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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 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

  10. 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

  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. 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

  16. 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

  17. 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

  18. 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

  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, Civil Engineering Storage Building, 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, Microwave Equipment 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, Electric Substation, 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. 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

  17. 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

  18. 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...

  19. 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.

  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. 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

  11. 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

  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. 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

  8. 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.

  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. 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

  15. 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

  16. 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

  17. 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

  18. 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.

  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. 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

  8. 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.

  9. 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.

  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. 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.

  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. 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

  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. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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...

  12. 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...

  13. 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...

  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. 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

  16. 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

  17. 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

  18. 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

  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. 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…

  4. 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

  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. 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

  12. 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

  13. 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.

  14. 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...

  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. 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

  17. 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

  18. 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

  19. 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

  20. 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

  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. 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

  8. 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

  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. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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.

  18. 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.

  19. 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.

  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. 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

  9. 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

  10. 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.

  11. 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

  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. 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

  2. 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...

  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 ...

  4. 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...

  5. (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.

  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