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Sample records for suspended nanobelt bimorph

  1. Ac dielectrophoresis of tin oxide nanobelts suspended in ethanol: manipulation and visualization.

    PubMed

    Kumar, Surajit; Peng, Zhengchun; Shin, Heungjoo; Wang, Zhong Lin; Hesketh, Peter J

    2010-03-15

    This article presents results of detailed and direct real-time observations of the wide variety of SnO(2) nanobelt motions induced by ac dielectrophoresis (DEP) in an innovative microfluidic setup. High ac electric fields were generated on a gold microelectrode (approximately 20 microm electrode gap) array, patterned on a glass substrate and covered by a approximately 10 microm tall polydimethylsiloxane (PDMS) microchannel. Ethanol suspended SnO(2) nanobelts were introduced into the microchannel, and the DEP experiments were performed. Negative DEP (repulsion) of the nanobelts was observed in the low-frequency range (<100 kHz) of the applied electric field, which caused rigid body motion as well as deformation of the nanobelts. The negative DEP effect observed in ethanol is unusual and contrary to what is predicted by the Clausius-Mossotti factor (using bulk SnO(2) conductivity and permittivity values) of the dipole approximation theory. In the high-frequency range (approximately 1-10 MHz), positive DEP (attraction) of the nanobelts was observed. Pearl chain formation involving short nanobelts and particles was also observed in the two DEP regimes. PMID:20151680

  2. Fluidic and dielectrophoretic manipulation of tin oxide nanobelts

    NASA Astrophysics Data System (ADS)

    Kumar, Surajit

    Nanobelts are a new class of semiconducting metal oxide nanowires with great potential for nanoscale devices. The present research focuses on the manipulation of SnO2 nanobelts suspended in ethanol using microfluidics and electric fields. Dielectrophoresis (DEP) was demonstrated for the first time on semiconducting metal oxide nanobelts, which also resulted in the fabrication of a multiple nanobelt device. Detailed and direct real-time observations of the wide variety of nanobelt motions induced by DEP forces were conducted using an innovative setup and an inverted optical microscope. High AC electric fields were generated on a gold microelectrode (˜20 mum gap) array, patterned on glass substrate, and covered by a ˜10 mum tall PDMS (polydimethylsiloxane) channel, into which the nanobelt suspension was introduced for performing the DEP experiments. Negative DEP (repulsion) of the nanobelts was observed in the low frequency range (<100 kHz) of the applied voltage, which caused rigid body motion as well as deformation of the nanobelts. In the high frequency range (˜1 MHz--10 MHz), positive DEP (attraction) of the nanobelts was observed. Using a parallel plate electrode arrangement, evidence of electrophoresis was also found for DC and low frequency (Hz) voltages. The existence of negative DEP effect is unusual considering the fact that if bulk SnO2 conductivity and permittivity values are used in combination with ethanol properties to calculate the Clausius Mossotti factor using the simple dipole approximation theory; it predicts positive DEP for most of the frequency range experimentally studied. A fluidic nanobelt alignment technique was studied and used in the fabrication of single nanobelt devices with small electrode gaps. These devices were primarily used for conducting impedance spectroscopy measurements to obtain an estimate of the nanobelt electrical conductivity. Parametric numerical studies were conducted using COMSOL Multiphysics software package to

  3. Bimorphic polymeric photomechanical actuator

    NASA Technical Reports Server (NTRS)

    Sarkisov, Sergey S. (Inventor); Curley, Michael J. (Inventor); Adamovsky, Grigory (Inventor); Sarkisov, Jr., Sergey S. (Inventor); Fields, Aisha B. (Inventor)

    2006-01-01

    A bimorphic polymeric photomechanical actuator, in one embodiment using polyvinylidene fluoride (PVDF) as a photosensitive body, transmitting light over fiber optic cables, and controlling the shape and pulse duration of the light pulse to control movement of the actuator. Multiple light beams are utilized to generate different ranges of motion for the actuator from a single photomechanical body and alternative designs use multiple light beams and multiple photomechanical bodies to provide controlled movement. Actuator movement using one or more ranges of motion is utilized to control motion to position an actuating element in three dimensional space.

  4. Note: Helical nanobelt force sensors

    SciTech Connect

    Hwang, G.; Hashimoto, H.

    2012-12-15

    We present the fabrication and characterization of helical nanobelt force sensors. These self-sensing force sensors are based on the giant piezoresistivity of helical nanobelts. The three-dimensional helical nanobelts are self-formed from 27 nm-thick n-type InGaAs/GaAs bilayers using rolled-up techniques, and assembled onto electrodes on a micropipette using nanorobotic manipulations. The helical nanobelt force sensors can be calibrated using a calibrated atomic force microscope cantilever system under scanning electron microscope. Thanks to their giant piezoresistance coefficient (515 Multiplication-Sign 10{sup -10} Pa{sup -1}), low stiffness (0.03125 N/m), large-displacement capability ({approx}10 {mu}m), and good fatigue resistance, they are well suited to function as stand-alone, compact ({approx}20 {mu}m without the plug-in support), light ({approx}5 g including the plug-in support), versatile and large range ({approx}{mu}N) and high resolution ({approx}nN) force sensors.

  5. Light-Driven Polymeric Bimorph Actuators

    NASA Technical Reports Server (NTRS)

    Adamovsky, Gregory; Sarkisov, Sergey S.; Curley, Michael J.

    2009-01-01

    Light-driven polymeric bimorph actuators are being developed as alternatives to prior electrically and optically driven actuators in advanced, highly miniaturized devices and systems exemplified by microelectromechanical systems (MEMS), micro-electro-optical-mechanical systems (MEOMS), and sensor and actuator arrays in smart structures. These light-driven polymeric bimorph actuators are intended to satisfy a need for actuators that (1) in comparison with the prior actuators, are simpler and less power-hungry; (2) can be driven by low-power visible or mid-infrared light delivered through conventional optic fibers; and (3) are suitable for integration with optical sensors and multiple actuators of the same or different type. The immediate predecessors of the present light-driven polymeric bimorph actuators are bimorph actuators that exploit a photorestrictive effect in lead lanthanum zirconate titanate (PLZT) ceramics. The disadvantages of the PLZT-based actuators are that (1) it is difficult to shape the PLZT ceramics, which are hard and brittle; (2) for actuation, it is necessary to use ultraviolet light (wavelengths < 380 nm), which must be generated by use of high-power, high-pressure arc lamps or lasers; (3) it is difficult to deliver sufficient ultraviolet light through conventional optical fibers because of significant losses in the fibers; (4) the response times of the PLZT actuators are of the order of several seconds unacceptably long for typical applications; and (5) the maximum mechanical displacements of the PLZT-based actuators are limited to those characterized by low strains beyond which PLZT ceramics disintegrate because of their brittleness. The basic element of a light-driven bimorph actuator of the present developmental type is a cantilever beam comprising two layers, at least one of which is a polymer that exhibits a photomechanical effect (see figure). The dominant mechanism of the photomechanical effect is a photothermal one: absorption of

  6. Dual-use bimorph deformable mirrors

    NASA Astrophysics Data System (ADS)

    Griffith, M. S.; Laycock, L. C.; Bagshaw, J. M.; Rowe, D.

    2005-11-01

    Adaptive Optics (AO) is a critical underpinning technology for future optical countermeasures, laser delivery, target illumination and imaging systems. It measures and compensates for optical distortion caused by transmission through the atmosphere, resulting in the ability to deploy smaller lasers and identify targets at greater ranges. AO is also well established in ground based astronomy, and is finding applications in free space optical communications and ophthalmology. One of the key components in an AO system is the wavefront modifier, which acts on the incoming or outgoing beam to counter the effects of the atmosphere. BAE SYSTEMS ATC is developing multi-element Deformable Bimorph Mirrors (DBMs) for such applications. A traditional bimorph deformable mirror uses a set of edge electrodes outside the active area in order to meet the required boundary conditions for the active aperture. This inflicts a significant penalty in terms of bandwidth, which is inversely proportional to the square of the full mirror diameter. We have devised a number of novel mounting arrangements that reduce dead space and thus provide a much improved trade-off between bandwidth and stroke. These schemes include a novel method for providing vertical displacement at the periphery of the aperture, a method for providing a continuous compliant support underneath the bimorph mirror, and a method for providing a three point support underneath the bimorph. In all three cases, there is no requirement for edge electrodes to provide the boundary conditions, resulting in devices of much higher bandwidth. The target is to broaden the use of these types of mirror beyond the current limits of either low order/low bandwidth, to address the high order, high bandwidth systems required by long range, horizontal path applications. This paper will discuss the different mirror designs, and present experimental results for the most recently assembled mirrors.

  7. Simple fabrication of gold nanobelts and patterns.

    PubMed

    Zhang, Renyun; Hummelgård, Magnus; Olin, Håkan

    2012-01-01

    Gold nanobelts are of interest in several areas; however, there are only few methods available to produce these belts. We report here on a simple evaporation induced self-assembly (EISA) method to produce porous gold nanobelts with dimensions that scale across nanometer (thickness ∼80 nm) and micrometer (width ∼20 µm), to decimeter (length ∼0.15 m). The gold nanobelts are well packed on the beaker wall and can be easily made to float on the surface of the solution for depositing onto other substrates. Microscopy showed that gold nanobelts had a different structure on the two sides of the belt; the density of gold nanowires on one side was greater than on the other side. Electrical measurements showed that these nanobelts were sensitive to compressive or tensile forces, indicating a potential use as a strain sensor. The patterned nanobelts were further used as a template to grow ZnO nanowires for potential use in applications such as piezo-electronics.

  8. Geometric Nonlinear Finite Element Analysis of Active Fibre Composite Bimorphs

    NASA Astrophysics Data System (ADS)

    Kernaghan, Robert

    Active fibre composite-actuated bimorphic actuators were studied in order to measure deflection performance. The deflection of the actuators was a function of the actuating electric potential applied to the active material as well as the magnitude of the axial preload applied to the bimorphic structure. This problem required the use of geometric nonlinear modeling techniques. Geometric nonlinear finite element analysis was undertaken to determine the deflection performance of Macro Fibre Composite (MFC)- and Hollow Active Fibre (HAFC)-actuated bimorphic structures. A physical prototype MFC-actuated bimorphic structure was manufactured in order to verify the results obtained by the finite element analysis. Theses analyses determined that the bimorphic actuators were capable of significant deflection. The analyses determined that the axial preload of the bimorphic actuators significantly amplified the deflection performance of the bimorphic actuators. The deflection performance of the bimorphic actuators suggest that they could be candidates to act as actuators for the morphing wing of a micro unmanned air vehicle.

  9. Membrane Mirrors With Bimorph Shape Actuators

    NASA Technical Reports Server (NTRS)

    Yang, Eui-Hyeok

    2003-01-01

    Deformable mirrors of a proposed type would be equipped with relatively-large-stroke microscopic piezoelectric actuators that would be used to maintain their reflective surfaces in precise shapes. These mirrors would be members of the class of MEMS-DM (for microelectromechanical system deformable mirror) devices, which offer potential for a precise optical control in adaptive-optics applications in such diverse fields as astronomy and vision science. The proposed mirror would be fabricated, in part, by use of a membrane-transfer technique. The actuator design would contain bimorph-type piezoelectric actuators.

  10. Flow Energy Piezoelectric Bimorph Nozzle Harvester

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart; Lee, Hyeong Jae; Kim, Namhyo; Sun, Kai; Corbett, Gary; Walkemeyer, Phillip; Hasenoehrl, Jennifer; Hall, Jeffery L.; Colonius, Tim; Tosi, Luis Phillipe; Arrazola, Alvaro

    2014-01-01

    There is a need for a long-life power generation scheme that could be used downhole in an oil well to produce 1 Watt average power. There are a variety of existing or proposed energy harvesting schemes that could be used in this environment but each of these has its own limitations. The vibrating piezoelectric structure is in principle capable of operating for very long lifetimes (decades) thereby possibly overcoming a principle limitation of existing technology based on rotating turbo-machinery. In order to determine the feasibility of using piezoelectrics to produce suitable flow energy harvesting, we surveyed experimentally a variety of nozzle configurations that could be used to excite a vibrating piezoelectric structure in such a way as to enable conversion of flow energy into useful amounts of electrical power. These included reed structures, spring mass-structures, drag and lift bluff bodies and a variety of nozzles with varying flow profiles. Although not an exhaustive survey we identified a spline nozzle/piezoelectric bimorph system that experimentally produced up to 3.4 mW per bimorph. This paper will discuss these results and present our initial analyses of the device using dimensional analysis and constitutive electromechanical modeling. The analysis suggests that an order-of-magnitude improvement in power generation from the current design is possible.

  11. Field Emission from Zinc Oxide Nanobelts.

    PubMed

    Asthanal, A; Yap, Y K; Shahbazian-Yassar, R

    2015-03-01

    We report here, the in-situ field emission (FE) property measurement on the individual ZnO nanobelts inside a high resolution transmission electron microscope (TEM) using a special scanning tunneling microscopy (STM)-TEM system. The field emission properties were found to be size scale dependent. It was found that the threshold voltage decreases and the field enhancement factor increases with the decrease in the diameter of the tip of the nanobelt and increase in the sharpness of the tip. The field emission parameter was estimated following the Fowler-Nordheim (F-N) theory. The ZnO nanobelt with the sharp agave like tip structure (d = 10 nm) showed the highest value of the field enhancement factor, β ≈ 4562, and a high field emission current of ~ 502 µA. PMID:26413652

  12. Nonlinear Vibrations of Ferroelectric Bimorph Cantilever

    NASA Astrophysics Data System (ADS)

    Ostrovskii, Igor; Nadtochiy, Andriy

    2008-06-01

    Nonlinear vibrations of a bimorph LiNbO3 microcantilever are investigated. A periodically poled LiNbO3 wafer is used as an initial chip. The cantilever is micro-machined near an interdomain wall between two inversely poled domains. The vibrations are excited by an applied rf-voltage, and motion of a cantilever tip is detected optically. Nonlinearity is revealed by measuring the changes in the dependencies of vibration amplitude versus frequency when amplitude increases, and by reading of sub-harmonic oscillations. A surface of the microcantilever may be modified with a silane, which is sensitive to certain biomolecules. This composite nonlinear micro-vibrator may be used for developing a smart biosensor operating in ambient atmosphere in a real time mode.

  13. Strongly birefringent pb3o2cl2 nanobelts.

    PubMed

    Sigman, Michael B; Korgel, Brian A

    2005-07-20

    Orthorhombic Pb3O2Cl2 (mendipite) nanobelts micrometers in length and tens of nanometers wide were synthesized by a solventless thermolysis of a single-source precursor in the presence of capping ligands. The nanobelts are single crystals elongated preferentially in the [010] direction. Pb3O2Cl2 is a birefringent material due to its anisotropic crystal structure. The nanobelts exhibit birefringence enhanced by 1 order of magnitude as a result of their small size and belt geometry exceeding the birefringence of naturally occurring minerals, including CaCO3 and TiO2. The preferential elongation of the nanobelts in the [010] direction contributes to this enhancement.

  14. Distributed Sensing and Shape Control of Piezoelectric Bimorph Mirrors

    SciTech Connect

    Redmond, James M.; Barney, Patrick S.; Henson, Tammy D.

    1999-07-28

    As part of a collaborative effort between Sandia National Laboratories and the University of Kentucky to develop a deployable mirror for remote sensing applications, research in shape sensing and control algorithms that leverage the distributed nature of electron gun excitation for piezoelectric bimorph mirrors is summarized. A coarse shape sensing technique is developed that uses reflected light rays from the sample surface to provide discrete slope measurements. Estimates of surface profiles are obtained with a cubic spline curve fitting algorithm. Experiments on a PZT bimorph illustrate appropriate deformation trends as a function of excitation voltage. A parallel effort to effect desired shape changes through electron gun excitation is also summarized. A one dimensional model-based algorithm is developed to correct profile errors in bimorph beams. A more useful two dimensional algorithm is also developed that relies on measured voltage-curvature sensitivities to provide corrective excitation profiles for the top and bottom surfaces of bimorph plates. The two algorithms are illustrated using finite element models of PZT bimorph structures subjected to arbitrary disturbances. Corrective excitation profiles that yield desired parabolic forms are computed, and are shown to provide the necessary corrective action.

  15. A bimorph flexural-disk accelerometer for underwater use

    SciTech Connect

    Moffett, M.B.; Powers, J.M.

    1996-04-01

    Design equations, based on Ralph Woollett{close_quote}s 1960 report [{open_quote}{open_quote}The Flexural Disk Transducer,{close_quote}{close_quote} U.S. Navy Underwater Sound Laboratory Research Report No. 490], are presented for a bimorph accelerometer. Figures-of-merit are compared for PZT-4, PZT-5A, PZT-5H, PZT-8 piezoceramics, and PVDF-TrFE copolymer. Neutrally buoyant, spherical and cylindrical accelerometer configurations can be designed to meet bandwidth, sensitivity, and depth requirements. Experimental results for PZT-8 bimorphs indicate that simply-supported edge conditions are easily achievable. {copyright} {ital 1996 American Institute of Physics.}

  16. Characterization of vibrating shape of a bimorph deformable mirror

    NASA Astrophysics Data System (ADS)

    Oya, Shin; Minowa, Yosuke; Hattori, Masayuki; Watanabe, Makoto; Hayano, Yutaka; Itoh, Megru; Saito, Yoshihiko; Takami, Hideki; Iye, Masanori; Guyon, Olivier; Colley, Stephen; Dinkins, Matthew; Eldred, Michael; Golota, Taras

    2008-07-01

    Actual measurement of vibrating shape of a bimorph deformable mirror is presented to discuss the characteristics of resonance. Understanding the vibration properties of a bimorph deformable mirror is a key issue to overcome resonance problem, a major drawback of this type of deformable mirror, and to make full use of its advantages. Two-dimensional vibrating shape of the deformable mirror surface, not only at a point, is essential to figure out the resonance behavior. The results are informative for improvement of mechanical design or control software.

  17. Optically Controlled Bimorph Cantilever of Poly(vinylidene difluoride)

    NASA Astrophysics Data System (ADS)

    Mizutani, Yasuhiro; Otani, Yukitoshi; Umeda, Norihiro

    2008-04-01

    Optically driven actuators are a non-contact method for the remote application of light energy. We propose a new optically driven actuator that employs bimorph poly(vinylidene difluoride) (PVDF) cantilevers. PVDF is an effective polymer from which to prepare actuators since it has both pyroelectric and piezoelectric properties. We have produced a bimorph cantilever from a PVDF film with a thin Ag electrode on one side. A bending model of the PVDF cantilever has been established and its bending characteristics have been experimentally measured. The mechanism can be explained by taking into consideration the model and its dielectric breakdown.

  18. Novel high-bandwidth bimorph deformable mirrors

    NASA Astrophysics Data System (ADS)

    Griffith, Michael S.; Laycock, Leslie C.; Archer, Nick J.

    2004-12-01

    Adaptive Optics (AO) is a critical underpinning technology for future laser delivery (including free-space optical communications), target illumination and imaging systems. It measures and compensates for optical distortion caused by transmission through the atmosphere, resulting in the ability to deploy smaller lasers and identify targets at greater ranges. One of the key components in an AO system is the wavefront modifier, which acts on the incoming or outgoing beam to counter the effects of the atmosphere. BAE SYSTEMS Advanced Technology Centre is developing multi-element bimorph deformable mirrors for such an applications. Our initial designs were based on a standard construction and exhibited a resonant frequency of 1kHz with a maximum stroke of +/-20μm for an active aperture of 50mm. These devices were limited by the necessity to have a 'dead space' between the inner active area and the mirror boundary; this ensured that both the requirements for the stroke and the fixed boundary conditions could be met simultaneously. However, there was a significant penalty to pay in terms of bandwidth, which is inversely proportional to the square of the full mirror diameter. In a series of iteration steps, we have created novel mounting arrangements that reduce dead space and thus provide the optimum trade-off between bandwidth and stroke. These schemes include supporting the mirror from underneath, rather than at its edge. As a result, models of 60mm active diameter mirrors predict a resonance in excess of 5kHz, combined with a maximum stroke greater than +/-40μm. This paper will discuss a number of different mirror designs and present experimental results for recently assembled devices.

  19. Optical sensor based on a single CdS nanobelt.

    PubMed

    Li, Lei; Yang, Shuming; Han, Feng; Wang, Liangjun; Zhang, Xiaotong; Jiang, Zhuangde; Pan, Anlian

    2014-04-23

    In this paper, an optical sensor based on a cadmium sulfide (CdS) nanobelt has been developed. The CdS nanobelt was synthesized by the vapor phase transportation (VPT) method. X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) results revealed that the nanobelt had a hexagonal wurtzite structure of CdS and presented good crystal quality. A single nanobelt Schottky contact optical sensor was fabricated by the electron beam lithography (EBL) technique, and the device current-voltage results showed back-to-back Schottky diode characteristics. The photosensitivity, dark current and the decay time of the sensor were 4 × 10⁴, 31 ms and 0.2 pA, respectively. The high photosensitivity and the short decay time were because of the exponential dependence of photocurrent on the number of the surface charges and the configuration of the back to back Schottky junctions.

  20. Syntax-Directed Translations and Quasi-alphabetic Tree Bimorphisms — Revisited

    NASA Astrophysics Data System (ADS)

    Maletti, Andreas; Tîrnăucă, Cătălin Ionuţ

    Quasi-alphabetic tree bimorphisms [ Steinby, Tîrnă ucă: Defining syntax-directed translations by tree bimorphisms. Theor. Comput. Sci., to appear. http://dx.doi.org/10.1016/j.tcs.2009.03.009 , 2009] are reconsidered. It is known that the class of (string) translations defined by such bimorphisms coincides with the class of syntax-directed translations. This result is extended to a smaller class of tree bimorphisms namely (linear and complete) symbol-to-symbol tree bimorphisms. Moreover, it is shown that the class of simple syntax-directed translations coincides with the class of translations defined by alphabetic tree bimorphisms (also known as finite-state relabelings). This proves that alphabetic tree bimorphisms are not sufficiently powerful to model all syntax-directed translations. Finally, it is shown that the class of tree transformations defined by quasi-alphabetic tree bimorphisms is closed under composition. The corresponding result is known in the variable-free case. Overall, the main results of [ Steinby, Tîrnă ucă] are strengthened.

  1. New Interfacial Nanochemistry on Sensory Bioscaffold-Membranes of Nanobelts

    NASA Astrophysics Data System (ADS)

    Chen, Feng

    Nanostructured bioscaffolds and biosensors are evolving as popular and powerful tools in life science and biotechnology, due to the possible control of their surface and structural properties at the nm-scale. Being seldom discussed in literature and long-underexploited in materials and biomedical sciences, development of nanofiber-based sensory bioscaffolds has great promises and grand challenges in finding an ideal platform for low-cost quantifications of biological and chemical species in real-time, label-free, and ultrasensitive fashion. In this study, titanate nanobelts were first of all synthesized, from hydrothermal reactions of a NaOH (or KOH solution) with TiO2 powder, to possess underexploited structure and surface vital to the rapid and label-free electrochemical detections of protein (cytochrome c) and neurotransmitter (dopamine). This work is based on a suite of new physical and chemical properties on the titanate nanobelt in water, including high surface area, zwitterionic surface, chemical- and photochemical-durability, cation-exchange and anion- and cation-sorption capacities, protein- and cell-compatibility, thermal-stability, and charge conductivity. The Fourier transform infrared (FTIR) was used for identifying any denaturing of the cytochrome c pre-immobilized on the titanate nanobelts. On that basis, the pheochromocytoma cells (PC-12 cell) were chosen to grow on the titanate nanobelts. These experiments prove that the sensory bioscaffolds of titanate nanobelt-membrane is a multiplex platform for developing new tools for energy, environmental and life sciences.

  2. Novel hybrid materials based on the vanadium oxide nanobelts

    NASA Astrophysics Data System (ADS)

    Zabrodina, G. S.; Makarov, S. G.; Kremlev, K. V.; Yunin, P. A.; Gusev, S. A.; Kaverin, B. S.; Kaverina, L. B.; Ketkov, S. Yu.

    2016-04-01

    Novel hybrid materials based on zinc phthalocyanine and nanostructured vanadium oxides have attracted extensive attention for the development of academic research and innovative industrial applications such as flexible electronics, optical sensors and heterogeneous catalysts. Vanadium oxides nanobelts were synthesized via a hydrothermal treatment V2O5·nH2O gel with surfactants (TBAB, CTAB) used as structure-directing agents, where CTAB - cetyltrimethylammonium bromide, TBAB - tetrabutylammonium bromide. Hybrid materials were prepared decoration of (CTA)0.33V2O5 flexible nanobelts with cationic zinc phthalocyanine by the ion-exchange route. Investigations of the thermal stability, morphologies and structures of the (CTA)0.33V2O5, (TBA)0.16V2O5 nanobelts and zinc phthalocyanine exchange product were carried out. The hybrid materials based on the nanostructured vanadium oxide and zinc phthalocyanine were tested as photocatalysts for oxidation of citronellol and 2-mercaptoethanol by dioxygen.

  3. Tailoring insoluble nanobelts into soluble anti-UV nanopotpourris

    NASA Astrophysics Data System (ADS)

    Wang, Jinmin; Sun, Xiao Wei; Jiao, Zhihui; Khoo, Eugene; Lee, Pooi See; Ma, Jan; Demir, Hilmi Volkan

    2011-11-01

    Soluble, transparent and anti-UV nanopotpourris have been prepared by tailoring long nanobelts. The strains and layered structures facilitate the breaking of the as-synthesized nanobelts under an applied mechanical action. The developed tailoring process of nanobelts is a general top-down secondary processing of layered nanostructures at the nanoscale level, which can be expended to the modifications of layered nanowires, nanotubes and hierarchical nanostructures. By tailoring, the size, morphology and solubility are modified, which may open up an area of advanced processing of nanomaterials and hint at some potential applications. Because of the excellent solubility of the tailored nanopotpourris, they are easily dispersed in cosmetics or polymer films, which are quite useful for some anti-UV protection applications, such as anti-UV sunscreen creams and anti-UV window films for vehicles and buildings.

  4. Bimorph micro heat engines based on carbon nanotube freestanding films

    NASA Astrophysics Data System (ADS)

    Ikuno, Takashi; Fukano, Tatsuo; Higuchi, Kazuo; Takeda, Yasuhiko

    2015-11-01

    We have found that lightweight bimorph strips consisting of multiwalled carbon nanotube freestanding films (MWNT-FSFs) and Ni thin films exhibit a continuous bending-stretching motion on a hot plate even below the temperature of 100 °C in an environment at room temperature. In fact, the Ni/MWNT-FSFs exhibited this motion at a temperature difference of as small as 5 °C. The requirements of this motion have been qualitatively elucidated by a simulation based on a relaxation time approximation.

  5. Piezoelectric Bimorph Cantilever for Vibration-Producing-Hydrogen

    PubMed Central

    Zhang, Jun; Wu, Zheng; Jia, Yanmin; Kan, Junwu; Cheng, Guangming

    2013-01-01

    A device composed of a piezoelectric bimorph cantilever and a water electrolysis device was fabricated to realize piezoelectrochemical hydrogen production. The obvious output of the hydrogen and oxygen through application of a mechanical vibration of ∼0.07 N and ∼46.2 Hz was observed. This method provides a cost-effective, recyclable, environment-friendly and simple way to directly split water for hydrogen fuels by scavenging mechanical waste energy forms such as noise or traffic vibration in the environment. PMID:23271601

  6. Extracting nanobelt mechanical properties from nanoindentation

    NASA Astrophysics Data System (ADS)

    Zhang, Yin

    2010-06-01

    A three-spring-in-series model is proposed for the nanobelt (NB) indentation test. Compared with the previous two-spring-in-series model, which considers the bending stiffness of atomic force microscope cantilever and the indenter/NB contact stiffness, this model adds a third spring of the NB/substrate contact stiffness. NB is highly flexural due to its large aspect ratio of length to thickness. The bending and lift-off of NB form a localized contact with substrate, which makes the Oliver-Pharr method [W. C. Oliver and G. M. Pharr, J. Mater. Res. 7, 1564 (1992)] and Sneddon method [I. N. Sneddon, Int. J. Eng. Sci. 3, 47 (1965)] inappropriate for NB indentation test. Because the NB/substrate deformation may have significant impact on the force-indentation depth data obtained in experiment, the two-spring-in-series model can lead to erroneous predictions on the NB mechanical properties. NB in indentation test can be susceptible to the adhesion influence because of its large surface area to volume ratio. NB/substrate contact and adhesion can have direct and significant impact on the interpretation of experimental data. Through the three-spring-in-series model, the influence of NB/substrate contact and adhesion is analyzed and methods of reducing such influence are also suggested.

  7. New configurations of oscillatory flow pumps using bimorph piezoelectric actuators

    NASA Astrophysics Data System (ADS)

    Vatanabe, Sandro L.; Pires, Rogério F.; Nakasone, Paulo H.; Silva, Emílio C. N.

    2008-03-01

    Precision flow pumps have been widely studied over the last three decades. They have been applied in the areas of Biology, Pharmacy and Medicine in applications usually related to the dosage of medicine and chemical reagents. In addition, thermal management solutions for electronic devices have also been recently developed using these kinds of pumps offering better performance with low noise and low power consumption. In previous works was presented the working principle of a pump based on the use of a bimorph piezoelectric actuator inserted in a fluid channel to generate flow. This work presents a novel configuration of piezoelectric flow pumps using a bimorph piezoelectric actuator of different aspect ratio. Sensibility studies of the rectangular cross-sectional area channel are conducted computationally (CFD) and three parameters are investigated: resonance frequency and oscillation amplitude of the piezoelectric actuator, and pressure inside the channel. Also, experimental tests are conducted to verify the influence of clamps' rigidity and actuator's insulator. The experimental results show that improving these two aspects it is possible to achieve higher flow rates.

  8. Viability study of oscillatory flow pumps using bimorph piezoelectric actuators

    NASA Astrophysics Data System (ADS)

    Vatanabe, Sandro L.; Pires, Rogério F.; Choi, Andres; Nakasone, Paulo H.; Silva, Emílio C. N.

    2007-04-01

    Precision flow pumps have been widely studied over the last three decades. They have been applied in the areas of Biology, Pharmacy and Medicine in applications usually related to the dosage of medicine and chemical reagents. In addition, thermal management solutions for electronic devices have also been recently developed using these kinds of pumps offering better performance with low noise and low power consumption. In a previous work, the working principle of a pump based on the use of a bimorph piezoelectric actuator inserted in a fluid channel to generate flow was presented. In this work, a novel configuration of this piezoelectric flow pump that consists of a flow pump using two bimorph piezoelectric actuators in parallel configuration has been studied and it is presented. This configuration was inspired on fish swimming modes. The complete cycle of pump development was conducted, consisting in designing, manufacturing, and experimental characterization steps. Load-loss and flow rate characterization experimental tests were conducted, generating data that allows us to analyze the influence of geometric parameters in the pump performance. Comparisons among numerical and experimental results were made to validate the computational results and improve the accuracy of the implemented models.

  9. Cation Exchange Synthesis and Unusual Resistive Switching Behaviors of Ag2Se Nanobelts.

    PubMed

    Guo, Zheng; Li, Min-Qiang; Liu, Jin-Huai; Huang, Xing-Jiu

    2015-12-16

    Ag2Se nanobelts are prepared through employing ZnSe nanobelts as templates via a facile cation exchange approach. The templates are derived from precursor ZnSe·0.5N2 H4 nanobelts, which are synthesized by a simple hydrothermal method. As-synthesized precursor nanobelts are with 200 nm in width and several hundreds of micrometers in length. Annealed in N2 , they are transformed into ZnSe nanobelts with preserving their initial morphology. Following with a complete replacement of Zn(2+) by Ag(+), Ag2Se nanobelts with single crystalline are obtained via a cation-exchange reaction. Combined with the Langmuir-Blodgett assembly technique, regular films of ZnSe nanobelts can be achieved on transparent glass substrates and Si wafers with interdigital Au electrode arrays. Further, the optical and electrical evolutions are investigated from ZnSe nanobelts to Ag2 Se nanobelts. Finally, the resistive switching characteristic are carefully explored for Ag2Se nanobelts regularly arranged on interdigital Au microelectrodes. The results indicate that it is analogous to complementary resistive switching behaviors, which is different from that of traditional two terminal devices about previously reported Ag2Se. In order to clarify this phenomenon, a possible mechanism has been proposed and indirectly demonstrated through in situ SEM (scanning electron microscropy) observation.

  10. Enhanced Magnetoelectric Coupling in Layered Structure of Piezoelectric Bimorph and Metallic Alloy

    NASA Astrophysics Data System (ADS)

    Petrov, V. M.; Bichurin, M. I.; Lavrentyeva, K. V.; Leontiev, V. S.

    2016-08-01

    We have investigated the enhanced magnetoelectric (ME) coupling in a layered structure of piezoelectric bimorph and magnetostrictive metallic alloy. The observed ME coefficient in the piezoelectric bimorph-based structure was found to be two times higher than in the traditional piezoelectric/magnetostrictive bilayer. The observed enhancement in ME coupling strength is related to equal signs of induced voltage in both lead zirconate titanate layers with opposite poling directions due to the flexural deformations. The piezoelectric bimorph-based structure has promising potential for sensor and technological applications.

  11. Modeling and analysis of the thermal effects of a circular bimorph piezoelectric actuator.

    PubMed

    Wang, Hairen; Yang, Shengfeng

    2016-02-01

    A theoretical analysis of the thermal effects of a circular bimorph piezoelectric actuator (CBPA) was performed. The circular bimorph structure consists of two flexible piezoelectric ceramic layers and one metallic layer in the middle, and is powered to produce flexural deformation. The CBPA, which may be a good match for large adaptive optics telescopes, has a large stroke and a high resonance frequency. We have derived analytical solutions (both the static solution and the dynamic solution) of the thermal effects of introducing (and increasing the thickness of) a metallic layer into the bimorph. Numerical results are presented to illustrate the dependence of the CBPA's performance upon the physical parameters. PMID:26836094

  12. Porous and single-crystalline ZnO nanobelts: fabrication with annealing precursor nanobelts, and gas-sensing and optoelectronic performance

    NASA Astrophysics Data System (ADS)

    Jin, Xiao-Bo; Li, Yi-Xiang; Su, Yao; Guo, Zheng; Gu, Cui-Ping; Huang, Jia-Rui; Meng, Fan-Li; Huang, Xing-Jiu; Li, Min-Qiang; Liu, Jin-Huai

    2016-09-01

    Porous and single-crystalline ZnO nanobelts have been prepared through annealing precursors of ZnSe · 0.5N2H4 well-defined and smooth nanobelts, which have been synthesized via a simple hydrothermal method. The composition and morphology evolutions with the calcination temperatures have been investigated in detail for as-prepared precursor nanobelts, suggesting that they can be easily transformed into ZnO nanobelts by preserving their initial morphology via calcination in air. In contrast, the obtained ZnO nanobelts are densely porous, owing to the thermal decomposition and oxidization of the precursor nanobelts. More importantly, the achieved porous ZnO nanobelts are single-crystalline, different from previously reported ones. Motivated by the intrinsic properties of the porous structure and good electronic transporting ability of single crystals, their gas-sensing performance has been further explored. It is demonstrated that porous ZnO single-crystalline nanobelts exhibit high response and repeatability toward volatile organic compounds, such as ethanol and acetone, with a short response/recovery time. Furthermore, their optoelectronic behaviors indicate that they can be promisingly employed to fabricate photoelectrochemical sensors.

  13. Porous and single-crystalline ZnO nanobelts: fabrication with annealing precursor nanobelts, and gas-sensing and optoelectronic performance.

    PubMed

    Jin, Xiao-Bo; Li, Yi-Xiang; Su, Yao; Guo, Zheng; Gu, Cui-Ping; Huang, Jia-Rui; Meng, Fan-Li; Huang, Xing-Jiu; Li, Min-Qiang; Liu, Jin-Huai

    2016-09-01

    Porous and single-crystalline ZnO nanobelts have been prepared through annealing precursors of ZnSe · 0.5N2H4 well-defined and smooth nanobelts, which have been synthesized via a simple hydrothermal method. The composition and morphology evolutions with the calcination temperatures have been investigated in detail for as-prepared precursor nanobelts, suggesting that they can be easily transformed into ZnO nanobelts by preserving their initial morphology via calcination in air. In contrast, the obtained ZnO nanobelts are densely porous, owing to the thermal decomposition and oxidization of the precursor nanobelts. More importantly, the achieved porous ZnO nanobelts are single-crystalline, different from previously reported ones. Motivated by the intrinsic properties of the porous structure and good electronic transporting ability of single crystals, their gas-sensing performance has been further explored. It is demonstrated that porous ZnO single-crystalline nanobelts exhibit high response and repeatability toward volatile organic compounds, such as ethanol and acetone, with a short response/recovery time. Furthermore, their optoelectronic behaviors indicate that they can be promisingly employed to fabricate photoelectrochemical sensors. PMID:27454792

  14. Suspended microfluidics.

    PubMed

    Casavant, Benjamin P; Berthier, Erwin; Theberge, Ashleigh B; Berthier, Jean; Montanez-Sauri, Sara I; Bischel, Lauren L; Brakke, Kenneth; Hedman, Curtis J; Bushman, Wade; Keller, Nancy P; Beebe, David J

    2013-06-18

    Although the field of microfluidics has made significant progress in bringing new tools to address biological questions, the accessibility and adoption of microfluidics within the life sciences are still limited. Open microfluidic systems have the potential to lower the barriers to adoption, but the absence of robust design rules has hindered their use. Here, we present an open microfluidic platform, suspended microfluidics, that uses surface tension to fill and maintain a fluid in microscale structures devoid of a ceiling and floor. We developed a simple and ubiquitous model predicting fluid flow in suspended microfluidic systems and show that it encompasses many known capillary phenomena. Suspended microfluidics was used to create arrays of collagen membranes, mico Dots (μDots), in a horizontal plane separating two fluidic chambers, demonstrating a transwell platform able to discern collective or individual cellular invasion. Further, we demonstrated that μDots can also be used as a simple multiplexed 3D cellular growth platform. Using the μDot array, we probed the combined effects of soluble factors and matrix components, finding that laminin mitigates the growth suppression properties of the matrix metalloproteinase inhibitor GM6001. Based on the same fluidic principles, we created a suspended microfluidic metabolite extraction platform using a multilayer biphasic system that leverages the accessibility of open microchannels to retrieve steroids and other metabolites readily from cell culture. Suspended microfluidics brings the high degree of fluidic control and unique functionality of closed microfluidics into the highly accessible and robust platform of open microfluidics.

  15. Highly Polarized and Self-Waveguided Emission from Single-Crystalline Organic Nanobelts

    SciTech Connect

    Che, Yanke; Yang, Xiaomei; Balakrishnan, Kaushik; Zuo, Jianmin; Zang, Ling

    2009-09-15

    Well-defined single-crystalline nanobelts with strong fluorescence were fabricated from a perylene tetracarboxylic diimide molecule modified with specific side-chains that afford flip-flap stacking, rather than the common translated stacking, between the molecules along the long axis of the nanobelt. The nanobelts thus fabricated possess highly polarized, self-waveguided emission, making them ideal candidates for application in nanolasers and other angle-dependent optical nanodevices.

  16. Large-scale growth of millimeter-long single-crystalline ZnS nanobelts

    SciTech Connect

    Li Jianye Zhang Qi; An Lei; Qin Luchang; Liu Jie

    2008-11-15

    Millimeter-long single-crystalline hexagonal ZnS nanobelts were grown on specific locations on a wafer scale. This is the first time that the millimeter-scale ZnS nanobelt has been synthesized. The longest nanobelts are about 3 mm. The as-grown nanobelts were characterized by means of field emission scanning electron microscopy, X-ray powder diffraction, high-resolution transmission electron microscopy, and selected area electron diffraction. The results indicate that the ultra-long nanobelts are pure single-crystalline hexagonal ZnS. There are two kinds of ZnS nanobelts existing in the products. One is the nanobelts that have two smooth sides and grow along the [0 0 1] longitudinal direction, and the other is the nanobelts that have one smooth side and one saw-teeth-like side, namely nanosaws, and grow along the [2 1 0] longitudinal direction. A vapor-liquid-solid mechanism is suggested for the lengthwise growth of the ZnS nanobelts (nanosaws) and a vapor-solid mechanism for the side direction growth of the saw-teeth of the nanosaws. - Graphical Abstract: Millimeter-long single-crystalline ZnS nanobelts were grown on specific locations on a large scale. There are two kinds of nanobelts in the products-one has two smooth sides, and the other has one smooth side and one saw-teeth-like side, namely nanosaws. Mechanisms for the longitudinal direction growth of the nanobelts/nanosaws and the side saw-teeth direction growth of the nanosaws are discussed.

  17. Correction: β-Sialon nanowires, nanobelts and hierarchical nanostructures: morphology control, growth mechanism and cathodoluminescence properties

    NASA Astrophysics Data System (ADS)

    Huang, Juntong; Huang, Zhaohui; Liu, Yangai; Fang, Minghao; Chen, Kai; Huang, Yaoting; Huang, Saifang; Ji, Haipeng; Yang, Jingzhou; Wu, Xiaowen; Zhang, Shaowei

    2016-07-01

    Correction for `β-Sialon nanowires, nanobelts and hierarchical nanostructures: morphology control, growth mechanism and cathodoluminescence properties' by Juntong Huang, et al., Nanoscale, 2014, 6, 424-432.

  18. Temperature effect on electrospinning of nanobelts: the case of hafnium oxide.

    PubMed

    Su, Yurong; Lu, Bingan; Xie, Yizhu; Ma, Ziwei; Liu, Lixin; Zhao, Haiting; Zhang, Jia; Duan, Huigao; Zhang, Hongliang; Li, Jian; Xiong, Yuqing; Xie, Erqing

    2011-07-15

    Electrospinning is a convenient and versatile method for fabricating different kinds of one-dimensional nanostructures such as nanofibres, nanotubes and nanobelts. Environmental parameters have a great influence on the electrospinning nanostructure. Here we report a new method to fabricate hafnium oxide (HfO(2)) nanobelts. HfO(2) nanobelts were prepared by electrospinning a sol-gel solution with the implementation of heating and subsequent calcination treatment. We investigate the temperature dependence of the products by scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and energy-dispersive x-ray (EDX) spectroscopy. The heating temperature of spinning ambient is found to be crucial to the formation of HfO(2) nanobelts. By tuning the temperature, the morphological transformation of HfO(2) from nanowires to nanobelts was achieved. It was found that the rapid evaporation of solvent played an important role in the formation process of HfO(2) nanobelts. It is shown that nanobelts can only be obtained with the temperature higher than 50 °C and they are in the high quality monoclinic phase. A possible growth mechanism of the nanobelts based on phase separation is proposed. The enhanced photoluminescence (PL) of HfO(2):Eu(3+) nanobelts is also illustrated. PMID:21659687

  19. Large-scale growth of millimeter-long single-crystalline ZnS nanobelts

    NASA Astrophysics Data System (ADS)

    Li, Jianye; Zhang, Qi; An, Lei; Qin, Luchang; Liu, Jie

    2008-11-01

    Millimeter-long single-crystalline hexagonal ZnS nanobelts were grown on specific locations on a wafer scale. This is the first time that the millimeter-scale ZnS nanobelt has been synthesized. The longest nanobelts are about 3 mm. The as-grown nanobelts were characterized by means of field emission scanning electron microscopy, X-ray powder diffraction, high-resolution transmission electron microscopy, and selected area electron diffraction. The results indicate that the ultra-long nanobelts are pure single-crystalline hexagonal ZnS. There are two kinds of ZnS nanobelts existing in the products. One is the nanobelts that have two smooth sides and grow along the [0 0 1] longitudinal direction, and the other is the nanobelts that have one smooth side and one saw-teeth-like side, namely nanosaws, and grow along the [2 1 0] longitudinal direction. A vapor-liquid-solid mechanism is suggested for the lengthwise growth of the ZnS nanobelts (nanosaws) and a vapor-solid mechanism for the side direction growth of the saw-teeth of the nanosaws.

  20. Temperature effect on electrospinning of nanobelts: the case of hafnium oxide.

    PubMed

    Su, Yurong; Lu, Bingan; Xie, Yizhu; Ma, Ziwei; Liu, Lixin; Zhao, Haiting; Zhang, Jia; Duan, Huigao; Zhang, Hongliang; Li, Jian; Xiong, Yuqing; Xie, Erqing

    2011-07-15

    Electrospinning is a convenient and versatile method for fabricating different kinds of one-dimensional nanostructures such as nanofibres, nanotubes and nanobelts. Environmental parameters have a great influence on the electrospinning nanostructure. Here we report a new method to fabricate hafnium oxide (HfO(2)) nanobelts. HfO(2) nanobelts were prepared by electrospinning a sol-gel solution with the implementation of heating and subsequent calcination treatment. We investigate the temperature dependence of the products by scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and energy-dispersive x-ray (EDX) spectroscopy. The heating temperature of spinning ambient is found to be crucial to the formation of HfO(2) nanobelts. By tuning the temperature, the morphological transformation of HfO(2) from nanowires to nanobelts was achieved. It was found that the rapid evaporation of solvent played an important role in the formation process of HfO(2) nanobelts. It is shown that nanobelts can only be obtained with the temperature higher than 50 °C and they are in the high quality monoclinic phase. A possible growth mechanism of the nanobelts based on phase separation is proposed. The enhanced photoluminescence (PL) of HfO(2):Eu(3+) nanobelts is also illustrated.

  1. Controllable synthesis of ultrathin vanadium oxide nanobelts via an EDTA-mediated hydrothermal process

    NASA Astrophysics Data System (ADS)

    Yu-Xiang, Qin; Cheng, Liu; Wei-Wei, Xie; Meng-Yang, Cui

    2016-02-01

    Ultrathin VO2 nanobelts with rough alignment features are prepared on the induction layer-coated substrates by an ethylenediaminetetraacetic acid (EDTA)-mediated hydrothermal process. EDTA acts as a chelating reagent and capping agent to facilitate the one-dimensional (1D) preferential growth of ultrathin VO2 nanobelts with high crystallinities and good uniformities. The annealed induction layer and concentration of EDTA are found to play crucial roles in the formation of aligned and ultrathin nanobelts. Variation in EDTA concentration can change the VO2 morphology of ultrathin nanobelts into that of thick nanoplates. Mild annealing of ultrathin VO2 nanobelts at 350 °C in air results in the formation of V2O5 nanobelts with a nearly unchanged ultrathin structure. The nucleation and growth mechanism involved in the formations of nanobelts and nanoplates are proposed. The ethanol gas sensing properties of the V2O5 nanobelt networks-based sensor are investigated in a temperature range from 100 °C to 300 °C over ethanol concentrations ranging from 3 ppm to 500 ppm. The results indicate that the V2O5 nanobelt network sensor exhibits high sensitivity, good reversibility, and fast response-recovery characteristics with an optimal working temperature of 250 °C. Project supported by the National Natural Science Foundation of China (Grant Nos. 61274074, 61271070, and 61574100).

  2. A Graphene-Based Bimorph Structure for Design of High Performance Photoactuators.

    PubMed

    Hu, Ying; Wu, Guan; Lan, Tian; Zhao, Jingjing; Liu, Yang; Chen, Wei

    2015-12-16

    A photoactuator based on a tubular-shaped graphene composite bimorph is fabricated and shows reversible photoactuation with fast response and large deformation (deformation angle of ca. 479° in only 3.6 s), which is mostly attributed to the interfacial thermal stress. Various photoactuator devices based on the tubular bimorph, including a smart box and crawler-type robot that can mimic tank-track motion, are designed. PMID:26498737

  3. Optoelectronic characteristics of single CdS nanobelts

    SciTech Connect

    Li, Q.H.; Gao, T.; Wang, T.H.

    2005-05-09

    Optoelectronic properties of single CdS nanobelts are investigated by performing transport measurements with different laser ON/OFF circles. The current increases linearly with the bias voltage in the dark, and superlinearly under illumination. The superlinear increase can be related to the enhanced mobility due to the partial release of surface adsorbates under illumination. The current jumps up by five orders of magnitude upon turning on the laser with an intensity of 0.3 W/cm{sup 2} within 91 ms and decreases by five orders 6 ms just after turning off the laser. The high sensitivity and fast response in the visible range indicate potential applications of CdS nanobelts in realizing optoelectronic switches.

  4. Single-ZnO-Nanobelt-Based Single-Electron Transistors

    NASA Astrophysics Data System (ADS)

    Ji, Xiao-Fan; Xu, Zheng; Cao, Shuo; Qiu, Kang-Sheng; Tang, Jing; Zhang, Xi-Tian; Xu, Xiu-Lai

    2014-06-01

    We fabricate single electron transistors based on a single ZnO nanobelt using standard micro-fabrication techniques. The transport properties of the devices are characterized at room temperature and at low temperature (4.2 K). At room temperature, the source-drain current increases linearly as the bias voltage increases, indicating a good ohmic contact in the transistors. At 4.2 K, a Coulomb blockade regime is observed up to a bias voltage of a few millivolts. With scanning the back gate voltage, Coulomb oscillations can be clearly resolved with a period around 1 V. From the oscillations, the charging energy for the single electron transistor is calculated to be about 10 meV, which suggests that confined quantum dots exist with sizes around 35 nm in diameter. The irregular Coulomb diamonds are observed due to the multi-tunneling junctions between dots in the nanobelt.

  5. Taming excitons in II-VI semiconductor nanowires and nanobelts

    NASA Astrophysics Data System (ADS)

    Xu, Xinlong; Zhang, Qing; Zhang, Jun; Zhou, Yixuan; Xiong, Qihua

    2014-10-01

    Excitons are one of the most important fundamental quasi-particles, and are involved in a variety of processes forming the basis of a wide range of opto-electronic and photonic devices based on II-VI semiconductor nanowires and nanobelts, such as light-emitting diodes, photovoltaic cells, photodetectors and nanolasers. A clear understanding of their properties and unveiling the potential engineering for excitons is of particular importance for the design and optimization of nanoscale opto-electronic and photonic devices. Herein, we present a comprehensive review on discussing the fundamental behaviours of the excitons in one-dimensional (1D) II-VI semiconductor nanomaterials (nanowires and nanobelts). We will start with a focus on the unique properties (origin, generation, etc) and dynamics of excitons and exciton complexes in the II-VI semiconductor nanowires and nanobelts. Then we move to the recent progress on the excitonic response in 1D nanomaterials and focus on the tailoring and engineering of excitonic properties through rational controlling of the physical parameters and conditions, intrinsically and extrinsically. These include (1) exciton-exciton interaction, which is important for 1D nanomaterial nanolasing; (2) exciton-phonon interaction, which has interesting applications for laser cooling; and (3) exciton-plasmon interaction, which is the cornerstone towards the realization of plasmonic lasers. The potential of electric field, morphology and size control for excitonic properties is also discussed. Unveiling and controlling excitonic properties in II-VI semiconductor nanowires and nanobelts would promote the development of 1D nanoscience and nanotechnology.

  6. Sb(2)O(3) nanobelt networks for excellent visible-light-range photodetectors.

    PubMed

    Li, L; Zhang, Y X; Fang, X S; Zhai, T Y; Liao, M Y; Wang, H Q; Li, G H; Koide, Y; Bando, Y; Golberg, D

    2011-04-22

    Excellent photoconductive properties have been found in Sb(2)O(3) nanobelts synthesized by a surfactant-assisted solvothermal method. Visible-light photodetectors have been designed from Sb(2)O(3) nanobelt networks using micrometer-wide gold wires as masks. Photodetectors show high sensitivity to visible light, high stability, and reproducibility. Fast response and decay times (<0.3 s) are comparable or even better than these parameters in many other metal oxide nanoscale photodetectors. The dominant mechanism of excellent photoconductivity is attributed to the barrier height modulations in the nanobelt-to-nanobelt contact regions. These results demonstrate that Sb(2)O(3) nanobelt networks can indeed serve as high-performance photodetectors in the visible light range.

  7. Highly-stable silver nanobelts joined via diffusion-free attachment.

    PubMed

    Rivers, Geoff; Marzbanrad, Ehsan; Hook, Michael David; Lee-Sullivan, Pearl; Zhou, Y Norman; Zhao, Boxin

    2016-07-22

    Silver nanobelts are demonstrated here to undergo inter-particle joining at relatively low temperatures of less than 180 °C. For surface-coated networks of nanobelts this joining reduced the network sheet resistance by 95%. The joining mechanism appears to be non-diffusional oriented attachment, caused by the thermal reactivation of the halted oriented attachment mechanism that occurred originally at room temperature during the rapid nanobelt synthesis. This self-assembly mechanism was explored by in situ electrical and calorimetric experiments, and supported by electron microscopy. Unlike pentagonal silver nanowires, silver nanobelts do not rely on diffusional instability to achieve workably low joining temperatures. The oriented attachment displayed by nanobelts represents a new approach to achieving valuable reductions in network resistance, disentangled from the instability and diffusion-driven failure by nanoparticle degradation displayed by competing silver nanoparticles. PMID:27292376

  8. Highly-stable silver nanobelts joined via diffusion-free attachment

    NASA Astrophysics Data System (ADS)

    Rivers, Geoff; Marzbanrad, Ehsan; Hook, Michael David; Lee-Sullivan, Pearl; Zhou, Y. Norman; Zhao, Boxin

    2016-07-01

    Silver nanobelts are demonstrated here to undergo inter-particle joining at relatively low temperatures of less than 180 °C. For surface-coated networks of nanobelts this joining reduced the network sheet resistance by 95%. The joining mechanism appears to be non-diffusional oriented attachment, caused by the thermal reactivation of the halted oriented attachment mechanism that occurred originally at room temperature during the rapid nanobelt synthesis. This self-assembly mechanism was explored by in situ electrical and calorimetric experiments, and supported by electron microscopy. Unlike pentagonal silver nanowires, silver nanobelts do not rely on diffusional instability to achieve workably low joining temperatures. The oriented attachment displayed by nanobelts represents a new approach to achieving valuable reductions in network resistance, disentangled from the instability and diffusion-driven failure by nanoparticle degradation displayed by competing silver nanoparticles.

  9. Symmetry Breaking by Surface Blocking: Synthesis of Bimorphic Silver Nanoparticles, Nanoscale Fishes and Apples.

    PubMed

    Cathcart, Nicole; Kitaev, Vladimir

    2016-01-01

    A powerful approach to augment the diversity of well-defined metal nanoparticle (MNP) morphologies, essential for MNP advanced applications, is symmetry breaking combined with seeded growth. Utilizing this approach enabled the formation of bimorphic silver nanoparticles (bi-AgNPs) consisting of two shapes linked by one regrowth point. Bi-AgNPs were formed by using an adsorbing polymer, poly(acrylic acid), PAA, to block the surface of a decahedral AgNP seed and restricting growth of new silver to a single nucleation point. First, we have realized 2-D growth of platelets attached to decahedra producing nanoscale shapes reminiscent of apples, fishes, mushrooms and kites. 1-D bimorphic growth of rods (with chloride) and 3-D bimorphic growth of cubes and bipyramids (with bromide) were achieved by using halides to induce preferential (100) stabilization over (111) of platelets. Furthermore, the universality of the formation of bimorphic nanoparticles was demonstrated by using different seeds. Bi-AgNPs exhibit strong SERS enhancement due to regular cavities at the necks. Overall, the reported approach to symmetry breaking and bimorphic nanoparticle growth offers a powerful methodology for nanoscale shape design. PMID:27605125

  10. Tailoring of the thermomechanical performance of VO2 nanowire bimorph actuators by ion implantation

    NASA Astrophysics Data System (ADS)

    Karl, H.; Peyinghaus, S. C.

    2015-12-01

    Vanadium dioxide VO2 nanowire bimorph actuators work on the basis of the large abrupt length change at the metal-insulator phase transition (MIT). A key parameter for the bimorph performance and efficiency is the bending curvature and the width of the temperature hysteresis of the MIT which is inherently large for single domain VO2 metal side coated nanowires. In this work we present single-clamped Ir side coated VO2 bimorphs which show unprecedented high bending curvatures of up to 105 m-1 and new type of side ion-implanted VO2 nanowire bimorph actuators with a nearly completely suppressed temperature hysteresis. It is assumed that ion-beam induced radiation defects in the VO2 crystal structure act as nucleation sites for the MIT. Moreover it will be shown that mechanical strain intentionally built-in during VO2 nanowire bimorph fabrication allows to direct phase transformation via a strain stabilized metastable phase and thus allows to control bending response on temperature change.

  11. Symmetry Breaking by Surface Blocking: Synthesis of Bimorphic Silver Nanoparticles, Nanoscale Fishes and Apples

    NASA Astrophysics Data System (ADS)

    Cathcart, Nicole; Kitaev, Vladimir

    2016-09-01

    A powerful approach to augment the diversity of well-defined metal nanoparticle (MNP) morphologies, essential for MNP advanced applications, is symmetry breaking combined with seeded growth. Utilizing this approach enabled the formation of bimorphic silver nanoparticles (bi-AgNPs) consisting of two shapes linked by one regrowth point. Bi-AgNPs were formed by using an adsorbing polymer, poly(acrylic acid), PAA, to block the surface of a decahedral AgNP seed and restricting growth of new silver to a single nucleation point. First, we have realized 2-D growth of platelets attached to decahedra producing nanoscale shapes reminiscent of apples, fishes, mushrooms and kites. 1-D bimorphic growth of rods (with chloride) and 3-D bimorphic growth of cubes and bipyramids (with bromide) were achieved by using halides to induce preferential (100) stabilization over (111) of platelets. Furthermore, the universality of the formation of bimorphic nanoparticles was demonstrated by using different seeds. Bi-AgNPs exhibit strong SERS enhancement due to regular cavities at the necks. Overall, the reported approach to symmetry breaking and bimorphic nanoparticle growth offers a powerful methodology for nanoscale shape design.

  12. Piezoelectric Bimorphs' Characteristics as In-Socket Sensors for Transfemoral Amputees

    PubMed Central

    El-Sayed, Amr M.; Hamzaid, Nur Azah; Osman, Noor Azuan Abu

    2014-01-01

    Alternative sensory systems for the development of prosthetic knees are being increasingly highlighted nowadays, due to the rapid advancements in the field of lower limb prosthetics. This study presents the use of piezoelectric bimorphs as in-socket sensors for transfemoral amputees. An Instron machine was used in the calibration procedure and the corresponding output data were further analyzed to determine the static and dynamic characteristics of the piezoelectric bimorph. The piezoelectric bimorph showed appropriate static operating range, repeatability, hysteresis, and frequency response for application in lower prosthesis, with a force range of 0–100 N. To further validate this finding, an experiment was conducted with a single transfemoral amputee subject to measure the stump/socket pressure using the piezoelectric bimorph embedded inside the socket. The results showed that a maximum interface pressure of about 27 kPa occurred at the anterior proximal site compared to the anterior distal and posterior sites, consistent with values published in other studies. This paper highlighted the capacity of piezoelectric bimorphs to perform as in-socket sensors for transfemoral amputees. However, further experiments are recommended to be conducted with different amputees with different socket types. PMID:25513823

  13. A spongy graphene based bimorph actuator with ultra-large displacement towards biomimetic application.

    PubMed

    Hu, Ying; Lan, Tian; Wu, Guan; Zhu, Zicai; Chen, Wei

    2014-11-01

    Bimorph actuators, consisting of two layers with asymmetric expansion and generating bending displacement, have been widely researched. Their actuation performances greatly rely on the difference of coefficients of thermal expansion (CTE) between the two material layers. Here, by introducing a spongy graphene (sG) paper with a large negative CTE as well as high electrical-to-thermal properties, an electromechanical sG/PDMS bimorph actuator is designed and fabricated, showing an ultra-large bending displacement output under low voltage stimulation (curvature of about 1.2 cm(-1) at 10 V for 3 s), a high displacement-to-length ratio (∼0.79), and vibration motion at AC voltage (up to 10 Hz), which is much larger and faster than that of the other electromechanical bimorph actuators. Based on the sG/PDMS bimorph serving as the "finger", a mechanical gripper is constructed to realize the fast manipulation of the objects under 0.1 Hz square wave voltage stimulation (0-8 V). The designed bimorph actuator coupled with ultra-large bending displacement, low driven voltage, and the ease of fabrication may open up substantial possibilities for the utilization of electromechanical actuators in practical biomimetic device applications. PMID:25220910

  14. Characterization of a next-generation piezo bimorph X-ray mirror for synchrotron beamlines

    PubMed Central

    Alcock, Simon G.; Nistea, Ioana; Sutter, John P.; Sawhney, Kawal; Fermé, Jean-Jacques; Thellièr, Christophe; Peverini, Luca

    2015-01-01

    Piezo bimorph mirrors are versatile active optics used on many synchrotron beamlines. However, many bimorphs suffer from the ‘junction effect’: a periodic deformation of the optical surface which causes major aberrations to the reflected X-ray beam. This effect is linked to the construction of such mirrors, where piezo ceramics are glued directly below the thin optical substrate. In order to address this problem, a next-generation bimorph with piezos bonded to the side faces of a monolithic substrate was developed at Thales-SESO and optimized at Diamond Light Source. Using metrology feedback from the Diamond-NOM, the optical slope error was reduced to ∼0.5 µrad r.m.s. for a range of ellipses. To maximize usability, a novel holder was built to accommodate the substrate in any orientation. When replacing a first-generation bimorph on a synchrotron beamline, the new mirror significantly improved the size and shape of the reflected X-ray beam. Most importantly, there was no evidence of the junction effect even after eight months of continuous beamline usage. It is hoped that this new design will reinvigorate the use of active bimorph optics at synchrotron and free-electron laser facilities to manipulate and correct X-ray wavefronts. PMID:25537582

  15. Symmetry Breaking by Surface Blocking: Synthesis of Bimorphic Silver Nanoparticles, Nanoscale Fishes and Apples

    PubMed Central

    Cathcart, Nicole; Kitaev, Vladimir

    2016-01-01

    A powerful approach to augment the diversity of well-defined metal nanoparticle (MNP) morphologies, essential for MNP advanced applications, is symmetry breaking combined with seeded growth. Utilizing this approach enabled the formation of bimorphic silver nanoparticles (bi-AgNPs) consisting of two shapes linked by one regrowth point. Bi-AgNPs were formed by using an adsorbing polymer, poly(acrylic acid), PAA, to block the surface of a decahedral AgNP seed and restricting growth of new silver to a single nucleation point. First, we have realized 2-D growth of platelets attached to decahedra producing nanoscale shapes reminiscent of apples, fishes, mushrooms and kites. 1-D bimorphic growth of rods (with chloride) and 3-D bimorphic growth of cubes and bipyramids (with bromide) were achieved by using halides to induce preferential (100) stabilization over (111) of platelets. Furthermore, the universality of the formation of bimorphic nanoparticles was demonstrated by using different seeds. Bi-AgNPs exhibit strong SERS enhancement due to regular cavities at the necks. Overall, the reported approach to symmetry breaking and bimorphic nanoparticle growth offers a powerful methodology for nanoscale shape design. PMID:27605125

  16. Characterization of a next-generation piezo bimorph X-ray mirror for synchrotron beamlines.

    PubMed

    Alcock, Simon G; Nistea, Ioana; Sutter, John P; Sawhney, Kawal; Fermé, Jean Jacques; Thellièr, Christophe; Peverini, Luca

    2015-01-01

    Piezo bimorph mirrors are versatile active optics used on many synchrotron beamlines. However, many bimorphs suffer from the `junction effect': a periodic deformation of the optical surface which causes major aberrations to the reflected X-ray beam. This effect is linked to the construction of such mirrors, where piezo ceramics are glued directly below the thin optical substrate. In order to address this problem, a next-generation bimorph with piezos bonded to the side faces of a monolithic substrate was developed at Thales-SESO and optimized at Diamond Light Source. Using metrology feedback from the Diamond-NOM, the optical slope error was reduced to ∼ 0.5 µrad r.m.s. for a range of ellipses. To maximize usability, a novel holder was built to accommodate the substrate in any orientation. When replacing a first-generation bimorph on a synchrotron beamline, the new mirror significantly improved the size and shape of the reflected X-ray beam. Most importantly, there was no evidence of the junction effect even after eight months of continuous beamline usage. It is hoped that this new design will reinvigorate the use of active bimorph optics at synchrotron and free-electron laser facilities to manipulate and correct X-ray wavefronts.

  17. PZT-5A4/PA and PZT-5A4/PDMS piezoelectric composite bimorphs

    NASA Astrophysics Data System (ADS)

    Babu, I.; Hendrix, M. M. R. M.; de With, G.

    2014-02-01

    Disc type reinforced piezoelectric composite bimorphs with series connection were designed and the performance was investigated. The composite bimorphs (PZT/PA and PZT/PDMS (40/60 vol%)) were successfully fabricated by a compression molding and solution casting technique. The charge developed at an applied force of 150 N is 18150 pC (PZT/PA) and 2310 pC (PZT/PDMS), respectively. Electric force microscopy (EFM) is used to study the structural characterization and piezoelectric properties of the materials realized. A clear inverse piezoelectric effect was observed when the bimorphs were subjected to an electric field stepped up through 2, 6 and 10 V, indicating the net polarization direction of the different ferroelectric domains. The as-developed bimorphs have the basic structure of a sensor and actuator, and, since they do not use any bonding agent for bonding, they can provide a valuable alternative to the present bimorphs where bonding processes are required for their realization that can limit their application at high temperature.

  18. Piezoelectric bimorphs' characteristics as in-socket sensors for transfemoral amputees.

    PubMed

    El-Sayed, Amr M; Hamzaid, Nur Azah; Abu Osman, Noor Azuan

    2014-12-10

    Alternative sensory systems for the development of prosthetic knees are being increasingly highlighted nowadays, due to the rapid advancements in the field of lower limb prosthetics. This study presents the use of piezoelectric bimorphs as in-socket sensors for transfemoral amputees. An Instron machine was used in the calibration procedure and the corresponding output data were further analyzed to determine the static and dynamic characteristics of the piezoelectric bimorph. The piezoelectric bimorph showed appropriate static operating range, repeatability, hysteresis, and frequency response for application in lower prosthesis, with a force range of 0-100 N. To further validate this finding, an experiment was conducted with a single transfemoral amputee subject to measure the stump/socket pressure using the piezoelectric bimorph embedded inside the socket. The results showed that a maximum interface pressure of about 27 kPa occurred at the anterior proximal site compared to the anterior distal and posterior sites, consistent with values published in other studies. This paper highlighted the capacity of piezoelectric bimorphs to perform as in-socket sensors for transfemoral amputees. However, further experiments are recommended to be conducted with different amputees with different socket types.

  19. The inverse problem of bimorph mirror tuning on a beamline

    SciTech Connect

    Huang, Rong

    2013-03-07

    One of the challenges of tuning bimorph mirrors with many electrodes is that the calculated focusing voltages can be different by more than the safety limit (such as 500 V for the mirrors used at 17-ID at the Advanced Photon Source) between adjacent electrodes. A study of this problem at 17-ID revealed that the inverse problem of the tuning in situ, using X-rays, became ill-conditioned when the number of electrodes was large and the calculated focusing voltages were contaminated with measurement errors. Increasing the number of beamlets during the tuning could reduce the matrix condition number in the problem, but obtaining voltages with variation below the safety limit was still not always guaranteed and multiple iterations of tuning were often required. Applying Tikhonov regularization and using the L-curve criterion for the determination of the regularization parameter made it straightforward to obtain focusing voltages with well behaved variations. Some characteristics of the tuning results obtained using Tikhonov regularization are given in this paper.

  20. The Development and Optimisation of High Bandwidth Bimorph Deformable Mirrors

    NASA Astrophysics Data System (ADS)

    Rowe, D.; Laycock, L.; Griffith, M.; Archer, N.

    Our first mirror designs were based on a standard bimorph construction and exhibited a resonant frequency of 1 kHz with a maximum stroke of ±5 μm. These devices were limited by the requirement to have a "dead space" between the inner active area and the mirror boundary. This was necessary to ensure that the requirements for both the stroke and the static boundary conditions at the edge of the mirror could be met simultaneously, but there was a significant penalty to pay in terms of bandwidth, which is inversely proportional to the square of the full mirror diameter. In a series of design iteration steps, we have created mounting arrangements that seek not only to reduce dead space, but also to improve ruggedness and temperature stability through the use of a repeatable and reliable assembly procedure. As a result, the most recently modeled mirrors display a resonance in excess of 5 kHz, combined with a maximum stroke in excess of ±10 μm. This has been achieved by virtually eliminating the "dead space" around the mirror. By careful thermal matching of the mirror and piezoelectric substrates, operation over a wide temperature range is possible. This paper will discuss the outcomes from the design study and present our initial experimental results for the most recently assembled mirror.

  1. Electronic transport properties of In-doped ZnO nanobelts with different concentration.

    PubMed

    Su, Jia; Li, Huifeng; Huang, Yunhua; Xing, Xiujun; Zhao, Jing; Zhang, Yue

    2011-05-01

    In this paper, zinc oxide (ZnO) nanobelts with five different indium (In) concentrations (1.98, 2.73, 3.33, 4.20, and 5.16 wt%) were prepared by simple vapor deposition with HAuCl(4) (1% solution) as catalyst. Detailed structural and compositional characterizations were performed by XRD, TEM, EDS, PL, and Raman spectroscopy. Moreover, the current-voltage (I-V) characteristics of In-doped ZnO nanobelts with different In concentrations were determined by nano-manipulation and measurement systems. The results show that the resistivity of these nanobelts decreases with increasing In concentration when the doping concentration of In is lower than 4.20%, but, on the contrary, when the In concentration is higher than 4.20% their resistivity increases. Also, all of the nanobelts keep ohmic contact very well. Simultaneously, the influence of electron beam irradiation (20 kV) on the nanobelts was studied, and it was found that electron beam irradiation can improve the conductivity of the nanobelts. Under the same voltage, the current increased gradually during irradiation until equilibrium was reached. The degree of influence of the irradiation on the resistivity of the nanobelts is the greatest when the In dopant concentration is 4.20%, which is suitable for making irradiation sensors. PMID:21445421

  2. Controllable synthesis of SnO{sub 2} nanowires and nanobelts by Ga catalysts

    SciTech Connect

    Xie Xing; Shao Zhibin; Yang Qianhui; Shen Xiaoshuang; Zhu Wei; Hong Xun; Wang Guanzhong

    2012-07-15

    We report the morphology control of one-dimensional (1D) SnO{sub 2} nanostructures by Ga catalysts using thermal evaporation method. Gallium (Ga), either from decomposition of GaN powder or from Ga metal, is adopted as a catalyst for the growth of long SnO{sub 2} nanowires and nanobelts. At similar experimental conditions, quantities of nanobelts are formed instead of nanowires when the temperature and reaction time are increased. Such approach enables us to synthesize various morphologies of SnO{sub 2} nanobelts with different side facets. Novel nanobelts with [0 0 1] growth direction with high energy side facets are obtained for the first time, which is attributed to the large amount of oxygen vacancies introduced in the nanobelts by the Ga catalysts. - Graphical abstract: Morphology control of one-dimensional SnO{sub 2} nanostructures are realized via a thermal evaporation method. Novel nanobelts along [0 0 1] direction having high energy side facets were fabricated for the first time. Highlights: Black-Right-Pointing-Pointer Morphology control of one-dimensional SnO{sub 2} nanostructures are realized by Ga catalysts using thermal evaporation method. Black-Right-Pointing-Pointer Oxygen vacancies influenced the growth directions in order to neutralize thermodynamic instability. Black-Right-Pointing-Pointer Novel nanobelts with [0 0 1] growth direction with high energy side facets are obtained for the first time.

  3. Tunable growth of silver nanobelts on monolithic activated carbon with size-dependent plasmonic response

    PubMed Central

    Zhao, Hong; Ning, Yuesheng; Zhao, Binyuan; Yin, Fujun; Du, Cuiling; Wang, Fei; Lai, Yijian; Zheng, Junwei; Li, Shuan; Chen, Li

    2015-01-01

    Silver is one of the most important materials in plasmonics. Tuning the size of various silver nanostructures has been actively pursued in the last decade. However, silver nanobelt, a typical one-dimensional silver nanostructure, has not been systematically studied as to tuning its size for controllable plasmonic response. Here we show that silver nanobelts, with mean width ranging from 45 to 105 nm and thickness at ca. 13 nm, can grow abundantly on monolithic activated carbon (MAC) through a galvanic-cell reaction mechanism. The widths of silver nanobelts are positively correlated to the growth temperatures. The width/thickness ratio of the silver nanobelts can be adjusted so that their transversal plasmonic absorption peaks can nearly span the whole visible light band, which endows them with different colours. This work demonstrates the great versatility of a simple, green and conceptually novel approach in controlled synthesis of noble metal nanostructures. PMID:26337008

  4. Hydrothermal synthesis of sodium vanadate nanobelts as high-performance cathode materials for lithium batteries

    NASA Astrophysics Data System (ADS)

    Yang, Kaiwen; Fang, Guozhao; Zhou, Jiang; Qin, Mulan; Tang, Yan; Pan, Anqiang; Liang, Shuquan

    2016-09-01

    The sodium vanadate (Na0.76V6O15) nanobelts have been successfully synthesized via a facile hydrothermal reaction followed by annealing. The ultra-long nanobelts have a length ranging from several micrometers to several dozens of micrometers. As cathode materials for lithium-ion batteries, the Na0.76V6O15 nanobelts exhibit high discharge capacity, excellent cyclic stability and good rate capability. High discharge capacity of 248 and 214 mA h g-1 can be obtained at the current density of 300 and 500 mA g-1, respectively. Meanwhile, it maintains a stable capacity of 113 mA h g-1 after 200 cycles at a high current density of 2000 mA g-1 with no capacity decay. The superior electrochemical performances may be attributed to the novel nanobelts structure and excellent structural stability of Na0.76V6O15.

  5. Y-shaped ZnO Nanobelts Driven from Twinned Dislocations

    PubMed Central

    Shi, Yuan; Bao, Shuhan; Shi, Run; Huang, Chengzi; Amini, Abbas; Wu, Zefei; Zhang, Linfei; Wang, Ning; Cheng, Chun

    2016-01-01

    Y-shaped ZnO nanobelts are fabricated by a simple thermal evaporation method. Transmission Electron Microscopy (TEM) investigation shows that these ZnO nanobelts are crystals with twinned planes {11–21}. Convergent Beam Electron Diffraction studies show that the two sides of twinned nanobelts are O-terminated towards the twinned boundary and Zn-terminated outwards. The two branches of twinned ZnO nanobelts grow along [11–26] from the trunk and then turn to the polarization direction [0001]. The featured Y-shape morphology and TEM characterizations indicate that the growth of these novel nanostructures is driven by an unusual twinned dislocation growth mechanism. PMID:26931057

  6. Ultrathin single-crystal ZnO nanobelts: Ag-catalyzed growth and field emission property

    NASA Astrophysics Data System (ADS)

    Xing, G. Z.; Fang, X. S.; Zhang, Z.; Wang, D. D.; Huang, X.; Guo, J.; Liao, L.; Zheng, Z.; Xu, H. R.; Yu, T.; Shen, Z. X.; Huan, C. H. A.; Sum, T. C.; Zhang, H.; Wu, T.

    2010-06-01

    We report the growth of ultrathin single-crystal ZnO nanobelts by using a Ag-catalyzed vapor transport method. Extensive transmission electron microscopy and atomic force microscopy measurements reveal that the thickness of the ultrathin ZnO nanobelts is ~ 2 nm. Scanning electron microscopy and post-growth annealing studies suggest a '1D branching and 2D filling' growth process. Our results demonstrate the critical role of catalyst in the deterministic synthesis of nanomaterials with the desired morphology. In addition, these ultrafine nanobelts exhibit stable field emission with unprecedented high emission current density of 40.17 mA cm - 2. These bottom-up building blocks of ultrathin ZnO nanobelts may facilitate the construction of advanced electronic and photonic nanodevices.

  7. Tunable growth of silver nanobelts on monolithic activated carbon with size-dependent plasmonic response

    NASA Astrophysics Data System (ADS)

    Zhao, Hong; Ning, Yuesheng; Zhao, Binyuan; Yin, Fujun; Du, Cuiling; Wang, Fei; Lai, Yijian; Zheng, Junwei; Li, Shuan; Chen, Li

    2015-09-01

    Silver is one of the most important materials in plasmonics. Tuning the size of various silver nanostructures has been actively pursued in the last decade. However, silver nanobelt, a typical one-dimensional silver nanostructure, has not been systematically studied as to tuning its size for controllable plasmonic response. Here we show that silver nanobelts, with mean width ranging from 45 to 105 nm and thickness at ca. 13 nm, can grow abundantly on monolithic activated carbon (MAC) through a galvanic-cell reaction mechanism. The widths of silver nanobelts are positively correlated to the growth temperatures. The width/thickness ratio of the silver nanobelts can be adjusted so that their transversal plasmonic absorption peaks can nearly span the whole visible light band, which endows them with different colours. This work demonstrates the great versatility of a simple, green and conceptually novel approach in controlled synthesis of noble metal nanostructures.

  8. Investigation of photoelectrical properties of α-Si3N4 nanobelts with surface modifications using first-principles calculations.

    PubMed

    Xiong, Li; Dai, Jianhong; Song, Yan; Wen, Guangwu; Qin, Chunlin

    2016-06-21

    The structural stability, electronic and optical properties of α-Si3N4 nanobelts orientating along the different directions with surface H, F and Cl modifications are investigated using first-principles methods. The stabilities of α-Si3N4 nanobelts are greatly affected by the surface modifications and increased in the order of H, Cl and F. All the modified α-Si3N4 nanobelts exhibit semiconductor characteristics. The effective masses of nanobelts are mainly affected by their orientations as well as surface modifications. The band gaps of α-Si3N4 nanobelts are found to be modulated by surface modifications. The Cl-modified nanobelts result in a smaller band gap than that of H- or F-modified ones. The electronic properties of α-Si3N4 nanobelts have significantly affected their optical properties. The linear light response ranges are mainly located in the ultraviolet region, where the absorption and refraction of light mainly occur, while the reflection is very weak. As the halogen coverage increases to 100%, the absorption edges of α-Si3N4 nanobelts have an obvious red-shift and new dielectric peaks appear. The Cl-modified nanobelts possess higher ε2(ω) peaks, lower absorption edges and better photoelectric characteristics than those of H- or F-modified nanobelts. The static optical parameters ε(0) and n(0) of 100% Cl-modified α-Si3N4 nanobelts are significantly larger than those of other nanobelts, indicating special applications in certain optical components. PMID:27225041

  9. Temperature Dependence of the Piezotronic and Piezophototronic Effects in a-axis GaN Nanobelts.

    PubMed

    Wang, Xingfu; Yu, Ruomeng; Peng, Wenbo; Wu, Wenzhuo; Li, Shuti; Wang, Zhong Lin

    2015-12-22

    The temperature dependence of the piezotronic and piezophototronic effects in a-axis GaN nanobelts from 77 to 300 K is investigated. The piezotronic effect is enhanced by over 440% under lower temp-eratures. Two independent processes are discovered to form a competing mechanism through the investigation of the temperature dependence of the piezophototronic effect in a-axis GaN nanobelts.

  10. Hexagonal NiS nanobelts as advanced cathode materials for rechargeable Al-ion batteries.

    PubMed

    Yu, Zhijing; Kang, Zepeng; Hu, Zongqian; Lu, Jianhong; Zhou, Zhigang; Jiao, Shuqiang

    2016-08-16

    Hexagonal NiS nanobelts served as novel cathode materials for rechargeable Al-ion batteries based on an AlCl3/[EMIm]Cl ionic liquid electrolyte system. The nano-banded structure of the materials can facilitate the electrolyte immersion and enhance Al(3+) diffusion. The hexagonal NiS nanobelt based cathodes exhibit high storage capacity, good cyclability and low overpotential. PMID:27487940

  11. Synthesis of CaCO3 Nanobelts for Drug Delivery in Cancer Therapy.

    PubMed

    Sun, Dongmei; Peng, Haibao; Wang, Shilong; Zhu, Dazhang

    2015-12-01

    Nanobelt carriers have demonstrated some advantages such as good biocompatibility, biodegradability, and strain-accommodating properties. We prepared an optimized nanobelt carrier formulation for drug (etoposide) as an oral delivery system and estimated the potential of calcium carbonate (CaCO3) nanobelts. The nanobelts were prepared by the method of binary solvent approach and were characterized by transmission electron microscope (TEM), scanning electron microscopy (SEM), and ultraviolet-visible (UV-vis) spectra. MTT (3-(4,5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide) assay test exhibited that etoposide-loaded calcium carbonate nanobelts (ECCNBs) showed a higher cell kill ratio against SGC-7901 cells compared with free drug. The apoptosis test and cell cycle test analysis revealed that etoposide entrapped in calcium carbonate nanobelts (CCNBs) could enhance the delivery efficiencies of drug and improved inhibition effect. The present findings demonstrated that ECCNBs might induce cell cycle arrest at G2/M phase and cell apoptosis in a p53-related manner. It can be foreseen that CCNBs are a promising drug carrier to store the anti-cancer drug for cancer therapy and drug delivery. PMID:26055480

  12. Electrical and optoelectrical modification of cadmium sulfide nanobelts by low-energy electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Zhang, Lijie; Liu, Manman; Zhao, Mei; Dong, Youqing; Zou, Chao; Yang, Keqin; Yang, Yun; Huang, Shaoming; Zhu, Da-Ming

    2016-09-01

    In this report, we describe a method for modifying electrical and optoelectrical properties of CdS nanobelts using low-energy (lower than 10 keV) e-beam irradiation in a scanning electron microscope. The electrical conductivity of the nanobelts was dramatically improved via the irradiation of e-beams. The modified conductivity of the nanobelts depends on the energy of the e-beam; it exhibits a larger photocurrent and higher external quantum efficiency but slower time-response than that before the modification. A possible mechanism about the modification is the increase of electron accumulation (injected electrons) in the nanobelts due to e-beam irradiation. In addition, the optoelectrical modification could be caused by the trapped electrons in the nanobelts and the decrease of contact resistance between the nanobelts and metal electrodes induced by e-beam irradiation. The results of this work are significant for the in situ study of semiconductor nanostructures in the electron microscope. Besides, the method of electrical and optoelectrical modification presented here has potential application in electronics and optoelectronics.

  13. Synthesis of CaCO3 Nanobelts for Drug Delivery in Cancer Therapy

    NASA Astrophysics Data System (ADS)

    Sun, Dongmei; Peng, Haibao; Wang, Shilong; Zhu, Dazhang

    2015-05-01

    Nanobelt carriers have demonstrated some advantages such as good biocompatibility, biodegradability, and strain-accommodating properties. We prepared an optimized nanobelt carrier formulation for drug (etoposide) as an oral delivery system and estimated the potential of calcium carbonate (CaCO3) nanobelts. The nanobelts were prepared by the method of binary solvent approach and were characterized by transmission electron microscope (TEM), scanning electron microscopy (SEM), and ultraviolet-visible (UV-vis) spectra. MTT (3-(4,5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide) assay test exhibited that etoposide-loaded calcium carbonate nanobelts (ECCNBs) showed a higher cell kill ratio against SGC-7901 cells compared with free drug. The apoptosis test and cell cycle test analysis revealed that etoposide entrapped in calcium carbonate nanobelts (CCNBs) could enhance the delivery efficiencies of drug and improved inhibition effect. The present findings demonstrated that ECCNBs might induce cell cycle arrest at G2/M phase and cell apoptosis in a p53-related manner. It can be foreseen that CCNBs are a promising drug carrier to store the anti-cancer drug for cancer therapy and drug delivery.

  14. Electrical and optoelectrical modification of cadmium sulfide nanobelts by low-energy electron beam irradiation.

    PubMed

    Zhang, Lijie; Liu, Manman; Zhao, Mei; Dong, Youqing; Zou, Chao; Yang, Keqin; Yang, Yun; Huang, Shaoming; Zhu, Da-Ming

    2016-09-30

    In this report, we describe a method for modifying electrical and optoelectrical properties of CdS nanobelts using low-energy (lower than 10 keV) e-beam irradiation in a scanning electron microscope. The electrical conductivity of the nanobelts was dramatically improved via the irradiation of e-beams. The modified conductivity of the nanobelts depends on the energy of the e-beam; it exhibits a larger photocurrent and higher external quantum efficiency but slower time-response than that before the modification. A possible mechanism about the modification is the increase of electron accumulation (injected electrons) in the nanobelts due to e-beam irradiation. In addition, the optoelectrical modification could be caused by the trapped electrons in the nanobelts and the decrease of contact resistance between the nanobelts and metal electrodes induced by e-beam irradiation. The results of this work are significant for the in situ study of semiconductor nanostructures in the electron microscope. Besides, the method of electrical and optoelectrical modification presented here has potential application in electronics and optoelectronics. PMID:27561004

  15. Direct laser pruning of CdS(x)Se1-x nanobelts en route to a multicolored pattern with controlled functionalities.

    PubMed

    Lu, Junpeng; Lim, Xiaodai; Zheng, Minrui; Mhaisalkar, Subodh G; Sow, Chorng-Haur

    2012-09-25

    CdS(x)Se(1-x) nanobelts are interesting nanostructured materials with a tunable band gap from 1.7 to 2.4 eV depending on the nanobelts' stoichiometry. On the basis of their chemical compositions, these nanobelts give out strong photoluminescence with unique color. In this work, we demonstrate that a direct focused laser beam irradiation was able to achieve localized modification of the chemical composition of the nanobelts. As a result, we could locally change the optical properties of these nanobelts. With a scanning laser beam, micropatterns with a wide range of fluorescence color could be created on a substrate covered with ternary nanobelts without a prepatterned mask. The laser modified nanobelts showed higher resistance to acid corrosion and these nanobelts exhibited more superior photoconductivity. The construction of micropatterns with functionality/color control within the sample would provide greater building blocks for photoelectronic applications.

  16. A finger-like hardness tester based on the contact electromechanical impedance of a piezoelectric bimorph cantilever

    NASA Astrophysics Data System (ADS)

    Fu, Ji; Li, Faxin

    2015-10-01

    We proposed a finger-like hardness tester based on the electromechanical impedance of a piezoelectric bimorph cantilever. A Vickers indenter was fabricated to the free end of the bimorph to contact the sample. The contact force was monitored by a strain gauge and the contact area was obtained by tracking the bimorph's resonance frequency. The bimorph-sample contact system was modeled by the electromechanical equivalent circuit method. Verification experiments on standard hardness samples were conducted and the measured hardness values agreed well with those given by a conventional Vickers hardness tester. Further hardness measurement on a gear wheel showed that the proposed hardness tester is very adaptive and can be used for inner surface testing or in situ testing, where other hardness testers may not be applicable. The proposed hardness tester can be regarded as an improved ultrasonic hardness tester.

  17. Modeling of the Through-the-Thickness Electric Potentials of a Piezoelectric Bimorph Using the Spectral Element Method

    PubMed Central

    Dong, Xingjian; Peng, Zhike; Hua, Hongxing; Meng, Guang

    2014-01-01

    An efficient spectral element (SE) with electric potential degrees of freedom (DOF) is proposed to investigate the static electromechanical responses of a piezoelectric bimorph for its actuator and sensor functions. A sublayer model based on the piecewise linear approximation for the electric potential is used to describe the nonlinear distribution of electric potential through the thickness of the piezoelectric layers. An equivalent single layer (ESL) model based on first-order shear deformation theory (FSDT) is used to describe the displacement field. The Legendre orthogonal polynomials of order 5 are used in the element interpolation functions. The validity and the capability of the present SE model for investigation of global and local responses of the piezoelectric bimorph are confirmed by comparing the present solutions with those obtained from coupled 3-D finite element (FE) analysis. It is shown that, without introducing any higher-order electric potential assumptions, the current method can accurately describe the distribution of the electric potential across the thickness even for a rather thick bimorph. It is revealed that the effect of electric potential is significant when the bimorph is used as sensor while the effect is insignificant when the bimorph is used as actuator, and therefore, the present study may provide a better understanding of the nonlinear induced electric potential for bimorph sensor and actuator. PMID:24561399

  18. Fast optimization of a bimorph mirror using x-ray grating interferometry.

    PubMed

    Wang, Hongchang; Sawhney, Kawal; Berujon, Sebastien; Sutter, John; Alcock, Simon G; Wagner, Ulrich; Rau, Christoph

    2014-04-15

    An x-ray grating interferometer was employed for in situ optimization of an x-ray bimorph mirror. Unlike many other at-wavelength techniques, only a single interferogram image, captured out of the focal plane, is required, enabling the optical surface to be quickly optimized. Moiré fringe analysis was used to calculate the wavefront slope error, which is proportional to the mirror's slope error. Using feedback from grating interferometry, the slope error of a bimorph mirror was reduced to <200  nrad (rms) in only two iterations. This technique has the potential to create photon beams with spatially homogeneous intensities for use in synchrotron and free electron laser beam lines.

  19. Design of a Compact, Bimorph Deformable Mirror-Based Adaptive Optics Scanning Laser Ophthalmoscope.

    PubMed

    He, Yi; Deng, Guohua; Wei, Ling; Li, Xiqi; Yang, Jinsheng; Shi, Guohua; Zhang, Yudong

    2016-01-01

    We have designed, constructed and tested an adaptive optics scanning laser ophthalmoscope (AOSLO) using a bimorph mirror. The simulated AOSLO system achieves diffraction-limited criterion through all the raster scanning fields (6.4 mm pupil, 3° × 3° on pupil). The bimorph mirror-based AOSLO corrected ocular aberrations in model eyes to less than 0.1 μm RMS wavefront error with a closed-loop bandwidth of a few Hz. Facilitated with a bimorph mirror at a stroke of ±15 μm with 35 elements and an aperture of 20 mm, the new AOSLO system has a size only half that of the first-generation AOSLO system. The significant increase in stroke allows for large ocular aberrations such as defocus in the range of ±600° and astigmatism in the range of ±200°, thereby fully exploiting the AO correcting capabilities for diseased human eyes in the future.

  20. Design of a Compact, Bimorph Deformable Mirror-Based Adaptive Optics Scanning Laser Ophthalmoscope.

    PubMed

    He, Yi; Deng, Guohua; Wei, Ling; Li, Xiqi; Yang, Jinsheng; Shi, Guohua; Zhang, Yudong

    2016-01-01

    We have designed, constructed and tested an adaptive optics scanning laser ophthalmoscope (AOSLO) using a bimorph mirror. The simulated AOSLO system achieves diffraction-limited criterion through all the raster scanning fields (6.4 mm pupil, 3° × 3° on pupil). The bimorph mirror-based AOSLO corrected ocular aberrations in model eyes to less than 0.1 μm RMS wavefront error with a closed-loop bandwidth of a few Hz. Facilitated with a bimorph mirror at a stroke of ±15 μm with 35 elements and an aperture of 20 mm, the new AOSLO system has a size only half that of the first-generation AOSLO system. The significant increase in stroke allows for large ocular aberrations such as defocus in the range of ±600° and astigmatism in the range of ±200°, thereby fully exploiting the AO correcting capabilities for diseased human eyes in the future. PMID:27526166

  1. Bimorph Silk Microsheets with Programmable Actuating Behavior: Experimental Analysis and Computer Simulations.

    PubMed

    Ye, Chunhong; Nikolov, Svetoslav V; Geryak, Ren D; Calabrese, Rossella; Ankner, John F; Alexeev, Alexander; Kaplan, David L; Tsukruk, Vladimir V

    2016-07-13

    Microscaled self-rolling construct sheets from silk protein material have been fabricated, containing a silk bimorph composed of silk ionomers as an active layer and cross-linked silk β-sheet as the passive layer. The programmable morphology was experimentally explored along with a computational simulation to understand the mechanism of shape reconfiguration. The neutron reflectivity shows that the active silk ionomers layer undergoes remarkable swelling (eight times increase in thickness) after deprotonation while the passive silk β-sheet retains constant volume under the same conditions and supports the bimorph construct. This selective swelling within the silk-on-silk bimorph microsheets generates strong interfacial stress between layers and out-of-plane forces, which trigger autonomous self-rolling into various 3D constructs such as cylindrical and helical tubules. The experimental observations and computational modeling confirmed the role of interfacial stresses and allow programming the morphology of the 3D constructs with particular design. We demonstrated that the biaxial stress distribution over the 2D planar films depends upon the lateral dimensions, thickness and the aspect ratio of the microsheets. The results allow the fine-tuning of autonomous shape transformations for the further design of complex micro-origami constructs and the silk based rolling/unrolling structures provide a promising platform for polymer-based biomimetic devices for implant applications. PMID:27308946

  2. Design and fabrication of bimorph transducer for optimal vibration energy harvesting.

    PubMed

    Bedekar, Vishwas; Oliver, Josiah; Priya, Shashank

    2010-07-01

    High energy density piezoelectric composition corresponding to 0.9Pb(Zr0.56Ti0.44)O3–0.1Pb[(Zn0.8/3Ni0.2/3) Nb2/3]O3 + 2 mol% MnO2 (PZTZNN) and 0.8[Pb(Zr0.52Ti0.48) O3]-0.2[Pb(Zn1/3Nb2/3)O3] (PZTPZN) were synthesized by conventional ceramic processing technique using three different sintering profiles. Plates of the sintered samples were used to fabricate the piezoelectric bimorphs with optimized dimensions to exhibit resonance in the loaded condition in the range of ~200 Hz. An analytical model for energy harvesting from bimorph transducer was developed which was confirmed by experimental measurements. The results of this study clearly show that power density of bimorph transducer can be enhanced by increasing the magnitude of product (d ∙ g), where d is the piezoelectric strain constant and g is the piezoelectric voltage constant. PMID:20941885

  3. AlN-based piezoelectric bimorph microgenerator utilizing low-level non-resonant excitation

    NASA Astrophysics Data System (ADS)

    Hampl, Stefan; Cimalla, Volker; Polster, Tobias; Hoffmann, Martin

    2011-06-01

    This work aims for utilizing human ocular motion for the self-sufficient power supply of a minimally invasive implantable monitoring system for intraocular pressure (IOP). With a proven piezoelectric functionality (d33>5 pm/V), nanocrystalline thin films of aluminum nitride (AlN) provide a good capability for micromechanical energy harvesting (EH) in medical applications. Many d31-mode microcantilever architectures are poorly suited for human-induced EH: Resonant mass-spring-damper systems are tested under high, narrow-band excitation frequencies. However, human motions, e.g. vibrations of eyeballs are marked by their low frequency, unpredictable, mainly aperiodic and time-varying signature. Different vibration types and directions are 3-dimensionally superimposed. Saccadic eye movements are favorable for inertial microgenerators because of their high dynamic loading (ω<=1000°/s). Our generator concept (symmetric active/active-parallel-bimorph cantilever) enables a high structural compliance by maximizing the piezoactive volume at very low cantilever thicknesses (<1 μm). An increased length and seismic mass enable an effective excitation by low-level aperiodic vibrations such as saccadic acceleration impulses. Analytic calculations and FEA-simulations investigate the potential distribution and transient response of different bimorph structures (length 200- 1000 μm, width 20-200 μm) on broadband vibrations. First released monomorph and bimorph structures show very low resonant frequencies and an adequate robustness.

  4. Structure and resistivity of bismuth nanobelts in situ synthesized on silicon wafer through an ethanol-thermal method

    NASA Astrophysics Data System (ADS)

    Gao, Zheng; Qin, Haiming; Yan, Tao; Liu, Hong; Wang, Jiyang

    2011-12-01

    Bismuth nanobelts in situ grown on a silicon wafer were synthesized through an ethanol-thermal method without any capping agent. The structure of the bismuth belt-silicon composite nanostructure was characterized by scanning electron microscope, energy-dispersive X-ray spectroscopy, and high resolution transmission electron microscope. The nanobelt is a multilayered structure 100-800 nm in width and over 50 μm in length. One layer has a thickness of about 50 nm. A unique sword-like nanostructure is observed as the initial structure of the nanobelts. From these observations, a possible growth mechanism of the nanobelt is proposed. Current-voltage property measurements indicate that the resistivity of the nanobelts is slightly larger than that of the bulk bismuth material.

  5. One-dimensional copper hydroxide nitrate nanorods and nanobelts for radiochemical applications.

    PubMed

    Liu, Bin

    2012-11-21

    I report a facile wet-chemical method for the synthesis of one-dimensional copper hydroxide nitrate nanostructures in 2-propanol under solvothermal conditions. Single-crystalline nearly monodispersed copper hydroxide nitrate nanorods and nanobelts with selected breadths in the range of 100 nm to 1 μm have been successfully prepared by a solvothermal method through controlling the experimental parameters, including initial concentrations of reagents, reaction temperature, solvent and reaction time. The resultant nanorods and nanobelts were characterized using FESEM, TEM, XRD, FTIR and TGA techniques. Upon thermal calcination, the copper hydroxide nitrate nanorods and nanobelts self-assemble into one-dimensional arrays (rods, belts or tubes) of copper oxide nanoparticles. The as-prepared copper hydroxide nitrate nanorods and nanobelts were tested as ion exchangers for removal of long-lived radioactive anions such as (129)I(-) and (99)TcO(4)(-). The copper hydroxide nitrate nanorods or nanobelts were over two times more active in the removal of anion species than copper hydroxide nitrate nanoplatelets. PMID:23070067

  6. Deep-ultraviolet solar-blind photoconductivity of individual gallium oxide nanobelts.

    PubMed

    Li, Liang; Auer, Erwin; Liao, Meiyong; Fang, Xiaosheng; Zhai, Tianyou; Gautam, Ujjal K; Lugstein, Alois; Koide, Yasuo; Bando, Yoshio; Golberg, Dmitri

    2011-03-01

    We designed solar-blind deep-ultraviolet semiconductor photodetectors using individual Ga2O3 nanobelts. The photoconductive behavior was systematically studied. The photodetectors demonstrate high selectivity towards 250 nm light, fast response times of less than 0.3 s, and a large photocurrent to dark current ratio of up to 4 orders of magnitude. The photoresponse parameters such as photocurrent, response time, and quantum efficiency depend strongly on the intensity of light, the detector environment, and the nanobelt size. The photoresponse mechanism was discussed, which was mainly attributed to the band bending, surface traps, and distribution of traps in the bandgap. Present Ga2O3 nanobelts can be exploited for future applications in photo sensing, light-emitting diodes, and optical switches.

  7. A wearable, highly stable, strain and bending sensor based on high aspect ratio graphite nanobelts

    NASA Astrophysics Data System (ADS)

    Alaferdov, A. V.; Savu, R.; Rackauskas, T. A.; Rackauskas, S.; Canesqui, M. A.; de Lara, D. S.; Setti, G. O.; Joanni, E.; de Trindade, G. M.; Lima, U. B.; de Souza, A. S.; Moshkalev, S. A.

    2016-09-01

    A simple and scalable method was developed for the fabrication of wearable strain and bending sensors, based on high aspect ratio (length/thickness ˜103) graphite nanobelt thin films deposited by a modified Langmuir-Blodgett technique onto flexible polymer substrates. The sensing mechanism is based on the changes in contact resistance between individual nanobelts upon substrate deformation. Very high sensor response stability for more than 5000 strain-release cycles and a device power consumption as low as 1 nW were achieved. The device maximum stretchability is limited by the metal electrodes and the polymer substrate; the maximum strain that could be applied to the polymer used in this work was 40%. Bending tests carried out for various radii of curvature demonstrated distinct sensor responses for positive and negative curvatures. The graphite nanobelt thin flexible films were successfully tested for acoustic vibration and heartbeat sensing.

  8. A wearable, highly stable, strain and bending sensor based on high aspect ratio graphite nanobelts.

    PubMed

    Alaferdov, A V; Savu, R; Rackauskas, T A; Rackauskas, S; Canesqui, M A; de Lara, D S; Setti, G O; Joanni, E; de Trindade, G M; Lima, U B; de Souza, A S; Moshkalev, S A

    2016-09-16

    A simple and scalable method was developed for the fabrication of wearable strain and bending sensors, based on high aspect ratio (length/thickness ∼10(3)) graphite nanobelt thin films deposited by a modified Langmuir-Blodgett technique onto flexible polymer substrates. The sensing mechanism is based on the changes in contact resistance between individual nanobelts upon substrate deformation. Very high sensor response stability for more than 5000 strain-release cycles and a device power consumption as low as 1 nW were achieved. The device maximum stretchability is limited by the metal electrodes and the polymer substrate; the maximum strain that could be applied to the polymer used in this work was 40%. Bending tests carried out for various radii of curvature demonstrated distinct sensor responses for positive and negative curvatures. The graphite nanobelt thin flexible films were successfully tested for acoustic vibration and heartbeat sensing.

  9. A wearable, highly stable, strain and bending sensor based on high aspect ratio graphite nanobelts.

    PubMed

    Alaferdov, A V; Savu, R; Rackauskas, T A; Rackauskas, S; Canesqui, M A; de Lara, D S; Setti, G O; Joanni, E; de Trindade, G M; Lima, U B; de Souza, A S; Moshkalev, S A

    2016-09-16

    A simple and scalable method was developed for the fabrication of wearable strain and bending sensors, based on high aspect ratio (length/thickness ∼10(3)) graphite nanobelt thin films deposited by a modified Langmuir-Blodgett technique onto flexible polymer substrates. The sensing mechanism is based on the changes in contact resistance between individual nanobelts upon substrate deformation. Very high sensor response stability for more than 5000 strain-release cycles and a device power consumption as low as 1 nW were achieved. The device maximum stretchability is limited by the metal electrodes and the polymer substrate; the maximum strain that could be applied to the polymer used in this work was 40%. Bending tests carried out for various radii of curvature demonstrated distinct sensor responses for positive and negative curvatures. The graphite nanobelt thin flexible films were successfully tested for acoustic vibration and heartbeat sensing. PMID:27486955

  10. Ethanol assisted synthesis of anatase nanobelts with improved crystallinity and photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Ni, Binbin; Li, Feng; Li, Xiaoning; Fu, Zhengping; Zhu, Yanwu; Lu, Yalin

    2013-10-01

    A modified alkaline hydrothermal method via adding the ethanol treatment to the intermediates was developed to synthesize TiO2 nanobelts, in which the main phase is anatase. Compared with the previous reported TiO2 nanobelts obtained without the ethanol treatment, the new TiO2 nanobelts obtained through the ethanol assisted route are with much improved anatase crystallinity and a sharply reduced amount of TiO2-B phase, as well as a significantly higher photocatalytic activity that is even better than P25 for degrading Rhodamine-B under the ultraviolet light irradiation, which apparently correlates to the increased contents and crystallinity of anatase. The mechanism of ethanol treatment is also discussed based on the FTIR results.

  11. A wearable, highly stable, strain and bending sensor based on high aspect ratio graphite nanobelts

    NASA Astrophysics Data System (ADS)

    Alaferdov, A. V.; Savu, R.; Rackauskas, T. A.; Rackauskas, S.; Canesqui, M. A.; de Lara, D. S.; Setti, G. O.; Joanni, E.; de Trindade, G. M.; Lima, U. B.; de Souza, A. S.; Moshkalev, S. A.

    2016-09-01

    A simple and scalable method was developed for the fabrication of wearable strain and bending sensors, based on high aspect ratio (length/thickness ∼103) graphite nanobelt thin films deposited by a modified Langmuir–Blodgett technique onto flexible polymer substrates. The sensing mechanism is based on the changes in contact resistance between individual nanobelts upon substrate deformation. Very high sensor response stability for more than 5000 strain–release cycles and a device power consumption as low as 1 nW were achieved. The device maximum stretchability is limited by the metal electrodes and the polymer substrate; the maximum strain that could be applied to the polymer used in this work was 40%. Bending tests carried out for various radii of curvature demonstrated distinct sensor responses for positive and negative curvatures. The graphite nanobelt thin flexible films were successfully tested for acoustic vibration and heartbeat sensing.

  12. Synthesis and characterization of α-MoO{sub 3} nanobelt composite positive electrode materials for lithium battery application

    SciTech Connect

    Nadimicherla, Reddeppa; Chen, Wen; Guo, Xin

    2015-06-15

    Graphical abstract: (a) TEM image of MoO{sub 3}/PEO nanobelts composite, (b) CV curves of MoO{sub 3}/PEO nanobelts composite. - Highlights: • α-MoO{sub 3} and PEO surfactant MoO{sub 3} nanobelts were synthesized by solvothermal method. • The capacity retention of 12.5 wt% PEO surfactant MoO{sub 3} nanobelts is 88.78%. • The specific capacity of 12.5 wt% PEO surfactant MoO{sub 3} nanobelts is 352 mAh g{sup −1}. • MoO{sub 3}/PEO nanobelts composite material demonstrates good cycling stability as cathode. - Abstract: α-MoO{sub 3} and PEO surfactant MoO{sub 3} nanobelts were synthesized by a solvothermal method. The morphology and nanostructure of samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Bare α-MoO{sub 3} and 12.5 wt% PEO surfactant MoO{sub 3} nanobelts have an initial specific capacities of 279 and 352 mAh g{sup −1}, respectively, at constant current density 30 mA g{sup −1} with potential range of 1.5–4.0 V vs. Li/Li{sup +}. While MoO{sub 3} is modified by the intercalation of PEO, it is effectively shielded against electrostatic interaction between the MoO{sub 3} interlayer and Li{sup +} ions. We reported positive material, a nanocomposite of MoO{sub 3} coated with polyethylene oxide. It presents good cycling stability due to existence of the conductive and protective polyethylene oxide coating and the nanobelt morphology of MoO{sub 3}. The polyethylene oxide acts as a conducting matrix, a binder and an active material, as well as a volume change buffer agent, which holds the MoO{sub 3} particles in place during the discharge cycles. The cyclic voltammograms of the 12.5 wt% PEO surfactant MoO{sub 3} nanobelt composite displayed better cyclic performance compared with pure MoO{sub 3} nanobelts. The specific capacity of the pure MoO{sub 3} nanobelts and 12.5 wt% PEO surfactant MoO{sub 3

  13. Reverse saturable absorption and nonlinear refraction of ultrathin ZrS3 nanobelts

    NASA Astrophysics Data System (ADS)

    Wu, Jia-Jing; Tao, You-Rong; Wang, Jia-Nan; Wu, Zhong-Yu; Fan, Lei; Wu, Xing-Cai

    2016-05-01

    The nonlinear optical (NLO) properties of a ZrS3 nanobelt were measured with a 6.5 ns pulse laser at 532 nm. Its optical response to the incident light exhibits good optical absorptive and refractive effects, with the nonlinear absorption coefficient β = 4.42 × 10-10 m W-1 and the nonlinear refraction coefficient γ = 5.86 × 10-17 m2 W-1 for the ZrS3 nanobelt in ethanol dispersions at an input energy of 34.25 μJ. In addition, the β values and γ values have dependence on input energy. Results show that the ZrS3 nanobelts have an excellent reverse saturable absorption (RSA) performance in nanosecond pulses, demonstrating that ZrS3 nanobelts are an extraordinarily promising novel optical power limiting material. Meanwhile, compared to the pure ZrS3, graphene oxide (GO) and reduced graphene oxide (RGO), composites (ZrS3/GRO) exhibit an enhanced nonlinear absorption response at the same input energy.The nonlinear optical (NLO) properties of a ZrS3 nanobelt were measured with a 6.5 ns pulse laser at 532 nm. Its optical response to the incident light exhibits good optical absorptive and refractive effects, with the nonlinear absorption coefficient β = 4.42 × 10-10 m W-1 and the nonlinear refraction coefficient γ = 5.86 × 10-17 m2 W-1 for the ZrS3 nanobelt in ethanol dispersions at an input energy of 34.25 μJ. In addition, the β values and γ values have dependence on input energy. Results show that the ZrS3 nanobelts have an excellent reverse saturable absorption (RSA) performance in nanosecond pulses, demonstrating that ZrS3 nanobelts are an extraordinarily promising novel optical power limiting material. Meanwhile, compared to the pure ZrS3, graphene oxide (GO) and reduced graphene oxide (RGO), composites (ZrS3/GRO) exhibit an enhanced nonlinear absorption response at the same input energy. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr09268j

  14. Synthesis, structure and electrochemical properties of polyaniline/MoO{sub 3} nanobelt composite for lithium battery

    SciTech Connect

    Mohan, Varishetty Madhu; Chen, Wen; Murakami, Kenji

    2013-02-15

    Graphical abstract: Hydrothermal method was introduced for the synthesis of MoO{sub 3} nanobelts and polyaniline (PANI)/MoO{sub 3} nanobelt composites. The structure and morphology of the samples were studied by X-ray diffraction (XRD), Fourier transform infrared radiation (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. We can see the presence of polyaniline on the MoO{sub 3} nanobelts surface in the TEM pictures as shown in Fig. (a). The pure MoO{sub 3} nanobelts exhibit the initial specific capacity 276 mAhg{sup −1}, whereas PANI/MoO{sub 3} nanobelt composite shows little low initially 228 mAhg{sup −1} after that it has more stabilized specific capacity with increasing cycle numbers as shown in Fig. (b). The cyclic voltammograms of the PANI/MoO{sub 3} nanobelt composite show better cyclic performance compared to pure MoO{sub 3} nanobelts. The electrochemical impedance spectres were studied for both the pure and PANI/MoO{sub 3} samples at 2.0 and 3.5 potentials. The role of the PANI polymeric component of the composite material seems to be the stabilization of the specific capacity due to probable homogeneous distribution of the induced stress during cycling. Display Omitted Highlights: ► Hydrothermal synthesis of MoO{sub 3}, PANI/MoO{sub 3} nanobelts. ► Samples were characterised by XRD, FTIR, DSC, SEM, TEM, CV and impedance. ► MoO{sub 3} nanobelts cathode battery shows initial specific capacity 276 mAhg{sup −1}. ► PANI/MoO{sub 3} nanobelts show initial specific capacity 228 mAhg{sup −1} but high stability. ► PANI/MoO{sub 3} sample studies by impedance at the potentials of 2.0 and 3.5 V. -- Abstract: The MoO{sub 3} nanobelts and polyaniline (PANI)/MoO{sub 3} nanobelt composite were synthesized using hydrothermal method. The crystal structure and morphology of the samples were studied by X-ray diffraction (XRD), Fourier transform infrared radiation (FTIR), scanning electron microscopy (SEM) and

  15. A coordination polymer nanobelt (CPNB)-based aptasensor for sulfadimethoxine.

    PubMed

    Song, Kyung-Mi; Jeong, Euiyoung; Jeon, Weejeong; Jo, Hunho; Ban, Changill

    2012-03-15

    A polymer-based aptasensor, which consisted of fluorescein amidite (FAM)-modified aptamers and coordination polymer nanobelts (CPNBs), was developed utilizing the fluorescence quenching effect to detect sulfadimethoxine residue in food products. A single-stranded DNA (ssDNA) aptamer, which was a specific bio-probe for sulfadimethoxine (Su13; 5'-GAGGGCAACGAGTGTTTATAGA-3'), was discovered by a magnetic bead-based systematic evolution of ligands by exponential enrichment (SELEX) technique, and the fluorescent quenchers CPNBs were produced by mixing AgNO(3) and 4,4'-bipyridine. This aptasensor easily and sensitively detected sulfadimethoxine in solution with a limit of detection (LOD) of 10ng/mL. Furthermore, the antibiotic dissolved in milk was also effectively detected with the same LOD value. In addition, this aptamer probe offered high specificity for sulfadimethoxine compared to other antibiotics. These valuable results provide ample evidence that the CPNB-based aptasensor can be used to quantify sulfadimethoxine residue in food products. PMID:22244734

  16. Growth of zinc oxide nanorods, tetrapods, and nanobelts without catalyst.

    PubMed

    Fouad, O A

    2006-07-01

    Zinc oxide (ZnO) nanostructures with various morphologies have been synthesized without catalyst in a one-step simple redox process. The results show that ZnO nanorods, nanobelts, and tetrapods with hexagonal needled arms could be synthesized via thermal treatment of a mixture of zinc oxide and charcoal powder in a muffle furnace at 1000-1200 degrees C for 240 min. XRD analyses showed that polycrystalline ZnO phase with wurtzite crystal structure was formed. At a relatively low temperature, 1000 degrees C, the ZnO structure was found to be a bundle of denser nanorods. By increasing the reaction temperature to 1100 degrees C, tetrapod-like structures of needle-like arms with pyramidal tips were formed. With the increase of temperature up to 1200 degrees C, the morphology of ZnO nanostructures changed from nanorods and tetrapods to coalescence grains. Reaction temperature was found to be the most important experimental parameter that played an important role in controlling the mode, mechanism of growth, and formation of different ZnO morphologies. PMID:17025131

  17. Photocatalytic degradation of methyl orange over nitrogen-fluorine codoped TiO2 nanobelts prepared by solvothermal synthesis.

    PubMed

    He, Zuoli; Que, Wenxiu; Chen, Jing; Yin, Xingtian; He, Yucheng; Ren, Jiangbo

    2012-12-01

    Anatase type nitrogen-fluorine (N-F) codoped TiO(2) nanobelts were prepared by a solvothermal method in which amorphous titania microspheres were used as the precursors. The as-prepared TiO(2) nanobelts are composed of thin narrow nanobelts and it is noted that there are large amount of wormhole-like mesopores on these narrow nanobelts. Photocatalytic activity of the N-F codoped TiO(2) nanobelts was measured by the reaction of photocatalytic degradation of methyl orange. Results indicate that the photocatalytic activity of the N-F codoped TiO(2) nanobelts is higher than that of P25, which is mainly ascribed to wormhole-like mesopores like prison, larger surface area, and enhanced absorption of light due to N-F codoping. Interestingly, it is also found that the photocatalytic activity can be further enhanced when tested in a new testing method because more photons can be captured by the nanobelts to stimulate the formation of the hole-electron pair.

  18. Structure and resistivity of bismuth nanobelts in situ synthesized on silicon wafer through an ethanol-thermal method

    SciTech Connect

    Gao Zheng; Qin Haiming; Yan Tao

    2011-12-15

    Bismuth nanobelts in situ grown on a silicon wafer were synthesized through an ethanol-thermal method without any capping agent. The structure of the bismuth belt-silicon composite nanostructure was characterized by scanning electron microscope, energy-dispersive X-ray spectroscopy, and high resolution transmission electron microscope. The nanobelt is a multilayered structure 100-800 nm in width and over 50 {mu}m in length. One layer has a thickness of about 50 nm. A unique sword-like nanostructure is observed as the initial structure of the nanobelts. From these observations, a possible growth mechanism of the nanobelt is proposed. Current-voltage property measurements indicate that the resistivity of the nanobelts is slightly larger than that of the bulk bismuth material. - Graphical Abstract: TEM images, EDS, and electron diffraction pattern of bismuth nanobelts. Highlights: Black-Right-Pointing-Pointer Bismuth nanobelts in situ grown on silicon wafer were achieved. Black-Right-Pointing-Pointer Special bismuth-silicon nanostructure. Black-Right-Pointing-Pointer Potential application in sensitive magnetic sensor and other electronic devices.

  19. First-principles studies on transport properties and contact effects of Cu(111)/ZnO-nanobelt(1010)/Cu(111) systems.

    PubMed

    Sun, Xu; Gu, Yousong; Wang, Xueqiang; Zhang, Yue

    2013-08-21

    The transport properties of ZnO nanobelts along the (101¯0) non-polarized direction coupled with Cu electrodes were studied via non-equivalent Greens functions method and density functional theory formalism. The transport properties were greatly affected by interfacial spacing and nanobelt widths. The conductance decreased exponentially with the widths of the nanobelts. Ohmic behavior was found in narrow nanobelts, while rectifying characteristics were observed in wide nanobelts. In the case of narrow belts, the current-voltage characteristics were changed from ohmic type to rectifying characteristics as the interspace increased, corresponding to the contacts transforming from chemical to physical interactions. However, the conductance in the wider nanobelts declined exponentially as the interfacial distance increased. The change of metal induced gap states (MIGS) depends strongly on the interfacial distance but not significantly on the thickness of ZnO nanobelts. An n-type Schottky barrier between copper and ZnO nanobelts is induced by interfacial polarization effects. The Schottky barrier heights for the narrowest and widest nanobelts with equilibrium interfacial spacing were 0.37 eV and 0.44 eV, respectively, which is in good agreement with the experimental values. Additionally, the Schottky barrier heights increased almost linearly as the width of the nanobelts changed from 0.34 nm to 1.2 nm.

  20. Sensitivity Enhancement in Magnetic Sensors Based on Ferroelectric-Bimorphs and Multiferroic Composites.

    PubMed

    Sreenivasulu, Gollapudi; Qu, Peng; Petrov, Vladimir; Qu, Hongwei; Srinivasan, Gopalan

    2016-02-20

    Multiferroic composites with ferromagnetic and ferroelectric phases have been studied in recent years for use as sensors of AC and DC magnetic fields. Their operation is based on magneto-electric (ME) coupling between the electric and magnetic subsystems and is mediated by mechanical strain. Such sensors for AC magnetic fields require a bias magnetic field to achieve pT-sensitivity. Novel magnetic sensors with a permanent magnet proof mass, either on a ferroelectric bimorph or a ferromagnetic-ferroelectric composite, are discussed. In both types, the interaction between the applied AC magnetic field and remnant magnetization of the magnet results in a mechanical strain and a voltage response in the ferroelectric. Our studies have been performed on sensors with a Nd-Fe-B permanent magnet proof mass on (i) a bimorph of oppositely-poled lead zirconate titanate (PZT) platelets and (ii) a layered multiferroic composite of PZT-Metglas-Ni. The sensors have been characterized in terms of sensitivity and equivalent magnetic noise N. Noise N in both type of sensors is on the order of 200 pT/√Hz at 1 Hz, a factor of 10 improvement compared to multiferroic sensors without a proof mass. When the AC magnetic field is applied at the bending resonance for the bimorph, the measured N ≈ 700 pT/√Hz. We discuss models based on magneto-electro-mechanical coupling at low frequency and bending resonance in the sensors and theoretical estimates of ME voltage coefficients are in very good agreement with the data.

  1. Sensitivity Enhancement in Magnetic Sensors Based on Ferroelectric-Bimorphs and Multiferroic Composites

    PubMed Central

    Sreenivasulu, Gollapudi; Qu, Peng; Petrov, Vladimir; Qu, Hongwei; Srinivasan, Gopalan

    2016-01-01

    Multiferroic composites with ferromagnetic and ferroelectric phases have been studied in recent years for use as sensors of AC and DC magnetic fields. Their operation is based on magneto-electric (ME) coupling between the electric and magnetic subsystems and is mediated by mechanical strain. Such sensors for AC magnetic fields require a bias magnetic field to achieve pT-sensitivity. Novel magnetic sensors with a permanent magnet proof mass, either on a ferroelectric bimorph or a ferromagnetic-ferroelectric composite, are discussed. In both types, the interaction between the applied AC magnetic field and remnant magnetization of the magnet results in a mechanical strain and a voltage response in the ferroelectric. Our studies have been performed on sensors with a Nd-Fe-B permanent magnet proof mass on (i) a bimorph of oppositely-poled lead zirconate titanate (PZT) platelets and (ii) a layered multiferroic composite of PZT-Metglas-Ni. The sensors have been characterized in terms of sensitivity and equivalent magnetic noise N. Noise N in both type of sensors is on the order of 200 pT/√Hz at 1 Hz, a factor of 10 improvement compared to multiferroic sensors without a proof mass. When the AC magnetic field is applied at the bending resonance for the bimorph, the measured N ≈ 700 pT/√Hz. We discuss models based on magneto-electro-mechanical coupling at low frequency and bending resonance in the sensors and theoretical estimates of ME voltage coefficients are in very good agreement with the data. PMID:26907290

  2. Electrothermally-Actuated Micromirrors with Bimorph Actuators--Bending-Type and Torsion-Type.

    PubMed

    Tsai, Cheng-Hua; Tsai, Chun-Wei; Chang, Hsu-Tang; Liu, Shih-Hsiang; Tsai, Jui-Che

    2015-01-01

    Three different electrothermally-actuated MEMS micromirrors with Cr/Au-Si bimorph actuators are proposed. The devices are fabricated with the SOIMUMPs process developed by MEMSCAP, Inc. (Durham, NC, USA). A silicon-on-insulator MEMS process has been employed for the fabrication of these micromirrors. Electrothermal actuation has achieved a large angular movement in the micromirrors. Application of an external electric current 0.04 A to the bending-type, restricted-torsion-type, and free-torsion-type mirrors achieved rotation angles of 1.69°, 3.28°, and 3.64°, respectively. PMID:26110409

  3. Energy scavenging based on a single-crystal PMN-PT nanobelt

    PubMed Central

    Wu, Fan; Cai, Wei; Yeh, Yao-Wen; Xu, Shiyou; Yao, Nan

    2016-01-01

    Self-powered nanodevices scavenging mechanical energy require piezoelectric nanostructures with high piezoelectric coefficients. Here we report the fabrication of a single-crystal (1 − x)Pb(Mg1/3Nb2/3)O3 − xPbTiO3 (PMN-PT) nanobelt with a superior piezoelectric constant (d33 = ~550 pm/V), which is approximately ~150%, 430%, and 2100% of the largest reported values for previous PMN-PT, PZT and ZnO nanostructures, respectively. The high d33 of the single-crystalline PMN-PT nanobelt results from the precise orientation control during its fabrication. As a demonstration of its application in energy scavenging, a piezoelectric nanogenerator (PNG) is built on the single PMN-PT nanobelt, generating a maximum output voltage of ~1.2 V. This value is ~4 times higher than that of a single-CdTe PNG, ~13 times higher than that of a single-ZnSnO3 PNG, and ~26 times higher than that of a single-ZnO PNG. The profoundly increased output voltage of a lateral PNG built on a single PMN-PT nanobelt demonstrates the potential application of PMN-PT nanostructures in energy harvesting, thus enriching the material choices for PNGs. PMID:26928788

  4. Gap states assisted MoO3 nanobelt photodetector with wide spectrum response.

    PubMed

    Xiang, Du; Han, Cheng; Zhang, Jialin; Chen, Wei

    2014-05-08

    Molybdenum oxides have been widely investigated for their broad applications ranging from electronics to energy storage. Photodetectors based on molybdenum trioxide (MoO3), however, were seldom reported owing to their low conductivity and weak photoresponse. Herein we report a photodetector based on single MoO3 nanobelt with wide visible spectrum response by introducing substantial gap states via H2 annealing. The pristine MoO3 nanobelt possessed low electrical conductance and no photoresponse for nearly all visible lights. The H2 annealing can significantly improve the conductance of MoO3 nanobelt, and result in a good photodetector with wide visible spectrum response. Under illumination of 680 nm light, the photodetector exhibited high responsivity of ~56 A/W and external quantum efficiency of ~10200%. As corroborated by in situ ultraviolet photoelectron spectroscopy and X-ray photoelectron spectroscopy investigations, such strong wide spectrum photoresponse arises from the largely enriched gap states in the MoO3 nanobelt after H2 annealing.

  5. Energy scavenging based on a single-crystal PMN-PT nanobelt

    NASA Astrophysics Data System (ADS)

    Wu, Fan; Cai, Wei; Yeh, Yao-Wen; Xu, Shiyou; Yao, Nan

    2016-03-01

    Self-powered nanodevices scavenging mechanical energy require piezoelectric nanostructures with high piezoelectric coefficients. Here we report the fabrication of a single-crystal (1 - x)Pb(Mg1/3Nb2/3)O3 - xPbTiO3 (PMN-PT) nanobelt with a superior piezoelectric constant (d33 = ~550 pm/V), which is approximately ~150%, 430%, and 2100% of the largest reported values for previous PMN-PT, PZT and ZnO nanostructures, respectively. The high d33 of the single-crystalline PMN-PT nanobelt results from the precise orientation control during its fabrication. As a demonstration of its application in energy scavenging, a piezoelectric nanogenerator (PNG) is built on the single PMN-PT nanobelt, generating a maximum output voltage of ~1.2 V. This value is ~4 times higher than that of a single-CdTe PNG, ~13 times higher than that of a single-ZnSnO3 PNG, and ~26 times higher than that of a single-ZnO PNG. The profoundly increased output voltage of a lateral PNG built on a single PMN-PT nanobelt demonstrates the potential application of PMN-PT nanostructures in energy harvesting, thus enriching the material choices for PNGs.

  6. Energy scavenging based on a single-crystal PMN-PT nanobelt.

    PubMed

    Wu, Fan; Cai, Wei; Yeh, Yao-Wen; Xu, Shiyou; Yao, Nan

    2016-01-01

    Self-powered nanodevices scavenging mechanical energy require piezoelectric nanostructures with high piezoelectric coefficients. Here we report the fabrication of a single-crystal (1 - x)Pb(Mg1/3Nb2/3)O3 - xPbTiO3 (PMN-PT) nanobelt with a superior piezoelectric constant (d33 = ~550 pm/V), which is approximately ~150%, 430%, and 2100% of the largest reported values for previous PMN-PT, PZT and ZnO nanostructures, respectively. The high d33 of the single-crystalline PMN-PT nanobelt results from the precise orientation control during its fabrication. As a demonstration of its application in energy scavenging, a piezoelectric nanogenerator (PNG) is built on the single PMN-PT nanobelt, generating a maximum output voltage of ~1.2 V. This value is ~4 times higher than that of a single-CdTe PNG, ~13 times higher than that of a single-ZnSnO3 PNG, and ~26 times higher than that of a single-ZnO PNG. The profoundly increased output voltage of a lateral PNG built on a single PMN-PT nanobelt demonstrates the potential application of PMN-PT nanostructures in energy harvesting, thus enriching the material choices for PNGs. PMID:26928788

  7. Gap States Assisted MoO3 Nanobelt Photodetector with Wide Spectrum Response

    PubMed Central

    Xiang, Du; Han, Cheng; Zhang, Jialin; Chen, Wei

    2014-01-01

    Molybdenum oxides have been widely investigated for their broad applications ranging from electronics to energy storage. Photodetectors based on molybdenum trioxide (MoO3), however, were seldom reported owing to their low conductivity and weak photoresponse. Herein we report a photodetector based on single MoO3 nanobelt with wide visible spectrum response by introducing substantial gap states via H2 annealing. The pristine MoO3 nanobelt possessed low electrical conductance and no photoresponse for nearly all visible lights. The H2 annealing can significantly improve the conductance of MoO3 nanobelt, and result in a good photodetector with wide visible spectrum response. Under illumination of 680 nm light, the photodetector exhibited high responsivity of ~56 A/W and external quantum efficiency of ~10200%. As corroborated by in situ ultraviolet photoelectron spectroscopy and X-ray photoelectron spectroscopy investigations, such strong wide spectrum photoresponse arises from the largely enriched gap states in the MoO3 nanobelt after H2 annealing. PMID:24809461

  8. Reverse saturable absorption and nonlinear refraction of ultrathin ZrS3 nanobelts.

    PubMed

    Wu, Jia-Jing; Tao, You-Rong; Wang, Jia-Nan; Wu, Zhong-Yu; Fan, Lei; Wu, Xing-Cai

    2016-05-21

    The nonlinear optical (NLO) properties of a ZrS3 nanobelt were measured with a 6.5 ns pulse laser at 532 nm. Its optical response to the incident light exhibits good optical absorptive and refractive effects, with the nonlinear absorption coefficient β = 4.42 × 10(-10) m W(-1) and the nonlinear refraction coefficient γ = 5.86 × 10(-17) m(2) W(-1) for the ZrS3 nanobelt in ethanol dispersions at an input energy of 34.25 μJ. In addition, the β values and γ values have dependence on input energy. Results show that the ZrS3 nanobelts have an excellent reverse saturable absorption (RSA) performance in nanosecond pulses, demonstrating that ZrS3 nanobelts are an extraordinarily promising novel optical power limiting material. Meanwhile, compared to the pure ZrS3, graphene oxide (GO) and reduced graphene oxide (RGO), composites (ZrS3/GRO) exhibit an enhanced nonlinear absorption response at the same input energy. PMID:27139247

  9. Simple template-free solution route for the synthesis of Ni(SO(4))(0.3)(OH)(1.4) nanobelts and their thermal degradation.

    PubMed

    Tang, Yiwen; Jia, Zhiyong; Jiang, Yun; Li, Luying; Wang, Jianbo

    2006-11-28

    Nanobelts of nickel hydroxyl sulfate have been prepared on a large scale via a simple template-free hydrothermal reaction on the basis of a complex [Ni(NH(3))(6)](2+) formed with Ni(2+) and ammonia in an ethanol-water solution. The as-synthesized nanobelts were single crystals, with several tens of microns in length and 50-150 nm in width. The nanobelts were enclosed by top surfaces (100) and side surfaces (001) and their growth direction was parallel to [010]. The function of aqueous ammonia and ethanol was discussed. Furthermore, nanostructures of a mixture of crystralline NiO and amorphous nickel sulfate with various morphologies, such as nanobelts, porous nanobelts, and nanoparticles, were obtained by the thermal treatment of the as-synthesized Ni(SO(4))(0.3)(OH)(1.4) nanobelts at different temperatures.

  10. Synthesis and electrochemical performance of cable-like copper vanadates/polypyrrole nanobelts as anode materials for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Zhang, Shaoyan; Hou, Menghua; Hou, Linlin; Lu, Min

    2016-08-01

    Cable-like CuV2O6/polypyrrole (CVO/PPy) nanobelts have been synthesized via in-situ oxidative polymerization of pyrrole monomers on the surface of hydrothermally synthesized α-CuV2O6 (CVO) nanobelts. The microscope analysis revealed that the diameter of cable-like CVO/PPy nanobelts focused on 80-110 nm and the shell thickness was about 10-30 nm. The electrochemical properties of the cable-like CVO/PPy nanobelts as anode materials were systematically investigated and compared with bare α-CuV2O6 nanobelts. It was found that the electrochemical performance of the CVO/PPy nanobelts was significantly enhanced. The results suggest that the conductive PPy nanolayer coating help to preserve high capacity, maintain high electrochemical stability, and reduce charge transfer resistance during cycling performance.

  11. Facile solution synthesis and photoelectric properties of monolithic tin(II) sulfide nanobelt arrays.

    PubMed

    Zhang, Xing; Yang, Long; Jiang, Yan; Yu, Bin-Bin; Zou, Yu-Gang; Fang, Ying; Hu, Jin-Song; Wan, Li-Jun

    2013-10-01

    The tremendous future energy demand and environmental concerns prompt the lasting search for new materials for low-cost and high-efficiency solar cells. SnS, as a low-cost, earth-abundant, and environmentally friendly material with proper band gap and absorption coefficient, has received attention as a potential candidate for solar absorber, but it is still under-developed due to insufficient conversion efficiency. Fabricating SnS nanostructured films for solar cell design could be effective to boost photovoltaic performance and pave the way for applications in photovoltaics. Herein, a facile surfactant-free solution-based approach has been developed to prepare monolithic SnS nanostructured films directly on tin foil substrate. The morphologies of nanostructured films could be tuned from well-defined orthorhombic SnS nanobelt arrays to nanorods, nanosheets, or nanoflakes by simply changing the ratio of used solvents. The photoelectric response and electronic transportation properties of SnS nanobelts were investigated by fabricating single-nanobelt-based nanodevices. The SnS nanobelt exhibited a fast and reliable photoresponse even at illumination intensity as weak as 0.103 mW cm(-2). The measurements on SnS FET devices also indicated that the synthesized SnS nanobelts demonstrated a hole mobility as high as 12.33 cm(2) V(-1) s(-1). These results reveal that the reported approach for preparing monolithic SnS nanostructured films could be useful to further develop SnS as an alternative material for low-cost solar cells and electronic devices.

  12. Controlled synthesis of layered Sn3O4 nanobelts by carbothermal reduction method and their gas sensor properties.

    PubMed

    Suman, P H; Longo, E; Varela, J A; Orlandi, M O

    2014-09-01

    This paper reports both the controlled synthesis of Sn3O4 nanobelts by carbothermal reduction method and the gas sensor properties of these nanostructures. The synthesized material was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy and gas sensor measurements. The results showed that the Sn3O4 nanobelts grow in a layered way and the careful control of experimental parameters is fundamental for stabilization of the correct phase. From the gas sensor measurements using oxygen as analyte gas, it was observed that the Sn3O4 nanobelts exhibit n-type behavior and both the sensitivity and the response time are dependent on the oxygen concentration. A model based on molecules adsorption was proposed to illustrate the mechanism of gas detection of these nanostructures. In summary, these results indicate that Sn3O4 nanobelts synthesized by carbothermal reduction method are promising to be applied as gas sensors.

  13. Modeling and simulations of new electrostatically driven, bimorph actuator for high beam steering micromirror deflection angles

    NASA Astrophysics Data System (ADS)

    Walton, John P.; Coutu, Ronald A.; Starman, LaVern

    2015-02-01

    There are numerous applications for micromirror arrays seen in our everyday lives. From flat screen televisions and computer monitors, found in nearly every home and office, to advanced military weapon systems and space vehicles, each application bringing with it a unique set of requirements. The microelectromechanical systems (MEMS) industry has researched many ways micromirror actuation can be accomplished and the different constraints on performance each design brings with it. This paper investigates a new "zipper" approach to electrostatically driven micromirrors with the intent of improving duel plane beam steering by coupling large deflection angles, over 30°, and a fast switching speed. To accomplish this, an extreme initial deflection is needed which can be reached using high stress bimorph beams. Currently this requires long beams and high voltage for the electrostatic pull in or slower electrothermal switching. The idea for this "zipper" approach is to stack multiple beams of a much shorter length and allow for the deflection of each beam to be added together in order to reach the required initial deflection height. This design requires much less pull-in voltage because the pull-in of one short beam will in turn reduce the height of the all subsequent beams, making it much easier to actuate. Using modeling and simulation software to characterize operations characteristics, different bimorph cantilever beam configurations are explored in order to optimize the design. These simulations show that this new "zipper" approach increases initial deflection as additional beams are added to the assembly without increasing the actuation voltage.

  14. Study of oscillatory piezoelectric flow pumps using bimorph actuators with different tip geometries

    NASA Astrophysics Data System (ADS)

    Pires, Rogério F.; Koga, Adriano A.; Nakasone, Paulo H.; Silva, Emílio C. N.

    2008-03-01

    Precision flow pumps have been widely studied over the last three decades. They have been applied in the areas of Biology, Pharmacy and Medicine in applications usually related to the dosage of medicine and chemical reagents. In addition, thermal management solutions for electronic devices have also been recently developed using these kinds of pumps offering better performance with low noise and low power consumption. In a previous work, the working principle of a pump based on the use of bimorph piezoelectric actuators inserted in a fluid channel to generate flow was presented. The present work aims at the development of novel configurations of piezoelectric flow pumps based on the use of bimorph actuators with biomimetic tip geometries that are inspired in fish caudal fin shapes, such as ostraciiform, subcarangiform, carangiform and thunniform. The pump development consists in designing, manufacturing and experimental characterization steps. In the design step, computational models of pump configurations are built to perform sensitivity studies and to apply optimization techniques using ANSYS finite element analysis software. The prototype manufacturing is guided by the computational simulations. Electronic circuits for pump electrical excitation and control are developed and implemented. Comparisons among numerical and experimental results are also made.

  15. Out-of-Plane Translational PZT Bimorph Actuator with Archimedes’ Spiral Actuating Tethers

    NASA Astrophysics Data System (ADS)

    Yang, Chenye; Liu, Sanwei; Livermore, Carol

    2015-12-01

    The design, finite element analysis (FEA), and experimental characterization of a MEMS out-of-plane (vertical) translational lead-zirconate-titanate (PZT) bimorph actuator supported on Archimedes’ spiral tethers are presented. Two types of bimorph actuators with different electrode patterns (with spiral tethers half actuated or fully actuated) are designed and fabricated. Both designs are fabricated by commercial processes and are compatible with integration into more complex MEMS systems. Finite element analysis (FEA) was used to analyze and predict the displacements of both types of actuators. The deflections of both fully- actuated and half-actuated devices were measured experimentally to validate the design. At an applied voltage of 110V, the out-of-plane deflections of the actuators with half-actuated and fully-actuated tethers were measured at about 17 μm and 29 μm respectively, in good agreement with FEA predictions of 17.1 μm and 25.8 μm. The corresponding blocking forces are predicted as 10 mN and 17 mN by FEA.

  16. An analytical solution for the magneto-electro-elastic bimorph beam forced vibrations problem

    NASA Astrophysics Data System (ADS)

    Milazzo, A.; Orlando, C.; Alaimo, A.

    2009-08-01

    Based on the Timoshenko beam theory and on the assumption that the electric and magnetic fields can be treated as steady, since elastic waves propagate very slowly with respect to electromagnetic ones, a general analytical solution for the transient analysis of a magneto-electro-elastic bimorph beam is obtained. General magneto-electric boundary conditions can be applied on the top and bottom surfaces of the beam, allowing us to study the response of the bilayer structure to electromagnetic stimuli. The model reveals that the magneto-electric loads enter the solution as an equivalent external bending moment per unit length and as time-dependent mechanical boundary conditions through the definition of the bending moment. Moreover, the influences of the electro-mechanic, magneto-mechanic and electromagnetic coupling on the stiffness of the bimorph stem from the computation of the beam equivalent stiffness constants. Free and forced vibration analyses of both multiphase and laminated magneto-electro-elastic composite beams are carried out to check the effectiveness and reliability of the proposed analytic solution.

  17. Construction of a Fish‐like Robot Based on High Performance Graphene/PVDF Bimorph Actuation Materials

    PubMed Central

    Xiao, Peishuang; Yi, Ningbo; Zhang, Tengfei; Chang, Huicong; Yang, Yang; Zhou, Ying

    2016-01-01

    Smart actuators have many potential applications in various areas, so the development of novel actuation materials, with facile fabricating methods and excellent performances, are still urgent needs. In this work, a novel electromechanical bimorph actuator constituted by a graphene layer and a PVDF layer, is fabricated through a simple yet versatile solution approach. The bimorph actuator can deflect toward the graphene side under electrical stimulus, due to the differences in coefficient of thermal expansion between the two layers and the converse piezoelectric effect and electrostrictive property of the PVDF layer. Under low voltage stimulus, the actuator (length: 20 mm, width: 3 mm) can generate large actuation motion with a maximum deflection of about 14.0 mm within 0.262 s and produce high actuation stress (more than 312.7 MPa/g). The bimorph actuator also can display reversible swing behavior with long cycle life under high frequencies. on this basis, a fish‐like robot that can swim at the speed of 5.02 mm/s is designed and demonstrated. The designed graphene‐PVDF bimorph actuator exhibits the overall novel performance compared with many other electromechanical avtuators, and may contribute to the practical actuation applications of graphene‐based materials at a macro scale.

  18. Analytical modeling and experimental verification of vibration-based piezoelectric bimorph beam with a tip-mass for power harvesting

    NASA Astrophysics Data System (ADS)

    Wang, Hongjin; Meng, Qingfeng

    2013-03-01

    Power harvesting techniques that convert vibration energy into electrical energy through piezoelectric transducers show strong potential for powering smart wireless sensor devices in applications of structural health monitoring. This paper presents an analytical model of the dynamic behavior of an electromechanical piezoelectric bimorph cantilever harvester connected with an AC-DC circuit based on the Euler-Bernoulli beam theory and Hamiltonian theorem. A new cantilevered piezoelectric bimorph structure is proposed in which the plug-type connection between support layer and tip-mass ensures that the gravity center of the tip-mass is collinear with the gravity center of the beam so that the brittle fracture of piezoelectric layers can also be avoided while vibrating with large amplitude. The tip-mass is equated by the inertial force and inertial moment acting at the end of the piezoelectric bimorph beam based on D'Alembert's principle. An AC-DC converting circuit soldered with the piezoelectric elements is also taken into account. A completely new analytic expression of the global behavior of the electromechanical piezoelectric bimorph harvesting system with AC-DC circuit under input base transverse excitation is derived. Moreover, an experimental energy harvester is fabricated and the theoretical analysis and experimental results of the piezoelectric harvester under the input base transverse displacement excitation are validated by using measurements of the absolute tip displacement, electric voltage response, electric current response and electric power harvesting.

  19. Synthesis of porous and nonporous ZnO nanobelt, multipod, and hierarchical nanostructure from Zn-HDS

    SciTech Connect

    Jang, Eue-Soon; Won, Jung-Hee; Kim, Young-Woon; Cheng, Zhen; Choy, Jin-Ho

    2010-08-15

    Zn based hydroxide double salts (Zn-HDS) with an interlayer spacing of 20 A was produced by dissolving dumbbell-like ZnO crystal. The resulting Zn-HDS with a ribbon-like shape has a suitable morphology to explore the remarkably mild procedure for synthesis of ZnO nanobelts. We found that the intercalated water molecules into the Zn-HDS could play a key role in the ZnO nanobelts porosity. The nonporous ZnO nanobelts were successfully synthesized from the Zn-HDS by soft-solution process at 95 {sup o}C through mild dehydration agent as Na{sub 2}CO{sub 3}. As-synthesized ZnO nanobelts were grown along not only the [0 1 -1 0], but also the [2 -1 -1 0]. On the other hand, the porous ZnO nanobelts were obtained from the Zn-HDS by calcinations at 200 and 400 {sup o}C. In addition, flower-like ZnO multipod and hierarchical nanostructures were produced from the Zn-HDS by using of strong dehydration agent (NaOH) through hydrothermal reaction at 150 and 230 {sup o}C. - Graphical abstract: Porous and nonporous ZnO nanobelts, multipod, and hierarchical nanostructure were successfully synthesized from Zn based hydroxyl double salts by hydrothermal reaction.

  20. Hydrothermal Synthesis of Silver Vanadium Oxide (Ag0.35V2O5) Nanobelts for Sensing Amines

    NASA Astrophysics Data System (ADS)

    Fu, Haitao; Xie, Hui; Yang, Xiaohong; An, Xizhong; Jiang, Xuchuan; Yu, Aibing

    2015-10-01

    A simple hydrothermal method for the synthesis of Ag0.35V2O5 nanobelts with the assistance of sodium dodecyl sulfate (SDS) is reported in this study. The experimental variables that may affect the nanoparticle structures were investigated. And several advanced techniques, such as TEM, HRTEM, X-ray diffraction (XRD), were used to characterize the morphology and composition of the as-prepared nanobelts. The mechanism of the formation and growth of Ag0.35V2O5 nanobelts was also investigated and discussed. The results show that SDS, as a weak reducing agent, plays a crucial role in the formation of Ag0.35V2O5. According to N2 sorption isothermals, the as-prepared Ag0.35V2O5 nanobelts are found to exhibit relative high surface area. The gas sensing performance of the Ag0.35V2O5 nanobelts towards organic amine was tested. It is found that the nanobelts show superior sensitivity of amine(s) to V2O5 particles, lower detection limit (5 ppm), and higher selectivity of amine versus ammonia at an optimized working temperature of ~260 °C. Moreover, the density functional theory (DFT) simulation was conducted to better understand the sensing mechanism. These findings may be useful in designing promising materials to detect amine gases for medical or food industrial applications.

  1. Tailored Electrospinning of WO₃ Nanobelts as Efficient Ultraviolet Photodetectors with Photo-Dark Current Ratios up to 1000.

    PubMed

    He, Zhiyang; Liu, Qiao; Hou, Huilin; Gao, Fengmei; Tang, Bin; Yang, Weiyou

    2015-05-27

    In this work, polycrystalline WO3 nanobelts were fabricated via an electrospinning process combined with subsequent air calcination. The resultant products were characterized by X-ray diffraction, field-emission scanning electron microscopy, and high-resolution transmission electron microscopy in regard to the structures. It has been found that the applied voltage during the electrospinning process played the determined role in the formation of the WO3 nanobelts, allowing the controlled growth of the nanobelts. The ultraviolet (UV) photodetector assembled by an individual WO3 nanobelt exhibits a high sensitivity and a precise selectivity to the different wavelength lights, with a very low dark current and typical photo-dark current ratio up to 1000, which was the highest for any WO3 photodectectors ever reported. This work could not only push forward the facile preparation of WO3 nanobelts but also represent, for the first time, the possibility that the polycrystalline WO3 nanobelts could be a promising building block for the highly efficient UV photodetectors.

  2. Broadband piezoelectric energy harvesting devices using multiple bimorphs with different operating frequencies.

    PubMed

    Xue, Huan; Hu, Yuantai; Wang, Qing-Ming

    2008-09-01

    This paper presents a novel approach for designing broadband piezoelectric harvesters by integrating multiple piezoelectric bimorphs (PBs) with different aspect ratios into a system. The effect of 2 connecting patterns among PBs, in series and in parallel, on improving energy harvesting performance is discussed. It is found for multifrequency spectra ambient vibrations: 1) the operating frequency band (OFB) of a harvesting structure can be widened by connecting multiple PBs with different aspect ratios in series; 2) the OFB of a harvesting structure can be shifted to the dominant frequency domain of the ambient vibrations by increasing or decreasing the number of PBs in parallel. Numerical results show that the OFB of the piezoelectric energy harvesting devices can be tailored by the connection patterns (i.e., in series and in parallel) among PBs. PMID:18986908

  3. Design and analysis of a connected broadband multi-piezoelectric-bimorph- beam energy harvester.

    PubMed

    Zhang, Haifeng; Afzalul, Karim

    2014-06-01

    The rapid growth of remote, wireless, and microelectromechanical system (MEMS) devices over the past decades has motivated the development of a self-powered system that can replace traditional electrochemical batteries. Piezoelectric energy harvesters are ideal for capturing energy from mechanical vibrations in the ambient environment. Numerous studies have been made of this application of piezoelectric energy conversion; however, the narrow frequency operation band has limited its application to generate useful power. In this paper, a broadband energy harvester with an array/matrix of piezoelectric bimorphs connected by springs has been designed and analyzed based on the 1-D piezoelectric beam equations. The predicted result shows that the operational frequency band can be enlarged significantly by carefully adjusting the small end masses, length of the beam and spring stiffness. An optimal selection of the load impedance to realize the maximum power output is discussed. The results provide an important foundation for future broadband energy harvester design. PMID:24859665

  4. Design and analysis of a connected broadband multi-piezoelectric-bimorph- beam energy harvester.

    PubMed

    Zhang, Haifeng; Afzalul, Karim

    2014-06-01

    The rapid growth of remote, wireless, and microelectromechanical system (MEMS) devices over the past decades has motivated the development of a self-powered system that can replace traditional electrochemical batteries. Piezoelectric energy harvesters are ideal for capturing energy from mechanical vibrations in the ambient environment. Numerous studies have been made of this application of piezoelectric energy conversion; however, the narrow frequency operation band has limited its application to generate useful power. In this paper, a broadband energy harvester with an array/matrix of piezoelectric bimorphs connected by springs has been designed and analyzed based on the 1-D piezoelectric beam equations. The predicted result shows that the operational frequency band can be enlarged significantly by carefully adjusting the small end masses, length of the beam and spring stiffness. An optimal selection of the load impedance to realize the maximum power output is discussed. The results provide an important foundation for future broadband energy harvester design.

  5. Production of large-scale, freestanding vanadium pentoxide nanobelt porous structures

    NASA Astrophysics Data System (ADS)

    Yun, Yong Ju; Kim, Byung Hoon; Hong, Won G.; Kim, Chang Hee; Kim, Yark Yeon; Jeong, Eun-Ju; Jang, Won Ick; Yu, Han Young

    2012-02-01

    Large-scale, freestanding, porous structures of vanadium pentoxide nanobelts (VPNs) were successfully prepared using the template-free freeze-drying method. The porous and multi-layered VPN macrostructures are composed of randomly oriented long nanobelts (over 100 μm) and their side length can be controlled up to a few tens of centimetres. Also, the bulk density and surface area of these macrostructures are 3-5 mg cm-3 and 40-80 m2 g-1, respectively, which are similar to those of the excellent adsorbents. In addition, the removal efficiency measurements of ammonia molecules revealed that the VPN porous structures can adsorb the ammonia molecules with the combinations of van der Waals forces and strong chemical bonding by functional groups on the VPN surface.

  6. Production of large-scale, freestanding vanadium pentoxide nanobelt porous structures.

    PubMed

    Yun, Yong Ju; Kim, Byung Hoon; Hong, Won G; Kim, Chang Hee; Kim, Yark Yeon; Jeong, Eun-ju; Jang, Won Ick; Yu, Han Young

    2012-03-01

    Large-scale, freestanding, porous structures of vanadium pentoxide nanobelts (VPNs) were successfully prepared using the template-free freeze-drying method. The porous and multi-layered VPN macrostructures are composed of randomly oriented long nanobelts (over 100 μm) and their side length can be controlled up to a few tens of centimetres. Also, the bulk density and surface area of these macrostructures are 3-5 mg cm(-3) and 40-80 m(2) g(-1), respectively, which are similar to those of the excellent adsorbents. In addition, the removal efficiency measurements of ammonia molecules revealed that the VPN porous structures can adsorb the ammonia molecules with the combinations of van der Waals forces and strong chemical bonding by functional groups on the VPN surface.

  7. S-induced modifications of the optoelectronic properties of ZnO mesoporous nanobelts

    NASA Astrophysics Data System (ADS)

    Fabbri, Filippo; Nasi, Lucia; Fedeli, Paolo; Ferro, Patrizia; Salviati, Giancarlo; Mosca, Roberto; Calzolari, Arrigo; Catellani, Alessandra

    2016-06-01

    The synthesis of ZnO porous nanobelts with high surface-to-volume ratio is envisaged to enhance the zinc oxide sensing and photocatalytic properties. Yet, controlled stoichiometry, doping and compensation of as-grown n-type behavior remain open problems for this compound. Here, we demonstrate the effect of residual sulfur atoms on the optical properties of ZnO highly porous, albeit purely wurtzite, nanobelts synthesized by solvothermal decomposition of ZnS hybrids. By means of combined cathodoluminescence analyses and density functional theory calculations, we attribute a feature appearing at 2.36 eV in the optical emission spectra to sulfur related intra-gap states. A comparison of different sulfur configurations in the ZnO matrix demonstrates the complex compensating effect on the electronic properties of the system induced by S-inclusion.

  8. S-induced modifications of the optoelectronic properties of ZnO mesoporous nanobelts.

    PubMed

    Fabbri, Filippo; Nasi, Lucia; Fedeli, Paolo; Ferro, Patrizia; Salviati, Giancarlo; Mosca, Roberto; Calzolari, Arrigo; Catellani, Alessandra

    2016-01-01

    The synthesis of ZnO porous nanobelts with high surface-to-volume ratio is envisaged to enhance the zinc oxide sensing and photocatalytic properties. Yet, controlled stoichiometry, doping and compensation of as-grown n-type behavior remain open problems for this compound. Here, we demonstrate the effect of residual sulfur atoms on the optical properties of ZnO highly porous, albeit purely wurtzite, nanobelts synthesized by solvothermal decomposition of ZnS hybrids. By means of combined cathodoluminescence analyses and density functional theory calculations, we attribute a feature appearing at 2.36 eV in the optical emission spectra to sulfur related intra-gap states. A comparison of different sulfur configurations in the ZnO matrix demonstrates the complex compensating effect on the electronic properties of the system induced by S-inclusion. PMID:27301986

  9. Raman selection rule for surface optical phonons in ZnS nanobelts.

    PubMed

    Ho, Chih-Hsiang; Varadhan, Purushothaman; Wang, Hsin-Hua; Chen, Cheng-Ying; Fang, Xiaosheng; He, Jr-Hau

    2016-03-21

    We report Raman scattering results for high-quality wurtzite ZnS nanobelts (NBs) grown by chemical vapor deposition. In the Raman spectrum, the ensembles of ZnS NBs exhibit first order phonon modes at 274 cm(-1) and 350 cm(-1), corresponding to A1/E1 transverse optical and A1/E1 longitudinal optical phonons, in addition to a strong surface optical (SO) phonon mode at 329 cm(-1). The existence of the SO band is confirmed by its shift with different surrounding dielectric media. Polarization dependent Raman spectra were recorded on a single ZnS NB and for the first time a SO phonon band has been detected on a single nanobelt. Different selection rules for the SO phonon mode are shown from their corresponding E1/A1 phonon modes, and were attributed to the breaking of anisotropic translational symmetry on the NB surface. PMID:26924069

  10. S-induced modifications of the optoelectronic properties of ZnO mesoporous nanobelts

    PubMed Central

    Fabbri, Filippo; Nasi, Lucia; Fedeli, Paolo; Ferro, Patrizia; Salviati, Giancarlo; Mosca, Roberto; Calzolari, Arrigo; Catellani, Alessandra

    2016-01-01

    The synthesis of ZnO porous nanobelts with high surface-to-volume ratio is envisaged to enhance the zinc oxide sensing and photocatalytic properties. Yet, controlled stoichiometry, doping and compensation of as-grown n-type behavior remain open problems for this compound. Here, we demonstrate the effect of residual sulfur atoms on the optical properties of ZnO highly porous, albeit purely wurtzite, nanobelts synthesized by solvothermal decomposition of ZnS hybrids. By means of combined cathodoluminescence analyses and density functional theory calculations, we attribute a feature appearing at 2.36 eV in the optical emission spectra to sulfur related intra-gap states. A comparison of different sulfur configurations in the ZnO matrix demonstrates the complex compensating effect on the electronic properties of the system induced by S-inclusion. PMID:27301986

  11. Solid-state semiconductor optical cryocooler based on CdS nanobelts.

    PubMed

    Li, Dehui; Zhang, Jun; Wang, Xinjiang; Huang, Baoling; Xiong, Qihua

    2014-08-13

    We demonstrate the laser cooling of silicon-on-insulator (SOI) substrate using CdS nanobelts. The local temperature change of the SOI substrate exactly beneath the CdS nanobelts is deduced from the ratio of the Stokes and anti-Stokes Raman intensities from the Si layer on the top of the SOI substrate. We have achieved a 30 and 20 K net cooling starting from 290 K under a 3.8 mW 514 nm and a 4.4 mW 532 nm pumping, respectively. In contrast, a laser heating effect has been observed pumped by 502 and 488 nm lasers. Theoretical analysis based on the general static heat conduction module in the Ansys program package is conducted, which agrees well with the experimental results. Our investigations demonstrate the laser cooling capability of an external thermal load, suggesting the applications of II-VI semiconductors in all-solid-state optical cryocoolers.

  12. A novel polytype - the stacking fault based γ-MoO3 nanobelts.

    PubMed

    Sławiński, Wojciech A; Fjellvåg, Øystein S; Ruud, Amund; Fjellvåg, Helmer

    2016-04-01

    γ-MoO3 nanobelts prepared by hydrothermal synthesis were studied by synchrotron radiation powder diffraction, scanning electron microscopy, transmission electron microscopy and selected area electron diffraction. Their nm dimensions, in particular in two crystallographic directions, have a profound influence on electrochemical properties during cycling as the cathode material in lithium-ion batteries (LIBs). The diffraction analysis shows clearly that the crystal structure for the γ-MoO3 nanobelts differs significantly from that of bulk α-MoO3. The observed powder diffraction pattern, with asymmetric peaks, extremely broad peaks, as well as additional or absent diffraction peaks, is fully described by means of a model based on stacking disorder of MoO3 slabs. PMID:27048722

  13. Quantitative electromechanical impedance method for nondestructive testing based on a piezoelectric bimorph cantilever

    NASA Astrophysics Data System (ADS)

    Fu, Ji; Tan, Chi; Li, Faxin

    2015-06-01

    The electromechanical impedance (EMI) method, which holds great promise in structural health monitoring (SHM), is usually treated as a qualitative method. In this work, we proposed a quantitative EMI method based on a piezoelectric bimorph cantilever using the sample’s local contact stiffness (LCS) as the identification parameter for nondestructive testing (NDT). Firstly, the equivalent circuit of the contact vibration system was established and the analytical relationship between the cantilever’s contact resonance frequency and the LCS was obtained. As the LCS is sensitive to typical defects such as voids and delamination, the proposed EMI method can then be used for NDT. To verify the equivalent circuit model, two piezoelectric bimorph cantilevers were fabricated and their free resonance frequencies were measured and compared with theoretical predictions. It was found that the stiff cantilever’s EMI can be well predicted by the equivalent circuit model while the soft cantilever’s cannot. Then, both cantilevers were assembled into a homemade NDT system using a three-axis motorized stage for LCS scanning. Testing results on a specimen with a prefabricated defect showed that the defect could be clearly reproduced in the LCS image, indicating the validity of the quantitative EMI method for NDT. It was found that the single-frequency mode of the EMI method can also be used for NDT, which is faster but not quantitative. Finally, several issues relating to the practical application of the NDT method were discussed. The proposed EMI-based NDT method offers a simple and rapid solution for damage evaluation in engineering structures and may also shed some light on EMI-based SHM.

  14. Fast visible light photoelectric switch based on ultralong single crystalline V₂O₅ nanobelt.

    PubMed

    Lu, Jianing; Hu, Ming; Tian, Ye; Guo, Chuanfei; Wang, Chuang; Guo, Shengming; Liu, Qian

    2012-03-26

    A photoelectric switch with fast response to visible light (<200 μs), suitable photosensitivity and excellent repeatability is proposed based on the ultralong single crystalline V₂O₅ nanobelt, which are synthesized by chemical vapor deposition and its photoconductive mechanism can well be explained by small polaron hopping theory. Our results reveal that the switch has a great potential in next generation photodetectors and light-wave communications.

  15. Synthesis and electrical properties of In2O3(ZnO)m superlattice nanobelt

    NASA Astrophysics Data System (ADS)

    Tang, Xin-Yue; Gao, Hong; Wu, Li-Li; Wen, Jing; Pan, Si-Ming; Liu, Xin; Zhang, Xi-Tian

    2015-02-01

    One-dimensional (1D) In2O3(ZnO)m superlattice nanobelts are synthesized by a chemical vapor deposition method. The formation of the In2O3(ZnO)m superlattice is verified by the high-resolution transmission electron microscopy images. The typical zigzag boundaries could be clearly observed. An additional peak at 614 cm-1 is found in the Raman spectrum, which may correspond to the superlattice structure. The study about the electrical transport properties reveals that the In2O3(ZnO)m nanobelts exhibit peculiar nonlinear I-V characteristics even under the Ohmic contact measurement condition, which are different from the Ohmic behaviors of the In-doped ZnO nanobelts. The photoelectrical measurements show the differences in the photocurrent property between them, and their transport mechanisms are also discussed. Project supported by the National Natural Science Foundation of China (Grant No. 51172058), the Key Project of the Science Technology and Research Project of Education Bureau, Heilongjiang Province, China (Grant No. 12521z012), and the Natural Science Foundation of Heilongjiang Province for Returned Chinese Scholars, China (Grant No. LC2013C17).

  16. Mesoporous single-crystal ZnO nanobelts: supported preparation and patterning.

    PubMed

    Nasi, Lucia; Calestani, Davide; Fabbri, Filippo; Ferro, Patrizia; Besagni, Tullo; Fedeli, Paolo; Licci, Francesca; Mosca, Roberto

    2013-02-01

    We demonstrate that highly porous ZnO nanobelts can be prepared by thermally decomposing ZnS(en)(0.5) hybrid nanobelts (NBs) synthesized through a solvothermal route using Zn layers deposited on alumina substrates as both the Zn substrate and source. Hybrid decomposition by thermal annealing at 400 °C gives porous ZnS NBs that are transformed by further annealing at 600 °C into wurtzite single crystal ZnO nanobelts with an axial direction of [0001]. The evolution of the morphological and structural transformation ZnS(en)(0.5)→ ZnS → ZnO is investigated at the nanoscale by transmission and scanning electron microscopy analyses. Control of the ZnO NB distributions by patterning the Zn metallization on alumina is achieved as a consequence of the parent hybrid NB patterned growth. The presence of NBs on alumina in a ∼100 μm wide region between Zn stripes allows us to fabricate two contact devices where contact pads are electrically connected through a porous ZnO NB entanglement. Such devices are suitable for employment in photodetectors as well as in gas and humidity sensors.

  17. A Single Eu-Doped In₂O₃ Nanobelt Device for Selective H₂S Detection.

    PubMed

    Chen, Weiwu; Liu, Yingkai; Qin, Zhaojun; Wu, Yuemei; Li, Shuanghui; Ai, Peng

    2015-01-01

    Eu-doped In₂O₃ nanobelts (Eu-In₂O₃ NBs) and pure In₂O₃ nanobelts (In₂O₃ NBs) are synthesized by the carbon thermal reduction method. Single nanobelt sensors are fabricated via an ion beam deposition system with a mesh-grid mask. The gas-sensing response properties of the Eu-In₂O₃ NB device and its undoped counterpart are investigated with several kinds of gases (including H₂S, CO, NO₂, HCHO, and C₂H₅OH) at different concentrations and different temperatures. It is found that the response of the Eu-In₂O₃ NB device to 100 ppm of H₂S is the best among these gases and the sensitivity reaches 5.74, which is five times that of pure In₂O₃ NB at 260 °C. We also found that the former has an excellent sensitive response and great selectivity to H₂S compared to the latter. Besides, there is a linear relationship between the response and H₂S concentration when its concentration changes from 5 to 100 ppm and from 100 to 1000 ppm. The response/recovery time is quite short and remains stable with an increase of H₂S concentration. These results mean that the doping of Eu can improve the gas-sensing performance of In₂O₃ NB effectually. PMID:26633404

  18. Electrical observation of sub-band formation in SnO2 nanobelts.

    PubMed

    Viana, E R; González, J C; Ribeiro, G M; de Oliveira, A G

    2013-07-21

    The electrical observation of energy sub-band formation in the electronic structure, that gives rise to the phenomenon of quantized transport is reported in tin oxide (SnO2) nanobelt back-gate field-effect transistors, at low temperatures. Sub-band formation was observed as current oscillations in the drain current vs. gate voltage characteristics, and was analyzed considering the nanobelt as a "quantum wire" with a rectangular cross-section and hard walls. The lateral quantum confinement in the nanowires created conditions for the successive filling of the first twelve electron energy sub-bands, as the gate voltage increases. When the source-drain voltage is changed, the oscillations are not dislocated with respect to the gate voltage indicating flat-band energies, and that the observations are incompatible with the phenomena of Coulomb blockade and tunnelling oscillations. The separation of the energy sub-bands was found to be in good agreement with the measured cross-section dimensions of the nanobelt and with the threshold temperature, since for T > 60 K the oscillations tend to vanish.

  19. Bifunctional Ag/C3N4.5 composite nanobelts for photocatalysis and antibacterium.

    PubMed

    Lei, Renbo; Jian, Jikang; Zhang, Zhihua; Song, Bo; Wu, Rong

    2016-09-30

    Multiple functions can be achieved in carbon nitride-based composite nanomaterials by tuning their components and structures. Here, we report on a large-scale synthesis of novel bifunctional Ag/C3N4.5 composite nanobelts (CNBs) with efficient photocatalytic and antibacterial activity. The Ag/C3N4.5 CNBs were synthesized in high yield by a two-step route including a homogeneous precipitation process and a subsequent calcination treatment. The structural, morphological, compositional, and spectroscopic characterizations revealed that the Ag/C3N4.5 CNBs are composed of N-deficient melem ultrathin nanobelts and crystalline Ag nanoparticles attached to the surface of the nanobelts with good contact. The band gap of the Ag/C3N4.5 CNBs is determined to be about 3.04 eV. The efficient photocatalytic and antibacterial activities of the composite nanomaterials are verified by testing the degradation of Rhodamine B (RhB) and the inhibition zone to bacterium E. coli. The work provides a facile route to bifunctional carbon nitride-based composites with potential applications in the fields of the environment and biology.

  20. Bifunctional Ag/C3N4.5 composite nanobelts for photocatalysis and antibacterium

    NASA Astrophysics Data System (ADS)

    Lei, Renbo; Jian, Jikang; Zhang, Zhihua; Song, Bo; Wu, Rong

    2016-09-01

    Multiple functions can be achieved in carbon nitride-based composite nanomaterials by tuning their components and structures. Here, we report on a large-scale synthesis of novel bifunctional Ag/C3N4.5 composite nanobelts (CNBs) with efficient photocatalytic and antibacterial activity. The Ag/C3N4.5 CNBs were synthesized in high yield by a two-step route including a homogeneous precipitation process and a subsequent calcination treatment. The structural, morphological, compositional, and spectroscopic characterizations revealed that the Ag/C3N4.5 CNBs are composed of N-deficient melem ultrathin nanobelts and crystalline Ag nanoparticles attached to the surface of the nanobelts with good contact. The band gap of the Ag/C3N4.5 CNBs is determined to be about 3.04 eV. The efficient photocatalytic and antibacterial activities of the composite nanomaterials are verified by testing the degradation of Rhodamine B (RhB) and the inhibition zone to bacterium E. coli. The work provides a facile route to bifunctional carbon nitride-based composites with potential applications in the fields of the environment and biology.

  1. Synthesis and Gas Sensing Properties of Single La-Doped SnO2 Nanobelts

    PubMed Central

    Wu, Yuemei; Zhang, Heng; Liu, Yingkai; Chen, Weiwu; Ma, Jiang; Li, Shuanghui; Qin, Zhaojun

    2015-01-01

    Single crystal SnO2 nanobelts (SnO2 NBs) and La-SnO2 nanobelts (La-SnO2 NBs) were synthesized by thermal evaporation. Both a single SnO2 NB sensor and a single La-SnO2 NB sensor were developed and their sensing properties were investigated. It is found that the single La-SnO2 NB sensor had a high sensitivity of 8.76 to ethanediol at a concentration of 100 ppm at 230 °C, which is the highest sensitivity of a single SnO2 NB to ethanediol among three kinds of volatile organic (VOC) liquids studied, including ethanediol, ethanol, and acetone. The La-SnO2 NBs sensor also exhibits a high sensitivity, good selectivity and long-term stability with prompt response time to ethanediol. The mechanism behind the enhanced sensing performance of La-doped SnO2 nanobelts is discussed. PMID:26087374

  2. Synthesis and Gas Sensing Properties of Single La-Doped SnO₂ Nanobelts.

    PubMed

    Wu, Yuemei; Zhang, Heng; Liu, Yingkai; Chen, Weiwu; Ma, Jiang; Li, Shuanghui; Qin, Zhaojun

    2015-06-16

    Single crystal SnO2 nanobelts (SnO2 NBs) and La-SnO2 nanobelts (La-SnO2 NBs) were synthesized by thermal evaporation. Both a single SnO2 NB sensor and a single La-SnO2 NB sensor were developed and their sensing properties were investigated. It is found that the single La-SnO2 NB sensor had a high sensitivity of 8.76 to ethanediol at a concentration of 100 ppm at 230 °C, which is the highest sensitivity of a single SnO2 NB to ethanediol among three kinds of volatile organic (VOC) liquids studied, including ethanediol, ethanol, and acetone. The La-SnO2 NBs sensor also exhibits a high sensitivity, good selectivity and long-term stability with prompt response time to ethanediol. The mechanism behind the enhanced sensing performance of La-doped SnO2 nanobelts is discussed.

  3. Ultrathin Na1.1V3O7.9 nanobelts with superior performance as cathode materials for lithium-ion batteries.

    PubMed

    Liang, Shuquan; Zhou, Jiang; Fang, Guozhao; Liu, Jing; Tang, Yan; Li, Xilin; Pan, Anqiang

    2013-09-11

    The Na1.1V3O7.9 nanobelts have been synthesized by a facile and scalable hydrothermal reaction with subsequent calcinations. The morphologies and the crystallinity of the nanobelts are largely determined by the calcination temperatures. Ultrathin nanobelts with a thickness around 20 nm can be obtained, and the TEM reveals that the nanobelts are composed of many stacked thinner belts. When evaluated as a cathode material for lithium batteries, the Na1.1V3O7.9 nanobelts exhibit high specific capacity, good rate capability, and superior long-term cyclic stability. A high specific capacity of 204 mA h g(-1) can be delivered at the current density of 100 mA g(-1). It shows excellent capacity retention of 95% after 200 cycles at the current density of 1500 mA g(-1). As demonstrated by the ex situ XRD results, the Na1.1V3O7.9 nanobelts have very good structural stability upon cycling. The superior electrochemical performances can be attributed to the ultra-thin nanobelts and the good structural stability of the Na1.1V3O7.9 nanobelts.

  4. Hysteresis-free high-temperature precise bimorph actuators produced by direct bonding of lithium niobate wafers

    SciTech Connect

    Shur, V. Ya.; Baturin, I. S.; Mingaliev, E. A.; Zorikhin, D. V.; Udalov, A. R.; Greshnyakov, E. D.

    2015-02-02

    The current paper presents a piezoelectric bimorph actuator produced by direct bonding of lithium niobate wafers with the mirrored Y and Z axes. Direct bonding technology allowed to fabricate bidomain plate with precise positioning of ideally flat domain boundary. By optimizing the cutting angle (128° Y-cut), the piezoelectric constant became as large as 27.3 pC/N. Investigation of voltage dependence of bending displacement confirmed that bimorph actuator has excellent linearity and hysteresis-free. Decrease of the applied voltage down to mV range showed the perfect linearity up to the sub-nm deflection amplitude. The frequency and temperature dependences of electromechanical transmission coefficient in wide temperature range (from 300 to 900 K) were investigated.

  5. Cable suspended windmill

    SciTech Connect

    Farmer, M.G.

    1990-01-16

    This patent describes a windmill apparatus. It comprises: an airframe having an upwind end and a downwind end; a first rotor rotatably mounted on the airframe; a generator supported by the airframe and being operatively connected to the rotor; ground based support means for supporting the airframe in a vertically elevated disposition; and suspension means for suspending the airframe from the support means.

  6. Ariad suspends ponatinib sales.

    PubMed

    2014-01-01

    Because of concerns about serious cardiovascular side effects, the U.S. Food and Drug Administration asked Ariad Pharmaceuticals to temporarily suspend sales and marketing of ponatinib to treat chronic myeloid leukemia in patients resistant to first-line therapy. PMID:24402926

  7. Piezoelectric bimorph-based scanner in the tip-scan mode for high speed atomic force microscope

    NASA Astrophysics Data System (ADS)

    Zhao, Jianyong; Gong, Weitao; Cai, Wei; Shang, Guangyi

    2013-08-01

    A piezoelectric bimorph-based scanner operating in tip-scan mode for high speed atomic force microscope (AFM) is first presented. The free end of the bimorph is used for fixing an AFM cantilever probe and the other one is mounted on the AFM head. The sample is placed on the top of a piezoelectric tube scanner. High speed scan is performed with the bimorph that vibrates at the resonant frequency, while slow scanning is carried out by the tube scanner. The design and performance of the scanner is discussed and given in detailed. Combined with a commercially available data acquisition system, a high speed AFM has been built successfully. By real-time observing the deformation of the pores on the surface of a commercial piezoelectric lead zirconate titanate (PZT-5) ceramics under electric field, the dynamic imaging capability of the AFM is demonstrated. The results show that the notable advantage of the AFM is that dynamic process of the sample with large dimensions can be easily investigated. In addition, this design could provide a way to study a sample in real time under the given experimental condition, such as under an external electric field, on a heating stage, or in a liquid cell.

  8. Synthesis, characterization and electrochemical properties of α-MoO3 nanobelts for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Yayapao, Oranuch; Phuruangrat, Anukorn; Thongtem, Titipun; Thongtem, Somchai

    2016-06-01

    Orthorhombic molybdenum trioxide (α-MoO3) nanobelts have been successfully synthesized by hydrothermal method at 180°C for 20 h. The prepared α-MoO3 samples were investigated by X-ray diffraction, Fourier transform IR spectroscopy, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy methods. It was found that α-MoO3 nanobelts grow along the c-axis, with ±(100) top or bottom surfaces and ±(010) side surfaces. The prepared α-MoO3 nanobelts were used as cathode materials for Li-ion batteries. They exhibit specific capacity of 1340 and 1250 mA h g-1 at a current density of 100 and 400 mA/g, respectively.

  9. Real-time observation of morphological transformations in II-VI semiconducting nanobelts via environmental transmission electron microscopy

    SciTech Connect

    Agarwal, Rahul; Zakharov, Dmitri N.; Krook, Nadia M.; Liu, Wenjing; Berger, Jacob; Stach, Eric A.; Agarwal, Ritesh

    2015-05-01

    It has been observed that wurtzite II–VI semiconducting nanobelts transform into single-crystal, periodically branched nanostructures upon heating. The mechanism of this novel transformation has been elucidated by heating II–VI nanobelts in an environmental transmission electron microscope (ETEM) in oxidizing, reducing and inert atmospheres while observing their structural changes with high spatial resolution. The interplay of surface reconstruction of high-energy surfaces of the wurtzite phase and environment-dependent anisotropic chemical etching of certain crystal surfaces in the branching mechanism of nanobelts has been observed. Understanding of structural and chemical transformations of materials via in situ microscopy techniques and their role in designing new nanostructured materials is discussed.

  10. Real-time observation of morphological transformations in II-VI semiconducting nanobelts via environmental transmission electron microscopy

    DOE PAGES

    Agarwal, Rahul; Zakharov, Dmitri N.; Krook, Nadia M.; Liu, Wenjing; Berger, Jacob; Stach, Eric A.; Agarwal, Ritesh

    2015-05-01

    It has been observed that wurtzite II–VI semiconducting nanobelts transform into single-crystal, periodically branched nanostructures upon heating. The mechanism of this novel transformation has been elucidated by heating II–VI nanobelts in an environmental transmission electron microscope (ETEM) in oxidizing, reducing and inert atmospheres while observing their structural changes with high spatial resolution. The interplay of surface reconstruction of high-energy surfaces of the wurtzite phase and environment-dependent anisotropic chemical etching of certain crystal surfaces in the branching mechanism of nanobelts has been observed. Understanding of structural and chemical transformations of materials via in situ microscopy techniques and their role in designingmore » new nanostructured materials is discussed.« less

  11. Cable suspended windmill

    NASA Technical Reports Server (NTRS)

    Farmer, Moses G. (Inventor)

    1990-01-01

    A windmill is disclosed which includes an airframe having an upwind end and a downwind end. The first rotor is rotatably connected to the airframe, and a generator is supported by the airframe and driven by the rotor. The airframe is supported vertically in an elevated disposition by poles which extend vertically upwardly from the ground and support cables which extend between the vertical poles. Suspension cables suspend the airframe from the support cable.

  12. Development of in-series piezoelectric bimorph bending beam actuators for active flow control applications

    NASA Astrophysics Data System (ADS)

    Chan, Wilfred K.; Clingman, Dan J.; Amitay, Michael

    2016-04-01

    Piezoelectric materials have long been used for active flow control purposes in aerospace applications to increase the effectiveness of aerodynamic surfaces on aircraft, wind turbines, and more. Piezoelectric actuators are an appropriate choice due to their low mass, small dimensions, simplistic design, and frequency response. This investigation involves the development of piezoceramic-based actuators with two bimorphs placed in series. Here, the main desired characteristic was the achievable displacement amplitude at specific driving voltages and frequencies. A parametric study was performed, in which actuators with varying dimensions were fabricated and tested. These devices were actuated with a sinusoidal waveform, resulting in an oscillating platform on which to mount active flow control devices, such as dynamic vortex generators. The main quantification method consisted of driving these devices with different voltages and frequencies to determine their free displacement, blocking force, and frequency response. It was found that resonance frequency increased with shorter and thicker actuators, while free displacement increased with longer and thinner actuators. Integration of the devices into active flow control test modules is noted. In addition to physical testing, a quasi-static analytical model was developed and compared with experimental data, which showed close correlation for both free displacement and blocking force.

  13. Adaptive Q control for tapping-mode nanoscanning using a piezoactuated bimorph probe.

    PubMed

    Gunev, Ihsan; Varol, Aydin; Karaman, Sertac; Basdogan, Cagatay

    2007-04-01

    A new approach, called adaptive Q control, for tapping-mode atomic force microscopy (AFM) is introduced and implemented on a homemade AFM setup utilizing a laser Doppler vibrometer and a piezoactuated bimorph probe. In standard Q control, the effective Q factor of the scanning probe is adjusted prior to the scanning depending on the application. However, there is a trade-off in setting the effective Q factor of an AFM probe. The Q factor is either increased to reduce the tapping forces or decreased to increase the maximum achievable scan speed. Realizing these two benefits simultaneously using standard Q control is not possible. In adaptive Q control, the Q factor of the probe is set to an initial value as in standard Q control, but then modified on the fly during scanning when necessary to achieve this goal. In this article, we present the basic theory behind adaptive Q control, the electronics enabling the online modification of the probe's effective Q factor, and the results of the experiments comparing three different methods: scanning (a) without Q control, (b) with standard Q control, and (c) with adaptive Q control. The results show that the performance of adaptive Q control is superior to the other two methods.

  14. Impulse excitation of piezoelectric bimorphs for energy harvesting: a dimensionless model

    NASA Astrophysics Data System (ADS)

    Pozzi, Michele

    2014-04-01

    Energy harvesting (EH) is a multidisciplinary research area, involving physics, materials science and engineering, with the objective of providing renewable sources of power sufficient to operate targeted low-power applications. Piezoelectric transducers are often used for inertial vibrational as well as direct excitation EH. However, due to the stiffness of the most common material (PZT), compact and light-weight harvesters have high resonant frequencies, making them inefficient at extracting low-frequency power from the environment. The technique of frequency up-conversion, in the form of either plucking or impulse excitation, aims to bridge this frequency gap. In this paper, the technique is modelled analytically with focus on impulse excitation via impact or shock. An analytical model is developed in a standard way starting from the Euler-Bernoulli beam equations adapted to a piezoelectric bimorph. A set of dimensionless variables and parameters is defined and a system of differential equations derived. Here the system is solved numerically for a wide range of the two group parameters present, covering piezoelectric coupling strength between PVDF and PMN-PT. One major result is that the strength of the coupling strongly affects the timescale of the process, but has only a minor effect on the total energy converted. The model can be readily adapted to different excitation profiles.

  15. Analysis of the deformational behaviour of a bimorph configuration with piezoelectric actuation

    NASA Astrophysics Data System (ADS)

    Beckert, Wieland; Pfundtner, Goesta

    2002-08-01

    The stimulation of controlled deformation in lightweight constructions by means of actuator units as an integrated part of the structure currently represents an attractive subject in engineering. A common design uses a piezoelectric film that is bonded to a shell component by an adhesive layer and induces a bending deformation in the structure. A simplified beam design has been used as a test set-up to characterize the actuator performance of a given system under practical conditions. The bimorph configuration consists of an actuator unit, the bonding adhesive and the substrate material from which the lateral bending deflection of the free end, induced by actuation of the piezoelectric film, is measured. An improved theoretical approach is presented that combines a comprehensive composite theory analysis of the bending with a detailed analytical approach for the gradual stress transfer from the edges of the piezoceramic induced by a deformational misfit between the layers. The results are validated by a finite element analysis of the system. They reveal a substantial influence of the assumptions for the transverse (width direction) state of deformation for which free bending appears to be the most realistic for the test geometry. The study is completed by an experimental analysis that investigates the influence of adhesive stiffness and layer thickness on the actuator performance of a system consisting of a steel substrate and a carbon fibre reinforced substrate and a prototypic PZT actuator module. The results are correlated to the model providing a confirmation of the essential trends.

  16. Characterization of a bimorph deformable mirror using stroboscopic phase-shifting interferometry

    PubMed Central

    Horsley, David A.; Park, Hyunkyu; Laut, Sophie P.; Werner, John S.

    2008-01-01

    The static and dynamic characteristics of a bimorph deformable mirror (DM) for use in an adaptive optics system are described. The DM is a 35-actuator device composed of two disks of lead magnesium niobate (PMN), an electrostrictive ceramic that produces a mechanical strain in response to an imposed electric field. A custom stroboscopic phase-shifting interferometer was developed to measure the deformation of the mirror in response to applied voltage. The ability of the mirror to replicate optical aberrations described by the Zernike polynomials was tested as a measure of the mirror’s static performance. The natural frequencies of the DM were measured up to 20 kHz using both stroboscopic interferometry as well as a commercial laser Doppler vibrometer (LDV). Interferometric measurements of the DM surface profile were analyzed by fitting the surface with mode-shapes predicted using classical plate theory for an elastically supported disk. The measured natural frequencies were found to be in good agreement with the predictions of the theoretical model. PMID:19122798

  17. Photoinduced stiffening and photoplastic effect of ZnS individual nanobelt in nanoindentation

    SciTech Connect

    Zheng, X. J.; Yu, G. C.; Chen, Y. Q.; Mao, S. X.; Zhang, T.

    2010-11-15

    The photoinduced stiffening (PIS) and photoplastic effect (PPE) of ZnS individual nanobelt (NB) were observed by using a nanoindenter in conjunction with an incident ultraviolet (UV) light source system. The results show that the elastic modulus and hardness of ZnS individual NB under UV illumination are at least 32% and 20% larger than those in darkness. The mechanisms of PIS and PPE are interpreted by the increase in electronic strain and Peierls barrier due to the photogeneration of free carriers in ZnS individual NB. The research may offer useful guidelines to the application of optoelectronic devices based on individual nanostructures.

  18. Synthesis of mesoporous niobium nitride nanobelt arrays and their capacitive properties

    NASA Astrophysics Data System (ADS)

    Gao, Biao; Xiao, Xiang; Su, Jianjun; Zhang, Xuming; Peng, Xiang; Fu, Jijiang; Chu, Paul K.

    2016-10-01

    Mesoporous niobium nitride nanobelt arrays (Nb4N5 NBAs) are fabricated directly on Nb foils by a hydrothermal reaction in KOH, protonation treatment in HNO3, and calcination in an NH3 ambient. The morphology, composition and pore structure of the Nb4N5 NBAs are characterized in details. In addition, the mesoporous Nb4N5 NBAs electrode has good specific capacitance (37.4 mF cm-2, or 124 F g-1) and delivers excellent rate performance due to the high porosity and good electron conductivity boding well for application to next-generation energy storage systems.

  19. Large electrical manipulation of permittivity in BaTiO{sub 3} and Pb(Zr,Ti)O{sub 3} bimorph heterostructure

    SciTech Connect

    Ci, Penghong; Liu, Guoxi; Dong, Shuxiang; Zhang, Li

    2014-08-18

    We report a strain-mediated electric field manipulation of permittivity in BaTiO{sub 3} (barium titanate, BT) ceramic by a Pb(Zr,Ti)O{sub 3} (PZT) bimorph. This BT/PZT heterostructure exhibited a relatively large permittivity tunability of BT up to ±10% in a wide frequency range under an electric field of ±4 kV/cm applied to the PZT bimorph. The permittivity tunability is attributed to the strain in BT produced by the PZT bimorph. Calculations of the relationship between permittivity and applied electric field were developed, and corresponded well with measurements. The BT/PZT heterostructure has potential for applications in broadband field tunable smart electronic devices.

  20. Anatase TiO2 ultrathin nanobelts derived from room-temperature-synthesized titanates for fast and safe lithium storage

    PubMed Central

    Wen, Wei; Wu, Jin-ming; Jiang, Yin-zhu; Yu, Sheng-lan; Bai, Jun-qiang; Cao, Min-hua; Cui, Jie

    2015-01-01

    Lithium-ion batteries (LIBs) are promising energy storage devices for portable electronics, electric vehicles, and power-grid applications. It is highly desirable yet challenging to develop a simple and scalable method for constructions of sustainable materials for fast and safe LIBs. Herein, we exploit a novel and scalable route to synthesize ultrathin nanobelts of anatase TiO2, which is resource abundant and is eligible for safe anodes in LIBs. The achieved ultrathin nanobelts demonstrate outstanding performances for lithium storage because of the unique nanoarchitecture and appropriate composition. Unlike conventional alkali-hydrothermal approaches to hydrogen titanates, the present room temperature alkaline-free wet chemistry strategy guarantees the ultrathin thickness for the resultant titanate nanobelts. The anatase TiO2 ultrathin nanobelts were achieved simply by a subsequent calcination in air. The synthesis route is convenient for metal decoration and also for fabricating thin films of one/three dimensional arrays on various substrates at low temperatures, in absence of any seed layers. PMID:26133276

  1. Anatase TiO2 ultrathin nanobelts derived from room-temperature-synthesized titanates for fast and safe lithium storage

    NASA Astrophysics Data System (ADS)

    Wen, Wei; Wu, Jin-Ming; Jiang, Yin-Zhu; Yu, Sheng-Lan; Bai, Jun-Qiang; Cao, Min-Hua; Cui, Jie

    2015-07-01

    Lithium-ion batteries (LIBs) are promising energy storage devices for portable electronics, electric vehicles, and power-grid applications. It is highly desirable yet challenging to develop a simple and scalable method for constructions of sustainable materials for fast and safe LIBs. Herein, we exploit a novel and scalable route to synthesize ultrathin nanobelts of anatase TiO2, which is resource abundant and is eligible for safe anodes in LIBs. The achieved ultrathin nanobelts demonstrate outstanding performances for lithium storage because of the unique nanoarchitecture and appropriate composition. Unlike conventional alkali-hydrothermal approaches to hydrogen titanates, the present room temperature alkaline-free wet chemistry strategy guarantees the ultrathin thickness for the resultant titanate nanobelts. The anatase TiO2 ultrathin nanobelts were achieved simply by a subsequent calcination in air. The synthesis route is convenient for metal decoration and also for fabricating thin films of one/three dimensional arrays on various substrates at low temperatures, in absence of any seed layers.

  2. Anatase TiO2 ultrathin nanobelts derived from room-temperature-synthesized titanates for fast and safe lithium storage.

    PubMed

    Wen, Wei; Wu, Jin-ming; Jiang, Yin-zhu; Yu, Sheng-lan; Bai, Jun-qiang; Cao, Min-hua; Cui, Jie

    2015-01-01

    Lithium-ion batteries (LIBs) are promising energy storage devices for portable electronics, electric vehicles, and power-grid applications. It is highly desirable yet challenging to develop a simple and scalable method for constructions of sustainable materials for fast and safe LIBs. Herein, we exploit a novel and scalable route to synthesize ultrathin nanobelts of anatase TiO2, which is resource abundant and is eligible for safe anodes in LIBs. The achieved ultrathin nanobelts demonstrate outstanding performances for lithium storage because of the unique nanoarchitecture and appropriate composition. Unlike conventional alkali-hydrothermal approaches to hydrogen titanates, the present room temperature alkaline-free wet chemistry strategy guarantees the ultrathin thickness for the resultant titanate nanobelts. The anatase TiO2 ultrathin nanobelts were achieved simply by a subsequent calcination in air. The synthesis route is convenient for metal decoration and also for fabricating thin films of one/three dimensional arrays on various substrates at low temperatures, in absence of any seed layers. PMID:26133276

  3. Anatase TiO2 ultrathin nanobelts derived from room-temperature-synthesized titanates for fast and safe lithium storage.

    PubMed

    Wen, Wei; Wu, Jin-ming; Jiang, Yin-zhu; Yu, Sheng-lan; Bai, Jun-qiang; Cao, Min-hua; Cui, Jie

    2015-07-02

    Lithium-ion batteries (LIBs) are promising energy storage devices for portable electronics, electric vehicles, and power-grid applications. It is highly desirable yet challenging to develop a simple and scalable method for constructions of sustainable materials for fast and safe LIBs. Herein, we exploit a novel and scalable route to synthesize ultrathin nanobelts of anatase TiO2, which is resource abundant and is eligible for safe anodes in LIBs. The achieved ultrathin nanobelts demonstrate outstanding performances for lithium storage because of the unique nanoarchitecture and appropriate composition. Unlike conventional alkali-hydrothermal approaches to hydrogen titanates, the present room temperature alkaline-free wet chemistry strategy guarantees the ultrathin thickness for the resultant titanate nanobelts. The anatase TiO2 ultrathin nanobelts were achieved simply by a subsequent calcination in air. The synthesis route is convenient for metal decoration and also for fabricating thin films of one/three dimensional arrays on various substrates at low temperatures, in absence of any seed layers.

  4. Sodium manganese oxide nanobelts with a 2 x 4 tunnel structure: one-step hydrothermal synthesis and electrocatalytic properties.

    PubMed

    Zhang, Xiong; Yang, Wensheng; Chen, Xu; Ma, Yanwei

    2009-10-01

    Sodium manganese oxide nanobelts with a 2 x 4 tunnel structure (Na-2 x 4) have been one-step hydrothermally synthesized at 200 degrees C for a relatively short time (16 h). The products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The Na-2 x 4 tunnel manganese oxide nanobelts have the thickness of about 20 nm, the width with ranges from 50 to 200 nm and the length up to several micrometers. The synthetic temperature is critical to the crystal structure of the final products and Na-birnessite is obtained at 120 degrees C. The electrocatalytic activities of the above products are studied for oxygen reduction reaction in aqueous basic medium. The Na-2 x 4 tunnel manganese oxide nanobelts exhibit higher oxygen reduction activity (12.8 mA cm(-2) or 9.09 A g(-1)) than that of Na-birnessite (5.6 mA cm(-2) or 3.98 A g(-1)) at -0.44 V. The Na-2 x 4 tunnel manganese oxide nanobelts could be potentially used as air electrode materials for catalytic reduction of O2 in alkaline fuel cells and metal/air batteries. PMID:19908465

  5. One-step hydrothermal synthesis of graphene decorated V2O5 nanobelts for enhanced electrochemical energy storage

    PubMed Central

    Lee, Minoh; Balasingam, Suresh Kannan; Jeong, Hu Young; Hong, Won G.; Lee, Han-Bo-Ram; Kim, Byung Hoon; Jun, Yongseok

    2015-01-01

    Graphene-decorated V2O5 nanobelts (GVNBs) were synthesized via a low-temperature hydrothermal method in a single step. V2O5 nanobelts (VNBs) were formed in the presence of graphene oxide, a mild oxidant, which also enhanced the conductivity of GVNBs. From the electron energy loss spectroscopy analysis, the reduced graphene oxide (rGO) are inserted into the layered crystal structure of V2O5 nanobelts, which further confirmed the enhanced conductivity of the nanobelts. The electrochemical energy-storage capacity of GVNBs was investigated for supercapacitor applications. The specific capacitance of GVNBs was evaluated using cyclic voltammetry (CV) and charge/discharge (CD) studies. The GVNBs having V2O5-rich composite, namely, V3G1 (VO/GO = 3:1), showed superior specific capacitance in comparison to the other composites (V1G1 and V1G3) and the pure materials. Moreover, the V3G1 composite showed excellent cyclic stability and the capacitance retention of about 82% was observed even after 5000 cycles. PMID:25633147

  6. Cu and CuO/titanate nanobelt based network assemblies for enhanced visible light photocatalysis.

    PubMed

    Logar, Manca; Bračko, Ines; Potočnik, Anton; Jančar, Boštjan

    2014-04-29

    3D network configurations of copper(II) oxide/titanate nanobelt (CuO/TiNBs) and copper/titanate nanobelt (Cu/TiNBs) were formed using a two-step polyelectrolyte-assisted synthesis and assembly approach. The photoactivity of the TiNB/CuO and Cu/TiNB composite networks is significantly enhanced as compared to the activity of 3D structures formed of pristine TiNB. An efficient, UV-vis-light-induced electron transfer at the two-component interface achieved by the intimate coupling of TiNB with p-type semiconducting CuO and plasmonic Cu nanoparticles in composite heterostructures facilitates control over the system's exciton dynamics, which results in highly efficient UV-vis photocatalytic performance of heterostructures. The superior photocatalytic activity of the metal and semiconductor/semiconductor nanocomposite structures in the visible region is discussed, highlighting the role of interfacial electron-charge transfer (IFCT) in semiconductor-semiconductor (CuO/TiNB) and surface plasmon resonance (SPR) of Cu nanoparticles in metal-semiconductor heterostructures. PMID:24697758

  7. Local defect-induced red-shift of cathodoluminescence in individual ZnS nanobelts.

    PubMed

    Liu, B D; Yang, B; Dierre, B; Sekiguchi, T; Jiang, X

    2014-11-01

    The luminescence of semiconductor nanostructures is strongly dependent on their size, dimensions, morphology, composition, or defects, and their band emissions can be properly and selectively tailored through the rational manipulation of these parameters during material growth. Using spatially-resolved cathodoluminescence spectroscopy, monochromatic contrast maps and high-resolution transmission electron microscopy, an obvious red-shift of the near-band-edge emission of wurtzite ZnS nanobelts, resulting from a strip of stacking faults or a zinc-blende phase with tens of atomic layers in width, has been observed and its related mechanism has been discussed. This finding is not specific to the defect-dependent optical properties tailoring of ZnS nanostructures and represents a general validity for clarifying the mechanism of peak-shift (band-gap expansion or shrinking) of a wide range of semiconductor nanostructures with various defects. In addition, the general formation mechanism of the belt-like nanostructure was proposed based on precise microstructure analyses on a ZnS nanobelt with atomic terrace growth fronts.

  8. A Single Nanobelt Transistor for Gas Identification: Using a Gas-Dielectric Strategy.

    PubMed

    Cai, Bin; Song, Zhiqi; Tong, Yanhong; Tang, Qingxin; Shaymurat, Talgar; Liu, Yichun

    2016-06-21

    Despite tremendous potential and urgent demand in high-response low-cost gas identification, the development of gas identification based on a metal oxide semiconductor nanowire/nanobelt remains limited by fabrication complexity and redundant signals. Researchers have shown a multisensor-array strategy with "one key to one lock" configuration. Here, we describe a new strategy to create high-response room-temperature gas identification by employing gas as dielectric. This enables gas discrimination down to the part per billion (ppb) level only based on one pristine single nanobelt transistor, with the excellent average Mahalanobis distance (MD) as high as 35 at the linear discriminant analysis (LDA) space. The single device realizes the selective recognition function of electronic nose. The effect of the gas dielectric on the response of the multiple field-effect parameters is discussed by the comparative investigation of gas and solid-dielectric devices and the studies on trap density changes in the conductive channel. The current work opens up exciting opportunities for room-temperature gas recognition based on the pristine single device.

  9. A Single Nanobelt Transistor for Gas Identification: Using a Gas-Dielectric Strategy

    PubMed Central

    Cai, Bin; Song, Zhiqi; Tong, Yanhong; Tang, Qingxin; Shaymurat, Talgar; Liu, Yichun

    2016-01-01

    Despite tremendous potential and urgent demand in high-response low-cost gas identification, the development of gas identification based on a metal oxide semiconductor nanowire/nanobelt remains limited by fabrication complexity and redundant signals. Researchers have shown a multisensor-array strategy with “one key to one lock” configuration. Here, we describe a new strategy to create high-response room-temperature gas identification by employing gas as dielectric. This enables gas discrimination down to the part per billion (ppb) level only based on one pristine single nanobelt transistor, with the excellent average Mahalanobis distance (MD) as high as 35 at the linear discriminant analysis (LDA) space. The single device realizes the selective recognition function of electronic nose. The effect of the gas dielectric on the response of the multiple field-effect parameters is discussed by the comparative investigation of gas and solid-dielectric devices and the studies on trap density changes in the conductive channel. The current work opens up exciting opportunities for room-temperature gas recognition based on the pristine single device. PMID:27338394

  10. A Single Nanobelt Transistor for Gas Identification: Using a Gas-Dielectric Strategy.

    PubMed

    Cai, Bin; Song, Zhiqi; Tong, Yanhong; Tang, Qingxin; Shaymurat, Talgar; Liu, Yichun

    2016-01-01

    Despite tremendous potential and urgent demand in high-response low-cost gas identification, the development of gas identification based on a metal oxide semiconductor nanowire/nanobelt remains limited by fabrication complexity and redundant signals. Researchers have shown a multisensor-array strategy with "one key to one lock" configuration. Here, we describe a new strategy to create high-response room-temperature gas identification by employing gas as dielectric. This enables gas discrimination down to the part per billion (ppb) level only based on one pristine single nanobelt transistor, with the excellent average Mahalanobis distance (MD) as high as 35 at the linear discriminant analysis (LDA) space. The single device realizes the selective recognition function of electronic nose. The effect of the gas dielectric on the response of the multiple field-effect parameters is discussed by the comparative investigation of gas and solid-dielectric devices and the studies on trap density changes in the conductive channel. The current work opens up exciting opportunities for room-temperature gas recognition based on the pristine single device. PMID:27338394

  11. PLD-assisted VLS growth of aligned ferrite nanorods, nanowires, and nanobelts-synthesis, and properties.

    PubMed

    Morber, Jenny Ruth; Ding, Yong; Haluska, Michael Stephan; Li, Yang; Liu, J Ping; Wang, Zhong Lin; Snyder, Robert L

    2006-11-01

    We report here a systematic synthesis and characterization of aligned alpha-Fe2O3 (hematite), epsilon-Fe2O3, and Fe3O4 (magnetite) nanorods, nanobelts, and nanowires on alumina substrates using a pulsed laser deposition (PLD) method. The presence of spherical gold catalyst particles at the tips of the nanostructures indicates selective growth via the vapor-liquid-solid (VLS) mechanism. Through a series of experiments, we have produced a primitive "phase diagram" for growing these structures based on several designed pressure and temperature parameters. Transmission electron microscopy (TEM) analysis has shown that the rods, wires, and belts are single-crystalline and grow along <111>m or <110>h directions. X-ray diffraction (XRD) measurements confirm phase and structural analysis. Superconducting quantum interference device (SQUID) measurements show that the iron oxide structures exhibit interesting magnetic behavior, particularly at room temperature. This work is the first known report of magnetite 1D nanostructure growth via the vapor-liquid-solid (VLS) mechanism without using a template, as well as the first known synthesis of long epsilon-Fe2O3 nanobelts and nanowires. PMID:17064124

  12. Annealing effects on the structural and optical properties of β-Ga2O3 nanobelts synthesized by microwave plasma chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Zhu, Feng; Yang, ZhongXue; Zhou, WeiMin; Zhang, YaFei

    2006-06-01

    We have synthesized β-Ga2O3 nanobelts on the silicon substrates by microwave plasma chemical vapor deposition (MPCVD). The morphology and structure of β-Ga2O3 nanobelts characterized by scanning electron microscopy (SEM) were not influenced through the thermal annealing. The photoluminescence properties of β-Ga2O3 nanobelts measured under different excitation wavelength, annealing temperature and annealing time indicated that as-prepared and annealed nanobelts had a blue and an ultraviolet emission (under excitation wavelength of 250 nm at 316 and 432 nm, under excitation wavelength of 325 at 428 nm), but the relative peak intensities of ultraviolet and blue emission, respectively, increase and decrease by the thermal annealing.

  13. Electroelastic modeling and experimental validations of piezoelectric energy harvesting from broadband random vibrations of cantilevered bimorphs

    NASA Astrophysics Data System (ADS)

    Zhao, S.; Erturk, A.

    2013-01-01

    We present electroelastic modeling, analytical and numerical solutions, and experimental validations of piezoelectric energy harvesting from broadband random vibrations. The modeling approach employed herein is based on a distributed-parameter electroelastic formulation to ensure that the effects of higher vibration modes are included, since broadband random vibrations, such as Gaussian white noise, might excite higher vibration modes. The goal is to predict the expected value of the power output and the mean-square shunted vibration response in terms of the given power spectral density (PSD) or time history of the random vibrational input. The analytical method is based on the PSD of random base excitation and distributed-parameter frequency response functions of the coupled voltage output and shunted vibration response. The first of the two numerical solution methods employs the Fourier series representation of the base acceleration history in an ordinary differential equation solver while the second method uses an Euler-Maruyama scheme to directly solve the resulting electroelastic stochastic differential equations. The analytical and numerical simulations are compared with several experiments for a brass-reinforced PZT-5H bimorph under different random excitation levels. The simulations exhibit very good agreement with the experimental measurements for a range of resistive electrical boundary conditions and input PSD levels. It is also shown that lightly damped higher vibration modes can alter the expected power curve under broadband random excitation. Therefore, the distributed-parameter modeling and solutions presented herein can be used as a more accurate alternative to the existing single-degree-of-freedom solutions for broadband random vibration energy harvesting.

  14. A soft-polymer piezoelectric bimorph cantilever-actuated peristaltic micropump.

    PubMed

    Graf, Neil J; Bowser, Michael T

    2008-10-01

    A peristaltic micropump was fabricated and characterized. The micropump was fabricated using soft lithography, and actuated using piezoelectric bimorph cantilevers. The micropump channel was formed by bonding two layers of PDMS, mixed at 5:1 and 30:1 ratios. The channel was fabricated in the 5:1 layer using replica molding (REM), where a very simple and inexpensive template was made by straddling a 75 microm wire over a glass substrate, followed by covering and smoothing over the wire with a piece of aluminium foil. Not only was this template inexpensive and extremely simple to fabricate, it also created a rounded cross-sectional geometry which is favorable for complete valve shutoff. The cantilevers were driven at Vp=+/-90 V with amplified square wave signals generated by a virtual function generator created in LabVIEW. Connections to the micropump were made by placing capillary tubes in the channel, and then sealed between the two layers of PDMS. Machined aluminium clamps were adhered to the tips of the cantilevers with general purpose adhesive. These clamps allowed for aluminium valves, with finely machined tips of dimensions 3 mm by 200 microm, to be held firmly in place. The variables characterized for this micropump were flow rate, maximum attainable backpressure, free cantilever deflection, valve shutoff, and valve leakage. Three actuation patterns with phase differences of 60, 90, and 120 degrees were compared for flow rate and maximum backpressure. It was determined that the 120 degrees signal outperformed the 60 degrees and 90 degrees signals for both maximum flowrate and maximum attainable backpressure. The maximum and minimum flowrates demonstrated by the micropump were 289 nL min(-1) and 53 nL min(-1), respectively. The maximum backpressure attained was 35 300 Pa. It was also demonstrated that the valves fully closed the channels upon actuation, with minimal observed leakage.

  15. Dispersive suspended microextraction.

    PubMed

    Yang, Zhong-Hua; Liu, Yu; Lu, Yue-Le; Wu, Tong; Zhou, Zhi-Qiang; Liu, Dong-Hui

    2011-11-14

    A novel sample pre-treatment technique termed dispersive suspended microextraction (DSME) coupled with gas chromatography-flame photometric detection (GC-FPD) has been developed for the determination of eight organophosphorus pesticides (ethoprophos, malathion, chlorpyrifos, isocarbophos, methidathion, fenamiphos, profenofos, triazophos) in aqueous samples. In this method, both extraction and two phases' separation process were performed by the assistance of magnetic stirring. After separating the two phases, 1 μL of the suspended phase was injected into GC for further instrument analysis. Varieties of experiment factors which could affect the experiment results were optimized and the following were selected: 12.0 μL p-xylene was selected as extraction solvent, extraction speed was 1200 rpm, extraction time was 30 s, the restoration speed was 800 rpm, the restoration time was 8 min, and no salt was added. Under the optimum conditions, limits of detections (LODs) varied between 0.01 and 0.05 μg L(-1). The relative standard deviation (RSDs, n=6) ranged from 4.6% to 12.1%. The linearity was obtained by five points in the concentration range of 0.1-100.0 μg L(-1). Correlation coefficients (r) varied from 0.9964 to 0.9995. The enrichment factors (EFs) were between 206 and 243. In the final experiment, the developed method has been successfully applied to the determination of organophosphorus pesticides in wine and tap water samples and the obtained recoveries were between 83.8% and 101.3%. Compared with other pre-treatment methods, DSME has its own features and could achieve satisfied results for the analysis of trace components in complicated matrices. PMID:22023861

  16. Shear force near-field optical microscope based on Q-controlled bimorph sensor for biological imaging in liquid.

    PubMed

    Lei, F H; Angiboust, J-F; Qiao, W; Sockalingum, G D; Dukic, S; Chrit, L; Troyon, M; Manfait, M

    2004-12-01

    Shear force near-field microscopy on biological samples in their physiological environment loses considerable sensitivity and resolution as a result of liquid viscous damping. Using a bimorph-based cantilever sensor incorporating force feedback, as recently developed by us, gives an alternative force detection scheme for biological imaging in liquid. The dynamics and sensitivity of this sensor were theoretically and experimentally discussed. Driving the bimorph cantilever close to its resonance frequency with appropriate force feedback allows us to obtain a quality factor (Q-factor) of up to 10(3) in water, without changing its intrinsic resonance frequency and spring constant. Thus, the force detection sensitivity is improved. Shear force imaging on mouse brain sections and human skin tissues in liquid with an enhanced Q-factor of 410 have shown a high sensitivity and stability. A resolution of about 50 nm has been obtained. The experimental results suggest that the system is reliable and particularly suitable for biological cell imaging in a liquid environment. PMID:15566494

  17. Fabrication of a self-sensing electroactive polymer bimorph actuator based on polyvinylidene fluoride and its electrostrictive terpolymer

    NASA Astrophysics Data System (ADS)

    Engel, Leeya; Van Volkinburg, Kyle R.; Ben-David, Moti; Washington, Gregory N.; Krylov, Slava; Shacham-Diamand, Yosi

    2016-04-01

    In this paper, we report on the fabrication of a self-sensing electroactive polymer cantilevered bimorph beam actuator and its frequency response. Tip deflections of the beam, induced by applying an AC signal across ferroelectric relaxor polyvinylidene fluoride-trifluoroethylene chlorotrifluoroethylene (P(VDF-TrFE-CTFE)), reached a magnitude of 350μm under a field of ~55MV/m and were recorded externally using a laser Doppler vibrometer (LDV). Deflections were determined simultaneously by applying a sensing model to the voltage measured across the bimorph's integrated layer of piezoelectric polymer polyvinylidene fluoride (PVDF). The sensing model treats the structure as a simple Euler- Bernoulli cantilevered beam with two distributed active elements represented through the use of generalized functions and offers a method through which real time tip deflection can be measured without the need for external visualization. When not being used as a sensing element, the PVDF layer can provide an additional means for actuation of the beam via the converse piezoelectric effect, resulting in bidirectional control of the beam's deflections. Integration of flexible sensing elements together with modeling of the electroactive polymer beam can benefit the developing field of polymer microactuators which have applications in soft robotics as "smart" prosthetics/implants, haptic displays, tools for less invasive surgery, and sensing.

  18. Energy Harvesting Characteristics from Water Flow by Piezoelectric Energy Harvester Device Using Cr/Nb Doped Pb(Zr,Ti)O3 Bimorph Cantilever

    NASA Astrophysics Data System (ADS)

    Kim, Kyoung-Bum; Kim, Chang Il; Jeong, Young Hun; Cho, Jeong-Ho; Paik, Jong-Hoo; Nahm, Sahn; Lim, Jong Bong; Seong, Tae-Hyeon

    2013-10-01

    A water flow energy harvester, which can convert water flow energy to electric energy, was fabricated for its application to rivers. This harvester can generate power from the bending and releasing motion of piezoelectric bimorph cantilevers. A Pb(Zr0.54Ti0.46)O3 + 0.2 wt % Cr2O3 + 1.0 wt % Nb2O5 (PZT-CN) thick film and a 250-µm-thick stainless steel were used as a bimorph cantilever. The electrical impedance matching was achieved across a resistive load of 1 kΩ. Four bimorph cantilevers can generate power from 5 to 105 rpm. The output powers were steadily increased by increasing the rpm. The maximum output power was 68 mW by 105 rpm. It was found that the water flow energy harvester can generate 58 mW by a flow velocity of (2 m/s) from the stream with the four bimorph cantilevers.

  19. Self-assembly of ultrathin Cu2MoS4 nanobelts for highly efficient visible light-driven degradation of methyl orange

    NASA Astrophysics Data System (ADS)

    Zhang, Ke; Chen, Wenxing; Lin, Yunxiang; Chen, Haiping; Haleem, Yasir A.; Wu, Chuanqiang; Ye, Fei; Wang, Tianxing; Song, Li

    2015-10-01

    We demonstrate ultrathin self-assembled Cu2MoS4 nanobelts synthesized by using Cu2O as the starting sacrificial template via a hydrothermal method. The nanobelts exhibit strong light absorption over a broad wavelength spectrum, suggesting their potential application as photocatalysts. The photocatalytic activity of nanobelts is evaluated by the degradation of Methyl Orange (MO) dye under visible light irradiation. Notably, the nanobelts can completely degrade 100 mL of 15 mg mL-1 MO in 20 minutes with excellent recycling and structural stability, suggesting their excellent photocatalytic performance. In comparison with a sheet-like sample, the high efficiency of the self-assembled Cu2MoS4 nanobelts is attributed to a high surface area and a unique band gap, agreeing with the nitrogen adsorption analysis and photoluminescence spectra. This study offers a self-assembled synthetic route to create new multifunctional nanoarchitectures composed of atomic layers, and thus may open a window for greatly extending potential applications in water pollution treatment, photocatalytic water-splitting, solar cells and other related fields.We demonstrate ultrathin self-assembled Cu2MoS4 nanobelts synthesized by using Cu2O as the starting sacrificial template via a hydrothermal method. The nanobelts exhibit strong light absorption over a broad wavelength spectrum, suggesting their potential application as photocatalysts. The photocatalytic activity of nanobelts is evaluated by the degradation of Methyl Orange (MO) dye under visible light irradiation. Notably, the nanobelts can completely degrade 100 mL of 15 mg mL-1 MO in 20 minutes with excellent recycling and structural stability, suggesting their excellent photocatalytic performance. In comparison with a sheet-like sample, the high efficiency of the self-assembled Cu2MoS4 nanobelts is attributed to a high surface area and a unique band gap, agreeing with the nitrogen adsorption analysis and photoluminescence spectra. This study

  20. Electrochemical sensing of bisphenol using a multilayer graphene nanobelt modified photolithography patterned platinum electrode.

    PubMed

    Kannan, Padmanathan Karthick; Hu, Chunxiao; Morgan, Hywel; Moshkalev, Stanislav A; Rout, Chandra Sekhar

    2016-09-16

    An electrochemical sensor has been developed for the detection of Bisphenol-A (BPA) using photolithographically patterned platinum electrodes modified with multilayer graphene nanobelts (GNB). Compared to bare electrodes, the GNB modified electrode exhibited enhanced BPA oxidation current, due to the high effective surface area and high adsorption capacity of the GNB. The sensor showed a linear response over the concentration range from 0.5 μM-9 μM with a very low limit of detection = 37.33 nM. In addition, the sensor showed very good stability and reproducibility with good specificity, demonstrating that GNB is potentially a new material for the development of a practical BPA electrochemical sensor with application in both industrial and plastic industries.

  1. Electrochemical sensing of bisphenol using a multilayer graphene nanobelt modified photolithography patterned platinum electrode

    NASA Astrophysics Data System (ADS)

    Karthick Kannan, Padmanathan; Hu, Chunxiao; Morgan, Hywel; Moshkalev, Stanislav A.; Sekhar Rout, Chandra

    2016-09-01

    An electrochemical sensor has been developed for the detection of Bisphenol-A (BPA) using photolithographically patterned platinum electrodes modified with multilayer graphene nanobelts (GNB). Compared to bare electrodes, the GNB modified electrode exhibited enhanced BPA oxidation current, due to the high effective surface area and high adsorption capacity of the GNB. The sensor showed a linear response over the concentration range from 0.5 μM-9 μM with a very low limit of detection = 37.33 nM. In addition, the sensor showed very good stability and reproducibility with good specificity, demonstrating that GNB is potentially a new material for the development of a practical BPA electrochemical sensor with application in both industrial and plastic industries.

  2. Lattice Breathing Inhibited Layered Vanadium Oxide Ultrathin Nanobelts for Enhanced Sodium Storage.

    PubMed

    Wei, Qiulong; Jiang, Zhouyang; Tan, Shuangshuang; Li, Qidong; Huang, Lei; Yan, Mengyu; Zhou, Liang; An, Qinyou; Mai, Liqiang

    2015-08-26

    Operating as the "rocking-chair" battery, sodium ion battery (SIB) with acceptable high capacity is a very promising energy storage technology. Layered vanadium oxide xerogel exhibits high sodium storage capacity. But it undergoes large lattice breathing during sodiation/desodiation, resulting in fast capacity fading. Herein, we develop a facile hydrothermal method to synthesize iron preintercalated vanadium oxide ultrathin nanobelts (Fe-VOx) with constricted interlayer spacing. Using the Fe-VOx as cathode for SIB, the lattice breathing during sodiation/desodiation is largely inhibited and the interlayer spacing is stabilized for reversible and rapid Na(+) insertion/extraction, displaying enhanced cycling and rate performance. This work presents a new strategy to reduce the lattice breathing of layered materials for enhanced sodium storage through interlayer spacing engineering.

  3. Electrochemical sensing of bisphenol using a multilayer graphene nanobelt modified photolithography patterned platinum electrode.

    PubMed

    Kannan, Padmanathan Karthick; Hu, Chunxiao; Morgan, Hywel; Moshkalev, Stanislav A; Rout, Chandra Sekhar

    2016-09-16

    An electrochemical sensor has been developed for the detection of Bisphenol-A (BPA) using photolithographically patterned platinum electrodes modified with multilayer graphene nanobelts (GNB). Compared to bare electrodes, the GNB modified electrode exhibited enhanced BPA oxidation current, due to the high effective surface area and high adsorption capacity of the GNB. The sensor showed a linear response over the concentration range from 0.5 μM-9 μM with a very low limit of detection = 37.33 nM. In addition, the sensor showed very good stability and reproducibility with good specificity, demonstrating that GNB is potentially a new material for the development of a practical BPA electrochemical sensor with application in both industrial and plastic industries. PMID:27504686

  4. Electrochemical sensing of bisphenol using a multilayer graphene nanobelt modified photolithography patterned platinum electrode

    NASA Astrophysics Data System (ADS)

    Karthick Kannan, Padmanathan; Hu, Chunxiao; Morgan, Hywel; Moshkalev, Stanislav A.; Sekhar Rout, Chandra

    2016-09-01

    An electrochemical sensor has been developed for the detection of Bisphenol-A (BPA) using photolithographically patterned platinum electrodes modified with multilayer graphene nanobelts (GNB). Compared to bare electrodes, the GNB modified electrode exhibited enhanced BPA oxidation current, due to the high effective surface area and high adsorption capacity of the GNB. The sensor showed a linear response over the concentration range from 0.5 μM–9 μM with a very low limit of detection = 37.33 nM. In addition, the sensor showed very good stability and reproducibility with good specificity, demonstrating that GNB is potentially a new material for the development of a practical BPA electrochemical sensor with application in both industrial and plastic industries.

  5. Present perspectives of broadband photodetectors based on nanobelts, nanoribbons, nanosheets and the emerging 2D materials.

    PubMed

    Dhanabalan, Sathish Chander; Ponraj, Joice Sophia; Zhang, Han; Bao, Qiaoliang

    2016-03-28

    Recent research on photodetectors has been mainly focused on nanostructured materials that form the building blocks of device fabrication. The selection of a suitable material with well-defined properties forms the key issue for the fabrication of photodetectors that cover different ranges of the electromagnetic spectrum. In this review, the latest progress in light detection using nanobelts, nanoribbons, nanosheets and the emerging two-dimensional (2D) materials is reviewed. Particular emphasis is placed on the detection of light by the hybrid structures of the mentioned nanostructured materials in order to enhance the efficiency of the light-matter interaction. The booming research area of black phosphorus based photo-detection is also reviewed. This review provides an overview of basic concepts and new directions towards photodetectors, and highlights potential for the future development of high performance broadband photodetectors. PMID:26935809

  6. Highly sensitive and selective electrochemical dopamine sensing properties of multilayer graphene nanobelts

    NASA Astrophysics Data System (ADS)

    Karthick Kannan, Padmanathan; Moshkalev, Stanislav A.; Sekhar Rout, Chandra

    2016-02-01

    In the present study, we report the electrochemical sensing property of multi-layer graphene nanobelts (GNBs) towards dopamine (DA). GNBs are synthesized from natural graphite and characterized by using techniques like field-emission scanning electron microscopy, atomic force microscopy and Raman spectroscopy. An electrochemical sensor based on GNBs is developed for the detection of DA. From the cyclic voltammetry and amperometry studies, it is found that GNBs possess excellent electrocatalytic activity towards DA molecules. The developed DA sensor showed a sensitivity value of 0.95 μA μM-1 cm-2 with a linear range of 2 μM to 0.2 mM. The interference data exhibited that GNB is highly selective to DA even in the presence of common interfering species like ascorbic acid, uric acid, glucose and lactic acid.

  7. Nanotubes, nanobelts, nanowires, and nanorods of silicon carbide from the wheat husks

    SciTech Connect

    Qadri, S. B.; Rath, B. B.; Gorzkowski, E. P.; Feng, J.; Qadri, S. N.; Caldwell, J. D.

    2015-09-14

    Nanotubes, nanowires, nanobelts, and nanorods of SiC were synthesized from the thermal treatment of wheat husks at temperatures in excess of 1450 °C. From the analysis based on x-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy, it has been found that the processed samples of wheat husk consisted of 2H and 3C polytypes of SiC exhibiting the nanostructure shapes. These nanostructures of silicon carbide formed from wheat husks are of technological importance for designing advance composites, applications in biotechnology, and electro-optics. The thermodynamics of the formation of SiC is discussed in terms of the rapid solid state reaction between hydrocarbons and silica on the molecular scale, which is inherently present in the wheat husks.

  8. Present perspectives of broadband photodetectors based on nanobelts, nanoribbons, nanosheets and the emerging 2D materials.

    PubMed

    Dhanabalan, Sathish Chander; Ponraj, Joice Sophia; Zhang, Han; Bao, Qiaoliang

    2016-03-28

    Recent research on photodetectors has been mainly focused on nanostructured materials that form the building blocks of device fabrication. The selection of a suitable material with well-defined properties forms the key issue for the fabrication of photodetectors that cover different ranges of the electromagnetic spectrum. In this review, the latest progress in light detection using nanobelts, nanoribbons, nanosheets and the emerging two-dimensional (2D) materials is reviewed. Particular emphasis is placed on the detection of light by the hybrid structures of the mentioned nanostructured materials in order to enhance the efficiency of the light-matter interaction. The booming research area of black phosphorus based photo-detection is also reviewed. This review provides an overview of basic concepts and new directions towards photodetectors, and highlights potential for the future development of high performance broadband photodetectors.

  9. Differential Mouse Pulmonary Dose and Time Course Responses to Titanium Dioxide Nanospheres and Nanobelts

    PubMed Central

    Porter, Dale W.

    2013-01-01

    Three anatase titanium dioxide (TiO2) nanoparticles (NPs) were prepared; nanospheres (NSs), short nanobelts (NB1), and long nanobelts (NB2). These NPs were used to investigate the effect of NP shape and length on lung toxicity. Mice were exposed (0–30 µg per mouse) by pharyngeal aspiration and pulmonary toxicity was assessed over a 112-day time course. Whole lung lavage data indicated that NB1- and NB2-exposed mice, but not NS-exposed mice, had significant dose- and time-dependent pulmonary inflammation and damage. Histopathological analyses at 112 days postexposure determined no interstitial fibrosis in any NS-exposed mice, an increased incidence in 30 µg NB1-exposed mice, and significant interstitial fibrosis in 30 µg NB2-exposed mice. At 112 days postexposure, lung burden of NS was decreased by 96.4% and NB2 by 80.5% from initial deposition levels. At 112 days postexposure, enhanced dark field microscopy determined that alveolar macro- phages were the dominant deposition site, but a fraction of NB1 and NB2 was observed in the alveolar interstitial spaces. For the 30 µg exposure groups at 112 days postexposure, confocal micro- scopy and immunofluorescent staining demonstrated that retained NB2 but not NS were present in the interstitium subjacent to the terminal bronchiole near the normal location of the smallest lymphatic capillaries in the lung. These lymphatic capillaries play a critical role in particle clearance, and the accumulation of NB2, but not NS, suggests possible impaired lymphatic clearance by the high aspect ratio particles. In summary, our data indicate that TiO2 NP shape alters pulmonary responses, with severity of responses being ranked as NS < NB1 < NB2. PMID:22956629

  10. A fast self-cleaning SERS-active substrate based on an inorganic-organic hybrid nanobelt film.

    PubMed

    Hao, Rui; Lin, Jie; Wang, Hua; Li, Bo; Li, Fengshi; Guo, Lin

    2015-08-28

    Surface-enhanced Raman scattering (SERS) spectroscopy, as a robust and attractive spectroscopic technique, has been widely used for the unequivocal identification of analytes, and an ideal SERS substrate that is highly sensitive and reproducible. Currently, existing substrates usually exhibit substantial sensitivity, however, achieve recyclable utilization through multi-step and complex procedures with the prerequisite of external facilities. Herein, an inorganic-organic hybrid nanobelt film assembled by novel Ag@Ag(DMSO)xCl nanobelts was proposed as an active SERS substrate. This unique substrate exhibits highly sensitive SERS detection properties, and realizes ultrafast self-cleaning by in situ photocatalytic degradation of targeted molecules adsorbed onto the film during the detection process, showing the potential for real-time online monitoring. Our study demonstrates a new concept for preparing an in situ self-cleaning substrate by the rational design and assembly of special nanomaterials.

  11. 7 CFR 1206.21 - Suspend.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE MANGO PROMOTION, RESEARCH, AND INFORMATION Mango Promotion, Research, and Information Order Definitions § 1206.21 Suspend. Suspend means...

  12. 7 CFR 1206.21 - Suspend.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE MANGO PROMOTION, RESEARCH, AND INFORMATION Mango Promotion, Research, and Information Order Definitions § 1206.21 Suspend. Suspend means...

  13. 7 CFR 1206.21 - Suspend.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE MANGO PROMOTION, RESEARCH, AND INFORMATION Mango Promotion, Research, and Information Order Definitions § 1206.21 Suspend. Suspend means...

  14. 7 CFR 1206.21 - Suspend.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE MANGO PROMOTION, RESEARCH, AND INFORMATION Mango Promotion, Research, and Information Order Definitions § 1206.21 Suspend. Suspend means...

  15. 7 CFR 1206.21 - Suspend.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE MANGO PROMOTION, RESEARCH, AND INFORMATION Mango Promotion, Research, and Information Order Definitions § 1206.21 Suspend. Suspend means...

  16. Vanadium nanobelts coated nickel foam 3D bifunctional electrode with excellent catalytic activity and stability for water electrolysis

    NASA Astrophysics Data System (ADS)

    Yu, Yu; Li, Pei; Wang, Xiaofang; Gao, Wenyu; Shen, Zongxu; Zhu, Yanan; Yang, Shuliang; Song, Weiguo; Ding, Kejian

    2016-05-01

    Pursuit of highly active, stable and low-cost electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is the key point for large-scale water splitting. A vanadium nanobelts coating on a nickel foam (V/NF) is proposed as an excellent 3D bifunctional electrode for water electrolysis here, which exhibits high activities with overpotentials of 292 and 176 mV at 10 mA cm-2 for OER and HER, respectively. When employed as a bifunctional electrocatalyst in an alkaline water electrolyzer, a cell voltage of 1.80 V was required to achieve 20 mA cm-2 with a slight increase during a 24 h durability test. The existence of the appropriate amount of nitrogen and oxygen elements in the surface region of vanadium nanobelts is regarded to be responsible for the electrocatalytic activity.Pursuit of highly active, stable and low-cost electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is the key point for large-scale water splitting. A vanadium nanobelts coating on a nickel foam (V/NF) is proposed as an excellent 3D bifunctional electrode for water electrolysis here, which exhibits high activities with overpotentials of 292 and 176 mV at 10 mA cm-2 for OER and HER, respectively. When employed as a bifunctional electrocatalyst in an alkaline water electrolyzer, a cell voltage of 1.80 V was required to achieve 20 mA cm-2 with a slight increase during a 24 h durability test. The existence of the appropriate amount of nitrogen and oxygen elements in the surface region of vanadium nanobelts is regarded to be responsible for the electrocatalytic activity. Electronic supplementary information (ESI) available: More SEM, TEM images, XRD patterns, LSV curves, XPS spectra. See DOI: 10.1039/c6nr02395a

  17. Polarization-Induced Charge Distribution at Homogeneous Zincblende/Wurtzite Heterostructural Junctions in ZnSe Nanobelts

    SciTech Connect

    Li, L.; Jin, L.; Wang, J.; Smith, D. J.; Yin, W. J.; Yan, Y.; Sang, H.; Choy, W. C. H.; McCartney, M. R.

    2012-03-08

    Homogeneous heterostructural wurtzite (WZ)/zincblende (ZB) junctions are successfully fabricated in ZnSe nanobelts. Polarity continuity across the ZB/WZ interface is demonstrated. The saw-tooth-like potential profile induced by spontaneous polarization across the WZ/ZB/WZ interfaces is identified directly at the nanoscale. The polarization-induced charge distribution across the homogeneous heterostructural interfaces is proposed as a viable alternative approach towards charge tailoring in semiconductor nanostructures.

  18. Hydrothermal synthesis of NiS nanobelts and NiS{sub 2} microspheres constructed of cuboids architectures

    SciTech Connect

    Wang Lili; Zhu Yongchun; Li Haibo; Li Qianwen; Qian Yitai

    2010-01-15

    NiS nanobelts of hexagonal phase have been hydrothermally synthesized starting from Ni(CH{sub 3}COO){sub 2}.4H{sub 2}O and Na{sub 2}S{sub 2}O{sub 3}.5H{sub 2}O at 200 deg. C for 12 h. The as-prepared nanobelts were 50 nm thick, 70-200 nm wide and more than 10 {mu}m long. As ethylenediaminetetraacetic acid (EDTA) added, in similar condition, 2 {mu}m NiS{sub 2} microspheres of cubic phase were prepared. However, as Ni{sup 2+}/S{sub 2}O{sub 3}{sup 2-} ratio was 1:1 and the temperature was decreased to 160 deg. C, 5 {mu}m NiS{sub 2} microspheres constructed of cuboids were formed. - Graphical abstract: Hexagonal NiS nanobelts and cubic NiS{sub 2} microspheres were hydrothermally synthesized in the reaction of Ni(CH{sub 3}COO){sub 2}.4H{sub 2}O and Na{sub 2}S{sub 2}O{sub 3}.5H{sub 2}O.

  19. Functionalized SnO₂ nanobelt field-effect transistor sensors for label-free detection of cardiac troponin.

    PubMed

    Cheng, Yi; Chen, Kan-Sheng; Meyer, Nancy L; Yuan, Jing; Hirst, Linda S; Chase, P Bryant; Xiong, Peng

    2011-07-15

    Real-time label-free electrical detection of proteins, including cardiac troponin (cTn), is demonstrated using functionalized SnO₂ nanobelt field-effect transistors (FETs) with integrated microfluidics. Selective biomolecular functionalization of the active SnO₂ nanobelt channel and effective passivation of the substrate surface were realized and verified through fluorescence microscopy. The validation/verification of the sensing scheme was initially demonstrated via detection of biotin-streptavidin binding: devices with single biotinylated SnO₂ nanobelts showed pronounced conductance changes in response to streptavidin binding. Importantly, the pH-dependence of the conductance changes was fully consistent with the charged states of streptavidin at different pH. Moreover, the specificity of the sensors' electrical responses was confirmed by co-labeling with quantum dots. Finally, the sensing platform was successfully applied for detection of the cardiac troponin I (cTnI) subunit within cTn, a clinically important protein marker for myocardial infarction. PMID:21652197

  20. A Single Eu-Doped In2O3 Nanobelt Device for Selective H2S Detection

    PubMed Central

    Chen, Weiwu; Liu, Yingkai; Qin, Zhaojun; Wu, Yuemei; Li, Shuanghui; Ai, Peng

    2015-01-01

    Eu-doped In2O3 nanobelts (Eu-In2O3 NBs) and pure In2O3 nanobelts (In2O3 NBs) are synthesized by the carbon thermal reduction method. Single nanobelt sensors are fabricated via an ion beam deposition system with a mesh-grid mask. The gas-sensing response properties of the Eu-In2O3 NB device and its undoped counterpart are investigated with several kinds of gases (including H2S, CO, NO2, HCHO, and C2H5OH) at different concentrations and different temperatures. It is found that the response of the Eu-In2O3 NB device to 100 ppm of H2S is the best among these gases and the sensitivity reaches 5.74, which is five times that of pure In2O3 NB at 260 °C. We also found that the former has an excellent sensitive response and great selectivity to H2S compared to the latter. Besides, there is a linear relationship between the response and H2S concentration when its concentration changes from 5 to 100 ppm and from 100 to 1000 ppm. The response/recovery time is quite short and remains stable with an increase of H2S concentration. These results mean that the doping of Eu can improve the gas-sensing performance of In2O3 NB effectually. PMID:26633404

  1. Effect of front and back gates on β-Ga2O3 nano-belt field-effect transistors

    NASA Astrophysics Data System (ADS)

    Ahn, Shihyun; Ren, Fan; Kim, Janghyuk; Oh, Sooyeoun; Kim, Jihyun; Mastro, Michael A.; Pearton, S. J.

    2016-08-01

    Field effect transistors (FETs) using SiO2 and Al2O3 as the gate oxides for the back and front sides, respectively, were fabricated on exfoliated two-dimensional (2D) β-Ga2O3 nano-belts transferred to a SiO2/Si substrate. The mechanical exfoliation and transfer process produced nano-belts with smooth surface morphologies and a uniform low defect density interface with the SiO2/Si substrate. The depletion mode nanobelt transistors exhibited better channel modulation with both front and back gates operational compared to either front or back-gating alone. The maximum transconductance was ˜4.4 mS mm-1 with front and back-gating and ˜3.7 mS mm-1 with front-gating only and a maximum drain source current density of 60 mA mm-1 was achieved at a drain-source voltage of 10 V. The FETs had on/off ratios of ˜105 at 25 °C with gate-source current densities of ˜2 × 10-3 mA mm-1 at a gate voltage of -30 V. The device characteristics were stable over more than a month for storage in air ambient and the results show the potential of 2D β-Ga2O3 for power nanoelectronics.

  2. V2O5-C-SnO2 Hybrid Nanobelts as High Performance Anodes for Lithium-ion Batteries

    PubMed Central

    Zhang, Linfei; Yang, Mingyang; Zhang, Shengliang; Wu, Zefei; Amini, Abbas; Zhang, Yi; Wang, Dongyong; Bao, Shuhan; Lu, Zhouguang; Wang, Ning; Cheng, Chun

    2016-01-01

    The superior performance of metal oxide nanocomposites has introduced them as excellent candidates for emerging energy sources, and attracted significant attention in recent years. The drawback of these materials is their inherent structural pulverization which adversely impacts their performance and makes the rational design of stable nanocomposites a great challenge. In this work, functional V2O5-C-SnO2 hybrid nanobelts (VCSNs) with a stable structure are introduced where the ultradispersed SnO2 nanocrystals are tightly linked with glucose on the V2O5 surface. The nanostructured V2O5 acts as a supporting matrix as well as an active electrode component. Compared with existing carbon-V2O5 hybrid nanobelts, these hybrid nanobelts exhibit a much higher reversible capacity and architectural stability when used as anode materials for lithium-ion batteries. The superior cyclic performance of VCSNs can be attributed to the synergistic effects of SnO2 and V2O5. However, limited data are available for V2O5-based anodes in lithium-ion battery design. PMID:27677326

  3. A Finite Element Model Of Self-Resonating Bimorph Microcantilever For Fast Temperature Cycling In A Pyroelectric Energy Harvester

    SciTech Connect

    Mostafa, Salwa; Lavrik, Nickolay V; Bannuru, Thirumalesh; Rajic, Slobodan; Islam, Syed K; Datskos, Panos G; Hunter, Scott Robert

    2011-01-01

    A self resonating bimorph cantilever structure for fast temperature cycling in a pyroelectric energy harvester has been modeled using a finite element method. The effect of constituting material properties and system parameters on the frequency and magnitude of temperature cycling and the efficiency of energy recycling using the proposed structure has been investigated. Results show that thermal contact conductance and heat source temperature play a key role in dominating the cycling frequency and efficiency of energy recycling. An optimal solution for the most efficient energy scavenging process has been sought by studying the performance trend with different variable parameters such as thermal contact conductance, heat source temperature, device aspect ratio and constituent materials of varying thermal conductivity and expansion coefficients.

  4. Piezoelectric bimorph-based shear force microscopy for the construction of noble metal plasmonic structures in air

    NASA Astrophysics Data System (ADS)

    Cai, Wei; Yang, Mu; Wang, Yingjie; Shang, Guangyi

    2015-07-01

    In this article, we present an alternative method to directly manipulate the noble metal structures in air. The method is carried out based on a home-made shear force microscope, which mainly consists of a fiber probe-bimorph beam shear force sensor, a scanning probe microscope controller, and a nano-positioning stage. The magnitude of the probe-sample interaction forces as a function of the set-point ratio is estimated, which shows that the magnitude of the forces is inversely proportional to the set-point ratio. The microscopic imaging and manipulation can be realized at the higher and lower set-point values, respectively. Typical results of imaging at the set-point ratio of larger than 90% and manipulation at that of lower than 60% are demonstrated. The results suggest that this method would provide a promising way to study the relation between plasmonic structures and optical properties on the micro/nano scale.

  5. Influence of piezoceramic to fused silica plate thickness on the radii of curvature of piezoelectric bimorph mirror

    SciTech Connect

    Libu, M.; Susanth, S.; Vasanthakumari, K. G.; Dileep Kumar, C. J.; Raghu, N.

    2012-01-15

    Piezoelectric based bimorph mirrors (PBM) find extensive use in focusing of x-ray beams. Many optical instruments require use of PBM whose radii of curvature can be tuned precisely. The 100 mm and 300 mm PBMs were fabricated with varying piezoelectric to fused silica plate thicknesses. The radii of curvature of free standing mirrors were measured as a function of voltage and it was found to decrease with increasing voltage. For a given piezoelectric plate thickness, as the fused silica thickness increases, the radii of curvature was found to increase owing to increase in stiffness of the mirror. On the other hand, for a given fused silica plate thickness, when the piezoelectric plate thickness is increased, the radii of curvature are decreased for a given electric field, due to increase in generated force. This study brings out the influence of piezoceramic to fused silica plate thickness on the radii of curvature of PBM.

  6. Fabrication and performance evaluation of a metal-based bimorph piezoelectric MEMS generator for vibration energy harvesting

    NASA Astrophysics Data System (ADS)

    Kuo, Chun-Liang; Lin, Shun-Chiu; Wu, Wen-Jong

    2016-10-01

    This paper presents the development of a bimorph microelectromechanical system (MEMS) generator for vibration energy harvesting. The bimorph generator is in cantilever beam structure formed by laminating two lead zirconate titanate thick-film layers on both sides of a stainless steel substrate. Aiming to scavenge vibration energy efficiently from the environment and transform into useful electrical energy, the two piezoelectric layers on the device can be poled for serial and parallel connections to enhance the output voltage or output current respectively. In addition, a tungsten proof mass is bonded at the tip of the device to adjust the resonance frequency. The experimental result shows superior performance the generator. At the 0.5 g base excitation acceleration level, the devices pooled for serial connection and the device poled for parallel connection possess an open-circuit output voltage of 11.6 VP-P and 20.1 VP-P, respectively. The device poled for parallel connection reaches a maximum power output of 423 μW and an output voltage of 15.2 VP-P at an excitation frequency of 143.4 Hz and an externally applied based excitation acceleration of 1.5 g, whereas the device poled serial connection achieves a maximum power output of 413 μW and an output voltage of 33.0 VP-P at an excitation frequency of 140.8 Hz and an externally applied base excitation acceleration of 1.5 g. To demonstrate the feasibility of the MEMS generator for real applications, we finished the demonstration of a self-powered Bluetooth low energy wireless temperature sensor sending readings to a smartphone with only the power from the MEMS generator harvesting from vibration.

  7. Substrate-free fabrication of self-supported V2O5 nanobelt arrays by a low-temperature solvothermal method with high electrochemical performance

    NASA Astrophysics Data System (ADS)

    Xu, Haitao; Zhang, Huijuan; Liu, Li; Fang, Ling; Wang, Yu

    2016-08-01

    In the designed synthesis, self-supported NH4V3O8 nanobelt arrays were prepared via a low-temperature solvothermal method. Then the NH4V3O8 nanobelt arrays were calcined in air atmosphere. Finally, a self-supported pattern of oriented V2O5 nanobelts was obtained for the first time. Further characterization methods certified that the growth direction of NH4V3O8 nanobelts was perpendicular to the orientation plane of self-formed NH4V3O8 sheet-like substrates. As a result, the nanobelts should stretch easily on the sheet-like substrate in an oriented manner. We prove that the solvent of ethanol plays a key role in the reaction and crystal growth process. It balances the two competing oxolation and olation reactions. Furthermore, the unique pattern served as high performance a lithium-ion battery and supercapacitor. Overall, the excellent electrochemical performances, for example, outstanding rate stability, remarkable cycling capacitance and ultrahigh capacity verify that the self-supported alignments have great potential applications in lithium-ion batteries and supercapacitors.

  8. Carbon-coated Magnéli-phase TinO2n-1 nanobelts as anodes for Li-ion batteries and hybrid electrochemical cells

    NASA Astrophysics Data System (ADS)

    Han, Wei-Qiang; Wang, Xiao-Liang

    2010-12-01

    We describe a method for preparing carbon-coated Ti9O17 nanowires using H2Ti3O7 nanobelts as precursors to react with ethane and hydrogen at high-temperature. The carbon-coating layers play a key role in restraining the sintering growth of the core during the phase transformation from H2Ti3O7 to Magnéli-phase TinO2n-1, and in retaining the morphology of nanobelts. We demonstrated that the initial reversible capacity of these Ti9O17 nanobelts attained 182 mA h g-1, a value even higher than the theoretical value of a-TiO2 (167 mA h g-1). Cyclic-voltammetry measurement supports the pseudocapacitive lithium-storage behavior of these Magnéli-phase Ti9O17 nanobelts. Furthermore, the nanobelts exhibit high power density along with excellent cycling stability in their application as hybrid electrochemical cells.

  9. Self-assembly of ultrathin Cu2MoS4 nanobelts for highly efficient visible light-driven degradation of methyl orange.

    PubMed

    Zhang, Ke; Chen, Wenxing; Lin, Yunxiang; Chen, Haiping; Haleem, Yasir A; Wu, Chuanqiang; Ye, Fei; Wang, Tianxing; Song, Li

    2015-11-21

    We demonstrate ultrathin self-assembled Cu2MoS4 nanobelts synthesized by using Cu2O as the starting sacrificial template via a hydrothermal method. The nanobelts exhibit strong light absorption over a broad wavelength spectrum, suggesting their potential application as photocatalysts. The photocatalytic activity of nanobelts is evaluated by the degradation of Methyl Orange (MO) dye under visible light irradiation. Notably, the nanobelts can completely degrade 100 mL of 15 mg mL(-1) MO in 20 minutes with excellent recycling and structural stability, suggesting their excellent photocatalytic performance. In comparison with a sheet-like sample, the high efficiency of the self-assembled Cu2MoS4 nanobelts is attributed to a high surface area and a unique band gap, agreeing with the nitrogen adsorption analysis and photoluminescence spectra. This study offers a self-assembled synthetic route to create new multifunctional nanoarchitectures composed of atomic layers, and thus may open a window for greatly extending potential applications in water pollution treatment, photocatalytic water-splitting, solar cells and other related fields. PMID:26371057

  10. Catalyst-free vapour-solid technique for deposition of Bi2Te3 and Bi2Se3 nanowires/nanobelts with topological insulator properties

    NASA Astrophysics Data System (ADS)

    Andzane, J.; Kunakova, G.; Charpentier, S.; Hrkac, V.; Kienle, L.; Baitimirova, M.; Bauch, T.; Lombardi, F.; Erts, D.

    2015-09-01

    We present a simple two-stage vapour-solid synthesis method for the growth of bismuth chalcogenide (Bi2Te3, Bi2Se3) topological insulator nanowires/nanobelts by using Bi2Se3 or Bi2Te3 powders as source materials. During the first stage of the synthesis process nanoplateteles, serving as ``catalysts'' for further nanowire/nanobelt growth, are formed. At a second stage of the synthesis, the introduction of a N2 flow at 35 Torr pressure in the chamber induces the formation of free standing nanowires/nanobelts. The synthesised nanostructures demonstrate a layered single-crystalline structure and Bi : Se and Bi : Te ratios 40 : 60 at% for both Bi2Se3 and Bi2Te3 nanowires/nanobelts. The presence of Shubnikov de Haas oscillations in the longitudinal magneto-resistance of the nanowires/nanobelts and their specific angular dependence confirms the existence of 2D topological surface states in the synthesised nanostructures.

  11. Catalyst-free vapour-solid technique for deposition of Bi2Te3 and Bi2Se3 nanowires/nanobelts with topological insulator properties.

    PubMed

    Andzane, J; Kunakova, G; Charpentier, S; Hrkac, V; Kienle, L; Baitimirova, M; Bauch, T; Lombardi, F; Erts, D

    2015-10-14

    We present a simple two-stage vapour-solid synthesis method for the growth of bismuth chalcogenide (Bi2Te3, Bi2Se3) topological insulator nanowires/nanobelts by using Bi2Se3 or Bi2Te3 powders as source materials. During the first stage of the synthesis process nanoplateteles, serving as "catalysts" for further nanowire/nanobelt growth, are formed. At a second stage of the synthesis, the introduction of a N2 flow at 35 Torr pressure in the chamber induces the formation of free standing nanowires/nanobelts. The synthesised nanostructures demonstrate a layered single-crystalline structure and Bi : Se and Bi : Te ratios 40 : 60 at% for both Bi2Se3 and Bi2Te3 nanowires/nanobelts. The presence of Shubnikov de Haas oscillations in the longitudinal magneto-resistance of the nanowires/nanobelts and their specific angular dependence confirms the existence of 2D topological surface states in the synthesised nanostructures. PMID:26365282

  12. Substrate-free fabrication of self-supported V2O5 nanobelt arrays by a low-temperature solvothermal method with high electrochemical performance.

    PubMed

    Xu, Haitao; Zhang, Huijuan; Liu, Li; Fang, Ling; Wang, Yu

    2016-08-01

    In the designed synthesis, self-supported NH4V3O8 nanobelt arrays were prepared via a low-temperature solvothermal method. Then the NH4V3O8 nanobelt arrays were calcined in air atmosphere. Finally, a self-supported pattern of oriented V2O5 nanobelts was obtained for the first time. Further characterization methods certified that the growth direction of NH4V3O8 nanobelts was perpendicular to the orientation plane of self-formed NH4V3O8 sheet-like substrates. As a result, the nanobelts should stretch easily on the sheet-like substrate in an oriented manner. We prove that the solvent of ethanol plays a key role in the reaction and crystal growth process. It balances the two competing oxolation and olation reactions. Furthermore, the unique pattern served as high performance a lithium-ion battery and supercapacitor. Overall, the excellent electrochemical performances, for example, outstanding rate stability, remarkable cycling capacitance and ultrahigh capacity verify that the self-supported alignments have great potential applications in lithium-ion batteries and supercapacitors. PMID:27335084

  13. Synthesis, characterizations, and field emission studies of crystalline Na{sub 2}V{sub 6}O{sub 16} nanobelt paper

    SciTech Connect

    Lim, S. H.; Lin, J. Y.; Zhu, Y. W.; Sow, C. H.; Ji, W.

    2006-07-01

    Crystalline Na{sub 2}V{sub 6}O{sub 16}{center_dot}3H{sub 2}O nanobelts have been synthesized by refluxing V{sub 2}O{sub 5} and NaF and self-weaved into a sheet of paper via a vacuum filtration process. Scanning electron microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy were used to characterize the morphology, structure, and chemical composition of the nanobelt papers. The dehydrated Na{sub 2}V{sub 6}O{sub 16} nanobelts are excellent field emission candidates, with a low turn-on field of 6.8 V/{mu}m, a large current density up to 2.5 mA/cm{sup 2} at an electric field of 10 V/{mu}m, and a very uniform distribution of emission sites.

  14. Wettability of partially suspended graphene

    PubMed Central

    Ondarçuhu, Thierry; Thomas, Vincent; Nuñez, Marc; Dujardin, Erik; Rahman, Atikur; Black, Charles T.; Checco, Antonio

    2016-01-01

    The dependence of the wettability of graphene on the nature of the underlying substrate remains only partially understood. Here, we systematically investigate the role of liquid-substrate interactions on the wettability of graphene by varying the area fraction of suspended graphene from 0 to 95% by means of nanotextured substrates. We find that completely suspended graphene exhibits the highest water contact angle (85° ± 5°) compared to partially suspended or supported graphene, regardless of the hydrophobicity (hydrophilicity) of the substrate. Further, 80% of the long-range water-substrate interactions are screened by the graphene monolayer, the wettability of which is primarily determined by short-range graphene-liquid interactions. By its well-defined chemical and geometrical properties, supported graphene therefore provides a model system to elucidate the relative contribution of short and long range interactions to the macroscopic contact angle. PMID:27072195

  15. Wettability of partially suspended graphene

    DOE PAGES

    Ondarçuhu, Thierry; Thomas, Vincent; Nuñez, Marc; Dujardin, Erik; Rahman, Atikur; Black, Charles T.; Checco, Antonio

    2016-04-13

    Dependence on the wettability of graphene on the nature of the underlying substrate remains only partially understood. We systematically investigate the role of liquid-substrate interactions on the wettability of graphene by varying the area fraction of suspended graphene from 0 to 95% by means of nanotextured substrates. We find that completely suspended graphene exhibits the highest water contact angle (85° ± 5°) compared to partially suspended or supported graphene, regardless of the hydrophobicity (hydrophilicity) of the substrate. Moreover, 80% of the long-range water-substrate interactions are screened by the graphene monolayer, the wettability of which is primarily determined by short-range graphene-liquidmore » interactions. By its well-defined chemical and geometrical properties, supported graphene therefore provides a model system to elucidate the relative contribution of short and long range interactions to the macroscopic contact angle.« less

  16. Synthesis of one-dimensional porous Co{sub 3}O{sub 4} nanobelts and their ethanol gas sensing properties

    SciTech Connect

    Che, Hongwei; Liu, Aifeng; Hou, Junxian; Zhang, Xiaoliang; Bai, Yongmei; Mu, Jingbo; Wang, Renliang

    2014-11-15

    Graphical abstract: 1D porous porous Co{sub 3}O{sub 4} nanobelts were synthesized via a facile route without use of any surfactants or organic solvent, exhibiting ethanol gas sensing properties superior to the commercial Co{sub 3}O{sub 4} powders. - Highlights: • One-dimensional porous Co{sub 3}O{sub 4} nanobelts were synthesized. • The belt-like morphology can be finely controlled via adjusting the reaction parameters. • The evolution process of porous Co{sub 3}O{sub 4} nanobelts was investigated. • Porous Co{sub 3}O{sub 4} nanobelts exhibit superior ethanol gas sensing properties. - Abstract: In this paper, one-dimensional porous Co{sub 3}O{sub 4} nanobelts were synthesized via a facile template-free hydrothermal method and subsequent the thermal decomposition. Their microstructures and morphologies were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and N{sub 2} adsorption–desorption techniques. The results indicate that the reaction parameters such as the molar ratio of Co(NO{sub 3}){sub 2}·6H{sub 2}O to C{sub 2}H{sub 4}N{sub 4}, the amount of Co(NO{sub 3}){sub 2}·6H{sub 2}O, the hydrothermal temperature and time play crucial rules in controlling the microstructures and morphologies of the as-prepared cobalt precursors. A possible formation mechanism was proposed. Moreover, the obtained porous Co{sub 3}O{sub 4} nanobelts exhibit ethanol gas sensing properties superior to the commercial Co{sub 3}O{sub 4} powders at a working temperature of 200 °C, suggesting their potential applications as nanosensors.

  17. Magnetically suspended reaction wheel assembly

    NASA Technical Reports Server (NTRS)

    Stocking, G.

    1984-01-01

    The magnetically suspended reaction wheel assembly (MSRWA) is the product of a development effort funded by the Air Force Materials Laboratory (AFML) at Wright Patterson AFB. The specific objective of the project was to establish the manufacturing processes for samarium cobalt magnets and demonstrate their use in a space application. The development was successful on both counts. The application portion of the program, which involves the magnetically suspended reaction wheel assembly, is emphasized. The requirements for the reaction wheel were based on the bias wheel requirements of the DSP satellite. The tasks included the design, fabrication, and test of the unit to the DSP program qualification requirements.

  18. Vaporization-condensation-recrystallization process-mediated synthesis of helical m-aminobenzoic acid nanobelts.

    PubMed

    Yoon, Seok Min; Hwang, In-Chul; Shin, Namsoo; Ahn, Docheon; Lee, Sang Joo; Lee, Jin Yong; Choi, Hee Cheul

    2007-11-01

    One-dimensional (1D) helical organic nanostructures were synthesized by a modified vapor-solid (VS) process, called the vaporization-condensation-recrystallization (VCR) process. The conventional solution-phase synthetic methods generally mediate self-assemblies of repeating unit molecules. To provide enough intermolecular interaction forces among the unit molecules, such strategy requires specific designs and syntheses of complex unit molecules as they possess numerous functional groups including phenyl rings, hydroxyl groups, long aliphatic chains, etc. On the contrary, we found that small and simple organic molecules, for example, m-ABA, could be self-assembled by the VCR process, resulting in 1D helical organic nanostructures. When m-aminobenzoic acid (m-ABA) powders were vaporized and transported to be condensed on a cooler region, the condensates were recrystallized into 1D helical nanobelts. Each step of the VCR process was confirmed from control experiments performed by varying reaction times, substrate types, and reaction temperatures. Powder XRD data, SAED analysis, and theoretical calculations revealed that dimers of m-ABA molecules have repeating units, and the growth axis of m-ABA nanohelices is [100].

  19. Piezotronic Effect in Strain-Gated Transistor of a-Axis GaN Nanobelt.

    PubMed

    Yu, Ruomeng; Wang, Xingfu; Peng, Wenbo; Wu, Wenzhuo; Ding, Yong; Li, Shuti; Wang, Zhong Lin

    2015-10-27

    Due to the non-centrosymmetric crystal structures, wurtzite family semiconducting materials possess piezoelectric properties and exhibit polarizations along certain directions upon straining. Utilizing strain-induced piezoelectric polarization charges to modulate the energy band structures and thus to tune/control the transport processes of charge carriers is referred to as the piezotronic effect. Distinct from the previous studies of c-axis GaN nanowires, here we systematically study the piezotronic-effect-induced modifications of energy band structures and the corresponding influence on electronic transport properties of a-axis GaN nanobelts. The physical mechanism is carefully illustrated and further confirmed by theoretical simulations via finite element analysis. The spatial distributions of local carrier concentration and the energy band diagrams of a-axis GaN under various straining conditions are calculated. This work provides a thorough understanding of strain-gated transport properties of a-axis GaN piezotronic transistors and its future applications in semiconductor devices.

  20. Synthesis and Photoluminescence of Single-Crystalline Fe(III)-Doped CdS Nanobelts.

    PubMed

    Kamran, Muhammad Arshad; Zou, Bingsuo; Majid, A; Alharbil, Thamer; Saeed, M A; Abdullah, Ali; Javed, Qurat-ul-ain

    2016-04-01

    In this paper, we report the synthesis and optical properties of Fe(III) doped CdS nanobelts (NBs) via simple Chemical Vapor Deposition (CVD) technique to explore their potential in nano-optics. The energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) analysis manifested the presence of Fe(III) ions in the NBs subsequently confirmed by the peak shifting to lower phonon energies as recorded by Raman spectra and shorter lifetime in ns. Photoluminescence (PL) spectrum investigations of the single Fe(III)-doped CdS NBs depicted an additional PL peak centered at 573 nm (orange emission) in addition to the bandedge(BE) emission. The redshift and decrease in the BE intensity of the PL peaks, as compared to the bulk CdS, confirmed the quenching of spectra upon Fe doping. The synthesis and orange emission for Fe-doped CdS NBs have been observed for the first time and point out their potential in nanoscale devices. PMID:27451769

  1. Controllable synthesis and electrochemical hydrogen storage properties of Sb2Se3 ultralong nanobelts with urchin-like structures

    NASA Astrophysics Data System (ADS)

    Jin, Rencheng; Chen, Gang; Pei, Jian; Sun, Jingxue; Wang, Yang

    2011-09-01

    The controlled synthesis of one-dimensional and three-dimensional Sb2Se3 nanostructures has been achieved by a facile solvothermal process in the presence of citric acid. By simply controlling the concentration of citric acid, the nucleation, growth direction and exposed facet can be readily tuned, which brings the different morphologies and nanostructures to the final products. The as-prepared products have been characterized by means of X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM and selected area electron diffraction. Based on the electron microscope observations, a possible growth mechanism of Sb2Se3 with distinctive morphologies including ultralong nanobelts, hierarchical urchin-like nanostructures is proposed and discussed in detail. The electrochemical hydrogen storage measurements reveal that the morphology plays a key role on the hydrogen storage capacity of Sb2Se3 nanostructures. The Sb2Se3 ultralong nanobelts with high percentage of {-111} facets exhibit higher hydrogen storage capacity (228.5 mA h g-1) and better cycle stability at room temperature.The controlled synthesis of one-dimensional and three-dimensional Sb2Se3 nanostructures has been achieved by a facile solvothermal process in the presence of citric acid. By simply controlling the concentration of citric acid, the nucleation, growth direction and exposed facet can be readily tuned, which brings the different morphologies and nanostructures to the final products. The as-prepared products have been characterized by means of X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM and selected area electron diffraction. Based on the electron microscope observations, a possible growth mechanism of Sb2Se3 with distinctive morphologies including ultralong nanobelts, hierarchical urchin-like nanostructures is proposed and discussed in detail. The

  2. Synthesis of {100} facet dominant anatase TiO2 nanobelts and the origin of facet-dependent photoreactivity.

    PubMed

    Pan, Feng; Wu, Kai; Li, Hexing; Xu, Guoqin; Chen, Wei

    2014-11-10

    Sword-like anatase TiO2 nanobelts exposed with 78% clean {100} facets were synthesized and the facet-dependent photoreactivity of anatase TiO2 was investigated. By quantitative comparison with the reference {001} facets, the {100} facets possessed about ten-times higher active sites density than that on {001} facets, resulting in higher photoreaction efficiency. After the active sites density normalization, the {100} and {001} facets exhibited distinct wavelength-dependent photocatalytic performance, attributed to the anisotropic electronic structures in TiO2 crystals. PMID:25255881

  3. 29 CFR 98.1010 - Suspending official.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Suspending official. 98.1010 Section 98.1010 Labor Office of the Secretary of Labor GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) Definitions § 98.1010 Suspending official. (a) Suspending official means an agency official who is authorized to impose...

  4. 34 CFR 85.1010 - Suspending official.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... designated by the agency head. (b) Authority: E.O. 12549 (3 CFR, 1986 Comp., p. 189); E.O 12689 (3 CFR, 1989... 34 Education 1 2010-07-01 2010-07-01 false Suspending official. 85.1010 Section 85.1010 Education...) Definitions § 85.1010 Suspending official. (a) Suspending official means an agency official who is...

  5. 31 CFR 19.1010 - Suspending official.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Suspending official. 19.1010 Section 19.1010 Money and Finance: Treasury Office of the Secretary of the Treasury GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) Definitions § 19.1010 Suspending official. (a) Suspending...

  6. 22 CFR 208.1010 - Suspending official.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Suspending official. 208.1010 Section 208.1010 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) Definitions § 208.1010 Suspending official. (a) Suspending official means an agency official...

  7. 21 CFR 1404.1010 - Suspending official.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Suspending official. 1404.1010 Section 1404.1010 Food and Drugs OFFICE OF NATIONAL DRUG CONTROL POLICY GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) Definitions § 1404.1010 Suspending official. (a) Suspending official means an agency official...

  8. 2 CFR 180.1010 - Suspending official.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 2 Grants and Agreements 1 2010-01-01 2010-01-01 false Suspending official. 180.1010 Section 180.1010 Grants and Agreements OFFICE OF MANAGEMENT AND BUDGET GOVERNMENTWIDE GUIDANCE FOR GRANTS AND...) Definitions § 180.1010 Suspending official. (a) Suspending official means an agency official who is...

  9. 29 CFR 1471.1010 - Suspending official.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 4 2010-07-01 2010-07-01 false Suspending official. 1471.1010 Section 1471.1010 Labor Regulations Relating to Labor (Continued) FEDERAL MEDIATION AND CONCILIATION SERVICE GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) Definitions § 1471.1010 Suspending official. (a) Suspending...

  10. Suspended Solids Profiler Shop Test Report

    SciTech Connect

    STAEHR, T.W.

    2000-01-19

    The Suspended Solids Profiler (SSP) Instrument is planned to be installed in the AZ-101 tank to measure suspended solids concentrations during mixer pump testing. The SSP sensor uses a reflectance measurement principle to determine the suspended solids concentrations. The purpose of this test is to provide a documented means of verifying that the functional components of the SSP operate properly.

  11. High detectivity solar-blind high-temperature deep-ultraviolet photodetector based on multi-layered (l00) facet-oriented β-Ga₂O₃ nanobelts.

    PubMed

    Zou, Rujia; Zhang, Zhenyu; Liu, Qian; Hu, Junqing; Sang, Liwen; Liao, Meiyong; Zhang, Wenjun

    2014-05-14

    Fabrication of a high-temperature deep-ultraviolet photodetector working in the solar-blind spectrum range (190-280 nm) is a challenge due to the degradation in the dark current and photoresponse properties. Herein, β-Ga2O3 multi-layered nanobelts with (l00) facet-oriented were synthesized, and were demonstrated for the first time to possess excellent mechanical, electrical properties and stability at a high temperature inside a TEM studies. As-fabricated DUV solar-blind photodetectors using (l00) facet-oriented β-Ga2O3 multi-layered nanobelts demonstrated enhanced photodetective performances, that is, high sensitivity, high signal-to-noise ratio, high spectral selectivity, high speed, and high stability, importantly, at a temperature as high as 433 K, which are comparable to other reported semiconducting nanomaterial photodetectors. In particular, the characteristics of the photoresponsivity of the β-Ga2O3 nanobelt devices include a high photoexcited current (>21 nA), an ultralow dark current (below the detection limit of 10(-14) A), a fast time response (<0.3 s), a high R(λ) (≈851 A/W), and a high EQE (~4.2 × 10(3)). The present fabricated facet-oriented β-Ga2O3 multi-layered nanobelt based devices will find practical applications in photodetectors or optical switches for high-temperature environment. PMID:24520013

  12. Control of the threshold voltage in ZnO nanobelt field-effect transistors by using MoO x thin film

    NASA Astrophysics Data System (ADS)

    Qian, Haolei; Fang, Yanjun; Gu, Lin; Lu, Ren; Zhao, Ming; Wang, Wei; Wang, Yewu; Sha, Jian

    2016-07-01

    We report on the feasible control of the threshold voltage (V th) in ultra-thin ZnO nanobelt FETs by using substoichiometric molybdenum trioxide (MoO x , x < 3) either as a modification layer on the surface of ZnO nanobelts or as electrodes instead of the widely used Ti/Au. ZnO nanobelt FETs using Ti/Au as the electrodes usually exhibit a negative threshold voltage, indicating n-channel depletion mode behavior, whereas ZnO FETs with MoO x /Au electrodes instead of Ti/Au show a positive shift of threshold voltage, exhibiting an n-channel type enhancement mode, which can be explained by a high Schottky barrier created at the interface of MoO x and the ZnO channel. In contrast, the decoration on the surface of ZnO channel by MoO x significantly increases the zero-bias conductivity and electron carrier concentration, and then negatively shifts the threshold voltage. We propose that MoO x thin film may play a passivation effect role, much more so than the doping effect role, due to the large amount of adsorbed species on as-grown ZnO nanobelts, especially oxygen species.

  13. Exfoliated β-Ga2O3 nano-belt field-effect transistors for air-stable high power and high temperature electronics.

    PubMed

    Kim, Janghyuk; Oh, Sooyeoun; Mastro, Michael A; Kim, Jihyun

    2016-06-21

    This study demonstrated the exfoliation of a two-dimensional (2D) β-Ga2O3 nano-belt and subsequent processing into a thin film transistor structure. This mechanical exfoliation and transfer method produces β-Ga2O3 nano-belts with a pristine surface as well as a continuous defect-free interface with the SiO2/Si substrate. This β-Ga2O3 nano-belt based transistor displayed an on/off ratio that increased from approximately 10(4) to 10(7) over the operating temperature range of 20 °C to 250 °C. No electrical breakdown was observed in our measurements up to VDS = +40 V and VGS = -60 V between 25 °C and 250 °C. Additionally, the electrical characteristics were not degraded after a month-long storage in ambient air. The demonstration of high-temperature/high-voltage operation of quasi-2D β-Ga2O3 nano-belts contrasts with traditional 2D materials such as transition metal dichalcogenides that intrinsically have limited temperature and power operational envelopes owing to their narrow bandgap. This work motivates the application of 2D β-Ga2O3 to high power nano-electronic devices for harsh environments such as high temperature chemical sensors and photodetectors as well as the miniaturization of power circuits and cooling systems in nano-electronics. PMID:27230724

  14. Self-assembly of palladium nanoparticles: Synthesis of nanobelts, nanoplates and nanotrees using vitamin B1 and their application in carbon-carbon coupling reactions

    EPA Science Inventory

    An environmentally friendly one-step method to synthesize palladium (Pd) nanobelts, nanoplates and nanotrees using vitamin B1 without using any special capping agents at room temperature is described. This greener method, which uses water as benign solvent and vitamin B1 as a red...

  15. High detectivity solar-blind high-temperature deep-ultraviolet photodetector based on multi-layered (l00) facet-oriented β-Ga₂O₃ nanobelts.

    PubMed

    Zou, Rujia; Zhang, Zhenyu; Liu, Qian; Hu, Junqing; Sang, Liwen; Liao, Meiyong; Zhang, Wenjun

    2014-05-14

    Fabrication of a high-temperature deep-ultraviolet photodetector working in the solar-blind spectrum range (190-280 nm) is a challenge due to the degradation in the dark current and photoresponse properties. Herein, β-Ga2O3 multi-layered nanobelts with (l00) facet-oriented were synthesized, and were demonstrated for the first time to possess excellent mechanical, electrical properties and stability at a high temperature inside a TEM studies. As-fabricated DUV solar-blind photodetectors using (l00) facet-oriented β-Ga2O3 multi-layered nanobelts demonstrated enhanced photodetective performances, that is, high sensitivity, high signal-to-noise ratio, high spectral selectivity, high speed, and high stability, importantly, at a temperature as high as 433 K, which are comparable to other reported semiconducting nanomaterial photodetectors. In particular, the characteristics of the photoresponsivity of the β-Ga2O3 nanobelt devices include a high photoexcited current (>21 nA), an ultralow dark current (below the detection limit of 10(-14) A), a fast time response (<0.3 s), a high R(λ) (≈851 A/W), and a high EQE (~4.2 × 10(3)). The present fabricated facet-oriented β-Ga2O3 multi-layered nanobelt based devices will find practical applications in photodetectors or optical switches for high-temperature environment.

  16. Electromechanically Tunable Suspended Optical Nanoantenna.

    PubMed

    Chen, Kai; Razinskas, Gary; Feichtner, Thorsten; Grossmann, Swen; Christiansen, Silke; Hecht, Bert

    2016-04-13

    Coupling mechanical degrees of freedom with plasmonic resonances has potential applications in optomechanics, sensing, and active plasmonics. Here we demonstrate a suspended two-wire plasmonic nanoantenna acting like a nanoelectrometer. The antenna wires are supported and electrically connected via thin leads without disturbing the antenna resonance. As a voltage is applied, equal charges are induced on both antenna wires. The resulting equilibrium between the repulsive Coulomb force and the restoring elastic bending force enables us to precisely control the gap size. As a result the resonance wavelength and the field enhancement of the suspended optical nanoantenna can be reversibly tuned. Our experiments highlight the potential to realize large bandwidth optical nanoelectromechanical systems. PMID:27002492

  17. Synthesis, characterization, and bioactivity of carboxylic acid-functionalized titanium dioxide nanobelts

    PubMed Central

    2014-01-01

    Background Surface modification strategies to reduce engineered nanomaterial (ENM) bioactivity have been used successfully in carbon nanotubes. This study examined the toxicity and inflammatory potential for two surface modifications (humic acid and carboxylation) on titanium nanobelts (TNB). Methods The in vitro exposure models include C57BL/6 alveolar macrophages (AM) and transformed human THP-1 cells exposed to TNB for 24 hrs in culture. Cell death and NLRP3 inflammasome activation (IL-1β release) were monitored. Short term (4 and 24 hr) in vivo studies in C57BL/6, BALB/c and IL-1R null mice evaluated inflammation and cytokine release, and cytokine release from ex vivo cultured AM. Results Both in vitro cell models suggest that the humic acid modification does not significantly affect TNB bioactivity, while carboxylation reduced both toxicity and NLRP3 inflammasome activation. In addition, short term in vivo exposures in both C57BL/6 and IL-1R null mouse strains demonstrated decreased markers of inflammation, supporting the in vitro finding that carboxylation is effective in reducing bioactivity. TNB instillations in IL-1R null mice demonstrated the critical role of IL-1β in initiation of TNB-induced lung inflammation. Neutrophils were completely absent in the lungs of IL-1R null mice instilled with TNB for 24 hrs. However, the cytokine content of the IL-1R null mice lung lavage samples indicated that other inflammatory agents, IL-6 and TNF-α were constitutively elevated indicating a potential compensatory inflammatory mechanism in the absence of IL-1 receptors. Conclusions Taken together, the data suggests that carboxylation, but not humic acid modification of TNB reduces, but does not totally eliminate bioactivity of TNB, which is consistent with previous studies of other long aspect ratio nanomaterials such as carbon nanotubes. PMID:25179214

  18. High-performance ultraviolet photodetectors based on solution-grown ZnS nanobelts sandwiched between graphene layers

    PubMed Central

    Kim, Yeonho; Kim, Sang Jin; Cho, Sung-Pyo; Hong, Byung Hee; Jang, Du-Jeon

    2015-01-01

    Ultraviolet (UV) light photodetectors constructed from solely inorganic semiconductors still remain unsatisfactory because of their low electrical performances. To overcome this limitation, the hybridization is one of the key approaches that have been recently adopted to enhance the photocurrent. High-performance UV photodetectors showing stable on-off switching and excellent spectral selectivity have been fabricated based on the hybrid structure of solution-grown ZnS nanobelts and CVD-grown graphene. Sandwiched structures and multilayer stacking strategies have been applied to expand effective junction between graphene and photoactive ZnS nanobelts. A multiply sandwich-structured photodetector of graphene/ZnS has shown a photocurrent of 0.115 mA under illumination of 1.2 mWcm−2 in air at a bias of 1.0 V, which is higher 107 times than literature values. The multiple-sandwich structure of UV-light sensors with graphene having high conductivity, flexibility, and impermeability is suggested to be beneficial for the facile fabrication of UV photodetectors with extremely efficient performances. PMID:26197784

  19. TiO{sub 2} nanobelts photocatalysts decorated with Bi{sub 2}WO{sub 6} nanocrystals: Preparation and enhanced photocatalytic activity

    SciTech Connect

    Li, Yang; Wu, Wenjian; Wu, Mingzai; Dai, Peng; Zhang, Lili; Sun, Zhaoqi; Li, Guang; Liu, Xiansong; Chen, Xiaoshuang; Zheng, Xiuwen

    2014-07-01

    Highlights: • TiO{sub 2} nanobelts decorated with Bi{sub 2}WO{sub 6} nanocrystals have been prepared. • The introduction of Bi{sub 2}WO{sub 6} nanocrystals can induce red-shift of absorption edge. • The Bi{sub 2}WO{sub 6}/TiO{sub 2} composites show higher photocatalytic activity than TiO{sub 2} nanobelts. • The Bi{sub 2}WO{sub 6}/TiO{sub 2} composites have long-time recyclable ability of photodegradation. - Abstract: In this paper, the controllable preparation of one-dimensional TiO{sub 2} nanobelts decorated with Bi{sub 2}WO{sub 6} nanocrystals based on Ti foils was reported using two-step hydrothermal treatment method. X-ray photoelectron spectroscopy measurement results exhibited the binding energy changes of Ti and O elements, implying the strong adhesion of Bi{sub 2}WO{sub 6} nanocrystals onto the surface of TiO{sub 2} nanobelts. The ultraviolet–visible (UV–vis) absorption spectra showed that the introduction of Bi{sub 2}WO{sub 6} nanocrystals could induce the red-shift of absorption edge and exhibited a broad absorption band in the visible region, which extended the scope of absorption spectrum and help to improve the photocatalytic degradation efficiency. The photocatalytic experiment results revealed that Bi{sub 2}WO{sub 6}/TiO{sub 2} composites possess higher photocatalytic activities toward methyl orange than pure TiO{sub 2} nanobelts. The degradation efficiency of 90% after 5 cycles indicated that the as-prepared composite photocatalysts exhibited excellent long-time recyclable ability for the degradation of contaminants.

  20. Fe(NO3)3-assisted large-scale synthesis of Si3N4 nanobelts from quartz and graphite by carbothermal reduction–nitridation and their photoluminescence properties

    PubMed Central

    Liu, Shuyue; Fang, Minghao; Huang, Zhaohui; Huang, Juntong; Ji, Haipeng; Liu, Haitao; Liu, Yan-gai; Wu, Xiaowen

    2015-01-01

    The large-scale synthesis of Si3N4 nanobelts from quartz and graphite on a graphite-felt substrate was successfully achieved by catalyst-assisted carbothermal reduction–nitridation. The phase composition, morphology, and microstructure of Si3N4 nanobelts were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, and high-resolution transmission electron microscopy. The Si3N4 nanobelts were ~4–5 mm long and ~60 nm thick and exhibited smooth surfaces and flexible shapes. The Si3N4 nanobelts were well crystallized and grow along the [101] direction. The growth is dominated by the combined mechanisms of vapor–liquid–solid base growth and vapor–solid tip growth. The Fe(NO3)3 played a crucial role in promoting the nanobelt formation in the initial stage. The room-temperature photoluminescence spectrum of Si3N4 nanobelts consists of three emission peaks centered at 413, 437, and 462 nm, indicating potential applications in optoelectronic nanodevices. PMID:25757903

  1. Fe(NO3)3-assisted large-scale synthesis of Si₃N₄ nanobelts from quartz and graphite by carbothermal reduction-nitridation and their photoluminescence properties.

    PubMed

    Liu, Shuyue; Fang, Minghao; Huang, Zhaohui; Huang, Juntong; Ji, Haipeng; Liu, Haitao; Liu, Yan-gai; Wu, Xiaowen

    2015-01-01

    The large-scale synthesis of Si3N4 nanobelts from quartz and graphite on a graphite-felt substrate was successfully achieved by catalyst-assisted carbothermal reduction-nitridation. The phase composition, morphology, and microstructure of Si3N4 nanobelts were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, and high-resolution transmission electron microscopy. The Si3N4 nanobelts were ~4-5 mm long and ~60 nm thick and exhibited smooth surfaces and flexible shapes. The Si3N4 nanobelts were well crystallized and grow along the [101] direction. The growth is dominated by the combined mechanisms of vapor-liquid-solid base growth and vapor-solid tip growth. The Fe(NO3)3 played a crucial role in promoting the nanobelt formation in the initial stage. The room-temperature photoluminescence spectrum of Si3N4 nanobelts consists of three emission peaks centered at 413, 437, and 462 nm, indicating potential applications in optoelectronic nanodevices. PMID:25757903

  2. Modeling and identification of nonlinear electroelastic and dissipative parameters for PZT-5A and PZT-5H bimorphs: a dynamical systems approach

    NASA Astrophysics Data System (ADS)

    Leadenham, Stephen; Ferri, Brian; Erturk, Alper

    2015-04-01

    Electroelastic and dissipative nonlinearities of commonly used soft piezoelectrics (PZT-5A and PZT-5H) are pronounced in various engineering applications such as actuation, sensing, vibration control, and most recently, in energy harvesting from dynamical systems. The present work investigates the nonlinear nonconservative dynamic behavior of bimorph piezoelectric cantilevers under low-to-high excitation levels with a focus on most popular soft piezoceramics: PZT-5A and PZT-5H. A unified mathematical framework we recently developed is analyzed by using the method of harmonic balance to identify and validate nonlinear system parameters based on a set of rigorous experiments for different samples.

  3. Measuring suspended sediment: Chapter 10

    USGS Publications Warehouse

    Gray, J.R.; Landers, M.N.

    2013-01-01

    Suspended sediment in streams and rivers can be measured using traditional instruments and techniques and (or) surrogate technologies. The former, as described herein, consists primarily of both manually deployed isokinetic samplers and their deployment protocols developed by the Federal Interagency Sedimentation Project. They are used on all continents other than Antarctica. The reliability of the typically spatially rich but temporally sparse data produced by traditional means is supported by a broad base of scientific literature since 1940. However, the suspended sediment surrogate technologies described herein – based on hydroacoustic, nephelometric, laser, and pressure difference principles – tend to produce temporally rich but in some cases spatially sparse datasets. The value of temporally rich data in the accuracy of continuous sediment-discharge records is hard to overstate, in part because such data can often overcome the shortcomings of poor spatial coverage. Coupled with calibration data produced by traditional means, surrogate technologies show considerable promise toward providing the fluvial sediment data needed to increase and bring more consistency to sediment-discharge measurements worldwide.

  4. New Effects of Aging and Lattice Intercalation on Surface Properties of Titanate Nanobelts

    NASA Astrophysics Data System (ADS)

    Williams, Roger

    Titanate nanobelts (NBs) have structural characteristics beyond that of clays. Due to a negatively charged lattice matrix of edge-shared TiO 6-octahedra, the location of intercalated cations within the interlayer space may dictate the charge-conductions. This environment may in turn govern the lattice-framework's stability and surface properties, based upon our preliminary data. On that basis, these nanomaterials have been found in our lab to possess superb biological compatibility that is closely related to the types of the intercalated cations. In addition, a prolonged agitation was proven to enable us to manipulate the titanate NBs' length. In a parallel study, a ripening was observed in the post-synthesis aging process at room temperature (RT). This process implied, for the first time, a new way of changing the NBs' aspect ratio in nanosynthesis. This novel post-synthesis manipulation of aspect ratio has enabled us to successfully improve our yield of the NB-membrane by four folds, which is significant in scale-up fabrication of the NB-entangled membranes, which have shown interest as a proton exchange membrane (PEM) in fuel cells (PEMFC) and gas sensing capabilities. PEMFCs provide the highest power density in comparison with all other fuel cell types currently available. In order to improve the fuel cells efficiency, further advancements into enhancing the thermal stability while maintaining adequate hydration levels of the PEM membrane is continually sought after. Unfortunately, the polymer structure of Nafion(c) membranes structural stability and water retention falls short at elevated temperatures. However, based on our preliminary data, intercalated titanate NBs/Nafion (c) composites may hold the key to overcoming these technological drawbacks. Lastly, aging and surface modification of titanate materials has been used to attain the high selectivity and sensitivity in electrochemical sensing when applied to an electrode surface. Our initial findings

  5. 7 CFR 1216.27 - Suspend.

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  18. 7 CFR 1216.27 - Suspend.

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  19. 7 CFR 1216.27 - Suspend.

    Code of Federal Regulations, 2013 CFR

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  20. Au/TiO2 nanobelt heterostructures for the detection of cancer cells and anticancer drug activity by potential sensing

    NASA Astrophysics Data System (ADS)

    Cui, Jingjie; Chen, Jing; Chen, Shaowei; Gao, Li; Xu, Ping; Li, Hong

    2016-03-01

    Cancer is a cell dysfunction disease. The detection of cancer cells is extremely important for early diagnosis and clinical treatments. At present, the pretreatment for the detection of cancer cells is costly, complicated and time-consuming. As different species of the analytes may give rise to specific voltammetric signals at distinctly different potentials, simple potential sensing has the specificity to detect different cellular species. By taking advantage of the different electrochemical characteristics of normal cells, cancer cells and biointeractions between anticancer drugs and cancer cells, we develop a specific, sensitive, direct, cost-effective and rapid method for the detection of cancer cells by electrochemical potential sensing based on Au/TiO2 nanobelt heterostructure electrodes that will be of significance in early cancer diagnosis, in vitro screening of anticancer drugs and molecular biology research.

  1. Few-layered MoS2 nanosheets wrapped ultrafine TiO2 nanobelts with enhanced photocatalytic property

    NASA Astrophysics Data System (ADS)

    Li, Haidong; Wang, Yana; Chen, Guohui; Sang, Yuanhua; Jiang, Huaidong; He, Jiating; Li, Xu; Liu, Hong

    2016-03-01

    Photocatalytic materials comprised of semiconductor nanostructures have attracted tremendous scientific and technological interest over the last 30 years. This is due to the fact that these photocatalytic materials have unique properties that allow for an effective direct energy transfer from light to highly reactive chemical species which are applicable in the remediation of environmental pollutants and photocatalytic hydrogen generation. Heterostructured photocatalysts are a promising type of photocatalyst which can combine the properties of different components to generate a synergic effect, resulting in a high photocatalytic activity. In this work, a heterostructured photocatalyst comprised of few-layered MoS2 nanosheets coated on a TiO2 nanobelts surface was synthesized through a simple hydrothermal treatment. The hybrid heterostructures with enhanced broad spectrum photocatalytic properties can harness UV and visible light energy to decompose organic contaminants in aqueous solutions as well as split water to hydrogen and oxygen. The mechanism of the enhancement is that the MoS2/TiO2 nanobelts heterostructure can enhance the separation of the photo-induced carriers, which results in a higher photocurrent due to the special electronic characteristics of the graphene-like layered MoS2 nanosheets. This methodology is potentially applicable to the synthesis of a range of hybrid nanostructures with promising applications in photocatalysis and other relevant areas.Photocatalytic materials comprised of semiconductor nanostructures have attracted tremendous scientific and technological interest over the last 30 years. This is due to the fact that these photocatalytic materials have unique properties that allow for an effective direct energy transfer from light to highly reactive chemical species which are applicable in the remediation of environmental pollutants and photocatalytic hydrogen generation. Heterostructured photocatalysts are a promising type of

  2. Physical model construction for electrical anisotropy of single crystal zinc oxide micro/nanobelt using finite element method

    SciTech Connect

    Yu, Guangbin; Tang, Chaolong; Song, Jinhui E-mail: wqlu@cigit.ac.cn; Lu, Wenqiang E-mail: wqlu@cigit.ac.cn

    2014-04-14

    Based on conductivity characterization of single crystal zinc oxide (ZnO) micro/nanobelt (MB/NB), we further investigate the physical mechanism of nonlinear intrinsic resistance-length characteristic using finite element method. By taking the same parameters used in experiment, a model of nonlinear anisotropic resistance change with single crystal MB/NB has been deduced, which matched the experiment characterization well. The nonlinear resistance-length comes from the different electron moving speed in various crystal planes. As the direct outcome, crystallography of the anisotropic semiconducting MB/NB has been identified, which could serve as a simple but effective method to identify crystal growth direction of single crystal semiconducting or conductive nanomaterial.

  3. Dimensional dependence of the dynamics of the Mn3d5 luminescence in (Zn, Mn)S nanowires and nanobelts

    NASA Astrophysics Data System (ADS)

    Chen, L.; Niebling, T.; Heimbrodt, W.; Stichtenoth, D.; Ronning, C.; Klar, P. J.

    2007-09-01

    ZnS nanostructures of different morphologies, i.e., nanowires and nanobelts, have been ion implanted with Mn and subsequently annealed to obtain Zn1-xMnxS nanostructures. The Mn content x was adjusted to lie in the range from 4×10-6% to 4% corresponding to a variation of the mean Mn-Mn distance between about 200 and 2nm , respectively. The Zn1-xMnxS nanowires have been studied by photoluminescence spectroscopy. The yellow Mn luminescence band indicates that the Mn2+ ions are incorporated on cation lattice sites replacing Zn. The temporal evolution of this internal Mn2+(3d5) luminescence is measured over 4 orders of magnitude in intensity. The decay behavior shows a clear dependence on the morphology of the nanostructure, in particular, on the ratio between the average Mn ion-killer center distance and the characteristic lateral size of the nanostructure. If the mean Mn-Mn distance is comparable to or smaller than the average Mn ion-killer center distance in the nanostructures, then concentration quenching of the Mn luminescence occurs similar to bulk. The nonexponential transients observed can be well described in the framework of a modified Förster model at reduced dimensionality. The photoluminescence (PL) behavior of the nanowires loses its one-dimensional character when the mean Mn ion-killer center distance becomes much smaller than the wire diameter. In contrast, the temporal PL behavior of the nanobelts is only purely two dimensional in this case and is of intermediate character between one dimensional and two dimensional otherwise.

  4. Suspending and Reinstating Joint Activities with Dialogue

    ERIC Educational Resources Information Center

    Chevalley, Eric; Bangerter, Adrian

    2010-01-01

    Interruptions are common in joint activities like conversations. Typically, interrupted participants suspend the activity, address the interruption, and then reinstate the activity. In conversation, people jointly commit to interact and to talk about a topic, establishing these commitments sequentially. When a commitment is suspended, face is…

  5. A novel 3D structure composed of strings of hierarchical TiO{sub 2} spheres formed on TiO{sub 2} nanobelts with high photocatalytic properties

    SciTech Connect

    Jiang, Yongjian; Li, Meicheng; Song, Dandan; Li, Xiaodan; Yu, Yue

    2014-03-15

    A novel hierarchical titanium dioxide (TiO{sub 2}) composite nanostructure with strings of anatase TiO{sub 2} hierarchical micro-spheres and rutile nanobelts framework (TiO{sub 2} HSN) is successfully synthesized via a one-step hydrothermal method. Particularly, the strings of hierarchical spheres are assembled by very thin TiO{sub 2} nanosheets, which are composed of highly crystallized anatase nanocrystals. Meanwhile, the HSN has a large surface area of 191 m{sup 2}/g, which is about 3 times larger than Degussa P25. More importantly, the photocatalytic activity of HSN and P25 were evaluated by the photocatalytic oxidation decomposition of methyl orange (MO) under UV light illumination, and the TiO{sub 2} HSN shows enhanced photocatalytic activity compared with Degussa P25, as result of its continuous hierarchical structures, special conductive channel and large specific surface area. With these features, the hierarchical TiO{sub 2} may have more potential applications in the fields of dye-sensitized solar cells and lithium ion batteries. -- Graphical abstract: Novel TiO{sub 2} with anatase micro-spheres and rutile nanobelts is synthesized. Enhanced photocatalysis is attributed to hierarchical structures (3D spheres), conductive channel (1D nanobelts) and large specific surface area (2D nanosheet). Highlights: • The novel TiO{sub 2} nanostructure (HSN) is fabricated for the first time. • HSN is composed of strings of anatase hierarchical spheres and rutile nanobelt. • HSN presents a larger S{sub BET} of 191 m{sup 2}/g, 3 times larger than the Degussa P25 (59 m{sup 2}/g). • HSN owns three kinds of dimensional TiO{sub 2} (1D, 2D and 3D) simultaneously. • HSN exhibits better photocatalytic performance compared with Degussa P25.

  6. Scrolling of Suspended CVD Graphene Sheets

    NASA Astrophysics Data System (ADS)

    Martynov, Oleg; Yeom, Sinchul; Bockrath, Marc; UC: Riverside Team

    Carbon Nanoscrolls, one dimensional spiral forms of graphitic carbon, have attracted recent interest due to their novel proposed properties. Although various production methods and studies of carbon nanoscrolls have been performed, low yield and poor controllability of their synthesis have slowed progress in this field. Suspended graphene membranes and carbon nanotubes have been predicted as promising systems for the formation of graphene scrolls. We have suspended chemical vapor deposition (CVD)-grown graphene over large holes in a Si/SiO2 substrate to make suspended membranes upon which nanotubes are placed. Initial experiments have been performed showing that tears or cuts of the suspended sheet can initiate scrolling. Our latest progress towards carbon nanotube initiated formation of graphene scrolls and suspended CVD graphene scrolling, along with measurements of these novel structures will be presented.

  7. Synthesis of few-layer MoS2 nanosheet-coated TiO2 nanobelt heterostructures for enhanced photocatalytic activities.

    PubMed

    Zhou, Weijia; Yin, Zongyou; Du, Yaping; Huang, Xiao; Zeng, Zhiyuan; Fan, Zhanxi; Liu, Hong; Wang, Jiyang; Zhang, Hua

    2013-01-14

    MoS(2) nanosheet-coated TiO(2) nanobelt heterostructures--referred to as TiO(2)@MoS(2)--with a 3D hierarchical configuration are prepared via a hydrothermal reaction. The TiO(2) nanobelts used as a synthetic template inhibit the growth of MoS(2) crystals along the c-axis, resulting in a few-layer MoS(2) nanosheet coating on the TiO(2) nanobelts. The as-prepared TiO(2)@MoS(2) heterostructure shows a high photocatalytic hydrogen production even without the Pt co-catalyst. Importantly, the TiO(2)@MoS(2) heterostructure with 50 wt% of MoS(2) exhibits the highest hydrogen production rate of 1.6 mmol h(-1) g(-1). Moreover, such a heterostructure possesses a strong adsorption ability towards organic dyes and shows high performance in photocatalytic degradation of the dye molecules.

  8. Enhanced sunlight photocatalytic activity of Ag3PO4 decorated novel combustion synthesis derived TiO2 nanobelts for dye and bacterial degradation.

    PubMed

    Eswar, Neerugatti KrishnaRao; Ramamurthy, Praveen Chandrashekarapura; Madras, Giridhar

    2015-07-01

    This study demonstrates the synthesis of TiO2 nanobelts using solution combustion derived TiO2 with enhanced photocatalytic activity for dye degradation and bacterial inactivation. Hydrothermal treatment of combustion synthesized TiO2 resulted in unique partially etched TiO2 nanobelts and Ag3PO4 was decorated using the co-precipitation method. The catalyst particles were characterized using X-ray diffraction analysis, BET surface area analysis, diffuse reflectance and electron microscopy. The photocatalytic properties of the composites of Ag3PO4 with pristine combustion synthesized TiO2 and commercial TiO2 under sunlight were compared. Therefore the studies conducted proved that the novel Ag3PO4/unique combustion synthesis derived TiO2 nanobelt composites exhibited extended light absorption, better charge transfer mechanism and higher generation of hydroxyl and hole radicals. These properties resulted in enhanced photodegradation of dyes and bacteria when compared to the commercial TiO2 nanocomposite. These findings have important implications in designing new photocatalysts for water purification.

  9. Catalyst-free growth of Al-doped SnO2 zigzag-nanobelts for low ppm detection of organic vapours

    NASA Astrophysics Data System (ADS)

    Sinha, Sudip Kumar; Ghosh, Saptarshi

    2016-10-01

    In this effort, we report on development of specific sensors dedicated for detection of two of these volatiles, namely ethanol and acetone, below the prescribed statutory limits. Single crystalline Al-doped SnO2 zigzag nanobelt structures were deposited on Si substrate by a catalyst-free thermal evaporation method. The Al-doped SnO2 zigzag nanostructures exhibit high sensitivity and repeatability together with coveted features like fast response and excellent stability. Structural attributes involving the crystal quality and morphology of Al-doped SnO2 zigzag nanobelts were analyzed using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy and transmission electron microscopy. The microscopic images revealed formation of randomly oriented 'zigzag-like' nanobelts with characteristic width between 60 nm and 200 nm and length of 50-300 μm. The Al-doping was observed to have a discerning effect in enhancing the sensitivity in comparison to the pristine nanowires by creating excess oxygen vacancies in the crystal lattice, confirmed through XPS and PL spectra.

  10. Solution phase synthesis of Na{sub 0.28}V{sub 2}O{sub 5} nanobelts into nanorings and the electrochemical performance in Li battery

    SciTech Connect

    Nagaraju, Ganganagappa; Chandrappa, Gujjarahalli Thimmanna

    2012-11-15

    Graphical abstract: Hydrothermal method has been adopted first time to prepare Na{sub 0.28}V{sub 2}O{sub 5} nanorings/nanobelts without using any organic surfactant/solvents at 130–160 °C for 1–2 days. TEM analyses reveal that the products consist of nanorings of width about 500 nm and thickness of about 100 nm with inner diameter of 5–7 m. Nanobelts of width 70–100 nm and several tens of micrometers in length are observed. The electrochemical results show that Na{sub 0.28}V{sub 2}O{sub 5} exhibits an initial discharge capacity of 320 mAh g{sup −1} and its capacity still retained 175 mAh g{sup −1} even after 69 cycles. Highlights: ► We are the first to report Na{sub 0.28}V{sub 2}O{sub 5} nanorings/nanobelts by solution method. ► Synthesis via hydrothermal method at 130–160 °C/1–2d in acidic medium. ► We have carried out without using any surfactant/templates/organic solvents. ► Shows discharge capacity of 320 mAh g{sup −1} and reach 175 mAh g{sup −1} after 69 cycles. ► A probable reaction mechanism for Na{sub 0.28}V{sub 2}O{sub 5} nanorings formation is also proposed. -- Abstract: In this paper, we are the first to report a simple one step hydrothermal method to synthesize Na{sub 0.28}V{sub 2}O{sub 5} nanorings/nanobelts without using any organic surfactant/solvents at 130–160 °C for 1–2 days. The obtained products have been characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, morphology by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and electrochemical discharge–charge test for lithium battery. XRD pattern exhibit a monoclinic Na{sub 0.28}V{sub 2}O{sub 5} structure. FTIR spectrum shows band at 958 cm{sup −1} is assigned to V=O stretching vibration, which is sensitive to intercalation and suggests that Na{sup +} ions are inserted between the vanadium oxide layers. TEM analyses reveal that the

  11. Numerical Modeling and Experimental Validation by Calorimetric Detection of Energetic Materials Using Thermal Bimorph Microcantilever Array: A Case Study on Sensing Vapors of Volatile Organic Compounds (VOCs).

    PubMed

    Kang, Seok-Won; Fragala, Joe; Banerjee, Debjyoti

    2015-01-01

    Bi-layer (Au-Si₃N₄) microcantilevers fabricated in an array were used to detect vapors of energetic materials such as explosives under ambient conditions. The changes in the bending response of each thermal bimorph (i.e., microcantilever) with changes in actuation currents were experimentally monitored by measuring the angle of the reflected ray from a laser source used to illuminate the gold nanocoating on the surface of silicon nitride microcantilevers in the absence and presence of a designated combustible species. Experiments were performed to determine the signature response of this nano-calorimeter platform for each explosive material considered for this study. Numerical modeling was performed to predict the bending response of the microcantilevers for various explosive materials, species concentrations, and actuation currents. The experimental validation of the numerical predictions demonstrated that in the presence of different explosive or combustible materials, the microcantilevers exhibited unique trends in their bending responses with increasing values of the actuation current. PMID:26334276

  12. Stability of suspended graphene under Casimir force

    NASA Astrophysics Data System (ADS)

    Chudnovsky, E. M.; Zarzuela, R.

    2016-08-01

    We consider a graphene sheet suspended above a conducting surface. Treating graphene as an elastic membrane subjected to Casimir force, we study its stability against sagging towards the conductor. There exists a critical elevation at the edges below which the central part of the suspended graphene nucleates a trunk that sinks under the action of the Casimir force. The dependence of the critical elevation on temperature, dimensions, and the elastic stress applied to the graphene sheet is computed.

  13. 7 CFR 61.37 - License may be suspended.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false License may be suspended. 61.37 Section 61.37... Cottonseed Samplers § 61.37 License may be suspended. The Director may, without a hearing, suspend or revoke... as to why his license should not be suspended or revoked. After the expiration of the aforesaid...

  14. 7 CFR 61.37 - License may be suspended.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false License may be suspended. 61.37 Section 61.37... Cottonseed Samplers § 61.37 License may be suspended. The Director may, without a hearing, suspend or revoke... as to why his license should not be suspended or revoked. After the expiration of the aforesaid...

  15. 7 CFR 61.37 - License may be suspended.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false License may be suspended. 61.37 Section 61.37... Cottonseed Samplers § 61.37 License may be suspended. The Director may, without a hearing, suspend or revoke... as to why his license should not be suspended or revoked. After the expiration of the aforesaid...

  16. 7 CFR 61.37 - License may be suspended.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false License may be suspended. 61.37 Section 61.37... Cottonseed Samplers § 61.37 License may be suspended. The Director may, without a hearing, suspend or revoke... as to why his license should not be suspended or revoked. After the expiration of the aforesaid...

  17. [Suspended particulates and lung health].

    PubMed

    Neuberger, Manfred; Moshammer, Hanns

    2004-01-01

    Based on several severe air pollution episodes, a temporal correlation between high concentrations of particulate matter (PM) and SO2 pollution and acute increases in respiratory and cardiopulmonary mortality had been established in Vienna for the 1970's. After air pollution had decreased in Austria in the 1980's--as documented by data on SO2, and total suspended particles (TSP)--no such associations between day-to-day changes of SO2 and TSP and mortality have been documented any more, however, traffic related pollutants like fine particles and NO2 remained a problem. Therefore, short term effects of PM on lung function, morbidity and mortality were investigated in Vienna, Linz, Graz and a rural control area. Long-term exposure and chronic disease--even more important for public health--were studied in repeated cross-sectional, a mixed longitudinal and a birth cohort study on school children in the city of Linz. Lung function growth was found impaired from long-term exposure to air pollutants and improved in districts where ambient air pollution had decreased. Where only TSP and SO2 had decreased, no continuous improvement of small airway function was found and end-expiratory flow rates stayed impaired where NO2-reduction from technical improvements of cars and industry was counterbalanced by increase of motorized (diesel) traffic. Remaining acute effects of ambient air pollution in 2001 from PM, NO2 and co-pollutants found in a time series study also show that continuing efforts are necessary. Active surface of particles inhaled several hours to days before spirometry was found related to short-term reductions in forced vital capacity-FVC (p<0.01), forced expiratory volume in one second-FEV1 (p<0.01) and maximal expiratory flow rate at 50% of vital capacity-MEF50 (p<0.05). In pupils with asthma or previous airway obstruction 4-week-diaries proved that the following symptoms increased with acute exposure to higher active surface of particles: wheezing (p<0

  18. Size and Temperature Dependence of Electron Transfer between CdSe Quantum Dots and a TiO 2 Nanobelt

    DOE PAGES

    Tafen, De Nyago; Prezhdo, Oleg V.

    2015-02-24

    Understanding charge transfer reactions between quantum dots (QD) and metal oxides is fundamental for improving photocatalytic, photovoltaic and electronic devices. The complexity of these processes makes it difficult to find an optimum QD size with rapid charge injection and low recombination. We combine time-domain density functional theory with nonadiabatic molecular dynamics to investigate the size and temperature dependence of the experimentally studied electron transfer and charge recombination at CdSe QD-TiO2 nanobelt (NB) interfaces. The electron injection rate shows strong dependence on the QD size, increasing for small QDs. The rate exhibits Arrhenius temperature dependence, with the activation energy of themore » order of millielectronvolts. The charge recombination process occurs due to coupling of the electronic subsystem to vibrational modes of the TiO2 NB. Inelastic electron-phonon scattering happens on a picosecond time scale, with strong dependence on the QD size. Our simulations demonstrate that the electron-hole recombination rate decreases significantly as the QD size increases, in excellent agreement with experiments. The temperature dependence of the charge recombination rates can be successfully modeled within the framework of the Marcus theory through optimization of the electronic coupling and the reorganization energy. Our simulations indicate that by varying the QD size, one can modulate the photoinduced charge separation and charge recombination, fundamental aspects of the design principles for high efficiency devices.« less

  19. Electrochemical preparation of MnO2 nanobelts through pulse base-electrogeneration and evaluation of their electrochemical performance

    NASA Astrophysics Data System (ADS)

    Aghazadeh, Mustafa; Maragheh, Mohammad Ghannadi; Ganjali, Mohammad Reza; Norouzi, Parviz; Faridbod, Farnoush

    2016-02-01

    Cathodic electrodeposition of MnO2 from a nitrate solution, via pulsed base (OH-) electrogeneration was performed for the first time. The deposition experiments were performed in a pulse current mode in typical on-times and off-times (i.e. ton = 1 s and toff = 1 s) with a peak current density of 2 mA cm-2 (Ia = 2 mA cm-2). The structural characterizations conducted by XRD and FTIR techniques revealed that the prepared MnO2 is composed of both α and γ phases. Morphological observation by SEM and TEM showed that the prepared MnO2 is made up of nanobelts with uniform shapes (an average diameter and length of 50 nm and 1 μm, respectively). Further electrochemical measurements by cyclic voltammetry and charge-discharge techniques revealed that the prepared MnO2 nanostructures have excellent capacitive behaviors, like a specific capacitance of 235.5 F g-1 and capacity retention of 91.3% after 1000 cycling at the scan rate of 25 mV s-1.

  20. Gold and gold-palladium alloy nanoparticles on heterostructured TiO2 nanobelts as plasmonic photocatalysts for benzyl alcohol oxidation

    NASA Astrophysics Data System (ADS)

    Jiang, Tongtong; Jia, Chuancheng; Zhang, Lanchun; He, Shuren; Sang, Yuanhua; Li, Haidong; Li, Yanqing; Xu, Xiaohong; Liu, Hong

    2014-11-01

    Plasmonic photocatalysts composed of Au and bimetallic Au-Pd alloy nanoparticles (NPs) on one-dimensional TiO2 nanobelts (TiO2-NBs) were used for the aerobic oxidation of benzyl alcohol under visible light irradiation. Remarkable light-promoted activity was observed for the as-synthesized M/TiO2-NB (M = Au, Au-Pd) nanostructures based on the TiO2(B)/anatase heterostructured nanobelt. The difference in band structure and the well matched interface between the TiO2(B) and anatase phases, coupled with the one-dimensional nanostructure, enable an enhanced charge transfer within the heterostructured nanobelt. This inter-phase charge transfer greatly facilitates the flow of hot electrons from the metal NPs to TiO2 and promotes benzyl alcohol oxidation. This efficient electron transfer was identified by the much higher photocurrent response measured for the Au/TiO2-NB nanostructure with the TiO2(B)/anatase heterojunction than those with either of the single phases under visible light irradiation. Alloying Au with Pd in Au-Pd/TiO2-NB results in a significant improvement in the visible light-promoted activity compared to the monometallic Au/TiO2-NB sample. It is supposed that the plasmon-mediated charge distribution within the alloy NPs is mainly responsible for the enhanced photocatalytic activity of the bimetallic nanostructures.Plasmonic photocatalysts composed of Au and bimetallic Au-Pd alloy nanoparticles (NPs) on one-dimensional TiO2 nanobelts (TiO2-NBs) were used for the aerobic oxidation of benzyl alcohol under visible light irradiation. Remarkable light-promoted activity was observed for the as-synthesized M/TiO2-NB (M = Au, Au-Pd) nanostructures based on the TiO2(B)/anatase heterostructured nanobelt. The difference in band structure and the well matched interface between the TiO2(B) and anatase phases, coupled with the one-dimensional nanostructure, enable an enhanced charge transfer within the heterostructured nanobelt. This inter-phase charge transfer greatly

  1. Suspended two-dimensional electron and hole gases

    SciTech Connect

    Kazazis, D.; Bourhis, E.; Gierak, J.; Gennser, U.; Bourgeois, O.; Antoni, T.

    2013-12-04

    We report on the fabrication of fully suspended two-dimensional electron and hole gases in III-V heterostructures. Low temperature transport measurements verify that the properties of the suspended gases are only slightly degraded with respect to the non-suspended gases. Focused ion beam technology is used to pattern suspended nanostructures with minimum damage from the ion beam, due to the small width of the suspended membrane.

  2. Pyroelectric-field driven defects diffusion along c-axis in ZnO nanobelts under high-energy electron beam irradiation

    SciTech Connect

    Ding, Yong Liu, Ying; Niu, Simiao; Wu, Wenzhuo; Wang, Zhong Lin

    2014-10-21

    When ZnO nanobelts are exposed to a high-dose electron probe of several nanometers to hundred nanometers in diameter inside a transmission electron microscope, due to the radiolysis effect, part of oxygen atoms will be ejected into the vacuum and leaving a Zn-ion rich surface with a pit appearance at both the electron-entrance and electron-exit surfaces. At the same time, a temperature distribution is created around the electron probe due to local beam heating effect, which generates a unidirectional pyroelectric field. This pyroelectric field is strong enough to drive Zn ions moving along its positive c-axis direction as interstitial ions. In the first case, for the ZnO nanobelts with c-axis lie in their large surfaces, defects due to the aggregation of Zn interstitial ions will be formed at some distances of 30–50 nm approximately along the c-axis direction from the electron beam illuminated area. Alternatively, for the ZnO nanobelts with ±(0001) planes as their large surfaces, the incident electron beam is along its c-axis and the generated pyroelectric field will drive the interstitial Zn-ions to aggregate at the Zn terminated (0001) surface where the local electrical potential is the lowest. Such electron beam induced damage in ZnO nanostructures is suggested as a result of Zn ion diffusion driven by the temperature gradient induced pyroelectric field along c-axis. Our study shows a radiation damage caused by electron beam in transmission electron microscopy, especially when the electron energy is high.

  3. X-38 Suspended in Hangar

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The X-38 lifting body research vehicle is shown here suspended in a hangar at NASA's Dryden Flight Research Center in 1998. The X-38 Crew Return Vehicle (CRV) research project is designed to develop the technology for a prototype emergency crew return vehicle, or lifeboat, for the International Space Station. The project is also intended to develop a crew return vehicle design that could be modified for other uses, such as a joint U.S. and international human spacecraft that could be launched on the French Ariane-5 Booster. The X-38 project is using available technology and off-the-shelf equipment to significantly decrease development costs. Original estimates to develop a capsule-type crew return vehicle were estimated at more than $2 billion. X-38 project officials have estimated that development costs for the X-38 concept will be approximately one quarter of the original estimate. Off-the-shelf technology is not necessarily 'old' technology. Many of the technologies being used in the X-38 project have never before been applied to a human-flight spacecraft. For example, the X-38 flight computer is commercial equipment currently used in aircraft and the flight software operating system is a commercial system already in use in many aerospace applications. The video equipment for the X-38 is existing equipment, some of which has already flown on the space shuttle for previous NASA experiments. The X-38's primary navigational equipment, the Inertial Navigation System/Global Positioning System, is a unit already in use on Navy fighters. The X-38 electromechanical actuators come from previous joint NASA, U.S. Air Force, and U.S. Navy research and development projects. Finally, an existing special coating developed by NASA will be used on the X-38 thermal tiles to make them more durable than those used on the space shuttles. The X-38 itself was an unpiloted lifting body designed at 80 percent of the size of a projected emergency crew return vehicle for the International

  4. Suspending superconducting qubits by silicon micromachining

    NASA Astrophysics Data System (ADS)

    Chu, Y.; Axline, C.; Wang, C.; Brecht, T.; Gao, Y. Y.; Frunzio, L.; Schoelkopf, R. J.

    2016-09-01

    We present a method for relieving aluminum 3D transmon qubits from a silicon substrate using micromachining. Our technique is a high yield, one-step deep reactive ion etch that requires no additional fabrication processes and results in the suspension of the junction area and edges of the aluminum film. The drastic change in the device geometry affects both the dielectric and the flux noise environment experienced by the qubit. In particular, the participation ratios of various dielectric interfaces are significantly modified, and suspended qubits exhibited longer T1's than non-suspended ones. We also find that the suspension increases the flux noise experienced by tunable SQUID-based qubits.

  5. Suspended polymer nanobridge on a quartz resonator

    NASA Astrophysics Data System (ADS)

    Yun, Minhyuk; Lee, Seongjae; Yim, Changyong; Jung, Namchul; Thundat, Thomas; Jeon, Sangmin

    2013-07-01

    A chemical vapor sensor based on a free-standing polystyrene (PS) nanofilm suspended between the tines of a quartz tuning fork (QTF) is demonstrated. Exposure to ethanol vapor decreased the modulus of the PS membrane, which resulted in a decrease in the resonance frequency of the QTF as a function of ethanol concentration. The suspended PS membrane structure on the QTF allowed gas molecules to diffuse into the membrane from both the top and bottom allowing faster response. The QTF response time was found to be 6.5 times faster than the response time of a conventional PS film-coated resonator sensor.

  6. 5 CFR 919.1010 - Suspending official.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Suspending official. 919.1010 Section 919.1010 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL SERVICE REGULATIONS (CONTINUED) GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) Definitions § 919.1010...

  7. 30 CFR 57.9317 - Suspended loads.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Suspended loads. 57.9317 Section 57.9317 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Loading, Hauling,...

  8. 30 CFR 57.9317 - Suspended loads.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Suspended loads. 57.9317 Section 57.9317 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Loading, Hauling,...

  9. 30 CFR 57.9317 - Suspended loads.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Suspended loads. 57.9317 Section 57.9317 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Loading, Hauling,...

  10. 30 CFR 57.9317 - Suspended loads.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Suspended loads. 57.9317 Section 57.9317 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Loading, Hauling,...

  11. 30 CFR 57.9317 - Suspended loads.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Suspended loads. 57.9317 Section 57.9317 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Loading, Hauling,...

  12. A Successful Retention Program for Suspended Students

    ERIC Educational Resources Information Center

    Dill, Anna L.; Gilbert, Jerome A.; Hill, Jennifer P.; Minchew, Sue S.; Sempier, Tracie A.

    2011-01-01

    Traditionally at Mississippi State University (MSU), students who are placed on academic suspension are required to stay out of school one regular semester. As an alternative, the university designed a program for early readmission for suspended students who agree to follow the requirements outlined in the "Learning Skills Support Program" (LSSP).…

  13. Suspended solids from industrial and municipal origins.

    PubMed

    Rosenwinkel, K H; Weichgrebe, D; Meyer, H; Wendler, D

    2001-10-01

    The origins of suspended solids are the effluents of municipal and industrial wastewater treatment plants and storm sewage treatment. This paper deals with the sources of industrial and municipal wastewater treatment and the single treatment of side streams. An overview of the common treatment processes is given and the main sinks for suspended solids are named and described. The food industry is based on the processing of organic matter (fruits, etc.). During the single processing steps three main fractions occur, inorganic material (e.g., from the washing step), organic residues (e.g., the peel), and suspended solids (SS) in the wastewater. Today higher rates of recycling (water and raw materials) can be found in all kinds of industrial processes. The principle is that avoidance should take precedence over utilization which should take precedence over disposal. Numerous possibilities of production-integrated measures exist, e.g., conveyance of production circuits, product recovery, and stepped cleaning. Despite and/or due to these efforts, huge amounts of residues occur. They are the main sink for suspended solids. Only seldom is landfilling used to treat these residues. Usually utilization as animal nourishment or biological (aerobic or anaerobic) or thermal (incineration) treatment methods are used. Huge capacities for a codigestion of agroindustrial residues (substrates) and wastewater sludge can be found in municipal digesters. As most of the food processing factories are indirect dischargers, the largest amount of the SS fraction in the wastewater is led to municipal wastewater treatment plants. Rarely, a connection between the SS concentrations in the influent and those in the effluent can be observed in conventional wastewater treatment. As a polishing step, filtration methods gain more and more importance with regard to suspended solids removal. PMID:11689029

  14. Suspended solids from industrial and municipal origins.

    PubMed

    Rosenwinkel, K H; Weichgrebe, D; Meyer, H; Wendler, D

    2001-10-01

    The origins of suspended solids are the effluents of municipal and industrial wastewater treatment plants and storm sewage treatment. This paper deals with the sources of industrial and municipal wastewater treatment and the single treatment of side streams. An overview of the common treatment processes is given and the main sinks for suspended solids are named and described. The food industry is based on the processing of organic matter (fruits, etc.). During the single processing steps three main fractions occur, inorganic material (e.g., from the washing step), organic residues (e.g., the peel), and suspended solids (SS) in the wastewater. Today higher rates of recycling (water and raw materials) can be found in all kinds of industrial processes. The principle is that avoidance should take precedence over utilization which should take precedence over disposal. Numerous possibilities of production-integrated measures exist, e.g., conveyance of production circuits, product recovery, and stepped cleaning. Despite and/or due to these efforts, huge amounts of residues occur. They are the main sink for suspended solids. Only seldom is landfilling used to treat these residues. Usually utilization as animal nourishment or biological (aerobic or anaerobic) or thermal (incineration) treatment methods are used. Huge capacities for a codigestion of agroindustrial residues (substrates) and wastewater sludge can be found in municipal digesters. As most of the food processing factories are indirect dischargers, the largest amount of the SS fraction in the wastewater is led to municipal wastewater treatment plants. Rarely, a connection between the SS concentrations in the influent and those in the effluent can be observed in conventional wastewater treatment. As a polishing step, filtration methods gain more and more importance with regard to suspended solids removal.

  15. Fabrication of BiOBr nanosheets@TiO2 nanobelts p-n junction photocatalysts for enhanced visible-light activity

    NASA Astrophysics Data System (ADS)

    Zhao, Yang; Huang, Xiang; Tan, Xin; Yu, Tao; Li, Xiangli; Yang, Libin; Wang, Shucong

    2016-03-01

    The construction of p-n junction structure is a smart strategy for improving the photocatalytic activity, since p-n junctions can inhibit the recombination of photo-induced charges. Herein, BiOBr nanosheets@TiO2 nanobelts p-n junction photocatalysts were prepared by assembling BiOBr nanosheets on the surface of TiO2 nanobelts via a hydrothermal route followed by a co-precipitation process. BiOBr@TiO2 p-n junction photocatalysts exhibited enhanced photocatalytic activity in photocatalytic H2 production over water splitting and photodegradation of Rhodamine B (RhB) under visible light irradiation. Mott-Schottky plots confirmed the formation of p-n junctions in the interface of BiOBr and TiO2. The enhanced photocatalytic performance can be ascribed to the 1D nanostructure and the formation of p-n junctions. This work shows a potential application of low cost BiOBr as a substitute for noble metals in photocatalytic H2 production under visible light irradiation.

  16. N-Doped TiO2 Nanobelts with Coexposed (001) and (101) Facets and Their Highly Efficient Visible-Light-Driven Photocatalytic Hydrogen Production.

    PubMed

    Sun, Shuchao; Gao, Peng; Yang, Yurong; Yang, Piaoping; Chen, Yujin; Wang, Yanbo

    2016-07-20

    To narrow the band gap (3.2 eV) of TiO2 and extend its practical applicability under sunlight, the doping with nonmetal elements has been used to tune TiO2 electronic structure. However, the doping also brings new recombination centers among the photoinduced charge carriers, which results in a quantum efficiency loss accordingly. It has been proved that the {101} facets of anatase TiO2 are beneficial to generating and transmitting more reductive electrons to promote the H2-evolution in the photoreduction reaction, and the {001} facets exhibit a higher photoreactivity to accelerate the reaction involved of photogenerated hole. Thus, it was considered by us that using the surface heterojunction composed of both {001} and {101} facets may depress the disadvantage of N doping. Fortunately, we successfully synthesized anatase N-doped TiO2 nanobelts with a surface heterojunction of coexposed (101) and (001) facets. As expected, it realized the charge pairs' spatial separation and showed higher photocatalytic activity under a visible-light ray: a hydrogen generation rate of 670 μmol h(-1) g(-1) (much higher than others reported previously in literature of N-doped TiO2 nanobelts).

  17. Synergistic effect of nanocavities in anatase TiO2 nanobelts for photocatalytic degradation of methyl orange dye in aqueous solution.

    PubMed

    Praveen Kumar, D; Lakshmana Reddy, N; Karthikeyan, M; Chinnaiah, N; Bramhaiah, V; Durga Kumari, V; Shankar, M V

    2016-09-01

    Nanocavities are empty voids exposed on the surface of one dimensional TiO2 nanostructured material. Often, they exhibited beneficial optical and electrical properties that leads to efficient photocatalytic reactions. This study reports formation of nanocavities on anatase TiO2 nanobelts (TNB) through dehydroxylation of surface hydroxyl groups during calcination process (350-600°C). The morphological and crystal structure analysis of TNB-500, -550 and -600 displayed the nanobelts shape with high density of nano-size cavities and increase in average diameter with calcination temperature. The SAED patterns confirm the anatase TiO2 phase. The enhanced light absorption properties of biphasic anatase/TiO2-B and anatase TiO2 than H2Ti3O7 are attributed to transformation of crystal structure upon calcination process. The catalytic activity was evaluated for degradation of methyl orange dye in aqueous solution under solar light irradiation. The reaction variables such as calcination temperature, amount of catalyst and pH of the methyl orange dye solution were studied and discussed in detail. Under optimal experimental conditions TNB-550 photocatalyst displayed highest degradation performance about 8 folds higher than H2Ti3O7. The high performance is explained as due to synergistic properties of one dimensional anatase TiO2 with high density of nanocavities leading to one dimensional transfer of electrons and high absorption co-efficient in UV-A spectrum are suitable for efficient red-ox reactions.

  18. The loading of coordination complex modified polyoxometalate nanobelts on activated carbon fiber: a feasible strategy to obtain visible light active and highly efficient polyoxometalate based photocatalysts.

    PubMed

    Lu, Tingting; Xu, Xinxin; Li, Huili; Li, Zhenyu; Zhang, Xia; Ou, Jinzhao; Mei, Mingliang

    2015-02-01

    To enhance the photocatalytic properties of coordination complex modified polyoxometalates (CC/POMs) in the visible light region, its nanobelts (CC/POMNBs) were loaded on activated carbon fiber (ACF) through a simple colloidal blending process. The resulting coordination complex modified polyoxometalate nanobelts loaded activated carbon fiber composite materials (CC/POMNBs/ACF) exhibited dramatic photocatalytic activity for the degradation of rhodamine B (RhB) under visible light irradiation. Optical and electrochemical methods illustrated the enhanced photocatalytic activity of CC/POMNBs/ACF, which originates from the high separation efficiency of the photogenerated electrons and holes on the interface of the CC/POMNBs and ACF, which results from the synergistic effects between them. In the composite material, the role of ACF could be described as a photosensitizer and a good electron transporter. Furthermore, the influence of the mass ratio between the CC/POMNBs and ACF on the photocatalytic performance of the resulting composite material was discussed, and an ideal value to obtain highly efficient photocatalysts was obtained. The results suggested that the loading of CC/POMNBs on the surface of ACF would be a feasible strategy to enhance their photocatalytic activity.

  19. Synergistic effect of nanocavities in anatase TiO2 nanobelts for photocatalytic degradation of methyl orange dye in aqueous solution.

    PubMed

    Praveen Kumar, D; Lakshmana Reddy, N; Karthikeyan, M; Chinnaiah, N; Bramhaiah, V; Durga Kumari, V; Shankar, M V

    2016-09-01

    Nanocavities are empty voids exposed on the surface of one dimensional TiO2 nanostructured material. Often, they exhibited beneficial optical and electrical properties that leads to efficient photocatalytic reactions. This study reports formation of nanocavities on anatase TiO2 nanobelts (TNB) through dehydroxylation of surface hydroxyl groups during calcination process (350-600°C). The morphological and crystal structure analysis of TNB-500, -550 and -600 displayed the nanobelts shape with high density of nano-size cavities and increase in average diameter with calcination temperature. The SAED patterns confirm the anatase TiO2 phase. The enhanced light absorption properties of biphasic anatase/TiO2-B and anatase TiO2 than H2Ti3O7 are attributed to transformation of crystal structure upon calcination process. The catalytic activity was evaluated for degradation of methyl orange dye in aqueous solution under solar light irradiation. The reaction variables such as calcination temperature, amount of catalyst and pH of the methyl orange dye solution were studied and discussed in detail. Under optimal experimental conditions TNB-550 photocatalyst displayed highest degradation performance about 8 folds higher than H2Ti3O7. The high performance is explained as due to synergistic properties of one dimensional anatase TiO2 with high density of nanocavities leading to one dimensional transfer of electrons and high absorption co-efficient in UV-A spectrum are suitable for efficient red-ox reactions. PMID:27289430

  20. Graphene oxide coated coordination polymer nanobelt composite material: a new type of visible light active and highly efficient photocatalyst for Cr(VI) reduction.

    PubMed

    Shi, Gui-Mei; Zhang, Bin; Xu, Xin-Xin; Fu, Yan-Hong

    2015-06-28

    A visible light active photocatalyst was synthesized successfully by coating graphene oxide (GO) on a coordination polymer nanobelt (CPNB) using a simple colloidal blending process. Compared with neat CPNB, the resulting graphene oxide coated coordination polymer nanobelt composite material (GO/CPNB) exhibits excellent photocatalytic efficiency in the reduction of K2Cr2O7 under visible light irradiation. In the composite material, GO performs two functions. Firstly, it cuts down the band gap (E(g)) of the photocatalyst and extends its photoresponse region from the ultraviolet to visible light region. Secondly, GO exhibits excellent electron transportation ability that impedes its recombination with holes, and this can enhance photocatalytic efficiency. For GO, on its surface, the number of functional groups has a great influence on the photocatalytic performance of the resulting GO/CPNB composite material and an ideal GO"coater" to obtain a highly efficient GO/CPNB photocatalyst has been obtained. As a photocatalyst that may be used in the treatment of Cr(VI) in wastewater, GO/CPNB exhibited outstanding stability during the reduction of this pollutant.

  1. Loading of a coordination polymer nanobelt on a functional carbon fiber: a feasible strategy for visible-light-active and highly efficient coordination-polymer-based photocatalysts.

    PubMed

    Xu, Xin-Xin; Yang, Hong-Yu; Li, Zhen-Yu; Liu, Xiao-Xia; Wang, Xiu-Li

    2015-02-23

    To improve the photocatalytic properties of coordination polymers under irradiation in the visible-light region, coordination polymer nanobelts (CPNB) were loaded on functional carbon fiber (FCF) through the use of a simple colloidal blending process. The resulting coordination polymer nanobelt loaded functional carbon fiber composite material (CPNB/FCF) exhibited dramatically improved photocatalytic activity for the degradation of rhodamine B (RhB) under visible-light irradiation. Optical and electrochemical methods illustrated the enhanced photocatalytic activity of CPNB/FCF originated from high separation efficiency of photogenerated electrons and holes on the interface of CPNB and FCF, which was produced by the synergy effect between them. In the composite material, the role of FCF could be described as photosensitizer and good electron transporter. For FCF, the number of functional groups on its surface has a significant influence on the photocatalytic performance of the resulting CPNB/FCF composite material, and an ideal FCF carrier was obtained as a highly efficient CPNB/FCF photocatalyst. CPNB/FCF showed outstanding stability during the degradation of rhodamine B (RhB); thus, the material is suitable for use as a photocatalyst in the treatment of organic dyes in water.

  2. MoS2 coating on MoO3 nanobelts: A novel approach for a high specific charge electrode for rechargeable Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Villevieille, Claire; Wang, Xiao-Jun; Krumeich, Frank; Nesper, Reinhard; Novák, Petr

    2015-04-01

    The electrochemical properties of MoS2 coated MoO3 nanobelts in lithium-ion batteries were investigated. A thin layer of MoS2 was coated on the nanobelts of MoO3 successfully through a facile sulfur transfer method, and the X-ray synchrotron diffraction revealed the crystallographic features of this composite material. The specific charge of the coated sample was beyond 1100 Ah/kg (at 1C rate) and 1400 Ah/kg at C/10 rate when tested in the 0.05 V-3.5 V vs. Li+/Li range. It was found that, with coating the Coulombic efficiency was higher than 98% which indicates a highly reversible process. Additionally, the electrochemical reaction and the degradation mechanism were studied by in situ X-ray synchrotron diffraction (1st and 50th cycle), and by post mortem SEM analysis. Both revealed a structural degradation as well as a surface degradation of the electrode by means of a thick amorphous layer on the surface of the active material.

  3. Numerical Modeling and Experimental Validation by Calorimetric Detection of Energetic Materials Using Thermal Bimorph Microcantilever Array: A Case Study on Sensing Vapors of Volatile Organic Compounds (VOCs)

    PubMed Central

    Kang, Seok-Won; Fragala, Joe; Banerjee, Debjyoti

    2015-01-01

    Bi-layer (Au-Si3N4) microcantilevers fabricated in an array were used to detect vapors of energetic materials such as explosives under ambient conditions. The changes in the bending response of each thermal bimorph (i.e., microcantilever) with changes in actuation currents were experimentally monitored by measuring the angle of the reflected ray from a laser source used to illuminate the gold nanocoating on the surface of silicon nitride microcantilevers in the absence and presence of a designated combustible species. Experiments were performed to determine the signature response of this nano-calorimeter platform for each explosive material considered for this study. Numerical modeling was performed to predict the bending response of the microcantilevers for various explosive materials, species concentrations, and actuation currents. The experimental validation of the numerical predictions demonstrated that in the presence of different explosive or combustible materials, the microcantilevers exhibited unique trends in their bending responses with increasing values of the actuation current. PMID:26334276

  4. Modeling Total Suspended Solids (TSS) Concentrations in Narragansett Bay.

    EPA Science Inventory

    This work covers mechanistic modeling of suspended particulates in estuarine systems with an application to Narragansett Bay, RI. Suspended particles directly affect water clarity and attenuate light in the water column. Water clarity affects both phytoplankton and submerged aqua...

  5. 17. Truss suspended column, industrial loft building, looking at southeast ...

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

    17. Truss suspended column, industrial loft building, looking at southeast corner. Note open floor plan as a result of the floor beams being suspended from above. - Dry Dock Engine Works, 1801 Atwater Street, Detroit, MI

  6. 40 CFR 230.21 - Suspended particulates/turbidity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... suspended particulates persist. The biological and the chemical content of the suspended material may react..., pathogens, and viruses absorbed or adsorbed to fine-grained particulates in the material may become... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Suspended particulates/turbidity....

  7. Thermoacoustic transduction in individual suspended carbon nanotubes.

    PubMed

    Mason, Blake J; Chang, Shun-Wen; Chen, Jihan; Cronin, Stephen B; Bushmaker, Adam W

    2015-05-26

    We report an experimental measurement of the acoustic signal emitted from an individual suspended carbon nanotube (CNT) approximate 2 μm in length, 1 nm in diameter, and 10(-21) kg in mass. This system represents the smallest thermoacoustic system studied to date. By applying an AC voltage of 1.4 V at 8 kHz to the suspended CNT, we are able to detect the acoustic signal using a commercial microphone. The acoustic power detected is found to span a range from 0.1 to 2.4 attoWatts or 0.2 to 1 μPa of sound pressure. This corresponds to thermoacoustic efficiencies ranging from 0.007 to 0.6 Pa/W for the seven devices that were measured in this study. Here, the small lateral dimensions of these devices cause large heat losses due to thermal conduction, which result in the relatively small observed thermoacoustic efficiencies. PMID:25961803

  8. Molybdenum-rhenium superconducting suspended nanostructures

    SciTech Connect

    Aziz, Mohsin; Christopher Hudson, David; Russo, Saverio

    2014-06-09

    Suspended superconducting nanostructures of MoRe 50%/50% by weight are fabricated employing commonly used fabrication steps in micro- and nano-meter scale devices followed by wet-etching with Hydro-fluoric acid of a SiO{sub 2} sacrificial layer. Suspended superconducting channels as narrow as 50 nm and length 3 μm have a critical temperature of ≈6.5 K, which can increase by 0.5 K upon annealing at 400 °C. A detailed study of the dependence of the superconducting critical current and critical temperature upon annealing and in devices with different channel widths reveals that desorption of contaminants is responsible for the improved superconducting properties. These findings pave the way for the development of superconducting electromechanical devices using standard fabrication techniques.

  9. Characterization of suspended particles in Everglades wetlands

    USGS Publications Warehouse

    Noe, G.B.; Harvey, J.W.; Saiers, J.E.

    2007-01-01

    We report the concentration, phosphorus (P) and nitrogen (N) content, and size and chemical fractionation of fine suspended particles (0.2-100 ??m) and colloids (3 kilodalton [kDa]-0.1 ??m) in the surface water of Everglades wetlands along regional and P-enrichment gradients. Total suspended sediment concentrations ranged from 0.7 to 2.7 mg L-1. Total particulate P concentrations increased from 0.05 ??mol L-1 to 0.31 ??mol L -1 along the P-enrichment gradient. Particles contained from 20% to 43% of total P but <12% of total N in surface water. Dissolved (<0.2 ??m) organic N contained about 90% of total N, with the 3-100-kDa colloidal size class containing the most N of any size class. The 0.45-2.7-??m size fraction held the most particulate P at all sites, whereas particulate N was most abundant in the 2.7-10-??m size class at most sites. Standard chemical fractionation of particles identified acid-hydrolyzable P as the most abundant species of particulate P, with little reactive or refractory organic P. Sequential chemical extraction revealed that about 65% of total particulate P was microbial, while about 25% was associated with humic and fulvic organic matter. The size and chemical fractionation information suggested that P-rich particles mostly consisted of suspended bacteria. Suspended particles in Everglades wetlands were small in size and had low concentrations, yet they stored a large proportion of surface-water P in intermediately reactive forms, but they held little N. ?? 2007, by the American Society of Limnology and Oceanography, Inc.

  10. Suspended Sediment Monitoring Strategies Reduce Model Uncertainties

    NASA Astrophysics Data System (ADS)

    Eads, R.; O'Connor, M.

    2007-12-01

    Regulatory agencies require development and implementation of Total Maximum Daily Loads for watersheds listed under section 303d of the Clean Water Act. For rivers identified as sediment impaired, methods are required to identify sediment sources and to estimate loading capacities, and models, such as sediment budgets, are often employed. Models can be tested and improved when stream monitoring provides accurate estimates of sediment loads. Motivated by proposed vineyard development on forested ridges in a sediment-listed watershed in the Coast Range of northern California, four tributaries to Gualala River ranging in size from 300 to 800 ha2 were monitored over two winter seasons. More than 1850 samples were analyzed for suspended sediment concentration. Inter- annual variability of sediment loads from wet and dry years is compared. Traditional methods for estimating suspended sediment loads often rely on measurements, such as water discharge, that are not well correlated to sediment concentration due to the highly variable routing of sediment to the channel from hillslopes, roads, and landslides. A method, such as Turbidity Threshold Sampling, that employs a parameter well correlated to suspended sediment concentration can improve sampling efficiency by collecting samples that are distributed over a range of rising and falling concentrations. The resulting set of samples can be used to estimate sediment loads by establishing a relationship between concentration and turbidity for any sampled period and applying it to the continuous turbidity record.

  11. Suspended sediments limit coral sperm availability.

    PubMed

    Ricardo, Gerard F; Jones, Ross J; Clode, Peta L; Humanes, Adriana; Negri, Andrew P

    2015-01-01

    Suspended sediment from dredging activities and natural resuspension events represent a risk to the reproductive processes of coral, and therefore the ongoing maintenance of reefal populations. To investigate the underlying mechanisms that could reduce the fertilisation success in turbid water, we conducted several experiments exposing gametes of the corals Acropora tenuis and A. millepora to two sediment types. Sperm limitation was identified in the presence of siliciclastic sediment (230 and ~700 mg L(-1)), with 2-37 fold more sperm required to achieve maximum fertilisation rates, when compared with sediment-free treatments. This effect was more pronounced at sub-optimum sperm concentrations. Considerable (>45%) decreases in sperm concentration at the water's surface was recorded in the presence of siliciclastic sediment and a >20% decrease for carbonate sediment. Electron microscopy then confirmed sediment entangled sperm and we propose entrapment and sinking is the primary mechanism reducing sperm available to the egg. Longer exposure to suspended sediments and gamete aging further decreased fertilisation success when compared with a shorter exposure. Collectively, these findings demonstrate that high concentrations of suspended sediments effectively remove sperm from the water's surface during coral spawning events, reducing the window for fertilisation with potential subsequent flow-on effects for recruitment. PMID:26659008

  12. Freely Suspended Smectic Films in Aqueous Environment

    NASA Astrophysics Data System (ADS)

    Peddireddy, Karthik; Bahr, Christian

    2012-02-01

    Smectic liquid crystals easily form thin films which are freely suspended on a solid frame in air. These systems have been thoroughly studied for various purposes such as structural studies of smectic phases, investigating phase transitions in two-dimensional systems, and studying various physical properties of liquid crystals. In the present study, we explore the preparation of freely suspended smectic films in water. A prerequisite is the presence of a surfactant which accumulates at the liquid-crystal/water interface and induces a homeotropic anchoring of the director, so that the smectic layers align parallel to the two film surfaces. The presence of the surfactant might also serve as a handle to tune properties such as the surface tension of the films (which is hardly possible for freely suspended films in air). We study the formation of films in water using different frames and different surfactants, and we focus especially on the thinning behaviour which occurs when the temperature is increased towards the smectic - nematic or smectic - isotropic transition.

  13. Suspended sediments limit coral sperm availability

    PubMed Central

    Ricardo, Gerard F.; Jones, Ross J.; Clode, Peta L.; Humanes, Adriana; Negri, Andrew P.

    2015-01-01

    Suspended sediment from dredging activities and natural resuspension events represent a risk to the reproductive processes of coral, and therefore the ongoing maintenance of reefal populations. To investigate the underlying mechanisms that could reduce the fertilisation success in turbid water, we conducted several experiments exposing gametes of the corals Acropora tenuis and A. millepora to two sediment types. Sperm limitation was identified in the presence of siliciclastic sediment (230 and ~700 mg L−1), with 2–37 fold more sperm required to achieve maximum fertilisation rates, when compared with sediment-free treatments. This effect was more pronounced at sub-optimum sperm concentrations. Considerable (>45%) decreases in sperm concentration at the water’s surface was recorded in the presence of siliciclastic sediment and a >20% decrease for carbonate sediment. Electron microscopy then confirmed sediment entangled sperm and we propose entrapment and sinking is the primary mechanism reducing sperm available to the egg. Longer exposure to suspended sediments and gamete aging further decreased fertilisation success when compared with a shorter exposure. Collectively, these findings demonstrate that high concentrations of suspended sediments effectively remove sperm from the water’s surface during coral spawning events, reducing the window for fertilisation with potential subsequent flow-on effects for recruitment. PMID:26659008

  14. Transient dehydration of lungs in tail-suspended rats

    NASA Technical Reports Server (NTRS)

    Hargens, A. R.; Steskal, J.; Morey-Holton, E. R.

    1985-01-01

    The fluid balance in the lungs of rats exposed to head-down tilt is examined. Six Munich-Wister rats were suspended for 7 days and 10 Sprague-Dawley rats for 14 days using the technique of Morey (1979). The water contents of the lungs of the suspended and a control group are calculated and compared. The data reveal that the two-days suspended rats had dehydrated lungs; however, the lungs of the 14-day suspended and control group rats were similar. It is noted that the dehydration in the 2-day suspended rats is caused by general dehydration not the head-tilt position.

  15. Probability forecast of the suspended sediment concentration using copula

    NASA Astrophysics Data System (ADS)

    Yu, Kun-xia; Li, Peng; Li, Zhanbin

    2016-04-01

    An approach for probability forecast of the suspended sediment loads is presented in our research. Probability forecast model is established based on the joint probability distribution of water discharge and suspended sediment concentration. The conditional distribution function of suspended sediment concentration given water discharge is evaluated provided the joint probability distribution between water discharge and suspended sediment concentration is constructed, and probability forecast of suspended sediment concentration is implemented in terms of conditional probability function. This approach is exemplified using annual data set of ten watersheds in the middle Yellow River which is characterized by heavy sediment. The three-parameter Gamma distribution is employed to fit the marginal distribution of annual water discharge and annual suspended sediment concentration, and the Gumbel copula can well describe the dependence structure between annual water discharge and annual suspended sediment concentration. Annual suspended sediment concentration estimated from the conditional distribution function with forecast probability of 50 percent agree better with the observed suspended sediment concentration values than the traditional sediment rating curve method given water discharge values. The overwhelming majority of observed suspended sediment concentration points lie between the forecast probability of 5 percent and 95 percent, which can be considered as the lower and upper 95th percent uncertainty bound of the predicted observation respectively. The results indicate that probability forecast on the basis of conditional distribution function is a potential alternative in suspended sediment and other hydrological variables estimation.

  16. Intrinsic non-ohmic electronic transport properties of the transparent In-Zn-O compound nanobelts under ohmic contact and out of the space charge limited transport region.

    PubMed

    Wen, Jing; Zhang, Xitian; Gao, Hong

    2016-02-19

    It is generally accepted that the nonlinear I-V characteristics for semiconductor nanostructures are mainly induced by the Schottky contacts or by the space charge limited transport mechanism. We perform I-V measurements on undoped and doped In-Zn-O compound nanobelts and confirm that their intrinsic non-ohmic transport behaviors are not caused by these mechanisms. A model based on the hopping assisted trap state electrons transport process is introduced to explain the nonlinear I-V characteristics and to extract their electrical parameters. An understanding of this trap-state influenced carrier transport can advance the progress of nanomaterials applications and enable us to distinguish their intrinsic transport behaviors from contact effects. The results also indicate that the material has good electrical properties and can be used as a potential substitute for In2O3.

  17. Desorption of pyrethroids from suspended solids.

    PubMed

    Fojut, Tessa L; Young, Thomas M

    2011-08-01

    Pyrethroid insecticides have been widely detected in sediments at concentrations that can cause toxicity to aquatic organisms. Desorption rates play an important role in determining the bioavailability of hydrophobic organic compounds, such as pyrethroids, because these compounds are more likely to be sorbed to solids in the environment, and times to reach sorptive equilibrium can be long. In the present study, sequential Tenax desorption experiments were performed with three sorbents, three aging times, and four pyrethroids. A biphasic rate model was fit to the desorption data with r(2)  > 0.99, and the rapid and slow compartment desorption rate constants and compartment fractions are reported. Suspended solids from irrigation runoff water collected from a field that had been sprayed with permethrin 1 d before were used in the experiments to compare desorption rates for field-applied pyrethroids with those for laboratory-spiked materials. Suspended solids were used in desorption experiments because suspended solids can be a key source of hydrophobic compounds in surface waters. The rapid desorption rate parameters of field-applied permethrin were not statistically different from those of laboratory spiked permethrin, indicating that desorption of the spiked pyrethroids is comparable to desorption of the pyrethroids added and aged in the field. Sorbent characteristics had the greatest effect on desorption rate parameters; as organic carbon content of the solids increased, the rapid desorption fractions and rapid desorption rate constants both decreased. The desorption rate constant of the slow compartment for sediment containing permethrin aged for 28 d was significantly different compared to aging for 1 d and 7 d, whereas desorption in the rapid and slow compartments did not differ between these treatments.

  18. Monitoring of suspended sediment in South Tyrol

    NASA Astrophysics Data System (ADS)

    Nadalet, Rudi; Dinale, Roberto; Pernter, Martin; Maraldo, Luca; Peterlin, Dieter; Richter, Arnold; Comiti, Francesco

    2016-04-01

    In the context of the EU Water Framework Directive (WFD), which aims to achieve a good status of European water bodies, the Hydrographic Office of the Autonomous Province of Bolzano (Italy) extended in 2014 its institutional activities including the monitoring of suspended sediment in the river channel network. Currently, the only active monitoring station is on the Adige River at the gauging station of Ponte Adige near Bolzano (drainage area 2705 km2). The applied monitoring strategy and the data analysis concept are both based on the guidelines issued by the Austrian Federal Ministry of Agriculture, Forestry, Environment and Water Management (BMLFUW). The results indicates that the temporal variability strongly differs during the investigated period (2014-2015). In addition to the analysis of precipitation and water discharge, temperature and lightning activity were also included to better understand the sediment transport dynamics observed at the station. In summer 2015, the combination of constantly high daily temperature throughout the Adige basin (which drove intense glacier melting in the headwaters) with a high frequency of convective rainfall events (90% more than in 2014, obtained through lightning detection), led to an annual mass of transported suspended sediment of 260000 t. Interestingly, this value is similar to the one estimated for 2014 (300000 t), which was characterized by very different meteorological conditions (colder and wetter summer), but with the occurrence of an important flood in August, which transported half of the annual amount. Finally, we can conclude that the adopted monitoring strategy is applicable for institutional aims in terms of costs as well as in terms of time effort. During the next years, other stations for suspended sediment monitoring are planned to be installed in the Province to cover the most important river segments.

  19. Mechanical Fluidity of Fully Suspended Biological Cells

    PubMed Central

    Maloney, John M.; Lehnhardt, Eric; Long, Alexandra F.; Van Vliet, Krystyn J.

    2013-01-01

    Mechanical characteristics of single biological cells are used to identify and possibly leverage interesting differences among cells or cell populations. Fluidity—hysteresivity normalized to the extremes of an elastic solid or a viscous liquid—can be extracted from, and compared among, multiple rheological measurements of cells: creep compliance versus time, complex modulus versus frequency, and phase lag versus frequency. With multiple strategies available for acquisition of this nondimensional property, fluidity may serve as a useful and robust parameter for distinguishing cell populations, and for understanding the physical origins of deformability in soft matter. Here, for three disparate eukaryotic cell types deformed in the suspended state via optical stretching, we examine the dependence of fluidity on chemical and environmental influences at a timescale of ∼1 s. We find that fluidity estimates are consistent in the time and frequency domains under a structural damping (power-law or fractional-derivative) model, but not under an equivalent-complexity, lumped-component (spring-dashpot) model; the latter predicts spurious time constants. Although fluidity is suppressed by chemical cross-linking, we find that ATP depletion in the cell does not measurably alter the parameter, and we thus conclude that active ATP-driven events are not a crucial enabler of fluidity during linear viscoelastic deformation of a suspended cell. Finally, by using the capacity of optical stretching to produce near-instantaneous increases in cell temperature, we establish that fluidity increases with temperature—now measured in a fully suspended, sortable cell without the complicating factor of cell-substratum adhesion. PMID:24138852

  20. Development of a magnetically suspended momentum wheel

    NASA Technical Reports Server (NTRS)

    Hamilton, S. B.

    1973-01-01

    An engineering model of a magnetically suspended momentum wheel was designed, fabricated, and tested under laboratory conditions. The basic unit consisted of two magnet bearings, a sculptured aluminum rotor, brushless dc spin motor, and electronics. The magnet bearings, utilizing rare-earth cobltrat-samarium magnets were active radially and passive axially. The results of the program showed that momentum wheels with magnetic bearings are feasible and operable, and that magnetic bearings of this type are capable of being used for applications where high capacity, high stiffness, and low power consumption are required. The tests performed developed criteria for improved performance for future designs.

  1. Suspended substrate stripline filters for ESM applications

    NASA Astrophysics Data System (ADS)

    Dean, J. E.

    1985-07-01

    Multi-octave contiguous channel multiplexers are a key component in EW systems, since they provide the front-end signal sorting. The paper describes advances in the development of broadband, low-loss, selective, lowpass, highpass and bandpass filters and contiguous channel multiplexers from 500 MHz to 26.5 GHz, in the form of suspended substrate stripline (SSS) realizations, in particular to increased bandwidth/channel and increased band-edge selectivity. The paper also discusses a novel range of low-loss, selective, broadband filters, recently designed using lumped-element technology to provide a high performance over 20 MHz to 1.5 GHz.

  2. Oscillation damped movement of suspended objects

    SciTech Connect

    Jones, J.F.; Petterson, B.J.

    1988-01-01

    Transportation of objects using overhead cranes or manipulators can induce pendulum motion of the object. Residual oscillation from transportation typically must be damped or allowed to decay before the next process can take place. By properly programming the acceleration of the transporting device (e.g., crane) an oscillation damped transport and swing free stop is obtainable. This paper reviews the theory associated with oscillation damped trajectories for simply suspended objects and describes a particular implementation using a CIMCORP XR 6100 gantry robot. 8 refs., 7 figs., 1 tab.

  3. Electronic thermal conductivity of suspended graphene

    SciTech Connect

    Begum, K. Rizwana Sankeshwar, N. S.

    2014-04-24

    Electronic thermal conductivity, κ{sub e}, of suspended graphene is studied for 20K 100K, becoming dominant for T > 250K. Good agreement with recent experimental data is obtained.

  4. A comparison of load estimates using total suspended solids and suspended-sediment concentration data

    USGS Publications Warehouse

    Glysson, G.D.; Gray, J.R.; Schwarz, G.E.

    2001-01-01

    This paper presents the results to-date from a continuing investigation into the differences between total suspended solids (TSS) and suspended-sediment concentration (SSC) data and the ramifications of using each type of data to estimate sediment loads. It compares estimates of annual suspended-sediment loads that were made using regression equations developed from paired TSS and SSC data, to annual loads computed by the U.S. Geological Survey (USGS) using traditional techniques and SSC data. Load estimates were compared for 10 stations where sufficient TSS and SSC paired data were available to develop sediment-transport curves for the same time period that daily suspended-sediment records were available. Results of these analyses indicate that as the time frame over which the estimates were made increases, the overall errors associated with the estimates decreases with respect to loads computed using traditional USGS techniques. Using SSC data to compute loads tends to produce estimates closer to those computed by traditional techniques than those computed from TSS data. Loads computed from TSS data tend to be negatively biased with respect to those computed by traditional USGS techniques.

  5. Blood Pump Having a Magnetically Suspended Rotor

    NASA Technical Reports Server (NTRS)

    Antaki, James F. (Inventor); Paden, Bradley (Inventor); Burgreen, Gregory (Inventor); Groom, Nelson J. (Inventor)

    2001-01-01

    A blood pump preferably has a magnetically suspended rotor that rotates within a housing. The rotor may rotate about a stator disposed within the housing. Radial magnetic bearings may be defined within the stator and the rotor in order to suspend the rotor. The radial magnetic bearings may be passive magnetic bearings that include permanent magnets disposed within the stator and the rotor or active magnetic bearings. The pump may further include an axial magnetic bearing that may be either a passive or an active magnetic bearing. A motor that drives the rotor may be disposed within the housing in order to more easily dissipate heat generated by the motor. A primary flow path is defined between the rotor and the stator, and a secondary flow path is defined between the stator and the rotor. Preferably, a substantial majority of blood passes through the primary flow path. The secondary flow path is large enough so that it provides adequate flushing of the secondary flow path while being small enough to permit efficient operation of the radial magnet bearings across the secondary flow path.

  6. Blood Pump Having a Magnetically Suspended Rotor

    NASA Technical Reports Server (NTRS)

    Antaki, James F. (Inventor); Paden, Bradley (Inventor); Burgreen, Gregory (Inventor); Groom, Nelson J. (Inventor)

    2002-01-01

    A blood pump preferably has a magnetically suspended rotor that rotates within a housing. The rotor may rotate about a stator disposed within the housing. Radial magnetic bearings may be defined within the stator and the rotor in order to suspend the rotor. The radial magnetic bearings may be passive magnetic bearings that include permanent magnets disposed within the stator and the rotor or active magnetic bearings. The pump may further include an axial magnetic bearing that may be either a passive or an active magnetic bearing. A motor that drives the rotor may be disposed within the housing in order to more easily dissipate heat generated by the motor. A primary flow path is defined between the rotor and the stator, and a secondary flow path is defined between the stator and the rotor. Preferably, a substantial majority of blood passes through the primary flow path. The secondary flow path is large enough so that it provides adequate flushing of the secondary flow path while being small enough to permit efficient operation of the radial magnet bearings across the secondary flow path.

  7. Dynamics of suspended sediment in Lake Ontario

    NASA Technical Reports Server (NTRS)

    Pluhowski, E. J. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. The suspended sediment plumes generated by the Welland Canal and the Genesee River are identifiable in most band 5 frames received from ERTS-1. In descending order of value for plume detection in Lake Ontario are bands 4, 6, and 7. Little or no information content relative to plume detection is available in band 7. The Oswego River plume was not visible during low flow periods; however, it was identifiable immediately following storms. Increased suspended sediment loading emanating from storm runoff increases turbidity levels to the point where the plume becomes visible in the ERTS-1 imagery. Despite the fact that it is detectable from high altitude (60,000 feet) photography, the Niagara River plume was not visible in any of the ERTS-1 frames. Numerous examples of shoreline erosion were evident in the December 7, 1972, imagery of western Lake Ontario. Near shore lake circulation patterns are usually apparent whenever turbidity plumes are sensed by the satellite.

  8. Method for forming suspended micromechanical structures

    DOEpatents

    Fleming, James G.

    2000-01-01

    A micromachining method is disclosed for forming a suspended micromechanical structure from {111} crystalline silicon. The micromachining method is based on the use of anisotropic dry etching to define lateral features of the structure which are etched down into a {111}-silicon substrate to a first etch depth, thereby forming sidewalls of the structure. The sidewalls are then coated with a protection layer, and the substrate is dry etched to a second etch depth to define a spacing of the structure from the substrate. A selective anisotropic wet etchant (e.g. KOH, EDP, TMAH, NaOH or CsOH) is used to laterally undercut the structure between the first and second etch depths, thereby forming a substantially planar lower surface of the structure along a {111} crystal plane that is parallel to an upper surface of the structure. The lateral extent of undercutting by the wet etchant is controlled and effectively terminated by either timing the etching, by the location of angled {111}-silicon planes or by the locations of preformed etch-stops. This present method allows the formation of suspended micromechanical structures having large vertical dimensions and large masses while allowing for detailed lateral features which can be provided by dry etch definition. Additionally, the method of the present invention is compatible with the formation of electronic circuitry on the substrate.

  9. Fabrication and Characterization of Suspended Carbon Nanotube Devices in Liquid

    SciTech Connect

    Artyukhin, A; Stadermann, M; Stroeve, P; Bakajin, O; Noy, A

    2006-10-30

    Suspended carbon nanotube devices are a promising platform for future bio-electronic applications. Suspended carbon nanotube transistors have been previously fabricated in air; however all previous attempts to bring them into liquid failed. We analyze forces acting on the suspended nanotube devices during immersion into liquids and during device operation and show that surface tension forces acting on the suspended nanotubes during transfer into the liquid phase are responsible for the nanotube damage. We have developed a new strategy that circumvents these limitations by coating suspended nanotubes with a rigid inorganic shell in the gas phase. The coating reinforces the nanotubes and allows them to survive transfer through the interface. Subsequent removal of the coating in the solution phase restores pristine suspended nanotubes. We demonstrate that devices fabricated using this technique preserve their original electrical characteristics.

  10. Method for relating suspended-chemical concentrations to suspended-sediment particle-size classes in storm-water runoff

    USGS Publications Warehouse

    Rinella, Joseph F.; McKenzie, Stuart W.

    1982-01-01

    A method has been developed to relate suspended-chemical concentrations (associated with suspended sediments) in storm-water runoff to suspended-sediment particle-size classes. These classes are based on settling velocities in quiescent native water. This method requires processing 20 liters of water having a suspended-sediment concentration greater than 500 milligrams per liter. However, samples with suspended-sediment concentrations as low as 250 milligrams per liter may be analyzed, if sample volumes are increased to 50 liters. The time required for one person to separate suspended sediments into particle-size classes ranges from 6 to 14 hours. This report outlines procedures for processing metal, nutrient, and organic samples.

  11. Suspended sediment yield in Texas watersheds

    NASA Astrophysics Data System (ADS)

    Coonrod, Julia Ellen Allred

    The Texas Water Development Board collected suspended sediment samples across the state of Texas for approximately 60 years. Until this research, no comprehensive analysis of the data had been conducted. This study compiles the suspended sediment data along with corresponding streamflow and rainfall. GIS programs are developed which characterize watersheds corresponding to the sediment gauging stations. The watersheds are characterized according to topography, climate, soils, and land use. All of the data is combined to form several SAS data sets which can subsequently be analyzed using regression. Annual data for all of the stations across the state are classified temporally and spatially to determine trends in the sediment yield. In general, the suspended sediment load increases with increasing runoff but no correlation exists with rainfall. However, the annual average rainfall can be used to classify the watersheds according to climate, which improves the correlation between sediment load and runoff. The watersheds with no dams have higher sediment loads than watersheds with dams. Dams in the drier parts of Texas reduce the sediment load more than dams in the wetter part of the state. Sediment rating curves are developed separately for each basin in Texas. All but one of the curves fall into a band which varies by about two orders of magnitude. The study analyzes daily time series data for the Lavaca River near Edna station. USGS data are used to improve the sediment rating curve by the addition of physically related variables and interaction terms. The model can explain an additional 41% of the variability in sediment concentration compared to a simple bivariate regression of sediment load and flow. The TWDB daily data for the Lavaca River near Edna station are used to quantify temporal trends. There is a high correlation between sediment load and flowrate for the Lavaca River. The correlation can be improved by considering a flow-squared term and by

  12. Flywheel energy storage. II - Magnetically suspended superflywheel

    NASA Technical Reports Server (NTRS)

    Kirk, J. A.; Studer, P. A.

    1977-01-01

    This article, the second of a two part paper, describes the general design requirements for a flywheel energy storage system. A new superflywheel energy storage system, using a spokeless, magnetically suspended, composite material pierced disk rotor is proposed. The new system is configured around a permanent magnet ('flux biased') magnetic suspension system with active control in the radial direction and passive control in the axial direction. The storage ring is used as a moving rotor and electronic commutation of stationary armature coils is proposed. There is no mechanical contact with the rotating ring and long life and low run down losses are projected. A discussion of major components for a 10 kwh system is presented.

  13. Electron-Optics in suspended Graphene

    NASA Astrophysics Data System (ADS)

    Makk, Peter; Rickhaus, Peter; Zihlmann, Simon; Hess, Samuel; Weiss, Markus; Schoenenberger, Christian; Maurand, Romain; Tovari, Endre; Liu, Ming-Hao; Richter, Klaus

    We realized electron optical elements in ballistic graphene by utilizing local electrostatic gating. But in contrast to conventional optics, in graphene gapless p-n interfaces can be formed showing a negative index of refraction and the effect of Klein tunneling. The devices were fabricated using high-mobility suspended monolayer graphene on LOR resists. We demonstrate that with this technique a ballistic p-n junction can be formed and in magnetic fields striking features appear that can be traced to the formation of ``snake states'' along the p-n interface. We also show that electrons in ballistic graphene can be guided by gate potentials as photons in an optical fiber, and that Klein filtering increases the guiding efficiency. We showed that we can fill the electrostatic guiding channel mode by mode. Similarly, we have shown that tunable p-n interfaces can act as beam splitters.

  14. Improved algal harvesting using suspended air flotation.

    PubMed

    Wiley, Patrick E; Brenneman, Kristine J; Jacobson, Arne E

    2009-07-01

    Current methods to remove algae from a liquid medium are energy intensive and expensive. This study characterized algae contained within a wastewater oxidation pond and sought to identify a more efficient harvesting technique. Analysis of oxidation pond wastewater revealed that algae, consisting primarily of Chlorella and Scenedesmus, composed approximately 80% of the solids inventory during the study period. Results demonstrated that suspended air flotation (SAF) could harvest algae with a lower air:solids (A/S) ratio, lower energy requirements, and higher loading rates compared to dissolved air flotation (DAF) (P < 0.001). Identification of a more efficient algal harvesting system may benefit wastewater treatment plants by enabling cost effective means to reduce solids content of the final effluent. Furthermore, use of SAF to harvest commercially grown Chlorella and Scenedesmus may reduce manufacturing costs of algal-based products such as fuel, fertilizer, and fish food.

  15. Design consideration for magnetically suspended flywheel systems

    NASA Technical Reports Server (NTRS)

    Anand, D.; Kirk, J. A.; Frommer, D. A.

    1985-01-01

    Consideration is given to the design, fabrication, and testing of a magnetically suspended flywheel system for energy storage applications in space. The device is the prototype of a system combining passive suspension of the flywheel plate by samarium cobalt magnets and active control in the radial direction using eight separate magnetic coils. The bearing assembly was machined from a nickel-iron alloy, and the machine parts are all hydrogen annealed. Slots in the magnetic plate allow four independent quadrants for control. The motor/generator component of the system is a brushless dc-permanent magnetic/ironless engine using electronic communication. The system has been tested at over 2500 rpm with satisfactory results. The system characteristics of the flywheel for application in low earth orbit (LEO) are given in a table.

  16. Nanofluidic diode in a suspended nanoparticle crystal

    NASA Astrophysics Data System (ADS)

    Lei, Yinhua; Wang, Wei; Wu, Wengang; Li, Zhihong

    2010-06-01

    This work demonstrates a nanofluidic diode in a suspended nanoparticle crystal (S-NPC) constructed by sequentially packing hydroxyl-modified and amino-modified nanoparticles into a microfabricated silicon micropore. Current rectification in this nanofluidic diode comes from the asymmetric surface charge polarities along the nanochannel network inside the nanoparticle crystal. The maximum current rectification ratio was about 48 for the 173 nm S-NPC nanofluidic diode and the maximum forward current was larger than 700 nA at 3 V bias. Since it is inexpensive, easy to manufacture, and the surface charge properties are easily formed, having excellent electrical performance, this S-NPC nanofluidic diode holds application for biosensors.

  17. Shapes of a Suspended Curly Hair

    NASA Astrophysics Data System (ADS)

    Miller, J. T.; Lazarus, A.; Audoly, B.; Reis, P. M.

    2014-02-01

    We investigate how natural curvature affects the configuration of a thin elastic rod suspended under its own weight, as when a single strand of hair hangs under gravity. We combine precision desktop experiments, numerics, and theoretical analysis to explore the equilibrium shapes set by the coupled effects of elasticity, natural curvature, nonlinear geometry, and gravity. A phase diagram is constructed in terms of the control parameters of the system, namely the dimensionless curvature and weight, where we identify three distinct regions: planar curls, localized helices, and global helices. We analyze the stability of planar configurations, and describe the localization of helical patterns for long rods, near their free end. The observed shapes and their associated phase boundaries are then rationalized based on the underlying physical ingredients.

  18. Electrically rotating suspended films of polar liquids

    NASA Astrophysics Data System (ADS)

    Shirsavar, R.; Amjadi, A.; Tonddast-Navaei, A.; Ejtehadi, M. R.

    2011-02-01

    Controlled rotation of a suspended soap water film, simply generated by applying an electric field, has been reported recently. The film rotates when the applied electric field exceeds a certain threshold. In this study, we investigate the phenomenon in films made of a number of other liquids with various physical and chemical properties. Our measurements show that the intrinsic electrical dipole moments of the liquid molecules seems to be vital for the corresponding film rotation. All the investigated rotating liquids have a molecular electric dipole moment of above 1 Debye, while weakly polar liquids do not rotate. However, the liquids investigated here cover a wide range of physical parameters (e.g. viscosity, density, conductivity, etc.). So far, no significant correlation has been observed between the electric field thresholds and macroscopic properties of the liquids.

  19. 40 CFR 230.21 - Suspended particulates/turbidity.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Suspended particulates/turbidity. 230.21 Section 230.21 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING.../turbidity. (a) Suspended particulates in the aquatic ecosystem consist of fine-grained mineral...

  20. 40 CFR 230.21 - Suspended particulates/turbidity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... SECTION 404(b)(1) GUIDELINES FOR SPECIFICATION OF DISPOSAL SITES FOR DREDGED OR FILL MATERIAL Potential..., usually smaller than silt, and organic particles. Suspended particulates may enter water bodies as a..., and man's activities including dredging and filling. Particulates may remain suspended in the...

  1. 40 CFR 230.21 - Suspended particulates/turbidity.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... SECTION 404(b)(1) GUIDELINES FOR SPECIFICATION OF DISPOSAL SITES FOR DREDGED OR FILL MATERIAL Potential..., usually smaller than silt, and organic particles. Suspended particulates may enter water bodies as a..., and man's activities including dredging and filling. Particulates may remain suspended in the...

  2. Suspended particulate matter in the Chesapeake Bay entrance and adjacent shelf waters

    NASA Technical Reports Server (NTRS)

    Gingerich, K. J.; Oertel, G. F.

    1981-01-01

    Approximately 400 samples were collected from the mouth of the Chesapeake Bay for various analyses, including 138 for suspended solids. Characteristics of suspended solids that were analyzed included: total suspended matter; total suspended inorganics, total suspended organics; percent organics; particle size distribution; and presence or absence of 11 of the most prominent particle types.

  3. Contaminants in suspended sediment from the Fraser River basin

    SciTech Connect

    Sekela, M.; Baldazzi, C.; Moyle, G.; Brewer, R.

    1995-12-31

    The concentrations of trace organic contaminants were measured in suspended sediment samples collected upstream and downstream of six pulp mills located in the Fraser River basin. Sampling occurred at three hydrological periods; fall low flow, winter base flow (under ice) and spring freshet. Suspended sediments were analyzed for dioxins, furans, chlorinated phenolics and polycyclic aromatic hydrocarbons. Initial results indicate that (i) trace organic contaminants are detectable in suspended sediments collected over 265 river kilometers downstream of the nearest pulp mill; (ii) the 1992 to 1994 levels of 2,3,7,8-TCD-dioxin and 2,3,7,8-TCD-furan in Fraser river suspended sediments are lower than the levels measured in 1990; (iii) there is a measurable increase in trace organic contaminant levels in Fraser River suspended sediments associated with the initial rise in the Fraser River hydrograph at freshet.

  4. 2 CFR 180.715 - What notice does the suspending official give me if I am suspended?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 2 Grants and Agreements 1 2010-01-01 2010-01-01 false What notice does the suspending official give me if I am suspended? 180.715 Section 180.715 Grants and Agreements OFFICE OF MANAGEMENT AND BUDGET GOVERNMENTWIDE GUIDANCE FOR GRANTS AND AGREEMENTS Reserved OMB GUIDELINES TO AGENCIES...

  5. 21 CFR 1404.715 - What notice does the suspending official give me if I am suspended?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false What notice does the suspending official give me if I am suspended? 1404.715 Section 1404.715 Food and Drugs OFFICE OF NATIONAL DRUG CONTROL POLICY... this part, and any other Office of National Drug Control Policy procedures governing...

  6. Triad mode resonant interactions in suspended cables

    NASA Astrophysics Data System (ADS)

    Guo, TieDing; Kang, HouJun; Wang, LianHua; Zhao, YueYu

    2016-03-01

    A triad mode resonance, or three-wave resonance, is typical of dynamical systems with quadratic nonlinearities. Suspended cables are found to be rich in triad mode resonant dynamics. In this paper, modulation equations for cable's triad resonance are formulated by the multiple scale method. Dynamic conservative quantities, i.e., mode energy and Manley-Rowe relations, are then constructed. Equilibrium/dynamic solutions of the modulation equations are obtained, and full investigations into their stability and bifurcation characteristics are presented. Various bifurcation behaviors are detected in cable's triad resonant responses, such as saddle-node, Hopf, pitchfork and period-doubling bifurcations. Nonlinear behaviors, like jump and saturation phenomena, are also found in cable's responses. Based upon the bifurcation analysis, two interesting properties associated with activation of cable's triad resonance are also proposed, i.e., energy barrier and directional dependence. The first gives the critical amplitude of high-frequency mode to activate cable's triad resonance, and the second characterizes the degree of difficulty for activating cable's triad resonance in two opposite directions, i.e., with positive or negative internal detuning parameter.

  7. Acoustoelectric Current in Suspended Quantum Point Contacts

    NASA Astrophysics Data System (ADS)

    Kreft, Dustin J.

    Here, I present a detailed analysis and discussion of acoustoelectric current and the behavior of said current under the influence of a magnetic field and its interactions with quantum point contacts (QPCs). The QPCs lie on a suspended nano-bridge, which acts as an acoustic waveguide, allowing a stronger electron-phonon coupling; and hence, a larger acoustoelectric current with amplified conductance effects at a high temperature of 4.2 K. The acoustoelectric current is first studied under the influence of a perpendicular magnetic field. Through this measurement a theoretical model was developed to accurately describe and reproduce the measurement trend; showing how the acoustoelectric current is strongly dependent on the surface acoustic wave (SAW) attenuation and the two dimensional electron gas (2DEG) conductance changes under such conditions. The next set of measurements focus on the acoustoelectric current and its interactions with the potential created by applying a negative bias to the QPCs. Here, the electronically confined region gives rise to enhanced electron-phonon interactions which manifest themselves as a change in acoustoelectric current polarity, due to phonon back scattering, and enhanced oscillations in the measured current due to subband depopulation and the change in the potential landscape. Further information is provided such as fabrication steps, theoretical background on QPCs and SAWs, additional information of SAW-QPC interactions under the influence of a magnetic field, and phase locked acoustoelectric current with QPC pinch off.

  8. Evaporation-Driven Bioassays in Suspended Droplets.

    PubMed

    Hernandez-Perez, Ruth; Fan, Z Hugh; Garcia-Cordero, Jose L

    2016-07-19

    The microtiter plate has been an essential tool for diagnostics, high-throughput screening, and biological assays. We present an alternative platform to perform bioassays in a microplate format that exploits evaporation to drive assay reactions. Our method consists of droplets suspended on plastic pillars; reactions occur in these droplets instead of the wells. The pillars are fabricated by milling, and the rough surface created by this fabrication method pins the droplet to a constant contact line during the assay and also acts as a hydrophobic surface. Upon evaporation, natural convection arising from Marangoni currents mixes solutions in the droplet, which speeds up assay reactions, decreases assay times, and increases limits of detection. As a proof of concept we implemented two colorimetric assays to detect glucose and proteins in only 1.5 μL, without any external devices for mixing and with a digital microscope as a readout mechanism. Our platform is an ideal alternative to the microtiter plate, works with different volumes, is compatible with commercially available reagent dispensers and plate-readers, and could have broad applications in diagnostics and high-throughput screening. PMID:27331825

  9. Droplet Suspended on a Wire Begins Ignition

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The Fiber Supported Droplet Combustion Experiment completing a number of successful burns on STS-94, July 11, 1997, MET:9/17:40 (approximate). The photo shows a droplet of 95% heptane and 5% hexadecane, suspended and positioned by the fiber wire, just as it is being ignited by the glowing coil beneath. Study of the physical properties of burning fuel from this experiment is expected to contribute to more efficient use of fossil fuels and reduction of combustion by-products on Earth. The sequence is from a time-lapse movie (34 seconds condensed to 12 seconds), and clearly shows particles emanating from the droplet during the burn. The droplet shrank to nothing as it was consumed. FSDC-2 studied fundamental phenomena related to liquid fuel droplet combustion in air. Pure fuels and mixtures of fuels were burned as isolated single and dual droplets with and without forced air convection. The FSDC guest investigator was Forman Williams, University of California, San Diego. The experiment was part of the space research investigations conducted during the Microgravity Science Laboratory-1R mission (STS-94, July 1-17 1997). Advanced combustion experiments will be a part of investigations plarned for the International Space Station. (1.2 MB, 11-second MPEG, screen 320 x 240 pixels; downlinked video, higher quality not available) A still JPG composite of this movie is available at http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-0300180.html.

  10. 77 FR 44233 - Clothianidin; Emergency Petition To Suspend; Notice of Availability

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-27

    ... AGENCY Clothianidin; Emergency Petition To Suspend; Notice of Availability AGENCY: Environmental... immediately suspend Clothianidin and take other actions affecting the registration. The EPA is announcing the... organizations requesting that the EPA suspend registrations for the insecticide clothianidin for the...

  11. Methods of and system for swing damping movement of suspended objects

    DOEpatents

    Jones, J.F.; Petterson, B.J.; Strip, D.R.

    1991-03-05

    A payload suspended from a gantry is swing damped in accordance with a control algorithm based on the periodic motion of the suspended mass or by servoing on the forces induced by the suspended mass. 13 figures.

  12. Comparability of suspended-sediment concentration and total suspended solids data

    USGS Publications Warehouse

    Gray, John R.; Glysson, G.D.; Turcios, L.M.; Schwarz, G.E.

    2000-01-01

    Two laboratory analytical methods ? suspended-sediment concentration (SSC) and total suspended solids (TSS) ? are predominantly used to quantify concentrations of suspended solid-phase material in surface waters of the United States. The analytical methods differ. SSC data are produced by measuring the dry weight of all the sediment from a known volume of a water-sediment mixture. TSS data are produced by several methods, most of which entail measuring the dry weight of sediment from a known volume of a subsample of the original. An evaluation of 3,235 paired SSC and TSS data, of which 860 SSC values include percentages of sand-size material, shows bias in the relation between SSC and TSS ?SSC values tend to increase at a greater rate than their corresponding paired TSS values. As sand-size material in samples exceeds about a quarter of the sediment dry weight, SSC values tend to exceed their corresponding paired TSS values. TSS analyses of three sets of quality-control samples (35 samples) showed unexpectedly small sediment recoveries and relatively large variances in the TSS data. Two quality-control data sets (18 samples) that were analyzed for SSC showed both slightly deficient sediment recoveries, and variances that are characteristic of most other quality-control data compiled as part of the U.S. Geological Survey?s National Sediment Laboratory Quality Assurance Program. The method for determining TSS, which was originally designed for analyses of wastewater samples, is shown to be fundamentally unreliable for the analysis of natural-water samples. In contrast, the method for determining SSC produces relatively reliable results for samples of natural water, regardless of the amount or percentage of sand-size material in the samples. SSC and TSS data collected from natural water are not comparable and should not be used interchangeably. The accuracy and comparability of suspended solid-phase concentrations of the Nation?s natural waters would be greatly

  13. Distribution and concentration of suspended matter in Delaware Bay

    NASA Technical Reports Server (NTRS)

    Klemas, V. (Principal Investigator); Philpot, W.

    1977-01-01

    The author has identified the following significant results. The problem of remote sensing of suspended matter in water was analyzed in terms of the single-scattering albedo, and a semiempirical relationship between satellite radiance measurements and the concentration of suspended matter in the water was developed. The relationship was tested using data from the 7 July 1973 LANDSAT overpass of Delaware Bay with good results. Suspended sediment concentration maps for the entire Delaware Bay were prepared using radiance values extracted from LANDSAT MSS imagery and correlating them with ground truth samples collected from boats and helicopter.

  14. Multifunctional flexible free-standing titanate nanobelt membranes as efficient sorbents for the removal of radioactive 90Sr2+ and 137Cs+ ions and oils

    NASA Astrophysics Data System (ADS)

    Wen, Tao; Zhao, Zhiwei; Shen, Congcong; Li, Jiaxing; Tan, Xiaoli; Zeb, Akif; Wang, Xiangke; Xu, An-Wu

    2016-02-01

    For the increasing attention focused on saving endangered environments, there is a growing need for developing membrane materials able to perform complex functions such as removing radioactive pollutants and oil spills from water. A major challenge is the scalable fabrication of membranes with good mechanical and thermal stability, superior resistance to radiation, and excellent recyclability. In this study, we constructed a multifunctional flexible free-standing sodium titanate nanobelt (Na-TNB) membrane that was assembled as advanced radiation-tainted water treatment and oil uptake. We compared the adsorption behavior of 137Cs+ and 90Sr2+ on Na-TNB membranes under various environmental conditions. The maximum adsorption coefficient value (Kd) for Sr2+ reaches 107 mL g-1. The structural collapse of the exchange materials were confirmed by XRD, FTIR and XPS spectroscopy as well as Raman analysis. The adsorption mechanism of Na-TNB membrane is clarified by forming a stable solid with the radioactive cations permanently trapped inside. Besides, the engineered multilayer membrane is exceptionally capable in selectively and rapidly adsorbing oils up to 23 times the adsorbent weight when coated with a thin layer of hydrophobic molecules. This multifunctional membrane has exceptional potential as a suitable material for next generation water treatment and separation technologies.

  15. Size and Temperature Dependence of Electron Transfer between CdSe Quantum Dots and a TiO 2 Nanobelt

    SciTech Connect

    Tafen, De Nyago; Prezhdo, Oleg V.

    2015-02-24

    Understanding charge transfer reactions between quantum dots (QD) and metal oxides is fundamental for improving photocatalytic, photovoltaic and electronic devices. The complexity of these processes makes it difficult to find an optimum QD size with rapid charge injection and low recombination. We combine time-domain density functional theory with nonadiabatic molecular dynamics to investigate the size and temperature dependence of the experimentally studied electron transfer and charge recombination at CdSe QD-TiO2 nanobelt (NB) interfaces. The electron injection rate shows strong dependence on the QD size, increasing for small QDs. The rate exhibits Arrhenius temperature dependence, with the activation energy of the order of millielectronvolts. The charge recombination process occurs due to coupling of the electronic subsystem to vibrational modes of the TiO2 NB. Inelastic electron-phonon scattering happens on a picosecond time scale, with strong dependence on the QD size. Our simulations demonstrate that the electron-hole recombination rate decreases significantly as the QD size increases, in excellent agreement with experiments. The temperature dependence of the charge recombination rates can be successfully modeled within the framework of the Marcus theory through optimization of the electronic coupling and the reorganization energy. Our simulations indicate that by varying the QD size, one can modulate the photoinduced charge separation and charge recombination, fundamental aspects of the design principles for high efficiency devices.

  16. Multifunctional flexible free-standing titanate nanobelt membranes as efficient sorbents for the removal of radioactive 90Sr2+ and 137Cs+ ions and oils

    PubMed Central

    Wen, Tao; Zhao, Zhiwei; Shen, Congcong; Li, Jiaxing; Tan, Xiaoli; Zeb, Akif; Wang, Xiangke; Xu, An-Wu

    2016-01-01

    For the increasing attention focused on saving endangered environments, there is a growing need for developing membrane materials able to perform complex functions such as removing radioactive pollutants and oil spills from water. A major challenge is the scalable fabrication of membranes with good mechanical and thermal stability, superior resistance to radiation, and excellent recyclability. In this study, we constructed a multifunctional flexible free-standing sodium titanate nanobelt (Na-TNB) membrane that was assembled as advanced radiation-tainted water treatment and oil uptake. We compared the adsorption behavior of 137Cs+ and 90Sr2+ on Na-TNB membranes under various environmental conditions. The maximum adsorption coefficient value (Kd) for Sr2+ reaches 107 mL g−1. The structural collapse of the exchange materials were confirmed by XRD, FTIR and XPS spectroscopy as well as Raman analysis. The adsorption mechanism of Na-TNB membrane is clarified by forming a stable solid with the radioactive cations permanently trapped inside. Besides, the engineered multilayer membrane is exceptionally capable in selectively and rapidly adsorbing oils up to 23 times the adsorbent weight when coated with a thin layer of hydrophobic molecules. This multifunctional membrane has exceptional potential as a suitable material for next generation water treatment and separation technologies. PMID:26865116

  17. Multifunctional flexible free-standing titanate nanobelt membranes as efficient sorbents for the removal of radioactive (90)Sr(2+) and (137)Cs(+) ions and oils.

    PubMed

    Wen, Tao; Zhao, Zhiwei; Shen, Congcong; Li, Jiaxing; Tan, Xiaoli; Zeb, Akif; Wang, Xiangke; Xu, An-Wu

    2016-01-01

    For the increasing attention focused on saving endangered environments, there is a growing need for developing membrane materials able to perform complex functions such as removing radioactive pollutants and oil spills from water. A major challenge is the scalable fabrication of membranes with good mechanical and thermal stability, superior resistance to radiation, and excellent recyclability. In this study, we constructed a multifunctional flexible free-standing sodium titanate nanobelt (Na-TNB) membrane that was assembled as advanced radiation-tainted water treatment and oil uptake. We compared the adsorption behavior of (137)Cs(+) and (90)Sr(2+) on Na-TNB membranes under various environmental conditions. The maximum adsorption coefficient value (Kd) for Sr(2+) reaches 10(7) mL g(-1). The structural collapse of the exchange materials were confirmed by XRD, FTIR and XPS spectroscopy as well as Raman analysis. The adsorption mechanism of Na-TNB membrane is clarified by forming a stable solid with the radioactive cations permanently trapped inside. Besides, the engineered multilayer membrane is exceptionally capable in selectively and rapidly adsorbing oils up to 23 times the adsorbent weight when coated with a thin layer of hydrophobic molecules. This multifunctional membrane has exceptional potential as a suitable material for next generation water treatment and separation technologies. PMID:26865116

  18. Ultrahigh Capacity Due to Multi-Electron Conversion Reaction in Reduced Graphene Oxide-Wrapped MoO2 Porous Nanobelts.

    PubMed

    Tang, Wei; Peng, Cheng Xin; Nai, Chang Tai; Su, Jie; Liu, Yan Peng; Reddy, M V Venkatashamy; Lin, Ming; Loh, Kian Ping

    2015-05-01

    Multivalent transition metal oxides (MOx ) containing redox centers which can theoretically accept more than one electron have been suggested as promising anode materials for high-performance lithium ion batteries (LIBs). The Li-storage mechanism of these oxides is suggested to involve an unusual conversion reaction leading to the formation of metallic nanograins and Li2 O; however, a full-scale conversion reaction is seldom observed in molybdenum dioxide (MoO2 ) at room temperature due to slow kinetics. Herein, a full-scale multi-electron conversion reaction, leading to a high reversible capacity (974 mA h g(-1) charging capacity at 60 mA g(-1) ) in LIBs, is realized in a hybrid consisting of reduced graphene oxide (rGO) sheet-wrapped MoO2 porous nanobelts (rGO/MoO2 NBs). The rGO wrapping layers stabilize the nanophase transition in MoO2 and alleviate volume swing effects during lithiation/delithiation processes. This enables the hybrid to exhibit great cycle stability (tested to around 1900 cycles) and ultrafast rate capability (tested up to 50 A g(-1) ). PMID:25620728

  19. In situ synthesis of Ni(OH)2 nanobelt modified electroactive poly(vinylidene fluoride) thin films: remarkable improvement in dielectric properties.

    PubMed

    Thakur, Pradip; Kool, Arpan; Bagchi, Biswajoy; Hoque, Nur Amin; Das, Sukhen; Nandy, Papiya

    2015-05-21

    A facile and low cost synthesis of Ni(OH)2 nanobelt (NB) modified electroactive poly(vinylidene fluoride) (PVDF) thin films with excellent dielectric properties has been reported via in situ formation of Ni(OH)2 NBs in the PVDF matrix. The formation and morphology of the NBs are confirmed by UV-visible spectroscopy and field emission scanning electron microscopy respectively. A remarkable improvement in electroactive β phase nucleation (∼82%) and the dielectric constant (ε ∼ 3.1 × 10(6) at 20 Hz) has been observed in the nanocomposites (NCs). The interface between the NBs and the polymer matrix plays a crucial role in the enhancement of the electroactive β phase and the dielectric properties of thin films. Strong interaction via hydrogen bonds between Ni(OH)2 NBs and the PVDF matrix is the main reason for enhancement in β phase crystallization and improved dielectric properties. The NC thin films can be utilized for potential applications as high energy storage devices like supercapacitors, solid electrolyte batteries, self-charging power cells, piezoelectric nanogenerators, and thin film transistors and sensors. PMID:25915166

  20. Introduction to suspended-sediment sampling

    USGS Publications Warehouse

    Nolan, K. Michael; Gray, John R.; Glysson, G. Douglas

    2005-01-01

    Knowledge of the amount and timing of sediment transport in streams is important to those directly or indirectly responsible for developing and managing water and land resources. Such data are often used to judge the health of watershed and the success or failure of activities designed to mitigate adverse impacts of sediment on streams and stream habitats. This training class presents an introduction to methods currently used by the U.S. Geological Survey (USGS) to sample suspended-sediment concentrations in streams. The presentation is narrated, but you control the pace of the presentation. If the computer you are using can view 'MPEG' videos you will be able to take advantage of videos interspersed in the presentation. A test, found at the end of the presentation, can be taken to assess how well you understood the training material. The class, which is registered as class SW4416 with the National Training Center of the USGS, should take two or three hours to complete. In order to use the presentation provided via this Web page, you will need to download a large disc images (linked below) and 'burn' it to a blank CD-ROM using a CD-ROM recorder on your computer. The presentation will only run on a Windows-based personal computer (PC). The presentation was developed using Macromedia Director MX 20041 and is contained in the file 'SIR05-5077.exe' which should autolaunch. If it does not, the presentation can be started by double-clicking on the file name. A sound card and speakers are necessary to take advantage of narrations that accompany the presentation. Text of narrations is provided, if you are unable to listen to narrations. Instructions for installing and running the presentation are included in the file 'Tutorial.htm', which is on the CD. 1 Registered Trademark: Macromedia Incorporated

  1. Ratios of total suspended solids to suspended sediment concentrations by particle size

    USGS Publications Warehouse

    Selbig, W.R.; Bannerman, R.T.

    2011-01-01

    Wet-sieving sand-sized particles from a whole storm-water sample before splitting the sample into laboratory-prepared containers can reduce bias and improve the precision of suspended-sediment concentrations (SSC). Wet-sieving, however, may alter concentrations of total suspended solids (TSS) because the analytical method used to determine TSS may not have included the sediment retained on the sieves. Measuring TSS is still commonly used by environmental managers as a regulatory metric for solids in storm water. For this reason, a new method of correlating concentrations of TSS and SSC by particle size was used to develop a series of correction factors for SSC as a means to estimate TSS. In general, differences between TSS and SSC increased with greater particle size and higher sand content. Median correction factors to SSC ranged from 0.29 for particles larger than 500m to 0.85 for particles measuring from 32 to 63m. Great variability was observed in each fraction-a result of varying amounts of organic matter in the samples. Wide variability in organic content could reduce the transferability of the correction factors. ?? 2011 American Society of Civil Engineers.

  2. Estimation of suspended-sediment rating curves and mean suspended-sediment loads

    USGS Publications Warehouse

    Crawford, Charles G.

    1991-01-01

    A simulation study was done to evaluate: (1) the accuracy and precision of parameter estimates for the bias-corrected, transformed-linear and non-linear models obtained by the method of least squares; (2) the accuracy of mean suspended-sediment loads calculated by the flow-duration, rating-curve method using model parameters obtained by the alternative methods. Parameter estimates obtained by least squares for the bias-corrected, transformed-linear model were considerably more precise than those obtained for the non-linear or weighted non-linear model. The accuracy of parameter estimates obtained for the biascorrected, transformed-linear and weighted non-linear model was similar and was much greater than the accuracy obtained by non-linear least squares. The improved parameter estimates obtained by the biascorrected, transformed-linear or weighted non-linear model yield estimates of mean suspended-sediment load calculated by the flow-duration, rating-curve method that are more accurate and precise than those obtained for the non-linear model.

  3. Raman spectroscopy of ripple formation in suspended graphene.

    PubMed

    Chen, Chun-Chung; Bao, Wenzhong; Theiss, Jesse; Dames, Chris; Lau, Chun Ning; Cronin, Stephen B

    2009-12-01

    Using Raman spectroscopy, we measure the optical phonon energies of suspended graphene before, during, and after thermal cycling between 300 and 700 K. After cycling, we observe large upshifts ( approximately 25 cm(-1)) of the G band frequency in the graphene on the substrate region due to compression induced by the thermal contraction of the underlying substrate, while the G band in the suspended region remains unchanged. From these large upshifts, we estimate the compression in the substrate region to be approximately 0.4%. The large mismatch in compression between the substrate and suspended regions causes a rippling of the suspended graphene, which compensates for the change in lattice constant due to the compression. The amplitude (A) and wavelength (lambda) of the ripples, as measured by atomic force microscopy, correspond to an effective change in length Deltal/l that is consistent with the compression values determined from the Raman data. PMID:19807131

  4. 10 CFR 15.53 - Reasons for suspending collection action.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., with due regard to the 10-year limitation for administrative offset prescribed by 31 U.S.C. 3716(e)(1... principal of the debt with interest at a later date. (e)(1) The NRC shall suspend collection activity...

  5. Detail of window treatment, suspended radiators, and fluorescent lights, prop ...

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

    Detail of window treatment, suspended radiators, and fluorescent lights, prop shop. View to east. - San Bernardino Valley College, Auditorium, 701 South Mount Vernon Avenue, San Bernardino, San Bernardino County, CA

  6. 38. INTERIOR VIEW OF TANK. Suspended wooden platform obscures bottom ...

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

    38. INTERIOR VIEW OF TANK. Suspended wooden platform obscures bottom of tank No date - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

  7. Suspended sediment apportionment in a South-Korean mountain catchment

    NASA Astrophysics Data System (ADS)

    Birkholz, Axel; Meusburger, Katrin; Park, Ji-Hyung; Alewell, Christine

    2016-04-01

    Due to the rapid agricultural expansion and intensification during the last decades in South-Korea, large areas of hill slope forests were transformed to paddies and vegetable fields. The intensive agriculture and the easily erodible soils in our catchment are a major reason for the increased erosion causing suspended sediments to infiltrate into the close drinking water reservoir. The drinking water reservoir Lake Soyang provides water supply for over ten million people in Seoul. Landscape managers need to know the exact origin of these sediments before they can create landscape amelioration schemes. We applied a compound-specific stable isotope (CSSI) approach (Alewell et al., 2015) to apportion the sources of the suspended sediments between forest and agricultural soil contribution to the suspended sediments in a different catchment and applied the same approach to identify and quantify the different sources of the suspended sediments in the river(s) contributing to Lake Soyang. We sampled eight soil sites within the catchment considering the different landuse types forest, rice paddies, maize and vegetables. Suspended sediments were sampled at three outlets of the different sub-catchments. Soils and suspended sediments are analysed for bulk carbon and nitrogen isotopes, compound-specific carbon isotopes of plant-wax derived long-chain fatty acids and long-chain n-alkanes. Fatty acid and alkane isotopes are then used in mixing calculations and the mixing model software IsoSource to find out the contribution of the different source soils to the suspended sediments. We present first data of the source soils and the suspended sediments. C. Alewell, A. Birkholz, K. Meusburger, Y. Schindler-Wildhaber, L. Mabit, 2015. Sediment source attribution from multiple land use systems with CSIA. Biogeosciences Discuss. 12: 14245-14269.

  8. Comparability of suspended-sediment concentration and total suspended-solids data for two sites on the L'Anguille River, Arkansas, 2001 to 2003

    USGS Publications Warehouse

    Galloway, Joel M.; Evans, Dennis A.; Green, W. Reed

    2005-01-01

    Suspended-sediment concentration and total suspended solids data collected with automatic pumping samplers at the L'Anguille River near Colt and the L'Anguille River at Palestine, Arkansas, August 2001 to October 2003 were compared using ordinary least squares regression analyses to determine the relation between the two datasets for each of the two sites. The purpose of this report is to describe the suspended-sediment concentration and total suspended-solids data and examine the comparability of the two datasets for each site. Suspended-sediment concentration and total suspended solids data for the L'Anguille River varied spatially and temporally from August 2001 to October 2003. The site at the L'Anguille River at Palestine represents a larger portion of the L'Anguille River Basin than the site near Colt, and generally had higher median suspended-sediment concentration and total suspended solids and greater ranges in values. The differences between suspended-sediment concentration and total suspended solids data for the L'Anguille River near Colt appeared inversely related to streamflow and not related to time. The relation between suspended-sediment concentration and total suspended solids at the L'Anguille River at Palestine was more variable than at Colt and did not appear to have a relation with flow or time. The relation between suspended-sediment concentration and total suspended solids for the L'Anguille River near Colt shows that total suspended solids increased proportionally as suspended-sediment concentration increased. However, the relation between suspended-sediment concentration and total suspended solids for the L'Anguille River at Palestine showed total suspended solids increased less proportionally as suspended-sediment concentration increased compared to the L'Anguille River near Colt. Differences between the two analytical methods may partially explain differences between the suspended-sediment concentration and total suspended solids data at

  9. 33 CFR 159.126a - Suspended solids test: Type II devices.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... suspended solids in accordance with 40 CFR part 136. The arithmetic mean of the total suspended solids in 38... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Suspended solids test: Type II... Suspended solids test: Type II devices. During the sewage processing test (§ 159.121) 40 effluent...

  10. 33 CFR 159.126a - Suspended solids test: Type II devices.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... suspended solids in accordance with 40 CFR Part 136. The arithmetic mean of the total suspended solids in 38... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Suspended solids test: Type II... Suspended solids test: Type II devices. During the sewage processing test (§ 159.121) 40 effluent...

  11. 33 CFR 159.126a - Suspended solids test: Type II devices.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... suspended solids in accordance with 40 CFR Part 136. The arithmetic mean of the total suspended solids in 38... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Suspended solids test: Type II... Suspended solids test: Type II devices. During the sewage processing test (§ 159.121) 40 effluent...

  12. 33 CFR 159.126a - Suspended solids test: Type II devices.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... suspended solids in accordance with 40 CFR Part 136. The arithmetic mean of the total suspended solids in 38... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Suspended solids test: Type II... Suspended solids test: Type II devices. During the sewage processing test (§ 159.121) 40 effluent...

  13. 33 CFR 159.126a - Suspended solids test: Type II devices.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... suspended solids in accordance with 40 CFR Part 136. The arithmetic mean of the total suspended solids in 38... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Suspended solids test: Type II... Suspended solids test: Type II devices. During the sewage processing test (§ 159.121) 40 effluent...

  14. On Suspended matter grain size in Baltic sea

    NASA Astrophysics Data System (ADS)

    Bubnova, Ekaterina; Sivkov, Vadim; Zubarevich, Victor

    2016-04-01

    Suspended matter grain size data were gathered during the 25th research vessel "Akademik Mstislav Keldysh" cruise (1991, September-October). Initial quantitative data were obtained with a use of the Coulter counter and subsequently modified into volume concentrations (mm3/l) for size intervals. More than 80 samples from 15 stations were analyzed (depth range 0-355 m). The main goal of research was to illustrate the spatial variability of suspended matter concentration and dispersion in Baltic Sea. The mutual feature of suspended matter grain size distribution is the logical rise of particle number along with descending of particle's size. Vertical variability of grain size distribution was defined by Baltic Sea hydrological structure, including upper mixed layer - from the surface to the thermocline - with 35 m thick, cold intermediate layer - from the thermocline to the halocline- and bottom layer, which lied under the halocline. Upper layer showed a rise in total suspended matter concentration (up to 0.6 mm3/l), while cold intermediate level consisted of far more clear water (up to 0.1 mm3/l). Such a difference is caused by the thermocline boarding role. Meanwhile, deep bottom water experienced surges in suspended matter concentration owing to the nepheloid layer presence and "liquid bottom" effect. Coastal waters appeared to have the highest amount of particles (up to 5.0 mm3/l). Suspended matter grain size distribution in the upper mixed layer revealed a peak of concentration at 7 μ, which can be due to autumn plankton bloom. Another feature in suspended matter grain size distribution appeared at the deep layer below halocline, where both O2 and H2S were observed and red/ox barrier is. The simultaneous presence of Fe and Mn (in solutions below red/ox barrier) and O2 leads to precipitation of oxyhydrates Fe and Mn and grain size distribution graph peaking at 4.5 μ.

  15. Suspended sediment transport under estuarine tidal channel conditions

    USGS Publications Warehouse

    Sternberg, R.W.; Kranck, K.; Cacchione, D.A.; Drake, D.E.

    1988-01-01

    A modified version of the GEOPROBE tripod has been used to monitor flow conditions and suspended sediment distribution in the bottom boundary layer of a tidal channel within San Francisco Bay, California. Measurements were made every 15 minutes over three successive tidal cycles. They included mean velocity profiles from four electromagnetic current meters within 1 m of the seabed; mean suspended sediment concentration profiles from seven miniature nephelometers operated within 1 m of the seabed; near-bottom pressure fluctuations; vertical temperature gradient; and bottom photographs. Additionally, suspended sediment was sampled from four levels within 1 m of the seabed three times during each successive flood and ebb cycle. While the instrument was deployed, STD-nephelometer measurements were made throughout the water column, water samples were collected each 1-2 hours, and bottom sediment was sampled at the deployment site. From these measurements, estimates were made of particle settling velocity (ws) from size distributions of the suspended sediment, friction velocity (U*) from the velocity profiles, and reference concentration (Ca) was measured at z = 20 cm. These parameters were used in the suspended sediment distribution equations to evaluate their ability to predict the observed suspended sediment profiles. Three suspended sediment particle conditions were evaluated: (1) individual particle size in the 4-11 ?? (62.5-0.5 ??m) range with the reference concentration Ca at z = 20 cm (C??), (2) individual particle size in the 4-6 ?? size range, flocs representing the 7-11 ?? size range with the reference concentration Ca at z = 20 cm (Cf), and (3) individual particle size in the 4-6 ?? size range, flocs representing the 7-11 ?? size range with the reference concentration predicted as a function of the bed sediment size distribution and the square of the excess shear stress. In addition, computations of particle flux were made in order to show vertical variations

  16. Three Human Cell Types Respond to Multi-Walled Carbon Nanotubes and Titanium Dioxide Nanobelts with Cell-Specific Transcriptomic and Proteomic Expression Patterns.

    SciTech Connect

    Tilton, Susan C.; Karin, Norman J.; Tolic, Ana; Xie, Yumei; Lai, Xianyin; Hamilton, Raymond F.; Waters, Katrina M.; Holian, Andrij; Witzmann, Frank A.; Orr, Galya

    2014-08-01

    The growing use of engineered nanoparticles (NPs) in commercial and medical applications raises the urgent need for tools that can predict NP toxicity. Global transcriptome and proteome analyses were conducted on three human cell types, exposed to two high aspect ratio NP types, to identify patterns of expression that might indicate high versus low NP toxicity. Three cell types representing the most common routes of human exposure to NPs, including macrophage-like (THP-1), small airway epithelial and intestinal (Caco-2/HT29-MTX) cells, were exposed to TiO2 nanobelts (TiO2-NB; high toxicity) and multi-walled carbon nanotubes (MWCNT; low toxicity) at low (10 µg/mL) and high (100 µg/mL) concentrations for 1 and 24 h. Unique patterns of gene and protein expressions were identified for each cell type, with no differentially expressed (p < 0.05, 1.5-fold change) genes or proteins overlapping across all three cell types. While unique to each cell type, the early response was primarily independent of NP type, showing similar expression patterns in response to both TiO2-NB and MWCNT. The early response might, therefore, indicate a general response to insult. In contrast, the 24 h response was unique to each NP type. The most significantly (p < 0.05) enriched biological processes in THP-1 cells indicated TiO2-NB regulation of pathways associated with inflammation, apoptosis, cell cycle arrest, DNA replication stress and genomic instability, while MWCNT-regulated pathways indicated increased cell proliferation, DNA repair and anti-apoptosis. These two distinct sets of biological pathways might, therefore, underlie cellular responses to high and low NP toxicity, respectively.

  17. Highly selective and sensitive response of 30.5 % of sprayed molybdenum trioxide (MoO3) nanobelts for nitrogen dioxide (NO2) gas detection.

    PubMed

    Mane, A A; Suryawanshi, M P; Kim, J H; Moholkar, A V

    2016-12-01

    The molybdenum trioxide (MoO3) thin films have been successfully deposited onto the glass substrates using chemical spray pyrolysis (CSP) deposition technique at various substrate temperatures ranging from 300°C to 450°C with an interval of 50°C. The effect of substrate temperature on the structural, morphological, optical and gas sensing properties of MoO3 thin films has been thoroughly investigated. X-ray diffraction analysis reveals that all the films have an orthorhombic crystal structure and are polycrystalline in nature. FE-SEM micrographs depict the formation of nanobelts-like morphology. AFM study reveals that the RMS surface roughness of MoO3 thin films increases from 8.6nm to 12nm with increase in substrate temperature from 300°C to 400°C and then decreases to 11.5nm for substrate temperature of 450°C. Optical results show that the band gap of MoO3 thin films decreases from 3.92eV to 3.44eV. The selectivity studies show that the gas response of various gases varies as NH3

  18. Attached and suspended microbial communities in a pristine confined aquifer

    NASA Astrophysics Data System (ADS)

    Flynn, Theodore M.; Sanford, Robert A.; Bethke, Craig M.

    2008-07-01

    We compare the community of microbes attached to the sediments in a pristine confined aquifer to the free-floating community suspended in the groundwater there. We sampled the attached microbial community at 19 wells completed in the glacial Mahomet aquifer in east central Illinois using in situ samplers, and we sampled the suspended community by filtering microbes from groundwater. At each well, we profiled the two communities using terminal restriction fragment length polymorphism and compared the profiles we obtained with multivariate statistical analyses. Some populations at a well are detected both in the attached and suspended communities, but the shared populations represent, on average, only one third of each community; the remaining populations are detected exclusively in one community or the other. Clones closely related to the iron-reducing bacteria Geobacter and Geothrix represent more than 20% of the total attached community detected at many wells, but at no well do they make up more than 1% of the suspended community. To fully characterize the microbial community in an aquifer, it may be necessary to sample the attached as well as suspended communities.

  19. Electron-beam induced nano-etching of suspended graphene

    PubMed Central

    Sommer, Benedikt; Sonntag, Jens; Ganczarczyk, Arkadius; Braam, Daniel; Prinz, Günther; Lorke, Axel; Geller, Martin

    2015-01-01

    Besides its interesting physical properties, graphene as a two-dimensional lattice of carbon atoms promises to realize devices with exceptional electronic properties, where freely suspended graphene without contact to any substrate is the ultimate, truly two-dimensional system. The practical realization of nano-devices from suspended graphene, however, relies heavily on finding a structuring method which is minimally invasive. Here, we report on the first electron beam-induced nano-etching of suspended graphene and demonstrate high-resolution etching down to ~7 nm for line-cuts into the monolayer graphene. We investigate the structural quality of the etched graphene layer using two-dimensional (2D) Raman maps and demonstrate its high electronic quality in a nano-device: A 25 nm-wide suspended graphene nanoribbon (GNR) that shows a transport gap with a corresponding energy of ~60 meV. This is an important step towards fast and reliable patterning of suspended graphene for future ballistic transport, nano-electronic and nano-mechanical devices. PMID:25586495

  20. Scalable Transfer of Suspended Two-Dimensional Single Crystals.

    PubMed

    Li, Bo; He, Yongmin; Lei, Sidong; Najmaei, Sina; Gong, Yongji; Wang, Xin; Zhang, Jing; Ma, Lulu; Yang, Yingchao; Hong, Sanghyun; Hao, Ji; Shi, Gang; George, Antony; Keyshar, Kunttal; Zhang, Xiang; Dong, Pei; Ge, Liehui; Vajtai, Robert; Lou, Jun; Jung, Yung Joon; Ajayan, Pulickel M

    2015-08-12

    Large-scale suspended architectures of various two-dimensional (2D) materials (MoS2, MoSe2, WS2, and graphene) are demonstrated on nanoscale patterned substrates with different physical and chemical surface properties, such as flexible polymer substrates (polydimethylsiloxane), rigid Si substrates, and rigid metal substrates (Au/Ag). This transfer method represents a generic, fast, clean, and scalable technique to suspend 2D atomic layers. The underlying principle behind this approach, which employs a capillary-force-free wet-contact printing method, was studied by characterizing the nanoscale solid-liquid-vapor interface of 2D layers with respect to different substrates. As a proof-of-concept, a photodetector of suspended MoS2 has been demonstrated with significantly improved photosensitivity. This strategy could be extended to several other 2D material systems and open the pathway toward better optoelectronic and nanoelectromechnical systems.

  1. Nano-superconducting quantum interference devices with suspended junctions

    SciTech Connect

    Hazra, D.; Hasselbach, K.; Kirtley, J. R.

    2014-04-14

    Nano-Superconducting Quantum Interference Devices (nano-SQUIDs) are usually fabricated from a single layer of either Nb or Al. We describe here a simple method for fabricating suspended nano-bridges in Nb/Al thin-film bilayers. We use these suspended bridges, which act as Josephson weak links, to fabricate nano-SQUIDs which show critical current oscillations at temperatures up to 1.5 K and magnetic flux densities up to over 20 mT. These nano-SQUIDs exhibit flux modulation depths intermediate between all-Al and all-Nb devices, with some of the desirable characteristics of both. The suspended geometry is attractive for magnetic single nanoparticle measurements.

  2. Longitudinal dispersion in open channel flow with suspended canopies.

    PubMed

    Huai, Wenxin; Li, Chengguang

    2016-01-01

    Suspended canopies can cause flow disturbances such as reducing velocities within the canopy, and increasing flow beneath the canopy. Flow modifications by canopies dramatically affect the fate and transport of sediment, nutrients, contaminants, dissolved oxygen, and fauna in aquatic systems. A three-zone model is presented here to predict the longitudinal dispersion coefficient by simplifying Chikwendu's N-zone model. To validate the model, both flow field and tracer experiments were conducted using a straight rectangular Plexiglas flume, with rigid circular rods as the modeled suspended canopies. The result shows that velocities increased above the flume bed and maximized at a point between the canopies and flume bed. Above that point, streamwise velocities decreased into and within the canopies. Reynolds shear stresses were largest at the canopy interface and smallest (zero) at the velocity maximum point. Good agreement between the modeled results and experimental data shows that the model can effectively predict the longitudinal dispersion coefficient in open channels with suspended canopies.

  3. Flywheel Energy Storage System Suspended by Hybrid Magnetic Bearing

    NASA Astrophysics Data System (ADS)

    Owusu-Ansah, Prince; Hu, Yefa; Misbawu, Adam

    This work presents a prototype flywheel energy storage system (FESS) suspended by hybrid magnetic bearing (HMB) rotating at a speed of 20000rpm with a maximum storage power capacity of 30W with a maximum tip speed of 300m/s. The design presented is an improvement of most existing FESS, as the design incorporates a unique feature in that the upper and the lower rotor and stator core are tapered which enhances larger thrust and much lower radial force to be exerted on the system. Without any adverse effect being experienced by the model. The work also focuses on the description of developing a prototype FESS suspended by HMB using solid works as a basis of developing in the nearer future a more improved FESS suspended by HMB capable of injecting the ever increasing high energy demand situation in the 21st century and beyond.

  4. Mechanical oscillations enhance gene delivery into suspended cells

    PubMed Central

    Zhou, Z. L.; Sun, X. X.; Ma, J.; Man, C. H.; Wong, A. S. T.; Leung, A. Y.; Ngan, A. H. W.

    2016-01-01

    Suspended cells are difficult to be transfected by common biochemical methods which require cell attachment to a substrate. Mechanical oscillations of suspended cells at certain frequencies are found to result in significant increase in membrane permeability and potency for delivery of nano-particles and genetic materials into the cells. Nanomaterials including siRNAs are found to penetrate into suspended cells after subjecting to short-time mechanical oscillations, which would otherwise not affect the viability of the cells. Theoretical analysis indicates significant deformation of the actin-filament network in the cytoskeleton cortex during mechanical oscillations at the experimental frequency, which is likely to rupture the soft phospholipid bilayer leading to increased membrane permeability. The results here indicate a new method for enhancing cell transfection. PMID:26956215

  5. Space charge neutralization by electron-transparent suspended graphene

    PubMed Central

    Srisonphan, Siwapon; Kim, Myungji; Kim, Hong Koo

    2014-01-01

    Graphene possesses many fascinating properties originating from the manifold potential for interactions at electronic, atomic, or molecular levels. Here we report measurement of electron transparency and hole charge induction response of a suspended graphene anode on top of a void channel formed in a SiO2/Si substrate. A two-dimensional (2D) electron gas induced at the oxide interface emits into air and makes a ballistic transport toward the suspended graphene. A small fraction (>~0.1%) of impinging electrons are captured at the edge of 2D hole system in graphene, demonstrating good transparency to very low energy (<3 eV) electrons. The hole charges induced in the suspended graphene anode have the effect of neutralizing the electron space charge in the void channel. This charge compensation dramatically enhances 2D electron gas emission at cathode to the level far surpassing the Child-Langmuir's space-charge-limited emission. PMID:24441774

  6. Forced oscillations of nonlinear damped equation of suspended string

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Masaru; Nagai, Tohru; Matsukane, Katsuya

    2008-06-01

    We shall study the existence of time-periodic solutions of nonlinear damped equation of suspended string to which a periodic nonlinear force works. We shall be conterned with weak, strong and classical time-periodic solutions and also the regularity of the solutions. To formulate our results, we shall take suitable weighted Sobolev-type spaces introduced by [M. Yamaguchi, Almost periodic oscillations of suspended string under quasiperiodic linear force, J. Math. Anal. Appl. 303 (2) (2005) 643-660; M. Yamaguchi, Infinitely many time-periodic solutions of nonlinear equation of suspended string, Funkcial. Ekvac., in press]. We shall study properties of the function spaces and show inequalities on the function spaces. To show our results we shall apply the Schauder fixed point theorem and the fixed point continuation theorem in the function spaces.

  7. Laboratory experiments on stratified flow through a suspended porous fence

    NASA Astrophysics Data System (ADS)

    Delavan, Sarah; Nokes, Roger; Plew, David

    2012-11-01

    This study explores stratified flow through a suspended, porous, fence-like obstacle to simulate flow through fish farm cages, mussel farm rope suspensions, flow through suspended aquatic vegetation, underwater energy production structures, or windbreak and wave break fencing. Laboratory experiments were performed in a density stratified, stationary flume with a suspended porous fence model using a particle tracking velocimetry (PTV) system. Experiments explored the effect on the fluid of the fence depth to total depth ratio, the system Richardson number, and the porosity of the fence. Preliminary results suggest that the density stratification of the fluid inhibits vertical fluid motion, that fence porosity greatly controls the vertical mixing of the fluid, and that there may be an optimal fence depth to total depth ratio for full development of the system flow structures.

  8. Mapping the nanomechanical properties of graphene suspended on silica nanoparticles

    NASA Astrophysics Data System (ADS)

    Osváth, Z.; Gergely-Fülöp, E.; Deák, A.; Hwang, C.; Biró, L. P.

    2016-09-01

    Using nanoparticles to impart extrinsic rippling in graphene is a relatively new method to induce strain and to tailor the properties of graphene. Here we study the structure and elastic properties of graphene grown by chemical vapour deposition and transferred onto a continuous layer of SiO2 nanoparticles with diameters of around 25 nm, prepared by Langmuir-Blodgett technique on Si substrate. We show that the transferred graphene follows only roughly the morphology induced by nanoparticles. The graphene membrane parts bridging the nanoparticles are suspended and their adhesion to the AFM tip is larger compared to that of supported graphene parts. These suspended graphene regions can be deformed with forces of the order of 10 nN. The elastic modulus of graphene was determined from indentation measurements performed on suspended membrane regions with diameters in the 100 nm range.

  9. System for concentrating and analyzing particles suspended in a fluid

    DOEpatents

    Fiechtner, Gregory J.; Cummings, Eric B.; Singh, Anup K.

    2011-04-26

    Disclosed is a device for separating and concentrating particles suspended in a fluid stream by using dielectrophoresis (DEP) to trap and/or deflect those particles as they migrate through a fluid channel. The method uses fluid channels designed to constrain a liquid flowing through it to uniform electrokinetic flow velocities. This behavior is achieved by connecting deep and shallow sections of channels, with the channel depth varying abruptly along an interface. By careful design of abrupt changes in specific permeability at the interface, an abrupt and spatially uniform change in electrokinetic force can be selected. Because these abrupt interfaces also cause a sharp gradient in applied electric fields, a DEP force also can be established along the interface. Depending on the complex conductivity of the suspended particles and the immersion liquid, the DEP force can controllably complement or oppose the local electrokinetic force transporting the fluid through the channel allowing for manipulation of particles suspended in the transporting liquid.

  10. The distribution of suspended matter in the Dutch coastal zone

    NASA Astrophysics Data System (ADS)

    Visser, M.; de Ruijter, W. P. M.; Postma, L.

    Results are presented of suspended matter observations taken at bi-weekly intervals during the period 1975-1983, in a strip 70 km wide along the Dutch coast. The average distribution showed a (weak) minimum zone located north of Noordwijk at a distance of about 30 km from and parallel to the Dutch coast, between the salinity maximum and the coast. Variability was large between different years, seasons and individual cruises. A clear seasonal cycle emerged from the observed suspended-matter patterns: in winter a pronounced minimum existed, while in summer generally a monotonically decreasing concentration was measured, to open-sea values much lower than in winter. This seasonal cycle may be explained by a combination of variation in wind, river discharge and the activity of suspended-matter sources. The Flemish Banks and Channel waters are the main sources supplying suspended matter to the Dutch coastal area. Especially the varying transport through the Strait of Dover, large in winter, small in summer, determines the seasonal variation in the total amount of suspended matter. The existence of a localized turbidity minimum is tied to relatively large discharges from the Rhine and associated steep salinity gradients, also occurring mainly in winter and early spring. A simple model of cross-shore density-driven circulation shows the possible influence of the strong salinity gradients on the sedimentation of suspended matter. Particles with a settling rate comparable to the vertical velocity component of the circulation are forced to move offshore until they reach an area they sink out of the surface layer. The strength of this circulation is determined by the cross-shore density gradient due to the inflow of fresh water from the Rhine-Meuse estuary.

  11. Sources of suspended sediment in the Lower Roanoke River, NC

    NASA Astrophysics Data System (ADS)

    Jalowska, A. M.; McKee, B. A.; Rodriguez, A. B.; Laceby, J. P.

    2015-12-01

    The Lower Roanoke River, NC, extends 220 km from the fall line to the bayhead delta front in the Albemarle Sound. The Lower Roanoke is almost completely disconnected from the upper reaches by a series of dams, with the furthest downstream dam located at the fall line. The dams effectively restrict the suspended sediment delivery from headwaters, making soils and sediments from the Lower Roanoke River basin, the sole source of suspended sediment. In flow-regulated rivers, bank erosion, especially mass wasting, is the major contributor to the suspended matter. Additional sources of the suspended sediment considered in this study are river channel, surface soils, floodplain surface sediments, and erosion of the delta front and prodelta. Here, we examine spatial and temporal variations in those sources. This study combined the use of flow and grain size data with a sediment fingerprinting method, to examine the contribution of surface and subsurface sediments to the observed suspended sediment load along the Lower Roanoke River. The fingerprinting method utilized radionuclide tracers 210Pb (natural atmospheric fallout), and 137Cs (produced by thermonuclear bomb testing). The contributions of surface and subsurface sources to the suspended sediment were calculated with 95% confidence intervals using a Monte-Carlo numerical mixing model. Our results show that with decreasing river slope and changing hydrography along the river, the contribution of surface sediments increases and becomes a main source of sediments in the Roanoke bayhead delta. At the river mouth, the surface sediment contribution decreases and is replaced by sediments eroded from the delta front and prodelta. The area of high surface sediment contribution is within the middle and upper parts of the delta, which are considered net depositional. Our study demonstrates that floodplains, often regarded to be a sediment sink, are also a sediment source, and they should be factored into sediment, carbon and

  12. Optimal estimation of suspended-sediment concentrations in streams

    USGS Publications Warehouse

    Holtschlag, D.J.

    2001-01-01

    Optimal estimators are developed for computation of suspended-sediment concentrations in streams. The estimators are a function of parameters, computed by use of generalized least squares, which simultaneously account for effects of streamflow, seasonal variations in average sediment concentrations, a dynamic error component, and the uncertainty in concentration measurements. The parameters are used in a Kalman filter for on-line estimation and an associated smoother for off-line estimation of suspended-sediment concentrations. The accuracies of the optimal estimators are compared with alternative time-averaging interpolators and flow-weighting regression estimators by use of long-term daily-mean suspended-sediment concentration and streamflow data from 10 sites within the United States. For sampling intervals from 3 to 48 days, the standard errors of on-line and off-line optimal estimators ranged from 52.7 to 107%, and from 39.5 to 93.0%, respectively. The corresponding standard errors of linear and cubic-spline interpolators ranged from 48.8 to 158%, and from 50.6 to 176%, respectively. The standard errors of simple and multiple regression estimators, which did not vary with the sampling interval, were 124 and 105%, respectively. Thus, the optimal off-line estimator (Kalman smoother) had the lowest error characteristics of those evaluated. Because suspended-sediment concentrations are typically measured at less than 3-day intervals, use of optimal estimators will likely result in significant improvements in the accuracy of continuous suspended-sediment concentration records. Additional research on the integration of direct suspended-sediment concentration measurements and optimal estimators applied at hourly or shorter intervals is needed.

  13. Dynamic transport of suspended sediment by solitary wave: Experimental study

    NASA Astrophysics Data System (ADS)

    cho, JaeNam; Kim, DongHyun; Hwang, KyuNam; Lee, SeungOh

    2016-04-01

    Solitary waves are able to transport a large amount of suspended sediment when approaching on the beach, which sometimes causes - serious beach erosion, especially in the east and south coastal lines in Korea. But it has rarely been known about the method how to evaluate or estimate the amount of beach erosion caused by solitary waves. Experimental assessment is necessary to comprehend the process of sediment transport on a slope. The prismatic rectangular channel is 12 m long, 0.8 m wide, and 0.75 m high. A sluice gate is applied at prismatic channel in order to produce the solitary waves. Upstream water depth is more than channel water depth and the sluice gate is suddenly opened to simulate conditions of solitary waves. A sand slope with a 1/6 and a sediment thickness is 0.03 m. The experimental sediments are used anthracite (d_50=1.547 mm ,C_u=1.38) and Jumoonjin sand (d_50=0.627 mm ,C_u=1.68). Specific laboratory equipment are designed to collect suspended sediment samples at the same time along the wave propagation at 5 points with evenly space. Each amount of sampling is approximately 25 ml and they are completely dried in oven over 24 hours according to the USGS (Guideline and standard techniques and method 3-C4). Two video cameras (Model No. : Sony, HDR-XR550) are mounted for capturing images at top and side-view when the processes of solitary wave and run up/down on slope. Also, this study are analyzed the correlation between Suspended sediment concentration and turbidity. Also, this study are analyzed the correlation between suspended sediment concentration and turbidity. Turbidity is used to verify suspended sediment concentration. Dimensionless analyses of experimental results carried out in this study. One dimensionless parameter is expressed with pressure of solitary wave on a slope to suspended sediment concentration, which is concerned about lifting force. The other is relate to drag force presenting with run up/down velocity on a slope and

  14. Superior thermal conductivity in suspended bilayer hexagonal boron nitride

    NASA Astrophysics Data System (ADS)

    Wang, Chengru; Guo, Jie; Dong, Lan; Aiyiti, Adili; Xu, Xiangfan; Li, Baowen

    2016-05-01

    We reported the basal-plane thermal conductivity in exfoliated bilayer hexagonal boron nitride h-BN that was measured using suspended prepatterned microstructures. The h-BN sample suitable for thermal measurements was fabricated by dry-transfer method, whose sample quality, due to less polymer residues on surfaces, is believed to be superior to that of PMMA-mediated samples. The measured room temperature thermal conductivity is around 484 Wm‑1K‑1(+141 Wm‑1K‑1/ ‑24 Wm‑1K‑1) which exceeds that in bulk h-BN, providing experimental observation of the thickness-dependent thermal conductivity in suspended few-layer h-BN.

  15. Single-molecule diffusion in freely suspended smectic films.

    PubMed

    Schulz, Benjamin; Mazza, Marco G; Bahr, Christian

    2014-10-01

    We present a study of the molecular diffusion in freely suspended smectic-A liquid crystal films with thicknesses ranging from 20 down to only two molecular layers. The molecular mobility is directly probed by determining the trajectories of single, fluorescent tracer molecules. We demonstrate, using several different smectic compounds, that a monotonic increase of the diffusion coefficient with decreasing film thickness is a general phenomenon. In two-layer films, the diffusion is enhanced by a factor of 3 to 5 compared to the corresponding bulk smectic phase. Molecular dynamics simulations of freely suspended smectic films are presented which support the experimental results.

  16. Effect of strain on thermoelectric power of suspended graphene

    SciTech Connect

    Vaidya, R. G.; Sankeshwar, N. S. Mulimani, B. G.

    2013-12-04

    Thermoelectric power, S, of suspended graphene in the presence of strain is investigated. The electrons are considered to be scattered by in-plane and flexural phonons. The dominant contribution to S of non-strained and strained suspended graphene (SG) is found to be from the phonon drag component, S{sub g} for T < 90K. For T > 150 K contribution from diffusion thermopower becomes important. The effect of strain is found to be suppress S{sub d} and to alter its behavior, the effect being larger at higher temperatures.

  17. 14 CFR 1261.416 - Suspending or terminating collection action.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... CFR 105.2(b). If NASA decides not to suspend or terminate collection action on the claim, Department... (see 4 CFR 102.18); other Federal agencies; employers, relatives, friends; credit agency skip locate... made primarily to delay collection. See 4 CFR 104.2. (d) Termination of collection activity....

  18. Calamine lotion: experimenting with a new suspending agent.

    PubMed

    Al-Achi, A; Greenwood, R; Akin-Isijola, A; Bullard, J

    1999-01-01

    The use of a new suspending agent is investigated. Calamine lotion, USP contains bentonite magma as a suspending agent. In this study, bentonite magma was partially or completely replaced with a new suspending agent called tahini. Tahini is sesame paste composed of crushed sesame seeds in sesame oil. It is frequently used in middle eastern food as a thickening and suspending agent. Calamine lotion was prepared, generally, according to the USP method. The formula contained 40% v/v magma. Tahini was added instead of bentonite magma by replacing 100%, 99%, 90%, 75%, 50% and 25% of the magma. The sedimentation volume and the degree of flocculation were calculated for the resulting preparations. Rheological characteristics of bentonite- and tahini-containing lotions were also determined. Sedimentation volume showed 0.723 and 0.851 (p=0.05) for the lotions containing 100% bentonite and 100% tahini, respectively. The degree of flocculation was 2.00 and 2.35 (p=0.05) for the 100% bentonite and 100% tahini lotions, respectively. The rheograms of all the suspensions showed pseudoplastic flow. Overall, the use of tahini in calamine lotion has improved the physical stability of the formula.

  19. Simultaneous removal of ammonium and suspended solids in multipurpose filters.

    PubMed

    Alkas, Deniz; Baykal, Bilsen Beler; Kinaci, Cumali

    2012-06-01

    A multipurpose filter in which sand and clinoptilolite are used together as filter material is suggested for the simultaneous removal of suspended solids and ammonium in one single unit. The capacity of the clinoptilolite used was determined as 10.4 mg/g for 20 mg/l initial ammonium concentration. In addition, a packed column ion exchanger with clinoptilolite and a classical sand filter were also investigated for comparison. Ammonium and suspended solids removal rates were observed and compared for all columns. The results of the column analysis have revealed that the ammonium removal rate, which was only 20% in the sand column, was increased to 100% by replacing 50% of the sand with clinoptilolite; similarly, the suspended solids removal, which was only 17% in the clinoptilolite column, was increased to 75% by replacing 50% of the clinoptilolite with sand. As such, when ion exchange and filtration processes were carried out in a multipurpose column, high removals for both parameters could be obtained simultaneously. Multipurpose columns could be an alternative both for the upgrading of existing treatment plants or for new plants for simultaneous removal of ammonium and suspended solids, giving considerable savings in terms of land requirements.

  20. SEPARATING URANIUM CONTAINING SOLIDS SUSPENDED IN A LIQUID

    DOEpatents

    Creutz, E.C.; Wigner, E.P.

    1958-05-01

    A process is described for separating uraniumcontaining solids suspended in a liquid. It consists of adding to the liquid a wetting agent for the U- containing solids in an amount sufficient to form a separate liquid phase, the wetting agent having a density greater than the density of the liquid. Ethyl dibromoacetate is noted as one preferred wetting agent.

  1. Suspended Education Department Official Had Approved Waiver for Former Employer

    ERIC Educational Resources Information Center

    Basken, Paul

    2007-01-01

    Matteo Fontana, the student-aid official in the U.S. Department of Education who was suspended last month in an ethics case, issued a controversial high-stakes legal ruling in 2004 that benefited his former employer, Sallie Mae, on the day before the nation's top student lender completed its transition from a government-founded lender into a…

  2. 14 CFR 1261.416 - Suspending or terminating collection action.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... CFR 105.2(b). If NASA decides not to suspend or terminate collection action on the claim, Department... sufficiently productive to justify periodic review and action on the claim, with due consideration for the size... (see 4 CFR 102.18); other Federal agencies; employers, relatives, friends; credit agency skip...

  3. 7 CFR 160.53 - Stopping inspection by suspended inspector.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Stopping inspection by suspended inspector. 160.53 Section 160.53 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING... REGULATIONS AND STANDARDS FOR NAVAL STORES Request Inspection by Licensed Inspectors § 160.53...

  4. 7 CFR 160.53 - Stopping inspection by suspended inspector.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Stopping inspection by suspended inspector. 160.53 Section 160.53 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING... REGULATIONS AND STANDARDS FOR NAVAL STORES Request Inspection by Licensed Inspectors § 160.53...

  5. 7 CFR 160.53 - Stopping inspection by suspended inspector.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Stopping inspection by suspended inspector. 160.53 Section 160.53 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING... REGULATIONS AND STANDARDS FOR NAVAL STORES Request Inspection by Licensed Inspectors § 160.53...

  6. 7 CFR 160.53 - Stopping inspection by suspended inspector.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Stopping inspection by suspended inspector. 160.53 Section 160.53 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING... REGULATIONS AND STANDARDS FOR NAVAL STORES Request Inspection by Licensed Inspectors § 160.53...

  7. 7 CFR 160.53 - Stopping inspection by suspended inspector.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Stopping inspection by suspended inspector. 160.53 Section 160.53 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING... REGULATIONS AND STANDARDS FOR NAVAL STORES Request Inspection by Licensed Inspectors § 160.53...

  8. PROCEEDINGS OF A WORKSHOP ON SUSPENDED SEDIMENTS AND SOLIDS

    EPA Science Inventory

    The Workshop on Suspended Sediments and Solids was held on July 11-12, 2002 in Cincinnati, Ohio. The workshop was conducted by the U.S. Environmental Protection Agency's (USEPA) National Risk Management Research Laboratory (NRMRL). Representatives from NRMRL Divisions; other USEP...

  9. 14 CFR 1261.416 - Suspending or terminating collection action.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... CFR 105.2(b). If NASA decides not to suspend or terminate collection action on the claim, Department... (see 4 CFR 102.18); other Federal agencies; employers, relatives, friends; credit agency skip locate... made primarily to delay collection. See 4 CFR 104.2. (d) Termination of collection activity....

  10. 14 CFR 1261.416 - Suspending or terminating collection action.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... CFR 105.2(b). If NASA decides not to suspend or terminate collection action on the claim, Department... (see 4 CFR 102.18); other Federal agencies; employers, relatives, friends; credit agency skip locate... made primarily to delay collection. See 4 CFR 104.2. (d) Termination of collection activity....

  11. 22. Detail view of sign suspended from portal strut (this ...

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

    22. Detail view of sign suspended from portal strut (this sign was located at the same place at both ends of Moody Bridge). Bottom: General elevation view to southeast showing northern abutment with solid rock foundation. - Moody Bridge, Spanning South Fork Eel River, Garberville, Humboldt County, CA

  12. 6 CFR 11.12 - Suspending or terminating collection activity.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 6 Domestic Security 1 2011-01-01 2011-01-01 false Suspending or terminating collection activity. 11.12 Section 11.12 Domestic Security DEPARTMENT OF HOMELAND SECURITY, OFFICE OF THE SECRETARY CLAIMS... activity, or discharge indebtedness, in accordance with 31 CFR part 903. The Chief Financial Officer...

  13. 6 CFR 11.12 - Suspending or terminating collection activity.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 6 Domestic Security 1 2012-01-01 2012-01-01 false Suspending or terminating collection activity. 11.12 Section 11.12 Domestic Security DEPARTMENT OF HOMELAND SECURITY, OFFICE OF THE SECRETARY CLAIMS... activity, or discharge indebtedness, in accordance with 31 CFR part 903. The Chief Financial Officer...

  14. Suspended sediments of the modern Amazon and Orinoco rivers

    USGS Publications Warehouse

    Meade, R.H.

    1994-01-01

    The Amazon and Orinoco Rivers are massive transcontinental conveyance systems for suspended sediment. They derive about 90% of their sediment from the Andes that support their western headwaters, transport it for thousands of kilometers across the breadth of the continent and deposit it in the coastal zones of the Atlantic. At their points of maximum suspended-sediment discharge, the Amazon transports an average of 1100-1300 ?? 106 tons per year and the Orinoco transports about 150 ?? 106 tons per year. Relations of sediment discharge to water discharge are complicated by unusual patterns of seasonal storage and remobilization, increased storage and reduced transport of sediment in the middle Orinoco during periods of peak water discharge, and storage of suspended sediment in the lower Amazon during rising discharge and resuspension during falling discharge. Spatial distributions of suspended sediment in cross-sections of both rivers are typically heterogeneous, not only in the vertical sense but also in the lateral. The cross-channel mixing of tributary inputs into the mainstem waters is a slow process that requires several hundred kilometers of downriver transport to complete. Considerable fine-grained sediment is exchanged between rivers and floodplains by the combination of overbank deposition and bank erosion. ?? 1994.

  15. 14 CFR 221.211 - Cancellation of suspended matter.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Cancellation of suspended matter. 221.211 Section 221.211 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION... matter. When, pursuant to an order of the Department, the cancellation of rules, fares, charges, or...

  16. 14 CFR 221.211 - Cancellation of suspended matter.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Cancellation of suspended matter. 221.211 Section 221.211 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION... matter. When, pursuant to an order of the Department, the cancellation of rules, fares, charges, or...

  17. 14 CFR 221.211 - Cancellation of suspended matter.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Cancellation of suspended matter. 221.211 Section 221.211 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION... matter. When, pursuant to an order of the Department, the cancellation of rules, fares, charges, or...

  18. 14 CFR 221.211 - Cancellation of suspended matter.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Cancellation of suspended matter. 221.211 Section 221.211 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION... matter. When, pursuant to an order of the Department, the cancellation of rules, fares, charges, or...

  19. 14 CFR 221.211 - Cancellation of suspended matter.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Cancellation of suspended matter. 221.211 Section 221.211 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION... matter. When, pursuant to an order of the Department, the cancellation of rules, fares, charges, or...

  20. Electrostatically suspended and sensed micro-mechanical rate gyroscope

    NASA Technical Reports Server (NTRS)

    Torti, R.; Gerver, M.; Gondhalekar, V.; Bart, S.; Maxwell, B.

    1994-01-01

    The goal of this work is development of fully electrostatically suspended and rebalancing angular rate sensing micro-gyroscope fabricated according to standard VLSI techniques. Fabrication of test structures is proceeding. Off chip electronics for the electrostatic sensing and driving circuits has been tested. The prototype device will be assembled in a hybrid construction including the FET input stages of the sensors.

  1. Opportunities Suspended: The Disparate Impact of Disciplinary Exclusion from School

    ERIC Educational Resources Information Center

    Losen, Daniel J.; Gillespie, Jonathan

    2012-01-01

    Well over three million children, K-12, are estimated to have lost instructional "seat time" in 2009-2010 because they were suspended from school, often with no guarantee of adult supervision outside the school. That's about the number of children it would take to fill every seat in every major league baseball park and every NFL stadium…

  2. DEVELOPING WATER QUALITY CRITERIA FOR SUSPENDED AND BEDDED SEDIMENTS

    EPA Science Inventory

    The U.S. EPA’s Framework for Developing Suspended and Bedded Sediments (SABS) Water Quality Criteria (SABS Framework) is a nationally-consistent process for developing ambient sediment quality criteria for surface waters. The SABS Framework accommodates natural variation among wa...

  3. Is There an Educational Penalty for Being Suspended from School?

    ERIC Educational Resources Information Center

    Cobb-Clark, Deborah A.; Kassenboehmer, Sonja C.; Le, Trinh; McVicar, Duncan; Zhang, Rong

    2015-01-01

    Suspension from school is a commonly used, yet controversial, school disciplinary measure. This paper uses unique survey data to estimate the impact of suspension on the educational outcomes of those suspended. It finds that while suspension is strongly associated with educational outcomes, the relationship is unlikely to be causal, but rather…

  4. Suspended sediment modeling using genetic programming and soft computing techniques

    NASA Astrophysics Data System (ADS)

    Kisi, Ozgur; Dailr, Ali Hosseinzadeh; Cimen, Mesut; Shiri, Jalal

    2012-07-01

    SummaryModeling suspended sediment load is an important factor in water resources engineering as it crucially affects the design and management of water resources structures. In this study the genetic programming (GP) technique was applied for estimating the daily suspended sediment load in two stations in Cumberland River in U.S. Daily flow and sediment data from 1972 to 1989 were used to train and test the applied genetic programming models. The effect of various GP operators on sediment load estimation was investigated. The optimal fitness function, operator functions, linking function and learning algorithm were obtained for modeling daily suspended sediment. The GP estimates were compared with those of the Adaptive Neuro-Fuzzy Inference System (ANFIS), Artificial Neural Networks (ANNs) and Support Vector Machine (SVM) results, in term of coefficient of determination, mean absolute error, coefficient of residual mass and variance accounted for. The comparison results indicated that the GP is superior to the ANFIS, ANN and SVM models in estimating daily suspended sediment load.

  5. 40 CFR 52.330 - Control strategy: Total suspended particulates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: Total suspended particulates. 52.330 Section 52.330 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Colorado § 52.330 Control...

  6. 40 CFR 52.330 - Control strategy: Total suspended particulates.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Control strategy: Total suspended particulates. 52.330 Section 52.330 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Colorado § 52.330 Control...

  7. Suspending Insoluble Solids Waste Tanks with Shrouded Axial Impeller Mixers

    SciTech Connect

    Poirier, M.R.

    1998-11-09

    The Savannah River Site is in the process of removing waste (sludge and salt cake) from million gallon waste tanks. The authors are conducted a test program to determine mixer requirements for suspending sludge heels using shrouded axial impeller mixers. The authors will present and discuss the data generated during the tests.

  8. 20. Photographic copy of photograph of roof suspender system taken ...

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

    20. Photographic copy of photograph of roof suspender system taken on March 22, 1957. Photographer unknown. Original photograph property of the City of Philadelphia, Division of Aviation. Reprinted with permission of the Division of Aviation. - TWA Maintenance Hangar, South side of Tinicum Island Road, Philadelphia International Airport, Philadelphia, Philadelphia County, PA

  9. Vibrotactile evaluation: osseointegrated versus socket-suspended transfemoral prostheses.

    PubMed

    Häggström, Eva; Hagberg, Kerstin; Rydevik, Björn; Brånemark, Rickard

    2013-01-01

    This study investigated detection thresholds of vibrometric stimuli in patients with transfemoral amputation supplied with osseointegrated (OI) and socket-suspended prostheses. It included 17 patients tested preoperatively with socket-suspended prostheses and after 2 yr with OI prostheses and a control group (n = 17) using socket-suspended prostheses, evaluated once. Assessments on the prosthetic and intact feet were conducted at six frequencies (8, 16, 32, 64, 125, and 250 Hz). Furthermore, measurements were conducted to investigate how vibrometric signals are transmitted through a test prosthesis. The results showed that the OI group had improved ability to detect vibrations through the prosthesis at 125 Hz (p = 0.01) at follow-up compared with the preoperative measurement. Compared with the control group, the OI group at follow-up had better ability to detect high frequency vibrations through the prosthesis (125 Hz, p = 0.02; 250 Hz, p = 0.03). The vibrometric signal transmitted through the test prosthesis was reduced at 8, 125, and 250 Hz but was amplified at 16, 32, and 64 Hz. Differences between the OI and the control groups were found in the highest frequencies in which the test prosthesis showed reduction of the vibrometric signal. The study provides insight into the mechanisms of vibration transmission between the exterior and bone-anchored as well as socket-suspended amputation prostheses.

  10. 40 CFR 52.330 - Control strategy: Total suspended particulates.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Colorado § 52.330 Control strategy: Total suspended particulates. (a) Part D—Conditional Approval: The Pueblo plan is approved assuming the... will be published in the Colorado Register by March 10, 1981. (3) Public hearing will be held by May...

  11. 40 CFR 52.330 - Control strategy: Total suspended particulates.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Colorado § 52.330 Control strategy: Total suspended particulates. (a) Part D—Conditional Approval: The Pueblo plan is approved assuming the... will be published in the Colorado Register by March 10, 1981. (3) Public hearing will be held by May...

  12. 40 CFR 52.330 - Control strategy: Total suspended particulates.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Colorado § 52.330 Control strategy: Total suspended particulates. (a) Part D—Conditional Approval: The Pueblo plan is approved assuming the... will be published in the Colorado Register by March 10, 1981. (3) Public hearing will be held by May...

  13. 10 CFR 15.53 - Reasons for suspending collection action.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Reasons for suspending collection action. 15.53 Section 15.53 Energy NUCLEAR REGULATORY COMMISSION DEBT COLLECTION PROCEDURES Suspension or Termination of... future prospects justify retention of the debt for periodic review and collection activity and: (1)...

  14. A Buoy for Continuous Monitoring of Suspended Sediment Dynamics

    PubMed Central

    Mueller, Philip; Thoss, Heiko; Kaempf, Lucas; Güntner, Andreas

    2013-01-01

    Knowledge of Suspended Sediments Dynamics (SSD) across spatial scales is relevant for several fields of hydrology, such as eco-hydrological processes, the operation of hydrotechnical facilities and research on varved lake sediments as geoarchives. Understanding the connectivity of sediment flux between source areas in a catchment and sink areas in lakes or reservoirs is of primary importance to these fields. Lacustrine sediments may serve as a valuable expansion of instrumental hydrological records for flood frequencies and magnitudes, but depositional processes and detrital layer formation in lakes are not yet fully understood. This study presents a novel buoy system designed to continuously measure suspended sediment concentration and relevant boundary conditions at a high spatial and temporal resolution in surface water bodies. The buoy sensors continuously record turbidity as an indirect measure of suspended sediment concentrations, water temperature and electrical conductivity at up to nine different water depths. Acoustic Doppler current meters and profilers measure current velocities along a vertical profile from the water surface to the lake bottom. Meteorological sensors capture the atmospheric boundary conditions as main drivers of lake dynamics. It is the high spatial resolution of multi-point turbidity measurements, the dual-sensor velocity measurements and the temporally synchronous recording of all sensors along the water column that sets the system apart from existing buoy systems. Buoy data collected during a 4-month field campaign in Lake Mondsee demonstrate the potential and effectiveness of the system in monitoring suspended sediment dynamics. Observations were related to stratification and mixing processes in the lake and increased turbidity close to a catchment outlet during flood events. The rugged buoy design assures continuous operation in terms of stability, energy management and sensor logging throughout the study period. We conclude that

  15. A buoy for continuous monitoring of Suspended Sediment Dynamics.

    PubMed

    Mueller, Philip; Thoss, Heiko; Kaempf, Lucas; Güntner, Andreas

    2013-01-01

    Knowledge of Suspended Sediments Dynamics (SSD) across spatial scales is relevant for several fields of hydrology, such as eco-hydrological processes, the operation of hydrotechnical facilities and research on varved lake sediments as geoarchives. Understanding the connectivity of sediment flux between source areas in a catchment and sink areas in lakes or reservoirs is of primary importance to these fields. Lacustrine sediments may serve as a valuable expansion of instrumental hydrological records for flood frequencies and magnitudes, but depositional processes and detrital layer formation in lakes are not yet fully understood. This study presents a novel buoy system designed to continuously measure suspended sediment concentration and relevant boundary conditions at a high spatial and temporal resolution in surface water bodies. The buoy sensors continuously record turbidity as an indirect measure of suspended sediment concentrations, water temperature and electrical conductivity at up to nine different water depths. Acoustic Doppler current meters and profilers measure current velocities along a vertical profile from the water surface to the lake bottom. Meteorological sensors capture the atmospheric boundary conditions as main drivers of lake dynamics. It is the high spatial resolution of multi-point turbidity measurements, the dual-sensor velocity measurements and the temporally synchronous recording of all sensors along the water column that sets the system apart from existing buoy systems. Buoy data collected during a 4-month field campaign in Lake Mondsee demonstrate the potential and effectiveness of the system in monitoring suspended sediment dynamics. Observations were related to stratification and mixing processes in the lake and increased turbidity close to a catchment outlet during flood events. The rugged buoy design assures continuous operation in terms of stability, energy management and sensor logging throughout the study period. We conclude that

  16. The Use of Measured Suspended Sediment Concentrations at Alcatraz to Infer Net Suspended Sediment Transport at the Golden Gate

    NASA Astrophysics Data System (ADS)

    Erikson, L. H.; Wright, S. A.; Elias, E.; Hanes, D. M.; Schoellhamer, D. H.

    2012-12-01

    Numerical model simulations combined with physical measurements were used to estimate the net volumetric water and suspended sediment flux at teh Golden Gate between San Francisco Bay and the coastal ocean. Measurements were obtained using vessel-mounted acoustic Doppler current profilers and semi-empirical calibrations between backscatter intensity and in situ suspended-sediment concentrations throughout the water column. Transects across the inlet were repeated continuously for >12 h during both spring and neap tides to provide near-synoptic measurements over full tidal cycles. A numerical model was validated against volumetric water flux and calibrated against sediment flux measurements which were then used to estimate net sediment exchange. The product of current vectors computed with a numerical model and synoptic measurements of suspended- sediment concentrations at the nearby continuous monitoring site on Alcatraz Island showed reasonable correlation with tide-averaged sediment flux through the Gate; this provided a basis for the development of an analytical relationship to estimate suspended sediment flux through the Golden Gate using continuous measurements at Alcatraz as a proxy.

  17. Turbidity - a Semi-Continuous Monitoring Option for Suspended Solids

    NASA Astrophysics Data System (ADS)

    Lendvay, J. M.; Rosasco, M. V.; David, K. E.

    2012-12-01

    Redwood Creek, a third order coastal stream flowing through Muir Woods National Monument and Golden Gate National Recreation Area in Marin County, California, was once the spawning grounds for a relatively large population of Coho Salmon (Oncorhynchus kisutch). In recent years less than 1% of historic populations have been returning to the stream. Redwood creek is currently undergoing extensive ecological restoration in an attempt to improve the spawning habitat for the salmon. The original stream path has been altered in the past to make way for development and the National Park Service has been working towards restoring much of the stream's natural functionality with the hope that the salmon population will increase. The restoration process has altered the surrounding riparian landscape in the Redwood Creek watershed. Riparian disturbance caused by vegetation and levee removal as a part of the restoration process followed by installation of seedlings raises concern about the concentration of sediments in the water. Throughout 2011-2012 three parameters for water quality were monitored at Redwood Creek. Suspended sediment concentration (SSC) and total suspended solids (TSS) measurements to determine the concentration of suspended particles in the water column at a given point in time. Turbidity, measured in Nephelometric Turbidity Units (NTU) is a measure of the water's cloudiness caused by suspended particles. Turbidity measurements are favored as they provide a semi-automated monitoring option. Therefore, development of a relationship between turbidity and SSC and TSS is desired. Water samples were analyzed for TSS and SSC using the EPA standard methods, and Turbidity was measured using a Hach 2100Q portable turbidimeter. Additional semi-continuous monitoring of turbidity was completed in situ using Hydrolab DS5X datasondes (with self-cleaning turbidity sensor). The relationship between TSS, SSC and turbidity was determined using a linear regression model for

  18. ROLE OF SUSPENDED SEDIMENT IN SHORE-NORMAL BEACH PROFILE CHANGES.

    USGS Publications Warehouse

    Jaffe, Bruce E.; Sternberg, Richard W.; Sallgenger, Asbury H.; Edge, Billy L.

    1985-01-01

    Field measurements of suspended sediment-transport were made across a dissipative surf zone during a storm. A correlation between high suspended mass in the water column and periods of onshore flow caused a net onshore transport of suspended sediment even though the mean near-bottom flow was directed offshore. The observed onshore migration of a nearshore bar was predicted by gradients in the cross-shore suspended-sediment transport.

  19. Understanding hydrothermal transformation from Mn2O3 particles to Na0.55Mn2O4·1.5H2O nanosheets, nanobelts, and single crystalline ultra-long Na4Mn9O18 nanowires

    PubMed Central

    Park, Yohan; Woo Lee, Sung; Kim, Ki Hyeon; Min, Bong-Ki; Kumar Nayak, Arpan; Pradhan, Debabrata; Sohn, Youngku

    2015-01-01

    Manganese oxides are one of the most valuable materials for batteries, fuel cells and catalysis. Herein, we report the change in morphology and phase of as-synthesized Mn2O3 by inserting Na+ ions. In particular, Mn2O3 nanoparticles were first transformed to 2 nm thin Na0.55Mn2O4·1.5H2O nanosheets and nanobelts via hydrothermal exfoliation and Na cation intercalation, and finally to sub-mm ultra-long single crystalline Na4Mn9O18 nanowires. This paper reports the morphology and phase-dependent magnetic and catalytic (CO oxidation) properties of the as-synthesized nanostructured Na intercalated Mn-based materials. PMID:26667348

  20. 30 CFR 285.1014 - When will MMS suspend an Alternate Use RUE?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 2 2011-07-01 2011-07-01 false When will MMS suspend an Alternate Use RUE? 285... Facilities Alternate Use Rue Administration § 285.1014 When will MMS suspend an Alternate Use RUE? (a) The MMS may suspend an Alternate Use RUE if: (1) Necessary to comply with judicial decrees; (2)...

  1. 30 CFR 585.1014 - When will BOEM suspend an Alternate Use RUE?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 2 2012-07-01 2012-07-01 false When will BOEM suspend an Alternate Use RUE... Alternate Use Rue Administration § 585.1014 When will BOEM suspend an Alternate Use RUE? (a) BOEM may suspend an Alternate Use RUE if: (1) Necessary to comply with judicial decrees; (2) Continued...

  2. 30 CFR 585.1014 - When will BOEM suspend an Alternate Use RUE?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 2 2014-07-01 2014-07-01 false When will BOEM suspend an Alternate Use RUE... Alternate Use Rue Administration § 585.1014 When will BOEM suspend an Alternate Use RUE? (a) BOEM may suspend an Alternate Use RUE if: (1) Necessary to comply with judicial decrees; (2) Continued...

  3. 30 CFR 585.1014 - When will BOEM suspend an Alternate Use RUE?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 2 2013-07-01 2013-07-01 false When will BOEM suspend an Alternate Use RUE... Alternate Use Rue Administration § 585.1014 When will BOEM suspend an Alternate Use RUE? (a) BOEM may suspend an Alternate Use RUE if: (1) Necessary to comply with judicial decrees; (2) Continued...

  4. 30 CFR 285.1014 - When will MMS suspend an Alternate Use RUE?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false When will MMS suspend an Alternate Use RUE? 285... Rue Administration § 285.1014 When will MMS suspend an Alternate Use RUE? (a) The MMS may suspend an Alternate Use RUE if: (1) Necessary to comply with judicial decrees; (2) Continued activities pursuant...

  5. 13 CFR 103.3 - May SBA suspend or revoke an Agent's privilege?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false May SBA suspend or revoke an Agent... STANDARDS FOR CONDUCTING BUSINESS WITH SBA § 103.3 May SBA suspend or revoke an Agent's privilege? The Administrator of SBA or designee may, for good cause, suspend or revoke the privilege of any Agent to...

  6. 12 CFR 747.403 - Notice of intent to suspend or revoke charter; notice of suspension.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Notice of intent to suspend or revoke charter... to suspend or revoke charter; notice of suspension. (a) Upon its determination that one or more of... a notice of intent to suspend or revoke charter and of intent to place into involuntary...

  7. 27 CFR 1.35 - Authority to issue, amend, deny, suspend, revoke, or annul basic permits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., deny, suspend, revoke, or annul basic permits. 1.35 Section 1.35 Alcohol, Tobacco Products and Firearms..., deny, suspend, revoke, or annul basic permits. The authority and power of issuing, amending, or denying... of this chapter, may order the appropriate TTB officer to issue, deny, suspend, revoke, or...

  8. 33 CFR 148.320 - How is a license enforced, suspended, or revoked?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false How is a license enforced, suspended, or revoked? 148.320 Section 148.320 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF... enforced, suspended, or revoked? MARAD may enforce, suspend, or revoke a license under 33 U.S.C. 1507(c)....

  9. 7 CFR 61.38 - Suspended license to be returned to Division.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Suspended license to be returned to Division. 61.38...) Regulations Licensed Cottonseed Samplers § 61.38 Suspended license to be returned to Division. In case a license issued to a sampler is suspended or revoked such license shall be returned to the Division. At...

  10. Superior thermal conductivity in suspended bilayer hexagonal boron nitride

    PubMed Central

    Wang, Chengru; Guo, Jie; Dong, Lan; Aiyiti, Adili; Xu, Xiangfan; Li, Baowen

    2016-01-01

    We reported the basal-plane thermal conductivity in exfoliated bilayer hexagonal boron nitride h-BN that was measured using suspended prepatterned microstructures. The h-BN sample suitable for thermal measurements was fabricated by dry-transfer method, whose sample quality, due to less polymer residues on surfaces, is believed to be superior to that of PMMA-mediated samples. The measured room temperature thermal conductivity is around 484 Wm−1K−1(+141 Wm−1K−1/ −24 Wm−1K−1) which exceeds that in bulk h-BN, providing experimental observation of the thickness-dependent thermal conductivity in suspended few-layer h-BN. PMID:27142571

  11. Directional Movement of Droplets in Grooves: Suspended or Immersed?

    PubMed Central

    Xu, Wei; Lan, Zhong; Peng, Benli; Wen, Rongfu; Chen, Yansong; Ma, Xuehu

    2016-01-01

    The behavior of droplets trapped in geometric structures is essential to droplet manipulation applications such as for droplet transport. Here we show that directional droplet movement can be realized by a V-shaped groove with the movement direction controlled by adjusting the surface wettability of the groove inner wall and the cross sectional angle of the groove. Experiments and analyses show that a droplet in a superhydrophobic groove translates from the immersed state to the suspended state as the cross sectional angle of the groove decreases and the suspended droplet departs from the groove bottom as the droplet volume increases. We also demonstrate that this simple grooved structure can be used to separate a water-oil mixture and generate droplets with the desired sizes. The structural effect actuated droplet movements provide a controllable droplet transport method which can be used in a wide range of droplet manipulation applications. PMID:26743167

  12. Field investigation of suspended-sediment clouds under plunging breakers

    NASA Astrophysics Data System (ADS)

    Galloway, J. S.

    1988-08-01

    Breaking waves nearshore force the suspension of beach material and so play an important role in surf-zone sedimentological regimes. The analysis of cinemato-graphical records of wave breaking and bottom-sediment response for eight plunging and eight plunging-transition breakers has enabled the study of sand-cloud initiation, evolution and decay. The characteristics of the suspended-sediment clouds can be explained in terms of breaker energy dissipation. Some of the sand-cloud features are common to both plunging and plunging-transition breakers, although the total spatial and temporal history of the cloud is controlled by the water-surface profile evolution during breaking. Observations of breaker kinematics in the aerated region after breaking highlight the importance of breaker-induced vortices in controlling the initiation, concentration, elevation and longevity of suspended material in the surf zone.

  13. Directional Movement of Droplets in Grooves: Suspended or Immersed?

    NASA Astrophysics Data System (ADS)

    Xu, Wei; Lan, Zhong; Peng, Benli; Wen, Rongfu; Chen, Yansong; Ma, Xuehu

    2016-01-01

    The behavior of droplets trapped in geometric structures is essential to droplet manipulation applications such as for droplet transport. Here we show that directional droplet movement can be realized by a V-shaped groove with the movement direction controlled by adjusting the surface wettability of the groove inner wall and the cross sectional angle of the groove. Experiments and analyses show that a droplet in a superhydrophobic groove translates from the immersed state to the suspended state as the cross sectional angle of the groove decreases and the suspended droplet departs from the groove bottom as the droplet volume increases. We also demonstrate that this simple grooved structure can be used to separate a water-oil mixture and generate droplets with the desired sizes. The structural effect actuated droplet movements provide a controllable droplet transport method which can be used in a wide range of droplet manipulation applications.

  14. Ultra low 1/f noise in suspended bilayer graphene

    NASA Astrophysics Data System (ADS)

    Kumar, Manohar; Laitinen, Antti; Cox, Daniel; Hakonen, Pertti J.

    2015-06-01

    We have studied 1/f noise power SI in suspended bilayer graphene devices. Around the Dirac point, we observe ultra low noise amplitude on the order of f *SI/Ib2=10-9 . The low frequency noise level is barely sensitive to intrinsic carrier density, but temperature and external doping are found to influence the noise power. In our current-annealed samples, the 1/f noise is dominated by resistance fluctuations at the contacts. Temperature dependence of the 1/f noise suggests the presence of trap states in the contact regions, with a nearly exponential distribution function displaying a characteristic energy of 0.12 eV. At 80 K, the noise displays an air pressure sensitivity that corresponds to ˜0.3 ppm gas detection sensitivity; this indicates the potential of suspended graphene as a platform for gas sensing applications.

  15. Fast and controllable fabrication of suspended graphene nanopore devices

    NASA Astrophysics Data System (ADS)

    Liu, Song; Zhao, Qing; Xu, Jun; Yan, Kai; Peng, Hailin; Yang, Fuhua; You, Liping; Yu, Dapeng

    2012-03-01

    A poly(methyl methacrylate) assisted dry transfer method was developed to transfer graphene microflake onto a suspended SiN chip in an effective and efficient way for further graphene nanopore drilling for DNA analysis. Graphene microflakes can be patterned by e-beam lithography to a designed shape and size on a large scale of a few thousands simultaneously. Subsequently, individual graphene microflakes can be picked up and transferred to a target hole on a suspended SiN membrane with 1 µm precision via a site-specific transfer-printing method. Nanopores with different diameters from 3 to 20 nm were drilled on the as-transferred graphene membrane in a transmission electron microscope. This method offers a fast and controllable way to fabricate graphene nanopores for DNA analyses.

  16. Prototype of a magnetically suspended flywheel energy storage system

    NASA Technical Reports Server (NTRS)

    Plant, David P.; Kirk, J. A.; Anand, D. K.

    1989-01-01

    The authors describe recent progress in the development of a 500-Wh magnetically suspended flywheel stack energy storage system. The design of the system and a critical study of the noncontacting displacement transducers and their placement in the stack system are discussed. The storage system has been designed and constructed and is currently undergoing experimental analysis. The results acquired from the noncontacting displacement transducer study show that currently available transducers will not function as desired and that further research is essential.

  17. Technological advances in suspended-sediment surrogate monitoring

    NASA Astrophysics Data System (ADS)

    Gray, John R.; Gartner, Jeffrey W.

    2009-04-01

    Surrogate technologies to continuously monitor suspended sediment show promise toward supplanting traditional data collection methods requiring routine collection and analysis of water samples. Commercially available instruments operating on bulk optic (turbidity), laser optic, pressure difference, and acoustic backscatter principles are evaluated based on cost, reliability, robustness, accuracy, sample volume, susceptibility to biological fouling, and suitable range of mass concentration and particle size distribution. In situ turbidimeters are widely used. They provide reliable data where the point measurements can be reliably correlated to the river's mean cross section concentration value, effects of biological fouling can be minimized, and concentrations remain below the sensor's upper measurement limit. In situ laser diffraction instruments have similar limitations and can cost 6 times the approximate $5000 purchase price of a turbidimeter. However, laser diffraction instruments provide volumetric-concentration data in 32 size classes. Pressure differential instruments measure mass density in a water column, thus integrating substantially more streamflow than a point measurement. They are designed for monitoring medium-to-large concentrations, are generally unaffected by biological fouling, and cost about the same as a turbidimeter. However, their performance has been marginal in field applications. Acoustic Doppler profilers use acoustic backscatter to measure suspended sediment concentrations in orders of magnitude more streamflow than do instruments that rely on point measurements. The technology is relatively robust and generally immune to effects of biological fouling. Cost of a single-frequency device is about double that of a turbidimeter. Multifrequency arrays also provide the potential to resolve concentrations by clay silt versus sand size fractions. Multifrequency hydroacoustics shows the most promise for revolutionizing collection of continuous

  18. Comparison of suspended and fixed photocatalytic reactor systems.

    PubMed

    Geissen, S U; Xi, W; Weidemeyer, A; Vogelpohl, A; Bousselmi, L; Ghrab, A; Nnabi, A E

    2001-01-01

    Photocatalysis is a promising technology for the purification of pretreated wastewaters in sun-rich countries if an economically applicable reactor system is available. Within this project the catalyst separation as an essential process step of suspended reactor systems was investigated. For the separation of suspended catalyst a sedimentation basin with and without lamella and a membrane filtration were investigated. The sedimentation was found to be very sensitive to the kind of the ion background of wastewater, the pH, the TiO2 influent concentration as well as the hydrodynamics in the clarifier. Under optimized conditions effluent concentrations of less than 5 mg SS/L and a clear water without turbidity could be reached with a specific flow rate of up to 0.7 m3/m2/h. The best performance for P25 was achieved with a TiO2 influent concentration of 5 g/L. Membrane filtration was the only method to guarantee a complete retention of the TiO2 as well as a rejection of microorganisms and high molecular compounds. With cross-flow velocities of 3 m/s and a transmembrane pressure of 100 kPa flux rates up to 1,200 L/m2/h were achieved. A flow-film-reactor (FFR) was operated with the model compound DCA under identical conditions with fixed and suspended TiO2. Whereas the fixed system has the advantage that no separation step is necessary and a simple construction can be used, suspended systems offer a three times higher reaction velocity for a catalyst concentration of 10 g/L, but are also characterized by higher investment costs.

  19. Technological advances in suspended-sediment surrogate monitoring

    USGS Publications Warehouse

    Gray, John R.; Gartner, Jeffrey W.

    2009-01-01

    Surrogate technologies to continuously monitor suspended sediment show promise toward supplanting traditional data collection methods requiring routine collection and analysis of water samples. Commercially available instruments operating on bulk optic (turbidity), laser optic, pressure difference, and acoustic backscatter principles are evaluated based on cost, reliability, robustness, accuracy, sample volume, susceptibility to biological fouling, and suitable range of mass concentration and particle size distribution. In situ turbidimeters are widely used. They provide reliable data where the point measurements can be reliably correlated to the river's mean cross section concentration value, effects of biological fouling can be minimized, and concentrations remain below the sensor's upper measurement limit. In situ laser diffraction instruments have similar limitations and can cost 6 times the approximate $5000 purchase price of a turbidimeter. However, laser diffraction instruments provide volumetric-concentration data in 32 size classes. Pressure differential instruments measure mass density in a water column, thus integrating substantially more streamflow than a point measurement. They are designed for monitoring medium-to-large concentrations, are generally unaffected by biological fouling, and cost about the same as a turbidimeter. However, their performance has been marginal in field applications. Acoustic Doppler profilers use acoustic backscatter to measure suspended sediment concentrations in orders of magnitude more streamflow than do instruments that rely on point measurements. The technology is relatively robust and generally immune to effects of biological fouling. Cost of a single-frequency device is about double that of a turbidimeter. Multifrequency arrays also provide the potential to resolve concentrations by clay silt versus sand size fractions. Multifrequency hydroacoustics shows the most promise for revolutionizing collection of continuous

  20. [Light absorption by suspended particulate matter in Chagan Lake, Jilin].

    PubMed

    Wang, Yuan-Dong; Liu, Dian-Wei; Song, Kai-Shan; Zhang, Bai; Wang, Zong-Ming; Jiang, Guang-Ji; Tang, Xu-Guang; Lei, Xiao-Chun; Wu, Yan-Qing

    2011-01-01

    Spectral characteristics and the magnitudes of light absorption by suspended particulate matter were determined by spectrophotometry in this optically complex Lake Chagan waters for the purpose of surveying the natural variability of the absorption coefficients to parameterize the bio-optical models for converting satellite or in-situ water reflectance signatures into water quality information. Experiments were carried out on seasonal frozen Lake Chagan, one representative inland case-2 water body in Northeast of China. Particulate absorption properties analyzed using the field data on July 15th and October 12th 2009 were measured using the quantitative filter technique to produce absorption spectra containing several fractions that could be attributed to two main optical active constituents (OACs) phytoplankton pigments and non-algal particulates (mineral sediments, and organic detritus). Results suggested that the suspended particulate matter (SPM) concentration was higher while phytoplankton biomass (chlorophyll-a concentration) was lower in July and that in October. The spectral shape of total suspended particulate matter resembled that of non-algal particulates which contributed greater than phytoplankton in total particulate absorption during both periods. An obvious absorption peak occurring at around 440 nm exhibited an increase in phytoplankton contribution in October. Non-algal particulate absorption at 440 nm (a(NAP) (440)) had better correlation with total suspended particulate matter concentration than that with chlorophyll-a over the two periods. Light absorption by phytoplankton pigments in the Chagan lake region was generally lower than that of non-algal components. Chl. a dominating phytoplankton pigment composition functioned exponentially with its absorption coefficients at 440 and 675 nm specifically, the average values of which in July were 0.146 8 m2 x mg(-1) and 0.050 3 respectively while in October they were 0.153 3 and 0.013 2 m2 x mg(-1

  1. A space test plan of a magnetically suspended flywheel

    NASA Astrophysics Data System (ADS)

    Murakami, C.; Nakajima, A.; Oguchi, M.; Toda, S.; Kibe, S.

    The mounting and testing of a magnetically suspended flywheel on the H-I rocket developed by NASDA are discussed. The main experimental items are: (1) testing of the launch lock system of the rotor part of the flywheel; (2) identification of the oscillatory characteristics of the magnetic bearing under zero g condition. The experimental apparatus consists of magnetic bearing flywheel, TT&C(VHF), and attitude monitors and power source sections.

  2. Suspended sediment transport in an ephemeral stream following wildfire

    USGS Publications Warehouse

    Malmon, D.V.; Reneau, S.L.; Katzman, D.; Lavine, A.; Lyman, J.

    2007-01-01

    We examine the impacts of a stand-clearing wildfire on the characteristics and magnitude of suspended sediment transport in ephemeral streams draining the burn area. We report the results of a monitoring program that includes 2 years of data prior to the Cerro Grande fire in New Mexico, and 3 years of postfire data. Suspended sediment concentration (SSC) increased by about 2 orders of magnitude following the fire, and the proportion of silt and clay increased from 50% to 80%. For a given flow event, SSC is highest at the flood bore and decreases monotonically with time, a pattern evident in every flood sampled both before and after the fire. We propose that the accumulation of flow and wash load at the flow front is an inherent characteristic of ephemeral stream flows, due to amplified momentum losses at the flood bore. We present a new model for computing suspended sediment transport in ephemeral streams (in the presence or absence of wildfire) by relating SSC to the time following the arrival of the flood bore, rather than to instantaneous discharge. Using this model and a rainfall history, we estimate that in the 3 years following the fire, floods transported in suspension a mass equivalent to about 3 mm of landscape lowering across the burn area, 20% of this following a single rainstorm. We test the model by computing fine sediment delivery to a small reservoir in an adjacent watershed, where we have a detailed record of postfire sedimentation based on repeat surveys. Systematic discrepancies between modeled and measured sedimentation rates in the reservoir suggest rapid reductions in suspended sediment delivery in the first several years after the fire.

  3. Suspended core photonic microcells for sensing and device applications.

    PubMed

    Wang, Chao; Jin, Wei; Ma, Jun; Wang, Ying; Ho, Hoi Lut; Shi, Xin

    2013-06-01

    In-line fiber-optic microcells are fabricated by postprocessing NKT LMA10 photonic crystal fibers. The cells are suspended core (SC) elements created by locally inflating some of the air holes while the core is being tapered. Based on a SC microcell with six air holes, a cantilever beam accelerometer is demonstrated. The microcells could also be used as gain and absorption cells for amplifier and spectroscopy applications. PMID:23722776

  4. Pseudomagnetic fields and ballistic transport in a suspended graphene sheet.

    PubMed

    Fogler, M M; Guinea, F; Katsnelson, M I

    2008-11-28

    We study a suspended graphene sheet subject to the electric field of a gate underneath. We compute the elastic deformation of the sheet and the corresponding effective gauge field, which modifies the electronic transport. In a clean system the two-terminal conductance of the sample is reduced below the ballistic limit and is almost totally suppressed at low carrier concentrations in samples under tension. Residual disorder restores a small finite conductivity. PMID:19113505

  5. Study of extended life coolant with suspended carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Overturf, Logan

    Utilizing an experimental facility which was prepared to conduct performance tests on heat exchangers; experiments were completed in an attempt to see verifiable improvements in overall heat transfer coefficient in engine coolant with nanoparticles suspended at different weight percentages. The different fluids tested were: base ELC (Extended Life Coolant), ELC with 0.002 wt% CNT (Carbon Nanotubes), ELC with 0.02 wt% CNT, ELC with 0.02 wt% MWNT's (Multiwalled Nanotubes) and water. The volume percents range from 0.00164 volume% to 0.0164 volume% which seemed quite small, but according to Caterpillar representatives, were the best concentration. These fluids were tested at standard flowrates which this type of heat exchanger would be used in as well as a higher air flowrate and lower coolant flowrates in an attempt to gather more verifiable data. Results were obtained regarding the change in heat transfer ability of engine coolant with suspended nanoparticles. For this system under these specific conditions, there was verifiably no increase in UA as nanoparticles were added to the coolant. The benefits of adding nanoparticles to engine coolant have potential to be great, but the cost of nanoparticles and difficulty keeping them suspended may outweigh any benefits obtainable in this type of set up.

  6. Suspended single-walled carbon nanotube fluidic sensors.

    PubMed

    Son, B H; Park, Ji-Yong; Lee, Soonil; Ahn, Y H

    2015-10-01

    In this paper, we demonstrate the fabrication of liquid flow sensors employing partially suspended single-walled carbon nanotubes (SWNTs). We have found that the sign of the conductance change in SWNT flow sensors is not influenced by the direction of water flow for both supported and suspended devices. Therefore, the streaming potential is not the principal mechanism of the SWNT sensor response. Instead, the conductance change is more likely due to a reduction in the cation density in the electrical double layer, whose equilibrium conditions are determined by the liquid flow rate. More importantly, we have found that the sensitivity of suspended SWNT devices is more than 10 times greater than that of supported SWNT devices. A reduced screening effect and an increase in effective sensing volume are responsible for the enhanced sensitivity, which is consistent with the ion depletion model. We also have measured conductance as a function of gate bias at different flow rates and have determined the flow-rate dependent effective charge density, which influences the electrostatic configuration around SWNT devices.

  7. Raman spectroscopy of suspended mono and bilayer graphene

    NASA Astrophysics Data System (ADS)

    Kitt, Alexander; Feldman, Benjamin; Remi, Sebastian; Martin, Jens; Swan, Anna; Yacoby, Amir; Goldberg, Bennett

    2010-03-01

    Suspended mono and bilayer graphene flakes have been shown to have higher mobility and lower disorder than their supported counterparts^1. The geometry which decouples the flake from the substrate also causes an as yet uncharacterized backgate specific strain due to an electrostatic attraction between the graphene and the back gated substrate. We study this strain using spatially resolved Raman spectroscopy with a diffraction limited spot size. Upon application of uni-axial strain the unit cell is stretched reducing the symmetry of the system and breaking the double degeneracy of the G band causing a split in the peak. Additionally the Raman modes show a linear softening as a function of strain in the case of supported graphene. Suspended flakes provide an ideal system to study back gate tunable strain while avoiding complications due to substrates including the determination of the Poisson ratio and sample slippage^2. Here we present preliminary results of our observations. 1: B Feldman, J Martin, A Yacoby, ``Broken-symmetry states and divergent resistance in suspended bilayer graphene'', Nature Physics, doi:10.1038/nphys1406 2: C Metzger et al, ``Biaxial strain in graphene adhered to shallow depressions'', Accepted for publication in Nano Letters

  8. Longitudinal dispersion in open channel flow with suspended canopies.

    PubMed

    Huai, Wenxin; Li, Chengguang

    2016-01-01

    Suspended canopies can cause flow disturbances such as reducing velocities within the canopy, and increasing flow beneath the canopy. Flow modifications by canopies dramatically affect the fate and transport of sediment, nutrients, contaminants, dissolved oxygen, and fauna in aquatic systems. A three-zone model is presented here to predict the longitudinal dispersion coefficient by simplifying Chikwendu's N-zone model. To validate the model, both flow field and tracer experiments were conducted using a straight rectangular Plexiglas flume, with rigid circular rods as the modeled suspended canopies. The result shows that velocities increased above the flume bed and maximized at a point between the canopies and flume bed. Above that point, streamwise velocities decreased into and within the canopies. Reynolds shear stresses were largest at the canopy interface and smallest (zero) at the velocity maximum point. Good agreement between the modeled results and experimental data shows that the model can effectively predict the longitudinal dispersion coefficient in open channels with suspended canopies. PMID:27508377

  9. Growth of protein crystals suspended in a closed loop thermosyphon

    NASA Astrophysics Data System (ADS)

    Nyce, Thomas A.; Rosenberger, Franz

    1991-03-01

    The quality of protein crystals often suffers from their growth at a liquid or solid surface. A novel solution growth method was developed to alleviate this problem. A growing crystal is suspended in a specially configured upflow of supersaturated nutrient, which is provided by the effect of fluid buoyancy in a closed loop thermosyphon. The flow rate and supersaturation are controlled by the temperature distribution in the thermosyphon, while contact of the crystal with the wall during growth is practically eliminated. The method was applied to the growth of lysozyme single crystals, with surprising results. While the orthorhombic form of lysozyme grew readily to the suspension limit of this particular apparatus (1.5 mm), the tetragonal form grew only to a maximum size less than 0.1 mm. Seed crystals of tetragonal lysozyme introduced into stagnant batch controls did not experience the growth cessation that the suspended crystals did. A likely cause of this growth cessation is the fluid shear forces on the suspended crystals.

  10. Method of making suspended thin-film semiconductor piezoelectric devices

    DOEpatents

    Casalnuovo, Stephen A.; Frye-Mason, Gregory C.

    2001-01-01

    A process for forming a very thin suspended layer of piezoelectric material of thickness less than 10 microns. The device is made from a combination of GaAs and AlGaAs layers to form either a sensor or an electronic filter. Onto a GaAs substrate is epitaxially deposited a thin (1-5 micron) sacrificial AlGaAs layer, followed by a thin GaAs top layer. In one embodiment the substrate is selectively etched away from below until the AlGaAs layer is reached. Then a second selective etch removes the sacrificial AlGaAs layer, that has acted here as an etch stop, leaving the thin suspended layer of piezoelectric GaAs. In another embodiment, a pattern of small openings is etched through the thin layer of GaAs on top of the device to expose the sacrificial AlGaAs layer. A second selective etch is done through these openings to remove the sacrificial AlGaAs layer, leaving the top GaAs layer suspended over the GaAs substrate. A novel etchant solution containing a surface tension reducing agent is utilized to remove the AlGaAs while preventing buildup of gas bubbles that would otherwise break the thin GaAs layer.

  11. Estimation of local extreme suspended sediment concentrations in California Rivers.

    PubMed

    Tramblay, Yves; Saint-Hilaire, André; Ouarda, Taha B M J; Moatar, Florentina; Hecht, Barry

    2010-09-01

    The total amount of suspended sediment load carried by a stream during a year is usually transported during one or several extreme events related to high river flow and intense rainfall, leading to very high suspended sediment concentrations (SSCs). In this study quantiles of SSC derived from annual maximums and the 99th percentile of SSC series are considered to be estimated locally in a site-specific approach using regional information. Analyses of relationships between physiographic characteristics and the selected indicators were undertaken using the localities of 5-km radius draining of each sampling site. Multiple regression models were built to test the regional estimation for these indicators of suspended sediment transport. To assess the accuracy of the estimates, a Jack-Knife re-sampling procedure was used to compute the relative bias and root mean square error of the models. Results show that for the 19 stations considered in California, the extreme SSCs can be estimated with 40-60% uncertainty, depending on the presence of flow regulation in the basin. This modelling approach is likely to prove functional in other Mediterranean climate watersheds since they appear useful in California, where geologic, climatic, physiographic, and land-use conditions are highly variable. PMID:20570317

  12. Performance comparison of suspended bed and batch contactor chromatography.

    PubMed

    Quiñones-García, I; Rayner, I; Levison, P R; Dickson, N; Purdom, G

    2001-01-26

    In some applications, the purification and recovery of biomolecules is performed via a cascade of batch adsorption and desorption stages using agitated contactors and related filtration devices. Suspended bed chromatography is a recent process-scale innovation that is applicable to these separations. This hybrid technique exploits the benefits of combining batch adsorption in an agitated contactor with elution in an enclosed column system. To some extent, the process is similar to batch contactor chromatography but can be fully contained and significantly quicker. The process has two steps; first the fluid containing the sample is mixed with the adsorbent in a stirred tank. Second, the slurry suspension is transferred directly into a specialized column, such as an IsoPak column. The media with the adsorbed product is formed as a packed bed, whilst the suspension liquid is passed out of the column. The product is then eluted from the packed bed utilizing standard column-chromatography techniques. The performance of the suspended bed and the agitated contactor operations are demonstrated both by full-scale experimental results and process simulations. The purification of ovalbumin from a hen-egg white feedstock by anion-exchange chromatography was used as a case study in order to prove the concept. With the availability of both pump-packed systems and shear-resistant media, suspended bed chromatography is a better alternative for a range of applications than the traditional batch separations using agitated contactors. PMID:11218119

  13. Suspended Particles: Their Role in Estuarine Biogeochemical Cycles

    NASA Astrophysics Data System (ADS)

    Turner, A.; Millward, G. E.

    2002-12-01

    Suspended particles are instrumental in controlling the reactivity, transport and biological impacts of substances in aquatic environments, and provide a crucial link for chemical constituents between the water column, bed sediment and food chain. This article reviews the role of suspended particles in the chemical and biological cycling of trace constituents (trace metals, organo-metallic compounds and hydrophobic organic micropollutants; HOMs) in estuaries, with particular emphasis on the effects of and changes to particle reactivity and composition. The partitioning (or distribution coefficient, KD ) and bioavailability of chemical constituents, and assimilation efficiency (AE) of such by bivalve suspension feeders, are identified as key parameters requiring definition for accurate biogeochemical modelling, and the discussion centres around the determination of and controls on these parameters. Particle-water interactions encompass a variety of physical, biological, electrostatic and hydrophobic effects, and are largely dependent on the character and concentration of suspended particles and salinity. The salinity-dependence results from the competing and complexing effects of seawater ions for trace metals, and the compression of water in the presence of dissolved seawater ions and consequent salting out of neutral solute (HOMs, organo-metallic compounds and some trace metal complexes). The extent of biological solubilization of chemical constituents from suspended particles is dependent on the nature of chemical components of the gastro-intestinal environment and their interactions with ingested particles, and the physiological (e.g. gut passage time) and chemical (e.g. redox conditions and pH) constraints imposed on these interactions. Generally, chemicals that associate with fine, organic-rich particles (or, for some HOMs, fine inorganic particles), and desorb at pH 5-6 and/or complex with digestive enzymes or surfactants are most readily solubilized in the

  14. Estimation of suspended-sediment concentration from total suspended solids and turbidity data for Kentucky, 1978-1995

    USGS Publications Warehouse

    Williamson, Tanja N.; Crawford, Charles G.

    2011-01-01

    Suspended sediment is a constituent of water quality that is monitored because of concerns about accelerated erosion, nonpoint contamination of water resources, and degradation of aquatic environments. In order to quantify the relationship among different sediment parameters for Kentucky streams, long-term records were obtained from the National Water Information System of the U.S. Geological Survey. Suspended-sediment concentration (SSC), the parameter traditionally measured and reported by the U.S. Geological Survey, was statistically compared to turbidity and total suspended solids (TSS), two parameters that are considered surrogate data. A linear regression of log-transformed observations was used to estimate SSC from TSS; 72% of TSS observations were less than coincident SSC observations; however, the estimated SSC values were almost as likely to be overestimated as underestimated. The SSC-turbidity relationship also used log-transformed observations, but required a nonlinear, breakpoint regression that separated turbidity observations ???6nephelometric turbidity units. The slope for these low turbidity values was not significantly different than zero, indicating that low turbidity observations provide no real information about SSC; in the case of the Kentucky sediment record, this accounts for 30% of the turbidity observations. ?? 2011 American Water Resources Association. This article is a U.S. Government work and is in the public domain in the USA.

  15. A New Simple Suspended-Load Sampler: Continuous Particulate Matter Collection from Rivers with Low and High Suspended Matter Load

    NASA Astrophysics Data System (ADS)

    Kralik, Martin; Miesbauer, Hermann; Humer, Franko; Oberndorfer, Hermann

    2010-05-01

    Please fill in your abstract text. Suspended particulate matter (SPM) or suspended load in waters is the part of the stream load that is carried for a considerable period of time in suspension. Long term suspended sediment monitoring is hampered by the limited sample size or enormous investments in equipment and/or working hours. In addition many samplers are limited to easily accessible sampling points equipped with electric power supply or to certain types of streams and cannot operate unattended in case of floods. The sorption characteristics of the suspended particulate matter (wash load) have been recognized as important transporters of natural and anthropogenic trace constituents. To allow repeated analyses sometimes several grams of dried SPM are needed. All parts of the sediment sampler are available as spare parts in hardware stores and made of polyvinylchloride (PVC). The inlet device is connected with the sampler by a tubing of several meter length. Without a pump the sampler can be positioned at a safe place lower than the inlet device to allow a continuous flow. Only a small portion (0.001-0.002 l/s) of the river water flows down through the central pipe by gravitational force to the bottom of the container. Due to the considerable larger diameter of the container the water rises very slowly (1-3 hours) and leaves the container at a small overflow-pipe allowing a nearly complete settling and/or flocculation (80-90%) of the suspended load in the container. The sampler was tested in an alpine torrent and two rivers in flat areas. The newly developed sampler offers following advantages. The sampler (1) is inexpensive and robust, (2) operates in case of small cascade or cataracts (>0.5 m) without power supply, (3) can be used singly or in lateral or vertical nests, (4) allows continuous settling and flocculation without perturbation by vibrating movements of the sampler (5) is resistant to plugging and clogging by coarser particles and plant debris, (6

  16. Suspended Alexandrium spp. hypnozygote cysts in the Gulf of Maine

    NASA Astrophysics Data System (ADS)

    Kirn, Sarah L.; Townsend, David W.; Pettigrew, Neal R.

    2005-09-01

    The life cycle of dinoflagellates of the genus Alexandrium includes sexual reproduction followed by the formation of a dormant hypnozygote cyst, which serves as a resting stage. Negatively buoyant cysts purportedly fall to the benthos where they undergo a mandatory period of quiescence. Previous reports of cysts in the surficial sediments of the Gulf of Maine, where Alexandrium blooms are well documented, show a broad distribution of cysts, with highest concentrations generally in sediments below 100 m depth. We report here an exploration of cysts suspended in the water column, where they would be better positioned to inoculate springtime Alexandrium populations. During cruises in February, April, and June of 2000, water samples were collected at depths just off the bottom (within 5 m), at the top of the bottom nepheloid layer, and near the surface (1 m) and examined for cyst concentrations. Suspended cysts were found throughout the Gulf of Maine and westernmost Bay of Fundy. Planktonic cyst densities were generally greater in near-bottom and top of the bottom nepheloid layer samples than in near-surface water samples; densities were of the order of 10 2 cysts m -3 in surface waters, and 10 2-10 3 cysts m -3 at near-bottom depths. Temporally, they were most abundant in February and least abundant in April. Reports by earlier workers of cysts in the underlying sediments were on the order of 10 3 cysts cm -3. We present calculations that demonstrate the likelihood of cyst resuspension from bottom sediments forced by swell and tidal currents, and propose that such resuspended cysts are important in inoculating the seasonal bloom. We estimate that suspended cysts may contribute significantly to the annual vegetative cell population in the Gulf of Maine.

  17. Super-bridges suspended over carbon nanotube cables

    NASA Astrophysics Data System (ADS)

    Carpinteri, Alberto; Pugno, Nicola M.

    2008-11-01

    In this paper the new concept of 'super-bridges', i.e. kilometre-long bridges suspended over carbon nanotube cables, is introduced. The analysis shows that the use of realistic (thus defective) carbon nanotube bundles as suspension cables can enlarge the current limit main span by a factor of ~3. Too large compliance and dynamic self-excited resonances could be avoided by additional strands, rendering the super-bridge anchored as a spider's cobweb. As an example, we have computed the limit main spans of the current existing 19 suspended-deck bridges longer than 1 km assuming them to have substituted their cables with carbon nanotube bundles (thus maintaining the same geometry, with the exception of the length) finding spans of up to ~6.3 km. We thus suggest that the design of the Messina bridge in Italy, which would require a main span of ~3.3 km, could benefit from the use of carbon nanotube bundles. We believe that their use represents a feasible and economically convenient solution. The plausibility of these affirmations is confirmed by a statistical analysis of the existing 100 longest suspended bridges, which follow a Zipf's law with an exponent of 1.1615: we have found a Moore-like (i.e. exponential) law, in which the doubling of the capacity (here the main span) per year is substituted by the factor 1.0138. Such a law predicts that the realization of the Messina bridge using conventional materials will only occur around the middle of the present century, whereas it could be expected in the near future if carbon nanotube bundles were used. A simple cost analysis concludes the paper.

  18. Photoacoustic response of suspended and hemolyzed red blood cells

    NASA Astrophysics Data System (ADS)

    Saha, Ratan K.; Karmakar, Subhajit; Roy, Madhusudan

    2013-07-01

    The effect of confinement of hemoglobin molecules on photoacoustic (PA) signal is studied experimentally. The PA amplitudes for samples with suspended red blood cells (SRBCs) and hemolyzed red blood cells (HRBCs) were found to be comparable at each hematocrit for 532 nm illumination. The difference between the corresponding amplitudes increased with increasing hematocrit for 1064 nm irradiation. For example, the PA amplitude for the SRBCs was about 260% higher than that of the HRBCs at 40% hematocrit. This observation may help to develop a PA method detecting hemolysis noninvasively.

  19. Correlation study between suspended particulate matter and DOAS data

    NASA Astrophysics Data System (ADS)

    Si, Fuqi; Liu, Jianguo; Xie, Pinghua; Zhang, Yujun; Liu, Wenqing; Kuze, Hiroaki; Lagrosas, Nofel; Takeuchi, Nobuo

    2006-05-01

    Continuous data of aerosol optical thickness monitored using differential optical absorption spectroscopy (DOAS) are correlated with the concentration of ground-measured suspended particulate matter (SPM). A high correlation is found between the DOAS and the ground SPM data, making it possible to calculate the mass extinction efficiency of the aerosols in the atmosphere. It is found that the value of mean mass extinction efficiency (MEE) varies over a range of 2.6 13.7 m2 g-1, with smaller and larger values occurring for size distributions dominated by coarse and fine particles, respectively.

  20. Suspended sediment control and water quality conservation through riparian vegetation:

    NASA Astrophysics Data System (ADS)

    Pavanelli, D.; Cavazza, C.; Correggiari, S.

    2009-04-01

    Soil erosion and Suspended Sediment River are strongly related in the Apennines catchments which are generally characterised by a clayey lithology and impermeable soils and extensive and severe erosion and slope stability problems. In fact the suspended sediment yield represents one of the most reliable tools to assess real basin soil loss (Pavanelli and Pagliarani, 2002; Pavanelli and Rigotti, 2007) from the surface rain erosive features in a mountain watershed, as rills and interrills erosion, gullies, bad-lands (calanchi basins). Suspended sediment yield is known to imply several detrimental consequences: soil losses from agricultural land, worsening of the quality of the water, clogging of water supply filters and reservoir siltation. In addition, suspended sediment yield is also one of the main vector for pollutants and nutrients: various studies have already proved how nitrogen content has been constantly rising in aquifers and surface waters [Böhlke and Denver, 1995]. Finer particles and their aggregates have been proved to be the preferential vehicle for particulate nitrogen [Droppo et al., 1997; Ongley et al., 1992]. In one research [Pavanelli and al. 2006] four Apennines torrents (Gaiana, Sillaro, Savena and Lavino) with mountain basins ranging from 8.7 to 139 Km2 were monitored via automatic sampling devices, the samples of water collected were analysed to characterise suspended solids in terms of their grain size distribution and total nitrogen with respect to the source of eroded area in the catchment. Preliminary results [Pavanelli and al. 2007] seem to show the existence of a direct relationship between nitrogen concentration and finer particle concentration (<20 μm), with the maximum nitrogen loss values being related to factors like the presence of clayey formations, their position within the catchment and the availability of suspended particles. The results seem to indicate hillsides as main sources of suspended sediment to the torrents

  1. Heat transfer of suspended carbon nanotube yarn to gases

    NASA Astrophysics Data System (ADS)

    Wada, Yukiko; Kita, Koji; Takei, Kuniharu; Arie, Takayuki; Akita, Seiji

    2016-08-01

    We investigate the pressure dependence of heat transfer to ambient gases for a suspended carbon nanotube yarn. The heat transport of the yarn including the heat exchange with surrounding gases is investigated using a simple one-dimensional heat transport model under Joule heating of the yarn. It is revealed that the effective diameter of the yarn for heat exchange is much smaller than the geometrical diameter of the yarn. This smaller effective diameter for heat exchange should contribute to realizing higher sensitivity and sensing over a wider range of pressures for heat-exchange-type vacuum gauges and flow sensors.

  2. LAGRANGIAN MODELING OF A SUSPENDED-SEDIMENT PULSE.

    USGS Publications Warehouse

    Schoellhamer, David H.

    1987-01-01

    The one-dimensional Lagrangian Transport Model (LTM) has been applied in a quasi two-dimensional manner to simulate the transport of a slug injection of microbeads in steady experimental flows. A stationary bed segment was positioned below each parcel location to simulate temporary storage of beads on the bottom of the flume. Only one degree of freedom was available for all three bead simulations. The results show the versatility of the LTM and the ability of the LTM to accurately simulate transport of fine suspended sediment.

  3. Activated Sludge and other Aerobic Suspended Culture Processes.

    PubMed

    Li, Chunying; Wei, Li; Chang, Chein-Chi; Zhang, Yuhua; Wei, Dong

    2016-10-01

    This is a literature review for the year 2015 and contains information specifically associated with suspended growth processes including activated sludge, upflow anaerobic sludge blanket, and sequencing batch reactors. The review encompasses modeling and kinetics, nutrient removal, system design and operation. Compared to past reviews, many topics show increase in activity in 2015. These include, fate and effect of xenobiotics, industrial wastes treatment with sludge, and pretreatment for the activated sludge. These topics are referred to the degradation of constituents in activated sludge. Other sections include population dynamics, process microbiology give an insight into the activated sludge. The subsection in industrial wastes: converting sewage sludge into biogases was also mentioned.

  4. Suspended sediment load, climate and relief in the central Pamirs

    NASA Astrophysics Data System (ADS)

    Pohl, Eric; Gloaguen, Richard; Andermann, Christoff; Schön, Ariane

    2013-04-01

    Relief and climate affect the generation of sediment transport. While relief and climate also affect each other, their influence on sediment transport can be investigated separately to determine their direct impact on this matter. Taking into account the complex topography of the central Pamirs and the fact that this region marks the transition zone of the Westerlies and the northward Indian Summer Monsoon, this region provides an excellent basis to investigate the interrelationship between sediment transport, climate and relief. The Panj River and its tributaries are representative for the hydrological setting of the central Pamirs as they drain most of the region. We first present suspended sediment characteristics from historical archive data for the whole river catchment and for the sub-catchments. We show the dynamics of the relationship between suspended sediment concentration and discharge on an annual basis for the different catchment sizes. The uppermost catchments are characterized by a transport-limited situation, showing a simple power-law relationship between discharge and sediment concentration for the entire year. The lowermost catchments show a strong hysteresis effect, especially in spring, which is related to the onset of snowmelt. The result is a differentiated power-law relationship within a year. As snow and glacier melt control the discharge in the central Pamirs, we investigate the climatological conditions derived from remote sensing data. We do this with respect to the different sub-catchments and with a special focus on the temporal variability. Results from the previous steps are finally interrelated with calculated geomorphological features at different catchment scales to characterize the suspended sediment load in the context of both relief and climatic conditions. Our results suggest climate to play the first-order determinant for the generation of suspended sediment load. This is in particular due to the Westerlies that provide the

  5. Activated Sludge and other Aerobic Suspended Culture Processes.

    PubMed

    Li, Chunying; Wei, Li; Chang, Chein-Chi; Zhang, Yuhua; Wei, Dong

    2016-10-01

    This is a literature review for the year 2015 and contains information specifically associated with suspended growth processes including activated sludge, upflow anaerobic sludge blanket, and sequencing batch reactors. The review encompasses modeling and kinetics, nutrient removal, system design and operation. Compared to past reviews, many topics show increase in activity in 2015. These include, fate and effect of xenobiotics, industrial wastes treatment with sludge, and pretreatment for the activated sludge. These topics are referred to the degradation of constituents in activated sludge. Other sections include population dynamics, process microbiology give an insight into the activated sludge. The subsection in industrial wastes: converting sewage sludge into biogases was also mentioned. PMID:27620082

  6. Regional volume changes in canine lungs suspended in air

    NASA Technical Reports Server (NTRS)

    Abbrecht, Peter H.; Kyle, Richard R.; Bryant, Howard J.; Feuerstein, Irwin

    1995-01-01

    The purpose of this study was to determine the effect of the absence of a pleural pressure gradient (simulating the presumed condition found in microgravity) upon regional expansion of the lung. We attempted to produce a uniform pressure over the surface of the lung by suspending excised lungs in air. Such studies should help determine whether or not the absence of a pleural pressure gradient leads to uniform ventilation. A preparation in which there is no pleural pressure gradient should also be useful in studying non-gravitational effects on ventilation distribution.

  7. Development of suspended normal-metal-type tunneling junction refrigerator

    NASA Astrophysics Data System (ADS)

    Kashiwaya, Satoshi; Kashiwaya, Hiromi; Koyanagi, Masao; Tanaka, Yukio

    2016-09-01

    We have developed a suspended normal-metal-type superconducting-normal metal-superconductor tunneling junction refrigerator for the cooling of highly sensitive sensors operating at ultralow temperatures. The performance of the refrigerator is evaluated by comparing the experimental conductance with the numerical results of a theoretical formulation. The lowest temperature of 0.093 K at a bath temperature of 0.334 K indicates the successful operation of the refrigerator. The maximum cooling power of the present refrigerator estimated on the basis of the nonequilibrium stationary state model is 213 pW for a junction area of 40 × 7 µm2.

  8. Suspended sediment control and water quality conservation through riparian vegetation:

    NASA Astrophysics Data System (ADS)

    Pavanelli, D.; Cavazza, C.; Correggiari, S.

    2009-04-01

    Soil erosion and Suspended Sediment River are strongly related in the Apennines catchments which are generally characterised by a clayey lithology and impermeable soils and extensive and severe erosion and slope stability problems. In fact the suspended sediment yield represents one of the most reliable tools to assess real basin soil loss (Pavanelli and Pagliarani, 2002; Pavanelli and Rigotti, 2007) from the surface rain erosive features in a mountain watershed, as rills and interrills erosion, gullies, bad-lands (calanchi basins). Suspended sediment yield is known to imply several detrimental consequences: soil losses from agricultural land, worsening of the quality of the water, clogging of water supply filters and reservoir siltation. In addition, suspended sediment yield is also one of the main vector for pollutants and nutrients: various studies have already proved how nitrogen content has been constantly rising in aquifers and surface waters [Böhlke and Denver, 1995]. Finer particles and their aggregates have been proved to be the preferential vehicle for particulate nitrogen [Droppo et al., 1997; Ongley et al., 1992]. In one research [Pavanelli and al. 2006] four Apennines torrents (Gaiana, Sillaro, Savena and Lavino) with mountain basins ranging from 8.7 to 139 Km2 were monitored via automatic sampling devices, the samples of water collected were analysed to characterise suspended solids in terms of their grain size distribution and total nitrogen with respect to the source of eroded area in the catchment. Preliminary results [Pavanelli and al. 2007] seem to show the existence of a direct relationship between nitrogen concentration and finer particle concentration (<20 μm), with the maximum nitrogen loss values being related to factors like the presence of clayey formations, their position within the catchment and the availability of suspended particles. The results seem to indicate hillsides as main sources of suspended sediment to the torrents

  9. Closeup view of the Orbiter Discovery as it is suspended ...

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

    Close-up view of the Orbiter Discovery as it is suspended vertically by the hoist in the transfer aisle of the Vehicle Assembly Building at Kennedy Space Center. This view is a detail of the starboard wing of the orbiter. Note the Reinforced Carbon-Carbon panels on the leading edge of the wing, the elevons and the elevon seal panels on the wing's trailing edge. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

  10. Analysis towards VMEM File of a Suspended Virtual Machine

    NASA Astrophysics Data System (ADS)

    Song, Zheng; Jin, Bo; Sun, Yongqing

    With the popularity of virtual machines, forensic investigators are challenged with more complicated situations, among which discovering the evidences in virtualized environment is of significant importance. This paper mainly analyzes the file suffixed with .vmem in VMware Workstation, which stores all pseudo-physical memory into an image. The internal file structure of .vmem file is studied and disclosed. Key information about processes and threads of a suspended virtual machine is revealed. Further investigation into the Windows XP SP3 heap contents is conducted and a proof-of-concept tool is provided. Different methods to obtain forensic memory images are introduced, with both advantages and limits analyzed. We conclude with an outlook.

  11. Transport in Suspended Ultraclean Carbon Nanotube Double Dots

    NASA Astrophysics Data System (ADS)

    Pan, Cheng; Bockrath, Marc

    2014-03-01

    Using split gates, we modulate the charge density along the length of suspended ultraclean single-wall carbon nanotubes to produce pp , pn , np and nn configurations. With pn junctions present, the nanotubes act as a double quantum dot system. We perform transport experiments to investigate Kondo physics in this coupled tunable system. In polarized pp configurations, we observe conductance modulations that we attribute to backscattering induced by a potential step within the nanotube. We estimate the step spatial size from the electron wavelength cutoff of the scattering. We will discuss our latest results.

  12. Connecting source and transport: Suspended sediments in the Nepal Himalayas

    NASA Astrophysics Data System (ADS)

    Andermann, Christoff; Crave, Alain; Gloaguen, Richard; Davy, Philippe; Bonnet, Stéphane

    2012-10-01

    Understanding the dynamics of sediment fluxes is a key issue to constrain modern erosion rates in mountain belts and determine the still debated level of control exerted by precipitation, topography and tectonics. The well defined monsoon seasonality in the Himalayas, together with active tectonics and strong relief provide an ideal environment to assess these possible interactions. For this purpose, we present a new compilation of daily suspended sediment data for 12 stations of the major rivers of the Nepal Himalayas. We analyze the relationships of sediment transport with daily river discharge and precipitation data as well as with morphometric parameters. We show that suspended sediment concentrations vary systematically through the seasons and asynchronously to river discharge displaying a hysteresis effect. This clockwise hysteresis effect disappears when suspended sediment fluxes are directly compared with direct storm discharge. Therefore we attribute the hysteresis effect to groundwater dilution rather than a sediment supply limitation. We infer a rating model to calculate erosion rates directly from long river discharge chronicles. We show that, when normalized by drainage area and mean sediment flux, all rivers exhibit the same trend. This similarity implies that all river basins have the same erosion behavior, independent of location, size and catchment characteristics. Erosion rates calculated from suspended sediment fluxes range between 0.1 and 2.8 mm/yr. The erosion rates of the three main basins of Nepal are in the range 0.9-1.5 mm/yr, Erosion rates in the Higher Himalayas are relatively low (<0.5 mm/yr, except for Kali Gandaki), while in the Lesser Himalayas they range from 0.2 to 2 mm/yr. We propose that material transport in the rivers depends on hillslope sediment supply, which is, in turn, controlled by those rainfalls producing direct runoff. In other words, the rivers in the Nepal Himalayas are supply-limited and the hillsopes as a

  13. Suspended animation-like state protects mice from lethal hypoxia.

    PubMed

    Blackstone, Eric; Roth, Mark B

    2007-04-01

    Joseph Priestley observed the high burn rate of candles in pure oxygen and wondered if people would "live out too fast" if we were in the same environment. We hypothesize that sulfide, a natural reducer of oxygen that is made in many cell types, acts as a buffer to prevent unrestricted oxygen consumption. To test this, we administered sulfide in the form of hydrogen sulfide (H2S) to mice (Mus musculus). As we have previously shown, H2S decreases the metabolic rate of mice by approximately 90% and induces a suspended animation-like state. Mice cannot survive for longer than 20 min when exposed to 5% oxygen. However, if mice are first put into a suspended animation-like state by a 20-min pretreatment with H2S and then are exposed to low oxygen, they can survive for more than 6.5 h in 5% oxygen with no apparent detrimental effects. In addition, if mice are exposed to a 20-min pretreatment with H2S followed by 1 h at 5% oxygen, they can then survive for several hours at oxygen tensions as low as 3%. We hypothesize that prior exposure to H2S reduces oxygen demand, therefore making it possible for the mice to survive with low oxygen supply. These results suggest that H2S may be useful to prevent damage associated with hypoxia. PMID:17414418

  14. Magnetically suspended stepping motors for clean room and vacuum environments

    NASA Astrophysics Data System (ADS)

    Higuchi, Toshiro

    1994-05-01

    To answer the growing needs for super-clean or contact free actuators for uses in clean rooms, vacuum chambers, and space, innovative actuators which combine the functions of stepping motors and magnetic bearings in one body were developed. The rotor of the magnetically suspended stepping motor is suspended like a magnetic bearing and rotated and positioned like a stepping motor. The important trait of the motor is that it is not a simple mixture or combination of a stepping motor and conventional magnetic bearing, but an amalgam of a stepping motor and a magnetic bearing. Owing to optimal design and feed-back control, a toothed stator and rotor are all that are needed structurewise for stable suspension. More than ten types of motors such as linear type, high accuracy rotary type, two-dimensional type, and high vacuum type were built and tested. This paper describes the structure and design of these motors and their performance for such applications as precise positioning rotary table, linear conveyor system, and theta-zeta positioner for clean room and high vacuum use.

  15. IUTAM symposium on hydrodynamic diffusion of suspended particles

    SciTech Connect

    Davis, R.H.

    1995-12-31

    Hydrodynamic diffusion refers to the fluctuating motion of nonBrownian particles (or droplets or bubbles) which occurs in a dispersion due to multiparticle interactions. For example, in a concentrated sheared suspension, particles do not move along streamlines but instead exhibit fluctuating motions as they tumble around each other. This leads to a net migration of particles down gradients in particle concentration and in shear rate, due to the higher frequency of encounters of a test particle with other particles on the side of the test particle which has higher concentration or shear rate. As another example, suspended particles subject to sedimentation, centrifugation, or fluidization, do not generally move relative to the fluid with a constant velocity, but instead experience diffusion-like fluctuations in velocity due to interactions with neighboring particles and the resulting variation in the microstructure or configuration of the suspended particles. In flowing granular materials, the particles interact through direct collisions or contacts (rather than through the surrounding fluid); these collisions also cause the particles to undergo fluctuating motions characteristic of diffusion processes. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  16. Hydrodynamics of Inclusions in Freely Suspended Liquid Crystal Films

    NASA Astrophysics Data System (ADS)

    Qi, Zhiyuan

    Hydrodynamic interaction of pairs of circular inclusions in two-dimensional (2D), fluid smectic membranes suspended in air has been studied systematically. By analyzing their Brownian motion, it is found that the radial mutual mobilities of identical inclusions are independent of their size but that the angular coupling becomes strongly size-dependent when their radius exceeds a characteristic hydrodynamic length. These observations are described well for arbitrary inclusion separations by a model that generalizes the Levine/MacKintosh theory of point-force response functions and uses a boundary-element approach to calculate the mobility matrix for inclusions of finite extent. Beyond that, 2D flow fields generated by a rigid, oscillating post inserted in the film have been measured by analyzing the motion of tracer particles and provide a detailed understanding of the hydrodynamic behavior in the film/gas system. The Brownian diffusion of micron-scale inclusions in freely suspended smectic A liquid crystal films a few nanometers thick and several millimeters in diameter depends strongly on the air surrounding the film. Near atmospheric pressure, the three-dimensionally coupled film/gas system is well described by Hughes/Pailthorpe/White hydrodynamic theory but at lower pressure, the diffusion coefficient increases substantially, tending in high vacuum toward the two-dimensional limit where it is determined by film size. In the absence of air, the films are found to be a nearly ideal physical realization of a two-dimensional, incompressible Newtonian fluid.

  17. Observation of suspended sediments in Mobile Bay, Alabama from satellite

    USGS Publications Warehouse

    Stumpf, Richard P.

    1991-01-01

    As part of a comprehensive geologic study of coastal Alabama and Mississippi, the U.S. Geological Survey is investigating coastal sediment transport in Mobile Bay and the adjacent shelf. Satellite imagery from the NOAA AVHRR is being used to provide data on the variability of spatial patterns in the near-surface suspended sediment concentration. This imagery is processed using atmospheric corrections to remove haze and Rayleigh radiance in order to obtain water reflectances; the reflectances are than converted to approximate sediment concentrations using standard relationships between water reflectance and in situ sediment concentrations. A series of images from early 1990 shows rapid changes in sediment concentrations in response to high river flow of the Alabama-Tombigbee river system. During these times, suspended sediment tends to flow out Mobile Bay without mixing into the eastern lobe of the Bay (Bon Secour Bay). The sediment concentration field also appears to be disturbed by the main ship channel. The sediment plume extends more than 60 km offshore after the peak flow event. One wind event in December 1989 was identified as increasing sediment concentration in the Bay. It is not believed that such an event has been previously observed from satellite.

  18. IUTAM symposium on hydrodynamic diffusion of suspended particles

    NASA Technical Reports Server (NTRS)

    Davis, R. H. (Editor)

    1995-01-01

    Hydrodynamic diffusion refers to the fluctuating motion of nonBrownian particles (or droplets or bubbles) which occurs in a dispersion due to multiparticle interactions. For example, in a concentrated sheared suspension, particles do not move along streamlines but instead exhibit fluctuating motions as they tumble around each other. This leads to a net migration of particles down gradients in particle concentration and in shear rate, due to the higher frequency of encounters of a test particle with other particles on the side of the test particle which has higher concentration or shear rate. As another example, suspended particles subject to sedimentation, centrifugation, or fluidization, do not generally move relative to the fluid with a constant velocity, but instead experience diffusion-like fluctuations in velocity due to interactions with neighboring particles and the resulting variation in the microstructure or configuration of the suspended particles. In flowing granular materials, the particles interact through direct collisions or contacts (rather than through the surrounding fluid); these collisions also cause the particles to undergo fluctuating motions characteristic of diffusion processes. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  19. Controlled ripple texturing of suspended graphene and ultrathin graphite membranes.

    PubMed

    Bao, Wenzhong; Miao, Feng; Chen, Zhen; Zhang, Hang; Jang, Wanyoung; Dames, Chris; Lau, Chun Ning

    2009-09-01

    Graphene is nature's thinnest elastic material and displays exceptional mechanical and electronic properties. Ripples are an intrinsic feature of graphene sheets and are expected to strongly influence electronic properties by inducing effective magnetic fields and changing local potentials. The ability to control ripple structure in graphene could allow device design based on local strain and selective bandgap engineering. Here, we report the first direct observation and controlled creation of one- and two-dimensional periodic ripples in suspended graphene sheets, using both spontaneously and thermally generated strains. We are able to control ripple orientation, wavelength and amplitude by controlling boundary conditions and making use of graphene's negative thermal expansion coefficient (TEC), which we measure to be much larger than that of graphite. These results elucidate the ripple formation process, which can be understood in terms of classical thin-film elasticity theory. This should lead to an improved understanding of suspended graphene devices, a controlled engineering of thermal stress in large-scale graphene electronics, and a systematic investigation of the effect of ripples on the electronic properties of graphene.

  20. Water and suspended sediment division at a stratified tidal junction

    NASA Astrophysics Data System (ADS)

    Buschman, F. A.; Vegt, M.; Hoitink, A. J. F.; Hoekstra, P.

    2013-03-01

    Tidal junctions play a crucial role in the transport of water, salt, and sediment through a delta distributary network. Water, salt and sediment are exchanged at tidal junctions, thereby influencing the transports in the connecting branches and the overall dynamics of the system. This paper presents observations of water, salt and sediment transports in three channels that connect at a stratified tidal junction. Flow variation in one channel was found to lag behind flow variation in a connected channel by more than 1 h, which is largely attributed to channel length differences from the junction to the sea. The water columns in the three channels were periodically stratified during spring tide, whereas the salinity structure represented a salt wedge during neap tide. Salinity differences between the three channels were substantial. The channels contain water bodies of different salinity and act largely independently. Flow velocities in the upper and lower layers differed substantially. Flow in the lower layer was generally in the direction of acceleration produced by the baroclinic pressure gradient. Interestingly, baroclinic pressure gradients were sometimes directed landward, indicating the presence of saltier water at the land side of the estuary. In sharp channel bends close to the junction, secondary flow was strongest at the highest axial flow velocity during spring tide. In one channel bend, these circulations steered the suspended sediment toward the inner bend, which affected the suspended sediment division.