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Sample records for force base ca

  1. Weather Research and Forecasting Model Wind Sensitivity Study at Edwards Air Force Base, CA

    NASA Technical Reports Server (NTRS)

    Watson, Leela R.; Bauman, William H., III; Hoeth, Brian

    2009-01-01

    This abstract describes work that will be done by the Applied Meteorology Unit (AMU) in assessing the success of different model configurations in predicting "wind cycling" cases at Edwards Air Force Base, CA (EAFB), in which the wind speeds and directions oscillate among towers near the EAFB runway. The Weather Research and Forecasting (WRF) model allows users to choose among two dynamical cores - the Advanced Research WRF (ARW) and the Non-hydrostatic Mesoscale Model (NMM). There are also data assimilation analysis packages available for the initialization of the WRF model - the Local Analysis and Prediction System (LAPS) and the Advanced Regional Prediction System (ARPS) Data Analysis System (ADAS). Having a series of initialization options and WRF cores, as well as many options within each core, creates challenges for local forecasters, such as determining which configuration options are best to address specific forecast concerns. The goal of this project is to assess the different configurations available and determine which configuration will best predict surface wind speed and direction at EAFB.

  2. CloudSat Preps for Launch at Vandenberg Air Force Base, CA

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The CloudSat spacecraft sits encapsulated within its Boeing Delta launch vehicle dual payload attach fitting at Vandenberg Air Force Base, Calif. CloudSat will share its ride to orbit late next month with NASA's CALIPSO spacecraft. The two spacecraft are designed to reveal the secrets of clouds and aerosols.

  3. 10. "TEST STAND 15, AIR FORCE FLIGHT TEST CENTER." ca. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. "TEST STAND 1-5, AIR FORCE FLIGHT TEST CENTER." ca. 1958. Test Area 1-115. Original is a color print, showing Test Stand 1-5 from below, also showing the superstructure of TS1-4 at left. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Leuhman Ridge near Highways 58 & 395, Boron, Kern County, CA

  4. Statistical Short-Range Guidance for Peak Wind Speed Forecasts at Edwards Air Force Base, CA

    NASA Technical Reports Server (NTRS)

    Dreher, Joseph G.; Crawford, Winifred; Lafosse, Richard; Hoeth, Brian; Burns, Kerry

    2009-01-01

    The peak winds near the surface are an important forecast element for space shuttle landings. As defined in the Flight Rules (FR), there are peak wind thresholds that cannot be exceeded in order to ensure the safety of the shuttle during landing operations. The National Weather Service Spaceflight Meteorology Group (SMG) is responsible for weather forecasts for all shuttle landings, and is required to issue surface average and 10-minute peak wind speed forecasts. They indicate peak winds are a challenging parameter to forecast. To alleviate the difficulty in making such wind forecasts, the Applied Meteorology Unit (AMU) developed a PC-based graphical user interface (GUI) for displaying peak wind climatology and probabilities of exceeding peak wind thresholds for the Shuttle Landing Facility (SLF) at Kennedy Space Center (KSC; Lambert 2003). However, the shuttle occasionally may land at Edwards Air Force Base (EAFB) in southern California when weather conditions at KSC in Florida are not acceptable, so SMG forecasters requested a similar tool be developed for EAFB.

  5. Weather Research and Forecasting Model Wind Sensitivity Study at Edwards Air Force Base, CA

    NASA Technical Reports Server (NTRS)

    Watson, Leela R.; Bauman, William H., III

    2008-01-01

    NASA prefers to land the space shuttle at Kennedy Space Center (KSC). When weather conditions violate Flight Rules at KSC, NASA will usually divert the shuttle landing to Edwards Air Force Base (EAFB) in Southern California. But forecasting surface winds at EAFB is a challenge for the Spaceflight Meteorology Group (SMG) forecasters due to the complex terrain that surrounds EAFB, One particular phenomena identified by SMG is that makes it difficult to forecast the EAFB surface winds is called "wind cycling". This occurs when wind speeds and directions oscillate among towers near the EAFB runway leading to a challenging deorbit bum forecast for shuttle landings. The large-scale numerical weather prediction models cannot properly resolve the wind field due to their coarse horizontal resolutions, so a properly tuned high-resolution mesoscale model is needed. The Weather Research and Forecasting (WRF) model meets this requirement. The AMU assessed the different WRF model options to determine which configuration best predicted surface wind speed and direction at EAFB, To do so, the AMU compared the WRF model performance using two hot start initializations with the Advanced Research WRF and Non-hydrostatic Mesoscale Model dynamical cores and compared model performance while varying the physics options.

  6. Statistical Short-Range Guidance for Peak Wind Speed Forecasts at Edwards Air Force Base, CA

    NASA Technical Reports Server (NTRS)

    Dreher, Joseph; Crawford, Winifred; Lafosse, Richard; Hoeth, Brian; Burns, Kerry

    2008-01-01

    The peak winds near the surface are an important forecast element for Space Shuttle landings. As defined in the Shuttle Flight Rules (FRs), there are peak wind thresholds that cannot be exceeded in order to ensure the safety of the shuttle during landing operations. The National Weather Service Spaceflight Meteorology Group (SMG) is responsible for weather forecasts for all shuttle landings. They indicate peak winds are a challenging parameter to forecast. To alleviate the difficulty in making such wind forecasts, the Applied Meteorology Unit (AMTJ) developed a personal computer based graphical user interface (GUI) for displaying peak wind climatology and probabilities of exceeding peak-wind thresholds for the Shuttle Landing Facility (SLF) at Kennedy Space Center. However, the shuttle must land at Edwards Air Force Base (EAFB) in southern California when weather conditions at Kennedy Space Center in Florida are not acceptable, so SMG forecasters requested that a similar tool be developed for EAFB. Marshall Space Flight Center (MSFC) personnel archived and performed quality control of 2-minute average and 10-minute peak wind speeds at each tower adjacent to the main runway at EAFB from 1997- 2004. They calculated wind climatologies and probabilities of average peak wind occurrence based on the average speed. The climatologies were calculated for each tower and month, and were stratified by hour, direction, and direction/hour. For the probabilities of peak wind occurrence, MSFC calculated empirical and modeled probabilities of meeting or exceeding specific 10-minute peak wind speeds using probability density functions. The AMU obtained and reformatted the data into Microsoft Excel PivotTables, which allows users to display different values with point-click-drag techniques. The GUT was then created from the PivotTables using Visual Basic for Applications code. The GUI is run through a macro within Microsoft Excel and allows forecasters to quickly display and

  7. 3. SOUTH SIDE. Edwards Air Force Base, South Base ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. SOUTH SIDE. - Edwards Air Force Base, South Base Sled Track, Firing & Control Blockhouse for 10,000-foot Track, South of Sled Track at midpoint of 20,000-foot track, Lancaster, Los Angeles County, CA

  8. Methods for Manipulating CaF Using Optical Polychromatic Forces

    NASA Astrophysics Data System (ADS)

    Eyler, Edward E.; Galica, Scott E.; Aldridge, Leland M.

    2013-06-01

    We are undertaking theoretical and experimental studies of laser deceleration and cooling of molecules using coherent multi-frequency optical forces. A primary objective is to reduce radiative loss into dark states when a pure two-level cycling transition is unavailable. The optical bichromatic force (BCF) can multiply the available velocity change for a given number of radiative cycles, by employing alternating cycles of excitation and stimulated emission from opposing directions. Tests in atomic helium show that when the BCF is combined with frequency chirping, very large decelerations are achieved. We report numerical studies of variations intended to further optimize deceleration, including a 4-color version. We describe progress on experimental tests using the 531 nm B ^2Σ^+leftrightarrow X ^2Σ^+ transition in CaF. We also describe low-cost lasers and electronics developed for these experiments. Several versatile new instruments are based on 32-bit microcontrollers, interfaced to an Android tablet that provides a touch-screen graphical interface. These include a timing/ramp generator, a PZT driver, a temperature controller, and even a phase-synchronized dual 35-4000 MHz rf synthesizer that fits on a 2 1/4" × 4 3/4" board. This research is supported by the National Science Foundation. M.A. Chieda and E.E. Eyler, Phys. Rev. A 86, 053415 (2012); also Phys. Rev. A 84, 063401 (2011).

  9. Automated analysis of contractile force and Ca2+ transients in engineered heart tissue.

    PubMed

    Stoehr, Andrea; Neuber, Christiane; Baldauf, Christina; Vollert, Ingra; Friedrich, Felix W; Flenner, Frederik; Carrier, Lucie; Eder, Alexandra; Schaaf, Sebastian; Hirt, Marc N; Aksehirlioglu, Bülent; Tong, Carl W; Moretti, Alessandra; Eschenhagen, Thomas; Hansen, Arne

    2014-05-01

    Contraction and relaxation are fundamental aspects of cardiomyocyte functional biology. They reflect the response of the contractile machinery to the systolic increase and diastolic decrease of the cytoplasmic Ca(2+) concentration. The analysis of contractile function and Ca(2+) transients is therefore important to discriminate between myofilament responsiveness and changes in Ca(2+) homeostasis. This article describes an automated technology to perform sequential analysis of contractile force and Ca(2+) transients in up to 11 strip-format, fibrin-based rat, mouse, and human fura-2-loaded engineered heart tissues (EHTs) under perfusion and electrical stimulation. Measurements in EHTs under increasing concentrations of extracellular Ca(2+) and responses to isoprenaline and carbachol demonstrate that EHTs recapitulate basic principles of heart tissue functional biology. Ca(2+) concentration-response curves in rat, mouse, and human EHTs indicated different maximal twitch forces (0.22, 0.05, and 0.08 mN in rat, mouse, and human, respectively; P < 0.001) and different sensitivity to external Ca(2+) (EC50: 0.15, 0.39, and 1.05 mM Ca(2+) in rat, mouse, and human, respectively; P < 0.001) in the three groups. In contrast, no difference in myofilament Ca(2+) sensitivity was detected between skinned rat and human EHTs, suggesting that the difference in sensitivity to external Ca(2+) concentration is due to changes in Ca(2+) handling proteins. Finally, this study confirms that fura-2 has Ca(2+) buffering effects and is thereby changing the force response to extracellular Ca(2+). PMID:24585781

  10. Automated analysis of contractile force and Ca2+ transients in engineered heart tissue

    PubMed Central

    Stoehr, Andrea; Neuber, Christiane; Baldauf, Christina; Vollert, Ingra; Friedrich, Felix W.; Flenner, Frederik; Carrier, Lucie; Eder, Alexandra; Schaaf, Sebastian; Hirt, Marc N.; Aksehirlioglu, Bülent; Tong, Carl W.; Moretti, Alessandra; Eschenhagen, Thomas

    2014-01-01

    Contraction and relaxation are fundamental aspects of cardiomyocyte functional biology. They reflect the response of the contractile machinery to the systolic increase and diastolic decrease of the cytoplasmic Ca2+ concentration. The analysis of contractile function and Ca2+ transients is therefore important to discriminate between myofilament responsiveness and changes in Ca2+ homeostasis. This article describes an automated technology to perform sequential analysis of contractile force and Ca2+ transients in up to 11 strip-format, fibrin-based rat, mouse, and human fura-2-loaded engineered heart tissues (EHTs) under perfusion and electrical stimulation. Measurements in EHTs under increasing concentrations of extracellular Ca2+ and responses to isoprenaline and carbachol demonstrate that EHTs recapitulate basic principles of heart tissue functional biology. Ca2+ concentration-response curves in rat, mouse, and human EHTs indicated different maximal twitch forces (0.22, 0.05, and 0.08 mN in rat, mouse, and human, respectively; P < 0.001) and different sensitivity to external Ca2+ (EC50: 0.15, 0.39, and 1.05 mM Ca2+ in rat, mouse, and human, respectively; P < 0.001) in the three groups. In contrast, no difference in myofilament Ca2+ sensitivity was detected between skinned rat and human EHTs, suggesting that the difference in sensitivity to external Ca2+ concentration is due to changes in Ca2+ handling proteins. Finally, this study confirms that fura-2 has Ca2+ buffering effects and is thereby changing the force response to extracellular Ca2+. PMID:24585781

  11. Optical Bichromatic Force on CaF Molecules

    NASA Astrophysics Data System (ADS)

    Aldridge, L.; Galica, S. E.; Sheets, D.; Eyler, E. E.

    2016-05-01

    The optical bichromatic force (BCF) is a coherent optical force which can be much stronger than saturated radiative forces. BCF has been experimentally demonstrated in atomic systems and has recently drawn attention as an option for deflecting or decelerating neutral molecular beams. We have devised a realistic numerical model for calcium monofluoride (CaF), including the full 16-level hyperfine structure of two rovibrational states and magnetic-field destabilization of coherent dark states. We show that BCF illumination of this system produces a force two orders of magnitude stronger than that achieved by radiative forces, and we find that the required parameters are experimentally realistic and are robust against small variations. A simplified simulation scheme that saves computational time at little expense to accuracy is also presented. Experimental tests on the B <--> X transition in CaF are underway in our laboratory, starting with transverse deflection of a supersonic molecular beam. In collaboration with the group of John Doyle, we are also looking into BCF on the triatomic SrOH molecule. Supported by the National Science Foundation and the University of Connecticut.

  12. Public health assessment for George Air Force Base, Victorville, San Bernardino County, California, Region 9: CERCLIS Number CA2570024453. Final report

    SciTech Connect

    1998-12-01

    George Air Force Base (AFB) is located in Victorville, California, in the Mojave Desert approximately 90 miles northeast of Los Angeles. Areas of concern at George AFB are divided into three operable units (OUs): Groundwater in the northeast portion of the base and adjacent off-site land is contaminated with volatile organic compounds, primarily TCE. A groundwater extraction and treatment system, designed to prevent migration of the contaminant plume towards the Mojave River, was completed in 1997. OU 1 also includes two other sites: SD-25, an industrial/storm drain, and WP-26, the former sewage treatment plant percolation ponds. Contaminated sediments and piping were removed from the storm drain at SD-25. A variety of leaks in this system resulted in an estimated of perhaps as much as a 750,000 to 800,000-gallon plume of jet propellant no. 4 (JP-4) encompassing an area of over 31 acres, as well as a dissolved-phase plume of benzene, toluene, ethylbenzene, and xylenes extending over an area of 121 acres. Because of OU2 plumes is almost completely covered by asphalt, and studies conducted thus far have not demonstrated significant migration of the plume, George AFB, state and federal regulators continue to evaluate the feasibility of natural attenuation as a possible cleanup strategy. This OU consists of the remaining Installation Restoration Program sites, includes old landfills, other dump and burial sites, munitions sites, fire training areas, and spill areas. In February 1997, George AFB completed a remedial investigation/feasibility study for OU 3.

  13. GENERAL SITE PLAN, HAMILTON AIR FORCE BASE, MARIN COUNTY, CALIFORNIA. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    GENERAL SITE PLAN, HAMILTON AIR FORCE BASE, MARIN COUNTY, CALIFORNIA. Pencil on paper, dated December 4, 1952. Also marked "PWC 103474." By J.Y. Long Company, Engineers, Oakland, California - Hamilton Field, East of Nave Drive, Novato, Marin County, CA

  14. Interior view Beale Air Force Base, Perimeter Acquisition Vehicle ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior view - Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Satellite Communications Terminal, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

  15. Looking north Beale Air Force Base, Perimeter Acquisition Vehicle ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Looking north - Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Electric Substation, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

  16. Exterior, looking west Beale Air Force Base, Perimeter Acquisition ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Exterior, looking west - Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Civil Engineering Storage Building, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

  17. Interior, looking northwest Beale Air Force Base, Perimeter Acquisition ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior, looking northwest - Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Civil Engineering Storage Building, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

  18. Interior, looking northeast Beale Air Force Base, Perimeter Acquisition ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior, looking northeast - Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Microwave Equipment Building, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

  19. 26. "AIR INSTALLATIONS; EDWARDS AIR FORCE BASE, CALIFORNIA; HIGH SPEED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    26. "AIR INSTALLATIONS; EDWARDS AIR FORCE BASE, CALIFORNIA; HIGH SPEED TEST TRACK." Drawing No. 10-259. One inch to 400 feet plan of original 10,000-foot sled track. No date. No D.O. series number. No headings as above. - Edwards Air Force Base, South Base Sled Track, Edwards Air Force Base, North of Avenue B, between 100th & 140th Streets East, Lancaster, Los Angeles County, CA

  20. 76 FR 25548 - Safety Zone; Coast Guard Use of Force Training Exercises, San Pablo Bay, CA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-05

    ...; Coast Guard Use of Force Training Exercises, San Pablo Bay, CA in the Federal Register (74 FR 214). We... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Coast Guard Use of Force Training Exercises, San Pablo Bay, CA AGENCY: Coast Guard, DHS. ACTION: Final rule. SUMMARY: The Coast Guard...

  1. Vision-based force measurement.

    PubMed

    Greminger, Michael A; Nelson, Bradley J

    2004-03-01

    This paper demonstrates a method to visually measure the force distribution applied to a linearly elastic object using the contour data in an image. The force measurement is accomplished by making use of the result from linear elasticity that the displacement field of the contour of a linearly elastic object is sufficient to completely recover the force distribution applied to the object. This result leads naturally to a deformable template matching approach where the template is deformed according to the governing equations of linear elasticity. An energy minimization method is used to match the template to the contour data in the image. This technique of visually measuring forces we refer to as vision-based force measurement (VBFM). VBFM has the potential to increase the robustness and reliability of micromanipulation and biomanipulation tasks where force sensing is essential for success. The effectiveness of VBFM is demonstrated for both a microcantilever beam and a microgripper. A sensor resolution of less than +/- 3 nN for the microcantilever and +/- 3 mN for the microgripper was achieved using VBFM. Performance optimizations for the energy minimization problem are also discussed that make this algorithm feasible for real-time applications. PMID:15376877

  2. [Forced Oscillations of DNA Bases].

    PubMed

    Yakushevich, L V; Krasnobaeva, L A

    2016-01-01

    This paper presents the results of the studying of forced angular oscillations of the DNA bases with the help of the mathematical model consisting of two coupled nonlinear differential equations that take into account the effects of dissipation and the influence of an external periodic field. The calculation results are illustrated for sequence of gene encoding interferon alpha 17 (IFNA 17). PMID:27192830

  3. Effects of trimebutine on cytosolic Ca2+ and force transitions in intestinal smooth muscle.

    PubMed

    Nagasaki, M; Kobayashi, T; Tamaki, H

    1991-04-01

    The effects of trimebutine maleate on cytosolic free Ca2+ and force transitions in the guinea-pig taenia cecum were studied by fura-2 fluorometry and tension recording. The addition of 80 mM K+ induced a transient increase in cytosolic free Ca2+ concentration ([Ca2+]i) and tension, followed by a sustained increase. Trimebutine (10 microM) suppressed both [Ca2+]i elevation and tension development. The tonic responses were more potently inhibited than the phasic responses. Phasic components gradually increased as the added K+ increased (10-40 mM). The relationship between the peak increases in [Ca2+]i and tension was not affected by trimebutine (10 microM). This means that trimebutine does not affect the Ca2+ sensitivity of contractile elements. In a high K+ and Ca(2+)-free medium, carbachol (10 microM) or caffeine (30 mM) caused transient [Ca2+]i elevation and tension development in the smooth muscle. Trimebutine (10 microM) decreased the amplitude of both responses. Trimebutine (10 microM) inhibited the spontaneous fluctuations in [Ca2+]i and motility of taenia cecum in the presence of tetrodotoxin (TTX; 0.3 microM). These results suggest that trimebutine has two types of inhibitory actions on intestinal smooth muscle; one, the inhibition of Ca2+ influx through voltage-dependent calcium channels, and the other, the inhibition of Ca2+ release from intracellular storage sites. PMID:1868878

  4. Neutron Knockout to Probe 3N Forces in the Ca Isotopes

    NASA Astrophysics Data System (ADS)

    Crawford, Heather; NSCL Experiment e12029 Collaboration

    2013-10-01

    Recent calculations by Holt et al. have suggested that the inclusion of 3N forces to describe the structure of neutron-rich Ca isotopes provides a more realistic description of the nuclear structure. Mass measurements have confirmed the importance of including 3N forces compared to NN-only interactions, but cannot discriminate between the predictions of phenomenological interactions and the NN+3N microscopic calculations. Neutron knockout along the Z = 20 isotopes provides an opportunity to test the results of NN+3N calculations against phenomenological interactions. The calculations of Holt et al. predict a fragmentation of the 1f7 / 2 neutron strength from the first 7/2- state in 49Ca into higher lying states, in contrast to the predictions of both GXPF1 and KB3G which concentrate the strength in the lowest lying 7/2- state. Differences are also observed in the summed f7 / 2 strength to bound nuclear states in both 50Ca and 49Ca neutron knockout. We will report on a systematic study of one-neutron knockout along the Ca isotopes using GRETINA+S800. Comparison of experimental spectroscopic factors to calculations will provide insight into the role of 3N forces in describing the Z = 20 isotopes. With collaborators from LBNL, NSCL/MSU, ANL, Central Michigan University, TRIUMF/UBC and TU-Darmstadt.

  5. Force kinetics and individual sarcomere dynamics in cardiac myofibrils after rapid ca(2+) changes.

    PubMed Central

    Stehle, R; Krüger, M; Pfitzer, G

    2002-01-01

    Kinetics of force development and relaxation after rapid application and removal of Ca(2+) were measured by atomic force cantilevers on subcellular bundles of myofibrils prepared from guinea pig left ventricles. Changes in the structure of individual sarcomeres were simultaneously recorded by video microscopy. Upon Ca(2+) application, force developed with an exponential rate constant k(ACT) almost identical to k(TR), the rate constant of force redevelopment measured during steady-state Ca(2+) activation; this indicates that k(ACT) reflects isometric cross-bridge turnover kinetics. The kinetics of force relaxation after sudden Ca(2+) removal were markedly biphasic. An initial slow linear decline (rate constant k(LIN)) lasting for a time t(LIN) was abruptly followed by an ~20 times faster exponential decay (rate constant k(REL)). k(LIN) is similar to k(TR) measured at low activating [Ca(2+)], indicating that k(LIN) reflects isometric cross-bridge turnover kinetics under relaxed-like conditions (see also. Biophys. J. 83:2142-2151). Video microscopy revealed the following: invariably at t(LIN) a single sarcomere suddenly lengthened and returned to a relaxed-type structure. Originating from this sarcomere, structural relaxation propagated from one sarcomere to the next. Propagated sarcomeric relaxation, along with effects of stretch and P(i) on relaxation kinetics, supports an intersarcomeric chemomechanical coupling mechanism for rapid striated muscle relaxation in which cross-bridges conserve chemical energy by strain-induced rebinding of P(i). PMID:12324432

  6. Maximal Force Characteristics of the Ca2+-Powered Actuator of Vorticella convallaria

    PubMed Central

    Ryu, Sangjin; Lang, Matthew J.; Matsudaira, Paul

    2012-01-01

    The millisecond stalk contraction of the sessile ciliate Vorticella convallaria is powered by energy from Ca2+ binding to generate contractile forces of ∼10 nN. Its contractile organelle, the spasmoneme, generates higher contractile force under increased stall resistances. By applying viscous drag force to contracting V. convallaria in a microfluidic channel, we observed that the mechanical force and work of the spasmoneme depended on the stalk length, i.e., the maximum tension (150–350 nN) and work linearly depended on the stalk length (∼2.5 nN and ∼30 fJ per 1 μm of the stalk). This stalk-length dependency suggests that motor units of the spasmoneme may be organized in such a way that the mechanical force and work of each unit cumulate in series along the spasmoneme. PMID:23009835

  7. Utility Building Plan, elevations and sections. March Air Force Base, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Utility Building Plan, elevations and sections. March Air Force Base, Riverside, California, COmbat Operations Center, Utility Building. By Moffatt and Nichol, Engineers, 122 West Fifth Street, Long Beach, California; for the Corps of Engineers, U.S. Army, Office of the District Engineer, Los Angeles, California. Drawing no. AW-60-02-03, sheet no. 57, approved March, 1962; specifications no. ENG-04-353-62-66; D.O. series AW 1596/57, Rev. "B"; file drawer 1290. Last revised 3 October 1966 "drawings updated." Various scales. 29 x 41 inches. pencil on paper - March Air Force Base, Strategic Air Command, Utility Building, 5220 Riverside Drive, Moreno Valley, Riverside County, CA

  8. Ca2+ Changes the Force Sensitivity of the Hair-Cell Transduction Channel

    PubMed Central

    Cheung, Eunice L. M.; Corey, David P.

    2006-01-01

    The mechanically gated transduction channels of vertebrate hair cells tend to close in ∼1 ms after their activation by hair bundle deflection. This fast adaptation is correlated with a quick negative movement of the bundle (a “twitch”), which can exert force and may mediate an active mechanical amplification of sound stimuli in hearing organs. We used an optical trap to deflect bullfrog hair bundles and to measure bundle movement while controlling Ca2+ entry with a voltage clamp. The twitch elicited by repolarization of the cell varied with force applied to the bundle, going to zero where channels were all open or closed. The force dependence is quantitatively consistent with a model in which a Ca2+-bound channel requires ∼3 pN more force to open, and rules out other models for the site of Ca2+ action. In addition, we characterized a faster, voltage-dependent “flick”, which requires intact tip links but not current through transduction channels. PMID:16214875

  9. Beale Air Force Base, Perimeter Acquisition Vehicle Entry PhasedArray Warning ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Satellite Communications Terminal, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

  10. Beale Air Force Base, Perimeter Acquisition Vehicle Entry PhasedArray Warning ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Electric Substation, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

  11. Beale Air Force Base, Perimeter Acquisition Vehicle Entry PhasedArray Warning ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Civil Engineering Storage Building, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

  12. Beale Air Force Base, Perimeter Acquisition Vehicle Entry PhasedArray Warning ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Techinical Equipment Building, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

  13. Beale Air Force Base, Perimeter Acquisition Vehicle Entry PhasedArray Warning ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Microwave Equipment Building, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

  14. Cantilever based optical interfacial force microscope

    NASA Astrophysics Data System (ADS)

    Bonander, Jeremy R.; Kim, Byung I.

    2008-03-01

    We developed a cantilever based optical interfacial force microscopy (COIFM) that employs a microactuated silicon cantilever and optical detection method to establish the measurement of the single molecular interactions using the force feedback technique. Through the direct measurement of the COIFM force-distance curves, we have demonstrated that the COIFM is capable of unveiling structural and mechanical information on interfacial water at the single molecular level over all distances between two hydrophilic surfaces.

  15. The relationship between the intracellular Ca2+ transient and the isometric twitch force in frog muscle fibres.

    PubMed

    Sun, Y B; Lou, F; Edman, K A

    1996-09-01

    The calcium-sensitive fluorescent indicator fluo-3 was used to monitor the intracellular free calcium concentration ([Ca2+]i) during isometric twitches in twenty-nine single muscle fibres from the anterior tibialis muscle of Rana temporaria (sarcomere length, 2.2 microns; 2-4 degrees C). The transient change in [Ca2+]i in response to a single stimulus was very brief. The time to peak and the duration of the Ca2+ signal, measured at 50% of the peak amplitude, were 8.3 +/- 0.2 and 22.1 +/- 1.4 ms (mean +/- S.E.M., n = 29), respectively. The mean peak amplitude of the Ca2+ transient was 3.2 +/- 0.1 microM, ranging from 2.46 to 3.92 microM among the different fibres. The isometric force started to rise 2.5 ms before [Ca2+]i reached its maximum value. When peak twitch force was attained, [Ca2+]i had already declined to approximately 10% of its maximum value. The peak force produced during a twitch was closely related to the decay phase of the Ca2+ transient, a slower decay of [Ca2+]i being associated with a greater amplitude of the twitch. The amplitude and duration of the Ca2+ transient varied in a systematic way relative to one another in different fibres, in that a greater amplitude was associated with a more rapid decay of the Ca2+ transient. NO3- and Zn2+ added to the external medium greatly enhanced the peak twitch force without markedly affecting the amplitude of the Ca2+ transient. However, both agents delayed the decay of [Ca2+]i. It is concluded that the decay phase of the Ca2+ transient is a more important determinant of the mechanical response during an isometric twitch than is the peak amplitude of the transient. PMID:8889472

  16. 33 CFR 165.1184 - Safety Zone; Coast Guard Use of Force Training Exercises, San Pablo Bay, CA.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Force Training Exercises, San Pablo Bay, CA. 165.1184 Section 165.1184 Navigation and Navigable Waters... Coast Guard District § 165.1184 Safety Zone; Coast Guard Use of Force Training Exercises, San Pablo Bay.... If the exercises conclude prior to the scheduled termination time, the Coast Guard will...

  17. Velocity, force, power, and Ca2+ sensitivity of fast and slow monkey skeletal muscle fibers

    NASA Technical Reports Server (NTRS)

    Fitts, R. H.; Bodine, S. C.; Romatowski, J. G.; Widrick, J. J.

    1998-01-01

    In this study, we determined the contractile properties of single chemically skinned fibers prepared from the medial gastrocnemius (MG) and soleus (Sol) muscles of adult male rhesus monkeys and assessed the effects of the spaceflight living facility known as the experiment support primate facility (ESOP). Muscle biopsies were obtained 4 wk before and immediately after an 18-day ESOP sit, and fiber type was determined by immunohistochemical techniques. The MG slow type I fiber was significantly smaller than the MG type II, Sol type I, and Sol type II fibers. The ESOP sit caused a significant reduction in the diameter of type I and type I/II (hybrid) fibers of Sol and MG type II and hybrid fibers but no shift in fiber type distribution. Single-fiber peak force (mN and kN/m2) was similar between fiber types and was not significantly different from values previously reported for other species. The ESOP sit significantly reduced the force (mN) of Sol type I and MG type II fibers. This decline was entirely explained by the atrophy of these fiber types because the force per cross-sectional area (kN/m2) was not altered. Peak power of Sol and MG fast type II fiber was 5 and 8.5 times that of slow type I fiber, respectively. The ESOP sit reduced peak power by 25 and 18% in Sol type I and MG type II fibers, respectively, and, for the former fiber type, shifted the force-pCa relationship to the right, increasing the Ca2+ activation threshold and the free Ca2+ concentration, eliciting half-maximal activation. The ESOP sit had no effect on the maximal shortening velocity (Vo) of any fiber type. Vo of the hybrid fibers was only slightly higher than that of slow type I fibers. This result supports the hypothesis that in hybrid fibers the slow myosin heavy chain would be expected to have a disproportionately greater influence on Vo.

  18. Sections. March Air Force Base, Riverside, California, Combat Operations Center, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Sections. March Air Force Base, Riverside, California, Combat Operations Center, Combat Operations Building. By Moffatt and Nichol, Engineers, 122 West Fifth Street, Long Beach, California; for the Corps of Engineers, U.S. Army, Office of the District Engineer, Los Angeles, California. Drawing no. AW-60-02-03, sheet no. 14, approved March, 1962; specifications no. ENG-04-353-62-66; D.O. series AW 1596/15, Rev. "A"; file drawer 1290. Last revised 3 October 1966. Scale one-eighth inch to one foot. 30x36 inches. pencil on paper - March Air Force Base, Strategic Air Command, Combat Operations Center, 5220 Riverside Drive, Moreno Valley, Riverside County, CA

  19. Elevations. March Air Force Base, Riverside, California, Combat Operations Center, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Elevations. March Air Force Base, Riverside, California, Combat Operations Center, Combat Operations Building. By Moffatt and Nichol, Engineers, 122 West Fifth Street, Long Beach, California; for the Corps of Engineers, U.S. Army, Office of the District Engineer, Los Angeles, California. Drawing no. AW-60-02-03, sheet no. 14, approved March, 1962; specifications no. ENG-04-353-62-66; D.O. series AW 1596/14, Rev. "B"; file drawer 77-1/102. Last revised 3 October 1966. Scale one-eighth inch to one foot. 30x36 inches. photocopy on paper - March Air Force Base, Strategic Air Command, Combat Operations Center, 5220 Riverside Drive, Moreno Valley, Riverside County, CA

  20. Unraveling Base Stacking Driving Forces in DNA.

    PubMed

    Mak, Chi H

    2016-07-01

    Base stacking is a key determinant of nucleic acid structures, but the precise origin of the thermodynamic driving force behind the stacking of nucleobases remains open. The rather mild stacking free energy measured experimentally, roughly a kcal/mol depending on the identity of the bases, is physiologically significant because while base stacking confers stability to the genome in its double helix form, the duplex also has to be unwound in order to be replicated or transcribed. A stacking free energy that is either too high or too low will over- or understabilize the genome, impacting the storage of genetic information and also its retrieval. While the molecular origin of stacking driving force has been attributed to many different sources including dispersion, electrostatics, and solvent hydrogen bonding, here we show via a systematic decomposition of the stacking free energy using large-scale computer simulations that the dominant driving force stabilizing base stacking is nonhydrophobic solvent entropy. Counteracting this is the conformational entropic penalty on the sugar-phosphate backbone against stacking, while solvent hydrogen-bonding, charge-charge interactions, and dispersive forces produce only secondary perturbations. Solvent entropic forces and DNA backbone conformational strains therefore work against each other, leading to a very mild composite stacking free energy in agreement with experiments. PMID:27045853

  1. SOLVENT RECOVERY AT VANDENBERG AIR FORCE BASE

    EPA Science Inventory

    The report gives results of a feasibility study of the addition of vapor recovery and solvent purification equipment for Vandenberg Air Force Base (VAFB) to reuse the large quantities of waste solvent generated in space shuttle preparation operations. (NOTE: Operation of VAFB as ...

  2. Data Driven, Force Based Interaction for Quadrotors

    NASA Astrophysics Data System (ADS)

    McKinnon, Christopher D.

    Quadrotors are small and agile, and are becoming more capable for their compact size. They are expected perform a wide variety of tasks including inspection, physical interaction, and formation flight. In all of these tasks, the quadrotors can come into close proximity with infrastructure or other quadrotors, and may experience significant external forces and torques. Reacting properly in each case is essential to completing the task safely and effectively. In this thesis, we develop an algorithm, based on the Unscented Kalman Filter, to estimate such forces and torques without making assumptions about the source of the forces and torques. We then show in experiment how the proposed estimation algorithm can be used in conjunction with controls and machine learning to choose the appropriate actions in a wide variety of tasks including detecting downwash, tracking the wind induced by a fan, and detecting proximity to the wall.

  3. Keesler Air Force Base team tours Stennis

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Stennis Space Center Deputy Director Patrick Scheuermann (seated, center) welcomed members of the Keesler Air Force Base management team from Biloxi during a Nov. 4 tour of the rocket engine test facility. During the visit, Keesler team members toured several areas, including the A-3 Test Stand construction site and the Pratt & Whitney Rocketdyne engine assembly facility. Management team members visiting Stennis included Brig. Gen. Ian R. Dickinson (seated, right), commander of the Keesler base, and Col. Christopher Valle (seated, left), vice commander of the base.

  4. Store-operated Ca²⁺ entry and depolarization explain the anomalous behaviour of myometrial SR: effects of SERCA inhibition on electrical activity, Ca²⁺ and force.

    PubMed

    Noble, Debbie; Borysova, Lyudmyla; Wray, Susan; Burdyga, Theodor

    2014-09-01

    In the myometrium SR Ca(2+) depletion promotes an increase in force but unlike several other smooth muscles, there is no Ca(2+) sparks-STOCs coupling mechanism to explain this. Given the importance of the control of contractility for successful parturition, we have examined, in pregnant rat myometrium, the effects of SR Ca(2+)-ATPase (SERCA) inhibition on the temporal relationship between action potentials, Ca(2+) transients and force. Simultaneous recording of electrical activity, calcium and force showed that SERCA inhibition, by cyclopiazonic acid (CPA 20 μM), caused time-dependent changes in excitability, most noticeably depolarization and elevations of baseline [Ca(2+)]i and force. At the onset of these changes there was a prolongation of the bursts of action potentials and a corresponding series of Ca(2+) spikes, which increased the amplitude and duration of contractions. As the rise of baseline Ca(2+) and depolarization continued a point was reached when electrical and Ca(2+) spikes and phasic contractions ceased, and a maintained, tonic force and Ca(2+) was produced. Lanthanum, a non-selective blocker of store-operated Ca(2+) entry, but not the L-type Ca(2+) channel blocker nifedipine (1-10 μM), could abolish the maintained force and calcium. Application of the agonist, carbachol, produced similar effects to CPA, i.e. depolarization, elevation of force and calcium. A brief, high concentration of carbachol, to cause SR Ca(2+) depletion without eliciting receptor-operated channel opening, also produced these results. The data obtained suggest that in pregnant rats SR Ca(2+) release is coupled to marked Ca(2+) entry, via store operated Ca(2+) channels, leading to depolarization and enhanced electrical and mechanical activity. PMID:25084623

  5. Distinct mechanisms regulating mechanical force-induced Ca2+ signals at the plasma membrane and the ER in human MSCs

    PubMed Central

    Kim, Tae-Jin; Joo, Chirlmin; Seong, Jihye; Vafabakhsh, Reza; Botvinick, Elliot L; Berns, Michael W; Palmer, Amy E; Wang, Ning; Ha, Taekjip; Jakobsson, Eric; Sun, Jie; Wang, Yingxiao

    2015-01-01

    It is unclear that how subcellular organelles respond to external mechanical stimuli. Here, we investigated the molecular mechanisms by which mechanical force regulates Ca2+ signaling at endoplasmic reticulum (ER) in human mesenchymal stem cells. Without extracellular Ca2+, ER Ca2+ release is the source of intracellular Ca2+ oscillations induced by laser-tweezer-traction at the plasma membrane, providing a model to study how mechanical stimuli can be transmitted deep inside the cell body. This ER Ca2+ release upon mechanical stimulation is mediated not only by the mechanical support of cytoskeleton and actomyosin contractility, but also by mechanosensitive Ca2+ permeable channels on the plasma membrane, specifically TRPM7. However, Ca2+ influx at the plasma membrane via mechanosensitive Ca2+ permeable channels is only mediated by the passive cytoskeletal structure but not active actomyosin contractility. Thus, active actomyosin contractility is essential for the response of ER to the external mechanical stimuli, distinct from the mechanical regulation at the plasma membrane. DOI: http://dx.doi.org/10.7554/eLife.04876.001 PMID:25667984

  6. Secure electronic commerce communication system based on CA

    NASA Astrophysics Data System (ADS)

    Chen, Deyun; Zhang, Junfeng; Pei, Shujun

    2001-07-01

    In this paper, we introduce the situation of electronic commercial security, then we analyze the working process and security for SSL protocol. At last, we propose a secure electronic commerce communication system based on CA. The system provide secure services such as encryption, integer, peer authentication and non-repudiation for application layer communication software of browser clients' and web server. The system can implement automatic allocation and united management of key through setting up the CA in the network.

  7. Interaction force microscopy based on quartz tuning fork force sensor

    NASA Astrophysics Data System (ADS)

    Qin, Yexian

    The ability to sense small changes in the interaction force between a scanning probe microscope (SPM) tip and a substrate requires cantilevers with a sharp mechanical resonance. A typical commercially available cantilever in air is characterized by a resonance with a Q factor of 100 ˜ 300. The low Q factor can be attributed to imperfections in the cantilever itself as well as damping effects of the surrounding air. To substantially increase the Q factor, novel concepts are required. For this reason, we have performed a systematic study of quartz tuning fork resonators for possible use with SPMs. We find that tuning fork resonators operating in air are characterized by Q factors in the order of 104, thereby greatly improving the SPM's ability to measure small shifts in the interaction force. By carefully attaching commercially available SPM tips to the tuning fork, it is possible to obtain SPM images using non-contact imaging techniques and analyze the tip-sample interactions. The assembly of uniform molecular monolayers on atomically flat substrates for molecular electronics applications has received widespread attention during the past ten years. Scanning probe techniques are often used to assess substrate topography, molecular ordering and electronic properties, yet little is known about the fundamental tip-molecule interaction. To address this issue we have built an Interaction Force Microscope using a quartz tuning fork to probe tip-molecular monolayer interactions using scanning probe microscopy. The high quality factor and stable resonant frequency of a quartz tuning fork allows accurate measurement of small shifts in the resonant frequency as the tip interacts with the substrate. To permit an accurate measure of surface interaction forces, the electrical and piezomechanical properties of a tuning fork have been calibrated using a fiber optical interferometer. In prior work [1], we have studied molecular layers formed from either 4-Trifluoro

  8. Electrorheological Fluid Based Force Feedback Device

    NASA Technical Reports Server (NTRS)

    Pfeiffer, Charles; Bar-Cohen, Yoseph; Mavroidis, Constantinos; Dolgin, Benjamin

    1999-01-01

    Parallel to the efforts to develop fully autonomous robots, it is increasingly being realized that there are applications where it is essential to have a fully controlled robot and "feel" its operating conditions, i.e. telepresence. This trend is a result of the increasing efforts to address tasks where humans can perform significantly better but, due to associated hazards, distance, physical limitations and other causes, only robots can be employed to perform these tasks. Such robots need to be assisted by a human that remotely controls the operation. To address the goal of operating robots as human surrogates, the authors launched a study of mechanisms that provide mechanical feedback. For this purpose, electrorheological fluids (ERF) are being investigated for the potential application as miniature haptic devices. This family of electroactive fluids has the property of changing the viscosity during electrical stimulation. Consequently, ERF can be used to produce force feedback haptic devices for tele-operated control of medical and space robotic systems. Forces applied at the robot end-effector due to a compliant environment are reflected to the user using an ERF device where a change in the system viscosity will occur proportionally to the transmitted force. Analytical model and control algorithms are being developed taking into account the non-linearities of these type of devices. This paper will describe the concept and the developed mechanism of ERF based force feedback. The test process and the physical properties of this device will be described and the results of preliminary tests will be presented.

  9. The Implementation of School Based Continuous Assessment (CA) in Zambia

    ERIC Educational Resources Information Center

    Kapambwe, William M.

    2010-01-01

    In Zambia, continuous assessment (CA) is defined as an on-going, diagnostic, classroom-based process that uses a variety of assessment tools to measure learner performance (MOE, 2005:5). Over the years, examinations have been used for selection and certification, without formal considerations on school-based continuous assessment as a component in…

  10. The Driving Force of the Na+/Ca2+-Exchanger during Metabolic Inhibition

    PubMed Central

    Baartscheer, Antonius; Schumacher, Cees A.; Coronel, Ruben; Fiolet, Jan W. T.

    2011-01-01

    Objective: Metabolic inhibition causes a decline in mechanical performance and, if prolonged, myocardial contracture and cell death. The decline in mechanical performance is mainly due to altered intracellular calcium handling, which is under control of the Na+/Ca2+-exchanger (NCX) The driving force of the NCX (ΔGncx) determines the activity of NCX. The aim of this study was to describe the relation between ΔGncx and calcium homeostasis during metabolic inhibition. Methods: In left ventricular rabbit myocytes, during metabolic inhibition (2 mmol/L sodium cyanide), sodium ([Na+]i), calcium ([Ca2+;]i), and action potentials were determined with SBFI, indo-1, and the patch clamp technique. Changes of ΔGncx were calculated. Results: During metabolic inhibition: The first 8 min [Na+]i remained constant, systolic calcium decreased from 532 ± 28 to 82 ± 13 nM, diastolic calcium decreased from 121 ± 12 to 36 ± 10 nM and the sarcoplasmic reticulum (SR) calcium content was depleted for 85 ± 3%. After 8 min [Na+;]i and diastolic calcium started to increase to 30 ± 1.3 mmol/L and 500 ± 31 nM after 30 min respectively. The action potential duration shortened biphasically. In the first 5 min it shortened from 225 ± 12 to 153 ± 11 ms and remained almost constant until it shortened again after 10 min. After 14 min action potential and calcium transients disappeared due to unexcitability of the myocytes. This resulted in an increased of the time average of ΔGncx from 6.2 ± 0.2 to 7.7 ± 0.3 kJ/mol during the first 3 min, where after it decreased and became negative after about 15 min. Conclusion: Metabolic inhibition caused an early increase of ΔGncx caused by shortening of the action potential. The increase of ΔGncx contributed to decrease of diastolic calcium, calcium transient amplitude, SR calcium content, and contractility. The increase of diastolic calcium started after ΔGncx became

  11. Nanoactuators Based on Electrostatic Forces on Dielectrics

    NASA Technical Reports Server (NTRS)

    Wang, Yu

    2005-01-01

    Nanoactuators of a proposed type would exploit the forces exerted by electric fields on dielectric materials. As used here, "nanoactuators" includes motors, manipulators, and other active mechanisms that have dimensions of the order of nanometers and/or are designed to manipulate objects that have dimensions of the order of nanometers. The underlying physical principle can be described most simply in terms of the example of a square parallel-plate capacitor in which a square dielectric plate is inserted part way into the gap between the electrode plates (see Figure Typically, the force is small from our macroscopic human perspective. The above equation shows that the force depends on the ratio between the capacitor dimensions but does not depend on the size. In other words, the force remains the same if the capacitor and the dielectric slab are shrunk to nanometer dimensions. At the same time, the masses of all components are proportional to third power of their linear dimensions. Therefore the force-to-mass ratio (and, consequently, the acceleration that can be imparted to the dielectric slab) is much larger at the nanoscale than at the macroscopic scale. The proposed actuators would exploit this effect. The upper part of Figure 2 depicts a simple linear actuator based on a parallel- plate capacitor similar to Figure 1. In this case, the upper electrode plate would be split into two parts (A and B) and the dielectric slab would be slightly longer than plate A or B. The actuator would be operated in a cycle. During the first half cycle, plate B would be grounded to the lower plate and plate A would be charged to a potential, V, with respect to the lower plate, causing the dielectric slab to be pulled under plate A. During the second half cycle, plate A would be grounded and plate B would be charged to potential V, causing the dielectric slab to be pulled under plate B. The back-and-forth motion caused by alternation of the voltages on plates A and B could be used

  12. Time course changes in [Ca2+]i, force, and protein content in hindlimb-suspended mouse soleus muscles

    NASA Technical Reports Server (NTRS)

    Ingalls, C. P.; Wenke, J. C.; Armstrong, R. B.; Hamilton, S. L. (Principal Investigator)

    2001-01-01

    BACKGROUND: Exposure to reduced gravitational forces during spaceflight is associated with significant reductions in skeletal muscle mass and strength. The purpose of this study was to test the hypothesis that increases in resting cytosolic free calcium concentration ([Ca2+]i) would precede reductions in protein content and maximal isometric tetanic force (Po) in mouse soleus muscle after initiation of hindlimb suspension. METHODS: Female ICR mice (n = 42) were hindlimb suspended for 1, 2, 3, 5, or 7 d; weight-matched mice were used as controls. Following the hindlimb suspension, the left soleus muscle was used to determine Po in vitro and the right soleus muscle was used to determine protein content and [Ca2+]i via confocal laser scanning microscopy. RESULTS: Compared with controls, [Ca2+]i was elevated by 38% at 2 d, and 117% at 7 d. Compared with controls, soleus muscle total and myofibrillar protein contents were reduced 27-29% and 30-34%, respectively, at 5-7 d after initiation of hindlimb suspension. Compared with controls, soleus muscle Po was decreased by 24% at 3 d, and 38% at 7 d. CONCLUSION: It appears that resting cytosolic Ca2+ homeostasis is disturbed soon after the initiation of hindlimb suspension, and these elevations in [Ca2+]i may play a role in initiating soleus muscle atrophy.

  13. CHARMM Force-Fields with Modified Polyphosphate Parameters Allow Stable Simulation of the ATP-Bound Structure of Ca(2+)-ATPase.

    PubMed

    Komuro, Yasuaki; Re, Suyong; Kobayashi, Chigusa; Muneyuki, Eiro; Sugita, Yuji

    2014-09-01

    Adenosine triphosphate (ATP) is an indispensable energy source in cells. In a wide variety of biological phenomena like glycolysis, muscle contraction/relaxation, and active ion transport, chemical energy released from ATP hydrolysis is converted to mechanical forces to bring about large-scale conformational changes in proteins. Investigation of structure-function relationships in these proteins by molecular dynamics (MD) simulations requires modeling of ATP in solution and ATP bound to proteins with accurate force-field parameters. In this study, we derived new force-field parameters for the triphosphate moiety of ATP based on the high-precision quantum calculations of methyl triphosphate. We tested our new parameters on membrane-embedded sarcoplasmic reticulum Ca(2+)-ATPase and four soluble proteins. The ATP-bound structure of Ca(2+)-ATPase remains stable during MD simulations, contrary to the outcome in shorter simulations using original parameters. Similar results were obtained with the four ATP-bound soluble proteins. The new force-field parameters were also tested by investigating the range of conformations sampled during replica-exchange MD simulations of ATP in explicit water. Modified parameters allowed a much wider range of conformational sampling compared with the bias toward extended forms with original parameters. A diverse range of structures agrees with the broad distribution of ATP conformations in proteins deposited in the Protein Data Bank. These simulations suggest that the modified parameters will be useful in studies of ATP in solution and of the many ATP-utilizing proteins. PMID:26588553

  14. Atomic Force Microscopy Based Cell Shape Index

    NASA Astrophysics Data System (ADS)

    Adia-Nimuwa, Usienemfon; Mujdat Tiryaki, Volkan; Hartz, Steven; Xie, Kan; Ayres, Virginia

    2013-03-01

    Stellation is a measure of cell physiology and pathology for several cell groups including neural, liver and pancreatic cells. In the present work, we compare the results of a conventional two-dimensional shape index study of both atomic force microscopy (AFM) and fluorescent microscopy images with the results obtained using a new three-dimensional AFM-based shape index similar to sphericity index. The stellation of astrocytes is investigated on nanofibrillar scaffolds composed of electrospun polyamide nanofibers that has demonstrated promise for central nervous system (CNS) repair. Recent work by our group has given us the ability to clearly segment the cells from nanofibrillar scaffolds in AFM images. The clear-featured AFM images indicated that the astrocyte processes were longer than previously identified at 24h. It was furthermore shown that cell spreading could vary significantly as a function of environmental parameters, and that AFM images could record these variations. The new three-dimensional AFM-based shape index incorporates the new information: longer stellate processes and cell spreading. The support of NSF PHY-095776 is acknowledged.

  15. Simultaneous measurement of normal and friction forces using a cantilever-based optical interfacial force microscope

    NASA Astrophysics Data System (ADS)

    Kim, Byung I.; Bonander, Jeremy R.; Rasmussen, Jared A.

    2011-05-01

    We measured normal and friction forces simultaneously using a recently developed cantilever-based optical interfacial force microscope technique for studies of interfacial structures and mechanical properties of nanoscale materials. We derived how the forces can be incorporated into the detection signal using the classical Euler equation for beams. A lateral modulation with the amplitude of nanometers was applied to create the friction forces between tip and sample. We demonstrated its capability by measuring normal and friction forces of interfacial water at the molecular scale over all distance ranges.

  16. Simultaneous measurement of normal and friction forces using a cantilever-based optical interfacial force microscope.

    PubMed

    Kim, Byung I; Bonander, Jeremy R; Rasmussen, Jared A

    2011-05-01

    We measured normal and friction forces simultaneously using a recently developed cantilever-based optical interfacial force microscope technique for studies of interfacial structures and mechanical properties of nanoscale materials. We derived how the forces can be incorporated into the detection signal using the classical Euler equation for beams. A lateral modulation with the amplitude of nanometers was applied to create the friction forces between tip and sample. We demonstrated its capability by measuring normal and friction forces of interfacial water at the molecular scale over all distance ranges. PMID:21639511

  17. Lorentz Force Based Satellite Attitude Control

    NASA Astrophysics Data System (ADS)

    Giri, Dipak Kumar; Sinha, Manoranjan

    2016-07-01

    Since the inception of attitude control of a satellite, various active and passive control strategies have been developed. These include using thrusters, momentum wheels, control moment gyros and magnetic torquers. In this present work, a new technique named Lorentz force based Coulombic actuators for the active control is proposed. This method uses electrostatic charged shells, which interact with the time varying earth's magnetic field to establish a full three axes control of the satellite. It is shown that the proposed actuation mechanism is similar to a satellite actuated by magnetic coils except that the resultant magnetic moment vanishes under two different conditions. The equation for the required charges on the the Coulomb shells attached to the satellite body axes is derived, which is in turn used to find the available control torque for actuating the satellite along the orbit. Stability of the proposed system for very high initial angular velocity and exponential stability about the origin are proved for a proportional-differential control input. Simulations are carried out to show the efficacy of the proposed system for the attitude control of the earth-pointing satellite.

  18. Offutt Air Force Base, Looking Glass Airborne Command Post, Blast ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Offutt Air Force Base, Looking Glass Airborne Command Post, Blast Deflector Fences, Northeast & Southwest sides of Operational Apron, Project Looking Glass Historic District, Bellevue, Sarpy County, NE

  19. Offutt Air Force Base, Looking Glass Airborne Command Post, Operational ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Offutt Air Force Base, Looking Glass Airborne Command Post, Operational & Hangar Access Aprons, Spanning length of northeast half of Project Looking Glass Historic District, Bellevue, Sarpy County, NE

  20. Development and evaluation of materials for thermochemical heat storage based on the CaO/CaCO3 reaction couple

    NASA Astrophysics Data System (ADS)

    Sakellariou, Kyriaki G.; Tsongidis, Nikolaos I.; Karagiannakis, George; Konstandopoulos, Athanasios G.; Baciu, Diana; Charalambopoulou, Georgia; Steriotis, Theodore; Stubos, Athanasios; Arlt, Wolfgang

    2016-05-01

    The current work relates to the development of synthetic calcium oxide (CaO) based compositions as candidate materials for energy storage under a cyclic carbonation/decarbonation reaction scheme. Although under such a cyclic scheme the energy density of natural lime based CaO is high (˜ 3MJ/kg), the particular materials suffer from notable cycle-to-cycle deactivation. To this direction, pure CaO and CaO/Al2O3 composites have been prepared and preliminarily evaluated under the suggested cyclic carbonation/decarbonation scheme in the temperature range of 600-800°C. For the composite materials, Ca/Al molar ratios were in the range between 95/5 and 52/48 and upon calcination the formation of mixed Ca/Al phases was verified. The preliminary evaluation of materials studied was conducted under 3 carbonation/decarbonation cycles and the loss of activity for the case of natural CaO was obvious. Synthetic materials with superior stability/capture c.f. natural CaO were further subjected to multi-cyclic carbonation/decarbonation, via which the positive effect of alumina addition was made evident. Selected compositions exhibited adequately high CO2 capture capacity and stable performance during multi-cyclic operation. Moreover, this study contains preliminary experiments referring to proof-of-principle validation of a concept based on the utilization of a CaO-based honeycomb reactor/heat exchanger preliminary design. In particular, cordierite monolithic structures were coated with natural CaO and in total 11 cycles were conducted. Upon operation, clear signs of heat dissipation by the imposed flow in the duration of the exothermic reaction step were identified.

  1. Graphene-based plasmonic force switch

    NASA Astrophysics Data System (ADS)

    Ghorbanzadeh, M.; Darbari, S.; Moravvej-Farshi, M. K.

    2016-03-01

    We take advantage of a Kretschmann configuration to design a plasmonic force switch. It consists of a prism/Au/SiO2 stack topped by a gated graphene sheet, as an electrically active optofluidic particle sorting system. We show that using a small gate voltage, one can switch the plasmon-wave induced force on a target particle, and hence its velocity. Simulations show that by electrical tuning of the graphene electrochemical potential in a narrow range of ˜65 meV—i.e., equivalent to an applied gate voltage of ˜4.3 V—the graphene surface plasmons can absorb the Au surface plasmons, switching off the plasmonic force exerted on the target particle with an ON/OFF ratio of more than 20. Numerical results also show that the maximum sensitivity of the particle's velocity to the graphene electrochemical potential is ˜1136 μm/eV-s. The proposed electrically active plasmonic force switch offers opportunities in developing tunable on-chip optical micromanipulations with multiple parallel functionalities and low power consumption.

  2. Force.

    ERIC Educational Resources Information Center

    Gamble, Reed

    1989-01-01

    Discusses pupil misconceptions concerning forces. Summarizes some of Assessment of Performance Unit's findings on meaning of (1) force, (2) force and motion in one dimension and two dimensions, and (3) Newton's second law. (YP)

  3. Linear thermal circulator based on Coriolis forces.

    PubMed

    Li, Huanan; Kottos, Tsampikos

    2015-02-01

    We show that the presence of a Coriolis force in a rotating linear lattice imposes a nonreciprocal propagation of the phononic heat carriers. Using this effect we propose the concept of Coriolis linear thermal circulator which can control the circulation of a heat current. A simple model of three coupled harmonic masses on a rotating platform permits us to demonstrate giant circulating rectification effects for moderate values of the angular velocities of the platform. PMID:25768443

  4. Impact of volcanism on the evolution of Lake Van (eastern Anatolia) III: Periodic (Nemrut) vs. episodic (Süphan) explosive eruptions and climate forcing reflected in a tephra gap between ca. 14 ka and ca. 30 ka

    NASA Astrophysics Data System (ADS)

    Schmincke, Hans-Ulrich; Sumita, Mari

    2014-09-01

    Fifteen Lateglacial to Holocene rhyolitic, dominantly primary tephra layers piston-cored and drilled (ICDP Paleovan drilling project) in western Lake Van (eastern Anatolia, Turkey) were precisely correlated to either of the two adjacent and active large volcanoes Nemrut and Süphan based on shard textures, mineralogy and mineral and glass compositions. The young peralkaline (comenditic to pantelleritic) primary rhyolitic Nemrut tephras are characterized by anorthoclase, hedenbergitic to augitic clinopyroxene, fayalitic olivine, minor quartz, and rare accessory chevkinite and zircon. Phenocrysts in subalkaline primary rhyolitic Süphan tephras are chiefly oligoclase-labradorite, with minor K-rich sanidine in some, biotite, amphibole, hypersthene, rare augitic clinopyroxene, relatively common allanite and rare zircon. Two contrasting explosive eruptive modes are distinguished from each other: episodic (Süphan) and periodic (Nemrut). The Lateglacial Süphan tephra swarm covers a short time interval of ca. 338 years between ca. 13,078 vy BP and 12,740 vy BP, eruptions having occurred statistically every ca. 42 years with especially short intervals between V-11 (reworked) and V-14. Causes for the strongly episodic Süphan explosive behavior might include seismic triggering of a volcano-magma system unable to erupt explosively without the benefit of external triggering, as reflected in pervasive faulting preceding the Süphan tephra swarm. Seismic triggering may have caused the rise of more mafic ("trachyandesitic") parent magma, heating near-surface pockets of highly evolved magma - that might have formed silicic domes during this stage of volcano evolution - resulting in ascent and finally explosive fragmentation of magma essentially by external factors, probably significantly enhanced by magma-water/ice interaction. Explosive eruptions of the Nemrut volcano system, interpreted to be underlain by a large fractionating magma reservoir, follow a more periodic mode of (a

  5. The effect of the phenylalkylamine D888 (devapamil) on force and Ca2+ current in isolated frog skeletal muscle fibres.

    PubMed Central

    Erdmann, R; Lüttgau, H C

    1989-01-01

    1. The effects of the (+)- and the (-)-isomer of the phenylalkylamine derivative D888 (desmethoxyverapamil or devapamil) on isometric force and slow Ca2+ inward current were investigated in short toe muscle fibres of the frog (Rana temporaria). The experiments were performed under voltage-clamp conditions with two flexible internal glass microelectrodes at 10 degrees C in a TEA sulphate solution containing approximately 4 mM-free Ca2+. 2. In the presence of 0.05-5 microM-(-)-D888 a normal phasic contracture could be induced by a depolarizing voltage step. When depolarization was maintained for some minutes the force-controlling system turned into a stabilized inactivated state (paralysis) from which it recovered upon repolarization within minutes instead of seconds. With the (+)-isomer (0.5-20 microM), a similarly retarded restoration was observed. However, it proved to be less effective than the (-)-isomer. 3. D888 caused a shift to more negative potentials of the S-shaped curve, which describes the voltage dependence of force restoration in the steady state (restoration time 15 min). The potential of half-maximum restoration in the absence of the drug (V = -35.8 mV) changed as follows. (-)-D888: -56 mV (0.05 microM), -69 mV (0.2 microM), -77.5 mV (0.5 microM), and -82 mV (5 microM); (+)-D888: -55.8 mV (0.5 microM), -76.5 mV (5 microM), and -85 mV (20 microM). 4. On the assumption that D888 binds only to the inactivated form of the voltage sensor of force control in the T-tubular membrane (modulated receptor hypothesis) the data presented in paragraph 3 allowed an estimation of the drug-receptor dissociation constants. The KD values ascertained in this way, 1.71 nM for the (-)-isomer and 12.9 nM for the (+)-isomer, are in fair agreement with those obtained from [3H]D888 binding studies by other authors. 5. A comparison between equal concentrations of the two isomers regarding their effect on the speed of restoration and the time needed to transform the sensor into

  6. Research on urban sprawl based on GIS and CA

    NASA Astrophysics Data System (ADS)

    Qin, Fen; Yan, Lijie

    2008-10-01

    The complex urban system can't be simulated directly by the traditional and static models. Cellular automata (CA) is a kind of dynamically modeling framework from bottom to top, which possesses the capability of modeling spatialtemporal evolvement process of a complicated geographical system. The peculiarities of CA are apt for simulating urban sprawl, urban expansion and land use evolution, which make the application of CA become very popular. The environment of CA simulation can be improved by using the CA model integrated with GIS to simulate the urban sprawl, and new parameters and transition rules can be found out by establishing classical urban CA. The paper summarizes the status and the application of urban CA in the world, develops a CA model named GIS-CA on the basis of the principle of CA, integrated with GIS and RS, adds urban plan as controlling factor into GIS-CA model, and uses GIS-CA model to simulate and forecast urban sprawl, and takes Luoyang City as the case study. The simulation and forecast results are acceptable for that the precision and Lee-Sallee shape index are rational.

  7. Information-based physics, influence, and forces

    SciTech Connect

    Walsh, James Lyons; Knuth, Kevin H.

    2015-01-13

    In recent works, Knuth and Bahreyni have demonstrated that the concepts of space and time are emergent in a coarse-grained model of direct particle-particle influence. In addition, Knuth demonstrated that observer-made inferences regarding the free particle, which is defined as a particle that influences others, but is not itself influenced, result in a situation identical to the Feynman checkerboard model of the Dirac equation. This suggests that the same theoretical framework that gives rise to an emergent spacetime is consistent with quantum mechanics. In this paper, we begin to explore the effect of influence on the emergent properties of a particle. This initial study suggests that when a particle is influenced, it is interpreted as accelerating in a manner consistent with special relativity implying that, at least in this situation, influence can be conceived of as a force.

  8. Acoustic radiation force-based elasticity imaging methods

    PubMed Central

    Palmeri, Mark L.; Nightingale, Kathryn R.

    2011-01-01

    Conventional diagnostic ultrasound images portray differences in the acoustic properties of soft tissues, whereas ultrasound-based elasticity images portray differences in the elastic properties of soft tissues (i.e. stiffness, viscosity). The benefit of elasticity imaging lies in the fact that many soft tissues can share similar ultrasonic echogenicities, but may have different mechanical properties that can be used to clearly visualize normal anatomy and delineate pathological lesions. Acoustic radiation force-based elasticity imaging methods use acoustic radiation force to transiently deform soft tissues, and the dynamic displacement response of those tissues is measured ultrasonically and is used to estimate the tissue's mechanical properties. Both qualitative images and quantitative elasticity metrics can be reconstructed from these measured data, providing complimentary information to both diagnose and longitudinally monitor disease progression. Recently, acoustic radiation force-based elasticity imaging techniques have moved from the laboratory to the clinical setting, where clinicians are beginning to characterize tissue stiffness as a diagnostic metric, and commercial implementations of radiation force-based ultrasonic elasticity imaging are beginning to appear on the commercial market. This article provides an overview of acoustic radiation force-based elasticity imaging, including a review of the relevant soft tissue material properties, a review of radiation force-based methods that have been proposed for elasticity imaging, and a discussion of current research and commercial realizations of radiation force based-elasticity imaging technologies. PMID:22419986

  9. An ABS control logic based on wheel force measurement

    NASA Astrophysics Data System (ADS)

    Capra, D.; Galvagno, E.; Ondrak, V.; van Leeuwen, B.; Vigliani, A.

    2012-12-01

    The paper presents an anti-lock braking system (ABS) control logic based on the measurement of the longitudinal forces at the hub bearings. The availability of force information allows to design a logic that does not rely on the estimation of the tyre-road friction coefficient, since it continuously tries to exploit the maximum longitudinal tyre force. The logic is designed by means of computer simulation and then tested on a specific hardware in the loop test bench: the experimental results confirm that measured wheel force can lead to a significant improvement of the ABS performances in terms of stopping distance also in the presence of road with variable friction coefficient.

  10. Transparent and flexible force sensor array based on optical waveguide.

    PubMed

    Kim, Youngsung; Park, Suntak; Park, Seung Koo; Yun, Sungryul; Kyung, Ki-Uk; Sun, Kyung

    2012-06-18

    This paper suggests a force sensor array measuring contact force based on intensity change of light transmitted throughout optical waveguide. For transparency and flexibility of the sensor, two soft prepolymers with different refractive index have been developed. The optical waveguide consists of two cladding layers and a core layer. The top cladding layer is designed to allow light scattering at the specific area in response to finger contact. The force sensor shows a distinct tendency that output intensity decreases with input force and measurement range is from 0 to -13.2 dB. PMID:22714510

  11. The CA Integrated Subject File II. Evaluation of Alternative Data Base Organizations

    ERIC Educational Resources Information Center

    And Others; Zipperer, William C.

    1974-01-01

    The relative retrieval performances of the CA Integrated Subject File (CAISF), CA Condensates, and a Merged File created from these two data bases were measured. Retrieval performance is reported in terms of recall, precision values, and costs. (Author/JB)

  12. A Model-Based System For Force Structure Analysis

    NASA Astrophysics Data System (ADS)

    Levitt, Tod S.; Kirby, Robert L.; Muller, Hans E.

    1985-04-01

    Given a set of image-derived vehicle detections and/or recognized military vehicles, SIGINT cues and a priori analysis of terrain, the force structure analysis (FSA) problem is to utilize knowledge of tactical doctrine and spatial deployment information to infer the existence of military forces such as batteries, companies, battalions, regiments, divisions, etc. A model-based system for FSA has been developed. It performs symbolic reasoning about force structures represented as geometric models. The FSA system is a stand-alone module which has also been developed as part of a larger system, the Advanced Digital Radar Image Exploitation System (ADRIES) for automated SAR image exploitation. The models recursively encode the component military units of a force structure, their expected spatial deployment, search priorities for model components, prior match probabilities, and type hierarchies for uncertain recognition. Partial and uncertain matching of models against data is the basic tool for building up hypotheses of the existence of force structures. Hypothesis management includes the functions of matching models against data, predicting the existence and location of unobserved force components, localization of search areas and resolution of conflicts between competing hypotheses. A subjective Bayesian inference calculus is used to accrue certainty of force structure hypotheses and resolve conflicts. Reasoning from uncertain vehicle level data, the system has successfully inferred the correct locations and components of force structures up to the battalion level. Key words: Force structure analysis, SAR, model-based reasoning, hypothesis management, search, matching, conflict resolution, Bayesian inference, uncertainty.

  13. Carboxymethyl cellulose binding to mineral substrates: characterization by atomic force microscopy-based force spectroscopy and quartz-crystal microbalance with dissipation monitoring.

    PubMed

    Pensini, Erica; Yip, Christopher M; O'Carroll, Denis; Sleep, Brent E

    2013-07-15

    The attachment of the sodium salt of carboxymethyl cellulose (CMC) onto iron oxide and various silicate substrates in aqueous solution as a function of salt concentration and pH was studied by atomic force microscopy-based force spectroscopy (AFM) and quartz-crystal microbalance with dissipation monitoring (QCM-D). Both ionic strength and cation valency were found to influence substrate binding. Notably, QCM-D experiments strongly suggested that the solubility of CMC is directly impacted by the presence of CaCl2. Such data are critical for the design of new molecules for stabilizing mineral floc dispersions and for assessing the mobility of CMC-coated particles in the subsurface. Modeling of AFM data with an extended Ohshima theory showed that van der Waals and steric forces played a major role in the interactions between CMC and mineral substrates, and that hydration forces were also important. PMID:23643251

  14. Space chimp Enos returns to Patrick Air Force Base

    NASA Technical Reports Server (NTRS)

    1961-01-01

    Enos the chimpanzee that orbited the earth twice in a Mercury spacecraft arrives back at Patrick Air Force Base. Enos landed some 220 nautical miles south of Bermuda and was picked up up by the U.S.S. Stormes.

  15. 92. FORCED DRAFT FAN & BASE OF BOILER SETTINGS SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    92. FORCED DRAFT FAN & BASE OF BOILER SETTINGS SHOWING ASH REMOVAL DOORS. NOTE STOKER LINE SHAFT DRIVE UNDER CEILING. - Lakeview Pumping Station, Clarendon & Montrose Avenues, Chicago, Cook County, IL

  16. General view. View to southwest Offutt Air Force Base, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General view. View to southwest - Offutt Air Force Base, Looking Glass Airborne Command Post, Vehicle Refueling Station, Northeast of AGE Storage Facility at far northwest end of Project Looking Glass Historic District, Bellevue, Sarpy County, NE

  17. Offutt Air Force Base, Looking Glass Airborne Command Post, Vehicle ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Offutt Air Force Base, Looking Glass Airborne Command Post, Vehicle Refueling Station, Northeast of AGE Storage Facility at far northwest end of Project Looking Glass Historic District, Bellevue, Sarpy County, NE

  18. Offutt Air Force Base, Looking Glass Airborne Command Post, Hydraulic ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Offutt Air Force Base, Looking Glass Airborne Command Post, Hydraulic Fluid Buildings, Northeast of Looking Glass Avenue at southwest side of Project Looking Glass Historic District, Bellevue, Sarpy County, NE

  19. Scanning Force Microscopy Measurements of Dissolution and Growth Processes: CaCO3 Examples

    SciTech Connect

    Baer, Donald R.; Liang, Yong; Lea, Alan S.; Amonette, James E.; Colton, Nancy G.; D.R. Baer, C.R. Clayton, G.D. Davis, et. al.

    2002-02-01

    Scanning force microscopy (SFM) provides relatively unique opportunities for the detailed study of dissolution and growth processes real time in aqueous and other solutions. By providing a detailed image of the crystallographic features as they grow or dissolve, SFM helps provide a bridge between the atomic level site-specific reactions from solution and macroscopically observable surface morphology, reaction rates and solution composition. Over the past several years we have examined the effects of solution and flow conditions on the dissolution of calcite. The anisotropic structure of steps on the calcite cleavage surface produces a delightful interplay between the movement of steps and the surface morphology. The initial work focused on the movement of steps during dissolution in''pure'' aqueous solution. This work has been followed by examination of the influence of various solution additions on the calcite dissolution and eventually the growth of a second crystal phase that appears to have an epitaxial relation to the calcite. The influence of the impurities on general calcite dissolution has been understood in terms of a''blocking'' version of the terrace ledge kink (TLK) model of surface and surface reactions.

  20. The pCa-tension and force-velocity characteristics of skinned fibres isolated from fish fast and slow muscles

    PubMed Central

    Altringham, J. D.; Johnston, I. A.

    1982-01-01

    1. Single fast fibres and small bundles of two to six slow fibres were dissected from the myotomal muscles of the cod, Gadus morhua, and the dogfish, Scyliorhinus canicula. Fibres were chemically skinned with the non-ionic detergent Brij 58. 2. The isometric tension properties were investigated. Maximal isometric tensions (mean ± S.E. of mean) were 18·65±1·18 (n = 11) and 8·34±0·98 (n = 13) N cm-2 for cod fast and slow fibres, and 18·34±0·88 (n = 28) and 8·24±0·39 (n = 12) N cm-2 for dogfish fast and slow fibres respectively. The values are comparable to those observed in mammalian and amphibian skinned fibres. The lower tensions generated by the slow fibres cannot be fully explained on the basis of their lower myofibrillar fractional volume. 3. In common with previous studies, a steep sigmoid relationship between pCa and tension was observed. The threshold for tension generation was around pCa 7·2. Half-maximal pCas were 6·08 and 6·42 for cod fast and slow muscle, and 6·41 and 6·50 for dogfish fast and slow fibres respectively. Cod fibres were maximally activated at around pCa 5·18, and dogfish fibres at pCa 5·62. 4. Contraction-induced residual tensions were observed in cod fast fibres after return to relaxing solution. This phenomenon is a feature common to many skinned fibre studies, but the mechanism behind it has yet to be resolved. 5. The force-velocity characteristics of fast and slow fibres have been investigated (at 8 °C). 6. Points below 0·6 P0 on the P-V curves could be fitted to a linear form of the Hill equation. Extrapolated Vmaxs were calculated as follows: cod fast fibre Vmax = 1·01 muscle length sec-1 (Lsec-1) (a = 0·21 P0; b = 0·21 Lsec-1). Slow fibre = 0·53 Lsec-1 (a = 0·28P0; b = 0·21 Lsec-1). Dogfish fast fibre Vmax = 2·34 Lsec-1 (a = 0·06 P0; b = 0·14 Lsec-1). Slow fibre = 0·67 Lsec-1 (a = 0·19 P0; b = 0·13 Lsec-1). 7. Contraction velocity in cod slow fibres decreased continuously to produce markedly non

  1. A piezoelectric vibration-based syringe for reducing insertion force

    NASA Astrophysics Data System (ADS)

    Huang, Y. C.; Tsai, M. C.; Lin, C. H.

    2012-12-01

    Puncturing of the human skin with a needle is perhaps the most common invasive medical procedure. Clinical studies have revealed that tissue deformation and needle deflection are the primary problem for needle misplacement in percutaneous procedures. To avoid this, various techniques for reducing insertion forces during needle insertion have been considered. This paper presents a piezoelectric vibration-based syringe to reduce insertion force. AC power was applied to the piezoelectric elements to vibrate the needle with high frequency and thereby reduce the friction and cutting forces between the needle and tissue. Vibration mode shapes of the needle were observed by finite element analysis and verified by experimental results. Effects of reducing insertion force via the vibrating needle were also confirmed by inserting the needle into the porcine tissues. The proposed syringe, which minimizes the insertion force and overcomes limitations of needle materials, can be widely utilized in robot-assisted needle insertion systems.

  2. Model-based estimation of muscle forces exerted during movements.

    PubMed

    Erdemir, Ahmet; McLean, Scott; Herzog, Walter; van den Bogert, Antonie J

    2007-02-01

    Estimation of individual muscle forces during human movement can provide insight into neural control and tissue loading and can thus contribute to improved diagnosis and management of both neurological and orthopaedic conditions. Direct measurement of muscle forces is generally not feasible in a clinical setting, and non-invasive methods based on musculoskeletal modeling should therefore be considered. The current state of the art in clinical movement analysis is that resultant joint torques can be reliably estimated from motion data and external forces (inverse dynamic analysis). Static optimization methods to transform joint torques into estimates of individual muscle forces using musculoskeletal models, have been known for several decades. To date however, none of these methods have been successfully translated into clinical practice. The main obstacles are the lack of studies reporting successful validation of muscle force estimates, and the lack of user-friendly and efficient computer software. Recent advances in forward dynamics methods have opened up new opportunities. Forward dynamic optimization can be performed such that solutions are less dependent on measured kinematics and ground reaction forces, and are consistent with additional knowledge, such as the force-length-velocity-activation relationships of the muscles, and with observed electromyography signals during movement. We conclude that clinical applications of current research should be encouraged, supported by further development of computational tools and research into new algorithms for muscle force estimation and their validation. PMID:17070969

  3. Unmanned Turning Force Control Based on the Spindle Drive Characteristics

    NASA Astrophysics Data System (ADS)

    Huh, Kunsoo; Pak, Changho

    While the rough turning process is machining a workpiece at various cutting depth, the feedrate is usually selected based on the maximum depth of cut. Even if this selection can avoid power saturation or tool breakage, it is very conservative compared to the capacity of machine tools and can reduce the productivity significantly. Many adaptive control techniques have been reported that can adjust the feedrate to maintain the constant cutting force. However, these controllers are not very widely used in manufacturing industry because of the limitations in measuring the cutting force signals and selecting the appropriate cutting force level. In this paper, an unmanned turning process control system is proposed based on the spindle drive characteristics. A synthesized cutting force monitor is introduced to estimate the cutting force as accurately as a dynamometer does. The reference cutting force level as well as the feed-rate is selected considering the spindle motor characteristics. Because the cutting process is highly nonlinear, a fuzzy logic controller is applied to maintain the desired cutting force level. The experimental results demonstrate that the proposed system can be easily realized in CNC lathe with requiring little additional hardware.

  4. Vehicle Lateral State Estimation Based on Measured Tyre Forces

    PubMed Central

    Tuononen, Ari J.

    2009-01-01

    Future active safety systems need more accurate information about the state of vehicles. This article proposes a method to evaluate the lateral state of a vehicle based on measured tyre forces. The tyre forces of two tyres are estimated from optically measured tyre carcass deflections and transmitted wirelessly to the vehicle body. The two remaining tyres are so-called virtual tyre sensors, the forces of which are calculated from the real tyre sensor estimates. The Kalman filter estimator for lateral vehicle state based on measured tyre forces is presented, together with a simple method to define adaptive measurement error covariance depending on the driving condition of the vehicle. The estimated yaw rate and lateral velocity are compared with the validation sensor measurements. PMID:22291535

  5. Toward Standardized Acoustic Radiation Force (ARF)-Based Ultrasound Elasticity Measurements With Robotic Force Control

    PubMed Central

    Kumar, Shalki; Lily, Kuo; Sen, H. Tutkun; Iordachita, Iulian; Kazanzides, Peter

    2016-01-01

    Objective Acoustic radiation force (ARF)-based approaches to measure tissue elasticity require transmission of a focused high-energy acoustic pulse from a stationary ultrasound probe and ultrasound-based tracking of the resulting tissue displacements to obtain stiffness images or shear wave speed estimates. The method has established benefits in biomedical applications such as tumor detection and tissue fibrosis staging. One limitation, however, is the dependence on applied probe pressure, which is difficult to control manually and prohibits standardization of quantitative measurements. To overcome this limitation, we built a robot prototype that controls probe contact forces for shear wave speed quantification. Methods The robot was evaluated with controlled force increments applied to a tissue-mimicking phantom and in vivo abdominal tissue from three human volunteers. Results The root-mean-square error between the desired and measured forces was 0.07 N in the phantom and higher for the fatty layer of in vivo abdominal tissue. The mean shear wave speeds increased from 3.7 to 4.5 m/s in the phantom and 1.0 to 3.0 m/s in the in vivo fat for compressive forces ranging from 2.5 to 30 N. The standard deviation of shear wave speeds obtained with the robotic approach were low in most cases (< 0.2 m/s) and comparable to that obtained with a semiquantitative landmark-based method. Conclusion Results are promising for the introduction of robotic systems to control the applied probe pressure for ARF-based measurements of tissue elasticity. Significance This approach has potential benefits in longitudinal studies of disease progression, comparative studies between patients, and large-scale multidimensional elasticity imaging. PMID:26552071

  6. Micro-Vibration-Based Slip Detection in Tactile Force Sensors

    PubMed Central

    Fernandez, Raul; Payo, Ismael; Vazquez, Andres S.; Becedas, Jonathan

    2014-01-01

    Tactile sensing provides critical information, such as force, texture, shape or temperature, in manipulation tasks. In particular, tactile sensors traditionally used in robotics are emphasized in contact force determination for grasping control and object recognition. Nevertheless, slip detection is also crucial to successfully manipulate an object. Several approaches have appeared to detect slipping, the majority being a combination of complex sensors with complex algorithms. In this paper, we deal with simplicity, analyzing how a novel, but simple, algorithm, based on micro-vibration detection, can be used in a simple, but low-cost and durable, force sensor. We also analyze the results of using the same principle to detect slipping in other force sensors based on flexible parts. In particular, we show and compare the slip detection with: (i) a flexible finger, designed by the authors, acting as a force sensor; (ii) the finger torque sensor of a commercial robotic hand; (iii) a commercial six-axis force sensor mounted on the wrist of a robot; and (iv) a fingertip piezoresistive matrix sensor. PMID:24394598

  7. AFM-based force microsensor for a microrobot

    NASA Astrophysics Data System (ADS)

    Fatikow, Sergej; Fahlbusch, Stephan

    2001-10-01

    Microrobots are the result of increasing research activities at the border between microsystem technology and robotics. Today already, robots with dimensions of a few cubic- centimeters can be developed. Like conventional robots, microrobots represent a complex system that usually contains several different types of actuators and sensors. The measurement of gripping forces is the most important sensor application in micromanipulation besides visual servoing to protect the parts from too high surface pressures and thereby damage during the assembly process. Very small forces in the range of 200 (mu) N down to 0.1 (mu) N or even less have to be sensed. Thus, the aim of our current research activities is the development of a high-resolution integrated force microsensor for measuring gripping forces in a microhandling robot. On the one hand, the sensor should be a device for teleoperated manipulation tasks in a flexible microhandling station. On the other hand, typical microhandling operations should to a large extend be automated with the aid of computer-based signal processing of sensor information. The user should be provided with an interface for teleoperated manipulation and an interface for partially automated manipulation of microobjects. In this paper, a concept for the measurement of gripping forces in microrobotics using piezoresistive AFM (atomic force microscope) cantilevers is introduced. Further on, the concept of a microrobot-based SEM station and its applications are presented.

  8. Micro-vibration-based slip detection in tactile force sensors.

    PubMed

    Fernandez, Raul; Payo, Ismael; Vazquez, Andres S; Becedas, Jonathan

    2014-01-01

    Tactile sensing provides critical information, such as force, texture, shape or temperature, in manipulation tasks. In particular, tactile sensors traditionally used in robotics are emphasized in contact force determination for grasping control and object recognition. Nevertheless, slip detection is also crucial to successfully manipulate an object. Several approaches have appeared to detect slipping, the majority being a combination of complex sensors with complex algorithms. In this paper, we deal with simplicity, analyzing how a novel, but simple, algorithm, based on micro-vibration detection, can be used in a simple, but low-cost and durable, force sensor. We also analyze the results of using the same principle to detect slipping in other force sensors based on flexible parts. In particular, we show and compare the slip detection with: (i) a flexible finger, designed by the authors, acting as a force sensor; (ii) the finger torque sensor of a commercial robotic hand; (iii) a commercial six-axis force sensor mounted on the wrist of a robot; and (iv) a fingertip piezoresistive matrix sensor. PMID:24394598

  9. GPI based velocity/force observer design for robot manipulators.

    PubMed

    Gutiérrez-Giles, Alejandro; Arteaga-Pérez, Marco A

    2014-07-01

    In many applications involving a robot in contact with a surface it is important to control the interaction between the manipulator and its environment, usually by employing force sensors. However, sometimes it is desirable to remove them due to a variety of reasons, e.g. high costs, noisy measurements and a narrow bandwidth. To overcome these drawbacks, in this work it is proposed as a velocity/force observer based on the Generalized Proportional Integral (GPI) technique. Joint velocities and contact forces are estimated with only position measurements and then used in a force/position control scheme. Ultimate boundedness of the observation errors is formally proven and an arbitrarily small ultimate bound is then achieved. Simulation results are used to validate the proposed approach. PMID:24780160

  10. Structural basis for the in situ Ca(2+) sensitization of cardiac troponin C by positive feedback from force-generating myosin cross-bridges.

    PubMed

    Rieck, Daniel C; Li, King-Lun; Ouyang, Yexin; Solaro, R John; Dong, Wen-Ji

    2013-09-15

    The in situ structural coupling between the cardiac troponin (cTn) Ca(2+)-sensitive regulatory switch (CRS) and strong myosin cross-bridges was investigated using Förster resonance energy transfer (FRET). The double cysteine mutant cTnC(T13C/N51C) was fluorescently labeled with the FRET pair 5-(iodoacetamidoethyl)aminonaphthelene-1-sulfonic acid (IAEDENS) and N-(4-dimethylamino-3,5-dinitrophenyl)maleimide (DDPM) and then incorporated into detergent skinned left ventricular papillary fiber bundles. Ca(2+) titrations of cTnC(T13C/N51C)AEDENS/DDPM-reconstituted fibers showed that the Ca(2+)-dependence of the opening of the N-domain of cTnC (N-cTnC) statistically matched the force-Ca(2+) relationship. N-cTnC opening still occurred steeply during Ca(2+) titrations in the presence of 1mM vanadate, but the maximal extent of ensemble-averaged N-cTnC opening and the Ca(2+)-sensitivity of the CRS were significantly reduced. At nanomolar, resting Ca(2+) levels, treatment with ADP·Mg in the absence of ATP caused a partial opening of N-cTnC. During subsequent Ca(2+) titrations in the presence of ADP·Mg and absence of ATP, further N-cTnC opening was stimulated as the CRS responded to Ca(2+) with increased Ca(2+)-sensitivity and reduced steepness. These findings supported our hypothesis here that strong cross-bridge interactions with the cardiac thin filament exert a Ca(2+)-sensitizing effect on the CRS by stabilizing the interaction between the exposed hydrophobic patch of N-cTnC and the switch region of cTnI. PMID:23896515

  11. Forces driving late Pleistocene (ca. 77-12 ka) landscape evolution in the Cimarron River valley, southwestern Kansas

    NASA Astrophysics Data System (ADS)

    Layzell, Anthony L.; Mandel, Rolfe D.; Ludvigson, Greg A.; Rittenour, Tammy M.; Smith, Jon J.

    2015-07-01

    This study presents stratigraphic, geomorphic, and paleoenvironmental (δ13C) data that provide insight into the late Pleistocene landscape evolution of the Cimarron River valley in the High Plains of southwestern Kansas. Two distinct valley fills (T-1 and T-2) were investigated. Three soils occur in the T-2 fill and five in the T-1 fill, all indicating periods of landscape stability or slow sedimentation. Of particular interest are two cumulic soils dating to ca. 48-28 and 13-12.5 ka. δ13C values are consistent with regional paleoenvironmental proxy data that indicate the prevalence of warm, dry conditions at these times. The Cimarron River is interpreted to have responded to these climatic changes and to local base level control. Specifically, aggradation occurred during cool, wet periods and slow sedimentation with cumulic soil formation occurred under warmer, drier climates. Significant valley incision (~ 25 m) by ca. 28 ka likely resulted from a lowering of local base level caused by deep-seated dissolution of Permian evaporite deposits.

  12. Exploring the retention properties of CaF2 nanoparticles as possible additives for dental care application with tapping-mode atomic force microscope in liquid.

    PubMed

    Wasem, Matthias; Köser, Joachim; Hess, Sylvia; Gnecco, Enrico; Meyer, Ernst

    2014-01-13

    Amplitude-modulation atomic force microscopy (AM-AFM) is used to determine the retention properties of CaF2 nanoparticles adsorbed on mica and on tooth enamel in liquid. From the phase-lag of the forced cantilever oscillation the local energy dissipation at the detachment point of the nanoparticle was determined. This enabled us to compare different as-synthesized CaF2 nanoparticles that vary in shape, size and surface structure. CaF2 nanoparticles are candidates for additives in dental care products as they could serve as fluorine-releasing containers preventing caries during a cariogenic acid attack on the teeth. We show that the adherence of the nanoparticles is increased on the enamel substrate compared to mica, independently of the substrate roughness, morphology and size of the particles. PMID:24455460

  13. Exploring the retention properties of CaF2 nanoparticles as possible additives for dental care application with tapping-mode atomic force microscope in liquid

    PubMed Central

    Köser, Joachim; Hess, Sylvia; Gnecco, Enrico; Meyer, Ernst

    2014-01-01

    Summary Amplitude-modulation atomic force microscopy (AM-AFM) is used to determine the retention properties of CaF2 nanoparticles adsorbed on mica and on tooth enamel in liquid. From the phase-lag of the forced cantilever oscillation the local energy dissipation at the detachment point of the nanoparticle was determined. This enabled us to compare different as-synthesized CaF2 nanoparticles that vary in shape, size and surface structure. CaF2 nanoparticles are candidates for additives in dental care products as they could serve as fluorine-releasing containers preventing caries during a cariogenic acid attack on the teeth. We show that the adherence of the nanoparticles is increased on the enamel substrate compared to mica, independently of the substrate roughness, morphology and size of the particles. PMID:24455460

  14. Kinetics of Isothermal Melt Crystallization in CaO-SiO2-CaF2-Based Mold Fluxes

    NASA Astrophysics Data System (ADS)

    Seo, Myung-Duk; Shi, Cheng-Bin; Baek, Ji-Yeon; Cho, Jung-Wook; Kim, Seon-Hyo

    2015-10-01

    A kinetic study for isothermal melt crystallization of CaO-SiO2-CaF2-based mold fluxes with different basicity of 0.94 and 1.34 has been carried out systematically by DSC measurements. The kinetic parameters were determined by Johnson-Mehl-Avrami equation. The average Avrami exponent of cuspidine (3CaO·2SiO2·CaF2) crystallization for mold flux of lower basicity (0.94) is calculated to be 3.1, implying that the crystallization mode is instantaneous nucleation followed by 3-dimensional growth. For the mold flux of higher basicity (1.34), the average Avrami exponent of cuspidine equals to 3.4, strongly suggesting that the growth is still 3 dimensional but the nucleation should be continuous. It was found that the effective crystallization rate constant for both mold fluxes increases as the crystallization temperature decreases, showing that the crystallization rate could be governed by nucleation rate. The negative effective activation energy indicates an anti-Arrhenius behavior for crystallization of the mold fluxes studied. Therefore, it is concluded that the melt crystallization for the commercial mold fluxes will be determined by thermodynamics of nucleation which is relevant to degree of undercooling. The morphology of cuspidine crystals observed by SEM agreeds well with the isothermal crystallization kinetics results.

  15. CHARGE-BASED FORCES AT THE NAFION-WATER INTERFACE

    PubMed Central

    Das, Ronnie; Pollack, Gerald H.

    2013-01-01

    Interfacial water lying next to hydrophilic surfaces has been shown to be spectroscopically, mechanically, and electrically distinct from bulk water. Interfacial water has also been shown to exclude negatively- and positively-charged microspheres, and has thus become known as the “exclusion zone.” Measurements have demonstrated that exclusion zones exhibit a negative electrical potential on the order of −100 mV relative to bulk water, with a corresponding distribution of positive protons in the bulk water region beyond the exclusion zone. This separation of charge is hypothesized to create an electrostatic force between the exclusion zone and the proton-enriched zone beyond. To test this hypothesis, a hydrophilic Nafion ring was attached to the tip of a deflectable ribbon-like force sensor. The sensor was designed to obstruct the flow of protons from one side of the lever to the other, so that any proton-based force would remain unilateral. pH-sensitive dye measurements confirmed that the protons were largely confined to one side. When the lever assembly was exposed to water, the sensor deflected toward the protons. Over a period of 20 min, deflection amounted to approximately 20 μm, corresponding to a force of approximately 22 μN. Hence, electrostatic forces are confirmed. If exclusion zones exist ubiquitously at hydrophilic surfaces, including biological surfaces, then the resulting electrostatic forces may play significant roles in many biological phenomena including adhesion and protein folding. PMID:23311934

  16. Charge-based forces at the Nafion-water interface.

    PubMed

    Das, Ronnie; Pollack, Gerald H

    2013-02-26

    Interfacial water lying next to hydrophilic surfaces has been shown to be spectroscopically, mechanically, and electrically distinct from bulk water. Interfacial water has also been shown to exclude negatively and positively charged microspheres and has thus become known as the "exclusion zone". Measurements have demonstrated that exclusion zones exhibit a negative electrical potential on the order of -100 mV relative to bulk water, with a corresponding distribution of positive protons in the bulk water region beyond the exclusion zone. This separation of charge is hypothesized to create an electrostatic force between the exclusion zone and the proton-enriched zone beyond. To test this hypothesis, a hydrophilic Nafion ring was attached to the tip of a deflectable ribbonlike force sensor. The sensor was designed to obstruct the flow of protons from one side of the lever to the other, so that any proton-based force would remain unilateral. pH-sensitive dye measurements confirmed that the protons were largely confined to one side. When the lever assembly was exposed to water, the sensor deflected toward the protons. Over a period of 20 min, deflection amounted to approximately 20 μm, corresponding to a force of approximately 22 μN. Hence, electrostatic forces are confirmed. If exclusion zones exist ubiquitously at hydrophilic surfaces, including biological surfaces, then the resulting electrostatic forces may play significant roles in many biological phenomena including adhesion and protein folding. PMID:23311934

  17. Effect of Microstructure on Reliability of Ca(TiZr)O3-Based Multilayer Ceramic Capacitors

    NASA Astrophysics Data System (ADS)

    Motoki, Tomoo; Naito, Masahiro; Sano, Harunobu; Konoike, Takehiro; Tomono, Kunisaburo

    2000-09-01

    We examined the reliability of Ca(TiZr)O3 (CTZ)-based Ni-electrode multilayer ceramic capacitors (MLCs) prepared by two different processes with particular interest in the microstructure. One process was to calcine the mixture of CaCO3 and TiO2 to prepare CaTiO3 (CT) powder and the mixture of CaCO3 and ZrO2 to prepare CaZrO3 (CZ) powder, and then mix these calcined powders and sinter them to synthesize the CTZ-based ceramics. The other was to calcine the mixture of CaCO3, TiO2 and ZrO2 powders together to prepare CTZ powder and then sinter them. These two processes of CTZ ceramic preparation resulted in a different crystallinity and distribution of the elements. We found that these factors influenced the reliability of CTZ-based MLCs.

  18. STRUCTURAL TRANSFORMATIONS IN CA-BASED SORBENTS USED FOR SO2 EMISSION CONTROL

    EPA Science Inventory

    The paper discusses structural transformations in Ca-based sorbents used for SO2 emission control. conomizer temperature injection of Ca-based sorbents is an option for dry control of SO2 emissions from coal-fired boilers. heir reactivity with SO2 was found to be a function of th...

  19. 33 CFR 165.1120 - Security Zone; Naval Amphibious Base, San Diego, CA.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Security Zone; Naval Amphibious Base, San Diego, CA. 165.1120 Section 165.1120 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 165.1120 Security Zone; Naval Amphibious Base, San Diego, CA. (a) Location. The following area is...

  20. The Campus-Based Formula. NASFAA Task Force Report

    ERIC Educational Resources Information Center

    National Association of Student Financial Aid Administrators, 2014

    2014-01-01

    The primary purpose of the National Association of Student Financial Aid Administrators (NASFAA) Campus-Based Aid Allocation Task Force was to examine the formula by which congressional appropriations for the Federal Supplemental Educational Opportunity Grant (FSEOG), Federal Work-Study (FWS), and Perkins Loan programs are distributed to schools,…

  1. STS-67 landing at Edwards Air Force Base

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The drag chute is fully deployed in this view of the Space Shuttle Endeavour as it completes a mission of almost 17 days duration in space on runway 22 at Edwards Air Force Base in southern California. Landing occurred at 1:46 p.m. (EST), March 18, 1995.

  2. STS-67 landing at Edwards Air Force Base

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Space Shuttle Endeavour, after completing a mission of almost 17 days duration in space, touches down on runway 22 at Edwards Air Force Base in southern California. Landing occurred at 1:46 p.m. (EST), March 18, 1995. In this photo the nose gear is still in the air as the orbiter touches down.

  3. STS-66 landing at Edwards Air Force Base

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The main landing gear is on the ground and the nose gear is about to touch down as the Space Shuttle Atlantis heads toward a stop at Edwards Air Force Base in southern California, ending a successful 10 day, 22 hour and 34 minute space mission. Landing occured at 7:34 a.m. (PST), November 14, 1994.

  4. STS-66 landing at Edwards Air Force Base

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The drag chute is fully deployed as the Space Shuttle Atlantis heads toward a stop at Edwards Air Force Base in southern California, ending a successful 10 day, 22 hour and 34 minute space mission. Landing occured at 7:34 a.m. (PST), November 14, 1994.

  5. REACTION KINETICS OF CA-BASED SORBENTS WITH HC1

    EPA Science Inventory

    The paper gives results of an investigation of the kinetics of the reaction between CaO and HC1 under conditions that minimize bulk mass transfer and pore diffusion limitations. eactivity data from 0.2 to 1 s exposure to 5000 ppm HC1 in a fixed-bed reactor were analyzed by a shri...

  6. REACTION KINETICS OF CA-BASED SORBENTS WITH HC1

    EPA Science Inventory

    The kinetics of the reaction between CaO and HCl were investigated under conditions that minimize bulk mass transfer and pore diffusion limitations. Reactivity data from 0.2- to 1-s exposure to 5000 ppm HCl in a fixed bed reactor were analyzed by a shrinking core model of diffusi...

  7. Geothermal-resource verification for Air Force bases

    SciTech Connect

    Grant, P.R. Jr.

    1981-06-01

    This report summarizes the various types of geothermal energy reviews some legal uncertainties of the resource and then describes a methodology to evaluate geothermal resources for applications to US Air Force bases. Estimates suggest that exploration costs will be $50,000 to $300,000, which, if favorable, would lead to drilling a $500,000 exploration well. Successful identification and development of a geothermal resource could provide all base, fixed system needs with an inexpensive, renewable energy source.

  8. Model based control of dynamic atomic force microscope

    SciTech Connect

    Lee, Chibum; Salapaka, Srinivasa M.

    2015-04-15

    A model-based robust control approach is proposed that significantly improves imaging bandwidth for the dynamic mode atomic force microscopy. A model for cantilever oscillation amplitude and phase dynamics is derived and used for the control design. In particular, the control design is based on a linearized model and robust H{sub ∞} control theory. This design yields a significant improvement when compared to the conventional proportional-integral designs and verified by experiments.

  9. Model based control of dynamic atomic force microscope.

    PubMed

    Lee, Chibum; Salapaka, Srinivasa M

    2015-04-01

    A model-based robust control approach is proposed that significantly improves imaging bandwidth for the dynamic mode atomic force microscopy. A model for cantilever oscillation amplitude and phase dynamics is derived and used for the control design. In particular, the control design is based on a linearized model and robust H(∞) control theory. This design yields a significant improvement when compared to the conventional proportional-integral designs and verified by experiments. PMID:25933864

  10. A flexible piezoelectric force sensor based on PVDF fabrics

    NASA Astrophysics Data System (ADS)

    Wang, Y. R.; Zheng, J. M.; Ren, G. Y.; Zhang, P. H.; Xu, C.

    2011-04-01

    Polyvinylidene fluoride (PVDF) film has been widely investigated as a sensor and transducer material due to its high piezo-, pyro- and ferroelectric properties. To activate these properties, PVDF films require a mechanical treatment, stretching or poling. In this paper, we report on a force sensor based on PVDF fabrics with excellent flexibility and breathability, to be used as a specific human-related sensor. PVDF nanofibrous fabrics were prepared by using an electrospinning unit and characterized by means of scanning electron microscopy (SEM), FTIR spectroscopy and x-ray diffraction. Preliminary force sensors have been fabricated and demonstrated excellent sensitivity and response to external mechanical forces. This implies that promising applications can be made for sensing garment pressure, blood pressure, heartbeat rate, respiration rate and accidental impact on the human body.

  11. Exploring Mg-Zn-Ca-Based Bulk Metallic Glasses for Biomedical Applications Based on Thermodynamic Approach

    NASA Astrophysics Data System (ADS)

    Ramya, M.; Sarwat, Syed Ghazi; Udhayabanu, V.; Raj, Baldev; Ravi, K. R.

    2015-12-01

    Magnesium (Mg)-based metallic glasses are considered as possible candidates in orthopedic implant applications. This paper aims to theoretically predict the glass-forming ability (GFA) in Mg-Zn-Ca alloy using a newly proposed thermodynamic model ( P HHS), and the consistency of this model is verified through experimental analysis. P HHS is based on thermodynamic parameters such as enthalpy of chemical mixing, elastic enthalpy, and configurational entropy, thus incorporating the pivotal effects, i.e., electron transfer effects, effect of atomic size mismatch, and effect of randomness, which aid to high GFA. In essence, P HHS can be visualized as the energy barrier that exists between the transformations of random atomic structure of glass to ordered crystalline structure. When the P HHS value is more negative, the energy barrier will be high, supporting easy glass formation. Various Mg-Zn-Ca metallic glass compositions displayed almost an expected and supporting trend, where the critical diameter of the metallic glass rod increased with a more negative P HHS value. Among the predicted Mg-Zn-Ca systems, the Mg60Zn35Ca5 composition shows deviation from the expected trend. This discrepancy has been clearly elucidated using a eutectic phase diagram. In addition to the consistency of the P HHS parameter to verifying the GFA of various compositions, the unique ability of this model is to predict unexplored Mg-Zn-Ca glass-forming compositions using contour development. Thus, proving P HHS parameter to be used as an efficient tool in predicting new glass-forming compositions.

  12. Eielson Air Force Base Operable Unit 2 baseline risk assessment

    SciTech Connect

    Lewis, R.E.; Jarvis, T.T.; Jarvis, M.R.; Whelan, G.

    1994-10-01

    Operable Unit 2 at Eielson Air Force Base (AFB) near Fairbanks, is one of several operable units characterized by petroleum, oil, and lubricant contamination, and by the presence of organic products floating at the water table, as a result of Air Force operations since the 1940s. The base is approximately 19,270 acres in size, and comprises the areas for military operations and a residential neighborhood for military dependents. Within Operable Unit 2, there are seven source areas. These source areas were grouped together primarily because of the contaminants released and hence are not necessarily in geographical proximity. Source area ST10 includes a surface water body (Hardfill Lake) next to a fuel spill area. The primary constituents of concern for human health include benzene, toluene, ethylbenzene, and xylenes (BTEX). Monitored data showed these volatile constituents to be present in groundwater wells. The data also showed an elevated level of trace metals in groundwater.

  13. Long-Term Changes in Calcium (Ca) Sources in Base-Poor Forest Ecosystem: Insight from Stable Ca-Isotopes in Tree Rings

    NASA Astrophysics Data System (ADS)

    Farkas, J.; Dejeant, A.; Orwig, D.; Jacobsen, S. B.

    2009-12-01

    Calcium (Ca) is an essential nutrient in higher plants and also a major base-cation predicted to be most affected by environmental perturbations such as acid rain deposition and/or excessive biomass harvesting. Therefore, a better understanding of the Ca cycling in terrestrial environment is of primary interest and critical for the sustainable forest management. The aim of this project was to investigate the use of Ca isotopes as a tracer of the forest Ca cycle and its evolution through time. Here we present stable Ca isotope composition (δ44/40Ca and δ44/42Ca) and elemental concentrations of a 260-year record of tree-rings from Red Oak (Quercus rubra). The core sample was collected at an undisturbed old-growth forest site in southern New England (Wachusett Mountain, MA, USA) developed on granitic bedrock. The associated soils (sandy loams) are thus naturally base-poor and sensitive to the loss of Ca due to increased acid rain deposition and/or excessive biological uptake. The δ44/40Ca (NIST) record of decadal tree-ring increments shows a general declining trend from -0.35 to -0.80 ±0.1 per mil (from year 1750 to 2000). Superimposed on this long-term δ44/40Ca trend is a systematic negative excursion with a minimum of -0.95 ±0.1 per mil dated between 1870 and 1950. Overall, the long-term δ44/40Ca record shows statistically significant correlation with Ca/Sr ratios (R2 = 0.87, p < .01) as well as Na/Ca data (R2 = 0.69, p < .01). The fact that δ44/40Ca correlates also with Na/Ca suggest that the observed Ca isotope variations are likely related to changes in soil-Ca sources rather than being a consequence of biological processes within the tree. This is because the sodium budget of trees and forests is primarily controlled by silicate weathering rates derived from the dissolution of Na-rich minerals such as plagioclase and/or K-feldspar. Nevertheless, the role of biological processes on tree-ring δ44/40Ca record will be tested independently via measurements

  14. F-1 Engine Test Firing at Edwards Air Force Base

    NASA Technical Reports Server (NTRS)

    1962-01-01

    This photograph depicts the Rocketdyne static firing of the F-1 engine at the towering 76-meter Test Stand 1-C in Area 1-125 of the Edwards Air Force Base in California. The Saturn V S-IC (first) stage utilized five F-1 engines for its thrust. Each engine provided 1,500,000 pounds, for a combined thrust of 7,500,000 pounds with liquid oxygen and kerosene as its propellants.

  15. Jamming transitions in force-based models for pedestrian dynamics.

    PubMed

    Chraibi, Mohcine; Ezaki, Takahiro; Tordeux, Antoine; Nishinari, Katsuhiro; Schadschneider, Andreas; Seyfried, Armin

    2015-10-01

    Force-based models describe pedestrian dynamics in analogy to classical mechanics by a system of second order ordinary differential equations. By investigating the linear stability of two main classes of forces, parameter regions with unstable homogeneous states are identified. In this unstable regime it is then checked whether phase transitions or stop-and-go waves occur. Results based on numerical simulations show, however, that the investigated models lead to unrealistic behavior in the form of backwards moving pedestrians and overlapping. This is one reason why stop-and-go waves have not been observed in these models. The unrealistic behavior is not related to the numerical treatment of the dynamic equations but rather indicates an intrinsic problem of this model class. Identifying the underlying generic problems gives indications how to define models that do not show such unrealistic behavior. As an example we introduce a force-based model which produces realistic jam dynamics without the appearance of unrealistic negative speeds for empirical desired walking speeds. PMID:26565291

  16. Jamming transitions in force-based models for pedestrian dynamics

    NASA Astrophysics Data System (ADS)

    Chraibi, Mohcine; Ezaki, Takahiro; Tordeux, Antoine; Nishinari, Katsuhiro; Schadschneider, Andreas; Seyfried, Armin

    2015-10-01

    Force-based models describe pedestrian dynamics in analogy to classical mechanics by a system of second order ordinary differential equations. By investigating the linear stability of two main classes of forces, parameter regions with unstable homogeneous states are identified. In this unstable regime it is then checked whether phase transitions or stop-and-go waves occur. Results based on numerical simulations show, however, that the investigated models lead to unrealistic behavior in the form of backwards moving pedestrians and overlapping. This is one reason why stop-and-go waves have not been observed in these models. The unrealistic behavior is not related to the numerical treatment of the dynamic equations but rather indicates an intrinsic problem of this model class. Identifying the underlying generic problems gives indications how to define models that do not show such unrealistic behavior. As an example we introduce a force-based model which produces realistic jam dynamics without the appearance of unrealistic negative speeds for empirical desired walking speeds.

  17. Capillary and van der Waals interactions on CaF2 crystals from amplitude modulation AFM force reconstruction profiles under ambient conditions

    PubMed Central

    Calò, Annalisa; Robles, Oriol Vidal; Santos, Sergio

    2015-01-01

    Summary There has been much interest in the past two decades to produce experimental force profiles characteristic of the interaction between nanoscale objects or a nanoscale object and a plane. Arguably, the advent of the atomic force microscope AFM was instrumental in driving such efforts because, in principle, force profiles could be recovered directly. Nevertheless, it has taken years before techniques have developed enough as to recover the attractive part of the force with relatively low noise and without missing information on critical ranges, particularly under ambient conditions where capillary interactions are believed to dominate. Thus a systematic study of the different profiles that may arise in such situations is still lacking. Here we employ the surfaces of CaF2, on which nanoscale water films form, to report on the range and force profiles that might originate by dynamic capillary interactions occurring between an AFM tip and nanoscale water patches. Three types of force profiles were observed under ambient conditions. One in which the force decay resembles the well-known inverse-square law typical of van der Waals interactions during the first 0.5–1 nm of decay, a second one in which the force decays almost linearly, in relatively good agreement with capillary force predicted by the constant chemical potential approximation, and a third one in which the attractive force is almost constant, i.e., forms a plateau, up to 3–4 nm above the surface when the formation of a capillary neck dominates the tip–sample interaction. PMID:25977852

  18. Utilization of geothermal resources at United States Air Force bases

    SciTech Connect

    Grogger, P.K.

    1980-09-01

    The Air Force installations on the continental United States as well as Alaska and Hawaii, were evaluated as to the possibility of utilizing geothermal energy to develop electricity, produce process steam, or heat and/or cool buildings. Twenty-five bases have suspected geothermal resources available. Because of either need or available technology seven installations were rated priority I, six were rated priority II and priority III and IV totaled ten. Geological and geophysical data indicated further investigation of the priority I installations, Saylor Creek Range, Idaho, Ellsworth AFB, South Dakota, Charleston AFB, South Carolina, Kirkland AFB, New Mexico, Vandenberg AFB, California, Luke AFB, Arizona, and Williams AFB, Arizona, should be accomplished as soon as possible. The use of geothermal energy will decrease the need for fossil fuels by the USAF and during times of short supply allow such fuels to be used for the Air Force's primary mission, military defense.

  19. Extracellular Ca2+-induced force restoration in K+-depressed skeletal muscle of the mouse involves an elevation of [K+]i: implications for fatigue

    PubMed Central

    Leader, John P.; Loiselle, Denis S.; Higgins, Amanda; Lin, Wei; Renaud, Jean-Marc

    2015-01-01

    We examined whether a Ca2+-K+ interaction was a potential mechanism operating during fatigue with repeated tetani in isolated mouse muscles. Raising the extracellular Ca2+ concentration ([Ca2+]o) from 1.3 to 10 mM in K+-depressed slow-twitch soleus and/or fast-twitch extensor digitorum longus muscles caused the following: 1) increase of intracellular K+ activity by 20–60 mM (raised intracellular K+ content, unchanged intracellular fluid volume), so that the K+-equilibrium potential increased by ∼10 mV and resting membrane potential repolarized by 5–10 mV; 2) large restoration of action potential amplitude (16–54 mV); 3) considerable recovery of excitable fibers (∼50% total); and 4) restoration of peak force with the peak tetanic force-extracellular K+ concentration ([K+]o) relationship shifting rightward toward higher [K+]o. Double-sigmoid curve-fitting to fatigue profiles (125 Hz for 500 ms, every second for 100 s) showed that prior exposure to raised [K+]o (7 mM) increased, whereas lowered [K+]o (2 mM) decreased, the rate and extent of force loss during the late phase of fatigue (second sigmoid) in soleus, hence implying a K+ dependence for late fatigue. Prior exposure to 10 mM [Ca2+]o slowed late fatigue in both muscle types, but was without effect on the extent of fatigue. These combined findings support our notion that a Ca2+-K+ interaction is plausible during severe fatigue in both muscle types. We speculate that a diminished transsarcolemmal K+ gradient and lowered [Ca2+]o contribute to late fatigue through reduced action potential amplitude and excitability. The raised [Ca2+]o-induced slowing of fatigue is likely to be mediated by a higher intracellular K+ activity, which prolongs the time before stimulation-induced K+ efflux depolarizes the sarcolemma sufficiently to interfere with action potentials. PMID:25571990

  20. Inhibition of Rho-associated kinase blocks agonist-induced Ca2+ sensitization of myosin phosphorylation and force in guinea-pig ileum

    PubMed Central

    Swärd, Karl; Dreja, Karl; Susnjar, Marija; Hellstrand, Per; Hartshorne, David J; Walsh, Michael P

    2000-01-01

    Ca2+ sensitization of smooth muscle contraction involves the small GTPase RhoA, inhibition of myosin light chain phosphatase (MLCP) and enhanced myosin regulatory light chain (LC20) phosphorylation. A potential effector of RhoA is Rho-associated kinase (ROK).The role of ROK in Ca2+ sensitization was investigated in guinea-pig ileum.Contraction of permeabilized muscle strips induced by GTPγS at pCa 6.5 was inhibited by the kinase inhibitors Y-27632, HA1077 and H-7 with IC50 values that correlated with the known Ki values for inhibition of ROK. GTPγS also increased LC20 phosphorylation and this was prevented by HA1077. Contraction and LC20 phosphorylation elicited at pCa 5.75 were, however, unaffected by HA1077.Pre-treatment of intact tissue strips with HA1077 abolished the tonic component of carbachol-induced contraction and the sustained elevation of LC20 phosphorylation, but had no effect on the transient or sustained increase in [Ca2+]i induced by carbachol.LC20 phosphorylation and contraction dynamics suggest that the ROK-mediated increase in LC20 phosphorylation is due to MLCP inhibition, not myosin light chain kinase activation.In the absence of Ca2+, GTPγS stimulated 35S incorporation from [35S]ATPγS into the myosin targeting subunit of MLCP (MYPT). The enhanced thiophosphorylation was inhibited by HA1077. No thiophosphorylation of LC20 was detected.These results indicate that ROK mediates agonist-induced increases in myosin phosphorylation and force by inhibiting MLCP activity through phosphorylation of MYPT. Under Ca2+-free conditions, ROK does not appear to phosphorylate LC20in situ, in contrast to its ability to phosphorylate myosin in vitro. In particular, ROK activation is essential for the tonic phase of agonist-induced contraction. PMID:10618150

  1. Energy storage for a lunar base by the reversible chemical reaction: CaO+H2O reversible reaction Ca(OH)2

    NASA Technical Reports Server (NTRS)

    Perez-Davis, Marla E.; Difilipo, Frank

    1990-01-01

    A thermochemical solar energy storage concept involving the reversible reaction CaO + H2O yields Ca(OH)2 is proposed as a power system element for a lunar base. The operation and components of such a system are described. The CaO/H2O system is capable of generating electric power during both the day and night. The specific energy (energy to mass ratio) of the system was estimated to be 155 W-hr/kg. Mass of the required amount of CaO is neglected since it is obtained from lunar soil. Potential technical problems, such as reactor design and lunar soil processing, are reviewed.

  2. Atomic force microscopy-based shape analysis of heart mitochondria.

    PubMed

    Lee, Gi-Ja; Park, Hun-Kuk

    2015-01-01

    Atomic force microscopy (AFM) has become an important medical and biological tool for the noninvasive imaging of cells and biomaterials in medical, biological, and biophysical research. The major advantages of AFM over conventional optical and electron microscopes for bio-imaging include the facts that no special coating is required and that imaging can be done in all environments-air, vacuum, or aqueous conditions. In addition, it can also precisely determine pico-nano Newton force interactions between the probe tip and the sample surface from force-distance curve measurements.It is widely known that mitochondrial swelling is one of the most important indicators of the opening of the mitochondrial permeability transition (MPT) pore. As mitochondrial swelling is an ultrastructural change, quantitative analysis of this change requires high-resolution microscopic methods such as AFM. Here, we describe the use of AFM-based shape analysis for the characterization of nanostructural changes in heart mitochondria resulting from myocardial ischemia-reperfusion injury. PMID:25634291

  3. Waste management issues at US Air Force bases

    SciTech Connect

    Doesburg, J.M.

    1992-05-01

    Air Force installations are industrial bases for projecting men and machinery around the globe. Supporting this mission typically requires large quantities of stockpiled potentially hazardous materials. Over the past several decades, spills, poor accounting, mis-handling, and lack of understanding have led to discharges of hazardous substances into the environment. The Installation Restoration Program (IRP) is a Department of Defense directed program aimed at remediating discharges of hazardous substances, POL (petroleum, oil, and lubricants), and solid waste disposal at defense installations. The IRP is broader in scope than even the US EPA Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), and requires the Air Force managers to integrate their programs with a broad range of regulations (See Table 1 below). Managing the wastes generated by the remediation program is one of the unexpected problems the Air Force has faced in their remediation efforts. The traditional approach to remediating sites in the US has been to remove the material and place it in a secure landfill, or in the case of groundwater, to pump and treat the effluent. These technologies have proven to be very expensive and don`t really fix the problem. The waste is just moved from one place to another. Moreover, these policies ignore a fundamental technology available to today`s environmental managers: waste minimization.

  4. Waste management issues at US Air Force bases

    SciTech Connect

    Doesburg, J.M.

    1992-05-01

    Air Force installations are industrial bases for projecting men and machinery around the globe. Supporting this mission typically requires large quantities of stockpiled potentially hazardous materials. Over the past several decades, spills, poor accounting, mis-handling, and lack of understanding have led to discharges of hazardous substances into the environment. The Installation Restoration Program (IRP) is a Department of Defense directed program aimed at remediating discharges of hazardous substances, POL (petroleum, oil, and lubricants), and solid waste disposal at defense installations. The IRP is broader in scope than even the US EPA Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), and requires the Air Force managers to integrate their programs with a broad range of regulations (See Table 1 below). Managing the wastes generated by the remediation program is one of the unexpected problems the Air Force has faced in their remediation efforts. The traditional approach to remediating sites in the US has been to remove the material and place it in a secure landfill, or in the case of groundwater, to pump and treat the effluent. These technologies have proven to be very expensive and don't really fix the problem. The waste is just moved from one place to another. Moreover, these policies ignore a fundamental technology available to today's environmental managers: waste minimization.

  5. Terbium induced glassy magnetism in La,Ca-based cobaltites

    SciTech Connect

    Maryško, M. Hejtmánek, J.; Jirák, Z.; Kaman, O.; Knížek, K.

    2014-05-07

    The La{sub 0.8–x}Tb{sub x}Ca{sub 0.2}CoO{sub 3} cobaltites of orthoperovskite Pbnm structure were investigated by the X-ray and neutron diffraction, specific heat, and magnetization measurements. The terbium doping has two important effects, it increases the size disorder on perovskite A-sites and influences the magnetic properties due to large Ising-type moments (∼8.9 Bohr magnetons per Tb). The compounds show a bulk magnetic moment below T{sub C} = 82 K, 53 K, and 30 K for x = 0.1, 0.2, and 0.3, respectively. The neutron diffraction evidences a long-range ferromagnetic arrangement of cobalt moments, combined below ∼20 K with ordering of terbium moments in a canted arrangement. A homogeneous magnetic phase is proved for the x = 0.1 sample, while x = 0.2 and 0.3 are in an intrinsically non-homogeneous magnetic state with long-range ordering only comprising 55% and 30% of the sample volumes. The ac susceptibility experiments prove a glassy character of the terbium doped samples and provide arguments for the short-range ordering above T{sub C} and wide distribution of relaxation times.

  6. Smartphone-based portable intensity modulated force sensor

    NASA Astrophysics Data System (ADS)

    Negri, Lucas H.; Schiefer, Elberth M.; Paterno, Aleksander S.; Muller, Marcia; Fabris, José L.

    2015-09-01

    This work proposes a low-cost force sensor, based on intensity modulation in an optical fibre. The transducer element is composed of a knot in a single mode fibre embedded to a silicone adhesive cuboid, and can be easily fabricated. A simple sensing scheme is devised by using a visible light source and a CCD camera of a smartphone, allowing implementation costs to be reduced. Experimental results have shown that the sensor presents a linear response and a standard uncertainty of 1:07N within the dynamical range from 0 to 30 N.

  7. Vandenberg Air Force Base Pressure Gradient Wind Study

    NASA Technical Reports Server (NTRS)

    Shafer, Jaclyn A.

    2013-01-01

    Warning category winds can adversely impact day-to-day space lift operations at Vandenberg Air Force Base (VAFB) in California. NASA's Launch Services Program and other programs at VAFB use wind forecasts issued by the 30 Operational Support Squadron Weather Flight (30 OSSWF) to determine if they need to limit activities or protect property such as a launch vehicle. The 30 OSSWF tasked the AMU to develop an automated Excel graphical user interface that includes pressure gradient thresholds between specific observing stations under different synoptic regimes to aid forecasters when issuing wind warnings. This required the AMU to determine if relationships between the variables existed.

  8. Determination of Base Binding Strength and Base Stacking Interaction of DNA Duplex Using Atomic Force Microscope

    PubMed Central

    Zhang, Tian-biao; Zhang, Chang-lin; Dong, Zai-li; Guan, Yi-fu

    2015-01-01

    As one of the most crucial properties of DNA, the structural stability and the mechanical strength are attracting a great attention. Here, we take advantage of high force resolution and high special resolution of Atom Force Microscope and investigate the mechanical force of DNA duplexes. To evaluate the base pair hydrogen bond strength and base stacking force in DNA strands, we designed two modes (unzipping and stretching) for the measurement rupture forces. Employing k-means clustering algorithm, the ruptured force are clustered and the mean values are estimated. We assessed the influence of experimental parameters and performed the force evaluation for DNA duplexes of pure dG/dC and dA/dT base pairs. The base binding strength of single dG/dC and single dA/dT were estimated to be 20.0 ± 0.2 pN and 14.0 ± 0.3 pN, respectively, and the base stacking interaction was estimated to be 2.0 ± 0.1 pN. Our results provide valuable information about the quantitative evaluation of the mechanical properties of the DNA duplexes. PMID:25772017

  9. Eielson Air Force Base OU-1 baseline risk assessment

    SciTech Connect

    Jarvis, M.T.; Jarvis, T.T.; Van Houten, N.C.; Lewis, R.E.

    1993-09-01

    This Baseline Risk Assessment report is the second volume in a set of three volumes for operable Unit 1 (OU-1). The companion documents contain the Remedial Investigation and the Feasibility Study. Operable Unit 1 (OU-1) is one of several groups of hazardous waste sites located at Eielson Air Force Base (AFB) near Fairbanks, Alaska. The operable units at Eielson are typically characterized by petroleum, oil, lubricant/solvent contamination, and by the presence of organics floating at the water table. In 1989 and 1990, firms under contract to the Air Force conducted field studies to gather information about the extent of chemical contamination in soil, groundwater, and soil air pore space (soil gas) at the site. This report documents the results of a baseline risk assessment, which uses the 1989 and 1991 site characterization database to quantify the potential human health risk associated with past Base industrial activities in the vicinity of OU-1. Background data collected in 1992 were also used in the preparation of this report.

  10. Robins Air Force Base solar cogeneration facility, volume 1

    NASA Astrophysics Data System (ADS)

    1981-08-01

    A conceptual design and cost estimate for a demonstration solar facility to generate electricity and deliver process steam to the existing base distribution systems is considered. The solar energy system is a central receiver arrangement. The technical approach to the project and the rationale for selecting the site at Robins Air Force Base are discussed. The evaluation of alternative configurations considered to have potential for improving the facility value is summarized. The solar facility is described, including system level functional requirements, design, operation, performance, cost, safety, environmental, institutional, and regulatory considerations. The design, functional requirements and operating characteristics which influence cost or performance for each subsystem are described. The subsystems are the collector, receiver/tower, master control, electric power generation, and facility steam and feedwater subsystems.

  11. Capaciflector-based virtual force control and centering

    NASA Technical Reports Server (NTRS)

    Nguyen, Charles C.

    1993-01-01

    This report presents a novel concept of force control, called virtual force control. The virtual force concept avoids sudden step transition of position control to contact force control resulting in contact force disturbance when a robot end-effector makes contact with the environment. A virtual force/position control scheme consists of two loops: the force control loop and the position control loop. While the position control loop regulates the free motion, the force control loop regulates the contact force after making contact with the environment and the virtual force measured by a range sensor called capaciflector in the virtual environment. After presenting the concept of virtual force control, the report introduces a centering scheme in which the virtual force controller is employed to measure three points on a cone so that its center can be located. Experimental results of a one-degree-of-freedom virtual force control scheme applied in berthing an orbital replaceable unit are reported and compared with those of conventional pure contact force control cases.

  12. Feedback Control of Floor Reaction Force Based on Force-Reflecting-Type Multilateral Control

    NASA Astrophysics Data System (ADS)

    Nagase, Kazuki; Katsura, Seiichiro

    Real-world haptics is being studied not only for improving feedback on real-world haptic information in teleoperation but also for developing key technologies for future human support. For the remote operating of systems at distant places, haptic information is required in addition to visual information. The haptic information around a work environment can be the floor reaction force, which can be obtained using a movement-type haptic device. The floor reaction force from the environment that the mobile haptic device touches is fed back accurately to the operator. First, this paper proposes a general force-reflecting-type multilateral control. Second, this paper extends the control to feedback control of the floor reaction force by using force-reflecting-type multilateral control and a novel haptic device employing a biped robot with a slave system. The position response of a master system is transformed to a leg tip position command for the biped-type haptic device. In addition, the floor reaction force determined by the biped-type haptic device is fed back to the master system. The proposed method can determine the force feedback to the sole of the foot, which is not possible with a conventional stationary system. As a result, the floor reaction force from a large area can be obtained, and the operability of the control system is improved by using the proposed system.

  13. 2. GENERAL VIEW OF SLC3 AIR FORCE BUILDING (BLDG. 761) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. GENERAL VIEW OF SLC-3 AIR FORCE BUILDING (BLDG. 761) FROM THE NORTHWEST - Vandenberg Air Force Base, Space Launch Complex 3, SLC-3 Air Force Building, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  14. 1. GENERAL VIEW OF SLC3 AIR FORCE BUILDING (BLDG. 761) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. GENERAL VIEW OF SLC-3 AIR FORCE BUILDING (BLDG. 761) FROM THE SOUTHWEST - Vandenberg Air Force Base, Space Launch Complex 3, SLC-3 Air Force Building, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  15. A novel reciprocating micropump based on Lorentz force

    NASA Astrophysics Data System (ADS)

    Salari, Alinaghi; Hakimsima, Abbas; Shafii, Mohammad Behshad

    2015-03-01

    Lorentz force is the pumping basis of many electromagnetic micropumps used in lab-on-a-chip. In this paper a novel reciprocating single-chamber micropump is proposed, in which the actuation technique is based on Lorentz force acting on an array of microwires attached on a membrane surface. An alternating current is applied through the microwires in the presence of a magnetic field. The resultant force causes the membrane to oscillate and pushes the fluid to flow through microchannel using a ball-valve. The pump chamber (3 mm depth) was fabricated on a Polymethylmethacrylate (PMMA) substrate using laser engraving technique. The chamber was covered by a 60 μm thick hyper-elastic latex rubber diaphragm. Two miniature permanent magnets capable of providing magnetic field of 0.09 T at the center of the diaphragm were mounted on each side of the chamber. Square wave electric current with low-frequencies was generated using a function generator. Cylindrical copper microwires (250 μm diameter and 5 mm length) were attached side-by-side on top surface of the diaphragm. Thin loosely attached wires were used as connectors to energize the electrodes. Due to large displacement length of the diaphragm (~3 mm) a high efficiency (~90%) ball valve (2 mm diameter stainless steel ball in a tapered tubing structure) was used in the pump outlet. The micropump exhibits a flow rate as high as 490 μl/s and pressure up to 1.5 kPa showing that the pump is categorized among high-flow-rate mechanical micropumps.

  16. Force-compensated hydrogel-based pH sensor

    NASA Astrophysics Data System (ADS)

    Deng, Kangfa; Gerlach, Gerald; Guenther, Margarita

    2015-04-01

    This paper presents the design, simulation, assembly and testing of a force-compensated hydrogel-based pH sensor. In the conventional deflection method, a piezoresistive pressure sensor is used as a chemical-mechanical-electronic transducer to measure the volume change of a pH-sensitive hydrogel. In this compensation method, the pH-sensitive hydrogel keeps its volume constant during the whole measuring process, independent of applied pH value. In order to maintain a balanced state, an additional thermal actuator is integrated into the close-loop sensor system with higher precision and faster dynamic response. Poly (N-isopropylacrylamide) (PNIPAAm) with 5 mol% monomer 3-acrylamido propionic acid (AAmPA) is used as the temperature-sensitive hydrogel, while poly (vinyl alcohol) with poly (acrylic acid) (PAA) serves as the pH-sensitive hydrogel. A thermal simulation is introduced to assess the temperature distribution of the whole microsystem, especially the temperature influence on both hydrogels. Following tests are detailed to verify the working functions of a sensor based on pH-sensitive hydrogel and an actuator based on temperature-sensitive hydrogel. A miniaturized prototype is assembled and investigated in deionized water: the response time amounts to about 25 min, just half of that one of a sensor based on the conventional deflection method. The results confirm the applicability of t he compensation method to the hydrogel-based sensors.

  17. Thermodynamic properties and atomic structure of Ca-based liquid alloys

    NASA Astrophysics Data System (ADS)

    Poizeau, Sophie

    To identify the most promising positive electrodes for Ca-based liquid metal batteries, the thermodynamic properties of diverse Ca-based liquid alloys were investigated. The thermodynamic properties of Ca-Sb alloys were determined by emf measurements. It was found that Sb as positive electrode would provide the highest voltage for Ca-based liquid metal batteries (1 V). The price of such a battery would be competitive for the grid-scale energy storage market. The impact of Pb, a natural impurity of Sb, was predicted successfully and confirmed via electrochemical measurements. It was shown that the impact on the open circuit voltage would be minor. Indeed, the interaction between Ca and Sb was demonstrated to be much stronger than between Ca and Pb using thermodynamic modeling, which explains why the partial thermodynamic properties of Ca would not vary much with the addition of Pb to Sb. However, the usage of the positive electrode would be reduced, which would limit the interest of a Pb-Sb positive electrode. Throughout this work, the molecular interaction volume model (MIVM) was used for the first time for alloys with thermodynamic properties showing strong negative deviation from ideality. This model showed that systems such as Ca-Sb have strong short-range order: Ca is most stable when its first nearest neighbors are Sb. This is consistent with what the more traditional thermodynamic model, the regular association model, would predict. The advantages of the MIVM are the absence of assumption regarding the composition of an associate, and the reduced number of fitting parameters (2 instead of 5). Based on the parameters derived from the thermodynamic modeling using the MIVM, a new potential of mixing for liquid alloys was defined to compare the strength of interaction in different Ca-based alloys. Comparing this trend with the strength of interaction in the solid state of these systems (assessed by the energy of formation of the intermetallics), the systems with

  18. 33 CFR 165.1102 - Security Zone; Naval Base Point Loma; San Diego Bay, CA.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Point A. (b) Regulations. (1) The general regulations governing security zones found in 33 CFR 165.33... a security zone: The water adjacent to the Naval Base Point Loma, San Diego, CA, enclosed by the... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Security Zone; Naval Base...

  19. High performance target measurement flights from Vandenberg Air Force Base

    NASA Astrophysics Data System (ADS)

    Chalfant, C. P.; Rosen, H.; Jerger, J. H.

    A description is presented of a new launch facility which is being prepared for the High Performance Target Measurement (HPTEM) booster at Vandenberg Air Force Base (VAFB). A deactivated Atlas launch complex is currently being modified to allow the rocket to be launched from a semisilo. The underground launch operations building will contain a new control center and instrumentation room. Attention is given to the Multi-Spectral Measurement Program (MSMP), details concerning the launch facility, and a target and flight safety trajectory analysis. Construction and modification of the facility is scheduled to be completed in mid-1983. The first HPTEM launch is planned to occur in April 1984. The HPTEM launch facility can also be utilized to launch Aries I (single stage) and Aries II (two-stage) probes with minor modification.

  20. STS-92 - Landing at Edwards Air Force Base

    NASA Technical Reports Server (NTRS)

    2000-01-01

    With its drag parachute deployed to help slow it down, the Space Shuttle Discovery rolls down the runway after landing at Edwards Air Force Base in Southern California at the conclusion of mission STS-92 on October 24, 2000. STS-92 was the 100th mission since the fleet of four Space Shuttles began flying in 1981. (Due to schedule changes, missions are not always launched in the order that was originally planned.) The almost 13-day mission, the 46th Shuttle mission to land at Edwards, was the last construction mission for the International Space Station prior to the first scientists taking up residency in the orbiting space laboratory the following month. The seven-member crew on STS-92 included mission specialists Koichi Wakata, Michael Lopez-Alegria, Jeff Wisoff, Bill McArthur and Leroy Chiao, pilot Pam Melroy and mission commander Brian Duffy.

  1. DETAIL, CONTROL BOOTH, RP1 TANK FARM Edwards Air Force ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL, CONTROL BOOTH, RP1 TANK FARM - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Combined Fuel Storage Tank Farm, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  2. 4. BUILDING 8767, INTERIOR. Looking west. Edwards Air Force ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. BUILDING 8767, INTERIOR. Looking west. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Observation Bunkers for Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  3. SOUTHEAST AND NORTHEAST SIDES. Looking west Edwards Air Force ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    SOUTHEAST AND NORTHEAST SIDES. Looking west - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Fuel & Water Tank, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

  4. Force feedback microscopy based on an optical beam deflection scheme

    NASA Astrophysics Data System (ADS)

    Vitorino, Miguel V.; Carpentier, Simon; Costa, Luca; Rodrigues, Mario S.

    2014-07-01

    Force feedback microscopy circumvents the jump to contact in atomic force microscopy when using soft cantilevers and quantitatively measures the interaction properties at the nanoscale by simultaneously providing force, force gradient, and dissipation. The force feedback microscope developed so far used an optical cavity to measure the tip displacement. In this Letter, we show that the more conventional optical beam deflection scheme can be used to the same purpose. With this instrument, we have followed the evolution of the Brownian motion of the tip under the influence of a water bridge.

  5. Force feedback microscopy based on an optical beam deflection scheme

    SciTech Connect

    Vitorino, Miguel V.; Rodrigues, Mario S.; Carpentier, Simon; Costa, Luca

    2014-07-07

    Force feedback microscopy circumvents the jump to contact in atomic force microscopy when using soft cantilevers and quantitatively measures the interaction properties at the nanoscale by simultaneously providing force, force gradient, and dissipation. The force feedback microscope developed so far used an optical cavity to measure the tip displacement. In this Letter, we show that the more conventional optical beam deflection scheme can be used to the same purpose. With this instrument, we have followed the evolution of the Brownian motion of the tip under the influence of a water bridge.

  6. Ca2+-driven intestinal HCO(3)(-) secretion and CaCO3 precipitation in the European flounder in vivo: influences on acid-base regulation and blood gas transport.

    PubMed

    Cooper, Christopher A; Whittamore, Jonathan M; Wilson, Rod W

    2010-04-01

    Marine teleost fish continuously ingest seawater to prevent dehydration and their intestines absorb fluid by mechanisms linked to three separate driving forces: 1) cotransport of NaCl from the gut fluid; 2) bicarbonate (HCO(3)(-)) secretion and Cl(-) absorption via Cl(-)/HCO(3)(-) exchange fueled by metabolic CO(2); and 3) alkaline precipitation of Ca(2+) as insoluble CaCO(3), which aids H(2)O absorption). The latter two processes involve high rates of epithelial HCO(3)(-) secretion stimulated by intestinal Ca(2+) and can drive a major portion of water absorption. At higher salinities and ambient Ca(2+) concentrations the osmoregulatory role of intestinal HCO(3)(-) secretion is amplified, but this has repercussions for other physiological processes, in particular, respiratory gas transport (as it is fueled by metabolic CO(2)) and acid-base regulation (as intestinal cells must export H(+) into the blood to balance apical HCO(3)(-) secretion). The flounder intestine was perfused in vivo with salines containing 10, 40, or 90 mM Ca(2+). Increasing the luminal Ca(2+) concentration caused a large elevation in intestinal HCO(3)(-) production and excretion. Additionally, blood pH decreased (-0.13 pH units) and plasma partial pressure of CO(2) (Pco(2)) levels were elevated (+1.16 mmHg) at the highest Ca perfusate level after 3 days of perfusion. Increasing the perfusate [Ca(2+)] also produced proportional increases in net acid excretion via the gills. When the net intestinal flux of all ions across the intestine was calculated, there was a greater absorption of anions than cations. This missing cation flux was assumed to be protons, which vary with an almost 1:1 relationship with net acid excretion via the gill. This study illustrates the intimate link between intestinal HCO(3)(-) production and osmoregulation with acid-base balance and respiratory gas exchange and the specific controlling role of ingested Ca(2+) independent of any other ion or overall osmolality in marine

  7. 33 CFR 165.1184 - Safety Zone; Coast Guard Use of Force Training Exercises, San Pablo Bay, CA.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Safety Zone; Coast Guard Use of... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY REGULATED NAVIGATION... Coast Guard District § 165.1184 Safety Zone; Coast Guard Use of Force Training Exercises, San Pablo...

  8. 33 CFR 165.1184 - Safety Zone; Coast Guard Use of Force Training Exercises, San Pablo Bay, CA.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Safety Zone; Coast Guard Use of... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY REGULATED NAVIGATION... Coast Guard District § 165.1184 Safety Zone; Coast Guard Use of Force Training Exercises, San Pablo...

  9. 33 CFR 165.1184 - Safety Zone; Coast Guard Use of Force Training Exercises, San Pablo Bay, CA.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Safety Zone; Coast Guard Use of... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY REGULATED NAVIGATION... Coast Guard District § 165.1184 Safety Zone; Coast Guard Use of Force Training Exercises, San Pablo...

  10. Vegetation studies on Vandenberg Air Force Base, California

    NASA Technical Reports Server (NTRS)

    Schmalzer, Paul A.; Hickson, Diana E.; Hinkle, C. Ross

    1988-01-01

    Vandenburg Air Force Base, located in coastal central California with an area of 98,400 ac, contains resources of considerable biological significance. Available information on the vegetation and flora of Vandenburg is summarized and new data collected in this project are presented. A bibliography of 621 references dealing with vegetation and related topics related to Vanderburg was compiled from computer and manual literature searches and a review of past studies of the base. A preliminary floristic list of 642 taxa representing 311 genera and 80 families was compiled from past studies and plants identified in the vegetation sampling conducted in this project. Fifty-two special interest plant species are known to occur or were suggested to occur. Vegetation was sampled using permanent plots and transects in all major plant communities including chaparral, Bishop pine forest, tanbark oak forest, annual grassland, oak woodland, coastal sage scrub, purple sage scrub, coastal dune scrub, coastal dunes, box elder riparian woodland, will riparian woodland, freshwater marsh, salt marsh, and seasonal wetlands. Comparison of the new vegetation data to the compostie San Diego State University data does not indicate major changes in most communities since the original study. Recommendations are made for additional studies needed to maintain and extend the environmental data base and for management actions to improve resource protection.

  11. Sitewide feasibility study Eielson Air Force Base, Alaska

    SciTech Connect

    Last, G.V.; Lanigan, D.C.; Josephson, G.B.; Bagaasen, L.M.

    1995-09-01

    The Sitewide Feasibility Study (FS) is required under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), the National Contingency Plan (NCP), and the Federal Facility Agreement (FFA) for Eielson Air Force Base (AFB). It is based on findings presented in the Sitewide Remedial Investigation (RI) Report (USAF 1995a), and the Sitewide Baseline Risk Assessment (BLRA) Report (USAF 1995b). Under the FFA, 64 potential source areas were placed in one of six operable units, based on similar contaminant and environmental characteristics, or were included for evaluation under a Source Evaluation Report (SER). The sitewide RI was directed at contamination that was not confined to an operable unit (OU) or SER source area. The objectives of the sitewide RI were to: Provide information about site characteristics to support individual OU RI/FS efforts and the sitewide RI/FS, including site hydrogeology and determination of background soil and groundwater characteristics; identify and characterize contamination that is not confined or attributable to a specific source area through sitewide monitoring of groundwater and surface water; evaluate cumulative risks to human health and the environment from contamination on a sitewide basis; and provide a mechanism for continued cohesive sitewide monitoring.

  12. Review of wildlife resources of Vandenberg Air Force Base, California

    NASA Technical Reports Server (NTRS)

    Breininger, David R.

    1989-01-01

    Wildlife resources are reviewed for purposes of developing a Base Biological Monitoring Program (BMP) for Vandenberg Air Force Base (VAFB) in Santa Barbara County, California. The review and recommendations were prepared by review of applicable scientific literature and environmental documents for VAFB, discussing information needs with natural resource management professionals at VAFB, and observations of base field conditions. This process found that there are 29 federally listed vertebrates (endangered, threatened, or Category 2) that occur or may occur in the vicinity of VAFB. There are also 63 other state listed or regionally declining species that may occur in the vicinity of VAFB. Habitats of VAFB represent a very valuable environmental resource for rare and declining wildlife in California. However, little information is available on VAFB wildlife resources other than lists of species that occur or are expected to occur. Recommendations are presented to initiate a long-term wildlife monitoring program at VAFB to provide information for environmental impact assessment and wise land use planning.

  13. History of wildland fires on Vandenberg Air Force Base, California

    NASA Technical Reports Server (NTRS)

    Hickson, Diana E.

    1988-01-01

    The fire history of the past 50 years for Vandenberg AFB, California was determined using aerial photography, field investigation, and historical and current written records. This constitutes a record of the vegetation age classes for the entire base. The location, cause, and fuel type for sixty fires from this time period were determined. The fires were mapped and entered into a geographic infomation system (GIS) for Vandenberg. Fire history maps derived from this GIS were printed at 1:9600 scale and are on deposit at the Vandenberg Environmental Task Force Office. Although some ecologically significant plant communities on Vandenberg are adapted to fire, no natural fire frequency could be determined, since only one fire possibly caused by lightning occurred in the area now within the base since 1937. Observations made during this study suggest that burning may encourage the invasion of exotic species into chaparral, in particular Burton Mesa or sandhill chaparral, an unusual and geographically limited form of chaparral found on the base.

  14. Direct determination of the local Hamaker constant of inorganic surfaces based on scanning force microscopy

    SciTech Connect

    Krajina, Brad A.; Kocherlakota, Lakshmi S.; Overney, René M.

    2014-10-28

    The energetics involved in the bonding fluctuations between nanometer-sized silicon dioxide (SiO{sub 2}) probes and highly oriented pyrolytic graphite (HOPG) and molybdenum disulfide (MoS{sub 2}) could be quantified directly and locally on the submicron scale via a time-temperature superposition analysis of the lateral forces between scanning force microscopy silicon dioxide probes and inorganic sample surfaces. The so-called “intrinsic friction analysis” (IFA) provided direct access to the Hamaker constants for HOPG and MoS{sub 2}, as well as the control sample, calcium fluoride (CaF{sub 2}). The use of scanning probe enables nanoscopic analysis of bonding fluctuations, thereby overcoming challenges associated with larger scale inhomogeneity and surface roughness common to conventional techniques used to determine surface free energies and dielectric properties. A complementary numerical analysis based on optical and electron energy loss spectroscopy and the Lifshitz quantum electrodynamic theory of van der Waals interactions is provided and confirms quantitatively the IFA results.

  15. ROS-Mediated Decline in Maximum Ca2+-Activated Force in Rat Skeletal Muscle Fibers following In Vitro and In Vivo Stimulation

    PubMed Central

    Dutka, Travis L.; Verburg, Esther; Larkins, Noni; Hortemo, Kristin H.; Lunde, Per K.; Sejersted, Ole M.; Lamb, Graham D.

    2012-01-01

    We hypothesised that normal skeletal muscle stimulated intensely either in vitro or in situ would exhibit reactive oxygen species (ROS)-mediated contractile apparatus changes common to many pathophysiological conditions. Isolated soleus (SOL) and extensor digitorum longus (EDL) muscles of the rat were bubbled with 95% O2 and stimulated in vitro at 31°C to give isometric tetani (50 Hz for 0.5 s every 2 s) until maximum force declined to ≤30%. Skinned superficial slow-twitch fibers from the SOL muscles displayed a large reduction (∼41%) in maximum Ca2+-activated specific force (Fmax), with Ca2+-sensitivity unchanged. Fibers from EDL muscles were less affected. The decrease in Fmax in SOL fibers was evidently due to oxidation effects on cysteine residues because it was reversed if the reducing agent DTT was applied prior to activating the fiber. The GSH∶GSSG ratio was ∼3-fold lower in the cytoplasm of superficial fibers from stimulated muscle compared to control, confirming increased oxidant levels. The presence of Tempol and L-NAME during in vitro stimulation prevented reduction in Fmax. Skinned fibers from SOL muscles stimulated in vivo at 37°C with intact blood supply also displayed reduction in Fmax, though to a much smaller extent (∼12%). Thus, fibers from muscles stimulated even with putatively adequate O2 supply display a reversible oxidation-induced decrease in Fmax without change in Ca2+-sensitivity, consistent with action of peroxynitrite (or possibly superoxide) on cysteine residues of the contractile apparatus. Significantly, the changes closely resemble the contractile deficits observed in a range of pathophysiological conditions. These findings highlight how readily muscle experiences ROS-related deficits, and also point to potential difficulties when defining muscle performance and fatigue. PMID:22629297

  16. ROS-mediated decline in maximum Ca2+-activated force in rat skeletal muscle fibers following in vitro and in vivo stimulation.

    PubMed

    Dutka, Travis L; Verburg, Esther; Larkins, Noni; Hortemo, Kristin H; Lunde, Per K; Sejersted, Ole M; Lamb, Graham D

    2012-01-01

    We hypothesised that normal skeletal muscle stimulated intensely either in vitro or in situ would exhibit reactive oxygen species (ROS)-mediated contractile apparatus changes common to many pathophysiological conditions. Isolated soleus (SOL) and extensor digitorum longus (EDL) muscles of the rat were bubbled with 95% O(2) and stimulated in vitro at 31°C to give isometric tetani (50 Hz for 0.5 s every 2 s) until maximum force declined to ≤30%. Skinned superficial slow-twitch fibers from the SOL muscles displayed a large reduction (∼41%) in maximum Ca(2+)-activated specific force (F(max)), with Ca(2+)-sensitivity unchanged. Fibers from EDL muscles were less affected. The decrease in F(max) in SOL fibers was evidently due to oxidation effects on cysteine residues because it was reversed if the reducing agent DTT was applied prior to activating the fiber. The GSH:GSSG ratio was ∼3-fold lower in the cytoplasm of superficial fibers from stimulated muscle compared to control, confirming increased oxidant levels. The presence of Tempol and L-NAME during in vitro stimulation prevented reduction in F(max). Skinned fibers from SOL muscles stimulated in vivo at 37°C with intact blood supply also displayed reduction in F(max), though to a much smaller extent (∼12%). Thus, fibers from muscles stimulated even with putatively adequate O(2) supply display a reversible oxidation-induced decrease in F(max) without change in Ca(2+)-sensitivity, consistent with action of peroxynitrite (or possibly superoxide) on cysteine residues of the contractile apparatus. Significantly, the changes closely resemble the contractile deficits observed in a range of pathophysiological conditions. These findings highlight how readily muscle experiences ROS-related deficits, and also point to potential difficulties when defining muscle performance and fatigue. PMID:22629297

  17. Acoustic Radiation Force Impulse (ARFI) Imaging-Based Needle Visualization

    PubMed Central

    Rotemberg, Veronica; Palmeri, Mark; Rosenzweig, Stephen; Grant, Stuart; Macleod, David; Nightingale, Kathryn

    2011-01-01

    Ultrasound-guided needle placement is widely used in the clinical setting, particularly for central venous catheter placement, tissue biopsy and regional anesthesia. Difficulties with ultrasound guidance in these areas often result from steep needle insertion angles and spatial offsets between the imaging plane and the needle. Acoustic Radiation Force Impulse (ARFI) imaging leads to improved needle visualization because it uses a standard diagnostic scanner to perform radiation force based elasticity imaging, creating a displacement map that displays tissue stiffness variations. The needle visualization in ARFI images is independent of needle-insertion angle and also extends needle visibility out of plane. Although ARFI images portray needles well, they often do not contain the usual B-mode landmarks. Therefore, a three-step segmentation algorithm has been developed to identify a needle in an ARFI image and overlay the needle prediction on a coregistered B-mode image. The steps are: (1) contrast enhancement by median filtration and Laplacian operator filtration, (2) noise suppression through displacement estimate correlation coefficient thresholding and (3) smoothing by removal of outliers and best-fit line prediction. The algorithm was applied to data sets from horizontal 18, 21 and 25 gauge needles between 0–4 mm offset in elevation from the transducer imaging plane and to 18G needles on the transducer axis (in plane) between 10° and 35° from the horizontal. Needle tips were visualized within 2 mm of their actual position for both horizontal needle orientations up to 1.5 mm off set in elevation from the transducer imaging plane and on-axis angled needles between 10°–35° above the horizontal orientation. We conclude that segmented ARFI images overlaid on matched B-mode images hold promise for improved needle visibility in many clinical applications. PMID:21608445

  18. Towards a force field based on density fitting

    PubMed Central

    Piquemal, Jean-Philip; Cisneros, G. Andrés; Reinhardt, Peter; Gresh, Nohad; Darden, Thomas A.

    2007-01-01

    Total intermolecular interaction energies are determined with a first version of the Gaussian electrostatic model (GEM-0), a force field based on a density fitting approach using s-type Gaussian functions. The total interaction energy is computed in the spirit of the sum of interacting fragment ab initio (SIBFA) force field by separately evaluating each one of its components: electrostatic (Coulomb), exchange repulsion, polarization, and charge transfer intermolecular interaction energies, in order to reproduce reference constrained space orbital variation (CSOV) energy decomposition calculations at the B3LYP/aug-cc-pVTZ level. The use of an auxiliary basis set restricted to spherical Gaussian functions facilitates the rotation of the fitted densities of rigid fragments and enables a fast and accurate density fitting evaluation of Coulomb and exchange-repulsion energy, the latter using the overlap model introduced by Wheatley and Price [Mol. Phys. 69, 50718 (1990)]. The SIBFA energy scheme for polarization and charge transfer has been implemented using the electric fields and electrostatic potentials generated by the fitted densities. GEM-0 has been tested on ten stationary points of the water dimer potential energy surface and on three water clusters (n=16,20,64). The results show very good agreement with density functional theory calculations, reproducing the individual CSOV energy contributions for a given interaction as well as the B3LYP total interaction energies with errors below kBT at room temperature. Preliminary results for Coulomb and exchange-repulsion energies of metal cation complexes and coupled cluster singles doubles electron densities are discussed. PMID:16542062

  19. A novel aptasensor based on single-molecule force spectroscopy for highly sensitive detection of mercury ions.

    PubMed

    Li, Qing; Michaelis, Monika; Wei, Gang; Colombi Ciacchi, Lucio

    2015-08-01

    We have developed a novel aptasensor based on single-molecule force spectroscopy (SMFS) capable of detecting mercury ions (Hg(2+)) with sub-nM sensitivity. The single-strand (ss) DNA aptamer used in this work is rich in thymine (T) and readily forms T-Hg(2+)-T complexes in the presence of Hg(2+). The aptamer was conjugated to an atomic force microscope (AFM) probe, and the adhesion force between the probe and a flat graphite surface was measured by single-molecule force spectroscopy (SMFS). The presence of Hg(2+) ions above a concentration threshold corresponding to the affinity constant of the ions for the aptamer (about 5 × 10(9) M(-1)) could be easily detected by a change of the measured adhesion force. With our chosen aptamer, we could reach an Hg(2+) detection limit of 100 pM, which is well below the maximum allowable level of Hg(2+) in drinking water. In addition, this aptasensor presents a very high selectivity for Hg(2+) over other metal cations, such as K(+), Ca(2+), Zn(2+), Fe(2+), and Cd(2+). Furthermore, the effects of the ionic strength and loading rate on the Hg(2+) detection were evaluated. Its simplicity, reproducibility, high selectivity and sensitivity make our SMFS-based aptasensor advantageous with respect to other current Hg(2+) sensing methods. It is expected that our strategy can be exploited for monitoring the pollution of water environments and the safety of potentially contaminated food. PMID:26075518

  20. 8. Credit USAF, ca. 1945. Original housed in the Muroc ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Credit USAF, ca. 1945. Original housed in the Muroc Flight Test Base, Unit History, 1 September 1942 - 30 June 1945. Alfred F. Simpson Historical Research Agency. United States Air Force. Maxwell AFB, Alabama. View of concrete base for jet engine rotor balancing machine. Location where photograph was taken not determined, but presumed to be in shops of Building 4505 which had a sizeable machine shop. - Edwards Air Force Base, North Base, Hangar, End of North Base Road, Boron, Kern County, CA

  1. 9. Credit USAF, ca. 1945. Original housed in the Muroc ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. Credit USAF, ca. 1945. Original housed in the Muroc Flight Test Base, Unit History, 1 September 1942 - 30 June 1945. Alfred F. Simpson Historical Research Agency. United States Air Force. Maxwell AFB, Alabama. View of concrete base and brackets of jet engine rotor balancing machine. Location where photograph was taken not determined, but presumed to be in shops of Building 4505. - Edwards Air Force Base, North Base, Hangar, End of North Base Road, Boron, Kern County, CA

  2. 33 CFR 334.560 - Banana River at Patrick Air Force Base, Fla.; restricted area.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Banana River at Patrick Air Force... River at Patrick Air Force Base, Fla.; restricted area. (a) The area. The waters within an area... Commander, 45th Space Wing, Patrick Air Force Base, Florida, and such agencies as he/she may designate....

  3. 33 CFR 334.560 - Banana River at Patrick Air Force Base, Fla.; restricted area.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Banana River at Patrick Air Force... River at Patrick Air Force Base, Fla.; restricted area. (a) The area. The waters within an area... Commander, 45th Space Wing, Patrick Air Force Base, Florida, and such agencies as he/she may designate....

  4. 33 CFR 165.768 - Security Zone; MacDill Air Force Base, Tampa Bay, FL.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Security Zone; MacDill Air Force....768 Security Zone; MacDill Air Force Base, Tampa Bay, FL. (a) Location. The following area is a... title. All waters within Tampa Bay, Florida in the vicinity of MacDill Air Force Base,...

  5. 33 CFR 334.560 - Banana River at Patrick Air Force Base, Fla.; restricted area.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Banana River at Patrick Air Force... River at Patrick Air Force Base, Fla.; restricted area. (a) The area. The waters within an area... Commander, 45th Space Wing, Patrick Air Force Base, Florida, and such agencies as he/she may designate....

  6. 33 CFR 165.768 - Security Zone; MacDill Air Force Base, Tampa Bay, FL.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Security Zone; MacDill Air Force....768 Security Zone; MacDill Air Force Base, Tampa Bay, FL. (a) Location. The following area is a... title. All waters within Tampa Bay, Florida in the vicinity of MacDill Air Force Base,...

  7. 33 CFR 165.768 - Security Zone; MacDill Air Force Base, Tampa Bay, FL.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone; MacDill Air Force....768 Security Zone; MacDill Air Force Base, Tampa Bay, FL. (a) Location. The following area is a... title. All waters within Tampa Bay, Florida in the vicinity of MacDill Air Force Base,...

  8. 33 CFR 334.560 - Banana River at Patrick Air Force Base, Fla.; restricted area.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Banana River at Patrick Air Force... River at Patrick Air Force Base, Fla.; restricted area. (a) The area. The waters within an area... Commander, 45th Space Wing, Patrick Air Force Base, Florida, and such agencies as he/she may designate....

  9. 33 CFR 165.768 - Security Zone; MacDill Air Force Base, Tampa Bay, FL.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Security Zone; MacDill Air Force....768 Security Zone; MacDill Air Force Base, Tampa Bay, FL. (a) Location. The following area is a... title. All waters within Tampa Bay, Florida in the vicinity of MacDill Air Force Base,...

  10. 33 CFR 165.768 - Security Zone; MacDill Air Force Base, Tampa Bay, FL.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Security Zone; MacDill Air Force....768 Security Zone; MacDill Air Force Base, Tampa Bay, FL. (a) Location. The following area is a... title. All waters within Tampa Bay, Florida in the vicinity of MacDill Air Force Base,...

  11. 33 CFR 334.560 - Banana River at Patrick Air Force Base, Fla.; restricted area.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Banana River at Patrick Air Force... River at Patrick Air Force Base, Fla.; restricted area. (a) The area. The waters within an area... Commander, 45th Space Wing, Patrick Air Force Base, Florida, and such agencies as he/she may designate....

  12. Impact of thermal frequency drift on highest precision force microscopy using quartz-based force sensors at low temperatures.

    PubMed

    Pielmeier, Florian; Meuer, Daniel; Schmid, Daniel; Strunk, Christoph; Giessibl, Franz J

    2014-01-01

    In frequency modulation atomic force microscopy (FM-AFM) the stability of the eigenfrequency of the force sensor is of key importance for highest precision force measurements. Here, we study the influence of temperature changes on the resonance frequency of force sensors made of quartz, in a temperature range from 4.8-48 K. The sensors are based on the qPlus and length extensional principle. The frequency variation with temperature T for all sensors is negative up to 30 K and on the order of 1 ppm/K, up to 13 K, where a distinct kink appears, it is linear. Furthermore, we characterize a new type of miniaturized qPlus sensor and confirm the theoretically predicted reduction in detector noise. PMID:24778967

  13. Force-Based Reasoning for Assembly Planning and Subassembly Stability Analysis

    NASA Technical Reports Server (NTRS)

    Lee, S.; Yi, C.; Wang, F-C.

    1993-01-01

    In this paper, we show that force-based reasoning, for identifying a cluster of parts that can be decomposed naturally by the applied force, plays an important role in selecting feasible subassemblies and analyzing subassembly stability in assembly planning.

  14. A voice coil motor based measuring force control system for tactile scanning profiler

    NASA Astrophysics Data System (ADS)

    Feng, Shengdong; Liu, Xiaojun; Chen, Liangzhou; Zhou, Liping; Lu, Wenlong

    2015-02-01

    In tactile scanning profiler, the measuring force would change in a wide range when it was used for profile measurement in a large range, which could possibly destroy the measured surface. To solve the problem, measuring force control system for tactile scanning profiler was needed. In the paper, a voice coil motor-based measuring force control system for tactile scanning profiler was designed. In the design, a low stiffness coefficient spring was used to provide contact force, while a voice coil motor (VCM) to balance the spring force so that the contact force could be kept for constant measuring force. A VCM was designed specially, and for active measuring force control, a precision current source circuit under the control of a DSP unit was designed to drive the VCM. The performance of voice coil motor based measuring force control system had been tested, and its good characteristics were verified.

  15. Optical fiber-based force transducer for microscale samples.

    PubMed

    Seshagiri Rao, R V; Kalelkar, Chirag; Pullarkat, Pramod A

    2013-10-01

    We discuss the design, instrumentation, and calibration of a versatile force transducer with feedback control, called the Micro-Extensional Rheometer (MER). A force range of eight decades (1-10(8) pN) and a displacement range of four decades (10-10(5) nm) with a spatial resolution of the order of nanometers are accessible with the instrument. A feedback-loop algorithm is used to control the commanded force or the extensional strain on the sample and implement different rheometric protocols such as step-strain, step-force, exponential strain, among others. The device may also be used to measure the forces exerted by active suspensions, pulling neurons, etc. PMID:24182163

  16. Ligand-based virtual screening interface between PyMOL and LiSiCA.

    PubMed

    Dilip, Athira; Lešnik, Samo; Štular, Tanja; Janežič, Dušanka; Konc, Janez

    2016-01-01

    Ligand-based virtual screening of large small-molecule databases is an important step in the early stages of drug development. It is based on the similarity principle and is used to reduce the chemical space of large databases to a manageable size where chosen ligands can be experimentally tested. Ligand-based virtual screening can also be used to identify bioactive molecules with different basic scaffolds compared to already known bioactive molecules, thus having the potential to increase the structural variability of compounds. Here, we present an interface between the popular molecular graphics system PyMOL and the ligand-based virtual screening software LiSiCA available at http://insilab.org/lisica-plugin and demonstrate how this interface can be used in the early stages of drug discovery process.Graphical AbstractLigand-based virtual screening interface between PyMOL and LiSiCA. PMID:27606012

  17. An alternative method for immediate dose estimation using CaSO4:Dy based TLD badges

    NASA Astrophysics Data System (ADS)

    Singh, A. K.; Menon, S. N.; Dhabekar, Bhushan; Kadam, Sonal; Chougaonkar, M. P.; Babu, D. A. R.

    2014-11-01

    CaSO4:Dy based Thermoluminescence dosimeters (TLDs) are being used in country wide personnel monitoring program in India. The TL glow curve of CaSO4:Dy consists of a dosimetric peak at 220 °C and a low temperature peak at 120 °C which is unstable at room temperature. The TL integral counts in CaSO4:Dy reduces by 15% in seven days after irradiation due to the thermal fading of 120 °C TL peak. As the dosimetric procedure involves total integrated counts for dose conversion, the dosimeters are typically read about a week after receiving. However in the event of a suspected over exposure, where urgent processing is expected, this poses limitation. Post irradiation annealing treatment is used in such cases of immediate readout of cards. In this paper we report a new and easier to use technique based on optical bleaching for the urgent processing of TLD cards. Optical bleaching with green LED (∼555 nm photons) of 25,000 lux for one and half hour removes the low temperature TL peak without affecting the dosimetric peak. This method can be used for immediate dose estimation using CaSO4:Dy based TLD badges.

  18. Evaluation of the genotoxicity and mutagenicity of Ca3SiO5-based cement.

    PubMed

    Nai, Gisele Alborghetti; Logar, Gustavo de Almeida; Mori, Graziela Garrido; Teixeira, Ligia Moraes; Silva, Bruna Camila Ferreira da; Moraes, Ana Elisa Maranho de; Cabral, Felipe André

    2016-01-01

    Ca3SiO5 is new cement based on the composition of Portland that has been developed to have superior physicochemical and biological properties. In a clinical evaluation, the cement did not appear to have cytotoxic properties and allowed for the proliferation of pulp cells and gingival fibroblasts. However, no previous studies have evaluated the genotoxicity or the mutagenicity of Ca3SiO5in vivo. Therefore, the goal of this study is to evaluate the genotoxic and mutagenic potential of Ca3SiO5-based cement in vivo. Twenty-four male Wistar rats were divided into 3 groups (n = 8). Group A rats received subcutaneous implantation of Ca3SiO5 in the dorsum. Group B rats received a single dose of cyclophosphamide (positive control). Group C rats received subcutaneous implantation of empty tubes in the dorsum (negative control). After 24 hours, all animals were euthanized and the bone marrow of the femurs was collected for use in the comet assay and the micronucleus test. The comet assay revealed that the Ca3SiO5 group had a tail intensity of 23.57 ± 7.70%, the cyclophosphamide group had a tail intensity of 27.43 ± 7.40%, and the negative control group had a tail intensity of 24.75 ± 5.55%. The average number of micronuclei was 6.25 (standard deviation, SD = 3.53) in the Ca3SiO5 group, 9.75 (SD = 2.49) in the cyclophosphamide group, and 0.75 (SD = 1.03) in the negative control group. There was an increase in the micronuclei frequency in the Ca3SiO5 group compared to that of the negative control group (p < 0.05). Our data showed that exposure to the Ca3SiO5-based cement resulted in an increase in the frequency of micronuclei, but no genotoxicity was detected according to the comet assay. PMID:27556557

  19. "Galileo's Machine": Late Notes on Free Fall, Projectile Motion, and the Force of Percussion (ca. 1638-1639)

    NASA Astrophysics Data System (ADS)

    Salvia, Stefano

    2014-12-01

    My paper focuses upon the problem of determining the nature, establishing the proportionality, and measuring the intensity of the force of percussion of a projected or falling body, as treated in the Sixth Day of Galileo's Discorsi e dimostrazioni matematiche intorno a due nuove scienze (1638). This fragment was written around 1638-1639 as part of two additional Days of the Discorsi, which Galileo never finished and remained unpublished until 1718. Galileo's last works on percussion show a significant step towards a generalization of his own views on uniform and accelerated motion that will later lead to the Newtonian principle of inertia. The experiment with two equal weights hanging on a pulley, performed in Arcetri during the same period, is compared with the Paduan 1604-1608 experience of the "water balance." Both account for more than three decades of inquiries into what Galileo called forza della percossa, which marked the transition from preclassical to classical mechanics.

  20. An analysis of rumor propagation based on propagation force

    NASA Astrophysics Data System (ADS)

    Zhao, Zhen-jun; Liu, Yong-mei; Wang, Ke-xi

    2016-02-01

    A propagation force is introduced into the analysis of rumor propagation to address uncertainty in the process. The propagation force is portrayed as a fuzzy variable, and a category of new parameters with fuzzy variables is defined. The classic susceptible, infected, recovered (SIR) model is modified using these parameters, a fuzzy reproductive number is introduced into the modified model, and the rationality of the fuzzy reproductive number is illuminated through calculation and comparison. Rumor control strategies are also discussed.

  1. Credit USAF, ca. 1945. Original housed in the Photograph Files, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Credit USAF, ca. 1945. Original housed in the Photograph Files, AFFTC/HO, Edwards AFB, California. Early view of the Control Tower (designated T-65, Building 4500) fitted out with radio antennae. Structure at base of tower was T42 (later Building 4503), Flight Operations - Edwards Air Force Base, North Base, Radio & Control Tower T-65, Northeast of A Street, Boron, Kern County, CA

  2. Chiral EFT based nuclear forces: achievements and challenges

    NASA Astrophysics Data System (ADS)

    Machleidt, R.; Sammarruca, F.

    2016-08-01

    During the past two decades, chiral effective field theory has become a popular tool to derive nuclear forces from first principles. Two-nucleon interactions have been worked out up to sixth order of chiral perturbation theory and three-nucleon forces up to fifth order. Applications of some of these forces have been conducted in nuclear few- and many-body systems—with a certain degree of success. But in spite of these achievements, we are still faced with great challenges. Among them is the issue of a proper uncertainty quantification of predictions obtained when applying these forces in ab initio calculations of nuclear structure and reactions. A related problem is the order by order convergence of the chiral expansion. We start this review with a pedagogical introduction and then present the current status of the field of chiral nuclear forces. This is followed by a discussion of representative examples for the application of chiral two- and three-body forces in the nuclear many-body system including convergence issues.

  3. Probing biofouling resistant polymer brush surfaces by atomic force microscopy based force spectroscopy.

    PubMed

    Schön, Peter; Kutnyanszky, Edit; ten Donkelaar, Bas; Santonicola, M Gabriella; Tecim, Tugba; Aldred, Nick; Clare, Anthony S; Vancso, G Julius

    2013-02-01

    The protein repellency and biofouling resistance of zwitterionic poly(sulfobetaine methacrylate)(pSBMA) brushes grafted via surface initiated polymerization (SIP) from silicon and glass substrata was assessed using atomic force microscopy (AFM) adherence experiments. Laboratory settlement assays were conducted with cypris larvae of the barnacle Balanus amphitrite. AFM adherence includes the determination of contact rupture forces when AFM probe tips are withdrawn from the substratum. When the surface of the AFM tip is modified, adherence can be assessed with chemical specifity using a method known as chemical force microscopy (CFM). In this study, AFM tips were chemically functionalized with (a) fibronectin- here used as model for a nonspecifically adhering protein - and (b) arginine-glycine-aspartic acid (RGD) peptide motifs covalently attached to poly(methacrylic acid) (PMAA) brushes as biomimics of cellular adhesion receptors. Fibronectin functionalized tips showed significantly reduced nonspecific adhesion to pSBMA-modified substrata compared to bare gold (2.3±0.75 nN) and octadecanethiol (ODT) self-assembled monolayers (1.3±0.75 nN). PMAA and PMAA-RGD modified probes showed no significant adhesion to pSBMA modified silicon substrata. The results gathered through AFM protein adherence studies were complemented by laboratory fouling studies, which showed no adhesion of cypris larvae of Balanus amphitrite on pSBMA. With regard to its unusually high non-specific adsorption to a wide variety of materials the behavior of fibronectin is analogous to the barnacle cyprid temporary adhesive that also binds well to surfaces differing in polarity, charge and free energy. The antifouling efficacy of pSBMA may, therefore, be directly related to the ability of this surface to resist nonspecific protein adsorption. PMID:23138001

  4. Problem-Based Learning in 9th Grade Chemistry Class: "Intermolecular Forces"

    ERIC Educational Resources Information Center

    Tarhan, Leman; Ayar-Kayali, Hulya; Urek, Raziye Ozturk; Acar, Burcin

    2008-01-01

    This research study aims to examine the effectiveness of a problem-based learning (PBL) on 9th grade students' understanding of intermolecular forces (dipole-dipole forces, London dispersion forces and hydrogen bonding). The student's alternate conceptions about intermolecular bonding and their beliefs about PBL were also measured. Seventy-eight…

  5. FRET-Based Nanobiosensors for Imaging Intracellular Ca2+ and H+ Microdomains

    PubMed Central

    Zamaleeva, Alsu I.; Despras, Guillaume; Luccardini, Camilla; Collot, Mayeul; de Waard, Michel; Oheim, Martin; Mallet, Jean-Maurice; Feltz, Anne

    2015-01-01

    Semiconductor nanocrystals (NCs) or quantum dots (QDs) are luminous point emitters increasingly being used to tag and track biomolecules in biological/biomedical imaging. However, their intracellular use as highlighters of single-molecule localization and nanobiosensors reporting ion microdomains changes has remained a major challenge. Here, we report the design, generation and validation of FRET-based nanobiosensors for detection of intracellular Ca2+ and H+ transients. Our sensors combine a commercially available CANdot®565QD as an energy donor with, as an acceptor, our custom-synthesized red-emitting Ca2+ or H+ probes. These ‘Rubies’ are based on an extended rhodamine as a fluorophore and a phenol or BAPTA (1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetra-acetic acid) for H+ or Ca2+ sensing, respectively, and additionally bear a linker arm for conjugation. QDs were stably functionalized using the same SH/maleimide crosslink chemistry for all desired reactants. Mixing ion sensor and cell-penetrating peptides (that facilitate cytoplasmic delivery) at the desired stoichiometric ratio produced controlled multi-conjugated assemblies. Multiple acceptors on the same central donor allow up-concentrating the ion sensor on the QD surface to concentrations higher than those that could be achieved in free solution, increasing FRET efficiency and improving the signal. We validate these nanosensors for the detection of intracellular Ca2+ and pH transients using live-cell fluorescence imaging. PMID:26404317

  6. Role of hydrogen in the electronic properties of CaFeAsH-based superconductors

    NASA Astrophysics Data System (ADS)

    Huang, Y. N.; Liu, D. Y.; Zou, L. J.; Pickett, W. E.

    2016-05-01

    The electronic and magnetic properties of the hydride superconductor CaFeAsH, which superconducts up to 47 K when electron doped with La, and the isovalent alloy system CaFeAsH1 -xFx are investigated using density functional based methods. The Q ⃗=(π ,π ,0 ) peak of the nesting function ξ (q ⃗) is found to be extremely strong and sharp, and the additional structure in ξ (q ⃗) associated with the near-circular Fermi surfaces (FSs) that may impact low energy excitations is quantified. The unusual band introduced by H, which shows strong dispersion perpendicular to the FeAs layers, is shown to be connected to a peculiar van Hove singularity just below the Fermi level. This band provides a three-dimensional electron ellipsoid Fermi surface not present in other Fe-based superconducting materials nor in CaFeAsF. Electron doping by 25% La or Co has a minor effect on this ellipsoid Fermi surface, but suppresses FS nesting strongly, consistent with the viewpoint that eliminating strong nesting and the associated magnetic order allows high Tc superconductivity to emerge. Various aspects of the isovalent alloy system CaFeAsH1 -xFx and means of electron doping are discussed in terms of influence of incipient bands.

  7. Studies of Surface morphology and Atomic Force Microscope-induced Surface Modifications in Calcium Manganese Oxide (CaMnO) Thin Films

    NASA Astrophysics Data System (ADS)

    Johnson, Anthony; Hart, Cacie; Chaudhry, Adeel; Lawson, Bridget; Ferrone, Natalie; Neubauer, Samuel; Houston, David; Kolagani, Rajeswari; Schaefer, David

    CaMnOis a material of interest for applications as a catalyst for renewable energy applications. Our recent work on epitaxial thin films of this material has shown that films with a tensile lattice mismatch strain exhibit structural and electrical properties that indicate oxygen deficiency. We are studying the influence of strain and oxygen stoichiometry variations on surface morphology as revealed by atomic force microscopy. Our previous work in epitaxial thin films of the hole doped manganite nanoscale has demonstrated surface modifications induced by a voltage-biased AFM tip. Such surface modifications have been shown to be associated with changes in cation and oxygen stoichiometry. We will report results of similar studies on strained CaMnOthin films; relevant for understanding the surface mobility of oxygen vacancies. We acknowledge support from the Towson Office of University Undergraduate Research, Fisher Endowment Grant and Undergraduate Research Grant from the Fisher College of Science and Mathematics, and Seed Funding Grant from the School of Emerging technologies.

  8. Effects of trichloroethylene and perchloroethylene on wild rodents at Edwards Air Force Base, California, USA

    USGS Publications Warehouse

    Spring, S.E.; Miles, A.K.; Anderson, M.J.

    2004-01-01

    Effects of inhalation of volatilized trichloroethylene (TCE) or perchloroethylene (PCE) were assessed based on the health and population size of wild, burrowing mammals at Edwards Air Force Base (CA, USA). Organic soil-vapor concentrations were measured at three sites with aquifer contamination of TCE or PCE of 5.5 to 77 mg/L and at two uncontaminated reference sites. Population estimates of kangaroo rats (Dipodomys merriami and D. panamintinus) as well as hematology, blood chemistry, and histopathology of kangaroo rats and deer mice (Peromyscus maniculatus) were compared between contaminated and uncontaminated populations. Maximum soil-gas concentrations associated with groundwater contamination were less than 1.5 ??l/L of TCE and 0.07 ??l/L of PCE. Population estimates of kangaroo rats were similar at contaminated and reference sites. Hematology, blood chemistry, and histopathology of kangaroo rats and deer mice indicated no evidence of health effects caused by exposure. Trichloroethylene or PCE in groundwater and in related soil gas did not appear to reduce the size of small mammal populations or impair the health of individuals.

  9. Effects of trichloroethylene and perchloroethylene on wild rodents at Edwards Air Force Base, California, USA.

    PubMed

    Spring, Sarah E; Miles, A Keith; Anderson, Michael J

    2004-09-01

    Effects of inhalation of volatilized trichloroethylene (TCE) or perchloroethylene (PCE) were assessed based on the health and population size of wild, burrowing mammals at Edwards Air Force Base (CA, USA). Organic soil-vapor concentrations were measured at three sites with aquifer contamination of TCE or PCE of 5.5 to 77 mg/L and at two uncontaminated reference sites. Population estimates of kangaroo rats (Dipodomys merriami and D. panamintinus) as well as hematology, blood chemistry, and histopathology of kangaroo rats and deer mice (Peromyscus maniculatus) were compared between contaminated and uncontaminated populations. Maximum soil-gas concentrations associated with groundwater contamination were less than 1.5 microl/L of TCE and 0.07 microl/L of PCE. Population estimates of kangaroo rats were similar at contaminated and reference sites. Hematology, blood chemistry, and histopathology of kangaroo rats and deer mice indicated no evidence of health effects caused by exposure. Trichloroethylene or PCE in groundwater and in related soil gas did not appear to reduce the size of small mammal populations or impair the health of individuals. PMID:15378993

  10. High-precision horizontally directed force measurements for high dead loads based on a differential electromagnetic force compensation system

    NASA Astrophysics Data System (ADS)

    Vasilyan, Suren; Rivero, Michel; Schleichert, Jan; Halbedel, Bernd; Fröhlich, Thomas

    2016-04-01

    In this paper, we present an application for realizing high-precision horizontally directed force measurements in the order of several tens of nN in combination with high dead loads of about 10 N. The set-up is developed on the basis of two identical state-of-the-art electromagnetic force compensation (EMFC) high precision balances. The measurement resolution of horizontally directed single-axis quasi-dynamic forces is 20 nN over the working range of  ±100 μN. The set-up operates in two different measurement modes: in the open-loop mode the mechanical deflection of the proportional lever is an indication of the acting force, whereas in the closed-loop mode it is the applied electric current to the coil inside the EMFC balance that compensates deflection of the lever to the offset zero position. The estimated loading frequency (cutoff frequency) of the set-up in the open-loop mode is about 0.18 Hz, in the closed-loop mode it is 0.7 Hz. One of the practical applications that the set-up is suitable for is the flow rate measurements of low electrically conducting electrolytes by applying the contactless technique of Lorentz force velocimetry. Based on a previously developed set-up which uses a single EMFC balance, experimental, theoretical and numerical analyses of the thermo-mechanical properties of the supporting structure are presented.

  11. Evidence for insolation and Pacific forcing of late glacial through Holocene climate in the Central Mojave Desert (Silver Lake, CA)

    NASA Astrophysics Data System (ADS)

    Kirby, Matthew E.; Knell, Edward J.; Anderson, William T.; Lachniet, Matthew S.; Palermo, Jennifer; Eeg, Holly; Lucero, Ricardo; Murrieta, Rosa; Arevalo, Andrea; Silveira, Emily; Hiner, Christine A.

    2015-09-01

    Silver Lake is the modern terminal playa of the Mojave River in southern California (USA). As a result, it is well located to record both influences from the winter precipitation dominated San Bernardino Mountains - the source of the Mojave River - and from the late summer to early fall North American monsoon at Silver Lake. Here, we present various physical, chemical and biological data from a new radiocarbon-dated, 8.2 m sediment core taken from Silver Lake that spans modern through 14.8 cal ka BP. Texturally, the core varies between sandy clay, clayey sand, and sand-silt-clay, often with abrupt sedimentological transitions. These grain-size changes are used to divide the core into six lake status intervals over the past 14.8 cal ka BP. Notable intervals include a dry Younger Dryas chronozone, a wet early Holocene terminating 7.8 - 7.4 cal ka BP, a distinct mid-Holocene arid interval, and a late Holocene return to ephemeral lake conditions. A comparison to potential climatic forcings implicates a combination of changing summer - winter insolation and tropical and N Pacific sea-surface temperature dynamics as the primary drivers of Holocene climate in the central Mojave Desert.

  12. 75 FR 30689 - Modification of Class C Airspace; Beale Air Force Base, CA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-02

    ... Department of Transportation (DOT) Regulatory Policies and Procedures (44 FR 11034; February 26, 1979); and..., 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The incorporation by... Federal Aviation Administration 14 CFR Part 71 RIN 2120-AA66 Modification of Class C Airspace; Beale...

  13. CONTROL BUILDING, WEST FRONT SHOWING ENTRANCE Edwards Air Force ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CONTROL BUILDING, WEST FRONT SHOWING ENTRANCE - Edwards Air Force Base, X-15 Engine Test Complex, Firing Control Building, Rogers Dry Lake, east of runway between North Base & South Base, Boron, Kern County, CA

  14. Optimal tracking of a sEMG based force model for a prosthetic hand.

    PubMed

    Potluri, Chandrasekhar; Anugolu, Madhavi; Yihun, Yimesker; Jensen, Alex; Chiu, Steve; Schoen, Marco P; Naidu, D Subbaram

    2011-01-01

    This paper presents a surface electromyographic (sEMG)-based, optimal control strategy for a prosthetic hand. System Identification (SI) is used to obtain the dynamic relation between the sEMG and the corresponding skeletal muscle force. The input sEMG signal is preprocessed using a Half-Gaussian filter and fed to a fusion-based Multiple Input Single Output (MISO) skeletal muscle force model. This MISO system model provides the estimated finger forces to be produced as input to the prosthetic hand. Optimal tracking method has been applied to track the estimated force profile of the Fusion based sEMG-force model. The simulation results show good agreement between reference force profile and the actual force. PMID:22254629

  15. Bimanual elbow exoskeleton: Force based protocol and rehabilitation quantification.

    PubMed

    Alavi, N; Herrnstadt, G; Randhawa, B K; Boyd, L A; Menon, C

    2015-08-01

    An aging population, along with the increase in cardiovascular disease incidence that accompanies this demographic shift, is likely to increase both the economic and medical burden associated with stroke in western societies. Rehabilitation, the standard treatment for stroke, can be expanded and augmented with state of the art technologies, such as robotic therapy. This paper expands upon a recent work involving a force-feedback master-slave bimanual exoskeleton for elbow rehabilitation, named a Bimanual Wearable Robotic Device (BWRD). Elbow force data acquired during the execution of custom tasks is analyzed to demonstrate the feasibility of tracking patient progress. Two training tasks that focus on applied forces are examined. The first is called "slave arm follow", which uses the absolute angular impulse as a metric; the second is called "conditional arm static", which uses the rise time to target as a metric, both presented here. The outcomes of these metrics are observed over three days. PMID:26737329

  16. SO2 retention by reactivated CaO-based sorbent from multiple CO2 capture cycles.

    PubMed

    Manovic, Vasilije; Anthony, Edward J

    2007-06-15

    This paper examines the reactivation of spent sorbent, produced from multiple CO2 capture cycles, for use in SO2 capture. CaO-based sorbent samples were obtained from Kelly Rock limestone using three particle size ranges, each containing different impurities levels. Using a thermogravimetric analyzer (TGA), the sulfation behavior of partially sulfated and unsulfated samples obtained after multiple calcination-carbonation cycles in a tube furnace (TF), following steam reactivation in a pressurized reactor, is examined. In addition, samples calcined/sintered under different conditions after hydration are also examined. The results show that suitably treated spent sorbent has better sulfation characteristics than that of the original sorbent. Thus for example, after 2 h sulfation, > 80% of the CaO was sulfated. In addition, the sorbent showed significant activity even after 4 h when > 95% CaO was sulfated. The results were confirmed by X-ray diffraction (XRD) analysis, which showed that, by the end of the sulfation process, samples contained CaSO4 with only traces of unreacted CaO. The superior behavior of spent reactivated sorbent appears to be due to swelling of the sorbent particles during steam hydration. This enables the development of a more suitable pore surface area and pore volume distribution for sulfation, and this has been confirmed by N2 adsorption-desorption isotherms and the Barrett-Joyner-Halenda (BJH) method. The surface area morphology of sorbent after reactivation was examined by scanning electron microscopy (SEM). Ca(OH)2 crystals were seen, which displayed their regular shape, and their elemental composition was confirmed by energy-dispersive X-ray (EDX) analysis. The improved characteristics of spent reactivated sorbent in comparison to the original and to the sorbent calcined under different conditions and hydrated indicate the beneficial effect of CO2 cycles on sorbent reactivation and subsequent sulfation. These results allow us to propose a

  17. Credit USAF, ca. 1943. Original housed in the Muroc Flight ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Credit USAF, ca. 1943. Original housed in the Muroc Flight Test Base, Unit History, 1 September 1942 - 30 June 1945. Alfred F. Simpson Historical Research Agency. United States Air Force. Maxwell AFB, Alabama. Historic view looking north across southwest end of swimming pool as army personnel work on finishing the pool bottom. View looks towards Mess Hall (T-10) on Second Street - Edwards Air Force Base, North Base, Swimming Pool, Second Street, Boron, Kern County, CA

  18. 4. Credit USAF, ca. 1945. Original housed in the Muroc ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. Credit USAF, ca. 1945. Original housed in the Muroc Flight Test Base, Unit History, 1 September 1942 - 30 June 1945. Alfred F. Simpson Historical Research Agency. United States Air Force. Maxwell AFB, Alabama. Photographic copy of photograph captioned "Hangar No. 2 Hydraulics Room." Location within Building 4402 not determined. - Edwards Air Force Base, North Base, Hangar No. 2, First & A Streets, Boron, Kern County, CA

  19. Study on Optimized Elman Neural Network Classification Algorithm Based on PLS and CA

    PubMed Central

    Zhao, Dean; Shen, Tian; Zhao, Yuyan

    2014-01-01

    High-dimensional large sample data sets, between feature variables and between samples, may cause some correlative or repetitive factors, occupy lots of storage space, and consume much computing time. Using the Elman neural network to deal with them, too many inputs will influence the operating efficiency and recognition accuracy; too many simultaneous training samples, as well as being not able to get precise neural network model, also restrict the recognition accuracy. Aiming at these series of problems, we introduce the partial least squares (PLS) and cluster analysis (CA) into Elman neural network algorithm, by the PLS for dimension reduction which can eliminate the correlative and repetitive factors of the features. Using CA eliminates the correlative and repetitive factors of the sample. If some subclass becomes small sample, with high-dimensional feature and fewer numbers, PLS shows a unique advantage. Each subclass is regarded as one training sample to train the different precise neural network models. Then simulation samples are discriminated and classified into different subclasses, using the corresponding neural network to recognize it. An optimized Elman neural network classification algorithm based on PLS and CA (PLS-CA-Elman algorithm) is established. The new algorithm aims at improving the operating efficiency and recognition accuracy. By the case analysis, the new algorithm has unique superiority, worthy of further promotion. PMID:25165470

  20. Chelate titrations of Ca(2+) and Mg(2+) using microfluidic paper-based analytical devices.

    PubMed

    Karita, Shingo; Kaneta, Takashi

    2016-06-14

    We developed microfluidic paper-based analytical devices (μPADs) for the chelate titrations of Ca(2+) and Mg(2+) in natural water. The μPAD consisted of ten reaction zones and ten detection zones connected through narrow channels to a sample zone located at the center. Buffer solutions with a pH of 10 or 13 were applied to all surfaces of the channels and zones. Different amounts of ethylenediaminetetraacetic acid (EDTA) were added to the reaction zones and a consistent amount of a metal indicator (Eriochrome Black T or Calcon) was added to the detection zones. The total concentrations of Ca(2+) and Mg(2+) (total hardness) in the water were measured using a μPAD containing a buffer solution with a pH of 10, whereas only Ca(2+) was titrated using a μPAD prepared with a potassium hydroxide solution with a pH of 13. The μPADs permitted the determination of Ca(2+) and Mg(2+) in mineral water, river water, and seawater samples within only a few minutes using only the naked eye-no need of instruments. PMID:27181645

  1. Improve photovoltaic performance of titanium dioxide nanorods based dye-sensitized solar cells by Ca-doping

    SciTech Connect

    Li, Weixin; Yang, Junyou Zhang, Jiaqi; Gao, Sheng; Luo, Yubo; Liu, Ming

    2014-09-15

    Highlights: • TiO{sub 2} nanorods doped with Ca ions were synthesized by one-step hydrothermal method. • The flat band edge of rutile TiO{sub 2} shifted positively via Ca-doping. • The photoelectric conversion efficiency of dye-sensitized solar cells (DSSCs) based on TiO{sub 2} electrode was much enhanced by Ca-doping. • A relatively high open circuit voltage was obtained by adopting Ca-doped TiO{sub 2} nanorods electrode. - Abstract: Ca-doped TiO{sub 2} nanorod arrays were prepared via the one-step hydrothermal method successfully, and the effect of Ca ions content on the photovoltaic conversion efficiency of dye-sensitized solar cells has been fully discussed in the paper. Although no obvious change on the microstructure and morphology was observed by field emission scanning electron microscope and transmission electron microscope for the Ca-doped samples, the results of X-ray diffraction and X-ray photoelectron spectroscopy confirmed that Ti{sup 4+} was substituted with Ca{sup 2+} successfully. UV–vis spectroscopy results revealed that the flat band edge shifted positively by Ca ions doping. The photovoltaic conversion efficiency of the dye-sensitized solar cells based on the 2 mol% Ca-doped TiO{sub 2} electrode was 43% higher than that of the undoped one due to the less recombination possibility.

  2. Problem decomposition by mutual information and force-based clustering

    NASA Astrophysics Data System (ADS)

    Otero, Richard Edward

    The scale of engineering problems has sharply increased over the last twenty years. Larger coupled systems, increasing complexity, and limited resources create a need for methods that automatically decompose problems into manageable sub-problems by discovering and leveraging problem structure. The ability to learn the coupling (inter-dependence) structure and reorganize the original problem could lead to large reductions in the time to analyze complex problems. Such decomposition methods could also provide engineering insight on the fundamental physics driving problem solution. This work forwards the current state of the art in engineering decomposition through the application of techniques originally developed within computer science and information theory. The work describes the current state of automatic problem decomposition in engineering and utilizes several promising ideas to advance the state of the practice. Mutual information is a novel metric for data dependence and works on both continuous and discrete data. Mutual information can measure both the linear and non-linear dependence between variables without the limitations of linear dependence measured through covariance. Mutual information is also able to handle data that does not have derivative information, unlike other metrics that require it. The value of mutual information to engineering design work is demonstrated on a planetary entry problem. This study utilizes a novel tool developed in this work for planetary entry system synthesis. A graphical method, force-based clustering, is used to discover related sub-graph structure as a function of problem structure and links ranked by their mutual information. This method does not require the stochastic use of neural networks and could be used with any link ranking method currently utilized in the field. Application of this method is demonstrated on a large, coupled low-thrust trajectory problem. Mutual information also serves as the basis for an

  3. Rasch model based analysis of the Force Concept Inventory

    NASA Astrophysics Data System (ADS)

    Planinic, Maja; Ivanjek, Lana; Susac, Ana

    2010-06-01

    The Force Concept Inventory (FCI) is an important diagnostic instrument which is widely used in the field of physics education research. It is therefore very important to evaluate and monitor its functioning using different tools for statistical analysis. One of such tools is the stochastic Rasch model, which enables construction of linear measures for persons and items from raw test scores and which can provide important insight in the structure and functioning of the test (how item difficulties are distributed within the test, how well the items fit the model, and how well the items work together to define the underlying construct). The data for the Rasch analysis come from the large-scale research conducted in 2006-07, which investigated Croatian high school students’ conceptual understanding of mechanics on a representative sample of 1676 students (age 17-18 years). The instrument used in research was the FCI. The average FCI score for the whole sample was found to be (27.7±0.4)% , indicating that most of the students were still non-Newtonians at the end of high school, despite the fact that physics is a compulsory subject in Croatian schools. The large set of obtained data was analyzed with the Rasch measurement computer software WINSTEPS 3.66. Since the FCI is routinely used as pretest and post-test on two very different types of population (non-Newtonian and predominantly Newtonian), an additional predominantly Newtonian sample ( N=141 , average FCI score of 64.5%) of first year students enrolled in introductory physics course at University of Zagreb was also analyzed. The Rasch model based analysis suggests that the FCI has succeeded in defining a sufficiently unidimensional construct for each population. The analysis of fit of data to the model found no grossly misfitting items which would degrade measurement. Some items with larger misfit and items with significantly different difficulties in the two samples of students do require further examination

  4. Vandenberg Air Force Base Upper Level Wind Launch Weather Constraints

    NASA Technical Reports Server (NTRS)

    Shafer, Jaclyn A.; Wheeler, Mark M.

    2012-01-01

    The 30th Operational Support Squadron Weather Flight (30 OSSWF) provides comprehensive weather services to the space program at Vandenberg Air Force Base (VAFB) in California. One of their responsibilities is to monitor upper-level winds to ensure safe launch operations of the Minuteman III ballistic missile. The 30 OSSWF tasked the Applied Meteorology Unit (AMU) to analyze VAFB sounding data with the goal of determining the probability of violating (PoV) their upper-level thresholds for wind speed and shear constraints specific to this launch vehicle, and to develop a tool that will calculate the PoV of each constraint on the day of launch. In order to calculate the probability of exceeding each constraint, the AMU collected and analyzed historical data from VAFB. The historical sounding data were retrieved from the National Oceanic and Atmospheric Administration Earth System Research Laboratory archive for the years 1994-2011 and then stratified into four sub-seasons: January-March, April-June, July-September, and October-December. The maximum wind speed and 1000-ft shear values for each sounding in each subseason were determined. To accurately calculate the PoV, the AMU determined the theoretical distributions that best fit the maximum wind speed and maximum shear datasets. Ultimately it was discovered that the maximum wind speeds follow a Gaussian distribution while the maximum shear values follow a lognormal distribution. These results were applied when calculating the averages and standard deviations needed for the historical and real-time PoV calculations. In addition to the requirements outlined in the original task plan, the AMU also included forecast sounding data from the Rapid Refresh model. This information provides further insight for the launch weather officers (LWOs) when determining if a wind constraint violation will occur over the next few hours on day of launch. The interactive graphical user interface (GUI) for this project was developed in

  5. Rasch Model Based Analysis of the Force Concept Inventory

    ERIC Educational Resources Information Center

    Planinic, Maja; Ivanjek, Lana; Susac, Ana

    2010-01-01

    The Force Concept Inventory (FCI) is an important diagnostic instrument which is widely used in the field of physics education research. It is therefore very important to evaluate and monitor its functioning using different tools for statistical analysis. One of such tools is the stochastic Rasch model, which enables construction of linear…

  6. Lorentz force velocimetry based on time-of-flight measurements

    NASA Astrophysics Data System (ADS)

    Viré, Axelle; Knaepen, Bernard; Thess, André

    2010-12-01

    Lorentz force velocimetry (LFV) is a contactless technique for the measurement of liquid metal flowrates. It consists of measuring the force acting upon a magnetic system and arising from the interaction between an external magnetic field and the flow of an electrically conducting fluid. In this study, a new design is proposed so as to make the measurement independent of the fluid's electrical conductivity. It is made of one or two coils placed around a circular pipe. The forces produced on each coil are recorded in time as the liquid metal flows through the pipe. It is highlighted that the auto- or cross-correlation of these forces can be used to determine the flowrate. The reliability of the flowmeter is first investigated with a synthetic velocity profile associated with a single vortex ring, which is convected at a constant speed. This configuration is similar to the movement of a solid rod and enables a simple analysis of the flowmeter. Then, the flowmeter is applied to a realistic three-dimensional turbulent flow. In both cases, the influence of the coil radii, coil separation, and sign of the coil-carrying currents is systematically assessed. The study is entirely numerical and uses a second-order finite volume method. Two sets of simulations are performed. First, the equations of motion are solved without accounting for the effect of the magnetic field on the flow (kinematic simulations). Second, the Lorentz force is explicitly added to the momentum balance (dynamic simulations), and the influence of the external magnetic field on the flow is then quantified.

  7. Endosome-based protein trafficking and Ca2+ homeostasis in the heart

    PubMed Central

    Curran, Jerry; Makara, Michael A.; Mohler, Peter J.

    2015-01-01

    The ability to dynamically regulate, traffic, retain, and recycle proteins within the cell membrane is fundamental to life and central to the normal function of the heart. In the cardiomyocyte, these pathways are essential for the regulation of Ca2+, both at the level of the plasma membrane, but also in local cellular domains. One intracellular pathway often overlooked in relation to cardiovascular Ca2+ regulation and signaling is the endosome-based trafficking pathway. Highlighting its importance, this system and its molecular components are evolutionarily conserved across all metazoans. However, remarkably little is known of how endosome-based protein trafficking and recycling functions within mammalian cells systems, especially in the heart. As the endosomal system acts to regulate the expression and localization of membrane proteins central for cardiac Ca2+ regulation, understanding the in vivo function of this system in the heart is critical. This review will focus on endosome-based protein trafficking in the heart in both health and disease with special emphasis for the role of endocytic regulatory proteins, C-terminal Eps15 homology domain-containing proteins (EHDs). PMID:25709583

  8. Forces Applied at the Skull Base during Transnasal Endoscopic Transsphenoidal Pituitary Tumor Excision

    PubMed Central

    Bekeny, James R.; Swaney, Philip J.; Webster, Robert J.; Russell, Paul T.; Weaver, Kyle D.

    2013-01-01

    Objectives Our laboratory is developing a surgical robotic system to further improve dexterity and visualization that will allow for broader application of transnasal skull base surgery. To optimize this system, intraoperative force data are required. Using a modified curette, force data were recorded and analyzed during pituitary tumor excision. Design A neurosurgical curette was modified by the addition of a force sensor. The instrument was validated in an in vitro model to measure forces during simulated pituitary tumor excision. Following this, intraoperative force data from three patients during transnasal endoscopic excision of pituitary tumors was obtained. Setting Academic medical center. Main Outcome Measures Forces applied at the skull base during surgical excision of pituitary tumors. Results Average forces applied during in vitro testing ranged from 0.1 to 0.15 N. Average forces recorded during in vivo testing ranged from 0.1 to 0.5 N. Maximal forces occurred with collisions of the bony sella. The average maximal force was 1.61 N. There were no complications related to the use of the modified curette. Conclusions Forces to remove pituitary tumor are small and are similar between patients. The in vitro model presented here is adequate for further testing of a robotic skull base surgery system. PMID:24436934

  9. Monitoring biological impacts of space shuttle launches from Vandenberg Air Force Base: Establishment of baseline conditions

    NASA Technical Reports Server (NTRS)

    Schmaizer, Paul A.; Hinkle, C. Ross

    1987-01-01

    Space shuttle launches produce environmental impacts resulting from the formation of an exhaust cloud containing hydrogen chloride aerosols and aluminum oxide particulates. Studies have shown that most impacts occur near-field (within 1.5 km) of the launch site while deposition from launches occurs far-field (as distant as 22 km). In order to establish baseline conditions of vegetation and soils in the areas likely to be impacted by shuttle launches from Vandenberg Air Force Base (VAFB), vegetation and soils in the vicinity of Space Launch Complex-6 (SLC-6) were sampled and a vegetation map prepared. The areas likely to be impacted by launches were determined considering the structure of the launch complex, the prevailing winds, the terrain, and predictions of the Rocket Exhaust Effluent Diffusion Model (REEDM). Fifty vegetation transects were established and sampled in March 1986 and resampled in September 1986. A vegetation map was prepared for six Master Planning maps surrounding SLC-6 using LANDSAT Thematic Mapper imagery as well as color and color infrared aerial photography. Soil samples were collected form the 0 to 7.5 cm layer at all transects in the wet season and at a subsample of the transects in the dry season and analyzed for pH, organic matter, conductivity, cation exchange capacity, exchangeable Ca, Mg, Na, K, and Al, available NH3-N, PO4-P, Cu, Fe, Mn, Zn, and TKN.

  10. Credit USAF, ca. 1945. Original housed in the Muroc Flight ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Credit USAF, ca. 1945. Original housed in the Muroc Flight Test Base, Unit History, 1 September 1942 - 30 June 1945. Alfred F. Simpson Historical Research Agency. United States Air Force. Maxwell AFB, Alabama. View looks north at a hutment typical of several structures erected at the Muroc Flight Test Base (North Base) ca. 1943-1945. Similar structures, Buildings T-61, T-62 and T-63, lie in the distance behind T-40 - Edwards Air Force Base, North Base, Barracks T-40, Second & A Streets, Boron, Kern County, CA

  11. Credit USAF, ca. 1943. Original housed in the Photograph Files, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Credit USAF, ca. 1943. Original housed in the Photograph Files, AFFTC/HO, Edwards AFB, California. Historic view of finished swimming pool, with fence and lifeguard station. View looks west - Edwards Air Force Base, North Base, Swimming Pool, Second Street, Boron, Kern County, CA

  12. Rigorous force field optimization principles based on statistical distance minimization

    SciTech Connect

    Vlcek, Lukas; Chialvo, Ariel A.

    2015-10-14

    We use the concept of statistical distance to define a measure of distinguishability between a pair of statistical mechanical systems, i.e., a model and its target, and show that its minimization leads to general convergence of the model’s static measurable properties to those of the target. We exploit this feature to define a rigorous basis for the development of accurate and robust effective molecular force fields that are inherently compatible with coarse-grained experimental data. The new model optimization principles and their efficient implementation are illustrated through selected examples, whose outcome demonstrates the higher robustness and predictive accuracy of the approach compared to other currently used methods, such as force matching and relative entropy minimization. We also discuss relations between the newly developed principles and established thermodynamic concepts, which include the Gibbs-Bogoliubov inequality and the thermodynamic length.

  13. Low-temperature linear thermal rectifiers based on Coriolis forces

    NASA Astrophysics Data System (ADS)

    Suwunnarat, Suwun; Li, Huanan; Fleischmann, Ragnar; Kottos, Tsampikos

    2016-04-01

    We demonstrate that a three-terminal harmonic symmetric chain in the presence of a Coriolis force, produced by a rotating platform that is used to place the chain, can produce thermal rectification. The direction of heat flow is reconfigurable and controlled by the angular velocity Ω of the rotating platform. A simple three-terminal triangular lattice is used to demonstrate the proposed principle.

  14. 33 CFR 334.744 - Eglin Poquito Housing at Eglin Air Force Base, Fla.; restricted area.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Air Force Base, Fla.; restricted area. 334.744 Section 334.744 Navigation and Navigable Waters CORPS... REGULATIONS § 334.744 Eglin Poquito Housing at Eglin Air Force Base, Fla.; restricted area. (a) The area. The restricted area shall encompass all navigable waters of the United States, as defined at 33 CFR part...

  15. 33 CFR 334.740 - North Shore Choctawhatchee Bay, Eglin Air Force Base, Fla.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Shore Choctawhatchee Bay, Eglin Air Force Base, Fla. (a) The area. The restricted area shall encompass all navigable waters of the United States as defined at 33 CFR part 329 within the area bounded by a..., Eglin Air Force Base, Fla. 334.740 Section 334.740 Navigation and Navigable Waters CORPS OF...

  16. 33 CFR 334.740 - North Shore Choctawhatchee Bay, Eglin Air Force Base, Fla.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Shore Choctawhatchee Bay, Eglin Air Force Base, Fla. (a) The area. The restricted area shall encompass all navigable waters of the United States as defined at 33 CFR part 329 within the area bounded by a..., Eglin Air Force Base, Fla. 334.740 Section 334.740 Navigation and Navigable Waters CORPS OF...

  17. 33 CFR 334.740 - North Shore Choctawhatchee Bay, Eglin Air Force Base, Fla.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Shore Choctawhatchee Bay, Eglin Air Force Base, Fla. (a) The area. The restricted area shall encompass all navigable waters of the United States as defined at 33 CFR part 329 within the area bounded by a..., Eglin Air Force Base, Fla. 334.740 Section 334.740 Navigation and Navigable Waters CORPS OF...

  18. The salt marsh vegetation spread dynamics simulation and prediction based on conditions optimized CA

    NASA Astrophysics Data System (ADS)

    Guan, Yujuan; Zhang, Liquan

    2006-10-01

    The biodiversity conservation and management of the salt marsh vegetation relies on processing their spatial information. Nowadays, more attentions are focused on their classification surveying and describing qualitatively dynamics based on RS images interpreted, rather than on simulating and predicting their dynamics quantitatively, which is of greater importance for managing and planning the salt marsh vegetation. In this paper, our notion is to make a dynamic model on large-scale and to provide a virtual laboratory in which researchers can run it according requirements. Firstly, the characteristic of the cellular automata was analyzed and a conclusion indicated that it was necessary for a CA model to be extended geographically under varying conditions of space-time circumstance in order to make results matched the facts accurately. Based on the conventional cellular automata model, the author introduced several new conditions to optimize it for simulating the vegetation objectively, such as elevation, growth speed, invading ability, variation and inheriting and so on. Hence the CA cells and remote sensing image pixels, cell neighbors and pixel neighbors, cell rules and nature of the plants were unified respectively. Taking JiuDuanSha as the test site, where holds mainly Phragmites australis (P.australis) community, Scirpus mariqueter (S.mariqueter) community and Spartina alterniflora (S.alterniflora) community. The paper explored the process of making simulation and predictions about these salt marsh vegetable changing with the conditions optimized CA (COCA) model, and examined the links among data, statistical models, and ecological predictions. This study exploited the potential of applying Conditioned Optimized CA model technique to solve this problem.

  19. A Thermodynamic Model for Predicting Phosphorus Partition between CaO-based Slags and Hot Metal during Hot Metal Dephosphorization Pretreatment Process Based on the Ion and Molecule Coexistence Theory

    NASA Astrophysics Data System (ADS)

    Yang, Xue-min; Li, Jin-yan; Chai, Guo-ming; Duan, Dong-ping; Zhang, Jian

    2016-08-01

    dephosphorization ability of the CaO-based slags. Furthermore, a parabolic relationship of L P against binary basicity or complex basicity CB2 and CB3 can be established at binary basicity in 1.8 or at complex basicity CB2 and CB3 in 2.0 corresponding to the maximum of dephosphorization ability of the CaO-based slags. However, the linear relationship between L P and optical basicity can only be correlated with the mathematically regressed Λ_{{FeO}} = 1.0 and Λ_{{{{Fe}}_{ 2} {{O}}_{ 3}}} =0.75. A great gradient of oxygen potential or oxygen activity a %,O between the dynamically formed metal film beneath slag-metal interface and hot metal bath is the main driving forces of hot metal dephosphorization by the CaO-based slags. The formed metal film with high oxygen content and low carbon content can dynamically be exchanged or replaced by hot metal elements from bath during hot metal dephosphorization process until dephosphorization products mainly as 3CaO·P2O5 are saturated in the CaO-based slags.

  20. SR-71 Tail #844 Landing at Edwards Air Force Base

    NASA Technical Reports Server (NTRS)

    1996-01-01

    With distinctive heat waves trailing behind its engines, NASA Dryden Flight Research Center's SR-71A, tail number 844, lands at the Edwards AFB runway after a 1996 flight. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the airstream. One of Dryden's SR-71s was used for the Linear Aerospike Rocket Engine, or LASRE Experiment. Another earlier project consisted of a series of flights using the SR-71 as a science camera platform for NASA's Jet Propulsion Laboratory in Pasadena, California. An upward

  1. Noncontact scanning force microscopy based on a modified tuning fork sensor

    NASA Astrophysics Data System (ADS)

    Göttlich, Hagen; Stark, Robert W.; Pedarnig, Johannes D.; Heckl, Wolfgang M.

    2000-08-01

    Distance control using a tuning fork setup for the detection of shear forces is a standard configuration in scanning near-field optical microscopy (SNOM). Based on this concept, a modified sensor was developed, where a standard silicon tip for atomic force microscopy (AFM) is attached to the front end of one prong of a 100 kHz quartz tuning fork oscillator. Comparison of force curves of a standard tapping-mode AFM cantilever, a conventional fiber tip SNOM sensor and the novel AFM tip shear force sensor demonstrate an enhanced stability and sensitivity of the new sensor. Due to the rigid sensor design the force curves of the AFM tip shear force sensor indicate a perfect noncontact behavior under normal conditions in air. Noncontact images show a comparable resolution to conventional force microscopy.

  2. Debonding forces of three different customized bases of a lingual bracket system

    PubMed Central

    Sung, Jang-Won; Kwon, Tae-Yub

    2013-01-01

    Objective The purpose of this study was to investigate whether extension of the custom base is necessary for enhancement of bond strength, by comparing the debonding forces and residual adhesives of 3 different lingual bracket systems. Methods A total of 42 extracted upper premolars were randomly divided into 3 groups of 14 each for bonding with brackets having (1) a conventional limited resin custom base; (2) an extended gold alloy custom base: Incognito™; and (3) an extended resin custom base: KommonBase™. The bonding area was measured by scanning the bracket bases with a 3-dimensional digital scanner. The debonding force was measured with an Instron universal testing machine, which applied an occlusogingival shear force. Results The mean debonding forces were 60.83 N (standard deviation [SD] 10.12), 69.29 N (SD 9.59), and 104.35 N (SD17.84) for the limited resin custom base, extended gold alloy custom base, and extended resin custom base, respectively. The debonding force observed with the extended resin custom base was significantly different from that observed with the other bases. In addition, the adhesive remnant index was significantly higher with the extended gold alloy custom base. Conclusions All 3 custom-base lingual brackets can withstand occlusal and orthodontic forces. We conclude that effective bonding of lingual brackets can be obtained without extension of the custom base. PMID:24228238

  3. Tapping mode quartz crystal resonator based scanning force microscopy

    NASA Astrophysics Data System (ADS)

    Seo, Yongho; Jhe, Wonho

    2005-01-01

    We have built a high-speed, tapping mode scanning force microscope using a high frequency quartz crystal resonator. In our design, a cantilever tip was attached to the end of an optical fiber which was glued to a thickness shear mode, AT-cut quartz crystal resonator so as to vibrate in the longitudinal direction. This design allows the microscope to be operated in tapping mode with the flexibility of shear mode operation, which leads to an expected improvement of image quality. Furthermore, combining this geometry with an optical microscope leads to the possibility of commercial applications.

  4. Microfluidic sorting system based on optical force switching

    NASA Astrophysics Data System (ADS)

    Hoi, S.-K.; Udalagama, C.; Sow, C.-H.; Watt, F.; Bettiol, A. A.

    2009-12-01

    We report a versatile, and automatic method for sorting cells and particles in a three dimensional polydimethylsiloxane (PDMS) structure consisting of two cross-microchannels. As microspheres or yeast cells are fed continuously into a lower channel, a line shaped focused laser beam is applied (perpendicular to the direction of flow) at the crossing junction of the two channels. The scattering force of the laser beam was employed to push microparticles matching specific criteria upwards from one channel to another. The force depends on the intrinsic properties of the particles such as their refractive index and size, as well as the laser power and the fluid flow speed. The combination of these parameters gives a tunable selection criterion for the effective and efficient sorting of the particles. The introduction of the cylindrical lens into the optical train allows for simultaneous manipulation of multiple particles which has significantly increased the efficiency and throughput of the sorting. A high aspect ratio microchannel (A.R.=1.6) was found to enhance the sorting performance of the device. By careful control of the microparticle flow rate, near 100% sorting efficiency was achieved.

  5. 5. NORTH SIDE AND WEST REAR. Edwards Air Force ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. NORTH SIDE AND WEST REAR. - Edwards Air Force Base, South Base Sled Track, Firing & Control Blockhouse for 10,000-foot Track, South of Sled Track at midpoint of 20,000-foot track, Lancaster, Los Angeles County, CA

  6. 6. OUTER BLAST DOOR, WEST REAR. Edwards Air Force ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. OUTER BLAST DOOR, WEST REAR. - Edwards Air Force Base, South Base Sled Track, Firing & Control Blockhouse for 10,000-foot Track, South of Sled Track at midpoint of 20,000-foot track, Lancaster, Los Angeles County, CA

  7. Structuralization of Ca(2+)-Based Metal-Organic Frameworks Prepared via Coordination Replication of Calcium Carbonate.

    PubMed

    Sumida, Kenji; Hu, Ming; Furukawa, Shuhei; Kitagawa, Susumu

    2016-04-01

    The emergence of metal-organic frameworks (MOFs) as potential candidates to supplant existing adsorbent types in real-world applications has led to an explosive growth in the number of compounds available to researchers, as well as in the diversity of the metal salts and organic linkers from which they are derived. In this context, the use of carbonate-based precursors as metal sources is of interest due to their abundance in mineral deposits and their reaction chemistry with acids, resulting in just water and carbon dioxide as side products. Here, we have explored the use of calcium carbonate as a metal source and demonstrate its versatility as a precursor to several known frameworks, as well as a new flexible compound based on the 2,5-dihydroxybenzoquinone (H2dhbq) linker, Ca(dhbq)(H2O)2. Furthermore, inspired by the ubiquity and unique structures of biomineralized forms of calcium carbonate, we also present examples of the preparation of superstructures of Ca-based MOFs via the coordination replication technique. In all, the results confirm the suitability of carbonate-based metal sources for the preparation of MOFs and further expand upon the growing scope of coordination replication as a convenient strategy for the preparation of structuralized materials. PMID:27002690

  8. Base-resolution profiling of active DNA demethylation using MAB-seq and caMAB-seq.

    PubMed

    Wu, Hao; Wu, Xiaoji; Zhang, Yi

    2016-06-01

    A complete understanding of the function of the ten-eleven translocation (TET) family of dioxygenase-mediated DNA demethylation requires new methods to quantitatively map oxidized 5-methylcytosine (5mC) bases at high resolution. We have recently developed a methylase-assisted bisulfite sequencing (MAB-seq) method that allows base-resolution mapping of 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC), two oxidized 5mC bases indicative of active DNA demethylation events. In standard bisulfite sequencing (BS-seq), unmodified C, 5fC and 5caC are read as thymine; thus 5fC and 5caC cannot be distinguished from C. In MAB-seq, unmodified C is enzymatically converted to 5mC, allowing direct mapping of rare modifications such as 5fC and 5caC. By combining MAB-seq with chemical reduction of 5fC to 5hmC, we also developed caMAB-seq, a method for direct 5caC mapping. Compared with subtraction-based mapping methods, MAB-seq and caMAB-seq require less sequencing effort and enable robust statistical calling of 5fC and/or 5caC. MAB-seq and caMAB-seq can be adapted to map 5fC/5caC at the whole-genome scale (WG-MAB-seq), within specific genomic regions enriched for enhancer-marking histone modifications (chromatin immunoprecipitation (ChIP)-MAB-seq), or at CpG-rich sequences (reduced-representation (RR)-MAB-seq) such as gene promoters. The full protocol, including DNA preparation, enzymatic treatment, library preparation and sequencing, can be completed within 6-8 d. PMID:27172168

  9. Regulation of muscle force in the absence of actin-myosin-based cross-bridge interaction.

    PubMed

    Leonard, T R; Herzog, W

    2010-07-01

    For the past half century, the sliding filament-based cross-bridge theory has been the cornerstone of our understanding of how muscles contract. According to this theory, active force can only occur if there is overlap between the contractile filaments, actin and myosin. Otherwise, forces are thought to be caused by passive structural elements and are assumed to vary solely because of the length of the muscle. We observed increases in muscle force by a factor of 3 to 4 above the purely passive forces for activated and stretched myofibrils in the absence of actin-myosin overlap. We show that this dramatic increase in force is crucially dependent on the presence of the structural protein titin, cannot be explained with calcium activation, and is regulated by actin-myosin-based cross-bridge forces before stretching. We conclude from these observations that titin is a strong regulator of muscle force and propose that this regulation is based on cross-bridge force-dependent titin-actin interactions. These results suggest a mechanism for stability of sarcomeres on the "inherently unstable" descending limb of the force-length relationship, and they further provide an explanation for the protection of muscles against stretch-induced muscle injuries. PMID:20357181

  10. A Fast Na+/Ca2+-Based Action Potential in a Marine Diatom

    PubMed Central

    Taylor, Alison R.

    2009-01-01

    Background Electrical impulses in animals play essential roles in co-ordinating an array of physiological functions including movement, secretion, environmental sensing and development. Underpinning many of these electrical signals is a fast Na+-based action potential that has been fully characterised only in cells associated with the neuromuscular systems of multicellular animals. Such rapid action potentials are thought to have evolved with the first metazoans, with cnidarians being the earliest representatives. The present study demonstrates that a unicellular protist, the marine diatom Odontella sinensis, can also generate a fast Na+/Ca2+ based action potential that has remarkably similar biophysical and pharmacological properties to invertebrates and vertebrate cardiac and skeletal muscle cells. Methodology/Principal Findings The kinetic, ionic and pharmacological properties of the rapid diatom action potential were examined using single electrode current and voltage clamp techniques. Overall, the characteristics of the fast diatom currents most closely resemble those of vertebrate and invertebrate muscle Na+/Ca2+ currents. Conclusions/Significance This is the first demonstration of voltage-activated Na+ channels and the capacity to generate fast Na+-based action potentials in a unicellular photosynthetic organism. The biophysical and pharmacological characteristics together with the presence of a voltage activated Na+/Ca2+ channel homologue in the recently sequenced genome of the diatom Thalassiosira pseudonana, provides direct evidence supporting the hypothesis that this rapid signalling mechanism arose in ancestral unicellular eukaryotes and has been retained in at least two phylogenetically distant lineages of eukaryotes; opisthokonts and the stramenopiles. The functional role of the fast animal-like action potential in diatoms remains to be elucidated but is likely involved in rapid environmental sensing of these widespread and successful marine protists

  11. Status and future transition of rapid urbanizing landscape in central Western Ghats - CA based approach

    NASA Astrophysics Data System (ADS)

    Bharath, S..; Rajan, K. S.; Ramachandra, T. V.

    2014-11-01

    The land use changes in forested landscape are highly complex and dynamic, affected by the natural, socio-economic, cultural, political and other factors. The remote sensing (RS) and geographical information system (GIS) techniques coupled with multi-criteria evaluation functions such as Markov-cellular automata (CA-Markov) model helps in analysing intensity, extent and future forecasting of human activities affecting the terrestrial biosphere. Karwar taluk of Central Western Ghats in Karnataka state, India has seen rapid transitions in its forest cover due to various anthropogenic activities, primarily driven by major industrial activities. A study based on Landsat and IRS derived data along with CA-Markov method has helped in characterizing the patterns and trends of land use changes over a period of 2004-2013, expected transitions was predicted for a set of scenarios through 2013-2022. The analysis reveals the loss of pristine forest cover from 75.51% to 67.36% (1973 to 2013) and increase in agriculture land as well as built-up area of 8.65% (2013), causing impact on local flora and fauna. The other factors driving these changes are the aggregated level of demand for land, local and regional effects of land use activities such as deforestation, improper practices in expansion of agriculture and infrastructure development, deteriorating natural resources availability. The spatio temporal models helped in visualizing on-going changes apart from prediction of likely changes. The CA-Markov based analysis provides us insights into the localized changes impacting these regions and can be useful in developing appropriate mitigation management approaches based on the modelled future impacts. This necessitates immediate measures for minimizing the future impacts.

  12. Model-Based Assessment of an In-Vivo Predictive Relationship from CA1 to CA3 in the Rodent Hippocampus

    PubMed Central

    Sandler, Roman A.; Song, Dong; Hampson, Robert E.; Deadwyler, Sam A.; Berger, Theodore W.; Marmarelis, Vasilis Z.

    2014-01-01

    Although an anatomical connection from CA1 to CA3 via the Entorhinal Cortex (EC) and through backprojecting interneurons has long been known it exist, it has never been examined quantitatively on the single neuron level, in the in-vivo nonpatholgical, nonperturbed brain. Here, single spike activity was recorded using a multi-electrode array from the CA3 and CA1 areas of the rodent hippocampus (N=7) during a behavioral task. The predictive power from CA3→CA1 and CA1→CA3 was examined by constructing Multivariate Autoregressive (MVAR) models from recorded neurons in both directions. All nonsignificant inputs and models were identified and removed by means of Monte Carlo simulation methods. It was found that 121/166 (73%) CA3→CA1 models and 96/145 (66%) CA1→CA3 models had significant predictive power, thus confirming a predictive ‘Granger’ causal relationship from CA1 to CA3. This relationship is thought to be caused by a combination of truly causal connections such as the CA1→EC→CA3 pathway and common inputs such as those from the Septum. All MVAR models were then examined in the frequency domain and it was found that CA3 kernels had significantly more power in the theta and beta range than those of CA1, confirming CA3’s role as an endogenous hippocampal pacemaker. PMID:25260381

  13. Characterization of flue gas cleaning residues from European solid waste incinerators: assessment of various Ca-based sorbent processes.

    PubMed

    Bodénan, F; Deniard, Ph

    2003-05-01

    For the first time, a set of samples of European flue gas cleaning residues, mainly from the incineration of municipal solid waste (MSW), has undergone a mineralogical study. The residues are the result of the neutralization of acid flue gases by lime, the predominant method adopted in Europe, using dry and semi-dry washing processes. The study protocol combines physico-chemical analytical techniques (XRD, FTIR, DSC/TGA) and global chemical analysis enabling identification of the chemical composition of the main constituents, particularly chlorinated Ca-based phases, as well as establishment of modal distributions of the represented phases, both crystalline and amorphous. The samples are slightly hydrated and values vary for trapped Cl, S and even CO(2). The main crystalline phases are NaCl, KCl, CaSO(4), CaCO(3), Ca(OH)(2) and calcium hydroxychloride CaOHCl. CaOHCl is the main chlorine phase, regardless of the treatment process, filtration mode, and specific surface of the Ca-based sorbent. This phase develops during neutralization of HCl by excess lime present according to the reaction Ca(OH)(2)+HCl-->CaOHCl+H(2)O, to the detriment of a complete yield involving the two lime OH groups with formation of CaCl(2).2H(2)O. In addition, it seems that gas temperatures above 150 degrees C increase competition between lime-based neutralization of HCl, SO(2) acid flue gases and CO(2) trapping, thus reducing washing efficiency. PMID:12597999

  14. Surface Roughness Model Based on Force Sensors for the Prediction of the Tool Wear

    PubMed Central

    de Agustina, Beatriz; Rubio, Eva María; Sebastián, Miguel Ángel

    2014-01-01

    In this study, a methodology has been developed with the objective of evaluating the surface roughness obtained during turning processes by measuring the signals detected by a force sensor under the same cutting conditions. In this way, the surface quality achieved along the process is correlated to several parameters of the cutting forces (thrust forces, feed forces and cutting forces), so the effect that the tool wear causes on the surface roughness is evaluated. In a first step, the best cutting conditions (cutting parameters and radius of tool) for a certain quality surface requirement were found for pieces of UNS A97075. Next, with this selection a model of surface roughness based on the cutting forces was developed for different states of wear that simulate the behaviour of the tool throughout its life. The validation of this model reveals that it was effective for approximately 70% of the surface roughness values obtained. PMID:24714391

  15. Sensorless Interaction Force Control Based on B-Spline Function for Human-Robot Systems

    NASA Astrophysics Data System (ADS)

    Mitsantisuk, Chowarit; Katsura, Seiichiro; Ohishi, Kiyoshi

    In this paper, to provide precise force sensation of human operator, a twin direct-drive motor system with wire rope mechanism has been developed. The human-robot interaction force and the wire rope tension are independently controlled in acceleration dimension by realizing the dual disturbance observer based on modal space design. In the common mode, it is utilized for control of vibration suppression and wire rope tension. In the differential mode, the purity of human external force with compensation of friction force is obtained. This mode is useful for control of the interaction force of human. Furthermore, the human-robot system that has the ability of support of human interaction force is also proposed. The interaction force generation based on B-spline function is applied to automatically adjust the smooth force command corresponding to the adaptive parameters.
    To analyze the human movement stroke, the multi-sensor scheme is applied to fuse both two motor encoders and acceleration sensor signal by using Kalman filter. From the experimental results, the ability to design different level of assistive force makes it well suited to customized training programs due to time and human movement constraints.

  16. The Sequential Evolution of Universes Based on Fundamental Forces

    NASA Astrophysics Data System (ADS)

    Derow, Catherine Kari

    2015-08-01

    Universes may arise as nature abhors a void. Upon ending of a universe, a new universe forms to fill a new void, forming after perhaps a period of nothingness.The nature of a new universe and the nature of formation, may be related to the nature of the previous universe and the nature of its ending, respectively, e.g., if the end of a universe was prolonged, this might be followed by a short period of nothingness and then an explosive creation of a new universe. Long approach to nothingness and a brief period of nothingness may mean a universe arises quickly and energetically in response to this long latent period of expectancy of void-filling. In terms of order in a universe, order may engender new more ordered universes, until need for chaos means a more chaotic universe arises. Ordered universes may cause new even more ordered universes to atise. The order principle dictates the type of matter organization that arises in universes in series. An ordered universe may have a latent energy of order which leads to a smaller more ordered universe. This minimizes the expectancy of a void, as a smaller more regularly filled void will then ensue in the new universe, until the energy held in by this order is released in the formation of a large much less ordered and slower forming and expanding universe, with more regions of near void. Nature may strive for a build up of intensity of focused order filling an ever- smaller void, averting the void, until the principle of chaos predominates and the energy that this requirement builds causes explosive formation of a large and disordered universe. The need to fill any void that arises and a force that favors a small void arising as void is abhorred and this void being regularly and densely filled competes with the force that favors matter tending towards chaos. These principles governs universes arising in series, until a period of nothingness can prevail until the need to create a void predominates. Nothingness is able to

  17. 5. METAL SHOP ROOM (AREA 108 ON PLAN CA236R36). Looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. METAL SHOP ROOM (AREA 108 ON PLAN CA-236-R-36). Looking northeast. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A Terminal Room, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  18. Acid-Base Interactions at the Molecular Level: Adhesion and Friction Studies with Interfacial Force Microscopy

    SciTech Connect

    Burns, A.R.; Carpick, R.W.; Houston, J.E.; Michalske, T.A.

    1998-12-09

    To examine the forces of acid-base adhesive interactions at the molecular level, we utilize the scanning probe Interracial Force Microscope (IFM). Unlike cantilever-based atomic force microscopes, the EM is a non-compliant, mechanically stable probe that provides a complete adhesive profile without jump-to-contact. In this way, we are able to quantitatively measure the work of adhesion and bond energies at well-defined, nanometer-scale single asperity contacts. In particular, we will discuss the displacement-controlled adhesive forces between self-assembled monolayer of functionalized alkanethiols strongly bound to a gold substrate and a similarly functionalized tip. We also discuss a method utilizing decoupled lateral and normal force sensors to simultaneously observe the onset of both friction and chemical bond formation. Measurements show that friction can be directly attributed to bond formation and rupture well before repulsive contact.

  19. Analysis and experimental evaluation of a Stewart platform-based force/torque sensor

    NASA Technical Reports Server (NTRS)

    Nguyen, Charles C.; Antrazi, Sami S.

    1992-01-01

    The kinematic analysis and experimentation of a force/torque sensor whose design is based on the mechanism of the Stewart Platform are discussed. Besides being used for measurement of forces/torques, the sensor also serves as a compliant platform which provides passive compliance during a robotic assembly task. It consists of two platforms, the upper compliant platform (UCP) and the lower compliant platform (LCP), coupled together through six spring-loaded pistons whose length variations are measured by six linear voltage differential transformers (LVDT) mounted along the pistons. Solutions to the forward and inverse kinematics of the force sensor are derived. Based on the known spring constant and the piston length changes, forces/torques applied to the LCP gripper are computed using vector algebra. Results of experiments conducted to evaluate the sensing capability of the force sensor are reported and discussed.

  20. 5. Credit USAF, ca. 1942. Original housed in the Photograph ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. Credit USAF, ca. 1942. Original housed in the Photograph Files, AFFTC/HO, Edwards AFB, California. View of Bell Aircraft XP-59A Airacomet in flight. This was the United States military's first jet propelled aircraft which was extensively flight tested in secrecy at the Muroc Flight Test Base (North Base). - Edwards Air Force Base, North Base, North Base Road, Boron, Kern County, CA

  1. Temporal Geophysical Investigations of the FT-2-Plume at the Wurtsmith Air Force Base, Oscoda, Michigan

    EPA Science Inventory

    The decommissioned Wurtsmith Air Force Base former Fire Training Cell (FT-02) facility has been the focus of several geophysical investigations. After several decades of fire training exercises, significant amounts of hydrocarbons and some solvents seeped into the subsurface cont...

  2. QUALITY MANAGEMENT DURING SELECTION OF TECHNOLOGIES EXAMPLE SITE MARCH AIR FORCE BASE, USA

    EPA Science Inventory

    This paper describes the remedial approach, organizational structure and key elements facilitating effective and efficient remediation of contaminated sites at March Air Force Base (AFB), California. The U.S. implementation and quality assurance approach to site remediation for ...

  3. QUALITY MANAGEMENT DURING SELECTION OF TECHNOLOGIES; EXAMPLE SITE MARCH AIR FORCE BASE, USA

    EPA Science Inventory

    This paper describes the remedial approach, organizational structure and key elements facilitating effective and efficient remediation of contaminated sites at March Air Force Base (AFB), California. The U.S. implementation and quality assurance approach to site remediation for a...

  4. (Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio)

    SciTech Connect

    Not Available

    1992-03-01

    This report contains information related to the sampling and chemical analysis of ground water at the Wright-Patterson Air Force Base. It is part of a field investigation of ground water contamination.

  5. Dyess Air Force Base, Atlas F Missle Site S8, Launch ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Dyess Air Force Base, Atlas F Missle Site S-8, Launch Control Center (LCC), Approximately 3 miles east of Winters, 500 feet southwest of Highway 17700, northwest of Launch Facility, Winters, Runnels County, TX

  6. TEMPORAL GEOPHYSICAL INVESTIGATIONS OF THE FT-2-PLUME AT THE WURTSMITH AIR FORCE BASE, OSCODA, MICHIGAN

    EPA Science Inventory

    The decommissioned Wurtsmith Air Force Base former Fire Training Cell (FT-02) facility has been the focus of several geophysical investigations. After several decades of fire training exercises, significant amounts of hydrocarbons and some solvents seeped into the Subsurface cont...

  7. (Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio)

    SciTech Connect

    Not Available

    1991-10-01

    This report presents information concerning field procedures employed during the monitoring, well construction, well purging, sampling, and well logging at the Wright-Patterson Air Force Base. Activities were conducted in an effort to evaluate ground water contamination.

  8. New method for assessment of gait variability based on wearable ground reaction force sensor.

    PubMed

    Liu, Tao; Inoue, Yoshio; Shibata, Kyoko

    2008-01-01

    In this paper, a new quantitative method of analyzing gait variability using a developed wearable ground reaction force (GRF) sensor system is presented. The design of the sensor system is based on the use of five small 3-axial sensors distributed on the underside of a shoe, so that in human dynamics analysis this system can continuously measure vertical pressure force and bio-directional friction forces referring to anterior-posterior friction force and mediolateral friction force. Compared to existing spatio-temporal evaluation methods using traditional force plates or instrumented treadmills, the new method was developed based on measurements of ambulatory or wearable force sensor which can continuously measure ground reaction force in various environments not limited to the laboratory environment. The area of the center of pressure (CoP) distribution on the foot-plate and the average coefficient of variation of the 3-axial GRF, which correlate strongly with the distribution of CoP, are suggested parameters for quantifying gait variability. To certify the effectiveness of these parameters, we conducted an experimental study on a group of volunteer subjects who walked under a designed experimental protocol. PMID:19163171

  9. A micropillar-based on-chip system for continuous force measurement of C. elegans

    NASA Astrophysics Data System (ADS)

    Ghanbari, Ali; Nock, Volker; Johari, Shazlina; Blaikie, Richard; Chen, XiaoQi; Wang, Wenhui

    2012-09-01

    Caenorhabditis elegans is a well-established model organism and has been gaining interest particularly related to worm locomotion and the investigation of the relationship between muscle arms and the motion pattern of the nematode. In this paper, we report on a micropillar-based on-chip system which is capable of quantifying multi-point locomotive forces of a moving C. elegans. A Polydimethylsiloxane (PDMS) device was microfabricated to allow C. elegans to move in a matrix of micropillars in a channel, and an image processing method was developed to resolve the worm force from the bending pillars. The current micropillar-based system is able to measure force with a resolution of 2.07 µN for body width of 80 µm. Initial experiments have been conducted to collect a maximum force level for thirteen wild type worm samples. A maximum force level of 61.94 µN was observed from 1571 data points, based on which an average maximum force level was 32.61 µN for multi-point measurements. The demonstrated capabilities of the system can be an enabling technology that allows biologist to gain a better understanding of subtle force patterns of C. elegans and worm muscle development.

  10. In vivo assessment of artery smooth muscle [Ca2+]i and MLCK activation in FRET-based biosensor mice

    PubMed Central

    Chen, Ling; Raina, Hema; Blaustein, Mordecai P.; Wier, W. Gil

    2010-01-01

    The cellular mechanisms that control arterial diameter in vivo, particularly in hypertension, are uncertain. Here, we report a method that permits arterial intracellular Ca2+ concentration ([Ca2+]i), myosin light-chain kinase (MLCK) activation, and artery external diameter to be recorded simultaneously with arterial blood pressure (BP) in living mice under 1.5% isofluorane anesthesia. The method also enables an assessment of local receptor activity on [Ca2+]i, MLCK activity, and diameter in arteries, uncomplicated by systemic effects. Transgenic mice that express, in smooth muscle, a Ca2+/calmodulin-activated, Förster resonance energy transfer (FRET)-based “ratiometric”, exogenous MLCK biosensor were used. Vasoactive substances were administered either intravenously or locally to segments of exposed femoral or cremaster arteries. In the basal state, mean BP was ∼90 mmHg, femoral arteries were constricted to 65% of their passive diameter, MLCK fractional activation was 0.14, and [Ca2+]i was 131 nM. Phenylephrine (300 ng/g wt iv) elevated mean BP transiently to ∼110 mmHg, decreased heart rate, increased femoral artery [Ca2+]i to 244 nM and fractional MLCK activation to 0.24, and decreased artery diameter by 23%. In comparison, local application of 1.0 μM phenylephrine raised [Ca2+]i to 279 nM and fractional MLCK activation to 0.26, and reduced diameter by 25%, but did not affect BP or heart rate. Intravital FRET imaging of exogenous MLCK biosensor mice permits quantification of changes in [Ca2+]i and MLCK activation that accompany small changes in BP. Based on the observed variance of the FRET data, this method should enable the detection of a difference in basal [Ca2+]i of 29 nM between two groups of 12 mice with a significance of P < 0.05. PMID:20622107

  11. 77 FR 30509 - Notice To Extend Public Comment Period for United States Air Force F-35A Operational Basing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-23

    ... Department of the Air Force Notice To Extend Public Comment Period for United States Air Force F-35A Operational Basing Environmental Impact Statement AGENCY: The United States Air Force, DoD. ACTION: Notification of Extension of Public Comment Period. SUMMARY: The U.S. Air Force is issuing this notice...

  12. Relativistic mean field model based on realistic nuclear forces

    SciTech Connect

    Hirose, S.; Serra, M.; Ring, P.; Otsuka, T.; Akaishi, Y.

    2007-02-15

    In order to predict properties of asymmetric nuclear matter, we construct a relativistic mean field (RMF) model consisting of one-meson exchange (OME) terms and point coupling (PC) terms. In order to determine the density dependent parameters of this model, we use properties of isospin symmetric nuclear matter in combination with the information on nucleon-nucleon scattering data, which are given in the form of the density dependent G-matrix derived from Brueckner calculations based on the Tamagaki potential. We show that the medium- and long-range components of this G-matrix can be described reasonably well by our effective OME interaction. In order to take into account the short-range part of the nucleon-nucleon interaction, which cannot be described well in this manner, a point coupling term is added. Its analytical form is taken from a model based on chiral perturbation theory. It contains only one additional parameter, which does not depend on the density. It is, together with the parameters of the OME potentials adjusted to the equation of state of symmetric nuclear matter. We apply this model for the investigation of asymmetric nuclear matter and find that the results for the symmetry energy as well as for the equation of state of pure neutron matter are in good agreement with either experimental data or with presently adopted theoretical predictions. In order to test the model at higher density, we use its equation of state for an investigation of properties of neutron stars.

  13. Structural basis for the in situ Ca2+ sensitization of cardiac troponin C by positive feedback from force-generating myosin cross-bridges

    PubMed Central

    Rieck, Daniel C.; Li, King-Lun; Ouyang, Yexin; Solaro, R. John; Dong, Wen-Ji

    2013-01-01

    The in situ structural coupling between the cardiac troponin (cTn) Ca2+-sensitive regulatory switch (CRS) and strong myosin cross-bridges was investigated using Förster resonance energy transfer (FRET). The double cysteine mutant cTnC(T13C/N51C) was fluorescently labeled with the FRET pair 5-(iodoacetamidoethyl)aminonaphthelene-1-sulfonic acid (IAEDENS) and N-(4-dimethylamino-3,5-dinitrophenyl)maleimide (DDPM) and then incorporated into detergent skinned left ventricular papillary fiber bundles. Ca2+ titrations of cTnC(T13C/N51C)AEDENS/DDPM-reconstituted fibers showed that the Ca2+-dependence of the opening of the N-domain of cTnC (N-cTnC) statistically matched the force–Ca2+ relationship. N-cTnC opening still occurred steeply during Ca2+ titrations in the presence of 1 mM vanadate, but the maximal extent of ensemble-averaged N-cTnC opening and the Ca2+-sensitivity of the CRS were significantly reduced. At nanomolar, resting Ca2+ levels, treatment with ADP•Mg in the absence of ATP caused a partial opening of N-cTnC. During subsequent Ca2+ titrations in the presence of ADP•Mg and absence of ATP, further N-cTnC opening was stimulated as the CRS responded to Ca2+ with increased Ca2+-sensitivity and reduced steepness. These findings supported our hypothesis here that strong cross-bridge interactions with the cardiac thin filament exert a Ca2+-sensitizing effect on the CRS by stabilizing the interaction between the exposed hydrophobic patch of N-cTnC and the switch region of cTnI. PMID:23896515

  14. Effect of cerium oxide doping on the performance of CaO-based sorbents during calcium looping cycles.

    PubMed

    Wang, Shengping; Fan, Shasha; Fan, Lijing; Zhao, Yujun; Ma, Xinbin

    2015-04-21

    A series of CaO-based sorbents were synthesized through a sol-gel method and doped with different amounts of CeO2. The sorbent with a Ca/Ce molar ratio of 15:1 showed an excellent absorption capacity (0.59 gCO2/g sorbent) and a remarkable cycle durability (up to 18 cycles). The admirable capture performance of CaCe-15 was ascribed to its special morphology formed by the doping of CeO2 and the well-distributed CeO2 particles. The sorbents doped with CeO2 possessed a loose shell-connected cross-linking structure, which was beneficial for the contact between CaO and CO2. CaO and CeO2 were dispersed homogeneously, and the existence of CeO2 also decreased the grain size of CaO. The well-dispersed CeO2, which could act as a barrier, effectively prevented the CaO crystallite from growing and sintering, thus the sorbent exhibited outstanding stability. The doping of CeO2 also improved the carbonation rate of the sorbent, resulting in a high capacity in a short period of time. PMID:25815798

  15. TMX1 determines cancer cell metabolism as a thiol-based modulator of ER-mitochondria Ca2+ flux.

    PubMed

    Raturi, Arun; Gutiérrez, Tomás; Ortiz-Sandoval, Carolina; Ruangkittisakul, Araya; Herrera-Cruz, Maria Sol; Rockley, Jeremy P; Gesson, Kevin; Ourdev, Dimitar; Lou, Phing-How; Lucchinetti, Eliana; Tahbaz, Nasser; Zaugg, Michael; Baksh, Shairaz; Ballanyi, Klaus; Simmen, Thomas

    2016-08-15

    The flux of Ca(2+) from the endoplasmic reticulum (ER) to mitochondria regulates mitochondria metabolism. Within tumor tissue, mitochondria metabolism is frequently repressed, leading to chemotherapy resistance and increased growth of the tumor mass. Therefore, altered ER-mitochondria Ca(2+) flux could be a cancer hallmark, but only a few regulatory proteins of this mechanism are currently known. One candidate is the redox-sensitive oxidoreductase TMX1 that is enriched on the mitochondria-associated membrane (MAM), the site of ER-mitochondria Ca(2+) flux. Our findings demonstrate that cancer cells with low TMX1 exhibit increased ER Ca(2+), accelerated cytosolic Ca(2+) clearance, and reduced Ca(2+) transfer to mitochondria. Thus, low levels of TMX1 reduce ER-mitochondria contacts, shift bioenergetics away from mitochondria, and accelerate tumor growth. For its role in intracellular ER-mitochondria Ca(2+) flux, TMX1 requires its thioredoxin motif and palmitoylation to target to the MAM. As a thiol-based tumor suppressor, TMX1 increases mitochondrial ATP production and apoptosis progression. PMID:27502484

  16. Flood-prone areas and waterways, Edwards Air Force Base, California

    USGS Publications Warehouse

    Meyer, Robert W.; Bowers, James C.

    2002-01-01

    Edwards Air Force Base (EAFB) is in the Mojave Desert region of southern California. Although the climate in the study area is arid, occasional intense storms result in flooding on the base, damaging roads and buildings. To plan for anticipated development at EAFB, the U.S. Department of the Air Force (USAF) and the U.S. Geological Survey (USGS) began a cooperative study to locate flood-prone areas on the base. This report describes flood hazards and shows flood-prone areas of the base.

  17. 9. Credit USAF, ca. 1955. Original housed in the Photograph ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. Credit USAF, ca. 1955. Original housed in the Photograph Files, AFFTC/HO, Edwards AFB, California. View of Lockheed XVF-1 Pogo, an experimental vertical take-off and landing aircraft at North Base. Photograph was taken on the apron between buildings 4401 and 4402, looking north northeast towards back of Building 4402 and officers' quarters (T-15) beyond. - Edwards Air Force Base, North Base, North Base Road, Boron, Kern County, CA

  18. A caGRID-ENABLED, LEARNING BASED IMAGE SEGMENTATION METHOD FOR HISTOPATHOLOGY SPECIMENS

    PubMed Central

    Foran, David J.; Yang, Lin; Tuzel, Oncel; Chen, Wenjin; Hu, Jun; Kurc, Tahsin M.; Ferreira, Renato; Saltz, Joel H.

    2009-01-01

    Accurate segmentation of tissue microarrays is a challenging topic because of some of the similarities exhibited by normal tissue and tumor regions. Processing speed is another consideration when dealing with imaged tissue microarrays as each microscopic slide may contain hundreds of digitized tissue discs. In this paper, a fast and accurate image segmentation algorithm is presented. Both a whole disc delineation algorithm and a learning based tumor region segmentation approach which utilizes multiple scale texton histograms are introduced. The algorithm is completely automatic and computationally efficient. The mean pixel-wise segmentation accuracy is about 90%. It requires about 1 second for whole disc (1024×1024 pixels) segmentation and less than 5 seconds for segmenting tumor regions. In order to enable remote access to the algorithm and collaborative studies, an analytical service is implemented using the caGrid infrastructure. This service wraps the algorithm and provides interfaces for remote clients to submit images for analysis and retrieve analysis results. PMID:19936299

  19. Discrimination Between Cervical Cancer Cells and Normal Cervical Cells Based on Longitudinal Elasticity Using Atomic Force Microscopy

    NASA Astrophysics Data System (ADS)

    Zhao, Xueqin; Zhong, Yunxin; Ye, Ting; Wang, Dajing; Mao, Bingwei

    2015-12-01

    The mechanical properties of cells are considered promising biomarkers for the early diagnosis of cancer. Recently, atomic force microscopy (AFM)-based nanoindentation technology has been utilized for the examination of cell cortex mechanics in order to distinguish malignant cells from normal cells. However, few attempts to evaluate the biomechanical properties of cells have focused on the quantification of the non-homogeneous longitudinal elasticity of cellular structures. In the present study, we applied a variation of the method of Carl and Schillers to investigate the differences between longitudinal elasticity of human cervical squamous carcinoma cells (CaSki) and normal cervical epithelial cells (CRL2614) using AFM. The results reveal a three-layer heterogeneous structure in the probing volume of both cell types studied. CaSki cells exhibited a lower whole-cell stiffness and a softer nuclei zone compared to the normal counterpart cells. Moreover, a better differentiated cytoskeleton was found in the inner cytoplasm/nuclei zone of the normal CRL2614 cells, whereas a deeper cytoskeletal distribution was observed in the probing volume of the cancerous counterparts. The sensitive cortical panel of CaSki cells, with a modulus of 0.35~0.47 kPa, was located at 237~225 nm; in normal cells, the elasticity was 1.20~1.32 kPa at 113~128 nm. The present improved method may be validated using the conventional Hertz-Sneddon method, which is widely reported in the literature. In conclusion, our results enable the quantification of the heterogeneous longitudinal elasticity of cancer cells, in particular the correlation with the corresponding depth. Preliminary results indicate that our method may potentially be applied to improve the detection of cancerous cells and provide insights into the pathophysiology of the disease.

  20. Discrimination Between Cervical Cancer Cells and Normal Cervical Cells Based on Longitudinal Elasticity Using Atomic Force Microscopy.

    PubMed

    Zhao, Xueqin; Zhong, Yunxin; Ye, Ting; Wang, Dajing; Mao, Bingwei

    2015-12-01

    The mechanical properties of cells are considered promising biomarkers for the early diagnosis of cancer. Recently, atomic force microscopy (AFM)-based nanoindentation technology has been utilized for the examination of cell cortex mechanics in order to distinguish malignant cells from normal cells. However, few attempts to evaluate the biomechanical properties of cells have focused on the quantification of the non-homogeneous longitudinal elasticity of cellular structures. In the present study, we applied a variation of the method of Carl and Schillers to investigate the differences between longitudinal elasticity of human cervical squamous carcinoma cells (CaSki) and normal cervical epithelial cells (CRL2614) using AFM. The results reveal a three-layer heterogeneous structure in the probing volume of both cell types studied. CaSki cells exhibited a lower whole-cell stiffness and a softer nuclei zone compared to the normal counterpart cells. Moreover, a better differentiated cytoskeleton was found in the inner cytoplasm/nuclei zone of the normal CRL2614 cells, whereas a deeper cytoskeletal distribution was observed in the probing volume of the cancerous counterparts. The sensitive cortical panel of CaSki cells, with a modulus of 0.35~0.47 kPa, was located at 237~225 nm; in normal cells, the elasticity was 1.20~1.32 kPa at 113~128 nm. The present improved method may be validated using the conventional Hertz-Sneddon method, which is widely reported in the literature. In conclusion, our results enable the quantification of the heterogeneous longitudinal elasticity of cancer cells, in particular the correlation with the corresponding depth. Preliminary results indicate that our method may potentially be applied to improve the detection of cancerous cells and provide insights into the pathophysiology of the disease. PMID:26666911

  1. Distributed forcing of the flow past a blunt-based axisymmetric bluff body

    NASA Astrophysics Data System (ADS)

    Jardin, Thierry; Bury, Yannick; DAEP Team

    2012-11-01

    The topology of bluff body wakes may be highly sensitive to forcing at frequencies close to intrinsic flow instabilities. In a similar way, a steady but spatially varying forcing at wavelengths close to specific flow instabilities can lead to analogous outcomes. Such forcing is commonly referred to as distributed forcing. However, although distributed forcing has proven to be a relevant control strategy for three-dimensional flows past nominally two-dimensional geometries (e.g. extruded circular cylinder at Re > 180), its impact on the flow past nominally three-dimensional geometries is still unknown. Here we assess the receptivity of the flow past a blunt-based axisymmetric bluff body to an azimuthally distributed forcing applied at the periphery of the bluff-body base. We show that the impact of RSPa, RSPb and RSPc instabilities on the drag fluctuations experienced by the bluff body can be suppressed, depending on the forcing wavelengths. The authors acknowledge the French Ministry of Defence and DGA for funding this work.

  2. Membrane-based actuation for high-speed single molecule force spectroscopy studies using AFM.

    PubMed

    Sarangapani, Krishna; Torun, Hamdi; Finkler, Ofer; Zhu, Cheng; Degertekin, Levent

    2010-07-01

    Atomic force microscopy (AFM)-based dynamic force spectroscopy of single molecular interactions involves characterizing unbinding/unfolding force distributions over a range of pulling speeds. Owing to their size and stiffness, AFM cantilevers are adversely affected by hydrodynamic forces, especially at pulling speeds >10 microm/s, when the viscous drag becomes comparable to the unbinding/unfolding forces. To circumvent these adverse effects, we have fabricated polymer-based membranes capable of actuating commercial AFM cantilevers at speeds >or=100 microm/s with minimal viscous drag effects. We have used FLUENT, a computational fluid dynamics (CFD) software, to simulate high-speed pulling and fast actuation of AFM cantilevers and membranes in different experimental configurations. The simulation results support the experimental findings on a variety of commercial AFM cantilevers and predict significant reduction in drag forces when membrane actuators are used. Unbinding force experiments involving human antibodies using these membranes demonstrate that it is possible to achieve bond loading rates >or=10(6) pN/s, an order of magnitude greater than that reported with commercial AFM cantilevers and systems. PMID:20054686

  3. Re-poling process for piezoelectric-based multilayer ceramic capacitors force sensor

    NASA Astrophysics Data System (ADS)

    Lin, Keng-Ren; Chang, Chih-Han; Chiang, Cheng-Hung; Lin, Che-Hsin

    2013-04-01

    This study presents an industrial-grade piezoelectric-based multilayer ceramic capacitors (MLCCs) force sensor. In order to increase the sensitivity and reduce the variation of different MLCCs, a simple re-poling process is adopted by applying an external electric field at the Curie temperature of MLCCs. Results indicate that the re-poling treatment improved up to 100-fold for the force detection sensitivity and reduced the variation for the output force response by 10-fold in comparison with the MLCC sensors without re-poling.

  4. Sliding mode-based lateral vehicle dynamics control using tyre force measurements

    NASA Astrophysics Data System (ADS)

    Kunnappillil Madhusudhanan, Anil; Corno, Matteo; Holweg, Edward

    2015-11-01

    In this work, a lateral vehicle dynamics control based on tyre force measurements is proposed. Most of the lateral vehicle dynamics control schemes are based on yaw rate whereas tyre forces are the most important variables in vehicle dynamics as tyres are the only contact points between the vehicle and road. In the proposed method, active front steering is employed to uniformly distribute the required lateral force among the front left and right tyres. The force distribution is quantified through the tyre utilisation coefficients. In order to address the nonlinearities and uncertainties of the vehicle model, a gain scheduling sliding-mode control technique is used. In addition to stabilising the lateral dynamics, the proposed controller is able to maintain maximum lateral acceleration. The proposed method is tested and validated on a multi-body vehicle simulator.

  5. Atomic-resolution single-spin magnetic resonance detection concept based on tunneling force microscopy

    NASA Astrophysics Data System (ADS)

    Payne, A.; Ambal, K.; Boehme, C.; Williams, C. C.

    2015-05-01

    A study of a force detected single-spin magnetic resonance measurement concept with atomic spatial resolution is presented. The method is based upon electrostatic force detection of spin-selection rule controlled single-electron tunneling between two electrically isolated paramagnetic states. Single-spin magnetic resonance detection is possible by measuring the force detected tunneling charge noise on and off spin resonance. Simulation results of this charge noise, based upon physical models of the tunneling and spin physics, are directly compared to measured atomic force microscopy system noise. The results show that the approach could provide single-spin measurement of electrically isolated qubit states with atomic spatial resolution at room temperature.

  6. Base-flow data in the Arnold Air Force Base area, Tennessee, June and October 2002

    USGS Publications Warehouse

    Robinson, John A.; Haugh, Connor J.

    2004-01-01

    Arnold Air Force Base (AAFB) occupies about 40,000 acres in Coffee and Franklin Counties, Tennessee. The primary mission of AAFB is to support the development of aerospace systems. This mission is accomplished through test facilities at Arnold Engineering Development Center (AEDC), which occupies about 4,000 acres in the center of AAFB. Base-flow data including discharge, temperature, and specific conductance were collected for basins in and near AAFB during high base-flow and low base-flow conditions. Data representing high base-flow conditions from 109 sites were collected on June 3 through 5, 2002, when discharge measurements at sites with flow ranged from 0.005 to 46.4 ft3/s. Data representing low base-flow conditions from 109 sites were collected on October 22 and 23, 2002, when discharge measurements at sites with flow ranged from 0.02 to 44.6 ft3/s. Discharge from the basin was greater during high base-flow conditions than during low base-flow conditions. In general, major tributaries on the north side and southeastern side of the study area (Duck River and Bradley Creek, respectively) had the highest flows during the study. Discharge data were used to categorize stream reaches and sub-basins. Stream reaches were categorized as gaining, losing, wet, dry, or unobserved for each base-flow measurement period. Gaining stream reaches were more common during the high base-flow period than during the low base-flow period. Dry stream reaches were more common during the low base-flow period than during the high base-flow period. Losing reaches were more predominant in Bradley Creek and Crumpton Creek. Values of flow per square mile for the study area of 0.55 and 0.37 (ft3/s)/mi2 were calculated using discharge data collected on June 3 through 5, 2002, and October 22 and 23, 2002, respectively. Sub-basin areas with surplus or deficient flow were defined within the basin. Drainage areas for each stream measurement site were delineated and measured from topographic maps

  7. Architecture-based force-velocity models of load-moving skeletal muscles.

    PubMed

    Baratta, R V; Solomonow, M; Best, R; Zembo, M; D'Ambrosia, R

    1995-04-01

    A predictive model of muscle force-velocity relationships is presented based on functional architectural variables. The parameters of Hill's equation describing muscle force-velocity relationship of nine muscles were estimated by their relationships with variables extracted from the whole-muscle length-force relationship and the percentage of slow-twitch fibres. Specifically, the maximal unloaded velocity (Vo) was estimated through multiple linear regression, from each muscle's fibre composition and the shortening range through which each muscle could produce active force. The maximal isometric force (Po) was also extracted from each muscle's length-force relationship. The ratio of Hill's dynamic constanta to Po and b to Vo, which determines the degree of curvature of the relation, was determined solely by the percent of slow-twitch fibres. This model was verified by fitting it to experimental force-velocity curves of nine different muscles in the cat's hindlimb. It was found that reasonable fits of force-velocity curves would be obtained with correlation coefficient in the range of 0.61 to 0.92, with an average of 0.82. The model predicted that muscles with relatively long shortening ranges would achieve higher maximal velocity, and that muscles with higher percentage of slow-twitch fibres had less pronounced curvature and lower maximal velocity in their force-velocity relationships. RELEVANCE: The results have direct implications in the design of neuroprosthetic limb control systems, which use electrical stimulation to restore function to muscles paralysed from spinal cord injury. The designer is enabled to optimally calibrate the controller according to the predicted individual force-velocity curves of different muscles by using the length-tension curves and fibre composition data available in the literature. PMID:11415546

  8. CO{sub 2} capture from flue gases using three Ca-based sorbents in a fluidized bed reactor

    SciTech Connect

    Li, Z.S.; Fang, F.; Cai, N.S.

    2009-06-15

    Abstract: Experiments of CO{sub 2} capture and sorbent regeneration characteristics of limestone, dolomite, and CaO/Ca{sub 1}2Al{sub 14}O{sub 3}3 at high temperature were investigated in a thermogravimetric analyzer (TGA) and a fluidized bed reactor. The effect of reactivity decay of limestone, dolomite, and CaO/Ca{sub 12}Al{sub 14}O{sub 3}3 sorbents on CO{sub 2} capture and sorbent regeneration processes was studied. The experimental results indicated that the operation time of high efficient CO{sub 2} capture stage declined continuously with increasing of the cyclic number due to the loss of the sorbent activity, and the final CO{sub 2} capture efficiency would remain nearly constant, due to the sorbent already reaching the final residual capture capacity. After the CO{sub 2} capture step, the Ca-based sorbents need to be regenerated to be used for a subsequent cycle, and the multiple calcination processes of Ca-based sorbent under different calcination conditions are studied and discussed. Reactivity loss of limestone, dolomite and CaO/Ca{sub 12}Al{sub 14}O{sub 3}3 sorbents from a fluidized bed reactor at both mild and severe calcination conditions was compared with the TGA data. At mild calcination conditions, TGA results of sorbent reactivity loss were similar to the experimental results of fluidized bed reactor for three sorbents at 850 degrees C calcination temperature, and this indicated that TGA experimental results can be used as a reference to predict sorbent reactivity loss behavior in fluidized bed reactor. At severe calcination condition, sorbent reactivity loss behavior for limestone and dolomite from TGA compare well with the result from a fluidized bed reactor.

  9. 33 CFR 334.630 - Tampa Bay south of MacDill Air Force Base, Fla.; small-arms firing range and aircraft jettison, U...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base...″, longitude 82°33′02.44″; and thence to a point on the shore line of MacDill Air Force Base at latitude...

  10. 33 CFR 334.630 - Tampa Bay south of MacDill Air Force Base, Fla.; small-arms firing range and aircraft jettison, U...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base...″, longitude 82°33′02.44″; and thence to a point on the shore line of MacDill Air Force Base at latitude...

  11. 33 CFR 334.630 - Tampa Bay south of MacDill Air Force Base, Fla.; small-arms firing range and aircraft jettison, U...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base...″, longitude 82°33′02.44″; and thence to a point on the shore line of MacDill Air Force Base at latitude...

  12. 33 CFR 334.630 - Tampa Bay south of MacDill Air Force Base, Fla.; small-arms firing range and aircraft jettison, U...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base...″, longitude 82°33′02.44″; and thence to a point on the shore line of MacDill Air Force Base at latitude...

  13. 33 CFR 334.630 - Tampa Bay south of MacDill Air Force Base, Fla.; small-arms firing range and aircraft jettison, U...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base...″, longitude 82°33′02.44″; and thence to a point on the shore line of MacDill Air Force Base at latitude...

  14. High precision deflection measurement of microcantilever in an optical pickup head based atomic force microscopy

    SciTech Connect

    Lee, Sang Heon

    2012-11-15

    This paper presents the methodology to measure the precise deflection of microcantilever in an optical pickup head based atomic force microscopy. In this paper, three types of calibration methods have been proposed: full linearization, sectioned linearization, and the method based on astigmatism. In addition, the probe heads for easy calibration of optical pickup head and fast replacement of optical pickup head have been developed. The performances of each method have been compared through a set of experiments and constant height mode operation which was not possible in the optical pickup head based atomic force microscopy has been carried out successfully.

  15. 33 CFR 165.1102 - Security Zone; Naval Base Point Loma; San Diego Bay, San Diego, CA.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    .... (b) Regulations. (1) The general regulations governing security zones found in 33 CFR 165.33 apply to... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Security Zone; Naval Base Point... Guard District § 165.1102 Security Zone; Naval Base Point Loma; San Diego Bay, San Diego, CA....

  16. Testing a Non-Competency Inservice Education Model Based on Humanistic or Third Force Psychology

    ERIC Educational Resources Information Center

    Beck, William

    1978-01-01

    The investigation of the impact of the "growth" approach, based on humanistic or Third Force psychology, involved developing a "growth" model based on humanistic psychology, pilot "testing" the model, and drawing implications regarding the model's potential for inservice education. The data indicated that the "growth" approach to inservice…

  17. Force-based optimization of pseudopotentials for non-equilibrium configurations

    NASA Astrophysics Data System (ADS)

    Brock, Casey N.; Paikoff, Brandon C.; Md Sallih, Muhammad I.; Tackett, Alan R.; Walker, D. Greg

    2016-04-01

    We have used a multi-objective genetic algorithm to optimize pseudopotentials for force accuracy and computational efficiency. Force accuracy is determined by comparing interatomic forces generated using the pseudopotentials and forces generated using the full-potential linearized augmented-plane wave method. This force-based optimization approach is motivated by applications where interatomic forces are important, including material interfaces, crystal defects, and molecular dynamics. Our method generates Pareto sets of optimized pseudopotentials containing various compromises between accuracy and efficiency. We have tested our method for LiF, Si0.5Ge0.5, and Mo and compared the performance of our pseudopotentials with pseudopotentials available from the ABINIT library. We show that the optimization can generate pseudopotentials with comparable accuracy (in terms of force matching and equation of state) to pseudopotentials in the literature while sometimes significantly improving computational efficiency. For example, we generated pseudopotentials for one system tested that reduced computational work by 71% without loss of accuracy. These results suggest our method can be used to generate pseudopotentials on demand that are tuned for a user's specific application, affording gains in computational efficiency.

  18. Experimental study of frost heaving force based on transient shock response using piezoceramic sensors

    NASA Astrophysics Data System (ADS)

    Wang, Ruolin; Peng, Tongxiao; Wang, Ming L.

    2016-04-01

    In seasonally frozen soil regions, the frost heaving problem made it difficult to monitor or evaluate the pile safety for long term. So far, no mature tool can be utilized to monitor the frost heaving force, which was unevenly distributed along the pile. In this paper, a piezoceramic sensing based transient excitation response approach was proposed to monitor the frost heaving force in real time. Freeze-thaw cycles can result in great changes of soil engineering properties, including the frost heaving force. So, the freeze-thaw cycle was repeated fourth to study its effect. In the experiment, transient horizontal shock on the top of the pile will be detected by the 6 PZT sensors glued on the pile. The signal data received by the 6 PZT sensors can be used to illustrate the frost heaving force distribution along the pile. Moisture content effect is also one of the important reasons that cause the variation of soil mechanical properties. So three different moisture content (6%, 12%, 18%) testing soil were used in this experiment to detect the variance of the frost heaving force. An energy indicator was developed to quantitatively evaluate the frost heaving force applied on the pile. The experimental results showed that the proposed method was effective in monitoring the uneven distribution of frost heaving force along the pile.

  19. 33 CFR 334.750 - Ben's Lake, a tributary of Choctawhatchee Bay, Fla., at Eglin Air Force Base; restricted area.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Choctawhatchee Bay, Fla., at Eglin Air Force Base; restricted area. 334.750 Section 334.750 Navigation and... RESTRICTED AREA REGULATIONS § 334.750 Ben's Lake, a tributary of Choctawhatchee Bay, Fla., at Eglin Air Force..., without the permission of the Commander, Eglin Air Force Base, Florida, or his authorized...

  20. 33 CFR 334.750 - Ben's Lake, a tributary of Choctawhatchee Bay, Fla., at Eglin Air Force Base; restricted area.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Choctawhatchee Bay, Fla., at Eglin Air Force Base; restricted area. 334.750 Section 334.750 Navigation and... RESTRICTED AREA REGULATIONS § 334.750 Ben's Lake, a tributary of Choctawhatchee Bay, Fla., at Eglin Air Force..., without the permission of the Commander, Eglin Air Force Base, Florida, or his authorized...

  1. 8. Credit USAF, ca. 1952. Original housed in the Photograph ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Credit USAF, ca. 1952. Original housed in the Photograph Files, AFFTC/HO, Edwards AFB, California. Oblique low-level aerial view of North Base looking northeast. Based on positions and types of aircraft and automobiles, this photo taken same day as HAER photo CA-170-7. Most temporary structures in this view have been demolished with the exception of the hangars. The concrete foundations remain of many structures, while no trace was found of others. - Edwards Air Force Base, North Base, North Base Road, Boron, Kern County, CA

  2. Development of a quartz tuning-fork-based force sensor for measurements in the tens of nanoNewton force range during nanomanipulation experiments

    SciTech Connect

    Oiko, V. T. A. Rodrigues, V.; Ugarte, D.; Martins, B. V. C.; Silva, P. C.

    2014-03-15

    Understanding the mechanical properties of nanoscale systems requires new experimental and theoretical tools. In particular, force sensors compatible with nanomechanical testing experiments and with sensitivity in the nN range are required. Here, we report the development and testing of a tuning-fork-based force sensor for in situ nanomanipulation experiments inside a scanning electron microscope. The sensor uses a very simple design for the electronics and it allows the direct and quantitative force measurement in the 1–100 nN force range. The sensor response is initially calibrated against a nN range force standard, as, for example, a calibrated Atomic Force Microscopy cantilever; subsequently, applied force values can be directly derived using only the electric signals generated by the tuning fork. Using a homemade nanomanipulator, the quantitative force sensor has been used to analyze the mechanical deformation of multi-walled carbon nanotube bundles, where we analyzed forces in the 5–40 nN range, measured with an error bar of a few nN.

  3. A large area tactile sensor patch based on commercial force sensors.

    PubMed

    Vidal-Verdú, Fernando; Barquero, Maria Jose; Castellanos-Ramos, Julián; Navas-González, Rafael; Sánchez, Jose Antonio; Serón, Javier; García-Cerezo, Alfonso

    2011-01-01

    This paper reports the design of a tactile sensor patch to cover large areas of robots and machines that interact with human beings. Many devices have been proposed to meet such a demand. These realizations are mostly custom-built or developed in the lab. The sensor of this paper is implemented with commercial force sensors. This has the benefit of a more foreseeable response of the sensor if its behavior is understood as the aggregation of readings from all the individual force sensors in the array. A few reported large area tactile sensors are also based on commercial sensors. However, the one in this paper is the first of this kind based on the use of polymeric commercial force sensing resistors (FSR) as unit elements of the array or tactels, which results in a robust sensor. The paper discusses design issues related to some necessary modifications of the force sensor, its assembly in an array, and the signal conditioning. The patch has 16 × 9 force sensors mounted on a flexible printed circuit board with a spatial resolution of 18.5 mm. The force range of a tactel is 6 N and its sensitivity is 0.6 V/N. The array is read at a rate of 78 frames per second. Finally, two simple application examples are also carried out with the sensor mounted on the forearm of a rescue robot that communicates with the sensor through a CAN bus. PMID:22163910

  4. Vision-based force measurement using neural networks for biological cell microinjection.

    PubMed

    Karimirad, Fatemeh; Chauhan, Sunita; Shirinzadeh, Bijan

    2014-03-21

    This paper presents a vision-based force measurement method using an artificial neural network model. The proposed model is used for measuring the applied load to a spherical biological cell during micromanipulation process. The devised vision-based method is most useful when force measurement capability is required, but it is very challenging or even infeasible to use a force sensor. Artificial neural networks in conjunction with image processing techniques have been used to estimate the applied load to a cell. A bio-micromanipulation system capable of force measurement has also been established in order to collect the training data required for the proposed neural network model. The geometric characterization of zebrafish embryos membranes has been performed during the penetration of the micropipette prior to piercing. The geometric features are extracted from images using image processing techniques. These features have been used to describe the shape and quantify the deformation of the cell at different indentation depths. The neural network is trained by taking the visual data as the input and the measured corresponding force as the output. Once the neural network is trained with sufficient number of data, it can be used as a precise sensor in bio-micromanipulation setups. However, the proposed neural network model is applicable for indentation of any other spherical elastic object. The results demonstrate the capability of the proposed method. The outcomes of this study could be useful for measuring force in biological cell micromanipulation processes such as injection of the mouse oocyte/embryo. PMID:24411067

  5. A Large Area Tactile Sensor Patch Based on Commercial Force Sensors

    PubMed Central

    Vidal-Verdú, Fernando; Barquero, Maria Jose; Castellanos-Ramos, Julián; Navas-González, Rafael; Sánchez, Jose Antonio; Serón, Javier; García-Cerezo, Alfonso

    2011-01-01

    This paper reports the design of a tactile sensor patch to cover large areas of robots and machines that interact with human beings. Many devices have been proposed to meet such a demand. These realizations are mostly custom-built or developed in the lab. The sensor of this paper is implemented with commercial force sensors. This has the benefit of a more foreseeable response of the sensor if its behavior is understood as the aggregation of readings from all the individual force sensors in the array. A few reported large area tactile sensors are also based on commercial sensors. However, the one in this paper is the first of this kind based on the use of polymeric commercial force sensing resistors (FSR) as unit elements of the array or tactels, which results in a robust sensor. The paper discusses design issues related to some necessary modifications of the force sensor, its assembly in an array, and the signal conditioning. The patch has 16 × 9 force sensors mounted on a flexible printed circuit board with a spatial resolution of 18.5 mm. The force range of a tactel is 6 N and its sensitivity is 0.6 V/N. The array is read at a rate of 78 frames per second. Finally, two simple application examples are also carried out with the sensor mounted on the forearm of a rescue robot that communicates with the sensor through a CAN bus. PMID:22163910

  6. Finite Element Method Based Modeling for Prediction of Cutting Forces in Micro-end Milling

    NASA Astrophysics Data System (ADS)

    Pratap, Tej; Patra, Karali

    2016-04-01

    Micro-end milling is one of the widely used processes for producing micro features/components in micro-fluidic systems, biomedical applications, aerospace applications, electronics and many more fields. However in these applications, the forces generated in the micro-end milling process can cause tool vibration, process instability and even cause tool breakage if not minimized. Therefore, an accurate prediction of cutting forces in micro-end milling is essential. In this work, a finite element method based model is developed using ABAQUS/Explicit 6.12 software for prediction of cutting forces in micro-end milling with due consideration of tool edge radius effect, thermo-mechanical properties and failure parameters of the workpiece material including friction behaviour at tool-chip interface. Experiments have been performed for manufacturing of microchannels on copper plate using 500 µm diameter tungsten carbide micro-end mill and cutting forces are acquired through a dynamometer. Predicted cutting forces in feed and cross feed directions are compared with experimental results and are found to be in good agreements. Results also show that FEM based simulations can be applied to analyze size effects of specific cutting forces in micro-end milling process.

  7. Reporting a new siderophore based Ca(2+) selective chemosensor that works as a staining agent in the live organism Artemia.

    PubMed

    Raju, M; Nair, Ratish R; Raval, Ishan H; Haldar, Soumya; Chatterjee, Pabitra B

    2015-11-21

    A Ca(2+)-specific chemosensor involving acyclic non-ether and non-carboxylato-type metal chelating ligands is rare. The tetradentate OONO artificial receptor, HL, possessing a sulfur-containing intermediate siderophore aeruginic acid, tethered to a rhodamine 6G based signalling unit in a single molecule has been synthesized. The fluoroionophore required excitation in the visible wavelength (510 nm) and showed highly selective and sensitive detection of Ca(2+) ions in 100% water solution in HEPES buffer at physiological pH (7.4). The probe HL, with LOD as low as 70 nM, behaves reversibly and showed nearly 17-fold enhanced selectivity for Ca(2+) over other cell abundant alkali and alkaline metal ions such as Na(+), K(+), Li(+), and Mg(2+) without any intervention. Job's plot, (1)H NMR titration and ESI-MS data provided corroborative evidence in support of 1 : 1 association between HL and Ca(2+). From a wide range of transition and heavy metal ions series, HL also binds Cu(2+). However, the use of l-cysteine removes the interference from Cu(2+) and results in highly selective detection specificity of HL for Ca(2+). As a reversible "off-on-off" fluorescent chemosensor, it is possible to detect Ca(2+) at as low as 5 μM in the midgut region of the gastrointestinal tract of the live animal Artemia, a brine shrimp. PMID:26460620

  8. Estimation of cable tension force using the frequency-based system identification method

    NASA Astrophysics Data System (ADS)

    Kim, Byeong Hwa; Park, Taehyo

    2007-07-01

    This work proposes a new technique to estimate cable tension force from measured natural frequencies. The proposed method is able to simultaneously identify tension force, flexural rigidity, and axial rigidity of a cable system. Firstly, a finite element model that can consider both sag-extensibility and flexural rigidity is constructed for a target cable system. Next, a frequency-based sensitivity-updating algorithm is applied to identify the model. The proposed approach is applicable to a wide range of a cable system that is beyond the applicable limits of the existing methods. From the experimental works, it is seen that the tension force is determined with an accuracy of 3% by the proposed approach. Furthermore, it is observed that the flexural rigidity of cable with high bending stiffness is proportional to the applied tension force.

  9. Reciprocity-based experimental determination of dynamic forces and moments: A feasibility study

    NASA Technical Reports Server (NTRS)

    Ver, Istvan L.; Howe, Michael S.

    1994-01-01

    BBN Systems and Technologies has been tasked by the Georgia Tech Research Center to carry Task Assignment No. 7 for the NASA Langley Research Center to explore the feasibility of 'In-Situ Experimental Evaluation of the Source Strength of Complex Vibration Sources Utilizing Reciprocity.' The task was carried out under NASA Contract No. NAS1-19061. In flight it is not feasible to connect the vibration sources to their mounting points on the fuselage through force gauges to measure dynamic forces and moments directly. However, it is possible to measure the interior sound field or vibration response caused by these structureborne sound sources at many locations and invoke principle of reciprocity to predict the dynamic forces and moments. The work carried out in the framework of Task 7 was directed to explore the feasibility of reciprocity-based measurements of vibration forces and moments.

  10. A new facility to realize a nanonewton force standard based on electrostatic methods

    NASA Astrophysics Data System (ADS)

    Nesterov, V.; Mueller, M.; Frumin, L. L.; Brand, U.

    2009-06-01

    A new differential nanoforce facility, based on a disc-pendulum with electrostatic stiffness reduction and an electrostatic force compensation for the measurement of horizontal forces in the range below 1 µN, is presented. First measurements in air over an averaging time of 50 s show a noise level of the facility of 42 pN. The method and the results of measuring the light pressure of a red He-Ne laser with a power of 7 mW (FL = 47 pN) are presented. The force measurement uncertainty of the device is below 5%, for a force to be measured of 1 nN and a measuring duration of 50 s.

  11. REACTION MECHANISMS OF DRY CA-BASED SORBENTS WITH GASEOUS HCL

    EPA Science Inventory

    The paper discusses an investigation of the mechanisms of HCl reaction with dry Ca(OH)2 or CaO sorbents in flue gas cleaning applications using differential scanning calorimetry (DSC), thermogravimetry (TGA), and X-ray diffraction (XRD). hort-time differential reactor (STDR) was ...

  12. REACTION MECHANISMS OF DRY CA-BASED SORBENTS WITH GASEOUS HCL

    EPA Science Inventory

    The mechanisms of HC1 reaction with dry Ca(OH)2 or CaO sorbents in flue gas cleaning applications were investigated by differential scanning calorimetry (DSC), thermogravimetry, and X-ray diffraction. A short-time differential reactor (STDR) was used to contact 1000 ...

  13. Multiparametric imaging of biological systems by force-distance curve-based AFM.

    PubMed

    Dufrêne, Yves F; Martínez-Martín, David; Medalsy, Izhar; Alsteens, David; Müller, Daniel J

    2013-09-01

    A current challenge in the life sciences is to understand how biological systems change their structural, biophysical and chemical properties to adjust functionality. Addressing this issue has been severely hampered by the lack of methods capable of imaging biosystems at high resolution while simultaneously mapping their multiple properties. Recent developments in force-distance (FD) curve-based atomic force microscopy (AFM) now enable researchers to combine (sub)molecular imaging with quantitative mapping of physical, chemical and biological interactions. Here we discuss the principles and applications of advanced FD-based AFM tools for the quantitative multiparametric characterization of complex cellular and biomolecular systems under physiological conditions. PMID:23985731

  14. The double K+/Ca2+ sensor based on laser scanned silicon transducer (LSST) for multi-component analysis.

    PubMed

    Ermolenko, Yu; Yoshinobu, T; Mourzina, Yu; Furuichi, K; Levichev, S; Schöning, M J; Vlasov, Yu; Iwasaki, H

    2003-03-10

    In the present work a double ion sensor based on a laser scanned semiconductor transducer (LSST) for the simultaneous determination of K(+)- and Ca(2+)-ions in solutions has been developed. Specially elaborated ion-sensitive membrane compositions based on valinomycin and calcium ionophore calcium bis[4-(1,1,3,3-tetramethylbutyl)phenyl] phosphate (t-HDOPP-Ca) were deposited as separate layers on a silanized surface of the Si/SiO(2)/Si(3)N(4)-transducer. The proposed multi-sensor exhibits theoretical sensitivities and the detection limits of the sensor were found to be 2 x 10(-6) mol l(-1) for K(+) and 5 x 10(-6) mol l(-1) for Ca(2+). The elaborated double sensor is proposed for the first time as a prototype of a new type of multi-sensor systems for chemical analysis. PMID:18968966

  15. Contact-flatted measurement of eye stiffness based on force-displacement relationship

    NASA Astrophysics Data System (ADS)

    Zhang, Jin; Ma, Jianguo; Zhang, Xueyong

    2011-12-01

    This paper presents a noninvasive approach in vivo measurement of eye stiffness based on a force-displacement relationship, which is based on a new contact-probe method of simultaneously measuring the static force and displacement. First, a simple spherical eye model is introduced for deriving analytical eye stiffness when a static force is applied to an eye. Next, a measurement system for simultaneously measuring force and displacement when a probe is pressed onto the eye is presented. Static eye stiffness is defined which based on the measured force-displacement relationship. A photoelectric probe transducer acts as displacement detector. A 16-bit single-chip microprocessor with E2PROM in the electronic circuit played the role of a nucleus, which stored the program instructions and the interrelated data. Laboratory experiments were carried out on a simulated eyeball connected to a hydraulic manometer to obtain intraocular pressure at different levels. The experimental results show that the measured eye stiffness nicely matches the analytical result.

  16. A system for simultaneously measuring contact force, ultrasound, and position information for use in force-based correction of freehand scanning.

    PubMed

    Burcher, Michael R; Noble, J Alison; Han, Lianghao; Gooding, Mark

    2005-08-01

    During freehand ultrasound imaging, the sonographer places the ultrasound probe on the patient's skin. This paper describes a system that simultaneously records the position of the probe, the contact force between the probe and skin, and the ultrasound image. The system consists of an ultrasound machine, a probe, a force sensor, an optical localizer, and a host computer. Two new calibration methods are demonstrated: a temporal calibration to determine the time delay between force and position measurements, and a gravitational calibration to remove the effect of gravity on the recorded force. Measurements made with the system showed good agreement with those obtained from a standard materials testing machine. The system's uses include three-dimensional (3-D) ultrasound imaging, force-based deformation correction of ultrasound images, and indentation testing. PMID:16245602

  17. CaO-based pellets supported by calcium aluminate cements for high-temperature CO2 capture.

    PubMed

    Manovic, Vasilije; Anthony, Edward J

    2009-09-15

    The development of highly efficient CaO-based pellet sorbents, using inexpensive raw materials (limestones) or the spent sorbent from CO2 capture cycles, and commercially available calcium aluminate cements (CA-14, CA-25, Secar 51, and Secar 80), is described here. The pellets were prepared using untreated powdered limestones or their corresponding hydrated limes and were tested for their CO2 capture carrying capacities for 30 carbonation/calcination cycles in a thermogravimetric analyzer (TGA). Their morphology was also investigated by scanning electron microscopy (SEM) and their compositions before and after carbonation/calcination cycleswere determined by X-ray diffraction (XRD). Pellets prepared in this manner showed superior behavior during CO2 capture cycles compared to natural sorbents, with the highest conversions being > 50% after 30 cycles. This improved performance was attributed to the resulting substructure of the sorbent particles, i.e., a porous structure with nanoparticles incorporated. During carbonation/calcination cycles mayenite (Ca12Al14O33) was formed, which is believed to be responsible for the favorable performance of synthetic CaO-based sorbents doped with alumina compounds. An added advantage of the pellets produced here is their superior strength, offering the possibility of using them in fluidized bed combustion (FBC) systems with minimal sorbent loss due to attrition. PMID:19806751

  18. Atomistic insight into orthoborate-based ionic liquids: force field development and evaluation.

    PubMed

    Wang, Yong-Lei; Shah, Faiz Ullah; Glavatskih, Sergei; Antzutkin, Oleg N; Laaksonen, Aatto

    2014-07-24

    We have developed an all-atomistic force field for a new class of halogen-free chelated orthoborate-phosphonium ionic liquids. The force field is based on an AMBER framework with determination of force field parameters for phosphorus and boron atoms, as well as refinement of several available parameters. The bond and angle force constants were adjusted to fit vibration frequency data derived from both experimental measurements and ab initio calculations. The force field parameters for several dihedral angles were obtained by fitting torsion energy profiles deduced from ab initio calculations. To validate the proposed force field parameters, atomistic simulations were performed for 12 ionic liquids consisting of tetraalkylphosphonium cations and chelated orthoborate anions. The predicted densities for neat ionic liquids and the [P6,6,6,14][BOB] sample, with a water content of approximately 2.3-2.5 wt %, are in excellent agreement with available experimental data. The potential energy components of 12 ionic liquids were discussed in detail. The radial distribution functions and spatial distribution functions were analyzed and visualized to probe the microscopic ionic structures of these ionic liquids. There are mainly four high-probability regions of chelated orthoborate anions distributed around tetraalkylphosphonium cations in the first solvation shell, and such probability distribution functions are strongly influenced by the size of anions. PMID:25020237

  19. DNA-based digital tension probes reveal integrin forces during early cell adhesion

    PubMed Central

    Zhang, Yun; Ge, Chenghao; Zhu, Cheng; Salaita, Khalid

    2014-01-01

    Mechanical stimuli profoundly alter cell fate, yet the mechanisms underlying mechanotransduction remain obscure due to a lack of methods for molecular force imaging. Here, to address this need, we develop a new class of molecular tension probes that function as a switch to generate a 20–30-fold increase in fluorescence upon experiencing a threshold piconewton force. The probes employ immobilized DNA-hairpins with tunable force response thresholds, ligands, and fluorescence reporters. Quantitative imaging reveals that integrin tension is highly dynamic and increases with an increasing integrin density during adhesion formation. Mixtures of fluorophore-encoded probes show integrin mechanical preference for cyclized-RGD over linear-RGD peptides. Multiplexed probes with variable guanine-cytosine content within their hairpins reveal integrin preference for the more stable probes at the leading tip of growing adhesions near the cell edge. DNA-based tension probes are among the most sensitive optical force reporters to date, overcoming the force and spatial-resolution limitations of traction force microscopy. PMID:25342432

  20. Label-Free Sensing of Adenosine Based on Force Variations Induced by Molecular Recognition

    PubMed Central

    Li, Jingfeng; Li, Qing; Colombi Ciacchi, Lucio; Wei, Gang

    2015-01-01

    We demonstrate a simple force-based label-free strategy for the highly sensitive sensing of adenosine. An adenosine ssDNA aptamer was bound onto an atomic force microscopy (AFM) probe by covalent modification, and the molecular-interface adsorption force between the aptamer and a flat graphite surface was measured by single-molecule force spectroscopy (SMFS). In the presence of adenosine, the molecular recognition between adenosine and the aptamer resulted in the formation of a folded, hairpin-like DNA structure and hence caused a variation of the adsorption force at the graphite/water interface. The sensitive force response to molecular recognition provided an adenosine detection limit in the range of 0.1 to 1 nM. The addition of guanosine, cytidine, and uridine had no significant interference with the sensing of adenosine, indicating a strong selectivity of this sensor architecture. In addition, operational parameters that may affect the sensor, such as loading rate and solution ionic strength, were investigated. PMID:25808841

  1. Mechanical dynamics in live cells and fluorescence-based force/tension sensors

    PubMed Central

    Yang, Chao; Zhang, Xiaohan; Guo, Yichen; Meng, Fanjie; Sachs, Frederick; Guo, Jun

    2016-01-01

    Three signaling systems play the fundamental roles in modulating cell activities: chemical, electrical, and mechanical. While the former two are well studied, the mechanical signaling system is still elusive because of the lack of methods to measure structural forces in real time at cellular and subcellular levels. Indeed, almost all biological processes are responsive to modulation by mechanical forces that trigger dispersive downstream electrical and biochemical pathways. Communication among the three systems is essential to make cells and tissues receptive to environmental changes. Cells have evolved many sophisticated mechanisms for the generation, perception and transduction of mechanical forces, including motor proteins and mechanosensors. In this review, we introduce some background information about mechanical dynamics in live cells, including the ubiquitous mechanical activity, various types of mechanical stimuli exerted on cells and the different mechanosensors. We also summarize recent results obtained using genetically encoded FRET (fluorescence resonance energy transfer)-based force/tension sensors; a new technique used to measure mechanical forces in structural proteins. The sensors have been incorporated into many specific structural proteins and have measured the force gradients in real time within live cells, tissues, and animals. PMID:25958335

  2. 7. Credit USAF, ca. 1952. Original housed in the Photograph ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Credit USAF, ca. 1952. Original housed in the Photograph Files, AFFTC/HO, Edwards AFB, California. Oblique aerial view of North Base AFFTC (Air Force Flight Test Center) looking west northwest. The flight line at the edge of Rogers Dry Lake appears in the foreground, served by the facility's four hangars. Temporary structures beyond the hangars were demolished later in the 1950s. The fence that formerly surrounded the swimming pool in earlier photos has been taken down. In the distance lies the Jet Propulsion Laboratory Edwards Test Station, in its pre-1953 configuration. - Edwards Air Force Base, North Base, North Base Road, Boron, Kern County, CA

  3. Proceedings: The Conference of the University/Urban Schools National Task Force: What Works in Urban Schools (3rd, San Francisco, CA, July 9-10, 1982).

    ERIC Educational Resources Information Center

    Bossone, Richard M., Ed.

    Proceedings of the University/Urban Schools Task Force conference on what works in urban schools are summarized in this report. The future direction of the Task Force, articulated by conference participants, is described as a move toward the conceptualization and design of programs to teach thinking skills versus programs that mainly teach subject…

  4. A Novel Graphene Oxide-Based Protein Interaction Measurement Using Atomic Force Microscopy.

    PubMed

    Han, Sung-Woong; Morita, Kyohei; Adachi, Taiji

    2015-02-01

    Graphene oxide (GO) is a promising material for biological applications because of its excellent physical/chemical properties such as aqueous processability, amphiphilicity, and surface functionalizability. Here we introduce a new biological application of GO, a novel GO-based technique for probing protein interactions using atomic force microscopy (AFM). GO sheets were intercalated between the protein-modified AFM probe and the polymer substrate in order to reduce the non-specific adhesion force observed during single-molecule force spectroscopy (SMFS). In this study, we used SMFS to probe the interaction of the actin filament and actin-related protein 2/3 complex (Arp2/3), an actin-binding protein. Our results confirm that the GO sheet reduces nonspecific adhesion of the probe to the substrate. Using the GO-based technique, we succeeded in estimating the dissociation constant of the actin filament-binding protein interaction. PMID:26353630

  5. AFM-based force spectroscopy measurements of mature amyloid fibrils of the peptide glucagon

    NASA Astrophysics Data System (ADS)

    Dong, Mingdong; Bruun Hovgaard, Mads; Mamdouh, Wael; Xu, Sailong; Otzen, Daniel Erik; Besenbacher, Flemming

    2008-09-01

    We report on the mechanical characterization of individual mature amyloid fibrils by atomic force microscopy (AFM) and AFM-based single-molecule force spectroscopy (SMFS). These self-assembling materials, formed from the 29-residue amphiphatic peptide hormone glucagon, were found to display a reversible elastic behaviour. Based on AFM morphology and SMFS studies, we suggest that the observed elasticity is due to a force-induced conformational transition which is reversible due to the β-helical conformation of protofibrils, allowing a high degree of extension. The elastic properties of such mature fibrils contribute to their high stability, suggesting that the internal hydrophobic interactions of amyloid fibrils are likely to be of fundamental importance in the assembly of amyloid fibrils and therefore for the understanding of the progression of their associated pathogenic disorders. In addition, such biological amyloid fibril structures with highly stable mechanical properties can potentially be used to produce nanofibres (nanowires) that may be suitable for nanotechnological applications.

  6. Feedforward suppression of force ripple based on a simplex-optimized dither signal.

    PubMed

    Tan, K K; Chin, S J; Dou, H F

    2003-01-01

    This paper presents the design and realization of a feedforward dither signal to reduce the force ripple in an iron-core permanent magnet linear motor (PMLM). A composite control structure is used, consisting of three components: a simple feedforward component, a PID feedback component, and a ripple compensator (RC). The first two components are designed based on a dominant linear model of the motor. The dither signal is generated based on a signal model which is identified using a multidimensional simplex downhill method. In this way, a simple approach is available to eliminate or suppress the inherent force ripple, thus facilitating smooth precise motion while uncompromising on the maximum force achievable. Real-time experimental results verify the effectiveness of the proposed scheme for high precision motion trajectory tracking. PMID:12546465

  7. Creep force modelling for rail traction vehicles based on the Fastsim algorithm

    NASA Astrophysics Data System (ADS)

    Spiryagin, Maksym; Polach, Oldrich; Cole, Colin

    2013-11-01

    The evaluation of creep forces is a complex task and their calculation is a time-consuming process for multibody simulation (MBS). A methodology of creep forces modelling at large traction creepages has been proposed by Polach [Creep forces in simulations of traction vehicles running on adhesion limit. Wear. 2005;258:992-1000; Influence of locomotive tractive effort on the forces between wheel and rail. Veh Syst Dyn. 2001(Suppl);35:7-22] adapting his previously published algorithm [Polach O. A fast wheel-rail forces calculation computer code. Veh Syst Dyn. 1999(Suppl);33:728-739]. The most common method for creep force modelling used by software packages for MBS of running dynamics is the Fastsim algorithm by Kalker [A fast algorithm for the simplified theory of rolling contact. Veh Syst Dyn. 1982;11:1-13]. However, the Fastsim code has some limitations which do not allow modelling the creep force - creep characteristic in agreement with measurements for locomotives and other high-power traction vehicles, mainly for large traction creep at low-adhesion conditions. This paper describes a newly developed methodology based on a variable contact flexibility increasing with the ratio of the slip area to the area of adhesion. This variable contact flexibility is introduced in a modification of Kalker's code Fastsim by replacing the constant Kalker's reduction factor, widely used in MBS, by a variable reduction factor together with a slip-velocity-dependent friction coefficient decreasing with increasing global creepage. The proposed methodology is presented in this work and compared with measurements for different locomotives. The modification allows use of the well recognised Fastsim code for simulation of creep forces at large creepages in agreement with measurements without modifying the proven modelling methodology at small creepages.

  8. A pre-conditioned implicit direct forcing based immersed boundary method for incompressible viscous flows

    NASA Astrophysics Data System (ADS)

    Park, Hyunwook; Pan, Xiaomin; Lee, Changhoon; Choi, Jung-Il

    2016-06-01

    A novel immersed boundary (IB) method based on an implicit direct forcing (IDF) scheme is developed for incompressible viscous flows. The key idea for the present IDF method is to use a block LU decomposition technique in momentum equations with Taylor series expansion to construct the implicit IB forcing in a recurrence form, which imposes more accurate no-slip boundary conditions on the IB surface. To accelerate the IB forcing convergence during the iterative procedure, a pre-conditioner matrix is introduced in the recurrence formulation of the IB forcing. A Jacobi-type parameter is determined in the pre-conditioner matrix by minimizing the Frobenius norm of the matrix function representing the difference between the IB forcing solution matrix and the pre-conditioner matrix. In addition, the pre-conditioning parameter is restricted due to the numerical stability in the recurrence formulation. Consequently, the present pre-conditioned IDF (PIDF) enables accurate calculation of the IB forcing within a few iterations. We perform numerical simulations of two-dimensional flows around a circular cylinder and three-dimensional flows around a sphere for low and moderate Reynolds numbers. The result shows that PIDF yields a better imposition of no-slip boundary conditions on the IB surfaces for low Reynolds number with a fairly larger time step than IB methods with different direct forcing schemes due to the implicit treatment of the diffusion term for determining the IB forcing. Finally, we demonstrate the robustness of the present PIDF scheme by numerical simulations of flow around a circular array of cylinders, flows around a falling sphere, and two sedimenting spheres in gravity.

  9. O(-) identified at high temperatures in CaO-based catalysts for oxidative methane dimerization

    NASA Technical Reports Server (NTRS)

    Freund, F.; Maiti, G. C.; Batllo, F.; Baerns, M.

    1990-01-01

    A technique called charge-distribution analysis (CDA) is employed to study mobile charge carriers in the oxidation catalysts CaO, CaO with 11 percent Na2O, and CaO with 10 percent La2O3. A threshold temperature of about 550-600 C is identified at which highly mobile charge carriers are present, and the CDA studies show that they are O(-) states. The present investigation indicates the usefulness of CDA in catalysis research with pressed powder samples and gas/solid reactions.

  10. 77 FR 33210 - EDF Industrial Power Services (CA), LLC; Supplemental Notice That Initial Market-Based Rate...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-05

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission EDF Industrial Power Services (CA), LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced...

  11. Lift vs. drag based mechanisms for vertical force production in the smallest flying insects.

    PubMed

    Jones, S K; Laurenza, R; Hedrick, T L; Griffith, B E; Miller, L A

    2015-11-01

    We used computational fluid dynamics to determine whether lift- or drag-based mechanisms generate the most vertical force in the flight of the smallest insects. These insects fly at Re on the order of 4-60 where viscous effects are significant. Detailed quantitative data on the wing kinematics of the smallest insects is not available, and as a result both drag- and lift-based strategies have been suggested as the mechanisms by which these insects stay aloft. We used the immersed boundary method to solve the fully-coupled fluid-structure interaction problem of a flexible wing immersed in a two-dimensional viscous fluid to compare three idealized hovering kinematics: a drag-based stroke in the vertical plane, a lift-based stroke in the horizontal plane, and a hybrid stroke on a tilted plane. Our results suggest that at higher Re, a lift-based strategy produces more vertical force than a drag-based strategy. At the Re pertinent to small insect hovering, however, there is little difference in performance between the two strategies. A drag-based mechanism of flight could produce more vertical force than a lift-based mechanism for insects at Re<5; however, we are unaware of active fliers at this scale. PMID:26300066

  12. A force measurement instrument for optical tweezers based on the detection of light momentum changes

    NASA Astrophysics Data System (ADS)

    Farré, Arnau; Marsà, Ferran; Montes-Usategui, Mario

    2014-09-01

    In this work, we present and discuss several developments implemented in an instrument that uses the detection of the light momentum change for measuring forces in an optical trap. A system based on this principle provides a direct determination of this magnitude regardless of the positional response of the sample under the effect of an external force, and it is therefore to be preferred when in situ calibrations of the trap stiffness are not attainable or are difficult to achieve. The possibility to obtain this information without relying upon a harmonic model of the force is more general and can be used in a wider range of situations. Forces can be measured on non-spherical samples or non-Gaussian beams, on complex and changing environments, such as the interior of cells, or on samples with unknown properties (size, viscosity, etc.). However, the practical implementation of the method entails some difficulties due to the strict conditions in the design and operation of an instrument based on this method. We have focused on some particularly conflicting points. We developed a process and a mechanism to determine and systematically set the correct axial position of the device. We further analyzed and corrected the non-uniform transmittance of the optical system and we finally compensated for the variations in the sensor responsivity with temperature. With all these improvements, we obtained an accuracy of ~5% in force measurements for samples of different kinds.

  13. Analyzing excitation forces acting on a plate based on measured acoustic pressure.

    PubMed

    Wu, Sean F; Zhou, Pan

    2016-07-01

    This paper presents a theoretical study on "seeing" through an elastic structure to uncover the root cause of sound and vibration by using nearfield acoustical holography (NAH) and normal modes expansion. This approach is of generality because vibro-acoustic responses on the surface of a vibrating structure can always be reconstructed, exactly or approximately. With these vibro-acoustic responses, excitation forces acting on the structure can always be determined, analytically or numerically, given any set of boundary conditions. As an example, the explicit formulations for reconstructing time-harmonic excitation forces, including point, line and surface forces, and their arbitrary combinations acting on a rectangular thin plate in vacuum mounted on an infinite baffle are presented. The reason for choosing this example is that the analytic solutions to vibro-acoustic responses are available, and in-depth analyses of results are possible. Results demonstrate that this approach allows one to identify excitation forces based on measured acoustic pressures and reveal their characteristics such as locations, types and amplitudes, as if one could "see" excitation forces acting behind the plate based on acoustic pressure measured on the opposite side. This approach is extendable to general elastic structures, except that in such circumstance numerical results must be sought. PMID:27475174

  14. Two-dimensional electrostatic force field measurements with simultaneous topography measurement on embedded interdigitated nanoelectrodes using a force distance curve based method

    NASA Astrophysics Data System (ADS)

    Jenke, Martin Günter; Santschi, Christian; Hoffmann, Patrik

    2008-02-01

    Accurate simultaneous measurements on the topography and electrostatic force field of 500nm pitch interdigitated electrodes embedded in a thin SiO2 layer in a plane perpendicular to the orientation of the electrodes are shown for the first time. A static force distance curve (FDC) based method has been developed, which allows a lateral and vertical resolution of 25 and 2nm, respectively. The measured force field distribution remains stable as result of the well controlled fabrication procedure of Pt cantilever tips that allows thousands of FDC measurements. A numerical model is established as well which demonstrates good agreement with the experimental results.

  15. CaF2-Based Near-Infrared Photocatalyst Using the Multifunctional CaTiO3 Precursors as the Calcium Source.

    PubMed

    Huang, Shouqiang; Guo, Shengjuan; Wang, Qingji; Zhu, Nanwen; Lou, Ziyang; Li, Liang; Shan, Aidang; Yuan, Haiping

    2015-09-16

    Multistage formation of fluoride upconversion agents from the related-semiconductor precursors provides a promising route for the fabrication of near-infrared (NIR) photocatalysts with high photocatalytic activities. Herein, the cotton templated CaTiO3 "semiconduction" precursors (C-CaTiO3) were used to synthesize the NIR photocatalyst of Er3+/Tm3+/Yb3+-(CaTiO3/CaF2/TiO2) (C-ETYCCT), and the functions of the Ca2+ source for CaF2 and the heterostructure formations were displayed by C-CaTiO3. The generated CaF2 acted as the host material for the lanthanide ions, and the heterostructures were constructed among anatase, rutile, and the remaining CaTiO3. The induced oxygen vacancies and Ti3+ ions enabled the samples to utilize most of the upconversion luminescence for photocatalysis. The NIR driven degradation rate of methyl orange (MO) over C-ETYCCT reached 52.34%, which was 1.6 and 2.5 times higher than those of Er3+/Tm3+/Yb3+-(CaTiO3/TiO2) (C-ETYCT) and Er3+/Tm3+/Yb3+-(CaTiO3/CaF2) (C-ETYCC), respectively. The degradation rates of MO and salicylic acid over C-ETYCCT with UV-vis-NIR light irradiation were also much higher than those of other samples, which were mainly results of the contributions of its high upconversion luminescence and the efficient electron-hole pair separation. PMID:26305907

  16. STEAM ENHANCED REMEDIATION RESEARCH FOR DNAPL IN FRACTURED ROCK, LORING AIR FORCE BASE, LIMESTONE, MAINE

    EPA Science Inventory

    This report details a research project on Steam Enhanced Remediation (SER) for the recovery of volatile organic compounds from fractured limestone that was carried out at the Quarry at the former Loring Air Force Base in Limestone, Maine. This project was carried out by USEPA, Ma...

  17. NATURAL ATTENUATION OF CHLORINATED SOLVENTS AT MULTIPLE AIR FORCE BASE DEMONSTRATION SITES

    EPA Science Inventory

    Natural attenuation treatability studies(TSs) were conducted at 14 US Air Force bases. Only sites where biodegradation of CAHs was suspected were selected for the study. The major initiative was to evaluate the effectiveness of monitored natural attenuation(MNA) at sites contam...

  18. Landing of STS-59 Shuttle Endeavour at Edwards Air Force Base

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The main landing gear of the Space Shuttle Endeavour touches down at Edwards Air Force Base to complete the 11 day STS-59/SRL-1 mission. Landing occured at 9:54 a.m., April 20, 1994. Mission duration was 11 days, 5 hours, 49 minutes.

  19. THE GROUNDWATER GEOCHEMISTRY OF AREA 6, DOVER AIR FORCE BASE, DOVER, DELAWARE

    EPA Science Inventory

    This report reviews and interprets groundwater chemistry data collected at the Dover Air Force Base (AFB), Area 6, from July 1995 through March 1997. The work was conducted as part of the Remediation Technologies Development Forum (RTDF) Bioremediation of Chlorinated Solvents Ac...

  20. SIMULATION OF INTRINSIC BIOREMEDIATION PROCESSES AT WURTSMITH AIR FORCE BASE, MICHIGAN

    EPA Science Inventory

    In October, 1988, a KC-135 aircraft crashed at Wurtsmith Air Force base (AFB), Oscoda, Michigan during an attempted landing. Approximately 3000 gallons of jet fuel (JP-4) were spilled onto the ground, with a large portion of the fuel entering the subsurface. Previous investigat...

  1. (Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio)

    SciTech Connect

    Not Available

    1992-03-01

    This report presents information related to the sampling of ground water at the Wright-Patterson Air Force Base. It is part of an investigation into possible ground water contamination. Information concerns well drilling/construction; x-ray diffraction and sampling; soil boring logs; and chain-of-custody records.

  2. A long telephoto lens captured Space Shuttle Endeavour landing at Edwards Air Force Base, California

    NASA Technical Reports Server (NTRS)

    2001-01-01

    A long telephoto lens captured Space Shuttle Endeavour landing at Edwards Air Force Base, California, on May 1, 2001. NASA's Dryden Flight Research Center at Edwards would subsequently service the shuttle and mount it on a 747 for the ferry flight to the Kennedy Space Center in Florida.

  3. Analysis of vector wind change with respect to time for Vandenberg Air Force Base, California

    NASA Technical Reports Server (NTRS)

    Adelfang, S. I.

    1978-01-01

    A statistical analysis of the temporal variability of wind vectors at 1 km altitude intervals from 0 to 27 km altitude taken from a 10-year data sample of twice-daily rawinsode wind measurements over Vandenberg Air Force Base, California is presented.

  4. Applying Model Analysis to a Resource-Based Analysis of the Force and Motion Conceptual Evaluation

    ERIC Educational Resources Information Center

    Smith, Trevor I.; Wittmann, Michael C.; Carter, Tom

    2014-01-01

    Previously, we analyzed the Force and Motion Conceptual Evaluation in terms of a resources-based model that allows for clustering of questions so as to provide useful information on how students correctly or incorrectly reason about physics. In this paper, we apply model analysis to show that the associated model plots provide more information…

  5. FEASIBILITY OF PRODUCING COMMODITIES AND ELECTRICITY FOR SPACE SHUTTLE OPERATIONS AT VANDENBERG AIR FORCE BASE

    EPA Science Inventory

    The report gives results of a preliminary screening study of the technical and economic feasibility of the on-site production of commodities (liquid propellant and gases) and electricity to support space shuttle launch activities at Vandenberg Air Force Base (VAFB). Both commerci...

  6. BIOREMEDIATION FIELD EVALUATION: EIELSON AIR FORCE BASE, ALASKA (EPA/540/R-95/533)

    EPA Science Inventory

    This publication, one of a series presenting the findings of the Bioremediation Field Initiatives bioremediation field evaluations, provides a detailed summary of the evaluation conducted at the Eielson Air Force Base (AFB) Superfund site in Fairbanks, Alaska. At this site, the ...

  7. The Impact of Acquiescence on Forced-Choice Responses: A Model-Based Analysis

    ERIC Educational Resources Information Center

    Ferrando, Pere J.; Anguiano-Carrasco, Cristina; Chico, Eliseo

    2011-01-01

    The general aim of the present study is to assess the potential usefulness of the normative Forced Choice (FC) format for reducing the impact of acquiescent responding (AR). To this end it makes two types of contributions: methodological and substantive. Methodologically, it proposes a model-based procedure, derived from a basic response…

  8. A neutron scintillator based on transparent nanocrystalline CaF2:Eu glass ceramic

    NASA Astrophysics Data System (ADS)

    Struebing, Christian; Chong, JooYun; Lee, Gyuhyon; Zavala, Martin; Erickson, Anna; Ding, Yong; Wang, Cai-Lin; Diawara, Yacouba; Engels, Ralf; Wagner, Brent; Kang, Zhitao

    2016-04-01

    There are no efficient Eu2+ doped glass neutron scintillators reported due to low doping concentrations of Eu2+ and the amorphous nature of the glass matrix. In this work, an efficient CaF2:Eu glass ceramic neutron scintillator was prepared by forming CaF2:Eu nanocrystals in a 6Li-containing glass matrix. Through appropriate thermal treatments, the scintillation light yield of the transparent glass ceramic was increased by a factor of at least 46 compared to the as-cast amorphous glass. This improvement was attributed to more efficient energy transfer from the CaF2 crystals to the Eu2+ emitting centers. Further light yield improvement is expected if the refractive index of the glass matrix can be matched to the CaF2 crystal.

  9. Effect of storage conditions on handling and SO2 reactivity of CA(OH)2-based sorbents

    SciTech Connect

    Jozewicz, W.; Gullett, B.K.

    1991-01-01

    The article gives results of an investigation of the effect of relative humidity (RH), time, and aeration during calcium hydroxide--Ca(OH)2--storage for its effect on sorbent handling and reactivity with sulfur dioxide (SO2). Investigated was the effect of sorbent storage conditions of time (1-24 hr), RH (zero-90%), silo wall material, and aeration on handling properties of flowability and floodability and their subsequent effect on sorbent/SO2 reactivity. Increased RH in the storage chamber and prolonged storage increased floodability, as predicted by the angle of difference. No significant effect of RH on the flowability of Ca(OH)2, as predicted by the angle of repose, was detected. The importance of silo wall material on proper sorbent discharge pattern has been demonstrated through testing on four common surfaces. The effect of sorbent storage conditions on the reactivity of Ca(OH)2 with SO2 was evaluated in a short time differential reactor (STDR)operated under conditions typical of dry sorbent injection for SO2 control near the preheater. Increased RH and aeration with air during storage resulted in decreased reactivity of Ca(OH)2 with SO2. The effect of storage conditions on handling of novel Ca(OH)2-based sorbents for the removal of SO2 was also evaluated. ADVACATE sorbent appears to have significantly better handling properties than the other sorbents tested.

  10. Ground-water conditions at Beale Air Force Base and vicinity, California

    USGS Publications Warehouse

    Page, R.W.

    1980-01-01

    Ground-water conditions were studied in a 168-square-mile area between the Sierra Nevada and the Feather River in Yuba County, Calif. The area is in the eastern part of the Sacramento Valley and includes most of Beale Air Force Base. Source, occurrence, movement, and chemical quality of the ground water were evaluated. Ground water occurs in sedimentary and volcanic rocks of Tertiary and Quaternary age. The base of the freshwater is in the undifferentiated sedimentary rocks of Oligocene and Eocene age, that contain water of high dissolved-solids concentration. The ground water occurs under unconfined and partly confined conditions. At Beale Air Force Base it is at times partly confined. Recharge is principally from the rivers. Pumpage in the study area was estimated to be 129,000 acre-feet in 1975. In the 1960's, water levels in most parts of the study area declined less rapidly than in earlier years or became fairly stable. In the 1970's, water levels at Beale Air Force Base declined only slightly. Spacing of wells on the base and rates of pumping are such that excessive pumping interference is avoided. Water quality at the base and throughout the study area is generally good. Dissolved-solids concentrations are 700 to 900 milligrams per liter in the undifferentiated sedimentary rocks beneath the base well field. (USGS)

  11. Multiparametric high-resolution imaging of native proteins by force-distance curve-based AFM.

    PubMed

    Pfreundschuh, Moritz; Martinez-Martin, David; Mulvihill, Estefania; Wegmann, Susanne; Muller, Daniel J

    2014-05-01

    A current challenge in the life sciences is to understand how the properties of individual molecular machines adjust in order to meet the functional requirements of the cell. Recent developments in force-distance (FD) curve-based atomic force microscopy (FD-based AFM) enable researchers to combine sub-nanometer imaging with quantitative mapping of physical, chemical and biological properties. Here we present a protocol to apply FD-based AFM to the multiparametric imaging of native proteins under physiological conditions. We describe procedures for experimental FD-based AFM setup, high-resolution imaging of proteins in the native unperturbed state with simultaneous quantitative mapping of multiple parameters, and data interpretation and analysis. The protocol, which can be completed in 1-3 d, enables researchers to image proteins and protein complexes in the native unperturbed state and to simultaneously map their biophysical and biochemical properties at sub-nanometer resolution. PMID:24743419

  12. Data on wells in the Edwards Air Force Base area, California

    USGS Publications Warehouse

    Dutcher, L.C.; Bader, J.S.; Hiltgen, W.J.

    1962-01-01

    The data presented In this report were collected by the U.S. Geological Survey as a phase of the investigation of ground-water geology and hydrology of the Edwards Air Force Base area. The study was made in cooperation with the Department of the Air Force but also was coincident with the U.S. Geological Survey investigation of water wells and general hydrologic conditions throughout much of the desert region of southern California. The overall study of general hydrologic conditions in the desert is part of a cooperative program with the California Department of Water Resources.

  13. Force/torque and tactile sensors for sensor-based manipulator control

    NASA Technical Reports Server (NTRS)

    Vanbrussel, H.; Belieen, H.; Bao, Chao-Ying

    1989-01-01

    The autonomy of manipulators, in space and in industrial environments, can be dramatically enhanced by the use of force/torque and tactile sensors. The development and future use of a six-component force/torque sensor for the Hermes Robot Arm (HERA) Basic End-Effector (BEE) is discussed. Then a multifunctional gripper system based on tactile sensors is described. The basic transducing element of the sensor is a sheet of pressure-sensitive polymer. Tactile image processing algorithms for slip detection, object position estimation, and object recognition are described.

  14. Mountain Home Air Force Base, Idaho Geothermal Resource Assessment and Future Recommendations

    SciTech Connect

    Joseph C. Armstrong; Robert P. Breckenridge; Dennis L. Nielson; John W. Shervais; Thomas R. Wood

    2013-03-01

    The U.S. Air Force is facing a number of challenges as it moves into the future, one of the biggest being how to provide safe and secure energy to support base operations. A team of scientists and engineers met at Mountain Home Air Force Base in early 2011 near Boise, Idaho, to discuss the possibility of exploring for geothermal resources under the base. The team identified that there was a reasonable potential for geothermal resources based on data from an existing well. In addition, a regional gravity map helped identify several possible locations for drilling a new well. The team identified several possible sources of funding for this well—the most logical being to use U.S. Department of Energy funds to drill the upper half of the well and U.S. Air Force funds to drill the bottom half of the well. The well was designed as a slimhole well in accordance with State of Idaho Department of Water Resources rules and regulations. Drilling operations commenced at the Mountain Home site in July of 2011 and were completed in January of 2012. Temperatures increased gradually, especially below a depth of 2000 ft. Temperatures increased more rapidly below a depth of 5500 ft. The bottom of the well is at 5976 ft, where a temperature of about 140°C was recorded. The well flowed artesian from a depth below 5600 ft, until it was plugged off with drilling mud. Core samples were collected from the well and are being analyzed to help understand permeability at depth. Additional tests using a televiewer system will be run to evaluate orientation and directions at fractures, especially in the production zone. A final report on the well exploitation will be forthcoming later this year. The Air Force will use it to evaluate the geothermal resource potential for future private development options at Mountain Home Air Force Base. In conclusion, Recommendation for follow-up efforts include the following:

  15. An automated electrophysiological assay for differentiating Ca(v)2.2 inhibitors based on state dependence and kinetics.

    PubMed

    Swensen, Andrew M; Niforatos, Wende; Vortherms, Timothy A; Perner, Richard J; Li, Tao; Schrimpf, Michael R; Scott, Victoria E; Lee, Lance; Jarvis, Michael F; McGaraughty, Steve

    2012-12-01

    Ca(V)2.2 (N-type) calcium channels are key regulators of neurotransmission. Evidence from knockout animals and localization studies suggest that Ca(V)2.2 channels play a critical role in nociceptive transmission. Additionally, ziconotide, a selective peptide inhibitor of Ca(V)2.2 channels, is clinically used to treat refractory pain. However, the use of ziconotide is limited by its low therapeutic index, which is believed, at least in part, to be a consequence of ziconotide inhibiting Ca(V)2.2 channels regardless of the channel state. Subsequent efforts have focused on the discovery of state-dependent inhibitors that preferentially bind to the inactivated state of Ca(V)2.2 channels in order to achieve an improved safety profile relative to ziconotide. Much less attention has been paid to understanding the binding kinetics of these state-dependent inhibitors. Here, we describe a novel electrophysiology-based assay on an automated patch platform designed to differentiate Ca(V)2.2 inhibitors based on their combined state dependence and kinetics. More specifically, this assay assesses inactivated state block, closed state block, and monitors the kinetics of recovery from block when channels move between states. Additionally, a use-dependent assay is described that uses a train of depolarizing pulses to drive channels to a similar level of inactivation for comparison. This use-dependent protocol also provides information on the kinetics of block development. Data are provided to show how these assays can be utilized to screen for kinetic diversity within and across chemical classes. PMID:22428804

  16. Wave-based control of under-actuated flexible structures with strong external disturbing forces

    NASA Astrophysics Data System (ADS)

    O'Connor, William J.; Habibi, Hossein

    2015-09-01

    Wave-based control of under-actuated, flexible systems has many advantages over other methods. It considers actuator motion as launching a mechanical wave into the flexible system which it absorbs on its return to the actuator. The launching and absorbing proceed simultaneously. This simple, intuitive idea leads to robust, generic, highly efficient, precise, adaptable controllers, allowing rapid and almost vibrationless re-positioning of the system, using only sensors collocated at the actuator-system interface. It has been very successfully applied to simple systems such as mass-spring strings, systems of Euler-Bernoulli beams, planar mass-spring arrays, and flexible three-dimensional space structures undergoing slewing motion. In common with most other approaches, this work also assumed that, during a change of position, the forces from the environment were negligible in comparison with internal forces and torques. This assumption is not always valid. Strong external forces considerably complicate the flexible control problem, especially when unknown, unexpected or unmodelled. The current work extends the wave-based strategy to systems experiencing significant external disturbing forces, whether enduring or transient. The work also provides further robustness to sensor errors. The strategy has the controller learn about the disturbances and compensate for them, yet without needing new sensors, measurements or models beyond those of standard wave-based control.

  17. A noncontact force sensor based on a fiber Bragg grating and its application for corrosion measurement.

    PubMed

    Pacheco, Clara J; Bruno, Antonio C

    2013-01-01

    A simple noncontact force sensor based on an optical fiber Bragg grating attached to a small magnet has been proposed and built. The sensor measures the force between the magnet and any ferromagnetic material placed within a few millimeters of the sensor. Maintaining the sensor at a constant standoff distance, material loss due to corrosion increases the distance between the magnet and the corroded surface, which decreases the magnetic force. This will decrease the strain in the optical fiber shifting the reflected Bragg wavelength. The measured shift for the optical fiber used was 1.36 nm per Newton. Models were developed to optimize the magnet geometry for a specific sensor standoff distance and for particular corrosion pit depths. The sensor was able to detect corrosion pits on a fuel storage tank bottom with depths in the sub-millimeter range. PMID:23995095

  18. Determination of Quantum Chemistry Based Force Fields for Molecular Dynamics Simulations of Aromatic Polymers

    NASA Technical Reports Server (NTRS)

    Jaffe, Richard; Langhoff, Stephen R. (Technical Monitor)

    1995-01-01

    Ab initio quantum chemistry calculations for model molecules can be used to parameterize force fields for molecular dynamics simulations of polymers. Emphasis in our research group is on using quantum chemistry-based force fields for molecular dynamics simulations of organic polymers in the melt and glassy states, but the methodology is applicable to simulations of small molecules, multicomponent systems and solutions. Special attention is paid to deriving reliable descriptions of the non-bonded and electrostatic interactions. Several procedures have been developed for deriving and calibrating these parameters. Our force fields for aromatic polyimide simulations will be described. In this application, the intermolecular interactions are the critical factor in determining many properties of the polymer (including its color).

  19. Force control of a magnetorheological damper using an elementary hysteresis model-based feedforward neural network

    NASA Astrophysics Data System (ADS)

    Ekkachai, Kittipong; Tungpimolrut, Kanokvate; Nilkhamhang, Itthisek

    2013-11-01

    An inverse controller is proposed for a magnetorheological (MR) damper that consists of a hysteresis model and a voltage controller. The force characteristics of the MR damper caused by excitation signals are represented by a feedforward neural network (FNN) with an elementary hysteresis model (EHM). The voltage controller is constructed using another FNN to calculate a suitable input signal that will allow the MR damper to produce the desired damping force. The performance of the proposed EHM-based FNN controller is experimentally compared to existing control methodologies, such as clipped-optimal control, signum function control, conventional FNN, and recurrent neural network with displacement or velocity inputs. The results show that the proposed controller, which does not require force feedback to implement, provides excellent accuracy, fast response time, and lower energy consumption.

  20. Invited Article: VEDA: A web-based virtual environment for dynamic atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Melcher, John; Hu, Shuiqing; Raman, Arvind

    2008-06-01

    We describe here the theory and applications of virtual environment dynamic atomic force microscopy (VEDA), a suite of state-of-the-art simulation tools deployed on nanoHUB (www.nanohub.org) for the accurate simulation of tip motion in dynamic atomic force microscopy (dAFM) over organic and inorganic samples. VEDA takes advantage of nanoHUB's cyberinfrastructure to run high-fidelity dAFM tip dynamics computations on local clusters and the teragrid. Consequently, these tools are freely accessible and the dAFM simulations are run using standard web-based browsers without requiring additional software. A wide range of issues in dAFM ranging from optimal probe choice, probe stability, and tip-sample interaction forces, power dissipation, to material property extraction and scanning dynamics over hetereogeneous samples can be addressed.

  1. Viscoelastic model based force control for soft tissue interaction and its application in physiological motion compensation.

    PubMed

    Moreira, Pedro; Zemiti, Nabil; Liu, Chao; Poignet, Philippe

    2014-09-01

    Controlling the interaction between robots and living soft tissues has become an important issue as the number of robotic systems inside the operating room increases. Many researches have been done on force control to help surgeons during medical procedures, such as physiological motion compensation and tele-operation systems with haptic feedback. In order to increase the performance of such controllers, this work presents a novel force control scheme using Active Observer (AOB) based on a viscoelastic interaction model. The control scheme has shown to be stable through theoretical analysis and its performance was evaluated by in vitro experiments. In order to evaluate how the force control scheme behaves under the presence of physiological motion, experiments considering breathing and beating heart disturbances are presented. The proposed control scheme presented a stable behavior in both static and moving environment. The viscoelastic AOB presented a compensation ratio of 87% for the breathing motion and 79% for the beating heart motion. PMID:24612709

  2. All-Atom Polarizable Force Field for DNA Based on the Classical Drude Oscillator Model

    PubMed Central

    Savelyev, Alexey; MacKerell, Alexander D.

    2014-01-01

    Presented is a first generation atomistic force field for DNA in which electronic polarization is modeled based on the classical Drude oscillator formalism. The DNA model is based on parameters for small molecules representative of nucleic acids, including alkanes, ethers, dimethylphosphate, and the nucleic acid bases and empirical adjustment of key dihedral parameters associated with the phosphodiester backbone, glycosidic linkages and sugar moiety of DNA. Our optimization strategy is based on achieving a compromise between satisfying the properties of the underlying model compounds in the gas phase targeting QM data and reproducing a number of experimental properties of DNA duplexes in the condensed phase. The resulting Drude force field yields stable DNA duplexes on the 100 ns time scale and satisfactorily reproduces (1) the equilibrium between A and B forms of DNA and (2) transitions between the BI and BII sub-states of B form DNA. Consistency with the gas phase QM data for the model compounds is significantly better for the Drude model as compared to the CHARMM36 additive force field, which is suggested to be due to the improved response of the model to changes in the environment associated with the explicit inclusion of polarizability. Analysis of dipole moments associated with the nucleic acid bases shows the Drude model to have significantly larger values than those present in CHARMM36, with the dipoles of individual bases undergoing significant variations during the MD simulations. Additionally, the dipole moment of water was observed to be perturbed in the grooves of DNA. PMID:24752978

  3. Development of AMOEBA force field for 1,3-dimethylimidazolium based ionic liquids.

    PubMed

    Starovoytov, Oleg N; Torabifard, Hedieh; Cisneros, G Andrés

    2014-06-26

    The development of AMOEBA (a multipolar polarizable force field) for imidazolium based ionic liquids is presented. Our parametrization method follows the AMOEBA procedure and introduces the use of QM intermolecular total interactions as well as QM energy decomposition analysis (EDA) to fit individual interaction energy components. The distributed multipoles for the cation and anions have been derived using both the Gaussian distributed multipole analysis (GDMA) and Gaussian electrostatic model-distributed multipole (GEM-DM) methods.1 The intermolecular interactions of a 1,3-dimethylimidazolium [dmim(+)] cation with various anions, including fluoride [F(-)], chloride [Cl(-)], nitrate [NO(3)(-)], and tetraflorouborate [BF(4)(-)], were studied using quantum chemistry calculations at the MP2/6-311G(d,p) level of theory. Energy decomposition analysis was performed for each pair using the restricted variational space decomposition approach (RVS) at the HF/6-311G(d,p) level. The new force field was validated by running a series of molecular dynamic (MD) simulations and by analyzing thermodynamic and structural properties of these systems. A number of thermodynamic properties obtained from MD simulations were compared with available experimental data. The ionic liquid structure reproduced using the AMOEBA force field is also compared with the data from neutron diffraction experiment and other MD simulations. Employing GEM-DM force fields resulted in a good agreement on liquid densities ρ, enthalpies of vaporization ΔH(vap), and diffusion coefficients D(±) in comparison with conventional force fields. PMID:24901255

  4. [Comparison of cell elasticity analysis methods based on atomic force microscopy indentation].

    PubMed

    Wang, Zhe; Hao, Fengtao; Chen, Xiaohu; Yang, Zhouqi; Ding, Chong; Shang, Peng

    2014-10-01

    In order to investigate in greater detail the two methods based on Hertz model for analyzing force-distance curve obtained by atomic force microscopy, we acquired the force-distance curves of Hela and MCF-7 cells by atomic force microscopy (AFM) indentation in this study. After the determination of contact point, Young's modulus in different indentation depth were calculated with two analysis methods of "two point" and "slope fitting". The results showed that the Young's modulus of Hela cell was higher than that of MCF-7 cell,which is in accordance with the F-actin distribution of the two types of cell. We found that the Young's modulus of the cells was decreased with increasing indentation depth and the curve trends by "slope fitting". This indicated that the "slope fitting" method could reduce the error caused by the miscalculation of contact point. The purpose of this study was to provide a guidance for researcher to choose an appropriate method for analyzing AFM indentation force-distance curve. PMID:25764725

  5. 5. Credit USAF, ca. 1944. Original housed in the Muroc ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. Credit USAF, ca. 1944. Original housed in the Muroc Flight Test Base, Unit History, 1 September 1942 - 30 June 1945. Alfred F. Simpson Historical Research Agency. United States Air Force. Maxwell AFB, Alabama. Interior view of hangar, looking north northwest. Note exposed wooden construction. Two jet engines lie partially concealed by tarpaulins in the background, along with a combustion chamber assembly (horizontal cylinders in a circular array). On the workbench in the foreground lie an engine rotor hub and what appears to be an engine fuel line assembly. - Edwards Air Force Base, North Base, Hangar No. 1, First & B Streets, Boron, Kern County, CA

  6. Credit USAF, ca. 1943. Original housed in the Muroc Flight ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Credit USAF, ca. 1943. Original housed in the Muroc Flight Test Base, Unit History, 1 September 1942 - 30 June 1945. Alfred F. Simpson Historical Research Agency. United States Air Force. Maxwell AFB, Alabama. Historic view looking northeast along southeast edge of swimming pool during construction. The wavy edge of the pool visible here remains as a ground surface feature in 1995. Building in the background is the second Bachelor Officers' Quarters (T-15) built in 1943 - Edwards Air Force Base, North Base, Swimming Pool, Second Street, Boron, Kern County, CA

  7. 78 FR 27126 - East Bay, St. Andrews Bay and the Gulf of Mexico at Tyndall Air Force Base, Florida; Restricted...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-09

    ... WGS84 datum for its imagery base and imagery dated January 1, 2012. (2) The areas described in... at Tyndall Air Force Base, Florida; Restricted Areas AGENCY: U.S. Army Corps of Engineers, DoD... establishing six new restricted areas along the Tyndall Air Force Base (AFB) facility shoreline. Tyndall AFB...

  8. Force spectroscopy 101: how to design, perform, and analyze an AFM-based single molecule force spectroscopy experiment.

    PubMed

    Noy, Aleksandr

    2011-10-01

    Single molecule force spectroscopy presents a deceptively simple approach to probing interaction between molecules and molecular assemblies on the nanoscale by measuring forces that it takes to pull the molecules apart. Yet, a more detailed analysis reveals a wealth of different behaviors and interesting physics. This article aims to explore basic physical concepts behind these experiments from a strictly practical point of using these data to extract meaningful information about the interactions. It also focuses on different loading regimes in these experiments, different kinetics that they cause, and different data interpretation that is required for measurements in those regimes. PMID:21862386

  9. Morphological and biochemical analysis by atomic force microscopy and scanning near-field optical microscopy techniques of human keratinocytes (HaCaT) exposed to extremely low frequency 50 Hz magnetic field

    NASA Astrophysics Data System (ADS)

    Rieti, Sabrina; Manni, Vanessa; Lisi, Antonella; Grimaldi, Settimio; Generosi, Renato; Luce, Marco; Perfetti, Paolo; Cricenti, Antonio; Pozzi, Deleana; Giuliani, Livio

    2002-10-01

    We studied the effect of the interaction of electromagnetic radiation with human keratinocytes (HaCaT), at low (50 Hz, 1 mT) frequency using both atomic force microscopy (AFM) and scanning near-field optical microscopy (SNOM) techniques. AFM analysis showed modifications in shape and morphology in exposed cells, while SNOM indirect immunofluorescence analysis revealed an increase of segregation of β4 integrin (an adhesion marker) in the cell membrane of the same cells, suggesting that a higher percentage of the exposed cells shows a modified pattern of this adhesion marker.

  10. Red-shifted aequorin-based bioluminescent reporters for in vivo imaging of Ca2 signaling.

    PubMed

    Curie, Thomas; Rogers, Kelly L; Colasante, Cesare; Brûlet, Philippe

    2007-01-01

    Real-time visualization of calcium (Ca(2+)) dynamics in the whole animal will enable important advances in understanding the complexities of cellular function. The genetically encoded bioluminescent Ca(2+) reporter green fluorescent protein-aequorin (GA) allows noninvasive detection of intracellular Ca(2+) signaling in freely moving mice. However, the emission spectrum of GA is not optimal for detection of activity from deep tissues in the whole animal. To overcome this limitation, two new reporter genes were constructed by fusing the yellow fluorescent protein (Venus) and the monomeric red fluorescent protein (mRFP1) to aequorin. Transfer of aequorin chemiluminescence energy to Venus (VA) is highly efficient and produces a 58 nm red shift in the peak emission spectrum of aequorin. This substantially improves photon transmission through tissue, such as the skin and thoracic cage. Although the Ca(2+)-induced bioluminescence spectrum of mRFP1-aequorin (RA) is similar to that of aequorin, there is also a small peak above 600 nm corresponding to the peak emission of mRFP1. Small amounts of energy transfer between aequorin and mRFP1 yield an emission spectrum with the highest percentage of total light above 600 nm compared with GA and VA. Accordingly, RA is also detected with higher sensitivity from brain areas. VA and RA will therefore improve optical access to Ca(2+) signaling events in deeper tissues, such as the heart and brain, and offer insight for engineering new hybrid molecules. PMID:17311763

  11. Determination of nitric oxide mediating intracellular Ca2+ release on neurons based on confocal microscopy imaging

    NASA Astrophysics Data System (ADS)

    Zheng, Liqin; Wang, Yuhua; He, Yipeng; Zeng, Yixiu; Zhang, Yanding; Xie, Shusen

    2014-09-01

    The gas NO is a ubiquitous intercellular messenger that modulates a wide range of physiological and pathophysiological functions. But few studies were made to study the role of NO in the Ca2+ release in dorsal root ganglion (DRG) neurons by confocal microscopy. Thus the objective of this study was to assess if NO has a role in Ca2+ signaling in DRG neurons using confocal microscopy combined with special fluorescence probe Fluo-3/AM. A 100 μM concentration of the NO donors (Sodium Nitroprusside, Dihydrate, SNP) and NO synthase inhibitor (NG-Monomethyl-L-arginine, Monoacetate salt, L-NMMA) was used in the study. Results showed that the fluorescence intensity increased rapidly after injecting SNP, which indicated that SNP could enhance intracellular Ca2+ release. And the fluorescence intensity shrank gradually with time and kept at a low level for quite a long period after loading with L-NMMA which indicated that L-NMMA could block intracellular Ca2+ release. All these results demonstrated that NO was involved in the regulation of intracellular Ca2+ release in the DRG neurons.

  12. FRET-Based Nanobiosensors for Imaging Intracellular Ca²⁺ and H⁺ Microdomains.

    PubMed

    Zamaleeva, Alsu I; Despras, Guillaume; Luccardini, Camilla; Collot, Mayeul; de Waard, Michel; Oheim, Martin; Mallet, Jean-Maurice; Feltz, Anne

    2015-01-01

    Semiconductor nanocrystals (NCs) or quantum dots (QDs) are luminous point emitters increasingly being used to tag and track biomolecules in biological/biomedical imaging. However, their intracellular use as highlighters of single-molecule localization and nanobiosensors reporting ion microdomains changes has remained a major challenge. Here, we report the design, generation and validation of FRET-based nanobiosensors for detection of intracellular Ca(2+) and H⁺ transients. Our sensors combine a commercially available CANdot(®)565QD as an energy donor with, as an acceptor, our custom-synthesized red-emitting Ca(2+) or H⁺ probes. These 'Rubies' are based on an extended rhodamine as a fluorophore and a phenol or BAPTA (1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetra-acetic acid) for H⁺ or Ca(2+) sensing, respectively, and additionally bear a linker arm for conjugation. QDs were stably functionalized using the same SH/maleimide crosslink chemistry for all desired reactants. Mixing ion sensor and cell-penetrating peptides (that facilitate cytoplasmic delivery) at the desired stoichiometric ratio produced controlled multi-conjugated assemblies. Multiple acceptors on the same central donor allow up-concentrating the ion sensor on the QD surface to concentrations higher than those that could be achieved in free solution, increasing FRET efficiency and improving the signal. We validate these nanosensors for the detection of intracellular Ca(2+) and pH transients using live-cell fluorescence imaging. PMID:26404317

  13. Robust Operation of Tendon-Driven Robot Fingers Using Force and Position-Based Control Laws

    NASA Technical Reports Server (NTRS)

    Abdallah, Muhammad E (Inventor); Platt, Jr., Robert J. (Inventor); Reiland, Matthew J (Inventor); Hargrave, Brian (Inventor); Diftler, Myron A (Inventor); Strawser, Philip A (Inventor); Ihrke, Chris A. (Inventor)

    2013-01-01

    A robotic system includes a tendon-driven finger and a control system. The system controls the finger via a force-based control law when a tension sensor is available, and via a position-based control law when a sensor is not available. Multiple tendons may each have a corresponding sensor. The system selectively injects a compliance value into the position-based control law when only some sensors are available. A control system includes a host machine and a non-transitory computer-readable medium having a control process, which is executed by the host machine to control the finger via the force- or position-based control law. A method for controlling the finger includes determining the availability of a tension sensor(s), and selectively controlling the finger, using the control system, via the force or position-based control law. The position control law allows the control system to resist disturbances while nominally maintaining the initial state of internal tendon tensions.

  14. Infrared Radiative Forcing and Atmospheric Lifetimes of Trace Species Based on Observations from UARS

    NASA Technical Reports Server (NTRS)

    Minschwaner, K.; Carver, R. W.; Briegleb, B. P.

    1997-01-01

    Observations from instruments on the Upper Atmosphere Research Satellite (UARS) have been used to constrain calculations of infrared radiative forcing by CH4, CCl2F2 and N2O, and to determine lifetimes Of CCl2F2 and N2O- Radiative forcing is calculated as a change in net infrared flux at the tropopause that results from an increase in trace gas amount from pre-industrial (1750) to contemporary (1992) times. Latitudinal and seasonal variations are considered explicitly, using distributions of trace gases and temperature in the stratosphere from UARS measurements and seasonally averaged cloud statistics from the International Satellite Cloud Climatology Project. Top-of-atmosphere fluxes calculated for the contemporary period are in good agreement with satellite measurements from the Earth Radiation Budget Experiment. Globally averaged values of the radiative forcing are 0.536, 0.125, and 0.108 W m-2 for CH4, CCl2F2, and N2O, respectively. The largest forcing occurs near subtropical latitudes during summer, predominantly as a result of the combination of cloud-free skies and a high, cold tropopause. Clouds are found to play a significant role in regulating infrared forcing, reducing the magnitude of the forcing by 30-40% compared to the case of clear skies. The vertical profile of CCl2F2 is important in determining its radiative forcing; use of a height-independent mixing ratio in the stratosphere leads to an over prediction of the forcing by 10%. The impact of stratospheric profiles on radiative forcing by CH4 and N2O is less than 2%. UARS-based distributions of CCl2F2 and N2O are used also to determine global destruction rates and instantaneous lifetimes of these gases. Rates of photolytic destruction in the stratosphere are calculated using solar ultraviolet irradiances measured on UARS and a line-by-line model of absorption in the oxygen Schumann-Runge bands. Lifetimes are 114 +/- 22 and 118 +/- 25 years for CCl2F2 and N2O, respectively.

  15. Rehabilitation of the Rocket Vehicle Integration Test Stand at Edwards Air Force Base

    NASA Technical Reports Server (NTRS)

    Jones, Daniel S.; Ray, Ronald J.; Phillips, Paul

    2005-01-01

    Since initial use in 1958 for the X-15 rocket-powered research airplane, the Rocket Engine Test Facility has proven essential for testing and servicing rocket-powered vehicles at Edwards Air Force Base. For almost two decades, several successful flight-test programs utilized the capability of this facility. The Department of Defense has recently demonstrated a renewed interest in propulsion technology development with the establishment of the National Aerospace Initiative. More recently, the National Aeronautics and Space Administration is undergoing a transformation to realign the organization, focusing on the Vision for Space Exploration. These initiatives provide a clear indication that a very capable ground-test stand at Edwards Air Force Base will be beneficial to support the testing of future access-to-space vehicles. To meet the demand of full integration testing of rocket-powered vehicles, the NASA Dryden Flight Research Center, the Air Force Flight Test Center, and the Air Force Research Laboratory have combined their resources in an effort to restore and upgrade the original X-15 Rocket Engine Test Facility to become the new Rocket Vehicle Integration Test Stand. This report describes the history of the X-15 Rocket Engine Test Facility, discusses the current status of the facility, and summarizes recent efforts to rehabilitate the facility to support potential access-to-space flight-test programs. A summary of the capabilities of the facility is presented and other important issues are discussed.

  16. Highly sensitive force sensor based on optical microfiber asymmetrical Fabry-Perot interferometer.

    PubMed

    Gong, Yuan; Yu, Cai-Bin; Wang, Ting-Ting; Liu, Xiu-Ping; Wu, Yu; Rao, Yun-Jiang; Zhang, Ming-Lei; Wu, Hui-Juan; Chen, Xiao-Xiao; Peng, Gang-Ding

    2014-02-10

    An asymmetrical Fabry-Perot interferometric (AFPI) force sensor is fabricated based on a narrowband reflection of low-reflectivity fiber Bragg grating (LR-FBG) and a broadband Fresnel reflection of the cleaved fiber end. The AFPI sensor includes a section of microfiber made by tapering and it achieves a force sensitivity of 0.221 pm/μN with a tapered microfiber of 40 mm length and 6.1 μm waist diameter. Compared with similar AFPI structure in 125 μm-diameter single mode fiber, the force sensitivity of the microfiber AFPI structure is greatly enhanced due to its smaller diameter and can be optimized for different force scales by controlling the diameter. The fabrication process of the AFPI sensor is simple and cost-effective. The AFPI sensor has better multiplexing capacity than conventional extrinsic fiber-optic Fabry-Perot sensors, while it also release the requirement on the wavelength matching of the FBG-pair-based FPI. PMID:24663648

  17. Towards a Mechanism-Based Understanding of Vital Effects: Biomolecules Influence Mg/Ca in Calcite

    NASA Astrophysics Data System (ADS)

    Stephenson, A. E.; Nelson, E. J.; Wu, K. J.; de Yoreo, J. J.; Dove, P. M.

    2006-12-01

    Recent findings from our group suggest that the chemistry of biomolecules present at sites of mineral formation have a strong influence on the structure of water near calcite surfaces (Elhadj et al., CGD, 2006) and exercise predictable controls on the rate of calcite growth (Elhadj et al., submitted). Observing the extent to which biomolecules can mediate growth processes leads us to hypothesize that they also have measurable influence over impurity (Mg, Sr) contents. If true, this could be a significant contributor to the widely documented 'vital effects' that complicate interpretations of paleoenvironments, largely based on chemical signatures found in the skeletal remains of organisms. We use in situ AFM to measure the growth rate of calcite at the nanoscale under controlled solution compositions and at characterized chemical driving force. The relationship between the presence of carboxyl- rich peptides in solution during growth and the magnesium content in the resulting calcite was quantified using time-of-flight SIMS. This new work with tof-SIMS has validated previous compositional maps of Mg distributions collected by electron microprobe, and has yielded new insights into controls on impurity content. We are using similar methods to also determine factors that influence impurity contents of calcites grown in solutions at seawater ionic strength.

  18. Exploring the impact of forcing error characteristics on physically based snow simulations within a global sensitivity analysis framework

    NASA Astrophysics Data System (ADS)

    Raleigh, M. S.; Lundquist, J. D.; Clark, M. P.

    2014-12-01

    Physically based models provide insights into key hydrologic processes, but are associated with uncertainties due to deficiencies in forcing data, model parameters, and model structure. Forcing uncertainty is enhanced in snow-affected catchments, where weather stations are scarce and prone to measurement errors, and meteorological variables exhibit high variability. Hence, there is limited understanding of how forcing error characteristics affect simulations of cold region hydrology. Here we employ global sensitivity analysis to explore how different error types (i.e., bias, random errors), different error distributions, and different error magnitudes influence physically based simulations of four snow variables (snow water equivalent, ablation rates, snow disappearance, and sublimation). We use Sobol' global sensitivity analysis, which is typically used for model parameters, but adapted here for testing model sensitivity to co-existing errors in all forcings. We quantify the Utah Energy Balance model's sensitivity to forcing errors with 1 520 000 Monte Carlo simulations across four sites and four different scenarios. Model outputs were generally (1) more sensitive to forcing biases than random errors, (2) less sensitive to forcing error distributions, and (3) sensitive to different forcings depending on the relative magnitude of errors. For typical error magnitudes, precipitation bias was the most important factor for snow water equivalent, ablation rates, and snow disappearance timing, but other forcings had a significant impact depending on forcing error magnitudes. Additionally, the relative importance of forcing errors depended on the model output of interest. Sensitivity analysis can reveal which forcing error characteristics matter most for hydrologic modeling.

  19. LandCaRe-DSS - model based tools for irrigation management under climate change

    NASA Astrophysics Data System (ADS)

    Dotterweich, Markus; Wilkinson, Kristina; Cassel, Martin; Scherzer, Jörg; Köstner, Barbara; Berg, Michael; Grocholl, Jürgen

    2015-04-01

    Climate change is expected to have a strong influence on agricultural systems in the future. It will be important for decision makers and stakeholders to assess the impact of climate change at the farm and regional level in order to facilitate and maintain a sustainable and profitable farming infrastructure. Climate change impact studies have to incorporate aspects of uncertainty and the underlying knowledge is constantly expanding and improving. Decision support systems (DSS) with flexible data bases are therefore a useful tool for management and planning: different models can be applied under varying boundary conditions within a conceptual framework and the results can be used e.g. to show the effects of climate change scenarios and different land management options. Within this project, the already existing LandCaRe DSS will be further enhanced and improved. A first prototype had been developed for two regions in eastern Germany, mainly to show the effects of climate change on yields, nutrient balances and farm economy. The new model version will be tested and applied for a region in north-western Germany (Landkreis Uelzen) where arable land makes up about 50% of overall land-use and where 80 % of the arable land is already irrigated. For local decision makers, it will be important to know how water demand and water availability are likely to change in the future: Is more water needed for irrigation? Is more water actually available for irrigation? Will the existing limits for ground water withdrawal be sufficient for farmers to irrigate their crops? How can the irrigation water demand be influenced by land management options like the use of different crops and varieties or different farming and irrigation techniques? The main tasks of the project are (I) the integration of an improved irrigation model, (II) the development of a standardized interface to apply the DSS in different regions, (III) to optimize the graphical user interface, (IV) to transfer and

  20. Analysis of Snow Albedo, Grain Size and Radiative Forcing based on the Airborne Snow Observatory (ASO) Imaging Spectroscopy Data

    NASA Astrophysics Data System (ADS)

    Seidel, F. C.; Painter, T. H.

    2013-12-01

    Climate is expected to be most vulnerable in mountainous and arctic regions where the atmosphere and the hydrosphere are directly linked to the cryosphere. A combination of modeling and large-scale observational efforts is required to investigate related scientific questions. NASA's Airborne Snow Observatory (ASO) at the Jet Propulsion Laboratory addresses some of these needs by establishing new quantitative observational capabilities in regional mapping of mountain snow properties. In addition, ASO's key products showed that we are able to achieve societal benefits by improving water resources management. We will show the first analysis of snow optical products (albedo, grain size, and radiative forcing) from the spring 2013 ASO campaign in the Sierra Nevada, CA, USA. In addition, we will present the retrieval methods used to derive these products based on airborne imaging spectroscopy, LiDAR, as well as radiative transfer models. The preliminary findings provide new important insights into the temporal and spatial aspects of Western US mountain snow and its melt.

  1. Vehicle Dynamics Control of In-wheel Electric Motor Drive Vehicles Based on Averaging of Tire Force Usage

    NASA Astrophysics Data System (ADS)

    Masaki, Nobuo; Iwano, Haruo; Kamada, Takayoshi; Nagai, Masao

    For in-wheel electric motor drive vehicles, a new vehicle dynamics control which is based on the tire force usage rate is proposed. The new controller adopts non-linear optimal control could manage the interference between direct yaw-moment control and the tire force usage rate. The new control is considered total longitudinal and transverse tire force. Therefore the controller can prevent tire force saturation near tire force limit during cornering. Simulations and test runs by the custom made four wheel drive in-wheel motor electric vehicle show that higher driving stability performance compared to the performance of the same vehicle without control.

  2. Microscopic evidence for Ca(2+) mediated pectin-pectin interactions in carrot-based suspensions.

    PubMed

    Kyomugasho, Clare; Willemsen, Katleen L D D; Christiaens, Stefanie; Van Loey, Ann M; Hendrickx, Marc E

    2015-12-01

    This study explored the use of fluorescently labeled pectin to obtain evidence for Ca(2+) mediated pectin-pectin interactions in situ. Specifically, carrots were either blanched at low temperature (LTB) or blanched at high temperature (HTB) to activate or inactivate endogenous pectin methylesterase, respectively. Consequently, pectin in tissue particles of LTB and HTB carrots exhibited low degree of methylesterification (DM) and high DM, respectively. Pectin present in the LTB carrot serum exhibited a lower DM, was more branched, and showed a higher molar mass compared to HTB carrot serum pectin. Ca(2+) mediated pectin-pectin interactions were influenced by serum pectin molecular structure, increased with increasing pH and Ca(2+) concentration, and decreasing DM. Presence of more linear pectin in the serum created a competition, leading to less intense interactions between labeled pectin and pectin at tissue particle surfaces. Generally, the most intense Ca(2+) mediated pectin-pectin interactions were observed for pectin of LTB carrot particles. PMID:26041174

  3. Montreal Cognitive Assessment (MoCA)-Italian version: regression based norms and equivalent scores.

    PubMed

    Conti, Silvia; Bonazzi, Stefano; Laiacona, Marcella; Masina, Marco; Coralli, Mirco Vanelli

    2015-02-01

    The Montreal Cognitive Assessment (MoCA) is a brief cognitive screening instrument developed by Nasreddine et al. to detect mild cognitive impairment, a high-risk condition for Alzheimer's disease and other forms of dementia. In this study we report normative data on the MoCA-Italian version, collected on a sample of 225 Italian healthy subjects ranged in age between 60 and 80 years, and in formal education from 5 to 23 years. The global normal cognition was established in accordance with the Mini-Mental State Examination score and with the Prose Memory Test score (Spinnler and Tognoni, Ital J Neurol Sci 6:25-27, 1987). None of the participants had a history of psychiatric, neurological, cerebrovascular disorders or brain injury or took drugs affecting cognition. Linear regression analysis was performed to evaluate the potential effect of age, education and sex on the MoCA total performance score. We provide correction grids to adjust raw scores and equivalent scores with cut-off value to allow comparison between MoCA performance and others neuropsychological test scores that can be administered on the same subject. PMID:25139107

  4. Baseline meteorological soundings for parametric environmental investigations at Kennedy Space Center and Vandenberg Air Force Base

    NASA Technical Reports Server (NTRS)

    Susko, M.; Stephens, J. B.

    1976-01-01

    Meteorological soundings representative of the atmospheric environment at the Kennedy Space Center, Florida and Vandenberg Air Force Base, California, are presented. Synthetic meteorological soundings at Kennedy Space Center, including fall, spring, and a sea breeze, and at Vandenberg Air Force Base (sea breeze with low and high level inversion and stationary upper level troughs) are shown. Soundings of frontal passages are listed. The Titan launch soundings at Kennedy Space Center present a wide range of meteorological conditions, both seasonal and time of day variations. The meteorological data input of altitude, wind speed, wind direction, temperature, and pressure may be used as meteorological inputs for the NASA/MSFC Multilayer Diffusion Model or other models to obtain quantitative estimates of effluent concentrations associated with the potential emission of major combustion products in the lower atmosphere to simulate actual launches of space vehicles. The Titan launch soundings are also of value in terms of rocket effluent measurements for analysis purposes.

  5. Polarizable Empirical Force Field for Hexopyranose Monosaccharides Based on the Classical Drude Oscillator

    PubMed Central

    2015-01-01

    A polarizable empirical force field based on the classical Drude oscillator is presented for the hexopyranose form of selected monosaccharides. Parameter optimization targeted quantum mechanical (QM) dipole moments, solute–water interaction energies, vibrational frequencies, and conformational energies. Validation of the model was based on experimental data on crystals, densities of aqueous-sugar solutions, diffusion constants of glucose, and rotational preferences of the exocylic hydroxymethyl of d-glucose and d-galactose in aqueous solution as well as additional QM data. Notably, the final model involves a single electrostatic model for all sixteen diastereomers of the monosaccharides, indicating the transferability of the polarizable model. The presented parameters are anticipated to lay the foundation for a comprehensive polarizable force field for saccharides that will be compatible with the polarizable Drude parameters for lipids and proteins, allowing for simulations of glycolipids and glycoproteins. PMID:24564643

  6. Immediate-early gene transcriptional activation in hippocampus CA1 and CA3 does not accurately reflect rapid, pattern completion-based retrieval of context memory

    PubMed Central

    Pevzner, Aleksandr

    2015-01-01

    No studies to date have examined whether immediate-early gene (IEG) activation is driven by context memory recall. To address this question, we utilized the context preexposure facilitation effect (CPFE) paradigm. In CPFE, animals acquire contextual fear conditioning through hippocampus-dependent rapid retrieval of a previously formed contextual representation. Despite differences in behavior, we did not find any difference in CA1 or CA3 IEG activity associated with this rapid recall phase when comparing context preexposed and non-pre-exposed groups. These findings indicate that IEG activation in CA1 and CA3 is not an accurate readout of the neural activity associated with hippocampus-dependent rapid memory retrieval. PMID:25512571

  7. 19. DETAIL OF AIR FORCE WEATHER INFORMATION TERMINAL AND CHART ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. DETAIL OF AIR FORCE WEATHER INFORMATION TERMINAL AND CHART RECORDER LOCATED IMMEDIATELY NORTH OF CONSOLE IN PHOTOS A-15 THROUGH A-18. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Operations Building, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  8. Exploration and Resource Assessment at Mountain Home Air Force Base, Idaho Using an Integrated Team Approach

    SciTech Connect

    Joseph C. Armstrong; Robert P. Breckenridge; Dennis L. Nielson; John W. Shervais; Thomas R. Wood

    2012-10-01

    The U.S. Air Force is facing a number of challenges as it moves into the future, one of the biggest being how to provide safe and secure energy to support base operations. A team of scientists and engineers met at Mountain Home Air Force Base near Boise, Idaho, to discuss the possibility of exploring for geothermal resources under the base. The team identified that there was a reasonable potential for geothermal resources based on data from an existing well. In addition, a regional gravity map helped identify several possible locations for drilling a new well. The team identified several possible sources of funding for this well—the most logical being to use U.S. Department of Energy funds to drill the upper half of the well and U.S. Air Force funds to drill the bottom half of the well. The well was designed as a slimhole well in accordance with State of Idaho Department of Water Resources rules and regulations. Drilling operations commenced at the Mountain Home site in July of 2011 and were completed in January of 2012. Temperatures increased gradually, especially below a depth of 2000 ft. Temperatures increased more rapidly below a depth of 5500 ft. The bottom of the well is at 5976 ft, where a temperature of about 140°C was recorded. The well flowed artesian from a depth below 5600 ft, until it was plugged off with drilling mud. Core samples were collected from the well and are being analyzed to help understand permeability at depth. Additional tests using a televiewer system will be run to evaluate orientation and directions at fractures, especially in the production zone. A final report on the well exploitation will be forthcoming later this year. The Air Force will use it to evaluate the geothermal resource potential for future private development options at Mountain Home AFB.

  9. Perspective Primary Teachers Explores Magnetic Interactions As A Base To Understand Lorentz Force

    NASA Astrophysics Data System (ADS)

    Michelini, Marisa; Viola, Rossana

    2008-05-01

    Lorentz's Force represents a conceptual gap as for the analysis of the simple effects related to the properties characterizing the electric and magnetic nature of phenomena. Searching for the definition of a teaching/learning path according to MRE model [5] a research dedicated to primary school prospective teachers has been carried out. This learning path is structured and based on experimental practice [4] according to PCK guide lines and main results are here presented on the side of teachers training.

  10. STS-30 crew egresses OV-104 via stairway at Edwards Air Force Base (EAFB)

    NASA Technical Reports Server (NTRS)

    1989-01-01

    STS-30 crewmembers egress Atlantis, Orbiter Vehicle (OV) 104, via mobile stairway at Edwards Air Force Base (EAFB), California, ending their four-day mission. From bottom of the stairs to the top are Commander David M. Walker, Pilot Ronald J. Grabe, Mission Specialist (MS) Norman E. Thagard, MS Mary L. Cleave, and MS Mark C. Lee. OV-104 landed at 12:44:33 pm (Pacific Daylight Time (PDT)) on EAFB concrete runway 22.

  11. STS-27 crew egresses Atlantis, OV-104, at Edwards Air Force Base, California

    NASA Technical Reports Server (NTRS)

    1988-01-01

    During post landing activity, the five astronaut crewmembers for STS-27 egress Atlantis, Orbiter Vehicle (OV) 104, at Edwards Air Force Base (EAFB), California. The astronauts, wearing navy blue flight coveralls (jumpsuits), walk down mobile stairway. From bottom of steps to top, are Commander Robert L. Gibson, Pilot Guy S. Gardner, Mission Specialist (MS) Richard M. Mullane, MS Jerry L. Ross, and MS William M. Shepherd. Ground crews look on in background.

  12. Geothermal exploration program, Hill Air Force Base, Davis and Weber Counties, Utah

    SciTech Connect

    Glenn, W.E.; Chapman, D.S.; Foley, D.; Capuano, R.M.; Cole, D.; Sibbett, B.; Ward, S.H.

    1980-03-01

    Results obtained from a program designed to locate a low- or moderate-temperature geothermal resource that might exist beneath Hill Air Force Base (AFB), Ogden, Utah are discussed. A phased exploration program was conducted at Hill AFB. Published geological, geochemical, and geophysical reports on the area were examined, regional exploration was conducted, and two thermal gradient holes were drilled. This program demonstrated that thermal waters are not present in the shallow subsurface at this site. (MHR)

  13. CaMKII-Based Regulation of Voltage-Gated Na+ Channel in Cardiac Disease

    PubMed Central

    Koval, Olha M.; Snyder, Jedidiah S.; Wolf, Roseanne M.; Pavlovicz, Ryan E.; Glynn, Patric; Curran, Jerry; Leymaster, Nicholas D.; Dun, Wen; Wright, Patrick J.; Cardona, Natalia; Qian, Lan; Mitchell, Colleen C.; Boyden, Penelope A.; Binkley, Philip F.; Li, Chenglong; Anderson, Mark E.; Mohler, Peter J.; Hund, Thomas J.

    2012-01-01

    Background Human gene variants affecting ion channel biophysical activity and/or membrane localization are linked with potentially fatal cardiac arrhythmias. However, the mechanism for many human arrhythmia variants remains undefined despite over a decade of investigation. Post-translational modulation of membrane proteins is essential for normal cardiac function. Importantly, aberrant myocyte signaling has been linked to defects in cardiac ion channel post-translational modifications and disease. We recently identified a novel pathway for post-translational regulation of the primary cardiac voltage-gated Na+ channel (Nav1.5) by CaMKII. However, a role for this pathway in cardiac disease has not been evaluated. Methods and Results We evaluated the role of CaMKII-dependent phosphorylation in human genetic and acquired disease. We report an unexpected link between a short motif in the Nav1.5 DI-DII loop, recently shown to be critical for CaMKII-dependent phosphorylation, and Nav1.5 function in monogenic arrhythmia and common heart disease. Experiments in heterologous cells and primary ventricular cardiomyocytes demonstrate that human arrhythmia susceptibility variants (A572D and Q573E) alter CaMKII-dependent regulation of Nav1.5 resulting in abnormal channel activity and cell excitability. In silico analysis reveals that these variants functionally mimic the phosphorylated channel resulting in increased susceptibility to arrhythmia-triggering afterdepolarizations. Finally, we report that this same motif is aberrantly regulated in a large animal model of acquired heart disease and in failing human myocardium. Conclusions We identify the mechanism for two human arrhythmia variants that affect Nav1.5 channel activity through direct effects on channel post-translational modification. We propose that the CaMKII phosphorylation motif in the Nav1.5 DI-DII cytoplasmic loop is a critical nodal point for pro-arrhythmic changes to Nav1.5 in congenital and acquired cardiac

  14. Development and precision position/force control of a new flexure-based microgripper

    NASA Astrophysics Data System (ADS)

    Yang, Yi-ling; Wei, Yan-ding; Lou, Jun-qiang; Xie, Feng-ran; Fu, Lei

    2016-01-01

    This paper presents the design, modeling and position/force control of a new piezo-driven microgripper with integrated position and force sensors. The structural design of the microgripper is based on double amplification mechanisms employing the bridge-type mechanism and the parallelogram mechanism. The microgripper can generate a large gripping range and pure translation of the gripping arm. Through the pseudorigid-body-model method, theoretical models are derived. By means of several finite-element analysis simulations, the optimal structural parameters for the microgripper are acquired and the theoretical models are analyzed and validated. Furthermore, to improve the performance of the microgripper, a new hybrid position/force control scheme employing a nonlinear fuzzy logic controller combined with an incremental proportional-integral controller is presented. The control scheme is capable of regulating the position and the gripping force of the microgripper simultaneously. Experimental investigation and validation were performed and the experimental results verify the effectiveness of the developed structural design and the proposed hybrid control scheme.

  15. New method of space debris cleaning based on light negative force: tractor laser

    NASA Astrophysics Data System (ADS)

    Sun, Qiongge; Gao, Long; Li, Chen

    2016-01-01

    This paper presents a new way of space debris removal and protection, that is, using tractor laser, which based on light negative force, to achieve space debris cleaning and shielded. Tractor laser is traceable from the theory of optical tweezers, accompanied with non-diffraction beam. These kind of optical beams have the force named negative force pointing to optical source, this will bring the object along the trajectory of laser beam moving to the optical source. The negative force leads to the new method to convey and sampling the space micro-objects. In this paper, the application of tractor laser in the space debris collection and protection of 1cm is studied. The application of the several tractor beams in the space debris and sample collection is discussed. The proposed method can reduce the requirements of the laser to the satellite platform, and realize the collection of space debris, make the establishment of the space garbage station possible, and help to study the spatial non contact sample transmission and reduce the risk of space missions.

  16. A Physically-Based Estimate of Radiative Forcing by Anthropogenic Sulfate Aerosol

    SciTech Connect

    Ghan, Steven J.); Easter, Richard C.); Chapman, Elaine G.); Abdul-Razzak, Hayder; Zhang, Yang ); Leung, Ruby ); Laulainen, Nels S.); Saylor, Rick D.); Zaveri, Rahul A.)

    2001-04-01

    Estimates of direct and indirect radiative forcing by anthropogenic sulfate aerosols from an integrated global aerosol and climate modeling system are presented. A detailed global tropospheric chemistry and aerosol model that predicts concentrations of oxidants as well as aerosols and aerosol precursors, is coupled to a general circulation model that predicts both cloud water mass and cloud droplet number. Both number and mass of several externally-mixed aerosol size modes are predicted, with internal mixing assumed for the different aerosol components within each mode. Predicted aerosol species include sulfate, organic and black carbon, soil dust, and sea salt. The models use physically-based treatments of aerosol radiative properties (including dependence on relative humidity) and aerosol activation as cloud condensation nuclei. Parallel simulations with and without anthropogenic sulfate aerosol are performed for a global domain. The global and annual mean direct and indirect radiative forcing due to anthropogenic sulfate are estimated to be -0.3 to -0.5 and -1.5 to -3.0 W m-2, respectively. The radiative forcing is sensitive to the model's horizontal resolution, the use of predicted vs. analyzed relative humidity, the prediction vs. diagnosis of aerosol number and droplet number, and the parameterization of droplet collision/coalescence. About half of the indirect radiative forcing is due to changes in droplet radius and half to increased cloud liquid water.

  17. A Force-Based, Parallel Assay for the Quantification of Protein-DNA Interactions

    PubMed Central

    Limmer, Katja; Pippig, Diana A.; Aschenbrenner, Daniela; Gaub, Hermann E.

    2014-01-01

    Analysis of transcription factor binding to DNA sequences is of utmost importance to understand the intricate regulatory mechanisms that underlie gene expression. Several techniques exist that quantify DNA-protein affinity, but they are either very time-consuming or suffer from possible misinterpretation due to complicated algorithms or approximations like many high-throughput techniques. We present a more direct method to quantify DNA-protein interaction in a force-based assay. In contrast to single-molecule force spectroscopy, our technique, the Molecular Force Assay (MFA), parallelizes force measurements so that it can test one or multiple proteins against several DNA sequences in a single experiment. The interaction strength is quantified by comparison to the well-defined rupture stability of different DNA duplexes. As a proof-of-principle, we measured the interaction of the zinc finger construct Zif268/NRE against six different DNA constructs. We could show the specificity of our approach and quantify the strength of the protein-DNA interaction. PMID:24586920

  18. 33 CFR 334.746 - U.S. Coast Guard, Destin Station at Eglin Air Force Base, Fla.; restricted area.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... at Eglin Air Force Base, Fla.; restricted area. 334.746 Section 334.746 Navigation and Navigable... REGULATIONS § 334.746 U.S. Coast Guard, Destin Station at Eglin Air Force Base, Fla.; restricted area. (a) The... CFR part 329, within the area bounded by a line connecting the following coordinates: Commencing...

  19. 33 CFR 334.700 - Choctawhatchee Bay, aerial gunnery ranges, Air Armament Center, Eglin Air Force Base, Fla.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... gunnery ranges, Air Armament Center, Eglin Air Force Base, Fla. 334.700 Section 334.700 Navigation and... Air Force Base, Fla. (a) The danger zones—(1) Aerial gunnery range in west part of Choctawhatchee Bay. The danger zone shall encompass all navigable waters of the United States as defined at 33 CFR...

  20. 33 CFR 334.700 - Choctawhatchee Bay, aerial gunnery ranges, Air Armament Center, Eglin Air Force Base, Fla.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... gunnery ranges, Air Armament Center, Eglin Air Force Base, Fla. 334.700 Section 334.700 Navigation and... Air Force Base, Fla. (a) The danger zones—(1) Aerial gunnery range in west part of Choctawhatchee Bay. The danger zone shall encompass all navigable waters of the United States as defined at 33 CFR...

  1. 33 CFR 334.742 - Eglin Camp Pinchot, Fla., at Eglin Air Force Base, Fla.; restricted area.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Eglin Air Force Base, Fla.; restricted area. 334.742 Section 334.742 Navigation and Navigable Waters... REGULATIONS § 334.742 Eglin Camp Pinchot, Fla., at Eglin Air Force Base, Fla.; restricted area. (a) The area. The restricted area shall encompass all navigable waters of the United States, as defined at 33...

  2. 33 CFR 334.746 - U.S. Coast Guard, Destin Station at Eglin Air Force Base, Fla.; restricted area.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... at Eglin Air Force Base, Fla.; restricted area. 334.746 Section 334.746 Navigation and Navigable... REGULATIONS § 334.746 U.S. Coast Guard, Destin Station at Eglin Air Force Base, Fla.; restricted area. (a) The... CFR part 329, within the area bounded by a line connecting the following coordinates: Commencing...

  3. Effect of oxidizer nanostructures on propulsion forces generated by thermal ignition of nano-aluminum-based propellants.

    PubMed

    Ahn, Ji Young; Kim, Ji Hoon; Kim, Jong Man; Lee, Deug Woo; Park, Jong Kweon; Kim, Soo Hyung

    2013-10-01

    We demonstrated that the size and morphology of an oxidizer have strong effects on the propulsion forces of nano-Al-based propellants. Enhanced propulsion forces could be obtained through the creation and addition of various oxidizer nanoparticles and nanowires in nano-Al-based propellants. PMID:24245184

  4. 33 CFR 334.740 - Weekley Bayou, an arm of Boggy Bayou, Fla., at Eglin Air Force Base; restricted area.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Weekley Bayou, an arm of Boggy Bayou, Fla., at Eglin Air Force Base; restricted area. 334.740 Section 334.740 Navigation and Navigable... REGULATIONS § 334.740 Weekley Bayou, an arm of Boggy Bayou, Fla., at Eglin Air Force Base; restricted area....

  5. 33 CFR 334.740 - Weekley Bayou, an arm of Boggy Bayou, Fla., at Eglin Air Force Base; restricted area.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Weekley Bayou, an arm of Boggy Bayou, Fla., at Eglin Air Force Base; restricted area. 334.740 Section 334.740 Navigation and Navigable... REGULATIONS § 334.740 Weekley Bayou, an arm of Boggy Bayou, Fla., at Eglin Air Force Base; restricted area....

  6. Ecological risk assessment for Mather Air Force Base, California: Phase 1, screening assessment

    SciTech Connect

    Meyers-Schoene, L.; Fischer, N.T.; Rabe, J.J.

    1994-12-31

    Mather Air Force Base (AFB) is among the numerous facilities scheduled for closure under the US Air Force (USAF) Installation Restoration Program (IRP). A component of the Mather AFB IRP is to prepare risk assessments for each of the chemically contaminated sites. Because no previous ecological risk related studies have been conducted on Mather AFB, the authors proposed a phased approach to assessing ecological risks at the base. Phase 1 consisted of baseline ecological surveys that collected data over a 12-month period. In addition, benchmark screening criteria were used in conjunction with modeling results that utilized measured concentrations of chemical analytes in abiotic samples. Phase 2 may consist of the collection of more site-specific data and toxicity testing, if warranted by the Phase 1 screening analysis. This approach was in agreement with the USAF`s ecological risk assessment guidance and met the approval of the Air Force and USEPA Region 9. The authors found the use of established and derived screening values to effectively aid in the focusing of the ecological risk assessment on those chemicals most likely to be hazardous to ecological receptors at the base. Disadvantages in the use of screening values include the uncertainties associated with the conservative assumptions inherent in the derivation of benchmark values and the difficulty in extrapolating from laboratory determined benchmark values to impacts in the field.

  7. Estimation of tensile force in tie-rods using a frequency-based identification method

    NASA Astrophysics Data System (ADS)

    Amabili, M.; Carra, S.; Collini, L.; Garziera, R.; Panno, A.

    2010-05-01

    A technique is developed to identify in-situ the tensile force in tie-rods which are used in ancient monumental masonry buildings to eliminate the lateral load exercised by the vaults and arcs. The technique is based on a frequency-based identification method that allows to minimize the measurement error and that is of simple execution. In particular, the first natural frequencies of the tie-rods are experimentally identified by measuring the frequency response functions (FRFs) with instrumented hammer excitation; four to six natural frequencies can be easily identified with a simple test. Then, a numerical model, based on the Rayleigh-Ritz method, is developed for the axially loaded tie-rod by using the Timoshenko beam theory retaining shear deformation and rotary inertia. Non-uniform section of the rod is considered since this is often the case for hand-made tie-rods in old buildings. The part of the tie-rod inserted inside the masonry wall is also modeled and a simple support is assumed at the extremities inside the walls. The constraints given to the part of the tie-rod inserted inside the masonry structure are assumed to be elastic foundations. The tensile force and the stiffness of the foundation are the unknowns. In some cases, the length of the rod inside the masonry wall can be also assumed as unknown. The numerical model is used to calculate the natural frequencies for a given set of unknowns. Then, a weighted difference between the calculated and identified natural frequencies is calculated and this difference is minimized in order to identify the unknowns, and in particular the tensile force. An estimation of the error in the identification of the force is given. The technique has been tested on five tie-rods at the ground floor of the famous castle of Fontanellato, Italy.

  8. MEMS based Low Cost Piezoresistive Microcantilever Force Sensor and Sensor Module

    PubMed Central

    Pandya, H. J.; Kim, Hyun Tae; Roy, Rajarshi; Desai, Jaydev P.

    2014-01-01

    In the present work, we report fabrication and characterization of a low-cost MEMS based piezoresistive micro-force sensor with SU-8 tip using laboratory made silicon-on-insulator (SOI) substrate. To prepare SOI wafer, silicon film (0.8 µm thick) was deposited on an oxidized silicon wafer using RF magnetron sputtering technique. The films were deposited in Argon (Ar) ambient without external substrate heating. The material characteristics of the sputtered deposited silicon film and silicon film annealed at different temperatures (400–1050°C) were studied using atomic force microscopy (AFM) and X-ray diffraction (XRD) techniques. The residual stress of the films was measured as a function of annealing temperature. The stress of the as-deposited films was observed to be compressive and annealing the film above 1050°C resulted in a tensile stress. The stress of the film decreased gradually with increase in annealing temperature. The fabricated cantilevers were 130 µm in length, 40 µm wide and 1.0 µm thick. A series of force-displacement curves were obtained using fabricated microcantilever with commercial AFM setup and the data were analyzed to get the spring constant and the sensitivity of the fabricated microcantilever. The measured spring constant and sensitivity of the sensor was 0.1488N/m and 2.7mV/N. The microcantilever force sensor was integrated with an electronic module that detects the change in resistance of the sensor with respect to the applied force and displays it on the computer screen. PMID:24855449

  9. Fluorescence-Based Force/Tension Sensors: A Novel Tool to Visualize Mechanical Forces in Structural Proteins in Live Cells

    PubMed Central

    Guo, Jun; Sachs, Frederick

    2014-01-01

    Abstract Significance: Three signaling systems, chemical, electrical, and mechanical, ubiquitously contribute to cellular activities. There is limited information on the mechanical signaling system because of a lack of tools to measure stress in specific proteins. Although significant advances in methodologies such as atomic force microscopy and laser tweezers have achieved great success in single molecules and measuring the mean properties of cells and tissues, they cannot deal with specific proteins in live cells. Recent Advances: To remedy the situation, we developed a family of genetically encoded optical force sensors to measure the stress in structural proteins in living cells. The sensors can be incorporated into specific proteins and are not harmful in transgenic animals. The chimeric proteins distribute and function as their wild-type counterparts, and local stress can be read out from changes in Förster resonance energy transfer (FRET). Critical Issues: Our original sensor used two mutant green fluorescence proteins linked by an alpha helix that served as a linking spring. Ever since, we have improved the probe design in a number of ways. For example, we replaced the helical linker with more common elastic protein domains to better match the compliance of the wild-type hosts. We greatly improved sensitivity by using the angular dependence of FRET rather than the distance dependence as the transduction mechanism, because that has nearly 100% efficiency at rest and nearly zero when stretched. Future Directions: These probes enable researchers to investigate the roles of mechanical force in cellular activities at the level of single molecules, cells, tissues, and whole animals. Antioxid. Redox Signal. 20, 986–999. PMID:24205787

  10. (Environmental investigation of ground water contamination at Wright- Patterson Air Force Base, Ohio)

    SciTech Connect

    Not Available

    1991-10-01

    This Health and Safety Plan (HSP) was developed for the Environmental Investigation of Ground-water Contamination Investigation at Wright-Patterson Air Force Base near Dayton, Ohio, based on the projected scope of work for the Phase 1, Task 4 Field Investigation. The HSP describes hazards that may be encountered during the investigation, assesses the hazards, and indicates what type of personal protective equipment is to be used for each task performed. The HSP also addresses the medical monitoring program, decontamination procedures, air monitoring, training, site control, accident prevention, and emergency response.

  11. Physical properties of solar chromospheric plages. III - Models based on Ca II and Mg II observations

    NASA Technical Reports Server (NTRS)

    Kelch, W. L.; Linsky, J. L.

    1978-01-01

    Solar plages are modeled using observations of both the Ca II K and the Mg II h and k lines. A partial-redistribution approach is employed for calculating the line profiles on the basis of a grid of five model chromospheres. The computed integrated emission intensities for the five atmospheric models are compared with observations of six regions on the sun as well as with models of active-chromosphere stars. It is concluded that the basic plage model grid proposed by Shine and Linsky (1974) is still valid when the Mg II lines are included in the analysis and the Ca II and Mg II lines are analyzed using partial-redistribution diagnostics.

  12. Hierarchical CaCO3 chromatography: a stationary phase based on biominerals.

    PubMed

    Sato, Kosuke; Oaki, Yuya; Takahashi, Daisuke; Toshima, Kazunobu; Imai, Hiroaki

    2015-03-23

    In biomineralization, acidic macromolecules play important roles for the growth control of crystals through a specific interaction. Inspired by this interaction, we report on an application of the hierarchical structures in CaCO3 biominerals to a stationary phase of chromatography. The separation and purification of acidic small organic molecules are achieved by thin-layer chromatography and flash chromatography using the powder of biominerals as the stationary phase. The unit nanocrystals and their oriented assembly, the hierarchical structure, are suitable for the adsorption site of the target organic molecules and the flow path of the elution solvents, respectively. The separation mode is ascribed to the specific adsorption of the acidic molecules on the crystal face and the coordination of the functional groups to the calcium ions. The results imply that a new family of stationary phase of chromatography can be developed by the fine tuning of hierarchical structures in CaCO3 materials. PMID:25677568

  13. Design and Flight Evaluation of a New Force-Based Flow Angle Probe

    NASA Technical Reports Server (NTRS)

    Corda, Stephen; Vachon, Michael Jacob

    2006-01-01

    A novel force-based flow angle probe was designed and flight tested on the NASA F-15B Research Testbed aircraft at NASA Dryden Flight Research Center. The prototype flow angle probe is a small, aerodynamic fin that has no moving parts. Forces on the prototype flow angle probe are measured with strain gages and correlated with the local flow angle. The flow angle probe may provide greater simplicity, greater robustness, and better access to flow measurements in confined areas relative to conventional moving vane-type flow angle probes. Flight test data were obtained at subsonic, transonic, and supersonic Mach numbers to a maximum of Mach 1.70. Flight conditions included takeoff, landing, straight and level flight, flight at higher aircraft angles of attack, and flight at elevated g-loadings. Flight test maneuvers included angle-of-attack and angle-of-sideslip sweeps. The flow angle probe-derived flow angles are compared with those obtained with a conventional moving vane probe. The flight tests validated the feasibility of a force-based flow angle measurement system.

  14. Critical Assessment of P2O5 Activity Coefficients in CaO-based Slags during Dephosphorization Process of Iron-based Melts

    NASA Astrophysics Data System (ADS)

    Yang, Xue-min; Li, Jin-yan; Chai, Guo-Ming; Duan, Dong-ping; Zhang, Jian

    2016-05-01

    According to the experimental results of hot metal dephosphorization by CaO-based slags at a commercial-scale hot metal pretreatment station, activity a_{{{{P}}_{ 2} {{O}}_{ 5} }} of P2O5 in the CaO-based slags has been determined using the calculated comprehensive mass action concentration N_{{{{Fe}}t {{O}}}}{} of iron oxides by the ion and molecule coexistence theory (IMCT) for representing the reaction ability of Fe t O, i.e., activity of a_{{{{Fe}}t {{O}}}}{} . The collected ten models from the literature for predicting activity coefficient γ_{{{{P}}_{ 2} {{O}}_{ 5} }} of P2O5 in CaO-based slags have been evaluated based on the determined activity a_{{{{P}}_{ 2} {{O}}_{ 5} }} of P2O5 by the IMCT as the criterion. The collected ten models of activity coefficient γ_{{{{P}}_{ 2} {{O}}_{ 5} }} of P2O5 in CaO-based slags can be described in the form of a linear function as log γ_{{{{P}}_{ 2} {{O}}_{ 5} }} ≡ y = c0 + c1 x , in which independent variable x represents the chemical composition of slags, intercept c0 including the constant term depicts temperature effect and other unmentioned or acquiescent thermodynamic factors, and slope c1 is regressed by the experimental results. Thus, a general approach for obtaining good prediction results of activity a_{{{{P}}_{ 2} {{O}}_{ 5} }} of P2O5 in CaO-based slags is proposed by revising the constant term in intercept c0 for the collected ten models. The better models with an ideal revising possibility or flexibility in the collected ten models have been selected and recommended.

  15. Critical Assessment of P2O5 Activity Coefficients in CaO-based Slags during Dephosphorization Process of Iron-based Melts

    NASA Astrophysics Data System (ADS)

    Yang, Xue-min; Li, Jin-yan; Chai, Guo-Ming; Duan, Dong-ping; Zhang, Jian

    2016-08-01

    According to the experimental results of hot metal dephosphorization by CaO-based slags at a commercial-scale hot metal pretreatment station, activity a_{{{{P}}_{ 2} {{O}}_{ 5} }} of P2O5 in the CaO-based slags has been determined using the calculated comprehensive mass action concentration N_{{{{Fe}}t {{O}}}}{} of iron oxides by the ion and molecule coexistence theory (IMCT) for representing the reaction ability of Fe t O, i.e., activity of a_{{{{Fe}}t {{O}}}}{} . The collected ten models from the literature for predicting activity coefficient γ_{{{{P}}_{ 2} {{O}}_{ 5} }} of P2O5 in CaO-based slags have been evaluated based on the determined activity a_{{{{P}}_{ 2} {{O}}_{ 5} }} of P2O5 by the IMCT as the criterion. The collected ten models of activity coefficient γ_{{{{P}}_{ 2} {{O}}_{ 5} }} of P2O5 in CaO-based slags can be described in the form of a linear function as log γ_{{{{P}}_{ 2} {{O}}_{ 5} }} ≡ y = c0 + c1 x , in which independent variable x represents the chemical composition of slags, intercept c0 including the constant term depicts temperature effect and other unmentioned or acquiescent thermodynamic factors, and slope c1 is regressed by the experimental results. Thus, a general approach for obtaining good prediction results of activity a_{{{{P}}_{ 2} {{O}}_{ 5} }} of P2O5 in CaO-based slags is proposed by revising the constant term in intercept c0 for the collected ten models. The better models with an ideal revising possibility or flexibility in the collected ten models have been selected and recommended.

  16. Effect of ca2+ to salicylic acid release in pectin based controlled drug delivery system

    NASA Astrophysics Data System (ADS)

    Kistriyani, L.; Wirawan, S. K.; Sediawan, W. B.

    2016-01-01

    Wastes from orange peel are potentially be utilized to produce pectin, which are currently an import commodity. Pectin can be used in making edible film. Edible films are potentially used as a drug delivery system membrane after a tooth extraction. Drug which is used in the drug delivery system is salicylic acid. It is an antiseptic. In order to control the drug release rate, crosslinking process is added in the manufacturing of membrane with CaCl2.2H2O as crosslinker. Pectin was diluted in water and mixed with a plasticizer and CaCl2.2H2O solution at 66°C to make edible film. Then the mixture was dried in an oven at 50 °C. After edible film was formed, it was coated using plasticizer and CaCl2.2H2O solution with various concentration 0, 0.015, 0.03 and 0.05g/mL. This study showed that the more concentration of crosslinker added, the slower release of salicylic acid would be. This was indicated by the value of diffusivites were getting smaller respectively. The addition of crosslinker also caused smaller gels swelling value,which made the membrane is mechanically stronger

  17. Radar Scan Strategies for the Patrick Air Force Base Weather Surveillance Radar, Model-74C, Replacement

    NASA Technical Reports Server (NTRS)

    Short, David

    2008-01-01

    The 45th Weather Squadron (45 WS) is replacing the Weather Surveillance Radar, Model 74C (WSR-74C) at Patrick Air Force Base (PAFB), with a Doppler, dual polarization radar, the Radtec 43/250. A new scan strategy is needed for the Radtec 43/250, to provide high vertical resolution data over the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) launch pads, while taking advantage of the new radar's advanced capabilities for detecting severe weather phenomena associated with convection within the 45 WS area of responsibility. The Applied Meteorology Unit (AMU) developed several scan strategies customized for the operational needs of the 45 WS. The AMU also developed a plan for evaluating the scan strategies in the period prior to operational acceptance, currently scheduled for November 2008.

  18. Force-Based Puncture Detection and Active Position Holding for Assisted Retinal Vein Cannulation*

    PubMed Central

    Gonenc, Berk; Tran, Nhat; Riviere, Cameron N.; Gehlbach, Peter; Taylor, Russell H.; Iordachita, Iulian

    2016-01-01

    Retinal vein cannulation is a demanding procedure proposed to treat retinal vein occlusion by direct therapeutic agent delivery methods. Challenges in identifying the moment of venous puncture, achieving cannulation and maintaining cannulation during drug delivery currently limit the feasibility of the procedure. In this study, we respond to these problems with an assistive system combining a handheld micromanipulator, Micron, with a force-sensing microneedle. The integrated system senses the instant of vein puncture based on measured forces and the position of the needle tip. The system actively holds the cannulation device securely in the vein following cannulation and during drug delivery. Preliminary testing of the system in a dry phantom, stretched vinyl membranes, demonstrates a significant improvement in the total time the needle could be maintained stably inside of the vein. This was especially evident in smaller veins and is attributed to decreased movement of the positioned cannula following venous cannulation. PMID:27127804

  19. Centrifugal Force Based Magnetic Micro-Pump Driven by Rotating Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Kim, S. H.; Hashi, S.; Ishiyama, K.

    2011-01-01

    This paper presents a centrifugal force based magnetic micro-pump for the pumping of blood. Most blood pumps are driven by an electrical motor with wired control. To develop a wireless and battery-free blood pump, the proposed pump is controlled by external rotating magnetic fields with a synchronized impeller. Synchronization occurs because the rotor is divided into multi-stage impeller parts and NdFeB permanent magnet. Finally, liquid is discharged by the centrifugal force of multi-stage impeller. The proposed pump length is 30 mm long and19 mm in diameter which much smaller than currently pumps; however, its pumping ability satisfies the requirement for a blood pump. The maximum pressure is 120 mmHg and the maximum flow rate is 5000ml/min at 100 Hz. The advantage of the proposed pump is that the general mechanical problems of a normal blood pump are eliminated by the proposed driving mechanism.

  20. High-force NdFeB-based magnetic tweezers device optimized for microrheology experiments

    SciTech Connect

    Lin Jun; Valentine, Megan T.

    2012-05-15

    We present the design, calibration, and testing of a magnetic tweezers device that employs two pairs of permanent neodymium iron boron magnets surrounded by low-carbon steel focusing tips to apply large forces to soft materials for microrheology experiments. Our design enables the application of forces in the range of 1-1800 pN to {approx}4.5 {mu}m paramagnetic beads using magnet-bead separations in the range of 0.3-20 mm. This allows the use of standard coverslips and sample geometries. A high speed camera, custom LED-based illumination scheme, and mechanically stabilized measurement platform are employed to enable the measurement of materials with viscoelastic moduli as high as {approx}1 kPa.

  1. Annular force based variable curvature mirror aiming to realize non-moving element optical zooming

    NASA Astrophysics Data System (ADS)

    Zhao, Hui; Xie, Xiaopeng; Wei, Jingxuan; Ren, Guorui; Pang, Zhihai; Xu, Liang

    2015-10-01

    Recently, a new kind of optical zooming technique in which no moving elements are involved has been paid much attention. The elimination of moving elements makes optical zooming suitable for applications which has exacting requirements in space, power cost and system stability. The mobile phone and the space-borne camera are two typical examples. The key to realize non-moving elements optical zooming lies in the introduction of variable curvature mirror (VCM) whose radius of curvature could be changed dynamically. When VCM is about to be used to implement optical zoom imaging, two characteristics should be ensured. First, VCM has to provide large enough saggitus variation in order to obtain a big magnification ratio. Second, after the radius of curvature has been changed, the corresponding surface figure accuracy should still be maintained superior to a threshold level to make the high quality imaging possible. In this manuscript, based on the elasticity theory, the physical model of the annular force based variable curvature mirror is established and numerically analyzed. The results demonstrate that when the annular force is applied at the half-the-aperture position, the actuation force is reduced and a smaller actuation force is required to generate the saggitus variation and thus the maintenance of surface figure accuracy becomes easier during the variation of radius of curvature. Besides that, a prototype VCM, whose diameter and thickness are 100mm and 3mm respectively, have been fabricated and the maximum saggitus variation that could be obtained approaches more than 30 wavelengths. At the same time, the degradation of surface figure accuracy is weakly correlated to the curvature radius variation. Keywords: optical zooming; variable curvature mirror; surface figure accuracy; saggitus;

  2. Development of a novel liquid crystal based cell traction force transducer system.

    PubMed

    Soon, C F; Youseffi, M; Berends, R F; Blagden, N; Denyer, M C T

    2013-01-15

    Keratinocyte traction forces play a crucial role in wound healing. The aim of this study was to develop a novel cell traction force (CTF) transducer system based on cholesteryl ester liquid crystals (LC). Keratinocytes cultured on LC induced linear and isolated deformation lines in the LC surface. As suggested by the fluorescence staining, the deformation lines appeared to correlate with the forces generated by the contraction of circumferential actin filaments which were transmitted to the LC surface via the focal adhesions. Due to the linear viscoelastic behavior of the LC, Hooke's equation was used to quantify the CTFs by associating Young's modulus of LC to the cell induced stresses and biaxial strain in forming the LC deformation. Young's modulus of the LC was profiled by using spherical indentation and determined at approximately 87.1±17.2kPa. A new technique involving cytochalasin-B treatment was used to disrupt the intracellular force generating actin fibers, and consequently the biaxial strain in the LC induced by the cells was determined. Due to the improved sensitivity and spatial resolution (∼1μm) of the LC based CTF transducer, a wide range of CTFs was determined (10-120nN). These were found to be linearly proportional to the length of the deformations. The linear relationship of CTF-deformations was then applied in a bespoke CTF mapping software to estimate CTFs and to map CTF fields. The generated CTF map highlighted distinct distributions and different magnitude of CTFs were revealed for polarized and non-polarized keratinocytes. PMID:22809522

  3. An Excel-based model of Ca2+ diffusion and fura 2 measurements in a spherical cell.

    PubMed

    McHugh, J M; Kenyon, J L

    2004-02-01

    We wrote a program that runs as a Microsoft Excel spreadsheet to calculate the diffusion of Ca2+ in a spherical cell in the presence of a fixed Ca2+ buffer and two diffusible Ca2+ buffers, one of which is considered to be a fluorescent Ca2+ indicator. We modeled Ca2+ diffusion during and after Ca2+ influx across the plasma membrane with parameters chosen to approximate amphibian sympathetic neurons, mammalian adrenal chromaffin cells, and rat dorsal root ganglion neurons. In each of these cell types, the model predicts that spatially averaged intracellular Ca2+ activity ([Ca2+]avg) rises to a high peak and starts to decline promptly on the termination of Ca2+ influx. We compared [Ca2+]avg with predictions of ratiometric Ca2+ measurements analyzed in two ways. Method 1 sums the fluorescence at each of the two excitation or emission wavelengths over the N compartments of the model, calculates the ratio of the summed signals, and converts this ratio to Ca2+ ([Ca2+]avg,M1). Method 2 sums the measured number of moles of Ca2+ in each of the N compartments and divides by the volume of the cell ([Ca2+]avg,M2). [Ca2+]avg,M1 peaks well after the termination of Ca2+ influx at a value substantially less than [Ca2+]avg because the summed signals do not reflect the averaged free Ca2+ if the signals come from compartments containing gradients in free Ca2+ spanning nonlinear regions of the relationship between free Ca2+ and the fluorescence signals. In contrast, [Ca2+]avg,M2 follows [Ca2+]avg closely. PMID:14512292

  4. Patrick Air Force Base integrated resource assessment. Volume 2, Baseline detail

    SciTech Connect

    Wahlstrom, R.R.; King, D.A.; Parker, S.A.; Sandusky, W.F.

    1993-08-01

    The US Air Force has tasked the Pacific Northwest Laboratory (PNL), in support of the US Department of Energy (DOE) Federal Energy Management Program (FEMP), to assess energy use at Patrick Air Force Base (AFB). The information obtained from this assessment will be used in identifying energy resource opportunities to reduce overall energy consumption on the base. The primary focus of this report is to assess the current baseline energy consumption at Patrick AFB. It is a comparison report to Volume 1, the Executive Summary, and Volume 3, the Resource Assessment. This assessment requires that information be obtained and characterized for buildings, utilities, energy sources, energy uses, and load profile information to be used to improve the characterization of energy use on the base. The characteristics of electricity, natural gas, and No. 2 fuel oil are analyzed for on-base facilities and housing. The assessment examines basic regional information used to determine energy-use intensity (EUI) values for Patrick AFB facilities by building, fuel type, and energy end use. It also provides a summary of electricity consumption from Florida Power and Light Company (FPL) metered data for 1985-1991. Load profile information obtained from FPL data is presented for the north and south substations for the four seasons of the year, including weekdays and weekends.

  5. Fall 1994 wildlife and vegetation survey, Norton Air Force Base, California

    SciTech Connect

    Not Available

    1994-12-15

    The fall 1994 wildlife and vegetation surveys were completed October 3-7, 1994, at Norton Air Force Base (AFB), California. Two biologists from CDM Federal Programs, the U.S. Environmental Protection Agency (EPA) regional biologist and the Oak Ridge National Laboratory (ORNL) lead biologist conducted the surveys. A habitat assessment of three Installation Restoration Project (IRP) sites at Norton Air Force Base was also completed during the fall survey period. The IRP sites include: Landfill No. 2 (Site 2); the Industrial Wastewater Treatment Plant (IWTP) area; and Former Fire Training Area No. 1 (Site 5). The assessments were designed to qualitatively characterize the sites of concern, identify potential ecological receptors, and provide information for Remedial Design/Remedial Action activities. A Reference Area (Santa Ana River Wash) and the base urban areas were also characterized. The reference area assessment was performed to provide a baseline for comparison with the IRP site habitats. The fall 1994 survey is the second of up to four surveys that may be completed. In order to develop a complete understanding of all plant and animal species using the base, these surveys were planned to be conducted over four seasons. Species composition can vary widely during the course of a year in Southern California, and therefore, seasonal surveys will provide the most complete and reliable data to address changes in habitat structure and wildlife use of the site. Subsequent surveys will focus on seasonal wildlife observations and a spring vegetation survey.

  6. Sting-free Unsteady Flowfield, Base Pressure and Force Measurements on Axisymmetric Bluff-Body

    NASA Astrophysics Data System (ADS)

    Higuchi, Hiroshi; Sawada, Hideo; Kato, Hiroyuki; Kunimasu, Tetsuya

    2006-11-01

    To avoid interference of model support, flowfields as well as aerodynamic force and base pressure on blunt short cylinders in axial flow were measured at Re=100,000 with the JAXA 60cm magnetic suspension and balance system. The fineness ratio ranged from 1.27 to 1.79. A digital telemeter system was developed for the base pressure measurement, and the velocity field was obtained using a PIV system. Vortices along separating shear layer and shear layer flappings with or without reattachment on the wall were observed. Downstream the cylinder in the azimuthal plane, PIV snapshots showed large-scale motion of longitudinal vortices. These instantaneous flowfields presented excellent axisymmetry when they were ensemble-averaged. Mean base pressure agreed with the drag variation at different fineness ratios. The present magnetic suspension and balance system allowed evaluation of low frequency unsteady aerodynamic force vector from feedback current to the coils and the detected small model movement. Base pressure fluctuations were compared with the drag fluctuations and discussed in light of overall flowfield phenomena.

  7. Groundwater level and nitrate concentration trends on Mountain Home Air Force Base, southwestern Idaho

    USGS Publications Warehouse

    Williams, Marshall L.

    2014-01-01

    Mountain Home Air Force Base in southwestern Idaho draws most of its drinking water from the regional aquifer. The base is located within the State of Idaho's Mountain Home Groundwater Management Area and is adjacent to the State's Cinder Cone Butte Critical Groundwater Area. Both areas were established by the Idaho Department of Water Resources in the early 1980s because of declining water levels in the regional aquifer. The base also is listed by the Idaho Department of Environmental Quality as a nitrate priority area. The U.S. Geological Survey, in cooperation with the U.S. Air Force, began monitoring wells on the base in 1985, and currently monitors 25 wells for water levels and 17 wells for water quality, primarily nutrients. This report provides a summary of water-level and nitrate concentration data collected primarily between 2001 and 2013 and examines trends in those data. A Regional Kendall Test was run to combine results from all wells to determine an overall regional trend in water level. Groundwater levels declined at an average rate of about 1.08 feet per year. Nitrate concentration trends show that 3 wells (18 percent) are increasing in nitrate concentration trend, 3 wells (18 percent) show a decreasing nitrate concentration trend, and 11 wells (64 percent) show no nitrate concentration trend. Six wells (35 percent) currently exceed the U.S. Environmental Protection Agency's maximum contaminant limit of 10 milligrams per liter for nitrate (nitrite plus nitrate, measured as nitrogen).

  8. Development and implementation of configurational forces based constitutive phase field models for shape memory alloys

    NASA Astrophysics Data System (ADS)

    Agboola, Babatunde Omogbolahan

    Continuum thermodynamic constitutive phase field models are developed to simulate the rate dependent, thermomechanical response and precipitate formation in shape memory alloys (SMAs). The two models are based on the application of the balance of configurational forces, a scalar order parameter (a phase field) and atomic concentration to extend standard continuum thermodynamics approach. Constitutive field equations that capture the kinetics of solid-solid martensitic phase transition in SMA and the diffusion mediated precipitate formation in an elastic solid are developed. The coupled set of thermodynamically consistent field equations results from balance of configuration forces, balance of linear momentum, balance of energy and balance of atomic species mass. The field equations capture the kinetics of phase transition, deformation and elastic wave, heat transfer and atomic diffusion respectively. The first model is thermomechanical and is used to simulate the macroscopic response of SMA such as pseudoelasticity; transformation induced pseudo-creep, stress relaxation as well as the effect of cooling rate on mechanical and thermally induced phase transformation of SMA. The second model couples diffusion with elasticity to simulate growth and coarsening of precipitate and experimentally observed concentration depletion near the precipitates Results of the simulations of the macroscopic SMA response are in very good agreement with experimental observation. Simulations suggest that rate dependent and complex thermomechanical response of SMA are due to the interaction of an inherent time scale ( as well as length scale) of phase transformation, introduced through the balance of configurational forces, with other time scales. This work contributes to improved SMA modeling, scientific understanding and design. In particular, for aerospace application under stringent requirement and severe environmental conditions. Contribution of fundamental use of balance of

  9. Micromachined diffraction based optical microphones and intensity probes with electrostatic force feedback

    NASA Astrophysics Data System (ADS)

    Bicen, Baris

    Measuring acoustic pressure gradients is critical in many applications such as directional microphones for hearing aids and sound intensity probes. This measurement is especially challenging with decreasing microphone size, which reduces the sensitivity due to small spacing between the pressure ports. Novel, micromachined biomimetic microphone diaphragms are shown to provide high sensitivity to pressure gradients on one side of the diaphragm with low thermal mechanical noise. These structures have a dominant mode shape with see-saw like motion in the audio band, responding to pressure gradients as well as spurious higher order modes sensitive to pressure. In this dissertation, integration of a diffraction based optical detection method with these novel diaphragm structures to implement a low noise optical pressure gradient microphone is described and experimental characterization results are presented, showing 36 dBA noise level with 1mm port spacing, nearly an order of magnitude better than the current gradient microphones. The optical detection scheme also provides electrostatic actuation capability from both sides of the diaphragm separately which can be used for active force feedback. A 4-port electromechanical equivalent circuit model of this microphone with optical readout is developed to predict the overall response of the device to different acoustic and electrostatic excitations. The model includes the damping due to complex motion of air around the microphone diaphragm, and it calculates the detected optical signal on each side of the diaphragm as a combination of two separate dominant vibration modes. This equivalent circuit model is verified by experiments and used to predict the microphone response with different force feedback schemes. Single sided force feedback is used for active damping to improve the linearity and the frequency response of the microphone. Furthermore, it is shown that using two sided force feedback one can significantly suppress

  10. Visualiser of two-micron laser radiation based on Ho:CaF{sub 2} crystals

    SciTech Connect

    Lyapin, A A; Ryabochkina, P A; Ushakov, S N; Fedorov, P P

    2014-06-30

    The anti-Stokes luminescence spectra of Ho:CaF{sub 2} crystals corresponding to the {sup 5}G{sub 4} → {sup 5}I{sub 8}, {sup 5}G{sub 5} → {sup 5}I{sub 8}, {sup 5}F{sub 3} → {sup 5}I{sub 8}, {sup 5}F{sub 4}({sup 5}S{sub 2}) → {sup 5}I{sub 8}, {sup 5}F{sub 5} → {sup 5}I{sub 8}, {sup 5}S{sub 2} → {sup 5}I{sub 7}, {sup 5}I{sub 4} → {sup 5}I{sub 8}, {sup 5}I{sub 5} → {sup 5}I{sub 8}, {sup 5}F{sub 5} → {sup 5}I{sub 7}, {sup 5}F{sub 3} → {sup 5}I{sub 6}, {sup 5}I{sub 6} → {sup 5}I{sub 8}, {sup 5}F{sub 5} → {sup 5}I{sub 6}, and {sup 5}I{sub 5} → {sup 5}I{sub 7} transitions upon excitation of the {sup 5}I{sub 7} level of Ho{sup 3+} ions are studied. A method for visualisation of IR radiation in the two-micron range using Ho:CaF{sub 2} crystals is proposed. The energy efficiency of conversion of two-micron laser radiation to radiation in the red spectral range 620 – 690 nm by a 1 mol % HoF{sub 3}:CaF{sub 2} crystal is estimated to be no higher than 0.02%. (nonlinear optical phenomena)

  11. A Polarizable Multipole-based Force Field for Dimethyl and Trimethyl Phosphate

    PubMed Central

    Zhang, Changsheng; Lu, Chao; Wang, Qiantao; Ponder, Jay W.; Ren, Pengyu

    2016-01-01

    Using quantum mechanical studies and liquid phase simulations, the AMOEBA force field for dimethylphosphate (DMP) ion and trimethylphosphate (TMP) has been developed. Based on ab initio calculations, it was found that ion binding and the solution environment significantly impact both the molecular geometry and the energy differences between conformations. Atomic multipole moments are derived from MP2/cc-pVQZ calculations of methyl phosphates at several conformations with accounting of chemical environments. Many-body polarization is handled via a Thole-style induction model using distributed atomic polarizabilities. Van der Waals parameters of phosphate and oxygen atoms are determined by fitting to the quantum mechanical interaction energy curves for water with DMP or TMP. Additional stretch-torsion and angle-torsion coupling terms were introduced in order to capture asymmetry in P-O bond lengths and angles due to the generalized anomeric effect. The resulting force field for DMP and TMP is able to accurately describe both the molecular structure and conformational energy surface, including bond and angle variations with conformation, as well as interaction of both species with water and metal ions. The force field was further validated for liquid TMP by comparing simulated density and heat of vaporization values with experimental data. Structural insight obtained from MD simulations indicates liquid TMP is stabilized by both nonpolar-nonpolar contacts and hydrogen bonding. The current study is an important step towards developing the AMOEBA model for nucleic acids. PMID:26574325

  12. Shemya Air Force Base, Alaska No Further Action Decision document for Hg-1

    SciTech Connect

    Not Available

    1993-03-05

    This document is being prepared to document that a No Further Action Decision (NFAD) document is appropriate for the Hg-1 site at Shemya Air Force Base (AFB), Alaska, under the Air Force Installation Restoration Program (IRP). The IRP is a Department of Defense (DOD) program established to identify and remediate hazardous waste problems on DOD property that result from past practices. The Alaska Department of Environmental Conservation (ADEC) draft document [open quotes]No Further Action Criteria for DOD Military/FUD Sites[close quotes] has been used as a guide in preparing this document. Air Force personnel have stated that the Hg-1 site may have been used to store mercury and PCB-contaminated material. The site was added to the IRP in 1987, and later that year a field investigation was conducted at the site. Soil samples were collected and analyzed for mercury, EP toxicity, polychlorinated biphenyls (PCBs), and dioxin. All concentrations of contaminants found in Area Hg-1 are below regulatory action levels for PCBs (40 CFR 761) and mercury (55 FR 30798) or below detection levels for dioxin/furans. Therefore, leaving these soils in place is acceptable.

  13. Shemya Air Force Base, Alaska No Further Action Decision document for Hg-1. Final report

    SciTech Connect

    Not Available

    1993-03-05

    This document is being prepared to document that a No Further Action Decision (NFAD) document is appropriate for the Hg-1 site at Shemya Air Force Base (AFB), Alaska, under the Air Force Installation Restoration Program (IRP). The IRP is a Department of Defense (DOD) program established to identify and remediate hazardous waste problems on DOD property that result from past practices. The Alaska Department of Environmental Conservation (ADEC) draft document {open_quotes}No Further Action Criteria for DOD Military/FUD Sites{close_quotes} has been used as a guide in preparing this document. Air Force personnel have stated that the Hg-1 site may have been used to store mercury and PCB-contaminated material. The site was added to the IRP in 1987, and later that year a field investigation was conducted at the site. Soil samples were collected and analyzed for mercury, EP toxicity, polychlorinated biphenyls (PCBs), and dioxin. All concentrations of contaminants found in Area Hg-1 are below regulatory action levels for PCBs (40 CFR 761) and mercury (55 FR 30798) or below detection levels for dioxin/furans. Therefore, leaving these soils in place is acceptable.

  14. Measuring protein isoelectric points by AFM-based force spectroscopy using trace amounts of sample.

    PubMed

    Guo, Shifeng; Zhu, Xiaoying; Jańczewski, Dominik; Lee, Serina Siew Chen; He, Tao; Teo, Serena Lay Ming; Vancso, G Julius

    2016-09-01

    Protein charge at various pH and isoelectric point (pI) values is important in understanding protein function. However, often only trace amounts of unknown proteins are available and pI measurements cannot be obtained using conventional methods. Here, we show a method based on the atomic force microscope (AFM) to determine pI using minute quantities of proteins. The protein of interest is immobilized on AFM colloidal probes and the adhesion force of the protein is measured against a positively and a negatively charged substrate made by layer-by-layer deposition of polyelectrolytes. From the AFM force-distance curves, pI values with an estimated accuracy of ±0.25 were obtained for bovine serum albumin, myoglobin, fibrinogen and ribonuclease A over a range of 4.7-9.8. Using this method, we show that the pI of the 'footprint' of the temporary adhesive proteins secreted by the barnacle cyprid larvae of Amphibalanus amphitrite is in the range 9.6-9.7. PMID:27454881

  15. Polarizable Empirical Force Field for Acyclic Poly-Alcohols Based on the Classical Drude Oscillator

    PubMed Central

    He, Xibing; Lopes, Pedro E. M.; MacKerell, Alexander D.

    2014-01-01

    A polarizable empirical force field for acyclic polyalcohols based on the classical Drude oscillator is presented. The model is optimized with an emphasis on the transferability of the developed parameters among molecules of different sizes in this series and on the condensed-phase properties validated against experimental data. The importance of the explicit treatment of electronic polarizability in empirical force fields is demonstrated in the cases of this series of molecules with vicinal hydroxyl groups that can form cooperative intra- and intermolecular hydrogen bonds. Compared to the CHARMM additive force field, improved treatment of the electrostatic interactions avoids overestimation of the gas-phase dipole moments, results in significant improvement in the treatment of the conformational energies, and leads to the correct balance of intra- and intermolecular hydrogen bonding of glycerol as evidenced by calculated heat of vaporization being in excellent agreement with experiment. Computed condensed phase data, including crystal lattice parameters and volumes and densities of aqueous solutions are in better agreement with experimental data as compared to the corresponding additive model. Such improvements are anticipated to significantly improve the treatment of polymers in general, including biological macromolecules. PMID:23703219

  16. Comparison of Brownian-dynamics-based estimates of polymer tension with direct force measurements

    PubMed Central

    Arsenault, Mark E.; Purohit, Prashant K.; Goldman, Yale E.; Shuman, Henry; Bau, Haim H.

    2013-01-01

    With the aid of Brownian dynamics models, it is possible to estimate polymer tension by monitoring polymers’ transverse thermal fluctuations. To assess the precision of the approach, Brownian dynamics-based tension estimates were compared with the force applied to rhodamine-phalloidin labeled actin filaments bound to polymer beads and suspended between two optical traps. The transverse thermal fluctuations of each filament were monitored with a CCD camera, and the images were analyzed to obtain the filament’s transverse displacement variance as a function of position along the filament, the filament’s tension, and the camera’s exposure time. A linear Brownian dynamics model was used to estimate the filament’s tension. The estimated force was compared and agreed within 30% (when the tension <0.1 pN) and 70% (when the tension <1 pN) with the applied trap force. In addition, the paper presents concise asymptotic expressions for the mechanical compliance of a system consisting of a filament attached tangentially to bead handles (dumbbell system). The techniques described here can be used for noncontact estimates of polymers’ and fibers’ tension. PMID:21230516

  17. Magnetic tweezers-based force clamp reveals mechanically distinct apCAM domain interactions.

    PubMed

    Kilinc, Devrim; Blasiak, Agata; O'Mahony, James J; Suter, Daniel M; Lee, Gil U

    2012-09-19

    Cell adhesion molecules of the immunoglobulin superfamily (IgCAMs) play a crucial role in cell-cell interactions during nervous system development and function. The Aplysia CAM (apCAM), an invertebrate IgCAM, shares structural and functional similarities with vertebrate NCAM and therefore has been considered as the Aplysia homolog of NCAM. Despite these similarities, the binding properties of apCAM have not been investigated thus far. Using magnetic tweezers, we applied physiologically relevant, constant forces to apCAM-coated magnetic particles interacting with apCAM-coated model surfaces and characterized the kinetics of bond rupture. The average bond lifetime decreased with increasing external force, as predicted by theoretical considerations. Mathematical simulations suggest that the apCAM homophilic interaction is mediated by two distinct bonds, one involving all five immunoglobulin (Ig)-like domains in an antiparallel alignment and the other involving only two Ig domains. In summary, this study provides biophysical evidence that apCAM undergoes homophilic interactions, and that magnetic tweezers-based, force-clamp measurements provide a rapid and reliable method for characterizing relatively weak CAM interactions. PMID:22995484

  18. [The organizational bases for the building of a modern medical support system for the Armed Forces].

    PubMed

    Chizh, I M

    1996-01-01

    In the article the problems concerning characteristic features of the local wars and armed conflicts, organization bases of construction of The Army and Fleet medical support modern system are discussed. The organization of personnel medical security is considered depending on the duration, intensity and spatial scope of military conflict, peculiarities of group (forces) application and ways of military actions conduction. The distribution of federal troops sanitary losses during the war in Chechenskaya Republic is shown depending on the type, localization and degree of injuries gravity as well as volume of the wounded and invalids evacuation by air transport and work of military medical institutions. The following principles of construction of the Armed Forces medical support system are formulated: The system must be in compliance with troops goals, structure, strategy and tactics, its specificity; development of medical security forms and methods, their historicism; interdependency, completeness and integrity of the system's elements; territorial aspects of its construction and management optimization. Considering character of the goals being laid on the Mobile Forces the paramount importance is attached to the level of readiness of medical service and its formations and units to act in crisis situations. PMID:8659162

  19. GROMOS 53A6GLYC, an Improved GROMOS Force Field for Hexopyranose-Based Carbohydrates.

    PubMed

    Pol-Fachin, Laercio; Rusu, Victor H; Verli, Hugo; Lins, Roberto D

    2012-11-13

    An improved parameter set for explicit-solvent simulations of carbohydrates (referred to as GROMOS 53A6GLYC) is presented, allowing proper description of the most stable conformation of all 16 possible aldohexopyranose-based monosaccharides. This set includes refinement of torsional potential parameters associated with the determination of hexopyranose rings conformation by fitting to their corresponding quantum-mechanical profiles. Other parameters, as the rules for third and excluded neighbors, are taken directly from the GROMOS 53A6 force field. Comparisons of the herein presented parameter set to our previous version (GROMOS 45A4), the GLYCAM06 force field, and available NMR data are presented in terms of ring puckering free energies, conformational distribution of the hydroxymethyl group, and glycosidic linkage geometries for 16 selected monosaccharides and eight disaccharides. The proposed parameter modifications have shown a significant improvement for the above-mentioned quantities over the two tested force fields, while retaining full compatibility with the GROMOS 53A6 and 54A7 parameter sets for other classes of biomolecules. PMID:26605624

  20. Hydration and proton transport in solid solutions based on Ba2CaWO6

    NASA Astrophysics Data System (ADS)

    Animitsa, I. E.; Kochetova, N. A.; Denisova, T. A.; Zhuravlev, N. A.; Baklanova, I. V.

    2009-02-01

    Hydrated alkaline-earth metal tungstates Ba4Ca2 + x W2 - x O12 - 2 x with perovskite structure were studied by the thermogravimetry, 1H NMR, IR, and Raman spectroscopy methods. Electrical conductivity and transfer numbers were measured with varying T, p_{O_2 } and p_{H_2 O} . The solid solutions are capable of reversibly intercalating water and can exhibit high-temperature proton transport. The localization of protons on oxygen results in the appearance of energetically nonequivalent OH groups; a small fraction of protons are present in the form of H2O and H3O+.

  1. Soft Pushing Operation with Dual Compliance Controllers Based on Estimated Torque and Visual Force

    NASA Astrophysics Data System (ADS)

    Muis, Abdul; Ohnishi, Kouhei

    Sensor fusion extends robot ability to perform more complex tasks. An interesting application in such an issue is pushing operation, in which through multi-sensor, the robot moves an object by pushing it. Generally, a pushing operation consists of “approaching, touching, and pushing"(1). However, most researches in this field are dealing with how the pushed object follows the predefined trajectory. In which, the implication as the robot body or the tool-tip hits an object is neglected. Obviously on collision, the robot momentum may crash sensor, robot's surface or even the object. For that reason, this paper proposes a soft pushing operation with dual compliance controllers. Mainly, a compliance control is a control system with trajectory compensation so that the external force may be followed. In this paper, the first compliance controller is driven by estimated external force based on reaction torque observer(2), which compensates contact sensation. The other one compensates non-contact sensation. Obviously, a contact sensation, acquired from force sensor either reaction torque observer of an object, is measurable once the robot touched the object. Therefore, a non-contact sensation is introduced before touching an object, which is realized with visual sensor in this paper. Here, instead of using visual information as command reference, the visual information such as depth, is treated as virtual force for the second compliance controller. Thus, having contact and non-contact sensation, the robot will be compliant with wider sensation. This paper considers a heavy mobile manipulator and a heavy object, which have significant momentum on touching stage. A chopstick is attached on the object side to show the effectiveness of the proposed method. Here, both compliance controllers adjust the mobile manipulator command reference to provide soft pushing operation. Finally, the experimental result shows the validity of the proposed method.

  2. Design of a MEMS-based motion stage based on a lever mechanism for generating large displacements and forces

    NASA Astrophysics Data System (ADS)

    Kim, Yong-Sik; Shi, Hongliang; Dagalakis, Nicholas G.; Gupta, Satyandra K.

    2016-09-01

    Conventional miniaturized motion stages have a volume of 50–60 cm3 and a range of motion around 100 μm. Micro-electro-mechanical systems (MEMS)-based motion stages have been good alternatives in some applications for small footprint, micron-level accuracy, and a lower cost. However, existing MEMS-based motion stages are able to provide a force of μN level, small displacements (less than tens of microns), and need additional features for practical applications like a probe or a stage. In this paper, a single degree of freedom motion stage is designed and analyzed for a larger displacement, a larger output force, a smaller out-of-plane deformation, and a bigger moving stage for further applications. For these purposes, the presented motion stage is designed with a thermal actuator, folded springs, and a lever, and it is experimentally characterized. Furthermore, three different types of flexure joints are investigated to characterize their capabilities and suitability to serve as the revolute joint of the lever: a beam, a cartwheel, and a butterfly flexure. The presented motion stage has a moving stage of 15 mm  ×  15 mm and shows a maximum displacement over 80 μm, and out-of-plane deformation under a weight of 120 μN less than 2 μm. The force generated by the actuator is estimated to be 68.6 mN.

  3. 4. Credit USAF, ca. 1945. Original housed in the Photograph ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. Credit USAF, ca. 1945. Original housed in the Photograph Files, AFFTC/HO, Edwards AFB, California. Low level oblique aerial view of Muroc Flight Test Base (North Base), looking southwest along flightline. HANG-P-A hangar (Building 4505) is in the right foreground. A Bell XP-59A Airacomet, the United States military's first jet propelled aircraft, is being towed on the apron toward the control tower. Other aircraft in the foreground include Douglas DC-3s, North American Aviation P-51 Mustangs, and Lockheed P-38 Lightnings. - Edwards Air Force Base, North Base, North Base Road, Boron, Kern County, CA

  4. Using the PhysX engine for Physics-based Virtual Surgery with Force Feedback

    PubMed Central

    Maciel, Anderson; Halic, Tansel; Lu, Zhonghua; Nedel, Luciana P.; De, Suvranu

    2010-01-01

    Background The development of modern surgical simulators is highly challenging as they must support complex simulation environments. The demand for higher realism in such simulators has driven researchers to adopt physics-based models which are computationally very demanding. This poses a major problem since real time interactions must permit graphical updates of 30 Hz and a much higher rate of 1 kHz for force feedback (haptics). Recently several physics engines have been developed which offer multi-physics simulation capabilities including rigid and deformable bodies, cloth and fluids. While such physics engines provide unique opportunities for the development of surgical simulators, their higher latencies, compared to what is necessary for real time graphics and haptics, offer significant barriers to their use in interactive simulation environments. Methods In this work, we propose solutions to this problem and demonstrate how a multimodal surgical simulation environment may be developed based on NVIDIA’s PhysX physics library. Hence, models that are undergoing relatively low frequency updates in PhysX can exist in an environment that demands much higher frequency updates for haptics. We use a collision handling layer to interface between the physical response provided by PhysX and the haptic rendering device to provide both real time tissue response and force feedback. Results Our simulator integrates a bimanual haptic interface for force-feedback and per-pixel shaders for graphics realism in real time. To demonstrate the effectiveness of our approach, we present the simulation of the Laparoscopic Adjustable Gastric Banding (LAGB) procedure as a case study. Conclusions To develop complex and realistic surgical trainers with realistic organ geometries and tissue properties demands stable physics-based deformation methods which are not always compatible with the interaction level required for such trainers. We have shown that combining different modeling

  5. Evaluation of Sr/Ca-based paleoclimate reconstructions in modern and Medieval Diploria strigosa corals in the northeastern Caribbean

    NASA Astrophysics Data System (ADS)

    Xu, Y.; Pearson, S. P.; Kilbourne, K.

    2013-12-01

    Tropical sea surface temperature (SST) has been implicated as a driver of climate changes during the Medieval Climate Anomaly (MCA, 950-1300 A.D.) but little data exists from the tropical oceans during this time period. We collected three modern and seven sub-fossil Diploria strigosa coral colonies from an overwash deposit on Anegada, British Virgin Islands (18.73 °N, 63.33 °W) in order to reconstruct climate in the northeastern Caribbean and Tropical North Atlantic during the MCA. The first step in our reconstruction was to verify the climate signal from this species at this site. We sub-sampled the modern corals along thecal walls with an average sampling resolution of 11-13 samples per year. Sr/Ca ratios measured in the sub-samples were calibrated to temperature using three different calibration techniques (ordinary least squares, reduced major axis, and weighted least squares (WLS)) on the monthly data that includes the seasonal cycles and on the monthly anomaly data. WLS regression accounts for unequal errors in the x and y terms, so we consider it the most robust technique. The WLS regression slope between gridded SST and coral Sr/Ca is similar to the previous two calibrations of this species. Mean Sr/Ca for each of the three modern corals is 8.993 × 0.004 mmol/mol, 9.127 × 0.003 mmol/mol, and 8.960 × 0.007 mmol/mol. These straddle the mean Diploria strigosa Sr/Ca found by Giry et al., (2010), 9.080 mmol/mol, at a site with nearly the same mean SST as Anegada (27.4 °C vs. 27.5 °C). The climatological seasonal cycles for SST derived from the modern corals are statistically indistinguishable from the seasonal cycles in the instrumental SST data. The coral-based seasonal cycles have ranges of 2.70 × 0.31 °C, 2.65 × 0.08 °C and 2.71 × 0.53 °C. These results indicate that this calibration can be applied to our sub-fossil coral data. We applied the WLS calibration to monthly-resolution Sr/Ca data from multiple sub-fossil corals dating to the medieval

  6. Absolute frequency measurement of the neutral 40Ca optical frequency standard at 657 nm based on microkelvin atoms

    NASA Astrophysics Data System (ADS)

    Wilpers, G.; Oates, C. W.; Diddams, S. A.; Bartels, A.; Fortier, T. M.; Oskay, W. H.; Bergquist, J. C.; Jefferts, S. R.; Heavner, T. P.; Parker, T. E.; Hollberg, L.

    2007-04-01

    We report an absolute frequency measurement of the optical clock transition at 657 nm in 40Ca with a relative uncertainty of 7.5 × 10-15, one of the most accurate frequency measurements of a neutral atom optical transition to date. The frequency (455 986 240 494 135.8 ± 3.4) Hz was measured by stabilizing a diode laser system to a spectroscopic signal derived from an ensemble of 106 atoms cooled in two stages to a temperature of 10 µK. The measurement used a femtosecond-laser-based frequency comb to compare the Ca transition frequency with that of the single-ion 199Hg+ optical frequency standard at NIST. The Hg+ frequency was simultaneously calibrated relative to the NIST Cs fountain via the NIST time scale to yield an absolute value for the Ca transition frequency. The relative fractional instability between the two optical standards was 2 × 10-15 for 10 s of averaging time and 2 × 10-16 for 2000 s.

  7. Measurement of Contractile Activity in Small Animal's Digestive Organ by Carbon Nanotube-Based Force Transducer

    NASA Astrophysics Data System (ADS)

    Hirata, Takamichi; Takeda, Naoki; Tsutsui, Chihiro; Koike, Kanako; Shimatani, Yuichi; Sakai, Takafumi; Akiya, Masahiro; Taguchi, Akira

    2011-03-01

    A carbon nanotube (CNT)-based force transducer designed to be embedded in the body of a live animal was fabricated and implanted into the stomach of a rat omit to measure contractile movement. The transducer comprised dispersed poly(ethylene glycol)-grafted multiwalled CNTs applied to a comb-like Au-electrode formed on a poly(dimethylsiloxane) sheet. The implanted rat was injected with acetylcholine to induce muscular contractions and changes in the resistance of the transducer were measured. Such changes arise owing to strain in the CNT network upon distortion. The measured resistance change was found to be proportional to the concentration of injected acetylcholine.

  8. Radio frequency power issues and their implications to spacecraft processing at Vandenberg Air Force Base

    NASA Astrophysics Data System (ADS)

    Crean, Timothy G.

    Satellite usage of microcircuit technology for applications such as low-noise amplifiers is discussed with attention focused on the vulnerability of these devices to damage by high-power RF sources. The Vandenberg Air Force Base RF environment is described as well as a program underway which is designed to establish and control a 10 V/m RF environment at Titan payload processing facilities through a program of equipment modifications and procedural controls. It is argued that, for RF protection requirements beyond the 10 V/m range, it is necessary to incorporate RF shielding into the design of payload fairings, transporters and processing facilities.

  9. Atomic force microscopy based nanoindentation study of onion abaxial epidermis walls in aqueous environment

    NASA Astrophysics Data System (ADS)

    Xi, Xiaoning; Kim, Seong H.; Tittmann, Bernhard

    2015-01-01

    An atomic force microscopy based nanoindentation method was employed to study how the structure of cellulose microfibril packing and matrix polymers affect elastic modulus of fully hydrated primary plant cell walls. The isolated, single-layered abaxial epidermis cell wall of an onion bulb was used as a test system since the cellulose microfibril packing in this cell wall is known to vary systematically from inside to outside scales and the most abundant matrix polymer, pectin, can easily be altered through simple chemical treatments such as ethylenediaminetetraacetic acid and calcium ions. Experimental results showed that the pectin network variation has significant impacts on the cell wall modulus, and not the cellulose microfibril packing.

  10. STS-30 crew egresses OV-104 via stairway at Edwards Air Force Base (EAFB)

    NASA Technical Reports Server (NTRS)

    1989-01-01

    STS-30 crewmembers egress Atlantis, Orbiter Vehicle (OV) 104, via mobile stairway at Edwards Air Force Base (EAFB), California. Crewmembers who spent just over four full days in space are greeted by NASA Deputy Administrator Dale D. Myers and Acting NASA Administrator Richard H. Truly (waving). From bottom of the stairs to the top are Commander David M. Walker, Pilot Ronald J. Grabe, Mission Specialist (MS) Norman E. Thagard, MS Mary L. Cleave, and MS Mark C. Lee. Minutes earlier, OV-104 came to a stop at 12:44:33 pm (Pacific Daylight Time (PDT)) on EAFB concrete runway 22.

  11. STS-30 crew egresses OV-104 via stairway at Edwards Air Force Base (EAFB)

    NASA Technical Reports Server (NTRS)

    1989-01-01

    STS-30 crewmembers egress Atlantis, Orbiter Vehicle (OV) 104, via mobile stairway at Edwards Air Force Base (EAFB), California. Crewmembers who spent just over four full days in space exit OV-104 for a welcome meeting with terra firma. From bottom of the stairs to the top are Commander David M. Walker, Pilot Ronald J. Grabe, Mission Specialist (MS) Norman E. Thagard, MS Mary L. Cleave, and MS Mark C. Lee. NASA Deputy Administrator Dale D. Myers awaits at lower right to greet the crewmembers. Minutes earlier, OV-104 came to a stop at 12:44:33 pm (Pacific Daylight Time (PDT)) on EAFB concrete runway 22.

  12. Ab initio based force field and molecular dynamics simulations of crystalline TATB.

    PubMed

    Gee, Richard H; Roszak, Szczepan; Balasubramanian, Krishnan; Fried, Laurence E

    2004-04-15

    An all-atom force field for 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) is presented. The classical intermolecular interaction potential for TATB is based on single-point energies determined from high-level ab initio calculations of TATB dimers. The newly developed potential function is used to examine bulk crystalline TATB via molecular dynamics simulations. The isobaric thermal expansion and isothermal compression under hydrostatic pressures obtained from the molecular dynamics simulations are in good agreement with experiment. The calculated volume-temperature expansion is almost one dimensional along the c crystallographic axis, whereas under compression, all three unit cell axes participate, albeit unequally. PMID:15267608

  13. STS-28 crew egresses Columbia, OV-102, at Edwards Air Force Base, California

    NASA Technical Reports Server (NTRS)

    1989-01-01

    STS-28 crewmembers are greeted by NASA Associate Administrator for Space Flight William B. Lenoir, NASA Administrator Richard H. Truly, and Flight Operations Directorate (FCOD) Director Donald R. Puddy as they egress Columbia, Orbiter Vehicle (OV) 102, at Edwards Air Force Base (EAFB), California. The crew spent five days in Earth orbit for a Department of Defense (DOD) dedicated mission. The astronauts, wearing navy blue flight coveralls (jumpsuits) are, from left to right, Mission Specialist (MS) Mark N. Brown, Pilot Richard N. Richards, MS David C. Leestma, MS James C. Adamson, and Commander Brewster H. Shaw. Visible in the background are OV-102's wing and tail section and ground servicing vehicles.

  14. STS-28 crew egresses Columbia, OV-102, at Edwards Air Force Base, California

    NASA Technical Reports Server (NTRS)

    1989-01-01

    During post landing activity, the five astronaut crewmembers for STS-28 egress Columbia, Orbiter Vehicle (OV) 102, at Edwards Air Force Base (EAFB), California. The crew spent five days in Earth orbit for a Department of Defense (DOD) dedicated mission. They are greeted by NASA Associate Administrator for Space Flight William B. Lenoir and NASA Administrator Richard H. Truly. The astronauts, wearing navy blue flight coveralls (jumpsuits), are, from bottom of steps to top, Commander Brewster H. Shaw, Mission Specialist (MS) James C. Adamson, MS David C. Leestma, Pilot Richard N. Richards, and MS Mark N. Brown.

  15. Inorganic resist materials based on zirconium phosphonate for atomic force microscope lithography

    NASA Astrophysics Data System (ADS)

    Kang, Mankyu; Kim, Seonae; Jung, JinHyuck; Kim, Heebom; Shin, Inkyun; Jeon, Chanuk; Lee, Haiwon

    2014-03-01

    New inorganic resist materials based on metal complexes were investigated for atomic force microscope (AFM) lithography. Phosphoric acids are good for self-assembly because of their strong binding energy. In this work, zirconium phosphonate system are newly synthesized for spin-coatable materials in aqueous solutions and leads to negative tone pattern for improving line edge roughness. Low electron exposure by AFM lithography could generate a pattern by electrochemical reaction and cross-linking of metal-oxo complexes. It has been reported that the minimum pattern results are affected by lithographic speed, and the applied voltage between a tip and a substrate.

  16. Physically-based modeling of drag force caused by natural woody vegetation

    NASA Astrophysics Data System (ADS)

    Järvelä, J.; Aberle, J.

    2014-12-01

    Riparian areas and floodplains are characterized by woody vegetation, which is an essential feature to be accounted for in many hydro-environmental models. For applications including flood protection, river restoration and modelling of sediment processes, there is a need to improve the reliability of flow resistance estimates. Conventional methods such as the use of lumped resistance coefficients or simplistic cylinder-based drag force equations can result in significant errors, as these methods do not adequately address the effect of foliage and reconfiguration of flexible plant parts under flow action. To tackle the problem, physically-based methods relying on objective and measurable vegetation properties are advantageous for describing complex vegetation. We have conducted flume and towing tank investigations with living and artificial plants, both in arrays and with isolated plants, providing new insight into advanced parameterization of natural vegetation. The stem, leaf and total areas of the trees confirmed to be suitable characteristic dimensions for estimating flow resistance. Consequently, we propose the use of leaf area index and leaf-to-stem-area ratio to achieve better drag force estimates. Novel remote sensing techniques including laser scanning have become available for effective collection of the required data. The benefits of the proposed parameterization have been clearly demonstrated in our newest experimental studies, but it remains to be investigated to what extent the parameter values are species-specific and how they depend on local habitat conditions. The purpose of this contribution is to summarize developments in the estimation of vegetative drag force based on physically-based approaches as the latest research results are somewhat dispersed. In particular, concerning woody vegetation we seek to discuss three issues: 1) parameterization of reconfiguration with the Vogel exponent; 2) advantage of parameterizing plants with the leaf area

  17. Atomic force microscopy based nanoindentation study of onion abaxial epidermis walls in aqueous environment

    SciTech Connect

    Xi, Xiaoning; Tittmann, Bernhard; Kim, Seong H.

    2015-01-14

    An atomic force microscopy based nanoindentation method was employed to study how the structure of cellulose microfibril packing and matrix polymers affect elastic modulus of fully hydrated primary plant cell walls. The isolated, single-layered abaxial epidermis cell wall of an onion bulb was used as a test system since the cellulose microfibril packing in this cell wall is known to vary systematically from inside to outside scales and the most abundant matrix polymer, pectin, can easily be altered through simple chemical treatments such as ethylenediaminetetraacetic acid and calcium ions. Experimental results showed that the pectin network variation has significant impacts on the cell wall modulus, and not the cellulose microfibril packing.

  18. Distributions of eight meteorological variables at Cape Kennedy, Florida and Vandenberg Air Force Base, California

    NASA Technical Reports Server (NTRS)

    Graves, M. E.; King, R. L.; Brown, S. C.

    1973-01-01

    Extreme values, median values, and nine percentile values are tabulated for eight meteorological variables at Cape Kennedy, Florida and at Vandenberg Air Force Base, California. The variables are temperature, relative humidity, station pressure, water vapor pressure, water vapor mixing ratio, density, and enthalpy. For each month eight hours are tabulated, namely, 0100, 0400, 0700, 1000, 1300, 1600, 1900, and 2200 local time. These statistics are intended for general use for the space shuttle design trade-off analysis and are not to be used for specific design values.

  19. A drag-based mechanism for vertical force production in the smallest flying insects

    NASA Astrophysics Data System (ADS)

    Jones, Shannon; Laurenza, Ryan; Miller, Laura

    2013-11-01

    Previous work has shown that the flight kinematics and aerodynamics of the smallest flying insects may be significantly different than that of their larger counterparts. These small insects, such as thrips and parasitoid wasps, are on the order of 1 mm in length and operate at a Reynolds number less than 10. Due to their small size and high wing beat frequency, quantitative data on the wing kinematics of the smallest insects is not available. As a result, there has been much debate and speculation about the flight strategies employed by these insects. With the challenges associated with generating lift at low Reynolds numbers, it could be beneficial for the smallest insects to use a drag-based motion to generate some or all of its vertical force, however this has not been rigorously investigated. We used computational fluid dynamics to investigate the feasibility of drag-based propulsion in the tiniest insects. We investigated the vertical force generated by an idealized drag-based vertical stroke over a range of Reynolds numbers from 1 to 150. We also compared this stroke to more conventional hovering stroke kinematics such as that of a fruit fly and dragonfly.

  20. Operable Unit 1 remedial investigation report, Eielson Air Force Base, Alaska

    SciTech Connect

    Gilmore, T.J.; Fruland, R.M.; Liikala, T.L.

    1994-06-01

    This remedial investigation report for operable Unit 1 (OU-1) at Eielson Air Force Base presents data, calculations, and conclusions as to the nature and extent of surface and subsurface contamination at the eight source areas that make up OU-1. The information is based on the 1993 field investigation result and previous investigations. This report is the first in a set of three for OU-1. The other reports are the baseline risk assessment and feasibility study. The information in these reports will lead to a Record of Decision that will guide and conclude the environmental restoration effort for OU-1 at Eielson Air Force Base. The primary contaminants of concern include fuels and fuel-related contaminants (diesel; benzene, toluene, ethylbenzene, and xylene; total petroleum hydrocarbon; polycyclic aromatic hydrocarbons), maintenance-related solvents and cleaners (volatile chlorinated hydrocarbons such as trichloroothylene), polychlorinated biphenyls, and dichlorodiphenyltrichloroethane (DDT). The origins of contaminants of concern include leaks from storage tanks, drums and piping, and spills. Ongoing operations and past sitewide practices also contribute to contaminants of concern at OU-1 source areas. These include spraying mixed oil and solvent wastes on unpaved roads and aerial spraying of DDT.

  1. Complex terbium luminescence centers in spectral transformers based on CaSO4

    NASA Astrophysics Data System (ADS)

    Kudryavtseva, I.; Lushchik, A.; Lushchik, Ch.; Maaroos, A.; Nagirnyi, V.; Pazylbek, S.; Tussupbekova, A.; Vasil'chenko, E.

    2015-11-01

    The blue and green terbium luminescence excitation spectra (5-15 eV) at a temperature of 9 or 300 K have been measured for a set of CaSO4 : Tb3+ phosphors with calcium and terbium ions characterized by fundamental features, which were synthesized by the solid-state reaction method with variations in the composition of the raw material, the type of terbium compounds, and the concentration of introduced terbium. A comprehensive analysis of these data, emission spectra, and decay kinetics (with the rising stage) of the terbium luminescence has revealed that the main luminescence centers in an efficient phosphor with 4 at % Tb3+ each contain four closely spaced Tb3+ ions in calcium positions, as well as Na+ ions and hydrogen-containing radicals. In such complex luminescence centers, cooperative nonradiative resonant transitions in neighboring terbium ions leads to a nearly complete concentration of the terbium luminescence in the green spectral region (5 D 4 → 7 F J ). The quantum yield of the green luminescence in CaSO4 : Tb3+ (4 at %) exceeds unity, QY > 1, in the region of direct excitation of Tb3+ into the 5 d state (~5.9 eV) or excitation of oxyanions near the terbium ions (~8.1 eV).

  2. Fatigue and Fracture Behavior of a Ca-Based Bulk-Metallic Glass

    NASA Astrophysics Data System (ADS)

    Raphael, J.; Wang, G. Y.; Liaw, P. K.; Senkov, O. N.; Miracle, D. B.

    2010-07-01

    The compression and fatigue behavior of a Ca65Mg15Zn20 bulk-metallic glass (BMG) was studied in air at room temperature. During the preparation of cubical samples of the Ca65Mg15Zn20 for compression and fatigue investigations, small spherical cavities were found. Under both monotonic and cyclic compression loadings of the samples, fractures initiated at these cavities and propagated in a direction generally parallel to the loading axis. Finite-element analysis (FEA) was used to model the fracture behavior. The FEA of a centrally located spherical void showed that under compression loading, large tensile stresses evolved in the cavities. The orientation of the maximum principal stress (P1) was found to be normal to the direction of crack propagation, which is consistent with the experimental finding. Stresses in deeply embedded adjacent voids and those in superficial voids were also studied. The influence of the void location in the cubical sample on the fracture behavior was quantitatively discussed.

  3. Controlling the Vaterite CaCO3 Crystal Pores. Design of Tailor-Made Polymer Based Microcapsules by Hard Templating.

    PubMed

    Feoktistova, Natalia; Rose, Juergen; Prokopović, Vladimir Z; Vikulina, Anna S; Skirtach, Andre; Volodkin, Dmitry

    2016-05-01

    The spherical vaterite CaCO3 microcrystals are nowadays widely used as sacrificial templates for fabrication of various microcarriers made of biopolymers (e.g., proteins, nucleic acids, enzymes) due to porous structure and mild template elimination conditions. Here, we demonstrated for the first time that polymer microcarriers with tuned internal nanoarchitecture can be designed by employing the CaCO3 crystals of controlled porosity. The layer-by-layer deposition has been utilized to assemble shell-like (hollow) and matrix-like (filled) polymer capsules due to restricted and free polymer diffusion through the crystal pores, respectively. The crystal pore size in the range of few tens of nanometers can be adjusted without any additives by variation of the crystal preparation temperature in the range 7-45 °C. The temperature-mediated growth mechanism is explained by the Ostwald ripening of nanocrystallites forming the crystal secondary structure. Various techniques including SEM, AFM, CLSM, Raman microscopy, nitrogen adsorption-desorption, and XRD have been employed for crystal and microcapsule analysis. A three-dimensional model is introduced to describe the crystal internal structure and predict the pore cutoff and available surface for the pore diffusing molecules. Inherent biocompatibility of CaCO3 and a possibility to scale the porosity in the size range of typical biomacromolecules make the CaCO3 crystals extremely attractive tools for template assisted designing tailor-made biopolymer-based architectures in 2D to 3D targeted at drug delivery and other bioapplications. PMID:27052835

  4. CaO--P2O5--Na2O-based sintering additives for hydroxyapatite (HAp) ceramics.

    PubMed

    Kalita, S J; Bose, S; Hosick, H L; Bandyopadhyay, A

    2004-05-01

    We have assessed the effect of CaO--P2O5--Na2O-based sintering additives on mechanical and biological properties of hydroxyapatite (HAp) ceramics. Five different compositions of sintering additives were selected and prepared by mixing of CaO, P2O5, and Na2CO3 powders. 2.5 wt% of each additive was combined with commercial HAp powder, separately, followed by ball milling, and sintering at 1250 degrees C and 1300 degrees C in a muffle furnace. Green and sintered densities of the compacts were analyzed for the influence of additives on densification of HAp. Phase analyses were carried out using an X-ray diffractometer. Vickers microhardness testing was used to evaluate hardness of sintered compacts of different compositions. A maximum microhardness of 4.6 (+/- 0.28) GPa was attained for a composition with 2.5 wt% addition of CaO:P2O5:Na2O in the ratio of 3:3:4. Results from mechanical property evaluation showed that some of these sintering additives improved failure strength of HAp under compressive loading. Maximum compressive strength was observed for samples with 2.5 wt% addition of CaO. Average failure strength for this set of samples was calculated to be 220 (+/- 50) MPa. Cytotoxicity, and cell attachment studies were carried out using a modified human osteoblast cell line called OPC-1. In vitro results showed that these compositions were non-toxic. Some sintering aids enhanced cell attachment and proliferation, which was revealed from SEM examination of the scaffolds seeded with OPC-1 cells. PMID:14741598

  5. Wastewater characterization survey, Edwards Air Force Base, California. Final report, 17-28 February 1992

    SciTech Connect

    McCoy, R.P.

    1992-08-01

    A wastewater characterization survey was conducted at Edwards Air Force Base from 17-28 February 1992 by personnel from the Water Quality Function of Armstrong Laboratory. Extensive sampling of the treatment plant influent wastewater and sludge beds was performed as well as sampling at nine other sites in the base cantonment area. Some sampling of an Imhoff tank on North Base, five evaporation ponds and the lakebed was also conducted. Low levels of organic contamination were found in the influent and industrial sites downstream of Site 7. Site 7 is a manhole located in an identified Installation Restoration Program (IRP) site. Corrective actions were recommended to prevent organic soil contaminants from intruding into this site prior to the operation of a planned tertiary treatment plant. Organic and inorganic contaminants discharged at other industrial sites were found to be in low concentrations and indicated that good shop practices were followed in minimizing contamination of the wastewater with industrial chemicals.

  6. Nanopipette combined with quartz tuning fork-atomic force microscope for force spectroscopy/microscopy and liquid delivery-based nanofabrication

    SciTech Connect

    An, Sangmin; Lee, Kunyoung; Kim, Bongsu; Noh, Haneol; Kim, Jongwoo; Kwon, Soyoung; Lee, Manhee; Hong, Mun-Heon; Jhe, Wonho

    2014-03-15

    This paper introduces a nanopipette combined with a quartz tuning fork-atomic force microscope system (nanopipette/QTF-AFM), and describes experimental and theoretical investigations of the nanoscale materials used. The system offers several advantages over conventional cantilever-based AFM and QTF-AFM systems, including simple control of the quality factor based on the contact position of the QTF, easy variation of the effective tip diameter, electrical detection, on-demand delivery and patterning of various solutions, and in situ surface characterization after patterning. This tool enables nanoscale liquid delivery and nanofabrication processes without damaging the apex of the tip in various environments, and also offers force spectroscopy and microscopy capabilities.

  7. Observationally constrained estimates of carbonaceous aerosol radiative forcing.

    PubMed

    Chung, Chul E; Ramanathan, V; Decremer, Damien

    2012-07-17

    Carbonaceous aerosols (CA) emitted by fossil and biomass fuels consist of black carbon (BC), a strong absorber of solar radiation, and organic matter (OM). OM scatters as well as absorbs solar radiation. The absorbing component of OM, which is ignored in most climate models, is referred to as brown carbon (BrC). Model estimates of the global CA radiative forcing range from 0 to 0.7 Wm(-2), to be compared with the Intergovernmental Panel on Climate Change's estimate for the pre-Industrial to the present net radiative forcing of about 1.6 Wm(-2). This study provides a model-independent, observationally based estimate of the CA direct radiative forcing. Ground-based aerosol network data is integrated with field data and satellite-based aerosol observations to provide a decadal (2001 through 2009) global view of the CA optical properties and direct radiative forcing. The estimated global CA direct radiative effect is about 0.75 Wm(-2) (0.5 to 1.0). This study identifies the global importance of BrC, which is shown to contribute about 20% to 550-nm CA solar absorption globally. Because of the inclusion of BrC, the net effect of OM is close to zero and the CA forcing is nearly equal to that of BC. The CA direct radiative forcing is estimated to be about 0.65 (0.5 to about 0.8) Wm(-2), thus comparable to or exceeding that by methane. Caused in part by BrC absorption, CAs have a net warming effect even over open biomass-burning regions in Africa and the Amazon. PMID:22753522

  8. Effect of Ca incorporation on the dielectric nonlinear behavior of (Ba, Ca)TiO3 multi layer ceramic capacitors

    NASA Astrophysics Data System (ADS)

    Yoon, Seok-Hyun; Park, Yunjung; Kim, Chang-Hoon; Kim, Doo-Young

    2014-12-01

    The difference in the dielectric nonlinearity was investigated by contrasting BaTiO3 and (Ba0.925Ca0.075)TiO3 multilayer ceramic capacitors utilizing the first order reversal curve (FORC) distribution based on the Preisach model. Ca incorporation caused a decrease of the dielectric constants in the low field but little differences in the high field region resulting in a steep ac field dependence, which became more significant with the decrease of temperature. Such behavior can be correlated with a decrease of the reversible and an increase of the irreversible FORC distribution near origin by Ca incorporation. These results suggest that Ca incorporation, which is known to cause the asymmetric off-center displacement at Ba-site, has the role of weakly pinning centers that increase the portion of irreversible domain walls that are immobile at low field but can contribute to polarization beyond a threshold field.

  9. Structure and properties of bioactive eutectic glasses based on the Ca3(PO4)2-CaSiO3-CaMg(SiO3)2 system.

    PubMed

    Magallanes-Perdomo, M; De Aza, A H; Sobrados, I; Sanz, J; Pena, P

    2012-02-01

    Taking into account the phase equilibrium relationships within the Ca3(PO4)2-CaSiO3-CaMg(SiO3)2 ternary system, three bioactive glasses with a eutectic composition and analogous amounts of Ca3(PO4)2 (∼40 wt.%) have been prepared. The structure of the glasses was investigated by 31P and 29Si magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy. The glasses exhibited thermal expansion coefficients (50-600 °C) of 11.8-13.3×10(-6) °C(-1), a glass transition temperature of 790-720 °C and a softening temperature of 811-750 °C. The mechanical properties of the glasses were as follows: bending strength ∼100 MPa, Young's modulus 94-83 GPa, Vickers microhardness 7.1-4.1 GPa and toughness 0.8 MPa m1/2. The bioactive properties were discussed in terms of their structure deduced by MAS-NMR spectroscopy and the field strength of the network modifiers (Mg2+ and Ca2+). A knowledge of the glass structure was important in predicting its bioactivity. PMID:22040687

  10. Cell force mapping using a double-sided micropillar array based on the moiré fringe method

    NASA Astrophysics Data System (ADS)

    Zhang, F.; Anderson, S.; Zheng, X.; Roberts, E.; Qiu, Y.; Liao, R.; Zhang, X.

    2014-07-01

    The mapping of traction forces is crucial to understanding the means by which cells regulate their behavior and physiological function to adapt to and communicate with their local microenvironment. To this end, polymeric micropillar arrays have been used for measuring cell traction force. However, the small scale of the micropillar deflections induced by cell traction forces results in highly inefficient force analyses using conventional optical approaches; in many cases, cell forces may be below the limits of detection achieved using conventional microscopy. To address these limitations, the moiré phenomenon has been leveraged as a visualization tool for cell force mapping due to its inherent magnification effect and capacity for whole-field force measurements. This Letter reports an optomechanical cell force sensor, namely, a double-sided micropillar array (DMPA) made of poly(dimethylsiloxane), on which one side is employed to support cultured living cells while the opposing side serves as a reference pattern for generating moiré patterns. The distance between the two sides, which is a crucial parameter influencing moiré pattern contrast, is predetermined during fabrication using theoretical calculations based on the Talbot effect that aim to optimize contrast. Herein, double-sided micropillar arrays were validated by mapping mouse embryo fibroblast contraction forces and the resulting force maps compared to conventional microscopy image analyses as the reference standard. The DMPA-based approach precludes the requirement for aligning two independent periodic substrates, improves moiré contrast, and enables efficient moiré pattern generation. Furthermore, the double-sided structure readily allows for the integration of moiré-based cell force mapping into microfabricated cell culture environments or lab-on-a-chip devices.

  11. Ab Initio Protein Structure Assembly Using Continuous Structure Fragments and Optimized Knowledge-based Force Field

    PubMed Central

    Xu, Dong; Zhang, Yang

    2012-01-01

    Ab initio protein folding is one of the major unsolved problems in computational biology due to the difficulties in force field design and conformational search. We developed a novel program, QUARK, for template-free protein structure prediction. Query sequences are first broken into fragments of 1–20 residues where multiple fragment structures are retrieved at each position from unrelated experimental structures. Full-length structure models are then assembled from fragments using replica-exchange Monte Carlo simulations, which are guided by a composite knowledge-based force field. A number of novel energy terms and Monte Carlo movements are introduced and the particular contributions to enhancing the efficiency of both force field and search engine are analyzed in detail. QUARK prediction procedure is depicted and tested on the structure modeling of 145 non-homologous proteins. Although no global templates are used and all fragments from experimental structures with template modeling score (TM-score) >0.5 are excluded, QUARK can successfully construct 3D models of correct folds in 1/3 cases of short proteins up to 100 residues. In the ninth community-wide Critical Assessment of protein Structure Prediction (CASP9) experiment, QUARK server outperformed the second and third best servers by 18% and 47% based on the cumulative Z-score of global distance test-total (GDT-TS) scores in the free modeling (FM) category. Although ab initio protein folding remains a significant challenge, these data demonstrate new progress towards the solution of the most important problem in the field. PMID:22411565

  12. Surface modification of alignment layer by ultraviolet irradiation to dramatically improve the detection limit of liquid-crystal-based immunoassay for the cancer biomarker CA125.

    PubMed

    Su, Hui-Wen; Lee, Mon-Juan; Lee, Wei

    2015-05-01

    Liquid crystal (LC)-based biosensing has attracted much attention in recent years. We focus on improving the detection limit of LC-based immunoassay techniques by surface modification of the surfactant alignment layer consisting of dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (DMOAP). The cancer biomarker CA125 was detected with an array of anti-CA125 antibodies immobilized on the ultraviolet (UV)-modified DMOAP monolayer. Compared with a pristine counterpart, UV irradiation enhanced the binding affinity of the CA125 antibody and reproducibility of immunodetection in which a detection limit of 0.01 ng∕ml for the cancer biomarker CA125 was achieved. Additionally, the optical texture observed under a crossed polarized microscope was correlated with the analyte concentration. In a proof-of-concept experiment using CA125-spiked human serum as the analyte, specific binding between the CA125 antigen and the anti-CA125 antibody resulted in a distinct and concentration-dependent optical response despite the high background caused by nonspecific binding of other biomolecules in the human serum. Results from this study indicate that UVmodification of the alignment layer, as well as detection with LCs of large birefringence, contributes to the enhanced performance of the label-free LC-based immunodetection, which may be considered a promising alternative to conventional label-based methods. PMID:26000796

  13. Surface modification of alignment layer by ultraviolet irradiation to dramatically improve the detection limit of liquid-crystal-based immunoassay for the cancer biomarker CA125

    NASA Astrophysics Data System (ADS)

    Su, Hui-Wen; Lee, Mon-Juan; Lee, Wei

    2015-05-01

    Liquid crystal (LC)-based biosensing has attracted much attention in recent years. We focus on improving the detection limit of LC-based immunoassay techniques by surface modification of the surfactant alignment layer consisting of dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (DMOAP). The cancer biomarker CA125 was detected with an array of anti-CA125 antibodies immobilized on the ultraviolet (UV)-modified DMOAP monolayer. Compared with a pristine counterpart, UV irradiation enhanced the binding affinity of the CA125 antibody and reproducibility of immunodetection in which a detection limit of 0.01 ng/ml for the cancer biomarker CA125 was achieved. Additionally, the optical texture observed under a crossed polarized microscope was correlated with the analyte concentration. In a proof-of-concept experiment using CA125-spiked human serum as the analyte, specific binding between the CA125 antigen and the anti-CA125 antibody resulted in a distinct and concentration-dependent optical response despite the high background caused by nonspecific binding of other biomolecules in the human serum. Results from this study indicate that UV modification of the alignment layer, as well as detection with LCs of large birefringence, contributes to the enhanced performance of the label-free LC-based immunodetection, which may be considered a promising alternative to conventional label-based methods.

  14. Feature Selection and Predictors of Falls with Foot Force Sensors Using KNN-Based Algorithms

    PubMed Central

    Liang, Shengyun; Ning, Yunkun; Li, Huiqi; Wang, Lei; Mei, Zhanyong; Ma, Yingnan; Zhao, Guoru

    2015-01-01

    The aging process may lead to the degradation of lower extremity function in the elderly population, which can restrict their daily quality of life and gradually increase the fall risk. We aimed to determine whether objective measures of physical function could predict subsequent falls. Ground reaction force (GRF) data, which was quantified by sample entropy, was collected by foot force sensors. Thirty eight subjects (23 fallers and 15 non-fallers) participated in functional movement tests, including walking and sit-to-stand (STS). A feature selection algorithm was used to select relevant features to classify the elderly into two groups: at risk and not at risk of falling down, for three KNN-based classifiers: local mean-based k-nearest neighbor (LMKNN), pseudo nearest neighbor (PNN), local mean pseudo nearest neighbor (LMPNN) classification. We compared classification performances, and achieved the best results with LMPNN, with sensitivity, specificity and accuracy all 100%. Moreover, a subset of GRFs was significantly different between the two groups via Wilcoxon rank sum test, which is compatible with the classification results. This method could potentially be used by non-experts to monitor balance and the risk of falling down in the elderly population. PMID:26610503

  15. A Statistical Method of Identifying Interactions in Neuron–Glia Systems Based on Functional Multicell Ca2+ Imaging

    PubMed Central

    Nakae, Ken; Ikegaya, Yuji; Ishikawa, Tomoe; Oba, Shigeyuki; Urakubo, Hidetoshi; Koyama, Masanori; Ishii, Shin

    2014-01-01

    Crosstalk between neurons and glia may constitute a significant part of information processing in the brain. We present a novel method of statistically identifying interactions in a neuron–glia network. We attempted to identify neuron–glia interactions from neuronal and glial activities via maximum-a-posteriori (MAP)-based parameter estimation by developing a generalized linear model (GLM) of a neuron–glia network. The interactions in our interest included functional connectivity and response functions. We evaluated the cross-validated likelihood of GLMs that resulted from the addition or removal of connections to confirm the existence of specific neuron-to-glia or glia-to-neuron connections. We only accepted addition or removal when the modification improved the cross-validated likelihood. We applied the method to a high-throughput, multicellular in vitro Ca2+ imaging dataset obtained from the CA3 region of a rat hippocampus, and then evaluated the reliability of connectivity estimates using a statistical test based on a surrogate method. Our findings based on the estimated connectivity were in good agreement with currently available physiological knowledge, suggesting our method can elucidate undiscovered functions of neuron–glia systems. PMID:25393874

  16. American Recovery and Reinvestment Act (ARRA) Federal Energy Management Program Technical Assistance Project 224 Altus Air Force Base Solar Technologies

    SciTech Connect

    Russo, Bryan J.

    2010-09-30

    The principal goal of this project was to evaluate altus Air Force Base for building integrated silicon or thin film module photovoltaic opportunities. This report documents PNNL's efforts and documents study conclusions.

  17. 1. Credit USAF, ca. 1942. Original housed in the Muroc ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Credit USAF, ca. 1942. Original housed in the Muroc Flight Test Base, Unit History, 1 September 1942 - 30 June 1945. Alfred F. Simpson Historical Research Agency. United States Air Force. Maxwell AFB, Alabama. Historical view looks west southwest at construction of Building 4317, Deluge Water Pumping Station (then designated Pump House No. 3). This in-ground structure houses fire pumps which draw water from an in-ground reservoir, Building 4316 (See HAER photos CA-170-I). Pumping station was built in-ground to take advantage of gravity, since water flows from reservoir to prime the pumps, and fire system piping is underground. Opening in far wall is to stairs leading up to ground level. Earth mound in background is part of water reservoir construction (Building 4316). - Edwards Air Force Base, North Base, Deluge Water Pumping Station, Near Second & D Streets, Boron, Kern County, CA

  18. Measurement-based modeling of contact forces and textures for haptic rendering.

    PubMed

    Lang, Jochen; Andrews, Sheldon

    2011-03-01

    Haptic texture represents the fine-grained attributes of an object's surface and is related to physical characteristics such as roughness and stiffness. We introduce an interactive and mobile scanning system for the acquisition and synthesis of haptic textures that consists of a visually tracked handheld touch probe. The most novel aspect of our work is an estimation method for the contact stiffness of an object based solely on the acceleration and forces measured during stroking of its surface with the handheld probe. We establish an experimental relationship between the estimated stiffness and the contact stiffness observed during compression. We also measure the height-displacement profile of an object's surface enabling us to generate haptic textures. We show an example of mapping the textures on to a coarse surface mesh obtained with an image-based technique, but the textures may also be combined with coarse surface meshes obtained by manual modeling. PMID:21233518

  19. Eielson Air Force Base operable unit 2 and other areas record of decision

    SciTech Connect

    Lewis, R.E.; Smith, R.M.

    1994-10-01

    This decision document presents the selected remedial actions and no action decisions for Operable Unit 2 (OU2) at Eielson Air Force Base (AFB), Alaska, chosen in accordance with state and federal regulations. This document also presents the decision that no further action is required for 21 other source areas at Eielson AFB. This decision is based on the administrative record file for this site. OU2 addresses sites contaminated by leaks and spills of fuels. Soils contaminated with petroleum products occur at or near the source of contamination. Contaminated subsurface soil and groundwater occur in plumes on the top of a shallow groundwater table that fluctuates seasonally. These sites pose a risk to human health and the environment because of ingestion, inhalation, and dermal contact with contaminated groundwater. The purpose of this response is to prevent current or future exposure to the contaminated groundwater, to reduce further contaminant migration into the groundwater, and to remediate groundwater.

  20. A vorticity-free approach to wake-based swimming/flying force estimation

    NASA Astrophysics Data System (ADS)

    Dabiri, John O.; Peng, Jifeng

    2006-11-01

    Traditional wake-based analyses of animal swimming and flying depend largely on knowledge of the vorticity field, which can be difficult or impossible to incorporate in the context of unsteady fluid-structure interactions. This talk will describe the development and application of a technique for estimating swimming/flying forces that does not require measurement of the vorticity field. The method is based on the identification of Lagrangian Coherent Structures in the wake, whose dynamics are governed by the theory for deformable bodies in potential flow (Peng and Dabiri, J. Exp. Biol. 2007). This paradigm for the analysis of unsteady fluid-structure interactions is integrated with existing DPIV measurement techniques to analyze medusan (jellyfish) swimming and the dynamics of the bluegill sunfish pectoral fin.

  1. All-atom polarizable force field for DNA based on the classical Drude oscillator model.

    PubMed

    Savelyev, Alexey; MacKerell, Alexander D

    2014-06-15

    Presented is a first generation atomistic force field (FF) for DNA in which electronic polarization is modeled based on the classical Drude oscillator formalism. The DNA model is based on parameters for small molecules representative of nucleic acids, including alkanes, ethers, dimethylphosphate, and the nucleic acid bases and empirical adjustment of key dihedral parameters associated with the phosphodiester backbone, glycosidic linkages, and sugar moiety of DNA. Our optimization strategy is based on achieving a compromise between satisfying the properties of the underlying model compounds in the gas phase targeting quantum mechanical (QM) data and reproducing a number of experimental properties of DNA duplexes in the condensed phase. The resulting Drude FF yields stable DNA duplexes on the 100-ns time scale and satisfactorily reproduce (1) the equilibrium between A and B forms of DNA and (2) transitions between the BI and BII substates of B form DNA. Consistency with the gas phase QM data for the model compounds is significantly better for the Drude model as compared to the CHARMM36 additive FF, which is suggested to be due to the improved response of the model to changes in the environment associated with the explicit inclusion of polarizability. Analysis of dipole moments associated with the nucleic acid bases shows the Drude model to have significantly larger values than those present in CHARMM36, with the dipoles of individual bases undergoing significant variations during the MD simulations. Additionally, the dipole moment of water was observed to be perturbed in the grooves of DNA. PMID:24752978

  2. caTissue Suite to OpenSpecimen: Developing an extensible, open source, web-based biobanking management system.

    PubMed

    McIntosh, Leslie D; Sharma, Mukesh K; Mulvihill, David; Gupta, Snehil; Juehne, Anthony; George, Bijoy; Khot, Suhas B; Kaushal, Atul; Watson, Mark A; Nagarajan, Rakesh

    2015-10-01

    The National Cancer Institute (NCI) Cancer Biomedical Informatics Grid® (caBIG®) program established standards and best practices for biorepository data management by creating an infrastructure to propagate biospecimen resource sharing while maintaining data integrity and security. caTissue Suite, a biospecimen data management software tool, has evolved from this effort. More recently, the caTissue Suite continues to evolve as an open source initiative known as OpenSpecimen. The essential functionality of OpenSpecimen includes the capture and representation of highly granular, hierarchically-structured data for biospecimen processing, quality assurance, tracking, and annotation. Ideal for multi-user and multi-site biorepository environments, OpenSpecimen permits role-based access to specific sets of data operations through a user-interface designed to accommodate varying workflows and unique user needs. The software is interoperable, both syntactically and semantically, with an array of other bioinformatics tools given its integration of standard vocabularies thus enabling research involving biospecimens. End-users are encouraged to share their day-to-day experiences in working with the application, thus providing to the community board insight into the needs and limitations which need be addressed. Users are also requested to review and validate new features through group testing environments and mock screens. Through this user interaction, application flexibility and interoperability have been recognized as necessary developmental focuses essential for accommodating diverse adoption scenarios and biobanking workflows to catalyze advances in biomedical research and operations. Given the diversity of biobanking practices and workforce roles, efforts have been made consistently to maintain robust data granularity while aiding user accessibility, data discoverability, and security within and across applications by providing a lower learning curve in using Open

  3. Computational ligand-based rational design: Role of conformational sampling and force fields in model development

    PubMed Central

    Shim, Jihyun; MacKerell, Alexander D.

    2011-01-01

    A significant number of drug discovery efforts are based on natural products or high throughput screens from which compounds showing potential therapeutic effects are identified without knowledge of the target molecule or its 3D structure. In such cases computational ligand-based drug design (LBDD) can accelerate the drug discovery processes. LBDD is a general approach to elucidate the relationship of a compound's structure and physicochemical attributes to its biological activity. The resulting structure-activity relationship (SAR) may then act as the basis for the prediction of compounds with improved biological attributes. LBDD methods range from pharmacophore models identifying essential features of ligands responsible for their activity, quantitative structure-activity relationships (QSAR) yielding quantitative estimates of activities based on physiochemical properties, and to similarity searching, which explores compounds with similar properties as well as various combinations of the above. A number of recent LBDD approaches involve the use of multiple conformations of the ligands being studied. One of the basic components to generate multiple conformations in LBDD is molecular mechanics (MM), which apply an empirical energy function to relate conformation to energies and forces. The collection of conformations for ligands is then combined with functional data using methods ranging from regression analysis to neural networks, from which the SAR is determined. Accordingly, for effective application of LBDD for SAR determinations it is important that the compounds be accurately modelled such that the appropriate range of conformations accessible to the ligands is identified. Such accurate modelling is largely based on use of the appropriate empirical force field for the molecules being investigated and the approaches used to generate the conformations. The present chapter includes a brief overview of currently used SAR methods in LBDD followed by a more

  4. Computational ligand-based rational design: Role of conformational sampling and force fields in model development.

    PubMed

    Shim, Jihyun; Mackerell, Alexander D

    2011-05-01

    A significant number of drug discovery efforts are based on natural products or high throughput screens from which compounds showing potential therapeutic effects are identified without knowledge of the target molecule or its 3D structure. In such cases computational ligand-based drug design (LBDD) can accelerate the drug discovery processes. LBDD is a general approach to elucidate the relationship of a compound's structure and physicochemical attributes to its biological activity. The resulting structure-activity relationship (SAR) may then act as the basis for the prediction of compounds with improved biological attributes. LBDD methods range from pharmacophore models identifying essential features of ligands responsible for their activity, quantitative structure-activity relationships (QSAR) yielding quantitative estimates of activities based on physiochemical properties, and to similarity searching, which explores compounds with similar properties as well as various combinations of the above. A number of recent LBDD approaches involve the use of multiple conformations of the ligands being studied. One of the basic components to generate multiple conformations in LBDD is molecular mechanics (MM), which apply an empirical energy function to relate conformation to energies and forces. The collection of conformations for ligands is then combined with functional data using methods ranging from regression analysis to neural networks, from which the SAR is determined. Accordingly, for effective application of LBDD for SAR determinations it is important that the compounds be accurately modelled such that the appropriate range of conformations accessible to the ligands is identified. Such accurate modelling is largely based on use of the appropriate empirical force field for the molecules being investigated and the approaches used to generate the conformations. The present chapter includes a brief overview of currently used SAR methods in LBDD followed by a more

  5. Exploring the impact of forcing error characteristics on physically based snow simulations within a global sensitivity analysis framework

    NASA Astrophysics Data System (ADS)

    Raleigh, M. S.; Lundquist, J. D.; Clark, M. P.

    2015-07-01

    Physically based models provide insights into key hydrologic processes but are associated with uncertainties due to deficiencies in forcing data, model parameters, and model structure. Forcing uncertainty is enhanced in snow-affected catchments, where weather stations are scarce and prone to measurement errors, and meteorological variables exhibit high variability. Hence, there is limited understanding of how forcing error characteristics affect simulations of cold region hydrology and which error characteristics are most important. Here we employ global sensitivity analysis to explore how (1) different error types (i.e., bias, random errors), (2) different error probability distributions, and (3) different error magnitudes influence physically based simulations of four snow variables (snow water equivalent, ablation rates, snow disappearance, and sublimation). We use the Sobol' global sensitivity analysis, which is typically used for model parameters but adapted here for testing model sensitivity to coexisting errors in all forcings. We quantify the Utah Energy Balance model's sensitivity to forcing errors with 1 840 000 Monte Carlo simulations across four sites and five different scenarios. Model outputs were (1) consistently more sensitive to forcing biases than random errors, (2) generally less sensitive to forcing error distributions, and (3) critically sensitive to different forcings depending on the relative magnitude of errors. For typical error magnitudes found in areas with drifting snow, precipitation bias was the most important factor for snow water equivalent, ablation rates, and snow disappearance timing, but other forcings had a more dominant impact when precipitation uncertainty was due solely to gauge undercatch. Additionally, the relative importance of forcing errors depended on the model output of interest. Sensitivity analysis can reveal which forcing error characteristics matter most for hydrologic modeling.

  6. 19. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. Photographic copy of photograph (ca. 1962, original print in possession of Peter Kiewit Sons' Co., Omaha, Nebraska) Photographer unknown. Road signs for Alpha Flight Launch Facility sites 8-11 and Bravo Flight Launch Facility sites 2 and 11 - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  7. 33. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    33. Photographic copy of photograph (ca. 1962, original print in possession of Army Corps of Engineers, Ft. Belvoir, Virginia) Photographer unknown. Aerial view of launch control facility under construction, parking area and approach road completed, sewage lagoon at lower right - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  8. 21. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. Photographic copy of photograph (ca. 1962, original print in possession of Army Corps of Engineers, Ft. Belvoir, Virginia) Photographer unknown. View of beginning preparation of reinforcing steel for egg of launch control center - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  9. 26. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    26. Photographic copy of photograph (ca. 1962, original print in possession of Peter Kiewit Sons' Co., Omaha, Nebraska) Photographer unknown. View of egg of launch control center and elevator shaft, forms still in place - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  10. 23. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. Photographic copy of photograph (ca. 1962, original print in possession of Peter Kiewit Sons' Co., Omaha, Nebraska) Photographer unknown. View of reinforcing steel for egg of launch control center - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  11. 22. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. Photographic copy of photograph (ca. 1962, original print in possession of Army Corps of Engineers, Ft. Belvoir, Virginia) Photographer unknown. View of concrete forms for egg of launch control center - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  12. 25. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    25. Photographic copy of photograph (ca. 1962, original print in possession of Peter Kiewit Sons' Co., Omaha, Nebraska) Photographer unknown. View of reinforcing steel and forms for egg of launch control center, showing vents - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  13. 29. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    29. Photographic copy of photograph (ca. 1962, original print in possession of Peter Kiewit Sons' Co., Omaha, Nebraska) Photographer unknown. View of egg of launch control center and elevator shaft, forms removed - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  14. 30. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    30. Photographic copy of photograph (ca. 1962, original print in possession of Peter Kiewit Sons' Co., Omaha, Nebraska) Photographer unknown. View of egg of launch control center and elevator shaft, vents installed - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  15. 27. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. Photographic copy of photograph (ca. 1962, original print in possession of Peter Kiewit Sons' Co., Omaha, Nebraska) Photographer unknown. View of passage from elevator shaft to egg of launch control center - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  16. 24. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. Photographic copy of photograph (ca. 1962, original print in possession of Peter Kiewit Sons' Co., Omaha, Nebraska) Photographer unknown. View of reinforcing steel and forms for egg of launch control center - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  17. 20. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. Photographic copy of photograph (ca. 1962, original print in possession of Peter Kiewit Sons' Co., Omaha, Nebraska) Photographer unknown. View of bed preparation for concrete "egg" of launch control center - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  18. 31. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. Photographic copy of photograph (ca. 1962, original print in possession of Army Corps of Engineers, Ft. Belvoir, Virginia) Photographer unknown. Aerial view of egg of launch control center, nearly buried - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  19. 40. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    40. Photographic copy of photograph (ca. 1962, original print in possession of Peter Kiewit Sons' Co., Omaha, Nebraska) Photographer unknown. View of top of launch facility, preparation of launch closure apron at left - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  20. 36. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    36. Photographic copy of photograph (ca. 1962, original print in possession of Peter Kiewit Sons' Co., Omaha, Nebraska) Photographer unknown. View of launch tube form work inserted into ground - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  1. 28. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. Photographic copy of photograph (ca. 1962, original print in possession of Army Corps of Engineers, Ft. Belvoir, Virginia) Photographer unknown. View of interior of launch control center - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  2. 42. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    42. Photographic copy of photograph (ca. 1962, original print in possession of Peter Kiewit Sons' Co., Omaha, Nebraska) Photographer unknown. View of top of launch facility, installation of launch closure - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  3. 37. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    37. Photographic copy of photograph (ca. 1962, original print in possession of Peter Kiewit Sons' Co., Omaha, Nebraska) Photographer unknown. View of reinforcing steel, top of launch facility - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  4. 39. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    39. Photographic copy of photograph (ca. 1962, original print in possession of Peter Kiewit Sons' Co., Omaha, Nebraska) Photographer unknown. View of top of launch facility, launch support building at right - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  5. 35. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    35. Photographic copy of photograph (ca. 1962, original print in possession of Peter Kiewit Sons' Co., Omaha, Nebraska) Photographer unknown. View of launch tube form work - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  6. 43. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    43. Photographic copy of photograph (ca. 1962, original print in possession of Peter Kiewit Sons' Co., Omaha, Nebraska) Photographer unknown. View of launch closure, launch closure apron at left, personnel access hatch open at right - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  7. 44. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    44. Photographic copy of photograph (ca. 1962, original print in possession of Peter Kiewit Sons' Co., Omaha, Nebraska) Photographer unknown. View of top of launch facility, pouring concrete launch closure - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  8. 32. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    32. Photographic copy of photograph (ca. 1962, original print in possession of Army Corps of Engineers, Ft. Belvoir, Virginia) Photographer unknown. Aerial view of launch control facility under construction - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  9. 38. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    38. Photographic copy of photograph (ca. 1962, original print in possession of Peter Kiewit Sons' Co., Omaha, Nebraska) Photographer unknown. View of reinforcing steel, top of launch facility - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  10. 41. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    41. Photographic copy of photograph (ca. 1962, original print in possession of Peter Kiewit Sons' Co., Omaha, Nebraska) Photographer unknown. View of top of launch facility, preparation of launch closure apron at left - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  11. 34. Photographic copy of photograph (ca. 1962, original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    34. Photographic copy of photograph (ca. 1962, original print in possession of Army Corps of Engineers, Ft. Belvoir, Virginia) Photographer unknown. View of launch control facility under construction, security gate at left - Ellsworth Air Force Base, Delta Flight, 10 mile radius around Exit 127 off Interstate 90, Interior, Jackson County, SD

  12. The Polarizable Atomic Multipole-based AMOEBA Force Field for Proteins

    PubMed Central

    Shi, Yue; Xia, Zhen; Zhang, Jiajing; Best, Robert; Wu, Chuanjie; Ponder, Jay W.; Ren, Pengyu

    2013-01-01

    Development of the AMOEBA (Atomic Multipole Optimized Energetics for Biomolecular Simulation) force field for proteins is presented. The current version (AMOEBA-2013) utilizes permanent electrostatic multipole moments through the quadrupole at each atom, and explicitly treats polarization effects in various chemical and physical environments. The atomic multipole electrostatic parameters for each amino acid residue type are derived from high-level gas phase quantum mechanical calculations via a consistent and extensible protocol. Molecular polarizability is modeled via a Thole-style damped interactive induction model based upon distributed atomic polarizabilities. Inter- and intramolecular polarization is treated in a consistent fashion via the Thole model. The intramolecular polarization model ensures transferability of electrostatic parameters among different conformations, as demonstrated by the agreement between QM and AMOEBA electrostatic potentials, and dipole moments of dipeptides. The backbone and side chain torsional parameters were determined by comparing to gas-phase QM (RI-TRIM MP2/CBS) conformational energies of dipeptides and to statistical distributions from the Protein Data Bank. Molecular dynamics simulations are reported for short peptides in explicit water to examine their conformational properties in solution. Overall the calculated conformational free energies and J-coupling constants are consistent with PDB statistics and experimental NMR results, respectively. In addition, the experimental crystal structures of a number of proteins are well maintained during molecular dynamics (MD) simulation. While further calculations are necessary to fully validate the force field, initial results suggest the AMOEBA polarizable multipole force field is able to describe the structure and energetics of peptides and proteins, in both gas-phase and solution environments. PMID:24163642

  13. Coral Sr/Ca-based sea surface temperature and air temperature variability from the inshore and offshore corals in the Seribu Islands, Indonesia.

    PubMed

    Cahyarini, Sri Yudawati; Zinke, Jens; Troelstra, Simon; Suharsono; Aldrian, Edvin; Hoeksema, B W

    2016-09-30

    The ability of massive Porites corals to faithfully record temperature is assessed. Porites corals from Kepulauan Seribu were sampled from one inshore and one offshore site and analyzed for their Sr/Ca variation. The results show that Sr/Ca of the offshore coral tracked SST, while Sr/Ca variation of the inshore coral tracked ambient air temperature. In particular, the inshore SST variation is related to air temperature anomalies of the urban center of Jakarta. The latter we relate to air-sea interactions modifying inshore SST associated with the land-sea breeze mechanism and/or monsoonal circulation. The correlation pattern of monthly coral Sr/Ca with the Niño3.4 index and SEIO-SST reveals that corals in the Seribu islands region respond differently to remote forcing. An opposite response is observed for inshore and offshore corals in response to El Niño onset, yet similar to El Niño mature phase (December to February). SEIO SSTs co-vary strongly with SST and air temperature variability across the Seribu island reef complex. The results of this study clearly indicate that locations of coral proxy record in Indonesia need to be chosen carefully in order to identify the seasonal climate response to local and remote climate and anthropogenic forcing. PMID:27181035

  14. Real-time deflection and friction force imaging by bimorph-based resonance-type high-speed scanning force microscopy in the contact mode

    NASA Astrophysics Data System (ADS)

    Cai, Wei; Fan, Haiyun; Zhao, Jianyong; Shang, Guangyi

    2014-12-01

    We report herein an alternative high-speed scanning force microscopy method in the contact mode based on a resonance-type piezoelectric bimorph scanner. The experimental setup, the modified optical beam deflection scheme suitable for smaller cantilevers, and a high-speed control program for simultaneous data capture are described in detail. The feature of the method is that the deflection and friction force images of the sample surface can be obtained simultaneously in real time. Images of various samples (e.g., a test grating, a thin gold film, and fluorine-doped tin oxide-coated glass slides) are acquired successfully. The imaging rate is 25 frames per second, and the average scan speed reaches a value of approximately 2.5 cm/s. The method combines the advantages of both observing the dynamic processes of the sample surface and monitoring the frictional properties on the nanometer scale.

  15. The study on the atomic force microscopy base nanoscale electrical discharge machining.

    PubMed

    Huang, Jen-Ching; Chen, Chung-Ming

    2012-01-01

    This study proposes an innovative atomic force microscopy (AFM) based nanoscale electrical discharge machining (AFM-based nanoEDM) system which combines an AFM with a self-produced metallic probe and a high-voltage generator to create an atmospheric environment AFM-based nanoEDM system and a deionized water (DI water) environment AFM-based nanoEDM system. This study combines wire-cut processing and electrochemical tip sharpening techniques on a 40-µm thick stainless steel sheet to produce a high conductive AFM probes, the production can withstand high voltage and large current. The tip radius of these probes is approximately 40 nm. A probe test was executed on the AFM using probes to obtain nanoscales morphology of Si wafer surface. The silicon wafer was as a specimen to carry out AFM-base nanoEDM process in atmospheric and DI water environments by AFM-based nanoEDM system. After experiments, the results show that the atmospheric and DI water environment AFM-based nanoEDM systems operate smoothly. From experimental results, it can be found that the electric discharge depth of the silicon wafer at atmospheric environments is a mere 14.54 nm. In a DI water environment, the depth of electric discharge of the silicon wafer can reach 25.4 nm. This indicates that the EDM ability of DI water environment AFM-based nanoEDM system is higher than that of atmospheric environment AFM-based nanoEDM system. After multiple nanoEDM process, the tips become blunt. After applying electrochemical tip sharpening techniques, the tip radius can return to approximately 40 nm. Therefore, AFM probes produced in this study can be reused. PMID:21898457

  16. Immunoassays for the cancer biomarker CA125 based on a large-birefringence nematic liquid-crystal mixture.

    PubMed

    Sun, Shih-Hung; Lee, Mon-Juan; Lee, Yun-Han; Lee, Wei; Song, Xiaolong; Chen, Chao-Yuan

    2015-01-01

    The use of fluorescence is ubiquitously found in the detection of immunoreaction; though with good sensitivity, this technique requires labeling as well as other time-consuming steps to perform the measurement. An alternative approach involving liquid crystals (LCs) was proposed, based on the fact that an immunocomplex can disturb the orientation of LCs, leading to an optical texture different from the case when only antigen or antibody exists. This method is label-free, easy to manipulate and low-cost. However, its sensitivity was low for practical usage. In this study, we adopted a high-birefringence liquid crystal (LC) to enhance the sensitivity for the immunodetection. Experiments were performed, targeting at the cancer biomarker CA125. We showed that the larger birefringence (Δn = 0.33 at 20 °C) amplifies the detected signal and, in turn, dramatically improves the detection limit. To avoid signal loss from conventional rinsing steps in immunodetection, CA125 antigen and antibody were reacted before immobilized on substrates. We studied the specific binding events and obtained a detection limit as low as 1 ng/ml. The valid temperature ranges were compared by using the typical single-compound LC 5CB and the high-birefringence LC mixture. We further investigated time dependency of the optical textures and affirmed the capability of LC-based immunodetection in distinguishing between specific and nonspecific antibodies. PMID:25657889

  17. Immunoassays for the cancer biomarker CA125 based on a large-birefringence nematic liquid-crystal mixture

    PubMed Central

    Sun, Shih-Hung; Lee, Mon-Juan; Lee, Yun-Han; Lee, Wei; Song, Xiaolong; Chen, Chao-Yuan

    2014-01-01

    The use of fluorescence is ubiquitously found in the detection of immunoreaction; though with good sensitivity, this technique requires labeling as well as other time-consuming steps to perform the measurement. An alternative approach involving liquid crystals (LCs) was proposed, based on the fact that an immunocomplex can disturb the orientation of LCs, leading to an optical texture different from the case when only antigen or antibody exists. This method is label-free, easy to manipulate and low-cost. However, its sensitivity was low for practical usage. In this study, we adopted a high-birefringence liquid crystal (LC) to enhance the sensitivity for the immunodetection. Experiments were performed, targeting at the cancer biomarker CA125. We showed that the larger birefringence (Δn = 0.33 at 20 °C) amplifies the detected signal and, in turn, dramatically improves the detection limit. To avoid signal loss from conventional rinsing steps in immunodetection, CA125 antigen and antibody were reacted before immobilized on substrates. We studied the specific binding events and obtained a detection limit as low as 1 ng/ml. The valid temperature ranges were compared by using the typical single-compound LC 5CB and the high-birefringence LC mixture. We further investigated time dependency of the optical textures and affirmed the capability of LC-based immunodetection in distinguishing between specific and nonspecific antibodies. PMID:25657889

  18. (Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio)

    SciTech Connect

    Not Available

    1991-10-01

    In April 1990, Wright-Patterson Air Force Base (WPAFB) initiated an effort for the evaluation of potential removal of ground water contamination at the Base. This report presents a current assessment of the nature and extent of the contamination believed to be migrating across the southwestern boundary of Area C and the northern boundary of Area B based upon analysis of existing environmental data obtained from several sources. The existing data base indicates widespread, low-level contamination moving across Base boundaries at levels that pose no immediate threat to the Mad River Valley well fields. An investigation by the City of Dayton in May and June 1990, however, implies that a more identifiable plume of PCE and TCE may be crossing the southwestern boundary of Area C immediately downgradient of Landfill 5. More data is needed to delineate ground water contamination and to design and implement a suitable control system. This report concludes that although an extensive study of the boundaries in question would be the preferred approach, a limited, focused investigation and subsequent feasibility study can be accomplished with a reasonable certainty of achieving the desired outcome of this project.

  19. Potential overflow of Mojave Creek near disposal site, Edwards Air Force Base, California

    USGS Publications Warehouse

    Dinehart, Randy L.; Harmon, Jerry G.

    1998-01-01

    Sedimentological evidence in Mojave Creek near Edwards, California, indicates that the largest discharge in the last hundred years near the disposal site of the Main Base Landfill at Edwards Air Force Base was a few hundred cubic feet per second. The distal ends of two alluvial fans on the Mojave Creek floodplain near the Main Base Landfill have not been eroded substantially since sediment supply was cut off by a railroad grade completed in 1884. Previous estimates of flood discharges were 4,000 cubic feet per second and larger in this reach; the estimates were calculated by regression equations derived from regional characteristics. However, a 100-year rainfall in 1983 failed to produce erosion in Mojave Creek commensurate with discharges of greater than about 100 cubic feet per second. To test the potential for the creek to overflow and reach the disposal site, a hypothetical discharge was used to determine the depth of flooding at local cross sections. Although the access road from Mojave Boulevard to the Main Base Landfill may be inundated during a flood, the artificial grade at the disposal site would not be reached at a discharge of 2,000 cubic feet per second, which is an order of magnitude greater than the apparent flood discharges that occurred during the past hundred years in Mojave Creek near the present Main Base Landfill.

  20. 19. Photographic copy of construction drawing, F.E. Warren Air Force ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. Photographic copy of construction drawing, F.E. Warren Air Force Base Installation Office, ca. 1955 (original print located at F.E. Warren Air Force Base Archives, Cheyenne, Wyoming). SOUTH AND WEST ELEVATIONS. - Fort David A. Russell, Gymnasium, Randall Avenue between Fourth & Fifth Streets, Cheyenne, Laramie County, WY