Sensing Materials for the Detection of Chlorine Gas in Embedded Piezoresistive Microcantilever Sensors

2009 ◽  
Vol 1190 ◽  
Author(s):  
Timothy L. Porter ◽  
Tim Vail ◽  
Amanda Wooley ◽  
Richard Venedam
Keyword(s):  
High Temperature ◽  
Composite Materials ◽  
Hydrogen Fluoride ◽  
Mesh Networks ◽  
Microcantilever Sensors ◽  
Radio Transmitter ◽  
Hydrogel Matrix ◽  
Chlorine Gas ◽  
Volatile Organic ◽  
Different Types

AbstractEmbedded piezoresistive microcantilever (EPM) sensors provide a small, simple and robust platform for the detection of many different types of analytes. These inexpensive sensors may be deployed in battery-powered handheld units, or interfaced to small, battery-powered radio transmitter-receivers (motes), for deployment in mesh networks of many sensors. Previously, we have demonstrated the use of EPM sensors in the detection of hydrogen fluoride gas, organophosphate nerve agents, volatile organic compounds (VOC’s), chlorinated hydrocarbons in water, and others. Here, we report on the design of EPM sensors functionalized for the detection of chlorine gas, or Cl2. We have constructed EPM sensors using composite materials consisting of a polymer or hydrogel matrix loaded with agents specific for the detection of Cl2 such as NaI. These materials were tested in both controlled laboratory conditions and in outdoor releases. Stability of the sensing materials under conditions of high temperature were also studied. Results are presented for gas exposures ranging from 1000 ppm to 20 ppm.

scholarly journals GERMINATION AND VIGOUR IN SEEDS OF THE COWPEA IN RESPONSE TO SALT AND HEAT STRESS

2019 ◽  
Vol 32 (1) ◽  
pp. 143-151 ◽  
Author(s):  
Luma Rayane de Lima Nunes ◽  
Paloma Rayane Pinheiro ◽  
Charles Lobo Pinheiro ◽  
Kelly Andressa Peres Lima ◽  
Alek Sandro Dutra
Keyword(s):  
Salt Stress ◽  
Heat Stress ◽  
High Temperature ◽  
Low Temperature ◽  
Vigna Unguiculata ◽  
Salt Concentration ◽  
Dry Weight ◽  
Germination Percentage ◽  
Different Types ◽  
Different Temperatures

ABSTRACT Salinity is prejudicial to plant development, causing different types of damage to species, or even between genotypes of the same species, with the effects being aggravated when combined with other types of stress, such as heat stress. The aim of this study was to evaluate the tolerance of cowpea genotypes (Vigna unguiculata L. Walp.) to salt stress at different temperatures. Seeds of the Pujante, Epace 10 and Marataoã genotypes were placed on paper rolls (Germitest®) moistened with different salt concentrations of 0.0 (control), 1.5, 3.0, 4.5 and 6.0 dS m-1, and placed in a germination chamber (BOD) at temperatures of 20, 25, 30 and 35°C. The experiment was conducted in a completely randomised design, in a 3 × 4 × 5 scheme of subdivided plots, with four replications per treatment. The variables under analysis were germination percentage, first germination count, shoot and root length, and total seedling dry weight. At temperatures of 30 and 35°C, increases in the salt concentration were more damaging to germination in the Epace 10 and Pujante genotypes, while for the Marataoã genotype, damage occurred at the temperature of 20°C. At 25°C, germination and vigour in the genotypes were higher, with the Pujante genotype proving to be more tolerant to salt stress, whereas Epace 10 and Marataoã were more tolerant to high temperatures. Germination in the cowpea genotypes was more sensitive to salt stress when subjected to heat stress caused by the low temperature of 20°C or high temperature of 35°C.

scholarly journals High-Temperature Synthesis of Metal–Matrix Composites (Ni-Ti)-TiB2

2021 ◽  
Vol 11 (5) ◽  
pp. 2426
Author(s):  
Vladimir Promakhov ◽  
Alexey Matveev ◽  
Nikita Schulz ◽  
Mikhail Grigoriev ◽  
Andrey Olisov ◽  
...  
Keyword(s):  
High Temperature ◽  
Composite Materials ◽  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Metal Matrix ◽  
Average Particle Size ◽  
Synthesis Process ◽  
Average Particle ◽  
Temperature Synthesis ◽  
High Temperature Synthesis

Currently, metal–matrix composite materials are some of the most promising types of materials, and they combine the advantages of a metal matrix and reinforcing particles/fibres. Within the framework of this article, the high-temperature synthesis of metal–matrix composite materials based on the (Ni-Ti)-TiB2 system was studied. The selected approaches make it possible to obtain composite materials of various compositions without contamination and with a high degree of energy efficiency during production processes. Combustion processes in the samples of a 63.5 wt.% NiB + 36.5 wt.% Ti mixture and the phase composition and structure of the synthesis products were researched. It has been established that the synthesis process in the samples proceeds via the spin combustion mechanism. It has been shown that self-propagating high-temperature synthesis (SHS) powder particles have a composite structure and consist of a Ni-Ti matrix and TiB2 reinforcement inclusions that are uniformly distributed inside it. The inclusion size lies in the range between 0.1 and 4 µm, and the average particle size is 0.57 µm. The obtained metal-matrix composite materials can be used in additive manufacturing technologies as ligatures for heat-resistant alloys, as well as for the synthesis of composites using traditional methods of powder metallurgy.

High‐temperature performance and cross‐linking mechanism of different types of gel systems in saline environment

2021 ◽  
pp. 51452
Author(s):  
Jianbin Liu ◽  
Liguo Zhong ◽  
Zijuan Cao ◽  
Tongchun Hao ◽  
Yigang Liu ◽  
...  
Keyword(s):  
High Temperature ◽  
Cross Linking ◽  
Saline Environment ◽  
Temperature Performance ◽  
Different Types

Refining the high-temperature strength characteristics of composite materials under bending

1999 ◽  
Vol 31 (1) ◽  
pp. 105-106
Author(s):  
A. V. Bogomolov ◽  
V. A. Borisenko ◽  
V. K. Fedchuk
Keyword(s):  
High Temperature ◽  
Composite Materials ◽  
Strength Characteristics ◽  
High Temperature Strength

scholarly journals High- and low-temperature pyrolysis profiles describe volatile organic compound emissions from western US wildfire fuels

2018 ◽  
Author(s):  
Kanako Sekimoto ◽  
Abigail R. Koss ◽  
Jessica B. Gilman ◽  
Vanessa Selimovic ◽  
Matthew M. Coggon ◽  
...  
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Biomass Burning ◽  
Ponderosa Pine ◽  
Fine Particles ◽  
Voc Emissions ◽  
Western Us ◽  
Volatile Organic ◽  
Low Temperature Pyrolysis ◽  
Pyrolysis Processes

Abstract. Biomass burning is a large source of volatile organic compounds (VOCs) and many other trace species to the atmosphere, which can act as precursors to the formation of secondary pollutants such as ozone and fine particles. Measurements collected with a proton-transfer-reaction time-of-flight mass spectrometer during the FIREX 2016 laboratory intensive were analyzed with Positive Matrix Factorization (PMF), in order to understand the instantaneous variability in VOC emissions from biomass burning, and to simplify the description of these types of emissions. Despite the complexity and variability of emissions, we found that a solution including just two emission profiles, which are mass spectral representations of the relative abundances of emitted VOCs, explained on average 85 % of the VOC emissions across various fuels representative of the western US (including various coniferous and chaparral fuels). In addition, the profiles were remarkably similar across almost all of the fuel types tested. For example, the correlation coefficient r of each profile between Ponderosa pine (coniferous tree) and Manzanita (chaparral) is higher than 0.9. We identified the two VOC profiles as resulting from high-temperature and low-temperature pyrolysis processes known to form VOCs in biomass burning. High-temperature and low-temperature pyrolysis processes do not correspond exactly to the commonly used flaming and smoldering categories as described by modified combustion efficiency (MCE). The average atmospheric properties (e.g. OH reactivity, volatility, etc.) of the high- and low-temperature profiles are significantly different. We also found that the two VOC profiles can describe previously reported VOC data for laboratory and field burns. This indicates that the high- and low-temperature pyrolysis profiles could be widely useful to model VOC emissions from many types of biomass burning in the western US, with a few exceptions such as burns of duff and rotten wood.

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