists of a single-plate EWOD device and serpentine-shape micro heaters integrated underneath to maintain temperature for denaturation, annealing, and extension. The EWOD-based PCR system consists of 1.4 mm wide, 11 mm long and 470 11m deep microchannel and serpentine-shape microheater integrated underneath to maintain temperature at each stage. DNA was driven by moving droplet through each electrode (dimension of 2 mm width and 2 mm long) that maintains temperature at denaturation, annealing, and extension region. The single-plate EWOD based PCR device has been successfully fabricated and tested. The tested results confirm that ionized droplet can be moved with fully controlled manner by applying voltage less than 50 V. The obtained experimental datum shows that the optimized applied voltage of three microheaters for the temperature ofPCR are 1.04,0.53, and 0.91 V

Design and Simulation of Electro-fabricated MEMS Microhotplate for Gas Sensor Applications

Journal of Physics: Conference Series, 2006

In this paper, we present the simulation results of a new MEMS micro-hotplate design for gas sens... more In this paper, we present the simulation results of a new MEMS micro-hotplate design for gas sensor applications. The structure is designed to be fabricated on a glass substrate by the low cost process including physical vapor deposition, photolithography, electroplating, and photoresist-sacrificed process. The electro-thermo-mechanical behaviors of the proposed structure have been simulated by CoventorWareTM. In the simulation, the effects of thickness of the NiCr heater layer temperature, mechanical deflection, stress, and power consumption are evaluated. The 3D simulation on results show that the temperature, displacement, stress and current density are pronounced at the center of the beam as desired. At the nominal sensor temperature of ~400 C, the power consumption and Mises stress are greatly reduced from 126 to 7 mW and 1280 to 472 MPa as the thickness decreases from 5 to 0.25 m. In contrast, the compressive beam deflection is not monotonically increased as thickness increases and it is maximum at the thickness of ~0.5 m. Therefore, the simulation results indicate that the proposed design with 0.25 m-thick NiCr heater requires very low power consumption of 7 mW with low stress suitable and acceptable membrane deflection for gas sensor applications.

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Diamond field-emission triode with low gate turn-on voltage and high gain

... The low turn-on gate voltage and high gain factor are comparable to solid-state metaloxide ... more

Selectivity towards acetylene gas of flame-spray-made Nb-substituted SnO2 particulate thick films

Sensors and Actuators B: Chemical

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Effect of Er doping on flame-made SnO2 nanoparticles to ethylene oxide sensing

Sensors and Actuators B: Chemical

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P1.0.3 Pt-loaded WO3 Thick Films for NO2 Gas sensing

Proceedings IMCS 2012

Flame-spray-made PtOx-functionalized Zn2SnO4 spinel nanostructures for conductometric H2 detection

Sensors and Actuators B: Chemical

Formaldehyde sensor based on FSP-made AgOx-doped SnO2 nanoparticulate sensing films

Sensors and Actuators B: Chemical

Effect of Acetic Acid Pre-Treatment on the Growth Temperature of Graphene on Copper by Thermal Chemical Vapor Deposition

IOP Conference Series: Materials Science and Engineering

Graphene is a flat monolayer of carbon atoms arranged in a honeycomb lattice. Graphene has many o... more Graphene is a flat monolayer of carbon atoms arranged in a honeycomb lattice. Graphene has many outstanding properties such as high electron mobility, superb strength, transparency and great flexibility. These exotic properties make graphene a promising candidate for solar cell, fuel cell, battery, supercapacitor and so on. In this report, we have studied the effect of acetic acid pre-treatment on the growth temperature of graphene on copper by thermal chemical vapor deposition (CVD). In case of graphene growth without acetic acid pre-treatment, the high temperature of 1000 °C is needed for the growth of graphene by CVD. In contrast, the growth temperature can be decreased to 800 °C for graphene growth with acetic acid pre-treatment. We found that acetic acid pre-treatment can eliminate copper oxide from the sample surface resulting in the growth temperature of graphene decreases.

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Highly selective and sensitive CH4 gas sensors based on flame-spray-made Cr-doped SnO2 particulate films

Sensors and Actuators B: Chemical

Enhancement of p-type gas-sensing performances of NiO nanoparticles prepared by precipitation with RuO2 impregnation

Sensors and Actuators B: Chemical, 2016

Printed Graphene-Based Electrochemical Sensors

Mechanical and Chemical Properties, 2016

Electrochemical Cholesterol Sensing System with Electropolymeriz ed

Pt-loaded WO 3 Thick Films for NO 2 Gas sensing

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Ultra-responsive and selective of formic acid sensors based on flame-made SnO2 nanoparticles loaded with core-shell Ir-IrO2 nanocatalysts

Sensors and Actuators B: Chemical

Industrial community odor monitoring utilizing wireless electronic nose for human health protection

The 4th 2011 Biomedical Engineering International Conference, 2012

Gas-Sensing Property Evaluation of Reactively Sputtered Chromium Oxide Thin Films

Advanced Materials Research, 2008

Ethanol sensing of La1-xSrxFeO3 (x= 0, 0.1 and 0.3) prepared by metal-organic complex decomposition

Kasetsart Journal - Natural Science

Development of Wireless Electronic Nose for Environment Quality Classification

Effect of carbon doping on gas sensing properties of molybdenum oxide nanoneedles

2009 IEEE Sensors, 2009

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Experimental study of single-plate EWOD device for a droplet based PCR system

The 8th Electrical Engineering/ Electronics, Computer, Telecommunications and Information Technology (ECTI) Association of Thailand - Conference 2011, 2011