John Michael Morookian

Microscopy capabilities of the Microscopy, Electrochemistry, and Conductivity Analyzer

The Phoenix microscopy station, designed for the study of Martian dust and soil,consists of a sample delivery system, an optical microscope, and an atomic force microscope. The combination of microscopies facilitates the study of features from the millimeter to nanometer scale. Light-emitting diode illumination allows for full color optical imaging of the samples as well as imaging of ultraviolet-induced visible fluorescence. The atomic force microscope uses an array of silicon tips and can operate in both static and dynamic mode.

Mineralogy, provenance, and diagenesis of a potassic basaltic sandstone on Mars: CheMin X-ray diffraction of the Windjana sample (Kimberley area, Gale Crater)

Abstract The Windjana drill sample, a sandstone of the Dillinger member (Kimberley formation, Gale Crater, Mars), was analyzed by CheMin X‐ray diffraction (XRD) in the MSL Curiosity rover. From Rietveld refinements of its XRD pattern, Windjana contains the following: sanidine (21% weight, ~Or95); augite (20%); magnetite (12%); pigeonite; olivine; plagioclase; amorphous and smectitic material (~25%); and percent levels of others including ilmenite, fluorapatite, and bassanite. From mass balance on the Alpha Proton X‐ray Spectrometer (APXS) chemical analysis, the amorphous material is Fe rich with nearly no other cations—like ferrihydrite. The Windjana sample shows little alteration and was likely cemented by its magnetite and ferrihydrite. From ChemCam Laser‐Induced Breakdown Spectrometer (LIBS) chemical analyses, Windjana is representative of the Dillinger and Mount Remarkable members of the Kimberley formation. LIBS data suggest that the Kimberley sediments include at least three chemical components. The most K‐rich targets have 5.6% K2O, ~1.8 times that of Windjana, implying a sediment component with >40% sanidine, e.g., a trachyte. A second component is rich in mafic minerals, with little feldspar (like a shergottite). A third component is richer in plagioclase and in Na2O, and is likely to be basaltic. The K‐rich sediment component is consistent with APXS and ChemCam observations of K‐rich rocks elsewhere in Gale Crater. The source of this sediment component was likely volcanic. The presence of sediment from many igneous sources, in concert with Curiositys identifications of other igneous materials (e.g., mugearite), implies that the northern rim of Gale Crater exposes a diverse igneous complex, at least as diverse as that found in similar‐age terranes on Earth.

Microscopy analysis of soils at the Phoenix landing site, Mars: Classification of soil particles and description of their optical and magnetic properties

The optical microscope onboard the Phoenix spacecraft has returned color images (4 ?m pixel?1) of soils that were delivered to and held on various substrates. A preliminary taxonomy of Phoenix soil particles, based on color, size, and shape, identifies the following particle types [generic names in brackets]: (1) reddish fines, mostly unresolved, that are spectrally similar to (though slightly darker than) global airborne dust [red fines], (2) silt? to sand?sized brownish grains [brown sand], (3) silt? to sand?sized black grains [black sand], and (4) small amounts of whitish fines, possibly salts [white fines]. Most particles have a saturation magnetization in the range 0.5?2 Am2 kg?1 as inferred from their interaction with magnetic substrates. The particle size distribution has two distinct peaks below 10 ?m (fines) and in the range 20–100 ?m (grains), respectively, and is different from that of ripple soils in Gusev crater. In particular medium to large sand grains appear to be absent in Phoenix soils. Most sand grains have subrounded shape with variable texture. A fractured grain (observed on sol 112) reveals evidence of micrometer?sized crystal facets. The brown sand category displays a large diversity in color including shiny, almost colorless particles. Potential source regions for these grains may be the Tharsis volcanoes or Heimdal crater (20 km east of the landing site). The black grains are suggested to belong to a more widespread population of particles with mafic mineralogy. The absence of black/brown composite grains is consistent with different formation pathways and source regions for each grain type.

Optical microactuation in piezoceramics

Optically/electrically operable flexible film microactuators that can offer up to two orders high efficiency of photonic to mechanical conversion compared to ceramic actuators are conceptualized. A polarized ceramic wafer of non- centrosymmetric perovskite ferroelectric ABO3 compounds, such as lead lanthanum zirconate titanate (PLZT), when exposed to an illumination (approximately 350 to 400 nm wavelength) close to the bandgap energy, can generate a large photovoltage (approximately 1.0 kV/mm) across its length, and by the inverse piezoelectric effect cause the piezoceramic wafer to deflect in the direction away from the illumination. The optical actuation effect in piezoceramic wafers is investigated as a function of thickness, composition, and surface roughness. Such flexible microactuators would enable a new generation of micro- electro-mechanical and micro-opto-mechanical systems where the actuation will not be restricted by the clamping effect due to the rigid substrate as in the current silicon based micromachined structures. To deposit the piezoceramic film directly onto a flexible substrate, the substrate must have high temperature stability, high strength (Youngs Modulus approximately 4.9 X 1010 N/m2), a close match of thermal coefficients of expansion with the piezoceramic film, and a tailorable crystal orientation in order to provide a desired template for growth of oriented PLZT. This paper also presents a comparison of a variety of flexible substrate films and fibers and our recent results on polybenzoxazole (PBO), a polymeric candidate for a flexible high temperature substrate. Variation of the properties of PBO as a function of temperature are also presented.

The first X-ray diffraction measurements on Mars

The X-ray diffraction/X-ray fluorescence instrument CheMin on the Curiosity rover is a shoebox-sized device using transmission geometry and an energy-discriminating CCD detector. The instrument has returned the first X-ray diffraction data for soil and drilled samples from Mars outcrops, revealing a suite of primary basaltic minerals, amorphous components and varied hydrous alteration products including phyllosilicates.

Measurement of Amphotericin B concentration by Resonant Raman Spectroscopy – a novel technique that may be useful for non-invasive monitoring

We wished to determine whether Resonant Raman Spectroscopy (RRS) could be used to measure Amphotericin B (AmB) at therapeutic and subtherapeutic concentrations in a model system mimicking the anterior chamber of the eye. The goal was to develop a technique for non-invasive measurement of AmB levels in the aqueous humor (AH) of the eye. A krypton-ion laser source (406.7 nm) was used for excitation and Resonant Raman Spectra were captured with a confocal system in an anterior chamber (AC) model. These spectra were used to develop a correlation curve for prediction of AmB levels. Subsequently, one rabbit was evaluated with this system after 5 days of intravenous AmB administration (1 mg/kg/day) and AmB concentrations measured by RRS were compared to those measured by high-performance liquid chromatography (HPLC). AmB exhibited a unique spectral peak at 1557 cm(-1). Integrated area of this peak linearly correlated with AmB concentration in our model AC. When integrated peak area from multiple in vivo measurements in one animal at steady-state was plotted on this correlation curve, we were able to predict AmB levels. These closely approximated those measured by HPLC. These measurements were not significantly affected by photobleaching or depth profile at acquisition. RRS at 406.7 nm is a method that may be useful for non-invasive monitoring of intraocular AmB levels. This instrument can help physicians decide when repeat, invasive delivery of this drug is warranted based on measurement of actual drug levels in the AH. Also, there is the potential to measure the ocular concentrations of other pharmaceutical agents with similar instruments.

Relationships between unit-cell parameters and composition for rock-forming minerals on Earth, Mars, and other extraterrestrial bodies

Abstract Mathematical relationships between unit-cell parameters and chemical composition were developed for selected mineral phases observed with the CheMin X-ray diffractometer onboard the Curiosity rover in Gale crater. This study presents algorithms for estimating the chemical composition of phases based solely on X-ray diffraction data. The mineral systems include plagioclase, alkali feldspar, Mg-Fe-Ca C2/c clinopyroxene, Mg-Fe-Ca P21/c clinopyroxene, Mg-Fe-Ca orthopyroxene, Mg-Fe olivine, magnetite, and other selected spinel oxides, and alunite-jarosite. These methods assume compositions of Na-Ca for plagioclase, K-Na for alkali feldspar, Mg-Fe-Ca for pyroxene, and Mg-Fe for olivine; however, some other minor elements may occur and their impact on measured unit-cell parameters is discussed. These crystal-chemical algorithms can be applied to material of any origin, whether that origin is Earth, Mars, an extraterrestrial body, or a laboratory.

Clay mineral diversity and abundance in sedimentary rocks of Gale crater, Mars

Clay minerals found in Gale crater, Mars, record surficial chemical weathering and changing conditions in an ancient lake. Clay minerals provide indicators of the evolution of aqueous conditions and possible habitats for life on ancient Mars. Analyses by the Mars Science Laboratory rover Curiosity show that ~3.5–billion year (Ga) fluvio-lacustrine mudstones in Gale crater contain up to ~28 weight % (wt %) clay minerals. We demonstrate that the species of clay minerals deduced from x-ray diffraction and evolved gas analysis show a strong paleoenvironmental dependency. While perennial lake mudstones are characterized by Fe-saponite, we find that stratigraphic intervals associated with episodic lake drying contain Al-rich, Fe3+-bearing dioctahedral smectite, with minor (3 wt %) quantities of ferripyrophyllite, interpreted as wind-blown detritus, found in candidate aeolian deposits. Our results suggest that dioctahedral smectite formed via near-surface chemical weathering driven by fluctuations in lake level and atmospheric infiltration, a process leading to the redistribution of nutrients and potentially influencing the cycling of gases that help regulate climate.

Advances in multi-channel optical multi-gbytes/sec bit-parallel WDM single fiber link

For ultra-high-speed single media parallel interconnects, an all optical single fiber WDM format of transmitting parallel bits rather than a fiber ribbon format where parallel bits are sent through corresponding parallel fibers in a ribbon format, can be the media of choice. Here, we shall discuss the realization of a multi-km x gbytes/sec bit-parallel WDM (BP-WDM) single fiber link. The distance-speed product of this single fiber link is more than several orders of magnitude higher than that of a fiber ribbon link. The design of a 12 bit-parallel channels WDM system operating at 1 Gbit/sec per channel rate through a single fiber will first be presented. Experimental results for a two channel system operating at that rate are given. Further improvement of distance-speed product for the BP-WDM link can be obtained with JPLs newly developed 20 Gbits/sec per channel laser diode array transmitter. Also, new computer simulation results on how a large amplitude co-propagating pulse may induce pulse compression on all the co-propagating data pulses, thereby improving the shaping of these pulses for a WDM system, will be presented and discussed. The existence of WDM solitons is also shown.

WDM component requirements for bit-parallel fiber optic computer networks

The device specifications for an all optical bit-parallel WDM single fiber link for the cluster computer network community are intended for dissemination to the opto- electronic device research community to stimulate synergy between the two, ultimately leading to early availability of new devices to the computer network researchers. It is also hoped that early adoption of these devices by the research community will promote limited production of these devices by industry. Background information on our investigation of this problem will first be given. Then the detailed design of a long distance all optical bit-parallel WDM single-fiber link with 12 bit-parallel channels having 1 Gbytes/sec capacity is given. The speed-distance product for this link is 32 Gbytes/sec-km. Means to improve this speed-distance product using the pulse shepherding effect will be described. Finally, a detailed description of the BP-WDM component requirements is given.