Search query: gas source

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abstract: This paper describes the development and validation of the currently smallest aerial platform with olfaction capabilities. The developed Smelling Nano Aerial Vehicle (SNAV) is based on a lightweight commercial nano quadcopter (27 g) equipped with a custom gas sensing board that can host up to two in situ metal oxide semiconductor (MOX) gas sensors. Due to its small form factor, the SNAV is not a hazard for humans, enabling its use in public areas or inside buildings. It can autonomously carry out gas sensing missions of hazardous environments inaccessible to terrestrial robots and bigger drones, for example searching for victims and hazardous gas leaks inside pockets that form within the wreckage of collapsed buildings in the aftermath of an earthquake or explosion. The first contribution of this work is assessing the impact of the nano propellers on the MOX sensor signals at different distances to a gas source. A second contribution is adapting the 'bout' detection algorithm, proposed by Schmuker et al. (2016) to extract specific features from the derivative of the MOX sensor response, for real time operation. The third and main contribution is the experimental validation of the SNAV for gas source localization (GSL) and mapping in a large indoor environment (160 m2) with a gas source placed in challenging positions for the drone, for example hidden in the ceiling of the room or inside a power outlet box. Two GSL strategies are compared, one based on the instantaneous gas sensor response and the other one based on the bout frequency. From the measurements collected (in motion) along a predefined sweeping path we built (in less than 3 min) a 3D map of the gas distribution and identified the most likely source location. Using the bout frequency yielded on average a higher localization accuracy than using the instantaneous gas sensor response (1.38 m versus 2.05 m error) however accurate tuning of an additional parameter (the noise threshold) is required in the former case. The main conclusion of this paper is that a nano drone has the potential to perform gas sensing tasks in complex environments.
author_names: Javier Burgues

Victor Manuel Hernandez Bennetts

Achim J Lilienthal

Santiago Marco
title: Smelling Nano Aerial Vehicle for Gas Source Localization and Mapping
venue: Sensors
year: 2019

abstract: Identification and quantification of trace gas sources is a major challenge for understanding and regulating air quality and greenhouse gas emissions. Current approaches provide either continuous but localized monitoring, or quasi instantaneous "snapshot in time" regional monitoring. There is a need for emissions detection that provides both continuous and regional coverage, because sources and sinks can be episodic and spatially variable. We field deploy a dual frequency comb laser spectrometer for the first time, enabling an observing system that provides continuous detection of trace gas sources over multiple square kilometer regions. Field tests simulating methane emissions from oil and gas production demonstrate detection and quantification of a 1.6 g min 1 source (less than the average emissions from a small pneumatic controller) from a distance of 1 km, and the ability to discern two leaks among a field of many potential sources. The technology achieves the goal of detecting, quantifying, and attributing emissions sources continuously through time, over large areas, and at emissions rates ~1000x lower than current regional approaches. It therefore provides a useful tool for monitoring and mitigating undesirable sources and closes a major information gap in the atmospheric sciences.
author_names: Sean C Coburn

Caroline B Alden

Robert J Wright

Kevin C Cossel

Esther Baumann

Gar Wing Truong

Fabrizio Raphael Giorgetta

Colm Sweeney

Nathan R Newbury

K Rajendra Prasad

Ian Coddington

Gregory B Rieker
title: Regional trace gas source attribution using a field deployed dual frequency comb spectrometer
year: 2018

abstract: This paper addresses the localization of a gas emission source within a real world human environment with a mobile robot. Our approach is based on an efficient and coherent system that fuses different sensor modalities (i.e. vision and chemical sensing) to exploit, for the first time, the semantic relationships among the detected gases and the objects visually recognized in the environment. This novel approach allows the robot to focus the search on a finite set of potential gas source candidates (dynamically updated as the robot operates) while accounting for the non negligible uncertainties in the object recognition and gas classification tasks involved in the process. This approach is particularly interesting for structured indoor environments containing multiple obstacles and objects, enabling the inference of the relations between objects and between objects and gases. A probabilistic Bayesian framework is proposed to handle all these uncertainties and semantic relations, providing an ordered list of candidates to be the source. This candidate list is updated dynamically upon new sensor measurements to account for objects not previously considered in the search process. The exploitation of such probabilities together with information such as the locations of the objects, or the time needed to validate whether a given candidate is truly releasing gases, is delegated to a path planning algorithm based on Markov decision processes to minimize the search time. The system was tested in an office like scenario, both with simulated and real experiments, to enable the comparison of different path planning strategies and to validate its efficiency under real world conditions.
author_names: Javier Gonzalez Monroy

Jose-Raul Ruiz-Sarmiento

Francisco Angel Moreno

Francisco Melendez-Fernandez

Cipriano Galindo

Javier Gonzalez
title: A Semantic Based Gas Source Localization with a Mobile Robot Combining Vision and Chemical Sensing
venue: Sensors
year: 2018

abstract: The design of a flying odor compass is proposed for the localization of gas source. The compass is built on a quad rotor helicopter and contains three gas sensors. A data processing method is proposed to estimate the direction which the odor comes from. The method adopts continuous wavelet transform and modulus maxima approaches to uncover the time difference information hidden in the gas sensor signals. Experiments have demonstrated the effectiveness of this design.
author_names: Bing Luo

Jia-Ying Wang

Ming Zeng
title: A Flying Odor Compass to Autonomously Locate the Gas Source
venue: IEEE Transactions on Instrumentation and Measurement
year: 2018

abstract: The occurrence of anaerobic oxidation of methane (AOM) and trace methane oxidation (TMO) was investigated in a freshwater natural gas source. Sediment samples were taken and analyzed for potential electron acceptors coupled to AOM. Long term incubations with 13C labeled CH4 (13CH4) and different electron acceptors showed that both AOM and TMO occurred. In most conditions, 13C labeled CO2 (13CO2) simultaneously increased with methane formation, which is typical for TMO. In the presence of nitrate, neither methane formation nor methane oxidation occurred. Net AOM was measured only with sulfate as electron acceptor. Here, sulfide production occurred simultaneously with 13CO2 production and no methanogenesis occurred, excluding TMO as a possible source for 13CO2 production from 13CH4. Archaeal 16S rRNA gene analysis showed the highest presence of ANME 2a/b (ANaerobic MEthane oxidizing archaea) and AAA (AOM Associated Archaea) sequences in the incubations with methane and sulfate as compared with only methane addition. Higher abundance of ANME 2a/b in incubations with methane and sulfate as compared with only sulfate addition was shown by qPCR analysis. Bacterial 16S rRNA gene analysis showed the presence of sulfate reducing bacteria belonging to SEEP SRB1. This is the first report that explicitly shows that AOM is associated with sulfate reduction in an enrichment culture of ANME 2a/b and AAA methanotrophs and SEEP SRB1 sulfate reducers from a low saline environment.
author_names: Peer H A Timmers

Diego A Suarez-Zuluaga

Minke van Rossem

Martijn Diender

A J M Stams

Caroline M Plugge
title: Anaerobic oxidation of methane associated with sulfate reduction in a natural freshwater gas source
venue: The ISME Journal
year: 2016

abstract: Abstract The molecular composition, stable carbon and hydrogen isotopes and light hydrocarbons of the Upper Paleozoic tight gas in the Daniudi gas field in the Ordos Basin were investigated to study the geochemical characteristics. Tight gas in the Daniudi gas field displays a dryness coefficient (C1/C1 5) of 0.845 0.977 with generally positive carbon and hydrogen isotopic series, and the C7 and C5 7 light hydrocarbons of tight gas are dominated by methylcyclohexane and iso alkanes, respectively. The identification of gas origin and gas source correlation indicate that tight gas is coal type gas, and the gases reservoired in the Lower Permian Shanxi Fm. (P1s) and Lower Shihezi Fm. (P1x) had a good affinity and were derived from the P1s coal measure source rocks, whereas the gas reservoired in the Upper Carboniferous Taiyuan Fm. (C3t) was derived from the C3t coal measure source rocks. The molecular and methane carbon isotopic fractionations of natural gas support that the P1x gas was derived from the P1s source rocks. The differences of geochemical characteristics of the C3t gas from different areas in the field suggest the effect of maturity difference of the source rocks rather than the diffusive migration, and the large scale lateral migration of the C3t gas seems unlikely. Comparative study indicates that the differences of the geochemical characteristics of the P1s gases from the Yulin and Daniudi gas fields originated likely from the maturity difference of the in situ source rocks, rather than the effect of large scale lateral migration of the P1s gases.
author_names: Xiaoqi Wu

Quanyou Liu

Jianhui Zhu

Kuang Li

Guangxiang Liu

Yingbin Chen

Chunhua Ni
title: Geochemical characteristics of tight gas and gas source correlation in the Daniudi gas field, the Ordos Basin, China
year: 2017

abstract: Mobile robot olfaction systems combine gas sensors with mobility provided by robots. They relief humans of dull, dirty and dangerous tasks in applications such as search rescue or environmental monitoring. We address gas source localization and especially the problem of minimizing exploration time of the robot, which is a key issue due to energy constraints. We propose an active search approach for robots equipped with MOX gas sensors and an anemometer, given an occupancy map. Events of rapid change in the MOX sensor signal "bouts" are used to estimate the distance to a gas source. The wind direction guides a Gaussian regression, which interpolates distance estimates. The contributions of this paper are two fold. First, we extend previous work on gas source distance estimation with MOX sensors and propose a modification to cope better with turbulent conditions. Second, we introduce a novel active search gas source localization algorithm and validate it in a real world environment.
author_names: Mikel Vuka

Erik Schaffernicht

Michael Schmuker

Victor Manuel Hernandez Bennetts

Francesco Amigoni

Achim J Lilienthal
title: Exploration and localization of a gas source with MOX gas sensors on a mobile robot A Gaussian regression bout amplitude approach
venue: 2017 ISOCS/IEEE International Symposium on Olfaction and Electronic Nose (ISOEN)
year: 2017

abstract: Abstract Estimating the distance of a gas source is important in many applications of chemical sensing, like e.g. environmental monitoring, or chemically guided robot navigation. If an estimation of the gas concentration at the source is available, source proximity can be estimated from the time averaged gas concentration at the sensing site. However, in turbulent environments, where fast concentration fluctuations dominate, comparably long measurements are required to obtain a reliable estimate. A lesser known feature that can be exploited for distance estimation in a turbulent environment lies in the relationship between source proximity and the temporal variance of the local gas concentration the farther the source, the more intermittent are gas encounters. However, exploiting this feature requires measurement of changes in gas concentration on a comparably fast time scale, that have up to now only been achieved using photo ionisation detectors. Here, we demonstrate that by appropriate signal processing, off the shelf metal oxide sensors are capable of extracting rapidly fluctuating features of gas plumes that strongly correlate with source distance. We show that with a straightforward analysis method it is possible to decode events of large, consistent changes in the measured signal, so called 'bouts' The frequency of these bouts predicts the distance of a gas source in wind tunnel experiments with good accuracy. In addition, we found that the variance of bout counts indicates cross wind offset to the centreline of the gas plume. Our results offer an alternative approach to estimating gas source proximity that is largely independent of gas concentration, using off the shelf metal oxide sensors. The analysis method we employ demands very few computational resources and is suitable for low power microcontrollers.
author_names: Michael Schmuker

Viktor Bahr

Ramon Huerta
title: Exploiting plume structure to decode gas source distance using metal oxide gas sensors
year: 2016

abstract: Gas source localization (GSL) with mobile robots is a challenging task due to the unpredictable nature of gas dispersion, the limitations of the currents sensing technologies, and the mobility constraints of ground based robots. This work proposes an integral solution for the GSL task, including source declaration. We present a novel pseudo gradient based plume tracking algorithm and a particle filter based source declaration approach, and apply it on a gas sensitive micro drone. We compare the performance of the proposed system in simulations and real world experiments against two commonly used tracking algorithms adapted for aerial exploration missions.
author_names: Patrick P Neumann

Victor Manuel Hernandez Bennetts

Achim J Lilienthal

Matthias Bartholmai

Jochen H Schiller
title: Gas source localization with a micro drone using bio inspired and particle filter based algorithms
venue: Adv. Robotics
year: 2013

abstract: RATIONALE High precision stable isotope measurements in gas source isotope ratio mass spectrometry are generally carried out by repeated comparison of the composition of an unknown sample with that of a working gas (WG) through a dual inlet (DI) Due to the established DI protocols, however, most of the sample gas is wasted rather than measured, which is a major problem when sample size is limited. Here we propose a new methodology allowing the measurement of a much larger portion of the available sample. METHODS We tested a new measurement protocol, the long integration dual inlet (LIDI) method, which consists of a single measurement of the sample for 200 to 600 seconds followed by a single measurement of the WG. The isotope ratios of the sample are calculated by comparison of the beam ratios of the WG and sample at equivalent intensities of the major ion beam. RESULTS Three isotopically very different CO2 samples were analyzed. The LIDI measurements of large samples (50 to 100 umol of CO2) measured at quasi constant beam sizes, and of small samples (1.5 to 2 umol of CO2) measured in micro volume mode, generated results that are indistinguishable from the standard DI measurements for carbon, oxygen and clumped isotope compositions. The external precision of D47 using the LIDI protocol 0.007%0) is similar to that of the state of the art DI measurements. CONCLUSIONS For traditional and clumped isotope measurements of CO2, the LIDI protocol allows the measurement of a much larger portion of the sample gas rather than only ~20% of it. In addition, the sample can be measured at higher signal intensity and for longer time, allowing the measurement of smaller samples while preserving precision. We suggest that other gases commonly used for stable isotope measurements with gas source mass spectrometry would also benefit from this new protocol.
author_names: Bin Hu

Jens Radke

H J Schluter

Frank Heine

Liping Zhou

Stefano Michele Bernasconi
title: A modified procedure for gas source isotope ratio mass spectrometry: the long integration dual inlet (LIDI) methodology and implications for clumped isotope measurements.
venue: Rapid communications in mass spectrometry RCM
year: 2014