Sample records for nanoelectromechanical system nems

  1. Carbon Nanotube Based Nano-Electro-Mechanical Systems (NEMS)

    NASA Technical Reports Server (NTRS)

    Han, Jie; Dai, Hongjie; Saini, Subhash

    1998-01-01

    Carbon nanotubes (CNT) enable nanoelectromechanical systems (NEMS) because of their inherent nanostructure, intrinsic electric conductivity and mechanical resilience. The collaborative work between Stanford (experiment) and NASA Ames (theory and simulation) has made progress in two types of CNT based NEMS for nanoelectronics and sensor applications. The CNT tipped scanning probe microscopy (SPM) is a NEMS in which CNT tips are used for nanoscale probing, imaging and manipulating. It showed great improvement in probing surfaces and biological systems over conventional tips. We have recently applied it to write (lithography) and read (image) uniform SiO2 lines on large Si surface area at speed up to 0.5 mm per s. Preliminary work using approximately 10 nm multiwall nanotube tips produced approximately 10 nm structures and showed that the CNT tips didn't wear down when crashed as conventional tips often do. This presents a solution to the long standing tip-wear problem in SPM nanolithography. We have also explored potential of CNT tips in imaging DNA in water. Preliminary experiment using 10 nm CNT tips reached 5 nm resolution. The 1 nm nanolithography and 1 nm DNA imaging can be expected by using approximately 1 nm CNT tips. In contrast to CNT tipped SPM, we also fabricated CNT devices on silicon wafer in which CNTs connect patterned metallic lines on SiO2/Si by a simple chemical vapor deposition process. Using conventional lithography for silicon wafer, we have been able to obtain CNT based transistors and sensors. Investigations of the CNT NEMS as physical, biological and chemical sensors are in progress and will be discussed.

  2. Nano-Electro-Mechanical (NEM) Relay Devices and Technology for Ultra-Low Energy Digital Integrated Circuits

    DTIC Science & Technology

    2013-05-01

    number. 1. REPORT DATE 01 MAY 2013 2. REPORT TYPE 3. DATES COVERED 00-00- 2013 to 00-00- 2013 4. TITLE AND SUBTITLE Nano-Electro-Mechanical (NEM...18 Copyright © 2013 , by the author( s ). All rights reserved. Permission to make digital or hard copies of all or part of this work for personal or...E. Ismail, S .-H. Lo, G. A. Sai- Halasz, R . G. Viswanathan, H.-J. C. Wann, S . J. Wind, and H.- S . Wong, “CMOS scaling into the nanometer regime

  3. A single active nanoelectromechanical tuning fork front-end radio-frequency receiver

    NASA Astrophysics Data System (ADS)

    Bartsch, Sebastian T.; Rusu, A.; Ionescu, Adrian M.

    2012-06-01

    Nanoelectromechanical systems (NEMS) offer the potential to revolutionize fundamental methods employed for signal processing in today’s telecommunication systems, owing to their spectral purity and the prospect of integration with existing technology. In this work we present a novel, front-end receiver topology based on a single device silicon nanoelectromechanical mixer-filter. The operation is demonstrated by using the signal amplification in a field effect transistor (FET) merged into a tuning fork resonator. The combination of both a transistor and a mechanical element into a hybrid unit enables on-chip functionality and performance previously unachievable in silicon. Signal mixing, filtering and demodulation are experimentally demonstrated at very high frequencies ( > 100 MHz), maintaining a high quality factor of Q = 800 and stable operation at near ambient pressure (0.1 atm) and room temperature (T = 300 K). The results show that, ultimately miniaturized, silicon NEMS can be utilized to realize multi-band, single-chip receiver systems based on NEMS mixer-filter arrays with reduced system complexity and power consumption.

  4. Neutral Mass Spectrometry of Mega-Dalton Particles with Single-Particle Resolution using a Nano-Electromechanical System

    NASA Astrophysics Data System (ADS)

    Kelber, Scott; Hanay, Mehmet; Naik, Akshay; Chi, Derrick; Hentz, Sebastien; Bullard, Caryn; Collinet, Eric; Duraffourg, Laurent; Roukes, Michael

    2012-02-01

    Nanoelectromechanical systems (NEMS) enable mass sensing with unprecedented sensitivity and mass dynamic range. Previous works have relied on statistical analysis of multiple landing events to assemble mass spectra. Here we demonstrate the utility of using multiple modes of the NEMS device in determining the mass of individual molecules landing on the NEMS. Analyte particles in vapor form are produced using matrix assisted laser desorption ionization. Resonant frequencies of the first two modes of a single NEMS device, placed in close proximity to the analyte source, are tracked using parallel phase locked loops. Each analyte molecule landing on the NEMS generates a distinct frequency shift in the two modes. These time correlated frequency jumps are used to evaluate the mass of each analyte particle landing on the NEMS and thus generate mass spectra. We present the latest experimental results using this scheme and also demonstrate the utility for mass spectrometry of large biomolecules. This NEMS-Mass Spec. system offers a new tool for structural biology and pathology for the analysis of large proteins, protein complexes, and viruses.

  5. Ultra low power consumption for self-oscillating nanoelectromechanical systems constructed by contacting two nanowires.

    PubMed

    Barois, T; Ayari, A; Vincent, P; Perisanu, S; Poncharal, P; Purcell, S T

    2013-04-10

    We report here the observation of a new self-oscillation mechanism in nanoelectromechanical systems (NEMS). A highly resistive nanowire was positioned to form a point-contact at a chosen vibration node of a silicon carbide nanowire resonator. Spontaneous and robust mechanical oscillations arise when a sufficient DC voltage is applied between the two nanowires. An original model predicting the threshold voltage is used to estimate the piezoresistivity of the point-contact in agreement with the observations. The measured input power is in the pW-range which is the lowest reported value for such systems. The simplicity of the contacting procedure and the low power consumption open a new route for integrable and low-loss self-excited NEMS devices.

  6. Resonant micro and nanoelectromechanical systems: Actuation and biological sensing studies

    NASA Astrophysics Data System (ADS)

    Ilic, Bojan

    This thesis explores various actuation mechanisms of resonant nanoelectro-mechanical systems (NEMS) with emphasis directed towards detection of biomolecules. Arrays of bulk and surface micromachined devices, made using conventional thin film fabrication methods, are used to explore the mass loading effects of selective molecular immobilization on the surface of the NEMS resonators. Experimentally measured shift in the first eigenfrequency is correlated to the amount of mass loading from the binding events and verified using theoretical constructs. Under ambient conditions where considerable damping occurs, immunospecific detection of single Escherichia coli O157:H7 cells is demonstrated by measuring the out of plane vibrational resonant mode using an optical deflection system with thermal noise as an excitation mechanism. Further sensitivity enhancement utilizing vacuum encapsulation in conjunction with piezoelectric actuation and tailoring of the cantilever dimensions is demonstrated by measuring mass loading of a nonpathogenic insect baculovirus, single Aminopropyltriethoxysilane (APTS), Hexamethyldisilazane (HMDS) and Octade-cyltrichlorosilane (OTS) monolayers. To highlight the lower detectable mass limit, surface machined NEMS oscillators with integrated circular Au contacts and sub-attogram mass detection sensitivity are used for selective immobilization of dinitrophenyl poly(ethylene glycol) undecanthiol based molecules. Experimental and theoretical elucidation of optical actuation of NEMS cantilevers at large distances from the clamped end is presented. These observations are considered within the theoretical framework of heat transfer and used to measure binding events of single double-stranded deoxyribonucleic acid (dsDNA) molecules to localized gold nanodots near the free end of a NEMS oscillator. Because this method allows direct coupling of energy into the device layer, several modes of in-plane vibrations are observed and employed in shaking off

  7. Thermoelastic Damping in FGM Nano-Electromechanical System in Axial Vibration Based on Eringen Nonlocal Theory

    NASA Astrophysics Data System (ADS)

    Rahimi, Z.; Rashahmadi, S.

    2017-11-01

    The thermo-elastic damping is a dominant source of internal damping in micro-electromechanical systems (MEMS) and nano-electromechanical systems (NEMS). The internal damping cannot neither be controlled nor minimized unless either mechanical or geometrical properties are changed. Therefore, a novel FGMNEM system with a controllable thermo-elastic damping of axial vibration based on Eringen nonlocal theory is considered. The effects of different parameter like the gradient index, nonlocal parameter, length of nanobeam and ambient temperature on the thermo-elastic damping quality factor are presented. It is shown that the thermo-elastic damping can be controlled by changing different parameter.

  8. Attosecond nanotechnology: NEMS of energy storage and nanostructural transformations in materials

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Beznosyuk, Sergey A., E-mail: bsa1953@mail.ru; Maslova, Olga A., E-mail: maslova-o.a@mail.ru; Zhukovsky, Mark S., E-mail: zhukovsky@list.ru

    2015-10-27

    The attosecond technology of the nanoelectromechanical system (NEMS) energy storage as active center fast transformation of nanostructures in materials is considered. The self-organizing relaxation of the NEMS active center containing nanocube of 256-atoms limited by planes (100) in the FCC lattice matrix of 4d-transition metals (Ru, Rh, Pd) is described by the quantum NEMS-kinetics (NK) method. Typical for these metals change of the NEMS active center physicochemical characteristics during the time of relaxation is presented. There are three types of intermediate quasistationary states of the NEMS active center. Their forms are plainly distinguishable. The full relaxed NEMS active centers (Ru{submore » 256}, Rh{sub 256}, Pd{sub 256}) accumulate next storage energies: E{sub Ru} = 2.27 eV/at, E{sub Rh} = 1.67 eV/at, E{sub Pd} = 3.02 eV/at.« less

  9. Lead zirconate titanate nanoscale patterning by ultraviolet-based lithography lift-off technique for nano-electromechanical system applications.

    PubMed

    Guillon, Samuel; Saya, Daisuke; Mazenq, Laurent; Costecalde, Jean; Rèmiens, Denis; Soyer, Caroline; Nicu, Liviu

    2012-09-01

    The advantage of using lead zirconate titanate (PbZr(0.54)Ti(0.46)O(3)) ceramics as an active material in nanoelectromechanical systems (NEMS) comes from its relatively high piezoelectric coefficients. However, its integration within a technological process is limited by the difficulty of structuring this material with submicrometer resolution at the wafer scale. In this work, we develop a specific patterning method based on optical lithography coupled with a dual-layer resist process. The main objective is to obtain sub-micrometer features by lifting off a 100-nm-thick PZT layer while preserving the material's piezoelectric properties. A subsequent result of the developed method is the ability to stack several layers with a lateral resolution of few tens of nanometers, which is mandatory for the fabrication of NEMS with integrated actuation and read-out capabilities.

  10. Electromechanical control of nitrogen-vacancy defect emission using graphene NEMS

    PubMed Central

    Reserbat-Plantey, Antoine; Schädler, Kevin G.; Gaudreau, Louis; Navickaite, Gabriele; Güttinger, Johannes; Chang, Darrick; Toninelli, Costanza; Bachtold, Adrian; Koppens, Frank H. L.

    2016-01-01

    Despite recent progress in nano-optomechanics, active control of optical fields at the nanoscale has not been achieved with an on-chip nano-electromechanical system (NEMS) thus far. Here we present a new type of hybrid system, consisting of an on-chip graphene NEMS suspended a few tens of nanometres above nitrogen-vacancy centres (NVCs), which are stable single-photon emitters embedded in nanodiamonds. Electromechanical control of the photons emitted by the NVC is provided by electrostatic tuning of the graphene NEMS position, which is transduced to a modulation of NVC emission intensity. The optomechanical coupling between the graphene displacement and the NVC emission is based on near-field dipole–dipole interaction. This class of optomechanical coupling increases strongly for smaller distances, making it suitable for nanoscale devices. These achievements hold promise for selective control of emitter arrays on-chip, optical spectroscopy of individual nano-objects, integrated optomechanical information processing and open new avenues towards quantum optomechanics. PMID:26742541

  11. Nanoelectromechanical systems: Nanodevice motion at microwave frequencies

    NASA Astrophysics Data System (ADS)

    Henry Huang, Xue Ming; Zorman, Christian A.; Mehregany, Mehran; Roukes, Michael L.

    2003-01-01

    It has been almost forgotten that the first computers envisaged by Charles Babbage in the early 1800s were mechanical and not electronic, but the development of high-frequency nanoelectromechanical systems is now promising a range of new applications, including sensitive mechanical charge detectors and mechanical devices for high-frequency signal processing, biological imaging and quantum measurement. Here we describe the construction of nanodevices that will operate with fundamental frequencies in the previously inaccessible microwave range (greater than 1 gigahertz). This achievement represents a significant advance in the quest for extremely high-frequency nanoelectromechanical systems.

  12. On-chip optical transduction scheme for graphene nano-electro-mechanical systems in silicon-photonic platform

    NASA Astrophysics Data System (ADS)

    Dash, Aneesh; Selvaraja, S. K.; Naik, A. K.

    2018-02-01

    We present a scheme for on-chip optical transduction of strain and displacement of Graphene-based Nano-Electro-Mechanical Systems (NEMS). A detailed numerical study on the feasibility of three silicon-photonic integrated circuit configurations is presented: Mach-Zehnder Interferometer(MZI), micro-ring resonator and ring-loaded MZI. An index-sensing based technique using a Mach-Zehnder Interferometer loaded with a ring resonator with a moderate Q-factor of 2400 can yield a sensitivity of 28 fm/sqrt(Hz), and 6.5E-6 %/sqrt(Hz) for displacement and strain respectively. Though any phase sensitive integrated photonic device could be used for optical transduction, here we show that optimal sensitivity is achievable by combining resonance with phase sensitivity.

  13. FOREWORD: Focus on Novel Nanoelectromechanical 3D Structures: Fabrication and Properties Focus on Novel Nanoelectromechanical 3D Structures: Fabrication and Properties

    NASA Astrophysics Data System (ADS)

    Yamada, Shooji; Yamaguchi, Hiroshi; Ishihara, Sunao

    2009-06-01

    Microelectromechanical systems (MEMS) are widely used small electromechanical systems made of micrometre-sized components. Presently, we are witnessing a transition from MEMS to nanoelectromechanical systems (NEMS), which comprise devices integrating electrical and mechanical functionality on the nanoscale and offer new exciting applications. Similarly to MEMS, NEMS typically include a central transistor-like nanoelectronic unit for data processing, as well as mechanical actuators, pumps, and motors; and they may combine with physical, biological and chemical sensors. In the transition from MEMS to NEMS, component sizes need to be reduced. Therefore, many fabrication methods previously developed for MEMS are unsuitable for the production of high-precision NEMS components. The key challenge in NEMS is therefore the development of new methods for routine and reproducible nanofabrication. Two complementary types of method for NEMS fabrication are available: 'top-down' and 'bottom-up'. The top-down approach uses traditional lithography technologies, whereas bottom-up techniques include molecular self-organization, self-assembly and nanodeposition. The NT2008 conference, held at Ishikawa High-Tech Conference Center, Ishikawa, Japan, between 23-25 October 2008, focused on novel NEMS fabricated from new materials and on process technologies. The topics included compound semiconductors, small mechanical structures, nanostructures for micro-fluid and bio-sensors, bio-hybrid micro-machines, as well as their design and simulation. This focus issue compiles seven articles selected from 13 submitted manuscripts. The articles by Prinz et al and Kehrbusch et al introduce the frontiers of the top-down production of various operational NEMS devices, and Kometani et al present an example of the bottom-up approach, namely ion-beam induced deposition of MEMS and NEMS. The remaining articles report novel technologies for biological sensors. Taira et al have used manganese nanoparticles

  14. Nano-electromechanical switch-CMOS hybrid technology and its applications.

    PubMed

    Lee, B H; Hwang, H J; Cho, C H; Lim, S K; Lee, S Y; Hwang, H

    2011-01-01

    Si-based CMOS technology is facing a serious challenge in terms of power consumption and variability. The increasing costs associated with physical scaling have motivated a search for alternative approaches. Hybridization of nano-electromechanical (NEM)-switch and Si-based CMOS devices has shown a theoretical feasibility for power management, but a huge technical gap must be bridged before a nanoscale NEM switch can be realized due to insufficient material development and the limited understanding of its reliability characteristics. These authors propose the use of a multilayer graphene as a nanoscale cantilever material for a nanoscale NEM switchwith dimensions comparable to those of the state-of-the-art Si-based CMOS devices. The optimal thickness for the multilayer graphene (about five layers) is suggested based on an analytical model. Multilayer graphene can provide the highest Young's modulus among the known electrode materials and a yielding strength that allows more than 15% bending. Further research on material screening and device integration is needed, however, to realize the promises of the hybridization of NEM-switch and Si-based CMOS devices.

  15. On-chip optical transduction scheme for graphene nano-electro-mechanical systems in silicon-photonic platform.

    PubMed

    Dash, Aneesh; Selvaraja, S K; Naik, A K

    2018-02-15

    We present a scheme for on-chip optical transduction of strain and displacement of graphene-based nano-electro-mechanical systems (NEMS). A detailed numerical study on the feasibility of three silicon-photonic integrated circuit configurations is presented: the Mach-Zehnder interferometer (MZI), the micro-ring resonator, and the ring-loaded MZI. An index sensing based technique using an MZI loaded with a ring resonator with a moderate Q-factor of 2400 can yield a sensitivity of 28  fm/Hz and 6.5×10 -6 %/Hz for displacement and strain, respectively. Though any phase-sensitive integrated-photonic device could be used for optical transduction, here we show that optimal sensitivity is achievable by combining resonance with phase sensitivity.

  16. VHF NEMS-CMOS piezoresistive resonators for advanced sensing applications

    NASA Astrophysics Data System (ADS)

    Arcamone, Julien; Dupré, Cécilia; Arndt, Grégory; Colinet, Eric; Hentz, Sébastien; Ollier, Eric; Duraffourg, Laurent

    2014-10-01

    This work reports on top-down nanoelectromechanical resonators, which are among the smallest resonators listed in the literature. To overcome the fact that their electromechanical transduction is intrinsically very challenging due to their very high frequency (100 MHz) and ultimate size (each resonator is a 1.2 μm long, 100 nm wide, 20 nm thick silicon beam with 100 nm long and 30 nm wide piezoresistive lateral nanowire gauges), they have been monolithically integrated with an advanced fully depleted SOI CMOS technology. By advantageously combining the unique benefits of nanomechanics and nanoelectronics, this hybrid NEMS-CMOS device paves the way for novel breakthrough applications, such as NEMS-based mass spectrometry or hybrid NEMS/CMOS logic, which cannot be fully implemented without this association.

  17. Self-Biased 215MHz Magnetoelectric NEMS Resonator for Ultra-Sensitive DC Magnetic Field Detection

    NASA Astrophysics Data System (ADS)

    Nan, Tianxiang; Hui, Yu; Rinaldi, Matteo; Sun, Nian X.

    2013-06-01

    High sensitivity magnetoelectric sensors with their electromechanical resonance frequencies < 200 kHz have been recently demonstrated using magnetostrictive/piezoelectric magnetoelectric heterostructures. In this work, we demonstrate a novel magnetoelectric nano-electromechanical systems (NEMS) resonator with an electromechanical resonance frequency of 215 MHz based on an AlN/(FeGaB/Al2O3) × 10 magnetoelectric heterostructure for detecting DC magnetic fields. This magnetoelectric NEMS resonator showed a high quality factor of 735, and strong magnetoelectric coupling with a large voltage tunable sensitivity. The admittance of the magnetoelectric NEMS resonator was very sensitive to DC magnetic fields at its electromechanical resonance, which led to a new detection mechanism for ultra-sensitive self-biased RF NEMS magnetoelectric sensor with a low limit of detection of DC magnetic fields of ~300 picoTelsa. The magnetic/piezoelectric heterostructure based RF NEMS magnetoelectric sensor is compact, power efficient and readily integrated with CMOS technology, which represents a new class of ultra-sensitive magnetometers for DC and low frequency AC magnetic fields.

  18. Constructing biomolecular motor-powered hybrid NEMS devices

    NASA Astrophysics Data System (ADS)

    Bachand, George D.; Montemagno, Carlo D.

    1999-10-01

    The recognition of many enzymes as nanoscale molecular motors has allowed for the potential creation of hybrid organic/inorganic nano-electro-mechanical (NEMS) devices. The long-range goal of this research is the integration of F1-ATPase with NEMS to produce useful nanoscale devices. A thermostable F1-ATPase coding sequence has been isolated, cloned, and engineered for high-level protein expression. Precise positioning, spacing, and orientation of single F1-ATPase molecules were achieved using patterned nickel arrays. An efficient, accurate, and adaptable assay was developed to assess the performance of single F1- ATPase motors, and confirmed a three-step mechanism of (gamma) subunit rotation during ATP hydrolysis. Further evaluation of the bioengineering and biophysical properties of F1-ATPase currently are being conducted, as well as the construction of an F1-ATPase-powered, hybrid NEMS device. The evolution of this technology will permit the creation of novel classes of nanoscale, hybrid devices.

  19. Review: Electrostatically actuated nanobeam-based nanoelectromechanical switches – materials solutions and operational conditions

    PubMed Central

    Jasulaneca, Liga; Kosmaca, Jelena; Meija, Raimonds; Andzane, Jana

    2018-01-01

    This review summarizes relevant research in the field of electrostatically actuated nanobeam-based nanoelectromechanical (NEM) switches. The main switch architectures and structural elements are briefly described and compared. Investigation methods that allow for exploring coupled electromechanical interactions as well as studies of mechanically or electrically induced effects are covered. An examination of the complex nanocontact behaviour during various stages of the switching cycle is provided. The choice of the switching element and the electrode is addressed from the materials perspective, detailing the benefits and drawbacks for each. An overview of experimentally demonstrated NEM switching devices is provided, and together with their operational parameters, the reliability issues and impact of the operating environment are discussed. Finally, the most common NEM switch failure modes and the physical mechanisms behind them are reviewed and solutions proposed. PMID:29441272

  20. Nanoelectromechanical digital logic circuits using curved cantilever switches with amorphous-carbon-coated contacts

    NASA Astrophysics Data System (ADS)

    Ayala, Christopher L.; Grogg, Daniel; Bazigos, Antonios; Bleiker, Simon J.; Fernandez-Bolaños, Montserrat; Niklaus, Frank; Hagleitner, Christoph

    2015-11-01

    Nanoelectromechanical (NEM) switches have the potential to complement or replace traditional CMOS transistors in the area of ultra-low-power digital electronics. This paper reports the demonstration of prototype circuits including the first 3-stage ring oscillator built using cell-level digital logic elements based on curved NEM switches. The ring oscillator core occupies an area of 30 μm × 10 μm using 6 NEM switches. Each NEM switch device has a footprint of 5 μm × 3 μm, an air gap of 60 μm and is coated with amorphous carbon (a-C) for reliable operation. The ring oscillator operates at a frequency of 6.7 MHz, and confirms the simulated inverter propagation delay of 25 ns. The successful fabrication and measurement of this demonstrator are key milestones on the way towards an optimized, scaled technology with sub-nanosecond switching times, lower operating voltages and VLSI implementation.

  1. Noise in nonlinear nanoelectromechanical resonators

    NASA Astrophysics Data System (ADS)

    Guerra Vidal, Diego N.

    Nano-Electro-Mechanical Systems (NEMS), due to their nanometer scale size, possess a number of desirable attributes: high sensitivity to applied forces, fast response times, high resonance frequencies and low power consumption. However, ultra small size and low power handling result in unwanted consequences: smaller signal size and higher dissipation, making the NEMS devices more susceptible to external and intrinsic noise. The simplest version of a NEMS, a suspended nanomechanical structure with two distinct excitation states, can be used as an archetypal two state system to study a plethora of fundamental phenomena such as Duffing nonlinearity, stochastic resonance, and macroscopic quantum tunneling at low temperatures. From a technical perspective, there are numerous applications such nanomechanical memory elements, microwave switches and nanomechanical computation. The control and manipulation of the mechanical response of these two state systems can be realized by exploiting a (seemingly) counterintuitive physical phenomenon, Stochastic Resonance: in a noisy nonlinear mechanical system, the presence of noise can enhance the system response to an external stimulus. This Thesis is mainly dedicated to study possible applications of Stochastic Resonance in two-state nanomechanical systems. First, on chip signal amplification by 1/falpha is observed. The effectiveness of the noise assisted amplification is observed to decrease with increasing a. Experimental evidence shows an increase in asymmetry between the two states with increasing noise color. Considering the prevalence of 1/f alpha noise in the materials in integrated circuits, the signal enhancement demonstrated here, suggests beneficial use of the otherwise detrimental noise. Finally, a nanomechanical device, operating as a reprogrammable logic gate, and performing fundamental logic functions such as AND/OR and NAND/NOR is presented. The logic function can be programmed (from AND to OR) dynamically, by

  2. Energy efficient circuit design using nanoelectromechanical relays

    NASA Astrophysics Data System (ADS)

    Venkatasubramanian, Ramakrishnan

    Nano-electromechanical (NEM) relays are a promising class of emerging devices that offer zero off-state leakage and behave like an ideal switch. Recent advances in planar fabrication technology have demonstrated that microelectromechanical (MEMS) scale miniature relays could be manufactured reliably and could be used to build fully functional, complex integrated circuits. The zero leakage operation of relays has renewed the interest in relay based low power logic design. This dissertation explores circuit architectures using NEM relays and NEMS-CMOS heterogeneous integration. Novel circuit topologies for sequential logic, memory, and power management circuits have been proposed taking into consideration the NEM relay device properties and optimizing for energy efficiency and area. In nanoscale electromechanical devices, dispersion forces like Van der Waals' force (vdW) affect the pull-in stability of the relay devices significantly. Verilog-A electromechanical model of the suspended gate relay operating at 1V with a nominal air gap of 5 - 10nm has been developed taking into account all the electrical, mechanical and dispersion effects. This dissertation explores different relay based latch and flip-flop topologies. It has been shown that as few as 4 relay cells could be used to build flip-flops. An integrated voltage doubler based flip flop that improves the performance by 2X by overdriving Vgb has been proposed. Three NEM relay based parallel readout memory bitcell architectures have been proposed that have faster access time, and remove the reliability issues associated with previously reported serial readout architectures. A paradigm shift in design of power switches using NEM relays is proposed. An interesting property of the relay device is that the ON state resistance (Ron) of the NEM relay switch is constant and is insensitive to the gate slew rate. This coupled with infinite OFF state resistance (Roff ) offers significant area and power advantages over CMOS

  3. Tunneling Nanoelectromechanical Switches Based on Compressible Molecular Thin Films.

    PubMed

    Niroui, Farnaz; Wang, Annie I; Sletten, Ellen M; Song, Yi; Kong, Jing; Yablonovitch, Eli; Swager, Timothy M; Lang, Jeffrey H; Bulović, Vladimir

    2015-08-25

    Abrupt switching behavior and near-zero leakage current of nanoelectromechanical (NEM) switches are advantageous properties through which NEMs can outperform conventional semiconductor electrical switches. To date, however, typical NEMs structures require high actuation voltages and can prematurely fail through permanent adhesion (defined as stiction) of device components. To overcome these challenges, in the present work we propose a NEM switch, termed a "squitch," which is designed to electromechanically modulate the tunneling current through a nanometer-scale gap defined by an organic molecular film sandwiched between two electrodes. When voltage is applied across the electrodes, the generated electrostatic force compresses the sandwiched molecular layer, thereby reducing the tunneling gap and causing an exponential increase in the current through the device. The presence of the molecular layer avoids direct contact of the electrodes during the switching process. Furthermore, as the layer is compressed, the increasing surface adhesion forces are balanced by the elastic restoring force of the deformed molecules which can promote zero net stiction and recoverable switching. Through numerical analysis, we demonstrate the potential of optimizing squitch design to enable large on-off ratios beyond 6 orders of magnitude with operation in the sub-1 V regime and with nanoseconds switching times. Our preliminary experimental results based on metal-molecule-graphene devices suggest the feasibility of the proposed tunneling switching mechanism. With optimization of device design and material engineering, squitches can give rise to a broad range of low-power electronic applications.

  4. NEMS - National Energy Modeling System: An Overview

    EIA Publications

    2009-01-01

    The National Energy Modeling System: An Overview 2009 a summary description of NEMS and each of its components. NEMS is a computer-based, energy-economy modeling system of energy markets for the midterm period through 2030. The NEMS is used to produce the Annual Energy Outlook.

  5. Optical spring effect in nanoelectromechanical systems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tian, Feng; Zhou, Guangya, E-mail: mpezgy@nus.edu.sg; Du, Yu

    2014-08-11

    In this Letter, we report a hybrid system consisting of nano-optical and nano-mechanical springs, in which the optical spring effect works to adjust the mechanical frequency of a nanoelectromechanical systems resonator. Nano-scale folded beams are fabricated as the mechanical springs and double-coupled one-dimensional photonic crystal cavities are used to pump the “optical spring.” The dynamic characteristics of this hybrid system are measured and analyzed at both low and high input optical powers. This study leads the physical phenomenon of optomechanics in complex nano-opto-electro-mechanical systems (NOEMS) and could benefit the future applications of NOEMS in chip-level communication and sensing.

  6. A Low-Voltage and High Uniformity Nano-Electro-Mechanical System Tunable Color Filter Based on Subwavelength Grating

    NASA Astrophysics Data System (ADS)

    Honma, Hiroaki; Takahashi, Kazuhiro; Ishida, Makoto; Sawada, Kazuaki

    2012-11-01

    This paper reports on the construction of a nano-electro-mechanical system (NEMS) tunable color filter based on a subwavelength grating with high color uniformity and a low drive voltage. We recently proposed a ground-voltage-ground (GVG)-type tunable color filter with a parallel-plate actuator with three pairs of electrodes to decrease the crosstalk due to the electrostatic attractive force between each pair of actuators. Our finite element method (FEM) simulation results indicate that the drive voltage is decreased by 10 V, as compared to that of the previously reported GV type. The proposed structure was fabricated using a silicon-on-insulator (SOI) wafer. The color tuning capability of the device was demonstrated by applying a drive voltage of 6.7 V. The reflected light intensity was decreased by 34% at a wavelength of 680 nm. Color uniformity was also obtained in the filter area by reducing the variation of the displacement on the one-dimensional actuator arrays.

  7. Directed growth of horizontally aligned gallium nitride nanowires for nanoelectromechanical resonator arrays.

    PubMed

    Henry, Tania; Kim, Kyungkon; Ren, Zaiyuan; Yerino, Christopher; Han, Jung; Tang, Hong X

    2007-11-01

    We report the growth of horizontally aligned arrays and networks of GaN nanowires (NWs) as resonant components in nanoelectromechanical systems (NEMS). A combination of top-down selective area growth (SAG) and bottom-up vapor-liquid-solid (VLS) synthesis enables flexible fabrication of highly ordered nanowire arrays in situ with no postgrowth dispersion. Mechanical resonance of free-standing nanowires are measured, with quality factors (Q) ranging from 400 to 1000. We obtained a Young's modulus (E) of approximately 338 GPa from an array of NWs with varying diameters and lengths. The measurement allows detection of nanowire motion with a rotating frame and reveals dual fundamental resonant modes in two orthogonal planes. A universal ratio between the resonant frequencies of these two fundamental modes, irrespective of their dimensions, is observed and attributed to an isosceles cross section of GaN NWs.

  8. How to obtain the National Energy Modeling System (NEMS)

    EIA Publications

    2013-01-01

    The National Energy Modeling System (NEMS) NEMS is used by the modelers at the U. S. Energy Information Administration (EIA) who understand its structure and programming. NEMS has only been used by a few organizations outside of the EIA, because most people that requested NEMS found out that it was too difficult or rigid to use. NEMS is not typically used for state-level analysis and is poorly suited for application to other countries. However, many do obtain the model simply to use the data in its input files or to examine the source code.

  9. Dynamics-Enabled Nanoelectromechanical Systems (NEMS) Oscillators

    DTIC Science & Technology

    2014-06-01

    it becomes strongly nonlinear, and thus constitutes an archetypal candidate for nonlinear engineering • its fundamental resonant frequency...width of spectral peaks of atomic force microscopy (AFM) resonators as they are brought close to a surface. 39 Approved for public release...alternating current AD Allan Deviation AFM atomic force microscopy AFRL Air Force Research Laboratory AlN aluminum nitride APN Anomalous Phase

  10. Nanostructured 2D cellular materials in silicon by sidewall transfer lithography NEMS

    NASA Astrophysics Data System (ADS)

    Syms, Richard R. A.; Liu, Dixi; Ahmad, Munir M.

    2017-07-01

    Sidewall transfer lithography (STL) is demonstrated as a method for parallel fabrication of 2D nanostructured cellular solids in single-crystal silicon. The linear mechanical properties of four lattices (perfect and defected diamond; singly and doubly periodic honeycomb) with low effective Young’s moduli and effective Poisson’s ratio ranging from positive to negative are modelled using analytic theory and the matrix stiffness method with an emphasis on boundary effects. The lattices are fabricated with a minimum feature size of 100 nm and an aspect ratio of 40:1 using single- and double-level STL and deep reactive ion etching of bonded silicon-on-insulator. Nanoelectromechanical systems (NEMS) containing cellular materials are used to demonstrate stretching, bending and brittle fracture. Predicted edge effects are observed, theoretical values of Poisson’s ratio are verified and failure patterns are described.

  11. In-situ comprehensive calibration of a tri-port nano-electro-mechanical device.

    PubMed

    Collin, E; Defoort, M; Lulla, K; Moutonet, T; Heron, J-S; Bourgeois, O; Bunkov, Yu M; Godfrin, H

    2012-04-01

    We report on experiments performed in vacuum and at cryogenic temperatures on a tri-port nano-electro-mechanical (NEMS) device. One port is a very nonlinear capacitive actuation, while the two others implement the magnetomotive scheme with a linear input force port and a (quasi-linear) output velocity port. We present an experimental method enabling a full characterization of the nanomechanical device harmonic response: the nonlinear capacitance function C(x) is derived, and the normal parameters k and m (spring constant and mass) of the mode under study are measured through a careful definition of the motion (in meters) and of the applied forces (in Newtons). These results are obtained with a series of purely electric measurements performed without disconnecting/reconnecting the device, and rely only on known dc properties of the circuit, making use of a thermometric property of the oscillator itself: we use the Young modulus of the coating metal as a thermometer, and the resistivity for Joule heating. The setup requires only three connecting lines without any particular matching, enabling the preservation of a high impedance NEMS environment even at MHz frequencies. The experimental data are fit to a detailed electrical and thermal model of the NEMS device, demonstrating a complete understanding of its dynamics. These methods are quite general and can be adapted (as a whole, or in parts) to a large variety of electromechanical devices. © 2012 American Institute of Physics

  12. MEMS- and NEMS-based smart devices and systems

    NASA Astrophysics Data System (ADS)

    Varadan, Vijay K.

    2001-11-01

    The microelectronics industry has seen explosive growth during the last thirty years. Extremely large markets for logic and memory devices have driven the development of new materials, and technologies for the fabrication of even more complex devices with features sized now don at the sub micron and nanometer level. Recent interest has arisen in employing these materials, tools and technologies for the fabrication of miniature sensors and actuators and their integration with electronic circuits to produce smart devices and systems. This effort offers the promise of: 1) increasing the performance and manufacturability of both sensors and actuators by exploiting new batch fabrication processes developed including micro stereo lithographic an micro molding techniques; 2) developing novel classes of materials and mechanical structures not possible previously, such as diamond like carbon, silicon carbide and carbon nanotubes, micro-turbines and micro-engines; 3) development of technologies for the system level and wafer level integration of micro components at the nanometer precision, such as self-assembly techniques and robotic manipulation; 4) development of control and communication systems for MEMS devices, such as optical and RF wireless, and power delivery systems, etc. A novel composite structure can be tailored by functionalizing carbon nano tubes and chemically bonding them with the polymer matrix e.g. block or graft copolymer, or even cross-linked copolymer, to impart exceptional structural, electronic and surface properties. Bio- and Mechanical-MEMS devices derived from this hybrid composite provide a new avenue for future smart systems. The integration of NEMS (NanoElectroMechanical Systems), MEMS, IDTs (Interdigital Transducers) and required microelectronics and conformal antenna in the multifunctional smart materials and composites results in a smart system suitable for sensing and control of a variety functions in automobile, aerospace, marine and civil

  13. nem_spread Ver. 5.10

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    HENNIGAN, GARY; SHADID, JOHN; SJAARDEMA, GREGORY

    2009-06-08

    Nem_spread reads it's input command file (default name nem_spread.inp), takes the named ExodusII geometry definition and spreads out the geometry (and optionally results) contained in that file out to a parallel disk system. The decomposition is taken from a scalar Nemesis load balance file generated by the companion utility nem_slice.

  14. Integrating Module - NEMS Documentation

    EIA Publications

    2014-01-01

    Provides an overview of the complete National Energy Modeling System (NEMS) model, and includes brief descriptions of the modules with which the Integrating Module interacts. The emphasis and focus, however, is on the structure and function of the Integrating Module of NEMS.

  15. Langley's views on NEMS

    NASA Technical Reports Server (NTRS)

    George, J. W.

    1984-01-01

    The views of the Langley Research Center regarding the NASA Equipment Management System (EMS) are discussed. One of Langley's greatest concerns is with the reconciliation between NEMS and the General Ledger. Langley's accounting system tracks cost data to the penny level. NEMS deals in whole dollar amounts. Therefore, Langley has no way of reconciling the two. The only approach that is acceptable to Langley, unless requirements for reconciliation are changed, is for the NEMS files and the reports involved in the process be at the penny level. All other NEMS reports can remain whole dollars. Also to reconcile, Langley needs data to show the difference between the previous cost and the new cost for the month. On an input record, the adjustment amount is added to the cost and recorded as total amount. The adjusted cost is not captured. In order to establish a control between the prior months and the current month, a new field needs to be added to capture the adjusted cost (debits And credits). Langley has not reconciled the Equipment account with the General Ledger since February 1984. Problems with NEMS regular production runs cause concern. Production at Langley is run on the second and/or third shift. If a run(s) terminates and/or abends in a particular module, Langley must wait until the next day to resolve NEMS problems after consultation with Headquarters personnel. For a successful installation, Langley must have a good data base to convert to NEMS and users and the data processing staff must work together.

  16. Development of the physics driver in NOAA Environmental Modeling System (NEMS)

    NASA Astrophysics Data System (ADS)

    Lei, H.; Iredell, M.; Tripp, P.

    2016-12-01

    As a key component of the Next Generation Global Prediction System (NGGPS), a physics driver is developed in the NOAA Environmental Modeling System (NEMS) in order to facilitate the research, development, and transition to operations of innovations in atmospheric physical parameterizations. The physics driver connects the atmospheric dynamic core, the Common Community Physics Package and the other NEMS-based forecast components (land, ocean, sea ice, wave, and space weather). In current global forecasting system, the physics driver has incorporated major existing physics packages including radiation, surface physics, cloud and microphysics, ozone, and stochastic physics. The physics driver is also applicable to external physics packages. The structure adjustment in NEMS by separating the PHYS trunk is to create an open physics package pool. This open platform is beneficial to the enhancement of U.S. weather forecast ability. In addition, with the universal physics driver, the NEMS can also be used for specific functions by connecting external target physics packages through physics driver. The test of its function is to connect a physics dust-radiation model in the system. Then the modified system can be used for dust storm prediction and forecast. The physics driver is also developed into a standalone form. This is to facilitate the development works on physics packages. The developers can save instant fields of meteorology data and snapshots from the running system , and then used them as offline driving data fields to test the new individual physics modules or small modifications to current modules. This prevents the run of whole system for every test.

  17. CMOS compatible thin-film ALD tungsten nanoelectromechanical devices

    NASA Astrophysics Data System (ADS)

    Davidson, Bradley Darren

    This research focuses on the development of a novel, low-temperature, CMOS compatible, atomic-layer-deposition (ALD) enabled NEMS fabrication process for the development of ALD Tungsten (WALD) NEMS devices. The devices are intended for use in CMOS/NEMS hybrid systems, and NEMS based micro-processors/controllers capable of reliable operation in harsh environments not accessible to standard CMOS technologies. The majority of NEMS switches/devices to date have been based on carbon-nano-tube (CNT) designs. The devices consume little power during actuation, and as expected, have demonstrated actuation voltages much smaller than MEMS switches. Unfortunately, NEMS CNT switches are not typically CMOS integrable due to the high temperatures required for their growth, and their fabrication typically results in extremely low and unpredictable yields. Thin-film NEMS devices offer great advantages over reported CNT devices for several reasons, including: higher fabrication yields, low-temperature (CMOS compatible) deposition techniques like ALD, and increased control over design parameters/device performance metrics, i.e., device geometry. Furthermore, top-down, thin-film, nano-fabrication techniques are better capable of producing complicated device geometries than CNT based processes, enabling the design and development of multi-terminal switches well-suited for low-power hybrid NEMS/CMOS systems as well as electromechanical transistors and logic devices for use in temperature/radiation hard computing architectures. In this work several novel, low-temperature, CMOS compatible fabrication technologies, employing WALD as a structural layer for MEMS or NEMS devices, were developed. The technologies developed are top-down nano-scale fabrication processes based on traditional micro-machining techniques commonly used in the fabrication of MEMS devices. Using these processes a variety of novel WALD NEMS devices have been successfully fabricated and characterized. Using two different

  18. Self-sustained oscillations in nanoelectromechanical systems induced by Kondo resonance

    NASA Astrophysics Data System (ADS)

    Song, Taegeun; Kiselev, Mikhail N.; Kikoin, Konstantin; Shekhter, Robert I.; Gorelik, Leonid Y.

    2014-03-01

    We investigate the instability and dynamical properties of nanoelectromechanical systems represented by a single-electron device containing movable quantum dots attached to a vibrating cantilever via asymmetric tunnel contacts. The Kondo resonance in electron tunneling between the source and shuttle facilitates self-sustained oscillations originating from the strong coupling of mechanical and electronic/spin degrees of freedom. We analyze a stability diagram for the two-channel Kondo shuttling regime due to limitations given by the electromotive force acting on a moving shuttle, and find that the saturation oscillation amplitude is associated with the retardation effect of the Kondo cloud. The results shed light on possible ways to experimentally realize the Kondo-cloud dynamical probe by using high mechanical dissipation tunability as well as supersensitive detection of mechanical displacement.

  19. Properties of piezoresistive silicon nano-scale cantilevers with applications to BioNEMS

    NASA Astrophysics Data System (ADS)

    Arlett, Jessica Lynn

    Over the last decade a great deal of interest has been raised in applications of Microelectromechanical Sensors [MEMS] for the detection of biological molecules and to the study of their forces of interaction. Experiments in these areas have included Force Spectroscopy (Chemical Force Microscopy), MEMS patch clamp technology, and surface stress sensors. All of these technologies suffer from limitations on temporal response and involve devices with active surface areas that are large compared to molecular dimensions. Biofunctionalized nanoelectromechanical systems (BioNEMS) have the potential to overcome both of these hurdles, offering important new prospects for single-molecule force assays that are amenable to large scale integration. Results are presented here on the characterization of piezoresistive silicon cantilevers with applications to BioNEMS devices. The cantilevers were characterized by studying their response in gaseous ambients under a number of drive conditions including magnetic, piezoelectric, and thermal actuation, in addition to passive detection of the thermomechanical response. The measurements were performed at liquid helium temperature, at room temperature, and over a range of pressures (atmospheric pressure to 30mT). Theoretical studies have been performed on the response of these devices to Brownian fluctuations in fluid, on the feasibility of these devices as surface stress sensors, and on improvements in device design as compared to piezoresistive surface stress sensors currently discussed in the literature. The devices were encapsulated in microfluidics and measurements were performed to show the noise floor in fluid. The piezoresistive response of the device in fluid was shown through the use of pulsatory fluidic drive. As a proof of concept, biodetection experiments are presented for biotin labeled beads. The biofunctionalization for the latter experiment was performed entirely within the microfluidics. A discussion of how these

  20. Nanotechnology: MEMS and NEMS and their applications to smart systems and devices

    NASA Astrophysics Data System (ADS)

    Varadan, Vijay K.

    2003-10-01

    The microelectronics industry has seen explosive growth during the last thirty years. Extremely large markets for logic and memory devices have driven the development of new materials, and technologies for the fabrication of even more complex devices with features sizes now down at the sub micron and nanometer level. Recent interest has arisen in employing these materials, tools and technologies for the fabrication of miniature sensors and actuators and their integration with electronic circuits to produce smart devices and systems. This effort offers the promise of: (1) increasing the performance and manufacturability of both sensors and actuators by exploiting new batch fabrication processes developed including micro stereo lithographic and micro molding techniques; (2) developing novel classes of materials and mechanical structures not possible previously, such as diamond like carbon, silicon carbide and carbon nanotubes, micro-turbines and micro-engines; (3) development of technologies for the system level and wafer level integration of micro components at the nanometer precision, such as self-assembly techniques and robotic manipulation; (4) development of control and communication systems for MEMS devices, such as optical and RF wireless, and power delivery systems, etc. A novel composite structure can be tailored by functionalizing carbon nano tubes and chemically bonding them with the polymer matrix e.g. block or graft copolymer, or even cross-linked copolymer, to impart exceptional structural, electronic and surface properties. Bio- and Mechanical-MEMS devices derived from this hybrid composite provide a new avenue for future smart systems. The integration of NEMS (NanoElectroMechanical Systems), MEMS, IDTs (Interdigital Transducers) and required microelectronics and conformal antenna in the multifunctional smart materials and composites results in a smart system suitable for sending and control of a variety functions in automobile, aerospace, marine and

  1. Large scale integration of CVD-graphene based NEMS with narrow distribution of resonance parameters

    NASA Astrophysics Data System (ADS)

    Arjmandi-Tash, Hadi; Allain, Adrien; (Vitto Han, Zheng; Bouchiat, Vincent

    2017-06-01

    We present a novel method for the fabrication of the arrays of suspended micron-sized membranes, based on monolayer pulsed-CVD graphene. Such devices are the source of an efficient integration of graphene nano-electro-mechanical resonators, compatible with production at the wafer scale using standard photolithography and processing tools. As the graphene surface is continuously protected by the same polymer layer during the whole process, suspended graphene membranes are clean and free of imperfections such as deposits, wrinkles and tears. Batch fabrication of 100 μm-long multi-connected suspended ribbons is presented. At room temperature, mechanical resonance of electrostatically-actuated devices show narrow distribution of their characteristic parameters with high quality factor and low effective mass and resonance frequencies, as expected for low stress and adsorbate-free membranes. Upon cooling, a sharp increase of both resonant frequency and quality factor is observed, enabling to extract the thermal expansion coefficient of CVD graphene. Comparison with state-of-the-art graphene NEMS is presented.

  2. Design evaluation of graphene nanoribbon nanoelectromechanical devices

    NASA Astrophysics Data System (ADS)

    Lam, Kai-Tak; Stephen Leo, Marie; Lee, Chengkuo; Liang, Gengchiau

    2011-07-01

    Computational studies on nanoelectromechanical switches based on bilayer graphene nanoribbons (BGNRs) with different designs are presented in this work. By varying the interlayer distance via electrostatic means, the conductance of the BGNR can be changed in order to achieve ON-states and OFF-states, thereby mimicking the function of a switch. Two actuator designs based on the modified capacitive parallel plate (CPP) model and the electrostatic repulsive force (ERF) model are discussed for different applications. Although the CPP design provides a simple electrostatic approach to changing the interlayer distance of the BGNR, their switching gate bias VTH strongly depends on the gate area, which poses a limitation on the size of the device. In addition, there exists a risk of device failure due to static fraction between the mobile and fixed electrodes. In contrast, the ERF design can circumvent both issues with a more complex structure. Finally, optimizations of the devices are carried out in order to provide insights into the design considerations of these nanoelectromechanical switches.

  3. Renewable Fuels Module - NEMS Documentation

    EIA Publications

    2017-01-01

    This report documents the objectives, analytical approach, and design of the National Energy Modeling System (NEMS) Renewable Fuels Module (RFM) as it relates to the production of the Annual Energy Outlook forecasts.

  4. Industrial Demand Module - NEMS Documentation

    EIA Publications

    2014-01-01

    Documents the objectives, analytical approach, and development of the National Energy Modeling System (NEMS) Industrial Demand Module. The report catalogues and describes model assumptions, computational methodology, parameter estimation techniques, and model source code.

  5. A triple quantum dot based nano-electromechanical memory device

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pozner, R.; Lifshitz, E.; Solid State Institute, Technion-Israel Institute of Technology, Haifa 32000

    Colloidal quantum dots (CQDs) are free-standing nano-structures with chemically tunable electronic properties. This tunability offers intriguing possibilities for nano-electromechanical devices. In this work, we consider a nano-electromechanical nonvolatile memory (NVM) device incorporating a triple quantum dot (TQD) cluster. The device operation is based on a bias induced motion of a floating quantum dot (FQD) located between two bound quantum dots (BQDs). The mechanical motion is used for switching between two stable states, “ON” and “OFF” states, where ligand-mediated effective interdot forces between the BQDs and the FQD serve to hold the FQD in each stable position under zero bias. Consideringmore » realistic microscopic parameters, our quantum-classical theoretical treatment of the TQD reveals the characteristics of the NVM.« less

  6. Residential Demand Module - NEMS Documentation

    EIA Publications

    2017-01-01

    Model Documentation - Documents the objectives, analytical approach, and development of the National Energy Modeling System (NEMS) Residential Sector Demand Module. The report catalogues and describes the model assumptions, computational methodology, parameter estimation techniques, and FORTRAN source code.

  7. Transportation Sector Module - NEMS Documentation

    EIA Publications

    2017-01-01

    Documents the objectives, analytical approach and development of the National Energy Modeling System (NEMS) Transportation Model (TRAN). The report catalogues and describes the model assumptions, computational methodology, parameter estimation techniques, model source code, and forecast results generated by the model.

  8. Single-protein nanomechanical mass spectrometry in real time

    PubMed Central

    Hanay, M.S.; Kelber, S.; Naik, A.K.; Chi, D.; Hentz, S.; Bullard, E.C.; Colinet, E.; Duraffourg, L.; Roukes, M.L.

    2012-01-01

    Nanoelectromechanical systems (NEMS) resonators can detect mass with exceptional sensitivity. Previously, mass spectra from several hundred adsorption events were assembled in NEMS-based mass spectrometry using statistical analysis. Here, we report the first realization of single-molecule NEMS-based mass spectrometry in real time. As each molecule in the sample adsorbs upon the NEMS resonator, its mass and the position-of-adsorption are determined by continuously tracking two driven vibrational modes of the device. We demonstrate the potential of multimode NEMS-based mass spectrometry by analyzing IgM antibody complexes in real-time. NEMS-MS is a unique and promising new form of mass spectrometry: it can resolve neutral species, provides resolving power that increases markedly for very large masses, and allows acquisition of spectra, molecule-by-molecule, in real-time. PMID:22922541

  9. Macroeconomic Activity Module - NEMS Documentation

    EIA Publications

    2016-01-01

    Documents the objectives, analytical approach, and development of the National Energy Modeling System (NEMS) Macroeconomic Activity Module (MAM) used to develop the Annual Energy Outlook for 2016 (AEO2016). The report catalogues and describes the module assumptions, computations, methodology, parameter estimation techniques, and mainframe source code

  10. Automatic calculation of the nine equivalents of nursing manpower use score (NEMS) using a patient data management system.

    PubMed

    Junger, Axel; Brenck, Florian; Hartmann, Bernd; Klasen, Joachim; Quinzio, Lorenzo; Benson, Matthias; Michel, Achim; Röhrig, Rainer; Hempelmann, Gunter

    2004-07-01

    The most recent approach to estimate nursing resources consumption has led to the generation of the Nine Equivalents of Nursing Manpower use Score (NEMS). The objective of this prospective study was to establish a completely automatically generated calculation of the NEMS using a patient data management system (PDMS) database and to validate this approach by comparing the results with those of the conventional manual method. Prospective study. Operative intensive care unit of a university hospital. Patients admitted to the ICU between 24 July 2002 and 22 August 2002. Patients under the age of 16 years, and patients undergoing cardiovascular surgery or with burn injuries were excluded. None. The NEMS of all patients was calculated automatically with a PDMS and manually by a physician in parallel. The results of the two methods were compared using the Bland and Altman approach, the interclass correlation coefficient (ICC), and the kappa-statistic. On 20 consecutive working days, the NEMS was calculated in 204 cases. The Bland Altman analysis did not show significant differences in NEMS scoring between the two methods. The ICC (95% confidence intervals) 0.87 (0.84-0.90) revealed a high inter-rater agreement between the PDMS and the physician. The kappa-statistic showed good results (kappa>0.55) for all NEMS items apart from the item "supplementary ventilatory care". This study demonstrates that automatical calculation of the NEMS is possible with high accuracy by means of a PDMS. This may lead to a decrease in consumption of nursing resources.

  11. Commercial Demand Module - NEMS Documentation

    EIA Publications

    2017-01-01

    Documents the objectives, analytical approach and development of the National Energy Modeling System (NEMS) Commercial Sector Demand Module. The report catalogues and describes the model assumptions, computational methodology, parameter estimation techniques, model source code, and forecast results generated through the synthesis and scenario development based on these components.

  12. Precise control of coupling strength in photonic molecules over a wide range using nanoelectromechanical systems

    PubMed Central

    Du, Han; Zhang, Xingwang; Chen, Guoqiang; Deng, Jie; Chau, Fook Siong; Zhou, Guangya

    2016-01-01

    Photonic molecules have a range of promising applications including quantum information processing, where precise control of coupling strength is critical. Here, by laterally shifting the center-to-center offset of coupled photonic crystal nanobeam cavities, we demonstrate a method to precisely and dynamically control the coupling strength of photonic molecules through integrated nanoelectromechanical systems with a precision of a few GHz over a range of several THz without modifying the nature of their constituent resonators. Furthermore, the coupling strength can be tuned continuously from negative (strong coupling regime) to zero (weak coupling regime) and further to positive (strong coupling regime) and vice versa. Our work opens a door to the optimization of the coupling strength of photonic molecules in situ for the study of cavity quantum electrodynamics and the development of efficient quantum information devices. PMID:27097883

  13. Self-transducing silicon nanowire electromechanical systems at room temperature.

    PubMed

    He, Rongrui; Feng, X L; Roukes, M L; Yang, Peidong

    2008-06-01

    Electronic readout of the motions of genuinely nanoscale mechanical devices at room temperature imposes an important challenge for the integration and application of nanoelectromechanical systems (NEMS). Here, we report the first experiments on piezoresistively transduced very high frequency Si nanowire (SiNW) resonators with on-chip electronic actuation at room temperature. We have demonstrated that, for very thin (~90 nm down to ~30 nm) SiNWs, their time-varying strain can be exploited for self-transducing the devices' resonant motions at frequencies as high as approximately 100 MHz. The strain of wire elongation, which is only second-order in doubly clamped structures, enables efficient displacement transducer because of the enhanced piezoresistance effect in these SiNWs. This intrinsically integrated transducer is uniquely suited for a class of very thin wires and beams where metallization and multilayer complex patterning on devices become impractical. The 30 nm thin SiNW NEMS offer exceptional mass sensitivities in the subzeptogram range. This demonstration makes it promising to advance toward NEMS sensors based on ultrathin and even molecular-scale SiNWs, and their monolithic integration with microelectronics on the same chip.

  14. Actuation and transduction of resonant vibrations in GaAs/AlGaAs-based nanoelectromechanical systems containing two-dimensional electron gas

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shevyrin, A. A., E-mail: shevandrey@isp.nsc.ru; Pogosov, A. G.; Bakarov, A. K.

    2015-05-04

    Driven vibrations of a nanoelectromechanical system based on GaAs/AlGaAs heterostructure containing two-dimensional electron gas are experimentally investigated. The system represents a conductive cantilever with the free end surrounded by a side gate. We show that out-of-plane flexural vibrations of the cantilever are driven when alternating signal biased by a dc voltage is applied to the in-plane side gate. We demonstrate that these vibrations can be on-chip linearly transduced into a low-frequency electrical signal using the heterodyne down-mixing method. The obtained data indicate that the dominant physical mechanism of the vibrations actuation is capacitive interaction between the cantilever and the gate.

  15. Self-oscillations in field emission nanowire mechanical resonators: a nanometric dc-ac conversion.

    PubMed

    Ayari, Anthony; Vincent, Pascal; Perisanu, Sorin; Choueib, May; Gouttenoire, Vincent; Bechelany, Mikhael; Cornu, David; Purcell, Stephen T

    2007-08-01

    We report the observation of self-oscillations in a bottom-up nanoelectromechanical system (NEMS) during field emission driven by a constant applied voltage. An electromechanical model is explored that explains the phenomenon and that can be directly used to develop integrated devices. In this first study, we have already achieved approximately 50% dc/ac (direct to alternating current) conversion. Electrical self-oscillations in NEMS open up a new path for the development of high-speed, autonomous nanoresonators and signal generators and show that field emission (FE) is a powerful tool for building new nanocomponents.

  16. Coal Market Module - NEMS Documentation

    EIA Publications

    2014-01-01

    Documents the objectives and the conceptual and methodological approach used in the development of the National Energy Modeling System's (NEMS) Coal Market Module (CMM) used to develop the Annual Energy Outlook 2014 (AEO2014). This report catalogues and describes the assumptions, methodology, estimation techniques, and source code of CMM's two submodules. These are the Coal Production Submodule (CPS) and the Coal Distribution Submodule (CDS).

  17. Superharmonic resonances in a two-dimensional non-linear photonic-crystal nano-electro-mechanical oscillator

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chowdhury, A.; Yeo, I.; Tsvirkun, V.

    2016-04-18

    We investigate the non-linear mechanical dynamics of a nano-optomechanical mirror formed by a suspended membrane pierced by a photonic crystal. By applying to the mirror a periodic electrostatic force induced by interdigitated electrodes integrated below the membrane, we evidence superharmonic resonances of our nano-electro-mechanical system; the constant phase shift of the oscillator across the resonance tongues is observed on the onset of principal harmonic and subharmonic excitation regimes.

  18. Nano-Electromechanical Systems: Displacement Detection and the Mechanical Single Electron Shuttle

    NASA Astrophysics Data System (ADS)

    Blick, R. H.; Beil, F. W.; Höhberger, E.; Erbe, A.; Weiss, C.

    For an introduction to nano-electromechanical systems we present measurements on nanomechanical resonators operating in the radio frequency range. We discuss in detail two different schemes of displacement detection for mechanical resonators, namely conventional reflection measurements of a probing signal and direct detection by capacitive coupling via a gate electrode. For capacitive detection we employ an on-chip preamplifier, which enables direct measurements of the resonator's disp lacement. We observe that the mechanical quality factor of the resonator depends on the detection technique applied, which is verified in model calculations and report on the detection of sub-harmonics. In the second part we extend our investigations to include transport of single electrons through an electron island on the tip of a nanomachined mechanical pendulum. The pendulum is operated by applying a modulating electromagnetic field in the range of 1 - 200 MHz, leading to mechanical oscillations between two laterally integrated source and drain contacts. Forming tunneling barriers the metallic tip shuttles single electrons from source to drain. The resulting tunneling current shows distinct features corresponding to the discrete mechanical eigenfrequencies of the pendulum. We report on measurements covering the temperature range from 300 K down to 4.2 K. The transport properties of the device are compared in detail to model calculations based on a Master-equation approach.

  19. Spring 2004 Industry Study Final Report: Strategic Materials

    DTIC Science & Technology

    2004-01-01

    decreasing processing costs. Processing costs can be reduced by using powder metallurgy technology to reduce waste and by seeking new markets to... market share is likely to remain fierce until the arrival of the next miniaturization technology , nanoelectromechanical system (NEMS). Smart...the transportation, medical, energy, information technology , and environmental industries will create the strongest economic pull for the

  20. Electricity Market Module - NEMS Documentation

    EIA Publications

    2017-01-01

    Documents the Electricity Market Module as it was used for the Annual Energy Outlook. The Electricity Market Module (EMM) is the electricity supply component of the National Energy Modeling System (NEMS). The EMM represents the generation, transmission, and pricing of electricity. It consists of four submodules: the Electricity Capacity Planning (ECP) Submodule, the Electricity Fuel Dispatch (EFD) Submodule, the Electricity Finance and Pricing (EFP) Submodule, and the Electricity Load and Demand (ELD) Submodule.

  1. The study of radiation effects in emerging micro and nano electro mechanical systems (M and NEMs)

    NASA Astrophysics Data System (ADS)

    Arutt, Charles N.; Alles, Michael L.; Liao, Wenjun; Gong, Huiqi; Davidson, Jim L.; Schrimpf, Ronald D.; Reed, Robert A.; Weller, Robert A.; Bolotin, Kirill; Nicholl, Ryan; Pham, Thang Toan; Zettl, Alex; Qingyang, Du; Hu, Juejun; Li, Mo; Alphenaar, Bruce W.; Lin, Ji-Tzuoh; Shurva, Pranoy Deb; McNamara, Shamus; Walsh, Kevin M.; X-L Feng, Philip; Hutin, Louis; Ernst, Thomas; Homeijer, Brian D.; Polcawich, Ronald G.; Proie, Robert M.; Jones, Jacob L.; Glaser, Evan R.; Cress, Cory D.; Bassiri-Gharb, Nazanin

    2017-01-01

    The potential of micro and nano electromechanical systems (M and NEMS) has expanded due to advances in materials and fabrication processes. A wide variety of materials are now being pursued and deployed for M and NEMS including silicon carbide (SiC), III-V materials, thin-film piezoelectric and ferroelectric, electro-optical and 2D atomic crystals such as graphene, hexagonal boron nitride (h-BN), and molybdenum disulfide (MoS2). The miniaturization, functionality and low-power operation offered by these types of devices are attractive for many application areas including physical sciences, medical, space and military uses, where exposure to radiation is a reliability consideration. Understanding the impact of radiation on these materials and devices is necessary for applications in radiation environments.

  2. Price Responsiveness in the AEO2003 NEMS Residential and Commercial Buildings Sector Models

    EIA Publications

    2003-01-01

    This paper describes the demand responses to changes in energy prices in the Annual Energy Outlook 2003 versions of the Residential and Commercial Demand Modules of the National Energy Modeling System (NEMS). It updates a similar paper completed for the Annual Energy Outlook 1999 version of the NEMS.

  3. Phase-locked loop based on nanoelectromechanical resonant-body field effect transistor

    NASA Astrophysics Data System (ADS)

    Bartsch, S. T.; Rusu, A.; Ionescu, A. M.

    2012-10-01

    We demonstrate the room-temperature operation of a silicon nanoelectromechanical resonant-body field effect transistor (RB-FET) embedded into phase-locked loop (PLL). The very-high frequency resonator uses on-chip electrostatic actuation and transistor-based displacement detection. The heterodyne frequency down-conversion based on resistive FET mixing provides a loop feedback signal with high signal-to-noise ratio. We identify key parameters for PLL operation, and analyze the performance of the RB-FET at the system level. Used as resonant mass detector, the experimental frequency stability in the ppm-range translates into sub atto-gram (10-18 g) sensitivity in high vacuum. The feedback and control system are generic and may be extended to other mechanical resonators with transistor properties, such as graphene membranes and carbon nanotubes.

  4. Exploring Carbon Nanotubes for Nanoscale Devices

    NASA Technical Reports Server (NTRS)

    Han, Jie; Dai; Anantram; Jaffe; Saini, Subhash (Technical Monitor)

    1998-01-01

    Carbon nanotubes (CNTs) are shown to promise great opportunities in nanoelectronic devices and nanoelectromechanical systems (NEMS) because of their inherent nanoscale sizes, intrinsic electric conductivities, and seamless hexagonal network architectures. I present our collaborative work with Stanford on exploring CNTs for nanodevices in this talk. The electrical property measurements suggest that metallic tubes are quantum wires. Furthermore, two and three terminal CNT junctions have been observed experimentally. We have proposed and studied CNT-based molecular switches and logic devices for future digital electronics. We also have studied CNTs based NEMS inclusing gears, cantilevers, and scanning probe microscopy tips. We investigate both chemistry and physics based aspects of the CNT NEMS. Our results suggest that CNT have ideal stiffness, vibrational frequencies, Q-factors, geometry-dependent electric conductivities, and the highest chemical and mechanical stabilities for the NEMS. The use of CNT SPM tips for nanolithography is presented for demonstration of the advantages of the CNT NEMS.

  5. Impact of different sampling strategies on score results of the Nine Equivalents of Nursing Manpower Use Score (NEMS).

    PubMed

    Junger, A; Hartmann, B; Klasen, J; Brenck, F; Röhrig, R; Hempelmann, G

    2007-01-01

    Prospective observational study to assess the impact of two different sampling strategies on the score results of the NEMS, used widely to estimate the amount of nursing workload in an ICU. NEMS scores of all patients admitted to the surgical ICU over a one-year period were automatically calculated twice a day with a patient data management system for each patient day on ICU using two different sampling strategies (NEMS(individual): 24-hour intervals starting from the time of admission; NEMS(8 a.m.): 24-hour intervals starting at 8 a.m.). NEMS(individual) and NEMS(8 a.m.) were collected on 3236 patient days; 687 patients were involved. Significantly lower scores were found for the NEMS(8 a.m.) (25.0 +/- 8.7) compared to the NEMS(individual) (26.1 +/- 8.9, p < 0.01); the interclass correlation coefficient (ICC) was good but not excellent: 0.78. The inter-rater correlation between the two NEMS scores was high or very high (kappa = 0.6-1.0) for six out of nine variables of the NEMS. Different sampling strategies produce different score values, especially due to the end of stay. This has to be taken into account when using the NEMS in quality assurance projects and multi-center studies.

  6. Viscoelastic coupling of nanoelectromechanical resonators.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Simonson, Robert Joseph; Staton, Alan W.

    2009-09-01

    This report summarizes work to date on a new collaboration between Sandia National Laboratories and the California Institute of Technology (Caltech) to utilize nanoelectromechanical resonators designed at Caltech as platforms to measure the mechanical properties of polymeric materials at length scales on the order of 10-50 nm. Caltech has succeeded in reproducibly building cantilever resonators having major dimensions on the order of 2-5 microns. These devices are fabricated in pairs, with free ends separated by reproducible gaps having dimensions on the order of 10-50 nm. By controlled placement of materials that bridge the very small gap between resonators, the mechanicalmore » devices become coupled through the test material, and the transmission of energy between the devices can be monitored. This should allow for measurements of viscoelastic properties of polymeric materials at high frequency over short distances. Our work to date has been directed toward establishing this measurement capability at Sandia.« less

  7. Lateral shearing optical gradient force in coupled nanobeam photonic crystal cavities

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Du, Han; Zhang, Xingwang; Chau, Fook Siong

    2016-04-25

    We report the experimental observation of lateral shearing optical gradient forces in nanoelectromechanical systems (NEMS) controlled dual-coupled photonic crystal (PhC) nanobeam cavities. With an on-chip integrated NEMS actuator, the coupled cavities can be mechanically reconfigured in the lateral direction while maintaining a constant coupling gap. Shearing optical gradient forces are generated when the two cavity centers are laterally displaced. In our experiments, positive and negative lateral shearing optical forces of 0.42 nN and 0.29 nN are observed with different pumping modes. This study may broaden the potential applications of the optical gradient force in nanophotonic devices and benefit the futuremore » nanooptoelectromechanical systems.« less

  8. NEMS Freight Transportation Module Improvement Study

    EIA Publications

    2015-01-01

    The U.S. Energy Information Administration (EIA) contracted with IHS Global, Inc. (IHS) to analyze the relationship between the value of industrial output, physical output, and freight movement in the United States for use in updating analytic assumptions and modeling structure within the National Energy Modeling System (NEMS) freight transportation module, including forecasting methodologies and processes to identify possible alternative approaches that would improve multi-modal freight flow and fuel consumption estimation.

  9. The role of Euler buckling instability in the fabrication of nanoelectromechanical systems on the basis of GaAs/AlGaAs heterostructures

    NASA Astrophysics Data System (ADS)

    Shevyrin, A. A.; Pogosov, A. G.; Budantsev, M. V.; Bakarov, A. K.; Toropov, A. I.; Ishutkin, S. V.; Shesterikov, E. V.; Kozhukhov, A. S.; Kosolobov, S. S.; Gavrilova, T. A.

    2012-12-01

    Mechanical stresses are investigated in suspended nanowires made on the basis of GaAs/AlGaAs heterostructures. Though there are no intentionally introduced stressor layers in the heterostructure, the nanowires are subject to Euler buckling instability. In the wide nanowires, the out-of-plane buckling is observed at length significantly smaller (3 times) than the theoretically estimated critical value, while in the narrow nanowires, the experimentally measured critical length of the in-plane buckling coincides with the theoretical estimation. The possible reasons for the obtained discrepancy are considered. The observed peculiarities should be taken into account in the fabrication of nanomechanical and nanoelectromechanical systems.

  10. Carbon-Based Nano-Electro-Mechanical-Systems

    NASA Technical Reports Server (NTRS)

    Kaul, A. B.; Khan, A. R.; Megerian, K. G.; Epp, L.; LeDuc, G.; Bagge, L.; Jennings, A. T.; Jang, D.; Greer, J. R.

    2011-01-01

    We provide an overview of our work where carbon-based nanostructures have been applied to two-dimensional (2D) planar and three-dimensional (3D) vertically-oriented nano-electro-mechanical (NEM) switches. In the first configuration, laterally oriented single-walled nanotubes (SWNTs) synthesized using thermal chemical vapor deposition (CVD) were implemented for forming bridge-type 2D NEMS switches, where switching voltages were on the order of a few volts. In the second configuration, vertically oriented carbon nanofibers (CNFs) synthesized using plasma-enhanced (PE) CVD have been explored for their potential application in 3D NEMS. We have performed nanomechanical measurements on such vertically oriented tubes using nanoindentation to determine the mechanical properties of the CNFs. Electrostatic switching was demonstrated in the CNFs synthesized on refractory metallic nitride substrates, where a nanoprobe was used as the actuating electrode inside a scanning-electron-microscope. The switching voltages were determined to be in the tens of volts range and van der Waals interactions at these length scales appeared significant, suggesting such structures are promising for nonvolatile memory applications. A finite element model was also developed to determine a theoretical pull-in voltage which was compared to experimental results.

  11. International Energy Module - NEMS Documentation

    EIA Publications

    2014-01-01

    Summarizes the overall structure of the International Energy Model and its interface with other NEMS modules, mathematical specifications of behavioral relationships, and data sources and estimation methods.

  12. 2D Crystal Semiconductors New Materials for GHz-THz Devices

    DTIC Science & Technology

    2015-10-02

    semiconductors are most promising for GHz-THz electronics. 3) Identify the major scattering mechanisms limiting mobility in 2D crystals towards high...Devices that do not operate on the traditional transistor mechanism exist today and operate below the SS limit. An example is a nanoelectromechanical...system (NEMS), which is the analog of a mechanical relay. Sub- stantial progress has been made in this area [14]. Due to mechanical moving parts, these

  13. Nanomechanical silicon resonators with intrinsic tunable gain and sub-nW power consumption.

    PubMed

    Bartsch, Sebastian T; Lovera, Andrea; Grogg, Daniel; Ionescu, Adrian M

    2012-01-24

    Nanoelectromechanical systems (NEMS) as integrated components for ultrasensitive sensing, time keeping, or radio frequency applications have driven the search for scalable nanomechanical transduction on-chip. Here, we present a hybrid silicon-on-insulator platform for building NEM oscillators in which fin field effect transistors (FinFETs) are integrated into nanomechanical silicon resonators. We demonstrate transistor amplification and signal mixing, coupled with mechanical motion at very high frequencies (25-80 MHz). By operating the transistor in the subthreshold region, the power consumption of resonators can be reduced to record-low nW levels, opening the way for the parallel operation of hundreds of thousands of NEM oscillators. The electromechanical charge modulation due to the field effect in a resonant transistor body constitutes a scalable nanomechanical motion detection all-on-chip and at room temperature. The new class of tunable NEMS represents a major step toward their integration in resonator arrays for applications in sensing and signal processing. © 2011 American Chemical Society

  14. EDITORIAL: World Year of Physics 2005 Focus on Photoemission and Electronic Structure

    NASA Astrophysics Data System (ADS)

    2005-04-01

    Around the year 1500, Leonardo da Vinci designed the first mechanical calculator connecting a number of toothed wheels for simple adding operations. Since then, mechanical systems have become a major part of the later industrial revolutions with an abundance of machines in our everyday lives. Only with the advent of semiconductor electronics, however, did microstructuring techniques become available to realize mechanical systems with dimensions below 100 microns. With most recent structure sizes now reaching the limit of a few nanometres, suspended nanostructures that couple mechanical with electronic motion have been constructed. Moreover, novel lithographic techniques have enabled the investigation of transport across hybrid structures such as. suspended carbon nanotubes or flexible molecular bridges connected to mesoscopic leads. In this invited focus issue of New Journal of Physics some of the leading experts in the field of nano-electromechanical systems (NEMS) describe the latest status and trends, from both an experimental and a theoretical perspective. A multitude of applications for NEMS are now within reach, ranging from high-frequency filters and switches in signal processing circuits, to ultra-sensitive sensors. In particular the development of mass sensors and scanning probe microscopy will be spurred by nano-mechanical systems. Considering that mechanical resonance frequencies of 1 GHz and more have already been achieved, these devices will be extremely sensitive and will offer high data acquisition rates. On a fundamental level NEMS enable the investigation of electron-phonon coupling in the absolute limit via, for example, single electrons interacting with single (quantized) phonons, the study of single electrons being shuttled via mechanical motion, and the manipulation of single molecules with nano-mechanical tweezers. The future for NEMS research looks certain to be exciting - we can expect it to help us build detectors of virtually any kind

  15. MC EMiNEM Maps the Interaction Landscape of the Mediator

    PubMed Central

    Niederberger, Theresa; Etzold, Stefanie; Lidschreiber, Michael; Maier, Kerstin C.; Martin, Dietmar E.; Fröhlich, Holger; Cramer, Patrick; Tresch, Achim

    2012-01-01

    The Mediator is a highly conserved, large multiprotein complex that is involved essentially in the regulation of eukaryotic mRNA transcription. It acts as a general transcription factor by integrating regulatory signals from gene-specific activators or repressors to the RNA Polymerase II. The internal network of interactions between Mediator subunits that conveys these signals is largely unknown. Here, we introduce MC EMiNEM, a novel method for the retrieval of functional dependencies between proteins that have pleiotropic effects on mRNA transcription. MC EMiNEM is based on Nested Effects Models (NEMs), a class of probabilistic graphical models that extends the idea of hierarchical clustering. It combines mode-hopping Monte Carlo (MC) sampling with an Expectation-Maximization (EM) algorithm for NEMs to increase sensitivity compared to existing methods. A meta-analysis of four Mediator perturbation studies in Saccharomyces cerevisiae, three of which are unpublished, provides new insight into the Mediator signaling network. In addition to the known modular organization of the Mediator subunits, MC EMiNEM reveals a hierarchical ordering of its internal information flow, which is putatively transmitted through structural changes within the complex. We identify the N-terminus of Med7 as a peripheral entity, entailing only local structural changes upon perturbation, while the C-terminus of Med7 and Med19 appear to play a central role. MC EMiNEM associates Mediator subunits to most directly affected genes, which, in conjunction with gene set enrichment analysis, allows us to construct an interaction map of Mediator subunits and transcription factors. PMID:22737066

  16. MC EMiNEM maps the interaction landscape of the Mediator.

    PubMed

    Niederberger, Theresa; Etzold, Stefanie; Lidschreiber, Michael; Maier, Kerstin C; Martin, Dietmar E; Fröhlich, Holger; Cramer, Patrick; Tresch, Achim

    2012-01-01

    The Mediator is a highly conserved, large multiprotein complex that is involved essentially in the regulation of eukaryotic mRNA transcription. It acts as a general transcription factor by integrating regulatory signals from gene-specific activators or repressors to the RNA Polymerase II. The internal network of interactions between Mediator subunits that conveys these signals is largely unknown. Here, we introduce MC EMiNEM, a novel method for the retrieval of functional dependencies between proteins that have pleiotropic effects on mRNA transcription. MC EMiNEM is based on Nested Effects Models (NEMs), a class of probabilistic graphical models that extends the idea of hierarchical clustering. It combines mode-hopping Monte Carlo (MC) sampling with an Expectation-Maximization (EM) algorithm for NEMs to increase sensitivity compared to existing methods. A meta-analysis of four Mediator perturbation studies in Saccharomyces cerevisiae, three of which are unpublished, provides new insight into the Mediator signaling network. In addition to the known modular organization of the Mediator subunits, MC EMiNEM reveals a hierarchical ordering of its internal information flow, which is putatively transmitted through structural changes within the complex. We identify the N-terminus of Med7 as a peripheral entity, entailing only local structural changes upon perturbation, while the C-terminus of Med7 and Med19 appear to play a central role. MC EMiNEM associates Mediator subunits to most directly affected genes, which, in conjunction with gene set enrichment analysis, allows us to construct an interaction map of Mediator subunits and transcription factors.

  17. Characterization of SiO{sub 2}/SiN{sub x} gate insulators for graphene based nanoelectromechanical systems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tóvári, E.; Csontos, M., E-mail: csontos@dept.phy.bme.hu; Kriváchy, T.

    2014-09-22

    The structural and magnetotransport characterization of graphene nanodevices exfoliated onto Si/SiO{sub 2}/SiN{sub x} heterostructures are presented. Improved visibility of the deposited flakes is achieved by optimal tuning of the dielectric film thicknesses. The conductance of single layer graphene Hall-bar nanostructures utilizing SiO{sub 2}/SiN{sub x} gate dielectrics were characterized in the quantum Hall regime. Our results highlight that, while exhibiting better mechanical and chemical stability, the effect of non-stoichiometric SiN{sub x} on the charge carrier mobility of graphene is comparable to that of SiO{sub 2}, demonstrating the merits of SiN{sub x} as an ideal material platform for graphene based nanoelectromechanical applications.

  18. OncoNEM: inferring tumor evolution from single-cell sequencing data.

    PubMed

    Ross, Edith M; Markowetz, Florian

    2016-04-15

    Single-cell sequencing promises a high-resolution view of genetic heterogeneity and clonal evolution in cancer. However, methods to infer tumor evolution from single-cell sequencing data lag behind methods developed for bulk-sequencing data. Here, we present OncoNEM, a probabilistic method for inferring intra-tumor evolutionary lineage trees from somatic single nucleotide variants of single cells. OncoNEM identifies homogeneous cellular subpopulations and infers their genotypes as well as a tree describing their evolutionary relationships. In simulation studies, we assess OncoNEM's robustness and benchmark its performance against competing methods. Finally, we show its applicability in case studies of muscle-invasive bladder cancer and essential thrombocythemia.

  19. Parametric nanomechanical amplification at very high frequency.

    PubMed

    Karabalin, R B; Feng, X L; Roukes, M L

    2009-09-01

    Parametric resonance and amplification are important in both fundamental physics and technological applications. Here we report very high frequency (VHF) parametric resonators and mechanical-domain amplifiers based on nanoelectromechanical systems (NEMS). Compound mechanical nanostructures patterned by multilayer, top-down nanofabrication are read out by a novel scheme that parametrically modulates longitudinal stress in doubly clamped beam NEMS resonators. Parametric pumping and signal amplification are demonstrated for VHF resonators up to approximately 130 MHz and provide useful enhancement of both resonance signal amplitude and quality factor. We find that Joule heating and reduced thermal conductance in these nanostructures ultimately impose an upper limit to device performance. We develop a theoretical model to account for both the parametric response and nonequilibrium thermal transport in these composite nanostructures. The results closely conform to our experimental observations, elucidate the frequency and threshold-voltage scaling in parametric VHF NEMS resonators and sensors, and establish the ultimate sensitivity limits of this approach.

  20. Scalable fabrication of carbon-based MEMS/NEMS and their applications: a review

    NASA Astrophysics Data System (ADS)

    Jiang, Shulan; Shi, Tielin; Zhan, Xiaobin; Xi, Shuang; Long, Hu; Gong, Bo; Li, Junjie; Cheng, Siyi; Huang, Yuanyuan; Tang, Zirong

    2015-11-01

    The carbon-based micro/nano electromechanical system (MEMS/NEMS) technique provides a powerful approach to large-scale manufacture of high-aspect-ratio carbon structures for wafer-level processing. The fabricated three-dimensional (3D) carbon structures have the advantages of excellent electrical and electrochemical properties, and superior biocompatibility. In order to improve their performance for applications in micro energy storage devices and microsensors, an increase in the footprint surface area is of great importance. Various approaches have been proposed for fabricating large surface area carbon-based structures, including the integration of nanostructures such as carbon nanotubes (CNTs), graphene, nanowires, nanofilms and nanowrinkles onto 3D structures, which has been proved to be effective and productive. Moreover, by etching the 3D photoresist microstructures through oxygen plasma or modifying the photoresist with specific materials which can be etched in the following pyrolysis process, micro/nano hierarchical carbon structures have been fabricated. These improved structures show excellent performance in various applications, especially in the fields of biological sensors, surface-enhanced Raman scattering, and energy storage devices such as micro-supercapacitors and fuel cells. With the rapid development of microelectronic devices, the carbon-based MEMS/NEMS technique could make more aggressive moves into microelectronics, sensors, miniaturized power systems, etc. In this review, the recent advances in the fabrication of micro/nano hierarchical carbon-based structures are introduced and the technical challenges and future outlook of the carbon-based MEMS/NEMS techniques are also analyzed.

  1. Large-area low-temperature ultrananocrystaline diamond (UNCD) films and integration with CMOS devices for monolithically integrated diamond MEMD/NEMS-CMOS systems.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sumant, A.V.; Auciello, O.; Yuan, H.-C

    2009-05-01

    Because of exceptional mechanical, chemical, and tribological properties, diamond has a great potential to be used as a material for the development of high-performance MEMS and NEMS such as resonators and switches compatible with harsh environments, which involve mechanical motion and intermittent contact. Integration of such MEMS/NEMS devices with complementary metal oxide semiconductor (CMOS) microelectronics will provide a unique platform for CMOS-driven commercial MEMS/NEMS. The main hurdle to achieve diamond-CMOS integration is the relatively high substrate temperatures (600-800 C) required for depositing conventional diamond thin films, which are well above the CMOS operating thermal budget (400 C). Additionally, a materialsmore » integration strategy has to be developed to enable diamond-CMOS integration. Ultrananocrystalline diamond (UNCD), a novel material developed in thin film form at Argonne, is currently the only microwave plasma chemical vapor deposition (MPCVD) grown diamond film that can be grown at 400 C, and still retain exceptional mechanical, chemical, and tribological properties comparable to that of single crystal diamond. We have developed a process based on MPCVD to synthesize UNCD films on up to 200 mm in diameter CMOS wafers, which will open new avenues for the fabrication of monolithically integrated CMOS-driven MEMS/NEMS based on UNCD. UNCD films were grown successfully on individual Si-based CMOS chips and on 200 mm CMOS wafers at 400 C in a MPCVD system, using Ar-rich/CH4 gas mixture. The CMOS devices on the wafers were characterized before and after UNCD deposition. All devices were performing to specifications with very small degradation after UNCD deposition and processing. A threshold voltage degradation in the range of 0.08-0.44V and transconductance degradation in the range of 1.5-9% were observed.« less

  2. The uncharacterized transcription factor YdhM is the regulator of the nemA gene, encoding N-ethylmaleimide reductase.

    PubMed

    Umezawa, Yoshimasa; Shimada, Tomohiro; Kori, Ayako; Yamada, Kayoko; Ishihama, Akira

    2008-09-01

    N-ethylmaleimide (NEM) has been used as a specific reagent of Cys modification in proteins and thus is toxic for cell growth. On the Escherichia coli genome, the nemA gene coding for NEM reductase is located downstream of the gene encoding an as-yet-uncharacterized transcription factor, YdhM. Disruption of the ydhM gene results in reduction of nemA expression even in the induced state, indicating that the two genes form a single operon. After in vitro genomic SELEX screening, one of the target recognition sequences for YdhM was identified within the promoter region for this ydhM-nemA operon. Both YdhM binding in vitro to the ydhM promoter region and transcription repression in vivo of the ydhM-nemA operon by YdhM were markedly reduced by the addition of NEM. Taken together, we propose that YdhM is the repressor for the nemA gene, thus hereafter designated NemR. The repressor function of NemR was inactivated by the addition of not only NEM but also other Cys modification reagents, implying that Cys modification of NemR renders it inactive. This is an addition to the mode of controlling activity of transcription factors by alkylation with chemical agents.

  3. Characterization of Plasma Synthesized Vertical Carbon Nanofibers for Nanoelectronics Applications

    NASA Technical Reports Server (NTRS)

    Lee, Jaesung; Feng, Philip X.-L.; Kaul, Anupama B.

    2013-01-01

    We report on the material characterization of carbon nanofibers (CNFs) which are assembled into a three-dimensional (3D) configuration for making new nanoelectromechanical systems (NEMS). High-resolution scanning electron microscopy (SEM) and x-ray electron dispersive spectroscopy (XEDS) are employed to decipher the morphology and chemical compositions of the CNFs at various locations along individual CNFs grown on silicon (Si) and refractory nitride (NbTiN) substrates, respectively. The measured characteristics suggest interesting properties of the CNF bodies and their capping catalyst nanoparticles, and growth mechanisms on the two substrates. Laser irradiation on the CNFs seems to cause thermal oxidation and melting of catalyst nanoparticles. The structural morphology and chemical compositions of the CNFs revealed in this study should aid in the applications of the CNFs to nanoelectronics and NEMS.

  4. Tribo-functionalizing Si and SU8 materials by surface modification for application in MEMS/NEMS actuator-based devices

    NASA Astrophysics Data System (ADS)

    Singh, R. A.; Satyanarayana, N.; Kustandi, T. S.; Sinha, S. K.

    2011-01-01

    Micro/nano-electro-mechanical-systems (MEMS/NEMS) are miniaturized devices built at micro/nanoscales. At these scales, the surface/interfacial forces are extremely strong and they adversely affect the smooth operation and the useful operating lifetimes of such devices. When these forces manifest in severe forms, they lead to material removal and thereby reduce the wear durability of the devices. In this paper, we present a simple, yet robust, two-step surface modification method to significantly enhance the tribological performance of MEMS/NEMS materials. The two-step method involves oxygen plasma treatment of polymeric films and the application of a nanolubricant, namely perfluoropolyether. We apply the two-step method to the two most important MEMS/NEMS structural materials, namely silicon and SU8 polymer. On applying surface modification to these materials, their initial coefficient of friction reduces by ~4-7 times and the steady-state coefficient of friction reduces by ~2.5-3.5 times. Simultaneously, the wear durability of both the materials increases by >1000 times. The two-step method is time effective as each of the steps takes the time duration of approximately 1 min. It is also cost effective as the oxygen plasma treatment is a part of the MEMS/NEMS fabrication process. The two-step method can be readily and easily integrated into MEMS/NEMS fabrication processes. It is anticipated that this method will work for any kind of structural material from which MEMS/NEMS are or can be made.

  5. A MEMS-based high frequency x-ray chopper.

    PubMed

    Siria, A; Dhez, O; Schwartz, W; Torricelli, G; Comin, F; Chevrier, J

    2009-04-29

    Time-resolved x-ray experiments require intensity modulation at high frequencies (advanced rotating choppers have nowadays reached the kHz range). We here demonstrate that a silicon microlever oscillating at 13 kHz with nanometric amplitude can be used as a high frequency x-ray chopper. We claim that using micro-and nanoelectromechanical systems (MEMS and NEMS), it will be possible to achieve higher frequencies in excess of hundreds of megahertz. Working at such a frequency can open a wealth of possibilities in chemistry, biology and physics time-resolved experiments.

  6. Controlled placement and orientation of nanostructures

    DOEpatents

    Zettl, Alex K; Yuzvinsky, Thomas D; Fennimore, Adam M

    2014-04-08

    A method for controlled deposition and orientation of molecular sized nanoelectromechanical systems (NEMS) on substrates is disclosed. The method comprised: forming a thin layer of polymer coating on a substrate; exposing a selected portion of the thin layer of polymer to alter a selected portion of the thin layer of polymer; forming a suspension of nanostructures in a solvent, wherein the solvent suspends the nanostructures and activates the nanostructures in the solvent for deposition; and flowing a suspension of nanostructures across the layer of polymer in a flow direction; thereby: depositing a nanostructure in the suspension of nanostructures only to the selected portion of the thin layer of polymer coating on the substrate to form a deposited nanostructure oriented in the flow direction. By selectively employing portions of the method above, complex NEMS may be built of simpler NEMSs components.

  7. NemR Is a Bleach-sensing Transcription Factor*

    PubMed Central

    Gray, Michael J.; Wholey, Wei-Yun; Parker, Benjamin W.; Kim, Minwook; Jakob, Ursula

    2013-01-01

    Hypochlorous acid (HOCl), the active component of household bleach, also functions as a powerful antimicrobial during the innate immune response. Despite its widespread use, surprisingly little is known about how cells sense or respond to HOCl. We now demonstrate that Escherichia coli NemR is a redox-regulated transcriptional repressor, which uses the oxidation status of HOCl-sensitive cysteine residues to respond to bleach and related reactive chlorine species. NemR controls bleach-mediated expression of two enzymes required for detoxification of reactive electrophiles: glyoxalase I and N-ethylmaleimide reductase. Both enzymes contribute to bacterial bleach survival. These results provide evidence that bleach resistance relies on the capacity of organisms to specifically sense reactive chlorine species and respond with the up-regulation of enzymes dedicated to detoxification of methylglyoxal and other reactive electrophiles. PMID:23536188

  8. A study on carbon nanotube bridge as a electromechanical memory device

    NASA Astrophysics Data System (ADS)

    Kang, Jeong Won; Ha Lee, Jun; Joo Lee, Hoong; Hwang, Ho Jung

    2005-04-01

    A nanoelectromechanical (NEM) nanotube random access memory (NRAM) device based on carbon nanotube (CNT) was investigated using atomistic simulations. For the CNT-based NEM memory, the mechanical properties of the CNT-bridge and van der Waals interactions between the CNT-bridge and substrate were very important. The critical amplitude of the CNT-bridge was 16% of the length of the CNT-bridge. As molecular dynamics time increased, the CNT-bridge went to the steady state under the electrostatic force with the damping of the potential and the kinetic energies of the CNT-bridge. The interatomic interaction between the CNT-bridge and substrate, value of the CNT-bridge slack, and damping rate of the CNT-bridge were very important for the operation of the NEM memory device as a nonvolatile memory.

  9. Fabrication of 3D Carbon Microelectromechanical Systems (C-MEMS).

    PubMed

    Pramanick, Bidhan; Martinez-Chapa, Sergio O; Madou, Marc; Hwang, Hyundoo

    2017-06-17

    A wide range of carbon sources are available in nature, with a variety of micro-/nanostructure configurations. Here, a novel technique to fabricate long and hollow glassy carbon microfibers derived from human hairs is introduced. The long and hollow carbon structures were made by the pyrolysis of human hair at 900 °C in a N2 atmosphere. The morphology and chemical composition of natural and pyrolyzed human hairs were investigated using scanning electron microscopy (SEM) and electron-dispersive X-ray spectroscopy (EDX), respectively, to estimate the physical and chemical changes due to pyrolysis. Raman spectroscopy was used to confirm the glassy nature of the carbon microstructures. Pyrolyzed hair carbon was introduced to modify screen-printed carbon electrodes ; the modified electrodes were then applied to the electrochemical sensing of dopamine and ascorbic acid. Sensing performance of the modified sensors was improved as compared to the unmodified sensors. To obtain the desired carbon structure design, carbon micro-/nanoelectromechanical system (C-MEMS/C-NEMS) technology was developed. The most common C-MEMS/C-NEMS fabrication process consists of two steps: (i) the patterning of a carbon-rich base material, such as a photosensitive polymer, using photolithography; and (ii) carbonization through the pyrolysis of the patterned polymer in an oxygen-free environment. The C-MEMS/NEMS process has been widely used to develop microelectronic devices for various applications, including in micro-batteries, supercapacitors, glucose sensors, gas sensors, fuel cells, and triboelectric nanogenerators. Here, recent developments of a high-aspect ratio solid and hollow carbon microstructures with SU8 photoresists are discussed. The structural shrinkage during pyrolysis was investigated using confocal microscopy and SEM. Raman spectroscopy was used to confirm the crystallinity of the structure, and the atomic percentage of the elements present in the material before and after

  10. Fabrication of polymeric nano-batteries array using anodic aluminum oxide templates.

    PubMed

    Zhao, Qiang; Cui, Xiaoli; Chen, Ling; Liu, Ling; Sun, Zhenkun; Jiang, Zhiyu

    2009-02-01

    Rechargeable nano-batteries were fabricated in the array pores of anodic aluminum oxide (AAO) template, combining template method and electrochemical method. The battery consisted of electropolymerized PPy electrode, porous TiO2 separator, and chemically polymerized PAn electrode was fabricated in the array pores of two-step anodizing aluminum oxide (AAO) membrane, based on three-step assembling method. It performs typical electrochemical battery behavior with good charge-discharge ability, and presents a capacity of 25 nAs. AFM results show the hexagonal array of nano-batteries' top side. The nano-battery may be a promising device for the development of Micro-Electro-Mechanical Systems (MEMS), and Nano-Electro-Mechanical Systems (NEMS).

  11. Escherichia coli NemA is an efficient chromate reductase that can be biologically immobilized to provide a cell free system for remediation of hexavalent chromium.

    PubMed

    Robins, Katherine J; Hooks, David O; Rehm, Bernd H A; Ackerley, David F

    2013-01-01

    Hexavalent chromium is a serious and widespread environmental pollutant. Although many bacteria have been identified that can transform highly water-soluble and toxic Cr(VI) to insoluble and relatively non-toxic Cr(III), bacterial bioremediation of Cr(VI) pollution is limited by a number of issues, in particular chromium toxicity to the remediating cells. To address this we sought to develop an immobilized enzymatic system for Cr(VI) remediation. To identify novel Cr(VI) reductase enzymes we first screened cell extracts from an Escherichia coli library of soluble oxidoreductases derived from a range of bacteria, but found that a number of these enzymes can reduce Cr(VI) indirectly, via redox intermediates present in the crude extracts. Instead, activity assays for 15 candidate enzymes purified as His6-tagged proteins identified E. coli NemA as a highly efficient Cr(VI) reductase (k(cat)/K(M)= 1.1×10(5) M(-1) s(-1) with NADH as cofactor). Fusion of nemA to the polyhydroxyalkanoate synthase gene phaC from Ralstonia eutropha enabled high-level biosynthesis of functionalized polyhydroxyalkanoate granules displaying stable and active NemA on their surface. When these granules were combined with either Bacillus subtilis glucose dehydrogenase or Candida boidinii formate dehydrogenase as a cofactor regenerating partner, high levels of chromate transformation were observed with only low initial concentrations of expensive NADH cofactor being required, the overall reaction being powered by consumption of the cheap sacrificial substrates glucose or formic acid, respectively. This system therefore offers promise as an economic solution for ex situ Cr(VI) remediation.

  12. Escherichia coli NemA Is an Efficient Chromate Reductase That Can Be Biologically Immobilized to Provide a Cell Free System for Remediation of Hexavalent Chromium

    PubMed Central

    Robins, Katherine J.; Hooks, David O.; Rehm, Bernd H. A.; Ackerley, David F.

    2013-01-01

    Hexavalent chromium is a serious and widespread environmental pollutant. Although many bacteria have been identified that can transform highly water-soluble and toxic Cr(VI) to insoluble and relatively non-toxic Cr(III), bacterial bioremediation of Cr(VI) pollution is limited by a number of issues, in particular chromium toxicity to the remediating cells. To address this we sought to develop an immobilized enzymatic system for Cr(VI) remediation. To identify novel Cr(VI) reductase enzymes we first screened cell extracts from an Escherichia coli library of soluble oxidoreductases derived from a range of bacteria, but found that a number of these enzymes can reduce Cr(VI) indirectly, via redox intermediates present in the crude extracts. Instead, activity assays for 15 candidate enzymes purified as His6-tagged proteins identified E. coli NemA as a highly efficient Cr(VI) reductase (kcat/KM  = 1.1×105 M−1s−1 with NADH as cofactor). Fusion of nemA to the polyhydroxyalkanoate synthase gene phaC from Ralstonia eutropha enabled high-level biosynthesis of functionalized polyhydroxyalkanoate granules displaying stable and active NemA on their surface. When these granules were combined with either Bacillus subtilis glucose dehydrogenase or Candida boidinii formate dehydrogenase as a cofactor regenerating partner, high levels of chromate transformation were observed with only low initial concentrations of expensive NADH cofactor being required, the overall reaction being powered by consumption of the cheap sacrificial substrates glucose or formic acid, respectively. This system therefore offers promise as an economic solution for ex situ Cr(VI) remediation. PMID:23527133

  13. Ultrasensitive optofluidic-nanoplasmonic BioNEMS for life sciences and point-of-care diagnostics

    NASA Astrophysics Data System (ADS)

    Yanik, Ahmet Ali

    2014-03-01

    Recent progress on the development of optofluidic-nanoplasmonic BioNEMS is reviewed in this proceeding. Following a brief summary of the fundamental limitations in current lab-on-chip platforms, optofluidic-nanoplasmonic BioNEMS are discussed in detail and means to overcome mass transport limitations are shown. Finally, nanofluidic approach is extended to a cross fluidic scheme for efficiently isolation of rare circulating tumor cells.

  14. Micro-electromechanical sensors in the analytical field.

    PubMed

    Zougagh, Mohammed; Ríos, Angel

    2009-07-01

    Micro- and nano-electromechanical systems (MEMS and NEMS) for use as sensors represent one of the most exciting new fields in analytical chemistry today. These systems are advantageous over currently available non-miniaturized sensors, such as quartz crystal microbalances, thickness shear mode resonators, and flexural plate wave oscillators, because of their high sensitivity, low cost and easy integration into automated systems. In this article, we present and discuss the evolution in the use of MEMS and NEMS, which are basically cantilever-type sensors, as good analytical tools for a wide variety of applications. We discuss the analytical features and the practical potential of micro(nano)-cantilever sensors, which combine the synergetic advantages of selectivity, provided by their functionalization, and the high sensitivity, which is attributed largely to the extremely small size of the sensing element. An insight is given into the different types of functionalization and detection strategies and a critical discussion is presented on the existing state of the art concerning the applications reported for mechanical microsensors. New developments and the possibilities for routine work in the near future are also covered.

  15. Highly Sensitive Electromechanical Piezoresistive Pressure Sensors Based on Large-Area Layered PtSe2 Films.

    PubMed

    Wagner, Stefan; Yim, Chanyoung; McEvoy, Niall; Kataria, Satender; Yokaribas, Volkan; Kuc, Agnieszka; Pindl, Stephan; Fritzen, Claus-Peter; Heine, Thomas; Duesberg, Georg S; Lemme, Max C

    2018-05-23

    Two-dimensional (2D) layered materials are ideal for micro- and nanoelectromechanical systems (MEMS/NEMS) due to their ultimate thinness. Platinum diselenide (PtSe 2 ), an exciting and unexplored 2D transition metal dichalcogenide material, is particularly interesting because its low temperature growth process is scalable and compatible with silicon technology. Here, we report the potential of thin PtSe 2 films as electromechanical piezoresistive sensors. All experiments have been conducted with semimetallic PtSe 2 films grown by thermally assisted conversion of platinum at a complementary metal-oxide-semiconductor (CMOS)-compatible temperature of 400 °C. We report high negative gauge factors of up to -85 obtained experimentally from PtSe 2 strain gauges in a bending cantilever beam setup. Integrated NEMS piezoresistive pressure sensors with freestanding PMMA/PtSe 2 membranes confirm the negative gauge factor and exhibit very high sensitivity, outperforming previously reported values by orders of magnitude. We employ density functional theory calculations to understand the origin of the measured negative gauge factor. Our results suggest PtSe 2 as a very promising candidate for future NEMS applications, including integration into CMOS production lines.

  16. Development of an efficient multigrid method for the NEM form of the multigroup neutron diffusion equation

    NASA Astrophysics Data System (ADS)

    Al-Chalabi, Rifat M. Khalil

    1997-09-01

    Development of an improvement to the computational efficiency of the existing nested iterative solution strategy of the Nodal Exapansion Method (NEM) nodal based neutron diffusion code NESTLE is presented. The improvement in the solution strategy is the result of developing a multilevel acceleration scheme that does not suffer from the numerical stalling associated with a number of iterative solution methods. The acceleration scheme is based on the multigrid method, which is specifically adapted for incorporation into the NEM nonlinear iterative strategy. This scheme optimizes the computational interplay between the spatial discretization and the NEM nonlinear iterative solution process through the use of the multigrid method. The combination of the NEM nodal method, calculation of the homogenized, neutron nodal balance coefficients (i.e. restriction operator), efficient underlying smoothing algorithm (power method of NESTLE), and the finer mesh reconstruction algorithm (i.e. prolongation operator), all operating on a sequence of coarser spatial nodes, constitutes the multilevel acceleration scheme employed in this research. Two implementations of the multigrid method into the NESTLE code were examined; the Imbedded NEM Strategy and the Imbedded CMFD Strategy. The main difference in implementation between the two methods is that in the Imbedded NEM Strategy, the NEM solution is required at every MG level. Numerical tests have shown that the Imbedded NEM Strategy suffers from divergence at coarse- grid levels, hence all the results for the different benchmarks presented here were obtained using the Imbedded CMFD Strategy. The novelties in the developed MG method are as follows: the formulation of the restriction and prolongation operators, and the selection of the relaxation method. The restriction operator utilizes a variation of the reactor physics, consistent homogenization technique. The prolongation operator is based upon a variant of the pin power

  17. Sensing of single electrons using micro and nano technologies: a review

    NASA Astrophysics Data System (ADS)

    Jalil, Jubayer; Zhu, Yong; Ekanayake, Chandima; Ruan, Yong

    2017-04-01

    During the last three decades, the remarkable dynamic features of microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS), and advances in solid-state electronics hold much potential for the fabrication of extremely sensitive charge sensors. These sensors have a broad range of applications, such as those involving the measurement of ionization radiation, detection of bio-analyte and aerosol particles, mass spectrometry, scanning tunneling microscopy, and quantum computation. Designing charge sensors (also known as charge electrometers) for electrometry is deemed significant because of the sensitivity and resolution issues in the range of micro- and nano-scales. This article reviews the development of state-of-the-art micro- and nano-charge sensors, and discusses their technological challenges for practical implementation.

  18. Carbon nanotube chemistry and assembly for electronic devices

    NASA Astrophysics Data System (ADS)

    Derycke, Vincent; Auvray, Stéphane; Borghetti, Julien; Chung, Chia-Ling; Lefèvre, Roland; Lopez-Bezanilla, Alejandro; Nguyen, Khoa; Robert, Gaël; Schmidt, Gregory; Anghel, Costin; Chimot, Nicolas; Lyonnais, Sébastien; Streiff, Stéphane; Campidelli, Stéphane; Chenevier, Pascale; Filoramo, Arianna; Goffman, Marcelo F.; Goux-Capes, Laurence; Latil, Sylvain; Blase, Xavier; Triozon, François; Roche, Stephan; Bourgoin, Jean-Philippe

    2009-05-01

    Carbon nanotubes (CNTs) have exceptional physical properties that make them one of the most promising building blocks for future nanotechnologies. They may in particular play an important role in the development of innovative electronic devices in the fields of flexible electronics, ultra-high sensitivity sensors, high frequency electronics, opto-electronics, energy sources and nano-electromechanical systems (NEMS). Proofs of concept of several high performance devices already exist, usually at the single device level, but there remain many serious scientific issues to be solved before the viability of such routes can be evaluated. In particular, the main concern regards the controlled synthesis and positioning of nanotubes. In our opinion, truly innovative use of these nano-objects will come from: (i) the combination of some of their complementary physical properties, such as combining their electrical and mechanical properties; (ii) the combination of their properties with additional benefits coming from other molecules grafted on the nanotubes (this route being particularly relevant for gas- and bio-sensors, opto-electronic devices and energy sources); and (iii) the use of chemically- or bio-directed self-assembly processes to allow the efficient combination of several devices into functional arrays or circuits. In this article, we review our recent results concerning nanotube chemistry and assembly and their use to develop electronic devices. In particular, we present carbon nanotube field effect transistors and their chemical optimization, high frequency nanotube transistors, nanotube-based opto-electronic devices with memory capabilities and nanotube-based nano-electromechanical systems (NEMS). The impact of chemical functionalization on the electronic properties of CNTs is analyzed on the basis of theoretical calculations. To cite this article: V. Derycke et al., C. R. Physique 10 (2009).

  19. A bi-stable nanoelectromechanical non-volatile memory based on van der Waals force

    NASA Astrophysics Data System (ADS)

    Soon, Bo Woon; Jiaqiang Ng, Eldwin; Qian, You; Singh, Navab; Julius Tsai, Minglin; Lee, Chengkuo

    2013-07-01

    By using complementary-metal-oxide-semiconductor processes, a silicon based bi-stable nanoelectromechanical non-volatile memory is fabricated and characterized. The main feature of this device is an 80 nm wide and 3 μm high silicon nanofin (SiNF) of a high aspect ratio (1:35). The switching mechanism is realized by electrostatic actuation between two lateral electrodes, i.e., terminals. Bi-stable hysteresis behavior is demonstrated when the SiNF maintains its contact to one of the two terminals by leveraging on van der Waals force even after voltage bias is turned off. The compelling results indicate that this design is promising for realization of high density non-volatile memory application due to its nano-scale footprint and zero on-hold power consumption.

  20. Nanotechnology: Opportunities and Challenges

    NASA Technical Reports Server (NTRS)

    Meyyappan, Meyya

    2003-01-01

    Nanotechnology seeks to exploit novel physical, chemical, biological, mechanical, electrical, and other properties, which arise primarily due to the nanoscale nature of certain materials. A key example is carbon nanotubes (CNTs) which exhibit unique electrical and extraordinary mechanical properties and offer remarkable potential for revolutionary applications in electronics devices, computing, and data storage technology, sensors, composites, nanoelectromechanical systems (NEMS), and as tip in scanning probe microscopy (SPM) for imaging and nanolithography. Thus the CNT synthesis, characterization, and applications touch upon all disciplines of science and engineering. This presentation will provide an overview and progress report on this and other major research candidates in Nanotechnology and address opportunities and challenges ahead.

  1. Nano-electro-mechanical pump: Giant pumping of water in carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Farimani, Amir Barati; Heiranian, Mohammad; Aluru, Narayana R.

    2016-05-01

    A fully controllable nano-electro-mechanical device that can pump fluids at nanoscale is proposed. Using molecular dynamics simulations, we show that an applied electric field to an ion@C60 inside a water-filled carbon nanotube can pump water with excellent efficiency. The key physical mechanism governing the fluid pumping is the conversion of electrical energy into hydrodynamic flow with efficiencies as high as 64%. Our results show that water can be compressed up to 7% higher than its bulk value by applying electric fields. High flux of water (up to 13,000 molecules/ns) is obtained by the electro-mechanical, piston-cylinder-like moving mechanism of the ion@C60 in the CNT. This large flux results from the piston-like mechanism, compressibility of water (increase in density of water due to molecular ordering), orienting dipole along the electric field and efficient electrical to mechanical energy conversion. Our findings can pave the way towards efficient energy conversion, pumping of fluids at nanoscale, and drug delivery.

  2. Nano-electro-mechanical pump: Giant pumping of water in carbon nanotubes.

    PubMed

    Farimani, Amir Barati; Heiranian, Mohammad; Aluru, Narayana R

    2016-05-19

    A fully controllable nano-electro-mechanical device that can pump fluids at nanoscale is proposed. Using molecular dynamics simulations, we show that an applied electric field to an ion@C60 inside a water-filled carbon nanotube can pump water with excellent efficiency. The key physical mechanism governing the fluid pumping is the conversion of electrical energy into hydrodynamic flow with efficiencies as high as 64%. Our results show that water can be compressed up to 7% higher than its bulk value by applying electric fields. High flux of water (up to 13,000 molecules/ns) is obtained by the electro-mechanical, piston-cylinder-like moving mechanism of the ion@C60 in the CNT. This large flux results from the piston-like mechanism, compressibility of water (increase in density of water due to molecular ordering), orienting dipole along the electric field and efficient electrical to mechanical energy conversion. Our findings can pave the way towards efficient energy conversion, pumping of fluids at nanoscale, and drug delivery.

  3. Static deflection analysis of non prismatic multilayer p-NEMS cantilevers under electrical load

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pavithra, M., E-mail: pavithramasi78@gmail.com; Muruganand, S.

    2016-04-13

    Deflection of Euler-Bernoulli non prismatic multilayer piezoelectric nano electromechanical (p-NEMS) cantilever beams have been studied theoretically for various profiles of p-NEMS cantilevers by applying the electrical load. This problem has been answered by applying the boundary conditions derived by simple polynomials. This method is applied for various profiles like rectangular and trapezoidal by varying the thickness of the piezoelectric layer as well as the material. The obtained results provide the better deflection for trapezoidal profile with ZnO piezo electric layer of suitable nano cantilevers for nano scale applications.

  4. Nano-electro-mechanical pump: Giant pumping of water in carbon nanotubes

    PubMed Central

    Farimani, Amir Barati; Heiranian, Mohammad; Aluru, Narayana R.

    2016-01-01

    A fully controllable nano-electro-mechanical device that can pump fluids at nanoscale is proposed. Using molecular dynamics simulations, we show that an applied electric field to an ion@C60 inside a water-filled carbon nanotube can pump water with excellent efficiency. The key physical mechanism governing the fluid pumping is the conversion of electrical energy into hydrodynamic flow with efficiencies as high as 64%. Our results show that water can be compressed up to 7% higher than its bulk value by applying electric fields. High flux of water (up to 13,000 molecules/ns) is obtained by the electro-mechanical, piston-cylinder-like moving mechanism of the ion@C60 in the CNT. This large flux results from the piston-like mechanism, compressibility of water (increase in density of water due to molecular ordering), orienting dipole along the electric field and efficient electrical to mechanical energy conversion. Our findings can pave the way towards efficient energy conversion, pumping of fluids at nanoscale, and drug delivery. PMID:27193507

  5. Controlling Casimir force via coherent driving field

    NASA Astrophysics Data System (ADS)

    Ahmad, Rashid; Abbas, Muqaddar; Ahmad, Iftikhar; Qamar, Sajid

    2016-04-01

    A four level atom-field configuration is used to investigate the coherent control of Casimir force between two identical plates made up of chiral atomic media and separated by vacuum of width d. The electromagnetic chirality-induced negative refraction is obtained via atomic coherence. The behavior of Casimir force is investigated using Casimir-Lifshitz formula. It is noticed that Casimir force can be switched from repulsive to attractive and vice versa via coherent control of the driving field. This switching feature provides new possibilities of using the repulsive Casimir force in the development of new emerging technologies, such as, micro-electro-mechanical and nano-electro-mechanical systems, i.e., MEMS and NEMS, respectively.

  6. SOI-silicon as structural layer for NEMS applications

    NASA Astrophysics Data System (ADS)

    Villarroya, Maria; Figueras, Eduard; Perez-Murano, Francesc; Campabadal, Francesca; Esteve, Jaume; Barniol, Nuria

    2003-04-01

    The objective of this paper is to present the compatibilization between a standard CMOS on bulk silicon process and the fabrication of nanoelectromechanical systems using Silicon On Insulator (SOI) wafers as substrate. This compatibilization is required as first step to fabricate a very high sensitive mass sensor based on a resonant cantilever with nanometer dimensions using the crystal silicon COI layer as the structural layer. The cantilever is driven electrostatically to its resonance frequency by an electrode placed parallel to the cantilever. A capacitive readout is performed. To achieve very high resolution, very small dimensions of the cantilever (nanometer range) are needed. For this reason, the control and excitation circuitry has to be integrated on the same substrate than the cantilever. Prior to the development of this sensor, it is necessary to develop a substrate able to be used first to integrate a standard CMOS circuit and afterwards to fabricate the nano-resonator. Starting from a SOI wafer and using very simple processes, the SOI silicon layer is removed, except from the areas in which nano-structures will be fabricated; obtaining a silicon substrate with islands with a SOI structure. The CMOS circuitry will be integrated on the bulk silicon region, while the remainder SOI region will be used for the nanoresonator. The silicon oxide of this SOI region is used as insulator; and as sacrificial layer, etched to release the cantilever from the substrate. To assure the cover of the different CMOS layers over the step of the islands, it is essential to avoid very sharp steps.

  7. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Samanta, C.; Yasasvi Gangavarapu, P. R.; Naik, A. K.

    Atomically thin two dimensional (2D) layered materials have emerged as a new class of material for nanoelectromechanical systems (NEMS) due to their extraordinary mechanical properties and ultralow mass density. Among them, graphene has been the material of choice for nanomechanical resonator. However, recent interest in 2D chalcogenide compounds has also spurred research in using materials such as MoS{sub 2} for the NEMS applications. As the dimensions of devices fabricated using these materials shrink down to atomically thin membrane, strain and nonlinear effects have become important. A clear understanding of the nonlinear effects and the ability to manipulate them is essentialmore » for next generation sensors. Here, we report on all electrical actuation and detection of few-layer MoS{sub 2} resonator. The ability to electrically detect multiple modes and actuate the modes deep into the nonlinear regime enables us to probe the nonlinear coupling between various vibrational modes. The modal coupling in our device is strong enough to detect three distinct internal resonances.« less

  8. Nanoeletromechanical switch and logic circuits formed therefrom

    DOEpatents

    Nordquist, Christopher D [Albuquerque, NM; Czaplewski, David A [Albuquerque, NM

    2010-05-18

    A nanoelectromechanical (NEM) switch is formed on a substrate with a source electrode containing a suspended electrically-conductive beam which is anchored to the substrate at each end. This beam, which can be formed of ruthenium, bows laterally in response to a voltage applied between a pair of gate electrodes and the source electrode to form an electrical connection between the source electrode and a drain electrode located near a midpoint of the beam. Another pair of gate electrodes and another drain electrode can be located on an opposite side of the beam to allow for switching in an opposite direction. The NEM switch can be used to form digital logic circuits including NAND gates, NOR gates, programmable logic gates, and SRAM and DRAM memory cells which can be used in place of conventional CMOS circuits, or in combination therewith.

  9. Novel Material Integration for Reliable and Energy-Efficient NEM Relay Technology

    NASA Astrophysics Data System (ADS)

    Chen, I.-Ru

    Energy-efficient switching devices have become ever more important with the emergence of ubiquitous computing. NEM relays are promising to complement CMOS transistors as circuit building blocks for future ultra-low-power information processing, and as such have recently attracted significant attention from the semiconductor industry and researchers. Relay technology potentially can overcome the energy efficiency limit for conventional CMOS technology due to several key characteristics, including zero OFF-state leakage, abrupt switching behavior, and potentially very low active energy consumption. However, two key issues must be addressed for relay technology to reach its full potential: surface oxide formation at the contacting surfaces leading to increased ON-state resistance after switching, and high switching voltages due to strain gradient present within the relay structure. This dissertation advances NEM relay technology by investigating solutions to both of these pressing issues. Ruthenium, whose native oxide is conductive, is proposed as the contacting material to improve relay ON-state resistance stability. Ruthenium-contact relays are fabricated after overcoming several process integration challenges, and show superior ON-state resistance stability in electrical measurements and extended device lifetime. The relay structural film is optimized via stress matching among all layers within the structure, to provide lower strain gradient (below 10E-3/microm -1) and hence lower switching voltage. These advancements in relay technology, along with the integration of a metallic interconnect layer, enable complex relay-based circuit demonstration. In addition to the experimental efforts, this dissertation theoretically analyzes the energy efficiency limit of a NEM switch, which is generally believed to be limited by the surface adhesion energy. New compact (<1 microm2 footprint), low-voltage (<0.1 V) switch designs are proposed to overcome this limit. The results

  10. DRUG-NEM: Optimizing drug combinations using single-cell perturbation response to account for intratumoral heterogeneity

    PubMed Central

    Anchang, Benedict; Davis, Kara L.; Fienberg, Harris G.; Bendall, Sean C.; Karacosta, Loukia G.; Tibshirani, Robert; Nolan, Garry P.; Plevritis, Sylvia K.

    2018-01-01

    An individual malignant tumor is composed of a heterogeneous collection of single cells with distinct molecular and phenotypic features, a phenomenon termed intratumoral heterogeneity. Intratumoral heterogeneity poses challenges for cancer treatment, motivating the need for combination therapies. Single-cell technologies are now available to guide effective drug combinations by accounting for intratumoral heterogeneity through the analysis of the signaling perturbations of an individual tumor sample screened by a drug panel. In particular, Mass Cytometry Time-of-Flight (CyTOF) is a high-throughput single-cell technology that enables the simultaneous measurements of multiple (>40) intracellular and surface markers at the level of single cells for hundreds of thousands of cells in a sample. We developed a computational framework, entitled Drug Nested Effects Models (DRUG-NEM), to analyze CyTOF single-drug perturbation data for the purpose of individualizing drug combinations. DRUG-NEM optimizes drug combinations by choosing the minimum number of drugs that produce the maximal desired intracellular effects based on nested effects modeling. We demonstrate the performance of DRUG-NEM using single-cell drug perturbation data from tumor cell lines and primary leukemia samples. PMID:29654148

  11. Nanogold as NEMS platform: past, present, and future

    NASA Astrophysics Data System (ADS)

    Cornejo-Monroy, Delfino; Acosta-Torres, Laura S.; Castaño, Victor M.

    2012-06-01

    Gold has been a biomedical material since ancient times. We shall review the historical uses of gold, in different forms as well as the properties of this metal, which make it very attractive for MEMS and NEMS applications. In particular, we will discuss the synthesis and physic-chemical characteristics of nano particles of gold, emphasizing the role of surface modification, which enables the nano gold to act as a true nano reactor or a nano platform to develop various functions at the nanoscale. Finally, we will describe the use of nano gold for drug targeting and disease detection.

  12. Generalized Knudsen Number for Oscillatory Flows Generated by MEMS and NEMS Resonators

    NASA Astrophysics Data System (ADS)

    Ekinci, Kamil; Kara, Vural; Yakhot, Victor

    2017-11-01

    We have explored the scaling behavior of oscillatory flows that are generated by the oscillations of MEMS and NEMS resonators in a gas. If the gas is gradually rarefied, the Navier-Stokes equations begin to fail and a kinetic description of the flow becomes more appropriate. The failure of the Navier-Stokes equations can be thought to take place via two different physical mechanisms: either the continuum hypothesis breaks down as a result of a finite size effect; or local equilibrium is violated due to the high rate of strain. By independently tuning the relevant linear dimensions and the frequencies of the MEMS and NEMS resonators, we experimentally observe these two different physical mechanisms. All the experimental data, however, can be collapsed using a single dimensionless scaling parameter that combines the linear dimension and the frequency of each resonator. This proposed Knudsen number for oscillatory flows is rooted in a fundamental symmetry principle, namely Galilean invariance. We acknowledge support from US NSF through Grant No. CBET-1604075.

  13. Nonlinear Dynamics of Nanomechanical Resonators

    NASA Astrophysics Data System (ADS)

    Ramakrishnan, Subramanian; Gulak, Yuiry; Sundaram, Bala; Benaroya, Haym

    2007-03-01

    Nanoelectromechanical systems (NEMS) offer great promise for many applications including motion and mass sensing. Recent experimental results suggest the importance of nonlinear effects in NEMS, an issue which has not been addressed fully in theory. We report on a nonlinear extension of a recent analytical model by Armour et al [1] for the dynamics of a single-electron transistor (SET) coupled to a nanomechanical resonator. We consider the nonlinear resonator motion in both (a) the Duffing and (b) nonlinear pendulum regimes. The corresponding master equations are derived and solved numerically and we consider moment approximations as well. In the Duffing case with hardening stiffness, we observe that the resonator is damped by the SET at a significantly higher rate. In the cases of softening stiffness and the pendulum, there exist regimes where the SET adds energy to the resonator. To our knowledge, this is the first instance of a single model displaying both negative and positive resonator damping in different dynamical regimes. The implications of the results for SET sensitivity as well as for, as yet unexplained, experimental results will be discussed. 1. Armour et al. Phys.Rev.B (69) 125313 (2004).

  14. Overview of MEMS/NEMS technology development for space applications at NASA/JPL

    NASA Astrophysics Data System (ADS)

    George, Thomas

    2003-04-01

    This paper highlights the current technology development activities of the MEMS Technology Group at JPL. A diverse range of MEMS/NEMS technologies are under development, that are primarily applicable to NASA"s needs in the area of robotic planetary exploration. MEMS/NEMS technologies have obvious advantages for space applications, since they offer the promise of highly capable devices with ultra low mass, size and power consumption. However, the key challenge appears to be in finding efficient means to transition these technologies into "customer" applications. A brief description of this problem is presented along with the Group"s innovative approach to rapidly advance the maturity of technologies via insertion into space missions. Also described are some of the major capabilities of the MEMS Technology Group. A few important examples from among the broad classes of technologies being developed are discussed, these include the "Spider Web Bolometer", High-Performance Miniature Gyroscopes, an Electron Luminescence X-ray Spectrometer, a MEMS-based "Knudsen" Thermal Transpiration pump, MEMS Inchworm Actuators, and Nanowire-based Biological/Chemical Sensors.

  15. Top-Down CMOS-NEMS Polysilicon Nanowire with Piezoresistive Transduction

    PubMed Central

    Marigó, Eloi; Sansa, Marc; Pérez-Murano, Francesc; Uranga, Arantxa; Barniol, Núria

    2015-01-01

    A top-down clamped-clamped beam integrated in a CMOS technology with a cross section of 500 nm × 280 nm has been electrostatic actuated and sensed using two different transduction methods: capacitive and piezoresistive. The resonator made from a single polysilicon layer has a fundamental in-plane resonance at 27 MHz. Piezoresistive transduction avoids the effect of the parasitic capacitance assessing the capability to use it and enhance the CMOS-NEMS resonators towards more efficient oscillator. The displacement derived from the capacitive transduction allows to compute the gauge factor for the polysilicon material available in the CMOS technology. PMID:26184222

  16. Top-Down CMOS-NEMS Polysilicon Nanowire with Piezoresistive Transduction.

    PubMed

    Marigó, Eloi; Sansa, Marc; Pérez-Murano, Francesc; Uranga, Arantxa; Barniol, Núria

    2015-07-14

    A top-down clamped-clamped beam integrated in a CMOS technology with a cross section of 500 nm × 280 nm has been electrostatic actuated and sensed using two different transduction methods: capacitive and piezoresistive. The resonator made from a single polysilicon layer has a fundamental in-plane resonance at 27 MHz. Piezoresistive transduction avoids the effect of the parasitic capacitance assessing the capability to use it and enhance the CMOS-NEMS resonators towards more efficient oscillator. The displacement derived from the capacitive transduction allows to compute the gauge factor for the polysilicon material available in the CMOS technology.

  17. Plasmidic Expression of nemA and yafC* Increased Resistance of Ethanologenic Escherichia coli LY180 to Nonvolatile Side Products from Dilute Acid Treatment of Sugarcane Bagasse and Artificial Hydrolysate

    PubMed Central

    Shi, Aiqin; Zheng, Huabao; Yomano, Lorraine P.; York, Sean W.; Shanmugam, Keelnatham T.

    2016-01-01

    Hydrolysate-resistant Escherichia coli SL100 was previously isolated from ethanologenic LY180 after sequential transfers in AM1 medium containing a dilute acid hydrolysate of sugarcane bagasse and was used as a source of resistance genes. Many genes that affect tolerance to furfural, the most abundant inhibitor, have been described previously. To identify genes associated with inhibitors other than furfural, plasmid clones were selected in an artificial hydrolysate that had been treated with a vacuum to remove furfural. Two new resistance genes were discovered from Sau3A1 libraries of SL100 genomic DNA: nemA (N-ethylmaleimide reductase) and a putative regulatory gene containing a mutation in the coding region, yafC*. The presence of these mutations in SL100 was confirmed by sequencing. A single mutation was found in the upstream regulatory region of nemR (nemRA operon) in SL100. This mutation increased nemA activity 20-fold over that of the parent organism (LY180) in AM1 medium without hydrolysate and increased nemA mRNA levels >200-fold. Addition of hydrolysates induced nemA expression (mRNA and activity), in agreement with transcriptional control. NemA activity was stable in cell extracts (9 h, 37°C), eliminating a role for proteinase in regulation. LY180 with a plasmid expressing nemA or yafC* was more resistant to a vacuum-treated sugarcane bagasse hydrolysate and to a vacuum-treated artificial hydrolysate than LY180 with an empty-vector control. Neither gene affected furfural tolerance. The vacuum-treated hydrolysates inhibited the reduction of N-ethylmaleimide by NemA while also serving as substrates. Expression of the nemA or yafC* plasmid in LY180 doubled the rate of ethanol production from the vacuum-treated sugarcane bagasse hydrolysate. PMID:26826228

  18. Plasmidic Expression of nemA and yafC* Increased Resistance of Ethanologenic Escherichia coli LY180 to Nonvolatile Side Products from Dilute Acid Treatment of Sugarcane Bagasse and Artificial Hydrolysate.

    PubMed

    Shi, Aiqin; Zheng, Huabao; Yomano, Lorraine P; York, Sean W; Shanmugam, Keelnatham T; Ingram, Lonnie O

    2016-01-29

    Hydrolysate-resistant Escherichia coli SL100 was previously isolated from ethanologenic LY180 after sequential transfers in AM1 medium containing a dilute acid hydrolysate of sugarcane bagasse and was used as a source of resistance genes. Many genes that affect tolerance to furfural, the most abundant inhibitor, have been described previously. To identify genes associated with inhibitors other than furfural, plasmid clones were selected in an artificial hydrolysate that had been treated with a vacuum to remove furfural. Two new resistance genes were discovered from Sau3A1 libraries of SL100 genomic DNA: nemA (N-ethylmaleimide reductase) and a putative regulatory gene containing a mutation in the coding region, yafC*. The presence of these mutations in SL100 was confirmed by sequencing. A single mutation was found in the upstream regulatory region of nemR (nemRA operon) in SL100. This mutation increased nemA activity 20-fold over that of the parent organism (LY180) in AM1 medium without hydrolysate and increased nemA mRNA levels >200-fold. Addition of hydrolysates induced nemA expression (mRNA and activity), in agreement with transcriptional control. NemA activity was stable in cell extracts (9 h, 37°C), eliminating a role for proteinase in regulation. LY180 with a plasmid expressing nemA or yafC* was more resistant to a vacuum-treated sugarcane bagasse hydrolysate and to a vacuum-treated artificial hydrolysate than LY180 with an empty-vector control. Neither gene affected furfural tolerance. The vacuum-treated hydrolysates inhibited the reduction of N-ethylmaleimide by NemA while also serving as substrates. Expression of the nemA or yafC* plasmid in LY180 doubled the rate of ethanol production from the vacuum-treated sugarcane bagasse hydrolysate. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  19. Parametric amplification in MoS2 drum resonator.

    PubMed

    Prasad, Parmeshwar; Arora, Nishta; Naik, A K

    2017-11-30

    Parametric amplification is widely used in diverse areas from optics to electronic circuits to enhance low level signals by varying relevant system parameters. Parametric amplification has also been performed in several micro-nano resonators including nano-electromechanical system (NEMS) resonators based on a two-dimensional (2D) material. Here, we report the enhancement of mechanical response in a MoS 2 drum resonator using degenerate parametric amplification. We use parametric pumping to modulate the spring constant of the MoS 2 resonator and achieve a 10 dB amplitude gain. We also demonstrate quality factor enhancement in the resonator with parametric amplification. We investigate the effect of cubic nonlinearity on parametric amplification and show that it limits the gain of the mechanical resonator. Amplifying ultra-small displacements at room temperature and understanding the limitations of the amplification in these devices is key for using these devices for practical applications.

  20. Graphitized silicon carbide microbeams: wafer-level, self-aligned graphene on silicon wafers

    NASA Astrophysics Data System (ADS)

    Cunning, Benjamin V.; Ahmed, Mohsin; Mishra, Neeraj; Ranjbar Kermany, Atieh; Wood, Barry; Iacopi, Francesca

    2014-08-01

    Currently proven methods that are used to obtain devices with high-quality graphene on silicon wafers involve the transfer of graphene flakes from a growth substrate, resulting in fundamental limitations for large-scale device fabrication. Moreover, the complex three-dimensional structures of interest for microelectromechanical and nanoelectromechanical systems are hardly compatible with such transfer processes. Here, we introduce a methodology for obtaining thousands of microbeams, made of graphitized silicon carbide on silicon, through a site-selective and wafer-scale approach. A Ni-Cu alloy catalyst mediates a self-aligned graphitization on prepatterned SiC microstructures at a temperature that is compatible with silicon technologies. The graphene nanocoating leads to a dramatically enhanced electrical conductivity, which elevates this approach to an ideal method for the replacement of conductive metal films in silicon carbide-based MEMS and NEMS devices.

  1. Molecular Momentum Transport at Fluid-Solid Interfaces in MEMS/NEMS: A Review

    PubMed Central

    Cao, Bing-Yang; Sun, Jun; Chen, Min; Guo, Zeng-Yuan

    2009-01-01

    This review is focused on molecular momentum transport at fluid-solid interfaces mainly related to microfluidics and nanofluidics in micro-/nano-electro-mechanical systems (MEMS/NEMS). This broad subject covers molecular dynamics behaviors, boundary conditions, molecular momentum accommodations, theoretical and phenomenological models in terms of gas-solid and liquid-solid interfaces affected by various physical factors, such as fluid and solid species, surface roughness, surface patterns, wettability, temperature, pressure, fluid viscosity and polarity. This review offers an overview of the major achievements, including experiments, theories and molecular dynamics simulations, in the field with particular emphasis on the effects on microfluidics and nanofluidics in nanoscience and nanotechnology. In Section 1 we present a brief introduction on the backgrounds, history and concepts. Sections 2 and 3 are focused on molecular momentum transport at gas-solid and liquid-solid interfaces, respectively. Summary and conclusions are finally presented in Section 4. PMID:20087458

  2. Frictional Behavior of Micro/nanotextured Surfaces Investigated by Atomic Force Microscope: a Review

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoliang; Jia, Junhong

    2015-08-01

    Tribological issues between friction pair are fundamental problems for minimized devices because of their higher surface-to-volume ratio. Micro/nanotexturing is an effective technique to reduce actual contact area between contact pair at the nanoscale. Micro/nanotexture made a great impact on the frictional behavior of textured surfaces. This paper summarizes the recent advancements in the field of frictional behavior of micro/nanotextured surfaces, which are based on solid surface contact in atmosphere environment, especially focusing on the factors influencing the frictional behavior: Surface property, texturing density, texturing height, texturing structure and size of contact pair (atomic force microscope (AFM) tip) and texturing structures. Summarizing the effects of these factors on the frictional behavior is helpful for the understanding and designing of the surfaces in sliding micro/nanoelectromechanical systems (MEMS/NEMS). Controlling and reducing the friction force in moving mechanical systems is very important for the performance and reliability of nanosystems, which contribute to a sustainable future.

  3. Final Technical Report for Riedo Georgia Tech

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Riedo, Elisa

    Nanosheets, nanotubes, nanowires, and nanoparticles are gaining a large interest in the scientific community for their exciting properties, and they hold the potential to become building blocks in integrated nano-electronic and photonic circuits, nano-sensors, batteries electrodes, energy harvesting nano-systems, and nano-electro-mechanical systems (NEMS). While several experiments and theoretical calculations have revealed exciting novel phenomena in these nanostructures, many scientific and technological questions remain open. A fundamental objective guiding the study of nanoscale materials is understanding what are the new rules governing nanoscale properties and at what extent well-known physical macroscopic laws still apply in the nano-world. The vision of thismore » DoE research program is to understand the mechanical properties of nanoscale materials by exploring new experimental methods and theoretical models at the boundaries between continuum mechanics and atomistic models, with the overarching goal of defining the basic laws of mechanics at the nanoscale.« less

  4. The Flint Food Store Survey: combining spatial analysis with a modified Nutrition Environment Measures Survey in Stores (NEMS-S) to measure the community and consumer nutrition environments.

    PubMed

    Shaver, Erika R; Sadler, Richard C; Hill, Alex B; Bell, Kendall; Ray, Myah; Choy-Shin, Jennifer; Lerner, Joy; Soldner, Teresa; Jones, Andrew D

    2018-06-01

    The goal of the present study was to use a methodology that accurately and reliably describes the availability, price and quality of healthy foods at both the store and community levels using the Nutrition Environment Measures Survey in Stores (NEMS-S), to propose a spatial methodology for integrating these store and community data into measures for defining objective food access. Two hundred and sixty-five retail food stores in and within 2 miles (3·2 km) of Flint, Michigan, USA, were mapped using ArcGIS mapping software. A survey based on the validated NEMS-S was conducted at each retail food store. Scores were assigned to each store based on a modified version of the NEMS-S scoring system and linked to the mapped locations of stores. Neighbourhood characteristics (race and socio-economic distress) were appended to each store. Finally, spatial and kernel density analyses were run on the mapped store scores to obtain healthy food density metrics. Regression analyses revealed that neighbourhoods with higher socio-economic distress had significantly lower dairy sub-scores compared with their lower-distress counterparts (β coefficient=-1·3; P=0·04). Additionally, supermarkets were present only in neighbourhoods with <60 % African-American population and low socio-economic distress. Two areas in Flint had an overall NEMS-S score of 0. By identifying areas with poor access to healthy foods via a validated metric, this research can be used help local government and organizations target interventions to high-need areas. Furthermore, the methodology used for the survey and the mapping exercise can be replicated in other cities to provide comparable results.

  5. Nanoelectromechanical Chip (NELMEC) Combination of Nanoelectronics and Microfluidics to Diagnose Epithelial and Mesenchymal Circulating Tumor Cells from Leukocytes.

    PubMed

    Hosseini, Seied Ali; Abdolahad, Mohammad; Zanganeh, Somayeh; Dahmardeh, Mahyar; Gharooni, Milad; Abiri, Hamed; Alikhani, Alireza; Mohajerzadeh, Shams; Mashinchian, Omid

    2016-02-17

    An integrated nano-electromechanical chip (NELMEC) has been developed for the label-free distinguishing of both epithelial and mesenchymal circulating tumor cells (ECTCs and MCTCs, respectively) from white blood cells (WBCs). This nanoelectronic microfluidic chip fabricated by silicon micromachining can trap large single cells (>12 µm) at the opening of the analysis microchannel arrays. The nature of the captured cells is detected using silicon nanograss (SiNG) electrodes patterned at the entrance of the channels. There is an observable difference between the membrane capacitance of the ECTCs and MCTCs and that of WBCs (measured using SiNG electrodes), which is the key indication for our diagnosis. The NELMEC chip not only solves the problem of the size overlap between CTCs and WBCs but also detects MCTCs without the need for any markers or tagging processes, which has been an important problem in previously reported CTC detection systems. The great conductivity of the gold-coated SiNG nanocontacts as well as their safe penetration into the membrane of captured cells, facilitate a precise and direct signal extraction to distinguish the type of captured cell. The results achieved from epithelial (MCF-7) and mesenchymal (MDA-MB231) breast cancer cells circulated in unprocessed blood suggest the significant applications for these diagnostic abilities of NELMEC. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Design of photonic phased array switches using nano electromechanical systems on silicon-on-insulator integration platform

    NASA Astrophysics Data System (ADS)

    Hussein, Ali Abdulsattar

    This thesis presents an introduction to the design and simulation of a novel class of integrated photonic phased array switch elements. The main objective is to use nano-electromechanical (NEMS) based phase shifters of cascaded under-etched slot nanowires that are compact in size and require a small amount of power to operate them. The structure of the switch elements is organized such that it brings the phase shifting elements to the exterior sides of the photonic circuits. The transition slot couplers, used to interconnect the phase shifters, are designed to enable biasing one of the silicon beams of each phase shifter from an electrode located at the side of the phase shifter. The other silicon beam of each phase shifter is biased through the rest of the silicon structure of the switch element, which is taken as a ground. Phased array switch elements ranging from 2x2 up to 8x8 multiple-inputs/multiple-outputs (MIMO) are conveniently designed within reasonable footprints native to the current fabrication technologies. Chapter one presents the general layout of the various designs of the switch elements and demonstrates their novel features. This demonstration will show how waveguide disturbances in the interconnecting network from conventional switch elements can be avoided by adopting an innovative design. Some possible applications for the designed switch elements of different sizes and topologies are indicated throughout the chapter. Chapter two presents the design of the multimode interference (MMI) couplers used in the switch elements as splitters, combiners and waveguide crossovers. Simulation data and design methodologies for the multimode couplers of interest are detailed in this chapter. Chapter three presents the design and analysis of the NEMS-operated phase shifters. Both simulations and numerical analysis are utilized in the design of a 0°-180° capable NEMS-operated phase shifter. Additionally, the response of some of the designed photonic phased

  7. Structural and mechanical characterization of hybrid metallic-inorganic nanosprings

    NASA Astrophysics Data System (ADS)

    Habtoun, Sabrina; Houmadi, Said; Reig, Benjamin; Pouget, Emilie; Dedovets, Dmytro; Delville, Marie-Hélène; Oda, Reiko; Cristiano, Fuccio; Bergaud, Christian

    2017-10-01

    Silica nanosprings (NS) are fabricated by a sol-gel deposition of silica precursors onto a template made of self-assembled organic chiral nanostructures. They are deposited and assembled on microstructured silicon substrates, and then metallized and clamped in a single lithography-free step using a focused ion beam (FIB). The resulting suspended hybrid metallic/inorganic NS are then characterized with high-resolution transmission electron microscopy (HRTEM) and scanning TEM/energy-dispersive X-ray spectroscopy (STEM/EDX), showing the atomic structure of the metallic layer. Three-point bending tests are also carried out using an atomic force microscope (AFM) and supported by finite element method (FEM) simulation with COMSOL Multiphysics allowing the characterization of the mechanical behavior and the estimation of the stiffness of the resulting NS. The information obtained on the structural and mechanical properties of the NS is discussed for future nano-electro-mechanical system (NEMS) applications.

  8. Genetic and Physical Mapping of Meloidogyne Incognita Resistance on Chromosome 11 of Acala NemX Cotton.

    USDA-ARS?s Scientific Manuscript database

    Root-knot nematode (RKN, Meloidogyne incognita) resistance in Gossypium hirsutum ‘Acala NemX’ cotton is conferred by the recessive gene rkn1 (locus Mi2h-C11) on chromosome 11. The concentration of RKN, reniform nematode and other disease resistance determinants on chromosome 11 indicates that much c...

  9. The Implementation of NEMS GFS Aerosol Component (NGAC) Version 1.0 for Global Dust Forecasting at NOAA NCEP

    NASA Technical Reports Server (NTRS)

    Lu, Cheng-Hsuan; Da Silva, Arlindo M.; Wang, Jun; Moorthi, Shrinivas; Chin, Mian; Colarco, Peter; Tang, Youhua; Bhattacharjee, Partha S.; Chen, Shen-Po; Chuang, Hui-Ya; hide

    2016-01-01

    The NOAA National Centers for Environmental Prediction (NCEP) implemented the NOAA Environmental Modeling System (NEMS) Global Forecast System (GFS) Aerosol Component (NGAC) for global dust forecasting in collaboration with NASA Goddard Space Flight Center (GSFC). NGAC Version 1.0 has been providing 5-day dust forecasts at 1deg x 1deg resolution on a global scale, once per day at 00:00 Coordinated Universal Time (UTC), since September 2012. This is the first global system capable of interactive atmosphere aerosol forecasting at NCEP. The implementation of NGAC V1.0 reflects an effective and efficient transitioning of NASA research advances to NCEP operations, paving the way for NCEP to provide global aerosol products serving a wide range of stakeholders, as well as to allow the effects of aerosols on weather forecasts and climate prediction to be considered.

  10. Nutrition Environment Measures Survey in stores (NEMS-S): development and evaluation.

    PubMed

    Glanz, Karen; Sallis, James F; Saelens, Brian E; Frank, Lawrence D

    2007-04-01

    Eating, or nutrition, environments are believed to contribute to obesity and chronic diseases. There is a need for valid, reliable measures of nutrition environments. This article reports on the development and evaluation of measures of nutrition environments in retail food stores. The Nutrition Environment Measures Study developed observational measures of the nutrition environment within retail food stores (NEMS-S) to assess availability of healthy options, price, and quality. After pretesting, measures were completed by independent raters to evaluate inter-rater reliability and across two occasions to assess test-retest reliability in grocery and convenience stores in four neighborhoods differing on income and community design in the Atlanta metropolitan area. Data were collected and analyzed in 2004 and 2005. Ten food categories (e.g., fruits) or indicator food items (e.g., ground beef) were evaluated in 85 stores. Inter-rater reliability and test-retest reliability of availability were high: inter-rater reliability kappas were 0.84 to 1.00, and test-retest reliabilities were .73 to 1.00. Inter-rater reliability for quality across fresh produce was moderate (kappas, 0.44 to 1.00). Healthier options were higher priced for hot dogs, lean ground beef, and baked chips. More healthful options were available in grocery than convenience stores and in stores in higher income neighborhoods. The NEMS-S tool was found to have a high degree of inter-rater and test-retest reliability, and to reveal significant differences across store types and neighborhoods of high and low socioeconomic status. These observational measures of nutrition environments can be applied in multilevel studies of community nutrition, and can inform new approaches to conducting and evaluating nutrition interventions.

  11. Microchips and controlled-release drug reservoirs.

    PubMed

    Staples, Mark

    2010-01-01

    This review summarizes and updates the development of implantable microchip-containing devices that control dosing from drug reservoirs integrated with the devices. As the expense and risk of new drug development continues to increase, technologies that make the best use of existing therapeutics may add significant value. Trends of future medical care that may require advanced drug delivery systems include individualized therapy and the capability to automate drug delivery. Implantable drug delivery devices that promise to address these anticipated needs have been constructed in a variety of ways using micro- and nanoelectromechanical systems (MEMS or NEMS)-based technology. These devices expand treatment options for addressing unmet medical needs related to dosing. Within the last few years, advances in several technologies (MEMS or NEMS fabrication, materials science, polymer chemistry, and data management) have converged to enable the construction of miniaturized implantable devices for controlled delivery of therapeutic agents from one or more reservoirs. Suboptimal performance of conventional dosing methods in terms of safety, efficacy, pain, or convenience can be improved with advanced delivery devices. Microchip-based implantable drug delivery devices allow localized delivery by direct placement of the device at the treatment site, delivery on demand (emergency administration, pulsatile, or adjustable continuous dosing), programmable dosing cycles, automated delivery of multiple drugs, and dosing in response to physiological and diagnostic feedback. In addition, innovative drug-medical device combinations may protect labile active ingredients within hermetically sealed reservoirs. Copyright (c) 2010 John Wiley & Sons, Inc.

  12. Modelling of Piezothermoelastic Beam with Fractional Order Derivative

    NASA Astrophysics Data System (ADS)

    Kumar, Rajneesh; Sharma, Poonam

    2016-04-01

    This paper deals with the study of transverse vibrations in piezothermoelastic beam resonators with fractional order derivative. The fractional order theory of thermoelasticity developed by Sherief et al. [1] has been used to study the problem. The expressions for frequency shift and damping factor are derived for a thermo micro-electromechanical (MEM) and thermo nano-electromechanical (NEM) beam resonators clamped on one side and free on another. The effect of fractional order derivative on the derived expressions is observed analytically and shown graphically in the case of Lead Zirconate Titanate (PZT)-5A material. For α = 1, our results agree with those that are obtained by Grover and Sharma [20] and other particular cases of interest are also discussed.

  13. The resonant body transistor.

    PubMed

    Weinstein, Dana; Bhave, Sunil A

    2010-04-14

    This paper introduces the resonant body transistor (RBT), a silicon-based dielectrically transduced nanoelectromechanical (NEM) resonator embedding a sense transistor directly into the resonator body. Combining the benefits of FET sensing with the frequency scaling capabilities and high quality factors (Q) of internal dielectrically transduced bar resonators, the resonant body transistor achieves >10 GHz frequencies and can be integrated into a standard CMOS process for on-chip clock generation, high-Q microwave circuits, fundamental quantum-state preparation and observation, and high-sensitivity measurements. An 11.7 GHz bulk-mode RBT is demonstrated with a quality factor Q of 1830, marking the highest frequency acoustic resonance measured to date on a silicon wafer.

  14. Mechanism of Benzene Tribopolymerization on the RuO2 (110) Surface

    NASA Astrophysics Data System (ADS)

    Yang, J.; Qi, Y.; Kim, H. D.; Rappe, A. M.

    2018-04-01

    A tribopolymer formed on the contacts of microelectromechanical and nanoelectromechanical system (MEMS-NEMS) devices is a major concern hampering their practical use in information technology. Conductive metal oxides, such as RuO2 and ReO3 , have been regarded as promising candidate materials for MEMS-NEMS contacts due to their conductivity, hardness, and relatively chemically inert surfaces. However, recent experimental works demonstrate that trace amounts of a polymer could still form on RuO2 surfaces. We demonstrate the mechanism of this class of unexpected tribopolymer formation by conducting density-functional-theory-based computational compression experiments with benzene as the contamination gas. First, mechanical force during compression changes the benzene molecules from slightly physisorbed to strongly chemisorbed. Further compression causes deformation and chemical linkage of the benzene molecules. Finally, the two contacts detach, with one having a complex organic molecule attached and the other a more reactive surface. The complex organic molecule, which has an oxabicyclic segment, can be viewed as the rudiment of a tribopolymer, and the more reactive surface can trigger the next adsorption-reaction-tribopolymer formation cycle. Based on these results, we also predict tribopolymer formation rates by using transition-state theory and the second-order rate law. We promote a deeper understanding of tribopolymer formation (especially on metal oxides) and provide strategies for suppressing tribopolymerization.

  15. Dependence of the friction strengthening of graphene on velocity.

    PubMed

    Zeng, Xingzhong; Peng, Yitian; Liu, Lei; Lang, Haojie; Cao, Xing'an

    2018-01-25

    Graphene shows great potential applications as a solid lubricant in micro- and nanoelectromechanical systems (MEMS/NEMS). An atomic-scale friction strengthening effect in a few initial atomic friction periods usually occurred on few-layer graphene. Here, velocity dependent friction strengthening was observed in atomic-scale frictional behavior of graphene by atomic force microscopy (AFM). The degree of the friction strengthening decreases with the increase of velocity first and then reaches a plateau. This could be attributed to the interaction potential between the tip and graphene at high velocity which is weaker than that at low velocity, because the strong tip-graphene contact interface needs a longer time to evolve. The subatomic-scale stick-slip behavior in the conventional stick-slip motion supports the weak interaction between the tip and graphene at high velocity. These findings can provide a deeper understanding of the atomic-scale friction mechanism of graphene and other two-dimensional materials.

  16. Carbon Nanotube based Nanotechnolgy

    NASA Astrophysics Data System (ADS)

    Meyyappan, M.

    2000-10-01

    Carbon nanotube(CNT) was discovered in the early 1990s and is an off-spring of C60(the fullerene or buckyball). CNT, depending on chirality and diameter, can be metallic or semiconductor and thus allows formation of metal-semiconductor and semiconductor-semiconductor junctions. CNT exhibits extraordinary electrical and mechanical properties and offers remarkable potential for revolutionary applications in electronics devices, computing and data storage technology, sensors, composites, storage of hydrogen or lithium for battery development, nanoelectromechanical systems(NEMS), and as tip in scanning probe microscopy(SPM) for imaging and nanolithography. Thus the CNT synthesis, characterization and applications touch upon all disciplines of science and engineering. A common growth method now is based on CVD though surface catalysis is key to synthesis, in contrast to many CVD applications common in microelectronics. A plasma based variation is gaining some attention. This talk will provide an overview of CNT properties, growth methods, applications, and research challenges and opportunities ahead.

  17. The National energy modeling system

    NASA Astrophysics Data System (ADS)

    The DOE uses a variety of energy and economic models to forecast energy supply and demand. It also uses a variety of more narrowly focussed analytical tools to examine energy policy options. For the purpose of the scope of this work, this set of models and analytical tools is called the National Energy Modeling System (NEMS). The NEMS is the result of many years of development of energy modeling and analysis tools, many of which were developed for different applications and under different assumptions. As such, NEMS is believed to be less than satisfactory in certain areas. For example, NEMS is difficult to keep updated and expensive to use. Various outputs are often difficult to reconcile. Products were not required to interface, but were designed to stand alone. Because different developers were involved, the inner workings of the NEMS are often not easily or fully understood. Even with these difficulties, however, NEMS comprises the best tools currently identified to deal with our global, national and regional energy modeling, and energy analysis needs.

  18. The implementation of NEMS GFS Aerosol Component (NGAC) Version 1.0 for global dust forecasting at NOAA/NCEP

    PubMed Central

    Lu, Cheng-Hsuan; da Silva, Arlindo; Wang, Jun; Moorthi, Shrinivas; Chin, Mian; Colarco, Peter; Tang, Youhua; Bhattacharjee, Partha S.; Chen, Shen-Po; Chuang, Hui-Ya; Juang, Hann-Ming Henry; McQueen, Jeffery; Iredell, Mark

    2018-01-01

    The NOAA National Centers for Environmental Prediction (NCEP) implemented NEMS GFS Aerosol Component (NGAC) for global dust forecasting in collaboration with NASA Goddard Space Flight Center (GSFC). NGAC Version 1.0 has been providing 5 day dust forecasts at 1°×1° resolution on a global scale, once per day at 00:00 Coordinated Universal Time (UTC), since September 2012. This is the first global system capable of interactive atmosphere aerosol forecasting at NCEP. The implementation of NGAC V1.0 reflects an effective and efficient transitioning of NASA research advances to NCEP operations, paving the way for NCEP to provide global aerosol products serving a wide range of stakeholders as well as to allow the effects of aerosols on weather forecasts and climate prediction to be considered. PMID:29652411

  19. The implementation of NEMS GFS Aerosol Component (NGAC) Version 1.0 for global dust forecasting at NOAA/NCEP.

    PubMed

    Lu, Cheng-Hsuan; da Silva, Arlindo; Wang, Jun; Moorthi, Shrinivas; Chin, Mian; Colarco, Peter; Tang, Youhua; Bhattacharjee, Partha S; Chen, Shen-Po; Chuang, Hui-Ya; Juang, Hann-Ming Henry; McQueen, Jeffery; Iredell, Mark

    2016-01-01

    The NOAA National Centers for Environmental Prediction (NCEP) implemented NEMS GFS Aerosol Component (NGAC) for global dust forecasting in collaboration with NASA Goddard Space Flight Center (GSFC). NGAC Version 1.0 has been providing 5 day dust forecasts at 1°×1° resolution on a global scale, once per day at 00:00 Coordinated Universal Time (UTC), since September 2012. This is the first global system capable of interactive atmosphere aerosol forecasting at NCEP. The implementation of NGAC V1.0 reflects an effective and efficient transitioning of NASA research advances to NCEP operations, paving the way for NCEP to provide global aerosol products serving a wide range of stakeholders as well as to allow the effects of aerosols on weather forecasts and climate prediction to be considered.

  20. Model documentation, Coal Market Module of the National Energy Modeling System

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    NONE

    This report documents the objectives and the conceptual and methodological approach used in the development of the National Energy Modeling System`s (NEMS) Coal Market Module (CMM) used to develop the Annual Energy Outlook 1998 (AEO98). This report catalogues and describes the assumptions, methodology, estimation techniques, and source code of CMM`s two submodules. These are the Coal Production Submodule (CPS) and the Coal Distribution Submodule (CDS). CMM provides annual forecasts of prices, production, and consumption of coal for NEMS. In general, the CDS integrates the supply inputs from the CPS to satisfy demands for coal from exogenous demand models. The internationalmore » area of the CDS forecasts annual world coal trade flows from major supply to major demand regions and provides annual forecasts of US coal exports for input to NEMS. Specifically, the CDS receives minemouth prices produced by the CPS, demand and other exogenous inputs from other NEMS components, and provides delivered coal prices and quantities to the NEMS economic sectors and regions.« less

  1. Energy harvesting: an integrated view of materials, devices and applications.

    PubMed

    Radousky, H B; Liang, H

    2012-12-21

    Energy harvesting refers to the set of processes by which useful energy is captured from waste, environmental, or mechanical sources and is converted into a usable form. The discipline of energy harvesting is a broad topic that includes established methods and materials such as photovoltaics and thermoelectrics, as well as more recent technologies that convert mechanical energy, magnetic energy and waste heat to electricity. This article will review various state-of-the-art materials and devices for direct energy conversion and in particular will include multistep energy conversion approaches. The article will highlight the nano-materials science underlying energy harvesting principles and devices, but also include more traditional bulk processes and devices as appropriate and synergistic. Emphasis is placed on device-design innovations that lead to higher efficiency energy harvesting or conversion technologies ranging from the cm/mm-scale down to MEMS/NEMS (micro- and nano-electromechanical systems) devices. Theoretical studies are reviewed, which address transport properties, crystal chemistry, thermodynamic analysis, energy transfer, system efficiency and device operation. New developments in experimental methods; device design and fabrication; nanostructured materials fabrication; materials properties; and device performance measurement techniques are discussed.

  2. About “SI” Traceability of Micromasses And/or Microforces

    NASA Astrophysics Data System (ADS)

    Vâlcu, Adriana; Ştefănescu, Dan Mihai

    Over the last period, increasing attention has been paid to measurement of small forces which play a more important role in nanotechnology and other significant areas such as MEMS (Micro-Electro-Mechanical Systems) and NEMS (nano-electro-mechanical systems) which can be found into everyday products (mobile phones, MP3 players, PCs, cars). In this respect, the development of mass standards and measurement techniques below the current limit of 1 milligram is vital to provide traceability to the SI for such measurements. In Romania, the Mass laboratory of INM considered it necessary to extend the dissemination of the mass unit below 1 mg, in order to meet current needs. Using the subdivision method and starting from the national prototype kilogram No. 2, all necessary experiments were performed for the first time in Romania to extend mass unit traceability till 100 μg. This extension also supports the provision of mass calibrations for low force measurements. The associated measurement procedure and measurement uncertainty results obtained in the calibration are described. In the article are also presented some of the worldwide methods currently used for measuring small forces.

  3. Latest advances in the manufacturing of 3D rechargeable lithium microbatteries

    NASA Astrophysics Data System (ADS)

    Ferrari, Stefania; Loveridge, Melanie; Beattie, Shane D.; Jahn, Marcus; Dashwood, Richard J.; Bhagat, Rohit

    2015-07-01

    Recent advances in micro- and nano-electromechanical systems (MEMS/NEMS) technology have led to a niche industry of diverse small-scale devices that include microsensors, micromachines and drug-delivery systems. For these devices, there is an urgent need to develop Micro Lithium Ion Batteries (MLIBs) with dimensions on the scale 1-10 mm3 enabling on-board power delivery. Unfortunately, power limitations are inherent in planar 2D cells and only the advent of 3D designs and microarchitectures will lead to a real breakthrough in the microbattery technology. During the last few years, many efforts to optimise MLIBs were discussed in literature, both in the planar and 3D configurations. This review highlights the importance of 3D microarchitectured electrodes to fabricate batteries that can be device-integrated with exceptionally high specific power density coupled with exquisite miniaturisation. A wide literature overview is provided and recent advances in manufacturing routes to 3D-MLIBs comprising materials synthesis, device formulation, device testing are herein discussed. The advent of simple, economic and easily scalable fabrication processes such as 3D printing will have a decisive role in the growing field of micropower sources and microdevices.

  4. Energy harvesting: an integrated view of materials, devices and applications

    NASA Astrophysics Data System (ADS)

    Radousky, H. B.; Liang, H.

    2012-12-01

    Energy harvesting refers to the set of processes by which useful energy is captured from waste, environmental, or mechanical sources and is converted into a usable form. The discipline of energy harvesting is a broad topic that includes established methods and materials such as photovoltaics and thermoelectrics, as well as more recent technologies that convert mechanical energy, magnetic energy and waste heat to electricity. This article will review various state-of-the-art materials and devices for direct energy conversion and in particular will include multistep energy conversion approaches. The article will highlight the nano-materials science underlying energy harvesting principles and devices, but also include more traditional bulk processes and devices as appropriate and synergistic. Emphasis is placed on device-design innovations that lead to higher efficiency energy harvesting or conversion technologies ranging from the cm/mm-scale down to MEMS/NEMS (micro- and nano-electromechanical systems) devices. Theoretical studies are reviewed, which address transport properties, crystal chemistry, thermodynamic analysis, energy transfer, system efficiency and device operation. New developments in experimental methods; device design and fabrication; nanostructured materials fabrication; materials properties; and device performance measurement techniques are discussed.

  5. Investigating Alkylsilane Monolayer Tribology at a Single-Asperity Contact with Molecular Dynamics Simulation.

    PubMed

    Summers, Andrew Z; Iacovella, Christopher R; Cummings, Peter T; McCabe, Clare

    2017-10-24

    Chemisorbed monolayer films are known to possess favorable characteristics for nanoscale lubrication of micro- and nanoelectromechanical systems (MEMS/NEMS). Prior studies have shown that the friction observed for monolayer-coated surfaces features a strong dependence on the geometry of contact. Specifically, tip-like geometries have been shown to penetrate into monolayer films, inducing defects in the monolayer chains and leading to plowing mechanisms during shear, which result in higher coefficients of friction (COF) than those observed for planar geometries. In this work, we use molecular dynamics simulations to examine the tribology of model silica single-asperity contacts under shear with monolayer-coated substrates featuring various film densities. It is observed that lower monolayer densities lead to reduced COFs, in contrast to results for planar systems where COF is found to be nearly independent of monolayer density. This is attributed to a liquid-like response to shear, whereby fewer defects are imparted in monolayer chains from the asperity, and chains are easily displaced by the tip as a result of the higher free volume. This transition in the mechanism of molecular plowing suggests that liquid-like films should provide favorable lubrication at single-asperity contacts.

  6. Hexagonal boron nitride nanomechanical resonators with spatially visualized motion

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zheng, Xu-Qian; Lee, Jaesung; Feng, Philip X. -L.

    Atomic layers of hexagonal boron nitride (h-BN) crystal are excellent candidates for structural materials as enabling ultrathin, two-dimensional (2D) nanoelectromechanical systems (NEMS) due to the outstanding mechanical properties and very wide bandgap (5.9 eV) of h-BN. In this work, we report the experimental demonstration of h-BN 2D nanomechanical resonators vibrating at high and very high frequencies (from ~ 5 to ~ 70 MHz), and investigations of the elastic properties of h-BN by measuring the multimode resonant behavior of these devices. First, we demonstrate a dry-transferred doubly clamped h-BN membrane with ~ 6.7 nm thickness, the thinnest h-BN resonator known tomore » date. In addition, we fabricate circular drumhead h-BN resonators with thicknesses ranging from ~ 9 to 292 nm, from which we measure up to eight resonance modes in the range of ~ 18 to 35 MHz. Combining measurements and modeling of the rich multimode resonances, we resolve h-BN’s elastic behavior, including the transition from membrane to disk regime, with built-in tension ranging from 0.02 to 2 N m -1. The Young’s modulus of h-BN is determined to be EY≈392 GPa from the measured resonances. The ultrasensitive measurements further reveal subtle structural characteristics and mechanical properties of the suspended h-BN diaphragms, including anisotropic built-in tension and bulging, thus suggesting guidelines on how these effects can be exploited for engineering multimode resonant functions in 2D NEMS transducers.« less

  7. Hexagonal boron nitride nanomechanical resonators with spatially visualized motion

    DOE PAGES

    Zheng, Xu-Qian; Lee, Jaesung; Feng, Philip X. -L.

    2017-07-31

    Atomic layers of hexagonal boron nitride (h-BN) crystal are excellent candidates for structural materials as enabling ultrathin, two-dimensional (2D) nanoelectromechanical systems (NEMS) due to the outstanding mechanical properties and very wide bandgap (5.9 eV) of h-BN. In this work, we report the experimental demonstration of h-BN 2D nanomechanical resonators vibrating at high and very high frequencies (from ~ 5 to ~ 70 MHz), and investigations of the elastic properties of h-BN by measuring the multimode resonant behavior of these devices. First, we demonstrate a dry-transferred doubly clamped h-BN membrane with ~ 6.7 nm thickness, the thinnest h-BN resonator known tomore » date. In addition, we fabricate circular drumhead h-BN resonators with thicknesses ranging from ~ 9 to 292 nm, from which we measure up to eight resonance modes in the range of ~ 18 to 35 MHz. Combining measurements and modeling of the rich multimode resonances, we resolve h-BN’s elastic behavior, including the transition from membrane to disk regime, with built-in tension ranging from 0.02 to 2 N m -1. The Young’s modulus of h-BN is determined to be EY≈392 GPa from the measured resonances. The ultrasensitive measurements further reveal subtle structural characteristics and mechanical properties of the suspended h-BN diaphragms, including anisotropic built-in tension and bulging, thus suggesting guidelines on how these effects can be exploited for engineering multimode resonant functions in 2D NEMS transducers.« less

  8. Assessment of nanosystems for space applications

    NASA Astrophysics Data System (ADS)

    Bilhaut, Lise; Duraffourg, Laurent

    2009-11-01

    This paper first gives an overview of the applications of micro-electro-mechanical systems (MEMS) in space. Microsystems are advertised for their extremely low size and mass, along with their low power consumption and in some case their improved performances. Examples of actual flown MEMS and future missions relying on MEMS are given. Microsystems are now enjoying a dynamic and expanding interest in the space community. This paper intends to give an idea about the next step in miniaturization, since the microelectronic industry is already looking at nano-electro-mechanical systems (NEMS) driven by the more-than-Moore philosophy. We show that the impact of nanosystems should not be reduced at a homothecy in size, weight and power consumption. New forces appear at this scale (Casimir force…) which have to be considered in the system design. The example of a nano-mechanical memory is developed. We also show that performances of nanosystems are not systematically better than their microscopic counterparts through the study of the impact of dimension reduction on an accelerometer resolution and sensitivity. We conclude with the idea that nanosystems will find their greatest applications in distributed intelligent networks that will allow new mission concepts for space exploration.

  9. Graphitization in Carbon MEMS and Carbon NEMS

    NASA Astrophysics Data System (ADS)

    Sharma, Swati

    Carbon MEMS (CMEMS) and Carbon NEMS (CNEMS) are an emerging class of miniaturized devices. Due to the numerous advantages such as scalable manufacturing processes, inexpensive and readily available precursor polymer materials, tunable surface properties and biocompatibility, carbon has become a preferred material for a wide variety of future sensing applications. Single suspended carbon nanowires (CNWs) integrated on CMEMS structures fabricated by electrospinning of SU8 photoresist on photolithographially patterned SU8 followed by pyrolysis are utilized for understanding the graphitization process in micro and nano carbon materials. These monolithic CNW-CMEMS structures enable the fabrication of very high aspect ratio CNWs of predefined length. The CNWs thus fabricated display core---shell structures having a graphitic shell with a glassy carbon core. The electrical conductivity of these CNWs is increased by about 100% compared to glassy carbon as a result of enhanced graphitization. We explore various tunable fabrication and pyrolysis parameters to improve graphitization in the resulting CNWs. We also suggest gas-sensing application of the thus fabricated single suspended CNW-CMEMS devices by using the CNW as a nano-hotplate for local chemical vapor deposition. In this thesis we also report on results from an optimization study of SU8 photoresist derived carbon electrodes. These electrodes were applied to the simultaneous detection of traces of Cd(II) and Pb(II) through anodic stripping voltammetry and detection limits as low as 0.7 and 0.8 microgL-1 were achieved. To further improve upon the electrochemical behavior of the carbon electrodes we elucidate a modified pyrolysis technique featuring an ultra-fast temperature ramp for obtaining bubbled porous carbon from lithographically patterned SU8. We conclude this dissertation by suggesting the possible future works on enhancing graphitization as well as on electrochemical applications

  10. Electrodeposited Ni-Based Magnetic Mesoporous Films as Smart Surfaces for Atomic Layer Deposition: An "All-Chemical" Deposition Approach toward 3D Nanoengineered Composite Layers.

    PubMed

    Zhang, Jin; Quintana, Alberto; Menéndez, Enric; Coll, Mariona; Pellicer, Eva; Sort, Jordi

    2018-05-02

    Mesoporous Ni and Cu-Ni (Cu 20 Ni 80 and Cu 45 Ni 55 in at. %) films, showing a three-dimensional (3D) porous structure and tunable magnetic properties, are prepared by electrodeposition from aqueous surfactant solutions using micelles of P-123 triblock copolymer as structure-directing entities. Pores between 5 and 30 nm and dissimilar space arrangements (continuous interconnected networks, circular pores, corrugated mesophases) are obtained depending on the synthetic conditions. X-ray diffraction studies reveal that the Cu-Ni films have crystallized in the face-centered cubic structure, are textured, and exhibit certain degree of phase separation, particularly those with a higher Cu content. Atomic layer deposition (ALD) is used to conformally coat the mesopores of Cu 20 Ni 80 film with amorphous Al 2 O 3 , rendering multiphase "nano-in-meso" metal-ceramic composites without compromising the ferromagnetic response of the metallic scaffold. From a technological viewpoint, these 3D nanoengineered composite films could be appealing for applications like magnetically actuated micro/nanoelectromechanical systems (MEMS/NEMS), voltage-driven magneto-electric devices, capacitors, or as protective coatings with superior strength and tribological performance.

  11. Size dependent nanomechanics of coil spring shaped polymer nanowires

    NASA Astrophysics Data System (ADS)

    Ushiba, Shota; Masui, Kyoko; Taguchi, Natsuo; Hamano, Tomoki; Kawata, Satoshi; Shoji, Satoru

    2015-11-01

    Direct laser writing (DLW) via two-photon polymerization (TPP) has been established as a powerful technique for fabrication and integration of nanoscale components, as it enables the production of three dimensional (3D) micro/nano objects. This technique has indeed led to numerous applications, including micro- and nanoelectromechanical systems (MEMS/NEMS), metamaterials, mechanical metamaterials, and photonic crystals. However, as the feature sizes decrease, an urgent demand has emerged to uncover the mechanics of nanosized polymer materials. Here, we fabricate coil spring shaped polymer nanowires using DLW via two-photon polymerization. We find that even the nanocoil springs follow a linear-response against applied forces, following Hooke’s law, as revealed by compression tests using an atomic force microscope. Further, the elasticity of the polymer material is found to become significantly greater as the wire radius is decreased from 550 to 350 nm. Polarized Raman spectroscopy measurements show that polymer chains are aligned in nanowires along the axis, which may be responsible for the size dependence. Our findings provide insight into the nanomechanics of polymer materials fabricated by DLW, which leads to further applications based on nanosized polymer materials.

  12. Size dependent nanomechanics of coil spring shaped polymer nanowires.

    PubMed

    Ushiba, Shota; Masui, Kyoko; Taguchi, Natsuo; Hamano, Tomoki; Kawata, Satoshi; Shoji, Satoru

    2015-11-27

    Direct laser writing (DLW) via two-photon polymerization (TPP) has been established as a powerful technique for fabrication and integration of nanoscale components, as it enables the production of three dimensional (3D) micro/nano objects. This technique has indeed led to numerous applications, including micro- and nanoelectromechanical systems (MEMS/NEMS), metamaterials, mechanical metamaterials, and photonic crystals. However, as the feature sizes decrease, an urgent demand has emerged to uncover the mechanics of nanosized polymer materials. Here, we fabricate coil spring shaped polymer nanowires using DLW via two-photon polymerization. We find that even the nanocoil springs follow a linear-response against applied forces, following Hooke's law, as revealed by compression tests using an atomic force microscope. Further, the elasticity of the polymer material is found to become significantly greater as the wire radius is decreased from 550 to 350 nm. Polarized Raman spectroscopy measurements show that polymer chains are aligned in nanowires along the axis, which may be responsible for the size dependence. Our findings provide insight into the nanomechanics of polymer materials fabricated by DLW, which leads to further applications based on nanosized polymer materials.

  13. Size dependent nanomechanics of coil spring shaped polymer nanowires

    PubMed Central

    Ushiba, Shota; Masui, Kyoko; Taguchi, Natsuo; Hamano, Tomoki; Kawata, Satoshi; Shoji, Satoru

    2015-01-01

    Direct laser writing (DLW) via two-photon polymerization (TPP) has been established as a powerful technique for fabrication and integration of nanoscale components, as it enables the production of three dimensional (3D) micro/nano objects. This technique has indeed led to numerous applications, including micro- and nanoelectromechanical systems (MEMS/NEMS), metamaterials, mechanical metamaterials, and photonic crystals. However, as the feature sizes decrease, an urgent demand has emerged to uncover the mechanics of nanosized polymer materials. Here, we fabricate coil spring shaped polymer nanowires using DLW via two-photon polymerization. We find that even the nanocoil springs follow a linear-response against applied forces, following Hooke’s law, as revealed by compression tests using an atomic force microscope. Further, the elasticity of the polymer material is found to become significantly greater as the wire radius is decreased from 550 to 350 nm. Polarized Raman spectroscopy measurements show that polymer chains are aligned in nanowires along the axis, which may be responsible for the size dependence. Our findings provide insight into the nanomechanics of polymer materials fabricated by DLW, which leads to further applications based on nanosized polymer materials. PMID:26612544

  14. Distributed generation capabilities of the national energy modeling system

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    LaCommare, Kristina Hamachi; Edwards, Jennifer L.; Marnay, Chris

    2003-01-01

    This report describes Berkeley Lab's exploration of how the National Energy Modeling System (NEMS) models distributed generation (DG) and presents possible approaches for improving how DG is modeled. The on-site electric generation capability has been available since the AEO2000 version of NEMS. Berkeley Lab has previously completed research on distributed energy resources (DER) adoption at individual sites and has developed a DER Customer Adoption Model called DER-CAM. Given interest in this area, Berkeley Lab set out to understand how NEMS models small-scale on-site generation to assess how adequately DG is treated in NEMS, and to propose improvements or alternatives. Themore » goal is to determine how well NEMS models the factors influencing DG adoption and to consider alternatives to the current approach. Most small-scale DG adoption takes place in the residential and commercial modules of NEMS. Investment in DG ultimately offsets purchases of electricity, which also eliminates the losses associated with transmission and distribution (T&D). If the DG technology that is chosen is photovoltaics (PV), NEMS assumes renewable energy consumption replaces the energy input to electric generators. If the DG technology is fuel consuming, consumption of fuel in the electric utility sector is replaced by residential or commercial fuel consumption. The waste heat generated from thermal technologies can be used to offset the water heating and space heating energy uses, but there is no thermally activated cooling capability. This study consists of a review of model documentation and a paper by EIA staff, a series of sensitivity runs performed by Berkeley Lab that exercise selected DG parameters in the AEO2002 version of NEMS, and a scoping effort of possible enhancements and alternatives to NEMS current DG capabilities. In general, the treatment of DG in NEMS is rudimentary. The penetration of DG is determined by an economic cash-flow analysis that determines adoption based

  15. High-Throughput Top-Down and Bottom-Up Processes for Forming Single-Nanotube Based Architectures for 3D Electronics

    NASA Technical Reports Server (NTRS)

    Kaul, Anupama B.; Megerian, Krikor G.; von Allmen, Paul; Kowalczyk, Robert; Baron, Richard

    2009-01-01

    We have developed manufacturable approaches to form single, vertically aligned carbon nanotubes, where the tubes are centered precisely, and placed within a few hundred nm of 1-1.5 micron deep trenches. These wafer-scale approaches were enabled by chemically amplified resists and inductively coupled Cryo-etchers for forming the 3D nanoscale architectures. The tube growth was performed using dc plasma-enhanced chemical vapor deposition (PECVD), and the materials used for the pre-fabricated 3D architectures were chemically and structurally compatible with the high temperature (700 C) PECVD synthesis of our tubes, in an ammonia and acetylene ambient. Tube characteristics were also engineered to some extent, by adjusting growth parameters, such as Ni catalyst thickness, pressure and plasma power during growth. Such scalable, high throughput top-down fabrication techniques, combined with bottom-up tube synthesis, should accelerate the development of PECVD tubes for applications such as interconnects, nano-electromechanical (NEMS), sensors or 3D electronics in general.

  16. Nanoporous Silicon Carbide for Nanoelectromechanical Systems Applications

    NASA Technical Reports Server (NTRS)

    Hossain, T.; Khan, F.; Adesida, I.; Bohn, P.; Rittenhouse, T.; Lienhard, Michael (Technical Monitor)

    2003-01-01

    A major goal of this project is to produce porous silicon carbide (PSiC) via an electroless process for eventual utilization in nanoscale sensing platforms. Results in the literature have shown a variety of porous morphologies in SiC produced in anodic cells. Therefore, predictability and reproducibility of porous structures are initial concerns. This work has concentrated on producing morphologies of known porosity, with particular attention paid toward producing the extremely high surface areas required for a porous flow sensor. We have conducted a parametric study of electroless etching conditions and characteristics of the resulting physical nanostructure and also investigated the relationship between morphology and materials properties. Further, we have investigated bulk etching of SiC using both photo-electrochemical etching and inductively-coupled-plasma reactive ion etching techniques.

  17. Electromechanical oscillations in bilayer graphene

    PubMed Central

    Benameur, Muhammed M.; Gargiulo, Fernando; Manzeli, Sajedeh; Autès, Gabriel; Tosun, Mahmut; Yazyev, Oleg V.; Kis, Andras

    2015-01-01

    Nanoelectromechanical systems constitute a class of devices lying at the interface between fundamental research and technological applications. Realizing nanoelectromechanical devices based on novel materials such as graphene allows studying their mechanical and electromechanical characteristics at the nanoscale and addressing fundamental questions such as electron–phonon interaction and bandgap engineering. In this work, we realize electromechanical devices using single and bilayer graphene and probe the interplay between their mechanical and electrical properties. We show that the deflection of monolayer graphene nanoribbons results in a linear increase in their electrical resistance. Surprisingly, we observe oscillations in the electromechanical response of bilayer graphene. The proposed theoretical model suggests that these oscillations arise from quantum mechanical interference in the transition region induced by sliding of individual graphene layers with respect to each other. Our work shows that bilayer graphene conceals unexpectedly rich and novel physics with promising potential in applications based on nanoelectromechanical systems. PMID:26481767

  18. Vertically aligned carbon nanofibers and related structures: Controlled synthesis and directed assembly

    NASA Astrophysics Data System (ADS)

    Melechko, A. V.; Merkulov, V. I.; McKnight, T. E.; Guillorn, M. A.; Klein, K. L.; Lowndes, D. H.; Simpson, M. L.

    2005-02-01

    The controlled synthesis of materials by methods that permit their assembly into functional nanoscale structures lies at the crux of the emerging field of nanotechnology. Although only one of several materials families is of interest, carbon-based nanostructured materials continue to attract a disproportionate share of research effort, in part because of their wide-ranging properties. Additionally, developments of the past decade in the controlled synthesis of carbon nanotubes and nanofibers have opened additional possibilities for their use as functional elements in numerous applications. Vertically aligned carbon nanofibers (VACNFs) are a subclass of carbon nanostructured materials that can be produced with a high degree of control using catalytic plasma-enhanced chemical-vapor deposition (C-PECVD). Using C-PECVD the location, diameter, length, shape, chemical composition, and orientation can be controlled during VACNF synthesis. Here we review the CVD and PECVD systems, growth control mechanisms, catalyst preparation, resultant carbon nanostructures, and VACNF properties. This is followed by a review of many of the application areas for carbon nanotubes and nanofibers including electron field-emission sources, electrochemical probes, functionalized sensor elements, scanning probe microscopy tips, nanoelectromechanical systems (NEMS), hydrogen and charge storage, and catalyst support. We end by noting gaps in the understanding of VACNF growth mechanisms and the challenges remaining in the development of methods for an even more comprehensive control of the carbon nanofiber synthesis process.

  19. To develop a regional ICU mortality prediction model during the first 24 h of ICU admission utilizing MODS and NEMS with six other independent variables from the Critical Care Information System (CCIS) Ontario, Canada.

    PubMed

    Kao, Raymond; Priestap, Fran; Donner, Allan

    2016-01-01

    Intensive care unit (ICU) scoring systems or prediction models evolved to meet the desire of clinical and administrative leaders to assess the quality of care provided by their ICUs. The Critical Care Information System (CCIS) is province-wide data information for all Ontario, Canada level 3 and level 2 ICUs collected for this purpose. With the dataset, we developed a multivariable logistic regression ICU mortality prediction model during the first 24 h of ICU admission utilizing the explanatory variables including the two validated scores, Multiple Organs Dysfunctional Score (MODS) and Nine Equivalents Nursing Manpower Use Score (NEMS) followed by the variables age, sex, readmission to the ICU during the same hospital stay, admission diagnosis, source of admission, and the modified Charlson Co-morbidity Index (CCI) collected through the hospital health records. This study is a single-center retrospective cohort review of 8822 records from the Critical Care Trauma Centre (CCTC) and Medical-Surgical Intensive Care Unit (MSICU) of London Health Sciences Centre (LHSC), Ontario, Canada between 1 Jan 2009 to 30 Nov 2012. Multivariable logistic regression on training dataset (n = 4321) was used to develop the model and validate by bootstrapping method on the testing dataset (n = 4501). Discrimination, calibration, and overall model performance were also assessed. The predictors significantly associated with ICU mortality included: age (p < 0.001), source of admission (p < 0.0001), ICU admitting diagnosis (p < 0.0001), MODS (p < 0.0001), and NEMS (p < 0.0001). The variables sex and modified CCI were not significantly associated with ICU mortality. The training dataset for the developed model has good discriminating ability between patients with high risk and those with low risk of mortality (c-statistic 0.787). The Hosmer and Lemeshow goodness-of-fit test has a strong correlation between the observed and expected ICU mortality (χ (2) = 5

  20. High voltage generation from lead-free magnetoelectric coaxial nanotube arrays and their applications in nano energy harvesters.

    PubMed

    Lekha, C S Chitra; Kumar, Ajith S; Vivek, S; Rasi, U P Mohammed; Saravanan, K Venkata; Nandakumar, K; Nair, Swapna S

    2017-02-03

    Harvesting energy from surrounding vibrations and developing self-powered portable devices for wireless and mobile electronics have recently become popular. Here the authors demonstrate the synthesis of piezoelectric energy harvesters based on nanotube arrays by a wet chemical route, which requires no sophisticated instruments. The energy harvester gives an output voltage of 400 mV. Harvesting energy from a sinusoidal magnetic field is another interesting phenomenon for which the authors fabricated a magnetoelectric energy harvester based on piezoelectric-magnetostrictive coaxial nanotube arrays. Piezoelectric K 0.5 Na 0.5 NbO 3 (KNN) is fabricated as the shell and magnetostrictive CoFe 2 O 4 (CFO) as the core of the composite coaxial nanotubes. The delivered voltages are as high as 300 mV at 500 Hz and at a weak ac magnetic field of 100 Oe. Further tailoring of the thickness of the piezoelectric and magnetic layers can enhance the output voltage by several orders. Easy, single-step wet chemical synthesis enhances the industrial upscaling potential of these nanotubes as energy harvesters. In view of the excellent properties reported here, the lead-free piezoelectric component (KNN) in this nanocomposite should be explored for eco-friendly piezoelectric as well as magnetoelectric power generators in nanoelectromechanical systems (NEMS).

  1. Recent advances in molecular electronics based on carbon nanotubes.

    PubMed

    Bourgoin, Jean-Philippe; Campidelli, Stéphane; Chenevier, Pascale; Derycke, Vincent; Filoramo, Arianna; Goffman, Marcelo F

    2010-01-01

    Carbon nanotubes (CNTs) have exceptional physical properties that make them one of the most promising building blocks for future nanotechnologies. They may in particular play an important role in the development of innovative electronic devices in the fields of flexible electronics, ultra-high sensitivity sensors, high frequency electronics, opto-electronics, energy sources and nano-electromechanical systems (NEMS). Proofs of concept of several high performance devices already exist, usually at the single device level, but there remain many serious scientific issues to be solved before the viability of such routes can be evaluated. In particular, the main concern regards the controlled synthesis and positioning of nanotubes. In our opinion, truly innovative use of these nano-objects will come from: (i) the combination of some of their complementary physical properties, such as combining their electrical and mechanical properties, (ii) the combination of their properties with additional benefits coming from other molecules grafted on the nanotubes, and (iii) the use of chemically- or bio-directed self-assembly processes to allow the efficient combination of several devices into functional arrays or circuits. In this article, we outline the main issues concerning the development of carbon nanotubes based electronics applications and review our recent results in the field.

  2. High voltage generation from lead-free magnetoelectric coaxial nanotube arrays and their applications in nano energy harvesters

    NASA Astrophysics Data System (ADS)

    Lekha, C. S. Chitra; Kumar, Ajith S.; Vivek, S.; Rasi, U. P. Mohammed; Venkata Saravanan, K.; Nandakumar, K.; Nair, Swapna S.

    2017-02-01

    Harvesting energy from surrounding vibrations and developing self-powered portable devices for wireless and mobile electronics have recently become popular. Here the authors demonstrate the synthesis of piezoelectric energy harvesters based on nanotube arrays by a wet chemical route, which requires no sophisticated instruments. The energy harvester gives an output voltage of 400 mV. Harvesting energy from a sinusoidal magnetic field is another interesting phenomenon for which the authors fabricated a magnetoelectric energy harvester based on piezoelectric-magnetostrictive coaxial nanotube arrays. Piezoelectric K0.5Na0.5NbO3 (KNN) is fabricated as the shell and magnetostrictive CoFe2O4 (CFO) as the core of the composite coaxial nanotubes. The delivered voltages are as high as 300 mV at 500 Hz and at a weak ac magnetic field of 100 Oe. Further tailoring of the thickness of the piezoelectric and magnetic layers can enhance the output voltage by several orders. Easy, single-step wet chemical synthesis enhances the industrial upscaling potential of these nanotubes as energy harvesters. In view of the excellent properties reported here, the lead-free piezoelectric component (KNN) in this nanocomposite should be explored for eco-friendly piezoelectric as well as magnetoelectric power generators in nanoelectromechanical systems (NEMS).

  3. Growth temperature modulated phase evolution and functional characteristics of high quality Pb1-x Lax (Zr0.9Ti0.1)O3 thin films

    NASA Astrophysics Data System (ADS)

    Kumar, Anuj; Pawar, Shuvam; Singh, Kirandeep; Kaur, Davinder

    2018-05-01

    In this study, we have reported the influence of growth temperature on perovskite phase evolution in sputtered deposited high quality Pb1-x Lax (Zr0.9 Ti0.1)O3 (PLZT) thin films on Pt/Ti/SiO2/Si substrate. PLZT thin films were fabricated at substrate temperature ranging from 400 to 700 °C. We have investigated the structural, dielectric, ferroelectric and leakage current characteristics of these thin films. XRD patterns reveal that 600 °C is the optimized temperature to deposit highly (110) oriented perovskite phase PLZT thin film. The further increase in temperature (700 °) causes reappearance of additional peaks corresponding to lead deficient pyrochlore phase. All PLZT thin films show decrease in dielectric constant with frequency. However, PLZT thin film fabricated at 600 °C displays dielectric constant ˜532 at 1 MHz frequency which is relatively higher than other deposited thin films. The P-E loops of these PLZT thin films exhibit strong dependence on deposition temperature. The pure perovskite PZLT thin film shows saturation polarization of ˜51.2µC/cm2 and coercive field (2Ec) ˜67.85 kV/cm. These high quality PLZT thin films finds their applications in non-volatile memory and nano-electro-mechanical systems (NEMS).

  4. A flexoelectric microelectromechanical system on silicon.

    PubMed

    Bhaskar, Umesh Kumar; Banerjee, Nirupam; Abdollahi, Amir; Wang, Zhe; Schlom, Darrell G; Rijnders, Guus; Catalan, Gustau

    2016-03-01

    Flexoelectricity allows a dielectric material to polarize in response to a mechanical bending moment and, conversely, to bend in response to an electric field. Compared with piezoelectricity, flexoelectricity is a weak effect of little practical significance in bulk materials. However, the roles can be reversed at the nanoscale. Here, we demonstrate that flexoelectricity is a viable route to lead-free microelectromechanical and nanoelectromechanical systems. Specifically, we have fabricated a silicon-compatible thin-film cantilever actuator with a single flexoelectrically active layer of strontium titanate with a figure of merit (curvature divided by electric field) of 3.33 MV(-1), comparable to that of state-of-the-art piezoelectric bimorph cantilevers.

  5. Enzyme II/sup Mtl/ of the Escherichia coli phosphoenolpyruvate-dependent phosphotransferase system: identification of the activity-linked cysteine on the mannitol carrier

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pas, H.H.; Robillard, G.T.

    1988-07-26

    The cysteine of the membrane-bound mannitol-specific enzyme II (EII/sup Mtl/) of the Escherichia coli phosphoenolpyruvate-dependent phosphotransferase system have been labeled with 4-vinylpyridine. After proteolytic breakdown and reversed-phase HPLC, the peptides containing cysteines 110, 384, and 571 could be identified. N-Ethylmaleimide (NEM) treatment of the native unphosphorylated enzyme results in incorporation of one NEM label per molecule and loss of enzymatic activity. NEM treatment and inactivation prevented 4-vinylpyridine incorporation into the Cys-384-containing peptide, identifying this residue as the activity-linked cysteine. Both oxidation and phosphorylation of the native enzyme protected the enzyme against NEM labeling of Cys-384. Positive identification of the activity-linkedmore » cysteine was accomplished by inactivation with (/sup 14/C)iodoacetamide, proteolytic fragmentation, isolation of the peptide, and amino acid sequencing.« less

  6. Model documentation: Natural gas transmission and distribution model of the National Energy Modeling System. Volume 1

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    NONE

    1995-02-17

    The Natural Gas Transmission and Distribution Model (NGTDM) is the component of the National Energy Modeling System (NEMS) that is used to represent the domestic natural gas transmission and distribution system. NEMS was developed in the Office of integrated Analysis and Forecasting of the Energy information Administration (EIA). NEMS is the third in a series of computer-based, midterm energy modeling systems used since 1974 by the EIA and its predecessor, the Federal Energy Administration, to analyze domestic energy-economy markets and develop projections. The NGTDM is the model within the NEMS that represents the transmission, distribution, and pricing of natural gas.more » The model also includes representations of the end-use demand for natural gas, the production of domestic natural gas, and the availability of natural gas traded on the international market based on information received from other NEMS models. The NGTDM determines the flow of natural gas in an aggregate, domestic pipeline network, connecting domestic and foreign supply regions with 12 demand regions. The methodology employed allows the analysis of impacts of regional capacity constraints in the interstate natural gas pipeline network and the identification of pipeline capacity expansion requirements. There is an explicit representation of core and noncore markets for natural gas transmission and distribution services, and the key components of pipeline tariffs are represented in a pricing algorithm. Natural gas pricing and flow patterns are derived by obtaining a market equilibrium across the three main elements of the natural gas market: the supply element, the demand element, and the transmission and distribution network that links them. The NGTDM consists of four modules: the Annual Flow Module, the Capacity F-expansion Module, the Pipeline Tariff Module, and the Distributor Tariff Module. A model abstract is provided in Appendix A.« less

  7. Nanoscale mass detection based on vibrating piezoelectric ultrathin films under thermo-electro-mechanical loads

    NASA Astrophysics Data System (ADS)

    Asemi, H. R.; Asemi, S. R.; Farajpour, A.; Mohammadi, M.

    2015-04-01

    The potential applications of piezoelectric nanofilms (PNFs) and double-piezoelectric-nanofilm (DPNF) systems as nanoelectromechanical mass sensors are examined. The PNFs carrying multiple nanoparticles at arbitrary locations are modeled as rectangular nonlocal plates with attached concentrated masses. Using the nonlocal elasticity theory and Hamilton's principle, the differential equations of motion are derived for both PNF-based and DPNF-based nanosensors. The influences of small scale, initial stress and temperature change on the frequency shifts of the nanoelectromechanical sensors are taken into consideration. Explicit expressions are derived for the resonance frequencies of the nanosensors by employing the Galerkin method. The present results show that when the value of nonlocal parameter decreases, the frequency shifts of piezoelectric nanosensors increase. Further, the frequency shifts of DPNF-based mass sensors are always greater than those of PNF-based mass sensors. The present work would be helpful in the design of nanoelectromechanical mass sensors using PNFs.

  8. NASA Administrative Data Base Management Systems, 1984

    NASA Technical Reports Server (NTRS)

    Radosevich, J. D. (Editor)

    1984-01-01

    Strategies for converting to a data base management system (DBMS) and the implementation of the software packages necessary are discussed. Experiences with DBMS at various NASA centers are related including Langley's ADABAS/NATURAL and the NEMS subsystem of the NASA metrology informaton system. The value of the integrated workstation with a personal computer is explored.

  9. Laser-directed 3D assembly of carbon nanotubes using two-photon polymerization (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Liu, Ying; Xiong, Wei; Jiang, Li Jia; Zhou, Yunshen; Li, Dawei; Jiang, Lan; Silvain, Jean-Francois; Lu, Yongfeng

    2017-02-01

    Precise assembly of carbon nanotubes (CNTs) in arbitrary 3D space with proper alignment is critically important and desirable for CNT applications but still remains as a long-standing challenge. Using the two-photon polymerization (TPP) technique, it is possible to fabricate 3D micro/nanoscale CNT/polymer architectures with proper CNT alignments in desired directions, which is expected to enable a broad range of applications of CNTs in functional devices. To unleash the full potential of CNTs, it is strategically important to develop TPP-compatible resins with high CNT concentrations for precise assembly of CNTs into 3D micro/nanostructures for functional device applications. We investigated a thiol grafting method in functionalizing multiwalled carbon nanotubes (MWNTs) to develop TPP-compatible MWNT-thiol-acrylate (MTA) composite resins. The composite resins developed had high MWNT concentrations up to 0.2 wt%, over one order of magnitude higher than previously published work. Significantly enhanced electrical and mechanical properties of the 3D micro/nanostructures were achieved. Precisely controlled MWNT assembly and strong anisotropic effects were confirmed. Microelectronic devices made of the MTA composite polymer were demonstrated. The nanofabrication method can achieve controlled assembly of MWNTs in 3D micro/nanostructures, enabling a broad range of CNT applications, including 3D electronics, integrated photonics, and micro/nanoelectromechanical systems (MEMS/NEMS).

  10. Scaling Effects on Materials Tribology: From Macro to Micro Scale.

    PubMed

    Stoyanov, Pantcho; Chromik, Richard R

    2017-05-18

    The tribological study of materials inherently involves the interaction of surface asperities at the micro to nanoscopic length scales. This is the case for large scale engineering applications with sliding contacts, where the real area of contact is made up of small contacting asperities that make up only a fraction of the apparent area of contact. This is why researchers have sought to create idealized experiments of single asperity contacts in the field of nanotribology. At the same time, small scale engineering structures known as micro- and nano-electromechanical systems (MEMS and NEMS) have been developed, where the apparent area of contact approaches the length scale of the asperities, meaning the real area of contact for these devices may be only a few asperities. This is essentially the field of microtribology, where the contact size and/or forces involved have pushed the nature of the interaction between two surfaces towards the regime where the scale of the interaction approaches that of the natural length scale of the features on the surface. This paper provides a review of microtribology with the purpose to understand how tribological processes are different at the smaller length scales compared to macrotribology. Studies of the interfacial phenomena at the macroscopic length scales (e.g., using in situ tribometry) will be discussed and correlated with new findings and methodologies at the micro-length scale.

  11. Scaling Effects on Materials Tribology: From Macro to Micro Scale

    PubMed Central

    Stoyanov, Pantcho; Chromik, Richard R.

    2017-01-01

    The tribological study of materials inherently involves the interaction of surface asperities at the micro to nanoscopic length scales. This is the case for large scale engineering applications with sliding contacts, where the real area of contact is made up of small contacting asperities that make up only a fraction of the apparent area of contact. This is why researchers have sought to create idealized experiments of single asperity contacts in the field of nanotribology. At the same time, small scale engineering structures known as micro- and nano-electromechanical systems (MEMS and NEMS) have been developed, where the apparent area of contact approaches the length scale of the asperities, meaning the real area of contact for these devices may be only a few asperities. This is essentially the field of microtribology, where the contact size and/or forces involved have pushed the nature of the interaction between two surfaces towards the regime where the scale of the interaction approaches that of the natural length scale of the features on the surface. This paper provides a review of microtribology with the purpose to understand how tribological processes are different at the smaller length scales compared to macrotribology. Studies of the interfacial phenomena at the macroscopic length scales (e.g., using in situ tribometry) will be discussed and correlated with new findings and methodologies at the micro-length scale. PMID:28772909

  12. Is there a shift to "active nanostructures"?

    NASA Astrophysics Data System (ADS)

    Subramanian, Vrishali; Youtie, Jan; Porter, Alan L.; Shapira, Philip

    2010-01-01

    It has been suggested that an important transition in the long-run trajectory of nanotechnology development is a shift from passive to active nanostructures. Such a shift could present different or increased societal impacts and require new approaches for risk assessment. An active nanostructure "changes or evolves its state during its operation," according to the National Science Foundation's (2006) Active Nanostructures and Nanosystems grant solicitation. Active nanostructure examples include nanoelectromechanical systems (NEMS), nanomachines, self-healing materials, targeted drugs and chemicals, energy storage devices, and sensors. This article considers two questions: (a) Is there a "shift" to active nanostructures? (b) How can we characterize the prototypical areas into which active nanostructures may emerge? We build upon the NSF definition of active nanostructures to develop a research publication search strategy, with a particular intent to distinguish between passive and active nanotechnologies. We perform bibliometric analyses and describe the main publication trends from 1995 to 2008. We then describe the prototypes of research that emerge based on reading the abstracts and review papers encountered in our search. Preliminary results suggest that there is a sharp rise in active nanostructures publications in 2006, and this rise is maintained in 2007 and through to early 2008. We present a typology that can be used to describe the kind of active nanostructures that may be commercialized and regulated in the future.

  13. Integrating Unified Gravity Wave Physics into the NOAA Next Generation Global Prediction System

    NASA Astrophysics Data System (ADS)

    Alpert, J. C.; Yudin, V.; Fuller-Rowell, T. J.; Akmaev, R. A.

    2017-12-01

    The Unified Gravity Wave Physics (UGWP) project for the Next Generation Global Prediction System (NGGPS) is a NOAA collaborative effort between the National Centers for Environmental Prediction (NCEP), Environemntal Modeling Center (EMC) and the University of Colorado, Cooperative Institute for Research in Environmental Sciences (CU-CIRES) to support upgrades and improvements of GW dynamics (resolved scales) and physics (sub-grid scales) in the NOAA Environmental Modeling System (NEMS)†. As envisioned the global climate, weather and space weather models of NEMS will substantially improve their predictions and forecasts with the resolution-sensitive (scale-aware) formulations planned under the UGWP framework for both orographic and non-stationary waves. In particular, the planned improvements for the Global Forecast System (GFS) model of NEMS are: calibration of model physics for higher vertical and horizontal resolution and an extended vertical range of simulations, upgrades to GW schemes, including the turbulent heating and eddy mixing due to wave dissipation and breaking, and representation of the internally-generated QBO. The main priority of the UGWP project is unified parameterization of orographic and non-orographic GW effects including momentum deposition in the middle atmosphere and turbulent heating and eddies due to wave dissipation and breaking. The latter effects are not currently represented in NOAA atmosphere models. The team has tested and evaluated four candidate GW solvers integrating the selected GW schemes into the NGGPS model. Our current work and planned activity is to implement the UGWP schemes in the first available GFS/FV3 (open FV3) configuration including adapted GFDL modification for sub-grid orography in GFS. Initial global model results will be shown for the operational and research GFS configuration for spectral and FV3 dynamical cores. †http://www.emc.ncep.noaa.gov/index.php?branch=NEMS

  14. CHAIRMAN'S FOREWORD: First International Symposium on Advanced Nanodevices and Nanotechnology

    NASA Astrophysics Data System (ADS)

    Aoyagi, Yoshinobu; Goodnick, Stephen M.

    2008-03-01

    This volume of Journal of Physics: Conference Series contains selected papers from the First International Symposium on Advanced Nanodevices and Nanotechnology. This conference is a merging of the two previous series New Phenomena in Mesoscopic Structures and the Surfaces and Interfaces of Mesoscopic Devices. This year's conference was held 2-7 December 2007 at the Waikoloa Beach Marriott on the Kohala coast of the big island of Hawaii. The scope of ISANN spans nano-fabrication through complex phase coherent mesoscopic systems including nano-transistors and nano-scale characterization. Topics of interest included: Nano-scale fabrication (high-resolution electron lithography, FIB nano-patterning SFM lithography, SFM stimulated growth, novel patterning, nano-imprint lithography, special etching, and SAMs) Nano-characterization (SFM characterization, BEEM, optical studies of nanostructures, tunneling, properties of discrete impurities, phase coherence, noise, THz studies, electro-luminescence in small structures) Nano-devices (ultra-scaled FETs, quantum SETs, RTDs, ferromagnetic, and spin devices, superlattice arrays, IR detectors with quantum dots and wires, quantum point contacts, non-equilibrium transport, simulation, ballistic transport, molecular electronic devices, carbon nanotubes, spin selection devices, spin-coupled quantum dots, nano-magnetics) Quantum coherent transport (quantum Hall effect, ballistic quantum systems, quantum computing implementations and theory, magnetic spin systems, quantum NEMs) Mesoscopic structures (quantum wires and dots, chaos, non-equilibrium transport, instabilities, nano-electro-mechanical systems, mesoscopic Josephson effects, phase coherence and breaking, Kondo effect) Systems of nano-devices (QCAs, systolic SET processors, quantum neural nets, adaptive effects in circuits, molecular circuits, NEMs) Nanomaterials (nanotubes, nanowires, organic and molecular materials, self-assembled nanowires, organic devices) Nano

  15. Central nervous system toxicity of metallic nanoparticles

    PubMed Central

    Feng, Xiaoli; Chen, Aijie; Zhang, Yanli; Wang, Jianfeng; Shao, Longquan; Wei, Limin

    2015-01-01

    Nanomaterials (NMs) are increasingly used for the therapy, diagnosis, and monitoring of disease- or drug-induced mechanisms in the human biological system. In view of their small size, after certain modifications, NMs have the capacity to bypass or cross the blood–brain barrier. Nanotechnology is particularly advantageous in the field of neurology. Examples may include the utilization of nanoparticle (NP)-based drug carriers to readily cross the blood–brain barrier to treat central nervous system (CNS) diseases, nanoscaffolds for axonal regeneration, nanoelectromechanical systems in neurological operations, and NPs in molecular imaging and CNS imaging. However, NPs can also be potentially hazardous to the CNS in terms of nano-neurotoxicity via several possible mechanisms, such as oxidative stress, autophagy, and lysosome dysfunction, and the activation of certain signaling pathways. In this review, we discuss the dual effect of NMs on the CNS and the mechanisms involved. The limitations of the current research are also discussed. PMID:26170667

  16. Significance of size dependent and material structure coupling on the characteristics and performance of nanocrystalline micro/nano gyroscopes

    NASA Astrophysics Data System (ADS)

    Larkin, K.; Ghommem, M.; Abdelkefi, A.

    2018-05-01

    Capacitive-based sensing microelectromechanical (MEMS) and nanoelectromechanical (NEMS) gyroscopes have significant advantages over conventional gyroscopes, such as low power consumption, batch fabrication, and possible integration with electronic circuits. However, inadequacies in the modeling of these inertial sensors have presented issues of reliability and functionality of micro-/nano-scale gyroscopes. In this work, a micromechanical model is developed to represent the unique microstructure of nanocrystalline materials and simulate the response of micro-/nano-gyroscope comprising an electrostatically-actuated cantilever beam with a tip mass at the free end. Couple stress and surface elasticity theories are integrated into the classical Euler-Bernoulli beam model in order to derive a size-dependent model. This model is then used to investigate the influence of size-dependent effects on the static pull-in instability, the natural frequencies and the performance output of gyroscopes as the scale decreases from micro-to nano-scale. The simulation results show significant changes in the static pull-in voltage and the natural frequency as the scale of the system is decreased. However, the differential frequency between the two vibration modes of the gyroscope is observed to drastically decrease as the size of the gyroscope is reduced. As such, the frequency-based operation mode may not be an efficient strategy for nano-gyroscopes. The results show that a strong coupling between the surface elasticity and material structure takes place when smaller grain sizes and higher void percentages are considered.

  17. Model documentation report: Residential sector demand module of the national energy modeling system

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    NONE

    This report documents the objectives, analytical approach, and development of the National Energy Modeling System (NEMS) Residential Sector Demand Module. The report catalogues and describes the model assumptions, computational methodology, parameter estimation techniques, and FORTRAN source code. This reference document provides a detailed description for energy analysts, other users, and the public. The NEMS Residential Sector Demand Module is currently used for mid-term forecasting purposes and energy policy analysis over the forecast horizon of 1993 through 2020. The model generates forecasts of energy demand for the residential sector by service, fuel, and Census Division. Policy impacts resulting from new technologies,more » market incentives, and regulatory changes can be estimated using the module. 26 refs., 6 figs., 5 tabs.« less

  18. Model documentation renewable fuels module of the National Energy Modeling System

    NASA Astrophysics Data System (ADS)

    1995-06-01

    This report documents the objectives, analytical approach, and design of the National Energy Modeling System (NEMS) Renewable Fuels Module (RFM) as it relates to the production of the 1995 Annual Energy Outlook (AEO95) forecasts. The report catalogs and describes modeling assumptions, computational methodologies, data inputs, and parameter estimation techniques. A number of offline analyses used in lieu of RFM modeling components are also described. The RFM consists of six analytical submodules that represent each of the major renewable energy resources -- wood, municipal solid waste (MSW), solar energy, wind energy, geothermal energy, and alcohol fuels. The RFM also reads in hydroelectric facility capacities and capacity factors from a data file for use by the NEMS Electricity Market Module (EMM). The purpose of the RFM is to define the technological, cost, and resource size characteristics of renewable energy technologies. These characteristics are used to compute a levelized cost to be competed against other similarly derived costs from other energy sources and technologies. The competition of these energy sources over the NEMS time horizon determines the market penetration of these renewable energy technologies. The characteristics include available energy capacity, capital costs, fixed operating costs, variable operating costs, capacity factor, heat rate, construction lead time, and fuel product price.

  19. Model documentation: Renewable Fuels Module of the National Energy Modeling System

    NASA Astrophysics Data System (ADS)

    1994-04-01

    This report documents the objectives, analytical approach, and design of the National Energy Modeling System (NEMS) Renewable Fuels Module (RFM) as it related to the production of the 1994 Annual Energy Outlook (AEO94) forecasts. The report catalogues and describes modeling assumptions, computational methodologies, data inputs, and parameter estimation techniques. A number of offline analyses used in lieu of RFM modeling components are also described. This documentation report serves two purposes. First, it is a reference document for model analysts, model users, and the public interested in the construction and application of the RFM. Second, it meets the legal requirement of the Energy Information Administration (EIA) to provide adequate documentation in support of its models. The RFM consists of six analytical submodules that represent each of the major renewable energy resources -- wood, municipal solid waste (MSW), solar energy, wind energy, geothermal energy, and alcohol fuels. Of these six, four are documented in the following chapters: municipal solid waste, wind, solar and biofuels. Geothermal and wood are not currently working components of NEMS. The purpose of the RFM is to define the technological and cost characteristics of renewable energy technologies, and to pass these characteristics to other NEMS modules for the determination of mid-term forecasted renewable energy demand.

  20. Elasticity, strength, and toughness of single crystal silicon carbide, ultrananocrystalline diamond, and hydrogen-free tetrahedral amorphous carbon

    NASA Astrophysics Data System (ADS)

    Espinosa, H. D.; Peng, B.; Moldovan, N.; Friedmann, T. A.; Xiao, X.; Mancini, D. C.; Auciello, O.; Carlisle, J.; Zorman, C. A.; Merhegany, M.

    2006-08-01

    In this work, the authors report the mechanical properties of three emerging materials in thin film form: single crystal silicon carbide (3C-SiC), ultrananocrystalline diamond, and hydrogen-free tetrahedral amorphous carbon. The materials are being employed in micro- and nanoelectromechanical systems. Several reports addressed some of the mechanical properties of these materials but they are based in different experimental approaches. Here, they use a single testing method, the membrane deflection experiment, to compare these materials' Young's moduli, characteristic strengths, fracture toughnesses, and theoretical strengths. Furthermore, they analyze the applicability of Weibull theory [Proc. Royal Swedish Inst. Eng. Res. 153, 1 (1939); ASME J. Appl. Mech. 18, 293 (1951)] in the prediction of these materials' failure and document the volume- or surface-initiated failure modes by fractographic analysis. The findings are of particular relevance to the selection of micro- and nanoelectromechanical systems materials for various applications of interest.

  1. Mechanical Signature of Heat Generated in a Current-Driven Ferromagnetic Resonance System

    NASA Astrophysics Data System (ADS)

    Cho, Sung Un; Jo, Myunglae; Park, Seondo; Lee, Jae-Hyun; Yang, Chanuk; Kang, Seokwon; Park, Yun Daniel

    2017-07-01

    In a current-driven ferromagnetic resonance (FMR) system, heat generated by time-dependent magnetoresistance effects, caused by magnetization precession, cannot be overlooked. Here, we describe the generated heat by magnetization motion under electric current in a freestanding nanoelectromechanical resonator fashioned from a permalloy (Py )/Pt bilayer. By piezoresistive transduction of Pt, the mechanical mode is electrically detected at room temperature and the internal heat in Py excluding thermoelectric effects is quantified as a shift of the mechanical resonance. We find that the measured spectral shifts correspond to the FMR, which is further verified from the spin-torque FMR measurement. Furthermore, the angular dependence of the mechanical reaction on an applied magnetic field reveals that the full accounting of FMR heat dissipation requires the time-dependent magnetoresistance effect.

  2. The Impacts of Changes to Nevada’s Net Metering Policy on the Financial Performance and Adoption of Distributed Photovoltaics

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gagnon, Pieter; Sigrin, Ben; Gleason, Mike

    Net energy metering (NEM) is a billing mechanism that has historically compensated owners of distributed generation systems at retail rates for any electricity that they export back to the grid rather than consume on-site. NEM can significantly enhance the financial performance of distributed generation systems from the owner’s perspective. The following analysis was designed to illustrate the potential impact of NEM policy and tariff changes implemented in early 2016 in Nevada.

  3. Electromechanical and Chemical Sensing at the Nanoscale: DFT and Transport Modeling

    NASA Astrophysics Data System (ADS)

    Maiti, Amitesh

    Of the many nanoelectronic applications proposed for near to medium-term commercial deployment, sensors based on carbon nanotubes (CNT) and metal-oxide nanowires are receiving significant attention from researchers. Such devices typically operate on the basis of the changes of electrical response characteristics of the active component (CNT or nanowire) when subjected to an externally applied mechanical stress or the adsorption of a chemical or bio-molecule. Practical development of such technologies can greatly benefit from quantum chemical modeling based on density functional theory (DFT), and from electronic transport modeling based on non-equilibrium Green's function (NEGF). DFT can compute useful quantities like possible bond-rearrangements, binding energy, charge transfer, and changes to the electronic structure, while NEGF can predict changes in electronic transport behavior and contact resistance. Effects of surrounding medium and intrinsic structural defects can also be taken into account. In this work we review some recent DFT and transport investigations on (1) CNT-based nano-electromechanical sensors (NEMS) and (2) gas-sensing properties of CNTs and metal-oxide nanowires. We also briefly discuss our current understanding of CNT-metal contacts which, depending upon the metal, the deposition technique, and the masking method can have a significant effect on device performance.

  4. Model documentation report: Commercial Sector Demand Module of the National Energy Modeling System

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    NONE

    1998-01-01

    This report documents the objectives, analytical approach and development of the National Energy Modeling System (NEMS) Commercial Sector Demand Module. The report catalogues and describes the model assumptions, computational methodology, parameter estimation techniques, model source code, and forecast results generated through the synthesis and scenario development based on these components. The NEMS Commercial Sector Demand Module is a simulation tool based upon economic and engineering relationships that models commercial sector energy demands at the nine Census Division level of detail for eleven distinct categories of commercial buildings. Commercial equipment selections are performed for the major fuels of electricity, natural gas,more » and distillate fuel, for the major services of space heating, space cooling, water heating, ventilation, cooking, refrigeration, and lighting. The algorithm also models demand for the minor fuels of residual oil, liquefied petroleum gas, steam coal, motor gasoline, and kerosene, the renewable fuel sources of wood and municipal solid waste, and the minor services of office equipment. Section 2 of this report discusses the purpose of the model, detailing its objectives, primary input and output quantities, and the relationship of the Commercial Module to the other modules of the NEMS system. Section 3 of the report describes the rationale behind the model design, providing insights into further assumptions utilized in the model development process to this point. Section 3 also reviews alternative commercial sector modeling methodologies drawn from existing literature, providing a comparison to the chosen approach. Section 4 details the model structure, using graphics and text to illustrate model flows and key computations.« less

  5. The evolution of energy-transducing systems: Studies with archaebacteria

    NASA Technical Reports Server (NTRS)

    Stan-Lotter, Helga

    1993-01-01

    N-ethylmaleimide (NEM) inhibits the ATPase of H. saccharovorum in a nucleotide protectable manner. The bulk of 14C-NEM is incorporated into subunit 1. Inhibition kinetics indicated a single binding site. To determine the sequence around this site, cyanogen bromide peptides of NEM-labeled ATPase enzyme were prepared and separated on Tris-Tricine gels. Autoradiography indicated that the NEM binding site is probably located in a fragment of Mr 10-12 K. This result will be confirmed by N-terminal sequencing of the peptide. Since the cysteinyl residue, to which NEM is bound, may be located at the C-terminal end, purification and proteolytic treatment of the 10 K peptide will be required. One inhibitor of V-type ATPases, fluoresceinisothiocyanate (FITC) inhibited also the ATPase of H. saccharovorum. Preliminary results indicated protection against inhibition by nucleotides. Localization of the binding sited to the major subunits is in progress. An extraction procedure for the membrane sector of the ATPase complex of H. saccharovorum yielded a preparation which was enriched in a peptide of Mr 5 500. Experiments to test the immunological crossreaction with subunit c from the Escherichia coli F-type ATPase and the labeling with 14C-DCCD are currently carried out. Polyclonal antiserum to the smaller of the major subunits of the ATPase from H. saccharovorum (subunit ll) reacts in Western blots strongly with the alpha and beta subunits of the F1 ATPase of E. coli, suggesting highly conserved regions on both types of ATPases. To elucidate further the regions of homology, cyanogen bromide peptides of the beta subunits were prepared for sequence analysis.

  6. The evolution of energy-transducing systems. Studies with archaebacteria

    NASA Technical Reports Server (NTRS)

    Stan-Lotter, Helga

    1994-01-01

    N-ethylmaleimide (NEM) inhibits the ATPase of H. saccharovorum in a nucleotide protectable manner. The bulk of C-14 NEM is incorporated into subunit one. Cyanogen bromide cleavage of labeled subunit one indicated that NEM bound to a peptide of a Mr of about 8,900. Thus, Cys 262 (H. salinarium numbering) may be the NEM binding site. Cyanogen bromide fragments have been submitted for sequencing. To prove the presence of three Cys residues in subunit one, alkaline cleavage following treatment with NTCB was carried out. Thiol reagents such as p-chloro mercuri phenyl sulfonate also inhibited the ATPase. However, this inhibition was not nucleotide-protectable, suggesting a different location and role for the PCMS-sensitive Cys. The proteolipid which was extracted with chloroform/methanol from the membranes of H. saccharovorum cross-reacted with an antiserum against subunit c (the DCCD-binding protein) of Escherichia coli. Following labeling of membranes from H. saccharovorum with C-14 DCCD under conditions, which inhibited ATP synthesis, the isotope was incorporated into one protein of Mr of about 6,500. Thus, the proteolipid of H. saccharovorum and the DCCD-labeled peptide may be identical. If so, these results suggest that the proteolipid is a component of the membrane sector of an archaeal F-type ATP synthase.

  7. The impact of China's national essential medicine system on improving rational drug use in primary health care facilities: an empirical study in four provinces.

    PubMed

    Song, Yan; Bian, Ying; Petzold, Max; Li, Lingui; Yin, Aitian

    2014-10-25

    The National Essential Medicine System (NEMS) is a new policy in China launched in 2009 to improve the appropriate use of medications. This study aims to examine the outcomes of the NEMS objectives in terms of the rational use of medicines in primary health care facilities in China. A total of 28,651 prescriptions were collected from 146 township health centers in four provinces of China by means of a field survey conducted in 2010-2011. Indicators of rational drug use were extracted and compared using a pre/post design and then evaluated with regard to the World Health Organization (WHO) Standard Guidelines and data from previous research. The average number of drugs per prescription decreased from 3.64 to 3.46 (p < 0.01) between 2009 and 2010. Little effect was found for the NEMS on the average number of antibiotics per prescription, but the percentage of prescriptions including antibiotics decreased from 60.26 to 58.48% (p < 0.01). Prescriptions for injections or adrenal corticosteroids also decreased, to 40.31 and 11.16% of all prescriptions, respectively. All these positive issues were also recorded in 2011. However, each of the above values remained higher than WHO standards. The percentage of drugs prescribed from the Essential Drug List increased after the implementation of the NEMS (p < 0.01). Where the available data allowed changes in costs to be assessed, the average expense per prescription increased significantly, from 25.77 to 27.09 yuan (p < 0.01). The NEMS effectively improved rational medicine use in China. However, polypharmacy and the over-prescription of antibiotics and injections remain common. There is still a large unfinished agenda requiring policy improvements. Treatment guidelines, intensive support supervision, and continuing training for both professionals and consumers are the essential actions that need to be taken.

  8. Model documentation Renewable Fuels Module of the National Energy Modeling System

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    NONE

    1996-01-01

    This report documents the objectives, analaytical approach and design of the National Energy Modeling System (NEMS) Renewable Fuels Module (RFM) as it relates to the production of the 1996 Annual Energy Outlook forecasts. The report catalogues and describes modeling assumptions, computational methodologies, data inputs, and parameter estimation techniques. A number of offline analyses used in lieu of RFM modeling components are also described.

  9. System Control for the Transitional DCS.

    DTIC Science & Technology

    1979-05-01

    Avenue I . NUMBER OF PAGES Reston, VA 22090 300 14. MONITORING AGENCY NAME & ADDRESS(if different from Controlling Office) IS. SECURITY CLASS. (of this...adjusting the routing in the AUTOVON Network. DD FORMj 73 1473 EOITION OF I NOV 65 IS OBSOLETE YV_, UNCLASSIFIED [ L.j 29.? .’ SECURITY CLASSIFICATION OF THIS...PAGE ("en Data Entered) SECURIT’, 1.LASSIPrICATIO04 OP THIS PAGE(Wbmn Deta.Entered) SECURITY CLASIIPICATIOM OF U* PAGE(nem" Data Entoewl I I I SYSTEM

  10. Low mass MEMS/NEMS switch for a substitute of CMOS transistor using single-walled carbon nanotube thin film

    NASA Astrophysics Data System (ADS)

    Jang, Min-Woo

    Power dissipation is a key factor for mobile devices and other low power applications. Complementary metal oxide semiconductor (CMOS) is the dominant integrated circuit (IC) technology responsible for a large part of this power dissipation. As the minimum feature size of CMOS devices enters into the sub 50 nanometer (nm) regime, power dissipation becomes much worse due to intrinsic physical limits. Many approaches have been studied to reduce power dissipation of deeply scaled CMOS ICs. One possible candidate is the electrostatic electromechanical switch, which could be fabricated with conventional CMOS processing techniques. They have critical advantages compared to CMOS devices such as almost zero standby leakage in the off-state due to the absence of a pn junction and a gate oxide, as well as excellent drive current in the on-state due to a metallic channel. Despite their excellent standby power dissipation, the electrostatic MEMS/NEMS switches have not been considered as a viable replacement for CMOS devices due to their large mechanical delay. Moreover, previous literature reveals that their pull-in voltage and switching speed are strongly proportional to each other. This reduces their potential advantage. However, in this work, we theoretically and experimentally demonstrated that the use of single-walled carbon nanotube (SWNT) with very low mass density and strong mechanical properties could provide a route to move off of the conventional trend with respect to the pull-in voltage / switching speed tradeoff observed in the literature. We fabricated 2-terminal fixed- beam switches with aligned composite SWNT thin films. In this work, layer-by-layer (LbL) self-assembly and dielectrophoresis were selected for aligned-composite SWNT thin film deposition. The dense membranes were successfully patterned to form submicron beams by e-beam lithography and oxygen plasma etching. Fixed-fixed beam switches using these membranes successfully operated with approximately 600

  11. Bio-Nanobattery Development and Characterization

    NASA Technical Reports Server (NTRS)

    King, Glen C.; Choi, Sang H.; Chu, Sang-Hyon; Kim, Jae-Woo; Watt, Gerald D.; Lillehei, Peter T.; Park, Yeonjoon; Elliott, James R.

    2005-01-01

    development, and selection of ferritin core materials to allow the broadest range of applications. The potential applications for the distributed power system include autonomously-operating intelligent chips, flexible thin-film electronic circuits, nanoelectromechanical systems (NEMS), ultra-high density data storage devices, nanoelectromagnetics, quantum electronic devices, biochips, nanorobots for medical applications and mechanical nano-fabrication, etc.

  12. Short-term differences in drug prices after implementation of the national essential medicines system: A case study in rural Jiangxi Province, China.

    PubMed

    Wang, Junyong; Liu, Xia; Wang, Suzhen; Chen, Heli; Wang, Xun; Zhou, Wei; Wang, Li; Zhu, Yanchen; Zheng, Xianping; Hao, Mo

    2015-01-01

    China's 2009 national essential medicine system (NEMS) was designed to reduce prices through a zero-markup policy and a centralized bidding system. To analyze NEMS's short-term impact on drug prices, we estimated the retail and wholesale prices before and after the reform at health institutions in rural Jiangxi Province. We undertook two cross-sectional surveys of prices of 39 medicines in November 2008 and May 2010, calculated inflation adjusted prices, and used the Wilcoxon signed-rank and rank-sum tests to examine price changes at different health institutions. Retail prices at pilot (P < 0.01) and nonpilot (P < 0.01) township health centers decreased significantly, whereas the declines at retail pharmacies (P = 0.57) and village clinics (P = 0.29) were insignificant. The decline at pilot township health centers was the largest, compared with other kinds of health institutions (P < 0.01). Retail prices of essential and non-essential medicines declined significantly at pilot facilities (P < 0.05); price drops for non-essential medicines occurred only at pilot facilities (P < 0.05). No significant decline of wholesale prices were found at pilot (P = 0.86) and nonpilot units (P = 0.18), retail pharmacies (P = 0.18), and village clinics (P = 0.20). The wholesale prices changes at pilot units before and after the reform were higher than at nonpilot public units (P < 0.05), retail pharmacies (P < 0.05), and village clinics (P < 0.05). While the NEMS zero-markup policy significantly reduced retail prices at pilot health institutions, the centralized bidding system was insufficient to lower wholesale prices. A drug price management system should be constructed to control medicine prices and a long-term price information system is needed to monitor price changes.

  13. Bio-inspired scale-like surface textures and their tribological properties.

    PubMed

    Greiner, Christian; Schäfer, Michael

    2015-06-30

    Friction, wear and the associated energy dissipation are major challenges in all systems containing moving parts. Examples range from nanoelectromechanical systems over hip prosthesis to off-shore wind turbines. Bionic approaches have proven to be very successful in many engineering problems, while investigating the potential of a bio-inspired approach in creating morphological surface textures is a relatively new field of research. Here, we developed laser-created textures inspired by the scales found on the skin of snakes and certain lizards. We show that this bio-inspired surface morphology reduced dry sliding friction forces by more than 40%. In lubricated contacts the same morphology increased friction by a factor of three. Two different kinds of morphologies, one with completely overlapping scales and one with the scales arranged in individual rows, were chosen. In lubricated as well as unlubricated contacts, the surface texture with the scales in rows showed lower friction forces than the completely overlapping ones. We anticipate that these results could have significant impact in all dry sliding contacts, ranging from nanoelectromechanical and micro-positioning systems up to large-scale tribological contacts which cannot be lubricated, e.g. because they are employed in a vacuum environment.

  14. Imidazolium-based ionic liquids used as additives in the nanolubrication of silicon surfaces.

    PubMed

    Amorim, Patrícia M; Ferraria, Ana M; Colaço, Rogério; Branco, Luís C; Saramago, Benilde

    2017-01-01

    In recent years, with the development of micro/nanoelectromechanical systems (MEMS/NEMS), the demand for efficient lubricants of silicon surfaces intensified. Although the use of ionic liquids (ILs) as additives to base oils in the lubrication of steel/steel or other types of metal/ metal tribological pairs has been investigated, the number of studies involving Si is very low. In this work, we tested imidazolium-based ILs as additives to the base oil polyethylene glycol (PEG) to lubricate Si surfaces. The friction coefficients were measured in a nanotribometer. The viscosity of the PEG + IL mixtures as well as their contact angles on the Si surface were measured. The topography and chemical composition of the substrates surfaces were determined with atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), respectively. Due to the hygroscopic properties of PEG, the first step was to assess the effect of the presence of water. Then, a series of ILs based on the cations 1-ethyl-3-methylimidazolium [EMIM], 1-butyl-3-methylimidazolium [BMIM], 1-ethyl-3-vinylimidazolium [EVIM], 1-(2-hydroxyethyl)-3-methylimidazolium [C 2 OHMIM] and 1-allyl-3-methylimidazolium [AMIM] combined with the anions dicyanamide [DCA], trifluoromethanesulfonate [TfO], and ethylsulfate [EtSO 4 ] were added to dry PEG. All additives (2 wt %) led to a decrease in friction coefficient as well as an increase in viscosity (with the exception of [AMIM][TfO]) and improved the Si wettability. The additives based on the anion [EtSO 4 ] exhibited the most promising tribological behavior, which was attributed to the strong interaction with the Si surface ensuring the formation of a stable surface layer, which hinders the contact between the sliding surfaces.

  15. Evaluation, in three provinces, of the introduction and impact of China's National Essential Medicines Scheme.

    PubMed

    Li, Yang; Ying, Cui; Sufang, Guo; Brant, Philippa; Bin, Li; Hipgrave, David

    2013-03-01

    To evaluate implementation of the National Essential Medicines Scheme (NEMS) in rural China. Two rural counties/districts in each of three provinces where NEMS had been implemented were surveyed. Information was collected from NEMS staff at the province, county/district, township and village levels; patients with chronic disease were also interviewed. Service provision, finances, prescriptions, inpatient records and the expenditures of patients with certain diagnoses were investigated in township hospitals and village clinics. The results were compared with the corresponding data recorded before NEMS was introduced. Following the introduction of NEMS, drug procurement in each study location was systematized. Total drug costs declined. This, and improved prescribing, reduced the costs of outpatient and inpatient care and led, apparently, to increased uptake of health services. However, the prices of some drugs had increased and the availability of others had declined. The compensation of health-care providers for NEMS-related reductions in their incomes had been largely ineffective. As a result of the introduction of NEMS, health facilities relied more on public financing. Many health-care providers complained about higher workloads and lower incomes. Although it was well conceived, the introduction of NEMS into China's decentralized, fee-for-service system of health care has not been straightforward. It has highlighted the problems associated with attempts to modernize health care and health financing for patients' benefit. Sustainable mechanisms to compensate health-care providers for lost income are needed to ensure that NEMS is a success.

  16. Fabrication of Single, Vertically Aligned Carbon Nanotubes in 3D Nanoscale Architectures

    NASA Technical Reports Server (NTRS)

    Kaul, Anupama B.; Megerian, Krikor G.; Von Allmen, Paul A.; Baron, Richard L.

    2010-01-01

    Plasma-enhanced chemical vapor deposition (PECVD) and high-throughput manufacturing techniques for integrating single, aligned carbon nanotubes (CNTs) into novel 3D nanoscale architectures have been developed. First, the PECVD growth technique ensures excellent alignment of the tubes, since the tubes align in the direction of the electric field in the plasma as they are growing. Second, the tubes generated with this technique are all metallic, so their chirality is predetermined, which is important for electronic applications. Third, a wafer-scale manufacturing process was developed that is high-throughput and low-cost, and yet enables the integration of just single, aligned tubes with nanoscale 3D architectures with unprecedented placement accuracy and does not rely on e-beam lithography. Such techniques should lend themselves to the integration of PECVD grown tubes for applications ranging from interconnects, nanoelectromechanical systems (NEMS), sensors, bioprobes, or other 3D electronic devices. Chemically amplified polyhydroxystyrene-resin-based deep UV resists were used in conjunction with excimer laser-based (lambda = 248 nm) step-and-repeat lithography to form Ni catalyst dots = 300 nm in diameter that nucleated single, vertically aligned tubes with high yield using dc PECVD growth. This is the first time such chemically amplified resists have been used, resulting in the nucleation of single, vertically aligned tubes. In addition, novel 3D nanoscale architectures have been created using topdown techniques that integrate single, vertically aligned tubes. These were enabled by implementing techniques that use deep-UV chemically amplified resists for small-feature-size resolution; optical lithography units that allow unprecedented control over layer-to-layer registration; and ICP (inductively coupled plasma) etching techniques that result in near-vertical, high-aspect-ratio, 3D nanoscale architectures, in conjunction with the use of materials that are

  17. Investigation of Procedures for Automatic Resonance Extraction from Noisy Transient Electromagnetics Data. Volume III. Translation of Prony’s Original Paper and Bibliography of Prony’s Method

    DTIC Science & Technology

    1981-08-17

    Van Blaricum, "On the Source of Parameter Bias in Prony’s Method," 1980 NEM Conference, Disneyland Hotel, August 1980. Auton, J.R., "An Unbiased...Method for the Estimation of the SEM Parameters of an Electromagnetic System," 1980 NEM Conference, Disneyland Hotel, August 1980. Auton, J.R. and M.L...34 1980 NEM Conference, Disneyland Hotel, August 5-7, 1980. Chuang, C.W. and D.L. Moffatt, "Complex Natural Responances of Radar Targets via Prony’s

  18. SMART Power Systems for ANTS Missions

    NASA Astrophysics Data System (ADS)

    Clark, P. E.; Floyd, S. R.; Curtis, S. A.; Rilee, M. L.

    2005-02-01

    Autonomous NanoTechnology Swarm (ANTS) Architecture is based on Addressable Reconfigurable Technology (ART) adaptable for the full spectrum of activities in space. ART systems based on currently available electromechanical (EMS) technology could support human crews on the lunar surface within the next 10 to 15 years. Two or more decades from now, NEMS (Super Miniaturized ART or SMART) technology could perform fully autonomous surveys and operations beyond the reach of human crews. Power system requirements would range from 1 kg to generate tens of Watts for near term ART applications, such as a lunar or Mars Lander Amorphous Rover Antenna (LARA), to <0.1 kg to generate hundreds of mWatts for more advanced SMART applications.

  19. 48 CFR 1852.245-74 - Contractor accountable on-site Government property.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Management System (NEMS)) of all equipment costing $1000 and over, plus that equipment designated as...-through utilization inspections; (8) Screen NEMS before acquiring any equipment costing $1000 or over, plus equipment designated by the installation as sensitive and costing $500 and over; (9) Support the...

  20. Evaluation, in three provinces, of the introduction and impact of China’s National Essential Medicines Scheme

    PubMed Central

    Li, Yang; Sufang, Guo; Brant, Philippa; Bin, Li; Hipgrave, David

    2013-01-01

    Abstract Objective To evaluate implementation of the National Essential Medicines Scheme (NEMS) in rural China. Methods Two rural counties/districts in each of three provinces where NEMS had been implemented were surveyed. Information was collected from NEMS staff at the province, county/district, township and village levels; patients with chronic disease were also interviewed. Service provision, finances, prescriptions, inpatient records and the expenditures of patients with certain diagnoses were investigated in township hospitals and village clinics. The results were compared with the corresponding data recorded before NEMS was introduced. Findings Following the introduction of NEMS, drug procurement in each study location was systematized. Total drug costs declined. This, and improved prescribing, reduced the costs of outpatient and inpatient care and led, apparently, to increased uptake of health services. However, the prices of some drugs had increased and the availability of others had declined. The compensation of health-care providers for NEMS-related reductions in their incomes had been largely ineffective. As a result of the introduction of NEMS, health facilities relied more on public financing. Many health-care providers complained about higher workloads and lower incomes. Conclusion Although it was well conceived, the introduction of NEMS into China’s decentralized, fee-for-service system of health care has not been straightforward. It has highlighted the problems associated with attempts to modernize health care and health financing for patients’ benefit. Sustainable mechanisms to compensate health-care providers for lost income are needed to ensure that NEMS is a success. PMID:23476091

  1. Transportation Sector Model of the National Energy Modeling System. Volume 1

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    NONE

    1998-01-01

    This report documents the objectives, analytical approach and development of the National Energy Modeling System (NEMS) Transportation Model (TRAN). The report catalogues and describes the model assumptions, computational methodology, parameter estimation techniques, model source code, and forecast results generated by the model. The NEMS Transportation Model comprises a series of semi-independent models which address different aspects of the transportation sector. The primary purpose of this model is to provide mid-term forecasts of transportation energy demand by fuel type including, but not limited to, motor gasoline, distillate, jet fuel, and alternative fuels (such as CNG) not commonly associated with transportation. Themore » current NEMS forecast horizon extends to the year 2010 and uses 1990 as the base year. Forecasts are generated through the separate consideration of energy consumption within the various modes of transport, including: private and fleet light-duty vehicles; aircraft; marine, rail, and truck freight; and various modes with minor overall impacts, such as mass transit and recreational boating. This approach is useful in assessing the impacts of policy initiatives, legislative mandates which affect individual modes of travel, and technological developments. The model also provides forecasts of selected intermediate values which are generated in order to determine energy consumption. These elements include estimates of passenger travel demand by automobile, air, or mass transit; estimates of the efficiency with which that demand is met; projections of vehicle stocks and the penetration of new technologies; and estimates of the demand for freight transport which are linked to forecasts of industrial output. Following the estimation of energy demand, TRAN produces forecasts of vehicular emissions of the following pollutants by source: oxides of sulfur, oxides of nitrogen, total carbon, carbon dioxide, carbon monoxide, and volatile organic

  2. Validation of "nine equivalents of nursing manpower use score" on an independent data sample.

    PubMed

    Rothen, H U; Küng, V; Ryser, D H; Zürcher, R; Regli, B

    1999-06-01

    To compare the recently developed "nine equivalents of nursing manpower use score" (NEMS) with the simplified Therapeutic Intervention Scoring System (TISS-28). Prospective single centre study. Adult 30-bed medical-surgical intensive care unit (ICU) in a tertiary care university hospital. Data from all patients admitted in 1997 to the ICU were included in the study. NEMS and TISS-28 items were recorded prospectively for each nursing shift. There were three shifts per day. The Simplified Acute Physiology Score (SAPS) II was calculated for the first 24 h of ICU stay and each patient's basic demographic data were collected. The agreement between NEMS and TISS-28 was assessed by calculating the mean difference and the standard deviation of the differences between the two measures. Further, regression techniques and Pearson's correlation were used. Altogether, 2743 patients with a total of 28,220 nursing shifts were included; 62% of the shifts were used for postoperative/trauma patients and 38% for medical patients. Mean NEMS was 26.0 +/- 8.1 and mean TISS-28 was 26.5 +/- 7.9. The scores differed by < or = 3 points in 49 % of all shifts. The bias was -0.5 +/- 5.3 (95% confidence interval -0.47 to -0.60) and the limits of agreement were -11.1 to +10.1. The relation between the two systems was NEMS = 4.7 +/- 0.8 x TISS-28 (r = 0.78, r2 = 0.62, p < 0.001). Including postoperative/trauma patients only: NEMS = 1.9 +/- 0.9 x TISS-28, for medical patients this equation was: NEMS = 6.0 + 0.8 x TISS-28. First-day SAPS II explained 11% of the variability in first-shift NEMS and 5% of the variability in first-shift TISS-28. This study confirms a good agreement between TISS-28 and NEMS in a large, independent sample. However, as shown by the differences between medical and postoperative/trauma patients, a change in case mix may result in different regression equations. Further, wide limits of agreement indicate that there may be a rather large variability between the two measures

  3. Imidazolium-based ionic liquids used as additives in the nanolubrication of silicon surfaces

    PubMed Central

    Amorim, Patrícia M; Ferraria, Ana M; Colaço, Rogério; Branco, Luís C

    2017-01-01

    In recent years, with the development of micro/nanoelectromechanical systems (MEMS/NEMS), the demand for efficient lubricants of silicon surfaces intensified. Although the use of ionic liquids (ILs) as additives to base oils in the lubrication of steel/steel or other types of metal/ metal tribological pairs has been investigated, the number of studies involving Si is very low. In this work, we tested imidazolium-based ILs as additives to the base oil polyethylene glycol (PEG) to lubricate Si surfaces. The friction coefficients were measured in a nanotribometer. The viscosity of the PEG + IL mixtures as well as their contact angles on the Si surface were measured. The topography and chemical composition of the substrates surfaces were determined with atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), respectively. Due to the hygroscopic properties of PEG, the first step was to assess the effect of the presence of water. Then, a series of ILs based on the cations 1-ethyl-3-methylimidazolium [EMIM], 1-butyl-3-methylimidazolium [BMIM], 1-ethyl-3-vinylimidazolium [EVIM], 1-(2-hydroxyethyl)-3-methylimidazolium [C2OHMIM] and 1-allyl-3-methylimidazolium [AMIM] combined with the anions dicyanamide [DCA], trifluoromethanesulfonate [TfO], and ethylsulfate [EtSO4] were added to dry PEG. All additives (2 wt %) led to a decrease in friction coefficient as well as an increase in viscosity (with the exception of [AMIM][TfO]) and improved the Si wettability. The additives based on the anion [EtSO4] exhibited the most promising tribological behavior, which was attributed to the strong interaction with the Si surface ensuring the formation of a stable surface layer, which hinders the contact between the sliding surfaces. PMID:29046844

  4. Next Generation Community Based Unified Global Modeling System Development and Operational Implementation Strategies at NCEP

    NASA Astrophysics Data System (ADS)

    Tallapragada, V.

    2017-12-01

    NOAA's Next Generation Global Prediction System (NGGPS) has provided the unique opportunity to develop and implement a non-hydrostatic global model based on Geophysical Fluid Dynamics Laboratory (GFDL) Finite Volume Cubed Sphere (FV3) Dynamic Core at National Centers for Environmental Prediction (NCEP), making a leap-step advancement in seamless prediction capabilities across all spatial and temporal scales. Model development efforts are centralized with unified model development in the NOAA Environmental Modeling System (NEMS) infrastructure based on Earth System Modeling Framework (ESMF). A more sophisticated coupling among various earth system components is being enabled within NEMS following National Unified Operational Prediction Capability (NUOPC) standards. The eventual goal of unifying global and regional models will enable operational global models operating at convective resolving scales. Apart from the advanced non-hydrostatic dynamic core and coupling to various earth system components, advanced physics and data assimilation techniques are essential for improved forecast skill. NGGPS is spearheading ambitious physics and data assimilation strategies, concentrating on creation of a Common Community Physics Package (CCPP) and Joint Effort for Data Assimilation Integration (JEDI). Both initiatives are expected to be community developed, with emphasis on research transitioning to operations (R2O). The unified modeling system is being built to support the needs of both operations and research. Different layers of community partners are also established with specific roles/responsibilities for researchers, core development partners, trusted super-users, and operations. Stakeholders are engaged at all stages to help drive the direction of development, resources allocations and prioritization. This talk presents the current and future plans of unified model development at NCEP for weather, sub-seasonal, and seasonal climate prediction applications with special

  5. Systematic investigations on fused π-system compounds of seven benzene rings prepared by photocyclization of diphenanthrylethenes.

    PubMed

    Fujino, Shota; Yamaji, Minoru; Okamoto, Hideki; Mutai, Toshiki; Yoshikawa, Isao; Houjou, Hirohiko; Tani, Fumito

    2017-06-14

    We studied the photoproducts of 1-(n-phenanthryl)-2-(m-phenanthryl)ethenes (nEm; n, m = 1, 3 and 9) for understanding photocyclization patterns based on NMR spectroscopy. The crystal structures of the photoproducts were analyzed by X-ray crystallography, and the photophysical features of the photocyclized molecules were investigated based on emission and transient absorption measurements. Phenanthrene derivatives substituted at the 1- and 3-positions were prepared for synthesizing nEm by photocyclization of stilbene derivatives. We obtained four types of primary photoproducts (n@m) from the corresponding nEm. Two of them were found to have racemic molecular structures in the single crystal determined by X-ray crystallography. Besides the primary photoproducts, two types of secondary photoproducts (n@mPP) were isolated. Fluorescence quantum yields and lifetimes of the obtained photoproducts were determined in solution whereas the definite fluorescence quantum yields were obtained in the powder. Observation of the triplet-triplet absorption spectra in solution by laser photolysis techniques showed that intersystem crossing to the triplet state competes with the fluorescence process.

  6. Physics at the FMQT’08 conference

    NASA Astrophysics Data System (ADS)

    Špička, V.; Nieuwenhuizen, Th. M.; Keefe, P. D.

    2010-01-01

    This paper summarizes the recent state of the art of the following topics presented at the FQMT’08 conference: Foundations of quantum physics, Quantum measurement; Quantum noise, decoherence and dephasing; Cold atoms and Bose-Einstein condensation; Physics of quantum computing and information; Nonequilibrium quantum statistical mechanics; Quantum, mesoscopic and partly classical thermodynamics; Mesoscopic, nano-electro-mechanical systems and optomechanical systems; Spins systems and their dynamics, Brownian motion and molecular motors; Physics of biological systems, and Relevant experiments from the nanoscale to the macroscale. To all these subjects an introduction is given and the recent literature is overviewed. The paper contains some 680 references in total.

  7. Ames Culture Chamber System: Enabling Model Organism Research Aboard the international Space Station

    NASA Technical Reports Server (NTRS)

    Steele, Marianne

    2014-01-01

    Understanding the genetic, physiological, and behavioral effects of spaceflight on living organisms and elucidating the molecular mechanisms that underlie these effects are high priorities for NASA. Certain organisms, known as model organisms, are widely studied to help researchers better understand how all biological systems function. Small model organisms such as nem-atodes, slime mold, bacteria, green algae, yeast, and moss can be used to study the effects of micro- and reduced gravity at both the cellular and systems level over multiple generations. Many model organisms have sequenced genomes and published data sets on their transcriptomes and proteomes that enable scientific investigations of the molecular mechanisms underlying the adaptations of these organisms to space flight.

  8. Subnanometer Motion of Cargoes Driven by Thermal Gradients Along Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Barreiro, Amelia; Rurali, Riccardo; Hernández, Eduardo R.; Moser, Joel; Pichler, Thomas; Forró, László; Bachtold, Adrian

    2008-05-01

    An important issue in nanoelectromechanical systems is developing small electrically driven motors. We report on an artificial nanofabricated motor in which one short carbon nanotube moves relative to another coaxial nanotube. A cargo is attached to an ablated outer wall of a multiwalled carbon nanotube that can rotate and/or translate along the inner nanotube. The motion is actuated by imposing a thermal gradient along the nanotube, which allows for subnanometer displacements, as opposed to an electromigration or random walk effect.

  9. Effect of diagnosis and treatment of clinical endometritis based on vaginal discharge score grading system in postpartum Holstein cows

    PubMed Central

    OKAWA, Hiroaki; FUJIKURA, Atsushi; WIJAYAGUNAWARDANE, Missaka M.P.; VOS, Peter L.A.M.; TANIGUCHI, Masayasu; TAKAGI, Mitsuhiro

    2017-01-01

    In this study, the prevalence, effectiveness of diagnosis, and treatment based on vaginal discharge score (VDS) of clinical endometritis in cattle were evaluated. To detect clinical endometritis and classify its severity, vaginoscopy was performed during 21 to 60 days postpartum in 164 Holstein cows consisting of 229 lactations. Groups were defined using the 4-point VDS scale. Study groups included the following: non-endometritis (VDS=0; no/clear mucus; NEM group; n=168); mild endometritis, no treatment (VDS=1; mucus containing flecks of white/off-white pus; NTR group; n=30); and severe endometritis, treated with PGF2α (VDS≥2; discharge containing <50% pus; and VDS=3; discharge containing >50% pus, and fluid or uterine horn asymmetry; TEM group; n=31). Cows treated with PGF2α that did not recover (VDS≥1, n=5) received intrauterine procaine penicillin and streptomycin. Prevalence of clinical endometritis (VDS≥1) was 26.6%. The NTR group required significantly more artificial inseminations per pregnancy than NEM and TEM groups (2.8 ± 1.8 vs 2.0 ± 1.3, 1.9 ± 0.8, P<0.05). In survival analysis, the proportion of non-pregnant cows was higher in the NTR group compared to the NEM (P=0.012) and TEM (P=0.076) groups. In the TEM group, calving to first artificial insemination interval tended to be higher in cows treated 41 to 60 days postpartum than cows treated 29 to 40 days postpartum (97.2 ± 27.1 vs 74.4 ± 19.7, P=0.084). Our study suggests that cows with VDS=1 may require treatment to recover fertility. Diagnosis and treatment of clinical endometritis based on a VDS grading system may improve dairy herd reproductive performance. PMID:28740032

  10. Effect of diagnosis and treatment of clinical endometritis based on vaginal discharge score grading system in postpartum Holstein cows.

    PubMed

    Okawa, Hiroaki; Fujikura, Atsushi; Wijayagunawardane, Missaka M P; Vos, Peter L A M; Taniguchi, Masayasu; Takagi, Mitsuhiro

    2017-09-12

    In this study, the prevalence, effectiveness of diagnosis, and treatment based on vaginal discharge score (VDS) of clinical endometritis in cattle were evaluated. To detect clinical endometritis and classify its severity, vaginoscopy was performed during 21 to 60 days postpartum in 164 Holstein cows consisting of 229 lactations. Groups were defined using the 4-point VDS scale. Study groups included the following: non-endometritis (VDS=0; no/clear mucus; NEM group; n=168); mild endometritis, no treatment (VDS=1; mucus containing flecks of white/off-white pus; NTR group; n=30); and severe endometritis, treated with PGF2α (VDS≥2; discharge containing <50% pus; and VDS=3; discharge containing >50% pus, and fluid or uterine horn asymmetry; TEM group; n=31). Cows treated with PGF2α that did not recover (VDS≥1, n=5) received intrauterine procaine penicillin and streptomycin. Prevalence of clinical endometritis (VDS≥1) was 26.6%. The NTR group required significantly more artificial inseminations per pregnancy than NEM and TEM groups (2.8 ± 1.8 vs 2.0 ± 1.3, 1.9 ± 0.8, P<0.05). In survival analysis, the proportion of non-pregnant cows was higher in the NTR group compared to the NEM (P=0.012) and TEM (P=0.076) groups. In the TEM group, calving to first artificial insemination interval tended to be higher in cows treated 41 to 60 days postpartum than cows treated 29 to 40 days postpartum (97.2 ± 27.1 vs 74.4 ± 19.7, P=0.084). Our study suggests that cows with VDS=1 may require treatment to recover fertility. Diagnosis and treatment of clinical endometritis based on a VDS grading system may improve dairy herd reproductive performance.

  11. Biomimetic patterned surfaces for controllable friction in micro- and nanoscale devices

    NASA Astrophysics Data System (ADS)

    Singh, Arvind; Suh, Kahp-Yang

    2013-12-01

    Biomimetics is the study and simulation of biological systems for desired functional properties. It involves the transformation of underlying principles discovered in nature into man-made technologies. In this context, natural surfaces have significantly inspired and motivated new solutions for micro- and nano-scale devices (e.g., Micro/Nano-Electro-Mechanical Systems, MEMS/NEMS) towards controllable friction, during their operation. As a generic solution to reduce friction at small scale, various thin films/coatings have been employed in the last few decades. In recent years, inspiration from `Lotus Effect' has initiated a new research direction for controllable friction with biomimetic patterned surfaces. By exploiting the intrinsic hydrophobicity and ability to reduce contact area, such micro- or nano-patterned surfaces have demonstrated great strength and potential for applications in MEMS/NEMS devices. This review highlights recent advancements on the design, development and performance of these biomimetic patterned surfaces. Also, we present some hybrid approaches to tackle current challenges in biomimetic tribological applications for MEMS/NEMS devices.

  12. Designing a Double-Pole Nanoscale Relay Based on a Carbon Nanotube: A Theoretical Study

    NASA Astrophysics Data System (ADS)

    Mu, Weihua; Ou-Yang, Zhong-can; Dresselhaus, Mildred S.

    2017-08-01

    We theoretically investigate a novel and powerful double-pole nanoscale relay based on a carbon nanotube, which is one of the nanoelectromechanical switches being able to work under the strong nuclear radiation, and analyze the physical mechanism of the operating stages in the operation, including "pull in," "connection," and "pull back," as well as the key factors influencing the efficiency of the devices. We explicitly provide the analytical expression of the two important operation voltages, Vpull in and Vpull back , therefore clearly showing the dependence of the material properties and geometry of the present devices by the analytical method from basic physics, avoiding complex numerical calculations. Our method is easy to use in preparing the design guide for fabricating the present device and other nanoelectromechanical devices.

  13. Bit storage and bit flip operations in an electromechanical oscillator.

    PubMed

    Mahboob, I; Yamaguchi, H

    2008-05-01

    The Parametron was first proposed as a logic-processing system almost 50 years ago. In this approach the two stable phases of an excited harmonic oscillator provide the basis for logic operations. Computer architectures based on LC oscillators were developed for this approach, but high power consumption and difficulties with integration meant that the Parametron was rendered obsolete by the transistor. Here we propose an approach to mechanical logic based on nanoelectromechanical systems that is a variation on the Parametron architecture and, as a first step towards a possible nanomechanical computer, we demonstrate both bit storage and bit flip operations.

  14. Methodology for the Assessment of the Macroeconomic Impacts of Stricter CAFE Standards - Addendum

    EIA Publications

    2002-01-01

    This assessment of the economic impacts of Corporate Average Fuel Economy (CAFÉ) standards marks the first time the Energy Information Administration has used the new direct linkage of the DRI-WEFA Macroeconomic Model to the National Energy Modeling System (NEMS) in a policy setting. This methodology assures an internally consistent solution between the energy market concepts forecast by NEMS and the aggregate economy as forecast by the DRI-WEFA Macroeconomic Model of the U.S. Economy.

  15. Passive potassium transport in LK sheep red cells. Modification by N- ethyl maleimide

    PubMed Central

    1983-01-01

    Passive K transport, as modified by N-ethyl maleimide (NEM), was studied in erythrocytes of the low-K (LK) phenotype of sheep. Brief (5- min) treatment with NEM at less than 0.5 mM caused inhibition of passive K influx; NEM at concentrations greater than 0.5 mM caused stimulation of K influx. NEM had similar effects on K efflux. The treatments with NEM did not affect cell volumes (passive K transport in LK cells is sensitive to changes in cell volume). The stimulation of K transport by high [NEM] was also not a consequence of an effect on the metabolic state of the cells. Passive K transport in LK cells is dependent on Cl (it is inhibited in Cl-free media; it may be K/Cl cotransport). NEM had no effect on K influx in Cl-free (NO3- substituted) media. Pretreatment of the cells with anti-L antiserum (L antigen is found on LK cells and not on HK cells) prevented stimulation of K influx by NEM, but did not prevent inhibition. Therefore, NEM modifies the Cl-dependent K transport pathway at two separate sites, a low-affinity site, at which it stimulates, and a high-affinity site, at which it inhibits. Anti-L antibody prevents NEM's action, but only at the low-affinity site. PMID:6875508

  16. Analyzing gene perturbation screens with nested effects models in R and bioconductor.

    PubMed

    Fröhlich, Holger; Beissbarth, Tim; Tresch, Achim; Kostka, Dennis; Jacob, Juby; Spang, Rainer; Markowetz, F

    2008-11-01

    Nested effects models (NEMs) are a class of probabilistic models introduced to analyze the effects of gene perturbation screens visible in high-dimensional phenotypes like microarrays or cell morphology. NEMs reverse engineer upstream/downstream relations of cellular signaling cascades. NEMs take as input a set of candidate pathway genes and phenotypic profiles of perturbing these genes. NEMs return a pathway structure explaining the observed perturbation effects. Here, we describe the package nem, an open-source software to efficiently infer NEMs from data. Our software implements several search algorithms for model fitting and is applicable to a wide range of different data types and representations. The methods we present summarize the current state-of-the-art in NEMs. Our software is written in the R language and freely avail-able via the Bioconductor project at http://www.bioconductor.org.

  17. Frequency stabilization in nonlinear MEMS and NEMS oscillators

    DOEpatents

    Lopez, Omar Daniel; Antonio, Dario

    2014-09-16

    An illustrative system includes an amplifier operably connected to a phase shifter. The amplifier is configured to amplify a voltage from an oscillator. The phase shifter is operably connected to a driving amplitude control, wherein the phase shifter is configured to phase shift the amplified voltage and is configured to set an amplitude of the phase shifted voltage. The oscillator is operably connected to the driving amplitude control. The phase shifted voltage drives the oscillator. The oscillator is at an internal resonance condition, based at least on the amplitude of the phase shifted voltage, that stabilizes frequency oscillations in the oscillator.

  18. Physics at the FQMT'11 conference

    NASA Astrophysics Data System (ADS)

    Špička, V.; Nieuwenhuizen, Th M.; Keefe, P. D.

    2012-11-01

    This paper deals with the recent state of the art of the following topics presented at the FQMT'11 conference: foundations of quantum physics, quantum measurement; nonequilibrium quantum statistical physics; quantum thermodynamics; quantum measurement, entanglement and coherence; dissipation, dephasing, noise, and decoherence; quantum optics; macroscopic quantum behavior; e.g. cold atoms; Bose-Einstein condensates; physics of quantum computing and quantum information; mesoscopic, nano-electro-mechanical systems and nano-optical systems; spin systems and their dynamics; biological systems and molecular motors; and cosmology, gravitation and astrophysics. The lectures and discussions at the FQMT'11 conference, as well as the contributions to the related topical issue, reveal important themes for future development. The recent literature is included.

  19. Tuning all-Optical Analog to Electromagnetically Induced Transparency in nanobeam cavities using nanoelectromechanical system.

    PubMed

    Shi, Peng; Zhou, Guangya; Deng, Jie; Tian, Feng; Chau, Fook Siong

    2015-09-29

    We report the observations of all-optical electromagnetically induced transparency in nanostructures using waveguide side-coupled with photonic crystal nanobeam cavities, which has measured linewidths much narrower than individual resonances. The quality factor of transparency resonance can be 30 times larger than those of measured individual resonances. When the gap between cavity and waveguide is reduced to 10 nm, the bandwidth of destructive interference region can reach 10 nm while the width of transparency resonance is 0.3 nm. Subsequently, a comb-drive actuator is introduced to tune the line shape of the transparency resonance. The width of the peak is reduced to 15 pm and the resulting quality factor exceeds 10(5).

  20. Monitoring the performance of the next Climate Forecast System version 3, throughout its development stage at EMC/NCEP

    NASA Astrophysics Data System (ADS)

    Peña, M.; Saha, S.; Wu, X.; Wang, J.; Tripp, P.; Moorthi, S.; Bhattacharjee, P.

    2016-12-01

    The next version of the operational Climate Forecast System (version 3, CFSv3) will be a fully coupled six-components system with diverse applications to earth system modeling, including weather and climate predictions. This system will couple the earth's atmosphere, land, ocean, sea-ice, waves and aerosols for both data assimilation and modeling. It will also use the NOAA Environmental Modeling System (NEMS) software super structure to couple these components. The CFSv3 is part of the next Unified Global Coupled System (UGCS), which will unify the global prediction systems that are now operational at NCEP. The UGCS is being developed through the efforts of dedicated research and engineering teams and through coordination across many CPO/MAPP and NGGPS groups. During this development phase, the UGCS is being tested for seasonal purposes and undergoes frequent revisions. Each new revision is evaluated to quickly discover, isolate and solve problems that negatively impact its performance. In the UGCS-seasonal model, components (e.g., ocean, sea-ice, atmosphere, etc.) are coupled through a NEMS-based "mediator". In this numerical infrastructure, model diagnostics and forecast validation are carried out, both component by component, and as a whole. The next stage, model optimization, will require enhanced performance diagnostics tools to help prioritize areas of numerical improvements. After the technical development of the UGCS-seasonal is completed, it will become the first realization of the CFSv3. All future development of this system will be carried out by the climate team at NCEP, in scientific collaboration with the groups that developed the individual components, as well as the climate community. A unique challenge to evaluate this unified weather-climate system is the large number of variables, which evolve over a wide range of temporal and spatial scales. A small set of performance measures and scorecard displays are been created, and collaboration and

  1. Interdependency Assessment of Coupled Natural Gas and Power Systems in Energy Market

    NASA Astrophysics Data System (ADS)

    Yang, Hongzhao; Qiu, Jing; Zhang, Sanhua; Lai, Mingyong; Dong, Zhao Yang

    2015-12-01

    Owing to the technological development of natural gas exploration and the increasing penetration of gas-fired power generation, gas and power systems inevitably interact with each other from both physical and economic points of view. In order to effectively assess the two systems' interdependency, this paper proposes a systematic modeling framework and constructs simulation platforms for coupled gas and power systems in an energy market environment. By applying the proposed approach to the Australian national electricity market (NEM) and gas market, the impacts of six types of market and system factors are quantitatively analyzed, including power transmission limits, gas pipeline contingencies, gas pipeline flow constraints, carbon emission constraints, power load variations, and non-electric gas load variations. The important interdependency and infrastructure weakness for the two systems are well studied and identified. Our work provides a quantitative basis for grid operators and policy makers to support and guide operation and investment decisions for electric power and natural gas industries.

  2. Analysis and Representation of Miscellaneous Electric Loads in NEMS

    EIA Publications

    2017-01-01

    Miscellaneous Electric Loads (MELs) comprise a growing portion of delivered energy consumption in residential and commercial buildings. Miscellaneous end uses—including televisions, personal computers, security systems, data center servers, and many other devices—have continued to penetrate into building-related market segments. Part of this proliferation of devices and equipment can be attributed to increased service demand for entertainment, computing, and convenience appliances.

  3. Carbon Nanofiber-Based, High-Frequency, High-Q, Miniaturized Mechanical Resonators

    NASA Technical Reports Server (NTRS)

    Kaul, Anupama B.; Epp, Larry W.; Bagge, Leif

    2011-01-01

    High Q resonators are a critical component of stable, low-noise communication systems, radar, and precise timing applications such as atomic clocks. In electronic resonators based on Si integrated circuits, resistive losses increase as a result of the continued reduction in device dimensions, which decreases their Q values. On the other hand, due to the mechanical construct of bulk acoustic wave (BAW) and surface acoustic wave (SAW) resonators, such loss mechanisms are absent, enabling higher Q-values for both BAW and SAW resonators compared to their electronic counterparts. The other advantages of mechanical resonators are their inherently higher radiation tolerance, a factor that makes them attractive for NASA s extreme environment planetary missions, for example to the Jovian environments where the radiation doses are at hostile levels. Despite these advantages, both BAW and SAW resonators suffer from low resonant frequencies and they are also physically large, which precludes their integration into miniaturized electronic systems. Because there is a need to move the resonant frequency of oscillators to the order of gigahertz, new technologies and materials are being investigated that will make performance at those frequencies attainable. By moving to nanoscale structures, in this case vertically oriented, cantilevered carbon nanotubes (CNTs), that have larger aspect ratios (length/thickness) and extremely high elastic moduli, it is possible to overcome the two disadvantages of both bulk acoustic wave (BAW) and surface acoustic wave (SAW) resonators. Nano-electro-mechanical systems (NEMS) that utilize high aspect ratio nanomaterials exhibiting high elastic moduli (e.g., carbon-based nanomaterials) benefit from high Qs, operate at high frequency, and have small force constants that translate to high responsivity that results in improved sensitivity, lower power consumption, and im - proved tunablity. NEMS resonators have recently been demonstrated using topdown

  4. Amygdala reactivity and negative emotionality: divergent correlates of antisocial personality and psychopathy traits in a community sample.

    PubMed

    Hyde, Luke W; Byrd, Amy L; Votruba-Drzal, Elizabeth; Hariri, Ahmad R; Manuck, Stephen B

    2014-02-01

    Previous studies have emphasized that antisocial personality disorder (APD) and psychopathy overlap highly but differ critically in several features, notably negative emotionality (NEM) and possibly amygdala reactivity to social signals of threat and distress. Here we examined whether dimensions of psychopathy and APD correlate differentially with NEM and amygdala reactivity to emotional faces. Testing these relationships among healthy individuals, dimensions of psychopathy and APD were generated by the profile matching technique of Lynam and Widiger (2001), using facet scales of the NEO Personality Inventory-Revised, and amygdala reactivity was measured using a well-established emotional faces task, in a community sample of 103 men and women. Higher psychopathy scores were associated with lower NEM and lower amygdala reactivity, whereas higher APD scores were related to greater NEM and greater amygdala reactivity, but only after overlapping variance in APD and psychopathy was adjusted for in the statistical model. Amygdala reactivity did not mediate the relationship of APD and psychopathy scores to NEM. Supplemental analyses also compared other measures of factors within psychopathy in predicting NEM and amygdala reactivity and found that Factor 2 psychopathy was positively related to NEM and amygdala reactivity across measures of psychopathy. The overall findings replicate seminal observations on NEM in psychopathy by Hicks and Patrick (2006) and extend this work to neuroimaging in a normative population. They also suggest that one critical way in which APD and psychopathy dimensions may differ in their etiology is through their opposing levels of NEM and amygdala reactivity to threat. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  5. Amygdala Reactivity and Negative Emotionality: Divergent Correlates of Antisocial Personality and Psychopathy Traits in a Community Sample

    PubMed Central

    Hyde, Luke W.; Byrd, Amy L.; Votruba-Drzal, Elizabeth; Hariri, Ahmad R.; Manuck, Stephen B.

    2014-01-01

    Previous studies have emphasized that antisocial personality disorder (APD) and psychopathy overlap highly but differ critically in several features, notably negative emotionality (NEM) and possibly amygdala reactivity to social signals of threat and distress. Here we examined whether dimensions of psychopathy and APD correlate differentially with NEM and amygdala reactivity to emotional faces. Testing these relationships among healthy individuals, dimensions of psychopathy and APD were generated by the profile matching technique of Lynam and Widiger (2001), using facet scales of the NEO Personality Inventory-Revised, and amygdala reactivity was measured using a well-established emotional faces task, in a community sample of 103 men and women. Higher psychopathy scores were associated with lower NEM and lower amygdala reactivity, whereas higher APD scores were related to greater NEM and greater amygdala reactivity, but only after overlapping variance in APD and psychopathy was adjusted for in the statistical model. Amygdala reactivity did not mediate the relationship of APD and psychopathy scores to NEM. Supplemental analyses also compared other measures of factors within psychopathy in predicting NEM and amygdala reactivity and found that Factor 2 psychopathy was positively related to NEM and amygdala reactivity across measures of psychopathy. The overall findings replicate seminal observations on NEM in psychopathy by Hicks and Patrick (2006) and extend this work to neuroimaging in a normative population. They also suggest that one critical way in which APD and psychopathy dimensions may differ in their etiology is through their opposing levels of NEM and amygdala reactivity to threat. PMID:24661171

  6. Comprehensive Electricity Competition Act: A Comparison of Model Results, The

    EIA Publications

    1999-01-01

    This report describes the Energy Information Administration's use of the National Energy Modeling System (NEMS) to evaluate the effects of the Administration's restructuring proposal using the parameter settings and assumptions from the Policy Office Electricity Modeling System (POEMS) analysis.

  7. Youth at ultra high risk for psychosis: using the Revised Network Episode Model to examine pathways to mental health care.

    PubMed

    Boydell, Katherine M; Volpe, Tiziana; Gladstone, Brenda M; Stasiulis, Elaine; Addington, Jean

    2013-05-01

    This paper aims to identify the ways in which youth at ultra high risk for psychosis access mental health services and the factors that advance or delay help seeking, using the Revised Network Episode Model (REV NEM) of mental health care. A case study approach documents help-seeking pathways, encompassing two qualitative interviews with 10 young people and 29 significant others. Theoretical propositions derived from the REV NEM are explored, consisting of the content, structure and function of the: (i) family; (ii) community and school; and (iii) treatment system. Although the aspects of the REV NEM are supported and shape pathways to care, we consider rethinking the model for help seeking with youth at ultra high risk for psychosis. The pathway concept is important to our understanding of how services and supports are received and experienced over time. Understanding this process and the strategies that support positive early intervention on the part of youth and significant others is critical. © 2012 Wiley Publishing Asia Pty Ltd.

  8. Agricultural residue availability in the United States.

    PubMed

    Haq, Zia; Easterly, James L

    2006-01-01

    The National Energy Modeling System (NEMS) is used by the Energy Information Administration (EIA) to forecast US energy production, consumption, and price trends for a 25-yr-time horizon. Biomass is one of the technologies within NEMS, which plays a key role in several scenarios. An endogenously determined biomass supply schedule is used to derive the price-quantity relationship of biomass. There are four components to the NEMS biomass supply schedule including: agricultural residues, energy crops, forestry residues, and urban wood waste/mill residues. The EIA's Annual Energy Outlook 2005 includes updated estimates of the agricultural residue portion of the biomass supply schedule. The changes from previous agricultural residue supply estimates include: revised assumptions concerning corn stover and wheat straw residue availabilities, inclusion of non-corn and non-wheat agricultural residues (such as barley, rice straw, and sugarcane bagasse), and the implementation of assumptions concerning increases in no-till farming. This article will discuss the impact of these changes on the supply schedule.

  9. Single-crystalline monolayer and multilayer graphene nano switches

    NASA Astrophysics Data System (ADS)

    Li, Peng; Jing, Gaoshan; Zhang, Bo; Sando, Shota; Cui, Tianhong

    2014-03-01

    Growth of monolayer, bi-layer, and tri-layer single-crystalline graphene (SCG) using chemical vapor deposition method is reported. SCG's mechanical properties and single-crystalline nature were characterized and verified by atomic force microscope and Raman spectroscopy. Electro-mechanical switches based on mono- and bi-layer SCG were fabricated, and the superb properties of SCG enable the switches to operate at pull-in voltage as low as 1 V, and high switching speed about 100 ns. These devices exhibit lifetime without a breakdown of over 5000 cycles, far more durable than any other graphene nanoelectromechanical system switches reported.

  10. Single-crystalline monolayer and multilayer graphene nano switches

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Li, Peng; Cui, Tianhong, E-mail: tcui@me.umn.edu; Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455

    2014-03-17

    Growth of monolayer, bi-layer, and tri-layer single-crystalline graphene (SCG) using chemical vapor deposition method is reported. SCG's mechanical properties and single-crystalline nature were characterized and verified by atomic force microscope and Raman spectroscopy. Electro-mechanical switches based on mono- and bi-layer SCG were fabricated, and the superb properties of SCG enable the switches to operate at pull-in voltage as low as 1 V, and high switching speed about 100 ns. These devices exhibit lifetime without a breakdown of over 5000 cycles, far more durable than any other graphene nanoelectromechanical system switches reported.

  11. Model documentation report: Transportation sector model of the National Energy Modeling System

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Not Available

    1994-03-01

    This report documents the objectives, analytical approach and development of the National Energy Modeling System (NEMS) Transportation Model (TRAN). The report catalogues and describes the model assumptions, computational methodology, parameter estimation techniques, model source code, and forecast results generated by the model. This document serves three purposes. First, it is a reference document providing a detailed description of TRAN for model analysts, users, and the public. Second, this report meets the legal requirements of the Energy Information Administration (EIA) to provide adequate documentation in support of its statistical and forecast reports (Public Law 93-275, 57(b)(1)). Third, it permits continuity inmore » model development by providing documentation from which energy analysts can undertake model enhancements, data updates, and parameter refinements.« less

  12. Impacts of Modeled Recommendations of the National Commission on Energy Policy

    EIA Publications

    2005-01-01

    This report provides the Energy Information Administration's analysis of those National Commission on Energy Policy (NCEP) energy policy recommendations that could be simulated using the National Energy Modeling System (NEMS).

  13. Impact of Unconventional Gas Technology in the Annual Energy Outlook 2000

    EIA Publications

    2000-01-01

    This paper describes the methodology used in the National Energy Modeling System (NEMS) to represent unconventional gas technologies and their impacts on projections in the Annual Energy Outlook 2000 (AEO2000).

  14. Analysis of FERC's Final EIS for Electricity Open Access & Recovery of Stranded Costs

    EIA Publications

    1996-01-01

    Reviews the Final Environmental Impact Statement (FEIS) prepared by the Federal Energy Regulatory Commission for its electricity transmission system open access prepared in April 1996 and uses the National Energy Modeling System (NEMS) to analyze the open access rule (Orders 888 and 889).

  15. SHORT RANGE ENSEMBLE Products

    Science.gov Websites

    - CONUS Double Resolution (Lambert Conformal - 40km) NEMS Non-hydrostatic Multiscale Model on the B grid AWIPS grid 212 Regional - CONUS Double Resolution (Lambert Conformal - 40km) NEMS Non-hydrostatic 132 - Double Resolution (Lambert Conformal - 16km) NEMS Non-hydrostatic Multiscale Model on the B grid

  16. High Volume Manufacturing and Field Stability of MEMS Products

    NASA Astrophysics Data System (ADS)

    Martin, Jack

    Low volume MEMS/NEMS production is practical when an attractive concept is implemented with business, manufacturing, packaging, and test support. Moving beyond this to high volume production adds requirements on design, process control, quality, product stability, market size, market maturity, capital investment, and business systems. In a broad sense, this chapter uses a case study approach: It describes and compares the silicon-based MEMS accelerometers, pressure sensors, image projection systems, and gyroscopes that are in high volume production. Although they serve several markets, these businesses have common characteristics. For example, the manufacturing lines use automated semiconductor equipment and standard material sets to make consistent products in large quantities. Standard, well controlled processes are sometimes modified for a MEMS product. However, novel processes that cannot run with standard equipment and material sets are avoided when possible. This reliance on semiconductor tools, as well as the organizational practices required to manufacture clean, particle-free products partially explains why the MEMS market leaders are integrated circuit manufacturers. There are other factors. MEMS and NEMS are enabling technologies, so it can take several years for high volume applications to develop. Indeed, market size is usually a strong function of price. This becomes a vicious circle, because low price requires low cost - a result that is normally achieved only after a product is in high volume production. During the early years, IC companies reduced cost and financial risk by using existing facilities for low volume MEMS production. As a result, product architectures are partially determined by capabilities developed for previous products. This chapter includes a discussion of MEMS product architecture with particular attention to the impact of electronic integration, packaging, and surfaces. Packaging and testing are critical, because they are

  17. High Volume Manufacturing and Field Stability of MEMS Products

    NASA Astrophysics Data System (ADS)

    Martin, Jack

    Low volume MEMS/NEMS production is practical when an attractive concept is implemented with business, manufacturing, packaging, and test support. Moving beyond this to high volume production adds requirements on design, process control, quality, product stability, market size, market maturity, capital investment, and business systems. In a broad sense, this chapter uses a case study approach: It describes and compares the silicon-based MEMS accelerometers, pressure sensors, image projection systems, and gyroscopes that are in high volume production. Although they serve several markets, these businesses have common characteristics. For example, the manufacturing lines use automated semiconductor equipment and standard material sets to make consistent products in large quantities. Standard, well controlled processes are sometimes modified for a MEMS product. However, novel processes that cannot run with standard equipment and material sets are avoided when possible. This reliance on semiconductor tools, as well as the organizational practices required to manufacture clean, particle-free products partially explains why the MEMS market leaders are integrated circuit manufacturers. There are other factors. MEMS and NEMS are enabling technologies, so it can take several years for high volume applications to develop. Indeed, market size is usually a strong function of price. This becomes a vicious circle, because low price requires low cost - a result that is normally achieved only after a product is in high volume production. During the early years, IC companies reduced cost and financial risk by using existing facilities for low volume MEMS production. As a result, product architectures are partially determined by capabilities developed for previous products. This chapter includes a discussion of MEMS product architecture with particular attention to the impact of electronic integration, packaging, and surfaces. Packaging and testing are critical, because they are

  18. KCl cotransport regulation and protein kinase G in cultured vascular smooth muscle cells.

    PubMed

    Adragna, N C; Zhang, J; Di Fulvio, M; Lincoln, T M; Lauf, P K

    2002-05-15

    K-Cl cotransport is activated by vasodilators in erythrocytes and vascular smooth muscle cells and its regulation involves putative kinase/phosphatase cascades. N-ethylmaleimide (NEM) activates the system presumably by inhibiting a protein kinase. Nitrovasodilators relax smooth muscle via cGMP-dependent activation of protein kinase G (PKG), a regulator of membrane channels and transporters. We investigated whether PKG regulates K-Cl cotransport activity or mRNA expression in normal, PKG-deficient-vector-only-transfected (PKG-) and PKG-catalytic-domain-transfected (PKG+) rat aortic smooth muscle cells. K-Cl cotransport was calculated as the Cl-dependent Rb influx, and mRNA was determined by semiquantitative RT-PCR. Baseline K-Cl cotransport was higher in PKG+ than in PKG- cells (p <0.01). At 0.5 mM, NEM stimulated K-Cl cotransport by 5-fold in PKG- but not in PKG+ cells. However, NEM was more potent although less effective to activate K-Cl cotransport in normal (passage 1-3) and PKG+ than in PKG- cells. In PKG- cells, [(dihydroindenyl) oxy] alkanoic acid (300 mM) but not furosemide (1 mM) inhibited K-Cl cotransport. Furthermore, no difference in K-Cl cotransport mRNA expression was observed between these cells. In conclusion, this study shows that manipulation of PKG expression in vascular smooth muscle cells affects K-Cl cotransport activity and its activation by NEM.

  19. NEMS (Nanoelectromechanicsl Systems) Networks: A Novel Validation Platform for Controlling Interconnected Dynamical Networks

    DTIC Science & Technology

    2015-08-01

    power   power  grids  to...both  an   ultralow  intrinsic  dissipation   (high  Q)  and  a  low  threshold  onset  of  nonlinear  dynamics.  Q...of   nodes,   we  will   have   in   effect   a   powerful   simulator   for   large-­‐scale   real   world  

  20. A techno-economic assessment of grid connected photovoltaic system for hospital building in Malaysia

    NASA Astrophysics Data System (ADS)

    Mat Isa, Normazlina; Tan, Chee Wei; Yatim, AHM

    2017-07-01

    Conventionally, electricity in hospital building are supplied by the utility grid which uses mix fuel including coal and gas. Due to enhancement in renewable technology, many building shall moving forward to install their own PV panel along with the grid to employ the advantages of the renewable energy. This paper present an analysis of grid connected photovoltaic (GCPV) system for hospital building in Malaysia. A discussion is emphasized on the economic analysis based on Levelized Cost of Energy (LCOE) and total Net Present Post (TNPC) in regards with the annual interest rate. The analysis is performed using Hybrid Optimization Model for Electric Renewables (HOMER) software which give optimization and sensitivity analysis result. An optimization result followed by the sensitivity analysis also being discuss in this article thus the impact of the grid connected PV system has be evaluated. In addition, the benefit from Net Metering (NeM) mechanism also discussed.

  1. Annual Energy Outlook 2016 With Projections to 2040

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    None, None

    The Annual Energy Outlook 2016 (AEO2016), prepared by the U.S. Energy Information Administration (EIA), presents long-term projections of energy supply, demand, and prices through 2040. The projections, focused on U.S. energy markets, are based on results from EIA’s National Energy Modeling System (NEMS). NEMS enables EIA to make projections under alternative, internallyconsistent sets of assumptions. The analysis in AEO2016 focuses on the Reference case and 17 alternative cases. EIA published an Early Release version of the AEO2016 Reference case (including U.S. Environmental Protection Agency’s (EPA) Clean Power Plan (CPP)) and a No CPP case (excluding the CPP) in May 2016.

  2. Assumptions to the annual energy outlook 1999 : with projections to 2020

    DOT National Transportation Integrated Search

    1998-12-16

    This paper presents the major assumptions of the National Energy Modeling System (NEMS) used to : generate the projections in the Annual Energy Outlook 19991 (AEO99), including general features of : the model structure, assumptions concerning energy ...

  3. Assumptions to the annual energy outlook 2000 : with projections to 2020

    DOT National Transportation Integrated Search

    2000-01-01

    This paper presents the major assumptions of the National Energy Modeling System (NEMS) used to : generate the projections in the Annual Energy Outlook 20001 (AEO2000), including general features of : the model structure, assumptions concerning energ...

  4. Assumptions to the annual energy outlook 2001 : with projections to 2020

    DOT National Transportation Integrated Search

    2000-12-01

    This report presents the major assumptions of the National Energy Modeling System (NEMS) used to : generate the projections in the Annual Energy Outlook 20011 (AEO2001), including general features of : the model structure, assumptions concerning ener...

  5. Assumptions for the annual energy outlook 2003 : with projections to 2025

    DOT National Transportation Integrated Search

    2003-01-01

    This report presents the major assumptions of the National Energy Modeling System (NEMS) used to : generate the projections in the Annual Energy Outlook 20031 (AEO2003), including general features of : the model structure, assumptions concerning ener...

  6. A COMPARATIVE ANALYSIS OF NUTRIENT LOADING, NUTRIENT RETENTION AND NET ECOSYSTEM METABOLISM IN THREE TIDAL RIVER ESTUARIES DIFFERING PREDOMINATELY BY THEIR WATERSHED LAND USE TYPES.

    EPA Science Inventory

    Abstract and oral presentation for the Estuarine Research Federation Conference.

    Estuarine retention of watershed nutrient loads, system-wide nutrient biogeochemical fluxes, and net ecosystem metabolism (NEM) were determined in three estuaries exhibiting differing magnitud...

  7. One‐Dimensional Ferroelectric Nanostructures: Synthesis, Properties, and Applications

    PubMed Central

    Liang, Longyue; Kang, Xueliang

    2016-01-01

    One‐dimensional (1D) ferroelectric nanostructures, such as nanowires, nanorods, nanotubes, nanobelts, and nanofibers, have been studied with increasing intensity in recent years. Because of their excellent ferroelectric, ferroelastic, pyroelectric, piezoelectric, inverse piezoelectric, ferroelectric‐photovoltaic (FE‐PV), and other unique physical properties, 1D ferroelectric nanostructures have been widely used in energy‐harvesting devices, nonvolatile random access memory applications, nanoelectromechanical systems, advanced sensors, FE‐PV devices, and photocatalysis mechanisms. This review summarizes the current state of 1D ferroelectric nanostructures and provides an overview of the synthesis methods, properties, and practical applications of 1D nanostructures. Finally, the prospects for future investigations are outlined. PMID:27812477

  8. Catalytic chemical vapor deposition synthesis and electron microscopy observation of coiled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Xie, Jining; Mukhopadyay, K.; Yadev, J.; Varadan, V. K.

    2003-10-01

    Coiled carbon nanotubes exhibit excellent mechanical and electrical properties because of the combination of coil morphology and properties of nanotubes. They could have potential novel applications in nanocomposites and nano-electronic devices as well as nano-electromechanical systems. In this work, synthesis of regularly coiled carbon nanotubes is presented. It involves pyrolysis of hydrocarbon gas over metal/support catalyst by both thermal filament and microwave catalytic chemical vapor deposition methods. Scanning electron microscopy and transmission electron microscopy were performed to observe the coil morphology and nanostructure of coiled nanotubes. The growth mechanism and structural and electrical properties of coiled carbon nanotubes are also discussed.

  9. Sulfhydryl blocker-induced colitis in the rat: immunological changes in thymus gland and colonic mucosa.

    PubMed

    Suzuki, H; Hibi, T; Oda, M; Hosoda, Y; Mori, M; Miura, S; Tanaka, S; Watanabe, M; Tsuchiya, M

    1994-01-01

    The study was designed to examine the changes of thymus in sulfhydryl blocker-induced colitis. We used N-ethylmaleimide (NEM) as sulfhydryl blockers. Fasted male Sprague-Dawley rats were given 3% NEM in 1% methyl cellulose into the colon. N-ethylmaleimide treatment caused severe diarrhoea with bleeding for the first 7 days. At autopsy, adhesions, colon dilatation, and single or multiple erosions and ulcers were observed. Time-course studies revealed that the lesions were most extensive and severe 3 or 7 days after the administration of NEM. Histological examination of colon on the 3rd day after NEM treatment demonstrated mucosal erosion, oedema and extensive infiltration of neutrophils. The mucosal lesions extended into the submucosa and muscle on the 7th day after NEM treatment. Immunohistochemical studies showed that T cells and macrophages were markedly increased in the lamina propria of colonic mucosa. After 3 weeks, the infiltration of chronic inflammatory cells was observed and regeneration of the mucosa was noticed. The thymus gland was significantly decreased in weight and size on the 3rd day after NEM treatment, but the weight loss of thymus gland was regained in 3 weeks. Transient atrophy of thymus gland was noticed in this colitis model. The phenotypes of thymocytes were not influenced by NEM treatment. It is concluded that the thymus abnormalities in human ulcerative colitis are not induced in this animal model and that other chronic models are necessary for the elucidation of the immunological abnormalities, including thymus abnormalities.

  10. Levelized Cost and Levelized Avoided Cost of New Generation Resources in the Annual Energy Outlook

    EIA Publications

    2017-01-01

    This paper presents average values of levelized costs for generating technologies entering service in 2019, 2022, and 2040 as represented in the National Energy Modeling System (NEMS) for the Annual Energy Outlook 2017 (AEO2017) Reference case.

  11. A Theory-Based Contextual Nutrition Education Manual Enhanced Nutrition Teaching Skill.

    PubMed

    Kupolati, Mojisola D; MacIntyre, Una E; Gericke, Gerda J

    2018-01-01

    Background: A theory-based contextual nutrition education manual (NEM) may enhance effective teaching of nutrition in schools. School nutrition education should lead to the realization of such benefits as improved health, scholarly achievement leading to manpower development and consequently the nation's development. The purpose of the study was to develop a contextual NEM for teachers of Grade 5 and 6 learners in the Bronkhorstspruit district, South Africa, and to assess teachers' perception on the use of the manual for teaching nutrition. Methods: This descriptive case study used an interpretivist paradigm. The study involved teachers ( N = 6) who taught nutrition in Life Skills (LS) and Natural Science and Technology (NST) in a randomly selected primary school in the Bronkhorstspruit district. Findings from a nutrition education needs assessment were integrated with the constructs of the Social cognitive theory (SCT) and the Meaningful learning model (MLM) and the existing curriculum of the Department of Basic Education (DoBE) to develop a contextual NEM. The manual was used by the teachers to teach nutrition to Grades 5 and 6 learners during the 2015 academic year as a pilot project. A focus group discussion (FDG) was conducted with teachers to gauge their perceptions of the usefulness of the NEM. Data were analyzed using the thematic approach of the framework method for qualitative research. Results: Teachers described the NEM as rich in information, easy to use and perceived the supporting materials and activities as being effective. The goal setting activities contained in the NEM were deemed to be ineffective. Teachers felt that they did not have enough time to teach all the important things that the learners needed to know. Conclusion: Teachers perceived the NEM as helpful toward improving their nutrition teaching skills.The NEM template may furthermore guide teachers in planning theory-based nutrition lessons.

  12. Effect of a formulation of Bacillus firmus on root-knot nematode Meloidogyne incognita infestation and the growth of tomato plants in the greenhouse and nursery.

    PubMed

    Terefe, Metasebia; Tefera, Tadele; Sakhuja, P K

    2009-02-01

    Bacillus firmus, commercial WP formulation (BioNem) was evaluated against the root-knot nematode Meloidogyne incognita in a laboratory, greenhouse and under field conditions on tomato plants. In the laboratory tests, an aqueous suspension of BioNem at 0.5%, 1%, 1.5% and 2% concentration reduced egg hatching from 98% to 100%, 24-days after treatment. Treatment of second-stage juveniles with 2.5% and 3% concentration of BioNem, caused 100% inhibition of mobility, 24 h after treatment. In the green house trials, BioNem applied at 8 g/pot (1200 cc soil) planted with a tomato seedlings reduced gall formation by 91%, final nematode populations by 76% and the number of eggs by 45%. Consequently, plant height and biomass was increased by 71% and 50%, respectively, compared to the untreated control, 50-days after treatment application. Application of BioNem at 16 g/pot was phytotoxic to plants. In the field trails, BioNem applied at 200 and 400 kg ha(-1) was effective in reducing the number of galls (75-84%), and increased shoot height (29-31%) and weight (20-24%) over the untreated control, 45-days after treatment. Our results indicate that B. firmus is a promising microorganism for the biological control of M. incognita in tomato pots.

  13. Protecting patients with cardiovascular diseases from catastrophic health expenditure and impoverishment by health finance reform.

    PubMed

    Sun, Jing; Liabsuetrakul, Tippawan; Fan, Yancun; McNeil, Edward

    2015-12-01

    To compare the incidences of catastrophic health expenditure (CHE) and impoverishment, the risk protection offered by two health financial reforms and to explore factors associated with CHE and impoverishment among patients with cardiovascular diseases (CVDs) in rural Inner Mongolia, China. Cross-sectional study conducted in 2014 in rural Inner Mongolia, China. Patients with CVDs aged over 18 years residing in the sample areas for at least one year were eligible. The definitions of CHE and impoverishment recommended by WHO were adopted. The protection of CHE and impoverishment was compared between the New Cooperative Medical Scheme (NCMS) alone and NCMS plus National Essential Medicines Scheme (NEMS) using the percentage change of incidences for CHE and impoverishment. Logistic regression was used to explore factors associated with CHE and impoverishment. The incidences of CHE and impoverishment under NCMS plus NEMS were 11.26% and 3.30%, respectively, which were lower than those under NCMS alone. The rates of protection were higher among households with patients with CVDs covered by NCMS plus NEMS (25.68% and 34.65%, respectively). NCMS plus NEMS could protect the poor households more from CHE but not impoverishment. NCMS plus NEMS protected more than one-fourth of households from CHE and more than one-third from impoverishment. NCMS plus NEMS was more effective at protecting households with patients with CVDs from CHE and impoverishment than NCMS alone. An integration of NCMS with NEMS should be expanded. However, further strategies to minimise catastrophic health expenditure after this health finance reform are still needed. © 2015 John Wiley & Sons Ltd.

  14. Degradation of native and modified forms of fructose-bisphosphate aldolase microinjected into HeLa cells.

    PubMed Central

    Hopgood, M F; Knowles, S E; Bond, J S; Ballard, F J

    1988-01-01

    The uptake and degradation of radiolabelled rabbit muscle fructose-bisphosphate aldolase (EC 4.1.2.13) was studied in HeLa cells microinjected by the erythrocyte ghost fusion system. Labelled aldolase was progressively modified by treatment with GSSG or N-ethylmaleimide (NEM) before microinjection to determine whether these agents, which inactivate and destabilize the enzyme in vitro, affect the half-life of the enzyme in vivo. Increasing exposure of aldolase to GSSG or NEM before microinjection increased the extent of aldolase transfer into the HeLa cells and decreased the proportion of the protein that could be extracted from the cells after water lysis. Some degradation of the GSSG- and NEM-inactivated aldolases was observed in the ghosts before microinjection; thus a family of radiolabelled proteins was microinjected in these experiments. In spite of the above differences, the 40 kDa subunit of each aldolase form was degraded with a half-life of 30 h in the HeLa cells. In contrast, the progressively modified forms of aldolase were increasingly susceptible to proteolytic action in vitro by chymotrypsin or by cathepsin B and in ghosts. These studies indicate that the rate of aldolase degradation in cells is not determined by attack by cellular proteinases that recognize vulnerable protein substrates; the results are most easily explained by a random autophagic process involving the lysosomal system. Images Fig. 3. Fig. 7. PMID:3223914

  15. Effect of N-Ethylmaleimide as a Blocker of Disulfide Crosslinks Formation on the Alkali-Cold Gelation of Whey Proteins

    PubMed Central

    Lei, Zhao; Chen, Xiao Dong

    2016-01-01

    N-ethylmaleimide (NEM) was used to verify that no new disulfide crosslinks were formed during the fascinating rheology of the alkali cold-gelation of whey proteins, which show Sol-Gel-Sol transitions with time at pH > 11.5. These dynamic transitions involve the formation and subsequent destruction of non-covalent interactions between soluble whey aggregates. Therefore, incubation of aggregates with NEM was expected not to affect much the rheology. Experiments show that very little additions of NEM, such as 0.5 mol per mol of protein, delayed and significantly strengthened the metastable gels formed. Interactions between whey protein aggregates were surprisingly enhanced during incubation with NEM as inferred from oscillatory rheometry at different protein concentrations, dynamic swelling, Trp fluorescence and SDS-PAGE measurements. PMID:27732644

  16. Free vibration investigation of nano mass sensor using differential transformation method

    NASA Astrophysics Data System (ADS)

    Zarepour, Misagh; Hosseini, S. Amirhosein; Ghadiri, Majid

    2017-03-01

    In the present study, transverse vibration of nano-cantilever beam with attached mass and two rotational and transverse springs at its end is studied. Resonance frequency of vibrating system is influenced by changing mass particle and stiffness coefficients. Euler-Bernoulli beam theory, nonlocal constitutive equations of Eringen, and Hamilton's principle are used to develop equations of motion. Differential transformation method (DTM) is applied to solve the governing equations of the nanobeam with attached mass particle. Accurate results with minimum mathematical calculation are the advantages of DTM. A detailed parametric study is conducted to investigate the influences of nonlocal parameter. The results can be used in designing of nanoelectromechanical systems. To verify the results, some comparisons are presented between differential transform method results and open literature to show the accuracy of this new approach.

  17. A novel mobile phone application to assess nutrition environment measures in low- and middle-income countries.

    PubMed

    Kanter, Rebecca; Alvey, Jeniece; Fuentes, Deborah

    2014-09-01

    Consumer nutrition environment measures are important to understanding the food environment, which affects individual dietary intake. A nutrition environment measures survey for supermarkets (NEMS-S) has been designed on paper for use in Guatemala. However, a paper survey is not an inconspicuous data collection method. To design, pilot test, and validate the Guatemala NEMS-S in the form of a mobile phone application (mobile app). CommCare, a free and open-source software application, was used to design the NEMS-S for Guatemala in the form of a mobile app. Two raters tested the mobile app in a single Guatemalan supermarket. Both the interrater and the test-retest reliability of the mobile app were determined using percent agreement and Cohen's kappa score and compared with the interrater and test-retest reliability of the paper version. Interrater reliability was very high between the paper survey and the mobile app (Cohen's kappa > 0.90). Test-retest reliability ranged from kappa 0.78 to 0.91. Between two certified NEMS-S raters, survey completion time using the mobile app was 5 minutes less than that with the paper form (35 vs. 40 minutes). The NEMS-S mobile app provides for more rapid data collection, with equivalent reliability and validity to the NEMS-S paper version, with advantages over a paper-based survey of multiple language capability and concomitant data entry.

  18. Evaluation of the nursing workload through the Nine Equivalents for Nursing Manpower Use Scale and the Nursing Activities Score: a prospective correlation study.

    PubMed

    Carmona-Monge, Francisco Javier; Rollán Rodríguez, Gloria Ma; Quirós Herranz, Cristina; García Gómez, Sonia; Marín-Morales, Dolores

    2013-08-01

    To determine the relationship between nursing workload measured through the nine equivalents of nursing manpower use (NEMS) scale and that measured through the nursing activities score (NAS) scale and to analyse staff needs as determined through each of the scales. The study used a descriptive prospective correlational design to collect data between October 2007 and July 2009. Nursing workload data for 730 ICU patients were collected daily using the NAS and NEMS scales. Both scales were then correlated and used to estimate staff needs. 6815 score pairs were collected, which reflected the nursing workload for each patient as calculated daily using both scales. Pearson's correlation coefficient for individual measurements obtained through the NAS and the NEMS corresponded to .672, and to .932 for the daily total workload in the unit. The staffing requirements based on the NAS scale scores were significantly higher than those based on the NEMS scale. A high correlation existed for individual measurements using both scales and for the total workload measurement in the unit. The main difference was found when analysing staffing requirements, with higher staff numbers needed for the NAS scale. Both NAS and NEMS can be used to measure the nursing workload in the ICU. Staffing requirements using NAS were higher than those using NEMS. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. N-ethylmaleimide activates a Cl−-independent component of K+ flux in mouse erythrocytes

    PubMed Central

    Shmukler, Boris E.; Hsu, Ann; Alves, Jessica; Trudel, Marie; Rust, Marco B.; Hubner, Christian A.; Rivera, Alicia; Alper, Seth L.

    2013-01-01

    The K-Cl cotransporters (KCCs) of mouse erythrocytes exhibit higher basal activity than those of human erythrocytes, but are similarly activated by cell swelling, by hypertonic urea, and by staurosporine. However, the dramatic stimulation of human erythroid KCCs by N-ethylmaleimide (NEM) is obscured in mouse erythrocytes by a prominent NEM-stimulated K+ efflux that lacks Cl−-dependence. The NEM-sensitivity of Cl−-independent K+ efflux of mouse erythrocytes is lower than that of KCC. The genetically engineered absence of the K-Cl cotransporters KCC3 and KCC1 from mouse erythrocytes does not modify Cl−-independent K+ efflux. Mouse erythrocytes genetically devoid of the Gardos channel KCNN4 show increased NEM-sensitivity of both Cl−-independent K+ efflux and K-Cl cotransport. The increased NEM-sensitivity and stimulation magnitude of Cl−-independent K+ efflux in mouse erythrocytes expressing transgenic hypersickling human hemoglobin SAD (HbSAD) is independent of the presence of KCC3 and KCC1, but absence of KCNN4 reduces the stimulatory effect of HbSAD. NEM-stimulated Cl−-independent K+ efflux of mouse red cells is insensitive to ouabain and bumetanide, but partially inhibited by chloroquine, barium, and amiloride. The NEM-stimulated activity is modestly reduced at pH 6.0, but not significantly altered at pH 8.0, and abolished at 0°C. Although the molecular identity of this little-studied K+ efflux pathway of mouse erythrocytes remains unknown, it’s potential role in the pathophysiology of sickle red cell dehydration will be important for extrapolation of studies in mouse models of sickle cell disease to our understanding of humans with sickle cell anemia. PMID:23481459

  20. Quantifying the Contribution of Entire Free-Living Nematode Communities to Carbon Mineralization under Contrasting C and N Availability

    PubMed Central

    Gebremikael, Mesfin Tsegaye; Steel, Hanne; Bert, Wim; Maenhout, Peter; Sleutel, Steven; De Neve, Stefaan

    2015-01-01

    To understand the roles of nematodes in organic matter (OM) decomposition, experimental setups should include the entire nematode community, the native soil microflora, and their food sources. Yet, published studies are often based on either simplified experimental setups, using only a few selected species of nematode and their respective prey, despite the multitude of species present in natural soil, or on indirect estimation of the mineralization process using O2 consumption and the fresh weight of nematodes. We set up a six-month incubation experiment to quantify the contribution of the entire free living nematode community to carbon (C) mineralization under realistic conditions. The following treatments were compared with and without grass-clover amendment: defaunated soil reinoculated with the entire free living nematode communities (+Nem) and defaunated soil that was not reinoculated (-Nem). We also included untreated fresh soil as a control (CTR). Nematode abundances and diversity in +Nem was comparable to the CTR showing the success of the reinoculation. No significant differences in C mineralization were found between +Nem and -Nem treatments of the amended and unamended samples at the end of incubation. Other related parameters such as microbial biomass C and enzymatic activities did not show significant differences between +Nem and -Nem treatments in both amended and unamended samples. These findings show that the collective contribution of the entire nematode community to C mineralization is small. Previous reports in literature based on simplified experimental setups and indirect estimations are contrasting with the findings of the current study and further investigations are needed to elucidate the extent and the mechanisms of nematode involvement in C mineralization. PMID:26393517

  1. THE EARTH SYSTEM PREDICTION SUITE: Toward a Coordinated U.S. Modeling Capability

    PubMed Central

    Theurich, Gerhard; DeLuca, C.; Campbell, T.; Liu, F.; Saint, K.; Vertenstein, M.; Chen, J.; Oehmke, R.; Doyle, J.; Whitcomb, T.; Wallcraft, A.; Iredell, M.; Black, T.; da Silva, AM; Clune, T.; Ferraro, R.; Li, P.; Kelley, M.; Aleinov, I.; Balaji, V.; Zadeh, N.; Jacob, R.; Kirtman, B.; Giraldo, F.; McCarren, D.; Sandgathe, S.; Peckham, S.; Dunlap, R.

    2017-01-01

    The Earth System Prediction Suite (ESPS) is a collection of flagship U.S. weather and climate models and model components that are being instrumented to conform to interoperability conventions, documented to follow metadata standards, and made available either under open source terms or to credentialed users. The ESPS represents a culmination of efforts to create a common Earth system model architecture, and the advent of increasingly coordinated model development activities in the U.S. ESPS component interfaces are based on the Earth System Modeling Framework (ESMF), community-developed software for building and coupling models, and the National Unified Operational Prediction Capability (NUOPC) Layer, a set of ESMF-based component templates and interoperability conventions. This shared infrastructure simplifies the process of model coupling by guaranteeing that components conform to a set of technical and semantic behaviors. The ESPS encourages distributed, multi-agency development of coupled modeling systems, controlled experimentation and testing, and exploration of novel model configurations, such as those motivated by research involving managed and interactive ensembles. ESPS codes include the Navy Global Environmental Model (NavGEM), HYbrid Coordinate Ocean Model (HYCOM), and Coupled Ocean Atmosphere Mesoscale Prediction System (COAMPS®); the NOAA Environmental Modeling System (NEMS) and the Modular Ocean Model (MOM); the Community Earth System Model (CESM); and the NASA ModelE climate model and GEOS-5 atmospheric general circulation model. PMID:29568125

  2. THE EARTH SYSTEM PREDICTION SUITE: Toward a Coordinated U.S. Modeling Capability.

    PubMed

    Theurich, Gerhard; DeLuca, C; Campbell, T; Liu, F; Saint, K; Vertenstein, M; Chen, J; Oehmke, R; Doyle, J; Whitcomb, T; Wallcraft, A; Iredell, M; Black, T; da Silva, A M; Clune, T; Ferraro, R; Li, P; Kelley, M; Aleinov, I; Balaji, V; Zadeh, N; Jacob, R; Kirtman, B; Giraldo, F; McCarren, D; Sandgathe, S; Peckham, S; Dunlap, R

    2016-07-01

    The Earth System Prediction Suite (ESPS) is a collection of flagship U.S. weather and climate models and model components that are being instrumented to conform to interoperability conventions, documented to follow metadata standards, and made available either under open source terms or to credentialed users. The ESPS represents a culmination of efforts to create a common Earth system model architecture, and the advent of increasingly coordinated model development activities in the U.S. ESPS component interfaces are based on the Earth System Modeling Framework (ESMF), community-developed software for building and coupling models, and the National Unified Operational Prediction Capability (NUOPC) Layer, a set of ESMF-based component templates and interoperability conventions. This shared infrastructure simplifies the process of model coupling by guaranteeing that components conform to a set of technical and semantic behaviors. The ESPS encourages distributed, multi-agency development of coupled modeling systems, controlled experimentation and testing, and exploration of novel model configurations, such as those motivated by research involving managed and interactive ensembles. ESPS codes include the Navy Global Environmental Model (NavGEM), HYbrid Coordinate Ocean Model (HYCOM), and Coupled Ocean Atmosphere Mesoscale Prediction System (COAMPS ® ); the NOAA Environmental Modeling System (NEMS) and the Modular Ocean Model (MOM); the Community Earth System Model (CESM); and the NASA ModelE climate model and GEOS-5 atmospheric general circulation model.

  3. The Earth System Prediction Suite: Toward a Coordinated U.S. Modeling Capability

    NASA Technical Reports Server (NTRS)

    Theurich, Gerhard; DeLuca, C.; Campbell, T.; Liu, F.; Saint, K.; Vertenstein, M.; Chen, J.; Oehmke, R.; Doyle, J.; Whitcomb, T.; hide

    2016-01-01

    The Earth System Prediction Suite (ESPS) is a collection of flagship U.S. weather and climate models and model components that are being instrumented to conform to interoperability conventions, documented to follow metadata standards, and made available either under open source terms or to credentialed users.The ESPS represents a culmination of efforts to create a common Earth system model architecture, and the advent of increasingly coordinated model development activities in the U.S. ESPS component interfaces are based on the Earth System Modeling Framework (ESMF), community-developed software for building and coupling models, and the National Unified Operational Prediction Capability (NUOPC) Layer, a set of ESMF-based component templates and interoperability conventions. This shared infrastructure simplifies the process of model coupling by guaranteeing that components conform to a set of technical and semantic behaviors. The ESPS encourages distributed, multi-agency development of coupled modeling systems, controlled experimentation and testing, and exploration of novel model configurations, such as those motivated by research involving managed and interactive ensembles. ESPS codes include the Navy Global Environmental Model (NavGEM), HYbrid Coordinate Ocean Model (HYCOM), and Coupled Ocean Atmosphere Mesoscale Prediction System (COAMPS); the NOAA Environmental Modeling System (NEMS) and the Modular Ocean Model (MOM); the Community Earth System Model (CESM); and the NASA ModelE climate model and GEOS-5 atmospheric general circulation model.

  4. Chemistry and physics of a single atomic layer: strategies and challenges for functionalization of graphene and graphene-based materials.

    PubMed

    Yan, Liang; Zheng, Yue Bing; Zhao, Feng; Li, Shoujian; Gao, Xingfa; Xu, Bingqian; Weiss, Paul S; Zhao, Yuliang

    2012-01-07

    Graphene has attracted great interest for its superior physical, chemical, mechanical, and electrical properties that enable a wide range of applications from electronics to nanoelectromechanical systems. Functionalization is among the significant vectors that drive graphene towards technological applications. While the physical properties of graphene have been at the center of attention, we still lack the knowledge framework for targeted graphene functionalization. In this critical review, we describe some of the important chemical and physical processes for graphene functionalization. We also identify six major challenges in graphene research and give perspectives and practical strategies for both fundamental studies and applications of graphene (315 references). This journal is © The Royal Society of Chemistry 2012

  5. Strain engineering of the silicon-vacancy center in diamond

    NASA Astrophysics Data System (ADS)

    Meesala, Srujan; Sohn, Young-Ik; Pingault, Benjamin; Shao, Linbo; Atikian, Haig A.; Holzgrafe, Jeffrey; Gündoǧan, Mustafa; Stavrakas, Camille; Sipahigil, Alp; Chia, Cleaven; Evans, Ruffin; Burek, Michael J.; Zhang, Mian; Wu, Lue; Pacheco, Jose L.; Abraham, John; Bielejec, Edward; Lukin, Mikhail D.; Atatüre, Mete; Lončar, Marko

    2018-05-01

    We control the electronic structure of the silicon-vacancy (SiV) color-center in diamond by changing its static strain environment with a nano-electro-mechanical system. This allows deterministic and local tuning of SiV optical and spin transition frequencies over a wide range, an essential step towards multiqubit networks. In the process, we infer the strain Hamiltonian of the SiV revealing large strain susceptibilities of order 1 PHz/strain for the electronic orbital states. We identify regimes where the spin-orbit interaction results in a large strain susceptibility of order 100 THz/strain for spin transitions, and propose an experiment where the SiV spin is strongly coupled to a nanomechanical resonator.

  6. Coal Transportation Rate Sensitivity Analysis

    EIA Publications

    2005-01-01

    On December 21, 2004, the Surface Transportation Board (STB) requested that the Energy Information Administration (EIA) analyze the impact of changes in coal transportation rates on projected levels of electric power sector energy use and emissions. Specifically, the STB requested an analysis of changes in national and regional coal consumption and emissions resulting from adjustments in railroad transportation rates for Wyoming's Powder River Basin (PRB) coal using the National Energy Modeling System (NEMS). However, because NEMS operates at a relatively aggregate regional level and does not represent the costs of transporting coal over specific rail lines, this analysis reports on the impacts of interregional changes in transportation rates from those used in the Annual Energy Outlook 2005 (AEO2005) reference case.

  7. Liquid Fuels Market Module - NEMS Documentation

    EIA Publications

    2017-01-01

    Defines the objectives of the Liquid Fuels Market Model (LFMM), describes its basic approach, and provides detail on how it works. This report is intended as a reference document for model analysts, users, and the public. This edition of the LFMM reflects changes made to the module over the past two years for the Annual Energy Outlook 2016.

  8. Radiation Effects in M and NEMS

    DTIC Science & Technology

    2016-03-31

    10.1117/12.876968 casing mobile core AFM tip Pt wire x δ a Figure 5. Proposed approach to combine single crystal silicon MEMS (Sandia) fab capabilities and form supporting structure for 2D materials (VU). 198

  9. N-ethylmaleimide activates a Cl(-)-independent component of K(+) flux in mouse erythrocytes.

    PubMed

    Shmukler, Boris E; Hsu, Ann; Alves, Jessica; Trudel, Marie; Rust, Marco B; Hubner, Christian A; Rivera, Alicia; Alper, Seth L

    2013-06-01

    The K-Cl cotransporters (KCCs) of mouse erythrocytes exhibit higher basal activity than those of human erythrocytes, but are similarly activated by cell swelling, by hypertonic urea, and by staurosporine. However, the dramatic stimulation of human erythroid KCCs by N-ethylmaleimide (NEM) is obscured in mouse erythrocytes by a prominent NEM-stimulated K(+) efflux that lacks Cl(-)-dependence. The NEM-sensitivity of Cl(-)-independent K(+) efflux of mouse erythrocytes is lower than that of KCC. The genetically engineered absence of the K-Cl cotransporters KCC3 and KCC1 from mouse erythrocytes does not modify Cl(-)-independent K(+) efflux. Mouse erythrocytes genetically devoid of the Gardos channel KCNN4 show increased NEM-sensitivity of both Cl(-)-independent K(+) efflux and K-Cl cotransport. The increased NEM-sensitivity and stimulation magnitude of Cl(-)-independent K(+) efflux in mouse erythrocytes expressing transgenic hypersickling human hemoglobin SAD (HbSAD) are independent of the presence of KCC3 and KCC1, but absence of KCNN4 reduces the stimulatory effect of HbSAD. NEM-stimulated Cl(-)-independent K(+) efflux of mouse red cells is insensitive to ouabain and bumetanide, but partially inhibited by chloroquine, barium, and amiloride. The NEM-stimulated activity is modestly reduced at pH6.0 but not significantly altered at pH8.0, and is abolished at 0°C. Although the molecular identity of this little-studied K(+) efflux pathway of mouse erythrocytes remains unknown, its potential role in the pathophysiology of sickle red cell dehydration will be important for the extrapolation of studies in mouse models of sickle cell disease to our understanding of humans with sickle cell anemia. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. SPATIAL AND TEMPORAL VARIABILITY AND DRIVERS OF NET ECOSYSTEM METABOLISM IN WESTERN GULF OF MEXICO ESTUARIES

    EPA Science Inventory

    Net ecosystem metabolism (NEM) is becoming a commonly used ecological indicator of estuarine ecosystem metabolic rates. Estuarine ecosystem processes are spatially and temporally variable, but the corresponding variability in NEM has not been properly assessed. Spatial and temp...

  11. Engineering challenges of BioNEMS: the integration of microfluidics, micro- and nanodevices, models and external control for systems biology.

    PubMed

    Wikswo, J P; Prokop, A; Baudenbacher, F; Cliffel, D; Csukas, B; Velkovsky, M

    2006-08-01

    Systems biology, i.e. quantitative, postgenomic, postproteomic, dynamic, multiscale physiology, addresses in an integrative, quantitative manner the shockwave of genetic and proteomic information using computer models that may eventually have 10(6) dynamic variables with non-linear interactions. Historically, single biological measurements are made over minutes, suggesting the challenge of specifying 10(6) model parameters. Except for fluorescence and micro-electrode recordings, most cellular measurements have inadequate bandwidth to discern the time course of critical intracellular biochemical events. Micro-array expression profiles of thousands of genes cannot determine quantitative dynamic cellular signalling and metabolic variables. Major gaps must be bridged between the computational vision and experimental reality. The analysis of cellular signalling dynamics and control requires, first, micro- and nano-instruments that measure simultaneously multiple extracellular and intracellular variables with sufficient bandwidth; secondly, the ability to open existing internal control and signalling loops; thirdly, external BioMEMS micro-actuators that provide high bandwidth feedback and externally addressable intracellular nano-actuators; and, fourthly, real-time, closed-loop, single-cell control algorithms. The unravelling of the nested and coupled nature of cellular control loops requires simultaneous recording of multiple single-cell signatures. Externally controlled nano-actuators, needed to effect changes in the biochemical, mechanical and electrical environment both outside and inside the cell, will provide a major impetus for nanoscience.

  12. Impulsivity and negative emotionality associated with substance use problems and Cluster B personality in college students.

    PubMed

    James, Lisa M; Taylor, Jeanette

    2007-04-01

    The co-occurrence of personality disorders (PDs) and substance use disorders (SUDs) can be partially attributed to shared underlying personality traits. This study examined the role of negative emotionality (NEM) and impulsivity in 617 university students with self-reported substance use problems and Cluster B PD symptoms. Results indicated that NEM was significantly associated with drug and alcohol use problems, antisocial PD, borderline PD, and narcissistic PD. Impulsivity was significantly associated with drug use problems, antisocial PD, and histrionic PD. Only NEM mediated the relationship between alcohol use problems and symptoms of each of the Cluster B PDs while impulsivity mediated only the relationship between drug use problems and histrionic PD. These results suggest that NEM may be more relevant than impulsivity to our understanding of the co-occurrence between substance use problems and Cluster B PD features.

  13. Variability of terrigenous input to the Bay of Bengal for the last 80 kyr: Implications on the Indian monsoon variability

    NASA Astrophysics Data System (ADS)

    Panmei, Champoungam; Naidu, Pothuri Divakar; Naik, Sushant Suresh

    2018-06-01

    Oceanographic processes in the Bay of Bengal (BoB) are strongly impacted by south-westerly and north-easterly winds of the Indian monsoon system during the summer and winter respectively. Variations in calcium carbonate (CaCO3) content and magnetic susceptibility (MS), along with Ba, Ti, and Al, were reconstructed for the past 80 kyr using a sediment core (MD 161/28) from the northern BoB in order to understand the changes in calcium carbonate deposition and MS signals associated with the Indian monsoon system. Our records infer monsoon-induced dilution through river discharges from different sediment provenance to be the main controlling factor of the CaCO3 variations at the core location. Generally lower CaCO3 content during stronger-southwest monsoon (SWM) interglacial periods (Marine Isotope Stage (MIS) 5a & 1, except 3) and higher CaCO3 content during weaker-SWM glacial periods (MIS 4 & 2) were documented. High MS correspond to MIS 4 & 2 of weakened SWM and strengthened northeast monsoon (NEM) periods caused due to enhanced sediment supply from the Peninsular Indian regions, whereas lower MS values correspond to MIS 5, 3 & 1 of strengthened SWM and weakened NEM derived through Ganges-Brahmaputra from the Himalaya Region. Thus, our records infer coupling of major rivers' discharges to the BoB with the SWM and NEM strengths, which has implications on the linkage with other climatic variations such as East Asian monsoon and Northern Hemisphere climate.

  14. The Earth System Prediction Suite: Toward a Coordinated U.S. Modeling Capability

    DOE PAGES

    Theurich, Gerhard; DeLuca, C.; Campbell, T.; ...

    2016-08-22

    The Earth System Prediction Suite (ESPS) is a collection of flagship U.S. weather and climate models and model components that are being instrumented to conform to interoperability conventions, documented to follow metadata standards, and made available either under open-source terms or to credentialed users. Furthermore, the ESPS represents a culmination of efforts to create a common Earth system model architecture, and the advent of increasingly coordinated model development activities in the United States. ESPS component interfaces are based on the Earth System Modeling Framework (ESMF), community-developed software for building and coupling models, and the National Unified Operational Prediction Capability (NUOPC)more » Layer, a set of ESMF-based component templates and interoperability conventions. Our shared infrastructure simplifies the process of model coupling by guaranteeing that components conform to a set of technical and semantic behaviors. The ESPS encourages distributed, multiagency development of coupled modeling systems; controlled experimentation and testing; and exploration of novel model configurations, such as those motivated by research involving managed and interactive ensembles. ESPS codes include the Navy Global Environmental Model (NAVGEM), the Hybrid Coordinate Ocean Model (HYCOM), and the Coupled Ocean–Atmosphere Mesoscale Prediction System (COAMPS); the NOAA Environmental Modeling System (NEMS) and the Modular Ocean Model (MOM); the Community Earth System Model (CESM); and the NASA ModelE climate model and the Goddard Earth Observing System Model, version 5 (GEOS-5), atmospheric general circulation model.« less

  15. The Earth System Prediction Suite: Toward a Coordinated U.S. Modeling Capability

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Theurich, Gerhard; DeLuca, C.; Campbell, T.

    The Earth System Prediction Suite (ESPS) is a collection of flagship U.S. weather and climate models and model components that are being instrumented to conform to interoperability conventions, documented to follow metadata standards, and made available either under open-source terms or to credentialed users. Furthermore, the ESPS represents a culmination of efforts to create a common Earth system model architecture, and the advent of increasingly coordinated model development activities in the United States. ESPS component interfaces are based on the Earth System Modeling Framework (ESMF), community-developed software for building and coupling models, and the National Unified Operational Prediction Capability (NUOPC)more » Layer, a set of ESMF-based component templates and interoperability conventions. Our shared infrastructure simplifies the process of model coupling by guaranteeing that components conform to a set of technical and semantic behaviors. The ESPS encourages distributed, multiagency development of coupled modeling systems; controlled experimentation and testing; and exploration of novel model configurations, such as those motivated by research involving managed and interactive ensembles. ESPS codes include the Navy Global Environmental Model (NAVGEM), the Hybrid Coordinate Ocean Model (HYCOM), and the Coupled Ocean–Atmosphere Mesoscale Prediction System (COAMPS); the NOAA Environmental Modeling System (NEMS) and the Modular Ocean Model (MOM); the Community Earth System Model (CESM); and the NASA ModelE climate model and the Goddard Earth Observing System Model, version 5 (GEOS-5), atmospheric general circulation model.« less

  16. Organic carbon balance and net ecosystem metabolism in Chesapeake Bay

    USGS Publications Warehouse

    Kemp, W.M.; Smith, E.M.; Marvin-DiPasquale, M.; Boynton, W.R.

    1997-01-01

    The major fluxes of organic carbon associated with physical transport and biological metabolism were compiled, analyzed and compared for the mainstem portion of Chesapeake Bay (USA). In addition, 5 independent methods were used to calculate the annual mean net ecosystem metabolism (NEM = production - respiration) for the integrated Bay. These methods, which employed biogeochemical models, nutrient mass-balances anti summation of individual organic carbon fluxes, yielded remarkably similar estimates, with a mean NEM of +50 g C m-2 yr-1 (?? SE = 751, which is approximately 8% of the estimated annual average gross primary production. These calculations suggest a strong cross-sectional pattern in NEM throughout the Bay, wherein net heterotrophic metabolism prevails in the pelagic zones of the main channel, while net autotrophy occurs in the littoral zones which flank the deeper central area. For computational purposes, the estuary was separated into 3 regions along the land-sea gradient: (1) the oligohaline Upper Bay (11% of total area); (2) the mesohaline Mid Bay (36% of area); and (3) the polyhaline Lower Bay (53% of area). A distinct regional trend in NEM was observed along this salinity gradient, with net here(atrophy (NEM = 87 g C m-2 yr-1) in the Upper Bay, balanced metabolism in the Mid Bay and net autotrophy (NEM = +92 g C m-2 yr-1) in the Lower Bay. As a consequence of overall net autotrophy, the ratio of dissolved inorganic nitrogen (DIN) to total organic nitrogen (TON) changed from DIN:TON = 5.1 for riverine inputs to DIN:TON = 0.04 for water exported to the ocean. A striking feature of this organic C mass-balance was the relative dominance of biologically mediated metabolic fluxes compared to physical transport fluxes. The overall ratio of physical TOC inputs (1) to biotic primary production (P) was 0.08 for the whole estuary, but varied dramatically from 2.3 in the Upper Bay to 0.03 in the Mid and Lower Bay regions. Similarly, ecosystem respiration was

  17. National Centers for Environmental Prediction

    Science.gov Websites

    Modeling Mesoscale Modeling Marine Modeling and Analysis Teams Climate Data Assimilation Ensembles and Post streamline the interaction of analysis, forecast, and post-processing systems within NCEP. The NEMS Force, and will eventually provide support to the community through the Developmental Test Center (DTC

  18. Novel autosomal dominant TNNT1 mutation causing nemaline myopathy.

    PubMed

    Konersman, Chamindra G; Freyermuth, Fernande; Winder, Thomas L; Lawlor, Michael W; Lagier-Tourenne, Clotilde; Patel, Shailendra B

    2017-11-01

    Nemaline myopathy (NEM) is one of the three major forms of congenital myopathy and is characterized by diffuse muscle weakness, hypotonia, respiratory insufficiency, and the presence of nemaline rod structures on muscle biopsy. Mutations in troponin T1 (TNNT1) is 1 of 10 genes known to cause NEM. To date, only homozygous nonsense mutations or compound heterozygous truncating or internal deletion mutations in TNNT1 gene have been identified in NEM. This extended family is of historical importance as some members were reported in the 1960s as initial evidence that NEM is a hereditary disorder. Proband and extended family underwent Sanger sequencing for TNNT1. We performed RT-PCR and immunoblot on muscle to assess TNNT1 RNA expression and protein levels in proband and father. We report a novel heterozygous missense mutation of TNNT1 c.311A>T (p.E104V) that segregated in an autosomal dominant fashion in a large family residing in the United States. Extensive sequencing of the other known genes for NEM failed to identify any other mutant alleles. Muscle biopsies revealed a characteristic pattern of nemaline rods and severe myofiber hypotrophy that was almost entirely restricted to the type 1 fiber population. This novel mutation alters a residue that is highly conserved among vertebrates. This report highlights not only a family with autosomal dominant inheritance of NEM, but that this novel mutation likely acts via a dominant negative mechanism. © 2017 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals, Inc.

  19. Review of terahertz semiconductor sources

    NASA Astrophysics Data System (ADS)

    Wei, Feng

    2012-03-01

    Terahertz (THz) technology can be used in information science, biology, medicine, astronomy, and environmental science. THz sources are the key devices in THz applications. The author gives a brief review of THz semiconductor sources, such as GaAs1-xNx Gunn-like diodes, quantum wells (QWs) negative-effective-mass (NEM) THz oscillators, and the THz quantum cascade lasers (QCLs). THz current self-oscillation in doped GaAs1-xNx diodes driven by a DC electric field was investigated. The current self-oscillation is associated with the negative differential velocity effect in the highly nonparabolic conduction band of this unique material system. The current self-oscillations and spatiotemporal current patterns in QW NEM p+pp+ diodes was studied by considering scattering contributions from impurities, acoustic phonons, and optic phonons. It is indicated that both the applied bias and the doping concentration strongly influence the patterns and self-oscillating frequencies. The NEM p+pp+ diode may be used as an electrically tunable THz source. Meanwhile, by using the Monte Carlo method, the device parameters of resonant-phonon THz QCLs were optimized. The results show that the calculated gain is more sensitive to the injection barrier width, the doping concentration, and the phonon extraction level separation, which is consistent with the experiments.

  20. Advanced Concepts in Josephson Junction Reflection Amplifiers

    NASA Astrophysics Data System (ADS)

    Lähteenmäki, Pasi; Vesterinen, Visa; Hassel, Juha; Paraoanu, G. S.; Seppä, Heikki; Hakonen, Pertti

    2014-06-01

    Low-noise amplification at microwave frequencies has become increasingly important for the research related to superconducting qubits and nanoelectromechanical systems. The fundamental limit of added noise by a phase-preserving amplifier is the standard quantum limit, often expressed as noise temperature . Towards the goal of the quantum limit, we have developed an amplifier based on intrinsic negative resistance of a selectively damped Josephson junction. Here we present measurement results on previously proposed wide-band microwave amplification and discuss the challenges for improvements on the existing designs. We have also studied flux-pumped metamaterial-based parametric amplifiers, whose operating frequency can be widely tuned by external DC-flux, and demonstrate operation at pumping, in contrast to the typical metamaterial amplifiers pumped via signal lines at.

  1. Molecular switches and motors on surfaces.

    PubMed

    Pathem, Bala Krishna; Claridge, Shelley A; Zheng, Yue Bing; Weiss, Paul S

    2013-01-01

    Molecular switches and motors respond structurally, electronically, optically, and/or mechanically to external stimuli, testing and potentially enabling extreme miniaturization of optoelectronic devices, nanoelectromechanical systems, and medical devices. The assembly of motors and switches on surfaces makes it possible both to measure the properties of individual molecules as they relate to their environment and to couple function between assembled molecules. In this review, we discuss recent progress in assembling molecular switches and motors on surfaces, measuring static and dynamic structures, understanding switching mechanisms, and constructing functional molecular materials and devices. As demonstrative examples, we choose a representative molecule from three commonly studied classes including molecular switches, photochromic molecules, and mechanically interlocked molecules. We conclude by offering perspectives on the future of molecular switches and motors on surfaces.

  2. Assessing the Consumer Food Environment in Restaurants by Neighbourhood Distress Level across Saskatoon, Saskatchewan.

    PubMed

    Wang, Jin; Engler-Stringer, Rachel; Muhajarine, Nazeem

    2016-03-01

    To assess the consumer food environment in restaurants in Saskatoon, using the Nutrition Environment Measures Survey for Restaurants (NEMS-R), to examine differences by neighbourhood distress level and to reflect on the need for further refinement of the assessment of restaurant consumer food environments. Neighbourhoods were classified as low, middle, or high distress level based on the socioeconomic indicators (income, employment, and education) in the Material Deprivation Index. Differences in restaurant consumer food environments, indicated by mean NEMS-R total and sub-scores, were examined by various restaurant categories and by varying neighbourhood distress levels. Chain coffee shops and pita and sandwich restaurants had higher NEMS-R totals and "Healthy Entrées" sub-scores; however, burger and chicken restaurants and pizza restaurants had more barriers to healthful eating. Although restaurants in lower distress level neighbourhoods generally rated healthier (higher NEMS-R scores), only a few measures (such as "Facilitators" and "Barriers") significantly differed by neighbourhood distress level. The findings highlight the importance of developing interventions to improve restaurant consumer food environments, especially in neighbourhoods with higher distress levels. The results suggest that reliable measures of the consumer food environment could be developed beginning with what can be measured by NEMS-R.

  3. 78 FR 52426 - Retail Commodity Transactions Under Commodity Exchange Act

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-23

    ... enacted to reduce risk, increase transparency, and promote market integrity within the financial system by... typical commercial practice in cash or spot markets for the commodity involved.\\11\\ \\10\\ 7 U.S.C. 2(c)(2..., LLP (GBT), and Rothgerber Johnson & Lyons LLP (RJL). \\17\\ National Energy Markets Association (NEM...

  4. Assumptions to the Annual Energy Outlook

    EIA Publications

    2017-01-01

    This report presents the major assumptions of the National Energy Modeling System (NEMS) used to generate the projections in the Annual Energy Outlook, including general features of the model structure, assumptions concerning energy markets, and the key input data and parameters that are the most significant in formulating the model results.

  5. Intracellular acidification reduces l-arginine transport via system y+L but not via system y+/CATs and nitric oxide synthase activity in human umbilical vein endothelial cells.

    PubMed

    Ramírez, Marco A; Morales, Jorge; Cornejo, Marcelo; Blanco, Elias H; Mancilla-Sierpe, Edgardo; Toledo, Fernando; Beltrán, Ana R; Sobrevia, Luis

    2018-04-01

    l-Arginine is taken up via the cationic amino acid transporters (system y + /CATs) and system y + L in human umbilical vein endothelial cells (HUVECs). l-Arginine is the substrate for endothelial NO synthase (eNOS) which is activated by intracellular alkalization, but nothing is known regarding modulation of system y + /CATs and system y + L activity, and eNOS activity by the pHi in HUVECs. We studied whether an acidic pHi modulates l-arginine transport and eNOS activity in HUVECs. Cells loaded with a pH-sensitive probe were subjected to 0.1-20 mmol/L NH 4 Cl pulse assay to generate pHi 7.13-6.55. Before pHi started to recover, l-arginine transport (0-20 or 0-1000 μmol/L, 10 s, 37 °C) in the absence or presence of 200 μmol/L N-ethylmaleimide (NEM) (system y + /CATs inhibitor) or 2 mmol/L l-leucine (systemy + L substrate) was measured. Protein abundance for eNOS and serine 1177 or threonine 495 phosphorylated eNOS was determined. The results show that intracellular acidification reduced system y + L but not system y + /CATs mediated l-arginine maximal transport capacity due to reduced maximal velocity. Acidic pHi reduced NO synthesis and eNOS serine 1177 phosphorylation. Thus, system y + L activity is downregulated by an acidic pHi, a phenomenon that may result in reduced NO synthesis in HUVECs. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Determination of effective mechanical properties of a double-layer beam by means of a nano-electromechanical transducer

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hocke, Fredrik; Pernpeintner, Matthias; Gross, Rudolf, E-mail: rudolf.gross@wmi.badw.de

    We investigate the mechanical properties of a doubly clamped, double-layer nanobeam embedded into an electromechanical system. The nanobeam consists of a highly pre-stressed silicon nitride and a superconducting niobium layer. By measuring the mechanical displacement spectral density both in the linear and the nonlinear Duffing regime, we determine the pre-stress and the effective Young's modulus of the nanobeam. An analytical double-layer model quantitatively corroborates the measured values. This suggests that this model can be used to design mechanical multilayer systems for electro- and optomechanical devices, including materials controllable by external parameters such as piezoelectric, magnetostrictive, or in more general multiferroicmore » materials.« less

  7. Reduced-Item Food Audits Based on the Nutrition Environment Measures Surveys.

    PubMed

    Partington, Susan N; Menzies, Tim J; Colburn, Trina A; Saelens, Brian E; Glanz, Karen

    2015-10-01

    The community food environment may contribute to obesity by influencing food choice. Store and restaurant audits are increasingly common methods for assessing food environments, but are time consuming and costly. A valid, reliable brief measurement tool is needed. The purpose of this study was to develop and validate reduced-item food environment audit tools for stores and restaurants. Nutrition Environment Measures Surveys for stores (NEMS-S) and restaurants (NEMS-R) were completed in 820 stores and 1,795 restaurants in West Virginia, San Diego, and Seattle. Data mining techniques (correlation-based feature selection and linear regression) were used to identify survey items highly correlated to total survey scores and produce reduced-item audit tools that were subsequently validated against full NEMS surveys. Regression coefficients were used as weights that were applied to reduced-item tool items to generate comparable scores to full NEMS surveys. Data were collected and analyzed in 2008-2013. The reduced-item tools included eight items for grocery, ten for convenience, seven for variety, and five for other stores; and 16 items for sit-down, 14 for fast casual, 19 for fast food, and 13 for specialty restaurants-10% of the full NEMS-S and 25% of the full NEMS-R. There were no significant differences in median scores for varying types of retail food outlets when compared to the full survey scores. Median in-store audit time was reduced 25%-50%. Reduced-item audit tools can reduce the burden and complexity of large-scale or repeated assessments of the retail food environment without compromising measurement quality. Copyright © 2015 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  8. Assessment of a University Campus Food Environment, California, 2015.

    PubMed

    Tseng, Marilyn; DeGreef, Kelsey; Fishler, Madison; Gipson, Rachel; Koyano, Kelly; Neill, Dawn B

    2016-02-04

    University campuses offer an opportunity to study the extent to which modifying the food environment influences eating, but in-depth characterizations of campus food environments are needed to identify potential targets for intervention. The objective of this project was to describe the availability, accessibility, and quality of healthful food choices in dining venues and food stores at or near a public, 4-year university in California. Trained assessors used the Nutrition Environment Measures Survey for campus dining (NEMS-CD) to evaluate all 18 campus dining venues, and NEMS for stores (NEMS-S) to evaluate 2 on-campus and 37 off-campus food stores. We calculated prevalence of healthful and unhealthful constructs (eg, availability of selected food items, presence of signage encouraging healthful eating, pricing options that encourage healthful eating), based on the NEMS and compared scores across different types of venues. NEMS-CD scores ranged from 4 to 47 (mean [SD], 26.0 [14.4]) out of a possible maximum score of 97; 12% of entrées and 36% of main dish salads served in these venues were classified as healthful. NEMS-S score for the 2 on-campus food stores (24 for both) was intermediate between off-campus convenience stores (mean [SD], 12.0 [5.3]) and grocery/supermarket stores (mean [SD], 31.1 [10.0]), with a possible maximum score of 54. Standardized environmental evaluation provides insights into both positive and negative aspects of campus community food venues. Environmental assessment identifies potential targets for modification and baseline data for designing and implementing action-oriented research aimed at improving the campus food environment's support of healthful food choices for college students.

  9. National Centers for Environmental Prediction

    Science.gov Websites

    Operational Forecast Graphics Experimental Forecast Graphics Verification and Diagnostics Model Configuration consists of the following components: - The NOAA Environmental Modeling System (NEMS) version of the Non updates for the 12 km parent domain and the 3 km CONUS/Alaska nests. The non-cycled nests (Hawaii, Puerto

  10. Regulation of lipid droplet and membrane biogenesis by the acidic tail of the phosphatidate phosphatase Pah1p

    PubMed Central

    Karanasios, Eleftherios; Barbosa, Antonio Daniel; Sembongi, Hiroshi; Mari, Muriel; Han, Gil-Soo; Reggiori, Fulvio; Carman, George M.; Siniossoglou, Symeon

    2013-01-01

    Lipins are evolutionarily conserved phosphatidate phosphatases that perform key functions in phospholipid, triglyceride, and membrane biogenesis. Translocation of lipins on membranes requires their dephosphorylation by the Nem1p-Spo7p transmembrane phosphatase complex through a poorly understood mechanism. Here we identify the carboxy-terminal acidic tail of the yeast lipin Pah1p as an important regulator of this step. Deletion or mutations of the tail disrupt binding of Pah1p to the Nem1p-Spo7p complex and Pah1p membrane translocation. Overexpression of Nem1p-Spo7p drives the recruitment of Pah1p in the vicinity of lipid droplets in an acidic tail–dependent manner and induces lipid droplet biogenesis. Genetic analysis shows that the acidic tail is essential for the Nem1p-Spo7p–dependent activation of Pah1p but not for the function of Pah1p itself once it is dephosphorylated. Loss of the tail disrupts nuclear structure, INO1 gene expression, and triglyceride synthesis. Similar acidic sequences are present in the carboxy-terminal ends of all yeast lipin orthologues. We propose that acidic tail–dependent binding and dephosphorylation of Pah1p by the Nem1p-Spo7p complex is an important determinant of its function in lipid and membrane biogenesis. PMID:23657815

  11. Pulsed electric field (PEF)-induced aggregation between lysozyme, ovalbumin and ovotransferrin in multi-protein system.

    PubMed

    Wu, Li; Zhao, Wei; Yang, Ruijin; Yan, Wenxu

    2015-05-15

    The aggregation of multi-proteins is of great interest in food processing and a good understanding of the formation of aggregates during PEF processing is needed for the application of the process to pasteurize protein-based foods. The aggregates formation of a multi-protein system (containing ovalbumin, ovotransferrin and lysozyme) was studied through turbidity, size exclusion chromatography and SDS-PAGE patterns for interaction studies and binding forces. Results from size exclusion chromatography indicated that there was no soluble aggregates formed during PEF processing. The existence of lysozyme was important to form insoluble aggregates in the chosen ovalbumin solution. The results of SDS-PAGE patterns indicated that lysozyme was prone to precipitate, and was relatively the higher component of aggregates. Citric acid could be effective in inhibiting lysozyme from interacting with other proteins during PEF processing. Blocking the free sulphydryl by N-ethylmaleimide (NEM) did not affect aggregation inhibition. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Preliminary Assessment of the Nutrient Film Technique for Wastewater Treatment

    DTIC Science & Technology

    1982-03-01

    umre) Hydroponics Thin films Wastes (Sanitary engineering) \\Waslewater \\I MArWIASSACr a m evemww sb N nem y., d idenif, by block nm,6...) An experiment...best described attach themselves. as a modified hydroponic system in which a thin film of nutrient solution flows through the root mat of Purpose plants...of an experiment conducted at CRREL to de- tween an NFT system and a hydroponic plant system termine the feasibility of using the nutrient film tech

  13. Nanostructured surfaces using thermal nanoimprint lithography: Applications in thin membrane technology, piezoelectric energy harvesting and tactile pressure sensing

    NASA Astrophysics Data System (ADS)

    Nabar, Bhargav Pradip

    Nanoimprint lithography (NIL) is emerging as a viable contender for fabrication of large-scale arrays of 5-500 nm features. The work presented in this dissertation aims to leverage the advantages of NIL for realization of novel Nano Electro Mechanical Systems (NEMS). The first application is a nanoporous membrane blood oxygenator system. A fabrication process for realization of thin nanoporous membranes using thermal nanoimprint lithography is presented. Suspended silicon nitride membranes were fabricated by Low-Pressure Chemical Vapor Deposition (LPCVD) in conjunction with a potassium hydroxide-based bulk micromachining process. Nanoscale features were imprinted into a commercially available thermoplastic polymer resist using a pre-fabricated silicon mold. The pattern was reversed and transferred to a thin aluminum oxide layer by means of a novel two stage lift-off technique. The patterned aluminum oxide was used as an etch mask in a CHF3/He based reactive ion etch process to transfer the pattern to silicon nitride. Highly directional etch profiles with near vertical sidewalls and excellent Si3N4/Al2O3 etch selectivity was observed. One-micrometer-thick porous membranes with varying dimensions of 250x250 microm2 to 450x450 microm 2 and pore diameter of 400 nm have been engineered and evaluated. Results indicate that the membranes have consistent nanopore dimensions and precisely defined porosity, which makes them ideal as gas exchange interfaces in blood oxygenation systems as well as other applications such as dialysis. Additionally, bulk -- micromachined microfluidic channels have been developed for uniform, laminar blood flow with minimal cell trauma. NIL has been used for ordered growth of crystalline nanostructures for sensing and energy harvesting. Highly ordered arrays of crystalline ZnO nanorods have been fabricated using a polymer template patterned by thermal nanoimprint lithography, in conjunction with a low temperature hydrothermal growth process. Zinc

  14. Assessment of a University Campus Food Environment, California, 2015

    PubMed Central

    DeGreef, Kelsey; Fishler, Madison; Gipson, Rachel; Koyano, Kelly; Neill, Dawn B.

    2016-01-01

    Introduction University campuses offer an opportunity to study the extent to which modifying the food environment influences eating, but in-depth characterizations of campus food environments are needed to identify potential targets for intervention. The objective of this project was to describe the availability, accessibility, and quality of healthful food choices in dining venues and food stores at or near a public, 4-year university in California. Methods Trained assessors used the Nutrition Environment Measures Survey for campus dining (NEMS-CD) to evaluate all 18 campus dining venues, and NEMS for stores (NEMS-S) to evaluate 2 on-campus and 37 off-campus food stores. We calculated prevalence of healthful and unhealthful constructs (eg, availability of selected food items, presence of signage encouraging healthful eating, pricing options that encourage healthful eating), based on the NEMS and compared scores across different types of venues. Results NEMS-CD scores ranged from 4 to 47 (mean [SD], 26.0 [14.4]) out of a possible maximum score of 97; 12% of entrées and 36% of main dish salads served in these venues were classified as healthful. NEMS-S score for the 2 on-campus food stores (24 for both) was intermediate between off-campus convenience stores (mean [SD], 12.0 [5.3]) and grocery/supermarket stores (mean [SD], 31.1 [10.0]), with a possible maximum score of 54. Conclusion Standardized environmental evaluation provides insights into both positive and negative aspects of campus community food venues. Environmental assessment identifies potential targets for modification and baseline data for designing and implementing action-oriented research aimed at improving the campus food environment’s support of healthful food choices for college students. PMID:26851337

  15. High accuracy of the nine equivalents of nursing manpower use score assessed by critical care nurses.

    PubMed

    Perren, Andreas; Previsdomini, Marco; Perren, Ilaria; Merlani, Paolo

    2012-04-05

    The nine equivalents of nursing manpower use score (NEMS) is frequently used to quantify, evaluate and allocate nursing workload at intensive care unit level. In Switzerland it has also become a key component in defining the degree of ICU hospital reimbursement. The accuracy of nurse registered NEMS scores in real life was assessed and error-prone variables were identified. In this retrospective multicentre audit three reviewers (1 nurse, 2 intensivists) independently reassessed a total of 529 NEMS scores. Correlation and agreement of the sum-scores and of the different variables among reviewers, as well as between nurses and the reviewers' reference value, were assessed (ICC, % agreement and kappa). Bland & Altman (reference value - nurses) of sum-scores and regression of the difference were determined and a logistic regression model identifying risk factors for erroneous assessments was calculated. Agreement for sum-scores among reviewers was almost perfect (mean ICC = 0.99 / significant correlation p <0.0001). The nurse registered NEMS score (mean ± SD) was 24.8 ± 8.6 points versus 24.0 ± 8.6 points (p <0.13 for difference) of the reference value, with a slightly lower ICC (0.83). The lowest agreement was found in intravenous medication (0.85). Bland & Altman was 0.84 ± 10, with a significant regression between the difference and the reference value, indicating overall an overestimation of lower scores (≤29 points) and underestimation of higher scores. Accuracy of scores or variables was not associated with nurses' characteristics. In real life, nurse registered NEMS scores are highly accurate. Lower (≤29 points) NEMS sum-scores are overestimated and higher underestimated. Accuracy of scores or variables was not associated with nurses' characteristics.

  16. [Congenital malformations in the offspring of epileptic mothers with and without anticonvulsant treatment].

    PubMed

    Arteaga-Vázquez, Jazmín; Luna-Muñoz, Leonora; Mutchinick, Osvaldo M

    2012-01-01

    To determine the prevalence at birth and type of congenital malformations (CM) in newborns of epileptic mothers (NEM) treated and not treated with anticonvulsants, the correlation anticonvulsant/CM and other developmental disorders. Multicenter case-control study, in 166 live births NEM diagnosed in 21 501 newborns with CM and respective controls from the Registro y Vigilancia Epidemiológica de Malformaciones Congénitas (RYVEMCE). The frequency of CM in NEM treated with anticonvulsants was higher (48.3%) than in NEM of untreated mothers (28.3%), (OR= 2.37 IC95% 1.08-5.40), p=0.03. CMs most frequently found were: spina bifida, limb reduction defects, cleft lip palate, microcephaly, anotia/microtia, hypospadias, polydactyly, cleft palate, anophthalmia/ microphthalmia and omphalocele. No differences among monotherapy and polytherapy were observed. Diphenyl-hydantoin, carbamazepine and valproic acid were the most frequently anticonvulsants used. Our results show the teratogenicity of epilepsy by itself, the synergistic effect of some anticonvulsants, and the need of an appropriate periconceptional control of the disease and treatment.

  17. Enhanced magnetostriction derived from magnetic single domain structures in cluster-assembled SmCo films

    NASA Astrophysics Data System (ADS)

    Bai, Yulong; Yang, Bo; Guo, Fei; Lu, Qingshan; Zhao, Shifeng

    2017-11-01

    Cluster-assembled SmCo alloy films were prepared by low energy cluster beam deposition. The structure, magnetic domain, magnetization, and magnetostriction of the films were characterized. It is shown that the as-prepared films are assembled in compact and uniformly distributed spherical cluster nanoparticles, most of which, after vacuum in situ annealing at 700 K, aggregated to form cluster islands. These cluster islands result in transformations from superparamagnetic states to magnetic single domain (MSD) states in the films. Such MSD structures contribute to the enhanced magnetostrictive behaviors with a saturation magnetostrictive coefficient of 160 × 10-6 in comparison to 105 × 10-6 for the as-prepared films. This work demonstrates candidate materials that could be applied in nano-electro-mechanical systems, low power information storage, and weak magnetic detecting devices.

  18. Determination of mechanical behavior of nanoscale materials using molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Heo, Seongjun

    It is important to understand the mechanical properties of nanometer-scale materials for use in such applications as microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS). These properties are difficult to measure directly using experimental methods due to their small sizes. Computational simulations provide important insights that complement experimental data and lead to improved understanding of the mechanical properties of nanometer-scale systems. Molecular dynamics (MD) simulations, which are used to investigate the properties of materials at the atomic scale, is used in my research to determine (1) best thermostat managing way for acceptable mechanical behavior of nanoscale systems; (2) filling effect on the bending and compressive properties of carbon nanotubes (CNTs); (3) vibrational behavior of bridged and cantilevered CNT bombarded by external fluid atoms; (4) frictional behavior of filled CNT bundles and the effect of external molecules on friction; (5) effect of sliding orientations on the tribological properties of polyethylene (PE). In all the simulations the reactive empirical bond-order (REBO) potential combined with the Lennard Jones potential is applied to control inter-atomic interactions. During the MD simulations, thermostats are used to maintain the system temperature at a constant value. Tests indicate that the simulations describe the mechanical behavior of CNTs differently depending on the type of thermostat used, and the relative fraction of the system to which the thermostat is applied. The results indicate that Langevin and velocity rescaling thermostats are more reliable for temperature control than the Nose-Hoover thermostat. In examining CNT bending and compression, the simulations predict filled CNTs are more resistant to external bending and compressive forces than hollow CNTs. The mechanical properties deteriorate with increases in temperature and number of CNT wall defects. MD simulations of the vibrational

  19. Oil and Gas Supply Module - NEMS Documentation

    EIA Publications

    2017-01-01

    Defines the objectives of the Oil and Gas Supply Model (OGSM), to describe the model's basic approach, and to provide detail on how the model works. This report is intended as a reference document for model analysts, users, and the public.

  20. State Energy Efficiency Program Evaluation Inventory

    EIA Publications

    2013-01-01

    The focus of this inventory, some of which has been placed into a searchable spreadsheet, is to support the National Energy Modeling System (NEMS) and to research cost information in state-mandated energy efficiency program evaluations – e.g., for use in updating analytic and modeling assumptions used by the U.S. Energy Information Administration (EIA).

  1. Evaluation of the implementation outcomes of the Essential Medicines System in Anhui county-level public hospitals: a before-and-after study.

    PubMed

    Xu, Shuman; Bian, Cheng; Wang, Heng; Li, Niannian; Wu, Jingya; Li, Peng; Lu, Hua

    2015-09-22

    In August 2009, China formally established the National Essential Medicines System (NEMS) and implemented this system in the government-funded primary care medical and health institutions. After nearly four years of practice, the system has already been generalized to the county-level public hospitals. This study aimed to examine the impact on the operation of the hospitals through implementing the NEMS in Anhui Province and put forward some improvement measures. For quantitative analyses, we distributed 21 questionnaires to 21 county-level public hospitals in Anhui Province, which had implemented the national public hospital reform. Twenty valid questionnaires were returned, response rate was 95.2 %. Questions covered storage, usage and supply of essential medicines, compensation mechanisms, insurance policies, hospital incomes, service amounts and fees from January to June in each of the years from 2011 to 2013. For qualitative study, we chose three from 21 hospitals based on geographical distribution and conducted focus group interviews based on a planned interview outline centered on the implementation status of the system. Following implementation, the types of essential medicines stocked and the proportion of total sales that were composed of essential medicines have increased but do not yet meet the required standards issued in the government document, which was not less than 95 % and 30 % of the total, respectively. The average financial subsidies had increased by 1,665,200 yuan, and significant increases appeared in provincial financial assistance. The average inpatient fees per visit decreased by 487.41 yuan. Increases in income from medicines during hospitalization led to increases in per-visit hospitalization fees. Unexpectedly, higher financial assistance revenue also led to higher average per-visit hospitalization fees. The guiding role of the National Essential Medicines List remains to be reinforced, and specific lists for county hospitals should be

  2. I-V characteristics of in-plane and out-of-plane strained edge-hydrogenated armchair graphene nanoribbons

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cartamil-Bueno, S. J., E-mail: s.j.cartamilbueno@tudelft.nl, E-mail: rbolivar@ugr.es; Rodríguez-Bolívar, S., E-mail: s.j.cartamilbueno@tudelft.nl, E-mail: rbolivar@ugr.es

    2015-06-28

    The effects of tensile strain on the current-voltage (I-V) characteristics of hydrogenated-edge armchair graphene nanoribbons are investigated by using DFT theory. The strain is introduced in two different ways related to the two types of systems studied in this work: in-plane strained systems (A) and out-of-plane strained systems due to bending (B). These two kinds of strain lead to make a distinction among three cases: in-plane strained systems with strained electrodes (A1) and with unstrained electrodes (A2), and out-of-plane homogeneously strained systems with unstrained, fixed electrodes (B). The systematic simulations to calculate the electronic transmission between two electrodes were focusedmore » on systems of 8 and 11 dimers in width. The results show that the differences between cases A2 and B are negligible, even though the strain mechanisms are different: in the plane case, the strain is uniaxial along its length; while in the bent case, the strain is caused by the arc deformation. Based on the study, a new type of nanoelectromechanical system solid state switching device is proposed.« less

  3. Linear pi-Acceptor-Templated Dynamic Clipping to Macrobicycles and[2]Rotaxanes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Klivansky, Liana M.; Koshkakaryan, Gayane; Cao, Dennis

    2009-04-30

    Functional rotaxanes are one of the representative nanoscale molecular machines that have found applications in many areas, including molecular electronics, nanoelectromechanical systems (NEMS), photo controllable smart surfaces, and nanovalves. With the advent of molecular recognition and self-assembly, such molecular compounds can now be obtained efficiently through template-directed synthesis. One of the common strategies of making [2]rotaxanes involves the clipping of a macrocycle around a preformed dumbbell-shaped template in a [1+1] or [2+2] manner. While early examples were based on irreversible kinetic pathway through covalent bond formation, recent advances on reversible dynamic covalent chemistry (DCC) has attracted great attention to thismore » field. By virtue of thermodynamically controlled equilibria, DCC has provided highly efficient and versatile synthetic routes in the selection of specific products from a complex system. Among the several reversible reactions in the category of DCC reactions, the imine formation has proven to be very versatile in macrocyclization to give complex interlocked molecular compounds. Cryptands are three dimensional bicyclic hosts with preorganized cavities capable of inclusion of ions and small molecules. Replacing the nitrogen bridgeheads in common cryptands with aromatic ring systems gives cyclophane-based macrobicycles. The introduction of aromatic ring systems into a preorganized cage-like geometry facilitates ion-{pi} interactions and {pi}-{pi} interactions, resulting in novel metal sandwiches, fluoride receptors, and host-guest complexes. In particular, the seminal work by Gibson, Huang and coworkers on cryptand complexation with paraquat and diquat guests have resulted in the efficient synthesis of mechanically interlocked rotaxanes. The synthesis of cyclophane-based macrobicycles, however, was mostly realized through multiple reaction steps and in high-dilution conditions, which often suffered from low yield

  4. Modelling the Size Effects on the Mechanical Properties of Micro/Nano Structures.

    PubMed

    Abazari, Amir Musa; Safavi, Seyed Mohsen; Rezazadeh, Ghader; Villanueva, Luis Guillermo

    2015-11-11

    Experiments on micro- and nano-mechanical systems (M/NEMS) have shown that their behavior under bending loads departs in many cases from the classical predictions using Euler-Bernoulli theory and Hooke's law. This anomalous response has usually been seen as a dependence of the material properties on the size of the structure, in particular thickness. A theoretical model that allows for quantitative understanding and prediction of this size effect is important for the design of M/NEMS. In this paper, we summarize and analyze the five theories that can be found in the literature: Grain Boundary Theory (GBT), Surface Stress Theory (SST), Residual Stress Theory (RST), Couple Stress Theory (CST) and Surface Elasticity Theory (SET). By comparing these theories with experimental data we propose a simplified model combination of CST and SET that properly fits all considered cases, therefore delivering a simple (two parameters) model that can be used to predict the mechanical properties at the nanoscale.

  5. Modelling the Size Effects on the Mechanical Properties of Micro/Nano Structures

    PubMed Central

    Abazari, Amir Musa; Safavi, Seyed Mohsen; Rezazadeh, Ghader; Villanueva, Luis Guillermo

    2015-01-01

    Experiments on micro- and nano-mechanical systems (M/NEMS) have shown that their behavior under bending loads departs in many cases from the classical predictions using Euler-Bernoulli theory and Hooke’s law. This anomalous response has usually been seen as a dependence of the material properties on the size of the structure, in particular thickness. A theoretical model that allows for quantitative understanding and prediction of this size effect is important for the design of M/NEMS. In this paper, we summarize and analyze the five theories that can be found in the literature: Grain Boundary Theory (GBT), Surface Stress Theory (SST), Residual Stress Theory (RST), Couple Stress Theory (CST) and Surface Elasticity Theory (SET). By comparing these theories with experimental data we propose a simplified model combination of CST and SET that properly fits all considered cases, therefore delivering a simple (two parameters) model that can be used to predict the mechanical properties at the nanoscale. PMID:26569256

  6. Linear feature projection-based real-time decoding of limb state from dorsal root ganglion recordings.

    PubMed

    Han, Sungmin; Chu, Jun-Uk; Park, Jong Woong; Youn, Inchan

    2018-05-15

    Proprioceptive afferent activities recorded by a multichannel microelectrode have been used to decode limb movements to provide sensory feedback signals for closed-loop control in a functional electrical stimulation (FES) system. However, analyzing the high dimensionality of neural activity is one of the major challenges in real-time applications. This paper proposes a linear feature projection method for the real-time decoding of ankle and knee joint angles. Single-unit activity was extracted as a feature vector from proprioceptive afferent signals that were recorded from the L7 dorsal root ganglion during passive movements of ankle and knee joints. The dimensionality of this feature vector was then reduced using a linear feature projection composed of projection pursuit and negentropy maximization (PP/NEM). Finally, a time-delayed Kalman filter was used to estimate the ankle and knee joint angles. The PP/NEM approach had a better decoding performance than did other feature projection methods, and all processes were completed within the real-time constraints. These results suggested that the proposed method could be a useful decoding method to provide real-time feedback signals in closed-loop FES systems.

  7. Nanoscale deformation measurements for reliability assessment of material interfaces

    NASA Astrophysics Data System (ADS)

    Keller, Jürgen; Gollhardt, Astrid; Vogel, Dietmar; Michel, Bernd

    2006-03-01

    With the development and application of micro/nano electronic mechanical systems (MEMS, NEMS) for a variety of market segments new reliability issues will arise. The understanding of material interfaces is the key for a successful design for reliability of MEMS/NEMS and sensor systems. Furthermore in the field of BIOMEMS newly developed advanced materials and well known engineering materials are combined despite of fully developed reliability concepts for such devices and components. In addition the increasing interface-to volume ratio in highly integrated systems and nanoparticle filled materials are challenges for experimental reliability evaluation. New strategies for reliability assessment on the submicron scale are essential to fulfil the needs of future devices. In this paper a nanoscale resolution experimental method for the measurement of thermo-mechanical deformation at material interfaces is introduced. The determination of displacement fields is based on scanning probe microscopy (SPM) data. In-situ SPM scans of the analyzed object (i.e. material interface) are carried out at different thermo-mechanical load states. The obtained images are compared by grayscale cross correlation algorithms. This allows the tracking of local image patterns of the analyzed surface structure. The measurement results are full-field displacement fields with nanometer resolution. With the obtained data the mixed mode type of loading at material interfaces can be analyzed with highest resolution for future needs in micro system and nanotechnology.

  8. Pull-in instability of paddle-type and double-sided NEMS sensors under the accelerating force

    NASA Astrophysics Data System (ADS)

    Keivani, M.; Khorsandi, J.; Mokhtari, J.; Kanani, A.; Abadian, N.; Abadyan, M.

    2016-02-01

    Paddle-type and double-sided nanostructures are potential for use as accelerometers in flying vehicles and aerospace applications. Herein the pull-in instability of the cantilever paddle-type and double-sided sensors in the Casimir regime are investigated under the acceleration. The D'Alembert principle is employed to transform the accelerating system into an equivalent static system by incorporating the accelerating force. Based on the couple stress theory (CST), the size-dependent constitutive equations of the sensors are derived. The governing nonlinear equations are solved by two approaches, i.e. modified variational iteration method and finite difference method. The influences of the Casimir force, geometrical parameters, acceleration and the size phenomenon on the instability performance have been demonstrated. The obtained results are beneficial to design and fabricate paddle-type and double-sided accelerometers.

  9. Emergence of vancomycin resistance in the genus Streptococcus: characterization of a vanB transferable determinant in Streptococcus bovis.

    PubMed Central

    Poyart, C; Pierre, C; Quesne, G; Pron, B; Berche, P; Trieu-Cuot, P

    1997-01-01

    Streptococcus bovis NEM760 was isolated from a stool swab collected on admission from a patient as surveillance for vancomycin-resistant enterococci. Strain NEM760 was identified as S. bovis by conventional biochemical methods and partial sequence analysis of its 16S rRNA. This strain was resistant to a low level of vancomycin (MIC, 64 micrograms/ml) but was susceptible to teicoplanin (MIC, 1 micrograms/ml), and vancomycin induced resistance to both glycopeptides. The presence of a vanB-related gene in NEM760 was demonstrated in a PCR assay which enabled specific amplification of a 635-hp internal segment of vanB. Sequence analysis of the corresponding PCR product revealed that it was highly homologous (96% identity) to the prototype vanB sequence of Enterococcus faecalis V583. The VanB resistance of determinant of S. bovis NEM760 was transferred by conjugation to E. faecalis and Enterococcus faecium at a similar frequency of 2 x 10(-5) per donor. SmaI-digested genomic DNAs of independently obtained transconjugants of E. faecalis and E. faecium were analyzed by pulsed-field gel electrophoresis and Southern hybridization with a vanB DNA probe. The electrophoretic and hybridization patterns obtained with all transconjugants of the same species were indistinguishable and revealed vanB-containing chromosomal insertions of approximately 100 kb. These results suggest that the genes mediating VanB-type resistance in S. bovis NEM760 are part of large transferable genetic elements. The results presented in the report demonstrate for the first time the role of streptococci in the dissemination of vancomycin resistance among gram-positive bacteria. PMID:8980749

  10. Nanomechanics modeling of carbon nanotubes interacting with surfaces in various configurations

    NASA Astrophysics Data System (ADS)

    Wu, Yu-Chiao

    Carbon nanotubes (CNTs) have been widely used as potential components in reported nanoelectromechanical (NEM) devices due to their excellent mechanical and electrical properties. This thesis models the experiments by the continuum mechanics in two distinct scenarios. In the first situation, measurements are made of CNT configurations after manipulations. Modeling is then used to determine the interfacial properties during the manipulation which led to the observed configuration. This technique is used to determine the shear stress between a SWNT bundle and other materials. During manipulation, a SWNT bundle slipped on two micro-cantilevers. According to the slack due to the slippage after testing and the device configuration, the shear stress between a SWNT bundle and other materials can be determined. In another model, the work of adhesion was determined on two accidentally fabricated devices. Through the configuration of two SWNT adhered bundles and the force-distance curves measured by an atomic force microscope (AFM), modeling was used to determine the work of adhesion between two bundles and the shear stress at the SWNT-substrate interface. In the second situation, modeling is used in a more traditional fashion to make theoretical predictions as to how a device will operate. Using this technique, the actuation mechanism of a single-trench SWNT-based switch was investigated. During the actuation, the deflection-induced tension causes the SWNT bundle to slip on both platforms and to be partially peeled from two side recessed electrodes. These effects produce a slack which reduces the threshold voltages subsequent to the first actuation. The result shows excellent agreement between the theory and the measurement. Furthermore, the operation of a double-trenched SWNT-based switch was investigated. A slack is produced in the 1st actuated trench region by the slip and peeling effects. This slack reduces the 2nd actuation voltage in the neighbor trench. Finally, the

  11. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Atanasov, Petar A., E-mail: paatanas@ie.bas.bg; Nedyalkov, Nikolay N.; Valova, Eugenia I.

    We present an experimental analysis on surface structuring of polydimethylsiloxane films with UV (263 nm) femtosecond laser pulses, in air. Laser processed areas are analyzed by optical microscopy, SEM, and μ-Raman spectroscopy. The laser-treated sample shows the formation of a randomly nanostructured surface morphology. μ-Raman spectra, carried out at both 514 and 785 nm excitation wavelengths, prior and after laser treatment allow evidencing the changes in the sample structure. The influence of the laser fluence on the surface morphology is studied. Finally, successful electro-less metallization of the laser-processed sample is achieved, even after several months from the laser-treatment contrary to previous observationmore » with nanosecond pulses. Our findings address the effectiveness of fs-laser treatment and chemical metallization of polydimethylsiloxane films with perspective technological interest in micro-fabrication devices for MEMS and nano-electromechanical systems.« less

  12. Electrostatically Driven Nanoballoon Actuator.

    PubMed

    Barzegar, Hamid Reza; Yan, Aiming; Coh, Sinisa; Gracia-Espino, Eduardo; Dunn, Gabriel; Wågberg, Thomas; Louie, Steven G; Cohen, Marvin L; Zettl, Alex

    2016-11-09

    We demonstrate an inflatable nanoballoon actuator based on geometrical transitions between the inflated (cylindrical) and collapsed (flattened) forms of a carbon nanotube. In situ transmission electron microscopy experiments employing a nanoelectromechanical manipulator show that a collapsed carbon nanotube can be reinflated by electrically charging the nanotube, thus realizing an electrostatically driven nanoballoon actuator. We find that the tube actuator can be reliably cycled with only modest control voltages (few volts) with no apparent wear or fatigue. A complementary theoretical analysis identifies critical parameters for nanotube nanoballoon actuation.

  13. Nutrition environment measures survey-vending: development, dissemination, and reliability.

    PubMed

    Voss, Carol; Klein, Susan; Glanz, Karen; Clawson, Margaret

    2012-07-01

    Researchers determined a need to develop an instrument to assess the vending machine environment that was comparably reliable and valid to other Nutrition Environment Measures Survey tools and that would provide consistent and comparable data for businesses, schools, and communities. Tool development, reliability testing, and dissemination of the Nutrition Environment Measures Survey-Vending (NEMS-V) involved a collaboration of students, professionals, and community leaders. Interrater reliability testing showed high levels of agreement among trained raters on the products and evaluations of products. NEMS-V can benefit public health partners implementing policy and environmental change initiatives as a part of their community wellness activities. The vending machine project will support a policy calling for state facilities to provide a minimum of 30% of foods and beverages in vending machines as healthy options, based on NEMS-V criteria, which will be used as a model for other businesses.

  14. Seasonal and interannual patterns in primary production ...

    EPA Pesticide Factsheets

    Measurements of primary production and respiration provide fundamental information about the trophic status of aquatic ecosystems, yet such measurements are logistically difficult and expensive to sustain as part of long-term monitoring programs. However, ecosystem metabolism parameters can be inferred from high frequency water quality data collections using autonomous logging instruments. For this study, we analyzed such time series datasets from three Gulf of Mexico estuaries: Grand Bay, MS, Weeks Bay AL and Apalachicola Bay FL. Data were acquired from NOAA's National Estuarine Research Reserve System Wide Monitoring Program and used to calculate gross primary production (GPP), ecosystem respiration (ER) and net ecosystem metabolism (NEM) using Odum's open water method. The three systems present a diversity of estuaries typical of the Gulf of Mexico region, varying by as much as 2 orders of magnitude in key physical characteristics, such as estuarine area, watershed area, freshwater flow, and nutrient loading. In all three systems, gross primary production (GPP) and ecosystem respiration (ER) displayed strong seasonality, peaking in summer and being lowest during winter. Peak rates of GPP and ER exceeded 200 mmol O2 m-2 d-1 52 in all three estuaries. To our knowledge, this is the only study examining long term trends in rates of GPP, ER and NEM in estuaries. Variability in metabolism tended to be small among sites within each estuary. Nitrogen loading was high

  15. Studies on the plasma membrane H sup + -ATPase of oat roots: Preparation and assay, cytological localization, and sulfhydryl chemistry

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Katz, D.B.

    1989-01-01

    Biochemical and cytological studies were performed on the plasma membrane proton pump (H{sup +}-ATPase) of oat roots (Avena sativa cv. Stout). H{sup +}-ATPase activity in oat root plasma membranes is inhibited by N-ethylmaleimide (NEM), a covalent modifier of protein sulfhydryl groups. The rate of inhibition is reduced in the presence of ADP or MgADP. An M{sub r} = 100,000 plasma membrane polypeptide showed reduced labelling by ({sup 3}H)NEM in the presence of ADP. When tryptic peptides from ({sup 3}H)NEM-labeled M{sub r} = 100,000 polypeptide were separated by reverse-phase high-pressure liquid chromatography (HPLC), only one radioactive peak consistently showed labeling inmore » the presence of ADP. In order to determine the location and identity of the NEM-reactive residue, the radioactive peptide in this peak was further purified by HPLC. The amino acid sequence(s) in the resulting sample were then determined by Edman degradation on an automated gas-phase sequenator. The PTH-amino acids released at each cycle of the degradation were separated by HPLC. Analysis of the chromatograms suggested that the radio-labeled residue was located in a peptide of sequence V-E-N-Q-D-A-I-D-A-C{sup *}-M-V-G-M-L-A-D-P-K. The NEM-reactive residue was cysteine, based on the retention time of the radioactivity released. The ATP-hydrolyzing activity observed in electron micrographs by lead-precipitation of enzymically released inorganic phosphate was compared with that observed in in vitro assays of the soluble and plasma membrane fractions of oat root homogenates. Although an ATP-hydrolyzing activity was observed on the plasma membrane in the electron micrographs, its substrate specificity and inhibitor sensitivity was identical to that observed for phosphatase activity.« less

  16. Antibodies and a cysteine-modifying reagent show correspondence of M current in neurons to KCNQ2 and KCNQ3 K+ channels

    PubMed Central

    Roche, John P; Westenbroek, Ruth; Sorom, Abraham J; Hille, Bertil; Mackie, Ken; Shapiro, Mark S

    2002-01-01

    KCNQ K+ channels are thought to underlie the M current of neurons. To probe if the KCNQ2 and KCNQ3 subtypes underlie the M current of rat superior cervical ganglia (SCG) neurons and of hippocampus, we raised specific antibodies against them and also used the cysteine-alkylating agent N-ethylmaleimide (NEM) as an additional probe of subunit composition. Tested on tsA-201 (tsA) cells transfected with cloned KCNQ1-5 subunits, our antibodies showed high affinity and selectivity for the appropriate subtype. The antibodies immunostained SCG neurons and hippocampal sections at levels similar to those for channels expressed in tsA cells, indicating that KCNQ2 and KCNQ3 are present in SCG and hippocampal neurons. Some hippocampal regions contained only KCNQ2 or KCNQ3 subunits, suggesting the presence of M currents produced by channels other than KCNQ2/3 heteromultimers. We found that NEM augmented M currents in SCG neurons and KCNQ2/3 currents in tsA cells via strong voltage-independent and modest voltage-dependent actions. Expression of individual KCNQ subunits in tsA cells revealed voltage-independent augmentation of KCNQ2, but not KCNQ1 nor KCNQ3, currents by NEM indicating that this action on SCG M currents likely localizes to KCNQ2. Much of the voltage-independent action is lost after the C242T mutation in KCNQ2. The correspondence of NEM effects on expressed KCNQ2/3 and SCG M currents, along with the antibody labelling, provide further evidence that KCNQ2 and KCNQ3 subunits strongly contribute to the M current of neurons. The site of NEM action may be important for treatment of diseases caused by under-expression of these channels. PMID:12466226

  17. Atomistic aspects of ductile responses of cubic silicon carbide during nanometric cutting.

    PubMed

    Goel, Saurav; Luo, Xichun; Reuben, Robert L; Rashid, Waleed Bin

    2011-11-11

    Cubic silicon carbide (SiC) is an extremely hard and brittle material having unique blend of material properties which makes it suitable candidate for microelectromechanical systems and nanoelectromechanical systems applications. Although, SiC can be machined in ductile regime at nanoscale through single-point diamond turning process, the root cause of the ductile response of SiC has not been understood yet which impedes significant exploitation of this ceramic material. In this paper, molecular dynamics simulation has been carried out to investigate the atomistic aspects of ductile response of SiC during nanometric cutting process. Simulation results show that cubic SiC undergoes sp3-sp2 order-disorder transition resulting in the formation of SiC-graphene-like substance with a growth rate dependent on the cutting conditions. The disorder transition of SiC causes the ductile response during its nanometric cutting operations. It was further found out that the continuous abrasive action between the diamond tool and SiC causes simultaneous sp3-sp2 order-disorder transition of diamond tool which results in graphitization of diamond and consequent tool wear.

  18. Disintegration of nano-embedded microparticles after deposition on mucus: A mechanistic study.

    PubMed

    Ruge, Christian A; Bohr, Adam; Beck-Broichsitter, Moritz; Nicolas, Valérie; Tsapis, Nicolas; Fattal, Elias

    2016-03-01

    The conversion of colloidal drug carriers/polymeric nanoparticles into dry microparticulate powders (e.g., by spray-drying) is a prominent approach to overcome the aerodynamic limitations of these formulations for delivery via inhalation. However, to what extent such nano-embedded microparticles disintegrate into individual/intact nanoparticles after contacting relevant physiological media has so far not been addressed. Polymeric nanoparticles were spray-dried into nano-embedded microparticles (NEMs) using different amounts of trehalose as embedding matrix excipient. Formulations were characterized and then evaluated for their disintegration behavior after aerosolization onto model mucus. Although a rapid and complete aqueous redispersion was observed for specific excipient/nanoparticle weight ratios (i.e., greater than 1/1), the same formulations revealed no disintegration after deposition onto a static mucus layer. Double-labeled NEMs powders (i.e., dual color staining of polymeric nanoparticles and trehalose) demonstrated rapid matrix dissolution, while the nanoparticle aggregates persisted. When deposited onto agitated mucus, however, sufficient disintegration of NEMs into individual polymeric nanoparticles was observed. These findings indicate that mechanical forces are necessary to overcome the attraction between individual nanoparticles found within the NEMs. Thus, it remains questionable whether the lung mechanics (e.g., breathing, mucociliary clearance) acting on these formulations will contribute to the overall disintegration process. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. International energy outlook 1996

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    NONE

    1996-05-01

    This International Energy Outlook presents historical data from 1970 to 1993 and EIA`s projections of energy consumption and carbon emissions through 2015 for 6 country groups. Prospects for individual fuels are discussed. Summary tables of the IEO96 world energy consumption, oil production, and carbon emissions projections are provided in Appendix A. The reference case projections of total foreign energy consumption and of natural gas, coal, and renewable energy were prepared using EIA`s World Energy Projection System (WEPS) model. Reference case projections of foreign oil production and consumption were prepared using the International Energy Module of the National Energy Modeling Systemmore » (NEMS). Nuclear consumption projections were derived from the International Nuclear Model, PC Version (PC-INM). Alternatively, nuclear capacity projections were developed using two methods: the lower reference case projections were based on analysts` knowledge of the nuclear programs in different countries; the upper reference case was generated by the World Integrated Nuclear Evaluation System (WINES)--a demand-driven model. In addition, the NEMS Coal Export Submodule (CES) was used to derive flows in international coal trade. As noted above, foreign projections of electricity demand are now projected as part of the WEPS. 64 figs., 62 tabs.« less

  20. The Quantum-to-Classical Transition in Strongly Interacting Nanoscale Systems

    NASA Astrophysics Data System (ADS)

    Benatov, Latchezar Latchezarov

    This thesis comprises two separate but related studies, dealing with two strongly interacting nanoscale systems on the border between the quantum and classical domains. In Part 1, we use a Born-Markov approximated master equation approach to study the symmetrized-in-frequency current noise spectrum and the oscillator steady state of a nanoelectromechanical system where a nanoscale resonator is coupled linearly via its momentum to a quantum point contact (QPC). Our current noise spectra exhibit clear signatures of the quantum correlations between the QPC current and the back-action force on the oscillator at a value of the relative tunneling phase where such correlations are expected to be maximized. We also show that the steady state of the oscillator obeys a classical Fokker-Planck equation, but can experience thermomechanical noise squeezing in the presence of a momentum-coupled detector bath and a position-coupled environmental bath. Besides, the full master equation clearly shows that half of the detector back-action is correlated with electron tunneling, indicating a departure from the model of the detector as an effective bath and suggesting that a future calculation valid at lower bias voltage, stronger tunneling and/or stronger coupling might reveal interesting quantum effects in the oscillator dynamics. In the second part of the thesis, we study the subsystem dynamics and thermalization of an oscillator-spin star model, where a nanomechanical resonator is coupled to a few two-level systems (TLS's). We use a fourth-order Runge-Kutta numerical algorithm to integrate the Schrodinger equation for the system and obtain our results. We find that the oscillator reaches a Boltzmann steady state when the TLS bath is initially in a thermal state at a temperature higher than the oscillator phonon energy. This occurs in both chaotic and integrable systems, and despite the small number of spins (only six) and the lack of couplings between them. At the same time, pure

  1. Grid-Connected Distributed Generation: Compensation Mechanism Basics

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Aznar, Alexandra Y; Zinaman, Owen R

    2017-10-02

    This short report defines compensation mechanisms for grid-connected, behind-the-meter distributed generation (DG) systems as instruments that comprise three core elements: (1) metering and billing arrangements, (2) sell rate design, and (3) retail rate design. This report describes metering and billing arrangements, with some limited discussion of sell rate design. We detail the three possible arrangements for metering and billing of DG: net energy metering (NEM); buy all, sell all; and net billing.

  2. Summary Impacts of Modeled Provisions of the 2003 Conference Energy Bill

    EIA Publications

    2004-01-01

    This service report was undertaken at the February 2, 2004, request of Senator John Sununu to perform an assessment of the Conference Energy Bill of 2003. This report summarizes the CEB provisions that can be analyzed using the National Energy Modeling System (NEMS) and have the potential to affect energy consumption, supply, and prices. The impacts are estimated by comparing the projections with the CEB provisions to the AEO2004 Reference Case.

  3. Height Growth and Percentage of Body Fat in Relation to Early Menarche in Girls from Merida, Yucatan, Mexico.

    PubMed

    Datta Banik, Sudip; Mendez, Nina; Dickinson, Federico

    2015-01-01

    Early menarche (EM) (i.e., age at menarche [AAM] <12 years of age) is related to short height and higher body fatness. In a mixed-longitudinal study done in Merida, Yucatan, height, body mass index (BMI), and percentage of body fat (BF%) were recorded at a one-year interval among 258 postmenarcheal (EM = 94) girls. Anthropometric measurements were recorded of the age cohorts in 2008-09 when participants were 13-17 years of age (baseline), and in the one-year follow-up study (± 6 days) the girls were 14-18 years of age. The BF% was estimated through bioelectrical impedance analysis. Mean AAM was 10.59 years in EM girls and 12.54 years in not early menarche (NEM) girls. Height growth (cm/year) was greater in NEM girls. Mean values of BMI, BF%, and frequencies of stunting (low height-for-age) and excess weight (overweight + obesity) were higher in EM girls than in their NEM age peers.

  4. Interferometric imaging of nonlocal electromechanical power transduction in ferroelectric domains.

    PubMed

    Zheng, Lu; Dong, Hui; Wu, Xiaoyu; Huang, Yen-Lin; Wang, Wenbo; Wu, Weida; Wang, Zheng; Lai, Keji

    2018-05-22

    The electrical generation and detection of elastic waves are the foundation for acoustoelectronic and acoustooptic systems. For surface acoustic wave devices, microelectromechanical/nanoelectromechanical systems, and phononic crystals, tailoring the spatial variation of material properties such as piezoelectric and elastic tensors may bring significant improvements to the system performance. Due to the much slower speed of sound than speed of light in solids, it is desirable to study various electroacoustic behaviors at the mesoscopic length scale. In this work, we demonstrate the interferometric imaging of electromechanical power transduction in ferroelectric lithium niobate domain structures by microwave impedance microscopy. In sharp contrast to the traditional standing-wave patterns caused by the superposition of counterpropagating waves, the constructive and destructive fringes in microwave dissipation images exhibit an intriguing one-wavelength periodicity. We show that such unusual interference patterns, which are fundamentally different from the acoustic displacement fields, stem from the nonlocal interaction between electric fields and elastic waves. The results are corroborated by numerical simulations taking into account the sign reversal of piezoelectric tensor in oppositely polarized domains. Our work paves ways to probe nanoscale electroacoustic phenomena in complex structures by near-field electromagnetic imaging.

  5. A review on nanomechanical resonators and their applications in sensors and molecular transportation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Arash, Behrouz; Rabczuk, Timon, E-mail: timon.rabczuk@uni-weimar.de; Jiang, Jin-Wu

    2015-06-15

    Nanotechnology has opened a new area in science and engineering, leading to the development of novel nano-electromechanical systems such as nanoresonators with ultra-high resonant frequencies. The ultra-high-frequency resonators facilitate wide-ranging applications such as ultra-high sensitive sensing, molecular transportation, molecular separation, high-frequency signal processing, and biological imaging. This paper reviews recent studies on dynamic characteristics of nanoresonators. A variety of theoretical approaches, i.e., continuum modeling, molecular simulations, and multiscale methods, in modeling of nanoresonators are reviewed. The potential application of nanoresonators in design of sensor devices and molecular transportation systems is introduced. The essence of nanoresonator sensors for detection of atomsmore » and molecules with vibration and wave propagation analyses is outlined. The sensitivity of the resonator sensors and their feasibility in detecting different atoms and molecules are particularly discussed. Furthermore, the applicability of molecular transportation using the propagation of mechanical waves in nanoresonators is presented. An extended application of the transportation methods for building nanofiltering systems with ultra-high selectivity is surveyed. The article aims to provide an up-to-date review on the mechanical properties and applications of nanoresonators, and inspire additional potential of the resonators.« less

  6. On the Path to SunShot. Utility Regulatory and Business Model Reforms for Addressing the Financial Impacts of Distributed Solar on Utilities

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Barbose, Galen; Miller, John; Sigrin, Ben

    Net-energy metering (NEM) has helped drive the rapid growth of distributed PV (DPV) but has raised concerns about electricity cost shifts, utility financial losses, and inefficient resource allocation. These concerns have motivated real and proposed reforms to utility regulatory and business models. This report explores the challenges and opportunities associated with such reforms in the context of the U.S. Department of Energy's SunShot Initiative. Most of the reforms to date address NEM concerns by reducing the benefits provided to DPV customers and thus constraining DPV deployment. Eliminating NEM nationwide, by compensating exports of PV electricity at wholesale rather than retailmore » rates, could cut cumulative DPV deployment by 20% in 2050 compared with a continuation of current policies. This would slow the PV cost reductions that arise from larger scale and market certainty. It could also thwart achievement of the SunShot deployment goals even if the initiative's cost targets are achieved. This undesirable prospect is stimulating the development of alternative reform strategies that address concerns about distributed PV compensation without inordinately harming PV economics and growth. These alternatives fall into the categories of facilitating higher-value DPV deployment, broadening customer access to solar, and aligning utility profits and earnings with DPV. Specific strategies include utility ownership and financing of DPV, community solar, distribution network operators, services-driven utilities, performance-based incentives, enhanced utility system planning, pricing structures that incentivize high-value DPV configurations, and decoupling and other ratemaking reforms that reduce regulatory lag. These approaches represent near- and long-term solutions for preserving the legacy of the SunShot Initiative.« less

  7. Turning the undesired voids in silicon into a tool: In-situ fabrication of free-standing 3C-SiC membranes

    NASA Astrophysics Data System (ADS)

    Khazaka, Rami; Michaud, Jean François; Vennéguès, Philippe; Alquier, Daniel; Portail, Marc

    2017-02-01

    In this contribution, we present a method to form free-standing cubic silicon carbide (3C-SiC) membranes in-situ during the growth stage. To do so, we exploit the presence of voids in the silicon (Si) epilayer underneath the 3C-SiC membrane, in stark contrast to the conventional view of voids as defects. The shape and the size of the 3C-SiC membranes can be controlled by a preceding patterning step of the Si epilayer. Afterwards, by controlling the expansion of voids in Si, the structured sacrificial layer is consumed during the 3C-SiC growth step. Consequently, the membranes are grown and released simultaneously in a single step process. This straightforward technique is expected to markedly simplify the fabrication process of membranes by reducing the fabrication duration and cost. Furthermore, it helps to overcome several technical issues and presents the cornerstone for micro and nano-electromechanical systems applications, profiting from the outstanding properties of cubic silicon carbide.

  8. Built-in Electric Field Induced Mechanical Property Change at the Lanthanum Nickelate/Nb-doped Strontium Titanate Interfaces

    DOE PAGES

    Chien, TeYu; Liu, Jian; Yost, Andrew J.; ...

    2016-01-08

    The interactions between electric field and the mechanical properties of materials are important for the applications of microelectromechanical and nanoelectromechanical systems, but relatively unexplored for nanoscale materials. Here, we observe an apparent correlation between the change of the fractured topography of Nb-doped SrTiO 3 (Nb:STO) within the presence of a built-in electric field resulting from the Schottky contact at the interface of a metallic LaNiO 3 thin film utilizing cross-sectional scanning tunneling microscopy and spectroscopy. The change of the inter-atomic bond length mechanism is argued to be the most plausible origin. This picture is supported by the strong-electric-field-dependent permittivity inmore » STO and the existence of the dielectric dead layer at the interfaces of STO with metallic films. Finally, these results provided direct evidence and a possible mechanism for the interplay between the electric field and the mechanical properties on the nanoscale for perovskite materials.« less

  9. Fabrication and characterization of GaN nanowire doubly clamped resonators

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Maliakkal, Carina B., E-mail: carina@tifr.res.in; Mathew, John P.; Hatui, Nirupam

    2015-09-21

    Gallium nitride (GaN) nanowires (NWs) have been intensely researched as building blocks for nanoscale electronic and photonic device applications; however, the mechanical properties of GaN nanostructures have not been explored in detail. The rigidity, thermal stability, and piezoelectric properties of GaN make it an interesting candidate for nano-electromechanical systems. We have fabricated doubly clamped GaN NW electromechanical resonators on sapphire using electron beam lithography and estimated the Young's modulus of GaN from resonance frequency measurements. For wires of triangular cross section with side ∼90 nm, we obtained values for the Young's modulus to be about 218 and 691 GPa, which are ofmore » the same order of magnitude as the values reported for bulk GaN. We also discuss the role of residual strain in the nanowire on the resonant frequency and the orientation dependence of the Young's modulus in wurtzite crystals.« less

  10. Mechanical Computing Redux: Limitations at the Nanoscale

    NASA Astrophysics Data System (ADS)

    Liu, Tsu-Jae King

    2014-03-01

    Technology solutions for overcoming the energy efficiency limits of nanoscale complementary metal oxide semiconductor (CMOS) technology ultimately will be needed in order to address the growing issue of integrated-circuit chip power density. Off-state leakage current sets a fundamental lower limit in energy per operation for any voltage-level-based digital logic implemented with transistors (CMOS and beyond), which leads to practical limits for device density (i.e. cost) and operating frequency (i.e. system performance). Mechanical switches have zero off-state leakag and hence can overcome this fundamental limit. Contact adhesive force sets a lower limit for the switching energy of a mechanical switch, however, and also directly impacts its performance. This paper will review recent progress toward the development of nano-electro-mechanical relay technology and discuss remaining challenges for realizing the promise of mechanical computing for ultra-low-power computing. Supported by the Center for Energy Efficient Electronics Science (NSF Award 0939514).

  11. Impact of asymmetric martensite and austenite nucleation and growth behavior on the phase stability and hysteresis of freestanding shape-memory nanoparticles

    NASA Astrophysics Data System (ADS)

    Ko, Won-Seok; Grabowski, Blazej; Neugebauer, Jörg

    2018-03-01

    Martensitic transformations in nanoscaled shape-memory alloys exhibit characteristic features absent for the bulk counterparts. Detailed understanding is required for applications in micro- and nanoelectromechanical systems, and experimental limitations render atomistic simulation an important complementary approach. Using a recently developed, accurate potential we investigate the phase transformation in freestanding Ni-Ti shape-memory nanoparticles with molecular-dynamics simulations. The results confirm that the decrease in the transformation temperature with decreasing particle size is correlated with an overstabilization of the austenitic surface energy over the martensitic surface energy. However, a detailed atomistic analysis of the nucleation and growth behavior reveals an unexpected difference in the mechanisms determining the austenite finish and martensite start temperature. While the austenite finish temperature is directly affected by a contribution of the surface energy difference, the martensite start temperature is mostly affected by the transformation strain, contrary to general expectations. This insight not only explains the reduced transformation temperature but also the reduced thermal hysteresis in freestanding nanoparticles.

  12. Experimental methods of actuation, characterization and prototyping of hydrogels for bioMEMS/NEMS applications.

    PubMed

    Khaleque, T; Abu-Salih, S; Saunders, J R; Moussa, W

    2011-03-01

    As a member of the smart polymer material group, stimuli responsive hydrogels have achieved a wide range of applications in microfluidic devices, micro/nano bio and environmental sensors, biomechanics and drug delivery systems. To optimize the utilization of a hydrogel in various micro and nano applications it is essential to have a better understanding of its mechanical and electrical properties. This paper presents a review of the different techniques used to determine a hydrogel's mechanical properties, including tensile strength, compressive strength and shear modulus and the electrical properties including electrical conductivity and dielectric permittivity. Also explored the effect of various prototyping factors and the mechanisms by which these factors are used to alter the mechanical and electrical properties of a hydrogel. Finally, this review discusses a wide range of hydrogel fabrication techniques and methods used, to date, to actuate this family of smart polymer material.

  13. How Small is too Small True Microrobots and Nanorobots for Military Applications in 2035

    DTIC Science & Technology

    2010-04-01

    field effect transistor or diode junction based.41 Additionally, NEMS sensors based on resonating thin films and nanowires42 and optical based...acoustic sensor is fabricated from piezoelectric thin films and measures 600 µm by 600 µm by 2.2 µm thick with a total volume of 0.0008 mm3.50 Since...microrobot systems by 2035. Reduction in thin film width dimensions (under 600 µm), in order to be able to physically incorporate this into a

  14. Frequency and amplitude stabilization in MEMS and NEMS oscillators

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chen, Changyao; Lopez, Omar Daniel; Czaplewski, David A.

    This invention comprises a nonlinear micro- and nano-mechanical resonator that can maintain frequency of operation and amplitude of operation for a period of time after all external power has been removed from the device. Utilizing specific nonlinear dynamics of the micromechanical resonator, mechanical energy at low frequencies can be input and stored in higher frequencies modes, thus using the multiple degrees of freedom of the resonator to extend its energy storage capacity. Furthermore, the energy stored in multiple vibrational modes can be used to maintain the resonator oscillating for a fixed period of time, even without an external power supply.more » This is the first demonstration of an "autonomous" frequency source that can maintain a constant frequency and vibrating amplitude when no external power is provided, making it ideal for applications requiring an oscillator in low power, or limited and intermittent power supplies.« less

  15. Application of nanomaterials in two-terminal resistive-switching memory devices

    PubMed Central

    Ouyang, Jianyong

    2010-01-01

    Nanometer materials have been attracting strong attention due to their interesting structure and properties. Many important practical applications have been demonstrated for nanometer materials based on their unique properties. This article provides a review on the fabrication, electrical characterization, and memory application of two-terminal resistive-switching devices using nanomaterials as the active components, including metal and semiconductor nanoparticles (NPs), nanotubes, nanowires, and graphenes. There are mainly two types of device architectures for the two-terminal devices with NPs. One has a triple-layer structure with a metal film sandwiched between two organic semiconductor layers, and the other has a single polymer film blended with NPs. These devices can be electrically switched between two states with significant different resistances, i.e. the ‘ON’ and ‘OFF’ states. These render the devices important application as two-terminal non-volatile memory devices. The electrical behavior of these devices can be affected by the materials in the active layer and the electrodes. Though the mechanism for the electrical switches has been in argument, it is generally believed that the resistive switches are related to charge storage on the NPs. Resistive switches were also observed on crossbars formed by nanotubes, nanowires, and graphene ribbons. The resistive switches are due to nanoelectromechanical behavior of the materials. The Coulombic interaction of transient charges on the nanomaterials affects the configurable gap of the crossbars, which results into significant change in current through the crossbars. These nanoelectromechanical devices can be used as fast-response and high-density memory devices as well. PMID:22110862

  16. Micro and Nano Electromechanical Systems for Near-Zero Power Infrared Detection

    NASA Astrophysics Data System (ADS)

    Qian, Zhenyun

    Light is one of the most important tools for human beings to probe and sense the physical world. Infrared (IR) radiation located in longer wavelengths than those of visible light carries rich information of an environment as it reveals the temperature distribution and chemical composition of objects. In addition, it has been utilized for communication and distance measurement owing to the atmospheric window and insensitiveness of human eyes to the IR radiation. As a result, IR detectors nowadays can be found in a wide variety of applications, including thermal imaging, automotive night vision, standoff chemical detection, remote control and laser ranging, just to mention a few. On the other hand, due to the recent fast development of the Internet of Things (IoT), there is a growing demand for miniaturized and power efficient unattended sensors that can be widely distributed in large volumes to form a wireless sensor networks capable of monitoring the environment with high accuracy and long lifetime. In this context, micro and nano electromechanical systems (MEMS/NEMS) may provide a huge impact, since they can be used for the implementation of miniaturized, low power, high-performance sensors and wireless communication devices fully compatible with standard integrated circuitry. This dissertation presents the design and the experimental verification of high performance uncooled IR detectors based on Aluminum Nitride (AlN) nano electromechanical resonators, and a first-of-its-kind near-zero power IR digitizer based on plasmonically-enhanced micromechanical photoswitches. The unique advantages of the piezoelectric AlN thin film in terms of scaling in thickness and transduction efficiency are exploited by the first experimental demonstration of ultra-fast (thermal time constant, tau ˜ 80 mus) and high resolution (noise equivalent power, NEP ˜ 656 pW/Hz1/2) AlN NEMS resonant IR detectors with reduced pixel size comparable to the state-of-the-art microbolometers

  17. A New Family of Secreted Toxins in Pathogenic Neisseria Species

    PubMed Central

    Jamet, Anne; Jousset, Agnès B.; Euphrasie, Daniel; Mukorako, Paulette; Boucharlat, Alix; Ducousso, Alexia; Charbit, Alain; Nassif, Xavier

    2015-01-01

    The genus Neisseria includes both commensal and pathogenic species which are genetically closely related. However, only meningococcus and gonococcus are important human pathogens. Very few toxins are known to be secreted by pathogenic Neisseria species. Recently, toxins secreted via type V secretion system and belonging to the widespread family of contact-dependent inhibition (CDI) toxins have been described in numerous species including meningococcus. In this study, we analyzed loci containing the maf genes in N. meningitidis and N. gonorrhoeae and proposed a novel uniform nomenclature for maf genomic islands (MGIs). We demonstrated that mafB genes encode secreted polymorphic toxins and that genes immediately downstream of mafB encode a specific immunity protein (MafI). We focused on a MafB toxin found in meningococcal strain NEM8013 and characterized its EndoU ribonuclease activity. maf genes represent 2% of the genome of pathogenic Neisseria, and are virtually absent from non-pathogenic species, thus arguing for an important biological role. Indeed, we showed that overexpression of one of the four MafB toxins of strain NEM8013 provides an advantage in competition assays, suggesting a role of maf loci in niche adaptation. PMID:25569427

  18. Issues in midterm analysis and forecasting 1998

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    NONE

    1998-07-01

    Issues in Midterm Analysis and Forecasting 1998 (Issues) presents a series of nine papers covering topics in analysis and modeling that underlie the Annual Energy Outlook 1998 (AEO98), as well as other significant issues in midterm energy markets. AEO98, DOE/EIA-0383(98), published in December 1997, presents national forecasts of energy production, demand, imports, and prices through the year 2020 for five cases -- a reference case and four additional cases that assume higher and lower economic growth and higher and lower world oil prices than in the reference case. The forecasts were prepared by the Energy Information Administration (EIA), using EIA`smore » National Energy Modeling System (NEMS). The papers included in Issues describe underlying analyses for the projections in AEO98 and the forthcoming Annual Energy Outlook 1999 and for other products of EIA`s Office of Integrated Analysis and Forecasting. Their purpose is to provide public access to analytical work done in preparation for the midterm projections and other unpublished analyses. Specific topics were chosen for their relevance to current energy issues or to highlight modeling activities in NEMS. 59 figs., 44 tabs.« less

  19. Mechanisms of hyposmotic volume regulation in isolated nematocytes of the anthozoan Aiptasia diaphana.

    PubMed

    Marino, Angela; Morabito, Rossana; La Spada, Giuseppina; Adragna, Norma C; Lauf, Peter K

    2010-01-01

    The nature and role of potassium (K) and water transport mediating hyposmotically-induced regulatory volume decrease (RVD) were studied in nematocytes dissociated with 605 mM thiocyanate from acontia of the Anthozoan Aiptasia diaphana. Cell volume and hence RVD were calculated from the inverse ratios of the cross sectional areas of nematocytes (A/A(o)) measured before (A(o)) and after (A) challenge with 65% artificial sea water (ASW). To distinguish between K channels and K-Cl cotransport (KCC), external sodium (Na) and chloride (Cl) were replaced by K and nitrate (NO(3)), respectively. Inhibitors were added to identify K channels (barium, Ba), and putative kinase (N-ethylmaleimide, NEM) and phosphatase (okadaic acid, OA) regulation of KCC. In 65% NaCl ASW, nematocytes displayed a biphasic change in A/A(o), peaking within 4 min due to osmotic water entry and thereafter declining within 6 min due to RVD. Changing NaCl to KCl or NaNO(3) ASW did not affect the osmotic phase but attenuated RVD, consistent with K channel and KCC mechanisms. Ba (3 mM) inhibited RVD. NEM and OA, applied separately, inhibited the osmotic phase and muted RVD suggesting primary action on water transport (aquaporins). NEM and OA together reduced the peak A/A(o) ratio during the osmotic phase whereas RVD was inhibited when OA preceded NEM. Thus, both K channels and KCC partake in the nematocyte RVD, the extent of which is determined by functional thiols and dephosphorylation of putative aquaporins facilitating the preceding osmotic water shifts. Copyright 2010 S. Karger AG, Basel.

  20. Prospective inter-relationships between late adolescent personality and major depressive disorder in early adulthood.

    PubMed

    Wilson, S; DiRago, A C; Iacono, W G

    2014-02-01

    A well-established body of literature demonstrates concurrent associations between personality traits and major depressive disorder (MDD), but there have been relatively few investigations of their dynamic interplay over time. Prospective inter-relationships between late-adolescent personality and MDD in early adulthood were examined in a community sample of male and female twins from the Minnesota Twin Family Study (MTFS; n = 1252). Participants were classified into naturally occurring MDD groups based on the timing (adolescent versus adult onset) and course (chronic/recurrent versus remitting) of MDD. MDD diagnoses were assessed at ages 17, 20, 24 and 29 years, and personality traits [negative emotionality (NEM), positive emotionality (PEM) and constraint (CON)] were assessed at ages 17, 24 and 29 years. Multilevel modeling (MLM) analyses indicated that higher age-17 NEM was associated with the subsequent development of MDD, and any MDD, regardless of onset or course, was associated with higher NEM up to age 29. Moreover, the chronic/recurrent MDD groups failed to show the normative decrease in NEM from late adolescence to early adulthood. Lower age-17 PEM was also associated with the subsequent development of MDD but only among the chronic/recurrent MDD groups. Finally, the adolescent-onset MDD groups reported lower age-17 CON relative to the never-depressed and adult-onset MDD groups. Taken together, the results speak to the role of personality traits for conferring risk for the onset of MDD in late adolescence and early adulthood, in addition to the pernicious implications of chronic/recurrent MDD, particularly when it onsets during adolescence, for adaptive personality development.

  1. Cascade unlooping of a low-pitch helical spring under tension

    NASA Astrophysics Data System (ADS)

    Starostin, E. L.; van der Heijden, G. H. M.

    2009-06-01

    We study the force vs. extension behaviour of a helical spring made of a thin torsionally stiff anisotropic elastic rod. Our focus is on springs of very low helical pitch. For certain parameters of the problem such a spring is found not to unwind when pulled but rather to form hockles that pop out one by one and lead to a highly non-monotonic force-extension curve. Between abrupt loop pop-outs this curve is well described by the planar elastica whose relevant solutions are classified. Our results may be relevant for tightly coiled nanosprings in future micro- and nano(electro)mechanical devices.

  2. Reducing adhesion energy of micro-relay electrodes by ion beam synthesized oxide nanolayers

    DOE PAGES

    Saha, Bivas; Peschot, Alexis; Osoba, Benjamin; ...

    2017-03-09

    Reduction in the adhesion energy of contacting metal electrode surfaces in nano-electro-mechanical switches is crucial for operation with low hysteresis voltage. We demonstrate that by forming thin layers of metal-oxides on metals such as Ru and W, the adhesion energy can be reduced by up to a factor of ten. We employ a low-energy ion-beam synthesis technique and subsequent thermal annealing to form very thin layers (~2 nm) of metal-oxides (such as RuO 2 and WO x) on Ru and W metal surfaces and quantify the adhesion energy using an atomic force microscope with microspherical tips.

  3. The roles of nematodes in nitrogen and phosphorous availability, plant uptake and growth in organically amended soils

    NASA Astrophysics Data System (ADS)

    Gebremikael, Mesfin; Buchan, David; De Neve, Stefaan

    2017-04-01

    Several studies have shown that soil biota contributes significantly to the crucial ecosystem functions and services such as organic matter decomposition and nutrient cycling. The contribution of each group of soil organisms may vary depending primarily on their feeding behavior. The magnitude of the ecosystem services by the biota may also depend on the interactions amongst the soil biota groups and their surrounding environment, for instance, biochemical characteristics of the externally added organic material. However, only a few studies considered these interactions concurrently. Here, we investigated the effects of fauna-microbe-plant interactions on organic matter decomposition and nutrient cycling by applying different organic materials spanning a range of C:N ratios and presumed N availability. Nematodes were selected as model fauna because they are the most abundant soil metazoans that have a diversified feeding strategy and interact very intimately with microbes, other fauna, and plants. A series of incubation experiments were conducted in bare and planted microcosms under controlled conditions using fresh soil collected from an agricultural field and defaunated by gamma irradiation. In the first experiment without plants, the defaunated soil cores were either left unamended (UNA) or received lignin-rich low N compost (COI), N-rich compost (COV), fresh manure (MAN) or chopped clover (CLO). The entire free-living soil nematode community was extracted from unirradiated fresh soil and reinoculated into half of the soil cores that had been defaunated by gamma irradiation. Two treatments: with (+Nem) and without (-Nem) nematodes were compared for soil nitrogen and phosphorus availability, plant uptake, and PLFA signatures over time during a 105-days incubation. The same experimental setup was used to investigate further the CLO amendment in the presence of plants (rye grass was used as a model plant). Nematodes were extracted and assigned to feeding groups

  4. Atomistic aspects of ductile responses of cubic silicon carbide during nanometric cutting

    PubMed Central

    2011-01-01

    Cubic silicon carbide (SiC) is an extremely hard and brittle material having unique blend of material properties which makes it suitable candidate for microelectromechanical systems and nanoelectromechanical systems applications. Although, SiC can be machined in ductile regime at nanoscale through single-point diamond turning process, the root cause of the ductile response of SiC has not been understood yet which impedes significant exploitation of this ceramic material. In this paper, molecular dynamics simulation has been carried out to investigate the atomistic aspects of ductile response of SiC during nanometric cutting process. Simulation results show that cubic SiC undergoes sp3-sp2 order-disorder transition resulting in the formation of SiC-graphene-like substance with a growth rate dependent on the cutting conditions. The disorder transition of SiC causes the ductile response during its nanometric cutting operations. It was further found out that the continuous abrasive action between the diamond tool and SiC causes simultaneous sp3-sp2 order-disorder transition of diamond tool which results in graphitization of diamond and consequent tool wear. PMID:22078069

  5. "Extremely minimally invasive": recent advances in nanotechnology research and future applications in neurosurgery.

    PubMed

    Mattei, Tobias A; Rehman, Azeem A

    2015-01-01

    The term "nanotechnology" refers to the development of materials and devices that have been designed with specific properties at the nanometer scale (10(-9) m), usually being less than 100 nm in size. Recent advances in nanotechnology have promised to enable visualization and intervention at the subcellular level, and its incorporation to future medical therapeutics is expected to bring new avenues for molecular imaging, targeted drug delivery, and personalized interventions. Although the central nervous system presents unique challenges to the implementation of new therapeutic strategies involving nanotechnology (such as the heterogeneous molecular environment of different CNS regions, the existence of multiple processing centers with different cytoarchitecture, and the presence of the blood-brain barrier), numerous studies have demonstrated that the incorporation of nanotechnology resources into the armamentarium of neurosurgery may lead to breakthrough advances in the near future. In this article, the authors present a critical review on the current 'state-of-the-art' of basic research in nanotechnology with special attention to those issues which present the greatest potential to generate major therapeutic progresses in the neurosurgical field, including nanoelectromechanical systems, nano-scaffolds for neural regeneration, sutureless anastomosis, molecular imaging, targeted drug delivery, and theranostic strategies.

  6. Why self-catalyzed nanowires are most suitable for large-scale hierarchical integrated designs of nanowire nanoelectronics

    NASA Astrophysics Data System (ADS)

    Noor Mohammad, S.

    2011-10-01

    Nanowires are grown by a variety of mechanisms, including vapor-liquid-solid, vapor-quasiliquid-solid or vapor-quasisolid-solid, oxide-assisted growth, and self-catalytic growth (SCG) mechanisms. A critical analysis of the suitability of self-catalyzed nanowires, as compared to other nanowires, for next-generation technology development has been carried out. Basic causes of superiority of self-catalyzed (SCG) nanowires over other nanowires have been described. Polytypism in nanowires has been studied, and a model for polytypism has been proposed. The model predicts polytypism in good agreement with available experiments. This model, together with various evidences, demonstrates lower defects, dislocations, and stacking faults in SCG nanowires, as compared to those in other nanowires. Calculations of carrier mobility due to dislocation scattering, ionized impurity scattering, and acoustic phonon scattering explain the impact of defects, dislocations, and stacking faults on carrier transports in SCG and other nanowires. Analyses of growth mechanisms for nanowire growth directions indicate SCG nanowires to exhibit the most controlled growth directions. In-depth investigation uncovers the fundamental physics underlying the control of growth direction by the SCG mechanism. Self-organization of nanowires in large hierarchical arrays is crucial for ultra large-scale integration (ULSI). Unique features and advantages of self-organized SCG nanowires, unlike other nanowires, for this ULSI have been discussed. Investigations of nanowire dimension indicate self-catalyzed nanowires to have better control of dimension, higher stability, and higher probability, even for thinner structures. Theoretical calculations show that self-catalyzed nanowires, unlike catalyst-mediated nanowires, can have higher growth rate and lower growth temperature. Nanowire and nanotube characteristics have been found also to dictate the performance of nanoelectromechanical systems. Defects, such as

  7. Proteolytic activities in cortex of apical parts of Vicia faba ssp. minor seedling roots during kinetin-induced programmed cell death.

    PubMed

    Kaźmierczak, Andrzej; Doniak, Magdalena; Kunikowska, Anita

    2017-11-01

    Programmed cell death (PCD) is a crucial process in plant development. In this paper, proteolytically related aspects of kinetin-induced PCD in cortex cells of Vicia faba ssp. minor seedlings were examined using morphological, fluorometric, spectrophotometric, and fluorescence microscopic analyses. Cell viability estimation after 46 μM kinetin treatment of seedling roots showed that the number of dying cortex cells increased with treatment duration, reaching maximum after 72 h. Weight of the apical root segments increased with time and was about 2.5-fold greater after 96 h, while the protein content remained unchanged, compared to the control. The total and cysteine-dependent proteolytic activities fluctuated during 1-96-h treatment, which was not accompanied by the changes in the protein amount, indicating that the absolute protein amounts decreased during kinetin-induced PCD. N-ethylmaleimide (NEM), phenylmethylsulfonyl fluoride (PMSF), and Z-Leu-Leu-Nva-H (MG115), the respective cysteine, serine, and proteasome inhibitors, suppressed kinetin-induced PCD. PMSF significantly decreased serine-dependent proteolytic activities without changing the amount of proteins, unlike NEM and MG115. More pronounced effect of PMSF over NEM indicated that in the root apical segments, the most important proteolytic activity during kinetin-induced PCD was that of serine proteases, while that of cysteine proteases may be important for protein degradation in the last phase of the process. Both NEM and PMSF inhibited apoptotic-like structure formation during kinetin-induced PCD. The level of caspase-3-like activity of β1 proteasome subunit increased after kinetin treatment. Addition of proteasome inhibitor MG-115 reduced the number of dying cells, suggesting that proteasomes might play an important role during kinetin-induced PCD.

  8. A statistical model to predict total column ozone in Peninsular Malaysia

    NASA Astrophysics Data System (ADS)

    Tan, K. C.; Lim, H. S.; Mat Jafri, M. Z.

    2016-03-01

    This study aims to predict monthly columnar ozone in Peninsular Malaysia based on concentrations of several atmospheric gases. Data pertaining to five atmospheric gases (CO2, O3, CH4, NO2, and H2O vapor) were retrieved by satellite scanning imaging absorption spectrometry for atmospheric chartography from 2003 to 2008 and used to develop a model to predict columnar ozone in Peninsular Malaysia. Analyses of the northeast monsoon (NEM) and the southwest monsoon (SWM) seasons were conducted separately. Based on the Pearson correlation matrices, columnar ozone was negatively correlated with H2O vapor but positively correlated with CO2 and NO2 during both the NEM and SWM seasons from 2003 to 2008. This result was expected because NO2 is a precursor of ozone. Therefore, an increase in columnar ozone concentration is associated with an increase in NO2 but a decrease in H2O vapor. In the NEM season, columnar ozone was negatively correlated with H2O (-0.847), NO2 (0.754), and CO2 (0.477); columnar ozone was also negatively but weakly correlated with CH4 (-0.035). In the SWM season, columnar ozone was highly positively correlated with NO2 (0.855), CO2 (0.572), and CH4 (0.321) and also highly negatively correlated with H2O (-0.832). Both multiple regression and principal component analyses were used to predict the columnar ozone value in Peninsular Malaysia. We obtained the best-fitting regression equations for the columnar ozone data using four independent variables. Our results show approximately the same R value (≈ 0.83) for both the NEM and SWM seasons.

  9. Comparing nutrition environments in bodegas and fast food restaurants

    PubMed Central

    Lovasi, Laszlo; Yousefzadeh, Paulette; Sheehan, Daniel; Milinkovic, Karla; Baecker, Aileen; Bader, Michael D. M.; Weiss, Christopher; Lovasi, Gina S.; Rundle, Andrew

    2015-01-01

    Many small grocery stores or “bodegas” sell prepared or ready-to-eat items, filling a similar niche in the food environment as fast food restaurants. However, little comparative information is available about the nutrition environments of bodegas and fast food outlets. This study compared the nutrition environments of bodegas and national chain fast food restaurants using a common audit instrument, the Nutrition Environment Measures Study in Restaurants (NEMS-R) protocol. The analytic sample included 109 bodegas and 107 fast food restaurants located in New York City neighborhoods in the upper third and lower third of the census tract poverty rate distribution. Inter-rater reliability was evaluated in 102 food outlets including 31 from the analytic sample and 71 from a supplementary convenience sample. The analysis compared scores on individual NEMS-R items, a total summary score, and sub-scores indicating healthy food availability, nutrition information, promotions of healthy or unhealthy eating, and price incentives for healthy eating, using t-tests and chi-square statistics to evaluate differences by outlet type and neighborhood poverty. Fast food restaurants were more likely to provide nutritional information, while bodegas scored higher on healthy food availability, promotions, and pricing. Bodegas and fast food restaurants had similar NEMS-R total scores (bodegas: 13.09, fast food: 14.31, p=0.22). NEMS-R total scores were higher (indicating healthier environments) in low- than high-poverty neighborhoods among both bodegas (14.79 vs. 11.54, p=0.01) and fast food restaurants (16.27 vs. 11.60, p<.01). Results imply different policy measures to improve nutrition environments in the two types of food outlets. PMID:24035459

  10. Nucleotide-protectable labeling of sulfhydryl groups in subunit I of the ATPase from Halobacterium saccharovorum

    NASA Technical Reports Server (NTRS)

    Sulzner, Michael; Stan-Lotter, Helga; Hochstein, Lawrence I.

    1992-01-01

    The membrane ATPase from Halobacterium saccharovorum was purified as described by Hochstein et al. (1987) and was incubated with C-14 labeled N-ethylmaleimide (NEM), with and without adenine nucleotides, to determine the effect of nucleotides on the enzyme labeling. It was found that NEM incorporates into the 87,000-Da subunit (subunit I) of the enzyme and that the conditions for enzyme modification are similar to those which result in the inhibition of the enzyme activity. The presence of ATP, ADP, and AMP was found to reduce both the inhibitor incorporation and enzyme inhibition. It was shown that the reaction involves a modification of thiol groups.

  11. CONHECIMENTO DA LEI GERAL DE SAÚDE – RESPEITO ÀS TRANSFUSÕES SANGUÍNEAS EM MÉDICOS E PACIENTES TESTEMUNHAS DE JEOVÁ DO HOSPITAL DR. DARÍO CONTRERAS DA REPÚBLICA DOMINICANA

    PubMed Central

    SANTANA, ELSA DÍAZ

    2010-01-01

    Este estudo avalia quanto o corpo médico do Hospital Dr. Darío Contreras de República Dominicana conhece, respeita, informa e aplica a Lei Geral de Saúde em relação aos direitos do paciente Testemunha de Jeová de negar-se a ser transfundido (respeito a sua autonomia); também se os Testemunhas de Jeová conhecem a Lei Geral de Saúde e até que ponto têm se beneficiado diante dessa proposição. O estudo revelou que nem médicos, nem Testemunhas de Jeová conhecem de fato essa lei. PMID:20689657

  12. Improved resonance characteristics of GaAs beam resonators by epitaxially induced strain

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yamaguchi, H.; Onomitsu, K.; Kato, K.

    2008-06-23

    Micromechanical-beam resonators were fabricated using a strained GaAs film grown on relaxed In{sub 0.1}Ga{sub 0.9}As/In{sub 0.1}Al{sub 0.9}As buffer layers. The natural frequency of the fundamental mode was increased 2.5-4 times by applying tensile strain, showing good agreement with the model calculation assuming strain of 0.35% along the beam. In addition, the Q factor of 19 000 was obtained for the best sample, which is one order of magnitude higher than that for the unstrained resonator. This technique can be widely applied for improving the performance of resonator-based micro-/nanoelectromechanical devices.

  13. Macro-mechanics controls quantum mechanics: mechanically controllable quantum conductance switching of an electrochemically fabricated atomic-scale point contact.

    PubMed

    Staiger, Torben; Wertz, Florian; Xie, Fangqing; Heinze, Marcel; Schmieder, Philipp; Lutzweiler, Christian; Schimmel, Thomas

    2018-01-12

    Here, we present a silver atomic-scale device fabricated and operated by a combined technique of electrochemical control (EC) and mechanically controllable break junction (MCBJ). With this EC-MCBJ technique, we can perform mechanically controllable bistable quantum conductance switching of a silver quantum point contact (QPC) in an electrochemical environment at room temperature. Furthermore, the silver QPC of the device can be controlled both mechanically and electrochemically, and the operating mode can be changed from 'electrochemical' to 'mechanical', which expands the operating mode for controlling QPCs. These experimental results offer the perspective that a silver QPC may be used as a contact for a nanoelectromechanical relay.

  14. Macro-mechanics controls quantum mechanics: mechanically controllable quantum conductance switching of an electrochemically fabricated atomic-scale point contact

    NASA Astrophysics Data System (ADS)

    Staiger, Torben; Wertz, Florian; Xie, Fangqing; Heinze, Marcel; Schmieder, Philipp; Lutzweiler, Christian; Schimmel, Thomas

    2018-01-01

    Here, we present a silver atomic-scale device fabricated and operated by a combined technique of electrochemical control (EC) and mechanically controllable break junction (MCBJ). With this EC-MCBJ technique, we can perform mechanically controllable bistable quantum conductance switching of a silver quantum point contact (QPC) in an electrochemical environment at room temperature. Furthermore, the silver QPC of the device can be controlled both mechanically and electrochemically, and the operating mode can be changed from ‘electrochemical’ to ‘mechanical’, which expands the operating mode for controlling QPCs. These experimental results offer the perspective that a silver QPC may be used as a contact for a nanoelectromechanical relay.

  15. Dynamic control of the asymmetric Fano resonance in side-coupled Fabry–Pérot and photonic crystal nanobeam cavities

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lin, Tong; Chau, Fook Siong; Zhou, Guangya, E-mail: mpezgy@nus.edu.sg

    2015-11-30

    Fano resonance is a prevailing interference phenomenon that stems from the intersection between discrete and continuum states in many fields. We theoretically and experimentally characterize the asymmetric Fano lineshape in side-coupled waveguide Fabry–Pérot and photonic crystal nanobeam cavities. The measured quality-factor of the Fano resonance before tuning is 28 100. A nanoelectromechanical systems bidirectional actuator is integrated seamlessly to control the shape of the Fano resonance through in-plane translations in two directions without sacrificing the quality-factor. The peak intensity level of the Fano resonance can be increased by 8.5 dB from 60 nW to 409 nW while the corresponding dip intensity ismore » increased by 12.8 dB from 1 nW to 18 nW. The maximum recorded quality-factor throughout the tuning procedure is up to 32 500. Potential applications of the proposed structure include enhancing the sensitivity of sensing, reconfigurable nanophotonics devices, and on-chip intensity modulator.« less

  16. Mechanical Modulation of Tunneling Current in Transition Metal Dichalcogenides Heterostructures: A First Principles Study

    NASA Astrophysics Data System (ADS)

    Kuroda, Marcelo

    Recent experiments in MoS2 heterostructures reported that out-of-plane tunneling piezoresistivity (TPR) - mechanical modulation of the tunneling current - achieves sensitivities of one decade per Ådisplacement. Owing to their nanometer scale, a quantitative theoretical framework providing the TPR structure-property relationship is necessary to further improve sensitivities. To this end, first principles calculations within density functional theory are used to characterize the phenomenon in MoX2 (with X = S, Se). The TPR is quantified in relation to electrode composition and film thickness showing remarkable agreement with experiments. The origin of the TPR is attributed to the heterostructure compliance rather than band alignment changes with strain, and differs from mechanisms in other nanometer-thick bulk films. Large work function metals (Pt, Au) are singled out as best candidates for enhanced TPR gauges due to weak bonding and negligible thermionic emission; compliant bilayers show larger stress-sensitivity than monolayers. By accounting for the atomistic details and material composition of 2D material-based heterostructures, this work has the potential to advance sensor and nano-electro-mechanical system technologies.

  17. Single-crystal diamond nanomechanical resonators with quality factors exceeding one million

    NASA Astrophysics Data System (ADS)

    Tao, Y.; Boss, J. M.; Moores, B. A.; Degen, C. L.

    2014-04-01

    Diamond has gained a reputation as a uniquely versatile material, yet one that is intricate to grow and process. Resonating nanostructures made of single-crystal diamond are expected to possess excellent mechanical properties, including high-quality factors and low dissipation. Here we demonstrate batch fabrication and mechanical measurements of single-crystal diamond cantilevers with thickness down to 85 nm, thickness uniformity better than 20 nm and lateral dimensions up to 240 μm. Quality factors exceeding one million are found at room temperature, surpassing those of state-of-the-art single-crystal silicon cantilevers of similar dimensions by roughly an order of magnitude. The corresponding thermal force noise for the best cantilevers is ~5·10-19 N Hz-1/2 at millikelvin temperatures. Single-crystal diamond could thus directly improve existing force and mass sensors by a simple substitution of resonator material. Presented methods are easily adapted for fabrication of nanoelectromechanical systems, optomechanical resonators or nanophotonic devices that may lead to new applications in classical and quantum science.

  18. Molecular dynamics simulation of square graphene-nanoflake oscillator on graphene nanoribbon.

    PubMed

    Kang, Jeong Won; Lee, Kang Whan

    2014-12-01

    Graphene nanoflakes (GNFs) have been of interest for a building block in order to develop electromechanical devices on a nanometer scale. Here, we present the oscillation motions of a square GNF oscillator on graphene nanoribbon (GNR) in the retracting-motions by performing classical molecular dynamics simulations. The simulation results showed that the GNF oscillators can be considered as a building block for nanoelectromechanical systems such as carbon-nanotube (CNT) oscillators. The oscillation dynamics of the GNF oscillator were similar to those of the CNT oscillators. When the square GNF had an initial velocity as impulse dynamics, its oscillation motions on the GNR were achieved from its self-retracting van der Waals force. For low initial velocity, its translational motions were dominant in its motions rather than its rotational motions. The kinetic energy damping ratio rapidly decreased as initial velocity increased and the kinetic energy for the translational motion of the GNF oscillator rapidly transferred into that for its rotational motion. The oscillation frequency of the GNF oscillator was dependent on its initial velocity.

  19. Characterization of microcracks by application of digital image correlation to SPM images

    NASA Astrophysics Data System (ADS)

    Keller, Juergen; Gollhardt, Astrid; Vogel, Dietmar; Michel, Bernd

    2004-07-01

    With the development of micro- and nanotechnological products such as sensors, MEMS/NEMS and their broad application in a variety of market segments new reliability issues will arise. The increasing interface-to-volume ratio in highly integrated systems and nanoparticle filled materials and unsolved questions of size effect of nanomaterials are challenges for experimental reliability evaluation. To fulfill this needs the authors developed the nanoDAC method (nano Deformation Analysis by Correlation), which allows the determination and evaluation of 2D displacement fields based on scanning probe microscopy (SPM) data. In-situ SPM scans of the analyzed object are carried out at different thermo-mechanical load states. The obtained topography-, phase- or error-images are compared utilizing grayscale cross correlation algorithms. This allows the tracking of local image patterns of the analyzed surface structure. The measurement results of the nanoDAC method are full-field displacement and strain fields. Due to the application of SPM equipment deformations in the micro-, nanometer range can be easily detected. The method can be performed on bulk materials, thin films and on devices i.e microelectronic components, sensors or MEMS/NEMS. Furthermore, the characterization and evaluation of micro- and nanocracks or defects in bulk materials, thin layers and at material interfaces can be carried out.

  20. A large change in temperature between neighbouring days increases the risk of mortality.

    PubMed

    Guo, Yuming; Barnett, Adrian G; Yu, Weiwei; Pan, Xiaochuan; Ye, Xiaofang; Huang, Cunrui; Tong, Shilu

    2011-02-02

    Previous studies have found high temperatures increase the risk of mortality in summer. However, little is known about whether a sharp decrease or increase in temperature between neighbouring days has any effect on mortality. Poisson regression models were used to estimate the association between temperature change and mortality in summer in Brisbane, Australia during 1996-2004 and Los Angeles, United States during 1987-2000. The temperature change was calculated as the current day's mean temperature minus the previous day's mean. In Brisbane, a drop of more than 3 °C in temperature between days was associated with relative risks (RRs) of 1.157 (95% confidence interval (CI): 1.024, 1.307) for total non-external mortality (NEM), 1.186 (95%CI: 1.002, 1.405) for NEM in females, and 1.442 (95%CI: 1.099, 1.892) for people aged 65-74 years. An increase of more than 3 °C was associated with RRs of 1.353 (95%CI: 1.033, 1.772) for cardiovascular mortality and 1.667 (95%CI: 1.146, 2.425) for people aged <65 years. In Los Angeles, only a drop of more than 3 °C was significantly associated with RRs of 1.133 (95%CI: 1.053, 1.219) for total NEM, 1.252 (95%CI: 1.131, 1.386) for cardiovascular mortality, and 1.254 (95%CI: 1.135, 1.385) for people aged ≥ 75 years. In both cities, there were joint effects of temperature change and mean temperature on NEM. A significant change in temperature of more than 3 °C, whether positive or negative, has an adverse impact on mortality even after controlling for the current temperature.

  1. Comparing nutrition environments in bodegas and fast-food restaurants.

    PubMed

    Neckerman, Kathryn M; Lovasi, Laszlo; Yousefzadeh, Paulette; Sheehan, Daniel; Milinkovic, Karla; Baecker, Aileen; Bader, Michael D M; Weiss, Christopher; Lovasi, Gina S; Rundle, Andrew

    2014-04-01

    Many small grocery stores or "bodegas" sell prepared or ready-to-eat items, filling a niche in the food environment similar to fast-food restaurants. However, little comparative information is available about the nutrition environments of bodegas and fast-food outlets. This study compared the nutrition environments of bodegas and national chain fast-food restaurants using a common audit instrument, the Nutrition Environment Measures Study in Restaurants (NEMS-R) protocol. The analytic sample included 109 bodegas and 107 fast-food restaurants located in New York City neighborhoods in the upper third and lower third of the census tract poverty rate distribution. Inter-rater reliability was evaluated in 102 food outlets, including 31 from the analytic sample and 71 from a supplementary convenience sample. The analysis compared scores on individual NEMS-R items, a total summary score, and subscores indicating healthy food availability, nutrition information, promotions of healthy or unhealthy eating, and price incentives for healthy eating, using t tests and χ(2) statistics to evaluate differences by outlet type and neighborhood poverty. Fast-food restaurants were more likely to provide nutrition information, and bodegas scored higher on healthy food availability, promotions, and pricing. Bodegas and fast-food restaurants had similar NEMS-R total scores (bodegas 13.09, fast food 14.31; P=0.22). NEMS-R total scores were higher (indicating healthier environments) in low- than high-poverty neighborhoods among both bodegas (14.79 vs 11.54; P=0.01) and fast-food restaurants (16.27 vs 11.60; P<0.01). Results imply different policy measures to improve nutrition environments in the two types of food outlets. Copyright © 2014 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

  2. Regulation of potassium transport in human lens epithelial cells.

    PubMed

    Lauf, Peter K; Warwar, Ronald; Brown, Thomas L; Adragna, Norma C

    2006-01-01

    The major K influx pathways and their response to thiol modification by N-ethylmaleimide (NEM) and protein kinase and phosphatase inhibitors were characterized in human lens epithelial B3 (HLE-B3) cells with Rb as K congener. Ouabain (0.1 mM) and bumetanide (5 microM) discriminated between the Na/K pump ( approximately 35% of total Rb influx) and Na-K-2Cl cotransport (NKCC) ( approximately 50%). Cl-replacement with nitrate or sulfamate revealed <10% residual [ouabain+bumetanide]-insensitive K-Cl cotransport (KCC). At 0.3-0.5 mM, NEM stimulated the Na/K pump by 2-fold independent of external Na, KCC between 2 and 4-fold, and abolished approximately 90% of NKCC. Calyculin-A, a serine/threonine protein phosphatase-1 inhibitor, did not affect NKCC but inhibited KCC, whereas 10 microM staurosporine, a serine/threonine kinase inhibitor, abolished NKCC, and stimulated KCC only when followed by NEM treatment. The tyrosine-kinase inhibitor genistein, at concentrations >100 microM, activated the Na/K pump and abolished NKCC but did not affect KCC. The data suggest at least partial inverse regulation of KCC and NKCC in HLE-B3 cells by signaling cascades involving serine, threonine and tyrosine phosphorylation/dephosphorylation equilibria.

  3. Differential effects of methylmethane thiosulfonate on rat liver GPAT and DHAPAT

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Webber, K.O.; Carter, B.D.; Datta, N.D.

    Subcellular fractions (mitochondrial (M), light-mitochondrial (L), and microsomal) from rat liver were treated with 5 mM methylmethane thiosulfonate (MMTS) or 50 ..mu..M N-ethylmaleimide (NEM). Both of these reagents are known to specifically modify cysteine residues in proteins. After treatment, samples of each fraction were assayed for glycerophosphate acyltransferase and dihydroxyacetone phosphate acyltransferase activities. As reported by others, NEM was found to inhibit GPAT in the microsomal fraction but had no effect on this enzyme in the M or L fractions. MMTS, on the other hand, inhibited GPAT in all fractions to the extent of 80-100% compared to activity in untreatedmore » samples. DHAPAT activity in each fraction showed little or no inhibition by either reagent. Only the microsomal DHAPAT activity showed any sensitivity at all, being inhibited by 10-12% by both NEM and MMTS. This is the first demonstration of inhibition of mitochondrial GPAT by a thiol-specific reagent and is an indication that, like the microsomal analog, this enzyme may have a cysteine residue at or near the active site. In addition, these results are further evidence for the premise that DHAPAT and GPAT are separate and distinct proteins.« less

  4. Probing nanocrystalline grain dynamics in nanodevices

    PubMed Central

    Yeh, Sheng-Shiuan; Chang, Wen-Yao; Lin, Juhn-Jong

    2017-01-01

    Dynamical structural defects exist naturally in a wide variety of solids. They fluctuate temporally and hence can deteriorate the performance of many electronic devices. Thus far, the entities of these dynamic objects have been identified to be individual atoms. On the other hand, it is a long-standing question whether a nanocrystalline grain constituted of a large number of atoms can switch, as a whole, reversibly like a dynamical atomic defect (that is, a two-level system). This is an emergent issue considering the current development of nanodevices with ultralow electrical noise, qubits with long quantum coherence time, and nanoelectromechanical system sensors with ultrahigh resolution. We demonstrate experimental observations of dynamic nanocrystalline grains that repeatedly switch between two or more metastable coordinate states. We study temporal resistance fluctuations in thin ruthenium dioxide (RuO2) metal nanowires and extract microscopic parameters, including relaxation time scales, mobile grain sizes, and the bonding strengths of nanograin boundaries. These material parameters are not obtainable by other experimental approaches. When combined with previous in situ high-resolution transmission electron microscopy, our electrical method can be used to infer rich information about the structural dynamics of a wide variety of nanodevices and new two-dimensional materials. PMID:28691094

  5. Atomic force microscopy for two-dimensional materials: A tutorial review

    NASA Astrophysics Data System (ADS)

    Zhang, Hang; Huang, Junxiang; Wang, Yongwei; Liu, Rui; Huai, Xiulan; Jiang, Jingjing; Anfuso, Chantelle

    2018-01-01

    Low dimensional materials exhibit distinct properties compared to their bulk counterparts. A plethora of examples have been demonstrated in two-dimensional (2-D) materials, including graphene and transition metal dichalcogenides (TMDCs). These novel and intriguing properties at the nano-, molecular- and even monatomic scales have triggered tremendous interest and research, from fundamental studies to practical applications and even device fabrication. The unique behaviors of 2-D materials result from the special structure-property relationships that exist between surface topographical variations and mechanical responses, electronic structures, optical characteristics, and electrochemical properties. These relationships are generally convoluted and sensitive to ambient and external perturbations. Characterizing these systems thus requires techniques capable of providing multidimensional information under controlled environments, such as atomic force microscopy (AFM). Today, AFM plays a key role in exploring the basic principles underlying the functionality of 2-D materials. In this tutorial review, we provide a brief introduction to some of the unique properties of 2-D materials, followed by a summary of the basic principles of AFM and the various AFM modes most appropriate for studying these systems. Following that, we will focus on five important properties of 2-D materials and their characterization in more detail, including recent literature examples. These properties include nanomechanics, nanoelectromechanics, nanoelectrics, nanospectroscopy, and nanoelectrochemistry.

  6. Buckling Behavior of Substrate Supported Graphene Sheets

    PubMed Central

    Yang, Kuijian; Chen, Yuli; Pan, Fei; Wang, Shengtao; Ma, Yong; Liu, Qijun

    2016-01-01

    The buckling of graphene sheets on substrates can significantly degrade their performance in materials and devices. Therefore, a systematic investigation on the buckling behavior of monolayer graphene sheet/substrate systems is carried out in this paper by both molecular mechanics simulations and theoretical analysis. From 70 simulation cases of simple-supported graphene sheets with different sizes under uniaxial compression, two different buckling modes are investigated and revealed to be dominated by the graphene size. Especially, for graphene sheets with length larger than 3 nm and width larger than 1.1 nm, the buckling mode depends only on the length/width ratio. Besides, it is revealed that the existence of graphene substrate can increase the critical buckling stress and strain to 4.39 N/m and 1.58%, respectively, which are about 10 times those for free-standing graphene sheets. Moreover, for graphene sheets with common size (longer than 20 nm), both theoretical and simulation results show that the critical buckling stress and strain are dominated only by the adhesive interactions with substrate and independent of the graphene size. Results in this work provide valuable insight and guidelines for the design and application of graphene-derived materials and nano-electromechanical systems. PMID:28787831

  7. The piezoelectric gating effect in a thin bent membrane with a two-dimensional electron gas

    NASA Astrophysics Data System (ADS)

    Shevyrin, Andrey A.; Pogosov, Arthur G.

    2018-05-01

    Thin suspended nanostructures with a two-dimensional electron gas can be used as nanoelectromechanical systems in which electron transport is piezoelectrically coupled to mechanical motion and vibrations. Apart from practical applications, these systems are interesting for studying electron transport under unusual conditions, namely, in the presence of additional mechanical degrees of freedom. In the present paper, we analyze the influence of the bending on the density of a gated two-dimensional electron gas contained in a suspended membrane using the Thomas–Fermi approach and the model of pure electrostatic screening. We show that a small bending is analogous to a small change in gate voltages. Our calculations demonstrate that the density change is most prominent near the edges of the conductive channel created by negatively biased gates. When moving away from these edges, the bending-induced density change rapidly decays. We propose several methods to increase the magnitude of the effect, with the largest benefit obtained from coverage of the conductive channel with an additional grounded gate. It is shown that, for a conductive channel under a bare surface, the largest effect can be achieved if the two-dimensional electron gas is placed near the middle of the membrane thickness, despite the bending-induced strain is zero there.

  8. Viscous cavity damping of a microlever in a simple fluid.

    PubMed

    Siria, A; Drezet, A; Marchi, F; Comin, F; Huant, S; Chevrier, J

    2009-06-26

    We consider the problem of oscillation damping in air of a thermally actuated microlever as it gradually approaches an infinite wall in parallel geometry. As the gap is decreased from 20 microm down to 400 nm, we observe the increasing damping of the lever Brownian motion in the fluid laminar regime. This manifests itself as a linear decrease in the lever quality factor accompanied by a dramatic softening of its resonance, and eventually leads to the freezing of the CL oscillation. We are able to quantitatively explain this behavior by analytically solving the Navier-Stokes equation with perfect slip boundary conditions. Our findings may have implications for microfluidics and micro- and nanoelectromechanical applications.

  9. Personality trait change across late childhood to young adulthood: Evidence for nonlinearity and sex differences in change.

    PubMed

    Durbin, C Emily; Hicks, Brian M; Blonigen, Daniel M; Johnson, Wendy; Iacono, William G; McGue, Matt

    2016-01-01

    We explored patterns of self-reported personality trait change across late childhood through young adulthood in a sample assessed up to 4 times on the lower-order facets of Positive Emotionality (PEM), Negative Emotionality (NEM), and Constraint (CON). Multilevel modeling analyses were used to describe both group- and individual-level change trajectories across this time span. There was evidence for nonlinear age-related change in most traits, and substantial individual differences in change for all traits. Gender differences were detected in the change trajectories for several facets of NEM and CON. Findings add to the literature on personality development by demonstrating robust nonlinear change in several traits across late childhood to young adulthood, as well as deviations from normative patterns of maturation at the earliest ages.

  10. Energy requirements for growth of pubertal female Saanen goats.

    PubMed

    Figueiredo, F O M; Berchielli, T T; Resende, K T; Gomes, H F B; Almeida, A K; Sakomura, N K; Teixeira, I A M A

    2016-04-01

    Previous research on energy requirements of female Saanen goats, using the factorial approach, has not considered the specific requirements for maintenance and growth during the pubertal phase. Thus, the purpose of this study was to estimate energy requirements for maintenance (Trial 1) and growth (Trial 2) of non-pregnant and non-lactating female Saanen goats at the pubertal phase from 30 to 45 kg. In Trial 1, the net energy requirements for maintenance (NEm ) were estimated using 18 female Saanen goats randomly assigned to three levels of intake: ad libitum, and 70% and 40% of ad libitum intake. These animals were pair-fed in six slaughter groups, each consisting of one animal for each level of intake. In Trial 2, the net energy requirements for growth (NEg ) were estimated using 18 female Saanen goats, which were fed ad libitum and slaughtered at targeted BW of 30, 38 and 45 kg. The NEm was 52 kcal/kg(0.75) of BW. The NEg increased from 3.5 to 4.7 Mcal/kg of BW gain as BW increased from 30 to 45 kg. Our results suggest that the guidelines of the major feeding systems for the entire growth phase may not be adequate for females at pubertal phase. Journal of Animal Physiology and Animal Nutrition © 2015 Blackwell Verlag GmbH.

  11. Medicine prices, availability, and affordability in the Shaanxi Province in China: implications for the future.

    PubMed

    Jiang, Minghuan; Zhou, Zhongliang; Wu, Lina; Shen, Qian; Lv, Bing; Wang, Xiao; Yang, Shimin; Fang, Yu

    2015-02-01

    In 2009, China implemented the National Essential Medicines System (NEMS) to improve access to high-quality low-cost essential medicines. To measure the prices, availability and affordability of medicines in China following the implementation of the NEMS. 120 public hospitals and 120 private pharmacies in ten cities in Shaanxi Province, Western China. The standardized methodology developed by the World Health Organization and Health Action International was used to collect data on prices and availability of 49 medicines. Median price ratio; availability as a percentage; cost of course of treatment in days' wages of the lowest-paid government workers. In the public hospitals, originator brands (OBs) were procured at 8.89 times the international reference price, more than seven times higher than the lowest-priced generics (LPGs). Patients paid 11.83 and 1.69 times the international reference prices for OBs and generics respectively. A similar result was observed in the private pharmacies. The mean availabilities of OBs and LPGs were 7.1 and 20.0 % in the public hospitals, and 12.6 and 29.2 % in the private pharmacies. Treatment with OBs is therefore largely unaffordable, but the affordability of the LPGs is generally good. High prices and low availability of survey medicines were observed. The affordability of generics, but not OBs, is reasonable. Effective measures should be taken to reduce medicine prices and improve availability and affordability in Shaanxi Province.

  12. On the Path to SunShot - Utility Regulatory Business Model Reforms forAddressing the Financial Impacts of Distributed Solar on Utilities

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    None, None

    Net-energy metering (NEM) with volumetric retail electricity pricing has enabled rapid proliferation of distributed photovoltaics (DPV) in the United States. However, this transformation is raising concerns about the potential for higher electricity rates and cost-shifting to non-solar customers, reduced utility shareholder profitability, reduced utility earnings opportunities, and inefficient resource allocation. Although DPV deployment in most utility territories remains too low to produce significant impacts, these concerns have motivated real and proposed reforms to utility regulatory and business models, with profound implications for future DPV deployment. This report explores the challenges and opportunities associated with such reforms in the context ofmore » the U.S. Department of Energy’s SunShot Initiative. As such, the report focuses on a subset of a broader range of reforms underway in the electric utility sector. Drawing on original analysis and existing literature, we analyze the significance of DPV’s financial impacts on utilities and non-solar ratepayers under current NEM rules and rate designs, the projected effects of proposed NEM and rate reforms on DPV deployment, and alternative reforms that could address utility and ratepayer concerns while supporting continued DPV growth. We categorize reforms into one or more of four conceptual strategies. Understanding how specific reforms map onto these general strategies can help decision makers identify and prioritize options for addressing specific DPV concerns that balance stakeholder interests.« less

  13. Formative Evaluation for a Healthy Corner Store Initiative in Pitt County, North Carolina: Assessing the Rural Food Environment, Part 1

    PubMed Central

    Bringolf, Karamie R.; Lawton, Katherine K.; McGuirt, Jared T.; Wall-Bassett, Elizabeth; Morgan, Jo; Laska, Melissa Nelson; Sharkey, Joseph R.

    2013-01-01

    Introduction Obesity prevalence in the rural United States is higher than in urban or suburban areas, perhaps as a result of the food environment. Because rural residents live farther from supermarkets than their urban- and suburban-dwelling counterparts, they may be more reliant on smaller corner stores that offer fewer healthful food items. Methods As part of a Communities Putting Prevention to Work (CPPW) healthy corner store initiative, we reviewed audit tools in the fall of 2010 to measure the consumer food environment in eastern North Carolina and chose the NEMS-S-Rev (Nutrition Environment Measures Survey-Stores-Revised) to assess 42 food stores. During the spring and summer of 2011, 2 trained graduate assistants audited stores, achieving interrater reliability of at least 80%. NEMS-S-Rev scores of stores in rural versus urban areas were compared. Results Overall, healthful foods were less available and of lower quality in rural areas than in urban areas. NEMS-S-Rev scores indicated that healthful foods were more likely to be available and had similar pricing and quality in rural corner stores than in urban corner stores. Conclusion Food store audit data provided a baseline to implement and evaluate a CPPW healthy corner store initiative in Pitt County. This work serves as a case study, providing lessons learned for engaging community partners when conducting rural food store audits. PMID:23866165

  14. Combining multiple regression and principal component analysis for accurate predictions for column ozone in Peninsular Malaysia

    NASA Astrophysics Data System (ADS)

    Rajab, Jasim M.; MatJafri, M. Z.; Lim, H. S.

    2013-06-01

    This study encompasses columnar ozone modelling in the peninsular Malaysia. Data of eight atmospheric parameters [air surface temperature (AST), carbon monoxide (CO), methane (CH4), water vapour (H2Ovapour), skin surface temperature (SSKT), atmosphere temperature (AT), relative humidity (RH), and mean surface pressure (MSP)] data set, retrieved from NASA's Atmospheric Infrared Sounder (AIRS), for the entire period (2003-2008) was employed to develop models to predict the value of columnar ozone (O3) in study area. The combined method, which is based on using both multiple regressions combined with principal component analysis (PCA) modelling, was used to predict columnar ozone. This combined approach was utilized to improve the prediction accuracy of columnar ozone. Separate analysis was carried out for north east monsoon (NEM) and south west monsoon (SWM) seasons. The O3 was negatively correlated with CH4, H2Ovapour, RH, and MSP, whereas it was positively correlated with CO, AST, SSKT, and AT during both the NEM and SWM season periods. Multiple regression analysis was used to fit the columnar ozone data using the atmospheric parameter's variables as predictors. A variable selection method based on high loading of varimax rotated principal components was used to acquire subsets of the predictor variables to be comprised in the linear regression model of the atmospheric parameter's variables. It was found that the increase in columnar O3 value is associated with an increase in the values of AST, SSKT, AT, and CO and with a drop in the levels of CH4, H2Ovapour, RH, and MSP. The result of fitting the best models for the columnar O3 value using eight of the independent variables gave about the same values of the R (≈0.93) and R2 (≈0.86) for both the NEM and SWM seasons. The common variables that appeared in both regression equations were SSKT, CH4 and RH, and the principal precursor of the columnar O3 value in both the NEM and SWM seasons was SSKT.

  15. Activation Dependence of Stretch Activation in Mouse Skinned Myocardium: Implications for Ventricular Function

    PubMed Central

    Stelzer, Julian E.; Larsson, Lars; Fitzsimons, Daniel P.; Moss, Richard L.

    2006-01-01

    Recent evidence suggests that ventricular ejection is partly powered by a delayed development of force, i.e., stretch activation, in regions of the ventricular wall due to stretch resulting from torsional twist of the ventricle around the apex-to-base axis. Given the potential importance of stretch activation in cardiac function, we characterized the stretch activation response and its Ca2+ dependence in murine skinned myocardium at 22°C in solutions of varying Ca2+ concentrations. Stretch activation was induced by suddenly imposing a stretch of 0.5–2.5% of initial length to the isometrically contracting muscle and then holding the muscle at the new length. The force response to stretch was multiphasic: force initially increased in proportion to the amount of stretch, reached a peak, and then declined to a minimum before redeveloping to a new steady level. This last phase of the response is the delayed force characteristic of myocardial stretch activation and is presumably due to increased attachment of cross-bridges as a consequence of stretch. The amplitude and rate of stretch activation varied with Ca2+ concentration and more specifically with the level of isometric force prior to the stretch. Since myocardial force is regulated both by Ca2+ binding to troponin-C and cross-bridge binding to thin filaments, we explored the role of cross-bridge binding in the stretch activation response using NEM-S1, a strong-binding, non-force–generating derivative of myosin subfragment 1. NEM-S1 treatment at submaximal Ca2+-activated isometric forces significantly accelerated the rate of the stretch activation response and reduced its amplitude. These data show that the rate and amplitude of myocardial stretch activation vary with the level of activation and that stretch activation involves cooperative binding of cross-bridges to the thin filament. Such a mechanism would contribute to increased systolic ejection in response to increased delivery of activator Ca2+ during

  16. Spatial Interpolation of Historical Seasonal Rainfall Indices over Peninsular Malaysia

    NASA Astrophysics Data System (ADS)

    Hassan, Zulkarnain; Haidir, Ahmad; Saad, Farah Naemah Mohd; Ayob, Afizah; Rahim, Mustaqqim Abdul; Ghazaly, Zuhayr Md.

    2018-03-01

    The inconsistency in inter-seasonal rainfall due to climate change will cause a different pattern in the rainfall characteristics and distribution. Peninsular Malaysia is not an exception for this inconsistency, in which it is resulting extreme events such as flood and water scarcity. This study evaluates the seasonal patterns in rainfall indices such as total amount of rainfall, the frequency of wet days, rainfall intensity, extreme frequency, and extreme intensity in Peninsular Malaysia. 40 years (1975-2015) data records have been interpolated using Inverse Distance Weighted method. The results show that the formation of rainfall characteristics are significance during the Northeast monsoon (NEM), as compared to Southwest monsoon (SWM). Also, there is a high rainfall intensity and frequency related to extreme over eastern coasts of Peninsula during the NEM season.

  17. Development and analysis of a novel cytokine biosensor concept for astronaut immune system monitoring

    NASA Astrophysics Data System (ADS)

    Aponte, Vanessa M.

    The dynamics of how astronauts' immune systems respond to space flight have been studied extensively, but the complex process has not to date been thoroughly characterized, nor have the underlying principles of what causes the immune system to change in microgravity been fully determined. To obtain statistically significant results regarding overall immunological effects in space, collecting in vivo data during flight is desirable, but no sensor is currently capable of performing such function in this environment. The aims of this research were to establish appropriate markers for in-flight monitoring of the immune system and develop a novel approach for a benchtop sensor to measure them. Quartz Crystal Microbalances (QCMs) were used as platforms to study a surface biochemistry process selective towards cytokines, which are used as stress-related immune markers in space and ground medicine. Pilot studies elucidated that a thiolated streptavidin-biotinylated antibody surface assembly did not form the protein monolayer necessary for stable cytokine sensing. Improved experiments incorporated self-assembled monolayers (SAMs) by using di-thiol tethers at the base of a dual antibody sandwich and fluorophore assembly. The goals of the improved experiments were to achieve a stable monolayer of covalently bound tethers, to enhance sensitivity by the addition of a second monoclonal antibody, and to have a fluorescence tether attached to the last antibody layer as a way to corroborate the amount of proteins attached to the surface by using confocal fluorescence microscopy (CFM). Atomic Force Microscopy (AFM) results confirmed the formation of an even protein monolayer at the surface of the QCM, while CFM corroborated that the entire sandwich assembly had been achieved. Frequency changes increased directly proportional to concentration of cytokines, adhering to non-linear behavior explained by viscoelastic fluid models. Results point to the promising use of this surface

  18. Piezoresistive silicon nanowire resonators as embedded building blocks in thick SOI

    NASA Astrophysics Data System (ADS)

    Nasr Esfahani, Mohammad; Kilinc, Yasin; Çagatay Karakan, M.; Orhan, Ezgi; Hanay, M. Selim; Leblebici, Yusuf; Erdem Alaca, B.

    2018-04-01

    The use of silicon nanowire resonators in nanoelectromechanical systems for new-generation sensing and communication devices faces integration challenges with higher-order structures. Monolithic and deterministic integration of such nanowires with the surrounding microscale architecture within the same thick crystal is a critical aspect for the improvement of throughput, reliability and device functionality. A monolithic and IC-compatible technology based on a tuned combination of etching and protection processes was recently introduced yielding silicon nanowires within a 10 μ m-thick device layer. Motivated by its success, the implications of the technology regarding the electromechanical resonance are studied within a particular setting, where the resonator is co-fabricated with all terminals and tuning electrodes. Frequency response is measured via piezoresistive readout with frequency down-mixing. Measurements indicate mechanical resonance with frequencies as high as 100 MHz exhibiting a Lorentzian behavior with proper transition to nonlinearity, while Allan deviation on the order of 3-8 ppm is achieved. Enabling the fabrication of silicon nanowires in thick silicon crystals using conventional semiconductor manufacturing, the present study thus demonstrates an alternative pathway to bottom-up and thin silicon-on-insulator approaches for silicon nanowire resonators.

  19. Ultrahigh Elastic Strain Energy Storage in Metal-Oxide-Infiltrated Patterned Hybrid Polymer Nanocomposites

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dusoe, Keith J.; Ye, Xinyi; Kisslinger, Kim

    Modulus of resilience, the measure of a material’s capacity to store and release elastic strain energy, is critical for realizing advanced mechanical actuation technologies in micro/nanoelectromechanical systems. In general, engineering the modulus of resilience is difficult because it requires asymmetrically increasing yield strength and Young’s modulus against their mutual scaling behavior. This task becomes further challenging if it needs to be carried out at the nanometer scale. Here, we demonstrate organic–inorganic hybrid composite nanopillars with one of the highest modulus of resilience per density by utilizing vapor-phase aluminum oxide infiltration in lithographically patterned negative photoresist SU-8. In situ nanomechanical measurementsmore » reveal a metal-like high yield strength (~500 MPa) with an unusually low, foam-like Young’s modulus (~7 GPa), a unique pairing that yields ultrahigh modulus of resilience, reaching up to ~24 MJ/m 3 as well as exceptional modulus of resilience per density of ~13.4 kJ/kg, surpassing those of most engineering materials. The hybrid polymer nanocomposite features lightweight, ultrahigh tunable modulus of resilience and versatile nanoscale lithographic patternability with potential for application as nanomechanical components which require ultrahigh mechanical resilience and strength.« less

  20. Ultrahigh Elastic Strain Energy Storage in Metal-Oxide-Infiltrated Patterned Hybrid Polymer Nanocomposites

    DOE PAGES

    Dusoe, Keith J.; Ye, Xinyi; Kisslinger, Kim; ...

    2017-10-19

    Modulus of resilience, the measure of a material’s capacity to store and release elastic strain energy, is critical for realizing advanced mechanical actuation technologies in micro/nanoelectromechanical systems. In general, engineering the modulus of resilience is difficult because it requires asymmetrically increasing yield strength and Young’s modulus against their mutual scaling behavior. This task becomes further challenging if it needs to be carried out at the nanometer scale. Here, we demonstrate organic–inorganic hybrid composite nanopillars with one of the highest modulus of resilience per density by utilizing vapor-phase aluminum oxide infiltration in lithographically patterned negative photoresist SU-8. In situ nanomechanical measurementsmore » reveal a metal-like high yield strength (~500 MPa) with an unusually low, foam-like Young’s modulus (~7 GPa), a unique pairing that yields ultrahigh modulus of resilience, reaching up to ~24 MJ/m 3 as well as exceptional modulus of resilience per density of ~13.4 kJ/kg, surpassing those of most engineering materials. The hybrid polymer nanocomposite features lightweight, ultrahigh tunable modulus of resilience and versatile nanoscale lithographic patternability with potential for application as nanomechanical components which require ultrahigh mechanical resilience and strength.« less

  1. Edge Effect of Strained Bilayer Nanofilms for Tunable Multistability and Actuation

    NASA Astrophysics Data System (ADS)

    Chen, Zi; Hu, Nan; Han, Xiaomin; Huang, Shicheng; Grover, Hannah; Yu, Xiaojiao; Zhang, Lina; Trase, Ian; Zhang, John X. J.; Zhang, Li; Dong, Lixin

    Multistability, the capability of a structure to exhibit more than one stable shape, has received increasing attention due to its applications in robotics, and energy harvesters, etc. Programming multistability into nano-electromechanical systems allows for microscale manipulation, energy harvesting and robotic operation for biomedical applications. In a spontaneous scrolled Si/Cr bilayer, two stable shapes were achieved after detaching from the substrate. We employed both theoretical and computational models to study the multistable behavior of a Si/Cr micro-claw and illustrated the mechanical principles involved. Besides the biaxial strain that serves as the primary driving force, we found residual edge stresses to be inducing bistability. In both models, individual Si/Cr micro-claws consistently demonstrate either monostability or bistability as the magnitude of the edge effect is varied. Both macroscopic and microscopic experimental designs were studied, supported by analytical and finite element simulation results. The results from this study provide a means to guide the on-demand design of strained nanobelts and nanosheets with tunable multistability and actuating capability. Z.C. acknowledges the Society in Science-Branco Weiss fellowship. J.X.J.Z. acknowledges the NIH Directors Transformative Award(1R01 OD022910-01).

  2. Strain-engineering of Janus SiC monolayer functionalized with H and F atoms

    NASA Astrophysics Data System (ADS)

    Drissi, L. B.; Sadki, K.; Kourra, M.-H.; Bousmina, M.

    2018-05-01

    Based on ab initio density functional theory calculations, the structural, electronic, mechanical, acoustic, thermodynamic, and piezoelectric properties of (F,H) Janus SiC monolayers are studied. The new set of derivatives shows buckled structures and different band gap values. Under strain, the buckling changes and the structures pass from semiconducting to metallic. The elastic limits and the metastable regions are determined. The Young's modulus and Poisson ratio reveal stronger behavior for the modified conformers with respect to graphene. The values of the Debye temperature make the new materials suitable for thermal application. Moreover, all the conformers show in-plane and out-of-plane piezoelectric responses comparable with known two-dimensional materials. If engineered, such piezoelectric Janus structures may be promising materials for various nanoelectromechanical applications.

  3. Multidirection Piezoelectricity in Mono- and Multilayered Hexagonal α-In2Se3.

    PubMed

    Xue, Fei; Zhang, Junwei; Hu, Weijin; Hsu, Wei-Ting; Han, Ali; Leung, Siu-Fung; Huang, Jing-Kai; Wan, Yi; Liu, Shuhai; Zhang, Junli; He, Jr-Hau; Chang, Wen-Hao; Wang, Zhong Lin; Zhang, Xixiang; Li, Lain-Jong

    2018-05-22

    Piezoelectric materials have been widely used for sensors, actuators, electronics, and energy conversion. Two-dimensional (2D) ultrathin semiconductors, such as monolayer h-BN and MoS 2 with their atom-level geometry, are currently emerging as new and attractive members of the piezoelectric family. However, their piezoelectric polarization is commonly limited to the in-plane direction of odd-number ultrathin layers, largely restricting their application in integrated nanoelectromechanical systems. Recently, theoretical calculations have predicted the existence of out-of-plane and in-plane piezoelectricity in monolayer α-In 2 Se 3 . Here, we experimentally report the coexistence of out-of-plane and in-plane piezoelectricity in monolayer to bulk α-In 2 Se 3 , attributed to their noncentrosymmetry originating from the hexagonal stacking. Specifically, the corresponding d 33 piezoelectric coefficient of α-In 2 Se 3 increases from 0.34 pm/V (monolayer) to 5.6 pm/V (bulk) without any odd-even effect. In addition, we also demonstrate a type of α-In 2 Se 3 -based flexible piezoelectric nanogenerator as an energy-harvesting cell and electronic skin. The out-of-plane and in-plane piezoelectricity in α-In 2 Se 3 flakes offers an opportunity to enable both directional and nondirectional piezoelectric devices to be applicable for self-powered systems and adaptive and strain-tunable electronics/optoelectronics.

  4. The small length scale effect for a non-local cantilever beam: a paradox solved.

    PubMed

    Challamel, N; Wang, C M

    2008-08-27

    Non-local continuum mechanics allows one to account for the small length scale effect that becomes significant when dealing with microstructures or nanostructures. This paper presents some simplified non-local elastic beam models, for the bending analyses of small scale rods. Integral-type or gradient non-local models abandon the classical assumption of locality, and admit that stress depends not only on the strain value at that point but also on the strain values of all points on the body. There is a paradox still unresolved at this stage: some bending solutions of integral-based non-local elastic beams have been found to be identical to the classical (local) solution, i.e. the small scale effect is not present at all. One example is the Euler-Bernoulli cantilever nanobeam model with a point load which has application in microelectromechanical systems and nanoelectromechanical systems as an actuator. In this paper, it will be shown that this paradox may be overcome with a gradient elastic model as well as an integral non-local elastic model that is based on combining the local and the non-local curvatures in the constitutive elastic relation. The latter model comprises the classical gradient model and Eringen's integral model, and its application produces small length scale terms in the non-local elastic cantilever beam solution.

  5. Neighbourhood and consumer food environment is associated with dietary intake among Supplemental Nutrition Assistance Program (SNAP) participants in Fayette County, Kentucky.

    PubMed

    Gustafson, Alison; Lewis, Sarah; Perkins, Sarah; Wilson, Corey; Buckner, Elizabeth; Vail, Ann

    2013-07-01

    The aim of the study was to determine the association between dietary outcomes and the neighbourhood food environment (street network distance from home to stores) and consumer food environment (Nutrition Environment Measurement Survey-Stores (NEMS-S) audit). The neighbourhood food environment was captured by creating 0?5-mile and 1-mile network distance (street distance) around each participant’s home and the nearest food venue (convenience store, grocery store, supermarket, farmers’ market and produce stand). The consumer food environment was captured by conducting NEMS-S in all grocery stores/supermarkets within 0?5 and 1 mile of participants’ homes. Fayette County, KY, USA. Supplemental Nutrition Assessment Program (SNAP) participants, n 147. SNAP participants who lived within 0?5 mile of at least one farmers’ market/produce stand had higher odds of consuming one serving or more of vegetables (OR56?92; 95% CI 4?09, 11?69), five servings or more of grains (OR51?76; 95% CI 1?01, 3?05) and one serving or more of milk (OR53?79; 95% CI 2?14, 6?71) on a daily basis. SNAP participants who lived within 0?5 mile of stores receiving a high score on the NEMS-S audit reported higher odds of consuming at least one serving of vegetables daily (OR53?07; 95% CI 1?78, 5?31). Taken together, both the neighbourhood food environment and the consumer food environment are associated with a healthy dietary intake among SNAP participants.

  6. [The measurement of nursing workload in a sub-intensive unit with the Nine Equivalents of Nursing Manpower Scale].

    PubMed

    D'Orazio, Alessia; Dragonetti, Antonella; Finiguerra, Ivana; Simone, Paola

    2015-01-01

    The measurement of nursing workload in a sub-intensive unit with the Nine Equivalents of Nursing Manpower Scale. The need to maximize the nursing manpower to patients complexity requires a careful assessment of the nursing workload. To measure the nursing workload in a sub-intensive care unit and to assess the impact of patients isolated for multidrug resistant microorganisms (MDR) and with delirium, on the nursing workload. From december 1 2014 to march 31 2015 the nursing workload of patients admitted to a semi intensive untit of a Turin Hospital was measured with Nine Equivalents of Nursing Manpower (NEMS) original and modified, adding 1 point score for patients isolated and with delirium (Richmond Agitation Sedation Scale). Admission and discharge times, and the activities performed in and out of the unit were registered. Two-hundred-thirty patients were daily assessed and no differences were observed in mean NEMS scores with the original and modified scale: december 17.3 vs 18.5; January 19.4 vs 20.2; February 19.9 vs 20.6; March 19.5 vs 20.1). mean scores did not change across shifts although on average 8 days a month the scores exceeded 21, identifiyng an excess workload and a need of a 2:1 patient/nurse ratio. The maximum workload was concentrated between 12.00 and 18.00 pm. The NEMS scale allows to measure the nursing workload. Apparently patients isolated and with delirium did not significantly impact on the nursing workload.

  7. Role of the His-Cys finger of Moloney murine leukemia virus integrase protein in integration and disintegration.

    PubMed Central

    Jonsson, C B; Roth, M J

    1993-01-01

    Retroviral integrases mediate site-specific endonuclease and transesterification reactions in the absence of exogenous energy. The basis for the sequence specificity in these integrase-viral DNA recognition processes is unknown. Structural analogs of the disintegration substrate were made to analyze the disintegration reaction mechanism for the Moloney murine leukemia virus (M-MuLV) integrase (IN). Modifications in the target DNA portion of the disintegration substrate decreased enzymatic activity, while substitution of the highly conserved CA in the viral long terminal repeat portion had no effect on activity. The role of the His-Cys finger region in catalysis was addressed by N-ethylmaleimide (NEM) modification of the cysteine residues of M-MuLV IN as well as by mutations. Both integration activities, 3' processing, and strand transfer, were completely inhibited by NEM modification of M-MuLV IN, while disintegration activity was only partially sensitive. However, structural analogs of the disintegration substrates that were modified in the target DNA and had the conserved CA removed were not active with NEM-treated M-MuLV IN. In addition, mutants made in the His-Cys region of M-MuLV IN were examined and found to also be completely blocked in integration but not disintegration activity. These data suggest that the domains of M-MuLV IN that are required for the forward integration reaction substrate differ from those required for the reverse disintegration reaction substrate. Images PMID:8350412

  8. Development of JPSS VIIRS Global Gridded Vegetation Index products for NOAA NCEP Environmental Modeling Systems

    NASA Astrophysics Data System (ADS)

    Vargas, Marco; Miura, Tomoaki; Csiszar, Ivan; Zheng, Weizhong; Wu, Yihua; Ek, Michael

    2017-04-01

    The first Joint Polar Satellite System (JPSS) mission, the Suomi National Polar-orbiting Partnership (S-NPP) satellite, was successfully launched in October, 2011, and it will be followed by JPSS-1, slated for launch in 2017. JPSS provides operational continuity of satellite-based observations and products for NOAA's Polar Operational Environmental Satellites (POES). Vegetation products derived from satellite measurements are used for weather forecasting, land modeling, climate research, and monitoring the environment including drought, the health of ecosystems, crop monitoring and forest fires. The operationally produced S-NPP VIIRS Vegetation Index (VI) Environmental Data Record (EDR) includes two vegetation indices: the Top of the Atmosphere (TOA) Normalized Difference Vegetation Index (NDVI), and the Top of the Canopy (TOC) Enhanced Vegetation Index (EVI). For JPSS-1, the S-NPP Vegetation Index EDR algorithm has been updated to include the TOC NDV. The current JPSS operational VI products are generated in granule style at 375 meter resolution at nadir, but these products in granule format cannot be ingested into NOAA operational monitoring and decision making systems. For that reason, the NOAA JPSS Land Team is developing a new global gridded Vegetation Index (VI) product suite for operational use by the NOAA National Centers for Environmental Prediction (NCEP). The new global gridded VIs will be used in the Multi-Physics (MP) version of the Noah land surface model (Noah-MP) in NCEP NOAA Environmental Modeling System (NEMS) for plant growth and data assimilation and to describe vegetation coverage and density in order to model the correct surface energy partition. The new VI 4km resolution global gridded products (TOA NDVI, TOC NDVI and TOC EVI) are being designed to meet the needs of directly ingesting vegetation index variables without the need to develop local gridding and compositing procedures. These VI products will be consistent with the already

  9. Applications and Methods of Operating a Three-dimensional Nano-electro-mechanical Resonator and Related Devices

    NASA Technical Reports Server (NTRS)

    Kaul, Anupama B. (Inventor); Epp, Larry W. (Inventor); Bagge, Leif (Inventor)

    2013-01-01

    Carbon nanofiber resonator devices, methods for use, and applications of said devices are disclosed. Carbon nanofiber resonator devices can be utilized in or as high Q resonators. Resonant frequency of these devices is a function of configuration of various conducting components within these devices. Such devices can find use, for example, in filtering and chemical detection.

  10. EDITORIAL: CAMOP: Quantum Non-Stationary Systems CAMOP: Quantum Non-Stationary Systems

    NASA Astrophysics Data System (ADS)

    Dodonov, Victor V.; Man'ko, Margarita A.

    2010-09-01

    Although time-dependent quantum systems have been studied since the very beginning of quantum mechanics, they continue to attract the attention of many researchers, and almost every decade new important discoveries or new fields of application are made. Among the impressive results or by-products of these studies, one should note the discovery of the path integral method in the 1940s, coherent and squeezed states in the 1960-70s, quantum tunneling in Josephson contacts and SQUIDs in the 1960s, the theory of time-dependent quantum invariants in the 1960-70s, different forms of quantum master equations in the 1960-70s, the Zeno effect in the 1970s, the concept of geometric phase in the 1980s, decoherence of macroscopic superpositions in the 1980s, quantum non-demolition measurements in the 1980s, dynamics of particles in quantum traps and cavity QED in the 1980-90s, and time-dependent processes in mesoscopic quantum devices in the 1990s. All these topics continue to be the subject of many publications. Now we are witnessing a new wave of interest in quantum non-stationary systems in different areas, from cosmology (the very first moments of the Universe) and quantum field theory (particle pair creation in ultra-strong fields) to elementary particle physics (neutrino oscillations). A rapid increase in the number of theoretical and experimental works on time-dependent phenomena is also observed in quantum optics, quantum information theory and condensed matter physics. Time-dependent tunneling and time-dependent transport in nano-structures are examples of such phenomena. Another emerging direction of study, stimulated by impressive progress in experimental techniques, is related to attempts to observe the quantum behavior of macroscopic objects, such as mirrors interacting with quantum fields in nano-resonators. Quantum effects manifest themselves in the dynamics of nano-electromechanical systems; they are dominant in the quite new and very promising field of circuit

  11. Resonance energy transfer between sites in rat liver glutathione S-transferase, 1-1, selectively modified at cysteine-17 and cysteine-111.

    PubMed

    Hu, L; Colman, R F

    1997-02-18

    Monobromobimane (mBBr) can label both Cys111 and Cys17 of rat liver glutathione S-transferase, 1-1 (GST 1-1). However, selective modification of Cys111 was achieved by the maleimide-based sulfhydryl reagents N-ethylmaleimide (NEM) and fluorescein 5-maleimide (NFM). Incubation of GST 1-1 with 5 mM NEM for 30 min at pH 7.5 and 25 degrees C leads to the formation of modified enzyme with 92% residual activity toward 1-chloro-2,4-dinitrobenzene and completely blocks Cys111 from subsequent reaction with either NFM or mBBr. Reaction of GST 1-1 with 0.2 mM NFM under the same conditions affords a modified enzyme with only 14% residual activity even though NFM and NEM target the same Cys111. The results indicate that when the bulky fluorescein is covalently bound to Cys111, the ligand projects into both the xenobiotic binding site and the glutathione site. After NEM or NFM modification of GST 1-1, the enzyme was further modified by monobromobimane at Cys17 with loss of activity. Together with the only tryptophan (Trp20), fluorescein linked to Cys111 and bimane to Cys17 provide three fluorescent probes to study the solution structure of GST 1-1. Fluorescence spectral analysis suggests that Trp20 and bimane linked to Cys17 are located in a relatively hydrophobic environment, while fluorescein linked to Cys111 is located in a charged environment. These fluorescent probes constitute three sets of donor-acceptor pairs for the measurement of fluorescence energy transfer, and distances calculated from such measurements are 20 A between Trp20 and bimane at Cys17, 19 A between Trp20 and fluorescein at Cys111, and < 22 A between bimane at Cys17 and fluorescein at Cys111. Molecular modeling studies indicate that fluorescein lies between the two subunits, is surrounded by charged residues, and is extended into the xenobiotic binding site. They also suggest that mBBr must approach from the dimer interface in order to reach the reaction site at Cys17.

  12. Effects of Gold Salt Speciation and Structure of Human and Bovine Serum Albumin on the Synthesis and Stability of Gold Nanostructures

    NASA Astrophysics Data System (ADS)

    Miranda, Érica; Tofanello, Aryane; Brito, Adrianne; Lopes, David; Giacomelli, Fernando; Albuquerque, Lindomar; Costa, Fanny; Ferreira, Fabio; Araujo-Chaves, Juliana; de Castro, Carlos; Nantes, Iseli

    2016-03-01

    The present study aimed to investigate the influence of albumin structure and gold speciation on the synthesis of gold nanoparticles (GNPs). The strategy of synthesis was the addition of HAuCl4 solutions at different pH values (3-12) to solutions of human and bovine serum albumins (HSA and BSA) at the same corresponding pH values. Different pH values influence the GNP synthesis due to gold speciation. Besides the inherent effect of pH on the native structure of albumins, the use N-ethylmaleimide (NEM)-treated and heat-denaturated forms of HSA and BSA provided additional insights about the influence of protein structure, net charge, and thiol group approachability on the GNP synthesis. NEM treatment, heating, and the extreme values of pH promoted loss of the native albumin structure. The formation of GNPs indicated by the appearance of surface plasmon resonance (SPR) bands became detectable from fifteen days of the synthesis processes that were carried out with native, NEM-treated and heat-denaturated forms of HSA and BSA, exclusively at pH 6 and 7. After two months of incubation, SPR band was also detected for all synthesis carried out at pH 8.0. The mean values of the hydrodynamic radius (RH) were 24 and 34 nm for GNPs synthesized with native HSA and BSA, respectively. X-ray diffraction (XRD) revealed crystallites of 13 nm. RH, XRD, and zeta potential values were consistent with GNP capping by the albumins. However, the GNPs produced with NEM-treated and heat-denaturated albumins exhibited loss of protein capping by lowering the ionic strength. This result suggests a significant contribution of non-electrostatic interactions of albumins with the GNP surface, in these conditions. The denaturation of proteins exposes hydrophobic groups to the solvent, and these groups could interact with the gold surface. In these conditions, the thiol blockage or oxidation, the latter probably favored upon heating, impaired the formation of a stable capping by thiol coordination

  13. Remotely Searching for Noctiluca Miliaris in the Arabian Sea

    NASA Technical Reports Server (NTRS)

    Werdell, P. Jeremy; Roesler, Collin S.; Goes, Joaquim I.

    2014-01-01

    Reversing monsoonal winds in the Arabian Sea result in two seasons with elevated biological activity, namely the annual summer Southwest Monsoon (SWM; June to September) and winter Northeast Monsoon (NEM; November to March) [Wiggert et al., 2005]. Generally speaking, the SWM and NEM create two geographically distinct blooms [Banse and English, 2000; Levy et al., 2007]. In the summer, winds from the southwest drive offshore Ekman transport and coastal upwelling along the northwestern coast of Africa, which brings nutrient-rich water to the surface from below the permanent thermocline [Bauer et al., 1991]. In the winter, cooling of the northern Arabian Sea causes surface waters to sink, which generates convective mixing that injects nutrients throughout the upper mixed layer [Madhupratap et al., 1996]. This fertilization of otherwise nutrient-deplete surface waters produces one of the most substantial seasonal extremes of phytoplankton biomass and carbon flux anywhere in the world [Smith, 2005].

  14. Influence of some DNA-alkylating drugs on thermal stability, acid and osmotic resistance of the membrane of whole human erythrocytes and their ghosts.

    PubMed

    Ivanov, I T; Gadjeva, V

    2000-09-01

    Human erythrocytes and their resealed ghosts were alkylated under identical conditions using three groups of alkylating antitumor agents: mustards, triazenes and chloroethyl nitrosoureas. Osmotic fragility, acid resistance and thermal stability of membranes were changed only in alkylated ghosts in proportion to the concentration of the alkylating agent. All the alkylating agents decreased acid resistance in ghosts. The clinically used drugs sarcolysine, dacarbazine and lomustine all decreased osmotic fragility and thermal stability of ghost membranes depending on their lipophilicity. DM-COOH did not decrease osmotic fragility and thermal stability of ghost membranes, while NEM increased thermal stability of membranes. The preliminary but not subsequent treatment of ghosts with DM-COOH fully abolished the alkylation-induced thermal labilization of ghost membrane proteins while NEM had a partial effect only. The present study gives direct evidence that alkylating agents, having a high therapeutic activity against malignant growth, bind covalently to proteins of cellular membranes.

  15. Kinetic and stoichiometric constraints determine the pathway of H2O2 consumption by red blood cells.

    PubMed

    Orrico, Florencia; Möller, Matías N; Cassina, Adriana; Denicola, Ana; Thomson, Leonor

    2018-05-09

    Red blood cells (RBC) are considered as a circulating sink of H 2 O 2 , but a significant debate remains over the role of the different intraerythocyte peroxidases. Herein we examined the kinetic of decomposition of exogenous H 2 O 2 by human RBC at different cell densities, using fluorescent and oxymetric methods, contrasting the results against a mathematical model. Fluorescent measurements as well as oxygen production experiments showed that catalase was responsible for most of the decomposition of H 2 O 2 at cell densities suitable for both experimental settings (0.1-10 × 10 10 cell L -1 ), since sodium azide but not N-ethylmaleimide (NEM) inhibited H 2 O 2 consumption. Oxygen production decreased at high cell densities until none was detected above 1.1 × 10 12 cell L- 1 , being recovered after inhibition of the thiol dependent systems by NEM. This result underlined that the consumption of H 2 O 2 by catalase prevail at RBC densities regularly used for research, while the thiol dependent systems predominate when the cell density increases, approaching the normal number in blood (5 × 10 12 cell L- 1 ). The mathematical model successfully reproduced experimental results and at low cell number it showed a time sequence involving Prx as the first line of defense, followed by catalase, with a minor role by Gpx. The turning points were given by the total consumption of reduced Prx in first place and reduced GSH after that. However, Prx alone was able to account for the added H 2 O 2 (50µM) at physiological RBC density, calling attention to the importance of cell density in defining the pathway of H 2 O 2 consumption and offering an explanation to current apparently conflicting results in the literature. Copyright © 2018. Published by Elsevier Inc.

  16. Single-crystalline graphene radio-frequency nanoswitches

    NASA Astrophysics Data System (ADS)

    Li, Peng; Cui, Tianhong

    2015-07-01

    Growth of monolayer single-crystalline graphene (SCG) using the low-pressure chemical vapor deposition method is reported. Graphene’s superb quality and single-crystalline nature were characterized and verified by Raman microscopy, atomic force microscopy, and carrier mobility measurement. Radio-frequency (RF) nanoelectromechanical switches based on coplanar waveguide double-clamped SCG membrane were achieved, and the superb properties of SCG enable the switches to operate at a pull-in voltage as low as 1 V, with switch time in the nanosecond regime. Owing to their single-crystalline nature, the switches’ lifetime (>5000 times) is much longer than that of polycrystalline graphene ones reported. The RF devices exhibit good isolation (-30 dB at 40 GHz (Ka band)), which can be further improved by SCG’s conductivity variation due to actuation voltage.

  17. Electronic zero-point fluctuation forces inside circuit components

    PubMed Central

    Leonhardt, Ulf

    2018-01-01

    One of the most intriguing manifestations of quantum zero-point fluctuations are the van der Waals and Casimir forces, often associated with vacuum fluctuations of the electromagnetic field. We study generalized fluctuation potentials acting on internal degrees of freedom of components in electrical circuits. These electronic Casimir-like potentials are induced by the zero-point current fluctuations of any general conductive circuit. For realistic examples of an electromechanical capacitor and a superconducting qubit, our results reveal the possibility of tunable forces between the capacitor plates, or the level shifts of the qubit, respectively. Our analysis suggests an alternative route toward the exploration of Casimir-like fluctuation potentials, namely, by characterizing and measuring them as a function of parameters of the environment. These tunable potentials may be useful for future nanoelectromechanical and quantum technologies. PMID:29719863

  18. Shuttle-promoted nano-mechanical current switch

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Song, Taegeun, E-mail: tsong@ictp.it; Kiselev, Mikhail N.; Gorelik, Leonid Y.

    2015-09-21

    We investigate electron shuttling in three-terminal nanoelectromechanical device built on a movable metallic rod oscillating between two drains. The device shows a double-well shaped electromechanical potential tunable by a source-drain bias voltage. Four stationary regimes controllable by the bias are found for this device: (i) single stable fixed point, (ii) two stable fixed points, (iii) two limit cycles, and (iv) single limit cycle. In the presence of perpendicular magnetic field, the Lorentz force makes possible switching from one electromechanical state to another. The mechanism of tunable transitions between various stable regimes based on the interplay between voltage controlled electromechanical instabilitymore » and magnetically controlled switching is suggested. The switching phenomenon is implemented for achieving both a reliable active current switch and sensoring of small variations of magnetic field.« less

  19. A role for cysteine 3635 of RYR1 in redox modulation and calmodulin binding

    NASA Technical Reports Server (NTRS)

    Porter Moore, C.; Zhang, J. Z.; Hamilton, S. L.

    1999-01-01

    Oxidation of the skeletal muscle Ca(2+) release channel (RYR1) increases its activity, produces intersubunit disulfide bonds, and blocks its interaction with calmodulin. Conversely, bound calmodulin protects RYR1 from the effects of oxidants (Zhang, J.-Z., Wu, Y., Williams, B. Y., Rodney, G., Mandel, F., Strasburg, G. M., and Hamilton, S. L. (1999) Am. J. Physiol. 276, Cell Physiol. C46-C53). In addition, calmodulin protects RYR1 from trypsin cleavage at amino acids 3630 and 3637 (Moore, C. P., Rodney, G., Zhang, J.-Z., Santacruz-Toloza, L., Strasburg, G. M., and Hamilton, S. L. (1999) Biochemistry 38, 8532-8537). The sequence between these two tryptic sites is AVVACFR. Alkylation of RYR1 with N-ethylmaleimide (NEM) blocks both (35)S-apocalmodulin binding and oxidation-induced intersubunit cross-linking. In the current work, we demonstrate that both cysteines needed for the oxidation-induced intersubunit cross-link are protected from alkylation with N-ethylmaleimide by bound calmodulin. We also show, using N-terminal amino acid sequencing together with analysis of the distribution of [(3)H]NEM labeling with each sequencing cycle, that cysteine 3635 of RYR1 is rapidly labeled by NEM and that this labeling is blocked by bound calmodulin. We propose that cysteine 3635 is located at an intersubunit contact site that is close to or within a calmodulin binding site. These findings suggest that calmodulin and oxidation modulate RYR1 activity by regulating intersubunit interactions in a mutually exclusive manner and that these interactions involve cysteine 3635.

  20. Urban-rural inequality regarding drug prescriptions in primary care facilities - a pre-post comparison of the National Essential Medicines Scheme of China.

    PubMed

    Yao, Qiang; Liu, Chaojie; Ferrier, J Adamm; Liu, Zhiyong; Sun, Ju

    2015-07-30

    To assess the impact of the National Essential Medicines Scheme (NEMS) with respect to urban-rural inequalities regarding drug prescriptions in primary care facilities. A stratified two-stage random sampling strategy was used to sample 23,040 prescriptions from 192 primary care facilities from 2009 to 2010. Difference-in-Difference (DID) analyses were performed to test the association between NEMS and urban-rural gaps in prescription patterns. Between-Group Variance and Theil Index were calculated to measure urban-rural absolute and relative disparities in drug prescriptions. The use of the Essential Medicines List (EML) achieved a compliance rate of up to 90% in both urban and rural facilities. An overall reduction of average prescription cost improved economic access to drugs for patients in both areas. However, we observed an increased urban-rural disparity in average expenditure per prescription. The rate of antibiotics and glucocorticoids prescription remained high, despite a reduced disparity between urban and rural facilities. The average incidence of antibiotic prescription increased slightly in urban facilities (62 to 63%) and reduced in rural facilities (67% to 66%). The urban-rural disparity in the use of parenteral administration (injections and infusions) increased, albeit at a high level in both areas (44%-52%). NEMS interventions are effective in reducing the overall average prescription costs. Despite the increased use of the EML, indicator performances with respect to rational drug prescribing and use remain poor and exceed the WHO/INRUD recommended cutoff values and worldwide benchmarks. There is an increased gap between urban and rural areas in the use of parenteral administration and expenditure per prescription.

  1. Neighborhood impact on healthy food availability and pricing in food stores.

    PubMed

    Krukowski, Rebecca A; West, Delia Smith; Harvey-Berino, Jean; Elaine Prewitt, T

    2010-06-01

    Availability and price of healthy foods in food stores has the potential to influence purchasing patterns, dietary intake, and weight status of individuals. This study examined whether demographic factors of the store neighborhood or store size have an impact on the availability and price of healthy foods in sample of grocery stores and supermarkets. The Nutrition Environment Measures Study-Store (NEMS-S) instrument, a standardized observational survey, was utilized to evaluate food stores (N = 42) in a multi-site (Vermont and Arkansas) study in 2008. Census data associated with store census tract (median household income and proportion African-American) were used to characterize store neighborhood and number of cash registers was used to quantify store size. Median household income was significantly associated with the NEMS healthy food availability score (r = 0.36, P < 0.05); neither racial composition (r = -0.23, P = 0.14) nor store size (r = 0.27, P = 0.09) were significantly related to the Availability score. Larger store size (r = 0.40, P < 0.01) was significantly associated with the NEMS-S Price scores, indicating more favorable prices for healthier items; neither racial composition nor median household income were significantly related to the Price score (P's > 0.05). Even among supermarkets, healthier foods are less available in certain neighborhoods, although, when available, the quality of healthier options did not differ, suggesting that targeting availability may offer promise for policy initiatives. Furthermore, increasing access to larger stores that can offer lower prices for healthier foods may provide another avenue for enhancing food environments to lower disease risk.

  2. The value of electricity storage in energy-only electricity markets

    NASA Astrophysics Data System (ADS)

    McConnell, D.; Forcey, T.; Sandiford, M.

    2015-12-01

    Price volatility and the prospect of increasing renewable energy generation have raised interest in the potential opportunities for storage technologies in energy-only electricity markets. In this paper we explore the value of a price-taking storage device in such a market, the National Electricity Market (NEM) in Australia. Our analysis suggests that under optimal operation, there is little value in having more than six hours of storage in this market. However, the inability to perfectly forecast wholesale prices, particularly extreme price spikes, may warrant some additional storage. We found that storage devices effectively provide a similar service as peak generators (such as Open Cycle Gas Turbines) and are similarly dependent on and exposed to extreme price events, with revenue for a merchant generator highly skewed to a few days of the year. In contrast to previous studies, this results in the round trip efficiency of the storage being relatively insignificant. Financing using hedging strategies similar to a peak generator effectively reduces the variability of revenue and exposure of storage to extreme prices. Our case study demonstrates that storage may have a competitive advantage over other peaking generators on the NEM, due to its ability to earn revenue outside of extreme peak events. As a consequence the outlook for storage options on the NEM is dependent on volatility, in turn dependent on capacity requirements. Further to this, increased integration of renewable energy may both depend on storage and improve the outlook for storage in technologies in electricity markets.

  3. Nanofriction: Skating on hot surfaces

    NASA Astrophysics Data System (ADS)

    Meyer, Ernst; Gnecco, Enrico

    2007-03-01

    Simulations of nanoscale sharp tips sliding on a salt surface predict vanishing friction at temperatures close to the melting temperature, as the tip skates on a layer of liquefied salt. This insight opens the way to applications in MEMS, NEMS and auto/aerospace engines.

  4. 75 FR 17803 - Self-Regulatory Organizations; NASDAQ OMX PHLX, Inc.; Notice of Filing and Immediate...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-07

    .... The text of the proposed rule change is available on the Exchange's Web site at http://nasdaqtrader... and discussed any comments it received on the proposed rule change. The text of these statements may... Mining Corporation (``NEM''); Palm, Inc. (``PALM''); Pfizer, Inc. (``PFE''); ''); Potash Corp...

  5. Signaling molecule methylglyoxal ameliorates cadmium injury in wheat (Triticum aestivum L) by a coordinated induction of glutathione pool and glyoxalase system.

    PubMed

    Li, Zhong-Guang; Nie, Qian; Yang, Cong-Li; Wang, Yue; Zhou, Zhi-Hao

    2018-03-01

    Methylglyoxal (MG) now is found to be an emerging signaling molecule. It can relieve the toxicity of cadmium (Cd), however its alleviating mechanism still remains unknown. In this study, compared with the Cd-stressed seedlings without MG treatment, MG treatment could stimulate the activities of glutathione reductase (GR) and gamma-glutamylcysteine synthetase (γ-ECS) in Cd-stressed wheat seedlings, which in turn induced an increase of reduced glutathione (GSH). Adversely, the activated enzymes related to GSH biosynthesis and increased GSH were weakened by N-acetyl-L-cysteine (NAC, MG scavenger), 2,4-dihydroxy-benzylamine (DHBA) and 1,3-bischloroethyl-nitrosourea (BCNU, both are specific inhibitors of GR), buthionine sulfoximine (BSO, a specific inhibitors of GSH biosynthesis), and N-ethylmaleimide (NEM, GSH scavenger), respectively. In addition, MG increased the activities of glyoxalase I (Gly I) and glyoxalase II (Gly II) in Cd-treated seedlings, followed by declining an increase in endogenous MG as comparision to Cd-stressed seedlings alone. On the contrary, the increased glyoxalase activity and decreased endogenous MG level were reversed by NAC and specific inhibitors of Gly I (isoascorbate, IAS; squaric acid, SA). Furthermore, MG alleviated an increase in hydrogen peroxide (H 2 O 2 ) and malondialdehyde (MDA) in Cd-treated wheat seedlings. These results indicated that MG could alleviate Cd toxicity and improve the growth of Cd-stressed wheat seedlings by a coordinated induction of glutathione pool and glyoxalase system. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Single walled boron nitride nanotube-based biosensor: an atomistic finite element modelling approach.

    PubMed

    Panchal, Mitesh B; Upadhyay, Sanjay H

    2014-09-01

    The unprecedented dynamic characteristics of nanoelectromechanical systems make them suitable for nanoscale mass sensing applications. Owing to superior biocompatibility, boron nitride nanotubes (BNNTs) are being increasingly used for such applications. In this study, the feasibility of single walled BNNT (SWBNNT)-based bio-sensor has been explored. Molecular structural mechanics-based finite element (FE) modelling approach has been used to analyse the dynamic behaviour of SWBNNT-based biosensors. The application of an SWBNNT-based mass sensing for zeptogram level of mass has been reported. Also, the effect of size of the nanotube in terms of length as well as different chiral atomic structures of SWBNNT has been analysed for their sensitivity analysis. The vibrational behaviour of SWBNNT has been analysed for higher-order modes of vibrations to identify the intermediate landing position of biological object of zeptogram scale. The present molecular structural mechanics-based FE modelling approach is found to be very effectual to incorporate different chiralities of the atomic structures. Also, different boundary conditions can be effectively simulated using the present approach to analyse the dynamic behaviour of the SWBNNT-based mass sensor. The presented study has explored the potential of SWBNNT, as a nanobiosensor having the capability of zeptogram level mass sensing.

  7. Giant slip lengths of a simple fluid at vibrating solid interfaces

    NASA Astrophysics Data System (ADS)

    Drezet, Aurélien; Siria, Alessandro; Huant, Serge; Chevrier, Joël

    2010-04-01

    It has been shown recently [A. Siria, A. Drezet, F. Marchi, F. Comin, S. Huant, and J. Chevrier, Phys. Rev. Lett. 102, 254503 (2009)] that in the plane-plane configuration, a mechanical resonator vibrating close to a rigid wall in a simple fluid can be overdamped to a frozen regime. Here, by solving analytically the Navier-Stokes equations with partial slip boundary conditions at the solid-fluid interface, we develop a theoretical approach justifying and extending these earlier findings. We show in particular that in the perfect-slip regime, the abovementioned results are, in the plane-plane configuration, very general and robust with respect to lever geometry considerations. We compare the results to those obtained previously for the sphere moving perpendicularly and close to a plane in a simple fluid and discuss in more details the differences concerning the dependence of the friction forces with the gap distance separating the moving object (i.e., plane or sphere) from the fixed plane. We show that the plane-plane geometry is more sensitive than the sphere-plane geometry for the measurement of slippage coefficients. Finally, we show that the submicron fluidic effect reported in the reference above, and discussed further in the present work, can have dramatic implications in the design of nanoelectromechanical systems.

  8. Giant slip lengths of a simple fluid at vibrating solid interfaces.

    PubMed

    Drezet, Aurélien; Siria, Alessandro; Huant, Serge; Chevrier, Joël

    2010-04-01

    It has been shown recently [A. Siria, A. Drezet, F. Marchi, F. Comin, S. Huant, and J. Chevrier, Phys. Rev. Lett. 102, 254503 (2009)] that in the plane-plane configuration, a mechanical resonator vibrating close to a rigid wall in a simple fluid can be overdamped to a frozen regime. Here, by solving analytically the Navier-Stokes equations with partial slip boundary conditions at the solid-fluid interface, we develop a theoretical approach justifying and extending these earlier findings. We show in particular that in the perfect-slip regime, the abovementioned results are, in the plane-plane configuration, very general and robust with respect to lever geometry considerations. We compare the results to those obtained previously for the sphere moving perpendicularly and close to a plane in a simple fluid and discuss in more details the differences concerning the dependence of the friction forces with the gap distance separating the moving object (i.e., plane or sphere) from the fixed plane. We show that the plane-plane geometry is more sensitive than the sphere-plane geometry for the measurement of slippage coefficients. Finally, we show that the submicron fluidic effect reported in the reference above, and discussed further in the present work, can have dramatic implications in the design of nanoelectromechanical systems.

  9. Piezoelectric actuated micro-resonators based on the growth of diamond on aluminum nitride thin films.

    PubMed

    Hees, J; Heidrich, N; Pletschen, W; Sah, R E; Wolfer, M; Williams, O A; Lebedev, V; Nebel, C E; Ambacher, O

    2013-01-18

    Unimorph heterostructures based on piezoelectric aluminum nitride (AlN) and diamond thin films are highly desirable for applications in micro- and nanoelectromechanical systems. In this paper, we present a new approach to combine thin conductive boron-doped as well as insulating nanocrystalline diamond (NCD) with sputtered AlN films without the need for any buffer layers between AlN and NCD or polishing steps. The zeta potentials of differently treated nanodiamond (ND) particles in aqueous colloids are adjusted to the zeta potential of AlN in water. Thereby, the nucleation density for the initial growth of diamond on AlN can be varied from very low (10(8) cm(-2)), in the case of hydrogen-treated ND seeding particles, to very high values of 10(11) cm(-2) for oxidized ND particles. Our approach yielding high nucleation densities allows the growth of very thin NCD films on AlN with thicknesses as low as 40 nm for applications such as microelectromechanical beam resonators. Fabricated piezo-actuated micro-resonators exhibit enhanced mechanical properties due to the incorporation of boron-doped NCD films. Highly boron-doped NCD thin films which replace the metal top electrode offer Young's moduli of more than 1000 GPa.

  10. Design, implementation, and application of a microresonator platform for measuring energy dissipation by internal friction in nanowires.

    PubMed

    Das, Kaushik; Sosale, Guruprasad; Vengallatore, Srikar

    2012-12-21

    Accurate measurements of internal friction in nanowires are required for the rational design of high-Q resonators used in nanoelectromechanical systems and for fundamental studies of nanomechanical behavior. However, measuring internal friction is challenging because of the difficulties associated with identifying the contributions of material dissipation to structural damping. Here, we present an approach for overcoming these difficulties by using a composite microresonator platform that is calibrated against the ultimate limits of thermoelastic damping. The platform consists of an array of nanowires patterned at the root of a low-loss single-crystal silicon microcantilever. The structure is processed using a lift-off technique, implemented using electron-beam lithography, to achieve excellent control over the size, alignment, dispersion and location of the nanowire array. As the first application of this platform, we measured internal friction at room temperature in aluminum nanowires that ranged from 50 to 100 nm in thickness and 100 to 400 nm in width. Internal friction is ~0.03 at frequencies of 6.5-21 kHz. Transmission electron microscopy of the nanocrystalline grain structure, and comparison with previously measured values of internal friction in continuous thin films of aluminum, suggest that grain-boundary sliding is a major source of internal friction in these nanowires.

  11. Gold Nanorod Rotary Motors Driven by Resonant Light Scattering.

    PubMed

    Shao, Lei; Yang, Zhong-Jian; Andrén, Daniel; Johansson, Peter; Käll, Mikael

    2015-12-22

    Efficient and robust artificial nanomotors could provide a variety of exciting possibilities for applications in physics, biology and chemistry, including nanoelectromechanical systems, biochemical sensing, and drug delivery. However, the application of current man-made nanomotors is limited by their sophisticated fabrication techniques, low mechanical output power and severe environmental requirements, making their performance far below that of natural biomotors. Here we show that single-crystal gold nanorods can be rotated extremely fast in aqueous solutions through optical torques dominated by plasmonic resonant scattering of circularly polarized laser light with power as low as a few mW. The nanorods are trapped in 2D against a glass surface, and their rotational dynamics is highly dependent on their surface plasmon resonance properties. They can be kept continuously rotating for hours with limited photothermal side effects and they can be applied for detection of molecular binding with high sensitivity. Because of their biocompatibility, mechanical and thermal stability, and record rotation speeds reaching up to 42 kHz (2.5 million revolutions per minute), these rotary nanomotors could advance technologies to meet a wide range of future nanomechanical and biomedical needs in fields such as nanorobotics, nanosurgery, DNA manipulation and nano/microfluidic flow control.

  12. Genomic evidence for plant-parasitic nematodes as the earliest Wolbachia hosts

    USDA-ARS?s Scientific Manuscript database

    Wolbachia, the most widely studied endosymbiont in arthropods, is a target for biological control of mosquito-borne diseases (malaria and dengue virus), and antibiotic elimination of infectious filarial nematodes. We sequenced and analyzed the genome of a new strain (wPpe) in the plant-parasitic nem...

  13. 77 FR 36331 - Noise Exposure Maps; Cleveland Hopkins International Airport, Cleveland, OH

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-18

    ... NEM graphics for flight tracks are presented in Figure 2, Jet Aircraft Radar and Model Tracks for...). Narrative discussion of the flight tracks is in Chapter 2, Development of Noise Contours, inclusive of... land use control and planning responsibilities of local government. These local responsibilities are...

  14. 40 CFR 799.1575 - Diethylenetriamine (DETA).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Center (NCIC) (7407), Office of Pollution Prevention and Toxics, U.S. Environmental Protection Agency... Center (NCIC) (7407), Office of Pollution Prevention and Toxics, U.S. Environmental Protection Agency...), Office of Pollution Prevention and Toxics, U.S. Environmental Protection Agency, Room B-607 NEM, 401 M St...

  15. REAL-TIME ENERGY INFORMATION AND CONSUMER BEHAVIOR: A META-ANALYSIS AND FORECAST

    EPA Science Inventory

    The meta-analysis of literature and program results will shed light on potential causes of study-to-study variation in information feedback programs and trials. Outputs from the meta-analysis, such as price elasticity, will be used in NEMS to estimate the impact of a nation...

  16. Carbon Nanofibers Synthesized on Selective Substrates for Nonvolatile Memory and 3D Electronics

    NASA Technical Reports Server (NTRS)

    Kaul, Anupama B.; Khan, Abdur R.

    2011-01-01

    . Currents up to approximately 100 nA could be cycled, which are likely to propagate via the tube surface, or sidewalls, rather than the body, which is shown by the I-V in figure (a). Electrical conduction via the sidewalls is a necessity for dc NEMS (nanoelectromechanical system) applications, more so than for the field emission applications of such tubes. During the tests, high conductivity was expected, because both probes were shorted to the substrate, as shown by curve 1 in the I-V characteristic in figure (b). When a tube grown on NbTiN was probed, the response was similar to the approximately equal to 100 nA and is represented by curve 2 in figure (b), which could be cycled and propagated via the tube surface or the sidewalls. However, no measureable currents for the tube grown directly on Si were observed as shown by curve 3 in figure (b), even after testing over a range of samples. This could arise from a dielectric coating on the sidewalls for tubes on Si. As a result of the directional nature of ion bombardment during dc PECVD, Si from the substrate is likely re-sputtered and possibly coats the sidewalls.

  17. Betavoltaic device in por-SiC/Si C-Nuclear Energy Converter

    NASA Astrophysics Data System (ADS)

    Akimchenko, Alina; Chepurnov, Victor; Dolgopolov, Mikhail; Gurskaya, Albina; Kuznetsov, Oleg; Mashnin, Alikhan; Radenko, Vitaliy; Radenko, Alexander; Surnin, Oleg; Zanin, George

    2017-10-01

    The miniature and low-power devices with long service life in hard operating conditions like the Carbon-14 beta-decay energy converters indeed as eternal resource for integrated MEMS and NEMS are considered. Authors discuss how to create the power supply for MEMS/NEMS devices, based on porous SiC/Si structure, which are tested to be used as the beta-decay energy converters of radioactive C-14 into electrical energy. This is based on the silicon carbide obtaining by self-organizing mono 3C-SiC endotaxy on the Si substrate. The new idea is the C-14 atoms including in molecules in the silicon carbide porous structure by this technology, which will increase the efficiency of the converter due to the greater intensity of electron-hole pairs generation rate in the space charge region. The synthesis of C-14 can be also performed by using the electronically controlled magneto-optic chamber.

  18. Relevance of Perpetrator Identity to Reporting Elder Financial and Emotional Mistreatment.

    PubMed

    Acierno, Ron; Steedley, Mara; Hernandez-Tejada, Melba A; Frook, Gabrielle; Watkins, Jordan; Muzzy, Wendy

    2018-04-01

    The National Elder Mistreatment Study (NEMS) found that 5.2% of community older adults experienced financial abuse, and 4.6% experienced emotional mistreatment in the past year. Unfortunately, the majority of abuse was not reported to the authorities. This study investigated reasons for non-reporting. In all, 774 NEMS participants were surveyed 8 years later via telephone to assess past-year financial and emotional mistreatment, perpetrator status, and whether any of these episodes were reported to authorities. In total, 87.5% of financial abuse by family, friends, or acquaintances was not reported versus 33% of that perpetrated by strangers; for emotional mistreatment, 89.9% of that perpetrated by family, friends, and acquaintances was not reported, compared with 83.3% by strangers. Reasons for non-reporting of emotional abuse centered largely around with "not wanting publicity" and "not wanting to get the perpetrator in trouble," while no consistent reason emerged for failure to report stranger-perpetrated mistreatment.

  19. A Multilevel Assessment of Barriers to Adoption of Dietary Approaches to Stop Hypertension (DASH) among African Americans of Low Socioeconomic Status

    PubMed Central

    Bertoni, Alain G.; Foy, Capri G.; Hunter, Jaimie C.; Quandt, Sara A.; Vitolins, Mara Z.; Whitt-Glover, Melicia C.

    2013-01-01

    Background We examined perceptions of Dietary Approaches to Stop Hypertension (DASH) and the food environment among African Americans (AA) with high blood pressure living in two low-income communities and objectively assessed local food outlets. Methods Focus groups were conducted with 30 AAs; participants discussed DASH and the availability of healthy foods in their community. Sessions were transcribed and themes identified. Fifty-four stores and 114 restaurants were assessed using the Nutrition Environment Measures Survey (NEMS). Results Common themes included poor availability, quality, and cost of healthy foods; tension between following DASH and feeding other family members; and lack of congruity between their preferred foods and DASH. Food outlets in majority AA census tracts had lower NEMS scores (stores: −11.7, p=.01, restaurants: −8.3, p=.001) compared with majority White areas. Conclusions Interventions promoting DASH among lower income AAs should reflect the food customs, economic concerns, and food available in communities. PMID:22080704

  20. [Evaluation of nurse workload in patients undergoing therapeutic hypothermia].

    PubMed

    Argibay-Lago, Ana; Fernández-Rodríguez, Diego; Ferrer-Sala, Nuria; Prieto-Robles, Cristina; Hernanz-del Río, Alexandre; Castro-Rebollo, Pedro

    2014-01-01

    Therapeutic hypothermia (TH) is recommended to minimize neurological damage in patients surviving sudden cardiac arrest (SCA). There is scarcity of data evaluating the nursing workload in these patients. The objective of the study is to assess the workload of nurses whilst treating patients undergoing TH after SCA. A 43-month prospective-retrospective comparative cohort study was designed. Patients admitted to intensive care unit, for recovered SCA and persistent coma, were included. A comparison was made using the baseline characteristics, medical management, in-hospital mortality, and nursing workload during the first 96hours using the Therapeutic Intervention Scoring System-28 (TISS-28); Nursing Activities Score (NAS); and Nine Equivalents of Nursing Manpower Use Score (NEMS) scales among patients who received TH and those who did not. A total 46 patients were included: 26 in the TH group and 20 in the Non-TH group. Regarding baseline characteristics and management, the TH group presented higher prevalence of smoking habit (69 vs. 25%, p=0.012), out-of-hospital SCA (96 vs. 55%, p<0.001), and the performance of coronary angiography (96 vs. 65%, p=0.014) compared with the non-TH group. No differences were observed in the nursing workload, assessed by TISS 28, NAS or NEMS scales, or in-hospital mortality. In this study performance of TH in SCA survivors is not associated with an increase in nursing workload. The installation of a TH program does not require the use of more nursing resources in terms of workload. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

  1. RovS and its associated signaling peptide form a cell-to-cell communication system required for Streptococcus agalactiae pathogenesis.

    PubMed

    Pérez-Pascual, David; Gaudu, Philippe; Fleuchot, Betty; Besset, Colette; Rosinski-Chupin, Isabelle; Guillot, Alain; Monnet, Véronique; Gardan, Rozenn

    2015-01-20

    Bacteria can communicate with each other to coordinate their biological functions at the population level. In a previous study, we described a cell-to-cell communication system in streptococci that involves a transcriptional regulator belonging to the Rgg family and short hydrophobic peptides (SHPs) that act as signaling molecules. Streptococcus agalactiae, an opportunistic pathogenic bacterium responsible for fatal infections in neonates and immunocompromised adults, has one copy of the shp/rgg locus. The SHP-associated Rgg is called RovS in S. agalactiae. In this study, we found that the SHP/RovS cell-to-cell communication system is active in the strain NEM316 of S. agalactiae, and we identified different partners that are involved in this system, such as the Eep peptidase, the PptAB, and the OppA1-F oligopeptide transporters. We also identified a new target gene controlled by this system and reexamined the regulation of a previously proposed target gene, fbsA, in the context of the SHP-associated RovS system. Furthermore, our results are the first to indicate the SHP/RovS system specificity to host liver and spleen using a murine model, which demonstrates its implication in streptococci virulence. Finally, we observed that SHP/RovS regulation influences S. agalactiae's ability to adhere to and invade HepG2 hepatic cells. Hence, the SHP/RovS cell-to-cell communication system appears to be an essential mechanism that regulates pathogenicity in S. agalactiae and represents an attractive target for the development of new therapeutic strategies. Rgg regulators and their cognate pheromones, called small hydrophobic peptides (SHPs), are present in nearly all streptococcal species. The general pathways of the cell-to-cell communication system in which Rgg and SHP take part are well understood. However, many other players remain unidentified, and the direct targets of the system, as well as its link to virulence, remain unclear. Here, we identified the different players

  2. FURTHER REFINEMENTS AND TESTING OF APEX3.0: EPA'S POPULATION EXPOSURE MODEL FOR CRITERIA AND AIR TOXIC INHALATION

    EPA Science Inventory

    The Air Pollutants Exposure Model (APEX(3.0)) is a PC-based model that was derived from the probabilistic NAAQS Exposure Model for carbon monoxide (pNEM/CO). APEX will be one of the tools used to estimate human population exposure for criteria and air toxic pollutants as part ...

  3. ASSESSING A COMPUTER MODEL FOR PREDICTING HUMAN EXPOSURE TO PM2.5

    EPA Science Inventory

    This paper compares outputs of a model for predicting PM2.5 exposure with experimental data obtained from exposure studies of selected subpopulations. The exposure model is built on a WWW platform called pCNEM, "A PC Version of pNEM." Exposure models created by pCNEM are sim...

  4. Ergovaline disappearance from a ruminally incubated buffer

    USDA-ARS?s Scientific Manuscript database

    Ergovaline (ERV) is an alkaloid present in endophyte-infected tall fescue (Lolium arundinaceum) that is thought to contribute to fescue toxicosis in cattle. To determine the disappearance of ERV in the temporarily washe reticulorumen, steer (n=8) were pair-fed alfalfa cubes at 1.5× NEM and received ...

  5. Seasonal variability of chlorophyll-a and oceanographic conditions in Sabah waters in relation to Asian monsoon--a remote sensing study.

    PubMed

    Abdul-Hadi, Alaa; Mansor, Shattri; Pradhan, Biswajeet; Tan, C K

    2013-05-01

    A study was conducted to investigate the influence of Asian monsoon on chlorophyll-a (Chl-a) content in Sabah waters and to identify the related oceanographic conditions that caused phytoplankton blooms at the eastern and western coasts of Sabah, Malaysia. A series of remote sensing measurements including surface Chl-a, sea surface temperature, sea surface height anomaly, wind speed, wind stress curl, and Ekman pumping were analyzed to study the oceanographic conditions that lead to large-scale nutrients enrichment in the surface layer. The results showed that the Chl-a content increased at the northwest coast from December to April due to strong northeasterly wind and coastal upwelling in Kota Kinabalu water. The southwest coast (Labuan water) maintained high concentrations throughout the year due to the effect of Padas River discharge during the rainy season and the changing direction of Baram River plume during the northeast monsoon (NEM). However, with the continuous supply of nutrients from the upwelling area, the high Chl-a batches were maintained at the offshore water off Labuan for a longer time during NEM. On the other side, the northeast coast illustrated a high Chl-a in Sandakan water during NEM, whereas the northern tip off Kudat did not show a pronounced change throughout the year. The southeast coast (Tawau water) was highly influenced by the direction of the surface water transport between the Sulu and Sulawesi Seas and the prevailing surface currents. The study demonstrates the presence of seasonal phytoplankton blooms in Sabah waters which will aid in forecasting the possible biological response and could further assist in marine resource managements.

  6. [Analysis of the workload and the use of the nursing resources in an intensive care unit].

    PubMed

    Valls-Matarín, J; Salamero-Amorós, M; Roldán-Gil, C

    2015-01-01

    To evaluate and assess the nursing workload (NW) scales by means of three scales and to determine the theoretical and real nurse/patient relationship in a polyvalent ICU. Cross-sectional descriptive study between July 2012 and June 2013 in patients over 18 years old, for which 3 nurses quantified, in randomized days, the NW by the Nursing Activities Score (NAS), Nine Equivalents Manpower Score (NEMS) and Valoración de Cargas de Trabajo y Tiempos de Enfermería (VACTE). Efficiency parameters of nursing resources were calculated: "work utilization ratio" (WUR), "level of care" operative (LOCop) and planned (LOCp). Data on demographics, length of stay and number of nurses were collected. 720 records were collected. The mean age was 64 (13.6) years. 73% were male and the median of length of stay was 3 (1-12) days. 60% were admitted for medical causes. The average total score was: NAS: 696.8 (111.6), NEMS: 311.8 (55.3) and VACTE: 4,978 (897.7). The required number of nurses according to NAS was 7 and 6,7 according to NEMS and VACTE. The actual average was 5.5. On all 3 scales the WUR was >1 and LOCop was 1.6 pacients/nurse. The LOCp was 2 patients/nurse. Assessing NW allows to know the reality of each unit. According to the scales and efficiency parameters of the nursing resources used, there is a shortage of nurses in relation to the work generated. NAS reflects more parameters of NW. Copyright © 2014 Elsevier España, S.L.U. y SEEIUC. All rights reserved.

  7. Urban food environments and residents' shopping behaviors.

    PubMed

    Cannuscio, Carolyn C; Tappe, Karyn; Hillier, Amy; Buttenheim, Alison; Karpyn, Allison; Glanz, Karen

    2013-11-01

    Food environments may promote or undermine healthy behaviors, but questions remain regarding how individuals interact with their local food environments. This study incorporated an urban food environment audit as well as an examination of residents' food shopping behaviors within that context. In 2010, the research team audited the variety and healthfulness of foods available in 373 Philadelphia stores, using the validated Nutrition Environment Measures Survey in Stores (NEMS-S); higher scores indicate more diverse and healthful food inventories. The team also surveyed urban residents (n=514) regarding their food shopping. Descriptive and multivariate analyses (conducted in 2012) assessed variation in retail food environments and in shoppers' store choices. Corner and convenience stores were common (78.6% of food retail outlets) and had the lowest mean NEMS-S scores of any store type. Most participants (94.5%) did their primary food shopping at higher-scoring chain supermarkets, and the majority of participants did not shop at the supermarket closest to home. Supermarket offerings varied, with significantly fewer healthful foods at supermarkets closest to the homes of disadvantaged residents. In multivariate analyses, participants were significantly more likely to shop at supermarkets closest to home if those supermarkets had higher NEMS-S scores. These data suggest that, when possible, shoppers chose supermarkets that offered more variety and more healthful foods. Findings from this study also reinforce concern regarding unhealthy immediate food environments for disadvantaged residents, who disproportionately relied on nearby stores with more limited food items. Interventions to improve nutrition and health should address not only food store proximity but also diversity of healthful foods available. © 2013 American Journal of Preventive Medicine.

  8. Reach‐scale river metabolism across contrasting sub‐catchment geologies: Effect of light and hydrology

    PubMed Central

    Attard, Karl M.; Binley, Andrew; Heppell, Catherine M.; Stahl, Henrik; Trimmer, Mark; Glud, Ronnie N.

    2017-01-01

    Abstract We investigated the seasonal dynamics of in‐stream metabolism at the reach scale (∼ 150 m) of headwaters across contrasting geological sub‐catchments: clay, Greensand, and Chalk of the upper River Avon (UK). Benthic metabolic activity was quantified by aquatic eddy co‐variance while water column activity was assessed by bottle incubations. Seasonal dynamics across reaches were specific for the three types of geologies. During the spring, all reaches were net autotrophic, with rates of up to 290 mmol C m−2 d−1 in the clay reach. During the remaining seasons, the clay and Greensand reaches were net heterotrophic, with peak oxygen consumption of 206 mmol m−2 d−1 during the autumn, while the Chalk reach was net heterotrophic only in winter. Overall, the water column alone still contributed to ∼ 25% of the annual respiration and primary production in all reaches. Net ecosystem metabolism (NEM) across seasons and reaches followed a general linear relationship with increasing stream light availability. Sub‐catchment specific NEM proved to be linearly related to the local hydrological connectivity, quantified as the ratio between base flow and stream discharge, and expressed on a timescale of 9 d on average. This timescale apparently represents the average period of hydrological imprint for carbon turnover within the reaches. Combining a general light response and sub‐catchment specific base flow ratio provided a robust functional relationship for predicting NEM at the reach scale. The novel approach proposed in this study can help facilitate spatial and temporal upscaling of riverine metabolism that may be applicable to a broader spectrum of catchments. PMID:29242670

  9. Purcell effect for active tuning of light scattering from semiconductor optical antennas.

    PubMed

    Holsteen, Aaron L; Raza, Søren; Fan, Pengyu; Kik, Pieter G; Brongersma, Mark L

    2017-12-15

    Subwavelength, high-refractive index semiconductor nanostructures support optical resonances that endow them with valuable antenna functions. Control over the intrinsic properties, including their complex refractive index, size, and geometry, has been used to manipulate fundamental light absorption, scattering, and emission processes in nanostructured optoelectronic devices. In this study, we harness the electric and magnetic resonances of such antennas to achieve a very strong dependence of the optical properties on the external environment. Specifically, we illustrate how the resonant scattering wavelength of single silicon nanowires is tunable across the entire visible spectrum by simply moving the height of the nanowires above a metallic mirror. We apply this concept by using a nanoelectromechanical platform to demonstrate active tuning. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  10. High-frequency electromechanical resonators based on thin GaTe

    NASA Astrophysics Data System (ADS)

    Chitara, Basant; Ya'akobovitz, Assaf

    2017-10-01

    Gallium telluride (GaTe) is a layered material, which exhibits a direct bandgap (˜1.65 eV) regardless of its thickness and therefore holds great potential for integration as a core element in stretchable optomechanical and optoelectronic devices. Here, we characterize and demonstrate the elastic properties and electromechanical resonators of suspended thin GaTe nanodrums. We used atomic force microscopy to extract the Young’s modulus of GaTe (average value ˜39 GPa) and to predict the resonance frequencies of suspended GaTe nanodrums of various geometries. Electromechanical resonators fabricated from suspended GaTe revealed fundamental resonance frequencies in the range of 10-25 MHz, which closely match predicted values. Therefore, this study paves the way for creating a new generation of GaTe based nanoelectromechanical devices with a direct bandgap vibrating element, which can serve as optomechanical sensors and actuators.

  11. 77 FR 50759 - Noise Exposure Map Notice, Orlando Sanford International Airport, Sanford, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-22

    ...; Table 13: 2009 and 2016 Local Runway Use Percentages; Figure 1: East Flow Flight Tracks; Figure 2: West Flow Flight Tracks; Figure 3: Local Flight Tracks; Figure 4: Existing Land Use; Figure 5: 2011 NEM... inseparable from the ultimate land use control and planning responsibilities of local government. These local...

  12. Natural hybridization and genetic and morphological variation between two epiphytic bromeliads

    PubMed Central

    Neri, Jordana; Wendt, Tânia

    2018-01-01

    Abstract Reproductive isolation is of fundamental importance for maintaining species boundaries in sympatry. Here, we examine the genetic and morphological differences between two closely related bromeliad species: Vriesea simplex and Vriesea scalaris. Furthermore, we examined the occurrence of natural hybridization and discuss the action of reproductive isolation barriers. Nuclear genomic admixture suggests hybridization in sympatric populations, although interspecific gene flow is low among species in all sympatric zones (Nem < 0.5). Thus, morphological and genetic divergence (10.99 %) between species can be maintained despite ongoing natural hybridization. Cross-evaluation of our genetic and morphological data suggests that species integrity is maintained by the simultaneous action of multiple barriers, such as divergent reproductive systems among species, differences in floral traits and low hybrid seed viability. PMID:29308124

  13. Links between contaminant hotspots in low flow estuarine systems and altered sediment biogeochemical processes

    NASA Astrophysics Data System (ADS)

    Sutherland, Michael D.; Dafforn, Katherine A.; Scanes, Peter; Potts, Jaimie; Simpson, Stuart L.; Sim, Vivian X. Y.; Johnston, Emma L.

    2017-11-01

    The urbanisation of coastal zones is a major threat to the health of global estuaries and has been linked to increased contamination (e.g. metals) and excess organic matter. Urban stormwater networks collect and funnel contaminants into waterways at point sources (e.g. stormdrains). Under dry, low flow conditions, these stormwater contaminants can accumulate in sediments over time and result in modifications to benthic sediment biogeochemical processes. To quantify these processes, this field study measured differences in benthic metabolism (CR, GPP, NEM) and sediment-water nutrient fluxes (NH3, NOx, PO4) associated with stormdrains (0 m, 200 m and 1000 m away) and increased water-retention (embayments vs channels). Significant changes to benthic metabolism were detected with distance from stormdrains, and with differences in water-retention rates, above natural spatial and temporal variation. Oxygen consumption was ∼50% higher at stormdrains (0 m) compared to 1000 m away and >70% higher at stormdrains (0 m) located in embayments compared to channels. Oxygen production also appeared to decrease with distance from stormdrains in embayments, but patterns were variable. These changes to benthic metabolism were of a magnitude expected to influence benthic nutrient cycling, but NH3, NOx and PO4 fluxes were generally low, and highly spatially and temporally variable. Overall, metal (Cu) contamination explained most of the variation in sediment biogeochemical processes between embayments and channels, while sediment grain size explained differences in fluxes with distance from stormdrains. Importantly, although there was evidence of increased productivity associated with stormdrains, we also detected evidence of early hypoxia suggesting that systems with legacy stormwater contaminants exist on a tipping point. Future work should investigate changes to sediment processes after a major rainfall event, when large and sudden inputs of potentially toxic contaminants occur

  14. Nanocomposite films

    DOEpatents

    Mitlin, David; , Ophus, Colin; Evoy, Stephane; Radmilovic, Velimir; Mohammadi, Reza; Westra, Ken; Nelson-Fitzpatrick, Nathaniel; Lee, Zonghoon

    2010-07-20

    A thin-film composition of nanocrystal molybdenum in an amorphous metallic matrix may be formed by co-sputtering Mo with aluminum or nickel. NEMS cantilevers may be formed from the film. The films exhibit high nanoindentation hardness and a reduction in roughness and intrinsic stress, while maintaining resistivity in the metallic range.

  15. Ergot alkaloids decrease rumen epithelial blood flow

    USDA-ARS?s Scientific Manuscript database

    Two experiments were conducted to determine if ergot alkaloids affect blood flow to the absorptive surface of the rumen of steers. Steers (n=8 total) were pair-fed alfalfa cubes at 1.5× NEM and received ground endophyte-infected tall fescue seed (E+) or endophyte-free tall fescue seed (E-) via rumen...

  16. Fabrication technology of CNT-Nickel Oxide based planar pseudocapacitor for MEMS and NEMS

    NASA Astrophysics Data System (ADS)

    Lebedev, E. A.; Kitsyuk, E. P.; Gavrilin, I. M.; Gromov, D. G.; Gruzdev, N. E.; Gavrilov, S. A.; Dronov, A. A.; Pavlov, A. A.

    2015-11-01

    Fabrication technology of planar pseudocapacitor (PsC) based on carbon nanotube (CNT) forest, synthesized using plasma enhanced chemical vapor deposition (PECVD) method, covered with thin nickel oxide layer deposited by successive ionic layer adsorption and reaction (SILAR) method, is demonstrated. Dependences of deposited oxide layers thickness on device specific capacities is studied. It is shown that pseudocapacity of nickel oxide thin layer increases specific capacity of the CNT's based device up to 2.5 times.

  17. Multiple Rapid Swallow Maneuver Enhances the Clinical Utility of High-Resolution Manometry in Patients Showing Ineffective Esophageal Motility

    PubMed Central

    Min, Yang Won; Shin, Inseub; Son, Hee Jung; Rhee, Poong-Lyul

    2015-01-01

    Abstract The clinical significance of ineffective esophageal motility (IEM) together with multiple rapid swallow (MRS) has not been yet evaluated in the Chicago Classification v3.0. This study evaluated the adjunctive role of MRS in IEM and determined the criteria of abnormal MRS to maximize the utility of IEM. We analyzed 186 patients showing IEM or normal esophageal motility (NEM), who underwent esophageal high-resolution impedance–manometry for esophageal symptoms. Two different criteria for abnormal MRS were applied to IEM subjects, resulting in 2 corresponding subgroups: IEM-A when distal contractile integral (DCI) ratio between an average wet swallows and MRS contraction was <1 and IEM-B when MRS contraction DCI was <450 mm Hg-s-cm. One IEM subject inadequately performed MRS. Among the remaining 52 IEM subjects, 18 (34.6%) were classified into IEM-A and 23 (44.2%) into IEM-B. IEM subjects showed less complete bolus transit (median 0.0%, interquartile range 0.0–20.0% vs 60.0%, 30.0–80.0; P < 0.001) resulting in higher impaired bolus transit than NEM subjects (98.1% vs 66.9%, P = 0.001). IEM-B subjects showed additionally higher pathologic bolus exposure than NEM subjects (55.6% vs 29.3%, P = 0.001), whereas IEM-A subjects could not. Although IEM-B subjects had the highest prevalence of gastroesophageal reflux disease among the subjects groups, it did not reach statistical significance. In conclusion, IEM patients with abnormal MRS contraction have an increased risk of prolonged bolus clearance, poor bolus transit, and pathologic bolus exposure. IEM patients need to be assessed concerning whether MRS contraction DCI is <450 mm Hg-s-cm to segregate clinically relevant patients. PMID:26448010

  18. Assessment of food offerings and marketing strategies in the food-service venues at California Children's Hospitals.

    PubMed

    Lesser, Lenard I; Hunnes, Dana E; Reyes, Phedellee; Arab, Lenore; Ryan, Gery W; Brook, Robert H; Cohen, Deborah A

    2012-01-01

    Marketing strategies and food offerings in hospital cafeterias can impact dietary choices. Using a survey adapted to assess food environments, the purpose of this study was to assess the food environment available to patients, staff, and visitors at the food-service venues in all 14 California children's hospitals. We modified a widely-used tool to create the Nutritional Environment Measures Survey for Cafeterias (NEMS-C) by partnering with a hospital wellness committee. The NEMS-C summarizes the number of healthy items offered, whether calorie labeling is present, if there is signage promoting healthy or unhealthy foods, pricing structure, and the presence of unhealthy combination meals. The range of possible scores is zero (unhealthy) to 37 (healthy). We directly observed the food-service venues at all 14 tertiary care children's hospitals in California and scored them. Inter-rater reliability showed 89% agreement on the assessed items. For the 14 hospitals, the mean score was 19.1 (SD = 4.2; range, 13-30). Analysis revealed that nearly all hospitals offered diet drinks, low-fat milk, and fruit. Fewer than one-third had nutrition information at the point of purchase and 30% had signs promoting healthy eating. Most venues displayed high calorie impulse items such as cookies and ice cream at the registers. Seven percent (7%) of the 384 entrees served were classified as healthy according to NEMS criteria. Most children's hospitals' food venues received a mid-range score, demonstrating there is considerable room for improvement. Many inexpensive options are underused, such as providing nutritional information, incorporating signage that promotes healthy choices, and not presenting unhealthy impulse items at the register. Copyright © 2012 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

  19. Composition Comprising Silicon Carbide

    NASA Technical Reports Server (NTRS)

    Mehregany, Mehran (Inventor); Zorman, Christian A. (Inventor); Fu, Xiao-An (Inventor); Dunning, Jeremy L. (Inventor)

    2012-01-01

    A method of depositing a ceramic film, particularly a silicon carbide film, on a substrate is disclosed in which the residual stress, residual stress gradient, and resistivity are controlled. Also disclosed are substrates having a deposited film with these controlled properties and devices, particularly MEMS and NEMS devices, having substrates with films having these properties.

  20. Silicon carbide and other films and method of deposition

    NASA Technical Reports Server (NTRS)

    Mehregany, Mehran (Inventor); Zorman, Christian A. (Inventor); Fu, Xiao-An (Inventor); Dunning, Jeremy L. (Inventor)

    2007-01-01

    A method of depositing a ceramic film, particularly a silicon carbide film, on a substrate is disclosed in which the residual stress, residual stress gradient, and resistivity are controlled. Also disclosed are substrates having a deposited film with these controlled properties and devices, particularly MEMS and NEMS devices, having substrates with films having these properties.

  1. Silicon carbide and other films and method of deposition

    NASA Technical Reports Server (NTRS)

    Mehregany, Mehran (Inventor); Zorman, Christian A. (Inventor); Fu, Xiao-An (Inventor); Dunning, Jeremy (Inventor)

    2011-01-01

    A method of depositing a ceramic film, particularly a silicon carbide film, on a substrate is disclosed in which the residual stress, residual stress gradient, and resistivity are controlled. Also disclosed are substrates having a deposited film with these controlled properties and devices, particularly MEMS and NEMS devices, having substrates with films having these properties.

  2. Effects of Ohmic Resistance on Dynamic Characteristics and Impedance of Micro/Nano Cantilever Beam resonators

    NASA Astrophysics Data System (ADS)

    Rezazadeh, Ghader; Keyvani, Aliasghar; Sadeghi, Morteza H.; Bahrami, Manouchehr

    2013-06-01

    Effects of Ohmic resistance on MEMS/NEMS vibrating structures that have always been dismissed in some situations may cause important changes in resonance properties and impedance parameters of the MEMS/NEMS based circuits. In this paper it is aimed to present a theoretical model to precisely investigate the problem on a simple cantilever-substrate resonator. In this favor the Ohm's current law and charge conservation law have been merged to find a differential Equation for voltage propagation on the beam and because mostly nano structures are expected as the scope of the problem, modified couple stress theory is used to formulate the dynamic motion of the beam. The two governing equations were coupled and both nonlinear that have been solved simultaneously using a Galerkin based state space formulation. The obtained results that are in exact agreement with previous works show that dynamic pull-in voltage, switching time, and impedance of structure as a MEMS capacitor especially in frequencies higher than natural resonance frequency strongly relay on electrical resistance of the beam and substrate material.

  3. Two Surface Temperature Retrieval Methods Compared Over Agricultural Lands

    NASA Technical Reports Server (NTRS)

    French, Andrew N.; Schmugge, Thomas J.; Jacob, Frederic; Ogawa, Kenta; Houser, Paul R. (Technical Monitor)

    2002-01-01

    Accurate, spatially distributed surface temperatures are required for modeling evapotranspiration (ET) over agricultural fields under wide ranging conditions, including stressed and unstressed vegetation. Modeling approaches that use surface temperature observations, however, have the burden of estimating surface emissivities. Emissivity estimation, the subject of much recent research, is facilitated by observations in multiple thermal infrared bands. But it is nevertheless a difficult task. Using observations from a multiband thermal sensor, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), estimated surface emissivities and temperatures are retrieved in two different ways: the temperature emissivity separation approach (TES) and the normalized emissivity approach (NEM). Both rely upon empirical relationships, but the assumed relationships are different. TES relies upon a relationship between the minimum spectral emissivity and the range of observed emissivities. NEM relies upon an assumption that at least one thermal band has a pre-determined emissivity (close to 1.0). The benefits and consequences of each approach will be demonstrated for two different landscapes: one in central Oklahoma, USA and another in southern New Mexico.

  4. Air-bridge and Vertical CNT Switches for High Performance Switching Applications

    NASA Technical Reports Server (NTRS)

    Kaul, Anupama B.; Wong, Eric W.; Epp, Larry; Bronikowski, Michael J.; Hunt, BBrian D.

    2006-01-01

    Carbon nanotubes are attractive for switching applications since electrostatically-actuated CNT switches have low actuation voltages and power requirements, while allowing GHz switching speeds that stem from the inherently high elastic modulus and low mass of the CNT.Our first NEM structure, the air-bridge switch, consists of suspended single-walled nanotubes (SWNTs) that lie above a sputtered Nb base electrode, where contact to the CNTs is made using evaporated Au/Ti. Electrical measurements of these air-bridge devices show well-defined ON and OFF states as a dc bias of a few volts is applied between the CNT and the Nb-base electrode. The CNT air-bridge switches were measured to have switching times down to a few nanoseconds. Our second NEM structure, the vertical CNT switch, consists of nanotubes grown perpendicular to the substrate. Vertical multi-walled nanotubes (MWNTs) are grown directly on a heavily doped Si substrate, from 200 - 300 nm wide, approximately 1 micrometer deep nano-pockets, with Nb metal electrodes to result in the formation of a vertical single-pole-double-throw switch architecture.

  5. Electromechanical quantum simulators

    NASA Astrophysics Data System (ADS)

    Tacchino, F.; Chiesa, A.; LaHaye, M. D.; Carretta, S.; Gerace, D.

    2018-06-01

    Digital quantum simulators are among the most appealing applications of a quantum computer. Here we propose a universal, scalable, and integrated quantum computing platform based on tunable nonlinear electromechanical nano-oscillators. It is shown that very high operational fidelities for single- and two-qubits gates can be achieved in a minimal architecture, where qubits are encoded in the anharmonic vibrational modes of mechanical nanoresonators, whose effective coupling is mediated by virtual fluctuations of an intermediate superconducting artificial atom. An effective scheme to induce large single-phonon nonlinearities in nanoelectromechanical devices is explicitly discussed, thus opening the route to experimental investigation in this direction. Finally, we explicitly show the very high fidelities that can be reached for the digital quantum simulation of model Hamiltonians, by using realistic experimental parameters in state-of-the-art devices, and considering the transverse field Ising model as a paradigmatic example.

  6. Surface-Induced Near-Field Scaling in the Knudsen Layer of a Rarefied Gas

    NASA Astrophysics Data System (ADS)

    Gazizulin, R. R.; Maillet, O.; Zhou, X.; Cid, A. Maldonado; Bourgeois, O.; Collin, E.

    2018-01-01

    We report on experiments performed within the Knudsen boundary layer of a low-pressure gas. The noninvasive probe we use is a suspended nanoelectromechanical string, which interacts with He 4 gas at cryogenic temperatures. When the pressure P is decreased, a reduction of the damping force below molecular friction ∝P had been first reported in Phys. Rev. Lett. 113, 136101 (2014), 10.1103/PhysRevLett.113.136101 and never reproduced since. We demonstrate that this effect is independent of geometry, but dependent on temperature. Within the framework of kinetic theory, this reduction is interpreted as a rarefaction phenomenon, carried through the boundary layer by a deviation from the usual Maxwell-Boltzmann equilibrium distribution induced by surface scattering. Adsorbed atoms are shown to play a key role in the process, which explains why room temperature data fail to reproduce it.

  7. Free energy barrier for molecular motions in bistable [2]rotaxane molecular electronic devices.

    PubMed

    Kim, Hyungjun; Goddard, William A; Jang, Seung Soon; Dichtel, William R; Heath, James R; Stoddart, J Fraser

    2009-03-12

    Donor-acceptor binding of the pi-electron-poor cyclophane cyclobis(paraquat-p-phenylene) (CBPQT(4+)) with the pi-electron-rich tetrathiafulvalene (TTF) and 1,5-dioxynaphthalene (DNP) stations provides the basis for electrochemically switchable, bistable [2]rotaxanes, which have been incorporated and operated within solid-state devices to form ultradense memory circuits (ChemPhysChem 2002, 3, 519-525; Nature 2007, 445, 414-417) and nanoelectromechanical systems. The rate of CBPQT(4+) shuttling at each oxidation state of the [2]rotaxane dictates critical write-and-retention time parameters within the devices, which can be tuned through chemical synthesis. To validate how well computational chemistry methods can estimate these rates for use in designing new devices, we used molecular dynamics simulations to calculate the free energy barrier for the shuttling of the CBPQT(4+) ring between the TTF and the DNP. The approach used here was to calculate the potential of mean force along the switching pathway, from which we calculated free energy barriers. These calculations find a turn-on time after the rotaxane is doubly oxidized of approximately 10(-7) s (suggesting that the much longer experimental turn-on time is determined by the time scale of oxidization). The return barrier from the DNP to the TTF leads to a predicted lifetime of 2.1 s, which is compatible with experiments.

  8. A mobile Sn nanowire inside a β-Ga2 O3 tube: a practical nanoscale electrically/thermally driven switch.

    PubMed

    Zou, Rujia; Zhang, Zhenyu; Tian, Qiwei; Ma, Guanxing; Song, Guosheng; Chen, Zhigang; Hu, Junqing

    2011-12-02

    Nanoelectromechanical system switches are seen as key devices for fast switching in communication networks since they can be switched between transmitting and receiving states with an electrostatic command. Herein, the fabrication of practical, nanoscale electrically/thermally driven switches is reported based on a mobile Sn nanowire inside a β-Ga2 O3 tube. The melting point of Sn inside the Ga2 O3 tube is found to be as low as 58 °C-far below the value of bulk Sn (231.89 °C)-and its crystal phase (β-Sn) remains unchanged even at temperatures as low as -170 °C. Thus a miniaturization of the unique wide-temperature-range thermometer based on the linear thermal expansion of liquid Sn fillings in the Ga2 O3 tube is realized. In addition, the electrical properties of the Sn-nanowire-filled β-Ga2 O3 tubes are carefully determined: importantly, the resistance demonstrates a sudden drop (rise) when two Sn nanowires contact (separate), due to the thermally driven motion of the liquid Sn fillings inside the tube. Thus this structure can be switched between its on and off states by controlling the motion, merging or splitting, of the Sn nanowires inside the tube, either electrically, by applying a current, or thermally, at a predetermined temperature. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. National Dam Safety Program. Lipps Lake Dam (MO 30214). Mississippi - Kaskaskia - St. Louis Basin, Cape Girardeau County, Missouri. Phase I Inspection Report.

    DTIC Science & Technology

    1980-10-01

    AD-A105 988 HOSKINSEWESTERN-SONOER EGGER INC LINCOLN NEM F/S 13/13 NATIONAL DA -M SAFETY PROGRAM. LI PS LAKE DAM (MO 3021 ). MISS! SS7 - TC(U...COMPLETING FORM i. REPORT NUMBER 12. GOVT ACCESSION NO. 3. RECIPIENT’S CATALOG NIOMBER 4. TITLE (and Subtitle) 5. TYPE OF REPORT & PERIOD COVERED Phase I Dam

  10. 78 FR 25523 - Acceptance of Noise Exposure Map Notice for Oakland County International Airport, Pontiac, Michigan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-01

    ... Utilization, Table D5, Runway Utilization By Category of Aircraft; Figure D3, INM Flight Tracks, West Flow, Figure D4, INM Flight Tracks, East Flow. The Future NEM is located in Figure D6, Future Noise Exposure... Assumptions for Future Conditions, 2021. The Flight Tracks depicted in Figure D3, INM Flight Tracks, West Flow...

  11. Warning: potential problems for taxonomy on the horizon?

    PubMed

    Cianferoni, Fabio; Bartolozzi, Luca

    2016-07-19

    Whether or not a species might reasonably be described without the preservation of a type specimen is a matter of ongoing discussion among taxonomists (Dubois & Nemésio 2007; Minteer et al. 2014; Krell & Wheeler 2014; Löbl et al. 2016; Marshall & Evenhuis 2016; Santos et al. 2016). Here, we attempt to make our own contribution to the topic.

  12. Explicit Knowledge of the Spanish Subjunctive and Accurate Use in Discrete-Point, Oral Production, and Written Production Measures

    ERIC Educational Resources Information Center

    Gutiérrez, Xavier

    2017-01-01

    The usefulness of explicit knowledge of the second language is a matter of controversy in the field of second language acquisition. In this regard, it has been argued that explicit representations might be useful for some structures but not for others (R. Ellis, 2006; Roehr & Gánem-Gutiérrez, 2009). The goal of this study was to examine…

  13. 78 FR 21125 - Findings of Research Misconduct

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-09

    ... to the following publications and grant applications: Blood pre-published online on January 16, 2003 (``NEM'') Experimental Hematology 31:372-381, 2003 (``CMA'') Blood 97:147-153, 2001 (``ISB'') R01 CA89135-01A1 R01 HL73063-01 R01 HL79615-01 Blood pre-published online on January 16, 2003, has been retracted...

  14. Evaluation, Sustainable Development, and the Environment in the South Pacific

    ERIC Educational Resources Information Center

    Turvey, Rosario

    2007-01-01

    This article outlines the Results-Based Evaluation (RBE) framework proposed for the ex-post assessment of the National Environmental Management Strategies (NEMS) in 12 small-island developing states (SIDS) in the South Pacific. It gives an overview of the methods and basis of developing an evaluation framework in the context of SIDS in the region.…

  15. Application of washed rumen technique for rapid determination of fasting heat production in steers

    USDA-ARS?s Scientific Manuscript database

    Two experiments were conducted to evaluate the use of a washed rumen technique as an alternative approach for determining fasting HP in cattle. In Exp. 1, 8 Holstein steers (322±30 kg) were adapted to a cubed alfalfa-based diet (1.5xNEm) for 10 d. After which steers were placed into individual hea...

  16. Free-standing nanomechanical and nanophotonic structures in single-crystal diamond

    NASA Astrophysics Data System (ADS)

    Burek, Michael John

    inventory of luminescent defect centers (many with direct optical access to highly coherent electron and nuclear spins). Diamond has many potential applications ranging from radio frequency nanoelectromechanical systems (RF-NEMS), to all-optical signal processing and quantum optics. Despite the commercial availability of wafer-scale nanocrystalline diamond thin films on foreign substrates (namely SiO2), this diamond-on-insulator (DOI) platform typically exhibits inferior material properties due to friction, scattering, and absorption losses at grain boundaries, significant surface roughness, and large interfacial stresses. In the absence of suitable heteroepitaxial diamond growth, substantial research and development efforts have focused on novel processing techniques to yield nanoscale single-crystal diamond mechanical and optical elements. In this thesis, we demonstrate a scalable 'angled-etching' nanofabrication method for realizing nanomechanical systems and nanophotonic networks starting from bulk single-crystal diamond substrates. Angled-etching employs anisotropic oxygen-based plasma etching at an oblique angle to the substrate surface, resulting in suspended optical structures with triangular cross-sections. Using this approach, we first realize single-crystal diamond nanomechanical resonant structures. These nanoscale diamond resonators exhibit high mechanical quality-factors (approaching Q ~ 105) with mechanical resonances up to 10 MHz. Next, we demonstrate engineered nanophotonic structures, specifically racetrack resonators and photonic crystal cavities, in bulk single-crystal diamond. Our devices feature large optical Q-factors, in excess of 10 5, and operate over a wide wavelength range, spanning visible and telecom. These newly developed high-Q diamond optical nanocavities open the door for a wealth of applications, ranging from nonlinear optics and chemical sensing, to quantum information processing and cavity optomechanics. Beyond isolated nanophotonic

  17. Carbon Nanotubes as FET Channel: Analog Design Optimization considering CNT Parameter Variability

    NASA Astrophysics Data System (ADS)

    Samar Ansari, Mohd.; Tripathi, S. K.

    2017-08-01

    Carbon nanotubes (CNTs), both single-walled as well as multi-walled, have been employed in a plethora of applications pertinent to semiconductor materials and devices including, but not limited to, biotechnology, material science, nanoelectronics and nano-electro mechanical systems (NEMS). The Carbon Nanotube Field Effect Transistor (CNFET) is one such electronic device which effectively utilizes CNTs to achieve a boost in the channel conduction thereby yielding superior performance over standard MOSFETs. This paper explores the effects of variability in CNT physical parameters viz. nanotube diameter, pitch, and number of CNT in the transistor channel, on the performance of a chosen analog circuit. It is further shown that from the analyses performed, an optimal design of the CNFETs can be derived for optimizing the performance of the analog circuit as per a given specification set.

  18. Compact nanomechanical plasmonic phase modulators [Ultracompact nano-mechanical plasmonic phase modulators

    DOE PAGES

    Dennis, B. S.; Haftel, M. I.; Czaplewski, D. A.; ...

    2015-03-30

    Highly confined optical energy in plasmonic devices is advancing miniaturization in photonics. However, for mode sizes approaching ≈10 nm, the energy increasingly shifts into the metal, raising losses and hindering active phase modulation. Here, we propose a nanoelectromechanical phase-modulation principle exploiting the extraordinarily strong dependence of the phase velocity of metal–insulator–metal gap plasmons on dynamically variable gap size. We experimentally demonstrate a 23-μm-long non-resonant modulator having a 1.5π rad range, with 1.7 dB excess loss at 780 nm. Analysis shows that by simultaneously decreasing the gap, length and width, an ultracompact-footprint π rad phase modulator can be realized. This ismore » achieved without incurring the extra loss expected for plasmons confined in a decreasing gap, because the increasing phase-modulation strength from a narrowing gap offsets rising propagation losses. Here, such small, high-density electrically controllable components may find applications in optical switch fabrics and reconfigurable plasmonic optics.« less

  19. Performance of monolayer graphene nanomechanical resonators with electrical readout.

    PubMed

    Chen, Changyao; Rosenblatt, Sami; Bolotin, Kirill I; Kalb, William; Kim, Philip; Kymissis, Ioannis; Stormer, Horst L; Heinz, Tony F; Hone, James

    2009-12-01

    The enormous stiffness and low density of graphene make it an ideal material for nanoelectromechanical applications. Here, we demonstrate the fabrication and electrical readout of monolayer graphene resonators, and test their response to changes in mass and temperature. The devices show resonances in the megahertz range, and the strong dependence of resonant frequency on applied gate voltage can be fitted to a membrane model to yield the mass density and built-in strain of the graphene. Following the removal and addition of mass, changes in both density and strain are observed, indicating that adsorbates impart tension to the graphene. On cooling, the frequency increases, and the shift rate can be used to measure the unusual negative thermal expansion coefficient of graphene. The quality factor increases with decreasing temperature, reaching approximately 1 x 10(4) at 5 K. By establishing many of the basic attributes of monolayer graphene resonators, the groundwork for applications of these devices, including high-sensitivity mass detectors, is put in place.

  20. Detection of quantum well induced single degenerate-transition-dipoles in ZnO nanorods.

    PubMed

    Ghosh, Siddharth; Ghosh, Moumita; Seibt, Michael; Rao, G Mohan

    2016-02-07

    Quantifying and characterising atomic defects in nanocrystals is difficult and low-throughput using the existing methods such as high resolution transmission electron microscopy (HRTEM). In this article, using a defocused wide-field optical imaging technique, we demonstrate that a single ultrahigh-piezoelectric ZnO nanorod contains a single defect site. We model the observed dipole-emission patterns from optical imaging with a multi-dimensional dipole and find that the experimentally observed dipole pattern and model-calculated patterns are in excellent agreement. This agreement suggests the presence of vertically oriented degenerate-transition-dipoles in vertically aligned ZnO nanorods. The HRTEM of the ZnO nanorod shows the presence of a stacking fault, which generates a localised quantum well induced degenerate-transition-dipole. Finally, we elucidate that defocused wide-field imaging can be widely used to characterise defects in nanomaterials to answer many difficult questions concerning the performance of low-dimensional devices, such as in energy harvesting, advanced metal-oxide-semiconductor storage, and nanoelectromechanical and nanophotonic devices.

  1. Developing ultrasensitive pressure sensor based on graphene nanoribbon: Molecular dynamics simulation

    NASA Astrophysics Data System (ADS)

    Kwon, Oh Kuen; Lee, Jun Ha; Kim, Ki-Sub; Kang, Jeong Won

    2013-01-01

    We propose schematics for an ultra-sensitive pressure sensor based on graphene-nanoribbon (GNR) and investigate its electromechanical properties using classical molecular dynamics simulations and piezo-electricity theory. Since the top plate applied to the actual pressure is large whereas the contact area on the GNR is very small, both the sensitivity and the sensing range can be adjusted by controlling the aspect ratio between the top plate and the contact point areas. Our calculation shows that the electrical conductivity of GNRs can be tuned by the applied pressure and the electric conductance of the deflected GNR linearly increases with increasing applied pressure for the linear elastic region in low pressure below the cut-off point. In the curves for both the deflection and potential energy, the linear elastic regime in low pressure was explicitly separated with the non-linear elastic regime in high pressure. The proposed GNR-based nanoelectromechanical devices have great potential for application as electromechanical memory, relay or switching devices.

  2. Electromechanics in MoS2 and WS2: nanotubes vs. monolayers

    PubMed Central

    Ghorbani-Asl, Mahdi; Zibouche, Nourdine; Wahiduzzaman, Mohammad; Oliveira, Augusto F.; Kuc, Agnieszka; Heine, Thomas

    2013-01-01

    The transition-metal dichalcogenides (TMD) MoS2 and WS2 show remarkable electromechanical properties. Strain modifies the direct band gap into an indirect one, and substantial strain even induces an semiconductor-metal transition. Providing strain through mechanical contacts is difficult for TMD monolayers, but state-of-the-art for TMD nanotubes. We show using density-functional theory that similar electromechanical properties as in monolayer and bulk TMDs are found for large diameter TMD single- (SWNT) and multi-walled nanotubes (MWNTs). The semiconductor-metal transition occurs at elongations of 16%. We show that Raman signals of the in-plane and out-of-plane lattice vibrations depend significantly and linearly on the strain, showing that Raman spectroscopy is an excellent tool to determine the strain of the individual nanotubes and hence monitor the progress of nanoelectromechanical experiments in situ. TMD MWNTs show twice the electric conductance compared to SWNTs, and each wall of the MWNTs contributes to the conductance proportional to its diameter. PMID:24129919

  3. Electrically driven quantum light emission in electromechanically tuneable photonic crystal cavities

    NASA Astrophysics Data System (ADS)

    Petruzzella, M.; Pagliano, F. M.; Zobenica, Ž.; Birindelli, S.; Cotrufo, M.; van Otten, F. W. M.; van der Heijden, R. W.; Fiore, A.

    2017-12-01

    A single quantum dot deterministically coupled to a photonic crystal environment constitutes an indispensable elementary unit to both generate and manipulate single-photons in next-generation quantum photonic circuits. To date, the scaling of the number of these quantum nodes on a fully integrated chip has been prevented by the use of optical pumping strategies that require a bulky off-chip laser along with the lack of methods to control the energies of nano-cavities and emitters. Here, we concurrently overcome these limitations by demonstrating electrical injection of single excitonic lines within a nano-electro-mechanically tuneable photonic crystal cavity. When an electrically driven dot line is brought into resonance with a photonic crystal mode, its emission rate is enhanced. Anti-bunching experiments reveal the quantum nature of these on-demand sources emitting in the telecom range. These results represent an important step forward in the realization of integrated quantum optics experiments featuring multiple electrically triggered Purcell-enhanced single-photon sources embedded in a reconfigurable semiconductor architecture.

  4. Spatial-temporal variation in orchid bee communities (Hymenoptera: Apidae) in remnants of arboreal Caatinga in the Chapada Diamantina region, state of Bahia, Brazil.

    PubMed

    Andrade-Silva, A C R; Nemésio, A; de Oliveira, F F; Nascimento, F S

    2012-08-01

    The spatial and temporal distribution of organisms is a fundamental aspect of biological communities. The present study focused on three remnants of arboreal Caatinga in northeastern Brazil between May, 2009 and April, 2010. A total of 627 euglossine males were captured in traps baited with artificial aromatic compounds. The specimens belonged to 14 species and four genera: Euglossa Latreille, Eulaema Lepeletier, Eufriesea Cockerell, and Exaerete Hoffmannsegg. Eulaema nigrita Lepeletier (41.6), Euglossa carolina Nemésio (15.3%), Eulaema marcii Nemésio (13.6%), and Euglossa melanotricha Moure (12.8%) were the most common species sampled. The distribution of collected specimens per fragment was as follows: Braúna (280 ha)--259 individuals belonging to 14 species; Cambuí (179 ha)--161 individuals from eight species; and Pindoba (100 ha)--207 individuals represented by seven species. Braúna had the highest diversity (H' = 1.91) and estimated species richness. The largest fragment was the main source of the observed variation in species richness and abundance, indicating a non-random pattern of spatial distribution. The analysis of environmental factors indicated that seasonal variation in these factors was the principal determinant of species occurrence and abundance.

  5. The hit problem for symmetric polynomials over the Steenrod algebra

    NASA Astrophysics Data System (ADS)

    Janfada, A. S.; Wood, R. M. W.

    2002-09-01

    We cite [18] for references to work on the hit problem for the polynomial algebra P(n) = [open face F]2[x1, ;…, xn] = [oplus B: plus sign in circle]d[gt-or-equal, slanted]0 Pd(n), viewed as a graded left module over the Steenrod algebra [script A] at the prime 2. The grading is by the homogeneous polynomials Pd(n) of degree d in the n> variables x1, …, xn of grading 1. The present article investigates the hit problem for the [script A]-submodule of symmetric polynomials B(n) = P(n)[sum L: summation operator]n , where [sum L: summation operator]n denotes the symmetric group on n> letters acting on the right of P(n). Among the main results is the symmetric version of the well-known Peterson conjecture. For a positive integer d, let [mu](d) denote the smallest value of k for which d = [sum L: summation operator]ki=1(2[lambda]i[minus sign]1), where [lambda]i [gt-or-equal, slanted] 0.

  6. Thin film mechanics

    NASA Astrophysics Data System (ADS)

    Cooper, Ryan C.

    This doctoral thesis details the methods of determining mechanical properties of two classes of novel thin films suspended two-dimensional crystals and electron beam irradiated microfilms of polydimethylsiloxane (PDMS). Thin films are used in a variety of surface coatings to alter the opto-electronic properties or increase the wear or corrosion resistance and are ideal for micro- and nanoelectromechanical system fabrication. One of the challenges in fabricating thin films is the introduction of strains which can arise due to application techniques, geometrical conformation, or other spurious conditions. Chapters 2-4 focus on two dimensional materials. This is the intrinsic limit of thin films-being constrained to one atomic or molecular unit of thickness. These materials have mechanical, electrical, and optical properties ideal for micro- and nanoelectromechanical systems with truly novel device functionality. As such, the breadth of applications that can benefit from a treatise on two dimensional film mechanics is reason enough for exploration. This study explores the anomylously high strength of two dimensional materials. Furthermore, this work also aims to bridge four main gaps in the understanding of material science: bridging the gap between ab initio calculations and finite element analysis, bridging the gap between ab initio calculations and experimental results, nanoscale to microscale, and microscale to mesoscale. A nonlinear elasticity model is used to determine the necessary elastic constants to define the strain-energy density function for finite strain. Then, ab initio calculations-density functional theory-is used to calculate the nonlinear elastic response. Chapter 2 focuses on validating this methodology with atomic force microscope nanoindentation on molybdenum disulfide. Chapter 3 explores the convergence criteria of three density functional theory solvers to further verify the numerical calculations. Chapter 4 then uses this model to investigate

  7. The fabrication of diversiform nanostructure forests based on residue nanomasks synthesized by oxygen plasma removal of photoresist

    NASA Astrophysics Data System (ADS)

    Mao, Haiyang; Wu, Di; Wu, Wengang; Xu, Jun; Hao, Yilong

    2009-11-01

    A simple lithography-free approach for fabricating diversiform nanostructure forests is presented. The key technique of the approach is that randomly distributed nanoscale residues can be synthesized on substrates simply by removing photoresist with oxygen plasma bombardment. These nanoresidues can function as masks in the subsequent etching process for nanopillars. By further spacer and then deep etching processes, a variety of forests composed of regular, tulip-like or hollow-head nanopillars as well as nanoneedles are successfully achieved in different etching conditions. The pillars have diameters of 30-200 nm and heights of 400 nm-3 µm. The needles reach several microns in height, with their tips less than 10 nm in diameter. Moreover, microstructures containing these nanostructure forests, such as surface microchannels, have also been fabricated. This approach is compatible with conventional micro/nano-electromechanical system (MEMS/NEMS) fabrication.

  8. Measuring and understanding radon adsorption in microporous materials

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Noel, Raymond, E-mail: noel@cppm.in2p3.fr; CINaM, Aix-Marseille Université, CNRS, Marseille; Busto, José, E-mail: busto@cppm.in2p3.fr

    The background from the radon decay chain is the strongest constraint for many experiments working at low energy and very low counting rate. A facility for studying the optimum radon capture by very selective porous materials was developed at CPPM in the context of the SuperNEM O project. In collaboration with Institut Jean Lamour, studies were carried out for better understanding radon adsorption in carbon adsorbents.

  9. Characterization and Performance Evaluation of an HPXe Detector for Nuclear Explosion Monitoring Applications

    DTIC Science & Technology

    2007-09-01

    performance of the detector, and to compare the performance with sodium iodide and germanium detectors. Monte Carlo ( MCNP ) simulation was used to...aluminum ~50% more efficient), and to estimate optimum shield dimensions for an HPXe based nuclear explosion monitor. MCNP modeling was also used to...detector were calculated with MCNP by using input activity levels as measured in routine NEM runs at Pacific Northwest National Laboratory (PNNL

  10. S-nitrosylation and S-glutathionylation of Cys134 on troponin I have opposing competitive actions on Ca2+ sensitivity in rat fast-twitch muscle fibers.

    PubMed

    Dutka, T L; Mollica, J P; Lamboley, C R; Weerakkody, V C; Greening, D W; Posterino, G S; Murphy, R M; Lamb, G D

    2017-03-01

    Nitric oxide is generated in skeletal muscle with activity and decreases Ca 2+ sensitivity of the contractile apparatus, putatively by S- nitrosylation of an unidentified protein. We investigated the mechanistic basis of this effect and its relationship to the oxidation-induced increase in Ca 2+ sensitivity in mammalian fast-twitch (FT) fibers mediated by S- glutathionylation of Cys134 on fast troponin I (TnI f ). Force-[Ca 2+ ] characteristics of the contractile apparatus in mechanically skinned fibers were assessed by direct activation with heavily Ca 2+ -buffered solutions. Treatment with S- nitrosylating agents, S- nitrosoglutathione (GSNO) or S- nitroso- N -acetyl-penicillamine (SNAP), decreased pCa 50 ( = -log 10 [Ca 2+ ] at half-maximal activation) by ~-0.07 pCa units in rat and human FT fibers without affecting maximum force, but had no effect on rat and human slow-twitch fibers or toad or chicken FT fibers, which all lack Cys134. The Ca 2+ sensitivity decrease was 1 ) fully reversed with dithiothreitol or reduced glutathione, 2 ) at least partially reversed with ascorbate, indicative of involvement of S-nitrosylation, and 3 ) irreversibly blocked by low concentration of the alkylating agent, N -ethylmaleimide (NEM). The biotin-switch assay showed that both GSNO and SNAP treatments caused S- nitrosylation of TnI f S- glutathionylation pretreatment blocked the effects of S- nitrosylation on Ca 2+ sensitivity, and vice-versa. S- nitrosylation pretreatment prevented NEM from irreversibly blocking S- glutathionylation of TnI f and its effects on Ca 2+ sensitivity, and likewise S- glutathionylation pretreatment prevented NEM block of S- nitrosylation. Following substitution of TnI f into rat slow-twitch fibers, S- nitrosylation treatment caused decreased Ca 2+ sensitivity. These findings demonstrate that S- nitrosylation and S- glutathionylation exert opposing effects on Ca 2+ sensitivity in mammalian FT muscle fibers, mediated by competitive actions on Cys134

  11. Effects of energy supplementation on energy losses and nitrogen balance of steers fed green-chopped wheat pasture I: Calorimetry.

    PubMed

    Shreck, A L; Ebert, P J; Bailey, E A; Jennings, J S; Casey, K D; Meyer, B E; Cole, N A

    2017-05-01

    Cattle grazing wheat pasture in the southern Great Plains are sometimes fed an energy supplement; however, the benefits of supplementation on nutrient balance, energy metabolism, and greenhouse gas emissions have not been elucidated. Therefore, we used 10 British crossbred steers (206 ± 10.7 kg initial BW) in a respiration calorimetry study to evaluate the effects of energy supplementation on energy losses, N balance, and nutrient digestibility of steers fed green-chopped wheat forage. The study design was an incomplete replicated 4 × 4 Latin square with treatments in a 2 × 2 factorial arrangement. Steers ( = 8) were assigned to 1 of 2 BW blocks (4 steers per block) with dietary factors consisting of 1) no supplementation (CON) or supplemented with a steam-flaked corn-based energy supplement (that also contained monensin sodium) at 0.5% of BW daily (SUP) and 2) NEm intakes of 1 times (1x) or 1.5 times (1.5x) maintenance. Wheat forage was harvested daily and continuously fed as green-chop to steers during the 56-d study. There were no differences ( ≥ 0.32) between CON and SUP for OM (78.3 vs. 80.7%, respectively) or NDF (68.3 vs. 64.8%, respectively) digestibility. At the 1.5x level of intake, there was no difference ( ≥ 0.16) in energy lost in feces (4.27 vs. 3.92 Mcal/d) or urine (0.58 vs. 0.55 Mcal/d), heat production (8.69 vs. 8.44 Mcal/d), or retained energy (3.10 vs. 3.46 Mcal/d) between supplementation treatments. Oxygen consumption (1,777 vs. 1,731 L/d; = 0.67) and CO production (1,704 vs. 1,627 L/d; = 0.56) of CON and SUP steers, respectively, were not different; however, SUP steers tended to have ( = 0.06) lower CH production (115 vs 130 L/d) than CON steers. Methane, as a proportion of GE intake, was similar for CON (6.87%) and SUP (6.07%; = 0.18), as was the ME:DE ratio ( = 0.24; 86.3% for CON and 87.9% for SUP). Fractional N excretion in urine and feces, as a proportion of total N excreted ( ≥ 0.84) or N intake ( ≥ 0.63), was not different

  12. Effects of Gold Salt Speciation and Structure of Human and Bovine Serum Albumins on the Synthesis and Stability of Gold Nanostructures

    PubMed Central

    Miranda, Érica G. A.; Tofanello, Aryane; Brito, Adrianne M. M.; Lopes, David M.; Albuquerque, Lindomar J. C.; de Castro, Carlos E.; Costa, Fanny N.; Giacomelli, Fernando C.; Ferreira, Fabio F.; Araújo-Chaves, Juliana C.; Nantes, Iseli L.

    2016-01-01

    The present study aimed to investigate the influence of albumin structure and gold speciation on the synthesis of gold nanoparticles (GNPs). The strategy of synthesis was the addition of HAuCl4 solutions at different pH values (3–12) to solutions of human and bovine serum albumins (HSA and BSA) at the same corresponding pH values. Different pH values influence the GNP synthesis due to gold speciation. Besides the inherent effect of pH on the native structure of albumins, the use N-ethylmaleimide (NEM)-treated and heat-denaturated forms of HSA and BSA provided additional insights about the influence of protein structure, net charge, and thiol group approachability on the GNP synthesis. NEM treatment, heating, and the extreme values of pH promoted loss of the native albumin structure. The formation of GNPs indicated by the appearance of surface plasmon resonance (SPR) bands became detectable from 15 days of the synthesis processes that were carried out with native, NEM-treated and heat-denaturated forms of HSA and BSA, exclusively at pH 6 and 7. After 2 months of incubation, SPR band was also detected for all synthesis carried out at pH 8.0. The mean values of the hydrodynamic radius (RH) were 24 and 34 nm for GNPs synthesized with native HSA and BSA, respectively. X-ray diffraction (XRD) revealed crystallites of 13 nm. RH, XRD, and zeta potential values were consistent with GNP capping by the albumins. However, the GNPs produced with NEM-treated and heat-denaturated albumins exhibited loss of protein capping by lowering the ionic strength. This result suggests a significant contribution of non-electrostatic interactions of albumins with the GNP surface, in these conditions. The denaturation of proteins exposes hydrophobic groups to the solvent, and these groups could interact with the gold surface. In these conditions, the thiol blockage or oxidation, the latter probably favored upon heating, impaired the formation of a stable capping by thiol coordination with

  13. Ultra-low power hydrogen sensing based on a palladium-coated nanomechanical beam resonator

    NASA Astrophysics Data System (ADS)

    Henriksson, Jonas; Villanueva, Luis Guillermo; Brugger, Juergen

    2012-07-01

    Hydrogen sensing is essential to ensure safety in near-future zero-emission fuel cell powered vehicles. Here, we present a novel hydrogen sensor based on the resonant frequency change of a nanoelectromechanical clamped-clamped beam. The beam is coated with a Pd layer, which expands in the presence of H2, therefore generating a stress build-up that causes the frequency of the device to drop. The devices are able to detect H2 concentrations below 0.5% within 1 s of the onset of the exposure using only a few hundreds of pW of power, matching the industry requirements for H2 safety sensors. In addition, we investigate the strongly detrimental effect that relative humidity (RH) has on the Pd responsivity to H2, showing that the response is almost nullified at about 70% RH. As a remedy for this intrinsic limitation, we applied a mild heating current through the beam, generating a few μW of power, whereby the responsivity of the sensors is fully restored and the chemo-mechanical process is accelerated, significantly decreasing response times. The sensors are fabricated using standard processes, facilitating their eventual mass-production.Hydrogen sensing is essential to ensure safety in near-future zero-emission fuel cell powered vehicles. Here, we present a novel hydrogen sensor based on the resonant frequency change of a nanoelectromechanical clamped-clamped beam. The beam is coated with a Pd layer, which expands in the presence of H2, therefore generating a stress build-up that causes the frequency of the device to drop. The devices are able to detect H2 concentrations below 0.5% within 1 s of the onset of the exposure using only a few hundreds of pW of power, matching the industry requirements for H2 safety sensors. In addition, we investigate the strongly detrimental effect that relative humidity (RH) has on the Pd responsivity to H2, showing that the response is almost nullified at about 70% RH. As a remedy for this intrinsic limitation, we applied a mild heating

  14. High surface area silicon materials: fundamentals and new technology.

    PubMed

    Buriak, Jillian M

    2006-01-15

    Crystalline silicon forms the basis of just about all computing technologies on the planet, in the form of microelectronics. An enormous amount of research infrastructure and knowledge has been developed over the past half-century to construct complex functional microelectronic structures in silicon. As a result, it is highly probable that silicon will remain central to computing and related technologies as a platform for integration of, for instance, molecular electronics, sensing elements and micro- and nanoelectromechanical systems. Porous nanocrystalline silicon is a fascinating variant of the same single crystal silicon wafers used to make computer chips. Its synthesis, a straightforward electrochemical, chemical or photochemical etch, is compatible with existing silicon-based fabrication techniques. Porous silicon literally adds an entirely new dimension to the realm of silicon-based technologies as it has a complex, three-dimensional architecture made up of silicon nanoparticles, nanowires, and channel structures. The intrinsic material is photoluminescent at room temperature in the visible region due to quantum confinement effects, and thus provides an optical element to electronic applications. Our group has been developing new organic surface reactions on porous and nanocrystalline silicon to tailor it for a myriad of applications, including molecular electronics and sensing. Integration of organic and biological molecules with porous silicon is critical to harness the properties of this material. The construction and use of complex, hierarchical molecular synthetic strategies on porous silicon will be described.

  15. Size-dependent Young’s modulus in ZnO nanowires with strong surface atomic bonds

    NASA Astrophysics Data System (ADS)

    Fan, Shiwen; Bi, Sheng; Li, Qikun; Guo, Qinglei; Liu, Junshan; Ouyang, Zhongliang; Jiang, Chengming; Song, Jinhui

    2018-03-01

    The mechanical properties of size-dependent nanowires are important in nano-electro-mechanical systems (NEMSs), and have attracted much research interest. Characterization of the size effect of nanowires in atmosphere directly to broaden their practical application instead of just in high vacuum situations, as reported previously, is desperately needed. In this study, we systematically studied the Young’s modulus of vertical ZnO nanowires in atmosphere. The diameters ranged from 48 nm to 239 nm with a resonance method using non-contact atomic force microscopy. The values of Young’s modulus in atmosphere present extremely strong increasing tendency with decreasing diameter of nanowire due to stronger surface atomic bonds compared with that in vacuum. A core-shell model for nanowires is proposed to explore the Young’s modulus enhancement in atmosphere, which is correlated with atoms of oxygen occurring near the nanowire surface. The modified model is more accurate for analyzing the mechanical behavior of nanowires in atmosphere compared with the model in vacuum. Furthermore, it is possible to use this characterization method to measure the size-related elastic properties of similar wire-sharp nanomaterials in atmosphere and estimate the corresponding mechanical behavior. The study of the size-dependent Young’s modulus in ZnO nanowires in atmosphere will improve the understanding of the mechanical properties of nanomaterials as well as providing guidance for applications in NEMSs, nanogenerators, biosensors and other related areas.

  16. First step to understand the importance of new deep aquifer pumping regime in groundwater system in a developing country, Kwale, Kenya.

    NASA Astrophysics Data System (ADS)

    Ferrer, Nuria; Folch, Albert; Lane, Mike; Thomas, Mike; Sasaka, Willie; Wara, Calvince; Banje, Said; Olago, Dan; Katuva, Jacob; Thomson, Patrick; Hope, Rob

    2016-04-01

    level and its quality either. So, in order to define the system and start to understand the different complex interactions, we present the initial results of the first complete water sampling field campaign (September 2015). Water isotope data and major ions were analyzed from 78 shallow and deep wells and surface water spread around study area. This field survey has been useful to understand the recharge, discharge areas and groundwater quality of deep aquifer system and which will have an important role for sustainable water management in the of Kwale area. Acknowledgements The research is primarily supported under the NERC/ESRC/DFID Unlocking the Potential of Groundwater for the Poor (UPGro) as a Catalyst Grant (NE/L001950/1) with work extending until 2019 as a Consortium Grant (NE/M008894/1), see http://www.upgro.org. Data for the paper will be publicly posted on the National Geoscience Data Centre and the UK Data Archive under the terms of the UPGro data management agreement.

  17. Abrasion properties of self-suspended hairy titanium dioxide nanomaterials

    NASA Astrophysics Data System (ADS)

    Zhang, Jiao-xia; Liu, Si; Yan, Chao; Wang, Xiao-jing; Wang, Lei; Yu, Ya-ming; Li, Shi-yun

    2017-11-01

    Considering the excellent solubility of pyrrolidone ring organic compounds, the synthesized N-(trimethoxysilyl) propyl- N-methyl-2-pyrrolidone chlorides was tethered onto titanium dioxide (TiO2) nanoparticles to improve dispersion of TiO2, and then polyethylene oxide (PEO) oligomer through ion exchange embraced the tethered TiO2 to obtain a novel self-suspended hairy TiO2 nanomaterials without any solvent. A variety of techniques were carried out to illustrate the structure and properties of the self-suspended hairy TiO2 nanomaterials. It was found that TiO2 nanoparticles embody monodispersity in the hybrid system though the "false reunion" phenomenon occurring due to nonpermanent weak physical cross-linking. Remarkably, self-suspended hairy TiO2 nanomaterials exhibit lower viscosity, facilitating maneuverable and outstanding antifriction and wear resistance properties, due to the synergistic lubricating effect between spontaneously forming lubricating film and nano-lubrication of TiO2 cores, overcoming the deficiency of both solid and liquid lubricants. This make them promising candidates for the micro-electromechanic/nano-electromechanic systems (MEMS/NEMS).

  18. Molecular dynamics simulation investigations of atomic-scale wear

    NASA Astrophysics Data System (ADS)

    Shao, Yuchong; Falk, Michael

    2013-03-01

    Frictional running-in and material transfer in wear take place at the micro- and nano-scale but the fundamental physics remain poorly understood. Here we intend to investigate wear and running-in phenomena in silicon based materials, which are widely utilized in micro/nano electromechanical systems(MEMS/NEMS). We use an atomic force microscopy (AFM) model composed of a crystalline silicon tip and substrate coated with native oxide layers. Molecular dynamics simulation has been performed over a range of temperatures, external loads and slip rates. Results show that adhesive wear takes place across the interface in an atom-by-atom fashion which remodels the tip leading to a final steady state. We quantify the rate of material transfer as a function of the coverage of non-bridging oxygen (NBO) atoms, which has a pronounced change of the system's tribological and wear behaviors. A constitutive rate and state model is proposed to predict the evolution of frictional strength and wear. This work is supported by the National Science Foundation under Award No. 0926111.

  19. Revisiting Yasinsky and Henry`s benchmark using modern nodal codes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Feltus, M.A.; Becker, M.W.

    1995-12-31

    The numerical experiments analyzed by Yasinsky and Henry are quite trivial by comparison with today`s standards because they used the finite difference code WIGLE for their benchmark. Also, this problem is a simple slab (one-dimensional) case with no feedback mechanisms. This research attempts to obtain STAR (Ref. 2) and NEM (Ref. 3) code results in order to produce a more modern kinetics benchmark with results comparable WIGLE.

  20. Atomistic Design and Simulations of Nanoscale Machines and Assembly

    NASA Technical Reports Server (NTRS)

    Goddard, William A., III; Cagin, Tahir; Walch, Stephen P.

    2000-01-01

    Over the three years of this project, we made significant progress on critical theoretical and computational issues in nanoscale science and technology, particularly in:(1) Fullerenes and nanotubes, (2) Characterization of surfaces of diamond and silicon for NEMS applications, (3) Nanoscale machine and assemblies, (4) Organic nanostructures and dendrimers, (5) Nanoscale confinement and nanotribology, (6) Dynamic response of nanoscale structures nanowires (metals, tubes, fullerenes), (7) Thermal transport in nanostructures.

  1. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bertholon, François; Harant, Olivier; Bourlon, Bertrand

    This article introduces a joined Bayesian estimation of gas samples issued from a gas chromatography column (GC) coupled with a NEMS sensor based on Giddings Eyring microscopic molecular stochastic model. The posterior distribution is sampled using a Monte Carlo Markov Chain and Gibbs sampling. Parameters are estimated using the posterior mean. This estimation scheme is finally applied on simulated and real datasets using this molecular stochastic forward model.

  2. Post-Fusion Membrane Reorganization.

    DTIC Science & Technology

    1993-01-27

    diphosphoglycerate , and NEM (a crosslinking agent), and ethanol treatments all had reproducible and very specific effects on the kinetic phases and the fusion product...actually, at the ultrastructure level , a double membrane multiply perforated with fusion sites (or pores). Also, because the heat treatment was within...relationships. Moreover. 2.3- Diphosphoglycerate (2-3-DPG). a naturally occuring metabolite which is known to have a regulatory role in spectrin-cytoskeletal

  3. Equipment management user's handbook for property custodians

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The NASA Equipment Management User's Handbook for Property Custodians is issued as an instructional guide for personnel designated as property custodians and technical personnel involved in the acquisition, management, and use of NASA-owned equipment. This handbook provides general information and basic operational procedures for processing equipment transactions through the agency-wide NASA Equipment Management System (NEMS). Each NASA installation must prepare supplementary instructions for local requirements beyond the scope of NASA-wide policies and procedures contained herein, or as specified for local implementation in NHB 4200.1, 'NASA Equipment Management Manual.' NHB 4200.1 sets forth policy, uniform performance standards, and procedural guidance to NASA personnel for the acquisition, management, and use of NASA-owned equipment. This handbook is a controlled document, issued in loose-leaf form and revised by page changes. Additional copies for internal use may be obtained through normal distribution.

  4. Nutrition environments in corner stores in Philadelphia.

    PubMed

    Cavanaugh, Erica; Mallya, Giridhar; Brensinger, Colleen; Tierney, Ann; Glanz, Karen

    2013-02-01

    To examine the availability, quality, and price of key types of healthy and less-healthy foods found in corner stores in low-income urban neighborhoods and the associations between store characteristics and store food environments. A sample of 246 corner stores was selected from all corner stores participating in the Philadelphia Healthy Corner Store Initiative (HCSI). The Nutrition Environment Measures Survey for Corner Stores (NEMS-CS) was used to assess the availability, quality, and price of foods and beverages in 11 common categories between February and May, 2011. NEMS-CS measures were completed in 233 stores, 94.7% of the 246 stores approached. The healthier options were significantly less available in all food categories and often more expensive. Baked goods, bread, chips and cereals were sold at nearly all stores, with significantly fewer offering low-fat baked goods (5.7%, p<0.0001), whole grain bread (56.2%, p<0.0001), or baked chips (35.2%, p<0.0001). Number of aisles was positively associated with availability score (p<0.05). Findings from this study point toward potential targets for intervention to improve the corner store food environment and dietary choices among low-income urban populations. Availability of certain healthier foods could be improved. Copyright © 2012 Elsevier Inc. All rights reserved.

  5. Investigation variation of carbon dioxide based on GOSAT data in peninsular Malaysia

    NASA Astrophysics Data System (ADS)

    Sim, C. K.; Lim, H. S.; MatJafri, M. Z.

    2015-10-01

    Carbon dioxide (CO2) is an inodorous and transparent gas, and naturally originates in our atmosphere. Due to its optical characteristics, CO2 is the most important greenhouse gas and play a key role in climate change due to an effective thermal infrared (IR) radiation absorber. Satellite observations of atmospheric carbon dioxide (CO2) can significantly improve our knowledge about the sources and sinks of CO2. The remote sensing satellite, namely Greenhouse Gases Observing Satellite (GOSAT) was employed to investigate the spatial and variations of CO2 column-averaged dry airmole fractions, denoted XCO2 over Peninsular Malaysia from January 2013 to December 2013. The analysis of CO2 in the study area shows the significant differences between northeast monsoon (NEM) and the southwest monsoon (SWM). During NEM season, cold air outbreaks from Siberia spreads to equatorial region in the form of north-easterly cold surge winds and associated with a low-level anticyclone over Southeast Asia. Inversely, air masses from the southwest contribute to long-range air pollution due to transportation of atmospheric CO2 by wind is associated with biomass burning in Sumatra, Indonesia. The GOSAT data and the Satellite measurements are able to measure the increase of the atmosphere CO2 values over different regions.

  6. Changes in food and beverage environments after an urban corner store intervention.

    PubMed

    Cavanaugh, Erica; Green, Sarah; Mallya, Giridhar; Tierney, Ann; Brensinger, Colleen; Glanz, Karen

    2014-08-01

    In response to the obesity epidemic, interventions to improve the food environment in corner stores have gained attention. This study evaluated the availability, quality, and price of foods in Philadelphia corner stores before and after a healthy corner store intervention with two levels of intervention intensity ("basic" and "conversion"). Observational measures of the food environment were completed in 2011 and again in 2012 in corner stores participating in the intervention, using the Nutrition Environment Measures Survey for Corner Stores (NEMS-CS). Main analyses included the 211 stores evaluated at both time-points. A time-by-treatment interaction analysis was used to evaluate the changes in NEMS-CS scores by intervention level over time. Availability of fresh fruit increased significantly in conversion stores over time. Specifically, there were significant increases in the availability of apples, oranges, grapes, and broccoli in conversion stores over time. Conversion stores showed a trend toward a significantly larger increase in the availability score compared to basic stores over time. Interventions aimed at increasing healthy food availability are associated with improvements in the availability of low-fat milk, fruits, and some vegetables, especially when infrastructure changes, such as refrigeration and shelving enhancements, are offered. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Hyptis suaveolens (L.) Poit (Lamiaceae), a medicinal plant protects the stomach against several gastric ulcer models.

    PubMed

    Jesus, N Z T; Falcão, H S; Lima, G R M; Caldas Filho, M R D; Sales, I R P; Gomes, I F; Santos, S G; Tavares, J F; Barbosa-Filho, J M; Batista, L M

    2013-12-12

    Hyptis suaveolens is used by the traditional population in several parts of the world to treat inflammation, gastric ulcer and infection and is used as a crude drug to relieve symptoms related with gastric ulcer or gastritis in northeaster and central region of Brazil. the standardized ethanolic extract (Hs-EtOHE) and hexanic fraction (Hs-HexF) of Hyptis suaveolens (62,5, 125, 250 and 500 mg/kg) was evaluated in several models of acute gastric ulcers. The participation of NO was evaluated by pretreatment with L-NAME and non-protein sulfyhydryls by NEM in the gastroprotective effect. Hs-EtOHE and Hs-HexF markedly reduced the gastric lesions induced by all ulcerogenic agents (HCl/ethanol, ethanol, NSAIDs and hypothermic restraint-stress). Gastric ulcerations were exacerbated by administration of NEM suggesting that the gastroprotective mechanism of action of Hs-EtOHE and Hs-HexF involves sulfhydryl groups. Ours results show that an extract of Hyptis suaveolens, administered orally to rodents, present gastro protective activity in different models of acute of gastric ulcer and give some support to the reported claims on the use of this plant as a gastro protective agent. © 2013 Published by Elsevier Ireland Ltd.

  8. Modeling and analysis of a resonant nanosystem

    NASA Astrophysics Data System (ADS)

    Calvert, Scott L.

    The majority of investigations into nanoelectromechanical resonators focus on a single area of the resonator's function. This focus varies from the development of a model for a beam's vibration, to the modeling of electrostatic forces, to a qualitative explanation of experimentally-obtained currents. Despite these efforts, there remains a gap between these works, and the level of sophistication needed to truly design nanoresonant systems for efficient commercial use. Towards this end, a comprehensive system model for both a nanobeam resonator and its related experimental setup is proposed. Furthermore, a simulation arrangement is suggested as a method for facilitating the study of the system-level behavior of these devices in a variety of cases that could not be easily obtained experimentally or analytically. The dynamics driving the nanoresonator's motion, as well as the electrical interactions influencing the forcing and output of the system, are modeled, experimentally validated, and studied. The model seeks to develop both a simple circuit representation of the nanoresonator, and to create a mathematical system that can be used to predict and interpret the observed behavior. Due to the assumptions used to simplify the model to a point of reasonable comprehension, the model is most accurate for small beam deflections near the first eigenmode of the beam. The process and results of an experimental investigation are documented, and compared with a circuit simulation modeling the full test system. The comparison qualitatively proves the functionality of the model, while a numerical analysis serves to validate the functionality and setup of the circuit simulation. The use of the simulation enables a much broader investigation of both the electrical behavior and the physical device's dynamics. It is used to complement an assessment of the tuning behavior of the system's linear natural frequency by demonstrating the tuning behavior of the full nonlinear response. The

  9. Valence Band Control of Metal Silicide Films via Stoichiometry.

    PubMed

    Streller, Frank; Qi, Yubo; Yang, Jing; Mangolini, Filippo; Rappe, Andrew M; Carpick, Robert W

    2016-07-07

    The unique electronic and mechanical properties of metal silicide films render them interesting for advanced materials in plasmonic devices, batteries, field-emitters, thermoelectric devices, transistors, and nanoelectromechanical switches. However, enabling their use requires precisely controlling their electronic structure. Using platinum silicide (PtxSi) as a model silicide, we demonstrate that the electronic structure of PtxSi thin films (1 ≤ x ≤ 3) can be tuned between metallic and semimetallic by changing the stoichiometry. Increasing the silicon content in PtxSi decreases the carrier density according to valence band X-ray photoelectron spectroscopy and theoretical density of states (DOS) calculations. Among all PtxSi phases, Pt3Si offers the highest DOS due to the modest shift of the Pt5d manifold away from the Fermi edge by only 0.5 eV compared to Pt, rendering it promising for applications. These results, demonstrating tunability of the electronic structure of thin metal silicide films, suggest that metal silicides can be designed to achieve application-specific electronic properties.

  10. Slippage and boundary layer probed in an almost ideal gas by a nanomechanical oscillator.

    PubMed

    Defoort, M; Lulla, K J; Crozes, T; Maillet, O; Bourgeois, O; Collin, E

    2014-09-26

    We measure the interaction between ⁴He gas at 4.2 K and a high-quality nanoelectromechanical string device for its first three symmetric modes (resonating at 2.2, 6.7, and 11 MHz with quality factor Q>0.1×10⁶) over almost 6 orders of magnitude in pressure. This fluid can be viewed as the best experimental implementation of an almost ideal monoatomic and inert gas of which properties are tabulated. The experiment ranges from high pressure where the flow is of laminar Stokes-type presenting slippage down to very low pressures where the flow is molecular. In the molecular regime, when the mean-free path is of the order of the distance between the suspended nanomechanical probe and the bottom of the trench, we resolve for the first time the signature of the boundary (Knudsen) layer onto the measured dissipation. Our results are discussed in the framework of the most recent theories investigating boundary effects in fluids (both analytic approaches and direct simulation Monte Carlo methods).

  11. Self-excitation of single nanomechanical pillars

    NASA Astrophysics Data System (ADS)

    Kim, Hyun S.; Qin, Hua; Blick, Robert H.

    2010-03-01

    Self-excitation is a mechanism that is ubiquitous for electromechanical power devices such as electrical generators. This is conventionally achieved by making use of the magnetic field component in electrical generators (Nedic and Lipo 2000 IEEE/IAS Conf. Records (Rome, Italy) vol 1 pp 51-6), a good and widely visible example of which is the wind turbine farm (Muljadi et al 2005 J. Sol. Energy Eng. 127 581-7). In other words, a static force, such as the wind acting on rotor blades, can generate a resonant excitation at a certain mechanical frequency. For nanomechanical systems (Craighead 2000 Science 290 1532-5 Roukes 2001 Phys. World 14 25-31 Cleland 2003 Foundations of Nanomechanics (Berlin: Springer); Ayari et al 2007 Nano Lett. 7 2252-7 Koenig et al 2008 Nat. Nanotechnol. 3 482-4) such a self-excitation (SE) mechanism is also highly desirable, because it can generate mechanical oscillations at radio frequencies by simply applying a dc bias voltage. This is of great importance for low-power signal communication devices and detectors, as well as for mechanical computing elements. For a particular nanomechanical system—the single electron shuttle—this effect was predicted some time ago by Gorelik et al (Phys. Rev. Lett. 80 4526-9). Here, we use a nanoelectromechanical single electron transistor (NEMSET) to demonstrate self-excitation for both the soft and hard regimes, respectively. The ability to use self-excitation in nanomechanical systems may enable the detection of quantum mechanical backaction effects (Naik et al 2006 Nature 443 193-6) in direct tunneling, macroscopic quantum tunneling (Savelev et al 2006 New J. Phys. 8 105-15) and rectification (Pistolesi and Fazio 2005 Phys. Rev. Lett. 94 036806-4). All these effects have so far been overshadowed by the large driving voltages that had to be applied.

  12. Direct observation of single-charge-detection capability of nanowire field-effect transistors.

    PubMed

    Salfi, J; Savelyev, I G; Blumin, M; Nair, S V; Ruda, H E

    2010-10-01

    A single localized charge can quench the luminescence of a semiconductor nanowire, but relatively little is known about the effect of single charges on the conductance of the nanowire. In one-dimensional nanostructures embedded in a material with a low dielectric permittivity, the Coulomb interaction and excitonic binding energy are much larger than the corresponding values when embedded in a material with the same dielectric permittivity. The stronger Coulomb interaction is also predicted to limit the carrier mobility in nanowires. Here, we experimentally isolate and study the effect of individual localized electrons on carrier transport in InAs nanowire field-effect transistors, and extract the equivalent charge sensitivity. In the low carrier density regime, the electrostatic potential produced by one electron can create an insulating weak link in an otherwise conducting nanowire field-effect transistor, modulating its conductance by as much as 4,200% at 31 K. The equivalent charge sensitivity, 4 × 10(-5) e Hz(-1/2) at 25 K and 6 × 10(-5) e Hz(-1/2) at 198 K, is orders of magnitude better than conventional field-effect transistors and nanoelectromechanical systems, and is just a factor of 20-30 away from the record sensitivity for state-of-the-art single-electron transistors operating below 4 K (ref. 8). This work demonstrates the feasibility of nanowire-based single-electron memories and illustrates a physical process of potential relevance for high performance chemical sensors. The charge-state-detection capability we demonstrate also makes the nanowire field-effect transistor a promising host system for impurities (which may be introduced intentionally or unintentionally) with potentially long spin lifetimes, because such transistors offer more sensitive spin-to-charge conversion readout than schemes based on conventional field-effect transistors.

  13. Movement of gating machinery during the activation of rod cyclic nucleotide-gated channels.

    PubMed Central

    Brown, R L; Snow, S D; Haley, T L

    1998-01-01

    In the visual and olfactory systems, cyclic nucleotide-gated (CNG) ion channels convert stimulus-induced changes in the internal concentrations of cGMP and cAMP into changes in membrane potential. Although it is known that significant activation of these channels requires the binding of three or more molecules of ligand, the detailed molecular mechanism remains obscure. We have probed the structural changes that occur during channel activation by using sulfhydryl-reactive methanethiosulfonate (MTS) reagents and N-ethylmaleimide (NEM). When expressed in Xenopus oocytes, the alpha-subunit of the bovine retinal channel forms homomultimeric channels that are activated by cGMP with a K1/2 of approximately 100 microM. Cyclic AMP, on the other hand, is a very poor activator; a saturating concentration elicits only 1% of the maximum current produced by cGMP. Treatment of excised patches with MTS-ethyltrimethylamine (MTSET) or NEM dramatically potentiated the channel's response to both cyclic nucleotides. After MTSET treatment, the dose-response relation for cGMP was shifted by over two orders of magnitude to lower concentrations. The effect on channel activation by cAMP was even more striking. After modification, the channels were fully activated by cAMP with a K1/2 of approximately 60 microM. This potentiation was abolished by conversion of Cys481 to a nonreactive alanine residue. Potentiation occurred more rapidly in the presence of saturating cGMP, indicating that this region of the channel is more accessible when the channel is open. Cys481 is located in a linker region between the transmembrane and cGMP-binding domains of the channel. These results suggest that this region of the channel undergoes significant movement during the activation process and is critical for coupling ligand binding to pore opening. Potentiation, however, is not mediated by the recently reported interaction between the amino- and carboxy-terminal regions of the alpha-subunit. Deletion of the

  14. Meteorological controls on isotope ratios in rainwater from an inland and a costal station (Bangalore and Thiruvananthapuram) in Southern India

    NASA Astrophysics Data System (ADS)

    Peethambaran, Rahul; Ghosh, Prosenjit

    2017-04-01

    The isotope ratios in rainwater are controlled by factors such as source water composition and intensity of convective activity (Rahul et al., 2016). In this study, we investigate the atmospheric controls on rainwater δ18O values collected from two Indian stations, Thiruvananthapuram (TRV, n=222 with average of -2.58±3.06‰) and Bangalore (BLR, n=198 with average of -1.94±3.94‰) covering the southwest monsoon (SWM) and northeast monsoon (NEM), for the time period of four years. The samples are collected at daily intervals and in some particular cases at intra-event time scales (4 events). It was observed that the seasonal variations are more pronounced over BLR due to its location in the central peninsular India, compared to TRV which is a coastal station. The intra-event based observations indicate amount effect is significant due to post-condensation evaporation during raindrop descent. This is supported by the observed low d-excess values of rainwater and its inverse correlation (r=0.5 to 0.8) with rainfall amount within events. The correlation between rainwater δ18O with the local rainfall amount was low (r=0.2 and 0.3) in both the stations whereas the isotope ratios respond to the monsoonal convective systems on a regional scale. Significant negative correlations of isotope ratios with the moisture convergence were obtained in spatio-temporal scales over parts of the Arabian Sea as well as over the regions of moisture pathways associated with synoptic scale disturbances over the BoB. We observe that the correlation pattern responds to seasonal changes at the moisture source regions during the period of SWM and NEM. References Rahul, P., P. Ghosh, S. K. Bhattacharya, and K. Yoshimura (2016), Controlling factors of rainwater and water vapor isotopes at Bangalore, India: constraints from observations in 2013 Indian monsoon, J. Geophys. Res. Atmos., 121, doi:10.1002/2016JD025352.

  15. Tri-FAST Hardware-in-the-Loop Simulation. Volume I. Tri-FAST Hardware-in-the-Loop Simulation at the Advanced Simulation Center

    DTIC Science & Technology

    1979-03-28

    TECHNICAL REPORT T-79-43 TRI- FAST HARDWARE-IN-THE-LOOP SIMULATION Volume 1: Trn FAST Hardware-In-the. Loop Simulation at the Advanced Simulation...Identify by block number) Tri- FAST Hardware-in-the-Loop ACSL Advanced Simulation Center Simulation RF Target Models I a. AfIACT ( sin -oveme skit N nem...e n tdositr by block number) The purpose of this report is to document the Tri- FAST missile simulation development and the seeker hardware-in-the

  16. Adaptation and Validation of a Nutrition Environment Measures Survey for University Grab-and-Go Establishments.

    PubMed

    Lo, Brian K C; Minaker, Leia; Chan, Alicia N T; Hrgetic, Jessica; Mah, Catherine L

    2016-03-01

    To adapt and validate a survey instrument to assess the nutrition environment of grab-and-go establishments at a university campus. A version of the Nutrition Environment Measures Survey for grab-and-go establishments (NEMS-GG) was adapted from existing NEMS instruments and tested for reliability and validity through a cross-sectional assessment of the grab-and-go establishments at the University of Toronto. Product availability, price, and presence of nutrition information were evaluated. Cohen's kappa coefficient and intra-class correlation coefficients (ICC) were assessed for inter-rater reliability, and construct validity was assessed using the known-groups comparison method (via store scores). Fifteen grab-and-go establishments were assessed. Inter-rater reliability was high with an almost perfect agreement for availability (mean κ = 0.995) and store scores (ICC = 0.999). The tool demonstrated good face and construct validity. About half of the venues carried fruit and vegetables (46.7% and 53.3%, respectively). Regular and healthier entrée items were generally the same price. Healthier grains were cheaper than regular options. Six establishments displayed nutrition information. Establishments operated by the university's Food Services consistently scored the highest across all food premise types for nutrition signage, availability, and cost of healthier options. Health promotion strategies are needed to address availability and variety of healthier grab-and-go options in university settings.

  17. Identification of a Nfs1p-bound persulfide intermediate in Fe-S cluster synthesis by intact mitochondria.

    PubMed

    Pandey, Alok; Yoon, Heeyong; Lyver, Elise R; Dancis, Andrew; Pain, Debkumar

    2012-09-01

    Cysteine desulfurases generate a covalent persulfide intermediate from cysteine, and this activated form of sulfur is essential for the synthesis of iron-sulfur (Fe-S) clusters. In yeast mitochondria, there is a complete machinery for Fe-S cluster synthesis, including a cysteine desulfurase, Nfs1p. Here we show that following supplementation of isolated mitochondria with [(35)S]cysteine, a radiolabeled persulfide could be detected on Nfs1p. The persulfide persisted under conditions that did not permit Fe-S cluster formation, such as nucleotide and/or iron depletion of mitochondria. By contrast, under permissive conditions, the radiolabeled Nfs1p persulfide was greatly reduced and radiolabeled aconitase was formed, indicating transfer of persulfide to downstream Fe-S cluster recipients. Nfs1p in mitochondria was found to be relatively more resistant to inactivation by N-ethylmaleimide (NEM) as compared with a prokaryotic cysteine desulfurase. Mitochondria treated with NEM (1 mM) formed the persulfide on Nfs1p but failed to generate Fe-S clusters on aconitase, likely due to inactivation of downstream recipient(s) of the Nfs1p persulfide. Thus the Nfs1p-bound persulfide as described here represents a precursor en route to Fe-S cluster synthesis in mitochondria. Copyright © 2012 Elsevier B.V. and Mitochondria Research Society. All rights reserved.

  18. Review of Nimbus-5 Microwave Spectrometer results. [atmospheric temperature profile measurement

    NASA Technical Reports Server (NTRS)

    Staelin, D. H.

    1974-01-01

    Nimbus-E Microwave Spectrometer (NEMS) data are analyzed, especially those obtained from the 53.65, 54.9, and 58.8 GHz channels, corresponding to sensing at 4, 11, and 18 km respectively. The observations permit highly precise horizontal temperature profiles to be established and are hardly affected by clouds. The sensings of the 54.9 GHz channel unambiguously delineate wave structure on the equator. Horizontal water vapor profiles are derived from the 22.235 and 31.4 GHz channel data.

  19. Technology Insertion Engineering Services Process Characterization Task Order No. 1. Database Documentation Book for OO-ALC MANPNA

    DTIC Science & Technology

    1989-12-15

    WAS GCf& NemA -co q, L.AjE-WAs Si-ur L)OLAi . I (Satw PACE ’o r-O SCUSs/AJ OuJ T’,s Ih6 PJ-7T~j OP~rZ4TIOAJ 7 N-E7V OAXY 12A~J OA Z-I AJO- C T As...F11111111 - -- - --------- .. ,,,,,,,, , -m -- - -- -CI In NNNO 3NI - - -~NOW ON, NORM - ~ I .uuANN I a a ON m.,-- I -- - -- - - -- - - - IF 7W- a Liflo L- !i

  20. Dissolved nutrient balance and net ecosystem metabolism in a Mediterranean-climate coastal lagoon: San Diego Bay

    NASA Astrophysics Data System (ADS)

    Delgadillo-Hinojosa, F.; Zirino, A.; Holm-Hansen, O.; Hernández-Ayón, J. M.; Boyd, T. J.; Chadwick, B.; Rivera-Duarte, I.

    2008-02-01

    The temporal and spatial variability of dissolved inorganic phosphate (DIP), nitrogen (DIN), carbon (DIC) and dissolved organic carbon (DOC) were studied in order to determine the net ecosystem metabolism (NEM) of San Diego Bay (SDB), a Mediterranean-climate lagoon. A series of four sampling campaigns were carried out during the rainy (January 2000) and the dry (August 2000 and May and September 2001) seasons. During the dry season, temperature, salinity and DIP, DIC and DOC concentrations increased from oceanic values in the outer bay to higher values at the innermost end of the bay. DIP, DIC and DOC concentrations showed a clear offset from conservative mixing implying production of these dissolved materials inside the bay. During the rainy season, DIP and DOC increased to the head, whereas salinity decreased toward the mouth due to land runoff and river discharges. The distributions of DIP and DOC also showed a deviation from conservative mixing in this season, implying a net addition of these dissolved materials during estuarine mixing within the bay. Mass balance calculations showed that SDB consistently exported DIP (2.8-9.8 × 10 3 mol P d -1), DIC (263-352 × 10 3 mol C d -1) and DOC (198-1233 × 10 3 mol C d -1), whereas DIN (5.5-18.2 × 10 3 mol N d -1) was exported in all samplings except in May 2001 when it was imported (8.6 × 10 3 mol N d -1). The DIP, DIC and DOC export rates along with the strong relationship between DIP, DIC or DOC and salinity suggest that intense tidal mixing plays an important role in controlling their distributions and that SDB is a source of nutrients and DOC to the Southern California Bight. Furthermore, NEM ranged from -8.1 ± 1.8 mmol C m -2 d -1 in September to -13.5 ± 5.8 mmol C m -2 d -1 in January, highlighting the heterotrophic character of SDB. In order to explain the net heterotrophy of this system, we postulate that phytoplankton-derived particulate organic matter, stimulated by upwelling processes in the adjacent