Science.gov

Sample records for in-situ property measurements

  1. Granites: Relation of Properties in situ to Laboratory Measurements.

    PubMed

    Simmons, G; Nur, A

    1968-11-15

    The velocity of compressional waves and electrical resistivity in granite in situ measured in two 3-kilometer boreholes exhibits very little variation with depth, in contrast with the variation predicted from laboratory measurements on dry samples. These observations can be explained either by the absence of small open cracks in the rocks in situ or by the effects of complete saturation with water. The seismic velocities of many granites at shallow depths in the earth's crust may be significantly larger than was previously believed. Other properties are also affected; correction for the effect of cracks on thermal conductivity raises the average heat flow in shield areas by as much as 20 percent.

  2. In-situ physical properties measurements using crosswell acoustic data

    SciTech Connect

    Johnson, P.A.; Albright, J.N.

    1985-01-01

    Crosswell acoustic surveys enable the in-situ measurements of elastic moduli, Poisson's ratio, porosity, and apparent seismic Q of gas-bearing low-permeability formations represented at the Department of Energy Multi-Well Experiment (MWX) site near Rifle, Colorado. These measurements, except for Q, are compared with laboratory measurements on core taken from the same depths at which the crosswell measurements are made. Seismic Q determined in situ is compared to average values for sandstone. Porosity was determined from crosswell data using the empirical relationship between acoustic velocity, porosity, and effective pressure developed by Domenico. Domenico, S.N., ''Rock Lithology and Porosity Determination from Shear and compressional Wave Velocity,'' Geophysics, Vol. 49, No. 9, Aug. 1984, pp. 1188-1195. In-situ porosities are significantly greater than the core-derived values. Sources of the discrepancy may arise from (i) the underestimation of porosity that can result when Boyle's Law measurements are made on low-permeability core and (ii) the application of Dominico's relationship, which is developed for clean sands, to the mixed sandstone and shale lithologies represented at the MWX site. Values for Young's modulus and Poisson's ratio derived from crosswell measurements are comparable to values obtained from core. Apparent seismic Q measured in situ between wells is lower than Q measured on core and clearly shows the heterogeneity of sandstone deposited in a fluvial environment. 16 refs., 4 figs., 2 tabs.

  3. Epoxy and acrylate sterolithography resins: in-situ property measurements

    SciTech Connect

    Guess, T.R.; Chambers, R.S.; Hinnerichs, T.D.

    1996-01-01

    Stereolithography is a rapid prototyping method that is becoming an important product realization and concurrent engineering tool, with applications in advanced and agile manufacturing. During the build process, material behavior plays a significant role in the mechanics leading to internal stresses and, potentially, to distortion (curling) of parts. The goal of the ``Stereolithography Manufacturing Process Modeling and Optimization`` LDRD program was to develop engineering tools for improving overall part accuracy during the stereolithography build process. These tools include phenomenological material models of solidifying stereolithography photocurable resins and a 3D finite element architecture that incorporates time varying material behavior, laser path dependence, and structural linkage. This SAND report discusses the in situ measurement of shrinkage and force relaxation behavior of two photocurable resins, and the measurement of curl in simple cantilever beams. These studies directly supported the development of phenomenological material models for solidifying resins and provided experimental curl data to compare to model predictions.

  4. Comparison of cloud properties observed from in situ and satellite measurements

    NASA Astrophysics Data System (ADS)

    Noble, S. R.; Hudson, J. G.

    2013-12-01

    Climate is influenced by clouds reflecting radiation. Adjustments in cloud properties occur with changes to the cloud environment such as changes in aerosol or vertical velocity. These adjustments change the cloud radiative forcing. Three ways exist to study cloud properties: in situ observations, satellite observations, and modeling of cloud properties. Data sets from in situ measurements in field campaigns such as Physics of Stratocumulus Top (POST) (Hudson et al. 2010; Hudson and Noble 2013) provide good resolution of local cloud properties but are not extensive over time or globally. Satellites provide data coverage on a global scale and over long times but at infrequent periods locally. Uncertainties arise between these two methods when attempting to understand cloud properties and effects on radiative forcing. To understand these uncertainties, we compared MODIS data to vertical cloud pass data from the POST field campaign. Data from 9 in situ slant passes were compared to data from 9 satellite passes on 8 days. Figure 1 shows these comparisons of effective radius (re) (black) and cloud optical depth (COD) (red). COD from the satellite passes compares well with in situ data near the 1:1 line. The correlation coefficient (R) for COD is 0.95 with a slope (k) of 1.05. However, re is not near the 1:1 line and shows a steep k of 2.36, which suggests an over-prediction by the satellite observations, while R is only 0.57. Satellite re compared better to maximum in situ re which yielded a flatter k of 1.44 but an R of 0.59. Maximum re occurred a few meters below stratus cloud top that may suggest larger droplets dominate over cloud thickness in satellite observations. The satellite also over-predicts liquid water path (LWP, not shown) with a k of 1.42 and an R of 0.90. Because satellite re is over-predicting, calculations of environmental precursors become more difficult. However, COD is more related to albedo and observations compare well, which appears to validate

  5. In situ gas analysis for high pressure applications using property measurements

    NASA Astrophysics Data System (ADS)

    Moeller, J.; Span, R.; Fieback, T.

    2013-10-01

    As the production, distribution, and storage of renewable energy based fuels usually are performed under high pressures and as there is a lack of in situ high pressure gas analysis instruments on the market, the aim of this work was to develop a method for in situ high pressure gas analysis of biogas and hydrogen containing gas mixtures. The analysis is based on in situ measurements of optical, thermo physical, and electromagnetic properties in gas mixtures with newly developed high pressure sensors. This article depicts the calculation of compositions from the measured properties, which is carried out iteratively by using highly accurate equations of state for gas mixtures. The validation of the method consisted of the generation and measurement of several mixtures, of which three are presented herein: a first mixture of 64.9 mol. % methane, 17.1 mol. % carbon dioxide, 9 mol. % helium, and 9 mol. % ethane at 323 K and 423 K in a pressure range from 2.5 MPa to 17 MPa; a second mixture of 93.0 mol. % methane, 4.0 mol. % propane, 2.0 mol. % carbon dioxide, and 1.0 mol. % nitrogen at 303 K, 313 K, and 323 K in a pressure range from 1.2 MPa to 3 MPa; and a third mixture of 64.9 mol. % methane, 30.1 mol. % carbon dioxide, and 5.0 mol. % nitrogen at 303 K, 313 K, and 323 K in a pressure range from 2.5 MPa to 4 MPa. The analysis of the tested gas mixtures showed that with measured density, velocity of sound, and relative permittivity the composition can be determined with deviations below 1.9 mol. %, in most cases even below 1 mol. %. Comparing the calculated compositions with the generated gas mixture, the deviations were in the range of the combined uncertainty of measurement and property models.

  6. In situ methods for measuring thermal properties and heat flux on planetary bodies

    PubMed Central

    Kömle, Norbert I.; Hütter, Erika S.; Macher, Wolfgang; Kaufmann, Erika; Kargl, Günter; Knollenberg, Jörg; Grott, Matthias; Spohn, Tilman; Wawrzaszek, Roman; Banaszkiewicz, Marek; Seweryn, Karoly; Hagermann, Axel

    2011-01-01

    The thermo-mechanical properties of planetary surface and subsurface layers control to a high extent in which way a body interacts with its environment, in particular how it responds to solar irradiation and how it interacts with a potentially existing atmosphere. Furthermore, if the natural temperature profile over a certain depth can be measured in situ, this gives important information about the heat flux from the interior and thus about the thermal evolution of the body. Therefore, in most of the recent and planned planetary lander missions experiment packages for determining thermo-mechanical properties are part of the payload. Examples are the experiment MUPUS on Rosetta's comet lander Philae, the TECP instrument aboard NASA's Mars polar lander Phoenix, and the mole-type instrument HP3 currently developed for use on upcoming lunar and Mars missions. In this review we describe several methods applied for measuring thermal conductivity and heat flux and discuss the particular difficulties faced when these properties have to be measured in a low pressure and low temperature environment. We point out the abilities and disadvantages of the different instruments and outline the evaluation procedures necessary to extract reliable thermal conductivity and heat flux data from in situ measurements. PMID:21760643

  7. In-situ measurement of processing properties during fabrication in a production tool

    NASA Technical Reports Server (NTRS)

    Kranbuehl, D. E.; Haverty, P.; Hoff, M.; Loos, A. C.

    1988-01-01

    Progress is reported on the use of frequency-dependent electromagnetic measurements (FDEMs) as a single, convenient technique for continuous in situ monitoring of polyester cure during fabrication in a laboratory and manufacturing environment. Preliminary FDEM sensor and modeling work using the Loss-Springer model in order to develop an intelligent closed-loop, sensor-controlled cure process is described. FDEMs using impedance bridges in the Hz to MHz region is found to be ideal for automatically monitoring polyester processing properties continuously throughout the cure cycle.

  8. Optical closure in marine waters from in situ inherent optical property measurements.

    PubMed

    Lefering, Ina; Bengil, Fethi; Trees, Charles; Röttgers, Rüdiger; Bowers, David; Nimmo-Smith, Alex; Schwarz, Jill; McKee, David

    2016-06-27

    Optical closure using radiative transfer simulations can be used to determine the consistency of in situ measurements of inherent optical properties (IOPs) and radiometry. Three scattering corrections are applied to in situ absorption and attenuation profile data for a range of coastal and oceanic waters, but are found to have only very limited impact on subsequent closure attempts for these stations. Best-fit regressions on log-transformed measured and modelled downwards irradiance, Ed, and upwards radiance, Lu, profiles have median slopes between 0.92 - 1.24, revealing a tendency to underestimate Ed and Lu with depth. This is only partly explained by non-inclusion of fluorescence emission from CDOM and chlorophyll in the simulations. There are several stations where multiple volume scattering function related data processing steps perform poorly which suggests the potential existence of unresolved features in the modelling of the angular distribution of scattered photons. General optical closure therefore remains problematic, even though there are many cases in the data set where the match between measured and modelled radiometric data is within 25% RMS%E. These results are significant for applications that rely on optical closure e.g. assimilating ocean colour data into coupled physical-ecosystem models. PMID:27410565

  9. Proof-of-principle tests of the REKA method for in situ thermophysical property measurement

    SciTech Connect

    Danko, G.; Emert, G.

    1995-12-01

    It would be advantageous to measure rock thermophysical properties at Yucca Mountain around the exploratory drifts at some 500-1000 points in standard rockbolt holes. The in situ values, being primary site characteristics, would be applicable to (1) validate highly speculative empirical models for rockmass effects, (2) analyze the variability of rock properties at low cost, (3) identify initial convective effects, (4) monitor rock dryout due to ventilation, and (5) support hydrothermal site characterization. A scaled version of the thermal probe method, called REKA (Rapid Evaluation of K and Alpha) has been tested in the Mackay School of Mines Thermophysical Laboratory under different, controlled conditions in order to evaluate its application potential for field measurements when rockmass effects are present. The REKA method involves a single borehole probe with a heater and temperature measurement section. An elliptical temperature field is generated by the heater, and the temperature distribution along the length of the probe is recorded at several locations and at given time intervals for a period of 24 hours. The scaled REKA probe requires an approximately 0.9 m-deep (3 ft) hole which is 0.013 m (1/2 in) in diameter. The full-size probe version that has been used in underground mines requires approximately 1.8 m-deep (6 ft) hole with (0.045 m 1 3/4 in) diameter. Other probe sizes can also be selected in order to apply the method to the standard drillholes that are used for rockbolt installations. Three laboratory test series were conducted using different, controlled conditions in two host test beds to determine the response of the REKA probe to conditions that may be present during actual in situ measurements.

  10. In situ measurement system

    DOEpatents

    Lord, D.E.

    1980-11-24

    A multipurpose in situ underground measurement system comprising a plurality of long electrical resistance elements in the form of rigid reinforcing bars, each having an open loop hairpin configuration of shorter length than the other resistance elements. The resistance elements are arranged in pairs in a unitized structure, and grouted in place in the underground volume. Measurement means are provided for obtaining for each pair the electrical resistance of each element and the difference in electrical resistance of the paired elements, which difference values may be used in analytical methods involving resistance as a function of temperature. A scanner means sequentially connects the resistance-measuring apparatus to each individual pair of elements. A source of heating current is also selectively connectable for heating the elements to an initial predetermined temperature prior to electrical resistance measurements when used as an anemometer.

  11. Comparison of the aerosol optical properties and size distribution retrieved by sun photometer with in situ measurements at midlatitude

    NASA Astrophysics Data System (ADS)

    Chauvigné, Aurélien; Sellegri, Karine; Hervo, Maxime; Montoux, Nadège; Freville, Patrick; Goloub, Philippe

    2016-09-01

    Aerosols influence the Earth radiative budget through scattering and absorption of solar radiation. Several methods are used to investigate aerosol properties and thus quantify their direct and indirect impacts on climate. At the Puy de Dôme station, continuous high-altitude near-surface in situ measurements and low-altitude ground-based remote sensing atmospheric column measurements give the opportunity to compare the aerosol extinction measured with both methods over a 1-year period. To our knowledge, it is the first time that such a comparison is realised with continuous measurements of a high-altitude site during a long-term period. This comparison addresses to which extent near-surface in situ measurements are representative of the whole atmospheric column, the aerosol mixing layer (ML) or the free troposphere (FT). In particular, the impact of multi-aerosol layers events detected using lidar backscatter profiles is analysed. A good correlation between in situ aerosol extinction coefficient and aerosol optical depth (AOD) measured by the Aerosol Robotic Network (AERONET) sun photometer is observed with a correlation coefficient around 0.80, indicating that the in situ measurements station is representative of the overall atmospheric column. After filtering for multilayer cases and correcting for each layer optical contribution (ML and FT), the atmospheric structure seems to be the main factor influencing the comparison between the two measurement techniques. When the site lies in the ML, the in situ extinction represents 45 % of the sun photometer ML extinction while when the site lies within the FT, the in situ extinction is more than 2 times higher than the FT sun photometer extinction. Moreover, the assumption of a decreasing linear vertical aerosol profile in the whole atmosphere has been tested, significantly improving the instrumental agreement. Remote sensing retrievals of the aerosol particle size distributions (PSDs) from the sun photometer

  12. Airborne Sunphotometer Studies of Aerosol Properties and Effects, Including Closure Among Satellite, Suborbital Remote, and In situ Measurements

    NASA Technical Reports Server (NTRS)

    Russlee, Philip B.; Schmid, B.; Redemann, J.; Livingston, J. M.; Bergstrom, R. W.; Ramirez, S. A.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    Airborne sunphotometry has been used to measure aerosols from North America, Europe, and Africa in coordination with satellite and in situ measurements in TARFOX (1996), ACE-2 (1997), PRIDE (2000), and SAFARI 2000. Similar coordinated measurements of Asian aerosols are being conducted this spring in ACE-Asia and are planned for North American aerosols this summer in CLAMS. This paper summarizes the approaches used, key results, and implications for aerosol properties and effects, such as single scattering albedo and regional radiative forcing. The approaches exploit the three-dimensional mobility of airborne sunphotometry to access satellite scenes over diverse surfaces (including open ocean with and without sunglint) and to match exactly the atmospheric layers sampled by airborne in situ measurements and other radiometers. These measurements permit tests of the consistency, or closure, among such diverse measurements as aerosol size-resolved chemical composition; number or mass concentration; light extinction, absorption, and scattering (total, hemispheric back and 180 deg.); and radiative fluxes. In this way the airborne sunphotometer measurements provide a key link between satellite and in situ measurements that helps to understand any discrepancies that are found. These comparisons have led to several characteristic results. Typically these include: (1) Better agreement among different types of remote measurements than between remote and in situ measurements. (2) More extinction derived from transmission measurements than from in situ measurements. (3) Larger aerosol absorption inferred from flux radiometry than from in situ measurements. Aerosol intensive properties derived from these closure studies have been combined with satellite-retrieved fields of optical depth to produce fields of regional radiative forcing. We show results for the North Atlantic derived from AVHRR optical depths and aerosol intensive properties from TARFOX and ACE-2. Companion papers

  13. In Situ Measurements of Microphysical and Radiative Properties of Cirrus and Anvil Clouds

    NASA Astrophysics Data System (ADS)

    Lawson, P.; Baker, B.; Pilson, B.

    2003-12-01

    In situ microphysical and radiative properties of mid-latitude cirrus, anvil and tropical anvil clouds, based on research flights conducted with the SPEC Learjet, the NASA WB-57 and DC-8, and the University of North Dakota Citation research aircraft, are presented. The measurements were collected in Colorado, Utah, Oklahoma, Florida and Kwajalein. All of the research aircraft were equipped with a standard complement of microphysical sensors and optical probes, plus a cloud particle imager (CPI), which produces high-definition (2.3 micron pixel) digital images of ice particles. The CPI data provide improved measurements of particle shape and size, facilitating better calculations of radiative properties of cirrus and anvil clouds. Based on the measurements, average mid-latitude cirrus, and mid-latitude and tropical cirrus microphysical properties of particle size distribution, crystal habit, ice water content, extinction coefficient, effective radius and optical depth are derived. The data show a distinct difference between particle characteristics in mid-latitude cirrus and anvil clouds. In cirrus, the predominate crystal type (weighted by area or mass) is the bullet rosette, a polycrystalline structure typical of crystal formation at temperatures colder than -30 C. Conversely, although anvils occur at temperatures similar to cirrus, bullet rosettes are very rare in anvils. Instead crystal types in anvils are typical of those formed at temperatures warmer than - 30 C. There is also a notable difference in microphysical and radiative characteristics between mid-latitude, Florida, and tropical (Kwajalein) anvils. Tropical anvils are comprised mainly of single crystals, mostly irregular blocky-shapes. In mid-latitude and Florida anvils, there are more aggregates and often chains of small particles that may be formed as a result of the higher electric fields in continental clouds. The impact of crystal type on calculations of radiative transfer are also considered.

  14. In situ measurements of plasma properties during gas-condensation of Cu nanoparticles

    NASA Astrophysics Data System (ADS)

    Koten, M. A.; Voeller, S. A.; Patterson, M. M.; Shield, J. E.

    2016-03-01

    Since the mean, standard deviation, and modality of nanoparticle size distributions can vary greatly between similar input conditions (e.g., power and gas flow rate), plasma diagnostics were carried out in situ using a double-sided, planar Langmuir probe to determine the effect the plasma has on the heating of clusters and their final size distributions. The formation of Cu nanoparticles was analyzed using cluster-plasma physics, which relates the processes of condensation and evaporation to internal plasma properties (e.g., electron temperature and density). Monitoring these plasma properties while depositing Cu nanoparticles with different size distributions revealed a negative correlation between average particle size and electron temperature. Furthermore, the modality of the size distributions also correlated with the modality of the electron energy distributions. It was found that the maximum cluster temperature reached during plasma heating and the material's evaporation point regulates the growth process inside the plasma. In the case of Cu, size distributions with average sizes of 8.2, 17.3, and 24.9 nm in diameter were monitored with the Langmuir probe, and from the measurements made, the cluster temperatures for each deposition were calculated to be 1028, 1009, and 863 K. These values are then compared with the onset evaporation temperature of particles of this size, which was estimated to be 1059, 1068, and 1071 K. Thus, when the cluster temperature is too close to the evaporation temperature, less particle growth occurs, resulting in the formation of smaller particles.

  15. Mechanical properties of in situ demineralised human enamel measured by AFM nanoindentation

    NASA Astrophysics Data System (ADS)

    Finke, Manuela; Hughes, Julie A.; Parker, David M.; Jandt, Klaus D.

    2001-10-01

    Diet-induced demineralisation is one of the key factors in surface changes of tooth enamel, with soft drinks being a significant etiological agent. The first step in this dissolution process is characterised by a change in the mechanical properties of the enamel and a roughening of the surface. The objective of this pilot study was to measure early stages of in situ induced hardness changes of polished human enamel surfaces with high accuracy using a nanoindenter attached to an atomic force microscope (AFM). Human unerupted third molars were cleaned, sterilised with sodium hypochlorite, sectioned and embedded in epoxy resin. The outer enamel surface was polished and the samples partly covered with a tape, allowing a 2-mm-wide zone to be exposed to the oral environment. Samples were fitted in an intra-oral appliance, which was worn from 9 a.m. to 5 p.m. for one day. During this time the volunteer sipped 250 ml of a drink over 10 min periods at 9.00, 11.00, 13.00 and 15.00 h. Three different drinks, mineral water, orange juice and the prototype of a blackcurrant drink with low demineralisation potential were used in this study. At the end of the experiment the samples were detached from the appliance, the tape removed and the surfaces chemically cleaned. The surface hardness and reduced Young's modulus of the exposed and unexposed areas of each sample were determined. In addition, high resolution topographical AFM images were obtained. This study shows that by determining the hardness and reduced Young's modulus, the difference in demineralisation caused by the drinks can be detected and quantified before statistically significant changes in surface topography could be observed with the AFM. The maximum decrease in surface hardness and Young's modulus occurred in the samples exposed to orange juice, followed by those exposed to the blackcurrant drink, while exposure to water led to the same values as unexposed areas. A one-way ANOVA showed a statistically significant

  16. In Situ Mechanical Property Measurements of Amorphous Carbon-Boron Nitride Nanotube Nanostructures

    NASA Technical Reports Server (NTRS)

    Kim, Jae-Woo; Lin, Yi; Nunez, Jennifer Carpena; Siochi, Emilie J.; Wise, Kristopher E.; Connell, John W.; Smith, Michael W.

    2011-01-01

    To understand the mechanical properties of amorphous carbon (a-C)/boron nitride nanotube (BNNT) nanostructures, in situ mechanical tests are conducted inside a transmission electron microscope equipped with an integrated atomic force microscope system. The nanotube structure is modified with amorphous carbon deposited by controlled electron beam irradiation. We demonstrate multiple in situ tensile, compressive, and lap shear tests with a-C/BNNT hybrid nanostructures. The tensile strength of the a-C/BNNT hybrid nanostructure is 5.29 GPa with about 90 vol% of a-C. The tensile strength and strain of the end-to-end joint structure with a-C welding is 0.8 GPa and 5.2% whereas the lap shear strength of the side-by-side joint structure with a-C is 0.25 GPa.

  17. Sensing, Control, and In Situ Measurement of Coating Properties: An Integrated Approach Toward Establishing Process-Property Correlations

    NASA Astrophysics Data System (ADS)

    Sampath, S.; Srinivasan, V.; Valarezo, A.; Vaidya, A.; Streibl, T.

    2009-06-01

    Over the last decade there has been an explosion in terms of available tools for sensing the particle spray stream in thermal spray processes. This has led to considerable enhancement in our understanding of process reproducibility and reliability. Despite these advances, the linkage to coating properties has continued to be an enigma. This is partially due to the complex nature of the build-up process and the associated issues with measuring properties of these complex coatings. In this paper, we identify critical issues in processing-structure-property relations particularly with respect to the linkage to particle properties. Our goal is to demonstrate an integrated strategy, one that combines particle state sensing, with process mapping and extracting coating properties in situ through the development of robust and advanced curvature-based techniques. These techniques allow estimation of coating modulus, residual stress and, non-linear response of thermal sprayed ceramic coatings all within minutes of the deposition process. Finally, the integrated strategy examines the role of process maps for control of the spray stream as well as tailoring properties of thermal spray coatings. Examples of such studies for yttria-stabilized zirconia thermal barrier coatings are discussed.

  18. AeroCom INSITU Project: Comparison of Aerosol Optical Properties from In-situ Surface Measurements and Model Simulations

    NASA Astrophysics Data System (ADS)

    Schmeisser, L.; Andrews, E.; Schulz, M.; Fiebig, M.; Zhang, K.; Randles, C. A.; Myhre, G.; Chin, M.; Stier, P.; Takemura, T.; Krol, M. C.; Bian, H.; Skeie, R. B.; da Silva, A. M., Jr.; Kokkola, H.; Laakso, A.; Ghan, S.; Easter, R. C.

    2015-12-01

    AeroCom, an open international collaboration of scientists seeking to improve global aerosol models, recently initiated a project comparing model output to in-situ, surface-based measurements of aerosol optical properties. The model/measurement comparison project, called INSITU, aims to evaluate the performance of a suite of AeroCom aerosol models with site-specific observational data in order to inform iterative improvements to model aerosol modules. Surface in-situ data have the unique property of being traceable to physical standards, which is a big asset in accomplishing the overarching goal of bettering the accuracy of aerosol processes and predicative capability of global climate models. The INSITU project looks at how well models reproduce aerosol climatologies on a variety of time scales, aerosol characteristics and behaviors (e.g., aerosol persistence and the systematic relationships between aerosol optical properties), and aerosol trends. Though INSITU is a multi-year endeavor, preliminary phases of the analysis, using GOCART and other models participating in this AeroCom project, show substantial model biases in absorption and scattering coefficients compared to surface measurements, though the sign and magnitude of the bias varies with location and optical property. Spatial patterns in the biases highlight model weaknesses, e.g., the inability of models to properly simulate aerosol characteristics at sites with complex topography (see Figure 1). Additionally, differences in modeled and measured systematic variability of aerosol optical properties suggest that some models are not accurately capturing specific aerosol co-dependencies, for example, the tendency of in-situ surface single scattering albedo to decrease with decreasing aerosol extinction coefficient. This study elucidates specific problems with current aerosol models and suggests additional model runs and perturbations that could further evaluate the discrepancies between measured and modeled

  19. In-Situ Real Time Measurements of Molten Glass Properties, Final Report

    SciTech Connect

    Robert De Saro; Joe Craparo

    2007-12-16

    Energy Research Company (ERCo) of Staten Island, NY has developed a sensor capable of measuring in situ and in real time, both the elemental composition and the temperature of molten glass. A prototype sensor has been designed, constructed and tested in ERCo's laboratory. The sensor was used to collect atomic emission spectra from molten fiberglass via Laser Induced Breakdown Spectroscopy (LIBS). From these spectra, we were able to readily identify all elements of interest (B, Si, Ca, Fe, Mg, Na, Sr, Al). The high signal-to-background signals achieved suggest that data from the sensor can be used to determine elemental concentrations, either through calibration curves or using ERCo's calibrationless method. ERCo's technology fits in well with DOE's Glass Industry Technology Roadmap which emphasizes the need for accurate process and feedstock sensors. Listed first under technological barriers to increased production efficiency is the 'Inability to accurately measure and control the production process'. A large-scale glass melting furnace, developed by SenCer Inc. of Penn Yan, NY was installed in ERCo's laboratory to ensure that a large enough quantity of glass could be melted and held at temperature in the presence of the water-cooled laser sensor without solidifying the glass.

  20. Dry fracture method for simultaneous measurement of in-situ stress state and material properties

    SciTech Connect

    Serata, S.; Oka, S.; Kikuchi, S.

    1996-04-01

    Based on the dry fracture principle, a computerized borehole probe has been developed to measure stress state and material properties, simultaneously. The probe is designed to obtain a series of measurements in a continuing sequence along a borehole length, without any interruptive measures, such as resetting packers, taking indentation of borehole wall, overcoming, etc. The new dry fracture probe for the single fracture method is designed to overcome the difficulties posed by its ancestor which was based on the double fracture method. The accuracy of the single fracture method is confirmed by a close agreement with the theory, FE modeling and laboratory testing.

  1. In-situ measurements of the mixing state and optical properties of soot with implications for radiative forcing estimates

    PubMed Central

    Moffet, Ryan C.; Prather, Kimberly A.

    2009-01-01

    Our ability to predict how global temperatures will change in the future is currently limited by the large uncertainties associated with aerosols. Soot aerosols represent a major research focus as they influence climate by absorbing incoming solar radiation resulting in a highly uncertain warming effect. The uncertainty stems from the fact that the actual amount soot warms our atmosphere strongly depends on the manner and degree in which it is mixed with other species, a property referred to as mixing state. In global models and inferences from atmospheric heating measurements, soot radiative forcing estimates currently differ by a factor of 6, ranging between 0.2–1.2 W/m2, making soot second only to CO2 in terms of global warming potential. This article reports coupled in situ measurements of the size-resolved mixing state, optical properties, and aging timescales for soot particles. Fresh fractal soot particles dominate the measured absorption during peak traffic periods (6–9 AM local time). Immediately after sunrise, soot particles begin to age by developing a coating of secondary species including sulfate, ammonium, organics, nitrate, and water. Based on these direct measurements, the core-shell arrangement results in a maximum absorption enhancement of 1.6× over fresh soot. These atmospheric observations help explain the larger values for soot forcing measured by others and will be used to obtain closure in optical property measurements to reduce one of the largest remaining uncertainties in climate change. PMID:19581581

  2. Optical properties and radiation stability of submicro- and nanopowders titanium dioxide measured in situ

    NASA Astrophysics Data System (ADS)

    Mikhailov, M. M.; Neshchimenko, V. V.; Yuryev, S. A.

    2016-04-01

    This study carried out an in situ and external investigation on the reflective spectra of micro- and nanopowders titanium dioxide before and after irradiation by 30 keV electrons. The particle sizes range from 60-240 nm. It was established that the decrease in the particle size leads to an increase in intrinsic defects. The particles with intrinsic defects are then transformed into absorption centers during irradiation as a result of optical degradation of TiO2 powders. High radiation stability has particle sizes range from 80-160 nm.

  3. The analysis of in situ and retrieved aerosol properties measured during three airborne field campaigns

    NASA Astrophysics Data System (ADS)

    Corr, Chelsea A.

    Aerosols can directly influence climate, visibility, and photochemistry by scattering and absorbing solar radiation. Aerosol chemical and physical properties determine how efficiently a particle scatters and/or absorbs incoming short-wave solar radiation. Because many types of aerosol can act as nuclei for cloud droplets (CCN) and a smaller population of airborne particles facilitate ice crystal formation (IN), aerosols can also alter cloud-radiation interactions which have subsequent impacts on climate. Thus aerosol properties determine the magnitude and sign of both the direct and indirect impacts of aerosols on radiation-dependent Earth System processes. This dissertation will fill some gaps in our understanding of the role of aerosol properties on aerosol absorption and cloud formation. Specifically, the impact of aerosol oxidation on aerosol spectral (350nm < lambda< 500nm) absorption was examined for two biomass burning plumes intercepted by the NASA DC-S aircraft during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) mission in Spring and Summer 2008. Spectral aerosol single scattering albedo (SSA) retrieved using actinic flux measured aboard the NASA DC-8 was used to calculate the aerosol absorption Angstrom exponents (AAE) for a 6-day-old plume on April 17 th and a 3-hour old plume on June 29th. Higher AAE values for the April 17th plume (6.78+/-0.38) indicate absorption by aerosol was enhanced in the ultraviolet relative to the visible portion of the short-wave spectrum in the older plume compared to the fresher plume (AAE= 3.34 0.11). These differences were largely attributed to the greater oxidation of the organic aerosol in the April 17th plume which can arise either from the aging of primary organic aerosol or the formation of spectrally-absorbing secondary organic aerosol. The validity of the actinic flux retrievals used above were also evaluated in this work by the comparison of SSA retrieved using

  4. In-situ measurement system

    DOEpatents

    Lord, David E.

    1983-01-01

    A multipurpose in situ underground measurement system comprising a plurality of long electrical resistance elements in the form of rigid reinforcing bars, each having an open loop "hairpin" configuration of shorter length than the other resistance elements. The resistance elements are arranged in pairs in a unitized structure, and grouted in place in the underground volume. The electrical resistance of each element and the difference in electrical resistance of the paired elements are obtained, which difference values may be used in analytical methods involving resistance as a function of temperature. A scanner sequentially connects the resistance-measuring apparatus to each individual pair of elements. A source of heating current is also selectively connectable for heating the elements to an initial predetermined temperature prior to electrical resistance measurements when used as an anemometer.

  5. Real-time in situ measurements of volcanic plume physico-chemical properties using Controlled METeorological balloons

    NASA Astrophysics Data System (ADS)

    Durant, Adam; Voss, Paul; Watson, Matthew; Roberts, Tjarda; Thomas, Helen; Prata, Fred; Sutton, Jeff; Mather, Tamsin; Witt, Melanie; Patrick, Matthew

    2010-05-01

    While the climatic effects of volcanogenic sulphate aerosol in the stratosphere are well characterised, the nature and global impact of sustained tropospheric volcanic degassing is less well understood. In situ measurement of volcanic emissions can be used to understand plume processes (e.g., microphysics and chemistry), and used to validate and improve remote sensing techniques. New developments in sensor and communication technologies have led to the production of miniaturized lightweight unmanned atmospheric measurement platforms. Controlled METeorological (CMET) balloons collect real-time observations of atmospheric physico-chemical properties at altitudes of up to 5 km for hours or even days at a time. Standard measurements include pressure (± 10 mb), aspirated temperature (± 0.3 C), relative humidity (± 5 %) and location (GPS position ± 5 m horizontal, ± 50 m vertical). Balloon platform-based measurements of volcanic plume properties were made for the first time using CMET balloons equipped with miniature electrochemical sensors during the eruption of Halema'uma'u crater (Kilauea) in Hawai'i in 2008. In addition, multiple measurement platforms were simultaneously deployed that included (1) ground-based remote measurements (mini-DOAS and UV camera); (2) satellite-based sensors (MODIS and OMI); and (3) in situ sampling at the emission source using ground-based electrochemical sensor instrumentation. During the 25 July 2008 flight, a single CMET balloon remained in the plume and collected data for several hours. Ratios of [H2O] and [SO2] correlate in proximal regions of the plume, though were found to anti-correlate further downwind. Correlation is explained through co-emission of SO2 and H2O at source, as has been frequently previously observed e.g. by FTIR. Anti-correlation of [H2O] and [SO2] ratios has not previously been reported and may reflect dehydration of the aged plume through condensation of water vapour on volcanogenic sulphate aerosol. The

  6. In situ measurements of aerosol mass concentration and radiative properties in Xianghe, southeast of Beijing

    NASA Astrophysics Data System (ADS)

    Chaudhry, Zahra; Martins, J. Vanderlei; Li, Zhanqing; Tsay, Si-Chee; Chen, Hongbin; Wang, Pucai; Wen, Tianxue; Li, Can; Dickerson, Russell R.

    2007-12-01

    As a part of the EAST-AIRE study, Nuclepore filters were collected in two size ranges (coarse, 2.5 μm < d < 10 μm, and fine, d < 2.5 μm) from January to May 2005 in Xianghe, about 70 km southeast of Beijing, and analyzed for aerosol mass concentration, spectral absorption efficiency and absorption coefficient. Twelve-hour aerosol mass concentration measurements showed an average concentration of 120 μg/m3 in the coarse mode and an average concentration of 25 μg/m3 in the fine mode. To determine how representative ground-based measurements are of the total column, the mass concentration data was compared with AERONET AOT at 500 nm and AERONET size distribution data. The vertical distribution of the aerosols were studied with a micropulse lidar and in the cases where the vertical column was found to be fairly homogenous, the comparisons of the filter results with AERONET agreed favorably, while in the cases of inhomogeneity, the comparisons have larger disagreement. For fine mode aerosols, the average spectral absorption efficiency equates well to a λ-1 model, while the coarse mode shows a much flatter spectral dependence, consistent with large particle models. The coarse mode absorption efficiency was compatible with that of the fine mode in the NIR region, indicating the much stronger absorption of the coarse mode due to its composition and sizable mass. Single scattering albedo results are presented from a combination between absorption coefficients derived from the filter measurements, from a PSAP and from a three-wavelength Nephelometer.

  7. Mechanical characterization device for in situ measurement of nanomechanical properties of micro/nanostructures

    NASA Astrophysics Data System (ADS)

    Singh, Utkarsha; Prakash, Vikas; Abramson, Alexis R.; Chen, Wei; Qu, Liangti; Dai, Liming

    2006-08-01

    A characterization device was developed for nanomechanical testing on one-dimensional micro/nanostructures. The tool consists of a nanomanipulator, a three-plate capacitive transducer, and associated probes, and is operated inside a scanning electron microscope. The transducer independently measures force and displacement with micronewton and nanometer sale resolutions, respectively. Tensile testing of a polyaniline microfiber (diameter ˜1μm) demonstrated the capabilities of the system. Engineering stress versus strain curves exhibited two distinct regions with different Young's moduli. Failure at the probe-sample weld occurred at ˜67MPa, suggesting that polyaniline microfibers exhibit a yield stress that is higher than most comparable bulk polymers.

  8. Investigation of the feasibility of in-situ dielectric property measurements on neutron-irradiated ceramic insulators

    SciTech Connect

    Goulding, R.H.; Zinkle, S.J.

    1996-04-01

    Computer modeling and experimental benchtop tests have demonstrated that a capacitively loaded resonant coaxial cavity can produce accurate in-situ measurements of the loss tangent and dielectric constant of ceramic insulators at a frequency of {approx}80 MHZ during fission reactor irradiation. The start of the reactor irradiations has been postponed indefinitely due to budgetary constraints.

  9. Practical application of in situ aerosol measurement

    SciTech Connect

    O`Hern, T.J.; Rader, D.J.

    1993-09-01

    The use of in situ, real-time measurement techniques permits the characterization of airborne droplets and particles under conditions where traditional sampling methods can fail. For example, sampling method rely on the ability to sample and transport particles without biasing the properties of interest, and often are not applicable in harsh environment. Although in situ methods offer unique opportunities in these cases, these techniques introduce new concerns and must be used carefully if accurate measurement are to be made. Several in situ measurement techniques are reviewed here. As the field is rapidly evolving, the discussion is limited to those techniques which: (1) are commercially available, (2) provide real-time output, (3) measure the aerosol size distribution. Discussion is divided between single particle counters (which provide a flux-based or temporal measurement) and ensemble techniques (which provide a concentration-based or spatial measurement). Specific techniques discussed include phase Doppler, Mie scattering, and Fraunhofer diffraction, and commercial instruments based on these techniques.

  10. In-Situ Measurements of Aerosol Optical and Hygroscopic Properties at the Look Rock Site during SOAS 2013

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Zimmermann, K.; Bertram, T. H.; Corrigan, A. L.; Guzman, J. M.; Russell, L. M.; Budisulistiorini, S.; Li, X.; Surratt, J. D.; Hicks, W.; Bairai, S. T.; Cappa, C. D.

    2013-12-01

    One of the main goals of the Southern Oxidant and Aerosol Study (SOAS) is to characterize the climate-relevant properties of aerosols over the southeastern United States at the interface of biogenic and anthropogenic emissions. As part of the SOAS campaign, the UCD cavity ringdown/photoacoustic spectrometer was deployed to make in-situ measurements of aerosol light extinction, absorption and sub-saturated hygroscopicity at the Look Rock site (LRK) in the Great Smoky Mountains National Park, TN from June 1 to July 15, 2013. The site is influenced by substantial biogenic emissions with varying impacts from anthropogenic pollutants, allowing for direct examination of the optical and hygroscopic properties of anthropogenic-influenced biogenic secondary organic aerosols (SOA). During the experiment period, the average dry aerosol extinction (Bext), absorption (Babs) coefficients and single scattering albedo (SSA) at 532 nm were 30.3 × 16.5 Mm-1, 1.12 × 0.78 Mm-1 and 0.96 × 0.06. The Babs at 532 nm was well correlated (r2 = 0.79) with the refractory black carbon (rBC) number concentration determined by a single particle soot spectrometer (SP2). The absorption by black carbon (BC), brown carbon (BrC) and the absorption enhancement due to the 'lensing' effect were quantified by comparing the Babs of ambient and thermo-denuded aerosols at 405 nm and 532 nm. The optical sub-saturated hygroscopic growth factor was derived from extinction and particle size distribution measurements at dry and elevated relative humidity. In addition, to explore the extent to which ammonia mediated chemistry leads to BrC formation, as suggested in recent laboratory studies(1,2), we performed an NH3 perturbation experiment in-situ for 1 week during the study, in which ambient aerosols were exposed to approximately 100 ppb NH3 with a residence time of ~ 3hr. The broader implications of these observational data at LRK will be discussed in the context of the concurrent gas and aerosol chemical

  11. REAL-TIME IN-SITU MEASUREMENT OF MATERIAL ELASTIC PROPERTIES IN A HIGH GAMMA IRRADIATION ENVIRONMENT

    SciTech Connect

    Ken Telschow; Rob Schley; Dave Cottle

    2006-05-01

    The first measurements of elastic vibrations of an object in-situ to a high gamma irradiation field using a laser coupled resonant ultrasound method are described. A vibration mode of an Inconel hollow capped cylinder was measured throughout a period of 170 hours as the gamma radiation field was increased to 104 Gray/hour. The vibration mode frequency was observed to change in a manner consistent with the temperature dependence of the elastic stiffness coefficients of the material. These results illustrate the efficacy of the laser approach for real-time resonant ultrasound measurements in this severely hostile nuclear environment.

  12. In situ measurements of aerosols optical properties and number size distributions in a subarctic coastal region of Norway

    NASA Astrophysics Data System (ADS)

    Mogo, S.; Cachorro, V. E.; Lopez, J. F.; Montilla, E.; Torres, B.; Rodríguez, E.; Bennouna, Y.; de Frutos, A. M.

    2011-12-01

    In situ measurements of aerosol optical properties were made in the summer of 2008 at the ALOMAR station facility (69°16 N, 16°00 E), located at a rural site in the north of the island of Andøya (Vesterålen archipelago), approximately 300 km north of the Arctic Circle. The extended three-month campaign was part of the POLARCAT Project (Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols, and Transport) of the International Polar Year (IPY-2007-2008). Its goal was to characterize the aerosols of this sub-Arctic area, which are frequently transported to the Arctic region. The ambient light-scattering coefficient, σs (550 nm), at ALOMAR had a measured hourly mean value of 5.41 Mm-1 (StD = 3.55 Mm-1), and the light-absorption coefficient, σa (550 nm), had a measured hourly mean value of 0.40 Mm-1 (StD = 0.27 Mm-1). The scattering/absorption Ångström exponents, αs,a, are used for a detailed analysis of the variations of the spectral shape of σs,a. Whereas αs demonstrates the presence of two particle sizes corresponding to two types of aerosols, the αa demonstrates only one type of absorbing aerosol particles. Values of αa above 1 were not observed. The single-scattering albedo, ω0, ranged from 0.62 to 0.99 (mean = 0.91, StD = 0.05), and the relationships of this property to the absorption/scattering coefficients and the Ångström exponents are presented. The concentration of the particles was monitored using a scanning mobility particle sizer (SMPS), an aerodynamic particle sizer (APS) and an ultrafine condensation particle counter (UCPC). The shape of the median size distribution of the particles in the submicrometer fraction was bimodal, and the submicrometer, micrometer and total concentrations presented hourly mean values of 1277 cm3 (StD = 1563 cm3), 1 cm3 (StD = 1 cm3) and 2463 cm3 (StD = 4251 cm3), respectively. The modal correlations were investigated, and the concentration of particles

  13. In situ optical measurements of Chang'E-3 landing site in Mare Imbrium: 2. Photometric properties of the regolith

    NASA Astrophysics Data System (ADS)

    Jin, Weidong; Zhang, Hao; Yuan, Ye; Yang, Yazhou; Shkuratov, Yuriy G.; Lucey, Paul G.; Kaydash, Vadim G.; Zhu, Meng-Hua; Xue, Bin; Di, Kaichang; Xu, Bin; Wan, Wenhui; Xiao, Long; Wang, Ziwei

    2015-10-01

    The panorama cameras onboard the Yutu Rover of the Chang'E-3 lunar mission acquired hundreds of high-resolution color images of the lunar surface and captured the first in situ lunar opposition effect (OE) since the Apollo era. We extracted the phase curve and the color ratio in three bands with the phase angle range from 2° to 141°. Photometric inversions using the Hapke model reveal that submicroscopic dusts are present in the landing area and both the coherent backscattering and the shadow hiding are responsible for the strong OE. Compared with spaceborne measurements, the grains in the landing site are brighter, more transparent, and appear to be better crystallized than the average maria basaltic grains. The results show that the phase-reddening effect appears to be present in the in situ phase curves. The current phase curve can be used as the ground-truth validations of any future spaceborne phase curve measurement over the landing site region.

  14. In situ PEM fuel cell water measurements

    SciTech Connect

    Borup, Rodney L; Mukundan, Rangachary; Davey, John R; Spendalow, Jacob S

    2008-01-01

    Efficient PEM fuel cell performance requires effective water management. The materials used, their durability, and the operating conditions under which fuel cells run, make efficient water management within a practical fuel cell system a primary challenge in developing commercially viable systems. We present experimental measurements of water content within operating fuel cells. in response to operational conditions, including transients and freezing conditions. To help understand the effect of components and operations, we examine water transport in operating fuel cells, measure the fuel cell water in situ and model the water transport within the fuel cell. High Frequency Resistance (HFR), AC Impedance and Neutron imaging (using NIST's facilities) were used to measure water content in operating fuel cells with various conditions, including current density, relative humidity, inlet flows, flow orientation and variable GDL properties. Ice formation in freezing cells was also monitored both during operation and shut-down conditions.

  15. Study of aerosol microphysical properties profiles retrieved from ground-based remote sensing and aircraft in-situ measurements during a Saharan dust event

    NASA Astrophysics Data System (ADS)

    Granados-Muñoz, M. J.; Bravo-Aranda, J. A.; Baumgardner, D.; Guerrero-Rascado, J. L.; Pérez-Ramírez, D.; Navas-Guzmán, F.; Veselovskii, I.; Lyamani, H.; Valenzuela, A.; Olmo, F. J.; Titos, G.; Andrey, J.; Chaikovsky, A.; Dubovik, O.; Gil-Ojeda, M.; Alados-Arboledas, L.

    2015-09-01

    In this work we present an analysis of mineral dust optical and microphysical properties obtained from different retrieval techniques applied to active and passive remote sensing measurements, including a comparison with simultaneous in-situ aircraft measurements. Data were collected in a field campaign performed during a mineral dust outbreak a Granada, Spain, experimental site (37.16° N, 3.61° W, 680 m a.s.l.) on the 27 June 2011. Column-integrated properties are provided by sun- and star-photometry which allows a continuous evaluation of the mineral dust optical properties during both day and night-time. Both the Linear Estimation and AERONET (Aerosol Robotic Network) inversion algorithms are applied for the retrieval of the column-integrated microphysical particle properties. In addition, vertically-resolved microphysical properties are obtained from a multi-wavelength Raman lidar system included in EARLINET (European Aerosol Research Lidar Network), by using both LIRIC (Lidar Radiometer Inversion Code) algorithm during daytime and an algorithm applied to the Raman measurements based on the regularization technique during night-time. LIRIC retrievals reveal several dust layers between 3 and 5 km a.s.l. with volume concentrations of the coarse spheroid mode up to 60 μm3 cm-3. The combined use of the regularization and LIRIC methods reveals the night-to-day evolution of the vertical structure of the mineral dust microphysical properties and offers complementary information to that from column-integrated variables retrieved from passive remote sensing. Additionally, lidar depolarization profiles and LIRIC retrieved volume concentration are compared with aircraft in-situ measurements. This study presents for the first time a comparison of both volume concentration and dust particle polarization ratios measured with in-situ and remote sensing techniques. Results for the depolarization measurements in the dust layer indicate reasonable agreement within the

  16. In-situ property measurements on laser-drawn strands of SL 5170 epoxy and SL 5149 acrylate

    SciTech Connect

    Guess, T.R.; Chambers, R.S.

    1995-08-01

    Material behavior plays a significant role in the mechanics leading to internal stresses and, potentially, to distortion (curling) of parts as they are built by stereolithography processes that utilize photocuring resins. A study is underway to generate material properties that can be used to develop phenomenological material models of epoxy and acrylate resins. Strand tests are performed in situ in a 3D System`s SLA-250 machine; strands are drawn by either single or multiple exposures of the resin to a laser beam. Linear shrinkage, cross-sectional areas, cure shrinkage forces and stress-strain data are presented. Also, the curl in cantilever beam specimens, built with different draw patterns, are compared.

  17. Quantitative optical coherence elastography based on fiber-optic probe for in situ measurement of tissue mechanical properties.

    PubMed

    Qiu, Yi; Wang, Yahui; Xu, Yiqing; Chandra, Namas; Haorah, James; Hubbi, Basil; Pfister, Bryan J; Liu, Xuan

    2016-02-01

    We developed a miniature quantitative optical coherence elastography (qOCE) instrument with an integrated Fabry-Perot force sensor, for in situ elasticity measurement of biological tissue. The technique has great potential for biomechanics modeling and clinical diagnosis. We designed the fiber-optic qOCE probe that was used to exert a compressive force to deform tissue at the tip of the probe. Using the space-division multiplexed optical coherence tomography (OCT) signal detected by a spectral domain OCT engine, we were able to quantify the probe deformation that was proportional to the force applied, and to quantify the tissue deformation corresponding to the external stimulus. Simultaneous measurement of force and displacement allowed us to extract Young's modulus of biological tissue. We experimentally calibrated our qOCE instrument, and validated its effectiveness on tissue mimicking phantoms and biological tissues.

  18. Quantitative optical coherence elastography based on fiber-optic probe for in situ measurement of tissue mechanical properties.

    PubMed

    Qiu, Yi; Wang, Yahui; Xu, Yiqing; Chandra, Namas; Haorah, James; Hubbi, Basil; Pfister, Bryan J; Liu, Xuan

    2016-02-01

    We developed a miniature quantitative optical coherence elastography (qOCE) instrument with an integrated Fabry-Perot force sensor, for in situ elasticity measurement of biological tissue. The technique has great potential for biomechanics modeling and clinical diagnosis. We designed the fiber-optic qOCE probe that was used to exert a compressive force to deform tissue at the tip of the probe. Using the space-division multiplexed optical coherence tomography (OCT) signal detected by a spectral domain OCT engine, we were able to quantify the probe deformation that was proportional to the force applied, and to quantify the tissue deformation corresponding to the external stimulus. Simultaneous measurement of force and displacement allowed us to extract Young's modulus of biological tissue. We experimentally calibrated our qOCE instrument, and validated its effectiveness on tissue mimicking phantoms and biological tissues. PMID:26977372

  19. Quantitative optical coherence elastography based on fiber-optic probe for in situ measurement of tissue mechanical properties

    PubMed Central

    Qiu, Yi; Wang, Yahui; Xu, Yiqing; Chandra, Namas; Haorah, James; Hubbi, Basil; Pfister, Bryan J.; Liu, Xuan

    2016-01-01

    We developed a miniature quantitative optical coherence elastography (qOCE) instrument with an integrated Fabry-Perot force sensor, for in situ elasticity measurement of biological tissue. The technique has great potential for biomechanics modeling and clinical diagnosis. We designed the fiber-optic qOCE probe that was used to exert a compressive force to deform tissue at the tip of the probe. Using the space-division multiplexed optical coherence tomography (OCT) signal detected by a spectral domain OCT engine, we were able to quantify the probe deformation that was proportional to the force applied, and to quantify the tissue deformation corresponding to the external stimulus. Simultaneous measurement of force and displacement allowed us to extract Young’s modulus of biological tissue. We experimentally calibrated our qOCE instrument, and validated its effectiveness on tissue mimicking phantoms and biological tissues. PMID:26977372

  20. In situ PEM fuel cell water measurements

    SciTech Connect

    Borup, Rodney L; Mukundan, Rangachary; Davey, John R; Spendelow, Jacob S; Hussey, Daniel S; Jacobson, David L; Arif, Muhammad

    2009-01-01

    Efficient PEM (Polymer Electrolyte Membrane) fuel cell performance requires effective water management. To achieve a deeper understanding of water transport and performance issues associated with water management, we have conducted in situ water examinations to help understand the effects of components and operations. High Frequency Resistance (HFR), AC Impedance and Neutron imaging were used to measure water content in operating fuel cells, with various conditions, including current density, relative humidity, inlet flows, flow orientation and variable Gas Diffusion Layer (GDL) properties. High resolution neutron radiography was used to image fuel cells during a variety of conditions. The effect of specific operating conditions, including flow direction (co-flow or counter-flow) was examined. Counter-flow operation was found to result in higher water content than co-flow operation, which correlates to lower membrane resistivity. A variety of cells were used to quantify the membrane water in situ during exposure to saturated gases, during fuel cell operation, and during hydrogen pump operation. The quantitative results show lower membrane water content than previous results suggested.

  1. Experimental Measurement of In Situ Stress

    NASA Astrophysics Data System (ADS)

    Tibbo, Maria; Milkereit, Bernd; Nasseri, Farzine; Schmitt, Douglas; Young, Paul

    2016-04-01

    The World Stress Map data is determined by stress indicators including earthquake focal mechanisms, in situ measurement in mining, oil and gas boreholes as well as the borehole cores, and geologic data. Unfortunately, these measurements are not only infrequent but sometimes infeasible, and do not provide nearly enough data points with high accuracy to correctly infer stress fields in deep mines around the world. Improvements in stress measurements of Earth's crust is fundamental to several industries such as oil and gas, mining, nuclear waste management, and enhanced geothermal systems. Quantifying the state of stress and the geophysical properties of different rock types is a major complication in geophysical monitoring of deep mines. Most stress measurement techniques involve either the boreholes or their cores, however these measurements usually only give stress along one axis, not the complete stress tensor. The goal of this project is to investigate a new method of acquiring a complete stress tensor of the in situ stress in the Earth's crust. This project is part of a comprehensive, exploration geophysical study in a deep, highly stressed mine located in Sudbury, Ontario, Canada, and focuses on two boreholes located in this mine. These boreholes are approximately 400 m long with NQ diameters and are located at depths of about 1300 - 1600 m and 1700 - 2000 m. Two borehole logging surveys were performed on both boreholes, October 2013 and July 2015, in order to perform a time-lapse analysis of the geophysical changes in the mine. These multi-parameter surveys include caliper, full waveform sonic, televiewer, chargeability (IP), and resistivity. Laboratory experiments have been performed on borehole core samples of varying geologies from each borehole. These experiments have measured the geophysical properties including elastic modulus, bulk modulus, P- and S-wave velocities, and density. The apparatus' used for this project are geophysical imaging cells capable

  2. A comparative study of aerosol microphysical properties retrieved from ground-based remote sensing and aircraft in situ measurements during a Saharan dust event

    NASA Astrophysics Data System (ADS)

    José Granados-Muñoz, María; Bravo-Aranda, Juan Antonio; Baumgardner, Darrel; Guerrero-Rascado, Juan Luis; Pérez-Ramírez, Daniel; Navas-Guzmán, Francisco; Veselovskii, Igor; Lyamani, Hassan; Valenzuela, Antonio; José Olmo, Francisco; Titos, Gloria; Andrey, Javier; Chaikovsky, Anatoli; Dubovik, Oleg; Gil-Ojeda, Manuel; Alados-Arboledas, Lucas

    2016-03-01

    In this work we present an analysis of aerosol microphysical properties during a mineral dust event taking advantage of the combination of different state-of-the-art retrieval techniques applied to active and passive remote sensing measurements and the evaluation of some of those techniques using independent data acquired from in situ aircraft measurements. Data were collected in a field campaign performed during a mineral dust outbreak at the Granada, Spain, experimental site (37.16° N, 3.61° W, 680 m a.s.l.) on 27 June 2011. Column-integrated properties are provided by sun- and star-photometry, which allows for a continuous evaluation of the mineral dust optical properties during both day and nighttime. Both the linear estimation and AERONET (Aerosol Robotic Network) inversion algorithms are applied for the retrieval of the column-integrated microphysical particle properties. In addition, vertically resolved microphysical properties are obtained from a multi-wavelength Raman lidar system included in EARLINET (European Aerosol Research Lidar Network), by using both LIRIC (Lidar Radiometer Inversion Code) algorithm during daytime and an algorithm applied to the Raman measurements based on the regularization technique during nighttime. LIRIC retrievals reveal the presence of dust layers between 3 and 5 km a.s.l. with volume concentrations of the coarse spheroid mode up to 60 µm3 cm-3. The combined use of the regularization and LIRIC methods reveals the night-to-day evolution of the vertical structure of the mineral dust microphysical properties and offers complementary information to that from column-integrated variables retrieved from passive remote sensing. Additionally, lidar depolarization profiles and LIRIC retrieved volume concentration are compared with aircraft in situ measurements. This study presents for the first time a comparison of the total volume concentration retrieved with LIRIC with independent in situ measurements, obtaining agreement within

  3. Deriving optical properties of Mahakam Delta coastal waters, Indonesia using in situ measurements and ocean color model inversion

    NASA Astrophysics Data System (ADS)

    Budhiman, Syarif; Suhyb Salama, Mhd.; Vekerdy, Zoltán; Verhoef, Wouter

    2012-03-01

    The development of an operational water quality monitoring method based on remote sensing data requires information on the apparent and inherent optical properties of water (AOP and IOP respectively). This study was performed to determine the apparent and inherent optical properties of coastal waters of the Mahakam Delta, Kalimantan, Indonesia. Inherent optical properties (IOPs) were derived from above-water radiometric measurements and ocean color model inversion. Retrieved IOPs and measured concentrations show good agreement both for total suspended matter (TSM) and chlorophyll a (Chl a) (R2 = 0.72 and 0.80 respectively). The linear relationship between the retrieved IOPs and the measured concentrations was then used to estimate the specific inherent optical properties (SIOPs) using the basic equation of the Lambert-Beer law. The specific backscattering coefficient of TSM (bb,TSM∗(550)) was found to be 0.0087 m2 g-1, and the specific absorption coefficient of Chl a (aChl∗(440)) was found to be 0.023 m2 g-1 in the Mahakam Delta. The estimated values of SIOP for TSM and Chl a could be considered spatially constant for the Mahakam Delta, and resulted in reliable estimates of TSM and Chl a concentrations (R2 = 0.84 and 0.85 respectively). The specific backscattering coefficient of TSM found in this study is similar to that of the Barito Estuary (in the southern part of Kalimantan) but lower than that of the Berau Estuary (in the northern part of Kalimantan), whereas the specific backscattering coefficient of Chl a is similar to that found in the Berau Estuary. This study contributes to the development of an operational method based on remote sensing data to map water constituent concentrations in the Mahakam Delta, as well as to enrich the information about the optical properties of Indonesian waters.

  4. Autonomous in situ measurements of seawater alkalinity.

    PubMed

    Spaulding, Reggie S; DeGrandpre, Michael D; Beck, James C; Hart, Robert D; Peterson, Brittany; De Carlo, Eric H; Drupp, Patrick S; Hammar, Terry R

    2014-08-19

    Total alkalinity (AT) is an important parameter for describing the marine inorganic carbon system and understanding the effects of atmospheric CO2 on the oceans. Measurements of AT are limited, however, because of the laborious process of collecting and analyzing samples. In this work we evaluate the performance of an autonomous instrument for high temporal resolution measurements of seawater AT. The Submersible Autonomous Moored Instrument for alkalinity (SAMI-alk) uses a novel tracer monitored titration method where a colorimetric pH indicator quantifies both pH and relative volumes of sample and titrant, circumventing the need for gravimetric or volumetric measurements. The SAMI-alk performance was validated in the laboratory and in situ during two field studies. Overall in situ accuracy was -2.2 ± 13.1 μmol kg(-1) (n = 86), on the basis of comparison to discrete samples. Precision on duplicate analyses of a carbonate standard was ±4.7 μmol kg(-1) (n = 22). This prototype instrument can measure in situ AT hourly for one month, limited by consumption of reagent and standard solutions.

  5. Autonomous in situ measurements of seawater alkalinity.

    PubMed

    Spaulding, Reggie S; DeGrandpre, Michael D; Beck, James C; Hart, Robert D; Peterson, Brittany; De Carlo, Eric H; Drupp, Patrick S; Hammar, Terry R

    2014-08-19

    Total alkalinity (AT) is an important parameter for describing the marine inorganic carbon system and understanding the effects of atmospheric CO2 on the oceans. Measurements of AT are limited, however, because of the laborious process of collecting and analyzing samples. In this work we evaluate the performance of an autonomous instrument for high temporal resolution measurements of seawater AT. The Submersible Autonomous Moored Instrument for alkalinity (SAMI-alk) uses a novel tracer monitored titration method where a colorimetric pH indicator quantifies both pH and relative volumes of sample and titrant, circumventing the need for gravimetric or volumetric measurements. The SAMI-alk performance was validated in the laboratory and in situ during two field studies. Overall in situ accuracy was -2.2 ± 13.1 μmol kg(-1) (n = 86), on the basis of comparison to discrete samples. Precision on duplicate analyses of a carbonate standard was ±4.7 μmol kg(-1) (n = 22). This prototype instrument can measure in situ AT hourly for one month, limited by consumption of reagent and standard solutions. PMID:25051401

  6. Comparison of in situ and columnar aerosol spectral measurements during TexAQS-GoMACCS 2006: testing parameterizations for estimating aerosol fine mode properties

    NASA Astrophysics Data System (ADS)

    Atkinson, D. B.; Massoli, P.; O'Neill, N. T.; Quinn, P. K.; Brooks, S.; Lefer, B.

    2009-08-01

    During the 2006 Texas Air Quality Study and Gulf of Mexico Atmospheric Composition and Climate Study (TexAQS-GoMACCS 2006), the optical, chemical and microphysical properties of atmospheric aerosols were measured on multiple mobile platforms and at ground based stations. In situ measurements of the aerosol light extinction coefficient (σep) were performed by two multi-wavelength cavity ring-down (CRD) instruments, one located on board the NOAA R/V Ronald H. Brown (RHB) and the other located at the University of Houston, Moody Tower (UHMT). An AERONET sunphotometer was also located at the UHMT to measure the columnar aerosol optical depth (AOD). The σep data were used to extract the extinction Ångström exponent (åep), a measure of the wavelength dependence of σep. There was general agreement between the åep (and to a lesser degree σep measurements by the two spatially separated CRD instruments during multi-day periods, suggesting a regional scale consistency of the sampled aerosols. Two spectral models are applied to the σep and AOD data to extract the fine mode fraction of extinction (η) and the fine mode effective radius (Reff f). These two parameters are robust measures of the fine mode contribution to total extinction and the fine mode size distribution respectively. The results of the analysis are compared to Reff f values extracted using AERONET V2 retrievals and calculated from in situ particle size measurements on the RHB and at UHMT. During a time period when fine mode aerosols dominated the extinction over a large area extending from Houston/Galveston Bay and out into the Gulf of Mexico, the various methods for obtaining Reff f agree qualitatively (showing the same temporal trend) and quantitatively (pooled standard deviation=28 nm).

  7. Comparison of in situ and columnar aerosol spectral measurements during TexAQS-GoMACCS 2006: testing parameterizations for estimating aerosol fine mode properties

    NASA Astrophysics Data System (ADS)

    Atkinson, D. B.; Massoli, P.; O'Neill, N. T.; Quinn, P. K.; Brooks, S. D.; Lefer, B.

    2010-01-01

    During the 2006 Texas Air Quality Study and Gulf of Mexico Atmospheric Composition and Climate Study (TexAQS-GoMACCS 2006), the optical, chemical and microphysical properties of atmospheric aerosols were measured on multiple mobile platforms and at ground based stations. In situ measurements of the aerosol light extinction coefficient (σep) were performed by two multi-wavelength cavity ring-down (CRD) instruments, one located on board the NOAA R/V Ronald H. Brown (RHB) and the other located at the University of Houston, Moody Tower (UHMT). An AERONET sunphotometer was also located at the UHMT to measure the columnar aerosol optical depth (AOD). The σep data were used to extract the extinction Ångström exponent (åep), a measure of the wavelength dependence of σep. There was general agreement between the åep (and to a lesser degree σep) measurements by the two spatially separated CRD instruments during multi-day periods, suggesting a regional scale consistency of the sampled aerosols. Two spectral models are applied to the σep and AOD data to extract the fine mode fraction of extinction (η) and the fine mode effective radius (Reff,f). These two parameters are robust measures of the fine mode contribution to total extinction and the fine mode size distribution, respectively. The results of the analysis are compared to Reff,f values extracted using AERONET V2 retrievals and calculated from in situ particle size measurements on the RHB and at UHMT. During a time period when fine mode aerosols dominated the extinction over a large area extending from Houston/Galveston Bay and out into the Gulf of Mexico, the various methods for obtaining Reff,f agree qualitatively (showing the same temporal trend) and quantitatively (pooled standard deviation = 28 nm).

  8. Instrumentation for the in-situ measurement of building envelopes

    SciTech Connect

    Grot, R.; Modera, M.; Fang, J.B.; Park, H.

    1985-01-01

    This paper discusses the types of instrumentation that can be used for the in-situ measurement of the thermal resistance of building components. Four types of instrumentation are described: noncontact spot radiometers, contact heat flow transducers, portable calorimeters, and a type of portable guarded hot plate device developed by Lawrence Berkeley Laboratories, called an envelope thermal testing unit. A brief description of each device is given along with a description of how the device is used to measure in-situ thermal properties of building components. A theoretical justification of the use of long-term averaging of the heat flow and temperature data for estimating the thermal resistance is also presented. The accuracy of each in-situ measurement method is accessed.

  9. Measure of Legionella penumophila activity in situ

    SciTech Connect

    Fliermans, C.B.; Soracco, R.J.; Pope, D.H.

    1981-01-01

    Detection of Legionella pneumophila by serogroup-specific fluorescent antibodies was combined with a tetrazolium dye (INT) to measure electron transport activity. The biological uptake and reduction of the INT dye was studied in pure cultures and in natural water samples with respect to temperature. Uptake was complete within 60 min. Controls inhibited with formaldehyde demonstrated little activity. Both the in vitro and in situ determinations suggested that the electron transport system of Legionella was active over a temperature range of 25 to 60/sup 0/C.

  10. Measure of Legionella pneumophila activity in situ

    SciTech Connect

    Fliermans, C.B.; Soracco, R.J.; Pope, D.H.

    1981-01-01

    Detection of Legionella pneumophila by serogroup-specific fluorescent antibodies was combined with a tetrazolium dye (INT) to measure electron transport activity. The biological uptake and reduction of the INT dye was studied in pure cultures and in natural water samples with respect to temperature. Uptake was complete within 60 minutes. Controls inhibited with formaldehyde demonstrated little activity. Both the in vitro and in situ determinations suggested that the electron transport system of Legionella was active over a temperature range of 25/sup 0/ to 60/sup 0/C.

  11. Study of thermal properties of the lunar regolith based on in situ temperature measurements and experiments on soil simulants

    NASA Technical Reports Server (NTRS)

    Langseth, M. G.; Horai, K. I.

    1973-01-01

    The experimental design and the development of a theory to interpret the experimental data from measurements of the thermal conductivity of lunar core samples. Measurements conducted while the lunar material is still in the core tube reduce the possibility of physical and chemical disturbances to the sample. The sample was heated externally by radiation at a known rate, the variation of temperature was measured at the surface of the core sample, and thermal conductivity was determined by comparing the observed temperature with the theoretically expected one.

  12. Density measurements and structural properties of liquid and amorphous metals under high pressure studied by in situ X-ray scattering (Invited)

    NASA Astrophysics Data System (ADS)

    Morard, G.; Garbarino, G.; Andrault, D.; Antonangeli, D.; Guignot, N.; Siebert, J.; Roberge, M.; Boulard, E.; Lincot, A.; Denoeud, A.; Petitgirard, S.

    2013-12-01

    Density determination for crystalline materials under high pressure and high temperature is straightforward using X-ray diffraction. For liquid and amorphous materials, it is more complicated due to the absence of long-range order. Different high pressure techniques have been developed: in-situ X-ray absorption 1-4 or ex-situ sink/float method 5-8. However, these techniques suffer several limitations, such as the limited pressure range or the long exposure time required. We have implemented an in situ X-ray diffraction analysis method suitable for the determination of Pressure-Volume-Temperature equations of state (P-V-T EoS) in the critical case of liquid and amorphous materials over an extended thermodynamic range (T>2000 K and P> 40 GPa). This method is versatile, it can be applied to data obtained using various angle-dispersive X-ray diffraction high-pressure apparatus and, contrary to in situ X-ray absorption techniques, is independent from the sample geometry. Further advantage is the fast data acquisition (between 10 to 300 seconds integration time). Information on macroscopic bulk properties (density) and local atomic arrangement (pair distribution function g(r)) can be gathered in parallel. To illustrate the method, we present studies on liquid Fe-S alloys in Paris Edinburgh press and in laser-heated diamond anvil cell, and measurements on Ce glass in diamond anvil cell at room temperature. References 1 G. Shen, N. Sata, M. Newville et al., App. Phys. Lett. 81 (8), 1411 (2002). 2 C. Sanloup, F. Guyot, P. Gillet et al., Geophys. Res. Lett. 27 (6), 811 (2000). 3 Y. Katayama, K. Tsuji, O. Shimomura et al., J. Synch. Rad. 5, 1023 (1998). 4 T. Sato and N. Funamori, Phys. Rev. Lett. 101, 255502 (2008). 5 R. Knoche and R. W. Luth, Chem. Geol. 128, 229 (1996). 6 P.S. Balog, R.A. Secco, D.C. Rubie et al., J. Geophys. Res. 108 (B2), 2124 (2003). 7 C. B. Agee and D. Walker, J. Geophys. Res. 93 (B4), 3437 (1988). 8 E. Ohtani, A. Suzuki, and T. Kato, Proc. Jpn. Acad

  13. In-situ Measurements of Geotechnical and Geo-Acoustic Seabed Properties Using a Free Fall Cone Penetrometer

    NASA Astrophysics Data System (ADS)

    Osler, J.; Trevorrow, M.; Furlong, A.; Christian, H.

    2001-12-01

    The FFCPT is a free fall probe that has been developed to measure acceleration and dynamic sediment porewater pressure as a function of depth of penetration into the seafloor. It also records hydrostatic pressure and optical backscatter in the water column, for mudline detection capability. This combination of sensors permits the direct application of geotechnical analysis methods and parametric-based correlations already long established in engineering practice. The FFCPT provides two independent means of calculating the undrained shear strength, as well as other engineering variables that are used in sediment textural classification. Specifically, there are accepted empirical relationships between the dynamic pore pressure parameter, the normalized dynamic penetration resistance and sediment grain size characteristics. The probe has a modular design allowing additional sensor payloads to be integrated. The first module to be developed measures resistivity, as a means to determine sediment bulk density. Experimental results from the New Jersey Strataform area and the Scotian Shelf will be presented and compared with measurements using a Seabed Terminal Impact Newton Gradiometer (STING) and an eXpendable Bottom Penetrometer (XBP).

  14. In situ measurement of the biogeochemical properties of Southern Ocean mesoscale eddies in the Southwest Indian Ocean, April 2014

    NASA Astrophysics Data System (ADS)

    de Villiers, S.; Siswana, K.; Vena, K.

    2015-12-01

    Several open-ocean mesoscale features - a "young" warm-core (anti-cyclonic) eddy at 52° S, an "older" warm-core eddy at 57.5° S and an adjacent cold-core (cyclonic) eddy at 56° S - were surveyed during a R/V S.A. Agulhas II cruise in April 2014. The main aim of the survey was to obtain hydrographical and biogeochemical profile data for contrasting open-ocean eddies in the Southern Ocean, which will be suitable for comparative study and modelling of their heat, salt and nutrient characteristics, and the changes that occur in these properties as warm-core eddies migrate from the polar front southwards. The major result is that the older warm-core eddy at 57.5° S is, at its core, 2.7 °C colder than a younger eddy at 52° S, while its dissolved silicate levels are almost 500 % higher and accompanied by chlorophyll a levels that are more than 200 % higher than that in the younger eddy. A total of 18 CTD stations were occupied in a sector south of the Southwest Indian Ridge, along three transects crossing several mesoscale features identified from satellite altimetry data prior to the cruise. The CTD data, as well as chlorophyll a and dissolved nutrient data (for NO3-, NO2-, PO43- and SiO2), have been processed, quality controlled and made available via the PANGAEA Data Archiving and Publication database at doi:10.1594/PANGAEA.848875.

  15. In situ measurement of the biogeochemical properties of Southern Ocean mesoscale eddies in the Southwest Indian Ocean, April 2014

    NASA Astrophysics Data System (ADS)

    de Villiers, S.; Siswana, K.; Vena, K.

    2015-10-01

    Several open-ocean mesoscale features, a "young" warm-core (anti-cyclonic) eddy at 52° S, an "older" warm-core eddy at 57.5° S, as well as an adjacent cold-core (cyclonic) eddy at 56° S, were surveyed during a M/V S.A. Agulhas II cruise in April 2014. The main aim of the survey was to obtain hydrographical and biogeochemical profile data for contrasting open-ocean eddies in the Southern Ocean, that will be suitable for comparison and modelling of their heat, salt and nutrient characteristics, and the changes that occur in these properties as warm-core eddies migrate from the polar front southwards into the Southern Ocean. Results show that the older warm-core eddy at 57.5° S is, at its core, 2.7 °C colder than a younger eddy at 52° S, while its dissolved silicate levels are almost 500 % higher and accompanied by chl a levels that are more than 200 % higher than that in the younger eddy. A total of 18 CTD stations were occupied in a sector south of the Southwest Indian Ridge, along three transects crossing several mesoscale features identified from satellite altimetry data prior to the cruise. The CTD data, as well as chl a and dissolved nutrient data (for NO3-, NO2-, PO43- and SiO2) have been processed, quality-controlled and made available via the PANGAEA Data Archiving and Publication database at doi:10.1594/PANGAEA.848875.

  16. Property development for biaxial drawing of ethylene-tetrafluoroehtylene copolymer films and resultant fractural behavior analyzed by in situ X-ray measurements.

    PubMed

    Uehara, Hiroki; Ono, Yasunori; Kakiage, Masaki; Sakamura, Takumi; Masunaga, Hiroyasu; Yukawa, Yasumasa; Higuchi, Yoshiaki; Kamiya, Hiroki; Yamanobe, Takeshi

    2015-03-19

    The property development of the ethylene-tetrafluoroethylene copolymer (ETFE) membrane induced by simultaneous biaxial drawing was investigated. Commonly, tensile strength can be increased by drawing; conversely, tear resistance decreases. In this study, the balance between tensile strength and tear resistance for the resultant ETFE membrane was optimized achieved by a combination of lamination of low molecular weight (LMW) and high molecular weight (HMW) layers and subsequent biaxial drawing. The structural factor determining tear resistance of these biaxially drawn membranes was determined based on in situ small-angle X-ray scattering (SAXS) measurement during tensile deformation simulating tearing tests. Lozenge shaped scattering, which indicated inclined lamellae, was observed during such tensile deformation of the resultant membranes. Remarkably, this inclined lamellar structure was observed for the pure LMW membrane; however, it also appeared at the interface between LMW and HMW layers within biaxially drawn membranes. For the membrane exhibiting the highest tearing strength, the fraction of such inclined lamella increased up to the critical strain corresponding to the actual sample breaking. These results confirm that the inclined lamellar structure absorbed strain during membrane tearing. PMID:25697812

  17. Application of cavity ring-down spectroscopy for in situ, real-time measurements of properties of oceanographic interest in the surface ocean

    NASA Astrophysics Data System (ADS)

    Huang, Kuan; Ma, Jian; Winkler, Renato; Dennis, Kate

    2015-04-01

    In situ, real-time measurements of chemical properties, e.g., dissolved CO2 and its carbon isotopic compositions, dissolved inorganic carbon, water isotopes, etc., are highly desired for understanding various physical and biogeochemical processes in the surface ocean. Due to its high sensitivity, stability and portability, cavity ring-down spectroscopy (CRDS) has been increasingly used as a core technique for shipboard systems that automatically measure properties of oceanographic interest at high spatial-temporal resolution. These systems typically require front-end components that convert the sample into a continuous gas flow that can be continuously sampled by the CRDS. Here, we review the progress in the development of CRDS-based systems for shipboard, high-frequency measurements of various properties in the surface ocean, including pCO2, δ13C-CO2, pCH4, δ13C-CH4, and water isotopes. In most systems, gas extraction devices are keys to the sample preparation units that are coupled with the CRDS analyzers. In our present work, we summarize the major gas extraction techniques used in these methods (e.g. the showerhead-type equilibration, the bubbling equilibration, the high-porosity membrane contactor extraction, the expanded polytetrafluoroethylene-based extraction, etc.), present examples how these techniques are coupled with CRDS analyzers, and evaluate the major factors that determine the overall performance (precision, accuracy, response time, etc.) of the systems. Based on the working principles and field data generated by these systems, we were able to identify the major factors that affect the system performance, including the efficiency (completeness) of gas extraction, magnitude and stability of isotopic fractionation during the gas extraction, internal volume of the system (e.g., the volume of the equilibration chamber and that of the CRDS cavity) and the carrier gas flow rate. Finally, we make recommendations, for each type of system, the optimal

  18. IN SITU ELLIPSOMETRY FOR SHOCK COMPRESSION MEASUREMENTS

    SciTech Connect

    Bakshi, L.; Eliezer, S.; Appelbaum, G.; Nissim, N.; Perelmutter, L.; Mond, M.

    2009-12-28

    Knowledge about the optical properties of materials at high pressure and high temperature is needed for EOS research. Ellipsometry measures the change in the polarization of a probe beam reflected from a surface. From the change in polarization, the real and imaginary parts of the time dependent complex index of refraction can be extracted. From the measured optical properties, fundamental physical properties of the material, such as emissivity, phase transitions, and electrical conductivity can be extracted. A dynamic ellipsometry measurement system with nanosecond resolution was built in order to measure all four stocks parameters. Gas gun was used to accelerate the impact flyer. Our experiments concentrated on the optical properties of 1020 steel targets with impact pressure range of 40-250 kbar. Although there are intrinsic difficulties with dynamic ellipsometric measurements, distinct changes were observed for 1020 steel under shock compression larger than 130 kbar, the alpha->epsilon phase transition.

  19. In Situ Measurements of Meteoric Ions

    NASA Technical Reports Server (NTRS)

    Grebowsky, Joseph M.; Aiken, Arthur C.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Extraterrestrial material is the source of metal ions in the Earth's atmosphere, Each year approx. 10(exp 8) kg of material is intercepted by the Earth. The origin of this material is predominantly solar orbiting interplanetary debris from comets or asteroids that crosses the Earth's orbit. It contains a very small amount of interstellar material. On occasion the Earth passes through enhanced amounts of debris associated with the orbit of a decaying comet. This leads to enhanced meteor shower displays for up to several days. The number flux of shower material is typically several times the average sporadic background influx of material. Meteoric material is some of the earliest material formed in the solar system. By studying the relative elemental abundances of atmospheric metal ions, information can be gained on the chemical composition of cometary debris and the chemical makeup of the early solar system. Using in situ sampling with rocket-borne ion mass spectrometers; there have been approximately 50 flights that made measurements of the metal ion abundances at attitudes between 80 and 130 km. It is this altitude range where incoming meteoric particles am ablated, the larger ones giving rise to visible meteor. displays. In several rocket measurements isotopic ratios of different atomic ion mass components and metal molecular ion concentrations have been determined and used to identify unambiguously the measured species and to investigate the processes controlling the metal ion distributions The composition of the Earth's ionosphere was first sampled by an ion mass spectrometer flown an a rocket in 1956. In 1958 a rocket-borne ion spectrometer identified, fbr the first time, a layer of metal ions near 95 km. These data were interpreted as evidence of an extraterrestrial rather than a terrestrial source. Istomin predicted: "It seems probable that with some improvement in the method that analysis of the ion composition in the E-region may be used for determining

  20. In-Situ Dust Measurements in Jupiter's Gossamer Rings

    NASA Astrophysics Data System (ADS)

    Krueger, H.; Gruen, E.; Hamilton, D. P.

    2003-04-01

    Jupiter's ring system -- the archetype of ethereal ring systems -- consists of at least three components: the main ring, the vertically extended halo and the gossamer ring(s). The small moonlets Thebe and Amalthea orbit Jupiter within the gossamer ring region and structure in the intensity obtained from imaging observations indicates that these moons are the dominant sources of the gossamer ring material. The current picture implies that particles ejected from a source moon evolve inward under the Poynting-Robertson drag. Beyond Thebe's orbit, a very faint outward extension of the gossamer ring has also been observed which is not yet explained. Typical grain radii derived from optical imaging are a few micrometers. In November 2002 the Galileo spacecraft traversed the gossamer ring for the first time and had a close flyby at Amalthea. With the in-situ dust detector on board, dust measurements were collected throughout the gossamer ring and close to Amalthea. Several hundred impacts of dust grains were recorded and the data sets (impact charges, rise times, impact directions, etc.) of about 70 impacts were transmitted to Earth. In-situ dust measurements provide information about the physical properties of the dust environment not accessible with imaging techniques. They directly provide dust spatial densities along the spacecraft trajectory as well as grain sizes and impact speeds. This allows to test and refine current models of ring particle dynamics (see D. P. Hamilton et al., this conference). In particular, the direct measurement of grain sizes and dust spatial density in different regions of the gossamer ring allow to better constrain the forces dominating the grains' dynamics. The Galileo measurements in Jupiter's gossamer ring pave the way towards the in-situ dust measurements with Cassini in Saturn's E ring beginning in 2004.

  1. Galileo in-situ dust measurements in Jupiter's Gossamer Rings

    NASA Astrophysics Data System (ADS)

    Krueger, H.; Grün, E.; Hamilton, D. P.

    2003-05-01

    Jupiter's ring system -- the archetype of ethereal ring systems -- consists of at least three components: the main ring, the vertically extended halo and the gossamer ring(s). The small moonlets Thebe and Amalthea orbit Jupiter within the gossamer ring region and structure in the intensity obtained from imaging observations indicates that these moons are the dominant sources of the gossamer ring material. The current picture implies that particles ejected from a source moon evolve inward under the Poynting-Robertson drag. Beyond Thebe's orbit, a very faint outward extension of the gossamer ring has also been observed which is not yet explained. Typical grain radii derived from optical imaging are a few micrometers. In November 2002 the Galileo spacecraft traversed the gossamer ring for the first time and had a close flyby at Amalthea. With the in-situ dust detector on board, dust measurements were collected throughout the gossamer ring and close to Amalthea. Several hundred impacts of dust grains were recorded and the data sets (impact charges, rise times, impact directions, etc.) of about 90 impacts were transmitted to Earth. In-situ dust measurements provide information about the physical properties of the dust environment not accessible with imaging techniques. They directly provide dust spatial densities along the spacecraft trajectory as well as grain sizes and impact speeds. This allows to test and refine current models of ring particle dynamics (see D. P. Hamilton et al., this conference). In particular, the direct measurement of grain sizes and dust spatial density in different regions of the gossamer ring allow to better constrain the forces dominating the grains' dynamics. The Galileo measurements in Jupiter's gossamer ring pave the way towards the in-situ dust measurements with Cassini in Saturn's E ring beginning in 2004.

  2. In situ measurement requirements for a solar probe

    NASA Astrophysics Data System (ADS)

    Roberts, D. A.; Gosling, J. T.

    1997-01-01

    We present the rationale and in situ measurement requirements for a near-Sun mission intended to answer the central questions of the heating of the corona and the acceleration of the solar wind. These conclusions are based on panel discussions and presentations at the Marlboro workshop. We have in mind not a ``minimum'' mission [1], but rather one that is constrained but feasible within the current mass and telemetry rate restrictions. To distinguish between thermal, wave-driven, and microflare-driven models, the measurements must determine wave levels in a broad range of frequencies, resolve fine-scale structures, find the energetic particle content and its variations, and determine the bulk properties of a few species with detailed distributions for at least electrons and protons. We find that the in situ measurements needed to answer the main questions are similar to those proposed previously [4] (magnetic field, plasma, high-energy particles, and plasma wave instruments) but without neutron and dust experiments. Telemetry and mass constraints will be significant but should not be prohibitive.

  3. In situ measurements of aerosol optical properties and number size distributions in a coastal region of Norway during the summer of 2008

    NASA Astrophysics Data System (ADS)

    Mogo, S.; Cachorro, V. E.; Lopez, J. F.; Montilla, E.; Torres, B.; Rodríguez, E.; Bennouna, Y.; de Frutos, A. M.

    2012-07-01

    In situ measurements of aerosol optical properties and particle size distributions were made in the summer of 2008 at the ALOMAR station facility (69°16' N, 16°00' E), located in a rural site in the north of the island of Andøya (Vesterålen archipelago), approximately 300 km north of the Arctic Circle. The extended three-month campaign was part of the POLARCAT Project (Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols, and Transport) of the International Polar Year (IPY-2007-2008). Our goal was to characterize the aerosols of this sub-Arctic area, which are frequently transported to the Arctic region. Data from 13 June to 26 August 2008 were available and the statistical data for all instruments were calculated based on the hourly averages. The overall data coverage was approximately 72%. The hourly mean values of the light-scattering coefficient, σs, and the light-absorption coefficient, σa, at 550 nm were 5.41 Mm-1 (StD = 3.55 Mm-1) and 0.40 Mm-1 (StD = 0.27 Mm-1), respectively. The scattering/absorption Ångström exponents, αs,a, were used in a detailed analysis of the variations of the spectral shape of σs,a. While αs indicates the presence of two particle sizes corresponding to two types of aerosols, αa indicates only one type of absorbing aerosol particle. αa values greater than 1 were not observed. The single-scattering albedo, ω0, ranged from 0.62 to 0.99 (mean = 0.91, StD = 0.05), and the relationships between this parameter and the absorption/scattering coefficients and the Ångström exponents are presented. Any absorption value may lead to the lowest values of ω0, whereas only the lowest scattering values were observed in the lowest range of ω0. For a given absorption value, lower ω0 were observed for smaller αs. The submicrometer, micrometer and total concentrations of the particles presented hourly mean values of 1277 cm-3 (StD = 1563 cm-3), 1 cm-3 (StD = 1 cm-3) and 2463 cm-3

  4. Microphysical properties of synoptic-scale polar stratospheric clouds: in situ measurements of unexpectedly large HNO3-containing particles in the Arctic vortex

    NASA Astrophysics Data System (ADS)

    Molleker, S.; Borrmann, S.; Schlager, H.; Luo, B.; Frey, W.; Klingebiel, M.; Weigel, R.; Ebert, M.; Mitev, V.; Matthey, R.; Woiwode, W.; Oelhaf, H.; Dörnbrack, A.; Stratmann, G.; Grooß, J.-U.; Günther, G.; Vogel, B.; Müller, R.; Krämer, M.; Meyer, J.; Cairo, F.

    2014-10-01

    In January 2010 and December 2011, synoptic-scale polar stratospheric cloud (PSC) fields were probed during seven flights of the high-altitude research aircraft M-55 Geophysica within the RECONCILE (Reconciliation of essential process parameters for an enhanced predictability of Arctic stratospheric ozone loss and its climate interaction) and the ESSenCe (ESSenCe: ESA Sounder Campaign) projects. Particle size distributions in a diameter range between 0.46 and 40μm were recorded by four different optical in situ instruments. Three of these particle instruments are based on the detection of forward-scattered light by single particles. The fourth instrument is a grayscale optical array imaging probe. Optical particle diameters of up to 35μm were detected with particle number densities and total particle volumes exceeding previous Arctic measurements. Also, gas-phase and particle-bound NOy was measured, as well as water vapor concentrations. The optical characteristics of the clouds were measured by the remote sensing lidar MAL (Miniature Aerosol Lidar) and by the in situ backscatter sonde MAS (Multiwavelength Aerosol Scatterometer), showing the synoptic scale of the encountered PSCs. The particle mode below 2μm in size diameter has been identified as supercooled ternary solution (STS) droplets. The PSC particles in the size range above 2μm in diameter are considered to consist of nitric acid hydrates, and the particles' high HNO3 content was confirmed by the NOy instrument. Assuming a particle composition of nitric acid trihydrate (NAT), the optically measured size distributions result in particle-phase HNO3 mixing ratios exceeding available stratospheric values. Therefore the measurement uncertainties concerning probable overestimations of measured particle sizes and volumes are discussed in detail. We hypothesize that either a strong asphericity or an alternate particle composition (e.g., water ice coated with NAT) could explain our observations. In particular

  5. In situ measurement of conductivity during nanocomposite film deposition

    NASA Astrophysics Data System (ADS)

    Blattmann, Christoph O.; Pratsinis, Sotiris E.

    2016-05-01

    Flexible and electrically conductive nanocomposite films are essential for small, portable and even implantable electronic devices. Typically, such film synthesis and conductivity measurement are carried out sequentially. As a result, optimization of filler loading and size/morphology characteristics with respect to film conductivity is rather tedious and costly. Here, freshly-made Ag nanoparticles (nanosilver) are made by scalable flame aerosol technology and directly deposited onto polymeric (polystyrene and poly(methyl methacrylate)) films during which the resistance of the resulting nanocomposite is measured in situ. The formation and gas-phase growth of such flame-made nanosilver, just before incorporation onto the polymer film, is measured by thermophoretic sampling and microscopy. Monitoring the nanocomposite resistance in situ reveals the onset of conductive network formation by the deposited nanosilver growth and sinternecking. The in situ measurement is much faster and more accurate than conventional ex situ four-point resistance measurements since an electrically percolating network is detected upon its formation by the in situ technique. Nevertheless, general resistance trends with respect to filler loading and host polymer composition are consistent for both in situ and ex situ measurements. The time lag for the onset of a conductive network (i.e., percolation) depends linearly on the glass transition temperature (Tg) of the host polymer. This is attributed to the increased nanoparticle-polymer interaction with decreasing Tg. Proper selection of the host polymer in combination with in situ resistance monitoring therefore enable the optimal preparation of conductive nanocomposite films.

  6. In-situ permittivity measurements using ring resonators

    NASA Astrophysics Data System (ADS)

    Mazzaro, Gregory J.

    2012-06-01

    Proper development of ground-penetrating radar (GPR) technology requires a unique understanding of the electromagnetic (EM) properties of targets and background media. Thus, electromagnetic characterization of targets and backgrounds is fundamental to the success or failure of UWB GPR as a threat detection technique. In many cases, threats are buried in soil. Soil properties directly affect the radar signature of targets and determine the depth at which they can be detected by radar. One such property is permittivity. A portable system recently developed at the U.S. Army Research Laboratory measures permittivity in-situ with minimal disturbance of the dielectric sample. The measurement technique uses ring resonators. Design equations and physical dimensions are presented for fabricating resonators at frequencies between 600 MHz and 2 GHz. Only a handheld vector network analyzer, coaxial cabling, and the ring resonators are necessary for each measurement. Lookup curves generated in simulation are referenced to calculate the complex permittivity of the sample. The permittivity measurement is explained step-by-step, and data is presented for samples of soils from Ft. Irwin, California and Yuma, Arizona.

  7. In-Situ Measurements of Graphene Mechanics During Annealing

    NASA Astrophysics Data System (ADS)

    Hui, Aaron; de Alba, Roberto; Sebastian, Abhilash; Parpia, Jeevak

    Graphene shows great potential as a material for a new generation of mechanical nanodevices. However, current methodologies used for fabricating graphene structures involve polymer resists for transfer and patterning, which degrades mechanical performance. To improve surface quality, high current or high temperature annealing of graphene is commonly employed. Previous studies of graphene mechanics have focused on performance after annealing or temperature-dependent behavior from 4K-300K. Here we present real-time, in-situ measurements of graphene mechanical resonance during high temperature annealing from 300K-600K. Upon heating, reversible changes in mechanical frequency are indicative of graphene thermal contraction. Discontinuous and irreversible changes are also seen, corresponding to graphene slipping and mass desorption. Both reversible and irreversible changes in quality factor are also observed. Characterizing the effects of annealing on the structural properties of graphene will enable more precise engineering for particular applications, such as mass sensing.

  8. In-situ measurements of velocity structure within turbidity currents

    USGS Publications Warehouse

    Xu, J. P.; Noble, M.A.; Rosenfeld, L.K.

    2004-01-01

    Turbidity currents are thought to be the main mechanism to move ???500,000 m3 of sediments annually from the head of the Monterey Submarine Canyon to the deep-sea fan. Indirect evidence has shown frequent occurrences of such turbidity currents in the canyon, but the dynamic properties of the turbidity currents such as maximum speed, duration, and dimensions are still unknown. Here we present the first-ever in-situ measurements of velocity profiles of four turbidity currents whose maximum along-canyon velocity reached 190 cm/s. Two turbidity currents coincided with storms that produced the highest swells and the biggest stream flows during the year-long deployment. Copyright 2004 by the American Geophysical Union.

  9. Comparison of in situ and satellite-derived cloud properties during SUCCESS

    NASA Astrophysics Data System (ADS)

    Young, David F.; Minnis, Patrick; Baumgardner, Darrel; Gerber, H.

    The validation of cloud microphysical properties derived from satellite data with in situ observations is generally difficult due to the spatial and temporal variability of observed clouds. Two missions during SUCCESS concentrated on orographic wave clouds that exhibited relative spatial and temporal homogeneity. A comparison has been made of effective ice particle diameters derived from multispectral satellite data with in situ measurements from the MASP and PVM instruments aboard the DC-8 aircraft. For both days, the satellite-derived effective diameters fall well within the bounds of the in situ data.

  10. Galileo In-Situ Dust Measurements in Jupiter's Gossamer Rings

    NASA Astrophysics Data System (ADS)

    Krueger, H.; Hamilton, D. P.; Gruen, E.

    Jupiter's ring system consists of at least three components: the inner main ring, the vertically extended halo and the gossamer ring(s) further out. The small moons Thebe and Amalthea orbit Jupiter within the gossamer ring and are believed to be the sources of gossamer ring material. A very faint ring extension has also been observed beyond Thebe's orbit. On 5 November 2002 the Galileo spacecraft traversed Jupiter's gossamer ring system for the first time. High-resolution dust data were obtained with the dust detector on board down to 2.33 R_J , i.e. well inside Amalthea's orbit. A second ring passage occurred on 21 September 2003, a few hours before Galileo impacted Jupiter. This time, dust data were successfully received down to Amalthea's orbit at 2.5 R_J , however, with much reduced time-resolution. Several thousand dust impacts were counted during both ring passages, and the full data sets (impact charges, rise times, impact directions, etc.) of about 90 dust impacts were transmitted to Earth. In-situ dust measurements provide information about the physical properties of the dust environment not accessible with imaging techniques. They directly measure dust spatial densities along the spacecraft trajectory as well as grain sizes and impact speeds. Our as yet preliminary analysis %of the gossamer ring data implies particle sizes in the sub-micron and micron range. The size distribution -- increasing towards smaller particles -- is similar in the Thebe ring and the ring's outer extension, whereas in the Amalthea ring it is steeper. Dust number densities are about 104 - 106 km-3 . Our dust data allow for the first time to compare in-situ measurements with the results optical obtained from the inversion of optical images. It appears that small sub-micron grains dominate the number density whereas larger particles with at least a few micron radii contribute most to the optical depth. The dust density shows previously unrecognised fine-structure in the ring between

  11. Microphysical properties of synoptic scale polar stratospheric clouds: in situ measurements of unexpectedly large HNO3 containing particles in the Arctic vortex

    NASA Astrophysics Data System (ADS)

    Molleker, S.; Borrmann, S.; Schlager, H.; Luo, B.; Frey, W.; Klingebiel, M.; Weigel, R.; Ebert, M.; Mitev, V.; Matthey, R.; Woiwode, W.; Oelhaf, H.; Dörnbrack, A.; Stratmann, G.; Grooß, J.-U.; Günther, G.; Vogel, B.; Müller, R.; Krämer, M.; Meyer, J.; Cairo, F.

    2014-05-01

    In January 2010 and December 2011 synoptic scale PSC fields were probed during seven flights of the high altitude research aircraft M-55 Geophysica within the RECONCILE (Reconciliation of essential process parameters for an enhanced predictability of Arctic stratospheric ozone loss and its climate interaction.) and the ESSenCe (ESSenCe: ESA Sounder Campaign) projects. Particle size distributions in a diameter range between 0.46 μm and 40 μm were recorded simultaneously by up to four different optical in situ instruments. Three of these particle instruments are based on the detection of forward scattered light by single particles. The fourth instrument is a grey scale optical array imaging probe. Optical particle diameters of up to 35 μm were detected with particle number densities and total particle volumes exceeding previous Arctic measurements. Also, gas phase and particle bound NOy were measured, as well as water vapor concentrations, and other variables. Two remote sensing particle instruments, the Miniature Aerosol Lidar (MAL) and the backscatter sonde (MAS, Multiwavelenght Aerosol Scatterometer) showed the synoptic scale of the encountered PSCs. The particle mode below 2 μm in size diameter has been identified as supercooled ternary solution droplets (STS). The PSC particles in the size range above 2 μm in diameter are considered to consist of nitric acid hydrates or ice, and the particles' high HNO3 content was confirmed by the NOy instrument. Assuming a particle composition of nitric acid trihydrate (NAT), the optically measured size distributions result in particle-phase HNO3 mixing ratios exceeding available stratospheric values. In particular, with respect to the denitrification by sedimentation of large HNO3-contaning particles, generally considered as NAT, our new measurements raise questions concerning composition, shape and nucleation pathways. Measurement uncertainties are discussed concerning probable overestimations of measured particle sizes

  12. In-situ measurements of lunar heat flow

    NASA Technical Reports Server (NTRS)

    Langseth, M. G.; Keihm, S. J.

    1974-01-01

    During the Apollo program two successful heat flow measurements were made in situ on the lunar surface. At the Apollo 15 site a value of 0.0000031 watts/sqcm was measured and at the Apollo 17 site a value of 0.0000022 watts/sqcm was determined. Both measurements have uncertainty limits of + or - 20% and have been corrected for perturbing topographic effects. The apparent difference between the observations may correlate with observed variations in the surface abundance of thorium. Comparison with earlier determinations of heat flow, using the microwave emission spectrum from the moon, gives support to the high gradients and heat flows observed in situ.

  13. In-situ measurements of lunar heat flow

    NASA Technical Reports Server (NTRS)

    Langseth, M. B.; Keihm, S. J.

    1977-01-01

    During the Apollo program two successful heat flow measurements were made in situ on the lunar surface. At the Apollo 15 site a value of .0000031 W/sq cm was measured, and at the Apollo 17 site a value of .0000022 W/sq cm was determined. Both measurements have uncertainty limits of + or - 20 percent and have been corrected for perturbing topographic effects. The apparent difference between the observations may correlate with observed variations in the surface abundance of thorium. Comparison with earlier determinations of heat flow, using the microwave emission spectrum from the moon, gives support to the high gradients and heat flows observed in situ.

  14. Subsurface In situ elemental composition measurements with PING

    NASA Astrophysics Data System (ADS)

    Parsons, A.; McClanahan, T.; Bodnarik, J.; Evans, L.; Nowicki, S.; Schweitzer, J.; Starr, R.

    This paper describes the Probing In situ with Neutron and Gamma rays (PING) instrument, that can measure the subsurface elemental composition in situ for any rocky body in the solar system without the need for digging into the surface. PING consists of a Pulsed Neutron Generator (PNG), a gamma ray spectrometer and neutron detectors. Subsurface elements are stimulated by high-energy neutrons to emit gamma rays at characteristic energies. This paper will show how the detection of these gamma rays results in a measurement of elemental composition. Examples of the basalt to granite ratios for aluminum and silicon abundance are provided.

  15. Subsurface In Situ Elemental Composition Measurements with PING

    NASA Technical Reports Server (NTRS)

    Parsons, Ann; McClanahan, Timothy; Bodnarik, Julia; Evans, Larry; Nowicki, Suzanne; Schweitzer, Jeffrey; Starr, Richard

    2013-01-01

    This paper describes the Probing In situ with Neutron and Gamma rays (PING) instrument, that can measure the subsurface elemental composition in situ for any rocky body in the solar system without the need for digging into the surface. PING consists of a Pulsed Neutron Generator (PNG), a gamma ray spectrometer and neutron detectors. Subsurface elements are stimulated by high-energy neutrons to emit gamma rays at characteristic energies. This paper will show how the detection of these gamma rays results in a measurement of elemental composition. Examples of the basalt to granite ratios for aluminum and silicon abundance are provided.

  16. High Stress Consolidation, Ultrasonic, and Permeability Measurements: Constraints on Physical Properties and In Situ Stress along the Costa Rica Subduction Plate Interface

    NASA Astrophysics Data System (ADS)

    Winner, A.; Saffer, D. M.; Valdez, R. D.

    2014-12-01

    Sediment permeability and consolidation behavior are key parameters in governing the drainage state and thus potential for excess pore fluid pressure in subduction zones. Elevated pore pressure, in turn, is one important control on the strength and sliding behavior of faults. Along many subduction margins, evidence of elevated, near-lithostatic, in situ pore pressure comes from high seismic reflectivity, low P-wave velocity (Vp), and high Vp/Vs ratios. This inference is broadly supported by numerical modeling studies that indicate elevated pore pressures are likely given high rates of burial and tectonic loading, combined with the low permeability of marine mudstones. Here, we report on a series of high-stress consolidation experiments on sediment core samples from the incoming Cocos plate obtained as part of Integrated Ocean Drilling Program (IODP) Expedition 344. Our experiments were designed to measure the consolidation behavior, permeability, and P-wave velocity of the incoming sediments over a range of confining stresses from .5 to 90 MPa. We explore a range of paths,including isostatic loading (σ1=σ2=σ3), K0 consolidation, in which the ratio of σ3/σ1 is maintained at ~0.6, and the trixial loading paths designed to maintain a near critical-state failure condition. In our tests, load is increased in a series of steps. After equilibration at each step, we conduct constant head permeability tests, and measure P-wave velocities in a "time of flight" mode. Initial results from isostatic loading tests on hemipelagic mudstone samples from 34 mbsf document consolidation and permeability-porosity trends, in which porosity decreases from 69% to 54% as stress in increased from .5 MPa to 15 MPa, and permeability decreases from 8.1 X 10-18 m2 at 1 MPa to 1.1 X 10-19 m2 at 15 MPa. P-wave velocity increases by 486-568 km/s over this effective stress range. Ultimately, data from our experiments will provide a robust basis for quantifying fluid content and pressure from

  17. Combined aerosol in-situ measurements during the SALTRACE field experiment for the investigation of Saharan mineral dust microphysical and CCN properties and their spatial-temporal evolution during trans-Atlantic long-range transport

    NASA Astrophysics Data System (ADS)

    Walser, Adrian; Dollner, Maximilian; Sauer, Daniel; Weinzierl, Bernadett

    2015-04-01

    The Saharan Aerosol Long-range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE) was a field experiment conducted in June/July 2013, which aimed to investigate the transport and modification of Saharan mineral dust from the Sahara across the Atlantic Ocean to the Caribbean. In addition to ground-based measurements and satellite remote sensing, the DLR Falcon research aircraft was equipped with a number of aerosol in-situ instruments to gain direct information on the properties of airborne aerosol such as size distributions, microphysical, optical and cloud-condensation nuclei (CCN) properties. For the first time, several outbreaks of Saharan dust were probed with the same airborne instrumentation on both sides of the Atlantic. During transport, various processes may take place that modify the aerosol composition. Dry and wet deposition lead to a size-dependent aerosol removal. In case of wet deposition, the removal additionally depends on the particle's ability to act as CCN. Processes in the aqueous phase in subsequently re-evaporating cloud droplets can further alter microphysical and CCN properties of re-released particles. All resulting changes in the size distribution and particle properties impact the radiative feedback and CCN activity of the aged aerosol. This study aims to use combined airborne in-situ measurements to retrieve and compare vertically resolved aerosol size distributions, microphysical and CCN properties for both, short-range transported Saharan dust in the Cape Verde region and long-range transported dust in the Caribbean. We use this data to investigate the influence of long-range transport and associated processes on those properties. We will present vertical profiles of size-resolved aerosol concentrations and volatile fractions as well as CCN activated fractions and draw conclusions for aerosol mixing state, CCN activation diameters and particle hygroscopicities. We will discuss differences in vertical profiles and

  18. Development of an in-situ structure/photo-absorption coincident measurement system for precise structure-optical property relationship research at SPring-8

    NASA Astrophysics Data System (ADS)

    Kim, Jungeun; Kato, Kenichi; Moritomo, Yutaka; Takata, Masaki

    2010-06-01

    We have developed the structure and optical property coincident measurement system equipped with the photo-absorption system to the Large Debye-Scherrer Camera at BL44B2 of the SPring-8. Both photo-absorption detecting systems, the Si pin-photo diode for a 532 nm CW laser and the absorption spectrum covered the range of UV-IR (200˜1400 nm) for a white beam, are adopted. In order to verify the coincident measurement system, the X-ray powder diffraction and photo-absorption with the cyanide complex were performed individually and simultaneously under the temperature changes. As a result, the coincident measurement system performed successfully the one-to-one corresponding measurement between X-ray diffraction and photo-absorption. In addition, the monitoring of the photo-absorption informed us the property change of the material for the measurement condition and the sample transformation by temperature, laser etc. as well as damage by high-brilliance synchrotron radiation X-ray beam.

  19. In situ spectrophotometric measurement of dissolved inorganic carbon in seawater

    USGS Publications Warehouse

    Liua, Xuewu; Byrne, Robert H.; Adornato, Lori; Yates, Kimberly K.; Kaltenbacher, Eric; Ding, Xiaoling; Yang, Bo

    2013-01-01

    Autonomous in situ sensors are needed to document the effects of today’s rapid ocean uptake of atmospheric carbon dioxide (e.g., ocean acidification). General environmental conditions (e.g., biofouling, turbidity) and carbon-specific conditions (e.g., wide diel variations) present significant challenges to acquiring long-term measurements of dissolved inorganic carbon (DIC) with satisfactory accuracy and resolution. SEAS-DIC is a new in situ instrument designed to provide calibrated, high-frequency, long-term measurements of DIC in marine and fresh waters. Sample water is first acidified to convert all DIC to carbon dioxide (CO2). The sample and a known reagent solution are then equilibrated across a gas-permeable membrane. Spectrophotometric measurement of reagent pH can thereby determine the sample DIC over a wide dynamic range, with inherent calibration provided by the pH indicator’s molecular characteristics. Field trials indicate that SEAS-DIC performs well in biofouling and turbid waters, with a DIC accuracy and precision of ∼2 μmol kg–1 and a measurement rate of approximately once per minute. The acidic reagent protects the sensor cell from biofouling, and the gas-permeable membrane excludes particulates from the optical path. This instrument, the first spectrophotometric system capable of automated in situ DIC measurements, positions DIC to become a key parameter for in situ CO2-system characterizations.

  20. In situ spectrophotometric measurement of dissolved inorganic carbon in seawater.

    PubMed

    Liu, Xuewu; Byrne, Robert H; Adornato, Lori; Yates, Kimberly K; Kaltenbacher, Eric; Ding, Xiaoling; Yang, Bo

    2013-10-01

    Autonomous in situ sensors are needed to document the effects of today's rapid ocean uptake of atmospheric carbon dioxide (e.g., ocean acidification). General environmental conditions (e.g., biofouling, turbidity) and carbon-specific conditions (e.g., wide diel variations) present significant challenges to acquiring long-term measurements of dissolved inorganic carbon (DIC) with satisfactory accuracy and resolution. SEAS-DIC is a new in situ instrument designed to provide calibrated, high-frequency, long-term measurements of DIC in marine and fresh waters. Sample water is first acidified to convert all DIC to carbon dioxide (CO2). The sample and a known reagent solution are then equilibrated across a gas-permeable membrane. Spectrophotometric measurement of reagent pH can thereby determine the sample DIC over a wide dynamic range, with inherent calibration provided by the pH indicator's molecular characteristics. Field trials indicate that SEAS-DIC performs well in biofouling and turbid waters, with a DIC accuracy and precision of ∼2 μmol kg(-1) and a measurement rate of approximately once per minute. The acidic reagent protects the sensor cell from biofouling, and the gas-permeable membrane excludes particulates from the optical path. This instrument, the first spectrophotometric system capable of automated in situ DIC measurements, positions DIC to become a key parameter for in situ CO2-system characterizations.

  1. In situ Measurements of Phytoplankton Fluorescence Using Low Cost Electronics

    PubMed Central

    Leeuw, Thomas; Boss, Emmanuel S.; Wright, Dana L.

    2013-01-01

    Chlorophyll a fluorometry has long been used as a method to study phytoplankton in the ocean. In situ fluorometry is used frequently in oceanography to provide depth-resolved estimates of phytoplankton biomass. However, the high price of commercially manufactured in situ fluorometers has made them unavailable to some individuals and institutions. Presented here is an investigation into building an in situ fluorometer using low cost electronics. The goal was to construct an easily reproducible in situ fluorometer from simple and widely available electronic components. The simplicity and modest cost of the sensor makes it valuable to students and professionals alike. Open source sharing of architecture and software will allow students to reconstruct and customize the sensor on a small budget. Research applications that require numerous in situ fluorometers or expendable fluorometers can also benefit from this study. The sensor costs US$150.00 and can be constructed with little to no previous experience. The sensor uses a blue LED to excite chlorophyll a and measures fluorescence using a silicon photodiode. The sensor is controlled by an Arduino microcontroller that also serves as a data logger. PMID:23783738

  2. IN SITU Device for Real-Time Catalyst Deactivation Measurements

    SciTech Connect

    Fossil Energy Research

    2008-03-31

    SCR catalyst management has become an important operations and maintenance activity for coal-fired utility boilers in the United States. To facilitate this activity, a method to determine Catalyst Activity in situ is being developed. This report describes the methodology and presents the results of a two ozone season demonstration conducted at Alabama Power Company's Gorgas Unit 10 during the 2005 and 2006 ozone seasons. The results showed that the in situ measurements are in good agreement with the laboratory measurements and the technique has some advantages over the traditional laboratory method of determining Catalyst Activity and Reactor Potential. SCR Performance is determined by the overall Reactor Potential (the product of the Catalyst Activity and the available surface area per unit of flue gas). The in situ approach provides a direct measurement of Reactor Potential under actual operating conditions, whereas laboratory measurements of Catalyst Activity need to be coupled with estimates of catalyst pluggage and flue gas flowrate in order to assess Reactor Potential. The project also showed that the in situ activity results can easily be integrated into catalyst management software to aid in making informed catalyst decisions.

  3. A Laboratory Test Setup for in Situ Measurements of the Dielectric Properties of Catalyst Powder Samples under Reaction Conditions by Microwave Cavity Perturbation: Set up and Initial Tests

    PubMed Central

    Dietrich, Markus; Rauch, Dieter; Porch, Adrian; Moos, Ralf

    2014-01-01

    The catalytic behavior of zeolite catalysts for the ammonia-based selective catalytic reduction (SCR) of nitrogen oxides (NOX) depends strongly on the type of zeolite material. An essential precondition for SCR is a previous ammonia gas adsorption that occurs on acidic sites of the zeolite. In order to understand and develop SCR active materials, it is crucial to know the amount of sorbed ammonia under reaction conditions. To support classical temperature-programmed desorption (TPD) experiments, a correlation of the dielectric properties with the catalytic properties and the ammonia sorption under reaction conditions appears promising. In this work, a laboratory test setup, which enables direct measurements of the dielectric properties of catalytic powder samples under a defined gas atmosphere and temperature by microwave cavity perturbation, has been developed. Based on previous investigations and computational simulations, a resonator cavity and a heating system were designed, installed and characterized. The resonator cavity is designed to operate in its TM010 mode at 1.2 GHz. The first measurement of the ammonia loading of an H-ZSM-5 zeolite confirmed the operating performance of the test setup at constant temperatures of up to 300 °C. It showed how both real and imaginary parts of the relative complex permittivity are strongly correlated with the mass of stored ammonia. PMID:25211199

  4. In situ sensors for measurements in the global trosposphere

    NASA Technical Reports Server (NTRS)

    Saeger, M. L.; Eaton, W. C.; Wright, R. S.; White, J. H.; Tommerdahl, J. B.

    1981-01-01

    Current techniques available for the in situ measurement of ambient trace gas species, particulate composition, and particulate size distribution are reviewed. The operational specifications of the various techniques are described. Most of the techniques described are those that have been used in airborne applications or show promise of being adaptable to airborne applications. Some of the instruments described are specialty items that are not commercially-available. In situ measurement techniques for several meteorological parameters important in the study of the distribution and transport of ambient air pollutants are discussed. Some remote measurement techniques for meteorological parameters are also discussed. State-of-the-art measurement capabilities are compared with a list of capabilities and specifications desired by NASA for ambient measurements in the global troposphere.

  5. Investigation of ice cloud microphysical properties of DCSs using aircraft in situ measurements during MC3E over the ARM SGP site

    NASA Astrophysics Data System (ADS)

    Wang, Jingyu; Dong, Xiquan; Xi, Baike

    2015-04-01

    Six deep convective systems (DCSs) with a total of 5589 five-second samples and a range of temperatures from -41°C to 0°C during the Midlatitude Continental Convective Clouds Experiment (MC3E) were selected to investigate the ice cloud microphysical properties of DCSs over the Department of Energy Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site. The ice cloud measurements of the DCS cases were made by the University of North Dakota Citation II research aircraft, and the ice cloud properties were derived through the following processes. First, the instances of supercooled liquid water in the ice-dominated cloud layers of DCSs have been eliminated using multisensor detection, including the Rosemount Icing Detector, King and Cloud Droplet Probes, as well as 2DC and Cloud Imaging Probe images. Then the Nevzorov-measured ice water contents (IWCs) at maximum diameter Dmax < 4000 µm are used as the best estimation to determine a new mass-dimensional relationship. Finally, the newly derived mass-dimensional relationship (a = 0.00365, b = 2.1) has been applied to a full spectrum of particle size distributions (PSDs, 120-30,000 µm) constructed from both 2DC and High-Volume Precipitation Spectrometer measurements to calculate the best-estimated IWCs of DCSs during MC3E. The averages of the total number concentrations (Nt), median mass diameter (Dm), maximum diameter (Dmax), and IWC from six selected cases are 0.035 cm-3, 1666 µm, 8841 µm, and 0.45 g m-3, respectively. The gamma-type-size distributions are then generated matching the observed PSDs (120-30,000 µm), and the fitted gamma parameters are compared with the observed PSDs through multimoment assessments including first moment (Dm), third moment (IWC), and sixth moment (equivalent radar reflectivity, Ze). For application of observed PSDs to the remote sensing community, a series of empirical relationships between fitted parameters and Ze values has been derived, and the bullet rosette

  6. In-situ measurements of the radioactive fallout deposit

    NASA Astrophysics Data System (ADS)

    Korun, M.; Martinčič, R.; Pucelj, B.

    1991-02-01

    An improved method to determine radionuclide concentrations in soil and the radioactive fallout deposit is presented. The approach is based on in-situ gamma-ray spectrometric measurements performed with a portable high resolution gamma spectrometer and on calculations of the depth distribution based on the energy dependence of the attenuation of gamma rays in soil. The results are compared with laboratory analysis of collected soil samples.

  7. Factors influencing in situ gamma-ray measurements

    NASA Astrophysics Data System (ADS)

    Loonstra, E. H.; van Egmond, F. M.

    2009-04-01

    Introduction In situ passive gamma-ray sensors are very well suitable for mapping physical soil properties. In order to make a qualitative sound soil map, high quality input parameters for calibration are required. This paper will focus on the factors that affect the output of in situ passive gamma-ray sensors, the primary source, soil, not taken into account. Factors The gamma-ray spectrum contains information of naturally occurring nuclides 40K, 238U and 232Th and man-made nuclides like 137Cs, as well as the total count rate. Factors that influence the concentration of these nuclides and the count rate can be classified in 3 categories. These are sensor design, environmental conditions and operational circumstances. Sensor design The main elements of an in situ gamma-ray sensor that influence the outcome and quality of the output are the crystal and the spectrum analysis method. Material and size of the crystal determine the energy resolution. Though widely used, NaI crystals are not the most efficient capturer of gamma radiation. Alternatives are BGO and CsI. BGO has a low peak resolution, which prohibits use in cases where man-made nuclides are subject of interest. The material is expensive and prone to temperature instability. CsI is robust compared to NaI and BGO. The density of CsI is higher than NaI, yielding better efficiency, especially for smaller crystal sizes. More volume results in higher energy efficiency. The reduction of the measured spectral information into concentration of radionuclides is mostly done using the Windows analysis method. In Windows, the activities of the nuclides are found by summing the intensities of the spectrum found in a certain interval surrounding a peak. A major flaw of the Windows method is the limited amount of spectral information that is incorporated into the analysis. Another weakness is the inherent use of ‘stripping factors' to account for contributions of radiation from nuclide A into the peak of nuclide B. This

  8. Measuring in situ primary and competitive hybridization events on microspheres

    NASA Astrophysics Data System (ADS)

    Milam, Valeria; Hardin, James

    2012-02-01

    Understanding hybridization events at surfaces is crucial for optimizing nucleic acid detection platforms as well as DNA-mediated colloidal assembly. We used flow cytometry to measure time-dependent primary and competitive hybridization events of perfectly matched and mismatched targets on microsphere surfaces. In addition to more conventional sample preparation involving multiple wash and resuspension steps prior to measurement, we sampled the reaction volume directly for in situ measurements to minimize potential dissociation events between weaker partner strands during wash steps. Similar to prior reports for oligonucletide solutions, the nearly identical rates for primary hybridization events on microsphere surfaces were independent of target sequence and reached an equilibrium value within 30 min. The extent of in situ primary hybridization events for immobilized probes, however, deviated from solution model predictions. In situ competitive hybridization events were at least 100-fold slower than primary hybridization events and did not appear to reach equilibrium. The kinetics of competitive hybridization events on microspheres are consistent with predicted effects stemming from toehold effects or base length differences between primary and secondary targets.

  9. In situ measurement of tritium permeation through stainless steel

    SciTech Connect

    Walter G. Luscher; David J. Senor; Kevin K. Clayton; Glen R. Longhurst

    2013-06-01

    The TMIST-2 irradiation experiment was conducted in the Advanced Test Reactor at Idaho National Laboratory to evaluate tritium permeation through Type 316 stainless steel (316 SS). The interior of a 316 SS seamless tube specimen was exposed to a 4He carrier gas mixed with a specified quantity of tritium (T2) to yield partial pressures of 0.1, 5, and 50 Pa at 292 degrees C and 330 degrees C. In situ tritium permeation measurements were made by passing a He-Ne sweep gas over the outer surface of the specimen to carry the permeated tritium to a bubbler column for liquid scintillation counting. Results from in situ permeation measurements were compared with predictions based on an ex-reactor permeation correlation in the literature. In situ permeation data were also used to derive an in-reactor permeation correlation as a function of temperature and pressure over the ranges considered in this study. In addition, the triton recoil contribution to tritium permeation, which results from the transmutation of 3He to T, was also evaluated by introducing a 4He carrier gas mixed with 3He at a partial pressure of 1013 Pa at 330 degrees C. Less than 3% of the tritium resulting from 3He transmutation contributed to tritium permeation.

  10. Comparison between S. T. radar and in situ balloon measurements

    NASA Technical Reports Server (NTRS)

    Dalaudier, F.; Barat, J.; Bertin, F.; Brun, E.; Crochet, M.; Cuq, F.

    1986-01-01

    A campaign for simultaneous in situ and remote observation of both troposphere and stratosphere took place near Aire-sur-l'Adour (in southeastern France) on May 4, 1984. The aim of this campaign was a better understanding of the physics of radar echoes. The backscattered signal obtained with a stratosphere-troposphere radar both at the vertical and 15 deg. off vertical is compared with the velocity and temperature measurements made in the same region (about 10 km north of the radar site) by balloon-borne ionic anenometers and temperature sensors. In situ measurements clearly indicate that the temperature fluctuations are not always consistent with the standard turbulent theory. Nevertheless, the assumptions generally made (isotropy and turbulent field in k) and the classical formulation so derived for radar reflectivity are able to reproduce the shape of the radar return power profiles in oblique directions. Another significant result is the confirmation of the role played by the atmospheric stratification in the vertical echo power. It is important to develop these simultaneous in situ and remote experiments for a better description of the dynamical and thermal structure of the atmosphere and for a better understanding of the mechanisms governing clear-air radar reflectivity.

  11. Combining Remote Sensing with in situ Measurements for Riverine Characterization

    NASA Astrophysics Data System (ADS)

    Calantoni, J.; Palmsten, M. L.; Simeonov, J.; Dobson, D. W.; Zarske, K.; Puleo, J. A.; Holland, K. T.

    2014-12-01

    At the U.S. Naval Research Laboratory we are employing a wide variety of novel remote sensing techniques combined with traditional in situ sampling to characterize riverine hydrodynamics and morphodynamics. Surface currents were estimated from particle image velocimetry (PIV) using imagery from visible to infrared bands, from both fixed and airborne platforms. Terrestrial LIDAR has been used for subaerial mapping from a fixed platform. Additionally, LIDAR has been combined with hydrographic surveying (multibeam) in mobile scanning mode using a small boat. Hydrographic surveying (side scan) has also been performed using underwater autonomous vehicles. Surface drifters have been deployed in combination with a remotely operated, floating acoustic Doppler current profiler. Other fixed platform, in situ sensors, such as pencil beam and sector scanning sonars, acoustic Doppler velocimeters, and water level sensors have been deployed. We will present an overview of a variety of measurements from different rivers around the world focusing on validation examples of remotely sensed quantities with more traditional in situ measurements. Finally, we will discuss long-term goals to use remotely sensed data within an integrated environmental modeling framework.

  12. In situ measurement of tritium permeation through stainless steel

    NASA Astrophysics Data System (ADS)

    Luscher, Walter G.; Senor, David J.; Clayton, Kevin K.; Longhurst, Glen R.

    2013-06-01

    The TMIST-2 irradiation experiment was conducted in the Advanced Test Reactor at Idaho National Laboratory to evaluate tritium permeation through Type 316 stainless steel (316 SS). The interior of a 316 SS seamless tube specimen was exposed to a 4He carrier gas mixed with a specified quantity of tritium (T2) to yield partial pressures of 0.1, 5, and 50 Pa at 292 °C and 330 °C. In situ tritium permeation measurements were made by passing a He-Ne sweep gas over the outer surface of the specimen to carry the permeated tritium to a bubbler column for liquid scintillation counting. Results from in situ permeation measurements were compared with predictions based on an ex-reactor permeation correlation in the literature. In situ permeation data were also used to derive an in-reactor permeation correlation as a function of temperature and pressure over the ranges considered in this study. In addition, the triton recoil contribution to tritium permeation, which results from the transmutation of 3He to T, was also evaluated by introducing a 4He carrier gas mixed with 3He at a partial pressure of 1013 Pa at 330 °C. Less than 3% of the tritium resulting from 3He transmutation contributed to tritium permeation.

  13. IN-SITU MEASUREMENT OF TRITIUM PERMEATION THROUGH STAINLESS STEEL

    SciTech Connect

    Luscher, Walter G.; Senor, David J.; Clayton, Kevin; Longhurst, Glen R.

    2013-06-01

    The TMIST-2 irradiation experiment was conducted in the Advanced Test Reactor at Idaho National Laboratory to evaluate tritium permeation through Type 316 stainless steel (316 SS). The interior of a 316 SS seamless tube specimen was exposed to a 4He carrier gas mixed with a specified quantity of tritium (T2) to yield partial pressures of 0.1, 5, and 50 Pa at 292° and 330°C. In-situ tritium permeation measurements were made by passing a He-Ne sweep gas over the outer surface of the specimen to carry the permeated tritium to a bubbler column for liquid scintillation counting. An irradiation enhancement factor (IEF) was determined by comparing in-situ permeation data with a correlation for ex-reactor hydrogen permeation through austenitic stainless steel developed from literature data and reported by Le Claire. Nominal values for the IEF ranged between 3 and 5 for 316 SS. In-situ permeation data were also used to derive an in-reactor permeation correlation as a function of temperature and pressure. In addition, the triton recoil contribution to tritium permeation, which results from the transmutation of 3He to T, was also evaluated by introducing a 4He carrier gas mixed with 3He at a partial pressure of 1013 Pa at 330°C. Less than 3% of the tritium resulting from 3He transmutation contributed to tritium permeation.

  14. In Situ Measurement of Tritium Permeation Through Stainless Steel

    SciTech Connect

    Luscher, Walter G.; Senor, David J.; Clayton, Kevin; Longhurst, Glen

    2013-06-01

    The TMIST-2 irradiation experiment was conducted in the Advanced Test Reactor at Idaho National Laboratory to evaluate tritium permeation through Type 316 stainless steel (316 SS). The interior of a 316 SS seamless tube specimen was exposed to a 4He carrier gas mixed with a specified quantity of tritium (T2) to yield partial pressures of 0.1, 5, and 50 Pa at 292° and 330°C. In-situ tritium permeation measurements were made by passing a He-Ne sweep gas over the outer surface of the specimen to carry the permeated tritium to a bubbler column for liquid scintillation counting. An irradiation enhancement factor (IEF) was determined by comparing in-situ permeation data with a correlation for ex-reactor hydrogen permeation through austenitic stainless steel developed from literature data and reported by Le Claire. Nominal values for the IEF ranged between 3 and 5 for 316 SS. In-situ permeation data were also used to derive an in-reactor permeation correlation as a function of temperature and pressure. In addition, the triton recoil contribution to tritium permeation, which results from the transmutation of 3He to T, was also evaluated by introducing a 4He carrier gas mixed with 3He at a partial pressure of 1013 Pa at 330°C. Less than 3% of the tritium resulting from 3He transmutation contributed to tritium permeation.

  15. Dissolved-oxygen quenching of in-situ fluorescence measurements

    NASA Astrophysics Data System (ADS)

    Chudyk, Wayne; Tonaszuck, David; Pohlig, Kenneth

    1993-04-01

    In-situ fluorescence measurements of aromatic organic ground water contaminants do not always agree with gas chromatographic methods. Dissolved oxygen quenching of fluorescence may be an interferant in field measurements. Two standard fluorescent aromatics, quinine sulfate and naphthalene, were evaluated in this study. Over the range of dissolved oxygen concentrations expected to be encountered in the field, no effects of oxygen quenching on fluorescence of these compounds was observed. Quenching of quinine sulfate fluorescence by sodium chloride was observed using this system. Sodium chloride quenching was shown to follow the Stern-Volmer relation.

  16. Development of in-situ micro-debris measurement system

    NASA Astrophysics Data System (ADS)

    Nakamura, Maki; Kitazawa, Yukihito; Matsumoto, Haruhisa; Okudaira, Osamu; Hanada, Toshiya; Sakurai, Akira; Funakoshi, Kunihiro; Yasaka, Tetsuo; Hasegawa, Sunao; Kobayashi, Masanori

    2015-08-01

    The in-situ debris environment awareness system has been developed. The objective of the system is to measure small debris (between 100 μm and several cm) in orbit. The orbital distribution and the size distribution of the debris are not well understood. The size distribution is difficult to measure from the ground, although the size distribution is very important for the risk evaluation of the impact of debris on spacecraft. The in-situ measurement of the size distribution is useful for: (1) verification of meteoroid and debris environment models, (2) verification of meteoroid and debris environment evolution models, (3) real time detection of unexpected events, such as explosions and/or collisions on an orbit. This paper reports the development study of the in-situ debris measurement system and shows demonstration experiments and their results to describe the performance of the micro-debris sensor system. The sensor system for monitoring micro-debris with sizes ranging from 100 μm to a few mm must have a large detection area, while the constraints of space deployment require that these systems be low in mass, low in power, robust and have low telemetry requirements. For this reason, we have been developing a simple trans-film sensor. Thin and conductive stripes (copper) are formed with fine pitch (100 μm) on a thin film of nonconductive material (12.5-μm thick polyimide). A hypervelocity micro-particle impact is detected when one or more stripes are severed by perforation of the film. We designed a debris detector specialized for measuring the micro-debris size and collision rate. We then manufactured and calibrated the detector.

  17. Analysis of in situ measurements of cirrus anvil outflow dynamics

    NASA Astrophysics Data System (ADS)

    Lederman, J. I.; Whiteway, J. A.

    2012-12-01

    The airborne campaign, EMERALD 2 (Egrett Microphysics Experiment with Radiation, Lidar, and Dynamics,) was conducted out of Darwin, Australia in 2002. Objectives included characterization of the dynamics in the cirrus anvil outflow from tropical deep convection. Two aircraft, the Egrett and King Air, were flown in tandem in the upper troposphere (7 km - 15 km) to collect in situ measurements in the anvil outflow from a storm named "Hector" that occurs on a regular basis over the Tiwi Islands north of Darwin during November and December. Turbulence probes mounted on the wings of the Egrett aircraft were used to measure the wind fluctuations across the anvil and along its length with a spatial resolution of 2 meters. The in situ measurements from the Egrett were coincident with lidar measurements of the cloud structure from the King Air aircraft flying directly below. The presentation will show results of the analysis of the measurements with an emphasis on the turbulence, gravity waves, and coherent structures that are particular to the cirrus anvil outflow environment. Emphasis is placed on the dynamics associated with the generation of mammatus formations at the base of the anvil clouds.

  18. Properties of Cerro Prieto rock at simulated in situ conditions

    SciTech Connect

    Schatz, J.F.

    1981-01-01

    Rocks from the Cerro Prieto Geothermal Field were tested under simulated in situ conditions in the laboratory to determine their properties and response to pore pressure reduction as would be caused by reservoir production. The primary purpose of the project was to provide information on compaction and creep as they may contribute to surface subsidence. Results show typical compressibilities for reservoir rocks of about 1 x 10/sup -6/ psi/sup -1/ and creep compaction rates of about 1 x 10/sup -9/ sec/sup -1/ when triggered by 1000 psi pore pressure reduction. This creep rate would cause significant porosity reduction if it continued for several years. Therefore it becomes important to learn how to correctly extrapolate such data to long times.

  19. Enhanced functional connectivity properties of human brains during in-situ nature experience.

    PubMed

    Chen, Zheng; He, Yujia; Yu, Yuguo

    2016-01-01

    In this study, we investigated the impacts of in-situ nature and urban exposure on human brain activities and their dynamics. We randomly assigned 32 healthy right-handed college students (mean age = 20.6 years, SD = 1.6; 16 males) to a 20 min in-situ sitting exposure in either a nature (n = 16) or urban environment (n = 16) and measured their Electroencephalography (EEG) signals. Analyses revealed that a brief in-situ restorative nature experience may induce more efficient and stronger brain connectivity with enhanced small-world properties compared with a stressful urban experience. The enhanced small-world properties were found to be correlated with "coherent" experience measured by Perceived Restorativeness Scale (PRS). Exposure to nature also induces stronger long-term correlated activity across different brain regions with a right lateralization. These findings may advance our understanding of the functional activities during in-situ environmental exposures and imply that a nature or nature-like environment may potentially benefit cognitive processes and mental well-being. PMID:27547533

  20. Enhanced functional connectivity properties of human brains during in-situ nature experience

    PubMed Central

    2016-01-01

    In this study, we investigated the impacts of in-situ nature and urban exposure on human brain activities and their dynamics. We randomly assigned 32 healthy right-handed college students (mean age = 20.6 years, SD = 1.6; 16 males) to a 20 min in-situ sitting exposure in either a nature (n = 16) or urban environment (n = 16) and measured their Electroencephalography (EEG) signals. Analyses revealed that a brief in-situ restorative nature experience may induce more efficient and stronger brain connectivity with enhanced small-world properties compared with a stressful urban experience. The enhanced small-world properties were found to be correlated with “coherent” experience measured by Perceived Restorativeness Scale (PRS). Exposure to nature also induces stronger long-term correlated activity across different brain regions with a right lateralization. These findings may advance our understanding of the functional activities during in-situ environmental exposures and imply that a nature or nature-like environment may potentially benefit cognitive processes and mental well-being. PMID:27547533

  1. Enhanced functional connectivity properties of human brains during in-situ nature experience.

    PubMed

    Chen, Zheng; He, Yujia; Yu, Yuguo

    2016-01-01

    In this study, we investigated the impacts of in-situ nature and urban exposure on human brain activities and their dynamics. We randomly assigned 32 healthy right-handed college students (mean age = 20.6 years, SD = 1.6; 16 males) to a 20 min in-situ sitting exposure in either a nature (n = 16) or urban environment (n = 16) and measured their Electroencephalography (EEG) signals. Analyses revealed that a brief in-situ restorative nature experience may induce more efficient and stronger brain connectivity with enhanced small-world properties compared with a stressful urban experience. The enhanced small-world properties were found to be correlated with "coherent" experience measured by Perceived Restorativeness Scale (PRS). Exposure to nature also induces stronger long-term correlated activity across different brain regions with a right lateralization. These findings may advance our understanding of the functional activities during in-situ environmental exposures and imply that a nature or nature-like environment may potentially benefit cognitive processes and mental well-being.

  2. Two Decades of in situ Halocarbon Trace Gas Measurements

    NASA Astrophysics Data System (ADS)

    Dutton, G.; Nance, J. D.; Elkins, J. W.; Hall, B.; Thompson, T.

    2006-12-01

    Motivated by the signing of the Montreal Protocol in 1987 and interests in greenhouse gases, the NOAA Halocarbons and other Atmospheric Trace Species (HATS) group (now in the ESRL/GMD laboratory) focused on frequently measuring some of the regulated ozone depleting gases such as chlorofluorocarbons (CFC-11 and CFC-12), methyl chloroform (CH3CCl3), and carbon tetrachloride (CCl4). The original HATS in situ program, the Radiatively Important Trace Species (RITS) program, measured these four gases and nitrous oxide (N2O) using gas chromatographic (GC) techniques. The RITS GCs were deployed at the NOAA baseline observatories and a cooperative research station where they remained in operation for the next 13 years. Throughout the 1990s, the HATS in situ and flask programs documented the steady decline in global growth rates of the major chlorinated solvents and chlorofluorocarbons as a result of the Montreal Protocol. Widespread use of the replacement compounds to the now banned CFCs prompted improvements to the HATS in situ program. The RITS instruments were replaced from 1998-2000 by the four-channel Chromatograph for Atmospheric Trace Species (CATS) GCs. In addition to the gases measured by RITS, the CATS GCs added nine compounds including halon-1211, methyl chloride (CH3Cl) and CFC alternatives such as HFC-142b and HCFC-22. Since the RITS instruments have been taken offline, efforts have been focused on finalizing this important data set. A number of calibration scale changes from and improvements with the data reduction algorithms have facilitated comparing and combining the RITS and CATS data sets. In particular, the RITS calibration gas concentration tables were updated to reflect the most recent calibration scale changes. Ratios of calibration gas concentrations were fitted to ratios of RITS system responses to those gases in order to derive a detector response nonlinearity factor for each compound measured. The residuals of these fits were used to

  3. In situ measurements of the mesosphere and stratosphere

    NASA Technical Reports Server (NTRS)

    Crosky, C.

    1976-01-01

    The operation of a subsonic, Gerdien condenser probe for in situ measurements of the mesosphere and stratosphere is presented. The inclusion of a flashing Lyman alpha ultraviolet source provides an artifically produced ionization of particular constituents. Detailed theory of operation is presented and the data results from two flights are shown. A great deal of fine structure in mobility is observed due to the presence of various hydrated positive ions. The effect of the Lyman alpha source in the 35 km region was to dissociate a light hydrate ion rather than produce additional ionization. At the 70 km region, photodissociation of the heaviest ions (probably ice crystals) was also observed.

  4. In situ measurements of magnetic nanoparticles after placenta perfusion

    NASA Astrophysics Data System (ADS)

    Müller, Robert; Gläser, Marcus; Göhner, Claudia; Seyfarth, Lydia; Schleussner, Ekkehard; Hofmann, Andreas; Fritzsche, Wolfgang

    2015-04-01

    Nanoparticles (NP) present promising tools for medical applications. However, the investigation of their spatial and temporal distribution is hampered by missing in-situ particle detection and quantification technologies. The placenta perfusion experiment represents an interesting model for the study of the particle distribution at a biological barrier. It allows the ex-vivo investigation of the permeability of the placenta for materials of interest. We introduce an approach based on a magnetic system for an in situ measurement of the concentration of magnetic NPs in such an experiment. A previously off-line utilized magnetic readout device (sensitivity of ≈10-8 Am2) was used for long term measurements of magnetic NP of 100-150 nm size range in a closed circuit of a placenta perfusion. It represents a semiquantitative approach. The behavior of particles in the placenta and in the measurement system was studied, as well as the influence of particle surface modifications. The results suggest a transfer of a low amount of particles from the maternal to the fetal blood circuit.

  5. Statistical modeling of in situ hiss amplitudes using ground measurements

    NASA Astrophysics Data System (ADS)

    Golden, D. I.; Spasojevic, M.; Li, W.; Nishimura, Y.

    2012-05-01

    Plasmaspheric hiss is a naturally occurring extremely low frequency electromagnetic emission that is often observed within the Earth's plasmasphere. Plasmaspheric hiss plays a major role in the scattering and loss of electrons from the Earth's radiation belts, thereby contributing to the maintenance of the slot region between the inner and outer electron belt. Traditionally, in situ satellite observations have been the measurement modality of choice for studies of plasmaspheric hiss due to their ability to directly measure the hiss source region. However, satellite studies are relatively short-lived and very few satellite receivers remain operational for an entire 11-year solar cycle. Ground stations, in contrast, may collect multiple solar cycles' worth of data during their lifetime, yet they cannot directly measure the hiss source region. This study aims to determine the extent to which measurements of hiss at midlatitude ground stations may be used to predict the mean amplitude of in situ measurements of plasmaspheric hiss. We use coincident measurements between Palmer Station, Antarctica (L = 2.4, 50°S invariant latitude) and the THEMIS spacecraft from June 2008 through May 2010, during solar minimum. Using an autoregressive multiple regression model, we show that in the local time sector from 00 < MLT < 12, when the ionosphere above Palmer Station is in darkness and hiss is observed at Palmer, the amplitude of plasmaspheric hiss observed by the THEMIS spacecraft is 1.4 times higher than when hiss is not observed at Palmer. In the same local time sector when the ground station is in daylight and hiss is observed, the THEMIS observed amplitudes are not significantly different from those when hiss is not observed on the ground. A stronger relationship is found in the local time sector from 12 < MLT < 24 where, when Palmer is in daylight and hiss is observed, THEMIS plasmaspheric hiss amplitudes are 2 times higher compared to when hiss is not observed at Palmer

  6. In situ Micrometeorological Measurements during RxCADRE

    NASA Astrophysics Data System (ADS)

    Clements, C. B.; Hiers, J. K.; Strenfel, S. J.

    2009-12-01

    The Prescribed Fire Combustion and Atmospheric Dynamics Research Experiment (RxCADRE) was a collaborative research project designed to fully instrument prescribed fires in the Southeastern United States. Data were collected on pre-burn fuel loads, post burn consumption, ambient weather, in situ atmospheric dynamics, plume dynamics, radiant heat release (both from in-situ and remote sensors), in-situ fire behavior, and select fire effects. The sampling was conducted at Eglin Air Force Base, Florida, and the Joseph W. Jones Ecological Research Center in Newton, Georgia, from February 29 to March 6, 2008. Data were collected on 5 prescribed burns, totaling 4458 acres. The largest aerial ignition totaled 2,290 acres and the smallest ground ignition totaled 104 acres. Quantifying fire-atmospheric interactions is critical for understanding wildland fire dynamics and enhancing modeling of smoke plumes. During Rx-CADRE, atmospheric soundings using radiosondes were made at each burn prior to ignition. In situ micrometeorological measurements were made within each burn unit using five portable, 10-m towers equipped with sonic and prop anemometers, fine-wire thermocouples, and a carbon dioxide probes. The towers were arranged within the burn units to capture the wind and temperature fields as the fire front and plume passed the towers. Due to the interaction of fire lines following ignition, several of the fire fronts that passed the towers were backing fires and thus less intense. Preliminary results indicate that the average vertical velocities associated with the fire front passage were on the order of 3-5 m s-1 and average plume temperatures were on the order of 30-50 °C above ambient. During two of the experimental burns, radiosondes were released into the fire plumes to determine the vertical structure of the plume temperature, humidity, and winds. A radiosonde released into the plume during the burn conducted on 3 March 2008 indicated a definite plume boundary in the

  7. In-situ Measurements of Interplanetary and Interstellar Dust

    NASA Astrophysics Data System (ADS)

    Grün, E.

    2008-09-01

    Dust is finely dispersed solid material in interplanetary space. It derives from a number of sources: larger meteoroids, comets, asteroids, the planets, and satellites, and there is interstellar dust sweeping through the solar system. These dust particles range in size from assemblages of a few molecules to tenth millimetre-sized grains. Dust particles absorb and scatter solar radiation and emit thermal radiation giving rise to Zodiacal light at visible and thermal emission at infrared wavelengths. Astronomical observations of both emissions provide information on the average properties of very large number of particles and their spatial distribution. Information on the physical and chemical properties and the orbital motion is obtained by direct methods. Direct methods include: (1) collection of dust particles (Fig. 1) on collectors on spacecraft returned to Earth and on airplanes in the stratosphere, (2) investigations of dust impacts craters on lunar samples and manmade impact plates returned from space, and (3) insitu measurements of individual particles by instruments on board satellites and space probes. Dust particles collected in the upper atmosphere provide the morphology and chemical and mineralogical composition of extraterrestrial particles of 5 to 50 microns in diameter but no information on the source of these particles is obtained. The NASA Stardust mission was the first space mission that returned dust from a comet. The study of impact craters on man-made and lunar surface samples exposed to space is used to characterize the flux of interplanetary micrometeoroids and their size distribution. Microcraters have been found ranging from 0.02 μm to millimetres in diameter. In-situ detectors on board of satellites and spaceprobes for the measurement of interplanetary dust have been used in the ecliptic plane from inside Mercury's orbit to the Kuiper belt and in space above and below the solar poles. Penetration detectors have a detection threshold of

  8. Use of automated in-situ measurements for sensor harmonization

    NASA Astrophysics Data System (ADS)

    Thome, K. J.; Wenny, B. N.; Czapla-Myers, J.

    2015-12-01

    Vicarious calibration approaches using in-situ measurements saw first use in the early 1980s and have since improved to keep pace with the evolution of the sensors that are being calibrated. The advantage to in-situ measurements is that they lead to a well-demonstrated and traceable accuracy. The drawbacks are the costs and labor-intensive nature of those approaches. The development of multi-platform constellations and the need to ensure radiometric consistency across them has led to the implementation of automated ground sites and the accuracy of the results from these automated sites make them suitable for harmonizing the radiometric output from multiple sensors. The results shown here applied to instruments from NASA's Terra platform as well as Landsats 7 and 8 demonstrate the utility of automated sites as well as the feasibility of making the data from such sites more widely available to the instrument teams. The accuracy of the calibration for a single sensor typically meets the calibration requirements for most earth imagers and harmonization to better than 1% is feasible.

  9. In situ measurement of CuPt alloy ordering using strain anisotropy

    SciTech Connect

    France, Ryan M.; McMahon, William E.; Kang, Joongoo; Steiner, Myles A.; Geisz, John F.

    2014-02-07

    The optical and electrical properties of many III-V alloys change with the degree of CuPt atomic ordering, which is very sensitive to growth conditions. The bulk ordered alloy is elongated along the normal to the ordered planes, and is asymmetrically strained when coherent to a cubic substrate. Here, we demonstrate in situ measurement of the anisotropic strain due to ordering using two-dimensional wafer curvature. The measurement is sensitive to bulk anisotropies, and so is complementary to other in situ measurements that are sensitive to surface anisotropies. Using ab initio calculations, we determine a maximum strain anisotropy of 0.27% between [110] and [1{sup ¯}10] when perfectly ordered single-variant GaInP{sub 2} is coherent to a (001) cubic substrate. We relate the in situ measurement of strain anisotropy on various GaInP{sub 2} samples to ex situ measurements of the order parameter to validate the measurement and confirm the capability to predict material properties. The measurement monitors change in ordering during growth, useful for quickly determining the growth condition dependence of ordering or monitoring order-disorder transitions. More generally, this measurement technique could, in principle, be used to monitor phase changes in any epitaxial system for which the strain anisotropy of the two phases differs.

  10. In-situ magnetic gauge measurements in Kel-F

    SciTech Connect

    Sheffield, S.A.; Alcon, R.R.

    1991-01-01

    In-situ gauge measurements have been made in Kel-F using multiple, embedded Lagrangian particle velocity and impulse gauges to measure shock attributes. Shock stresses attained were between 0.9 and 11 GPa. At the lower stresses, we were looking for the effects of a subtle phase transformation to be manifested in the form of a multiple wave structure. Clear evidence of this transformation was not observed but the shape of the transmitted waves indicated the viscoplastic nature of this material. This effect was nearly gone at 2.6 GPa. At the highest stress condition (11 GPa), the waveforms suggest that the single-crystal sapphire impactor was starting to yield, indicating that sapphire is not elastic all the way to 12 GPa, as had been previously thought. Rarefaction speed measurements at shock conditions were obtained from each experiment but it was not possible to obtain accurate estimates of the Gruneisen parameter. 8 refs., 3 figs., 2 tabs.

  11. Charge changing phosphorylated polymers: Proof of in situ mucoadhesive properties.

    PubMed

    Bonengel, Sonja; Jelkmann, Max; Oh, Sejin; Mahmood, Arshad; Ijaz, Muhammad; Bernkop-Schnürch, Andreas

    2016-08-01

    The objective of this study was to design a novel polyethylene glycol (PEG) derivative exhibiting mucus permeating and mucoadhesive properties. Therefore, the enzymatically degradable phosphate ester, phosphotyrosine (Ptyr) was covalently attached to PEG-diamine. The synthesized PEG-Ptyr was studied in terms of enzymatic degradability on Caco 2 cells and by isolated intestinal alkaline phosphatase (IAP). Furthermore, the influence of enzymatic degradation on charge distribution of the polymer as well as on mucus diffusion and mucoadhesion was investigated. Within this study, the phosphate ester in PEG-Ptyr could be cleaved on the cell monolayer and by the isolated IAP, whereby the degradation rate was 10-fold higher utilizing the isolated enzyme. Implementation of negative charges on PEG due to modification with Ptyr led to an increased electrophoretic mobility, which was reduced after enzymatic degradation of the phosphate ester, most likely due to the alterations in charge distribution on the polymeric backbone. Interactions with mucus components were determined within mucus diffusion studies and rheological investigations. Herein, PEG-Ptyr showed a 3-fold lower mucus diffusion, after incubation with IAP. Within rheological investigations, dynamic viscosities increased by the factor of 3, after the phosphate ester in PEG-Ptyr was degraded by IAP. Results obtained within these experiments provided evidence for the in situ mucoadhesive properties of charge changing phosphorylated polymers. The combination of mucus permeating and mucoadhesive features of phosphorylated PEGs could be a highly interesting tool for future applications, such as for coating nanoparticles. PMID:27320696

  12. In-situ impurity measurements in PDX Edge plasma

    SciTech Connect

    Staib, P.; Dylla, H.F.; Rossnagel, S.M.

    1980-07-01

    The surface analysis station of PDX combines several surface analysis techniques (AES, XPS, SIMS) for in-situ measurement of impurity fluxes in the edge-plasma. The major impurities deposited on a sample surface during nondiverted PDX discharges are oxygen, titanium (limiter material) and chlorine. The impurity fluxes measured at different radial positions decreased by a factor of ten from the plasma edge to the wall. The sample surface collecting the impurity ions is located behind a circular aperture. The observed broadening of the deposition profile of Ti relative to the aperture diameter enables an estimate to be made of the ratio of charge state/energy of Ti ions in the edge plasma. Time-resolved analyses of the deposited impurities are presented which indicate that the time behavior for various impurities may be quite different for different impurity species. This aspect is discussed in relation to probable impurity release mechanisms.

  13. Contact sponge water absorption test implemented for in situ measures

    NASA Astrophysics Data System (ADS)

    Gaggero, Laura; Scrivano, Simona

    2016-04-01

    The contact sponge method is a non-destructive in-situ methodology used to estimate a water uptake coefficient. The procedure, unlike other in-situ measurement was proven to be directly comparable to the water uptake laboratory measurements, and was registered as UNI 11432:2011. The UNI Normal procedure requires to use a sponge with known density, soaked in water, weighed, placed on the material for 1 minute (UNI 11432, 2011; Pardini & Tiano, 2004), then weighed again. Difficulties arise in operating on test samples or on materials with porosity varied for decay. While carrying on the test, fluctuations in the bearing of the environmental parameters were negligible, but not the pressure applied to the surface, that induced the release of different water amounts towards the material. For this reason we designed a metal piece of the same diameter of the plate carrying the sponge, to be screwed at the tip of a pocket penetrometer. With this instrument the sponge was kept in contact with the surface for 1 minute applying two different loads, at first pushed with 0.3 kg/cm2 in order to press the sponge, but not its holder, against the surface. Then, a load of 1.1 kg/ cm2 was applied, still avoiding deviating the load to the sponge holder. We applied both the current and our implemented method to determine the water absorption by contact sponge on 5 fresh rock types (4 limestones: Fine - and Coarse grained Pietra di Vicenza, Rosso Verona, Breccia Aurora, and the silicoclastic Macigno sandstone). The results show that 1) the current methodology imply manual skill and experience to produce a coherent set of data; the variable involved are in fact not only the imposed pressure but also the compression mechanics. 2) The control on the applied pressure allowed reproducible measurements. Moreover, 3) the use of a thicker sponge enabled to apply the method even on rougher surfaces, as the device holding the sponge is not in contact with the tested object. Finally, 4) the

  14. In situ multiproperty measurements of individual nanomaterials in SEM and correlation with their atomic structures.

    PubMed

    Ning, Z Y; Fu, M Q; Shi, T W; Guo, Y; Wei, X L; Gao, S; Chen, Q

    2014-07-11

    The relationship between property and structure is one of the most important fundamental questions in the field of nanomaterials and nanodevices. Understanding the multiproperties of a given nano-object also aids in the development of novel nanomaterials and nanodevices. In this paper, we develop for the first time a comprehensive platform for in situ multiproperty measurements of individual nanomaterials using a scanning electron microscope (SEM). Mechanical, electrical, electromechanical, optical, and photoelectronic properties of individual nanomaterials, with lengths that range from less than 200 nm to 20 μm, can be measured in situ with an SEM on the platform under precisely controlled single-axial strain and environment. An individual single-walled carbon nanotube (SWCNT) was measured on the platform. Three-terminal electronic measurements in a field effect transistor structure showed that the SWCNT was semiconducting and agreed with the structure characterization by transmission electron microscopy after the in situ measurements. Importantly, we observed a bandgap increase of this SWCNT with increasing axial strain, and for the first time, the experimental results quantitatively agree with theoretical predictions calculated using the chirality of the SWCNT. The vibration performance of the SWCNT, a double-walled CNT, and a triple-walled CNT were also studied as a function of axial strain, and were proved to be in good agreement with classical beam theory, although the CNTs only have one, two, or three atomic layers, respectively. Our platform has wide applications in correlating multiproperties of the same individual nanostructures with their atomic structures.

  15. Evaporation Measured In Situ by Sensible Heat Balance

    NASA Astrophysics Data System (ADS)

    Heitman, Josh; Xiao, Xinhua; Sauer, Thomas; Ren, Tusheng; Horton, Robert

    2016-04-01

    Measurement of evaporation independent from evapotranspiration remains a major challenge for quantifying water fluxes in the soil-plant-atmosphere system. Methodology based on soil sensible heat balance (SHB) has been developed to measure in situ, sub-surface soil water evaporation with heat-pulse sensors. Soil sensible heat flux and change in heat storage are measured at multiple depths near the soil surface, and a simple energy balance calculation is applied to determine latent heat flux (i.e., evaporation) as a residual. For bare surface conditions, comparison of SHB to micrometerological (Bowen ratio) and micro-lysimeter approaches indicates strong correlation (r2 = 0.96) with near 1:1 relationship and root mean square error of 0.2 mm/d. Recent efforts to apply SHB methodology in row-crop (maize) and vineyard systems demonstrate the potential for quantifying evaporation separate from evapotranspiration. For the maize system, SHB evaporation estimates differed from micro-lysimeters by < 0.2 mm/d. The SHB approach is one of very few measurement approaches that may be applied to partition evaporation from evapotranspiration.

  16. PETher - Physical Properties of Thermal Water under In-situ-Conditions

    NASA Astrophysics Data System (ADS)

    Herfurth, Sarah; Schröder, Elisabeth

    2016-04-01

    The objective of PETher, a research project funded by the German Federal Ministry for Economic Affairs and Energy (BMWi), is to experimentally determine thermo-physical properties (specific isobaric heat capacity, kinematic viscosity, density and thermal conductivity) of geothermal water in-situ-conditions (pressure, temperature, chemical composition including gas content of the brine) present in geothermal applications. Knowing these thermo-physical properties reduces the uncertainties with respect to estimating the thermal output and therefore the economic viability of the power plant. Up to now, only a limited number of measurements of selected physical properties have been made, usually under laboratory conditions and for individual geothermal plants. In-situ measured parameters, especially in the temperature range of 120°C and higher, at pressures of 20 bar and higher, as well as with a salinity of up to 250 g/l, are sparse to non-existing. Therefore, pure water properties are often used as reference data and for designing the power plant and its components. Currently available numerical models describing the thermo-physical properties are typically not valid for the conditions in geothermal applications and do not consider the substantial influence of the chemical composition of the thermal water. Also, actual geothermal waters have not been subject of detailed measurements systematically performed under operational conditions on a large-scale basis. Owing to the lack of reliable data, a validation of numerical models for investigating geothermal systems is not possible. In order to determine the dependency of the thermo-physical properties of geothermal water on temperature, pressure and salinity in-situ measurements are conducted. The measurements are taking place directly at several geothermal applications located in Germany's hydrogeothermal key regions. In order to do this, a mobile testing unit was developed and refined with instruments specifically

  17. A Nanoplasmonic Strategy for Precision in-situ Measurements of Tip-enhanced Raman and Fluorescence Spectroscopy

    PubMed Central

    Meng, Lingyan; Sun, Mengtao; Chen, Jianing; Yang, Zhilin

    2016-01-01

    We theoretically investigate an optimized tip-film system that supports in-situ measurement of tip-enhanced Raman spectroscopy (TERS) and tip-enhanced fluorescence (TEF) of dye molecules. A scanning tunneling microscope (STM) is proposed to precisely control the tip-film distance, and thus in-situ measurement of TERS and TEF can be realized utilizing the specific surface plasmon resonance (SPR) properties of the tip-film system. Our calculations show that the optimized tip-film distance of 2 nm suggests a possibility of efficient acquisition of TERS and TEF in-situ. The calculated spatial resolution of TERS and spectral resolution of TEF can be down to 6.5 nm and 10 nm, respectively. Our theoretical results may find promising application in developing multiple functional nano-spectroscopy through which Raman and fluorescence can be measured in-situ at the nanoscale level. PMID:26780882

  18. In Situ Measurements of Meteoric Ions. Chapter 8

    NASA Technical Reports Server (NTRS)

    Grebowsky, Joseph M.; Aikin, Arthur C.; Vondrak, Richard R. (Technical Monitor)

    2001-01-01

    Metal ions found in the atmosphere above 60 km are the result of incoming meteoroid atmospheric ablation. Layers of metal ions are detected by sounding rocket in situ mass spectrometric sampling in the 80 to 130 km region, which coincides with the altitude region where meteors are observed. Enhancements of metal ion concentrations occur during meteor showers. Even outside of shower periods, the metal ion altitude profiles vary from measurement to measurement. Double layers are frequent at middle latitudes. More than 40 different meteoric atomic and molecular ions, including isotopes, have been detected. Atmospheric metal ions on average have an abundance that matches chrondritic material, the same composition as the early solar system. However there are frequently local departures from this composition due to differential ablation, species dependent chemistry and mass dependent ion transport. Metal ions react with atmospheric O2, O, O3, H2O and H2O2 to form oxygenated and hydrogenated ionic compounds. Metal atomic ions at high altitudes have long lifetimes. As a result, these ions, in the presence of Earth's magnetic field, are transported over long distances by upper atmospheric winds and ionospheric electric fields. Satellite measurements have detected metal ions as high as, approximately 1000 km and have revealed circulation of the ions on a global scale.

  19. In Situ Magnetic Field Measurement using the Hanle Effect

    NASA Astrophysics Data System (ADS)

    Jackson, Jarom; Durfee, Dallin

    2016-05-01

    We have developed a simple method of in situ magnetic field mapping near zero points in magnetic fields. It is ideal for measuring trapping parameters such the field gradient and curvature, and should be applicable in most experiments with a magneto-optical trap (MOT) or similar setup. This method works by probing atomic transitions in a vacuum, and is based on the Hanle effect, which alters the polarization of spontaneous emission in the presence of a magnetic field. Unlike most techniques based on the Hanle effect, however, we look only at intensity. Instead of measuring polarization we use the change in directional radiation patterns caused by a magnetic field. Using one of the cooling beams for our MOT, along with a linear polarizer, a narrow slit, and an inexpensive webcam, we measure the three dimensional position of a magnetic field zero point within our vacuum to within +/-1 mm and the gradient through the zero point to an accuracy of 4%. This work was supported by NSF Grant Number PHY-1205736.

  20. Neutral beam species measurements using in situ Rutherford backscatter spectrometry

    SciTech Connect

    Kugel, H.W.; Kaita, R.; Gammel, G.; Williams, M.D.

    1984-12-01

    This work describes a new in situ method for measuring the neutral particle fractions in high power deuterium neutral beams, used to heat magnetically confined fusion plasmas. Deuterium beams, of variable energies, pulse lengths, and powers up to 47 keV, 100 msec, 1.6 MW, were Rutherford backscattered at 135/sup 0/ from TiC inner neutral beam armor of the PDX, and detected using an electrostatic analyzer with microchannel plates. Complete energy scans were made every 20 msec and data were obtained simultaneously from five different positions across the beam profile. The neutral particle fractions were measured to be D/sup 0/(E):D/sup 0/(E/2):D/sup 0/(E/3)=53:32:15. The corresponding neutral power fractions were P/sup 0/(E):P/sup 0/(E/2):P/sup 0/(E/3)=72:21:7, and the associated ionic fractions at the output of the ion source were D/sub 1//sup +/(E):D/sub 2//sup +/(E):D/sub 3//sup +/(E)=74:20:6. The measured neutral particle fractions were relatively constant over more than 70% of the beam power distribution. A decrease in the yield of the full energy component in the outer regions of the beam was observed. Other possible experimental configurations and geometries are discussed.

  1. Neutral beam species measurements using in situ Rutherford backscatter spectrometry

    SciTech Connect

    Kugel, H.W.; Kaita, R.; Gammel, G.; Williams, M.D.

    1985-05-01

    This work describes a new in situ method for measuring the neutral particle fractions in high-power deuterium neutral beams, used to heat magnetically confined fusion plasmas. Deuterium beams, of variable energies, pulse lengths, and powers up to 47 keV, 100 ms, 1.6 MW, were Rutherford backscattered at 135/sup 0/ from the TiC inner neutral beam armor of the PDX, and detected using an electrostatic analyzer with a microchannel plate. Complete energy scans were made every 20 ms and data were obtained simultaneously from five different positions across the beam profile. The neutral particle fractions were measured to be D/sup 0/(E):D/sup 0/(E/2):D/sup 0/(E/3) = 53:32:15. The corresponding neutral power fractions were P/sup 0/(E):P/sup 0/(E/2):P/sup 0/(E/3) = 72:21:7, and the associated ionic fractions at the output of the ion source were D/sup +//sub 1/ (E):D/sup +//sub 2/ (E):D/sup +//sub 3/ (E) = 74:20:6. The measured neutral particle fractions were relatively constant over more than 70% of the beam power distribution. A decrease in the yield of the full-energy component in the outer regions of the beam was observed.

  2. Neutral beam species measurements using in situ Rutherford backscatter spectrometry

    NASA Astrophysics Data System (ADS)

    Kugel, H. W.; Kaita, R.; Gammel, G.; Williams, M. D.

    1985-05-01

    This work describes a new in situ method for measuring the neutral particle fractions in high-power deuterium neutral beams, used to heat magnetically confined fusion plasmas. Deuterium beams, of variable energies, pulse lengths, and powers up to 47 keV, 100 ms, 1.6 MW, were Rutherford backscattered at 135° from the TiC inner neutral beam armor of the PDX, and detected using an electrostatic analyzer with a microchannel plate. Complete energy scans were made every 20 ms and data were obtained simultaneously from five different positions across the beam profile. The neutral particle fractions were measured to be D0(E):D0(E/2):D0(E/3)=53:32:15. The corresponding neutral power fractions were P0(E):P0(E/2):P0(E/3)=72:21:7, and the associated ionic fractions at the output of the ion source were D+1 (E):D+2 (E):D+3 (E)=74:20:6. The measured neutral particle fractions were relatively constant over more than 70% of the beam power distribution. A decrease in the yield of the full-energy component in the outer regions of the beam was observed.

  3. In situ measurement of inelastic light scattering in natural waters

    NASA Astrophysics Data System (ADS)

    Hu, Chuanmin

    Variation in the shape of solar absorption (Fraunhofer) lines are used to study the inelastic scattering in natural waters. In addition, oxygen absorption lines near 689nm are used to study the solar stimulated chlorophyll fluorescence. The prototype Oceanic Fraunhofer Line Discriminator (OFLD) has been further developed and improved by using a well protected fiber optic - wire conductor cable and underwater electronic housing. A Monte-Carlo code and a simple code have been modified to simulate the Raman scattering, DOM fluorescence and chlorophyll fluorescence. A series of in situ measurements have been conducted in clear ocean waters in the Florida Straits, in the turbid waters of Florida Bay, and in the vicinity of a coral reef in the Dry Tortugas. By comparing the reduced data with the model simulation results, the Raman scattering coefficient, b r with an excitation wavelength at 488nm, has been verified to be 2.6 × 10-4m-1 (Marshall and Smith, 1990), as opposed to 14.4 × 10- 4m-1 (Slusher and Derr, 1975). The wavelength dependence of b r cannot be accurately determined from the data set as the reported values (λ m-4 to λ m- 5) have an insignificant effect in the natural underwater light field. Generally, in clear water, the percentage of inelastic scattered light in the total light field at /lambda < 510nm is negligible for the whole water column, and this percentage increases with depth at /lambda > 510nm. At low concentrations (a y(/lambda = 380nm) less than 0.1m-1), DOM fluorescence plays a small role in the inelastic light field. However, chlorophyll fluorescence is much stronger than Raman scattering at 685nm. In shallow waters where a sea bottom affects the ambient light field, inelastic light is negligible for the whole visible band. Since Raman scattering is now well characterized, the new OFLD can be used to measure the solar stimulated in situ fluorescence. As a result, the fluorescence signals of various bottom surfaces, from coral to

  4. Hybrid-type temperature sensor for in situ measurement

    SciTech Connect

    Iuchi, Tohru; Hiraka, Kensuke

    2006-11-15

    A hybrid-type surface temperature sensor combines the contact and noncontact methods, which allows us to overcome the shortcomings of both methods. The hybrid-type surface thermometer is composed mainly of two components: a metal film sheet that makes contact with an object and a radiometer that is used to detect the radiance of the rear surface of the metal film, which is actually a modified radiation thermometer. Temperature measurement using the hybrid-type thermometer with a several tens micrometer thick Hastelloy sheet, a highly heat and corrosion resistant alloy, is possible with a systematic error of -0.5 K and random errors of {+-}0.5 K, in the temperature range from 900 to 1000 K. This thermometer provides a useful means for calibration of in situ temperature measurement in various processes, especially in the silicon semiconductor industry. This article introduces the basic idea of the hybrid-type surface sensor, presents experimental results and discussions, and finally describes some applications.

  5. Oceanographic lidar profiles compared with estimates from in situ optical measurements.

    PubMed

    Lee, Jennifer H; Churnside, James H; Marchbanks, Richard D; Donaghay, Percy L; Sullivan, James M

    2013-02-01

    Oceanographic lidar profiles measured in an aerial survey were compared with in situ measurements of water optical properties made from a surface vessel. Experimental data were collected over a two-week period in May 2010 in East Sound, Washington. Measured absorption and backscatter coefficients were used with the volume-scattering function in a quasi-single-scattering model to simulate an idealized lidar return, and this was convolved with the measured instrument response to accurately reproduce the measured temporal behavior. Linear depth-dependent depolarization from the water column and localized depolarization from scattering layers are varied to fine tune the simulated lidar return. Sixty in situ measurements of optical properties were correlated with nearly collocated and coincident lidar profiles; our model yielded good matches (±3 dB to a depth of 12 m) between simulated and measured lidar profiles for both uniform and stratified waters. Measured attenuation was slightly higher (5%) than diffuse attenuation for the copolarized channel and slightly lower (8%) for the cross-polarized channel.

  6. KISAP: New in situ seafloor velocity measurement tool

    NASA Astrophysics Data System (ADS)

    Kim, Gil Young; Park, Ki Ju; Kyo Seo, Young; Lee, Gwang Soo; Kim, Seong Pil

    2015-04-01

    The KISAP (KIGAM Seafloor Acoustic Prober) is an instrument developed to obtain in situ compressional wave velocity and attenuation profiles for upper several meters of sedimentary layer at the sediment-seawater interface. This instrument consists of independent recording channels (NI cDAQ-9132, National Instruments) with a linear array of receivers (5 Hz-20 kHz, GeoSpectrum Technologies Inc) with depth below acoustic source (acoustic pinger, 1-50 kHz frequency, GeoSpectrum Technologies Inc). It provides in situ recording of full waveforms to determine interval velocity and attenuation. The system can be attached to a corer (gravity and/or piston corer) or to a specially designed prober. The experiments for in situ test were carried out in east coast of Korea and Songjeong beach, Pusan, Korea. We collected good waveform data to be calculated in situ velocity from KISAP test. Therefore KISAP can be used to collect in situ acoustic data. In addition, it can be effectively used to calibrate previous laboratory data to in situ data.

  7. Measuring auroral precipitation parameters without in situ microchannel plate instrumentation

    NASA Astrophysics Data System (ADS)

    Lynch, K. A.; Hampton, D. L.; Zettergren, M. D.; Conde, M.; Lessard, M.; Michell, R.; Samara, M.

    2013-12-01

    Recent advances in groundbased detector technology have resulted in accurate, high-sensitivity, emission-line filtered images of aurora with sub- to a few- km resolution over a few 100 km region collected at a few second to a few Hz cadence. By combining these images with information from other groundbased instrumentation (ISR, remote photometers, and FPIs) and using well-documented empirical relationships between intensity and precipitating electron characteristics, these images hold the potential for providing an accurate, mesoscale, 2-D time history of the key parameters (characteristic energy and energy flux) of the precipitating electrons that caused the optical aurora within the imager's field of view. In situ measurements can be more accurate, but they are limited to highly localized 1-D line trajectories and are of limited use for meso-scale modeling. However, a limitation of the groundbased technique is that subvisual (low energy) precipitation is not captured. Onboard measurements of total number flux provide low resource measurements capturing specific boundary crossings and gradients as well as net precipitation including the portion not observed optically. The combination of minimal onboard instrumentation supplementing rigorous groundbased inversions can provide an optimal set of inputs for ionospheric modelling tools. Thus we are investigating the capabilities and limitations of using inversions of groundbased observations in the place of in situ precipitation monitors. While several inversion techniques are possible we will discuss two methods used in the analysis of recent rocket experiments. The first, used for the Cascades2 rocket, compares measured altitude profiles of auroral emissions to those from a 1-D electron transport code to confirm optically that two arcs transited by the rocket were produced by significantly different electron spectra. The second method, for the MICA rocket, uses the 2-D temperature maps from the Scanning Doppler

  8. In situ measurements of trace gases and aerosol optical properties at a rural site in northern China during East Asian Study of Tropospheric Aerosols: An International Regional Experiment 2005

    NASA Astrophysics Data System (ADS)

    Li, Can; Marufu, Lackson T.; Dickerson, Russell R.; Li, Zhanqing; Wen, Tianxue; Wang, Yuesi; Wang, Pucai; Chen, Hongbin; Stehr, Jeffrey W.

    2007-11-01

    In situ measurements of trace gases and aerosol optical properties were made in March 2005 at Xianghe (39.798°N, 116.958°E, 35 m), a rural site about 70 km southeast, and generally downwind of the Beijing metropolitan area. High pollutant levels were observed during the experiment, with CO (1.09 ± 1.02 ppmv, average ± standard deviation), SO2 (17.8 ± 15.7 ppbv), NOy (26.0 ± 24.0 ppbv), aerosol scattering coefficients (bsp, (468 ± 472) × 10-6 m-1), and aerosol absorption coefficients (bap, (65 ± 75) × 10-6 m-1) all much higher than observed at some rural sites in the United States. O3 (29.1 ± 16.5 ppbv) was relatively low during this study, suggesting inactive photochemical processes. Strong synoptic fluctuations in pollutant levels were detected every 4-5 days during the experiment, as cold fronts passing over the region drastically reduced the ground-level pollution. Very little precipitation was measured during the whole observational period, implying pollutant uplift and transport by rain-free cold fronts and dry convection. The single scattering albedo (SSA) observed (0.81 in the morning and 0.85 in the afternoon) indicates strongly absorbing aerosols near surface. The observed CO/SO2 ratio (35.8) is higher than inventory values, but closer to the updated CO inventory of Streets et al. (2006) than to Streets et al. (2003) or Wang et al. (2005). The observed CO/NOy ratio agrees better with inventories. Further analysis suggests that such comparisons may shed some light on the quality of emission inventories, but quantification of any error requires more extensive measurements over longer period and larger areas, as well as direct characterization of emission sources, especially mobile sources and small boilers. Using black carbon (BC)/CO ratio from the experiment, BC emissions from China are estimated at about 1300 Gg (109 g)/yr, but could be as high as 2600 Gg/yr.

  9. In-Situ Mechanical Property Evaluation of Dielectric Ceramics in Multilayer Capacitors

    SciTech Connect

    Wereszczak, A.A.; Riester, L.; Breder, K.

    2000-04-03

    The Young's modulus, hardness, and fracture toughness of barium titanate dielectric ceramics in three commercially available multilayer capacitors (MLCs) were measured in-situ using indentation and a mechanical properties microprobe. The three MLCs were equivalent in size (0805), capacitance (0.1 uF) and dielectric type (X7R). The Young's modulus and hardness of the dielectric ceramics in the three MLCs were similar, while there were statistically significant differences in their fracture toughnesses. The results provide insight into the assessment of MLC mechanical reliability, and show that equivalent electrical MLC rating is not necessarily a guarantee that the dielectric ceramics in them will exhibit equivalent mechanical performance.

  10. In Situ Thermal Characterization of Cooling/Crystallising Lavas During Rheology Measurement.

    NASA Astrophysics Data System (ADS)

    Kolzenburg, S.; Giordano, D.; Cimarelli, C.; Dingwell, D. B.

    2015-12-01

    Transport properties of silicate melts at super-liquidus temperatures are reasonably well understood. Migration and transport of silicate melts in the earth's crust and at its surface generally occur at sub-liquidus temperature regimes where they are subject to non-isothermal and non-equilibrium crystallization. To date, rheological data at sub-liquidus temperatures are scarce. In such dynamic situations heat capacities, latent heats of phase changes, viscous heating, thermal advection and thermal inertia of the apparatus are all potential factors in determining the thermal regime. Yet thermal characterisation of non- equilibrium conditions are absent, hampered by the inconvenience of recording in situ sample temperature during dynamic rheological measurements. Here we present a new experimental setup for in situ sample temperature monitoring in high temperature rheometry. We overcome the limitation of hardwired thermocouples during sample deformation by employing wireless data transmitters directly mounted onto the rotating spindle, immersed in the sample. This adaptation enables in situ, real-time, observations of the thermal regime of crystallising, deforming lava samples under the transient and non-equilibrium crystallization conditions expected in lava flows in nature. We present the apparatus calibration procedure, assess the experimental uncertainty in viscosity measurements and discuss experimental data investigating the dynamic, rheologic and thermal evolution of lavas in both temperature step and continuous cooling experiments.

  11. Tracking aerosol plumes: lidar, modeling, and in situ measurement

    NASA Astrophysics Data System (ADS)

    Calhoun, Ron J.; Heap, Robert; Sommer, Jeffrey; Princevac, Marko; Peccia, Jordan; Fernando, H.

    2004-09-01

    The authors report on recent progress of on-going research at Arizona State University for tracking aerosol plumes using remote sensing and modeling approaches. ASU participated in a large field experiment, Joint Urban 2003, focused on urban and suburban flows and dispersion phenomena which took place in Oklahoma City during summer 2003. A variety of instruments were deployed, including two Doppler-lidars. ASU deployed one lidar and the Army Research deployed the other. Close communication and collaboration has produced datasets which will be available for dual Doppler analysis. The lidars were situated in a way to provide insight into dynamical flow structures caused by the urban core. Complementary scanning by the two lidars during the July 4 firework display in Oklahoma City demonstrated that smoke plumes could be tracked through the atmosphere above the urban area. Horizontal advection and dispersion of the smoke plumes were tracked on two horizontal planes by the ASU lidar and in two vertical planes with a similar lidar operated by the Army Research Laboratory. A number of plume dispersion modeling systems are being used at ASU for the modeling of plumes in catastrophic release scenarios. Progress using feature tracking techniques and data fusion approaches is presented for utilizing single and dual radial velocity fields from coherent Doppler lidar to improve dispersion modeling. The possibility of producing sensor/computational tools for civil and military defense applications appears worth further investigation. An experiment attempting to characterize bioaerosol plumes (using both lidar and in situ biological measurements) associated with the application of biosolids on agricultural fields is in progress at the time of writing.

  12. Correlations between the in situ acoustic properties and geotechnical parameters of sediments in the Yellow Sea, China

    NASA Astrophysics Data System (ADS)

    Liu, Baohua; Han, Tongcheng; Kan, Guangming; Li, Guanbao

    2013-11-01

    Knowledge about the marine sediment acoustic properties is a key to understanding wave propagation in sediments and is very important for military oceanography and ocean engineering. We developed a hydraulic-drived self-contained in situ sediment acoustic measurement system, and measured for the first time the in situ acoustic properties of sediments on 78 stations in the Yellow Sea, China, by employing this system. The relationships between the in situ measured acoustic properties and the onboard or laboratory determined geotechnical parameters were analyzed. Porosity was found to be the dominant factor in reducing velocity in a quadratic fashion; velocity showed an increment with bulk density and a decrement with mean grain size and clay content both with a nonlinear dependence; acoustic attenuation showed a bell-shaped correlation with porosity and mean grain size but reduced with clay content of the sediments. The attenuation results indicate that intergrain friction rather than viscous interactions between pore fluid and solid grains is the dominant loss mechanism in our marine sediments. The relationships established would be used to predict the geotechnical parameters from in situ measured acoustic properties and vice versa, as well as being an indicator of the seafloor processes, potential gas bubbles hazard and gas hydrates resources or other suitable targets of acoustic surveys.

  13. Huygens Probe In-Situ Measurements : An Update

    NASA Astrophysics Data System (ADS)

    Lorenz, Ralph D.

    2015-04-01

    The global Titan perspective afforded by ongoing Cassini observations, and prospects for future in-situ exploration, have prompted a re-examination of Huygens data, yielding a number of recent new results. Gravity waves have been detected (Lorenz, Ferri and Young, Icarus, 2014) in the HASI descent temperature data, with ~2K amplitude. These waves are seen above about 60km, and analysis suggests they may therefore be controlled by interaction of upward-propagating waves with the zonal wind field. A curious cessation of detection of sound pulses by a Surface Science Package ultrasound instrument about 15 minutes after the probe landed appears to be best explained (Lorenz et al., Planetary and Space Science, 2014) by an accumulation of polyatomic vapors such as ethane, sweated out of the ground by the warm probe. Such gases have high acoustic attenuation, and were independently measured by the probe GCMS. The Huygens probe carried two radar altimeters. While their principal function was merely to trigger observation sequences at specific altitudes on the science instruments, the surface range history, and the Automatic Gain Control (AGC) housekeeping data, provide some useful information on Titan's surface (Lorenz et al., submitted). Small-scale topographic variations, and the surface radar reflectivity characteristics implied by the AGC variation with height, are discussed. A new integrated timeline product, which arranges second-by-second measurements from several Huygens sensors on a convenient, common tabulation, has been recently archived on the PDS Atmospheres node. Finally, a troubling discrepancy exists between radio occultation and infrared soundings from Cassini, and Huygens methane and temperature measurements in the lower stratosphere. The interdependence of these parameters will be discussed. In particular the possible role of the assumed probe mass history (depending on the unmeasured ablation from the heat shield) and the assumed zonal wind profile on

  14. In situ measurements of thermospheric composition, temperature, and winds by mass spectrometry

    NASA Technical Reports Server (NTRS)

    Spencer, N. W.; Carignan, G. R.

    1988-01-01

    Mass spectrometry, in which a beam of electrons ionizes a sample of atmospheric gas and then analyses the ions thus produced to determine the concentration of each species in the sample, is presently evaluated as a basis for the study of earth atmosphere and other planetary atmospheres' properties. Recent applications of in situ mass spectrometry have measured thermospheric neutral gas composition, temperatures, and winds, with a spatial resolution sufficiently high to reveal previously unsuspected atmospheric variability. It is expected that analyses of these data will lead to a more detailed understanding of the deposition processes governing the thermosphere's highly variable structure.

  15. MEASURING THE PLASTIC RESPONSE IN POLYCRSYTALLINE MATERIALS USING IN-SITU X-RAY DIFFRACTION

    SciTech Connect

    Hawreliak, J; Butterfield, M; El-Dasher, B; McNaney, J; Lorenzana, H

    2008-10-01

    The insight provided by ultra-fast lattice level measurements during high strain rate high pressure experiments is key to understanding kinetic material properties like plasticity. In-situ x-ray diffraction provides a diagnostic technique which can be used to study the governing physical phenomena of plasticity at the relevant time and spatial scale. Here we discuss the recent development of a geometry capable of investigating plasticity in polycrystalline foils. We also present some preliminary data of investigations into shock compressed rolled copper foils.

  16. The international soil moisture network: A data hosting facility for global in situ soil moisture measurements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In situ measurements of soil moisture are invaluable for calibrating and validating land surface models and satellite-based soil moisture retrievals. In addition, long-term time series of in situ soil moisture measurements themselves can reveal trends in the water cycle related to climate or land co...

  17. Novel Sensor for the In Situ Measurement of Uranium Fluxes

    SciTech Connect

    Hatfield, Kirk

    2015-02-10

    The goal of this project was to develop a sensor that incorporates the field-tested concepts of the passive flux meter to provide direct in situ measures of flux for uranium and groundwater in porous media. Measurable contaminant fluxes [J] are essentially the product of concentration [C] and groundwater flux or specific discharge [q ]. The sensor measures [J] and [q] by changes in contaminant and tracer amounts respectively on a sorbent. By using measurement rather than inference from static parameters, the sensor can directly advance conceptual and computational models for field scale simulations. The sensor was deployed in conjunction with DOE in obtaining field-scale quantification of subsurface processes affecting uranium transport (e.g., advection) and transformation (e.g., uranium attenuation) at the Rifle IFRC Site in Rifle, Colorado. Project results have expanded our current understanding of how field-scale spatial variations in fluxes of uranium, groundwater and salient electron donor/acceptors are coupled to spatial variations in measured microbial biomass/community composition, effective field-scale uranium mass balances, attenuation, and stability. The coupling between uranium, various nutrients and micro flora can be used to estimate field-scale rates of uranium attenuation and field-scale transitions in microbial communities. This research focuses on uranium (VI), but the sensor principles and design are applicable to field-scale fate and transport of other radionuclides. Laboratory studies focused on sorbent selection and calibration, along with sensor development and validation under controlled conditions. Field studies were conducted at the Rifle IFRC Site in Rifle, Colorado. These studies were closely coordinated with existing SBR (formerly ERSP) projects to complement data collection. Small field tests were conducted during the first two years that focused on evaluating field-scale deployment procedures and validating sensor performance under

  18. Satellite and in-situ derived aerosol optical properties over the TCAP campaign region

    NASA Astrophysics Data System (ADS)

    Chand, D.; Berg, L. K.; Ferrare, R. A.; Barnard, J.; Berkowitz, C. M.; Chapman, E.; Comstock, J. M.; Fast, J. D.; Flynn, C. J.; Hair, J. W.; Hostetler, C. A.; Hubbe, J.; Kassianov, E.; Kluzek, C. D.; Pekour, M. S.; Sedlacek, A. J.; Schmid, B.; Shilling, J. E.; Shinozuka, Y.; Tomlinson, J. M.; Wilson, J. M.; Zelenyuk, A.

    2012-12-01

    The direct radiative effect of natural and anthropogenic aerosol is one of the largest uncertainties in the prediction of climate change at regional and global scales. The uncertainties in atmospheric radiative forcing are in part a result of limited knowledge of aerosol optical properties. In this presentation we discuss in-situ and satellite derived aerosol optical properties obtained within the Two-Column Aerosol Project (TCAP) campaign region, and explore their links with aerosol chemical and physical properties. The TCAP field campaign is designed to provide observations of the size distribution, chemical properties, and optical properties of aerosol within and between two atmospheric columns along the eastern seaboard of the United States. These columns are separated by 200-300 km and were sampled in July 2012 during a summer intensive operation period (IOP) using the U.S. Department of Energy's Gulfstream-1 (G-1) and NASA's B200 aircraft and the surface-based DOE Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF) located at Cape Cod. In contrast to the aircraft IOP, the AMF will be operated continuously until the summer of 2013.The surface observations will test the veracity of cloud and radiative transfer models over a wider range of conditions than can be observed via the short-term aircraft IOPs. In this presentation we will examine the spectral dependence of the aerosol optical properties with a focus on in-situ as well as remote sensing observations during the summer (July) over the TCAP region. We will also use multiple years of observations from MODIS, CALIPSO, and OMI satellite sensors and develop the climatology of aerosol optical depth (AOD), single scattering albedo (SSA) and aerosol layer altitudes to put the TCAP observations into a larger perspective. In addition, in-situ observations of light scattering and absorption coefficients made using the G-1, and AOD and aerosol features derived from the NASA High Spectral Resolution Lidar

  19. In situ stress measurements at the Spent Fuel Test-Climax facility

    SciTech Connect

    Creveling, J.B.; Shuri, F.S.; Foster, K.M.; Mills, S.V.

    1984-05-01

    The status of the following studies is given: in situ state of stress; stress gradient into rib from south heater drift; pillar stresses; and rock deformational properties. 11 references, 38 figures, 12 tables.

  20. Feasibility of an in situ measurement device for bubble size and distribution

    PubMed Central

    Maciejak, Walter; Darnell, Branson; Lester, Michael; Pollack, Michael

    2007-01-01

    The feasibility of in situ measurement device for bubble size and distribution was explored. A novel in situ probe measurement system, the EnviroCam™, was developed. Where possible, this probe incorporated strengths, and minimized weaknesses of historical and currently available real-time measurement methods for bubbles. The system was based on a digital, high-speed, high resolution, modular camera system, attached to a stainless steel shroud, compatible with standard Ingold ports on fermenters. Still frames and/or video were produced, capturing bubbles passing through the notch of the shroud. An LED light source was integral with the shroud. Bubbles were analyzed using customized commercially available image analysis software and standard statistical methods. Using this system, bubble sizes were measured as a function of various operating parameters (e.g., agitation rate, aeration rate) and as a function of media properties (e.g., viscosity, antifoam, cottonseed flour, and microbial/animal cell broths) to demonstrate system performance and its limitations. For selected conditions, mean bubble size changes qualitatively compared favorably with published relationships. Current instrument measurement capabilities were limited primarily to clear solutions that did not contain large numbers of overlapping bubbles. PMID:17566786

  1. Kinematic analysis of in situ measurement during chemical mechanical planarization process.

    PubMed

    Li, Hongkai; Wang, Tongqing; Zhao, Qian; Meng, Yonggang; Lu, Xinchun

    2015-10-01

    Chemical mechanical planarization (CMP) is the most widely used planarization technique in semiconductor manufacturing presently. With the aid of in situ measurement technology, CMP tools can achieve good performance and stable productivity. However, the in situ measurement has remained unexplored from a kinematic standpoint. The available related resources for the kinematic analysis are very limited due to the complexity and technical secret. In this paper, a comprehensive kinematic analysis of in situ measurement is provided, including the analysis model, the measurement trajectory, and the measurement time of each zone of wafer surface during the practical CMP process. In addition, a lot of numerical calculations are performed to study the influences of main parameters on the measurement trajectory and the measurement velocity variation of the probe during the measurement process. All the efforts are expected to improve the in situ measurement system and promote the advancement in CMP control system.

  2. Kinematic analysis of in situ measurement during chemical mechanical planarization process

    SciTech Connect

    Li, Hongkai; Wang, Tongqing; Zhao, Qian; Meng, Yonggang; Lu, Xinchun

    2015-10-15

    Chemical mechanical planarization (CMP) is the most widely used planarization technique in semiconductor manufacturing presently. With the aid of in situ measurement technology, CMP tools can achieve good performance and stable productivity. However, the in situ measurement has remained unexplored from a kinematic standpoint. The available related resources for the kinematic analysis are very limited due to the complexity and technical secret. In this paper, a comprehensive kinematic analysis of in situ measurement is provided, including the analysis model, the measurement trajectory, and the measurement time of each zone of wafer surface during the practical CMP process. In addition, a lot of numerical calculations are performed to study the influences of main parameters on the measurement trajectory and the measurement velocity variation of the probe during the measurement process. All the efforts are expected to improve the in situ measurement system and promote the advancement in CMP control system.

  3. Savannah River Site Experiences in In Situ Field Measurements of Radioactive Materials

    SciTech Connect

    Moore, F.S.

    1999-10-07

    This paper discusses some of the field gamma-ray measurements made at the Savannah River Site, the equipment used for the measurements, and lessons learned during in situ identification and characterization of radioactive materials.

  4. Preservation properties of in situ modified CaCO3-chitosan composite coatings.

    PubMed

    Sun, Tong; Hao, Wen-ting; Li, Jian-rong; Dong, Zhi-jian; Wu, Chao-ling

    2015-09-15

    To improve the dispersibility, hydrophilia constraints of primitive particle size, and reduce the economic cost, in situ modified CaCO3-chitosan composite coatings were prepared by tape-casting with different modifiers. The coating structures were characterised, and the preservation properties of the coatings were evaluated by fresh indices of Sciaenops ocellatus. The results revealed that the coatings were homogeneous and compact when the in situ modifier was sodium stearate. Besides, the amide I group of chitosan disappeared and hydrogen bonds were formed between the nano-CaCO3 and the chitosan. Meanwhile, the preservation effects to S. ocellatus of the coatings modified in situ by sodium stearate and sodium citrate were better. This was because the coatings effectively prevented oxygen and bacteria from reaching S. ocellatus, and thus inhibited the degradation of the proteins and lipids. The in situ modified method is conducive to chitosan coating properties, which will be widely used in the food preservation field.

  5. In situ acoustic and laboratory ultrasonic sound speed and attenuation measured in heterogeneous soft seabed sediments: Eel River shelf, California

    USGS Publications Warehouse

    Gorgas, T.J.; Wilkens, R.H.; Fu, S.S.; Neil, Frazer L.; Richardson, M.D.; Briggs, K.B.; Lee, H.

    2002-01-01

    We compared in situ and laboratory velocity and attenuation values measured in seafloor sediments from the shallow water delta of the Eel River, California. This region receives a substantial volume of fluvial sediment that is discharged annually onto the shelf. Additionally, a high input of fluvial sediments during storms generates flood deposits that are characterized by thin beds of variable grain-sizes between the 40- and 90-m isobaths. The main objectives of this study were (1) to investigate signatures of seafloor processes on geoacoustic and physical properties, and (2) to evaluate differences between geoacoustic parameters measured in situ at acoustic (7.5 kHz) and in the laboratory at ultrasonic (400 kHz) frequencies. The in situ acoustic measurements were conducted between 60 and 100 m of water depth. Wet-bulk density and porosity profiles were obtained to 1.15 m below seafloor (m bsf) using gravity cores of the mostly cohesive fine-grained sediments across- and along-shelf. Physical and geoacoustic properties from six selected sites obtained on the Eel margin revealed the following. (1) Sound speed and wet-bulk density strongly correlated in most cases. (2) Sediment compaction with depth generally led to increased sound speed and density, while porosity and in situ attenuation values decreased. (3) Sound speed was higher in coarser- than in finer-grained sediments, on a maximum average by 80 m s-1. (4) In coarse-grained sediments sound speed was higher in the laboratory (1560 m s-1) than in situ (1520 m s-1). In contrast, average ultrasonic and in situ sound speed in fine-grained sediments showed only little differences (both approximately 1480 m s-1). (5) Greater attenuation was commonly measured in the laboratory (0.4 and 0.8 dB m-1 kHz-1) than in situ (0.02 and 0.65 dB m-1 kHz-1), and remained almost constant below 0.4 m bsf. We attributed discrepancies between laboratory ultrasonic and in situ acoustic measurements to a frequency dependence of

  6. Development of an in situ thermal conductivity measurement system for exploration of the shallow subsurface

    NASA Astrophysics Data System (ADS)

    Chirila, Marian Andrei; Christoph, Benjamin; Vienken, Thomas; Dietrich, Peter; Bumberger, Jan

    2016-06-01

    In this study, we attempted to develop an in situ thermal conductivity measurement system that can be used for subsurface thermal exploration. A new thermal probe was developed for mapping both the spatial and temporal variability of thermal conductivity, via direct push methods in the unconsolidated shallow subsurface. A robust, hollow cylindrical probe was constructed and its performance was tested by carrying out thermal conductivity measurements on materials with known properties. The thermal conductivity of the investigated materials can be worked out by measuring the active power consumption (in alternating current system) and temperature of the probe over fixed time intervals. A calibration method was used to eliminate any undesired thermal effects regarding the size of the probe, based on mobile thermal analyzer thermal conductivity values. Using the hollow cylindrical probe, the thermal conductivity results obtained had an error of less than 2.5% for solid samples (such as Teflon, Agar Jelly and Nylatron).

  7. Time-Resolved In Situ Measurements During Rapid Alloy Solidification: Experimental Insight for Additive Manufacturing

    DOE PAGESBeta

    McKeown, Joseph T.; Zweiacker, Kai; Liu, Can; Coughlin, Daniel R.; Clarke, Amy J.; Baldwin, J. Kevin; Gibbs, John W.; Roehling, John D.; Imhoff, Seth D.; Gibbs, Paul J.; et al

    2016-01-27

    In research and industrial environments, additive manufacturing (AM) of metals and alloys is becoming a pervasive technology, though significant challenges remain before widespread implementation of AM can be realized. In situ investigations of rapid alloy solidification with high spatial and temporal resolutions can provide unique experimental insight into microstructure evolution and kinetics that are relevant for AM processing. Hypoeutectic thin-film Al–Cu and Al–Si alloys were investigated using dynamic transmission electron microscopy to monitor pulsed-laser-induced rapid solidification across microsecond timescales. Solid–liquid interface velocities measured from time-resolved images revealed accelerating solidification fronts in both alloys. We observed microstructure evolution, solidification product, andmore » presence of a morphological instability at the solid–liquid interface in the Al–4 at.%Cu alloy are related to the measured interface velocities and small differences in composition that affect the thermophysical properties of the alloys. These time-resolved in situ measurements can inform and validate predictive modeling efforts for AM.« less

  8. Radiation Transmission Properties of In-Situ Materials

    NASA Technical Reports Server (NTRS)

    Heilbronn, L.; Townsend, L. W.; Cucinotta, F.; Kim, M. Y.; Miller, J.; Singleterry, R.; Thibeault, S.; Wilson, J.; Zeitlin, C. J.

    2001-01-01

    The development of a permanent human presence in space is a key element of NASA's strategic plan for the Human Exploration and Development of Space (HEDS). The habitation of the International Space Station (ISS) is one near-term HEDS objective; the exploration and settlement of the moon and Mars are long-term goals of that plan. Achieving these goals requires maintaining the health and safety of personnel involved in such space operations at a high level, while at the same time reducing the cost of those operations to a reasonable level. Among the limiting factors to prolonged human space operations are the health risks from exposure to the space ionizing radiation environment. In order to keep the risk of radiation induced cancer at acceptable levels, it is necessary to provide adequate shielding from the ionizing radiation environment. The research presented here is theoretical and ground-based experimental study of the neutron production from interactions of GCR-like particles in various shielding components. An emphasis is placed here on research that will aid in the development of in-situ resource utilization. The primary goal of the program is to develop an accurate neutron-production model that is relevant to the NASA HEDS program of designing technologies that will be used in the development of effective shielding countermeasures. A secondary goal of the program is the development of an experimental data base of neutron production cross sections and thick-target yields which will aid model development.

  9. Property Measurement

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Van is used by Land Inventory Systems to measure and map property for tax assessment purposes. It is adapted from navigation system of the Lunar Rover wheeled vehicle in which moon-exploring astronauts traveled as much as 20 miles from their Lunar Module base. Astronauts had to know their precise position so that in case of emergency they could take the shortest route back. Computerized navigational system kept a highly accurate record of the directional path providing continuous position report. Distance measuring subsystem was a more accurate counterpart of automobile odometer system counts revolutions of wheels and encoders generate electrical pulses for each fractional revolution and the computer analyzed the pulses to determine the distance traveled in a given direction.

  10. In-situ dust measurements by a lunar lander

    NASA Astrophysics Data System (ADS)

    Srama, Ralf; Sternovsky, Zoltan; Horanyi, Mihaly; Gruen, Eberhard; Krueger, Harald; Laufer, Rene; Roeser, Hans-Peter; Postberg, Frank; Kempf, Sascha; Moragas-Klostermeyer, Georg; Mocker, Anna; Fiege, Katherina; Li, Yanwei

    2012-07-01

    Charged dust grains on the lunar surface impact our future exploration of the moon. Serious problems for exploration activities were revealed by the Apollo missions. Dust shows strong adhesion to equipment and clothes and makes breathing difficult within a spacecraft. The micron- and submicron sized grains are embedded in the lunar plasma environment and their physical properties determine their dynamics. The solar wind, UV light and shadows lead to temporal effects in plasma densities and dust grain charging states. The dust populations relevant for the processes on the surface are: interplanetary and interstellar dust, levitated dust and, especially, dust ejecta generated by primary impacts on the surface. A dust instrument on the surface shall distinguish the three populations and characterize their charging state, size, speed and directionality distribution. Dust measurements shall be performed in conjunction with surface plasma and surface electric field characterizations.

  11. Burst mode trigger of STEREO in situ measurements

    NASA Astrophysics Data System (ADS)

    Jian, L. K.; Russell, C. T.; Luhmann, J. G.; Curtis, D.; Schroeder, P.

    2013-06-01

    Since the launch of the STEREO spacecraft, the in situ instrument suites have continued to modify their burst mode trigger in order to optimize the collection of high-cadence magnetic field, solar wind, and suprathermal electron data. This report reviews the criteria used for the burst mode trigger and their evolution with time. From 2007 to 2011, the twin STEREO spacecraft observed 236 interplanetary shocks, and 54% of them were captured by the burst mode trigger. The capture rate increased remarkably with time, from 30% in 2007 to 69% in 2011. We evaluate the performance of multiple trigger criteria and investigate why some of the shocks were missed by the trigger. Lessons learned from STEREO are useful for future missions, because the telemetry bandwidth needed to capture the waveforms of high frequency but infrequent events would be unaffordable without an effective burst mode trigger.

  12. Properties of n-Ge epilayer on Si substrate with in-situ doping technology

    NASA Astrophysics Data System (ADS)

    Shi-Hao, Huang; Cheng, Li; Cheng-Zhao, Chen; Chen, Wang; Wen-Ming, Xie; Shu-Yi, Lin; Ming, Shao; Ming-Xing, Nie; Cai-Yun, Chen

    2016-06-01

    The properties of n-Ge epilayer deposited on Si substrate with in-situ doping technology in a cold-wall ultrahigh vacuum chemical vapor deposition (UHVCVD) system are investigated. The growth temperature of ˜500 °C is optimal for the n-Ge growth in our equipment with a phosphorus concentration of ˜1018 cm-3. In the n-Ge epilayer, the depth profile of phosphorus concentration is box-shaped and the tensile strain of 0.12% confirmed by x-ray diffraction measurement is introduced which results in the red shift of the photoluminescence. The enhancements of photoluminescence intensity with the increase of the doping concentration are observed, which is consistent with the modeling of the spontaneous emission spectrum for direct transition of Ge. The results are of significance for guiding the growth of n-Ge epilayer with in-situ doping technology. Project supported by the National Basic Research Program of China (Grant No. 2013CB632103), the National Key Technology Support Program of China (Grant No. 2015BAF24B01), the Natural Science Foundation of Fujian Province of China (Grant No. 2016J05147), the Key Sci-Tech Research and Development Platform of Fujian Province, China (Grant No. 2014H2002), the Provincial University Foundation of Fujian Province, China (Grant No. JK2013030), the Educational Youth Key Foundation of Fujian Province, China (Grant No. JA13210), and the Scientific Research Fund of Fujian University of Technology, China (Grant No. GY-Z14073).

  13. Versatile variable temperature insert at the DEIMOS beamline for in situ electrical transport measurements.

    PubMed

    Joly, L; Muller, B; Sternitzky, E; Faullumel, J G; Boulard, A; Otero, E; Choueikani, F; Kappler, J P; Studniarek, M; Bowen, M; Ohresser, P

    2016-05-01

    The design and the first experiments are described of a versatile cryogenic insert used for its electrical transport capabilities. The insert is designed for the cryomagnet installed on the DEIMOS beamline at the SOLEIL synchrotron dedicated to magnetic characterizations through X-ray absorption spectroscopy (XAS) measurements. This development was spurred by the multifunctional properties of novel materials such as multiferroics, in which, for example, the magnetic and electrical orders are intertwined and may be probed using XAS. The insert thus enables XAS to in situ probe this interplay. The implementation of redundant wiring and careful shielding also enables studies on operating electronic devices. Measurements on magnetic tunnel junctions illustrate the potential of the equipment toward XAS studies of in operando electronic devices.

  14. A new tensile stage for in situ electron microscopy examination of the mechanical properties of 'superelastic' specimens

    SciTech Connect

    Dragnevski, Kalin I.; Fairhead, Trevor W.; Balsod, Rik; Donald, Athene M.

    2008-12-15

    We have developed a novel tensile stage that can be used for in situ electron microscopy examination of the mechanical properties of ''superelastic'' materials. In our stage, one of the specimen clamps is replaced by a cylindrical roller, which when driven by a motor can easily stretch (''roll on'') any specimen irrespective of its plastic properties. We have used the so-called Roll-o-meter in the study of the tensile behavior of two different film formed latex formulations, here referred to as standard and novel. We find that the values of the tensile strength and extension to break of the studied systems, measured by using the Roll-o-meter, are similar to those measured by a Hounsfield tensile testing machine outside the microscope chamber. Further, in situ environmental scanning electron microscopy examination of the deformation and failure of the lattices revealed that the standard specimens exhibit a more ductile behavior, compared to the novel ones.

  15. Comparison of vertical aerosol extinction coefficients from in-situ and LIDAR measurements

    NASA Astrophysics Data System (ADS)

    Rosati, B.; Herrmann, E.; Bucci, S.; Fierli, F.; Cairo, F.; Gysel, M.; Tillmann, R.; Größ, J.; Gobbi, G. P.; Di Liberto, L.; Di Donfrancesco, G.; Wiedensohler, A.; Weingartner, E.; Virtanen, A.; Mentel, T. F.; Baltensperger, U.

    2015-07-01

    Vertical profiles of aerosol optical properties were explored in a case study near the San Pietro Capofiume (SPC) ground station during the PEGASOS Po Valley campaign in the summer of 2012. A Zeppelin NT airship was employed to investigate the effect of the dynamics of the planetary boundary layer at altitudes between ~ 50-800 m above ground. Determined properties included the aerosol size distribution, the hygroscopic growth factor, the effective index of refraction and the light absorption coefficient. The first three parameters were used to retrieve the light scattering coefficient. Simultaneously, direct measurements of both the scattering and absorption coefficient were carried out at the SPC ground station. Additionally, a LIDAR system provided aerosol extinction coefficients for a vertically resolved comparison between in-situ and remote sensing results. First, the airborne results at low altitudes were validated with the ground measurements. Agreement within approximately ±25 and ±20% was found for the dry scattering and absorption coefficient, respectively. The single scattering albedo, ranged between 0.83 to 0.95, indicating the importance of the absorbing particles in the Po Valley region. A clear layering of the atmosphere was observed during the beginning of the flight (until ~ 10 local time) before the mixed layer (ML) was fully developed. Highest extinction coefficients were found at low altitudes, in the new ML, while values in the residual layer, which could be probed at the beginning of the flight at elevated altitudes, were lower. At the end of the flight (after ~ 12 local time) the ML was fully developed, resulting in constant extinction coefficients at all altitudes measured on the Zeppelin NT. LIDAR results captured these dynamic features well and good agreement was found for the extinction coefficients compared to the in-situ results, using fixed LIDAR ratios (LR) between 30 and 70 sr for the altitudes probed with the Zeppelin. These LR are

  16. In-Situ Measurement of Hall Thruster Erosion Using a Fiber Optic Regression Probe

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt; Korman, Valentin

    2009-01-01

    One potential life-limiting mechanism in a Hall thruster is the erosion of the ceramic material comprising the discharge channel. This is especially true for missions that require long thrusting periods and can be problematic for lifetime qualification, especially when attempting to qualify a thruster by analysis rather than a test lasting the full duration of the mission. In addition to lifetime, several analytical and numerical models include electrode erosion as a mechanism contributing to enhanced transport properties. However, there is still a great deal of dispute over the importance of erosion to transport in Hall thrusters. The capability to perform an in-situ measurement of discharge channel erosion is useful in addressing both the lifetime and transport concerns. An in-situ measurement would allow for real-time data regarding the erosion rates at different operating points, providing a quick method for empirically anchoring any analysis geared towards lifetime qualification. Erosion rate data over a thruster s operating envelope would also be useful in the modeling of the detailed physics inside the discharge chamber. There are many different sensors and techniques that have been employed to quantify discharge channel erosion in Hall thrusters. Snapshots of the wear pattern can be obtained at regular shutdown intervals using laser profilometry. Many non-intrusive techniques of varying complexity and sensitivity have been employed to detect the time-varying presence of erosion products in the thruster plume. These include the use quartz crystal microbalances, emission spectroscopy, laser induced flourescence, and cavity ring-down spectroscopy. While these techniques can provide a very accurate picture of the level of eroded material in the thruster plume, it is more difficult to use them to determine the location from which the material was eroded. Furthermore, none of the methods cited provide a true in-situ measure of erosion at the channel surface while

  17. In situ-based effects measures: considerations for improving methods and approaches.

    PubMed

    Liber, Karsten; Goodfellow, William; den Besten, Pieter; Clements, Will; Galloway, Tamara; Gerhardt, Almut; Green, Andrew; Simpson, Stuart

    2007-04-01

    In situ-based effects measures have gained increased acceptance as a means to improve the link between cause and effect in aquatic ecotoxicological studies. These approaches have primarily been employed where more conventional laboratory tests with field collected samples and routine in-field community surveys have failed to provide reasonable answers with respect to causes of toxicity, primary routes of contaminant exposure, and what constitutes ecotoxicologically relevant contaminant levels, at least at a site-specific level. One of the main advantages provided by in situ tests compared to more conventional field-based monitoring approaches is that they provide better control over stressor exposure to a defined population of test animals under natural or near-natural field conditions. In situ techniques can also be used to avoid artifacts related to sampling, transport and storage of contaminated water and sediment intended for laboratory-based toxicity assessment. In short, they can reduce the need for laboratory to field extrapolation and, when conducted properly, in situ tests can provide improved diagnostic ability and high ecological relevance. This paper provides suggestions and considerations for designing in situ studies, choosing test species and test endpoints, avoiding or minimizing test artifacts, best addressing some of the limitations of in situ test techniques, and generally improving the overall quality of the in situ approach chosen.

  18. DOE capabilities for in-situ characterization and monitoring of formation properties in the vadose zone

    SciTech Connect

    Hearst, J.R.; Brodeur, J.R.; Koizumi, C.J.; Conaway, J.G.; Mikesell, J.L.; Nelson, P.H.; Stromswold, D.C.; Wilson, R.D.

    1993-09-01

    The DOE Environmental Restoration (ER) Program faces the difficult task of characterizing the properties of the subsurface and identifying and mapping a large number of contaminants at landfills, surface disposal areas, spill sites, nuclear waste tanks, and subsurface contaminant plumes throughout the complex of DOE facilities. Geophysical borehole logs can measure formation properties such as bulk density, water content, and lithology, and can quantitatively analyze for radionuclides and such elements as chlorine and heavy metals. Since these measurements can be replaced as desired, they can be used for both initial characterization and monitoring of changes in contaminant concentration and water content (sometimes linked to contaminant migration), at a fraction of the cost of conventional sampling. The techniques develop at several DOE laboratories, and the experience that the authors have gained in making in-situ measurements in the vadose zone, are applicable to problems at many other DOE sites. Moreover, they can capitalize on existing inventories of boreholes. By building on this experience workers involved in ER projects at those sites should be able to obtain high-quality data at substantial reductions in cost and time.

  19. In-Situ Measurement of Hall Thruster Erosion Using a Fiber Optic Regression Probe

    NASA Technical Reports Server (NTRS)

    Polzink, Kurt A.; Korman, Valentin

    2008-01-01

    One potential life-limiting mechanism in a Hall thruster is the erosion of the ceramic material comprising the discharge channel. This is especially true for missions that require long thrusting periods and can be problematic for lifetime qualification, especially when attempting to qualify a thruster by analysis rather than a test lasting the full duration of the mission. In addition to lifetime, several analytical and numerical models include electrode erosion as a mechanism contributing to enhanced transport properties. However, there is still a great deal of dispute over the importance of erosion to transport in Hall thrusters. The capability to perform an in-situ measurement of discharge channel erosion is useful in addressing both the lifetime and transport concerns. An in-situ measurement would allow for real-time data regarding the erosion rates at different operating points, providing a quick method for empirically anchoring any analysis geared towards lifetime qualification. Erosion rate data over a thruster's operating envelope would also be useful in the modeling of the detailed physics inside the discharge chamber. A recent fundamental sensor development effort has led to a novel regression, erosion, and ablation sensor technology (REAST). The REAST sensor allows for measurement of real-time surface erosion rates at a discrete surface location. The sensor was tested using a linear Hall thruster geometry, which served as a means of producing plasma erosion of a ceramic discharge chamber. The mass flow rate, discharge voltage, and applied magnetic field strength could be varied, allowing for erosion measurements over a broad thruster operating envelope. Results are presented demonstrating the ability of the REAST sensor to capture not only the insulator erosion rates but also changes in these rates as a function of the discharge parameters.

  20. In situ osteoblast mineralization mediates post-injection mechanical properties of osteoconductive material.

    PubMed

    Bialorucki, Callan; Subramanian, Gayathri; Elsaadany, Mostafa; Yildirim-Ayan, Eda

    2014-10-01

    The objective of this study was to understand the temporal relationship between in situ generated calcium content (mineralization) and the mechanical properties of an injectable orthobiologic bone-filler material. Murine derived osteoblast progenitor cells were differentiated using osteogenic factors and encapsulated within an injectable polycaprolactone nanofiber-collagen composite scaffold (PN-COL +osteo) to evaluate the effect of mineralization on the mechanical properties of the PN-COL scaffold. A comprehensive study was conducted using both an experimental and a predictive analytical mechanical analysis for mechanical property assessment as well as an extensive in vitro biological analysis for in situ mineralization. Cell proliferation was evaluated using a PicoGreen dsDNA quantification assay and in situ mineralization was analyzed using both an alkaline phosphatase (ALP) assay and an Alizarin Red stain-based assay. Mineralized matrix formation was further evaluated using energy dispersive x-ray spectroscopy (EDS) and visualized using SEM and histological analyses. Compressive mechanical properties of the PN-COL scaffolds were determined using a confined compression stress-relaxation protocol and the obtained data was fit to the standard linear solid viscoelastic material mathematical model to demonstrate a relationship between increased in situ mineralization and the mechanical properties of the PN-COL scaffold. Cell proliferation was constant over the 21 day period. ALP activity and calcium concentration significantly increased at day 14 and 21 as compared to PN-COL -osteo with undifferentiated osteoblast progenitor cells. Furthermore, at day 21 EDS, SEM and von Kossa histological staining confirmed mineralized matrix formation within the PN-COL scaffolds. After 21 days, compressive modulus, peak stress, and equilibrium stress demonstrate significant increases of 3.4-fold, 3.3-fold, and 4.0-fold respectively due to in situ mineralization. Viscoelastic

  1. In situ attosecond pulse characterization techniques to measure the electromagnetic phase

    NASA Astrophysics Data System (ADS)

    Spanner, M.; Bertrand, J. B.; Villeneuve, D. M.

    2016-08-01

    A number of techniques have been developed to characterize the attosecond emission from high-order-harmonic sources. These techniques are broadly classified as ex situ, where the attosecond pulse train photoionizes a target gas in the presence of an infrared field, and in situ, where the measurement takes place in the medium in which the attosecond pulses are generated. It is accepted that ex situ techniques measure the characteristics of the electromagnetic field, including the phase of the recombination transition moment of the emitting atom or molecule, when the phase of the second medium is known. However, there is debate about whether in situ techniques measure the electromagnetic field, or only the characteristics of the recolliding electron before recombination occurs. We show numerically that in situ measurements are not sensitive to the recombination phase, when implemented in the perturbative regime as originally envisioned, and that they do not measure the electromagnetic phase of the emission.

  2. In situ CTE measurements and damage detection using optical metrology

    NASA Astrophysics Data System (ADS)

    Rajaram, Satish; Cuadra, Jefferson; Saralaya, Raghav; Bartoli, Ivan; Kontsos, Antonios

    2016-02-01

    This paper presents a methodology to make coefficient of thermal expansion measurements through the combined use of two non-contact and full field optical metrology methods including digital image correlation and infrared thermography. In this context, active Infrared Thermography techniques combined with contact and non-contact deformation measurement methods have already been reported to measure materials’ thermal expansion. In addition, such techniques have been reported to be capable to detect surface and subsurface defects from changes in homogenous heat diffusion due to damage. Based on this knowledge, it is hypothesized in this article that the material response induced by thermal loading and quantified by coefficient of thermal expansion measurements could be further used as an indicator of damage. To validate the hypothesis three measurements were performed. The first established the effectiveness of using deformation and thermal full field data for coefficient of thermal expansion measurements. The second intended to demonstrate the advantage of using such full field data in order to provide site-specific measurements of thermal expansion. Finally damage was a priori induced to a metallic specimen, and the measured variations of local CTE confirmed the potential of using the described approach as a means of damage quantification in materials and structures.

  3. Development of ``Smart Sediments'' to Conduct In-Situ Measurements within Mobile Bed Layers

    NASA Astrophysics Data System (ADS)

    Frank, D. P.; Foster, D.; Chou, P.

    2010-12-01

    Observing the motion of sediment beds in nearshore environments has been previously limited by technological capabilities. Experiments utilizing both optical and acoustic techniques have provided great insight into the hydrodynamics within the bottom boundary and mobile bed layers. However, most previous technologies were not capable of in-situ investigations of the morphodynamics within these layers because they are generally thin, within 1-100 grain diameters. In-situ measurements of the mobile bed layer will be made with new state-of-the-art micro-electronic machines (MEM’s). These mobile nodes are 13x11x7 mm and are equipped with tri-axial accelerometers, temperature and pressure sensors, in addition to, a wireless transmitter and micro-processor. In this generation, the ceramic enclosure is comparable in size to coarse gravel. The device has the same physical properties as quartz and should provide significant insight into incipient motion and sediment transport under oscillatory flow fields in the nearshore environment. The mobile nodes will first be tested at a field-scale laboratory wave facility before being used in the nearshore. The morphodynamics of heterogeneous sediments will also be explored. The overarching goal of this project is to enhance the scientific community’s understanding of the hydrodynamics and morphodynamics within the wave-dominated bottom boundary layer environment through technological development of the “smart sediments”. In particular, we seek to test the hypothesis that in unsteady flow where the sediment may be heterogeneous, the incipient motion of a sediment bed results from a combination of the shear stress gradient and pressure gradient. The goal of this presentation is to evaluate the sensors on their physical properties such as moment of inertia and radio frequency transmission.

  4. Metal matrix composite micromechanics - In situ behavior influence on composite properties

    NASA Technical Reports Server (NTRS)

    Murthy, P. L. N.; Hopkins, D. A.; Chamis, C. C.

    1989-01-01

    The influence of in situ fiber and matrix properties (such as in situ matrix strength and the interphase degradation) of high-temperature metal matrix composites (HTMMCs) on the unidirectional stress-strain behavior of the composite is examined using results of a numerical investigation of a SiC/Ti-15-3-3-3 unidirectional composite. It is shown that a reduction of the in situ matrix strength substantially decreases the transverse and the longitudinal tensile/compressive strengths, as well as the in-plane shear strength, of the composite. The interphase degradation affects the behavior in transverse tension/compression drastically; both the ultimate strength and strain showed significant reductions. The higher use temperature results in a reduction in the ultimate strength and in the initial tangential modulus for compression and for in-plane shear loading.

  5. In situ measurements of 137Cs γ-ray emission at very high altitudes using a fully portable detector

    NASA Astrophysics Data System (ADS)

    Balerna, A.; Bernieri, E.; Chiti, M.; Denni, U.; Esposito, A.; Frani, A.; Tullio, V.

    2003-10-01

    In the last few years, significant attention has been given to climate changes on a local and global scale. The chemical composition and physical properties of the cryosphere have been and are widely used as indicators of the past climate changes and present environmental transformations. In this field portable γ-ray spectrometers for in situ radioactivity measurements on glaciers and snowfields are very useful, in particular during ice core drillings and pollution monitoring at high altitudes or in remote areas, where sampling is difficult or impossible. A fully portable γ-ray spectrometer for in situ radioactivity measurements is described and the results of the first measurements performed up to 6400 m a.s.l. are reported and discussed.

  6. Temporal Evolution and Atmospheric Impacts of Tropospheric Volcanic Emissions from In-Situ Measurements and Modelling

    NASA Astrophysics Data System (ADS)

    Roberts, Tjarda

    2010-05-01

    Assessment of the impact of tropospheric volcanic gas and aerosol emissions requires integration of observation and modelling. Knowledge and understanding is rapidly advancing in both areas, particularly due to the development of kinetic plume models of reactive halogen chemistry, and due to recent advances in measurement techniques for collecting in situ measurements of plume physico-chemical properties (i.e. using meteorological balloon and aircraft platforms), as well as a proliferation of remote sensing DOAS measurements. Here, we demonstrate this synergic relationship through model-observation plume studies. Volcanoes are a large natural source of SO2 and sulphate to the atmosphere, as is well demonstrated from both observational and model studies. In a recent study that deployed quasi-Lagrangian balloons in emissions at Kilauea volcano, Hawaii, both H2O(g) and SO2(g) were measured in situ, in the downwind plume. The observations showed periods of both correlation and anti-correlation between SO2 and water-vapour, implying the occurrence of both source and sink processes. Co-emission of volcanic H2O with SO2 accounts for the correlation. We use a thermodynamic model along the plume transect to assess how H2O-sulphate interactions might account for H2O anti-correlation with SO2 within the plume to elucidate in-plume sulphate formation, both near-vent (as predicted by high-T thermodynamic models) and downwind (as predicted by kinetic models). Volcanoes are a source of halogens (HBr, HCl) to the atmosphere, and volcanic plumes are highly reactive zones, not only in the high-temperature region near the vent, but also in the downwind plume where autocatalytic chemistry cycles produce reactive halogens such as BrO, first discovered from DOAS observations. The rapid formation of BrO can be reproduced through modelling which predicts high concentrations (reaching ppbv) on short formation timescales (minutes). Simulations using the PlumeChem model (developed to analyse

  7. A model-based framework for the quality assessment of surface albedo in situ measurement protocols

    NASA Astrophysics Data System (ADS)

    Adams, Jennifer; Gobron, Nadine; Widlowski, Jean-Luc; Mio, Corrado

    2016-09-01

    Satellite-based retrievals of land surface albedo are essential for climate and environmental modelling communities. To be of use, satellite-retrievals are required to comply to given accuracy requirements, mainly achieved through comparison with in situ measurements. Differences between in situ and satellite-based retrievals depend on their actual difference and their associated uncertainties. It is essential that these uncertainties can be computed to properly understand the differences between satellite-based and in situ measurements of albedo, however quantifying the individual contributions of uncertainty is difficult. This study introduces a model-based framework for assessing the quality of in situ albedo measurements. A 3D Monte Carlo Ray Tracing (MCRT) radiative transfer model is used to simulate field measurements of surface albedo, and is able to identify and quantify potential sources of error in the field measurement. Compliance with the World Meteorological Organisation (WMO) requirement for 3% accuracy is tested. 8 scenarios were investigated, covering a range of ecosystem types and canopy structures, seasons, illumination angles and tree heights. Results indicate that height of measurement above the canopy is the controlling factor in accuracy, with each canopy scenario reaching the WMO requirement at different heights. Increasing canopy heterogeneity and tree height noticeably reduces the accuracy, whereas changing seasonality from summer to winter in a deciduous forest increases accuracy. For canopies with a row structure, illumination angle can significantly impact accuracy as a result of shadowing effects. Tests were made on the potential use of multiple in situ measurements, indicating considerably increased accuracy if two or more in situ measurements can be made.

  8. Airborne In Situ and Ground-based Polarimetric Radar Measurements of Tropical Convection in Support of CRYSTAL-FACE

    NASA Technical Reports Server (NTRS)

    Poellot, Michael R.; Kucera, Paul A.

    2004-01-01

    This report describes the work performed by the University of North Dakota (UND) under NASA Grant NAG5-11509, titled Airborne In Situ and Ground-based Polarimetric Radar Measurements of Tropical Convection in Support of CRYSTAL-FACE. This work focused on the collection of data by two key platforms: the UND Citation II research aircraft and the NASA NPOL radar system. The CRYSTAL-FACE (C-F) mission addresses several key issues from the NASA Earth System Enterprise, including the variability of water in the atmosphere, the forcing provided by tropical cirrus and the response of the Earth system to this forcing. In situ measurements and radar observations of tropical convection, cirrus clouds and their environment are core elements of C-F. One of the primary issues that C-F is addressing is the relationship of tropical cirrus anvils to precipitating deep convection. The in situ measurements from C-F are being used to validate remote sensing of Earth-Atmosphere properties, increase our knowledge of upper tropospheric water vapor and its distribution, and increase our knowledge of tropical cirrus cloud morphology and composition. Radar measurements, especially polarimetric diversity observations available fiom the NASA NPOL radar, are providing essential information about the initiation, modulation, and dissipation of convective cores and the generation of associated anvils in tropical convection. Specifically, NPOL radar measurements contain information about convective intensity and its vertical structure for comparison with thermodynamic and kinematic environmental measurements observed from soundings. Because of the polarimetric diversity of MOL, statistics on bulk microphysical properties can be retrieved and compared to the other characteristics of convection and associated cirrus anvils. In summary, the central objectives of this proposal were to deploy the UND Citation research aircraft as an in situ sensing platform for this mission and to provide collaborative

  9. Acoustic backscattering by deepwater fish measured in situ from a manned submersible

    NASA Astrophysics Data System (ADS)

    Benoit-Bird, Kelly J.; Au, Whitlow W. L.; Kelley, Christopher D.; Taylor, Christopher

    2003-02-01

    An outstanding problem in fisheries acoustics is the depth dependence of scattering characteristics of swimbladder-bearing fish, and the effects of pressure on the target strength of physoclistous fish remain unresolved. In situ echoes from deepwater snappers were obtained with a sonar transducer mounted on a manned submersible next to a low-light video camera, permitting simultaneous echo recording and identification of species, fish size and orientation. The sonar system, consisting of a transducer, single board computer, hard disk, and analog-to-digital converter, used a 80 μs, broadband signal (bandwidth 35 kHz, center frequency 120 kHz). The observed relationship between fish length and in situ target strength shows no difference from the relationship measured at the surface. No differences in the species-specific temporal echo characteristics were observed between surface and in situ measures. This indicates that the size and shape of the snappers' swimbladders are maintained both at the surface and at depths of up to 250 m. Information obtained through controlled backscatter measurements of tethered, anesthetized fish at the surface can be applied to free-swimming fish at depth. This is the first published account of the use of a manned submersible to measure in situ scattering from identified, individual animals with known orientations. The distinct advantage of this technique compared with other in situ techniques is the ability to observe the target fish, obtaining accurate species, size, and orientation information.

  10. In-Situ Measurements of Fabric Thickness Evolution During Draping

    SciTech Connect

    Ivanov, D. S.; Van Gestel, C.; Lomov, S. V.; Verpoest, I.

    2011-05-04

    The paper presents results of experimental program aimed at measuring fabric thickening while draping. The thickness evolution is important factor in resin infusion manufacturing where the resultant composite thickness is not controlled. The measurements are conducted by means of laser distance sensors adapted to the picture frame testing. Several carbon fabrics of very different architectures have been tested. Additionally, the pretension of the carbon fabric due to the gripping has been estimated by means of digital image correlation technique and an attempt to discuss the results obtained on different set-ups is made.

  11. A high sampling rate digital holographic imager instrument for the in situ measurements of hydrometeors

    NASA Astrophysics Data System (ADS)

    Kaikkonen, Ville A.; Mäkynen, Anssi J.

    2016-06-01

    A novel digital in-line holographic imaging instrument designed for acquiring properties of individual hydrometeors in situ is presented. The instrument has a large measurement volume of 670 cm3. This combined with fast frame rate imaging and software controlled multi-exposure capabilities results in a representative sampling of rain and snowfall events. Hydrometeors are measured and analyzed from the in-focus images with microscopic resolution, and their 3D locations inside the measurement volume are determined. The instrument is designed to operate in cold climates and to produce reliable measurements also during strong winds. The imaging rate of the instrument was designed to be adequately high to observe the dynamic nature of rain and snow falls. By recording multi-exposure holograms, the effective frame rate can be increased. This allows the measurements of the velocities of the fast-falling hydrometeors. The instrument and the hologram processing are described; as well as results from laboratory tests and the first field measurements are shown. As a result, the resolving power of the instrument was measured to vary between 11 and 18 microns inside the measurement volume near the center of the field-of-view. Velocity vectors were measured both from multi-exposure and high frame rate holograms. The measured velocities ranged from 0.1 to 4 m/s. In addition, the projections of a flat-shaped and rotating snowflake imaged at different locations inside the measurement volume demonstrated the possibility to estimate the shape of the hydrometeor from multiple viewing angles.

  12. Disassembling "evapotranspiration" in-situ with a complex measurement tool

    NASA Astrophysics Data System (ADS)

    Chormanski, Jaroslaw; Kleniewska, Malgorzata; Berezowski, Tomasz; Sporak-Wasilewska, Sylwia; Okruszko, Tomasz; Szatylowicz, Jan; Batelaan, Okke

    2014-05-01

    In this work we present a complex tool for measuring water fluxes in wetland ecosystems. The tool was designed to quantify processes related to interception storage on plants leafs. The measurements are conducted by combining readings from various instruments, including: eddy covariance tower (EC), field spectrometer, SapFlow system, rain gauges above and under canopy, soil moisture probes and other. The idea of this set-up is to provide continuous measurement of overall water flux from the ecosystem (EC tower), intercepted water volume and timing (field spectrometers), through-fall (rain gauges above and under canopy), transpiration (SapFlow), evaporation and soil moisture (soil moisture probes). Disassembling the water flux to the above components allows giving more insight to the interception related processes and differentiates them from the total evapotranspiration. The measurements are conducted in the Upper Biebrza Basin (NE Poland). The study area is part of the valley and is covered by peat soils (mainly peat moss with the exception of areas near the river) and receives no inundations waters of the Biebrza. The plant community of Agrostietum-Carici caninae has a dominant share here creating an up to 0.6 km wide belt along the river. The area is covered also by Caricion lasiocarpae as well as meadows and pastures Molinio-Arrhenatheretea, Phragmitetum communis. Sedges form a hummock pattern characteristic for the sedge communities in natural river valleys with wetland vegetation. The main result of the measurement set-up will be the analyzed characteristics and dynamics of interception storage for sedge ecosystems and a developed methodology for interception monitoring by use spectral reflectance technique. This will give a new insight to processes of evapotranspiration in wetlands and its components transpiration, evaporation from interception and evaporation from soil. Moreover, other important results of this project will be the estimation of energy and

  13. Atmospheric Balloon Swarms for Persistent In-Situ Measurements in Hurricanes

    NASA Astrophysics Data System (ADS)

    Meneghello, G.; Bewley, T.

    2015-12-01

    Real-time measurements within hurricanes are essential to improve forecasts, protect property and save lives. Current methods for obtaining in-situ data, including radar and satellite imagery as well as drop-sondes deployed from repeated aircraft flights above or even within the hurricane itself, are costly, dangerous and limited in duration or resolution. We demonstrate how a swarm of inexpensive, buoyancy-controlled, sensor-laden balloons can be deployed from altitude or from sea-level within a hurricane flow field, and coordinated autonomously in an energetically-efficient fashion to persistently and continuously monitor relevant properties (pressure, humidity, temperature, windspeed) of a hurricane for days at a time. Rather than fighting the gale-force winds in the storm, the strong, predictable stratification of these winds is leveraged to disperse the balloons into a favorable, time-evolving distribution and to follow the hurricane track as it moves. Certain target orbits of interest in the hurricane can be continuously sampled by some balloons, while other balloons make continuous sweeps between the eye and the spiral rain bands. We expect the acquired data to complement current measurement methods and to be instrumental in improving the numerical models' forecast skills.

  14. Summary and analysis of 216 GHz polarimetric measurements of in-situ rain

    NASA Astrophysics Data System (ADS)

    Hedden, Abigail S.; Wikner, David A.; Bradley, Russell W.

    2015-05-01

    The Army Research Laboratory (ARL) has developed a polarimetric frequency-modulated continuous-wave (FMCW) instrumentation radar that has been used to study the polarization and backscatter properties of in-situ rain in the 220 GHz atmospheric window. A summary of the preliminary measurements is presented in this work including an analysis of the co-polarization backscatter and attenuation characteristics measured at 216 GHz. A marginal detection of the copolarization backscatter signature of rain was made during a series of fast-moving, heavy downpour thunderstorm events. A detection limit of -40±3 dB[m2/m3] was found for the VV-polarization cross section per unit volume for rain rates up to 150 mm/hr. Co-polarization (VV- and HH-polarization) attenuation characteristics measured at high rain rates (< 20 mm/hr) were well described by a Joss thunderstorm drop distribution in the high frequency limit, where drop size is much greater than the observation wavelength. Observations at 216 GHz suggest attenuation levels of 8-10 dB/km at rain rates above 20 mm/hr, strengthening previous evidence that attenuation through rain is independent of frequency under high rain rate conditions. Attenuation measurements at lower rain rates (< 20 mm/hr) were qualitatively consistent with both Laws and Parsons and Joss thunderstorm distributions.

  15. Comparisons of Arctic In-Situ Snow and Ice Data with Airborne Passive Microwave Measurements

    NASA Technical Reports Server (NTRS)

    Markus, T.; Cavalien, D. J.; Gasiewski, A.; Sturm, M.; Klein, M.; Maslanik, J.; Stroeve, J.; Heinrichs, J.; Holmgren, J.; Irisov, V.

    2004-01-01

    As part of the AMSR-E sea ice validation campaign in March 2003, aircraft flights over the Arctic sea ice were coordinated with ground measurements of snow and sea ice properties. The surface-based measurements were in the vicinity of Barrow, AK, and at a Navy ice camp located in the Beaufort Sea. The NASA P-3 aircraft was equipped with the NOAA ETL PSR microwave radiometer that has the same frequencies as the AMSR-E sensor. The goal was to validate the standard AMSR-E products ice temperature and snow depth on sea ice. Ground measurements are the only way to validate these parameters. The higher spatial resolution of the PSR instrument (between 30 and 500 m, depending on altitude) enables a better comparison between ground measurements and microwave data because of the expected smaller spatial variability. Maps of PSR data can then be used for further down-scaling to AMSR-E pixel areas. Initial results show a good qualitative agreement between the in-situ snow depths and the PSR data. Detailed studies are underway and latest results will be presented.

  16. New optical paper sensor for in situ measurement of hydrogen sulphide in waters and atmospheres.

    PubMed

    Pla-Tolós, J; Moliner-Martínez, Y; Verdú-Andrés, J; Casanova-Chafer, J; Molins-Legua, C; Campíns-Falcó, P

    2016-08-15

    A novel and low-cost colorimetric sensor for the determination of hydrogen sulphide in environmental samples has been developed. This sensor is based on the immobilization of the reagent N,N-Dimethyl-p-phenylenediamine and FeCl3 in paper support, in which the H2S is adsorbed in order to give rise to the formation of methylene blue as reaction product. The sensor has been applied to determine H2S in water and air samples. Two different sampling systems for H2S caption from the air have been assayed: active and passive sampling. The analytical properties of the different systems have been obtained and compared. The analytical signals, corresponding to the methylene blue, have been obtained measuring the absorbance by conventional reflectance diffuse or using different algorithms for quantifying color intensity. The results obtained with both measurement procedures were comparable, with a detection limit of 1.11 and 1.12mLm(-3) for air samples (active and passive), and 0.5mgL(-1) for water samples. The developed sensor provides good accuracy and precision (RSD<12%) and simplifies significantly the analytical measurements because it avoids the need of preparing derivatization reagents, sample handling and allows in situ measurements. The reaction product obtained is highly stable in this support and no provide any blank signal. Under the optimal conditions, the proposed method exhibit excellent visual sensitivity for the naked eye procedure, making the detection of H2S possible. PMID:27260438

  17. In Situ Measurement and Prediction of Stresses and Strains During Casting of Steel

    NASA Astrophysics Data System (ADS)

    Galles, Daniel; Beckermann, Christoph

    2016-02-01

    Modeling the thermo-mechanical behavior of steel during casting is of great importance for the prediction of distortions and cracks. In this study, an elasto-visco-plastic constitutive law is calibrated with mechanical measurements from casting experiments. A steel bar is solidified in a sand mold and strained by applying a force to bolts that are embedded in the two ends of the bar. The temporal evolutions of the restraint force and the bar's length change are measured in situ. The experiments are simulated by inputting calculated transient temperature fields into a finite element stress analysis that employs the measured forces as boundary conditions. The thermal strain predictions are validated using data from experiments without a restraint. Initial estimates of the constitutive model parameters are obtained from available mechanical test data involving reheated steel specimens. The temperature dependence of the strain rate sensitivity exponent is then adjusted until the measured and predicted length changes of the strained bars agree. The resulting calibrated mechanical property dataset is valid for the high-temperature austenite phase of steel. The data reveal a significantly different mechanical behavior during casting compared to what the stress-strain data from reheated specimens show.

  18. In situ granular charge measurement by free-fall videography

    NASA Astrophysics Data System (ADS)

    Waitukaitis, S. R.; Jaeger, H. M.

    2013-02-01

    We present the design and performance characterization of a new experimental technique for measuring individual particle charges in large ensembles of macroscopic grains. The measurement principle is qualitatively similar to that used in determining the elementary charge by Millikan in that it follows individual particle trajectories. However, by taking advantage of new technology we are able to work with macroscopic grains and achieve several orders of magnitude better resolution in charge to mass ratios. By observing freely falling grains accelerated in a horizontal electric field with a co-falling, high-speed video camera, we dramatically increase particle tracking time and measurement precision. Keeping the granular medium under vacuum, we eliminate air drag, leaving the electrostatic force as the primary source of particle accelerations in the co-moving frame. Because the technique is based on direct imaging, we can distinguish between different particle types during the experiment, opening up the possibility of studying charge transfer processes between different particle species. For the ˜300 μm diameter grains reported here, we achieve an average acceleration resolution of ˜0.008 m/s2, a force resolution of ˜500 pN, and a median charge resolution ˜6× 104 elementary charges per grain (corresponding to surface charge densities ˜1 elementary charges per μm2). The primary source of error is indeterminacy in the grain mass, but with higher resolution cameras and better optics this can be further improved. The high degree of resolution and the ability to visually identify particles of different species or sizes with direct imaging make this a powerful new tool to characterize charging processes in granular media.

  19. In situ granular charge measurement by free-fall videography.

    PubMed

    Waitukaitis, S R; Jaeger, H M

    2013-02-01

    We present the design and performance characterization of a new experimental technique for measuring individual particle charges in large ensembles of macroscopic grains. The measurement principle is qualitatively similar to that used in determining the elementary charge by Millikan in that it follows individual particle trajectories. However, by taking advantage of new technology we are able to work with macroscopic grains and achieve several orders of magnitude better resolution in charge to mass ratios. By observing freely falling grains accelerated in a horizontal electric field with a co-falling, high-speed video camera, we dramatically increase particle tracking time and measurement precision. Keeping the granular medium under vacuum, we eliminate air drag, leaving the electrostatic force as the primary source of particle accelerations in the co-moving frame. Because the technique is based on direct imaging, we can distinguish between different particle types during the experiment, opening up the possibility of studying charge transfer processes between different particle species. For the ∼300 μm diameter grains reported here, we achieve an average acceleration resolution of ∼0.008 m/s(2), a force resolution of ∼500 pN, and a median charge resolution ∼6× 10(4) elementary charges per grain (corresponding to surface charge densities ∼1 elementary charges per μm(2)). The primary source of error is indeterminacy in the grain mass, but with higher resolution cameras and better optics this can be further improved. The high degree of resolution and the ability to visually identify particles of different species or sizes with direct imaging make this a powerful new tool to characterize charging processes in granular media.

  20. First in-situ lattice strains measurements under load at VULCAN

    SciTech Connect

    An, Ke; Skorpenske, Harley David; Stoica, Alexandru Dan; Wang, Xun-Li; Cakmak, Ercan

    2011-01-01

    The engineering materials diffractometer, VULCAN, at the Spallation Neutron Source began commissioning on June 26, 2009. This instrument is designed for materials science and engineering studies. In situ lattice strain measurements of a model metallic material under monotonic tensile load have been performed on VULCAN. The tensile load was applied under two different strain rates, and neutron diffraction measurements were carried out in both high-intensity and high-resolution modes. These experiments demonstrated VULCAN's in situ study capability of deformation behaviors even during the early phases of commissioning.

  1. Assessment of accuracy of in-situ methods for measuring building-envelope thermal resistance

    SciTech Connect

    Fang, J.B.; Grot, R.A.; Park, H.S.

    1986-03-01

    A series of field and laboratory tests were conducted to evaluate the accuracy of in-situ thermal-resistance-measurement techniques. The results of thermal-performance evaluation of the exterior walls of six thermal mass test houses situated in Gaithersburg, Maryland are presented. The wall construction of these one-room houses includes insulated light-weight wood frame, uninsulated light-weight wood frame, insulated masonry with outside mass, uninsulated masonry, log, and insulated masonry with inside mass. In-situ measurements of heat transfer through building envelopes were made with heat flux transducers and portable calorimeters.

  2. Magnetic Susceptibility Measurements for in Situ Characterization of Lunar Soil

    NASA Technical Reports Server (NTRS)

    Oder, R. R.

    1992-01-01

    Magnetic separation is a viable method for concentration of components of lunar soils and rocks for use as feedstocks for manufacture of metals, oxygen, and for recovery of volatiles such as He-3. Work with lunar materials indicates that immature soils are the best candidates for magnetic beneficiation. The magnetic susceptibility at which selected soil components such as anorthite, ilmenite, or metallic iron are separated is not affected by soil maturity, but the recovery of the concentrated components is. Increasing soil maturity lowers recovery. Mature soils contain significant amounts of glass-encased metallic iron. Magnetic susceptibility, which is sensitive to metallic iron content, can be used to measure soil maturity. The relationship between the ratio of magnetic susceptibility and iron oxide and the conventional maturity parameter, I(sub s)/FeO, ferromagnetic resonant intensity divided by iron oxide content is given. The magnetic susceptibilities were determined using apparatus designed for magnetic separation of the lunar soils.

  3. Radiation Transport Properties of Potential In Situ-Developed Regolith-Epoxy Materials for Martian Habitats

    NASA Technical Reports Server (NTRS)

    Miller, Jack; Heilbronn, Lawrence H.; Zeitlin, Cary J.; Wilson, John W.; Singleterry, Robert C., Jr.; Thibeault, Sheila Ann

    2003-01-01

    Mission crews in space outside the Earth s magnetic field will be exposed to high energy heavy charged particles in the galactic cosmic radiation (GCR). These highly ionizing particles will be a source of radiation risk to crews on extended missions to the Moon and Mars, and the biological effects of and countermeasures to the GCR have to be investigated as part of the planning of exploration-class missions. While it is impractical to shield spacecraft and planetary habitats against the entire GCR spectrum, biological and physical studies indicate that relatively modest amounts of shielding are effective at reducing the radiation dose. However, nuclear fragmentation in the shielding materials produces highly penetrating secondary particles, which complicates the problem: in some cases, some shielding is worse than none at all. Therefore the radiation transport properties of potential shielding materials need to be carefully investigated. One intriguing option for a Mars mission is the use of material from the Martian surface, in combination with chemicals carried from Earth and/or fabricated from elements found in the Martian atmosphere, to construct crew habitats. We have measured the transmission properties of epoxy-Martian regolith composites with respect to heavy charged particles characteristic of the GCR ions which bombard the Martian surface. The composites were prepared at NASA Langley Research Center using simulated Martian regolith, in the process also evaluating fabrication methods which could lead to technologies for in situ fabrication on Mars. Initial evaluation of the radiation shielding properties is made using radiation transport models developed at NASA-LaRC, and the results of these calculations are used to select the composites with the most favorable radiation transmission properties. These candidates are then evaluated at particle accelerators which produce beams of heavy charged particles representative in energy and charge of the radiation

  4. Towards soil property retrieval from space: Proof of concept using in situ observations

    NASA Astrophysics Data System (ADS)

    Bandara, Ranmalee; Walker, Jeffrey P.; Rüdiger, Christoph

    2014-05-01

    Soil moisture is a key variable that controls the exchange of water and energy fluxes between the land surface and the atmosphere. However, the temporal evolution of soil moisture is neither easy to measure nor monitor at large scales because of its high spatial variability. This is mainly a result of the local variation in soil properties and vegetation cover. Thus, land surface models are normally used to predict the evolution of soil moisture and yet, despite their importance, these models are based on low-resolution soil property information or typical values. Therefore, the availability of more accurate and detailed soil parameter data than are currently available is vital, if regional or global soil moisture predictions are to be made with the accuracy required for environmental applications. The proposed solution is to estimate the soil hydraulic properties via model calibration to remotely sensed soil moisture observation, with in situ observations used as a proxy in this proof of concept study. Consequently, the feasibility is assessed, and the level of accuracy that can be expected determined, for soil hydraulic property estimation of duplex soil profiles in a semi-arid environment using near-surface soil moisture observations under naturally occurring conditions. The retrieved soil hydraulic parameters were then assessed by their reliability to predict the root zone soil moisture using the Joint UK Land Environment Simulator model. When using parameters that were retrieved using soil moisture observations, the root zone soil moisture was predicted to within an accuracy of 0.04 m3/m3, which is an improvement of ∼0.025 m3/m3 on predictions that used published values or pedo-transfer functions.

  5. Public transit bus ramp slopes measured in situ.

    PubMed

    Bertocci, Gina; Frost, Karen; Smalley, Craig

    2014-05-01

    Abstract Purpose: The slopes of fixed-route bus ramps deployed for wheeled mobility device (WhMD) users during boarding and alighting were assessed. Measured slopes were compared to the proposed Americans with Disabilities Act (ADA) maximum allowable ramp slope. Methods: A ramp-embedded inclinometer measured ramp slope during WhMD user boarding and alighting on a fixed-route transit bus. The extent of bus kneeling was determined for each ramp deployment. In-vehicle video surveillance cameras captured ramp deployment level (street versus sidewalk) and WhMD type. Results: Ramp slopes ranged from -4° to 15.5° with means of 4.3° during boarding (n = 406) and 4.2° during alighting (n = 405). Ramp slope was significantly greater when deployed to street level. During boarding, the proposed ADA maximum allowable ramp slope (9.5°) was exceeded in 66.7% of instances when the ramp was deployed to street level, and in 1.9% of instances when the ramp was deployed to sidewalk level. During alighting, the proposed ADA maximum allowable slope was exceeded in 56.8% of instances when the ramp was deployed to street level and in 1.4% of instances when the ramp was deployed to sidewalk level. Conclusions: Deployment level, built environment and extent of bus kneeling can affect slope of ramps ascended/descended by WhMD users when accessing transit buses. Implications for Rehabilitation Since public transportation services are critical for integration of wheeled mobility device (WhMD) users into the community and society, it is important that they, as well as their therapists, are aware of conditions that may be encountered when accessing transit buses. Knowledge of real world ramp slope conditions that may be encountered when accessing transit buses will allow therapists to better access capabilities of WhMD users in a controlled clinical setting. Real world ramp slope conditions can be recreated in a clinical setting to allow WhMD users to develop and practice necessary

  6. In-situ measurement of the substorm onset instability

    NASA Astrophysics Data System (ADS)

    Murphy, K. R.; Rae, J.; Watt, C.; Forsyth, C.; Mann, I. R.; Yao, Z.; Kalmoni, N.

    2015-12-01

    The substorm is arguably the major mode of variability in near-Earth Space which unpredictably dissipates a considerable and variable amount of energy into the near-Earth magnetosphere and ionosphere. What process or processes determine when this energy is released is uncertain, although it is evident that both near-Earth plasma instability and magnetotail reconnection play a role in this energy release. Much emphasis has recently been placed on the role of magnetic reconnection in substorms, we focus here on observations of the unmistakeable signs of a plasma instability acting at substorm onset. Using data from the THEMIS spacecraft, we show that electromagnetic waves grow in the magnetotail at the expense of the local electron and ion thermal energy. The wave growth in space is the direct counterpart to the wave growth seen at the substorm onset location at the ionosphere, as measured by the CARISMA and THEMIS magnetometers and THEMIS all-sky-imagers. We present evidence that the free energy source for the instability is associated with the electron and ion thermal energy, and not the local electron or ion flow energy.

  7. In situ measurements of ice saturation in young contrails

    NASA Astrophysics Data System (ADS)

    Kaufmann, Stefan; Voigt, Christiane; Jeßberger, Philipp; Jurkat, Tina; Schlager, Hans; Schwarzenboeck, Alfons; Klingebiel, Marcus; Thornberry, Troy

    2014-01-01

    Relative humidity with respect to ice (RHi) is a major factor controlling the evolution of aircraft contrails. High-resolution airborne H2O measurements in and near contrails were made at a rate of 4.2 Hz using the novel water vapor mass spectrometer AIMS-H2O with in-flight calibration during the CONtrail, volcano, and Cirrus ExpeRimenT (CONCERT) 2011. Three 2 min old contrails were sampled near 11 km altitude. Independent of the ambient supersaturation or subsaturation over ice, the mean of the RHi frequency distribution within each contrail is shifted toward ice saturation. This shift can be explained by the high ice surface area densities with corresponding RHi relaxation times on the order of 20 s, which lead to the fast equilibration of H2O between the vapor and ice phase. Understanding the interaction of water vapor with ice particles is essential to investigate the life cycle of contrails and cirrus.

  8. In situ pressure measurements in small gettered volumes

    NASA Astrophysics Data System (ADS)

    Nemanic, Vincenc; Zumer, Marko; Zajec, Bojan

    2002-11-01

    In modern small optoelectronic devices like field emitter displays, miniature cathode ray tubes (CRTs), channel photomultipliers, etc., the vacuum requirements are much more stringent than in conventional electron beam devices. As there should be a pressure in the ultrahigh vacuum region and the volume is only a few cm3, a direct measurement is not feasible and is often estimated on the basis of the expected pumping speed of the getter. The present study was arranged to investigate the pressure in small CRTs (25 cm3) during a period of several months, namely after the conventional pumping and bakeout procedure, immediately after the activation of Ba getters and after the accumulation of some months. All the CRTs were equipped by a spinning rotor gauge ball. Two barium getter sizes were studied: St15/AM/O/9.5 and St15/AM/O/5, both made by SAES. After the evaporation by the prescribed procedure the pressure did not drop, but increased from papprox1 x10-5 mbar up to papprox1 x10-3 mbar, showing that the pumping speed was completely suppressed by forming of a nongetterable gas. When the same experiments were repeated inside identical glass bulbs connected with a valve to a quadrupole mass spectrometer, a formation of methane was observed. The initial rate just after the activation was Qapprox10-8 mbar l s-1, but even after several hours it was still as high as Qapprox10-9 mbar l s-1. By switching-on the cathode heater, methane was pumped by the getter after a precedent cracking procedure. The virtual pumping speed was directly related to the heater power, but independent of the getter area. Therefore, within the cathode warm-up period, methane was "pumped" and did not represent a harmful gaseous contaminant in a small electron beam device with a thermionic cathode. copyright 2002 American Vacuum Society.

  9. Quantitative Imaging and In Situ Concentration Measurements of Quantum Dot Nanomaterials in Variably Saturated Porous Media

    DOE PAGESBeta

    Uyuşur, Burcu; Snee, Preston T.; Li, Chunyan; Darnault, Christophe J. G.

    2016-01-01

    Knowledge of the fate and transport of nanoparticles in the subsurface environment is limited, as techniques to monitor and visualize the transport and distribution of nanoparticles in porous media and measure their in situ concentrations are lacking. To address these issues, we have developed a light transmission and fluorescence method to visualize and measure in situ concentrations of quantum dot (QD) nanoparticles in variably saturated environments. Calibration cells filled with sand as porous medium and various known water saturation levels and QD concentrations were prepared. By measuring the intensity of the light transmitted through porous media exposed to fluorescent lightmore » and by measuring the hue of the light emitted by the QDs under UV light exposure, we obtained simultaneously in situ measurements of water saturation and QD nanoparticle concentrations with high spatial and temporal resolutions. Water saturation was directly proportional to the light intensity. A linear relationship was observed between hue-intensity ratio values and QD concentrations for constant water saturation levels. The advantages and limitations of the light transmission and fluorescence method as well as its implications for visualizing and measuring in situ concentrations of QDs nanoparticles in the subsurface environment are discussed.« less

  10. Upper Mississippi embayment shallow seismic velocities measured in situ

    USGS Publications Warehouse

    Liu, Huaibao P.; Hu, Y.; Dorman, J.; Chang, T.-S.; Chiu, J.-M.

    1997-01-01

    for shallow sediment obtained from reflection, refraction, crosshole and downhole techniques have been obtained for sites at the northern end of the embayment basin. The present borehole data, however, are measured from sites representative of large areas in the Mississippi embayment. Therefore, they fill a gap in information needed for modeling the response of the embayment to destructive seismic shaking.

  11. Relating aerosol absorption due to soot, organic carbon, and dust to emission sources determined from in-situ chemical measurements

    NASA Astrophysics Data System (ADS)

    Cazorla, A.; Bahadur, R.; Suski, K. J.; Cahill, J. F.; Chand, D.; Schmid, B.; Ramanathan, V.; Prather, K. A.

    2013-09-01

    Estimating the aerosol contribution to the global or regional radiative forcing can take advantage of the relationship between the spectral aerosol optical properties and the size and chemical composition of aerosol. Long term global optical measurements from observational networks or satellites can be used in such studies. Using in-situ chemical mixing state measurements can help us to constrain the limitations of such estimates. In this study, the Absorption Ångström Exponent (AAE) and the Scattering Ångström Exponent (SAE) derived from 10 operational AERONET sites in California are combined for deducing chemical speciation based on wavelength dependence of the optical properties. In addition, in-situ optical properties and single particle chemical composition measured during three aircraft field campaigns in California between 2010 and 2011 are combined in order to validate the methodology used for the estimates of aerosol chemistry using spectral optical properties. Results from this study indicate a dominance of mixed types in the classification leading to an underestimation of the primary sources, however secondary sources are better classified. The distinction between carbonaceous aerosols from fossil fuel and biomass burning origins is not clear, since their optical properties are similar. On the other hand, knowledge of the aerosol sources in California from chemical studies help to identify other misclassification such as the dust contribution.

  12. Free-carrier-induced soliton fission unveiled by in situ measurements in nanophotonic waveguides.

    PubMed

    Husko, Chad; Wulf, Matthias; Lefrancois, Simon; Combrié, Sylvain; Lehoucq, Gaëlle; De Rossi, Alfredo; Eggleton, Benjamin J; Kuipers, L

    2016-01-01

    Solitons are localized waves formed by a balance of focusing and defocusing effects. These nonlinear waves exist in diverse forms of matter yet exhibit similar properties including stability, periodic recurrence and particle-like trajectories. One important property is soliton fission, a process by which an energetic higher-order soliton breaks apart due to dispersive or nonlinear perturbations. Here we demonstrate through both experiment and theory that nonlinear photocarrier generation can induce soliton fission. Using near-field measurements, we directly observe the nonlinear spatial and temporal evolution of optical pulses in situ in a nanophotonic semiconductor waveguide. We develop an analytic formalism describing the free-carrier dispersion (FCD) perturbation and show the experiment exceeds the minimum threshold by an order of magnitude. We confirm these observations with a numerical nonlinear Schrödinger equation model. These results provide a fundamental explanation and physical scaling of optical pulse evolution in free-carrier media and could enable improved supercontinuum sources in gas based and integrated semiconductor waveguides. PMID:27079683

  13. Free-carrier-induced soliton fission unveiled by in situ measurements in nanophotonic waveguides

    NASA Astrophysics Data System (ADS)

    Husko, Chad; Wulf, Matthias; Lefrancois, Simon; Combrié, Sylvain; Lehoucq, Gaëlle; de Rossi, Alfredo; Eggleton, Benjamin J.; Kuipers, L.

    2016-04-01

    Solitons are localized waves formed by a balance of focusing and defocusing effects. These nonlinear waves exist in diverse forms of matter yet exhibit similar properties including stability, periodic recurrence and particle-like trajectories. One important property is soliton fission, a process by which an energetic higher-order soliton breaks apart due to dispersive or nonlinear perturbations. Here we demonstrate through both experiment and theory that nonlinear photocarrier generation can induce soliton fission. Using near-field measurements, we directly observe the nonlinear spatial and temporal evolution of optical pulses in situ in a nanophotonic semiconductor waveguide. We develop an analytic formalism describing the free-carrier dispersion (FCD) perturbation and show the experiment exceeds the minimum threshold by an order of magnitude. We confirm these observations with a numerical nonlinear Schrödinger equation model. These results provide a fundamental explanation and physical scaling of optical pulse evolution in free-carrier media and could enable improved supercontinuum sources in gas based and integrated semiconductor waveguides.

  14. Free-carrier-induced soliton fission unveiled by in situ measurements in nanophotonic waveguides

    DOE PAGESBeta

    Husko, Chad; Wulf, Matthias; Lefrancois, Simon; Combrié, Sylvain; Lehoucq, Gaëlle; De Rossi, Alfredo; Eggleton, Benjamin J.; Kuipers, L.

    2016-04-15

    Solitons are localized waves formed by a balance of focusing and defocusing effects. These nonlinear waves exist in diverse forms of matter yet exhibit similar properties including stability, periodic recurrence and particle-like trajectories. One important property is soliton fission, a process by which an energetic higher-order soliton breaks apart due to dispersive or nonlinear perturbations. Here we demonstrate through both experiment and theory that nonlinear photocarrier generation can induce soliton fission. Using near-field measurements, we directly observe the nonlinear spatial and temporal evolution of optical pulses in situ in a nanophotonic semiconductor waveguide. We develop an analytic formalism describing themore » free-carrier dispersion (FCD) perturbation and show the experiment exceeds the minimum threshold by an order of magnitude. We confirm these observations with a numerical nonlinear Schrodinger equation model. Finally, these results provide a fundamental explanation and physical scaling of optical pulse evolution in free-carrier media and could enable improved supercontinuum sources in gas based and integrated semiconductor waveguides.« less

  15. Free-carrier-induced soliton fission unveiled by in situ measurements in nanophotonic waveguides

    PubMed Central

    Husko, Chad; Wulf, Matthias; Lefrancois, Simon; Combrié, Sylvain; Lehoucq, Gaëlle; De Rossi, Alfredo; Eggleton, Benjamin J.; Kuipers, L.

    2016-01-01

    Solitons are localized waves formed by a balance of focusing and defocusing effects. These nonlinear waves exist in diverse forms of matter yet exhibit similar properties including stability, periodic recurrence and particle-like trajectories. One important property is soliton fission, a process by which an energetic higher-order soliton breaks apart due to dispersive or nonlinear perturbations. Here we demonstrate through both experiment and theory that nonlinear photocarrier generation can induce soliton fission. Using near-field measurements, we directly observe the nonlinear spatial and temporal evolution of optical pulses in situ in a nanophotonic semiconductor waveguide. We develop an analytic formalism describing the free-carrier dispersion (FCD) perturbation and show the experiment exceeds the minimum threshold by an order of magnitude. We confirm these observations with a numerical nonlinear Schrödinger equation model. These results provide a fundamental explanation and physical scaling of optical pulse evolution in free-carrier media and could enable improved supercontinuum sources in gas based and integrated semiconductor waveguides. PMID:27079683

  16. Structural and Radiation Shielding Properties of a Martian Habitat Material Synthesized From In-Situ Resources

    NASA Technical Reports Server (NTRS)

    Sen, S.; Caranza, S.; Bhattacharya, M.; Makel, D. B.

    2006-01-01

    The 2 primary requirements of a Martian habitat structure include sufficient structural integrity and effective radiation shielding. In addition, the capability to synthesize such building materials primarily from in-situ resources would significantly reduce the cost associated with transportation of such materials and structures from earth. To demonstrate the feasibility of such an approach we have fabricated samples in the laboratory using simulated in-situ resources, evaluated radiation shielding effectiveness using radiation transport codes and radiation test data, and conducted mechanical properties testing. In this paper we will present experimental results that demonstrate the synthesis of polyethylene from a simulated Martian atmosphere and the fabrication of a composite material using simulated Martian regolith with polyethylene as the binding material. Results from radiation transport calculations and data from laboratory radiation testing using a 500 MeV/nucleon Fe beam will be discussed. Mechanical properties of the proposed composite as a function of composition and processing parameters will also be presented.

  17. A new device for high precision in situ sediment temperature profile measurements at the seafloor

    NASA Astrophysics Data System (ADS)

    Feseker, T.; Wetzel, G.; Heesemann, B.

    2012-04-01

    In situ sediment temperature profile measurements at the seafloor provide valuable information on fluid seepage, hydrate stability, and ambient temperature of samples. In addition, it can be convenient to approximate other parameters such as concentrations of porewater constituents from temperature or temperature gradient using transfer functions if their distribution is controlled by the same processes and direct quantification involves time-consuming sampling and laboratory analyses. We present a new instrument that can be used to obtain precisely positioned sediment temperature profile measurements from the seafloor during ROV dives. Consisting of a 0.4 m-long sensor rod equipped with eight temperature sensors and a standard data logger, the new T-Stick can be operated by an ROV in a fully autonomous mode. The temperature range of the instrument is -5 °C to 35 °C and it can withstand pressures of up to 600 bar. Compared to previously used instruments, the smaller diameter of the new T-Stick reduces the thermal inertia of the lance and results in shorter equilibration times. Virtual measurements generated by a numerical model showed that the T-Stick provides highly accurate temperature profile measurements with a root mean square error of 0.0027 K for a wide range of thermal sediment properties. Modeled temperature gradients are representative of both normal deep sea settings and cold seep environments with elevated temperature gradients of up to three orders of magnitude above normal background values, which are the primary target areas for T-Stick measurements. Deviations from the true in situ temperature profiles are caused by disturbance of the temperature field by the probe itself and may lead to underestimation of gradients and curvature in the profiles. A first field test of the T-Stick was conducted at the Håkon Mosby mud volcano at 1250 m water depth on the Barents Sea slope, where the new instrument provided useful information about the origin and

  18. In situ growth of copper nanocrystals from carbonaceous microspheres with electrochemical glucose sensing properties

    SciTech Connect

    Zhou, Xiaoliang; Yan, Zhengguang Han, Xiaodong

    2014-02-01

    Graphical abstract: In situ growth of copper nanoparticles from hydrothermal copper-containing carbonaceous microspheres was induced by annealing or electron beam irradiation. Obtained micro-nano carbon/copper composite microspheres show electrochemical glucose sensing properties. - Highlights: • We synthesized carbonaceous microspheres containing non-nanoparicle copper species through a hydrothermal route. • By annealing or electron beam irradiation, copper nanoparticles would form from the carbonaceous microspheres in situ. • By controlling the annealing temperature, particle size of copper could be controlled in the range of 50–500 nm. • The annealed carbon/copper hierarchical composite microspheres were used to fabricate an electrochemical glucose sensor. - Abstract: In situ growth of copper nanocrystals from carbon/copper microspheres was observed in a well-controlled annealing or an electron beam irradiation process. Carbonaceous microspheres containing copper species with a smooth appearance were yielded by a hydrothermal synthesis using copper nitrate and ascorbic acid as reactants. When annealing the carbonaceous microspheres under inert atmosphere, copper nanoparticles were formed on carbon microspheres and the copper particle sizes can be increased to a range of 50–500 nm by altering the heating temperature. Similarly, in situ formation of copper nanocrystals from these carbonaceous microspheres was observed on the hydrothermal product carbonaceous microspheres with electron beam irradiation in a vacuum transmission electron microscopy chamber. The carbon/copper composite microspheres obtained through annealing were used to modify a glassy carbon electrode and tested as an electrochemical glucose sensor.

  19. Towards in situ and high frequency estimates of suspended sediment properties

    NASA Astrophysics Data System (ADS)

    Martínez-Carreras, Núria; Schwab, Michael Peter; Klaus, Julian; Hissler, Christophe

    2016-04-01

    Sediment properties, including sediment-associated chemical constituents and sediment physical properties (as colour), can exhibit significant variations within and between storm runoff events. However, the number of samples included in suspended sediment studies is often limited by the time consuming and expensive laboratory procedures for suspended sediment analysis after stream water sampling. This, in turn, restricts high frequency sampling campaigns to a limited number of events and reduces accuracy when aiming to estimate fluxes and loads of sediment-associated chemical constituents. Our contribution addresses the potential for portable ultraviolet-visible (UV-VIS) light spectrometers (220-730 nm) to estimate suspended sediment properties in situ and at high temporal resolution. As far as we know, these instruments have primarily been developed and used to quantify solute concentrations (e.g. DOC and NO3-N), total concentrations of dissolved and particulate forms (e.g. TOC) and turbidity. Here we argue that light absorbance values can be calibrated to estimate solely sediment properties. For our proof-of-concept experiment, we measured light absorbance at 15-min intervals at the Weierbach catchment (NW Luxembourg, 0.46 km2) from December 2013 to January 2015. We then performed a local calibration using suspended sediment loss-on-ignition (LOI) measurements (n=34). We assessed the performance of several regression models that relate light absorbance measurements with the percentage weight LOI. The robust regression method presented the lowest standard error of prediction (0.48{%}) and was selected for calibration (adjusted r2 = 0.76 between observed and predicted values). This study demonstrates that spectrometers can be used to estimate suspended sediment properties at high temporal resolution and for long time spans in a simple, non-destructive and affordable manner. The advantages and disadvantages of the method compared to traditional approaches will be

  20. Stratospheric free chlorine measured by balloon-borne in situ resonance fluorescence

    NASA Technical Reports Server (NTRS)

    Anderson, J. G.; Grassl, H. J.; Shetter, R. E.; Margitan, J. J.

    1980-01-01

    Eight balloon-borne in situ measurements of ClO in the stratosphere are analyzed and are compared with recent model calculations. While the use of in situ stratospheric studies of free radicals to test models by comparing observed and predicted concentration profiles is essential for a prognosis of changes in stratospheric ozone, resulting from future changes in stratospheric ozone, such studies provide only limited insight into the nature of stratospheric photochemistry, because natural variability and the large number of fast reactions which compete in the coupling among the key radicals frustrate a detailed comparison between a mean distribution provided by the models and an instantaneous distribution provided by a single observation.

  1. Radioactivity measurements in the aquatic environment using in-situ and laboratory gamma-ray spectrometry.

    PubMed

    Eleftheriou, G; Tsabaris, C; Androulakaki, E G; Patiris, D L; Kokkoris, M; Kalfas, C A; Vlastou, R

    2013-12-01

    The in-situ underwater gamma-ray spectrometry method is validated by inter-comparison with laboratory method. Deployments of the spectrometer KATERINA on a submarine spring and laboratory measurements of water samples with HPGe detector were performed. Efficiency calibrations, Monte Carlo simulations and the Minimum Detectable Activity (MDA) estimations were realized. MDAs varied from 0.19 to 10.4 (lab) and 0.05 to 0.35 (in-situ) Bq/L, while activity concentrations differed from 7% (for radon progenies) up to 10% (for (40)K), between the two methods. PMID:24103707

  2. Utilizing The Synergy of Airborne Backscatter Lidar and In-Situ Measurements for Evaluating CALIPSO

    NASA Astrophysics Data System (ADS)

    Tsekeri, Alexandra; Amiridis, Vassilis; Marenco, Franco; Marinou, Eleni; Rosenberg, Phil; Solomos, Stavros; Trembath, Jamie; Allan, James; Bacak, Asan; Nenes, Athanasios

    2016-06-01

    Airborne campaigns dedicated to satellite validation are crucial for the effective global aerosol monitoring. CALIPSO is currently the only active remote sensing satellite mission, acquiring the vertical profiles of the aerosol backscatter and extinction coefficients. Here we present a method for CALIPSO evaluation from combining lidar and in-situ airborne measurements. The limitations of the method have to do mainly with the in-situ instrumentation capabilities and the hydration modelling. We also discuss the future implementation of our method in the ICE-D campaign (Cape Verde, August 2015).

  3. Identifying mechanical property parameters of planetary soil using in-situ data obtained from exploration rovers

    NASA Astrophysics Data System (ADS)

    Ding, Liang; Gao, Haibo; Liu, Zhen; Deng, Zongquan; Liu, Guangjun

    2015-12-01

    Identifying the mechanical property parameters of planetary soil based on terramechanics models using in-situ data obtained from autonomous planetary exploration rovers is both an important scientific goal and essential for control strategy optimization and high-fidelity simulations of rovers. However, identifying all the terrain parameters is a challenging task because of the nonlinear and coupling nature of the involved functions. Three parameter identification methods are presented in this paper to serve different purposes based on an improved terramechanics model that takes into account the effects of slip, wheel lugs, etc. Parameter sensitivity and coupling of the equations are analyzed, and the parameters are grouped according to their sensitivity to the normal force, resistance moment and drawbar pull. An iterative identification method using the original integral model is developed first. In order to realize real-time identification, the model is then simplified by linearizing the normal and shearing stresses to derive decoupled closed-form analytical equations. Each equation contains one or two groups of soil parameters, making step-by-step identification of all the unknowns feasible. Experiments were performed using six different types of single-wheels as well as a four-wheeled rover moving on planetary soil simulant. All the unknown model parameters were identified using the measured data and compared with the values obtained by conventional experiments. It is verified that the proposed iterative identification method provides improved accuracy, making it suitable for scientific studies of soil properties, whereas the step-by-step identification methods based on simplified models require less calculation time, making them more suitable for real-time applications. The models have less than 10% margin of error comparing with the measured results when predicting the interaction forces and moments using the corresponding identified parameters.

  4. Molecular recognition in gas sensing: Results from acoustic wave and in-situ FTIR measurements

    SciTech Connect

    Hierlemann, A.; Ricco, A.J.; Bodenhoefer, K.; Goepel, W.

    1998-06-01

    Surface acoustic wave (SAW) measurements were combined with direct, in-situ molecular spectroscopy to understand the interactions of surface-confined sensing films with gas-phase analytes. This was accomplished by collecting Fourier-transform infrared external-reflectance spectra (FTIR-ERS) on operating SAW devices during dosing of their specifically coated surfaces with key analytes.

  5. In-situ measurement of the electrical conductivity of aluminum oxide in HFIR

    SciTech Connect

    Zinkle, S.J.; White, D.P.; Snead, L.L.

    1996-10-01

    A collaborative DOE/Monbusho irradiation experiment has been completed which measured the in-situ electrical resistivity of 12 different grades of aluminum oxide during HFIR neutron irradiation at 450{degrees}C. No evidence for bulk RIED was observed following irradiation to a maximum dose of 3 dpa with an applied dc electric field of 200 V/mm.

  6. In situ measurements of Arctic atmospheric trace constituents from an aircraft

    NASA Technical Reports Server (NTRS)

    Reck, G. M.; Briehl, D.; Nyland, T. W.

    1977-01-01

    In situ measurements of the ambient concentrations of several atmospheric trace constituents were obtained using instruments installed on board the NASA Convair 990 aircraft at altitudes up to 12.5 kilometers over Alaska and the Arctic Ocean. Concentration data on ozone, carbon monoxide, water vapor, and particles larger than 0.5 micrometer in diameter were acquired.

  7. MEASURING VERTICAL PROFILES OF HYDRAULIC CONDUCTIVITY WITH IN SITU DIRECT-PUSH METHODS

    EPA Science Inventory

    U.S. EPA (Environmental Protection Agency) staff developed a field procedure to measure hydraulic conductivity using a direct-push system to obtain vertical profiles of hydraulic conductivity. Vertical profiles were obtained using an in situ field device-composed of a
    Geopr...

  8. In-situ Measurements of Colloid Transport and Retention Using Synchroton X-ray Fluorescence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The physics regarding the retention and mobilization of colloids in saturated and unsaturated conditions remains poorly understood, partially due to the inability to measure colloid concentrations in-situ. In this study, we attached Cd+2 ions to clay colloids, and used synchrotron x-rays to cause th...

  9. IN SITU APPARENT CONDUCTIVITY MEASUREMENTS AND MICROBIAL POPULATION DISTRIBUTION AT A HYDROCARBON CONTAMINATED SITE

    EPA Science Inventory

    We investigated the bulk electrical conductivity and microbial population distribution in sediments at a site contaminated with light non-aqueous phase liquid (LNAPL). The bulk conductivity was measured using in situ vertical resistivity probes, while the most probable number met...

  10. In situ measurement of dissolved chloride in high temperature hydrothermal fluids

    NASA Astrophysics Data System (ADS)

    Larson, B. I.; Olson, E. J.; Lilley, M. D.

    2007-05-01

    The ability to continuously monitor chemical properties of hydrothermal vent effluents for extended periods of time is essential to understanding dynamic processes responsible for the temporally variable nature of mid-ocean ridge hydrothermal systems. Although instruments do exist for some parameters, there has been no sensor capable of measuring the chloride concentration, an indicator of possible phase separation, on a real-time and long-term basis. In this article, we discuss the construction of a novel instrument which measures solution resistance as a proxy for chloride concentration. The sensor consists of four gold electrodes embedded in a cylindrical ZrO 2 ceramic housing. It has been successfully deployed in several high temperature vents at the Main Endeavour Field (MEF) on the Juan de Fuca ridge in the NE Pacific, and calibrated under simulated hydrothermal conditions ranging up to 380 °C and 300 bar. The in situ data clearly demonstrate a tidal influence on the effluent from some high temperature vents possibly relating to a subsurface mixing process involving non-seawater end-members. Non-tidal changes are used to constrain the sequence and type of controls operating on fluids circulating within the subsurface.

  11. In situ real-time measurement of physical characteristics of airborne bacterial particles

    NASA Astrophysics Data System (ADS)

    Jung, Jae Hee; Lee, Jung Eun

    2013-12-01

    Bioaerosols, including aerosolized bacteria, viruses, and fungi, are associated with public health and environmental problems. One promising control method to reduce the harmful effects of bioaerosols is thermal inactivation via a continuous-flow high-temperature short-time (HTST) system. However, variations in bioaerosol physical characteristics - for example, the particle size and shape - during the continuous-flow inactivation process can change the transport properties in the air, which can affect particle deposition in the human respiratory system or the filtration efficiency of ventilation systems. Real-time particle monitoring techniques are a desirable alternative to the time-consuming process of microscopic analysis that is conventionally used in sampling and particle characterization. Here, we report in situ real-time optical scattering measurements of the physical characteristics of airborne bacteria particles following an HTST process in a continuous-flow system. Our results demonstrate that the aerodynamic diameter of bacterial aerosols decreases when exposed to a high-temperature environment, and that the shape of the bacterial cells is significantly altered. These variations in physical characteristics using optical scattering measurements were found to be in agreement with the results of scanning electron microscopy analysis.

  12. Using ultrasound transmission velocity to analyse the mechanical properties of teeth after in vitro, in situ, and in vivo irradiation.

    PubMed

    al-Nawas, B; Grötz, K A; Rose, E; Duschner, H; Kann, P; Wagner, W

    2000-09-01

    Ultrasound transmission velocity (UTV) in isotropic material as a measure for the modulus of elasticity was correlated to mechanical properties. Changes in micromechanical properties of radiated teeth and influence of the oral cavity were to be evaluated nondestructively. UTV was measured in extracted teeth after 36 Gy and 62 Gy of in situ (enorally, with no contact to the oral cavity) and in vitro irradiation. Relative to controls, teeth subjected to 62 Gy in vivo showed higher UTV values for dentine and enamel. Sound teeth irradiated with 60 Gy in situ also showed higher UTV values for enamel, whereas dentine values were not significantly different from those of control. The mechanical properties of teeth irradiated in vitro were affected only after high experimental doses of up to 500 Gy. The difference between in vivo and in vitro mechanical properties may be due to radioxerostomia-induced damages as well as the status of dentine vitality. This supports the concept of direct radiation-induced damage in synergy with radioxerostomia-induced caries.

  13. Summary of in situ epitaxial nucleation and growth measurements. [for semiconducting single crystal PbSe films

    NASA Technical Reports Server (NTRS)

    Poppa, H.; Moorhead, R. D.; Heinemann, K.

    1974-01-01

    In situ nucleation and growth measurements of Ag and Au on single-crystal PbSe thin films were made using a transmission electron microscope. Properties studied were polymorphism, crystalline perfection, and the stoichiometric composition of the initial and the autoepitaxially thickened PbSe substrates. The quantitative nucleation and cluster growth measurements were limited to low-saturation conditions. The epitaxial orientations are discussed, and evidence is presented as to the stage of deposition at which the epitaxial order for Ag is introduced. Strong substrate/overgrowth interaction manifested itself by alloying and interdiffusion.

  14. Adsorption of tannic acid on polyelectrolyte monolayers determined in situ by streaming potential measurements.

    PubMed

    Oćwieja, M; Adamczyk, Z; Morga, M

    2015-01-15

    Physicochemical characteristics of tannic acid (tannin) suspensions comprising its stability for a wide range of ionic strength and pH were thoroughly investigated using UV-vis spectrophotometry, dynamic light scattering and microelectrophoretic measurements. These studies allowed to determine the hydrodynamic diameter of the tannic acid that was 1.63 nm for the pH range 3.5-5.5. For pH above 6.0 the hydrodynamic diameter significantly decreased as a result of the tannin hydrolysis. The electrophoretic mobility measurements confirmed that tannic acid is negatively charged for these values of pH and ionic strength 10(-4)-10(-2) M. Therefore, in order to promote adsorption of tannin molecules on negatively charged mica, the poly(allylamine hydrochloride) (PAH) supporting monolayers were first adsorbed under diffusion transport conditions. The coverage of polyelectrolyte monolayers was regulated by changing bulk concentration of PAH and the adsorption time. The electrokinetic characteristics of bare and PAH-covered mica were determined using the streaming potential measurements. The zeta potential of these PAH monolayers was highly positive, equal to 46 mV for ionic strength of 10(-2) M. The kinetics of tannin adsorption on these PAH supporting monolayers was evaluated by the in situ the streaming potential measurements. The zeta potential of PAH monolayers abruptly decreases with the adsorption of tannin molecules that was quantitatively interpreted in terms of the three-dimensional electrokinetic model. The acid-base characteristics of tannin monolayers were acquired via the streaming potential measurements for a broad range of pH. The obtained results indicate that it is possible to control adsorption of tannin on positively charged surfaces in order to designed new multilayer structures of desirable electrokinetic properties and stability.

  15. In situ radiation measurements at the former Soviet Nuclear Test Site

    SciTech Connect

    Tipton, W.J.

    1996-06-01

    A team from the Remote Sensing Laboratory conducted a series of in situ radiological measurements at the former Soviet Nuclear Test Site near Semipalatinsk, Kazakhstan, during the period of July 21-30, 1994. The survey team measured the terrestrial gamma radiation at selected areas on the site to determine the levels of natural and man-made radiation. The survey was part of a cooperative effort between the United States team and teams of radiation scientists from the National Nuclear Center of the Republic of Kazakhstan and the V.G. Khlopin Radium Institute in St. Petersburg, Russia. In addition to in situ radiation measurements made by the United States and Russian teams, soil samples were collected and analyzed by the Russian and Kazakhstani teams. All teams conducted their measurements at ten locations within the test site. The United States team also made a number of additional measurements to locate and verify the positions of three potential fallout plumes containing plutonium contamination from nonnuclear tests. In addition, the United States team made several measurements in Kurchatov City, the housing area used by personnel and their families who work(ed) at the test sites. Comparisons between the United States and Russian in situ measurements and the soil sample results are presented as well as comparisons with a Soviet aerial survey conducted in 1990-1991. The agreement between the different types of measurements made by all three countries was quite good.

  16. Initial in Situ Measurements of Perennial Meltwater Storage in the Greenland Firn Aquifer

    NASA Technical Reports Server (NTRS)

    Koenig, Lora S.; Miege, Clement; Forster, Richard R.; Brucker, Ludovic

    2014-01-01

    A perennial storage of water in a firn aquifer was discovered in southeast Greenland in 2011. We present the first in situ measurements of the aquifer, including densities and temperatures. Water was present at depths between approx. 12 and 37m and amounted to 18.7 +/- 0.9 kg in the extracted core. The water filled the firn to capacity at approx. 35m. Measurements show the aquifer temperature remained at the melting point, representing a large heat reservoir within the firn. Using model results of liquid water extent and aquifer surface depth from radar measurements, we extend our in situ measurements to the Greenland ice sheet. The estimated water volume is 140 +/- 20 Gt, representing approx. 0.4mm of sea level rise (SLR). It is unknown if the aquifer temporary buffers SLR or contributes to SLR through drainage and/or ice dynamics.

  17. In Situ Measurement Activities at the Nasa Orbital Debris Program Office

    NASA Technical Reports Server (NTRS)

    Liou, J.-C.; Burchell, M.; Corsaro, R.; Drolshagen, G.; Giovane, F.; Pisacane, V.; Stansbery, E.

    2009-01-01

    The NASA Orbital Debris Program Office has been involved in the development of several particle impact instruments since 2003. The main objective of this development is to eventually conduct in situ measurements to better characterize the small (millimeter or smaller) orbital debris and micrometeoroid populations in the near-Earth environment. In addition, the Office also supports similar instrument development to define the micrometeoroid and lunar secondary ejecta environment for future lunar exploration activities. The instruments include impact acoustic sensors, resistive grid sensors, fiber optic displacement sensors, and impact ionization sensors. They rely on different mechanisms and detection principles to identify particle impacts. A system consisting of these different sensors will provide data that are complimentary to each other, and will provide a better description of the physical and dynamical properties (e.g., size, mass, and impact speed) of the particles in the environment. Details of several systems being considered by the Office and their intended mission objectives are summarized in this paper.

  18. Using in situ airborne measurements to evaluate three cloud phase products derived from CALIPSO

    NASA Astrophysics Data System (ADS)

    Cesana, G.; Chepfer, H.; Winker, D.; Getzewich, B.; Cai, X.; Jourdan, O.; Mioche, G.; Okamoto, H.; Hagihara, Y.; Noel, V.; Reverdy, M.

    2016-05-01

    We compare the cloud detection and cloud phase determination of three independent climatologies based on Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) to airborne in situ measurements. Our analysis of the cloud detection shows that the differences between the satellite and in situ measurements mainly arise from three factors. First, averaging CALIPSO Level l data along track before cloud detection increases the estimate of high- and low-level cloud fractions. Second, the vertical averaging of Level 1 data before cloud detection tends to artificially increase the cloud vertical extent. Third, the differences in classification of fully attenuated pixels among the CALIPSO climatologies lead to differences in the low-level Arctic cloud fractions. In another section, we compare the cloudy pixels detected by colocated in situ and satellite observations to study the cloud phase determination. At midlatitudes, retrievals of homogeneous high ice clouds by CALIPSO data sets are very robust (more than 94.6% of agreement with in situ). In the Arctic, where the cloud phase vertical variability is larger within a 480 m pixel, all climatologies show disagreements with the in situ measurements and CALIPSO-General Circulation Models-Oriented Cloud Product (GOCCP) report significant undefined-phase clouds, which likely correspond to mixed-phase clouds. In all CALIPSO products, the phase determination is dominated by the cloud top phase. Finally, we use global statistics to demonstrate that main differences between the CALIPSO cloud phase products stem from the cloud detection (horizontal averaging, fully attenuated pixels) rather than the cloud phase determination procedures.

  19. Measuring Level Alignment at the Metal–Molecule Interface by In Situ Electrochemical 13C NMR

    SciTech Connect

    Li, Ying; Zelakiewicz, Brian S.; Allison, Thomas C.; Tong, Yu ye J.

    2015-03-16

    A new technique to measure energy-level alignment at a metal–molecule interface between the Fermi level of the metal and the frontier orbitals of the molecule is proposed and experimentally demonstrated. The method, which combines the electrochemistry of organo-ligand-stabilized Au nanoparticles with 13C NMR spectroscopy (i.e. in situ electrochemical NMR), enables measuring both occupied and unoccupied states.

  20. In situ measurements of flocculated suspended matter with a video multi sensor system

    NASA Astrophysics Data System (ADS)

    Pfeiffer, A.

    1996-09-01

    During the intercalibration experiment WIMS in the Elbe estuary near Brunsbüttel a new configured Video Multi Sensor System was used to measure floc size, shape and concentration in correlation to tide signals such as current velocity and salinity. The results indicate the problems caused by time-and depth-dependent interference between the parameters. In situ measurements from a floating ship have been conducted, because special efforts are necessary to avoid any destructive influence on the fragile flocs.

  1. Radon in soil gas--exhalation tests and in situ measurements.

    PubMed

    Lindmark, A; Rosen, B

    1985-10-01

    Radon in soil can move into buildings resulting in high radon daughter concentrations. The foundation of a dwelling should be adapted to the radon "risk" which is determined by the radon concentration and the air permeability of the soil. Different measuring procedures are discussed in this paper, both in situ measurements of radon content and laboratory tests on radon exhalation from different types of soils at different water contents. PMID:4081740

  2. In situ recording of particle network formation in liquids by ion conductivity measurements.

    PubMed

    Pfaffenhuber, Christian; Sörgel, Seniz; Weichert, Katja; Bele, Marjan; Mundinger, Tabea; Göbel, Marcus; Maier, Joachim

    2011-09-21

    The formation of fractal silica networks from a colloidal initial state was followed in situ by ion conductivity measurements. The underlying effect is a high interfacial lithium ion conductivity arising when silica particles are brought into contact with Li salt-containing liquid electrolytes. The experimental results were modeled using Monte Carlo simulations and tested using confocal fluorescence laser microscopy and ζ-potential measurements.

  3. Digital Holography for in Situ Real-Time Measurement of Plasma-Facing-Component Erosion

    SciTech Connect

    ThomasJr., C. E.; Granstedt, E. M.; Biewer, Theodore M; Baylor, Larry R; Combs, Stephen Kirk; Meitner, Steven J; Hillis, Donald Lee; Majeski, R.; Kaita, R.

    2014-01-01

    In situ, real time measurement of net plasma-facing-component (PFC) erosion/deposition in a real plasma device is challenging due to the need for good spatial and temporal resolution, sufficient sensitivity, and immunity to fringe-jump errors. Design of a high-sensitivity, potentially high-speed, dual-wavelength CO2 laser digital holography system (nominally immune to fringe jumps) for PFC erosion measurement is discussed.

  4. Metal matrix composite micromechanics: In-situ behavior influence on composite properties

    NASA Technical Reports Server (NTRS)

    Murthy, P. L. N.; Hopkins, D. A.; Chamis, C. C.

    1989-01-01

    Recent efforts in computational mechanics methods for simulating the nonlinear behavior of metal matrix composites have culminated in the implementation of the Metal Matrix Composite Analyzer (METCAN) computer code. In METCAN material nonlinearity is treated at the constituent (fiber, matrix, and interphase) level where the current material model describes a time-temperature-stress dependency of the constituent properties in a material behavior space. The composite properties are synthesized from the constituent instantaneous properties by virtue of composite micromechanics and macromechanics models. The behavior of metal matrix composites depends on fabrication process variables, in situ fiber and matrix properties, bonding between the fiber and matrix, and/or the properties of an interphase between the fiber and matrix. Specifically, the influence of in situ matrix strength and the interphase degradation on the unidirectional composite stress-strain behavior is examined. These types of studies provide insight into micromechanical behavior that may be helpful in resolving discrepancies between experimentally observed composite behavior and predicted response.

  5. Utilizing in situ Directional Hyperpectral Measurements to Validate Bio-Indicator Simulations for a Corn Crop Canaopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two radiative transfer canopy models, SAIL and the Markov-Chain Canopy Reflectance Model (MRCM), were coupled with in situ leaf optical properties to simulate canopy-level spectral band ratio vegetation indices with the focus on the Photochemical Reflectance Index (PRI) in a cornfield. In situ hyper...

  6. Observing cirrus halos to constrain in-situ measurements of ice crystal size

    NASA Astrophysics Data System (ADS)

    Garrett, T. J.; Kimball, M. B.; Mace, G. G.; Baumgardner, D. G.

    2007-01-01

    In this study, characteristic optical sizes of ice crystals in synoptic cirrus are determined using airborne measurements of ice crystal size distributions, optical extinction and water content. The measurements are compared with coincident visual observations of ice cloud optical phenomena, in particular the 22° and 46° halos. In general, the scattering profiles derived from the in-situ cloud probe measurements are consistent with the observed halo characteristics. It is argued that this implies that the measured ice crystals were small, probably with characteristic optical radii between 10 and 20 μm. There is a current contention that in-situ measurements of high concentrations of small ice crystals reflect artifacts from the shattering of large ice crystals on instrument inlets. Significant shattering cannot be entirely excluded using this approximate technique, but it is not indicated. On the basis of the in-situ measurements, a parameterization is provided that relates the optical effective radius of ice crystals to the temperature in mid-latitude synoptic cirrus.

  7. In-situ Balloon Measurements of Small Ice Particles in High-Latitude Cirrus

    NASA Astrophysics Data System (ADS)

    Kuhn, T.; Heymsfield, A.

    2015-12-01

    Thin cirrus clouds at high latitudes are often composed of small ice particles not larger than 100 μm. Cirrus clouds reflect incoming solar radiation, creating a cooling effect. At the same time these clouds absorb the infrared radiation from Earth, creating a greenhouse effect. The net effect, crucial for radiative transfer, depends on the cirrus microphysical properties, such as particle size distributions (PSD) and particle shapes. Knowledge of these cloud properties is also needed for calibrating/validating passive and active remote sensors. We report on a series of balloon-borne in-situ measurements that is carried out at a high-latitude location, Kiruna in northern Sweden (68N 21E). The measurements target upper tropospheric, cold cirrus clouds. The measurements are ongoing, and the method and first results are presented here. Ice particles in these clouds are predominantly very small, with a median size of measured particles of around 50 μm. Ice particles at these sizes are inherently difficult to measure with aircraft-mounted probes due to issues with resolution, sizing, and size-dependent sampling volume. These probes also suffer from problems with shattering of larger ice particles at the typically high aircraft speeds. The method used here avoids these issues. Furthermore, with a balloon-borne instrument data are collected as vertical profiles, more useful for calibrating or evaluating remote sensing measurements than data collected along horizontal traverses. Particles are collected on an oil-coated film at a sampling speed given directly by the ascending rate of the balloon, 4 m s-1. The collecting film is advanced uniformly inside the instrument so that an always un-used section of the film is exposed to ice particles, which are measured by imaging shortly after sampling. The high optical resolution of about 4 μm together with a pixel resolution of 1.65 μm allows particle detection at sizes of 10 μm and larger. For particles that are 20 μm (12

  8. Comparison of MTI satellite-derived surface water temperatures and in-situ measurements

    NASA Astrophysics Data System (ADS)

    Kurzeja, Robert J.; Pendergast, Malcolm M.; Villa-Aleman, Eliel; Garrett, Alfred J.

    2002-01-01

    Temperatures of the water surface of a cold, mid-latitude lake and the tropical Pacific Ocean were determined from MTI images and from in situ concurrent measurements. In situ measurements were obtained at the time of the MTI image with a floating, anchored platform, which measured the surface and bulk water temperatures and relevant meteorological variables, and also from a boat moving across the target area. Atmospheric profiles were obtained from concurrent radiosonde soundings. Radiances at the satellite were calculated with the Modtran radiative transfer model. The MTI infrared radiances were within 1% of the calculated values at the Pacific Ocean site but were 1-2% different over the mid-latitude lake.

  9. Combining Space-Based and In-Situ Measurements to Track Flooding in Thailand

    NASA Technical Reports Server (NTRS)

    Chien, Steve; Doubleday, Joshua; Mclaren, David; Tran, Daniel; Tanpipat, Veerachai; Chitradon, Royal; Boonya-aaroonnet, Surajate; Thanapakpawin, Porranee; Khunboa, Chatchai; Leelapatra, Watis; Plermkamon, Vichian; Raghavendra, Cauligi; Mandl, Daniel

    2011-01-01

    We describe efforts to integrate in-situ sensing, space-borne sensing, hydrological modeling, active control of sensing, and automatic data product generation to enhance monitoring and management of flooding. In our approach, broad coverage sensors and missions such as MODIS, TRMM, and weather satellite information and in-situ weather and river gauging information are all inputs to track flooding via river basin and sub-basin hydrological models. While these inputs can provide significant information as to the major flooding, targetable space measurements can provide better spatial resolution measurements of flooding extent. In order to leverage such assets we automatically task observations in response to automated analysis indications of major flooding. These new measurements are automatically processed and assimilated with the other flooding data. We describe our ongoing efforts to deploy this system to track major flooding events in Thailand.

  10. In Situ Field Measurement of Leaf Water Potential Using Thermocouple Psychrometers 1

    PubMed Central

    Savage, Michael J.; Wiebe, Herman H.; Cass, Alfred

    1983-01-01

    Thermocouple psychrometers are the only instruments which can measure the in situ water potential of intact leaves, and which can possibly be used to monitor leaf water potential. Unfortunately, their usefulness is limited by a number of difficulties, among them fluctuating temperatures and temperature gradients within the psychrometer, sealing of the psychrometer chamber to the leaf, shading of the leaf by the psychrometer, and resistance to water vapor diffusion by the cuticle when the stomates are closed. Using Citrus jambhiri, we have tested several psychrometer design and operational modifications and showed that in situ psychrometric measurements compared favorably with simultaneous Scholander pressure chamber measurements on neighboring leaves when the latter were corrected for the osmotic potential. PMID:16663267

  11. Comparison of MTI Satellite-Derived Surface Water Temperatures and In-Situ Measurements

    SciTech Connect

    Kurzeja, R.

    2001-07-26

    Temperatures of the water surface of a cold, mid-latitude lake and the tropical Pacific Ocean were determined from MTI images and from in situ concurrent measurements. In situ measurements were obtained at the time of the MTI image with a floating, anchored platform, which measured the surface and bulk water temperatures and relevant meteorological variables, and also from a boat moving across the target area. Atmospheric profiles were obtained from concurrent radiosonde soundings. Radiances at the satellite were calculated with the Modtran radiative transfer model. The MTI infrared radiances were within 1 percent of the calculated values at the Pacific Ocean site but were 1-2 percent different over the mid-latitude lake.

  12. In situ measurements of scattering from contaminated optics in the Vacuum Ultraviolet

    NASA Technical Reports Server (NTRS)

    Herren, Kenneth A.; Linton, Roger C.; Whitaker, Ann F.

    1990-01-01

    NASA's In Situ Contamination Effects Facility has been used to measure the time dependence of the angular reflectance from molecularly contaminated optical surfaces in the vacuum ultraviolet. The light scattering measurements are accomplished in situ on optical surfaces in real time during deposition of molecular contaminants. The measurements are taken using noncoherent VUV sources with the predominant wavelengths being the krypton resonance lines at 1236 and 1600 angstroms. Detection of the scattered light is accomplished using a set of three solar blind VUV photomultipliers. An in-plane VUV BRDF (bidirectional reflectance distribution function) experiment is described and details of the on-going program to characterize optical materials exposed to the space environment is reported.

  13. Fibre Bragg grating sensors for in-situ measurement of resin pressure in curing composites

    NASA Astrophysics Data System (ADS)

    Ganapathi, A. S.; Maheshwari, Muneesh; Joshi, Sunil C.; Chen, Zhong; Asundi, Anand; Tjin, Swee Chuan

    2015-03-01

    A fibre optic sensor was developed for in-situ pressure measurement based on the principle of differential pressure in liquids. This sensor system is very simple and consists of fibre Bragg grating (FBG) done on a fibre with core diameter of 9 μm. A calibration study was carried out with a water column and the pressure sensitivity was found to be 1.636 × 10-2MPa-1. The results show that response of FBG to the rise of water level is linear and agrees well with the theoretical results. The reliability of the sensors is confirmed by repeating the measurements for three times. The sensor is useful in applications that involve in-situ resin pressure measurement in manufacturing of laminated composite materials.

  14. Thermal transport in CO2 laser irradiated fused silica: in situ measurements and analysis

    SciTech Connect

    Yang, S T; Matthews, M J; Elhadj, S; Draggoo, V G; Bisson, S E

    2009-07-07

    In situ spatial and temporal temperature measurements of pristine fused silica surfaces heated with a 10.6 {micro}m CO{sub 2} laser were obtained using an infrared radiation thermometer based on a Mercury Cadmium Telluride (MCT) camera. Laser spot sizes ranged from 250 {micro}m to 1000 {micro}m diameter with peak axial irradiance levels of 0.13 to 16 kW/cm{sup 2}. For temperatures below 2800K, the measured steady-state surface temperature is observed to rise linearly with both increasing beam size and incident laser irradiance. The effective thermal conductivity estimated over this range was approximately 2W/mK, in good agreement with classical calculations based on phonon heat capacities. Similarly, time-dependent temperature measurements up to 2000K yielded thermal diffusivity values which were close to reported values of 7 x 10{sup -7} m{sup 2}/s. Above {approx}2800K, the fused silica surface temperature asymptotically approaches 3100K as laser power is further increased, consistent with the onset of evaporative heat losses near the silica boiling point. These results show that in the laser heating regime studied here, the T{sup 3} temperature dependent thermal conductivity due to radiation transport can be neglected, but at temperatures above 2800K heat transport due to evaporation must be considered. The thermal transport in fused silica up to 2800K, over a range of conditions, can then be adequately described by a linear diffusive heat equation assuming constant thermal properties.

  15. Mechanical Properties of In-Situ FeAl-TiB2 Intermetallic Matrix Composites

    NASA Astrophysics Data System (ADS)

    Kim, Jonghoon; Park, Bonggyu; Park, Yongho; Park, Ikmin; Lee, Heesoo

    Intermetallic matrix composites reinforced with ceramic particles have received a great deal of attention. Iron aluminide is known to be a good material for the matrix in such composites. Two processes were used to fabricate FeAl-TiB2 intermetallic matrix composites. One was liquid melt in-situ mixing, and the other was arc melting and suction casting processes. FeAl-TiB2 IMCs obtained by two different methods were investigated to elucidate the influence of TiB2 content. In both methods, the grain size in the FeAl alloy decreased with the presence of titanium diboride. The grain size of in-situ FeAl-TiB2 IMCs became smaller than that of arc FeAl-TiB2 IMCs. Significant increase in fracture stress and hardness was achieved in the composites. The in-situ process gives clean, contamination-free matrix/reinforcement interface which maintained good bonding causing high load bearing capability. This contributed to the increase in the mechanical properties of composites.

  16. Radiation Transport Properties of Potential In Situ-Developed Regolith-Epoxy Materials for Martian Habitats

    NASA Technical Reports Server (NTRS)

    Miller, J.; Heilbronn, L.; Singleterry, R. C., Jr.; Thibeault, S. A.; Wilson, J. W.; Zeitlin, C. J.

    2001-01-01

    We will evaluate the radiation transport properties of epoxy-martian regolith composites. Such composites, which would use both in situ materials and chemicals fabricated from elements found in the martian atmosphere, are candidates for use in habitats on Mars. The principal objective is to evaluate the transmission properties of these materials with respect to the protons and heavy charged particles in the galactic cosmic rays which bombard the martian surface. The secondary objective is to evaluate fabrication methods which could lead to technologies for in situ fabrication. The composites will be prepared by NASA Langley Research Center using simulated martian regolith. Initial evaluation of the radiation shielding properties will be made using transport models developed at NASA-LaRC and the results of these calculations will be used to select the composites with the most favorable radiation transmission properties. These candidates will then be empirically evaluated at particle accelerators which produce beams of protons and heavy charged particles comparable in energy to the radiation at the surface of Mars.

  17. Integrated Airborne and In-Situ Measurements over Land-Fast Ice near Barrow, AK.

    NASA Astrophysics Data System (ADS)

    Brozena, J. M.; Gardner, J. M.; Liang, R.; Ball, D.; Richter-Menge, J.; Claffey, K. J.; Abelev, A.; Hebert, D. A.; Jones, K.

    2014-12-01

    During March of 2014, the Naval Research Laboratory and the Cold Regions Research and Engineering Laboratory collected an integrated set of airborne and in-situ measurements over two areas of floating, but land-fast ice near the coast of Barrow, AK. The near-shore site was just north of Point Barrow, and the "offshore" site was ~ 20 km east of Point Barrow. The in-situ data provided ground-truth for airborne measurements from a scanning LiDAR (Riegl Q 560i), digital photogrammetry (Applanix DSS-439) and a snow radar procured from the Center for Remote Sensing of Ice Sheets of the University of Kansas. The objective of the survey was to aid our understanding of the use of the airborne data to calibrate/validate Cryosat-2 data. Sampling size or "footprint" plays a critical role in the attempt to compare in-situ measurements with airborne (or satellite) measurements. Thus the in-situ data were arranged to minimize aliasing. Ground measurements were collected along transects at both sites consisting of a 2 km long profile of snow depth and ice thickness measurements with periodic boreholes. A 60 m x 400 m swath of snow depth measurements was centered on this profile. Airborne data were collected on five overflights of the two transect areas. The LiDAR measured total freeboard (ice + snow) referenced to leads in the ice, and produced swaths 200-300 m wide. The radar measured snow thickness. The freeboard and snow thickness measurements are used to estimate ice thickness via isostasy and density estimates. The central swath of in situ snow depth data allows examination of the effects of cross-track variations considering the relatively large footprint of the snow radar. Assuming a smooth, flat surface the radar range resolution in air is < 4 cm, but the along-track sampling distance is ~ 3 m after unfocussed SAR processing. The width of the footprint varies from ~ 9 m up to about 40 m (beam-limited) for uneven surfaces. However, the radar could not resolve snow thickness

  18. Study of nitrogen doping of graphene via in-situ transport measurements

    NASA Astrophysics Data System (ADS)

    Zhao, Rong; Afaneh, Tareq; Dharmasena, Ruchira; Jasinski, Jacek; Sumanasekera, Gamini; Henner, Victor

    2016-06-01

    Here we report in-situ monitoring of electrical transport properties of graphene subjected to sequential and controlled nitrogen plasma doping. The nitrogen is presumed to be incorporated in to the carbon lattice of graphene by making covalent bonding as observed by the swinging of the sign of the thermopower from (initial) positive to (eventual) negative. Electrical transport properties for nitrogen-doped graphene are believed to be governed by the enhanced scattering due to nitrogen dopants and presence of localized states in the conduction band induced by doping. Our results are well supported by Raman and XPS results.

  19. Predicting Fracture Toughness of TRIP 800 using Phase Properties Characterized by In-Situ High Energy X-Ray Diffraction

    SciTech Connect

    Soulami, Ayoub; Choi, Kyoo Sil; Liu, Wenning N.; Sun, Xin; Khaleel, Mohammad A.; Ren, Yang; Wang, Yan-Dong

    2010-05-01

    TRansformation Induced Plasticity (TRIP) steel is a typical representative of 1st generation advanced high strength steel (AHSS) which exhibits a combination of high strength and excellent ductility due to its multiphase microstructure. In this paper, we study the crack propagation behavior and fracture resistance of a TRIP 800 steel using a microstructure-based finite element method with the various phase properties characterized by in-situ high energy Xray diffraction (HEXRD) technique. Uniaxial tensile tests on the notched TRIP 800 sheet specimens were also conducted, and the experimentally measured tensile properties and R-curves (Resistance curves) were used to calibrate the modeling parameters and to validate the overall modeling results. The comparison between the simulated and experimentally measured results suggests that the micromechanics based modeling procedure can well capture the overall complex crack propagation behaviors and the fracture resistance of TRIP steels. The methodology adopted here may be used to estimate the fracture resistance of various multiphase materials.

  20. Fuel retention measurements in Alcator C-Mod using accelerator-based in situ materials surveillance

    NASA Astrophysics Data System (ADS)

    Hartwig, Zachary S.; Barnard, Harold S.; Sorbom, Brandon N.; Lanza, Richard C.; Lipschultz, Bruce; Stahle, Peter W.; Whyte, Dennis G.

    2015-08-01

    This paper presents the first in situ time- and space-resolved measurements of deuterium (D) fuel retention in plasma-facing component (PFC) surfaces using Accelerator-based In-situ Materials Surveillance (AIMS) on the Alcator C-Mod tokamak. AIMS is a novel in situ materials diagnostic technique based on the spectroscopic analysis of nuclear reaction products induced in PFC surfaces using an ∼MeV beam of deuterons from a compact linear accelerator in between plasma shots. AIMS measurements of D retention on inner wall PFCs were acquired during diverted and limited plasma operations and during wall conditioning experiments. Intershot measurements demonstrate the local erosion and codeposition of boron films on PFC surfaces with a constant D / B ratio. This is consistent with previous results suggesting that D codeposition with boron is insufficient to account for the net retention observed in Alcator C-Mod. Changes in deuterium concentration during boronization, electron cyclotron and glow cleanings were also measured.

  1. Micro weather stations for in situ measurements in the Martian planetary boundary layer

    NASA Technical Reports Server (NTRS)

    Crisp, D.; Kaiser, W. J.; Kenny, T. W.; Vanzandt, T. R.; Tillman, J. E.

    1992-01-01

    Viking Lander meteorology measurements show that the Martian planetary boundary layer (PBL) has large diurnal and seasonal variations in pressure, wind velocity, relative humidity, and airborne dust loading. An even larger range of conditions was inferred from remote sensing observations acquired by the Mariner 9 and Viking orbiters. Numerical models indicate that these changes may be accompanied by dramatic vertical and horizontal wind shears (100 m/s/km) and rapid changes in the static stability. In-situ measurements from a relatively small number surface stations could yield global constraints on the Martian climate and atmospheric general circulation by providing ground truth for remote sensing instruments on orbiters. A more complete understanding of the meteorology of the PBL is an essential precursor to manned missions to Mars because this will be their working environment. In-situ measurements are needed for these studies because the spatial and temporal scales that characterize the important meteorological processes near the surface cannot be resolved from orbit. The Mars Environmental Survey (MESUR) Program will provide the first opportunity to deploy a network of surface weather stations for a comprehensive investigation of the Martian PBL. The feasibility and utility of a network of micro-weather stations for making in-situ meteorological measurements in the Martian PBL are assessed.

  2. In situ measurement of leaf chlorophyll concentration: analysis of the optical/absolute relationship.

    PubMed

    Parry, Christopher; Blonquist, J Mark; Bugbee, Bruce

    2014-11-01

    In situ optical meters are widely used to estimate leaf chlorophyll concentration, but non-uniform chlorophyll distribution causes optical measurements to vary widely among species for the same chlorophyll concentration. Over 30 studies have sought to quantify the in situ/in vitro (optical/absolute) relationship, but neither chlorophyll extraction nor measurement techniques for in vitro analysis have been consistent among studies. Here we: (1) review standard procedures for measurement of chlorophyll; (2) estimate the error associated with non-standard procedures; and (3) implement the most accurate methods to provide equations for conversion of optical to absolute chlorophyll for 22 species grown in multiple environments. Tests of five Minolta (model SPAD-502) and 25 Opti-Sciences (model CCM-200) meters, manufactured from 1992 to 2013, indicate that differences among replicate models are less than 5%. We thus developed equations for converting between units from these meter types. There was no significant effect of environment on the optical/absolute chlorophyll relationship. We derive the theoretical relationship between optical transmission ratios and absolute chlorophyll concentration and show how non-uniform distribution among species causes a variable, non-linear response. These results link in situ optical measurements with in vitro chlorophyll concentration and provide insight to strategies for radiation capture among diverse species.

  3. Recent Advances in the Tempest UAS for In-Situ Measurements in Highly-Dynamic Environments

    NASA Astrophysics Data System (ADS)

    Argrow, B. M.; Frew, E.; Houston, A. L.; Weiss, C.

    2014-12-01

    The spring 2010 deployment of the Tempest UAS during the VORTEX2 field campaign verified that a small UAS, supported by a customized mobile communications, command, and control (C3) architecture, could simultaneously satisfy Federal Aviation Administration (FAA) airspace requirements, and make in-situ thermodynamic measurements in supercell thunderstorms. A multi-hole airdata probe was recently integrated into the Tempest UAS airframe and verification flights were made in spring 2013 to collect in-situ wind measurements behind gust fronts produced by supercell thunderstorms in northeast Colorado. Using instantaneous aircraft attitude estimates from the autopilot, the in-situ measurements were converted to inertial wind estimates, and estimates of uncertainty in the wind measurements was examined. To date, the limited deployments of the Tempest UAS have primarily focused on addressing the engineering and regulatory requirements to conduct supercell research, and the Tempest UAS team of engineers and meteorologists is preparing for deployments with the focus on collecting targeted data for meteorological exploration and hypothesis testing. We describe the recent expansion of the operations area and altitude ceiling of the Tempest UAS, engineering issues for accurate inertial wind estimates, new concepts of operation that include the simultaneous deployment of multiple aircraft with mobile ground stations, and a brief description of our current effort to develop a capability for the Tempest UAS to perform autonomous path planning to maximize energy harvesting from the local wind field for increased endurance.

  4. Intercomparison of MODIS Albedo Retrievals and In Situ Measurements Across the Global FLUXNET Network

    NASA Technical Reports Server (NTRS)

    Cescatti, Alessandro; Marcolla, Barbara; Vannan, Suresh K. Santhana; Pan, Jerry Yun; Roman, Miguel O.; Yang, Xiaoyuan; Ciais, Philippe; Cook, Robert B.; Law, Beverly E.; Matteucci, Girogio; Migliavacca, Mirco; Moors, Eddy; Richardson, Andrew D.; Seufert, Guenther; Schaaf, Crystal B.

    2012-01-01

    Surface albedo is a key parameter in the Earth's energy balance since it affects the amount of solar radiation directly absorbed at the planet surface. Its variability in time and space can be globally retrieved through the use of remote sensing products. To evaluate and improve the quality of satellite retrievals, careful intercomparisons with in situ measurements of surface albedo are crucial. For this purpose we compared MODIS albedo retrievals with surface measurements taken at 53 FLUXNET sites that met strict conditions of land cover homogeneity. A good agreement between mean yearly values of satellite retrievals and in situ measurements was found (R(exp 2)= 0.82). The mismatch is correlated to the spatial heterogeneity of surface albedo, stressing the relevance of land cover homogeneity when comparing point to pixel data. When the seasonal patterns of MODIS albedo is considered for different plant functional types, the match with surface observation is extremely good at all forest sites. On the contrary, in non-forest sites satellite retrievals underestimate in situ measurements across the seasonal cycle. The mismatch observed at grasslands and croplands sites is likely due to the extreme fragmentation of these landscapes, as confirmed by geostatistical attributes derived from high resolution scenes.

  5. In situ azimuthal rotation device for linear dichroism measurements in scanning transmission x-ray microscopy

    NASA Astrophysics Data System (ADS)

    Hernández-Cruz, D.; Hitchcock, A. P.; Tyliszczak, T.; Rousseau, M.-E.; Pézolet, M.

    2007-03-01

    A novel miniature rotation device used in conjunction with a scanning transmission x-ray microscope is described. It provides convenient in situ sample rotation to enable measurements of linear dichroism at high spatial resolution. The design, fabrication, and mechanical characterization are presented. This device has been used to generate quantitative maps of the spatial distribution of the orientation of proteins in several different spider and silkworm silks. Specifically, quantitative maps of the dichroic signal at the C 1s→π*amide transition in longitudinal sections of the silk fibers give information about the spatial orientation, degree of alignment, and spatial distribution of protein peptide bonds. A new approach for analyzing the dichroic signal to extract orientation distributions, in addition to magnitudes of aligned components, is presented and illustrated with results from Nephila clavipes dragline spider silk measured using the in situ rotation device.

  6. Nitride-MBE system for in situ synchrotron X-ray measurements

    NASA Astrophysics Data System (ADS)

    Sasaki, Takuo; Ishikawa, Fumitaro; Yamaguchi, Tomohiro; Takahasi, Masamitu

    2016-05-01

    A molecular beam epitaxy (MBE) chamber dedicated to nitride growth was developed at the synchrotron radiation facility SPring-8. This chamber has two beryllium windows for incident and outgoing X-rays, and is directly connected to an X-ray diffractometer, enabling in situ synchrotron X-ray measurements during the nitride growth. Experimental results on initial growth dynamics in GaN/SiC, AlN/SiC, and InN/GaN heteroepitaxy were presented. We achieved high-speed and high-sensitivity reciprocal space mapping with a thickness resolution of atomic-layer scale. This in situ measurement using the high-brilliance synchrotron light source will be useful for evaluating structural variations in the initial growth stage of nitride semiconductors.

  7. Spatially resolved, in situ potential measurements through porous electrodes as applied to fuel cells.

    PubMed

    Hess, Katherine C; Epting, William K; Litster, Shawn

    2011-12-15

    We report the development and use of a microstructured electrode scaffold (MES) to make spatially resolved, in situ, electrolyte potential measurements through the thickness of a polymer electrolyte fuel cell (PEFC) electrode. This new approach uses a microfabricated apparatus to analyze the coupled transport and electrochemical phenomena in porous electrodes at the microscale. In this study, the MES allows the fuel cell to run under near-standard operating conditions, while providing electrolyte potential measurements at discrete distances through the electrode's thickness. Here we use spatial distributions of electrolyte potential to evaluate the effects of Ohmic and mass transport resistances on the through-plane reaction distribution for various operating conditions. Additionally, we use the potential distributions to estimate the ionic conductivity of the electrode. Our results indicate the in situ conductivity is higher than typically estimated for PEFC electrodes based on bulk polymer electrolyte membrane (PEM) conductivity.

  8. Chemical isolation of quartz for measurement of in-situ-produced cosmogenic nuclides

    NASA Technical Reports Server (NTRS)

    Kohl, C. P.; Nishiizumi, K.

    1992-01-01

    An isolation method relying totally on chemical steps was developed to separate large quantities (10-200 g) of clean mono-minerallic quartz samples from a variety of terrestrial rocks and soils for the purpose of measuring Be-10 (t1/2 = 1.5 Myr) and Al-26 (t1/2 = 0.705 Myr) produced by cosmic rays in situ in the quartz phase. The procedure consists of grinding the sample, heating it in HCl, and treating it with a series of leaches using a dilute HF/HNO3 mixture in a heated ultrasonic tank. The purified quartz was also used for the measurements of in situ cosmic-ray-produced Ne-21 and C-14 (t1/2 = 5730 yr). The method is applicable to any problem requiring purified quartz on a large scale.

  9. Apparatus for in-situ calibration of instruments that measure fluid depth

    DOEpatents

    Campbell, M.D.

    1994-01-11

    The present invention provides a method and apparatus for in-situ calibration of distance measuring equipment. The method comprises obtaining a first distance measurement in a first location, then obtaining at least one other distance measurement in at least one other location of a precisely known distance from the first location, and calculating a calibration constant. The method is applied specifically to calculating a calibration constant for obtaining fluid level and embodied in an apparatus using a pressure transducer and a spacer of precisely known length. The calibration constant is used to calculate the depth of a fluid from subsequent single pressure measurements at any submerged position. 8 figures.

  10. Apparatus for in-situ calibration of instruments that measure fluid depth

    DOEpatents

    Campbell, Melvin D.

    1994-01-01

    The present invention provides a method and apparatus for in-situ calibration of distance measuring equipment. The method comprises obtaining a first distance measurement in a first location, then obtaining at least one other distance measurement in at least one other location of a precisely known distance from the first location, and calculating a calibration constant. The method is applied specifically to calculating a calibration constant for obtaining fluid level and embodied in an apparatus using a pressure transducer and a spacer of precisely known length. The calibration constant is used to calculate the depth of a fluid from subsequent single pressure measurements at any submerged position.

  11. Development of novel sol-gel indicators (SGI`s) for in-situ environmental measurements

    SciTech Connect

    Livingston, R.R.; Wicks, G.G.; Baylor, L.C.; Whitaker, M.J.

    1993-10-01

    Organic indicator molecules have been incorporated in a porous sol- gel matrix coated on the end of a fiber-optic lens assembly to create sensors for in situ environmental measurements. Probes have been made that are sensitive to pH and uranyl concentration. The use of fiber optics allows the probe to be lowered into a well or bore hole, while support equipment such as a spectrophotometer and computer may be situated hundreds of meters away.

  12. Quantitative measurements in in situ straining experiments in transmission electron microscopy.

    PubMed

    Pettinari, F; Couret, A; Caillard, D; Molénat, G; Clément, N; Coujou, A

    2001-07-01

    Several examples of recent studies by in situ straining experiments in a transmission electron microscope performed in the Toulouse group (France) are presented. In particular, quantitative measurements of the features of the dislocation motion are described. These examples deal with individual or collective propagation of dislocations, which are submitted to various types of obstacle. Different metallic materials are investigated: magnesium, intermetallics, aluminium alloys and gamma phase of a superalloy. PMID:11454154

  13. Experimental Development of a Novel Stress Sensor for in situ Stress Measurement

    SciTech Connect

    Polsky, Yarom; Lance, Michael J; Mattus, Catherine H; Daniels, Ryan J

    2016-01-01

    This paper will describe ongoing work to adapt a previously demonstrated method for measuring stress in ceramics to develop a borehole deployed in situ stress sensor. The method involves the use of a cementitious material which exhibits a strong piezo-spectroscopic stress response as a downhole stress gage. A description of the conceptual approach will be provided along with preliminary analysis and proof-of-concept laboratory results.

  14. Comparison of Pore Water Chemical Extracted by Different Forces with In-situ Properties

    NASA Astrophysics Data System (ADS)

    Ito, N.; Machida, I.; Marui, A.; Scheytt, T.; Hebig, K. H.

    2010-12-01

    Due to the difficulty involved for in-situ sampling of groundwater, pore water was extracted from rock core samples for chemical analysis. Available literature indicated that, the chemical constituents of pore water are affected by large extraction force. This study is therefore aimed at discussing the reason behind the change in pore water chemistry when samples are subjected to different extraction forces. The process involved extraction of pore water from sandstone core samples at different pF values by centrifuge method. The pF expresses the tension of water, retained in soil. It is the base 10 logarithm of tension, which is measured as a head of water head in centimeters. The samples of lengths 100 m each were obtained from three locations. Tracer test using Iodine was also conducted to remove pore water polluted by drilling water. Pore water was extracted from a total of 63 samples at three different values of pF (low: up to pF 2.3, medium: pF 2.3 - 3.9, high: pF 3.9 - 4.3). For each pF range the pore water was analyzed for major anions and cations. Results showed variation of ionic concentrations with pF and depth. The average concentrations rose with increase of pF in all ions except for potassium. Based on the concentration distribution of Ca2+, three zones could be defined: (1) Ca2+ concentration, which does not depend on pF, (2) Ca2+ concentration, which increases with the value of pF and (3) Ca2+ showing the same value for medium and high pF values. It is thus concluded that, water chemistry of deep pore water is likely to have reached equilibrium due to almost stagnant flow conditions, whereas shallow water is likely to participate in chemical interactions due to the relatively high flow velocity. The depths of the interfaces of these three zones are almost consistent with geological boundaries of weathered and fine sandstone and there is evidence of a relationship between pore water chemistry and physical rock properties. Using this knowledge, we

  15. Ionospheric scintillations and in-situ measurements at an auroral location in the European sector

    SciTech Connect

    Basu, S.; Basu, S.; MacKenzie, E.; Weimer, D.

    1987-05-01

    The orbiting HiLat satellite offered a unique opportunity for studying the ionospheric scintillation parameters in relation to the in-situ measurements of ionization density, drift velocity, field-aligned current, and particle precipitation during the sunspot minimum period. This paper discusses the results of such a morphological study based on observations at the auroral-oval station of Tromso, Norway. The dynamics of the spatial and temporal extent of this region are illustrated in the invariant latitude/magnetic local time grid. The geometrical enhancement of scintillations observed during the alignment of the propagation path with the local magnetic L-shell is shown to be the most consistent and conspicuous feature of scintillations in the nighttime auroral oval. The steepening of phase spectral slope in this region is indicative of the presence of L-shell aligned sheet-like irregularities at long scale lengths. The seasonal variational of total electron content (TEC) determined from the differential Doppler measurements of HiLat transmissions is discussed in relation to the in-situ density measurements at 830 km. The results are also utilized to illustrate the dependence of ionospheric structure parameters on short-term variability of solar activity during the sunspot minimum period. Special effort is made to illustrate that the joint study of scintillation/TEC and in-situ parameters provides an insight into the nature of magnetospheric coupling with the high-latitude ionosphere.

  16. Chemical isolation of quartz for measurement of in-situ-produced cosmogenic nuclides

    SciTech Connect

    Kohl, C.P.; Nishiizumi, K. )

    1992-09-01

    Measurement of cosmogenic nuclides produced in situ in terrestrial samples shows great potential as a tool for quantifying continental erosion rates, determining exposure ages of rocks, dating various geologic events, and elucidating past climates. An isolation method relying totally on chemical steps was developed to separate large quantities (10-200 g) of clean mono-minerallic quartz samples from a variety of terrestrial rocks and soils for the purpose of measuring [sup 10]Be (t[sub 1/2] = 1.5 Myr) and [sup 26]Al (t[sub 1/2] = 0.705 Myr) produced by cosmic rays in situ in the quartz phase. The procedure consists of grinding the sample, heating it in HCl, and treating it with a series of leaches using a dilute HF/HNO[sub 3] mixture in a heated ultrasonic tank. The purified quartz was also used for the measurements of in-situ-cosmic-ray-produced [sup 21]Ne and [sup 14]C (t[sub 1/2] = 5,730 yr). The method is applicable to any problem requiring purified quartz on a large scale.

  17. Extinction-to-Backscatter Ratios of Saharan Dust Layers Derived from In-Situ Measurements and CALIPSO Overflights During NAMMA

    NASA Technical Reports Server (NTRS)

    Omar, Ali H.; Liu, Zhaoyan; Vaughan, Mark A.; Hu, Yongxiang; Ismail, Syed; Powell, Kathleen A.; Winker, David M.; Trepte, Charles R.; Anderson, Bruce E.

    2010-01-01

    We determine the aerosol extinction-to-backscatter (Sa) ratios of dust using airborne in-situ measurements of microphysical properties, and CALIPSO observations during the NASA African Monsoon Multidisciplinary Analyses (NAMMA). The NAMMA field experiment was conducted from Sal, Cape Verde during Aug-Sept 2006. Using CALIPSO measurements of the attenuated backscatter of lofted Saharan dust layers, we apply the transmittance technique to estimate dust Sa ratios at 532 nm and a 2-color method to determine the corresponding 1064 nm Sa. Using this method, we found dust Sa ratios of 39.8 plus or minus 1.4 sr and 51.8 plus or minus 3.6 sr at 532 nm and 1064 nm, respectively. Secondly, Sa ratios at both wavelengths is independently calculated using size distributions measured aboard the NASA DC-8 and estimates of Saharan dust complex refractive indices applied in a T-Matrix scheme. We found Sa ratios of 39.1 plus or minus 3.5 sr and 50.0 plus or minus 4 sr at 532 nm and 1064 nm, respectively, using the T-Matrix calculations applied to measured size spectra. Finally, in situ measurements of the total scattering (550 nm) and absorption coefficients (532 nm) are used to generate an extinction profile that is used to constrain the CALIPSO 532 nm extinction profile.

  18. Soil Shear Properties Assessment, Resistance, Thermal, and Triboelectric Analysis (SPARTTA) Tool: A New Multitool Instrument for Identifying the Physical Properties of In-situ Soils on Planetary Surfaces.

    NASA Astrophysics Data System (ADS)

    Anderson, R. C.; Peters, G. H.; Beegle, L. W.; Zhou, Y. M.; Van Stryk, N.; Carey, E. M.

    2015-12-01

    SPARTTA is a low cost, low mass (< 1 kg), and low power (< 5 watt) deployable rover-arm mounted contact instrument that will provide a new capability for measurements of the physical properties of in-situ soils on a planetary surface. SPARTTA is TRL-4 and is able to characterize the mechanical (shear and compressive strength), thermal (conductivity), and electrical (dielectric spectroscopy and triboelectric charging) properties of soils through the integration of five specialized tools into a small, portable instrument, analogous to the Swiss army knife. All of the SPARTTA components are based on classical terrestrial soil analytical tools. Each component will be used to measure a specific physical property of a planetary regolith. SPARTTA will be easily adaptable to a wide range of surface environments for any future planetary robotic surface mission. A key innovation of SPARTTA is its state-of-the-art miniature packaging approach which enables in-situ comprehensive analyses of the physical properties of soils on any planetary body (e.g. asteroids, comets, etc.) with a single compact instrument. SPARTTA will specifically address several high-priority science goals identified in the Decadal Study regarding the physical properties of planetary soils, liquid water/water-ice detection, and electrostatics for bodies as diverse as comets, Trojan asteroids, Mars and the Moon [Planetary Science Decadal Study, 2013]. Additionally, it will provide valuable data to assist engineers in designing landing, drilling, coring, and sample acquisition systems for future Discovery, New Frontiers missions, or flagship landed missions.

  19. In-Situ Silver Acetylide Silver Nitrate Explosive Deposition Measurements Using X-Ray Fluorescence.

    SciTech Connect

    Covert, Timothy Todd

    2014-09-01

    The Light Initiated High Explosive facility utilized a spray deposited coating of silver acetylide - silver nitrate explosive to impart a mechanical shock into targets of interest. A diagnostic was required to measure the explosive deposition in - situ. An X - ray fluorescence spectrometer was deployed at the facility. A measurement methodology was developed to measure the explosive quantity with sufficient accuracy. Through the use of a tin reference material under the silver based explosive, a field calibration relationship has been developed with a standard deviation of 3.2 % . The effect of the inserted tin material into the experiment configuration has been explored.

  20. In situ exhaust cloud measurements. [particle size distribution and cloud physics of rocket exhaust clouds

    NASA Technical Reports Server (NTRS)

    Wornom, D.

    1980-01-01

    Airborne in situ exhaust cloud measurements were conducted to obtain definitions of cloud particle size range, Cl2 content, and HCl partitioning. Particle size distribution data and Cl2 measurements were made during the May, August, and September 1977 Titan launches. The measurements of three basic effluents - HCl, NO sub X, and particles - against minutes after launch are plotted. The maximum observed HCl concentration to the maximum Cl2 concentration are compared and the ratios of the Cl2 to the HCl is calculated.

  1. A Method to Measure the Flatness of the LSST Focal Plane Assembly in Situ

    SciTech Connect

    Langeveld, Willy; /SLAC

    2005-10-26

    In this note I describe an inexpensive and simple laser-based method to measure the flatness of the LSST focal plane assembly (FPA) in situ, i.e. while the FPA is inside its cryostat, at -100 C and under vacuum. The method may also allow measurement of the distance of the FPA to lens L3, and may be sensitive enough to measure gravity- and pressure-induced deformations of L3 as well. The accuracy of the method shows promise to be better than 1 micron.

  2. In situ global method for measurement of oxygen demand and mass transfer

    SciTech Connect

    Klasson, K.T.; Lundbaeck, K.M.O.; Clausen, E.C.; Gaddy, J.L.

    1997-05-01

    Two aerobic microorganisms, Saccharomycopsis lipolytica and Brevibacterium lactofermentum, have been used in a study of mass transfer and oxygen uptake from a global perspective using a closed gas system. Oxygen concentrations in the gas and liquid were followed using oxygen electrodes, and the results allowed for easy calculation of in situ oxygen transport. The cell yields on oxygen for S. lipolytica and B. lactofermentum were 1.01 and 1.53 g/g respectively. The mass transfer coefficient was estimated as 10 h{sup {minus}1} at 500 rpm for both fermentations. The advantages with this method are noticeable since the use of model systems may be avoided, and the in situ measurements of oxygen demand assure reliable data for scale-up.

  3. Outlet-glacier flow dynamics estimation combining in-situ and spaceborne SAR measurements

    NASA Astrophysics Data System (ADS)

    Rohner, Christoph; Henke, Daniel; Small, David; Mercenier, Rémy; Lüthi, Martin; Vieli, Andreas

    2016-04-01

    Terminus retreat and flow acceleration changes of ocean-terminating outlet glaciers contribute significantly to the current mass loss of the Greenland Ice Sheet and therefore to global sea level rise. In order to constrain models ice dynamics, detailed knowledge of geometry, ice-flow velocity and strain fields of such calving glaciers is needed. Of specific importance is the near terminus flow dynamics, as the flow fields there are highly influential on the glacier's calving rate. With the current temporal resolution of spaceborne radar systems, it is difficult to accurately capture the near terminus flow fields for fast moving outlet glaciers glaciers, while in-situ measurements using ground based radar interferometers are limited in coverage and constrained by distance and geometric shading of the glacier. We present and analyze the combined continuous velocity fields from a ground based, portable radar system as well as from spaceborne SAR scenes for Eqip Sermia, a medium-sized ocean terminating outlet glacier in western Greenland. The flow fields for the spaceborne data are calculated using feature tracking with a temporal resolution of 12 and 24 days for Sentinel-1 (Interferometric Wide Swath) and RADARSAT-2 (Ultra Fine/Fine Quad) respectively. The in-situ terrestrial radar data were recorded at one minute intervals were additionally processed using interferometry. The combination of in-situ and spaceborne radar enables a spatially continuous assessment of the strain fields of the ocean terminating outlet glacier. An assimilation of the data based on areas with both in-situ and spaceborne measurements is carried out and the results are compared to historical strain field data sets. These data ultimately provide constraints for a physical fracture and damage model.

  4. In situ measurements of organic matter dynamics during a storm event in an agricultural watershed

    NASA Astrophysics Data System (ADS)

    Pellerin, B. A.; Saraceno, J.; Downing, B. D.; Bachand, P. A.; Bergamaschi, B. A.

    2008-12-01

    Dissolved organic matter (DOM) from the breakdown of plant and animal material is a significant concern for drinking water quality in California due to the potential formation of carcinogenic disinfection byproducts during treatment. Winter storms are important forcing events on the California landscape, but the extent to which they impart rapid changes in DOM and other biogeochemical variables is poorly understood. In situ optical measurements are useful as they can be made autonomously at high temporal resolution, aiding in the quantification of rapid changes in the DOM pool. We collected in situ and discrete samples during a storm event period (Feb 22-March 3, 2008) at the mouth of the 415 km2 agricultural Willow Slough watershed. The watershed is characterized by steep grasslands in the headwaters and agriculture (largely in alfalfa, rice, tomato, grasses and orchard) in the valley. The in situ optical measurements included turbidity, chromophoric DOM fluorescence (cDOM), and nitrate (NO3-) concentrations, along with a suite of ancillary parameters. Discharge and turbidity were strongly correlated at peak flow and increased by over two orders of magnitude, while the peak cDOM lagged the peak in turbidity by ten hours. The cDOM values increased by nearly 4 fold and were highly correlated with dissolved organic carbon (DOC) concentrations (r2=0.97), providing a highly resolved proxy for DOC throughout the flow event. Specific UV absorbance (an indicator of DOM aromaticity) doubled at the DOC peak, while decreases in both the spectral slope (a proxy for DOM molecular weight) and δ13C-DOM during the same period support terrestrially- derived DOM contributions at peak flows. The lag to peak cDOM behind peak discharge presumably reflects the draining of watershed soils and delayed surface runoff of natural and agricultural landscapes. Together, laboratory and in situ data provide insights into the timing and magnitude of changes in DOM quantity and quality during

  5. Highly accurate isotope measurements of surface material on planetary objects in situ

    NASA Astrophysics Data System (ADS)

    Riedo, Andreas; Neuland, Maike; Meyer, Stefan; Tulej, Marek; Wurz, Peter

    2013-04-01

    Studies of isotope variations in solar system objects are of particular interest and importance. Highly accurate isotope measurements provide insight into geochemical processes, constrain the time of formation of planetary material (crystallization ages) and can be robust tracers of pre-solar events and processes. A detailed understanding of the chronology of the early solar system and dating of planetary materials require precise and accurate measurements of isotope ratios, e.g. lead, and abundance of trace element. However, such measurements are extremely challenging and until now, they never have been attempted in space research. Our group designed a highly miniaturized and self-optimizing laser ablation time-of-flight mass spectrometer for space flight for sensitive and accurate measurements of the elemental and isotopic composition of extraterrestrial materials in situ. Current studies were performed by using UV radiation for ablation and ionization of sample material. High spatial resolution is achieved by focusing the laser beam to about Ø 20μm onto the sample surface. The instrument supports a dynamic range of at least 8 orders of magnitude and a mass resolution m/Δm of up to 800—900, measured at iron peak. We developed a measurement procedure, which will be discussed in detail, that allows for the first time to measure with the instrument the isotope distribution of elements, e.g. Ti, Pb, etc., with a measurement accuracy and precision in the per mill and sub per mill level, which is comparable to well-known and accepted measurement techniques, such as TIMS, SIMS and LA-ICP-MS. The present instrument performance offers together with the measurement procedure in situ measurements of 207Pb/206Pb ages with the accuracy for age in the range of tens of millions of years. Furthermore, and in contrast to other space instrumentation, our instrument can measure all elements present in the sample above 10 ppb concentration, which offers versatile applications

  6. Development of a direct push based in-situ thermal conductivity measurement system

    NASA Astrophysics Data System (ADS)

    Chirla, Marian Andrei; Vienken, Thomas; Dietrich, Peter; Bumberger, Jan

    2016-04-01

    push based approaches, called Thermal Conductivity Profiler (TCP), that operates based on the principles of a hollow cylindrical geometry heat source. To determinate thermal conductivity in situ, the transient temperature at the middle of the probe and electrical power dissipation is measured. At the same time, this work presents laboratory results obtained when this novel hollow cylindrical probe system was tested on different materials for calibration. By using the hollow cylindrical probe, the thermal conductivity results have an error of less than 2.5% error for solid samples (Teflon, Agar jelly, and Nylatron). These findings are useful to achieve a proper thermal energy balance in the shallow subsurface by using direct push technology and TCP. By providing information of layers with high thermal conductivity, suitable for thermal storage capability, can be used determine borehole heat exchanger design and, therefore, determine geothermal heat pump architecture.

  7. Integrated Airborne and In-Situ Measurements Over Land-Fast Ice Near Barrow, AK.

    NASA Astrophysics Data System (ADS)

    Gardner, J. M.; Brozena, J. M.; Richter-Menge, J.; Abelev, A.; Liang, R.; Ball, D.; Claffey, K. J.; Hebert, D. A.; Jones, K.

    2015-12-01

    The Naval Research Laboratory has collected two field seasons of integrated airborne and in-situ measurements over multiple sites of floating, but land-fast ice north of Barrow, AK. During the first season in March of 2014 the Cold Regions Research and Engineering Laboratory led the on-ice group including NRL personnel and Naval Academy midshipmen. The second season (March 2015) included only NRL scientists and midshipmen. The in-situ data provided ground-truth for airborne measurements from a scanning LiDAR (Riegl Q 560i), digital photogrammetry (Applanix DSS-439), a low-frequency SAR (P-band in 2014 and P and L bands in 2015) and a snow/Ku radar procured from the Center for Remote Sensing of Ice Sheets of the University of Kansas. The CReSIS radar was updated in 2015 to integrate the snow and Ku radars into a single continuous chirp, thus improving resolution. The objective of the survey was to aid our understanding of the use of the airborne data to calibrate/validate Cryosat-2 data. Sampling size or "footprint" plays a critical role in the attempt to compare in-situ measurements with airborne (or satellite) measurements. Thus the in-situ data were arranged to minimize aliasing. Ground measurements were collected along transects a sites generally consisting of a 2 km long profile of Magnaprobe and EM31 measurements with periodic boreholes. A 60 m x 400 m swath of Magnaprobe measurements was centered on this profile. Airborne data were collected on multiple overflights of the transect areas. The LiDAR measured total freeboard (ice + snow) referenced to leads in the ice, and produced swaths 200-300 m wide. The SAR imaged the ice beneath the snow and the snow/Ku radar measured snow thickness. The freeboard measurements and snow thickness are used to estimate ice thickness via isostasy and density estimates. Comparisons and processing methodology will be shown. The results of this ground-truth experiment will inform our analysis of grids of airborne data collected

  8. An approach for measuring the thermal conductivity of in situ foamed insulated pipe transporting liquid nitrogen

    NASA Astrophysics Data System (ADS)

    Xu, Dong; Wu, Heng; Liu, Huiming; Gong, Linghui; Xu, Xiangdong; Li, L. F.

    2012-06-01

    The thermal conductivity of three foamed pipes has been tested for the development of liquid nitrogen transmission pipelines. By establishing a function between evaporation rate and thermal conductivity, we obtain effective thermal conductivity without destroying pipes. The comparison between our test and test coupons shows that this test device is reliable and could be a standard test for checking insulation properties of in situ foamed pipes transporting liquid nitrogen. The scientific principles, system design, experimental results and effect factors of the test are presented in this paper.

  9. 3D shape measurements with a single interferometric sensor for in-situ lathe monitoring

    NASA Astrophysics Data System (ADS)

    Kuschmierz, R.; Huang, Y.; Czarske, J.; Metschke, S.; Löffler, F.; Fischer, A.

    2015-05-01

    Temperature drifts, tool deterioration, unknown vibrations as well as spindle play are major effects which decrease the achievable precision of computerized numerically controlled (CNC) lathes and lead to shape deviations between the processed work pieces. Since currently no measurement system exist for fast, precise and in-situ 3d shape monitoring with keyhole access, much effort has to be made to simulate and compensate these effects. Therefore we introduce an optical interferometric sensor for absolute 3d shape measurements, which was integrated into a working lathe. According to the spindle rotational speed, a measurement rate of 2,500 Hz was achieved. In-situ absolute shape, surface profile and vibration measurements are presented. While thermal drifts of the sensor led to errors of several mµm for the absolute shape, reference measurements with a coordinate machine show, that the surface profile could be measured with an uncertainty below one micron. Additionally, the spindle play of 0.8 µm was measured with the sensor.

  10. Quantifying precision of in situ length and weight measurements of fish

    USGS Publications Warehouse

    Gutreuter, S.; Krzoska, D.J.

    1994-01-01

    We estimated and compared errors in field-made (in situ) measurements of lengths and weights of fish. We made three measurements of length and weight on each of 33 common carp Cyprinus carpio, and on each of a total of 34 bluegills Lepomis macrochirus and black crappies Pomoxis nigromaculatus. Maximum total lengths of all fish were measured to the nearest 1 mm on a conventional measuring board. The bluegills and black crappies (85–282 mm maximum total length) were weighed to the nearest 1 g on a 1,000-g spring-loaded scale. The common carp (415–600 mm maximum total length) were weighed to the nearest 0.05 kg on a 20-kg spring-loaded scale. We present a statistical model for comparison of coefficients of variation of length (Cl ) and weight (Cw ). Expected Cl was near zero and constant across mean length, indicating that length can be measured with good precision in the field. Expected Cw decreased with increasing mean length, and was larger than expected Cl by 5.8 to over 100 times for the bluegills and black crappies, and by 3 to over 20 times for the common carp. Unrecognized in situ weighing errors bias the apparent content of unique information in weight, which is the information not explained by either length or measurement error. We recommend procedures to circumvent effects of weighing errors, including elimination of unnecessary weighing from routine monitoring programs. In situ weighing must be conducted with greater care than is common if the content of unique and nontrivial information in weight is to be correctly identified.

  11. Analysis of In Situ Thermal Ion Measurements from the MICA Sounding Rocket

    NASA Astrophysics Data System (ADS)

    Fernandes, P. A.; Lynch, K. A.; Zettergren, M. D.; Hampton, D. L.; Fisher, L. E.; Powell, S. P.

    2014-12-01

    The MICA sounding rocket launched on 19 Feb. 2012 into several discrete, localized arcs in the wake of a westward traveling surge. In situ and ground-based observations provide a measured response of the ionosphere to preflight and localized auroral drivers. Initial analysis of the in situ thermal ion data indicate possible measurement of an ion conic at low altitude (< 325 km). In the low-energy regime, the response of the instrument varies from the ideal because the measured thermal ion population is sensitive to the presence of the instrument. The plasma is accelerated in the frame of the instrument due to flows, ram, and acceleration through the sheath which forms around the spacecraft. The energies associated with these processes are large compared to the thermal energy. Correct interpretation of thermal plasma measurements requires accounting for all of these plasma processes and the non-ideal response of the instrument in the low-energy regime. This is an experimental and modeling project which involves thorough analysis of ionospheric thermal ion data from the MICA campaign. Analysis includes modeling and measuring the instrument response in the low-energy regime as well as accounting for the complex sheath formed around the instrument. This results in a forward model in which plasma parameters of the thermal plasma are propagated through the sheath and instrument models, resulting in an output which matches the in situ measurement. In the case of MICA, we are working toward answering the question of the initiating source processes that result, at higher altitudes, in well-developed conics and outflow on auroral field lines.

  12. Validation of Land Surface Temperature products in arid climate regions with permanent in-situ measurements

    NASA Astrophysics Data System (ADS)

    Goettsche, F.; Olesen, F.; Trigo, I.; Hulley, G. C.

    2013-12-01

    Land Surface Temperature (LST) is operationally obtained from several space-borne sensors, e.g. from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) onboard Meteosat Second Generation (MSG) by the Land Surface Analysis - Satellite Application Facility (LSA-SAF) and from the Moderate Resolution Imaging Spectroradiometer (MODIS) on EOS-Terra by the MODIS Land Team. The relative accuracy of LST products can be assessed by cross-validating different products. Alternatively, the so-called 'radiance based validation' can be used to compare satellite-retrieved LST with results from radiative transfer models: however, this requires precise a priori knowledge of land surface emissivity (LSE) and atmospheric conditions. Ultimately, in-situ measurements (';ground truth') are needed for validating satellite LST&E products. Therefore, the LST product derived by LSA-SAF is validated with independent in-situ measurements (';temperature based validation') at permanent validation stations located in different climate regions on the SEVIRI disk. In-situ validation is largely complicated by the spatial scale mismatch between satellite sensors and ground based sensors, i.e. areas observed by ground radiometers usually cover about 10 m2, whereas satellite measurements in the thermal infrared typically cover between 1 km2 and 100 km2. Furthermore, an accurate characterization of the surface is critical for all validation approaches, but particularly over arid regions, as shown by in-situ measurements revealing that LSE products can be wrong by more than 3% [1]. The permanent stations near Gobabeb (Namibia; hyper-arid desert climate) and Dahra (Senegal; hot-arid steppe-prairie climate) are two of KIT's four dedicated LST validation stations. Gobabeb station is located on vast and flat gravel plains (several 100 km2), which are mainly covered by coarse gravel, sand, and desiccated grass. The gravel plains are highly homogeneous in space and time, which makes them ideal for

  13. Fabrication and Properties of Silicone RUBBER/ZnO Nanocomposites via in Situ Surface Hydrosilylation

    NASA Astrophysics Data System (ADS)

    Yuan, Zhijie; Zhou, Weihua; Hu, Ting; Chen, Yiwang; Li, Fan; Xu, Zhentian; Wang, Xiaofeng

    The silicone rubber (SR) nanocomposites have been successfully prepared via the in situ hydrosilylation reaction in the presence of pristine ZnO and vinyl silane modified ZnO (SiVi@ZnO) nanoparticles. The structure of the pristine ZnO and SiVi@ZnO nanoparticles were analyzed by the Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), respectively. The morphology, thermal stabilities, mechanical properties and thermal conductivity of the nanocomposites were also investigated. The results showed that the SiVi@ZnO nanoparticles exhibit a better dispersion in the silicone rubber than the pristine ZnO nanoparticles. The corresponding silicone rubber/SiVi@ZnO (SR/SiVi@ZnO) nanocomposites showed higher mechanical properties and thermal conductivity due to the better dispersion in silicone rubber matrix.

  14. In situ measurements of volatile aromatic hydrocarbon biodegradation rates in groundwater

    USGS Publications Warehouse

    Cozzarelli, I.M.; Bekins, B.A.; Eganhouse, R.P.; Warren, E.; Essaid, H.I.

    2010-01-01

    Benzene and alkylbenzene biodegradation rates and patterns were measured using an in situ microcosm in a crude-oil contaminated aquifer near Bemidji, Minnesota. Benzene-D6, toluene, ethylbenzene, o-, m- and p-xylenes and four pairs of C3- and C4-benzenes were added to an in situ microcosm and studied over a 3-year period. The microcosm allowed for a mass-balance approach and quantification of hydrocarbon biodegradation rates within a well-defined iron-reducing zone of the anoxic plume. Among the BTEX compounds, the apparent order of persistence is ethylbenzene > benzene > m,p-xylenes > o-xylene ≥ toluene. Threshold concentrations were observed for several compounds in the in situ microcosm, below which degradation was not observed, even after hundreds of days. In addition, long lag times were observed before the onset of degradation of benzene or ethylbenzene. The isomer-specific degradation patterns were compared to observations from a multi-year study conducted using data collected from monitoring wells along a flowpath in the contaminant plume. The data were fit with both first-order and Michaelis-Menten models. First-order kinetics provided a good fit for hydrocarbons with starting concentrations below 1 mg/L and Michaelis-Menten kinetics were a better fit when starting concentrations were above 1 mg/L, as was the case for benzene. The biodegradation rate data from this study were also compared to rates from other investigations reported in the literature.

  15. A comparison of analytical laboratory and optical in situ methods for the measurement of nitrate in north Florida water bodies

    NASA Astrophysics Data System (ADS)

    Rozin, A. G.; Clark, M. W.

    2013-12-01

    Assessing the impact of nutrient concentrations on aquatic ecosystems requires an in depth understanding of dynamic biogeochemical cycles that are often a challenge to monitor at the high spatial and temporal resolution necessary to understand these complex processes. Traditional sampling approaches involving discrete samples and laboratory analyses can be constrained by analytical costs, field time, and logistical details that can fail to accurately capture both spatial and temporal changes. Optical in situ instruments may provide the opportunity to continuously monitor a variety of water quality parameters at a high spatial or temporal resolution. This work explores the suitability of a Submersible Ultraviolet Nitrate Analyzer (SUNA), produced by Satlantic, to accurately assess in situ nitrate concentration in several freshwater systems in north Florida. The SUNA was deployed to measure nitrate at five different water bodies selected to represent a range of watershed land uses and water chemistry in the region. In situ nitrate measurements were compared to standard laboratory methods to evaluate the effectiveness of the SUNA's operation. Other optical sensors were used to measure the spectral properties of absorbance, fluorescence, and turbidity (scatter) in the same Florida water bodies. Data from these additional sensors were collected to quantify possible interferences that may affect SUNA performance. In addition, data from the SUNA and other sensors are being used to infer information about the quality and quantity of aqueous constituents besides nitrate. A better understanding of the capabilities and possible limitations of these relatively new analytical instruments will allow researchers to more effectively investigate biogeochemical processes and nutrient transport and enhance decision-making to protect our water bodies.

  16. Simulated plasma facing component measurements for an in situ surface diagnostic on Alcator C-Moda)

    NASA Astrophysics Data System (ADS)

    Hartwig, Z. S.; Whyte, D. G.

    2010-10-01

    The ideal in situ plasma facing component (PFC) diagnostic for magnetic fusion devices would perform surface element and isotope composition measurements on a shot-to-shot (˜10 min) time scale with ˜1 μm depth and ˜1 cm spatial resolution over large areas of PFCs. To this end, the experimental adaptation of the customary laboratory surface diagnostic—nuclear scattering of MeV ions—to the Alcator C-Mod tokamak is being guided by ACRONYM, a Geant4 synthetic diagnostic. The diagnostic technique and ACRONYM are described, and synthetic measurements of film thickness for boron-coated PFCs are presented.

  17. Measurement of 3-D hydraulic conductivity in aquifer cores at in situ effective stresses.

    PubMed

    Wright, Martin; Dillon, Peter; Pavelic, Paul; Peter, Paul; Nefiodovas, Andrew

    2002-01-01

    An innovative and nondestructive method to measure the hydraulic conductivity of drill core samples in horizontal and vertical directions within a triaxial cell has been developed. This has been applied to characterizing anisotropy and heterogeneity of a confined consolidated limestone aquifer. Most of the cores tested were isotropic, but hydraulic conductivity varied considerably and the core samples with lowest values were also the most anisotropic. Hydraulic conductivity decreased with increasing effective stress due to closure of microfractures caused by sampling for all core samples. This demonstrates the importance of replicating in situ effective stresses when measuring hydraulic conductivity of cores of deep aquifers in the laboratory. PMID:12236264

  18. In-situ x-ray measurements of pit solutions during localized corrosion

    SciTech Connect

    Cho, J.H.; Davenport, A.J.; Isaacs, H.S.

    1991-01-01

    In this work, in-situ x-ray absorption spectroscopy (XAS) measurements of the ion concentrations within an artificial pit are presented to study the ionic species present and mass transport phenomena during localized corrosion taking place on metal surfaces. The x-ray absorption by an element in a sample is markedly greater at an energy just above than just below one of its absorption edges and the energy of this edge is characteristic of the absorbing element. A pair of measurement above and below the edge serves to determine both the presence and the amount of the element sought. 9 refs., 3 figs.

  19. In situ measurement of group refractive index using tandem low-coherence interferometer

    NASA Astrophysics Data System (ADS)

    Matsumoto, H.; Sasaki, K.; Hirai, A.

    2006-10-01

    The group refractive index of BK-7 glass material is accurately measured using a tandem low-coherence interferometer, which is composed of a Mychelson interferometer and a Fizeau interferometer, within a combined standard uncertainty of 8.4 ppm. The experimental results are compared with the value calculated from the conventional data base on the phase refractive index, within a difference of about 4.7 ppm. This new method is applicable to in situ measurement due to the principle of its common optical path.

  20. The in-situ 3D measurement system combined with CNC machine tools

    NASA Astrophysics Data System (ADS)

    Zhao, Huijie; Jiang, Hongzhi; Li, Xudong; Sui, Shaochun; Tang, Limin; Liang, Xiaoyue; Diao, Xiaochun; Dai, Jiliang

    2013-06-01

    With the development of manufacturing industry, the in-situ 3D measurement for the machining workpieces in CNC machine tools is regarded as the new trend of efficient measurement. We introduce a 3D measurement system based on the stereovision and phase-shifting method combined with CNC machine tools, which can measure 3D profile of the machining workpieces between the key machining processes. The measurement system utilizes the method of high dynamic range fringe acquisition to solve the problem of saturation induced by specular lights reflected from shiny surfaces such as aluminum alloy workpiece or titanium alloy workpiece. We measured two workpieces of aluminum alloy on the CNC machine tools to demonstrate the effectiveness of the developed measurement system.

  1. Cone penetrometer deployed in situ video microscope for characterizing sub-surface soil properties

    SciTech Connect

    Lieberman, S.H.; Knowles, D.S.; Kertesz, J.

    1997-12-31

    In this paper we report on the development and field testing of an in situ video microscope that has been integrated with a cone penetrometer probe in order to provide a real-time method for characterizing subsurface soil properties. The video microscope system consists of a miniature CCD color camera system coupled with an appropriate magnification and focusing optics to provide a field of view with a coverage of approximately 20 mm. The camera/optic system is mounted in a cone penetrometer probe so that the camera views the soil that is in contact with a sapphire window mounted on the side of the probe. The soil outside the window is illuminated by diffuse light provided through the window by an optical fiber illumination system connected to a white light source at the surface. The video signal from the camera is returned to the surface where it can be displayed in real-time on a video monitor, recorded on a video cassette recorder (VCR), and/or captured digitally with a frame grabber installed in a microcomputer system. In its highest resolution configuration, the in situ camera system has demonstrated a capability to resolve particle sizes as small as 10 {mu}m. By using other lens systems to increase the magnification factor, smaller particles could be resolved, however, the field of view would be reduced. Initial field tests have demonstrated the ability of the camera system to provide real-time qualitative characterization of soil particle sizes. In situ video images also reveal information on porosity of the soil matrix and the presence of water in the saturated zone. Current efforts are focused on the development of automated imaging processing techniques as a means of extracting quantitative information on soil particle size distributions. Data will be presented that compares data derived from digital images with conventional sieve/hydrometer analyses.

  2. Methyl mercury dynamics in a tidal wetland quantified using in situ optical measurements

    USGS Publications Warehouse

    Bergamaschi, B.A.; Fleck, J.A.; Downing, B.D.; Boss, E.; Pellerin, B.; Ganju, N.K.; Schoellhamer, D.H.; Byington, A.A.; Heim, W.A.; Stephenson, M.; Fujii, R.

    2011-01-01

    We assessed monomethylmercury (MeHg) dynamics in a tidal wetland over three seasons using a novel method that employs a combination of in situ optical measurements as concentration proxies. MeHg concentrations measured over a single spring tide were extended to a concentration time series using in situ optical measurements. Tidal fluxes were calculated using modeled concentrations and bi-directional velocities obtained acoustically. The magnitude of the flux was the result of complex interactions of tides, geomorphic features, particle sorption, and random episodic events such as wind storms and precipitation. Correlation of dissolved organic matter quality measurements with timing of MeHg release suggests that MeHg is produced in areas of fluctuating redox and not limited by buildup of sulfide. The wetland was a net source of MeHg to the estuary in all seasons, with particulate flux being much higher than dissolved flux, even though dissolved concentrations were commonly higher. Estimated total MeHg yields out of the wetland were approximately 2.5 μg m?2 yr?1—4—40 times previously published yields—representing a potential loading to the estuary of 80 g yr?1, equivalent to 3% of the river loading. Thus, export from tidal wetlands should be included in mass balance estimates for MeHg loading to estuaries. Also, adequate estimation of loads and the interactions between physical and biogeochemical processes in tidal wetlands might not be possible without long-term, high-frequency in situ measurements.

  3. In situ method for real time measurement of dielectric film thickness in plasmas

    SciTech Connect

    Jang, Sung-Ho; Kim, Gun-Ho; Chung, Chin-Wook

    2010-01-15

    An in situ thickness measurement method of dielectric films (dual frequency method) was developed, and the thicknesses were measured in an inductively coupled plasma. This method uses a small ac bias voltage with two frequencies for thickness measurement. The dielectric thickness is obtained from measuring the amplitudes of the two frequency ac currents through a sensor, as well as using an equivalent circuit model describing impedance of the dielectric film and the plasma sheath. In the experiment, the thicknesses of Al{sub 2}O{sub 3} film could be accurately measured in real time. To check the measurement reliability, the dual frequency method was compared with reflection spectrophotometry as a technique for optical thickness diagnostics. It was found that the dual frequency method agrees closely with reflection spectrophotometry at various rf powers and pressures. In addition, this method is very simple and can be installed anywhere in plasma reactors, in contrast with optical methods; therefore, it is expected to be applied to in situ surface diagnostics for various processing plasmas.

  4. Insights from In-situ Measurements of Black Carbon During the Marine Stratus Experiment

    NASA Astrophysics Data System (ADS)

    Mazzoleni, C.; Dubey, M.; Chylek, P.; Arnott, P. W.; Seinfeld, J. H.; Varutbangkul, V.; Murphy, S. M.; Sorooshian, A.; Rissman, T. A.; Jonsson, H. H.; Buzorius, G.

    2005-12-01

    As part of DOE's marine stratus experiment (MASE) field campaign in Marina, CA a photoacoustic (PA) aerosol absorption instrument was deployed on the CIRPAS (Center for Interdisciplinary Remotely Piloted Aircraft Studies) Twin Otter during July 2005. The aim of these measurements was to elucidate aerosol processes regulating marine stratus clouds. Marine stratus play a dominant role in the Earth's radiative balance and improved stratus microphysical parameterizations are needed to quantify indirect effects of anthropogenic aerosols on climate. In particular, the effects of black carbon on clouds physical and optical properties are still poorly understood, and in-situ, real-time measurements can be used to improve our physical and chemical understanding. The PA instrument developed at the Desert Research Institute of Reno, NV was installed on board the Twin Otter airplane and flown over the Pacific Ocean near Monterey, CA in proximity of the California coast, where marine stratus are a common occurrence. The instrument measured simultaneously aerosol absorption and ~180° integrated scattering at 870nm. The aircraft carried other instrumentation that measured microphysical and chemical properties of aerosols and clouds. We report here a preliminary analysis of absorption and scattering measurements together with data from other on-board instruments. The aerosol absorption was often low and indistinguishable from instrumental noise (~0.6 Mm-1 for 2 minutes averages), indicating clean conditions resulting from the offshore flow and an extensive marine stratus deck. However, we sampled interesting short-term events with higher absorption and scattering values during almost every flight. Often these episodes were related to ship tracks and/or anthropogenic pollution from land. Our simultaneous measurements of absorption and scattering yielded a single scattering albedo (SSA) of about 0.75 to 1, which is consistent with previous studies. SSA values can give information

  5. Fiber based optical tweezers for simultaneous in situ force exertion and measurements in a 3D polyacrylamide gel compartment.

    PubMed

    Ti, Chaoyang; Thomas, Gawain M; Ren, Yundong; Zhang, Rui; Wen, Qi; Liu, Yuxiang

    2015-07-01

    Optical tweezers play an important role in biological applications. However, it is difficult for traditional optical tweezers based on objective lenses to work in a three-dimensional (3D) solid far away from the substrate. In this work, we develop a fiber based optical trapping system, namely inclined dual fiber optical tweezers, that can simultaneously apply and measure forces both in water and in a 3D polyacrylamide gel matrix. In addition, we demonstrate in situ, non-invasive characterization of local mechanical properties of polyacrylamide gel by measurements on an embedded bead. The fiber optical tweezers measurements agree well with those of atomic force microscopy (AFM). The inclined dual fiber optical tweezers provide a promising and versatile tool for cell mechanics study in 3D environments.

  6. Fiber based optical tweezers for simultaneous in situ force exertion and measurements in a 3D polyacrylamide gel compartment

    PubMed Central

    Ti, Chaoyang; Thomas, Gawain M; Ren, Yundong; Zhang, Rui; Wen, Qi; Liu, Yuxiang

    2015-01-01

    Optical tweezers play an important role in biological applications. However, it is difficult for traditional optical tweezers based on objective lenses to work in a three-dimensional (3D) solid far away from the substrate. In this work, we develop a fiber based optical trapping system, namely inclined dual fiber optical tweezers, that can simultaneously apply and measure forces both in water and in a 3D polyacrylamide gel matrix. In addition, we demonstrate in situ, non-invasive characterization of local mechanical properties of polyacrylamide gel by measurements on an embedded bead. The fiber optical tweezers measurements agree well with those of atomic force microscopy (AFM). The inclined dual fiber optical tweezers provide a promising and versatile tool for cell mechanics study in 3D environments. PMID:26203364

  7. Measurement of Synechococcus in situ growth rates using flow cytometry and rRNA-targeted probes. Final report

    SciTech Connect

    Chisholm, S.W.; Binder, B.J.

    1998-02-18

    The overall goal of this project was the development of methods for the estimation of in situ Synechococcus growth rates using flow cytometrically-measured cellular properties. As an important picoplanktonic primary producer, Synechococcus can be expected to significantly influence the cycling of carbon in coastal marine environments. Traditional methods for estimating growth rates in natural populations of these and other phytoplankton have relied upon bottle incubations, which take a long time to perform and are subject to a well known suite of artifactual bottle effects. The analytical approach the authors are developing would obviate the need for such incubations, thus avoiding bottle effects and allowing much higher sample through-put. Application of this approach to field populations of Synechococcus would contribute significantly to an understanding of the population dynamics of these organisms, and ultimately to an understanding of carbon cycling in coastal marine environments. The first step toward developing the proposed method for in situ growth rate determination is to establish the relationships between growth rate and cellular properties (e.g., cellular rRNA and DNA content) in Synechococcus strains growing under a variety of conditions. Establishing these relationships has been the focus of this project.

  8. ExoCube: In-Situ Measurement of Composition in the Exosphere, Thermosphere and Topside Ionosphere

    NASA Astrophysics Data System (ADS)

    Noto, J.; Waldrop, L.; Paschalidis, N.; Taylor, C.; Gardner, D. D.; Jones, S.; Rodriguez, M.; Nossal, S. M.; Mierkiewicz, E. J.; Puig-Suari, J.; Kerr, R.

    2014-12-01

    Quantification of neutral species densities in the upper thermosphere and lower exosphere remains elusive despite the analytical theories established by the pioneers of Aeronomy roughly fifty years ago, despite the evident requirements of Space Weather modeling, and despite the pragmatic reality of manned and unmanned spacecraft exploitation of the region. In fact, [O], [He] and [N2] have not been measured in-situ in the upper atmosphere since the era of DE-2, and then for only 18 months from 1981-1983 (near solar maximum). Prior to that, the Atmospheric Explorer program (AE-A launched in 1963, AE-E ended in 1980) provided the neutral density information upon which the MSIS model is largely based. No instrument has measured [H] in-situ, which is instead derived in MSIS by solution of the proton continuity equation.The ExoCube satellite provides a long-overdue benchmark for the densities of significant neutral and ionized species in the upper atmosphere, on a global scale, for the Space Weather and Aeronomy communities. These will be the first in-situ global neutral density data since DE-2, including the first direct measurements of [H] using a mass spectrometer technique. Since roughly half of the total electron column content (TEC) arises from photoionization of H, reliable knowledge of exospheric [H] is a crucial requirement of realistic Space Weather modeling of TEC. To insure that this project has enduring impact beyond the projected two-year duration of the satellite mission, experimental interaction with ground-based ISR and optical facilities is integrated. The simultaneous collection of ion and neutral densities will facilitate the use of ExoCube data for studies of charge exchange processes. Overpasses with observatories will enable ExoCube measurements to be used as a constraint for retrieval of density information from forward modeling of ground-based observations. Presented here will be the first post-launch mission status and operations.

  9. Advanced Soil Moisture Network Technologies; Developments in Collecting in situ Measurements for Remote Sensing Missions

    NASA Astrophysics Data System (ADS)

    Moghaddam, M.; Silva, A. R. D.; Akbar, R.; Clewley, D.

    2015-12-01

    The Soil moisture Sensing Controller And oPtimal Estimator (SoilSCAPE) wireless sensor network has been developed to support Calibration and Validation activities (Cal/Val) for large scale soil moisture remote sensing missions (SMAP and AirMOSS). The technology developed here also readily supports small scale hydrological studies by providing sub-kilometer widespread soil moisture observations. An extensive collection of semi-sparse sensor clusters deployed throughout north-central California and southern Arizona provide near real time soil moisture measurements. Such a wireless network architecture, compared to conventional single points measurement profiles, allows for significant and expanded soil moisture sampling. The work presented here aims at discussing and highlighting novel and new technology developments which increase in situ soil moisture measurements' accuracy, reliability, and robustness with reduced data delivery latency. High efficiency and low maintenance custom hardware have been developed and in-field performance has been demonstrated for a period of three years. The SoilSCAPE technology incorporates (a) intelligent sensing to prevent erroneous measurement reporting, (b) on-board short term memory for data redundancy, (c) adaptive scheduling and sampling capabilities to enhance energy efficiency. A rapid streamlined data delivery architecture openly provides distribution of in situ measurements to SMAP and AirMOSS cal/val activities and other interested parties.

  10. Effects of relative humidity on aerosol light scattering and its importance for the comparison of remote sensing with in-situ measurements

    NASA Astrophysics Data System (ADS)

    Zieger, Paul; Clemer, Katrijn; Yilmaz, Selami; Frieß, Udo; Irie, Hitoshi; Henzing, Bas; Fierz-Schmidhauser, Rahel; de Leeuw, Gerrit; Baltensperger, Urs; Weingartner, Ernest

    2010-05-01

    In the field, in-situ measurements of aerosol light scattering are often performed under dry conditions (relative humidity RH < 30-40%) which differ from the ambient ones. Since ambient aerosol particles experience a hygroscopic growth at enhanced RH, their micro physical and optical properties - especially the aerosol light scattering - are strongly dependent on RH. The knowledge of this RH effect is of eminent importance for climate forcing calculations or for the comparison of remote sensing with in-situ measurements. Here, we will present results from the Cabauw Intercomparison Campaign of Nitrogen Dioxide measuring Instruments (CINDI, June-July 2009, Cabauw, The Netherlands). During this campaign different remote sensing and in-situ instruments were used to derive atmospheric parameters mainly NO2 but also aerosol properties. The aerosol in-situ measurements were performed in the basement of the Cabauw tower (inlet height 60 m). The aerosol scattering coefficient was measured dry and at various, predefined RH conditions between 20 and 95% with a recently developed humidified nephelometer (WetNeph) and with a second nephelometer measuring at dry conditions. In addition, the aerosol absorption coefficient was measured by a multi-angle absorption photometer (MAAP). This combination of measurements allows the determination of the aerosol extinction coefficient at ambient RH. Three MAX-DOAS (multi-axis differential optical absorption spectroscopy) instruments retrieved vertical profiles of the aerosol extinction coefficient during CINDI. The retrieved aerosol extinction corresponding to the lowest profile layer can now be directly compared to the in-situ value, which is now re-calculated to ambient RH.

  11. The International Soil Moisture Network: a data hosting facility for global in situ soil moisture measurements

    NASA Astrophysics Data System (ADS)

    Dorigo, W. A.; Wagner, W.; Hohensinn, R.; Hahn, S.; Paulik, C.; Xaver, A.; Gruber, A.; Drusch, M.; Mecklenburg, S.; van Oevelen, P.; Robock, A.; Jackson, T.

    2011-05-01

    In situ measurements of soil moisture are invaluable for calibrating and validating land surface models and satellite-based soil moisture retrievals. In addition, long-term time series of in situ soil moisture measurements themselves can reveal trends in the water cycle related to climate or land cover change. Nevertheless, on a worldwide basis the number of meteorological networks and stations measuring soil moisture, in particular on a continuous basis, is still limited and the data they provide lack standardization of technique and protocol. To overcome many of these limitations, the International Soil Moisture Network (ISMN; http://www.ipf.tuwien.ac.at/insitu) was initiated to serve as a centralized data hosting facility where globally available in situ soil moisture measurements from operational networks and validation campaigns are collected, harmonized, and made available to users. Data collecting networks share their soil moisture datasets with the ISMN on a voluntary and no-cost basis. Incoming soil moisture data are automatically transformed into common volumetric soil moisture units and checked for outliers and implausible values. Apart from soil water measurements from different depths, important metadata and meteorological variables (e.g., precipitation and soil temperature) are stored in the database. These will assist the user in correctly interpreting the soil moisture data. The database is queried through a graphical user interface while output of data selected for download is provided according to common standards for data and metadata. Currently (status May 2011), the ISMN contains data of 19 networks and more than 500 stations located in North America, Europe, Asia, and Australia. The time period spanned by the entire database runs from 1952 until the present, although most datasets have originated during the last decade. The database is rapidly expanding, which means that both the

  12. The International Soil Moisture Network: a data hosting facility for global in situ soil moisture measurements

    NASA Astrophysics Data System (ADS)

    Dorigo, W. A.; Wagner, W.; Hohensinn, R.; Hahn, S.; Paulik, C.; Drusch, M.; Mecklenburg, S.; van Oevelen, P.; Robock, A.; Jackson, T.

    2011-02-01

    In situ measurements of soil moisture are invaluable for calibrating and validating land surface models and satellite-based soil moisture retrievals. In addition, long-term time series of in situ soil moisture measurements themselves can reveal trends in the water cycle related to climate or land cover change. Nevertheless, on a worldwide basis the number of meteorological networks and stations measuring soil moisture, in particular on a continuous basis, is still limited and the data they provide lack standardization of technique and protocol. To overcome many of these limitations, the International Soil Moisture Network (ISMN; http://www.ipf.tuwien.ac.at/insitu) was initiated to serve as a centralized data hosting facility where globally available in situ soil moisture measurements from operational networks and validation campaigns are collected, harmonized, and made available to users. Data collecting networks share their soil moisture datasets with the ISMN on a voluntary and no-cost basis. Incoming soil moisture data are automatically transformed into common volumetric soil moisture units and checked for outliers and implausible values. Apart from soil water measurements from different depths, important metadata and meteorological variables (e.g., precipitation and soil temperature) are stored in the database. These will assist the user in correctly interpreting the soil moisture data. The database is queried through a graphical user interface while output of data selected for download is provided according to common standards for data and metadata. Currently (status January 2011), the ISMN contains data of 16 networks and more than 500 stations located in the North America, Europe, Asia, and Australia. The time period spanned by the entire database runs from 1952 until the present, although most datasets have originated during the last decade. The database is rapidly expanding, which means that

  13. In situ Measurement of Pore-Water pH in Anoxic Sediments Using Laser Raman Spectrometry

    NASA Astrophysics Data System (ADS)

    Peltzer, E. T.; Luna, M.; Walz, P. M.; Zhang, X.; Brewer, P. G.

    2010-12-01

    Accurate measurement of the geochemical properties of sediment pore waters is of fundamental importance in ocean geochemistry and microbiology. Recent work has shown that the properties of pore waters can be measured rapidly in situ with a novel Raman based insertion probe (Zhang et al., 2010), and that data obtained from anoxic sediments on in situ dissolved methane concentrations are very different (~30x) than from recovered cores due the large scale degassing that occurs during core recovery (Zhang et al., submitted). Degassing of methane must carry with it via Henry’s Law partioning significant quantities of H2S, which is clearly detectable by smell during sample processing, and thus in situ measurement of H2S is also highly desirable. In practice, dissolved H2S is partitioned between the HS- and H2S species as a function of pH with pKa ~7 for the acid dissociation reaction. Since both species are Raman active full determination of the sulfide system is possible if the relative Raman cross sections are known. The diagenetic equations for these reactions are commonly summarized as: 2CH2O + SO4= ↔ 2HCO3- + H2S CH4 + SO4= ↔ HCO3- + HS- + H2O Three of the major components of these equations, CH4, SO4=, and H2S/HS-, are all observable directly by Raman spectroscopy; but the detection of HCO3- presents a challenge due to its low Raman cross section and thus poor sensitivity. We show that pore water pH, which is a good estimator of HCO3- if total CO2 or alkalinity are known, can be measured by observing the H2S / HS- ratio via the equation: pH = pKa + log([HS-]/[H2S]) thereby fully constraining these equations within a single measurement protocol. The Raman peak for HS- is at 2573 cm-1 and for H2S is at 2592 cm-1; thus the peaks are well separated and may easily be deconvoluted from the observed spectrum. We have determined the relative Raman cross sections by a series of laboratory measurements over a range of pH and by using the definition that when pH = p

  14. Return glider radiosonde for in situ upper-air research measurements

    NASA Astrophysics Data System (ADS)

    Kräuchi, Andreas; Philipona, Rolf

    2016-06-01

    Upper-air balloon soundings for weather predictions have been made since the beginning of the 20th century. New radiosonde instruments for in situ humidity-, radiation- and gas-profile measurements in the troposphere and the lower stratosphere, were introduced in recent years for atmospheric research and climate monitoring, but such instruments are often expensive and it is desired they be reused on multiple flights. Recovering instruments that freely descend with parachutes is time consuming, sometimes difficult and even dangerous. Here, we introduce the return glider radiosonde (RGR), which enables flying and retrieving valuable in situ upper-air instruments. The RGR is lifted with weather balloons similar to traditional radiosondes to a preset altitude, at which time a release mechanism cuts the tether string, and a built-in autopilot flies the glider autonomously back to the launch site or a desired preprogrammed location. Once the RGR reaches the landing coordinates it circles down and releases a parachute 100 m above ground for landing. The motivation for this project was to measure radiation profiles throughout the atmosphere with the same instrument multiple times and with a rapid turn-around time. The paper describes technical aspects of the return glider radiosonde and the built-in radiation instruments and shows test flights up to 24 km altitude that are analyzed in terms of flight performance and maximal distances covered. Several successive flights measuring radiation profiles demonstrate the reliability and the operational readiness of the RGR, allowing new ways for atmospheric in situ research and monitoring with payloads up to several kg depending on the specific size of the glider.

  15. A load-lock compatible system for in situ electrical resistivity measurements during thin film growth

    NASA Astrophysics Data System (ADS)

    Colin, J. J.; Diot, Y.; Guerin, Ph.; Lamongie, B.; Berneau, F.; Michel, A.; Jaouen, C.; Abadias, G.

    2016-02-01

    An experimental setup designed for in situ electrical resistance measurement during thin film growth is described. The custom-built sample holder with a four-point probe arrangement can be loaded into a high-vacuum magnetron sputter-deposition chamber through a load-lock transfer system, allowing measurements on series of samples without venting the main chamber. Electrical contact is ensured with circular copper tracks inserted in a Teflon plate on a mounting holder station inside the deposition chamber. This configuration creates the possibility to measure thickness-dependent electrical resistance changes with sub-monolayer resolution and is compatible with use of sample rotation during growth. Examples are presented for metallic films with high adatom mobility growing in a Volmer-Weber mode (Ag and Pd) as well as for refractory metal (Mo) with low adatom mobility. Evidence for an amorphous-to-crystalline phase transition at a film thickness of 2.6 nm is reported during growth of Mo on an amorphous Si underlayer, supporting previous findings based on in situ wafer curvature measurements.

  16. A load-lock compatible system for in situ electrical resistivity measurements during thin film growth.

    PubMed

    Colin, J J; Diot, Y; Guerin, Ph; Lamongie, B; Berneau, F; Michel, A; Jaouen, C; Abadias, G

    2016-02-01

    An experimental setup designed for in situ electrical resistance measurement during thin film growth is described. The custom-built sample holder with a four-point probe arrangement can be loaded into a high-vacuum magnetron sputter-deposition chamber through a load-lock transfer system, allowing measurements on series of samples without venting the main chamber. Electrical contact is ensured with circular copper tracks inserted in a Teflon plate on a mounting holder station inside the deposition chamber. This configuration creates the possibility to measure thickness-dependent electrical resistance changes with sub-monolayer resolution and is compatible with use of sample rotation during growth. Examples are presented for metallic films with high adatom mobility growing in a Volmer-Weber mode (Ag and Pd) as well as for refractory metal (Mo) with low adatom mobility. Evidence for an amorphous-to-crystalline phase transition at a film thickness of 2.6 nm is reported during growth of Mo on an amorphous Si underlayer, supporting previous findings based on in situ wafer curvature measurements. PMID:26931861

  17. In situ strain and temperature measurement and modelling during arc welding

    SciTech Connect

    Chen, Jian; Yu, Xinghua; Miller, Roger G.; Feng, Zhili

    2014-12-26

    In this study, experiments and numerical models were applied to investigate the thermal and mechanical behaviours of materials adjacent to the weld pool during arc welding. In the experiment, a new high temperature strain measurement technique based on digital image correlation (DIC) was developed and applied to measure the in situ strain evolution. In contrast to the conventional DIC method that is vulnerable to the high temperature and intense arc light involved in fusion welding processes, the new technique utilised a special surface preparation method to produce high temperature sustaining speckle patterns required by the DIC algorithm as well as a unique optical illumination and filtering system to suppress the influence of the intense arc light. These efforts made it possible for the first time to measure in situ the strain field 1 mm away from the fusion line. The temperature evolution in the weld and the adjacent regions was simultaneously monitored by an infrared camera. Finally and additionally, a thermal–mechanical finite element model was applied to substantiate the experimental measurement.

  18. In situ strain and temperature measurement and modelling during arc welding

    DOE PAGESBeta

    Chen, Jian; Yu, Xinghua; Miller, Roger G.; Feng, Zhili

    2014-12-26

    In this study, experiments and numerical models were applied to investigate the thermal and mechanical behaviours of materials adjacent to the weld pool during arc welding. In the experiment, a new high temperature strain measurement technique based on digital image correlation (DIC) was developed and applied to measure the in situ strain evolution. In contrast to the conventional DIC method that is vulnerable to the high temperature and intense arc light involved in fusion welding processes, the new technique utilised a special surface preparation method to produce high temperature sustaining speckle patterns required by the DIC algorithm as well asmore » a unique optical illumination and filtering system to suppress the influence of the intense arc light. These efforts made it possible for the first time to measure in situ the strain field 1 mm away from the fusion line. The temperature evolution in the weld and the adjacent regions was simultaneously monitored by an infrared camera. Finally and additionally, a thermal–mechanical finite element model was applied to substantiate the experimental measurement.« less

  19. In situ measurements of OH and HO{sub 2} in the upper troposphere and stratosphere

    SciTech Connect

    Wennberg, P.O.; Hanisco, T.F.; Cohen, R.C.

    1995-10-01

    Recent aircraft and balloon borne measurements of OH and HO{sub 2} are reviewed. The authors demonstrate the ability of the laser-induced fluorescence technique to provide accurate, high signal to noise ratio measurements of OH throughout the upper troposphere and stratosphere. HO{sub 2} is measured as OH after gas phase chemical titration with nitric oxide. The addition of the HO{sub x} measurement capability to the suite of instruments aboard the NASA ER-2 aircraft has provided a wealth of new information about the processes that determine the concentration of ozone in the lower stratosphere. These simultaneous, in situ measurements provide a unique test of present understanding of the mechanisms that control the odd-hydrogen chemistry of the lower atmosphere. 17 refs., 8 figs., 1 tab.

  20. Development of a Flight Instrument for in situ Measurements of Ethane and Methane

    NASA Astrophysics Data System (ADS)

    Wilkerson, J. P.; Sayres, D. S.; Anderson, J. G.

    2015-12-01

    Methane emissions data for natural gas and oil fields have high uncertainty. Better quantifying these emissions is crucial to establish an accurate methane budget for the United States. One obstacle is that these emissions often occur in areas near livestock facilities where biogenic methane abounds. Measuring ethane, which has no biogenic source, along with methane can tease these sources apart. However, ethane is typically measured by taking whole-air samples. This tactic has lower spatial resolution than making in situ measurements and requires the measurer to anticipate the location of emission plumes. This leaves unexpected plumes uncharacterized. Using Re-injection Mirror Integrated Cavity Output Spectroscopy (RIM-ICOS), we can measure both methane and ethane in flight, allowing us to establish more accurate fugitive emissions data that can more readily distinguish between different sources of this greenhouse gas.

  1. Cake properties in ultrafiltration of TiO2 fine particles combined with HA: in situ measurement of cake thickness by fluid dynamic gauging and CFD calculation of imposed shear stress for cake controlling.

    PubMed

    Du, Xing; Qu, Fangshu; Liang, Heng; Li, Kai; Chang, Haiqing; Li, Guibai

    2016-05-01

    In this study, the cake buildup of TiO2 fine particles in the presence of humid acid (HA) and cake layer controlling during ultrafiltration (UF) were investigated. Specifically, we measured the cake thickness using fluid dynamic gauging (FDG) method under various solution conditions, including TiO2 concentration (0.1-0.5 g/L), HA concentration (0-5 mg/L, total organic carbon (TOC)), and pH values (e.g., 4, 6 and 10), and calculated the shear stress distribution induced by stirring using computational fluid dynamics (CFD) to analyze the cake layer controlling conditions, including the operation flux (50-200 L m(-2) h(-1)) and TiO2 concentration (0.1-0.5 g/L). It was found that lower TiO2/HA concentration ratio could lead to exceedingly severe membrane fouling because of the formation of a relatively denser cake layer by filling the voids of cake layer with HA, and pH was essential for cake layer formation owing to the net repulsion between particles. Additionally, it was observed that shear stress was rewarding for mitigating cake growth under lower operation flux as a result of sufficient back-transport forces, and exhibited an excellent performance on cake layer controlling in lower TiO2 concentrations due to slight interaction forces on the vicinity of membrane.

  2. Development of scalable cook-off models using real-time in situ measurements.

    SciTech Connect

    Schmitt, Robert Gerard; Renlund, Anita Mariana; Erikson, William Wilding; Kaneshige, Michael Jiro

    2003-07-01

    Scalable thermal runaway models for cook-off of energetic materials (EMs) require realistic temperature- and pressure-dependent chemical reaction rates. The Sandia Instrumented Thermal Ignition apparatus was developed to provide in situ small-scale test data that address this model requirement. Spatially and temporally resolved internal temperature measurements have provided new insight into the energetic reactions occurring in PBX 9501, LX-10-2, and PBXN-109. The data have shown previously postulated reaction steps to be incorrect and suggest previously unknown reaction steps. Model adjustments based on these data have resulted in better predictions at a range of scales.

  3. Development of Scalable Cook-Off Models Using Real-Time In Situ Measurements

    NASA Astrophysics Data System (ADS)

    Kaneshige, M. J.; Renlund, A. M.; Schmitt, R. G.; Erikson, W. W.

    2004-07-01

    Scalable thermal runaway models for cook-off of energetic materials (EMs) require realistic temperature- and pressure-dependent chemical reaction rates. The Sandia Instrumented Thermal Ignition apparatus was developed to provide in situ small-scale test data that address this model requirement. Spatially and temporally resolved internal temperature measurements have provided new insight into the energetic reactions occurring in PBX 9501, LX-10-2, and PBXN-109. The data have shown previously postulated reaction steps to be incorrect and suggest previously unknown reaction steps. Model adjustments based on these data have resulted in better predictions at a range of scales.

  4. Dynamic in situ measurement of ablation rate in a composite rocket nozzle

    NASA Astrophysics Data System (ADS)

    Dean, Peter D.; Subbarao, E. R.; Smith, Marian

    1990-01-01

    This paper describes the development and calibration of an acoustic probe for dynamic in situ measurements of ablation rate in a composite rocket nozzle. The probe, which is to be inserted radially into the nozzle, is designed so that its end melts as the nozzle ablates. An ultrasonic transducer is used to launch an acoustic wave in the probe, and the length of the remaining probe is determined by analyzing the reflected pulses. The paper describes the probe test equipment, the criteria for material selection, the preliminary tests, and the analysis methodology. Results of experimental tests are presented.

  5. Measuring the in situ Kd of a genetically encoded Ca2+ sensor.

    PubMed

    Park, J Genevieve; Palmer, Amy E

    2015-01-05

    The use of genetically encoded Ca(2+) sensors (GECIs) for long-term monitoring of intracellular Ca(2+) has become increasingly common in the last decade. Emission-ratiometric GECIs, such as those in the Yellow Cameleon family, can be used to make quantitative measurements, meaning that their fluorescence signals can be converted to free Ca(2+) concentrations ([Ca(2+)]free). This conversion is only as accurate as the sensor's apparent dissociation constant for Ca(2+) (K'd), which depends on temperature, pH, and salt concentration. This protocol describes a method for performing a titration, in living cells (in situ), of cytosolic, nuclear, or mitochondrial sensors.

  6. Rapid In-Situ Measurement of Gamma Activity in Soil for Environmental Assessment

    NASA Astrophysics Data System (ADS)

    Honeycutt, T. K.

    2003-12-01

    In-situ measurements of gamma radiation in soil are used as a rapid, low-cost, non-intrusive alternative to conventional sampling and analysis methods in the preliminary assessment of environmental impacts to watersheds at the Savannah River Site (SRS). The method resolves the ambient gamma-radiation field near ground surface into background and residual components and provides radionuclide-specific soil activity determination. The efficacy of the method has been evaluated and compares favorably with conventional gamma-PHA soil analyses and aerial survey data. The method has garnered regulatory approval and is being successfully deployed to evaluate the impact of Cs-137 contamination from CERCLA sites.

  7. In situ measurements constraining the role of sulphate aerosols in mid-latitude ozone depletion

    NASA Technical Reports Server (NTRS)

    Fahey, D. W.; Kawa, S. R.; Woodbridge, E. L.; Tin, P.; Wilson, J. C.; Jonsson, H. H.; Dye, J. E.; Baumgardner, D.; Borrmann, S.; Toohey, D. W.

    1993-01-01

    In situ measurements of stratospheric sulphate aerosol, reactive nitrogen and chlorine concentrations at middle latitudes confirm the importance of aerosol surface reactions that convert active nitrogen to a less active, reservoir form. This makes mid-latitude stratospheric ozone less vulnerable to active nitrogen and more vulnerable to chlorine species. The effect of aerosol reactions on active nitrogen depends on gas phase reaction rates, so that increases in aerosol concentration following volcanic eruptions will have only a limited effect on ozone depletion at these latitudes.

  8. F4TCNQ-Induced Exciton Quenching Studied by Using in-situ Photoluminescence Measurements

    NASA Astrophysics Data System (ADS)

    Zhu, Jian; Lu, Min; Wu, Bo; Hou, Xiao-Yuan

    2012-09-01

    The role of F4TCNQ as an exciton quenching material in thin organic light-emitting films is investigated by means of in situ photoluminescence measurements. C60 was used as another quenching material in the experiment for comparison, with Alq3 as a common organic light-emitting material. The effect of the growth sequence of the materials on quenching was also examined. It is found that the radius of Förster energy transfer between F4TCNQ and Alq3 is close to 0 nm and Dexter energy transfer dominates in the quenching process.

  9. Investigation of three home-applied bleaching agents on enamel structure and mechanical properties: an in situ study

    NASA Astrophysics Data System (ADS)

    Sa, Yue; Wang, Zhejun; Ma, Xiao; Lei, Chang; Liang, Shanshan; Sun, Lili; Jiang, Tao; Wang, Yining

    2012-03-01

    The safety of at-home tooth bleaching, based upon carbamide peroxide (CP) or hydrogen peroxide (HP) as the active agent, has been questioned. The aim of the present study was to investigate the effects of three differently concentrated home-applied bleaching agents on human enamel under in situ conditions. Sixty specimens were divided randomly into four groups and treated with 10% CP, 15% CP, 20% CP, and distilled water, respectively. Raman spectroscopy, attenuated total reflectance-infrared (ATR-IR) spectroscopy, atomic force microscopy (AFM), microhardness, and fracture toughness (FT) measurements were conducted to determine variations on enamel structure and mechanical properties before and after the bleaching process. Raman revealed little variation of Raman relative intensity after treatment with CP, which was consistent with the results of ATR-IR, AFM, and microhardness analyses. In addition, laser-induced fluorescence (LIF) intensity, and FT showed significant decreases on CP-treated specimens. These findings suggested there were minimal demineralization effects of the three at-home bleaching agents on enamel in situ. However, the decrease of LIF intensity and FT on enamel seemed to be inevitable.

  10. In-situ application of Ultrasonic Pulse Velocity measurements to determine the degree of zeolitic alteration of ignimbrites

    NASA Astrophysics Data System (ADS)

    Evren Çubukçu, H.; Yurdakul, Yasin; Erkut, Volkan; Akkaş, Efe; Akın, Lütfiye; Ulusoy, İnan; Şen, Erdal

    2016-04-01

    The velocity of P-waves passing through a rock body is strongly dependent on the petrographical properties such as texture, crystallinity, porosity and fracture network. For this reason, the measurement of ultrasonic pulse velocities (UPV) has been widely used in various applications interested in mechanical properties of solid rock bodies. An ignimbrite is a deposit of pyroclastic density current originating from an explosive volcanic eruption and comprises of vitric volcanic ash, free crystals, juvenile magma fragments (pumice) and accidental xenoliths. The complex nature of the componentry of ignimbrites also exhibits spatial variation depending on the location of deposition. Furthermore, both syn- and post-depositional processes (i.e. welding, alteration etc.) may have drastic impact on the mechanical characteristics of the ignimbrites. Alteration can be defined as the devitrification and the crystallization of vitric components and the transformation of pre-existing minerals of the ignimbrite into new minerals under changing thermodynamic conditions. In this context, zeolitization is an alteration process in which metastable (vitric) components of an ignimbrite body are replaced by zeolite group of minerals under low temperature and pressure induced by hydrothermal activity. The crystallization of zeolite minerals in the pore space promotes an increase in crystallinity and therefore a decrease in porosity. Hence, the velocity of P-waves passing through a zeolitized ignimbrite will be considerably higher compared to those in unaltered counterparts. Within the scope of a TUBİTAK project (No:113Y439) in which the alteration properties of Cappadocian Ignimbrites (Nevşehir, Turkey) are being investigated, in-situ UPV measurements have been performed using a portable pulse test instrument. The acquired velocity data has been correlated with the modal proportions of secondary zeolite minerals obtained by SEM-EDS. The results demonstrate that the measured P

  11. An in-situ soil structure characterization methodology for measuring soil compaction

    NASA Astrophysics Data System (ADS)

    Dobos, Endre; Kriston, András; Juhász, András; Sulyok, Dénes

    2016-04-01

    The agricultural cultivation has several direct and indirect effects on the soil properties, among which the soil structure degradation is the best known and most detectable one. Soil structure degradation leads to several water and nutrient management problems, which reduce the efficiency of agricultural production. There are several innovative technological approaches aiming to reduce these negative impacts on the soil structure. The tests, validation and optimization of these methods require an adequate technology to measure the impacts on the complex soil system. This study aims to develop an in-situ soil structure and root development testing methodology, which can be used in field experiments and which allows one to follow the real time changes in the soil structure - evolution / degradation and its quantitative characterization. The method is adapted from remote sensing image processing technology. A specifically transformed A/4 size scanner is placed into the soil into a safe depth that cannot be reached by the agrotechnical treatments. Only the scanner USB cable comes to the surface to allow the image acquisition without any soil disturbance. Several images from the same place can be taken throughout the vegetation season to follow the soil consolidation and structure development after the last tillage treatment for the seedbed preparation. The scanned image of the soil profile is classified using supervised image classification, namely the maximum likelihood classification algorithm. The resulting image has two principal classes, soil matrix and pore space and other complementary classes to cover the occurring thematic classes, like roots, stones. The calculated data is calibrated with filed sampled porosity data. As the scanner is buried under the soil with no changes in light conditions, the image processing can be automated for better temporal comparison. Besides the total porosity each pore size fractions and their distributions can be calculated for

  12. In Situ Density Measurement of Basaltic Melts at High Pressure by X-ray Absorption Method

    NASA Astrophysics Data System (ADS)

    Ando, R.; Ohtani, E.; Suzuki, A.; Urakawa, S.; Katayama, Y.

    2004-12-01

    Density of silicate melt at high pressure is one of the most important properties to understand magma migration in the planetary interior. However, because of experimental difficulties, the density of magma at high pressure is poorly known. Katayama et al. (1996) recently developed a new in situ density measurement method for metallic melts, based on the density dependency of X-ray absorption in the sample. In this study, we tried to measure the density of basaltic melt by this absorption method. When X-ray is transmitted to the sample, the intensity of the transmitted X-ray beam (I) is expressed as follows; I=I0exp(-μ ρ t), where I0 is the intensity of incident X-ray beam, μ is the mass absorption coefficient, ρ is the density of the sample, and t is the thickness of the sample. If t and μ are known, we can determine the density of the sample by measuring I and I0. This is the principle of the absorption method for density measurement. In this study, in order to determine t, we used a single crystalline diamond cylinder as a sample capsule, diamond is less compressive and less deformable so that even at high pressure t (thickness of the sample at the point x) is expressed as follows; t = 2*(R02-x2)1/2, R0 is the inner radius of cylinder at the ambient condition, and x is distance from a center of the capsule. And diamond also shows less absorption so that this make it possible to measure the density of silicate melt with smaller absorption coefficient than metallic melts. In order to know the μ of the sample, we measured both densities (ρ ) and absorptions (I/I0) for some glasses and crystals with same composition of the sample at the ambient condition, and calculated as fallows; μ =ln(I/I0)/ρ . Experiments were made at the beamline (BL22XU) of SPring-8. For generation of high pressure and high temperature, we used DIA-type cubic anvil apparatus (SMAP180) there. We used tungsten carbide anvils with the edge-length of 6 mm. The energy of monochromatic X

  13. In situ stratospheric ozone measurements by long path UV absorption - Developments and interpretation

    NASA Technical Reports Server (NTRS)

    Weinstock, E. M.; Schiller, C. M.; Anderson, J. G.

    1986-01-01

    A high-sensitivity, in situ UV absorption ozone sensor has been developed for use in the stratosphere. The instrument couples 254-nm radiation from a low-pressure mercury discharge lamp into a 40-pass White cell to attain a high-sensitivity ozone absorption measurement. Preflight/postflight laboratory tests utilizing an ozone source coupled to a laboratory UV ozone photometer in a fast-flow system as well as in-flight diagnostics verify the successful operation of the instrument. Evidence is presented to verify that in situ UV absorption ozone photometers can measure stratospheric ozone with better than 3 percent precision and 5 percent accuracy, provided proper attention is given to both the thermal field surrounding the gondola and the ambient pressure measurements. Ozone data are compared with modeled profiles in the 28- to 40-km region. An assessment of the disagreement between observations and modeled profiles is given along with suggestions for future experiments designed to constrain photochemical models.

  14. Atmospheric methane at Zeppelin Station in Ny-Alesund: presentation and analysis of in situ measurements.

    PubMed

    Pedersen, Ine-Therese; Holmen, Kim; Hermansen, Ove

    2005-05-01

    In situ methane (CH(4)) measurement techniques and data from the Zeppelin Station in Ny-Alesund on Svalbard (N 78 degrees 54' E 11 degrees 53') on Mt. Zeppelin (475 m.a.s.l) are presented. The data span the time period from October 1998 to December 2003, though not continuously. The daily mean was calculated from 96 samples per day which are analysed by gas chromatography with flame ionisation detection. Details of the experimental methods and procedures are given. A harmonic function is fitted to the data with a constant trend and seasonal amplitude. The data are also presented in a regression plot showing the difference between the in situ measurements and flask measurements from the National Oceanic and Atmospheric Administration of the Climate Monitoring and Diagnostics Laboratory (NOAA/CMDL) in Boulder, Colorado (http://www.cmdl.noaa.gov/). The Zeppelin data show typical Arctic air characteristics with wintertime pollution episodes from Europe and Russia and a relatively calm summer state. PMID:15877171

  15. Atmospheric methane at Zeppelin Station in Ny-Alesund: presentation and analysis of in situ measurements.

    PubMed

    Pedersen, Ine-Therese; Holmen, Kim; Hermansen, Ove

    2005-05-01

    In situ methane (CH(4)) measurement techniques and data from the Zeppelin Station in Ny-Alesund on Svalbard (N 78 degrees 54' E 11 degrees 53') on Mt. Zeppelin (475 m.a.s.l) are presented. The data span the time period from October 1998 to December 2003, though not continuously. The daily mean was calculated from 96 samples per day which are analysed by gas chromatography with flame ionisation detection. Details of the experimental methods and procedures are given. A harmonic function is fitted to the data with a constant trend and seasonal amplitude. The data are also presented in a regression plot showing the difference between the in situ measurements and flask measurements from the National Oceanic and Atmospheric Administration of the Climate Monitoring and Diagnostics Laboratory (NOAA/CMDL) in Boulder, Colorado (http://www.cmdl.noaa.gov/). The Zeppelin data show typical Arctic air characteristics with wintertime pollution episodes from Europe and Russia and a relatively calm summer state.

  16. Image correlation method for measuring flow and diameter changes in contracting mesenteric microlymphatics in situ

    NASA Astrophysics Data System (ADS)

    Dixon, J. Brandon; Cote, Gerard; Gashev, Anatoly; Greiner, Steven; Moore, James; Zawieja, David

    2006-02-01

    Collecting microlymphatics play a vital role in promoting lymph flow from the initial lymphatics in the interstitial spaces to the large transport lymph ducts. In most tissues, the primary mechanism for producing this flow is the spontaneous contractions of the lymphatic wall. Individual units, known as lymphangion, are separated by valves that help prevent backflow when the vessel contracts, thus promoting flow through the lymphatic network. Lymphatic contractile activity is inhibited by flow in isolated lymphatics, however there are virtually no in situ measurements of lymph flow in these vessels. One of the difficulties associated with obtaining such measurements is the time consuming methods of manual particle tracking used previously by our group. Using an in situ preparation with mesenteric microlymphatics (~ 100 μm in diameter) and a high speed imaging system (500 fps), we have developed an image correlation method to measure lymphatic flow with a standard error of prediction of 0.3 mm/sec when compared with manual particle tracking.

  17. Testing coordinate measuring arms with a geometric feature-based gauge: in situ field trials

    NASA Astrophysics Data System (ADS)

    Cuesta, E.; Alvarez, B. J.; Patiño, H.; Telenti, A.; Barreiro, J.

    2016-05-01

    This work describes in detail the definition of a procedure for calibrating and evaluating coordinate measuring arms (AACMMs or CMAs). CMAs are portable coordinate measuring machines that have been widely accepted in industry despite their sensitivity to the skill and experience of the operator in charge of the inspection task. The procedure proposed here is based on the use of a dimensional gauge that incorporates multiple geometric features, specifically designed for evaluating the measuring technique when CMAs are used, at company facilities (workshops or laboratories) and by the usual operators who handle these devices in their daily work. After establishing the procedure and manufacturing the feature-based gauge, the research project was complemented with diverse in situ field tests performed with the collaboration of companies that use these devices in their inspection tasks. Some of the results are presented here, not only comparing different operators but also comparing different companies. The knowledge extracted from these experiments has allowed the procedure to be validated, the defects of the methodologies currently used for in situ inspections to be detected, and substantial improvements for increasing the reliability of these portable instruments to be proposed.

  18. In situ water vapor and ozone measurements in Lhasa and Kunming during the Asian summer monsoon

    NASA Astrophysics Data System (ADS)

    Bian, Jianchun; Pan, Laura L.; Paulik, Laura; Vömel, Holger; Chen, Hongbin; Lu, Daren

    2012-10-01

    The Asian summer monsoon (ASM) anticyclone circulation system is recognized to be a significant transport pathway for water vapor and pollutants to enter the stratosphere. The observational evidence, however, is largely based on satellite retrievals. We report the first coincident in situ measurements of water vapor and ozone within the ASM anticyclone. The combined water vapor and ozonesondes were launched from Kunming, China in August 2009 and Lhasa, China in August 2010. In total, 11 and 12 sondes were launched in Kunming and Lhasa, respectively. We present the key characteristics of these measurements, and provide a comparison to similar measurements from an equatorial tropical location, during the Tropical Composition, Cloud and Climate Coupling (TC4) campaign in July and August of 2007. Results show that the ASM anticyclone region has higher water vapor and lower ozone concentrations in the upper troposphere and lower stratosphere than the TC4 observations. The results also show that the cold point tropopause in the ASM region has a higher average height and potential temperature. The in situ observations therefore support the satellite-based conclusion that the ASM is an effective transport pathway for water vapor to enter stratosphere.

  19. Method for local temperature measurement in a nanoreactor for in situ high-resolution electron microscopy.

    PubMed

    Vendelbo, S B; Kooyman, P J; Creemer, J F; Morana, B; Mele, L; Dona, P; Nelissen, B J; Helveg, S

    2013-10-01

    In situ high-resolution transmission electron microscopy (TEM) of solids under reactive gas conditions can be facilitated by microelectromechanical system devices called nanoreactors. These nanoreactors are windowed cells containing nanoliter volumes of gas at ambient pressures and elevated temperatures. However, due to the high spatial confinement of the reaction environment, traditional methods for measuring process parameters, such as the local temperature, are difficult to apply. To address this issue, we devise an electron energy loss spectroscopy (EELS) method that probes the local temperature of the reaction volume under inspection by the electron beam. The local gas density, as measured using quantitative EELS, is combined with the inherent relation between gas density and temperature, as described by the ideal gas law, to obtain the local temperature. Using this method we determined the temperature gradient in a nanoreactor in situ, while the average, global temperature was monitored by a traditional measurement of the electrical resistivity of the heater. The local gas temperatures had a maximum of 56 °C deviation from the global heater values under the applied conditions. The local temperatures, obtained with the proposed method, are in good agreement with predictions from an analytical model. PMID:23831940

  20. Model-based aviation advice on distal volcanic ash clouds by assimilating aircraft in situ measurements

    NASA Astrophysics Data System (ADS)

    Fu, Guangliang; Heemink, Arnold; Lu, Sha; Segers, Arjo; Weber, Konradin; Lin, Hai-Xiang

    2016-07-01

    The forecast accuracy of distal volcanic ash clouds is important for providing valid aviation advice during volcanic ash eruption. However, because the distal part of volcanic ash plume is far from the volcano, the influence of eruption information on this part becomes rather indirect and uncertain, resulting in inaccurate volcanic ash forecasts in these distal areas. In our approach, we use real-life aircraft in situ observations, measured in the northwestern part of Germany during the 2010 Eyjafjallajökull eruption, in an ensemble-based data assimilation system combined with a volcanic ash transport model to investigate the potential improvement on the forecast accuracy with regard to the distal volcanic ash plume. We show that the error of the analyzed volcanic ash state can be significantly reduced through assimilating real-life in situ measurements. After a continuous assimilation, it is shown that the aviation advice for Germany, the Netherlands and Luxembourg can be significantly improved. We suggest that with suitable aircrafts measuring once per day across the distal volcanic ash plume, the description and prediction of volcanic ash clouds in these areas can be greatly improved.

  1. Utilizing In Situ Directional Hyperspectral Measurements to Validate Bio-Indicator Simulations for a Corn Crop Canopy

    NASA Technical Reports Server (NTRS)

    Cheng, Yen-Ben; Middleton, Elizabeth M.; Huemmrich, Karl F.; Zhang, Qingyuan; Campbell, Petya K. E.; Corp, Lawrence A.; Russ, Andrew L.; Kustas, William P.

    2010-01-01

    Two radiative transfer canopy models, SAIL and the two-layer Markov-Chain Canopy Reflectance Model (MCRM), were coupled with in situ leaf optical properties to simulate canopy-level spectral band ratio vegetation indices with the focus on the photochemical reflectance index in a cornfield. In situ hyperspectral measurements were made at both leaf and canopy levels. Leaf optical properties were obtained from both sunlit and shaded leaves. Canopy reflectance was acquired for eight different relative azimuth angles (psi) at three different view zenith angles (Theta (sub v)), and later used to validate model outputs. Field observations of photochemical reflectance index (PRI) for sunlit leaves exhibited lower values than shaded leaves, indicating higher light stress. Canopy PRI expressed obvious sensitivity to viewing geometry, as a function of both Theta (sub v) and psi . Overall, simulations from MCRM exhibited better agreements with in situ values than SAIL. When using only sunlit leaves as input, the MCRM-simulated PRI values showed satisfactory correlation and RMSE, as compared to in situ values. However, the performance of the MCRM model was significantly improved after defining a lower canopy layer comprised of shaded leaves beneath the upper sunlit leaf layer. Four other widely used band ratio vegetation indices were also studied and compared with the PRI results. MCRM simulations were able to generate satisfactory simulations for these other four indices when using only sunlit leaves as input; but unlike PRI, adding shaded leaves did not improve the performance of MCRM. These results support the hypothesis that the PRI is sensitive to physiological dynamics while the others detect static factors related to canopy structure. Sensitivity analysis was performed on MCRM in order to better understand the effects of structure related parameters on the PRI simulations. Leaf area index (LAI) showed the most significant impact on MCRM-simulated PRI among the parameters

  2. In Situ Roughness Measurements for the Solar Cell Industry Using an Atomic Force Microscope

    PubMed Central

    González-Jorge, Higinio; Alvarez-Valado, Victor; Valencia, Jose Luis; Torres, Soledad

    2010-01-01

    Areal roughness parameters always need to be under control in the thin film solar cell industry because of their close relationship with the electrical efficiency of the cells. In this work, these parameters are evaluated for measurements carried out in a typical fabrication area for this industry. Measurements are made using a portable atomic force microscope on the CNC diamond cutting machine where an initial sample of transparent conductive oxide is cut into four pieces. The method is validated by making a comparison between the parameters obtained in this process and in the laboratory under optimal conditions. Areal roughness parameters and Fourier Spectral Analysis of the data show good compatibility and open the possibility to use this type of measurement instrument to perform in situ quality control. This procedure gives a sample for evaluation without destroying any of the transparent conductive oxide; in this way 100% of the production can be tested, so improving the measurement time and rate of production. PMID:22319338

  3. In situ roughness measurements for the solar cell industry using an atomic force microscope.

    PubMed

    González-Jorge, Higinio; Alvarez-Valado, Victor; Valencia, Jose Luis; Torres, Soledad

    2010-01-01

    Areal roughness parameters always need to be under control in the thin film solar cell industry because of their close relationship with the electrical efficiency of the cells. In this work, these parameters are evaluated for measurements carried out in a typical fabrication area for this industry. Measurements are made using a portable atomic force microscope on the CNC diamond cutting machine where an initial sample of transparent conductive oxide is cut into four pieces. The method is validated by making a comparison between the parameters obtained in this process and in the laboratory under optimal conditions. Areal roughness parameters and Fourier Spectral Analysis of the data show good compatibility and open the possibility to use this type of measurement instrument to perform in situ quality control. This procedure gives a sample for evaluation without destroying any of the transparent conductive oxide; in this way 100% of the production can be tested, so improving the measurement time and rate of production. PMID:22319338

  4. Shared-earth models involving poroelastic wave propagation to estimate in-situ soil properties

    NASA Astrophysics Data System (ADS)

    Ghose, R.

    2011-12-01

    We propose a new concept, utilizing the underlying physical mechanism of frequency-dependent seismic wave propagation in the saturated near-surface soil, to combine transmission- and reflection-related attributes of different seismic wavetypes. This leads to accurate and stable estimates of in-situ soil properties e.g., permeability, porosity and stress, which are otherwise nearly impossible to estimate in undisturbed condition. These properties are important in hydrogeology, environmental and agricultural engineering, and geotechnical engineering. The proposed approach of integration based on the underlying physics differs conceptually from multidisciplinary integration performed at the interpretation stage or from stochastic inversion. The uniqueness and stability of the property estimates derive from the fact that we selectively use only those wave attributes and the differences in their respective underlying physics so that the integration benefits from the convexity that is present in the domain of the integrated soil properties. We find that even with the low frequency content typical of near-surface seismic data in soft soil and the uncertainties inherent to data and model, the approach is still quite robust. The results will be illustrated on synthetic, laboratory and field datasets.

  5. In situ biosensing of the nanomechanical property and electrochemical spectroscopy of Streptococcus mutans-containing biofilms

    NASA Astrophysics Data System (ADS)

    Haochih Liu, Bernard; Li, Kun-Lin; Kang, Kai-Li; Huang, Wen-Ke; Liao, Jiunn-Der

    2013-07-01

    This work presents in situ biosensing approaches to study the nanomechanical and electrochemical behaviour of Streptococcus mutans biofilms under different cultivation conditions and microenvironments. The surface characteristics and sub-surface electrochemistry of the cell wall of S. mutans were measured by atomic force microscopy (AFM) based techniques to monitor the in situ biophysical status of biofilms under common anti-pathogenic procedures such as ultraviolet (UV) radiation and alcohol treatment. The AFM nanoindentation suggested a positive correlation between nanomechanical strength and the level of UV radiation of S. mutans; scanning impedance spectroscopy of dehydrated biofilms revealed reduced electrical resistance that is distinctive from that of living biofilms, which can be explained by the discharge of cytoplasm after alcohol treatment. Furthermore, the localized elastic moduli of four regions of the biofilm were studied: septum (Z-ring), cell wall, the interconnecting area between two cells and extracellular polymeric substance (EPS) area. The results indicated that cell walls exhibit the highest elastic modulus, followed by Z-ring, interconnect and EPS. Our approach provides an effective alternative for the characterization of the viability of living cells without the use of biochemical labelling tools such as fluorescence dyeing, and does not rely on surface binding or immobilization for detection. These AFM-based techniques can be very promising approaches when the conventional methods fall short.

  6. In situ calibrated defocusing PTV for wall-bounded measurement volumes

    NASA Astrophysics Data System (ADS)

    Fuchs, T.; Hain, R.; Kähler, C. J.

    2016-08-01

    In many situations, 3D velocity measurements in thin (∼1 mm) but wide (∼100  ×  100 mm2) flow channels is an important task. To resolve the in-plane and out-of-plane velocity gradients properly, a precise calibration is required, since 3D measurement approaches rely strongly on the accuracy of the calibration procedure. It is likely that calibration targets do not fit domains with small depths, due to their size. Furthermore, in fields where such measurements are of interest, the accessibility of the measurement volume is often limited or even impossible. To overcome these drawbacks, this paper introduces an in situ calibrated defocusing particle tracking velocimetry approach for wall-bounded measurement domains with depths in the low millimeter range. The calibration function for the particle depth location is directly derived from the particle image geometries and their displacements between two frames. Employing only a single camera, this defocusing approach is capable of measuring the air flow between two parallel glass plates at a distance of 1 mm with an average uncertainty of 2.43% for each track, relative to the maximum velocity. A tomographic particle tracking velocimetry measurement, serving as a benchmark for the single camera technique, reaches an average uncertainty of 1.59%. Altogether, with its straightforward set-up and without requiring a calibration target, this in situ calibrated defocusing approach opens new areas of application for optical flow velocimetry. In particular, for measurement domains with small optical windows and a lack of accessibility.

  7. Combining data from lidar and in situ instruments to characterize the vertical structure of aerosol optical properties

    NASA Technical Reports Server (NTRS)

    Redemann, J.; Turco, R. P.; Pueschel, R. F.; Browell, E. V.; Grant, W. B.

    1998-01-01

    Over the last decade, the quantification of tropospheric aerosol abundance, composition and radiative impacts has become an important research endeavor. For the most part, the interest in tropospheric aerosols is derived from questions related to the global and local (instantaneous) radiative forcing of climate due to these aerosols. One approach is to study local forcing under well-defined conditions, and to extrapolate such results to global scales. To estimate local aerosol forcing, appropriate radiative transfer models can be employed (e.g., the Fu-Liou radiative transfer code, [Fu and Liou, 1993]). In general, such models require information on derived aerosol properties [Toon, 1994]; namely the aerosol optical depth, single-scattering albedo, and asymmetry factor (phase function), all of which appear in the equations of radiative transfer. In this paper, we report on a method that utilizes lidar data and in situ aerosol size distribution measurements to deduce the vertical structure of the aerosol complex index of refraction in the near IR, thus identifying the aerosol type. Together with aerosol size distributions obtained in situ, the aerosol refractive index can be used to calculate the necessary derived aerosol properties. The data analyzed here were collected during NASA's PEM West-B (Pacific Exploratory Mission) experiment, which took place in February/March 1994. The platform for the measurements was the NASA DC-8 aircraft. The primary goal of the PEM West missions [Browell et al., 1996] was the assessment of potential anthropogenic perturbations of the chemistry in the Pacific Basin troposphere. For this purpose the timing of PEM West-B corresponded to the seasonal peak in transport from the Asian continent into the Pacific basin [Merrill et al., in press]. This period normally occurs during Northern Hemisphere spring, when the Japan jet is well developed.

  8. In situ time-series measurements of subseafloor sediment properties

    USGS Publications Warehouse

    Wheatcroft, R.A.; Stevens, A.W.; Johnson, R.V.

    2007-01-01

    The capabilities and diversity of subsurface sediment sensors lags significantly from what is available for the water column, thereby limiting progress in understanding time-dependent seabed exchange and high-frequency acoustics. To help redress this imbalance, a new instrument, the autonomous sediment profiler (ASP), is described herein. ASP consists of a four-electrode, Wenner-type resistivity probe and a thermistor that log data at 0.1-cm vertical intervals over a 58-cm vertical profile. To avoid resampling the same spot on the seafloor, the probes are moved horizontally within a 20 times 100-cm-2 area in one of three preselected patterns. Memory and power capacities permit sampling at hourly intervals for up to 3-mo duration. The system was tested in a laboratory tank and shown to be able to resolve high-frequency sediment consolidation, as well as changes in sediment roughness. In a field test off the southern coast of France, the system collected resistivity and temperature data at hourly intervals for 16 d. Coupled with environmental data collected on waves, currents, and suspended sediment, the ASP is shown to be useful for understanding temporal evolution of subsurface sediment porosity, although no large depositional or erosional events occurred during the deployment. Following a rapid decrease in bottom-water temperature, the evolution of the subsurface temperature field was consistent with the 1-D thermal diffusion equation coupled with advection in the upper 3-4 cm. Collectively, the laboratory and field tests yielded promising results on time-dependent seabed change.

  9. Using continuous in-situ measurements to adaptively trigger urban storm water samples

    NASA Astrophysics Data System (ADS)

    Wong, B. P.; Kerkez, B.

    2015-12-01

    Until cost-effective in-situ sensors are available for biological parameters, nutrients and metals, automated samplers will continue to be the primary source of reliable water quality measurements. Given limited samples bottles, however, autosamplers often obscure insights on nutrient sources and biogeochemical processes which would otherwise be captured using a continuous sampling approach. To that end, we evaluate the efficacy a novel method to measure first-flush nutrient dynamics in flashy, urban watersheds. Our approach reduces the number of samples required to capture water quality dynamics by leveraging an internet-connected sensor node, which is equipped with a suite of continuous in-situ sensors and an automated sampler. To capture both the initial baseflow as well as storm concentrations, a cloud-hosted adaptive algorithm analyzes the high-resolution sensor data along with local weather forecasts to optimize a sampling schedule. The method was tested in a highly developed urban catchment in Ann Arbor, Michigan and collected samples of nitrate, phosphorus, and suspended solids throughout several storm events. Results indicate that the watershed does not exhibit first flush dynamics, a behavior that would have been obscured when using a non-adaptive sampling approach.

  10. In situ growth rate measurement and nucleation enhancement for microwave plasma CVD of diamond

    NASA Astrophysics Data System (ADS)

    Stoner, B. R.; Williams, B. E.; Wolter, S. D.; Nishimura, K.; Glass, J. T.

    1992-02-01

    Laser reflection interferometry (LRI) has been shown to be a useful in situ technique for measuring growth rate of diamond during microwave plasma chemical vapor deposition (MPCVD). Current alternatives to LRI usually involve ex situ analysis such as cross-sectional SEM or profilometry. The ability to measure the growth rate in 'real-time' has allowed the variation of processing parameters during a single deposition and thus the extraction of much more information in a fraction of the time. In situ monitoring of growth processes also makes it possible to perform closed loop process control with better reproducibility and quality control. Unfortunately, LRI requires a relatively smooth surface to avoid surface scattering and the commensurate drop in reflected intensity. This problem was remedied by greatly enhancing the diamond particle nucleation via the deposition of an intermediate carbon layer using substrate biasing. When an unscratched silicon wafer is pretreated by biasing negatively relative to ground while in a methane-hydrogen plasma, nucleation densities much higher than those achieved on scratched silicon wafers are obtained. The enhanced nucleation allows a complete film composed of small grains to form in a relatively short time, resulting in a much smoother surface than is obtained from a film grown at lower nucleation densities.

  11. In-situ Stress Measurement of MOVPE Growth of High Efficiency Lattice-Mismatched Solar Cells

    SciTech Connect

    Geisz, J. F.; Levander, A. X.; Norman, A. G.; Jones, K. M.; Romero, M. J.

    2007-04-01

    We have recently reported high efficiencies in a monolithic III-V triple-junction solar cell design that is grown inverted with a metamorphic 1.0 eV bottom In{sub .27}Ga{sub .73}As junction. The biaxial stress and strain grown into this highly lattice-mismatched junction can be controlled by varying the design of a step-graded Ga{sub x}In{sub 1-x}P buffer layer, in which most, but not all, of the 1.9% misfit strain is relieved. A multi-beam optical stress sensor (MOSS) is a convenient tool for in situ measurement of stress during metal-organic vapor phase epitaxy (MOVPE) for the optimization of solar cell performance. The analysis of stress from curvature data is complicated by significant temperature effects due to relatively small thermal gradients in our atmospheric-pressure MOVPE reactor. These temperature effects are discussed and approximations made to allow practical analysis of the data. The results show excellent performance of inverted In{sub .27}Ga{sub .73}. As solar cells grown with slight compressive stress, but degradation under tensile stress. The best devices had a V{sub oc} of 0.54 V and a dislocation density in the low 10{sup 6} cm{sup -2}. The in situ stress data is also compared with ex situ strain data derived from X-ray diffraction measurements.

  12. Quantitative electrochemical measurements using in situ ec-S/TEM devices.

    PubMed

    Unocic, Raymond R; Sacci, Robert L; Brown, Gilbert M; Veith, Gabriel M; Dudney, Nancy J; More, Karren L; Walden, Franklin S; Gardiner, Daniel S; Damiano, John; Nackashi, David P

    2014-04-01

    Insight into dynamic electrochemical processes can be obtained with in situ electrochemical-scanning/transmission electron microscopy (ec-S/TEM), a technique that utilizes microfluidic electrochemical cells to characterize electrochemical processes with S/TEM imaging, diffraction, or spectroscopy. The microfluidic electrochemical cell is composed of microfabricated devices with glassy carbon and platinum microband electrodes in a three-electrode cell configuration. To establish the validity of this method for quantitative in situ electrochemistry research, cyclic voltammetry (CV), choronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) were performed using a standard one electron transfer redox couple [Fe(CN)6]3-/4--based electrolyte. Established relationships of the electrode geometry and microfluidic conditions were fitted with CV and chronoamperometic measurements of analyte diffusion coefficients and were found to agree with well-accepted values that are on the order of 10-5 cm2/s. Influence of the electron beam on electrochemical measurements was found to be negligible during CV scans where the current profile varied only within a few nA with the electron beam on and off, which is well within the hysteresis between multiple CV scans. The combination of experimental results provides a validation that quantitative electrochemistry experiments can be performed with these small-scale microfluidic electrochemical cells provided that accurate geometrical electrode configurations, diffusion boundary layers, and microfluidic conditions are accounted for.

  13. Remote sensing of a comet nucleus with Rosetta/ROSINA in-situ coma measurements.

    NASA Astrophysics Data System (ADS)

    Dhooghe, Frederik; De Keyser, Johan

    2013-04-01

    Rosetta will rendez-vous with comet 67P/Churyumov-Gerasimenko in 2014 and will, among other tasks, study the physicochemical evolution of the cometary coma from onset of activity at large solar distances through perihelion at 1.2 AU. The Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) allows the determination of both neutrals and positive ions in the coma. This research effort is focused on using in situ gas density measurements at small distances from the nucleus to get information about gas production rates and volatile composition at the nucleus, which reveals information about the nucleus and its origin. Furthermore, if sufficient data is available, a 2D activity map of the nucleus surface can be created and inputs concerning the nucleus surface can be valuable to assist in finding a suitable landing location for Philae, the Rosetta lander. The volatile outgassing rate and the surface composition at the nucleus can be accurately determined from in situ coma composition measurements provided accurate information is available concerning solar activity, the flow field and reactions that transform the neutral gas as it expands outward (e.g. photo-ionization). This contribution describes the principle of the data inversion technique and illustrates it with model data.

  14. Theoretical and Experimental Errors for In Situ Measurements of Plant Water Potential 1

    PubMed Central

    Shackel, Kenneth A.

    1984-01-01

    Errors in psychrometrically determined values of leaf water potential caused by tissue resistance to water vapor exchange and by lack of thermal equilibrium were evaluated using commercial in situ psychrometers (Wescor Inc., Logan, UT) on leaves of Tradescantia virginiana (L.). Theoretical errors in the dewpoint method of operation for these sensors were demonstrated. After correction for these errors, in situ measurements of leaf water potential indicated substantial errors caused by tissue resistance to water vapor exchange (4 to 6% reduction in apparent water potential per second of cooling time used) resulting from humidity depletions in the psychrometer chamber during the Peltier condensation process. These errors were avoided by use of a modified procedure for dewpoint measurement. Large changes in apparent water potential were caused by leaf and psychrometer exposure to moderate levels of irradiance. These changes were correlated with relatively small shifts in psychrometer zero offsets (−0.6 to −1.0 megapascals per microvolt), indicating substantial errors caused by nonisothermal conditions between the leaf and the psychrometer. Explicit correction for these errors is not possible with the current psychrometer design. PMID:16663701

  15. In-situ multi-information measurement system for preparing gallium nitride photocathode

    NASA Astrophysics Data System (ADS)

    Fu, Xiao-Qian; Chang, Ben-Kang; Qian, Yun-Sheng; Zhang, Jun-Ju

    2012-03-01

    We introduce the first domestic in-situ multi-information measurement system for a gallium nitride (GaN) photocathode. This system can successfully fulfill heat cleaning and activation for GaN in an ultrahigh vacuum environment and produce a GaN photocathode with a negative electron affinity (NEA) status. Information including the heat cleaning temperature, vacuum degree, photocurrent, electric current of cesium source, oxygen source, and the most important information about the spectral response, or equivalently, the quantum efficiency (QE) can be obtained during preparation. The preparation of a GaN photocathode with this system indicates that the optimal heating temperature in a vacuum is about 700 °C. We also develop a method of quickly evaluating the atomically clean surface with the vacuum degree versus wavelength curve to prevent possible secondary contamination when the atomic level cleaning surface is tested with X-ray photoelectron spectroscopy. The photocurrent shows a quick enhancement when the current ratio between the cesium source and oxygen source is 1.025. The spectral response of the GaN photocathode is flat in a wavelength range from 240 nm to 365 nm, and an abrupt decline is observed at 365 nm, which demonstrates that with the in-situ multi-information measurement system the NEA GaN photocathode can be successfully prepared.

  16. In situ current voltage measurements for optimization of a novel fullerene acceptor in bulk heterojunction photovoltaics

    SciTech Connect

    Shuttle, Christopher G.; Treat, Neil D.; Fan, Jian; Varotto, Alessandro; Hawker, Craig J.; Wudl, Fred; Chabinyc, Michael L.

    2011-10-31

    The evaluation of the power conversion efficiency (PCE) of new materials for organic bulk heterojunction (BHJ) photovoltaics is difficult due to the large number of processing parameters possible. An efficient procedure to determine the optimum conditions for thermal treatment of polymer-based bulk heterojunction photovoltaic devices using in situ current-voltage measurements is presented. The performance of a new fullerene derivative, 1,9-dihydro-64,65-dihexyloxy-1,9-(methano[1,2] benzomethano)fullerene[60], in BHJ photovolatics with poly(3-hexylthiophene) (P3HT) was evaluated using this methodology. The device characteristics of BHJs obtained from the in situ method were found to be in good agreement with those from BHJs annealed using a conventional process. This fullerene has similar performance to 1-(3-methoxycarbonyl)propyl-1-phenyl-[6,6]-methano fullerene in BHJs with P3HT after thermal annealing. For devices with thickness of 70 nm, the short circuit current was 6.24 mA/cm² with a fill factor of 0.53 and open circuit voltage of 0.65 V. The changes in the current-voltage measurements during thermal annealing suggest that the ordering process in P3HT dominates the improvement in power conversion efficiency.

  17. Correlations between in situ sensor measurements and trace organic pollutants in urban streams.

    PubMed

    Henjum, Michael B; Hozalski, Raymond M; Wennen, Christine R; Arnold, William; Novak, Paige J

    2010-01-01

    Quantification of organic and microbial pollutant loading is expensive and labor-intensive because collection and analysis of grab samples are needed. Instruments are available, however, for in situ analysis of basic water quality parameters at high temporal resolution. Throughout the late summer and fall of 2008 a two-node water quality monitoring network was deployed to measure turbidity, specific conductance, pH, depth, temperature, dissolved oxygen, and nitrate at high frequencies in two urban streams in the Minneapolis, MN metropolitan area. Grab samples also were collected at 2 h intervals for 22 h during two dry periods and five rain events and analyzed for organic and microbial pollutants. This study investigated the viability of using in situ near real-time sensors to predict fecal coliforms, prometon (a residential herbicide), atrazine (an agricultural herbicide), and caffeine (a wastewater indicator) concentrations. Such pollutants can be used as indicators of sources that contribute to what is often termed "urban stream syndrome." At one stream, linear correlations were observed between nitrate and caffeine (R(2) = 0.66), turbidity and prometon (R(2) = 0.91), and discharge and prometon (R(2) = 0.92). At another location, caffeine linearly correlated with specific conductance (R(2) = 0.64). A lack of correlation with sensed water quality parameters was also observed with some of the pollutants. When one considers that error is estimated to be as high as 200% when using monthly grab samples to estimate pollutant loading in streams, even moderate correlations, such as the ones found in this study, can provide better loading estimates if frequently sensed parameters can be used for load estimation. Therefore, such site-specific relationships can be used to estimate the loading of specific pollutants in near real-time until robust low-cost technologies to analyze these pollutants in situ become available.

  18. Development of a Cone Penetrometer for Measuring Spectral Characteristics of Soils in Situ

    NASA Technical Reports Server (NTRS)

    Lee, Landris T., Jr.; Malone, Philip G.

    1993-01-01

    A patent was recently granted to the U.S. Army for an adaptation of a soil cone penetrometer that can be used to measure the spectral characteristics (fluorescence or reflectance) of soils adjacent to the penetrometer rod. The system can use a variety of light sources and spectral analytical equipment. A laser induced fluorescence measuring system has proven to be of immediate use in mapping the distribution of oil contaminated soil at waste disposal and oil storage areas. The fiber optic adaptation coupled with a cone penetrometer permits optical characteristics of the in-situ soil to be measured rapidly, safely, and inexpensively. The fiber optic cone penetrometer can be used to gather spectral data to a depth of approximately 25 to 30 m even in dense sands or stiff clays and can investigate 300 m of soil per day. Typical detection limits for oil contamination in sand is on the order of several hundred parts per million.

  19. Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in situ tunability

    NASA Astrophysics Data System (ADS)

    Palmer, A.; Silevitch, D. M.; Feng, Yejun; Wang, Yishu; Jaramillo, R.; Banerjee, A.; Ren, Y.; Rosenbaum, T. F.

    2015-09-01

    We discuss techniques for performing continuous measurements across a wide range of pressure-field-temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide range of pressure, while at the same time making possible precise steps across abrupt phase transitions such as those from insulator to metal.

  20. In situ measurements of the sub-surface gamma dose from Chernobyl fallout.

    PubMed

    Timms, D N; Smith, J T; Coe, E; Kudelsky, A V; Yankov, A I

    2005-06-01

    Methods of estimating external radiation exposure of soil-dwelling organisms are currently of much research and regulatory interest. In this paper, we report the first in situ measurements of the sub-surface gamma dose rate for 137Cs contaminated land that quantify variation in dose rate with depth. Two contrasting sites have been investigated. The first site comprised a mineral type soil with a low percentage of organic matter and the second site chosen was in a peat-bog. The different soil compositions afford different 137Cs mobility and this results in variations in the measured gamma dose-rate with soil depth. For each site the paper reports the measured dose rates, the 137Cs activity depth profile, the 137Cs inventory and a description of the soil-characteristics. It is suggested that these data can be used to produce estimates of the sub-surface gamma dose rate in other sites of 137Cs contamination. PMID:15799871

  1. In situ measurements of contributions to the global electrical circuit by a thunderstorm in southeastern Brazil

    USGS Publications Warehouse

    Thomas, J.N.; Holzworth, R.H.; McCarthy, M.P.

    2009-01-01

    The global electrical circuit, which maintains a potential of about 280??kV between the earth and the ionosphere, is thought to be driven mainly by thunderstorms and lightning. However, very few in situ measurements of electrical current above thunderstorms have been successfully obtained. In this paper, we present dc to very low frequency electric fields and atmospheric conductivity measured in the stratosphere (30-35??km altitude) above an active thunderstorm in southeastern Brazil. From these measurements, we estimate the mean quasi-static conduction current during the storm period to be 2.5 ?? 1.25??A. Additionally, we examine the transient conduction currents following a large positive cloud-to-ground (+ CG) lightning flash and typical - CG flashes. We find that the majority of the total current is attributed to the quasi-static thundercloud charge, rather than lightning, which supports the classical Wilson model for the global electrical circuit.

  2. In Situ Stress Measurements in the NPR Hole, Volume I - Results and Interpretations

    SciTech Connect

    Moos, D.

    2001-10-15

    This report presents the results of an investigation of the magnitudes and orientations of the in situ stresses in basement rocks beneath the Savannah River Site (SRS). Stress magnitudes were measured using the hydraulic fracturing technique. Stress orientations were obtained from the orientation of stress-induced wellbore breakouts and hydraulically-induced fractures. The measurements reported here were carried out in the New Production Reactor (NPR) hole, drilled to a total depth of 4000 feet near the center of the Savannah River Site, at roughly the location of the proposed NPR. The results obtained in this study are compared to previous stress measurements made using the same techniques in a series of shallower holes on the SRS, and discussed in the context of the regional stress field and potential seismic hazard.

  3. In situ Measurements of Irradiation-Induced Creep of Nanocrystalline Copper at Elevated Temperatures

    NASA Astrophysics Data System (ADS)

    Özerİnç, Sezer; Averback, Robert S.; King, William P.

    2016-08-01

    We have measured irradiation-induced creep on nanocrystalline copper micropillars at elevated temperatures. The micropillars, which were ≈1 µm in diameter and ≈2 µm in height, were fabricated from magnetron-sputtered nanocrystalline copper films. The micropillars were compressed during 2.0 MeV Ar+ bombardment and the deformation measured in situ by laser interferometry. The creep rate was measured over the stress range 10-120 MPa at ≈200°C. The results show linear relationships of creep rate with both applied stress and displacement rate, yielding a creep compliance of 0.07 dpa-1 GPa-1 (dpa:displacement per atom). The findings are in good agreement with the previous results obtained using a bulge test on free-standing thin film specimens.

  4. Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in situ tunability.

    PubMed

    Palmer, A; Silevitch, D M; Feng, Yejun; Wang, Yishu; Jaramillo, R; Banerjee, A; Ren, Y; Rosenbaum, T F

    2015-09-01

    We discuss techniques for performing continuous measurements across a wide range of pressure-field-temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide range of pressure, while at the same time making possible precise steps across abrupt phase transitions such as those from insulator to metal. PMID:26429451

  5. Quantifying Stratospheric Ozone in the Upper Troposphere Using in situ Measurements of HCl

    SciTech Connect

    Atherton, C S; Bergmann, D J; Marcy, T P; Fahey, D W; Gao, R S; Popp, P J; Richard, E C; Thompson, T L; Rosenlof, K H; Ray, E A; Salawitch, R J; Ridley, B A; . Weinheimer, A J; Loewenstein, M; Weinstock, E M; Mahoney, M J

    2004-03-08

    A chemical ionization mass spectrometry (CIMS) technique has been developed for precise in situ measurements of hydrochloric acid (HCl) from a high-altitude aircraft. In measurements at subtropical latitudes, minimum HCl values found in the upper troposphere (UT) are often near or below the 0.005-ppbv detection limit of the measurements, indicating that background HCl values are much lower than a global mean estimate. However, significant abundances of HCl were observed in many UT air parcels as a result of stratosphere-to-troposphere transport events. A method for diagnosing the amount of stratospheric ozone in these UT parcels was developed using the compact linear correlation of HCl with ozone found throughout the lower stratosphere (LS). Expanded use of this method will lead to improved quantification of cross-tropopause transport events and validation of global chemical transport models.

  6. Note: In situ measurement of vacuum window birefringence by atomic spectroscopy

    SciTech Connect

    Steffen, Andreas; Alt, Wolfgang; Genske, Maximilian; Meschede, Dieter; Robens, Carsten; Alberti, Andrea

    2013-12-15

    We present an in situ method to measure the birefringence of a single vacuum window by means of microwave spectroscopy on an ensemble of cold atoms. Stress-induced birefringence can cause an ellipticity in the polarization of an initially linearly polarized laser beam. The amount of ellipticity can be reconstructed by measuring the differential vector light shift of an atomic hyperfine transition. Measuring the ellipticity as a function of the linear polarization angle allows us to infer the amount of birefringence Δn at the level of 10{sup −8} and identify the orientation of the optical axes. The key benefit of this method is the ability to separately characterize each vacuum window, allowing the birefringence to be precisely compensated in existing vacuum apparatuses.

  7. Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in situ tunability

    SciTech Connect

    Palmer, A; Silevitch, D M; Feng, Yejun; Wang, Y; Jaramillo, R.; Banerjee, A.; Ren, Y.; Rosenbaum, T. F.

    2015-09-01

    We discuss techniques for performing continuous measurements across a wide range of pressure–field–temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide range of pressure, while at the same time making possible precise steps across abrupt phase transitions such as those from insulator to metal.

  8. Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in situ tunability.

    PubMed

    Palmer, A; Silevitch, D M; Feng, Yejun; Wang, Yishu; Jaramillo, R; Banerjee, A; Ren, Y; Rosenbaum, T F

    2015-09-01

    We discuss techniques for performing continuous measurements across a wide range of pressure-field-temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide range of pressure, while at the same time making possible precise steps across abrupt phase transitions such as those from insulator to metal.

  9. In situ measurements of KZ and ɛ compared to numerical models in the Gulf of Lion.

    NASA Astrophysics Data System (ADS)

    Costa, Andrea; Doglioli, Andrea; Dekeyser, Ivan; Jullion, Loic; Malengros, Deny; Petrenko, Anne

    2015-04-01

    Vertical diffusivity and turbulent kinetic energy dissipation rate play an essential role in the parametrization of physical and biogeochemical models. Coastal environment is particularly important because expected to contribute in a substantial way to the balance of kinetic energy in the ocean. In situ measurements have a crucial importance in driving the models. We present a multi-annual dataset performed with SCAMP (Self Contained Autonomous Profiler) field measurements of KZ and ɛ in a variety of meteorological and oceanic conditions in the Gulf of Lion (Mediterranean Sea). The results are compared with respect to similar measurements in coastal waters described in literature. Moreover, a comparison to numerical circulation models is proposed in order to show the dependency of the depth of the mixing layer on the wind forcing.

  10. Validation of AIRS Retrievals of CO2 via Comparison to In Situ Measurements

    NASA Technical Reports Server (NTRS)

    Olsen, Edward T.; Chahine, Moustafa T.; Chen, Luke L.; Jiang, Xun; Pagano, Thomas S.; Yung, Yuk L.

    2008-01-01

    Topics include AIRS on Aqua, 2002-present with discussion about continued operation to 2011 and beyond and background, including spectrum, weighting functions, and initialization; comparison with aircraft and FTIR measurements in Masueda (CONTRAIL) JAL flask measurements, Park Falls, WI FTIR, Bremen, GDF, and Spitsbergen, Norway; AIRS retrievals over addition FTIR sites in Darwin, AU and Lauder, NZ; and mid-tropospheric carbon dioxide weather and contribution from major surface sources. Slide titles include typical AIRS infrared spectrum, AIRS sensitivity for retrieving CO2 profiles, independence of CO2 solution with respect to the initial guess, available in situ measurements for validation and comparison, comparison of collocated V1.5x AIRS CO2 (N_coll greater than or equal to 9) with INTEX-NA and SPURT;

  11. In Situ Observations of the Microphysical Properties of Subvisible Cirrus during CR- AVE

    NASA Astrophysics Data System (ADS)

    Lawson, P.; Baker, B.; Pilson, B.; Mo, Q.; Jensen, E.

    2006-12-01

    In situ microphysical observations of subvisible cirrus between 8 degrees north latitude and the equator were collected using the NASA WB-57F research aircraft during the Costa Rica - Aura Validation Experiment (CR- AVE) in January 2006. Subvisible cirrus was commonly observed between 75 and 85 C (about 16 and 18 km). The observations included ice particle size, shape, concentration and relative humidity. Instrumentation included a cloud particle imager (CPI), a 2D-S (stereo) probe, a forward and backward scattering probe (CAS) and a tunable diode laser (TDL) water vapor probe. These are the first in situ observations that include a large dataset of digital images of the size and shape of ice particles in tropical subvisible cirrus. The images reveal that 84 percent of the ice particles are quasi-spherical in shape, with only a small percentage of the crystals exhibiting crystalline shapes (e.g., plates and columns), and virtually no trigonal particles, contrary to the only other crystal shape measurements collected in 1973. The particle size distribution suggests a monotonic distribution ranging from a few microns out to 120 microns in diameter. In the denser regions of cloud, mean particle concentrations were on the order of 20 to 40 per liter, mean extinction 0.004 inverse kilometers, and mean ice water content 0.02 mg per cubic meter. The ice particles are almost always observed when the ambient relative humidity is between 140 and 200 percent w.r.t. ice. Particle growth simulations suggest that ice particles in subvisible cirrus require very high (order 200 percent ice saturation) relative humidity to grow to 100 microns. The unique ice particle measurements in subvisible cirrus are useful in constraining water vapor measurements, validation of satellite retrievals and in parameterizations of radiation models.

  12. Quantification of L-band InSAR coherence over volcanic areas using LiDAR and in situ measurements

    NASA Astrophysics Data System (ADS)

    Arab-Sedze, Melanie; Heggy, Essam; Bretard, Frederic; Berveiller, Daniel; Jacquemoud, Stephane

    2014-07-01

    Interferometric Synthetic Aperture Radar (InSAR) is a powerful tool to monitor large-scale ground deformation at active volcanoes. However, vegetation and pyroclastic deposits degrade the radar coherence and therefore the measurement of 3-D surface displacements. In this article, we explore the complementarity between ALOS - PALSAR coherence images, airborne LiDAR data and in situ measurements acquired over the Piton de La Fournaise volcano (Reunion Island, France) to determine the sources of errors that may affect repeat-pass InSAR measure- ments. We investigate three types of surfaces: terrains covered with vegetation, lava flows (a'a, pahoehoe or slabby pahoehoe lava flows) and pyroclastic deposits (lapilli). To explain the loss of coherence observed over the Dolomieu crater between 2008 and 2009, we first use laser altimetry data to map topographic variations. The LiDAR intensity, which depends on surface reflectance, also provides ancillary information about the potential sources of coherence loss. In addition, surface roughness and rock dielectric properties of each terrain have been determined in situ to better understand how electromagnetic waves interact with such media: rough and porous surfaces, such as the a'a lava flows, produce a higher coherence loss than smoother surfaces, such as the pahoehoe lava flows. Variations in dielectric properties suggest a higher penetration depth in pyroclasts than in lava flows at L-band frequency. Decorrelation over the lapilli is hence mainly caused by volumetric effects. Finally, a map of LAI (Leaf Area Index) produced using SPOT 5 imagery allows us to quantify the effect of vegeta- tion density: radar coherence is negatively correlated with LAI and is unreliable for values higher than 7.5.

  13. Satellite (Timed, Aura, Aqua) and In Situ (Meteorological Rockets, Balloons) Measurement Comparability

    NASA Technical Reports Server (NTRS)

    Schmidlin, F. J.; Goldberg, Richard A.; Feofilov, A.; Rose, R.

    2010-01-01

    Measurements using the inflatable falling sphere often are requested to provide density data in support of special sounding rocket launchings into the mesosphere and thermosphere. To insure density measurements within narrow time frames and close in space, the inflatable falling sphere is launched within minutes of the major test. Sphere measurements are reliable for the most part, however, availability of these rocket systems has become more difficult and, in fact, these instruments no longer are manufactured resulting in a reduction of the meager stockpile of instruments. Sphere measurements also are used to validate remotely measured temperatures and have the advantage of measuring small-scale atmospheric features. Even so, with the dearth of remaining falling spheres perhaps it is time to consider whether the remote measurements are mature enough to stand alone. Presented are two field studies, one in 2003 from Northern Sweden and one in 2010 from the vicinity of Kwajalein Atoll that compare temperature retrievals between satellite and in situ failing spheres. The major satellite instruments employed are SABER, MLS, and AIRS. The comparisons indicate that remotely measured temperatures mimic the sphere temperature measurements quite well. The data also confirm that satellite retrievals, while not always at the exact location required for individual studies, are adaptable enough and highly useful. Although the falling sphere will provide a measurement at a specific location and time, satellites only pass a given location daily or less often. This report reveals that averaged satellite measurements can provide temperatures and densities comparable to the falling sphere.

  14. Satellite (Timed, Aura, Aqua) and In Situ (Meteorological Rockets, Balloons) Measurement Comparability

    NASA Astrophysics Data System (ADS)

    Schmidlin, F. J.; Goldberg, R. A.; Feofilov, A.; Rose, R.

    2010-12-01

    Measurements using the inflatable falling sphere often are requested to provide density data in support of special sounding rocket launchings into the mesosphere and thermosphere. To insure density measurements within narrow time frames and close in space, the inflatable falling sphere is launched within minutes of the major test. Sphere measurements are reliable for the most part, however, availability of these rocket systems has become more difficult and, in fact, these instruments no longer are manufactured resulting in a reduction of the meager stockpile of instruments. Sphere measurements also are used to validate remotely measured temperatures and have the advantage of measuring small-scale atmospheric features. Even so, with the dearth of remaining falling spheres perhaps it is time to consider whether the remote measurements are mature enough to stand alone. Presented are two field studies, one in 2003 from Northern Sweden and one in 2010 from the vicinity of Kwajalein Atoll that compare temperature retrievals between satellite and in situ falling spheres. The major satellite instruments employed are SABER, MLS, and AIRS. The comparisons indicate that remotely measured temperatures mimic the sphere temperature measurements quite well. The data also confirm that satellite retrievals, while not always at the exact location required for individual studies, are adaptable enough and highly useful. Although the falling sphere will provide a measurement at a specific location and time, satellites only pass a given location daily or less often. This report reveals that averaged satellite measurements can provide temperatures and densities comparable to the falling sphere.

  15. Galileo in-situ dust measurements and the sculpting of Jupiter's gossamer rings by its shadow

    NASA Astrophysics Data System (ADS)

    Krüger, Harald; Hamilton, Douglas P.; Moissl, Richard; Grün, Eberhard

    2008-09-01

    Galileo was the first articfiial satellite to orbit Jupiter. During its late orbital mission the spacecraft made two passages through the giant planet's gossamer ring system. The highly sensitive impact-ionization dust detector on board successfully recorded dust impacts during both ring passages and provided the first in-situ measurements from a dusty planetary ring. During the first passage { on 5 November 2002 while Galileo was approaching Jupiter - dust measurements were collected until a spacecraft anomaly at 2:33RJ (Jupiter radii) just 16 min after a close flyby of Amalthea put the spacecraft into a safing mode. The second ring passage on 21 September 2003 provided ring dust measurements down to about 2:5RJ and the Galileo spacecraft was destroyed shortly thereafter in a planned impact with Jupiter. In all, a few thousand dust impacts were counted with the instrument accumulators during both ring passages, but only a total of 110 complete data sets of dust impacts were transmitted to Earth (Krüger et al, Icarus, submitted). Detected particle sizes range from about 0.2 to 5 μm, extending the known size distribution by an order of magnitude towards smaller particles than previously derived from optical imaging (Showalter et al., Icarus 2008). The grain size distribution increases towards smaller particles and shows an excess of these tiny motes in the Amalthea gossamer ring compared to the Thebe ring. The size distribution for the Amalthea ring derived from our in-situ measurements for the small grains agrees very well with the one obtained from images for large grains. Our analysis shows that particles contributing most to the optical cross-section are approximately 5 μm in radius, in agreement with imaging results. The measurements indicate a large drop in particle ux immediately interior to Thebe's orbit and some detected particles seem to be on highly-tilted orbits with inclinations up to 20°. Finally, the faint Thebe ring extension was detected out to

  16. Development of micro-four-point probe in a scanning tunneling microscope for in situ electrical transport measurement

    SciTech Connect

    Ge, Jian-Feng; Liu, Zhi-Long; Gao, Chun-Lei; Qian, Dong; Liu, Canhua E-mail: jfjia@sjtu.edu.cn; Jia, Jin-Feng E-mail: jfjia@sjtu.edu.cn

    2015-05-15

    Electrons at surface may behave differently from those in bulk of a material. Multi-functional tools are essential in comprehensive studies on a crystal surface. Here, we developed an in situ microscopic four-point probe (4PP) transport measurement system on the basis of a scanning tunneling microscope (STM). In particular, convenient replacement between STM tips and micro-4PPs enables systematic investigations of surface morphology, electronic structure, and electrical transport property of a same sample surface. Performances of the instrument are demonstrated with high-quality STM images, tunneling spectra, and low-noise electrical I-V characteristic curves of a single-layer FeSe film grown on a conductive SrTiO{sub 3} surface.

  17. Quasi-reversible point defect relaxation in amorphous In-Ga-Zn-O thin films by in situ electrical measurements

    NASA Astrophysics Data System (ADS)

    Adler, Alexander U.; Yeh, Ted C.; Bruce Buchholz, D.; Chang, Robert P. H.; Mason, Thomas O.

    2013-03-01

    Quasi-reversible oxygen exchange/point defect relaxation in an amorphous In-Ga-Zn-O thin film was monitored by in situ electrical property measurements (conductivity, Seebeck coefficient) at 200 °C subjected to abrupt changes in oxygen partial pressure (pO2). By subtracting the long-term background decay from the conductivity curves, time-independent conductivity values were obtained at each pO2. From these values, a log-log "Brouwer" plot of conductivity vs. pO2 of approximately -1/2 was obtained, which may indicate co-elimination (filling) of neutral and charged oxygen vacancies. This work demonstrates that Brouwer analysis can be applied to the study of defect structure in amorphous oxide thin films.

  18. Lidar data inversion for Cirrus clouds: An approach based on a statistical analysis of in situ microphysical measurements

    SciTech Connect

    Febvre, G.

    1994-10-01

    The problem of the lidar equation inversion lies in the fact that it requires a lidar calibration or else a reference value from the studied medium. This paper presents an approach to calibrate the lidar by calculating the constant Ak (lidar constant A multiplied by the ratio of backscatter coefficient to extinction coefficient k). This approach is based on statistical analysis of in situ measurements. This analysis demonstrates that the extinction coefficient has a typical probablility distribution in cirrus clouds. The property of this distribution, as far as the attenuation of laser beam in the cloud, is used as a constraint to calculate the value of Ak. The validity of this method is discussed and results compared with two other inversion methods.

  19. Cooperative Mobile Sensing Systems for In Situ Measurements in Hazardous Environments

    NASA Astrophysics Data System (ADS)

    Argrow, B.

    2005-12-01

    Sondes are typically deployed from manned aircraft or taken to altitude by a balloon before they are dropped. There are obvious safety and physical limitations that dictate where and how sondes are deployed. These limitations have severely constrained sonde deployment into highly dynamic and dangerous environments. Additionally, conventional parachute dropsondes provide no means for active control. The "smartsonde" idea is to integrate miniature sonde packages into micro air vehicles (MAVs). These MAVs will be ferried into the hard to reach and hazardous environments to provide in situ measurements in regions that have been heretofore out of reach. Once deployed, the MAV will provide some means of control of the sonde, to enable it to remain aloft and to provide some measure of directional control. Preliminary smartsonde communications experiments have been completed. These experiments focused on characterizing the capabilities of the 802.11.4 wireless protocol. Range measurements with 60-mW, 2.4-GHz radios showed 100% throughput rate over 2.7 km during air to ground tests. The experiments also demonstrated the integration of an in-house distributed computing system that provides the interface between the sensors, UAV flight computers, and the telemetry system. The University of Colorado's Research and Engineering Center for Unmanned Vehicles (RECUV) is developing an engineering system that integrates small mobile sensor attributes into flexible mobile sensor infrastructures to be deployed for in situ sensing in hazardous environments. There are three focus applications: 1) Wildfire, to address sensing, communications, situational awareness, and safety needs to support fire-fighting operations and to increase capabilities for dynamic data acquisition for modeling and prediction; 2) Polar, where heterogeneous mixes of platforms and sensors will provide in-situ data acquisition from beneath the ocean surface into the troposphere; 3) Storm, to address the challenges

  20. In situ measurement of methane oxidation in groundwater by using natural-gradient tracer tests

    USGS Publications Warehouse

    Smith, R.L.; Howes, B.L.; Garabedian, S.P.

    1991-01-01

    Methane oxidation was measured in an unconfined sand and gravel aquifer (Cape Cod, Mass.) by using in situ natural-gradient tracer tests at both a pristine, oxygenated site and an anoxic, sewage-contaminated site. The tracer sites were equipped with multilevel sampling devices to create target grids of sampling points; the injectate was prepared with groundwater from the tracer site to maintain the same geochemical conditions. Methane oxidation was calculated from breakthrough curves of methane relative to halide and inert gas (hexafluoroethane) tracers and was confirmed by the appearance of 13C-enriched carbon dioxide in experiments in which 13C-enriched methane was used as the tracer. A V(max) for methane oxidation could be calculated when the methane concentration was sufficiently high to result in zero-order kinetics throughout the entire transport interval. Methane breakthrough curves could be simulated by modifying a one-dimensional advection-dispersion transport model to include a Michaelis-Menten-based consumption term for methane oxidation. The K(m) values for methane oxidation that gave the best match for the breakthrough curve peaks were 6.0 and 9.0 ??M for the uncontaminated and contaminated sites, respectively. Natural-gradient tracer tests are a promising approach for assessing microbial processes and for testing in situ bioremediation potential in groundwater systems.

  1. A rapid in situ respiration test for measuring aerobic biodegradation rates of hydrocarbons in soil.

    PubMed

    Hinchee, R E; Ong, S K

    1992-10-01

    An in situ test method to measure the aerobic biodegradation rates of hydrocarbons in contaminated soil is presented. The test method provides an initial assessment of bioventing as a remediation technology for hydrocarbon-contaminated soil. The in situ respiration test consists of ventilating the contaminated soil of the unsaturated zone with air and periodically monitoring the depletion of oxygen (O2) and production of carbon dioxide (CO2) over time after the air is turned off. The test is simple to implement and generally takes about four to five days to complete. The test was applied at eight hydrocarbon-contaminated sites of different geological and climatic conditions. These sites were contaminated with petroleum products or petroleum fuels, except for two sites where the contaminants were primarily polycyclic aromatic hydrocarbons. Oxygen utilization rates for the eight sites ranged from 0.02 to 0.99 percent O2/hour. Estimated biodegradation rates ranged from 0.4 to 19 mg/kg of soil/day. These rates were similar to the biodegradation rates obtained from field and pilot studies using mass balance methods. Estimated biodegradation rates based on O2 utilization were generally more reliable (especially for alkaline soils) than rates based on CO2 production. CO2 produced from microbial respiration was probably converted to carbonate under alkaline conditions.

  2. In situ measurement of methane oxidation in groundwater by using natural-gradient tracer tests.

    PubMed Central

    Smith, R L; Howes, B L; Garabedian, S P

    1991-01-01

    Methane oxidation was measured in an unconfined sand and gravel aquifer (Cape Cod, Mass.) by using in situ natural-gradient tracer tests at both a pristine, oxygenated site and an anoxic, sewage-contaminated site. The tracer sites were equipped with multilevel sampling devices to create target grids of sampling points; the injectate was prepared with groundwater from the tracer site to maintain the same geochemical conditions. Methane oxidation was calculated from breakthrough curves of methane relative to halide and inert gas (hexafluroethane) tracers and was confirmed by the appearance of 13C-enriched carbon dioxide in experiments in which 13C-enriched methane was used as the tracer. A Vmax for methane oxidation could be calculated when the methane concentration was sufficiently high to result in zero-order kinetics throughout the entire transport interval. Methane breakthrough curves could be simulated by modifying a one-dimensional adevection-dispersion transport model to include a Michaelis-Menten-based consumption term for methane oxidation. The Km values for methane oxidation that gave the best match for the breakthrough curve peaks were 6.0 and 9.0 microM for the uncontaminated and contaminated sites, respectively. Natural-gradient tracer tests are a promising approach for assessing microbial processes and for testing in situ bioremediation potential in groundwater systems. PMID:1892389

  3. Dissolved organic matter dynamics during storm events: combining in-situ and laboratory optical measurements to improve understanding

    NASA Astrophysics Data System (ADS)

    Khamis, Kieran; Bradley, Chris; Hannah, David; Stevens, Rob

    2015-04-01

    Despite the crucial role of dissolved organic matter (DOM) in catchment biogeochemistry; DOM fluxes from watersheds still remains poorly characterized. Recently, the mobilization and transport of DOM during storm events has received increased attention; with significant changes in DOM quality and quantity reported for forested and agricultural catchments. However, for urban systems, our understanding of the extent to which storms drive changes in DOM concentration and composition remains limited, particularly with regards to intra/inter-seasonal variability. In this study, we address this research gap by characterizing a number of storm events on a small urban stream (Bournbrook, Birmingham, U.K) during the winter and summer of 2014. An in-situ submersible fluorometer (Cyclops 7, Turner Inc.) was integrated with a traditional water quality sonde (Manta 2, Eureka) to obtain a continuous record of tryptophan-like fluorescence (TLF: BOD surrogate), turbidity, electrical conductivity (EC), water temperature (Tw) and stage. River water samples were collected using an automatic pump sampler at ≤ 1hr intervals and returned to the lab for a suite of analyses (total carbon quantification, absorbance and excitation emission spectrofluorometry). The flow regime was typical of an urban/suburban catchment with river stage extremely responsive to rainfall with lag times of <3 hrs. Both winter and summer storm events exhibited first flush responses with peak turbidity either on the rising limb or at peak discharge for all events (max. turbidity = 400NTU). Field and lab data highlighted systematic overestimation of in-situ TLF during base flow and high flow. Robust correction factors were developed and significantly improved the relationship between field and filtered lab measurements (R2> 0.8). The highest TLF values (in-situ and lab) were recorded during summer events, with corresponding winter events consistently displaying lower TLF concentrations. Antecedent hydro

  4. Polarized Imaging Nephelometer for in situ airborne measurements of aerosol light scattering.

    PubMed

    Dolgos, Gergely; Martins, J Vanderlei

    2014-09-01

    Global satellite remote sensing of aerosols requires in situ measurements to enable the calibration and validation of algorithms. In order to improve our understanding of light scattering by aerosol particles, and to enable routine in situ airborne measurements of aerosol light scattering, we have developed an instrument, called the Polarized Imaging Nephelometer (PI-Neph). We designed and built the PI-Neph at the Laboratory for Aerosols, Clouds and Optics (LACO) of the University of Maryland, Baltimore County (UMBC). This portable instrument directly measures the ambient scattering coefficient and phase matrix elements of aerosols, in the field or onboard an aircraft. The measured phase matrix elements are the P(11), phase function, and P(12). Lasers illuminate the sampled ambient air and aerosol, and a wide field of view camera detects scattered light in a scattering angle range of 3° to 176°. The PI-Neph measures an ensemble of particles, supplying the relevant quantity for satellite remote sensing, as opposed to particle-by-particle measurements that have other applications. Comparisons with remote sensing measurements will have to consider aircraft inlet effects. The PI-Neph first measured at a laser wavelength of 532nm, and was first deployed successfully in 2011 aboard the B200 aircraft of NASA Langley during the Development and Evaluation of satellite ValidatiOn Tools by Experimenters (DEVOTE) project. In 2013, we upgraded the PI-Neph to measure at 473nm, 532nm, and 671nm nearly simultaneously. LACO has deployed the PI-Neph on a number of airborne field campaigns aboard three different NASA aircraft. This paper describes the PI-Neph measurement approach and validation by comparing measurements of artificial spherical aerosols with Mie theory. We provide estimates of calibration uncertainties, which show agreement with the small residuals between measurements of P(11) and -P(12)/P(11) and Mie theory. We demonstrate the capability of the PI-Neph to measure

  5. Polarized Imaging Nephelometer for in situ airborne measurements of aerosol light scattering.

    PubMed

    Dolgos, Gergely; Martins, J Vanderlei

    2014-09-01

    Global satellite remote sensing of aerosols requires in situ measurements to enable the calibration and validation of algorithms. In order to improve our understanding of light scattering by aerosol particles, and to enable routine in situ airborne measurements of aerosol light scattering, we have developed an instrument, called the Polarized Imaging Nephelometer (PI-Neph). We designed and built the PI-Neph at the Laboratory for Aerosols, Clouds and Optics (LACO) of the University of Maryland, Baltimore County (UMBC). This portable instrument directly measures the ambient scattering coefficient and phase matrix elements of aerosols, in the field or onboard an aircraft. The measured phase matrix elements are the P(11), phase function, and P(12). Lasers illuminate the sampled ambient air and aerosol, and a wide field of view camera detects scattered light in a scattering angle range of 3° to 176°. The PI-Neph measures an ensemble of particles, supplying the relevant quantity for satellite remote sensing, as opposed to particle-by-particle measurements that have other applications. Comparisons with remote sensing measurements will have to consider aircraft inlet effects. The PI-Neph first measured at a laser wavelength of 532nm, and was first deployed successfully in 2011 aboard the B200 aircraft of NASA Langley during the Development and Evaluation of satellite ValidatiOn Tools by Experimenters (DEVOTE) project. In 2013, we upgraded the PI-Neph to measure at 473nm, 532nm, and 671nm nearly simultaneously. LACO has deployed the PI-Neph on a number of airborne field campaigns aboard three different NASA aircraft. This paper describes the PI-Neph measurement approach and validation by comparing measurements of artificial spherical aerosols with Mie theory. We provide estimates of calibration uncertainties, which show agreement with the small residuals between measurements of P(11) and -P(12)/P(11) and Mie theory. We demonstrate the capability of the PI-Neph to measure

  6. In Situ Measurements of Natural Radioactivity in Selected Igneous Rocks of the Opava Mountain Region

    NASA Astrophysics Data System (ADS)

    Dżaluk, Agnieszka; Malczewski, Dariusz; Żaba, Jerzy; Dziurowicz, Maria

    2014-09-01

    In situ gamma-ray measurements of four igneous rocks were taken in the Opava Mountains (Eastern Sudetes, Poland). The activity of naturally occurring radionuclides was measured using a portable GX3020 gamma-ray spectrometry workstation. The activity concentrations of 40K varied from 914 ± 17 Bqkg-1 (gneiss, Kamienna Góra) to 2019 ± 37 Bqkg-1 (weathered granite, Sławniowice), while those of 232Th from 7.5 ± 0.6 Bqkg-1 (weathered granite, Sławniowice) to 68 ± 0.9 Bqkg-1 (migmatitic gneiss, Nadziejów). The activities associated with 238U decay series ranged from 10 ± 0.4 Bqkg-1 (weathered granite, Sławniowice) to 62 ± 1.6 Bqkg-1 (gneiss, Kamienna Góra). The results will be used in compiling Radiological Atlas of the Sudetes

  7. Comparison of in situ stratospheric ozone measurements obtained during the MAP/GLOBUS 1983 campaign

    NASA Technical Reports Server (NTRS)

    Aimedieu, P.; Matthews, W. A.; Attmannspacher, W.; Hartmannsgruber, R.; Cisneros, J.; Komhyr, W.; Robbins, D. E.

    1987-01-01

    Data from five types of in situ ozone sensors flown aboard ballons during the MAP/GLOBUS 1983 campaign were found to agree to within 5 percent uncertainty throughout the middle atmosphere. A description of the individual techniques and the error budget is given in addition to explanations for the discrepancies found at higher and lower altitudes. In comparison to UV photometry values, results from two electrochemical techniques were found to be greater in the lower atmosphere and to be lower in the upper atmosphere. In general, olefin chemiluminescence results were within 8 percent of the UV photometry results. Ozone column contents measured by the indigo colorization technique for two altitude regions of about 6 km height were greater than measurements from other techniques by 52 and 17 percent, respectively.

  8. Chromosome translocations measured by fluorescence in-situ hybridization: A promising biomarker

    SciTech Connect

    Lucas, J.N.; Straume, T.

    1995-10-01

    A biomarker for exposure and risk assessment would be most useful if it employs an endpoint that is highly quantitative, is stable with time, and is relevant to human risk. Recent advances in chromosome staining using fluorescence in situ hybridization (FISH) facilitate fast and reliable measurement of reciprocal translocations, a kind of DNA damage linked to both prior exposure and risk. In contrast to other biomarkers available, the frequency of reciprocal translocations in individuals exposed to whole-body radiation is stable with time post exposure, has a rather small inter-individual variability, and can be measured accurately at the low levels. Here, the authors discuss results from their studies demonstrating that chromosome painting can be used to reconstruct radiation dose for workers exposed within the dose limits, for individuals exposed a long time ago, and even for those who have been diagnosed with leukemia but not yet undergone therapy.

  9. In Situ Frequency Measurement of Inidividual Nanostructures Using Fiber Optical Interferometry

    SciTech Connect

    Duden, Thomas; Duden, Thomas; Radmilovic, Velimir

    2008-07-01

    In this paper we describe a setup for the resonance frequency measurement of nanocantilevers, which displays both high spatial selectivity and sensitivity to specimen vibrations by utilizing a tapered uncoated fiber tip. The spatial selectivity is determined by the tip geometry, the high sensitivity to vibrations stems from interference of wave fronts reflected on the specimen and on the fiber tip itself. No reference plane on the specimen is needed, as demonstrated with the example of a freestanding silicon nitride cantilever. The resulting system is integrated in the DB-235 dual beam FIB system, thus allowing the measurement of sample responses in-situ, during observation in SEM mode. By combining optical interferometry and narrow band RF amplification and detection, we demonstrate an exceptional vibrational sensitivity at high spatial resolution.

  10. Porous silicon structural evolution from in-situ luminescence and Raman measurements

    SciTech Connect

    Tallant, D.R.; Kelly, M.J.; Guilinger, T.R.; Simpson, R.L.

    1996-05-01

    The authors performed in-situ photoluminescence and Raman measurements on an anodized silicon surface in the HF/ethanol solution used for anodization. The porous silicon thereby produced, while resident in HF/ethanol, does not immediately exhibit intense photoluminescence. Intense photoluminescence develops spontaneously in HF/ethanol after 18--24 hours or with replacement of the HF/ethanol with water. These results support a quantum confinement mechanism in which exciton migration to traps and nonradiative recombination dominates the de-excitation pathways until silicon nanocrystallites are physically separated and energetically decoupled by hydrofluoric acid etching or surface oxidation. The porous silicon surface, as produced by anodization, shows large differences in photoluminescence intensity and peak wavelength over millimeter distances. Parallel Raman measurements implicate nanometer-size silicon particles in the photoluminescence mechanism.

  11. In Situ Airborne Instrumentation: Addressing and Solving Measurement Problems in Ice Clouds

    SciTech Connect

    Baumgardner, Darrel; Kok, Greg; Avallone, L.; Bansemer, A.; Borrmann, S.; Brown, P.; Bundke, U.; Chuang, P. Y.; Cziczo, D.; Field, P.; Gallagher, M.; Gayet, J. -F.; Korolev, A.; Kraemer, M.; McFarquhar, G.; Mertes, S.; Moehler, O.; Lance, S.; Lawson, P.; Petters, M. D.; Pratt, K.; Roberts, G.; Rogers, D.; Stetzer, O.; Stith, J.; Strapp, W.; Twohy, C.; Wendisch, M.

    2012-02-01

    A meeting of 31 international experts on in situ measurements from aircraft was held to identify unresolved questions concerning ice formation and evolution in ice clouds, assess the current state of instrumentation that can address these problems, introduce emerging technology that may overcome current measurement issues and recommend future courses of action that can improve our understanding of ice cloud microphysical processes and their impact on the environment. The meeting proceedings and outcome has been described in detail in a manuscript submitted to the Bulletin of the American Meteorological Society (BAMS) on March 24, 2011. This paper is currently under review. The remainder of this summary, in the following pages, is the text of the BAMS article. A technical note that will be published by the National Center for Atmospheric Research is currently underway and is expected to be published before the end of the year.

  12. In Situ Airborne Instrumentation: Addressing and Solving Measurement Problems in Ice Clouds

    DOE PAGESBeta

    Baumgardner, Darrel; Kok, Greg; Avallone, L.; Bansemer, A.; Borrmann, S.; Brown, P.; Bundke, U.; Chuang, P. Y.; Cziczo, D.; Field, P.; et al

    2012-02-01

    A meeting of 31 international experts on in situ measurements from aircraft was held to identify unresolved questions concerning ice formation and evolution in ice clouds, assess the current state of instrumentation that can address these problems, introduce emerging technology that may overcome current measurement issues and recommend future courses of action that can improve our understanding of ice cloud microphysical processes and their impact on the environment. The meeting proceedings and outcome has been described in detail in a manuscript submitted to the Bulletin of the American Meteorological Society (BAMS) on March 24, 2011. This paper is currently undermore » review. The remainder of this summary, in the following pages, is the text of the BAMS article. A technical note that will be published by the National Center for Atmospheric Research is currently underway and is expected to be published before the end of the year.« less

  13. DOE capabilities for in-situ characterization and monitoring of formation properties in the vadose zone. Revision 2

    SciTech Connect

    Hearst, J.R.; Brodeur, J.R.; Koizumi, C.J.; Conaway, J.G.; Mikesell, J.L.; Nelson, P.H.; Stromswold, D.C.; Wilson, R.D.

    1993-09-01

    The DOE Environmental Restoration (ER) Program faces the difficult task of characterizing the properties of the subsurface and identifying and mapping a large number of contaminants at landfills, surface disposal areas, spill sites, nuclear waste tanks, and subsurface contaminant plumes throughout the complex of DOE facilities. Geophysical borehole logs can measure formation properties such as bulk density, water content, and lithology, and can quantitatively analyze for radionuclides and such elements as chlorine and heavy metals. Since these measurements can be repeated as desired, they can be used for both initial characterization and monitoring of changes in contaminant concentration and water content (sometimes linked to contaminant migration), at a fraction of the cost of conventional sampling. The techniques developed at several DOE laboratories, and the experience that we have gained in making in-situ measurements in the vadose zone, are applicable to problems at many other DOE sites. Moreover, they can capitalize on existing inventories of boreholes. By building on this experience workers involved in ER projects at those sites should be able to obtain high-quality data at substantial reductions in cost and time.

  14. In Situ Thermal Ion Temperature Measurements in the E Region Ionosphere: Techniques, Results, and Limitations

    NASA Astrophysics Data System (ADS)

    Burchill, J. K.; Archer, W. E.; Clemmons, J. H.; Knudsen, D. J.; Nicolls, M. J.

    2011-12-01

    In situ measurements of thermal ion temperature are rare at E region altitudes, which are too low for satellites. Here we present ion temperature measurements from a Thermal Ion Imager (TII) that flew on NASA sounding rocket 36.234 (the "Joule-2" mission) into the nightside E region ionosphere on 19 January 2007 from Poker Flat, AK. The TII is an electrostatic ion energy/angle imager that provides 2D ion distributions at 8 ms resolution. Ion temperatures are derived at altitudes between 100 km and 190 km by modelling the detector total count rate versus ion bulk flow angle with respect to the plane of the imager's field of view. Modelling this count rate spin profile shows that the analysis technique is robust against a number of error sources, including variability in payload floating potential, ion upflow, and aperture widening due to reflections from electrode surfaces. A significant uncertainty is associated with the average mass of the ions, which is not measured independently. Using the International Reference Ionosphere model to estimate ion mass, we obtain an ion temperature of 1300 K at 125 km, increasing to more than 3000 K at 180 km. These temperatures are much larger than neutral temperatures obtained from an ionization gauge on the same rocket (Tn˜500 K at 125 km, ˜600 K at 180 km), and do not agree with incoherent scatter radar observations in the vicinity of the rocket. These anomalous ion temperatures are, however, consistent with results from an independent analysis of the shape of the ion distribution images from a similar instrument on a separate payload flown 10 minutes earlier [Archer, MSc Thesis, University of Calgary, 2009]. We conclude that the high ion temperature readings are an artifact related to the environment in the vicinity of the probe, and investigate mechanisms for the cause. We discuss the implications of this effect for future in situ attempts to measure ion temperature in the E region ionosphere.

  15. Comparison of in-situ measurements and satellite-derived surface emissivity over Italian volcanic areas

    NASA Astrophysics Data System (ADS)

    Silvestri, Malvina; Musacchio, Massimo; Cammarano, Diego; Fabrizia Buongiorno, Maria; Amici, Stefania; Piscini, Alessandro

    2016-04-01

    In this work we compare ground measurements of emissivity collected during dedicated fields campaign on Mt. Etna and Solfatara of Pozzuoli volcanoes and acquired by means of Micro-FTIR (Fourier Thermal Infrared spectrometer) instrument with the emissivity obtained by using single ASTER data (Advanced Spaceborne Thermal Emission and Reflection Radiometer, ASTER 05) and the ASTER emissivity map extract from ASTER Global Emissivity Database (GED), released by LP DAAC on April 2, 2014. The database was developed by the National Aeronautics and Space Administration's (NASA) Jet Propulsion Laboratory (JPL), California Institute of Technology. The database includes land surface emissivity derived from ASTER data acquired over the contiguous United States, Africa, Arabian Peninsula, Australia, Europe, and China. Through this analysis we want to investigate the differences existing between the ASTER-GED dataset (average from 2000 to 2008 seasoning independent) and fall in-situ emissivity measurement. Moreover the role of different spatial resolution characterizing ASTER and MODIS, 90mt and 1km respectively, by comparing them with in situ measurements, is analyzed. Possible differences can be due also to the different algorithms used for the emissivity estimation, Temperature and Emissivity Separation algorithm for ASTER TIR band( Gillespie et al, 1998) and the classification-based emissivity method (Snyder and al, 1998) for MODIS. Finally land surface temperature products generated using ASTER-GED and ASTER 05 emissivity are also analyzed. Gillespie, A. R., Matsunaga, T., Rokugawa, S., & Hook, S. J. (1998). Temperature and emissivity separation from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images. IEEE Transactions on Geoscience and Remote Sensing, 36, 1113-1125. Snyder, W.C., Wan, Z., Zhang, Y., & Feng, Y.-Z. (1998). Classification-based emissivity for land surface temperature measurement from space. International Journal of Remote Sensing, 19

  16. Mars dayside temperature from airglow limb profiles : comparison with in situ measurements and models

    NASA Astrophysics Data System (ADS)

    Gérard, Jean-Claude; Bougher, Stephen; Montmessin, Franck; Bertaux, Jean-Loup; Stiepen, A.

    The thermal structure of the Mars upper atmosphere is the result of the thermal balance between heating by EUV solar radiation, infrared heating and cooling, conduction and dynamic influences such as gravity waves, planetary waves, and tides. It has been derived from observations performed from different spacecraft. These include in situ measurements of orbital drag whose strength depends on the local gas density. Atmospheric temperatures were determined from the altitude variation of the density measured in situ by the Viking landers and orbital drag measurements. Another method is based on remote sensing measurements of ultraviolet airglow limb profiles obtained over 40 years ago with spectrometers during the Mariner 6 and 7 flybys and from the Mariner 9 orbiter. Comparisons with model calculations indicate that they both reflect the CO_2 scale height from which atmospheric temperatures have been deduced. Upper atmospheric temperatures varying over the wide range 270-445 K, with a mean value of 325 K were deduced from the topside scale height of the airglow vertical profile. We present an analysis of limb profiles of the CO Cameron (a(3) Pi-X(1) Sigma(+) ) and CO_2(+) doublet (B(2) Sigma_u(+) - X(2) PiΠ_g) airglows observed with the SPICAM instrument on board Mars Express. We show that the temperature in the Mars thermosphere is very variable with a mean value of 270 K, but values ranging between 150 and 400 K have been observed. These values are compared to earlier determinations and model predictions. No clear dependence on solar zenith angle, latitude or season is apparent. Similarly, exospheric variations with F10.7 in the SPICAM airglow dataset are small over the solar minimum to moderate conditions sampled by Mars Express since 2005. We conclude that an unidentified process is the cause of the large observed temperature variability, which dominates the other sources of temperature variations.

  17. Evapotranspiration partitioning through in-situ oxygen isotope measurements in an oasis cropland

    NASA Astrophysics Data System (ADS)

    Wen, Xue-Fa

    2016-04-01

    The oxygen isotope compositions of ecosystem water pools and fluxes are useful tracers in the water cycle. As part of the Heihe Watershed Allied Telemetry Experimental Research (HiWATER) program, high-frequency and near-continuous in situ measurements of 18O composition of atmospheric vapor (δv) and of evapotranspiration (δET) were made with the flux-gradient method using a cavity ring-down spectroscopy water vapor isotope analyzer. At the sub-daily scale, we found, in conjunction with intensive isotopic measurements of other ecosystem water pools, that the differences between 18O composition of transpiration (δT) and of xylem water (δx) were negligible in early afternoon (13:00-15:00 Beijing time) when ET approached the daytime maximum, indicating isotopic steady state. At the daily scale, for the purpose of flux partitioning, δT was approximated by δx at early afternoon hours, and the 18O composition of soil evaporation (δE) was obtained from the Craig-Gordon model with a moisture-dependent soil resistance. The relative contribution of transpiration to evapotranspiration ranged from 0.71 to 0.96 with a mean of 0.87 ± 0.052 for the growing season according to the isotopic labeling, which was good agreement with soil lysimeter measurements showing a mean transpiration fraction of 0.86 ± 0.058. At the growing season scale, the predicted18O composition of runoff water was within the range of precipitation and irrigation water according to the isotopic mass conservation. The 18O mass conservation requires that the decreased δ18O of ET should be balanced by enhanced δ18O of runoff water. (Wen, XF*, Yang, B, Sun, XM, Lee, X. 2015. Evapotranspiration partitioning through in-situ oxygen isotope measurements in an oasis cropland. Agricultural and Forest Meteorology , doi:10.1016/j.agrformet.2015.12.003).

  18. In Situ Water Vapor and Ozone Measurements in Lhasa and Kunming during the Asian Summer Monsoon

    NASA Astrophysics Data System (ADS)

    Pan, L.; Bian, J.; Paulik, L.; Voemel, H.; Lu, D.; Chen, H.

    2012-12-01

    The Asian summer monsoon (ASM) anticyclone circulation system is recognized to be a significant transport pathway for water vapor and pollutants to enter the stratosphere. The observational evidence, however, is largely based on satellite retrievals. We report the first coincident in situ measurements of water vapor and ozone within the ASM anticyclone. The combined water vapor and ozonesondes were launched from Kunming, China in August 2009 and Lhasa, China in August 2010. Total of 11 and 12 sondes were launched in Kunming and Lhasa, respectively. We present the key characteristics of these measurements, and provide a comparison to similar measurements from Alajuela, Costa Rica, an equatorial tropical location, during the Tropical Composition, Cloud and Climate Coupling (TC4) campaign in July and August of 2007. Results show that the ASM anticyclone region has higher water vapor and lower ozone concentrations in the upper troposphere and lower stratosphere than the TC4 observations. The results also show that the cold point tropopause in the ASM region has a higher average height and potential temperature. The in situ observations therefore support the satellite-based conclusions that the ASM is an effective transport pathway for water vapor to enter stratosphere. The data also show that the vertical structures of the region in and around the anticyclone are different: while the estimated level of main convective outflow is higher in Lhasa (~13 km, or 358 K) than in Kunming (~11.5 km, 354 K), the Kunming measurements, owing to its position of near the edge of the anticyclone, show influence of extreme convective events in air masses transported from remote western Pacific.

  19. Comparison of in-situ measurements and satellite-derived surface emissivity over Italian volcanic areas

    NASA Astrophysics Data System (ADS)

    Silvestri, Malvina; Musacchio, Massimo; Cammarano, Diego; Fabrizia Buongiorno, Maria; Amici, Stefania; Piscini, Alessandro

    2016-04-01

    In this work we compare ground measurements of emissivity collected during dedicated fields campaign on Mt. Etna and Solfatara of Pozzuoli volcanoes and acquired by means of Micro-FTIR (Fourier Thermal Infrared spectrometer) instrument with the emissivity obtained by using single ASTER data (Advanced Spaceborne Thermal Emission and Reflection Radiometer, ASTER 05) and the ASTER emissivity map extract from ASTER Global Emissivity Database (GED), released by LP DAAC on April 2, 2014. The database was developed by the National Aeronautics and Space Administration's (NASA) Jet Propulsion Laboratory (JPL), California Institute of Technology. The database includes land surface emissivity derived from ASTER data acquired over the contiguous United States, Africa, Arabian Peninsula, Australia, Europe, and China. Through this analysis we want to investigate the differences existing between the ASTER-GED dataset (average from 2000 to 2008 seasoning independent) and fall in-situ emissivity measurement. Moreover the role of different spatial resolution characterizing ASTER and MODIS, 90mt and 1km respectively, by comparing them with in situ measurements, is analyzed. Possible differences can be due also to the different algorithms used for the emissivity estimation, Temperature and Emissivity Separation algorithm for ASTER TIR band( Gillespie et al, 1998) and the classification-based emissivity method (Snyder and al, 1998) for MODIS. Finally land surface temperature products generated using ASTER-GED and ASTER 05 emissivity are also analyzed. Gillespie, A. R., Matsunaga, T., Rokugawa, S., & Hook, S. J. (1998). Temperature and emissivity separation from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images. IEEE Transactions on Geoscience and Remote Sensing, 36, 1113‑1125. Snyder, W.C., Wan, Z., Zhang, Y., & Feng, Y.-Z. (1998). Classification-based emissivity for land surface temperature measurement from space. International Journal of Remote Sensing

  20. In situ synthesis of CuO and Cu nanostructures with promising electrochemical and wettability properties.

    PubMed

    Zhang, Qiaobao; Xu, Daguo; Zhou, Xiang; Wu, Xianwen; Zhang, Kaili

    2014-03-12

    A strategy is presented for the in situ synthesis of single crystalline CuO nanorods and 3D CuO nanostructures, ultra-long Cu nanowires and Cu nanoparticles at relatively low temperature onto various substrates (Si, SiO2 , ITO, FTO, porous nickel, carbon cotton, etc.) by one-step thermal heating of copper foam in static air and inert gas, respectively. The density, particle sizes and morphologies of the synthesized nanostructures can be effectively controlled by simply tailoring the experimental parameters. A compressive stress based and subsequent structural rearrangements mechanism is proposed to explain the formation of the nanostructures. The as-prepared CuO nanostructures demonstrate promising electrochemical properties as the anode materials in lithium-ion batteries and also reversible wettability. Moreover, this strategy can be used to conveniently integrate these nanostructures with other nanostructures (ZnO nanorods, Co3 O4 nanowires and nanowalls, TiO2 nanotubes, and Si nanowires) to achieve various hybrid hierarchical (CuO-ZnO, CuO-Co3 O4 , CuO-TiO2 , CuO-Si) nanocomposites with promising properties. This strategy has the potential to provide the nano society with a general way to achieve a variety of nanostructures. PMID:24174010

  1. Synthesis and physicochemical properties of epoxidized Tmp trioleate by in situ method

    SciTech Connect

    Samidin, Salma; Salimon, Jumat

    2014-09-03

    Tmp trioleate was initially synthesized via esterification of trimetilolprapane and oleic acid (90%) using 1.5% of H{sub 2}SO{sub 4} as a catalyst. The production of Tmp trioleate was observed at 98% (w/w). The iodine value of Tmp trioleate was analyzed for further reaction of epoxidation. Epoxide was important reaction as an intermediate for preparation of chemical modified lubricants from vegetable oils. Finding the best way of epoxidation process will give high quality for further modification of oil instead of reduce the cost and time for the preparation process during reaction of epoxidation. In this study, the epoxidation of unsaturation Tmp trioleate with peroxyformic acid generated in-situ from hydrogen peroxide 30% in H{sub 2}O{sub 2} with formic acid was studied. 95% conversion to oxygen oxirane content (OOC) ring was obtained. The derivatization showed an improvement of the compound's oxidative stability evidenced from pressurized differential scanning calorimetry (PDSC) data which are 177°C to 200°C. Physicochemical properties showed increasing of temperature of flash point from 280°C to 300°C and viscosity index (VI) from 146 to 154. However, the pour point showed increasing temperature which was −58.81°C to −17.32°C. From the data obtained, these derivatives have shown better performance of lubricity properties. Overall, the data indicates that these performances are compatible to the commercial lubricants.

  2. Synthesis and physicochemical properties of epoxidized Tmp trioleate by in situ method

    NASA Astrophysics Data System (ADS)

    Samidin, Salma; Salimon, Jumat

    2014-09-01

    Tmp trioleate was initially synthesized via esterification of trimetilolprapane and oleic acid (90%) using 1.5% of H2SO4 as a catalyst. The production of Tmp trioleate was observed at 98% (w/w). The iodine value of Tmp trioleate was analyzed for further reaction of epoxidation. Epoxide was important reaction as an intermediate for preparation of chemical modified lubricants from vegetable oils. Finding the best way of epoxidation process will give high quality for further modification of oil instead of reduce the cost and time for the preparation process during reaction of epoxidation. In this study, the epoxidation of unsaturation Tmp trioleate with peroxyformic acid generated in-situ from hydrogen peroxide 30% in H2O2 with formic acid was studied. 95% conversion to oxygen oxirane content (OOC) ring was obtained. The derivatization showed an improvement of the compound's oxidative stability evidenced from pressurized differential scanning calorimetry (PDSC) data which are 177°C to 200°C. Physicochemical properties showed increasing of temperature of flash point from 280°C to 300°C and viscosity index (VI) from 146 to 154. However, the pour point showed increasing temperature which was -58.81°C to -17.32°C. From the data obtained, these derivatives have shown better performance of lubricity properties. Overall, the data indicates that these performances are compatible to the commercial lubricants.

  3. In situ synthesis of CuO and Cu nanostructures with promising electrochemical and wettability properties.

    PubMed

    Zhang, Qiaobao; Xu, Daguo; Zhou, Xiang; Wu, Xianwen; Zhang, Kaili

    2014-03-12

    A strategy is presented for the in situ synthesis of single crystalline CuO nanorods and 3D CuO nanostructures, ultra-long Cu nanowires and Cu nanoparticles at relatively low temperature onto various substrates (Si, SiO2 , ITO, FTO, porous nickel, carbon cotton, etc.) by one-step thermal heating of copper foam in static air and inert gas, respectively. The density, particle sizes and morphologies of the synthesized nanostructures can be effectively controlled by simply tailoring the experimental parameters. A compressive stress based and subsequent structural rearrangements mechanism is proposed to explain the formation of the nanostructures. The as-prepared CuO nanostructures demonstrate promising electrochemical properties as the anode materials in lithium-ion batteries and also reversible wettability. Moreover, this strategy can be used to conveniently integrate these nanostructures with other nanostructures (ZnO nanorods, Co3 O4 nanowires and nanowalls, TiO2 nanotubes, and Si nanowires) to achieve various hybrid hierarchical (CuO-ZnO, CuO-Co3 O4 , CuO-TiO2 , CuO-Si) nanocomposites with promising properties. This strategy has the potential to provide the nano society with a general way to achieve a variety of nanostructures.

  4. Improved Beam Diagnostic Spatial Calibration Using In-Situ Measurements of Beam Emission

    NASA Astrophysics Data System (ADS)

    Chrystal, C.; Burrell, K. H.; Pace, D. C.; Grierson, B. A.; Pablant, N. A.

    2014-10-01

    A new technique has been developed for determining the measurement geometry of the charge exchange recombination spectroscopy diagnostic (CER) on DIII-D. This technique removes uncertainty in the measurement geometry related to the position of the neutral beams when they are injecting power. This has been accomplished by combining standard measurements that use in-vessel calibration targets with spectroscopic measurements of Doppler shifted and Stark split beam emission to fully describe the neutral beam positions and CER views. A least squares fitting routine determines the measurement geometry consistent with all the calibration data. The use of beam emission measurements allows the position of the neutral beams to be determined in-situ by the same views that makeup the CER diagnostic. Results indicate that changes in the measurement geometry are required to create a consistent set of calibration measurements. However, changes in quantities derived from the geometry, e.g. ion temperature gradient and poloidal rotation, are small. Work supported by the US DOE under DE-FG02-07ER54917, DE-FC02-04ER54698, and DE-AC02-09H11466.

  5. In situ measurements of the oblique incidence sound absorption coefficient for finite sized absorbers.

    PubMed

    Ottink, Marco; Brunskog, Jonas; Jeong, Cheol-Ho; Fernandez-Grande, Efren; Trojgaard, Per; Tiana-Roig, Elisabet

    2016-01-01

    Absorption coefficients are mostly measured in reverberation rooms or with impedance tubes. Since these methods are only suitable for measuring the random incidence and the normal incidence absorption coefficient, there exists an increasing need for absorption coefficient measurement of finite absorbers at oblique incidence in situ. Due to the edge diffraction effect, oblique incidence methods considering an infinite sample fail to measure the absorption coefficient at large incidence angles of finite samples. This paper aims for the development of a measurement method that accounts for the finiteness of the absorber. A sound field model, which accounts for scattering from the finite absorber edges, assuming plane wave incidence is derived. A significant influence of the finiteness on the radiation impedance and the corresponding absorption coefficient is found. A finite surface method, which combines microphone array measurements over a finite sample with the sound field model in an inverse manner, is proposed. Besides, a temporal subtraction method, a microphone array method, impedance tube measurements, and an equivalent fluid model are used for validation. The finite surface method gives promising agreement with theory, especially at near grazing incidence. Thus, the finite surface method is proposed for further measurements at large incidence angles. PMID:26827003

  6. Quantitatively Measuring In situ Flows using a Self-Contained Underwater Velocimetry Apparatus (SCUVA)

    PubMed Central

    Katija, Kakani; Colin, Sean P.; Costello, John H.; Dabiri, John O.

    2011-01-01

    The ability to directly measure velocity fields in a fluid environment is necessary to provide empirical data for studies in fields as diverse as oceanography, ecology, biology, and fluid mechanics. Field measurements introduce practical challenges such as environmental conditions, animal availability, and the need for field-compatible measurement techniques. To avoid these challenges, scientists typically use controlled laboratory environments to study animal-fluid interactions. However, it is reasonable to question whether one can extrapolate natural behavior (i.e., that which occurs in the field) from laboratory measurements. Therefore, in situ quantitative flow measurements are needed to accurately describe animal swimming in their natural environment. We designed a self-contained, portable device that operates independent of any connection to the surface, and can provide quantitative measurements of the flow field surrounding an animal. This apparatus, a self-contained underwater velocimetry apparatus (SCUVA), can be operated by a single scuba diver in depths up to 40 m. Due to the added complexity inherent of field conditions, additional considerations and preparation are required when compared to laboratory measurements. These considerations include, but are not limited to, operator motion, predicting position of swimming targets, available natural suspended particulate, and orientation of SCUVA relative to the flow of interest. The following protocol is intended to address these common field challenges and to maximize measurement success. PMID:22064442

  7. Diel Variability in Dissolved Organic Matter Composition Determined by in-situ Optical Measurements.

    NASA Astrophysics Data System (ADS)

    Spencer, R. G.; Pellerin, B. A.; Bergamaschi, B. A.; Downing, B. D.; Kraus, T. E.; Hernes, P. J.

    2006-12-01

    Annual and interannual variability in DOM concentration and composition in rivers has been well documented however few studies have evaluated changes in DOM over short time scales such as diel cycles. Recent research has shown that concentrations of dissolved oxygen, inorganic nitrogen and trace metals for example vary considerably over diel cycles in streams and rivers due to a combination of biological, physical and chemical processes. In this study DOM variability was investigated over the diel cycle under stable riverine summer flow conditions in the San Joaquin River (California, U.S.A.) to evaluate if high resolution in-situ optical measurements revealed changes in DOM concentration and composition. Bulk dissolved organic carbon (DOC) concentrations showed no clear trend over diel cycles but in contrast the absorption coefficient of chromophoric DOM (CDOM) measured in situ at 350nm (a350 m-1 showed a clear diurnal pattern with CDOM maxima in the late evening and minima in the early morning. Similar diurnal patterns were recorded at a254 m- 1 and a440 m-1, absorbance wavelengths which have also been referred too as proxies for DOC quality and quantity. Chlorophyll-a fluorescence showed the same diurnal pattern as CDOM absorbance with early evening maxima and early morning minima in concentrations and previous studies indicate that phytoplankton is the primary source of organic matter in the San Joaquin River during summer months. In situ DOM fluorescence (measured at excitiation 370 nm, emission 450 nm) and spectral slope (S) calculated using a non-linear fit of an exponential function to the absorption spectrum in the range of 290 - 350 nm both showed clear diurnal patterns. With respect to DOM fluorescence and S290-350 maxima were recorded in the morning and minima in the late evening and so were out of phase with CDOM absorbance and chlorophyll-a fluorescence. This asynchronous pattern in DOM fluorescence and absorption coefficients over diel cycles in our

  8. Estimation of inherent optical properties using in situ hyperspectral radiometer and MODIS data along the east coast of New Caledonia

    NASA Astrophysics Data System (ADS)

    Murakami, Hiroshi; Dupouy, Cécile; Röttgers, Rüdiger; Frouin, Robert J.

    2012-10-01

    Hyperspectral remote sensing reflectance (Rrs) was measured by a TriOS radiometer system along the East Coast of New Caledonia during the R/V Alis 03-13 October 2011 CALIOPE cruise. The TriOS system consists of radiance and irradiance sensors measuring in the spectral range 320-950 nm, at a spectral resolution of about 10 nm (sampled by every 3.3 nm), and within a 7-degree field-of-view for the radiance sensor. The method developed by Froidefond and Ouillon (2005) was used to determine Rrs, i.e., the radiance sensor was mounted on a small raft to measure upwelling radiance just below the surface, and Rrs was calculated by normalizing water-leaving radiance with downward solar irradiance measured on the ship deck. Inherent Optical Properties (IOPs), i.e., absorption coefficients of phytoplankton and detritus+dissolved substances (aph and adg, respectively), and particulate backscattering coefficient (bbp) were estimated from the hyperspectral Rrs data by applying linear matrix inversion (Hoge and Lyon, 1996). The IOP inversion algorithm was adapted to MODIS data and applied to Level 1b imagery at 500 m resolution to demonstrate the feasibility of regular IOP monitoring from space in the study area. Local characteristics of the IOP spectra were used for the candidate spectra in the algorithm. The estimated MODIS Rrs and IOPs were evaluated using TriOS Rrs and in-situ IOP measurements obtained concomitantly during the cruise.

  9. Using STOQS and stoqstoolbox for in situ Measurement Data Access in Matlab

    NASA Astrophysics Data System (ADS)

    López-Castejón, F.; Schlining, B.; McCann, M. P.

    2012-12-01

    This poster presents the stoqstoolbox, an extension to Matlab that simplifies the loading of in situ measurement data directly from STOQS databases. STOQS (Spatial Temporal Oceanographic Query System) is a geospatial database tool designed to provide efficient access to data following the CF-NetCDF Discrete Samples Geometries convention. Data are loaded from CF-NetCDF files into a STOQS database where indexes are created on depth, spatial coordinates and other parameters, e.g. platform type. STOQS provides consistent, simple and efficient methods to query for data. For example, we can request all measurements with a standard_name of sea_water_temperature between two times and from between two depths. Data access is simpler because the data are retrieved by parameter irrespective of platform or mission file names. Access is more efficient because data are retrieved via the index on depth and only the requested data are retrieved from the database and transferred into the Matlab workspace. Applications in the stoqstoolbox query the STOQS database via an HTTP REST application programming interface; they follow the Data Access Object pattern, enabling highly customizable query construction. Data are loaded into Matlab structures that clearly indicate latitude, longitude, depth, measurement data value, and platform name. The stoqstoolbox is designed to be used in concert with other tools, such as nctoolbox, which can load data from any OPeNDAP data source. With these two toolboxes a user can easily work with in situ and other gridded data, such as from numerical models and remote sensing platforms. In order to show the capability of stoqstoolbox we will show an example of model validation using data collected during the May-June 2012 field experiment conducted by the Monterey Bay Aquarium Research Institute (MBARI) in Monterey Bay, California. The data are available from the STOQS server at http://odss.mbari.org/canon/stoqs_may2012/query/. Over 14 million data points of

  10. Mercury dynamics in a San Francisco estuary tidal wetland: assessing dynamics using in situ measurements

    USGS Publications Warehouse

    Bergamaschi, Brian A.; Fleck, Jacob A.; Downing, Bryan D.; Boss, Emmanuel; Pellerin, Brian A.; Ganju, Neil K.; Schoellhamer, David H.; Byington, Amy A.; Heim, Wesley A.; Stephenson, Mark; Fujii, Roger

    2012-01-01

    We used high-resolution in situ measurements of turbidity and fluorescent dissolved organic matter (FDOM) to quantitatively estimate the tidally driven exchange of mercury (Hg) between the waters of the San Francisco estuary and Browns Island, a tidal wetland. Turbidity and FDOM—representative of particle-associated and filter-passing Hg, respectively—together predicted 94 % of the observed variability in measured total mercury concentration in unfiltered water samples (UTHg) collected during a single tidal cycle in spring, fall, and winter, 2005–2006. Continuous in situ turbidity and FDOM data spanning at least a full spring-neap period were used to generate UTHg concentration time series using this relationship, and then combined with water discharge measurements to calculate Hg fluxes in each season. Wetlands are generally considered to be sinks for sediment and associated mercury. However, during the three periods of monitoring, Browns Island wetland did not appreciably accumulate Hg. Instead, gradual tidally driven export of UTHg from the wetland offset the large episodic on-island fluxes associated with high wind events. Exports were highest during large spring tides, when ebbing waters relatively enriched in FDOM, dissolved organic carbon (DOC), and filter-passing mercury drained from the marsh into the open waters of the estuary. On-island flux of UTHg, which was largely particle-associated, was highest during strong winds coincident with flood tides. Our results demonstrate that processes driving UTHg fluxes in tidal wetlands encompass both the dissolved and particulate phases and multiple timescales, necessitating longer term monitoring to adequately quantify fluxes.

  11. Water quality monitoring of Al-Habbaniyah Lake using remote sensing and in situ measurements.

    PubMed

    Al-Fahdawi, Ahmed A H; Rabee, Adel M; Al-Hirmizy, Shaheen M

    2015-06-01

    The use of remote sensing and GIS in water monitoring and management has been long recognized. This paper, however discusses the application of remote sensing and GIS specifically in monitoring water quality parameters in Al-Habbaniyah Lake, and the results were compared with in situ measurements. Variations of different parameters under investigation were as follows: temperature (15-33°C), pH (7-9), dissolved oxygen (6-11 mg/L), BOD5 (0.5-1.8), electrical conductivity (200-2280 μS/cm), TDS (147-1520 mg/L), TSS (68-3200), turbidity (5-51), nitrate (0.7-20 mg/l), phosphate (77-220 μg/l), and chlorophyll-a (0.9-130 μg/l). Remote sensing results revealed that the band 5 was most likely significantly correlated with turbidity in the winter. Band 2 and 3 was most likely significantly correlated with TDS in autumn and summer, while band 2 was most likely significantly correlated with TSS in autumn, band 2 is most likely significantly correlated with chlorophyll-a in autumn. The current study results demonstrated convergence between in situ and remote sensing readings. The models were used to explore the values of each of chlorophyll-a, TSS,TDS, and turbidity did not deviate much from the values actually measured in the three seasons. Nevertheless, they were very useful in anticipating all seasons of the study due to the insignificant deviation between the remotely sensed values and actual measured values.

  12. Galileo In-Situ Dust Measurements and the Physics of Jupiter's Gossamer Rings

    NASA Astrophysics Data System (ADS)

    Krueger, H.; Hamilton, D. P.; Moissl, R.; Gruen, E.

    2007-12-01

    During its late orbital mission about Jupiter, the Galileo spacecraft flew twice through the giant planet's gossamer ring system. The dusty ring material is produced when interplanetary impactors collide with embedded moonlets. Optical images imply that the rings are constrained both horizontally and vertically by the orbits of the moons Amalthea and Thebe with the exception of a faint outward protrusion called the Thebe Extension. During the ring passages, the Galileo impact-ionization dust detector counted a few thousand impacts but only about 100 complete data sets of dust impacts (i.e. impact time, impact speed, mass, impact direction, etc.) were successfully transmitted to Earth. The instrument verified the outward extension of the gossamer ring beyond Thebe's orbit and measured a major reduction in particle ring material interior to Thebe's orbit. The existence of this partially evacuated gap in ring material is also indirectly confirmed by Galileo in-situ energetic particle measurements (Norbert Krupp, priv. comm.). Detected particle sizes range from about 0.2 to 4 micron, extending the size distribution by an order of magnitude towards smaller particles than previously derived from optical imaging (Showalter et al., Icarus 2007). The grain size distribution increases towards smaller grains, showing a much higher proportion of small particles in the Amalthea gossamer ring than in the Thebe ring and the Thebe Extension. Our analysis shows that particles contributing most to the optical cross-section are about 4 micron in radius, in agreement with imaging results. Finally, Galileo also detected some micron and sub-micron grains on highly inclined orbits with inclinations up to 20 degrees. Recent modelling (Hamilton & Krueger, Nature, submitted) shows that time variable electromagnetic effects can account for all of these surprising results. In particular, when the ring particles travel through Jupiter's shadow, dust grain electric charges vary systematically

  13. A miniature all-solid-state calcium electrode applied to in situ seawater measurement

    NASA Astrophysics Data System (ADS)

    Xu, Hui; Wang, You; Luo, Zhiyuan; Pan, Yiwen

    2013-12-01

    An all-solid-state miniature calcium ion selective electrode (ISE) based on poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT(PSS)) for continuous in situ measurement in seawater was studied. The electrode substrate was a platinum (Pt) wire of 0.5 mm diameter and PEDOT(PSS) was electropolymerized on one end of the Pt wire to act as the solid contact of this calcium ISE. The PEDOT(PSS) layer was covered with a calcium-selective poly(vinyl chloride) membrane, which contained ETH129 as calcium ionophore, potassium tetrakis-(p-chlorophenyl)borate as lipophilic anion and bis(2-ethylhexyl) sebacate as the plasticizer. Experiments using electrochemical impedance spectroscopy and reversed chronopotentiometry illustrated that electropolymerized PEDOT(PSS) decreased the resistance and improved the stability of the electrode. The sensors can work stably in the calcium ion concentration range of 10-6-10-1 mol L-1 with the slope of 27.7 mV/decade. Also Na+, K+ and Mg2+ can hardly interfere with the performance of the electrode. This electrode was applied to measure the calcium ion concentration of seawater samples. The experimental data showed that the electrode can resist the corrosion of seawater and its reproducibility was good (SD < 0.1 mM kg-1). The lifetime of such an electrode was at least six months. Because of the wire-shape and the small size of such a liquid junction free calcium electrode, it is pressure-resistant and easy to package and seal, therefore it is suitable for use in underwater equipment for in situ seawater measurement.

  14. Southern Ocean variability derived from GRACE retrievals, model simulations and in-situ measurements

    NASA Astrophysics Data System (ADS)

    Böning, C.; Timmermann, R.; Macrander, A.; Schröter, J.; Boebel, O.

    2009-04-01

    The Gravity Recovery and Climate Experiment (GRACE) provides estimates of the Earth's static and time-variant gravity field. Solutions from various processing centres (GFZ, CSR, GRGS, JPL etc.) enable us to determine mass redistributions on the globe. Given that land signals are generally large compared to anomalies over the ocean, an assessment of the latter requires a particularly careful filtering of the data. We utilized the Finite Element Sea-Ice Ocean Model (FESOM) to develop a filtering algorithm which relies on the spatial coherency of ocean bottom pressure (OBP) anomalies. Taking large-scale circulation patterns into account, the new filter yields an improved representation of OBP (i.e. ocean mass) variability in the filtered GRACE data. In order to investigate the representation of Antarctic Circumpolar Current (ACC) variability in the pattern-filtered GRACE retrievals, an analysis of OBP anomalies in FESOM results and in-situ measurements has been performed. A bottom pressure recorder array in the ACC region south of Africa (36°S-58°S, 1°W-7°E) provides data from 2002-2008. Based on anomalies of OBP gradients between individual instruments, these in-situ measurements give an estimate of the overall transport variability as well as of the movement of ACC fronts and transport redistribution between different sectors of the ACC. The validation of simulated and satellite-derived OBP anomaly gradients against these data yields a measure for the representation of this variability in FESOM and GRACE. Furthermore, model simulations are used to assess the relation between transport variations in individual filaments of the Southern Ocean and total transport variability in this and other sectors of the ACC.

  15. In situ measurement of atmospheric krypton and xenon on Mars with Mars Science Laboratory

    NASA Astrophysics Data System (ADS)

    Conrad, P. G.; Malespin, C. A.; Franz, H. B.; Pepin, R. O.; Trainer, M. G.; Schwenzer, S. P.; Atreya, S. K.; Freissinet, C.; Jones, J. H.; Manning, H.; Owen, T.; Pavlov, A. A.; Wiens, R. C.; Wong, M. H.; Mahaffy, P. R.

    2016-11-01

    Mars Science Laboratory's Sample Analysis at Mars (SAM) investigation has measured all of the stable isotopes of the heavy noble gases krypton and xenon in the martian atmosphere, in situ, from the Curiosity Rover at Gale Crater, Mars. Previous knowledge of martian atmospheric krypton and xenon isotope ratios has been based upon a combination of the Viking mission's krypton and xenon detections and measurements of noble gas isotope ratios in martian meteorites. However, the meteorite measurements reveal an impure mixture of atmospheric, mantle, and spallation contributions. The xenon and krypton isotopic measurements reported here include the complete set of stable isotopes, unmeasured by Viking. The new results generally agree with Mars meteorite measurements but also provide a unique opportunity to identify various non-atmospheric heavy noble gas components in the meteorites. Kr isotopic measurements define a solar-like atmospheric composition, but deviating from the solar wind pattern at 80Kr and 82Kr in a manner consistent with contributions originating from neutron capture in Br. The Xe measurements suggest an intriguing possibility that isotopes lighter than 132Xe have been enriched to varying degrees by spallation and neutron capture products degassed to the atmosphere from the regolith, and a model is constructed to explore this possibility. Such a spallation component, however, is not apparent in atmospheric Xe trapped in the glassy phases of martian meteorites.

  16. Evolution of a natural debris flow: In situ measurements of flow dynamics, video imagery, and terrestrial laser scanning

    USGS Publications Warehouse

    McCoy, S.W.; Kean, J.W.; Coe, J.A.; Staley, D.M.; Wasklewicz, T.A.; Tucker, G.E.

    2010-01-01

    Many theoretical and laboratory studies have been undertaken to understand debris-flow processes and their associated hazards. However, complete and quantitative data sets from natural debris flows needed for confirmation of these results are limited. We used a novel combination of in situ measurements of debris-flow dynamics, video imagery, and pre- and postflow 2-cm-resolution digital terrain models to study a natural debris-flow event. Our field data constrain the initial and final reach morphology and key flow dynamics. The observed event consisted of multiple surges, each with clear variation of flow properties along the length of the surge. Steep, highly resistant, surge fronts of coarse-grained material without measurable pore-fluid pressure were pushed along by relatively fine-grained and water-rich tails that had a wide range of pore-fluid pressures (some two times greater than hydrostatic). Surges with larger nonequilibrium pore-fluid pressures had longer travel distances. A wide range of travel distances from different surges of similar size indicates that dynamic flow properties are of equal or greater importance than channel properties in determining where a particular surge will stop. Progressive vertical accretion of multiple surges generated the total thickness of mapped debris-flow deposits; nevertheless, deposits had massive, vertically unstratified sedimentological textures. ?? 2010 Geological Society of America.

  17. Simultaneous infrared reflection absorption spectroscopy and quartz crystal microbalance measurements for in situ studies of the metal/atmosphere interface

    SciTech Connect

    Aastrup, T.; Leygraf, C.

    1997-09-01

    A new experimental setup for in situ studies of the metal/atmosphere interface has been developed based on simultaneous infrared reflection absorption spectroscopy (IRAS) and quartz crystal microbalance (QCM) measurements of a metal surface. It consists of an in situ chamber in which the metal can be exposed to a well-controlled atmosphere. Four external devices are connected to the in situ chamber; a Fourier transform infrared spectrometer with external optical compartments, a QCM sensor probe with a frequency counter, a corrosive air generator, and a corrosive air analyzing system. In order to demonstrate the capability of the IRAS/QCM setup, copper was exposed to purified air at 80% relative humidity and 25 C. Under these exposure conditions, the interface between copper and air consists of cuprous oxide and water physisorbed on the oxide. The kinetics of the cuprous oxide formation could be followed in situ with both techniques. The combined IRAS/QCM results show excellent agreement with previous combined IRAS and cathodic reduction measurements and with optical calculations of the IRAS response. Under these conditions, the detection limit in terms of an equivalent Cu{sub 2}O film thickness is 10 {angstrom} for IRAS in situ analysis and 2 {angstrom} for QCM in situ analysis, respectively.

  18. Deriving seasonal dynamics in ecosystem properties of semi-arid savanna grasslands from in situ-based hyperspectral reflectance

    NASA Astrophysics Data System (ADS)

    Tagesson, T.; Fensholt, R.; Huber, S.; Horion, S.; Guiro, I.; Ehammer, A.; Ardo, J.

    2015-08-01

    This paper investigates how hyperspectral reflectance (between 350 and 1800 nm) can be used to infer ecosystem properties for a semi-arid savanna grassland in West Africa using a unique in situ-based multi-angular data set of hemispherical conical reflectance factor (HCRF) measurements. Relationships between seasonal dynamics in hyperspectral HCRF and ecosystem properties (biomass, gross primary productivity (GPP), light use efficiency (LUE), and fraction of photosynthetically active radiation absorbed by vegetation (FAPAR)) were analysed. HCRF data (ρ) were used to study the relationship between normalised difference spectral indices (NDSIs) and the measured ecosystem properties. Finally, the effects of variable sun sensor viewing geometry on different NDSI wavelength combinations were analysed. The wavelengths with the strongest correlation to seasonal dynamics in ecosystem properties were shortwave infrared (biomass), the peak absorption band for chlorophyll a and b (at 682 nm) (GPP), the oxygen A band at 761 nm used for estimating chlorophyll fluorescence (GPP and LUE), and blue wavelengths (ρ412) (FAPAR). The NDSI with the strongest correlation to (i) biomass combined red-edge HCRF (ρ705) with green HCRF (ρ587), (ii) GPP combined wavelengths at the peak of green reflection (ρ518, ρ556), (iii) LUE combined red (ρ688) with blue HCRF (ρ436), and (iv) FAPAR combined blue (ρ399) and near-infrared (ρ1295) wavelengths. NDSIs combining near infrared and shortwave infrared were strongly affected by solar zenith angles and sensor viewing geometry, as were many combinations of visible wavelengths. This study provides analyses based upon novel multi-angular hyperspectral data for validation of Earth-observation-based properties of semi-arid ecosystems, as well as insights for designing spectral characteristics of future sensors for ecosystem monitoring.

  19. An Instrument for In Situ Measuring the Volume Scattering Function of Water: Design, Calibration and Primary Experiments

    PubMed Central

    Li, Cai; Cao, Wenxi; Yu, Jing; Ke, Tiancun; Lu, Guixin; Yang, Yuezhong; Guo, Chaoying

    2012-01-01

    The optical volume scattering function (VSF) of seawater is a fundamental property used in the calculation of radiative transfer for applications in the study of the upper-ocean heat balance, the photosynthetic productivity of the ocean, and the chemical transformation of photoreactive compounds. A new instrument to simultaneously measure the VSF in seven directions between 20° to 160°, the attenuation coefficient, and the depth of water is presented. The instrument is self-contained and can be automatically controlled by the depth under water. The self-contained data can be easily downloaded by an ultra-short-wave communication system. A calibration test was performed in the laboratory based on precise estimation of the scattering volume and optical radiometric calibration of the detectors. The measurement error of the VSF measurement instrument has been estimated in the laboratory based on the Mie theory, and the average error is less than 12%. The instrument was used to measure and analyze the variation characteristics of the VSF with angle, depth and water quality in Daya Bay for the first time. From these in situ data, we have found that the phase functions proposed by Fournier-Forand, measured by Petzold in San Diego Harbor and Sokolov in Black Sea do not fit with our measurements in Daya. These discrepancies could manly due to high proportion of suspended calcium carbonate mineral-like particles with high refractive index in Daya Bay. PMID:22666043

  20. An instrument for in situ measuring the volume scattering function of water: design, calibration and primary experiments.

    PubMed

    Li, Cai; Cao, Wenxi; Yu, Jing; Ke, Tiancun; Lu, Guixin; Yang, Yuezhong; Guo, Chaoying

    2012-01-01

    The optical volume scattering function (VSF) of seawater is a fundamental property used in the calculation of radiative transfer for applications in the study of the upper-ocean heat balance, the photosynthetic productivity of the ocean, and the chemical transformation of photoreactive compounds. A new instrument to simultaneously measure the VSF in seven directions between 20° to 160°, the attenuation coefficient, and the depth of water is presented. The instrument is self-contained and can be automatically controlled by the depth under water. The self-contained data can be easily downloaded by an ultra-short-wave communication system. A calibration test was performed in the laboratory based on precise estimation of the scattering volume and optical radiometric calibration of the detectors. The measurement error of the VSF measurement instrument has been estimated in the laboratory based on the Mie theory, and the average error is less than 12%. The instrument was used to measure and analyze the variation characteristics of the VSF with angle, depth and water quality in Daya Bay for the first time. From these in situ data, we have found that the phase functions proposed by Fournier-Forand, measured by Petzold in San Diego Harbor and Sokolov in Black Sea do not fit with our measurements in Daya. These discrepancies could manly due to high proportion of suspended calcium carbonate mineral-like particles with high refractive index in Daya Bay.

  1. Boundary Layer Transition Flight Experiment Overview and In-Situ Measurements

    NASA Technical Reports Server (NTRS)

    Berger, Karen T.; Anderson, Brian P.; Campbell, Charles H.; Garske, Michael T.; Saucedo, Luis A.; Kinder, Gerald R.

    2010-01-01

    In support of the Boundary Layer Transition Flight Experiment (BLT FE) Project, a manufactured protuberance tile was installed on the port wing of Space Shuttle Orbiter Discovery for the flights of STS-119, STS-128 and STS-131. Additional instrumentation was installed in order to obtain more spatially resolved measurements downstream of the protuberance. This paper provides an overview of the BLT FE Project. Significant efforts were made to place the protuberance at an appropriate location on the Orbiter and to design the protuberance to withstand the expected environments. A high-level overview of the in-situ flight data is presented, along with a summary of the comparisons between pre- and post-flight analysis predictions and flight data. Comparisons show that predictions for boundary layer transition onset time closely match the flight data, while predicted temperatures were significantly higher than observed flight temperatures.

  2. IN SITU INFRARED MEASUREMENTS OF FREE-FLYING SILICATE DURING CONDENSATION IN THE LABORATORY

    SciTech Connect

    Ishizuka, Shinnosuke; Kimura, Yuki; Sakon, Itsuki

    2015-04-20

    We developed a new experimental system for infrared (IR) measurements on free-flying nucleating nanoparticles in situ and applied it to studies on silicate particles. We monitored the condensation of magnesium-bearing silicate nanoparticles from thermally evaporated magnesium and silicon monoxide vapor under an atmosphere of oxygen and argon. The IR spectrum of newly condensed particles showed a spectral feature for non-crystalline magnesium-bearing silicate that is remarkably consistent with the IR spectrum of astronomically observed non-crystalline silicate around oxygen-rich evolved stars. The silicate crystallized at <500 K and eventually developed a high crystallinity. Because of the size effects of nanoparticles, the silicate would be expected to be like a liquid at least during the initial stages of nucleation and growth. Our experimental results therefore suggest decreasing the possible formation temperature of crystalline silicates in dust formation environments with relatively higher pressure.

  3. In Situ Measurements of the Flow around a Single Vertical-Axis Wind Turbine

    NASA Astrophysics Data System (ADS)

    Brownstein, Ian; Araya, Daniel; Kinzel, Matthias; Dabiri, John

    2014-11-01

    Laboratory studies of model vertical-axis wind turbines (VAWTs) are typically unable to match both the Reynolds number (Re) and tip speed ratio (TSR) of full-scale wind turbines. In order to match both relevant parameters, a quantitative flow visualization method was developed to take in situ measurements of the flow around full-scale VAWTs. An apparatus was constructed to deploy a horizontal sheet of smoke upstream of the turbine at the mid-span of the rotor. Quantitative results were obtained by tracking the evolution of this smoke sheet using a PIV algorithm. This method will be demonstrated through a comparative study of three- and five-bladed VAWTs at the Field Laboratory for Optimized Wind Energy (FLOWE) in Lancaster, CA. Additionally, results will be presented in comparison with previous laboratory studies to help determine the dependence of the flow physics on Re and TSR.

  4. In situ observation and measurement of composites subjected to extremely high temperature

    NASA Astrophysics Data System (ADS)

    Fang, Xufei; Yu, Helong; Zhang, Guobing; Su, Hengqiang; Tang, Hongxiang; Feng, Xue

    2014-03-01

    In this work, we develop an instrument to study the ablation and oxidation process of materials such as C/SiC (carbon fiber reinforced silicon carbide composites) and ultra-high temperature ceramic in extremely high temperature environment. The instrument is integrated with high speed cameras with filtering lens, infrared thermometers and water vapor generator for image capture, temperature measurement, and humid atmosphere, respectively. The ablation process and thermal shock as well as the temperature on both sides of the specimen can be in situ monitored. The results show clearly the dynamic ablation and liquid oxide flowing. In addition, we develop an algorithm for the post-processing of the captured images to obtain the deformation of the specimens, in order to better understand the behavior of the specimen subjected to high temperature.

  5. In situ observation and measurement of composites subjected to extremely high temperature.

    PubMed

    Fang, Xufei; Yu, Helong; Zhang, Guobing; Su, Hengqiang; Tang, Hongxiang; Feng, Xue

    2014-03-01

    In this work, we develop an instrument to study the ablation and oxidation process of materials such as C/SiC (carbon fiber reinforced silicon carbide composites) and ultra-high temperature ceramic in extremely high temperature environment. The instrument is integrated with high speed cameras with filtering lens, infrared thermometers and water vapor generator for image capture, temperature measurement, and humid atmosphere, respectively. The ablation process and thermal shock as well as the temperature on both sides of the specimen can be in situ monitored. The results show clearly the dynamic ablation and liquid oxide flowing. In addition, we develop an algorithm for the post-processing of the captured images to obtain the deformation of the specimens, in order to better understand the behavior of the specimen subjected to high temperature.

  6. Monte Carlo based calibration of scintillation detectors for laboratory and in situ gamma ray measurements.

    PubMed

    van der Graaf, E R; Limburg, J; Koomans, R L; Tijs, M

    2011-03-01

    The calibration of scintillation detectors for gamma radiation in a well characterized setup can be transferred to other geometries using Monte Carlo simulations to account for the differences between the calibration and the other geometry. In this study a calibration facility was used that is constructed from bricks of well-known activity concentrations of ⁴⁰K and of radionuclides from the ²³⁸U- and ²³²Th-series. Transfer of the calibration was attempted to a Marinelli beaker geometry with the detector inside a lead shield and to an in situ application with the detector positioned on a sand bed. In general this resulted in good correspondence (within 5-10%) between the activity concentrations derived using the transferred calibration and activities that were derived by independent measurements. Some discrepancies were identified that were attributed to coincident summing in the natural decay series and interference of radon. PMID:21251733

  7. Indoor and outdoor in situ high-resolution gamma radiation measurements in urban areas of Cyprus.

    PubMed

    Svoukis, E; Tsertos, H

    2007-01-01

    In situ, high-resolution, gamma-ray spectrometry of a total number of 70 outdoor and 20 indoor representative measurements were performed in preselected, common locations of the main urban areas of Cyprus. Specific activities and gamma absorbed dose rates in air due to the naturally occurring radionuclides of (232)Th and (238)U series, and (40)K are determined and discussed. Effective dose rate to the Cyprus population due to terrestrial gamma radiation is derived directly from this work. The results obtained outdoors match very well with those derived previously by high-resolution gamma spectrometry of soil samples, which were collected from the main island bedrock surface. This implies that the construction and building materials in urban areas do not affect the external gamma dose rate; thus they are mostly of local origin. Finally, the indoor/outdoor gamma dose ratio was found to be 1.4 +/- 0.5. PMID:17065195

  8. In Situ Infrared Measurements of Free-flying Silicate during Condensation in the Laboratory

    NASA Astrophysics Data System (ADS)

    Ishizuka, Shinnosuke; Kimura, Yuki; Sakon, Itsuki

    2015-04-01

    We developed a new experimental system for infrared (IR) measurements on free-flying nucleating nanoparticles in situ and applied it to studies on silicate particles. We monitored the condensation of magnesium-bearing silicate nanoparticles from thermally evaporated magnesium and silicon monoxide vapor under an atmosphere of oxygen and argon. The IR spectrum of newly condensed particles showed a spectral feature for non-crystalline magnesium-bearing silicate that is remarkably consistent with the IR spectrum of astronomically observed non-crystalline silicate around oxygen-rich evolved stars. The silicate crystallized at <500 K and eventually developed a high crystallinity. Because of the size effects of nanoparticles, the silicate would be expected to be like a liquid at least during the initial stages of nucleation and growth. Our experimental results therefore suggest decreasing the possible formation temperature of crystalline silicates in dust formation environments with relatively higher pressure.

  9. In situ measurements of the radiation stability of amino acids at 15-140 K

    NASA Astrophysics Data System (ADS)

    Gerakines, Perry A.; Hudson, Reggie L.; Moore, Marla H.; Bell, Jan-Luca

    2012-08-01

    We present new kinetics data on the radiolytic destruction of amino acids measured in situ with infrared spectroscopy. Samples were irradiated at 15, 100, and 140 K with 0.8-MeV protons, and amino-acid decay was followed at each temperature with and without H2O present. Observed radiation products included CO2 and amines, consistent with amino-acid decarboxylation. The half-lives of glycine, alanine, and phenylalanine were estimated for various extraterrestrial environments. Infrared spectral changes demonstrated the conversion from the non-zwitterion structure NH2sbnd CH2(R)sbnd COOH at 15 K to the zwitterion structure +NH3sbnd CH2(R)sbnd COO- at 140 K for each amino acid studied.

  10. In situ measurement of interstellar silicon carbide in two CM chondrite meteorites

    NASA Technical Reports Server (NTRS)

    Alexander, C. M. O'D.; Swan, P.; Walker, R. M.

    1990-01-01

    The first in situ observations of isotopically anomalous SiC are reported. The grains were found by X-ray mapping of polished sections of two chondritic meteorites, Cold Bokkeveld and Murchison. Ion microprobe measurements showed C-13 enrichments, delta C-13, from 199 to 2800 per mil, proving that the grains are indigenous. SiC grains are revealed only as isolated matrix particles, ruling out the possibility that SiC grains were brought into the solar system as inclusions in larger grains, which protected them from destruction in the solar nebula. Several of the SiC grains are cracked, suggesting that the etching treatment may result in size distributions biased toward smaller grains.

  11. In-Situ Measurements of the Radiation Stability of Amino Acids at 15-140 K

    NASA Technical Reports Server (NTRS)

    Gerakines, Perry A.; Hudson, Reggie L.; Moore, Marla H.; Bell, Jan-Luca

    2012-01-01

    We present new kinetics data on the radiolytic destruction of amino acids measured in situ with infrared spectroscopy. Samples were irradiated at 15, 100, and 140 K with D.8-MeV protons, and amino-acid decay was followed at each temperature with and without H2O present. Observed radiation products included CO2 and amines, consistent with amino-acid decarboxylation. The half-lives of glycine, alanine, and phenylalanine were estimated for various extraterrestrial environments. Infrared spectral changes demonstrated the conversion from the non-zwitterion structure NH2-CH2(R)-COOH at 15 K to the zwitterion structure +NH3-CH2(R)-COO- at 140 K for each amino acid studied.

  12. In situ electrical conductivity measurements of H2O under static pressure up to 28 GPa

    NASA Astrophysics Data System (ADS)

    Liu, Bao; Gao, Yang; Han, Yonghao; Ma, Yanzhang; Gao, Chunxiao

    2016-08-01

    The in situ electrical conductivity measurements on water in both solid state and liquid state were performed under pressure up to 28 GPa and temperature from 77 K to 300 K using a microcircuit fabricated on a diamond anvil cell (DAC). Water chemically ionization mainly contributes to electrical conduction in liquid state, which is in accord with the results obtained under dynamic pressure. Energy band theory of liquid water was used to understand effect of static pressure on electrical conduction of water. The electric conductivity of H2O decreased discontinuously by four orders of magnitude at 0.7-0.96 GPa, indicating water frozen at this P-T condition. Correspondingly, the conduction of H2O in solid state is determined by arrangement and bending of H-bond in ice VI and ice VII. Based on Jaccard theory, we have concluded that the charge carriers of ice are already existing ions and Bjerrum defects.

  13. Dynamics of graphite fiber intercalation: In situ resistivity measurements with a four point probe

    NASA Technical Reports Server (NTRS)

    Jaworske, D. A.

    1984-01-01

    The dynamics of ferric chloride intercalation of single graphite fibers were studied, in situ, using a four point dc bridge. Measurements before, during and after the intercalation showed that the intercalation occurred within minutes at 200 C. Changes in fiber resistivity after exposure to air suggested hydration of the graphite intercalation compound. Deintercalation of the ferric chloride was initiated at temperatures in excess of 400 C. cycling the intercalant into and out of the graphite fiber gave no improvements in fiber resistivity. The activation energy of the ferric chloride intercalation reaction was found to be 17 + or - 4 kcal/mol 1 consistent with the concept of a preliminary nucleation step in the intercalation reaction.

  14. In situ time-resolved measurements of carbon nanotube and nanohorn growth

    SciTech Connect

    Geohegan, David B; Puretzky, Alexander A; Styers-Barnett, David J; Hu, Hui; Zhao, Bin; Cui, Hongtao; Rouleau, Christopher M; Eres, Gyula; Jackson, Jeremy Joseph; Wood, Richard F; Pannala, Sreekanth; Wells, Jack C

    2007-01-01

    Growth mechanisms of carbon nanotubes are investigated and compared for both high- and low-temperature synthesis methods through experiments utilizing time-resolved, in situ imaging and spectros-copy. High-speed videography and pyrometry measured the timeframes for growth for single-wall car-bon nanotubes (SWNTs) and nanohorns (SWNHs) by laser vaporization (LV) at 1150 C, revealing that C can self-assemble at high temperatures preferentially into SWNH structures without catalyst assistance at rates comparable to catalyst-assisted SWNT growth by either laser vaporization or chemical vapor depo-sition (CVD). Laser interferometry and videography reveal the coordinated growth of vertically-aligned nanotube arrays (VANTAs) by CVD at 550-900 C.

  15. Bio-Optical Properties of the Arabian Sea as Determined by In Situ and Sea WiFS Data

    NASA Technical Reports Server (NTRS)

    Trees, Charles C.

    1997-01-01

    The overall objective of this work was to characterize optical and fluorescence properties in the euphotic zone during two British Ocean Flux Study (BOFS) Arabian Sea cruises. This was later expanded in 1995 to include three U.S. JGOFS Arabian Sea Cruises. The region was to be divided into one or more "bio-optical provinces," within each of which a single set of regression models was to be developed to relate the vertical distribution of irradiance attenuation and normalized fluorescence (SF and NF) to remote sensing reflectance and diffuse attenuation coefficient. The working hypothesis was that over relatively large spatial and temporal scales, the vertical profiles of bio-optical properties were predictable. The specific technical objectives were: (1) To characterize the vertical distribution of the inherent and apparent optical properties by measuring downwelling and upwelling irradiances, upwelling radiances, scalar irradiance of PAR, and beam transmissions at each station - from these data, spectral diffuse attenuation coefficients, irradiance reflectances, remote sensing reflectances, surface-leaving radiances and beam attenuation coefficients were determined; (2) To characterize the spectral absorption of total particulate, detrital, and dissolved organic material at each station from discrete water samples; (3) To describe the vertical distribution of photoadaptive properties in the water column by measuring profiles of stimulated (SF) and natural (NF) fluorescence and examining relationships between SF and NF as a function of diffuse optical depth, pigment biomass and primary productivity; and (4) To establish locally derived, in-water algorithms relating remote sensing reflectance spectra to diffuse attenuation coefficients, phytoplankton pigment concentrations and primary productivity, through intercomparisons with in situ measurements, for application to SeaWiFS data.

  16. Applications of in situ optical measurements in ecological and biogeochemical studies - a framework for a user-driven national network

    NASA Astrophysics Data System (ADS)

    Bergamaschi, B. A.; Pellerin, B. A.; Downing, B. D.; Saraceno, J.; Aiken, G.; Stumpner, P.

    2010-12-01

    A critical challenge for understanding the dynamics between water quality, and ecological processes is obtaining data at time scales in which changes occur. Traditional, discrete sampling, approaches for data collection are often limited by analytical and field costs, site access, and logistical challenges, for long-term sampling at a large number of sites. The timescales of change, however, are often minutes, hours, or years. In situ optical (absorbance and fluorescence) instruments offer opportunities to help overcome these difficulties by directly or indirectly measuring constituents of interest. In situ optical instrumentation have been in use in oceanographic studies for well over 50 years, and as advances in the science, engineering and technology of these sensors have improved, optical sensors have become more commercially viable and available for research. We present several examples that highlight applications of in situ optical measurements for understanding dynamics in stream, river, and estuary systems. Examples illustrate the utility of in situ optical sensors for studies over short-duration events of days to weeks (diurnal cycles, tidal cycles, storm events and snowmelt periods) as well as longer-term continuous monitoring for months to years. We also highlight applied in situ optical measurements as proxies for constituents that are difficult and expensive to measure at high spatiotemporal resolution, for example, dissolved organic carbon, dissolved organic nitrogen, mercury and methylmercury, trihalomethane precursors, harmful algal blooms, and others. We propose that relatively simple absorbance and fluorescence measurements made in situ could be incorporated into short and long-term ecological research and monitoring programs, resulting in advanced understanding of sources that contribute to water quality improvements or degradation, contaminant and carbon cycling, and the occurrence and persistence of harmful algal blooms. Linking these efforts

  17. The gravity anomaly field in the Gulf of Bothnia spatially characterized from satellite altimetry and in situ measurements

    NASA Astrophysics Data System (ADS)

    Noréus, J. P.; Nyborg, M. R.; Hayling, K. L.

    1997-06-01

    The gravity anomaly field in the Gulf of Bothnia has been investigated using (1) in situ high-precision measurements conducted on the sea ice during cold winters, and (2) gravity anomaly profiles computed from collinear satellite radar altimeter data from the Geosat ERM and the Topex/Poseidon missions. The in situ measurements were obtained from a collaboration between the Finnish Geodetic Institute, the Geological Survey of Sweden (SGU) and the National Survey of Sweden (LMV), and were processed with the geostatistical method called kriging. These data were used to calibrate the altimetric gravity. Altimetry generally resolves features of 20 km wavelength or longer, and in some cases detects shorter features when a sampling interval of 10 Hz is used. The precision of the along-track one-dimensional altimetric profiles corresponds to a gravity uncertainty of 2-3 mGal, and comparison with in situ measured gravity show 4 mGal discrepancy. The precision of the in situ measurements is better. However, depending on the sampling distance, the estimation uncertainty interior the in situ data areas may be up to 5 mGal between neighbouring data points. In regions with in situ data gaps, the estimation uncertainty of the in situ gravity measurements is rapidly increasing to a maximum of 9 mGal. An improved estimation uncertainty of 4-9 mGal was obtained in the same data gap regions with the support of satellite altimetry. Altimetric gravity is therefore used to estimate the gravity field in such regions, and to spatially characterize the gravity field in the Gulf of Bothnia.

  18. In situ measurement of tissue impedance using an inductive coupling interface circuit.

    PubMed

    Chiu, Hung-Wei; Chuang, Jia-min; Lu, Chien-Chi; Lin, Wei-Tso; Lin, Chii-Wann; Lin, Mu-Lien

    2013-06-01

    In this work, a method of an inductive coupling impedance measurement (ICIM) is proposed for measuring the nerve impedance of a dorsal root ganglion (DRG) under PRF stimulation. ICIM provides a contactless interface for measuring the reflected impedance by an impedance analyzer with a low excitation voltage of 7 mV. The paper develops a calibration procedure involving a 50-Ω reference resistor to calibrate the reflected resistance for measuring resistance of the nerve in the test. A de-embedding technique to build the equivalent transformer circuit model for the ICIM circuit is also presented. A batteryless PRF stimulator with ICIM circuit demonstrated good accuracy for the acute measurement of DRG impedance both in situ and in vivo. Besides, an in vivo animal experiment was conducted to show that the effectiveness of pulsed radiofrequency (PRF) stimulation in relieving pain gradually declined as the impedance of the stimulated nerve increased. The experiment also revealed that the excitation voltage for measuring impedance below 25 mV can prevent the excitation of a nonlinear response of DRG.

  19. Comparison of different methods for the in situ measurement of forest litter moisture content

    NASA Astrophysics Data System (ADS)

    Schunk, C.; Ruth, B.; Leuchner, M.; Wastl, C.; Menzel, A.

    2015-06-01

    Dead fine fuel (e.g. litter) moisture content is an important parameter for both forest fire and ecological applications as it is related to ignitability, fire behavior as well as soil respiration. However, the comprehensive literature review in this paper shows that there is no easy-to-use method for automated measurements available. This study investigates the applicability of four different sensor types (permittivity and electrical resistance measuring principles) for this measurement. Comparisons were made to manual gravimetric reference measurements carried out almost daily for one fire season and overall agreement was good (highly significant correlations with 0.792 ≦ r ≦ 0.947). Standard deviations within sensor types were linearly correlated to daily sensor mean values; however, above a certain threshold they became irregular, which may be linked to exceedance of the working ranges. Thus, measurements with irregular standard deviations were considered unusable and calibrations of all individual sensors were compared for useable periods. A large drift in the sensor raw value-litter moisture-relationship became obvious from drought to drought period. This drift may be related to installation effects or settling and decomposition of the litter layer throughout the fire season. Because of the drift and the in situ calibration necessary, it cannot be recommended to use the methods presented here for monitoring purposes. However, they may be interesting for scientific studies when some manual fuel moisture measurements are made anyway. Additionally, a number of potential methodological improvements are suggested.

  20. In-situ membrane resistance measurements in PEFC by fast current pulses

    SciTech Connect

    Buechi, F.N.; Scherer, G.G.; Marek, A.

    1994-12-31

    A solid-state current pulse generator for in situ membrane resistance measurements by superimposed square current pulses in polymer electrolyte fuel cells was designed and built. The choice of the measuring technique and of parameters of the instrumentation was based on a critical analysis of the relevant electrochemical and physical processes. The last stage of the generator is located in an active head directly attached to the fuel cell. This permits the generation of 5 A pulses with extremely fast and clean trailing edges (decay time {le} 5 ns), which in turn makes it possible to measure the voltage transient induced by the current decay, with GHz resolution. By measurements in this time window it is possible to accurate separate of the ohmic series resistance of the cell (membrane resistance) from the polarization of the electrochemical interfaces. Because the pulse current path is independent of the d.c. loop, the resistance can be measured independently of the d.c. value, i.e. under high current density conditions. The instrument was tested and the results analyzed for accuracy. Resistances down to 2 m{Omega} can be measured with an error of < 5%.

  1. Reactor for in situ measurements of spatially resolved kinetic data in heterogeneous catalysis.

    PubMed

    Horn, R; Korup, O; Geske, M; Zavyalova, U; Oprea, I; Schlögl, R

    2010-06-01

    The present work describes a reactor that allows in situ measurements of spatially resolved kinetic data in heterogeneous catalysis. The reactor design allows measurements up to temperatures of 1300 degrees C and 45 bar pressure, i.e., conditions of industrial relevance. The reactor involves reactants flowing through a solid catalyst bed containing a sampling capillary with a side sampling orifice through which a small fraction of the reacting fluid (gas or liquid) is transferred into an analytical device (e.g., mass spectrometer, gas chromatograph, high pressure liquid chromatograph) for quantitative analysis. The sampling capillary can be moved with microm resolution in or against flow direction to measure species profiles through the catalyst bed. Rotation of the sampling capillary allows averaging over several scan lines. The position of the sampling orifice is such that the capillary channel through the catalyst bed remains always occupied by the capillary preventing flow disturbance and fluid bypassing. The second function of the sampling capillary is to provide a well which can accommodate temperature probes such as a thermocouple or a pyrometer fiber. If a thermocouple is inserted in the sampling capillary and aligned with the sampling orifice fluid temperature profiles can be measured. A pyrometer fiber can be used to measure the temperature profile of the solid catalyst bed. Spatial profile measurements are demonstrated for methane oxidation on Pt and methane oxidative coupling on Li/MgO, both catalysts supported on reticulated alpha-Al(2)O(3) foam supports. PMID:20590252

  2. Properties of BaFe12O19 films prepared by laser deposition with in situ heating and post annealing

    NASA Astrophysics Data System (ADS)

    Lu, Y. F.; Song, W. D.

    2000-01-01

    BaFe12O19 films on (001) sapphire substrates are prepared by laser deposition with in situ heating and postannealing. The properties of the films are analyzed by x-ray diffractometry, vibrating sample magnetometer, atomic force microscopy, and Raman spectroscopy. The relationship among the coercivity, crystalline orientation, and grain shape and size is discussed. The film with coercivity of 5.1 kOe has been obtained by laser deposition with postannealing. The film with a preferential c-axis orientation normal to the film plane and the grains having good crystallinity with hexagonal symmetry have been obtained by laser deposition with in situ heating.

  3. A microchip integrating cell array positioning with in situ single-cell impedance measurement.

    PubMed

    Guo, Xiaoliang; Zhu, Rong; Zong, Xianli

    2015-10-01

    This paper presents a novel microarray chip integrating cell positioning with in situ, real-time and long-time impedance measurement on a single cell. The microchip integrates a plurality of quadrupole-electrode units (termed positioning electrodes) patterned into an array with pairs of planar electrodes (termed measuring electrodes) located at the centers of each quadrupole-electrode unit. The positioning electrodes are utilized to trap and position living cells onto the measuring electrodes based on negative dielectrophoresis (nDEP), while the measuring electrodes are used to measure impedances of the trapped single cells. Each measuring electrode has a small footprint area of 7 × 7 μm(2) to ensure inhabiting only one single cell on it. However, the electrode with a small surface area has a low double-layer capacitance when it is immersed in a liquid solution, thus generating a large double-layer impedance, which reduces the sensitivity for impedance measurement on the single cell. To enlarge the effective surface areas of the measuring electrodes, a novel surface-modification process is proposed to controllably construct gold nanostructures on the surfaces of the measuring electrodes while the positioning electrodes are unstained. The double layer capacitances of the modified electrodes are increased by about one order after surface-modification. The developed microchip is used to monitor the adhering behavior of a single HeLa cell by measuring its impedance spectra in real time. The measured impedance is analyzed and used to extract cellular electrical parameters, which demonstrated that the cell compresses the electrical double layer in the process of adherence and adheres onto the measuring electrodes after 4-5 hours. PMID:26282920

  4. A microchip integrating cell array positioning with in situ single-cell impedance measurement.

    PubMed

    Guo, Xiaoliang; Zhu, Rong; Zong, Xianli

    2015-10-01

    This paper presents a novel microarray chip integrating cell positioning with in situ, real-time and long-time impedance measurement on a single cell. The microchip integrates a plurality of quadrupole-electrode units (termed positioning electrodes) patterned into an array with pairs of planar electrodes (termed measuring electrodes) located at the centers of each quadrupole-electrode unit. The positioning electrodes are utilized to trap and position living cells onto the measuring electrodes based on negative dielectrophoresis (nDEP), while the measuring electrodes are used to measure impedances of the trapped single cells. Each measuring electrode has a small footprint area of 7 × 7 μm(2) to ensure inhabiting only one single cell on it. However, the electrode with a small surface area has a low double-layer capacitance when it is immersed in a liquid solution, thus generating a large double-layer impedance, which reduces the sensitivity for impedance measurement on the single cell. To enlarge the effective surface areas of the measuring electrodes, a novel surface-modification process is proposed to controllably construct gold nanostructures on the surfaces of the measuring electrodes while the positioning electrodes are unstained. The double layer capacitances of the modified electrodes are increased by about one order after surface-modification. The developed microchip is used to monitor the adhering behavior of a single HeLa cell by measuring its impedance spectra in real time. The measured impedance is analyzed and used to extract cellular electrical parameters, which demonstrated that the cell compresses the electrical double layer in the process of adherence and adheres onto the measuring electrodes after 4-5 hours.

  5. Stable water isotope and surface heat flux simulation using ISOLSM: Evaluation against in-situ measurements

    NASA Astrophysics Data System (ADS)

    Cai, Mick Y.; Wang, Lixin; Parkes, Stephen D.; Strauss, Josiah; McCabe, Matthew F.; Evans, Jason P.; Griffiths, Alan D.

    2015-04-01

    The stable isotopes of water are useful tracers of water sources and hydrological processes. Stable water isotope-enabled land surface modeling is a relatively new approach for characterizing the hydrological cycle, providing spatial and temporal variability for a number of hydrological processes. At the land surface, the integration of stable water isotopes with other meteorological measurements can assist in constraining surface heat flux estimates and discriminate between evaporation (E) and transpiration (T). However, research in this area has traditionally been limited by a lack of continuous in-situ isotopic observations. Here, the National Centre for Atmospheric Research stable isotope-enabled Land Surface Model (ISOLSM) is used to simulate the water and energy fluxes and stable water isotope variations. The model was run for a period of one month with meteorological data collected from a coastal sub-tropical site near Sydney, Australia. The modeled energy fluxes (latent heat and sensible heat) agreed reasonably well with eddy covariance observations, indicating that ISOLSM has the capacity to reproduce observed flux behavior. Comparison of modeled isotopic compositions of evapotranspiration (ET) against in-situ Fourier Transform Infrared spectroscopy (FTIR) measured bulk water vapor isotopic data (10 m above the ground), however, showed differences in magnitude and temporal patterns. The disparity is due to a small contribution from local ET fluxes to atmospheric boundary layer water vapor (∼1% based on calculations using ideal gas law) relative to that advected from the ocean for this particular site. Using ISOLSM simulation, the ET was partitioned into E and T with 70% being T. We also identified that soil water from different soil layers affected T and E differently based on the simulated soil isotopic patterns, which reflects the internal working of ISOLSM. These results highlighted the capacity of using the isotope-enabled models to discriminate

  6. DeepPIV: Measuring in situ Biological-Fluid Interactions from the Surface to Benthos

    NASA Astrophysics Data System (ADS)

    Katija, K.; Sherman, A.; Graves, D.; Kecy, C. D.; Klimov, D.; Robison, B. H.

    2015-12-01

    The midwater region of the ocean (below the euphotic zone and above the benthos) is one of the largest ecosystems on our planet, yet it remains one of the least explored. Little known marine organisms that inhabit midwater have developed strategies for swimming and feeding that ultimately contributes to their evolutionary success, and may inspire engineering solutions for societally relevant challenges. Fluid mechanics governs the interactions that midwater organisms have with their physical environment, but limited access to midwater depths and lack of non-invasive methods to measure in situ small-scale fluid motions prevent these interactions from being better understood. Significant advances in underwater vehicle technologies have only recently improved access to midwater. Unfortunately, in situ small-scale fluid mechanics measurement methods are still lacking in the oceanographic community. Here we present DeepPIV, an instrumentation package that can be affixed to remotely operated underwater vehicles that quantifies small-scale fluid motions from the surface of the ocean down to 4000 m depths. Utilizing ambient, suspended particulate in the coastal regions of Monterey Bay, fluid-structure interactions are evaluated on a range of marine organisms in midwater. Initial science targets include larvaceans, biological equivalents of flapping flexible foils, that create mucus houses to filter food. Little is known about the structure of these mucus houses and the function they play in selectively filtering particles, and these dynamics can serve as particle-mucus models for human health. Using DeepPIV, we reveal the complex structures and flows generated within larvacean mucus houses, and elucidate how these structures function.

  7. An in-situ electropolymerization based sensor for measuring salt content in crude oil.

    PubMed

    Aleisa, Rashed M; Akmal, Naim

    2015-01-01

    Determining salt content is a vital procedure in the petroleum industry during the process of crude oil transportation, refining and production. Monitoring the salinity value using a fast and direct technique can substantially lower the cost of crude oil in its processing and its production stages. In the present work, a novel analytical method was developed to detect the amount of salt present in crude oil in a quick and reliable manner. The measurement is based on the rate of in-situ electropolymerization of a monomer such as aniline in association with the salt content in the crude oil. The salt dispersed in the hydrocarbon matrix is used as an electrolyte in the electrolytic system to induce an electropolymerization reaction upon the induction of voltages, in which the salt content is measured corresponding to the polymeric film formation on the working electrode surface. Acetonitrile and N-methylpyrrolidone (NMP) were used in the electrochemical cell as solvents, and cyclic voltammetry tests were performed for Arabian crude oil solutions in the presence of aniline. The method has shown an excellent detection response for very low concentrations of salt. Four Arabian crude oils with salt concentrations of 34.2, 28.5, 14.3 and 5.71 mg L(-1) have produced current intensity of 180.1, 172.6, 148.1 and 134.2 µA at an applied current potential of 1.75 V (vs. Ag/AgCl), respectively. A Calibration curve was obtained in the range of 5-35 mg L(-1), giving limits of detection and quantitation at 1.98 and 5.95 mg L(-1), respectively. The in-situ electropolymerization based sensor has significant advantages over the existing techniques of salt monitoring in crude oil such as fast response, temperature independency, electrode stability, and minimum sample preparation.

  8. Comparison of Water Potentials Measured by In Situ Psychrometry and Pressure Chamber in Morphologically Different Species 1

    PubMed Central

    Turner, Neil C.; Spurway, R. A.; Schulze, E.-D.

    1984-01-01

    Leaf water potentials measured by in situ psychrometry were compared with leaf water potentials measured by the pressure chamber technique at various values of water potential in Helianthus annuus, Helianthus nuttallii, Vigna unguiculata, Nerium oleander, Pistacia vera, and Corylus avellana. In V. unguiculata, the leaf water potentials measured by the in situ psychrometer oscillated at the same periodicity as, and proportional to, the leaf conductance. In all species, potentials measured by in situ psychrometers operating in the psychrometric mode were linearly correlated with potentials measured with the pressure chamber. However, the in situ psychrometers underestimated the leaf water potential in the two Helianthus species at low water potentials and overestimated the water potential in P. vera, N. oleander, and C. avellana. The underestimation in the two Helianthus species at low water potentials resulted from differences in water potential across the leaf. The overestimation in P. vera, N. oleander, and C. avellana was considered to arise from low epidermal conductances in these species even after abrasion of the cuticle. Pressure-volume studies with Lycopersicon esculentum showed that less water was expressed from distal than proximal leaflets when the whole leaf was slowly pressurized. The implication of this for water relations characteristics obtained by pressure-volume techniques is discussed. We conclude that in situ psychrometers are suitable for following dynamic changes in leaf water potential, but should be used with caution on leaves with low epidermal conductances. PMID:16663415

  9. A Transport Analysis of In Situ Airborne Ozone Measurements from the 2011 DISCOVER-AQ Campaign

    NASA Astrophysics Data System (ADS)

    Arkinson, H. L.; Brent, L. C.; He, H.; Loughner, C.; Stehr, J. W.; Weinheimer, A. J.; Dickerson, R. R.

    2013-12-01

    Baltimore and Washington are currently designated as nonattainment areas with respect to the 2008 EPA National Ambient Air Quality Standard (NAAQS) for 8-hour Ozone (O3). Tropospheric O3 is the dominant component of summertime photochemical smog, and at high levels, has deleterious effects on human health, ecosystems, and materials. The University of Maryland (UMD) Regional Atmospheric Measurement Modeling and Prediction Program (RAMMPP) strives to improve understanding of air quality in the Mid-Atlantic States and to elucidate contributions of pollutants such as O3 from regional transport versus local sources through a combination of modeling and in situ measurements. The NASA Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) project investigates the connection between column measurements and surface conditions to explore the potential of remote sensing observations in diagnosing air quality at ground level where pollutants can affect human health. During the 2011 DISCOVER-AQ field campaign, in situ airborne measurements of trace gases and aerosols were performed along the Interstate 95 corridor between Baltimore and Washington from the NASA P3B aircraft. To augment this data and provide regional context, measurements of trace gases and aerosols were also performed by the RAMMPP Cessna 402B aircraft over nearby airports in Maryland and Virginia. This work presents an analysis of O3 measurements made by the Ultraviolet (UV) Photometric Ambient O3 Analyzer on the RAMMPP Cessna 402B and by the NCAR 4-Channel Chemiluminescence instrument on the NASA P3B. In this analysis, spatial and temporal patterns of O3 data are examined within the context of forward and backward trajectories calculated from 12-km North American Mesoscale (NAM) meteorological data using the NOAA Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) Model and from a high resolution Weather Research and

  10. In Situ Measurements of Spectral Emissivity of Materials for Very High Temperature Reactors

    SciTech Connect

    G. Cao; S. J. Weber; S. O. Martin; T. L. Malaney; S. R. Slattery; M. H. Anderson; K. Sridharan; T. R. Allen

    2011-08-01

    An experimental facility for in situ measurements of high-temperature spectral emissivity of materials in environments of interest to the gas-cooled very high temperature reactor (VHTR) has been developed. The facility is capable of measuring emissivities of seven materials in a single experiment, thereby enhancing the accuracy in measurements due to even minor systemic variations in temperatures and environments. The system consists of a cylindrical silicon carbide (SiC) block with seven sample cavities and a deep blackbody cavity, a detailed optical system, and a Fourier transform infrared spectrometer. The reliability of the facility has been confirmed by comparing measured spectral emissivities of SiC, boron nitride, and alumina (Al2O3) at 600 C against those reported in literature. The spectral emissivities of two candidate alloys for VHTR, INCONEL{reg_sign} alloy 617 (INCONEL is a registered trademark of the Special Metals Corporation group of companies) and SA508 steel, in air environment at 700 C were measured.

  11. Martian Chronology and Atmospheric Composition: In Situ Measurements versus Sample Return

    NASA Technical Reports Server (NTRS)

    Bogard, Donald D.

    2008-01-01

    I examine two significant issues of martian science from the point of view of in situ measurements by robotic spacecraft versus sample return and analysis in terrestrial labs. (1) To define martian history, ages of geological processes and surface features are required. Estimated ages from surface crater densities have limitations, and the ages measured for martian meteorites cannot be associated with specific martian locales. Whereas returned martian rocks could be accurately dated, some have suggested sending a robotic spacecraft to Mars to measure rock ages using the classical K- Ar-40 technique, considered the easiest to implement. (2) To understand the evolution of the martian atmosphere and its interactions with the surface, requires precise measurements of atmospheric composition. A significant amount of information has derived from measurements by Viking and of martian meteorites. Instrumentation on the Mars Science Lander (MSL) spacecraft to be launched in the near future promises to determine atmospheric composition even more precisely. If MSL is successful, which questions about atmospheric composition will remain and thus will require atmospheric sample return to answer?

  12. In situ measurement of low-Z material coating thickness on high Z substrate for tokamaks.

    PubMed

    Mueller, D; Roquemore, A L; Jaworski, M; Skinner, C H; Miller, J; Creely, A; Raman, P; Ruzic, D

    2014-11-01

    Rutherford backscattering of energetic particles can be used to determine the thickness of a coating of a low-Z material over a heavier substrate. Simulations indicate that 5 MeV alpha particles from an (241)Am source can be used to measure the thickness of a Li coating on Mo tiles between 0.5 and 15 μm thick. Using a 0.1 mCi source, a thickness measurement can be accomplished in 2 h of counting. This technique could be used to measure any thin, low-Z material coating (up to 1 mg/cm(2) thick) on a high-Z substrate, such as Be on W, B on Mo, or Li on Mo. By inserting a source and detector on a moveable probe, this technique could be used to provide an in situ measurement of the thickness of Li coating on NSTX-U Mo tiles. A test stand with an alpha source and an annular solid-state detector was used to investigate the measurable range of low-Z material thicknesses on Mo tiles.

  13. In-situ turbulence measurement technique using state-of-the-art kite/blimp platforms

    NASA Astrophysics Data System (ADS)

    Balsley, Ben B.; Jensen, Michael L.; Frehlich, Rod G.; Eaton, Frank D.; Bishop, Kenneth P.; Hugo, Ronald J.

    1999-08-01

    Results of a campaign to measure boundary layer/lower troposphere turbulence quantities over New Mexico's Tularosa basin are described in a companion paper. The present contribution outlines the technical developments that enabled these measurements. Basically, instrumented 'payloads' were carried aloft using either a relatively large aerodynamic blimp or a large parafoil kite. The choice between these platforms was dictated by wind velocity. The kite size was determined by the payload weight and the wind velocity. In addition to providing a brief history in CU involvement in kite/blimp atmospheric measurements, we will outline launching methods, tether winching techniques, and payload attachment schemes that were used during the WSMR campaign. Although very low wind conditions during the New Mexico test precluded the use of payloads up and down the kite tether under reasonable wind conditions. We also describe (1) the instrument package designed to measure in- situ temperature and velocity fluctuations, and (2) the 'basic payload' that measures standard atmospheric variables. System operation is illustrated via examples of the resulting data set.

  14. MEMS needle-type sensor array for in situ measurements of dissolved oxygen and redox potential.

    PubMed

    Lee, Jin-Hwan; Seo, Youngwoo; Lim, Tae-Sun; Bishop, Paul L; Papautsky, Ian

    2007-11-15

    Microelectrodes are among the most accurate and reliable monitoring devices for measuring the dynamics of biofilm processes. This paper describes a novel needle-type microelectrode array (MEA) for simultaneous in situ measurements of dissolved oxygen (DO) and oxidation reduction potential (ORP) fabricated using microelectromechanical systems (MEMS) technologies. The MEA exhibits fast response times for both DO and ORP measurements and shows a substantial increase in DO sensitivity. To demonstrate the versatility of the new sensor, it was applied to the measurement of DO and ORP microprofiles in a multispecies biofilm. This work demonstrates that the MEA is able to monitor local concentration changes with a high spatial resolution and provide the versatility of the microelectrode technique needed for biofilm studies as well as the capability for repetitive measurements. In addition, the use of MEMS technologies and batch fabrication approaches enables integration, high consistency, high yields, and mass production. With further development, it may be possible to add additional sensors to the MEA (e.g., pH, phosphate) and integrate them with a reference electrode. PMID:18075099

  15. In situ measurement of low-Z material coating thickness on high Z substrate for tokamaks

    SciTech Connect

    Mueller, D. Roquemore, A. L.; Jaworski, M.; Skinner, C. H.; Miller, J.; Creely, A.; Raman, P.; Ruzic, D.

    2014-11-15

    Rutherford backscattering of energetic particles can be used to determine the thickness of a coating of a low-Z material over a heavier substrate. Simulations indicate that 5 MeV alpha particles from an {sup 241}Am source can be used to measure the thickness of a Li coating on Mo tiles between 0.5 and 15 μm thick. Using a 0.1 mCi source, a thickness measurement can be accomplished in 2 h of counting. This technique could be used to measure any thin, low-Z material coating (up to 1 mg/cm{sup 2} thick) on a high-Z substrate, such as Be on W, B on Mo, or Li on Mo. By inserting a source and detector on a moveable probe, this technique could be used to provide an in situ measurement of the thickness of Li coating on NSTX-U Mo tiles. A test stand with an alpha source and an annular solid-state detector was used to investigate the measurable range of low-Z material thicknesses on Mo tiles.

  16. In situ Gas Measurements in Five Experimental Waste Rock Piles, Antamina Mine, Peru

    NASA Astrophysics Data System (ADS)

    Singurindy, O.; Blackmore, S. R.; Wild, A.; Mayer, K. U.; Beckie, R. D.; Smith, L.

    2009-12-01

    At the Antamina mine (Peru), a skarn deposit consisting of a quartz-monzonite porphyry hosted in limestone is mined for copper, zinc, lead, and molybdenum. Five (5) experimental waste rock piles were constructed at Antamina and instrumented to evaluate processes controlling metal release under neutral-pH drainage conditions. The piles were built over a 3-year period and each contains approximately 25,000 tonnes of waste rock classified as ‘slightly reactive’ (Pile 1 -2007), ‘reactive’ (Pile 2 and 3 - 2008), or a combination of rock of variable reactivity (Pile 4 and 5 - 2009). All waste rock, reactive to non-reactive, contains variable amounts of sulphide and carbonate minerals. Oxidation of sulphide minerals consumes O2 and generates low-pH conditions, which promotes carbonate dissolution and elevates CO2 concentrations. Sampling of the piles’ 64 in situ gas lines, using a portable gas analyzing system, revealed numerous CO2-enriched and O2-depleted zones. Piles constructed of the most reactive and fine-grained rock (Pile 2 and 3) show the highest CO¬2 concentrations (≥ 20,000 ppm), with Piles 1, 4 and 5 showing lower maximum concentrations of 1,600 ppm, 1,100 ppm, 2,900 ppm, respectively. The highest CO2 concentrations are located in the interior and near the bottom of the piles. Of the gas lines sampled from Pile 2 and 3, 88% and 95%, respectively are CO2-enriched (defined as > 2 x ambient values). The younger and less reactive piles (Pile 4 and 5) show CO2-enriched values in 3% and 17% of gas lines measured. The exothermic reaction of sulphide oxidation is also monitored by 12 in situ thermistors. Pile 2 and 3 temperatures are the highest at 9 - 10 oC. These temperatures are significantly warmer than ambient conditions (i.e., ~ 6 oC, June average) and correlate well with pockets of high CO2 concentrations. The gradational decline of CO2 concentrations with depth supports the notion that gas transport is dominated by vertical movement, while

  17. Properties of in situ made MgB2 in Nb or Ti sheath

    NASA Astrophysics Data System (ADS)

    Kováč, P.; Hušek, I.; Kopera, L.; Melišek, T.; Rosová, A.; Dobročka, E.

    2013-02-01

    Pure Nb and Ti have been used as sheath materials for MgB2 wires examined experimentally. The reason for this research is to compare the effects of these metallic sheaths on the basic properties of MgB2 superconductor. Single-core SiC doped MgB2 wires with Nb and/or Ti sheaths have been made by a powder-in-tube in situ process. Different transport currents, phase compositions and grain connectivity were observed for Nb- and Ti sheathed MgB2 heat treated at temperatures 650-850 °C/30 min. It was found that the critical current density of MgB2/Nb annealed above 700 °C rapidly decreases, while Jc of MgB2/Ti is systematically increasing with temperature. This is explained by the positive role of Ti absorbing impurities from the MgB2 core and by the negative effect of boron diffusion into Nb, reducing the quantity and worsening the quality of the MgB2 core. The obtained results show clearly that a Ti sheath offers the application of higher heat treatment temperatures (above 700 °C) and consequently the achievement of higher critical current densities in comparison to MgB2/Nb.

  18. Properties of visual cells in the lateral eye of Limulus in situ: intracellular recordings

    PubMed Central

    1977-01-01

    Two types of potential fluctuations, large and small, recorded intracellularly from photoreceptors in the dark-adapted Limulus eye in situ underlie the dual properties of the impulse discharge of the optic nerve fibers. The small potential fluctuations (SPFs)--the well-known quantum bumps--were normally less than 20 mV in amplitude. The large potential fluctuations (LPFs) were up to 80 mV in amplitude. LPFs appear to be regenerative events triggered by SPFs that enable single photon absorptions in retinular cells to fire off nerve impulses in the eccentric cell. In the dark, SPFs and LPFs occur spontaneously. At low light intensities, LPFs are the major components of the receptor potential. At high intensities, LPFs are suppressed and SPFs become the major components. SPFs and LPFs together enable single photoreceptor cells to encode approximately a 9-log unit range of light intensity. Excising the eye from the animal or cutting off its blood supply generally abolishes LPFs and thereby reduces the range of light intensity coded in the optic nerve discharge. PMID:839197

  19. Structural characterization and solution properties of a galacturonate polysaccharide derived from Aloe vera capable of in situ gelation.

    PubMed

    McConaughy, Shawn D; Stroud, Paul A; Boudreaux, Brent; Hester, Roger D; McCormick, Charles L

    2008-02-01

    A series of highly purified galacturonate polysaccharides have been extracted from the Aloe vera plant and analyzed in terms of chemical composition and molecular weight. This Aloe vera polysaccharide (AvP) has been found to exist as a high molecular weight species and possess a unique chemical composition, including a high galacturonic acid (GalA) content and low degree of methyl ester substitution. These factors facilitate gel formation upon exposure to low concentrations of calcium ions, leading to potential application in formulations designed for in situ nasal or subcutaneous protein delivery. Thorough examination of classic dilute solution properties, the [eta]-M(w), and R(g)-M(w) relationships, persistence length (L(p)), and inherent chain stiffness (B parameter), indicate an expanded random coil in aqueous salt solutions. The critical concentration for transition from dilute to concentrated solution, C(e), was determined by measuring both the zero shear viscosity (eta(o)) and fluorescence emission of the probe molecule 1,8-anilino-1-naphthalene sulfonic acid (1,8-ANS) as a function of polymer concentration. Examination of zeta potential and C(e) as a function of ionic strength indicates that the shift in C(e) from 0.60 to 0.30 wt % is related to an increased occurrence of intermolecular interactions at high salt concentrations. Additionally, dynamic rheology data are presented highlighting the ability of AvP to form gels at low polymer and calcium ion concentrations, exemplifying the technological potential of this polysaccharide for in situ drug delivery.

  20. A miniature laser ablation mass spectrometer for in situ elemental and isotopic composition measurements of planetary rocks and soils

    NASA Astrophysics Data System (ADS)

    Neuland, M. B.; Mezger, K.; Riedo, A.; Tulej, M.; Wurz, P.

    2014-04-01

    A miniature laser ablation mass spectrometer (LMS) is presented. The LMS is designed as a flight instrument for planetary and space research and optimised for in situ measurements of the chemical composition of rocks and soils on a planetary surface. By means of measurements of standard reference materials, minerals and a sample of the Allende meteorite it is demonstrated that LMS is an suitable instrument for in situ measurements of elemental and isotopic composition with high precision and accuracy. Furthermore, it is shown that LMS data allows a derivation of the material mineralogy, petrology with high spatial resolution.

  1. The Probing In-Situ With Neutron and Gamma Rays (PING) Instrument for Planetary Composition Measurements

    NASA Technical Reports Server (NTRS)

    Parsons, A.; Bodnarik, J.; Evans, L.; McClanahan, T.; Namkung, M.; Nowicki, S.; Schweitzer, J.; Starr, R.

    2012-01-01

    The Probing In situ with Neutrons and Gamma rays (PING) instrument (formerly named PNG-GRAND) [I] experiment is an innovative application of the active neutron-gamma ray technology successfully used in oil field well logging and mineral exploration on Earth over many decades. The objective of our active neutron-gamma ray technology program at NASA Goddard Space Flight Center (NASA/GSFC) is to bring PING to the point where it can be flown on a variety of surface lander or rover missions to the Moon, Mars, Venus, asteroids, comets and the satellites of the outer planets and measure their bulk surface and subsurface elemental composition without the need to drill into the surface. Gamma-Ray Spectrometers (GRS) have been incorporated into numerous orbital planetary science missions. While orbital measurements can map a planet, they have low spatial and elemental sensitivity due to the low surface gamma ray emission rates reSUlting from using cosmic rays as an excitation source, PING overcomes this limitation in situ by incorporating a powerful neutron excitation source that permits significantly higher elemental sensitivity elemental composition measurements. PING combines a 14 MeV deuterium-tritium Pulsed Neutron Generator (PNG) with a gamma ray spectrometer and two neutron detectors to produce a landed instrument that can determine the elemental composition of a planet down to 30 - 50 cm below the planet's surface, The penetrating nature of .5 - 10 MeV gamma rays and 14 MeV neutrons allows such sub-surface composition measurements to be made without the need to drill into or otherwise disturb the planetary surface, thus greatly simplifying the lander design, We are cun'ently testing a PING prototype at a unique outdoor neutron instrumentation test facility at NASA/GSFC that provides two large (1.8 m x 1.8 m x ,9 m) granite and basalt test formations placed outdoors in an empty field, Since an independent trace elemental analysis has been performed on both these

  2. In-situ measurement of the temporal evolution of the thermal conductivity of alpine snow layers

    NASA Astrophysics Data System (ADS)

    Morin, S.; Domine, F.; Arnaud, L.; Picard, G.; Jacobi, H.; Willemet, J.

    2009-12-01

    We report on a 3-months long time series of in-situ measurements of the thermal conductivity (kT) of snow in 6 different layers in an alpine snowpack in the Mont-Blanc moutain range, France, at an altitude of 2400 m. Automatic measurements were carried out every two days using the heated-needle probe technique. Results show consistent patterns of thermal conductivity increase throughout the measurements campaign. The temporal rate of change of kTvaries up to 0.01 W m-1 K-1 dy-1, with maximum values just after snowfall. Temporal rates of kTincrease are compared with results from laboratory experiments under controlled conditions and with published theoretical assessments. A case where kT decreased over time in a given snow layer was documented both in the field and in the laboratory. Possible reasons for such a behaviour are discussed. A cursory comparison of the field measured kTvalues with the prediction of the snowpack model CROCUS shows that at first order the model performs satisfactorily. However, a quantitative understanding and modeling of the variations of kT over time would require an in-depth assessment of physical processes occurring during snow metamorphism.

  3. In situ measurement of fixed charge evolution at silicon surfaces during atomic layer deposition

    SciTech Connect

    Ju, Ling; Watt, Morgan R.; Strandwitz, Nicholas C.

    2015-02-09

    Interfacial fixed charge or interfacial dipoles are present at many semiconductor-dielectric interfaces and have important effects upon device behavior, yet the chemical origins of these electrostatic phenomena are not fully understood. We report the measurement of changes in Si channel conduction in situ during atomic layer deposition (ALD) of aluminum oxide using trimethylaluminum and water to probe changes in surface electrostatics. Current-voltage data were acquired continually before, during, and after the self-limiting chemical reactions that result in film growth. Our measurements indicated an increase in conductance on p-type samples with p{sup +} ohmic contacts and a decrease in conductance on analogous n-type samples. Further, p{sup +} contacted samples with n-type channels exhibited an increase in measured current and n{sup +} contacted p-type samples exhibited a decrease in current under applied voltage. Device physics simulations, where a fixed surface charge was parameterized on the channel surface, connect the surface charge to changes in current-voltage behavior. The simulations and analogous analytical relationships for near-surface conductance were used to explain the experimental results. Specifically, the changes in current-voltage behavior can be attributed to the formation of a fixed negative charge or the modification of a surface dipole upon chemisorption of trimethylaluminum. These measurements allow for the observation of fixed charge or dipole formation during ALD and provide further insight into the electrostatic behavior at semiconductor-dielectric interfaces during film nucleation.

  4. In-situ roundness measurement and correction for pin journals in oscillating grinding machines

    NASA Astrophysics Data System (ADS)

    Yu, Hongxiang; Xu, Mengchen; Zhao, Jie

    2015-01-01

    In the mass production of vehicle-engine crankshafts, pin chasing grinding using oscillating grinding machines is a widely accepted method to achieve flexible and efficient performance. However, the eccentric movement of pin journals makes it difficult to develop an in-process roundness measurement scheme for the improvement of contour precision. Here, a new in-situ roundness measurement strategy is proposed with high scanning speed. The measuring mechanism is composed of a V-block and an adaptive telescopic support. The swing pattern of the telescopic support and the V-block is analysed for an equal angle-interval signal sampling. Hence roundness error signal is extracted in frequency domain using a small-signal model of the V-block roundness measurement method and the Fast Fourier Transformation. To implement the roundness data in the CNC coordinate system of an oscillating grinding machine, a transformation function is derived according to the motion model of pin chasing grinding methodology. Computer simulation reveals the relationship between the rotational position of the crankshaft component and the scanning angle of the displacement probe on the V-block, as well as the influence introduced by the rotation centre drift. Prototype investigation indicates the validity of the theoretical analysis and the feasibility of the new strategy.

  5. Monitoring compliance with sulfur content regulations of shipping fuel by in situ measurements of ship emissions

    NASA Astrophysics Data System (ADS)

    Kattner, L.; Mathieu-Üffing, B.; Burrows, J. P.; Richter, A.; Schmolke, S.; Seyler, A.; Wittrock, F.

    2015-09-01

    In 1997 the International Maritime Organisation (IMO) adopted MARPOL Annex VI to prevent air pollution by shipping emissions. It regulates, among other issues, the sulfur content in shipping fuels, which is transformed into the air pollutant sulfur dioxide (SO2) during combustion. Within designated Sulfur Emission Control Areas (SECA), the sulfur content was limited to 1 %, and on 1 January 2015, this limit was further reduced to 0.1 %. Here we present the set-up and measurement results of a permanent ship emission monitoring site near Hamburg harbour in the North Sea SECA. Trace gas measurements are conducted with in situ instruments and a data set from September 2014 to January 2015 is presented. By combining measurements of carbon dioxide (CO2) and SO2 with ship position data, it is possible to deduce the sulfur fuel content of individual ships passing the measurement station, thus facilitating the monitoring of compliance of ships with the IMO regulations. While compliance is almost 100 % for the 2014 data, it decreases only very little in 2015 to 95.4 % despite the much stricter limit. We analysed more than 1400 ship plumes in total and for months with favourable conditions, up to 40 % of all ships entering and leaving Hamburg harbour could be checked for their sulfur fuel content.

  6. HOAPS and ERA-Interim precipitation over the sea: validation against shipboard in situ measurements

    NASA Astrophysics Data System (ADS)

    Bumke, Karl; König-Langlo, Gert; Kinzel, Julian; Schröder, Marc

    2016-06-01

    The satellite-derived HOAPS (Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data) and ECMWF (European Centre for Medium-Range Weather Forecasts) ERA-Interim reanalysis data sets have been validated against in situ precipitation measurements from ship rain gauges and optical disdrometers over the open ocean by applying a statistical analysis for binary estimates. For this purpose collocated pairs of data were merged within a certain temporal and spatial threshold into single events, according to the satellites' overpass, the observation and the ERA-Interim times. HOAPS detects the frequency of precipitation well, while ERA-Interim strongly overestimates it, especially in the tropics and subtropics. Although precipitation rates are difficult to compare because along-track point measurements are collocated with areal estimates and the number of available data are limited, we find that HOAPS underestimates precipitation rates, while ERA-Interim's Atlantic-wide average precipitation rate is close to measurements. However, when regionally averaged over latitudinal belts, deviations between the observed mean precipitation rates and ERA-Interim exist. The most obvious ERA-Interim feature is an overestimation of precipitation in the area of the intertropical convergence zone and the southern subtropics over the Atlantic Ocean. For a limited number of snow measurements by optical disdrometers, it can be concluded that both HOAPS and ERA-Interim are suitable for detecting the occurrence of solid precipitation.

  7. in situ Measures of LED Installations: Results of Air and Ground Surveys

    NASA Astrophysics Data System (ADS)

    Craine, Eric Richard; Craine, Brian L.

    2015-08-01

    Light Emitting Diode (LED) outdoor light fixtures of different types are rapidly proliferating in many communities, particularly in the form of continuous roadway, work, and parking lot lights. These lights offer a wide range of benefits, but many in the astronomical community have expressed various concerns about their impact on local observatory facilities. We have spent several years developing complementary ground-based and aerial techniques of measuring light installations in the field. Unfortunately, large community retrofits of lighting preclude comprehensive measurement of the changes that result unless baseline data have been collected prior to completion of the new installations. Because of the rapidity of conversion to LEDs, it is increasingly difficult to conduct informative before and after surveys. As a point of interest to astronomers, we offer examples of some in situ measurements of LED installations, compare those measurements to results for older light fixtures, and discuss some of the implications for astronomy. These objective data may be helpful in reaching an informed perspective on how LED lights perform in typical settings.

  8. Experimental reslts from the HERO project: In situ measurements of ionospheric modifications using sounding rockets

    SciTech Connect

    Rose, G.; Grandal, B.; Neske, E.; Ott, W.; Spenner, K.; Maseide, K.; Troim, J.

    1985-03-01

    The Heating Rocket project HERO comprised the first in situ experiments to measure artifical ionospheric modifications at F layer heights set up by radio waves transmitted from the Heating facility at Ramfjord near Tromso in Northern Norway. Four instrumented payloads were launched on sounding rockets from Andoya Rocket Range during the autumn of 1982 into a sunlit ionosphere with the sun close to the horizon. The payloads recorded modifications, in particular, the presence of electron plasma waves near the reflection level of the heating wave. The amplitude and phase of the three components of the electric and magnetic fields of the heating wave were measured simultaneously as a function of altitude. Coherent spectra of the three electric field components of the locally generated electron plasma waves were obtained in a 50-kHz-wide band. At the same time quasi-continuous measurements were made on several fixed frequencies from 4 kHz to 16 kHz below the heating frequency and in the VLF-range using linear dipole antennas. Moreover, measurements were made of electron temperature, suprathermal electrons and local electron density along the rocket trajectory. The experimental results will be presented and discussed.

  9. Development of an in situ method to define the rheological properties of slurries and sludges stored in underground tanks

    SciTech Connect

    Heath, W.O.

    1987-04-01

    A method for measuring the in situ flow properties of high-level radioactive waste (HLW) sludges has been developed at Pacific Northwest Laboratory, along with a preconceptual design for a shear vane device that can be installed in underground HLW storage tanks and used to make those measurements remotely. The data obtained with this device will assist in the design of mixing equipment used to resuspend and remove HLW sludges from their storage tanks for downstream processing. This method is also suitable for remotely characterizing other types of waste sludges and slurries. Commonly available viscometric methods were adapted to allow characterization of sludge samples in the laboratory such that the laboratory and in-tank data can be directly compared (scaled up). Procedures for conducting measurements and analyzing the results in terms of useful mathematical models describing both start-up and steady-state flow behavior are presented, as is a brief tutorial on the types of flow behavior that can be exhibited by tank sludges. 30 refs., 36 figs., 14 tabs.

  10. Deriving seasonal dynamics in ecosystem properties of semi-arid savannas using in situ based hyperspectral reflectance

    NASA Astrophysics Data System (ADS)

    Tagesson, T.; Fensholt, R.; Huber, S.; Horion, S.; Guiro, I.; Ehammer, A.; Ardö, J.

    2015-02-01

    This paper investigates how seasonal hyperspectral reflectance data (between 350 and 1800 nm) can be used to infer ecosystem properties for a semi-arid savanna ecosystem in West Africa using a unique in situ based dataset. Relationships between seasonal dynamics in hyperspectral reflectance, and ecosystem properties (biomass, gross primary productivity (GPP), light use efficiency (LUE), and fraction of photosynthetically active radiation absorbed by vegetation (FAPAR)) were analysed. Reflectance data (ρ) were used to study the relationship between normalised difference spectral indices (NDSI) and the measured ecosystem properties. Finally, also the effects of variable sun sensor viewing geometry on different NDSI wavelength combinations were analysed. The wavelengths with the strongest correlation to seasonal dynamics in ecosystem properties were shortwave infrared (biomass), the peak absorption band for chlorophyll a and b (at 682 nm) (GPP), the oxygen A-band at 761 nm used for estimating chlorophyll fluorescence (GPP, and LUE), and blue wavelengths (FAPAR). The NDSI with the strongest correlation to: (i) biomass combined red edge reflectance (ρ705) with green reflectance (ρ587), (ii) GPP combined wavelengths at the peak of green reflection (ρ518, ρ556), (iii) the LUE combined red (ρ688) with blue reflectance (ρ436), and (iv) FAPAR combined blue (ρ399) and near infrared (ρ1295) wavelengths. NDSI combining near infrared and shortwave infrared were strongly affected by solar zenith angles and sensor viewing geometry, as were many combinations of visible wavelengths. This study provides analyses based upon novel multi-angular hyperspectral data for validation of Earth Observation based properties of semi-arid ecosystems, as well as insights for designing spectral characteristics of future sensors for ecosystem monitoring.

  11. Galileo in-situ dust measurements in Jupiter’s gossamer rings

    NASA Astrophysics Data System (ADS)

    Krüger, Harald; Hamilton, Douglas P.; Moissl, Richard; Grün, Eberhard

    2009-09-01

    Galileo was the first artificial satellite to orbit Jupiter. During its late orbital mission the spacecraft made two passages through the giant planet's gossamer ring system. The impact-ionization dust detector on board successfully recorded dust impacts during both ring passages and provided the first in-situ measurements from a dusty planetary ring. During the first passage—on 5 November 2002 while Galileo was approaching Jupiter—dust measurements were collected until a spacecraft anomaly at 2.33 RJ (Jupiter radii) just 16 min after a close flyby of Amalthea put the spacecraft into a safing mode. The second ring passage on 21 September 2003 provided ring dust measurements down to about 2.5 RJ and the Galileo spacecraft was destroyed shortly thereafter in a planned impact with Jupiter. In all, a few thousand dust impacts were counted with the instrument accumulators during both ring passages, but only a total of 110 complete data sets of dust impacts were transmitted to Earth. Detected particle sizes range from about 0.2 to 5 μm, extending the known size distribution by an order of magnitude towards smaller particles than previously derived from optical imaging [Showalter, M.R., de Pater, I., Verbanac, G., Hamilton, D.P., Burns, J.A., 2008. Icarus 195, 361-377; de Pater, I., Showalter, M.R., Macintosh, B., 2008. Icarus 195, 348-360]. The grain size distribution increases towards smaller particles and shows an excess of these tiny motes in the Amalthea gossamer ring compared to the Thebe ring. The size distribution for the Amalthea ring derived from our in-situ measurements for the small grains agrees very well with the one obtained from images for large grains. Our analysis shows that particles contributing most to the optical cross-section are about 5 μm in radius, in agreement with imaging results. The measurements indicate a large drop in particle flux immediately interior to Thebe's orbit and some detected particles seem to be on highly-tilted orbits

  12. In Situ Airborne Measurement of Formaldehyde with a New Laser Induced Fluorescence Instrument

    NASA Astrophysics Data System (ADS)

    Arkinson, H.; Hanisco, T. F.; Cazorla, M.; Fried, A.; Walega, J.

    2012-12-01

    Formaldehyde (HCHO) is a highly reactive and ubiquitous compound in the atmosphere that originates from primary emissions and secondary formation by photochemical oxidation of volatile organic compounds. HCHO is an important precursor to the formation of ozone and an ideal tracer for the transport of boundary layer pollutants to higher altitudes. In situ measurements of HCHO are needed to improve understanding of convective transport mechanisms and the effects of lofted pollutants on ozone production and cloud microphysics in the upper troposphere. The Deep Convective Clouds and Chemistry Project (DC3) field campaign addressed the effects of deep, midlatitude continental convective clouds on the upper troposphere by examining vertical transport of fresh emissions and water aloft and by characterizing subsequent changes in composition and chemistry. Observations targeting convective storms were conducted over Colorado, Alabama, and Texas and Oklahoma. We present measurements of the In Situ Airborne Formaldehyde instrument (ISAF), which uses laser induced fluorescence to achieve the high sensitivity and fast time response required to detect low concentrations in the upper troposphere and capture the fine structure characteristic of convective storm outflow. Preliminary results from DC3 indicate that the ISAF is able to resolve concentrations ranging from under 35 ppt to over 35 ppb, spanning three orders of magnitude, in less than a few minutes. Frequent, abrupt changes in HCHO captured by the ISAF are corroborated by similar patterns observed by simultaneous trace gas and aerosol measurements. Primary HCHO emissions are apparent in cases when the DC-8 flew over combustion sources or biomass burning, and secondary HCHO formation is suggested by observations of enhanced HCHO concurrent with other elevated hydrocarbons. Vertical transport of HCHO is indicated by measurements of over 6 ppb from outflow in the upper troposphere. The DC-8 payload also included the

  13. In-situ measurements of seismic velocities in the San Francisco Bay Region; part III

    USGS Publications Warehouse

    Gibbs, James F.; Fumal, Thomas E.; Borcherdt, Roger D.; Roth, Edward F.

    1977-01-01

    Seismic wave velocities (compressional and shear) are important parameters for estimating the seismic response characteristics of various geologic units when subjected to strong earthquake ground shaking. Seismic velocities of various units often show a strong correlation with the amounts of damage following large earthquakes and have been used as a basis for certain types of seismic zonation studies. In the current program seismic velocities have been measured at 59 locations 1n the San Francisco Bay Region. This report is the third in a series of Open-File Reports and describes the in-situ velocity measurements at locations 35-59. At each location seismic travel times are measured in drill holes, normally at 2.5-m intervals to a depth of 30 m. Geologic logs are determined from drill cuttings, undisturbed (cored) samples, and penetrometer samples. The data provide a detailed comparison of geologic and seismic characteristics and provide parameters for estimating strong earthquake ground motions quantitatively at each of the sites. A major emphasis of this program is to obtain a detailed comparison of geologic and seismic data on a regional scale for use in seismic zonation. There is a variety of geologic and seismic data available in the San Francisco Bay Region for use 1n developing the general zoning techniques which can then be applied to other areas. Shear wave velocities 1n near-surface geologic materials are of especial interest for engineering seismology and seismic zonation studies, yet in general, they are difficult to measure because of contamination by compressional waves. A comparison of various in-situ techniques by Warrick (1974) establishes the reliability of the method utilizing a "horizontal traction" source for sites underlain by bay mud and alluvium. Gibbs, and others (1975a) present data from 12 holes and establishes the reliability of the method for sites underlain by a variety of different rock units and suggest extending the measurements to

  14. Effect of cargo properties on in situ forming implant behavior determined by noninvasive ultrasound imaging

    PubMed Central

    Solorio, Luis; Olear, Alexander M.; Zhou, Haoyan; Beiswenger, Ashlei C.; Exner, Agata A.

    2012-01-01

    Diagnostic ultrasound has been shown to be an effective method for the noninvasive characterization of in situ forming implant behavior both in vivo and in vitro through the evaluation of the echogenic signal that forms as a consequence of the polymer phase transition from liquid to solid. The kinetics of this phase transition have a direct effect on drug release and can be altered through factors that change the mass transfer events of the solvent and aqueous environment, including properties of the entrapped active agent. This study examined the effect of payload properties on implant phase inversion, swelling, drug release, and polymer degradation. Poly(DL-lactide-co-gylcolide) implants were loaded with either: sodium fluorescein, bovine serum albumin (BSA), doxorubicin (Dox), or 1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (DiI). Fluorescein and Dox were released at near equivalent rates throughout the diffusion phase of release but due to differing drug–matrix interactions, Dox-loaded implants released a lower mass of drug during the degradation phase of release. DiI was not readily released, and due to increased depot hydrophobicity, resulted in significantly lower swelling than the other formulations. The initial echogenicity was higher in Dox-loaded implants than those loaded with fluorescein, but after the initial precipitation, phase inversion and drug release occurred at near equivalent rates for both Dox and fluorescein-loaded implants. Nonlinear mathematical fitting was used to correlate drug release and phase inversion, providing a noninvasive method for evaluating implant release (R2>0.97 for Dox, BSA, and fluorescein; DiI had a correlation coefficient of 0.56). PMID:22712054

  15. In situ measurements of X-ray peak profile asymmetry from individual grains

    NASA Astrophysics Data System (ADS)

    Wejdemann, C.; Lienert, U.; Pantleon, W.

    2010-07-01

    Two copper samples, pre-deformed in tension to 5% plastic strain, are subjected to an in situ tensile deformation of 1% plastic strain while X-ray peak profiles from individual bulk grains are obtained. One sample is oriented with the in situ tensile axis parallel to the pre-deformation axis, and peak profiles are obtained with the scattering vector parallel to this direction. The profiles show the expected asymmetry explained by the composite model as caused by intra-grain stresses. The other sample is oriented with the in situ tensile axis perpendicular to the pre-deformation axis, and peak profiles are obtained with the scattering vector parallel to the in situ tensile axis. In this case the profiles initially show an opposite asymmetry, but during the in situ deformation the asymmetry reverses sign as the deformation under new loading conditions leads to changes in the intra-grain stresses.

  16. In situ measurements of x-ray peak profile asymmetry from individual grains.

    SciTech Connect

    Wejdemann, C.; Lienert, U.; Pantleon, W.; X-Ray Science Division; Univ. of Denmark

    2010-01-01

    Two copper samples, pre-deformed in tension to 5% plastic strain, are subjected to an in situ tensile deformation of 1% plastic strain while X-ray peak profiles from individual bulk grains are obtained. One sample is oriented with the in situ tensile axis parallel to the pre-deformation axis, and peak profiles are obtained with the scattering vector parallel to this direction. The profiles show the expected asymmetry explained by the composite model as caused by intra-grain stresses. The other sample is oriented with the in situ tensile axis perpendicular to the pre-deformation axis, and peak profiles are obtained with the scattering vector parallel to the in situ tensile axis. In this case the profiles initially show an opposite asymmetry, but during the in situ deformation the asymmetry reverses sign as the deformation under new loading conditions leads to changes in the intra-grain stresses.

  17. FORTRAN programs for computation of optical properties of the sea from radiation data collected by in situ spectrometers

    NASA Astrophysics Data System (ADS)

    Sathe, P. V.; Sathyendranath, Shubha

    Measurement of spectral composition of the radiation field pervading above and below the seasurface is gaining increasing importance in recent years. It plays a significant role in ocean remote sensing to determine the constituents of seawater. An accurate description of the radiation field inside the waterbody also holds the key to solving problems of radiation transfer in the ocean. This paper presents computer programs in FORTRAN 77 which process the radiation data collected in the sea by in situ spectrometers, apply the necessary corrections to them and compute optical properties of the sea at spectral intervals of 4 nm each, within the entire visible region of electromagnetic spectrum. The programs compute the solar zenith and azimuth angles at a given location in the sea from astronomical considerations for use in computing the optical properties. The programs are useful in computing the spectral quality of upwelling light emerging out from within the sea, which forms the basic signal in remote sensing of ocean color. They also may be used by marine biologists to compute the vertical diffuse attenuation coefficients and absorption coefficients for different water types in studies on marine productivity requiring the amount of energy available for photosynthesis in different optical channels at different depths in the sea.

  18. In-situ Eh sensor measurement and calibration: application to seafloor observatories

    NASA Astrophysics Data System (ADS)

    Ding, K.; Seyfried, W. E.; Tan, C.

    2013-12-01

    Eh measurement is often used with manned submersible and AUV assets as an effective way to detect and locate seafloor hydrothermal activity. Eh can be fundamentally and sensitively linked to dissolved H 2 , which, in turn, serves as a key constraint on subseafloor redox reactions. Moreover, Eh is now being increasingly relied on for event detection and process monitoring efforts intrinsic to cabled seafloor observatories. Due to seawater interaction with electrochemical components fundamental to the operation of the Eh sensor, however, the quality and reliability of the measurements are often compromised by signal drift, especially when the sensor is used for long term deployment. To solve this problem, a calibration protocol was developed and added to our previously constructed pH 'calibrator'. Thus, the integrated electrochemical system now permits the combined in-situ measurement and calibration of pH and Eh of seafloor hydrothermal fluids. Key aspects of the design for this calibration system are: (1) the sensing electrodes can be kept preserved in fluid of known pH, Eh and NaCl concentration prior to use, thereby preventing deterioration of electrode response characteristics by chemical and biological activity; (2) the system consists of valves and pumps for flow control, and therefore can be operated remotely with power from the seafloor cabled observatory, or as a stand-alone device, using battery power for shorter-term deployments. In both cases, standardization with on-board fluids of known redox, pH, and NaCl activity can be activated at any time, providing enhanced reliability (3) the current development is aimed at deep sea environments, cold seeps, and hydrothermal diffuse flow fluids at the temperatures up to 100°C and depths up to 4500 m. The in-situ operation is especially well-suited for use with cabled observatory for real time intervention and event response owing to enabled power supply and two way communications. Field tests have been

  19. Acousto-optic Imaging System for In-situ Measurement of the High Temperature Distribution in Micron-size Specimens

    NASA Astrophysics Data System (ADS)

    Machikhin, Alexander S.; Zinin, Pavel V.; Shurygin, Alexander V.

    We developed a unique acousto-optic imaging system for in-situ measurement of high temperature distribution on micron-size specimens. The system was designed to measure temperature distribution inside minerals and functional material phases subjected to high pressure and high temperatures in a diamond anvil cell (DAC) heated by a high powered laser.

  20. Multiply scattered aerosol lidar returns: inversion method and comparison with in situ measurements.

    PubMed

    Bissonnette, L R; Hutt, D L

    1995-10-20

    A novel aerosol lidar inversion method based on the use of multiple-scattering contributions measured by a multiple-field-of-view receiver is proposed. The method requires assumptions that restrict applications to aerosol particles large enough to give rise to measurable multiple scattering and depends on parameters that must be specified empirically but that have an uncertainty range of much less than the boundary value and the backscatter-to-extinction ratio of the conventional single-scattering inversion methods. The proposed method is applied to cloud measurements. The solutions obtained are the profiles of the scattering coefficient and the effective diameter of the cloud droplets. With mild assumptions on the form of the function, the full-size distribution is estimated at each range position from which the extinction coefficient at any visible and infrared wavelength and the liquid water content can be determined. Typical results on slant-path-integrated optical depth, vertical extinction profiles, and fluctuation statistics are compared with in situ data obtained in two field experiments. The inversion works well in all cases reported here, i.e., for water clouds at optical depths between ~0.1 and ~4.

  1. Measurement of in-situ stress in salt and rock using NQR techniques

    SciTech Connect

    Schempp, E.; Hirschfeld, T.; Klainer, S.

    1980-12-01

    A discussion of how stress and strain affect the quantities which can be measured in an NQR experiment shows that, for stresses of the magnitude to be expected at depths up to about 10,000 feet, quadrupole coupling constants will fall in the range of 1 to 10 kHz for both the sodium and chloride ions in NaCl. The most promising system involves pulsed nuclear double resonance detection; and alterative is to observe the quadrupolar splitting of the NMR signal. Choices to be made in the measurement and mapping techniques are discussed. The well-known perturbation of the homogenous stress field in the neighborhood of a borehole is shown to be advantageous from the point of view of obtaining directional information on the stress. Construction and operation of a borehole stress sensor are considered. The NQR technique seems feasible for measuring the magnitude and direction of underground stress with a resolution of about 25 psi, or 2.5% at 1000 psi. Downhole instrumentation suitable for in-situ determinations of stress appears within the state of the art. Additional tasks required on the project are identified.

  2. Regular, Fast and Accurate Airborne In-Situ Methane Measurements Around the Tropopause

    NASA Astrophysics Data System (ADS)

    Dyroff, Christoph; Rauthe-Schöch, Armin; Schuck, Tanja J.; Zahn, Andreas

    2013-04-01

    We present a laser spectrometer for automated monthly measurements of methane (CH4) mixing ratios aboard the CARIBIC passenger aircraft. The instrument is based on a commercial fast methane analyzer (FMA, Los Gatos Res.), which was modified for fully unattended employment. A laboratory characterization was performed and the results with emphasis on the precision, cross sensitivity to H2O, and accuracy are presented. An in-flight calibration strategy is described, that utilizes CH4 measurements obtained from flask samples taken during the same flights. By statistical comparison of the in-situ measurements with the flask samples we derive a total uncetrainty estimate of ~ 3.85 ppbv (1?) around the tropopause, and ~ 12.4 ppbv (1?) during aircraft ascent and descent. Data from the first two years of airborne operation are presented that span a large part of the northern hemispheric upper troposphere and lowermost stratosphere, with occasional crossings of the tropics on flights to southern Africa. With its high spatial resolution and high accuracy this data set is unprecedented in the highly important atmospheric layer of the tropopause.

  3. Fast repetition rate (FRR) fluorometer for making in situ measurements of primary productivity

    SciTech Connect

    Kolber, Z.S.; Falkowski, P.G.

    1992-01-01

    Understanding the ocean carbon cycle and predicting how climate-induced changes in ocean circulation will affect ocean productivity requires that (a) primary productivity be measured with high spatial and temporal resolution, and (b) natural variability in primary productivity be parameterized with regardto environmental factors such as nutrient availabuity, irradiance, and temperature. Instrumentation to measure primary productivity from the stimulated in vivo fluoresence of phytoplankton chlorophyll is currendy being developed at Brookhaven National Laboratory. The instrumentation is based on fast repetition rate (FRR) fluorometry, and provides a robust technique for deriving the photosynthetic rates in situ. Moreover, the FRR methodology directly measures several photosynthetic parameters such as effective absorption cross- section, photo-conversion efficiency, and turnover time of photosynthesis, and relate them to primary productivity. Since photosynthetic parameters are affected by environmental factors such as fight and nutrient availability, the relationship between these parameters and primary productivity can be established. By understanding such relationships, prognostic models of primary productivity can be developed and parameterized.

  4. Fast repetition rate (FRR) fluorometer for making in situ measurements of primary productivity

    SciTech Connect

    Kolber, Z.S.; Falkowski, P.G.

    1992-10-01

    Understanding the ocean carbon cycle and predicting how climate-induced changes in ocean circulation will affect ocean productivity requires that (a) primary productivity be measured with high spatial and temporal resolution, and (b) natural variability in primary productivity be parameterized with regardto environmental factors such as nutrient availabuity, irradiance, and temperature. Instrumentation to measure primary productivity from the stimulated in vivo fluoresence of phytoplankton chlorophyll is currendy being developed at Brookhaven National Laboratory. The instrumentation is based on fast repetition rate (FRR) fluorometry, and provides a robust technique for deriving the photosynthetic rates in situ. Moreover, the FRR methodology directly measures several photosynthetic parameters such as effective absorption cross- section, photo-conversion efficiency, and turnover time of photosynthesis, and relate them to primary productivity. Since photosynthetic parameters are affected by environmental factors such as fight and nutrient availability, the relationship between these parameters and primary productivity can be established. By understanding such relationships, prognostic models of primary productivity can be developed and parameterized.

  5. In-Situ Measurement of Vertical Bypass Flow Using a Drain Gauge

    NASA Astrophysics Data System (ADS)

    Payne, W. L.; Brooks, E. S.; Sanchez-Murillo, R.

    2012-12-01

    With widespread technological advances in precision fertilizer application in agricultural production there is an increasing need to better understand the subsurface transport and vertical leaching of nitrate fertilizers. Optimizing fertilizer application reduces cost to the grower and improves downstream water supplies. In-situ measurement of nitrate flux is difficult and expensive. In this experiment nitrate transport was measured using a passive capillary drain gauge developed by Decagon Devices in Pullman, WA. The drain gauge measures water flux from a 30 cm diameter soil core 60 cm in length. In this study the drain gauge was installed 0.9 m to 1.5 m below the soil surface in a no-till field in cereal grain production. A potassium bromide tracer was applied using a rainfall simulator over a 5 day period to the drain gage roughly one year following installation of the drain gauge and approximately 3 months after being seeded to spring wheat. Bromide tracer movement was compared to measurements of stable oxygen/hydrogen isotopes, and nitrate in the leachate and from soil water extracted within the soil profile using suction lysimeters. Significant preferential flow occurred during the experiment. Vertical leaching initiated at the 1.5 m depth at a time when the wetting front had just reached the 0.3 cm depth. By the time the wetting front had reached a 1.5 m depth, 18 kg/ha of nitrogen fertilizer had leached beyond the root zone. Once the wetting front reached 1.5 m bromide and stable isotope data indicated that 60% of the total flow occurred through macropore flow. Stable isotope measurements responded similarly to the electrical conductivity and nitrate measurements suggesting their potential use as a groundwater tracer. The nitrate leaching observed in the drain gauge would not have been accounted for if soil moisture measurements alone were used to indicate potential nitrate transport.

  6. Comparison of different methods for the in situ measurement of forest litter moisture content

    NASA Astrophysics Data System (ADS)

    Schunk, C.; Ruth, B.; Leuchner, M.; Wastl, C.; Menzel, A.

    2016-02-01

    Dead fine fuel (e.g., litter) moisture content is an important parameter for both forest fire and ecological applications as it is related to ignitability, fire behavior and soil respiration. Real-time availability of this value would thus be a great benefit to fire risk management and prevention. However, the comprehensive literature review in this paper shows that there is no easy-to-use method for automated measurements available. This study investigates the applicability of four different sensor types (permittivity and electrical resistance measuring principles) for this measurement. Comparisons were made to manual gravimetric reference measurements carried out almost daily for one fire season and overall agreement was good (highly significant correlations with 0.792 < = r < = 0.947, p < 0.001). Standard deviations within sensor types were linearly correlated to daily sensor mean values; however, above a certain threshold they became irregular, which may be linked to exceedance of the working ranges. Thus, measurements with irregular standard deviations were considered unusable and relationships between gravimetric and automatic measurements of all individual sensors were compared only for useable periods. A large drift in these relationships became obvious from drought to drought period. This drift may be related to installation effects or settling and decomposition of the litter layer throughout the fire season. Because of the drift and the in situ calibration necessary, it cannot be recommended to use the methods presented here for monitoring purposes and thus operational hazard management. However, they may be interesting for scientific studies when some manual fuel moisture measurements are made anyway. Additionally, a number of potential methodological improvements are suggested.

  7. In situ membrane resistance measurements in polymer electrolyte fuel cells by fast auxiliary current pulses

    SciTech Connect

    Buechi, F.N.; Scherer, G.G.; Marek, A.

    1995-06-01

    A solid-state current Pulse generator for in situ membrane resistance measurements by superimposed square current pulses in polymer electrolyte fuel cells was designed and built. The choice of the measuring technique and of parameters of the instrumentation was based on a critical analysis of the relevant electrochemical and physical processes. The inductance of the current pulse path is very low ({approx}5 nH), because the last stage of the generator is directly attached to the fuel cell. This low inductance -permits the generation of 5 A pulses with extremely fast (decay time {<=}5 ns) trailing edges (accompanied by a moderate ringing), which in turn makes it possible to measure the voltage transient induced by the current decay, with gigahertz resolution. The voltage transient is analyzed in a time window of 200 to 700 ns after the end of the pulse. By measurements in this time window, it is possible to separate accurately the ohmic series resistance of the cell (membrane resistance) from the other over potentials at the electrochemical interfaces. Because the pulse current path is independent of the dc loop, the resistance can be measured independently of the dc value, i.e., at open circuit and under high current density conditions. The instrument was tested, and the results were analyzed for accuracy. Resistances down to 2 m{Omega} can be measured with an error of <5%. The influence of the pulse length and pulse amplitude on the cell voltage response was also investigated. For cell resistances in the order of few milliohms, a current pulse amplitude of 5 A is the minimum requirement for accurate measurements.

  8. Determining Phosphorus-sediment Interactions in a Groundwater-fed River through In Situ Measurement

    NASA Astrophysics Data System (ADS)

    Mullinger, N. J.; Heathwaite, L.; Zhang, H.; Keenan, P. O.

    2011-12-01

    In stream processing is potentially important in the regulation and availability of nutrients to riverine flora and also in attenuating point and non-point source inputs to rivers, such as wastewater outflows and agricultural runoff. Phosphorus is an important macronutrient and often cited as a limiting factor to plant and algal growth in freshwater systems. The particle-reactive nature of the orthophosphate anion means that river sediments can play an important role in phosphorus attenuation and availability in rivers. However, it is also known that plant root exudates can also affect the mobilisation of sediment adsorbed phosphorus. Results are presented from high resolution (centimetre) measurements of vertical riverbed pore water profiles at a field site in the River Leith, Cumbria, UK. The River Leith is a sub-catchment of the River Eden and is characterised by significant groundwater-surface water interactions at the monitoring site. In situ measurements of soluble reactive phosphorus (SRP) in riverbed pore waters were made using passive sampling diffusive gradient and diffusive equilibration in thin film (DGT and DET) probes. These probes allow in situ measurements of riverbed pore waters to be made to a depth of 30 cm below the riverbed at centimetre resolution. The resulting profiles provide information on the variability in phosphorus pore waters for vegetated and non-vegetated regions of the riverbed. The impact of vegetated root zones in riverbed sediments is poorly characterised for hyporheic exchanges. Comparison of the vertical profiles obtained by DGT and DET probes identifies the potential of sediments to act sources or sinks of in stream phosphorus. Simultaneous analysis for redox sensitive elements provides additional information on the redox status of riverbed sediments. Initial results show spatial and temporal variability of phosphorus in different sedimentary environments and also between vegetated and non-vegetated areas of the riverbed

  9. In-situ measurement of dissolved H 2 in aqueous fluid at elevated temperatures and pressures

    NASA Astrophysics Data System (ADS)

    Ding, K.; Seyfried, W. E., Jr.

    1995-11-01

    In-situ measurement of Hz in aqueous fluid under hydrothermal conditions has long been a major concern in experimental geochemistry owing to the important role of H 2 in a wide range of homogenous and heterogeneous equilibria. Although numerous efforts have been made, an effective and reliable H 2 sensor for geochemical applications is lacking, especially one suitable for measurement at supercritical conditions of water. In this paper, we discuss a sensor which was developed for in-situ measurement of dissolved H 2 in aqueous fluid at temperatures and pressures greater than previously possible. In general, the H 2 sensor consists of two electrodes and a Hg/HgO internal reference element: a platinum electrode and a yttrium-stabilized zirconia (YSZ) membrane electrode. The electrochemical cell can be depicted as follows: Pt|H 2, H +, H 2O|ZrO 2(Y 2O 3)| HgO|Hg. A titanium flow reactor was used to test and calibrate sensor response and sensitivity. Dissolved H 2 concentration and the rate of fluid flowing through the reactor were controlled by a modified HPLC pump and computer system, respectively. Dissolved H 2 concentrations of fluid leaving the reactor were determined by GC analysis. ΔE YH of the fluid in the reactor was, at the same time, monitored and recorded by an electrometer with high input impedance. The experiments were performed at 400 bars, and temperatures up to 400°C. Results revealed good Nemstain response, even for unusually low dissolved H 2 concentrations. Thus, at 400°C and 400 bars, the following calibration line was obtained: Δ EYH (V) = 0.972 + 0.054 log mH 2 (M/kg) ( r = 0.9974, N = 9), where mH 2 ranged from 0.096 to 5.75 mM/kg. The experiments also demonstrated excellent stability of the sensor during the month-long operation. The high temperature H 2 sensor may have important applications for field monitoring dissolved H 2 in mid-ocean ridge vent fluids. It is also ideally suited for direct determination of redox state in hydrothermal

  10. Measurement and analysis of sarcomere length in rat cardiomyocytes in situ and in vitro

    PubMed Central

    Camelliti, P.; Bollensdorff, C.; Stuckey, D. J.; Picton, G.; Burton, R. A. B.; Clarke, K.; Kohl, P.

    2010-01-01

    Sarcomere length (SL) is an important determinant and indicator of cardiac mechanical function; however, techniques for measuring SL in living, intact tissue are limited. Here, we present a technique that uses two-photon microscopy to directly image striations of living cells in cardioplegic conditions, both in situ (Langendorff-perfused rat hearts and ventricular tissue slices, stained with the fluorescent marker di-4-ANEPPS) and in vitro (acutely isolated rat ventricular myocytes). Software was developed to extract SL from two-photon fluorescence image sets while accounting for measurement errors associated with motion artifact in raster-scanned images and uncertainty of the cell angle relative to the imaging plane. Monte-Carlo simulations were used to guide analysis of SL measurements by determining error bounds as a function of measurement path length. The mode of the distribution of SL measurements in resting Langendorff-perfused heart is 1.95 μm (n = 167 measurements from N = 11 hearts) after correction for tissue orientation, which was significantly greater than that in isolated cells (1.71 μm, n = 346, N = 9 isolations) or ventricular slice preparations (1.79 μm, n = 79, N = 3 hearts) under our experimental conditions. Furthermore, we find that edema in arrested Langendorff-perfused heart is associated with a mean SL increase; this occurs as a function of time ex vivo and correlates with tissue volume changes determined by magnetic resonance imaging. Our results highlight that the proposed method can be used to monitor SL in living cells and that different experimental models from the same species may display significantly different SL values under otherwise compar