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Gas sensors

Hongcheng Liu, Qu Zhou, Qingyan Zhang, Changxiang Hong, Lingna Xu, Lingfeng Jin, Weigen Chen
The detection of partial discharge and analysis of the composition and content of sulfur hexafluoride SF₆ gas components are important to evaluate the operating state and insulation level of gas-insulated switchgear (GIS) equipment. This paper reported a novel sensing material made of pure ZnO and NiO-decorated ZnO nanoflowers which were synthesized by a facile and environment friendly hydrothermal process for the detection of SF₆ decomposition byproducts. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were used to characterize the structural and morphological properties of the prepared gas-sensitive materials...
April 21, 2017: Sensors
Hsin-Yi Li, Yen-Ho Chu
We demonstrated in this work the usefulness of solvate ionic liquids, SIL 3 and SIL 4, for chemoselective detection of amine gases on a quartz crystal microbalance. This detection of gaseous amines was achieved by nucleophilic aromatic addition reactions with super electrophilic SIL 3 or SIL 4 thin-coated on quartz chips. Starting with inexpensive reagents, functional SIL 3 and SIL 4 could be readily synthesized in two short steps with high isolated yield (81% and 77%, respectively). The QCM platform developed in this work is readily applicable and highly sensitive to low molecular weight amine gases: for propylamine gas at 10 Hz decrease in resonance frequency, the sensitivity of detection using SIL 4 was 5...
April 20, 2017: Analytical Chemistry
Víctor Pomareda, Rudys Magrans, Juan M Jiménez-Soto, Dani Martínez, Marcel Tresánchez, Javier Burgués, Jordi Palacín, Santiago Marco
We present the estimation of a likelihood map for the location of the source of a chemical plume dispersed under atmospheric turbulence under uniform wind conditions. The main contribution of this work is to extend previous proposals based on Bayesian inference with binary detections to the use of concentration information while at the same time being robust against the presence of background chemical noise. For that, the algorithm builds a background model with robust statistics measurements to assess the posterior probability that a given chemical concentration reading comes from the background or from a source emitting at a distance with a specific release rate...
April 20, 2017: Sensors
Alireza Nikfarjam, Seyedsina Hosseini, Nahideh Salehifar
In this research, a single-aligned nanofiber of pure TiO2 and Gold nano-particle (GNP)-TiO2 was fabricated using a novel electro-spinning procedure equipped with secondary electrostatic fields on highly sharp triangular and rectangular electrodes provided for gas sensing applications. The Sol used for spinning nanofiber consisted of Titanium Tetraisopropoxide (C12H28O4Ti), Acetic Acid (CH3COOH), Ethanol (C2H5OH) and Polyvinylpyrrolidone (PVP) and gold nanoparticle solution. FE-SEM, TEM, and XRD were used to characterize the single nanofiber...
April 19, 2017: ACS Applied Materials & Interfaces
Xiaonan Wu, Shunshun Xiong, Zhenghao Mao, Sheng Hu, Xinggui Long
The development of H₂ gas sensors is important for the H₂ production as fuel. In this work, a ZnO@ZIF-8 core-shell nanorods film is designed and synthesized as gas sensor via a facile solution deposition process, which shows an excellent selective response of H₂ over CO. By fine-tuning the reaction condition, the ZnO@ZIF-8 core-shell structure with a thin, fine-grain and porous ZIF-8 shell is obtained. Due to the easy H₂ penetration through ZIF-8 thin shell (~110 nm) and the increased oxygen vacancies for the complex film, the ZnO@ZIF-8 nanorods film shows a higher H₂ sensitivity than raw ZnO nanorods film...
April 19, 2017: Chemistry: a European Journal
Zengyuan Pang, Qingxin Nie, Pengfei Lv, Jian Yu, Fenglin Huang, Qufu Wei
We report a room temperature ammonia sensor with extra high response values and ideal flexibility, including polyaniline (PANI) coated titanium dioxide- silicon dioxide (TiO2-SiO2) or copper oxide- titanium dioxide- silicon dioxide (CuO-TiO2-SiO2) composite nanofibers. Such flexible inorganic TiO2-SiO2 and CuO-TiO2-SiO2 composite nanofibers were prepared by electrospinning, followed by calcination. Then in situ polymerization of aniline monomers was operated with inorganic TiO2-SiO2 and CuO-TiO2-SiO2 composite nanofibers as templates...
April 19, 2017: Nanotechnology
R Mishra, M Joshi, O Meisenberg, S Gierl, R Prajith, S D Kanse, R Rout, B K Sapra, Y S Mayya, J Tschiersch
Experiments have been carried out using the deposition-based Direct Thoron Progeny Sensors (DTPS) in a thoron experimental house. The objective was to study the thoron decay product characteristics such as the deposition velocities, spatial variability and dependence on aerosol particle concentrations. Since the deposition velocity is an important characteristic in the calibration of the DTPS, it is very important to study its dependence on aerosol concentration in a controlled environment. At low aerosol concentration (1500 particles/cm(3)) the mean effective deposition velocity was measured to be 0...
April 18, 2017: Journal of Radiological Protection: Official Journal of the Society for Radiological Protection
Jiguang Zhang, Yunfeng Zhu, Huaijun Lin, Yana Liu, Yao Zhang, Shenyang Li, Zhongliang Ma, Liquan Li
Metal hydrides (MHs) have recently been designed for hydrogen sensors, switchable mirrors, rechargeable batteries, and other energy-storage and conversion-related applications. The demands of MHs, particular fast hydrogen absorption/desorption kinetics, have brought their sizes to nanoscale. However, the nanostructured MHs generally suffer from surface passivation and low aggregation-resisting structural stability upon absorption/desorption. This study reports a novel strategy named microencapsulated nanoconfinement to realize local synthesis of nano-MHs, which possess ultrahigh structural stability and superior desorption kinetics...
April 18, 2017: Advanced Materials
Anna P M Michel, Jason Kapit, Mark F Witinski, Romain Blanchard
Methane is a powerful greenhouse gas that has both natural and anthropogenic sources. The ability to measure methane using an integrated path length approach such as an open/long-path length sensor would be beneficial in several environments for examining anthropogenic and natural sources, including tundra landscapes, rivers, lakes, landfills, estuaries, fracking sites, pipelines, and agricultural sites. Here a broadband monolithic distributed feedback-quantum cascade laser array was utilized as the source for an open-path methane sensor...
April 10, 2017: Applied Optics
Javis A Nwaboh, Zhechao Qu, Olav Werhahn, Volker Ebert
We report on an interband cascade laser (ICL)-absorption spectrometer for absolute, calibration-free, atmospheric CO amount fraction measurements, addressing direct traceability of the results. The system combines first-principles direct tunable diode laser absorption spectroscopy (dTDLAS) with a metrological validation. Using a multipath cell with 76 m path length, our detection limit is 0.5 nmol/mol at Δt=14  s. The system is highly linear (slope: 0.999±0.008) in the amount fraction range of 0.1-1000 μmol/mol and thus is interesting for industrial as well as environmental applications...
April 10, 2017: Applied Optics
Xiaoxue Wang, Sema Ermez, Hilal Goktas, Silvija Gradečak, Karen Gleason
Novel structures comprised of GaAs nanowire arrays conformally coated with conducting polymers (poly(3,4-ethylenedioxythiophene) (PEDOT) or poly(3,4-ethylenedioxythiophene-co-3-thiophene acetic acid) display both sensitivity and selectivity to a variety of volatile organic chemicals. A key feature is room temperature operation, so that neither a heater nor the power it would consume, is required. It is a distinct difference from traditional metal oxide sensors, which typically require elevated operational temperature...
April 13, 2017: Macromolecular Rapid Communications
Shen Liu, Yiping Wang, Changrui Liao, Ying Wang, Jun He, Cailing Fu, Kaiming Yang, Zhiyong Bai, Feng Zhang
We demonstrate an ultrahigh-sensitivity gas pressure sensor based on the Fabry-Perot interferometer employing a fiber-tip diaphragm-sealed cavity. The cavity is comprised of a silica capillary and ultrathin silica diaphragm with a thickness of 170 nm, with represents the thinnest silica diaphragm fabricated thus far by an electrical arc discharge technique. The resulting Fabry-Perot interferometer-based gas pressure sensor demonstrates a gas pressure sensitivity of about 12.22 nm/kPa, which is more than two orders of magnitude greater than that of a similarly configured fiber-tip air bubble sensor...
April 11, 2017: Scientific Reports
Mohammad Mahdi Doroodmand, Mohsen Askari
A novel nitrogen-doped carbon dot (N-CD) was synthesized via carbonization of citric acid in the presence of triethylenetetramine as a nitrogen source. The average size of the N-doped CDs and also the quantum yield of the synthesized N-doped CDs were both estimated to be 9 ± 2 nm and 39.5%, respectively. The applications of the synthesized carbon nanostructure as a high quantum yield fluorescence probe were initially adopted in the fabrication of a novel optical pH (acidity) sensor in both aqueous and nonaqueous environments...
May 22, 2017: Analytica Chimica Acta
Jair Ferreira, Eduardo Carvalho, Bruno V Ferreira, Cleidson de Souza, Yoshihiko Suhara, Alex Pentland, Gustavo Pessin
Driver behavior impacts traffic safety, fuel/energy consumption and gas emissions. Driver behavior profiling tries to understand and positively impact driver behavior. Usually driver behavior profiling tasks involve automated collection of driving data and application of computer models to generate a classification that characterizes the driver aggressiveness profile. Different sensors and classification methods have been employed in this task, however, low-cost solutions and high performance are still research targets...
2017: PloS One
Kazunari Shinbo, Ryo Komai, Hiroki Honda, Yasuo Ohdaira, Akira Baba, Keizo Kato, Futao Kaneko
Analysis of NH3 gas under various humidity conditions was conducted using a waveguide surface plasmon resonance (SPR) sensor with dual sensing parts. Two pairs of Ag films/sensing polymer films were prepared separately on a waveguide core of BK-7 slide glass. Poly(acrylic acid) (PAA) and poly(vinyl alcohol) (PVA) were used as sensing materials. A white light was guided through the core by illuminating the substrate edge, and the SPR property was investigated by observing the output light spectrum. The thicknesses of PAA and PVA films were adjusted to induce SPR at different wavelengths...
2017: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Stephan Steinhauer, Jerome Vernieres, Johanna Krainer, Anton Köck, Panagiotis Grammatikopoulos, Mukhles Sowwan
In situ transmission electron microscopy provides exciting opportunities to address fundamental questions and technological aspects related to functional nanomaterials, including the structure-property relationships of miniaturized electronic devices. Herein, we report the in situ chemoresistive sensing in the environmental transmission electron microscope (TEM) with a single SnO2 nanowire device, studying the impact of surface functionalization with heterogeneous nanocatalysts. By detecting toxic carbon monoxide (CO) gas at ppm-level concentrations inside the microscope column, the sensing properties of a single SnO2 nanowire were characterized before and after decoration with hybrid Fe-Pd nanocubes...
April 7, 2017: Nanoscale
Rumeng Zhao, Tianxing Wang, Mingyu Zhao, Congxin Xia, Xu Zhao, Yipeng An, Xianqi Dai
Using first-principle atomistic simulations, we focused on the electronic structures of small gas molecules (CO, H2O, NH3, NO, and NO2) adsorbed on the S-vacancy SnS2 monolayer. The results show that H2O and CO molecules were physisorbed on the S-vacancy SnS2 monolayer, whereas NH3, NO, and NO2 molecules were chemisorbed on the S-vacancy SnS2 monolayer via strong covalent bonds. Moreover, our calculations show that H2O and NH3 act as charge donors, whereas CO, NO, and NO2 gas molecules act as acceptors. Different adsorption behaviors of common gas molecules on the S-vacancy SnS2 monolayer provide a feasible way to exploit chemical gas sensors and electrical devices...
April 19, 2017: Physical Chemistry Chemical Physics: PCCP
Elena Dilonardo, Michele Penza, Marco Alvisi, Riccardo Rossi, Gennaro Cassano, Cinzia Di Franco, Francesco Palmisano, Luisa Torsi, Nicola Cioffi
Multiwalled carbon nanotube (MWCNT)-based chemiresistors were electrochemically decorated with Au and Pd nanoparticles (NPs), resulting in an improvement in the detection of gaseous pollutants as compared to sensors based on pristine MWCNTs. Electrophoresis was used to decorate MWCNTs with preformed Au or Pd NPs, thus preserving their nanometer-sized dimensions and allowing the metal content to be tuned by simply varying the deposition time. The sensing response of unmodified and metal-decorated MWCNTs was evaluated towards different gaseous pollutants (e...
2017: Beilstein Journal of Nanotechnology
Margus Kodu, Artjom Berholts, Tauno Kahro, Mati Kook, Peeter Ritslaid, Helina Seemen, Tea Avarmaa, Harry Alles, Raivo Jaaniso
Graphene has been recognized as a promising gas sensing material. The response of graphene-based sensors can be radically improved by introducing defects in graphene using, for example, metal or metal oxide nanoparticles. We have functionalised CVD grown, single-layer graphene by applying pulsed laser deposition (PLD) of V2O5 which resulted in a thin V2O5 layer on graphene with average thickness of ≈0.6 nm. From Raman spectroscopy, it was concluded that the PLD process also induced defects in graphene. Compared to unmodified graphene, the obtained chemiresistive sensor showed considerable improvement of sensing ammonia at room temperature...
2017: Beilstein Journal of Nanotechnology
Daniel Fischer, Andreas Hertwig, Uwe Beck, Volkmar Lohse, Detlef Negendank, Martin Kormunda, Norbert Esser
Background: Gas sensors are very important in several fields like gas monitoring, safety and environmental applications. In this approach, a new gas sensing concept is investigated which combines the powerful adsorption probability of metal oxide conductive sensors (MOS) with an optical ellipsometric readout. This concept shows promising results to solve the problems of cross sensitivity of the MOS concept. Results: Undoped tin oxide (SnOx) and iron doped tin oxide (Fe:SnOx) thin add-on films were prepared by magnetron sputtering on the top of the actual surface plasmon resonance (SPR) sensing gold layer...
2017: Beilstein Journal of Nanotechnology
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