Perspective: Chemical reactions in ionic liquids monitored through the gas (vacuum)/liquid interface.

PubMed

Maier, F; Niedermaier, I; Steinrück, H-P

2017-05-07

This perspective analyzes the potential of X-ray photoelectron spectroscopy under ultrahigh vacuum (UHV) conditions to follow chemical reactions in ionic liquids in situ. Traditionally, only reactions occurring on solid surfaces were investigated by X-ray photoelectron spectroscopy (XPS) in situ. This was due to the high vapor pressures of common liquids or solvents, which are not compatible with the required UHV conditions. It was only recently realized that the situation is very different when studying reactions in Ionic Liquids (ILs), which have an inherently low vapor pressure, and first studies have been performed within the last years. Compared to classical spectroscopy techniques used to monitor chemical reactions, the advantage of XPS is that through the analysis of their core levels all relevant elements can be quantified and their chemical state can be analyzed under well-defined (ultraclean) conditions. In this perspective, we cover six very different reactions which occur in the IL, with the IL, or at an IL/support interface, demonstrating the outstanding potential of in situ XPS to gain insights into liquid phase reactions in the near-surface region.

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

Dong, Xiaohao, E-mail: xiaohao.dong@xfel.eu; Sinn, Harald, E-mail: harald.sinn@xfel.eu; Shu, Deming, E-mail: shu@aps.anl.gov

An artificial channel-cut crystal monochromator for the hard X-Ray beamlines of SASE 1&2, cryogenically cooled by the so-called pulse tube cooler (cryorefrigerator), is currently under development at the European XFEL ( http://www.xfel.eu/ ). The fabrication is on-going. We present here the crystal optical consideration and the novel cooling configuration, according to the X-Ray FEL pulses proprieties. The mechanical design improvements are pointed out as well to implement such kind of monochromator based on the previous similar design.

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

Dong, Xiaohao; Shu, Deming; Sinn, Harald

An artificial channel-cut crystal monochromator for the hard X-Ray beamlines of SASE 1&2, cryogenically cooled by the so-called pulse tube cooler (cryorefrigerator), is currently under development at the European XFEL (http://www.xfel.eu/). The fabrication is on-going. We present here the crystal optical consideration and the novel cooling configuration, according to the X-Ray FEL pulses proprieties. The mechanical design improvements are pointed out as well to implement such kind of monochromator based on the previous similar design.

Spitting cobras: fluid jets in nature as models for technical applications

NASA Astrophysics Data System (ADS)

Balmert, Alexander; Hess, David; Brücker, Christoph; Bleckmann, Horst; Westhoff, Guido

2011-04-01

Spitting cobras defend themselves by ejecting rapid jets of venom through their fangs towards the face of an offender. To generate these jets, the venom delivery system of spitting cobras has some unique adaptations, such as prominent ridges on the surface of the venom channel. We examined the fluid acceleration mechanisms in three spitting cobra species of the genus Naja. To investigate the liquid-flow through the venom channel we built a three-dimensional 60:1 scale model. First we determined the three-dimensional structure of the channel by using microcomputer tomography. With help of the micro computer tomographical data we then created a negative form out of wax. Finally, silicon was casted around the wax form and the wax removed, resulting in a completely transparent model of the cobrás venom channel. The physical-chemical properties of the cobra venom were measured by micro rheometry and tensiometry. Thereafter, an artificial fluid with similar properties was generated. Particle image velocimetry (PIV) was performed to visualize the flow of the artificial liquid in the three-dimensional model. Our experiments show how the surface structure of the venom channel determines the liquid flow through the channel and ultimately the form of the liquid jet. Understanding the biological mechanisms of venom ejection helps to enhance industrial processes such as water jet cutting and cleaning as well as injection methods in technical and medical sectors, e.g. liquid microjet dissection in microsurgery.

The 3D pore structure and fluid dynamics simulation of macroporous monoliths: High permeability due to alternating channel width.

PubMed

Jungreuthmayer, Christian; Steppert, Petra; Sekot, Gerhard; Zankel, Armin; Reingruber, Herbert; Zanghellini, Jürgen; Jungbauer, Alois

2015-12-18

Polymethacrylate-based monoliths have excellent flow properties. Flow in the wide channel interconnected with narrow channels is theoretically assumed to account for favorable permeability. Monoliths were cut into 898 slices in 50nm distances and visualized by serial block face scanning electron microscopy (SBEM). A 3D structure was reconstructed and used for the calculation of flow profiles within the monolith and for calculation of pressure drop and permeability by computational fluid dynamics (CFD). The calculated and measured permeabilities showed good agreement. Small channels clearly flowed into wide and wide into small channels in a repetitive manner which supported the hypothesis describing the favorable flow properties of these materials. This alternating property is also reflected in the streamline velocity which fluctuated. These findings were corroborated by artificial monoliths which were composed of regular (interconnected) cells where narrow cells followed wide cells. In the real monolith and the artificial monoliths with interconnected flow channels similar velocity fluctuations could be observed. A two phase flow simulation showed a lateral velocity component, which may contribute to the transport of molecules to the monolith wall. Our study showed that the interconnection of small and wide pores is responsible for the excellent pressure flow properties. This study is also a guide for further design of continuous porous materials to achieve good flow properties. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Quantum incompatibility of channels with general outcome operator algebras

NASA Astrophysics Data System (ADS)

Kuramochi, Yui

2018-04-01

A pair of quantum channels is said to be incompatible if they cannot be realized as marginals of a single channel. This paper addresses the general structure of the incompatibility of completely positive channels with a fixed quantum input space and with general outcome operator algebras. We define a compatibility relation for such channels by identifying the composite outcome space as the maximal (projective) C*-tensor product of outcome algebras. We show theorems that characterize this compatibility relation in terms of the concatenation and conjugation of channels, generalizing the recent result for channels with quantum outcome spaces. These results are applied to the positive operator valued measures (POVMs) by identifying each of them with the corresponding quantum-classical (QC) channel. We also give a characterization of the maximality of a POVM with respect to the post-processing preorder in terms of the conjugate channel of the QC channel. We consider another definition of compatibility of normal channels by identifying the composite outcome space with the normal tensor product of the outcome von Neumann algebras. We prove that for a given normal channel, the class of normally compatible channels is upper bounded by a special class of channels called tensor conjugate channels. We show the inequivalence of the C*- and normal compatibility relations for QC channels, which originates from the possibility and impossibility of copying operations for commutative von Neumann algebras in C*- and normal compatibility relations, respectively.

UHV-compatible magnetic material for atom optics

NASA Astrophysics Data System (ADS)

Hopkins, S. A.; Hinds, E. A.; Boshier, M. G.

Magnetic videotape is of great interest for trapping and guiding cold atomic vapors, but was hitherto considered unsuitable for manipulating Bose-Einstein condensates (BEC) because of the presumed evolution of gas under vacuum. We have studied the outgassing in vacuum of the most promising tape, Ampex 398 Betacam SP. We find that after cleaning in ethanol and baking for 200 h at 100 °C the magnetic patterns are undisturbed and the outgassing is remarkably small: 4×10-10 Torrls-1cm-2, due mostly to hydrogen. This makes the tape exceedingly attractive for manipulation of BEC.

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

Baker, A. A.; Hesjedal, T.; Diamond Light Source, Didcot OX11 0DE

We present a miniaturized molecular beam epitaxy (miniMBE) system with an outer diameter of 206 mm, optimized for flexible and high-throughput operation. The three-chamber system, used here for oxide growth, consists of a sample loading chamber, a storage chamber, and a growth chamber. The growth chamber is equipped with eight identical effusion cell ports with linear shutters, one larger port for either a multi-pocket electron beam evaporator or an oxygen plasma source, an integrated cryoshroud, retractable beam-flux monitor or quartz-crystal microbalance, reflection high energy electron diffraction, substrate manipulator, main shutter, and quadrupole mass spectrometer. The system can be combined withmore » ultrahigh vacuum (UHV) end stations on synchrotron and neutron beamlines, or equivalently with other complex surface analysis systems, including low-temperature scanning probe microscopy systems. Substrate handling is compatible with most UHV surface characterization systems, as the miniMBE can accommodate standard surface science sample holders. We introduce the design of the system, and its specific capabilities and operational parameters, and we demonstrate the epitaxial thin film growth of magnetoelectric Cr{sub 2}O{sub 3} on c-plane sapphire and ferrimagnetic Fe{sub 3}O{sub 4} on MgO (001)« less

Statistical characteristics of transient enclosure voltage in ultra-high-voltage gas-insulated switchgear

NASA Astrophysics Data System (ADS)

Cai, Yuanji; Guan, Yonggang; Liu, Weidong

2017-06-01

Transient enclosure voltage (TEV), which is a phenomenon induced by the inner dielectric breakdown of SF6 during disconnector operations in a gas-insulated switchgear (GIS), may cause issues relating to shock hazard and electromagnetic interference to secondary equipment. This is a critical factor regarding the electromagnetic compatibility of ultra-high-voltage (UHV) substations. In this paper, the statistical characteristics of TEV at UHV level are collected from field experiments, and are analyzed and compared to those from a repeated strike process. The TEV waveforms during disconnector operations are recorded by a self-developed measurement system first. Then, statistical characteristics, such as the pulse number, duration of pulses, frequency components, magnitude and single pulse duration, are extracted. The transmission line theory is introduced to analyze the TEV and is validated by the experimental results. Finally, the relationship between the TEV and the repeated strike process is analyzed. This proves that the pulse voltage of the TEV is proportional to the corresponding breakdown voltage. The results contribute to the definition of the standard testing waveform of the TEV, and can aid the protection of electronic devices in substations by minimizing the threat of this phenomenon.

Impact of alternative regeneration methods on genetic diversity in coastal Douglas-fir

USGS Publications Warehouse

Adams, W.T.; Zuo, J.; Shimizu, J.Y.; Tappeiner, J. C.

1998-01-01

Genetic implications of natural and artificial regeneration following three regeneration methods (group selection, shelterwood, and clearcut) were investigated in coastal Douglas-fir (Pseudotsuga menziesii var. menziesii [Mirb.] Franco) using genetic markers (17 allozyme loci). In general, harvesting followed by either natural or artificial regeneration resulted in offspring populations little altered from those in the previous generation. Cutting the smallest trees to form shelterwoods, however, resulted in the removal of rare, presumably deleterious, alleles, such that slightly fewer alleles per locus were observed among residual trees (2.76) and natural regeneration (2.75) than found in uncut (control) stands (2.86). Thus, although the shelterwood regime appears quite compatible with gene conservation, it would be best to leave parent trees of a range of sizes in shelterwoods designated as gene conservation reserves, in order to maximize the number of alleles (regardless of current adaptive value) in naturally regenerated offspring. Seedling stocks used for artificial regeneration in clearcut, shelterwood, and group selection stands (7 total) had significantly greater levels of genetic diversity, on average, than found in natural regeneration. This is probably because the seeds used in artificial seedling stocks came from many wild stands and thus, sampled more diversity than found in single populations. For. Sci. 44(3): 390-396.

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

Colldelram, Carles, E-mail: ccolldelram@cells.es; Nicolas, Josep, E-mail: jnicolas@cells.es; Nikitina, Liudmila, E-mail: lnikitina@cells.es

In this work we report the design and performance of a novel compact in-vacuum actuator, designed to be compatible with all the motions required for the scissor-type ESRF mirror bender. These mirror benders include several linear actuators, which drive the mirror bending torques, as well as the main alignment motions such as pitch and translation along the normal to the mirror surface. The motions are provided by compact linear actuators, which consist of motor, reduction, spindle and nut, encapsulated on a closed air volume to provide vacuum compatibility. The actuator includes a hydroformed bellows to transmit the force to themore » actuator tip, and an electrical feedthrough for the motor cables. The design boundaries for these actuators are quite tight, as they must be integrated in a narrow volume, must be UHV compatible and must provide high resolution, for a relatively high load. As a result, they have limited mechanical performance, and in some cases poor reliability. To overcome these problems, we designed and implemented a different concept. In the proposed concept, the motor rotation is converted onto a linear motion by means of a cam instead of a spindle and a nut. This allows for much shorter and stiffer transmission system, with similar dimensions. The vacuum compatibility is intrinsic for this solution, since the whole mechanism of the actuator is UHV compatible. All motions are preloaded and guided by vacuum compatible (hybrid metal-ceramics) ball bearings. This allows the system reaching a repeatability and backlash well within the micron. The absence of friction allows for a high reliability and releases the maintenance needs of the system. The transmission is intrinsically irreversible, and the system can hold a load of 250 N within a few nanometers without any holding current on the motors. This allows the system to move reliably also in micro-stepping mode, providing a resolution well below the half-step nominal resolution of 100 nm. Performances have been tested on a prototype. We report the results of the tests obtained in air and in vacuum after bake-out. Two units of the new actuator have been installed at the photoemission beamline of ALBA (CIRCE) and are routinely used to align the 3 µm spot on the field of view of the Photoemission Electron Microscope. The absence of any noticeable backlash, or any friction effect and the reliability of the micro-stepping motion has simplified very much the alignment of the photon beam, reducing the alignment process to few minutes. The excellent performances and relatively high load capacity of this new compact actuator make of it a versatile element to be integrated in other systems requiring reliable in-vacuum positioning.« less

Maxillofacial reconstruction using custom-made artificial bones fabricated by inkjet printing technology.

PubMed

Saijo, Hideto; Igawa, Kazuyo; Kanno, Yuki; Mori, Yoshiyuki; Kondo, Kayoko; Shimizu, Koutaro; Suzuki, Shigeki; Chikazu, Daichi; Iino, Mitsuki; Anzai, Masahiro; Sasaki, Nobuo; Chung, Ung-il; Takato, Tsuyoshi

2009-01-01

Ideally, artificial bones should be dimensionally compatible with deformities, and be biodegradable and osteoconductive; however, there are no artificial bones developed to date that satisfy these requirements. We fabricated novel custom-made artificial bones from alpha-tricalcium phosphate powder using an inkjet printer and implanted them in ten patients with maxillofacial deformities. The artificial bones had dimensional compatibility in all the patients. The operation time was reduced due to minimal need for size adjustment and fixing manipulation. The postsurgical computed tomography analysis detected partial union between the artificial bones and host bone tissues. There were no serious adverse reactions. These findings provide support for further clinical studies of the inkjet-printed custom-made artificial bones.

Custom sample environments at the ALBA XPEEM.

PubMed

Foerster, Michael; Prat, Jordi; Massana, Valenti; Gonzalez, Nahikari; Fontsere, Abel; Molas, Bernat; Matilla, Oscar; Pellegrin, Eric; Aballe, Lucia

2016-12-01

A variety of custom-built sample holders offer users a wide range of non-standard measurements at the ALBA synchrotron PhotoEmission Electron Microscope (PEEM) experimental station. Some of the salient features are: an ultrahigh vacuum (UHV) suitcase compatible with many offline deposition and characterization systems, built-in electromagnets for uni- or biaxial in-plane (IP) and out-of-plane (OOP) fields, as well as the combination of magnetic fields with electric fields or current injection. Electronics providing a synchronized sinusoidal signal for sample excitation enable time-resolved measurements at the 500MHz storage ring RF frequency. Copyright © 2016 Elsevier B.V. All rights reserved.

Artificial Intelligence Based Selection of Optimal Cutting Tool and Process Parameters for Effective Turning and Milling Operations

NASA Astrophysics Data System (ADS)

Saranya, Kunaparaju; John Rozario Jegaraj, J.; Ramesh Kumar, Katta; Venkateshwara Rao, Ghanta

2016-06-01

With the increased trend in automation of modern manufacturing industry, the human intervention in routine, repetitive and data specific activities of manufacturing is greatly reduced. In this paper, an attempt has been made to reduce the human intervention in selection of optimal cutting tool and process parameters for metal cutting applications, using Artificial Intelligence techniques. Generally, the selection of appropriate cutting tool and parameters in metal cutting is carried out by experienced technician/cutting tool expert based on his knowledge base or extensive search from huge cutting tool database. The present proposed approach replaces the existing practice of physical search for tools from the databooks/tool catalogues with intelligent knowledge-based selection system. This system employs artificial intelligence based techniques such as artificial neural networks, fuzzy logic and genetic algorithm for decision making and optimization. This intelligence based optimal tool selection strategy is developed using Mathworks Matlab Version 7.11.0 and implemented. The cutting tool database was obtained from the tool catalogues of different tool manufacturers. This paper discusses in detail, the methodology and strategies employed for selection of appropriate cutting tool and optimization of process parameters based on multi-objective optimization criteria considering material removal rate, tool life and tool cost.

Method for producing an atomic oxygen beam

NASA Technical Reports Server (NTRS)

Outlaw, Ronald A. (Inventor)

1989-01-01

A method for producing an atomic oxygen beam is provided by the present invention. First, a material 10' is provided which dissociates molecular oxygen and dissolves atomic oxygen into its bulk. Next, molecular oxygen is exposed to entrance surface 11' of material 10'. Next, material 10' is heated by heater 17' to facilitate the permeation of atomic oxygen through material 10' to the UHV side 12'. UHV side 12' is interfaced with an ultra-high vacuum (UHV) environment provided by UHV pump 15'. The atomic oxygen on the UHV side 12' is excited to a non-binding state by exciter 14' thus producing the release of atomic oxygen to form an atomic oxygen beam 35'.

Simulated-use validation of a sponge ATP method for determining the adequacy of manual cleaning of endoscope channels.

PubMed

Alfa, Michelle J; Olson, Nancy

2016-05-04

The objective of this study was to validate the relative light unit (RLU) cut-off of adequate cleaning of flexible colonoscopes for an ATP (adenosine tri-phosphate) test kit that used a sponge channel collection method. This was a simulated-use study. The instrument channel segment of a flexible colonoscope was soiled with ATS (artificial test soil) containing approximately 8 Log10 Enterococcus faecalis and Pseudomonas aeruginosa/mL. Full cleaning, partial cleaning and no cleaning were evaluated for ATP, protein and bacterial residuals. Channel samples were collected using a sponge device to assess residual RLUs. Parallel colonoscopes inoculated and cleaned in the same manner were sampled using the flush method to quantitatively assess protein and bacterial residuals. The protein and viable count benchmarks for adequate cleaning were <6.4 ug/cm(2) and <4 Log10 cfu/cm(2). The negative controls for the instrument channel, over the course of the study remained low with on average 14 RLUs, 0.04 ug/cm(2) protein and 0.025 Log10 cfu/cm(2). Partial cleaning resulted in an average of 6601 RLUs, 3.99 ug/cm(2), 5.25 Log10 cfu/cm(2) E. faecalis and 4.48 Log10 cfu/cm(2) P. aeruginosa. After full cleaning, the average RLU was 29 (range 7-71 RLUs) and the average protein, E. faecalis and P. aeruginosa residuals were 0.23 ug/cm(2), 0.79 and 1.61 Log10 cfu/cm(2), respectively. The validated cut-off for acceptable manual cleaning was set at ≤100 RLUs for the sponge collected channel ATP test kit.

Joint services electronics program

NASA Astrophysics Data System (ADS)

Flynn, George W.; Osgood, Richard M., Jr.

1988-05-01

Several milestones have been reached in GaAs research. The first active GaAs device, a 1 micrometer channel width MESFET, has been made at Columbia. This device is a basic building block in the GaAs CCD program. GaAs surface studies have also born fruit. UV light has been found to oxidize rapidly the surface of GaAs in an UHV environment containing traces of water vapor and O2. The mechanism appears to be related to the generation of hot photocarriers.

Channel Evolution Following Avulsion: an Example from the Yellow River Delta

NASA Astrophysics Data System (ADS)

Zheng, S.

2017-12-01

Long-term field observation of morphological adjustments of rivers following avulsions is lacked when studying the evolution of avulsive channel on deltas. Avulsion at the Yellow River Delta (YRD) is frequent with average lifespan of channels of only about a decade. The Qing-shui-gou channel, the recent lobe on the YRD, provides a rare opportunity for investigating channel evolution following artificial avulsion. The reasons for its longer lifespan also needs investigation of the channel evolution. In this study, we comprehensively analyzed the geomorphic adjustment of the channel based on filed survey data during 1976-2014. The evolution of the channel was impacted by anthropogenic activities, including artificial avulsion at the downstream channel reaches in 1996, alteration of runoff and sediment load through Water and Sediment Regulation Scheme (WSRS), construction of levees and dikes. Analysis on channel geometry showed that avulsions in 1976 and in 1996 both caused short-term (1 2 years) erosion at the upstream channel reaches. Following the avulsion in 1976, massive aggradation occurred at the channel reaches at the downstream of the avulsion point. A single-thread channel gradually formed, widened and enlarged as channel bed under-cut on the deposition material. As delta extended seaward and the longitudinal slope decreased with time, aggradation occurred and an alluvial ridge formed. The ratio of lateral slope to the longitudinal slope (i.e. gradient advantage) and the relative super-elevation of the channel were calculated to estimate the possibility of avulsion at the channel in the late 1990. Results showed that the slope ratio was greater than 20 locally and super-elevation near its critical value for avulsion. The fact, that natural avulsion did not occurred despite of high values of gradient advantage and super elevation, may indicate that they are not sufficient conditions for avulsion at highly human-controlled rivers, where channel boundaries are constrained by dikes and bankfull discharge rarely occur. The Qing-shui-gou channel has been eroded and deepened since 2002 when the WSRS was implemented. Although channel erosion rates caused by WSRS decreased with time, the risk of avulsion has been reduced. This may also help explain the relative longer life-span of the Qing-shui-gou channel.

Challenges faced in the clinical application of artificial anal sphincters.

PubMed

Wang, Ming-hui; Zhou, Ying; Zhao, Shuang; Luo, Yun

2015-09-01

Fecal incontinence is an unresolved problem, which has a serious effect on patients, both physically and psychologically. For patients with severe symptoms, treatment with an artificial anal sphincter could be a potential option to restore continence. Currently, the Acticon Neosphincter is the only device certified by the US Food and Drug Administration. In this paper, the clinical safety and efficacy of the Acticon Neosphincter are evaluated and discussed. Furthermore, some other key studies on artificial anal sphincters are presented and summarized. In particular, this paper highlights that the crucial problem in this technology is to maintain long-term biomechanical compatibility between implants and surrounding tissues. Compatibility is affected by changes in both the morphology and mechanical properties of the tissues surrounding the implants. A new approach for enhancing the long-term biomechanical compatibility of implantable artificial sphincters is proposed based on the use of smart materials.

Fabrication of 4H-SiC n-channel IGBTs with ultra high blocking voltage

NASA Astrophysics Data System (ADS)

Yang, Xiaolei; Tao, Yonghong; Yang, Tongtong; Huang, Runhua; Song, Bai

2018-03-01

Owing to the conductivity modulation of silicon carbide (SiC) bipolar devices, n-channel insulated gate bipolar transistors (n-IGBTs) have a significant advantage over metal oxide semiconductor field effect transistors (MOSFETs) in ultra high voltage (UHV) applications. In this paper, backside grinding and laser annealing process were carried out to fabricate 4H-SiC n-IGBTs. The thickness of a drift layer was 120 μm, which was designed for a blocking voltage of 13 kV. The n-IGBTs carried a collector current density of 24 A/cm2 at a power dissipation of 300 W/cm2 when the gate voltage was 20 V, with a differential specific on-resistance of 140 mΩ·cm2.

Ultra high vacuum heating and rotating specimen stage

DOEpatents

Coombs, III, Arthur W.

1995-01-01

A heating and rotating specimen stage provides for simultaneous specimen heating and rotating. The stage is ideally suited for operation in ultrahigh vacuum (1.times.10.sup.-9 torr or less), but is useful at atmosphere and in pressurized systems as well. A specimen is placed on a specimen holder that is attached to a heater that, in turn, is attached to a top housing. The top housing is rotated relative to a bottom housing and electrically connected thereto by electrically conductive brushes. This stage is made of materials that are compatible with UHV, able to withstand high temperatures, possess low outgassing rates, are gall and seize resistant, and are able to carry substantial electrical loading without overheating.

A versatile UHV transport and measurement chamber for neutron reflectometry under UHV conditions

NASA Astrophysics Data System (ADS)

Syed Mohd, A.; Pütter, S.; Mattauch, S.; Koutsioubas, A.; Schneider, H.; Weber, A.; Brückel, T.

2016-12-01

We report on a versatile mini ultra-high vacuum (UHV) chamber which is designed to be used on the MAgnetic Reflectometer with high Incident Angle of the Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum in Garching, Germany. Samples are prepared in the adjacent thin film laboratory by molecular beam epitaxy and moved into the compact chamber for transfer without exposure to ambient air. The chamber is based on DN 40 CF flanges and equipped with sapphire view ports, a small getter pump, and a wobble stick, which serves also as sample holder. Here, we present polarized neutron reflectivity measurements which have been performed on Co thin films at room temperature in UHV and in ambient air in a magnetic field of 200 mT and in the Q-range of 0.18 Å-1. The results confirm that the Co film is not contaminated during the polarized neutron reflectivity measurement. Herewith it is demonstrated that the mini UHV transport chamber also works as a measurement chamber which opens new possibilities for polarized neutron measurements under UHV conditions.

A versatile UHV transport and measurement chamber for neutron reflectometry under UHV conditions.

PubMed

Syed Mohd, A; Pütter, S; Mattauch, S; Koutsioubas, A; Schneider, H; Weber, A; Brückel, T

2016-12-01

We report on a versatile mini ultra-high vacuum (UHV) chamber which is designed to be used on the MAgnetic Reflectometer with high Incident Angle of the Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum in Garching, Germany. Samples are prepared in the adjacent thin film laboratory by molecular beam epitaxy and moved into the compact chamber for transfer without exposure to ambient air. The chamber is based on DN 40 CF flanges and equipped with sapphire view ports, a small getter pump, and a wobble stick, which serves also as sample holder. Here, we present polarized neutron reflectivity measurements which have been performed on Co thin films at room temperature in UHV and in ambient air in a magnetic field of 200 mT and in the Q-range of 0.18 Å -1 . The results confirm that the Co film is not contaminated during the polarized neutron reflectivity measurement. Herewith it is demonstrated that the mini UHV transport chamber also works as a measurement chamber which opens new possibilities for polarized neutron measurements under UHV conditions.

Radio-frequency response of single pores and artificial ion channels

NASA Astrophysics Data System (ADS)

Kim, H. S.; Ramachandran, S.; Stava, E.; van der Weide, D. W.; Blick, R. H.

2011-09-01

Intercellular communication relies on ion channels and pores in cell membranes. These protein-formed channels enable the exchange of ions and small molecules to electrically and/or chemically interact with the cells. Traditionally, recordings on single-ion channels and pores are performed in the dc regime, due to the extremely high impedance of these molecular junctions. This paper is intended as an introduction to radio-frequency (RF) recordings of single-molecule junctions in bilipid membranes. First, we demonstrate how early approaches to using microwave circuitry as readout devices for ion channel formation were realized. The second step will then focus on how to engineer microwave coupling into the high-impedance channel by making use of bio-compatible micro-coaxial lines. We then demonstrate integration of an ultra-broadband microwave circuit for the direct sampling of single α-hemolysin pores in a suspended bilipid membrane. Simultaneous direct current recordings reveal that we can monitor and correlate the RF transmission signal. This enables us to relate the open-close states of the direct current to the RF signal. Altogether, our experiments lay the ground for an RF-readout technique to perform real-time in vitro recordings of pores. The technique thus holds great promise for research and drug screening applications. The possible enhancement of sampling rates of single channels and pores by the large recording bandwidth will allow us to track the passage of single ions.

Understanding Single-Thread Meandering Rivers with High Sinuosity on Mars through Chemical Precipitation Experiments

NASA Astrophysics Data System (ADS)

Lim, Y.; Kim, W.

2015-12-01

Meandering rivers are extremely ubiquitous on Earth, yet it is only recently that single-thread experimental channels with low sinuosity have been created. In these recent experiments, as well as in natural rivers, vegetation plays a crucial role in maintaining a meandering pattern by adding cohesion to the bank and inhibiting erosion. The ancient, highly sinuous channels found on Mars are enigmatic because presumably vegetation did not exist on ancient Mars. Under the hypothesis that Martian meandering rivers formed by chemical precipitation on levees and flood plain deposits, we conducted carbonate flume experiments to investigate the formation and evolution of a single-thread meander pattern without vegetation. The flow recirculating in the flume is designed to accelerate chemical reactions - dissolution of limestone using CO2 gas to produce artificial spring water and precipitation of carbonates to increase cohesion- with precise control of water discharge, sediment discharge, and temperature. Preliminary experiments successfully created a single-thread meandering pattern through chemical processes. Carbonate deposits focused along the channel sides improved the bank stability and made them resistant to erosion, which led to a stream confined in a narrow path. The experimental channels showed lateral migration of the bend through cut bank and point bar deposits; intermittent floods created overbank flow and encouraged cut bank erosion, which enhanced lateral migration of the channel, while increase in sediment supply improved lateral point bar deposition, which balanced erosion and deposition rates. This mechanism may be applied to terrestrial single-thread and/or meandering rivers with little to no vegetation or before its introduction to Earth and also provide the link between meandering river records on Mars to changes in Martian surface conditions.

The design and implementation of on-line monitoring system for UHV compact shunt capacitors

NASA Astrophysics Data System (ADS)

Tao, Weiliang; Ni, Xuefeng; Lin, Hao; Jiang, Shengbao

2017-08-01

Because of the large capacity and compact structure of the UHV compact shunt capacitor, it is difficult to take effective measures to detect and prevent the faults. If the fault capacitor fails to take timely maintenance, it will pose a threat to the safe operation of the system and the life safety of the maintenance personnel. The development of UHV compact shunt capacitor on-line monitoring system can detect and record the on-line operation information of UHV compact shunt capacitors, analyze and evaluate the early fault warning signs, find out the fault capacitor or the capacitor with fault symptom, to ensure safe and reliable operation of the system.

Electrodeless Plasma Source: Phase II Update

NASA Astrophysics Data System (ADS)

Prager, James; Ziemba, Timothy; Miller, Kenneth

2012-10-01

Eagle Harbor Technologies, in collaboration with the University of Washington, has developed a low-impurity, electrode-less plasma source (EPS) for start-up and source plasma injection for fusion science applications. In order to not interfere with the experiment, a pre-ionizer/plasma source must meet a few critical criteria including low impurity production, low electromagnetic interference (EMI), and minimal disruption to the magnetic geometry of the experiment. This system was designed to be UHV compatible and bakable. Here we present the results of the EPS Phase II upgrade. The output plasma density was increased by two orders of magnitude to >10^17 m-3 in hydrogen with no magnetic field injected. EPS system integration with the HIT-SI experiment has begun.

Ultra high vacuum heating and rotating specimen stage

DOEpatents

Coombs, A.W. III

1995-05-02

A heating and rotating specimen stage provides for simultaneous specimen heating and rotating. The stage is ideally suited for operation in ultrahigh vacuum (1{times}10{sup {minus}9} torr or less), but is useful at atmosphere and in pressurized systems as well. A specimen is placed on a specimen holder that is attached to a heater that, in turn, is attached to a top housing. The top housing is rotated relative to a bottom housing and electrically connected thereto by electrically conductive brushes. This stage is made of materials that are compatible with UHV, able to withstand high temperatures, possess low outgassing rates, are gall and seize resistant, and are able to carry substantial electrical loading without overheating. 5 figs.

Interfacial and Thin Film Chemistry in Electron Device Fabrication

DTIC Science & Technology

1990-11-20

mounted on our UHV surface analysis system, and J. Forster and D. V. Podlesnik of the IBM General Technology Division. The following discussion...IBM (East Fishkill). The system being built consists of three chambers: one UHV analysis chamber, one UHV reaction chamber and one high pressure...system will be equipped with several surface analysis and cleaning techniques. Fourier transform infrared spectrometry will be used to do attenuated

Tuning the allosteric regulation of artificial muscarinic and dopaminergic ligand-gated potassium channels by protein engineering of G protein-coupled receptors

PubMed Central

Moreau, Christophe J.; Revilloud, Jean; Caro, Lydia N.; Dupuis, Julien P.; Trouchet, Amandine; Estrada-Mondragón, Argel; Nieścierowicz, Katarzyna; Sapay, Nicolas; Crouzy, Serge; Vivaudou, Michel

2017-01-01

Ligand-gated ion channels enable intercellular transmission of action potential through synapses by transducing biochemical messengers into electrical signal. We designed artificial ligand-gated ion channels by coupling G protein-coupled receptors to the Kir6.2 potassium channel. These artificial channels called ion channel-coupled receptors offer complementary properties to natural channels by extending the repertoire of ligands to those recognized by the fused receptors, by generating more sustained signals and by conferring potassium selectivity. The first artificial channels based on the muscarinic M2 and the dopaminergic D2L receptors were opened and closed by acetylcholine and dopamine, respectively. We find here that this opposite regulation of the gating is linked to the length of the receptor C-termini, and that C-terminus engineering can precisely control the extent and direction of ligand gating. These findings establish the design rules to produce customized ligand-gated channels for synthetic biology applications. PMID:28145461

Wireless Visual Sensor Network Resource Allocation using Cross-Layer Optimization

DTIC Science & Technology

2009-01-01

Rate Compatible Punctured Convolutional (RCPC) codes for channel...vol. 44, pp. 2943–2959, November 1998. [22] J. Hagenauer, “ Rate - compatible punctured convolutional codes (RCPC codes ) and their applications,” IEEE... coding rate for H.264/AVC video compression is determined. At the data link layer, the Rate - Compatible Puctured Convolutional (RCPC) channel coding

A reconfigurable image tube using an external electronic image readout

NASA Astrophysics Data System (ADS)

Lapington, J. S.; Howorth, J. R.; Milnes, J. S.

2005-08-01

We have designed and built a sealed tube microchannel plate (MCP) intensifier for optical/NUV photon counting applications suitable for 18, 25 and 40 mm diameter formats. The intensifier uses an electronic image readout to provide direct conversion of event position into electronic signals, without the drawbacks associated with phosphor screens and subsequent optical detection. The Image Charge technique is used to remove the readout from the intensifier vacuum enclosure, obviating the requirement for additional electrical vacuum feedthroughs and for the readout pattern to be UHV compatible. The charge signal from an MCP intensifier is capacitively coupled via a thin dielectric vacuum window to the electronic image readout, which is external to the sealed intensifier tube. The readout pattern is a separate item held in proximity to the dielectric window and can be easily detached, making the system easily reconfigurable. Since the readout pattern detects induced charge and is external to the tube, it can be constructed as a multilayer, eliminating the requirement for narrow insulator gaps and allowing it to be constructed using standard PCB manufacturing tolerances. We describe two readout patterns, the tetra wedge anode (TWA), an optimized 4 electrode device similar to the wedge and strip anode (WSA) but with a factor 2 improvement in resolution, and an 8 channel high speed 50 ohm device, both manufactured as multilayer PCBs. We present results of the detector imaging performance, image resolution, linearity and stability, and discuss the development of an integrated readout and electronics device based on these designs.

Portable mini-chamber for temperature dependent studies using small angle and wide angle x-ray scattering

NASA Astrophysics Data System (ADS)

Dev, Arun Singh; Kumar, Dileep; Potdar, Satish; Pandit, Pallavi; Roth, Stephan V.; Gupta, Ajay

2018-04-01

The present work describes the design and performance of a vacuum compatible portable mini chamber for temperature dependent GISAXS and GIWAXS studies of thin films and multilayer structures. The water cooled body of the chamber allows sample annealing up to 900 K using ultra high vacuum compatible (UHV) pyrolytic boron nitride heater, thus making it possible to study the temperature dependent evolution of structure and morphology of two-dimensional nanostructured materials. Due to its light weight and small size, the chamber is portable and can be accommodated at synchrotron facilities worldwide. A systematic illustration of the versatility of the chamber has been demonstrated at beamline P03, PETRA-III, DESY, Hamburg, Germany. Temperature dependent grazing incidence small angle x-ray scattering (GISAXS) and grazing incidence wide angle x-ray scattering (GIWAXS) measurements were performed on oblique angle deposited Co/Ag multilayer structure, which jointly revealed that the surface diffusion in Co columns in Co/Ag multilayer enhances by increasing temperature from RT to ˜573 K. This results in a morphology change from columnar tilted structure to densely packed morphological isotropic multilayer.

Substantiation of artificial composite-structure roof construction in top-down cut-and-fill stoping

NASA Astrophysics Data System (ADS)

Rukavishnikov, GD; Neverov, SA; Neverov, AA

2018-03-01

It has been found efficient and safe to use top-down cut-and-fill stoping with saving of the artificial backfill cost and material through the use of a solid nonuniform material composed of two components (layers). It is shown that the artificial roof can be advanced after a stope without essential change in the stope condition as compared with the classical top-down slice method, which provides higher safety of mining.

Artificial dirt: microfluidic substrates for nematode neurobiology and behavior.

PubMed

Lockery, S R; Lawton, K J; Doll, J C; Faumont, S; Coulthard, S M; Thiele, T R; Chronis, N; McCormick, K E; Goodman, M B; Pruitt, B L

2008-06-01

With a nervous system of only 302 neurons, the free-living nematode Caenorhabditis elegans is a powerful experimental organism for neurobiology. However, the laboratory substrate commonly used in C. elegans research, a planar agarose surface, fails to reflect the complexity of this organism's natural environment, complicates stimulus delivery, and is incompatible with high-resolution optophysiology experiments. Here we present a new class of microfluidic devices for C. elegans neurobiology and behavior: agarose-free, micron-scale chambers and channels that allow the animals to crawl as they would on agarose. One such device mimics a moist soil matrix and facilitates rapid delivery of fluid-borne stimuli. A second device consists of sinusoidal channels that can be used to regulate the waveform and trajectory of crawling worms. Both devices are thin and transparent, rendering them compatible with high-resolution microscope objectives for neuronal imaging and optical recording. Together, the new devices are likely to accelerate studies of the neuronal basis of behavior in C. elegans.

Non-contact inline monitoring of thermoplastic CFRP tape quality using air-coupled ultrasound

NASA Astrophysics Data System (ADS)

Essig, W.; Fey, P.; Meiler, S.; Kreutzbruck, M.

2017-02-01

Beginning with the aerospace industry, fiber reinforced plastics have spread towards many applications such as automotive, civil engineering as well as sports and leisure articles. Their superior strength and stiffness to mass ratio made them the number one material for achieving high performance. Especially continuous fiber reinforced plastics allow for the construction of structures which are custom tailored to their mechanical loads by adjusting the paths of the fibers to the loading direction. The two main constituents of CFRP are carbon fibers and matrix. Two possibilities for matrix material exist: thermosetting and thermoplastic matrix. While thermosetting matrix may yield better properties with respect to thermal loads, thermoplasticity opens a wide range of applications due to weldability, shapeability, and compatibility to e.g. injection molded thermoplastic materials. Thin (0.1 mm) thermoplastic continuous fiber CFRP tapes with a width of 100 mm were examined using air-coupled ultrasound. Transducers were arranged in reflection as well as transmission setup. By slanted incidence of the ultrasound on the tape surface, guided waves were excited in the material in fiber direction and perpendicular to the fiber direction. Artificial defects - fiber cuts, matrix cuts, circular holes, low velocity impacts from tool drop, and sharp bends - were produced. Experiments on a stationary tape showed good detectability of all artificial defects by guided waves. Also the effects of variation in material properties, fiber volume content and fiber matrix adhesion being the most relevant, on guided wave propagation were examined, to allow for quality assessment. Guided wave measurements were supported by destructive analysis. Also an apparatus containing one endless loop of CFRP tape was constructed and built to simulate inline testing of CFRP tapes, as it would be employed in a CFRP tape production environment or at a CFRP tape processing facility. The influences of tape conveying speed on detectability of artificial defects as well as material properties were elaborated and recommendations for implementation in production scale inline monitoring are given.

Highly precise and compact ultrahigh vacuum rotary feedthrough.

PubMed

Aiura, Y; Kitano, K

2012-03-01

The precision and rigidity of compact ultrahigh vacuum (UHV) rotary feedthroughs were substantially improved by preparing and installing an optimal crossed roller bearing with mounting holes. Since there are mounting holes on both the outer and inner races, the bearing can be mounted directly to rotary and stationary stages without any fixing plates and housing. As a result, it is possible to increase the thickness of the bearing or the size of the rolling elements in the bearing without increasing the distance between the rotating and fixing International Conflat flanges of the UHV rotary feedthrough. Larger rolling elements enhance the rigidity of the UHV rotary feedthrough. Moreover, owing to the structure having integrated inner and outer races and mounting holes, the performance is almost entirely unaffected by the installation of the bearing, allowing for a precise optical encoder to be installed in the compact UHV rotary feedthrough. Using position feedback via a worm gear system driven by a stepper motor and a precise rotary encoder, the actual angle of the compact UHV rotary feedthrough can be controlled with extremely high precision.

Highly precise and compact ultrahigh vacuum rotary feedthrough

NASA Astrophysics Data System (ADS)

Aiura, Y.; Kitano, K.

2012-03-01

The precision and rigidity of compact ultrahigh vacuum (UHV) rotary feedthroughs were substantially improved by preparing and installing an optimal crossed roller bearing with mounting holes. Since there are mounting holes on both the outer and inner races, the bearing can be mounted directly to rotary and stationary stages without any fixing plates and housing. As a result, it is possible to increase the thickness of the bearing or the size of the rolling elements in the bearing without increasing the distance between the rotating and fixing International Conflat flanges of the UHV rotary feedthrough. Larger rolling elements enhance the rigidity of the UHV rotary feedthrough. Moreover, owing to the structure having integrated inner and outer races and mounting holes, the performance is almost entirely unaffected by the installation of the bearing, allowing for a precise optical encoder to be installed in the compact UHV rotary feedthrough. Using position feedback via a worm gear system driven by a stepper motor and a precise rotary encoder, the actual angle of the compact UHV rotary feedthrough can be controlled with extremely high precision.

Strain-free polished channel-cut crystal monochromators: a new approach and results

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

Kasman, Elina; Montgomery, Jonathan; Huang, XianRong

The use of channel-cut crystal monochromators has been traditionally limited to applications that can tolerate the rough surface quality from wet etching without polishing. We have previously presented and discussed the motivation for producing channel cut crystals with strain-free polished surfaces [1]. Afterwards, we have undertaken an effort to design and implement an automated machine for polishing channel-cut crystals. The initial effort led to inefficient results. Since then, we conceptualized, designed, and implemented a new version of the channel-cut polishing machine, now called C-CHiRP (Channel-Cut High Resolution Polisher), also known as CCPM V2.0. The new machine design no longer utilizesmore » Figure-8 motion that mimics manual polishing. Instead, the polishing is achieved by a combination of rotary and linear functions of two coordinated motion systems. Here we present the new design of C-CHiRP, its capabilities and features. Multiple channel-cut crystals polished using the C-CHiRP have been deployed into several beamlines at the Advanced Photon Source (APS). We present the measurements of surface finish, flatness, as well as topography results obtained at 1-BM of APS, as compared with results typically achieved when polishing flat-surface monochromator crystals using conventional polishing processes. Limitations of the current machine design, capabilities and considerations for strain-free polishing of highly complex crystals are also discussed, together with an outlook for future developments and improvements.« less

Demonstration of 4 lanes of 4 × 100 Gbps DMT transmission with channel spacing of 50-GHz compatible with DWDM

NASA Astrophysics Data System (ADS)

Xu, Yuming; Yu, Jianjun; Li, Xinying; Xiao, Jiangnan

2017-07-01

We experimentally demonstrate 4 lanes of 416-Gb/s discrete multi-tone (DMT) transmission with 50-GHz channel spacing. This is the first demonstration of 4 × 100 G transmission with less than 100-GHz channel spacing and it can be compatible with dense wavelength division multiplexing (DWDM).

Design of weak link channel-cut crystals for fast QEXAFS monochromators

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

Polheim, O. von, E-mail: vonpolheim@uni-wuppertal.de; Müller, O.; Lützenkirchen-Hecht, D.

2016-07-27

A weak link channel-cut crystal, optimized for dedicated Quick EXAFS monochromators and measurements, was designed using finite element analysis. This channel-cut crystal offers precise detuning capabilities to enable suppression of higher harmonics in the virtually monochromatic beam. It was optimized to keep the detuning stable, withstanding the mechanical load, which occurs during oscillations with up to 50 Hz. First tests at DELTA (Dortmund, Germany), proved the design.

Evolution of abandoned channels: Insights on controlling factors in a multi-pressure river system

NASA Astrophysics Data System (ADS)

Dépret, Thomas; Riquier, Jérémie; Piégay, Hervé

2017-10-01

In the second half of the 19th century, channelization of large multi-thread rivers such as the Rhine, the Danube, and the Rhône rivers induced artificial disconnection of most of their secondary channels. Compared to naturally abandoned channels, terrestrialization (i.e., the passage from the aquatic to the terrestrial stage, controlled by sediment deposits and/or lowering of the water level) patterns and rates of such artificially prematurely abandoned channels remain largely unknown. Moreover, factors controlling their evolutionary trajectories are complex owing to a set of pressures occurring throughout the 20th century within specific space-time windows. Through a case study of the Rhône River, this paper aims to assess and distinguish the effects of a set of potential controlling factors on abandoned channel terrestrialization dynamics and lifespan. We tested the influence of: (i) submersible embankments closing the entrance of abandoned channels, (ii) main channel degradation following its channelization or the water level lowering due to channel bypassing in the middle of the 20th century involving drastic water abstraction in these reaches, (iii) transverse dykes within the abandoned channels, (iv) the flooding regime of abandoned channels (i.e., frequency and magnitude of upstream connections producing lotic functioning), and (v) longitudinal variation in the suspended sediment concentration along the main channel. To this end, we studied 24 abandoned channels (16 artificially disconnected at their upstream end by submersible embankments and eight naturally disconnected by bar plug establishment) from the mid-19th to the beginning of the 20th century. Their terrestrialization rates were characterized through the reconstruction of their planimetric trajectories using historical maps and aerial photos. The results reveal a much longer lifespan of artificial abandoned channels compared to natural ones because of the truncation of the initial bedload infilling phase due to the artificial and imposed closing of their entrance. Moreover, terrestrialization occurred faster when water level lowering or channel degradation was greater. Surprisingly, terrestrialization rates were the highest in the most frequently connected artificial abandoned channels (i.e., channels with a high frequency of lotic functioning), probably in relation to the roughness induced by the presence of transversal dykes. Finally, it is difficult to rank all the factors tested because of their complex combinations, which can change in space and time.

An Artificial Channel Experiment for Purifying Drainage Water Containing Arsenic by Using Eleocharis acicularis

NASA Astrophysics Data System (ADS)

Okazaki, Kenji; Yamazaki, Shusaku; Kurahashi, Toshiyuki; Sakakibara, Masayuki

2017-06-01

This paper reports the results of an artificial channel experiment in which water containing arsenic was purified by using Eleocharis acicularis. The experiment was conducted to investigate the feasibility of phytoremediation by Eleocharis acicularis in civil engineering projects. In the experiment, 15 m2 of Eleocharis acicularis mats were laid in an artificial channel. Three sessions of artificial flow were implemented by leading 100.0 L of river water containing 0.234 mg/L of arsenic into the channel each time. The arsenic concentration of the leachate from the channel was analyzed. As the results of experiment, the arsenic concentrations of the leachate for the three sessions were 0.045 mg/L, 0.133 mg/L, and 0.249 mg/L. This shows that the arsenic concentration decreased during the first two sessions, whose flow totaled 200 L. The arsenic concentrations in the Eleocharis acicularis were 0.87 mg/kg, 1.01 mg/kg, and 4.16 mg/kg, which show that the plant absorbs arsenic. Moreover, it was found that the amount of sample water was reduced through evapotranspiration from the plant and the artificial channel.

Geomorphic and hydraulic assessment of the Bear River in and near Evanston, Wyoming

USGS Publications Warehouse

Smith, M.E.; Maderak, M.L.

1993-01-01

Geomorphic and hydraulic characteristics of the Bear River in and near Evanston, Wyoming, were assessed to assist planners in stabilizing the river channel. Present-day channel instability is the result of both human-made and natural factors. The primary factor is channelization of the river in Evanston, where several meander loops were cut off artificially during early development of the city. Other contributing factors include channel-width constrictions, bank stabilization, isolated bend cutoffs upstream from the city, and flooding in 1983 and 1984. A geomorphic analysis of bankfull-channel pattern, based on four aerial photographs taken during 1946-86, quantified geomorphic properties (reach sinuosity, bend sinuosity, bend radius of curvature, and bed length) that are characteristic of the study reach. The reach sinuosity of reach 2 (the channelized reach in Evanston) was 1.18 in 1986 and remained about the same throughout the period (1946-86). The reach sinuosity of reach 2 prior to channelization was substantially larger, about 2.3 as determined from maps prepared before 1946. Hydraulic analysis of the present-day channel (surveyed 1981-87) using a one-dimensional water-surface-profile computer model identified a bankfull discharge for the study reach of 3,600 cu ft/sec. A comparison of bankfull hydraulic properties for reaches 1, 2, and 3 indicated that the effects in reach 2 of channelization and channel-width constriction--increased slope, faster velocities, and greater hydraulic radii. The present-day channel slope in reach 2 is 0.00518 ft/ft, whereas a more stable slope would be between 0.00431 ft/ft (present-day slope in reach 1) and 0.00486 ft/ft (present-day slope in reach 3).

On-line Tool Wear Detection on DCMT070204 Carbide Tool Tip Based on Noise Cutting Audio Signal using Artificial Neural Network

NASA Astrophysics Data System (ADS)

Prasetyo, T.; Amar, S.; Arendra, A.; Zam Zami, M. K.

2018-01-01

This study develops an on-line detection system to predict the wear of DCMT070204 tool tip during the cutting process of the workpiece. The machine used in this research is CNC ProTurn 9000 to cut ST42 steel cylinder. The audio signal has been captured using the microphone placed in the tool post and recorded in Matlab. The signal is recorded at the sampling rate of 44.1 kHz, and the sampling size of 1024. The recorded signal is 110 data derived from the audio signal while cutting using a normal chisel and a worn chisel. And then perform signal feature extraction in the frequency domain using Fast Fourier Transform. Feature selection is done based on correlation analysis. And tool wear classification was performed using artificial neural networks with 33 input features selected. This artificial neural network is trained with back propagation method. Classification performance testing yields an accuracy of 74%.

Highly permeable artificial water channels that can self-assemble into two-dimensional arrays

PubMed Central

Shen, Yue-xiao; Si, Wen; Erbakan, Mustafa; Decker, Karl; De Zorzi, Rita; Saboe, Patrick O.; Kang, You Jung; Majd, Sheereen; Butler, Peter J.; Walz, Thomas; Aksimentiev, Aleksei; Hou, Jun-li; Kumar, Manish

2015-01-01

Bioinspired artificial water channels aim to combine the high permeability and selectivity of biological aquaporin (AQP) water channels with chemical stability. Here, we carefully characterized a class of artificial water channels, peptide-appended pillar[5]arenes (PAPs). The average single-channel osmotic water permeability for PAPs is 1.0(±0.3) × 10−14 cm3/s or 3.5(±1.0) × 108 water molecules per s, which is in the range of AQPs (3.4∼40.3 × 108 water molecules per s) and their current synthetic analogs, carbon nanotubes (CNTs, 9.0 × 108 water molecules per s). This permeability is an order of magnitude higher than first-generation artificial water channels (20 to ∼107 water molecules per s). Furthermore, within lipid bilayers, PAP channels can self-assemble into 2D arrays. Relevant to permeable membrane design, the pore density of PAP channel arrays (∼2.6 × 105 pores per μm2) is two orders of magnitude higher than that of CNT membranes (0.1∼2.5 × 103 pores per μm2). PAP channels thus combine the advantages of biological channels and CNTs and improve upon them through their relatively simple synthesis, chemical stability, and propensity to form arrays. PMID:26216964

Hardware Architecture and Cutting-Edge Assembly Process of a Tiny Curved Compound Eye

PubMed Central

Viollet, Stéphane; Godiot, Stéphanie; Leitel, Robert; Buss, Wolfgang; Breugnon, Patrick; Menouni, Mohsine; Juston, Raphaël; Expert, Fabien; Colonnier, Fabien; L'Eplattenier, Géraud; Brückner, Andreas; Kraze, Felix; Mallot, Hanspeter; Franceschini, Nicolas; Pericet-Camara, Ramon; Ruffier, Franck; Floreano, Dario

2014-01-01

The demand for bendable sensors increases constantly in the challenging field of soft and micro-scale robotics. We present here, in more detail, the flexible, functional, insect-inspired curved artificial compound eye (CurvACE) that was previously introduced in the Proceedings of the National Academy of Sciences (PNAS, 2013). This cylindrically-bent sensor with a large panoramic field-of-view of 180° × 60° composed of 630 artificial ommatidia weighs only 1.75 g, is extremely compact and power-lean (0.9 W), while it achieves unique visual motion sensing performance (1950 frames per second) in a five-decade range of illuminance. In particular, this paper details the innovative Very Large Scale Integration (VLSI) sensing layout, the accurate assembly fabrication process, the innovative, new fast read-out interface, as well as the auto-adaptive dynamic response of the CurvACE sensor. Starting from photodetectors and microoptics on wafer substrates and flexible printed circuit board, the complete assembly of CurvACE was performed in a planar configuration, ensuring high alignment accuracy and compatibility with state-of-the art assembling processes. The characteristics of the photodetector of one artificial ommatidium have been assessed in terms of their dynamic response to light steps. We also characterized the local auto-adaptability of CurvACE photodetectors in response to large illuminance changes: this feature will certainly be of great interest for future applications in real indoor and outdoor environments. PMID:25407908

Temporal evolution of liquid-assisted hard bio-tissue ablation with infrared pulsed lasers under a liquid environment

NASA Astrophysics Data System (ADS)

Chen, Faner; Li, Qiang; Hua, Mingxin; Zhan, Zhenlin; Xie, Shusen; Zhang, Xianzeng

2016-10-01

Liquid-assisted hard biotissue ablation with the pulsed lasers takes advantages in precision and compatibility than mechanical tools in traditional surgery. The objective of this study was to monitor the dynamic process of the cavitation bubble evolution induced by Ho:YAG laser under water and identify the opening time of channel formation between the fiber tip to the target tissue surface. A free-running Ho:YAG laser was used in the experiment. The wavelength was 2.1 μm with a pulse duration of 350 us and pulse energy varied from 500 mJ to 2000 mJ. The high-speed camera (PCO. dimax, Germany, PCO) applied to monitor the whole ablation process was setting at a frame rate of 52000 frames/s. The results showed that the cavitation bubble induced by laser energy experienced an oscillation process including occurrence, expansion, contraction and subsequent collapse. A channel connected the fiber tip and target tissue surface was formed during the dynamic process which allowed the following pulse energy transmitted through the channel with a relative low absorption and directly interacted with the target tissue. The beginning time of channel formation, as well as the duration of channel opening, as functions of incident laser energy were also presented. A micro-explosion was observed near the tissue surface during the bubble collapse, which may contribute to produce a clean cut, reduce the thermal injury and improve the morphology of ablation crater.

33 CFR 165.704 - Safety Zone; Tampa Bay, Florida.

Code of Federal Regulations, 2011 CFR

2011-07-01

... safety zone starts at Tampa Bay Cut “F” Channel from Lighted Buoys “3F” and “4F” and proceeds north ending at Gadsden Point Cut Lighted Buoys “3” and “4”. The safety zone starts again at Gadsden Point Cut Lighted Buoys “7” and “8” and proceeds north through Hillsborough Cut “C”, Port Sutton Entrance Channel...

Dimming LEDs with Phase-Cut Dimmers: The Specifier's Process for Maximizing Success

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

Miller, Naomi J.; Poplawski, Michael E.

2013-10-01

This report reviews how phase-cut dimmers work, how LEDs differ from the incandescent lamps that the dimmers were historically designed to control, and how these differences can lead to complications when trying to dim LEDs. Compatibility between a specific LED source and a specific phase-cut dimmer is often unknown and difficult to assess, and ensuring compatibility adds complexity to the design, specification, bidding, and construction observation phases for new buildings and major remodel projects. To maximize project success, this report provides both general guidance and step-by-step procedures for designing phase-controlled LED dimming on both new and existing projects, as wellmore » as real-world examples of how to use those procedures.« less

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

Chang, Hao, E-mail: hc000211@ohio.edu; Nanoscale and Quantum Phenomena Institute, Physics & Astronomy Department, Ohio University, Athens, Ohio 45701; Cummings, Marvin

High-speed beam choppers are a crucial part of time-resolved x-ray studies as well as a necessary component to enable elemental contrast in synchrotron x-ray scanning tunneling microscopy (SX-STM). However, many chopper systems are not capable of operation in vacuum, which restricts their application to x-ray studies with high photon energies, where air absorption does not present a significant problem. To overcome this limitation, we present a fully ultra-high vacuum (UHV) compatible chopper system capable of operating at variable chopping frequencies up to 4 kHz. The lightweight aluminum chopper disk is coated with Ti and Au films to provide the required beammore » attenuation for soft and hard x-rays with photon energies up to about 12 keV. The chopper is used for lock-in detection of x-ray enhanced signals in SX-STM.« less

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

Chang, Hao; Cummings, Marvin L.; Shirato, Nozomi

High-speed beam choppers are a crucial part of time-resolved x-ray studies as well as a necessary component to enable elemental contrast in synchrotron x-ray scanning tunneling microscopy (SX-STM). However, many chopper systems are not capable of operation in vacuum, which restricts their application to x-ray studies with high photon energies, where air absorption does not present a significant problem. To overcome this limitation, we present a fully ultra-high vacuum (UHV) compatible chopper system capable of operating at variable chopping frequencies up to 4 kHz. The lightweight aluminum chopper disk is coated with Ti and Au films to provide the requiredmore » beam attenuation for soft and hard x-rays with photon energies up to about 12 keV. The chopper is used for lock-in detection of x-ray enhanced signals in SX-STM.« less

The best of both worlds: automated CMP polishing of channel-cut monochromators

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

Kasman, Elina; Erdmann, Mark; Stoupin, Stanislav

2015-09-03

The use of a channel-cut monochromator is the most straightforward method to ensure that the two reflection surfaces maintain alignment between crystallographic planes without the need for complicated alignment mechanisms. Three basic characteristics that affect monochromator performance are: subsurface damage which contaminates spectral purity; surface roughness which reduces efficiency due to scattering; and surface figure error which imparts intensity structure and coherence distortion in the beam. Standard chemical-mechanical polishing processes and equipment are used when the diffracting surface is easily accessible, such as for single-bounce monochromators. Due to the inaccessibly of the surfaces inside a channel-cut monochromator for polishing, thesemore » optics are generally wet-etched for their final processing. This results in minimal subsurface damage, but very poor roughness and figure error. A new CMP channel polishing instrument design is presented which allows the internal diffracting surface quality of channel-cut crystals to approach that of conventional single-bounce monochromators« less

The physico-chemical properties and structural characteristics of artificial soil for cut slope restoration in Southwestern China

PubMed Central

Chen, Shunan; Ai, Xiaoyan; Dong, Tengyun; Li, Binbin; Luo, Ruihong; Ai, Yingwei; Chen, Zhaoqiong; Li, Chuanren

2016-01-01

Cut slopes are frequently generated by construction work in hilly areas, and artificial soil is often sprayed onto them to promote ecological rehabilitation. The artificial soil properties are very important for effective management of the slopes. This paper uses fractal and moment methods to characterize soil particle size distribution (PSD) and aggregates composition. The fractal dimension (D) showed linear relationships between clay, silt, and sand contents, with coefficients of determination from 0.843 to 0.875, suggesting that using of D to evaluate the PSD of artificial soils is reasonable. The bias (CS) and peak convex (CE) coefficients showed significant correlations with structure failure rate, moisture content, and total porosity, which validated the moment method to quantitatively describe soil structure. Railway slope (RS) soil has lower organic carbon and soil moisture, and higher pH than natural slope soil. Overall, RS exhibited poor soil structure and physicochemical properties, increasing the risk of soil erosion. Hence, more effective management measures should be adopted to promote the restoration of cut slopes. PMID:26883986

An Interactive Artificial Cutting Plane Method for Bicriterion Integer Programming Problems

DTIC Science & Technology

1992-08-01

AUTHOR(S) Diane Breivik Allen, 1st Lt 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER AFIT Student Attending...INTERACTIVE ARTIFICIAL CUTTING PLANE METHOD FOR BICRITERION INTEGER PROGRAMMING PROBLEMS By Diane Breivik Allen A Thesis Submitted to the Faculty of...ITfiSRA&1 DTIC TAB 0 Unannounced 0 Justirication By BY Diane Breivik Allen Distributlon/ Availability CQdes Avail and/or Dist Special Approved: DTI

Operational adaptability evaluation index system of pumped storage in UHV receiving-end grids

NASA Astrophysics Data System (ADS)

Yuan, Bo; Zong, Jin; Feng, Junshu

2017-01-01

Pumped storage is an effective solution to deal with the emergency reserve shortage, renewable energy accommodating and peak-shaving problems in ultra-high voltage (UHV) transmission receiving-end grids. However, governments and public opinion in China tend to evaluate the operational effectiveness of pumped storage using annual utilization hour, which may result in unreasonable and unnecessary dispatch of pumped storage. This paper built an operational adaptability evaluation index system for pumped storage in UHV-receiving end grids from three aspects: security insurance, peak-shaving and renewable energy accommodating, which can provide a comprehensive and objective way to evaluate the operational performance of a pumped storage station.

Note: Hollow cathode lamp with integral, high optical efficiency isolation valve: a modular vacuum ultraviolet source.

PubMed

Roberts, F Sloan; Anderson, Scott L

2013-12-01

The design and operating conditions of a hollow cathode discharge lamp for the generation of vacuum ultraviolet radiation, suitable for ultrahigh vacuum (UHV) application, are described in detail. The design is easily constructed, and modular, allowing it to be adapted to different experimental requirements. A thin isolation valve is built into one of the differential pumping stages, isolating the discharge section from the UHV section, both for vacuum safety and to allow lamp maintenance without venting the UHV chamber. The lamp has been used both for ultraviolet photoelectron spectroscopy of surfaces and as a "soft" photoionization source for gas-phase mass spectrometry.

Scalable Video Transmission Over Multi-Rate Multiple Access Channels

DTIC Science & Technology

2007-06-01

Rate - compatible punctured convolutional codes (RCPC codes ) and their ap- plications,” IEEE...source encoded using the MPEG-4 video codec. The source encoded bitstream is then channel encoded with Rate Compatible Punctured Convolutional (RCPC...Clark, and J. M. Geist, “ Punctured convolutional codes or rate (n-1)/n and simplified maximum likelihood decoding,” IEEE Transactions on

A 31-Channel MR Brain Array Coil Compatible with Positron Emission Tomography

PubMed Central

Sander, Christin Y.; Keil, Boris; Chonde, Daniel B.; Rosen, Bruce R.; Catana, Ciprian; Wald, Lawrence L.

2014-01-01

Purpose Simultaneous acquisition of MR and PET images requires the placement of the MR detection coil inside the PET detector ring where it absorbs and scatters photons. This constraint is the principal barrier to achieving optimum sensitivity on each modality. Here, we present a 31-channel PET-compatible brain array coil with reduced attenuation but improved MR sensitivity. Methods A series of component tests were performed to identify tradeoffs between PET and MR performance. Aspects studied include the remote positioning of preamplifiers, coax size, coil trace size/material, and plastic housing. We then maximized PET performance at minimal cost to MR sensitivity. The coil was evaluated for MR performance (SNR, g-factor) and PET attenuation. Results The coil design showed an improvement in attenuation by 190% (average) compared to conventional 32-channel arrays, and no loss in MR SNR. Moreover, the 31-channel coil displayed an SNR improvement of 230% (cortical ROI) compared to a PET-optimized 8-channel array with similar attenuation properties. Implementing attenuation correction of the 31-channel array successfully removed PET artifacts, which were comparable to those of the 8-channel array. Conclusion The design of the 31-channel PET-compatible coil enables higher sensitivity for PET/MR imaging, paving the way for novel applications in this hybrid-imaging domain. PMID:25046699

In Vitro Testing of an Implantable Wireless Telemetry System for Long-Term Electromyography Recordings in Large Animals.

PubMed

Kneisz, Lukas; Unger, Ewald; Lanmüller, Hermann; Mayr, Winfried

2015-10-01

Multichannel bio-signal recording in undisturbed in vivo conditions is a frequent demand in experimental work for development of methodology and associated equipment for functional electrical stimulation (FES) application, limb prosthesis, and diagnostic tools in contemporary rehabilitation efforts. Intramuscular electromyogram (EMG) recordings can provide comprehensive insight in complex interactions of agonistic and antagonistic muscles during movement tasks and in contrast act as reliable control signals for both neuroprosthesis and mechanical prosthesis. We fabricated a fully implantable device, which is capable of recording electromyography signals from inside a body and transmit these signals wirelessly to an external receiver. The developed analog front end uses only two electrodes per channel, provides a gain of 60 dB, and incorporates a band pass filter with lower cut-off frequency of 4 Hz and upper cut-off frequency of 480 Hz. The bidirectional wireless data link, which operates in the 2.4 GHz Industrial, Scientific and Medical band, is designed for transmission distances of 10 m using an application data rate of 1 kSps for each of the two channels. Performed in vitro tests with the devices coated in epoxy resin and inserted into a phantom with tissue-equivalent characteristics confirmed the functionality of our concept and the measurement results are consistent with those from preceding simulations. Copyright © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

A study on contraction of pneumatic artificial muscle (PAM) for load-lifting

NASA Astrophysics Data System (ADS)

Najmuddin, W. S. W. A.; Mustaffa, M. T.

2017-10-01

Pneumatic Artificial Muscles (PAMs) have been known for its wide application in various aspects of industrial automation and robotic equipments. Many advantages in terms of high power-to-volume ratio, high power-to-weight ratio, stick-slip-free operation and high degree of safety offer by PAM compare to traditional actuators. However, behind this benefits lie a limitation of significant compatibility of PAM mechanism which have to be considered so as to fully understand how the PAM works during load-lifting. In this study, the mesh suitability experiment and the effect of force load on PAM contraction experiment have been carried out. PAM is constructed and compatibility of bladder and the braided mesh to produce uniform expansion is investigated. Moreover, the first experimental result of finding compatibility is used to verify the contraction value under various loads.

Cutting roller

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

Best, G.; Weikert, N.B.

1984-05-29

A cutting roller for a mining machine, having a substantially conical closure member arranged to face the workings and a tubular body member which has a larger diameter at the end nearer the face working face than at the discharge end. The tubular member carries at least one cutting blade, and the closure member mounts at least one cutting blade; each blade is provided at its edge region with a plurality of bit holders for the attachment of cutter bits. The outer surface of the body member merges into the substantially conical closure member in a smooth, even curve, somore » that the outside diameter of the body member in the region of the working face is substantially greater than the diameter in the region of the discharge end of the cutting roller. The roller is provided with liquid distribution channels on each cutting blade, which channels are connected to a single liquid distribution ring channel in the region of the substantially conical closure member.« less

33 CFR 162.132 - Connecting waters from Lake Huron to Lake Erie; communications rules.

Code of Federal Regulations, 2011 CFR

2011-07-01

... monitor: (1) Channel 11 (156.55 mhz) between Lake Huron Cut Lighted Buoy 11 and Lake St. Clair Light; and (2) Channel 12 (156.60 mhz) between Lake St. Clair Light and Detroit River Light. (b) Radiotelephone... Cut Light “7” Lake Huron Cut Lighted Buoy “1” Report. Report St. Clair/Black River Junction Light...

Note: Hollow cathode lamp with integral, high optical efficiency isolation valve: A modular vacuum ultraviolet source

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

Sloan Roberts, F.; Anderson, Scott L.

2013-12-15

The design and operating conditions of a hollow cathode discharge lamp for the generation of vacuum ultraviolet radiation, suitable for ultrahigh vacuum (UHV) application, are described in detail. The design is easily constructed, and modular, allowing it to be adapted to different experimental requirements. A thin isolation valve is built into one of the differential pumping stages, isolating the discharge section from the UHV section, both for vacuum safety and to allow lamp maintenance without venting the UHV chamber. The lamp has been used both for ultraviolet photoelectron spectroscopy of surfaces and as a “soft” photoionization source for gas-phase massmore » spectrometry.« less

A compact ultra-clean system for deploying radioactive sources inside the KamLAND detector

NASA Astrophysics Data System (ADS)

Banks, T. I.; Freedman, S. J.; Wallig, J.; Ybarrolaza, N.; Gando, A.; Gando, Y.; Ikeda, H.; Inoue, K.; Kishimoto, Y.; Koga, M.; Mitsui, T.; Nakamura, K.; Shimizu, I.; Shirai, J.; Suzuki, A.; Takemoto, Y.; Tamae, K.; Ueshima, K.; Watanabe, H.; Xu, B. D.; Yoshida, H.; Yoshida, S.; Kozlov, A.; Grant, C.; Keefer, G.; Piepke, A.; Bloxham, T.; Fujikawa, B. K.; Han, K.; Ichimura, K.; Murayama, H.; O`Donnell, T.; Steiner, H. M.; Winslow, L. A.; Dwyer, D. A.; McKeown, R. D.; Zhang, C.; Berger, B. E.; Lane, C. E.; Maricic, J.; Miletic, T.; Batygov, M.; Learned, J. G.; Matsuno, S.; Sakai, M.; Horton-Smith, G. A.; Downum, K. E.; Gratta, G.; Efremenko, Y.; Perevozchikov, O.; Karwowski, H. J.; Markoff, D. M.; Tornow, W.; Heeger, K. M.; Detwiler, J. A.; Enomoto, S.; Decowski, M. P.

2015-01-01

We describe a compact, ultra-clean device used to deploy radioactive sources along the vertical axis of the KamLAND liquid-scintillator neutrino detector for purposes of calibration. The device worked by paying out and reeling in precise lengths of a hanging, small-gauge wire rope (cable); an assortment of interchangeable radioactive sources could be attached to a weight at the end of the cable. All components exposed to the radiopure liquid scintillator were made of chemically compatible UHV-cleaned materials, primarily stainless steel, in order to avoid contaminating or degrading the scintillator. To prevent radon intrusion, the apparatus was enclosed in a hermetically sealed housing inside a glove box, and both volumes were regularly flushed with purified nitrogen gas. An infrared camera attached to the side of the housing permitted real-time visual monitoring of the cable's motion, and the system was controlled via a graphical user interface.

A simple compact UHV and high magnetic field compatible inertial nanopositioner

NASA Astrophysics Data System (ADS)

Pang, Zongqiang; Li, Xiang; Xu, Lei; Rong, Zhou; Liu, Ruilan

2015-01-01

We present a novel simple piezoelectric nanopositioner which just has one piezoelectric scanner tube (PST) and one driving signal, using two short quartz rods and one BeCu spring which form a triangle to press the central shaft and can promise the nanopositioner's rigidity. Applying two pulse inverted voltage signals on the PST's outer and inner electrodes, respectively, according to the principle of piezoelectricity, the PST will elongate or contract suddenly while the central shaft will keep stationary for its inertance, so the central shaft will be sliding a distance relative to quartz rods and spring, and then withdraw the pulse voltages slowly, the central shaft will move upward or downward one step. The heavier of the central shaft, the better moving stability, so the nanopositioner has high output force. Due to its compactness and mechanical stability, it can be easily implanted into some extreme conditions, such as ultrahigh vacuum, ultralow temperature, and high magnetic field.

Office of Economic Adjustment | U.S. Department of Defense

Science.gov Websites

Reuse Compatible Use Defense Contractor Transitions Federal Assistance Coordination Mission Change contractor or manufacturer is making cuts or closing. Explore BRAC Icon Base Realignment and Closure A contact information. What We Do Base Closure Base Realignment Base Reuse Compatible Use Defense Contractor

UHV LT-STM system with Sample and Tip Exchange

NASA Astrophysics Data System (ADS)

Dreyer, Michael; Lee, Jonghee; Wang, Hui; Sullivan, Dan; Barker, Barry

2006-03-01

We developed and built a low temperature scanning tunneling microscope system with ultra high vacuum sample and tip preparation capabilities. The STM is mounted inside an UHV can which is submerged in a He bath cryostat. The cryostat is equipped with two superconducting magnets allowing a maximum in plane field of 2 T and a maximum out of plane field of 9 T. The two fields can be combined to a 1 T vector field. The vacuum can is connected to an UHV system at room temperature consisting of two chambers: One dedicated to transferring samples and tips to the STM, and the other chamber used for tip/sample preparation. It is equipped with two electron beam evaporators, an argon ion sputter gun as well as sample heaters. The whole system is supported by an optical table to decouple the STM from building vibrations. The system was successfully used to study standing electron waves on gold (111) as well as vortices on NbSe2. Details of the microscope, sample and tip handling system, as well as the UHV system will be presented.

50 CFR 648.146 - Special management zones.

Code of Federal Regulations, 2010 CFR

2010-10-01

... for an artificial reef, fish attraction device, or other modification of habitat for purposes of... that are not compatible with the intent of the artificial reef or fish attraction device or other... Magnuson-Stevens Act, and other applicable law. (5) The natural bottom in and surrounding potential SMZs...

A 31-channel MR brain array coil compatible with positron emission tomography.

PubMed

Sander, Christin Y; Keil, Boris; Chonde, Daniel B; Rosen, Bruce R; Catana, Ciprian; Wald, Lawrence L

2015-06-01

Simultaneous acquisition of MR and positron emission tomography (PET) images requires the placement of the MR detection coil inside the PET detector ring where it absorbs and scatters photons. This constraint is the principal barrier to achieving optimum sensitivity on each modality. Here, we present a 31-channel PET-compatible brain array coil with reduced attenuation but improved MR sensitivity. A series of component tests were performed to identify tradeoffs between PET and MR performance. Aspects studied include the remote positioning of preamplifiers, coax size, coil trace size/material, and plastic housing. We then maximized PET performance at minimal cost to MR sensitivity. The coil was evaluated for MR performance (signal to noise ratio [SNR], g-factor) and PET attenuation. The coil design showed an improvement in attenuation by 190% (average) compared with conventional 32-channel arrays, and no loss in MR SNR. Moreover, the 31-channel coil displayed an SNR improvement of 230% (cortical region of interest) compared with a PET-optimized 8-channel array with similar attenuation properties. Implementing attenuation correction of the 31-channel array successfully removed PET artifacts, which were comparable to those of the 8-channel array. The design of the 31-channel PET-compatible coil enables higher sensitivity for PET/MR imaging, paving the way for novel applications in this hybrid-imaging domain. © 2014 Wiley Periodicals, Inc.

Seeding and planting birch

Treesearch

John C. Bjorkbom

1969-01-01

Artificial regeneration of hardwoods does not have a very good reputation. Many of the early attempts to establish these species by seeding or planting resulted in failure. Then too, natural regeneration is usually adequate on cut over areas, so that there is little need for artificial regeneration on such areas. Nevertheless there are situations where artificial...

Atomic-Scale Structure of the Hematite α-Fe2O3(11̅02) “R-Cut” Surface

PubMed Central

2017-01-01

The α-Fe2O3(11̅02) surface (also known as the hematite r-cut or (012) surface) was studied using low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), scanning tunneling microscopy (STM), noncontact atomic force microscopy (nc-AFM), and ab initio density functional theory (DFT)+U calculations. Two surface structures are stable under ultrahigh vacuum (UHV) conditions; a stoichiometric (1 × 1) surface can be prepared by annealing at 450 °C in ≈10–6 mbar O2, and a reduced (2 × 1) reconstruction is formed by UHV annealing at 540 °C. The (1 × 1) surface is close to an ideal bulk termination, and the undercoordinated surface Fe atoms reduce the surface bandgap by ≈0.2 eV with respect to the bulk. The work function is measured to be 5.7 ± 0.2 eV, and the VBM is located 1.5 ± 0.1 eV below EF. The images obtained from the (2 × 1) reconstruction cannot be reconciled with previously proposed models, and a new “alternating trench” structure is proposed based on an ordered removal of lattice oxygen atoms. DFT+U calculations show that this surface is favored in reducing conditions and that 4-fold-coordinated Fe2+ cations at the surface introduce gap states approximately 1 eV below EF. The work function on the (2 × 1) termination is 5.4 ± 0.2 eV. PMID:29492182

The detection of dissolved gases in transformer oil by gas chromatography with helium ionization detector

NASA Astrophysics Data System (ADS)

Deng, Xian-qin; Fang, Hua; Li, Min-xian

2017-07-01

The GC-PDD with the technology of valve cutting and helium ionization detector was used to analyze the dissolved gases in ultra-high voltage(UHV) and extra-high voltage(EHV) transformer oil. The detection limit(DL) reached ppb grade, especially for the featuring gas—C2H2 and H2, whose DL could reach 5ppb and 11ppb respectively. The test reproducibility of the instrument was about 1% and the correlation coefficient of standard curve-r is greater or equal to 0.99, which showed obvious advantage compared with normal GC. In addition, the auxiliary gas of H2 was not used in this instrument, which completely improved the safety performance. Thus, the application of GC-PDD has significant meaning in warning potential malfunction inside the ultra-high voltage transformer in advance.

Bioelectronic Sensors and Devices

NASA Astrophysics Data System (ADS)

Reed, Mark

Nanoscale electronic devices have recently enabled the ability to controllably probe biological systems, from the molecular to the cellular level, opening up new applications and understanding of biological function and response. This talk reviews some of the advances in the field, ranging from diagnostic and therapeutic applications, to cellular manipulation and response, to the emulation of biological response. In diagnostics, integrated nanodevice biosensors compatible with CMOS technology have achieved unprecedented sensitivity, enabling a wide range of label-free biochemical and macromolecule sensing applications down to femtomolar concentrations. These systems have demonstrated integrated assays of biomarkers at clinically important concentrations for both diagnostics and as a quantitative tool for drug design and discovery. Cellular level response can also be observed, including immune response function and dynamics. Finally, the field is beginning to create devices that emulate function, and the demonstration of a solid state artificial ion channel will be discussed.

A Video Transmission System for Severely Degraded Channels

DTIC Science & Technology

2006-07-01

rate compatible punctured convolutional codes (RCPC) . By separating the SPIHT bitstream...June 2000. 149 [170] J. Hagenauer, Rate - compatible punctured convolutional codes (RCPC codes ) and their applications, IEEE Transactions on...Farvardin [160] used rate compatible convolutional codes . They noticed that for some transmission rates , one of their EEP schemes, which may

Isolation, identification, and characterization of novel arenaviruses, the etiological agents of boid inclusion body disease.

PubMed

Hetzel, Udo; Sironen, Tarja; Laurinmäki, Pasi; Liljeroos, Lassi; Patjas, Aino; Henttonen, Heikki; Vaheri, Antti; Artelt, Annette; Kipar, Anja; Butcher, Sarah J; Vapalahti, Olli; Hepojoki, Jussi

2013-10-01

Boid inclusion body disease (BIBD) is a progressive, usually fatal disease of constrictor snakes, characterized by cytoplasmic inclusion bodies (IB) in a wide range of cell types. To identify the causative agent of the disease, we established cell cultures from BIBD-positive and -negative boa constrictors. The IB phenotype was maintained in cultured cells of affected animals, and supernatants from these cultures caused the phenotype in cultures originating from BIBD-negative snakes. Viruses were purified from the supernatants by ultracentrifugation and subsequently identified as arenaviruses. Purified virus also induced the IB phenotype in naive cells, which fulfilled Koch's postulates in vitro. One isolate, tentatively designated University of Helsinki virus (UHV), was studied in depth. Sequencing confirmed that UHV is a novel arenavirus species that is distinct from other known arenaviruses including those recently identified in snakes with BIBD. The morphology of UHV was established by cryoelectron tomography and subtomographic averaging, revealing the trimeric arenavirus spike structure at 3.2-nm resolution. Immunofluorescence, immunohistochemistry, and immunoblotting with a polyclonal rabbit antiserum against UHV and reverse transcription-PCR (RT-PCR) revealed the presence of genetically diverse arenaviruses in a large cohort of snakes with BIBD, confirming the causative role of arenaviruses. Some snakes were also found to carry arenavirus antibodies. Furthermore, mammalian cells (Vero E6) were productively infected with UHV, demonstrating the potential of arenaviruses to cross species barriers. In conclusion, we propose the newly identified lineage of arenaviruses associated with BIBD as a novel taxonomic entity, boid inclusion body disease-associated arenaviruses (BIBDAV), in the family Arenaviridae.

Isolation, Identification, and Characterization of Novel Arenaviruses, the Etiological Agents of Boid Inclusion Body Disease

PubMed Central

Hetzel, Udo; Sironen, Tarja; Laurinmäki, Pasi; Liljeroos, Lassi; Patjas, Aino; Henttonen, Heikki; Vaheri, Antti; Artelt, Annette; Kipar, Anja; Butcher, Sarah J.; Vapalahti, Olli

2013-01-01

Boid inclusion body disease (BIBD) is a progressive, usually fatal disease of constrictor snakes, characterized by cytoplasmic inclusion bodies (IB) in a wide range of cell types. To identify the causative agent of the disease, we established cell cultures from BIBD-positive and -negative boa constrictors. The IB phenotype was maintained in cultured cells of affected animals, and supernatants from these cultures caused the phenotype in cultures originating from BIBD-negative snakes. Viruses were purified from the supernatants by ultracentrifugation and subsequently identified as arenaviruses. Purified virus also induced the IB phenotype in naive cells, which fulfilled Koch's postulates in vitro. One isolate, tentatively designated University of Helsinki virus (UHV), was studied in depth. Sequencing confirmed that UHV is a novel arenavirus species that is distinct from other known arenaviruses including those recently identified in snakes with BIBD. The morphology of UHV was established by cryoelectron tomography and subtomographic averaging, revealing the trimeric arenavirus spike structure at 3.2-nm resolution. Immunofluorescence, immunohistochemistry, and immunoblotting with a polyclonal rabbit antiserum against UHV and reverse transcription-PCR (RT-PCR) revealed the presence of genetically diverse arenaviruses in a large cohort of snakes with BIBD, confirming the causative role of arenaviruses. Some snakes were also found to carry arenavirus antibodies. Furthermore, mammalian cells (Vero E6) were productively infected with UHV, demonstrating the potential of arenaviruses to cross species barriers. In conclusion, we propose the newly identified lineage of arenaviruses associated with BIBD as a novel taxonomic entity, boid inclusion body disease-associated arenaviruses (BIBDAV), in the family Arenaviridae. PMID:23926354

Scanning Tunneling Microscopy Studies of Diamond Films and Optoelectronic Materials

NASA Technical Reports Server (NTRS)

Perez, Jose M.

1996-01-01

We present a summary of the research, citations of publications resulting from the research and abstracts of such publications. We have made no inventions in the performance of the work in this project. The main goals of the project were to set up a Chemical Vapor Deposition (CVD) diamond growth system attached to an UltraHigh Vacuum (UHV) atomic resolution Scanning Tunneling Microscopy (STM) system and carry out experiments aimed at studying the properties and growth of diamond films using atomic resolution UHV STM. We successfully achieved these goals. We observed, for the first time, the atomic structure of the surface of CVD grown epitaxial diamond (100) films using UHV STM. We studied the effects of atomic hydrogen on the CVD diamond growth process. We studied the electronic properties of the diamond (100) (2x1) surface, and the effect of alkali metal adsorbates such as Cs on the work function of this surface using UHV STM spectroscopy techniques. We also studied, using STM, new electronic materials such as carbon nanotubes and gold nanostructures. This work resulted in four publications in refereed scientific journals and five publications in refereed conference proceedings.

Oxygen accumulation on metal surfaces investigated by XPS, AES and LEIS, an issue for sputter depth profiling under UHV conditions

NASA Astrophysics Data System (ADS)

Steinberger, R.; Celedón, C. E.; Bruckner, B.; Roth, D.; Duchoslav, J.; Arndt, M.; Kürnsteiner, P.; Steck, T.; Faderl, J.; Riener, C. K.; Angeli, G.; Bauer, P.; Stifter, D.

2017-07-01

Depth profiling using surface sensitive analysis methods in combination with sputter ion etching is a common procedure for thorough material investigations, where clean surfaces free of any contamination are essential. Hence, surface analytic studies are mostly performed under ultra-high vacuum (UHV) conditions, but the cleanness of such UHV environments is usually overrated. Consequently, the current study highlights the in principle known impact of the residual gas on metal surfaces (Fe, Mg, Al, Cr and Zn) for various surface analytics methods, like X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and low-energy ion scattering (LEIS). The investigations with modern, state-of-the-art equipment showed different behaviors for the metal surfaces in UHV during acquisition: (i) no impact for Zn, even after long time, (ii) solely adsorption of oxygen for Fe, slight and slow changes for Cr and (iii) adsorption accompanied by oxide formation for Al and Mg. The efficiency of different counter measures was tested and the acquired knowledge was finally used for ZnMgAl coated steel to obtain accurate depth profiles, which exhibited before serious artifacts when data acquisition was performed in an inconsiderate way.

Transmission Technologies and Operational Characteristic Analysis of Hybrid UHV AC/DC Power Grids in China

NASA Astrophysics Data System (ADS)

Tian, Zhang; Yanfeng, Gong

2017-05-01

In order to solve the contradiction between demand and distribution range of primary energy resource, Ultra High Voltage (UHV) power grids should be developed rapidly to meet development of energy bases and accessing of large-scale renewable energy. This paper reviewed the latest research processes of AC/DC transmission technologies, summarized the characteristics of AC/DC power grids, concluded that China’s power grids certainly enter a new period of large -scale hybrid UHV AC/DC power grids and characteristics of “strong DC and weak AC” becomes increasingly pro minent; possible problems in operation of AC/DC power grids was discussed, and interaction or effect between AC/DC power grids was made an intensive study of; according to above problems in operation of power grids, preliminary scheme is summarized as fo llows: strengthening backbone structures, enhancing AC/DC transmission technologies, promoting protection measures of clean energ y accessing grids, and taking actions to solve stability problems of voltage and frequency etc. It’s valuable for making hybrid UHV AC/DC power grids adapt to operating mode of large power grids, thus guaranteeing security and stability of power system.

Full membrane spanning self-assembled monolayers as model systems for UHV-based studies of cell-penetrating peptides

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

Franz, Johannes; Graham, Daniel J.; Schmüser, Lars

2015-03-01

Biophysical studies of the interaction of peptides with model membranes provide a simple yet effective approach to understand the transport of peptides and peptide based drug carriers across the cell membrane. Therein, the authors discuss the use of self-assembled monolayers fabricated from the full membrane-spanning thiol (FMST) 3-((14-((4'-((5-methyl-1-phenyl-35-(phytanyl)oxy-6,9,12,15,18,21,24,27,30,33,37-undecaoxa-2,3-dithiahenpentacontan-51-yl)oxy)-[1,1'-biphenyl]-4-yl)oxy)tetradecyl)oxy)-2-(phytanyl)oxy glycerol for ultrahigh vacuum (UHV) based experiments. UHV-based methods such as electron spectroscopy and mass spectrometry can provide important information about how peptides bind and interact with membranes, especially with the hydrophobic core of a lipid bilayer. Moreover, near-edge x-ray absorption fine structure spectra and x-ray photoelectron spectroscopy (XPS) data showed thatmore » FMST forms UHV-stable and ordered films on gold. XPS and time of flight secondary ion mass spectrometry depth profiles indicated that a proline-rich amphipathic cell-penetrating peptide, known as sweet arrow peptide is located at the outer perimeter of the model membrane.« less

Distribution of contact loads over the flank-land of the cutter with a rounded cutting edge

NASA Astrophysics Data System (ADS)

Kozlov, V.; Gerasimov, A.; Kim, A.

2016-04-01

In this paper, contact conditions between a tool and a workpiece material for wear-simulating turning by a cutter with a sharp-cornered edge and with a rounded cutting edge are analysed. The results of the experimental study of specific contact load distribution over the artificial flank wear-land of the cutter in free orthogonal turning of the disk from titanium alloy (Ti6Al2Mo2Cr), ductile (63Cu) and brittle (57Cu1Al3Mn) brasses are described. Investigations were carried out by the method of ‘split cutter’ and by the method of the artificial flank-land of variable width. The experiments with a variable feed rate and a cutting speed show that in titanium alloy machining with a sharp-cornered cutting edge the highest normal contact load (σh max = 3400…2200 MPa) is observed immediately at the cutting edge, and the curve has a horizontal region with the length of 0.2… 0.6 mm. At a distance from the cutting edge, the value of specific normal contact load is dramatically reduced to 1100…500 MPa. The character of normal contact load for a rounded cutting edge is different -it is uniform, and its value is approximately 2 times smaller compared to machining with a sharp-cornered cutting edge. In author’s opinion it is connected with generation of a seizure zone in a chip formation region and explains the capacity of highly worn-out cutting tools for titanium alloys machining. The paper analyses the distribution of tangential contact loads over the flank land, which pattern differs considerably for machining with a sharp-cornered edge and with a rounded cutting edge. Abbreviation and symbols: m/s - meter per second (cutting speed v); mm/r - millimeter per revolution (feed rate f); MPa - mega Pascal (specific contact load as a stress σ or τ) hf - the width of the flank wear land (chamfer) of the cutting tool, flank wear land can be natural or artificial like the one in this paper [mm]; xh - distance from the cutting edge on the surface of the flank-land [mm]; σh - normal specific contact load on the flank land [MPa]; τh - tangential (shear) specific contact load on the flank land [MPa]; HSS - high speed steel (material of cutting tool); Py - radial component of cutting force [N]; Py r - radial component of cutting force on the rake face [N]; Pz - tangential component of cutting force [N]; γ - rake angle of the cutting tool [°] α - clearance angle of the sharp cutting tool [°] αh - clearance angle of the flank wear land [°] ρ - rounding off radius of the cutting edge [mm]; b - width of the machined disk [mm].

Extracellular domains play different roles in gap junction formation and docking compatibility.

PubMed

Bai, Donglin; Wang, Ao Hong

2014-02-15

GJ (gap junction) channels mediate direct intercellular communication and play an important role in many physiological processes. Six connexins oligomerize to form a hemichannel and two hemichannels dock together end-to-end to form a GJ channel. Connexin extracellular domains (E1 and E2) have been shown to be important for the docking, but the molecular mechanisms behind the docking and formation of GJ channels are not clear. Recent developments in atomic GJ structure and functional studies on a series of connexin mutants revealed that E1 and E2 are likely to play different roles in the docking. Non-covalent interactions at the docking interface, including hydrogen bonds, are predicted to form between interdocked extracellular domains. Protein sequence alignment analysis on the docking compatible/incompatible connexins indicate that the E1 domain is important for the formation of the GJ channel and the E2 domain is important in the docking compatibility in heterotypic channels. Interestingly, the hydrogen-bond forming or equivalent residues in both E1 and E2 domains are mutational hot spots for connexin-linked human diseases. Understanding the molecular mechanisms of GJ docking can assist us to develop novel strategies in rescuing the disease-linked connexin mutants.

Use of prototype two-channel endoscope with elevator enables larger lift-and-snare endoscopic mucosal resection in a porcine model

PubMed Central

Atkinson, Matthew; Chukwumah, Chike; Marks, Jeffrey; Chak, Amitabh

2014-01-01

Background: Flat and depressed lesions are becoming increasingly recognized in the esophagus, stomach, and colon. Various techniques have been described for endoscopic mucosal resection (EMR) of these lesions. Aims: To evaluate the efficacy of lift-grasp-cut EMR using a prototype dual-channel forward-viewing endoscope with an instrument elevator in one accessory channel (dual-channel elevator scope) as compared to standard dual-channel endoscopes. Methods: EMR was performed using a lift-grasp-cut technique on normal flat rectosigmoid or gastric mucosa in live porcine models after submucosal injection of 4 mL of saline using a dual-channel elevator scope or a standard dual-channel endoscope. With the dual-channel elevator scope, the elevator was used to attain further lifting of the mucosa. The primary endpoint was size of the EMR specimen and the secondary endpoint was number of complications. Results: Twelve experiments were performed (six gastric and six colonic). Mean specimen diameter was 2.27 cm with the dual-channel elevator scope and 1.34 cm with the dual-channel endoscope (P = 0.018). Two colonic perforations occurred with the dual-channel endoscope, vs no complications with the dual-channel elevator scope. Conclusions: The increased lift of the mucosal epithelium, through use of the dual-channel elevator scope, allows for larger EMR when using a lift-grasp-cut technique. Noting the thin nature of the porcine colonic wall, use of the elevator may also make this technique safer. PMID:24760237

Spread Spectrum Visual Sensor Network Resource Management Using an End-to-End Cross-Layer Design

DTIC Science & Technology

2011-02-01

Coding In this work, we use rate compatible punctured convolutional (RCPC) codes for channel coding [11]. Using RCPC codes al- lows us to utilize Viterbi’s...11] J. Hagenauer, “ Rate - compatible punctured convolutional codes (RCPC codes ) and their applications,” IEEE Trans. Commun., vol. 36, no. 4, pp. 389...source coding rate , a channel coding rate , and a power level to all nodes in the

Environmental management of a highly impacted, urbanized tropical estuary: rehabilitation and restoration

NASA Astrophysics Data System (ADS)

Thorhaug, A.

1980-03-01

The principles of the dynamics and interrelationships within the dominant subtropical and tropical Caribbean seagrass community have been studied previously before, during, and after impact. From these and scores of observations of damage and recovery patterns in Thalassia ecosystems, a sense of management recovery strategy has emerged. Artificial restoring of Thalassia testudinum seeds into areas cut off from stock (fruit, seeds) appeared feasible on a large scale after the Turkey Point (Biscayne Bay, Miami, Florida) restoration and test sampling throughout North Biscayne Bay. Two large-scale seeding attempts were made; after 11 months they compared favorably with Turkey Point specimens with regard to growth parameters, despite the turbidity and other persistent pollution. Thus, the possible areas in which Thalassia seed restoration can be used has increased to include estuaries of multiple impact still in various stages of recovery after physical and sewage pollution. This technique should be especially useful to “developing” nations where important nearshore fisheries nurseries based on Thalassia ecosystems have been heavily damaged and now lie barren. Man's impact on the estuary where seed restoration was attempted includes the following activities: 50% of the bay bottom directly dredged or filled (leaving much unconsolidated sediment); 50 million gallons of domestic waste dumped directly into a low flushing part of the bay for 20 years; seven major causeways transecting the bay, restricting circulation and flushing; two artificial inlets made into navigational channels; freshwater sheet flow drastically changed due to channelization by flood-control canals; urban runoff from a million people entering the bay. Most of the impacts have now abated; however, their long-term effects remain.

Development of speckle-free channel-cut crystal optics using plasma chemical vaporization machining for coherent x-ray applications.

PubMed

Hirano, Takashi; Osaka, Taito; Sano, Yasuhisa; Inubushi, Yuichi; Matsuyama, Satoshi; Tono, Kensuke; Ishikawa, Tetsuya; Yabashi, Makina; Yamauchi, Kazuto

2016-06-01

We have developed a method of fabricating speckle-free channel-cut crystal optics with plasma chemical vaporization machining, an etching method using atmospheric-pressure plasma, for coherent X-ray applications. We investigated the etching characteristics to silicon crystals and achieved a small surface roughness of less than 1 nm rms at a removal depth of >10 μm, which satisfies the requirements for eliminating subsurface damage while suppressing diffuse scattering from rough surfaces. We applied this method for fabricating channel-cut Si(220) crystals for a hard X-ray split-and-delay optical system and confirmed that the crystals provided speckle-free reflection profiles under coherent X-ray illumination.

Artificial phosphorylation sites modulate the activity of a voltage-gated potassium channel

NASA Astrophysics Data System (ADS)

Ariyaratne, Amila; Zocchi, Giovanni

2015-03-01

The KvAP potassium channel is representative of a family of voltage-gated ion channels where the membrane potential is sensed by a transmembrane helix containing several positively charged arginines. Previous work by Wang and Zocchi [A. Wang and G. Zocchi, PLoS ONE 6, e18598 (2011), 10.1371/journal.pone.0018598] showed how a negatively charged polyelectrolyte attached in proximity to the voltage sensing element can bias the opening probability of the channel. Here we introduce three phosphorylation sites at the same location and show that the response curve of the channel shifts by about 20 mV upon phosphorylation, while other characteristics such as the single-channel conductance are unaffected. In summary, we construct an artificial phosphorylation site which confers allosteric regulation to the channel.

Channelized subglacial drainage over a deformable bed

USGS Publications Warehouse

Walder, J.S.; Fowler, A.

1994-01-01

We develop theoretically a description of a possible subglacial drainage mechanism for glaciers and ice sheets moving over saturated, deformable till. The model is based on the plausible assumption that flow of water in a thin film at the ice-till interface is unstable to the formation of a channelized drainage system, and is restricted to the case in which meltwater cannot escape through the till to an underlying aquifer. In describing the physics of such channelized drainage, we have generalized and extended Rothlisberger's model of channels cut into basal ice to include "canals' cut into the till, paying particular attention to the role of sediment properties and the mechanics of sediment transport. We show that sediment-floored Rothlisberger (R) channels can exist for high effective pressures, and wide, shallow, ice-roofed canals cut into the till for low effective pressures. Canals should form a distributed, non-arborescent system, unlike R channels. Geologic evidence derived from land forms and deposits left by the Pleistocene ice sheets in North America and Europe is consistent with predictions of the model. -from Authors

Progressive transmission of images over fading channels using rate-compatible LDPC codes.

PubMed

Pan, Xiang; Banihashemi, Amir H; Cuhadar, Aysegul

2006-12-01

In this paper, we propose a combined source/channel coding scheme for transmission of images over fading channels. The proposed scheme employs rate-compatible low-density parity-check codes along with embedded image coders such as JPEG2000 and set partitioning in hierarchical trees (SPIHT). The assignment of channel coding rates to source packets is performed by a fast trellis-based algorithm. We examine the performance of the proposed scheme over correlated and uncorrelated Rayleigh flat-fading channels with and without side information. Simulation results for the expected peak signal-to-noise ratio of reconstructed images, which are within 1 dB of the capacity upper bound over a wide range of channel signal-to-noise ratios, show considerable improvement compared to existing results under similar conditions. We also study the sensitivity of the proposed scheme in the presence of channel estimation error at the transmitter and demonstrate that under most conditions our scheme is more robust compared to existing schemes.

Optimization of Straight Cylindrical Turning Using Artificial Bee Colony (ABC) Algorithm

NASA Astrophysics Data System (ADS)

Prasanth, Rajanampalli Seshasai Srinivasa; Hans Raj, Kandikonda

2017-04-01

Artificial bee colony (ABC) algorithm, that mimics the intelligent foraging behavior of honey bees, is increasingly gaining acceptance in the field of process optimization, as it is capable of handling nonlinearity, complexity and uncertainty. Straight cylindrical turning is a complex and nonlinear machining process which involves the selection of appropriate cutting parameters that affect the quality of the workpiece. This paper presents the estimation of optimal cutting parameters of the straight cylindrical turning process using the ABC algorithm. The ABC algorithm is first tested on four benchmark problems of numerical optimization and its performance is compared with genetic algorithm (GA) and ant colony optimization (ACO) algorithm. Results indicate that, the rate of convergence of ABC algorithm is better than GA and ACO. Then, the ABC algorithm is used to predict optimal cutting parameters such as cutting speed, feed rate, depth of cut and tool nose radius to achieve good surface finish. Results indicate that, the ABC algorithm estimated a comparable surface finish when compared with real coded genetic algorithm and differential evolution algorithm.

Use of tapered Pyrex capillary tubes to increase the mechanical stability of multiwall carbon nanotubes field emitters

NASA Astrophysics Data System (ADS)

Mousa, M. S.; Bani Ali, E. S.; Hagmann, M. J.

2018-02-01

In this study, NanocylTM NC 7000 Thin Multiwall Carbon Nanotubes (MWCNTs) were used with a high aspect ratio (>150) made by the process of catalytic chemical vapor deposition (CCVD). The field emitter tips were prepared by inserting these MWCT into fine glass capillary tubes that were pulled at high temperatures and then cut. Measurements were carried out under ultra-high vacuum (UHV) conditions with a base pressure of 10-9 mbar. The data show the effects of initial conditioning of MWCNT and hysteresis. Compression of the MWCNT by the capillary tubes appears to provide adequate mechanical support without requiring the use of a low-melting point electrically-conductive binder as has been used previously. Emission currents in excess of 1 μA were obtained so this technique shows promise as a reliable, stable, powerful electron source.

On Computations of Duct Acoustics with Near Cut-Off Frequency

NASA Technical Reports Server (NTRS)

Dong, Thomas Z.; Povinelli, Louis A.

1997-01-01

The cut-off is a unique feature associated with duct acoustics due to the presence of duct walls. A study of this cut-off effect on the computations of duct acoustics is performed in the present work. The results show that the computation of duct acoustic modes near cut-off requires higher numerical resolutions than others to avoid being numerically cut off. Duct acoustic problems in Category 2 are solved by the DRP finite difference scheme with the selective artificial damping method and results are presented and compared to reference solutions.

Artificial transmembrane ion channels from self-assembling peptide nanotubes

NASA Astrophysics Data System (ADS)

Ghadiri, M. Reza; Granja, Juan R.; Buehler, Lukas K.

1994-05-01

NATURALLY occurring membrane channels and pores are formed from a large family of diverse proteins, peptides and organic secon-dary metabolites whose vital biological functions include control of ion flow, signal transduction, molecular transport and produc-tion of cellular toxins. But despite the availability of a large amount of biochemical information about these molecules1, the design and synthesis of artificial systems that can mimic the bio-logical function of natural compounds remains a formidable task2-12. Here we present a simple strategy for the design of artifi-cial membrane ion channels based on a self-assembled cylindrical β-sheet peptide architecture13. Our systems-essentially stacks of peptide rings-display good channel-mediated ion-transport activ-ity with rates exceeding 107 ions s-1, rivalling the performance of many naturally occurring counterparts. Such molecular assemblies should find use in the design of novel cytotoxic agents, membrane transport vehicles and drug-delivery systems.

Spontaneous desorption and phase transitions of self-assembled alkanethiol and alicyclic thiol monolayers chemisorbed on Au(111) in ultrahigh vacuum at room temperature.

PubMed

Ito, Eisuke; Kang, Hungu; Lee, Dongjin; Park, Joon B; Hara, Masahiko; Noh, Jaegeun

2013-03-15

Scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) were used to examine the surface structure and adsorption conditions of hexanethiol (HT) and cyclohexanethiol (CHT) self-assembled monolayers (SAMs) on Au(111) as a function of storage period in ultrahigh vacuum (UHV) conditions of 3×10(-7) Pa at room temperature (RT). STM imaging revealed that after storage for 7 days, HT SAMs underwent phase transitions from c(4×2) phase to low coverage 4×√3 phase. This transition is due to a structural rearrangement of hexanethiolates that results from the spontaneous desorption of chemisorbed HT molecules on Au(111) surface. XPS measurements showed approximately 28% reduction in sulfur coverage, which indicates desorption of hexanethiolates from the surfaces. Contrary to HT SAMs, the structural order of CHT SAMs with (5×2√3)R35° phase completely disappeared after storage for 3 or 7 days. XPS results show desorption of more than 80% of the cyclohexanethiolates, even after storage for 3 days. We found that spontaneous desorption of CHT molecules on Au(111) in UHV at RT occurred quickly, whereas spontaneous desorption of HT molecules was much slower. Thermal desorption spectroscopy (TDS) results suggest CHT SAMs in UHV at RT can desorb more efficiently than HT SAMs due to formation of thiol desorption fragments that result from chemical reactions between surface hydrogen atoms and thiolates on Au(111) surfaces. This study clearly demonstrated that organic thiols chemisorbed on gold surfaces are desorbed spontaneously in UHV at RT and van der Waals interactions play an important role in determining the structural stability of thiolate SAMs in UHV. Copyright © 2012 Elsevier Inc. All rights reserved.

Genome-wide identification, classification and expression analysis in fungal-plant interactions of cutinase gene family and functional analysis of a putative ClCUT7 in Curvularia lunata.

PubMed

Liu, Tong; Hou, Jumei; Wang, Yuying; Jin, Yazhong; Borth, Wayne; Zhao, Fengzhou; Liu, Zheng; Hu, John; Zuo, Yuhu

2016-06-01

Cutinase is described as playing various roles in fungal-plant pathogen interactions, such as eliciting host-derived signals, fungal spore attachment and carbon acquisition during saprophytic growth. However, the characteristics of the cutinase genes, their expression in compatible interactions and their roles in pathogenesis have not been reported in Curvularia lunata, an important leaf spot pathogen of maize in China. Therefore, a cutinase gene family analysis could have profound significance. In this study, we identified 13 cutinase genes (ClCUT1 to ClCUT13) in the C. lunata genome. Multiple sequence alignment showed that most fungal cutinase proteins had one highly conserved GYSQG motif and a similar DxVCxG[ST]-[LIVMF](3)-x(3)H motif. Gene structure analyses of the cutinases revealed a complex intron-exon pattern with differences in the position and number of introns and exons. Based on phylogenetic relationship analysis, C. lunata cutinases and 78 known cutinase proteins from other fungi were classified into four groups with subgroups, but the C. lunata cutinases clustered in only three of the four groups. Motif analyses showed that each group of cutinases from C. lunata had a common motif. Real-time PCR indicated that transcript levels of the cutinase genes in a compatible interaction between pathogen and host had varied expression patterns. Interestingly, the transcript levels of ClCUT7 gradually increased during early pathogenesis with the most significant up-regulation at 3 h post-inoculation. When ClCUT7 was deleted, pathogenicity of the mutant decreased on unwounded maize (Zea mays) leaves. On wounded maize leaves, however, the mutant caused symptoms similar to the wild-type strain. Moreover, the ClCUT7 mutant had an approximately 10 % reduction in growth rate when cutin was the sole carbon source. In conclusion, we identified and characterized the cutinase family genes of C. lunata, analyzed their expression patterns in a compatible host-pathogen interaction, and explored the role of ClCUT7 in pathogenicity. This work will increase our understanding of cutinase genes in other fungal-plant pathogens.

Geological setting control of flood dynamics in lowland rivers (Poland).

PubMed

Wierzbicki, Grzegorz; Ostrowski, Piotr; Falkowski, Tomasz; Mazgajski, Michał

2018-04-27

We aim to answer a question: how does the geological setting affect flood dynamics in lowland alluvial rivers? The study area covers three river reaches: not trained, relatively large on the European scale, flowing in broad valleys cut in the landscape of old glacial plains. We focus on the locations where levees [both: a) natural or b) artificial] were breached during flood. In these locations we identify (1) the erosional traces of flood (crevasse channels) on the floodplain displayed on DEM derived from ALS LIDAR. In the main river channel, we perform drillings in order to measure the depth of the suballuvial surface and to locate (2) the protrusions of bedrock resistant to erosion. We juxtapose on one map: (1) the floodplain geomorphology with (2) the geological data from the river channel. The results from each of the three study reaches are presented on maps prepared in the same manner in order to enable a comparison of the regularities of fluvial processes written in (1) the landscape and driven by (2) the geological setting. These processes act in different river reaches: (a) not embanked and dominated by ice jam floods, (b) embanked and dominated by rainfall and ice jam floods. We also analyse hydrological data to present hydrodynamic descriptions of the flood. Our principal results indicate similarity of (1) distinctive erosional patterns and (2) specific geological features in all three study reaches. We draw the conclusion: protrusions of suballuvial bedrock control the flood dynamics in alluvial rivers. It happens in both types of rivers. In areas where the floodplain remains natural, the river inundates freely during every flood. In other areas the floodplain has been reclaimed by humans who constructed an artificial levee system, which protects the flood-prone area from inundation, until levee breach occurs. Copyright © 2018 Elsevier B.V. All rights reserved.

Channel electron multiplier compatibility with Viton and Apiezon-L vacuum grease

NASA Astrophysics Data System (ADS)

McComas, D. J.; Baldonado, J. R.; Bame, S. J.; Barraclough, B. L.

1987-12-01

Clean Viton and Viton coated with Apiezon-L vacuum grease were tested for their noncontaminating compatibility with channel electron multipliers (CEMs). The test setup and procedure were the same as those used previously in conjunction with CEM compatibility tests of certain epoxies, solder, and fluorocarbon polymer materials useful for construction of spaceflight sensors. While some CEM gain degradation was noted during exposure to Viton and Apiezon-L, the present tests indicate that, at least over instrument lifetimes of about 2 x 10 to the 12th counts, these materials should be suitable for (1) preflight space sensor testing systems, (2) hermetic seals for CEM-based space sensors, and (3) terrestrial CEM-based instrumentation.

Tools to Study Interfaces for Superconducting, Thermoelectric, and Magnetic Materials at the University of Houston

DTIC Science & Technology

2016-09-01

The MBE system, which grows crystalline thin films in ultrahigh vacuum (UHV) with precise control of thickness, composition, and morphology, will...used on our sputtering system to fabricate thin films with interfaces. - The electronic structures of these materials will be investigated using the...magnetization/transport measurements. The MBE system, which grows crystalline thin films in ultrahigh vacuum (UHV) with precise control of thickness, composition

n-Alcohols Inhibit Voltage-Gated Na+ Channels Expressed in Xenopus Oocytes

PubMed Central

Horishita, Takafumi; Harris, R. Adron

2008-01-01

Voltage-gated sodium channels are essential for the initiation and propagation of action potentials in excitable cells and are known as a target of local anesthetics. In addition, inhibition of sodium channels by volatile anesthetics has been proposed as a mechanism of general anesthesia. The n-alcohols produce anesthesia, and their potency increases with carbon number until a “cut-off” is reached. In this study, we examined effects of a range of n-alcohols on Nav1.2 subunits to determine the alcohol cut-off for this channel. We also studied the effect of a short-chain alcohol (ethanol) and a long-chain alcohol (octanol) on Nav1.2, Nav1.4, Nav1.6, and Nav1.8 subunits, and we investigated the effects of alcohol on channel kinetics. Ethanol and octanol inhibited sodium currents of all subunits, and the inhibition of the Nav1.2 channel by n-alcohols indicated a cut-off at nonanol. Ethanol and octanol produced open-channel block, which was more pronounced for Nav1.8 than for the other sodium channels. Inhibition of Nav1.2 was due to decreased activation and increased inactivation. These results suggest that sodium channels may have a hydrophobic binding site for n-alcohols and demonstrate the differences in the kinetic mechanisms of inhibition for n-alcohols and inhaled anesthetics. PMID:18434586

33 CFR 67.15-10 - Spoil banks, artificial islands, and dredged channels.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Spoil banks, artificial islands..., DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION AIDS TO NAVIGATION ON ARTIFICIAL ISLANDS AND FIXED STRUCTURES Miscellaneous Marking Requirements § 67.15-10 Spoil banks, artificial islands, and dredged...

33 CFR 67.15-10 - Spoil banks, artificial islands, and dredged channels.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Spoil banks, artificial islands..., DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION AIDS TO NAVIGATION ON ARTIFICIAL ISLANDS AND FIXED STRUCTURES Miscellaneous Marking Requirements § 67.15-10 Spoil banks, artificial islands, and dredged...

Application of Artificial Thunderstorm Cells for the Investigation of Lightning Initiation Problems between a Thundercloud and the Ground

NASA Astrophysics Data System (ADS)

Temnikov, A. G.; Chernensky, L. L.; Orlov, A. V.; Lysov, N. Y.; Zhuravkova, D. S.; Belova, O. S.; Gerastenok, T. K.

2017-12-01

The results of the experimental application of artificial thunderstorm cells of negative and positive polarities for the investigation of the lightning initiation problems between the thundercloud and the ground using model hydrometeor arrays are presented. Possible options of the initiation and development of a discharge between the charged cloud and the ground in the presence of model hydrometeors are established. It is experimentally shown that groups of large hydrometeors of various shapes significantly increase the probability of channel discharge initiation between the artificial thunderstorm cell and the ground, especially in the case of positive polarity of the cloud. The authors assume that large hail arrays in the thundercloud can initiate the preliminary breakdown stage in the lower part of the thundercloud or initiate and stimulate the propagation of positive lightning from its upper part. A significant effect of the shape of model hydrometeors and the way they are grouped on the processes of initiation and stimulation of the channel discharge propagation in the artificial thunderstorm cell of negative or positive polarity-ground gap is experimentally established. It is found that, in the case of negative polarity of a charged cloud, the group of conductive cylindrical hydrometeors connected by a dielectric string more effectively initiates the channel discharge between the artificial thunderstorm cell and the ground. In the case of positive polarity of the artificial thunderstorm cell, the best effect of the channel discharge initiation is achieved for model hydrometeors grouped together by the dielectric tape. The obtained results can be used in the development of the method for the directed artificial lightning initiation between the thundercloud and the ground.

A highly stable blood meal alternative for rearing Aedes and Anopheles mosquitoes.

PubMed

Baughman, Ted; Peterson, Chelsea; Ortega, Corrie; Preston, Sarah R; Paton, Christopher; Williams, Jessica; Guy, Amy; Omodei, Gavin; Johnson, Brian; Williams, Helen; O'Neill, Scott L; Ritchie, Scott A; Dobson, Stephen L; Madan, Damian

2017-12-01

We investigated alternatives to whole blood for blood feeding of mosquitoes with a focus on improved stability and compatibility with mass rearing programs. In contrast to whole blood, an artificial blood diet of ATP-supplemented plasma was effective in maintaining mosquito populations and was compatible with storage for extended periods refrigerated, frozen, and as a lyophilized powder. The plasma ATP diet supported rearing of both Anopheles and Aedes mosquitoes. It was also effective in rearing Wolbachia-infected Aedes mosquitoes, suggesting compatibility with vector control efforts.

Preparation of refractory cermet structures for lithium compatibility testing

NASA Technical Reports Server (NTRS)

Heestand, R. L.; Jones, R. A.; Wright, T. R.; Kizer, D. E.

1973-01-01

High-purity nitride and carbide cermets were synthesized for compatability testing in liquid lithium. A process was developed for the preparation of high-purity hafnium nitride powder, which was subsequently blended with tungsten powder or tantalum nitride and tungsten powders and fabricated into 3 in diameter billets by uniaxial hot pressing. Specimens were then cut from the billets for compatability testing. Similar processing techniques were applied to produce hafnium carbide and zirconium carbide cermets for use in the testing program. All billets produced were characterized with respect to chemistry, structure, density, and strength properties.

Conditions for the compatibility of channels in general probabilistic theory and their connection to steering and Bell nonlocality

NASA Astrophysics Data System (ADS)

Plávala, Martin

2017-11-01

We derive general conditions for the compatibility of channels in general probabilistic theory. We introduce formalism that allows us to easily formulate steering by channels and Bell nonlocality of channels as generalizations of the well-known concepts of steering by measurements and Bell nonlocality of measurements. The generalization does not follow the standard line of thinking stemming from the Einstein-Podolsky-Rosen paradox, but introduces steering and Bell nonlocality as entanglement-assisted incompatibility tests. We show that all of the proposed definitions are, in the special case of measurements, the same as the standard definitions, but not all of the known results for measurements generalize to channels. For example, we show that for quantum channels, steering is not a necessary condition for Bell nonlocality. We further investigate the introduced conditions and concepts in the special case of quantum theory and we provide many examples to demonstrate these concepts and their implications.

Physicochemical Quality and Chemical Safety of Chlorine as a Reconditioning Agent and Wash Water Disinfectant for Fresh-Cut Lettuce Washing

PubMed Central

Van Haute, Sam; Holvoet, Kevin; Uyttendaele, Mieke

2013-01-01

Chlorine was assessed as a reconditioning agent and wash water disinfectant in the fresh-cut produce industry. Artificial fresh-cut lettuce wash water, made from butterhead lettuce, was used for the experiments. In the reconditioning experiments, chlorine was added to artificial wash water inoculated with Escherichia coli O157 (6 log CFU/ml). Regression models were constructed based on the inactivation data and validated in actual wash water from leafy vegetable processing companies. The model that incorporated chlorine dose and chemical oxygen demand (COD) of the wash water accurately predicted inactivation. Listeria monocytogenes was more resistant to chlorine reconditioning in artificial wash water than Salmonella spp. and Escherichia coli O157. During the washing process with inoculated lettuce (4 log CFU/g), in the absence of chlorine, there was a rapid microbial buildup in the water that accumulated to 5.4 ± 0.4 log CFU/100 ml after 1 h. When maintaining a residual concentration of 1 mg/liter free chlorine, wash water contamination was maintained below 2.7, 2.5, and 2.5 log CFU/100 ml for tap water and artificial process water with COD values of 500 and 1,000 mg O2/liter, respectively. A model was developed to predict water contamination during the dynamic washing process. Only minor amounts of total trihalomethanes were formed in the water during reconditioning. Total trihalomethanes accumulated to larger amounts in the water during the wash water disinfection experiments and reached 124.5 ± 13.4 μg/liter after 1 h of execution of the washing process in water with a COD of 1,000 mg O2/liter. However, no total trihalomethanes were found on the fresh-cut lettuce after rinsing. PMID:23396332

Physicochemical quality and chemical safety of chlorine as a reconditioning agent and wash water disinfectant for fresh-cut lettuce washing.

PubMed

Van Haute, Sam; Sampers, Imca; Holvoet, Kevin; Uyttendaele, Mieke

2013-05-01

Chlorine was assessed as a reconditioning agent and wash water disinfectant in the fresh-cut produce industry. Artificial fresh-cut lettuce wash water, made from butterhead lettuce, was used for the experiments. In the reconditioning experiments, chlorine was added to artificial wash water inoculated with Escherichia coli O157 (6 log CFU/ml). Regression models were constructed based on the inactivation data and validated in actual wash water from leafy vegetable processing companies. The model that incorporated chlorine dose and chemical oxygen demand (COD) of the wash water accurately predicted inactivation. Listeria monocytogenes was more resistant to chlorine reconditioning in artificial wash water than Salmonella spp. and Escherichia coli O157. During the washing process with inoculated lettuce (4 log CFU/g), in the absence of chlorine, there was a rapid microbial buildup in the water that accumulated to 5.4 ± 0.4 log CFU/100 ml after 1 h. When maintaining a residual concentration of 1 mg/liter free chlorine, wash water contamination was maintained below 2.7, 2.5, and 2.5 log CFU/100 ml for tap water and artificial process water with COD values of 500 and 1,000 mg O2/liter, respectively. A model was developed to predict water contamination during the dynamic washing process. Only minor amounts of total trihalomethanes were formed in the water during reconditioning. Total trihalomethanes accumulated to larger amounts in the water during the wash water disinfection experiments and reached 124.5 ± 13.4 μg/liter after 1 h of execution of the washing process in water with a COD of 1,000 mg O2/liter. However, no total trihalomethanes were found on the fresh-cut lettuce after rinsing.

A compact ultra-clean system for deploying radioactive sources inside the KamLAND detector

DOE PAGES

Banks, T. I.; Freedman, S. J.; Wallig, J.; ...

2014-10-14

We describe a compact, ultra-clean device used to deploy radioactive sources along the vertical axis of the KamLAND liquid-scintillator neutrino detector for purposes of calibration. The device worked by paying out and reeling in precise lengths of a hanging, small-gauge wire rope (cable); an assortment of interchangeable radioactive sources could be attached to a weight at the end of the cable. All components exposed to the radiopure liquid scintillator were made of chemically compatible UHV-cleaned materials, primarily stainless steel, in order to avoid contaminating or degrading the scintillator. To prevent radon intrusion, the apparatus was enclosed in a hermetically sealedmore » housing inside a glove box, and both volumes were regularly flushed with purified nitrogen gas. Finally, an infrared camera attached to the side of the housing permitted real-time visual monitoring of the cable’s motion, and the system was controlled via a graphical user interface.« less

Addressing surface-induced loss and decoherence in superconducting quantum circuits

NASA Astrophysics Data System (ADS)

Fuhrer, Andreas; Mueller, Peter; Kuhlmann, Andreas; Filipp, Stefan; Deshpande, Veeresh; Drechsler, Ute

Many of the advances in coherence and fidelity of superconducting qubits have been made possible by clever engineering of the coupling to the environment and operation at noise-insensitive sweet spots. However, this leads to a compromise in experimental flexibility and device tunability, which can become inhibitive as the system size is scaled up. Material and interface related degrees of freedoms are harder to mitigate and are expected to become increasingly important in more complex systems. They impose limits both on coherence (flux-noise) and lifetimes (surface loss) of superconducting qubits. To study and eliminate these effects we have constructed a reusable UHV-compatible sample enclosure that enables us to perform various surface passivation steps before cooling superconducting devices to cryogenic temperatures. The enclosure can accommodate large chips with up to 18 microwave ports and can be vacuum sealed at pressures below 8e-10 mbar. We discuss its operation principle and present first measurement results of superconducting CPW resonators and qubit devices with and without prior surface treatments.

New XAFS Facility for In-Situ Measurements at Beamline C at HASYLAB

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

Rickers, K.; Drube, W.; Schulte-Schrepping, H.

2007-02-02

A XAFS-experiment allowing for in-situ experiments has been set up at DORIS bending magnet beamline C. For that purpose, a new double-crystal, UHV-compatible monochromator with fast scanning capability was designed. This fixed-exit monochromator uses two crystal sets on a common central rotation axis driven by an ex-vacuo goniometer. Bragg angles range from 5 deg. to 55.5 deg. resulting in a total energy range 2.3 - 43.4 keV using Si(111)/(311) crystal sets. Crystal pairs can be remotely selected by translating the vacuum chamber. Energy encoding is performed using an optical encoder system. The standard XAFS sample environment is set-up in vacuomore » and can be adapted for special sample environments. For in-situ experiments, the beamline is equipped with twelve gas lines. An exhaust line allows toxic/reactive gases to be handled. As an initial performance test of the instrument, Ti, Cr, Fe and Cu XAFS and Ce K-shell QEXAFS measurements were performed.« less

Quick-scanning x-ray absorption spectroscopy system with a servo-motor-driven channel-cut monochromator with a temporal resolution of 10 ms.

PubMed

Nonaka, T; Dohmae, K; Araki, T; Hayashi, Y; Hirose, Y; Uruga, T; Yamazaki, H; Mochizuki, T; Tanida, H; Goto, S

2012-08-01

We have developed a quick-scanning x-ray absorption fine structure (QXAFS) system and installed it at the recently constructed synchrotron radiation beamline BL33XU at the SPring-8. Rapid acquisition of high-quality QXAFS data was realized by combining a servo-motor-driven Si channel-cut monochromator with a tapered undulator. Two tandemly aligned monochromators with channel-cut Si(111) and Si(220) crystals covered energy ranges of 4.0-28.2 keV and 6.6-46.0 keV, respectively. The system allows the users to adjust instantly the energy ranges of scans, the starting angles of oscillations, and the frequencies. The channel-cut crystals are cooled with liquid nitrogen to enable them to withstand the high heat load from the undulator radiation. Deformation of the reflecting planes is reduced by clamping each crystal with two cooling blocks. Performance tests at the Cu K-edge demonstrated sufficiently high data quality for x-ray absorption near-edge structure and extended x-ray absorption fine-structure analyses with temporal resolutions of up to 10 and 25 ms, respectively.

In situ sputter cleaning of thin film metal substrates for UHV-TEM corrosion studies.

NASA Technical Reports Server (NTRS)

Heinemann, K.; Poppa, H.

1973-01-01

A prerequisite for conducting valid corrosion experiments by in situ electron microscopy techniques is not only the achievement of UHV background pressure conditions at the site of the specimen but also the ability to clean the surface of the thin metal substrate specimen before initiation of the corrosive interaction. A miniaturized simple ion gun has been constructed for this purpose. The gun is small enough to be incorporated into an UHV electron microscope specimen chamber with hot stage in such a way as to permit bombardment of the substrate specimen while observing it by transmission electron microscopy TEM. It is shown that the ion beam generated is confined well enough to cause a sputtering removal of substrate material at a rate of approximately 5-10 A/min and to prevent the sputter deposition of contaminating material from the specimen holder.

An advanced molecule-surface scattering instrument for study of vibrational energy transfer in gas-solid collisions.

PubMed

Ran, Qin; Matsiev, Daniel; Wodtke, Alec M; Auerbach, Daniel J

2007-10-01

We describe an advanced and highly sensitive instrument for quantum state-resolved molecule-surface energy transfer studies under ultrahigh vacuum (UHV) conditions. The apparatus includes a beam source chamber, two differential pumping chambers, and a UHV chamber for surface preparation, surface characterization, and molecular beam scattering. Pulsed and collimated supersonic molecular beams are generated by expanding target molecule mixtures through a home-built pulsed nozzle, and excited quantum state-selected molecules were prepared via tunable, narrow-band laser overtone pumping. Detection systems have been designed to measure specific vibrational-rotational state, time-of-flight, angular and velocity distributions of molecular beams coming to and scattered off the surface. Facilities are provided to clean and characterize the surface under UHV conditions. Initial experiments on the scattering of HCl(v = 0) from Au(111) show many advantages of this new instrument for fundamental studies of the energy transfer at the gas-surface interface.

Adaptive transmission based on multi-relay selection and rate-compatible LDPC codes

NASA Astrophysics Data System (ADS)

Su, Hualing; He, Yucheng; Zhou, Lin

2017-08-01

In order to adapt to the dynamical changeable channel condition and improve the transmissive reliability of the system, a cooperation system of rate-compatible low density parity check (RC-LDPC) codes combining with multi-relay selection protocol is proposed. In traditional relay selection protocol, only the channel state information (CSI) of source-relay and the CSI of relay-destination has been considered. The multi-relay selection protocol proposed by this paper takes the CSI between relays into extra account in order to obtain more chances of collabration. Additionally, the idea of hybrid automatic request retransmission (HARQ) and rate-compatible are introduced. Simulation results show that the transmissive reliability of the system can be significantly improved by the proposed protocol.

A Review of Flood-Related Storage and Remobilization of Heavy Metal Pollutants in River Systems.

PubMed

Ciszewski, Dariusz; Grygar, Tomáš Matys

Recently observed rapid climate changes have focused the attention of researchers and river managers on the possible effects of increased flooding frequency on the mobilization and redistribution of historical pollutants within some river systems. This text summarizes regularities in the flood-related transport, channel-to-floodplain transfer, and storage and remobilization of heavy metals, which are the most persistent environmental pollutants in river systems. Metal-dispersal processes are essentially much more variable in alluvia than in soils of non-inundated areas due to the effects of flood-sediment sorting and the mixing of pollutants with grains of different origins in a catchment, resulting in changes of one to two orders of magnitude in metal content over distances of centimetres. Furthermore, metal remobilization can be more intensive in alluvia than in soils as a result of bank erosion, prolonged floodplain inundation associated with reducing conditions alternating with oxygen-driven processes of dry periods and frequent water-table fluctuations, which affect the distribution of metals at low-lying strata. Moreover, metal storage and remobilization are controlled by river channelization, but their influence depends on the period and extent of the engineering works. Generally, artificial structures such as groynes, dams or cut-off channels performed before pollution periods favour the entrapment of polluted sediments, whereas the floodplains of lined river channels that adjust to new, post-channelization hydraulic conditions become a permanent sink for fine polluted sediments, which accumulate solely during overbank flows. Metal mobilization in such floodplains takes place only by slow leaching, and their sediments, which accrete at a moderate rate, are the best archives of the catchment pollution with heavy metals.

[Mechanical strength and mechano-compatibility of tissue-engineered bones].

PubMed

Tanaka, Shigeo

2016-01-01

Current artificial bones made of metals and ceramics may be replaced around a decade after implantation due to its low durability, which is brought on by a large difference from the host bone in mechanical properties, i.e., low mechano-compatibility. On the other hand, tissue engineering could be a solution with regeneration of bone tissues from stem cells in vitro. However, there are still some problems to realize exactly the same mechanical properties as those of real bone. This paper introduces the technical background of bone tissue engineering and discusses possible methods for installation of mechano-compatibility into a regenerative bone. At the end, future directions toward the realization of ideal mechano-compatible regenerative bone are proposed.

Prediction of Cutting Force in Turning Process-an Experimental Approach

NASA Astrophysics Data System (ADS)

Thangarasu, S. K.; Shankar, S.; Thomas, A. Tony; Sridhar, G.

2018-02-01

This Paper deals with a prediction of Cutting forces in a turning process. The turning process with advanced cutting tool has a several advantages over grinding such as short cycle time, process flexibility, compatible surface roughness, high material removal rate and less environment problems without the use of cutting fluid. In this a full bridge dynamometer has been used to measure the cutting forces over mild steel work piece and cemented carbide insert tool for different combination of cutting speed, feed rate and depth of cut. The experiments are planned based on taguchi design and measured cutting forces were compared with the predicted forces in order to validate the feasibility of the proposed design. The percentage contribution of each process parameter had been analyzed using Analysis of Variance (ANOVA). Both the experimental results taken from the lathe tool dynamometer and the designed full bridge dynamometer were analyzed using Taguchi design of experiment and Analysis of Variance.

Design of a -1 MV dc UHV power supply for ITER NBI

NASA Astrophysics Data System (ADS)

Watanabe, K.; Yamamoto, M.; Takemoto, J.; Yamashita, Y.; Dairaku, M.; Kashiwagi, M.; Taniguchi, M.; Tobari, H.; Umeda, N.; Sakamoto, K.; Inoue, T.

2009-05-01

Procurement of a dc -1 MV power supply system for the ITER neutral beam injector (NBI) is shared by Japan and the EU. The Japan Atomic Energy Agency as the Japan Domestic Agency (JADA) for ITER contributes to the procurement of dc -1 MV ultra-high voltage (UHV) components such as a dc -1 MV generator, a transmission line and a -1 MV insulating transformer for the ITER NBI power supply. The inverter frequency of 150 Hz in the -1 MV power supply and major circuit parameters have been proposed and adopted in the ITER NBI. The dc UHV insulation has been carefully designed since dc long pulse insulation is quite different from conventional ac insulation or dc short pulse systems. A multi-layer insulation structure of the transformer for a long pulse up to 3600 s has been designed with electric field simulation. Based on the simulation the overall dimensions of the dc UHV components have been finalized. A surge energy suppression system is also essential to protect the accelerator from electric breakdowns. The JADA contributes to provide an effective surge suppression system composed of core snubbers and resistors. Input energy into the accelerator from the power supply can be reduced to about 20 J, which satisfies the design criteria of 50 J in total in the case of breakdown at -1 MV.

Ultra high vacuum test setup for electron gun

NASA Astrophysics Data System (ADS)

Pandiyar, M. L.; Prasad, M.; Jain, S. K.; Kumar, R.; Hannurkar, P. R.

2008-05-01

Ultra High Vacuum (UHV) test setup for electron gun testing has been developed. The development of next generation light sources and accelerators require development of klystron as a radio frequency power source, and in turn electron gun. This UHV electron gun test setup can be used to test the electron guns ranging from high average current, quasi-continuous wave to high peak current, single pulse etc. An electron gun has been designed, fabricated, assembled and tested for insulation up to 80 kV under the programme to develop high power klystron for future accelerators. Further testing includes the electron emission parameters characterization of the cathode, as it determines the development of a reliable and efficient electron gun with high electron emission current and high life time as well. This needs a clean ultra high vacuum to study these parameters particularly at high emission current. The cathode emission current, work function and vapour pressure of cathode surface material at high temperature studies will further help in design and development of high power electron gun The UHV electron gun test setup consists of Turbo Molecular Pump (TMP), Sputter Ion Pump (SIP), pressure gauge, high voltage and cathode power supplies, current measurement device, solenoid magnet and its power supply, residual gas analyser etc. The ultimate vacuum less than 2×10-9 mbar was achieved. This paper describes the UHV test setup for electron gun testing.

Compatible immuno-NASBA LOC device for quantitative detection of waterborne pathogens: design and validation.

PubMed

Zhao, Xinyan; Dong, Tao; Yang, Zhaochu; Pires, Nuno; Høivik, Nils

2012-02-07

Waterborne pathogens usually pose a global threat to animals and human beings. There has been a growing demand for convenient and sensitive tools to detect the potential emerging pathogens in water. In this study, a lab-on-a-chip (LOC) device based on the real-time immuno-NASBA (immuno-nucleic acid sequence-based amplification) assay was designed, fabricated and verified. The disposable immuno-NASBA chip is modelled on a 96-well ELISA microplate, which contains 43 reaction chambers inside the bionic channel networks. All valves are designed outside the chip and are reusable. The sample and reagent solutions were pushed into each chamber in turn, which was controlled by the valve system. Notably, the immuno-NASBA chip is completely compatible with common microplate readers in a biological laboratory, and can distinguish multiple waterborne pathogens in water samples quantitatively and simultaneously. The performance of the LOC device was demonstrated by detecting the presence of a synthetic peptide, ACTH (adrenocorticotropic hormone) and two common waterborne pathogens, Escherichia coli (E. coli) and rotavirus, in artificial samples. The results indicated that the LOC device has the potential to quantify traces of waterborne pathogens at femtomolar levels with high specificity, although the detection process was still subject to some factors, such as ribonuclease (RNase) contamination and non-specific adsorption. As an ultra-sensitive tool to quantify waterborne pathogens, the LOC device can be used to monitor water quality in the drinking water system. Furthermore, a series of compatible high-throughput LOC devices for monitoring waterborne pathogens could be derived from this prototype with the same design idea, which may render the complicated immuno-NASBA assays convenient to common users without special training.

Compatibility Conditions of Structural Mechanics

NASA Technical Reports Server (NTRS)

Patnaik, Surya N.; Coroneos, Rula M.; Hopkins, Dale A.

1999-01-01

The theory of elasticity has camouflaged a deficiency in the compatibility formulation since 1860. In structures the ad hoc compatibility conditions through virtual "cuts" and closing "gaps" are not parallel to the strain formulation in elasticity. This deficiency in the compatibility conditions has prevented the development of a direct stress determination method in structures and in elasticity. We have addressed this deficiency and attempted to unify the theory of compatibility. This work has led to the development of the integrated force method for structures and the completed Beltrami-Michell formulation for elasticity. The improved accuracy observed in the solution of numerical examples by the integrated force method can be attributed to the compliance of the compatibility conditions. Using the compatibility conditions allows mapping of variables and facile movement among different structural analysis formulations. This paper reviews and illustrates the requirement of compatibility in structures and in elasticity. It also describes the generation of the conditions and quantifies the benefits of their use. The traditional analysis methods and available solutions (which have been obtained bypassing the missed conditions) should be verified for compliance of the compatibility conditions.

Bilayer Protograph Codes for Half-Duplex Relay Channels

NASA Technical Reports Server (NTRS)

Divsalar, Dariush; VanNguyen, Thuy; Nosratinia, Aria

2013-01-01

Direct to Earth return links are limited by the size and power of lander devices. A standard alternative is provided by a two-hops return link: a proximity link (from lander to orbiter relay) and a deep-space link (from orbiter relay to Earth). Although direct to Earth return links are limited by the size and power of lander devices, using an additional link and a proposed coding for relay channels, one can obtain a more reliable signal. Although significant progress has been made in the relay coding problem, existing codes must be painstakingly optimized to match to a single set of channel conditions, many of them do not offer easy encoding, and most of them do not have structured design. A high-performing LDPC (low-density parity-check) code for the relay channel addresses simultaneously two important issues: a code structure that allows low encoding complexity, and a flexible rate-compatible code that allows matching to various channel conditions. Most of the previous high-performance LDPC codes for the relay channel are tightly optimized for a given channel quality, and are not easily adapted without extensive re-optimization for various channel conditions. This code for the relay channel combines structured design and easy encoding with rate compatibility to allow adaptation to the three links involved in the relay channel, and furthermore offers very good performance. The proposed code is constructed by synthesizing a bilayer structure with a pro to graph. In addition to the contribution to relay encoding, an improved family of protograph codes was produced for the point-to-point AWGN (additive white Gaussian noise) channel whose high-rate members enjoy thresholds that are within 0.07 dB of capacity. These LDPC relay codes address three important issues in an integrative manner: low encoding complexity, modular structure allowing for easy design, and rate compatibility so that the code can be easily matched to a variety of channel conditions without extensive re-optimization. The main problem of half-duplex relay coding can be reduced to the simultaneous design of two codes at two rates and two SNRs (signal-to-noise ratios), such that one is a subset of the other. This problem can be addressed by forceful optimization, but a clever method of addressing this problem is via the bilayer lengthened (BL) LDPC structure. This method uses a bilayer Tanner graph to make the two codes while using a concept of "parity forwarding" with subsequent successive decoding that removes the need to directly address the issue of uneven SNRs among the symbols of a given codeword. This method is attractive in that it addresses some of the main issues in the design of relay codes, but it does not by itself give rise to highly structured codes with simple encoding, nor does it give rate-compatible codes. The main contribution of this work is to construct a class of codes that simultaneously possess a bilayer parity- forwarding mechanism, while also benefiting from the properties of protograph codes having an easy encoding, a modular design, and being a rate-compatible code.

Research of a smart cutting tool based on MEMS strain gauge

NASA Astrophysics Data System (ADS)

Zhao, Y.; Zhao, Y. L.; Shao, YW; Hu, T. J.; Zhang, Q.; Ge, X. H.

2018-03-01

Cutting force is an important factor that affects machining accuracy, cutting vibration and tool wear. Machining condition monitoring by cutting force measurement is a key technology for intelligent manufacture. Current cutting force sensors exist problems of large volume, complex structure and poor compatibility in practical application, for these problems, a smart cutting tool is proposed in this paper for cutting force measurement. Commercial MEMS (Micro-Electro-Mechanical System) strain gauges with high sensitivity and small size are adopted as transducing element of the smart tool, and a structure optimized cutting tool is fabricated for MEMS strain gauge bonding. Static calibration results show that the developed smart cutting tool is able to measure cutting forces in both X and Y directions, and the cross-interference error is within 3%. Its general accuracy is 3.35% and 3.27% in X and Y directions, and sensitivity is 0.1 mV/N, which is very suitable for measuring small cutting forces in high speed and precision machining. The smart cutting tool is portable and reliable for practical application in CNC machine tool.

Silicon-compatible high-hole-mobility transistor with an undoped germanium channel for low-power application

NASA Astrophysics Data System (ADS)

Cho, Seongjae; Man Kang, In; Rok Kim, Kyung; Park, Byung-Gook; Harris, James S.

2013-11-01

In this work, Ge-based high-hole-mobility transistor with Si compatibility is designed, and its performance is evaluated. A 2-dimensional hole gas is effectively constructed by a AlGaAs/Ge/Si heterojunction with a sufficiently large valence band offset. Moreover, an intrinsic Ge channel is exploited so that high hole mobility is preserved without dopant scattering. Effects of design parameters such as gate length, Ge channel thickness, and aluminum fraction in the barrier material on device characteristics are thoroughly investigated through device simulations. A high on-current above 30 μA/μm along with a low subthreshold swing was obtained from an optimized planar device for low-power applications.

The research of full automatic oil filtering control technology of high voltage insulating oil

NASA Astrophysics Data System (ADS)

Gong, Gangjun; Zhang, Tong; Yan, Guozeng; Zhang, Han; Chen, Zhimin; Su, Chang

2017-09-01

In this paper, the design scheme of automatic oil filter control system for transformer oil in UHV substation is summarized. The scheme specifically includes the typical double tank filter connection control method of the transformer oil of the UHV substation, which distinguishes the single port and the double port connection structure of the oil tank. Finally, the design scheme of the temperature sensor and respirator is given in detail, and the detailed evaluation and application scenarios are given for reference.

A case study of technology transfer: Rehabilitative engineering at Rancho Los Amigos Hospital. [prosthetic devices engineering

NASA Technical Reports Server (NTRS)

Hildred, W.

1973-01-01

The transfer of NASA technolgy to rehabilitative applications of artificial limbs is studied. Human factors engineering activities range from orthotic manipulators to tiny dc motors and transducers to detect and transmit voluntary control signals. It is found that bicarbon implant devices are suitable for medical equipment and artificial limbs because of their biological compatibility with human body fluids and tissues.

Interaction Structures for Narrow-Band Millimeter-Wave Communications TWTs.

DTIC Science & Technology

1981-04-01

comb would be cut from a single piece of copper, probably by a reliable but inexpensive technique such as electroerosion or "chemical milling". All...dimensional. These features would facilitate fabrication by chemical (photo-lithographic) or laser milling as well as by electroerosion with traveling...c, d) has also been implemented since this design should be more robust as well as compatible with electroerosion cutting using a traveling-wire

New Compatible Estimators for Survivor Growth and Ingrowth from Remeasured Horizontal Point Samples

Treesearch

Francis A. Roesch; Edwin J. Green; Charles T. Scott

1989-01-01

Forest volume growth between two measurements is often decomposed into the components of survivor growth (S), ingrowth(Z), mortality (M), and cut (C) (for example, Beers 1962 or Van Deusen et al. 1986). Net change between volumes at times 1 and 2 (V1 - V2) is then represented by the equation V,-V,=S+I-M-C. Two new compatible pairs of estimators for S and Z in this...

A diamond-based scanning probe spin sensor operating at low temperature in ultra-high vacuum

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

Schaefer-Nolte, E.; Wrachtrup, J.; 3rd Institute of Physics and Research Center SCoPE, University Stuttgart, 70569 Stuttgart

2014-01-15

We present the design and performance of an ultra-high vacuum (UHV) low temperature scanning probe microscope employing the nitrogen-vacancy color center in diamond as an ultrasensitive magnetic field sensor. Using this center as an atomic-size scanning probe has enabled imaging of nanoscale magnetic fields and single spins under ambient conditions. In this article we describe an experimental setup to operate this sensor in a cryogenic UHV environment. This will extend the applicability to a variety of molecular systems due to the enhanced target spin lifetimes at low temperature and the controlled sample preparation under UHV conditions. The instrument combines amore » tuning-fork based atomic force microscope (AFM) with a high numeric aperture confocal microscope and the facilities for application of radio-frequency (RF) fields for spin manipulation. We verify a sample temperature of <50 K even for strong laser and RF excitation and demonstrate magnetic resonance imaging with a magnetic AFM tip.« less

Design of an Operando Positron Annihilation Gamma Spectrometer (OPAGS)

NASA Astrophysics Data System (ADS)

Satyal, Suman; Shastry, Kartik; Kalaskar, Sushant; Lim, Larry; Joglekar, Vibek; Weiss, Alexander

2009-10-01

Surface properties measured under UHV conditions cannot be extended to surfaces interacting with gases under realistic pressures due to surface reconstruction and other strong perturbations of the surface. Many surface probing techniques used till now have required UHV conditions to avoid data loss due to scattering of outgoing particles. Here we describe the design of an Operando Positron Annihilation Gamma Spectrometer (OPAGS) currently under construction at the University of Texas at Arlington. The new system will be capable of obtaining surface and defect specific chemical and charge state information from surfaces under realistic pressures. Differential pumping will be used to maintain the sample in a gas environment while the rest of the beam is under UHV. The Elemental content of the surface interacting with the gas environment will be determined from the Doppler broadened gamma spectra. This system will also include a time of flight (TOF) positron annihilation induced Auger spectrometer (TOF-PAES) for use in combined annihilation induced Auger and annihilation gamma measurements made under low pressure conditions.

Benchtop fabrication of microfluidic systems based on curable polymers with improved solvent compatibility.

PubMed

Hashimoto, Michinao; Langer, Robert; Kohane, Daniel S

2013-01-21

This paper describes a general scheme to fabricate microchannels from curable polymers on a laboratory benchtop. Using the scheme described here, benchtop fabrication of SU-8 microfluidic systems was demonstrated for the first time, and their compatibility with organic solvents was demonstrated. The fabrication process has three major stages: 1) transferring patterns of microchannels to polymer films by molding, 2) releasing the patterned film and creating inlets and outlets for fluids, and 3) sealing two films together to create a closed channel system. Addition of a PDMS slab supporting the polymer film provided structural integrity during and after fabrication, allowing manipulation of the polymer films without fracturing or deformation. SU-8 channels fabricated according to this scheme exhibited solvent compatibility against continuous exposure to acetone and ethylacetate, which are incompatible with native PDMS. Using the SU-8 channels, continuous generation of droplets of ethylacetate, and templated synthesis of poly (lactic-co-glycolic acid) (PLGA) microparticles, both with stable size, were demonstrated continuously over 24 h, and at intervals over 75 days.

Artificial hairy surfaces with a nearly perfect hydrophobic response.

PubMed

Hsu, Shu-Hau; Sigmund, Wolfgang M

2010-02-02

A nearly perfect hydrophobic interface by dint of mimicking hairs of arthropods was achieved for the first time. These Gamma-shape artificial hairs were made via a membrane casting technique on polypropylene substrates. This extreme hydrophobicity merely arises from microstructure modification, and no further chemical treatments are needed. The ultralow adhesion to water droplets was evaluated through video assessment, and it is believed to be attributed to the mechanical response of the artificial hairs. The principle of this fabrication technique is accessible and is expected to be compatible with large-area fabrication of superhydrophobic interfaces.

Effects of E-64, a cysteine proteinase inhibitor, on cowpea weevil growth, development, and fecundity

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

Murdock, L.L.; Shade, R.E.; Pomeroy, M.A.

1988-06-01

E-64, a specific inhibitor of cysteine proteinases, was incorporated into artificial seeds at low levels (0.01-0.25% by weight). It prolonged developmental time and increased mortality of the larval cowpea weevil, Callosobruchus maculatus (F.), in direct proportion to its concentration in the artificial seeds. The fecundity of females emerging from the artificial seeds was significantly decreased by E-64 concentrations of 0.06% and higher. These observations are compatible with the hypothesis that the midgut cysteine proteinase in C. maculatus is essential for normal growth and development.

Artificial reefs and reef restoration in the Laurentian Great Lakes

USGS Publications Warehouse

McLean, Matthew W.; Roseman, Edward; Pritt, Jeremy J.; Kennedy, Gregory W.; Manny, Bruce A.

2015-01-01

We reviewed the published literature to provide an inventory of Laurentian Great Lakes artificial reef projects and their purposes. We also sought to characterize physical and biological monitoring for artificial reef projects in the Great Lakes and determine the success of artificial reefs in meeting project objectives. We found records of 6 artificial reefs in Lake Erie, 8 in Lake Michigan, 3 in Lakes Huron and Ontario, and 2 in Lake Superior. We found 9 reefs in Great Lakes connecting channels and 6 reefs in Great Lakes tributaries. Objectives of artificial reef creation have included reducing impacts of currents and waves, providing safe harbors, improving sport-fishing opportunities, and enhancing/restoring fish spawning habitats. Most reefs in the lakes themselves were incidental (not created purposely for fish habitat) or built to improve local sport fishing, whereas reefs in tributaries and connecting channels were more frequently built to benefit fish spawning. Levels of assessment of reef performance varied; but long-term monitoring was uncommon as was assessment of physical attributes. Artificial reefs were often successful at attracting recreational species and spawning fish; however, population-level benefits of artificial reefs are unclear. Stressors such as sedimentation and bio-fouling can limit the effectiveness of artificial reefs as spawning enhancement tools. Our investigation underscores the need to develop standard protocols for monitoring the biological and physical attributes of artificial structures. Further, long-term monitoring is needed to assess the benefits of artificial reefs to fish populations and inform future artificial reef projects.

Toxoplasma gondii seroprevalence and association with equine protozoal myeloencephalitis: A case-control study of Californian horses.

PubMed

James, K E; Smith, W A; Packham, A E; Conrad, P A; Pusterla, N

2017-06-01

While toxoplasmosis is not commonly considered a clinical disease of equines, previous seroprevalence studies have reported differing background rates of Toxoplasma gondii infection in horses globally. The objective of this study was to evaluate possible associations between T. gondii seroprevalence and clinical signs of equine protozoal myeloencephalitis (EPM) in horses. Using a case-control study design, 720 Californian horses with neurologic signs compatible with EPM were compared to healthy, non-neurologic horses for the presence of T. gondii antibodies (using indirect fluorescent antibody tests [IFAT]). Toxoplasma gondii seroprevalence among cases and controls was determined at standard serum cut-offs: 40, 80, 160, 320, and 640. At a T. gondii titre cut-off of 320, horses with clinical signs compatible with EPM had 3.55 times the odds of a seropositive test compared to those without clinical signs (P<0.01) when adjusted for covariates. When restricted to the autumn season and at the same titre cut-off, an EPM suspect horse had 6.4 times the odds of testing seropositive to T. gondii, compared to non-neurologic horses. The association between high T. gondii titres and clinical signs compatible with EPM is potentially reflective of toxoplasmosis in equines. Serologic testing of cerebrospinal fluid and isolation of T. gondii in EPM suspect cases should be considered. Future studies investigating the relationship between T. gondii and EPM are warranted. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydrocarbon-fuel/copper combustion chamber liner compatibility, corrosion prevention, and refurbishment

NASA Technical Reports Server (NTRS)

Rosenberg, S. D.; Gage, M. L.; Homer, G. D.; Franklin, J. E.

1991-01-01

An evaluation is made of combustion product/combustion chamber compatibility in the case of a LOX/liquid hydrocarbon booster engine based on copper-alloy thrust chamber which is regeneratively cooled by the fuel. It is found that sulfur impurities in the fuel are the primary causes of copper corrosion, through formation of Cu2S; sulfur levels as low as 1 ppm can result in sufficiently severe copper corrosion to degrade cooling channel performance. This corrosion can be completely eliminated, however, through the incorporation of an electrodeposited gold coating on the copper cooling-channel walls.

Improved Ion-Channel Biosensors

NASA Technical Reports Server (NTRS)

Nadeau, Jay; White, Victor; Dougherty, Dennis; Maurer, Joshua

2004-01-01

An effort is underway to develop improved biosensors of a type based on ion channels in biomimetic membranes. These sensors are microfabricated from silicon and other materials compatible with silicon. As described, these sensors offer a number of advantages over prior sensors of this type.

DDN (Defence Data Network) Protocol Implementations and Vendors Guide

DTIC Science & Technology

1988-08-01

Artificial Intelligence Laboratory Room NE43-723 545 Technology Square Cambridge, MA 02139 (617) 253-8843 S John Wroclawski, (JTW@AI.AJ.MIT.EDU...Massachusetts Institute of Technology Artificial Intelligence Laboratory Room NE43-743 545 Technology Square 0 Cambridge, MA 02139 (617) 253-7885 ORDERING...TCP/IP Network Software for PC-DOS Systems CPU: IBM-PC/XT/AT/compatible in conjunction with EXOS 205 Inteligent Ethernet Controller for PCbus 0/s

Voltage-driven reversible insertion into and leaving from a lipid bilayer: tuning transmembrane transport of artificial channels.

PubMed

Si, Wen; Li, Zhan-Ting; Hou, Jun-Li

2014-04-25

Three new artificial transmembrane channel molecules have been designed and synthesized by attaching positively charged Arg-incorporated tripeptide chains to pillar[5]arene. Fluorescent and patch-clamp experiments revealed that voltage can drive the molecules to insert into and leave from a lipid bilayer and thus switch on and off the transport of K(+) ions. One of the molecules was found to display antimicrobial activity toward Bacillus subtilis with half maximal inhibitory concentration (IC50 ) of 10 μM which is comparable to that of natural channel-forming peptide alamethicin. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mechanically activated artificial cell by using microfluidics

NASA Astrophysics Data System (ADS)

Ho, Kenneth K. Y.; Lee, Lap Man; Liu, Allen P.

2016-09-01

All living organisms sense mechanical forces. Engineering mechanosensitive artificial cell through bottom-up in vitro reconstitution offers a way to understand how mixtures of macromolecules assemble and organize into a complex system that responds to forces. We use stable double emulsion droplets (aqueous/oil/aqueous) to prototype mechanosensitive artificial cells. In order to demonstrate mechanosensation in artificial cells, we develop a novel microfluidic device that is capable of trapping double emulsions into designated chambers, followed by compression and aspiration in a parallel manner. The microfluidic device is fabricated using multilayer soft lithography technology, and consists of a control layer and a deformable flow channel. Deflections of the PDMS membrane above the main microfluidic flow channels and trapping chamber array are independently regulated pneumatically by two sets of integrated microfluidic valves. We successfully compress and aspirate the double emulsions, which result in transient increase and permanent decrease in oil thickness, respectively. Finally, we demonstrate the influx of calcium ions as a response of our mechanically activated artificial cell through thinning of oil. The development of a microfluidic device to mechanically activate artificial cells creates new opportunities in force-activated synthetic biology.

Performance of two oak species and three planting stocks on lands damaged by hurricane Katrina

Treesearch

John A. Conrad III; Andrew W. Ezell; Emily B. Schultz; John D. Hodges

2015-01-01

Hurricane Katrina had a devastating impact on bottomland hardwood forests in 2005. Artificial regeneration was considered the most appropriate method for reforesting these areas, but few studies have evaluated methods for artificially regenerating oaks on clear cut sites in the southern United States. First-year survival and growth of two oak species, live oak (Quercus...

Partial Cutting and Establishment of Artificial Nuttall Oak Regeneration in the Mississippi Alluvial Plain

Treesearch

Benjamin P. Ware; Emile S. Gardiner

2004-01-01

In the fall of 1998, we harvested a mixed bottomland hardwood stand in Sharkey County, MS, to establish two replicates of three residual stocking levels (0, 25, and 50 percent). We compared the various stand densities for suitability in establishment and growth of artificial oak regeneration. Following the overstory harvest, treatment plots received chain saw site...

[Ultrastructural observation of tendonization of artificial tendon 109HH in rabbit].

PubMed

Liu, L; Cao, Q; Xiao, H

1995-09-01

Ten New Zealand rabbits were divided into 5 groups at random. Calcaneal tendons were cut bilaterally, then atificial tendon 109HH was used to connect the two ends of the cut tendon. Ultrastructural changes of control group and experimental groups at 2, 6, 12, 28 weeks after section were observed. The results showed that fibroblast proliferated and a lot of ribosome and RER appeared in plasm during 2 approximately 6 weeks, indicating artificial tendon caused fibroblast proliferation. During this period, fibroblast over synthesized collagenous protein and the synthesis of collagenous fibers peaked. During 12-28 weeks, the number of fibroblasts and the synthesis of collagenous protein decreased. Finally, fibroblasts became inactive tendon cells. With the formation of new tendons, the artificial tendens were degradated and absorbed, and disappeared after 12 weeks. The new tendon fibers became thicker and had the correct direction through reconstruction. The structure and function of new tendons could be restored to be consistent with normal values.

High-voltage compatible, full-depleted CCD

DOEpatents

Holland, Stephen Edward

2007-09-18

A charge coupled device for detecting electromagnetic and particle radiation is described. The device includes a high-resistivity semiconductor substrate, buried channel regions, gate electrode circuitry, and amplifier circuitry. For good spatial resolution and high performance, especially when operated at high voltages with full or nearly full depletion of the substrate, the device can also include a guard ring positioned near channel regions, a biased channel stop, and a biased polysilicon electrode over the channel stop.

Spectral pattern recognition of controlled substances in street samples using artificial neural network system

NASA Astrophysics Data System (ADS)

Poryvkina, Larisa; Aleksejev, Valeri; Babichenko, Sergey M.; Ivkina, Tatjana

2011-04-01

The NarTest fluorescent technique is aimed at the detection of analyte of interest in street samples by recognition of its specific spectral patterns in 3-dimentional Spectral Fluorescent Signatures (SFS) measured with NTX2000 analyzer without chromatographic or other separation of controlled substances from a mixture with cutting agents. The illicit drugs have their own characteristic SFS features which can be used for detection and identification of narcotics, however typical street sample consists of a mixture with cutting agents: adulterants and diluents. Many of them interfere the spectral shape of SFS. The expert system based on Artificial Neural Networks (ANNs) has been developed and applied for such pattern recognition in SFS of street samples of illicit drugs.

Electrogates for stop-and-go control of liquid flow in microfluidics

NASA Astrophysics Data System (ADS)

Arango, Y.; Temiz, Y.; Gökçe, O.; Delamarche, E.

2018-04-01

Diagnostics based on microfluidic devices necessitate specific reagents, flow conditions, and kinetics for optimal performance. Such an optimization is often achieved using assay-specific microfluidic chip designs or systems with external liquid pumps. Here, we present "electrogates" for stop-and-go control of flow of liquids in capillary-driven microfluidic chips by combining liquid pinning and electrowetting. Electrogates are simple to fabricate and efficient: a sample pipetted to a microfluidic chip flows autonomously in 15-μm-deep hydrophilic channels until the liquid meniscus is pinned at the edge of a 1.5-μm-deep trench patterned at the bottom of a rectangular microchannel. The flow can then be resumed by applying a DC voltage between the liquid and the trench via integrated electrodes. Using a trench geometry with a semicircular shape, we show that retention times longer than 30 min are achieved for various aqueous solutions such as biological buffers, artificial urine, and human serum. We studied the activation voltage and activation delay of electrogates using a chip architecture having 6 independent flow paths and experimentally showed that the flow can be resumed in less than 1 s for voltages smaller than 10 V, making this technique compatible with low-power and portable microfluidic systems. Electrogates therefore can make capillary-driven microfluidic chips very versatile by adding flow control in microfluidic channels in a flexible manner.

Late Quaternary faulting along the Death Valley-Furnace Creek fault system, California and Nevada

USGS Publications Warehouse

Brogan, George E.; Kellogg, Karl; Slemmons, D. Burton; Terhune, Christina L.

1991-01-01

The Death Valley-Furnace Creek fault system, in California and Nevada, has a variety of impressive late Quaternary neotectonic features that record a long history of recurrent earthquake-induced faulting. Although no neotectonic features of unequivocal historical age are known, paleoseismic features from multiple late Quaternary events of surface faulting are well developed throughout the length of the system. Comparison of scarp heights to amount of horizontal offset of stream channels and the relationships of both scarps and channels to the ages of different geomorphic surfaces demonstrate that Quaternary faulting along the northwest-trending Furnace Creek fault zone is predominantly right lateral, whereas that along the north-trending Death Valley fault zone is predominantly normal. These observations are compatible with tectonic models of Death Valley as a northwest-trending pull-apart basin. The largest late Quaternary scarps along the Furnace Creek fault zone, with vertical separation of late Pleistocene surfaces of as much as 64 m (meters), are in Fish Lake Valley. Despite the predominance of normal faulting along the Death Valley fault zone, vertical offset of late Pleistocene surfaces along the Death Valley fault zone apparently does not exceed about 15 m. Evidence for four to six separate late Holocene faulting events along the Furnace Creek fault zone and three or more late Holocene events along the Death Valley fault zone are indicated by rupturing of Q1B (about 200-2,000 years old) geomorphic surfaces. Probably the youngest neotectonic feature observed along the Death Valley-Furnace Creek fault system, possibly historic in age, is vegetation lineaments in southernmost Fish Lake Valley. Near-historic faulting in Death Valley, within several kilometers south of Furnace Creek Ranch, is represented by (1) a 2,000-year-old lake shoreline that is cut by sinuous scarps, and (2) a system of young scarps with free-faceted faces (representing several faulting events) that cuts Q1B surfaces.

Mesocorticolimbic Connectivity and Volumetric Alterations in DCC Mutation Carriers.

PubMed

Vosberg, Daniel E; Zhang, Yu; Menegaux, Aurore; Chalupa, Amanda; Manitt, Colleen; Zehntner, Simone; Eng, Conrad; DeDuck, Kristina; Allard, Dominique; Durand, France; Dagher, Alain; Benkelfat, Chawki; Srour, Myriam; Joober, Ridha; Lepore, Franco; Rouleau, Guy; Théoret, Hugo; Bedell, Barry J; Flores, Cecilia; Leyton, Marco

2018-05-16

The axon guidance cue receptor DCC (deleted in colorectal cancer) plays a critical role in the organization of mesocorticolimbic pathways in rodents. To investigate whether this occurs in humans, we measured (1) anatomical connectivity between the substantia nigra/ventral tegmental area (SN/VTA) and forebrain targets, (2) striatal and cortical volumes, and (3) putatively associated traits and behaviors. To assess translatability, morphometric data were also collected in Dcc -haploinsufficient mice. The human volunteers were 20 DCC +/- mutation carriers, 16 DCC +/+ relatives, and 20 DCC +/+ unrelated healthy volunteers (UHVs; 28 females). The mice were 11 Dcc +/- and 16 wild-type C57BL/6J animals assessed during adolescence and adulthood. Compared with both control groups, the human DCC +/- carriers exhibited the following: (1) reduced anatomical connectivity from the SN/VTA to the ventral striatum [ DCC +/+ : p = 0.0005, r ( effect size ) = 0.60; UHV: p = 0.0029, r = 0.48] and ventral medial prefrontal cortex ( DCC +/+ : p = 0.0031, r = 0.53; UHV: p = 0.034, r = 0.35); (2) lower novelty-seeking scores ( DCC +/+ : p = 0.034, d = 0.82; UHV: p = 0.019, d = 0.84); and (3) reduced striatal volume ( DCC +/+ : p = 0.0009, d = 1.37; UHV: p = 0.0054, d = 0.93). Striatal volumetric reductions were also present in Dcc +/- mice, and these were seen during adolescence ( p = 0.0058, d = 1.09) and adulthood ( p = 0.003, d = 1.26). Together these findings provide the first evidence in humans that an axon guidance gene is involved in the formation of mesocorticolimbic circuitry and related behavioral traits, providing mechanisms through which DCC mutations might affect susceptibility to diverse neuropsychiatric disorders. SIGNIFICANCE STATEMENT Opportunities to study the effects of axon guidance molecules on human brain development have been rare. Here, the identification of a large four-generational family that carries a mutation to the axon guidance molecule receptor gene, DCC , enabled us to demonstrate effects on mesocorticolimbic anatomical connectivity, striatal volumes, and personality traits. Reductions in striatal volumes were replicated in DCC -haploinsufficient mice. Together, these processes might influence mesocorticolimbic function and susceptibility to diverse neuropsychiatric disorders. Copyright © 2018 the authors 0270-6474/18/384655-11$15.00/0.

MEMS compatible illumination and imaging micro-optical systems

NASA Astrophysics Data System (ADS)

Bräuer, A.; Dannberg, P.; Duparré, J.; Höfer, B.; Schreiber, P.; Scholles, M.

2007-01-01

The development of new MOEMS demands for cooperation between researchers in micromechanics, optoelectronics and microoptics at a very early state. Additionally, microoptical technologies being compatible with structured silicon have to be developed. The microoptical technologies used for two silicon based microsystems are described in the paper. First, a very small scanning laser projector with a volume of less than 2 cm 3, which operates with a directly modulated lasers collimated with a microlens, is shown. The laser radiation illuminates a 2D-MEMS scanning mirror. The optical design is optimized for high resolution (VGA). Thermomechanical stability is realized by design and using a structured ceramics motherboard. Secondly, an ultrathin CMOS-camera having an insect inspired imaging system has been realized. It is the first experimental realization of an artificial compound eye. Micro-optical design principles and technology is used. The overall thickness of the imaging system is only 320 μm, the diagonal field of view is 21°, and the f-number is 2.6. The monolithic device consists of an UV-replicated microlens array upon a thin silica substrate with a pinhole array in a metal layer on the back side. The pitch of the pinholes differs from that of the lens array to provide individual viewing angle for each channel. The imaging chip is directly glued to a CMOS sensor with adapted pitch. The whole camera is less than 1mm thick. New packaging methods for these systems are under development.

Producing Information for Corine Database by Using Classification Method: a Case Study of Sazlidere Basin, Istanbul

NASA Astrophysics Data System (ADS)

Sarıyılmaz, F. B.; Musaoğlu, N.; Uluğtekin, N.

2017-11-01

The Sazlidere Basin is located on the European side of Istanbul within the borders of Arnavutkoy and Basaksehir districts. The total area of the basin, which is largely located within the province of Arnavutkoy, is approximately 177 km2. The Sazlidere Basin is faced with intense urbanization pressures and land use / cover change due to the Northern Marmara Motorway, 3rd airport and Channel Istanbul Projects, which are planned to be realized in the Arnavutkoy region. Due to the mentioned projects, intense land use /cover changes occur in the basin. In this study, 2000 and 2012 dated LANDSAT images were supervised classified based on CORINE Land Cover first level to determine the land use/cover classes. As a result, four information classes were identified. These classes are water bodies, forest and semi-natural areas, agricultural areas and artificial surfaces. Accuracy analysis of the images were performed following the classification process. The supervised classified images that have the smallest mapping units 0.09 ha and 0.64 ha were generalized to be compatible with the CORINE Land Cover data. The image pixels have been rearranged by using the thematic pixel aggregation method as the smallest mapping unit is 25 ha. These results were compared with CORINE Land Cover 2000 and CORINE Land Cover 2012, which were obtained by digitizing land cover and land use classes on satellite images. It has been determined that the compared results are compatible with each other in terms of quality and quantity.

Variation of relative intensities between surface and bulk plasmon losses due to crystal orientations for aluminium in low energy electron reflection loss spectroscopy

NASA Astrophysics Data System (ADS)

Ichinokawa, T.; Le Gressus, C.; Mogami, A.; Pellerin, F.; Massignon, D.

The contrast change of secondary electron images due to the crystal orientations is observed by the ultra high vacuum scanning electron microscope (UHV-SEM) for crystal grains of clean surface of polycrystalline Al in the primary energy Ep of 200 eV to 5 KeV. The low energy electron loss spectra are measured by the cylindrical mirror analyzer. The relative intensity ratio between surface and bulk plasmon loss spectra was dependent on the crystal orientations. The SEM images taken by the surface and bulk plasmon signals at Ep = 230 eV show the inverse contrast depending on the grains. The inversion of the relative intensities between the surface and bulk plasmon losses is explained qualitatively by taking into account of variation of the penetration depth of the incident beam caused by the electron channeling.

Variation of relative intensities between surface and bulk plasmon losses due to crystal orientations for aluminium in low energy electron reflection loss spectroscopy

NASA Astrophysics Data System (ADS)

Ichinokawa, T.; Le Gressus, C.; Mogami, A.; Pellerin, F.; Massignon, D.

1981-10-01

The contrast change of secondary electron images due to the crystal orientations is observed by the ultra high vacuum scanning electron microscope (UHV-SEM) for crystal grains of clean surface of polycrystalline Al in the primary energy Ep of 200 eV to 5 keV. The low energy electron loss spectra are measured by the cylindrical mirror analyzer. The relative intensity ratio between surface and bulk plasmon loss spectra was dependent on the crystal orientations. The SEM images taken by the surface and bulk plasmon signals at Ep = 230 eV show the inverse contrast depending on the grains. The inversion of the relative intensities between the surface and bulk plasmon losses is explained qualitatively by taking into account of variation of the penetration depth of the incident beam caused by the electron channeling.

Set-up of an XAFS beamline for measurements between 2.4-8 keV at DORIS III

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

Welter, Edmund

2010-06-23

In this paper results from the commissioning phase and from first user experiments of a new EXAFS beamline at the DORIS III storage ring are presented. The bending magnet EXAFS beamline A1 underwent a complete rebuild and now covers the energy range 2.4-8 keV. A Ni-coated toroidal mirror, placed in a 2:1 focusing position and a plane mirror with one Ni coated stripe and one uncoated (SiO{sub 2}) stripe are used for effective higher harmonics suppression and focusing. The UHV-compatible fixed-exit Double Crystal Monochromator (DCM) is equipped with two Si(111) crystal pairs. The second crystal of one of the twomore » crystal pairs is tilted by 90 deg. around the surface normal to shift the position of glitches. It allows Bragg angles between 5 deg. and 55.5 deg. and continuous scans in quick-EXAFS mode. Test measurements during the commissioning phase proved the excellent performance of the monochromator and a high quality of the XAFS spectra over the entire working range.« less

Evaluation of Ti-Zr-V (NEG) Thin Films for their pumping speed and pumping Capacity

NASA Astrophysics Data System (ADS)

Bansod, Tripti; Sindal, B. K.; Kumar, K. V. A. N. P. S.; Shukla, S. K.

2012-11-01

Deposition of NEG thin films onto the interior walls of the vacuum chambers is an advanced technique to convert a vacuum chamber from a gas source to an effective pump. These films offer considerably large pumping speed for reactive gases like CO, H2 etc. A UHV compatible pumping speed measurement system was developed in-house to measure the pumping speed of NEG coated chambers. To inject the fixed quantity of CO and H2 gas in pumping speed measurement set-up a calibrated leak was also developed. Stainless steel chambers were sputter coated with thin film of Ti-Zr-V getter material using varied parameters for different compositions and thickness. Pumping capacity which is a function of sorbed gas quantities was also studied at various activation temperatures. In order to optimize the activation temperature for maximum pumping speed for CO and H2, pumping speeds were measured at room temperature after activation at different temperatures. The experimental system detail, pumping performance of the NEG film at various activation temperatures and RGA analysis are presented.

Laminated and infused Parafilm® - paper for paper-based analytical devices.

PubMed

Kim, Yong Shin; Yang, Yuanyuan; Henry, Charles S

2018-02-01

Numerous fabrication methods have been reported for microfluidic paper-based analytical devices (μPADs) using barrier materials ranging from photoresist to wax. While these methods have been used with wide success, consistently producing small, high-resolution features using materials and methods that are compatible with solvents and surfactants remains a challenge. Two new methods are presented here for generating μPADs with well-defined, high-resolution structures compatible with solvents and surfactant-containing solutions by partially or fully fusing paper with Parafilm® followed by cutting with a CO 2 laser cutter. Partial fusion leads to laminated paper ( l -paper) while the complete fusion results in infused paper ( i -paper). Patterned structures in l -paper were fabricated by selective removal of the paper but not the underlying Parafilm® using a benchtop CO 2 laser. Under optimized conditions, a gap as small as 137 ± 22 μm could be generated. Using this approach, a miniaturized paper 384-zone plate, consisting of circular detection elements with a diameter of 1.86 mm, was fabricated in 64 × 43 mm 2 area. Furthermore, these ablation-patterned substrates were confirmed to be compatible with surfactant solutions and common organic solvents (methanol, acetonitrile and dimethylformamide), which has been achieved by very few μPAD patterning techniques. Patterns in i -paper were created by completely cutting out zones of the i -paper and then fixing pre-cut paper into these openings similar to the strategy of fitting a jigsaw piece into a puzzle. Upon heating, unmodified paper was readily sealed into these openings due to partial reflow of the paraffin into the paper. This unique and simple bonding method was illustrated by two types of 3D μPADs, a push-on valve and a time-gated flow distributor, without adding adhesive layers. The free-standing jigsaw-patterned sheets showed good structural stability and solution compatibility, which provided a facile alternative method for fabricating complicated μPADs.

Earth Observations taken by Expedition 38 crewmember

NASA Image and Video Library

2014-02-21

ISS038-E-57806 (21 Feb. 2014) --- One of the Expedition 38 crew members aboard the International Space Station photographed this image of the Gulf of Mexico's Intracoastal Waterway in southern Texas. Represented in the photo are 18 kilometers (11.2 miles) of the overall 4800 kilometers-long (3000 miles) barge channel that lies on the protected inshore of the coastal islands of the southern and eastern USA, including coastal Texas. The small city of Port Aransas lies on a barrier island fully 18 kilometers (11.2 miles) seaward of the mainland and its sister city, Aransas Pass (lower left). This image shows parts of the waterway that are artificial, as in the straight sector leading into Corpus Christi Bay. Corpus Christi lies outside the lower margin of the image. Other sectors of the waterway are natural bays such as Aransas Bay. Jetties protect the inlet into the Gulf of Mexico (top right). Inlets at many points cut through the barrier islands to give shipping access to the Gulf of Mexico and the Atlantic Ocean.

In-situ ellipsometric studies of optical and surface properties of GaAs(100) at elevated temperatures

NASA Technical Reports Server (NTRS)

Yao, Huade; Snyder, Paul G.

1991-01-01

A rotating-polarizer ellipsometer was attached to an ultrahigh vacuum (UHV) chamber. A GaAs(100) sample was introduced into the UHV chamber and heated at anumber of fixed elevated temperatures, without arsenic overpressure. In-situ spectroscopic ellipsometric (SE) measurements were taken, through a pair of low-strain quartz windows, to monitor the surface changes and measure the pseudodielectric functions at elevated temperatures. Real-time data from GaAs surface covered with native oxide showed clearly the evolution of oxide desorption at approximately 580 C. In addition, surface degradation was found before and after the oxide desorption. An oxide free and smooth GaAs surface was obtained by depositing an arsenic protective coating onto a molecular beam epitaxy grown GaAs surface. The arsenic coating was evaporated immediately prior to SE measurements. A comparison showed that our room temperature data from this GaAs surface, measured in the UHV, are in good agreement with those in the literature obtained by wet-chemical etching. The surface also remained clean and smooth at higher temperatures, so that reliable temperature-dependent dielectric functions were obtained.

Electrospray deposition of organic molecules on bulk insulator surfaces.

PubMed

Hinaut, Antoine; Pawlak, Rémy; Meyer, Ernst; Glatzel, Thilo

2015-01-01

Large organic molecules are of important interest for organic-based devices such as hybrid photovoltaics or molecular electronics. Knowing their adsorption geometries and electronic structures allows to design and predict macroscopic device properties. Fundamental investigations in ultra-high vacuum (UHV) are thus mandatory to analyze and engineer processes in this prospects. With increasing size, complexity or chemical reactivity, depositing molecules by thermal evaporation becomes challenging. A recent way to deposit molecules in clean conditions is Electrospray Ionization (ESI). ESI keeps the possibility to work with large molecules, to introduce them in vacuum, and to deposit them on a large variety of surfaces. Here, ESI has been successfully applied to deposit triply fused porphyrin molecules on an insulating KBr(001) surface in UHV environment. Different deposition coverages have been obtained and characterization of the surface by in-situ atomic force microscopy working in the non-contact mode shows details of the molecular structures adsorbed on the surface. We show that UHV-ESI, can be performed on insulating surfaces in the sub-monolayer regime and to single molecules which opens the possibility to study a variety of complex molecules.

Surface friction of rock in terrestrial and simulated lunar environments

NASA Technical Reports Server (NTRS)

Roepke, W. W.; Peng, S. S.

1975-01-01

The conventional probe-on-the rotating-disk concept was used to determine the surface friction in mineral probe/specimen interfaces. Nine rocks or minerals and two stainless steels were tested in both new (NT) and same track (ST) tests under three different pressure environments-atmospheric, UHV, and dry nitrogen. Each environment was further subdivided into two testing conditions, that is, ambient and elevated (135 C) temperatures. In NT tests, friction was the lowest in an atmospheric pressure condition for all rock types and increased to the largest in UHV ambient condition except for pyroxene and stainless steel. Friction values measured in dry nitrogen ambient condition lie between the two extremes. Heating tends to increase friction in atmospheric and dry nitrogen environment but decreases in UHV environment with the exception of stainless steel, basalt, and pyroxene. In ST tests, friction was the lowest in the first run and increased in subsequent runs except for stainless steel where the reverse was true. The increases leveled off after a few runs ranging from the second to the seventh depending on rock types.

Ultrahigh Vacuum Scanning Tunneling Microscopy and Spectroscopy of Single-Walled Carbon Nanotubes Interfaced with Silicon Surfaces

NASA Astrophysics Data System (ADS)

Albrecht, Peter; Lyding, Joseph

2008-03-01

The UHV-STM was used to examine SWNTs directly interfaced with hydrogen-passivated Si(100). Dry contact transfer (DCT) [1] enabled the UHV deposition of SWNTs with minimal disruption of the atomically flat Si(100)-2x1:H surface. Isolated, rather than bundled, SWNTs could be routinely located for atomically resolved imaging, tunneling I-V spectroscopy [2], lateral manipulation [3], and proximal substrate modification. Weakly adsorbed SWNTs initially unstable in the presence of the rastered STM tip could be stabilized by depassivating the underlying H-Si(100) surface via UHV-STM electron-stimulated H desorption [4], which in the case of one chiral semiconducting SWNT also promoted the local alignment of the zigzag symmetry direction on the underside of the tube with the clean Si dimer rows [5]. The growing body of first-principles simulations of the SWNT/Si(100) system [6] was drawn upon in our interpretation of such local perturbations. [1] APL 83, 5029 (2003). [2] Nanotechnology 18, 095204 (2007). [3] Small 3, 146 (2007). [4] Nanotechnology 18, 125302 (2007). [5] Small 3, 1402 (2007). [6] JAP 100, 124304 (2006).

Operando Positron Annihilation Gamma Spectrometer (OPAGS)

NASA Astrophysics Data System (ADS)

Satyal, S.; Shastry, K.; Mukherjee, S.; Weiss, A. H.

2009-03-01

Surface properties measured under UHV conditions cannot be extended to surfaces interacting with gases under realistic pressures due to surface reconstruction and other strong perturbations of the surface. Surface probing techniques require UHV conditions to perform efficiently and avoid data loss due to scattering of outgoing particles. This poster describes the design of an Operando Positron Annihilation Gamma Spectrometer (OPAGS) currently under construction at the University of Texas at Arlington. The new system will be capable of obtaining surface and defect specific chemical and charge state information from surfaces under realistic pressures. Differential pumping will be used to maintain the sample in a gas environment while the rest of the beam is under UHV. Elemental content of the surface interacting with the gas environment will be determined from the Doppler broadened gamma spectra. This system will also include a time of flight (TOF) Auger spectrometer which correlates with the results of the Doppler measurements at lower pressures. By employing the unique capabilities of OPAGS together with those of the TOF PAES spectroscopy the charge transfer mechanisms at the surface in catalytic systems can be understood.

An Einzel lens apparatus for deposition of levitated graphene on a substrate in UHV

NASA Astrophysics Data System (ADS)

Coppock, Joyce; Nagornykh, Pavel; McAdams, Ian; Kane, Bruce

The goal of our research is to levitate a charged micron-scale graphene flake in an electrical AC quadrupole trap in ultra-high vacuum (UHV) in order to study its properties and dynamics while decoupled from any substrate. As a complement to the optical measurements that can be performed on the levitated flake, we are developing a method of depositing the same flake on a substrate, which can be removed from the system for further study using such probes as atomic force microscopy (AFM) and scanning tunneling microscopy (STM). As the flake is released from the trap and propelled toward the substrate, its trajectory will be controlled by an Einzel (electrostatic) lens to achieve accurate positioning on the substrate. This talk will discuss the design of the lens as well as particle tracing simulations to determine the proper lens voltage to focus the particle's trajectory. In the future, deposited graphene may be used to passivate H-terminated silicon. The method is expected to be generalizable to achieve deposition of 2D materials on surfaces in a clean UHV environment.

Harmonic voltage excess problem test and analysis in UHV and EHV grid particular operation mode

NASA Astrophysics Data System (ADS)

Lv, Zhenhua; Shi, Mingming; Fei, Juntao

2018-02-01

The test and analysis of the power quality of some 1000kV UHV transmission lines and 500kV EHV transmission lines is carried out. It is found that there is harmonic voltage excess problems when the power supply of the UHV and EHV voltage line is single-ended or single-loop, the problem basically disappeared after the operation mode change, different operating conditions, the harmonic current has not been greatly affected, indicating that the harmonic voltage changes mainly caused by the system harmonic impedance. With the analysis of MATLAB Simulink system model, it can be seen that there are specific harmonic voltage excess in the system under the specific operating mode, which results in serious distortion of the specific harmonic voltage. Since such phenomena are found in 500kV and 1000kV systems, it is suggested that the test evaluation work should be done under the typical mode of operation in 500kV, 1000kV Planning and construction process to prevent the occurrence of serious distortion and the regional harmonic current monitoring and suppression work should be done.

Alumina-supported sub-nanometer Pt 10 clusters: Amorphization and role of the support material in a highly active CO oxidation catalyst

DOE PAGES

Yin, Chunrong; Negreiros, Fabio R.; Barcaro, Giovanni; ...

2017-02-03

Catalytic CO oxidation is unveiled on size-selected Pt 10 clusters deposited on two very different ultrathin (≈0.5–0.7 nm thick) alumina films: (i) a highly ordered alumina obtained under ultra-high vacuum (UHV) by oxidation of the NiAl(110) surface and (ii) amorphous alumina obtained by atomic layer deposition (ALD) on a silicon chip that is a close model of real-world supports. Notably, when exposed to realistic reaction conditions, the Pt 10/UHV-alumina system undergoes a morphological transition in both the clusters and the substrate, and becomes closely akin to Pt 10/ALD-alumina, thus reconciling UHV-type surface-science and real-world experiments. The Pt 10 clusters, thoroughlymore » characterized via combined experimental techniques and theoretical analysis, exhibit among the highest CO oxidation activity per Pt atom reported for CO oxidation catalysts, due to the interplay of ultra-small size and support effects. Lastly, a coherent interdisciplinary picture then emerges for this catalytic system.« less

Ultrahigh-viscosity hydroxypropylmethylcellulose blunts postprandial glucose after a breakfast meal in women.

PubMed

Dow, Shireen; Pritchett, Kelly L; Hawk, Susan; Herrington, Stefanie J; Gee, David L

2012-04-01

To determine the effects of two water-soluble dietary fibers, ultrahigh-viscosity hydroxypropylmethylcellulose (UHV-HPMC, nonfermentable) and psyllium fiber (fermentable), on postprandial glucose and second meal effects. In a single-blind crossover design, 12 healthy adult subjects were given standardized, premeasured breakfast and lunch meals with either 4 g of the fiber supplements or a placebo. Blood glucose was measured with a continuous blood glucose monitoring system (DexCom Seven Plus, San Diego, CA). Subjects consuming UHV-HPMC had significantly (p < 0.05) lower blood glucose area under the curve (AUC) 2 hours after breakfast than those receiving a placebo. Subjects consuming psyllium also tended to have lower glucose levels than the placebo group. Peak glucose concentration following breakfast was significantly (p < 0.01) less with UHV-HPMC when compared with the placebo. No significant differences in AUC or peak glucose concentration between treatments following the second meal (lunch) were detected, suggesting no residual effect from the fiber supplements. Supplementation with viscous water-soluble fibers may be an effective means of reducing the glycemic response of a meal in healthy adults.

Performance interface document for the S-band diplexer for space users of NASA networks

NASA Technical Reports Server (NTRS)

Line, L. G.

1985-01-01

This report discusses the test results and interfacing information of the S-band diplexer development program supported by RTOP 310 funding. The program was implemented to reduce the S-band transponder noise figure by minimizing the receive channel insertion loss and to also provide Space Transportation System (STS) compatibility by providing 70-db rejection up to 16 GHz in the receive channel. This compatibility includes rejection of signals from the Shuttle S-band Data Link, the K-band Data Link, and the K-band Rendezvous Radar. The first of many projects to benefit from this accomplishment was the Earth Radiation Budget Satellite (ERBS).

High energy resolution, high angular acceptance crystal monochromator

DOEpatents

Alp, E.E.; Mooney, T.M.; Toellner, T.

1996-06-04

A 4-bounce dispersive crystal monochromator reduces the bandpass of synchrotron radiation to a 10-50 meV range without sacrificing angular acceptance. The monochromator includes the combination of an asymmetrical channel-cut single crystal of lower order reflection and a symmetrical channel-cut single crystal of higher order reflection in a nested geometric configuration. In the disclosed embodiment, a highly asymmetrically cut ({alpha}=20) outer silicon crystal (4 2 2) with low order reflection is combined with a symmetrically cut inner silicon crystal (10 6 4) with high order reflection to condition a hard x-ray component (5--30 keV) of synchrotron radiation down to the {micro}eV-neV level. Each of the crystals is coupled to the combination of a positioning inchworm and angle encoder via a respective rotation stage for accurate relative positioning of the crystals and precise energy tuning of the monochromator. 7 figs.

High energy resolution, high angular acceptance crystal monochromator

DOEpatents

Alp, Ercan E.; Mooney, Timothy M.; Toellner, Thomas

1996-06-04

A 4-bounce dispersive crystal monochromator reduces the bandpass of synchrotron radiation to a 10-50 meV range without sacrificing angular acceptance. The monochromator includes the combination of an asymmetrical channel-cut single crystal of lower order reflection and a symmetrical channel-cut single crystal of higher order reflection in a nested geometric configuration. In the disclosed embodiment, a highly asymmetrically cut (.alpha.=20) outer silicon crystal (4 2 2) with low order reflection is combined with a symmetrically cut inner silicon crystal (10 6 4) with high order reflection to condition a hard x-ray component (5-30 keV) of synchrotron radiation down to the .mu.eV-neV level. Each of the crystals is coupled to the combination of a positioning inchworm and angle encoder via a respective rotation stage for accurate relative positioning of the crystals and precise energy tuning of the monochromator.

Artificial intelligence guides system's best practices, cutting costs and improving services.

PubMed

1999-06-01

One for the history books. Clinical care improvement initiatives guided by a sophisticated artificial intelligence program have helped a major Virginia integrated health system make dramatic improvements in the cost and quality of its health care services. Find out how the technological innovation has earned Sentara Health System a place in the permanent collection of the Smithsonian's National Museum of American History.

Curriculum Assessment Using Artificial Neural Network and Support Vector Machine Modeling Approaches: A Case Study. IR Applications. Volume 29

ERIC Educational Resources Information Center

Chen, Chau-Kuang

2010-01-01

Artificial Neural Network (ANN) and Support Vector Machine (SVM) approaches have been on the cutting edge of science and technology for pattern recognition and data classification. In the ANN model, classification accuracy can be achieved by using the feed-forward of inputs, back-propagation of errors, and the adjustment of connection weights. In…

Digital data, composite video multiplexer and demultiplexer boards for an IBM PC/AT compatible computer

NASA Technical Reports Server (NTRS)

Smith, Dean Lance

1993-01-01

Work continued on the design of two IBM PC/AT compatible computer interface boards. The boards will permit digital data to be transmitted over a composite video channel from the Orbiter. One board combines data with a composite video signal. The other board strips the data from the video signal.

Development of a Laparoscopic Box Trainer Based on Open Source Hardware and Artificial Intelligence for Objective Assessment of Surgical Psychomotor Skills.

PubMed

Alonso-Silverio, Gustavo A; Pérez-Escamirosa, Fernando; Bruno-Sanchez, Raúl; Ortiz-Simon, José L; Muñoz-Guerrero, Roberto; Minor-Martinez, Arturo; Alarcón-Paredes, Antonio

2018-05-01

A trainer for online laparoscopic surgical skills assessment based on the performance of experts and nonexperts is presented. The system uses computer vision, augmented reality, and artificial intelligence algorithms, implemented into a Raspberry Pi board with Python programming language. Two training tasks were evaluated by the laparoscopic system: transferring and pattern cutting. Computer vision libraries were used to obtain the number of transferred points and simulated pattern cutting trace by means of tracking of the laparoscopic instrument. An artificial neural network (ANN) was trained to learn from experts and nonexperts' behavior for pattern cutting task, whereas the assessment of transferring task was performed using a preestablished threshold. Four expert surgeons in laparoscopic surgery, from hospital "Raymundo Abarca Alarcón," constituted the experienced class for the ANN. Sixteen trainees (10 medical students and 6 residents) without laparoscopic surgical skills and limited experience in minimal invasive techniques from School of Medicine at Universidad Autónoma de Guerrero constituted the nonexperienced class. Data from participants performing 5 daily repetitions for each task during 5 days were used to build the ANN. The participants tend to improve their learning curve and dexterity with this laparoscopic training system. The classifier shows mean accuracy and receiver operating characteristic curve of 90.98% and 0.93, respectively. Moreover, the ANN was able to evaluate the psychomotor skills of users into 2 classes: experienced or nonexperienced. We constructed and evaluated an affordable laparoscopic trainer system using computer vision, augmented reality, and an artificial intelligence algorithm. The proposed trainer has the potential to increase the self-confidence of trainees and to be applied to programs with limited resources.

33 CFR 165.704 - Safety Zone; Tampa Bay, Florida.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., Florida. (a) A floating safety zone is established consisting of an area 1000 yards fore and aft of a... ending at Gadsden Point Cut Lighted Buoys “3” and “4”. The safety zone starts again at Gadsden Point Cut... the marked channel at Tampa Bay Cut “K” buoy “11K” enroute to Rattlesnake, Tampa, FL, the floating...

Progressive video coding for noisy channels

NASA Astrophysics Data System (ADS)

Kim, Beong-Jo; Xiong, Zixiang; Pearlman, William A.

1998-10-01

We extend the work of Sherwood and Zeger to progressive video coding for noisy channels. By utilizing a 3D extension of the set partitioning in hierarchical trees (SPIHT) algorithm, we cascade the resulting 3D SPIHT video coder with a rate-compatible punctured convolutional channel coder for transmission of video over a binary symmetric channel. Progressive coding is achieved by increasing the target rate of the 3D embedded SPIHT video coder as the channel condition improves. The performance of our proposed coding system is acceptable at low transmission rate and bad channel conditions. Its low complexity makes it suitable for emerging applications such as video over wireless channels.

47 CFR 101.1421 - Coordination of adjacent area MVDDS stations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Multichannel Video Distribution and Data Service Rules for... compatible with adjacent and co-channel operations in the adjacent areas on all its frequencies; and (2... adjacent and co-channel operations in adjacent areas. (b) Harmful interference to public safety stations...

Nonlinear channel equalization for QAM signal constellation using artificial neural networks.

PubMed

Patra, J C; Pal, R N; Baliarsingh, R; Panda, G

1999-01-01

Application of artificial neural networks (ANN's) to adaptive channel equalization in a digital communication system with 4-QAM signal constellation is reported in this paper. A novel computationally efficient single layer functional link ANN (FLANN) is proposed for this purpose. This network has a simple structure in which the nonlinearity is introduced by functional expansion of the input pattern by trigonometric polynomials. Because of input pattern enhancement, the FLANN is capable of forming arbitrarily nonlinear decision boundaries and can perform complex pattern classification tasks. Considering channel equalization as a nonlinear classification problem, the FLANN has been utilized for nonlinear channel equalization. The performance of the FLANN is compared with two other ANN structures [a multilayer perceptron (MLP) and a polynomial perceptron network (PPN)] along with a conventional linear LMS-based equalizer for different linear and nonlinear channel models. The effect of eigenvalue ratio (EVR) of input correlation matrix on the equalizer performance has been studied. The comparison of computational complexity involved for the three ANN structures is also provided.

Influence of cutting data on surface quality when machining 17-4 PH stainless steel

NASA Astrophysics Data System (ADS)

Popovici, T. D.; Dijmărescu, M. R.

2017-08-01

The aim of the research presented in this paper is to analyse the cutting data influence upon surface quality for 17-4 PH stainless steel milling machining. The cutting regime parameters considered for the experiments were established using cutting regimes from experimental researches or from industrial conditions as basis, within the recommended ranges. The experimental program structure was determined by taking into account compatibility and orthogonality conditions, minimal use of material and labour. The machined surface roughness was determined by measuring the Ra roughness parameter, followed by surface profile registration in the form of graphics which were saved on a computer with MarSurf PS1Explorer software. Based on Ra roughness parameter, maximum values were extracted from these graphics and the influence charts of the cutting regime parameters upon surface roughness were traced using Microsoft Excel software. After a thorough analysis of the resulting data, relevant conclusions were drawn, presenting the interdependence between the surface roughness of the machined 17-4 PH samples and the cutting data variation.

Different spatial distributions of sodium channels in the slowly and rapidly adapting stretch receptor neuron of the crayfish.

PubMed

Lin, J H; Rydqvist, B

1999-06-05

Inward Na+ currents were studied, using a two-microelectrode intracellular voltage-clamp technique, in the slowly adapting (SA) and rapidly adapting (RA) stretch receptor neurons of the crayfish after the axons were cut at different distances from the soma. In the SA neuron, inward Na+ currents were recorded in the soma even when the axon was cut as close as 100 microm from the center of the soma, indicating the presence of Na+ channels in these parts. Also, two populations of Na+ channels seem to exist in the SA neuron. In the RA neuron, only minute Na+ currents were observed if the axon was shorter than 250 microm. The results strongly indicate that the voltage-gated Na+ channels in the SA and RA neurons have different distributions and that the difference in the spatial distribution of Na+ channel types may be important for the difference in firing properties in the two types of neurons. Copyright 1999 Elsevier Science B.V.

Perturbative Quantum Gauge Theories on Manifolds with Boundary

NASA Astrophysics Data System (ADS)

Cattaneo, Alberto S.; Mnev, Pavel; Reshetikhin, Nicolai

2018-01-01

This paper introduces a general perturbative quantization scheme for gauge theories on manifolds with boundary, compatible with cutting and gluing, in the cohomological symplectic (BV-BFV) formalism. Explicit examples, like abelian BF theory and its perturbations, including nontopological ones, are presented.

The fabrication of a double-layer atom chip with through silicon vias for an ultra-high-vacuum cell

NASA Astrophysics Data System (ADS)

Chuang, Ho-Chiao; Lin, Yun-Siang; Lin, Yu-Hsin; Huang, Chi-Sheng

2014-04-01

This study presents a double-layer atom chip that provides users with increased diversity in the design of the wire patterns and flexibility in the design of the magnetic field. It is more convenient for use in atomic physics experiments. A negative photoresist, SU-8, was used as the insulating layer between the upper and bottom copper wires. The electrical measurement results show that the upper and bottom wires with a width of 100 µm can sustain a 6 A current without burnout. Another focus of this study is the double-layer atom chips integrated with the through silicon via (TSV) technique, and anodically bonded to a Pyrex glass cell, which makes it a desired vacuum chamber for atomic physics experiments. Thus, the bonded glass cell not only significantly reduces the overall size of the ultra-high-vacuum (UHV) chamber but also conducts the high current from the backside to the front side of the atom chip via the TSV under UHV (9.5 × 10-10 Torr). The TSVs with a diameter of 70 µm were etched through by the inductively coupled plasma ion etching and filled by the bottom-up copper electroplating method. During the anodic bonding process, the electroplated copper wires and TSVs on atom chips also need to pass the examination of the required bonding temperature of 250 °C, under an applied voltage of 1000 V. Finally, the UHV test of the double-layer atom chips with TSVs at room temperature can be reached at 9.5 × 10-10 Torr, thus satisfying the requirements of atomic physics experiments under an UHV environment.

Probable effects on ground-water resources from construction of the proposed Grand River cut-off channel west of Lansing, Mich.

USGS Publications Warehouse

Ferris, John G.

1950-01-01

This memorandum summarize information brought out in correspondence between the office of the District Engineer of the Milwaukee District, U.S. Corps of Engineers, and the District Office of the Ground Water Branch of the U.S. Geological Survey at Lansing, Mich., concerning the probable effects on the ground-water resources of the Lansing area from the construction of a proposed flood-water cut-off channel for the Grand River to extend from Millett to Delta Mills, in Eaton County, Mich.

Calibrated Link Budget of a Silicon Photonics WDM Transceiver with SOA and Semiconductor Mode-Locked Laser.

PubMed

Moscoso-Mártir, Alvaro; Müller, Juliana; Islamova, Elmira; Merget, Florian; Witzens, Jeremy

2017-09-20

Based on the single channel characterization of a Silicon Photonics (SiP) transceiver with Semiconductor Optical Amplifier (SOA) and semiconductor Mode-Locked Laser (MLL), we evaluate the optical power budget of a corresponding Wavelength Division Multiplexed (WDM) link in which penalties associated to multi-channel operation and the management of polarization diversity are introduced. In particular, channel cross-talk as well as Cross Gain Modulation (XGM) and Four Wave Mixing (FWM) inside the SOA are taken into account. Based on these link budget models, the technology is expected to support up to 12 multiplexed channels without channel pre-emphasis or equalization. Forward Error Correction (FEC) does not appear to be required at 14 Gbps if the SOA is maintained at 25 °C and MLL-to-SiP as well as SiP-to-SOA interface losses can be maintained below 3 dB. In semi-cooled operation with an SOA temperature below 55 °C, multi-channel operation is expected to be compatible with standard 802.3bj Reed-Solomon FEC at 14 Gbps provided interface losses are maintained below 4.5 dB. With these interface losses and some improvements to the Transmitter (Tx) and Receiver (Rx) electronics, 25 Gbps multi-channel operation is expected to be compatible with 7% overhead hard decision FEC.

The formation mechanism of defects, spiral wave in the network of neurons.

PubMed

Wu, Xinyi; Ma, Jun

2013-01-01

A regular network of neurons is constructed by using the Morris-Lecar (ML) neuron with the ion channels being considered, and the potential mechnism of the formation of a spiral wave is investigated in detail. Several spiral waves are initiated by blocking the target wave with artificial defects and/or partial blocking (poisoning) in ion channels. Furthermore, possible conditions for spiral wave formation and the effect of partial channel blocking are discussed completely. Our results are summarized as follows. 1) The emergence of a target wave depends on the transmembrane currents with diversity, which mapped from the external forcing current and this kind of diversity is associated with spatial heterogeneity in the media. 2) Distinct spiral wave could be induced to occupy the network when the target wave is broken by partially blocking the ion channels of a fraction of neurons (local poisoned area), and these generated spiral waves are similar with the spiral waves induced by artificial defects. It is confirmed that partial channel blocking of some neurons in the network could play a similar role in breaking a target wave as do artificial defects; 3) Channel noise and additive Gaussian white noise are also considered, and it is confirmed that spiral waves are also induced in the network in the presence of noise. According to the results mentioned above, we conclude that appropriate poisoning in ion channels of neurons in the network acts as 'defects' on the evolution of the spatiotemporal pattern, and accounts for the emergence of a spiral wave in the network of neurons. These results could be helpful to understand the potential cause of the formation and development of spiral waves in the cortex of a neuronal system.

The Formation Mechanism of Defects, Spiral Wave in the Network of Neurons

PubMed Central

Wu, Xinyi; Ma, Jun

2013-01-01

A regular network of neurons is constructed by using the Morris-Lecar (ML) neuron with the ion channels being considered, and the potential mechnism of the formation of a spiral wave is investigated in detail. Several spiral waves are initiated by blocking the target wave with artificial defects and/or partial blocking (poisoning) in ion channels. Furthermore, possible conditions for spiral wave formation and the effect of partial channel blocking are discussed completely. Our results are summarized as follows. 1) The emergence of a target wave depends on the transmembrane currents with diversity, which mapped from the external forcing current and this kind of diversity is associated with spatial heterogeneity in the media. 2) Distinct spiral wave could be induced to occupy the network when the target wave is broken by partially blocking the ion channels of a fraction of neurons (local poisoned area), and these generated spiral waves are similar with the spiral waves induced by artificial defects. It is confirmed that partial channel blocking of some neurons in the network could play a similar role in breaking a target wave as do artificial defects; 3) Channel noise and additive Gaussian white noise are also considered, and it is confirmed that spiral waves are also induced in the network in the presence of noise. According to the results mentioned above, we conclude that appropriate poisoning in ion channels of neurons in the network acts as ‘defects’ on the evolution of the spatiotemporal pattern, and accounts for the emergence of a spiral wave in the network of neurons. These results could be helpful to understand the potential cause of the formation and development of spiral waves in the cortex of a neuronal system. PMID:23383179

"Space slitter" for film or tape

NASA Technical Reports Server (NTRS)

Johnson, W. H.

1978-01-01

Device cuts film or tape into strips by guiding film in channel under cutting blades. Device is operated by lifting pressure bar to insert blades into film. Film is then pulled through blades. Cutter has potential uses in advertising, commercial art, and publishing fields.

Sugaring marble in the Monumental Cemetery in Bologna (Italy): characterization of naturally and artificially weathered samples and first results of consolidation by hydroxyapatite

NASA Astrophysics Data System (ADS)

Sassoni, Enrico; Franzoni, Elisa

2014-12-01

The so-called sugaring of marble is a very common degradation phenomenon, affecting both historical monuments and modern buildings, which is originated by environmental temperature fluctuations. Thermal cycles are indeed responsible for micro-cracks formation at the boundaries between calcite grains, so that marble is subjected to granular disintegration and can be reduced to a sugar-like powder of isolated calcite grains by just the pressure of a finger. Since no effective, compatible and durable treatment for sugaring marble consolidation is currently available, in this paper a novel consolidating treatment recently proposed for limestone, based on the formation of hydroxyapatite inside the stone, was investigated for weathered marble. To test the new treatment on suitably decayed marble samples, some naturally sugaring marbles from the Monumental Cemetery in Bologna (Italy, nineteenth century) were firstly characterized by scanning electron microscope (SEM), mercury intrusion porosimetry (MIP) and ultrasonic pulse velocity (UPV) measurement. Then, artificially weathered samples were produced by heating fresh Carrara marble samples at 400 °C for 1 h. The effects of artificial weathering were characterized using the same techniques as above, and a very good agreement was found between microstructure and mechanical features of naturally and artificially weathered samples. Then, the hydroxyapatite-based treatment was tested on the so-obtained artificially weathered samples, and the treatment effects were characterized by UPV, MIP and SEM equipped with energy dispersive spectrometry and Fourier transform infrared spectroscopy. The hydroxyapatite-based treatment exhibited a remarkable ability of restoring marble cohesion and a good compatibility in terms of modifications in pore size distribution, which leads to regard this treatment as a very promising consolidant for weathered marble.

Holocene evolution of the merrimack embayment, northern massachusetts, interperted from shallow seismic stratigraphy

USGS Publications Warehouse

Hein, C.J.; FitzGerald, D.M.; Barnhardt, W.A.

2007-01-01

Recent multi-beam, backscatter, and bottom sediment data demonstrate that a large sand sheet was formed in the inner shelf by the reworking of the Merrimack River lowstand delta and braid plain (12 kya) during the Holocene transgression. Seismic data reveal the presence of widespread channel cut-and-fill structures landward of the delta suggesting that much of the sand sheet consists of braided stream deposits. These features map into several sets of cut-and-fill structures, indicating the avulsion of the primary river channels, which creates the lobes of the paleo-delta. Truncations of these, cut-and-fill structures suggest that the braid plain deposits were probably reworked during the Holocene transgression and may have contributed sand to developing barriers that presently border the Merrimack Embayment.

The development of a portable ultrahigh vacuum chamber via silicon block.

PubMed

Chuang, Ho-Chiao; Huang, Chia-Shiuan

2014-05-01

This paper describes a nonmetallic, light weight portable chamber for ultra-high vacuum (UHV) applications. The chamber consists of a processed silicon block anodically bonding five polished Pyrex glass windows and a Pyrex glass adapter, without using any screws, bolts or vacuum adhesives. The design features provide an alternative chamber for UHV applications which require nonmetallic components. We have cyclically baked the chamber up to 180 °C for 160 h and have achieved an ultimate pressure of 1.4 × 10(-9) Torr (limited by our pumping station), with no leak detected. Both Pyrex glass windows and Pyrex glass adapter have been used successfully.

UHV-TEM/TED observation of Ag islands grown on Si( 1 1 1 ) 3× 3-Ag surface

NASA Astrophysics Data System (ADS)

Oshima, Yoshifumi; Nakade, Hiroyuki; Shigeki, Sinya; Hirayama, Hiroyuki; Takayanagi, Kunio

2001-11-01

Growths of Ag islands on Si(1 1 1)3×3-Ag surface at room temperature were observed by UHV transmission electron microscopy and diffraction. The Ag islands grown after six monolayer deposition had neither (1 0 0) nor (1 1 0) orientation, but had two complex epitaxial orientations dominantly. One was striped islands which gave rise to a diffraction pattern commensurate with the 3×3 lattice of the Si(1 1 1) surface. The other was the coagulated islands whose diffraction pattern indicated the Ag(1 -3 4) sheet grown parallel to the Si(1 1 1) surface.

Surface Structure of TiO2 Rutile (011) Exposed to Liquid Water

PubMed Central

2017-01-01

The rutile TiO2(011) surface exhibits a (2 × 1) reconstruction when prepared by standard techniques in ultrahigh vacuum (UHV). Here we report that a restructuring occurs upon exposing the surface to liquid water at room temperature. The experiment was performed in a dedicated UHV system, equipped for direct and clean transfer of samples between UHV and liquid environment. After exposure to liquid water, an overlayer with a (2 × 1) symmetry was observed containing two dissociated water molecules per unit cell. The two OH groups yield an apparent “c(2 × 1)” symmetry in scanning tunneling microscopy (STM) images. On the basis of STM analysis and density functional theory (DFT) calculations, this overlayer is attributed to dissociated water on top of the unreconstructed (1 × 1) surface. Investigation of possible adsorption structures and analysis of the domain boundaries in this structure provide strong evidence that the original (2 × 1) reconstruction is lifted. Unlike the (2 × 1) reconstruction, the (1 × 1) surface has an appropriate density and symmetry of adsorption sites. The possibility of contaminant-induced restructuring was excluded based on X-ray photoelectron spectroscopy (XPS) and low-energy He+ ion scattering (LEIS) measurements. PMID:29285204

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

Posch, J.

Systems and philosophies perceived on a grand scale, encompassing new ideas, are often characterized as a dream. But in fact, such dreams often lead to the first step to fruitful development. This article is based on a preliminary study of the existing electrical high-tension networks of Western Europe, Eastern Europe and the Soviet Union - which, as explained herein, may be merged into a multinational energy supply system. Such a system would constitute a completely interconnected Eurasian Power Grid. The idea of a Eurasian super grid, spanning from the Atlantic to the Ural and Siberia, is not new. Various studiesmore » have been conducted by both western Europe and the Soviet Union on this topic. Our world is currently in an era of extra high voltage (EHV) and ultra high voltage (UHV) electrical systems. This translates into existing UHV lines of 1150 kV which have already been proven in successful operation. Such UHV systems are capable of transmitting thousands of megawatts over a distance of a 1000 miles. Furthermore, national boundaries are not more a hindrance than the challenge of interconnecting complete networks into an overall synchronized working system with load exchange capabilities in all directions.« less

NC-AFM observation of atomic scale structure of rutile-type TiO2(110) surface prepared by wet chemical process.

PubMed

Namai, Yoshimichi; Matsuoka, Osamu

2006-04-06

We succeeded in observing the atomic scale structure of a rutile-type TiO2(110) single-crystal surface prepared by the wet chemical method of chemical etching in an acid solution and surface annealing in air. Ultrahigh vacuum noncontact atomic force microscopy (UHV-NC-AFM) was used for observing the atomic scale structures of the surface. The UHV-NC-AFM measurements at 450 K, which is above a desorption temperature of molecularly adsorbed water on the TiO2(110) surface, enabled us to observe the atomic scale structure of the TiO2(110) surface prepared by the wet chemical method. In the UHV-NC-AFM measurements at room temperature (RT), however, the atomic scale structure of the TiO2(110) surface was not observed. The TiO2(110) surface may be covered with molecularly adsorbed water after the surface was prepared by the wet chemical method. The structure of the TiO2(110) surface that was prepared by the wet chemical method was consistent with the (1 x 1) bulk-terminated model of the TiO2(110) surface.

An ultra-high vacuum scanning tunneling microscope operating at sub-Kelvin temperatures and high magnetic fields for spin-resolved measurements

NASA Astrophysics Data System (ADS)

Salazar, C.; Baumann, D.; Hänke, T.; Scheffler, M.; Kühne, T.; Kaiser, M.; Voigtländer, R.; Lindackers, D.; Büchner, B.; Hess, C.

2018-06-01

We present the construction and performance of an ultra-low-temperature scanning tunneling microscope (STM), working in ultra-high vacuum (UHV) conditions and in high magnetic fields up to 9 T. The cryogenic environment of the STM is generated by a single-shot 3He magnet cryostat in combination with a 4He dewar system. At a base temperature (300 mK), the cryostat has an operation time of approximately 80 h. The special design of the microscope allows the transfer of the STM head from the cryostat to a UHV chamber system, where samples and STM tips can be easily exchanged. The UHV chambers are equipped with specific surface science treatment tools for the functionalization of samples and tips, including high-temperature treatments and thin film deposition. This, in particular, enables spin-resolved tunneling measurements. We present test measurements using well-known samples and tips based on superconductors and metallic materials such as LiFeAs, Nb, Fe, and W. The measurements demonstrate the outstanding performance of the STM with high spatial and energy resolution as well as the spin-resolved capability.

78 FR 33221 - Special Local Regulation; Annual Swim Around Key West, Atlantic Ocean and Gulf of Mexico; Key...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-04

... Fort Zach State Park, North through Key West Harbor, East through Flemming Cut, South on Cow Key... State Park, North through Key West Harbor, East through Flemming Cut, South on Cow Key Channel and West...

Electrical contact tool set station

DOEpatents

Byers, M.E.

1988-02-22

An apparatus is provided for the precise setting to zero of electrically conductive cutting tools used in the machining of work pieces. An electrically conductive cylindrical pin, tapered at one end to a small flat, rests in a vee-shaped channel in a base so that its longitudinal axis is parallel to the longitudinal axis of the machine's spindle. Electronic apparatus is connected between the cylindrical pin and the electrically conductive cutting tool to produce a detectable signal when contact between tool and pin is made. The axes of the machine are set to zero by contact between the cutting tool and the sides, end or top of the cylindrical pin. Upon contact, an electrical circuit is completed, and the detectable signal is produced. The tool can then be set to zero for that axis. Should the tool contact the cylindrical pin with too much force, the cylindrical pin would be harmlessly dislodged from the vee-shaped channel, preventing damage either to the cutting tool or the cylindrical pin. 5 figs.

Achieving high permeability and enhanced selectivity for Angstrom-scale separations using artificial water channel membranes.

PubMed

Shen, Yue-Xiao; Song, Woochul C; Barden, D Ryan; Ren, Tingwei; Lang, Chao; Feroz, Hasin; Henderson, Codey B; Saboe, Patrick O; Tsai, Daniel; Yan, Hengjing; Butler, Peter J; Bazan, Guillermo C; Phillip, William A; Hickey, Robert J; Cremer, Paul S; Vashisth, Harish; Kumar, Manish

2018-06-12

Synthetic polymer membranes, critical to diverse energy-efficient separations, are subject to permeability-selectivity trade-offs that decrease their overall efficacy. These trade-offs are due to structural variations (e.g., broad pore size distributions) in both nonporous membranes used for Angstrom-scale separations and porous membranes used for nano to micron-scale separations. Biological membranes utilize well-defined Angstrom-scale pores to provide exceptional transport properties and can be used as inspiration to overcome this trade-off. Here, we present a comprehensive demonstration of such a bioinspired approach based on pillar[5]arene artificial water channels, resulting in artificial water channel-based block copolymer membranes. These membranes have a sharp selectivity profile with a molecular weight cutoff of ~ 500 Da, a size range challenging to achieve with current membranes, while achieving a large improvement in permeability (~65 L m -2  h -1  bar -1  compared with 4-7 L m -2  h -1  bar -1 ) over similarly rated commercial membranes.

European Scientific Notes. Volume 36, Number 7,

DTIC Science & Technology

1982-07-31

services digital net- works, lierarhicel processing, of structural information in artificial intelligence. and human-machine interaction and digital...reduction in the rate of in those days were connected by "fossae" or growth and even the initiation of erosion along artificial channels. Thus littoral...fisher- Comacchio (see map) in the eighth century. men who would like to increase it. Additional The present Po delta is artificial in that conflicts

Abundance of juvenile eastern box turtles in manages forest stands

Treesearch

Z. Felix; Y. Wang; H. Czech; C. Schweitzer

2008-01-01

Between 2002 and 2005, we used drift fences and artificial pools to sample juvenile eastern box turtles (Terrapene carolina) in northeastern Alabama in forest stands experimentally treated to retain various amounts of overstory trees—clear-cuts and those with 25%–50% and 75%–100% of trees retained.We captured juvenile turtles only in clear-cut and 25%–50% retention...

Magnetically-actuated artificial cilia for microfluidic propulsion.

PubMed

Khaderi, S N; Craus, C B; Hussong, J; Schorr, N; Belardi, J; Westerweel, J; Prucker, O; Rühe, J; den Toonder, J M J; Onck, P R

2011-06-21

In this paper we quantitatively analyse the performance of magnetically-driven artificial cilia for lab-on-a-chip applications. The artificial cilia are fabricated using thin polymer films with embedded magnetic nano-particles and their deformation is studied under different external magnetic fields and flows. A coupled magneto-mechanical solid-fluid model that accurately captures the interaction between the magnetic field, cilia and fluid is used to simulate the cilia motion. The elastic and magnetic properties of the cilia are obtained by fitting the results of the computational model to the experimental data. The performance of the artificial cilia with a non-uniform cross-section is characterised using the numerical model for two channel configurations that are of practical importance: an open-loop and a closed-loop channel. We predict that the flow and pressure head generated by the artificial cilia can be as high as 18 microlitres per minute and 3 mm of water, respectively. We also study the effect of metachronal waves on the flow generated and show that the fluid propelled increases drastically compared to synchronously beating cilia, and is unidirectional. This increase is significant even when the phase difference between adjacent cilia is small. The obtained results provide guidelines for the optimal design of magnetically-driven artificial cilia for microfluidic propulsion.

Development of Stable Liquid Glucagon Formulations for Use in Artificial Pancreas

PubMed Central

Li, Ming; Krasner, Alan; De Souza, Errol

2014-01-01

Background: A promising approach to treat diabetes is the development of fully automated artificial/bionic pancreas systems that use both insulin and glucagon to maintain euglycemia. A physically and chemically stable liquid formulation of glucagon does not currently exist. Our goal is to develop a glucagon formulation that is stable as a clear and gel-free solution, free of fibrils and that has the requisite long-term shelf life for storage in the supply chain, short-term stability for at least 7 days at 37°C, and pump compatibility for use in a bihormonal pump. Methods: We report the development of two distinct families of stable liquid glucagon formulations which utilize surfactant or surfactant-like excipients (LMPC and DDM) to “immobilize” the glucagon in solution potentially through the formation of micelles and prevention of interaction between glucagon molecules. Results: Data are presented that demonstrate long-term physical and chemical stability (~2 years) at 5°C, short-term stability (up to 1 month) under accelerated 37°C testing conditions, pump compatibility for up to 9 days, and adequate glucose responses in dogs and diabetic swine. Conclusions: These stable glucagon formulations show utility and promise for further development in artificial pancreas systems. PMID:25352634

A review of pipe and bamboo artificial refugia as sampling tools in anuran studies

USGS Publications Warehouse

Glorioso, Brad M.; Waddle, J. Hardin

2014-01-01

Artificial pipe-like refugia have been used for more than 40 years in anuran studies, and have captured 28 species, primarily (82%) hylid treefrogs. Early pipe-like refugia were made using cut pieces of bamboo in the tropical forests of Puerto Rico, but most recent studies have used synthetic pipes and have occurred primarily in the southeastern United States. Characteristics of artificial refugia (e.g., color, length, and diameter), and their placement in the environment have varied greatly among studies, making comparisons difficult. Here, we summarize and evaluate different pipe designs and placement, address potential concerns when using artificial pipe-like refugia, and suggest studies necessary to better interpret the data gained from this technique in anuran studies.

Remineralization of artificial enamel lesions by theobromine.

PubMed

Amaechi, B T; Porteous, N; Ramalingam, K; Mensinkai, P K; Ccahuana Vasquez, R A; Sadeghpour, A; Nakamoto, T

2013-01-01

This study investigated the remineralization potential of theobromine in comparison to a standard NaF dentifrice. Three tooth blocks were produced from each of 30 teeth. Caries-like lesion was created on each block using acidified gel. A smaller block was cut from each block for baseline scanning electron microscopy imaging and electron-dispersive spectroscopy (EDS) analysis for surface Ca level. A tooth slice was cut from each lesion-bearing block for transverse microradiography (TMR) quantification of baseline mineral loss (Δz) and lesion depth (LD). Then baseline surface microhardness (SMH) of each lesion was measured. The three blocks from each tooth were assigned to three remineralizing agents: (1) artificial saliva; (2) artificial saliva with theobromine (0.0011 mol/l), and (3) NaF toothpaste slurry (0.0789 mol/l F). Remineralization was conducted using a pH cycling model with storage in artificial saliva. After a 28-day cycle, samples were analyzed using EDS, TMR, and SMH. Intragroup comparison of pre- and posttest data was performed using t tests (p < 0.05). Intergroup comparisons were performed by post hoc multistep comparisons (Tukey). SMH indicated significant (p < 0.01) remineralization only with theobromine (38 ± 32%) and toothpaste (29 ± 16%). With TMR (Δz/lD), theobromine and toothpaste exhibited significantly (p < 0.01) higher mineral gain relative to artificial saliva. With SMH and TMR, remineralization produced by theobromine and toothpaste was not significantly different. With EDS, calcium deposition was significant in all groups, but not significantly different among the groups (theobromine 13 ± 8%, toothpaste 10 ± 5%, and artificial saliva 6 ± 8%). The present study demonstrated that theobromine in an apatite-forming medium can enhance the remineralization potential of the medium. Copyright © 2013 S. Karger AG, Basel.

Development of an Artificial Gravity Sleeper (AGS)

NASA Technical Reports Server (NTRS)

Cardus, David; Mctaggart, Wesley G.; Diamandis, Peter; Campbell, Scott

1990-01-01

The design and construction of a 2-meter radius 'human compatible' centrifuge termed the Artificial Gravity Sleeper (AGS) is considered. The centrifuge will accommodate up to four subjects at a time, operate at a broad range of speeds, and have safety features. Experiments that will be conducted on the AGS will help to investigate the quality of sleep during 100 percent gradient centrifugation. A microgravity simulation also will be studied using bed rest to assess the ability of 100 percent gradient centrifugation to function as a countermeasure to cardiovascular deconditioning.

Bedrock channel reaches morphology: examples from the Northern Marche Region (Italy)

NASA Astrophysics Data System (ADS)

Tiberi, V.; di Agostino, V.; Troiani, F.; Nesci, O.; Savelli, D.

2009-04-01

The Northern Marche rivers, on account of a significant variability of their catchment geology, geodynamics and geomorphology, can be regarded as excellent natural laboratories for the study of the morphology, dynamics and evolution of bedrock channel reaches. Hence a geomorphologic study has been carried on in order to map and describe -from qualitative and quantitative point of view- some bedrock channel types of this area, to detect morphological controls at different scales (from the local scale up to the catchment one), and to assess human perturbations on the drainage systems. The study is based on detailed field surveying concerning channel shape and dynamics, floodplain configurations, slope geomorphologic processes, bedrock structure and composition. In addiction, a good aero photograph documentation dating back to the 1955 allowed a reliable reconstruction of the main evolution trends of bedrock channel reaches in the latest past. In the reported rivers the bedrock channel reaches vary in length from a few tens to hundreds of meters, and alternate with alluvial and mixed bedrock-alluvial channel reaches. In many cases specific numerical relations among geometric parameters of bedrock channels have been discovered and some similarities in both morphology and dynamics of rock-cut channels with alluvial channel reaches have been pointed out. Specifically, with regard of their morphologic arrangement, geometric parameters, and flow dynamics several bedrock channels are quite similar to step pool channels found along gravelly channel reaches. Nonetheless, along a given segment of the hydrographical network where an individual alluvial-channel pattern (e.g. a wandering) is found both upstream and downstream a rock-cut channel reach, the occurrence of this latter (e.g. planar bedrock-floored channel) simply breaks the along-stream continuity of the alluvial-bed morphology.

Dimming LEDs with Phase-Cut Dimmers. The Specifier's Process for Maximizing Success

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

Miller, N. J.; Poplawski, M. E.

2013-10-01

DOE GATEWAY program report reviewing how phase-cut dimmers work, how LEDs differ from the incandescent lamps these dimmers were originally designed to control, and how those differences can lead to complications when attempting to dim LEDs. Providing both general guidance and step-by-step procedures for designing phase-controlled LED dimming on both new and existing projects—as well as real-world examples of how to use those procedures—the report aims to reduce the chance of experiencing compatibility-related problems and, if possible, ensure good dimming performance.

Device-independent tests of quantum channels

NASA Astrophysics Data System (ADS)

Dall'Arno, Michele; Brandsen, Sarah; Buscemi, Francesco

2017-03-01

We develop a device-independent framework for testing quantum channels. That is, we falsify a hypothesis about a quantum channel based only on an observed set of input-output correlations. Formally, the problem consists of characterizing the set of input-output correlations compatible with any arbitrary given quantum channel. For binary (i.e. two input symbols, two output symbols) correlations, we show that extremal correlations are always achieved by orthogonal encodings and measurements, irrespective of whether or not the channel preserves commutativity. We further provide a full, closed-form characterization of the sets of binary correlations in the case of: (i) any dihedrally covariant qubit channel (such as any Pauli and amplitude-damping channels) and (ii) any universally-covariant commutativity-preserving channel in an arbitrary dimension (such as any erasure, depolarizing, universal cloning and universal transposition channels).

Device-independent tests of quantum channels.

PubMed

Dall'Arno, Michele; Brandsen, Sarah; Buscemi, Francesco

2017-03-01

We develop a device-independent framework for testing quantum channels. That is, we falsify a hypothesis about a quantum channel based only on an observed set of input-output correlations. Formally, the problem consists of characterizing the set of input-output correlations compatible with any arbitrary given quantum channel. For binary (i.e. two input symbols, two output symbols) correlations, we show that extremal correlations are always achieved by orthogonal encodings and measurements, irrespective of whether or not the channel preserves commutativity. We further provide a full, closed-form characterization of the sets of binary correlations in the case of: (i) any dihedrally covariant qubit channel (such as any Pauli and amplitude-damping channels) and (ii) any universally-covariant commutativity-preserving channel in an arbitrary dimension (such as any erasure, depolarizing, universal cloning and universal transposition channels).

21 CFR 133.165 - Parmesan and reggiano cheese.

Code of Federal Regulations, 2010 CFR

2010-04-01

... milk to a semisolid mass. Harmless artificial coloring may be added. The mass is cut into pieces no... alum, calcium sulfate, and magnesium carbonate, singly or combined, is not more than six times the...

Breeding behaviour of Kunzea pomifera (Myrtaceae): self-incompatibility, intraspecific and interspecific cross-compatibility.

PubMed

Page, T; Moore, G M; Will, J; Halloran, G M

2010-09-01

To examine breeding system characteristics of the endemic Australian prostrate shrub Kunzea pomifera, artificial hybridisations were undertaken using thirteen different genotypes of K. pomifera, to elucidate: (1) self-incompatibility, (2) intraspecific cross-compatibility in the species and (3) interspecific cross-compatibility with each of K. ambigua and K. ericoides. K. pomifera exhibited very low self-compatibility, with the barrier to self-fertilisation being prevention of pollen-tube growth in the style or ovary. Following intraspecific pollination amongst a number of different genotypes of K. pomifera, 38.4% of pollinated flowers developed fruit; arrest of compatible pollen-tubes in the style, preventing fertilisation, contributes to the low fruit set in this species. Interspecific compatibility was examined between K. pomifera (pistillate parent) and K. ambigua (staminate parent) where seed set per pollinated flower (4.47) was not significantly different from intraspecific crosses (4.66). In crosses between K. pomifera (pistillate parent) and K. ericoides as staminate plant, 0.037% of pollinated flowers produced fruit, with 0.0075 seeds per pollinated flower. Reproductive barriers between these two species were evident in the style of K. pomifera, where the growing tips of the K. ericoides pollen-tubes swelled and ceased to grow.

Single-channel in-ear-EEG detects the focus of auditory attention to concurrent tone streams and mixed speech.

PubMed

Fiedler, Lorenz; Wöstmann, Malte; Graversen, Carina; Brandmeyer, Alex; Lunner, Thomas; Obleser, Jonas

2017-06-01

Conventional, multi-channel scalp electroencephalography (EEG) allows the identification of the attended speaker in concurrent-listening ('cocktail party') scenarios. This implies that EEG might provide valuable information to complement hearing aids with some form of EEG and to install a level of neuro-feedback. To investigate whether a listener's attentional focus can be detected from single-channel hearing-aid-compatible EEG configurations, we recorded EEG from three electrodes inside the ear canal ('in-Ear-EEG') and additionally from 64 electrodes on the scalp. In two different, concurrent listening tasks, participants (n  =  7) were fitted with individualized in-Ear-EEG pieces and were either asked to attend to one of two dichotically-presented, concurrent tone streams or to one of two diotically-presented, concurrent audiobooks. A forward encoding model was trained to predict the EEG response at single EEG channels. Each individual participants' attentional focus could be detected from single-channel EEG response recorded from short-distance configurations consisting only of a single in-Ear-EEG electrode and an adjacent scalp-EEG electrode. The differences in neural responses to attended and ignored stimuli were consistent in morphology (i.e. polarity and latency of components) across subjects. In sum, our findings show that the EEG response from a single-channel, hearing-aid-compatible configuration provides valuable information to identify a listener's focus of attention.

Hyperviscosity for unstructured ALE meshes

NASA Astrophysics Data System (ADS)

Cook, Andrew W.; Ulitsky, Mark S.; Miller, Douglas S.

2013-01-01

An artificial viscosity, originally designed for Eulerian schemes, is adapted for use in arbitrary Lagrangian-Eulerian simulations. Changes to the Eulerian model (dubbed 'hyperviscosity') are discussed, which enable it to work within a Lagrangian framework. New features include a velocity-weighted grid scale and a generalised filtering procedure, applicable to either structured or unstructured grids. The model employs an artificial shear viscosity for treating small-scale vorticity and an artificial bulk viscosity for shock capturing. The model is based on the Navier-Stokes form of the viscous stress tensor, including the diagonal rate-of-expansion tensor. A second-order version of the model is presented, in which Laplacian operators act on the velocity divergence and the grid-weighted strain-rate magnitude to ensure that the velocity field remains smooth at the grid scale. Unlike sound-speed-based artificial viscosities, the hyperviscosity model is compatible with the low Mach number limit. The new model outperforms a commonly used Lagrangian artificial viscosity on a variety of test problems.

Cooper Lake and Channels, Texas.

DTIC Science & Technology

1977-04-01

maintenance. Adverse esthetic impacts of the channel and levees. Inundation of some 90 archeo- logical sites which have been tested to the extent...below the reservoir was approximately ’,0 percent complete. In June 1976, the draft environmental impact statement (EIS) was coordinated for review and...construction necessitates cutting off natural channel bends. 3. a. Environmental Impacts : (I) Reservoir. The flood storage space in the approved

Impacts of changing hydrology on permanent gully growth: experimental results

NASA Astrophysics Data System (ADS)

Day, Stephanie S.; Gran, Karen B.; Paola, Chris

2018-06-01

Permanent gullies grow through head cut propagation in response to overland flow coupled with incision and widening in the channel bottom leading to hillslope failures. Altered hydrology can impact the rate at which permanent gullies grow by changing head cut propagation, channel incision, and channel widening rates. Using a set of small physical experiments, we tested how changing overland flow rates and flow volumes alter the total volume of erosion and resulting gully morphology. Permanent gullies were modeled as both detachment-limited and transport-limited systems, using two different substrates with varying cohesion. In both cases, the erosion rate varied linearly with water discharge, such that the volume of sediment eroded was a function not of flow rate, but of total water volume. This implies that efforts to reduce peak flow rates alone without addressing flow volumes entering gully systems may not reduce erosion. The documented response in these experiments is not typical when compared to larger preexisting channels where higher flow rates result in greater erosion through nonlinear relationships between water discharge and sediment discharge. Permanent gullies do not respond like preexisting channels because channel slope remains a free parameter and can adjust relatively quickly in response to changing flows.

Artificial Structural Color Pixels: A Review

PubMed Central

Zhao, Yuqian; Zhao, Yong; Hu, Sheng; Lv, Jiangtao; Ying, Yu; Gervinskas, Gediminas; Si, Guangyuan

2017-01-01

Inspired by natural photonic structures (Morpho butterfly, for instance), researchers have demonstrated varying artificial color display devices using different designs. Photonic-crystal/plasmonic color filters have drawn increasing attention most recently. In this review article, we show the developing trend of artificial structural color pixels from photonic crystals to plasmonic nanostructures. Such devices normally utilize the distinctive optical features of photonic/plasmon resonance, resulting in high compatibility with current display and imaging technologies. Moreover, dynamical color filtering devices are highly desirable because tunable optical components are critical for developing new optical platforms which can be integrated or combined with other existing imaging and display techniques. Thus, extensive promising potential applications have been triggered and enabled including more abundant functionalities in integrated optics and nanophotonics. PMID:28805736

Thrombotic Depositions on Right Impeller of Double-Ended Centrifugal Total Artificial Heart In Vivo.

PubMed

Karimov, Jamshid H; Horvath, David J; Okano, Shinji; Goodin, Mark; Sunagawa, Gengo; Byram, Nicole; Moazami, Nader; Golding, Leonard A R; Fukamachi, Kiyotaka

2017-05-01

The development of total artificial heart devices is a complex undertaking that includes chronic biocompatibility assessment of the device. It is considered particularly important to assess whether device design and features can be compatible long term in a biological environment. As part of the development program for the Cleveland Clinic continuous-flow total artificial heart (CFTAH), we evaluated the device for signs of thrombosis and biological material deposition in four animals that had achieved the intended 14-, 30-, or 90-day durations in each respective experiment. Explanted CFTAHs were analyzed for possible clot buildup at "susceptible" areas inside the pump, particularly the right pump impeller. Depositions of various consistency and shapes were observed. We here report our findings, along with macroscopic and microscopic analysis post explant, and provide computational fluid dynamics data with its potential implications for thrombus formation. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Possibilities of psychoacoustics to determine sound quality

NASA Astrophysics Data System (ADS)

Genuit, Klaus

For some years, acoustic engineers have increasingly become aware of the importance of analyzing and minimizing noise problems not only with regard to the A-weighted sound pressure level, but to design sound quality. It is relatively easy to determine the A-weighted SPL according to international standards. However, the objective evaluation to describe subjectively perceived sound quality - taking into account psychoacoustic parameters such as loudness, roughness, fluctuation strength, sharpness and so forth - is more difficult. On the one hand, the psychoacoustic measurement procedures which are known so far have yet not been standardized. On the other hand, they have only been tested in laboratories by means of listening tests in the free-field and one sound source and simple signals. Therefore, the results achieved cannot be transferred to complex sound situations with several spatially distributed sound sources without difficulty. Due to the directional hearing and selectivity of human hearing, individual sound events can be selected among many. Already in the late seventies a new binaural Artificial Head Measurement System was developed which met the requirements of the automobile industry in terms of measurement technology. The first industrial application of the Artificial Head Measurement System was in 1981. Since that time the system was further developed, particularly by the cooperation between HEAD acoustics and Mercedes-Benz. In addition to a calibratable Artificial Head Measurement System which is compatible with standard measurement technologies and has transfer characteristics comparable to human hearing, a Binaural Analysis System is now also available. This system permits the analysis of binaural signals regarding physical and psychoacoustic procedures. Moreover, the signals to be analyzed can be simultaneously monitored through headphones and manipulated in the time and frequency domain so that those signal components being responsible for noise annoyance can be found. Especially in complex sound situations with several spatially distributed sound sources, standard, one-channel measurements methods cannot adequately determine sound quality, the acoustic comfort, or annoyance of sound events.

Towards crack-free ablation cutting of thin glass sheets with picosecond pulsed lasers

NASA Astrophysics Data System (ADS)

Sun, Mingying; Eppelt, Urs; Hartmann, Claudia; Schulz, Wolfgang; Zhu, Jianqiang; Lin, Zunqi

2017-08-01

We investigated the morphology and mechanism of laser-induced damage in the ablation cutting of thin glass sheets with picosecond laser. Two kinds of damage morphologies observed on the cross-section of the cut channel, are caused by high-density free-electrons and the temperature accumulation, respectively. Notches and micro-cracks can be observed on the top surface of the sample near the cut edge. The surface micro-cracks were related to high energy free-electrons and also the heat-affected zone. Heat-affected-zone and visible-cracks free conditions of glass cutting were achieved by controlling the repetition rate and spatial overlap of laser pulses.

Features of precision slot cutting with a large number of calibers using the radiation of a single-mode fiber laser

NASA Astrophysics Data System (ADS)

Vitshas, A. A.; Zelentsov, A. G.; Lopota, V. A.; Menakhin, V. P.; Panchenko, V. P.; Soroka, A. M.

2014-02-01

The results of the experimental and theoretical investigations aimed at determining the characteristics and features of precision slot cutting with a large number of calibers in sheets of low-carbon steel using the radiation of a single-mode fiber laser with pulse power up to 1 kW are presented. The description of the experimental installation, performance conditions of investigations, and variable parameters are described. Precision cutting of low-carbon steel up to 10 mm with the number of calibers ranging from 30 to 70 at a slot width of ≈60 μm is performed for the first time. Such cutting occurs only in the pulsed-periodic mode using single-mode radiation with a pulse duration of 2-3 ms, a pulse ratio of 2-4, and oxygen, whose influence differs in principle both in various cut regions over the sheet thickness and from cutting with a CO2 laser. The cutting velocity (100-50 mm/min) of sheet steel up to thicknesses of 10 mm with deep channeling, roughness parameters, hardness of the cut surface, which insignificantly (by ≈20%) exceeds the hardness of untreated steel, the phase structure of steel, and the scales of their varying inside metal are measured. The efficiency (≈3%) of precision cutting and the efficiency of transportation of radiation (25%) in large-caliber slot orifices in the "waveguide" mode are determined by the experimental data. The useful specific energy contribution of the laser radiation is w l = N l/( hbv) ≈ 2 × 1012 J/m2 for all studied thicknesses of sheet samples accurate to 20%. A qualitative model of the laser-oxygen precision cutting with deep channeling, which explains the cyclic and interrupting character of cutting and necessity of using oxygen as the cutting gas, is proposed.

[Isolation and purification of human blood plasma proteins able to form potassium channels in artificial bilayer lipid membrane].

PubMed

Venediktova, N I; Kuznetsov, K V; Gritsenko, E N; Gulidova, G P; Mironova, G D

2012-01-01

Protein fraction able to induce K(+)-selective transport across bilayer lipid membrane was isolated from human blood plasma with the use of the detergent and proteolytic enzyme-free method developed at our laboratory. After addition of the studied sample to the artificial membrane in the presence of 100 mM KCl, a discrete current change was observed. No channel activity was recorded in the presence of calcium and sodium ions. Channel forming activity of fraction was observed only in the presence of K+. Using a threefold gradient of KCl in the presence of studied proteins the potassium-selective potential balanced by voltage of -29 mV was registered. This value is very close to the theoretical Nernst potential in this case. This means that the examined ion channel is cation-selective. According to data obtained with MS-MALDI-TOF/TOF and database NCBI three protein components were identified in isolated researched sample.

Compatibility of the Space Station Freedom life sciences research centrifuge with microgravity requirements

NASA Technical Reports Server (NTRS)

Hasha, Martin D.

1990-01-01

NASA is developing a Life Sciences Centrifuge Facility for Space Station Freedom. In includes a 2.5-meter artificial gravity Bioresearch Centrifuge (BC), which is perhaps the most critical single element in the life sciences space research program. It rotates continuously at precise selectable rates, and utilizes advanced reliable technologies to reduce vibrations. Three disturbance types are analyzed using a current Space Station Freedom dynamic model in the 0.0 to 5.0 Hz range: sinusoidal, random, and transient. Results show that with proper selection of proven design techniques, BC vibrations are compatible with requirements.

Recent progress in tungsten oxides based memristors and their neuromorphological applications

NASA Astrophysics Data System (ADS)

Qu, Bo; Younis, Adnan; Chu, Dewei

2016-09-01

The advance in conventional silicon based semiconductor industry is now becoming indeterminacy as it still along the road of Moore's Law and concomitant problems associated with it are the emergence of a number of practical issues such as short channel effect. In terms of memory applications, it is generally believed that transistors based memory devices will approach to their scaling limits up to 2018. Therefore, one of the most prominent challenges today in semiconductor industry is the need of a new memory technology which is able to combine the best characterises of current devices. The resistive switching memories which are regarded as "memristors" thus gain great attentions thanks to their specific nonlinear electrical properties. More importantly, their behaviour resembles with the transmission characteristic of synapse in biology. Therefore, the research of synapses biomimetic devices based on memristor will certainly bring a great research prospect in studying synapse emulation as well as building artificial neural networks. Tungsten oxides (WO x ) exhibits many essential characteristics as a great candidate for memristive devices including: accredited endurance (over 105 cycles), stoichiometric flexibility, complimentary metal-oxide-semiconductor (CMOS) process compatibility and configurable properties including non-volatile rectification, memorization and learning functions. Herein, recent progress on Tungsten oxide based materials and its associating memory devices had been reviewed. The possible implementation of this material as a bio-inspired artificial synapse is also highlighted. The penultimate section summaries the current research progress for tungsten oxide based biological synapses and end up with several proposals that have been suggested for possible future developments.

24 CFR 1710.115 - Subdivision characteristics and climate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... erosion, sedimentation or periodic flooding throughout the subdivision? (2) If there is a program... seeding in areas of heavy grading or cut and fill along with the construction of diversion channels, ditches, outlet channels, waterway stabilizers and sediment control basins.) (f) Nuisances. Are there any...

24 CFR 1710.115 - Subdivision characteristics and climate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... erosion, sedimentation or periodic flooding throughout the subdivision? (2) If there is a program... seeding in areas of heavy grading or cut and fill along with the construction of diversion channels, ditches, outlet channels, waterway stabilizers and sediment control basins.) (f) Nuisances. Are there any...

Prediction of channel degradation rates in urbanizing watersheds

USDA-ARS?s Scientific Manuscript database

In urbanizing watersheds, as land use changes, and storm sewers and impervious surfaces are increased, both the frequency and magnitude of discharge increase, resulting in stream channel down-cutting and widening and related loss of structures and engineering works. A simple model for assessing the ...

Effects of cutting parameters and machining environments on surface roughness in hard turning using design of experiment

NASA Astrophysics Data System (ADS)

Mia, Mozammel; Bashir, Mahmood Al; Dhar, Nikhil Ranjan

2016-07-01

Hard turning is gradually replacing the time consuming conventional turning process, which is typically followed by grinding, by producing surface quality compatible to grinding. The hard turned surface roughness depends on the cutting parameters, machining environments and tool insert configurations. In this article the variation of the surface roughness of the produced surfaces with the changes in tool insert configuration, use of coolant and different cutting parameters (cutting speed, feed rate) has been investigated. This investigation was performed in machining AISI 1060 steel, hardened to 56 HRC by heat treatment, using coated carbide inserts under two different machining environments. The depth of cut, fluid pressure and material hardness were kept constant. The Design of Experiment (DOE) was performed to determine the number and combination sets of different cutting parameters. A full factorial analysis has been performed to examine the effect of main factors as well as interaction effect of factors on surface roughness. A statistical analysis of variance (ANOVA) was employed to determine the combined effect of cutting parameters, environment and tool configuration. The result of this analysis reveals that environment has the most significant impact on surface roughness followed by feed rate and tool configuration respectively.

Fluid flow monitoring device

DOEpatents

McKay, M.D.; Sweeney, C.E.; Spangler, B.S. Jr.

1993-11-30

A flow meter and temperature measuring device are described comprising a tube with a body centered therein for restricting flow and a sleeve at the upper end of the tube to carry several channels formed longitudinally in the sleeve to the appropriate axial location where they penetrate the tube to allow pressure measurements and temperature measurements with thermocouples. The high pressure measurement is made using a channel penetrating the tube away from the body and the low pressure measurement is made at a location at the widest part of the body. An end plug seals the end of the device and holes at its upper end allow fluid to pass from the interior of the tube into a plenum. The channels are made by cutting grooves in the sleeve, the grooves widened at the surface of the sleeve and then a strip of sleeve material is welded to the grooves closing the channels. Preferably the sleeve is packed with powdered graphite before cutting the grooves and welding the strips. 7 figures.

Multileg Heat-Pipe Evaporator

NASA Technical Reports Server (NTRS)

Alario, J. P.; Haslett, R. A.

1986-01-01

Parallel pipes provide high heat flow from small heat exchanger. Six parallel heat pipes extract heat from overlying heat exchanger, forming evaporator. Vapor channel in pipe contains wick that extends into screen tube in liquid channel. Rods in each channel hold wick and screen tube in place. Evaporator compact rather than extended and more compatible with existing heat-exchanger geometries. Prototype six-pipe evaporator only 0.3 m wide and 0.71 m long. With ammonia as working fluid, transports heat to finned condenser at rate of 1,200 W.

Fibre laser cutting stainless steel: Fluid dynamics and cut front morphology

NASA Astrophysics Data System (ADS)

Pocorni, Jetro; Powell, John; Deichsel, Eckard; Frostevarg, Jan; Kaplan, Alexander F. H.

2017-01-01

In this paper the morphology of the laser cut front generated by fibre lasers was investigated by observation of the 'frozen' cut front, additionally high speed imaging (HSI) was employed to study the fluid dynamics on the cut front while cutting. During laser cutting the morphology and flow properties of the melt film on the cut front affect cut quality parameters such as cut edge roughness and dross (residual melt attached to the bottom of the cut edge). HSI observation of melt flow down a laser cutting front using standard cutting parameters is experimentally problematic because the cut front is narrow and surrounded by the kerf walls. To compensate for this, artificial parameters are usually chosen to obtain wide cut fronts which are unrepresentative of the actual industrial process. This paper presents a new experimental cutting geometry which permits HSI of the laser cut front using standard, commercial parameters. These results suggest that the cut front produced when cutting medium section (10 mm thick) stainless steel with a fibre laser and a nitrogen assist gas is covered in humps which themselves are covered by a thin layer of liquid. HSI observation and theoretical analysis reveal that under these conditions the humps move down the cut front at an average speed of approximately 0.4 m/s while the covering liquid flows at an average speed of approximately 1.1 m/s, with an average melt depth at the bottom of the cut zone of approximately 0.17 mm.

Sample mounting and transfer for coupling an ultrahigh vacuum variable temperature beetle scanning tunneling microscope with conventional surface probes

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

Nafisi, Kourosh; Ranau, Werner; Hemminger, John C.

2001-01-01

We present a new ultrahigh vacuum (UHV) chamber for surface analysis and microscopy at controlled, variable temperatures. The new instrument allows surface analysis with Auger electron spectroscopy, low energy electron diffraction, quadrupole mass spectrometer, argon ion sputtering gun, and a variable temperature scanning tunneling microscope (VT-STM). In this system, we introduce a novel procedure for transferring a sample off a conventional UHV manipulator and onto a scanning tunneling microscope in the conventional ''beetle'' geometry, without disconnecting the heating or thermocouple wires. The microscope, a modified version of the Besocke beetle microscope, is mounted on a 2.75 in. outer diameter UHVmore » flange and is directly attached to the base of the chamber. The sample is attached to a tripod sample holder that is held by the main manipulator. Under UHV conditions the tripod sample holder can be removed from the main manipulator and placed onto the STM. The VT-STM has the capability of acquiring images between the temperature range of 180--500 K. The performance of the chamber is demonstrated here by producing an ordered array of island vacancy defects on a Pt(111) surface and obtaining STM images of these defects.« less

A cryogen-free low temperature scanning tunneling microscope capable of inelastic electron tunneling spectroscopy.

PubMed

Zhang, Shuai; Huang, Di; Wu, Shiwei

2016-06-01

The design and performance of a cryogen-free low temperature scanning tunneling microscope (STM) housed in ultrahigh vacuum (UHV) are reported. The cryogen-free design was done by directly integrating a Gifford-McMahon cycle cryocooler to a Besocke-type STM, and the vibration isolation was achieved by using a two-stage rubber bellow between the cryocooler and a UHV-STM interface with helium exchange gas cooling. A base temperature of 15 K at the STM was achieved, with a possibility to further decrease by using a cryocooler with higher cooling power and adding additional low temperature stage under the exchange gas interface. Atomically sharp STM images and high resolution dI/dV spectra on various samples were demonstrated. Furthermore, we reported the inelastic tunneling spectroscopy on a single carbon monoxide molecule adsorbed on Ag(110) surface with a cryogen-free STM for the first time. Being totally cryogen-free, the system not only saves the running cost significantly but also enables uninterrupted data acquisitions and variable temperature measurements with much ease. In addition, the system is capable of coupling light to the STM junction by a pair of lens inside the UHV chamber. We expect that these enhanced capabilities could further broaden our views to the atomic-scale world.

A cryogen-free low temperature scanning tunneling microscope capable of inelastic electron tunneling spectroscopy

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

Zhang, Shuai; Huang, Di; Wu, Shiwei, E-mail: swwu@fudan.edu.cn

The design and performance of a cryogen-free low temperature scanning tunneling microscope (STM) housed in ultrahigh vacuum (UHV) are reported. The cryogen-free design was done by directly integrating a Gifford-McMahon cycle cryocooler to a Besocke-type STM, and the vibration isolation was achieved by using a two-stage rubber bellow between the cryocooler and a UHV-STM interface with helium exchange gas cooling. A base temperature of 15 K at the STM was achieved, with a possibility to further decrease by using a cryocooler with higher cooling power and adding additional low temperature stage under the exchange gas interface. Atomically sharp STM imagesmore » and high resolution dI/dV spectra on various samples were demonstrated. Furthermore, we reported the inelastic tunneling spectroscopy on a single carbon monoxide molecule adsorbed on Ag(110) surface with a cryogen-free STM for the first time. Being totally cryogen-free, the system not only saves the running cost significantly but also enables uninterrupted data acquisitions and variable temperature measurements with much ease. In addition, the system is capable of coupling light to the STM junction by a pair of lens inside the UHV chamber. We expect that these enhanced capabilities could further broaden our views to the atomic-scale world.« less

Channel coding/decoding alternatives for compressed TV data on advanced planetary missions.

NASA Technical Reports Server (NTRS)

Rice, R. F.

1972-01-01

The compatibility of channel coding/decoding schemes with a specific TV compressor developed for advanced planetary missions is considered. Under certain conditions, it is shown that compressed data can be transmitted at approximately the same rate as uncompressed data without any loss in quality. Thus, the full gains of data compression can be achieved in real-time transmission.

Organic core-sheath nanowire artificial synapses with femtojoule energy consumption.

PubMed

Xu, Wentao; Min, Sung-Yong; Hwang, Hyunsang; Lee, Tae-Woo

2016-06-01

Emulation of biological synapses is an important step toward construction of large-scale brain-inspired electronics. Despite remarkable progress in emulating synaptic functions, current synaptic devices still consume energy that is orders of magnitude greater than do biological synapses (~10 fJ per synaptic event). Reduction of energy consumption of artificial synapses remains a difficult challenge. We report organic nanowire (ONW) synaptic transistors (STs) that emulate the important working principles of a biological synapse. The ONWs emulate the morphology of nerve fibers. With a core-sheath-structured ONW active channel and a well-confined 300-nm channel length obtained using ONW lithography, ~1.23 fJ per synaptic event for individual ONW was attained, which rivals that of biological synapses. The ONW STs provide a significant step toward realizing low-energy-consuming artificial intelligent electronics and open new approaches to assembling soft neuromorphic systems with nanometer feature size.

One-dimensional pressure transfer models for acoustic-electric transmission channels

NASA Astrophysics Data System (ADS)

Wilt, K. R.; Lawry, T. J.; Scarton, H. A.; Saulnier, G. J.

2015-09-01

A method for modeling piezoelectric-based ultrasonic acoustic-electric power and data transmission channels is presented. These channels employ piezoelectric disk transducers to convey signals across a series of physical layers using ultrasonic waves. This model decomposes the mechanical pathway of the signal into individual ultrasonic propagation layers which are generally independent of the layer's adjacent domains. Each layer is represented by a two-by-two traveling pressure wave transfer matrix which relates the forward and reverse pressure waves on one side of the layer to the pressure waves on the opposite face, where each face is assumed to be in contact with a domain of arbitrary reference acoustic impedance. A rigorous implementation of ultrasonic beam spreading is introduced and implemented within applicable domains. Compatible pressure-wave models for piezoelectric transducers are given, which relate the electric voltage and current interface of the transducer to the pressure waves on one mechanical interface while also allowing for passive acoustic loading of the secondary mechanical interface. It is also shown that the piezoelectric model's electrical interface is compatible with transmission line parameters (ABCD-parameters), allowing for connection of electronic components and networks. The model is shown to be capable of reproducing the behavior of realistic physical channels.

Verifying success of artificial spawning reefs in the St. Clair-Detroit River System for lake sturgeon (Acipenser fulvescens Rafinesque, 1817)

USGS Publications Warehouse

Bouckaert, Emliy K.; Auer, Nancy A.; Roseman, Edward F.; James Boase,

2014-01-01

Lake sturgeon (Acipenser fulvescens) were historically abundant in the St. Clair – Detroit River System (SCDRS), a 160 km river/channel network. In the SCDRS, lake sturgeon populations have been negatively affected by the loss/degradation of natural spawning habitat. To address habitat loss for lake sturgeon and other species, efforts are underway to restore spawning substrate by constructing artificial reefs. The main objective of this study was to conduct post-construction monitoring of lake sturgeon egg deposition and larval emergence near two of these artificial reefs: Fighting Island Reef (FIR) in the Detroit River, and Middle Channel Reef in the St. Clair River. An additional site in the St. Clair River where lake sturgeon spawn on a coal clinker bed was also investigated. From 2010 to 2012, viable eggs and larvae were collected from all of these reefs, indicating that conditions are suitable for egg deposition, incubation, and larval emergence. In the St. Clair River, the results indicate the likelihood of other spawning sites upstream of these artificial reef sites.

Design of a 12 channel fm microwave receiver. [for satellite ground stations

NASA Technical Reports Server (NTRS)

Risch, C. O.; Rosenbaum, F. J.; Gregory, R. O.

1974-01-01

The design, fabrication, and performance of elements of a low cost FM microwave satellite ground station receiver is described. It is capable of accepting 12 contiguous color television equivalent bandwidth channels in the 11.72 to 12.2 GHz band. Each channel is 40 MHz wide and incorporates a 4 MHz guard band. The modulation format is wideband FM and the channels are frequency division multiplexed. Twelve independent CATV compatible baseband outputs are provided. The overall system specifications are first discussed, then consideration is given to the receiver subsystems and the signal branching network.

Choice: 36 band feature selection software with applications to multispectral pattern recognition

NASA Technical Reports Server (NTRS)

Jones, W. C.

1973-01-01

Feature selection software was developed at the Earth Resources Laboratory that is capable of inputting up to 36 channels and selecting channel subsets according to several criteria based on divergence. One of the criterion used is compatible with the table look-up classifier requirements. The software indicates which channel subset best separates (based on average divergence) each class from all other classes. The software employs an exhaustive search technique, and computer time is not prohibitive. A typical task to select the best 4 of 22 channels for 12 classes takes 9 minutes on a Univac 1108 computer.

Sequence genomic organization and expression of two channel catfish Ictalurus punctatus Ghrelin receptors

USDA-ARS?s Scientific Manuscript database

Two ghrelin receptor (GHS-R) genes were isolated from channel catfish tissue and a bacterial artificial chromosome (BAC) library. The two receptors were characterized by determining tissue distribution, ontogeny of receptor mRNA expression, and effects of exogenous homologous ghrelin administration ...

Influence of light and shoot development stage on leaf photosynthesis and carbohydrate status during the adventitious root formation in cuttings of Corylus avellana L.

PubMed Central

Tombesi, Sergio; Palliotti, Alberto; Poni, Stefano; Farinelli, Daniela

2015-01-01

Adventitious root formation in plant cuttings is influenced by many endogenous and environmental factors. Leaf photosynthesis during rooting of leafy cuttings in hard to root species can contribute to supply carbohydrates to the intensive metabolic processes related to adventious root formation. Light intensity during rooting is artificially kept low to decrease potential cutting desiccation, but can be limiting for photosynthetic activity. Furthermore, leafy cuttings collected from different part of the shoot can have a different ability to fuel adventitious root formation in cutting stem. The aim of this work was to determine the role of leaf photosynthesis on adventitious root formation in hazelnut (Corylus avellana L) (a hard-to-root specie) leafy cuttings and to investigate the possible influence of the shoot developmental stage on cutting rooting and survival in the post-rooting phase. Cutting rooting was closely related to carbohydrate content in cutting stems during the rooting process. Cutting carbohydrate status was positively influenced by leaf photosynthesis during rooting. Non-saturating light exposure of leafy cuttings can contribute to improve photosynthetic activity of leafy cuttings. Collection of cuttings from different part of the mother shoots influenced rooting percentage and this appear related to the different capability to concentrate soluble sugars in the cutting stem during rooting. Adventitious root formation depend on the carbohydrate accumulation at the base of the cutting. Mother shoot developmental stage and leaf photosynthesis appear pivotal factors for adventitious roots formation. PMID:26635821

Tantalus Fossae

NASA Technical Reports Server (NTRS)

2002-01-01

(Released 25 June 2002) The Science Tantalus Fossae is a set of long valleys on the eastern side of Alba Patera. These valleys are referred to as grabens and are formed by extension of the crust and faulting. When large amounts of pressure or tension are applied to rocks on timescales that are fast enough that the rock cannot respond by deforming, the rock breaks along faults. In the case of a graben, two parallel faults are formed by extension of the crust and the rock in between the faults drops downward into the space created by the extension. Numerous sets of grabens are visible in this THEMIS image, trending from north-northeast to south-southwest. Because the faults defining the graben are formed parallel to the direction of the applied stress, we know that extensional forces were pulling the crust apart in the west-northwest/east-southeast direction. The large number of grabens around Alba Patera is generally believed to be the result of extensional forces associated with the uplift of Alba Patera. Also visible in this image are a series of linearly aligned pits, called a pit chain. The pits are not the result of impact cratering, but are similar to sinkholes on Earth. Sinkholes are typically formed by the removal of rock (commonly limestone) underground by groundwater -- when enough rock is removed, the overlying rock becomes too heavy to be supported, and it collapses, forming a pit. Unlike sinkholes, however, the pit chains near Alba Patera were likely formed when empty underground lava tubes collapsed, accounting for the presence and alignment of many pits. Numerous channel features are also observed in the image, and follow the local topographic slope, which is downhill to the east-southeast. One of these, a long channel in the center of the image, nicely demonstrates the complex relations possible between geologic features. The geologist's rule of superposition says that a feature on top of (superposing) another feature, or cutting across another feature is younger than the feature it covers or cuts. In one location, the channel cuts across the somewhat subdued fault defining a graben (near the right side of the image), indicating that the channel was carved after the graben was formed. But in other places (near the center of the image), the channel is clearly cut by a large fault defining one of the grabens, indicating that some faulting was occurring after the channel was carved. These relationships can be observed throughout this image. By mapping out superposition relationships in detail, geologists can establish a complex sequence of events that occurred long ago. The Story The first thing that catches your eye in the image above is a string of round pits that are strewn dramatically on the surface. Although they may look like craters, nothing came hurtling in from the sky to make them. Instead, collapses along a lava tube have created this long dotted line on the Martian surface. The lava tube, a hollow feature beneath the surface, can't always withstand the weight from above, and so collapses in places, forming pits like the ones seen here. Throughout the rest of the image are a series of depressed valleys known as grabens that run roughly from the northeast to the southwest. They formed when the crust of the Martian surface was stretched so fast that it broke along faults. When that happened, the rock in between fell downward into the space created by the extension, creating the long subtle streaks of lowered terrain. They were probably created when Alba Patera, the shield volcano of this area, was elevated or 'uplifted' through tectonic forces. This area of long valleys is named after Tantalus, a king of ancient Lydia who, according to legend, betrayed the gods and was sent to Hades. In this subterranean place, he was forced to stand in water up to his chin underneath the branches of fruit trees. Every time he tried to drink, the water would recede, and every time he tried to eat, the boughs would move the fruit just out of reach. You can easily see where the word 'tantalize' comes from. Scientists are intrigued so much by the history of this area that they seek to understand its elusive past. Luckily, their interests are much more in reach than those of poor Tantalus. A number of channels in this image (running downhill from the west-northwest to the east-southeast) help them understand the chain of events that worked to create the compelling features in this region. Take a look at the channels close-up and see if you can tell whether the channels or the grabens happened first. A rule of thumb is that if one feature is on top of another or cuts across it, it is younger than the feature it covers or cuts. One of the channels in the center of the image is great to study. Toward the right side of the image, the channel cuts across a fault, indicating it formed before the graben. Follow the channel westward, however, and you'll see that a large fault cuts the channel, indicating that this graben formed after the channel. That probably means this criss-crossed region went through a seeming eternity of torture itself, as the land kept tearing and stretching, as channels were carved and recarved, as lava tubes formed and then finally collapsed, only to have their walls erode in further streaks as well.

CMOS-Compatible Fabrication for Photonic Crystal-Based Nanofluidic Structure.

PubMed

Peng, Wang; Chen, Youping; Ai, Wu; Zhang, Dailin; Song, Han; Xiong, Hui; Huang, Pengcheng

2017-12-01

Photonic crystal (PC)-based devices have been widely used since 1990s, while PC has just stepped into the research area of nanofluidic. In this paper, photonic crystal had been used as a complementary metal oxide semiconductors (CMOS) compatible part to create a nanofluidic structure. A nanofluidic structure prototype had been fabricated with CMOS-compatible techniques. The nanofluidic channels were sealed by direct bonding polydimethylsiloxane (PDMS) and the periodic gratings on photonic crystal structure. The PC was fabricated on a 4-in. Si wafer with Si 3 N 4 as the guided mode layer and SiO 2 film as substrate layer. The higher order mode resonance wavelength of PC-based nanofluidic structure had been selected, which can confine the enhanced electrical field located inside the nanochannel area. A design flow chart was used to guide the fabrication process. By optimizing the fabrication device parameters, the periodic grating of PC-based nanofluidic structure had a high-fidelity profile with fill factor at 0.5. The enhanced electric field was optimized and located within the channel area, and it can be used for PC-based nanofluidic applications with high performance.

GREAT II (Upper Mississippi River. Guttenberg, Iowa to Saverton, Missouri). Side Channel Work Group Appendix

DTIC Science & Technology

1980-12-01

is current during normal river stage. The graduations in this category are wide- spread, ranging frcm fast flowing watercourses with high banks to...channel category on the other. They may be former side channels that have been cut off, or that have only intermittent flows in them. They may be...navigation project certainly is a contributor by providing a deep channel and an abundance of beaches. Karaki and Van Hoften noted that small, fast

Single-channel in-ear-EEG detects the focus of auditory attention to concurrent tone streams and mixed speech

NASA Astrophysics Data System (ADS)

Fiedler, Lorenz; Wöstmann, Malte; Graversen, Carina; Brandmeyer, Alex; Lunner, Thomas; Obleser, Jonas

2017-06-01

Objective. Conventional, multi-channel scalp electroencephalography (EEG) allows the identification of the attended speaker in concurrent-listening (‘cocktail party’) scenarios. This implies that EEG might provide valuable information to complement hearing aids with some form of EEG and to install a level of neuro-feedback. Approach. To investigate whether a listener’s attentional focus can be detected from single-channel hearing-aid-compatible EEG configurations, we recorded EEG from three electrodes inside the ear canal (‘in-Ear-EEG’) and additionally from 64 electrodes on the scalp. In two different, concurrent listening tasks, participants (n  =  7) were fitted with individualized in-Ear-EEG pieces and were either asked to attend to one of two dichotically-presented, concurrent tone streams or to one of two diotically-presented, concurrent audiobooks. A forward encoding model was trained to predict the EEG response at single EEG channels. Main results. Each individual participants’ attentional focus could be detected from single-channel EEG response recorded from short-distance configurations consisting only of a single in-Ear-EEG electrode and an adjacent scalp-EEG electrode. The differences in neural responses to attended and ignored stimuli were consistent in morphology (i.e. polarity and latency of components) across subjects. Significance. In sum, our findings show that the EEG response from a single-channel, hearing-aid-compatible configuration provides valuable information to identify a listener’s focus of attention.

Craterlike structures on the laser cut surface

NASA Astrophysics Data System (ADS)

Shulyatyev, V. B.; Orishich, A. M.

2017-10-01

Analysis of the laser cut surface morphology remain topical. It is related with the fact that the surface roughness is the main index of the cut quality. The present paper deals with the experimental study of the relatively unstudied type of defects on the laser cut surface, dimples, or craters. According to the measurement results, amount of craters per unit of the laser cut surface area rises as the sheet thickness rises. The crater diameter rises together with the sheet thickness and distance from the upper sheet edge. The obtained data permit concluding that the defects like craters are observed predominantly in the case of thick sheets. The results agree with the hypothesis of crater formation as impact structures resulting from the melt drops getting on the cut channel walls upon separation from the cut front by the gas flow.

Electromagnetic Fields and Human Health: Fundamental and Applied Research. Proceeding of the International Conference (3rd) Held in Moscow and St. Petersburg, Russia, September 17-25 2002

DTIC Science & Technology

2002-10-28

repeatedly similar to those observed in a standard hatchery. In a series of seven replicates, eggs issued from artificially inseminated hens (200 x 106 spz...intercellular information channel leading to the negative con- sequences for the organism. Likely the magnet storms the artificial change of magnet field...biochemical reactions that can be affected by such pulses. We shall present data that shows an artificially contrived biochemical reaction, the

Long-distance quantum communication with atomic ensembles and linear optics.

PubMed

Duan, L M; Lukin, M D; Cirac, J I; Zoller, P

2001-11-22

Quantum communication holds promise for absolutely secure transmission of secret messages and the faithful transfer of unknown quantum states. Photonic channels appear to be very attractive for the physical implementation of quantum communication. However, owing to losses and decoherence in the channel, the communication fidelity decreases exponentially with the channel length. Here we describe a scheme that allows the implementation of robust quantum communication over long lossy channels. The scheme involves laser manipulation of atomic ensembles, beam splitters, and single-photon detectors with moderate efficiencies, and is therefore compatible with current experimental technology. We show that the communication efficiency scales polynomially with the channel length, and hence the scheme should be operable over very long distances.

Sedimentation rate and lateral migration of tidal channels in the Lagoon of Venice (Northern Italy)

NASA Astrophysics Data System (ADS)

Donnici, Sandra; Madricardo, Fantina; Serandrei-Barbero, Rossana

2017-11-01

Tidal channels are crucial for the functioning of highly valuable coastal environments, such as estuaries and lagoons. Their properties, however, are currently less understood than those of river systems. To elucidate their past behaviour, an extensive geophysical investigation was performed to reconstruct the evolution of channels and tidal surfaces in the central part of the Lagoon of Venice (Italy) over the past 5000 years. Comparing high-spatial-resolution acoustic data and sedimentary facies analyses of 41 cores, 29 of which were radiocarbon dated, revealed the sedimentation rates in different lagoonal environments and allowed the migration of two large meanders to be reconstructed. The average sedimentation rate of the study succession in the different sedimentary environments was 1.27 mm yr-1. The lateral migration rates were 13-23 m/century. This estimate is consistent with the lateral migration rates determined by comparing aerial photographs of recent channels. Comparing the buried channels with historical and current maps showed that, in general, the number of active channels is now reduced. Their morphology was sometimes simplified by artificial interventions. An understanding of the impact of the artificial interventions over time is useful for the management and conservation of tidal environments, particularly for the Lagoon of Venice, where management authorities are currently debating the possible deepening and rectification of large navigation channels.

Prediction of laser cutting heat affected zone by extreme learning machine

NASA Astrophysics Data System (ADS)

Anicic, Obrad; Jović, Srđan; Skrijelj, Hivzo; Nedić, Bogdan

2017-01-01

Heat affected zone (HAZ) of the laser cutting process may be developed based on combination of different factors. In this investigation the HAZ forecasting, based on the different laser cutting parameters, was analyzed. The main goal was to predict the HAZ according to three inputs. The purpose of this research was to develop and apply the Extreme Learning Machine (ELM) to predict the HAZ. The ELM results were compared with genetic programming (GP) and artificial neural network (ANN). The reliability of the computational models were accessed based on simulation results and by using several statistical indicators. Based upon simulation results, it was demonstrated that ELM can be utilized effectively in applications of HAZ forecasting.

Note: Mechanical in situ exfoliation of van der Waals materials

NASA Astrophysics Data System (ADS)

Pásztor, Á.; Scarfato, A.; Renner, Ch.

2017-07-01

Exfoliation, namely, the peeling of layered materials down to a single unit-cell thin foil, opens promising avenues to fabricate novel electronic materials. New properties and original functionalities emerge in the single and few layer configurations of a number of layered compounds, in particular in transition metal dichalcogenides. However, many of these thin exfoliated materials are very sensitive to ambient conditions impeding the exploration of this new and fascinating parameter space. Here we describe a method of mechanical exfoliation in ultra-high vacuum (UHV). This technique is easily adaptable to any UHV system and allows preparing and studying air sensitive nanoflakes in situ. We present the basic design and proof-of-concept scanning tunneling microscopy imaging of VSe2 nanoflakes.

Simulation and experimental research on micro-channel for detecting cell status in bio-artificial liver.

PubMed

Wu, Changzhe; Cao, Yue; Huo, Xiaolin; Li, Ming

2015-01-01

Bioartificial liver support system (BALSS) based on culturing hepatocytes is an important research field for the treatment of acute liver failure. It is necessary to monitor the state of liver cell functions during the treatment of BALSS in order to guide clinical treatment. To design a micro-channel chip to achieve flash mixing for timely detection of liver cell status in bioreactors and improving liver cells growth environment to ensure the efficacy of the bio-artificial liver support system. Alanine aminotransferase (ALT) and Urea are chosen as detection indicators to reflect the degree of liver cell injury and the detoxification function. A diamond tandem structure micro-channel is designed and optimized to achieve the efficient mixing of serum and ALT or Urea reagent. The simulation and experimental results show that the diamond tandem structure micro-channel can significantly improve the mixing efficiency and meet the online detecting requirements. The easily controllable diamond tandem structure micro-channel combines the advantages of active and passive mixer and can effectively mix the serum and ALT or Urea reagent. It lays the foundation for online monitoring of liver cells and will help to improve the viability of liver cell in the bioreactor.

Application of double-layered skin phantoms for optical flow imaging during laser tattoo treatments

NASA Astrophysics Data System (ADS)

Lee, Byeong-il; Song, Woosub; Kim, Hyejin; Kang, Hyun Wook

2016-05-01

The feasible application of double-layered skin phantoms was evaluated to identify artificial blood flow with a Doppler optical coherence tomography (DOCT) system for laser tattoo treatments. Polydimethylsiloxane (PDMS) was used to fabricate the artificial phantoms with flow channels embedded. A double-integrating sphere system with an inverse adding-doubling method quantified both the absorption and the reduced scattering coefficients for epidermis and dermis phantoms. Both OCT and caliper measurements confirmed the double-layered phantom structure (epidermis = 136 ± 17 µm vs. dermis = 3.0 ± 0.1 mm). The DOCT method demonstrated that high flow rates were associated with high image contrast, visualizing the position and the shape of the flow channel. Application of the channel-embedded skin phantoms in conjunction with DOCT can be a reliable technique to assess dynamic variations in the blood flow during and after laser tattoo treatments.

Evaluating the flood tolerance of bottomland hardwood artificial reproduction

Treesearch

John M. Kabrick; Daniel C. Dey; Jonathan R. Motsinger

2007-01-01

We experimentally compared the survival and growth after flooding of six bottomland species: eastern cottonwood (cuttings) (Populus deltoides Bartr. Ex Marsh.), pin oak (Quercus palustris Muenchh.), swamp white oak (Q. bicolor Willd.), bur oak (Q. macrocarpa Michx.), black walnut (...

50 CFR 648.148 - Special management zones.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Black Sea Bass Fishery § 648.148 Special management zones. The recipient of a U.S. Army Corps of... purposes of fishing may request that an area surrounding and including the site be designated by the MAFMC... fishing gear that are not compatible with the intent of the artificial reef or fish attraction device or...

Identifying new lignin bioengineering targets: impact of epicatechin, quercetin glycoside, and gallate derivatives on the lignification and fermentation of maize cell walls

USDA-ARS?s Scientific Manuscript database

Apoplastic targeting of secondary metabolites compatible with monolignol polymerization may provide new avenues for designing lignins that are less inhibitory toward fiber fermentation. To identify suitable monolignol substitutes, we artificially lignified maize cell walls with normal monolignols pl...

30 CFR 75.1910 - Nonpermissible diesel-powered equipment; electrical system design and performance requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... simultaneously and perform virtually the same duty; (f) Each ungrounded conductor must have insulation compatible with the impressed voltage. Insulation materials must be resistant to deterioration from engine heat... damaging wires, cables, or conduits by cutting or abrasion. The insulation of the cables within a battery...

30 CFR 75.1910 - Nonpermissible diesel-powered equipment; electrical system design and performance requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... simultaneously and perform virtually the same duty; (f) Each ungrounded conductor must have insulation compatible with the impressed voltage. Insulation materials must be resistant to deterioration from engine heat... damaging wires, cables, or conduits by cutting or abrasion. The insulation of the cables within a battery...

30 CFR 75.1910 - Nonpermissible diesel-powered equipment; electrical system design and performance requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... simultaneously and perform virtually the same duty; (f) Each ungrounded conductor must have insulation compatible with the impressed voltage. Insulation materials must be resistant to deterioration from engine heat... damaging wires, cables, or conduits by cutting or abrasion. The insulation of the cables within a battery...

30 CFR 75.1910 - Nonpermissible diesel-powered equipment; electrical system design and performance requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... simultaneously and perform virtually the same duty; (f) Each ungrounded conductor must have insulation compatible with the impressed voltage. Insulation materials must be resistant to deterioration from engine heat... damaging wires, cables, or conduits by cutting or abrasion. The insulation of the cables within a battery...

The effects of railway transportation on the enrichment of heavy metals in the artificial soil on railway cut slopes.

PubMed

Chen, Zhaoqiong; Wang, KeXiu; Ai, Ying Wei; Li, Wei; Gao, Hongying; Fang, Chen

2014-02-01

Heavy metal contamination in the artificial soils on the railway cut slopes may have great influence on the revegetation of the cut slopes. The purpose of this study was to assess the variation of heavy metal contamination levels with railway operation time and analyze their possible resources. A total of 100 soil samples from four cut slopes, which were affected by railway transportation for different years, were analyzed for metal pollution (Cd, Pb, Cr, Cu, Zn, Fe). The concentrations of Cd, Pb showed increasing trend with increasing operation time of railways, while such trend was not found in Cr, Cu, Zn, Fe. According to the soil quality standard of China, Cd was considered to have considerable contamination, while Pb has less, but Cr, Cu, Zn, Fe have none. Moreover, cadmium exhibited remarkably higher levels rather than those reported in other studies. Enrichment factors and ecological index showed that Cd and Pb showed a moderate enrichment and a considerable ecological risk in most of the soil samples. The results of descriptive statistic, principal component analysis, cluster analysis and correlation analysis were totally consistent with each other. Their results revealed that Cr, Cu, Zn and Fe had common origins, and they may come from natural resources. While Cd and Pb were significantly influenced by railway transportation, leaked cargos, fuel combustion, the use of lubricate oils and sleeper impregnation oils during railway transportation may be their main resources.

Longitudinal Variation in Paleo-channel Complex Geometry and Associated Fill: Offshore South Carolina

NASA Astrophysics Data System (ADS)

Long, A. M.; Hill, J. C.

2017-12-01

In northeastern South Carolina, several shallow (<25 m deep) paleo-channel complexes have previously been interpreted as the result of the southward migration of the ancestral Pee Dee River system along the southern limb of the Cape Fear Arch since the Pliocene. These paleo-channel complexes can be traced 80 km across the continental shelf via Boomer and Chirp subbottom data. The Murrells Inlet paleo-channel complex is the most well imaged offshore; and this data coverage provides an opportunity for a detailed seismic stratigraphic interpretation and analysis of downstream variability. Initial observations from this case study indicate that inner shelf incisions, where bedrock is folded and faulted, tend to be shallow with numerous channels, while the incisions across the middle shelf appear to be deeper and contains larger, more sinuous channels that are cut into broadly tilted strata with a gentle south-southeastward dip. This suggests the geometry and spatial distribution of the incisions were a function of the inherited fabric of the underlying basement, which created local deflection and areas of aggradation and degradation. The inner shelf paleo-channel complex fill is dominated by fluvial cut and fill seismic facies, while the middle shelf contains a wide variety of seismic facies (i.e. transparent, layered, chaotic, etc). This overall longitudinal fill pattern is most likely due to each location's general proximity to base level. The variation in the cut and fill seismic facies may be driven by substantial changes in discharge, driven locally by the joining of another major river or by climatic changes in the drainage basin. There also appears to be preferential reoccupation of previously filled paleo-channels, as the basement in this region is Tertiary and Cretaceous carbonates and siliciclastic rocks that are more resistant to erosion. The most recent occupation in any given paleo-channel tends to be on the southern margin, which may imply tectonic forcing from the uplift of the Cape Fear Arch. Preliminary results from this case study suggest that first order controls on the position and geometry of the paleo-channel complexes appears to be largely allogenic (i.e. tectonic and base level driven), while the depositional history of the fill may have been a mix of autogenic and allogenic processes.

Surfing gravitational waves: can bigravity survive growing tensor modes?

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

Amendola, Luca; Könnig, Frank; Martinelli, Matteo

The theory of bigravity offers one of the simplest possibilities to describe a massive graviton while having self-accelerating cosmological solutions without a cosmological constant. However, it has been shown recently that bigravity is affected by early-time fast growing modes on the tensor sector. Here we argue that we can only trust the linear analysis up to when perturbations are in the linear regime and use a cut-off to stop the growing of the metric perturbations. This analysis, although more consistent, still leads to growing tensor modes that are unacceptably large for the theory to be compatible with measurements of themore » cosmic microwave background (CMB), both in temperature and polarization spectra. In order to suppress the growing modes and make the model compatible with CMB spectra, we find it necessary to either fine-tune the initial conditions, modify the theory or set the cut-off for the tensor perturbations of the second metric much lower than unity. Initial conditions such that the growing mode is sufficiently suppresed can be achieved in scenarios in which inflation ends at the GeV scale.« less

Deriving magnetite nanostructures from natural resources and investigation of its erythrocyte compatibility

NASA Astrophysics Data System (ADS)

Chitra, S.; Bargavi, P.; Durgalakshmi, D.; Balasubramaniam, M.; Rajashree, P.; Balakumar, S.

2018-04-01

Nanostructured Iron oxide nanoparticles are being used for various biomedical applications such as Magnetic Resonance Imaging, Drug Delivery, Hyperthermia, Photo-ablation therapy and Biosensors as it exhibits tremendous biocompatibility. These magnetic materials are abundant, are available in natural resources such as sand, rock and various plants. In the present investigation, magnetic materials were separated from beach sand using external magnet and studied the properties of mineral magnetite, and it exhibits well-known compatibility with erythrocytes. Mineral magnetite derived from natural resources can demonstrate better biocompatibility and in addition, it cuts down the necessity of going towards highly expensive iron sources.

Artificial insect wings with biomimetic wing morphology and mechanical properties.

PubMed

Liu, Zhiwei; Yan, Xiaojun; Qi, Mingjing; Zhu, Yangsheng; Huang, Dawei; Zhang, Xiaoyong; Lin, Liwei

2017-09-26

The pursuit of a high lift force for insect-scale flapping-wing micro aerial vehicles (FMAVs) requires that their artificial wings possess biomimetic wing features which are close to those of their natural counterpart. In this work, we present both fabrication and testing methods for artificial insect wings with biomimetic wing morphology and mechanical properties. The artificial cicada (Hyalessa maculaticollis) wing is fabricated through a high precision laser cutting technique and a bonding process of multilayer materials. Through controlling the shape of the wing venation, the fabrication method can achieve three-dimensional wing architecture, including cambers or corrugations. Besides the artificial cicada wing, the proposed fabrication method also shows a promising versatility for diverse wing types. Considering the artificial cicada wing's characteristics of small size and light weight, special mechanical testing systems are designed to investigate its mechanical properties. Flexural stiffness, maximum deformation rate and natural frequency are measured and compared with those of its natural counterpart. Test results reveal that the mechanical properties of the artificial cicada wing depend strongly on its vein thickness, which can be used to optimize an artificial cicada wing's mechanical properties in the future. As such, this work provides a new form of artificial insect wings which can be used in the field of insect-scale FMAVs.

Electromagnetic fields (UHF) increase voltage sensitivity of membrane ion channels; possible indication of cell phone effect on living cells.

PubMed

Ketabi, N; Mobasheri, H; Faraji-Dana, R

2015-03-01

The effects of ultra high frequency (UHF) nonionizing electromagnetic fields (EMF) on the channel activities of nanopore forming protein, OmpF porin, were investigated. The voltage clamp technique was used to study the single channel activity of the pore in an artificial bilayer in the presence and absence of the electromagnetic fields at 910 to 990 MHz in real time. Channel activity patterns were used to address the effect of EMF on the dynamic, arrangement and dielectric properties of water molecules, as well as on the hydration state and arrangements of side chains lining the channel barrel. Based on the varied voltage sensitivity of the channel at different temperatures in the presence and absence of EMF, the amount of energy transferred to nano-environments of accessible groups was estimated to address the possible thermal effects of EMF. Our results show that the effects of EMF on channel activities are frequency dependent, with a maximum effect at 930 MHz. The frequency of channel gating and the voltage sensitivity is increased when the channel is exposed to EMF, while its conductance remains unchanged at all frequencies applied. We have not identified any changes in the capacitance and permeability of membrane in the presence of EMF. The effect of the EMF irradiated by cell phones is measured by Specific Absorption Rate (SAR) in artificial model of human head, Phantom. Thus, current approach applied to biological molecules and electrolytes might be considered as complement to evaluate safety of irradiating sources on biological matter at molecular level.

Integrated Force Method Solution to Indeterminate Structural Mechanics Problems

NASA Technical Reports Server (NTRS)

Patnaik, Surya N.; Hopkins, Dale A.; Halford, Gary R.

2004-01-01

Strength of materials problems have been classified into determinate and indeterminate problems. Determinate analysis primarily based on the equilibrium concept is well understood. Solutions of indeterminate problems required additional compatibility conditions, and its comprehension was not exclusive. A solution to indeterminate problem is generated by manipulating the equilibrium concept, either by rewriting in the displacement variables or through the cutting and closing gap technique of the redundant force method. Compatibility improvisation has made analysis cumbersome. The authors have researched and understood the compatibility theory. Solutions can be generated with equal emphasis on the equilibrium and compatibility concepts. This technique is called the Integrated Force Method (IFM). Forces are the primary unknowns of IFM. Displacements are back-calculated from forces. IFM equations are manipulated to obtain the Dual Integrated Force Method (IFMD). Displacement is the primary variable of IFMD and force is back-calculated. The subject is introduced through response variables: force, deformation, displacement; and underlying concepts: equilibrium equation, force deformation relation, deformation displacement relation, and compatibility condition. Mechanical load, temperature variation, and support settling are equally emphasized. The basic theory is discussed. A set of examples illustrate the new concepts. IFM and IFMD based finite element methods are introduced for simple problems.

Some conservative estimates in quantum cryptography

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

Molotkov, S. N.

2006-08-15

Relationship is established between the security of the BB84 quantum key distribution protocol and the forward and converse coding theorems for quantum communication channels. The upper bound Q{sub c} {approx} 11% on the bit error rate compatible with secure key distribution is determined by solving the transcendental equation H(Q{sub c})=C-bar({rho})/2, where {rho} is the density matrix of the input ensemble, C-bar({rho}) is the classical capacity of a noiseless quantum channel, and H(Q) is the capacity of a classical binary symmetric channel with error rate Q.

Multi-leg heat pipe evaporator

NASA Technical Reports Server (NTRS)

Alario, J. P.; Haslett, R. A. (Inventor)

1986-01-01

A multileg heat pipe evaporator facilitates the use and application of a monogroove heat pipe by providing an evaporation section which is compact in area and structurally more compatible with certain heat exchangers or heat input apparatus. The evaporation section of a monogroove heat pipe is formed by a series of parallel legs having a liquid and a vapor channel and a communicating capillary slot therebetween. The liquid and vapor channels and interconnecting capillary slots of the evaporating section are connected to the condensing section of the heat pipe by a manifold connecting liquid and vapor channels of the parallel evaporation section legs with the corresponding liquid and vapor channels of the condensing section.

Program on application of communications satellites to educational development: Design of a 12 channel FM microwave receiver. [color television from communication satellites

NASA Technical Reports Server (NTRS)

Risch, C. O.; Rosenbaum, F. J.; Gregory, R. O.

1974-01-01

The design, fabrication, and performance of elements of a low cost FM microwave satellite ground station receiver is described. It is capable of accepting 12 contiguous color television equivalent bandwidth channels in the 11.72 to 12.2 GHz band. Each channel is 40 MHz wide and incorporates a 4 MHz guard band. The modulation format is wideband FM and the channels are frequency division multiplexed. Twelve independent CATV compatible baseband outputs are provided. The overall system specifications are first discussed, then consideration is given to the receiver subsystems and the signal branching network.

Self-aligned blocking integration demonstration for critical sub-40nm pitch Mx level patterning

NASA Astrophysics Data System (ADS)

Raley, Angélique; Mohanty, Nihar; Sun, Xinghua; Farrell, Richard A.; Smith, Jeffrey T.; Ko, Akiteru; Metz, Andrew W.; Biolsi, Peter; Devilliers, Anton

2017-04-01

Multipatterning has enabled continued scaling of chip technology at the 28nm node and beyond. Selfaligned double patterning (SADP) and self-aligned quadruple patterning (SAQP) as well as Litho- Etch/Litho-Etch (LELE) iterations are widely used in the semiconductor industry to enable patterning at sub 193 immersion lithography resolutions for layers such as FIN, Gate and critical Metal lines. Multipatterning requires the use of multiple masks which is costly and increases process complexity as well as edge placement error variation driven mostly by overlay. To mitigate the strict overlay requirements for advanced technology nodes (7nm and below), a self-aligned blocking integration is desirable. This integration trades off the overlay requirement for an etch selectivity requirement and enables the cut mask overlay tolerance to be relaxed from half pitch to three times half pitch. Selfalignement has become the latest trend to enable scaling and self-aligned integrations are being pursued and investigated for various critical layers such as contact, via, metal patterning. In this paper we propose and demonstrate a low cost flexible self-aligned blocking strategy for critical metal layer patterning for 7nm and beyond from mask assembly to low -K dielectric etch. The integration is based on a 40nm pitch SADP flow with 2 cut masks compatible with either cut or block integration and employs dielectric films widely used in the back end of the line. As a consequence this approach is compatible with traditional etch, deposition and cleans tools that are optimized for dielectric etches. We will review the critical steps and selectivities required to enable this integration along with bench-marking of each integration option (cut vs. block).

Application of a soft computing technique in predicting the percentage of shear force carried by walls in a rectangular channel with non-homogeneous roughness.

PubMed

Khozani, Zohreh Sheikh; Bonakdari, Hossein; Zaji, Amir Hossein

2016-01-01

Two new soft computing models, namely genetic programming (GP) and genetic artificial algorithm (GAA) neural network (a combination of modified genetic algorithm and artificial neural network methods) were developed in order to predict the percentage of shear force in a rectangular channel with non-homogeneous roughness. The ability of these methods to estimate the percentage of shear force was investigated. Moreover, the independent parameters' effectiveness in predicting the percentage of shear force was determined using sensitivity analysis. According to the results, the GP model demonstrated superior performance to the GAA model. A comparison was also made between the GP program determined as the best model and five equations obtained in prior research. The GP model with the lowest error values (root mean square error ((RMSE) of 0.0515) had the best function compared with the other equations presented for rough and smooth channels as well as smooth ducts. The equation proposed for rectangular channels with rough boundaries (RMSE of 0.0642) outperformed the prior equations for smooth boundaries.

Tension Behaviour on the Connection of the Cold-Formed Cut-Curved Steel Channel Section

NASA Astrophysics Data System (ADS)

Sani, Mohd Syahrul Hisyam Mohd; Muftah, Fadhluhartini; Fakri Muda, Mohd; Siang Tan, Cher

2017-08-01

Cold-formed steel (CFS) are utilised as a non-structural and structural element in construction activity especially a residential house and small building roof truss system. CFS with a lot of advantages and some of disadvantages such as buckling that must be prevented for roof truss production are being studied equally. CFS was used as a top chord of the roof truss system which normally a slender section is dramatically influenced to buckling failure and instability of the structure. So, the curved section is produced for a top chord for solving the compression member of the roof truss. Besides, there are lacked of design and production information about the CFS curved channel section. In the study, the CFS is bent by using a cut-curved method because of ease of production, without the use of skilled labour and high cost machine. The tension behaviour of the strengthening method of cut-curved or could be recognised as a connection of the cut-curved section was tested and analysed. There are seven types of connection was selected. From the testing and observation, it is shown the specimen with full weld along the cut section and adds with flange element plate with two self-drilling screws (F7A) was noted to have a higher value of ultimate load. Finally, there are three alternative methods of connection for CFS cut-curved that could be a reference for a contractor and further design.

Photoelectron emission yield experiments on evolution of sub-gap states in amorphous In-Ga-Zn-O thin films with post deposition hydrogen treatment

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

Hayashi, Kazushi, E-mail: hayashi.kazushi@kobelco.com; Hino, Aya; Tao, Hiroaki

Total photoyield emission spectroscopy (TPYS) was applied to study the evolution of sub-gap states in hydrogen-treated amorphous In-Ga-Zn-O (a-IGZO) thin films. The a-IGZO thin films were subjected to hydrogen radicals and subsequently annealed in ultra-high vacuum (UHV) conditions. A clear onset of the electron emission was observed at around 4.3 eV from the hydrogen-treated a-IGZO thin films. After successive UHV annealing at 300 °C, the onset in the TPYS spectra was shifted to 4.15 eV, and the photoelectron emission from the sub-gap states was decreased as the annealing temperature was increased. In conjunction with the results of thermal desorption spectrometer, it was deducedmore » that the hydrogen atoms incorporated in the a-IGZO thin films induced metastable sub-gap states at around 4.3 eV from vacuum level just after the hydrogenation. It was also suggested that the defect configuration was changed due to the higher temperature UHV annealing, and that the hydrogen atoms desorbed with the involvement of Zn atoms. These experiments produced direct evidence to show the formation of sub-gap states as a result of hydrogen incorporation into the a-IGZO thin films.« less

Characterization of a Compact Cryogenic Package Approach to Ion Trap Quantum Comuting

NASA Astrophysics Data System (ADS)

Spivey, Robert; Vrijsen, Geert; Ahn, Byeong-Hyeon; Hudek, Kai; Crain, Stephen; van Rynbach, Andre; Rachel, Noek; Kim, Jungsang

One challenge for the expansion of trapped ion systems to a large scale is the lack of repeatable integration technology to realize compact and stable operating environment. In this work, we present a novel ion trapping environment where conventional ultra-high vacuum (UHV) chambers are replaced with a sealed ceramic package operating in a cryogenic environment. A microfabricated surface ion trap mounted on a 100-pin ceramic pin grid array (CPGA) package is placed in a UHV environment. A titanium lid with windows for optical access is then attached to the CPGA via an indium seal which maintains the UHV conditions for the ion trap. The trap package assembly is operated at cryogenic temperatures (5K) in order to freeze out most of the residual background gas. Activated charcoal is used to pump remaining helium and hydrogen molecules. Metallic Yb ablated using a Q-switched Nd:YAG laser at 1,064 nm is used as the atomic source. A compact radio frequency resonant circuit is used to create the RF potential for trapping. A low output impedance amplifier drives a superconducting inductor of value 2 uH in series with the trap capacitance in order to produce 200V at 26 MHz with low heating at 5K. We present the experimental progress towards trapping ions in this compact cryogenic setup.

Joint source-channel coding for motion-compensated DCT-based SNR scalable video.

PubMed

Kondi, Lisimachos P; Ishtiaq, Faisal; Katsaggelos, Aggelos K

2002-01-01

In this paper, we develop an approach toward joint source-channel coding for motion-compensated DCT-based scalable video coding and transmission. A framework for the optimal selection of the source and channel coding rates over all scalable layers is presented such that the overall distortion is minimized. The algorithm utilizes universal rate distortion characteristics which are obtained experimentally and show the sensitivity of the source encoder and decoder to channel errors. The proposed algorithm allocates the available bit rate between scalable layers and, within each layer, between source and channel coding. We present the results of this rate allocation algorithm for video transmission over a wireless channel using the H.263 Version 2 signal-to-noise ratio (SNR) scalable codec for source coding and rate-compatible punctured convolutional (RCPC) codes for channel coding. We discuss the performance of the algorithm with respect to the channel conditions, coding methodologies, layer rates, and number of layers.

The effect of layer-by-layer chitosan-hyaluronic acid coating on graft-to-bone healing of a poly(ethylene terephthalate) artificial ligament.

PubMed

Li, Hong; Ge, Yunsheng; Zhang, Pengyun; Wu, Lingxiang; Chen, Shiyi

2012-01-01

Surface coating with an organic layer-by-layer self-assembled template of chitosan and hyaluronic acid on a poly(ethylene terephthalate) (PET) artificial ligament was designed for the promotion and enhancement of graft-to-bone healing after artificial ligament implantation in a bone tunnel. The results of in vitro culturing of MC3T3-E1 mouse osteoblastic cells supported the hypothesis that the layer-by-layer coating of chitosan and hyaluronic acid could promote the cell compatibility of grafts and could promote osteoblast proliferation. A rabbit extra-articular tendon-to-bone healing model was used to evaluate the effect of this kind of surface-modified stainless artificial ligament in vivo. The final results proved that this organic compound coating could significantly promote and enhance new bone formation at the graft-bone interface histologically and, correspondingly, the experimental group with coating had significantly higher biomechanical properties compared with controls at 8 weeks (P < 0.05).

Signal acquisition and analysis for cortical control of neuroprosthetics.

PubMed

Tillery, Stephen I Helms; Taylor, Dawn M

2004-12-01

Work in cortically controlled neuroprosthetic systems has concentrated on decoding natural behaviors from neural activity, with the idea that if the behavior could be fully decoded it could be duplicated using an artificial system. Initial estimates from this approach suggested that a high-fidelity signal comprised of many hundreds of neurons would be required to control a neuroprosthetic system successfully. However, recent studies are showing hints that these systems can be controlled effectively using only a few tens of neurons. Attempting to decode the pre-existing relationship between neural activity and natural behavior is not nearly as important as choosing a decoding scheme that can be more readily deployed and trained to generate the desired actions of the artificial system. These artificial systems need not resemble or behave similarly to any natural biological system. Effective matching of discrete and continuous neural command signals to appropriately configured device functions will enable effective control of both natural and abstract artificial systems using compatible thought processes.

A simple method to produce 2D and 3D microfluidic paper-based analytical devices for clinical analysis.

PubMed

de Oliveira, Ricardo A G; Camargo, Fiamma; Pesquero, Naira C; Faria, Ronaldo Censi

2017-03-08

This paper describes the fabrication of 2D and 3D microfluidic paper-based analytical devices (μPADs) for monitoring glucose, total protein, and nitrite in blood serum and artificial urine. A new method of cutting and sealing filter paper to construct μPADs was demonstrated. Using an inexpensive home cutter printer soft cellulose-based filter paper was easily and precisely cut to produce pattern hydrophilic microchannels. 2D and 3D μPADs were designed with three detection zones each for the colorimetric detection of the analytes. A small volume of samples was added to the μPADs, which was photographed after 15 min using a digital camera. Both μPADs presented an excellent analytical performance for all analytes. The 2D device was applied in artificial urine samples and reached limits of detection (LODs) of 0.54 mM, 5.19 μM, and 2.34 μM for glucose, protein, and nitrite, respectively. The corresponding LODs of the 3D device applied for detecting the same analytes in artificial blood serum were 0.44 mM, 1.26 μM, and 4.35 μM. Copyright © 2017 Elsevier B.V. All rights reserved.

VHF Air/Ground Communications for Air Traffic Control: A Decision Tree Approach to System Innovations. Volume 2

DTIC Science & Technology

1993-07-01

GROUND RADIO ISSUES Multiple transmitters and receivers at a common site has been a dfficult integration issue for many communicaton systems...lower data rate vocoders become available. 10. Compatibility of modulation with channel availability and message integrity improvements, including...overrides can use in- frequency and path diversity, integrity improvements band signaling, busy channel overrides, and Frequency diversity and ARQ ARQ is

Mo doped DLC nanocomposite coatings with improved mechanical and blood compatibility properties

NASA Astrophysics Data System (ADS)

Tang, X. S.; Wang, H. J.; Feng, L.; Shao, L. X.; Zou, C. W.

2014-08-01

Mo (molybdenum) doped diamond like carbon (Mo-DLC) coatings with improved mechanical and blood compatibility properties were deposited by closed field unbalanced magnetron sputtering. The undoped and Mo-doped DLC coatings were analyzed by various characterization techniques such as Raman spectra, Atomic force microscopy, and temperature-dependent frictional wear testing. The results showed that the Mo-DLC coating with low Mo concentration was a effective protective coating with reduced residual stress and increased cohesive strength, and kept good wear resistance at the ambient temperature of 500 °C. The blood compatibility of Mo-DLC coatings was investigated by platelet adhesion. The results showed that the amount of thrombus on the Mo-DLC nanocomposite coatings was much less than that of thrombus on pyrolytic carbon films. The Mo-DLC nanocomposite coatings would be a new kind of promising materials applied to artificial heart valve and endovascula stent.

Does Consuming Sugar and Artificial Sweeteners Change Taste Preferences?

PubMed

Bartolotto, Carole

2015-01-01

Americans consume 22.3 teaspoons of added caloric sweeteners a day. Sweeteners range from 180 to 13,000 times sweeter than sugar. In summer 2014, 20 people from Kaiser Permanente California facilities cut out all added sugars and artificial sweeteners for 2 weeks: 95% of participants found that sweet foods and drinks tasted sweeter or too sweet, 75% found that other foods tasted sweeter, and 95% said moving forward they would use less or even no sugar. Additionally, 86.6% of participants stopped craving sugar after 6 days.

Genetic algorithm applied to the selection of factors in principal component-artificial neural networks: application to QSAR study of calcium channel antagonist activity of 1,4-dihydropyridines (nifedipine analogous).

PubMed

Hemmateenejad, Bahram; Akhond, Morteza; Miri, Ramin; Shamsipur, Mojtaba

2003-01-01

A QSAR algorithm, principal component-genetic algorithm-artificial neural network (PC-GA-ANN), has been applied to a set of newly synthesized calcium channel blockers, which are of special interest because of their role in cardiac diseases. A data set of 124 1,4-dihydropyridines bearing different ester substituents at the C-3 and C-5 positions of the dihydropyridine ring and nitroimidazolyl, phenylimidazolyl, and methylsulfonylimidazolyl groups at the C-4 position with known Ca(2+) channel binding affinities was employed in this study. Ten different sets of descriptors (837 descriptors) were calculated for each molecule. The principal component analysis was used to compress the descriptor groups into principal components. The most significant descriptors of each set were selected and used as input for the ANN. The genetic algorithm (GA) was used for the selection of the best set of extracted principal components. A feed forward artificial neural network with a back-propagation of error algorithm was used to process the nonlinear relationship between the selected principal components and biological activity of the dihydropyridines. A comparison between PC-GA-ANN and routine PC-ANN shows that the first model yields better prediction ability.

Biocorrosion Evaluation on a Zr-Cu-Ag-Ti Metallic Glass

NASA Astrophysics Data System (ADS)

Kumar, Shresh; Anwar, Rebin; Ryu, Wookha; Park, E. S.; Vincent, S.

2018-04-01

Metallic glasses are in high demand for fabrication of variety of innovative products, in particular surgical and biomedical tools and devices owing to its excellent biocompatible properties. In the present investigation, a novel Zr39.5Cu50.5Ag4Ti6 metallic glass composition was synthesized using melt spinning technique. Potentiodynamic polarization studies were conducted to investigate bio-corrosion behaviour of Zr39.5Cu50.5Ag4Ti6 metallic glass. The test were conducted in various simulated artificial body conditions such as artificial saliva solution, phosphate-buffered saline solution, artificial blood plasma solution, and Hank’s balanced saline solution. The bio-corrosion results of metallic glass were compared with traditional biomaterials. The study aims to provide bio-compatible properties of Zr39.5Cu50.5Ag4Ti6 metallic glass.

33 CFR 162.132 - Connecting waters from Lake Huron to Lake Erie; communications rules.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (2) Channel 12 (156.60 mhz) between Lake St. Clair Light and Detroit River Light. (b) Radiotelephone... Cut Light “7” Lake Huron Cut Lighted Buoy “1” Report. Report St. Clair/Black River Junction Light Report. Stag Island Upper Light Report. Report Marine City Salt Dock Light Report. Report Grande Pointe...

Insects at low pressure: applications to artificial ecosystems and implications for global windborne distribution

NASA Technical Reports Server (NTRS)

Cockell, C.; Catling, D.; Waites, H.

1999-01-01

Insects have a number of potential roles in closed-loop life support systems. In this study we examined the tolerance of a range of insect orders and life stages to drops in atmospheric pressure using a terrestrial atmosphere. We found that all insects studied could tolerate pressures down to 100 mb. No effects on insect respiration were noted down to 500 mb. Pressure toleration was not dependent on body volume. Our studies demonstrate that insects are compatible with plants in low-pressure artificial and closed-loop ecosystems. The results also have implications for arthropod colonization and global distribution on Earth.

Surface development of a brazing alloy during heat treatment-a comparison between UHV and APXPS

NASA Astrophysics Data System (ADS)

Rullik, L.; Johansson, N.; Bertram, F.; Evertsson, J.; Stenqvist, T.; Lundgren, E.

2018-01-01

In an attempt to bridge the pressure gap, APXPS was used to follow the surface development of an aluminum brazing sheet during heating in an ambient oxygen-pressure mimicking the environment of an industrial brazing furnace. The studied aluminum alloy brazing sheet is a composite material consisting of two aluminum alloy standards whose surface is covered with a native aluminum oxide film. To emphasize the necessity of studies of this system in ambient sample environments it is compared to measurements in UHV. Changes in thickness and composition of the surface oxide were followed after heating to 300 °C, 400 °C, and 500 °C. The two sets presented in this paper show that the surface development strongly depends on the environment the sample is heated in.

Study of Residual Gas Analyser (RGA) Response towards Known Leaks

NASA Astrophysics Data System (ADS)

Pathan, Firozkhan S.; Khan, Ziauddin; Semwal, Pratibha; George, Siju; Raval, Dilip C.; Thankey, Prashant L.; Manthena, Himabindu; Yuvakiran, Paravastu; Dhanani, Kalpesh R.

2012-11-01

Helium leak testing is the most versatile form of weld qualification test for any vacuum application. Almost every ultra-high vacuum (UHV) system utilizes this technique for insuring leak tightness for the weld joints as well as demountable joints. During UHV system under operational condition with many other integrated components, in-situ developed leaks identification becomes one of the prime aspect for maintaining the health of such system and for continuing the experiments onwards. Since online utilization of leak detector (LD) has many practical limitations, residual gas analyser (RGA) can be used as a potential instrument for online leak detection. For this purpose, a co-relation for a given leak rate between Leak Detector and RGA is experimentally established. This paper describes the experimental aspect and the relationship between leak detector and RGA.

An ultrahigh vacuum multipurpose specimen chamber with sample introduction system for in situ transmission electron microscopy investigations

NASA Technical Reports Server (NTRS)

Heinemann, K.; Poppa, H.

1986-01-01

A commercial transmission electron microscope (TEM), with flat-plate upper pole piece configuration of the objective lens, and top-entry specimen introduction was modified by introducing an ultrahigh vacuum (UHV) specimen chamber for in situ TEM experimentation. The pumping and design principles and special features of this UHV chamber, which makes it possible to obtain 5 x 10 to the -10th mbar pressure at the site of the specimen, while maintaining the airlock system that allows operation in the 10 to the -10th mbar range within 15 min after specimen change, are described. Design operating pressures and image quality (resolution of metal particles smaller than 1 nm in size) were achieved. Schematic drawings and design dimensions are included.

Surface spectroscopy studies of the oxidation behavior of uranium

NASA Astrophysics Data System (ADS)

Bloch, J.; Atzmony, U.; Dariel, M. P.; Mintz, M. H.; Shamir, N.

1982-02-01

Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) techniques were utilized to study the oxidation behavior of clean uranium surfaces, at very low pressures of various atmospheres (UHV, H 2, O 2, and CO 2), at room temperature. Both for O 2 and CO 2, a precursor chemisorbed oxygen species has been identified at the very initial stage of the oxidation reaction. This chemisorbed oxygen transforms to the oxide form at a rate which depends on the pressure of the oxidizing atmosphere. Residual gaseous carbon compounds which are present even under UHV conditions result in the simultaneous formation of surface carbide which accompanies the initial stage of oxidation. This carbide however decomposes later as oxidation proceeds. Adventitious hydrocarbon adsorption occurs on the formed oxide layer.

Influence of the surface chemistry on TiO2 - TiO2 nanocontact forces as measured by an UHV-AFM

NASA Astrophysics Data System (ADS)

Kunze, Christian; Giner, Ignacio; Torun, Boray; Grundmeier, Guido

2014-03-01

Particle-wall contact forces between a TiO2 film coated AFM tip and TiO2(1 1 0) single crystal surfaces were analyzed by means of UHV-AFM. As a reference system an octadecylphosphonic acid monolayer covered TiO2(1 1 0) surface was studied. The defect chemistry of the TiO2 substrate was modified by Ar ion bombardment, water dosing at 3 × 10-6 Pa and an annealing step at 473 K which resulted in a varying density of Ti(III) states. The observed contact forces are correlated to the surface defect density and are discussed in terms of the change in the electronic structure and its influence on the Hamaker constant.

MIMIC-compatible GaAs and InP field effect controlled transferred electron (FECTED) oscillators

NASA Astrophysics Data System (ADS)

Scheiber, Helmut; Luebke, Kurt; Diskus, Christian G.; Thim, Hartwig W.; Gruetzmacher, D.

1989-12-01

A MIMIC-(millimeter and microwave integrated circuit) compatible transferred electron oscillator is investigated which utilizes the frequency-independent negative resistance of the stationary charge dipole domain that forms in the channel of a MESFET. The device structure, analysis, and simulation are described. Devices fabricated from GaAs and InP exhibit very high power levels of 56 mW at 29 GHz and 55 mW at 34 GHz, respectively. Continuous wave power levels are somewhat lower (30 mW).

A new artificial diet for western corn rootworm larvae is compatible with and detects resistance to all current Bt toxins

USDA-ARS?s Scientific Manuscript database

Insect resistance to transgenic crops expressing one or more genes from Bacillus thuringiensis Berliner (Bt) is a growing concern for farmers, regulatory agencies, the seed industry, and researchers alike. Western corn rootworm (Diabrotica virgifera virgifera LeConte) is a pest of corn (Zea mays L.)...

Respiratory pattern changes during costovertebral joint movement.

PubMed

Shannon, R

1980-05-01

Experiments were conducted to determine if costovertebral joint manipulation (CVJM) could influence the respiratory pattern. Phrenic efferent activity (PA) was monitored in dogs that were anesthetized with Dial-urethane, vagotomized, paralyzed, and artificially ventilated. Ribs 6-10 (bilaterally) were cut and separated from ribs 5-11. Branches of thoracic nerves 5-11 were cut, leaving only the joint nerve supply intact. Manual joint movement in an inspiratory or expiratory direction had an inhibitory effect on PA. Sustained displacement of the ribs could inhibit PA for a duration equal to numerous respiratory cycles. CVJM in synchrony with PA resulted in an increased respiratory rate. The inspiratory inhibitory effect of joint receptor stimulation was elicited with manual chest compression in vagotomized spontaneously breathing dogs, but not with artificial lung inflation or deflation. It is concluded that the effect of CVJM on the respiratory pattern is due to stimulation of joint mechanoreceptors, and that they exert their influence in part via the medullary-pontine rhythm generator.

Oligosaccharide composition of the neurotoxin responsive Na/sup +/ channel and the requirement of sialic acid for activity

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

Negishi, M.; Shaw, G.W.; Glick, M.C.

1986-05-01

The neurotoxin responsive Na/sup +/ channel was purified to homogeneity in an 18% yield from a clonal cell line of mouse neuroblastoma, N-18, metabolically labeled with L-(/sup 3/H)fucose. The Na/sup +/ channel, a glycoprotein, M/sub r/=200,000 (gradient 7-14% PAGE) was digested with Pronase and the glycopeptides were characterized by serial lectin affinity chromatography. greater than 90% of the oligosaccharides contained sialic acid and 18% were biantennary, 39% were triantennary and 30% tetraantennary. The glycoprotein was reconstituted into artificial phospholipid vesicles and /sup 86/Rb flux was stimulated (65%) by 200 ..mu..M veratridine and 1.2 ..mu..g of scorpion venom and was inhibitedmore » (95%) by 5 ..mu..M tetrodotoxin. The requirement of sialic acid for Na/sup +/ channel activity was demonstrated since neuraminidase (0.01 U) treatment of the reconstituted glycoprotein eliminated the response of /sup 86/Rb flux to the stimulating neurotoxins. In other experiments, treatment of N-18 cells with 10 ..mu..M swainsonine, an inhibitor of glycoprotein processing, altered the oligosaccharide composition of the Na/sup +/ channel. When the abnormally glycosylated Na/sup +/ channel was reconstituted into artificial phospholipid vesicles, /sup 86/Rb flux in response to neurotoxins was impaired. Thus, glycosylation of the polypeptide with oligosaccharides of specific composition and structure is essential for expression of the biological activity of the neurotoxin responsive Na/sup +/ channel.« less

ROMI-RIP: Rough Mill RIP-first simulator user's guide

Treesearch

R. Edward Thomas

1995-01-01

The ROugh Mill RIP-first simulator (ROMI-RIP) is a computer software package for IBM compatible personal computers that simulates current industrial practices for gang-ripping lumber. This guide shows the user how to set and examine the results of simulations regarding current or proposed mill practices. ROMI-RIP accepts cutting bills with up to 300 different part...

Method for laser welding ultra-thin metal foils

DOEpatents

Pernicka, J.C.; Benson, D.K.; Tracy, C.E.

1996-03-26

A method for simultaneously cutting and welding ultra-thin foils having a thickness of less than 0.002 inches wherein two ultra-thin films are stacked and clamped together. A pulsed laser such as of the Neodymium: YAG type is provided and the beam of the laser is directed onto the stacked films to cut a channel through the films. The laser is moved relative to the stacked foils to cut the stacked foils at successive locations and to form a plurality of connected weld beads to form a continuous weld. 5 figs.

Method for laser welding ultra-thin metal foils

DOEpatents

Pernicka, John C.; Benson, David K.; Tracy, C. Edwin

1996-01-01

A method for simultaneously cutting and welding ultra-thin foils having a thickness of less than 0.002 inches wherein two ultra-thin films are stacked and clamped together. A pulsed laser such as of the Neodymium: YAG type is provided and the beam of the laser is directed onto the stacked films to cut a channel through the films. The laser is moved relative to the stacked foils to cut the stacked foils at successive locations and to form a plurality of connected weld beads to form a continuous weld.

Soft Sensing of Non-Newtonian Fluid Flow in Open Venturi Channel Using an Array of Ultrasonic Level Sensors—AI Models and Their Validations

PubMed Central

Viumdal, Håkon; Mylvaganam, Saba

2017-01-01

In oil and gas and geothermal installations, open channels followed by sieves for removal of drill cuttings, are used to monitor the quality and quantity of the drilling fluids. Drilling fluid flow rate is difficult to measure due to the varying flow conditions (e.g., wavy, turbulent and irregular) and the presence of drilling cuttings and gas bubbles. Inclusion of a Venturi section in the open channel and an array of ultrasonic level sensors above it at locations in the vicinity of and above the Venturi constriction gives the varying levels of the drilling fluid in the channel. The time series of the levels from this array of ultrasonic level sensors are used to estimate the drilling fluid flow rate, which is compared with Coriolis meter measurements. Fuzzy logic, neural networks and support vector regression algorithms applied to the data from temporal and spatial ultrasonic level measurements of the drilling fluid in the open channel give estimates of its flow rate with sufficient reliability, repeatability and uncertainty, providing a novel soft sensing of an important process variable. Simulations, cross-validations and experimental results show that feedforward neural networks with the Bayesian regularization learning algorithm provide the best flow rate estimates. Finally, the benefits of using this soft sensing technique combined with Venturi constriction in open channels are discussed. PMID:29072595

Transportation behavior of alkali ions through a cell membrane ion channel. A quantum chemical description of a simplified isolated model.

PubMed

Billes, Ferenc; Mohammed-Ziegler, Ildikó; Mikosch, Hans

2012-08-01

Quantum chemical model calculations were carried out for modeling the ion transport through an isolated ion channel of a cell membrane. An isolated part of a natural ion channel was modeled. The model channel was a calixarene derivative, hydrated sodium and potassium ions were the models of the transported ion. The electrostatic potential of the channel and the energy of the channel-ion system were calculated as a function of the alkali ion position. Both attractive and repulsive ion-channel interactions were found. The calculations - namely the dependence of the system energy and the atomic charges of the water molecules with respect to the position of the alkali ion in the channel - revealed the molecular-structural background of the potassium selectivity of this artificial ion channel. It was concluded that the studied ion channel mimics real biological ion channel quite well.

Artificial neural network modeling of a deflector in a grooved channel as well as optimization of its effective parameters

NASA Astrophysics Data System (ADS)

Abdollahi, Azita; Shams, Mehrzad; Abdollahi, Anita

2018-01-01

One of methods available to increase the rate of heat transfer in channels with parallel plates is making grooves in them. But, the fundamental problem of this method is the formation of stagnation zone in the grooves and as a result formation a zone with low energy transfer. In this paper, the effect of placing curved deflectors (geometries with elliptical forms) in channel on thermal and hydraulic characteristic of the fluid flow- with the aim of directing of the flow into the grooves and as a result increasing the rate of heat transfer in this zone- are investigated and heat transfer coefficient and pressure drop are calculated for different values of Reynolds number and geometrical parameters of the deflector (its small and large radiuses). The results show that the presence of the deflector in the channel significantly increases the heat transfer rate compare to the channel without deflector. Of course, it should be noted that this work also increases the pressure drop. So, finally in order to determine configurations of the deflector causing minimum pressure drop, maximum Nusselt number or a balance between them, optimization algorithm consisting of artificial neural network and multi-objective genetic algorithm was utilized to calculate the optimal values of these parameters.

On-line two-dimensional capillary electrophoresis with mass spectrometric detection using a fully electric isolated mechanical valve.

PubMed

Kohl, Felix J; Montealegre, Cristina; Neusüß, Christian

2016-04-01

CE is becoming more and more important in many fields of bioanalytical chemistry. Besides optical detection, hyphenation to ESI-MS detection is increasingly applied for sensitive identification purposes. Unfortunately, many CE techniques and methods established in research and industry are not compatible to ESI-MS since essential components of the background electrolyte interfere in ES ionization. In order to identify unknown peaks in established CE methods, here, a heart-cut 2D-CE separation system is introduced using a fully isolated mechanical valve with an internal loop of only 20 nL. In this system, the sample is separated using potentially any non-ESI compatible method in the first separation dimension. Subsequently, the portion of interest is cut by the internal sample loop of the valve and reintroduced to the second dimension where the interfering compounds are removed, followed by ESI-MS detection. When comparing the separation efficiency of the system with the valve to a system using a continuous capillary only a slight increase in peak width is observed. Ultraviolet/visible detection is integrated in the first dimension for switching time determination, enabling reproducible cutting of peaks of interest. The feasibility of the system is successfully demonstrated by a 2D analysis of a BSA tryptic digest sample using a nonvolatile (phosphate based) background electrolyte in the first dimension. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

33 CFR 165.703 - Tampa Bay, Florida-Safety Zone.

Code of Federal Regulations, 2013 CFR

2013-07-01

... loaded anhydrous ammonia vessel and the width of the channel in the following areas: (1) For inbound tank vessels loaded with anhydrous ammonia, Tampa Bay Cut “F” Channel from Lighted Buoys “3F” and “4F” north... anhydrous ammonia receiving terminals to Port Sutton the safety zone includes, in addition to the area in...

33 CFR 165.703 - Tampa Bay, Florida-Safety Zone.

Code of Federal Regulations, 2014 CFR

2014-07-01

... loaded anhydrous ammonia vessel and the width of the channel in the following areas: (1) For inbound tank vessels loaded with anhydrous ammonia, Tampa Bay Cut “F” Channel from Lighted Buoys “3F” and “4F” north... anhydrous ammonia receiving terminals to Port Sutton the safety zone includes, in addition to the area in...

33 CFR 165.703 - Tampa Bay, Florida-Safety Zone.

Code of Federal Regulations, 2011 CFR

2011-07-01

... loaded anhydrous ammonia vessel and the width of the channel in the following areas: (1) For inbound tank vessels loaded with anhydrous ammonia, Tampa Bay Cut “F” Channel from Lighted Buoys “3F” and “4F” north... anhydrous ammonia receiving terminals to Port Sutton the safety zone includes, in addition to the area in...

33 CFR 165.703 - Tampa Bay, Florida-Safety Zone.

Code of Federal Regulations, 2012 CFR

2012-07-01

... loaded anhydrous ammonia vessel and the width of the channel in the following areas: (1) For inbound tank vessels loaded with anhydrous ammonia, Tampa Bay Cut “F” Channel from Lighted Buoys “3F” and “4F” north... anhydrous ammonia receiving terminals to Port Sutton the safety zone includes, in addition to the area in...

33 CFR 165.703 - Tampa Bay, Florida-Safety Zone.

Code of Federal Regulations, 2010 CFR

2010-07-01

... loaded anhydrous ammonia vessel and the width of the channel in the following areas: (1) For inbound tank vessels loaded with anhydrous ammonia, Tampa Bay Cut “F” Channel from Lighted Buoys “3F” and “4F” north... anhydrous ammonia receiving terminals to Port Sutton the safety zone includes, in addition to the area in...

Monolithically compatible impedance measurement

DOEpatents

Ericson, Milton Nance; Holcomb, David Eugene

2002-01-01

A monolithic sensor includes a reference channel and at least one sensing channel. Each sensing channel has an oscillator and a counter driven by the oscillator. The reference channel and the at least one sensing channel being formed integrally with a substrate and intimately nested with one another on the substrate. Thus, the oscillator and the counter have matched component values and temperature coefficients. A frequency determining component of the sensing oscillator is formed integrally with the substrate and has an impedance parameter which varies with an environmental parameter to be measured by the sensor. A gating control is responsive to an output signal generated by the reference channel, for terminating counting in the at least one sensing channel at an output count, whereby the output count is indicative of the environmental parameter, and successive ones of the output counts are indicative of changes in the environmental parameter.

Automated Cell-Cutting for Cell Cloning

NASA Astrophysics Data System (ADS)

Ichikawa, Akihiko; Tanikawa, Tamio; Matsukawa, Kazutsugu; Takahashi, Seiya; Ohba, Kohtaro

We develop an automated cell-cutting technique for cell cloning. Animal cells softened by the cytochalasin treatment are injected into a microfluidic chip. The microfluidic chip contains two orthogonal channels: one microchannel is wide, used to transport cells, and generates the cutting flow; the other is thin and used for aspiration, fixing, and stretching of the cell. The injected cell is aspirated and stretched in the thin microchannel. Simultaneously, the volumes of the cell before and after aspiration are calculated; the volumes are used to calculate the fluid flow required to aspirate half the volume of the cell into the thin microchannel. Finally, we apply a high-speed flow in the orthogonal microchannel to bisect the cell. This paper reports the cutting process, the cutting system, and the results of the experiment.

Comparing two quantitative methods for studying remineralization of artificial caries.

PubMed

Lo, E C M; Zhi, Q H; Itthagarun, A

2010-04-01

To compare the detection of changes before and after remineralization of artificial enamel and dentin caries by microCT scanning, polarized light microscopy (PLM) and transverse microradiography (TMR). Fourteen extracted premolars were cut into tooth blocks and painted with an acid-resistant varnish leaving one enamel and one dentin surface exposed. The tooth blocks were immersed into demineralizing solution for 4 days to produce artificial caries-like lesions and scanned by microCT. Then the 14 tooth blocks were randomly allocated into two groups. Seven tooth blocks in Group I were cut longitudinally through the exposed surface into 100-150 microm thick sections and microradiographs were taken. The other seven tooth blocks in Group II were left intact. All the tooth blocks and sections were then immersed into remineralizing solution for 5 days. PLM and TMR of the tooth sections in Group I were taken again. Depth of the lesion on the TMR was measured. Tooth blocks in Group II were scanned by microCT. Mean lesion depth in Group I reduced by 13.0% and 8.2% after remineralization for enamel and dentin, respectively (paired t-test, P<0.001). In Group II, linear attenuation coefficient (LAC) of the region of interest (ROI) increased by 11.1% and 23.8% after remineralization for enamel and dentin lesions, respectively (paired t-test, P<0.001). Both microCT and microradiography are able to detect a change of similar magnitude in the artificial caries lesions after remineralization. MicroCT may be used to substitute TMR and PLM in in vitro studies about caries. Copyright 2010 Elsevier Ltd. All rights reserved.

Encoding and Decoding of Multi-Channel ICMS in Macaque Somatosensory Cortex.

PubMed

Dadarlat, Maria C; Sabes, Philip N

2016-01-01

Naturalistic control of brain-machine interfaces will require artificial proprioception, potentially delivered via intracortical microstimulation (ICMS). We have previously shown that multi-channel ICMS can guide a monkey reaching to unseen targets in a planar workspace. Here, we expand on that work, asking how ICMS is decoded into target angle and distance by analyzing the performance of a monkey when ICMS feedback was degraded. From the resulting pattern of errors, we found that the animal's estimate of target direction was consistent with a weighted circular-mean strategy-close to the optimal decoding strategy given the ICMS encoding. These results support our previous finding that animals can learn to use this artificial sensory feedback in an efficient and naturalistic manner.

Polycrystalline silicon thin-film transistors with location-controlled crystal grains fabricated by excimer laser crystallization

NASA Astrophysics Data System (ADS)

Tsai, Chun-Chien; Lee, Yao-Jen; Chiang, Ko-Yu; Wang, Jyh-Liang; Lee, I.-Che; Chen, Hsu-Hsin; Wei, Kai-Fang; Chang, Ting-Kuo; Chen, Bo-Ting; Cheng, Huang-Chung

2007-11-01

In this paper, location-controlled silicon crystal grains are fabricated by the excimer laser crystallization method which employs amorphous silicon spacer structure and prepatterned thin films. The amorphous silicon spacer in nanometer-sized width formed using spacer technology is served as seed crystal to artificially control superlateral growth phenomenon during excimer laser irradiation. An array of 1.8-μm-sized disklike silicon grains is formed, and the n-channel thin-film transistors whose channels located inside the artificially-controlled crystal grains exhibit higher performance of field-effect-mobility reaching 308cm2/Vs as compared with the conventional ones. This position-manipulated silicon grains are essential to high-performance and good uniformity devices.

Resonant slepton production yields CMS e e j j and e p Tj j excesses

NASA Astrophysics Data System (ADS)

Allanach, Ben; Biswas, Sanjoy; Mondal, Subhadeep; Mitra, Manimala

2015-01-01

Recent CMS searches for dileptoquark production report local excesses of 2.4 σ in an e e j j channel and 2.6 σ in an e p Tj j channel. Here, we simultaneously explain both excesses with resonant slepton production in R -parity violating supersymmetry. We consider resonant slepton production, which decays to a lepton and a chargino/neutralino, followed by three-body decays of the neutralino/chargino via an R -parity violating coupling. There are regions of parameter space which are also compatible at the 95% confidence level with a 2.8 σ e e j j excess in a recent CMS WR search, while being compatible with other direct search constraints. Phase II of the GERDA neutrinoless double beta decay (0 ν β β ) experiment will probe a sizable portion of the good-fit region.

A clinic compatible, open source electrophysiology system.

PubMed

Hermiz, John; Rogers, Nick; Kaestner, Erik; Ganji, Mehran; Cleary, Dan; Snider, Joseph; Barba, David; Dayeh, Shadi; Halgren, Eric; Gilja, Vikash

2016-08-01

Open source electrophysiology (ephys) recording systems have several advantages over commercial systems such as customization and affordability enabling more researchers to conduct ephys experiments. Notable open source ephys systems include Open-Ephys, NeuroRighter and more recently Willow, all of which have high channel count (64+), scalability, and advanced software to develop on top of. However, little work has been done to build an open source ephys system that is clinic compatible, particularly in the operating room where acute human electrocorticography (ECoG) research is performed. We developed an affordable (<; $10,000) and open system for research purposes that features power isolation for patient safety, compact and water resistant enclosures and 256 recording channels sampled up to 20ksam/sec, 16-bit. The system was validated by recording ECoG with a high density, thin film device for an acute, awake craniotomy study at UC San Diego, Thornton Hospital Operating Room.

A multipurpose ultra-high vacuum-compatible chamber for in situ X-ray surface scattering studies over a wide range of temperature and pressure environment conditions

NASA Astrophysics Data System (ADS)

Ferrer, P.; Rubio-Zuazo, J.; Heyman, C.; Esteban-Betegón, F.; Castro, G. R.

2013-03-01

A low/high temperature (60-1000K) and pressure (10-10-3x103 mbar) "baby chamber", specially adapted to the grazing-incidence X-ray scattering station, has been designed, developed and installed at the Spanish CRG BM25 SpLine beamline at European Synchrotron Radiation Facility. The chamber has a cylindrical form with 100 mm of diameter, built on a 360° beryllium nipple of 150 mm height. The UHV equipment and a turbo pump are located on the upper part of the chamber to leave a wide solid angle for exploring reciprocal space. The chamber features 4 CF16 and 5 CF40 ports for electrical feed through and leak valves, ion gun, etc. The heat exchanger is a customized compact LN2 (or LHe) continuous flow cryostat. The sample is mounted on a Mo support on the heat exchanger, which has in the back side a BORALECTRIC® Heater Elements. Experiments of surfaces/interfaces/ multilayer materials, thin films or single crystals in a huge variety of environments can be performed, also in situ studies of growth or evolution of the samples. Data measurement can be collected with a punctual and a bi-dimensional detector, being possible to simultaneously use them.

Trapping ultracold gases near cryogenic materials with rapid reconfigurability

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

Naides, Matthew A.; Turner, Richard W.; Lai, Ruby A.

We demonstrate an atom chip trapping system that allows the placement and high-resolution imaging of ultracold atoms within microns from any ≲100 μm-thin, UHV-compatible material, while also allowing sample exchange with minimal experimental downtime. The sample is not connected to the atom chip, allowing rapid exchange without perturbing the atom chip or laser cooling apparatus. Exchange of the sample and retrapping of atoms has been performed within a week turnaround, limited only by chamber baking. Moreover, the decoupling of sample and atom chip provides the ability to independently tune the sample temperature and its position with respect to the trapped ultracoldmore » gas, which itself may remain in the focus of a high-resolution imaging system. As a first demonstration of this system, we have confined a 700-nK cloud of 8 × 10{sup 4} {sup 87}Rb atoms within 100 μm of a gold-mirrored 100-μm-thick silicon substrate. The substrate was cooled to 35 K without use of a heat shield, while the atom chip, 120 μm away, remained at room temperature. Atoms may be imaged and retrapped every 16 s, allowing rapid data collection.« less

Vacuum system of the compact Energy Recovery Linac

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

Honda, T., E-mail: tohru.honda@kek.jp; Tanimoto, Y.; Nogami, T.

2016-07-27

The compact Energy Recovery Linac (cERL), a test accelerator to establish important technologies demanded for future ERL-based light sources, was constructed in late 2013 at KEK. The accelerator was successfully commissioned in early 2014, and demonstrated beam circulation with energy recovery. In the cERL vacuum system, low-impedance vacuum components are required to circulate high-intensity, low-emittance and short-bunch electron beams. We therefore developed ultra-high-vacuum (UHV)-compatible flanges that can connect beam tubes seamlessly, and employed retractable beam monitors, namely, a movable Faraday cup and screen monitors. In most parts of the accelerator, pressures below 1×10{sup −7} Pa are required to mitigate beam-gasmore » interactions. Particularly, near the photocathode electron gun and the superconducting (SC) cavities, pressures below 1×10{sup −8} Pa are required. The beam tubes in the sections adjoining the SC cavities were coated with non-evaporable getter (NEG) materials, to reduce gas condensation on the cryo-surfaces. During the accelerator commissioning, stray magnetic fields from the permanent magnets of some cold cathode gauges (CCGs) were identified as a source of the disturbance to the beam orbit. Magnetic shielding was specially designed as a remedy for this issue.« less

In vivo feasibility test using transparent carbon nanotube-coated polydimethylsiloxane sheet at brain tissue and sciatic nerve.

PubMed

Wang, Caifeng; Oh, Sangjin; Lee, Hyun Ah; Kang, Jieun; Jeong, Ki-Jae; Kang, Seon Woo; Hwang, Dae Youn; Lee, Jaebeom

2017-06-01

Carbon nanotubes, with their unique and outstanding properties, such as strong mechanical strength and high electrical conductivity, have become very popular for the repair of tissues, particularly for those requiring electrical stimuli. Polydimethylsiloxane (PDMS)-based elastomers have been used in a wide range of biomedical applications because of their optical transparency, physiological inertness, blood compatibility, non-toxicity, and gas permeability. In present study, most of artificial nerve guidance conduits (ANGCs) are not transparent. It is hard to confirm the position of two stumps of damaged nerve during nerve surgery and the conduits must be cut open again to observe regenerative nerves after surgery. Thus, a novel preparation method was utilized to produce a transparent sheet using PDMS and multiwalled carbon nanotubes (MWNTs) via printing transfer method. Characterization of the PDMS/MWNT (PM) sheets revealed their unique physicochemical properties, such as superior mechanical strength, a certain degree of electrical conductivity, and high transparency. Characterization of the in vitro and in vivo usability was evaluated. PM sheets showed high biocompatibility and adhesive ability. In vivo feasibility tests of rat brain tissue and sciatic nerve revealed the high transparency of PM sheets, suggesting that it can be used in the further development of ANGCs. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1736-1745, 2017. © 2017 Wiley Periodicals, Inc.

Prioritized packet video transmission over time-varying wireless channel using proactive FEC

NASA Astrophysics Data System (ADS)

Kumwilaisak, Wuttipong; Kim, JongWon; Kuo, C.-C. Jay

2000-12-01

Quality of video transmitted over time-varying wireless channels relies heavily on the coordinated effort to cope with both channel and source variations dynamically. Given the priority of each source packet and the estimated channel condition, an adaptive protection scheme based on joint source-channel criteria is investigated via proactive forward error correction (FEC). With proactive FEC in Reed Solomon (RS)/Rate-compatible punctured convolutional (RCPC) codes, we study a practical algorithm to match the relative priority of source packets and instantaneous channel conditions. The channel condition is estimated to capture the long-term fading effect in terms of the averaged SNR over a preset window. Proactive protection is performed for each packet based on the joint source-channel criteria with special attention to the accuracy, time-scale match, and feedback delay of channel status estimation. The overall gain of the proposed protection mechanism is demonstrated in terms of the end-to-end wireless video performance.

Creating a Vision Channel for Observing Deep-Seated Anatomy in Medical Augmented Reality

NASA Astrophysics Data System (ADS)

Wimmer, Felix; Bichlmeier, Christoph; Heining, Sandro M.; Navab, Nassir

The intent of medical Augmented Reality (AR) is to augment the surgeon's real view on the patient with the patient's interior anatomy resulting from a suitable visualization of medical imaging data. This paper presents a fast and user-defined clipping technique for medical AR allowing for cutting away any parts of the virtual anatomy and images of the real part of the AR scene hindering the surgeon's view onto the deepseated region of interest. Modeled on cut-away techniques from scientific illustrations and computer graphics, the method creates a fixed vision channel to the inside of the patient. It enables a clear view on the focussed virtual anatomy and moreover improves the perception of spatial depth.

Tubular Unimolecular Transmembrane Channels: Construction Strategy and Transport Activities.

PubMed

Si, Wen; Xin, Pengyang; Li, Zhan-Ting; Hou, Jun-Li

2015-06-16

Lipid bilayer membranes separate living cells from their environment. Membrane proteins are responsible for the processing of ion and molecular inputs and exports, sensing stimuli and signals across the bilayers, which may operate in a channel or carrier mechanism. Inspired by these wide-ranging functions of membrane proteins, chemists have made great efforts in constructing synthetic mimics in order to understand the transport mechanisms, create materials for separation, and develop therapeutic agents. Since the report of an alkylated cyclodextrin for transporting Cu(2+) and Co(2+) by Tabushi and co-workers in 1982, chemists have constructed a variety of artificial transmembrane channels by making use of either the multimolecular self-assembly or unimolecular strategy. In the context of the design of unimolecular channels, important advances have been made, including, among others, the tethering of natural gramicidin A or alamethicin and the modification of various macrocycles such as crown ethers, cyclodextrins, calixarenes, and cucurbiturils. Many of these unimolecular channels exhibit high transport ability for metal ions, particularly K(+) and Na(+). Concerning the development of artificial channels based on macrocyclic frameworks, one straightforward and efficient approach is to introduce discrete chains to reinforce their capability to insert into bilayers. Currently, this approach has found the widest applications in the systems of crown ethers and calixarenes. We envisioned that for macrocycle-based unimolecular channels, control of the arrangement of the appended chains in the upward and/or downward direction would favor the insertion of the molecular systems into bilayers, while the introduction of additional interactions among the chains would further stabilize a tubular conformation. Both factors should be helpful for the formation of new efficient channels. In this Account, we discuss our efforts in designing new unimolecular artificial channels from tubular pillar[n]arenes by extending their lengths with various ester, hydrazide, and short peptide chains. We have utilized well-defined pillar[5]arene and pillar[6]arene as rigid frameworks that allow the appended chains to afford extended tubular structures. We demonstrate that the hydrazide and peptide chains form intramolecular N-H···O═C hydrogen bonds that enhance the tubular conformation of the whole molecule. The new pillar[n]arene derivatives have been successfully applied as unimolecular channels for the selective transport of protons, water, and amino acids and the voltage-gated transport of K(+). We also show that aromatic hydrazide helices and macrocycles appended with peptide chains are able to mediate the selective transport of NH4(+).

Development of haptic based piezoresistive artificial fingertip: Toward efficient tactile sensing systems for humanoids.

PubMed

TermehYousefi, Amin; Azhari, Saman; Khajeh, Amin; Hamidon, Mohd Nizar; Tanaka, Hirofumi

2017-08-01

Haptic sensors are essential devices that facilitate human-like sensing systems such as implantable medical devices and humanoid robots. The availability of conducting thin films with haptic properties could lead to the development of tactile sensing systems that stretch reversibly, sense pressure (not just touch), and integrate with collapsible. In this study, a nanocomposite based hemispherical artificial fingertip fabricated to enhance the tactile sensing systems of humanoid robots. To validate the hypothesis, proposed method was used in the robot-like finger system to classify the ripe and unripe tomato by recording the metabolic growth of the tomato as a function of resistivity change during a controlled indention force. Prior to fabrication, a finite element modeling (FEM) was investigated for tomato to obtain the stress distribution and failure point of tomato by applying different external loads. Then, the extracted computational analysis information was utilized to design and fabricate nanocomposite based artificial fingertip to examine the maturity analysis of tomato. The obtained results demonstrate that the fabricated conformable and scalable artificial fingertip shows different electrical property for ripe and unripe tomato. The artificial fingertip is compatible with the development of brain-like systems for artificial skin by obtaining periodic response during an applied load. Copyright © 2017. Published by Elsevier B.V.

Emergent geometric frustration of artificial magnetic skyrmion crystals

DOE PAGES

Ma, Fusheng; Reichhardt, Charles; Gan, Weiliang; ...

2016-10-05

Magnetic skyrmions have been receiving growing attention as potential information storage and magnetic logic devices since an increasing number of materials have been identified that support skyrmion phases. Explorations of artificial frustrated systems have led to new insights into controlling and engineering new emergent frustration phenomena in frustrated and disordered systems. Here, we propose a skyrmion spin ice, giving a unifying framework for the study of geometric frustration of skyrmion crystals (SCs) in a nonfrustrated artificial geometrical lattice as a consequence of the structural confinement of skyrmions in magnetic potential wells. The emergent ice rules from the geometrically frustrated SCsmore » highlight a novel phenomenon in this skyrmion system: emergent geometrical frustration. We demonstrate how SC topology transitions between a nonfrustrated periodic configuration and a frustrated icelike ordering can also be realized reversibly. The proposed artificial frustrated skyrmion systems can be annealed into different ice phases with an applied current-induced spin-transfer torque, including a long-range ordered ice rule obeying ground state, as-relaxed random state, biased state, and monopole state. In conclusion, the spin-torque reconfigurability of the artificial skyrmion ice states, difficult to achieve in other artificial spin ice systems, is compatible with standard spintronic device fabrication technology, which makes the semiconductor industrial integration straightforward.« less

Emergent geometric frustration of artificial magnetic skyrmion crystals

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

Ma, Fusheng; Reichhardt, Charles; Gan, Weiliang

Magnetic skyrmions have been receiving growing attention as potential information storage and magnetic logic devices since an increasing number of materials have been identified that support skyrmion phases. Explorations of artificial frustrated systems have led to new insights into controlling and engineering new emergent frustration phenomena in frustrated and disordered systems. Here, we propose a skyrmion spin ice, giving a unifying framework for the study of geometric frustration of skyrmion crystals (SCs) in a nonfrustrated artificial geometrical lattice as a consequence of the structural confinement of skyrmions in magnetic potential wells. The emergent ice rules from the geometrically frustrated SCsmore » highlight a novel phenomenon in this skyrmion system: emergent geometrical frustration. We demonstrate how SC topology transitions between a nonfrustrated periodic configuration and a frustrated icelike ordering can also be realized reversibly. The proposed artificial frustrated skyrmion systems can be annealed into different ice phases with an applied current-induced spin-transfer torque, including a long-range ordered ice rule obeying ground state, as-relaxed random state, biased state, and monopole state. In conclusion, the spin-torque reconfigurability of the artificial skyrmion ice states, difficult to achieve in other artificial spin ice systems, is compatible with standard spintronic device fabrication technology, which makes the semiconductor industrial integration straightforward.« less

University of Maryland MRSEC - Facilities: VTSTM

Science.gov Websites

MRSEC Templates Opportunities Search Home » Facilities » UHV-VT-STM Shared Experimental Facilities redistribute the contents without alteration is granted to educational institutions for non-profit

Specific DNA duplex formation at an artificial lipid bilayer: towards a new DNA biosensor technology.

PubMed

Werz, Emma; Korneev, Sergei; Montilla-Martinez, Malayko; Wagner, Richard; Hemmler, Roland; Walter, Claudius; Eisfeld, Jörg; Gall, Karsten; Rosemeyer, Helmut

2012-02-01

A novel technique is described which comprises a base-specific DNA duplex formation at a lipid bilayer-H(2) O-phase boundary layer. Two different probes of oligonucleotides both carrying a double-tailed lipid at the 5'-terminus were incorporated into stable artificial lipid bilayers separating two compartments (cis/trans-channel) of an optically transparent microfluidic sample carrier with perfusion capabilities. Both the cis- and trans-channels are filled with saline buffer. Injection of a cyanine-5-labeled target DNA sequence, which is complementary to only one of the oligonucleotide probes, into the cis-channel, followed by a thorough perfusion, leads to an immobilization of the labeled complementary oligonucleotide on the membrane as detected by single-molecule fluorescence spectroscopy and microscopy. In the case of fluorescent but non-complementary DNA sequences, no immobilized fluorescent oligonucleotide duplex could be detected on the membrane. This clearly verifies a specific duplex formation at the membrane interface. Copyright © 2012 Verlag Helvetica Chimica Acta AG, Zürich.

Advances in proton-exchange membranes for fuel cells: an overview on proton conductive channels (PCCs).

PubMed

Wu, Liang; Zhang, Zhenghui; Ran, Jin; Zhou, Dan; Li, Chuanrun; Xu, Tongwen

2013-04-14

Proton-exchange membranes (PEM) display unique ion-selective transport that has enabled a breakthrough in high-performance proton-exchange membrane fuel cells (PEMFCs). Elemental understanding of the morphology and proton transport mechanisms of the commercially available Nafion® has promoted a majority of researchers to tune proton conductive channels (PCCs). Specifically, knowledge of the morphology-property relationship gained from statistical and segmented copolymer PEMs has highlighted the importance of the alignment of PCCs. Furthermore, increasing efforts in fabricating and aligning artificial PCCs in field-aligned copolymer PEMs, nanofiber composite PEMs and mesoporous PEMs have set new paradigms for improvement of membrane performances. This perspective profiles the recent development of the channels, from the self-assembled to the artificial, with a particular emphasis on their formation and alignment. It concludes with an outlook on benefits of highly aligned PCCs for fuel cell operation, and gives further direction to develop new PEMs from a practical point of view.

Mach-Zehnder Interferometer Refractive Index Sensor Based on a Plasmonic Channel Waveguide

PubMed Central

Lee, Da Eun; Lee, Young Jin; Shin, Eunso; Kwon, Soon-Hong

2017-01-01

A Mach-Zehnder interferometer based on a plasmonic channel waveguide is proposed for refractive index sensing. The structure, with a small physical footprint of 20 × 120 μm2, achieved a high figure of merit of 294. The cut-off frequency behaviour in the plasmonic channel waveguide resulted in a flat dispersion curve, which induces a 1.8 times larger change of the propagation constant for the given refractive index change compared with previously reported results. PMID:29120381

Parametric optimization of multiple quality characteristics in laser cutting of Inconel-718 by using hybrid approach of multiple regression analysis and genetic algorithm

NASA Astrophysics Data System (ADS)

Shrivastava, Prashant Kumar; Pandey, Arun Kumar

2018-06-01

Inconel-718 has found high demand in different industries due to their superior mechanical properties. The traditional cutting methods are facing difficulties for cutting these alloys due to their low thermal potential, lower elasticity and high chemical compatibility at inflated temperature. The challenges of machining and/or finishing of unusual shapes and/or sizes in these materials have also faced by traditional machining. Laser beam cutting may be applied for the miniaturization and ultra-precision cutting and/or finishing by appropriate control of different process parameter. This paper present multi-objective optimization the kerf deviation, kerf width and kerf taper in the laser cutting of Incone-718 sheet. The second order regression models have been developed for different quality characteristics by using the experimental data obtained through experimentation. The regression models have been used as objective function for multi-objective optimization based on the hybrid approach of multiple regression analysis and genetic algorithm. The comparison of optimization results to experimental results shows an improvement of 88%, 10.63% and 42.15% in kerf deviation, kerf width and kerf taper, respectively. Finally, the effects of different process parameters on quality characteristics have also been discussed.

Ice and water on Newberry Volcano, central Oregon

USGS Publications Warehouse

Donnelly-Nolan, Julie M.; Jensen, Robert A.; O'Connor, Jim; Madin, Ian P.; Dorsey, Rebecca

2009-01-01

Newberry Volcano in central Oregon is dry over much of its vast area, except for the lakes in the caldera and the single creek that drains them. Despite the lack of obvious glacial striations and well-formed glacial moraines, evidence indicates that Newberry was glaciated. Meter-sized foreign blocks, commonly with smoothed shapes, are found on cinder cones as far as 7 km from the caldera rim. These cones also show evidence of shaping by flowing ice. In addition, multiple dry channels likely cut by glacial meltwater are common features of the eastern and western flanks of the volcano. On the older eastern flank of the volcano, a complex depositional and erosional history is recorded by lava flows, some of which flowed down channels, and interbedded sediments of probable glacial origin. Postglacial lava flows have subsequently filled some of the channels cut into the sediments. The evidence suggests that Newberry Volcano has been subjected to multiple glaciations.

Thermal responses of shape memory alloy artificial anal sphincters

NASA Astrophysics Data System (ADS)

Luo, Yun; Takagi, Toshiyuki; Matsuzawa, Kenichi

2003-08-01

This paper presents a numerical investigation of the thermal behavior of an artificial anal sphincter using shape memory alloys (SMAs) proposed by the authors. The SMA artificial anal sphincter has the function of occlusion at body temperature and can be opened with a thermal transformation induced deformation of SMAs to solve the problem of severe fecal incontinence. The investigation of its thermal behavior is of great importance in terms of practical use in living bodies as a prosthesis. In this work, a previously proposed phenomenological model was applied to simulate the thermal responses of SMA plates that had undergone thermally induced transformation. The numerical approach for considering the thermal interaction between the prosthesis and surrounding tissues was discussed based on the classical bio-heat equation. Numerical predictions on both in vitro and in vivo cases were verified by experiments with acceptable agreements. The thermal responses of the SMA artificial anal sphincter were discussed based on the simulation results, with the values of the applied power and the geometric configuration of thermal insulation as parameters. The results obtained in the present work provided a framework for the further design of SMA artificial sphincters to meet demands from the viewpoint of thermal compatibility as prostheses.

Compatibility of breeding for increased wood production and longterm sustainability: the genetic variation of seed orchard seed and associated risks.

Treesearch

R Johnson; S. Lipow

2002-01-01

Because breeding imposes strong artificial selection for a narrow suite of economically important traits, genetic variation is reduced in seedlings derived from operational seed orchards. Both quantitative genetics theory and studies of allozyme variation show that seed orchards contain most of the genetic diversity found in natural populations, although low-frequency...

Perceived Compatibility and the Adoption of B2C E-Commerce by Non-buyers

NASA Astrophysics Data System (ADS)

Hernández-García, Ángel; Iglesias-Pradas, Santiago; Chaparro-Peláez, Julián; Pascual-Miguel, Félix

The purpose of this article is to study the factors which affect the intention to buy online for users who have never made any prior purchase using the electronic channel, with special focus to the role of perceived compatibility. To do so, an adoption model for e-commerce was proposed on the basis of the Technology Adoption Model (TAM) and the Innovations Diffusion Theory (IDT). In order to validate the model, data gathered amongst Spanish consumers who had no experience using e-commerce, were analyzed using the partial least squares (PLS) method. The results have demonstrated the importance of perceived compatibility as a significant factor to foster non-buyers' adoption of electronic business-to-consumer e-commerce (eB2C).

Optogenetics and pharmacogenetics: principles and applications.

PubMed

Jiang, Jingwei; Cui, Huxing; Rahmouni, Kamal

2017-12-01

Remote and selective spatiotemporal control of the activity of neurons to regulate behavior and physiological functions has been a long-sought goal in system neuroscience. Identification and subsequent bioengineering of light-sensitive ion channels (e.g., channelrhodopsins, halorhodopsin, and archaerhodopsins) from the bacteria have made it possible to use light to artificially modulate neuronal activity, namely optogenetics. Recent advance in genetics has also allowed development of novel pharmacological tools to selectively and remotely control neuronal activity using engineered G protein-coupled receptors, which can be activated by otherwise inert drug-like small molecules such as the designer receptors exclusively activated by designer drug, a form of chemogenetics. The cutting-edge optogenetics and pharmacogenetics are powerful tools in neuroscience that allow selective and bidirectional modulation of the activity of defined populations of neurons with unprecedented specificity. These novel toolboxes are enabling significant advances in deciphering how the nervous system works and its influence on various physiological processes in health and disease. Here, we discuss the fundamental elements of optogenetics and chemogenetics approaches and some of the applications that yielded significant advances in various areas of neuroscience and beyond. Copyright © 2017 the American Physiological Society.

Scholasticism: Causes and Cures

ERIC Educational Resources Information Center

Mead, Lawrence M.

2011-01-01

The claim that faculty conduct research is one of the main justifications for the modern university. Supposedly, academe carries out important, cutting-edge inquiries in which society has an interest. In fact, states this author, research at American universities is becoming narrow and artificial, out of touch with social realities, and of…

Monitoring channel head erosion processes in response to an artificially induced abrupt base level change using time-lapse photography 2301

USDA-ARS?s Scientific Manuscript database

Headcut and channel extension in response to an abrupt base level change in 2004 of approximately 1m was studied in a 1.29 ha semiarid headwater drainage on the Walnut Gulch Experimental Watershed (WGEW) in southeastern Arizona, USA. Field observations and time-lapse photography were coupled with hy...

Silvies Valley Ranch, OR: using artificial beaver dams to restore incised streams

Treesearch

Rachael Davee; Susan Charnley; Hannah Gosnell

2017-01-01

The Silvies Valley Ranch is an example of using local innovation to combat the global problem of incised streams on rangelands. Incised channels reduce the flow between water in the channel and water in the surrounding soils, which reduces the vegetation available for wildlife habitat and cattle forage. One of the ranch owners, Scott Campbell, a doctor of veterinary...

Study of the Decomposition and Phase Transition of Uranium Nitride under UHV Conditions via TDS, XRD, SEM, and XPS.

PubMed

Wang, Xiaofang; Long, Zhong; Bin, Ren; Yang, Ruilong; Pan, Qifa; Li, Fangfang; Luo, Lizhu; Hu, Yin; Liu, Kezhao

2016-11-07

Uranium nitrides are among the most promising fuels for Generation IV nuclear reactors, but until now, very little has been known about their thermal stability properties under nonequilibrium conditions. In this work, thermal decomposition of nitrogen-rich uranium nitride (denoted as UN 2-x ) under ultrahigh-vacuum (UHV) conditions was investigated by thermal desorption spectroscopy (TDS). It has been shown that the nitrogen TDS spectrum consists of two peaks at about 723 and 1038 K. The X-ray diffraction, scanning electron microscopy, and X-ray photoelectron microscopy results indicate that UN 2-x (UN 2 phase) decomposed into the α-U 2 N 3 phase in the first step and the α-U 2 N 3 phase decomposed into the UN phase in the second step.

Four-probe measurements with a three-probe scanning tunneling microscope.

PubMed

Salomons, Mark; Martins, Bruno V C; Zikovsky, Janik; Wolkow, Robert A

2014-04-01

We present an ultrahigh vacuum (UHV) three-probe scanning tunneling microscope in which each probe is capable of atomic resolution. A UHV JEOL scanning electron microscope aids in the placement of the probes on the sample. The machine also has a field ion microscope to clean, atomically image, and shape the probe tips. The machine uses bare conductive samples and tips with a homebuilt set of pliers for heating and loading. Automated feedback controlled tip-surface contacts allow for electrical stability and reproducibility while also greatly reducing tip and surface damage due to contact formation. The ability to register inter-tip position by imaging of a single surface feature by multiple tips is demonstrated. Four-probe material characterization is achieved by deploying two tips as fixed current probes and the third tip as a movable voltage probe.

A Molecular Toolbox for Rapid Generation of Viral Vectors to Up- or Down-Regulate Neuronal Gene Expression in vivo

PubMed Central

White, Melanie D.; Milne, Ruth V. J.; Nolan, Matthew F.

2011-01-01

We introduce a molecular toolbox for manipulation of neuronal gene expression in vivo. The toolbox includes promoters, ion channels, optogenetic tools, fluorescent proteins, and intronic artificial microRNAs. The components are easily assembled into adeno-associated virus (AAV) or lentivirus vectors using recombination cloning. We demonstrate assembly of toolbox components into lentivirus and AAV vectors and use these vectors for in vivo expression of inwardly rectifying potassium channels (Kir2.1, Kir3.1, and Kir3.2) and an artificial microRNA targeted against the ion channel HCN1 (HCN1 miRNA). We show that AAV assembled to express HCN1 miRNA produces efficacious and specific in vivo knockdown of HCN1 channels. Comparison of in vivo viral transduction using HCN1 miRNA with mice containing a germ line deletion of HCN1 reveals similar physiological phenotypes in cerebellar Purkinje cells. The easy assembly and re-usability of the toolbox components, together with the ability to up- or down-regulate neuronal gene expression in vivo, may be useful for applications in many areas of neuroscience. PMID:21772812

Microwave drying remediation of petroleum-contaminated drill cuttings.

PubMed

Júnior, Irineu Petri; Martins, André Leibsohn; Ataíde, Carlos H; Duarte, Cláudio R

2017-07-01

The oil reservoir drilling phase generates contaminated cuttings with oil formation itself. These cuttings must be subjected to a decontamination process before being disposed of in the environment. Several technologies are cited in literature for the remediation of soil contaminated with oil or diesel, but none have been reported to remedy drill cuttings contaminated with oil from reservoir. The reservoir drill cuttings are a problem because its discharge is not allowed. The drying technology using microwave has shown promise in the decontamination of cuttings with non-aqueous base drilling fluid, conciliating good robustness and high removal efficiency. Considering the aspects mentioned previously, the application of heating and drying technology using microwave in the remediation of oil contaminated cuttings from well drill was studied. The influence of temperature, specific energy and initial content of water in the drying operation of the reservoir cuttings and of the drilling cuttings artificially contaminated with oil were analyzed. The results showed an influence of temperature in the drying of the cuttings, being necessary to reach the boiling temperature of heavier hydrocarbons to reach an efficient removal in the operation. The specific energy has a strong influence, reaching a total decontamination using 2.67 kWh/kg. The initial water content was effective in removing oil, reducing the residual level of oil with the increase of initial content of water. It also modifies the temperature profiles of the kinetic-warming of the contaminated cuttings. Both the technology and the equipment used proved effective for obtaining total decontamination of oil from the cuttings. Copyright © 2017 Elsevier Ltd. All rights reserved.

System to measure accurate temperature dependence of electric conductivity down to 20 K in ultrahigh vacuum.

PubMed

Sakai, C; Takeda, S N; Daimon, H

2013-07-01

We have developed the new in situ electrical-conductivity measurement system which can be operated in ultrahigh vacuum (UHV) with accurate temperature measurement down to 20 K. This system is mainly composed of a new sample-holder fixing mechanism, a new movable conductivity-measurement mechanism, a cryostat, and two receptors for sample- and four-probe holders. Sample-holder is pushed strongly against the receptor, which is connected to a cryostat, by using this new sample-holder fixing mechanism to obtain high thermal conductivity. Test pieces on the sample-holders have been cooled down to about 20 K using this fixing mechanism, although they were cooled down to only about 60 K without this mechanism. Four probes are able to be touched to a sample surface using this new movable conductivity-measurement mechanism for measuring electrical conductivity after making film on substrates or obtaining clean surfaces by cleavage, flashing, and so on. Accurate temperature measurement is possible since the sample can be transferred with a thermocouple and∕or diode being attached directly to the sample. A single crystal of Bi-based copper oxide high-Tc superconductor (HTSC) was cleaved in UHV to obtain clean surface, and its superconducting critical temperature has been successfully measured in situ. The importance of in situ measurement of resistance in UHV was demonstrated for this HTSC before and after cesium (Cs) adsorption on its surface. The Tc onset increase and the Tc offset decrease by Cs adsorption were observed.

The preparation of pure niobium for neutron dosimetry purposes

NASA Astrophysics Data System (ADS)

Schulze, Klaus; Krehl, Michael

1985-06-01

A technique is described for the preparation of high purity niobium for use in fast neutron dosimetry. Based on results of known purification processes for niobium, an optimized method has been developed, consisting of: (1) a double electrolytic refining in an eutectic lithium-, sodium-, potassium-fluoride melt, containing fluoro-potassium niobate (K 2NbF 7), (2) electron beam float zone melting (EBFZM) in ultra high vacuum (UHV) and (3) UHV treatments. Starting with EBFZM of niobium of commercial quality (140 μg/g Ta, 35 μg/g W) the tantalum and tungsten contents were reduced by a first electrolysis to approximately 4 and 4 × 10 -2 μg/g, respectively. For a second electrolytic refining using a salt bath with extremely low tantalum and tungsten contents, this material was subjected to an additional EBFZM process. The niobium metal produced by this step was three times zone melted to reduce those elements (e.g. Fe, Co, Ni, O, N) which increased during the electrolyses. Material produced by this technique has impurity concentrations below 0.4 μg/g of tantalum and 10 -2 μg/g of tungsten. The concentration of the interstitials (C, O, N except H) is below the detection limit of classical analytical methods. A further reduction of the interstitials by annealing treatments in UHV of this material resulted in an electrical residual resistivity ratio (RRR) ρ(295 K)/ ρ(4.2 K) = 24 500 indicating an impurity concentration far below 1 μg/g.

Not-Post-Peierls compatibility under noisy channels

NASA Astrophysics Data System (ADS)

Ducuara, Andrés F.; Susa, Cristian E.; Reina, John H.

2017-06-01

The Pusey-Barrett-Rudolph (PBR) theorem deals with the realism of the quantum states. It establishes that every pure quantum state is real, in the context of quantum ontological models. Specifically, by guaranteeing the property of not-Post-Peierls (\

Technological capabilities of increasing surface quality of workpieces made of titanium alloy VT22 and stability of surface grinding

NASA Astrophysics Data System (ADS)

Soler, Ya I.; Salov, V. M.; Mai, D. S.

2018-03-01

Surface grinding of flat workpieces made of alloy VT22 was conducted by the periphery of a highly porous wheel (HPW) from cubic boron nitride CBN30 B107 100 OV K27 КF40 with three processing techniques (ij). They are 10 - cross-feed per stroke, HPW cutting into a workpiece changes alternately from up to down; 12 – cross-feed per double stroke during the up HPW cutting-in at the working stroke; 22 – cross-feed per double stroke during the down HPW cutting-in at the working stroke. With the involvement of artificial neural network models, it was revealed that to improve the quality of surfaces and stability of its formation, grinding should be conducted if ij = 12.

Intersecting Channels near Olympica Fossae

NASA Image and Video Library

2016-09-21

This complicated area contains various types of channels, pits and fractures. We can determine the relative ages of the pits and channels based on which features cross-cut others. Older channels appear smooth-edged and shallow. Younger channels and pits are deeper and more sharp-edged, as well as less sinuous than the shallower channels. What caused this array of various channels and intersecting pits? This region is covered in vast lava flows. The collapse pits here may be collapsed lava tubes or where overlying rock "drained" into voids created by extensional faulting. The older smoother channel that seems to source from this region may have carried an outflow of groundwater. It continues on for over 100 kilometers (62 miles). The orientation and shapes of these features make an interesting geological puzzle. http://photojournal.jpl.nasa.gov/catalog/PIA21066

Panama Canal Zone as seen from STS-62

NASA Image and Video Library

1994-03-05

STS062-85-095 (4-18 March 1994) --- Gatun Lake and the forested Panama Canal Zone can be seen in this north northwest-looking low oblique photograph obtained in March 1994. The shipping chanel of the canal is 82.4 kilometers (51.2 miles) long, though the canal zone is only 65 kilometers (40 miles) long. The width of the canal zones extends generally 8 kilometers (5 miles) on either side of the shipping channel, except near Madden Lake. The canal connects the Atlantic Ocean (coastal city of Colon) with the Pacific Ocean near Panama City in a line that takes a northwest to southeast course because of the configuration of the isthmus. The canal zigzags across the isthmus to take advantage of the geographic features of the area such as the Chagres River. The controlled water supply for the canal is provided by the three artificial lakes: Gatun near the Atlantic terminus, Miraflores near the Pacific terminus and Madden about halfway across the isthmus. Gatun is the largest of the three lakes covering an area of 429 square kilometers (165 square miles). In the midst of this lake is Barro Colorado Island, a world-famous wild game perserve. Madden Lake was built as a large supplemental reservoir to keep water levels up in the canal during the dry season. All three lakes are vital sources of water for maintaining the ship channel over the continental divide (Gaillard Cut) and for regulating the flow of water that enables hugh vessels to be lifted and lowered in massive locks.

Artificial stone dust-induced functional and inflammatory abnormalities in exposed workers monitored quantitatively by biometrics.

PubMed

Ophir, Noa; Shai, Amir Bar; Alkalay, Yifat; Israeli, Shani; Korenstein, Rafi; Kramer, Mordechai R; Fireman, Elizabeth

2016-01-01

The manufacture of kitchen and bath countertops in Israel is based mainly on artificial stone that contains 93% silica as natural quartz, and ∼3500 workers are involved in cutting and processing it. Artificial stone produces high concentrations of silica dust. Exposure to crystalline silica may cause silicosis, an irreversible lung disease. Our aim was to screen exposed workers by quantitative biometric monitoring of functional and inflammatory parameters. 68 exposed artificial stone workers were compared to 48 nonexposed individuals (controls). Exposed workers filled in questionnaires, and all participants underwent pulmonary function tests and induced sputum analyses. Silica was quantitated by a Niton XL3 X-ray fluorescence spectrometer. Pulmonary function test results of exposed workers were significantly lower and induced sputa showed significantly higher neutrophilic inflammation compared to controls; both processes were slowed down by the use of protective measures in the workplace. Particle size distribution in induced sputum samples of exposed workers was similar to that of artificial stone dust, which contained aluminium, zirconium and titanium in addition to silica. In conclusion, the quantitation of biometric parameters is useful for monitoring workers exposed to artificial stone in order to avoid deterioration over time.

Active Brownian motion in a narrow channel

NASA Astrophysics Data System (ADS)

Ao, X.; Ghosh, P. K.; Li, Y.; Schmid, G.; Hänggi, P.; Marchesoni, F.

2014-12-01

We review recent advances in rectification control of artificial microswimmers, also known as Janus particles, diffusing along narrow, periodically corrugated channels. The swimmer self-propulsion mechanism is modeled so as to incorporate a nonzero torque (propulsion chirality). We first summarize the effects of chirality on the autonomous current of microswimmers freely diffusing in channels of different geometries. In particular, left-right and upside-down asymmetric channels are shown to exhibit different transport properties. We then report new results on the dependence of the diffusivity of chiral microswimmers on the channel geometry and their own self-propulsion mechanism. The self-propulsion torque turns out to play a key role as a transport control parameter.

Board-level optical clock signal distribution using Si CMOS-compatible polyimide-based 1- to 48-fanout H-tree

NASA Astrophysics Data System (ADS)

Wu, Linghui; Bihari, Bipin; Gan, Jianhua; Chen, Ray T.; Tang, Suning

1998-08-01

Si-CMOS compatible polymer-based waveguides for optoelectronic interconnects and packaging have been fabricated and characterized. A 1-to-48 fanout optoelectronic interconnection layer (OIL) structure based on Ultradel 9120/9020 for the high-speed massive clock signal distribution for a Cray T-90 supercomputer board has been constructed. The OIL employs multimode polymeric channel waveguides in conjunction with surface-normal waveguide output coupler and 1-to-2 splitter. A total insertion loss of 7.98 dB at 850 nm was measured experimentally.

Rate-Compatible Protograph LDPC Codes

NASA Technical Reports Server (NTRS)

Nguyen, Thuy V. (Inventor); Nosratinia, Aria (Inventor); Divsalar, Dariush (Inventor)

2014-01-01

Digital communication coding methods resulting in rate-compatible low density parity-check (LDPC) codes built from protographs. Described digital coding methods start with a desired code rate and a selection of the numbers of variable nodes and check nodes to be used in the protograph. Constraints are set to satisfy a linear minimum distance growth property for the protograph. All possible edges in the graph are searched for the minimum iterative decoding threshold and the protograph with the lowest iterative decoding threshold is selected. Protographs designed in this manner are used in decode and forward relay channels.

High-Speed Edge Trimming of CFRP and Online Monitoring of Performance of Router Tools Using Acoustic Emission

PubMed Central

Prakash, Rangasamy; Krishnaraj, Vijayan; Zitoune, Redouane; Sheikh-Ahmad, Jamal

2016-01-01

Carbon fiber reinforced polymers (CFRPs) have found wide-ranging applications in numerous industrial fields such as aerospace, automotive, and shipping industries due to their excellent mechanical properties that lead to enhanced functional performance. In this paper, an experimental study on edge trimming of CFRP was done with various cutting conditions and different geometry of tools such as helical-, fluted-, and burr-type tools. The investigation involves the measurement of cutting forces for the different machining conditions and its effect on the surface quality of the trimmed edges. The modern cutting tools (router tools or burr tools) selected for machining CFRPs, have complex geometries in cutting edges and surfaces, and therefore a traditional method of direct tool wear evaluation is not applicable. An acoustic emission (AE) sensing was employed for on-line monitoring of the performance of router tools to determine the relationship between AE signal and length of machining for different kinds of geometry of tools. The investigation showed that the router tool with a flat cutting edge has better performance by generating lower cutting force and better surface finish with no delamination on trimmed edges. The mathematical modeling for the prediction of cutting forces was also done using Artificial Neural Network and Regression Analysis. PMID:28773919

Operational rate-distortion performance for joint source and channel coding of images.

PubMed

Ruf, M J; Modestino, J W

1999-01-01

This paper describes a methodology for evaluating the operational rate-distortion behavior of combined source and channel coding schemes with particular application to images. In particular, we demonstrate use of the operational rate-distortion function to obtain the optimum tradeoff between source coding accuracy and channel error protection under the constraint of a fixed transmission bandwidth for the investigated transmission schemes. Furthermore, we develop information-theoretic bounds on performance for specific source and channel coding systems and demonstrate that our combined source-channel coding methodology applied to different schemes results in operational rate-distortion performance which closely approach these theoretical limits. We concentrate specifically on a wavelet-based subband source coding scheme and the use of binary rate-compatible punctured convolutional (RCPC) codes for transmission over the additive white Gaussian noise (AWGN) channel. Explicit results for real-world images demonstrate the efficacy of this approach.

Entropy Splitting for High Order Numerical Simulation of Compressible Turbulence

NASA Technical Reports Server (NTRS)

Sandham, N. D.; Yee, H. C.; Kwak, Dochan (Technical Monitor)

2000-01-01

A stable high order numerical scheme for direct numerical simulation (DNS) of shock-free compressible turbulence is presented. The method is applicable to general geometries. It contains no upwinding, artificial dissipation, or filtering. Instead the method relies on the stabilizing mechanisms of an appropriate conditioning of the governing equations and the use of compatible spatial difference operators for the interior points (interior scheme) as well as the boundary points (boundary scheme). An entropy splitting approach splits the inviscid flux derivatives into conservative and non-conservative portions. The spatial difference operators satisfy a summation by parts condition leading to a stable scheme (combined interior and boundary schemes) for the initial boundary value problem using a generalized energy estimate. A Laplacian formulation of the viscous and heat conduction terms on the right hand side of the Navier-Stokes equations is used to ensure that any tendency to odd-even decoupling associated with central schemes can be countered by the fluid viscosity. A special formulation of the continuity equation is used, based on similar arguments. The resulting methods are able to minimize spurious high frequency oscillation producing nonlinear instability associated with pure central schemes, especially for long time integration simulation such as DNS. For validation purposes, the methods are tested in a DNS of compressible turbulent plane channel flow at a friction Mach number of 0.1 where a very accurate turbulence data base exists. It is demonstrated that the methods are robust in terms of grid resolution, and in good agreement with incompressible channel data, as expected at this Mach number. Accurate turbulence statistics can be obtained with moderate grid sizes. Stability limits on the range of the splitting parameter are determined from numerical tests.

Advanced porous electrodes with flow channels for vanadium redox flow battery

NASA Astrophysics Data System (ADS)

Bhattarai, Arjun; Wai, Nyunt; Schweiss, Ruediger; Whitehead, Adam; Lim, Tuti M.; Hng, Huey Hoon

2017-02-01

Improving the overall energy efficiency by reducing pumping power and improving flow distribution of electrolyte, is a major challenge for developers of flow batteries. The use of suitable channels can improve flow distribution through the electrodes and reduce flow resistance, hence reducing the energy consumption of the pumps. Although several studies of vanadium redox flow battery have proposed the use of bipolar plates with flow channels, similar to fuel cell designs, this paper presents the use of flow channels in the porous electrode as an alternative approach. Four types of electrodes with channels: rectangular open channel, interdigitated open cut channel, interdigitated circular poked channel and cross poked circular channels, are studied and compared with a conventional electrode without channels. Our study shows that interdigitated open channels can improve the overall energy efficiency up to 2.7% due to improvement in flow distribution and pump power reduction while interdigitated poked channel can improve up to 2.5% due to improvement in flow distribution.

Nanostructuring of conduction channels in (In,Ga)As-InP heterostructures: Overcoming carrier generation caused by Ar ion milling

NASA Astrophysics Data System (ADS)

Hortelano, V.; Weidlich, H.; Semtsiv, M. P.; Masselink, W. T.; Ramsteiner, M.; Jahn, U.; Biermann, K.; Takagaki, Y.

2018-04-01

Nanometer-sized channels are fabricated in (In,Ga)As-InP heterostructures using Ar ion milling. The ion milling causes spontaneous creation of nanowires, and moreover, electrical conduction of the surface as carriers is generated by sputtering-induced defects. We demonstrate a method to restore electrical isolation in the etched area that is compatible with the presence of the nanochannels. We remove the heavily damaged surface layer using a diluted HCl solution and subsequently recover the crystalline order in the moderately damaged part by annealing. We optimize the HCl concentration to make the removal stop on its own before reaching the conduction channel part. The lateral depletion in the channels is shown to be almost absent.

Designing for the Next Web.

ERIC Educational Resources Information Center

Bremser, Wayne

1998-01-01

Discusses how to choose from the available interactive graphic-design possibilities for the World Wide Web. Compatibility and appropriateness are discussed; and DHTML (Dynamic Hypertext Markup Language), Java, CSS (Cascading Style Sheets), plug-ins, ActiveX, and Push and channel technologies are described. (LRW)

Morphological adjustments in a meandering reach of the middle Yangtze River caused by severe human activities

NASA Astrophysics Data System (ADS)

Zhou, Meirong; Xia, Junqiang; Lu, Jinyou; Deng, Shanshan; Lin, Fenfen

2017-05-01

In the past 50 years, the Shishou reach in the middle Yangtze River underwent significant channel evolution owing to the implementation of an artificial cutoff, the construction of bank revetment works and the operation of the Three Gorges Project (TGP). Based on the measured hydrological data and topographic data, the processes of channel evolution in this reach were investigated mainly from the adjustments in planform and cross-sectional geometries. The variation in planform geometry obtained in this study indicates that (i) the artificial cutoff at Zhongzhouzi caused the river regime to adjust drastically, with the mean rate of thalweg migration at reach scale of 42.0 m/a over the period 1966-1975; (ii) then the effect of this artificial cutoff reduced gradually, with the mean migration rate decreasing to < 30 m/a in 1975-1993, while it increased to > 40 m/a owing to the occurrence of high water levels in 1993-1998; and (iii) the average annual rate of thalweg migration decreased to 29.3 m/a because of the impacts of various bank protection engineering and the TGP operation during the period 2002-2015. However, remarkable thalweg migration processes still occurred in local regions after the TGP operation, which resulted in significant bankline migration in local reaches of Beimenkou, Shijiatai, and Tiaoxiankou. In addition, the adjustments of bankfull channel geometry were investigated at section and reach scales after the TGP operation. Calculated results show that lateral channel migration in this reach was restricted by various river regulation works and that channel evolution was mainly characterized by an increase in bankfull depth and cross-sectional area. Empirical relationships were developed between the reach-scale bankfull dimensions (depth and area), the bankfull widths at specified sections, and the previous 5-year average fluvial erosion intensity during flood seasons, with high correlation degrees between them being obtained.

Poly(aniline) nanowires in sol-gel coated ITO: A pH-responsive substrate for planar supported lipid bilayers

PubMed Central

Ge, Chenhao; Orosz, Kristina S.; Armstrong, Neal R.; Saavedra, S. Scott

2011-01-01

Facilitated ion transport across an artificial lipid bilayer coupled to a solid substrate is a function common to several types of bioelectronic devices based on supported membranes, including biomimetic fuel cells and ion channel biosensors. Described here is fabrication of a pH-sensitive transducer composed of a porous sol-gel layer derivatized with poly(aniline) (PANI) nanowires grown from an underlying planar indium-tin oxide (ITO) electrode. The upper sol-gel surface is hydrophilic, smooth, and compatible with deposition of a planar supported lipid bilayer (PSLB) formed via vesicle fusion. Conducting tip AFM was used to show that the PANI wires are connected to the ITO, which convert this electrode into a potentiometric pH sensor. The response to changes in the pH of the buffer contacting the PANI nanowire/sol-gel/ITO electrode is blocked by the very low ion permeability of the overlying, fluid PSLB. The feasibility of using this assembly to monitor facilitated proton transport across the PSLB was demonstrated by doping the membrane with lipophilic ionophores that respond to a transmembrane pH gradient, which produced an apparent proton permeability several orders of magnitude greater than values measured for undoped lipid bilayers. PMID:21707069

The self-compatibility mechanism in Brassica napus L. is applicable to F1 hybrid breeding.

PubMed

Tochigi, Takahiro; Udagawa, Hisashi; Li, Feng; Kitashiba, Hiroyasu; Nishio, Takeshi

2011-08-01

Brassica napus, an allopolyploid species having the A genome of B. rapa and the C genome of B. oleracea, is self-compatible, although both B. rapa and B. oleracea are self-incompatible. We have previously reported that SP11/SCR alleles are not expressed in anthers, while SRK alleles are functional in the stigma in B. napus cv. 'Westar', which has BnS-1 similar to B. rapa S-47 and BnS-6 similar to B. oleracea S-15. This genotype is the most frequent S genotype in B. napus, and we hypothesized that the loss of the function of SP11 is the primary cause of the self-compatibility of 'Westar'. To verify this hypothesis, we transformed 'Westar' plants with the SP11 allele of B. rapa S-47. All the transgenic plants and their progeny were completely self-incompatible, demonstrating self-compatibility to be due to the S haplotype having the non-functional SP11 allele in the A genome, which suppresses a functional recessive SP11 allele in the C genome. An artificially synthesized B. napus line having two recessive SP11 alleles was developed by interspecific hybridization between B. rapa and B. oleracea. This line was self-incompatible, but F(1) hybrids between this line and 'Westar' were self-compatible. These results suggest that the self-compatibility mechanism of 'Westar' is applicable to F(1) seed production in B. napus.

Ion channels in artificial bolaamphiphile membranes deposited on sensor chips: optical detection in an ion-channel-based biosensor

NASA Astrophysics Data System (ADS)

Schalkhammer, Thomas G. M.; Weiss-Wichert, Christof; Smetazko, Michaela M.; Valina-Saba, Miriam

1997-06-01

Signal amplification using labels should be replaced by a technique monitoring the biochemical binding event directly. The use of a ligand coupled to an artificial gated membrane ion channel is a new promising strategy. Binding of protein- or DNA/RNA-analytes at ligand modified peptide channels results in an on/off-response of the channel current due to channel closure or distortion. The sensor consists of stable transmembrane channels with a ligand bound covalently at the peptide channel entrance, a sensor chip with a photostructurized hydrophobic polymer frame, a hydrophilic ion conducting membrane support, a lipid membrane incorporating the engineered ion channels, and a current amplifier or a sensitive fluorescence monitor. Detection of channel opening or closure can ether be obtained by directly monitoring membrane conductivity or a transient change of pH or ion concentration within the membrane compartment. This change can be induced by electrochemical or optical means and its decay is directly correlated to the permeability of the membrane. The ion concentration in the sub membrane compartment was monitored by incorporation of fluorescent indicator dyes. To obtain the stable sensor membrane the lipid layer had to be attached on a support and the floating of the second lipid membrane on top of the first one had to be prevented. Both problems do not occur using our new circular C44-C76 bolaamphiphilic lipids consisting of a long hydrophobic core region and two hydrophilic heads. Use of maleic ester-head groups enabled us to easily modify the lipids with amines, thioles, alcohols, phosphates, boronic acid as well as fluorescent dyes. The properties of these membranes were studied using LB and fluorescence techniques. Based on this detection principle miniaturized sensor chips with significantly enhanced sensitivity and large multi analyte arrays are under construction.

A comparison of the thermal and hydraulic performances between miniature pin fin heat sink and microchannel heat sink with zigzag flow channel together with using nanofluids

NASA Astrophysics Data System (ADS)

Duangthongsuk, Weerapun; Wongwises, Somchai

2018-05-01

In this study, a comparison of the convective heat transfer, pressure drop, and performance index characteristics of heat sinks with a miniature circular pin-fin inline arrangement (MCFHS) and a zigzag flow channel with single cross-cut structures (CCZ-HS) is presented. SiO2-water nanofluids with different particle concentrations are used as the coolant. The effects of the heat sink type, particle concentration and fluid flow rate on the thermal and hydraulic performances are evaluated. The testing conditions are performed at the wall heat fluxes of 10 to 60 kW/m2 and at a mass flow rate ranging from 0.18 to 0.6 kg/s. The dimension of heat sinks is equally designed at 28 × 33 mm. The heat transfer area of MCFHS and of CCZ-HS is 1430 and 1238 mm2, respectively. Similarly, the hydraulic diameter of the flow channel of MCFHS and of CCZ-HS is 1.2 and 1.0 mm, respectively. The measured data indicate that the cooling performances of CCZ-HS are about 24-55% greater than that of MCFHS. The effects of the channel diameter and single cross-cut of the flow channel are more dominant than the effects of the fin structure and heat transfer area.

CO2 Permeability of Biological Membranes and Role of CO2 Channels

PubMed Central

Endeward, Volker; Arias-Hidalgo, Mariela; Al-Samir, Samer; Gros, Gerolf

2017-01-01

We summarize here, mainly for mammalian systems, the present knowledge of (a) the membrane CO2 permeabilities in various tissues; (b) the physiological significance of the value of the CO2 permeability; (c) the mechanisms by which membrane CO2 permeability is modulated; (d) the role of the intracellular diffusivity of CO2 for the quantitative significance of cell membrane CO2 permeability; (e) the available evidence for the existence of CO2 channels in mammalian and artificial systems, with a brief view on CO2 channels in fishes and plants; and, (f) the possible significance of CO2 channels in mammalian systems. PMID:29064458

An underlap field-effect transistor for electrical detection of influenza

NASA Astrophysics Data System (ADS)

Lee, Kwang-Won; Choi, Sung-Jin; Ahn, Jae-Hyuk; Moon, Dong-Il; Park, Tae Jung; Lee, Sang Yup; Choi, Yang-Kyu

2010-01-01

An underlap channel-embedded field-effect transistor (FET) is proposed for label-free biomolecule detection. Specifically, silica binding protein fused with avian influenza (AI) surface antigen and avian influenza antibody (anti-AI) were designed as a receptor molecule and a target material, respectively. The drain current was significantly decreased after the binding of negatively charged anti-AI on the underlap channel. A set of control experiments supports that only the biomolecules on the underlap channel effectively modulate the drain current. With the merits of a simple fabrication process, complementary metal-oxide-semiconductor compatibility, and enhanced sensitivity, the underlap FET could be a promising candidate for a chip-based biosensor.

Small wash functions and effects of their disturbance on vegetation of a Mojave Desert bajada

NASA Astrophysics Data System (ADS)

Sandquist, D. R.; Bedford, D.; Macias, M.; Miller, D. M.; Newlander, A.; Schwinning, S.

2011-12-01

The extensive network of small washes and channels that pervades most desert bajadas usually represents only a small proportion of the bajada's spatial area and are usually devoid of vegetation. However, these channels may be the most important geomorphic feature influencing vegetation properties and processes in arid lands. To evaluate the functional influence of small channels on the vegetation of a Mojave Desert bajada, we conducted a series of observations and experiments across a ~100 year old linear disturbance (railroad and parallel road) that disrupts the natural flow path of the channel network. In areas below the railroad where flow has been either increased due to channel diversion and coalescence through culverts, or cut off due to diversion, plant community structure and cover has changed relative to undisturbed areas. Plant physiological responses to simulated runoff experiments, conducted in active (undisturbed) and inactive (cut-off) channels, revealed subtle differences that, when compounded through time, are likely to contribute to these shifts in vegetation. Measurements of water potential on the two dominant plant species, Larrea tridentata and Ambrosia dumosa, indicate that Larrea within 3 m of a channel, and Ambrosia within 2 m, access water from the channel. However, the water potential responses were less pronounced, shorter in duration and more variable for plants adjacent to inactive channels than for those near active channels. Stomatal conductance and sap-flow measurements on Larrea corroborated these findings, suggesting that root patterns and functions associated with channels are altered when water flow is reduced or eliminated over extended periods of time. These findings indicate that disturbance of small desert washes and channels can lead to vegetation shifts through time with consequences that are not yet fully understood. Small desert washes and channels may represent a minor spatial component of the vast bajada landscape, but runoff and higher infiltration rates, coupled with the breadth of their spatial influence on adjacent plants, suggests that these modest geomorphic features may have a disproportionate impact on plant function and community properties in arid ecosystems.

Dark channels in resonant tunneling transport through artificial atoms.

PubMed

Vaz, Eduardo; Kyriakidis, Jordan

2008-07-14

We investigate sequential tunneling through a multilevel quantum dot confining multiple electrons in the regime where several channels are available for transport within the bias window. By analyzing solutions to the master equations of the reduced density matrix, we give general conditions on when the presence of a second transport channel in the bias window quenches transport through the quantum dot. These conditions are in terms of distinct tunneling anisotropies which may aid in explaining the occurrence of negative differential conductance in quantum dots in the nonlinear regime.

Influence of Surface Features for Increased Heat Dissipation on Tool Wear

PubMed Central

Beno, Tomas; Hoier, Philipp; Wretland, Anders

2018-01-01

The critical problems faced during the machining process of heat resistant superalloys, (HRSA), is the concentration of heat in the cutting zone and the difficulty in dissipating it. The concentrated heat in the cutting zone has a negative influence on the tool life and surface quality of the machined surface, which in turn, contributes to higher manufacturing costs. This paper investigates improved heat dissipation from the cutting zone on the tool wear through surface features on the cutting tools. Firstly, the objective was to increase the available surface area in high temperature regions of the cutting tool. Secondly, multiple surface features were fabricated for the purpose of acting as channels in the rake face to create better access for the coolant to the proximity of the cutting edge. The purpose was thereby to improve the cooling of the cutting edge itself, which exhibits the highest temperature during machining. These modified inserts were experimentally investigated in face turning of Alloy 718 with high-pressure coolant. Overall results exhibited that surface featured inserts decreased flank wear, abrasion of the flank face, cutting edge deterioration and crater wear probably due to better heat dissipation from the cutting zone. PMID:29693579

21 CFR 133.118 - Colby cheese.

Code of Federal Regulations, 2012 CFR

2012-04-01

... harmless lactic-acid-producing bacteria, present in such milk or added thereto. Harmless artificial... the methods prescribed in § 133.5 (a), (b), and (d). If the milk used is not pasteurized, the cheese.../catalase as provided in § 133.113(a)(3). (d)(1) Colby cheese in the form of slices or cuts may have added...

21 CFR 133.118 - Colby cheese.

Code of Federal Regulations, 2013 CFR

2013-04-01

... harmless lactic-acid-producing bacteria, present in such milk or added thereto. Harmless artificial... the methods prescribed in § 133.5 (a), (b), and (d). If the milk used is not pasteurized, the cheese.../catalase as provided in § 133.113(a)(3). (d)(1) Colby cheese in the form of slices or cuts may have added...

21 CFR 133.118 - Colby cheese.

Code of Federal Regulations, 2014 CFR

2014-04-01

... harmless lactic-acid-producing bacteria, present in such milk or added thereto. Harmless artificial... the methods prescribed in § 133.5 (a), (b), and (d). If the milk used is not pasteurized, the cheese.../catalase as provided in § 133.113(a)(3). (d)(1) Colby cheese in the form of slices or cuts may have added...

Vertical Integration of System-on-Chip Concepts in the Digital Design Curriculum

ERIC Educational Resources Information Center

Tang, Ying; Head, L. M.; Ramachandran, R. P.; Chatman, L. M.

2011-01-01

The rapid evolution of System-on-Chip (SoC) challenges academic curricula to keep pace with multidisciplinary/interdisciplinary system thinking. This paper presents a curricular prototype that cuts across artificial course boundaries and provides a meaningful exploration of diverse facets of SoC design. Specifically, experimental contents of a…

Membrane-Based Emitter for Coupling Microfluidics with Ultrasensitive Nanoelectrospray Ionization-Mass Spectrometry

PubMed Central

Sun, Xuefei; Kelly, Ryan T.; Tang, Keqi; Smith, Richard D.

2011-01-01

An integrated poly(dimethylsiloxane) (PDMS) membrane-based microfluidic emitter for high performance nanoelectrospray ionization-mass spectrometry (nanoESI-MS) has been fabricated and evaluated. The ~100-μm-thick emitter was created by cutting a PDMS membrane that protrudes beyond the bulk substrate. The reduced surface area at the emitter enhances the electric field and reduces wetting of the surface by the electrospray solvent. As such, the emitter enables highly stable electrosprays at flow rates as low as 10 nL/min, and is compatible with electrospray solvents containing a large organic component (e.g., 90% methanol). This approach enables facile emitter construction, and provides excellent stability, reproducibility and sensitivity, as well as compatibility with multilayer soft lithography. PMID:21657269

Gauge-invariance and infrared divergences in the luminosity distance

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

Biern, Sang Gyu; Yoo, Jaiyul, E-mail: sgbiern@physik.uzh.ch, E-mail: jyoo@physik.uzh.ch

2017-04-01

Measurements of the luminosity distance have played a key role in discovering the late-time cosmic acceleration. However, when accounting for inhomogeneities in the Universe, its interpretation has been plagued with infrared divergences in its theoretical predictions, which are in some cases used to explain the cosmic acceleration without dark energy. The infrared divergences in most calculations are artificially removed by imposing an infrared cut-off scale. We show that a gauge-invariant calculation of the luminosity distance is devoid of such divergences and consistent with the equivalence principle, eliminating the need to impose a cut-off scale. We present proper numerical calculations ofmore » the luminosity distance using the gauge-invariant expression and demonstrate that the numerical results with an ad hoc cut-off scale in previous calculations have negligible systematic errors as long as the cut-off scale is larger than the horizon scale. We discuss the origin of infrared divergences and their cancellation in the luminosity distance.« less

Theoretical Investigations on the Influence of Artificially Altered Rock Mass Properties on Mechanical Excavation

NASA Astrophysics Data System (ADS)

Hartlieb, Philipp; Bock, Stefan

2018-03-01

This study presents a theoretical analysis of the influence of the rock mass rating on the cutting performance of roadheaders. Existing performance prediction models are assessed for their suitability for forecasting the influence of pre-damaging the rock mass with alternative methods like lasers or microwaves, prior to the mechanical excavation process. Finally, the RMCR model was chosen because it is the only reported model incorporating a range of rock mass properties into its calculations. The results show that even very tough rocks could be mechanically excavated if the occurrence, orientation and condition of joints are favourable for the cutting process. The calculated improvements in the cutting rate (m3/h) are up to 350% for the most favourable cases. In case of microwave irradiation of hard rocks with an UCS of 200 MPa, a reasonable improvement in the performance by 120% can be achieved with as little as an extra 0.7 kWh/m3 (= 1% more energy) compared to cutting only.

Symbiotic adaptations in the fungal cultivar of leaf-cutting ants.

PubMed

De Fine Licht, Henrik H; Boomsma, Jacobus J; Tunlid, Anders

2014-12-01

Centuries of artificial selection have dramatically improved the yield of human agriculture; however, strong directional selection also occurs in natural symbiotic interactions. Fungus-growing attine ants cultivate basidiomycete fungi for food. One cultivar lineage has evolved inflated hyphal tips (gongylidia) that grow in bundles called staphylae, to specifically feed the ants. Here we show extensive regulation and molecular signals of adaptive evolution in gene trancripts associated with gongylidia biosynthesis, morphogenesis and enzymatic plant cell wall degradation in the leaf-cutting ant cultivar Leucoagaricus gongylophorus. Comparative analysis of staphylae growth morphology and transcriptome-wide expressional and nucleotide divergence indicate that gongylidia provide leaf-cutting ants with essential amino acids and plant-degrading enzymes, and that they may have done so for 20-25 million years without much evolutionary change. These molecular traits and signatures of selection imply that staphylae are highly advanced coevolutionary organs that play pivotal roles in the mutualism between leaf-cutting ants and their fungal cultivars.

Missing domesticated plant forms: can artificial selection fill the gap?

PubMed Central

Van Tassel, David L; DeHaan, Lee R; Cox, Thomas S

2010-01-01

In the course of their evolution, the angiosperms have radiated into most known plant forms and life histories. Their adaptation to a recently created habitat, the crop field, produced a novel form: the plant that allocates an unprecedented 30–60% of its net productivity to sexual structures. Long-lived trees, shrubs and vines of this form evolved, as did annual herbs. Perennial herb forms with increased allocation to asexual reproduction evolved, but there are no examples of perennial herbs with high sexual effort. We suggest that sowing seed into annually tilled fields favored shorter-lived herbs because of trade-offs between first-year seed production and relative growth rate and/or persistence. By propagating cuttings, people quickly domesticated tuber crops and large woody plants. Perennial herbs were too small to be efficiently propagated by cuttings, and the association between longevity, allogamy and genetic load made rapid domestication by sexual cycles unlikely. Perennial grain crops do not exist because they could not have evolved under the original set of conditions; however, they can be deliberately developed today through artificial phenotypic and genotypic selection. PMID:25567937

A simple method for maintaining relative positions of separate tissue elements during processing for electron microscopy.

PubMed

Stirling, C A

1978-09-01

Molten (328 K) 20% gelatin is used as a 'glue' to hold together separate tissue elements or tissue elements that may be separated when cutting small blocks of tissue for plastic embedding. Standard aldehyde and osmium fixation, dehydration and epoxy embedding are compatible with this as is semi-thin sectioning for light microscopy or thin sectioning for electron microscopy.

Real time computer controlled weld skate

NASA Technical Reports Server (NTRS)

Wall, W. A., Jr.

1977-01-01

A real time, adaptive control, automatic welding system was developed. This system utilizes the general case geometrical relationships between a weldment and a weld skate to precisely maintain constant weld speed and torch angle along a contoured workplace. The system is compatible with the gas tungsten arc weld process or can be adapted to other weld processes. Heli-arc cutting and machine tool routing operations are possible applications.

Transition and separation process in brine channels formation

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

Berti, Alessia, E-mail: alessia.berti@unibs.it; Bochicchio, Ivana, E-mail: ibochicchio@unisa.it; Fabrizio, Mauro, E-mail: mauro.fabrizio@unibo.it

2016-02-15

In this paper, we discuss the formation of brine channels in sea ice. The model includes a time-dependent Ginzburg-Landau equation for the solid-liquid phase change, a diffusion equation of the Cahn-Hilliard kind for the solute dynamics, and the heat equation for the temperature change. The macroscopic motion of the fluid is also considered, so the resulting differential system couples with the Navier-Stokes equation. The compatibility of this system with the thermodynamic laws and a maximum theorem is proved.

Performance analysis of microcomputer based differential protection of UHV lines under selective phase switching

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

Bhatti, A.A.

1990-04-01

This paper examines the effects of primary and secondary fault quantities as well s of mutual couplings of neighboring circuits on the sensitivity of operation and threshold settings of a microcomputer based differential protection of UHV lines under selective phase switching. Microcomputer based selective phase switching allows the disconnection of minimum number of phases involved in a fault and requires the autoreclosing of these phases immediately after the extinction of secondary arc. During a primary fault a heavy current contribution to the healthy phases tends to cause an unwanted tripping. Faulty phases physically disconnected constitute an isolated fault which beingmore » coupled to the system affects the current and voltage levels of the healthy phases still retained in the system and may cause an unwanted tripping. The microcomputer based differential protection, appears to have poor performance when applied to uncompensated lines employing selective pole switching.« less

Four-probe measurements with a three-probe scanning tunneling microscope

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

Salomons, Mark; Martins, Bruno V. C.; Zikovsky, Janik

2014-04-15

We present an ultrahigh vacuum (UHV) three-probe scanning tunneling microscope in which each probe is capable of atomic resolution. A UHV JEOL scanning electron microscope aids in the placement of the probes on the sample. The machine also has a field ion microscope to clean, atomically image, and shape the probe tips. The machine uses bare conductive samples and tips with a homebuilt set of pliers for heating and loading. Automated feedback controlled tip-surface contacts allow for electrical stability and reproducibility while also greatly reducing tip and surface damage due to contact formation. The ability to register inter-tip position bymore » imaging of a single surface feature by multiple tips is demonstrated. Four-probe material characterization is achieved by deploying two tips as fixed current probes and the third tip as a movable voltage probe.« less

High pressure reaction cell and transfer mechanism for ultrahigh vacuum spectroscopic chambers

NASA Astrophysics Data System (ADS)

Nelson, A. E.; Schulz, K. H.

2000-06-01

A novel high pressure reaction cell and sample transfer mechanism for ultrahigh vacuum (UHV) spectroscopic chambers is described. The design employs a unique modification of a commercial load-lock transfer system to emulate a tractable microreactor. The reaction cell has an operating pressure range of <1×10-4 to 1000 Torr and can be evacuated to UHV conditions to enable sample transfer into the spectroscopic chamber. Additionally, a newly designed sample holder equipped with electrical and thermocouple contacts is described. The sample holder is capable of resistive specimen heating to 400 and 800 °C with current requirements of 14 A (2 V) and 25 A (3.5 V), respectively. The design enables thorough material science characterization of catalytic reactions and the surface chemistry of catalytic materials without exposing the specimen to atmospheric contaminants. The system is constructed primarily from readily available commercial equipment allowing its rapid implementation into existing laboratories.

Portable ultrahigh-vacuum sample storage system for polarization-dependent total-reflection fluorescence x-ray absorption fine structure spectroscopy

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

Watanabe, Yoshihide, E-mail: e0827@mosk.tytlabs.co.jp; Nishimura, Yusaku F.; Suzuki, Ryo

A portable ultrahigh-vacuum sample storage system was designed and built to investigate the detailed geometric structures of mass-selected metal clusters on oxide substrates by polarization-dependent total-reflection fluorescence x-ray absorption fine structure spectroscopy (PTRF-XAFS). This ultrahigh-vacuum (UHV) sample storage system provides the handover of samples between two different sample manipulating systems. The sample storage system is adaptable for public transportation, facilitating experiments using air-sensitive samples in synchrotron radiation or other quantum beam facilities. The samples were transferred by the developed portable UHV transfer system via a public transportation at a distance over 400 km. The performance of the transfer system was demonstratedmore » by a successful PTRF-XAFS study of Pt{sub 4} clusters deposited on a TiO{sub 2}(110) surface.« less

Design of an Operando Positron Annihilation Gamma Spectrometer (OPAGS)

NASA Astrophysics Data System (ADS)

Satyal, S.; Joglekar, P.; Kalaskar, S.; Shastry, K.; Weiss, A. H.

2010-03-01

Surface properties measured under UHV conditions cannot be extended to surfaces interacting with gases under realistic pressures due to surface reconstruction and other strong perturbations of the surface. We present the design of an Operando Positron Annihilation Gamma Spectrometer (OPAGS) currently under construction at the University of Texas at Arlington. This new system will enable us to probe the surface and gather defect specific chemical and charge state information from surfaces under realistic pressures. Differential pumping will be used to maintain the sample in a gas environment while the rest of the beam is maintained under UHV. The Elemental content of the surface interacting with the gas environment will be determined from the Doppler broadened gamma spectra. This system will include a time of flight (TOF) positron annihilation induced Auger spectrometer (TOF-PAES) which correlates with the Doppler measurements at lower pressures. These new technique help to understand the charge transfer mechanisms at the surface.

Role of thermal processes in dewetting of epitaxial Ag(111) film on Si(111)

DOE PAGES

Sanders, Charlotte E.; Zhang, Chendong D.; Kellogg, Gary L.; ...

2014-08-01

Epitaxially grown silver (Ag) film on silicon (Si) is an optimal plasmonic device platform, but its technological utility has been limited by its tendency to dewet rapidly under ambient conditions (standard temperature and pressure). The mechanisms driving this dewetting have not heretofore been determined. In our study, scanning probe microscopy and low-energy electron microscopy are used to compare the morphological evolution of epitaxial Ag(111)/Si(111) under ambient conditions with that of similarly prepared films heated under ultra-high vacuum (UHV) conditions. Furthermore, dewetting is seen to be initiated with the formation of pinholes, which might function to relieve strain in the film.more » We find that in the UHV environment, dewetting is determined by thermal processes, and while under ambient conditions, thermal processes are not required. Finally, we conclude that dewetting in ambient conditions is triggered by some chemical process, most likely oxidation.« less

Constitutional Dynamics of Metal-Organic Motifs on a Au(111) Surface.

PubMed

Kong, Huihui; Zhang, Chi; Xie, Lei; Wang, Likun; Xu, Wei

2016-06-13

Constitutional dynamic chemistry (CDC), including both dynamic covalent chemistry and dynamic noncovalent chemistry, relies on reversible formation and breakage of bonds to achieve continuous changes in constitution by reorganization of components. In this regard, CDC is considered to be an efficient and appealing strategy for selective fabrication of surface nanostructures by virtue of dynamic diversity. Although constitutional dynamics of monolayered structures has been recently demonstrated at liquid/solid interfaces, most of molecular reorganization/reaction processes were thought to be irreversible under ultrahigh vacuum (UHV) conditions where CDC is therefore a challenge to be achieved. Here, we have successfully constructed a system that presents constitutional dynamics on a solid surface based on dynamic coordination chemistry, in which selective formation of metal-organic motifs is achieved under UHV conditions. The key to making this reversible switching successful is the molecule-substrate interaction as revealed by DFT calculations. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influence of pre-annealing of printed silver electrodes on ultrafast laser ablation of short thin-film transistor channels on flexible substrates

NASA Astrophysics Data System (ADS)

Wiig, M. S.; You, C. C.; Brox-Nilsen, C.; Foss, S. E.

2018-02-01

The cutoff frequency and current from an organic thin-film transistor (OTFT) are strongly dependent on the length and to some extent on the uniformity of the transistor channel. Reducing the channel length can improve the OTFT performance with the increase in the current and frequency. Picosecond laser ablation of the printed Ag electrodes, compatible with roll-to-roll fabrication, has been investigated. The ablation threshold was found to be similar for the laser wavelengths tested: 515 nm and 1030 nm. Short transistor channels could be opened both after light annealing at 70 °C and after annealing at 140 °C. The channels in the lightly cured films had a significantly less scale formation, which is critical for avoiding shunts in the device. By moving from bottom electrodes fully defined by printing to the bottom electrodes where the transistor channel is opened by the laser, the channel length could be reduced from 40 μm to less than 5 μm.

Artificial muscles of dielectric elastomers attached to artificial tendons of functionalized carbon fibers

NASA Astrophysics Data System (ADS)

Ye, Zhihang; Faisal, Md. Shahnewaz Sabit; Asmatulu, Ramazan; Chen, Zheng

2014-03-01

Dielectric elastomers are soft actuation materials with promising applications in robotics and biomedical de- vices. In this paper, a bio-inspired artificial muscle actuator with artificial tendons is developed for robotic arm applications. The actuator uses dielectric elastomer as artificial muscle and functionalized carbon fibers as artificial tendons. A VHB 4910 tape is used as the dielectric elastomer and PDMS is used as the bonding material to mechanically connect the carbon fibers to the elastomer. Carbon fibers are highly popular for their high electrical conductivities, mechanical strengths, and bio-compatibilities. After the acid treatments for the functionalization of carbon fibers (500 nm - 10 μm), one end of carbon fibers is spread into the PDMS material, which provides enough bonding strength with other dielectric elastomers, while the other end is connected to a DC power supply. To characterize the actuation capability of the dielectric elastomer and electrical conductivity of carbon fibers, a diaphragm actuator is fabricated, where the carbon fibers are connected to the actuator. To test the mechanical bonding between PDMS and carbon fibers, specimens of PDMS bonded with carbon fibers are fabricated. Experiments have been conducted to verify the actuation capability of the dielectric elastomer and mechanical bonding of PDMS with carbon fibers. The energy efficiency of the dielectric elastomer increases as the load increases, which can reach above 50%. The mechanical bonding is strong enough for robotic arm applications.

Asparagine 175 of connexin32 is a critical residue for docking and forming functional heterotypic gap junction channels with connexin26.

PubMed

Nakagawa, So; Gong, Xiang-Qun; Maeda, Shoji; Dong, Yuhua; Misumi, Yuko; Tsukihara, Tomitake; Bai, Donglin

2011-06-03

The gap junction channel is formed by proper docking of two hemichannels. Depending on the connexin(s) in the hemichannels, homotypic and heterotypic gap junction channels can be formed. Previous studies suggest that the extracellular loop 2 (E2) is an important molecular domain for heterotypic compatibility. Based on the crystal structure of the Cx26 gap junction channel and homology models of heterotypic channels, we analyzed docking selectivity for several hemichannel pairs and found that the hydrogen bonds between E2 domains are conserved in a group of heterotypically compatible hemichannels, including Cx26 and Cx32 hemichannels. According to our model analysis, Cx32N175Y mutant destroys three hydrogen bonds in the E2-E2 interactions due to steric hindrance at the heterotypic docking interface, which makes it unlikely to dock with the Cx26 hemichannel properly. Our experimental data showed that Cx26-red fluorescent protein (RFP) and Cx32-GFP were able to traffic to cell-cell interfaces forming gap junction plaques and functional channels in transfected HeLa/N2A cells. However, Cx32N175Y-GFP exhibited mostly intracellular distribution and was occasionally observed in cell-cell junctions. Double patch clamp analysis demonstrated that Cx32N175Y did not form functional homotypic channels, and dye uptake assay indicated that Cx32N175Y could form hemichannels on the cell surface similar to wild-type Cx32. When Cx32N175Y-GFP- and Cx26-RFP-transfected cells were co-cultured, no colocalization was found at the cell-cell junctions between Cx32N175Y-GFP- and Cx26-RFP-expressing cells; also, no functional Cx32N175Y-GFP/Cx26-RFP heterotypic channels were identified. Both our modeling and experimental data suggest that Asn(175) of Cx32 is a critical residue for heterotypic docking and functional gap junction channel formation between the Cx32 and Cx26 hemichannels.

Mars: A water-rich planet?

USGS Publications Warehouse

Carr, M.H.

1986-01-01

Mars had outgassed at least 0.5 to 1 km of water, 10 to 20 bar of CO2, and 0.1 to 0.3 bar of N2. The volatiles that have been retained are mostly in the cratered uplands. Terrain softening, fretted channels, debris flows, and closed depressions indicate that at least the upper 2 km of the cratered uplands at high latitudes (>30??) contain ice in amounts that exceed the porosity, estimated to be 10-20%. Theoretical studies, and lack of these features in the cratered uplands at low latitudes, suggest that the upper 1 km of the uplands at low latitudes is ice poor. However, valley networks indicate that water was present near the surface early in the planet's history, although in amounts smaller than at high latitudes. The entire upper 1 km, planetwide is estimated to have contained 75-125 m of water at the end of heavy bombardment. The largest sink for water is the megaregolith below 1 km. Episodic eruption of water from the deep megaregolith cut many of the large outflow channels. From the volume of water needed to cut the circum-Chryse channels, and assuming uniform planetwide distribution of water, the deep megaregolith is estimated to have contained at least 350 m of water at the end of heavy bombardment, thereby giving a total minimum inventory of 424-475 m planetwide. Most of the water lost from the low-latitude uplands by diffusion and in cutting the valley networks is now believed to be in the polar layered terrains. Most of the water involved in cutting the outflow channels is in the low-lying northern plains where a variety of features that have been attributed to ground ice is present. A large fraction of the planet's surface has been overplated with water-poor volcanics, of which we have samples in the SNC meteorites. The younger volcanics have reacted extensively with the old volatile-rich basement. Some of the CO2 and N2 outgassed was lost during heavy bombardment by impact erosion of the atmosphere and other processes. The remaining was fixed carbonates and folded deep into the megaregolith during heavy bombardment. ?? 1986.

New Holocene Slip-rate Sites Along the Mojave San Andreas Fault Near Palmdale, CA

NASA Astrophysics Data System (ADS)

Young, E. K.; Cowgill, E.; Scharer, K. M.

2016-12-01

The slip rate for the Mojave San Andreas fault (MSAF) is poorly known: the long-term ( 413ky) geologic rate is as high as 37mm/yr [1] while the geodetic slip rate is as low as 15mm/yr [2]. To determine the Holocene-average rate for the MSAF, we investigated several offset landforms near Palmdale, CA using detailed surficial mapping and 14C analyses of charcoal collected from hand-dug excavations. Site X-12 preserves two offset markers sourced from a north-flowing catchment south of the fault. One is a terrace riser cut into older alluvium that is abutted by the eastern margin of a Qf3 fan and is displaced by 75 m. Offset of the riser and the alluvium generated a north-facing fault-scarp that was eroded to form a small fan on top of the eastern margin of the Qf3 fan. The second offset is a beheaded channel that is incised into the Qf3 fan north of the fault and is displaced 50m, and thus formed after the riser was offset by 25m. To date these landforms we opened 5 excavations at the site, with emphasis on the beheaded channel. Dates from within the Qf3 fan south/upstream of the fault and abandoned bedload in the beheaded channel give maximum and minimum ages for the channel incision of 1500calBP and 600calBP, respectively, implying a rate ≥33mm/yr. Future work seeks to date post-abandonment channel-fill deposits and the upper and lower bounds on the terrace riser. At a second site, Ranch Center, a north-flowing stream cut across a shutter ridge north of the fault and was then offset and deflected 80m before cutting a new channel across the fault. Future work here seeks to date the bases of the alluvial fans deposited by the abandoned and active channels to obtain maximum and minimum ages for the 80 m offset, respectively. Rates from these sites should help to better define the Holocene slip rate on the MSAF. 1) Matmon et al., 2005, GSAB. v. 117 p. 795 2) Becker et al., 2005, Geoph.. J. Int., v. 160 p. 634

A Fully Integrated Wireless Compressed Sensing Neural Signal Acquisition System for Chronic Recording and Brain Machine Interface.

PubMed

Liu, Xilin; Zhang, Milin; Xiong, Tao; Richardson, Andrew G; Lucas, Timothy H; Chin, Peter S; Etienne-Cummings, Ralph; Tran, Trac D; Van der Spiegel, Jan

2016-07-18

Reliable, multi-channel neural recording is critical to the neuroscience research and clinical treatment. However, most hardware development of fully integrated, multi-channel wireless neural recorders to-date, is still in the proof-of-concept stage. To be ready for practical use, the trade-offs between performance, power consumption, device size, robustness, and compatibility need to be carefully taken into account. This paper presents an optimized wireless compressed sensing neural signal recording system. The system takes advantages of both custom integrated circuits and universal compatible wireless solutions. The proposed system includes an implantable wireless system-on-chip (SoC) and an external wireless relay. The SoC integrates 16-channel low-noise neural amplifiers, programmable filters and gain stages, a SAR ADC, a real-time compressed sensing module, and a near field wireless power and data transmission link. The external relay integrates a 32 bit low-power microcontroller with Bluetooth 4.0 wireless module, a programming interface, and an inductive charging unit. The SoC achieves high signal recording quality with minimized power consumption, while reducing the risk of infection from through-skin connectors. The external relay maximizes the compatibility and programmability. The proposed compressed sensing module is highly configurable, featuring a SNDR of 9.78 dB with a compression ratio of 8×. The SoC has been fabricated in a 180 nm standard CMOS technology, occupying 2.1 mm × 0.6 mm silicon area. A pre-implantable system has been assembled to demonstrate the proposed paradigm. The developed system has been successfully used for long-term wireless neural recording in freely behaving rhesus monkey.

A nanosecond pulsed laser heating system for studying liquid and supercooled liquid films in ultrahigh vacuum

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

Xu, Yuntao; Dibble, Collin J.; Petrik, Nikolay G.

2016-04-26

A pulsed laser heating system has been developed that enables investigations of the dynamics and kinetics of nanoscale liquid films and liquid/solid interfaces on the nanosecond timescale in ultrahigh vacuum (UHV). Details of the design, implementation and characterization of a nanosecond pulsed laser system for transiently heating nanoscale films are described. Nanosecond pulses from a Nd:YAG laser are used to rapidly heat thin films of adsorbed water or other volatile materials on a clean, well-characterized Pt(111) crystal in UHV. Heating rates of ~1010 K/s for temperature increases of ~100 – 200 K are obtained. Subsequent rapid cooling (~5 × 109more » K/s) quenches the film, permitting in-situ, post-mortem analysis using a variety of surface science techniques. Lateral variations in the laser pulse energy are ~ ± 3% leading to a temperature uncertainty of ~ ± 5 K for a temperature jump of 200 K. Initial experiments with the apparatus demonstrate that crystalline ice films initially held at 90 K can be rapidly transformed into liquid water films with T > 273 K. No discernable recrystallization occurs during the rapid cooling back to cryogenic temperatures. In contrast, amorphous solid water films heated below the melting point rapidly crystallize. The nanosecond pulsed laser heating system can prepare nanoscale liquid and supercooled liquid films that persist for nanoseconds per heat pulse in an UHV environment, enabling experimental studies of a wide range of phenomena in liquids and at liquid/solid interfaces.« less

Highly hydrogen-sensitive thermal desorption spectroscopy system for quantitative analysis of low hydrogen concentration (˜1 × 1016 atoms/cm3) in thin-film samples

NASA Astrophysics Data System (ADS)

Hanna, Taku; Hiramatsu, Hidenori; Sakaguchi, Isao; Hosono, Hideo

2017-05-01

We developed a highly hydrogen-sensitive thermal desorption spectroscopy (HHS-TDS) system to detect and quantitatively analyze low hydrogen concentrations in thin films. The system was connected to an in situ sample-transfer chamber system, manipulators, and an rf magnetron sputtering thin-film deposition chamber under an ultra-high-vacuum (UHV) atmosphere of ˜10-8 Pa. The following key requirements were proposed in developing the HHS-TDS: (i) a low hydrogen residual partial pressure, (ii) a low hydrogen exhaust velocity, and (iii) minimization of hydrogen thermal desorption except from the bulk region of the thin films. To satisfy these requirements, appropriate materials and components were selected, and the system was constructed to extract the maximum performance from each component. Consequently, ˜2000 times higher sensitivity to hydrogen than that of a commercially available UHV-TDS system was achieved using H+-implanted Si samples. Quantitative analysis of an amorphous oxide semiconductor InGaZnO4 thin film (1 cm × 1 cm × 1 μm thickness, hydrogen concentration of 4.5 × 1017 atoms/cm3) was demonstrated using the HHS-TDS system. This concentration level cannot be detected using UHV-TDS or secondary ion mass spectroscopy (SIMS) systems. The hydrogen detection limit of the HHS-TDS system was estimated to be ˜1 × 1016 atoms/cm3, which implies ˜2 orders of magnitude higher sensitivity than that of SIMS and resonance nuclear reaction systems (˜1018 atoms/cm3).

A nanosecond pulsed laser heating system for studying liquid and supercooled liquid films in ultrahigh vacuum.

PubMed

Xu, Yuntao; Dibble, Collin J; Petrik, Nikolay G; Smith, R Scott; Joly, Alan G; Tonkyn, Russell G; Kay, Bruce D; Kimmel, Greg A

2016-04-28

A pulsed laser heating system has been developed that enables investigations of the dynamics and kinetics of nanoscale liquid films and liquid/solid interfaces on the nanosecond time scale in ultrahigh vacuum (UHV). Details of the design, implementation, and characterization of a nanosecond pulsed laser system for transiently heating nanoscale films are described. Nanosecond pulses from a Nd:YAG laser are used to rapidly heat thin films of adsorbed water or other volatile materials on a clean, well-characterized Pt(111) crystal in UHV. Heating rates of ∼10(10) K/s for temperature increases of ∼100-200 K are obtained. Subsequent rapid cooling (∼5 × 10(9) K/s) quenches the film, permitting in-situ, post-heating analysis using a variety of surface science techniques. Lateral variations in the laser pulse energy are ∼±2.7% leading to a temperature uncertainty of ∼±4.4 K for a temperature jump of 200 K. Initial experiments with the apparatus demonstrate that crystalline ice films initially held at 90 K can be rapidly transformed into liquid water films with T > 273 K. No discernable recrystallization occurs during the rapid cooling back to cryogenic temperatures. In contrast, amorphous solid water films heated below the melting point rapidly crystallize. The nanosecond pulsed laser heating system can prepare nanoscale liquid and supercooled liquid films that persist for nanoseconds per heat pulse in an UHV environment, enabling experimental studies of a wide range of phenomena in liquids and at liquid/solid interfaces.

Flow discharge prediction in compound channels using linear genetic programming

NASA Astrophysics Data System (ADS)

Azamathulla, H. Md.; Zahiri, A.

2012-08-01

SummaryFlow discharge determination in rivers is one of the key elements in mathematical modelling in the design of river engineering projects. Because of the inundation of floodplains and sudden changes in river geometry, flow resistance equations are not applicable for compound channels. Therefore, many approaches have been developed for modification of flow discharge computations. Most of these methods have satisfactory results only in laboratory flumes. Due to the ability to model complex phenomena, the artificial intelligence methods have recently been employed for wide applications in various fields of water engineering. Linear genetic programming (LGP), a branch of artificial intelligence methods, is able to optimise the model structure and its components and to derive an explicit equation based on the variables of the phenomena. In this paper, a precise dimensionless equation has been derived for prediction of flood discharge using LGP. The proposed model was developed using published data compiled for stage-discharge data sets for 394 laboratories, and field of 30 compound channels. The results indicate that the LGP model has a better performance than the existing models.

Energy conditions of high quality laser-oxygen cutting of mild steel

NASA Astrophysics Data System (ADS)

Shulyatyev, V. B.; Orishich, A. M.; Malikov, A. G.

2011-02-01

In our previous work we found experimentally the scaling laws for the oxygen-assisted laser cutting of low-carbon steel of 5 - 25 mm. No dross and minimal roughness of the cut surface were chosen as criteria of quality. Formulas were obtained to determine the optimum values of the laser power and cutting speed for the given sheet thickness. In the present paper, the energy balance of the oxygen-assisted laser cutting is studied experimentally at these optimum parameters. The absorbed laser energy and heat conduction losses and cut width were measured experimentally, and then the energy of exothermic reaction of oxidation was found from the balance equation. To define the integral coefficient of absorption, the laser power was measured on the cutting channel exit during the cutting. The heat conduction losses were measured by the calorimetric method. It has been established that the absorbed laser energy, oxidation energy, thermal losses and melting enthalpy related to a sheet thickness unit, do not depend on the sheet thickness at the cutting with the minimal roughness. The results enable to determine the fraction of the oxidized iron in the melt and thermal efficiency at the cutting with the minimal roughness. The share of the oxidation reaction energy is 50 - 60% in the total contributed energy.

Nyquist-WDM filter shaping with a high-resolution colorless photonic spectral processor.

PubMed

Sinefeld, David; Ben-Ezra, Shalva; Marom, Dan M

2013-09-01

We employ a spatial-light-modulator-based colorless photonic spectral processor with a spectral addressability of 100 MHz along 100 GHz bandwidth, for multichannel, high-resolution reshaping of Gaussian channel response to square-like shape, compatible with Nyquist WDM requirements.

Forward and backward motion of artificial helical swimmers in cylindrical channels

NASA Astrophysics Data System (ADS)

Acemoglu, Alperen; Temel, Fatma Zeynep; Yesilyurt, Serhat

2013-11-01

Motion of micro swimmers in confined geometries such as channels is important due to its relevance in in vivo medical applications such as minimally invasive surgery and drug delivery. Here, swimmers with diameters 0.8 mm and lengths 2 to 3 mm are produced with a 3D printer and cylindrical Nd2Fe14B magnets are placed inside the bodies. Rotating external magnetic field is used for the actuation of artificial swimmers. Different body and tail geometries are produced and experiments are conducted with a glycerol filled circular channel. Result demonstrate that decreasing channel diameter directly affects the forward motion of the swimmer due to the increasing drag. It is observed that step-out frequency, which defines maximum frequency at which the swimmer can establish a synchronous rotation with the external magnetic field, depends on the geometry of the swimmer and the channel diameter. There are significant differences between low and high frequency motion and forward and backward swimming. Longer tails enable higher forward velocities in high frequencies than backward ones, whereas forward and backward velocities are approximately the same at low frequencies. Furthermore backward motion is more stable than the forward one; at high frequencies, swimmers travel almost at the center of the channel for backward motion, and follow a helical trajectory near the wall during the forward motion. According to simulation results there is a flow which is induced by the rotation of the swimmer rotation that affects the swimmer's trajectory. We acknowledge the support from TUBITAK (Techonological & Research Council of Turkey) under the grant no: 111M376.

The origin of the Dargom canal in the oasis of Samarkand (Uzbekistan). A new scenario from geoarcheological data

NASA Astrophysics Data System (ADS)

Marconi, V.; Mantellini, S.; Picotti, V.; Gabbianelli, G.; Tosi, M.

2009-04-01

As the main oases developed in the arid regions of Central Asia, the region of Samarkand is the outcome of large hydraulic works carried out since the past times. The main result of such a great landscape transformation is a complex irrigation network formed by several artificial channels and useful for both urban water supply and irrigation purposes. Within the framework of the Italo-Uzbek Archaeological Project begun in 2001, a specific study was aimed to reconstruct the history of Dargom, the primary canal on the South of the city, and its relationships with the settlement dynamics. According to the most accepted theories, the Dargom was dug during the Achaemenid Age (6th-4th c. BC) as a consequence of a master plan linked to a strong central political power. The new investigations carried out by a joined team of Archaelogists and Geologists from the University Bologna allowed a new hypothesis on the way of digging and the chronology of the Dargom itself. The analyses on the historical settlement patterns seem to suggest a low development of Samarkand's territory during the Achaemenid times, whilst the increasing of sites during the Early Middle Age (5th-8th c.) can be explained throughout the rich trades along the Silk Road as well as the development of irrigated agriculture. The present-day Dargom is a high sinuosity channel deeply incised into the bedrock flowing to the east, strongly resembling a natural channel. It has been excavated for around 70 km along an apron of alluvial fans sourced by a southern mountain range. Its morphology clearly document a natural evolution after excavation: incision and meandering took place, likely due to the increasing gradient related to the headward migration of lowering of the base-level and the decrease of the bed load through time. Field survey around the fortress of Kafir Kala, the main archeological site geographically linked to the Dargom, allowed reconstructing the original bed of the canal, marked by a layer of sand with different composition respect to the substrate. In several places, the artificial cut in the most elevated (left) bank of the canal was recognized, interrupted by depression of the banks associated with crevasse deposits reaching several tens of meters uphill. In the less elevated bank (right) of the canal, the original artificial levee was never observed. It is worth mentioning an important reworking of the landscape due to the land reform of the Soviet administration in the years '60 of the last century. A trench cut across the left side of the canal, showed a clinostratified body of sand covering the sand deposits of the ancient Dargom. The composition is local and it bears fragments of bricks and bones, to be interpreted as waste material shed from the top to protect the bank. Radiocarbon ages of two bones each separated 60 cm, are 1700 ±30 and 1680 ±120 BP. A DEM was created based on a 1:10.000 scale topo map preceding the land reform, to document, thanks to a high detail of the contour lines (1 m), the micromorphological features associated to the canal. The resulting TIN was processed through the ESRI hydrology modeling functions, and the flow accumulation rate in the study area was calculated with the grid of 1 m. A slightly discontinuous ridge, with only a few meters of elevation from the surroundings, was identified on the right bank of the canal. Several cross sections document that this ridge correspond to the original levee and it is located 100 to 400 m north of the present-day incised bank. Therefore, the original profile of the canal was reconstructed, much larger than expected and interspersed with artificial mounds, previously thought outside the canal, whose function has to be reconsidered. The new geo-archaeological resercheas allowed a new interpretation on the history of Dargom. According to it the canal should be dated back to the Early Middle Age and its morphology can be reconstructed but other consideration can be advanced in relation to the labour investments required to realize such a great hydraulic work. Thus, in our opinion the Dargom is not an imposition by a central power authority but the result of the common effort carried out by cities and villages around Samarkand in order to supply more water for the agricultural development of the region.

Goddard Space Flight Center specification for Helical-Scan 8-millimeter (mm) magnetic digital data tape cartridge

NASA Technical Reports Server (NTRS)

Perry, Jimmy L.

1992-01-01

The same kind of standard and controls are established that are currently in use for the procurement of new analog, digital, and IBM/IBM compatible 3480 tape cartridges, and 1 in wide channel video magnetic tapes. The Magnetic Tape Certification Facility (MTCF) maintains a Qualified Products List (QPL) for the procurement of new magnetic media and uses the following specifications for the QPL and Acceptance Tests: (1) NASA TM-79724 is used for the QPL and Acceptance Testing of new analog magnetic tapes; (2) NASA TM-80599 is used for the QPL and Acceptance Testing of new digital magnetic tapes; (3) NASA TM-100702 is used for the QPL and Acceptance Testing of new IBM/IBM compatible 3840 magnetic tape cartridges; and (4) NASA TM-100712 is used for the QPL and Acceptance Testing of new 1 in wide channel video magnetic tapes. This document will be used for the QPL and Acceptance Testing of new Helical Scan 8 mm digital data tape cartridges.

Persistence of historical logging impacts on channel form in mainstem North Fork Caspar Creek

Treesearch

Michael B. Napolitano

1998-01-01

The old-growth redwood forest of North Fork Caspar Creek was clear-cut logged between 1860 and 1904. Transportation of logs involved construction of a splash dam in the headwaters of North Fork Caspar Creek. Water stored behind the dam was released during large storms to enable log drives. Before log drives could be conducted, the stream channel had to be prepared by...

Electrical Measurements and Nanomechanics Using Scanning Probe Microscopy

NASA Astrophysics Data System (ADS)

Chang, Yong

2002-10-01

In the early 1980s, G. Binnig et al. invented the Scanning Tunneling Microscopy (STM) [1], making it possible to obtain atomic resolution images of conducting surfaces. After that, many different types of Scanning Probe Microscopy (SPM) were invented and some of the most useful representatives are Atomic Force Microscopy (AFM) [2], Electrostatic Force Microscopy (EFM) [3] and Kelvin Probe Force Microscopy (KPFM) [4,5]. In 1985, G. Binnig et al. [2] invented the AFM, which now is used as a fundamental tool in many fields of research. Developed from AFM, Y. Martin et al. [3] invented EFM in 1987. The development of AC mode AFM allows the detection of weak long-range forces. EFM has also been used to study other systems and phenomena, such as thin liquid films on solid surfaces [6], electrically stressed gold nanowires [7], and spatial charge distribution in quantum wires [8]. In 1991, M. Nonnenmacher et al. [5] invented Kelvin Probe Force Microscopy. KPFM is used to study any property that affects the tip-surface Contact Potential Difference (CPD), such as voltage signals in integrated circuits (IC) [9], charged grain boundaries in polycrystalline silicon [10] and surface potential variations in multilayer semiconductor devices [11]. The aim of this poster is to discuss the application of SPM to electrical measurements. The theory of SPM was presented. The AFM was firstly introduced as it was developed before the other two. The design and theory were discussed. The force-distance curve was introduced. After this EFM was presented. EFM was developed from AC mode AFM. The technique was achieved by applying a DC voltage between the tip and the sample. The design, theory and features of it were surveyed. KPFM was also discussed. KPFM was developed from EFM. The central part of this technique is to measure the CPD. Experimental measurements of SPM were described after theory part. Research work using AFM was presented. The newest technique of AFM, UHV-AFM has been used in investigating the nano-mechanical properties of different materials. Normally common AFM has shortcomings as it has either strict limit resolution or difficulties in interpreting the data from the measurements. In order to solve these problems, Ultra High Vacuum (UHV) conditions were applied to acquire quantitative results. A typical UHV-AFM uses a cantilever whose spring constant is relatively high (>100 N/m) to obtain high-resolution image. Experimental measurements using KPFM was presented after AFM. Researchers are using KPFM to acquire the topography and measuring the CPD of semiconductor or metal surfaces. Similarly as in AFM, KPFM works best in UHV environment. A typical UHV-KPFM also uses a cantilever whose spring constant is relatively high. A UHV-KPFM may be able to achieve a high resolution in CPD images. In the past 20 years many different kinds of SPM were invented and used. AFM, EFM, and KPFM are representatives of them. Researchers are still developing new techniques. However, in recent years, they pay more attention in improving the measurement accuracy instead of trying to invent new SPM. These three SPM continue to be frequently used. The current capabilities of SPM do not satisfy us completely. We still cant measure the Electrical field directly. We actually measure the capacitance gradient. There are also some other questions. This is because the electrostatic force depends very strongly on the geometry of the probe at all length scales, so any model is subject to two big problems. First, the geometry is not known with complete accuracy; and second, the tip shape can change during an experiment due to wear. In the future, maybe the problems could be overcome by using a tip with a very well defined shape, such as a carbon nanotube, for which a realistic geometrical model could be more easily constructed, and the wear could be avoided or reduced.

Grumman WS33 wind system: prototype construction and testing, Phase II technical report

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

Adler, F.M.; Henton, P.; King, P.W.

1980-11-01

The prototype fabrication and testing of the 8 kW small wind energy conversion system are reported. The turbine is a three-bladed, down-wind machine designed to interface directly with an electrical utility network. The machine as finally fabricated is rated at 15 kW at 24 mpH and peak power of 18 kW at 35 mph. Utility compatible electrical power is generated in winds between a cut-in speed of 9 mph and a cut-out speed of 35 mph by using the torque characteristics of the unit's induction generator combined with the rotor aerodynamics to maintain essentially constant speed. Inspection procedures, pre-delivery testing,more » and a cost analysis are included.« less

Estimation of the laser cutting operating cost by support vector regression methodology

NASA Astrophysics Data System (ADS)

Jović, Srđan; Radović, Aleksandar; Šarkoćević, Živče; Petković, Dalibor; Alizamir, Meysam

2016-09-01

Laser cutting is a popular manufacturing process utilized to cut various types of materials economically. The operating cost is affected by laser power, cutting speed, assist gas pressure, nozzle diameter and focus point position as well as the workpiece material. In this article, the process factors investigated were: laser power, cutting speed, air pressure and focal point position. The aim of this work is to relate the operating cost to the process parameters mentioned above. CO2 laser cutting of stainless steel of medical grade AISI316L has been investigated. The main goal was to analyze the operating cost through the laser power, cutting speed, air pressure, focal point position and material thickness. Since the laser operating cost is a complex, non-linear task, soft computing optimization algorithms can be used. Intelligent soft computing scheme support vector regression (SVR) was implemented. The performance of the proposed estimator was confirmed with the simulation results. The SVR results are then compared with artificial neural network and genetic programing. According to the results, a greater improvement in estimation accuracy can be achieved through the SVR compared to other soft computing methodologies. The new optimization methods benefit from the soft computing capabilities of global optimization and multiobjective optimization rather than choosing a starting point by trial and error and combining multiple criteria into a single criterion.

Electrolyte Chemistry for Simultaneous Stabilization of Potassium Metal and Superoxide in K-O₂ Batteries.

PubMed

Xiao, Neng; Gourdin, Gerald; Wu, Yiying

2018-05-22

In the superoxide batteries based on O2/O2- redox chemistry, identifying an electrolyte to stabilize both alkali metal and superoxide remains challenging due to their reactivity towards electrolyte components. Bis(fluorosulfonyl)imide (FSI-) has been recognized as a "magical anion" for passivating alkali metals. Herein, we illustrate the chemical reactions between FSI- and superoxide, and the resultant dilemma when considering an anode-compatible electrolyte vs. a cathode-compatible one in K-O2 batteries. On one side, the KFSI-dimethoxyethane (DME) electrolyte passivates the potassium metal anode via the cleavage of S-F bond and formation of a KF-rich solid electrolyte interface (SEI). Nevertheless, the KFSI salt is chemically unstable due to the nucleophilic attack by superoxide and/or hydroxide species. On the other hand, potassium bis(trifluorosulfonyl)imide (KTFSI) is stable for KO2, but results in mossy deposition and irreversible plating and stripping. In order to circumvent this dilemma, we develop an artificial SEI for K metal anode to achieve long cycle-life K-O2 batteries. This work contributes to the understanding of electrolyte chemistry and guides the development of stable electrolytes and artificial SEI in metal-O2 batteries. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A comparison RSM and ANN surface roughness models in thin-wall machining of Ti6Al4V using vegetable oils under MQL-condition

NASA Astrophysics Data System (ADS)

Mohruni, Amrifan Saladin; Yanis, Muhammad; Sharif, Safian; Yani, Irsyadi; Yuliwati, Erna; Ismail, Ahmad Fauzi; Shayfull, Zamree

2017-09-01

Thin-wall components as usually applied in the structural parts of aeronautical industry require significant challenges in machining. Unacceptable surface roughness can occur during machining of thin-wall. Titanium product such Ti6Al4V is mostly applied to get the appropriate surface texture in thin wall designed requirements. In this study, the comparison of the accuracy between Response Surface Methodology (RSM) and Artificial Neural Networks (ANN) in the prediction of surface roughness was conducted. Furthermore, the machining tests were carried out under Minimum Quantity Lubrication (MQL) using AlCrN-coated carbide tools. The use of Coconut oil as cutting fluids was also chosen in order to evaluate its performance when involved in end milling. This selection of cutting fluids is based on the better performance of oxidative stability than that of other vegetable based cutting fluids. The cutting speed, feed rate, radial and axial depth of cut were used as independent variables, while surface roughness is evaluated as the dependent variable or output. The results showed that the feed rate is the most significant factors in increasing the surface roughness value followed by the radial depth of cut and lastly the axial depth of cut. In contrary, the surface becomes smoother with increasing the cutting speed. From a comparison of both methods, the ANN model delivered a better accuracy than the RSM model.

Joint Symposium on Compatibility of Plastics/Materials with Explosives Processing Explosives Held in Albuquerque, New Mexico on 15-17 May 1979.

DTIC Science & Technology

1979-05-01

250 A. S. Tompa REAL-TIME LOW TEMPERATURE NC AND PBX 9404 DECOMPOSITION STUDIES ....................................... 276 ._- Dr. Hermann...the five major unit operations for multi-base cannon propellant; nitrocellulose dehydration , premixing, mixing, extruding and cutting. Throughout the...during facility design, a general process description is presented as follows: Thermal Dehydration Nitrocellulose (NC) slurry is fed to a continuous

Influence of herbicides and improvement cutting, fertilization, and prescribed fire on planted longleaf pine development

Treesearch

James D. Haywood

2015-01-01

There is an interest in restoring longleaf pine (Pinus palustris Mill.) across its native range in the southeastern United States, and establishment of longleaf pine on much of its original range requires artificial regeneration and management of competing vegetation after planting. In Louisiana, two fertilization levels (No or Yes [36 kg/ha...

Predicting stocking improvement in reproduction stands of Douglas-fir.

Treesearch

George R. Staebler

1948-01-01

Some cut or burned-over Douglas-fir areas restocked promptly and fully. Others do not and seemingly never will restock adequately without the help of artificial seeding or planting. On some areas widely scattered seedlings become established and grow; filling-in is by second generation trees from the seed of these scattered parents. On still other areas stocking...

Frequency weighting for vibration-induced white finger compatible with exposure-response models.

PubMed

Brammer, Anthony J; Pitts, Paul M

2012-01-01

An analysis has been performed to derive a frequency weighting for the development of vibration-induced white finger (VWF). It employs a model to compare health risks for pairs of population groups that are selected to have similar health outcomes from operating power tools or machines with markedly different acceleration spectra (rock drills, chain saws, pavement breakers and motorcycles). The model defines the Relative Risk, RR(f(trial)), which is constructed from the ratio of daily exposures and includes a trial frequency weighting that is applied to the acceleration spectra. The trial frequency weighting consists of a frequency-independent primary frequency range, and subordinate frequency ranges in which the response to vibration diminishes, with cut-off frequencies that are changed to influence the magnitude of RR(f(trial)). The frequency weighting so derived when RR(f(trial)) = 1 is similar to those obtained by other methods (W(hf), W(hT)). It consists of a frequency independent range from about 25 Hz to 500 Hz (-3 dB frequencies), with an amplitude cut-off rate of 12 dB/octave below 25 Hz and above 500 Hz. The range is compatible with studies of vasoconstriction in persons with VWF. The results provide further evidence that the ISO frequency weighting may be inappropriate for assessing the risk of developing VWF.

The Seasonal Dynamics of Artificial Nest Predation Rates along Edges in a Mosaic Managed Reedbed.

PubMed

Malzer, Iain; Helm, Barbara

2015-01-01

Boundaries between different habitats can be responsible for changes in species interactions, including modified rates of encounter between predators and prey. Such 'edge effects' have been reported in nesting birds, where nest predation rates can be increased at habitat edges. The literature concerning edge effects on nest predation rates reveals a wide variation in results, even within single habitats, suggesting edge effects are not fixed, but dynamic throughout space and time. This study demonstrates the importance of considering dynamic mechanisms underlying edge effects and their relevance when undertaking habitat management. In reedbed habitats, management in the form of mosaic winter reed cutting can create extensive edges which change rapidly with reed regrowth during spring. We investigate the seasonal dynamics of reedbed edges using an artificial nest experiment based on the breeding biology of a reedbed specialist. We first demonstrate that nest predation decreases with increasing distance from the edge of cut reed blocks, suggesting edge effects have a pivotal role in this system. Using repeats throughout the breeding season we then confirm that nest predation rates are temporally dynamic and decline with the regrowth of reed. However, effects of edges on nest predation were consistent throughout the season. These results are of practical importance when considering appropriate habitat management, suggesting that reed cutting may heighten nest predation, especially before new growth matures. They also contribute directly to an overall understanding of the dynamic processes underlying edge effects and their potential role as drivers of time-dependent habitat use.

An experimental setup to characterize MR switched gradient-induced potentials.

PubMed

Fokapu, Odette; El-Tatar, Aziz

2013-06-01

We have developed an experimental setup as an in vitro research tool for studying the contamination of electrophysiological signals (EPS) by MRI environment; particularly, when due to the switched gradient-induced potentials. The system is composed of: 1) a MRI compatible module for the transmission of the EPS into the MRI tunnel, 2) a gelatin-based tissue-mimicking phantom, placed inside the tunnel, in which EPS is injected, 3) a detection module composed of a five input channel MRI compatible transmitter placed inside the tunnel, allowing an on-site pre-amplification of the bio-potentials and their transmission, via an optical fiber cable, to a four filtered output per channel receiver (350 Hz, 160 Hz, 80 Hz, and 40 Hz, for a total of 20 channels) placed in the control room, and 4) a signal processing algorithm used to analyze the generated induced potentials. A set of tests were performed to validate the electronic performances of the setup. We also present in this work an interesting application of the setup, i.e., the acquisition and analysis of the induced potentials with respect of the slice orientation for a given MRI sequence. Significant modifications of the time and frequency characteristics were observed with respect to axial, coronal or sagittal orientations.

Telerobotic-assisted bone-drilling system using bilateral control with feed operation scaling and cutting force scaling

PubMed Central

Kasahara, Yusuke; Kawana, Hiromasa; Usuda, Shin; Ohnishi, Kouhei

2012-01-01

Background Drilling is used in the medical field, especially in oral surgery and orthopaedics. In recent years, oral surgery involving dental implants has become more common. However, the risky drilling process causes serious accidents. To prevent these accidents, supporting systems such as robotic drilling systems are required. Methods A telerobotic-assisted drilling system is proposed. An acceleration-based four-channel bilateral control system is implemented in linear actuators in a master–slave system for drill feeding. A reaction force observer is used instead of a force sensor for measuring cutting force. Cutting force transmits from a cutting material to a surgeon, who may feel a static cutting resistance force and vigorous cutting vibrations, via the master–slave system. Moreover, position scaling and force scaling are achieved. Scaling functions are used to achieve precise drilling and hazard detection via force sensation. Results Cutting accuracy and reproducibility of the cutting force were evaluated by angular velocity/position error and frequency analysis of the cutting force, respectively, and errors were > 2.0 rpm and > 0.2 mm, respectively. Spectrum peaks of the cutting vibration were at the theoretical vibration frequencies of 30, 60 and 90 Hz. Conclusions The proposed telerobotic-assisted drilling system achieved precise manipulation of the drill feed and vivid feedback from the cutting force. Copyright © 2012 John Wiley & Sons, Ltd. PMID:22271710

Installation of an artificial vegetating island in oligomesotrophic Lake Paro, Korea.

PubMed

Seo, Eun-Young; Kwon, Oh-Byung; Choi, Seung-Ik; Kim, Ji-Ho; Ahn, Tae-Seok

2013-01-01

After cut off of inflowing water, Lake Paro, an oligomesotrophic lake lost littoral zone, an important region for the aquatic ecosystem. For the first step of restoration, the artificial vegetation island was installed. The concentration of nutrients in lake water was not sufficient for the growth of macrophyte as total phosphate was ranged from 58 to 83 μg L(-1). In order to overcome this problem, the hydrophobic substratum for bacterial attachment was selected as buoyant mat material of the artificial vegetation island. In this medium, total phosphate and total nitrogen were ranged from 190 to 1,060 μg L(-1) and from 4.9 to 9.1 mg L(-1), respectively. These concentrations were high enough for macrophytes growth. After launching 1,800 m(2) of AVI in Lake Paro, the macrophytes, Iris pseudoacorus and Iris ensata, grew well after five years of launching without the addition of fertilizer. Furthermore, fishes were plentiful under the artificial vegetation island, and ducks were observed on the artificial vegetation island. Bacteria using sunlight as energy source and self-designed ecotechnology can be used as an alternative method for the restoration of disturbed littoral zone in oligo-mesotrophic lakes.

Installation of an Artificial Vegetating Island in Oligomesotrophic Lake Paro, Korea

PubMed Central

Seo, Eun-Young; Kwon, Oh-Byung; Choi, Seung-Ik; Kim, Ji-Ho; Ahn, Tae-Seok

2013-01-01

After cut off of inflowing water, Lake Paro, an oligomesotrophic lake lost littoral zone, an important region for the aquatic ecosystem. For the first step of restoration, the artificial vegetation island was installed. The concentration of nutrients in lake water was not sufficient for the growth of macrophyte as total phosphate was ranged from 58 to 83 μg L−1. In order to overcome this problem, the hydrophobic substratum for bacterial attachment was selected as buoyant mat material of the artificial vegetation island. In this medium, total phosphate and total nitrogen were ranged from 190 to 1,060 μg L−1 and from 4.9 to 9.1 mg L−1, respectively. These concentrations were high enough for macrophytes growth. After launching 1,800 m2 of AVI in Lake Paro, the macrophytes, Iris pseudoacorus and Iris ensata, grew well after five years of launching without the addition of fertilizer. Furthermore, fishes were plentiful under the artificial vegetation island, and ducks were observed on the artificial vegetation island. Bacteria using sunlight as energy source and self-designed ecotechnology can be used as an alternative method for the restoration of disturbed littoral zone in oligo-mesotrophic lakes. PMID:23935437

Effects of Land-Cover Change, Floods, and Stream Position on Geomorphic Processes - Implications for Restoration Activities

USGS Publications Warehouse

Fitzpatrick, F.A.; ,

2001-01-01

A geomorphic study for North Fish Creek, a northern Wisconsin tributary to Lake Superior was analyzed to determine the hydrologic and geomorphic changes caused by clear-cut logging and agricultural activity. Discharge magnitude estimated with HEC-2 for full-channel capacities indicate that modern full-channel discharges are about twice as large as pre-1946 full-channel discharges. Flood-plain deposition rates were high along the transitional main stem after European settlement. Restoration and protection activities would be most effective if focused on watershed practices to reduce runoff and on channel restoration that reduce buff and bank erosion in the upper and transitional main stems.

Shrink film patterning by craft cutter: complete plastic chips with high resolution/high-aspect ratio channel.

PubMed

Taylor, Douglas; Dyer, David; Lew, Valerie; Khine, Michelle

2010-09-21

This paper presents a rapid, ultra-low-cost approach to fabricate microfluidic devices using a polyolefin shrink film and a digital craft cutter. The shrinking process (with a 95% reduction in area) results in relatively uniform and consistent microfluidic channels with smooth surfaces, vertical sidewalls, and high aspect ratio channels with lateral resolutions well beyond the tool used to cut them. The thermal bonding of the layers results in strongly bonded devices. Complex microfluidic designs are easily designed on the fly and protein assays are also readily integrated into the device. Full device characterization including channel consistency, optical properties, and bonding strength are assessed in this technical note.

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

Vincent, S.; Daiwile, A.; Devi, S. S.

Metallic glasses are a potential and compatible implant candidate for biomedical applications. In the present investigation, a comparative study between novel Zr 55Co 30Ti 15 and Cu 60Zr 20Ti 20 metallic glasses is carried out to evaluate in vitro biocompatibility using simulated body fluids. The bio-corrosion behavior of Zr- and Cu-based metallic glasses in different types of artificial body fluids such as artificial saliva solution, phosphate-buffered saline solution, artificial blood plasma solution, and Hank’s balanced saline solution is evaluated using potentiodynamic polarization studies at a constant body temperature of 310.15 K (37 °C). Surface morphology of samples after bio-corrosion experimentsmore » was observed by scanning electron microscopy. In vitro cytotoxicity test on glassy alloys were performed using human osteosarcoma cell line as per 10993-5 guidelines from International Organization for Standardization. As a result, the comparative study between Zr- and Cu-based glassy alloys provides vital information about the effect of elemental composition on biocompatibility of metallic glasses.« less

Enhancement in biological response of Ag-nano composite polymer membranes using plasma treatment for fabrication of efficient bio materials

NASA Astrophysics Data System (ADS)

Agrawal, Narendra Kumar; Sharma, Tamanna Kumari; Chauhan, Manish; Agarwal, Ravi; Vijay, Y. K.; Swami, K. C.

2016-05-01

Biomaterials are nonviable material used in medical devices, intended to interact with biological systems, which are becoming necessary for the development of artificial material for biological systems such as artificial skin diaphragm, valves for heart and kidney, lenses for eye etc. Polymers having novel properties like antibacterial, antimicrobial, high adhesion, blood compatibility and wettability are most suitable for synthesis of biomaterial, but all of these properties does not exist in any natural or artificial polymeric material. Nano particles and plasma treatment can offer these properties to the polymers. Hence a new nano-biomaterial has been developed by modifying the surface and chemical properties of Ag nanocomposite polymer membranes (NCPM) by Argon ion plasma treatment. These membranes were characterized using different techniques for surface and chemical modifications occurred. Bacterial adhesion and wettability were also tested for these membranes, to show direct use of this new class of nano-biomaterial for biomedical applications.

Biomimetic heterogeneous multiple ion channels: a honeycomb structure composite film generated by breath figures

NASA Astrophysics Data System (ADS)

Han, Keyu; Heng, Liping; Wen, Liping; Jiang, Lei

2016-06-01

We design a novel type of artificial multiple nanochannel system with remarkable ion rectification behavior via a facile breath figure (BF) method. Notably, even though the charge polarity in the channel wall reverses under different pH values, this nanofluidic device displays the same ionic rectification direction. Compared with traditional nanochannels, this composite multiple ion channel device can be more easily obtained and has directional ionic rectification advantages, which can be applied in many fields.We design a novel type of artificial multiple nanochannel system with remarkable ion rectification behavior via a facile breath figure (BF) method. Notably, even though the charge polarity in the channel wall reverses under different pH values, this nanofluidic device displays the same ionic rectification direction. Compared with traditional nanochannels, this composite multiple ion channel device can be more easily obtained and has directional ionic rectification advantages, which can be applied in many fields. Electronic supplementary information (ESI) available: Pore size distribution histograms of the AAO substrates; SEM images of the side view of pure AAO membranes and top view of the flat PI/AAO composite film; the current-time curves of the flat composite film; the current-voltage characteristics curves of pure AAO nanochannels with different mean pore diameters; CA of the two surfaces of the composite PI/AAO film, the structural formula of the polymer polyimide resin (PI), and solid surface zeta potential. See DOI: 10.1039/c6nr02506d

Amino acid residues involved in membrane insertion and pore formation of Clostridium botulinum C2 toxin.

PubMed

Lang, Alexander E; Neumeyer, Tobias; Sun, Jianjun; Collier, R John; Benz, Roland; Aktories, Klaus

2008-08-12

The actin-ADP-ribosylating Clostridium botulinum C2 toxin consists of the enzymatic component C2I and the binding component C2II. C2II forms heptameric channels involved in translocation of the enzymatic component into the target cell. On the basis of the heptameric toxin channel, we studied functional consequences of mutagenesis of amino acid residues probably lining the lumen of the toxin channel. Substitution of glutamate-399 of C2II with alanine blocked channel formation and cytotoxicity of the holotoxin. Although cytotoxicity and rounding up of cells by C2I were completely blocked by exchange of phenylalanine-428 with alanine, the mutation increased potassium conductance caused by C2II in artificial membranes by about 2-3-fold over that of wild-type toxin. In contrast to its effects on single-channel potassium conductance in artificial membranes, the F428A mutation delayed the kinetics of pore formation in lipid vesicles and inhibited the activity of C2II in promoting (86)Rb (+) release from preloaded intact cells after pH shift of the medium. Moreover, F428A C2II exhibited delayed and diminished formation of C2II aggregates at low pH, indicating major changes of the biophysical properties of the toxin. The data indicate that phenylalanine-428 of C2II plays a major role in conformational changes occurring during pore formation of the binding component of C2II.

Experimental demonstration of subcarrier multiplexed quantum key distribution system.

PubMed

Mora, José; Ruiz-Alba, Antonio; Amaya, Waldimar; Martínez, Alfonso; García-Muñoz, Víctor; Calvo, David; Capmany, José

2012-06-01

We provide, to our knowledge, the first experimental demonstration of the feasibility of sending several parallel keys by exploiting the technique of subcarrier multiplexing (SCM) widely employed in microwave photonics. This approach brings several advantages such as high spectral efficiency compatible with the actual secure key rates, the sharing of the optical fainted pulse by all the quantum multiplexed channels reducing the system complexity, and the possibility of upgrading with wavelength division multiplexing in a two-tier scheme, to increase the number of parallel keys. Two independent quantum SCM channels featuring a sifted key rate of 10 Kb/s/channel over a link with quantum bit error rate <2% is reported.

A comparison of different turbidite plays in the Yinggehai and Qiongdongnan Basins of the South China Sea

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

Cardwell, R.K.; Norris, J.W.

1996-12-31

Three different types of turbidite plays have been drilled in the Yinggehai and Qiongdongnan basins of the South China Sea: slope fan turbidites, bottomset turbidites, and channel fill turbidites. Each play type has a distinctive well log signature, lithology, seismic reflector geometry, and reservoir character. Slope fan turbidites are encountered in the YA 21-1-3 well. Well logs are characterized by a ratty SP curve, and mud logs indicate that the turbidites are composed of up to 80 m of sands and silts. Seismic profiles show that these turbidites are found in a distributary channel and levee system on the shelf.more » Bottomset turbidites are encountered in the LD 15-1-1 well. Well logs are characterized by an upward coarsening SP curve, and mud logs indicate that the turbidites are composed of up to 10 m of silty sand. Seismic profiles show these turbidites are deposited by the slumping of shelf sands during a continuous lowstand progradation. Channel fill turbidites are encountered in the LD 30-1-1 well. Well logs are characterized by a blocky SP curve, and mud logs indicate that the turbidites are composed of up to 100 m of massive sand. Seismic profiles show that these turbidites are associated with channel systems that trend parallel to the local basin axis. Distinct cut and fill geometries indicate that the turbidite sands were deposited in a preexisting channel cut.« less

A comparison of different turbidite plays in the Yinggehai and Qiongdongnan Basins of the South China Sea

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

Cardwell, R.K.; Norris, J.W.

1996-01-01

Three different types of turbidite plays have been drilled in the Yinggehai and Qiongdongnan basins of the South China Sea: slope fan turbidites, bottomset turbidites, and channel fill turbidites. Each play type has a distinctive well log signature, lithology, seismic reflector geometry, and reservoir character. Slope fan turbidites are encountered in the YA 21-1-3 well. Well logs are characterized by a ratty SP curve, and mud logs indicate that the turbidites are composed of up to 80 m of sands and silts. Seismic profiles show that these turbidites are found in a distributary channel and levee system on the shelf.more » Bottomset turbidites are encountered in the LD 15-1-1 well. Well logs are characterized by an upward coarsening SP curve, and mud logs indicate that the turbidites are composed of up to 10 m of silty sand. Seismic profiles show these turbidites are deposited by the slumping of shelf sands during a continuous lowstand progradation. Channel fill turbidites are encountered in the LD 30-1-1 well. Well logs are characterized by a blocky SP curve, and mud logs indicate that the turbidites are composed of up to 100 m of massive sand. Seismic profiles show that these turbidites are associated with channel systems that trend parallel to the local basin axis. Distinct cut and fill geometries indicate that the turbidite sands were deposited in a preexisting channel cut.« less

Optimal bit allocation for hybrid scalable/multiple-description video transmission over wireless channels

NASA Astrophysics Data System (ADS)

Jubran, Mohammad K.; Bansal, Manu; Kondi, Lisimachos P.

2006-01-01

In this paper, we consider the problem of optimal bit allocation for wireless video transmission over fading channels. We use a newly developed hybrid scalable/multiple-description codec that combines the functionality of both scalable and multiple-description codecs. It produces a base layer and multiple-description enhancement layers. Any of the enhancement layers can be decoded (in a non-hierarchical manner) with the base layer to improve the reconstructed video quality. Two different channel coding schemes (Rate-Compatible Punctured Convolutional (RCPC)/Cyclic Redundancy Check (CRC) coding and, product code Reed Solomon (RS)+RCPC/CRC coding) are used for unequal error protection of the layered bitstream. Optimal allocation of the bitrate between source and channel coding is performed for discrete sets of source coding rates and channel coding rates. Experimental results are presented for a wide range of channel conditions. Also, comparisons with classical scalable coding show the effectiveness of using hybrid scalable/multiple-description coding for wireless transmission.

Torque-actuated valves for microfluidics.

PubMed

Weibel, Douglas B; Kruithof, Maarten; Potenta, Scott; Sia, Samuel K; Lee, Andrew; Whitesides, George M

2005-08-01

This paper describes torque-actuated valves for controlling the flow of fluids in microfluidic channels. The valves consist of small machine screws (> or =500 microm) embedded in a layer of polyurethane cast above microfluidic channels fabricated in poly(dimethylsiloxane) (PDMS). The polyurethane is cured photochemically with the screws in place; on curing, it bonds to the surrounding layer of PDMS and forms a stiff layer that retains an impression of the threads of the screws. The valves were separated from the ceiling of microfluidic channels by a layer of PDMS and were integrated into channels using a simple procedure compatible with soft lithography and rapid prototyping. Turning the screws actuated the valves by collapsing the PDMS layer between the valve and channel, controlling the flow of fluids in the underlying channels. These valves have the useful characteristic that they do not require power to retain their setting (on/off). They also allow settings between "on" and "off" and can be integrated into portable, disposable microfluidic devices for carrying out sandwich immunoassays.

Rapid Prototyping Technique for the Fabrication of Millifluidic Devices for Polymer Formulations

NASA Astrophysics Data System (ADS)

Cabral, Joao; Harrison, Christopher; Eric, Amis; Karim, Alamgir

2003-03-01

We describe a rapid prototyping technique for the fabrication of 600 micron deep fluidic channels in a solvent-resistant polymeric matrix. Using a conventional illumination source, a laser-jet printed mask, and a commercially available thioelene-based adhesive, we demonstrate the fabrication of fluidic channels which are impervious to a wide range of solvents. The fabrication of channels with this depth by conventional lithography would be both challenging and time-consuming. We demonstrate two lithography methods: one which fabricates channels sealed between glass plates (closed face) and one which fabricates structures on a single plate (open-faced). Furthermore, we demonstrate that this technology can be used to fabricate channels with a depth which varies linearly with distance. The latter is completely compatible with silicone replication technniques. Additionally, we demonstrate that siloxane-based elastomer molds of these channels can be readily made for aqueous applications. Applications to on-line phase mapping of polymer solutions (PEO-Water-Salt) and off line phase separation studies will be discussed.

Cut flowers: a potential pesticide hazard.

PubMed Central

Morse, D L; Baker, E L; Landrigan, P J

1979-01-01

Following reports of ten cases of possible organophosphate pesticide poisoning in florists exposed to pesticide residues on cut flowers, we conducted a prospective random-sample survey to determine residual pesticide levels on flowers imported into the United States via Miami, Florida. A sample of all flowers imported into Miami on three days in January 1977 showed that 18 (17.7 per cent) of 105 lots contained pesticide residue levels greater than 5 ppm, and that three lots had levels greater than 400 ppm. Azodrin (monocrotophos) was the most important contaminant with levels of 7.7--4,750 ppm detected in nine lots. We examined 20 quarantine workers in Miami and 12 commercial florists exposed to contaminated flowers. Occasional nonspecific symptoms compatible with possible organophosphate exposure were noted, but we found no abnormalities in plasma or red blood cell cholinesterase levels. This study documents a previously unrecognized potential source of occupational pesticide exposure and suggests that safety standards should be set for residue levels on cut flowers. PMID:420356

Ion flux through membrane channels--an enhanced algorithm for the Poisson-Nernst-Planck model.

PubMed

Dyrka, Witold; Augousti, Andy T; Kotulska, Malgorzata

2008-09-01

A novel algorithmic scheme for numerical solution of the 3D Poisson-Nernst-Planck model is proposed. The algorithmic improvements are universal and independent of the detailed physical model. They include three major steps: an adjustable gradient-based step value, an adjustable relaxation coefficient, and an optimized segmentation of the modeled space. The enhanced algorithm significantly accelerates the speed of computation and reduces the computational demands. The theoretical model was tested on a regular artificial channel and validated on a real protein channel-alpha-hemolysin, proving its efficiency. (c) 2008 Wiley Periodicals, Inc.

Ultra-Compact Multitip Scanning Probe Microscope with an Outer Diameter of 50 mm

NASA Astrophysics Data System (ADS)

Cherepanov, Vasily; Zubkov, Evgeny; Junker, Hubertus; Korte, Stefan; Blab, Marcus; Coenen, Peter; Voigtländer, Bert

We present a multitip scanning tunneling microscope (STM) where four independent STM units are integrated on a diameter of 50 mm. The coarse positioning of the tips is done under the control of an optical microscope or an SEM in vacuum. The heart of this STM is a new type of piezoelectric coarse approach called Koala Drive which can have a diameter greater than 2.5 mm and a length smaller than 10 mm. Alternating movements of springs move a central tube which holds the STM tip or AFM sensor. This new operating principle provides a smooth travel sequence and avoids shaking which is intrinsically present for nanopositioners based on inertial motion with saw tooth driving signals. Inserting the Koala Drive in a piezo tube for xyz-scanning integrates a complete STM inside a 4 mm outer diameter piezo tube of <10 mm length. The use of the Koala Drive makes the scanning probe microscopy design ultra-compact and accordingly leads to a high mechanical stability. The drive is UHV, low temperature, and magnetic field compatible. The compactness of the Koala Drive allows building a four-tip STM as small as a single-tip STM with a drift of <0.2 nm/min and lowest resonance frequencies of 2.5 (xy) and 5.5 kHz (z). We present examples of the performance of the multitip STM designed using the Koala Drive.

Auqakuh Valles

NASA Image and Video Library

2002-06-17

The ancient sinuous river channel shown in this image by NASA Mars Odyssey spacecraft was likely carved by water early in Mars history. Auqakuh Valles cuts through a remarkable series of rock layers that were deposited and then subsequently eroded.

Large woody debris volumes and accumulation rates in cleaned streams in redwood forest in southern Humboldt County, California

Treesearch

John Wooster; Sue Hilton

2004-01-01

Large woody debris (LWD) was inventoried in 1999 in five streams where LWD was removed in the early 1980s, and no LWD has been artificially introduced since. All study sites are second order channels near the confluence of the South Fork and main-stem Eel River, California. Watershed contributing areas range from 4.7 to 17.4 km², and mean active channel widths...

On the integration of ultrananocrystalline diamond (UNCD) with CMOS chip

DOE PAGES

Mi, Hongyi; Yuan, Hao -Chih; Seo, Jung -Hun; ...

2017-03-27

A low temperature deposition of high quality ultrananocrystalline diamond (UNCD) film onto a finished Si-based CMOS chip was performed to investigate the compatibility of the UNCD deposition process with CMOS devices for monolithic integration of MEMS on Si CMOS platform. DC and radio-frequency performances of the individual PMOS and NMOS devices on the CMOS chip before and after the UNCD deposition were characterized. Electrical characteristics of CMOS after deposition of the UNCD film remained within the acceptable ranges, namely showing small variations in threshold voltage V th, transconductance g m, cut-off frequency f T and maximum oscillation frequency f max.more » Finally, the results suggest that low temperature UNCD deposition is compatible with CMOS to realize monolithically integrated CMOS-driven MEMS/NEMS based on UNCD.« less

On the integration of ultrananocrystalline diamond (UNCD) with CMOS chip

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

Mi, Hongyi; Yuan, Hao -Chih; Seo, Jung -Hun

A low temperature deposition of high quality ultrananocrystalline diamond (UNCD) film onto a finished Si-based CMOS chip was performed to investigate the compatibility of the UNCD deposition process with CMOS devices for monolithic integration of MEMS on Si CMOS platform. DC and radio-frequency performances of the individual PMOS and NMOS devices on the CMOS chip before and after the UNCD deposition were characterized. Electrical characteristics of CMOS after deposition of the UNCD film remained within the acceptable ranges, namely showing small variations in threshold voltage V th, transconductance g m, cut-off frequency f T and maximum oscillation frequency f max.more » Finally, the results suggest that low temperature UNCD deposition is compatible with CMOS to realize monolithically integrated CMOS-driven MEMS/NEMS based on UNCD.« less

Seismic analysis of the frame structure reformed by cutting off column and jacking based on stiffness ratio

NASA Astrophysics Data System (ADS)

Zhao, J. K.; Xu, X. S.

2017-11-01

The cutting off column and jacking technology is a method for increasing story height, which has been widely used and paid much attention in engineering. The stiffness will be changed after the process of cutting off column and jacking, which directly affects the overall seismic performance. It is usually necessary to take seismic strengthening measures to enhance the stiffness. A five story frame structure jacking project in Jinan High-tech Zone was taken as an example, and three finite element models were established which contains the frame model before lifting, after lifting and after strengthening. Based on the stiffness, the dynamic time-history analysis was carried out to research its seismic performance under the EL-Centro seismic wave, the Taft seismic wave and the Tianjin artificial seismic wave. The research can provide some guidance for the design and construction of the entire jack lifting structure.

Advanced Techniques of Artificial Networks Design for Radio Signal Detection

NASA Astrophysics Data System (ADS)

Danilin, S. N.; Shchanikov, S. A.; Iventev, A. A.; Zuev, A. D.

2018-05-01

This paper is concerned with the issue of secure radio communication of data between manned aircrafts, unmanned drones and control services. It is indicated that the use of artificial neural networks (ANN) enables correct identification of messages transmitted through radio channels and enhances identification quality by every measure. The authors designed and implemented a simulation modeling technology for ANN development, which enables signal detection with required accuracy in the context of noise jamming, natural and other types of noise.

Collapse susceptibility mapping in karstified gypsum terrain (Sivas basin - Turkey) by conditional probability, logistic regression, artificial neural network models

NASA Astrophysics Data System (ADS)

Yilmaz, Isik; Keskin, Inan; Marschalko, Marian; Bednarik, Martin

2010-05-01

This study compares the GIS based collapse susceptibility mapping methods such as; conditional probability (CP), logistic regression (LR) and artificial neural networks (ANN) applied in gypsum rock masses in Sivas basin (Turkey). Digital Elevation Model (DEM) was first constructed using GIS software. Collapse-related factors, directly or indirectly related to the causes of collapse occurrence, such as distance from faults, slope angle and aspect, topographical elevation, distance from drainage, topographic wetness index- TWI, stream power index- SPI, Normalized Difference Vegetation Index (NDVI) by means of vegetation cover, distance from roads and settlements were used in the collapse susceptibility analyses. In the last stage of the analyses, collapse susceptibility maps were produced from CP, LR and ANN models, and they were then compared by means of their validations. Area Under Curve (AUC) values obtained from all three methodologies showed that the map obtained from ANN model looks like more accurate than the other models, and the results also showed that the artificial neural networks is a usefull tool in preparation of collapse susceptibility map and highly compatible with GIS operating features. Key words: Collapse; doline; susceptibility map; gypsum; GIS; conditional probability; logistic regression; artificial neural networks.

Microoptical artificial compound eyes: from design to experimental verification of two different concepts

NASA Astrophysics Data System (ADS)

Duparré, Jacques; Wippermann, Frank; Dannberg, Peter; Schreiber, Peter; Bräuer, Andreas; Völkel, Reinhard; Scharf, Toralf

2005-09-01

Two novel objective types on the basis of artificial compound eyes are examined. Both imaging systems are well suited for fabrication using microoptics technology due to the small required lens sags. In the apposition optics a microlens array (MLA) and a photo detector array of different pitch in its focal plane are applied. The image reconstruction is based on moire magnification. Several generations of demonstrators of this objective type are manufactured by photo lithographic processes. This includes a system with opaque walls between adjacent channels and an objective which is directly applied onto a CMOS detector array. The cluster eye approach, which is based on a mixture of superposition compound eyes and the vision system of jumping spiders, produces a regular image. Here, three microlens arrays of different pitch form arrays of Keplerian microtelescopes with tilted optical axes, including a field lens. The microlens arrays of this demonstrator are also fabricated using microoptics technology, aperture arrays are applied. Subsequently the lens arrays are stacked to the overall microoptical system on wafer scale. Both fabricated types of artificial compound eye imaging systems are experimentally characterized with respect to resolution, sensitivity and cross talk between adjacent channels. Captured images are presented.

Biosensor analysis of natural and artificial sweeteners in intact taste epithelium.

PubMed

Zhang, Fenni; Zhang, Qian; Zhang, Diming; Lu, Yanli; Liu, Qingjun; Wang, Ping

2014-04-15

Sweeteners are commonly used as food additives in our daily life, which, however, have been causing a number of undesirable diseases since the last century. Therefore, the detection and quantification of sweeteners are of great value for food safety. In this study, we used a taste biosensor to measure and analyze different sweeteners, both natural and artificial sweeteners included. Electrophysiological activities from taste epithelium were detected by the multi-channel biosensors and analyzed with spatiotemporal methods. The longtime signal result showed different temporal-frequency properties with stimulations of individual sweeteners such as glucose, sucrose, saccharin, and cyclamate, while the multi-channel results in our study revealed the spatial expression of taste epithelium to sweet stimuli. Furthermore, in the analysis of sweetener with different concentrations, the result showed obvious dose-dependent increases in signal responses of the taste epithelium, which indicated promising applications in sweetness evaluation. Besides, the mixture experiment of two natural sweeteners with a similar functional unit (glucose and sucrose) presented two signal patterns, which turned out to be similar with responses of each individual stimulus involved. The biosensor analysis of common sweeteners provided new approaches for both natural and artificial sweeteners evaluation. © 2013 Published by Elsevier B.V.

Laminated microchannel devices, mixing units and method of making same

DOEpatents

Bennett, Wendy D [Kennewick, WA; Hammerstrom, Donald J [West Richland, WA; Martin, Peter M [Kennewick, WA; Matson, Dean W [Kennewick, WA

2002-10-17

A laminated microchannel device is described in which there is a unit operation process layer that has longitudinal channel. The longitudinal channel is cut completely through the layer in which the unit process operation resides. Both the device structure and method of making the device provide significant advantages in terms of simplicity and efficiency. A static mixing unit that can be incorporated in the laminated microchannel device is also described.

Design and performance of heart assist or artificial heart control systems

NASA Technical Reports Server (NTRS)

Webb, J. A., Jr.; Gebben, V. D.

1978-01-01

The factors leading to the design of a controlled driving system for either a heart assist pump or artificial heart are discussed. The system provides square pressure waveform to drive a pneumatic-type blood pump. For assist usage the system uses an R-wave detector circuit that can detect the R-wave of the electrocardiogram in the presence of electrical disturbances. This circuit provides a signal useful for synchronizing an assist pump with the natural heart. It synchronizes a square wave circuit, the output of which is converted into square waveforms of pneumatic pressure suitable for driving both assist device and artificial heart. The pressure levels of the driving waveforms are controlled by means of feedback channels to maintain physiological regulation of the artificial heart's output flow. A more compact system that could achieve similar regulatory characteristics is also discussed.

Prediction of surface roughness in turning of Ti-6Al-4V using cutting parameters, forces and tool vibration

NASA Astrophysics Data System (ADS)

Sahu, Neelesh Kumar; Andhare, Atul B.; Andhale, Sandip; Raju Abraham, Roja

2018-04-01

Present work deals with prediction of surface roughness using cutting parameters along with in-process measured cutting force and tool vibration (acceleration) during turning of Ti-6Al-4V with cubic boron nitride (CBN) inserts. Full factorial design is used for design of experiments using cutting speed, feed rate and depth of cut as design variables. Prediction model for surface roughness is developed using response surface methodology with cutting speed, feed rate, depth of cut, resultant cutting force and acceleration as control variables. Analysis of variance (ANOVA) is performed to find out significant terms in the model. Insignificant terms are removed after performing statistical test using backward elimination approach. Effect of each control variables on surface roughness is also studied. Correlation coefficient (R2 pred) of 99.4% shows that model correctly explains the experiment results and it behaves well even when adjustment is made in factors or new factors are added or eliminated. Validation of model is done with five fresh experiments and measured forces and acceleration values. Average absolute error between RSM model and experimental measured surface roughness is found to be 10.2%. Additionally, an artificial neural network model is also developed for prediction of surface roughness. The prediction results of modified regression model are compared with ANN. It is found that RSM model and ANN (average absolute error 7.5%) are predicting roughness with more than 90% accuracy. From the results obtained it is found that including cutting force and vibration for prediction of surface roughness gives better prediction than considering only cutting parameters. Also, ANN gives better prediction over RSM models.

The Influence of the Shape of Model Hydrometeors on the Formation of Discharge between an Artificial-Thunderstorm Cell and the Ground

NASA Astrophysics Data System (ADS)

Temnikov, A. G.; Chernenskii, L. L.; Orlov, A. V.; Lysov, N. Yu.; Belova, O. S.; Gerastenok, T. K.; Zhuravkova, D. S.

2017-12-01

We have experimentally studied how arrays of model coarse hydrometeors influence the initiation and propagation of discharge between an artificial-thunderstorm cell of negative or positive polarity and the ground. It is established for the first time that the probability of initiation and stimulation of a channeled discharge between negatively or positively charged cloud and the ground significantly depends on the shape and size of coarse hydrometeors occurring near the thunderstorm cell boundaries. The obtained results can be used in developing methods for the artificial initiation of the cloud-ground type lightning of both polarities and targeted discharge of thunderstorm clouds.

High-sensitivity two-terminal magnetoresistance devices using InGaAs/AlGaAs two-dimensional channel on GaAs substrate

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

Wu, Di-Cheng; Pan, You-Wei; Lin, Shih-Wei

2016-04-25

We demonstrate experimentally the two-terminal magnetic sensors exhibiting an extraordinary magneto-resistance effect by using an InGaAs quantum well channel with a metal-shunting structure. A high magneto-resistance of 17.3% and a sensitivity of 488.1 Ω/T have been obtained at 1 T and room temperature with our geometrical design. The two-contact configuration and the high-mobility electron transistor-compatible epitaxy structure make the devices promising for high-sensitivity magnetic sensing integration and applications.

Monolithic integration of an InP-based 4 × 25 GHz photodiode array to an O-band arrayed waveguide grating demultiplexer

NASA Astrophysics Data System (ADS)

Ye, Han; Han, Qin; Lv, Qianqian; Pan, Pan; An, Junming; Yang, Xiaohong

2017-12-01

We demonstrate the monolithic integration of a uni-traveling carrier photodiode array with a 4 channel, O-band arrayed waveguide grating demultiplexer on the InP platform by the selective area growth technique. An extended coupling layer at the butt-joint is adopted to ensure both good fabrication compatibility and high photodiode quantum efficiency of 77%. The fabricated integrated chip exhibits a uniform bandwidth over 25 GHz for each channel and a crosstalk below -22 dB.

Understanding carbon nanotube channel formation in the lipid membrane

NASA Astrophysics Data System (ADS)

Choi, Moon-ki; Kim, Hyunki; Lee, Byung Ho; Kim, Teayeop; Rho, Junsuk; Kim, Moon Ki; Kim, Kyunghoon

2018-03-01

Carbon nanotubes (CNTs) have been considered a prominent nano-channel in cell membranes because of their prominent ion-conductance and ion-selectivity, offering agents for a biomimetic channel platform. Using a coarse-grained molecular dynamics simulation, we clarify a construction mechanism of vertical CNT nano-channels in a lipid membrane for a long period, which has been difficult to observe in previous CNT-lipid interaction simulations. The result shows that both the lipid coating density and length of CNT affect the suitable fabrication condition for a vertical and stable CNT channel. Also, simulation elucidated that a lipid coating on the surface of the CNT prevents the CNT from burrowing into the lipid membrane and the vertical channel is stabilized by the repulsion force between the lipids in the coating and membrane. Our study provides an essential understanding of how CNTs can form stable and vertical channels in the membrane, which is important for designing new types of artificial channels as biosensors for bio-fluidic studies.

Variable Temperature Scanning Tunneling Microscopy

DTIC Science & Technology

1991-07-01

Tomazin, both Electrical Engineering. Build a digital integrator for the STM feedback loop: Kyle Drewry, Electrical Engineering. Write an AutoLisp ...program to automate the AutoCad design of UHV-STM chambers: Alfred Pierce (minority), Mechanical Engineering. Design a 32-bit interface board for the EISA

Non Contacting Evaluation of Strains and Cracking Using Optical and Infrared Imaging Techniques

DTIC Science & Technology

1988-08-22

Compatible Zenith Z-386 microcomputer with plotter II. 3-D Motion Measurinq System 1. Complete OPTOTRAK three dimensional digitizing system. System includes...acquisition unit - 16 single ended analog input channels 3. Data Analysis Package software (KINEPLOT) 4. Extra OPTOTRAK Camera (max 224 per system

Acoustic actuation of in situ fabricated artificial cilia

NASA Astrophysics Data System (ADS)

Orbay, Sinem; Ozcelik, Adem; Bachman, Hunter; Huang, Tony Jun

2018-02-01

We present on-chip acoustic actuation of in situ fabricated artificial cilia. Arrays of cilia structures are UV polymerized inside a microfluidic channel using a photocurable polyethylene glycol (PEG) polymer solution and photomasks. During polymerization, cilia structures are attached to a silane treated glass surface inside the microchannel. Then, the cilia structures are actuated using acoustic vibrations at 4.6 kHz generated by piezo transducers. As a demonstration of a practical application, DI water and fluorescein dye solutions are mixed inside a microfluidic channel. Using pulses of acoustic excitations, and locally fabricated cilia structures within a certain region of the microchannel, a waveform of mixing behavior is obtained. This result illustrates one potential application wherein researchers can achieve spatiotemporal control of biological microenvironments in cell stimulation studies. These acoustically actuated, in situ fabricated, cilia structures can be used in many on-chip applications in biological, chemical and engineering studies.

Large area scanning probe microscope in ultra-high vacuum demonstrated for electrostatic force measurements on high-voltage devices.

PubMed

Gysin, Urs; Glatzel, Thilo; Schmölzer, Thomas; Schöner, Adolf; Reshanov, Sergey; Bartolf, Holger; Meyer, Ernst

2015-01-01

The resolution in electrostatic force microscopy (EFM), a descendant of atomic force microscopy (AFM), has reached nanometre dimensions, necessary to investigate integrated circuits in modern electronic devices. However, the characterization of conducting or semiconducting power devices with EFM methods requires an accurate and reliable technique from the nanometre up to the micrometre scale. For high force sensitivity it is indispensable to operate the microscope under high to ultra-high vacuum (UHV) conditions to suppress viscous damping of the sensor. Furthermore, UHV environment allows for the analysis of clean surfaces under controlled environmental conditions. Because of these requirements we built a large area scanning probe microscope operating under UHV conditions at room temperature allowing to perform various electrical measurements, such as Kelvin probe force microscopy, scanning capacitance force microscopy, scanning spreading resistance microscopy, and also electrostatic force microscopy at higher harmonics. The instrument incorporates beside a standard beam deflection detection system a closed loop scanner with a scan range of 100 μm in lateral and 25 μm in vertical direction as well as an additional fibre optics. This enables the illumination of the tip-sample interface for optically excited measurements such as local surface photo voltage detection. We present Kelvin probe force microscopy (KPFM) measurements before and after sputtering of a copper alloy with chromium grains used as electrical contact surface in ultra-high power switches. In addition, we discuss KPFM measurements on cross sections of cleaved silicon carbide structures: a calibration layer sample and a power rectifier. To demonstrate the benefit of surface photo voltage measurements, we analysed the contact potential difference of a silicon carbide p/n-junction under illumination.

25 CFR 309.11 - What are examples of jewelry that are Indian products?

Code of Federal Regulations, 2014 CFR

2014-04-01

... limited to, silver, gold, turquoise, coral, lapis, jet, nickel silver, glass bead, copper, wood, shell... channel inlay gold rings, cut glass bead rosette earrings, wooden horse stick pins, and medicine wheel...

25 CFR 309.11 - What are examples of jewelry that are Indian products?

Code of Federal Regulations, 2013 CFR

2013-04-01

... limited to, silver, gold, turquoise, coral, lapis, jet, nickel silver, glass bead, copper, wood, shell... channel inlay gold rings, cut glass bead rosette earrings, wooden horse stick pins, and medicine wheel...

25 CFR 309.11 - What are examples of jewelry that are Indian products?

Code of Federal Regulations, 2012 CFR

2012-04-01

... limited to, silver, gold, turquoise, coral, lapis, jet, nickel silver, glass bead, copper, wood, shell... channel inlay gold rings, cut glass bead rosette earrings, wooden horse stick pins, and medicine wheel...

Northeast Artificial Intelligence Consortium (NAIC). Volume 12. Computer Architecture for Very Large Knowledge Bases

DTIC Science & Technology

1990-12-01

data rate to the electronics would be much lower on the average and the data much "richer" in information. Intelligent use of...system bottleneck, a high data rate should be provided by I/O systems. 2. machines with intelligent storage management specially designed for logic...management information processing, surveillance sensors, intelligence data collection and handling, solid state sciences, electromagnetics, and propagation, and electronic reliability/maintainability and compatibility.

High-Gain AlxGa1-xAs/GaAs Transistors For Neural Networks

NASA Technical Reports Server (NTRS)

Kim, Jae-Hoon; Lin, Steven H.

1991-01-01

High-gain AlxGa1-xAs/GaAs npn double heterojunction bipolar transistors developed for use as phototransistors in optoelectronic integrated circuits, especially in artificial neural networks. Transistors perform both photodetection and saturating-amplification functions of neurons. Good candidates for such application because structurally compatible with laser diodes and light-emitting diodes, detect light, and provide high current gain needed to compensate for losses in holographic optical elements.

[Experience in the use of equipment for ECG system analysis in municipal polyclinics].

PubMed

Bondarenko, A A

2006-01-01

Two electrocardiographs, an analog-digital electrocardiograph with preliminary analog filtering of signal and a smart cardiograph implemented as a PC-compatible device without preliminary analog filtering, are considered. Advantages and disadvantages of ECG systems based on artificial intelligence are discussed. ECG interpretation modes provided by the two electrocardiographs are considered. The reliability of automatic ECG interpretation is assessed. Problems of rational use of automated ECG processing systems are discussed.

Study on Circular Complex viewed from Environmental Systems

NASA Astrophysics Data System (ADS)

Takeguchi, Tomoo; Adachi, Katsushige; Yoshikawa, Akira; Hiratsuka, Akira; Tsujino, Ryoji; Iguchi, Manabu

In machining processes, cutting fluids are generally used for cooling and lubricating workpieces at the point cutting. However, these fluids frequently include chlorine, sulfur, phosphorus, or other additives. The chemicals not only become a mist affecting the health of workers engaged in the processing but also make the workshop environment worse. In particular, the chlorine becomes one of the causes of global warming by treating waste oil under high temperature conditions. It is furthermore said that huge cost beyond the purchase cost of oil occurs and dioxins (carcinogen) usually exist in the waste oil. Therefore, an environmentally-friendly cooling-air cutting system is required from the standpoint of green manufacturing. This system has been noted as a technique to solve the issues against the environment mentioned above. In the cooling-air cutting processing, the amount of CO2 emission shows a low value compared with the dry cutting one which uses oil. It is therefore thought that the cooling-air cutting system is a very important processing technique as an environmental countermeasure. At present, in strictly economic and environmental situations, the compatibility of the betterment of production efficiency with the improvement of environment is a subject in the actual spot of a cut processing. This study deals with the test results of cooling-air drilling performance from the viewpoint of taking green manufacturing into account. The workpiece made of die steel SKDll was manufactured by the cooling-air drilling performance at a revolution of 840 rpm and a temperature of -20°C with a high-speed steel drill (SKH56). The results were compared with those for the dry cutting performance. The main results obtained in this study are as follows: 1) The tool life for cooling-air drilling performance was about 6 times as long as that for the dry cutting performance. 2) The chip temperature for cooling-air drilling was 220°C lower than that for the dry cutting performance.

Development of spiral wave in a regular network of excitatory neurons due to stochastic poisoning of ion channels

NASA Astrophysics Data System (ADS)

Wu, Xinyi; Ma, Jun; Li, Fan; Jia, Ya

2013-12-01

Some experimental evidences show that spiral wave could be observed in the cortex of brain, and the propagation of this spiral wave plays an important role in signal communication as a pacemaker. The profile of spiral wave generated in a numerical way is often perfect while the observed profile in experiments is not perfect and smooth. In this paper, formation and development of spiral wave in a regular network of Morris-Lecar neurons, which neurons are placed on nodes uniformly in a two-dimensional array and each node is coupled with nearest-neighbor type, are investigated by considering the effect of stochastic ion channels poisoning and channel noise. The formation and selection of spiral wave could be detected as follows. (1) External forcing currents with diversity are imposed on neurons in the network of excitatory neurons with nearest-neighbor connection, a target-like wave emerges and its potential mechanism is discussed; (2) artificial defects and local poisoned area are selected in the network to induce new wave to interact with the target wave; (3) spiral wave can be induced to occupy the network when the target wave is blocked by the artificial defects or poisoned area with regular border lines; (4) the stochastic poisoning effect is introduced by randomly modifying the border lines (areas) of specific regions in the network. It is found that spiral wave can be also developed to occupy the network under appropriate poisoning ratio. The process of growth for the poisoned area of ion channels poisoning is measured, the effect of channels noise is also investigated. It is confirmed that perfect spiral wave emerges in the network under gradient poisoning even if the channel noise is considered.

Aviation Design Software

NASA Technical Reports Server (NTRS)

1997-01-01

DARcorporation developed a General Aviation CAD package through a Small Business Innovation Research contract from Langley Research Center. This affordable, user-friendly preliminary design system for General Aviation aircraft runs on the popular 486 IBM-compatible personal computers. Individuals taking the home-built approach, small manufacturers of General Aviation airplanes, as well as students and others interested in the analysis and design of aircraft are possible users of the package. The software can cut design and development time in half.

Optimum design of space storable gas/liquid coaxial injectors.

NASA Technical Reports Server (NTRS)

Burick, R. J.

1972-01-01

Review of the results of a program of single-element, cold-flow/hot-fire experiments performed for the purpose of establishing design criteria for a high-performance gas/liquid (FLOX/CH4) coaxial injector. The approach and the techniques employed resulted in the direct design of an injector that met or exceeded the performance and chamber compatibility goals of the program without any need for the traditional 'cut-and-try' development methods.

Growth and development of planted northern red oak on bulldozed skidroads after clearcutting in Appalachian hardwoods

Treesearch

James N. Kochenderfer; Mary Beth Adams; Gary W. Miller; Frederica Wood

2006-01-01

Artificial regeneration of northern red oak in Appalachian clearcuts on mesic sites is hindered by accessibility and competition from developing vegetation. The use of skidroads as a planting medium was evaluated on two clearcuts with contrasting aspects in north central West Virginia. Stratified acorns were planted in tree shelters at three positions (cut, middle,...

Methods to Improve Establishment and Growth of Bottomland Hardwood Artificial Regeneration

Treesearch

Callie Jo Schweitzer; Emile S. Gardiner; John A. Stanturf; Andrew W. Ezell

1999-01-01

With ongoing attempts to reforest both cut-over and abandoned agricultural land in the lower Mississippi alluvial plain, it has become evident that there exists a need for an efficient regeneration system that makes biological and economic sense. Also, there is a need to address how to minimize oomoetitkm from invading weeds, to deter predation by small mammals, and...

Acorn Weevils, Rodents, and Deer All Contribute to Oak-Regeneration Difficulties in Pennsylvania

Treesearch

David A. Marquis; Philip L. Eckert; Benjamin A. Roach

1976-01-01

In parts of Pennsylvania, oak regeneration after harvest cutting or natural disturbances has been very poor. Studies on the Tuscarora State Forest suggest that the primary cause of natural regeneration failure may be a lack of viable acorns; on some sites acorn insects and rodents destroy nearly all acorns, even in good seed years. Artificial regeneration is not...

Wear measurement of the cutting edge of superhard turning tools using TLA technique

NASA Astrophysics Data System (ADS)

Vasváry, L.; Ditrói, F.; Takács, S.; Szabó, Z.; Szűcs, J.; Kundrák, J.; Mahunka, I.

1994-03-01

Wear measurement on superhard boron nitride and artificial diamond turning tools was performed using thin layer activation (TLA) technique. The samples were irradiated in two different geometries to improve the sensitivity of the method and change the region of wear to be investigated. The most proper irradiation parameters and nuclear reactions were investigated for both kind of tools.

Ammonium sorption to channel and riparian sediments: A transient storage pool for dissolved inorganic nitrogen

USGS Publications Warehouse

Triska, Frank J.; Jackman, Alan P.; Duff, John H.; Avanzino, Ronald J.

1994-01-01

Sediment (0.5 mm–2.0 mm grain size) was incubated in nylon bags (200 μm mesh) below the water table in the channel and in two transects of shallow wells perpendicular to the banks (to 18 m) of a third-order stream during August, 1987. One transect of wells drained steep old-growth forest, and the other a steep 23 year-old clear-cut partially regenerated in alder. At approximately 6-week intervals between October, 1987, and June, 1988, bags were retrieved. Total exchangeable ammonium was determined on sediment, and dissolved oxygen, nitrate and ammonium were determined in stream and well water. Exchangeable ammonium ranged from 10 μeq/100 g of sediment in the stream where nitrification potential and subsurface exchange with stream water were high, to 115 μeq/100 g sediment 18 m inland where channel water-groundwater mixing and nitrification potential were both low. Sorbed ammonium was highest during summer/autumn base flow and lowest during winter storm flow. Both channel and well water contained measurable dissolved oxygen at all times. Ammonium concentration was typically < 10 μg-N/L in channel water, increased with distance inland, but did not exceed 365 μg-N/L at any site. Nitrate concentration was typically higher in well water than channel water. Nitrate levels increased dramatically in wells at the base of the clear-cut following the onset of autumn rains. The results indicate a potential for temporary storage of ammonium on riparian sediments which may influence biotic nitrogen cycling, and alter the timing and form of dissolved inorganic nitrogen transport from the watershed.

Development of a low cost high precision three-layer 3D artificial compound eye.

PubMed

Zhang, Hao; Li, Lei; McCray, David L; Scheiding, Sebastian; Naples, Neil J; Gebhardt, Andreas; Risse, Stefan; Eberhardt, Ramona; Tünnermann, Andreas; Yi, Allen Y

2013-09-23

Artificial compound eyes are typically designed on planar substrates due to the limits of current imaging devices and available manufacturing processes. In this study, a high precision, low cost, three-layer 3D artificial compound eye consisting of a 3D microlens array, a freeform lens array, and a field lens array was constructed to mimic an apposition compound eye on a curved substrate. The freeform microlens array was manufactured on a curved substrate to alter incident light beams and steer their respective images onto a flat image plane. The optical design was performed using ZEMAX. The optical simulation shows that the artificial compound eye can form multiple images with aberrations below 11 μm; adequate for many imaging applications. Both the freeform lens array and the field lens array were manufactured using microinjection molding process to reduce cost. Aluminum mold inserts were diamond machined by the slow tool servo method. The performance of the compound eye was tested using a home-built optical setup. The images captured demonstrate that the proposed structures can successfully steer images from a curved surface onto a planar photoreceptor. Experimental results show that the compound eye in this research has a field of view of 87°. In addition, images formed by multiple channels were found to be evenly distributed on the flat photoreceptor. Additionally, overlapping views of the adjacent channels allow higher resolution images to be re-constructed from multiple 3D images taken simultaneously.

Surface science and model catalysis with ionic liquid-modified materials.

PubMed

Steinrück, H-P; Libuda, J; Wasserscheid, P; Cremer, T; Kolbeck, C; Laurin, M; Maier, F; Sobota, M; Schulz, P S; Stark, M

2011-06-17

Materials making use of thin ionic liquid (IL) films as support-modifying functional layer open up a variety of new possibilities in heterogeneous catalysis, which range from the tailoring of gas-surface interactions to the immobilization of molecularly defined reactive sites. The present report reviews recent progress towards an understanding of "supported ionic liquid phase (SILP)" and "solid catalysts with ionic liquid layer (SCILL)" materials at the microscopic level, using a surface science and model catalysis type of approach. Thin film IL systems can be prepared not only ex-situ, but also in-situ under ultrahigh vacuum (UHV) conditions using atomically well-defined surfaces as substrates, for example by physical vapor deposition (PVD). Due to their low vapor pressure, these systems can be studied in UHV using the full spectrum of surface science techniques. We discuss general strategies and considerations of this approach and exemplify the information available from complementary methods, specifically photoelectron spectroscopy and surface vibrational spectroscopy. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation of clean surfaces and Se vacancy formation in Bi2Se3 by ion bombardment and annealing

NASA Astrophysics Data System (ADS)

Zhou, Weimin; Zhu, Haoshan; Valles, Connie M.; Yarmoff, Jory A.

2017-08-01

Bismuth Selenide (Bi2Se3) is a topological insulator (TI) with a structure consisting of stacked quintuple layers. Single crystal surfaces are commonly prepared by mechanical cleaving. This work explores the use of low energy Ar+ ion bombardment and annealing (IBA) as an alternative method to produce reproducible and stable Bi2Se3 surfaces under ultra-high vacuum (UHV). It is found that a clean and well-ordered surface can be prepared by a single cycle of 1 keV Ar+ ion bombardment and 30 min of annealing. Low energy electron diffraction (LEED) and detailed low energy ion scattering (LEIS) measurements show no differences between IBA-prepared surfaces and those prepared by in situ cleaving in UHV. Analysis of the LEED patterns shows that the optimal annealing temperature is 450 °C. Angular LEIS scans reveal the formation of surface Se vacancies when the annealing temperature exceeds 520 °C.

Characterization and Evaluation of Ti-Zr-V Non-evaporable Getter Films Used in Vacuum Systems

NASA Astrophysics Data System (ADS)

Ferreira, M. J.; Seraphim, R. M.; Ramirez, A. J.; Tabacniks, M. H.; Nascente, P. A. P.

Among several methods used to obtain ultra-high vacuum (UHV) for particles accelerators chambers, it stands out the internal coating with metallic films capable of absorbing gases, called NEG (non-evaporable getter). Usually these materials are constituted by elements of great chemical reactivity and solubility (such as Ti, Zr, and V), at room temperature for oxygen and other gases typically found in UHV, such as H2, CO, and CO2. Gold and ternary Ti-Zr-V films were produced by magnetron sputtering, and their composition, structure, morphology, and aging characteristics were characterized by energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), field emission gun sc anning electronmicroscopy (FEG-SEM), atomic force microscopy (AFM), high resolution transmission electron microscopy (HRTEM). The comparison between the produced films and commercial samples indicated that the desirable characteristics depend on the nanometric structure of the films and that this structure is sensitive to the heat treatments.

Stoichiometric and Oxygen-Deficient VO2 as Versatile Hole Injection Electrode for Organic Semiconductors.

PubMed

Fu, Keke; Wang, Rongbin; Katase, Takayoshi; Ohta, Hiromichi; Koch, Norbert; Duhm, Steffen

2018-03-28

Using photoemission spectroscopy, we show that the surface electronic structure of VO 2 is determined by the temperature-dependent metal-insulator phase transition and the density of oxygen vacancies, which depends on the temperature and ultrahigh vacuum (UHV) conditions. The atomically clean and stoichiometric VO 2 surface is insulating at room temperature and features an ultrahigh work function of up to 6.7 eV. Heating in UHV just above the phase transition temperature induces the expected metallic phase, which goes in hand with the formation of oxygen defects (up to 6% in this study), but a high work function >6 eV is maintained. To demonstrate the suitability of VO 2 as hole injection contact for organic semiconductors, we investigated the energy-level alignment with the prototypical organic hole transport material N, N'-di(1-naphthyl)- N, N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (NPB). Evidence for strong Fermi-level pinning and the associated energy-level bending in NPB is found, rendering an Ohmic contact for holes.

An ultrahigh vacuum fast-scanning and variable temperature scanning tunneling microscope for large scale imaging.

PubMed

Diaconescu, Bogdan; Nenchev, Georgi; de la Figuera, Juan; Pohl, Karsten

2007-10-01

We describe the design and performance of a fast-scanning, variable temperature scanning tunneling microscope (STM) operating from 80 to 700 K in ultrahigh vacuum (UHV), which routinely achieves large scale atomically resolved imaging of compact metallic surfaces. An efficient in-vacuum vibration isolation and cryogenic system allows for no external vibration isolation of the UHV chamber. The design of the sample holder and STM head permits imaging of the same nanometer-size area of the sample before and after sample preparation outside the STM base. Refractory metal samples are frequently annealed up to 2000 K and their cooldown time from room temperature to 80 K is 15 min. The vertical resolution of the instrument was found to be about 2 pm at room temperature. The coarse motor design allows both translation and rotation of the scanner tube. The total scanning area is about 8 x 8 microm(2). The sample temperature can be adjusted by a few tens of degrees while scanning over the same sample area.

Energy characteristics of the CO2 laser cutting of thick steel sheets

NASA Astrophysics Data System (ADS)

Orishich, A. M.

2012-01-01

In the present paper the scaling laws for the oxygen-assisted laser cutting of low-carbon steel of 5-25 mm is studied experimentally. No dross and minimal roughness of the cut surface were chosen as criteria of quality. The paper also studies the possibility to describe the cutting process by the similarity method and as ratios between dimensionless variables. Normalized power W/ktT, normalized velocity Vcb/a (Peclet number) and kerf width have special optimum numb. Formulas were obtained to determine the optimum values of the laser power and cutting speed for the given sheet thickness. The energy balance of the oxygen-assisted laser cutting is studied experimentally at these optimum parameters. The absorbed laser energy, heat conduction losses and cut width were measured experimentally, and then the energy of exothermic reaction of oxidation was found from the balance equation. To define the integral coefficient of absorption, the laser power was measured on the cutting channel exit during the cutting. The heat conduction losses were measured by the calorimetric method. It has been established that the absorbed laser energy, oxidation energy, thermal losses and melting enthalpy related to a sheet thickness unit, do not depend on the sheet thickness at the cutting with the minimal roughness. The results enable to determine the fraction of the oxidized iron in the melt and thermal efficiency at the cutting with the minimal roughness. The share of the oxidation reaction energy is 50-60% in the total contributed energy.

The Big-Bubble Full Femtosecond Laser-Assisted Technique in Deep Anterior Lamellar Keratoplasty.

PubMed

Buzzonetti, Luca; Petrocelli, Gianni; Valente, Paola; Iarossi, Giancarlo; Ardia, Roberta; Petroni, Sergio; Parrilla, Rosa

2015-12-01

To describe the big-bubble full femtosecond laser-assisted (BBFF) technique, which could be helpful in standardizing the big-bubble technique in deep anterior lamellar keratoplasty (DALK). Ten eyes of 10 consecutive patients affected by keratoconus underwent the BBFF technique using the 150-kHz IntraLase femtosecond laser (Intra-Lase FS Laser; Abbott Medical Optics, Inc., Santa Ana, CA). A 9-mm diameter metal mask with a single fissure 0.7 mm wide oriented at the 12-o'clock position was positioned into the cone, over the laser glass. The laser performed a ring lamellar cut (internal diameter = 3 mm; external diameter = 8 mm) 100 µm above the thinnest point, with the photodisruption effectively occurring only in the corneal stroma corresponding to the fissure to create a deep stromal channel; subsequently, an anterior side cut created an arcuate incision, from the corneal surface to the deep stromal channel on the mask's opening site. The mask was removed and the laser performed a full lamellar cut 200 µm above the thinnest point to create a lamella. After the removal of the lamella, the air needle was inserted into the stromal channel and air was injected to achieve a big bubble. The big bubble was achieved in 9 eyes (all type 1 bubbles) and all procedures were completed as DALK. Preliminary results suggest that the BBFF technique could help in standardizing the big-bubble technique in DALK, reducing the "learning curve" for surgeons who approach this technique and the risks of intraoperative complications. Copyright 2015, SLACK Incorporated.

EEG monitoring of a free-swimming diver at a working depth of 15 meters.

NASA Technical Reports Server (NTRS)

Zweizig, J. R.; Adey, W. R.; Hanley, J.; Hahn, P. M.; Pilmanis, A. A.; Given, R. R.; Cockett, A. T. K.

1972-01-01

Feasibility has been shown for underwater transmission of physiological signals, using frequency modulation of carriers transmitted by return-current-density methods, as part of a personal biotelemetry system. In the prototype system, a standard IRIG subcarrier frequency (2300 Hz) was used. Power requirements, antenna design, and signal attenuation are compatible with free-ranging diving activity at distances up to 15 meters from the receiver. Extrapolation from this study and further developments are expected to substantially increase the range. Advantages of this system include subcarrier compatibility with standard IRIG demodulators using channels 1 through 10, the absence of highly specialized antenna requirements, and reasonable attenuation characteristics for transmission through the turbidity of typical seawater. Moreover, the system would not appear to be depth limited, and to be compatible with use of high-powered transponders of the same type for long-distance transmission, with or without further encoding.

Tachycardia-bradycardia syndrome: Electrophysiological mechanisms and future therapeutic approaches (Review)

PubMed Central

Tse, Gary; Liu, Tong; Li, Ka Hou Christien; Laxton, Victoria; Wong, Andy On-Tik; Chan, Yin Wah Fiona; Keung, Wendy; Chan, Camie W.Y.; Li, Ronald A.

2017-01-01

Sick sinus syndrome (SSS) encompasses a group of disorders whereby the heart is unable to perform its pacemaker function, due to genetic and acquired causes. Tachycardia-bradycardia syndrome (TBS) is a complication of SSS characterized by alternating tachycardia and bradycardia. Techniques such as genetic screening and molecular diagnostics together with the use of pre-clinical models have elucidated the electrophysiological mechanisms of this condition. Dysfunction of ion channels responsible for initiation or conduction of cardiac action potentials may underlie both bradycardia and tachycardia; bradycardia can also increase the risk of tachycardia, and vice versa. The mainstay treatment option for SSS is pacemaker implantation, an effective approach, but has disadvantages such as infection, limited battery life, dislodgement of leads and catheters to be permanently implanted in situ. Alternatives to electronic pacemakers are gene-based bio-artificial sinoatrial node and cell-based bio-artificial pacemakers, which are promising techniques whose long-term safety and efficacy need to be established. The aim of this article is to review the different ion channels involved in TBS, examine the three-way relationship between ion channel dysfunction, tachycardia and bradycardia in TBS and to consider its current and future therapies. PMID:28204831

Tachycardia-bradycardia syndrome: Electrophysiological mechanisms and future therapeutic approaches (Review).

PubMed

Tse, Gary; Liu, Tong; Li, Ka Hou Christien; Laxton, Victoria; Wong, Andy On-Tik; Chan, Yin Wah Fiona; Keung, Wendy; Chan, Camie W Y; Li, Ronald A

2017-03-01

Sick sinus syndrome (SSS) encompasses a group of disorders whereby the heart is unable to perform its pacemaker function, due to genetic and acquired causes. Tachycardia‑bradycardia syndrome (TBS) is a complication of SSS characterized by alternating tachycardia and bradycardia. Techniques such as genetic screening and molecular diagnostics together with the use of pre-clinical models have elucidated the electrophysiological mechanisms of this condition. Dysfunction of ion channels responsible for initiation or conduction of cardiac action potentials may underlie both bradycardia and tachycardia; bradycardia can also increase the risk of tachycardia, and vice versa. The mainstay treatment option for SSS is pacemaker implantation, an effective approach, but has disadvantages such as infection, limited battery life, dislodgement of leads and catheters to be permanently implanted in situ. Alternatives to electronic pacemakers are gene‑based bio‑artificial sinoatrial node and cell‑based bio‑artificial pacemakers, which are promising techniques whose long-term safety and efficacy need to be established. The aim of this article is to review the different ion channels involved in TBS, examine the three‑way relationship between ion channel dysfunction, tachycardia and bradycardia in TBS and to consider its current and future therapies.

Synthetic Ion Channels and DNA Logic Gates as Components of Molecular Robots.

PubMed

Kawano, Ryuji

2018-02-19

A molecular robot is a next-generation biochemical machine that imitates the actions of microorganisms. It is made of biomaterials such as DNA, proteins, and lipids. Three prerequisites have been proposed for the construction of such a robot: sensors, intelligence, and actuators. This Minireview focuses on recent research on synthetic ion channels and DNA computing technologies, which are viewed as potential candidate components of molecular robots. Synthetic ion channels, which are embedded in artificial cell membranes (lipid bilayers), sense ambient ions or chemicals and import them. These artificial sensors are useful components for molecular robots with bodies consisting of a lipid bilayer because they enable the interface between the inside and outside of the molecular robot to function as gates. After the signal molecules arrive inside the molecular robot, they can operate DNA logic gates, which perform computations. These functions will be integrated into the intelligence and sensor sections of molecular robots. Soon, these molecular machines will be able to be assembled to operate as a mass microrobot and play an active role in environmental monitoring and in vivo diagnosis or therapy. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Flood management on the lower Yellow River: hydrological and geomorphological perspectives

NASA Astrophysics Data System (ADS)

Shu, Li; Finlayson, Brian

1993-05-01

The Yellow River, known also as "China's Sorrow", has a long history of channel changes and disastrous floods in its lower reaches. Past channel positions can be identified from historical documentary records and geomorphological and sedimentological evidence. Since 1947, government policy has been aimed at containing the floods within artificial levees and preventing the river from changing its course. Flood control is based on flood-retarding dams and off-stream retention basins as well as artificial levees lining the channel. The design flood for the system has a recurrence interval of only around 60 years and floods of this and larger magnitudes can be generated downstream of the main flood control dams at Sanmenxia and Xiaolangdi. Rapid sedimentation along the river causes problems for storage and has raised the bed of the river some 10 m above the surrounding floodplain. The present management strategy is probably not viable in the long term and to avoid a major disaster a new management approach is required. The most viable option would appear to be to breach the levees at predetermined points coupled with advanced warning and evacuation of the population thus put at risk.

Cross-Layer Design for Video Transmission over Wireless Rician Slow-Fading Channels Using an Adaptive Multiresolution Modulation and Coding Scheme

NASA Astrophysics Data System (ADS)

Pei, Yong; Modestino, James W.

2007-12-01

We describe a multilayered video transport scheme for wireless channels capable of adapting to channel conditions in order to maximize end-to-end quality of service (QoS). This scheme combines a scalable H.263+ video source coder with unequal error protection (UEP) across layers. The UEP is achieved by employing different channel codes together with a multiresolution modulation approach to transport the different priority layers. Adaptivity to channel conditions is provided through a joint source-channel coding (JSCC) approach which attempts to jointly optimize the source and channel coding rates together with the modulation parameters to obtain the maximum achievable end-to-end QoS for the prevailing channel conditions. In this work, we model the wireless links as slow-fading Rician channel where the channel conditions can be described in terms of the channel signal-to-noise ratio (SNR) and the ratio of specular-to-diffuse energy[InlineEquation not available: see fulltext.]. The multiresolution modulation/coding scheme consists of binary rate-compatible punctured convolutional (RCPC) codes used together with nonuniform phase-shift keyed (PSK) signaling constellations. Results indicate that this adaptive JSCC scheme employing scalable video encoding together with a multiresolution modulation/coding approach leads to significant improvements in delivered video quality for specified channel conditions. In particular, the approach results in considerably improved graceful degradation properties for decreasing channel SNR.

Comparison of the Lag Screw Placements for the Treatment of Stable and Unstable Intertrochanteric Femoral Fractures regarding Trabecular Bone Failure.

PubMed

Celik, Talip; Mutlu, Ibrahim; Ozkan, Arif; Kisioglu, Yasin

2016-01-01

Background. In this study, the cut-out risk of Dynamic Hip Screw (DHS) was investigated in nine different positions of the lag screw for two fracture types by using Finite Element Analysis (FEA). Methods. Two types of fractures (31-A1.1 and A2.1 in AO classification) were generated in the femur model obtained from Computerized Tomography images. The DHS model was placed into the fractured femur model in nine different positions. Tip-Apex Distances were measured using SolidWorks. In FEA, the force applied to the femoral head was determined according to the maximum value being observed during walking. Results. The highest volume percentage exceeding the yield strength of trabecular bone was obtained in posterior-inferior region in both fracture types. The best placement region for the lag screw was found in the middle of both fracture types. There are compatible results between Tip-Apex Distances and the cut-out risk except for posterior-superior and superior region of 31-A2.1 fracture type. Conclusion. The position of the lag screw affects the risk of cut-out significantly. Also, Tip-Apex Distance is a good predictor of the cut-out risk. All in all, we can supposedly say that the density distribution of the trabecular bone is a more efficient factor compared to the positions of lag screw in the cut-out risk.