scholarly journals Polarization lidar: an extended three-signal calibration approach

2019 ◽  
Vol 12 (2) ◽  
pp. 1077-1093 ◽  
Author(s):  
Cristofer Jimenez ◽  
Albert Ansmann ◽  
Ronny Engelmann ◽  
Moritz Haarig ◽  
Jörg Schmidt ◽  
...  
Keyword(s):  
Polarization Plane ◽  
Laser Pulses ◽  
Experimental Conditions ◽  
New Formalism ◽  
Long Term Stability ◽  
Receiver Unit ◽  
Water Cloud ◽  
Elliptically Polarized

Abstract. We present a new formalism to calibrate a three-signal polarization lidar and to measure highly accurate height profiles of the volume linear depolarization ratios under realistic experimental conditions. The methodology considers elliptically polarized laser light, angular misalignment of the receiver unit with respect to the main polarization plane of the laser pulses, and cross talk among the receiver channels. A case study of a liquid-water cloud observation demonstrates the potential of the new technique. Long-term observations of the calibration parameters corroborate the robustness of the method and the long-term stability of the three-signal polarization lidar. A comparison with a second polarization lidar shows excellent agreement regarding the derived volume linear polarization ratios in different scenarios: a biomass burning smoke event throughout the troposphere and the lower stratosphere up to 16 km in height, a dust case, and also a cirrus cloud case.

scholarly journals Polarization lidar: An extended three-signal calibration approach

2018 ◽  
Author(s):  
Cristofer Jimenez ◽  
Albert Ansmann ◽  
Moritz Haarig ◽  
Ronny Engelmann ◽  
Jörg Schmidt ◽  
...  
Keyword(s):  
Polarization Plane ◽  
Laser Pulses ◽  
Experimental Conditions ◽  
New Formalism ◽  
Long Term Stability ◽  
Receiver Unit ◽  
Water Cloud ◽  
Elliptically Polarized

Abstract. We present a new formalism to calibrate a three-signal polarization lidar and to measure highly accurate height profiles of the volume linear depolarization ratios under realistic experimental conditions. The methodology considers elliptically polarized laser light, angular misalignment of the receiver unit with respect to the main polarization plane of the laser pulses, and cross-talk between the receiver channels. A case study of a liquid-water cloud observation demonstrates the potential of the new technique. Long-term observations of the calibration parameters corroborate the robustness of the method and the long-term stability of the three-signal polarization lidar. A comparison with another polarization lidar shows excellent agreement regarding the derived volume linear polarization ratio of biomass burning smoke throughout the troposphere and the lower stratosphere up to 16 km height.

scholarly journals A Compact Muon Tracker for Dynamic Tomography of Density Based on a Thin Time Projection Chamber with Micromegas Readout

Particles ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 333-342
Author(s):  
Ignacio Lázaro Roche
Keyword(s):  
Time Projection Chamber ◽  
Wide Field ◽  
Track Reconstruction ◽  
Long Term Stability ◽  
Societal Issues ◽  
Primary Signal ◽  
And Performance ◽  
Time Projection

Tomography based on cosmic muon absorption is a rising technique because of its versatility and its consolidation as a geophysics tool over the past decade. It allows us to address major societal issues such as long-term stability of natural and man-made large infrastructures or sustainable underwater management. Traditionally, muon trackers consist of hodoscopes or multilayer detectors. For applications with challenging available volumes or the wide field of view required, a thin time projection chamber (TPC) associated with a Micromegas readout plane can provide a good tradeoff between compactness and performance. This paper details the design of such a TPC aiming at maximizing primary signal and minimizing track reconstruction artifacts. The results of the measurements performed during a case study addressing the aforementioned applications are discussed. The current works lines and perspectives of the project are also presented.

Photodissolution of iron oxides. IV. A comparative study on the photodissolution of hematite, magnetite, and maghemite in EDTA media

1992 ◽  
Vol 70 (9) ◽  
pp. 2502-2510 ◽  
Author(s):  
Marta I. Litter ◽  
Miguel A. Blesa
Keyword(s):  
Reaction Rates ◽  
Thermal Reaction ◽  
Oxidation Products ◽  
Experimental Conditions ◽  
Spinel Type ◽  
Long Term Stability ◽  
Initiation Step ◽  
Edta Complexes ◽  
Photooxidation Reaction

The thermal and 254-nm photochemical dissolution reactions of magnetite (Fe3O4), maghemite (γ-Fe2O3), and hematite (α-Fe2O3) suspended in EDTA aqueous solutions were compared. γ-Fe2O3 and Fe3O4 are thermally and photochemically more reactive than α-Fe2O3. Both thermal and photochemical dissolution reactions are governed by an initiation step, which involves the production of FeIIaq, and a subsequent thermal reaction of these ions with the solid, to produce FeIIIaq. The initiation step under UV irradiation involves the photoreduction of surface >FeIII – EDTA complexes to yield FeIIaq and the photooxidation of adsorbed EDTA to yield CH2O and other oxidation products. After FeIII – EDTA complexes build up in solution through the following step, homogeneous photolysis is the main source of FeII and CH2O. Oxides with spinel type structure are characterized by faster rates in the two processes, and O2 may inhibit the dissolution processes by changing the stoichiometry of the initiation step to that of the autooxidation of EDTA. The relative importance of autooxidation and photodissolution depends on the nature of the oxide and the experimental conditions. Photooxidation reaction rates parallel those of the photodissolution initiation steps, and long-term stability towards photocorrosion (dissolution) implies low photocatalytic activity for the oxidation of EDTA. The set of differential equations describing all the reaction rates is discussed and applied to the different cases.

Advances in Research, Development, and Testing of Single Cells at Forschungszentrum Jülich

2009 ◽  
Vol 6 (2) ◽  
Author(s):  
V. A. C. Haanappel ◽  
N. Jordan ◽  
A. Mai ◽  
J. Mertens ◽  
J. M. Serra ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Research And Development ◽  
Solid Oxide Fuel Cells ◽  
Power Output ◽  
Single Cells ◽  
Experimental Conditions ◽  
Microstructural Parameters ◽  
Long Term Stability ◽  
Measurement Results

This paper presents an overview of the main advances in solid oxide fuel cells (SOFCs) research and development (R&D), measurement standardization, and quality assurance in SOFC testing at the Forschungszentrum Jülich. These activities have resulted in both a significant improvement of the electrochemical performance and a better understanding of the electrochemical behavior of SOFCs. Research and development of SOFCs was mainly focused on two types of anode-supported cells, namely, those employing either La0.65Sr0.3MnO3 (LSM) or La0.58Sr0.4Co0.2Fe0.8O3−δ (LSCF) cathode materials. In both cases the optimization of processing and microstructural parameters resulted in satisfactory power output and long-term stability at reduced operation temperatures. Standardization and quality assurance in SOFC testing was also addressed with the goal of producing consistent and reliable tests and measurement results. At present, under optimized experimental conditions, SOFCs with LSM or LSCF cathodes can deliver a power output of about 1.0 W/cm2 and 1.9 W/cm2 at 800°C (700 mV), respectively.

Electrochemical nanogravimetric studies of adsorption, deposition, and dissolution processes occurring at platinum electrodes in acid media

2010 ◽  
Vol 83 (2) ◽  
pp. 269-279 ◽  
Author(s):  
György Inzelt ◽  
Balázs B. Berkes ◽  
Ákos Kriston
Keyword(s):  
Proton Exchange ◽  
Platinum Electrodes ◽  
Experimental Conditions ◽  
Acid Media ◽  
Surface Mass ◽  
Long Term Stability ◽  
Platinized Platinum ◽  
Electrochemical Double Layer ◽  
Electrochemical Quartz Crystal Nanobalance

Polycrystalline smooth and platinized platinum electrodes have been extensively employed in electrochemistry. It is of utmost importance to gain a deeper insight into the processes occurring during their electrochemical transformations. Piezoelectric nanogravimetry by using electrochemical quartz crystal nanobalance (EQCN) is one of the most powerful tools for obtaining information on the events occurring at the electrode surface. This method has been exploited to monitor the surface mass changes as a function of the electrode potential varying the experimental conditions (time scale, solution composition, temperature), which allows one to draw conclusions in respect of the formation and removal of adsorbed and deposited species as well as changes in the electrochemical double layer. Furthermore, platinum dissolution processes, which are of importance (e.g., regarding the long-term stability of proton exchange fuel cells), are also discussed.

Cluster-based comparison of the peptide mass fingerprint obtained by MALDI-TOF mass spectrometry. A case study: long-term stability of rituximab

The Analyst ◽  
2015 ◽  
Vol 140 (5) ◽  
pp. 1717-1730 ◽  
Author(s):  
Pablo J. Villacorta ◽  
Antonio Salmerón-García ◽  
David A. Pelta ◽  
José Cabeza ◽  
Antonio Lario ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Monoclonal Antibodies ◽  
Peptide Mass Fingerprint ◽  
Maldi Tof Ms ◽  
Long Term Stability ◽  
Maldi Tof ◽  
Peptide Mass ◽  
Tof Ms

A cluster-based comparison algorithm applied to the MALDI-TOF-MS peptide mass fingerprint allows for tracking major changes in protein such as monoclonal antibodies.

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