| 1. |
- Quantin-Nataf, C., et al.
(author)
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The Complex Exhumation History of Jezero Crater Floor Unit and Its Implication for Mars Sample Return
- 2023
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In: Journal of Geophysical Research: Planets. - 2169-9097. ; 128:6
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Journal article (peer-reviewed)abstract
- During the first year of NASA's Mars 2020 mission, Perseverance rover has investigated the dark crater floor unit of Jezero crater and four samples of this unit have been collected. The focus of this paper is to assess the potential of these samples to calibrate the crater-based Martian chronology. We first review the previous estimation of crater-based model age of this unit. Then, we investigate the impact crater density distribution across the floor unit. It reveals that the crater density is heterogeneous from areas which have been exposed to the bombardment during the last 3 Ga to areas very recently exposed to bombardment. It suggests a complex history of exposure to impact cratering. We also display evidence of several remnants of deposits on the top of the dark floor unit across Jezero below which the dark floor unit may have been buried. We propose the following scenario of burying/exhumation: the dark floor unit would have been initially buried below a unit that was a few tens of meters thick. This unit then gradually eroded away due to Aeolian processes from the northeast to the west, resulting in uneven exposure to impact bombardment over 3 Ga. A cratering model reproducing this scenario confirms the feasibility of this hypothesis. Due to the complexity of its exposure history, the Jezero dark crater floor unit will require additional detailed analysis to understand how the Mars 2020 mission samples of the crater floor can be used to inform the Martian cratering chronology.
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| 2. |
- Centeno, R., et al.
(author)
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External cavity diode laser-based detection of trace gases with NICE-OHMS using current modulation
- 2015
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In: Optics Express. - 1094-4087. ; 23:5, s. 6277-6282
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Journal article (peer-reviewed)abstract
- We combine an external cavity diode laser with noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS) using current modulation. With a finesse of 1600, we demonstrate noise equivalent absorption sensitivities of 4.1 x 10(-10) cm(-1) Hz(-1/2), resulting in sub-ppbv detection limits for Doppler-broadened transitions of CH4 at 6132.3 cm(-1), C2H2 at 6578.5 cm(-1) and HCN at 6541.7 cm(-1). The system is used for hydrogen cyanide detection from sweet almonds.
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| 3. |
- Cristescu, S. M., et al.
(author)
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Methods of NO detection in exhaled breath
- 2013
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In: Journal of Breath Research. - : IOP Publishing. - 1752-7155 .- 1752-7163. ; 7:1, s. 017104-
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Journal article (peer-reviewed)abstract
- There is still an unexplored potential for exhaled nitric oxide (NO) in many clinical applications. This study presents an overview of the currently available methods for monitoring NO in exhaled breath and the use of the modelling of NO production and transport in the lung in clinical practice. Three technologies are described, namely chemiluminescence, electrochemical sensing and laser-based detection with their advantages and limitations. Comparisons are made in terms of sensitivity, time response, size, costs and suitability for clinical purposes. The importance of the flow rate for NO sampling is discussed from the perspective of the recent recommendations for standardized procedures for online and offline NO measurement. The measurement of NO at one flow rate, such as 50 ml s(-1), can neither determine the alveolar site/peripheral contribution nor quantify the difference in NO diffusion from the airways walls. The use of NO modelling (linear or non-linear approach) can solve this problem and provide useful information about the source of NO. This is of great value in diagnostic procedures of respiratory diseases and in treatment with anti-inflammatory drugs.
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| 4. |
- Mandon, J., et al.
(author)
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A photonic microsystem for hydrocarbon gas analysis by mid-infrared absorption spectroscopy
- 2017
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In: Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS). - 1084-6999. ; , s. 1052-1055
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Conference paper (peer-reviewed)abstract
- This paper demonstrates the functional integration of a linear variable optical filter (LVOF) and a gas cell at the wafer level, i.e. a gas-filled LVOF, where the resonator cavity of the filter is also used for storing the gas sample. A mm-level effective optical absorption path length is achieved from a μm-level physical path length, by exploiting multiple reflections from highly reflective Bragg mirrors and the high-order operation of the filter. The wideband spectral response of the device is ensured by using a tapered cavity, where the cavity length changes linearly along the length of the filter. Therefore, combined with a detector array and a light source, the gas-filled LVOF enables wideband operation and long absorption path in a single MEMS device, thus ensuring a highly sensitive on-chip gas absorption microspectrometer.
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| 5. |
- Mandon, Julien, et al.
(author)
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Exhaled nitric oxide monitoring by quantum cascade laser : comparison with chemiluminescent and electrochemical sensors
- 2012
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In: Journal of Biomedical Optics. - 1083-3668 .- 1560-2281. ; 17:1, s. 017003-
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Journal article (peer-reviewed)abstract
- Fractional exhaled nitric oxide (FENO ) is considered an indicator in the diagnostics and management of asthma. In this study we present a laser-based sensor for measuring FENO . It consists of a quantum cascade laser (QCL) combined with a multi-pass cell and wavelength modulation spectroscopy for the detection of NO at the sub-part-per-billion by volume (ppbv, 1∶10-9) level. The characteristics and diagnostic performance of the sensor were assessed. A detection limit of 0.5 ppbv was demonstrated with a relatively simple design. The QCL-based sensor was compared with two market sensors, a chemiluminescent analyzer (NOA 280, Sievers) and a portable hand-held electrochemical analyzer (MINO®, Aerocrine AB, Sweden). FENO from 20 children diagnosed with asthma and treated with inhaled corticosteroids were measured. Data were found to be clinically acceptable within 1.1 ppbv between the QCL-based sensor and chemiluminescent sensor and within 1.7 ppbv when compared to the electrochemical sensor. The QCL-based sensor was tested on healthy subjects at various expiratory flow rates for both online and offline sampling procedures. The extended NO parameters, i.e. the alveolar region, airway wall, diffusing capacity, and flux were calculated and showed a good agreement with the previously reported values.
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| 6. |
- Rådsten-Ekman, Maria, et al.
(author)
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Case-study evaluation of a low and vegetated noise barrier in an urban public space
- 2011
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In: Proceedings of Inter-Noise 2011. - Osaka, Japan: : The Institute of Noise Control Engineering of Japan and the Acoustical Society of Japan.
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Conference paper (other academic/artistic)abstract
- To improve the sound environment along a popular esplanade in Lyon, France, a 1 m high vegetated noise barrier was erected to protect against noise from an adjacent road. The barrier was made of a metallic structure, filled with a substrate on which 40 plants per square meter were grown on both sides. The effect of the barrier was evaluated by acoustic measurements conducted before and after the barrier was erected, as well as, by a questionnaire study in which pedestrians were asked to assess the sound environment both behind and at the side of the barrier. The barrier reduced the sound pressure level from about 67 to 62 dB (LAeq), at sitting height (1.2 m), 3.5 m from the roadside. Questionnaires responses (n = 349) from the same location showed that the barrier reduced road-traffic noise annoyance, and increased the overall quality of the sound environment by making it slightly calmer and slightly more pleasant. However, these effects were fairly small and the sound environment was still perceived as annoying by most of the respondents. Overall, the result thus suggested that the barrier made the sound environment better but not good. Further work will include detailed psychoacoustic analysis of the questionnaire data, as well as listening experiments using binaural recordings from the site.
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| 7. |
- Sun, Vivian Z., et al.
(author)
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Overview and Results From the Mars 2020 Perseverance Rover's First Science Campaign on the Jezero Crater Floor
- 2023
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In: Journal of Geophysical Research: Planets. - : John Wiley and Sons Inc. - 2169-9097 .- 2169-9100. ; 128:6
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Journal article (peer-reviewed)abstract
- The Mars 2020 Perseverance rover landed in Jezero crater on 18 February 2021. After a 100-sol period of commissioning and the Ingenuity Helicopter technology demonstration, Perseverance began its first science campaign to explore the enigmatic Jezero crater floor, whose igneous or sedimentary origins have been much debated in the scientific community. This paper describes the campaign plan developed to explore the crater floor's Máaz and Séítah formations and summarizes the results of the campaign between sols 100–379. By the end of the campaign, Perseverance had traversed more than 5 km, created seven abrasion patches, and sealed nine samples and a witness tube. Analysis of remote and proximity science observations show that the Máaz and Séítah formations are igneous in origin and composed of five and two geologic members, respectively. The Séítah formation represents the olivine-rich cumulate formed from differentiation of a slowly cooling melt or magma body, and the Máaz formation likely represents a separate series of lava flows emplaced after Séítah. The Máaz and Séítah rocks also preserve evidence of multiple episodes of aqueous alteration in secondary minerals like carbonate, Fe/Mg phyllosilicates, sulfates, and perchlorate, and surficial coatings. Post-emplacement processes tilted the rocks near the Máaz-Séítah contact and substantial erosion modified the crater floor rocks to their present-day expressions. Results from this crater floor campaign, including those obtained upon return of the collected samples, will help to build the geologic history of events that occurred in Jezero crater and provide time constraints on the formation of the Jezero delta.
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