The Experts below are selected from a list of 55482 Experts worldwide ranked by ideXlab platform

Dermot Diamond - One of the best experts on this subject based on the ideXlab platform.

  • Advances in wearable Chemical Sensor design for monitoring biological fluids
    Sensors and Actuators B: Chemical, 2015
    Co-Authors: Giusy Matzeu, Larisa Florea, Dermot Diamond
    Abstract:

    The state of the art and future challenges related to wearable Chemical Sensors are addressed within this review. Our attention is focused on the monitoring of biological fluids such as interstitial fluids, breath, sweat, saliva and tears, while aiming at the realization of miniaturized, non-invasive and low cost point of care systems. The development of such sensing devices is influenced by many factors and is usually addressed through the use of "smart materials" such as graphene, carbon nanotubes, poly ionic liquids, etc. These are seen as the pivotal steps towards the integration of Chemical Sensors within pervasive applications for personal health care.

  • Inkjet printed LED based pH Chemical Sensor for gas sensing.
    Analytica chimica acta, 2009
    Co-Authors: Martina O'toole, Roderick Shepherd, Gordon G Wallace, Dermot Diamond
    Abstract:

    Predictable behaviour is a critical factor when developing a Sensor for potential deployment within a wireless Sensor network (WSN). The work presented here details the fabrication and performance of an optical Chemical Sensor for gaseous acetic acid analysis, which was constructed using inkjet printed deposition of a colorimetric Chemical Sensor. The Chemical Sensor comprised a pH indicator dye (bromophenol blue), phase transfer salt tetrahexylammonium bromide and polymer ethyl cellulose dissolved in 1-butanol. A paired emitter-detector diode (PEDD) optical detector was employed to monitor responses of the colorimetric Chemical Sensor as it exhibits good sensitivity, low power consumption, is low cost, accurate and has excellent signal-to-noise ratios. The Chemical Sensor formulation was printed directly onto the surface of the emitter LED, and the resulting Chemical Sensors characterised with respect to their layer thickness, response time and recovery time. The fabrication reproducibility of inkjet printed Chemical Sensors in comparison to drop casted Chemical Sensors was investigated. Colorimetric Chemical Sensors produced by inkjet printing, exhibited an improved reproducibility for the detection of gaseous acetic acid with a relative standard deviation of 5.5% in comparison to 68.0% calculated for drop casted Sensors (n=10). The stability of the Chemical Sensor was also investigated through both intra and inter-day studies.

  • Evaluation of a low cost wireless Chemical Sensor network for environmental monitoring
    2008 IEEE Sensors, 2008
    Co-Authors: Jer Hayes, Stephen Beirne, Dermot Diamond
    Abstract:

    We present work on the development and testing of a low-cost wireless Chemical Sensor network (WCSN) for monitoring irritant/toxic gases in the environment. The WCSN used in this work takes advantage of recent advances in low power wireless communication platforms and uses colorimetric Sensors to detect the presence of certain target gases. This Sensor network adopts a star configuration and performs one way RF communications from individual Sensor nodes to the base-station. Each node in the network is composed of a multiple Sensor platform that measures light intensity, temperature and motion. The light Sensor was used as the Chemical sensing platform in such a way that the node is housed in a specially constructed sealed container that has a colorimetric Chemical sensing film coated PMMA window aperture directly above the light Sensor. The light intensity reaching the light Sensor is modulated by changes in the colour of the sensing film and such changes indicate the presence of Chemical plumes.

  • monitoring Chemical plumes in an environmental sensing chamber with a wireless Chemical Sensor network
    Sensors and Actuators B-chemical, 2007
    Co-Authors: Roderick Shepherd, Stephen Beirne, King Tong Lau, Brian Corcoran, Dermot Diamond
    Abstract:

    This paper describes the development of a wireless Chemical Sensor network (WCSN) and an environmental sensing chamber (ESC) within which this WCSN was tested. The WCSN used in this work takes advantage of recent advances in low power wireless communication platforms and novel light emitting diode (LED) based Chemical sensing techniques. Plumes of acetic acid were employed for testing and were detected by LED based colorimetric acid responsive Chemical Sensors. Wireless Sensor nodes were positioned in fixed locations within the chamber and responses to plumes of acetic acid were monitored. Preliminary test data show that Sensor response time and magnitude are related to Sensor position and plume profile, and by operating the Sensors collectively in a WCSN it was possible to track Chemical plumes in real-time as they moved through the chamber. We envisage that it will be possible to use Chemical Sensors arranged in a WCSN such as this to map and predict Chemical plume dynamics.

Sungjoon Lim - One of the best experts on this subject based on the ideXlab platform.

  • millimeter wave Chemical Sensor using substrate integrated waveguide cavity
    Sensors, 2016
    Co-Authors: Muhammad Usman Memon, Sungjoon Lim
    Abstract:

    This research proposes a substrate-integrated waveguide (SIW) cavity Sensor to detect several Chemicals using the microwave frequency range. The frequency response of the presented SIW Sensor is switched by filling a very small quantity of Chemical inside of the fluidic channel, which also causes a difference in the effective permittivity. The fluidic channel on this structure is either empty or filled with a Chemical; when it is empty the structure resonates at 17.08 GHz. There is always a different resonant frequency when any Chemical is injected into the fluidic channel. The maximum amount of Chemical after injection is held in the center of the SIW structure, which has the maximum magnitude of the electric field distribution. Thus, the objective of sensing Chemicals in this research is achieved by perturbing the electric fields of the SIW structure.

  • complementary split ring resonator loaded microfluidic ethanol Chemical Sensor
    Sensors, 2016
    Co-Authors: Ahmed Salim, Sungjoon Lim
    Abstract:

    In this paper, a complementary split-ring resonator (CSRR)-loaded patch is proposed as a microfluidic ethanol Chemical Sensor. The primary objective of this Chemical Sensor is to detect ethanol’s concentration. First, two tightly coupled concentric CSRRs loaded on a patch are realized on a Rogers RT/Duroid 5870 substrate, and then a microfluidic channel engraved on polydimethylsiloxane (PDMS) is integrated for ethanol Chemical Sensor applications. The resonant frequency of the structure before loading the microfluidic channel is 4.72 GHz. After loading the microfluidic channel, the 550 MHz shift in the resonant frequency is ascribed to the dielectric perturbation phenomenon when the ethanol concentration is varied from 0% to 100%. In order to assess the sensitivity range of our proposed Sensor, various concentrations of ethanol are tested and analyzed. Our proposed Sensor exhibits repeatability and successfully detects 10% ethanol as verified by the measurement set-up. It has created headway to a miniaturized, non-contact, low-cost, reliable, reusable, and easily fabricated design using extremely small liquid volumes.

  • microfluidic eighth mode substrate integrated waveguide antenna for compact ethanol Chemical Sensor application
    IEEE Transactions on Antennas and Propagation, 2016
    Co-Authors: Yunsik Seo, Muhammad Usman Memon, Sungjoon Lim
    Abstract:

    In this communication, a microfluidic antenna is proposed for Chemical Sensor applications. An eighth-mode substrate-integrated-waveguide (EMSIW) antenna with a microfluidic channel is introduced in order to devise a compact and nondestructive Chemical Sensor. The frequency response of the proposed antenna is controlled by changing the nanoliter liquid in the microfluidic channel, which further results in a change in the effective dielectric constant. First, the EMSIW antenna is designed, and then the microfluidic channel is designed for nondestructive Chemical Sensor applications. The S-parameters of the proposed microfluidic EMSIW antenna are simulated and measured. The resonant frequency is successfully switched from 4.2 to 4.6 GHz when the concentration of ethanol is changed from 0% to 100%. The possibility of the proposed antenna to be used as an ethanol Chemical Sensor is demonstrated from the relationship between the resonant frequency and the concentration of ethanol.

H J Guntherodt - One of the best experts on this subject based on the ideXlab platform.

  • a Chemical Sensor based on a microfabricated cantilever array with simultaneous resonance frequency and bending readout
    Sensors and Actuators B-chemical, 2001
    Co-Authors: F M Battiston, Jean Pierre Ramseyer, H P Lang, Marko Baller, Ch Gerber, James K Gimzewski, Ernst Meyer, H J Guntherodt
    Abstract:

    Abstract We present a Chemical Sensor based on a microfabricated array of eight silicon cantilevers actuated at their resonance-frequency and functionalized by polymer coatings. The operating principle relies on transduction of Chemical or physical processes into a mechanical response. After exposure to analyte vapor, analyte molecules diffuse into the cantilever coating, which begins to swell. Jointly with the mass increase, a change of interfacial stress between coating and cantilever occurs, resulting in a bending of the cantilevers. Our setup allows the simultaneous detection of cantilever oscillation and bending of eight cantilevers by time-multiplexed optical beam deflection readout. The ac component of the cantilever response is demodulated, and the cantilever resonance-frequency is tracked by a custom-built phase-locked loop. By filtering out the ac component (oscillation), the dc signal (bending) is extracted, yielding information on mass as well as surface stress changes simultaneously. Detection results of water, primary alcohols, alkanes and perfumes are presented.

  • A Chemical Sensor based on a microfabricated cantilever array with simultaneous resonance-frequency and bending readout
    Sensors and Actuators B: Chemical, 2001
    Co-Authors: F M Battiston, Jean Pierre Ramseyer, H P Lang, Marko Baller, Ch Gerber, James K Gimzewski, Ernst Meyer, H J Guntherodt
    Abstract:

    We present a Chemical Sensor based on a microfabricated array of eight silicon cantilevers actuated at their resonance-frequency and functionalized by polymer coatings. The operating principle relies on transduction of Chemical or physical processes into a mechanical response. After exposure to analyte vapor, analyte molecules diffuse into the cantilever coating, which begins to swell. Jointly with the mass increase, a change of interfacial stress between coating and cantilever occurs, resulting in a bending of the cantilevers. Our setup allows the simultaneous detection of cantilever oscillation and bending of eight cantilevers by time-multiplexed optical beam deflection readout. The ac component of the cantilever response is demodulated, and the cantilever resonance-frequency is tracked by a custom-built phase-locked loop. By filtering out the ac component (oscillation), the de signal (bending) is extracted, yielding information on mass as well as surface stress changes simultaneously. Detection results of water, primary alcohols, alkanes and perfumes are presented

H P Lang - One of the best experts on this subject based on the ideXlab platform.

  • capacitive micromachined ultrasonic transducer cmut as a Chemical Sensor for dmmp detection
    Sensors and Actuators B-chemical, 2011
    Co-Authors: Kwan Kyu Park, Mario Kupnik, Jean Pierre Ramseyer, H P Lang, Martin Hegner, Christoph Gerber, Omer Oralkan, B T Khuriyakub
    Abstract:

    a b s t r a c t We present a Chemical Sensor based on a capacitive micromachined ultrasonic transducer (CMUT) con- figured as a resonant mass Sensor with a Chemically selective polymer coating. The sensing unit of the CMUT consists of 100s to 1000s of resonators connected in parallel and acts as a single resonator. The high resonant frequency (18.2 MHz) and the small mass (296 pg) enable the CMUT to have a good mass sensitivity of 130 zg/Hz/m2. We functionalized the CMUT with polyisobutylene (PIB) as the sorbent film, which targets dimethyl methylphosphonate (DMMP), a simulant for nerve agent, sarin. An oscilla- tor circuit was populated to trace the resonant frequency of the CMUT with a fast response time and low noise. We characterized the noise performance of the Sensor system and identified the optimal gate time of the read-out frequency counter. Based on the noise measurement, the calculated limit of detection (LOD) of mass loading is 0.192 ag/m 2 (3-� confidence level). Chemical experiments were performed on the CMUT Sensor with several analytes including DMMP, water, and ethanol. The limit of detection of the CMUT Chemical Sensor to DMMP vapor was measured as 56 ppb (3-� confidence level).

  • a Chemical Sensor based on a microfabricated cantilever array with simultaneous resonance frequency and bending readout
    Sensors and Actuators B-chemical, 2001
    Co-Authors: F M Battiston, Jean Pierre Ramseyer, H P Lang, Marko Baller, Ch Gerber, James K Gimzewski, Ernst Meyer, H J Guntherodt
    Abstract:

    Abstract We present a Chemical Sensor based on a microfabricated array of eight silicon cantilevers actuated at their resonance-frequency and functionalized by polymer coatings. The operating principle relies on transduction of Chemical or physical processes into a mechanical response. After exposure to analyte vapor, analyte molecules diffuse into the cantilever coating, which begins to swell. Jointly with the mass increase, a change of interfacial stress between coating and cantilever occurs, resulting in a bending of the cantilevers. Our setup allows the simultaneous detection of cantilever oscillation and bending of eight cantilevers by time-multiplexed optical beam deflection readout. The ac component of the cantilever response is demodulated, and the cantilever resonance-frequency is tracked by a custom-built phase-locked loop. By filtering out the ac component (oscillation), the dc signal (bending) is extracted, yielding information on mass as well as surface stress changes simultaneously. Detection results of water, primary alcohols, alkanes and perfumes are presented.

  • A Chemical Sensor based on a microfabricated cantilever array with simultaneous resonance-frequency and bending readout
    Sensors and Actuators B: Chemical, 2001
    Co-Authors: F M Battiston, Jean Pierre Ramseyer, H P Lang, Marko Baller, Ch Gerber, James K Gimzewski, Ernst Meyer, H J Guntherodt
    Abstract:

    We present a Chemical Sensor based on a microfabricated array of eight silicon cantilevers actuated at their resonance-frequency and functionalized by polymer coatings. The operating principle relies on transduction of Chemical or physical processes into a mechanical response. After exposure to analyte vapor, analyte molecules diffuse into the cantilever coating, which begins to swell. Jointly with the mass increase, a change of interfacial stress between coating and cantilever occurs, resulting in a bending of the cantilevers. Our setup allows the simultaneous detection of cantilever oscillation and bending of eight cantilevers by time-multiplexed optical beam deflection readout. The ac component of the cantilever response is demodulated, and the cantilever resonance-frequency is tracked by a custom-built phase-locked loop. By filtering out the ac component (oscillation), the de signal (bending) is extracted, yielding information on mass as well as surface stress changes simultaneously. Detection results of water, primary alcohols, alkanes and perfumes are presented

Roderick Shepherd - One of the best experts on this subject based on the ideXlab platform.

  • Inkjet printed LED based pH Chemical Sensor for gas sensing.
    Analytica chimica acta, 2009
    Co-Authors: Martina O'toole, Roderick Shepherd, Gordon G Wallace, Dermot Diamond
    Abstract:

    Predictable behaviour is a critical factor when developing a Sensor for potential deployment within a wireless Sensor network (WSN). The work presented here details the fabrication and performance of an optical Chemical Sensor for gaseous acetic acid analysis, which was constructed using inkjet printed deposition of a colorimetric Chemical Sensor. The Chemical Sensor comprised a pH indicator dye (bromophenol blue), phase transfer salt tetrahexylammonium bromide and polymer ethyl cellulose dissolved in 1-butanol. A paired emitter-detector diode (PEDD) optical detector was employed to monitor responses of the colorimetric Chemical Sensor as it exhibits good sensitivity, low power consumption, is low cost, accurate and has excellent signal-to-noise ratios. The Chemical Sensor formulation was printed directly onto the surface of the emitter LED, and the resulting Chemical Sensors characterised with respect to their layer thickness, response time and recovery time. The fabrication reproducibility of inkjet printed Chemical Sensors in comparison to drop casted Chemical Sensors was investigated. Colorimetric Chemical Sensors produced by inkjet printing, exhibited an improved reproducibility for the detection of gaseous acetic acid with a relative standard deviation of 5.5% in comparison to 68.0% calculated for drop casted Sensors (n=10). The stability of the Chemical Sensor was also investigated through both intra and inter-day studies.

  • monitoring Chemical plumes in an environmental sensing chamber with a wireless Chemical Sensor network
    Sensors and Actuators B-chemical, 2007
    Co-Authors: Roderick Shepherd, Stephen Beirne, King Tong Lau, Brian Corcoran, Dermot Diamond
    Abstract:

    This paper describes the development of a wireless Chemical Sensor network (WCSN) and an environmental sensing chamber (ESC) within which this WCSN was tested. The WCSN used in this work takes advantage of recent advances in low power wireless communication platforms and novel light emitting diode (LED) based Chemical sensing techniques. Plumes of acetic acid were employed for testing and were detected by LED based colorimetric acid responsive Chemical Sensors. Wireless Sensor nodes were positioned in fixed locations within the chamber and responses to plumes of acetic acid were monitored. Preliminary test data show that Sensor response time and magnitude are related to Sensor position and plume profile, and by operating the Sensors collectively in a WCSN it was possible to track Chemical plumes in real-time as they moved through the chamber. We envisage that it will be possible to use Chemical Sensors arranged in a WCSN such as this to map and predict Chemical plume dynamics.