scholarly journals Review of the gas breakdown physics and nanomaterial-based ionization gas sensors and their applications

2021 ◽  
Author(s):  
June Young Kim ◽  
Igor D Kaganovich ◽  
Lee Hyo-Chang
Keyword(s):  
Gas Sensors ◽  
Technological Development ◽  
Secondary Electron Emission ◽  
Sensor Technology ◽  
Future Directions ◽  
Breakdown Mechanism ◽  
Working Principle ◽  
Living Organisms ◽  
Gas Breakdown ◽  
Townsend Discharge

Abstract Ionization gas sensors are a ubiquitous tool that can monitor desired gases or detect abnormalities in real time to protect the environment of living organisms or to maintain clean and/or safe environment in industries. The sensors’ working principle is based on the fingerprinting of the breakdown voltage of one or more target gases using nanostructured materials. Fundamentally, nanomaterial-based ionization-gas sensors operate within a large framework of gas breakdown physics; signifying that an overall understanding of the gas breakdown mechanism is a crucial factor in the technological development of ionization gas sensors. Moreover, many studies have revealed that physical properties of nanomaterials play decisive roles in the gas breakdown physics and the performance of plasma-based gas sensors. Based on this insight, this review provides a comprehensive description of the foundation of both the gas breakdown physics and the nanomaterial-based ionization-gas-sensor technology, as well as introduces research trends on nanomaterial-based ionization gas sensors. The gas breakdown is reviewed, including the classical Townsend discharge theory and modified Paschen curves; and nanomaterial-based-electrodes proposed to improve the performance of ionization gas sensors are introduced. The secondary electron emission at the electrode surface is the key plasma–surface process that affects the performance of ionization gas sensors. Finally, we present our perspectives on possible future directions.

scholarly journals Multiple Stressor Effects of Radon and Phthalates in Children: Background Information and Future Research

2020 ◽  
Vol 17 (8) ◽  
pp. 2898
Author(s):  
W. S. Kwan ◽  
D. Nikezic ◽  
Vellaisamy A. L. Roy ◽  
K. N. Yu
Keyword(s):  
Pediatric Population ◽  
Research Work ◽  
Consumer Products ◽  
Background Information ◽  
Future Research ◽  
Future Directions ◽  
Lung Cancers ◽  
Multiple Stressor ◽  
Biological Studies ◽  
Living Organisms

The present paper reviews available background information for studying multiple stressor effects of radon (222Rn) and phthalates in children and provides insights on future directions. In realistic situations, living organisms are collectively subjected to many environmental stressors, with the resultant effects being referred to as multiple stressor effects. Radon is a naturally occurring radioactive gas that can lead to lung cancers. On the other hand, phthalates are semi-volatile organic compounds widely applied as plasticizers to provide flexibility to plastic in consumer products. Links of phthalates to various health effects have been reported, including allergy and asthma. In the present review, the focus on indoor contaminants was due to their higher concentrations and to the higher indoor occupancy factor, while the focus on the pediatric population was due to their inherent sensitivity and their spending more time close to the floor. Two main future directions in studying multiple stressor effects of radon and phthalates in children were proposed. The first one was on computational modeling and micro-dosimetric studies, and the second one was on biological studies. In particular, dose-response relationship and effect-specific models for combined exposures to radon and phthalates would be necessary. The ideas and methodology behind such proposed research work are also applicable to studies on multiple stressor effects of collective exposures to other significant airborne contaminants, and to population groups other than children.

scholarly journals Advanced Micro- and Nano-Gas Sensor Technology: A Review

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1285 ◽  
Author(s):  
Haleh Nazemi ◽  
Aashish Joseph ◽  
Jaewoo Park ◽  
Arezoo Emadi
Keyword(s):  
Gas Sensor ◽  
Gas Sensors ◽  
High Performance ◽  
Sensor Arrays ◽  
Sensor Technology ◽  
Sensor Design ◽  
Fabrication Technology ◽  
Nano Fabrication ◽  
Wide Range ◽  
Gas Sensor Arrays

Micro- and nano-sensors lie at the heart of critical innovation in fields ranging from medical to environmental sciences. In recent years, there has been a significant improvement in sensor design along with the advances in micro- and nano-fabrication technology and the use of newly designed materials, leading to the development of high-performance gas sensors. Advanced micro- and nano-fabrication technology enables miniaturization of these sensors into micro-sized gas sensor arrays while maintaining the sensing performance. These capabilities facilitate the development of miniaturized integrated gas sensor arrays that enhance both sensor sensitivity and selectivity towards various analytes. In the past, several micro- and nano-gas sensors have been proposed and investigated where each type of sensor exhibits various advantages and limitations in sensing resolution, operating power, response, and recovery time. This paper presents an overview of the recent progress made in a wide range of gas-sensing technology. The sensing functionalizing materials, the advanced micro-machining fabrication methods, as well as their constraints on the sensor design, are discussed. The sensors’ working mechanisms and their structures and configurations are reviewed. Finally, the future development outlook and the potential applications made feasible by each category of the sensors are discussed.

scholarly journals Technological mediation in the future of experiential tourism

2019 ◽  
Vol 5 (2) ◽  
pp. 120-126 ◽  
Author(s):  
Ellis Urquhart
Keyword(s):  
Technological Development ◽  
Tourism Industry ◽  
Future Directions ◽  
Technological Mediation ◽  
Content Type ◽  
Academic Literature ◽  
Considerable Research ◽  
Theoretical Perspectives ◽  
The Future ◽  
Insight Into

Purpose The purpose of this paper is to consider the role that technology may play in the future of experiential tourism. This viewpoint paper begins to question future developments in technological mediation and how these may challenge the author’ view of experiences and their construction in a period of immense and rapid technological development. Design/methodology/approach This is a short viewpoint paper driven by theoretical perspectives in the existing academic literature and the author’s personal stance on the future of experiential tourism. Findings This paper suggests that while there is considerable research into the role and application of technology within tourism, there is a lack of future-orientated debate. The views expressed within the paper argue that three potential directions exist for the future of technological mediation in experiential tourism: mass acceptance and customisation; experiential convergence or “rewinding the clock”, each with significant implications for the management of technological mediation in experiential tourism. Originality/value The paper provides an initial insight into future directions of the tourism industry in a period of immense technological development. Based on existing theoretical perspectives, these viewpoints indicate three potential routes for the industry and act as a catalyst for further dialogue within tourism scholarship.

scholarly journals Involvement of Various Enzymes in the Physiology and Pathogenesis of Streptococcus suis

2020 ◽  
Vol 7 (4) ◽  
pp. 143
Author(s):  
Chengkun Zheng ◽  
Man Wei ◽  
Mengdie Jia ◽  
ManMan Cao
Keyword(s):  
Streptococcus Suis ◽  
Infection Process ◽  
Swine Industry ◽  
Serine Threonine Kinase ◽  
Future Directions ◽  
Threonine Kinase ◽  
Severe Infections ◽  
Living Organisms ◽  
Almost All

Streptococcus suis causes severe infections in both swine and humans, making it a serious threat to the swine industry and public health. Insight into the physiology and pathogenesis of S. suis undoubtedly contributes to the control of its infection. During the infection process, a wide variety of virulence factors enable S. suis to colonize, invade, and spread in the host, thus causing localized infections and/or systemic diseases. Enzymes catalyze almost all aspects of metabolism in living organisms. Numerous enzymes have been characterized in extensive detail in S. suis, and have shown to be involved in the pathogenesis and/or physiology of this pathogen. In this review, we describe the progress in the study of some representative enzymes in S. suis, such as ATPases, immunoglobulin-degrading enzymes, and eukaryote-like serine/threonine kinase and phosphatase, and we highlight the important role of various enzymes in the physiology and pathogenesis of this pathogen. The controversies about the current understanding of certain enzymes are also discussed here. Additionally, we provide suggestions about future directions in the study of enzymes in S. suis.

scholarly journals Enzymes of yeast polyphosphate metabolism: structure, enzymology and biological roles

2016 ◽  
Vol 44 (1) ◽  
pp. 234-239 ◽  
Author(s):  
Rūta Gerasimaitė ◽  
Andreas Mayer
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Blood Coagulation ◽  
Bone Mineralization ◽  
Inorganic Polyphosphate ◽  
Yeast Saccharomyces Cerevisiae ◽  
Future Directions ◽  
Short Overview ◽  
Metabolism Enzymes ◽  
Living Organisms ◽  
Polyphosphate Metabolism

Inorganic polyphosphate (polyP) is found in all living organisms. The known polyP functions in eukaryotes range from osmoregulation and virulence in parasitic protozoa to modulating blood coagulation, inflammation, bone mineralization and cellular signalling in mammals. However mechanisms of regulation and even the identity of involved proteins in many cases remain obscure. Most of the insights obtained so far stem from studies in the yeast Saccharomyces cerevisiae. Here, we provide a short overview of the properties and functions of known yeast polyP metabolism enzymes and discuss future directions for polyP research.

Organic field-effect transistor-based gas sensors

2015 ◽  
Vol 44 (8) ◽  
pp. 2087-2107 ◽  
Author(s):  
Congcong Zhang ◽  
Penglei Chen ◽  
Wenping Hu
Keyword(s):  
Gas Sensors ◽  
Field Effect ◽  
High Performance ◽  
Recent Progress ◽  
Field Effect Transistor ◽  
Organic Field Effect Transistor ◽  
Working Principle ◽  
Effect Transistor ◽  
Review Reports

This tutorial review reports the recent progress on OFET gas sensors, including their working principle, and protocols for high-performance sensing.

scholarly journals Optics-less smart sensors and a possible mechanism of cutaneous vision in nature

Open Physics ◽  
2010 ◽  
Vol 8 (3) ◽  
Author(s):  
Leonid Yaroslavsky ◽  
Chad Goerzen ◽  
Stanislav Umansky ◽  
H. Caulfield
Keyword(s):  
Parameter Estimation ◽  
Numerical Simulations ◽  
Statistical Parameter ◽  
Radiation Detectors ◽  
Estimation Theory ◽  
Curved Surface ◽  
Smart Sensors ◽  
Working Principle ◽  
Living Organisms ◽  
Shed Light

AbstractAlthough optics-less cutaneous (“skin”) vision is not uncommon among living organisms, its mechanisms and capabilities have not been thoroughly investigated. This paper demonstrates, using methods from statistical parameter estimation theory and numerical simulations, that arrays of bare radiation detectors arranged on a planar or curved surface have the ability to perform imaging tasks without any optics at all. The working principle of this type of optics-less sensors and the model developed here for determining their performance may be used to shed light on possible mechanisms, capabilities and evolution of cutaneous vision in nature.

scholarly journals DC GAS BREAKDOWN AND TOWNSEND DISCHARGE IN CO2

2020 ◽  
pp. 154-158
Author(s):  
V.A. Lisovskiy ◽  
S.V. Dudin ◽  
P.P. Platonov ◽  
V.D. Yegorenkov
Keyword(s):  
Carbon Dioxide ◽  
Breakdown Voltage ◽  
Electrode Distance ◽  
Zero Current ◽  
Dc Discharge ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Gas Breakdown ◽  
Townsend Discharge ◽  
Maximum Voltage

We report the breakdown curves and current-voltage characteristics (CVC) of the Townsend mode DC discharge we have measured in carbon dioxide. We compare the breakdown curves measured with two different techniques. With the first technique we regard as breakdown voltage the maximum voltage which we can apply across the electrodes without igniting the discharge with fixed values of the inter-electrode distance and the gas pressure. With the second technique we register the CVC of the Townsend mode in the μA-mA range and then extrapolate them to zero current. We reveal that in the nA-μA range the CVCs of the Townsend mode may have a complicated behavior due to the formation of the space charge. Therefore the second technique furnishes incorrect values of the breakdown voltage.

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