SOFC Anode Process Characterization by Means of a Spot-Sampling Set-up for in-Operando Gas Analysis

AbstractRapid, high-throughput diagnostic tests are essential to decelerate the spread of the novel coronavirus disease 2019 (COVID-19) pandemic. While RT-PCR tests performed in centralized laboratories remain the gold standard, rapid point-of-care antigen tests might provide faster results. However, they are associated with markedly reduced sensitivity. Bedside breath gas analysis of volatile organic compounds detected by ion mobility spectrometry (IMS) may enable a quick and sensitive point-of-care testing alternative. In this proof-of-concept study, we investigated whether gas analysis by IMS can discriminate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from other respiratory viruses in an experimental set-up. Repeated gas analyses of air samples collected from the headspace of virus-infected in vitro cultures were performed for 5 days. A three-step decision tree using the intensities of four spectrometry peaks correlating to unidentified volatile organic compounds allowed the correct classification of SARS-CoV-2, human coronavirus-NL63, and influenza A virus H1N1 without misassignment when the calculation was performed with data 3 days post infection. The forward selection assignment model allowed the identification of SARS-CoV-2 with high sensitivity and specificity, with only one of 231 measurements (0.43%) being misclassified. Thus, volatile organic compound analysis by IMS allows highly accurate differentiation of SARS-CoV-2 from other respiratory viruses in an experimental set-up, supporting further research and evaluation in clinical studies.

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Experimental Investigation of the Air Exchange Effectiveness of Push-Pull Ventilation Devices

Energies ◽

10.3390/en13215817 ◽

2020 ◽

Vol 13 (21) ◽

pp. 5817

Author(s):

Sven Auerswald ◽

Carina Hörberg ◽

Thibault Pflug ◽

Jens Pfafferott ◽

Constanze Bongs ◽

...

Keyword(s):

Heat Dissipation ◽

Residential Buildings ◽

Air Flow ◽

Operation Mode ◽

Ventilation System ◽

Field Measurements ◽

Gas Analysis ◽

Decentralised Systems ◽

Set Up ◽

Air Exchange

The increasing installation numbers of ventilation units in residential buildings are driven by legal objectives to improve their energy efficiency. The dimensioning of a ventilation system for nearly zero energy buildings is usually based on the air flow rate desired by the clients or requested by technical regulations. However, this does not necessarily lead to a system actually able to renew the air volume of the living space effectively. In recent years decentralised systems with an alternating operation mode and fairly good energy efficiencies entered the market and following question was raised: “Does this operation mode allow an efficient air renewal?” This question can be answered experimentally by performing a tracer gas analysis. In the presented study, a total of 15 preliminary tests are carried out in a climatic chamber representing a single room equipped with two push-pull devices. The tests include summer, winter and isothermal supply air conditions since this parameter variation is missing till now for push-pull devices. Further investigations are dedicated to the effect of thermal convection due to human heat dissipation on the room air flow. In dependence on these boundary conditions, the determined air exchange efficiency varies, lagging behind the expected range 0.5 < εa < 1 in almost all cases, indicating insufficient air exchange including short-circuiting. Local air exchange values suggest inhomogeneous air renewal depending on the distance to the indoor apertures as well as the temperature gradients between in- and outdoor. The tested measurement set-up is applicable for field measurements.

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The Impact of Variable Inlet Mixture Stratification on Flame Topology and Emissions Performance of a Premixer/Swirl Burner Configuration

Journal of Combustion ◽

10.1155/2012/374089 ◽

2012 ◽

Vol 2012 ◽

pp. 1-12 ◽

Cited By ~ 1

Author(s):

P. Koutmos ◽

G. Paterakis ◽

E. Dogkas ◽

Ch. Karagiannaki

Keyword(s):

Vortex Formation ◽

Gas Analysis ◽

Large Eddy Simulations ◽

Mixing Conditions ◽

Swirl Burner ◽

Large Eddy ◽

Air Mixing ◽

Set Up ◽

The Impact ◽

Plane Disk

The work presents the assessment of a low emissions premixer/swirl burner configuration utilizing lean stratified fuel preparation. An axisymmetric, single- or double-cavity premixer, formed along one, two, or three concentric disks promotes propane-air premixing and supplies the combustion zone at the afterbody disk recirculation with a radial equivalence ratio gradient. The burner assemblies are operated with a swirl co-flow to study the interaction of the recirculating stratified flame with the surrounding swirl. A number of lean and ultra-lean flames operated either with a plane disk stabilizer or with one or two premixing cavity arrangements were evaluated over a range of inlet mixture conditions. The influence of the variation of the imposed swirl was studied for constant fuel injections. Measurements of turbulent velocities, temperatures, OH* chemiluminescence and gas analysis provided information on the performance of each burner set up. Comparisons with Large Eddy Simulations, performed with an 11-step global chemistry, illustrated the flame front interaction with the vortex formation region under the influence of the variable inlet mixture stratifications. The combined effort contributed to the identification of optimum configurations in terms of fuel consumption and pollutants emissions and to the delineation of important controlling parameters and limiting fuel-air mixing conditions.

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2D MEMS scanning LIDAR with sub-Nyquist sampling, set-up and functionality

10.1117/12.2175855 ◽

2015 ◽

Author(s):

Joachim Janes ◽

Thorsten Giese

Keyword(s):

Scanning Lidar ◽

Set Up ◽

Sampling Set

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Calibration of Gas Analysis Devices

Metrology and instruments ◽

10.33955/2307-2180(6)2019.50-53 ◽

2020 ◽

pp. 50-53

Author(s):

V. R. Kozubovsky

Keyword(s):

Measuring Equipment ◽

Large Error ◽

Metrological Certification ◽

Gas Analysis ◽

The State ◽

Point Of View ◽

Set Up ◽

Explosive Devices ◽

Metrological Parameters ◽

Calibration Interval

Gas analyzers, especially toxic and explosive devices, are usually measuring equipment. Therefore, it is very important to ensure their metrological parameters. For this purpose, their metrological certification is carried out periodically. However, this procedure is quite costly and is carried out by metrological centers that put state sealer seals and write a suitable device for operation or not. The interval of the calibration interval is usually more than 1 year and during this period the metrological parameters of the device change and it becomes unsuitable (from the point of view of metrological centers) for operation. Device developers, when writing “inter-calibration interval, for example, 1 year”, they guarantee the preservation of metrological parameters for 1 year. If a longer period has elapsed, the instrument must be set up before calibration. However, the device is customized by the developer or a qualified professional. As a rule, the owner of the appliance does not have such an opportunity and the state verifier lacks it. Therefore, it is very important that the owner of the device is able to independently check its performance. There are many methods of calibration of the instrument — for example, partial darkening of the working channel, introduction of a sealed cuvette with a certain concentration of the measured gas into the working channel, etc. [1-6]. But all of them have certain disadvantages both in terms of a large error and the possibility of their implementation in option.

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Design and development of a controlled pressure/temperature set-up forin situstudies of solid–gas processes and reactions in a synchrotron X-ray powder diffraction station

Journal of Synchrotron Radiation ◽

10.1107/s1600577514021018 ◽

2015 ◽

Vol 22 (1) ◽

pp. 42-48 ◽

Cited By ~ 8

Author(s):

Eduardo Salas-Colera ◽

Álvaro Muñoz-Noval ◽

Catherine Heyman ◽

Conchi O. Ania ◽

José B. Parra ◽

...

Keyword(s):

Powder Diffraction ◽

Gas Adsorption ◽

Processes And Reactions ◽

X Ray ◽

Experimental Station ◽

Transmission Geometry ◽

Gas Reactions ◽

In Operando ◽

Set Up

A novel set-up has been designed and used for synchrotron radiation X-ray high-resolution powder diffraction (SR-HRPD) in transmission geometry (spinning capillary) forin situsolid–gas reactions and processes in an isobaric and isothermal environment. The pressure and temperature of the sample are controlled from 10−3to 1000 mbar and from 80 to 1000 K, respectively. To test the capacities of this novel experimental set-up, structure deformation in the porous material zeolitic imidazole framework (ZIF-8) by gas adsorption at cryogenic temperature has been studied under isothermal and isobaric conditions. Direct structure deformations by the adsorption of Ar and N2gases have been observedin situ, demonstrating that this set-up is perfectly suitable for direct structural analysis underin operandoconditions. The presented results prove the feasibility of this novel experimental station for the characterization in real time of solid–gas reactions and other solid–gas processes by SR-HRPD.

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Opto-Electronic Nose Coupled to a Silicon Micro Pre-Concentrator Device for Selective Sensing of Flavored Waters

Chemosensors ◽

10.3390/chemosensors8030060 ◽

2020 ◽

Vol 8 (3) ◽

pp. 60 ◽

Cited By ~ 2

Author(s):

Sami Slimani ◽

Etienne Bultel ◽

Thomas Cubizolle ◽

Cyril Herrier ◽

Tristan Rousselle ◽

...

Keyword(s):

Detection Limit ◽

Electronic Nose ◽

Headspace Analysis ◽

Principal Component ◽

Gas Analysis ◽

Background Signal ◽

High Background ◽

Discrimination Ability ◽

Discriminant Ability ◽

Set Up

Headspace analysis of highly humid samples remains a challenge for artificial olfaction. Based on surface plasmon resonance imaging and bio-based sensors, the NeOse Pro olfactive analyzer yields multivariate data and enhances the statistical discrimination capacity of odor patterns. However, the presence of a high background signal, such as water vapor from aqueous samples, may deteriorate its discriminant ability. Recently, miniaturized pre-concentrators packed with hydrophobic adsorbent have been developed to improve the detection limit of gas analysis methods and to enhance their selectivity by reducing the water’s background signal. This work presents, for the first time, the coupling of a miniaturized silicon micro pre-concentration unit (µPC) to a bio-based opto-electronic nose (NeOse Pro). The results showed that the coupling of a silicon µPC with the NeOse Pro led to an improvement in the detection limit of n-nonane by at least a factor of 125. Additionally, principal component analysis (PCA) of eight different flavored waters showed an enhanced discrimination ability of the coupled set-up in highly humid conditions.

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Towards in operando material process characterization over many length scales

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314088287 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C1171-C1171

Author(s):

Andrew Allen ◽

Fan Zhang ◽

Lyle Levine ◽

Jan Ilavsky

Keyword(s):

Neutron Scattering ◽

Small Angle ◽

Health And Safety ◽

Phase Evolution ◽

Environmental Health And Safety ◽

Length Scales ◽

X Ray ◽

Process Characterization ◽

In Operando ◽

The Impact

The properties and performance of complex material systems are frequently controlled by phenomena that operate over many length-scales from sub-nanometers to millimeters. Understanding the behavior of such materials requires statistically-representative measurement of these effects on the structure and microstructure evolution across this entire length-scale range, over timescales that match those of the phenomena of interest. Small-angle X-ray and neutron scattering (SAXS and SANS) can address much of this need and reveal cause-and-effect phenomena acting across many length scales. This is especially true if SAXS or SANS are combined with wide-angle X-ray and neutron scattering (WAXS and WANS) diffraction measurements to follow the corresponding phase evolution. These concepts are demonstrated in several high-impact studies pursued with our collaborators, including in operando studies to measure: the effects of gas sorption on the structures and microstructures of new carbon sorbent materials [1]; precipitate formation and growth, together with associated phase transformations in advanced light-weight alloys during annealing or plastic deformation; real-time dissolution, clustering and agglomeration of silver nanoparticles in an acidic environment (relevant to environmental health and safety concerns) [2]; and even cement hydration phenomena related to concrete shrinkage. Many of these measurements were made at the ultra-small-angle X-ray scattering (USAXS) facility at the Advanced Photon Source where rapid combined USAXS/SAXS/WAXS studies are now possible under in operando conditions. Planned further development of the instrument capabilities will significantly enhance such in operando measurements, as can be demonstrated by the impact on these same studies [3].

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Application of semiconductor sensors to gas analysis

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19792598 ◽

1979 ◽

Vol 44 (9) ◽

pp. 2598-2602 ◽

Cited By ~ 1

Author(s):

Jan Michal

Keyword(s):

Gas Analysis ◽

Sensor Response ◽

Combustible Gas ◽

Semiconductor Sensors ◽

Set Up ◽

Combustible Gases

A device was set up based on semiconductor sensors, which made it possible to study the conditions of the sensor response to a change of the concentration of combustible gases and vapours in the atmosphere monitored. The conditions were established under which the method can be applied in atmosphere analysis to the determination of the concentration of a combustible gas or vapour.

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