Transparency Feature Research Articles

Improved Delineation of Cardiac Pathology Using a Novel Three-Dimensional Echocardiographic Tissue Transparency Tool

Accurate visualization of cardiac valves and lesions by three-dimensional (3D) echocardiography is integral for optimal guidance of structural procedures and appropriate selection of closure devices. A new 3D rendering tool known as transillumination (TI), which integrates a virtual light source into the data set, was recently reported to effectively enhance depth perception and orifice definition. We hypothesized that adding the ability to adjust transparency to this tool would result in improved visualization and delineation of anatomy and pathology and improved localization of regurgitant jets compared with TI without transparency and standard 3D rendering. We prospectively studied 30 patients with a spectrum of structural heart disease who underwent 3D transesophageal imaging (EPIQ system, Philips) with standard acquisition and TI with and without the transparency feature. Six experienced cardiologists and sonographers were shown randomized images of all three display types in a blinded fashion. Each image was scored independently by all experts using a Likert scale from 1 to 5, while assessing each of the following aspects: (1) ability to recognize anatomy, (2) ability to identify pathology, including regurgitant jet origin, (3) depth perception, and (4) quality of border delineation. TI images with transparency were successfully obtained in all cases. All experts perceived an incremental value of the transparency mode, compared with TI without transparency and standard 3D rendering, in terms of ability to recognize anatomy (respective scores: 4.5±1.1 vs 4.1±1.1 vs 3.6±1.1, P<.05), ability to identify pathology (4.1±1.1 vs 3.9±1.2 vs 3.3±1, P<.05), depth perception (4.6±0.7 vs 4.1±0.8 vs 3.2±1.0, P<.05), and border delineation (4.6±0.8 vs 4.1±1.0 vs 3.1±1.1, P<.05). The addition of the transparency mode to TI rendering significantly improves the diagnostic and clinical utility of 3D echocardiography and has the potential to markedly enhance echocardiographic guidance of cardiac structural interventions.

Mid‐infrared reflectance spectroscopy of aubrite components

AbstractAubrites Peña Blanca Spring and Norton County were studied in the mid‐infrared reflectance as part of a database for the MERTIS (Mercury Radiometer and Thermal Infrared Spectrometer) instrument on the ESA/JAXA BepiColombo mission to Mercury. Spectra of bulk powder size fractions from Peña Blanca Spring show enstatite Reststrahlen bands (RB) at 9 µm, 9.3 µm, 9.9 µm, 10.4 µm, and 11.6 µm. The transparency feature (TF) is at 12.7 µm, the Christiansen feature (CF) at 8.1–8.4 µm. Micro‐FTIR of spots with enstatite composition in Norton County and Peña Blanca Spring shows four types: Types I and II are similar to the bulk powder spectra but vary in band shape and probably display axis orientation. Type III has characteristic strong RB at 9.2 µm, 10.4 µm, and 10.5 µm, and at 11.3 µm. Type IV is characterized by a strong RB at 10.8−11.1 µm. Types III and IV could show signs of incipient shock metamorphism. Bulk results of this study confirm earlier spectral studies of aubrites that indicate a high degree of homogeneity and probably make the results of this study representative for spectral studies of an aubrite parent body. Spectral types I and II occur in all mineralogical settings (mineral clasts, matrix, melt, fragments in melt vein), while spectral type III was only observed among the clasts, and type IV in the melt. Comparison with surface spectra of Mercury does not obtain a suitable fit, only type IV spectra from quenched impact glass show similarity, in particular the 11 µm feature. Results of this study will be available upon request or via the IRIS database (Münster) and the Berlin Emissivity Database (BED).

Inverted-ladder-type optical excitation of potassium Rydberg states with hot and cold ensembles

We present experimental results on the sub-Doppler Rydberg spectroscopy of potassium in a hot cell and cold atoms, performed with two counter-propagating laser beams of 405 nm and 980 nm in the inverted ladder-type system (4S1/2-5P3/2-nS1/2 and nD3/2;5/2). Such an inverted ladder-type scheme is predicted to be without sub-Doppler electromagnetically induced transparency (EIT) feature in a thermal ensemble under the weak-probe approximation. Instead, we utilized a strong probe field and successfully observed a transparency window with a width narrower than 50~MHz. Our all-order numerical simulation is in satisfactory agreement with the experimental results. This narrow linewidth allows us to measure the energy levels of the Rydberg levels from $n$=20-70 with improved accuracy. The deduced ionization energy agrees with the previous measurements. Furthermore, the two-photon Rydberg excitation scheme was applied to the cold ensembles to study the ground-state atoms population decrease in the MOT for various Rydberg states. Our experimental observations suggested two distinct regimes of the trap losses under different probe detuning conditions. While the far off-resonance case (\delta p>>0) can be described by the picture of dressed atom, the on-resonance case (\delta p~0) reveals more interesting results. The higher Rydberg states suffer larger trap loss. Besides, even with similar level energies, the excitation to nD states result in faster escape of the ground-state atom from trap than nearby nS states.

Space weathering by simulated micrometeorite bombardment on natural olivine and pyroxene: A coordinated IR and TEM study

We studied space-weathering effects caused by micrometeorite bombardment simulated by pulsed intense infrared laser, generating ∼15 mJ per pulse in high vacuum. For our investigation, we selected a natural olivine (San Carlos olivine (Fo91)) and a natural pyroxene (Bamble orthopyroxene (En87)) as important rock forming minerals of the Earth upper mantle as well as key planetary minerals. Irradiated areas of powdered pressed samples were examined by optical reflection spectroscopy in a broad optical and infrared wavelength range (visible-, near-, and mid-infrared) and transmission electron microscopy to identify changes due to micrometeorite impacts. The present study aims to investigate especially the effects of micrometeorite bombardment on reflectance spectra in the mid-IR in preparation for future space missions, as well as for the MERTIS experiment onboard the BepiColombo mission.For both irradiated samples, we found a reduction in albedo and in the reflectance of characteristic Reststrahlen bands and an increase of the transparency feature. VIS and NIR spectra of both minerals show the typical darkening and reddening as described for other space-weathered samples. TEM studies revealed that space-weathered layers in olivine and pyroxene differ in their respective thickness, ∼450 nm in olivine, 100-250 nm in pyroxene, as well as in developed “nanostratigraphy” of laser-ablated material, like nanophase iron (npFe).In conclusion, our spectral and structural findings were compared to samples in which space weathering was caused by different processes. A comparison with these data demonstrates that there is no difference in optical reflectance spectroscopy, but a significant difference in the microstructure of minerals due to the weathering source in space, as there are solar wind and solar flares cause other structural and chemical changes as the bombardment with micrometeorites.

Multifunctional Transparent Electromagnetic Surface Based on Solar Cell for Backscattering Reduction

Advanced electromagnetic (EM) surfaces, namely, metasurfaces, are designed for multifunctional purposes. A glass material with a chessboard configuration is exploited to realize nonabsorbing coating for backscattering reduction. Simultaneously, a solar cell is implemented above the metallic target for light energy harvesting using the transparency feature of the coat. Therefore, two separated aims are obtained in one structure using the plexiglass material and mono solar cell. Initially, the EM wave interactions with both materials are determined. Then, by the use of the wave interactions and scattering theory, two different surfaces are analytically investigated with the aim of transparent backscattering reduction cover. Next, an optimization algorithm is employed to achieve the minimum reflection from the adjacent surfaces. To validate the design performance, a prototype is manufactured. The proposed chessboard cover with plexiglass material is numerically and experimentally analyzed and compared together, having an acceptable agreement. The experimental results indicate a 75% bandwidth for backscattering reduction. In addition, the proposed structure can give promising opportunities to enhance the scattering properties with simultaneous power harvesting, which could generate critical advantages for real-world applications.

Electromagnetically induced transparency in inhomogeneously broadened solid media.

We study, theoretically and experimentally, electromagnetically induced transparency (EIT) in two different solid-state systems. Unlike many implementations in homogeneously broadened media, these systems exhibit inhomogeneous broadening of their optical and spin transitions typical of solid-state materials. We observe EIT lineshapes typical of atomic gases, including a crossover into the regime of Autler-Townes splitting, but with the substitution of the inhomogeneous widths for the homogeneous values. We obtain quantitative agreement between experiment and theory for the width of the transparency feature over a range of optical powers and inhomogeneous linewidths. We discuss regimes over which analytical and numerical treatments capture the behavior. As solid-state systems become increasingly important for scalable and integratable quantum optical and photonic devices, it is vital to understand the effects of the inhomogeneous broadening that is ubiquitous in these systems. The treatment presented here can be applied to a variety of systems, as exemplified by the common scaling of experimental results from two different systems.

Mid-infrared spectroscopy of planetary analogs: A database for planetary remote sensing

The MERTIS (MErcury Radiometer and Thermal Infrared Spectrometer) instrument onboard the ESA/JAXA BepiColombo mission will provide mid-infrared data, which will be crucial to characterize the surface mineralogy of Mercury. In order to interpret the results, we are creating a database of mid-infrared spectra. As part of a study of synthetic glasses which are to serve as analog materials for the interpretation of remote sensing and modeling data, we present mid-infrared data for analog materials of Mercury regolith, surface and mantle compositions. In addition, we provide data for similar analogs of Earth, Moon, Venus, and Mars rocks for a coherent picture.The analog samples have been first characterized by optical microscopy, Raman spectroscopy and EMPA. Powdered size fractions (0–25 μm, 25–63 μm, 63–125 μm, and 125–250 μm) were studied in reflectance in the mid-infrared range from 2.5 to 18 μm (550 to 2000 cm−1), additional micro-FTIR analyses were also obtained.Results for the size fractions of the surface and regolith analogs for Mercury show typical features for amorphous material with Christiansen Features (CF) at 8–8.1 μm, Reststrahlen Bands (RB) at 9.8–9.9 μm, and the Transparency Feature (TF) at 12 μm. The six bulk silicate Mercury analogs have varying CF positions from 8.1 to 9 μm, with RB crystalline features of various olivines dominating in most samples. Similarly, bulk silicate analogs of the other planetary bodies show glassy features for the surface analogs with CF from 7.9 μm (Earth Continental Crust) to 8.3 μm (Lunar Mare), strong RB from 9.5 μm (Earth Continental Crust) to 10.6 μm (Lunar Mare and Highlands). TF are usually very weak for the glassy analogs.Bulk silicate analogs for the other planetary bodies are again dominated by crystalline olivine features. Trends between SCFM (SiO2/(SiO2 + CaO + FeO + MgO)) index reflecting polymerization, CF and RB positions, and the SiO2 contents in previous studies are basically confirmed, but there is indication that several samples (Moon Mare and Highlands) do not follow the trend observed for low SiO2 samples and the RB position in earlier studies. Comparison with a ground based mid-IR spectrum of Mercury demonstrates general similarity in band positions with glassy Mercury surface and regolith material, and a chondrite based model of the planet. However, no mix so far can explain all spectral features.

Heterographic pun identification model based on multi-dimensional semantic relationships

Identifying heterographic puns is an important branch of humor research, which has gradually developed into a new research area. This paper presents a heterographic pun identification mechanism based on feature sets in four dimensions, namely, semantic transparency, semantic relevance, phonetic expansibility, and syntax feature sets. The semantic transparency feature sets consist of the lexical item statistics and the character length; the syntax feature sets include names, capitalization, tense, part of speech, and location. Nine features of the above four dimensions are added to a binary decision tree to generate a threshold and complete a pun identification with the help of K-means clustering. Using the corpus of the SemEval2017 Task 7, the proposed method achieves satisfactory results, and its F1 value outscores the top one out of all participating teams. The experiment outlined in this paper proves that the taxonomic approach of the binary decision tree algorithm based on four dimensions is effective in identifying heterographic puns. The phonetic expansibility and the syntax feature sets are particularly effective among all other dimensions, which is consistent with our presumption that the phonetic feature plays a bigger role in identifying heterographic puns.

MGS‐TES Spectra Suggest a Basaltic Component in the Regolith of Phobos

AbstractThe origins of the Martian moons Phobos and Deimos have been the subjects of considerable debate. Visible and near‐infrared spectra of these bodies are dark and nearly featureless, with red slopes of varying degrees. These spectra are generally consistent with those of carbonaceous asteroids, leading to the hypothesis that Phobos and Deimos are captured carbonaceous asteroids. The shapes and inclinations of the orbits of Phobos and Deimos present problems for the asteroid capture hypothesis. This had led researchers to suggest that Phobos and Deimos coaccreted with Mars or that they are the result of an impact with Mars or in the Mars vicinity. In this work, we reexamine Mars Global Surveyor Thermal Emission Spectrometer (MGS‐TES) data of Phobos and compare spectra of the Phobos surface to mid‐IR spectra of the ungrouped C2 meteorite Tagish Lake (a suggested analog for D‐class asteroids) and particulate basalt and phyllosilicate samples (mixed with carbon black to reduce their visible albedos) acquired in a simulated airless body environment. We find that Tagish Lake is a poor mid‐IR spectral analog to Phobos and that major spectral features in the Phobos spectrum are best matched by a silicate transparency feature similar to that found for finely particulate basalt. Other features in the spectrum are likely best explained by a phyllosilicate component. We suggest that these results indicate that at a portion of the Phobos surface regolith is derived from the Martian crust.

The outcomes and the mediating role of the functional triad: The users' perspective

AbstractB.J. Fogg's Functional Triad shows the manner in which computing technologies can persuade people by playing 3 different functional roles, namely, as tools, media, or social actors. However, the effects of user perceptions of these 3 functional roles are largely unknown. We advance Fogg's framework by developing a conceptual model to explain how a feature of a computing technology (ie, the trade‐off transparency feature of a recommendation agent [RA], which interactively demonstrates the trade‐offs among product attribute values) can result in certain outcomes by shaping the beliefs of individuals regarding the 3 functional roles. We examine the effects of the perceived Functional Triad on the following 3 outcomes: (1) persuading users to use an RA (intention to use), (2) persuading users to follow the advice of the RA (recommendation adherence), and (3) persuading users to recommend the RA to others (recommendation to friends). We conducted a laboratory experiment to manipulate 4 levels of trade‐off transparency, thereby creating an adequate amount of variations for the perceived Functional Triad. A total of 160 participants were recruited from a large university in North America. Although designers could control the technology design aspects, these designs may not accomplish the intended effects on users, who have their own perceptions. This study contributes to existing literature by simultaneously evaluating the 3 different outcomes of the Functional Triad from the perspective of users.

Chelyabinsk – a rock with many different (stony) faces: An infrared study

In order to provide spectral ground truth data for remote sensing applications, we have measured mid-infrared spectra (2–18 µm) of three typical, well-defined lithologies from the Chelyabinsk meteorite that fell on February 15, 2013, near the city of Chelyabinsk, southern Urals, Russia. These lithologies are classified as (a) moderately shocked, light lithology, (b) shock-darkened lithology, and (c) impact melt lithology. Analyses were made from bulk material in four size fractions (0–25 µm, 25–63 µm, 63–125 µm, and 125–250 µm), and from additional thin sections.Characteristic infrared features in the powdered bulk material of the moderately shocked, light lithology, dominated by olivine, pyroxene and feldspathic glass, are a Christiansen feature (CF) between 8.5 and 8.8 µm; a transparency feature (TF) in the finest size fraction at ∼13 µm, and strong reststrahlen bands (RB) at ∼9.1 µm, 9.5 µm, 10.3 µm, 10.8 µm, 11.2–11.3 µm, 12 µm, and between 16 and 17 µm. The ranges of spectral features for the micro-FTIR spots show a wider range than those obtained in diffuse reflectance, but are generally similar.With increasing influence of impact shock from ‘pristine’ LL5 (or LL6) material (which have a low or moderate degree of shock) to the shock-darkened lithology and the impact melt lithology as endmembers, we observe the fading/disappearing of spectral features. Most prominent is the loss of a ‘twin peak’ feature between 10.8 and 11.3 µm, which turns into a single peak. In addition, in the ‘pure’ impact melt “endmember lithology” features at ∼9.6 µm and ∼9.1 µm are also lost. These losses are most likely correlated with decreasing amounts of crystal structure as the degree of shock melting increases. These changes could connect mid-infrared features with stages for shock metamorphism (Stöffler et al., 1991): Changes up to shock stage S4 would be minor, the shock darkened lithology could represent S5 and the impact melt lithology S6 and higher.Similarities of the Chelyabinsk spectra to those of other LL chondrites indicate that the findings of this study could be related to this group of meteorites in general.

Spatial Locality Aware Disk Scheduling in Virtualized Environment

Exploiting spatial locality, a key technique for improving disk I/O utilization and performance, faces additional challenges in the virtualized cloud because of the transparency feature of virtualization. This paper contributes a novel disk I/O scheduling framework, named Pregather, to improve disk I/O efficiency through exposure and exploitation of the special spatial locality in the virtualized environment, thereby improving the performance of disk-intensive applications without harming the transparency feature of virtualization. The key idea behind Pregather is to implement an intelligent model to predict the access regularity of spatial locality for each VM. Moreover, Pregather embraces an adaptive time slice allocation scheme to further reduce the resource contention and ensure fairness among VMs. We implement the Pregather disk scheduling framework and perform extensive experiments that involve multiple simultaneous applications of both synthetic benchmarks and MapReduce applications on Xen-based platforms. Our experiments demonstrate the accuracy of our prediction model and indicate that Pregather results in the high disk spatial locality and a significant improvement in disk throughput and application performance.

Realization and Modeling of Metamaterials Made of rf Superconducting Quantum-Interference Devices

We have prepared meta-atoms based on radio frequency superconducting quantum interference devices (RF SQUIDs) and examined their tunability with dc magnetic field, rf current, and temperature. RF SQUIDs are superconducting split ring resonators in which the usual capacitance is supplemented with a Josephson junction, which introduces strong nonlinearity in the rf properties. We find excellent agreement between the data and a model which regards the Josephson junction as the resistively and capacitively-shunted junction. A magnetic field tunability of 80 THz/Gauss at 12 GHz is observed, a total tunability of 56$%$ is achieved, and a unique electromagnetically-induced transparency feature at intermediate excitation powers is demonstrated for the first time. An RF SQUID metamaterial is shown to have qualitatively the same behavior as a single RF SQUID with regards to DC flux and temperature tuning.

Thermal infrared spectra of experimentally shocked andesine anorthosite

Andesine-rich (An36–46) anorthosite rocks experimentally shocked to high pressures (16–57GPa) exhibit changes in spectral features with increasing pressure in laboratory thermal infrared emission spectra (250–1400cm−1). These results are similar to previous studies of shocked bytownite- and albite-rich rocks, albeit with differences in absorption band centers characteristic of mineralogy and composition. Typical spectral absorptions result from Si–O antisymmetric stretch motions of the silica tetrahedral (1000–1250cm−1) and weaker absorptions due to Si–O–Si octahedral bending vibrations (350–700cm−1). Many of these features persist to higher pressures in the andesine spectra compared to similar features in measurements of shocked bytownite. This is consistent with previous thermal infrared absorption studies of shocked feldspars and likely is related to differences in density, hardness, and Al content. A transparency feature at ∼832cm−1 observed in powdered andesine spectra also degrades with increasing pressure, intermediate between the ∼828cm−1 and ∼855cm−1 transparency features in spectra of powders of shocked bytownite and albitite, respectively. These data can be incorporated into thermal infrared spectral analyses of cratered planetary surfaces (or laboratory spectra of shocked samples) to help constrain the occurrence and degree of shock in plagioclase feldspars.

Deposition of PEDOT: PSS Nanoparticles as a Conductive Microlayer Anode in OLEDs Device by Desktop Inkjet Printer

A simple microfabrication technique for delivering macromolecules and patterning microelectrode arrays using desktop inkjet printer was described. Aqueous solution of nanoparticle of poly (3,4-ethylenedioxythiophene) (PEDOT) doped with polystyrene sulfonic acid (PSS) was prepared while its particle size, the surface tension, and the viscosity of the solution were adjusted to be suitable for deposition on a flexible cellulose nanocomposite substrate via inkjet printer. The statistical average of PEDOT: PSS particle size of 100 nm was observed. The microthickness, surface morphology, and electrical conductivity of the printed substrate were then characterized by profilometer, atomic force microscope (AFM), and four-point probe electrical measurement, respectively. The inkjet deposition of PEDOT: PSS was successfully carried out, whilst retained its transparency feature. Highly smooth surface (roughness ~23–44 nm) was achieved.

Effect of buffer gas on an electromagnetically induced transparency in a ladder system using thermal rubidium vapor

We report on the first observation of electromagnetically induced transparency (EIT) in a ladder system in the presence of a buffer gas. In particular we study the 5S1/2 - 5P3/2 - 5D5/2 transition in thermal rubidium vapor with a neon buffer gas at a pressure of 6 Torr. In contrast to the line narrowing effect of buffer gas on {\Lambda}-systems we show that the presence of the buffer gas leads to an additional broadening of (32 +/- 5) MHz, which suggests a cross section for Rb(5D5/2)-Ne of {\sigma} = (7 +/- 1) x 10-19 m2. However, in the limit where the coupling Rabi frequency is larger than k the collisional dephasing a strong transparency feature can still be observed.

Spectral properties of simulated impact glasses produced from martian soil analogue JSC Mars-1

To simulate the formation of impact glasses on Mars, an analogue of martian bright soil (altered volcanic soil JSC Mars-1) was melted at relevant oxygen fugacities using a pulsed laser and a resistance furnace. Reduction of Fe3+ to Fe2+ and in some cases formation of nanophase Fe0 in the glasses were documented by Mössbauer spectroscopy and TEM studies. Reflectance spectra for several size fractions of the JSC Mars-1 sample and the glasses were acquired between 0.3 and 25 μm. The glasses produced from the JSC Mars-1 soil show significant spectral variability depending on the method of production and the cooling rate. In general, they are dark and less red in the visible compared to the original JSC Mars-1 soil. Their spectra do not have absorption bands due to bound water and structural OH, have positive spectral slopes in the near-infrared range, and show two broad bands centered near 1.05 and 1.9 μm, typical of glasses rich in ferrous iron. The latter bands and low albedo partly mimic the spectral properties of martian dark regions, and may easily be confused with mafic materials containing olivine and low-Ca pyroxene. Due to their disordered structures and vesicular textures, the glasses show relatively weak absorption features from the visible to the thermal infrared. These weak absorption bands may be masked by the stronger bands of mafic minerals. Positive near-infrared spectral slopes typical of fresh iron-bearing impact or volcanic glasses may be masked either by oxide/dust coatings or by aerosols in the Mars' atmosphere. As a result, impact glasses may be present on the surface of Mars in significant quantities that have been either misidentified as other phases or masked by phases with stronger infrared features. Spectrometers with sufficient spatial resolution and wavelength coverage may detect impact glasses at certain locations, e.g., in the vicinity of fresh impact craters. Such dark materials are usually interpreted as accumulations of mafic volcanic sand, but the possibility of an impact melt origin of such materials also should be considered. In addition, our data suggest that high contents of feldspars or zeolites are not necessary to produce the transparency feature at 12.1 μm typical of martian dust spectra.

Electromagnetically induced transparency induced by a 100% amplitude-modulated coupling field

We present a study of electromagnetically induced transparency (EIT) under the excitation of a 100% amplitude-modulated (AM) coupling field. The EIT feature is associated with a Λ type three-level configuration where a coupling and probe field couples two separate optical transitions and it is well-known that the spectrum of the swept probe field gives a simple single transparency feature induced by the single mode coupling field. It is shown that when a 100% AM coupling field is applied, there is an EIT doublet and the separation of the EIT doublet can be controlled by the modulation frequency of the coupling field. Our result implies a new way of manipulating EIT resonance and opening more than one EIT windows.

Visible, near‐infrared, and middle infrared spectroscopy of altered basaltic tephras: Spectral signatures of phyllosilicates, sulfates, and other aqueous alteration products with application to the mineralogy of the Columbia Hills of Gusev Crater, Mars

We studied visible to near‐infrared (VNIR, 0.35–2.5 μm) and middle infrared (MIR, 1800–250 cm−1, also called thermal infrared and vibrational) spectra of basaltic tephras from Mauna Kea volcano that were altered under ambient, hydrothermal (hydrolytic and acid sulfate), and dry heat conditions. Although models of MIR spectra of altered tephras generally produce fits whose quality is reduced compared to deconvolutions of primary lithologies, they successfully identify major alteration phases (cristobalite, oxide, phyllosilicate, and sulfate) except in palagonites. MIR spectra of the &lt;45 μm fraction of all altered tephra samples exhibit an H2O peak at ∼1640 cm−1, but it cannot be used as an indicator of H2O content. This feature is present with band strengths &gt;1% in spectra of the 500–1000 μm fraction only if phyllosilicates are present. Although Mauna Kea palagonitic tephra is considered a VNIR analog to Martian dust, comparison of MIR altered tephra spectra (&lt;45 μm fraction) to dust spectra retrieved from Mars Global Surveyor and Mars Exploration Rover instruments do not provide good spectral matches. The best MIR match is a tephra that has a strong plagioclase feldspar transparency feature and was altered under dry, high‐temperature, oxidizing conditions. This sample is not a VNIR analog and is not a process analog, but it emphasizes the mineralogical importance of plagioclase feldspar in Martian dust. No single tephra is a good spectral analog across the VNIR and MIR. We found no evidence for substantial sulfates or phyllosilicates in Mini‐Thermal Emission Spectrometer (Mini‐TES) spectra from Gusev Crater.

The Mercury Radiometer and Thermal Infrared Spectrometer (MERTIS) for the BepiColombo mission

Scheduled for launch on board the BepiColombo Mercury Planetary Orbiter (MPO) in 2014, the Mercury Radiometer and Thermal Infrared Spectrometer (MERTIS) is an innovative instrument for studying the surface composition and mineralogy of planet Mercury. MERTIS combines an uncooled grating push broom IR-spectrometer (TIS) with a radiometer (TIR), which will operate in the wavelength region of 7–14 and 7–40 μm, respectively. The spatial resolution of the MERTIS observations will be about 500 m globally and better than 500 m for approximately 5–10% of the surface. The thermal infrared range offers unique diagnostic capabilities to study the surface composition of Mercury. In particular, feldspars can easily be detected and characterized, because they show several diagnostic spectral signatures in the 7–14 μm range: the Christiansen feature, reststrahlen bands, and the transparency feature. In addition, MERTIS will allow the identification and mapping of elemental sulfur, pyroxenes, olivines, and other complex minerals. The scientific objectives of MERTIS include: (1) characterization of Mercury's surface composition, (2) identification of rock-forming minerals, (3) mapping of the surface mineralogy, and (4) study of surface temperature variations and the thermal inertia. In preparation for the MERTIS data interpretation, we are performing spectral measurements of appropriate analogue materials in the Planetary Emissivity Laboratory (PEL) and are building a spectral library (Berlin Emissivity Database (BED)) of these materials for a variety of grain sizes.