scholarly journals A versatile, refrigerant- and cryogen-free cryofocusing–thermodesorption unit for preconcentration of traces gases in air

2016 ◽  
Vol 9 (11) ◽  
pp. 5265-5279 ◽  
Author(s):  
Florian Obersteiner ◽  
Harald Bönisch ◽  
Timo Keber ◽  
Simon O'Doherty ◽  
Andreas Engel
Keyword(s):  
Rapid Heating ◽  
Ambient Air ◽  
In Situ Monitoring ◽  
Gas Chromatography Mass Spectrometry ◽  
Research Station ◽  
Vacuum Insulation ◽  
Laboratory Operation ◽  
And Performance ◽  
Set Up

Abstract. We present a compact and versatile cryofocusing–thermodesorption unit, which we developed for quantitative analysis of halogenated trace gases in ambient air. Possible applications include aircraft-based in situ measurements, in situ monitoring and laboratory operation for the analysis of flask samples. Analytes are trapped on adsorptive material cooled by a Stirling cooler to low temperatures (e.g. −80 °C) and subsequently desorbed by rapid heating of the adsorptive material (e.g. +200 °C). The set-up involves neither the exchange of adsorption tubes nor any further condensation or refocusing steps. No moving parts are used that would require vacuum insulation. This allows for a simple and robust design. Reliable operation is ensured by the Stirling cooler, which neither contains a liquid refrigerant nor requires refilling a cryogen. At the same time, it allows for significantly lower adsorption temperatures compared to commonly used Peltier elements. We use gas chromatography – mass spectrometry (GC–MS) for separation and detection of the preconcentrated analytes after splitless injection. A substance boiling point range of approximately −80 to +150 °C and a substance mixing ratio range of less than 1 ppt (pmol mol−1) to more than 500 ppt in preconcentrated sample volumes of 0.1 to 10 L of ambient air is covered, depending on the application and its analytical demands. We present the instrumental design of the preconcentration unit and demonstrate capabilities and performance through the examination of analyte breakthrough during adsorption, repeatability of desorption and analyte residues in blank tests. Examples of application are taken from the analysis of flask samples collected at Mace Head Atmospheric Research Station in Ireland using our laboratory GC–MS instruments and by data obtained during a research flight with our in situ aircraft instrument GhOST-MS (Gas chromatograph for the Observation of Tracers – coupled with a Mass Spectrometer).

scholarly journals A versatile, refrigerant-free cryofocusing-thermodesorption unit for preconcentration of traces gases in air

2016 ◽  
Author(s):  
F. Obersteiner ◽  
H. Bönisch ◽  
T. Keber ◽  
S. O'Doherty ◽  
A. Engel
Keyword(s):  
Rapid Heating ◽  
Ambient Air ◽  
In Situ Monitoring ◽  
Gas Chromatography Mass Spectrometry ◽  
Research Station ◽  
Stage Design ◽  
Vacuum Insulation ◽  
Laboratory Operation ◽  
And Performance

Abstract. We present a compact and versatile cryofocusing thermodesorption unit, which we developed for quantitative analysis of halogenated trace gases in ambient air. Possible applications include aircraft-based in-situ measurements, in situ monitoring and laboratory operation for the preconcentration of analytes from flask samples. Analytes are trapped on adsorptive material cooled by a Stirling cooler to low temperatures (e.g. −80 °C) and desorbed subsequently by rapid heating of the adsorptive material (e.g. +200 °C). The setup neither involves exchange of adsorption tubes nor any further condensation or refocusation steps. No moving parts are used that would require vacuum insulation. This allows a simple and robust single stage design. Reliable operation is ensured by the Stirling cooler, which does not require refilling of a liquid refrigerant while allowing significantly lower adsorption temperatures compared to commonly used Peltier elements. We use gas chromatography mass spectrometry for separation and detection of the preconcentrated analytes after splitless injection. A substance boiling point range of approximately −80 °C to +150 °C and a substance mixing ratio range of less than 1 ppt (pmol mol−1) to more than 500 ppt in preconcentrated sample volumes of 0.1 to 10 L of ambient air is covered, depending on the application and its analytical demands. We present the instrumental design of the preconcentration unit and demonstrate capabilities and performance through the examination of injection quality, analyte breakthrough and analyte residues in blank tests. Application examples are given by the analysis of flask samples collected at Mace Head Atmospheric Research Station in Ireland using our laboratory GC TOFMS instrument and by data obtained during a research flight with our in-situ aircraft instrument GhOST MS.

scholarly journals The influence of chemical parameters on the in-situ metal carbonyl complex formation studied with the fast on-line reaction apparatus (FORA)

2021 ◽  
Vol 109 (4) ◽  
pp. 243-260 ◽  
Author(s):  
Yves Wittwer ◽  
Robert Eichler ◽  
Dominik Herrmann ◽  
Andreas Türler
Keyword(s):  
Metal Carbonyl ◽  
Ambient Air ◽  
Single Atom ◽  
Carbonyl Complex ◽  
Carbonyl Complexes ◽  
On Line ◽  
Carrier Gases ◽  
And Performance ◽  
Atom Chemistry

Abstract A new setup named Fast On-line Reaction Apparatus (FORA) is presented which allows for the efficient investigation and optimization of metal carbonyl complex (MCC) formation reactions under various reaction conditions. The setup contains a 252Cf-source producing short-lived Mo, Tc, Ru and Rh isotopes at a rate of a few atoms per second by its 3% spontaneous fission decay branch. Those atoms are transformed within FORA in-situ into volatile metal carbonyl complexes (MCCs) by using CO-containing carrier gases. Here, the design, operation and performance of FORA is discussed, revealing it as a suitable setup for performing single-atom chemistry studies. The influence of various gas-additives, such as CO2, CH4, H2, Ar, O2, H2O and ambient air, on the formation and transport of MCCs was investigated. O2, H2O and air were found to harm the formation and transport of MCCs in FORA, with H2O being the most severe. An exception is Tc, for which about 130 ppmv of H2O caused an increased production and transport of volatile compounds. The other gas-additives were not influencing the formation and transport efficiency of MCCs. Using an older setup called Miss Piggy based on a similar working principle as FORA, it was additionally investigated if gas-additives are mostly affecting the formation or only the transport stability of MCCs. It was found that mostly formation is impacted, as MCCs appear to be much less sensitive to reacting with gas-additives in comparison to the bare Mo, Tc, Ru and Rh atoms.

Smart Sensor Technologies for Performance Optimization of Power Generating Assets

2019 ◽  
Author(s):  
Komandur Sunder Raj
Keyword(s):  
Real Time ◽  
Wireless Sensors ◽  
In Situ Monitoring ◽  
Operating Costs ◽  
Embedded Sensors ◽  
Harsh Environments ◽  
Smart Sensor ◽  
And Performance ◽  
Combustion Monitoring

Abstract Significant research is ongoing on several fronts in smart sensor technologies for optimizing the performance of power generating assets. The initiatives include: 1. Real-time models with advanced computational algorithms, embedded intelligence at sensor and component level for reducing operating costs, improving efficiencies, and lowering emissions. 2. Optical sapphire sensors for monitoring operation and performance of critical components in harsh environments, for improving accuracy of measurements in combustion monitoring, and lowering operating costs. 3. Wireless technologies using (a) microwave acoustic sensors for real-time monitoring of equipment in high temperature/pressure environments (b) integrated gas/temperature acoustic sensors for combustion monitoring in diverse harsh environment locations to improve combustion efficiency, reduce emissions, and lower maintenance costs (c) sensors for sensing temperature, strain and soot accumulation inside coal-fired boilers for detailed condition monitoring, better understanding of combustion and heat exchange processes, improved designs, more efficient operation. 4. Distributed optical fiber sensing system for real-time monitoring and optimization of high temperature profiles for improving efficiency and lowering emissions. 5. Smart parts with embedded sensors for in situ monitoring of multiple parameters in existing and new facilities. 6. Optimizing advanced 3D manufacturing processes for embedded sensors in components for harsh environments to reduce costs and improve efficiency of power generation facilities with carbon capture capabilities. 7. New energy-harvesting materials for powering wireless sensors in harsh environments, improving reliability of wireless sensors in demanding environments, and in-situ monitoring and performance of devices and systems. 8. Real-time, accurate and reliable monitoring of temperature at distributed locations of sensors in harsh environments for improving operations and reducing operating costs. 9. Algorithms and methodologies for designing control systems utilizing distributed intelligence for optimal control of power generation facilities. 10. Gas sensors for monitoring high temperatures in harsh environments for lowering operating costs and better control of operations. 11. Optimizing placement of smart sensors in networks for cognitive behavior and self-learning. This paper provides an overview of the initiatives in smart sensor technologies and their applications in optimizing the performance of power generating facilities.

scholarly journals In-Situ Analysis of Essential Fragrant Oils Using a Portable Mass Spectrometer

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Fred P. M. Jjunju ◽  
Stamatios Giannoukos ◽  
Alan Marshall ◽  
Stephen Taylor
Keyword(s):  
Mass Spectrometer ◽  
Direct Analysis ◽  
Ambient Air ◽  
In Situ Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Standard Samples ◽  
Active Compounds ◽  
Portable Mass Spectrometer ◽  
Methyl Butanoate

A portable mass spectrometer was coupled to a direct inlet membrane (DIM) probe and applied to the direct analysis of active fragrant compounds (3-methylbutyl acetate, 2-methyl-3-furanthiol, methyl butanoate, and ethyl methyl sulfide) in real time. These fragrant active compounds are commonly used in the formulation of flavours and fragrances. Results obtained show that the portable mass spectrometer with a direct membrane inlet can be used to detect traces of the active fragrant compounds in complex mixtures such as essential fragrant oils and this represents a novel in-situ analysis methodology. Limits of detection (LOD) in the sub-ppb range (< 2.5 pg) are demonstrated. Standard samples in the gaseous phase presented very good linearity with RSD % at 5 to 7 for the selected active fragrant compounds (i.e., isoamyl acetate, 2-methyl-3-furanthiol, methyl butanoate, and methyl ethyl sulphide). The rise and fall times of the DIM probe are in the ranges from 15 to 31 seconds and 23 to 41 seconds, respectively, for the standard model compounds analysed. The identities of the fragrance active compounds in essential oil samples (i.e., banana, tangerine, papaya, and blueberry muffin) were first identified by comparison with a standard fragrance compounds mixture using their major fragment peaks, the NIST standard reference library, and gas chromatography mass spectrometry (GC-MS) analysis. No sample preparation is required for analysis using a portable mass spectrometer coupled to a DIM probe, so the cycle time from ambient air sampling to the acquisition of the results is at least 65 seconds.

scholarly journals Metal and Polymeric Strain Gauges for Si-Based, Monolithically Fabricated Organs-on-Chips

Micromachines ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 536 ◽  
Author(s):  
William F. Quirós-Solano ◽  
Nikolas Gaio ◽  
Cinzia Silvestri ◽  
Gregory Pandraud ◽  
Ronald Dekker ◽  
...  
Keyword(s):  
Mechanical Strain ◽  
Polymeric Materials ◽  
In Situ Monitoring ◽  
Strain Gauges ◽  
Heart Cells ◽  
Custom Made ◽  
And Performance ◽  
On Chip ◽  
Set Up

Organ-on-chip (OOC) is becoming the alternative tool to conventional in vitro screening. Heart-on-chip devices including microstructures for mechanical and electrical stimulation have been demonstrated to be advantageous to study structural organization and maturation of heart cells. This paper presents the development of metal and polymeric strain gauges for in situ monitoring of mechanical strain in the Cytostretch platform for heart-on-chip application. Specifically, the optimization of the fabrication process of metal titanium (Ti) strain gauges and the investigation on an alternative material to improve the robustness and performance of the devices are presented. The transduction behavior and functionality of the devices are successfully proven using a custom-made set-up. The devices showed resistance changes for the pressure range (0–3 kPa) used to stretch the membranes on which heart cells can be cultured. Relative resistance changes of approximately 0.008% and 1.2% for titanium and polymeric strain gauges are respectively reported for membrane deformations up to 5%. The results demonstrate that both conventional IC metals and polymeric materials can be implemented for sensing mechanical strain using robust microfabricated organ-on-chip devices.

Evidence of selection for effective nodulation in the Trifolium spp. symbiosis with Rhizobium leguminosarum biovar trifolii

2005 ◽  
Vol 45 (3) ◽  
pp. 189 ◽  
Author(s):  
R. J. Yates ◽  
J. G. Howieson ◽  
D. Real ◽  
W. G. Reeve ◽  
A. Vivas-Marfisi ◽  
...  
Keyword(s):  
Rhizobium Leguminosarum ◽  
Acid Soil ◽  
Acid Soils ◽  
Nodule Occupancy ◽  
Rhizobium Strains ◽  
Natural Grasslands ◽  
The Mediterranean ◽  
And Performance ◽  
Set Up

The pasture-breeding program to improve production in the natural grasslands in Uruguay has acknowledged that indigenous Rhizobium strains are incompatible with introduced Mediterranean clovers. In an attempt to understand and overcome this problem, a cross-row experiment was set up in 1999 in a basaltic, acid soil in Glencoe, Uruguay, to follow the survival and performance of 9 exotic strains of Rhizobium leguminosarum bv. trifolii. This paper reports on the ability of the introduced strains to compete for nodule occupancy of Mediterranean clover hosts and impacts of the introduced strains on the productivity of the indigenous Uruguayan clover Trifolium polymorphum. Strain WSM1325 was a superior inoculant and remained highly persistent and competitive for the effective symbiosis with the Mediterranean hosts, T. purpureum and T. repens, in the Uruguayan environment in the third year of the experiment. The Mediterranean hosts (T. purpureum and T. repens) nodulated with the introduced strains but did not nodulate with any indigenous R. leguminosarum bv. trifolii typed from nodules of T. polymorphum. Conversely, there were no nodules on the Uruguayan host T. polymorphum that contained introduced R. leguminosarum bv. trifolii. These results reveal the establishment of effective symbioses between strains of R. leguminosarum bv. trifolii and clover even though the soil contained ineffective R. leguminosarum bv. trifolii for all hosts. We believe our results are the first reported example of ‘selective’ nodulation for an effective symbiosis in situ with annual and perennial clovers in acid soils.

scholarly journals Evaluation of a cavity ring-down spectrometer for in situ observations of <sup>13</sup>CO<sub>2</sub>

2013 ◽  
Vol 6 (2) ◽  
pp. 301-308 ◽  
Author(s):  
F. R. Vogel ◽  
L. Huang ◽  
D. Ernst ◽  
L. Giroux ◽  
S. Racki ◽  
...  
Keyword(s):  
Co2 Concentration ◽  
Ambient Air ◽  
In Situ Monitoring ◽  
Wide Spread ◽  
Isotope Ratio Mass Spectrometer ◽  
In Situ Observations ◽  
One Year ◽  
Cavity Ring Down

Abstract. With the emergence of wide-spread application of new optical techniques to monitor δ13C in atmospheric CO2 there is a growing need to ensure well-calibrated measurements. We characterized one commonly available instrument, a cavity ring-down spectrometer (CRDS) system used for continuous in situ monitoring of atmospheric 13CO2. We found no dependency of δ13C on the CO2 concentration in the range of 303–437 ppm. We designed a calibration scheme according to the diagnosed instrumental drifts and established a quality assurance protocol. We find that the repeatability (1-σ) of measurements is 0.25‰ for 10 min and 0.15‰ for 20 min integrated averages, respectively. Due to a spectral overlap, our instrument displays a cross-sensitivity to CH4 of 0.42 ± 0.024‰ ppm−1. Our ongoing target measurements yield standard deviations of δ13C from 0.22‰ to 0.28‰ for 10 min averages. We furthermore estimate the reproducibility of our system for ambient air samples from weekly measurements of a long-term target gas to be 0.18‰. We find only a minuscule offset of 0.002 ± 0.025‰ between the CRDS and Environment Canada's isotope ratio mass spectrometer (IRMS) results for four target gases used over the course of one year.

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