The SuperCam Instrument Suite on the Mars 2020 Rover: Science Objectives and Mast-Unit Description

On the NASA 2020 rover mission to Jezero crater, the remote determination of the texture, mineralogy and chemistry of rocks is essential to quickly and thoroughly characterize an area and to optimize the selection of samples for return to Earth. As part of the Perseverance payload, SuperCam is a suite of five techniques that provide critical and complementary observations via Laser-Induced Breakdown Spectroscopy (LIBS), Time-Resolved Raman and Luminescence (TRR/L), visible and near-infrared spectroscopy (VISIR), high-resolution color imaging (RMI), and acoustic recording (MIC). SuperCam operates at remote distances, primarily 2-7 m, while providing data at sub-mm to mm scales. We report on SuperCam's science objectives in the context of the Mars 2020 mission goals and ways the different techniques can address these questions. The instrument is made up of three separate subsystems: the Mast Unit is designed and built in France; the Body Unit is provided by the United States; the calibration target holder is contributed by Spain, and the targets themselves by the entire science team. This publication focuses on the design, development, and tests of the Mast Unit; companion papers describe the other units. The goal of this work is to provide an understanding of the technical choices made, the constraints that were imposed, and ultimately the validated performance of the flight model as it leaves Earth, and it will serve as the foundation for Mars operations and future processing of the data.In France was provided by the Centre National d'Etudes Spatiales (CNES). Human resources were provided in part by the Centre National de la Recherche Scientifique (CNRS) and universities. Funding was provided in the US by NASA's Mars Exploration Program. Some funding of data analyses at Los Alamos National Laboratory (LANL) was provided by laboratory-directed research and development funds

Inhibition efficiency of two bipyrazole derivatives on steel corrosion in hydrochloric acid media

244-253The inhibitor effect of two isomers namely 2-(1',5,5'-trimethyl-1H,1'H-3,3'-bipyrazol-1-yl)ethanol (1-TBE) and 2-(1',5,5'-trimethyl-1H,2'H-3,3'-bipyrazol-2-yl)ethanol (2-TBE) on the corrosion of mild steel in 1.0 M hydrochloric acid has been investigated at 308 K using weight loss measurements and electrochemical techniques (impedance spectroscopy and polarisation curves). Inhibition efficiency is dependent upon the pyrazole structure, with 1-TBE serving as a better inhibitor than 2-TBE and its inhibition efficiency increases with the increase of concentration of inhibitor to attain 93% in the presence of 10-3M. Polarisation curves indicate that 1-TBE and 2-TBE act essentially as cathodic inhibitors. Efficiency (E) percent values obtained by various methods are reasonably good in agreement. EIS measurements show an increase of the transfer resistance with the inhibitor concentration. The temperature effect on the corrosion behaviour of steel in 1.0 M HCl without and with the inhibitor at 10-3M is studied in the temperature range 308-333 K, Some thermodynamic parameters such as adsorption heat (H°), adsorption entropy (S°) and adsorption free energy (G°) have been calculated by employing thermodynamic equations. Kinetic parameters such as apparent activation energy and pre-exponential factor have also been calculated. Adsorption of 1-TBE on the mild steel surface in 1.0 M HCl follows the Langmuir isotherm model

Performance and computational studies of two soluble pyran derivatives as corrosion inhibitors for mild steel in HCl

The present study is aiming to explore the effect of 4-Hydroxy-6-methyl-3-(3-quinolin-8-yl-acryloyl)-pyran-2-one (HMQP) and 3-[3-(4-Dimethylamino-phenyl)-acryloyl]-4-hydroxy-6-methyl-pyran-2-one (DMPHP) on mild steel (MS) corrosion in acid solution (1 M HCl). The compound was tested at various concentrations (0.001–1 mM) and four temperatures (298, 308, 318, and 328 K) to determine the optimal concentration and temperature range for the best corrosion inhibiting effect. In evaluating the inhibition efficiency, weight loss measurement, potentiodynamic polarization measurement (PDP), electrochemical impedance spectroscopy, SEM/EDS and theoretical methods were used. The inhibition efficiencies increase with increase in concentration and decreases with temperature. The maximum inhibition efficiency was found 90% and 85.4% at 298 K in the presence of 1 mM of DMPHP and HMQP respectively. The experimental adsorption data obeyed the Langmuir isotherm model. The polarization parameters suggest that DMPHP and HMQP are mixed type inhibitors. The results of the EIS study suggest that these compounds inhibit corrosion by adsorption mechanism. A good correlation between theoretical and experimental results was obtained.Scopu

The inhibition of carbon steel corrosion in hydrochloric acid media using 2-[(5-methyl-isoxazol-3-yl)-methyl]-benzimidazole

Carbon steel corrosion inhibition in a hydrochloric acid solution by 2-[(5-methyl-isoxazol-3-yl)-methyl]-benzimidazole (MMB) has been studied by electrochemical techniques (PDP and EIS). Results showed that the inhibition efficiency increases with higher MMB concentration, and the maximum value of 86.6% was obtained at 10-3 M concentration. The prepared benzimidazole inhibitor showed higher inhibition efficiency upon raising the solution temperature from 303 to 333 K. Corrosion current density decreased from 660.9 µA cm-2 (blank) to 97.8 µA cm-2 (MMB) and charge transfer resistance increased from 20.2 Ω cm2 (blank) to 150.8 Ω cm2 (MMB). PDP studies showed that MMB is a mixed type inhibitor. The adsorption of this compound onto the carbon steel surface in a 1 M HCl solution followed the Langmuir adsorption isotherm, and the value of the standard free energy of adsorption ( ΔG° ads ) is associated to. © 2021, Sociedade Portuguesa de Electroquimica. All rights reserved

Experimental, DFT studies and molecular dynamic simulation on the corrosion inhibition of carbon steel in 1 M HCl by two newly synthesized 8-hydroxyquinoline derivatives

International audienceIn the present work, two new 8-hydroxyquinoline derivatives namely, 5-(((2-hydroxybenzylidene)amino)methyl) 8-hydroxyquinoline [HBMQ] and 5-(((4-chlorobenzylidene)amino)methyl) 8-hydroxyquinoline [CBMQ] were synthesized and investigated as corrosion inhibitors against the dissolution of carbon steel (C38 steel) in 1 M HCl. These compounds were obtained with high yield, and their structures were characterized by nuclear magnetic resonance spectroscopy (NMR) and elemental analysis. Gravimetric, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and surface morphology analyses utilizing scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) were used to quantify inhibitory performance. The adsorption process of inhibitory compounds was then demonstrated using quantum mechanics approaches such as Density Functional Theory (DFT) and Molecular Dynamic Simulation (MD). Based on EIS results, the investigated derivatives effectively inhibit the degradation of C38 steel over the entire concentration range with a maximum efficiency of 91.9% and 88.0% for [CBMQ] and [HBMQ], respectively, at 10−3 M. In addition, the PDP studies revealed that [HBMQ] and [CBMQ] compounds acted according to a mixed-type mechanism. Moreover, the adsorption mechanism follows the Langmuir isotherm model. The quantum theoretical study by DFT and MD simulation confirmed the experimental results