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1 – 10 of over 1000Natalia Ewa Zalewska, Maja Mroczkowska-Szerszeń, Joerg Fritz and Maria Błęcka
This paper aims to characterize the mineral composition of Martian surfaces based on Thermal Emission Spectrometer (TES; Mars Global Surveyor) as measured in the infrared thermal…
Abstract
Purpose
This paper aims to characterize the mineral composition of Martian surfaces based on Thermal Emission Spectrometer (TES; Mars Global Surveyor) as measured in the infrared thermal range. It presents modeling and interpreting of TES spectral data from selected Martian regions from which the atmospheric influences had been removed using radiative transfer algorithm and deconvolution algorithm. The spectra from the dark area of Cimmeria Terra and the bright Isidis Planitia were developed in Philip Christensen’s and Joshua Bandfield’s publications, where these spectra were subjected to spectral deconvolution to estimate the mineral composition of the Martian surface. The results of the analyses of these spectra were used for the modeling of dusty and non-dusty surface of Mars. As an additional source, the mineral compositions of Polish basalts and mafic rocks were used for these surfaces as well as for modeling Martian meteorites Shergottites, Nakhlites and Chassignites. Finally, the spectra for the modeling of the Hellas region were obtained from the Planetary Fourier Spectrometer (PFS) – (Mars Express) and the mineralogical compositions of basalts from the southern part of Poland were used for this purpose. The Hellas region was modeled also using simulated Martian soil samples Phyllosilicatic Mars Regolith Simulant and Sulfatic Mars Regolith Simulant, showing as a result that the composition of this selected area has a high content of sulfates. Linear spectral combination was chosen as the best modeling method. The modeling was performed using PFSLook software written in the Space Research Centre of the Polish Academy of Sciences. Additional measurements were made with an infrared spectrometer in thermal infrared spectroscopy, for comparison with the measurements of PFS and TES. The research uses a kind of modeling that successfully matches mineralogical composition to the measured spectrum from the surface of Mars, which is the main goal of the publication. This method is used for areas where sample collection is not yet possible. The areas have been chosen based on public availability of the data.
Design/methodology/approach
The infrared spectra of the Martian surface were modeled by applying the linear combination of the spectra of selected minerals, which then are normalized against the measured surface area with previously separated atmosphere. The minerals for modeling are selected based on the expected composition of the Martian rocks, such as basalt. The software used for this purpose was PFSLook, a program written in C++ at the Space Research Centre of the Polish Academy of Sciences, which is based on adding the spectra of minerals in the relevant percentage, resulting in a final spectrum containing 100 per cent of the minerals.
Findings
The results of this work confirmed that there is a relationship between the modeled, altered and unaltered, basaltic surface and the measured spectrum from Martian instruments. Spectral deconvolution makes it possible to interpret the measured spectra from areas that are potentially difficult to explore or to choose interesting areas to explore on site. The method is described for mid-infrared because of software availability, but it can be successfully applied to shortwave spectra in near-infrared (NIR) band for data from the currently functioning Martian spectroscopes.
Originality/value
This work is the only one attempting modeling the spectra of the surface of Mars with a separated atmosphere and to determine the mineralogical composition.
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Minjuan Zhang, Ning Jing, Zhen Liu, Chunyang Li and Ning Zhang
An interferogram is produced by modulating the difference between the extraordinary refractive index and the ordinary refractive index for photoelastic crystals in…
Abstract
Purpose
An interferogram is produced by modulating the difference between the extraordinary refractive index and the ordinary refractive index for photoelastic crystals in photoelastic-modulated Fourier transform spectrometers (PEM-FTs). Due to the influence of the refractive index dispersion characteristics on the maximum optical path difference of the interferogram, it is necessary to study wavelength calibration methods.
Design/methodology/approach
A wavelength calibration method for PEM-FTs was proposed based on the modulation principle of the photoelastic-modulated interferometer and the relationship between the maximum optical path difference and the refractive index difference. A 632.8 nm narrow-pulse laser was used as a reference source to measure the maximum optical path difference () of the interferogram, and the parameter was used to calculate the discrete frequency points in the frequency domain. To account for the influence of refractive index dispersion on the maximum optical path difference, the refractive index curve for the photoelastic crystal was used to adjust the discrete frequency coordinates.
Findings
The error in the reconstructed spectral frequency coordinates clearly decreased. The maximum relative error was 2.5%. A good solar absorption spectrum was obtained with a PEM-FT experimental platform and the wavelength calibration method.
Originality/value
The interferogram is produced by adjusting the difference between extraordinary refractive index and ordinary refractive index for the photoelastic crystal in the PEM-FTs. Given the wavelength dependence on the refractive indices, in view of the modulation principle of the photoelastic modulated interferometer, the relationship between the maximum optical path difference and the refractive index difference, the variation law of the refractive index of the photoelastic crystal and the process of spectral reconstruction is presented in this paper.
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A NEW service, now available in this country from Wear‐Check International Inc. provides spectrometer analysis of used oil together with interpretation of results. This method of…
Abstract
A NEW service, now available in this country from Wear‐Check International Inc. provides spectrometer analysis of used oil together with interpretation of results. This method of oil analysis is not new and many large companies have their own direct reading spectrometer which is used for this, and other, purposes. The service now provided requires a 2 oz sample of the oil with relevant information about the equipment in which it has been used and the laboratory returns a report of the analysis of trace‐metals present with their interpretation of the causes of the results.
Harry Sminia, Anup Nair, Aylin Ates, Steve Paton and Marisa Smith
This chapter addresses the dynamics in inter-organizational relations. The authors probe the value networks so prevalent within contemporary manufacturing to put forward that…
Abstract
This chapter addresses the dynamics in inter-organizational relations. The authors probe the value networks so prevalent within contemporary manufacturing to put forward that their basic cooperation/competition duality manifests itself in practical terms as capability, appropriation, and governance paradoxes. The authors conducted a longitudinal ethnographic study aimed at capturing the process by which inter-organizational collaboration in manufacturing value networks is enacted. Our study finds that inter-organizational relations are “nested” in that a relationship plays out over an interpersonal network where the inter-organizational relationships are a framework for action, while simultaneously interpersonal interactions affect how the inter-organizational relationships take shape and evolve. Furthermore, we found that inter-organizational dynamics is essentially a stratified process. Solving particular and concrete problems at the surface level, with regard to specific collaboration issues between organizations, simultaneously shapes truces with regard to the underlying capability, appropriation, and governance paradoxes.
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