WorldWideScience
 
 
1

Water electrolysis: Divide and conquer  

Science.gov (United States)

The electrolysis of water provides a link between electrical energy and hydrogen, a high-energy-density fuel and a versatile energy carrier, but the process is expensive. Splitting the electrolysis reaction into two steps through an electrochemical 'buffer' offers a new way to think about improving the cost and efficiency of electrolysers.

Mallouk, Thomas E.

2013-05-01

2

Voltage Divider  

Science.gov (United States)

This voltage divider produces an output voltage, Vo, that is proportional to the input voltage, Vs. The output voltage is measured using a voltmeter. The input voltage is the voltage of the voltage source. The constant of proportionality is called the gain of the voltage divider. The value of the gain of the voltage divider is determined by the resistances, R1 and R2, of the two resistors that comprise the voltage divider.

2008-11-24

3

A high power water cooled resistor for the high voltage power supply in the TRIUMF RF system  

International Nuclear Information System (INIS)

The TRIUMF RF system high voltage power supply requires 0.5 ohm current limiting resistors to protect amplifier components during transients and crowbar operations. The crowbar typically causes a 16,000 amp transient pulse followed by a 4,000 amp current for 55 ms until the circuit breaker opens. The resulting stresses produced catastrophic failure of the original design within 100 crowbar cycles. A new resistor design has been developed to improve heat transfer characteristics and reduce current densities. Design changes were evaluated during extensive testing of a full scale model. The test results are reported with the resulting design described in detail

1993-05-17

4

Using Ohm's Law to Build a Voltage Divider  

Science.gov (United States)

In this activity, learners apply Ohmâs Law to construct voltage divider circuits. Learners discover how to read resistor codes and calculate resistor values. Using breadboards, learners build voltage dividers and predict and measure output voltage values. Learners are given the electrical requirements for an LED, and are then challenged to design and verify a voltage divider circuit to illuminate it.

Ieee

2014-05-23

5

Composition containing finely divided coal, water and at least one polyelectrolyte  

Energy Technology Data Exchange (ETDEWEB)

The invention concerns mixtures, mainly containing finely divided coal, water and polyelectrolyte. The mixture is characterized by containing 22-45% water by weight, and 0.01 - 5% polyelectrolyte with a mena molecular weight less than 5 times 10/sup 6/ - and which consists of water soluble, substituted polyethylene with sulphonate or hydrogensulphonate groups, which again are totally or partly in the form of salts, to the extent of a total sulphur content of 3 - 25% by weight, when the acidic groups are present as free acids.

Hansen, B.; Kelfve, S.; Mollberg, R.

1985-01-28

6

Resistor assemblies for NEC accelerators  

International Nuclear Information System (INIS)

Resistor assemblies have been under test in the 14UD Pelletron at the Australian National University in Canberra, Australia since February 1988, with no failures. A full set of resistors was installed in March 1989 and their performances has been satisfactory. The design incorporates coaxial shielding and individual mounting resulting in excellent flexibility in installation and maintenance. A pair of resistors is used to span each insulated gap. The design can be easily adapted to other types of accelerators. (orig.)

1990-02-01

7

High voltage load resistor array  

Energy Technology Data Exchange (ETDEWEB)

A high voltage resistor comprising an array of a plurality of parallel electrically connected resistor elements each containing a resistive solution, attached at each end thereof to an end plate, and about the circumference of each of the end plates, a corona reduction ring. Each of the resistor elements comprises an insulating tube having an electrode inserted into each end thereof and held in position by one or more hose clamps about the outer periphery of the insulating tube. According to a preferred embodiment, the electrode is fabricated from stainless steel and has a mushroom shape at one end, that inserted into the tube, and a flat end for engagement with the end plates that provides connection of the resistor array and with a load.

Lehmann, Monty Ray (Smithfield, VA)

2005-01-18

8

For current viewing resistor loads  

Science.gov (United States)

The invention comprises a terminal unit for a flat cable comprising a BNC-PCB connector having a pin for electrically contacting one or more conducting elements of a flat cable, and a current viewing resistor having an opening through which the pin extends and having a resistor face that abuts a connector face of the BNC-PCB connector, wherein the device is a terminal unit for the flat cable.

Lyons, Gregory R. (Tijeras, NM) [Tijeras, NM; Hass, Jay B. (Lee's Summit, MO) [Lee's Summit, MO

2011-04-19

9

UVA Virtual Lab: Resistor Waterwheel Analogy  

Science.gov (United States)

These pages provide a water model of an electrical circuit. In this case, the gerbil running in its wheel and the bucket pump are the equivalent of a battery. The water represents the electrons in the circuit. The height represents the voltage. The wheel represents the resistor. As the electrons fall from high to low, energy is available to do work. This model is part of the UVA Virtual Lab collection. This project is supported by grants from the National Science Foundation, the University of Virginia, IBM, and Discreet Corporation.

Bean, John

2010-12-23

10

Ground-water modeling of pumping effects near regional ground-water divides and river/aquifer systems - Results and implications of numerical experiments  

Science.gov (United States)

Agreements between United States governors and Canadian territorial premiers establish water-management principles and a framework for protecting Great Lakes waters, including ground water, from diversion and consumptive uses. The issue of ground-water diversions out of the Great Lakes Basin by large-scale pumping near the divides has been raised. Two scenario models, in which regional ground-water flow models represent major aquifers in the Great Lakes region, were used to assess the effect of pumping near ground-water divides. The regional carbonate aquifer model was a generalized model representing northwestern Ohio and northeastern Indiana; the regional sandstone aquifer model used an existing calibrated ground-water flow model for southeastern Wisconsin. Various well locations and pumping rates were examined. Although the two models have different frameworks and boundary conditions, results of the models were similar. There was significant diversion of ground water across ground-water divides due to pumping within 10 miles of the divides. In the regional carbonate aquifer model, the percentage of pumped water crossing the divide ranges from about 20 percent for a well 10 miles from the divide to about 50 percent for a well adjacent to the divide. In the regional sandstone aquifer model, the percentages range from about 30 percent for a well 10 miles from the divide to about 50 percent for a well adjacent to the divide; when pumping on the west side of the divide, within 5 mi of the predevelopment divide, results in at least 10 percent of the water being diverted from the east side of the divide. Two additional scenario models were done to examine the effects of pumping near rivers. Transient models were used to simulate a rapid stage rise in a river during pumping at a well in carbonate and glacial aquifers near the river. Results of water-budget analyses indicate that induced infiltration, captured streamflow, and underflow were important for both glacial and carbonate aquifers; however, in many cases, traveltimes from the river to the well will limit river water from physically entering the well.

Sheets, Rodney A.; Dumouchelle, Denise H.; Feinstein, Daniel T.

2005-01-01

11

DIGITAL DIVIDE  

Directory of Open Access Journals (Sweden)

Full Text Available The digital divide refers to the gap between people with effective access todigital and information technology and those with very limited or no access at all. Itincludes the imbalance both in physical access to technology and the resources and skillsneeded to effectively participate as a digital citizen. Knowledge divide reflects the accessof various social groupings to information and knowledge, typically gender, income,race, and by location. The term global digital divide refers to differences in accessbetween countries.

SANTOSH GOBRU JADHAO

2013-02-01

12

Silicon thermal conductivity detector (TCD) with the Pt resistors  

Science.gov (United States)

Pt resistors formation technology for the thermal conductivity detector (TCD) is presented. Channels for the gas flow were milled in the glass plate and etched in the silicon chip with use of the TMAH+ water solution. Resistors made up of the thin Pt layer, were located across the channels on the silicon chips. They were connected through the contract windows in the Si3N4 and SiO2 layers, with the n+-type regions of the p-type, (100) silicon substrate substrate. BSC-type contacts to the bonding pads allowed electrical contact to the bonding pads located on the opposite side of the silicon substrate. Resistors were electrically tested as a detector heaters and thermoresistors.

Lysko, Jan M.; Gorska, Marianna; Wrzesinska, Hanna; Hejduk, Krzysztof; Latecki, Bogdan; Lozinko, Joanna

2003-09-01

13

Characterization of interdigitated electrode structures for water contaminant detection using a hybrid voltage divider and a vector network analyzer.  

Science.gov (United States)

Interdigitated capacitive electrode structures have been used to monitor or actuate over organic and electrochemical media in efforts to characterize biochemical properties. This article describes a method to perform a pre-characterization of interdigitated electrode structures using two methods: a hybrid voltage divider (HVD) and a vector network analyzer (VNA). Both methodologies develop some tests under two different conditions: free air and bi-distilled water media. Also, the HVD methodology is used for other two conditions: phosphate buffer with laccase (polyphenoloxidase; EC 1.10.3.2) and contaminated media composed by a mix of phosphate buffer and 3-ethylbenzothiazoline-6-sulfonic acid (ABTS). The purpose of this study is to develop and validate a characterization methodology using both, a hybrid voltage divider and VNA T-# network impedance models of the interdigitated capacitive electrode structure that will provide a shunt RC network of particular interest in detecting the amount of contamination existing in the water solution for the media conditions. This methodology should provide us with the best possible sensitivity in monitoring water contaminant media characteristics. The results show that both methods, the hybrid voltage divider and the VNA methodology, are feasible in determining impedance modeling parameters. These parameters can be used to develop electric interrogation procedures and devices such as dielectric characteristics to identify contaminant substances in water solutions. PMID:23365953

Rodríguez-Delgado, José Manuel; Rodríguez-Delgado, Melissa Marlene; Mendoza-Buenrostro, Christian; Dieck-Assad, Graciano; Omar Martínez-Chapa, Sergio

2012-01-01

14

Research on voltage-divider of PMT applied to GRD  

International Nuclear Information System (INIS)

A transistor voltage divider is designed to decrease the dead time owing to large signal, and to satisfy the requirement of GRB detection. The simulation and experiment prove that the recovery time of the PMT working in the control of the transistor voltage divider is an order of magnitude smaller than the conventional resistor-capacitor voltage divider. (authors)

2010-04-01

15

Thermal aspects of resistors embedded in dielectrics  

Energy Technology Data Exchange (ETDEWEB)

This note presents a formula for estimating the temperature of a distributed resistor or resistor chain that is immersed in a dielectric medium, which in turn is surrounded by a heat reservoir. An example computation from an actual instrument in included. 6 refs.

Caprari, R.S.

1995-10-01

16

Thermal aspects of resistors embedded in dielectrics  

International Nuclear Information System (INIS)

This note presents a formula for estimating the temperature of a distributed resistor or resistor chain that is immersed in a dielectric medium, which in turn is surrounded by a heat reservoir. An example computation from an actual instrument in included. 6 refs

1995-01-01

17

Software Development in the Water Sciences: a view from the divide (Invited)  

Science.gov (United States)

While training in statistical methods is an important part of many earth scientists' training, these scientists often learn the bulk of their software development skills in an ad hoc, just-in-time manner. Yet to carry out contemporary research scientists are spending more and more time developing software. Here I present perspectives - as an earth sciences graduate student with professional software engineering experience - on the challenges scientists face adopting software engineering practices, with an emphasis on areas of the science software development lifecycle that could benefit most from improved engineering. This work builds on experience gained as part of the NSF-funded Water Science Software Institute (WSSI) conceptualization award (NSF Award # 1216817). Throughout 2013, the WSSI team held a series of software scoping and development sprints with the goals of: (1) adding features to better model green infrastructure within the Regional Hydro-Ecological Simulation System (RHESSys); and (2) infusing test-driven agile software development practices into the processes employed by the RHESSys team. The goal of efforts such as the WSSI is to ensure that investments by current and future scientists in software engineering training will enable transformative science by improving both scientific reproducibility and researcher productivity. Experience with the WSSI indicates: (1) the potential for achieving this goal; and (2) while scientists are willing to adopt some software engineering practices, transformative science will require continued collaboration between domain scientists and cyberinfrastructure experts for the foreseeable future.

Miles, B.; Band, L. E.

2013-12-01

18

Continental divide  

International Nuclear Information System (INIS)

The historical precedents to the idea of continent-wide diversion of water in North America are reviewed, starting from early perceptions of continental drainage and the era of canal building that reached its peak in the mid-1800s. The attitude that natural landscapes can be rearranged to suit human needs has persisted from that era with the proposal for continent-wide water diversion megaprojects, many involving the movement of water from Canada to the southwestern USA. Over 50 water diversions exist in Canada, with a total diverted flow of 4,400 m3/s. The density of interconnected and almost-connected lakes and rivers has favored such diversions. Of these diversions, 95% of their storage capacity and 96% of their flow is for hydroelectric power generation. The number of diversions in the USA is similar but water volumes are only a sixth of those in Canada, and the water is mainly used for irrigation or water supply. Experience in both countries shows that diversions are contained by political boundaries. No large-scale diversion of fresh water across the international boundary has received any government support, and no significant change in this policy is anticipated. In the water-short areas of the USA, conservation and reallocation of water resources are receiving priority. 19 refs., 2 figs., 2 tabs

1991-03-12

19

Moebius resistor is noninductive and nonreactive  

Science.gov (United States)

Moebius strip made of insulated resistive materials with electrical leads attached directly opposite one another provides a noninductive, nonreactive resistor which is simple, inexpensive, and flexible in usage, and can be made to almost any desired size and shape.

Davis, R. L.

1968-01-01

20

Liquid resistor for protecting superconducting coil  

International Nuclear Information System (INIS)

The present invention concerns a protective resistor for attenuating electric current in superconducting coils when they are quenched (normal conduction state) in an external electric circuit of DC-excited immersion cooling-type superconducting coils for use in a thermonuclear device. Namely, the resistor of the present invention has an anode disposed on one side and a cathode disposed on the other side at a predetermined distance. Both of the electrodes are connected by means of a channel having a small cross section. The channel is filled with an electrolyte to form a battery, which constitutes a resistor. This is connected in parallel with superconducting coils of the electric circuit of the immersion cooling-type superconducting coils. Such a protective liquid resistor does not cause bubbling at an electrode plate although DC current is used. In addition, the electrolyte has a characteristic of increasing the conductivity along with temperature elevation. Accordingly, it provides an effect of improving the safety factor of the minimum pressure resistance of the immersion cooling-type superconductive coils compared with a constant resistor or a metal resistor. The safety factor of pressure resistance can be improved with no change in the design of the superconducting coils. (I.S.)

1994-03-01

 
 
 
 
21

Design of a Compact Dump Resistor System for LCD Magnet  

CERN Multimedia

In this technical note we suggest a possible solution for the choice of the detector magnet dump resistor. The push-pull scenario for Linear Collider Detectors imposes new solutions for magnet powering and protection lines, else than what developed for LHC detectors. The magnet dump resistor is the protecting equipment that has the function of extracting a significant amount of magnetic stored energy, from the coil winding to a dump. The LCD magnet has to move with the experiment from the garage to the beam position, so it has to be compact and reliable at the same time. We make here a proposal for a passive water-cooled dumper, we calculate the minimum amount of water required, the resistor hot-spot temperature, the overall mechanical design. The electrical part is not covered by this note, as it can be assumed that the solutions adopted by LHC detector magnets, in terms of quench instrumentation, energy extraction and maximum voltage, are not significantly affected by the push-pull scenario.

Gaddi, A

2010-01-01

22

Perturbation of infinite networks of resistors  

CERN Multimedia

The resistance between arbitrary nodes of infinite networks of resistors is studied when the network is perturbed by removing one bond from the perfect lattice. A connection is made between the resistance and the lattice Green's function of the perturbed network. Solving Dyson's equation the Green's function and the resistance of the perturbed lattice are expressed in terms of those of the perfect lattice. Numerical results are presented for a square lattice. Our method of the lattice Green's function in studying resistor networks can also be applied in the field of random walks as well as electrical and mechanical breakdown phenomena in insulators, thin films and modern ceramics.

Cserti, J; Piróth, A; Pir\\'oth, Attila

2001-01-01

23

Ionization monitor with improved ultra-high megohm resistor  

Energy Technology Data Exchange (ETDEWEB)

An ionization monitor measures extremely small currents using a resistor containing a beta emitter to generate ion-pairs which are collected as current when the device is used as a feedback resistor in an electrometer circuit. By varying the amount of beta emitter, the resistance of the resistor may be varied.

Burgess, Edward T. (Carlisle, OH)

1988-11-05

24

Ionization monitor with improved ultra-high megohm resistor  

Energy Technology Data Exchange (ETDEWEB)

An ionization monitor measures extremely small currents using a resistor containing a beta emitter to generate ion-pairs which are collected as current when the device is used as a feedback resistor in an electrometer circuit. By varying the amount of beta emitter, the resistance of the resistor may be varied. 5 figs.

Burgess, E T

1986-10-07

25

FGMOS Based Voltage-Controlled Grounded Resistor  

Directory of Open Access Journals (Sweden)

Full Text Available This paper proposes a new floating gate MOSFET (FGMOS based voltage-controlled grounded resistor. In the proposed circuit FGMOS operating in the ohmic region is linearized by another conventional MOSFET operating in the saturation region. The major advantages of FGMOS based voltage-controlled grounded resistor (FGVCGR are simplicity, low total harmonic distortion (THD, and low power consumption. A simple application of this FGVCGR as a tunable high-pass filter is also suggested. The proposed circuits operate at the supply voltages of +/-0.75 V. The circuits are designed and simulated using SPICE in 0.25-µm CMOS technology. The simulation results of FGVCGR demonstrate a THD of 0.28% for the input signal 0.32 Vpp at 45 kHz, and a maximum power consumption of 254 µW.

R. Pandey

2010-09-01

26

Zinc oxide varistors and/or resistors  

Energy Technology Data Exchange (ETDEWEB)

Varistors and/or resistors are described that include doped zinc oxide gel microspheres. The doped zinc oxide gel microspheres preferably have from about 60 to about 95% by weight zinc oxide and from about 5 to about 40% by weight dopants based on the weight of the zinc oxide. The dopants are a plurality of dopants selected from silver salts, boron oxide, silicon oxide and hydrons oxides of aluminum, bismuth, cobalt, chromium, manganese, nickel, and antimony.

Arnold, W.D. Jr.; Bond, W.D.; Lauf, R.J.

1993-07-27

27

Renormalized field theory of resistor diode percolation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We study resistor diode percolation at the transition from the non-percolating to the directed percolating phase. We derive a field theoretic Hamiltonian which describes not only geometric aspects of directed percolation clusters but also their electric transport properties. By employing renormalization group methods we determine the average two-port resistance of critical clusters, which is governed by a resistance exponent $\\phi$. We calculate $\\phi$ to two-loop order.

Stenull, Olaf; Janssen, Hans-karl

2001-01-01

28

Perturbation theory of uniform tiling of space with resistors  

Science.gov (United States)

Using the general Green method, the resistance between two arbitrary nodes of any resistor network structure, which is a periodic (uniform) tiling of d -dimensional space with electrical resistors, is studied when the network is perturbed by replacing one edge (resistor) by another one. The analytical expression of the resistance for perturbed lattice in terms of that for the perfect one is derived. Theoretical results are presented for the infinite perturbed centered square lattice. In addition, these results are verified experimentally and numerically.

Owaidat, M. Q.; Hijjawi, R. S.; Khalifeh, J. M.

2014-02-01

29

Modeling of three-dimensional diffusible resistors with the one-dimensional tube multiplexing method  

International Nuclear Information System (INIS)

Electronic-behavior modeling of three-dimensional (3D) p+-?-p+ and n+-?-n+ semiconducting diffusible devices with highly accurate resistances for the design of analog resistors, which are compatible with the CMOS (complementary-metal-oxide-semiconductor) technologies, is performed in three dimensions with the fast tube multiplexing method (TMM). The current–voltage (I–V) curve of a silicon device is usually computed with traditional device simulators of technology computer-aided design (TCAD) based on the finite-element method (FEM). However, for the design of 3D p+-?-p+ and n+-?-n+ diffusible resistors, they show a high computational cost and convergence that may fail with fully non-separable 3D dopant concentration profiles as observed in many diffusible resistors resulting from laser trimming. These problems are avoided with the proposed TMM, which divides the 3D resistor into one-dimensional (1D) thin tubes with longitudinal axes following the main orientation of the average electrical field in the tubes. The I–V curve is rapidly obtained for a device with a realistic 3D dopant profile, since a system of three first-order ordinary differential equations has to be solved for each 1D multiplexed tube with the TMM instead of three second-order partial differential equations in the traditional TCADs. Simulations with the TMM are successfully compared to experimental results from silicon-based 3D resistors fabricated by laser-induced dopant diffusion in the gaps of MOSFETs (metal-oxide-semiconductor field-effect transistors) without initial gate. Using thin tubes with other shapes than parallelepipeds as ring segments with toroidal lateral surfaces, the TMM can be generalized to electronic devices with other types of 3D diffusible microstructures

2009-09-01

30

Resistor Loaded EBG Surfaces for Slot Antenna Design  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present a resistor loaded EBG surface (REBG) for antenna design. Specifically, lumped resistors are embedded between periodic metal patches of mushroom like EBG structures. Surface wave propagation along the REBG surface is analyzed as a periodically loaded transmission line model and low transmission bandgap is identified and experimen

Shenyi Cao; Yunqi Fu

2013-01-01

31

A high Tc superconducting loss-free resistor  

International Nuclear Information System (INIS)

Full text: A loss-less resistor (LLR) is introduced as a novel concept with consideration of using a high Tc superconducting (HTS) inductor. This LLR resistor mainly consists of an electronic switch bridge and a inductor L. By controlling the electronic switch bridge, an equivalent resistance R(i) can be generated, and its value is R(i) = (L/i)di/dt, which allows the LLR resistor have a resistive voltage-current characteristic i.e. V(t) = i(t)R, but without thermal loss across this LLR resistor if a superconducting inductor is selected. With a HTS winding and therefore a HTS inductor, this LLR resistor is practically close to loss-free. The LLR resistor can be widely used to replace the conventional resistor in order to save energy and to improve performance of the systems. The HTS wires are identified for this application, by considering their critical currents, ac loss and possibility to make a large HTS inductor winding. To make LLR resistors for practical applications is considered with the existing HTS wires

1996-02-02

32

The Sponge Resistor Model — A Hydrodynamic Analog to Illustrate Ohm's Law, the Resistor Equation R =??/A, and Resistors in Series and Parallel  

Science.gov (United States)

Physics students encountering electric circuits for the first time often ask why adding more resistors to a circuit sometimes increases and sometimes decreases the resulting total resistance. It appears that these students have an inadequate understanding of current flow and resistance. Students who do not adopt a model of current, voltage, and resistance necessarily resort to memorizing formulas for calculating, e.g., the resistance of a resistor network. For these students, certain properties of electric circuits may remain mysterious or puzzling.

Pfister, Hans

2014-05-01

33

Experimental Research on Properties of Materials of Grounding Resistor  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, we have a experimental research on properties of materials of grounding resistor. Experiment test of the grounding resistor in the state of analog ground fault have been done, the performance parameters on the mechanics, thermal and electrical of alloy materials with different kinds and different specification have been got. The performance and its character of alloy materials have been grasped in the state of analog ground fault by analysis and processing. The research results have an important significance on the material selection and structure design of low resistance grounding resistor.

He Da-Jiang

2013-03-01

34

Room-temperature antiferromagnetic memory resistor  

Science.gov (United States)

The bistability of ordered spin states in ferromagnets provides the basis for magnetic memory functionality. The latest generation of magnetic random access memories rely on an efficient approach in which magnetic fields are replaced by electrical means for writing and reading the information in ferromagnets. This concept may eventually reduce the sensitivity of ferromagnets to magnetic field perturbations to being a weakness for data retention and the ferromagnetic stray fields to an obstacle for high-density memory integration. Here we report a room-temperature bistable antiferromagnetic (AFM) memory that produces negligible stray fields and is insensitive to strong magnetic fields. We use a resistor made of a FeRh AFM, which orders ferromagnetically roughly 100 K above room temperature, and therefore allows us to set different collective directions for the Fe moments by applied magnetic field. On cooling to room temperature, AFM order sets in with the direction of the AFM moments predetermined by the field and moment direction in the high-temperature ferromagnetic state. For electrical reading, we use an AFM analogue of the anisotropic magnetoresistance. Our microscopic theory modelling confirms that this archetypical spintronic effect, discovered more than 150 years ago in ferromagnets, is also present in AFMs. Our work demonstrates the feasibility of fabricating room-temperature spintronic memories with AFMs, which in turn expands the base of available magnetic materials for devices with properties that cannot be achieved with ferromagnets.

Marti, X.; Fina, I.; Frontera, C.; Liu, Jian; Wadley, P.; He, Q.; Paull, R. J.; Clarkson, J. D.; Kudrnovský, J.; Turek, I.; Kuneš, J.; Yi, D.; Chu, J.-H.; Nelson, C. T.; You, L.; Arenholz, E.; Salahuddin, S.; Fontcuberta, J.; Jungwirth, T.; Ramesh, R.

2014-04-01

35

Two types of photomultiplier voltage dividers for high and changing count rates  

International Nuclear Information System (INIS)

We report on the design of two types of voltage distribution circuits for high stability photomultiplier operation. 'Type A' voltage divider is an ohmic voltage divider with high bleeder current (up to 10 mA) and the resistor chain split at one of the last dynodes, usually the dynode where the analog signal is derived from. This simple constructive measure improves the stability of the dynode voltage by a factor of 5 compared with an unsplit conventional resistor chain. 'Type B' is a novel active voltage divider using cold cathode tubes ar regulating elements. This voltage divider exhibits excellent temperature stability (about 10-4/0C). With 'type B' an equal stability compared with conventional ohmic dividers can be achieved at a bleeder current smaller by one order of magnitude. Of course both concepts, 'type A' and 'type B', can be combined. (orig.)

1980-01-01

36

Novel charge sensitive preamplifier without high-value feedback resistor  

International Nuclear Information System (INIS)

A novel charge sensitive preamplifier is introduced. The method of removing the high value feedback resistor, the circuit design and analysis are described. A practical circuit and its measured performances are provided

1992-09-01

37

Direct-Write Precision Resistors for Ceramic Packages  

Energy Technology Data Exchange (ETDEWEB)

A direct-write approach to f abricate high precision resistors is reported. Special attention is paid to the effect of print thickrw;s on the resistance value of buried resistors after a low temperature co-firing process. The results show that the direct-write approach provides a superior line definition and thickness control over a traditional screen printing process. Microstructural analysis indicates that there is an interdiffused layer developed between the resistor material and the low temperature co-fired ceramic substrate. These observations are consistent with electrical IIH.SUKHIlentS which show that resistance increases as the effective cross-sectional area is reduced. Th: resistance data show that the standard deviations for resistors printed on a 6" x 6" area are 59Z0 and 15$Z0 for the direct-write and the screen-printed patterns, respectively.

Dai, S.; Dimos, D.; Huang, R.F.; Rodriguez, M.A.; Wilcox, D.; Yang, P.

1998-11-30

38

Dynamic Systems Model for Filamentary Mem-Resistors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A dynamic systems model is proposed describing memory resistors which include a filament conductive bridge. In this model the system state is defined by both a dynamic tunneling barrier (associated with the filament-electrode gap) and a dynamic Schottky barrier (associated with the electron depletion width surrounding the filament-electrode gap). A general model is formulated which may be applicable to many different forms of memory resistor materials. The frequency response...

Mouttet, Blaise

2011-01-01

39

Cooling process of the LHC energy extraction resistors  

CERN Document Server

The energy stored in all the LHC dipoles, about 11 GJ, can potentially cause severe damage to the magnets, bus bars and current leads. In order to protect the superconducting elements after a resistive transition, the energy is dissipated into dump resistors switched in series with the magnet chains. This paper describes the cooling process of the resistors and explains the choice process for the main components of the cooling equipment.

Peón-Hernández, G; Coelingh, G J; CERN. Geneva. ST Division

2003-01-01

40

OBIC analysis of stressed, thermally-isolated polysilicon resistors  

Energy Technology Data Exchange (ETDEWEB)

High gain Optical Beam Induced Current (OBIC) imaging has been used for the first time to examine the internal structural effects of electrical stress on thermally-isolated polysilicon resistors. The resistors are examined over a wide range of current densities, producing Joule heating up to {approximately}1200{degrees}C. Throughout this current density range, the OBIC images indicate a clustering of dopant under dc stress and a more uniform distribution under ac conditions. The OBIC images also reveal areas that are precursors to catastrophic resistor failure. In addition to OBIC imaging, conventional electrical measurements were performed, examining the polysilicon resistance degradation and time-to-failure as a function of electrical stress. The electrical measurements show a monotonic increase in polysilicon resistor lifetime with frequency (up to 2 kHz) when subjected to a bipolar ac stress. The enhanced lifetime was observed even under high temperature (from Joule heating) stress conditions previously reported to be electromigration-free. The dopant redistribution indicated by the OBIC images is consistent with an electromigration stress experienced by the polysilicon resistors. The implications for thermally-isolated polysilicon resistor reliability are examined briefly.

Cole, E.I. Jr.; Peterson, K.A.; Campbell, A.N.; Snyder, E.S.; Pierce, D.G. [Sandia National Labs., Albuquerque, NM (United States); Suehle, J.S. [National Inst. of Standards and Technology, Gaithersburg, MD (United States); Chaparala, P. [Maryland Univ., College Park, MD (United States)

1994-12-31

 
 
 
 
41

An air-cooled gradient resistor column for the KFUPM 350 kV ion accelerator  

International Nuclear Information System (INIS)

An air-cooled gradient resistor column has been designed and implemented for the KFUPM 350 kV ion accelerator. The air-cooled column overcomes operational limitations on the acceleration voltages obtained with the old water-cooled column and improves on reliability and maintainability. The new column consists of five sections, each having sixteen 8 M? 15 W resistors connected in a series-parallel combination. Corona shields defining equipotential circular planes have been incorporated to maintain a uniform potential difference across the column sections. In order to protect the gradient column and accelerator tube against arcing, spark gaps are provided on each corona shield. The new column has been tested over the full range of 0-320 kV across the accelerator tube for extended durations without arcing. Both electrical and mechanical aspects of the new design are discussed, measurement techniques used during installation and testing are described, and performance data are given. (orig.)

1996-08-21

42

A 83 GHz InP DHBT static frequency divider  

Science.gov (United States)

A static frequency divider is presented using 0.7 ?m InP DHBTs with 280 GHz ft/fmax. The divider is based on ECL master–slave D-flip–flop topology with 30 HBTs and 20 resistors with a chip size 0.62 × 0.65 mm2. The circuits use peaking inductance as a part of the loads to maximize the highest clock rate. Momentum simulation is used to accurately characterize the effect of the clock feedback lines at the W band. Test results show that the divider can operate from 1 GHz up to 83 GHz. Its phase noise is 139 dBc/Hz with 100 kHz offset. The power dissipation of divider core is 350 mW.

Youtao, Zhang; Xiaopeng, Li; Min, Zhang; Wei, Cheng; Xinyu, Chen

2014-04-01

43

Noise characteristics of resistors buried in low-temperature co-fired ceramics  

CERN Document Server

The comparison of noise properties of conventional thick film resistors prepared on alumina substrates and resistors embedded in low-temperature co-fired ceramics (LTCCs) is presented. Both types of resistors were prepared from commercially available resistive inks. Noise measurements of LTCC resistors below 1 kHz show Gaussian 1/f noise. This is concluded from the calculations of the second spectra as well as from studying the volume dependence of noise intensity. It has occurred that noise index of LTCC resistors on average is not worse than that of conventional resistors. A detailed study of co-fired surface resistors and co-fired buried resistors show that burying a resistor within LTCC substrate usually leads to (significant) enhancement of resistance but not of noise intensity. We interpret this behaviour as another argument in favour of tunnelling as the dominant conduction mechanism in LTCC resistors.

Kolek, A; Dziedzic, A

2003-01-01

44

RF and DC Power Handling Characterization of Thin Film Resistors Embedded on LCP  

Science.gov (United States)

For the first time, the DC and RF power handling capability of NiCrAlSi thin film resistors on Liquid Crystal Polymer (LCP) is presented. It is shown that there is a maximum power that the resistors can handle without causing degradation of the resistors, and this value is significantly less than the power required for burn out of the resistors. EDAX shows that the resistors fail due to electromigration of Ni and Cr, and migration of C from the LCP.

Ponchak, George E.; Jordan, Jennifer L.; Horst, Stephen; Papapolymerou, John

2007-01-01

45

The Open Access Divide  

Directory of Open Access Journals (Sweden)

Full Text Available This paper is an attempt to review various aspects of the open access divide regarding the difference between those academics who support free sharing of data and scholarly output and those academics who do not. It provides a structured description by adopting the Ws doctrines emphasizing such questions as who, what, when, where and why for information-gathering. Using measurable variables to define a common expression of the open access divide, this study collects aggregated data from existing open access as well as non-open access publications including journal articles and extensive reports. The definition of the open access divide is integrated into the discussion of scholarship on a larger scale.

Jingfeng Xia

2013-10-01

46

The nondeterministic divide  

Science.gov (United States)

The nondeterministic divide partitions a vector into two non-empty slices by allowing the point of division to be chosen nondeterministically. Support for high-level divide-and-conquer programming provided by the nondeterministic divide is investigated. A diva algorithm is a recursive divide-and-conquer sequential algorithm on one or more vectors of the same range, whose division point for a new pair of recursive calls is chosen nondeterministically before any computation is performed and whose recursive calls are made immediately after the choice of division point; also, access to vector components is only permitted during activations in which the vector parameters have unit length. The notion of diva algorithm is formulated precisely as a diva call, a restricted call on a sequential procedure. Diva calls are proven to be intimately related to associativity. Numerous applications of diva calls are given and strategies are described for translating a diva call into code for a variety of parallel computers. Thus diva algorithms separate logical correctness concerns from implementation concerns.

Charlesworth, Arthur

1990-01-01

47

Electrochemical Migration on Electronic Chip Resistors in Chloride Environments  

DEFF Research Database (Denmark)

Electrochemical migration behavior of end terminals on ceramic chip resistors (CCRs) was studied using a novel experimental setup in varying sodium chloride concentrations from 0 to 1000 ppm. The chip resistor used for the investigation was 10-kΩ CCR size 0805 with end terminals made of 97Sn3Pb alloy. Anodic polarization behavior of the electrode materials was investigated using a microelectrochemical setup. Material makeup of the chip resistor was investigated using scanning electron microscopy (SEM)/energy dispersive spectroscopy and focused-ion-beam SEM. Results showed that the dissolution rate of the Sn and stability of Sn ions in the solution layer play a significant role in the formation of dendrites, which is controlled by chloride concentration and potential bias. Morphology, composition, and resistance of the dendrites were dependent on chloride concentration and potential.

Minzari, Daniel; Jellesen, Morten Stendahl

2009-01-01

48

Ti-Cr-Al-O Thin Film Resistors  

Energy Technology Data Exchange (ETDEWEB)

Thin films of Ti-Cr-Al-O are produced for use as an electrical resistor material. The films are rf sputter deposited from ceramic targets using a reactive working gas mixture of Ar and O{sub 2}. Vertical resistivity values from 10{sup 4} to 10{sup 10} Ohm-cm are measured for Ti-Cr-Al-O films. The film resistivity can be design selected through control of the target composition and the deposition parameters. The Ti-Cr-Al-O thin film resistor is found to be thermally stable unlike other metal-oxide films.

Jankowski, A F; Hayes, J P

2002-03-21

49

Ruthenium oxide resistors as sensitive elements of composite bolometers  

International Nuclear Information System (INIS)

Bolometers for particle detection made with Ruthenium oxide thermistors could be produced by means of a simple technique on a variety of different materials as substrata. Preliminary results on alpha particle detection with devices realized using commercial RuO2 thick film resistor (Tfr) are considered positive for devices operating between. 3 and .1 k and determined us to pursue further the idea. Ruthenium oxide resistors on sapphire at the moment are being prepared. The behaviour of these devices st temperatures lower than .1 k has to be investigated in more detail

1988-01-01

50

Resistor Loaded EBG Surfaces for Slot Antenna Design  

Directory of Open Access Journals (Sweden)

Full Text Available We present a resistor loaded EBG surface (REBG for antenna design. Specifically, lumped resistors are embedded between periodic metal patches of mushroom like EBG structures. Surface wave propagation along the REBG surface is analyzed as a periodically loaded transmission line model and low transmission bandgap is identified and experimentally verified. The reflection properties of REBG surface to the incident electromagnetic waves are also studied. Slot antenna is placed within the REBG surface. The REBG surface is used to suppress surface waves across the antenna aperture, resulting in radiation performance improvement. Concurrently, the REBG surface can also absorb electromagnetic energy to reduce antenna radar cross section (RCS.

Shenyi Cao

2013-07-01

51

Divided-pulse lasers.  

Science.gov (United States)

We demonstrate the use of coherent division and recombination of the pulse within an ultrafast laser cavity to manage the nonlinear phase accumulation and scale the output pulse energy. We implement the divided-pulse technique in an ytterbium-doped fiber laser and achieve 16 times scaling of the pulse energy, to generate 6 nJ and 1.4 ps solitons in single-mode fiber. Potential extensions of this concept are discussed. PMID:24784100

Lamb, Erin S; Wright, Logan G; Wise, Frank W

2014-05-01

52

Divided-Pulse Lasers  

Science.gov (United States)

We demonstrate the use of coherent division and recombination of the pulse within an ultrafast laser cavity to manage the nonlinear phase accumulation and scale the output pulse energy. We implement the divided-pulse technique in an ytterbium-doped fiber laser and achieve 16-times scaling of the pulse energy, to generate 6 nJ and 1.4 ps solitons in single mode fiber. Potential extensions of this concept are discussed.

Lamb, Erin S.; Wright, Logan G.; Wise, Frank W.

2014-01-01

53

Air-cooled fast discharge resistors for ITER magnets  

International Nuclear Information System (INIS)

The ITER superconducting magnets will store up to 50 GJ of magnetic energy per operation cycle. In case of coil quench the energy stored in the coils must be extracted rapidly with a time constant from 7.5 to 14 s. It will be achieved by fast discharge resistors (FDR) normally bridged by circuit breakers and inserted in series with the superconducting coils. The fast discharge of the coils results practically in adiabatic heating of the resistive elements up to 200-300 deg. C. The resistors need to be cooled to the initial temperature over 6-8 h. Natural air circulation is proposed as a cooling method. In order to simulate the temperature response of the resistors to energy released in the resistive plates and to demonstrate their cooling capability within the required time by natural air circulation the numerical model of the resistor cooling circuit has been developed. As the calculations have shown, the developed FDR cooling system based on cooling by natural air circulation is capable of providing the required temperature operation regime of FDRs, but the supply channels are to be optimized so that the cooling time does not exceed the permissible one.

2011-10-01

54

Series fault limiting resistors for Atlas Marx modules  

Energy Technology Data Exchange (ETDEWEB)

The proposed Atlas design provides a current pulse to the experiment chamber from a set of 20, 3-Marx-unit-wide modules radially positioned around a retangular disk transmission-line system (total of 60 Marxes in parallel){sup 1}. The Atlas circuit is designed to be near-critically-damped network with a total erected capacitance of 200 {mu}F at 600 KV. The justification for the necessary circuit resistance in this approach is based on reliability, fault tolerance and operational maintenance{sup 1}. Also the use of high energy- density capacitors that have lower tolerance to voltage reversal is a primary reason for the damping provided by significant series resistance. To obtain the damping there are two system resistors in the Atlas design. One resistor is a shunt element designed to damp the resonance caused by the relatively high-Q disk transmission-line capacitance and the Marx bank inductance. The second, more significant resistor is a series, fault-current limiting element that also performs the necessary damping for voltage reversal at the bank capacitors. The Series resistor is the subject of this paper.

Thompson, C.; Bowman, D.; Gribble, R.F.; Griego, J.; Hinckley, W.B.; Kasik, R.J.; Reass, W.A.; Parsons, W.M. [Los Alamos National Lab., NM (United States); Cooper, R.A. [Maxwell Lab., San Diego, CA (United States)

1995-09-01

55

Semiconducting oxide gas-sensitive resistors  

International Nuclear Information System (INIS)

The overall aim of this thesis is to describe the gas sensing behaviour of a wide range of metal oxide semiconductors which exhibit tremendous changes in their electrical resistance at high temperatures (typically > 300 deg. C) upon exposure to traces (ppm) of reactive gases present in the air. The effects of surface segregation in antimony-doped tin dioxide (Sn1-ySbyO2) on both the electrical response to water vapour and the catalytic combustion of methane in the presence of water vapour were demonstrated. Effects of microstructure, and especially particle size, on the behaviour (sensitivity and selectivity) of these compounds to carbon monoxide and methane were also demonstrated. A change in behaviour correlating with the Debye length was shown. Theoretical calculation methods were used to model surface segregation and surface defects. Antimony segregates as Sb3+ and the complex (Sn(II).Vo) is a stable surface species. A model for gas response and surface reaction involving this complex is proposed. The properties of solid solution series prepared by systematic cation substitution as a way of understanding the gas response mechanism linked to the surface chemistry has been examined in (CrNbO4)x(Sn1-ySbyO2)1-x, Tix(Sn1-ySby)1-xO2, and (MWO4)x([Sn-Ti]O2)1x [with M: Mn, Fe, Co, Ni, Cu, Zn]. Effects of stoichiometry, microstructure, combustion gradient and surface segregation on gas (water, carbon monoxide, methane, propane and ammonia) sensitivity and selectivity have been observed and discussed. (author)

1998-01-01

56

Recent development of detectors with integrated capacitors and polysilicon resistors  

Energy Technology Data Exchange (ETDEWEB)

The authors developed a silicon microstrip detector with capacitive coupling of the diode strips to the metallization and with polysilicon bias resistors to each diode. It allows the decoupling of the leakage current from the input to the charge sensitive amplifier especially in the case of LSI electronics. Results are given on the coupling capacity and the breakdown voltage as well as on the polysilicon line resistance.

Evensen, L.; Hansen, T.E.; Horisberger, R.; Hubbeling, L.; Kaukonen, H.P.; Maehlum, G.; Peisert, A.; Tuuva, T.; Weilhammer, P.; Zalewska, A.

1988-02-01

57

Spin dependent trapping in a polycrystalline silicon integrated circuit resistor  

International Nuclear Information System (INIS)

Spin dependent trapping of majority carriers at trivalent silicon centers in the grain boundaries of a polycrystalline silicon integrated circuit resistor has been observed. The phenomenon has been studied both in a silicon bicrystal and in thin-film polycrystalline silicon with essentially identical results. This not only identifies the trapping center responsible for the large barriers observed at silicon grain boundaries, but also demonstrates that the technique has the sensitivity required to work with actual microelectronic devices

1983-09-01

58

Electron heating in metallic resistors at sub-Kelvin temperature  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the presence of Joule heating, the electronic temperature in a metallic resistor placed at sub-Kelvin temperatures can significantly exceed the phonon temperature. Electron cooling proceeds mainly through two processes: electronic diffusion to and from the connecting wires and electron-phonon coupling. The goal of this paper is to present a general solution of the problem, in a form that can easily be used in practical situations. As an application, we compute two quantities that depend on...

Huard, B.; Pothier, H.; Esteve, D.; Nagaev, K. E.

2007-01-01

59

Electron heating in metallic resistors at sub-Kelvin temperature  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the presence of Joule heating, the electronic temperature in a metallic resistor placed at sub-Kelvin temperatures can significantly exceed the phonon temperature. Electron cooling proceeds mainly through two processes: electronic diffusion to and from the connecting wires and electron-phonon coupling. The goal of this paper is to present a general solution of the problem, in a form that can easily be used in practical situations. As an application, we compute two quantit...

Huard, B.; Pothier, H.; Esteve, D.; Nagaev, K. E.

2007-01-01

60

System and method of modulating electrical signals using photoconductive wide bandgap semiconductors as variable resistors  

Science.gov (United States)

A system and method for producing modulated electrical signals. The system uses a variable resistor having a photoconductive wide bandgap semiconductor material construction whose conduction response to changes in amplitude of incident radiation is substantially linear throughout a non-saturation region to enable operation in non-avalanche mode. The system also includes a modulated radiation source, such as a modulated laser, for producing amplitude-modulated radiation with which to direct upon the variable resistor and modulate its conduction response. A voltage source and an output port, are both operably connected to the variable resistor so that an electrical signal may be produced at the output port by way of the variable resistor, either generated by activation of the variable resistor or propagating through the variable resistor. In this manner, the electrical signal is modulated by the variable resistor so as to have a waveform substantially similar to the amplitude-modulated radiation.

Harris, John Richardson; Caporaso, George J; Sampayan, Stephen E

2013-10-22

 
 
 
 
61

Investigation of OSL signal of resistors from mobile phones for accidental dosimetry  

CERN Document Server

Resistors from mobile phones, usually located near the human body, are considered as individual dosimeters of ionizing radiation in emergency situations. The resistors contain Al2O3, which is optically stimulated luminescence (OSL) material sensitive to ionizing radiation. This work is focused on determination of dose homogeneity within a mobile phones which was carried out by OSL measurements of resistors placed in different parts inside the mobile phone. Separate, commercially available resistors, similar in the shape and size to the resistors from circuit board of the studied mobile phone, were situated in different locations inside it. The irradiations were performed in uniform 60Co and 137Cs radiation fields, with the mobile phones connected and not connected to the cellular network. The dose decrease of 9% was measured for original resistors situated between layer of copper-clad laminate and battery, in comparison to the dose at the front of the phone. The resistors showed the lower signal when the mobi...

Mrozik, Anna; Bilski, Pawel; Gieszczyk, Wojciech

2014-01-01

62

Divided Differences of Implicit Functions  

CERN Document Server

Under general conditions, the equation $g(x,y) = 0$ implicitly defines $y$ locally as a function of $x$. In this article, we express divided differences of $y$ in terms of bivariate divided differences of $g$, generalizing a recent result on divided differences of inverse functions.

Muntingh, Georg; 10.1090/S0025-5718-2011-02486-5

2012-01-01

63

Electrical Switching of Perovskite Thin-Film Resistors  

Science.gov (United States)

Electronic devices that exploit electrical switching of physical properties of thin films of perovskite materials (especially colossal magnetoresistive materials) have been invented. Unlike some related prior devices, these devices function at room temperature and do not depend on externally applied magnetic fields. Devices of this type can be designed to function as sensors (exhibiting varying electrical resistance in response to varying temperature, magnetic field, electric field, and/or mechanical pressure) and as elements of electronic memories. The underlying principle is that the application of one or more short electrical pulse(s) can induce a reversible, irreversible, or partly reversible change in the electrical, thermal, mechanical, and magnetic properties of a thin perovskite film. The energy in the pulse must be large enough to induce the desired change but not so large as to destroy the film. Depending on the requirements of a specific application, the pulse(s) can have any of a large variety of waveforms (e.g., square, triangular, or sine) and be of positive, negative, or alternating polarity. In some applications, it could be necessary to use multiple pulses to induce successive incremental physical changes. In one class of applications, electrical pulses of suitable shapes, sizes, and polarities are applied to vary the detection sensitivities of sensors. Another class of applications arises in electronic circuits in which certain resistance values are required to be variable: Incorporating the affected resistors into devices of the present type makes it possible to control their resistances electrically over wide ranges, and the lifetimes of electrically variable resistors exceed those of conventional mechanically variable resistors. Another and potentially the most important class of applications is that of resistance-based nonvolatile-memory devices, such as a resistance random access memory (RRAM) described in the immediately following article, Electrically Variable Resistive Memory Devices (MFS-32511-1).

Liu, Shangqing; Wu, Juan; Ignatiev, Alex

2010-01-01

64

Precision high voltage divider for the KATRIN experiment  

CERN Multimedia

The Karlsruhe Tritium Neutrino Experiment (KATRIN) aims to determine the absolute mass of the electron antineutrino from a precise measurement of the tritium beta-spectrum near its endpoint at 18.6 keV with a sensitivity of 0.2 eV. KATRIN uses an electrostatic retardation spectrometer of MAC-E filter type for which it is crucial to monitor high voltages of up to 35 kV with a precision and long-term stability at the ppm level. Since devices capable of this precision are not commercially available, a new high voltage divider for direct voltages of up to 35 kV has been designed, following the new concept of the standard divider for direct voltages of up to 100 kV developed at the Physikalisch-Technische Bundesanstalt (PTB). The electrical and mechanical design of the divider, the screening procedure for the selection of the precision resistors, and the results of the investigation and calibration at PTB are reported here. During the latter, uncertainties at the low ppm level have been deduced for the new divider...

Thümmler, Th; Weinheimer, Ch

2009-01-01

65

Theory of resistor networks: the two-point resistance  

International Nuclear Information System (INIS)

The resistance between two arbitrary nodes in a resistor network is obtained in terms of the eigenvalues and eigenfunctions of the Laplacian matrix associated with the network. Explicit formulae for two-point resistances are deduced for regular lattices in one, two and three dimensions under various boundary conditions including that of a Moebius strip and a Klein bottle. The emphasis is on lattices of finite sizes. We also deduce summation and product identities which can be used to analyse large-size expansions in two and higher dimensions

2004-07-02

66

Monitoring the 1 {Omega} standard resistor by quantum Hall effect  

Energy Technology Data Exchange (ETDEWEB)

Resistance standards at ETL are maintained by quantum Hall effect. Resistance of the 1 {Omega} resistor named 69J101 is monitored. The result is R{sub 69J101} = 1 - (6.682 {+-} 0.018) x 10{sup -6} + (0.110 {+-} 0.003) x 10{sup -6} t {Omega} where t is time in years from January 1, 1994. The difference of 1 {Omega} standard between ETL and BIPM on 1990 international comparison is reduced from -0.128 ppm to -0.044 ppm.

Kinoshita, Joji; Nakanishi, Masakazu; Yoshihiro, Kazuo [Electrotechnical Lab., Ibaraki (Japan)] [and others

1994-12-31

67

Universality and superuniversality of multifractals in nonlinear resistor networks  

International Nuclear Information System (INIS)

The multifractal function f(?) is generalized to describe noisy nonlinear random resistor networks. An approximant function for the family of noise exponents is introduced that provides a good description of real percolative systems for strong nonlinearities. By mapping from this family to the multifractal function, one can approximate the latter. A scale transformation of ? in the approximation makes the multifractal function universal for all nonlinearities and by applying an additional transformation, this function becomes superuniversal, i.e., independent of the dimension. The universality is demonstrated for the Mandelbrot-Given structure and the implications of these results are discussed on real percolative systems

1989-01-01

68

Damping of power swings by control of braking resistors  

Energy Technology Data Exchange (ETDEWEB)

In this paper an analysis of the stability enhancement and improved damping of power swings in a multi-machine power system by means of thyristor-controlled braking resistor installed in the network has been presented. The control law has been derived using direct Lyapunov method and non-linear multi-machine system model. It is optimal in the sense that it causes the quickest dissipation of the power system energy released by a disturbance. Simple implementation of this control using only locally available signal has been also demonstrated. A computer simulation of a multi-machine power system model has verified the effectiveness of the proposed algorithm. (author)

Machowski, J.; Smolarczyk, A. [Warsaw University of Technology (Poland). Instytut Elektroenergetyki; Bialek, J.W. [University of Durham (United Kingdom). School of Engineering

2001-10-01

69

Properties of Ruthenia-Based Resistors Embedded in Low-Temperature Co-Firable Ceramic Substrates  

Science.gov (United States)

Commercial thick-film resistor pastes were printed on and embedded in cordierite+borosilicate glass low-temperature co-firable ceramic (LTCC) substrates. The electrical properties of the resistors were found to depend on the final microstructure. Anorthite crystals were produced by the interaction between the substrates and glass composition of the resistor films at boundaries. The anorthite crystals grown into the substrate and the resistor layer increased the overall resistance. Sedimentation of the conductive particles and glass migrating to the substrates decreased the resistor thickness during sintering. Conductive particles in the resistor films flocculated after firing at 850° and 900°C. Formation of anorthite crystals, conductive particle sedimentation, glass migration, and inter-diffusion were determined to be three major factors determining film resistivity.

Hsi, Chi-Shiung; Lee, Ming-Wei

2002-08-01

70

Simple LabVIEW DC Circuit Simulation With Series Resistors: Overview  

Science.gov (United States)

This is a downloadable simple DC circuit simulation with 2 resistors in series for studying Ohm's Law. Users can adjust the voltage and the resistors while the current changes in real time, just like the real thing. Users are then asked whether the current increases or decreases as the ohms of the resistors increases. Includes instructions on how to measure DC / AC current. This free program requires Windows 9x, NT, or above. Note that this will NOT run on Mac OS.

2009-07-17

71

Simple LabVIEW DC Circuit Simulation With Parallel Resistors: Overview  

Science.gov (United States)

This is a downloadable simple DC circuit simulation with 2 resistors in parallel with a third resistor. This is useful for studying Ohm's Law. Users can adjust the voltage and the resistors while the current changes in real time, just like the real thing. Users are then asked whether the current increases or decreases as the ohms of the resistors increases. Includes instructions on how to measure DC / AC current. This free program requires Windows 9x, NT, XP or later. Note that this will NOT run on Mac OS.

2009-08-21

72

Implanted Silicon Resistor Layers for Efficient Terahertz Absorption  

Science.gov (United States)

Broadband absorption structures are an essential component of large format bolometer arrays for imaging GHz and THz radiation. We have measured electrical and optical properties of implanted silicon resistor layers designed to be suitable for these absorbers. Implanted resistors offer a low-film-stress, buried absorber that is robust to longterm aging, temperature, and subsequent metals processing. Such an absorber layer is readily integrated with superconducting integrated circuits and standard micromachining as demonstrated by the SCUBA II array built by ROE/NIST (1). We present a complete characterization of these layers, demonstrating frequency regimes in which different recipes will be suitable for absorbers. Single layer thin film coatings have been demonstrated as effective absorbers at certain wavelengths including semimetal (2,3), thin metal (4), and patterned metal films (5,6). Astronomical instrument examples include the SHARC II instrument is imaging the submillimeter band using passivated Bi semimetal films and the HAWC instrument for SOFIA, which employs ultrathin metal films to span 1-3 THz. Patterned metal films on spiderweb bolometers have also been proposed for broadband detection. In each case, the absorber structure matches the impedance of free space for optimal absorption in the detector configuration (typically 157 Ohms per square for high absorption with a single or 377 Ohms per square in a resonant cavity or quarter wave backshort). Resonant structures with -20% bandwidth coupled to bolometers are also under development; stacks of such structures may take advantage of instruments imaging over a wide band. Each technique may enable effective absorbers in imagers. However, thin films tend to age, degrade or change during further processing, can be difficult to reproduce, and often exhibit an intrinsic granularity that creates complicated frequency dependence at THz frequencies. Thick metal films are more robust but the requirement for patterning can limit their absorption at THz frequencies and their heat capacity can be high. patterned absorber structures that offer low heat capacity, absence of aging, and uniform, predictable behavior at THz frequencies. We have correlated DC electrical and THz optical measurements of a series of implanted layers and studied their frequency dependence of optical absorption from .3 to 10 THz at cryogenic temperatures. We have modeled the optical response to determine the suitability of the implanted silicon resistor as a function of resistance in the range 10 Ohms/sq to 300 Ohms/sq.

Chervenak, J. A.; Abrahams, J.; Allen, C. A.; Benford, D. J.; Henry, R.; Stevenson, T.; Wollack, E.; Moseley, S. H.

2005-01-01

73

A high T{sub c} superconducting loss-free resistor  

Energy Technology Data Exchange (ETDEWEB)

Full text: A loss-less resistor (LLR) is introduced as a novel concept with consideration of using a high T{sub c} superconducting (HTS) inductor. This LLR resistor mainly consists of an electronic switch bridge and a inductor L. By controlling the electronic switch bridge, an equivalent resistance R(i) can be generated, and its value is R(i) = (L/i)di/dt, which allows the LLR resistor have a resistive voltage-current characteristic i.e. V(t) = i(t)R, but without thermal loss across this LLR resistor if a superconducting inductor is selected. With a HTS winding and therefore a HTS inductor, this LLR resistor is practically close to loss-free. The LLR resistor can be widely used to replace the conventional resistor in order to save energy and to improve performance of the systems. The HTS wires are identified for this application, by considering their critical currents, ac loss and possibility to make a large HTS inductor winding. To make LLR resistors for practical applications is considered with the existing HTS wires

Jin, J. X.; Chen, J. Y.; Dou, S. X. [University of Wollongong, Wollongong, NSW (Australia). Center for Superconducting and Electronic Materials

1996-12-31

74

Set, Reset, and Retention Times for Ionic and Filamentary Mem-Resistors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A dynamic systems model has previously been proposed for mem-resistors based on a driven damped harmonic oscillator differential equation describing electron and ionic depletion widths in a thin semiconductor film. This paper derives equations for set, reset, and retention times based on the previously proposed model. Keywords- mem-resistor, RRAM, ReRAM

Mouttet, Blaise

2011-01-01

75

"Weak Quantum Chaos" and its resistor network modeling  

CERN Multimedia

Weakly chaotic or weakly interacting systems have a wide regime where the common random matrix theory modeling does not apply. As an example we consider cold atoms in a nearly integrable optical billiard with displaceable wall ("piston"). The motion is completely chaotic but with small Lyapunov exponent. The Hamiltonian matrix does not look like one taken from a Gaussian ensemble, but rather it is very sparse and textured. This can be characterized by parameters $s$ and $g$ that reflect the percentage of large elements, and their connectivity, respectively. For $g$ we use a resistor network calculation that has a direct relation to the semi-linear response characteristics of the system, hence leading to a novel prediction regarding the rate of heating of cold atoms in optical billiards with vibrating walls.

Stotland, Alexander; Cohen, Doron

2011-01-01

76

Carbon Resistor Pressure Gauge Calibration at Low Stresses  

International Nuclear Information System (INIS)

The 470 Ohm carbon resistor gauge has been used in the stress range up to approximately 4-5 GPa for highly heterogeneous materials and/or divergent flow experiments. The attractiveness of the gauge is due to its rugged nature, simple construction, low cost, reproducibility, and survivability in dynamic events. The associated drawbacks are a long time response to pressure equilibration and gauge resistance hysteresis. In the range below 0.4 GPa, the gauge calibration has been mainly extrapolated into this regime. Because of the need for calibration data within this low stress regime, calibration experiments were performed using a split-Hopkinson bar, drop tower apparatus, and a gas pressure chamber. Since the performance of the gauge at elevated temperatures is a concern, the change in resistance due to heating at atmospheric pressure was also investigated. Details of the various calibration arrangements and the results will be discussed and compared a calibration curve fit to previously published calibration data

2001-06-24

77

Carbon Resistor Pressure Gauge Calibration at Low Stresses  

Science.gov (United States)

The 470 Ohm carbon resistor gauge has been used in the stress range up to 4-5 GPa for highly heterogeneous materials and/or divergent flow experiments. The attractiveness of the gauge is its rugged nature, simple construction, low cost, reproducibility, and survivability in dynamic events. Gauge drawbacks are the long time response to pressure equilibration and gauge resistance hysteresis. In the regime below 0.4 GPa, gauge calibration has been extrapolated. Because of the need for calibration data within this low stress regime, calibration experiments were performed using a split-Hopkinson bar, drop tower apparatus, and gas pressure chamber. Since the performance of the gauge at elevated temperatures is a concern, the change in resistance due to heating at atmospheric pressure was also investigated. Details of the various calibration arrangements and the results are discussed and compared to a calibration curve fit to previously published calibration data.

Cunningham, Bruce; Vandersall, Kevin S.; Niles, Angela M.; Greenwood, Daniel W.; Garcia, Frank; Forbes, Jerry W.; Wilson, William H.

2002-07-01

78

Carbon Resistor Pressure Gauge Calibration at Low Stresses  

Energy Technology Data Exchange (ETDEWEB)

The 470 Ohm carbon resistor gauge has been used in the stress range up to approximately 4-5 GPa for highly heterogeneous materials and/or divergent flow experiments. The attractiveness of the gauge is due to its rugged nature, simple construction, low cost, reproducibility, and survivability in dynamic events. The associated drawbacks are a long time response to pressure equilibration and gauge resistance hysteresis. In the range below 0.4 GPa, the gauge calibration has been mainly extrapolated into this regime. Because of the need for calibration data within this low stress regime, calibration experiments were performed using a split-Hopkinson bar, drop tower apparatus, and a gas pressure chamber. Since the performance of the gauge at elevated temperatures is a concern, the change in resistance due to heating at atmospheric pressure was also investigated. Details of the various calibration arrangements and the results will be discussed and compared a calibration curve fit to previously published calibration data.

Cunningham, B; Vandersall, K S; Niles, A M; Greenwood, D W; Garcia, F; Forbes, J W

2001-06-22

79

Carbon resistor pressure gauge calibration at low stresses  

International Nuclear Information System (INIS)

The 470 Ohm carbon resistor gauge has been used in the stress range up to 4-5 GPa for highly heterogeneous materials and/or divergent flow experiments. The attractiveness of the gauge is its rugged nature, simple construction, low cost, reproducibility, and survivability in dynamic events. Gauge drawbacks are the long time response to pressure equilibration and gauge resistance hysteresis. In the regime below 0.4 GPa, gauge calibration has been extrapolated. Because of the need for calibration data within this low stress regime, calibration experiments were performed using a split-Hopkinson bar, drop tower apparatus, and gas pressure chamber. Since the performance of the gauge at elevated temperatures is a concern, the change in resistance due to heating at atmospheric pressure was also investigated. Details of the various calibration arrangements and the results are discussed and compared to a calibration curve fit to previously published calibration data

2002-07-08

80

Investigation of shunt resistor's connection for a DC Resistive SFCL  

International Nuclear Information System (INIS)

A DC-operating resistive-type superconducting fault current limiter for AC applications (in short a DC Resistive SFCL) is based on the synergistic use of the 'resistive' and the 'rectifier' fault current limiter concepts, and allows the superconductor to operate in nearly DC current conditions. This regime of operation drastically reduces AC losses thus opening new perspectives with regard to materials, architecture of the cable, lay out of windings and cryogenics. In this paper the concept of DC resistive SFCL is resumed and a case study about its possible application in the distribution electrical system is reported. Two possible connections of external shunt resistor in order to reduce the Joule heating during the limiting phase are analysed.

2010-06-01

 
 
 
 
81

Ionization monitor with improved ultra-high megohm resistor  

Energy Technology Data Exchange (ETDEWEB)

An ionization monitor is described including: a counter chamber including electrically conductive wall means for containing an ionizable gas and an electrically conductive counting electrode extending through and electrically insulated from the wall means; whereby radiation-induced ionization of gas in the chamber causes electron flow between the counting electrode and the wall means proportional to the amount of radiation; an electrometer circuit having a high-impedance input directly connected to the counting electrode means, a low-impedance output, and 100% negative feedback means connected between the output and the input, the feedback means consisting of a high-impedance resistor having one end directly connected to the electrometer input and an other end connected to the output.

Burgess, E.T.

1988-07-05

82

A novel charge sensitive preamplifier without the feedback resistor  

International Nuclear Information System (INIS)

A novel charge sensitive preamplifier which has no resistor in parallel with the feedback capacitor is presented. No external device or circuit is required to discharge the feedback capacitor. The detector leakage and signal current flows away through the gate of the input JFET which works with its gate to source junction slightly forward biased. The DC stabilization of the preamplifier is accomplished by an additional feedback loop, which permits to equalize the current flowing through the forward biased gate to source junction and the current coming from the detector. An equivalent noise charge of less than 20 electrons rms has been measured at room temperature by using an input JFET with a transconductance to gate capacitance ratio of 4 mS/5.4 pF. (orig.)

1993-03-01

83

A novel charge sensitive preamplifier without the feedback resistor  

International Nuclear Information System (INIS)

A novel charge sensitive preamplifier which has no resistor in parallel with the feedback capacitor is presented. No external device or circuit is required to discharge the feedback capacitor. The detector leakage and signal current flows away through the gate of the first JFET which works with its gate to source junction slightly forward biased. The DC stabilization of the preamplifier is accomplished by an additional feedback loop, which permits to equalize the current flowing through the forward baised gate to source junction and the current coming from the detector. An equivalent noise charge of less than 20 electrons r.m.s. has been measured at room temperature by using an input JFET with a transconductance to gate capacitance ratio of 4 mS/5.4 pF

1992-02-24

84

Voltage controlled resistor using quasi-floating-gate MOSFETs  

Directory of Open Access Journals (Sweden)

Full Text Available A voltage controlled resistor (VCR using quasi-floating-gate MOSFETs (QFGMOS suitable for low voltage applications is presented. The performance of the VCR implemented with QFGMOS is compared with its floating-gate MOSFET (FGMOS version. It was found that QFGMOS offers better performance than FGMOS in terms of frequency response, offsets and chip area. The VCR using QFGMOS offers high bandwidth and low power dissipation and yields high value of resistance as compared to its FGMOS counterpart. The workability of the presented circuits was tested by PSpice simulations using level 3 parameters of 0.5?m CMOS technology with supply voltage of ± 0.75V. The simulations results were found to be in accordance with the theoretical predictions.

Susheel Sharma

2013-01-01

85

Stationary Regime of Random Resistor Networks Under Biased Percolation  

CERN Multimedia

The state of a 2-D random resistor network, resulting from the simultaneous evolutions of two competing biased percolations, is studied in a wide range of bias values. Monte Carlo simulations show that when the external current $I$ is below the threshold value for electrical breakdown, the network reaches a steady state with a nonlinear current-voltage characteristic. The properties of this nonlinear regime are investigated as a function of different model parameters. A scaling relation is found between $/_0$ and $I/I_0$, where $$ is the average resistance, $_0$ the linear regime resistance and $I_0$ the threshold value for the onset of nonlinearity. The scaling exponent is found to be independent of the model parameters. A similar scaling behavior is also found for the relative variance of resistance fluctuations. These results compare well with resistance measurements in composite materials performed in the Joule regime up to breakdown.

Pennetta, C; Alfinito, E; Trefan, G

2002-01-01

86

Sociology: The growing climate divide  

Science.gov (United States)

Climate change has reached the level of a 'scientific consensus', but is not yet a 'social consensus'. New analysis highlights that a growing divide between liberals and conservatives in the American public is a major obstacle to achieving this end.

Hoffman, Andrew J.

2011-07-01

87

The Divided Self in Adolescence.  

Science.gov (United States)

Interviews with adolescents revealed that they have a complex "divided metaphysics" of subjectivity, based on a dualistic view of reality versus appearance. Certain conceptual methodological issues surrounding research into self identity are discussed. (Author/DB)

Broughton, J. M.

1981-01-01

88

Indium Tin Oxide Resistor-Based Nitric Oxide Microsensors  

Science.gov (United States)

A sensitive resistor-based NO microsensor, with a wide detection range and a low detection limit, has been developed. Semiconductor microfabrication techniques were used to create a sensor that has a simple, robust structure with a sensing area of 1.10 0.99 mm. A Pt interdigitated structure was used for the electrodes to maximize the sensor signal output. N-type semiconductor indium tin oxide (ITO) thin film was sputter-deposited as a sensing material on the electrode surface, and between the electrode fingers. Alumina substrate (250 m in thickness) was sequentially used for sensor fabrication. The resulting sensor was tested by applying a voltage across the two electrodes and measuring the resulting current. The sensor was tested at different concentrations of NO-containing gas at a range of temperatures. Preliminary results showed that the sensor had a relatively high sensitivity to NO at 450 C and 1 V. NO concentrations from ppm to ppb ranges were detected with the low limit of near 159 ppb. Lower NO concentrations are being tested. Two sensing mechanisms were involved in the NO gas detection at ppm level: adsorption and oxidation reactions, whereas at ppb level of NO, only one sensing mechanism of adsorption was involved. The NO microsensor has the advantages of high sensitivity, small size, simple batch fabrication, high sensor yield, low cost, and low power consumption due to its microsize. The resistor-based thin-film sensor is meant for detection of low concentrations of NO gas, mainly in the ppb or lower range, and is being developed concurrently with other sensor technology for multispecies detection. This development demonstrates that ITO is a sensitive sensing material for NO detection. It also provides crucial information for future selection of nanostructured and nanosized NO sensing materials, which are expected to be more sensitive and to consume less power.

Xu, Jennifer C.; Hunter, Gary W.; Gonzalez, Jose M., III; Liu, Chung-Chiun

2012-01-01

89

Aristotle on Dividing the Soul  

Directory of Open Access Journals (Sweden)

Full Text Available Aristotle’s account of the soul requires an adequate division of the soul. However, Aristotle refuses to divide the soul spatially, and insists that it is divided only conceptually, that is ‘in being’ or ‘in account’. In this paper I explain what this division amounts to and how Aristotle executes it. Then I discuss three important advantages of such a division of the soul. First, it enables Aristotle to avoid problems that he identified in Plato’s account of the soul. Second, it allows him to treat a particular capacity of the soul as itself divided into distinct parts or aspects. Third, it allows him to treat a particular capacity of the soul as a distinct part or aspect of some more comprehensive capacity.

Pavel Gregoric

2008-11-01

90

Phase Separation in a Thick Film Resistor on a Calcium Borosilicate-Based Substrate  

Science.gov (United States)

A commercially available resistor paste was embedded into a calcium borosilicate glass ceramic substrate. The fabricated packages were sintered in the 700-900 °C temperature range. The interactions between the embedded resistor and the substrate were studied. Two consecutive phase separations were observed. First, at 800 °C, the diffusion of Ca2+ ions from the substrate into the embedded resistors occurred, resulting in the formation of two separated glass phases with high and low SiO2 content. When the reaction temperature increased to 850-900 °C, the separated glass phase composition reached consistent values and the second phase separation stage occurred.

Hsi, Chi?Shiung; Chen, Hua?Pin

2006-06-01

91

Phase composition and electrophysical properties of ruthenium resistors modified by oxide compounds of niobium (V)  

International Nuclear Information System (INIS)

The authors study some electrophysical properties, as well as the phase composition, of real ruthenium thick-film resistors based on lead ruthenate(IV) with additions of niobium(V) compounds by the x-ray powder diffraction method. The study revealed that regardless of the composition of the niobium-containing additions in the modified ruthenium resistor, lead ruthenate(IV), ruthenium dioxide, and Pb1.5Nb_2O /SUB 6.5/ are present in the form of crystalline phases. The electrophysical properties of resistors modified by oxide compounds of niobium are completely explicable

1986-09-01

92

Breakdown of two-phase random resistor networks  

International Nuclear Information System (INIS)

We describe the failure of two-component square- and cubic-lattice random resistor networks. The model behavior is dependent on the ratio of the conductances of the two components g, the ratio of the (brittle) failure thresholds of the two components i, the volume fraction p, and the sample size L. For much of the parameter space, the average strength of the networks shows a rather weak size effect, and a scaling argument suggests that this size effect is logarithmic. As usual, near the percolation points, there can be algebraic scaling provided i and g are very large or small. Near the limits p=0 and p=1, there is a logarithmic (''dilute-limit'') singularity in average strength. The ability to absorb damage is very strongly dependent on the model parameters. When one phase is more conducting and weaker than the other, and the strong phase is connected, the damage is usually extensive. Basically most of the weak bonds fail prior to the failure of the whole network. In the other regions of parameter space, damage is not extensive, but it does sometimes scale in a nontrivial way with the sample size

1995-02-01

93

Resistor development for N.E.C. accelerators  

International Nuclear Information System (INIS)

This paper reports on a resistor development program started because of problems that have shown themselves over a period of years with corona points. The main problem found after using corona points for fifteen years is the long term problem associated with corrosive SF6 breakdown products. The program identified that SF6 breakdown, in concentrations of 0.1 ppm caused by corona points, were sufficient to kill the nylon in a chain in several hundred hours. The problem is held in check, but not eliminated. The corrosive products generated by the corona points are not confined to the gas phase where they start, but cause corrosion of all metal and plastic surfaces on which they land. So inside the machine there is a continuous generation of particulates. These particulates are fundamentally incompatible with the operation of the high voltage accelerator. The other thing discovered about corona points is that it is very difficult to control them in such a way that the voltages across successive points in the assembly are all equal

1988-10-24

94

Design and development of a resistive voltage divider for 3MeV DC accelerator  

International Nuclear Information System (INIS)

A resistive voltage divider has been designed and developed for the measurement of 3MV DC voltage of 3MeV, 30kW industrial accelerator to be commissioned at EBC Kharghar. A resistive divider does not require calibration, provided the leakage currents through the insulating medium are kept negligible, as compared to the HV arm current. The divider ratio is 3x107 and total resistance is 46G?. The divider is made in modular form with 4 modules, each of 750 kV and 810mm length and will be located inside the HV multiplier in the SF6 environment at 6 kg/cm2 pressure. Special corona shields surround the HV resistors for corona prevention so as to maintain the divider ratio. The equipotentials are matched to the HV multiplier to avoid capacitive loading of the divider. Divider modules have been assembled and tested in simulated conditions in open air. The salient features of design, fabrication details and present status of the divider will be presented in this paper. (author)

2005-09-28

95

Teaching general concepts about sensors and transfer functions with a voltage divider  

Directory of Open Access Journals (Sweden)

Full Text Available This work proposes the use of a simple voltage divider circuit composed by one potentiometer and one resistor to simulate the behavior of the electrical output signal of linear and nonlinear sensors. It is a low cost way to implement practical experiments in classroom and it also enables the analysis of interesting topics of electricity. This work induces naturally to a class guide where students can build and characterize a voltage divider to explore several concepts about sensors output signal. As the result of this teaching activity it is expected that students understand fundamentals of voltage divider, potentiometer operation, fundamental sensor characteristics, transfer function, and, besides, associate directly concepts of physics and mathematics with a practical approach.

João E. M. Perea Martins

2011-12-01

96

Design and Implementation of Coupled-Line Wilkinson Power Dividers Using Alumina Substrate  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents design and implementation of coupled-line Wilkinson power dividers at frequency 2.4GHz using alumina substrate. This design using Wilkinson power dividers method where consist of two ??? impedance in the form of coupled lines on microstrip and one resistor is connected on the both of output ports. Design parameters used in the design of coupled lines dividers are input and output matching, insertion loss and isolation between the both output ports. The design parameters presented in graph on the simulation result from ADS2011.10 software simulation and the measurement result from vector network analyzer (VNA R3770 from Advantest. The simulation and measurement results show almost the same results where the return loss is less than -15dB, insertion loss is about -3dB and isolation between the output ports is more than -12dB.

Taufiqqurrachman

2014-03-01

97

Comparison between analytical models and finite-difference simulations in transmission-line tap resistors and L-type cross-Kelvin resistors  

Science.gov (United States)

Approximate analytical models of the transmission-line tap resistor and the cross-Kelvin resistor are compared with computer-simulated pseudo-three-dimensional resistor network models. The analytical formulas are in good agreement with the simulations over a useful range of parameters and are readily applied to the extraction of the contact resistivity and the sheet resistances of the semiconducting layer under and outside the contacts. The extraction procedure, which is easily implemented on a personal computer, is carried out for the case of alloyed AuGeNi/GaAs contacts, illustrating the importance of (1) distinguishing between layer sheet resistance under and outside the contacts and (2) considering two-dimensional current flow in the semiconducting layer.

Scorzoni, Andrea; Lieneweg, Udo

1990-01-01

98

Information Societies and Digital Divides  

CERN Multimedia

The book argues ICT are part of the set of goods and services that determine quality of life, social inequality and the chances for economic development. Therefore understanding the digital divide demands a broader discussion of the place of ICT within each society and in the international system. The author argues against the perspectives that either isolates ICT from other basic social goods (in particular education and employment) as well as those that argue that new technologies are luxury of a consumer society. Though the author accepts that new technologies are not a panacea for the problems of inequality, access to them become a condition of full integration of social life. Using examples mainly from Latin America, the work presents some general policy proposals on the fight against the digital divide which take in consideration other dimensions of social inequality and access to public goods. Bernardo Sorj was born in Montevideo, Uruguay. He is a naturalized Brazilian, living in Brazil since 1976. He ...

Sorj, Bernardo

2008-01-01

99

A new method of removing the high value feedback resistor in the charge sensitive preamplifier  

International Nuclear Information System (INIS)

A new method of removing the high value feedback resistor in the charge sensitive preamplifier is introduced. The circuit analysis of this novel design is described and the measured performances of a practical circuit are provided

1993-07-01

100

Conductivity modulation effects in diffused resistors at very high dose rate levels  

International Nuclear Information System (INIS)

Integrated circuits are susceptible to burnout at extremely high dose rate levels. Several IC technologies utilize diffused resistors which are subject to conductivity modulation. These resistors, in some cases, may not provide sufficient current limiting at high dose rate levels to preclude burnout. One solution to this problem is to utilize thin film or thick film resistors, e.g., Nichrome, to provide current limiting. Another solution is one to use diffused resistors in dielectrically isolated tubs. To facilitate this solution, engineering expressions which accurately define conductivity modulation must be developed, and the current limiting which results must be adequately estimated. The problem was previously addressed and this study extends the treatment by considering band-to-band recombination which is the most important basic effect limiting conductivity modulation at high dose rate levels

1979-12-01

 
 
 
 
101

Development of Low-Noise High Value Chromium Silicide Resistors for Cryogenic Detector Applications  

Science.gov (United States)

Extremely high sensitivity detectors, such as silicon bolometers are required in many NASA missions for detection of photons from the x-ray to the far infrared regions. Typically, these detectors are cooled to well below the liquid helium (LHe) temperature (4.2 K) to achieve the maximum detection performance. As photoconductors, they are generally operated with a load resistor and a pre-set bias voltage, which is then coupled to the input gate of a source-follower Field Effect Transistor (FET) circuit. It is imperative that the detector system signal to noise performance be limited by the noise of the detector and not by the noise of the external components. The load resistor value is selected to optimize the detector performance. These two criteria tend to be contradictory in that these detectors require load resistors in the hundreds of megaohms, which leads to a higher Johnson noise. Additionally, the physical size of the resistor must be small for device integration as required by such missions as the NASA High Resolution Airborne Wide-Band Camera (HAWC) instrument and the Submillimeter High Angular Resolution Camera (SHARC) for the Caltech Submillimeter Observatory (CSO). We have designed, fabricated and characterized thin film resistors using a CrSi/TiW/Al metal system on optical quality quartz substrates. The resistor values range from 100 megaohms to over 650 megaohms and are Johnson noise limited at LHe temperatures. The resistor film is sputtered with a sheet resistance ranging from 300 ohms to 1600 ohms and the processing sequence developed for these devices allows for chemically fine tuning the sheet resistance in-situ. The wafer fabrication process was of sufficiently high yield (>80%) providing clusters of good resistors for integrated multiple detector channels, a very important feature in the assembly of these two instruments.

Jhabvala, Murzy; Babu, Sachi; Monroy, Carlos; Darren, C.; Krebs, Carolyn A. (Technical Monitor)

2001-01-01

102

Chopper controlled resistors in VSC-HVDC transmission for WPP with full-scale converters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Large and distant offshore wind power plants can be efficiently connected to the onshore power grid network using VSC-HVDC (Voltage Source Converter based HVDC) transmission. Chopper controlled resistors can be used to limit the DC line over-voltage when there is a fault on the onshore AC grid and power transfer to the grid is obstructed. Considering the development of full scale converter based wind turbine generators (WTG), use of unit rated chopper controlled resistors...

Chaudhary, S. K.; Teodorescu, Remus; Rodri?guez Corte?s, Pedro; Kjaer, P. C.

2009-01-01

103

Au/Ti resistors used for Nb/Pb-alloy Josephson junctions. II. Thermal stability  

Energy Technology Data Exchange (ETDEWEB)

In the preceding paper bilayered Au/Ti resistors were found to have excellent electrical stability during storage at room temperature after preannealing at an elevated temperature, which is essential to design logic and memory circuits of Nb/Pb-alloy Josephson junction devices. The resistors could contact directly with the Pb-alloy control lines in which Pb and In atoms which are known to intermix easily with Au atoms are contained. Since Pb and In atoms in the control lines are separated from Au atoms of the resistors by thin Ti layers, thermal stability at the contacts is a major concern for use of the Au/Ti resistor material in the Josephson devices. In the present study, surface morphology change and diffusion mechanism at the resistor/control-line contacts were studied using x-ray diffraction and scanning electron microscopy for square-shaped Au/Ti resistors covered by Pb-In layers. The samples were isothermally annealed at temperatures ranging from 353 to 423 K. The diffusion did not occur immediately after annealing at these temperatures. After the incubation period, the interdiffusion was observed to initiate at the edges of the resistors facing to the center of the cathode. Significant amounts of the In atoms in the Pb-In layers were observed to diffuse into the Au layers of the resistors, forming AuIn/sub 2/ compounds under the Ti layers. By measuring growth rates of the AuIn/sub 2/ layers, the diffusion coefficients and the activation energy for the layer growth were determined. Also, by analyzing changes in the In concentration in the Pb-In layers during annealing, interdiffusion coefficients of In atoms in the Pb-In layers were determined using a computer simulation technique. The activation energy was about 1.1 eV.

Murakami, M.; Kim, K.K.

1984-10-01

104

Nonlinear random resistor diode networks and fractal dimensions of directed percolation clusters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We study nonlinear random resistor diode networks at the transition from the non percolating to the directed percolating phase. The resistor-like bonds and the diode-like bonds under forward bias voltage obey a generalized Ohm's law, $V \\sim I^r$. Based on general grounds as symmetries and relevance we develop a field theoretic model. We focus on the average two-port resistance, which is governed at the transition by the resistance exponent $\\phi_r$. By employing renormaliza...

Stenull, Olaf; Janssen, Hans-karl

2001-01-01

105

The electromagnetic "memory" of a dc-conducting resistor: a relativity argument and the electrical circuits  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A circuit-field problem is considered. A resistor conducting a constant current is argued to be associated with electromagnetic energy accumulated in the surrounded space, though contrary to the case of an inductor or a capacitor, this energy is always associated with both magnetic and electrical fields. The circuit-theory point of view saying that a resistor has no electromagnetic memory is accepted, but the necessarily involved (in view of the field argument) capacitance a...

Gluskin, Emanuel

2010-01-01

106

Ground-Water Modeling of Pumping Effects near Regional Ground-Water Divides and River/Aquifer Systems in the Great Lakes Basin: Results and Implications of Numerical Experiments.  

Science.gov (United States)

This report presents the results and implications of scenario numerical modeling of ground-water flow near the boundaries of the Great Lakes Basin. Two primary regional aquifer systems were modeled to determine the effects of ground-water withdrawals on t...

R. A. Sheets D. H. Dumouchelle D. T. Feinstein

2005-01-01

107

Layered ultra-thin coherent structures used as electrical resistors having low-temperature coefficient of resistivity  

Science.gov (United States)

A thin film resistor having a controlled temperature coefficient of resistance (TCR) ranging from negative to positive degrees kelvin and having relatively high resistivity. The resistor is a multilayer superlattice crystal containing a plurality of alternating, ultra-thin layers of two different metals. TCR is varied by controlling the thickness of the individual layers. The resistor can be readily prepared by methods compatible with thin film circuitry manufacturing techniques.

Werner, T.R.; Falco, C.M.; Schuller, I.K.

1982-08-31

108

Electrochemical, morphological and microstructural characterization of carbon film resistor electrodes for application in electrochemical sensors  

International Nuclear Information System (INIS)

The electrochemical and microstructural properties of carbon film electrodes made from carbon film electrical resistors of 1.5, 15, 140 ? and 2.0 k? nominal resistance have been investigated before and after electrochemical pre-treatment at +0.9 V vs SCE, in order to assess the potential use of these carbon film electrodes as electrochemical sensors and as substrates for sensors and biosensors. The results obtained are compared with those at electrodes made from previously investigated 2 ? carbon film resistors. Cyclic voltammetry was performed in acetate buffer and phosphate buffer saline electrolytes and the kinetic parameters of the model redox system Fe(CN)63-/4- obtained. The 1.5 ? resistor electrodes show the best properties for sensor development with wide potential windows, similar electrochemical behaviour to those of 2 ? and close-to-reversible kinetic parameters after electrochemical pre-treatment. The 15 and 140 ? resistor electrodes show wide potential windows although with slower kinetics, whereas the 2.0 k? resistor electrodes show poor cyclic voltammetric profiles even after pre-treatment. Electrochemical impedance spectroscopy related these findings to the interfacial properties of the electrodes. Microstructural and morphological studies were carried out using contact mode Atomic Force Microscopy (AFM), Confocal Raman spectroscopy and X-ray diffraction. AFM showed more homogeneity of the films with lower nominal resistances, related to better electrochemical characteristics. X-ray diffraction and Confocal Raman spectroscopy indicate the existence of a graphitic structure in the carbon films

2008-08-15

109

A wideband metamaterial absorber based on a magnetic resonator loaded with lumped resistors  

International Nuclear Information System (INIS)

A wideband metamaterial absorber (MA) based on a magnetic resonator loaded with lumped resistors is presented. It is composed of a one-dimensional periodic array of double U-shaped structured magnetic resonators loaded with lumped resistors, a dielectric substrate, and a metal plate. We simulated, fabricated, measured, and analyzed the MA. The experimental results show that the reflectance (S11) is below ?10 dB at normal incidence in the frequency range of 7.7 GHz–18 GHz, and the peak value is about ?20 dB. Simulated power loss density distributions indicate that wideband absorption of the MA is mainly attributable to the lumped resistors in the magnetic resonator. Further investigations indicate that the distance between two unit cells along the magnetic field direction significantly influences the performance of the MA. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

2012-12-01

110

Electrical and stability properties of molybdenum oxide based thick film resistors  

International Nuclear Information System (INIS)

Parameters of improved, recently developed thick film resistors based on molybdenum oxide pastes were investigated. Resistors of aspect ratio 1:2 were printed on various substrates. AgPd, AgPt and Ag pastes were used for contacts preparation. Spread of fired resistance, TCR, long term stability, influence of contact material, influence of kind of substrate, under and overglaze were tested. Results were very prospective. Spread of as fired resistance is lower than 10% in any case. TCR is dependent on sheet resistivity and is lower then 200 ppm/K for all compositions. (author)

2003-09-16

111

Use of light-dependent-resistor circuit to remotely reset digital constancy meter.  

Science.gov (United States)

A digital constancy meter which has been used in our institution uses a plane-parallel chamber for daily morning output checks of treatment machines. After exposure, the user has to enter the treatment room to obtain the charge reading and reset the meter for the next reading. To avoid this extra step and save time, a remote reset circuit which includes a light-dependent-resistor (LDR), was built into the meter. When the room light is turned off (or dimmed) from the console, the light-dependent-resistor will trigger a circuit which will reset the meter. PMID:2394625

Perec, A; Kubo, H

1990-08-01

112

Method for the fabrication of a semiconductor resistor with implanted ions of a neutral dopant  

International Nuclear Information System (INIS)

The semiconductor resistor consists of a single-crystal Si-body with a P-conducting resistor part that is doped with B. The P-conducting part forms a PN-transition with the Si-body. Ne-ions with an energy of 100 keV and an ion dose of 2 x 10"1"3 to 2 x 10"1"5 ions/cm"2 are implanted in the area below the PN-transition to increase the voltage linearity. The film resistance amounts at least to 30 kOhm/square. (RW)

1979-01-01

113

Method of preparing high-temperature-stable thin-film resistors  

Energy Technology Data Exchange (ETDEWEB)

A chemical vapor deposition method for manufacturing tungsten-silicide thin-film resistors of predetermined bulk resistivity and temperature coefficient of resistance (TCR) is disclosed. Gaseous compounds of tungsten and silicon are decomposed on a hot substrate to deposit a thin-film of tungsten-silicide. The TCR of the film is determined by the crystallinity of the grain structure, which is controlled by the temperature of deposition and the tungsten to silicon ratio. The bulk resistivity is determined by the tungsten to silicon ratio. Manipulation of the fabrication parameters allows for sensitive control of the properties of the resistor.

Raymond, L.S.

1980-11-12

114

Method of preparing high-temperature-stable thin-film resistors  

Energy Technology Data Exchange (ETDEWEB)

A chemical vapor deposition method for manufacturing tungsten-silicide thin-film resistors of predetermined bulk resistivity and temperature coefficient of resistance (TCR). Gaseous compounds of tungsten and silicon are decomposed on a hot substrate to deposit a thin-film of tungsten-silicide. The TCR of the film is determined by the crystallinity of the grain structure, which is controlled by the temperature of deposition and the tungsten to silicon ratio. The bulk resistivity is determined by the tungsten to silicon ratio. Manipulation of the fabrication parameters allows for sensitive control of the properties of the resistor.

Raymond, Leonard S. (Tucson, AZ)

1983-01-01

115

Determination of Reduced Number and Suitable Locations of Fuzzy Logic Controlled Braking Resistors for Transient Stability Enhancement  

Science.gov (United States)

Braking resistor is known to be a very powerful tool for transient stability improvement in electric power systems. Usually, in a large power system braking resistors are placed at each generator terminal bus which requires a high installation as well as operation cost. Also, heavy computation is required for the controllers used for the switching of the resistors. From these viewpoints, this paper directs to the study of installation of reduced number of fuzzy logic controlled braking resistors at suitable locations for transient stability enhancement. Groups of coherent generators in the power system are determined. Then one braking resistor is installed in each of the coherent group and at each of the remaining generator terminal bus. Thus, the number of braking resistors is reduced and hence the installation and operation cost as well as computational burden for the controllers are minimized. The suitable location for the braking resistor in each coherent group of generators is determined according to the values of the transient stability index as calculated for a 3LG (Three-phase-to-ground) fault at the points near the generators of the coherent group without considering the braking resistors in the system. The effectiveness of the proposed method is demonstrated through EMTP simulations for the IEEJ West-10 machine model system.

Ali, Mohd. Hasan; Murata, Toshiaki; Tamura, Junji

116

The characterisation of lead-free thick-film resistors on different low temperature Co-fired ceramics substrates  

Energy Technology Data Exchange (ETDEWEB)

Graphical abstract: Display Omitted Highlights: ? Lead free thick film resistors based on ruthenium oxide were developed. ? The compatibility of resistors with different LTCC substrates was evaluated. ? The interactions between resistors and glassy LTCC substrates were not detected. ? Electrical characteristics were comparable with commercial thick film resistors. -- Abstract: Lead-free thick-film resistors were synthesised and investigated. The thick-film resistor materials with nominal sheet resistivities from 50 ohm/sq. to 50 kohm/sq. were prepared using combinations of two lead-free glasses with reflow temperatures at 940 °C and 1240 °C, respectively, and two RuO{sub 2} powders (fine-grained and coarse-grained RuO{sub 2}). The thick-film resistors were printed and fired on alumina and on low temperature co-fired ceramics substrates and fired at 850 °C and 950 °C. The fired resistors were investigated by X-ray powder diffraction, by scanning electron microscopy and by energy dispersive X-ray analysis. The sheet resistivities, temperature coefficients of resistivity, gauge factors and noise indices were measured.

Hrovat, Marko, E-mail: marko.hrovat@ijs.si [Jožef Stefan Institute, Jamova Cesta 39, SI-1000 Ljubljana (Slovenia); CoE NAMASTE, Jamova Cesta 39, SI-1000 Ljubljana (Slovenia); Kielbasinski, Konrad [Institute of Electronic Materials Technology, Wólczy?ska 133, 01-919 Warsaw (Poland); Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw (Poland); Makarovi?, Kostja [Jožef Stefan Institute, Jamova Cesta 39, SI-1000 Ljubljana (Slovenia); CoE NAMASTE, Jamova Cesta 39, SI-1000 Ljubljana (Slovenia); Belavi?, Darko [HIPOT-RR d.o.o., Šentpeter 18, SI-8222 Oto?ec (Slovenia); CoE NAMASTE, Jamova Cesta 39, SI-1000 Ljubljana (Slovenia); Jakubowska, Malgorzata [Institute of Electronic Materials Technology, Wólczy?ska 133, 01-919 Warsaw (Poland); Faculty of Mechatronics, Warsaw University of Technology, ?w. Andrzeja Boboli 8, 02-525 Warsaw (Poland)

2012-12-15

117

A new optimized design concept of the switching network resistors of the large ITER-FEAT tokamak  

Energy Technology Data Exchange (ETDEWEB)

In the large ITER-FEAT tokamak, resistors are essential electrical components to protect the super-conducting coils but also to produce the needed high voltages in some poloidal field coils during the breakdown and plasma initiation phase to start-up the plasma current. In this specific case, the resistors, called Switching Network Resistors (SNR), must dissipate a large amount of energy but should be also able to provide accurate step resistances within wide ranges of currents and voltages. The step resistances needed in the coil circuits can be precisely determined only during experimentation with the machine. Therefore, a large flexibility has to be foreseen in the design of these resistors. As several SNRs are installed in the large tokamak ITER-FEAT, this paper describes, step by step, a new optimized resistor design concept, with regard to flexibility in operation and cost optimization.

Bareyt, B. E-mail: bareytb@itergps.naka.jaeri.go.jp; Bulgakov, S

2002-05-01

118

Advanced ceramic composite for high energy resistors. Characterization of electrical and physical properties  

International Nuclear Information System (INIS)

Full text : There is a need to characterize and apply advanced materials to improve the performance of components used in pulse power systems. One area for innovation is the use of bulk electrically conductive ceramics for non-inductive, high energy and high power electrical resistors. Standard Ceramics, Inc. has developed a unique silicon carbide structural ceramic composite which exhibits electrical conductivity. The new conductive bulk ceramic material has a controlled microstructure, which results an improved homogeneity, making the material suitable for use as a non-inductive, high energy resistor. The new material has higher density, highee peak of temperature limit and greater physical strength compared with bulk ceramics currently used for pulsed power resistors. This paper describes characterization of the material's physical and electrical properties and relates them to improvements in low-power density, as compared to existing components would be expected and derived from specific properties such as good thermal conductivity, high strength, thermal shock resistance and high temperature capability. The bulk resistor approach that weas proposed offers high reliability through better mechanical properties and simplicity of construction

2005-06-01

119

Construction of the JFT-2M Tokamak(3) --- development of semiconductor shunt resistor ---  

International Nuclear Information System (INIS)

A new type of toroidal shunt (by-pass) resistors have been successfully developed for the JFT-2M vacuum vessel. Since the vacuum vessel is electrically insulated at two toroidal positions with organic insulators, in-vacuum shunt resistors are required in order to prevent arc discharge at the insulated vessel joint and to protect the in-vessel magnetic probes and the poloidal field (PF) coils in case of plasma disruptions or misfire. Approximately 10 m? toroidal resistance is necessary based on the PF coils and power supply design conditions. For the resistors, metals can not be used because of their higher electric conductivity and small heat capability, and finally newly developed SiC ceramic has been chosen due to its moderate electric conductivity, high thermal conductivity and sufficient mechanical strength. Fifty-two cylindrical SiC pieces are built in the fastening bolts for each of the insulated vessel joints. The SiC ceramic used here has Zennercharacteristics, i.e., its conductivity rapidly decreases with the increment of applied voltage, thus it presents preferable performances in terms of providing a high toroidal resistance at plasma start-up and a lower one at disruptive plasma behavior. The plasma operation of about 4900 discharges performed so far has shown the effectiveness and applicability of this type of shunt resistors. This work has been done under the contract from JAERI and provided with a number of useful advices and suggestions by JAERI members

1983-01-01

120

Cosmic Ray Measurements by Scintillators with Metal Resistor Semiconductor Avalanche Photo Diodes  

Science.gov (United States)

An educational set-up for cosmic ray physics experiments is described. The detector is based on scintillator tiles with a readout through metal resistor semiconductor (MRS) avalanche photo diode (APD) arrays. Typical measurements of the cosmic angular distribution at sea level and a study of the East-West asymmetry obtained by such a device are…

Blanco, Francesco; La Rocca, Paola; Riggi, Francesco; Akindinov, Alexandre; Mal'kevich, Dmitry

2008-01-01

 
 
 
 
121

Hand-Drawn Resistors and a Simple Tester Using a Light-Emitting Diode  

Science.gov (United States)

A thick line drawn on a sheet of paper with a 6B pencil is electrically conductive and its resistance can be roughly estimated using a simple tester made of a light-emitting diode (LED) and a lithium coin-type cell. Using this hand-drawn resistor and the LED tester, we developed teaching materials that help students to understand how electrical…

Kamata, Masahiro; Abe, Mayumi

2012-01-01

122

Measurements of fuse and resistor characteristics for multi-megajoule capacitor bank application  

International Nuclear Information System (INIS)

Experimental tests have been conducted on commercially available fuses and resistors under fast high voltage pulsed (10 ?sec) conditions to determine their ability to protect capacitor bank components during faults. NRL's Modified Betatron Accelerator uses two multi-megajoule capacitor banks to power the toroidal and betatron magnetic field coils. The expensive high energy density capacitors in these banks must be protected from excessive peak current, voltage reversal, or charging beyond their electrical ratings in the occurrence of a fault. Adequate protection can be obtained with fuses and resistors in series with each parallel connected capacitor. The fuses must open reliably and hold off high voltage D.C. (10 - 20 kV), and the resistors must conduct high current and di/dt without failing from energy deposition or magnetic forces. The performance of the commercial fuses is well documented at low AC frequencies and currents (60 Hz/100 A) but data was not previously available for the fast high current pulsed conditions that prevail under actual fault conditions. A 20 kV 200 kJ, low inductance capacitor bank and ignitron switch were used to conduct the experiments. Peak currents in the fuses were approximately 170 kA at t - 6.5 ?s. The final fuse hold-off voltage exceeded 8 kV. Currents in the resistors ranged from - 20 - 40 kA per resistor. The experimental results have been compared to the manufacturers data from minimum melt and maximum let-through and to exploding bridge wire computer models

1986-01-01

123

Next generation KATRIN high precision voltage divider for voltages up to 65kV  

CERN Document Server

The KATRIN (KArlsruhe TRItium Neutrino) experiment aims to determine the mass of the electron antineutrino with a sensitivity of 200meV by precisely measuring the electron spectrum of the tritium beta decay. This will be done by the use of a retarding spectrometer of the MAC-E-Filter type. To achieve the desired sensitivity the stability of the retarding potential of -18.6kV has to be monitored with a precision of 3ppm over at least two months. Since this is not feasible with commercial devices, two ppm-class high voltage dividers were developed, following the concept of the standard divider for DC voltages of up to 100kV of the Physikalisch-Technische Bundesanstalt (PTB). In order to reach such high accuracies different effects have to be considered. The two most important ones are the temperature dependence of resistance and leakage currents, caused by insulators or corona discharges. For the second divider improvements were made concerning the high-precision resistors and the thermal design of the divider....

Bauer, S; Hochschulz, F; Ortjohann, H -W; Rosendahl, S; Thümmler, T; Schmidt, M; Weinheimer, C

2013-01-01

124

A high voltage storing voltage divider  

Energy Technology Data Exchange (ETDEWEB)

The divider (D) consists of a chain (G) of capacitors submerged into an insulating liquid, for instance, transformer oil, which is in a dielectric, ribbed body. Elastic rings, which have exterior projections, which rest in the walls of the body, and interior projections which support the capacitors, are used to lock the capacitors in the body of the divider. The chain by its upper end is attached through a rod and pin to the top and an electrode is turned into the lower end. The electrode is installed in tongs which are attached to a catcher, connected to the base of the divider. With the passage of a large current, large heat liberations arise which cause a change in the linear dimensions of the divider. The presence of the tongs connection of the electrode of the divider and clearances in the elastic rings eliminates mechanical damage to the divider, which increases its reliability.

Yelizarov, V.S.; Karavaytsev, Ye.F.; Kolesnikov, V.P.

1982-01-01

125

Development of high power RF divider  

International Nuclear Information System (INIS)

High power multi antenna RF heating system has been developed. The RF power of 500 KW (f = 7 - 28 MHz) is divided into twelve lines by means of 3 db coupler and two six channel power dividers, and those are fed to the twelve ICRF antennas through impedance matching circuits. (author)

1988-01-01

126

Parochial Geographies: Growing up in Divided Belfast  

Science.gov (United States)

This article explores the ways in which teenagers occupy and manage space in one divided community in Northern Ireland. Drawing on stories, maps and focus group discussions with 80 teenagers, from an interface area in Belfast, the article reveals their perceptions and experiences of divided cities, as risky landscapes. Teenagers respond to these…

Leonard, Madeleine

2010-01-01

127

Effective conductivity of particulate polymer composite electrolytes using random resistor network method  

Energy Technology Data Exchange (ETDEWEB)

The effective DC conductivity of particulate composite electrolytes was obtained by solving electrostatics equations using random resistors network method in three dimensions. The composite structure was considered to consist of three phases: matrix, particulate filler, and conductive shell that surrounded each particle; each phase possessing a different conductivity. Different particle size distributions were generated using Monte Carlo simulations. Unlike effective medium formulations, it was shown that the random resistors network method was able to predict percolation thresholds for the effective composite conductivity. It was found that the mean particle radius has a higher influence on the effective composite conductivity compared to the effect of type of the particle size distributions that were considered. The effect of the shell thickness on the composite conductivity has been investigated. It was found that the conductivity enhancement due to the presence of the conductive shell phase becomes less evident as the shell thickness increases.

Kalnaus, Sergiy [ORNL; Sabau, Adrian S [ORNL; Newman, Sarah M [ORNL; Tenhaeff, Wyatt E [ORNL; Daniel, Claus [ORNL; Dudney, Nancy J [ORNL

2011-01-01

128

Non-Gaussian Fluctuations in Biased Resistor Networks: Size Effects versus Universal Behavior  

CERN Document Server

We study the distribution of the resistance fluctuations of biased resistor networks in nonequilibrium steady states. The stationary conditions arise from the competition between two stochastic and biased processes of breaking and recovery of the elementary resistors. The fluctuations of the network resistance are calculated by Monte Carlo simulations which are performed for different values of the applied current, for networks of different size and shape and by considering different levels of intrinsic disorder. The distribution of the resistance fluctuations generally exhibits relevant deviations from Gaussianity, in particular when the current approaches the threshold of electrical breakdown. For two-dimensional systems we have shown that this non-Gaussianity is in general related to finite size effects, thus it vanishes in the thermodynamic limit, with the remarkable exception of highly disordered networks. For these systems, close to the critical point of the conductor-insulator transition, non-Gaussiani...

Pennetta, C; Reggiani, L; Ruffo, S

2005-01-01

129

Nanoporous carbon tunable resistor/transistor and methods of production thereof  

Energy Technology Data Exchange (ETDEWEB)

In one embodiment, a tunable resistor/transistor includes a porous material that is electrically coupled between a source electrode and a drain electrode, wherein the porous material acts as an active channel, an electrolyte solution saturating the active channel, the electrolyte solution being adapted for altering an electrical resistance of the active channel based on an applied electrochemical potential, wherein the active channel comprises nanoporous carbon arranged in a three-dimensional structure. In another embodiment, a method for forming the tunable resistor/transistor includes forming a source electrode, forming a drain electrode, and forming a monolithic nanoporous carbon material that acts as an active channel and selectively couples the source electrode to the drain electrode electrically. In any embodiment, the electrolyte solution saturating the nanoporous carbon active channel is adapted for altering an electrical resistance of the nanoporous carbon active channel based on an applied electrochemical potential.

Biener, Juergen; Baumann, Theodore F; Dasgupta, Subho; Hahn, Horst

2014-04-22

130

Carbon Resistor Pressure Gauge Calibration at Stresses up to 1 GPa  

Science.gov (United States)

Calibration of the 470-Ohm carbon resistor gauge is desired in the low stress region up to 1 GPa. A split-Hopkinson pressure bar, drop tower apparatus, gas pressure chamber, and gas gun have been used to perform the calibration experiments. The gauge behavior at elevated temperature was also investigated by heating the resistors to 200 C at atmospheric pressure while observing the resistance change. The motivation for this calibration work arises from the desire to increase the number of data points in the low stress regime to better establish the accuracy and precision of the gauge. Details of the various calibration arrangements and the results are discussed and compared to calibration curves fit to previously published calibration data. It was found that in most cases, the data from this work fit the calibration curves rather well.

Vandersall, Kevin S.; Niles, Angela M.; Greenwood, Daniel W.; Cunningham, Bruce; Garcia, Frank; Forbes, Jerry W.

2002-04-01

131

An evaluation of color features for a resistor color classification under various illumination situations  

Science.gov (United States)

In a previous study, we examined color spaces to read resistor lines of 11 different colors (black, brown, red, orange, yellow, green, blue, purple, gray, white, and gold). However, the color classification experiment was carried out only under a certain illumination. In order effectively to classify real resistor color lines, the color classification under various illumination conditions must be considered. In this paper, we examine 10 color features (RGB, XYZ, YCbCr, YIQ, HSI, HSV, HLS, L*u*v*, L*a*b*, and I1I2I3) under the various illumination. The experimental results show the effectiveness of the L*u*v* color feature. Furthermore, in a very small training sample size situation, the classification performance of the u*v* feature vector except for an intensity element L* outperforms that of L*u*v*.

Mitani, Yoshihiro; Hamamoto, Yoshihiko

2014-01-01

132

A silicon microstrip detector with integrated coupling capacitors and polysilicon biasing resistors  

International Nuclear Information System (INIS)

In this paper we report on the development of a silicon microstrip detector with integrated coupling capacitors and polysilicon biasing resistors. These new detectors show the same performance as standard detectors made at our laboratory with regard to leakage current and spatial resolution. Leakage currents as low as 200 pA/strip at 120 volts and a spatial resolution as good as 3.5 ?m has been achieved. (author)

1987-01-01

133

Development of resistor-type dummy load for high-voltage test operation  

International Nuclear Information System (INIS)

We developed the resistor-type dummy load as a substitute for the klystron used in the factory test of the modulator. The dummy load can be used with 350 kV applied voltage, and 460 W input power in insulation oil. Compared to the klystron, the output waveforms are nearly same. Therefore, the dummy load has been used for the evaluation of the electrical characteristic of the modulator. The resistance value depends on the applied voltage, and varies secularly. (author)

2010-08-04

134

A comprehensive study of resistor-loaded planar dipole antennas for ground penetrating radar applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ground penetrating radar (GPR) systems are increasingly being used for the detection and location of buried objects within the upper regions of the earth’s surface. The antenna is the most critical component of such a system. This thesis presents a comprehensive study of resistor-loaded planar dipole antennas for GPR applications using both theory and experiments. The theoretical analysis is performed using the finite difference time domain (FDTD) technique. The analysis starts with the mos...

Uduwawala, Disala

2006-01-01

135

Random manifolds in non-linear resistor networks Applications to varistors and superconductors  

CERN Document Server

We show that current localization in polycrystalline varistors occurs on paths which are, usually, in the universality class of the directed polymer in a random medium. We also show that in ceramic superconductors, voltage localizes on a surface which maps to an Ising domain wall. The emergence of these manifolds is explained and their structure is illustrated using direct solution of non-linear resistor networks.

Donev, A; Duxbury, P M

2001-01-01

136

Dynamic Systems Model for Ionic Mem-Resistors based on Harmonic Oscillation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Memristive system models have previously been proposed to describe ionic memory resistors. However, these models neglect the mass of ions and repulsive forces between ions and are not well formulated in terms of semiconductor and ionic physics. This article proposes an alternative dynamic systems model in which the system state is derived from a second order differential equation in the form of a driven damped harmonic oscillator. Application is made to Schottky and tunnelin...

Mouttet, Blaise

2011-01-01

137

Control of a fractional chaotic system based on a fractional-order resistor—capacitor filter  

International Nuclear Information System (INIS)

We present a new fractional-order resistor—capacitor controller and a novel control method based on the fractional-order controller to control an arbitrary three-dimensional fractional chaotic system. The proposed control method is simple, robust, and theoretically rigorous, and its anti-noise performance is satisfactory. Numerical simulations are given for several fractional chaotic systems to verify the effectiveness and the universality of the proposed control method

2012-09-01

138

Low-temperature thick-film dielectrics and resistors for metal substrates  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this work, a set of low-temperature thick-film dielectrics consisting of two high-lead low-temperature glasses, stabilised by various amounts of alumina filler, is characterised on alumina and aluminium metal, as a function of firing temperature. Corresponding resistors based on the same glasses as the dielectrics, but with RuO2 as a conductive phase, were studied on the dielectrics. The purpose of these materials is to enable deposition of thick- film electronics onto substrate...

Jacq, Caroline; Maeder, Thomas; Vionnet Menot, Sonia; Ryser, Peter

2005-01-01

139

Gauge factor enhancement driven by heterogeneity in thick-film resistors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present a simple picture of the gauge factor (GF) enhancement in highly heterogeneous materials such as thick-film resistors. We show that when the conducting phase is stiffer than the insulating one, the local strains within this latter are enhanced with respect to the averaged macroscopic strain. Within a simple model of electron tunneling processes, we show that the enhanced local strain leads to values of GF higher than those expected for a homogeneous system. Moreove...

Grimaldi, C.; Ryser, P.; Straessler, S.

2000-01-01

140

Pyramidal resistor networks for electrical impedance tomography with partial boundary measurements  

International Nuclear Information System (INIS)

We introduce an inversion algorithm for electrical impedance tomography (EIT) with partial boundary measurements in two dimensions. It gives stable and fast reconstructions using sparse parameterizations of the unknown conductivity on optimal grids that are computed as part of the inversion. We follow the approach in Borcea et al (2008 Inverse Problems 24 035013) and Vasquez (2006 PhD thesis Rice University, Houston, TX, USA) that connects inverse discrete problems for resistor networks to continuum EIT problems, using optimal grids. The algorithm in Borcea et al (2008 Inverse Problems 24 035013) and Vasquez (2006 PhD Thesis Rice University, Houston, TX, USA) is based on circular resistor networks, and solves the EIT problem with full boundary measurements. It is extended in Borcea et al (2010 Inverse Problems 26 045010) to EIT with partial boundary measurements, using extremal quasi-conformal mappings that transform the problem to one with full boundary measurements. Here we introduce a different class of optimal grids, based on resistor networks with pyramidal topology, that is better suited for the partial measurements setup. We prove the unique solvability of the discrete inverse problem for these networks and develop an algorithm for finding them from the measurements of the Dirichlet to Neumann map. Then, we show how to use the networks to define the optimal grids and to approximate the unknown conductivity. We assess the performance of our approach with numerical simulations and compare the results with those in Borcea et al (2010)

2010-10-01

 
 
 
 
141

A study on embedded resistor components fabricated by laser micro-cladding and rapid prototype  

International Nuclear Information System (INIS)

With the rapid development of IC and packaging, electronic devices are required to be smaller, to have a high-density integration, to become multifunction and to be of lower cost and high-reliability. Thick-film technology is not able to meet the current developing demands because of its shortcomings, such as the limit of pattern resolution, the severe torsion and delay of high-speed signal transmission. The speed and quality of signal transmission will be improved if embedded resistor components are directly integrated in the multiplayer substrate of multi-chip or laminated module, and high-density integration and reliability are achieved because the short interconnection and the less soldering point. In this paper, a technique named laser micro-cladding and rapid prototype is used to directly fabricate embedded resistor units on the multiplayer ceramic substrate without using a mask and high-temperature sintering, and without trimming resistor, which will simplify processing and decrease cost as well as improving high-speed and reliable performance

2006-08-25

142

The dependence of electrical and magnetic properties of the frequency-dependent resistor shell of ferromagnetic granules concentration and sizes  

International Nuclear Information System (INIS)

The investigation results of electric and magnetic properties of frequency-dependent resistor sheath consist of mixture of polymeric dielectric and ferrite granules oriented in magnetic field are presented

2009-04-01

143

Divide County High School Receives National Recognition.  

Science.gov (United States)

Describes highlights of educational programs at Divide County High School (Crosby, North Dakota), which was one of the few rural schools cited by President Reagan in 1984 for excellence in education under the Secondary School Recognition Program. (BRR)

Stammen, Ronald

1985-01-01

144

Frequency divider is free of spurious outputs  

Science.gov (United States)

Frequency divider provides sixteen output states free of spurious pulses from four input circuits. The input is binary coded, and a change of one in the input only changes the number of output states by one.

Mc Dermond, D.

1966-01-01

145

Democratisation and Conflict in Ethnically Divided Societies  

Directory of Open Access Journals (Sweden)

Full Text Available This article reviews three important factors in the academic debate on ethnic civil wars: the role of ethnicity in causing and structuring violence, the spread of ethnic civil wars once they have started, and the influence of democratic transitions in divided societies. The review displays the range of discussion on conflict, the state and political systems in ethnically divided societies, covering both theoretical and empirical contributions.

Judith Vorrath

2009-03-01

146

Quality estimation of thick-film resistor terminations based on electrical parameters extraction  

Science.gov (United States)

The RoHS and WEEE regulation forced the large investigations for environmental friendly materials in electronic. The Lead and cadmium which was the significant component of resistors and conductors used in thick-film technology have to be replaced. Quick and precise measurement techniques need to be elaborated to maintain consumer's demand. Usually the test samples with the conductive and resistive layers were used for electrical parameters measurements. The layer thickness measurements and mean value of resistance allowed calculating the sheet resistance. Such a method of measurement have very serious disadvantage. The calculated mean value can be significantly affected by resistors terminations, especially if silver conductor is used, which is known as an easily migrating material. The solution was known and involved preparing and printing samples with the reference terminations. Silver platinum and silver palladium conductors are less susceptible to migration, therefore they were used in previous investigations. The reference terminations improves the precision of calculating sheet resistance, however they enlarges the number of measurements and its influence could still be significant. The authors proposed completely new method of sheet resistance calculation. Such a calculated value called True Sheet Resistance do not depend on the phenomena taking place at the termination, The second evaluated value called Offset indicates the influence of the terminations on measured resistance, and also termination quality. Its value is correlated with the diffusion rate at the interface between conductive film and resistive film at the termination. The usability of this method was proven by performing multiple firing test. One kind of resistive layer was printed on different kinds of conductive layers. The samples were fired sequently and measured. Then the old method of resistor properties evaluation was compared to the new one.

Kie?basi?ski, Konrad; Jakubowska, Ma?gorzata; Kalenik, Jerzy; M?o?niak, Anna

2008-01-01

147

Implementation of Non Restoring Interval Divider unit  

Directory of Open Access Journals (Sweden)

Full Text Available Interval arithmetic provides a general methodology for bounding errors. Interval arithmetic provides reliability and accuracy by computing a lower and upper bound in which each result is guaranteed to reside. An interval’s width ensures the maximum possible error. The approaches consisted on developing hardware support for interval arithmetic division unit by incorporating existing conventional floating point units. This unit requires slightly more area than a conventional floating point divider. It provides a significant performance improvement over software implementations of interval divider. This paper presents the implementation of non restoring interval division algorithm for double precision binary data.

Milind R. Patel, Prof. Deepali H. Shah

2012-02-01

148

On the Conduction Mechanism of Silicate Glass Doped by Oxide Compounds of Ruthenium (Thick Film Resistors  

Directory of Open Access Journals (Sweden)

Full Text Available The results of the investigation of conduction mechanism of silicate glass doped by oxide compounds of ruthenium (thick film resistor are reported. The formation of diffusion zones in the softened glass during firing process of the mixture of the glass and the dopant powders is considered. As the result the doping glass becomes conductive. These diffusion zones have higher conductivity and act as percolation levels for the free charge carriers. The effect of tem-perature and duration of firing process on the conductivity of doped glass is considered. Experimental results are in a good agreement with the model.

Gulmurza Abdurakhmanov

2011-05-01

149

On the Transformation of a Floating Resistor Oscillator to Grounded Passive Element Oscillators  

Directory of Open Access Journals (Sweden)

Full Text Available A generalization method is used to transform a floating resistor oscillator circuit to a family of sixteen grounded capacitor oscillators using the current conveyor (CCII or the inverting current conveyor (ICCII or combination of both. Two of the oscillator circuits have a floating property. A new family of sixteen oscillator circuits is generated from the known circuit using the adjoint circuit theorem. It is also shown that the oscillator under consideration leads to the generation of other known and new grounded passive element oscillators employing the differential voltage current conveyor (DVCC and the balanced output current conveyor (BOCCII.

Ahmed M Soliman

2010-09-01

150

Resistor array infrared projector nonuniformity correction: search for performance improvement III  

Science.gov (United States)

Resistor array infrared projector nonuniformity correction (NUC) is currently limited in fidelity. In the flood technique a fundamental limitation has been the inevitable presence of Moire fringes. In this paper, an advanced NUC procedure is described in which the Moire patterns are successfully subtracted, leading to improved levels of residual nonuniformity. It is shown that, irrespective of the projection technology, the Moire fringes exist at the unit-under-test image plane where they appear in general as sampling noise. Their control through choice of mapping ratio is discussed.

Joyce, Robert A.; ?wierkowski, Leszek; Williams, Owen M.

2008-05-01

151

Calculation of conductivity and polarization resistance of composite SOFC electrodes from random resistor networks  

Energy Technology Data Exchange (ETDEWEB)

A model for total conductivity and polarization resistance of composite electrodes in solid oxide fuel cells is proposed. The model is based on numerically solving Kirchoff`s current law for the resistor network resulting from scattering predetermined fractions of electrode and electrolyte particles at random on the sites of a three-dimensional cubic lattice. The model predicts an almost abrupt rise in total conductivity at an electrode-particle volume-fraction of 0.3, and a polarization resistance with a relatively broad minimum close to this percolation threshold, in good agreement with experimental results.

Sunde, S. [SINTEF Materials Technology, Trondheim (Norway)

1995-04-01

152

Circuit elements at optical frequencies: nano-inductors, nano-capacitors and nano-resistors  

CERN Document Server

We present some ideas for synthesizing nanocircuit elements in the optical domain using plasmonic and non-plasmonic nanoparticles. Three basic circuit elements, i.e., nano-inductors, nano-capacitors, and nano-resistors, are discussed in terms of small nanostructures with different material properties. Coupled nanocircuits and parallel and series combinations are also envisioned, which may provide road maps for the synthesis of more complex nanocircuits in the IR and visible bands. Ideas for the optical implementation of right-handed and left-handed nano-transmission lines are also forecasted.

Engheta, N; Alu, A; Engheta, Nader; Salandrino, Alessandro; Alu, Andrea

2004-01-01

153

Self-adjusting resistor unit in the detector-voltage supply of a charge-sensitive pre-amplifier for an ionization detector  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A self-adjusting resistor unit is described which stabilizes the bias voltage of a detector for ionising particles, while always keeping the parallel thermal noise of the bias resistor significantly below the detector shot noise. The user is exempted from adjusting the bias resistor to the detector leakage current for achieving optimum operation conditions. Moreover, the unit avoids the drop of the operation voltage on the detector when the reverse current increases up to several orders of ma...

2012-01-01

154

An Analysis of the Fuzzy Logic Controlled Braking Resistor for Transient Stability Improvement in Multi-Machine Power System  

Science.gov (United States)

This paper presents the results of analyses about transient stability augmentation by the fuzzy logic controlled braking resistor in a Multi-Machine power system. Following a major disturbance in electric power system, variable rotor speed of the generator is measured, and then the current through the braking resistor is controlled by the firing-angle of the thyristor switch which is controlled by the fuzzy logic. Thus the braking resistor controls the accelerating power in generators and makes the system transiently stable. Simulations are performed by using EMTP (Electro-Magnetic Transients Program). Through the simulation results of both balanced (3LG: Three-phase-to-ground) and unbalanced (1LG: Single-line-to ground, 2LG: Double-line-to ground and 2LS: Line-to-line) faults at different points in the IEEJ West-10 machines system model, the effectiveness of the proposed fuzzy logic controlled braking resistor is demonstrated and the optimal conductance value of the braking resistor in enhancing the transient stability is investigated.

Ali, Mohd. Hasan; Murata, Toshiaki; Tamura, Junji

155

The Role of TiO2 in Ceramic Bulk Interference Suppressing Resistor Integrated with Car Spark Plug  

Science.gov (United States)

Spark plug resistors operate under extreme conditions (200°C, 4.2 MPa, peak-to-peak working voltage Up-p of 15 to 30 kV, and instantaneous power of 26 kW). The dissipated heat has to be distributed evenly in the entire structure. The deciding factor for the homogeneity of the structure of a resistive body, which also influences the resistance value of resistors, is titanium dioxide. Its influence on the phase transition of the glass binding the components of the resistive body has been investigated by means of differential thermal analysis (DTA). Homogeneity assessment of the structure has been carried out by means of a scanning electron microscope. Titanium undergoes partial reduction during thermal processing of the resistor. The oxidation number of titanium has been determined by means of electron spectroscopy for chemical analysis x-ray photoelectron spectroscopy (ESCA-XPS). Electrical stability of the resistors has been measured using a simulator device for the car ignition system. The resistors with no TiO2 content get damaged and those with TiO2 exhibit electrical stability.

Klimiec, Ewa; Nowak, Stanis?aw; Zaraska, Wies?aw; Stoch, Jerzy

2007-07-01

156

Electric force microscopy investigation of the microstructure of thick film resistors  

Science.gov (United States)

Maps of the electric field distribution on the surface of thick film resistors (TFRs) have been acquired by using electric force microscopy (EFM). TFRs based on various types of conducting phases (Bi-ruthenate, Pb-ruthenate, or RuO2) and with different volume fractions in the glassy matrix have been examined. Scanning electron microscopy, x-ray energy dispersive spectroscopy and x-ray diffraction have been used to correlate the EFM results to the morphological, microchemical, and structural characteristics of the samples. The evolution of the TFRs microstructure and the segregation characteristic with the firing conditions have been investigated. The results showed that the concentration of the electric field around the conductive grains is a general feature of all the films, independently of the resistor composition, and a meander-like path of charge carriers on a microscopic scale has been assessed. The observations also indicated that at high firing temperatures the segregated structure did not disappear, but on the contrary was enhanced. All the results are critically discussed in relation to the electrical and piezoresistive properties of the TFRs and suggestions for new models to correlate the microstructure and the electric properties are presented.

Alessandrini, A.; Valdrè, G.; Morten, B.; Prudenziati, M.

2002-10-01

157

Pushing beyond resistors and constipators: implementation considerations for infection prevention best practices.  

Science.gov (United States)

Despite increased knowledge in the science of infection prevention, the implementation of evidence-based best practices remains a challenge. The dissemination of infection prevention risk reduction best practices should be approached with flexibility and a collaborative perspective. High-quality evidence and cost assessments to support interventions are important initial considerations. An implementation framework should be contextually appropriate, take into account an organization's culture, and be mindful of an approach that minimizes complexity. Trialing an intervention within a specific unit may later lead to increased uptake organization wide. Highly functional collaborations with effective leaders are needed for successful implementation. Leadership for infection prevention initiatives may include upper level management; however, hospital epidemiologists and infection preventionists often play this role. Although published data fail to identify a single best integrative strategy for infection prevention practice change, success has been associated with education initiatives and seminars, audit and feedback, distribution of educational materials, marketing, mass media, positive deviance, and the employment of champions, facilitators, role models, and opinion leaders. Local personnel, such as organizational resistors and constipators, can be barriers to idea dissemination and implementation. In addition to a thoughtfully conceived implementation strategy, dealing with infection prevention resistors and constipators includes getting their buy-in early in the dissemination process, working around them, or terminating their employment. More data are needed to best define which infection prevention dissemination strategies are most effective. PMID:24407546

Bearman, Gonzalo; Stevens, Michael P

2014-01-01

158

A New Control Method of a Large-Capacity Capacitor Simulator with an Inner Series Resistor  

Science.gov (United States)

This paper proposes a new control method for the previously proposed large-capacity capacitor simulator, which can perform an inner series resistor of the EDLCs. In the proposed large-capacity capacitor simulator, one of three legs performs a bi-directional dc-dc converter. The others are used for a single-phase PWM rectifier. In the charging operation of the proposed large-capacity simulator, one-leg is used as a boost converter. Most power, which is stored in the proposed simulator, is injected to the utility through the PWM rectifier. In the discharging operation, the one-leg performs a buck converter. Most power, which is supplied to the load, is from the utility through the PWM rectifier. Thus the proposed simulator performs a large-capacity capacitor with an inner resistor in both charging and discharging operations. The basic principle of the proposed simulator is discussed in detail. The validity and excellent practicability of the proposed control method for the large-capacity capacitor simulator are confirmed using PSIM software.

Tanaka, Atsushi; Hiraki, Eiji; Tanaka, Toshihiko

159

Some annealing properties of low-energy-antimony -implanted silicon resistors  

International Nuclear Information System (INIS)

Shallow-implanted antimony in silicon can be used in fabricating n-type silicon resistors with very low temperature coefficient of resistance (TCR), controllably and reproducibly. This paper reports a study of the sheet resistance of silicon resistors implanted with 121Sb at 10 keV, for various doses and annealing conditions. The methods used in fabricating samples and taking measurements were described in an earlier paper (Solid State Electronics, 20, 803, 1977). For high doses approximately 1015Sb/cm2, it was found that two-stage annealing(2) - preannealing at 5500C followed by annealing at 10000C - improves the electrical conductivity. For low doses, 1012Sb/cm2, the final annealing determines the conductivity. For medium doses, approximately 1013-1014Sb/cm2, the interplay of damage-annealing and activation of Sb in Si introduces complications, giving a crossover of sheet resistance vs implant dose for various annealing temperatures. For doses around 3 x 1013cm-2, the resistances are very insensitive to the details of annealing sequence and temperature; also the TCR is very low, about 50 ppm/0C. The effect of annealing conditions for various doses, resistivities and TCR values are discussed. (author)

1979-01-01

160

New mechanism to cross the phantom divide  

International Nuclear Information System (INIS)

Recently, type Ia supernova data appear to support a dark energy whose equation of state w crosses -1, which is a much more amazing problem than the acceleration of the universe. We show that it is possible for the equation of state to cross the phantom divide by a scalar field in gravity with an additional inverse power-law term of the Ricci scalar in the Lagrangian. The necessary and sufficient condition for a universe in which the dark energy can cross the phantom divide is obtained. Some analytical solutions with w-1 are obtained. A minimally coupled scalar with different potentials, including quadratic, cubic, quantic, exponential and logarithmic potentials are investigated via numerical methods, respectively. All these potentials lead to the crossing behavior. We show that it is a robust result which is hardly dependent on the concrete form of the potential of the scalar. (orig.)

2011-06-01

 
 
 
 
161

New mechanism to cross the phantom divide  

Energy Technology Data Exchange (ETDEWEB)

Recently, type Ia supernova data appear to support a dark energy whose equation of state w crosses -1, which is a much more amazing problem than the acceleration of the universe. We show that it is possible for the equation of state to cross the phantom divide by a scalar field in gravity with an additional inverse power-law term of the Ricci scalar in the Lagrangian. The necessary and sufficient condition for a universe in which the dark energy can cross the phantom divide is obtained. Some analytical solutions with w<-1 or w>-1 are obtained. A minimally coupled scalar with different potentials, including quadratic, cubic, quantic, exponential and logarithmic potentials are investigated via numerical methods, respectively. All these potentials lead to the crossing behavior. We show that it is a robust result which is hardly dependent on the concrete form of the potential of the scalar. (orig.)

Du, Yunshuang; Zhang, Hongsheng; Li, Xin-Zhou [Shanghai Normal University, Shanghai United Center for Astrophysics (SUCA), Shanghai (China)

2011-06-15

162

New mechanism to cross the phantom divide  

Science.gov (United States)

Recently, type Ia supernova data appear to support a dark energy whose equation of state w crosses -1, which is a much more amazing problem than the acceleration of the universe. We show that it is possible for the equation of state to cross the phantom divide by a scalar field in gravity with an additional inverse power-law term of the Ricci scalar in the Lagrangian. The necessary and sufficient condition for a universe in which the dark energy can cross the phantom divide is obtained. Some analytical solutions with w-1 are obtained. A minimally coupled scalar with different potentials, including quadratic, cubic, quantic, exponential and logarithmic potentials are investigated via numerical methods, respectively. All these potentials lead to the crossing behavior. We show that it is a robust result which is hardly dependent on the concrete form of the potential of the scalar.

Du, Yunshuang; Zhang, Hongsheng; Li, Xin-Zhou

2011-06-01

163

Low phase noise digital frequency divider  

Science.gov (United States)

A low phase noise frequency divider composed of a grating arrangement is disclosed. The grating arrangement supplies selected portions of an input reference signal to be divided to a tuned circuit without any phase noise due to the grating action. The arrangement which in one embodiment consists of an FET is connected to the tuned circuit input to short out the input except when the input reference signal amplitude crosses ground level in a positive direction and a gate enabling signal is present at the gate electrode of the FET. The gate enabling signal alone does not decouple the tuned circuit input from ground, therefore phase noise, due to the leading and trailing edges of each gate-enabling signal, is substantially eliminated.

Lutes, G. F., Jr. (inventor)

1973-01-01

164

Analyzing Broadband Divide in the Farming Sector  

DEFF Research Database (Denmark)

Agriculture industry has been evolving for centuries. Currently, the technological development of Internet oriented farming tools allows to increase the productivity and efficiency of this sector. Many of the already available tools and applications require high bandwidth in both directions, upstream and downstream connection. The main constraint is that farms are naturally located in rural areas where the required access broadband data rates are not available. This paper studies the broadband divide in relation to the Danish agricultural sector. Results show how there is an important difference between the broadband availability for farms and the rest of the households/buildings the country. This divide may be slowing down the potential technological development of the farming industry, in order to keep their competitiveness in the market. Therefore, broadband development in rural areas could be one of the points to focus in a near future broadband access plans.

Jensen, Michael; Gutierrez Lopez, Jose Manuel

2013-01-01

165

The Phantom Divide in String Gas Cosmology  

CERN Document Server

One of the main virtues of string gas cosmology is that it resolves cosmological singularities. Since the Universe can be approximated by a locally asymptotically de Sitter spacetime by the end of the inflationary era, a singularity theorem implies that these cosmologies effectively violate the Null Energy Condition [not just the Strong Energy Condition]. We stress that this is an extremely robust result, which does not depend on assuming that the spatial sections remain precisely flat in the early Universe. This means, however, that it must be possible for string cosmologies to cross the recently much-discussed "phantom divide" [from w -1, where w is the equation-of-state parameter]. This naturally raises the question as to whether the phantom divide can be crossed again, to account for recent observations suggesting that w < -1 at the present time. We argue that non-perturbative string effects rule out this possibility, even if the NEC violation in question is only "effective".

McInnes, B

2005-01-01

166

Power divider of the MP 10  

International Nuclear Information System (INIS)

The operation of the MP 10 power divider and resistances (600 megaohms, metal oxide resistances, in the column and in the tube of the MP 10), are investigated. The whole system is used in Vivitron accelerator (Strasbourg, France). The aim of the study is a better understanding of the machine's electrical operation. The resistances are tested under sulphur hexafluoride pressure and under high voltage. The results allowed the characterization of those resistances for use under operating conditions

1989-01-01

167

REGENERATIVE GAS TURBINES WITH DIVIDED EXPANSION  

DEFF Research Database (Denmark)

Recuperated gas turbines are currently drawing an increased attention due to the recent commercialization of micro gas turbines with recuperation. This system may reach a high efficiency even for the small units of less than 100 kW. In order to improve the economics of the plants, ways to improve their efficiency are always of interest. Recently, two independent studies have proposed recuperated gas turbines to be configured with the turbine expansion divided, in order to obtain higher efficiency. The idea is to operate the system with a gas generator and a power turbine, and use the gas from the gas generator part for recuperation ahead of the expansion in the power turbine. The present study is more complete than the predecessors in that the ranges of the parameters have been extended and the mathematical model is more realistic using an extensive simulation program. It is confirmed that the proposed divided expansion can be advantageous under certain circumstances. But, in order for todays micro gas turbines to be competitive, the thermodynamic efficiencies will have to be rather high. This requires that all component efficiencies including the recuperator effectiveness will have to be high. The advantages of the divided expansion manifest themselves over a rather limited range of the operating parameters, that lies outside the range required to make modern micro turbines economically competitive.

Elmegaard, Brian; Qvale, Einar Bjørn

2004-01-01

168

Positive temperature coefficient resistors as high-power pulse switches - Performance limitations, temperature effects, and triggering behavior  

Science.gov (United States)

Positive temperature coefficient resistors are evaluated in the self-heating mode as pulse generators and as opening switches in inductive storage pulse power supplies. Results from both carbon-filled polymer devices, as well as from barium-titanate-based devices, are shown. Theoretical switched powers of close to a 1/4 MW are calculated for honeycomb-shaped BaTiO3 positive temperature coefficient resistors. Switching times in the millisecond range are achieved. Pulse duration varies with ambient temperature, but this can be counteracted by using capacitative triggering. Surface flashover was one of the critical failure mechanisms. The results point toward further improved device designs.

Ford, R.; Kahn, M.

1987-03-01

169

The two-point resistance of a resistor network: a new formulation and application to the cobweb network  

Science.gov (United States)

We consider the problem of two-point resistance in a resistor network previously studied by one of us (Wu 2004 J. Phys. A: Math. Gen. 37 6653). By formulating the problem differently, we obtain a new expression for the two-point resistance between two arbitrary nodes which is simpler and can be easier to use in practice. We apply the new formulation to the cobweb resistor network to obtain the resistance between two nodes in the network. Particularly, our results prove a recently proposed conjecture on the resistance between the center node and a node on the network boundary. Our analysis also solves the spanning tree problem on the cobweb network.

Izmailian, N. Sh; Kenna, R.; Y Wu, F.

2014-01-01

170

New mechanism to cross the phantom divide  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Recently, type Ia supernovae data appear to support a dark energy whose equation of state $w$ crosses -1, which is a much more amazing problem than the acceleration of the universe. We show that it is possible for the equation of state to cross the phantom divide by a scalar field in the gravity with an additional inverse power-law term of Ricci scalar in the Lagrangian. The necessary and sufficient condition for a universe in which the dark energy can cross the phantom divi...

Du, Yunshuang; Zhang, Hongsheng; Li, Xin-zhou

2010-01-01

171

Investigation of shunt resistor's connection for a DC Resistive SFCL  

Energy Technology Data Exchange (ETDEWEB)

A DC-operating resistive-type superconducting fault current limiter for AC applications (in short a DC Resistive SFCL) is based on the synergistic use of the 'resistive' and the 'rectifier' fault current limiter concepts, and allows the superconductor to operate in nearly DC current conditions. This regime of operation drastically reduces AC losses thus opening new perspectives with regard to materials, architecture of the cable, lay out of windings and cryogenics. In this paper the concept of DC resistive SFCL is resumed and a case study about its possible application in the distribution electrical system is reported. Two possible connections of external shunt resistor in order to reduce the Joule heating during the limiting phase are analysed.

Imparato, S; Morandi, A; Fabbri, M; Negrini, F; Ribani, P L, E-mail: salvatore.imparato@mail.ing.unibo.i [Department of Electrical Engineering, University of Bologna, Viale Risorgimento 2, 40136 Bologna (Italy)

2010-06-01

172

Functional Model of Carbon Nanotube Programmable Resistors for Hybrid Nano/CMOS Circuit Design  

Science.gov (United States)

Hybrid Nano (e.g. Nanotube and Nanowire) /CMOS circuits combine both the advantages of Nano-devices and CMOS technologies; they have thus become the most promising candidates to relax the intrinsic drawbacks of CMOS circuits beyond Moore’s law. A functional simulation model for an hybrid Nano/CMOS design is presented in this paper. It is based on Optically Gated Carbon NanoTube Field Effect Transistors (OG-CNTFET), which can be used as 2-terminal programmable resistors. Their resistance can be adjusted precisely, reproducibly and in a non-volatile way, over three orders of magnitude. These interesting behaviors of OG-CNTFET promise great potential for developing the non-volatile memory and neuromorphic adaptive computing circuits. The model is developed in Verilog-A language and implemented on Cadence Virtuoso platform with Spectre 5.1.41 simulator. Many experimental parameters are included in this model to improve the simulation accuracy.

Zhao, Weisheng; Agnus, Guillaume; Derycke, Vincent; Filoramo, Ariana; Gamrat, Christian; Bourgoin, Jean-Philippe

173

Calculating two-point resistances in distance-regular resistor networks  

International Nuclear Information System (INIS)

An algorithm for the calculation of the resistance between two arbitrary nodes in an arbitrary distance-regular resistor network is provided, where the calculation is based on stratification introduced in Jafarizadeh and Salimi (2006 J. Phys. A: Math. Gen. 39 1-29) and the Stieltjes transform of the spectral distribution (Stieltjes function) associated with the network. It is shown that the resistances between a node ? and all nodes ? belonging to the same stratum with respect to the ? (R??(i), ? belonging to the ith stratum with respect to the ?) are the same. Also, the analytical formulae for two-point resistances R??(i), i=1,2,3, are given in terms of the size of the network and corresponding intersection numbers. In particular, the two-point resistances in a strongly regular network are given in terms of its parameters (v, ?, ?, ?). Moreover, the lower and upper bounds for two-point resistances in strongly regular networks are discussed

2007-05-11

174

Modernizing the automatic temperature-regulating systems for electric resistor furnaces  

International Nuclear Information System (INIS)

An analysis of the technical level of heat-treating equipment at the sector's plants showed that automation was either insufficient or completely lacking. Modern heat-treating technology makes stringent demands on heat-treating equipment, including electric resistor furnaces. Therefore, it became necessary to modernize these furnaces and equip them with modern automatic temperature control systems (ATCSs). This is most urgent for furnaces which handle nuclear-power-station parts, which must not only be held at a certain temperature for a definite time, but which also require a complex process with established heating rates in each time period. The heat-treatment data are recorded in the part's passport certificate, and the temperatures of both the heatingzone atmosphere and the heat-treated part are monitored

1985-01-01

175

Use of a Pre-Insertion Resistor to Minimize Zero-Missing Phenomenon and Switching Overvoltages  

DEFF Research Database (Denmark)

With the increasing use of High-Voltage Cables, which have different electric characteristics from Overhead Lines, phenomenon like current zero-missing start to appear more often on the transmission systems. Methods to prevent zero-missing phenomenon are still being studied and compared to see which countermeasure works the best. Technically the best way to avoid zero-missing phenomenon produces very high switching overvoltages, making the operator to choose to either avoid the zero-missing phenomenon or to minimize the switching transients. This paper presents a method of determining an optimal value of the resistance of the pre-insertion resistor that results in minimizing both the zero-missing phenomenon and switching overvoltages simultaneously.

Bak, Claus Leth; da Silva, Filipe Miguel Faria

2009-01-01

176

Conquering the digital divide: Botswana and South Korea digital divide status and interventions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Background: Botswana is putting in place initiatives towards establishing itself as a knowledgebased economy. Transformation from a resource-based to a knowledge-based economy is partly hinged on innovation, research and development capability, knowledge channels, and the funding of research and development activities.

Objectives: Bridging the digital divide and narrowing the intra-national divide brings about global informatio...

Sedimo, Nonofo C.; Bwalya, Kelvin J.; Tanya du Plessis

2011-01-01

177

Solution of Poisson's equation in a volume conductor using resistor mesh models: Application to event related potential imaging  

Science.gov (United States)

In electroencephalography (EEG) and event related potentials (ERP), localizing the electrical sources at the origin of scalp potentials (inverse problem) imposes, in a first step, the computation of scalp potential distribution from the simulation of sources (forward problem). This article proposes an alternative method for mimicing both the electrical and geometrical properties of the head, including brain, skull, and scalp tissue with resistors. Two resistor mesh models have been designed to reproduce the three-sphere reference model (analytical model). The first one (spherical resistor mesh) closely mimics the geometrical and electrical properties of the analytical model. The second one (cubic resistor mesh) is designed to conveniently handle anatomical data from magnetic resonance imaging. Both models have been validated, in reference to the analytical solution calculated on the three-sphere model, by computing the magnification factor and the relative difference measure. Results suggest that the mesh models can be used as robust and user-friendly simulation or exploration tools in EEG/ERP.

Franceries, X.; Doyon, B.; Chauveau, N.; Rigaud, B.; Celsis, P.; Morucci, J.-P.

2003-03-01

178

Measurement of small ion beams by thermal ionisation mass spectrometry using new 10(13) Ohm resistors.  

Science.gov (United States)

We tested 5 newly manufactured - prototype - 10(13)Ohm resistors in the feedback loop of Faraday cup amplifiers to measure small ion beams by Thermal Ionisation Mass Spectrometry (TIMS). The high Ohmic resistors installed in the TRITON Plus at the VU University Amsterdam theoretically have 10 times lower noise levels relative to the default 10(11)Ohm resistors. To investigate the precision and accuracy of analyses using these new amplifiers we measured Sr and Nd isotopes of reference standards at a range of ion currents (3.2×10(-16) to 1×10(-12) A, corresponding to intensities of 32 ?V to 100 mV on a default 10(11)Ohm amplifier) and on small amounts of material (100 and 10 pg). Internal precision and external reproducibility for Sr and Nd isotope ratios are both better when collected on 10(13) compared 10(12)Ohm resistors and to the default 10(11)Ohm resistors. At an (87)Sr ion current of 3×10(-14) A (3 mV on a 10(11)Ohm amplifier) the internal precision (2?SE) of (87)Sr/(86)Sr is 5 times better for 10(13)Ohm resistors compared to 10(11)Ohm resistors. The external reproducibility (2?SD) at this beam intensity is 9 times better. Multiple 100 and 10 pg Sr standards, ran to exhaustion, yielded low (87)Sr/(86)Sr compared to the long term average (e.g. 10 pg average=0.710083±164 (n=11) instead of 0.710244±12, n=73). The average off-set for 10 pg standards can be explained by a loading blank contribution of 1.3 pg. In contrast, Nd data on 100 pg and 10 pg samples are accurate suggesting that Nd loading blanks do not compromise the data. The external reproducibility of (143)Nd/(144)Nd on 100 pg samples is 125 ppm and 3.3‰ on 10 pg samples (2?RSD=relative standard deviation, n=10). Thus, variability in Nd and Sr isotope ratios in the 4th decimal place, e.g. (143)Nd/(144)Nd 0.5110-0.5119 or (87)Sr/(86)Sr 0.7100-0.7109, can be resolved in 10 to 100 pg samples provided that the procedural blanks and chemical separation are optimal. For measurements in the beam intensity range usually covered by ion counting (<3 mV or 2×10(5) cps) we obtain a (143)Nd/(144)Nd internal precision (2?SE) of 480 ppm for a (143)Nd intensity of 6.25×10(4) cps (1 mV) and 1% at an intensity of 2×10(3) cps (32 ?V on a 10(11)Ohm amplifier). We find that at intensities higher than 2×10(4) cps the precision using the 10(13)Ohm resistors is better than for ion counting owing to instability and non-linearity behaviour of the ion counting system. Our results indicate that between 2×10(4) cps and an ion current of 2×10(-13) A (20 mV on a 10(11)Ohm amplifier) it is beneficial to use the high gain amplifiers instead of (multi) ion counting or Faraday cups equipped with the standard 10(11)Ohm resistors. This finding suggests that the newly developed high gain resistors could potentially be valuable in applications that currently use (multiple) ion counting to measure small ion beams (e.g. U-series, Re-Os, Pu, Pb). In addition to improved precision, the use of Faraday cups equipped with high resistance amplifiers is more practical in terms of the required calibration procedure and in the flexibility in the collector set-up compared to using multiple ion counting arrays. PMID:24636410

Koornneef, J M; Bouman, C; Schwieters, J B; Davies, G R

2014-03-28

179

The Bread Book Multiplying and Dividing  

CERN Document Server

Bread is an important and useful food and can be bought from stores and small bakeries. Most loaves of bread are shaped like rectangular prisms. Flour, water, yeast, and salt are the key ingredients for making bread. A baker uses a recipe with different measurements of flour and water for each loaf. A baker's dozen is 13 loaves of bread, which is one more than a regular dozen.

Hyland, Tony

2008-01-01

180

Bridging the Divide between Science and Journalism  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract There are countless reasons nearly every scientist should learn how to communicate effectively with the media, including increased understanding of critical research findings to attract or sustain funding and build new professional partnerships that will further propel forward research. But where do scientists begin? Bridging the Divide between Science and Journalism offers practical tips for any scientist looking to work with the media. Given the traditional and internet-based sources for medical research and healthcare-related news now available, it is imperative that scientists know how to communicate their latest findings through the appropriate channels. The credible media channels are managed by working journalists, so learning how to package vast, technical research in a form that is appetizing and "bite-sized" in order to get their attention, is an art. Reducing years of research into a headline can be extremely difficult and certainly doesn't come naturally to every scientist, so this article provides suggestions on how to work with the media to communicate your findings.

Marincola Francesco M

2010-03-01

 
 
 
 
181

Vegetation baseline report : Connacher great divide project  

Energy Technology Data Exchange (ETDEWEB)

This baseline report supported an application by Connacher Oil and Gas Ltd. to the Alberta Energy and Utilities Board (EUB) and Alberta Environment (AENV) for the Great Divide Steam Assisted Gravity Drainage (SAGD) Project. The goal of the report was to document the distribution and occurrence of ecosite phases and wetland classes in the project footprint as well as to document the distribution of rare plants; rare plant communities: and intrusive species and old growth communities, including species of management concern. A methodology of the baseline report was presented, including details of mapping and field surveys. Six vegetation types in addition to the disturbed land unit were identified in the project footprint and associated buffer. It was noted that all vegetation types are common for the boreal forest natural regions. Several species of management concern were identified during the spring rare plant survey, including rare bryophytes and non-native or invasive species. Mitigation was identified through a slight shift of the footprint, transplant of appropriate bryophyte species and implementation of a weed management plan. It was noted that results of future surveys for rare plants will be submitted upon completion. It was concluded that the effects of the project on existing vegetation is expected to be low because of the small footprint, prior disturbance history, available mitigation measures and conservation and reclamation planning. 27 refs., 5 tabs., 4 figs.

NONE

2005-08-01

182

Analyses of power output of piezoelectric energy-harvesting devices directly connected to a load resistor using a coupled piezoelectric-circuit finite element method.  

Science.gov (United States)

This paper presents, for the first time, a coupled piezoelectric-circuit finite element model (CPC-FEM) to analyze the power output of a vibration-based piezoelectric energy-harvesting device (EHD) when it is connected to a load resistor. Special focus is given to the effect of the load resistor value on the vibrational amplitude of the piezoelectric EHD, and thus on the current, voltage, and power generated by the device, which are normally assumed to be independent of the load resistor value to reduce the complexity of modeling and simulation. The presented CPC-FEM uses a cantilever with a sandwich structure and a seismic mass attached to the tip to study the following characteristics of the EHD as a result of changing the load resistor value: 1) the electric outputs: the current through and voltage across the load resistor; 2) the power dissipated by the load resistor; 3) the displacement amplitude of the tip of the cantilever; and 4) the shift in the resonant frequency of the device. It is found that these characteristics of the EHD have a significant dependence on the load resistor value, rather than being independent of it as is assumed in most literature. The CPC-FEM is capable of predicting the generated output power of the EHD with different load resistor values while simultaneously calculating the effect of the load resistor value on the displacement amplitude of the tip of the cantilever. This makes the CPC-FEM invaluable for validating the performance of a designed EHD before it is fabricated and tested, thereby reducing the recurring costs associated with repeat fabrication and trials. In addition, the proposed CPC-FEM can also be used for producing an optimized design for maximum power output. PMID:19574142

Zhu, Meiling; Worthington, Emma; Njuguna, James

2009-07-01

183

A novel 180° hybrid power divider  

Science.gov (United States)

We describe the design, construction and performance of a novel 180° hybrid power divider for L-band (1.3-1.8 GHz). The hybrid is based on a double ridged waveguide cavity that also integrates a band pass filter. The device will operate at 77 K inside a cryogenically cooled receiver to be installed at the primary focus of the Sardinia Radio Telescope. The hybrid has three ports consisting of N-type coaxial connectors whose central pins are attached to launching probes located inside the double ridge waveguide structure. The signal is launched into the cavity from an input probe located on one cavity end and is extracted from two output probes on the opposite end. The output probes are arranged in balanced configuration, are axially symmetric, and aligned along the same axis. Both input and output probes are located in front of reactive loads consisting of shaped tunerless backshorts that provide broad band responses with low reflection coefficient. The band pass filter is located in the middle of the cavity, between the two input and output transitions. The dimensions of the device (excluding connectors) are 70 x 57.2 x 254.4 mm3. The design was optimized using a commercial electromagnetic simulator. From 1.3-1.8 GHz the measured output reflection coefficient was less than -17dB , the coupling and the phase difference between inputs and output was respectively, 3+/-0.25dB and 1800+/-0.90, over the full band. The amplitude and phase balance performances are much superior to that of commercially available devices.

Valente, G.; Navarrini, A.; Pisanu, T.

2010-07-01

184

Circular resistor networks for electrical impedance tomography with partial boundary measurements  

International Nuclear Information System (INIS)

We introduce an algorithm for the numerical solution of electrical impedance tomography (EIT) in two dimensions, with partial boundary measurements. The algorithm is an extension of the one in Borcea et al (2008 Inverse Problems 24 035013 (31pp)) and Vasquez (2006 PhD Thesis Rice University, Houston, TX, USA) for EIT with full boundary measurements. It is based on resistor networks that arise in finite volume discretizations of the elliptic partial differential equation for the potential on so-called optimal grids that are computed as part of the problem. The grids are adaptively refined near the boundary, where we measure and expect better resolution of the images. They can be used very efficiently in inversion, by defining a reconstruction mapping that is an approximate inverse of the forward map, and acts therefore as a preconditioner in any iterative scheme that solves the inverse problem via optimization. The main result in this paper is the construction of optimal grids for EIT with partial measurements by extremal quasiconformal (Teichmüller) transformations of the optimal grids for EIT with full boundary measurements. We present the algorithm for computing the reconstruction mapping on such grids, and we illustrate its performance with numerical simulations. The results show an interesting trade-off between the resolution of the reconstruction in the domain of the solution and distortions due to artificial anisotropy induced by the distribution of the measurement points on the accessible boundary

2010-04-01

185

Three-dimensional random resistor-network model for solid oxide fuel cell composite electrodes  

Energy Technology Data Exchange (ETDEWEB)

A three-dimensional reconstruction of solid oxide fuel cell (SOFC) composite electrodes was developed to evaluate the performance and further investigate the effect of microstructure on the performance of SOFC electrodes. Porosity of the electrode is controlled by adding pore former particles (spheres) to the electrode and ignoring them in analysis step. To enhance connectivity between particles and increase the length of triple-phase boundary (TPB), sintering process is mimicked by enlarging particles to certain degree after settling them inside the packing. Geometrical characteristics such as length of TBP and active contact area as well as porosity can easily be calculated using the current model. Electrochemical process is simulated using resistor-network model and complete Butler-Volmer equation is used to deal with charge transfer process on TBP. The model shows that TPBs are not uniformly distributed across the electrode and location of TPBs as well as amount of electrochemical reaction is not uniform. Effects of electrode thickness, particle size ratio, electron and ion conductor conductivities and rate of electrochemical reaction on overall electrochemical performance of electrode are investigated.

Abbaspour, Ali [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 2G6 (Canada); Luo Jingli, E-mail: jingli.luo@ualberta.c [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 2G6 (Canada); Nandakumar, K. [Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA (United States)

2010-04-30

186

Calculating two-point resistances in distance-regular resistor networks  

Energy Technology Data Exchange (ETDEWEB)

An algorithm for the calculation of the resistance between two arbitrary nodes in an arbitrary distance-regular resistor network is provided, where the calculation is based on stratification introduced in Jafarizadeh and Salimi (2006 J. Phys. A: Math. Gen. 39 1-29) and the Stieltjes transform of the spectral distribution (Stieltjes function) associated with the network. It is shown that the resistances between a node {alpha} and all nodes {beta} belonging to the same stratum with respect to the {alpha} (R{sub {alpha}}{sub {beta}{sup (i)}}), {beta} belonging to the ith stratum with respect to the {alpha}) are the same. Also, the analytical formulae for two-point resistances R{sub {alpha}}{sub {beta}{sup (i)}}, i=1,2,3, are given in terms of the size of the network and corresponding intersection numbers. In particular, the two-point resistances in a strongly regular network are given in terms of its parameters (v, {kappa}, {lambda}, {mu}). Moreover, the lower and upper bounds for two-point resistances in strongly regular networks are discussed.

Jafarizadeh, M A [Department of Theoretical Physics and Astrophysics, University of Tabriz, Tabriz 51664 (Iran, Islamic Republic of); Sufiani, R [Department of Theoretical Physics and Astrophysics, University of Tabriz, Tabriz 51664 (Iran, Islamic Republic of); Jafarizadeh, S [Department of Electrical and computer engineering, University of Tabriz, Tabriz 51664 (Iran, Islamic Republic of)

2007-05-11

187

Calculating two-point resistances in distance-regular resistor networks  

Science.gov (United States)

An algorithm for the calculation of the resistance between two arbitrary nodes in an arbitrary distance-regular resistor network is provided, where the calculation is based on stratification introduced in Jafarizadeh and Salimi (2006 J. Phys. A: Math. Gen. 39 1-29) and the Stieltjes transform of the spectral distribution (Stieltjes function) associated with the network. It is shown that the resistances between a node ? and all nodes ? belonging to the same stratum with respect to the ? (R_{\\alpha\\beta^{(i)}} , ? belonging to the ith stratum with respect to the ?) are the same. Also, the analytical formulae for two-point resistances R_{{\\alpha\\beta^{(i)}}}, i=1,2,3 , are given in terms of the size of the network and corresponding intersection numbers. In particular, the two-point resistances in a strongly regular network are given in terms of its parameters (v, ?, ?, ?). Moreover, the lower and upper bounds for two-point resistances in strongly regular networks are discussed.

Jafarizadeh, M. A.; Sufiani, R.; Jafarizadeh, S.

2007-05-01

188

Power system stabilization by a combined control using superconducting magnetic energy storage with system damping resistors  

Energy Technology Data Exchange (ETDEWEB)

Efficient power system stabilization control was examined using a control model combined with a superconducting magnetic energy storage (SMES) with system damping resistors(SDR), and the estimation method of required capacities was proposed for the SMES and SDR. A one-machine infinite-bus system was adopted as the model assuming long-distance large scale transmission, and the SMES and SDR were connected to the system end near a generator. As the results of numerical analyses, frequent small undamped power oscillations could be effectively stabilized by only the SMES, and large oscillations could be effectively stabilized by the SMES after oscillations were depressed by the suitably connected SDRs. A converter of 580MVA in capacity and energy of 200MJ were required to stabilize the power system of 2000MVA by only SMES, and on the other hand, a converter of only 230MVA and energy of only 150MJ were required as the SDR of 1000MVA was combined with the system. 6 refs., 11 figs., 2 tabs.

Mitani, Yasunori; Tsuji, Kiichiro; Murakami, Yoshishige (Osaka Univ. (Japan))

1988-08-01

189

Accurate calibration of resistance ratios between 1 M? and 1 G? using series resistors  

International Nuclear Information System (INIS)

As shown in high-resistance key comparisons carried out by the Consultative Committee for Electricity and Magnetism (CCEM), Inter-American Metrology System (SIM) and European Association of National Metrology Institutes (EURAMET), the accuracy of 10 M? and 1 G? resistances depends on ratio values between the reference resistance and unknown resistance and the accuracy of the reference resistance, which is determined with a quantized Hall resistance standard. This paper presents a method for calibrating 10:1 ratios in a high-resistance bridge using series resistors simply and accurately. By applying the 10:1 ratio errors determined using the presented method, the combined relative standard uncertainty for 1 G? resistance measurements using a modified Wheatstone bridge was estimated to be on the 1 × 10?6 level. The method was also applied to 1 G? resistance measurements using a direct-current comparator resistance bridge. It was found that the 1 G? resistances determined by the two bridges agreed within 2.4 × 10?6 ?/?. We expect that the presented method can also be used to calibrate arbitrary resistance ratios

2011-11-01

190

Prevention of Transformer Saturation at a Black Start by Resistor Insertion of 500kV CB  

Science.gov (United States)

A generating plant can not energize longer transmission lines at once after blackout. The generating plant energize shorter transmission lines firstly, then circuit breaker turns on to connect other transmission lines through the transformer. Transient over voltage oscillation may occur in the transmission lines caused by the resonance of the transmission line. It is reported that the peak voltage exceeds more than 2p.u. when the non-sinusoidal wave voltage caused by saturation in the transformer core excites the resonated transmission line. This paper describes the effect for preventing saturation of transformer by turning on contactors with appropriate resistors before main contactors of the 500kV circuit breaker. The first part presents the mechanism of preventing saturation in the transformer core by pre-resistor insertion of 500kV circuit breaker. The second part presents the expected effect in the actual power system simulated by analytical model using a transients simulation program, EMTP.

Nagashima, Hiroshi; Kosugi, Narifumi; Shimojo, Toshikazu; Furukawa, Nobuhiko; Kusunoki, Kiyoshi; Sugeta, Takayuki

191

DVCCs Based High Input Impedance Voltage-Mode First-Order Filters Employing Grounded Capacitor and Resistor  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A voltage-mode high input impedance first-order highpass, lowpass and allpass filters using two differential voltage current conveyors (DVCCs), one grounded capacitor and one grounded resistor is presented. The highpass, lowpass and allpass signals can be obtained simultaneously from the circuit configuration. The suggested filter uses a canonical number of passive components without requiring any component matching condition. The simulation results confirm the theoretical analysis.

Horng, J. W.

2010-01-01

192

Digital politics divide : the digital divide in building political e-practices  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study explores the relation between Internet and politics from a cross-national perspective of analysis. In the domain of the political sciences, the Internet has been welcomed for its potential to facilitate political practice. However, it is also commonly noted that the Internet is not equally distributed and not everybody can equally make the most of its potential. This is why the Digital Divide is perceived as the obstacle which limits the potential of the Internet to influence polit...

Calderaro, Andrea

2010-01-01

193

A Dividing Ratio Changeable Digital PLL with Low Jitter Using a Multiphase Clock Divider  

Science.gov (United States)

Since a phase locked loop (PLL) is used in the clock extraction of digital communication and high-density digital recording, it is required to have simultaneously low jitter, fast pull-in, and wide lock-in range characteristics. However, in the case of the conventional dividing ratio changeable digital PLL based on phase state memory and double clock-edge detection (PM-DCPLL), the output jitter in the steady state becomes no less than the half pulse width of the base clock controlling the loop, and the upper bound frequency of lock-in range is limited accordingly. In this paper, we propose the dividing ratio changeable digital phase locked loop (MC-DCPLL) with low jitter, wide lock-in range and fast pull-in characteristics using the multi-phase clock divider. Since the output jitter of this circuit is the 1 phase difference of the multi-phase clock in a steady state. The circuit can thus reduce the output jitter to 1/k of that of conventional PM-DCPLL when the k phase clock is used. Therefore, the upper bound frequency becomes k times as high as that of conventional PM-DCPLL. Furthermore, the initial pull-in is completed in one period of the input signal by using the initial pull-in circuit.

Fujimoto, Kuniaki; Yahara, Mitsutoshi; Sasaki, Hirofumi

194

Seasonal variation in frequency of dividing cells of freshwater phytoplankters.  

Science.gov (United States)

The frequency of dividing cells (FDC) of a natural phytoplankton community was studied seasonally in a freshwater pond to which water directly from Lake Kasumigaura was supplied. Phytoplankton samples were collected every 3 h at three depths (5, 30 and 75 cm) over 24 h periods in each of the four seasons and examined for FDC, cell size and abundance. Dominant phytoplankton species were Synedra ulna, Cyclotella kutzingiana, Chlamydomonas cingulata and Oscillatoria tenuis with Melosira italica, Cryptomonas ovata, and Synechococcus sp. being seasonally abundant. All species showed a similar FDC pattern related to the light-dark period that is a moderately phased division with the maximum FDC between 21:00-03:00. PMID:11329805

Jahan, N; Alam, M G; Sugiura, N; Norman, C P; Maekawa, T

2001-04-01

195

Electrical Properties of Al2O3- and MnO2-Doped Thick Film Resistors on AlN Substrates  

Science.gov (United States)

Owing to the interaction between lead borosilicate glass and AlN, the commercial resistor pastes which were developed for Al2O3 substrates are not applicable to AlN substrates. The conventional solution is to develop alternate glass compositions such as alkaline earth borosilicate glass to optimize compatibility with the AlN substrates. In this study, an additive-doping method was adopted to solve the problem of incompatibility between AlN substrates and resistor pastes. The Al2O3 and MnO2 powders were deliberately introduced into the as-received resistor pastes, and the interaction between AlN and glass was thus reduced or avoided. With the optimal control of sintering conditions, it is possible to produce stable thick film resistors on AlN substrates with the temperature coefficient of resistance values of less than ± 100 ppm/°C.

Chen, Lih-Shan; Fu, Shen-Li; Wu, Jun-Hong

2002-05-01

196

Avaliação de modelo de extração da água do solo por sistemas radiculares divididos entre camadas de solo com propriedades hidráulicas distintas Evaluation of a root-soil water extraction model by root systems divided over soil layers with distinct hydraulic properties  

Directory of Open Access Journals (Sweden)

Full Text Available A avaliação da capacidade de raízes de plantas em extrair água do solo é de grande importância na modelagem da taxa de transpiração e, para entender o crescimento e rendimento vegetal e o balanço de água e de solutos no solo. Para testar um modelo de extração radicular macroscópico baseado no processo em escala microscópica, descreveram-se os resultados de um experimento com plantas cujo sistema radicular foi dividido entre camadas de solo com propriedades hidráulicas contrastantes. Um experimento de lisímetro dividido com plantas de sorgo foi realizado em Piracicaba-SP. Quatro lisímetros com dois compartimentos separados fisicamente (split-pot foram construídos e preenchidos com material de dois tipos de solo de diferentes classes texturais (um solo de textura média - AR e outro de textura argilosa - AG. Durante um mês e meio foi imposto um regime hídrico, alternando a irrigação entre os compartimentos. O teor de água nos compartimentos dos lisímetros foi monitorado com TDR e tensiômetros. O material dos dois solos foi analisado conforme método-padrão quanto às suas propriedades de retenção e condução da água. A densidade radicular foi determinada por pesagem no fim do experimento, tendo ficado em torno de duas vezes maior no solo AR do que no AG. Observou-se que a extração de água ocorreu preferencialmente do compartimento do lisímetro com maior potencial de fluxo matricial. Em certas ocasiões houve transferência de água do lado de maior para o de menor potencial de fluxo matricial, com a liberação da água ao solo pelo sistema radicular (hydraulic lift. Para compensar o efeito da heterogeneidade da distribuição radicular e da atividade radicular, incluiu-se, no modelo, um fator empírico f de correção. O modelo testado descreveu bem 80 % das observações com a utilização de valores de f de 0,01506 e 0,003713, para os solos AR e AG, respectivamente. O modelo simulou a liberação de água ao solo mais frequentemente do que ela ocorreu no experimento. Esse fato pode indicar que a resistência interna do sistema radicular, não contabilizada pelo modelo, pode ter papel importante nas relações hídricas na rizosfera.Evaluating plant root capacity in extrating water from the soil is important for transpiration modeling and to understand crop growth and yield and soil water and nutrient balance. Aiming to test a macroscopic root water extraction model based on the microscopic process description, an experiment was described in which the root system of plants penetrated different soil layers with contrasting hydraulic properties. Four lysimeters containing two physically divided compartments were built and filled with material of two soils with different texture (a medium textured soil - AR and a clayey soil - AG. During a month and a half a water regime was imposed alternating the irrigation among the compartments. The soil water content in the compartments was measured with TDR and tensiometers. Soil hydraulic properties - retention and conductivity - were analyzed by standard methods. Root density was determined by weighing at the end of the experiment, resulting in values twice as high in AR than in AG soil. It was observed that water extraction occurred preferentially from the lysimeter compartments with the highest matric flux potential. Occasionally, water transfer from the compartment with higher matric flux potential to the lower one was observed, releasing water from root to soil (hydraulic lift. To compensate for the effect of heterogeneity of root distribution and root activity and soil-root contact, an empirical factor f was added to the model. Its value was determined by a numerical fitting procedure aiming at the highest correlation between model and observation in the four lysimeters. The model described 80% of the observations satisfactorily by using these f values, which were 0.01506 and 0.003713, respectively, for AR and AG. Model predictions indicated a much more frequent water release from roots to soil than observed in the experimen

Marlon Gomes da Rocha

2010-08-01

197

The Digital Divide in the Liberal State: a Canadian Perspective  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The "digital divide" has emerged as a public policy challenge. This paper examines universal access public policy development in Canada within a North American context and its implications for addressing the digital divide. It concludes that the digital divide will not be eliminated either through public policy or the market due to the liberal public philosophy that is unique to and so strong in North America. The concept of the digital divide represents the dual structure characteristic of N...

Birdsall, William F.

2000-01-01

198

Avaliação de modelo de extração da água do solo por sistemas radiculares divididos entre camadas de solo com propriedades hidráulicas distintas / Evaluation of a root-soil water extraction model by root systems divided over soil layers with distinct hydraulic properties  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A avaliação da capacidade de raízes de plantas em extrair água do solo é de grande importância na modelagem da taxa de transpiração e, para entender o crescimento e rendimento vegetal e o balanço de água e de solutos no solo. Para testar um modelo de extração radicular macroscópico baseado no proces [...] so em escala microscópica, descreveram-se os resultados de um experimento com plantas cujo sistema radicular foi dividido entre camadas de solo com propriedades hidráulicas contrastantes. Um experimento de lisímetro dividido com plantas de sorgo foi realizado em Piracicaba-SP. Quatro lisímetros com dois compartimentos separados fisicamente (split-pot) foram construídos e preenchidos com material de dois tipos de solo de diferentes classes texturais (um solo de textura média - AR e outro de textura argilosa - AG). Durante um mês e meio foi imposto um regime hídrico, alternando a irrigação entre os compartimentos. O teor de água nos compartimentos dos lisímetros foi monitorado com TDR e tensiômetros. O material dos dois solos foi analisado conforme método-padrão quanto às suas propriedades de retenção e condução da água. A densidade radicular foi determinada por pesagem no fim do experimento, tendo ficado em torno de duas vezes maior no solo AR do que no AG. Observou-se que a extração de água ocorreu preferencialmente do compartimento do lisímetro com maior potencial de fluxo matricial. Em certas ocasiões houve transferência de água do lado de maior para o de menor potencial de fluxo matricial, com a liberação da água ao solo pelo sistema radicular (hydraulic lift). Para compensar o efeito da heterogeneidade da distribuição radicular e da atividade radicular, incluiu-se, no modelo, um fator empírico f de correção. O modelo testado descreveu bem 80 % das observações com a utilização de valores de f de 0,01506 e 0,003713, para os solos AR e AG, respectivamente. O modelo simulou a liberação de água ao solo mais frequentemente do que ela ocorreu no experimento. Esse fato pode indicar que a resistência interna do sistema radicular, não contabilizada pelo modelo, pode ter papel importante nas relações hídricas na rizosfera. Abstract in english Evaluating plant root capacity in extrating water from the soil is important for transpiration modeling and to understand crop growth and yield and soil water and nutrient balance. Aiming to test a macroscopic root water extraction model based on the microscopic process description, an experiment wa [...] s described in which the root system of plants penetrated different soil layers with contrasting hydraulic properties. Four lysimeters containing two physically divided compartments were built and filled with material of two soils with different texture (a medium textured soil - AR and a clayey soil - AG). During a month and a half a water regime was imposed alternating the irrigation among the compartments. The soil water content in the compartments was measured with TDR and tensiometers. Soil hydraulic properties - retention and conductivity - were analyzed by standard methods. Root density was determined by weighing at the end of the experiment, resulting in values twice as high in AR than in AG soil. It was observed that water extraction occurred preferentially from the lysimeter compartments with the highest matric flux potential. Occasionally, water transfer from the compartment with higher matric flux potential to the lower one was observed, releasing water from root to soil (hydraulic lift). To compensate for the effect of heterogeneity of root distribution and root activity and soil-root contact, an empirical factor f was added to the model. Its value was determined by a numerical fitting procedure aiming at the highest correlation between model and observation in the four lysimeters. The model described 80% of the observations satisfactorily by using these f values, which were 0.01506 and 0.003713, respectively, for AR and AG. Model predic

Marlon Gomes da, Rocha; Leandro Neves, Faria; Derblai, Casaroli; Quirijn de Jong, Van Lier.

199

The Patronage of Thirst: Exploring Institutional Fit on a Divided Cyprus  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We explore the links between Cyprus's colonial past, divided present, and current water scarcity. With reference to the concept of fit, we tackle the question of whether we can observe fit in settings where institutions for collective action work differently than we would expect. We perform a secondary analysis of interview materials on Cyprus's water conflicts, extracting arguments for and against different solutions to water scarcity. Two perspectives on fit emerge: "island fit", ...

Dimitrios Zikos; Matteo Roggero

2013-01-01

200

Layer dividing and zone dividing of physical property of crust and deep structure in Jiangxi province  

International Nuclear Information System (INIS)

On the base of summing experiences both at home and abroad, the Bugar gravitative anomalies are studied by major means of data processing. According to the anomalous character, three layer crust models (surface layer, middle layer in region and material layer under crust) are built up, depth of upper and bottom surfaces for every layer is calculated quantitatively, their varied characters of depth are studied and deep geological tectonics are outlined. The 'density' and 'mass' of every layer are calculated, and according to these two parameters, the shallow geological tectonics are researched. The relation-factor R between the surface altitude and Bugar gravitative anomalies are calculated and the stable or unstable crust zones are divided. The favorable mine zones for uranium deposit in Jiangxi Province are outlined

2001-04-01

 
 
 
 
201

To divide or not to divide: control of the bacterial cell cycle by environmental cues.  

Science.gov (United States)

Whether to divide or not is an important decision that nearly all cells have to make, especially bacteria that are exposed to drastic environmental changes. Under adverse conditions proliferation and growth could compromise cellular integrity and hence must be downregulated. To this end, bacteria have evolved sophisticated mechanisms to transduce environmental information into the cell cycle engine. Recent studies in Escherichia coli, Bacillus subtilis and Caulobacter crescentus indicate that these mechanisms often involve small molecule-based signaling, regulated proteolysis, as well as protein-protein interactions. Most of them delay replication initiation or septum formation by targeting the key regulators DnaA or FtsZ, respectively. Remarkably, while the targets are conserved, the precise mechanisms show a considerable degree of diversity among different species. PMID:24631929

Jonas, Kristina

2014-04-01

202

Procesamiento analógico a partir de elementos altamente resistivos / Analog Processing based on Quasi-Infinite Resistors  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish El presente trabajo propone una técnica para diseñar, a partir de elementos altamente resistivos, circuitos integrados CMOS analógicos tales como amplificadores compensados en offset, filtros sintonizables de baja frecuencia, espejos de corriente programables y generadores de funciones de membresía. [...] La técnica propuesta incorpora transistores operando en la región de inversión débil para reducir los requerimientos de área y las contribuciones de offset, así como para reducir las componentes de ruido y distorsión, mejorando el compromiso exactitud-velocidad-potencia. Éstas características permiten facilitar el acondicionamiento de señales de baja frecuencia y habilitar el diseño de dispositivos con sintonización multidécada de ganancia y frecuencia. Por otro lado, los circuitos propuestos son atractivos para la implementación analógica de arquitecturas reservadas al ámbito digital, tales como filtros adaptables y sistemas difusos, por mencionar algunos, así como dispositivos de procesamiento y acondicionamiento de señal de alta eficiencia. Se reportan caracterizaciones a partir de simulaciones, mediciones y análisis estadísticos de prototipos diseñados con una tecnología CMOS de 0.5|im de largo de canal, dos capas de polisilicio y tres capas de metal. Los resultados obtenidos concuerdan con aquellos anticipados en el diseño de los circuitos. Abstract in english This work proposes a technique for design of CMOS analog integrated circuits such as offset compensated amplifiers, low-frequency filters, programmable current mirrors and membership function generators, based on high-value (quasi-infinite) resistors. The proposed technique incorporates transistors [...] operating in weak-inversion mode in order to reduce the area requirements and minimize the DC-offset. In addition, improvement on both, noise performance and linearity, are achieved along with an enhanced speed-accuracy-power tradeoff. Those features make easier the processing of low-frequency signals and allow the design of systems with multi-decade tunability of gain and frequency. The presented circuits are attractive for implementation of high-accuracy processors for signal conditioning as well as architectures usually reserved to digital approaches, for instance neural networks, adaptive filters, and neuro-fuzzy systems, to mention a few. Characterization through computer simulations, statistical analysis and experimental measurements of prototypes in a double-poly, three metal layers, 0.5pm CMOS technology are reported. The attained results follow the course anticipated in the design of the circuits.

Muñiz-Montero, Carlos; Sánchez-Gaspariano, Luis Abraham; Ponce-Ponce, Víctor Hugo; Aguilar-Jáuregui, María Elena; Espinosa-Sosa, Osvaldo.

203

Comparison of three resistor network division circuits for the readout of 4×4 pixel SiPM arrays  

International Nuclear Information System (INIS)

The purpose of this study is to investigate the behavior of a flexible SensL's silicon photomultiplier array (SPMArray4) photodetector for possible applications in PET imaging. We have designed and evaluated three different resistor network division circuits to read out the signal outputs of a 4×4 pixel SiPM array. We have applied firstly (i) a symmetric resistive voltage division circuit, secondly (ii) a symmetric resistive charge division circuit and thirdly (iii) a charge division multiplexing resistor network reducing the 16 pixel outputs to 4 position signals. In the first circuit the SensL SPMArray4-A0 preamplification electronics and a SPMArray4-A1 evaluation board providing the 16 pixels voltage outputs were used, before the symmetric resistive voltage network. We reduced the 16 voltage signals firstly to 4X and 4Y coordinate signals. Then those signals were further reduced to 2X and 2Y position signals connected via a resistor network. In the second readout circuit we have used the same technique but without the preamplification stage. The third circuit is based on a discretized positioning circuit, which multiplexes the 16 signals from the SiPM array to 4 position signals. The 4 position signals (Xa, Xb, Yc and Yd) were digitized using a free running sampling technique. An FPGA (Spartan 6 LX16) was used for triggering and signal processing of the pulses. We acquired raw images and energy histograms of a BGO and a CsI:Na pixilated scintillator under 22Na excitation. A clear visualization of the discrete 2×2×5 mm3 pixilated BGO scintillator elements as well as the 1×1×5 mm3 pixilated CsI:Na crystal array was achieved with all applied readout circuits. The symmetric resistive charge division circuit provides higher peak to valley ratio than the other readout circuits. ?he sensitivity and the energy resolution remained almost constant for the three circuits

2013-02-21

204

The Digital Divide, framing and mapping the phenomenon  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This chapter explores the global dimension of the Digital Divide. It frames the concept and maps the status and the causes of the phenomenon today. The first part investigates how the Digital Divide can be measured, framing the question and some of the trends foreseen by scholars on the phenomenon. The second part provides the current status of the Digital Divide, mapping the distribution of the usage of the Internet worldwide with some national indicators and measuring how economic factors c...

Calderaro, Andrea

2009-01-01

205

Digital Divide amongst Urban Youths in Malaysia – Myth or Reality?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Digital Divide is an important issue with serious consequences, both for the individuals affected and society. With 90% of youths in urban areas using the Internet, there is a myth that the Digital Divide no longer exists amongst urban youths. Based on a random survey of 1639 youths, this study analyses the possibility of a digital divide along ethnic lines in Malaysia.. Findings indicate there are significant ethnic-based differences in home PC ownership and Internet connection. There ar...

C-h, Patrick Soh; Yap Liang Yan; Tze San Ong; Boon Heng Teh

2012-01-01

206

Use of 1012 and 1013 Ohm resistors in TIMS analysis of Sr and Nd isotopes in sub-nanogram geological and environmental samples  

Science.gov (United States)

Analysis of isotope ratios in small geological and environmental samples such as inclusions in diamonds or individual human hairs is ultimately limited by the detection system of the mass spectrometer. We report a technique using a TRITON Thermal Ionisation Mass-Spectrometer (TIMS) equipped with nine Faraday cups to measure sample sizes up to 10 times smaller than currently feasible. Use of current amplifiers with 1012 Ohm and 1013 Ohm resistors instead of the standard 1011 Ohm resistors promises a 2-3 fold and 4-5 fold improvement in signal to noise ratios, respectively. This improvement results in higher precision on analyses of small ion beams. The precision of measurements of 100 pg Nd and Sr standards is found to be a factor of ~2 better for the 1012 ohm resistors compared to 1011 Ohm resistors (i.e., 2RSE of 64 ppm instead of 110 ppm for a Nd analysis). The reproducibility of the 143Nd/144Nd and 87Sr/86Sr ratios for 100 pg standards using 1012 Ohm resistors is 201 ppm for Nd (2RSD, n=20) and 116 ppm for Sr (2RSD, n=10). Thus, variability in Nd and Sr isotope ratios in the 4th decimal place, e.g. 143Nd/144Nd 0.5110 - 0.5119 or 87Sr/86Sr 0.7100-0.7109, can be resolved in such small samples provided that the procedural blanks and chemical separation are optimal. A miniaturised low-blank chemical separation procedure is currently developed at the Vrije Universiteit Amsterdam. Preliminary data using current amplifiers with 1013 Ohm resistors show that the precision (2SE) on Nd isotope ratios for 143Nd sizes of 40 ?V (~2,500 cps) is 1%, whereas for 1.5 mV (~ 90,000 cps) the 2SE is 480 ppm. The high gain amplifiers can thus potentially be used instead of multi ion counting and/or in the range between ion counting and Faraday cups equipped with the standard 1011 Ohm resistors. Use of the 1013 Ohm resistors is preferred over multiple ion counting systems as potential problems with non-linearity, instability, or the limited dynamic range of the ion counters are avoided. This new methodology thus potentially opens up new applications in a range of studies on small sample sizes. More data using the latest design 1013 Ohm resistors will be presented at the meeting.

Koornneef, J.; Bouman, C.; Schwieters, J.; Davies, G. R.

2012-12-01

207

OSL and TL of Resistors of Mobile Phones for Retrospective Accident Dosimetry  

Energy Technology Data Exchange (ETDEWEB)

Optically stimulated luminescence (OSL) and thermoluminescence (TL) of ubiquitous materials continue to draw wider attention for individual dosimetry in nuclear and radiation accidents. Use of ubiquitous objects for radiation dosimetry is preferred because the affected persons in such unexpected events are usually not covered by personal dosimetry services and do not carry personal dosimeters. Often accident sites do not have area monitoring system in place. As the main concern of the dosimetry is health effects, a quick distinction of level of exposures of the affected persons for the required medical care becomes important in all accidents involving radiation. Both in large scale nuclear accidents such Fukushima, Chernobyl or Hiroshima and Nagasaki where large population around the accident site get exposed to radiation (evacuation is based on doses) and in smaller but panicky events, such as misuse of radiological exposure device (RED), radiological dispersive device (RDD: 'Dirty Bomb'), improvised nuclear device (IND) and deliberate dispersal of radioactive contaminants, a need for an ubiquitous personal dosimeter is well recognized. As biological dosimetry systems are yet to become viable for measurements of doses with required accuracy and speed, use of physical dosimeters is often explored. Among the various types of physical dosimetry systems, use of TL and OSL by processing common material such as bricks or tiles and measuring the doses cumulated for long periods of time has already become an accepted tool for large scale nuclear accidents such as Hiroshima and Nagasaki or Chernobyl involving higher doses. In the other potential cases of unexpected situations where the doses encountered could be much lower (even to escape the range of remotely installed area monitors), the need to measure even the low doses in shortest possible time becomes important. It is often realized that in such situations, the main problem could become the panic at the work place and in the public rather than actual health hazard due to radiation exposure. Therefore, a quick demonstration of measurement of doses following the accident is needed to reassure those receiving insignificant or low level of exposures that they are quite safe and need no treatment. This confidence building also becomes an important aspect of dosimetry. As the ranges of doses which could be encountered in such situations may vary from the background level to significantly high doses depending on the type of accident / incident and the location of personnel, it becomes important that the techniques used in retrospective dosimetry should be very sensitive and should be able to measure doses in a wide range from background level to several Gy. More recently, with the increasing apprehensions of nuclear terrorism / dirty bomb, research and developments in retrospective dosimetry has gained a new momentum the world over. Among the TL and OSL sensitive materials, the extraction and the processing of the materials from bricks and roof tiles is a very time consuming process and gives indirect estimate of individual doses. On the other hand, TL and OSL properties of components of electronic devices mobile phones, i-pods, black-berries, mp3 players and USB sticks containing ceramics with luminescence properties (e.g resistors, capacitors, resonators, antenna switches, transistors etc.) and chip cards containing silica epoxy (e.g. credit cards, bank cards, social security card, telephone card, SIM cards, ID cards e.g) are being considered very attractive and being evaluated. In this study, the TL and OSL properties of the electronic components of mobile phones are investigated and dose recovery potential is evaluated with a presumption that a mobile phone has become a part of body belongings masses of almost ages

Lee, J. I.; Kim, J. L.; Pradhan, A. S.; Chang, I.; Kim, B. H. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2012-05-15

208

OSL and TL of Resistors of Mobile Phones for Retrospective Accident Dosimetry  

International Nuclear Information System (INIS)

Optically stimulated luminescence (OSL) and thermoluminescence (TL) of ubiquitous materials continue to draw wider attention for individual dosimetry in nuclear and radiation accidents. Use of ubiquitous objects for radiation dosimetry is preferred because the affected persons in such unexpected events are usually not covered by personal dosimetry services and do not carry personal dosimeters. Often accident sites do not have area monitoring system in place. As the main concern of the dosimetry is health effects, a quick distinction of level of exposures of the affected persons for the required medical care becomes important in all accidents involving radiation. Both in large scale nuclear accidents such Fukushima, Chernobyl or Hiroshima and Nagasaki where large population around the accident site get exposed to radiation (evacuation is based on doses) and in smaller but panicky events, such as misuse of radiological exposure device (RED), radiological dispersive device (RDD: 'Dirty Bomb'), improvised nuclear device (IND) and deliberate dispersal of radioactive contaminants, a need for an ubiquitous personal dosimeter is well recognized. As biological dosimetry systems are yet to become viable for measurements of doses with required accuracy and speed, use of physical dosimeters is often explored. Among the various types of physical dosimetry systems, use of TL and OSL by processing common material such as bricks or tiles and measuring the doses cumulated for long periods of time has already become an accepted tool for large scale nuclear accidents such as Hiroshima and Nagasaki or Chernobyl involving higher doses. In the other potential cases of unexpected situations where the doses encountered could be much lower (even to escape the range of remotely installed area monitors), the need to measure even the low doses in shortest possible time becomes important. It is often realized that in such situations, the main problem could become the panic at the work place and in the public rather than actual health hazard due to radiation exposure. Therefore, a quick demonstration of measurement of doses following the accident is needed to reassure those receiving insignificant or low level of exposures that they are quite safe and need no treatment. This confidence building also becomes an important aspect of dosimetry. As the ranges of doses which could be encountered in such situations may vary from the background level to significantly high doses depending on the type of accident / incident and the location of personnel, it becomes important that the techniques used in retrospective dosimetry should be very sensitive and should be able to measure doses in a wide range from background level to several Gy. More recently, with the increasing apprehensions of nuclear terrorism / dirty bomb, research and developments in retrospective dosimetry has gained a new momentum the world over. Among the TL and OSL sensitive materials, the extraction and the processing of the materials from bricks and roof tiles is a very time consuming process and gives indirect estimate of individual doses. On the other hand, TL and OSL properties of components of electronic devices mobile phones, i-pods, black-berries, mp3 players and USB sticks containing ceramics with luminescence properties (e.g resistors, capacitors, resonators, antenna switches, transistors etc.) and chip cards containing silica epoxy (e.g. credit cards, bank cards, social security card, telephone card, SIM cards, ID cards e.g) are being considered very attractive and being evaluated. In this study, the TL and OSL properties of the electronic components of mobile phones are investigated and dose recovery potential is evaluated with a presumption that a mobile phone has become a part of body belongings masses of almost ages

2012-05-01

209

Divided Difference Operator for the Highest root Hessenberg variety  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We construct a divided difference operator using GKM theory. This generalizes the classical divided difference operator for the cohomology of the complete flag variety. This construction proves a special case of a recent conjecture of Shareshian and Wachs. Our methods are entirely combinatorial and algebraic, and rely heavily on the combinatorics of root systems and Bruhat order.

Teff, Nicholas

2013-01-01

210

A novel wideband low phase noise 2: 1 frequency divider  

Energy Technology Data Exchange (ETDEWEB)

This paper describes a novel low-power wideband low-phase noise divide-by-two frequency divider. Hereby, a new D-latch topology is introduced. By means of conventional dynamic source-coupled logic techniques, the divider demonstrates a wideband with low phase noise by adding a switch transistor between the clock port and the couple node of the input NMOS pair in the D latch. The chip was fabricated in the 90-nm CMOS process of IBM. The measurement results show that the frequency divider has an input frequency range from 0.05 to 10 GHz and the phase noise is -159.8 dBc/Hz at 1 MHz offset from the carrier. Working at 10 GHz, the frequency divider dissipates a total power of 9.12 mW from a 1.2 V supply while occupying only 0.008 mm{sup 2} of the core die area. (semiconductor integrated circuits)

Lei Xuemei; Wang Zhigong; Wang Keping; Li Wei, E-mail: zgwang@seu.edu.c [Institute of RF- and OE-ICs, Southeast University, Nanjing 210096 (China)

2010-06-15

211

A novel wideband low phase noise 2: 1 frequency divider  

International Nuclear Information System (INIS)

This paper describes a novel low-power wideband low-phase noise divide-by-two frequency divider. Hereby, a new D-latch topology is introduced. By means of conventional dynamic source-coupled logic techniques, the divider demonstrates a wideband with low phase noise by adding a switch transistor between the clock port and the couple node of the input NMOS pair in the D latch. The chip was fabricated in the 90-nm CMOS process of IBM. The measurement results show that the frequency divider has an input frequency range from 0.05 to 10 GHz and the phase noise is -159.8 dBc/Hz at 1 MHz offset from the carrier. Working at 10 GHz, the frequency divider dissipates a total power of 9.12 mW from a 1.2 V supply while occupying only 0.008 mm2 of the core die area. (semiconductor integrated circuits)

2010-06-01

212

Prospective memory: effects of divided attention on spontaneous retrieval.  

Science.gov (United States)

We examined the effects of divided attention on the spontaneous retrieval of a prospective memory intention. Participants performed an ongoing lexical decision task with an embedded prospective memory demand, and also performed a divided-attention task during some segments of lexical decision trials. In all experiments, monitoring was highly discouraged, and we observed no evidence that participants engaged monitoring processes. In Experiment 1, performing a moderately demanding divided-attention task (a digit detection task) did not affect prospective memory performance. In Experiment 2, performing a more challenging divided-attention task (random number generation) impaired prospective memory. Experiment 3 showed that this impairment was eliminated when the prospective memory cue was perceptually salient. Taken together, the results indicate that spontaneous retrieval is not automatic and that challenging divided-attention tasks interfere with spontaneous retrieval and not with the execution of a retrieved intention. PMID:24046252

Harrison, Tyler L; Mullet, Hillary G; Whiffen, Katie N; Ousterhout, Hunter; Einstein, Gilles O

2014-02-01

213

Investigation on powder metallurgy Cr-Si-Ta-Al alloy target for high-resistance thin film resistors with low temperature coefficient of resistance  

International Nuclear Information System (INIS)

The sputtering target for high-resistance thin film resistors plays a decisive role in temperature coefficient of resistance (TCR). Silicon-rich chromium (Cr)-silicon (Si) target was designed and smelted for high-resistance thin film resistors with low TCR. Valve metal tantalum (Ta) and aluminum (Al) were introduced to the Cr-Si target to improve the performance of the target prepared. The measures for grain refining in smelting Cr-Si-Ta-Al target were taken to improve the performance of the prepared target. The mechanism and role of grain refinement were discussed in the paper. The phase structure of the prepared target was detected by X-ray diffraction (XRD). Rate of temperature drop was studied to reduce the internal stress of alloy target and conquer the easy cracking disadvantage of silicon-rich target. The electrical properties of sputtered thin film resistors were tested to evaluate the performance of the prepared target indirectly.

2010-03-01

214

Social Support Quality in Internet Based Information and Communication: From "Digital Divide" to "Voice Divide"  

Directory of Open Access Journals (Sweden)

Full Text Available National and international studies demonstrate that the number of teenagers using the inter-net increases. But even though they actually do have access from different places to the in-formation and communication pool of the internet, there is evidence that the ways in which teenagers use the net - regarding the scope and frequency in which services are used as well as the preferences for different contents of these services - differ significantly in relation to socio-economic status, education, and gender. The results of the regarding empirical studies may be summarised as such: teenager with low (formal education especially use internet services embracing 'entertainment, play and fun' while higher educated teenagers (also prefer intellectually more demanding and particularly services supplying a greater variety of communicative and informative activities. More generally, pedagogical and sociological studies investigating "digital divide" in a dif-ferentiated and sophisticated way - i.e. not only in terms of differences between those who do have access to the Internet and those who do not - suggest that the internet is no space beyond 'social reality' (e.g. DiMaggio & Hargittai 2001, 2003; Vogelgesang, 2002; Welling, 2003. Different modes of utilisation, that structure the internet as a social space are primarily a specific contextualisation of the latter - and thus, the opportunities and constraints in virtual world of the internet are not less than those in the 'real world' related to unequal distribu-tions of material, social and cultural resources as well as social embeddings of the actors involved. This fact of inequality is also true regarding the outcomes of using the internet. Empirical and theoretical results concerning forms and processes of networking and commu-nity building - i.e. sociability in the internet, as well as the social embeddings of the users which are mediated through the internet - suggest that net based communication and infor-mation processes may entail the resource 'social support'. Thus, with reference to social work and the task of compensating the reproduction of social disadvantages - whether they are medial or not - the ways in which teenagers get access to and utilize net based social sup-port are to be analysed.

2004-05-01

215

Effects of resistors and capacitors inserted between wires and chip bonding pads on current-voltage characteristics of series junction arrays  

International Nuclear Information System (INIS)

Series Nb/AlO x/Nb junction array circuits are commonly used for evaluation of a critical current (I c) spread as an important parameter on Nb-based LSI chips. We present a junction array circuit suitable for accurate evaluation of the spread. The circuit has a tolerance for the I c suppression caused by external noises and synchronous switching which are often observed in measurements. Key elements of the circuit are the low value resistors, large value capacitors, and high value resistors inserted between wires and chip bonding pads. This paper describes effects of these key elements on current-voltage characteristics of junction arrays

2005-10-01

216

On locally divided integral domains and CPI-overrings  

Digital Repository Infrastructure Vision for European Research (DRIVER)

It is proved that an integral domain R is locally divided if and only if each CPI-extension of ℬ (in the sense of Boisen and Sheldon) is R-flat (equivalently, if and only if each CPI-extension of R is a localization of R). Thus, each CPI-extension of a locally divided domain is also locally divided. Treed domains are characterized by the going-down behavior of their CPI-extensions. A new class of (not necessarily treed) domains, called CPI-closed domains, is introduced. Examples i...

Dobbs, David E.

1981-01-01

217

Comparison of three resistor network division circuits for the readout of 4×4 pixel SiPM arrays  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this study is to investigate the behavior of a flexible SensL's silicon photomultiplier array (SPMArray4) photodetector for possible applications in PET imaging. We have designed and evaluated three different resistor network division circuits to read out the signal outputs of a 4×4 pixel SiPM array. We have applied firstly (i) a symmetric resistive voltage division circuit, secondly (ii) a symmetric resistive charge division circuit and thirdly (iii) a charge division multiplexing resistor network reducing the 16 pixel outputs to 4 position signals. In the first circuit the SensL SPMArray4-A0 preamplification electronics and a SPMArray4-A1 evaluation board providing the 16 pixels voltage outputs were used, before the symmetric resistive voltage network. We reduced the 16 voltage signals firstly to 4X and 4Y coordinate signals. Then those signals were further reduced to 2X and 2Y position signals connected via a resistor network. In the second readout circuit we have used the same technique but without the preamplification stage. The third circuit is based on a discretized positioning circuit, which multiplexes the 16 signals from the SiPM array to 4 position signals. The 4 position signals (Xa, Xb, Yc and Yd) were digitized using a free running sampling technique. An FPGA (Spartan 6 LX16) was used for triggering and signal processing of the pulses. We acquired raw images and energy histograms of a BGO and a CsI:Na pixilated scintillator under {sup 22}Na excitation. A clear visualization of the discrete 2×2×5 mm{sup 3} pixilated BGO scintillator elements as well as the 1×1×5 mm{sup 3} pixilated CsI:Na crystal array was achieved with all applied readout circuits. The symmetric resistive charge division circuit provides higher peak to valley ratio than the other readout circuits. ?he sensitivity and the energy resolution remained almost constant for the three circuits.

Stratos, David [Department of Medical Instruments Technology, Technological Educational Institute of Athens (Greece); Maria, Georgiou [Department of Medical Instruments Technology, Technological Educational Institute of Athens (Greece); Department of Nuclear Medicine, Medical School, University of Thessaly (Greece); Eleftherios, Fysikopoulos [Department of Medical Instruments Technology, Technological Educational Institute of Athens (Greece); School of Electrical and Computer Engineering, National Technical University of Athens, Athens (Greece); George, Loudos, E-mail: gloudos@teiath.gr [Department of Medical Instruments Technology, Technological Educational Institute of Athens (Greece)

2013-02-21

218

Annan warns of 'content divide' between rich and poor  

CERN Document Server

"The Secretary-General of the United Nations, Kofi Annan, warned today (10 December) that a "content divide" is threatening to deprive developing countries of the full benefits offered by information and communications technologies (ICTs)" (1 page)

Dickson, D

2003-01-01

219

On locally divided integral domains and CPI-overrings  

Directory of Open Access Journals (Sweden)

Full Text Available It is proved that an integral domain R is locally divided if and only if each CPI-extension of ℬ (in the sense of Boisen and Sheldon is R-flat (equivalently, if and only if each CPI-extension of R is a localization of R. Thus, each CPI-extension of a locally divided domain is also locally divided. Treed domains are characterized by the going-down behavior of their CPI-extensions. A new class of (not necessarily treed domains, called CPI-closed domains, is introduced. Examples include locally divided domains, quasilocal domains of Krull dimension 2, and qusilocal domains with the QQR-property. The property of being CPI-closed behaves nicely with respect to the D+M construction, but is not a local property.

David E. Dobbs

1981-03-01

220

Digital Divide between Teachers and Students in Urban Bangladesh  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Telecom boom since 2000 and ‘Digital Bangladesh’ campaign since late 2008 created significant nationwide hype, resulting rapid increase in the use of digital devices. While studies are being conducted to use the ability of “power users of technology” for reducing digital divide, there is hardly any data available on them in Bangladesh context. A study was conducted to study the digital divide and ICT usage pattern among the urban students and teachers of schools and colleges in Dhaka,...

Khalid, Md Saifuddin

2011-01-01

 
 
 
 
221

Digital Divide between Teachers and Students in Urban Bangladesh  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Telecom boom since 2000 and ‘Digital Bangladesh’ campaign since late 2008 created significant nationwide hype, resulting rapid increase in the use of digital devices. While studies are being conducted to use the ability of “power users of technology” for reducing digital divide, there is hardly any data available on them in Bangladesh context. A study was conducted to study the digital divide and ICT usage pattern among the urban students and teachers of schools and colleges in Dhaka,...

Khalid, Md Saifuddin

2012-01-01

222

Afterword. Internet Freedom, Nuanced Digital Divide, and the Internet Craftsman  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This book provides an in-depth comparative analysis of inequality and the stratification of the digital sphere. Grounded in classical sociological theories of inequality, as well as empirical evidence, this book defines 'the digital divide' as the unequal access and utility of internet communications technologies and explores how it has the potential to replicate existing social inequalities, as well as create new forms of stratification. The Digital Divide examines how various demographic an...

Meinrath, Sascha D.; Losey, James; Lennett, Benjamin

2013-01-01

223

Wireless Technologies Bridging the Digital Divide in Education  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The objective of this paper is to demonstrate how the latest wireless standards and technologies may overcome the digital divide in education in the developed and developing worlds. The concept of the digital divide is discussed in the traditional socio-economic sense and expanded in terms of the learner's location, age, culture and background. It is important that we understand the full extent and complexities of this division if we are to effectively bridge it. Why and how the digital div...

Gerard Smyth

2006-01-01

224

INTERNET PARADOX: DEFINING MEDIA GLOBALIZATION AND THE DIGITAL DIVIDE.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Although media globalization has created the capability of mass population to connect through barrier space previously not possible, a downside of this revolution exists. A digital divide is in place. The language of digital divide not only place the people into simplistic ‘have/have nots’ categories, making assumptions about the solution to information poverty with little attention to less and less connected, educated and privileged of developing countries. The aim of the present paper i...

2005-01-01

225

Ion-implanted capacitively coupled silicon strip detectors with integrated polysilicon bias resistors processed on a 100 mm wafer  

International Nuclear Information System (INIS)

Double-sided silicon strip detectors with integrated coupling capacitors and polysilicon resistors have been processed on a 100 mm wafer. A detector with an active area of 19x19 mm2 was connected to LSI readout electronics and tested. The strip pitch of the detector is 25 ?m on the p-side and 50 ?m on the n-side. The readout pitch is 50 ?m on both sides. The number of readout strips is 774 and the total number of strips is 1161. On the p-side a signal-to-noise of 35 has been measured using a 90Sr ?-source. The n-side has been studied using a laser. (orig.)

1991-12-15

226

Ion-implanted capacitively coupled silicon strip detectors with integrated polysilicon bias resistors processed on a 100 mm wafer  

Energy Technology Data Exchange (ETDEWEB)

Double-sided silicon strip detectors with integrated coupling capacitors and polysilicon resistors have been processed on a 100 mm wafer. A detector with an active area of 19x19 mm{sup 2} was connected to LSI readout electronics and tested. The strip pitch of the detector is 25 {mu}m on the p-side and 50 {mu}m on the n-side. The readout pitch is 50 {mu}m on both sides. The number of readout strips is 774 and the total number of strips is 1161. On the p-side a signal-to-noise of 35 has been measured using a {sup 90}Sr {beta}-source. The n-side has been studied using a laser. (orig.).

Hietanen, I.; Lindgren, J.; Orava, R.; Tuuva, T.; Voutilainen, M. (Univ. Helsinki (Finland)); Brenner, R. (Aabo Akademi, Turku (Finland)); Andersson, M.; Leinonen, K.; Ronkainen, H. (Technical Research Centre of Finland, Espoo (Finland))

1991-12-15

227

Characterization of the first prototypes of Silicon Photomultipliers with bulk-integrated quench resistor fabricated at MPI semiconductor laboratory  

International Nuclear Information System (INIS)

In this paper new results of the characterization of Silicon Photomultipliers (SiPMs) with bulk-integrated quench resistor will be presented. The novel detector concept was developed at the Max-Planck-Institute (MPI) semiconductor laboratory and allows a metal and polysilicon free entrance window which offers an improvement in photon detection efficiency (PDE). For electrical separation and suppression of optical cross talk (OCT) an insensitive area (gap) between neighboring cells is required. Based on simulations the first prototypes with devices of different combinations of cell size and gap were fabricated, providing the opportunity to study the influence of these parameters on the detector performance. First PDE measurements of the new detector are presented together with results of the influence of geometrical variations. Also an outlook on possible future developments of the concept with single cell read-out is given

2013-08-01

228

Characterization of the first prototypes of Silicon Photomultipliers with bulk-integrated quench resistor fabricated at MPI semiconductor laboratory  

Energy Technology Data Exchange (ETDEWEB)

In this paper new results of the characterization of Silicon Photomultipliers (SiPMs) with bulk-integrated quench resistor will be presented. The novel detector concept was developed at the Max-Planck-Institute (MPI) semiconductor laboratory and allows a metal and polysilicon free entrance window which offers an improvement in photon detection efficiency (PDE). For electrical separation and suppression of optical cross talk (OCT) an insensitive area (gap) between neighboring cells is required. Based on simulations the first prototypes with devices of different combinations of cell size and gap were fabricated, providing the opportunity to study the influence of these parameters on the detector performance. First PDE measurements of the new detector are presented together with results of the influence of geometrical variations. Also an outlook on possible future developments of the concept with single cell read-out is given.

Jendrysik, Christian, E-mail: jendrysik@hll.mpg.de [Max-Planck-Institut Halbleiterlabor, Otto-Hahn-Ring 6, D-81739 Munich (Germany); Max-Planck-Institut für Physik, Föhringer Ring 6, D-80805 Munich (Germany); Andri?ek, Ladislav; Liemann, Gerhard; Moser, Hans-Günther; Ninkovi?, Jelena; Richter, Rainer [Max-Planck-Institut Halbleiterlabor, Otto-Hahn-Ring 6, D-81739 Munich (Germany); Max-Planck-Institut für Physik, Föhringer Ring 6, D-80805 Munich (Germany); Schopper, Florian [Max-Planck-Institut Halbleiterlabor, Otto-Hahn-Ring 6, D-81739 Munich (Germany); Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, D-85748 Garching (Germany)

2013-08-01

229

The classical Starling resistor model often does not predict inspiratory airflow patterns in the human upper airway.  

Science.gov (United States)

The upper airway is often modeled as a classical Starling resistor, featuring a constant inspiratory airflow, or plateau, over a range of downstream pressures. However, airflow tracings from clinical sleep studies often show an initial peak before the plateau. To conform to the Starling model, the initial peak must be of small magnitude or dismissed as a transient. We developed a method to simulate fast or slow inspirations through the human upper airway, to test the hypothesis that this initial peak is a transient. Eight subjects [4 obstructive sleep apnea (OSA), 4 controls] slept in an "iron lung" and wore a nasal mask connected to a continuous/bilevel positive airway pressure machine. Downstream pressure was measured using an epiglottic catheter. During non-rapid eye movement (NREM) sleep, subjects were hyperventilated to produce a central apnea, then extrathoracic pressure was decreased slowly (?2-4 s) or abruptly (<0.5 s) to lower downstream pressure and create inspiratory airflow. Pressure-flow curves were constructed for flow-limited breaths, and slow vs. fast reductions in downstream pressure were compared. All subjects exhibited an initial peak and then a decrease in flow with more negative pressures, demonstrating negative effort dependence (NED). The rate of change in downstream pressure did not affect the peak to plateau airflow ratio: %NED 22 ± 13% (slow) vs. 20 ± 5% (fast), P = not significant. We conclude that the initial peak in inspiratory airflow is not a transient but rather a distinct mechanical property of the upper airway. In contrast to the classical Starling resistor model, the upper airway exhibits marked NED in some subjects. PMID:24458746

Owens, Robert L; Edwards, Bradley A; Sands, Scott A; Butler, James P; Eckert, Danny J; White, David P; Malhotra, Atul; Wellman, Andrew

2014-04-01

230

Age differences in divided attention in a simulated driving task.  

Science.gov (United States)

The ability of young, middle-aged, and old adults to divide attention was examined using a dual task experiment involving two continuous performance tasks. The first task was a compensatory tracking task modeled after the important everyday activity of car driving. The second task was a self-paced visual choice-reaction time task requiring analysis of a small visual display presented in such a way that no eye movements were required when the two tasks had to be performed simultaneously. Single-task difficulty was individually adjusted for each subject. Performance-Operating-Characteristics were used to control for individual differences in attention allocation strategies. Even when individual differences in single task performance were adequately controlled for, elderly adults showed a significantly decreased ability to divide attention when compared with young and middle-aged adults. Young and middle-aged adults did not differ in the ability to divide attention. PMID:3183311

Ponds, R W; Brouwer, W H; van Wolffelaar, P C

1988-11-01

231

Dividing Cells Regulate Their Lipid Composition and Localization  

Science.gov (United States)

Summary Although massive membrane rearrangements occur during cell division, little is known about specific roles that lipids might play in this process. We report that the lipidome changes with the cell cycle. LC-MS-based lipid profiling shows that 11 lipids with specific chemical structures accumulate in dividing cells. Using AFM, we demonstrate differences in the mechanical properties of live dividing cells and their isolated lipids relative to nondividing cells. In parallel, systematic RNAi knockdown of lipid biosynthetic enzymes identified enzymes required for division, which highly correlated with lipids accumulated in dividing cells. We show that cells specifically regulate the localization of lipids to midbodies, membrane-based structures where cleavage occurs. We conclude that cells actively regulate and modulate their lipid composition and localization during division, with both signaling and structural roles likely. This work has broader implications for the active and sustained participation of lipids in basic biology.

Atilla-Gokcumen, G. Ekin; Muro, Eleonora; Relat-Goberna, Josep; Sasse, Sofia; Bedigian, Anne; Coughlin, Margaret L.; Garcia-Manyes, Sergi; Eggert, Ulrike S.

2014-01-01

232

Ouroboros: A Tool for Building Generic, Hybrid, Divide& Conquer Algorithms  

Energy Technology Data Exchange (ETDEWEB)

A hybrid divide and conquer algorithm is one that switches from a divide and conquer to an iterative strategy at a specified problem size. Such algorithms can provide significant performance improvements relative to alternatives that use a single strategy. However, the identification of the optimal problem size at which to switch for a particular algorithm and platform can be challenging. We describe an automated approach to this problem that first conducts experiments to explore the performance space on a particular platform and then uses the resulting performance data to construct an optimal hybrid algorithm on that platform. We implement this technique in a tool, ''Ouroboros'', that automatically constructs a high-performance hybrid algorithm from a set of registered algorithms. We present results obtained with this tool for several classical divide and conquer algorithms, including matrix multiply and sorting, and report speedups of up to six times achieved over non-hybrid algorithms.

Johnson, J R; Foster, I

2003-05-01

233

Acoustic tool for leak inspections in steam generator divider plates  

International Nuclear Information System (INIS)

Cross flow leakage through divider plates in the primary head of steam generators, may be a contributor to RIHT rise which can have a negative effect on the operation of a plant. A method to provide quick and reliable inspection of divider plate leakage can be very useful in helping make timely and effective maintenance decisions. A novel acoustic tool for performing inspections in drained steam generators during shutdowns has been developed by OH Technologies and successfully demonstrated in a field application. The technique, referred as ALIS (acoustic leak inspection system), performs a scan of the divider plate face and presents a graphic image of the leakage paths and an estimate of the total leakage area. (author)

1997-11-16

234

Bruce NGS A Unit 4 preheater divider plate failure  

International Nuclear Information System (INIS)

On May 19, 1995, without any prior operational indications, Bruce A discovered preheater divider plate damage in Unit 4 that had the potential to have a major impact on the continued safe operation of the station. Further investigations indicated that Unit 4 may have been operating with this damage for as long as ten years. In the two months following the discovery, Bruce A has procured and replaced the 4 divider plates, located most of the missing pieces, retrieved pieces from the PHT system, investigated historical operational information, performed detailed analytical investigations, investigated root cause, performed in-situ and mock-up testing, updated operational procedures and installed DP monitoring equipment

1995-11-19

235

Development of a new lower hybrid antenna module using a poloidal power divider  

Energy Technology Data Exchange (ETDEWEB)

The antenna using poloidal power divider is an effective method for simplification of Lower Hybrid Current Drive (LHCD) antenna system. This method should allow to reduce the power density in the antenna while maintaining a good flexibility of N{sub parallel} spectrum of waves. For this purpose, three types of poloidal power divider which split the power in three, and the 3 x 6 multi-junction module were developed. r.f. properties and outgassing of these components were evaluated using the CEA Cadarache RF Test Facility. A good power dividing ratio of 33 {+-} 4% was obtained for each of these poloidal dividers, and the reflection coefficient was lower value than 1.5%. For the 3 x 6 multi-junction, reflection coefficient was less than 1.3% and r.f. losses lower than 1.0% were measured. On the other hand, it was found in the scattering matrix analysis that reflection coefficient at plasma has to be less than a few % in order to operate these components under available conditions. In combination with two poloidal power dividers connected to the 3 x 6 multi-junction module, quasi stationary operation for r.f. injection time of 1000 sec at 300 kW was demonstrated under water cooling. In this case, it was found that the outgassing rate is in the lower range of 10{sup -7}Pam{sup 3}s{sup -1}m{sup -2} within the maximum module temperature of {approx}100degC. This report describes the experimental and analytical results of a new lower hybrid (LH) antenna module using the poloidal power divider. (author)

Maebara, Sunao; Seki, Masami; Suganuma, Kazuaki [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment] [and others

1996-07-01

236

Water  

Science.gov (United States)

... to drink more water Other drinks How much water do you need? top Water is very important, ... you probably need more water. What about bottled water? top Some people like bottled water for its ...

237

West Antarctic Ice Sheet (WAIS) Divide: Modeling our Future Climate  

Science.gov (United States)

In this video, students see how data from the ice core record is used to help scientists predict the future of our climate. Video features ice cores extracted from the WAIS Divide, a research station on the West Antarctic Ice Sheet.

Foundation, National S.; Core, Wais D.

238

Using Bloom To Bridge the WAC/WID Divide.  

Science.gov (United States)

A longitudinal study combined Stephen Tsuchdi's Workaday activities with Bloom's taxonomy of educational objectives to bridge the WAC/WID (writing across the curriculum/writing in the disciplines) divide. The researchers hoped that by combining concrete activities that can be applied across disciplines with a Bloomian conceptual framework of…

Cross, Geoffrey; Wills, Katherine

239

Dividing Attention Lowers Children's but Increases Adults' False Memories  

Science.gov (United States)

The present study examined the impact of divided attention on children's and adults' neutral and negative true and false memories in a standard Deese/Roediger-McDermott paradigm. Children (7- and 11-year-olds; n = 126) and adults (n = 52) received 5 neutral and 5 negative Deese/Roediger-McDermott word lists; half of each group also received a…

Otgaar, Henry; Peters, Maarten; Howe, Mark L.

2012-01-01

240

Response Styles and the Rural-Urban Divide  

Science.gov (United States)

This article investigates the effect of the rural-urban divide on mean response styles (RSs) and their relationships with the sociodemographic characteristics of the respondents. It uses the Representative Indicator Response Style Means and Covariance Structure (RIRSMACS) method and data from Guyana--a developing country in the Caribbean. The…

Thomas, Troy D.; Abts, Koen; Vander Weyden, Patrick

2014-01-01

 
 
 
 
241

Closing the divide: diverse populations and cancer survivorship.  

Science.gov (United States)

Currently, there is a "divide" between cancer survivorship initiatives and minority participation. The level of participation is nearly nonexistent in many cancer support and control initiatives. Cancer survivorship resources that facilitate access to treatment, psychosocial interventions, clinical trials, and research are key components to eliminating this divide. Differences in cancer results among minority populations are caused by several factors, including biologic reactions to environmental activities, socioeconomic status, perceived beliefs and notions of medical professionals, a lack of resources to participate in cancer support groups, and having personal contact with cancer survivors. Health professionals, advocates, and researchers hold the key to opening more opportunities for the improvement of cancer survivorship among minorities. The belief that "one size fits all" is unrealistic. These beliefs can influence participation in innovative clinical trials, decisions about treatment, emotional responses, and social support relationships. To help ensure participation in these programs, researchers and health workers must understand the role of social and psychosocial implications and results of the assessment, strategies, and sustainability that must be included in the development stage of any cancer support and survivorship initiatives. For this article, the authors examined mechanisms that can be used by cancer-control researchers and program staff to limit the divide between cancer survivorship initiatives and minority participation. They identified three strategies that must be used to address this divide effectively: the inclusion of minorities in clinical trials, intervention studies, treatment, and research programs; the development of culturally sensitive environments; and the ability to sustain minority participation. In summary, cancer survivorship includes many components that are developed individually and collectively to formulate sound strategies for including minorities in cancer-control initiatives. These programs should go beyond basic support groups and should include research studies, clinical trials, and alternative treatments for increasing cancer survival rates and quality of life among minorities. The divide can be addressed only through a proactive initiative that brings cancer survivorship initiatives and minority communities together in full partnership. PMID:16258930

Guidry, Jeffrey Joseph; Torrence, Will; Herbelin, Sarah

2005-12-01

242

Area and Power Optimization of Flexible Multiband Divider  

Directory of Open Access Journals (Sweden)

Full Text Available The demand for lower cost, lower power, and multiband RF circuits increased in conjunction with need of higher level of integration. In this project a low-power single-phase clock multiband flexible divider for Bluetooth, Zigbee, and Network standard’s 802.15.4 and 802.11 a/b/g Wireless LAN frequency synthesizers is proposed based on pulse-swallow topology and is implemented. The frequency synthesizer, usually implemented by a phase-locked loop (PLL, is one of the power-hungry blocks in the RF front-end and the first-stage frequency divider consumes a large portion of power in a frequency synthesizer. The proposed prescaler based approach reduces the area and power significantly. The multiband divider consists of a proposed wideband multi modulus 32/33/47/48 prescaler and an improved bit-cell for swallow (S counter and can divide the frequencies in the three bands of 2.41–2.483 GHz, 5.14–5.30 GHz, and 5.715–5.815 GHz with a resolution selectable from 1 to 25 MHz The proposed multiband flexible divider is silicon verified and consumes power of 0.96 and 2.2 mw in 2.3-and 5-GHz bands, respectively, when operated at 1.8-V power supply. The proposed prescaler is achieved by without using any additional flip flops. It gives a solution to the low power PLL synthesizers for wide range of communication applications.

R.Naveenkumar

2013-12-01

243

Water  

Science.gov (United States)

... drinking water by consuming only bottled water or water from a filtration system that has been certified by an independent ... 15 ppb, CDC recommends using bottled water or water from a filtration system that has been certified by an independent ...

244

Thermosetting polyimide resin matrix composites with interpenetrating polymer networks for precision foil resistor chips based on special mechanical performance requirements  

Science.gov (United States)

Based on interpenetrating networks (IPNs) different macromolecular materials such as epoxy, phenolic, and silicone resin were chosen to modify thermosetting polyimide (TSPI) resin to solve the lack of performance when used for protecting precision foil resistor chips. Copolymerization modification, controlled at curing stage, was used to prepare TSPI composites considering both performance and process requirements. The mechanical properties related to trimming process were mainly studied due to the special requirements of the regularity of scratch edges caused by a tungsten needle. The analysis on scratch edges reveals that the generation and propagation of microcracks caused by scratching together with crack closure effect may lead to regular scratch traces. Experiments show that the elongation at break of TSPI composites is the main reason that determines the special mechanical properties. The desired candidate materials should have proper hardness and toughness, and the specific mechanical data are that the mean elongation at break and tensile strength of polymer materials are in the range of 9.2-10.4% and 100-107 MPa, respectively. Possible reasons for the effect of the modifiers chosen on TSPI polymers, the reaction mechanisms on modified TSPI resin and the IPN structure in TSPI composite polymers were discussed based on IR and TG analysis.

Wang, X. Y.; Ma, J. X.; Li, C. G.; Wang, H. X.

2014-04-01

245

Trigonometrical sums connected with the chiral Potts model, Verlinde dimension formula, two-dimensional resistor network, and number theory  

Science.gov (United States)

We have recently developed methods for obtaining exact two-point resistance of the complete graph minus N edges. We use these methods to obtain closed formulas of certain trigonometrical sums that arise in connection with one-dimensional lattice, in proving Scott's conjecture on permanent of Cauchy matrix, and in the perturbative chiral Potts model. The generalized trigonometrical sums of the chiral Potts model are shown to satisfy recursion formulas that are transparent and direct, and differ from those of Gervois and Mehta. By making a change of variables in these recursion formulas, the dimension of the space of conformal blocks of SU(2) and SO(3) WZW models may be computed recursively. Our methods are then extended to compute the corner-to-corner resistance, and the Kirchhoff index of the first non-trivial two-dimensional resistor network, 2×N. Finally, we obtain new closed formulas for variant of trigonometrical sums, some of which appear in connection with number theory.

Chair, Noureddine

2014-02-01

246

Trigonometrical sums connected with the chiral Potts model, Verlinde dimension formula, two-dimensional resistor network, and number theory  

Energy Technology Data Exchange (ETDEWEB)

We have recently developed methods for obtaining exact two-point resistance of the complete graph minus N edges. We use these methods to obtain closed formulas of certain trigonometrical sums that arise in connection with one-dimensional lattice, in proving Scott’s conjecture on permanent of Cauchy matrix, and in the perturbative chiral Potts model. The generalized trigonometrical sums of the chiral Potts model are shown to satisfy recursion formulas that are transparent and direct, and differ from those of Gervois and Mehta. By making a change of variables in these recursion formulas, the dimension of the space of conformal blocks of SU(2) and SO(3) WZW models may be computed recursively. Our methods are then extended to compute the corner-to-corner resistance, and the Kirchhoff index of the first non-trivial two-dimensional resistor network, 2×N. Finally, we obtain new closed formulas for variant of trigonometrical sums, some of which appear in connection with number theory. -- Highlights: • Alternative derivation of certain trigonometrical sums of the chiral Potts model are given. • Generalization of these trigonometrical sums satisfy recursion formulas. • The dimension of the space of conformal blocks may be computed from these recursions. • Exact corner-to-corner resistance, the Kirchhoff index of 2×N are given.

Chair, Noureddine, E-mail: n.chair@ju.edu.jo

2014-02-15

247

Trigonometrical sums connected with the chiral Potts model, Verlinde dimension formula, two-dimensional resistor network, and number theory  

International Nuclear Information System (INIS)

We have recently developed methods for obtaining exact two-point resistance of the complete graph minus N edges. We use these methods to obtain closed formulas of certain trigonometrical sums that arise in connection with one-dimensional lattice, in proving Scott’s conjecture on permanent of Cauchy matrix, and in the perturbative chiral Potts model. The generalized trigonometrical sums of the chiral Potts model are shown to satisfy recursion formulas that are transparent and direct, and differ from those of Gervois and Mehta. By making a change of variables in these recursion formulas, the dimension of the space of conformal blocks of SU(2) and SO(3) WZW models may be computed recursively. Our methods are then extended to compute the corner-to-corner resistance, and the Kirchhoff index of the first non-trivial two-dimensional resistor network, 2×N. Finally, we obtain new closed formulas for variant of trigonometrical sums, some of which appear in connection with number theory. -- Highlights: • Alternative derivation of certain trigonometrical sums of the chiral Potts model are given. • Generalization of these trigonometrical sums satisfy recursion formulas. • The dimension of the space of conformal blocks may be computed from these recursions. • Exact corner-to-corner resistance, the Kirchhoff index of 2×N are given

2014-02-01

248

Interaction of RuO2 and Lead-Silicate Glass in Thick-Film Resistors  

Directory of Open Access Journals (Sweden)

Full Text Available Results of investigation of X-ray diffraction, infrared and optical spectra of powders of the ruthenium dioxide, lead-silicate glass as well as their mixture before and after sintering are reported. Sintering conditions typical for thick film resistors were used. Intensity of main lines of RuO2 in X-ray diffraction patterns of sintered mixtures decreases and they slightly shift towards small angles. No new reflexes appear in these patterns. Absorbance of RuO2 in the range of 2.5-100 ?m is proportional to and featureless. Infrared spectrum of lead-silicate glass has absorption bands of [SiO4]4- tetrahedra and Pb-O bonds only. Optical spectrum of RuO2 has wide absorption bands at 950 and 370 nm. Spectra of the mixture of RuO2 and glass powders before and after sintering are different indicating that there is interaction between them during the sintering process. Concentration of free charge carriers estimated from the optical spectra is about 1021 cm-3.

Gulmurza Abdurakhmanov

2011-02-01

249

Effects of installed system dumping resistors on stability of open cycle disk type MHD generator connected to power transmission line  

Energy Technology Data Exchange (ETDEWEB)

This study is performed as part of the wide research on large scale coal fired MHD generation systems. Faults in the power transmission line give remarkable fluctuations to the MHD generator and to the transmission network. Then, it is required to take countermeasures for stable operation of the generation system. The fluctuations do not converge to a stable state after cutting off the fault line in the transmission line because the commutation failure occurs in the inverter system after the line faults. The effects of installed system dumping resistors (SDR) on the stability of an open cycle disk type MHD generator connected to power transmission lines are numerically studied. Usually the AC SDR is installed in the AC primary grid of the transmission line for system stability. The SDR is used to absorb the output energy of the synchronous generator and to get stability of the power transmission system when faults occur in the transmission line. In this paper, The authors propose to install the SDR in the DC lines between the MHD generator and the primary side of connected line commutated inverters. It is shown that the SDR is effective for system stability by a. time dependent numerical analysis. This study makes it clear that switching on the applied SDR using the thyristor switches in addition to cutting off the faulted transmission lines is effective to remove the fluctuations of the MHD generation system.

Hayanose, N.; Inui, Y.; Ishikawa, M. [Kobe City College of Technology, Kobe (Japan). Dept. of Electrical Engineering

2001-07-01

250

A new mechanism to cross the phantom divide  

CERN Document Server

Recently, type Ia supernovae data appear to support a dark energy whose equation of state $w$ crosses $-1$, which is a much more amazing problem than the acceleration of the universe. We show that it is possible for the equation of state to cross the phantom divide by only a single scalar field in the gravity with an additional inverse power-law term of Ricci scalar in the Lagrangian. The necessary and sufficient condition for a universe in which the dark energy can cross the phantom divide is obtained. Some analytical solutions with $w-1$ are obtained. A minimal coupled scalar with different potentials, including quadratic, cubic, quantic, exponential and logarithmic potentials are investigated via numerical methods, respectively. All these potentials lead to the crossing behavior. We show that it is a general geometric result which is independent on the concrete form of the potential of the scalar.

Du, Yunshuang; Li, Xin-Zhou

2010-01-01

251

Traffic Prediction Based on SVM Training Sample Divided by Time  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In recent years, the volume of traffic is rapidly increasing. When vehicles running through the tunnel are more intensive or move slowly, the tunnel environment occurs deteriorated sharply, which affects the normal operation of the vehicle in the tunnel. This paper uses the result of previous mining association rules to select feature items and to establish four training samples divided by time. Then the training samples are utilized to create the SVM classification model. Finally the trained...

Lingli Li; Hongxia Xia; Lin Li; Qingbo Wang

2013-01-01

252

Single versus divided doses of sintamil in depression  

Directory of Open Access Journals (Sweden)

Full Text Available Fifty one out-patient depressives were treated with Sintamil for a 5 week trial period under double-blind conditions. Sintamil 75 mg/day was administered in a fixed dosage schedule either as a single daily dose (SDS or in 3 divided doses (DDS. There were no significant differences between the two treatment modali-ties in so far as efficacy was concerned. The SDS regimen of drug administration was associated with a lesser incidence of side effects.

Doongaji D

1977-01-01

253

Job quality in Europe: the North-South divide  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper examines the job quality in Europe. It is based on the results of the Fourth European Foundation Survey on working conditions covering different dimensions including work organisation, job content, autonomy at work, aspects of worker dignity, working time and work-life balance, working conditions and safety in the workplace. The results point to the existence of great diversity in the job quality across Europe and the north-south divide. The job quality differences are related to t...

2008-01-01

254

Trope Theory on the Mental/Physical Divide  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In our everyday discourse, we distinguish without fail between minds and bodies or between the mental and the physical. Yet, in philosophy there is a tendency to get rid of this divide. Roughly, the naturalist wants to reduce or to identify the mental with the physical in order to provide a unified basis for scientific research. The idealist, in contrast, sticks to the mental as a precondition of grasping the physical. The physical then tends to turn into mere mental r...

Trettin, Ka?the

2002-01-01

255

Crossing of Phantom Divide in F(r) Gravity  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An explicit model of F(R) gravity with realizing a crossing of the phantom divide is reconstructed. In particular, it is shown that the Big Rip singularity may appear in the reconstructed model of F(R) gravity. Such a Big Rip singularity could be avoided by adding R2 term or non-singular viable F(R) theory1 to the model because phantom behavior becomes transient.

Bamba, Kazuharu; Geng, Chao-qiang; Nojiri, Shin Ichi; Odintsov, Sergei D.

2010-01-01

256

Multi-dividing Ontology Algorithm in Auc Criterion Setting (II  

Directory of Open Access Journals (Sweden)

Full Text Available As the extension of Gao et al. (2013, we present the partitioning scheme made of dyadic cubes, the approximation result is thereby obtained concern such partitioning. It is highlighted in this study that AUC criterion multi-dividing ontology algorithm with tree ontology structure and specific split rule has good statistic characteristics, and show that the algorithm under these partitioning schemes are convergent.

Li Yan

2013-01-01

257

Dividing Streamline Formation Channel Confluences by Physical Modeling  

Directory of Open Access Journals (Sweden)

Full Text Available Confluence channels are often found in open channel network system and is the most important element. The incoming flow from the branch channel to the main cause various forms and cause vortex flow. Phenomenon can cause erosion of the side wall of the channel, the bed channel scour and sedimentation in the downstream confluence channel. To control these problems needed research into the current width of the branch channel. The incoming flow from the branch channel to the main channel flow bounded by a line distributors (dividing streamline. In this paper, the wide dividing streamline observed in the laboratory using a physical model of two open channels, a square that formed an angle of 30º. Observations were made with a variety of flow coming from each channel. The results obtained in the laboratory observation that the width of dividing streamline flow is influenced by the discharge ratio between the channel branch with the main channel. While the results of a comparison with previous studies showing that the observation in the laboratory is smaller than the results of previous research.

Minarni Nur Trilita

2010-02-01

258

Experimenting Oriya Text Chunking with Divide-Conquer Strategy  

Directory of Open Access Journals (Sweden)

Full Text Available The traditional oriya text chunking approach identifies phrase structure or local word group by using only one model and phrases with the same types of features. Generally oriya language is a free word order language. Free word order languages have relatively unrestricted local word group or phrase structures that make the problem of chunking quite challenging It has been shown that the limitations of using only one model are that: the use of the same types of features is not suitable for all phrases.. In this paper, the divide-conquer approach is proposed and applied in the identification of phrases or local word group. This strategy divides the task of chunking into several sub-tasks according to sensitive features of each phrase and identifies different phrases in parallel. Then, a two-stage decreasing conflict strategy is used to synthesize each sub-task’s answer We argue that we might not need an explicit intermediate POS-tagging step for parsing when a sufficient amount of training material is available and word form information is used for low-frequency words. By applying and testing the approach on the public training and test corpus, the F score for arbitrary phrases identification using divide-conquer strategy achieves 91.3% compared to the previous best F score of 92.18%.

Rakesh Chandra Balabantaray

2010-12-01

259

Influence of heating in on-chip resistors on frequency-to-current conversion in short arrays of small Josephson junctions  

International Nuclear Information System (INIS)

Small Josephson junctions can exhibit charge quantization effects and Bloch oscillations which are very much the electromagnetic dual to the behaviour of larger junctions. As such they can exhibit constant-current steps at I=2ef when an external drive of frequency f is applied, dual to the well-known constant-voltage Shapiro steps exhibited by larger junctions. This is of interest for a possible current standard. Observation of these steps demonstrating phase lock of the Bloch oscillations with the external drive requires a high-impedance environment for the junctions, which is provided by on-chip resistors close to the junctions. Those resistors will inevitably be heated by the produced current. We experimentally determine the temperature dependence of miniature on-chip resistors on heating current and present circuit simulations incorporating this data as well as realistic values for stray capacitances and junction parameters. These simulations show that with harmonic drive there is practically no parameter window where observation of a flat current plateau is possible. However, a pulsed drive analogous to what is employed for AC voltage standards could enable direct frequency-to-current conversion with current technology. We also discuss potential problems not addressed in the simulations, in particular non-equilibrium quasi-particles in the superconductor.

2012-03-25

260

Conduction mechanisms and 1/f noise in thick-film resistors with Pb3Rh7O15 and Pb2Ru2O7  

International Nuclear Information System (INIS)

Thick-film resistors with Pb3Rh7015 and Pb2Ru207 as conductors are considered. These compounds are chemically stable during the firing process of the resistors. The variation of sheet resistivity R/sub D'Alembertian/ with volume fraction conductor follows a simple power law. This result cannot be explained by percolation theory in its simple form. The conductivity is found to be independent of frequency up to 10 GHz. In both cases a small positive Hall coefficient is observed which is interpreted as being due to mixed electron and hole conduction. Finally the 1/f noise is considered, and is found to vary approximately linearly with R/sub D'Alembertian/. A theoretical model for the 1/f noise in thick-film resistors is presented that accounts for this linear relationship. The observed deviations from linearity indicate that probably tunneling through barriers at the interfaces between the conducting grains is an important factor in determining the conduction

1981-01-01

 
 
 
 
261

Water  

...the Private Water Supplies Regulations (Northern Ireland) 1994. The Drinking Water Inspectorate:regulates drinking water quality in Northern Ireland for public and private suppliesassesses drinking water quality against...

262

The Patronage of Thirst: Exploring Institutional Fit on a Divided Cyprus  

Directory of Open Access Journals (Sweden)

Full Text Available We explore the links between Cyprus's colonial past, divided present, and current water scarcity. With reference to the concept of fit, we tackle the question of whether we can observe fit in settings where institutions for collective action work differently than we would expect. We perform a secondary analysis of interview materials on Cyprus's water conflicts, extracting arguments for and against different solutions to water scarcity. Two perspectives on fit emerge: "island fit", which supports island-wide institutions; and "patronage fit", which embodies institutions that link Cypriots to their respective patrons Turkey and Greece. The analysis reveals a preference for island-wide institutional arrangements. However, rather than resting on biophysical considerations, such preference is linked to the feeling of unity of the two communities inhabiting Cyprus. We therefore observe institutions that face a trade-off between fitting to social groupings and fitting to biophysical circumstances.

Dimitrios Zikos

2013-06-01

263

CLOBAZAM SINGLE OR DIVIDED DOSE AGAINST DIAZEPAM IN ANXIETY NEUROSIS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

One-hundred-and-fifteen patients diagnosed as anxiety neurotics randomly received in a double blind study 20 mg clobazam (Frisium) as a single nightly dose (37 patients) or 10 mg b.d. (38 patients) or diazepam 5 mg b.d. (40 patients) for six weeks, followed by two weeks on placebo. Both the single and divided doses of clobazam were therapeutically equivalent to diazepam. After drug withdrawal, all three treatment groups continued to improve. Patients on clobazam showed better motor performanc...

Channabasavanna, S. M.; Pereira, L. M. Pinto

1986-01-01

264

Tamil Nadu and the Diagonal Divide in Sex Ratios  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Between 1961 and 2001, India’s 0-6 sex ratio has steadily declined. Despite evidence to the contrary, this ratio is often characterised in terms of a diagonal divide with low 0-6 sex ratios in northern and western India and normal 0-6 sex ratios in eastern and southern India. While unexpectedly high rates of female infant mortality have been reported in Tamil Nadu, it is still regarded as lying outside the ambit of states with unusually low 0-6 sex ratios. Based on an analysis of patterns i...

Bedi, A. S.; Srinivasan, S.

2009-01-01

265

Informaticiens Sans Frontières. Helping to bridge the Digital Divide  

CERN Multimedia

SF was formed as a CERN club during the World Summit for the Information Society, in Geneva, in 2003. Today we are involved in a number of international projects aimed to helping Africa bridge the Digital Divide, as well as using computing power (BOINCs) in the research against Malaria, or creating GRIDs that could allow African universities to join us in scientific research projects such as the LHC. Our latest project, named MANGO Net, is aimed at capacity building, by creating a network of computer assembly schools across the continent, which would form hardware and software technicians, create assembly centres, and lay the foundation for a future IT industry.

Josiane Uwantege

2009-01-01

266

Crossing the phantom divide with a classical Dirac field  

CERN Document Server

In this paper we consider a spatially flat Friedmann-Robertson-Walker (FRW) cosmological model with cosmological constant, containing a stiff fluid and a classical Dirac field. The proposed cosmological scenario describes the evolution of effective dark matter and dark energy components reproducing, with the help of that effective multifluid configuration, the quintessential behavior. We find the value of the scale factor where the effective dark energy component crosses the phantom divide. The model we introduce, which can be considered as a modified $\\Lambda$CDM one, is characterized by a set of parameters which may be constrained by the astrophysical observations available up to date.

Cataldo, Mauricio

2011-01-01

267

Social partners divided over government plan to raise retirement age  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The social partners have given a divided response to the Dutch cabinet’s plans to raise the retirement age – first to 66 years in 2020 and then to 67 years in 2025. This also applies to the age at which company pension schemes will be paid out. The trade unions argue that poorly paid workers who carry out heavy tasks will be unjustly burdened by these measures. Employer representatives, on the other hand, are satisfied with the proposed cutbacks on company pension schemes.

Gru?nell, M.

2009-01-01

268

Multidimensional Divide-and-Conquer and Weighted Digital Sums  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper studies three types of functions arising separately in the analysis of algorithms that we analyze exactly using similar Mellin transform techniques. The first is the solution to a Multidimensional Divide-and-Conquer (MDC) recurrence that arises when solving problems on points in $d$-dimensional space. The second involves weighted digital sums. Write $n$ in its binary representation $n=(b_i b_{i-1}... b_1 b_0)_2$ and set $S_M(n) = \\sum_{t=0}^i t^{\\bar{M}} b_t 2^t$....

Cheung, Y. K.; Flajolet, Philippe; Golin, Mordecai; Lee, C. Y. James

2010-01-01

269

Attitude estimation by divided difference filter in quaternion space  

Science.gov (United States)

This article considers the application of Divided Difference Filter (DDF) to the orientation estimation, based on a quaternion-error continuous-discrete time model. DDF is a nonlinear estimator that in contrast to Taylor's expansion of extended Kalman Filter (EKF), exploit the polynomial approximations as a multivariable extension of Stirling's interpolation formula and require no derivatives. The DDF can be based on 1st and 2nd order Stirling's interpolation, which is named the divided difference filter-1st order (DDF1) and the divided difference filter-2nd order (DDF2). The orientation kinematics is defined in a quaternion vector space that unlike the Euler angle representation does not have any singularity problem. The presented nonlinear orientation model is an exact error model and is independent of the rigid body dynamics. The nonlinear process model includes six error-states in which only non-scalar elements of quaternion error vector are included in the error-state equations. The fourth element of quaternion error vector, which obeys unit norm constraint, is removed from system states to alleviate the estimated error covariance matrix divergence. The measurement system is a MARG sensor, which consists of a tri-axial rate gyro, a tri-axial accelerometer and a tri-axial magnetometer. The nonlinear measurement model is obtained based on the principals of magnetometer and accelerometer and the properties of the quaternion vector space. For the presented nonlinear orientation model, the performance of three filters namely DDF, EKF and Unscented Kalman Filter (UKF) is compared for different sampling frequencies in terms of the rms error, the captured area under the error norm curve, the estimated state variance and the computational cost. It is shown that under the same initial angle-error conditions, DDFs and UKF are more robust than EKF. The DDFs perform better than unscented Kalman filter (UKF) although the computational load for UKF is less. Among DDF1 and DDF2, DDF2's performance is slightly better but with more computation load. In the case of no initial angle-error conditions, the performance of the four filters is the same especially when the low noise level condition is considered.

Ahmadi, Mohammad; Khayatian, Alireza; Karimaghaee, Paknoush

2012-06-01

270

Bifurcation in asymmetric plasma divided by a magnetic filter  

International Nuclear Information System (INIS)

A magnetic filter (MF) reflecting electrons from both sides can separate a low-temperature and low-density subplasma from a high-temperature and high-density main plasma. The one-dimensional numerical simulation by the particle-in-cell code revealed that, depending on the asymmetry, the plasma divided by the MF behaves dynamically or statically [K. Ohi et al., Physics of Plasmas 8, 23 (2001)]. The transition between the two bifurcated states is discontinuous. In the dynamic state, the autonomous potential oscillation in the subplasma is synchronized with the passage of the shock wave structure generated by the modulated ion beam from the main plasma. The stationary phase of the dynamic state appears after the amplitude of the potential oscillation in the subplasma grows exponentially from the thermal noise. In the static state, the system is stable to the growth of the potential oscillation in the subplasma. (author)

2001-01-01

271

Operation of a bidirectional voltage-dividing bremsstrahlung diode  

International Nuclear Information System (INIS)

Operation of a new type of high-power electron diode, the bidirectional voltage-dividing (BVD) diode, has been demonstrated on a 1-MV, 2.5-MA, 20-ns accelerator. This diode consists of a forward- and an inverse-triaxial diode in series. The diode impedance and electron flow pattern agreed reasonably well with particle-in-cell code calculations. The radiation spectrum was measured using two different diagnostics, a differential absorption spectrometer and the time-projection Compton spectrometer. Operating at a voltage of 850--1000 kV, the BVD diode produced a bremsstrahlung spectrum similar to that produced by a standard diode operating at 350--500 kV

1990-04-01

272

Multiple sequence alignment with the Divide-and-Conquer method.  

Science.gov (United States)

An improved algorithm for the simultaneous alignment of multiple protein and nucleic acid sequences, the Divide-and-Conquer Alignment procedure (DCA), is presented. The basic method described in Tönges,et al. (1996) (Tönges, U., Perrey, S.W., Stoye, J., Dress, A.W.M., 1996. A general method for fast multiple sequence alignment. Gene, 172, GC33-GC41) is generalized to align any number of sequences to work arbitrary (e.g. affine linear) gap penalty functions. Also, the practical efficiency of the method is improved so that families of more than 10 sequences can now be aligned simultaneously within a few seconds or minutes. After a brief description of the general method, we assess the time and memory requirements of our implementation of DCA. We present several examples showing that the program is able to deal with real-world alignment problems. PMID:9669886

Stoye, J

1998-05-12

273

Re-Dividing and Coding of Urbanization Kirkuk City  

Directory of Open Access Journals (Sweden)

Full Text Available  Presented in this paper is a public service data base for Kirkuk city. The data base is based on dividing the town into a number of main districts and coding the zones and neighborhoods in each of the main distracted. This coding would help in constructing a comprehensive indexing system for the available services in the Nations zones of the city. The system may then be utilized in the plans of future expansion of the city in order to reduce discrepancies in the distribution of public services. It has been found that the block system is better and more suitable than other existing methods. It can be implemented easily by governmental establishments that are involved in such services uses geographical information system (GIS. 

Najat K. Omar

2013-05-01

274

How Visibility and Divided Attention Constrain Social Contagion  

CERN Document Server

How far and how fast does information spread in social media? Researchers have recently examined a number of factors that affect information diffusion in online social networks, including: the novelty of information, users' activity levels, who they pay attention to, and how they respond to friends' recommendations. Using URLs as markers of information, we carry out a detailed study of retweeting, the primary mechanism by which information spreads on the Twitter follower graph. Our empirical study examines how users respond to an incoming stimulus, i.e., a tweet (message) from a friend, and reveals that %retweeting behavior is constrained by a few simple principles. the "principle of least effort" combined with limited attention plays a dominant role in retweeting behavior. Specifically, we observe that users retweet information when it is most visible, such as when it near the top of their Twitter stream. Moreover, our measurements quantify how a user's limited attention is divided among incoming tweets, pro...

Hodas, Nathan Oken

2012-01-01

275

Operation of a bidirectional voltage-dividing bremsstrahlung diode  

Energy Technology Data Exchange (ETDEWEB)

Operation of a new type of high-power electron diode, the bidirectional voltage-dividing (BVD) diode, has been demonstrated on a 1-MV, 2.5-MA, 20-ns accelerator. This diode consists of a forward- and an inverse-triaxial diode in series. The diode impedance and electron flow pattern agreed reasonably well with particle-in-cell code calculations. The radiation spectrum was measured using two different diagnostics, a differential absorption spectrometer and the time-projection Compton spectrometer. Operating at a voltage of 850--1000 kV, the BVD diode produced a bremsstrahlung spectrum similar to that produced by a standard diode operating at 350--500 kV.

Harper-Slaboszewicz, V.J.; Lee, J.R.; Hedemann, M.A.; Baldwin, G.T.; Poukey, J.W.; Lorence, L.J. Jr.; Carlson, G.A.; Fowler, W.E.; Faucett, D.L.; Landron, C.O. (Sandia National Laboratories, Albuquerque, New Mexico 87185 (USA))

1990-04-01

276

Closing the divide: Can the IAEA make a difference?  

International Nuclear Information System (INIS)

Over the last two decades, the world has seen many fundamental changes in the way countries interact. It is seen today in how business is conducted, how fast travel and super-fast communications have opened up the world into almost one huge market and how news of break-through technological innovations appear almost weekly in the media. Yet the world still lives with a vast divide between rich and poor and, from many perspectives, this divide appears to be increasing. The world's development programmes have thus been increasingly scrutinized for their effectiveness and efficiency. The aim is to ensure that the planned benefits reach the end-beneficiaries in a manner that adequately addresses the socio-economic needs of the recipient society. Against this background, the IAEA's relatively small but nevertheless significant programme of technical cooperation has had to reform itself. It has gone from a largely 'technology push' focus to adopting a new 'needs driven' strategy. As the world marks 50 years of the 'Atoms for Peace' initiative, the questions must be asked whether the IAEA's Technical Cooperation Programme (TCP) really can make a difference? Is this programme correctly positioned to be able to meet these very large global challenges? Must it reform itself further to remain meaningful and relevant? What are the determinants for its success within a highly demanding environment? These are the typical questions that have largely shaped the deliberations between the IAEA Technical Cooperation Department and its Standing Advisory Group, called SAGTAC, since the group of representatives from Member States was formed in the mid- 1990s

2003-12-01

277

Eureka. Water distribution in hot water supplies; Eureka. Waterverdeling in warmwaterinstallaties  

Energy Technology Data Exchange (ETDEWEB)

Measures to be taken in case of problems with the water distribution in a water heater are discussed. Attention is paid to the possibility of applying FlowCon S1 and S2, two regulators developed by Frese armatur A/s in Denmark. These are autodynamic regulating valves: one limits the flow independent from the pressure difference over the valve, and the other regulates the flow rate and limits the differential pressure. The option to control the water distribution per radiator is also discussed on the basis of two small electric networks (a parallel connection of 4 60W resistors in combination with a 10W series resistance, and one of 4 100W resistors). 8 figs., 1 tab.

Becque, C.D. [VNI, Afdeling Technologie, Zoetermeer (Netherlands)

1995-08-01

278

BRIDGING THE KNOWLEDGE DIVIDE Educational Technology for Development  

Directory of Open Access Journals (Sweden)

Full Text Available BRIDGING THE KNOWLEDGE DIVIDEEducational Technology for DevelopmentMarshall,S., Kinuthia, W. & Wallace Taylor., Ed.D.; Information Age Publishing, Charlotte, NC, SBN: 978-1-60752-109-9, p.433, 2009Reviewed by Ozlem OZANFaculty of EducationEski?ehir Osmangazi UniversityEskisehir, TURKEYThe concept of a knowledge divide is used to describe the gap in living conditions between those who can find, manage and process information or knowledge, and those who are impaired in this, for one reason or another. In the 21st century, the emergence of the knowledge society becomes pervasive hence the information and ICT systems that support knowledge are very important.This book discusses how educational technology can be used to transform education and assist developing communities to close the knowledge divide. Its broader audience is anyone who is interested in educational technology for development. In the book you can find best practices and case studies especially from countries in Africa.The book is edited by Stewart Marshall, Wanjira Kinuthia, Wallace Taylor. Professor Stewart Marshall, PhD, is the director of the Academic Division of the University of the West Indies Open Campus (UWIOC and holds the UNESCO Chair in Educational Technologies.Dr. Wanjira Kinuthia is assistant professor of Learning Technologies at Georgia State University. She works as an instructional designer in higher education and business and industry for several years. Professor Wallace Taylor, PhD, is a founding director of The Information Society Institute (TISI, a non-profit academic, research, and policy development organization based in South Africa.The book is consisted of 433 pages (+xxxv covering 24 articles divided into four sections and provides information about flexible learning for empowerment, managing and communicating knowledge, flexible delivery in higher education and preparing teacher using flexible approaches.Topics covered in the book are as follows:Flexible Education and Community Development, Flexible Learning for Community Economic Development, Contribution of the IDE in Promoting Gender Equality and in Empowering Women in Swaziland, A Virtual Wheel of Fortune?: Enablers and Constraints of ICTs in Higher Education in South Africa, Delivering Distance Education for the Civil Service in the UK: The University of Chester’s Foundation for Government Program, Knowledge Management Strategies for Distance Education, The Effectiveness of Mobile Short Messaging Service (SMS Technologies in the Support of Selected Distance Education Students of Makerere University, Uganda, The Impact of Video Conferencing on Distance Education Courses: A University of Namibia Case Study, Open Resources for Open Learning in Developing Countries: Deciphering Trends for Policies, Quality, and Standards Considerations, Freedom, Innovation, and Equity with Open Source Software, Copyright Issues and their Impact on Flexible Education in Africa, University Education for National Development: Makerere University’s Dual Mode Experience, Considerations for Higher Education Distance Education Policy for Development: A Case of the University of Botswana,Blended Online and Face-to-Face Learning: A Pilot Project in the Faculty of Education, Eduardo Mondlane University, Evaluating the Impact of CABLE: A Cognitive Apprenticeship-Based Learning Environment, From Distance Learning to E-learning in Central and Northern Mozambique, A Framework for the Delivery of Cross-Regional Distance Education to Professionals in Developing Countries, Distance Learning—Challenges and Opportunities for Postgraduate Medical Education: A Case Study of Postgraduate Training in Family Medicine Using Distance Learning at the University of the West Indies (2001–2006, Pre-service Teacher Preparation and Effective eLearning, Distance Teacher Training in Rwanda: Comparing the Costs, Beckoning E-Learners through Exploration of Computer Technology, Educational Technology and Flexible Education in Nigeria: Meeting the Need for Effective Teacher Education, Fostering Digital Liter

Reviewed by Ozlem OZAN,

2009-10-01

279

Effect of Glass Composition on the Thermal Expansion of Relict Crystals of RuO2 in Doped Lead-Silicate Glasses (Thick Film Resistors)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The thermal expansion coefficients (TEC) of RuO2 crystallits in thick film resistor (TFR) composites, consisting of RuO2 dispersed in lead-silicate glass of various compositions, were evaluated from X-ray diffraction patterns at temperatures 298; 773; 973 and 1123 K corresponding to characteristic temperatures of resistivity and thermopower anomalies of the TFRs. It has been found that TEC of free RuO2 powder along a-axis ha...

Gulmurza Abdurakhmanov

2011-01-01

280

Universal logic gates via liquid-electronic hybrid divider.  

Science.gov (United States)

We demonstrated two-input microdroplet-based universal logic gates using a liquid-electronic hybrid divider. All 16 Boolean logic functions have been realized by manipulating the applied voltages. The novel platform consists of a microfluidic chip with integrated microdroplet detectors and external electronic components. The microdroplet detectors act as the communication media for fluidic and electronic information exchange. The presence or absence of microdroplets at the detector translates into the binary signal 1 or 0. The embedded micro-mechanical pneumatically actuated valve (PAV), fabricated using the well-developed multilayer soft lithography technique, offers biocompatibility, flexibility and accuracy for the on-chip realization of different logic functions. The microfluidic chip can be scaled up to construct large-scale microfluidic logic computation. On the other hand, the microfluidic chip with a specific logic function can be applied to droplet-based chemical reactions for on-demand bio or chemical analysis. Our experimental results have presented an autonomously driven, precision-controlled microfluidic chip for chemical reactions based on the IF logic function. PMID:23111629

Zhou, Bingpu; Wang, Limu; Li, Shunbo; Wang, Xiang; Hui, Yu Sanna; Wen, Weijia

2012-12-21

 
 
 
 
281

The Digital Divide in Romania – A Statistical Analysis  

Directory of Open Access Journals (Sweden)

Full Text Available The digital divide is a subject of major importance in the current economic circumstances in which Information and Communication Technologies (ICT are seen as a significant determinant of increasing the domestic competitiveness and contribute to better life quality. Latest international reports regarding various aspects of ICT usage in modern society reveal a decrease of overall digital disparity towards the average trends of the worldwide ITC’s sector – this relates to latest advances of mobile and computer penetration rates, both for personal use and for households/ business. In Romania, the low starting point in the development of economy and society in the ICT direction was, in some extent, compensated by the rapid annual growth of the last decade. Even with these dynamic developments, the statistical data still indicate poor positions in European Union hierarchy; in this respect, the prospects of a rapid recovery of the low performance of the Romanian ICT endowment and usage and the issue continue to be regarded as a challenge for progress in economic and societal terms. The paper presents several methods for assessing the current state of ICT related aspects in terms of Internet usage based on the latest data provided by international databases. The current position of Romanian economy is judged according to several economy using statistical methods based on variability measurements: the descriptive statistics indicators, static measures of disparities and distance metrics.

Daniela BORISOV

2012-06-01

282

Study and achievement of a digital-analog-divider  

International Nuclear Information System (INIS)

This apparatus is designed to give directly, in digital form, the value of the ratio Vt1/V2 two analog voltages. It consists essentially of an analog-digital coder operating by successive weighing; the comparison voltage is made proportional to the divider V2 in the coder. The input dynamics are such that the voltages Vi and V2 are all in the range -50 mV to -5 V. Each of the circuits has an input impedance of about 10 K?. As for the quotient, it is a binary number given in series and parallel form; it is made up of 8 bits, this giving a change of 1/16 to 16 per jump of 1/16 in the zone where the accuracy is highest (V2 ? 800 mV). The time required for a division is, at best, 15 ?sec. During the time of calculation, the voltages V_1 and V_2 should not vary by more than 1 per cent and 0.5 per cent respectively. The theory of the system and the investigation of a synoptic diagram, the study of the circuits and the actual construction are presented. (author)

1969-01-01

283

Crossing the Phantom Divide: Theoretical Implications and Observational Status  

CERN Document Server

If the dark energy equation of state parameter w(z) crosses the phantom divide line w=-1 (or equivalently if the expression d(H^2(z))/dz - 3\\Omega_m H_0^2 (1+z)^2 changes sign) at recent redshifts, then there are two possible cosmological implications: Either the dark energy consists of multiple components with at least one non-canonical phantom component or general relativity needs to be extended to a more general theory on cosmological scales. The former possibility requires the existence of a phantom component which has been shown to suffer from serious theoretical problems and instabilities. Therefore, the later possibility is the simplest realistic theoretical framework in which such a crossing can be realized. After providing a pedagogical description of various dark energy observational probes, we use a set of such probes (including the Gold SnIa sample, the first year SNLS dataset, the 3-year WMAP CMB shift parameter, the SDSS baryon acoustic oscillations peak (BAO), the X-ray gas mass fraction in clu...

Nesseris, S

2006-01-01

284

What power of two divides a weighted Catalan number?  

CERN Multimedia

Given a sequence of integers b = (b_0,b_1,b_2,...) one gives a Dyck path P of length 2n the weight wt(P) = b_{h_1} b_{h_2} ... b_{h_n}, where h_i is the height of the ith ascent of P. The corresponding weighted Catalan number is C_n^b = sum_P wt(P), where the sum is over all Dyck paths of length 2n. So, in particular, the ordinary Catalan numbers C_n correspond to b_i = 1 for all i >= 0. Let xi(n) stand for the base two exponent of n, i.e., the largest power of 2 dividing n. We give a condition on b which implies that xi(C_n^b) = xi(C_n). In the special case b_i=(2i+1)^2, this settles a conjecture of Postnikov about the number of plane Morse links. Our proof generalizes the recent combinatorial proof of Deutsch and Sagan of the classical formula for xi(C_n).

Postnikov, A; Postnikov, Alexander; Sagan, Bruce

2006-01-01

285

Dividing a supercoiled DNA molecule into two independent topological domains  

Science.gov (United States)

Both prokaryotic and eukaryotic chromosomes are organized into many independent topological domains. These topological domains may be formed through constraining each DNA end from rotating by interacting with nuclear proteins; i.e., DNA-binding proteins. However, so far, evidence to support this hypothesis is still elusive. Here we developed two biochemical methods; i.e., DNA-nicking and DNA-gyrase methods to examine whether certain sequence-specific DNA-binding proteins are capable of separating a supercoiled DNA molecule into distinct topological domains. Our approach is based on the successful construction of a series of plasmid DNA templates that contain many tandem copies of one or two DNA-binding sites in two different locations. With these approaches and atomic force microscopy, we discovered that several sequence-specific DNA-binding proteins; i.e., lac repressor, gal repressor, and ? O protein, are able to divide a supercoiled DNA molecule into two independent topological domains. These topological domains are stable under our experimental conditions. Our results can be explained by a topological barrier model in which nucleoprotein complexes confine DNA supercoils to localized regions. We propose that DNA topological barriers are certain nucleoprotein complexes that contain stable toroidal supercoils assembled from DNA-looping or tightly wrapping DNA around DNA-binding proteins. The DNA topological barrier model may be a general mechanism for certain DNA-binding proteins, such as histone or histone-like proteins, to modulate topology of chromosome DNA in vivo.

Leng, Fenfei; Chen, Bo; Dunlap, David D.

2011-01-01

286

Multidimensional Divide-and-Conquer and Weighted Digital Sums  

CERN Document Server

This paper studies three types of functions arising separately in the analysis of algorithms that we analyze exactly using similar Mellin transform techniques. The first is the solution to a Multidimensional Divide-and-Conquer (MDC) recurrence that arises when solving problems on points in $d$-dimensional space. The second involves weighted digital sums. Write $n$ in its binary representation $n=(b_i b_{i-1}... b_1 b_0)_2$ and set $S_M(n) = \\sum_{t=0}^i t^{\\bar{M}} b_t 2^t$. We analyze the average $TS_M(n) = \\frac{1}{n}\\sum_{j i_2 > ... > i_k\\geq 0$ and set $W_M(n) = \\sum_{t=1}^k t^M 2^{i_t}$. We analyze the average $TW_M(n) = \\frac{1}{n}\\sum_{j

Cheung, Y K; Golin, Mordecai; Lee, C Y James

2010-01-01

287

Cell survival assays in a slowly dividing normal tissue  

International Nuclear Information System (INIS)

In order to assess the significance of changes in clonogenic survival of type II pneumonocytes after radiation and other treatments, the present study has developed further an established lung disaggregation technique (Guichard et al. 1980). In vitro radiosensitivity of the dis-aggregated lung cells has been assessed by colony formation in vitro after irradiating cell suspensions with X-rays or with neutrons. Lung cell clonogenicity after in vivo irradiation with X-rays and neutrons has also been examined by in vitro colony formation following disaggregation after various time intervals post irradiation. The intervals were chosen to provide direct comparison with the previous in vivo studies which had demonstrated a 'slow repair' phenomenon in mouse lung (Field et al., 1976). Five Gy X-rays resulted in only approx. 4% of cells retaining colony forming ability if called upon to divide shortly after irradiation. However, 75% of these same cells were capable of colony formation if repair processes were allowed to proceed without interruption for three weeks. (UK)

1986-01-01

288

Water  

... +1 252 328 5578 Website: http://core.ecu.edu/geology/ODriscoll/ODriscoll/home.html E-Mail: odriscollm@ecu.edu Interests: surface water/groundwater interactions; stable ...Bjornlund Interests: water management; water policy; economic instruments; impact assessment; water markets; irrigation; sustainable irrigation Prof. Dr. Maria ... +1 252 328 5578 Website: http://core.ecu.edu/geology/ODriscoll/ODriscoll/home.html Interests: surface water/groundwater interactions; stable isotope hydrology; human impacts ... +33 (0)1 6908 6650; Fax: +33 (0)1 6908 8261 Interests: liquids; water; aqueous solutions; neutron scattering; X ray scattering; colloids; membranes; hydration; porous materials; fractals ...

289

Crossing cultural divides: moral conflict and the Cairo population conference.  

Science.gov (United States)

This essay considers the public conflict that arose during the drafting of the Programme of Action of the 1994 International Conference on Population and Development (ICPD) as reflecting a moral argument between interest groups holding different world views. These differences are seen as running through and across civilizations rather than being civilization-specific. The essay opens with background information on the development of the concepts of population control and population stabilization as well as the adoption of national population policies and the goals of population programs. The public conflict over the ICPD is then reiterated and is seen to be something other than the usual "West versus the rest" tension or a "religious" versus "secular" battle. Instead the divide can be broadly categorized as "orthodox" versus "progressive." The contested issues included a conflict over language relating to abortion, marriage and the family, promiscuity and adultery, and development and international migration. The conflict over human rights involved health rights versus nonmedicalized moral norms, individual rights versus family rights, and sustainable development versus integral development. The underriding conflict is seen to be a conflict between those holding orthodox versus progressive world views over who will shape the future. The tactics of this high-stakes conflict included portraying the other side as fanatics, treating the moral debate as a distraction from more important issues, charging the other side with having a hidden agenda, and isolating certain ideas from the possibility of discussion. With 92% of the Draft Programme of Action uncontested, both sides made compromises that resulted in the gist of the text remaining intact. Because the result of implementation of the Programme of Action will be cultural change, the conflict did not end with the ICPD. As the globalization of Western culture proceeds, cross-cultural moral conflicts may arise. PMID:12320389

Davis, J E

1995-01-01

290

HIV-1 latency in actively dividing human T cell lines  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Eradication of HIV-1 from an infected individual cannot be achieved by current drug regimens. Viral reservoirs established early during the infection remain unaffected by anti-retroviral therapy and are able to replenish systemic infection upon interruption of the treatment. Therapeutic targeting of viral latency will require a better understanding of the basic mechanisms underlying the establishment and long-term maintenance of HIV-1 in resting memory CD4 T cells, the most prominent reservoir of transcriptional silent provirus. However, the molecular mechanisms that permit long-term transcriptional control of proviral gene expression in these cells are still not well understood. Exploring the molecular details of viral latency will provide new insights for eventual future therapeutics that aim at viral eradication. Results We set out to develop a new in vitro HIV-1 latency model system using the doxycycline (dox-inducible HIV-rtTA variant. Stable cell clones were generated with a silent HIV-1 provirus, which can subsequently be activated by dox-addition. Surprisingly, only a minority of the cells was able to induce viral gene expression and a spreading infection, eventhough these experiments were performed with the actively dividing SupT1 T cell line. These latent proviruses are responsive to TNF? treatment and alteration of the DNA methylation status with 5-Azacytidine or genistein, but not responsive to the regular T cell activators PMA and IL2. Follow-up experiments in several T cell lines and with wild-type HIV-1 support these findings. Conclusion We describe the development of a new in vitro model for HIV-1 latency and discuss the advantages of this system. The data suggest that HIV-1 proviral latency is not restricted to resting T cells, but rather an intrinsic property of the virus.

Berkhout Ben

2008-04-01

291

Bridging the transatlantic climate divide. Final project paper  

International Nuclear Information System (INIS)

International climate change policy is presently dominated by the different visions of two major blocks, the USA and EU. It is not always realized that a part of these differences is more fundamental than one may expect in view of the historical connections between the populations of the two continents. Socio-cultural aspects like the role of government, the value of individual liberty and the consequences of population density are different in both regions and play an important role in determining what is acceptable policy-wise. Despite the apparent stalemate in formal positions, signs have been detected that indicate that the 'transatlantic divide' on this issue is (slowly) closing. One cause is that bottom-up momentum is building up in the USA, which can eventually push the federal level to initiate a more active policy. Another cause is the finding in the EU that it turns out to be difficult to reach the Kyoto-targets, which results in the development of policy instruments that could be attractive for the USA to endorse or even participate in. Such instruments could have similarities with the Kyoto Protocol. To obtain more insight in the driving forces behind such changes and why they lead to higher or lower acceptability of certain policy instruments, it makes sense to identify attitudinal indicators that signify such changes. By regularly monitoring these attitudinal indicators, e.g., concrete behavior of companies, proportional media attention, formal political statements, and relating the value of these indicators to a corresponding set of policy instruments, policy makers at both sides of the Atlantic Ocean have an extra tool at their disposal to frame the issue and identify joint solutions in a way that is acceptable to the other party. This project makes a first attempt to design such a method (dynamic analytic model). It holds promises, and it is recommended to develop this model further in order to support the effectiveness of the climate negotiations

2005-01-01

292

Bridging the transatlantic climate divide. Final project paper. Appendices  

International Nuclear Information System (INIS)

International climate change policy is presently dominated by the different visions of two major blocks, the USA and EU. It is not always realized that a part of these differences is more fundamental than one may expect in view of the historical connections between the populations of the two continents. Socio-cultural aspects like the role of government, the value of individual liberty and the consequences of population density are different in both regions and play an important role in determining what is acceptable policy-wise. Despite the apparent stalemate in formal positions, signs have been detected that indicate that the 'transatlantic divide' on this issue is (slowly) closing. One cause is that bottom-up momentum is building up in the USA, which can eventually push the federal level to initiate a more active policy. Another cause is the finding in the EU that it turns out to be difficult to reach the Kyoto-targets, which results in the development of policy instruments that could be attractive for the USA to endorse or even participate in. Such instruments could have similarities with the Kyoto Protocol. To obtain more insight in the driving forces behind such changes and why they lead to higher or lower acceptability of certain policy instruments, it makes sense to identify attitudinal indicators that signify such changes. By regularly monitoring these attitudinal indicators, e.g., concrete behavior of companies, proportional media attention, formal political statements, and relating the value of these indicators to a corresponding set of policy instruments, policy makers at both sides of the Atlantic Ocean have an extra tool at their disposal to frame the issue and identify joint solutions in a way that is acceptable to the other party. This project makes a first attempt to design such a method (dynamic analytic model). It holds promises, and it is recommended to develop this model further in order to support the effectiveness of the climate negotiations

2005-01-01

293

Studies on microcalorimetric gas analysis on the basis of ceramic PTC resistors. Untersuchungen zur Gasanalyse mit Mikrokalorimetern auf der Basis keramischer PTC-Widerstaende  

Energy Technology Data Exchange (ETDEWEB)

The temperature dependence of the reaction rate and thus the combustion performance of catalytic combustion reactions is the basis for a gas analysis of inflammable gases in air. This study developed a new type of a calorimetric gas sensor (PTC microcalorimeter) for the isothermal measurement of the combustion performance. Here, a ceramic PTC resistor forms both the heating substrate for the catalyst and the measuring unit for the released reaction heat. It is possible to determine the combustion performance almost isothermally ({Delta}T < 0.2 K) with a high resolution (< 40 ppm for H{sub 2}) by operating the PTC resistor in self-heating operation. On the basis of the characteristic signal patterns of the gases H{sub 2}, CO, ethanol, n-butane and propane a possible gas identification of an individual inflammable gas in air was demonstrated by using a sensor system of 8 parallel operating PTC microcalorimeters with graduated reference and thus operating temperatures of the PTC ceramics. In the case of mixtures of two inflammable gases in air (butane and H{sub 2}, propane and H{sub 2}, propane and butane) an almost unimpaired superposition of the combustion reactions was observed. A model for the analysis of binary mixtures of inflammable gases in air was developed from the linear superposition of the reaction rates of the individual reactions. (orig./RB) With 68 figs., 14 tabs.

Riegel, J.

1989-01-01

294

Divide and Conquer: resonance induced by competitive interactions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Since few systems exist in isolation, a key question is how a system responds to an environmental forcing. Whether we think about how the brain can encode information, a ?sh detect food in muddy waters, or an advertiser in?uence the market, this very general challenge spans di?erent disciplines and is dealt with by the adoption of di?erent strategies. Nevertheless, those strategies basically fall into one of two categories: either to increase the strength of the exte...

Vaz Martins, Teresa

2010-01-01

295

Dividers for reduction of aerodynamic drag of vehicles with open cavities  

Science.gov (United States)

A drag-reduction concept for vehicles with open cavities includes dividing a cavity into smaller adjacent cavities through installation of one or more vertical dividers. The dividers may extend the full depth of the cavity or only partial depth. In either application, the top of the dividers are typically flush with the top of the bed or cargo bay of the vehicle. The dividers may be of any material, but are strong enough for both wind loads and forces encountered during cargo loading/unloading. For partial depth dividers, a structural angle may be desired to increase strength.

Storms, Bruce L. (Inventor)

2007-01-01

296

A dividing lubricant for coating metallic coking chambers  

Energy Technology Data Exchange (ETDEWEB)

In the common separating lubricant (PS) for coating coking chambers, in order to improve the adhesion properties, heat conductivity and sedimentation stability, as well as to eliminate the ash content of the PS, oleic acid is used as the adhesion additive, carbon black and graphite or annealed petroleum coke is used as the hydrocarbon filler and carbamide is used as the binder. The relationship of the components in percent is: graphite or annealed petroleum coke, 5 to 12; carbon black, 5 to 12; carbamide, 7 to 10; oxyethylated alkylphenol, 0.3 to 0.5; oleic acid, 0.5 to 1 and water to 100 percent. It is shown as a result of testing of the separating lubricant that the graphite additive promotes the even transmission of heat to the coking raw material. The proposed PS prevents the sedimentation of the carboids in the cube loading stage and the onset of coking, eliminates local overheatings and burn through of the lower sheets.

Gimayev, R.N.; Bilyalov, R.M.; Kurochkin, A.K.; Telyashev, G.G.; Usmanov, R.M.

1982-01-01

297

Effect of dividing in sections on the dynamic stability and electric losses in superconducting helicoids  

International Nuclear Information System (INIS)

The influence of dividing in sections of superconducting helicoids on electrical losses and dynamic stability was theoretically investigated. Mathematical expressions of losses and stability limit were obtained for different models of ordinary and divided superconducting helicoid. It has been shown, that dividing of helicoid in series electrically connected sections decreased losses and increased the dynamic stability limit strongly. 5 refs.; 8 figs

1989-01-01

298

The experiment and analysis of tailoring V_L and I_P with ZnO voltage-sensitive resistor on HT-6M  

International Nuclear Information System (INIS)

The idea of improving plateau with ZnO 'varistor' (voltage sensitive resistor) is presented. The result of tailoring V_L and I_P experiment on HT-6M tokamak is introduced. An improved tens millisecond plateau was achieved (?V_L/V_L<5%, ?I_p/I_p<5%, ?N_e/N_e<10%). Obviously, it is of great importance for many diagnostic measurements and further physics experiments to have the constant distribution of temperature and density. A simplified analysis of the actual poloidal circuit of HT-6M is given. The numerical simulation and the result of experiment are compared. The operating principle of the varistor and its application on iron core transformer tokamak in plateau and rising phase are mentioned

1992-01-01

299

Effect of Glass Composition on the Thermal Expansion of Relict Crystals of RuO2 in Doped Lead-Silicate Glasses (Thick Film Resistors  

Directory of Open Access Journals (Sweden)

Full Text Available The thermal expansion coefficients (TEC of RuO2 crystallits in thick film resistor (TFR composites, consisting of RuO2 dispersed in lead-silicate glass of various compositions, were evaluated from X-ray diffraction patterns at temperatures 298; 773; 973 and 1123 K corresponding to characteristic temperatures of resistivity and thermopower anomalies of the TFRs. It has been found that TEC of free RuO2 powder along a-axis has an anomaly at T > 973 K (expansion is replaced by constriction, whereas constriction along c-axes remains for all temperatures. This anomaly disappears in doped glass of simplest composition (2SiO2.PbO but occurs in glasses of some complex compositions. Symmetry of unit cell of RuO2 is not changed in the temperature range investigated.

Gulmurza Abdurakhmanov

2011-07-01

300

Transmission electron microscopy structure and platinum-like temperature coefficient of resistance in a ruthenate-based thick film resistor with copper oxide  

Science.gov (United States)

As an alternative to thin-film platinum temperature sensor elements, thick film resistor ones are of interest for circuits which can withstand a near-engine environment. From a pyrochlore paste (DuPont 5091D), a close match is obtained (after firing) to the positive temperature coefficient of resistance (TCR) of Pt. Within the glassy matrix during 850 °C firing, needle-like RuO2 grains grow by a mechanism consistent with periodic bond chain theory. The acicular growth habit is attributed to a Cu2O additive, which is assumed to oxidize upon firing. The needles provide direct paths for metallic conduction and a characteristic positive TCR to the thick film in spite of having a low RuO2 volume fraction.

Jiang, J. C.; Crosbie, Gary M.; Tian, W.; Cameron, K. K.; Pan, X. Q.

2000-07-01

 
 
 
 
301

Capacitive divider for voltage measurement of diode load on Qiangguang-I Accelerator  

International Nuclear Information System (INIS)

A kind of self-integrating capacitive divider is introduced to measure the diode load voltage on the Qiangguang-I accelerator. The structure of the divider is given first and the static electric field of the divider is simulated by ANSYS. The calculation result shows that no significant effect is induced on the electric field between the anode board and the cathode board, when the divider is located in a small hole on the anode board. By using the square pulse voltage generator and the standard resistance divider the frequency response and the attenuation ratio of the capacitive divider are calibrated. At last the divider-measured voltage of the short-circuit load on the Qiangguang-I accelerator is given. (authors)

2010-03-01

302

A divide-conquer-recombine algorithmic paradigm for large spatiotemporal quantum molecular dynamics simulations  

International Nuclear Information System (INIS)

We introduce an extension of the divide-and-conquer (DC) algorithmic paradigm called divide-conquer-recombine (DCR) to perform large quantum molecular dynamics (QMD) simulations on massively parallel supercomputers, in which interatomic forces are computed quantum mechanically in the framework of density functional theory (DFT). In DCR, the DC phase constructs globally informed, overlapping local-domain solutions, which in the recombine phase are synthesized into a global solution encompassing large spatiotemporal scales. For the DC phase, we design a lean divide-and-conquer (LDC) DFT algorithm, which significantly reduces the prefactor of the O(N) computational cost for N electrons by applying a density-adaptive boundary condition at the peripheries of the DC domains. Our globally scalable and locally efficient solver is based on a hybrid real-reciprocal space approach that combines: (1) a highly scalable real-space multigrid to represent the global charge density; and (2) a numerically efficient plane-wave basis for local electronic wave functions and charge density within each domain. Hybrid space-band decomposition is used to implement the LDC-DFT algorithm on parallel computers. A benchmark test on an IBM Blue Gene/Q computer exhibits an isogranular parallel efficiency of 0.984 on 786?432 cores for a 50.3 × 106-atom SiC system. As a test of production runs, LDC-DFT-based QMD simulation involving 16?661 atoms is performed on the Blue Gene/Q to study on-demand production of hydrogen gas from water using LiAl alloy particles. As an example of the recombine phase, LDC-DFT electronic structures are used as a basis set to describe global photoexcitation dynamics with nonadiabatic QMD (NAQMD) and kinetic Monte Carlo (KMC) methods. The NAQMD simulations are based on the linear response time-dependent density functional theory to describe electronic excited states and a surface-hopping approach to describe transitions between the excited states. A series of techniques are employed for efficiently calculating the long-range exact exchange correction and excited-state forces. The NAQMD trajectories are analyzed to extract the rates of various excitonic processes, which are then used in KMC simulation to study the dynamics of the global exciton flow network. This has allowed the study of large-scale photoexcitation dynamics in 6400-atom amorphous molecular solid, reaching the experimental time scales

2014-05-14

303

A divide-conquer-recombine algorithmic paradigm for large spatiotemporal quantum molecular dynamics simulations  

Science.gov (United States)

We introduce an extension of the divide-and-conquer (DC) algorithmic paradigm called divide-conquer-recombine (DCR) to perform large quantum molecular dynamics (QMD) simulations on massively parallel supercomputers, in which interatomic forces are computed quantum mechanically in the framework of density functional theory (DFT). In DCR, the DC phase constructs globally informed, overlapping local-domain solutions, which in the recombine phase are synthesized into a global solution encompassing large spatiotemporal scales. For the DC phase, we design a lean divide-and-conquer (LDC) DFT algorithm, which significantly reduces the prefactor of the O(N) computational cost for N electrons by applying a density-adaptive boundary condition at the peripheries of the DC domains. Our globally scalable and locally efficient solver is based on a hybrid real-reciprocal space approach that combines: (1) a highly scalable real-space multigrid to represent the global charge density; and (2) a numerically efficient plane-wave basis for local electronic wave functions and charge density within each domain. Hybrid space-band decomposition is used to implement the LDC-DFT algorithm on parallel computers. A benchmark test on an IBM Blue Gene/Q computer exhibits an isogranular parallel efficiency of 0.984 on 786 432 cores for a 50.3 × 106-atom SiC system. As a test of production runs, LDC-DFT-based QMD simulation involving 16 661 atoms is performed on the Blue Gene/Q to study on-demand production of hydrogen gas from water using LiAl alloy particles. As an example of the recombine phase, LDC-DFT electronic structures are used as a basis set to describe global photoexcitation dynamics with nonadiabatic QMD (NAQMD) and kinetic Monte Carlo (KMC) methods. The NAQMD simulations are based on the linear response time-dependent density functional theory to describe electronic excited states and a surface-hopping approach to describe transitions between the excited states. A series of techniques are employed for efficiently calculating the long-range exact exchange correction and excited-state forces. The NAQMD trajectories are analyzed to extract the rates of various excitonic processes, which are then used in KMC simulation to study the dynamics of the global exciton flow network. This has allowed the study of large-scale photoexcitation dynamics in 6400-atom amorphous molecular solid, reaching the experimental time scales.

Shimojo, Fuyuki; Hattori, Shinnosuke; Kalia, Rajiv K.; Kunaseth, Manaschai; Mou, Weiwei; Nakano, Aiichiro; Nomura, Ken-ichi; Ohmura, Satoshi; Rajak, Pankaj; Shimamura, Kohei; Vashishta, Priya

2014-05-01

304

A divide-conquer-recombine algorithmic paradigm for large spatiotemporal quantum molecular dynamics simulations.  

Science.gov (United States)

We introduce an extension of the divide-and-conquer (DC) algorithmic paradigm called divide-conquer-recombine (DCR) to perform large quantum molecular dynamics (QMD) simulations on massively parallel supercomputers, in which interatomic forces are computed quantum mechanically in the framework of density functional theory (DFT). In DCR, the DC phase constructs globally informed, overlapping local-domain solutions, which in the recombine phase are synthesized into a global solution encompassing large spatiotemporal scales. For the DC phase, we design a lean divide-and-conquer (LDC) DFT algorithm, which significantly reduces the prefactor of the O(N) computational cost for N electrons by applying a density-adaptive boundary condition at the peripheries of the DC domains. Our globally scalable and locally efficient solver is based on a hybrid real-reciprocal space approach that combines: (1) a highly scalable real-space multigrid to represent the global charge density; and (2) a numerically efficient plane-wave basis for local electronic wave functions and charge density within each domain. Hybrid space-band decomposition is used to implement the LDC-DFT algorithm on parallel computers. A benchmark test on an IBM Blue Gene/Q computer exhibits an isogranular parallel efficiency of 0.984 on 786?432 cores for a 50.3 × 10(6)-atom SiC system. As a test of production runs, LDC-DFT-based QMD simulation involving 16?661 atoms is performed on the Blue Gene/Q to study on-demand production of hydrogen gas from water using LiAl alloy particles. As an example of the recombine phase, LDC-DFT electronic structures are used as a basis set to describe global photoexcitation dynamics with nonadiabatic QMD (NAQMD) and kinetic Monte Carlo (KMC) methods. The NAQMD simulations are based on the linear response time-dependent density functional theory to describe electronic excited states and a surface-hopping approach to describe transitions between the excited states. A series of techniques are employed for efficiently calculating the long-range exact exchange correction and excited-state forces. The NAQMD trajectories are analyzed to extract the rates of various excitonic processes, which are then used in KMC simulation to study the dynamics of the global exciton flow network. This has allowed the study of large-scale photoexcitation dynamics in 6400-atom amorphous molecular solid, reaching the experimental time scales. PMID:24832337

Shimojo, Fuyuki; Hattori, Shinnosuke; Kalia, Rajiv K; Kunaseth, Manaschai; Mou, Weiwei; Nakano, Aiichiro; Nomura, Ken-Ichi; Ohmura, Satoshi; Rajak, Pankaj; Shimamura, Kohei; Vashishta, Priya

2014-05-14

305

Comparability of the black-white divide in the American speech community and the coloured-white divide in the Afrikaans speech community  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This article attempts to place the discussion on the relationship between African American and European American vernacular Englishes within a broader context involving another speech community split along ethnic lines, namely South Africa’s Afrikaans speakers. It specifically attempts to compare observations on the coloured-white linguistic divide within South Africa’s Afrikaans speech community with those made on the black-white linguistic divide in the United States, wit...

Stell, Gerald

2012-01-01

306

Water  

Feb 6, 2014 ... Can influence the provision of other service. ... probabili-es for each site. \\DeterminaVon of human uVlisaVon factor. Classified ... Meat: ca le,sheep,goats,\\horse ... Water consumption associated with oil production driven by.

307

Water  

Science.gov (United States)

You might not give much thought to water or how it gets to you. You just turn on the faucet and there it is. Do you ever wonder how it flows from your faucet? And have you ever stopped to think about whether or not it is clean? For most people ...

308

UVA Virtual Lab: Capacitor Water Tank Analogy  

Science.gov (United States)

These pages provide a water model of an electrical circuit. In this case, the gerbil running in its wheel and the bucket pump are the equivalent of a battery. The water represents the flowing electrons. The membrane in the middle is the circuitâs capacitor. The spinning waterwheel represents the resistor which powers the light bulb. This model is part of the UVA Virtual Lab collection. This project is supported by grants from the National Science Foundation, the University of Virginia, IBM, and Discreet Corporation.

Bean, John

2010-12-23

309

Digital divide and digital opportunity: Comparison, analysis and strategies for sustainable development in developing nations  

International Nuclear Information System (INIS)

The world is witnessing a new digital economic order which may be quantified by the diffusion of information technology and globalization process. The current information technology gap (digital divide) between developed countries and developing countries is huge. Improvements in information technology (measured by the digital opportunity index) usually open up an opportunity for national/regional growth and development. There is a need for scientific investigation on the digital divide, digital opportunity index and their consequences. This paper presents a critical analysis of existing digital divide and its trends, it also investigates the relationship between the digital divide and the digital opportunity index. A mathematical model based on analysis of the growing digital divide is presented as a possible tool for combating and eradicate the digital divide gap which is only possible if developing and poor nations take advantage of the digital opportunities that can transform them into global competitive partners in digital knowledge economy. (author)

2007-01-01

310

The effect of divided attention on false memory depends on how memory is tested.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In three experiments, we investigated the effects of divided attention on false memory, using the Deese/Roediger-McDermott (DRM) paradigm. In Experiments 1 and 2, participants studied six DRM lists with full attention and six in one of two divided-attention conditions (random number generation or digit monitoring). Both divided-attention conditions increased false recall of related words (Experiment 1) but reduced false recognition (Experiment 2). These results were confirmed in Experiment 3,...

2007-01-01

311

Unobtrusive Monitoring of Divided Attention in a Cognitive Health Coaching Intervention for the Elderly  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Assessment of cognitive functionality is an important aspect of care for elders. Unfortunately, few tools exist to measure divided attention, the ability to allocate attention to different aspects of tasks. An accurate determination of divided attention would allow inference of generalized cognitive decline, as well as providing a quantifiable indicator of an important component of driving skill. We propose a new method for determining relative divided attention ability through unobtrusive mo...

Mckanna, James A.; Pavel, Misha; Jimison, Holly

2010-01-01

312

Divided Plato  

International Nuclear Information System (INIS)

His experience as nuclear physicist, univerity professor, and research promoter recommend the author as a partner in the discussion on progress. He shows what kind of man a scientist is, which motivations he has, what he can do. He explains how it is possible even today to find simple ways to the unknown, how the new, the unforeseeable comes into being. And he gives stimuli to and examples of the work of scientists, his responsibility and his contribution to the application of knowledge, - for instance in the field of nuclear energy - and of the contributions of science to problems of economy and politics. (orig.)

1981-01-01

313

76 FR 55643 - Helena National Forest; Montana; Divide Travel Plan EIS  

Science.gov (United States)

The Helena National Forest is preparing an Environmental Impact Statement (EIS) to analyze the effects of proposed changes to the existing motorized public access routes and prohibitions within the Divide travel planning area for wheeled and over-snow motorized vehicles. Consistent with Forest Service travel planning regulations, the designated wheeled motorized routes within the Divide Travel......

2011-09-08

314

A digital divider with extension bits for position-sensitive detectors  

International Nuclear Information System (INIS)

Digitizing errors produced in a digital divider for position-sensitive detectors have been reduced by adding extension bits to data bits. A relation between the extension bits and the data bits to obtain perfect position uniformity is also given. A digital divider employing 10 bit ADCs and 6 bit extension circuits has been constructed. (orig.)

1988-01-01

315

Development of a new lower hybrid antenna module using a poloidal power divider  

Energy Technology Data Exchange (ETDEWEB)

A realistic antenna module using a poloidal divider for lower hybrid current drive (LHCD) experiment, is modelled and fabricated. In this antenna module test II, three types of poloidal dividers, which split the power in 3, are tested. (author). 15 refs.

Maebara, S.; Imai, T.; Seki, M.; Suganuma, K. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Goniche, M.; Bibet, Ph.; Berio, S.; Brossaud, J.; Rey, G.; Tonon, G. [Association Euratom-CEA, Centre d`Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee

1997-03-01

316

Healing the Physical/Spiritual Divide through a Holistic and Hermeneutic Approach to Education  

Science.gov (United States)

In this special edition of the journal, attention is being given to the two dimensions of spirituality and physicality. In this particular paper I argue that there is an unhelpful divide that is often assumed to exist between these two dimensions and that this divide can be transcended or "healed" through a holistic and hermeneutic approach to…

Webster, R. Scott

2013-01-01

317

A 5-GHz programmable frequency divider in 0.18-?m CMOS technology  

International Nuclear Information System (INIS)

A 5-GHz CMOS programmable frequency divider whose modulus can be varied from 2403 to 2480 for 2.4-GHz ZigBee applications is presented. The divider based on a dual-modulus prescaler (DMP) and pulse-swallow counter is designed to reduce power consumption and chip area. Implemented in the 0.18-?m mixed-signal CMOS process, the divider operates over a wide range of 1-7.4 GHz with an input signal of 7.5 dBm; the programmable divider output phase noise is -125.3 dBc/Hz at an offset of 100 kHz. The core circuit without test buffer consumes 4.3 mA current from a 1.8 V power supply and occupies a chip area of approximately 0.015 mm2. The experimental results indicate that the programmable divider works well for its application in frequency synthesizers. (semiconductor integrated circuits)

2010-05-01

318

Fracture resistance evaluation of RuO2-based thick film resistor material by in situ crack extension observation in a scanning electron microscope  

International Nuclear Information System (INIS)

Parameters for the fracture mechanics of thick film materials are scarce in the literature. One reason is that for many such materials it is very difficult to produce a bulk specimen as required for most standard tests. This paper describes an alternative method for measuring the fracture resistance of a ruthenium dioxide (RuO2)-based thick film resistor material for electronic applications. The method is based on an in situ investigation of crack propagation in the loaded material. The investigated material is printed as a thick film on a substrate of low-temperature-co-fired-ceramic. An initial crack in the film is introduced with a Vickers indenter. The crack is subsequently loaded with a four-point bending equipment in a scanning electron microscope, which allows for in situ crack length measurement. The crack growth measurements reveal that once a certain crack length is achieved the load required to extend the crack becomes independent of the crack length. Beyond this length, the crack propagates in the so-called steady-state region, which is used in the present method to estimate the fracture resistance of the film. Both tensile stresses resulting from bending and tensile residual stresses are taken into account. Although a brittle substrate was used, the crack did not penetrate into the substrate. The measured fracture resistance of 0.69 ± 0.14 MPa?m is found to be realistic for the investigated thick film material with high silicate glass content

2008-10-01

319

Host Factor SAMHD1 Restricts DNA Viruses in Non-Dividing Myeloid Cells  

Digital Repository Infrastructure Vision for European Research (DRIVER)

SAMHD1 is a newly identified anti-HIV host factor that has a dNTP triphosphohydrolase activity and depletes intracellular dNTP pools in non-dividing myeloid cells. Since DNA viruses utilize cellular dNTPs, we investigated whether SAMHD1 limits the replication of DNA viruses in non-dividing myeloid target cells. Indeed, two double stranded DNA viruses, vaccinia and herpes simplex virus type 1, are subject to SAMHD1 restriction in non-dividing target cells in a dNTP dependent manner. Using a th...

Hollenbaugh, Joseph A.; Gee, Peter; Baker, Jonathon; Daly, Michele B.; Amie, Sarah M.; Tate, Jessica; Kasai, Natsumi; Kanemura, Yuka; Kim, Dong-hyun; Ward, Brian M.; Koyanagi, Yoshio; Kim, Baek

2013-01-01

320

Miniaturized and Harmonic-Suppressed RF Wilkinson Power Divider with Ib-Cmrc  

Science.gov (United States)

In this paper, the technique served by a microstrip electromagnetic band gap cell entitled IBCMRC is employed to suppress the high-order harmonics and reduce the length by over 30% for a quarter-wave conventional transmission line. The successful application of IB-CMRC cell in a 2 GHz Wilkinson power divider shows that the second and third harmonics are successfully suppressed without downgrading the performance at the operating frequency. The whole size of the proposed IBCMRC-based divider has been reduced by 42% compared to the conventional divider. In miniaturization and harmonic rejection of microwave circuits, the proposed IBCMRC technique holds great promise.

Zhang, Fei

 
 
 
 
321

A case against a divide and conquer approach to the nonsymmetric eigenvalue problem  

Energy Technology Data Exchange (ETDEWEB)

Divide and conquer techniques based on rank-one updating have proven fast, accurate, and efficient in parallel for the real symmetric tridiagonal and unitary eigenvalue problems and for the bidiagonal singular value problem. Although the divide and conquer mechanism can also be adapted to the real nonsymmetric eigenproblem in a straightforward way, most of the desirable characteristics of the other algorithms are lost. In this paper, we examine the problems of accuracy and efficiency that can stand in the way of a nonsymmetric divide and conquer eigensolver based on low-rank updating. 31 refs., 2 figs.

Jessup, E.R.

1991-12-01

322

An InGaAs/InP 40 GHz CML static frequency divider  

Science.gov (United States)

Static frequency dividers are widely used as a circuit performance benchmark or figure-of-merit indicator to gauge a particular device technology's ability to implement high speed digital and integrated high performance mixed-signal circuits. We report a 2 : 1 static frequency divider in InGaAs/InP heterojunction bipolar transistor technology. This is the first InP based digital integrated circuit ever reported on the mainland of China. The divider is implemented in differential current mode logic (CML) with 30 transistors. The circuit operated at a peak clock frequency of 40 GHz and dissipated 650 mW from a single -5 V supply.

Yongbo, Su; Zhi, Jin; Wei, Cheng; Ji, Ge; Xiantai, Wang; Gaopeng, Chen; Xinyu, Liu; Anhuai, Xu; Ming, Qi

2011-03-01

323

Variable-geometry turbocharger with asymmetric divided volute for engine exhaust gas pulse optimization  

Science.gov (United States)

A turbine assembly for a variable-geometry turbocharger includes a turbine housing defining a divided volute having first and second scrolls, wherein the first scroll has a substantially smaller volume than the second scroll. The first scroll feeds exhaust gas to a first portion of a turbine wheel upstream of the throat of the wheel, while the second scroll feeds gas to a second portion of the wheel at least part of which is downstream of the throat. Flow from the second scroll is regulated by a sliding piston. The first scroll can be optimized for low-flow conditions such that the turbocharger can operate effectively like a small fixed-geometry turbocharger when the piston is closed. The turbine housing defines an inlet that is divided by a dividing wall into two portions respectively feeding gas to the two scrolls, a leading edge of the dividing wall being downstream of the inlet mouth.

Serres, Nicolas (Epinal, FR)

2010-11-09

324

Optimum Partition Parameter of Divide-and-Conquer Algorithm for Solving Closest-Pair Problem  

CERN Multimedia

Divide and Conquer is a well known algorithmic procedure for solving many kinds of problem. In this procedure, the problem is partitioned into two parts until the problem is trivially solvable. Finding the distance of the closest pair is an interesting topic in computer science. With divide and conquer algorithm we can solve closest pair problem. Here also the problem is partitioned into two parts until the problem is trivially solvable. But it is theoretically and practically observed that sometimes partitioning the problem space into more than two parts can give better performances. In this paper, a new proposal is given that dividing the problem space into (n) number of parts can give better result while divide and conquer algorithm is used for solving the closest pair of point's problem.

Karim, Mohammad Zaidul; 10.5121/ijcsit.2011.3519

2011-01-01

325

OPTIMUM PARTITION PARAMETER OF DIVIDE-AND-CONQUER ALGORITHM FOR SOLVING CLOSEST-PAIR PROBLEM  

Directory of Open Access Journals (Sweden)

Full Text Available Divide and Conquer is a well known algorithmic procedure for solving many kinds of problem. In thisprocedure, the problem is partitioned into two parts until the problem is trivially solvable. Finding thedistance of the closest pair is an interesting topic in computer science. With divide and conqueralgorithm we can solve closest pair problem. Here also the problem is partitioned into two parts until theproblem is trivially solvable. But it is theoretically and practically observed that sometimes partitioningthe problem space into more than two parts can give better performances. In this paper, a new proposalis given that dividing the problem space into (n number of parts can give better result while divide andconquer algorithm is used for solving the closest pair of point’s problem.

Mohammad Zaidul Karim

2011-11-01

326

Review: Funston, John (ed.) (2009), Divided Over Thaksin: Thailand’s Coup and Problematic Transition  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Review of the edited volume: Funston, John (ed.) (2009), Divided Over Thaksin: Thailand’s Coup and Problematic Transition, Chiangmai: Silkworm Books, Singapore: ISEAS. ISBN 978-981-230-961-7, 203 pages.

Paul Chambers

2010-01-01

327

Review: Funston, John (ed. (2009, Divided Over Thaksin: Thailand’s Coup and Problematic Transition  

Directory of Open Access Journals (Sweden)

Full Text Available Review of the edited volume: Funston, John (ed. (2009, Divided Over Thaksin: Thailand’s Coup and Problematic Transition, Chiangmai: Silkworm Books, Singapore: ISEAS. ISBN 978-981-230-961-7, 203 pages.

Paul Chambers

2010-04-01

328

Crossing the phantom divide in extended Dvali-Gabadadze-Porrati gravity  

Science.gov (United States)

We propose a phantom crossing Dvali-Gabadadze-Porrati (DGP) model. In our model, the effective equation of state of the DGP gravity crosses the phantom divide line. We demonstrate crossing of the phantom divide does not occur within the framework of the original DGP model or the DGP model developed by Dvali and Turner. By extending their model, we construct a model that realizes crossing of the phantom divide. We find that the smaller the value of the new introduced parameter ? is, the older epoch crossing of the phantom divide occurs in. Our model can account for late-time acceleration of the universe without dark energy. We investigate and show the property of Phantom crossing DGP model.

Hirano, Koichi; Komiya, Zen

2010-11-01

329

The Queen's University of Belfast: The Liberal University in a Divided Society.  

Science.gov (United States)

The history, institutional and student characteristics, social and political context, faculty, and administrative problems of Queen's University of Belfast are discussed. The university is a liberal arts institution functioning in the deeply divided society of Northern Ireland. (MSE)

Taylor, Rupert

1988-01-01

330

The effect of divided attention on false memory depends on how memory is tested.  

Science.gov (United States)

In three experiments, we investigated the effects of divided attention on false memory, using the Deese/Roediger-McDermott (DRM) paradigm. In Experiments 1 and 2, participants studied six DRM lists with full attention and six in one of two divided-attention conditions (random number generation or digit monitoring). Both divided-attention conditions increased false recall of related words (Experiment 1) but reduced false recognition (Experiment 2). These results were confirmed in Experiment 3, in which the type of secondary task was manipulated within groups. We argue that the increase in false recall with divided attention reflects a change in participants' response criterion, whereas the decrease in false recognition occurs because the secondary tasks prevent participants from generating associates of the words presented at study. PMID:17848024

Dewhurst, Stephen A; Barry, Christopher; Swannell, Ellen R; Holmes, Selna J; Bathurst, Gemma L

2007-06-01

331

Book review: Yakinthou, C. 2009, Political Settlements in Divided Societies: Consociationalism and Cyprus  

Digital Repository Infrastructure Vision for European Research (DRIVER)

‘Political Settlements in Divided Societies’, one of the latest contributions to the literature on Cyprus, attempts to analyse the failure of the Annan Plan through the prism of consociational approaches to negotiated settlements.

Simopoulos, Michalis; Yakinthou, Christalla

2011-01-01

332

Turning immunological memory into amnesia by depletion of dividing T cells  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Immunological memory, defined as more efficient immune responses on antigen reexposure, can last for decades. The current paradigm is that memory is maintained by antigen-experienced “memory T cells” that can be long-lived quiescent or dividing. The contribution of T cell division to memory maintenance is poorly known and has important clinical implications. In this study, we directly addressed the role of dividing T cells in immunological memory maintenance by evaluating the consequences...

Bellier, Bertrand; Thomas-vaslin, Ve?ronique; Saron, Marie-franc?oise; Klatzmann, David

2003-01-01

333

Optimum Partition Parameter of Divide-and-Conquer Algorithm for Solving Closest-Pair Problem  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Divide and Conquer is a well known algorithmic procedure for solving many kinds of problem. In this procedure, the problem is partitioned into two parts until the problem is trivially solvable. Finding the distance of the closest pair is an interesting topic in computer science. With divide and conquer algorithm we can solve closest pair problem. Here also the problem is partitioned into two parts until the problem is trivially solvable. But it is theoretically and practical...

Karim, Mohammad Zaidul; Akter, Nargis

2011-01-01

334

Closing the digital divide: Southeast Asia's path towards a knowledge society  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The production, dissemination and utilisation of knowledge are essential for development and the introduction of information and communication technology (ICT) is a precondition for developing a knowledge society. Countries, regions and populations are, however, divided, in terms of access to ICT. Socio-economic indicators on Korea, Malaysia, Singapore, the Netherlands and Germany are used to show that the existing global digital divide and the knowledge gap are widening between developing co...

Evers, Hans-dieter; Gerke, Solvay

2005-01-01

335

The divide-expand-consolidate MP2 scheme goes massively parallel  

Digital Repository Infrastructure Vision for European Research (DRIVER)

For large molecular systems conventional implementations of second order MOller-Plesset (MP2) theory encounter a scaling wall, both memory- and time-wise. We describe how this scaling wall can be removed. We present a massively parallel algorithm for calculating MP2 energies and densities using the divide-expand-consolidate scheme where a calculation on a large system is divided into many small fragment calculations employing local orbital spaces. The resulting algorithm is linear-scaling wit...

2013-01-01

336

Designing elections in conflict-prone divided societies: the case of South Sudan  

Digital Repository Infrastructure Vision for European Research (DRIVER)

"Elections can contribute to peacebuilding by ensuring the representation of formerly excluded groups in parliament. When hurried and poorly designed, however, elections can also threaten the precarious peace in divided countries. This study focuses on the three main features of electoral design that crucially influence the success or failure of elections in conflict-prone divided societies: timing and sequencing, electoral administration, and electoral systems. It goes beyond purely scho...

Dreef, Sofie; Wagner, Wolfgang; Hessische Stiftung Friedens- und Konfliktforschung

2013-01-01

337

Crossing the phantom divide line in a Dvali–Gabadadze–Porrati-inspired F(R,?) gravity  

International Nuclear Information System (INIS)

We study possible crossing of the phantom divide line in a Dvali–Gabadadze–Porrati-inspired F(R,?) braneworld scenario where the scalar field and curvature quintessence are treated in a unified framework. With a specific form of F(R,?) and by adopting a suitable ansatz, we show that there are appropriate regions of the parameter space which account for late-time acceleration and admit crossing of the phantom divide line

2008-10-01

338

Combined method for simultaneously dewatering and reconstituting finely divided carbonaceous material  

Energy Technology Data Exchange (ETDEWEB)

A finely-divided carbonaceous material is dewatered and reconstituted in a combined process by adding a binding agent directly into slurry of finely divided material and dewatering the material to form a cake or consolidated piece which can be hardened by drying at ambient or elevated temperatures. Alternatively, the binder often in the form of a crusting agent is sprayed onto the surface of a moist cake prior to curing.

Wen, Wu-Wey (Murrysville, PA); Deurbrouck, Albert W. (Pittsburgh, PA)

1990-01-01

339

Implicit Divided Differences, Little Schr\\"oder Numbers, and Catalan Numbers  

CERN Document Server

Under general conditions, the equation $g(x,y) = 0$ implicitly defines $y$ locally as a function of $x$. In this short note we study the combinatorial structure underlying a recently discovered formula for the divided differences of $y$ expressed in terms of bivariate divided differences of $g$, by analyzing the number of terms $a_n$ in this formula. The main result describes six equivalent characterizations of the sequence $\\{a_n\\}$.

Muntingh, Georg

2012-01-01

340

Communication: Transition State Theory for dissipative systems without a dividing surface  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Transition state theory is a central cornerstone in reaction dynamics. Its key step is the identification of a dividing surface that is crossed only once by all reactive trajectories. This assumption is often badly violated, especially when the reactive system is coupled to an environment. The calculations made in this way then overestimate the reaction rate and the results depend critically on the choice of the dividing surface. In this Communication, we study the phase space of a stochastic...

2012-01-01

 
 
 
 
341

Statistical and numerical methods to improve the transient divided bar method  

DEFF Research Database (Denmark)

The divided bar method is a commonly used method to measure thermal conductivity of rock samples in laboratory. We present improvements to this method that allows for simultaneous measurements of both thermal conductivity and thermal diffusivity. The divided bar setup is run in a transient mode and the temperature distribution in the stack is simulated by Finite Element Modeling (FEM). A Markov Chain Monte Carlo Metropolis Hastings (MCMCMH) algorithm is used to estimate the thermal parameters of the sample.

Bording, Thue Sylvester; Balling, N.

342

110-KV optical fiber voltage transformer using a porcelain capacitor divider  

Science.gov (United States)

In this paper, a new type of optical fiber voltage transformer is introduced, which utilizes new porcelain capacitor divider. The optical; fiber voltage sensor is based on the BGO crystal Pockels effect modulated horizontally, sealed in a glass box with low expansion rate. Both the divider and the sensor are sealed in the compound silicon rubber insulator filled with SF6 gas. It has many advantages such as small volume, light weight, low price and high precision.

Ye, Miaoyuan; Ou, Chaolong; Cui, Yin; Zhou, Jianying; Li, Kaicheng; Chen, Zhiping; Xu, Yan; Luo, Sunan

1998-08-01

343

Modulation of early cortical processing during divided attention to non-contiguous locations.  

Science.gov (United States)

We often face the challenge of simultaneously attending to multiple non-contiguous regions of space. There is ongoing debate as to how spatial attention is divided under these situations. Whereas, for several years, the predominant view was that humans could divide the attentional spotlight, several recent studies argue in favor of a unitary spotlight that rhythmically samples relevant locations. Here, this issue was addressed by the use of high-density electrophysiology in concert with the multifocal m-sequence technique to examine visual evoked responses to multiple simultaneous streams of stimulation. Concurrently, we assayed the topographic distribution of alpha-band oscillatory mechanisms, a measure of attentional suppression. Participants performed a difficult detection task that required simultaneous attention to two stimuli in contiguous (undivided) or non-contiguous parts of space. In the undivided condition, the classic pattern of attentional modulation was observed, with increased amplitude of the early visual evoked response and increased alpha amplitude ipsilateral to the attended hemifield. For the divided condition, early visual responses to attended stimuli were also enhanced, and the observed multifocal topographic distribution of alpha suppression was in line with the divided attention hypothesis. These results support the existence of divided attentional spotlights, providing evidence that the corresponding modulation occurs during initial sensory processing time-frames in hierarchically early visual regions, and that suppressive mechanisms of visual attention selectively target distracter locations during divided spatial attention. PMID:24606564

Frey, Hans-Peter; Schmid, Anita M; Murphy, Jeremy W; Molholm, Sophie; Lalor, Edmund C; Foxe, John J

2014-05-01

344

100kW dummy load using water for a klystron modulator  

International Nuclear Information System (INIS)

A dummy load capable of handling the peak voltage of 37 kV and the average power of 100 kW using water as a resistor has been designed and constructed to perform the high-power tests of an X-band klystron modulator. Two coaxial electrodes are used to make the dummy load in a compact size. The load impedance is regulated in the range of 5 ? 12 ? stably. (author)

1992-01-01

345

A 5-GHz programmable frequency divider in 0.18-{mu}m CMOS technology  

Energy Technology Data Exchange (ETDEWEB)

A 5-GHz CMOS programmable frequency divider whose modulus can be varied from 2403 to 2480 for 2.4-GHz ZigBee applications is presented. The divider based on a dual-modulus prescaler (DMP) and pulse-swallow counter is designed to reduce power consumption and chip area. Implemented in the 0.18-{mu}m mixed-signal CMOS process, the divider operates over a wide range of 1-7.4 GHz with an input signal of 7.5 dBm; the programmable divider output phase noise is -125.3 dBc/Hz at an offset of 100 kHz. The core circuit without test buffer consumes 4.3 mA current from a 1.8 V power supply and occupies a chip area of approximately 0.015 mm{sup 2}. The experimental results indicate that the programmable divider works well for its application in frequency synthesizers. (semiconductor integrated circuits)

Shu Haiyong; Li Zhiqun, E-mail: zhiqunli@seu.edu.c [Institute of RF- and OE-ICs, Southeast University, Nanjing 210096 (China)

2010-05-15

346

Improved voltage dividers and calibration procedures for HV high-power tests  

Energy Technology Data Exchange (ETDEWEB)

Voltage dividers in HV laboratories are used for DC, AC, switching/lightning impulse and chopped impulse applications. Calibration procedures are prescribed by the currently revised IEC 60. Different scale factors for different applications are allowed. Voltage dividers are normally situated in well-defined arrangements together with a voltage source and a test object in a screened test bay with good earthing conditions. The situation in high power (HP) laboratories is quite different. Test objects are outdoor-type or GIS switching equipment with two or sometimes six terminals. So more than one voltage divider has to be installed in the vicinity of the test object. No interference during the high current period is allowed, which is why ground loops caused by double earthing must be avoided. Switchgear testing covers a wide range of frequencies from DC, AC, different TRV frequencies and initial conditions during closing, opening and multiple restrikes. DC coupled wide-band dividers are necessary, derived from commercial types, with improvements to avoid interference in the transmission system to the control room. Calibrations have to be made with relatively high voltages to cover a complete measuring system, including optical links and digital equipment as well. Until now there has been no IEC recommendation for this field of high power test measurements. Discussions on this matter may be of mutual interest to both HV and HP laboratories. Improvements of dividers and calibration procedures are described. (orig.)

Damstra, G.C.; Matyas, Z. [KEMA (Netherlands)

2000-07-01

347

Measuring Low Concentrations of Liquid Water in Soil  

Science.gov (United States)

An apparatus has been developed for measuring the low concentrations of liquid water and ice in relatively dry soil samples. Designed as a prototype of instruments for measuring the liquidwater and ice contents of Lunar and Martian soils, the apparatus could also be applied similarly to terrestrial desert soils and sands. The apparatus is a special-purpose impedance spectrometer: Its design is based on the fact that the electrical behavior of a typical soil sample is well approximated by a network of resistors and capacitors in which resistances decrease and capacitances increase (and, hence, the magnitude of impedance decreases) with increasing water content.

Buehler, Martin

2009-01-01

348

Large-scale atomistic simulations of nanostructured materials based on divide-and-conquer density functional theory  

Directory of Open Access Journals (Sweden)

Full Text Available A linear-scaling algorithm based on a divide-and-conquer (DC scheme is designed to perform large-scale molecular-dynamics simulations, in which interatomic forces are computed quantum mechanically in the framework of the density functional theory (DFT. This scheme is applied to the thermite reaction at an Al/Fe2O3 interface. It is found that mass diffusion and reaction rate at the interface are enhanced by a concerted metal-oxygen flip mechanism. Preliminary simulations are carried out for an aluminum particle in water based on the conventional DFT, as a target system for large-scale DC-DFT simulations. A pair of Lewis acid and base sites on the aluminum surface preferentially catalyzes hydrogen production in a low activation-barrier mechanism found in the simulations

Vashishta P.

2011-05-01

349

The pupil response is sensitive to divided attention during speech processing.  

Science.gov (United States)

Dividing attention over two streams of speech strongly decreases performance compared to focusing on only one. How divided attention affects cognitive processing load as indexed with pupillometry during speech recognition has so far not been investigated. In 12 young adults the pupil response was recorded while they focused on either one or both of two sentences that were presented dichotically and masked by fluctuating noise across a range of signal-to-noise ratios. In line with previous studies, the performance decreases when processing two target sentences instead of one. Additionally, dividing attention to process two sentences caused larger pupil dilation and later peak pupil latency than processing only one. This suggests an effect of attention on cognitive processing load (pupil dilation) during speech processing in noise. PMID:24709275

Koelewijn, Thomas; Shinn-Cunningham, Barbara G; Zekveld, Adriana A; Kramer, Sophia E

2014-06-01

350

The effect of divided attention on emotion-induced memory narrowing.  

Science.gov (United States)

Individuals are more likely to remember emotional than neutral information, but this benefit does not always extend to the surrounding background information. This memory narrowing is theorised to be linked to the availability of attentional resources at encoding. In contrast to the predictions of this theoretical account, altering participants' attentional resources at encoding by dividing attention did not affect emotion-induced memory narrowing. Attention was divided using three separate manipulations: a digit ordering task (Experiment 1), an arithmetic task (Experiment 2) and an auditory discrimination task (Experiment 3). Across all three experiments, divided attention decreased memory across the board but did not affect the degree of memory narrowing. These findings suggest that theories to explain memory narrowing must be expanded to include other potential mechanisms beyond the limitations of attentional resources. PMID:24295041

Mickley Steinmetz, Katherine R; Waring, Jill D; Kensinger, Elizabeth A

2014-08-01

351

The high voltage divider - a tool for comparison of measurement equipment in diagnostic radiology  

International Nuclear Information System (INIS)

The high voltage divider (HVD) is designed for control and analysis of the characteristics of the X-ray generator. The low voltage analogous signals produced by the divider are proportional to the high voltage (kVp) applied to the x-ray tube by a ratio 1:1000 or 1:10000 and can be measured with external test devices like storage oscilloscope (or digital multimeter). The exposure duration and the wave form may be visualized, too. Apart of this invasive way the high voltage also may be measured non-invasively by means of appropriate devices as well as indirectly through calculations. Since the invasive method of measurement with the high voltage divider is distinguished by a high accuracy, it may be utilized as an effective tool for calibration of different devices and for comparison of the measurement methods. (authors)

2004-10-14

352

Process for the manufacture of a finely divided fuel. Verfahren zur Herstellung eines feinteiligen Brennstoffes  

Energy Technology Data Exchange (ETDEWEB)

The invention concerns a process for producing a finely divided fuel from domestic refuse, industrial waste similar to domestic refuse and/or organic waste from agriculture and forestry, in which the refuse containing a part which is not combustible, after rough cutting up is subjected to magnetic separation to remove iron components and is then finely divided and dried. After the magnetic separation there is intermediate sieving, in which particles of a maximum size of 50 mm pass through the sieve. One then carries out drying to a residual humidity of a maximum of 15% by weight and further reduction in size. After this, the dried refuse reduced in size is subjected to product sieving, where the finely divided fuel is obtained with particles of a maximum size of 10 mm passing through the sieve.

Liss, U.; Skaletz, H.J.; Vollmer, H.

1987-10-22

353

Gradations in digital inclusion: children, young people and the digital divide  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Little academic and policy attention has addressed the `digital divide' among children and young people. This article analyses findings from a national survey of UK 9—19-year-olds that reveal inequalities by age, gender and socioeconomic status in relation to their quality of access to and use of the internet. Since both the extent of use and the reasons for low- and non-use of the internet vary by age, a different explanation for the digital divide is required for children compared with ad...

Livingstone, Sonia; Helsper, Ellen

2007-01-01

354

Ultralow phase noise microwave generation with an Er:fiber-based optical frequency divider  

CERN Document Server

We present an optical frequency divider based on a 200 MHz repetition rate Er:fiber mode-locked laser that, when locked to a stable optical frequency reference, generates microwave signals with absolute phase noise that is equal to or better than cryogenic microwave oscillators. At 1 Hz offset from a 10 GHz carrier, the phase noise is below -100 dBc/Hz, limited by the optical reference. For offset frequencies > 10 kHz, the phase noise is shot noise limited at -145 dBc/Hz. An analysis of the contribution of the residual noise from the Er:fiber optical frequency divider is also presented.

Quinlan, F; Kirchner, M S; Taylor, J A; Thorpe, M J; Lemke, N; Ludlow, A D; Jiang, Y; Oates, C W; Diddams, S A

2011-01-01

355

Effect of alcohol and divided attention task on simulated driving performance of young drivers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this study is to evaluate driving impairment linked to divided attention task and alcohol and determinate if it is higher for novice drivers compared to more experienced drivers. Sixteen novice drivers and sixteen experienced drivers participated in three experimental sessions corresponding to blood alcohol concentration [BAC] of 0.0 g/L, 0.2 g/L and 0.5 g/L. They performed a divided attention task [car-following task combined with a number parity identification task], and their re...

Freydier, Chloe?; Berthelon, Catherine; Bastien-toniazzo, Mireille; Gineyt, Guy

2013-01-01

356

Improvement of photomultiplier tube voltage divider ORTEC 269 for fast neutron time-of-flight spectrometer  

International Nuclear Information System (INIS)

Improvement of photomultiplier tube voltage divider ORTEC 269 for fast neutron time-of-flight spectrometer is described. As a result the performances of pulse-height, PSD (pulse shape discrimination) and timing resolution for neutron spectrometer have been greatly improved

1993-03-01

357

On Solutions of Holonomic Divided-Difference Equations on Nonuniform Lattices  

Directory of Open Access Journals (Sweden)

Full Text Available The main aim of this paper is the development of suitable bases that enable the direct series representation of orthogonal polynomial systems on nonuniform lattices (quadratic lattices of a discrete or a q-discrete variable. We present two bases of this type, the first of which allows one to write solutions of arbitrary divided-difference equations in terms of series representations, extending results given by Sprenger for the q-case. Furthermore, it enables the representation of the Stieltjes function, which has already been used to prove the equivalence between the Pearson equation for a given linear functional and the Riccati equation for the formal Stieltjes function. If the Askey-Wilson polynomials are written in terms of this basis, however, the coefficients turn out to be not q-hypergeometric. Therefore, we present a second basis, which shares several relevant properties with the first one. This basis enables one to generate the defining representation of the Askey-Wilson polynomials directly from their divided-difference equation. For this purpose, the divided-difference equation must be rewritten in terms of suitable divided-difference operators developed in previous work by the first author.

Salifou Mboutngam

2013-07-01

358

Self-calibration of divided circles on the basis of a prime factor algorithm  

International Nuclear Information System (INIS)

A new method for the self-calibration of divided circles is presented which is based on a known prime factor algorithm for the discrete Fourier transform (DFT). The method, called prime factor division (PFD) calibration, is of interest in angle metrology specially for self-calibrating angle encoders, and generally for a significant shortening of the cross-calibration between two divided circles. It requires that the circular division number N can be expressed as a product N = R × S, whereby the factors R and S are relatively prime integer numbers. For the self-calibration of a divided circle, N difference measurements between R angle positions in a regular distribution and one reference angle position determined by S are evaluated by a two-dimensional DFT, yielding the N absolute division errors. The factor R is preferably chosen small, down to a minimum of R = 2, whereas the factor S may be as large as appropriate for the division number N of interest. In the case of a cross-calibration between two divided circles, the PFD method reduces the number of measurements necessary from N2 to (R + 1) × N. Experimental results are demonstrated for the calibrations of an optical polygon with 24 faces (prime factor product 3 × 8) and a gearwheel with 44 teeth (prime factor product 4 × 11)

2008-01-01

359

The Effects of Divided Attention on Information Processing in Manual Tracking  

Science.gov (United States)

This research investigated the extent to which three suggested divided- attention effects--time delay, noise addition, and response bias change, as assessed by three cross-over-model parameters--were manifest when a manual, compensatory tracking task was performed concurrently with two secondary tasks. (Author/RK)

Wickens, Christopher D.

1976-01-01

360

Characterization of polyester with fiberglass materials as reinforcement in interior dividing walls  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Some synthetic fibers present better mechanical performance compared with the natural fibers. Therefor research works were carried out to focus the characterization of polyester and glass fibers to be used as reinforcements in the internal dividing walls. Results from polyester fabrics made of compression with or without fiberglass were obtained.

Santos, Tiago; Velosa, J. C.; Ramos, Lui?s F.; Fangueiro, Rau?l; Mendonc?a, Paulo

2012-01-01

 
 
 
 
361

Quantifying and Mapping the Digital Divide from an Internet Point of View  

Energy Technology Data Exchange (ETDEWEB)

Quantitative knowledge of the magnitude, extent and trends of the Digital Divide are critical to understand and identify the regions most in need of help, to make rational decisions on how to address the problems and to make cases for executives, funding agencies and politicians. We report on a project (PingER) to measure the Digital Divide from the point of view of Internet performance. The PingER project has been measuring Internet performance since 1995 and with the increased emphasis on measuring and tracking the Digital Divide, it now covers over 700 hosts in over 150 countries that between them contain over 99% of the world's Internet connected population. In this paper we will describe the how PingER works, it deployment, the data analysis, and presentation. We also introduce a new PingER visualization tool (ViPER) that provides a more appealing interactive visualization of the PingER data and also works on mobile PDAs. We will also show results from PingER that illustrate the magnitude, extent and trends for the Digital Divide, and also compare PingER results with some human development and technology indices.

Cottrell, R.Les; /SLAC; Khan, Shahryar; /NUST, Rawalpindi; Williams, Jerrod; /SLAC; Mehdi, Akbar; Kalim, Umar; Ali, Arshad; /NUST, Rawalpindi

2008-09-18

362

A new concept for spatially divided Deep Reactive Ion Etching with ALD-based passivation  

International Nuclear Information System (INIS)

Conventional Deep Reactive Ion Etching (DRIE) is a plasma etch process with alternating half-cycles of 1) Si-etching with SF6 to form gaseous SiFx etch products, and 2) passivation with C4F8 that polymerizes as a protecting fluorocarbon deposit on the sidewalls and bottom of the etched features. In this work we report on a novel alternative and disruptive technology concept of Spatially-divided Deep Reactive Ion Etching, S-DRIE, where the process is converted from the time-divided into the spatially divided regime. The spatial division can be accomplished by inert gas bearing 'curtains' of heights down to ?20 ?m. These curtains confine the reactive gases to individual (often linear) injection slots constructed in a gas injector head. By horizontally moving the substrate back and forth under the head one can realize the alternate exposures to the overall cycle. A second improvement in the spatially divided approach is the replacement of the CVD-based C4F8 passivation steps by ALD-based oxide (e.g. SiO2) deposition cycles. The method can have industrial potential in cost-effective creation of advanced 3D interconnects (TSVs), MEMS manufacturing and advanced patterning, e.g., in nanoscale transistor line edge roughness using Atomic Layer Etching.

2012-12-06

363

Can't surf, won't surf: The digital divide in mental health  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Background: New health information technology (HIT) increasingly plays a role in health care as technology becomes cheaper and more widespread. However, there is a danger that those who do not use or have access to technology will not benefit from HIT innovations, thus creating a “digital divide”.

Ennis, Liam; Rose, Diana; Denis, Mike; Pandit, Ninjeri; Wykes, Til

2012-01-01

364

Teaching across the Divide: Physical and Human Geographies of Hurricane Katrina  

Science.gov (United States)

This article critically reflects on our effort to "teach across the divide", by integrating physical and human geography in a new first-year course. We achieved this integration by structuring our course around a series of key events, in order to draw out the interaction of "natural" and "social" forces. After setting out the intellectual and…

Iveson, Kurt; Neave, Melissa

2010-01-01

365

Viscosity-induced crossing of the phantom divide in the dark cosmic fluid  

Directory of Open Access Journals (Sweden)

Full Text Available Choosing various natural forms for the equation-of-state parameter $w$ and the bulk viscosity $\\zeta$, we discuss how it is possible for a dark energy fluid to slide from the quintessence region across the divide $w=-1$ into the phantom region, and thus into a Big Rip future singularity.

IverHakonBrevik

2013-12-01

366

A Nonstationary Halley’s Iteration Method by Using Divided Differences Formula  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a new nonstationary iterative method for solving non linear algebraic equations that does not require the use of any derivative. The study uses only the Newton’s divided differences of first and second orders instead of the derivatives of (1.

Nasr Al Din Ide

2012-02-01

367

When Traders Enjoy Less Policy Risk: Divided Government, Economic Policy Change, and Stock Market Volatility in Germany, 1970-2005  

Digital Repository Infrastructure Vision for European Research (DRIVER)

How does divided government affect the probability of economic policy change, and thus policy risk on financial markets? In contrast to the standard balancing model we argue that divided government, i.e., partisan conflict between the executive and the legislative branches, negatively affects the possibility of economic policy change. Using a simple spatial model we demonstrate that one should expect divided government to increase the probability of policy gridlock. Since divided government r...

Roland Füss; Bechtel, Michael M.

2008-01-01

368

Resultados de la técnica de facoemulsificación "Divide y Vencerás" en la cirugía de catarata Results of the "Divide and Conquer"phacoemulsification technique in the cataract surgery  

Directory of Open Access Journals (Sweden)

Full Text Available OBJETIVO: Valorar la técnica de facoemulsificación de "Divide y Vencerás" en la cirugía del cristalino en el Centro de Microcirugía Ocular del Instituto Cubano de Oftalmología "Ramón Pando Ferrer". MÉTODOS: Se realizó una investigación aplicada retrospectiva y descriptiva en 102 ojos con diagnóstico de cataratas presenil y senil, de 52 pacientes que se les realizó facoemulsificación por la técnica de "Divide y Vencerás"en el Centro de Microcirugía Ocular del Instituto Cubano de Oftalmología "Ramón Pando Ferrer", en el período comprendido entre junio del 2006 a febrero del 2009. RESULTADOS: Se encontró que los mayores de 60 años representaron más de 75 % del total del universo estudiado. La mejor agudeza visual corregida en el posoperatorio mejoró a más de 0,7 en la escala de Snellen en el 85 % de los ojos. La diferencia del astigmatismo preoperatorio y posoperatorio fue 0,13 dioptrías. En la microscopia endotelial los cambios encontrados fueron de un 8,2 %, las complicaciones presentadas fueron de 2,8 %, ocurriendo con mayor frecuencia la rotura de cápsula posterior. CONCLUSIONES: Los mayores de 60 años representaron más de 75 % del total del universo estudiado, la agudeza visual corregida en el posoperatorio mejoró cuatro líneas en la escala de Snellen, el astigmatismo posoperatorio fue mínimo sin repercusión en la calidad visual de los pacientes, en la microscopia endotelial los cambios encontrados fueron mínimos y no tuvieron repercusión clínica para los pacientes, las complicaciones presentadas fueron muy bajas y se produjo con mayor frecuencia la rotura de cápsula posterior.OBJECTIVE:To assess the use of "Divide and Conquer" phacoemulsification technique in the lens surgery at the Ocular Microsurgery of "Ramón Pando Ferrer" Cuban Institute of Ophthalmology. METHODS: Retrospective and descriptive applied research was conducted in 102 eyes diagnosed with presenile and senile cataract from 52 patients who underwent "Divide and Conquer" phacoemulsification technique at the Ocular Microsurgery Center of "Ramón Pando Ferrer"from June 2006 to February 2009. RESULTS: It was found that patients over 60 years accounted for 75% of the universe of study; the best corrected visual acuity in the postoperative stage improved to more than 0,7 in the Snellen´s chart in 85% of the eyes, the difference between the preoperative and the postoperative astigmatism was 0,13 dioptries, the changes found in the endothelial microscopy represented 8,2%, the complications were observed in 2,8% of cases, being the most frequent the posterior capsule rupture. Ç CONCLUSIONS: The patients aged over 60 years accounted for 75% of the whole universe of study, the corrected visual acuity improved by four lines in the Snellen´s chart in the postoperative period, the postoperative astigmatism was minimal without any impact on the visual quality of the patients, there were minimal changes in the endothelial microscopy and no clinical impact was recorded. Complications were very low and the most frequent was the posterior chamber capsule rupture.

Juan Raúl Hernández Silva

2010-01-01

369

Resultados de la técnica de facoemulsificación "Divide y Vencerás" en la cirugía de catarata / Results of the "Divide and Conquer"phacoemulsification technique in the cataract surgery  

Scientific Electronic Library Online (English)

Full Text Available SciELO Cuba | Language: Spanish Abstract in spanish OBJETIVO: Valorar la técnica de facoemulsificación de "Divide y Vencerás" en la cirugía del cristalino en el Centro de Microcirugía Ocular del Instituto Cubano de Oftalmología "Ramón Pando Ferrer". MÉTODOS: Se realizó una investigación aplicada retrospectiva y descriptiva en 102 ojos con diagnóstico [...] de cataratas presenil y senil, de 52 pacientes que se les realizó facoemulsificación por la técnica de "Divide y Vencerás"en el Centro de Microcirugía Ocular del Instituto Cubano de Oftalmología "Ramón Pando Ferrer", en el período comprendido entre junio del 2006 a febrero del 2009. RESULTADOS: Se encontró que los mayores de 60 años representaron más de 75 % del total del universo estudiado. La mejor agudeza visual corregida en el posoperatorio mejoró a más de 0,7 en la escala de Snellen en el 85 % de los ojos. La diferencia del astigmatismo preoperatorio y posoperatorio fue 0,13 dioptrías. En la microscopia endotelial los cambios encontrados fueron de un 8,2 %, las complicaciones presentadas fueron de 2,8 %, ocurriendo con mayor frecuencia la rotura de cápsula posterior. CONCLUSIONES: Los mayores de 60 años representaron más de 75 % del total del universo estudiado, la agudeza visual corregida en el posoperatorio mejoró cuatro líneas en la escala de Snellen, el astigmatismo posoperatorio fue mínimo sin repercusión en la calidad visual de los pacientes, en la microscopia endotelial los cambios encontrados fueron mínimos y no tuvieron repercusión clínica para los pacientes, las complicaciones presentadas fueron muy bajas y se produjo con mayor frecuencia la rotura de cápsula posterior. Abstract in english OBJECTIVE:To assess the use of "Divide and Conquer" phacoemulsification technique in the lens surgery at the Ocular Microsurgery of "Ramón Pando Ferrer" Cuban Institute of Ophthalmology. METHODS: Retrospective and descriptive applied research was conducted in 102 eyes diagnosed with presenile and se [...] nile cataract from 52 patients who underwent "Divide and Conquer" phacoemulsification technique at the Ocular Microsurgery Center of "Ramón Pando Ferrer"from June 2006 to February 2009. RESULTS: It was found that patients over 60 years accounted for 75% of the universe of study; the best corrected visual acuity in the postoperative stage improved to more than 0,7 in the Snellen´s chart in 85% of the eyes, the difference between the preoperative and the postoperative astigmatism was 0,13 dioptries, the changes found in the endothelial microscopy represented 8,2%, the complications were observed in 2,8% of cases, being the most frequent the posterior capsule rupture. Ç CONCLUSIONS: The patients aged over 60 years accounted for 75% of the whole universe of study, the corrected visual acuity improved by four lines in the Snellen´s chart in the postoperative period, the postoperative astigmatism was minimal without any impact on the visual quality of the patients, there were minimal changes in the endothelial microscopy and no clinical impact was recorded. Complications were very low and the most frequent was the posterior chamber capsule rupture.

Hernández Silva, Juan Raúl; Villasol López, Ada Sonia; Ramos López, Meisy; Curbelo Cunill, Luis; Fernández Vásquez, Gilberto; Rio Torres, Marcelino.

370

Combining polyamine depletion with radiation therapy for rapidly dividing head and neck tumors: Strategies for improved locoregional control  

Energy Technology Data Exchange (ETDEWEB)

Locoregional control is adversely affected as clonogens from rapidly proliferating tumors repopulate during a course of radiation therapy. The cytostatic agent [alpha]-difluoromethylornithine (DFMO) was investigated for its capacity to slow proliferation kinetics in human squamous cell carcinomas (SSC) of the head and neck (H N), with the ultimate objective of improving locoregional control in rapidly dividing tumors treated with radiation therapy. Three human SSC cell lines established from primary H N tumors were evaluated in vitro (cell culture) and in vivo (SSC tumor xenografts in athymic mice) for the capacity of DFMO to induce growth inhibition. Flow cytometry analysis of SCC tumor growth kinetics and quantitative assessment of polyamine biosynthesis inhibition was performed to verify DFMO activity. DFMO effects on in vitro SSC radiosensitivity using clonogenic survival were also studied. A noncytotoxic exposure to DFMO (5mM [times] 72 hours) induced pronounced growth inhibition in all three SSC cell lines (70-90% at 7 days), and induced a 2-3 fold delay in volume doubling time for SCC tumor xenografts when administered orally in the drinking water (1.5%) to athymic mice. Kinetic analysis via flow cytometry confirmed that DFMO produced a lengthening of SCC cell cycle times, but did not alter in vitro radiosensitivity. Inhibition of ornithine decarboxylase (ODC) activity and depletion of endogenous polyamines (putrescine and spermidine), were confirmed in normal tissue (mouse skin) and in human SSC tumor xenografts of athymic mice receiving continuous oral DFMO. These data indicate that antiproliferative agents, such as DFMO, are capable of altering human SSC growth kinetics without altering intrinsic radiosensitivity. Such kinetic modulation may therefore provide a strategy to reduce the adverse impact of tumor cell proliferation during a radiotherapy treatment course for rapidly dividing tumors such as those in the H N. 33 refs., 5 figs., 3 tabs.

Petereit, D.G.; Harari, P.M.; Contreras, L.; Pickart, M.A.; Verma, A.K.; Kinsella, T.J. (Univ. of Wisconsin Comprehensive Cancer Center, Madison, WI (United States)); Gerner, E.W. (Univ. of Arizona Cancer Center, Tucson, AZ (United States))

1994-03-01

371

Combining polyamine depletion with radiation therapy for rapidly dividing head and neck tumors: Strategies for improved locoregional control  

International Nuclear Information System (INIS)

Locoregional control is adversely affected as clonogens from rapidly proliferating tumors repopulate during a course of radiation therapy. The cytostatic agent ?-difluoromethylornithine (DFMO) was investigated for its capacity to slow proliferation kinetics in human squamous cell carcinomas (SSC) of the head and neck (H ampersand N), with the ultimate objective of improving locoregional control in rapidly dividing tumors treated with radiation therapy. Three human SSC cell lines established from primary H ampersand N tumors were evaluated in vitro (cell culture) and in vivo (SSC tumor xenografts in athymic mice) for the capacity of DFMO to induce growth inhibition. Flow cytometry analysis of SCC tumor growth kinetics and quantitative assessment of polyamine biosynthesis inhibition was performed to verify DFMO activity. DFMO effects on in vitro SSC radiosensitivity using clonogenic survival were also studied. A noncytotoxic exposure to DFMO (5mM x 72 hours) induced pronounced growth inhibition in all three SSC cell lines (70-90% at 7 days), and induced a 2-3 fold delay in volume doubling time for SCC tumor xenografts when administered orally in the drinking water (1.5%) to athymic mice. Kinetic analysis via flow cytometry confirmed that DFMO produced a lengthening of SCC cell cycle times, but did not alter in vitro radiosensitivity. Inhibition of ornithine decarboxylase (ODC) activity and depletion of endogenous polyamines (putrescine and spermidine), were confirmed in normal tissue (mouse skin) and in human SSC tumor xenografts of athymic mice receiving continuous oral DFMO. These data indicate that antiproliferative agents, such as DFMO, are capable of altering human SSC growth kinetics without altering intrinsic radiosensitivity. Such kinetic modulation may therefore provide a strategy to reduce the adverse impact of tumor cell proliferation during a radiotherapy treatment course for rapidly dividing tumors such as those in the H ampersand N. 33 refs., 5 figs., 3 tabs

1994-03-01

372

The quantum divide why Schrödinger's cat is either dead or alive  

CERN Document Server

Using a selection of key experiments performed over the past 30 years or so, we present a discussion of the strikingly counter-intuitive phenomena of the quantum world that defy explanation in terms of everyday "common sense" reasoning, and we provide the corresponding quantum mechanical explanations with a very elementary use of associated formalism. Most, but certainly not all, of the experiments we describe are optical experiments involving a very small number of photons (particles of light). We begin with experiments on the wave-particle duality of electrons, proceed to experiments on the particle nature of light and single photon interference, delayed choice experiments and interaction-free detection, then go on to experiments involving the interference of two photons, quantum entanglement and Bell's Theorem, quantum teleportation, large-scale quantum effects and the divide between the classical and quantum worlds, addressing the question as to whether or not there is such a divide.

Gerry, Christopher C

2013-01-01

373

The household energy gap: examining the divide between habitual- and purchase-related conservation behaviours  

International Nuclear Information System (INIS)

This paper examines the conceptual divide between energy saving behaviours in the home, relating to purchase-oriented behaviours and habitual action to conserve energy. Considerable empirical research indicates that this divide is of utility when characterising energy saving behaviour. However, little attention has been focused around the association between energy saving behaviours and other environmental actions. Accordingly, this paper examines the structural bases of energy conservation behaviours in the wider context of environmental behaviour. These findings are then used to examine the characteristics of energy savers as they relate to other environmental actions. Using cluster analysis, the paper defines a range of behavioural characteristics that transcend energy saving and other environmental actions. The use of such an approach to policy makers seeking to encourage energy conservation practices is discussed at the end of the paper

2005-07-01

374

The household energy gap: examining the divide between habitual- and purchase-related conservation behaviours  

Energy Technology Data Exchange (ETDEWEB)

This paper examines the conceptual divide between energy saving behaviours in the home, relating to purchase-oriented behaviours and habitual action to conserve energy. Considerable empirical research indicates that this divide is of utility when characterising energy saving behaviour. However, little attention has been focused around the association between energy saving behaviours and other environmental actions. Accordingly, this paper examines the structural bases of energy conservation behaviours in the wider context of environmental behaviour. These findings are then used to examine the characteristics of energy savers as they relate to other environmental actions. Using cluster analysis, the paper defines a range of behavioural characteristics that transcend energy saving and other environmental actions. The use of such an approach to policy makers seeking to encourage energy conservation practices is discussed at the end of the paper.

Barr, Stewart E-mail: s.w.barr@exeter.ac.uk; Gilg, A.W.; Ford, Nicholas

2005-07-01

375

Photoreactivation of ultraviolet irradiated non-dividing populations of ICR 2A frog cells  

International Nuclear Information System (INIS)

Ultraviolet (UV) irradiation of non-dividing populations of ICR 2A frog cells led to their detachment from the surface of the culture dish and eventual lysis. Exposure of the cells to photoreactivating light after UV irradiation prevented cell killing and was accompanied by a loss of endonuclease sensitive sites from DNA. This photoreversal did not take place when the cells were exposed at 4"0C to photoreactivating light indicating that the reversal was the result of photoenzymatic repair. As the action of photoreactivating enzyme is specific for the repair of pyrimidine dimers in DNA, the results suggest that pyrimidine dimers in DNA are the critical lesions leading to the death of non-dividing populations of UV irradiated cells. (author)

1981-01-01

376

Generating Voronoi Diagrams for Curved Shapes with Divide-and-Conquer  

Science.gov (United States)

Voronoi diagrams have been used in many practical applications including solid modeling, Numerical Control machining, Finite Element mesh generation, etc. Investigating the properties of these diagrams is an active research topic with many fruitful results. Computational techniques for Voronoi diagrams, however, have been concentrated on low order elements, for points, lines, polygons, quadratic curves and surfaces. This paper presents a divide-and-conquer scheme computing the diagrams for planar shapes bounded by closed curves commonly encountered in Computer Aided Design. These curves include analytical curves and splines. The algorithm first divides the boundary curve into sections, delimited by curve points with the minimal curvatures. Bisector branches for these sections are then generated and merged recursively to obtain the final diagram. A detailed example in the paper shows the steps of the generation and merging of the bisectors. A simple analysis of the complexity of the algorithm is also presented.

Chou, Jin J.; George, Michael W. (Technical Monitor)

1996-01-01

377

On Typical Materials Acting as the Dividing Standard of the Development Stages of Human Substance Civilization  

Directory of Open Access Journals (Sweden)

Full Text Available During more than three million years, the substance civilization of human society went through the Stone Age, the Bronze Age, the Iron Age, the Steel and Cement Age, and the Silicon Age. At the beginning of the new century, the human society has entered into the Nanomaterials Age, which indicates that a completely new substance civilization of human society has started. This paper analyses and discusses why the typical materials serve as the only standard for dividing the eras of the substance civilization of human society. The author argues about the subject of dividing the substance civilization of human society. The goal is to initiate broad and thorough discussion of that subject so as to get a rather thorough understanding about it.

Bangwei Zhang

2012-06-01

378

Blurring the Computation-Communication Divide: Extraneous Memory Accesses and their Effects on MPI Intranode Communications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Modern MPI simulator frameworks assume the existence of a Computation-Communication Divide: thus, they model and simulate the computation and communication sections of an MPI Program separately. The assumption is actually sound for MPI processes that are situated in different nodes and communicate through a network medium such as Ethernet or Infiniband. For processes that are within a node however, the validity of the assumption is limited since the processes communicate using shared memory, ...

Tan, Wilson M.; Jarvis, Stephen A.

2012-01-01

379

Application of the hybrid multiobjective optimization methods on the capacitive voltage divider  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents application of multiobjective optimization methods on a capacitive divider finite element model. Modeling is based on the differential evolution algorithm (DE), including the concept of the Pareto nondominance. Through calculations, this concept allows differential evolution algorithm variation in order to achieve uniformly distributed results on the Pareto front, including the lowest population size as possible. Selection step, as a part of the differential evolution meth...

Kitak, Peter; Tic?ar, Igor; Pihler, Joz?e; Glotic?, Adnan; Popovic?, Jelena; Biro?, Oszkar; Preis, Kurt

2012-01-01

380

Design and Modeling of Symmetric Three Branch Polymer Planar Optical Power Dividers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Two types of polymer-based three-branch symmetric planar optical power dividers (splitters) were designed, multimode interference (MMI) splitter and triangular shape-spacing splitter. By means of modeling the real structures were simulated as made of Epoxy Novolak Resin on silicon substrate, with silica buffer layer and polymethylmethacrylate as protection cover layer. The design of polymer waveguide structure was done by Beam Propagation Method. After comparing properties of both types of th...

Prajzler, V.; Tuma, H.; Spirkova, J.; Jerabek, V.

2013-01-01

 
 
 
 
381

E-GOVERNMENT AND GENDER DIGITAL DIVIDE: THE CASE OF JORDAN  

Digital Repository Infrastructure Vision for European Research (DRIVER)

There is an indicator that e-Government projects have gabs in dealing with gender digital divide especially in developing countries and rural areas in industrialized countries. This research aims to review experiences on integration of gender equality issues with e-Government projects all over the world, and introduce justifications for the need of poor women to access e-Government information and services. Jordan embarked on many initiatives that are related to women and rural areas developm...

2010-01-01

382

Force generation in dividing E. coli cells: A handles-on approach using optical tweezers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In bacteria, what ‘drives’ the process of cell division is unknown. Possibly, forces generated by an internal protein ring (termed ‘the Z-ring’) are responsible for the division process, but direct evidence is lacking. Here we describe the development of a method to measure forces in a single dividing bacterium. Using optical tweezers, forces can be measured on optically trapped micron-sized beads. To attach such a bead to a living bacterium, one of its outer membrane proteins is engi...

Verhoeven, Gertjan Sebastiaan

2008-01-01

383

Cortical microtubule labeling: Insight of AFH14 in non-dividing cells  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We recently reported that AFH14 participated in microtubule and actin filament interaction in cell division, and the AFH14 (FH1FH2) was important to the directly binding activity of microtubules and microfilaments. To preliminarily understand the function and localization of AFH14 in non-dividing cells, we overexpressed FH1FH2-RFP in onion epidermal cells, and found a fluorescence labeled filamentous network. The result of double labeling with different cytoskeleton reporter proteins indicate...

2010-01-01

384

Impact of the digital divide on information literacy training in a higher education context  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper reports on a master’s study undertaken to investigate the impact of the digital divide on information literacy(IL) training of Extended Curriculum Programme (ECP) students at the Durban University of Technology (DUT). Since1994 the demographics of higher education institutions in South Africa have changed. Today these institutions compriseheterogeneous groups of students, by race, economic background, digital background, etc. and consequently with different

2012-01-01

385

An improved capacitive divider probe for plasma potential measurements in the Phaedrus tokamak  

International Nuclear Information System (INIS)

High bandwidth capacitive probes are useful tools for potentials measurements in the tokamak scrape off layer. An improved capacitive divider probe design with very high frequency bandwidth is shown. The gain of this system is between 0 and -8 dB for frequencies from 0.1 Hz to more than 100 MHz, with the -3 dB point at approximately 40 MHz. The probe structure, circuits, performance, and experimental results from the Phaedrus-T tokamak are given

1991-01-01

386

Maximum Likelihood-Based Iterated Divided Difference Filter for Nonlinear Systems from Discrete Noisy Measurements  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A new filter named the maximum likelihood-based iterated divided difference filter (MLIDDF) is developed to improve the low state estimation accuracy of nonlinear state estimation due to large initial estimation errors and nonlinearity of measurement equations. The MLIDDF algorithm is derivative-free and implemented only by calculating the functional evaluations. The MLIDDF algorithm involves the use of the iteration measurement update and the current measurement, and the iteration terminatio...

Changyuan Wang; Jing Zhang; Jing Mu

2012-01-01

387

NASA's S'COOL Project: Bridging the Divide Between the 'Real' World and the Classroom  

Science.gov (United States)

In an effort to bridge the gap between scientific research, teacher instruction and student learning, the CERES Students Cloud Observations On-Line (S'COOL) Project offers a unique perspective on how to narrow the divide between the real world and the classroom. Reality-based learning has become a staple in the education of our youth and the S'COOL Project has taken this concept one step further.

Sepulveda, Roberto; Chambers, Lin H.

2004-01-01

388

Mobile Phones Bridging the Digital Divide for Teens in the US?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In 2009, just 27% of American teens with mobile phones reported using their devices to access the internet. However, teens from lower income families and minority teens were significantly more likely to use their phones to go online. Together, these surprising trends suggest a potential narrowing of the digital divide, offering internet access to those without other means of going online. This is an important move, as, in today’s society, internet access is central to active citizenship in ...

2011-01-01

389

Test Time Reduction for BIST by Parallel Divide-and-Conquer Method  

Energy Technology Data Exchange (ETDEWEB)

BIST(Built-in Self Test) has been considered as the most promising DFT(design-for-test) scheme for the present and future test strategy. The most serious problem in applying BIST(Built-in Self Test) into a large circuit is the excessive increase in test time. This paper is focused on this problem. We proposed a new BIST construction scheme which uses a parallel divide-and-conquer method. The circuit division is performed with respect to some internal nodes called test points. The test points are selected by considering the nodal connectivity of the circuit rather than the testability of each node. The test patterns are generated by only one linear feedback shift register(LFSR) and they are shared by all the divided circuits. Thus, the test for each divided circuit is performed in parallel. Test responses are collected from the test point as well as the primary outputs. Even though the divide-and-conquer scheme is used and test patterns are generated in one LFSR, the proposed scheme does not lose its pseudo-exhaustive property. We proposed a selection procedure to find the test points and it was implemented with C/C{sup ++} language. Several example circuits were applied to this procedure and the results showed that test time was reduced upto 1/2{sup 1}51 but the increase in the hardware overhead or the delay increase was not much high. Because the proposed scheme showed a tendency that the increasing rates in hardware overhead and delay overhead were less than that in test time reduction as the size of circuit increases, it is expected to be used efficiently for large circuits as VLSI and ULSI. (author). 15 refs., 7 figs., 5 tabs.

Choi, Byung Gu; Kim, Dong Wook [Kwangwoon University (Korea)

2000-06-01

390

So far Left, we're Right": bridging the cultural divide in California's stem cell controversy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the United States, the ideological divide between Left/Right, or ‘progressive/conservative’ has been predominantly defined by the abortion issue since its decriminilization in 1973. Feminists who fought that long battle for reproductive rights have been compelled to protect them against political retrenchment. By 2000, human embryonic stem cell research (hESCR) had eclipsed abortion as the point of resistance for right-to-life activists. While aversion to embryo experimentation is not ...

2010-01-01

391

Divided we stand - unified we govern? Cohabitation and regime voting in the 2002 French elections  

Digital Repository Infrastructure Vision for European Research (DRIVER)

"In this article the impact of voters' regime preferences, i.e. their preferences for either divided or unified government, on their voting behaviour, is analysed. The theory expounded, combining behavioural as well as institutional approaches, predicts that voters weigh their regime against their partisan preferences to derive their vote choice. This theory and its implications are tested on the 2002 French legislative elections using a multinomial logit set-up. The results indicate that reg...

Gschwend, Thomas; Leuffen, Dirk

2005-01-01

392

Divided attention 5 to 10 years after severe closed head injury.  

Science.gov (United States)

The ability to divide attention of persons who had sustained a severe Closed Head Injury 5 to 10 years before (chronic CHI patients), was examined in a dual-task experiment administered to 15 CHI patients and 34 control subjects. Both the patient group and the control group consisted of active licenced drivers at the time of the investigation. One task was a compensatory tracking task requiring lane tracking, a basic skill or car driving. The other task was a self-paced visual choice reaction time task. Single-task difficulty was individually adjusted by adaptive task procedures (on both tasks CHI patients reached significantly lower performance levels in single task conditions). With individual differences in single-task performance thus controlled, the ability to divide attention was found to be approximately equal in the chronic CHI patients and the control group. A surprising finding in this light, however, was the significant positive correlation between severity of injury (PTA duration) and divided attention costs in the patient group. PMID:2758848

Brouwer, W H; Ponds, R W; Van Wolffelaar, P C; Van Zomeren, A H

1989-06-01

393

Poor-Rich Divide in Aravind Adiga’s The White Tiger  

Directory of Open Access Journals (Sweden)

Full Text Available Aravind Adiga’s The White Tiger, which was awarded theMan Booker Prize in 2008, is singular in its fictionalized portrayal of the relationship between Balram Halwai and his master Mr Ashok. The story exposes the poor-rich divide that surrounds India in the backdrop of economic prosperity, in the wake of the IT revolution. As Michael Portillo commented the novel “shocked and entertained in equal measure” (Portillo, 2008. Written in the epistolary form, the novel is a seven-part letter to the Chinese Premier, Wen Jiabao, from Balram alias Ashok Sharma, a self-styled ‘Thinking Man / And an entrepreneur’ (TWT, 2008, p. 3. Balram the killer, metamorphoses into his master’s replica after his heinous crime. By crime and cunning, in the name of the social injustice due to existing rich-poor divide in India, Balram rules his entrepreneurial world. This paper attempts to trace the great poor-rich divide manifested through The White Tiger, having dangerous consequences, if unresolved.

A.J. Sebastian

2009-05-01

394

Heat control in HVDC resistive divider by PID and NN controllers  

International Nuclear Information System (INIS)

In this study, a control system is presented that is devised to increase measurement precisions within a prototype high voltage DC resistive divider (HVDC-RD). Since one of the major sources of measurement errors in such devices is the self heating effect, a system controlling the temperature within the high voltage DC resistive divider is devised so that suitable and stable temperature conditions are maintained that, in return, will decrease the measurement errors. The resistive divider system is cooled by oil, and PID and neural network (NN) controllers try to keep the temperature within the prescribed limits. The system to be controlled exhibits a nonlinear character, and therefore, a control approach based on NN controllers is proposed. Thus, a system that can fulfill the various requirements dictated by the designer is constructed. The performance of the NN controller is compared with that of the PID controller developed for the same purpose, and the values of the performance indices indicate the superiority of the NN controller over that of the classical PID controller

2007-10-01

395

Heat control in HVDC resistive divider by PID and NN controllers  

Energy Technology Data Exchange (ETDEWEB)

In this study, a control system is presented that is devised to increase measurement precision within a prototype high voltage DC resistive divider (HVDC-RD). Since one of the major sources of measurement errors in such devices is the self heating effect, a system controlling the temperature within the high voltage DC resistive divider is devised so that suitable and stable temperature conditions are maintained that, in return, will decrease the measurement errors. The resistive divider system is cooled by oil, and PID and neural network (NN) controllers try to keep the temperature within the prescribed limits. The system to be controlled exhibits a nonlinear character, and therefore, a control approach based on NN controllers is proposed. Thus, a system that can fulfill the various requirements dictated by the designer is constructed. The performance of the NN controller is compared with that of the PID controller developed for the same purpose, and the values of the performance indices indicate the superiority of the NN controller over that of the classical PID controller. (author)

Yilmaz, S.; Dincer, H. [Kocaeli University, Engineering Faculty, Department of Electronics and Communications Engineering, Veziroglu Campus, 41040 Kocaeli (Turkey); Eksin, I. [Control Engineering Program, Department of Electrical Engineering, Electrical and Electronics Engineering Faculty, Istanbul Technical University, 34469 Istanbul (Turkey); Kalenderli, O. [Electrical Engineering Program, Department of Electrical Engineering, Electrical and Electronics Engineering Faculty, Istanbul Technical University, 34469 Istanbul (Turkey)

2007-10-15

396

Applications of the complexity space to the General Probabilistic Divide and Conquer Algorithms  

Science.gov (United States)

Schellekens [M. Schellekens, The Smyth completion: A common foundation for denotational semantics and complexity analysis, in: Proc. MFPS 11, in: Electron. Notes Theor. Comput. Sci., vol. 1, 1995, pp. 535-556], and Romaguera and Schellekens [S. Romaguera, M. Schellekens, Quasi-metric properties of complexity spaces, Topology Appl. 98 (1999) 311-322] introduced a topological foundation to obtain complexity results through the application of Semantic techniques to Divide and Conquer Algorithms. This involved the fact that the complexity (quasi-metric) space is Smyth complete and the use of a version of the Banach fixed point theorem and improver functionals. To further bridge the gap between Semantics and Complexity, we show here that these techniques of analysis, based on the theory of complexity spaces, extend to General Probabilistic Divide and Conquer schema discussed by Flajolet [PE Flajolet, Analytic analysis of algorithms, in: W. Kuich (Ed.), 19th Internat. Colloq. ICALP'92, Vienna, July 1992; Automata, Languages and Programming, in: Lecture Notes in Comput. Sci., vol. 623, 1992, pp. 186-210]. In particular, we obtain a general method which is useful to show that for several recurrence equations based on the recursive structure of General Probabilistic Divide and Conquer Algorithms, the associated functionals have a unique fixed point which is the solution for the corresponding recurrence equation.

García-Raffi, L. M.; Romaguera, S.; Schellekens, M. P.

2008-12-01

397

Inequalities and the digital divide in children and young people's internet use: findings from the UK Children Go Online project  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Executive summary. Considerable academic and policy attention has recently addressed the so-called ‘digital divide’ in the UK and elsewhere. Yet very little research has addressed children and young people in relation to the digital divide. This report examines the extent and source of any inequalities in internet access and use among 9-19 year olds in the UK. Drawing on data from the ‘UK Children Go Online’ project, we ask: • Is there is digital divide among children and young peop...

Livingstone, Sonia; Bober, Magdalena; Helsper, Ellen

2005-01-01

398

Mapping and explaining the use of the left-right divide  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english This study is about mapping and explaining the use of the Left-Right divide across 14 countries from 5 Continents and relies on the richness of the post electoral mass surveys from the Comparative National Election Project: 14 countries and 18 elections spread over 5 continents. The paper shows not [...] only how extensively the LR divide is used in these 14 countries, but also explains variation across both individuals and countries in terms of the factors determining LR recognition and use. Overall, it is shown that, although seen world-wide, the LR divide (both for self-placement and party placement) is more present in long consolidated and middle-aged democracies and countries with freer media systems than in new democracies and societies with less free media systems. In the case of parties LR placement, party size also counts: larger parties are more easily placed. Additionally, we also show that LR recognition is more socially and politically determined in long consolidated and middle-aged democracies and in countries with more freedom of the press than in new democracies and in systems with less free media system. These findings add to the existing knowledge about these topics because previous studies were either country/Continent specific, or, if global in nature, never invested in explaining individual and system variation across 14 from 5 Continents. Besides, these findings mean that in the long term probably the new democracies will converge with the long consolidated or middle-aged ones, but this is an empirical question to be researched in future studies.

André, Freire; Kats, Kivistik.

399

ODL and the Impact of Digital Divide on Information Access in Botswana  

Directory of Open Access Journals (Sweden)

Full Text Available Open and distance learning (ODL has created room for the emergence of virtual education. Not only are students found everywhere and anywhere undertaking their studies and earning their degrees, but geographical boundaries between nations no longer appear to have much relevance. As the new education paradigm irretrievably alters the way teaching and learning is conducted, the application of modern educational ICTs has a major role to play.With students of transnational or cross-border education dispersed into various nooks and crannies of Botswana, many others enlist for the “home-baked” distance learning programmes from their diverse locations. Like the face-to-face conventional students, distance learners also have information needs which have to be met. But blocking the distance learners’ realization of their information needs is the digital divide, which further marginalizes the underclass of “info-poor.”The survey method was used, and a questionnaire administered to 519 students of four tertiary level distance teaching institutions that met the criteria set for the study yielded a 70.1% response rate. The results showed that while the Government of Botswana has made considerable effort to ensure country-wide access to ICT, which now constitutes an effective instrument for meeting information needs, a number of problems still exist. The factors impeding easy access are unearthed. The findings of an empirical study portraying some learners as information-rich and others as information-poor, and the consequence of distance learners studying on both sides of the digital divide, are discussed. Suggestions on bridging the digital divide are offered.

Olugbade Oladokun

2011-10-01

400

Consumer groups divided over benefits of lower payment-card fees | EurActiv  

...Consumer groups divided over benefits of lower payment-card fees | EurActiv MIFs) to be published simultaneously. EU news & policy debates- across ...PSD II) this month, with a separate regulation on multilateral interchange fees (MIFs) to be published simultaneously. The draft proposal, seen ... MIFs are charges paid by a retailerrsquo;s bank for processing a payment card transaction. Retailers usually incorporate the fee as a ... ldquo;Whether the price of the goods will decrease when MIFs are lowered depends on retailers,rdquo; said Monique Goyens, director-general ...

 
 
 
 
401

Mitosis Through the Microscope: Advances in Seeing Inside Live Dividing Cells  

Science.gov (United States)

This article discusses advances made in the study of mitosis. The most visually spectacular events in the life of a cell occur when it divides. This is especially true in higher eukaryotes, where the size and geometry of cells allow the division process to be followed through a microscope with considerable clarity. In these organisms, the membrane surrounding the nucleus breaks down after the replicated DNA has condensed to form discrete chromosomes. Several new structures are then assembled to separate the chromosomes and partition the cytoplasm into two separate cells.

Conly Rieder (USA. Marine Biology Laboratory;Lab of Cell Regulation, Division of Molecular Medicine, Wadsworth Center); Alexey Khodjakov (USA. Marine Biology Laboratory;Lab of Cell Regulation, Division of Molecular Medicine, Wadsworth Center)

2003-04-04

402

eGY-Africa: Addressing the Digital Divide for Science in Africa  

Energy Technology Data Exchange (ETDEWEB)

Adoption of information and communication technologies and access to the Internet is expanding in Africa, but because of the rapid growth elsewhere, a Digital Divide between Africa and the rest of the world exists, and the gap is growing. In many sub-Saharan African countries, education and research sector suffers some of the worst deficiencies in access to the Internet, despite progress in development of NRENs - National Research and Education (cyber) Networks. By contrast, it is widely acknowledged in policy statements from the African Union, the UN, and others that strength in this very sector provides the key to meeting and sustaining Millennium Development Goals. Developed countries with effective cyber-capabilities proclaim the benefits to rich and poor alike arising from the Information Revolution. This is but a dream for many scientists in African institutions. As the world of science becomes increasingly Internet-dependent, so they become increasingly isolated. eGY-Africa is a bottom-up initiative by African scientists and their collaborators to try to reduce this Digital Divide by a campaign of advocacy for better institutional facilities. Four approaches are being taken. The present status of Internet services, problems, and plans are being mapped via a combination of direct measurement of Internet performance (the PingER Project) and a questionnaire-based survey. Information is being gathered on policy statements and initiatives aimed at reducing the Digital Divide, which can be used for arguing the case for better Internet facilities. Groups of concerned scientists are being formed at the national, regional levels in Africa, building on existing networks as much as possible. Opinion in the international science community is being mobilized. Finally, and perhaps most important of all, eGY-Africa is seeking to engage with the many other programs, initiatives, and bodies that share the goal of reducing the Digital Divide - either as a direct policy objective, or indirectly as a means to an end, such as the development of an indigenous capability in science and technology for national development. The expectation is that informed opinion from the scientific community at the institutional, national, and international levels can be used to influence the decision makers and donors who are in a position to deliver better Internet capabilities.

Barton, C.E.; /Australian Natl. U., Canberra; Amory-Mazaudier, C.; /Lab.Phys.Plasmas, Saint Maur des Fosses; Barry, B.; /Assoc.African Univ., Accra; Chukwuma; /Olabisi Onabanjo U.; Cottrell, R.L.; /SLAC; Kalim, U.; /Pakistan Natl. U.; Mebrahtu, A.; /Mekelle U.; Petitdidier, M.; /Lab. d' Atmos., Velizy; Rabiu, B.; /Federal Tech. U., Akure; Reeves, C.; /Earthworks bv, Delft

2010-06-16

403

Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2014 January-March  

Science.gov (United States)

Lightcurves for 40 main-belt asteroids were obtained at the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) from 2014 January through March. The majority of the objects were members of the Hungaria group/family. In many cases, the observations were follow-up to previous apparitions to check for the possibility of undiscovered satellites or to provide additional data for spin axis and shape modeling. One Hungaria, 5175 Ables, showed indications of a satellite in the form of having two periods. However, there were no decisive observations of mutual events due to a satellite. This makes the asteroid a possible, but not probable, binary.

Warner, Brian D.

2014-07-01

404

David Sanders. A Divided Poet: Robert Frost, North of Boston, and the Drama of Disappearance.  

Directory of Open Access Journals (Sweden)

Full Text Available David Sanders in his monograph entitled A Divided Poet: Robert Frost, North of Boston, and the Drama of Disappearance (2011 sheds light on the dilemmas, doubts and personal conflicts Frost confronted while composing his poetic collection North of Boston in which some of his most well-known lyrics, such as “Mending Wall,” “After Apple-Picking,” and “The Wood-Pile,” are contained. This book should be considered alongside a number of other publications either in monograph or essay form that app...

Tatiani G. Rapatzikou

2012-03-01

405

Past Accumulation Rates of the Western Antarctic Ice Sheet Near an Ice Divide  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The study of accumulation rates of ice is a direct link to the evolution of ice sheet. It is believed by scientists that ice sheet evolution will aid in the mystery of climate change and may lead to predictions about climates in the future. This dissertation focuses on studying the accumulation rates of ice within the Western Antarctic Ice Sheet near an ice divide. The site of study is located just near Subglacial Lake Ellsworth. Radio Echo Sounding (RES) data was collected to measure the dep...

Child, Sarah

2009-01-01

406

Divide and ProsPer: the emerging role of PtdIns3P in cytokinesis.  

Science.gov (United States)

Cytokinesis is the final step of cell division whereby the dividing cells separate physically. Failure of this process has been proposed to cause tumourigenesis. Several specific lipids are essential for cytokinesis, and recent evidence has revealed that phosphatidylinositol 3-phosphate (PtdIns3P) - a well-known regulator of endosomal trafficking, receptor signaling, nutrient sensing and autophagy - plays an evolutionarily conserved role during cytokinesis. The emerging picture is that PtdIns3P and its regulators and effectors constitute a novel regulatory mechanism for cytokinesis. Elucidating the role of PtdIns3P in cytokinesis might contribute to insight into mechanisms of tumour development and suppression. PMID:20880709

Nezis, Ioannis P; Sagona, Antonia P; Schink, Kay Oliver; Stenmark, Harald

2010-11-01

407

MEPs divided ahead of vote on medical devices | EurActiv  

...MEPs divided ahead of vote on medical devices | EurActiv The European Commission has tabled new rules for the approval of medical devices ...to how far the proposal should go in harmonising the way medical devices should be approved in future. special-report-medical-devices-regulation,health,medical devices EU ...The EU's strategy under review The battle for EU consumer rights Medical Devices: A new regulatory landscape Consumers: Buying green? Nutrition ... UN Development Goals: Countdown to 2015 Payments services directive II Medical devices regulation Building the way out of the crisis Future of aviation: ...

408

Military-Entrepreneur Relations in China since 1979: From Political Divide to Social Reconciliation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

There have been substantial changes in the relationship between the PLA and the emerging private entrepreneurs since China’s reform and opening-up. As a consequence, these relations have shifted from the old model of political divide to a new mod...

Yongchang Wang

2009-01-01

409

Arnol'd tongues for a resonant injection-locked frequency divider: analytical and numerical results  

DEFF Research Database (Denmark)

In this paper we consider a resonant injection-locked frequency divider which is of interest in electronics, and we investigate the frequency locking phenomenon when varying the amplitude and frequency of the injected signal. We study both analytically and numerically the structure of the Arnolâ??d tongues in the frequencyâ??amplitude plane. In particular, we provide exact analytical formulae for the widths of the tongues, which correspond to the plateaux of the devilâ??s staircase picture. The results account for numerical and experimental findings presented in the literature for special driving terms and, additionally, extend the analysis to a more general setting.

Bartuccelli, Michele; Deane, Jonathan H.B.

2010-01-01

410

Controls on the movement and composition of firn air at the West Antarctic Ice Sheet Divide  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We sampled interstitial air from the perennial snowpack (firn) at a site near the West Antarctic Ice Sheet Divide (WAIS-D) and analyzed the air samples for a wide variety of gas species and their isotopes. We find limited convective influence (1.4–5.2 m, depending on detection method) in the shallow firn, gravitational enrichment of heavy species throughout the diffusive column in general agreement with theoretical expectations, a ~10 m thick lock-in zone beginning at ~67 m, and a total fir...

Battle, M. O.; Severinghaus, J. P.; Sofen, E. D.; Plotkin, D.; Orsi, A. J.; Aydin, M.; Montzka, S. A.; Sowers, T.; Tans, P. P.

2011-01-01

411

Ice Elevation Near the West Antarctic Ice Sheet Divide During the Last Glaciation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Interior ice elevations of the West Antarctic Ice Sheet (WAIS) during the last glaciation, which can serve as benchmarks for ice-sheet models, are largely unconstrained. Here we report past ice elevation data from the Ohio Range, located near the WAIS divide and the onset region of the Mercer Ice Stream. Cosmogenic exposure ages of glacial erratics that record a WAIS highstand similar to 125 m above the present surface date to similar to 11.5 ka. The deglacial chronology prohibits an interior...

Borns, Harold W.; Parizek, Byron R.; Mukhopadhyay, Sujoy; Ackert, Robert P. Jr

2007-01-01

412

Evaluation of [[sup 11]C]thymidine for measurement of cell proliferation in fast dividing tissues  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this study was to investigate the possibility of using [[sup 11]C]thymidine as a tumor marker for positron emission tomography studies. Biodistribution studies were set up to investigate the in vivo behavior of [[sup 11]C]thymidine. Simultaneously. the DNA incorporation in fast dividing tissues and catabolism was studied. Our results confirm that [[sup 11]C]thymidine can be used for detection of cell proliferation of positron emission tomography. As such, it can produce supplementary information in cancer research. (author).

Poupeye, E.M.; Leenheer, A.P. De (Ghent Rijksuniversiteit (Belgium)); Goethals, P.P.; Dams, R.F. (Ghent State Univ. (Belgium). Lab. of Analytical Chemistry); Eijkeren, M.E. Van (University Hospital, Ghent (Belgium). Dept. of Radiotherapy and Nuclear Medicine)

1993-04-01

413

Evaluation of [11C]thymidine for measurement of cell proliferation in fast dividing tissues  

International Nuclear Information System (INIS)

The purpose of this study was to investigate the possibility of using [11C]thymidine as a tumor marker for positron emission tomography studies. Biodistribution studies were set up to investigate the in vivo behavior of [11C]thymidine. Simultaneously. the DNA incorporation in fast dividing tissues and catabolism was studied. Our results confirm that [11C]thymidine can be used for detection of cell proliferation of positron emission tomography. As such, it can produce supplementary information in cancer research. (author)

1993-04-01

414

Evaluation of [11C]thymidine for measurement of cell proliferation in fast dividing tissues.  

Science.gov (United States)

The purpose of this study was to investigate the possibility of using [11C]thymidine as a tumor marker for positron emission tomography studies. Biodistribution studies were set up to investigate the in vivo behavior of [11C]thymidine. Simultaneously, the DNA incorporation in fast dividing tissues and catabolism was studied. Our results confirm that [11C]thymidine can be used for detection of cell proliferation by positron emission tomography. As such, it can produce supplementary information in cancer research. PMID:8485496

Poupeye, E M; Goethals, P P; Dams, R F; De Leenheer, A P; van Eijkeren, M E

1993-04-01

415

Phase stabilization of a wave-front dividing four-beam combined amplifier with stimulated Brillouin scattering phase conjugate mirrors  

Science.gov (United States)

Beam combining method is a promising technique for achieving energy scaling of solid-state lasers. The key technique of the coherent beam combining is the phase control of the stimulated Brillouin scattering wave. In previous works, the amplitude dividing scheme has shown more effective phase control than the wave-front dividing scheme. A recent experiment demonstrated that the phase stabilization in the wave-front dividing scheme can be improved by reducing the beam pointing fluctuation. In this work, a phase stabilization experiment is performed with the wave-front dividing four-beam combined amplifier. The phases are stabilized within ?/25 with an amplified gain of 5.25.

Shin, Jae Sung; Park, Sangwoo; Kong, Hong Jin; Yoon, Jin Woo

2010-03-01

416

Freshwater as shared between society and ecosystems: from divided approaches to integrated challenges.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper has its focus on water's key functions behind ecosystem dynamics and the water-related balancing involved in a catchment-based ecosystem approach. A conceptual framework is being developed to address fundamental trade-offs between humans and ecosystems. This is done by paying attention to society's unavoidable landscape modifications and their unavoidable ecological effects mediated by water processes. Because the coevolution of societal and environmental processes indicates resonan...

Falkenmark, Malin

2003-01-01

417

Aeromagnetic evidence for a volcanic caldera(?) complex beneath the divide of the West Antarctic Ice Sheet  

Science.gov (United States)

A 1995-96 aeromagnetic survey over part of the Sinuous Ridge (SR) beneath the West Antarctic Ice Sheet (WAIS) divide shows a 70-km diameter circular pattern of 400-1200-nT anomalies suggesting one of the largest volcanic caldera(?) complexes on earth. Radar-ice-sounding (RIS) shows the northern part of this pattern overlies the SR, and extends south over the Bentley Subglacial Trench (BST). Modeled sources of all but one the caldera(?) anomalies are at the base of Antarctic Ice Sheet (WAIS) divide shows a 70-km diameter circular pattern of 400-1200-nT anomalies suggesting one of the largest volcanic caldera(?) complexes on earth. Radar-ice-sounding (RIS) shows the northern part of this pattern overlies the SR, and extends south over the Bentley Subglacial Trench (BST). Modeled sources of all but one the caldera(?) anomalies are at the base of < 1-2-km thick ice and their volcanic edifices have been glacially removed. The exception is a 700-m high, 15-km wide 'volcano' producing an 800-nT anomaly over the BST. 'Intrusion' of this 'volcano' beneath 3 km of ice probably resulted in pillow basalt rather than easily removed hyaloclastite erupted beneath thinner ice. The background area (-300 to -500-nT) surrounding the caldera(?) is possibly caused by a shallow Curie isotherm. We suggest uplift of the SR forced the advance of the WAIS.

Behrendt, J. C.; Finn, C. A.; Blankenship, D.; Bell, R. E.

1998-01-01

418

The influence of thematic congruency, typicality and divided attention on memory for radio advertisements.  

Science.gov (United States)

We examined the effects of the thematic congruence between ads and the programme in which they are embedded. We also studied the typicality of the to-be-remembered information (high- and low-typicality elements), and the effect of divided attention in the memory for radio ad contents. Participants listened to four radio programmes with thematically congruent and incongruent ads embedded, and completed a true/false recognition test indicating the level of confidence in their answer. Half of the sample performed an additional task (divided attention group) while listening to the radio excerpts. In general, recognition memory was better for incongruent ads and low-typicality statements. Confidence in hits was higher in the undivided attention group, although there were no differences in performance. Our results suggest that the widespread idea of embedding ads into thematic-congruent programmes negatively affects memory for ads. In addition, low-typicality features that are usually highlighted by advertisers were better remembered than typical contents. Finally, metamemory evaluations were influenced by the inference that memory should be worse if we do several things at the same time. PMID:23947823

Martín-Luengo, Beatriz; Luna, Karlos; Migueles, Malen

2014-10-01

419

Recovery response of dividing cells in the thymus of whole-body ?-irradiated mice  

International Nuclear Information System (INIS)

Mice were irradiated with different doses of ?-rays 30 min after the administration of 32P-orthophosphate. The dose-response curves determined at 72 hours after exposure showed an inflection point in the total activity present in the DNA in thymus and spleen. In the low dose-range, the dose-response curves have D0 = 55 rad(n = 2.5) for thymus and D0 = 95 rad (n = 2.5) for the spleen. Thirty minutes after the administration of 32P-orthophosphate, the dividing cells from thymus were partially synchronized by the administration of 80 mg per kg body-weight hydroxyurea. At different time-intervals, the mice were irradiated with 80 rad, and the total activity of DNA was determined at 72 hours after synchronization. A significant maximum of recovery was found at 5 hours (S phase) after the administration of hydroxyurea. In similar conditions, the dose-response curves corresponding to the G1, S and M phase of the division cycle were also determined. The synchronization of dividing cells induced by hydroxyurea failed in the spleen. (author)

1976-01-01

420

Power combiners/dividers for loop pickup and kicker arrays for FNAL stochastic cooling rings  

Energy Technology Data Exchange (ETDEWEB)

The anti-proton accumulator and debuncher at FNAL will use stochastic methods to ''cool'' the beam. Pairs of quarter-wavelength directional-coupler loops are used to detect and kick the beam. The loops are copper plates which are flush with the upper and lower wall of a rectangular beam pipe. The plates, when surrounded by a properly sized pocket, form a 100-ohm transmission-line directional coupler. As the beam passes, a signal which gives position and time information, is induced in the plates. But, because the signal levels are low (<.5 picowatts per pair), a power combiner (usually several primary combiners feeding a secondary combiner) is used to combine the outputs of many loops. Subsequently, the combined signal is amplified, filtered and then fed into a divider, (that is, a combiner operating in reverse). The divider distributes the signal into a different set of loops which modify (kick) the beam's position. Since the loop couplers are arranged linearly, in arrays of various lengths, combiners also provide a convenient method of reducing the number of vacuum feedthroughs and preamplifiers and their related costs in performance and dollars. In this note we describe various stripline combiner systems that add the outputs of 4, 8, 16 or 32 loops.

Johnson, J.K.; Nemetz, R.

1985-05-01

 
 
 
 
421

Power combiners/dividers for loop pickup and kicker arrays for FNAL stochastic cooling rings  

International Nuclear Information System (INIS)

The anti-proton accumulator and debuncher at FNAL will use stochastic methods to ''cool'' the beam. Pairs of quarter-wavelength directional-coupler loops are used to detect and kick the beam. The loops are copper plates which are flush with the upper and lower wall of a rectangular beam pipe. The plates, when surrounded by a properly sized pocket, form a 100-ohm transmission-line directional coupler. As the beam passes, a signal which gives position and time information, is induced in the plates. But, because the signal levels are low (<.5 picowatts per pair), a power combiner (usually several primary combiners feeding a secondary combiner) is used to combine the outputs of many loops. Subsequently, the combined signal is amplified, filtered and then fed into a divider, (that is, a combiner operating in reverse). The divider distributes the signal into a different set of loops which modify (kick) the beam's position. Since the loop couplers are arranged linearly, in arrays of various lengths, combiners also provide a convenient method of reducing the number of vacuum feedthroughs and preamplifiers and their related costs in performance and dollars. In this note we describe various stripline combiner systems that add the outputs of 4, 8, 16 or 32 loops

1985-05-13

422

Nephrotoxicity and Oxidative Stress of Single Large Dose or Two Divided Doses of Gentamicin in Rats  

Directory of Open Access Journals (Sweden)

Full Text Available Gentamicin (GS is a potent antimicrobial exhibiting concentration dependent bacterial killing. A high dose of gentamicin (10 mg kg-1 is required to reach sufficient concentrations in specific fluids as cerebrospinal fluid and to be effective on antibiotics resistant bacteria as well as treatment of acute and dangerous illness. Using a rat model, the renal toxicity and oxidative stress of administering gentamicin (10 mg kg-1 daily for 7 days either in a single dose or divided into 2 doses was investigated. The safety of dose regimens was assessed through oxidant-antioxidant parameters as well as renal function tests. Typical renal damage and high oxidative stress were evident in the control group receiving 100 mg kg-1 gentamicin daily for 7 days. This was verified by high serum urea, uric acid, creatinine as well as increase in the levels of oxidative stress biomarkers as malondialdehyde, NO, total antioxidant capacity and decrease in reduced glutathione level. At any of the used regimen, 10 mg kg-1 gentamicin did not provide high compromise for renal functions nor significantly increased the oxidative stress and tissue damage. Based on microscopic lesions scores and biochemical analysis, there were no significant differences between single or two divided dosages of gentamicin at dose rate of 10 mg kg-1 day-1. Further studies are required for applications in other animals of human subjects.

Yasmin Tolba

2011-01-01

423

A divide-down RF source generation system for the Advanced Photon Source  

International Nuclear Information System (INIS)

A divide-down rf source system has been designed and built at Argonne National Laboratory to provide harmonically-related and phase-locked rf source signals between the APS 352-MHz storage ring and booster synchrotron rf systems and the 9.77-MHz and 117-MHz positron accumulator ring rf systems. The design provides rapid switching capability back to individual rf synthesizers for each one. The system also contains a digital bucket phase shifter for injection bucket selection. Input 352-MHz rf from a master synthesizer is supplied to a VXI-based ECL divider board which produces 117-MHz and 9.77-MHz square-wave outputs. These outputs are passed through low-pass filters to produce pure signals at the required fundamental frequencies. These signals, plus signals at the same frequencies from independent synthesizers, are fed to an interface chassis where source selection is made via local/remote control of coaxial relays. This chassis also produces buffered outputs at each frequency for monitoring and synchronization of ancillary equipment

1997-05-12

424

A study on how to divide and recodify the atomic energy act and its related regulations  

International Nuclear Information System (INIS)

As a part of big project named 'streamlining and optimization of nuclear safety regulatory system', this report focuses on how to divide and recodify the Atomic Energy Act and its related regulations. Follow the first chapter of preface, the second chapter shows the systemic problems of regulation of current AEA and out strategy to reform and re-systematize it. This report concludes that the regulations of the current AEA need to be divided in three parts, i.e. the presidential regulations of FWAAE, NNA and RPA and the ministerial regulation of AEA in two part, i.e. that of NNA and RPA. Then the problems of current regulations of AEA are pointed out and the alternative regulations of FWAAE and NNA are persented in the third and forth chapter respectively. In the fifth chapter RPA is persented. And finally the legal character of several nuclear safety standards is estimated. Concerning nuclear safety or technology standards, those issued by Minister of Science and Technology (MST) empowered by law or its regulation is obviously forceful as a law. But the standards made by KINS to meet the tasks entrusted to KINS by MST is only conditionally forceful as a law, that is, on the condition that law or regulation empowered the chief of KINS to make nuclear safety and/or technology standards

2003-01-01

425

Transition-state theory rate calculations with a recrossing-free moving dividing surface.  

Science.gov (United States)

Two different methods for transition-state theory (TST) rate calculations are presented that use the recently developed notions of the moving dividing surface and the associated moving separatrices: one is based on the flux-over-population approach and the other on the calculation of the reactive flux. The flux-over-population rate can be calculated in two ways by averaging the flux first over the noise and then over the initial conditions or vice versa. The former entails the calculation of reaction probabilities and is closely related to previous TST rate derivations. The latter results in an expression for the transmission factor as the noise average of a stochastic variable that is given explicitly as a function of the moving separatrices. Both the reactive-flux and flux-over-population methods suggest possible new ways of calculating approximate rates in anharmonic systems. In particular, numerical simulations of harmonic and anharmonic systems have been used to calculate reaction rates based on the reactive flux calculation using the fixed and moving dividing surfaces so as to illustrate the computational advantages of the latter. PMID:17935321

Bartsch, Thomas; Uzer, T; Moix, Jeremy M; Hernandez, Rigoberto

2008-01-17

426

The lateral mesodermal divide: an epigenetic model of the origin of paired fins.  

Science.gov (United States)

By examining development at the level of tissues and processes, rather than focusing on gene expression, we have formulated a general hypothesis to explain the dorso-ventral and anterior-posterior placement of paired appendage initiation sites in vertebrates. According to our model, the number and position of paired appendages are due to a commonality of embryonic tissue environments determined by the global interactions involving the two separated layers (somatic and visceral) of lateral plate mesoderm along the dorso-ventral and anterior-posterior axes of the embryo. We identify this distribution of developmental conditions, as modulated by the separation/contact of the two LPM layers and their interactions with somitic mesoderm, ectoderm, and endoderm as a dynamic developmental entity which we have termed the lateral mesodermal divide (LMD). Where the divide results in a certain tissue environment, fin bud initiation can occur. According to our hypothesis, the influence of the developing gut suppresses limb initiation along the midgut region and the ventral body wall owing to an "endodermal predominance." From an evolutionary perspective, the lack of gut regionalization in agnathans reflects the ancestral absence of these conditions, and the elaboration of the gut together with the concomitant changes to the LMD in the gnathostomes could have led to the origin of paired fins. PMID:24393466

Nuño de la Rosa, Laura; Müller, Gerd B; Metscher, Brian D

2014-01-01

427

Sector Dividing Method in Enroute Radar Airspace with Unbalanced Traffic Distribution  

Directory of Open Access Journals (Sweden)

Full Text Available In order to effectively meet the traffic demand changes in time and space, based on the multi-controller team, an adaptive airspace sector boundaries dividing method was proposed.First,the target airspace was processed with grid.Statistics of average distribution of the aircraft number for each grid, revised by adding the distribution coefficients of aircraft number which measure the (Air Traffic ControllerATC additional workload associating with coordinating, handover and resolve conflicts, alluding to each grid.the multi Huolang backpack method was used to group grids.This method ensure that the aircraft count does not exceed the monitor alert parameter(MAP.On this basis, rules which try to avoid increasing ATC workload was used to divide sector boundaries. Monitor alert parameters taking a value which is much bigger than median ensure that the the foundation sectors have more adaptability and security,as well controllers will not need additional training to adapt to changes in the sector range. The dynamic reaction logic control designed effective monitoring could effectively monitor MAP in plan time.Test results show that the higher the frequency of the dynamic response, the average number of aircraft in the sector of 15 minutes will be more closer MAP.

Zhijian Ye

2013-06-01

428

Computation of Private Key Based on Divide-By-Prime for Luc Cryptosystems  

Directory of Open Access Journals (Sweden)

Full Text Available Problem statement: One of the public key cryptosystem is Luc cryptosystems. This system used Lucas Function for encryption and decryption process. Lucas Function is a special form of second-order linear recurrence relation. An encyption process is used to encrypt an original message to ciphertext by using public key. A decryption process is the process to decrypt a ciphertext into original message using private key. The existing algorithm on computing private key computation involved some redundant computations. Approach: In this study, an efficient algorithm to compute private key for Luc cryptosystem is developed. The Extended Euclidean Algorithm will be enhanced by implementing Divide-By-Prime in its computations. The comparison is focused on the computation time by the existing and new algorithms. The more efficient algorithm means the better computation time. The shorter computation time the better algorithm. Results: A new algorithm shows better computation time. In all experiments, the computation time by new algorithm is always better than the existing algorithm. Conclusion: The new computation algorithm that based on Divide-By-Prime provided better efficiency of decryption process compared to the existing algorithm.

Nawara M.A. Makhzoum

2012-01-01

429

New Frontiers in the Digital Divide : Revisiting Policy for Digital Inclusion  

DEFF Research Database (Denmark)

In a new strategy for e-government, the Danish government set the goal that in 2015 all contacts between citizens and public authorities must be conducted electronically. In accordance with EUâ??s strategy for e-government every citizen ought to have equal access to public services, hence the question is: How to form a policy for digital inclusion where nobody is left behind? In continuation of the EU policy it seems reasonable to argue that the public authorities now has an obligation to â??dress upâ?? the citizens to serve themselves through the public e-services. Hence, policies and actions for digital inclusion becomes a central theme for the implementation of the new e-government strategy. Until now it has been voluntary whether or not citizens want to use ICT and a lot of especially senior citizens have chosen not to use the technology. However, senior citizens are not the only group affected of the e-government strategy. New frontiers in the digital divide are opening and a new group of excluded become visible: the youngsters. In this way, one of the leading Danish newspapers reports that young people lines up in town halls to get help to fill out forms, which are already available on the internet. The analysis in this paper is based on a multidisciplinary theoretical approach drawing on theories of the digital divide, theories of domestication of technology, and theories about the interplay between users and technology developed in the field of STS (Science, Technology and Society). In continuation of this theoretical framework the analysis is conducted as a mixed methods research where different kinds of knowledge are included. Hence, to analyze the Danish digital divide I draw on statistics developed by Statistics Denmark â?? the national agency for statistic â?? as well as a comprehensive qualitative study of senior citizensâ?? usage of ICT (Jæger, 2005). For the analysis of the policy I draw on a literature study of policy papers (Jæger & Löfgren 2010) as well as six qualitative interviews with key politicians â?? including the Minister of Science and Technology â?? and key civil servant.

Jæger, Birgit

430

Northwest outlet channels of Lake Agassiz, isostatic tilting and a migrating continental drainage divide, Saskatchewan, Canada  

Science.gov (United States)

Lake cores obtained from the northwest outlet of glacial Lake Agassiz in northwest Saskatchewan, Canada, provide a minimum date for the cessation of the flood from the northwest outlet, and a chronology for abandonment of mid-Holocene channels that presently straddle the Mackenzie and Churchill drainage divide. The stratigraphy of a vibracore taken from Long Lake consists of a lower pebble gravel fining to massive sand, silty-clay and then fibrous peat. Wood fragments from the base of the clay yielded an accelerator mass spectrometry (AMS) date of 9120 BP. Because the lake is scour in origin and is in the head of the spillway, the date is considered to be a minimum estimate for cessation of the flood from the northwest outlet at the beginning of the Emerson Phase. A vibracore taken at Haas Lake in an abandoned channel surrounded by muskeg with no influent streams, consists of 0.8 m of stratified, pebble gravel containing abundant shell and wood fragments, overlain by 1.62 m of gyttja with a sharp, conformable lower conta