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

Assessment of water-cooled breeder resistors for long pulse injection in acceleration power supply on positive-ion-based NBI system  

International Nuclear Information System (INIS)

Water-cooled breeder resistor, utilized in acceleration power supply on the positive-ion-based NBI system, has been designed to realize 100 s injections of intense neutral beams in JT-60 Super Advanced. The design is progressed with minimizing modification of existing electric parts. Existing water-cooled breeder resistors is composed of three water vessels connected in parallel, in each of which 150 resistors of 600 ? are immersed and connected in series. Although the manufacturing company requires entire replacement of water- cooled breeder, the careful assessment of thermal load allows only the replacement of the resistors inside the water vessel. The resistance of one resistors is required to be increased from 600 ? to 2.5 k?. The total resistance of the breeder is ?140 k? that includes the resistance of water. In the operation with the breeder of ?140 k?, stable production of 85 keV, 55 A D+ beams, allowing 2 MW of the designed injection power, was confirmed without instabilization of the acceleration power supply. This modification significantly reduces the cost and the manufacturing time. (author)

3

A Novel Voltage Divider Circuit  

Directory of Open Access Journals (Sweden)

Full Text Available A novel analog divider is described in this paper. The circuit enables the division of a dc voltage with another dc voltage. The constant of the division is dependent upon a third dc voltage and a pair of resistors. Employing a precision source for the third dc voltage and matched resistors, an acceptable level of accuracy can be obtained.

K. C. Selvam

2012-10-01

4

A Novel Voltage Divider Circuit  

OpenAIRE

A novel analog divider is described in this paper. The circuit enables the division of a dc voltage with another dc voltage. The constant of the division is dependent upon a third dc voltage and a pair of resistors. Employing a precision source for the third dc voltage and matched resistors, an acceptable level of accuracy can be obtained.

Selvam, K. C.; Latha, S.

2012-01-01

5

Breakdown voltage of metal-oxide resistors in liquid argon  

CERN Document Server

We characterized a sample of metal-oxide resistors and measured their breakdown voltage in liquid argon by applying high voltage (HV) pulses over a 3 second period to simulate the electric breakdown in a HV-divider chain. All resistors had higher breakdown voltages in liquid argon than their vendor ratings in air at room temperature. Failure modes range from full destruction to coating damage. In cases where breakdown was not catastrophic, subsequent breakdown voltages were lower in subsequent measuring runs. One resistor type withstands 131\\,kV pulses, the limit of the test setup.

Bagby, L F; James, C C; Jones, B J P; Jostlein, H; Lockwitz, S; Naples, D; Raaf, J L; Rameika, R; Schukraft, A; Strauss, T; Weber, M S; Wolbers, S A

2014-01-01

6

Experimental and Analytic Studies of an RF Load Resistor  

International Nuclear Information System (INIS)

The pulsed output of an 850-MHz klystron was directed into a load assembly containing a water-cooled, 50-ohm resistor. The load was systematically subjected to high peak-power pulses from the klystron. Several thin-film resistors were tested and exhibited various damage patterns for different combinations of peak microwave power (33 kW - 500 kW) and heat input. In order to better understand the phenomena observed, the electromagnetic field distribution inside the resistor housing was studied with WaveSim, a two-dimensional, finite-element scattering code. The conformal mesh of the program allowed accurate representations of the complex assembly geometry

7

High voltage load resistor array  

Science.gov (United States)

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

Uniform tiling with electrical resistors  

CERN Document Server

Electric resistances between two arbitrary nodes on any infinite lattice structure of resistor networks that is a periodic tiling of the space is obtained. Our general approach is based on the lattice Green's function of the Laplacian matrix associated with the network. We present several and non-trivial examples to show how efficient our method is. Deriving explicit resistance formulas it is shown that the Kagom\\'e, the diced and the decorated lattice can be mapped to the triangular and square lattice of resistors. Our work can be extended to random walk problem or electron dynamics in condensed matter physics.

Cserti, Jozsef; David, Gyula

2011-01-01

9

Remote Experiments in Resistor Measurement  

Directory of Open Access Journals (Sweden)

Full Text Available The paper describes blended learningapproach to teaching resistor measurement. It is basedon “Learning by Doing” paradigm: interacticesimulation, laboratory plants, real experimentsaccessed by Web Publishing Tools under LabVIEW.Studying and experimenting access is opened for 24hours a day, 7 days a week under Moodle bookingsystem.

Popescu Viorel

2009-10-01

10

Dual design resistor for high voltage conditioning and transmission lines  

Science.gov (United States)

A dual resistor for eliminating the requirement for two different value resistors. The dual resistor includes a conditioning resistor at a high resistance value and a run resistor at a low resistance value. The run resistor can travel inside the conditioning resistor. The run resistor is capable of being advanced by a drive assembly until an electrical path is completed through the run resistor thereby shorting out the conditioning resistor and allowing the lower resistance run resistor to take over as the current carrier.

Siggins, Timothy Lynn (Newport News, VA); Murray, Charles W. (Hayes, VA); Walker, Richard L. (Norfolk, VA)

2007-01-23

11

Dividing Fractions  

Science.gov (United States)

In this lesson students will explore the different methods available for dividing fractions through a student based investigation. The teacher will facilitate the discussion but the students will discover the different methods on their own or with a partner as they work through the different steps.

2012-10-17

12

Reliability growth of thin film resistors contact  

Directory of Open Access Journals (Sweden)

Full Text Available Necessity of resistive layer growth under the contact and in the contact zone of resistive element is shown in order to reduce peak values of current flow and power dissipation in the contact of thin film resistor, thereby to increase the resistor stability to parametric and catastrophic failures.

Lugin A. N.

2010-10-01

13

Resistance contact thin-film resistor  

Directory of Open Access Journals (Sweden)

Full Text Available The analytical model of the calculation of the contact resistance of the thin-film resistor is Offered. The Explored dependency of the contact resistance from wedge of the pickling. The Considered influence adhesive layer on warm-up stability of the resistor. They Are Received formulas of the calculation systematic and casual inaccuracy contributed by contact resistance.

Spirin V. G.

2008-10-01

14

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

15

Reliability growth of thin film resistors contact  

OpenAIRE

Necessity of resistive layer growth under the contact and in the contact zone of resistive element is shown in order to reduce peak values of current flow and power dissipation in the contact of thin film resistor, thereby to increase the resistor stability to parametric and catastrophic failures.

Lugin A. N.; Ozemsha M. M.

2010-01-01

16

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

17

CONDUCTION MECHANISMS IN THICK FILM RESISTORS  

OpenAIRE

The work reported here has focused on the influence of substrate dissolution during the high temperature firing on the electrical properties of ruthenium dioxide-lead borosilicate thick film resistors. A resistor 25 (mu)m thick that is fired for 10 minutes at 840(DEGREES)C will dissolve 4 (mu)m of the substrate surface. The presence of the alumina in the glass phase retards the growth of the resistor microstructure or chains of conducting particles by increasing the glass viscosity and slight...

Himelick, James Max

1980-01-01

18

Predicted effects on ground water of construction of Divide Cut section, Tennessee-Tombigbee Waterway, northeastern Mississippi, using a digital model  

Science.gov (United States)

The Tennessee-Tombigbee Waterway, connecting the Tennessee River in northeastern Mississippi with the Gulf of Mexico, is currently (1980) under construction. The Divide Section, the northernmost 39 miles of the Waterway, will consist, from north to south, of (1) a dredged channel, (2) the Divide Cut, and (3) an artifical lake impounded by the Bay Springs Dam. In all three , water will be at Tennessee River level. A three-dimensional digital model covering 3,273 square miles was constructed to simulate ground-water flow in the Gordo and Eutaw Formations and the Coffee Sand in the vicinity of the Divide Section. The model was calibrated to preconstruction water levels, then used to simulate the effects of stresses imposed by the construction of the Divide Section. The model indicates that the system stabilizes after major changes in conditions within a few months. The Divide Cut acts as a drain, lowering water levels as much as 55 feet. Drawdowns of 5 feet occur as much as 8 miles from the Cut. The 80-foot-high Bay Springs Dam raises ground-water levels by 5 feet as far as 6 miles from its impoundment. Drawdown is not likely to affect public water supplies significantly, but probably will adversely affect a relatively small number of private wells. (USGS)

McBride, Mark S.

1981-01-01

19

Suppressing Thermal Energy Drift In The LLNL Flash X-Ray Accelerator Using Linear Disk Resistor Stacks  

International Nuclear Information System (INIS)

This paper addresses thermal drift in sodium thiosulfate liquid resistors and their replacement with linear disk resistors from HVR Advanced Power Components. Sodium thiosulfate resistors in the FXR induction linear accelerator application have a temperature coefficient of ?1.8%/C. The FXR Marx banks send an 8kJ pulse through eight 524 cm3 liquid resistors at a repetition rate of up to 1 every 45 seconds. Every pulse increases the temperature of the solution by ?0.4 C which produces a 0.7% change in resistance. The typical cooling rate is ?0.4 C per minute which results in ?0.1% energy drop per pulse during continuous pulsed operations. A radiographic accelerator is extraordinarily sensitive to energy variations. Changes in beam energy produce movement in beam transport, changes in spot size, and large dose variations. If self-heating were the only problem, we could predict the increase in input voltage required to compensate for the energy loss. However, there are other variables that influence the temperature of the resistors such as focus magnet heating, changes in room temperature, changes in cooling water, where the cell is located, etc. Additionally not all of the resistors have equivalent cooling rates and as many as 32 resistors are driven from a single power source. The FXR accelerator group elected to replace the sodium thiosulfate resistors with HVR Linear Disk Resistors in a stack type configuration. With data limited for these resistorsh data limited for these resistors when used in oil and at low resistance values, a full characterization needed to be performed. High currents (up to 15kA), high voltages (up to 400kV), and Fast Rise times (<10ns) made a resistor choice difficult. Other solid resistors have been tried and had problems at the connection points and with the fact that the resistivity changed as they absorbed oil. The selected HVR resistors have the advantage of being manufactured with the oil impregnated in to them so this characteristic is minimized while still offering the desired low temperature coefficient of resistance compared to sodium thiosulfate. The characterization experiments and comparison with the sodium thiosulfate liquid resistors will be fully discussed and the final design described.

20

Suppressing Thermal Energy Drift In The LLNL Flash X-Ray Accelerator Using Linear Disk Resistor Stacks  

Energy Technology Data Exchange (ETDEWEB)

This paper addresses thermal drift in sodium thiosulfate liquid resistors and their replacement with linear disk resistors from HVR Advanced Power Components. Sodium thiosulfate resistors in the FXR induction linear accelerator application have a temperature coefficient of {approx}1.8%/C. The FXR Marx banks send an 8kJ pulse through eight 524 cm{sup 3} liquid resistors at a repetition rate of up to 1 every 45 seconds. Every pulse increases the temperature of the solution by {approx}0.4 C which produces a 0.7% change in resistance. The typical cooling rate is {approx}0.4 C per minute which results in {approx}0.1% energy drop per pulse during continuous pulsed operations. A radiographic accelerator is extraordinarily sensitive to energy variations. Changes in beam energy produce movement in beam transport, changes in spot size, and large dose variations. If self-heating were the only problem, we could predict the increase in input voltage required to compensate for the energy loss. However, there are other variables that influence the temperature of the resistors such as focus magnet heating, changes in room temperature, changes in cooling water, where the cell is located, etc. Additionally not all of the resistors have equivalent cooling rates and as many as 32 resistors are driven from a single power source. The FXR accelerator group elected to replace the sodium thiosulfate resistors with HVR Linear Disk Resistors in a stack type configuration. With data limited for these resistors when used in oil and at low resistance values, a full characterization needed to be performed. High currents (up to 15kA), high voltages (up to 400kV), and Fast Rise times (<10ns) made a resistor choice difficult. Other solid resistors have been tried and had problems at the connection points and with the fact that the resistivity changed as they absorbed oil. The selected HVR resistors have the advantage of being manufactured with the oil impregnated in to them so this characteristic is minimized while still offering the desired low temperature coefficient of resistance compared to sodium thiosulfate. The characterization experiments and comparison with the sodium thiosulfate liquid resistors will be fully discussed and the final design described.

Kreitzer, B R; Houck, T L; Luchterhand, O C

2011-07-19

21

Determination of cadmium in individual organs and divided shells of sea water clam by atomic absorption spectrometry with a carbon tube atomizer  

International Nuclear Information System (INIS)

Cadmium contents in individual organs and divided shells of sea water clam were estimated by atomic absorption with a carbon tube atomizer. After samples were digested with nitric acid, cadmium was separated from the interfering sample matrices by extracting it into diisobutyl ketone as diethyldithiocarbamate. By this method, 0.06 -- 0.75 ppb of cadmium was found in the divided shells. In the shellfish, cadmium was enriched to a very high extent in the kidney, to some degree in the organ of Keber. (author)

22

Charge pulse restorer for resistor feedback preamplifiers  

International Nuclear Information System (INIS)

A simple circuit for cancelling the main pole of traditional resistor feedback preamplifier output signals has been designed. The resultant waveform is a series of step functions equivalent to the output of a pulsed feedback preamplifier. The advantage of such a preamplifier output signal is that its quantized samples can directly be processed by certain digital signal processors. ((orig.))

23

Study of thin-film resistor resistance error  

Directory of Open Access Journals (Sweden)

Full Text Available A relationship between a thin-film resistor resistance error and mask misalignment with a substrate conductive layer at the second photolithography stage for a thin-film resistor design in which the resistive element does not overlap conductor pads is studied. The error value is at a maximum when the resistor aspect ratio is equal to 1.0.

Spirin V. G.

2009-10-01

24

Development of resistor assemblies at 14 UD pelletron accelerator facility BARC-TIFR, Mumbai  

International Nuclear Information System (INIS)

An important consideration in high voltage design of an electrostatic accelerator is the potential grading system used to divide the terminal potential equitably (or as required) across the column or tube electrode gaps. This is generally accomplished by tapping the electrode potentials from across a resistor-chain or from a series of corona gaps as in the Pelletron Accelerator. However, each potential grading system has its own set of advantages and disadvantages

25

Braking Resistor Scheme for Transient Stability Improvement  

Directory of Open Access Journals (Sweden)

Full Text Available One of the most important problems in power systems design is increasing the damping of the swing amplitude and also to increase the critical time in transient stability. One of the best techniques is to use resistor braking. However, their performance in power systems, duration of their activity and their place of installation are of great importance. In this paper by using of some of devices in power electronics and by precies modeling of the network and optimal controller is designed which leads as to our final objective. In fact resistor braking are effectively attract additive energy which is a result of disturbances and help us to improve the stability of overall system.

Saeed Abazari

2007-09-01

26

Characterization of feedback resistors for cryogenic applications  

Science.gov (United States)

Results are presented on the testing of feedback resistors selected for use in the transimpedance amplifiers (TIAs) in the Diffuse Infrared Background Experiment (DIRBE) to be flown on the NASA's Cosmic Background Explorer satellite planned for a launch in 1989. The resistors without encapsulation were found to be reliable as cryogenic circuit elements. Their resistance is sufficiently high (so that their Johnson noise does not dominate amplifier noise at the signal frequency), and they are sufficiently linear; no correction need to be made for signals up to 1.5 V, the 100,000 signal-to-noise level for the DIRBE, which covers most of the signals expected to be seen on the sky.

Lakew, B.; Moseley, S. H.; Silverberg, R. F.

1989-01-01

27

Studies of tantalum nitride thin film resistors  

International Nuclear Information System (INIS)

Backscattering of 2-MeV He ions was used to correlate the electrical properties of sputtered TaN/sub x/ thin-film resistors with their N content. The properties measured were sheet resistance, differential Seebeck potential (DSP), thermal coefficient of resistance (TCR), and stability. Resistivity and DSP are linearly dependent on N content for N/Ta ratios of 0.25 to 0.55. TCR decreases sharply below N/Ta = 0.35 and is relatively constant from 0.35 to 0.55. Stability is independent of N content. (DLC)

28

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

29

Variable thermal resistor based on self-powered Peltier effect  

International Nuclear Information System (INIS)

Heat flow through a thermoelectric material or device can be varied by an electrical resistor connected in parallel to it. This phenomenon is exploited to design a novel thermal component-variable thermal resistor. The theoretical background to this novel application is provided and an experimental result to demonstrate its feasibility is reported. (fast track communication)

30

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.)

31

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. PMID:24464243

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

32

Simulation of electromigration based on resistor networks  

Science.gov (United States)

A two-dimensional computer simulation of electromigration based on resistor networks is presented. The model utilizes a realistic grain structure generated by the Monte Carlo method and takes specific account of the local effects through which electromigration damage progresses. The dynamic evolution of the simulated thin film is governed by the local current and temperature distributions. The current distribution is calculated by superimposing a two-dimensional electrical network on the lattice whose nodes correspond to the particles in the lattice and the branches to interparticle bonds. The current distribution problem is solved by applying Kirchoff's rules on the resulting electrical network. The calculation of the temperature distribution in the lattice proceeds by discretizing the partial differential equation for heat conduction, with appropriate material parameters chosen for the lattice and its defects. The simulation was tested by applying it to common situations arising in experiments with real films. Specifically, the model successfully reproduces the expected grain size, linewidth and bamboo effects, the log-normal failure time distribution, and the relationship between current-density exponent and current density.

Patrinos, A. J.; Schwarz, J. A.

1994-06-01

33

Sensitive method for characterizing liquid helium cooled preamplifier feedback resistors  

Science.gov (United States)

It is pointed out that the simple and traditional method of measuring resistance using an electrometer is ineffective since it is limited to a narrow and nonrepresentative range of terminal voltages. The present investigation is concerned with a resistor measurement technique which was developed to select and calibrate the Transimpedance Mode Amplifier (TIA) load resistors on the Infrared Astronomical Satellite (IRAS) for the wide variety of time and voltage varying signals which will be processed during the flight. The developed method has great versatility and power, and makes it possible to measure the varied and complex responses of nonideal feedback resistors to IR photo-detector currents. When employed with a stable input coupling capacitor, and a narrow band RMS voltmeter, the five input waveforms thouroughly test and calibrate all the features of interest in a load resistor and its associated TIA circuitry.

Smeins, L. G.; Arentz, R. F.

1983-01-01

34

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

35

A resistor interpretation of general anisotropic cardiac tissue.  

Science.gov (United States)

This paper describes a spatial discretization scheme for partial differential equation systems that contain anisotropic diffusion. The discretization method uses unstructured finite volumes, or the boxes, that are formed as a secondary geometric structure from an underlying triangular mesh. We show how the discretization can be interpreted as a resistive circuit network, where each resistor is assigned at each edge of the triangular element. The resistor is computed as an anisotropy dependent geometric quantity of the local mesh structure. Finally, we show that under certain conditions, the discretization gives rise to negative resistors that can produce non-physical hyperpolarizations near depolarizing stimuli. We discuss how the proper choice of triangulation (anisotropic Delaunay triangulation) can ensure monotonicity (i.e. all resistors are positive). PMID:14739082

Shao, Hai; Sampson, Kevin J; Pormann, John B; Rose, Donald J; Henriquez, Craig S

2004-02-01

36

¿Agua dividida, agua compartida? Acuiferos transfronterizos en Sudamérica, una aproximación / Divided Water, Shared Water? An Approach to Cross-border Aquifers in South America  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish Este artículo aborda la política fronteriza del agua en Sudamérica, con una discusión específica sobre la frontera Colombia-Venezuela. Con una perspectiva comparativa, la autora aborda el impacto de los procesos políticos en la distribución y acceso al agua en regiones fronterizas. La autora señala [...] que la internacionalización del manejo del agua en zonas fronterizas debilita la participación pública debido al limitado conocimiento de la agenda ambiental de los macro esfuerzos regionales como la Comunidad Andina y sus instituciones. Los ríos o acuíferos compartidos son recursos ''invisibles'' para el común de los ciudadanos en Sudamérica, que pueden convertirse en fuente potencial de conflictos o de cooperación e integración regional. La cooperación es definitivamente necesaria en estos casos. Pocos esfuerzos se han registrado recientemente en Latinoamérica. Entre estos, destaca el programa Acuíferos Transfronterizos de las Américas (ISARM en Inglés), creado en 2002 por la UNESCO. Es particularmente importante poner atención en la falta de acuerdos trasnacionales sobre acuíferos transfronterizos en Sudamérica para compartir responsabilidades y toma de decisiones sobre el manejo de estas aguas. La autora señala el caso particular del acuífero transfronterizo Cúcuta-San Antonio sin un aparente manejo binacional entre Colombia y Venezuela. Abstract in english This article focuses on border water politics in South America with specific discussion of the Colombia-Venezuela Border. Through a comparative perspective, the author analyzes the impact of political decision-making on water access and distribution in border contexts. The author argues that the int [...] ernationalization of water management in these border regions weakens public participation due to limited public knowledge of the environmental agendas of regional organizations, such as the Andean Community and its institutions. Shared driver basins or aquifers are invisible resources for all citizens in South America which can be transformed into potential sources of conflict or cooperation and regional integration. Cooperation is definitely necessary in these cases. A few efforts have been noted recently in Latin America. Amongst them is one by conducted by UNESCO called ISARM (International Shared Aquifer Resource Management), created in 2002. It is particularly important to place attention on the lack of transnational agreements on South American water borders on the sharing of responsibilities, decisions and the management of transboundary waters. The author highlights the case of the Cúcuta-San Antonio aquifer between Colombia and Venezuela, which lacks clear bi-national management.

Carmen, Maganda.

2008-06-01

37

Formation of thin-film resistors on silicon substrates  

Science.gov (United States)

The formation of thin-film resistors by the ion implantation of a metallic conductive layer in the surface of a layer of phosphosilicate glass or borophosphosilicate glass which is deposited on a silicon substrate. The metallic conductive layer materials comprise one of the group consisting of tantalum, ruthenium, rhodium, platinum and chromium silicide. The resistor is formed and annealed prior to deposition of metal, e.g. aluminum, on the substrate.

Schnable, George L. (Montgomery County, PA); Wu, Chung P. (Hamilton Township, Mercer County, NJ)

1988-11-01

38

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

39

Free-standing silicon micro machined resistors from (110) substrate  

International Nuclear Information System (INIS)

A simple process to obtain silicon planes released from the substrate and provided with large area pads for ohmic contacts is described. Resistors 500 ?m long with a 40 ?m x 1 ?m cross section were obtained. Resistance measurements showed that the current flows in a reduced cross section, probably owing to the presence of a superficial depletion layer. Preliminary magnetoresistance measurements are presented. Reduction of the resistor cross section can be obtained by thermal oxidation

40

The great technological divide  

OpenAIRE

Whereas some hospitals and medical schools are introducing telemedicine networks and computer assisted learning, health clinics elsewhere do not even have the facilities to carry out a caesarean section. Ganapati Mudur sees a digital divide opening up in South Asia

Mudur, Ganapati

2004-01-01

41

Dividing Fractions by Fractions  

Science.gov (United States)

This site gives a description of how to divide fractions and gives a sample problem in which the denominator fraction is inverted, the numerators and denominators are multiplied, and the resulting fraction is simplified. It also includes the same problem solved by 'canceling' the fractions to simplify, and completing the process. There is also a game for students to practice their new skill of dividing and simplifying fractions.

2010-07-02

42

Anisotropic high temperature superconductors as variable resistors and switches  

Energy Technology Data Exchange (ETDEWEB)

Several anisotropic high temperature superconductors show critical current densities which are strongly dependent on the direction of an applied external magnetic field. The resistance of a sample can change by several orders of magnitude by applying a magnetic field. The potential for using the field dependent variable resistor or switch for applications in power systems is evaluated. Test results with small samples are presented. The requirements for large scale applications are outlined. The magnetic field triggering requirement, the frequency response of the device, use in 60 Hz ac circuits and heat transfer consideration are investigated. Several application examples are discussed. Use of variable resistor as a fault current limiter, as a switching element in rectifier circuitry and as an improved dump resistor for a superconducting magnet is presented.

Boenig, H.J.; Daugherty, M.A.; Fleshler, S.; Maley, M.P.; Mueller, F.M.; Prenger, F.C.; Coulter, J.Y.

1994-12-01

43

TI--CR--AL--O thin film resistors  

Science.gov (United States)

Thin films of Ti--Cr--Al--O are used as a resistor material. The films are rf sputter deposited from ceramic targets using a reactive working gas mixture of Ar and O.sub.2. Resistivity values from 10.sup.4 to 10.sup.10 Ohm-cm have been measured for Ti--Cr--Al--O film Ti--Cr--Al--O as a thin film resistor has been found to be thermodynamically stable, unlike other metal-oxide films. The Ti--Cr--Al--O film can be used as a vertical or lateral resistor, for example, as a layer beneath a field emission cathode in a flat panel display; or used to control surface emissivity, for example, as a coating on an insulating material such as vertical wall supports in flat panel displays.

Jankowski, Alan F. (Livermore, CA); Schmid, Anthony P. (Solana Beach, CA)

2000-01-01

44

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

45

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

46

A random resistor network model of voltage trimming  

International Nuclear Information System (INIS)

In industrial applications, the controlled adjustment (trimming) of resistive elements via the application of high voltage pulses is a promising technique, with several advantages with respect to more classical approaches such as the laser cutting method. The microscopic processes governing the response to high voltage pulses depend on the nature of the resistor and on the interaction with the local environment. Here we provide a theoretical statistical description of voltage discharge effects on disordered composites by considering random resistor network models with different properties and processes due to the voltage discharge. We compare standard percolation results with biased percolation effects and provide a tentative explanation of the different scenarios observed during trimming processes

47

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

48

Germanium as an integrated resistor material in RF MEMS switches  

Science.gov (United States)

This paper introduces the use of germanium as resistive material in RF MicroElectroMechanical (MEMS) devices. Integrated resistors are indeed highly required into RF MEMS switches, in order to prevent any RF signal leakage in the bias lines and also to be compatible with ICs. Germanium material presents strong advantages compared to others. It is widely used in microtechnologies, notably as an important semi-conductor in SiGe transistors as well as sacrificial or structural layers and also mask layer in various processes (Si micromachining especially). But it also presents a great electrical characteristic with a very high resistivity value. This property is particularly interesting for the elaboration of integrated resistors for RF components as it assures miniaturised resistors in total agreement with electromagnetic requirements. Its compatibility as resistive material in MEMS has been carried out. Its integration in the entire MEMS process has been fruitfully achieved and led to the successful demonstration and validation of integrated Ge resistors into serial RF MEMS variable capacitors, without any RF perturbations.

Grenier, K.; Bordas, C.; Pinaud, S.; Salvagnac, L.; Dubuc, D.

2007-05-01

49

Monitoring the digital divide  

International Nuclear Information System (INIS)

It is increasingly important to support the large numbers of scientists working in remote areas and having low-bandwidth access to the Internet. This will continue to be the case for years to come since there is evidence from PingER performance measurements that the, so-called, digital divide is not decreasing. In this work, we review the collaborative work of The Abdus Salam International Center for Theoretical Physics (ICTP) in Trieste - a leading organization promoting science dissemination in the developing world- and SLAC in Stanford, to monitor by PingER, Universities and Research Institutions all over the developing world following the recent 'Recommendations of Trieste' to help bridge the digital divide. As a result, PingER's deployment now covers the real-time monitoring of worldwide Internet performance and, in particular, West and Central Africa for the first time. We report on the results from the ICTP sites and quantitatively identify regions with poor performance, identify trends, discuss experiences and future work. (author)

50

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

Energy Technology Data Exchange (ETDEWEB)

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

51

Alternative power supply and dump resistor connections for similar, mutually coupled, superconducting coils  

International Nuclear Information System (INIS)

Alternative methods of connecting similar mutually coupled coils to their power supplies and dump resistors are investigated. The circuits are evaluated for both operating and fault conditions. The factors considered are the voltage to ground during a dump, short circuits, open circuits, quenches, and failure of the protection system to detect a quench. Of particular interest are the currents induced in coils that remain superconducting when one or more coils quench. The alternative connections include combined power supplies, individual dump resistors, combined resistors and series and parallel dump resistors. A new circuit that contains ''coupling'' resistors is proposed. The coupling resistors do not affect normal fast dumps but reduce the peak induced currents while also reducing the energy rating of the dump resistors. Another novel circuit, the series circuit with diodes, is discussed. The MFTF-B central-cell solenoids are used as an example

52

Alternative power supply and dump resistor connections for similar, mutally coupled, superconducting coils  

International Nuclear Information System (INIS)

Alternative methods of connecting similar mutually coupled coils to their power supplies and dump resistors are investigated. The circuits are evaluated for both operating and fault conditions. The factors considered are the voltage to ground during a dump, short circuits, open circuits, quenches, and failure of the protection system to detect a quench. Of particular interest are the currents induced in coils that remain superconducting when one or more coils quench. The alternative connections include combined power supplies, individual dump resistors, combined resistors and series and parallel dump resistors. A new circuit that contains coupling resistors is proposed. The coupling resistors do not affect normal fast dumps but reduce the peak induced currents while also reducing the energy rating of the dump resistors. Another novel circuit, the series circuit with diodes, is discussed. The MFTF-B central-cell solenoids are used as an example

53

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

54

Infinite Body Centered Cubic Network of Identical Resistors  

CERN Document Server

We express the equivalent resistance between the origin and any other lattice site in an infinite Body Centered Cubic (BCC) network consisting of identical resistors each of resistance R rationally in terms of known values and . The equivalent resistance is then calculated. Finally, for large separation between the origin and the lattice site two asymptotic formulas for the resistance are presented and some numerical results with analysis are given.

Asad, J H

2013-01-01

55

TaN resistor process development and integration.  

Energy Technology Data Exchange (ETDEWEB)

This paper describes the development and implementation of an integrated resistor process based on reactively sputtered tantalum nitride. Image reversal lithography was shown to be a superior method for liftoff patterning of these films. The results of a response surface DOE for the sputter deposition of the films are discussed. Several approaches to stabilization baking were examined and the advantages of the hot plate method are shown. In support of a new capability to produce special-purpose HBT-based Small-Scale Integrated Circuits (SSICs), we developed our existing TaN resistor process, designed for research prototyping, into one with greater maturity and robustness. Included in this work was the migration of our TaN deposition process from a research-oriented tool to a tool more suitable for production. Also included was implementation and optimization of a liftoff process for the sputtered TaN to avoid the complicating effects of subtractive etching over potentially sensitive surfaces. Finally, the method and conditions for stabilization baking of the resistors was experimentally determined to complete the full implementation of the resistor module. Much of the work to be described involves the migration between sputter deposition tools - from a Kurt J. Lesker CMS-18 to a Denton Discovery 550. Though they use nominally the same deposition technique (reactive sputtering of Ta with N{sup +} in a RF-excited Ar plasma), they differ substantially in their design and produce clearly different results in terms of resistivity, conformity of the film and the difference between as-deposited and stabilized films. We will describe the design of and results from the design of experiments (DOE)-based method of process optimization on the new tool and compare this to what had been used on the old tool.

Romero, Kathleen (LMATA, Albuquerque, NM); Martinez, Marino John; Clevenger, Jascinda; Austin, Franklin H., IV (, LMATA, Albuquerque, NM); Sullivan, Charles Thomas; Wolfley, Steven L.; Patrizi, Gary A.; Vigil, Pablita S. (LMATA, Albuquerque, NM); Grine, Alejandro J.

2010-05-01

56

Precision high voltage divider for the KATRIN experiment  

International Nuclear Information System (INIS)

The Karlsruhe Tritium Neutrino (KATRIN) experiment aims to determine the absolute mass of the electron antineutrino from a precise measurement of the tritium ?-spectrum near its endpoint at 18.6 keV with a sensitivity of 0.2 eV c-2. 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 the PTB are reported here. During the latter, uncertainties at the low ppm level have been deduced for the new divider, thus qualifying it for the precision measurements of the KATRIN experiment.

57

Characterization measurements of the wideband infrared scene projector resistor array  

Science.gov (United States)

Kinetic energy weapon (KEW) programs under the Ballistic Missile Defense Office (BMDO) need high fidelity, fast framing infrared (IR) imaging seekers. As imaging sensors have matured to support BMDO, the complexity of functions assigned to the KEW weapon systems has amplified the necessity for robust hardware-in-the-loop (HWIL) simulation facilities to reduce program risk. Tactical weapon systems are also turning to imaging focal plane array (FPA) seekers. They too require more sophisticated HWIL testing. The IR projector, an integral component of a HWIL simulation, must reproduce the real world with enough fidelity that the unit-under-tests's (UUT) software will respond to the projected scenario of images as though it were viewing the real world. The MOSFET resistor array IR scene projector shows great promise in cryogenic vacuum chamber as well as room temperature testing. Under the wideband infrared scene projector (WISP) program, an enhanced version of the resistor array is currently under development. When the WISP system is delivered, the projector will consist of a 512 by 512 baseline array with the center 128 by 128 resistors having a higher output capability. For the development stage of the program, 512 by 512 prototype baseline and 128 by 128 prototype high dynamic range (HDR) arrays have been fabricated separately. Characterization measurements to include: spectral output, dynamic range capability, apparent temperature, rise time, fall time, cross talk, and current consumption have been accomplished on the prototype baseline and HDR arrays at the Kinetic Kill Vehicle Hardware-in-the-Loop Simulator (KHILS) Facility and the Guided Weapons Evaluation Facility (GWEF). Results from the measurements show the HDR array dynamic range is an order of magnitude greater than its predecessor. Other parameters such as droop, rise time, etc., either meet or are close to meeting system specifications. The final design of the arrays is currently in progress based on these results.

Jones, Lawrence E.; Olson, Eric M.; Goldsmith, George C., II

1996-06-01

58

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

59

An automated resistor network to inspect the linearity of resistance-thermometry measurements  

International Nuclear Information System (INIS)

This note describes a resistor network that enables automated linearity checks of resistance-thermometry measurements. The network is made in such a manner that the voltages across any number of resistors in a resistor series are read to get separate four-terminal values interrelated by the formula for the series connection. Linearity tests of resistance bridges show that the network can resolve deviations from linearity down to ±20 ?? for resistance measurements from 32 to 284 ?. (technical design note)

60

Gentilly 2 divider plate replacement  

International Nuclear Information System (INIS)

The steam generators at the Gentilly 2 Nuclear Plant in operation since 1983 were built with primary divider plates of a bolted panel configuration. During a routine outage inspection, it was noted that two bolts had dislodged from the divider and were located lying in the primary head. Subsequent inspections revealed erosion damage to a substantial number of divider plate bolts and to a lesser extent, to the divider plate itself. After further inspection and repair the units were returned to operation, however, it was determined that a permanent replacement of the primary divider plates was going to be necessary. After evaluation of various options, it was decided that the panel type dividers would be replaced with a single piece floating design. The divider itself was to be of a one piece all-welded arrangement to be constructed from individual panels to be brought in through the manways. In view of the strength limitations of the bolted attachment of the upper seat bar to the tubesheet, a new welded seat bar was provided. To counteract erosion concerns, the new divider is fitted with erosion resistant inserts or weld buildup and with improved sealing features in order to minimize leakage and erosion. At an advanced stage in the design and manufacture of the components, the issue of divider strength during LOCA conditions came into focus. Analysis was performed to determine the strength and/or failure characteristics of the divider to a variety of small and large LOCA conditions. The paper describes the diagnosis of the original divider plates and the design, manufacture, field mobilization, installation and subsequent operation of the replacement divider plates. (author)

61

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

62

An optimized resistor pattern for temperature gradient control in microfluidics  

International Nuclear Information System (INIS)

In this paper, we demonstrate the possibility of generating high-temperature gradients with a linear temperature profile when heating is provided in situ. Thanks to improved optimization algorithms, the shape of resistors, which constitute the heating source, is optimized by applying the genetic algorithm NSGA-II (acronym for the non-dominated sorting genetic algorithm) (Deb et al 2002 IEEE Trans. Evol. Comput. 6 2). Experimental validation of the linear temperature profile within the cavity is carried out using a thermally sensitive fluorophore, called Rhodamine B (Ross et al 2001 Anal. Chem. 73 4117–23, Erickson et al 2003 Lab Chip 3 141–9). The high level of agreement obtained between experimental and numerical results serves to validate the accuracy of this method for generating highly controlled temperature profiles. In the field of actuation, such a device is of potential interest since it allows for controlling bubbles or droplets moving by means of thermocapillary effects (Baroud et al 2007 Phys. Rev. E 75 046302). Digital microfluidics is a critical area in the field of microfluidics (Dreyfus et al 2003 Phys. Rev. Lett. 90 14) as well as in the so-called lab-on-a-chip technology. Through an example, the large application potential of such a technique is demonstrated, which entails handling a single bubble driven along a cavity using simple and tunable embedded resistors

63

Investigation about decoupling capacitors of PMT voltage divider effects on neutron-gamma discrimination  

Science.gov (United States)

Scintillators are almost used in any nuclear laboratory. These detectors combine of scintillation materials, PMT and a voltage divider. Voltage dividers are different in resistive ladder design. But the effect of decoupling capacitors and damping resistors haven't discussed yet. In this paper at first a good equilibrium circuit designed for PMT, and it was used for investigating about capacitors and resistors in much manner. Results show that decoupling capacitors have great effect on PMT output pulses. In this research, it was tried to investigate the effect of Capacitor's value and places on PMT voltage divider in Neutron-Gamma discrimination capability. Therefore, the voltage divider circuit for R329-02 Hamamatsu PMT was made and Zero Cross method used for neutron-gamma discrimination. The neutron source was a 20Ci Am-Be. Anode and Dynode pulses and discrimination spectrum were saved. The results showed that the pulse height and discrimination quality change with the value and setting of capacitors.

Divani, Nazila; Bayat, Esmail; Firoozabadi, Mohammad M.

2014-11-01

64

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

65

Applications of the superconducting lossless resistor in electric power systems  

International Nuclear Information System (INIS)

The main features and some very useful applications of the superconducting lossless resistor (LLR) in electric power systems are introduced in this paper. According our opinion, there are two different kinds of LLR, i.e., the time-variant LLR (Tv-LLR) and the time-invariant LLR (Ti-LLR). First, Tv-LLR is well suited for developing new type of the fault-current limiter (FCL) since it has no heat energy dissipated from its superconducting element during current-limiting process. Second, it may be used to produce the high voltage circuit breaker with current limiting ability. While Ti-LLR may be used to manufacture a new type of the superconducting transformer, with compact volume, lightweight and with continuously regulated turn-ratio (so it familiarized as time-variable transformer, TVT)

66

Single-photon avalanche photodiodes with integrated quenching resistor  

International Nuclear Information System (INIS)

In this paper we present the results of the first electrical and optical characterization performed on STMicroelectronics new photosensor technology based on silicon single-photon avalanche photodiodes (SPAD). On the prospective of the design and the manufacturing of large-area silicon photomultipliers to be used as photodetectors for nuclear medicine imaging applications, we have modified our previous SPAD technology by means of the integration of a high-value quenching resistor to the photodiode. Moreover, an appropriate antireflective coating layer and the reduction of the quasi-neutral region thickness above the thin junction depletion layer have been introduced in the process flow of the device to enhance its spectral response in blue and near ultraviolet wavelength ranges. High gain, low leakage currents, low dark noise, very good quantum detection efficiency in blue-near UV ranges and a good linearity of the photodiode response to the incident luminous flux are the main characterization results

67

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.)

68

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

69

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

70

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

71

Superconducting-coil--resistor circuit with electric field quadratic in the current  

CERN Document Server

It is shown for the first time that the observed [Phys. Lett. A 162 (1992) 105] potential difference Phi_t between the resistor and the screen surrounding the circuit is caused by polarization of the resistor because of the kinetic energy of the electrons of the superconducting coil. The proportionality of Phi_t to the square of the current and to the length of the superconducting wire is explained. It is pointed out that measuring Phi_t makes it possible to determine the Fermi quasimomentum of the electrons of a metal resistor.

Poklonski, N A; 10.1134/1.1261987

2010-01-01

72

A random access memory immune to single event upset using a T-Resistor  

Science.gov (United States)

In a random access memory cell, a resistance ''T'' decoupling network in each leg of the cell reduces random errors caused by the interaction of energetic ions with the semiconductor material forming the cell. The cell comprises two parallel legs each containing a series pair of complementary MOS transistors having a common gate connected to the node between the transistors of the opposite leg. The decoupling network in each leg is formed by a series pair of resistors between the transistors together with a third resistor interconnecting the junction between the pair of resistors and the gate of the transistor pair forming the opposite leg of the cell. 4 figs.

Ochoa, A. Jr.

1987-10-28

73

Random access memory immune to single event upset using a T-resistor  

Science.gov (United States)

In a random access memory cell, a resistance "T" decoupling network in each leg of the cell reduces random errors caused by the interaction of energetic ions with the semiconductor material forming the cell. The cell comprises two parallel legs each containing a series pair of complementary MOS transistors having a common gate connected to the node between the transistors of the opposite leg. The decoupling network in each leg is formed by a series pair of resistors between the transistors together with a third resistor interconnecting the junction between the pair of resistors and the gate of the transistor pair forming the opposite leg of the cell.

Ochoa, Jr., Agustin (Vista, CA)

1989-01-01

74

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

75

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

International Nuclear Information System (INIS)

There is a need to characterize and apply advanced materials to improve the performance of components used in pulse power systems. One area of 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 in improved homogeneity, making the material suitable for use as a non-inductive high energy resistor. This paper describes characterization of the material's physical and electrical properties and relates them to improvements in low-inductance, high temperature, high power density and high energy density resistors. The bulk resistor approach offers high reliability through better mechanical properties and simplicity of construction

76

Method of calculation of thin-film resistor electrode’s impedance  

Directory of Open Access Journals (Sweden)

Full Text Available The physical and mathematical models of electrode impedance for the thin-film resistors of rectangular and interdigital shapes are presented in this work. The impact of electrode impedance on the manufacturing and temperature errors is estimated.

Spirin V. G.

2009-11-01

77

High-ohmic low-noise resistor for spectrometers with cooled semiconductor detectors  

International Nuclear Information System (INIS)

BackgroUnd noise and energy resolution of a new type of resistors, designed to be used as a resistance in a feedback circuit of an X-ray spectrometer preamplifier are studied. The resistors are manufactured using the method of photolithography from high-resistance films, formed on the surface of lead-silicate glasses, as a result of redox processes during heat treatment in hydrogen atmosphere. Energy resolution of the spectrometer is measured on the line 55FeKX(Mn) with the energy 5.8 keV. The conclusion is made, that the level of background noises in the resistors studied is approximately 4 times lower the level of noises in the KVM type resistors, which are commercially produced in industry

78

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

79

Information Societies and Digital Divides  

CERN Document Server

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

80

An Investigation of the Relationship between Resistance and Thickness of Deposited Nickel Thin Film Resistors  

Directory of Open Access Journals (Sweden)

Full Text Available The main purpose of this study is finding the relationship between resistance and thickness of deposited Nickel Thin Film Resistors. It was found that the Sheet Resistance, Rs, is inversely proportional to the thickness of the film on the substrate. It was also observed that when the film thickness is greater than 50 nm, films behave like ordinary resistors. In other words in bulk, films obey Ohm’s law if other physical quantities remain constant.

Ericam R.R. Mucunguzi-Rugwebe

2013-09-01

81

Chopper Controlled Resistors in VSC-HVDC Transmission for WPP with Full-scale Converters  

OpenAIRE

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, Sanjay Kumar; Teodorescu, Remus; Rodriguez, Pedro; Kjær, P. C.; Christensen, P. W.

2009-01-01

82

Sensitivity enhancement of polysilicon piezo-resistive pressure sensors with phosphorous diffused resistors  

International Nuclear Information System (INIS)

It is generally accepted that the piezo-resistive coefficient in single crystal silicon is higher when P-type impurities such as boron are used for doping the resistors. In this paper we demonstrate that the sensitivity of polycrystalline silicon piezo-resistive pressure sensors can be enhanced considerably when phosphorus diffusion source is used instead of boron dopant for realizing the piezo-resistors. Pressure sensors have been designed and fabricated with the polycrystalline piezo-resistors connected in the form of a Wheatstone bridge and laid out on thermal oxide grown on membranes obtained with a Silicon On Insulator (SOI) approach. The SOI wafers required for this purpose have been realized in-house by Silicon Fusion Bonding (SFB) and etch back technique in our laboratory. This approach provides excellent isolation between the resistors and enables zero temperature coefficient of the polysilicon resistor. The results obtained in our laboratory have clearly demonstrated that by optimizing the phosphorus diffusion temperature and duration, it is possible to achieve sensitivities in excess of 20mV /Bar for bridge input voltage of 10V, with linearity within 1% over a differential pressure range up to 10Bar (10 6Pascal), and burst pressure in excess of 50 Bar as compared to the 10mV /Bar sensitivity obtained with boron doped polysilicon piezo-resistors. This enhancement is attributed to grain boundary passivation by phosphorous atoms by phosphorous atoms

83

Transducer for a discrete helium level indicator on the base of carbon resistor  

International Nuclear Information System (INIS)

An indicator of a liquid helium level is described. The transducer of the indicator is made of a carbon resistor used usually as a temperature monitor. The influence of the transducer manufacturing process and measurement conditions on sensitivity and heat release in liquid helium is investigated. The resistors with the 0.1-1 kOhm resistance at the 300 K temperature and the moninal power of 0.125 and 0.25 W are used. The best results are obtained with the 1 kOhm and 0.25 W resistors. The change in signal taken from the transducer, is upto 100% for the vapor- liquid boundary transition at heat release in liquid, Wsub(l)=49 mW and upto 60% at Wsub(l)=1.6 mW. The accuracy of the level determination is <= 0.2 cm

84

The first measurements on SiPMs with bulk integrated quench resistors  

Energy Technology Data Exchange (ETDEWEB)

High ohmic polysilicon which is used as quench resistor in conventional Silicon photomultipliers (SiPMs) turns out to be an absorber for light and is one of the most cost and yield driving technological issues. The silicon photomultiplier is becoming a very good candidate for the replacement of conventional photomultiplier tubes and thus the development of these devices is very striking. We have proposed a new detector concept which has the quench resistor integrated into the silicon bulk avoiding polysilicon resistors. The quenching mechanism has been demonstrated in a proof of principle production performed in house. The first prototypes have been fabricated (second production run) and allowed testing of the device performance. The results from the first measurements will be presented. Based on these results the inherent advantages and drawbacks compared to standard SiPMs will be discussed.

Ninkovic, Jelena, E-mail: ninkovic@mppmu.mpg.d [Max-Planck-Institut fuer Physik, Foehringer Ring 6, D-80805 Munich (Germany); Max-Planck-Institut Halbleiterlabor, Otto-Hahn-Ring 6, D-81739 Munich (Germany); Andricek, Ladislav; Jendrisyk, Christian; Liemann, Gerhard [Max-Planck-Institut fuer Physik, Foehringer Ring 6, D-80805 Munich (Germany); Max-Planck-Institut Halbleiterlabor, Otto-Hahn-Ring 6, D-81739 Munich (Germany); Lutz, Gerhard [PNSensor GmbH, Roemerstr. 28, D-80803 Munich (Germany); Moser, Hans-Guenther; Richter, Rainer [Max-Planck-Institut fuer Physik, Foehringer Ring 6, D-80805 Munich (Germany); Max-Planck-Institut Halbleiterlabor, Otto-Hahn-Ring 6, D-81739 Munich (Germany); Schopper, Florian [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Max-Planck-Institut Halbleiterlabor, Otto-Hahn-Ring 6, D-81739 Munich (Germany)

2011-02-01

85

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)

86

A Biased Resistor Network Model for Electromigration Phenomena in Metallic Lines  

CERN Document Server

Electromigration phenomena in metallic lines are studied by using a biased resistor network model. The void formation induced by the electron wind is simulated by a stochastic process of resistor breaking, while the growth of mechanical stress inside the line is described by an antagonist process of recovery of the broken resistors. The model accounts for the existence of temperature gradients due to current crowding and Joule heating. Alloying effects are also included. Monte Carlo simulations enable us to study within a unified theoretical framework a variety of relevant features of electromigration phenomena. The predictions of the model are in excellent agreement with the experiments and in particular with the degradation towards electrical breakdown of stressed Al-Cu thin metallic lines. Detailed investigations refer to the damage pattern, the distribution of the times to failure (TTFs), the generalized Black's law, the time evolution of the resistance, including early-stage change due to alloying effect...

Pennetta, C; Reggiani, L; Fantini, F; De Munari, I; Scorzoni, A

2004-01-01

87

A fully integrated, monolithic, cryogenic charge sensitive preamplifier using N-channel JFETs and polysilicon resistors  

International Nuclear Information System (INIS)

In this paper, an integrated charge preamplifier to be used with small (10--30 mm2) Si(Li) and Ge(Li) X-ray detectors is described. The preamplifier is designed to operate at cryogenic temperatures (?100 K to 160 K) for the best performance. An N-channel JFET process technology for integrated charge sensitive preamplifiers has been developed. The process integrates multiple pinch-off voltage JFETs fabricated in an n-type epitaxial layer on a low resistivity p-type substrate. The process also incorporates polysilicon resistors integrated on the same die as the JFETs. The optimized polysilicon resistors exhibit 1/f noise nearly as good as metal film resistors at the same current. Results for integrated amplifier are discussed

88

Experimental study on the role of a resistor in the filter of Hall thrusters  

Science.gov (United States)

A filter is a mainly component applied to reduce the discharge current low frequency oscillation in the range of 10-100 kHz. The only form of the filter in actual use involves RLC networks, whose design originates from the 1970s, but even now, researchers are unaware of the actual primary motivations for the resistor's presence [S. Barral et al., AIAA Paper 2008-4632, 2008]. Therefore, the role of the resistor in the filter is experimentally studied and discussed through the analysis of control system and electric circuit theory. Experimental results and analysis indicate that the presence of a resistor makes the filter having the phase compensation function. The proper phase-angle and amplitude provided by the filter would increase or decrease the ion mobility and be helpful to balance the ion production in the discharge channel and then to decrease the fluctuation of the plasma density and lower the low frequency oscillation.

Liqiu, Wei; Chunsheng, Wang; Zhongxi, Ning; Weiwei, Liu; ChaoHai, Zhang; Daren, Yu

2011-06-01

89

Process for producing Ti-Cr-Al-O thin film resistors  

Science.gov (United States)

Thin films of Ti-Cr-Al-O are used as a resistor material. The films are rf sputter deposited from ceramic targets using a reactive working gas mixture of Ar and O.sub.2. Resistivity values from 10.sup.4 to 10.sup.10 Ohm-cm have been measured for Ti-Cr-Al-O film Ti-Cr-Al-O as a thin film resistor has been found to be thermodynamically stable, unlike other metal-oxide films. The Ti-Cr-Al-O film can be used as a vertical or lateral resistor, for example, as a layer beneath a field emission cathode in a flat panel display; or used to control surface emissivity, for example, as a coating on an insulating material such as vertical wall supports in flat panel displays.

Jankowski, Alan F. (Livermore, CA); Schmid, Anthony P. (Solana Beach, CA)

2001-01-01

90

Crossroads - Bridging the Digital Divide  

Directory of Open Access Journals (Sweden)

Full Text Available It’s so good to be in Cambridge, it feels almost like home. Let me start by stating that in the past year ITMB, a successful map publisher in British Columbia, Canada published more paper map titles than at any time in their history. Similarly, the U.S. Geological Survey (USGS recently announced that they have ceased producing paper from their aerial photography archive and will only produce digital copies. I believe that both of these facts speak to the future of maps and digital data. It means there will be paper maps well into the future and there will be an increasing array of digital data - some of it reformatted, as in the USGS case, and most of it will be born digital. When asked to speak about GIS and its role in libraries I often find myself in a conundrum - am I here to slay the dragon, or to pet the dragon. The role of technology in libraries is not one that has been embraced by everyone, and often the technology itself seems to have been force-fed upon us. The library profession is not one that has historically been a proponent of change and the very nature of GIS is change. In one sense, we have been given the choice of becoming paper museums or, at the very least, making GIS technology available in our collections. Today, I would like to review the many ways that GIS is, or will, affect our collections. I will divide the presentation into a general overview of GIS in libraries, how it affects our acquisitions or collection development policies, its effect on cataloging, on reference services, staffing, and our web services. Then I will shift the focus a little and discuss the current situation at the Harvard Map Collection, the future role of legacy collections, and a look to the future.

David Cobb

2005-03-01

91

Demonstration of a silicon photomultiplier with bulk integrated quenching resistors on epitaxial silicon  

International Nuclear Information System (INIS)

In this paper we present the experimental results of a silicon photomultiplier (SiPM) with bulk integrated quenching resistors on epitaxial silicon. Compared with existing SiPM with polysilicon quenching resistors on the surface or with MRS structure, it has potential advantages of high photon detection efficiency (PDE) while retaining a large micro-cell density and the fabrication process is also simplified. The SiPM with the micro-cell density up to 104/mm2 and the PDE up to 25.6% is demonstrated. The characteristics of dark count rate, single photon detection capability, gain, optical crosstalk and PDE have been investigated and discussed.

92

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

International Nuclear Information System (INIS)

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, new, conductive, bulk ceramic material has a controlled microstructure, which results in improved homogeneity, making the material suitable for use as a non-inductive, high energy resistor

93

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

Science.gov (United States)

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

94

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

95

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

96

Noisy random resistor networks: renormalized field theory for the multifractal moments of the current distribution  

OpenAIRE

We study the multifractal moments of the current distribution in randomly diluted resistor networks near the percolation treshold. When an external current is applied between to terminals $x$ and $x^\\prime$ of the network, the $l$th multifractal moment scales as $M_I^{(l)} (x, x^\\prime) \\sim | x - x^\\prime |^{\\psi_l /\

Stenull, Olaf; Janssen, Hans-karl

2000-01-01

97

Ni-Cr thin film resistor fabrication for GaAs monolithic microwave integrated circuits  

International Nuclear Information System (INIS)

Different Ni-Cr alloys were sputter-deposited on silicon nitride-coated GaAs substrates and covered with a spin-coated polyimide layer to develop thin film metal resistors for GaAs monolithic microwave integrated circuits (MMICs). The contact to the resistors was made through vias in the polyimide layer by sputter-deposited Ti/Au interconnect metal. The variation of contact resistance, sheet resistance (R S) and temperature coefficient of resistance (TCR) of the Ni-Cr resistors with fabrication process parameters such as polyimide curing thermal cycles and surface treatment given to the wafer prior to interconnect metal deposition has been studied. The Ni-Cr thin film resistors exhibited lower R S and higher TCR compared to the as-deposited Ni-Cr film that was not subjected to thermal cycles involved in the MMIC fabrication process. The change in resistivity and TCR values of Ni-Cr films during the MMIC fabrication process was found to be dependent on the Ni-Cr alloy composition

98

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

99

Social Welfare Implications of the Digital Divide  

Science.gov (United States)

The Internet plays a critical role in informing individuals about society, politics, business, and the environment. So much so that it has been said that the digital divide makes the segment of society on the ''right side'' of the divide (the digitally endowed group) better off and that on the ''wrong side'' (the digitally challenged group) worse…

Kim, Eunjin; Lee, Byungtae; Menon, Nirup M.

2009-01-01

100

Depth of interaction detection with enhanced position-sensitive proportional resistor network  

International Nuclear Information System (INIS)

A new method of determining the depth of interaction of ?-rays in thick inorganic scintillation crystals was tested experimentally. The method uses the strong correlation between the width of the scintillation light distribution within large continuous crystals and the ?-ray's interaction depth. This behavior was successfully reproduced by a theoretical model distribution based on the inverse square law. For the determination of the distribution's width, its standard deviation ? is computed using an enhanced position-sensitive proportional resistor network which is often used in ?-ray-imaging devices. Minor changes of this known resistor network allow the analog and real-time determination of the light distribution's 2nd moment without impairing the measurement of the energy and centroid. First experimental results are presented that confirm that the described method works correctly. Since only some cheap electronic components, but no additional detectors or crystals are required, the main advantage of this method is its low cost

101

Conductivity of a square-lattice bond-mixed resistor network  

International Nuclear Information System (INIS)

Within a real-space renormalization-group framework based on self-dual clusters, the conductivity of a square-lattice quenched bond-random resistor network is calculated, the conductance on each bond being g1 or g2 with probabilities (1-p) and p respectively. The group recovers several already known exact results (including slopes), and is consequently believed to be numerically quite reliable for almost all values of p, and all ratios g1/g2 (in particular, g1=0 and g1=infinite with finite g2 respectively correspond to the insulator-resitor and superconductor-resistor mixtures). In addition to that, an heuristic analytic expression is proposed for the conductivity which is believed to be a quite satisfactory approximation everywhere not too close to the percolation point. (Author)

102

SiMPl - High efficient silicon photomultipliers with integrated bulk resistor  

International Nuclear Information System (INIS)

Silicon photomultipliers (SiPM) are avalanche photodetectors which tend to replace conventional photomultiplier tubes in many application areas where detectors with high photon detection efficiency (PDE) are in the focus of interest. For Geiger mode operation high ohmic polysilicon is needed as quench resistor. On the one hand this forms a barrier for incident light, thus decreasing the PDE, which is a crucial point at low light levels. On the other hand it's also the most cost driving technological issue in fabrication. We present a novel design for a high efficient SiPM with the quench resistors integrated into the silicon bulk. Therefore obstacles for light like metal lines or contacts within the active area can be omitted and the fill factor of the device is only limited by the gaps necessary for optical crosstalk suppression. First results of this novel light detector are presented.

103

Photovoltaic spatial solitons affected by a resistor in the external circuit  

Science.gov (United States)

We have found that the FWHM of one-dimensional photovoltaic spatial soliton is modified by the space-charge field in the crystal, which can be controlled by a resistor in the external circuit. In this case, the photovoltaic contribution of a background beam is taken into account. In a crystal with a positive perturbation of refractive index, the FWHM of dark soliton decreases with the resistance of the resistor, while the FWHM of bright soliton increases with the resistance. Furthermore, when R (the ratio of the effective Glass constant of a signal beam over a background beam) is higher than 1, we can switch a dark soliton to a bright soliton by decreasing the resistance or vice versa. During such process, both the wavelengths and the intensities of the signal beam and the background beam are kept unchanged.

Wang, Xiao Sheng; She, Wei Long

2002-09-01

104

Nanoporous carbon tunable resistor/transistor and methods of production thereof  

Science.gov (United States)

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

105

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

OpenAIRE

The electrochemical and microstructural properties of carbon film electrodes made from carbon film electrical resistors of 1.5, 15, 140 [Omega] and 2.0 k[Omega] 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 inve...

Gouveia-caridade, Carla; Soares, David M.; Liess, Hans-dieter; Brett, Christopher M. A.

2008-01-01

106

Analysis of Regulated PV Fed Switched Reluctance Motor Drives Using Repression Resistor Converter  

Directory of Open Access Journals (Sweden)

Full Text Available The performance of the four phases SRM is investigated especially driven by standalone PV fed module with Repression Resistor converter. Inorder to perform the good working condition of motor, the basic behavior of SRM should be researched. Because of abundant solar energy sources the application is introduced in high speed drives such as SRM in this paper. The results also compared with SRM driven by DC source offers superior performance in simulation analysis.

S.Sujitha

2014-07-01

107

A study of cross-bridge kelvin resistor structures for reliable measurement of low contact resistances  

OpenAIRE

The parasitic factors that strongly influence the measurement accuracy of Cross-Bridge Kelvin Resistor (CBKR) structures for low specific contact resistances (?c) have been extensively discussed during last few decades and the minimum of the ?c value, which could be accurately extracted, was estimated. We fabricated a set of various metal-to-metal CBKR structures with different geometries, i.e., shapes and dimensions, to confirm this limit experimentally. As a result, a model was developed...

Stavitski, N.; Klootwijk, J. H.; Zeijl, H. W.; Kovalgin, A. Y.; Wolters, R. A. M.

2008-01-01

108

Maximum Bandwidth Enhancement of Current Mirror using Series-Resistor and Dynamic Body Bias Technique  

Directory of Open Access Journals (Sweden)

Full Text Available This paper introduces a new approach for enhancing the bandwidth of a low voltage CMOS current mirror. The proposed approach is based on utilizing body effect in a MOS transistor by connecting its gate and bulk terminals together for signal input. This results in boosting the effective transconductance of MOS transistor along with reduction of the threshold voltage. The proposed approach does not affect the DC gain of the current mirror. We demonstrate that the proposed approach features compatibility with widely used series-resistor technique for enhancing the current mirror bandwidth and both techniques have been employed simultaneously for maximum bandwidth enhancement. An important consequence of using both techniques simultaneously is the reduction of the series-resistor value for achieving the same bandwidth. This reduction in value is very attractive because a smaller resistor results in smaller chip area and less noise. PSpice simulation results using 180 nm CMOS technology from TSMC are included to prove the unique results. The proposed current mirror operates at 1Volt consuming only 102 µW and maximum bandwidth extension ratio of 1.85 has been obtained using the proposed approach. Simulation results are in good agreement with analytical predictions.

V. Niranjan

2014-09-01

109

Braking Resistor Switching By Genetic Algorithm Optimized Fuzzy Logic Controller In Multi-Machine Power System  

Science.gov (United States)

Fuzzy logic has been gaining increasing acceptance in control applications during the past few years. Usually, the membership functions and control rules of fuzzy logic controller are determined by trial and error which is cumbersome and time consuming. Therefore, to surmount such a drawback, this paper makes use of the Genetic Algorithm (GA) technique for optimal tuning of the parameters of the Fuzzy Logic Controller (FLC) used for the switching of the thyristor controlled braking resistor to improve power system transient stability. The braking resistor is installed at each generator bus, where rotor speed of the generator is measured to determine the firing-angle of the thyristor switch. By controlling the firing-angle of the thyristor, braking resistor controls the accelerating power in generators and thus improves the transient stability. The effectiveness of the proposed method has been demonstrated by considering 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 a multi-machine power system.

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

110

History of resistor array infrared projectors: hindsight is always 100% operability  

Science.gov (United States)

Numerous infrared scene projection technologies have been investigated since the 1970s. Notably, from the late 1980s the development of the first resistor array infrared projectors gained leverage from the strong concurrent developments within focal plane array imaging technology, linked by the common need for large integrated circuits comprising a 2-dimensional array of interconnected unit cells. In the resistor array case, it is the unit cell comprising the resistively heated emitter and its dedicated drive circuit that determines the projector response to its associated scene generator commands. In this paper we review the development of resistor array technology from a historical perspective, concentrating on the unit cell developments. We commence by describing the technological innovations that forged the way, sharing along the way stories of the successes and failures, all of which contributed to the steady if somewhat eventful growth of the critical knowledge base that underpins the strength of today's array technology. We conclude with comments on the characteristics and limitations of the technology and on the prospects for future array development.

Williams, Owen M.; Goldsmith, George C., II; Stockbridge, Robert G.

2005-05-01

111

Annealing effect on the electrical properties and microstructure of embedded Ni–Cr thin film resistor  

International Nuclear Information System (INIS)

Highlights: ? Annealing effect on the properties of embedded Ni–Cr thin film resistor. ? A good annealing condition was achieved. ? The rarely observed hexagonal Ni (0 1 1), (0 0 2) and (1 0 3) were found. ? The segregation of chromium in thin film can affect the resistivity and TCR. ? The results obtained would be helpful in achieving a good embedded resistor. - Abstract: Ni–Cr (80/20 at.%) alloy was deposited on the copper foil substrate as embedded thin film resistor (ETFR) materials by DC magnetron sputtering method. Electrical properties and microstructure of Ni–Cr ETFR under different annealing conditions were investigated. Results indicated that the ETFR exhibited the smallest temperature coefficient of resistance (TCR) after annealing at 250 °C for 540 s in N2. The structure, stress, composition and surface morphology of ETFR materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS) and atomic force microscopy (AFM). The rarely reported hexagonal Ni (0 1 1), (0 0 2) and (1 0 3) in Ni–Cr thin film were found in Ni–Cr (80/20 at.%) ETFR materials. The chemical states on the surface of the ETFR materials after annealing were mainly Cr2O3. The segregation of chromium during annealing can affect the resistivity and temperature coefficient of resistance (TCR). The different surface morphology of ETFR in annealing will affect the resistivitaffect the resistivity.

112

Framing the Digital Divide in Higher Education  

Directory of Open Access Journals (Sweden)

Full Text Available This is the introductory article to the monograph "Redefining the Digital Divide in Higher Education". The article describes a comprehensive approach to the phenomenon of the digital divide and digital access, based on Marc Raboy and Mark Warschauer's research. This approach depicts the evolution from mere physical access to effective use of information and communication technologies in the field of higher education. Within this framework, the articles in the monograph are presented highlighting their role in contributing to a comprehensive approach and reflection on the digital divide in Higher Education.

Ismael Peña-López

2010-01-01

113

Logic Gates Made of N-Channel JFETs and Epitaxial Resistors  

Science.gov (United States)

Prototype logic gates made of n-channel junction field-effect transistors (JFETs) and epitaxial resistors have been demonstrated, with a view toward eventual implementation of digital logic devices and systems in silicon carbide (SiC) integrated circuits (ICs). This development is intended to exploit the inherent ability of SiC electronic devices to function at temperatures from 300 to somewhat above 500 C and withstand large doses of ionizing radiation. SiC-based digital logic devices and systems could enable operation of sensors and robots in nuclear reactors, in jet engines, near hydrothermal vents, and in other environments that are so hot or radioactive as to cause conventional silicon electronic devices to fail. At present, current needs for digital processing at high temperatures exceed SiC integrated circuit production capabilities, which do not allow for highly integrated circuits. Only single to small number component production of depletion mode n-channel JFETs and epitaxial resistors on a single substrate is possible. As a consequence, the fine matching of components is impossible, resulting in rather large direct-current parameter distributions within a group of transistors typically spanning multiples of 5 to 10. Add to this the lack of p-channel devices to complement the n-channel FETs, the lack of precise dropping diodes, and the lack of enhancement mode devices at these elevated temperatures and the use of conventional direct coupled and buffered direct coupled logic gate design techniques is impossible. The presented logic gate design is tolerant of device parameter distributions and is not hampered by the lack of complementary devices or dropping diodes. In addition to n-channel JFETs, these gates include level-shifting and load resistors (see figure). Instead of relying on precise matching of parameters among individual JFETS, these designs rely on choosing the values of these resistors and of supply potentials so as to make the circuits perform the desired functions throughout the ranges over which the parameters of the JFETs are distributed. The supply rails V(sub dd) and V(sub ss) and the resistors R are chosen as functions of the distribution of direct-current operating parameters of the group of transistors used.

Krasowski, Michael J.

2008-01-01

114

Skew Divided Difference Operators and Schubert Polynomials  

Directory of Open Access Journals (Sweden)

Full Text Available We study an action of the skew divided difference operators on the Schubert polynomials and give an explicit formula for structural constants for the Schubert polynomials in terms of certain weighted paths in the Bruhat order on the symmetric group. We also prove that, under certain assumptions, the skew divided difference operators transform the Schubert polynomials into polynomials with positive integer coefficients.

Anatol N. Kirillov

2007-05-01

115

Divided difference operators for partial flag varieties  

OpenAIRE

Divided difference operators are degree-reducing operators on the cohomology of flag varieties that are used to compute algebraic invariants of the ring (for instance, structure constants). We identify divided difference operators on the equivariant cohomology of G/P for arbitrary partial flag varieties of arbitrary Lie type, and show how to use them in the ordinary cohomology of G/P. We provide three applications. The first shows that all Schubert classes of partial flag va...

Tymoczko, Julianna S.

2009-01-01

116

20 CFR 404.1207 - Divided retirement system coverage groups.  

Science.gov (United States)

...Divided retirement system coverage groups...Employees' Benefits SOCIAL SECURITY ADMINISTRATION ...Divided retirement system coverage groups. (a) General. Under section...divide a retirement system based on whether...

2010-04-01

117

Capacitive divider for output voltage measurement of intense electron beam accelerator  

International Nuclear Information System (INIS)

A kind of simple-mechanism, easy-disassembly self-integrating capacitive divider used for measuring diode output voltage of intense electron beam accelerator (IEBA) is developed. The structure of the capacitive divider is described, and the capacitance value of the capacitive divider is calculated by theoretical analysis and electromagnetic simulation. The dependence of measurement voltage on electrical parameters such as stray capacitance, earth capacitance of front resistance is obtained by PSpice simulation. Measured waveforms appear overshoot phenomenon when stray capacitance of front resistance is larger, and the wavefront will be affected when earth capacitance of front resistance is larger. The diode output voltage waveforms of intense electron beam accelerator, are measured by capacitive divider and calibrated by water resistance divider, which is accordance with that measured by a resistive divider, the division ratio is about 563007. The designed capacitive divider can be used to measure high-voltage pulse with 100 ns full width at half maximum. (authors)

118

Forking and dividing in Henson graphs  

OpenAIRE

For $n\\geq 3$, define $T_n$ to be the theory of the generic $K_n$-free graph, where $K_n$ is the complete graph on $n$ vertices. We prove a graph theoretic characterization of dividing in $T_n$, and use it to show that forking and dividing are the same for complete types. We then give an example of a forking and nondividing formula. Altogether, $T_n$ provides a counterexample to a recent question of Chernikov and Kaplan.

Conant, Gabriel

2014-01-01

119

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

120

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

OpenAIRE

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...

Schmidt, K. -h; Jurado, B.

2012-01-01

121

Dispersive dielectric and conductive effects in 2D resistor-capacitor networks  

International Nuclear Information System (INIS)

How to predict and better understand the effective properties of disordered material mixtures has been a long-standing problem in different research fields, especially in condensed matter physics. In order to address this subject and achieve a better understanding of the frequency-dependent properties of these systems, a large 2D L x L square structure of resistors and capacitors was used to calculate the immittance response of a network formed by random filling of binary conductor/insulator phases with 1000 ? resistors and 10 nF capacitors. The effects of percolating clusters on the immittance response were studied statistically through the generation of 10 000 different random network samples at the percolation threshold. The scattering of the imaginary part of the immittance near the dc limit shows a clear separation between the responses of percolating and non-percolating samples, with the gap between their distributions dependent on both network size and applied frequency. These results could be used to monitor connectivity in composite materials. The effects of the content and structure of the percolating path on the nature of the observed dispersion were investigated, with special attention paid to the geometrical fractal concept of the backbone and its influence on the behavior of relaxation-time distributions. For three different resistor-capacitor proportions, the appropriateness of many fitting models was investigated for modeling and analyzing individual ed for modeling and analyzing individual resistor-capacitor network dispersed frequency responses using complex-nonlinear-least-squares fitting. Several remarkable new features were identified, including a useful duality relationship and the need for composite fitting models rather than either a simple power law or a single Davidson-Cole one. Good fits of data for fully percolating random networks required two dispersive fitting models in parallel or series, with a cutoff at short times of the distribution of relaxation times of one of them. In addition, such fits surprisingly led to cutoff parameters, including a primitive relaxation or crossover time, with estimated values comparable to those found for real dispersive materials.

122

Ac transport studies in polymers by a resistor network and transfer matrix approaches application to polyaniline  

CERN Document Server

A statistical model of resistor network is proposed to describe a polymer structure and to simulate the real and imaginary components of its ac resistivity. It takes into account the polydispersiveness of the material as well as intrachain and interchain charge transport processes. By the application of a transfer matrix technique, it reproduces ac resistivity measurements carried out with polyaniline films in different doping degrees and at different temperatures. Our results indicate that interchain processes govern the resistivity behavior in the low frequency region while, for higher frequencies, intrachain mechanisms are dominant.

Nagashima, H N; Faria, R M

1998-01-01

123

Design of Improved Resistor Less 45NM Switched Inverter Scheme (SIS) Analog to Digital Converter  

OpenAIRE

This work presents three different approaches which eliminates the resistor ladder completely and hencereduce the power demand drastically of a Analog to Digital Converter. The first approach is SwitchedInverter Scheme (SIS) ADC; The test result obtained for it on 45nm technology indicates an offset error of0.014 LSB. The full scale error is of -0.112LSB. The gain error is of 0.07 LSB, actual full scale range of0.49V, worst case DNL & INL each of -0.3V. The power dissipation for the SIS ADC i...

Arun Kumar Sunaniya; Kavita Khare

2013-01-01

124

Quantum Resistor-Capacitor Circuit with Majorana Fermion Modes in a Chiral Topological Superconductor  

Science.gov (United States)

We investigate the mesoscopic resistor-capacitor circuit consisting of a quantum dot coupled to spatially separated Majorana fermion modes in a chiral topological superconductor. We find substantially enhanced relaxation resistance due to the nature of Majorana fermions, which are their own antiparticles and are composed of particle and hole excitations in the same abundance. Further, if only a single Majorana mode is involved, the zero-frequency relaxation resistance is completely suppressed due to a destructive interference. As a result, the Majorana mode opens an exotic dissipative channel on a superconductor which is typically regarded as dissipationless due to its finite superconducting gap.

Lee, Minchul; Choi, Mahn-Soo

2014-08-01

125

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

126

Using Shunt Resistor as a Current Transducer in Heavy-Duty Mobile Machine Drives  

OpenAIRE

This thesis investigates using a shunt resistor as a current transducer in the DC-DC converters, rectifiers and inverters of high-current heavy-duty mobile machine drives. There are two different measurement electronic circuits attached to the shunt. The performance of the shunt and these circuits are compared with an open-loop Hall sensor. This thesis describes the operating principle of Hall sensors and current shunts. In addition, the use of measured current in e.g. motor control is discus...

Niiranen, Oskari

2013-01-01

127

Carbon film resistor electrode for amperometric determination of acetaminophen in pharmaceutical formulations  

OpenAIRE

Flow injection analysis (FIA) with amperometric detection was employed for acetaminophen quantification in pharmaceutical formulations using a carbon film resistor electrode. This sensor exhibited sharp and reproducible current peaks for acetaminophen without chemical modification of its surface. A wide linear working range (8.0 × 10-7 to 5.0 × 10-4 mol L-1) in phosphate buffer solution as well as high sensitivity (0.143 A mol-1 L cm-2) and low submicromolar detection limit (1.36?...

Felix, Fabiana S.; Brett, Christopher M. A.; Angnes, Lu?cio

2007-01-01

128

Electrical Detection of Self-Assembled Polyelectrolyte Multilayers by a Thin Film Resistor  

CERN Document Server

The build up of polyelectrolyte multilayers (PEMs) was observed by a silicon-on-insulator (SOI) based thin film resistor. Differently charged polyelectrolytes adsorbing to the sensor surface result in defined potential shifts, which decrease with the number of layers deposited. We model the response of the device assuming electrostatic screening of polyelectrolyte charges by mobile ions within the PEMs. The Debye screening length inside the PEMs was found to be increased compared to the value corresponding to the bulk solution. Furthermore the partitioning of mobile ions between the bulk phase and the polyelectrolyte film was employed to calculate the dielectric constant of the PEMs and the concentration of mobile charges.

Neff, P A; Ecker, C; Nickel, B; Von Klitzing, R; Bausch, A R; Neff, Petra A.; Naji, Ali; Ecker, Christof; Nickel, Bert; Klitzing, Regine von; Bausch, Andreas R.

2006-01-01

129

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

130

Embedding the flag representation in divided powers  

OpenAIRE

A generalization of a theorem of Crabb and Hubbuck concerning the embedding of flag representations in divided powers is given, working over an arbitrary finite field F, using the category of functors from finite-dimensional F-vector spaces to F-vector spaces.

Powell, Geoffrey

2009-01-01

131

Computing ULV Decomposition by Divide Conquer Method  

Directory of Open Access Journals (Sweden)

Full Text Available The ULV decomposition (ULVD is an important member of a class of rank-revealing two-sided orthogonal decompositions used to approximate the Singular Value Decomposition (SVD. The ULVD can be modified much faster than the SVD. The accurate computation of the subspaces is required in applications in signal processing. In this study we introduce a divide conquer ULVD algorithm.

Hasan Erbay

2005-01-01

132

Compact chromium oxide thin film resistors for use in nanoscale quantum circuits  

Science.gov (United States)

We report on the electrical characterisation of a series of thin amorphous chromium oxide (CrOx) films, grown by dc sputtering, to evaluate their suitability for use as on-chip resistors in nanoelectronics. By increasing the level of oxygen doping, the room-temperature sheet resistance of the CrOx films was varied from 28 ?/? to 32.6 k ?/? . The variation in resistance with cooling to 4.2 K in liquid helium was investigated; the sheet resistance at 4.2 K varied with composition from 65 ?/? to above 20 G ?/? . All of the films measured displayed linear current-voltage characteristics at all measured temperatures. For on-chip devices for quantum phase-slip measurements using niobium-silicon nanowires, interfaces between niobium-silicon and chromium oxide are required. We also characterised the contact resistance for one CrOx composition at an interface with niobium-silicon. We found that a gold intermediate layer is favourable: the specific contact resistivity of chromium-oxide-to-gold interfaces was 0.14 m?cm2, much lower than the value for direct CrOx to niobium-silicon contact. We conclude that these chromium oxide films are suitable for use in nanoscale circuits as high-value resistors, with resistivity tunable by oxygen content.

Nash, C. R.; Fenton, J. C.; Constantino, N. G. N.; Warburton, P. A.

2014-12-01

133

SiMPl-An avalanche diode array with bulk integrated quench resistors for single photon detection  

Energy Technology Data Exchange (ETDEWEB)

The so-called silicon photomultipliers (SiPMs, MPPCs, etc.) are already replacing photomultiplier tubes in many applications. Still the reproducibility and the cost requirements are not at the level required for the coverage of many square meters of detector area. Therefore a simple technology is desired which allows a high yield and keeps the detector costs in a reasonable range. In the existing devices the need of high ohmic polysilicon for the quench resistors is one of the most yield and cost driving technological issues. We are proposing a front-side illuminated detector structure with quench resistors integrated into the silicon bulk. In this concept other obstacles for light like metal lines or contacts can be omitted and therefore the fill factor is only limited by the gaps necessary for optical cross-talk suppression. Within the array the entire surface area remains non-structured and can be easily coated with an anti-reflective layer. Compared to existing devices the proposed detector has the potential of higher photon detection efficiency especially in the blue and the UV range, an improved hardness against ionizing radiation and a much simpler processing resulting in a higher production yield and lower costs. The quenching mechanism has been demonstrated in a proof-of-principle production performed in house. The second prototype fabrication on silicon on isolator substrates has been done and allows testing of the device performance. The results from the first measurements are presented.

Ninkovic, Jelena, E-mail: ninkovic@mppmu.mpg.d [Max-Planck-Institut fuer Physik, Foehringer Ring 6, D-80805 Munich (Germany); Max-Planck-Institut Halbleiterlabor, Otto-Hahn-Ring 6, D-81739 Munich (Germany); Andricek, Ladislav; Liemann, Gerhard [Max-Planck-Institut fuer Physik, Foehringer Ring 6, D-80805 Munich (Germany); Max-Planck-Institut Halbleiterlabor, Otto-Hahn-Ring 6, D-81739 Munich (Germany); Lutz, Gerhard [PNSensor GmbH, Roemerstr. 28, D-80803 Munich (Germany); Moser, Hans-Guenther; Richter, Rainer [Max-Planck-Institut fuer Physik, Foehringer Ring 6, D-80805 Munich (Germany); Max-Planck-Institut Halbleiterlabor, Otto-Hahn-Ring 6, D-81739 Munich (Germany); Schopper, Florian [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Max-Planck-Institut Halbleiterlabor, Otto-Hahn-Ring 6, D-81739 Munich (Germany)

2010-05-21

134

Silicon photomultipliers with bulk-integrated quenching resistor: first results of characterization  

Energy Technology Data Exchange (ETDEWEB)

For future experiments in high energy physics detectors with high photon detection efficiencies (PDE) and ability to work in high magnetic fields are in the focus of research. Silicon photomultipliers (SiPM), arrays of Geiger-mode avalanche photodiodes, tend to replace conventional photomultiplier tubes in many applications. Conventional SiPMs use high-ohmic polysilicon as quenching resistor, which forms a barrier for incident light, thus decreasing the PDE. Furthermore it's also one of the cost driving technological issues in fabrication. By integrating the quenching resistor into the silicon bulk obstacles for light within the active area can be omitted and the fill factor of the device is only limited by the gaps necessary for optical crosstalk suppression. So this device is a promising candidate to achieve maximum PDE of up to 70%. In addition the absence of lateral high field regions on surface should improve the radiation hardness of the device. Results of the characterization of the in-house prototype production are presented.

Jendrysik, Christian; Andricek, Ladislav; Liemann, Gerhard; Moser, Hans-Guenther; Ninkovic, Jelena; Richter, Rainer [Max-Planck-Institut fuer Physik, Halbleiterlabor, Muenchen (Germany); Lutz, Gerhard [PNSensor GmbH, Muenchen (Germany)

2011-07-01

135

Resistance and Resistance Fluctuations in Random Resistor Networks Under Biased Percolation  

CERN Document Server

We consider a two-dimensional random resistor network (RRN) in the presence of two competing biased percolations consisting of the breaking and recovering of elementary resistors. These two processes are driven by the joint effects of an electrical bias and of the heat exchange with a thermal bath. The electrical bias is set up by applying a constant voltage or, alternatively, a constant current. Monte Carlo simulations are performed to analyze the network evolution in the full range of bias values. Depending on the bias strength, electrical failure or steady state are achieved. Here we investigate the steady-state of the RRN focusing on the properties of the non-Ohmic regime. In constant voltage conditions, a scaling relation is found between $/_0$ and $V/V_0$, where $$ is the average network resistance, $_0$ the linear regime resistance and $V_0$ the threshold value for the onset of nonlinearity. A similar relation is found in constant current conditions. The relative variance of resistance fluctuations als...

Pennetta, C; Trefan, G; Alfinito, E; Tref\\'an, Gy.

2002-01-01

136

Interface analysis of embedded chip resistor device package and its effect on drop shock reliability.  

Science.gov (United States)

In this study, the drop reliability of an embedded passive package is investigated under JESD22-B111 condition. Chip resistors were buried in a PCB board, and it was electrically interconnected by electroless and electrolytic copper plating on a tin pad of a chip resistor without intermetallic phase. However tin, nickel, and copper formed a complex intermetallic phase, such as (Cu, Ni)6Sn5, (Cu, Ni)3Sn, and (Ni, Cu)3Sn2, at the via interface and via wall after reflow and aging. Since the amount of the tin layer was small compared with the solder joint, excessive intermetallic layer growth was not observed during thermal aging. Drop failures are always initiated at the IMC interface, and as aging time increases Cu-Sn-Ni IMC phases are transformed continuously due to Cu diffusion. We studied the intermetallic formation of the Cu via interface and simulated the stress distribution of drop shock by using material properties and board structure of embedded passive boards. The drop simulation was conducted according to the JEDEC standard. It was revealed that the crack starting point related to failure fracture changed due to intermetallic phase transformation along the via interface, and the position where failure occurs experimentally agrees well with our simulation results. PMID:22849085

Park, Se-Hoon; Kim, Sun Kyoung; Kim, Young-Ho

2012-04-01

137

SiMPl—An avalanche diode array with bulk integrated quench resistors for single photon detection  

Science.gov (United States)

The so-called silicon photomultipliers (SiPMs, MPPCs, etc.) are already replacing photomultiplier tubes in many applications. Still the reproducibility and the cost requirements are not at the level required for the coverage of many square meters of detector area. Therefore a simple technology is desired which allows a high yield and keeps the detector costs in a reasonable range. In the existing devices the need of high ohmic polysilicon for the quench resistors is one of the most yield and cost driving technological issues. We are proposing a front-side illuminated detector structure with quench resistors integrated into the silicon bulk. In this concept other obstacles for light like metal lines or contacts can be omitted and therefore the fill factor is only limited by the gaps necessary for optical cross-talk suppression. Within the array the entire surface area remains non-structured and can be easily coated with an anti-reflective layer. Compared to existing devices the proposed detector has the potential of higher photon detection efficiency especially in the blue and the UV range, an improved hardness against ionizing radiation and a much simpler processing resulting in a higher production yield and lower costs. The quenching mechanism has been demonstrated in a proof-of-principle production performed in house. The second prototype fabrication on silicon on isolator substrates has been done and allows testing of the device performance. The results from the first measurements are presented.

Ninkovi?, Jelena; Andri?ek, Ladislav; Liemann, Gerhard; Lutz, Gerhard; Moser, Hans-Günther; Richter, Rainer; Schopper, Florian

2010-05-01

138

Low noise charge sensitive preamplifier DC stabilized without a physical resistor  

Science.gov (United States)

The invention is a novel charge sensitive preamplifier (CSP) which has no resistor in parallel with the feedback capacitor. No resetting circuit is required to discharge the feedback capacitor. The DC stabilization of the preamplifier is obtained by means of a second feedback loop between the preamplifier output and the common base transistor of the input cascode. The input transistor of the preamplifier is a Junction Field Transistor (JFET) with the gate-source junction forward biased. The detector leakage current flows into this junction. This invention is concerned with a new circuit configuration for a charge sensitive preamplifier and a novel use of the input Field Effect Transistor of the CSP itself. In particular this invention, in addition to eliminating the feedback resistor, eliminates the need for external devices between the detector and the preamplifier, and it eliminates the need for external circuitry to sense the output voltage and reset the CSP. Furthermore, the noise level of the novel CSP is very low, comparable with the performance achieved with other solutions. Experimental tests prove that this configuration for the charge sensitive preamplifier permits an excellent noise performance at temperatures including room temperature. An equivalent noise charge of less than 20 electrons r.m.s. has been measured at room temperature by using a commercial JFET as input device of the preamplifier.

Bertuccio, Giuseppe (Brianza, IT); Rehak, Pavel (Patchogue, NY); Xi, Deming (Beijing, CN)

1994-09-13

139

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

140

Using a photo-resistor to verify irradiance inverse square and Malus' laws  

Science.gov (United States)

In this article we present two single teaching experiments both related to light intensity measurements. These simple experiments can be conducted in order to train and teach other concepts and capabilities far exceeding those most obviously involved. The main problem presented to the students is that concerning the light detector. Our experiment uses an inexpensive, find to easy and trustable one, a photo-resistor. The student has to use some well suited method in order to calibrate the photo-resistor for intensities. We explore two methods to achieve this calibration, one very simple and with inexpensive materials and other with more expensive equipment. Afterwards, students proceed studying the behavior of the intensity of a point source with distance in order to verify the inverse square law, as well as the behavior of light intensity with the angle between the transmission axis of two linear polarizers, in order to verify the Malus' Law. Both experiments explore data treatment and graphics in order to choose the best method for the analysis. We present procedures and results obtained with these simple experiments.

Tavares, A. Dias; Sosman, L. P.; da Fonseca, R. J. M.; da Mota, L. A. C. P.; Muramatsu, M.

2008-04-01

141

Coulomb blockade and cotunneling in single electron circuits with on-chip resistors towards the implementation of R-pump  

CERN Document Server

We report on the investigation of Al single electron structures equipped with miniature (8 um long) on-chip Cr resistors of R > R_k = h/e^2 = 25.8 kOhm. From the measurement of the Coulomb blockade in single-junction structures we evaluated the self-capacitance of our resistors per unit length, c = 62 aF/um. We demonstrate that the cotunneling current in the transistor samples in the Coulomb blockade regime obeys the power law, $I \\propto V^{3+(R/R_k)}$, predicted by Odintsov, Bubanja and Schön for a transistor having pure ohmic-resistance leads. The concept of the three-junction single electron pump with on-chip resistors (R-pump) is developed. We demonstrate that the implementation of the R-pump with a relative accuracy of the electron transfer of 10^{-8} is quite feasible with the technology available.

Zorin, A B; Zangerle, H; Niemeyer, J C

1999-01-01

142

Disconnect switch for metal-clad, pressurized gas-insulated high-voltage switchgear with damping resistors  

Energy Technology Data Exchange (ETDEWEB)

A disconnect switch for metal-enclosed, compressed gas-insulated high-voltage switchgear has two resistors for the suppression of high-frequency oscillations caused by the occurence of a pre-flashover arc, each located along the longitudinal axis of and electrically connected to a movable rod. Furthermore, a movable insulating tube covers the disconnect gas substantially before the resistors make or break contact with each other. Each resistor is comprised of several resistive elements that lie adjacent to one another between two contact plates at each end and are molded of hardened cast resin. Each element is comprised of a ceramic plate with baked-on strips of resistive material that have contacts on all four edges.

Schulz, W.

1989-09-26

143

A real time status monitor for transistor bank driver power limit resistor in boost injection kicker power supply  

Energy Technology Data Exchange (ETDEWEB)

For years suffering of Booster Injection Kicker transistor bank driver regulator troubleshooting, a new real time monitor system has been developed. A simple and floating circuit has been designed and tested. This circuit monitor system can monitor the driver regulator power limit resistor status in real time and warn machine operator if the power limit resistor changes values. This paper will mainly introduce the power supply and the new designed monitoring system. This real time resistor monitor circuit shows a useful method to monitor some critical parts in the booster pulse power supply. After two years accelerator operation, it shows that this monitor works well. Previously, we spent a lot of time in booster machine trouble shooting. We will reinstall all 4 PCB into Euro Card Standard Chassis when the power supply system will be updated.

Mi, J.; Tan, Y.; Zhang, W.

2011-03-28

144

An evaluation of a translator for finite element data to resistor/capacitor data for the heat diffusion equation  

Energy Technology Data Exchange (ETDEWEB)

This paper evaluates a translator for finite element data to resistor/capacitor data (FEM/RC) for the numerical solution of heat diffusion problems. The translator involves the derivation of thermal resistors and capacitors, implicit in the heat balance formulation of the finite difference method. It uses a finite element mesh, which consists of nodes and elements and is implicit in the Galerkin finite element method (GFEM). This hybrid translation method, FEM/RC, has been incorporated in Q/TRAN, a new Q/TRAN, HEATING-6, and a research code employing GFEM on a purely mathematical, highly nonlinear steady-state conduction benchmark problem. The evaluation concludes that the FEM/RC technique has numerical characteristics that are consistent with comparable schemes for the benchmark problem. FEM/RC also accurately translates skewed meshes. Because FEM/RC generates resistors and capacitors, it appears to offer a more computationally efficient method than the classical GFEM. 9 figs., 2 tabs.

1987-01-01

145

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

146

High-temperature anomalies in resistivity and thermoelectric power of thick-film resistors and their conduction mechanism  

Science.gov (United States)

Resistivity and thermoelectric power S of RuO2-based thick-film resistors were measured in tempera- ture range T = 77-1100 K. Sharp maxima of and S occur at 1000 K. = 7.5 × 103 cm and S = +90 V/K at the maxima, while = 2.5 × 103 cm and S =+10V/K at room temperature. Thermoelectric power becomes negative at temperatures in the range 700-800K and 1000-1070K. It is assumed that the peculiarities of and S are caused by structural changes in compounds of the lead-silicate glass used in the thick-film resistors.

Abdurakhmanov, G.; Abdurakhmanova, N. G.

2005-07-01

147

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

148

Improvement in the voltage grading (axial and radial) of the generator column of a Van de Graaf generator by the use of a resistor chain  

International Nuclear Information System (INIS)

It is well known that the use of a series of resistors, connected between the equipotential rings of a Van de Graaff generator, improves the axial voltage grading of the generator. The work reported in this paper shows how the resistor chain also improves the radial voltage gradient. The electrolytic field mapping technique was adopted in the present work. (Auth.)

149

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

150

Fabrication of superconductive tunneling junction resistors and short circuits by ion implantation  

International Nuclear Information System (INIS)

A superconductive junction device for fabricating Josephson integrated circuits is useful for replacing deposited thin-film resistors and for short-circuit device interconnections. Derived by ''poisoning'' a superconductive electrode or altering the barrier of a tunnel junction, the device displays controllable resistive properties at normal superconducting transition temperatures at substantial savings in the space occupied. Methods of fabricating the device using the selective niobium anodization process and ion implantation process are disclosed. When both upper and lower superconductive electrodes are poisoned, the device has linear properties whose resistance is identical to the normal resistance of unpoisoned junctions. Superconducting short circuits are readily obtained by oxygen ion implantation in thin film niobium electrodes

151

A High-Swing OTA with wide Linearity for design of self-tunable linear resistor  

Directory of Open Access Journals (Sweden)

Full Text Available Low power consumption, long battery life and portability are essential requirements of modern healthmonitoring products. Operational Transconductance Amplifier (OTA operating in subthreshold region isan basic building block for low power health monitoring products design. An modified design of OTAwhich incorporates better linearity and increased output impedance has been discussed in this paper. Theproposed OTA uses High-swing improved-Wilson current mirror for low power and low-frequencyapplications. The achieved linearity is about ± 1.9 volt and unity gain bandwidth (UGB of 342.30 KHz atpower supply of 0.9 volt which makes OTA to consume power in range of nanowatts. The proposed lowvoltage OTA implementation in design of self- tunable linear resistor has been presented in this paper. Thecircuit implementation has been done using standard 0.18 micron technology provided by TSMC on BSIM3v3 level-53 model parameter and verified results through use of ELDO Simulator.

Nikhil Raj

2010-09-01

152

Resistor-logic demultiplexers for nanoelectronics based on constant-weight codes.  

Science.gov (United States)

The voltage margin of a resistor-logic demultiplexer can be improved significantly by basing its connection pattern on a constant-weight code. Each distinct code determines a unique demultiplexer, and therefore a large family of circuits is defined. We consider using these demultiplexers for building nanoscale crossbar memories, and determine the voltage margin of the memory system based on a particular code. We determine a purely code-theoretic criterion for selecting codes that will yield memories with large voltage margins, which is to minimize the ratio of the maximum to the minimum Hamming distance between distinct codewords. For the specific example of a 64 × 64 crossbar, we discuss what codes provide optimal performance for a memory. PMID:21727381

Kuekes, Philip J; Robinett, Warren; Roth, Ron M; Seroussi, Gadiel; Snider, Gregory S; Stanley Williams, R

2006-02-28

153

Highly tunable local gate controlled complementary graphene device performing as inverter and voltage controlled resistor.  

Science.gov (United States)

Using single-layer CVD graphene, a complementary field effect transistor (FET) device is fabricated on the top of separated back-gates. The local back-gate control of the transistors, which operate with low bias at room temperature, enables highly tunable device characteristics due to separate control over electrostatic doping of the channels. Local back-gating allows control of the doping level independently of the supply voltage, which enables device operation with very low VDD. Controllable characteristics also allow the compensation of variation in the unintentional doping typically observed in CVD graphene. Moreover, both p-n and n-p configurations of FETs can be achieved by electrostatic doping using the local back-gate. Therefore, the device operation can also be switched from inverter to voltage controlled resistor, opening new possibilities in using graphene in logic circuitry. PMID:24013367

Kim, Wonjae; Riikonen, Juha; Li, Changfeng; Chen, Ya; Lipsanen, Harri

2013-10-01

154

Highly tunable local gate controlled complementary graphene device performing as inverter and voltage controlled resistor  

International Nuclear Information System (INIS)

Using single-layer CVD graphene, a complementary field effect transistor (FET) device is fabricated on the top of separated back-gates. The local back-gate control of the transistors, which operate with low bias at room temperature, enables highly tunable device characteristics due to separate control over electrostatic doping of the channels. Local back-gating allows control of the doping level independently of the supply voltage, which enables device operation with very low VDD. Controllable characteristics also allow the compensation of variation in the unintentional doping typically observed in CVD graphene. Moreover, both p–n and n–p configurations of FETs can be achieved by electrostatic doping using the local back-gate. Therefore, the device operation can also be switched from inverter to voltage controlled resistor, opening new possibilities in using graphene in logic circuitry. (paper)

155

Nonuniformity correction of, and calibrated projection with, a resistor array infrared scene projector  

Science.gov (United States)

Kinetic energy weapon (KEW) programs under the Ballistic Missile Defense Office (BMDO) need high fidelity, fast framing infrared (IR) imaging seekers. As imaging sensors have matured to support BMDO, the complexity of functions assigned to the KEW weapon systems has amplified the necessity for robust hardware-in-the-loop (HWIL) simulation facilities to reduce program risk. The IR projector, an integral component of a HWIL simulation, must reproduce the real world with enough fidelity that the unit under test's (UUT) software will respond to the projected scenario of images as though it were viewing the real world. The CMOS resistor array IR scene projector, a wideband flickerless technology, shows great promise in cryogenic vacuum chamber as well as room temperature testing. A 128 X 128 CMOS resistor array has undergone extensive characterization measurements at Eglin AFB to determine its potential for HWIL testing of BMDO IR seekers. This paper addresses the nonuniformity correction (NUC) and use of the array in a calibrated projection test. The methodology and process for the NUC is described. Sensitivities to such things as output averaging, and optical sampling are explained. With the NUC procedure established, a test was accomplished that provided calibrated scene radiance values to a UUT. Absolute radiance values were not projected. Rather, the array's low and high output capabilities were equated to the low and high radiance values of an input scene. A calibration curve was established that allowed the UUT's output to be equated to the input scene's radiance values. The input scene was projected to the UUT, and the scene's radiance values were reproduced after applying the calibration curve to the UUT's output response. To the authors' knowledge, this if the first accomplishment of such a test with a dynamic IR scene projector.

Jones, Lawrence E.; Olson, Eric M.; Kircher, James R.; Stockbridge, Robert G.

1995-06-01

156

Characterization measurements of the wideband infrared scene projector resistor array: II  

Science.gov (United States)

Kinetic Energy Weapon (KEW) program under the Ballistic Missile Defense Office (BMDO) need high fidelity, fast framing infrared (IR) imaging seekers. As imaging sensors have matured to support BMDO, the complexity of functions assigned to the KEW weapon systems has amplified the necessity for robust hardware-in-the-loop (HWIL) simulation facilities to reduce program risk. Tactical weapon systems are also turning to imaging focal plane array seekers. They too require more sophisticated HWIL testing. The IR projector, an integral component of a HWIL simulation, must reproduce the real world with enough fidelity that the unit- under-test's software will respond to the projected scenario of images as through it were viewing the real world. The MOSFET resistor array IR scene projector shows great promise in cryogenic vacuum chamber as well as room temperature testing. Under the Wideband Infrared Scene Projector (WISP) program, a second generation resistor array has been delivered and characterized. Characterization measurements to include: spectral output, dynamic range capability, apparent temperature, rise time, and fall time, have been accomplished on the second generation array at the Kinetic Kill Vehicle Hardware-in-the Loop Simulator facility and the Guided Weapons Evaluation Facility, Eglin AFB, FL. Dynamic range output exceeds to WISP specification. Other parameters such as, rise time etc., either meet or are close to meeting system specifications. The final design of the WISP arrays is currently in progress based on these results. Also reported on in this document are performance measurements of the analog drive electronics' noise level, accuracy and resolution. The performance of the drive electronics had to be established before any radiometric output could be measured.

Jones, Lawrence E.; Stockbridge, Robert G.; Andrews, Allen R.; Herald, W. Larry; Guertin, Andrew W.

1997-07-01

157

Thermocapillary actuation by optimized resistor pattern: bubbles and droplets displacing, switching and trapping.  

Science.gov (United States)

We report a novel method for bubble or droplet displacement, capture and switching within a bifurcation channel for applications in digital microfluidics based on the Marangoni effect, i.e. the appearance of thermocapillary tangential interface stresses stemming from local surface tension variations. The specificity of the reported actuation is that heating is provided by an optimized resistor pattern (B. Selva, J. Marchalot and M.-C. Jullien, An optimized resistor pattern for temperature gradient control in microfluidics, J. Micromech. Microeng., 2009, 19, 065002) leading to a constant temperature gradient along a microfluidic cavity. In this context, bubbles or droplets to be actuated entail a surface force originating from the thermal Marangoni effect. This actuator has been characterized (B. Selva, I. Cantat, and M.-C. Jullien, Migration of a bubble towards a higher surface tension under the effect of thermocapillary stress, preprint, 2009) and it was found that the bubble/droplet (called further element) is driven toward a high surface tension region, i.e. toward cold region, and the element velocity increases while decreasing the cavity thickness. Taking advantage of these properties three applications are presented: (1) element displacement, (2) element switching, detailed in a given range of working, in which elements are redirected towards a specific evacuation, (3) a system able to trap, and consequently stop on demand, the elements on an alveolus structure while the continuous phase is still flowing. The strength of this method lies in its simplicity: single layer system, in situ heating leading to a high level of integration, low power consumption (P < 0.4 W), low applied voltage (about 10 V), and finally this system is able to manipulate elements within a flow velocity up to 1 cm s(-1). PMID:20445893

Selva, Bertrand; Miralles, Vincent; Cantat, Isabelle; Jullien, Marie-Caroline

2010-07-21

158

Technical-economic evaluation of the utilization of closing resistor in CEMIG extra-high voltage circuit breakers  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the technical and economic studies performed by CEMIG, Companhia Energetica de Minas Gerais, Brazil, concerning the use of closing resistor in its extra-high voltage (EHV) breakers. The analysis emphasizes the advantages which could be achieved with the elimination of the resistor as far as costs and reliability are concerned. This evaluation was motivated by two 500 kV breaker failures resulting from the breakdown of the closing resistor operation mechanism. These occurrences resulted in operative restriction for CEMIG EHV system. The analysis demanded a review of the capability criteria of silicon carbide (Si C) gap arresters, which are still greatly used in CEMIG EHV System, and of the procedures to be applied when carrying out the transient studies. The investigation resulted in the prompt removal of closing resistors from circuit breakers in CEMIG extra-high voltage system generating an economy of approximately U$ 840,00 and an improvement in safety and system reliability. (author) 13 refs., 4 figs., 1 tab.

Rocha, Angelica C.O.; Pinto, Roberto del Giudice R.; Teixeira, Jose Cleber; Fonseca, Rodrigo Assuncao; F. Junior, Sebastiao V. [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil)

1994-12-31

159

Divided edge bundling for directional network data.  

Science.gov (United States)

The node-link diagram is an intuitive and venerable way to depict a graph. To reduce clutter and improve the readability of node-link views, Holten & van Wijk's force-directed edge bundling employs a physical simulation to spatially group graph edges. While both useful and aesthetic, this technique has shortcomings: it bundles spatially proximal edges regardless of direction, weight, or graph connectivity. As a result, high-level directional edge patterns are obscured. We present divided edge bundling to tackle these shortcomings. By modifying the forces in the physical simulation, directional lanes appear as an emergent property of edge direction. By considering graph topology, we only bundle edges related by graph structure. Finally, we aggregate edge weights in bundles to enable more accurate visualization of total bundle weights. We compare visualizations created using our technique to standard force-directed edge bundling, matrix diagrams, and clustered graphs; we find that divided edge bundling leads to visualizations that are easier to interpret and reveal both familiar and previously obscured patterns. PMID:22034356

Selassie, David; Heller, Brandon; Heer, Jeffrey

2011-12-01

160

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

161

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

162

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.

1017-10-01

163

Superconducting switching circuit, memory cell and memory circuit, with resonance damping resistors  

International Nuclear Information System (INIS)

This patent describes a superconducting switching circuit comprising: first and second Josephson junction elements connected in series; first and second excitation inductors connected in series to each other and connected in series to the first and second Josephson junction elements; an exciting line magnetically coupled to the first and second excitation inductors; a load inductor having a first end connected to a connecting point of the first and second Josephson junction elements and having a second end connected to a connecting point of the first and second excitation inductors; an input signal line coupled to the load inductor; and first and second resistors connected, respectively, to a first current path including at least the first Josephson junction element and a second current path including at least the second Josephson junction element thereby effecting suppression of unwanted resonance in the current paths, wherein the first and second current paths belonging to the circuit including the first and second Josephson elements, the first and second excitation inductors and the load inductor

164

Combined TiN- and TaN temperature compensated thin film resistors  

Energy Technology Data Exchange (ETDEWEB)

The opposite signs of the temperature coefficient of resistance (TCR) of two thin film materials, titanium nitride (TiN) and tantalum nitride (TaN), were used to form temperature compensated thin film resistors (TFRs). The principle of designing temperature compensated TFRs by connecting TFRs of each compound in series or in parallel was demonstrated. TiN, TaN, and combined TiN and TaN TFRs for monolithic microwave integrated circuits (MMICs) were fabricated by reactive sputtering. DC characterization was performed over the temperature range of 30-200 Degree-Sign C. The TiN TFRs exhibited an increase in resistivity with temperature with TCRs of 540 and 750 ppm/ Degree-Sign C. The TaN TFR on the other hand exhibited a negative TCR of - 470 ppm/ Degree-Sign C. The shunted TFRs were fabricated by serial deposition of TiN and TaN to form a bilayer component. The TCRs of the series- and shunt configurations were experimentally reduced to - 60 and 100 ppm/ Degree-Sign C, respectively. The concept of temperature compensation was used to build a Wheatstone bridge with an application in on-chip temperature sensing.

Malmros, Anna, E-mail: anna.malmros@chalmers.se; Andersson, Kristoffer; Rorsman, Niklas

2012-01-01

165

1/f noise in ion-implanted resistors between 77 and 300 K  

Science.gov (United States)

The conductivity, the Hall effect, and the noise of ion-implanted resistors is measured between 77 and 300 K. The temperature dependence of the carrier concentration in these boron-doped layers cannot be explained by the freeze-out of the boron acceptor level. Possible explanations are a temperature-dependent Hall factor r and a distribution of trap levels 0.1-0.2 eV above the valence-band edge. The mobility ? can be determined from the conductivity and the Hall-effect data. The mobility shows the highest value after annealing at 750 °C. The value of the 1/f noise parameter ? shows a weak temperature dependence after annealing at 450, 550, 650, and 900 °C. After annealing at 750 °C the ? value decreases from 10-5 at 300 K to lower than 2×10-7 at 77 K. The highest mobility ? gives the lowest 1/f noise parameter ?. This indicates that more defects and lattice damage give more 1/f noise. Additional scattering mechanisms have much more influence on the 1/f noise parameter ? than on the mobility ?.

Clevers, R. H. M.

1987-09-01

166

Combined TiN- and TaN temperature compensated thin film resistors  

International Nuclear Information System (INIS)

The opposite signs of the temperature coefficient of resistance (TCR) of two thin film materials, titanium nitride (TiN) and tantalum nitride (TaN), were used to form temperature compensated thin film resistors (TFRs). The principle of designing temperature compensated TFRs by connecting TFRs of each compound in series or in parallel was demonstrated. TiN, TaN, and combined TiN and TaN TFRs for monolithic microwave integrated circuits (MMICs) were fabricated by reactive sputtering. DC characterization was performed over the temperature range of 30–200 °C. The TiN TFRs exhibited an increase in resistivity with temperature with TCRs of 540 and 750 ppm/°C. The TaN TFR on the other hand exhibited a negative TCR of ? 470 ppm/°C. The shunted TFRs were fabricated by serial deposition of TiN and TaN to form a bilayer component. The TCRs of the series- and shunt configurations were experimentally reduced to ? 60 and 100 ppm/°C, respectively. The concept of temperature compensation was used to build a Wheatstone bridge with an application in on-chip temperature sensing.

167

Circuit proposition for copying the value of a resistor into a memristive device supported by HSPICE simulation  

OpenAIRE

Memristor is the fourth fundamental passive circuit element with potential applications in development of analog memories, artificial brains (with the capacity of hardware training) and neuro-science. In most of these applications the memristance of the device should be set to the desired value, which is currently performed by trial and error. The aim of this paper is to propose a circuit for copying the value of the given resistor into a memristive device. HSPICE simulation...

Merrikh-bayat, Farshad; Mirebrahimi, Nafiseh; Bayat, Farhad

2013-01-01

168

Properties and stability of thick-film resistors with low processing temperatures - effect of composition and processing parameters  

OpenAIRE

In this work, the properties (sheet-resistance, temperature coefficient and piezoresistance / gauge factor) and stability of thick-film resistors with low firing temperatures (525...650°C) are studied. To this end, two low-melting lead borosilicate glass composition have been chosen, together with RuO2 as a conductive filler. The effect on the properties and stability of composition and firing temperature is studied. The stability of the materials is quantified during high-temperature storag...

Vionnet-menot, Sonia; Maeder, Thomas; Grimaldi, Claudio; Jacq, Caroline; Ryser, Peter

2005-01-01

169

Cross-Bridge Kelvin resistor structures for reliable measurement of low contact resistances and contact interface characterization  

OpenAIRE

The parasitic factors that strongly influence the measurement accuracy of Cross-Bridge Kelvin Resistor (CBKR) structures for low specific contact resistances (rhoc) have been extensively discussed during last few decades and the minimum of the rhoc value, which could be accurately extracted, was estimated. We fabricated a set of various metal-to-metal CBKR structures with different geometries, i.e., shapes and dimensions, to confirm this limit experimentally and to create a method for contact...

Stavitski, N.; Klootwijk, J. H.; Zeijl, H. W.; Kovalgin, A. Y.; Wolters, R. A. M.

2009-01-01

170

Features of the current-voltage characteristics of the resistors made by 'silicon with dielectric isolation' technology at high densities of leaking current  

International Nuclear Information System (INIS)

Investigation of current-voltage characteristics of diffusion resistors, made by 'Silicon with dielectric isolation' technology with leaking current density till 105A/sm2 and different geometrical characteristics were conducted

171

An evaluation of a translator for finite element data to resistor/capacitor data for the heat diffusion equation  

International Nuclear Information System (INIS)

This paper evaluates a translator for finite element data to resistor/capacitor data (FEM/RC) for the numerical solution of heat diffusion problems. The translator involves the derivation of thermal resistors and capacitors, implicit in the heat balance formulation of the finite difference method. It uses a finite element mesh, which consists of nodes and elements and is implicit in the Galerkin finite element method (GFEM). This hybrid translation method, FEM/RC, has been incorporated in Q/TRAN, a new thermal analysis computer code. This evaluation compares Q/TRAN, HEATING-6, and a research code employing GFEM on a purely mathematical, highly nonlinear steady-state conduction benchmark problem. The evaluation concludes that the FEM/RC technique has numerical characteristics that are consistent with comparable schemes for the benchmark problem. FEM/RC also accurately translates skewed meshes. Because FEM/RC generates resistors and capacitors, it appears to offer a more efficient method than the classical GFEM

172

Development of high voltage surge limiting resistor for protection of HV multiplier of 3 MeV DC accelerator  

International Nuclear Information System (INIS)

A 3MeV, 10mA DC electron beam accelerator is in commissioning stages at EBC, Kharghar, Navi Mumbai. The accelerating potential of -3MV is generated by a Parallel Coupled Voltage Multiplier (PCVM) scheme using 74 stages of HV rectifier stacks in the 6 kg/cm2 SF6 gas environment. The HV surges of order of 600kV, 42kA, 10ns is estimated across the rectifier stacks during sparking in the multiplier column. To limit the surge current and protect the rectifier diodes, a non inductive thick film surge limiting resistor (SLR) and protective spark gap is designed and developed. The rectifier stacks with surge limiting resistors at both the ends and protective spark gap in parallel has been successfully tested in simulated surge condition at an impulse voltage of 212kVp, 150ns FWHM and surge energy of 200J, 10ms, 20kV at 6kg/cm2 SF6 gas environment and found satisfactorily. Subsequently the HV multiplier was installed with this surge protection scheme and is being tested at 1.2 MeV level. This paper describes the design features and test results of the non-inductive surge limiting resistor. (author)

173

Effects of a parallel resistor on electrical characteristics of a piezoelectric transformer in open-circuit transient state.  

Science.gov (United States)

This paper investigates electrical transient characteristics of a Rosen-type piezoelectric transformer (PT), including maximum voltages, time constants, energy losses and average powers, and their improvements immediately after turning OFF. A parallel resistor connected to both input terminals of the PT is needed to improve the transient characteristics. An equivalent circuit for the PT is first given. Then, an open-circuit voltage, involving a direct current (DC) component and an alternating current (AC) component, and its related energy losses are derived from the equivalent circuit with initial conditions. Moreover, an AC power control system, including a DC-to-AC resonant inverter, a control switch and electronic instruments, is constructed to determine the electrical characteristics of the OFF transient state. Furthermore, the effects of the parallel resistor on the transient characteristics at different parallel resistances are measured. The advantages of adding the parallel resistor also are discussed. From the measured results, the DC time constant is greatly decreased from 9 to 0.04 ms by a 10 k(omega) parallel resistance under open output. PMID:17225805

Chang, Kuo-Tsai

2007-01-01

174

A Compound Generic Quantitative Framework for Measuring Digital Divide  

Directory of Open Access Journals (Sweden)

Full Text Available The term digital divide had been used in the literature to conceptualize the gap in using and utilizing information and communication technologies. Digital divide can be identified on different levels such as individuals, groups, societies, organizations and countries. On the other hand, the concept of e-Inclusion is coined to define activities needed to bridge digital divide. One of the most challenging research areas in digital divide that had been a subject for exhaustive studies is measuring digital divide. Researchers have proposed many metrics and indices to measure digital divide. However, most of the proposed measures are bivariate comparisons that reduce measurement to comparisons of Internet penetration rates or alike. This paper proposes a compound generic framework for quantitative measuring of digital divide on the individuals or group level. The proposed framework takes into account the context of the digital divide in each society.

Noureldien A. Noureldien

2014-07-01

175

Policy Options to Combat the Digital Divide in Western Europe  

Directory of Open Access Journals (Sweden)

Full Text Available This paper reviews the digital divide in Western Europe, as well as policy options for combating that divide. While age, income and gender are significant predictors of the digital divide in Western Europe, geography plays a crucial role. The countries in Southern Europe have less computer and Internet penetration than their Northern European counterparts. The paper then discusses four policy options for combating the divide, suggesting that the most effective solution would be private/public partnerships.

Rod Carveth

2002-01-01

176

A Compound Generic Quantitative Framework for Measuring Digital Divide  

OpenAIRE

The term digital divide had been used in the literature to conceptualize the gap in using and utilizing information and communication technologies. Digital divide can be identified on different levels such as individuals, groups, societies, organizations and countries. On the other hand, the concept of e-Inclusion is coined to define activities needed to bridge digital divide. One of the most challenging research areas in digital divide that had been a subject for exhaustive studies is measur...

Noureldien, Noureldien A.

2014-01-01

177

Can Water Store Charge?  

OpenAIRE

Previous work from this and other laboratories has demonstrated large pH gradients in water. Established by passing current between immersed electrodes, pH gradients between electrodes were found to disappear slowly, persisting for tens of minutes after the current had been turned off. We find here that these pH gradients reflect a genuine separation of charge: at times well after disconnection of the power supply, current could be drawn through a resistor placed between the charging electrod...

Ovchinnikova, Kate; Pollack, Gerald H.

2009-01-01

178

Investigation of the optical sampling between the infrared resistor array projector and the unit under test for hardware-in-the-loop testing  

Science.gov (United States)

Kinetic Energy Weapon (KEW) programs under the Ballistic Missile Defense Office (BMDO) need high fidelity, fast framing infrared (IR) imaging seekers. As imaging sensors have matured to support BMDO, the complexity of functions assigned to KEW weapon systems has amplified the necessity for robust hardware-in-the-loop (HWIL) simulation facilities to reduce program risk. The IR projector, an integral component of a HWIL simulation, must reproduce the real world with enough fidelity that the unit under test's software will respond to the projected scenario of images as though it were viewing the real world. The MOSFET resistor array IR scene projector shows great promise for both cryogenic vacuum chamber and room temperature testing. The resistor array breaks up the analog world into discrete pieces, much like a focal plane array (FPA). Extensive debate has taken place since the inception of the resistor array as to how many resistors need to be projected into one FPA detector. Can one resistor be matched to one FPA detector, or does the Nyquist rate of at least 2:1 sampling take precedence? Testing was accomplished at the Wright Laboratory Kinetic Kill Vehicle Hardware-in-the-Loop Simulator that utilized a 5:1 zoom collimator and the Wideband Infrared Scene Projector resistor array to project in the 1:1, 1.3:1, 2:1, and 3:1 cases. This paper discusses the results of those tests.

Jones, Lawrence E.; Olson, Eric M.; Murrer, Robert Lee, Jr.

1996-05-01

179

Bridging the Organizational Divide: Toward a Comprehensive Approach to the Digital Divide. A PolicyLink Report.  

Science.gov (United States)

This report discusses innovative uses of information technology by community based organizations, examining how to develop a comprehensive policy agenda for bridging the digital divide. It begins by presenting background information on the digital divide as context for understanding the organizational divide. Next, it discusses challenges facing…

Kirschenbaum, Josh; Kunamneni, Radhika

180

Bridging the Digital Divide: – A Myth or Reality ?  

Directory of Open Access Journals (Sweden)

Full Text Available Researchers have been documenting about the digital divide between developing countries and developed countries since 1970’s. Some experts in areas like Public Policy, Communications, Business Management and Economics have also addressed the phenomenon of digital divide since the 1990’s. We are in the 21st century and still there is the same old talk of digital divide amongst these researchers. One wonders whether digital divide will continue forever and whether we will ever achieve a Technology that closes this gap. This paper attempts to investigate ways to bridge the digital divide between Developing and Developed Countries and explore facts about Digital Divide that might be of some interest to the reader. The contribution of this paper is in the way this digital divide can be perceived as a reality or a myth given the number of years that have elapsed since this term was first coined by Lloyd Morrisett

Zablon Akoko Mbero

2013-06-01

181

Gentilly-2 and Point Lepreau divider plate replacement  

International Nuclear Information System (INIS)

The steam generators at Hydro Quebec's Gentilly-2 and New Brunswick Power's Point Lepreau Nuclear Plants have been in operation since 1983, and were built with primary divider plates of a bolted panel configuration. During a routine outage inspection at Gentilly-2, it was noted that two bolts had dislodged from the divider plate and were located lying in the primary head. Subsequent inspections revealed erosion damage to a a substantial number of divider plate bolts and to a lesser extent, to the divider plate itself. After further inspection and repair the units were returned to operation, however, it was determined that a permanent replacement of the primary divider plates was going to be necessary. Upon evaluation of various options, it was decided that the panel type divider plates would be replaced with a single piece floating design. The divider plate itself was to be of one piece all-welded arrangement to be constructed from individual panels to be brought in through the manways. In view of the strength limitations of the bolted attachment of the upper seat bar to the tubesheet, a new welded seat was was provided. To counteract erosion concerns, the new divider plate is fitted with erosion resistant inserts of weld buildup and with improved sealing features in order to minimize leakage and erosion. At an advanced stage in the design and manufacture of the components, the issue of divider plate strength during loss of coolant accident (LOCA) conditions came into focus. Analysis was performed to determine the strength and/or failure characteristics of the divider plate to a variety of small and large LOCA conditions. Subsequently, Point Lepreau decided to replace their divider plates to address LOCA concerns. The paper describes the diagnosis of the original divider plates and the design. manufacture, field mobilization, installation and subsequent operation of the replacement divider plates. (author)

182

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 ...

183

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

184

Hybrid voltage divider used for high voltage pulsed power measurement  

International Nuclear Information System (INIS)

The principle and structure of a hybrid voltage divider are proposed and the calibration and experimental testing are carried out. The ideal response conditions of the divider are analyzed by using the simplified divider model, the attenuation characteristic of two-stage voltage dividing is discussed, and then an error control method is presented. Through load calibration, the pulsed voltage frequency response of the divider can be greater than 2.9 MHz with the largest pulse width of 40 ?s, the attenuation ratio (or the attenuation coefficient) of 2. 60 kV/V and the measurement error of less than 5%. The divider has the merits of low cost, easy fabrication, and being capable of ns-to ?s-level pulsed voltage measurement, and it can be applied to laboratory- scale pulsed power measurement. (authors)

185

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

186

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

Science.gov (United States)

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.

Stratos, David; Maria, Georgiou; Eleftherios, Fysikopoulos; George, Loudos

2013-02-01

187

Calculating electronic tunnel currents in networks of disordered irregularly shaped nanoparticles by mapping networks to arrays of parallel nonlinear resistors  

International Nuclear Information System (INIS)

We have shown both theoretically and experimentally that tunnel currents in networks of disordered irregularly shaped nanoparticles (NPs) can be calculated by considering the networks as arrays of parallel nonlinear resistors. Each resistor is described by a one-dimensional or a two-dimensional array of equal size nanoparticles that the tunnel junction gaps between nanoparticles in each resistor is assumed to be equal. The number of tunnel junctions between two contact electrodes and the tunnel junction gaps between nanoparticles are found to be functions of Coulomb blockade energies. In addition, the tunnel barriers between nanoparticles were considered to be tilted at high voltages. Furthermore, the role of thermal expansion coefficient of the tunnel junction gaps on the tunnel current is taken into account. The model calculations fit very well to the experimental data of a network of disordered gold nanoparticles, a forest of multi-wall carbon nanotubes, and a network of few-layer graphene nanoplates over a wide temperature range (5-300?K) at low and high DC bias voltages (0.001?mV–50?V). Our investigations indicate, although electron cotunneling in networks of disordered irregularly shaped NPs may occur, non-Arrhenius behavior at low temperatures cannot be described by the cotunneling model due to size distribution in the networks and irregular shape of nanoparticles. Non-Arrhenius behavior of the samples at zero bias voltage limit was attributed to the disorder in the samples. Unlike the electron cotunneling model, we found that the crossover from Arrhenius to non-Arrhenius behavior occurs at two temperatures, one at a high temperature and the other at a low temperature.

188

Calculating electronic tunnel currents in networks of disordered irregularly shaped nanoparticles by mapping networks to arrays of parallel nonlinear resistors  

Energy Technology Data Exchange (ETDEWEB)

We have shown both theoretically and experimentally that tunnel currents in networks of disordered irregularly shaped nanoparticles (NPs) can be calculated by considering the networks as arrays of parallel nonlinear resistors. Each resistor is described by a one-dimensional or a two-dimensional array of equal size nanoparticles that the tunnel junction gaps between nanoparticles in each resistor is assumed to be equal. The number of tunnel junctions between two contact electrodes and the tunnel junction gaps between nanoparticles are found to be functions of Coulomb blockade energies. In addition, the tunnel barriers between nanoparticles were considered to be tilted at high voltages. Furthermore, the role of thermal expansion coefficient of the tunnel junction gaps on the tunnel current is taken into account. The model calculations fit very well to the experimental data of a network of disordered gold nanoparticles, a forest of multi-wall carbon nanotubes, and a network of few-layer graphene nanoplates over a wide temperature range (5-300?K) at low and high DC bias voltages (0.001?mV–50?V). Our investigations indicate, although electron cotunneling in networks of disordered irregularly shaped NPs may occur, non-Arrhenius behavior at low temperatures cannot be described by the cotunneling model due to size distribution in the networks and irregular shape of nanoparticles. Non-Arrhenius behavior of the samples at zero bias voltage limit was attributed to the disorder in the samples. Unlike the electron cotunneling model, we found that the crossover from Arrhenius to non-Arrhenius behavior occurs at two temperatures, one at a high temperature and the other at a low temperature.

Aghili Yajadda, Mir Massoud [CSIRO Manufacturing Flagship, P.O. Box 218, Lindfield NSW 2070 (Australia)

2014-10-21

189

Calculating electronic tunnel currents in networks of disordered irregularly shaped nanoparticles by mapping networks to arrays of parallel nonlinear resistors  

Science.gov (United States)

We have shown both theoretically and experimentally that tunnel currents in networks of disordered irregularly shaped nanoparticles (NPs) can be calculated by considering the networks as arrays of parallel nonlinear resistors. Each resistor is described by a one-dimensional or a two-dimensional array of equal size nanoparticles that the tunnel junction gaps between nanoparticles in each resistor is assumed to be equal. The number of tunnel junctions between two contact electrodes and the tunnel junction gaps between nanoparticles are found to be functions of Coulomb blockade energies. In addition, the tunnel barriers between nanoparticles were considered to be tilted at high voltages. Furthermore, the role of thermal expansion coefficient of the tunnel junction gaps on the tunnel current is taken into account. The model calculations fit very well to the experimental data of a network of disordered gold nanoparticles, a forest of multi-wall carbon nanotubes, and a network of few-layer graphene nanoplates over a wide temperature range (5-300 K) at low and high DC bias voltages (0.001 mV-50 V). Our investigations indicate, although electron cotunneling in networks of disordered irregularly shaped NPs may occur, non-Arrhenius behavior at low temperatures cannot be described by the cotunneling model due to size distribution in the networks and irregular shape of nanoparticles. Non-Arrhenius behavior of the samples at zero bias voltage limit was attributed to the disorder in the samples. Unlike the electron cotunneling model, we found that the crossover from Arrhenius to non-Arrhenius behavior occurs at two temperatures, one at a high temperature and the other at a low temperature.

Aghili Yajadda, Mir Massoud

2014-10-01

190

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.

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

2013-12-01

191

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

OpenAIRE

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

192

Dividir para reinar / Diviser pour régner / Divide and conquer / Divide y vencerás  

Scientific Electronic Library Online (English)

Full Text Available SciELO Portugal | Language: Portuguese Abstract in portuguese O objectivo deste artigo é apresentar brevemente a Sociofísica, uma disciplina que, nas últimas décadas, se tem vindo a desenvolver na fronteira entre a Física e as ciências sociais. Como ilustração da sua abordagem, iremos rever alguns modelos de formação de opinião, incidindo nas condições em que [...] uma sociedade é mais sensível à penetração de uma mensagem externa. Nomeadamente, iremos ver que é mais fácil uma mensagem ser consensualmente aceite numa sociedade caracterizada por conflitos - o que recorda a antiga máxima “dividir para reinar”. Concluiremos, sugerindo que a construção deste novo campo do saber requer uma colaboração entre sociólogos e físicos, que vá mais além de uma simples justaposição de conhecimentos. Abstract in spanish El objectivo de este trabajo es presentar brevemente la Sociofísica, una disciplina que en las últimas décadas se ha venido a desarrollar en la frontera entre la física y las ciencias sociales. Cómo ejemplo de su enfoque, se revisan algunos modelos de formación de opinión, centrándose en las condici [...] ones en que una sociedad es más sensible a la penetración de un mensaje externo. En particular, vemos que el mensaje es más fácilmente aceptado en una sociedad caracterizada por el conflicto, lo que nos acuerda el antiguo dicho latino, “divide y vencerás”. Concluimos sugiriendo que la construcción de este nuevo campo del conocimiento requiere una colaboración entre los sociólogos y físicos, que va más allá de una simple yuxtaposición de conocimientos. Abstract in english The aim of this paper is to briefly present Sociophysics, a discipline that in recent decades has been emerging on the borders between Physics and the Social Sciences. As an illustration of its approach, we will review some opinion formation models, focusing on the conditions under which a society i [...] s more sensitive to the penetration of an external message. In particular, we will see that it is easier for a message to be commonly accepted in a society characterized by conflicts - which recalls the old maxim “divide and conquer”. We conclude by suggesting that the construction of this new field of knowledge requires a union between sociologists and physicists that goes beyond a simple juxtaposition of knowledge.

Teresa Vaz, Martins; Raúl, Toral.

2012-06-01

193

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 ...

194

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 permeasuring 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

195

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

196

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

197

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

198

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 are further concerns that the digital divide is further widening because of the quantity and quality of access. Multivariate analysis reveals that Chinese youths are online for twice the duration of Malays and Indians. However, higher Internet usage may be a two-edged sword as higher Internet use are intertwined with higher risks and negative activities such as violent games, pornography, and gambling. The article also discusses various means to mitigate the risks of Internet usage.

Patrick C-H Soh

2012-12-01

199

Pulse swallowing frequency divider with low power and compact structure  

Science.gov (United States)

A pulse swallowing frequency divider with low power and compact structure is presented. One of the DFFs in the divided by 2/3 prescaler is controlled by the modulus control signal, and automatically powered off when it has no contribution to the operation of the prescaler. The DFFs in the program counter and the swallow counter are shared to compose a compact structure, which reduces the power consumption further. The proposed multi-modulus frequency divider was implemented in a standard 65 nm CMOS process with an area of 28 × 22 ?m2. The power consumption of the divider is 0.6 mW under 1.2 V supply voltage when operating at 988 MHz.

Haijun, Gao; Lingling, Sun; Chaobo, Cai; Haiting, Zhan

2012-11-01

200

Pulse swallowing frequency divider with low power and compact structure  

International Nuclear Information System (INIS)

A pulse swallowing frequency divider with low power and compact structure is presented. One of the DFFs in the divided by 2/3 prescaler is controlled by the modulus control signal, and automatically powered off when it has no contribution to the operation of the prescaler. The DFFs in the program counter and the swallow counter are shared to compose a compact structure, which reduces the power consumption further. The proposed multi-modulus frequency divider was implemented in a standard 65 nm CMOS process with an area of 28 × 22 ?m2. The power consumption of the divider is 0.6 mW under 1.2 V supply voltage when operating at 988 MHz. (semiconductor integrated circuits)

201

Divided attention: an undesirable difficulty in memory retention.  

Science.gov (United States)

How can we improve memory retention? A large body of research has suggested that difficulty encountered during learning, such as when practice sessions are distributed rather than massed, can enhance later memory performance (see R. A. Bjork & E. L. Bjork, 1992). Here, we investigated whether divided attention during retrieval practice can also constitute a desirable difficulty. Following two initial study phases and one test phase with Swahili-English word pairs (e.g., vuvi-snake), we manipulated whether items were tested again under full or divided attention. Two days later, participants were brought back for a final cued-recall test (e.g., vuvi-?). Across three experiments (combined N = 122), we found no evidence that dividing attention while practicing retrieval enhances memory retention. This finding raises the question of why many types of difficulty during practice do improve long-term retention, but dividing attention does not. PMID:23690275

Gaspelin, Nicholas; Ruthruff, Eric; Pashler, Harold

2013-10-01

202

Annan warns of 'content divide' between rich and poor  

CERN Multimedia

"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

203

Crossing the Phantom Divide: Dark Energy Internal Degrees of Freedom  

OpenAIRE

Dark energy constraints have forced viable alternatives that differ substantially from a cosmological constant Lambda to have an equation of state w that evolves across the phantom divide set by Lambda. Naively, crossing this divide makes the dark energy gravitationally unstable, a problem that is typically finessed by unphysically ignoring the perturbations. While this procedure does not affect constraints near the favored cosmological constant model it can artificially enh...

Hu, Wayne

2004-01-01

204

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

OpenAIRE

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

205

Giant Eustachian Valve: with Echocardiographic Appearance of Divided Right Atrium  

OpenAIRE

The eustachian valve is an embryologic remnant of the valve of the inferior vena cava. It may be prominent in some individuals, but the echocardiographic appearance of a divided right atrium, as the consequence of a large eustachian valve, is extremely rare. Herein we describe an unusual giant eustachian valve with an echocardiographic appearance of a septal structure dividing the right atrium into 2 separate chambers. This abnormality should be differentiated from cor triatriatum dexter, a v...

Yavuz, Turhan; Nazli, Cem; Kinay, Ozan; Kutsal, Ali

2002-01-01

206

Decision support system to divide a large network into suitable District Metered Areas.  

Science.gov (United States)

This paper presents a new approach to divide large Water Distribution Networks (WDN) into suitable District Metered Areas (DMAs). It uses a hydraulic simulator and two operational models to identify the optimal number of DMAs, their entry points and boundary valves, and the network reinforcement/replacement needs throughout the project plan. The first model divides the WDN into suitable DMAs based on graph theory concepts and some user-defined criteria. The second model uses a simulated annealing algorithm to identify the optimal number and location of entry points and boundary valves, and the pipes reinforcement/replacement, necessary to meet the velocity and pressure requirements. The objective function is the difference between the economic benefits in terms of water loss reduction (arising from the average pressure reduction) and the cost of implementing the DMAs. To illustrate the proposed methodology, the results from a hypothetical case study are presented and discussed. PMID:22508131

Gomes, Ricardo; Marques, Alfeu Sá; Sousa, Joaquim

2012-01-01

207

Water  

SCPinfonet

...gr Interests: surface hydrology; water resources management and engineering; climate change impacts on hydrology and water resources; extreme hydrological events (...edu Interests: surface water/groundwater interactions; stable isotope hydrology; human impacts on water resources; wastewater; environmental geology * Section 'Groundwater' ...edu Interests: watershed hydrology; coastal hydrology; erosion and sediment transport; water quality; GIS and RS applications in water resources *...WF_ID=126 Interests: hydrology; vadose zone; soil physics; scaling; terrain; soil water; watershed modeling; global change Dr....

208

Internal resistor of multi-functional tunnel barrier for selectivity and switching uniformity in resistive random access memory  

Science.gov (United States)

In this research, we analyzed the multi-functional role of a tunnel barrier that can be integrated in devices. This tunnel barrier, acting as an internal resistor, changes its resistance with applied bias. Therefore, the current flow in the devices can be controlled by a tunneling mechanism that modifies the tunnel barrier thickness for non-linearity and switching uniformity of devices. When a device is in a low-resistance state, the tunnel barrier controls the current behavior of the device because most of the bias is applied to the tunnel barrier owing to its higher resistance. Furthermore, the tunnel barrier induces uniform filament formation during set operation with the tunnel barrier controlling the current flow.

Lee, Sangheon; Woo, Jiyong; Lee, Daeseok; Cha, Euijun; Hwang, Hyunsang

2014-07-01

209

Effects of finite system-size and finite inhomogeneity on the conductivity of broadly distributed resistor networks  

International Nuclear Information System (INIS)

Monte Carlo simulation is used to investigate the critical path calculation of the conductivity of a random resistor network that has a logarithmically broad distribution of bond conductances. It has been argued that in three dimensions the conductivity prefactor exponent y is equal to the percolation correlation length exponent ?, but past numerical computations have always found y

210

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

International Nuclear Information System (INIS)

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 Nparallel 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 10-7Pam3s-1m-2 within the maximum module temperature of ?100degC. This report describes the experimental and analytical results of a new lower hybrid (LH) antenna module using the poloidal power divider. (author)

211

Dividing cells regulate their lipid composition and localization.  

Science.gov (United States)

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. PMID:24462247

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

2014-01-30

212

Analysis and Simulation of a Photonic Crystal Power Divider  

Directory of Open Access Journals (Sweden)

Full Text Available In this research, the properties of a power divider that composed of two dimensional (2-D Photonic Crystals (PC have been analyzed. There is a large photonic band gap in transmission spectrum of the 2-D photonic crystal and by introducing a defect in the structure, some modes appear in it and propagate in the line defect waveguide. The PC power divider consists of a y-shaped line defect. The defect can be created by changing the size or removing the triangular PC defect rods. We have used an effective numerical method based on the Finite-Difference Time-Domain (FDTD scheme to compute the evolution of the electric and magnetic fields in the structure. We have demonstrated the electric field evolution and calculated the insertion loss, isolation and coupling factors of the PC power divider.

N. Nozhat

2007-01-01

213

Dividing annular/two-phase flow in horizontal T-junctions  

Science.gov (United States)

The results of an experimental and analytical investigation of the separation phenomenon in dividing annular two-phase flow are presented Detailed experiments have been carried out with a steam-water loop to isolate the effect of flow split, inlet quality, inlet mass flux, and branch diameter on the phase and pressure distribution characteristics in horizontal T-junctions. Through the set of measurements made in the experimental program, the phase separation and pressure distribution characteristics were shown to be strongly interdependent. Based on these measurements, a physical model describing the phase separation mechanism is presented. This physical model is then developed mathematically. A model to predict the dividing flow characteristics for annular flow in a T-junction is proposed consisting of mixture and vapor phase continuity equations, two pressure change correlations, and a closure relationship. The pressure change from the inlet through the run of the T is modeled by way of a balance of axial momentum at the junction based on a separated flow assumption. The branch pressure change is modeled using a balance of mechanical energy for the branching flow consisting of reversible and irreversible components. In the development of the branch model, a new equivalent inlet density for the branching flow (rho(sub 1)*) and a two-phase multiplier (Phi*) are defined. The closure relationship links the phase separation characteristics with the junction pressure changes. It involves a balance between pressure and inertia forces within the junction volume defining a dividing surface for each phase between the run and branch flows. The degree of phase redistribution is then determined using a well defined inlet flow distribution. The model is capable of predicting the experimentally observed phase separation characteristics from three independent studies of annular/steam-water and air-water flow in dividing T-junctions.

Ballyk, John David

1993-01-01

214

Analysis and Simulation of a Photonic Crystal Power Divider  

OpenAIRE

In this research, the properties of a power divider that composed of two dimensional (2-D) Photonic Crystals (PC) have been analyzed. There is a large photonic band gap in transmission spectrum of the 2-D photonic crystal and by introducing a defect in the structure, some modes appear in it and propagate in the line defect waveguide. The PC power divider consists of a y-shaped line defect. The defect can be created by changing the size or removing the triangular PC defect rods. We have used a...

Nozhat, N.; Granpayeh, N.

2007-01-01

215

Divided attention in young drivers under the influence of alcohol  

OpenAIRE

Aim: The present research evaluates driving impairment linked to two crashes factors, divided attention task and alcohol, and determines whether it is higher for novice drivers than for experienced drivers. Method: Novice and experienced drivers participated in three experimental sessions in which blood alcohol concentrations (BACs) were 0.0 g/L, 0.2 g/L and 0.5 g/L. They performed a divided attention task with a main task of car-following task and an additional task of number parity identifi...

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

2014-01-01

216

Google and the digital divide the bias of online knowledge  

CERN Document Server

Beneficial to scholars and students in the fields of media and communication, politics and technology, this book outlines the significant role of search engines in general and Google in particular in widening the digital divide between individuals, organisations and states. It uses innovative methods and research approaches to assess and illustrate the digital divide by comparing the popular search queries in Google and Yahoo in different countries as well as analysing the various biases in Google News and Google Earth. The different studies developed and presented in this book provide various

Segev, Elad

2010-01-01

217

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

218

Digital Divide among Youth: Socio-Cultural Factors and Implications  

Science.gov (United States)

Purpose: This paper aims to examine socio-cultural differences in internet use (Digital Divide) among 14-year-old Austrian pupils, in particular usage scenarios and research competences. It is based on a paper presented at the International Association for the Development of the Information Society e-Society conference, 10-13 March 2011, Spain…

Parycek, Peter; Sachs, Michael; Schossbock, Judith

2011-01-01

219

Journalism Students, Web 2.0 and the Digital Divide  

Science.gov (United States)

The purpose of this study was to find out if students were utilizing Web 2.0 applications. Since the applications in question are often employed by the media industry, the study aspired to find out if students majoring in mass communication and journalism utilized the applications more often than other students. The "digital divide" is a term used…

Green, Mary Elizabeth

2009-01-01

220

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.

National Science Foundation

221

The Learning Computer: Low Bandwidth Tool that Bridges Digital Divide  

Science.gov (United States)

This article reports on a project that explores strategies for narrowing the digital divide by providing a practicable e-learning option for the millions living outside the ambit of high performance computing and communication technology. The concept is introduced of a "learning computer," a low bandwidth tool that provides a simplified,…

Johnson, Russell; Kemp, Elizabeth; Kemp, Ray; Blakey, Peter

2007-01-01

222

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

223

Divide-And-Conquer Computation of Cylindrical Algebraic Decomposition  

OpenAIRE

We present a divide-and-conquer version of the Cylindrical Algebraic Decomposition (CAD) algorithm. The algorithm represents the input as a Boolean combination of subformulas, computes cylindrical algebraic decompositions of solution sets of the subformulas, and combines the results. We propose a graph-based heuristic to find a suitable partitioning of the input and present empirical comparison with direct CAD computation.

Strzebonski, Adam

2014-01-01

224

Hybrid songbirds employ intermediate routes in a migratory divide.  

Science.gov (United States)

Migratory divides are contact zones between populations that use different routes to navigate around unsuitable areas on seasonal migration. Hybrids in divides have been predicted to employ intermediate and potentially inferior routes. We provide the first direct test of this hypothesis, using light-level geolocators to track birds breeding in a hybrid zone between Swainson's thrushes in western Canada. Compared to parental forms, hybrids exhibited increased variability in their migratory routes, with some using intermediate routes that crossed arid and mountainous regions, and some using the same routes as one parental group on fall migration and the other on spring migration. Hybrids also tended to use geographically intermediate wintering sites. Analysis of genetic variation across the hybrid zone suggests moderately strong selection against hybrids. These results indicate that seasonal migratory behaviour might be a source of selection against hybrids, supporting a possible role for migration in speciation. PMID:25040456

Delmore, Kira E; Irwin, Darren E

2014-10-01

225

Handheld Computers: No Child Left Behind's (NCLB's Digital Divide Equalizers?  

Directory of Open Access Journals (Sweden)

Full Text Available The technology goals relating to The No Child Left Behind (NCLB Act of 2001 recommend that teachers provide equitable learning opportunities that optimize learning and prepare students to perform efficiently and effectively on standardized tests. Handheld computers can be very useful classroom management tools for providing technological equity and bridging the digital divide. As part of an Ohio Board of Regents Technology initiative, university teacher educators were trained in the use of handheld computers. The participants discussed and/or demonstrated how the handheld computer software, the scientific probes on board, the cameras, and portable keyboards can be used with their preservice teachers to acquaint them with ways of bridging the digital divide.

Doris G. Johnson

2005-09-01

226

Beyond artificial intelligence the disappearing human-machine divide  

CERN Document Server

This book is an edited collection of chapters based on the papers presented at the conference “Beyond AI: Artificial Dreams” held in Pilsen in November 2012. The aim of the conference was to question deep-rooted ideas of artificial intelligence and cast critical reflection on methods standing at its foundations.  Artificial Dreams epitomize our controversial quest for non-biological intelligence, and therefore the contributors of this book tried to fully exploit such a controversy in their respective chapters, which resulted in an interdisciplinary dialogue between experts from engineering, natural sciences and humanities.   While pursuing the Artificial Dreams, it has become clear that it is still more and more difficult to draw a clear divide between human and machine. And therefore this book tries to portrait such an image of what lies beyond artificial intelligence: we can see the disappearing human-machine divide, a very important phenomenon of nowadays technological society, the phenomenon which i...

Zackova, Eva; Kelemen, Jozef

2015-01-01

227

A Divide-and-Conquer Strategy for Parsing  

CERN Document Server

In this paper, we propose a novel strategy which is designed to enhance the accuracy of the parser by simplifying complex sentences before parsing. This approach involves the separate parsing of the constituent sub-sentences within a complex sentence. To achieve that, the divide-and-conquer strategy first disambiguates the roles of the link words in the sentence and segments the sentence based on these roles. The separate parse trees of the segmented sub-sentences and the noun phrases within them are then synthesized to form the final parse. To evaluate the effects of this strategy on parsing, we compare the original performance of a dependency parser with the performance when it is enhanced with the divide-and-conquer strategy. When tested on 600 sentences of the IPSM'95 data sets, the enhanced parser saw a considerable error reduction of 21.2% in its accuracy.

Shiuan, P L; Shiuan, Peh Li; Ann, Christopher Ting Hian

1996-01-01

228

Religion & Public Life: A Faith-Based Partisan Divide  

Science.gov (United States)

There was a great deal of discussion during the 2004 US presidential election about the so-called "faith-based" partisan divide. This insightful publication from the Pew Forum on Religion & Public Life takes a closer look at this divide in its 18-pages and provides a number of observations. The report begins by noting that Americans who regularly attend worship services and hold traditional religious views increasingly vote Republican, while those who are less connected to religious institutions tend to vote Democratic. Drawing on a number of polls and other surveys, the report also looks at other galvanizing issues such as opposition to gay marriage and attitudes towards stem cell research. The report also offers some interesting tables that look at how persons holding a variety of religious beliefs feel about the role of government and corporate welfare.

229

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

230

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

231

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

232

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

233

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

234

Is the digital divide between young and elderly people increasing?  

OpenAIRE

Elderly people still play a minor role in research on information needs and usage patterns of Internet users. Online research and advocacy groups look optimistically at the (economic and social) potential of the active and technology–skilled elderly; other approaches dealing with the social appropriation of technology see obstacles and stress the dangers of an increasing digital divide between generations. Our objective is to refer to taken for granted normative assumptions of the digital d...

Paul, Gerd; Stegbauer, Christian

2005-01-01

235

The 'Digital Divide' Among Financially Disadvantaged Families in Australia  

OpenAIRE

Despite figures suggesting that Australia is a high consumer of information and communication technologies (ICT), it is well documented that the pattern of this consumption is not spread evenly across the population; a 'digital divide' exists. In general, research suggests that people from higher socioeconomic backgrounds have greater access to ICT compared to those from lower socioeconomic backgrounds. A less well-researched area is the factors that may influence ICT access and usage within ...

Mclaren, Jennifer; Zappala, Gianni

2002-01-01

236

Use of previously divided latissimus dorsi muscle for bronchopleural fistula.  

Science.gov (United States)

Management of postpneumonectomy bronchopleural fistula remains a major challenge for thoracic surgeons. Successful closure of a postpneumonectomy bronchopleural fistula was performed in a 60-year-old man, using a flap made by a combination of serratus anterior and latissimus dorsi muscle which had been divided during the pneumonectomy operation. The flap was prepared on the presence of a dependable collateral serratus anterior branch to the lateral thoracic artery, which provides retrograde flow to the latissimus dorsi muscle. PMID:25107892

Kaplan, Tevfik; Kaya, Basar; Kazbek, Baturay Kansu; Kocer, Bulent; Han, Serdar; Yormuk, Erdem

2014-08-01

237

Spectral Clustering for Divide-and-Conquer Graph Matching  

OpenAIRE

We present a parallelized bijective graph matching algorithm that leverages seeds and is designed to match very large graphs. Our algorithm combines spectral graph embedding with existing state-of-the-art seeded graph matching procedures. We justify our approach by proving that modestly correlated, large stochastic block model random graphs are correctly matched utilizing very few seeds through our divide-and-conquer procedure.

Lyzinski, Vince; Sussman, Daniel L.; Fishkind, Donniell E.; Pao, Henry; Chen, Li; Vogelstein, Joshua T.; Park, Youngser; Priebe, Carey E.

2013-01-01

238

BRIDGING THE KNOWLEDGE DIVIDE Educational Technology for Development  

OpenAIRE

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 ...

Reviewed by Ozlem OZAN,

2009-01-01

239

A Divide-and-Conquer Strategy for Parsing  

OpenAIRE

In this paper, we propose a novel strategy which is designed to enhance the accuracy of the parser by simplifying complex sentences before parsing. This approach involves the separate parsing of the constituent sub-sentences within a complex sentence. To achieve that, the divide-and-conquer strategy first disambiguates the roles of the link words in the sentence and segments the sentence based on these roles. The separate parse trees of the segmented sub-sentences and the no...

Shiuan, Peh Li; Ann, Christopher Ting Hian

1996-01-01

240

The reansmission characteristcs of capacitive voltage divider with long cables  

International Nuclear Information System (INIS)

The transmission characteristics of the capacitive voltage divider with long cables in Z3 = Z0, Z4 = ? is studied. The analytic resolution and its difference form for Uin(s) = G(s)-1U0(s) in the time domain are obtained. These resolutions can be used to reconstruct the input waveforms. The quantitative relations between waveform distortion and the measurement system are given

241

Preferences for Employment Protection and the Insider-Outsider Divide  

OpenAIRE

Insider-outsider theory suggests that in dual labour markets two groups have opposing preferences regarding protection against dismissals: insiders defend employment protection, because it increases their rents. Outsiders see it as a mobility barrier and demand deregulation. Similar divides are expected for unemployment benefits: as insiders and outsiders have diverging unemployment risks, they should demand different levels of protection. Although these views are influential in the political...

Guillaud, Elvire; Marx, Paul

2013-01-01

242

THE DIGITAL DIVIDE: ICT DEVELOPMENT INDICES IN MEXICO  

Directory of Open Access Journals (Sweden)

Full Text Available The integration of Information and Communication Technologies (ICTs to the manufacturing sector enables to reduce production, management and marketing costs, allowing achieve higher levels of competitiveness. In the social area, ICTs are tools of inclusion improving the provision of education, health and government services, as well as expanding its coverage area of these services. To achieve these benefits it is required a proper incorporation and adaptation of ICTs in the social area, as well as, the development of required ICT services, properly. In this work, we analyze the role of the digital divide in the information society, as ground for social exclusion in the use of ICT in Mexico. Afterwards, the behavior of the digital divide is analyzed, with its different dimensions through time, also describing the penetration and development levels of ICT. Moreover, the case of study of university students enrolled in Information Technology careers is discussed in order to determine the existence of a digital divide and its parameters. Finally, a diagnosis about the growth of the Internet and mobile telephony services in Mexico is carried out, considering the prevailing world economic situation.

Edgar TELLO-LEAL

2012-01-01

243

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.

244

76 FR 22075 - Divide Ranger District, Rio Grande National Forest; CO; Black Mesa Vegetation Management Project  

Science.gov (United States)

...Service Divide Ranger District, Rio Grande National Forest; CO; Black Mesa...SUMMARY: The Divide Ranger District, Rio Grande National Forest, proposes to salvage...to comments-rocky-mountain-rio-grande-divide@fs.fed.us, or...

2011-04-20

245

Femtosecond fiber chirped and divided pulse amplification system  

OpenAIRE

We implement both chirped pulse amplification and divided pulse amplification in the same femtosecond fiber amplifier setup. This scheme allows an equivalent stretched pulse duration of 2.4 ns in a compact tabletop system. The generation of 77 W of compressed average power at 4.8 MHz, together with 320 fs and 430 ?J pulses at a repetition rate of 96 kHz, is demonstrated using a distributed mode-filtering, rod-type, ytterbium-doped fiber. Limitations in the temporal recombining efficiency due...

Zaouter, Yoann; Guichard, Florent; Daniault, Louis; Hanna, Marc; Morin, Franck; Ho?nninger, Clemens; Mottay, Eric; Druon, Fre?de?ric; Georges, Patrick

2013-01-01

246

Digital Television, Convergence, and the Public: Another Digital Divide?  

Directory of Open Access Journals (Sweden)

Full Text Available While 85 percent of Americans pay to receive television signals through satellite or cable companies, 15 percent still receive their television using over-the-air signals. With the elminination of analog television signals, the 15 percent of households have had to make significant changes in their viewing technology. These households tend to be elderly, poor, minority and rural. Signal coverage areas will be cut back, since government assumed a viewer would have an antenna on a 30 foot pole. Few do, and governmental programs delibertely hid this engineering fact. It is argued that digitalism has neglected the public use of the airways and created yet one more digital divide.

Jason Smith

2009-06-01

247

Recent Asteriod Lightcurve Studies at the Palmer Divide Observatory  

Science.gov (United States)

Finding the period and amplitude of asteroid lightcurves has been the main objective at the Palmer Divide Observatory since 1999. Since that time, more than 230 lightcurves have been measured, the majority of them having been produced in the last three years. In the last two years, special consideration has been given to the Hungaria group as well as potential binary asteroids. The latter effort has been in cooperation with the Binary Asteroids Survey conducted by Petr Pravec of Ondrejov Observatory. This report details recent results and their implications in terms of solar system evolution.

Warner, B. D.

2006-05-01

248

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

249

Nanotechnology Divides: Development Indicators and Thai Construction Industry  

Science.gov (United States)

Nanotechnology and disparity between developed and developing nations could increase the gap of global development while it also affects to construction industry where workers have potentially exposed to nanomaterials application. This research examined the influence of development indicators as demographic, social and economic factors on nanotechnology policy among 250 nations. Results revealed that 68.2% of developed countries have policy on nanotechnology while only 18% of developing countries have such a policy. Fertility and mortality declining with the increasing of literacy, urbanization and energy consumption provide significant positive effect on nanotechnology divides. Furthermore, results pointed out the existing gap of development between developed and developing worlds.

Kitisriworaphan, T.; Sawangdee, Y.

250

Tamil Nadu and the Diagonal Divide in Sex Ratios  

OpenAIRE

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

251

The Digital Divide: How Wide and How Deep?  

Directory of Open Access Journals (Sweden)

Full Text Available The complexity of the issues that make up the digital divide problem is better understood today. It is no longer sufficient to see it simply as a disparity of access to computer technology. Rather, there is recognition that having meaningful support for using the technology is also an essential ingredient for getting online. The digital divide is a global problem, but even in the technology rich United States the situation is troubling. Recent studies have shown that within the United States, public libraries play a key role in helping the digitally disadvantaged get connected to the Internet and learn how to use it to serve their needs. As more individuals are connected online, those who are not, however, are increasingly in danger for becoming more marginalized within society. Health care professionals need to be aware that they may well be working with individuals who are increasingly outside of the mainstream of the digital revolution and who cannot take advantage of Internet resources that could positively impact their health.

Barbara F. Schloman

2004-05-01

252

Future oscillations around phantom divide in f(R) gravity  

International Nuclear Information System (INIS)

It is known that scalar-tensor theory of gravity admits regular crossing of the phantom divide line wDE = ?1 for dark energy, and existing viable models of present dark energy for its particular case — f(R) gravity — possess one such crossing in the recent past, after the end of the matter dominated stage. It was recently noted that during the future evolution of these models the dark energy equation of state wDE may oscillate with an arbitrary number of phantom divide crossings. In this paper we prove that the number of crossings can be infinite, present an analytical condition for the existence of this effect and investigate it numerically. With the increase of the present mass of the scalaron (a scalar particle appearing in f(R) gravity) beyond the boundary of the appearance of such oscillations, their amplitude is shown to decrease very fast. As a result, the effect quickly becomes small and its beginning is shifted to the remote future

253

Digital Divide between Teachers and Students in Urban Bangladesh  

DEFF Research Database (Denmark)

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, the capital of Bangladesh. About 75 students enrolled in probability and statistics course of Independent University, Bangladesh (IUB) in autumn 2009 participated in conducting survey activities. Total 33 academic institutes were south for approval and 11 could be surveyed before the Christmas and annual recess. Responses from 6 other academics institutes were collected from the personal networks of students. A questionnaire was developed based on initial semi-structured interview with randomly selected students from these academic institutions. The 41-question questionnaire was developed to study the usage of computer, internet, mobile and other handheld devices, radio, television and CD/DVD players. A slightly different questionnaire was developed for teachers. 965 students and 185 teachers participated in the survey. Among student respondents 37% were from English Medium and 63% from Bangla medium institutions. From class VI –XII, the survey group represent the secondary and higher secondary education level in Bangladesh. Male respondents were 53% and female 43%, remaining are missing. Responses collected using paper-based questionnaires were put on a learning management system’s (LMS) questionnaire survey module. Irrespective of type of ICT device higher percentage of English medium students ‘own’ and know ‘how to use’ compared to Bangla medium students. Significantly higher percentage of students can use and own desktop, laptop, cellphone, iPOD and MP3 player. While teachers mostly use computers for work (73%), study (45%) and listening music (34%), students use for playing games (63%), listening musing (62%) and study (44%). 69% teachers and 66% students use social networking sites. Top three online activities for students are music (53%), games (47%) and chat (42%), for teachers these are study (55%), chat (40%) and music (33%). Students use more mobile features than teachers. Interestingly 59% teachers and 61% students have more than one SIM card. More than 50% of students and teachers use mobile for listening radio. 55% or more teachers and 67% or more students ‘own’ a desktop. 90% or more teachers and 74% or more students ‘know how to use’ desktop computer. Further study is required to gain insight into digital divide and associated reasons in four different educations systems in Bangladesh.

Khalid, Md. Saifuddin

2011-01-01

254

Universal Service in a Broader Perspective: The European Digital Divide  

Directory of Open Access Journals (Sweden)

Full Text Available Ensuring universal service is a top objective in many countries in order that all the citizens can have access basic communications services. Although the ICT equipment in households and its usage by individuals are essential prerequisites for benefiting from ICTs, the situation in the European Union is far from uniform. This article provides a description of the European information society development scenario using the values reached by the member states in a set of indicators selected for measuring said progress in households. Two tools are used for providing a broader perspective of the digital divide: a composite index and the cluster analysis. Below, a study is provided on what variables are relevant for interpreting the situation that is presented.

Maria Concepcion GARCIA-JIMENEZ

2009-01-01

255

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

256

Divide et Impera?: Western Engagement in the Middle East  

Directory of Open Access Journals (Sweden)

Full Text Available One, important, reason driving recent instability in the Middle East is the influence of Western powers on local actors. In the first half of the 20th century the UK and France held significant sway; during the Cold War the US and USSR were dominant. After the Cold War, the US emerged as the sole, dominating foreign actor in the region. What commonality was shared among all penetrating powers? The strategy of divide and rule was widely deployed. Such a policy was introduced by various means: supporting segments of local populations (especially Arab Christians, polarising local communities against each other and through direct settler activities. This policy was efficient in the short-term but proved destabilising in the long-term. This work takes a critical, birds-eye view at the evolution of engagement in the region and offers insights into the problems produced by such approaches as well as the net benefactors and losers.

Marek ?ejka

2012-12-01

257

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)

258

The effects of age and divided attention on spontaneous recognition.  

Science.gov (United States)

Studies of recognition typically involve tests in which the participant's memory for a stimulus is directly questioned. There are occasions however, in which memory occurs more spontaneously (e.g., an acquaintance seeming familiar out of context). Spontaneous recognition was investigated in a novel paradigm involving study of pictures and words followed by recognition judgments on stimuli with an old or new word superimposed over an old or new picture. Participants were instructed to make their recognition decision on either the picture or word and to ignore the distracting stimulus. Spontaneous recognition was measured as the influence of old vs. new distracters on target recognition. Across two experiments, older adults and younger adults placed under divided-attention showed a greater tendency to spontaneously recognize old distracters as compared to full-attention younger adults. The occurrence of spontaneous recognition is discussed in relation to ability to constrain retrieval to goal-relevant information. PMID:21264592

Anderson, Benjamin A; Jacoby, Larry L; Thomas, Ruthann C; Balota, David A

2011-05-01

259

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 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

260

Spike sorting for polytrodes: a divide and conquer approach  

Directory of Open Access Journals (Sweden)

Full Text Available In order to determine patterns of neural activity, spike signals recorded by extracellular electrodes have to be clustered (sorted with the aim of ensuring that each cluster represents all the spikes generated by an individual neuron. Many methods for spike sorting have been proposed but few are easily applicable to recordings from polytrodes which may have 16 or more recording sites. As with tetrodes, these are spaced sufficiently closely that signals from single neurons will usually be recorded on several adjacent sites. Although this offers a better chance of distinguishing neurons with similarly shaped spikes, sorting is difficult in such cases because of the high dimensionality of the space in which the signals must be classified. This report details a method for spike sorting based on a divide and conquer approach. Clusters are initially formed by assigning each event to the channel on which it is largest. Each channel-based cluster is then sub-divided into as many distinct clusters as possible. These are then recombined on the basis of pairwise tests into a final set of clusters. Pairwise tests are also performed to establish how distinct each cluster is from the others. A modified gradient ascent clustering (GAC algorithm is used to do the clustering. The method can sort spikes with minimal user input in times comparable to real time for recordings lasting up to 45 minutes. Our results illustrate some of the difficulties inherent in spike sorting, including changes in spike shape over time. We show that some physiologically distinct units may have very similar spike shapes. We show that RMS measures of spike shape similarity are not sensitive enough to discriminate clusters that can otherwise be separated by principal components analysis. Hence spike sorting based on least-squares matching to templates may be unreliable. Our methods should be applicable to tetrodes and scaleable to larger multi-electrode arrays (MEAs.

Nicholas V. Swindale

2014-02-01

261

Platonic Relationships Among Resistors  

Science.gov (United States)

Calculating the effective resistance of an electrical network is a common problem in introductory physics courses. Such calculations are typically restricted to two-dimensional networks, though even such networks can become increasingly complex, leading to several studies on their properties.1,2 Furthermore, several authors3-6 have used advanced techniques (graph theory, superposition of equipotential planes, and Green's functions) to perform theoretical calculations for three-dimensional networks, particularly focusing on the five Platonic solids due to their symmetry. However, these techniques are typically beyond the mathematical level of an undergraduate or advanced high school student. In this article, we outline techniques for analyzing these systems that are accessible to an introductory physics student. We also test these results experimentally using standard laboratory equipment.

Allen, Bradley; Liu, Tongtian

2015-02-01

262

Development in Sub-Saharan Africa: Overcoming the Digital Divide  

Directory of Open Access Journals (Sweden)

Full Text Available In an increasingly digitalized world economy, there exists a digital gap between Sub-Saharan Africa and the rest of the world that translates into economic marginalization of the African region. Consequently, the following phases of development are crucial for the region: (1 the phase of massive digitalization during which the digital divide is bridged and (2 the phase of information and knowledge management in which information is systematically converted into knowledge and the latter into innovative-sustainable development. Information for conversion into knowledge is supplied by the first phase. The second phase is therefore existence dependent on the first. Therefore, the attainment of digitalized state is primary-sine qua non. The envisaged digitalized state can be actualized and consolidated with a combination of: (a curriculum in computer education consisting of computer taxonomy, networking and ICTS in general for secondary and tertiary institutions but also aptly adoptable for informal groups and (b establishment of multipurpose telecentres in rural areas and a diffusion of networks in urban centres. Once a steady digitalized state evidenced by uninterrupted connectivity to the internet is attained, the second phase can be realized. Without steady supply of electricity, however, sustainable development and competitive edge may be hard to come by in a world of fierce competition.

Oyedokun Agbeja

2007-01-01

263

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 V1 and V2 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)

264

Informaticiens Sans Frontieres: Helping to bridge the Digital Divide  

CERN Document Server

ISF 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. ISF est né comme un club du CERN, en 2003, pendant le Sommet Mondiale de la Société de l'information à Genève. Aujourd'hui nous participons à plusieurs projets avec le but d'aider l'Afrique à reduire la Fracture Numérique, ou de fournir de la puissance de calcul (BOINC) à la recherche contre le Paludisme, ou en créant des GRIDs qui pourra...

CERN. Geneva

2009-01-01

265

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

266

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

267

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

International Nuclear Information System (INIS)

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)

268

On the development of a model for predicting phase separation phenomena in dividing two-phase flow  

International Nuclear Information System (INIS)

A model to predict the dividing flow characteristics for annular flow in a T-junction is proposed consisting of mixture and vapour phase continuity equations, two pressure change correlations and a closure relationship. The pressure change from the inlet through the run of the T is modelled by way of a balance of axial momentum at the junction based on a separated flow assumption. The branch pressure change is modelled using a balance of mechanical energy for the branching flow consisting of reversible and irreversible components. The closure relationship links the phase separation characteristics with the junction pressure changes. It involves a balance between pressure and inertia forces within the junction volume defining a dividing surface for each phase between the run and branch flows. The branch quality is then determined using a well-defined inlet flow distribution. The model is capable of predicting the experimentally observed phase separation characteristics from three independent studies of annular/steam-water and air-water flow in dividing T-junctions. (orig.)

269

Liquid-liquid extraction: An adsorption isotherm at divided interface?  

International Nuclear Information System (INIS)

We show that liquid-liquid extraction can be described as the equilibrium between two pseudo-phases of ions: the hydrated state in the water phase and the solvation state when the ions are adsorbed on an organized interface. The extractant is considered as a potential surface where the ions can adsorb. Unlike phenomenological binding 'constants', ion extraction/stripping can be seen as the sum of Langmuir isotherms. The number of aggregated extractants in one reverse micelle in the solvent is at least equal to or higher than the number of extracting molecules complexed at a given instant to the ion to be extracted. Considering extraction equilibrium as a sum of isotherms corresponding to the different states of aggregation of extractant molecule in the solvent, the resulting constant is representative of both the efficiency of the extraction and the structure of the solution. This is a first step toward the development of predictive models for the apparent distribution coefficients. (authors)

270

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

271

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

272

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

Energy Technology Data Exchange (ETDEWEB)

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{sup 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.

Shimojo, Fuyuki; Hattori, Shinnosuke [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States); Department of Physics, Kumamoto University, Kumamoto 860-8555 (Japan); Kalia, Rajiv K.; Mou, Weiwei; Nakano, Aiichiro; Nomura, Ken-ichi; Rajak, Pankaj; Vashishta, Priya [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States); Kunaseth, Manaschai [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States); National Nanotechnology Center, Pathumthani 12120 (Thailand); Ohmura, Satoshi [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States); Department of Physics, Kumamoto University, Kumamoto 860-8555 (Japan); Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Shimamura, Kohei [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States); Department of Physics, Kumamoto University, Kumamoto 860-8555 (Japan); Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395 (Japan)

2014-05-14

273

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

274

Effects of divided attention on swallowing in healthy participants.  

Science.gov (United States)

Swallowing impairments are treated mostly behaviorally. It is requisite to understand the relationship of cognition, specifically attention, with swallowing since so many swallowing impairments occur concomitantly with cognitive disorders. This study examined the hypothesis that attentional resources are required during swallowing. The approach involved a dual-task, reaction time (RT) paradigm in ten healthy, nonimpaired participants. Baseline measures were obtained of the duration of the anticipatory phase and of the oropharyngeal phase of swallowing and the RTs to nonword auditory stimuli. A dual-task then required participants to swallow 5 ml of water from an 8-oz. cup while listening for a target nonword presented auditorily during the anticipatory or the oropharyngeal phase. Target stimuli were randomized across baseline and dual-task trials. Duration of the anticipatory phase and of the oropharyngeal phase of swallowing and duration of the RT baseline trial and of the dual-task trial were determined. Results showed a statistically significant increase in speed of the anticipatory phase, relative to the oropharyngeal phase, for swallowing during the dual-task. RTs were slowed for both the anticipatory and the oropharyngeal phase during the dual-task, although neither of these was statistically significant. Clinical implications of these data suggest that disruptive stimuli in the environment to nonimpaired individuals may alter feeding but have little effect on the oropharyngeal swallow. PMID:21892783

Brodsky, Martin B; McNeil, Malcolm R; Martin-Harris, Bonnie; Palmer, Catherine V; Grayhack, Judith P; Abbott, Katherine Verdolini

2012-09-01

275

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  

OpenAIRE

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 d...

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

2010-01-01

276

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

OpenAIRE

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,...

Dewhurst, Stephen A.; Barry, Christopher; Swannell, Ellen R.; Holmes, Selina J.; Bathurst, Gemma J.

2007-01-01

277

75 FR 54085 - Divide Ranger District, Rio Grande National Forest; Colorado; Big Moose Vegetation Management...  

Science.gov (United States)

...OF AGRICULTURE Forest Service Divide Ranger District, Rio Grande National Forest; Colorado; Big Moose Vegetation Management Project AGENCY: Forest Service, Rio Grande National Forest, USDA. ACTION: Corrected Notice...

2010-09-03

278

From Digital Divides to Digital Inequality -- The Emerging Digital Inequality in the Norwegian Unitarian School  

Science.gov (United States)

This position paper highlights existing and emerging, prospective digital divides in Norwegian schools and asks whether we are now moving from traditional digital divides to digital inequality in our digitized society and schools. Despite very good technology density in Norwegian society and schools in general, there is the reason to pay attention…

Krumsvik, Rune J.

2008-01-01

279

Social Impact of the "Digital Divide" in a Central-Eastern European Country.  

Science.gov (United States)

Discusses the social impact of the digital divide in Central-Eastern European countries as well as between them and industrialized developed countries, based on experiences in Romania. Highlights include facts relating to digital divide worldwide; transition to a democratic and market-based economy and from socialism to capitalism; barriers to…

Dragulanescu, Nicolae-George

2002-01-01

280

The Divide between Diversity Training and Diversity Education: Integrating Best Practices  

Science.gov (United States)

The fields of diversity training and diversity education have developed in a disconnected manner. This divide ensures that each field advances slowly and with narrow focus. The authors argue here that the divide should be bridged with attention to the best practices that diversity training and diversity education offer. By integrating the best…

King, Eden B.; Gulick, Lisa M. V.; Avery, Derek R.

2010-01-01

281

Frequency key divider for synthesizer of operating frequencies in high-resolution nuclear magnetic resonance spectrometer  

International Nuclear Information System (INIS)

A switching divider for division of the frequency of harmonic waves in the microwave range up to 22 MHz is described; the divider ensures a division factor exceeding 20, a locking band of 10%, and a high spectral purity; it has small dimensions and is simple to fabricate

282

Progress in the development of an electronic nose using arrays of chemically sensitive carbon black-polymer resistors  

Science.gov (United States)

Response data were collected for a carbon black-polymer composite electronic nose array during exposure to homologous series of alkanes and alcohols. At a fixed partial pressure of odorant in the vapor phase, the mean response intensity of the electronic nose signals varied significantly for members of each series of odorants. However, the mean response intensity of the electronic nose detectors, and the response intensity of the most strongly-driven set of electronic nose detectors, was essentially constant for members of a chemically homologous odorant series when the concentration of each odorant in the gas phase was maintained at a constant fraction of the odorant's vapor pressure. Because the thermodynamic activity of an odorant at equilibrium in a sorbent phase is equal to the partial pressure of the odorant in the gas phase divided by the vapor pressure of the odorant, and because the activity coefficients are similar within these homologous series of odorants for sorption of the vapors into specific polymer films, the data imply that the trends in detector response can be understood based on the thermodynamic tendency to establish a relatively constant concentration of sorbed odorant into each of the polymeric films of the electronic nose at a constant fraction of the odorant's vapor pressure. This phenomenon provides a natural mechanism for enhanced sensitivity to low vapor pressure compounds, like TNT, in the presence of high vapor pressure analytes, such as diesel fuel. In a related study to evaluate the target recognition properties of the electronic nose, a statistical metric based on the magnitudes and standard deviations along Euclidean projections of clustered array response data, was utilized to facilitate an evaluation of the performance of detector arrays in various vapor classification tasks. This approach allowed quantification of the ability of a fourteen-element array of carbon black-insulating polymer composite chemiresistors to distinguish between members of a set of nineteen solvent vapors, some of which vary widely in chemical properties (e.g. methanol and benzene) and others of which are very similar (e.g. n-pentane and n-heptane). The data also facilitated evaluation of questions such as array performance as a function of the number of detectors in the system.

Doleman, Brett J.; Severin, Erik J.; Sanner, Robert D.; Lewis, Nathan S.

1998-09-01

283

Rare combination of bilateral divided atrial chambers and pulmonary vein stenosis with review of the literature.  

Science.gov (United States)

Introduction: The term cor triatriatum is used to describe a fibromuscular partition that divides an atrium into two compartments. It was first used by Borst in 1905, although the lesion had been described before by Church in 1868. Both described divided left atrial chamber (also referred to as cor triatriatum sinister). The incidence of the divided left atrial chamber among patients with congenital heart disease is reported at 0.1% and 0.4% in an autopsy study. Divided right atrial chamber - also referred to as cor triatriatum dexter - is even rarer to an extent that there is no reported incidence and only few hundred cases have been reported so far. A search through pubMed library revealed only 90 publications on humans, either under the term "dexter" or "dextrum". We would like to report a new association of bilateral divided atrial chambers and pulmonary vein stenosis, with a review of the literature. PMID:24933300

Al-Mousily, Faris; Baslaim, Ghassan; Kouatli, Amjad; Al-Ata, Jameel; Arfi, Amin M

2014-06-16

284

Research on Dividing Modeling of Female Suits Based on Cognitive Psychology  

Directory of Open Access Journals (Sweden)

Full Text Available According to apparel modeling aesthetics of consumers, in this paper, the detail modeling dividing lines of female suits were selected as subject. And with the evaluating indexes defined, the dividing modeling was classified and the control points of dividing lines were found. Then 90 images of women suits with different dividing modeling were drawn. And the experimental data of 64 students aged from 19 to 26 years old from Soochow University were collected by software named E-prime. At last, with data processing software called Excel and SPSS, the differences of evaluating indexes were analyzed and the best positions of control points were found. Thus, the best dividing modeling of women suits were obtained.

Gu Pin-Ying

2013-01-01

285

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 contenaterial with high silicate glass content

286

Divided left atrium (cor triatriatum) in the setting of common atrium.  

Science.gov (United States)

Cor triatriatum is commonly used to describe the congenital malformation in which an anomalous fibromuscular shelf divides the left atrium. We report the successful surgical repair of an extremely rare combination of divided left atrium, virtual absence of the interatrial septum, and anomalous right pulmonary venous connection in a 7 year-old girl. Preoperative transthoracic echocardiography could not detect the dividing left atrial shelf. In this report, we point out the limitations of transthoracic echocardiography in the diagnosis of atypical cases of so-called cor triatriatum and highlight errors in the scientific literature resulting from the variance in terminology ascribed to congenital division of the left atrium. PMID:22579903

Edwin, Frank; Gyan, Baffoe; Tettey, Mark; Aniteye, Ernest

2012-08-01

287

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

OpenAIRE

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

288

Illusory recollection in older adults and younger adults under divided attention.  

Science.gov (United States)

The authors investigated the effect of divided attention, study-list repetition, and age on recollection and familiarity. Older and younger adults under full attention and younger adults under divided attention at study viewed word lists highly associated with a single unstudied word (critical lure) once or three times, and subsequently performed a remember-know recognition test. Younger adults made fewer false remember responses to critical lures from repeated study lists, whereas younger adults under divided attention and older adults both showed an increase with repetition. Findings suggest older adults' susceptibility to illusory memories is related to a deficit in available attention during encoding. PMID:19290753

Skinner, Erin I; Fernandes, Myra A

2009-03-01

289

Defining and dividing the greater Caribbean: insights from the biogeography of shorefishes.  

Science.gov (United States)

The Greater Caribbean biogeographic region is the high-diversity heart of the Tropical West Atlantic, one of four global centers of tropical marine biodiversity. The traditional view of the Greater Caribbean is that it is limited to the Caribbean, West Indies, southwest Gulf of Mexico and tip of Florida, and that, due to its faunal homogeneity, lacks major provincial subdivisions. In this scenario the northern 2/3 of the Gulf of Mexico and southeastern USA represent a separate temperate, "Carolinian" biogeographic region. We completed a comprehensive re-assessment of the biogeography of the Greater Caribbean by comparing the distributions of 1,559 shorefish species within 45 sections of shelf waters of the Greater Caribbean and adjacent areas. This analysis shows that that the Greater Caribbean occupies a much larger area than usually thought, extending south to at least Guyana, and north to encompass the entire Carolinian area. Rather than being homogenous, the Greater Caribbean is divided into three major provinces, each with a distinctive, primarily tropical fauna: (1) a central, tropical province comprising the West Indies, Bermuda and Central America; (2) a southern, upwelling-affected province spanning the entire continental shelf of northern South America; and (iii) a northern, subtropical province that includes all of the Gulf of Mexico, Florida and southeastern USA. This three-province pattern holds for both reef- and soft bottom fishes, indicating a general response by demersal fishes to major variation in provincial shelf environments. Such environmental differences include latitudinal variation in sea temperature, availability of major habitats (coral reefs, soft bottom shorelines, and mangroves), and nutrient additions from upwelling areas and large rivers. The three-province arrangement of the Greater Caribbean broadly resembles and has a similar environmental basis to the provincial arrangement of its sister biogeographic region, the Tropical Eastern Pacific. PMID:25054225

Robertson, D Ross; Cramer, Katie L

2014-01-01

290

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

291

DCA: an efficient implementation of the divide-and-conquer approach to simultaneous multiple sequence alignment  

OpenAIRE

MOTIVATION: DCA is a new computer program for multiple sequence alignment which utilizes a 'divide-and-conquer' type of heuristic approach. AVAILABILITY: The algorithm is freely available from http://bibiserv.TechFak.Uni-Bielefeld.DE/dca/.

Stoye, Jens; Moulton, Vincent; Dress, Andreas

1997-01-01

292

Harmonic-suppressed quadrature-input frequency divider for OFDM systems  

International Nuclear Information System (INIS)

A fully balanced harmonic-suppressed quadrature-input frequency divider is proposed. The frequency divider improves the quadrature phase accuracy at the output by using both input I/Q signals. Compared with conventional dividers, the circuit achieves an output I/Q phase sequence that is independent of the input I/Q phase sequence. Moreover, the third harmonic is effectively suppressed by employing a double degeneration technique. The design is fabricated in TSMC 0.13-?m CMOS and operated at 1.2 V. While locked at 8.5 GHz, the proposed divider measures a maximum third harmonic rejection of 45 dB and a phase noise of ?124 dBc/Hz at a 10 MHz offset. The circuit achieves a locking range of 15% while consuming a total current of 4.5 mA. (semiconductor integrated circuits)

293

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

294

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.

295

Information Resources Column: "The Digital Divide: How Wide and How Deep?  

OpenAIRE

The complexity of the issues that make up the digital divide problem is better understood today. It is no longer sufficient to see it simply as a disparity of access to computer technology. Rather, there is recognition that having meaningful support for using the technology is also an essential ingredient for getting online. The digital divide is a global problem, but even in the technology rich United States the situation is troubling. Recent studies have shown that within the United States,...

Schloman, B.

2004-01-01

296

Implementation of high-speed fixed-point dividers on FPGA  

OpenAIRE

Study deals with implementations of fixed-point division modules based on different algorithms on basis of Xilinx FPGAs. We show that our implementation of the nonrestoring algorithm is significantly faster and smaller than the 32-bit IP Core "Pipelined Divider" from Xilinx. For example, the speed of the 32-bit designed module is almost 245 MHz vs. 193 MHz from Xilinx divider. Moreover, high-speed parameterized modules are designed to provide arbitrary precision of the fixed-point division, f...

Sorokin, Nikolai

2006-01-01

297

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

OpenAIRE

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

298

Orientation and three-dimensional organization of actin filaments in dividing cultured cells  

OpenAIRE

The current hypothesis of cytokinesis suggests that contractile forces in the cleavage furrow are generated by a circumferential band of actin filaments. However, relatively little is known about the global organization of actin filaments in dividing cells. To approach this problem we have used fluorescence-detected linear dichroism (FDLD) microscopy to measure filament orientation, and digital optical sectioning microscopy to perform three-dimensional reconstructions of dividing NRK cells st...

1993-01-01

299

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

300

Integrative tracking methods elucidate the evolutionary dynamics of a migratory divide.  

Science.gov (United States)

Migratory divides, the boundary between adjacent bird populations that migrate in different directions, are of considerable interest to evolutionary biologists because of their alleged role in speciation of migratory birds. However, the small size of many passerines has traditionally limited the tools available to track populations and as a result, restricted our ability to study how reproductive isolation might occur across a divide. Here, we integrate multiple approaches by using genetic, geolocator, and morphological data to investigate a migratory divide in hermit thrushes (Catharus guttatus). First, high genetic divergence between migratory groups indicates the divide is a region of secondary contact between historically isolated populations. Second, despite low sample sizes, geolocators reveal dramatic differences in overwintering locations and migratory distance of individuals from either side of the divide. Third, a diagnostic genetic marker that proved useful for tracking a key population suggests a likely intermediate nonbreeding location of birds from the hybrid zone. This finding, combined with lower return rates from this region, is consistent with comparatively lower fitness of hybrids, which is possibly due to this intermediate migration pattern. We discuss our results in the context of reproductive isolating mechanisms associated with migration patterns that have long been hypothesized to promote divergence across migratory divides. PMID:25535561

Alvarado, Allison H; Fuller, Trevon L; Smith, Thomas B

2014-09-01

301

Combined uranous nitrate production consisting of undivided electrolytic cell and divided electrolytic cell (Electrolysis ? Electrolytic cell)  

Energy Technology Data Exchange (ETDEWEB)

The electrochemical reduction of uranyl nitrate is a green, mild way to make uranous ions. Undivided electrolyzers whose maintenance is less but their conversion ratio and current efficiency are low, have been chosen. However, at the beginning of undivided electrolysis, high current efficiency can also be maintained. Divided electrolyzers' conversion ratio and current efficiency is much higher because the re-oxidation of uranous on anode is avoided, but their maintenance costs are more, because in radioactive environment the membrane has to be changed after several operations. In this paper, a combined method of uranous production is proposed which consists of 2 stages: undivided electrolysis (early stage) and divided electrolysis (late stage) to benefit from the advantages of both electrolysis modes. The performance of the combined method was tested. The results show that in combined mode, after 200 min long electrolysis (80 min undivided electrolysis and 120 min divided electrolysis), U(IV) yield can achieve 92.3% (500 ml feed, U 199 g/l, 72 cm{sup 2} cathode, 120 mA/cm{sup 2}). Compared with divided mode, about 1/3 working time in divided electrolyzer is reduced to achieve the same U(IV) yield. If 120 min long undivided electrolysis was taken, more than 1/2 working time can be reduced in divided electrolyzer, which means that about half of the maintenance cost can also be reduced. (authors)

Yuan, Zhongwei; Yan, Taihong; Zheng, Weifang; Li, Xiaodong; Yang, Hui; Xian, Liang [China Institute of Atomic Energy, P.O.Box 275-26, Beijing 102413 (China)

2013-07-01

302

Combined uranous nitrate production consisting of undivided electrolytic cell and divided electrolytic cell (Electrolysis ? Electrolytic cell)  

International Nuclear Information System (INIS)

The electrochemical reduction of uranyl nitrate is a green, mild way to make uranous ions. Undivided electrolyzers whose maintenance is less but their conversion ratio and current efficiency are low, have been chosen. However, at the beginning of undivided electrolysis, high current efficiency can also be maintained. Divided electrolyzers' conversion ratio and current efficiency is much higher because the re-oxidation of uranous on anode is avoided, but their maintenance costs are more, because in radioactive environment the membrane has to be changed after several operations. In this paper, a combined method of uranous production is proposed which consists of 2 stages: undivided electrolysis (early stage) and divided electrolysis (late stage) to benefit from the advantages of both electrolysis modes. The performance of the combined method was tested. The results show that in combined mode, after 200 min long electrolysis (80 min undivided electrolysis and 120 min divided electrolysis), U(IV) yield can achieve 92.3% (500 ml feed, U 199 g/l, 72 cm2 cathode, 120 mA/cm2). Compared with divided mode, about 1/3 working time in divided electrolyzer is reduced to achieve the same U(IV) yield. If 120 min long undivided electrolysis was taken, more than 1/2 working time can be reduced in divided electrolyzer, which means that about half of the maintenance cost can also be reduced. (authors)

303

Integrative tracking methods elucidate the evolutionary dynamics of a migratory divide  

Science.gov (United States)

Migratory divides, the boundary between adjacent bird populations that migrate in different directions, are of considerable interest to evolutionary biologists because of their alleged role in speciation of migratory birds. However, the small size of many passerines has traditionally limited the tools available to track populations and as a result, restricted our ability to study how reproductive isolation might occur across a divide. Here, we integrate multiple approaches by using genetic, geolocator, and morphological data to investigate a migratory divide in hermit thrushes (Catharus guttatus). First, high genetic divergence between migratory groups indicates the divide is a region of secondary contact between historically isolated populations. Second, despite low sample sizes, geolocators reveal dramatic differences in overwintering locations and migratory distance of individuals from either side of the divide. Third, a diagnostic genetic marker that proved useful for tracking a key population suggests a likely intermediate nonbreeding location of birds from the hybrid zone. This finding, combined with lower return rates from this region, is consistent with comparatively lower fitness of hybrids, which is possibly due to this intermediate migration pattern. We discuss our results in the context of reproductive isolating mechanisms associated with migration patterns that have long been hypothesized to promote divergence across migratory divides.

Alvarado, Allison H; Fuller, Trevon L; Smith, Thomas B

2014-01-01

304

Marketing mix of chosen Slovak mineral water  

OpenAIRE

Considering its small area, Slovakia abounds in many sources of mineral waters and a considerable amount of them can be used for the commercial utilization. STN 86 8000 divides mineral waters in the natural mineral waters, natural mineral table waters and the natural mineral healing waters. Natural mineral water is, after the present norm, in effect water, which rises from natural trapped sources. This type of water contains more than 1 gram of dissolved substances or 1 gram of dissolved CO 2...

Juhanová Silvia; Tometz Ladislav

2001-01-01

305

Temporal and Spatial Variability in Snow Accumulation at WAIS Divide over Recent Centuries  

Science.gov (United States)

Temporal and spatial variability in snow accumulation was evaluated using ice cores collected in 2000 (ITASE 00-1) and 2005 (WDC05A, WDC05Q) from the West Antarctic Ice Sheet Divide (WAIS Divide) project site. The ice cores were dated based on annual layer counting of multiple glaciochemical measurements resulting in mean annual accumulation rates of 0.200, 0.204, and 0.221 mweq yr-1 for WDC05A, WDC05Q, and ITASE 00-1, respectively. An analysis of variance of accumulation in the ice core array was used to determine the small scale spatial variability (SSV), allowing for quantification of uncertainty in an individual accumulation record. The spatial variability for the WAIS Divide project site was calculated to be 0.030 mweq yr-1, or approximately 15% of the average annual accumulation. An accumulation record representative of the WAIS Divide local area over recent centuries was developed using a principal component analysis of the array to identify the coherent accumulation signal. The WAIS Divide local area accumulation record did not exhibit a trend over recent centuries, with 14% inter-annual variability (1-standard deviation of the mean) and SSV of 0.017 mweq yr-1. Correlations between the WAIS Divide local accumulation record and atmospheric indices (e.g., Antarctic Oscillation and El-Nino Southern Oscillation) exhibited periods when the records oscillate in and out of phase. Thus, identifying relationships between WAIS Divide accumulation records and geophysical processes over recent centuries may be problematic.

McConnell, J. R.; Banta, J. R.

2008-12-01

306

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

307

Kinematic Identification of Parallel Mechanisms by a Divide and Conquer Strategy  

DEFF Research Database (Denmark)

This paper presents a Divide and Conquer strategy to estimate the kinematic parameters of parallel symmetrical mechanisms. The Divide and Conquer kinematic identification is designed and performed independently for each leg of the mechanism. The estimation of the kinematic parameters is performed using the inverse calibration method. The identification poses are selected optimizing the observability of the kinematic parameters from a Jacobian identification matrix. With respect to traditional identification methods the main advantages of the proposed Divide and Conquer kinematic identification strategy are: (i) reduction of the kinematic identification computational costs, (ii) improvement of the numerical efficiency of the kinematic identification algorithm and, (iii) improvement of the kinematic identification results. The contributions of the paper are: (i) The formalization of the inverse calibration method as the Divide and Conquer strategy for the kinematic identification of parallel symmetrical mechanisms and, (ii) a new kinematic identification protocol based on the Divide and Conquer strategy. As an application of the proposed kinematic identification protocol the identification of a planar 5R symmetrical mechanism is simulated. The performance of the calibrated mechanism is evaluated by updating the kinematic model with the estimated parameters and developing simulations.

Durango, Sebastian; Restrepo, David

2010-01-01

308

Chloroplasts divide by contraction of a bundle of nanofilaments consisting of polyglucan.  

Science.gov (United States)

In chloroplast division, the plastid-dividing (PD) ring is a main structure of the PD machinery and is a universal structure in the plant kingdom. However, the components and formation of the PD ring have been enigmatic. By proteomic analysis of PD machineries isolated from Cyanidioschyzon merolae, we identified the glycosyltransferase protein plastid-dividing ring 1 (PDR1), which constructs the PD ring and is widely conserved from red alga to land plants. Electron microscopy showed that the PDR1 protein forms a ring with carbohydrates at the chloroplast-division site. Fluorometric saccharide ingredient analysis of purified PD ring filaments showed that only glucose was included, and down-regulation of PDR1 impaired chloroplast division. Thus, the chloroplasts are divided by the PD ring, which is a bundle of PDR1-mediated polyglucan filaments. PMID:20724635

Yoshida, Yamato; Kuroiwa, Haruko; Misumi, Osami; Yoshida, Masaki; Ohnuma, Mio; Fujiwara, Takayuki; Yagisawa, Fumi; Hirooka, Shunsuke; Imoto, Yuuta; Matsushita, Kazunobu; Kawano, Shigeyuki; Kuroiwa, Tsuneyoshi

2010-08-20

309

Evaluation of lower leg swelling using EMG measured with voltage divider.  

Science.gov (United States)

The purpose of this study is to evaluate the lower leg swelling using EMG measured with our new voltage divider technology, by which the internal impedance of lower leg can be estimated. The amplitude of EMG measured without voltage divider was compared to it with voltage divider. Eleven healthy subjects (24.3±5.1 y.o.) participated in this study. Six female (swelling group) were asked to work at desk for six hours, and five male (control group) were asked to work a regular day. The internal impedance was calculated and calf circumference was measured before and after desk work. Results show that internal impedance in swelling group significantly decreased with increase in calf circumference, and our new evaluation method was proved to be effective for the evaluation of lower leg swelling. PMID:25570807

Murai, Akito; Sakaue, Yusuke; Makikawa, Masaaki

2014-08-01

310

Numerical Analysis of Pulsatile Blood Flow in a Stented Human Coronary Artery with a Flow Divider  

Directory of Open Access Journals (Sweden)

Full Text Available Shear stress is known to play a central role in restenosis formation and is sensitive to stent geometry. Local flow alterations created by a different stents without and with flow divider were studied to compare the hemodynamic effects of Stent design properties on restenosis in stented human coronary artery. Blood pressure and shear stress values were computed in three different sites, including stented arterial segment, pre-stent and post-stent regions using computational fluid dynamics. Blood flow was assumed as pulsatile, incompressible and Newtonian flow. Rigid boundary conditions were assumed for all models. The governing Navier-Stokes equations were solved using commercial software package (Fluent V6.0.12. Stents are assumed with real structure and modeled using the commercial software package (Gambit, V2.0. The arterial wall shear stress distribution was investigated in three major regions and critical sites were located. It is concluded that the wall shear stress between stent struts was sensitive to strut spacing, profile of strut, number of struts and curvature. Our 3D computational fluid dynamics modeling demonstrate that with increasing the angle between two sides of the stent strut the percentage of intrastrut area that exposed to critical value of WSS decreases. By application of a flow divider, the wall shear stress in stented segment increases markedly and so is the pressure gradient in stented segment. Flow divider influences the blood flow pattern in proximal of stented segment. In this section, the WSS increases with application of the flow divider. The results for different diameters of flow divider show that optimum diameter for flow divider is D/3.

Vahab Dehlaghi

2007-01-01

311

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

OpenAIRE

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

312

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

OpenAIRE

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

313

France and Germany divided over Syria arms embargo | EurActiv  

SCPinfonet

...France and Germany divided over Syria arms embargo | EurActiv east-mediterranean,global-europe,security,Catherine Ashton,human rights,Russia,Syria EU news & ... VIDEOS Home › Global Europe › News France and Germany divided over Syria arms embargo [fr] -A + A Published 12 March ...Tags Catherine Ashton, human rights, Russia, Syria France urged the European Union to look again at lifting an arms embargo on Syria to help ...chief Catherine Ashton put the emphasis on helping rebuild rebel-held areas of Syria. 'I am convinced that it is necessary we do more ...

314

Divide-and-conquer: A proportional, minimal-envy cake-cutting algorithm  

OpenAIRE

We analyze a class of proportional cake-cutting algorithms that use a minimal number of cuts (n-1 if there are n players) to divide a cake that the players value along one dimension. While these algorithms may not produce an envy-free or efficient allocation--as these terms are used in the fair-division literature--one, divide-and-conquer (D&C), minimizes the maximum number of players that any single player can envy. It works by asking n ? 2 players successively to place marks on a cake--...

Brams, Steven J.; Jones, Michael A.; Klamler, Christian

2010-01-01

315

An improved fully integrated, high-speed, dual-modulus divider  

Science.gov (United States)

A fully integrated 2n/2n+1 dual-modulus divider in GHz frequency range is presented. The improved structure can make all separated logic gates embed into correlative D flip—flops completely. In this way, the complex logic functions can be performed with a minimum number of devices and with maximum speed, so that lower power consumption and faster speed are obtained. In addition, the low-voltage bandgap reference needed by the frequency divider is specifically designed to provide a 1.0 V output. According to the design demand, the circuit is fabricated in 0.18 ?m standard CMOS process, and the measured results show that its operating frequency range is 1.1–2.5 GHz. The dual-modulus divider dissipates 1.1 mA from a 1.8 V power supply. The temperature coefficient of the reference voltage circuit is 8.3 ppm/°C when the temperature varies from ?40 to +125 °C. By comparison, the dual-modulus divide designed in this paper can possess better performance and flexibility.

Zheng, Sun; Yong, Xu; Guangyan, Ma; Hui, Shi; Fei, Zhao; Ying, Lin

2014-11-01

316

Narrowing the Digital Divide: "Head Start Teachers Develop Proficiency in Computer Technology"  

Science.gov (United States)

The Digital Divide originates with inequalities in children's access to computers. It is deepened by disparities in teacher readiness to use computers for educational purposes. This article describes a computer training program designed to help Head Start teachers develop attitudes, skills, and practices that maximize the educational benefits…

Chen, Jie-Qi; Price, Valerie

2006-01-01

317

The Digital Divide: The View from Latin America and the Caribbean.  

Science.gov (United States)

This paper discusses the digital divide from the perspective of Latin America and the Caribbean. Highlights include: new issues that make access to electronic resources difficult for users; differences in technological infrastructure among countries; how Internet users are distributed worldwide; Internet access in Africa; the number of students…

Rodriguez, Adolfo

318

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.

319

Q-measures for binary divided networks: an investigation within the field of informetrics  

OpenAIRE

Q-measures for binary divided networks, as introduced by Flom, Friedman, Strauss and Neaigus are studied. These measures try to capture the idea of bridges between two groups in a connected undirected network. Values for these measures are calculated for building blocks such as line and star networks. As an application two small co-author networks are analyzed.

Rousseau, Ronald

2005-01-01

320

The Racial Divide in Support for the Death Penalty: Does White Racism Matter?  

Science.gov (United States)

Using data from the 2000 National Election Study, this research investigates the sources of the racial divide in support for capital punishment with a specific focus on white racism. After delineating a measure of white racism, we explore whether it can account for why a majority of African Americans oppose the death penalty while most whites…

Unnever, James D.; Cullen, Francis T.

2007-01-01

321

Reassessing the Racial Divide in Support for Capital Punishment: The Continuing Significance of Race  

Science.gov (United States)

This project investigates the racial divide in support for capital punishment. The authors examine whether race has a direct effect on support for capital punishment and test whether the influence of race varies across class, being a native southerner, confidence in government officials, political orientation, and religious affiliation. Using data…

Unnever, James D.; Cullen, Francis T.

2007-01-01

322

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

323

Near-Earth Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2014 June-October  

Science.gov (United States)

Lightcurves for 45 near-Earth asteroids (NEAs) were obtained at the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) from 2014 June through October. Periods and lightcurve amplitudes were determined for 44 of the objects. No period or amplitude could be found for 2014 SZ144.

Warner, Brian D.

2015-01-01

324

Public attitudes on the gay marriage debate are divided along party lines  

OpenAIRE

The Minister for Women and Equalities, Maria Miller, made a statement to Parliament yesterday about gay marriage. Following this Ben Clements analyses the attitudes towards gay marriage among party supporters and finds that party affiliation is a clear dividing line in public opinion on this issue.

Clements, Ben

2012-01-01

325

Asteroid Lightcurve Analysis at the Palmer Divide Observatory - June-September 2006  

Science.gov (United States)

Lightcurves for 12 asteroids were obtained at the Palmer Divide Observatory from late June through late September 2006: 1355 Magoeba, 2083 Smither, 2150 Nyctimene, 3115 Baily, 3353 Jarvis, 5841 Stone, 6255 Kuma, (6382) 1988 EL, 9298 Geake, 9387 Tweedledee, 9739 Powell, and (22722) 1998 SE54.

Warner, Brian D.

2007-03-01

326

Closing the Digital Divide: Education Telecommunications Systems and Possibilities in Western Australia  

Science.gov (United States)

The research reported in this paper considers the current telecommunications network for the three education systems of state, independent and catholic schools in Western Australia as well as drawing on the personal experiences of teachers in these systems as the government attempts to close the digital divide with its Networking the Nation…

Trinidad, Sue

2007-01-01

327

Low-power wide-locking-range injection-locked frequency divider for OFDM UWB systems  

International Nuclear Information System (INIS)

This paper describes a divide-by-two injection-locked frequency divider (ILFD) for frequency synthesizers as used in multiband orthogonal frequency division multiplexing (OFDM) ultra-wideband (UWB) systems. By means of dual-injection technique and other conventional tuning techniques, such as DCCA and varactor tuning, the divider demonstrates a wide locking range while consuming much less power. The chip was fabricated in the Jazz 0.18 ?m RF CMOS process. The measurement results show that the divider achieves a locking range of 4.85 GHz (6.23 to 11.08 GHz) at an input power of 8 dBm. The core circuit without the test buffer consumes only 3.7 mA from a 1.8 V power supply and has a die area of 0.38 x 0.28 mm2. The wide locking range combined with low power consumption makes the ILFD suitable for its application in UWB systems.

328

Low-power wide-locking-range injection-locked frequency divider for OFDM UWB systems  

Energy Technology Data Exchange (ETDEWEB)

This paper describes a divide-by-two injection-locked frequency divider (ILFD) for frequency synthesizers as used in multiband orthogonal frequency division multiplexing (OFDM) ultra-wideband (UWB) systems. By means of dual-injection technique and other conventional tuning techniques, such as DCCA and varactor tuning, the divider demonstrates a wide locking range while consuming much less power. The chip was fabricated in the Jazz 0.18 mum RF CMOS process. The measurement results show that the divider achieves a locking range of 4.85 GHz (6.23 to 11.08 GHz) at an input power of 8 dBm. The core circuit without the test buffer consumes only 3.7 mA from a 1.8 V power supply and has a die area of 0.38 x 0.28 mm{sup 2}. The wide locking range combined with low power consumption makes the ILFD suitable for its application in UWB systems.

Yin Jiangwei; Li Ning; Zheng Renliang; Li Wei; Ren Junyan, E-mail: lining@fudan.edu.c [State Key Laboratory of ASIC and System, Fudan University, Shanghai 201203 (China)

2009-05-01

329

Gender Divide and Acceptance of Collaborative Web 2.0 Applications for Learning in Higher Education  

Science.gov (United States)

Situated in the gender digital divide framework, this survey study investigated the role of computer anxiety in influencing female college students' perceptions toward Web 2.0 applications for learning. Based on 432 college students' "Web 2.0 for learning" perception ratings collected by relevant categories of "Unified Theory of Acceptance and Use…

Huang, Wen-Hao David; Hood, Denice Ward; Yoo, Sun Joo

2013-01-01

330

From Atoms to Bits: Consequences of the Emerging Digital Divide in India.  

Science.gov (United States)

Discusses the impact of information and communication technologies (ICTs) and the digital divide in India. Considers the impact of information technologies, including the Internet and the Web, on the life and work of people; digital determinism; library and information infrastructure and superstructure; digital library initiatives; and the need…

Singh, Jagtar

2002-01-01

331

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.

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

332

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

333

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 irescine 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

334

Toxicological aspects of water  

International Nuclear Information System (INIS)

Different toxicological aspects of water have been studied, remarking the activity of various chemical substances in the organism. These substances are divided in: trace metals (Sb, As, Cd, Zn, Cu, Cr, Fe, Mn, Hg, Ni, Pb, Se), other contaminants (CN-, polycyclic aromatic hydrocarbons, phenols, pesticides, detergents) and radioactivity. Finally, some considerations on this subject are made

335

Fabrication of nanowire electronics on nonconventional substrates by water-assisted transfer printing method.  

Science.gov (United States)

We report a simple, versatile, and wafer-scale water-assisted transfer printing method (WTP) that enables the transfer of nanowire devices onto diverse nonconventional substrates that were not easily accessible before, such as paper, plastics, tapes, glass, polydimethylsiloxane (PDMS), aluminum foil, and ultrathin polymer substrates. The WTP method relies on the phenomenon of water penetrating into the interface between Ni and SiO(2). The transfer yield is nearly 100%, and the transferred devices, including NW resistors, diodes, and field effect transistors, maintain their original geometries and electronic properties with high fidelity. PMID:21696196

Lee, Chi Hwan; Kim, Dong Rip; Zheng, Xiaolin

2011-08-10

336

The Effect of Digital Divide on Information Accessibility among Undergraduate Students of Ahmadu Bello University, Zaria  

Directory of Open Access Journals (Sweden)

Full Text Available The study was undertaken to evaluate the effect of digital divide on information accessibility among undergraduate students of Ahmadu Bello University, Zaria. To accomplish this study, survey research was employed in gathering information from the sample population. Face to face method otherwise known as on the spot method of administration of questionnaire was adopted. The questionnaire was divided into two sections. Bio-data & the respondent’s, at the course of this study, it was discovered that ICT are not readily available to most undergraduate students. The study also established that the gap between the haves and the have not to be bridge, the institution’s management will need to ensure that the class rooms are internet connected and made available in every department to provide easy access to digital information especially to those who are financially incapacitated.

N.E.E. Achebe

2013-03-01

337

A fast divide-and-conquer algorithm for indexing human genome sequences  

CERN Document Server

Since the release of human genome sequences, one of the most important research issues is about indexing the genome sequences, and the suffix tree is most widely adopted for that purpose. The traditional suffix tree construction algorithms have severe performance degradation due to the memory bottleneck problem. The recent disk-based algorithms also have limited performance improvement due to random disk accesses. Moreover, they do not fully utilize the recent CPUs with multiple cores. In this paper, we propose a fast algorithm based on 'divide-and-conquer' strategy for indexing the human genome sequences. Our algorithm almost eliminates random disk accesses by accessing the disk in the unit of contiguous chunks. In addition, our algorithm fully utilizes the multi-core CPUs by dividing the genome sequences into multiple partitions and then assigning each partition to a different core for parallel processing. Experimental results show that our algorithm outperforms the previous fastest DIGEST algorithm by up t...

Loh, Woong-Kee; Lee, Wookey

2010-01-01

338

Divide and conquer is always best: sensitivity of methyl correlation experiments  

International Nuclear Information System (INIS)

The HMCM [CG]CBCA experiment (Tugarinov and Kay in J Am Chem Soc 125:13868–13878, 2003) correlates methyl carbon and proton shifts to C?, C?, and C? resonances for the purpose of resonance assignments. The relative sensitivity of the HMCM[CG]CBCA sequence experiment is compared to a divide-and-conquer approach to assess whether it is best to collect all of the methyl correlations at once, or to perform separate experiments for each correlation. A straightforward analysis shows that the divide-and-conquer approach is intrinsically more sensitive, and should always be used to obtain methyl-C?, C?, and C? correlations. The improvement in signal-to-noise associated with separate experiments is illustrated by the detection of methyl-aliphatic correlations in a 65 kDa protein-DNA complex

339

Image Segmentation using Enhanced K-means clustering with divide and Conquer Approach  

Directory of Open Access Journals (Sweden)

Full Text Available This paper present image segmentation using Enhanced k-means clustering with divide and conquer approach. First we enhanced the k-means clustering and then segment the image using enhanced approach. K-means is one of the most popular clustering algorithms. The final clustering result of the k-means clustering algorithm greatly depends upon the correctness of the initial centroids, which are selected randomly. Many improvements were already proposed to improve the performance of k-means, but most of these require initial k centroids .In this paper we have proposed a new method enhanced k-means clustering algorithm with divided and conquer algorithm to find the initial centroids with reduced time complexity. In this paper we fixed the initial centroids which gives best result and in the final step we segment the image using enhanced clustering algorithm.

Babeesh Kumar

2014-07-01

340

ESTADO DEL ARTE EN LAS IMPLEMENTACIONES PARALELAS DE DIVIDE Y VENCERÁS  

Directory of Open Access Journals (Sweden)

Full Text Available

Divide y Vencerás, es una técnica de diseño de algoritmos ampliamente utilizada en la solución de problemas. Su implementación en paralelo resulta natural. En este trabajo se realiza una revisión bibliográfica acerca del desarrolo de algoritmos paralelos con este paradigma. En ambientes paralelos heterogéneos se mejoran las prestaciones, si en el diseño de algoritmos se tienen en cuenta las características de los procesadores utilizados y de las comunicaciones entre elos. Los trabajos analizados desarrolan implementaciones paralelas de algoritmos basados en "Divide y Vencerás" solamente en sistemas homogéneos. Resulta imprescindible el estudio y desarrollo de este paradigma en ambientes heterogéneos.

Ernesto Carbonell Rigores

2006-04-01

341

Depletion of MOM1 in non-dividing cells of Arabidopsis plants releases transcriptional gene silencing.  

Science.gov (United States)

Mitotic and meiotic inheritance of epigenetic information is coupled to the reproduction of chromatin conformation and DNA methylation patterns. This implies that the S phase of the cell cycle provides a window of opportunity for changes in epigenetic determination. Recent studies, however, have suggested that chromatin structure is also rather dynamic in quiescent cells of multicellular eukaryotes and that silent heterochromatic regions can become accessible to transcription. Such epigenetic flexibility in differentiated tissues could be of physiological importance. The mechanisms and molecular components involved are of great interest but as yet unknown. We examined MOM1 (Morpheus' Molecule 1), a regulator of transcriptional gene silencing (TGS) that acts independently of DNA methylation, for its role in the maintenance of TGS in non-dividing, differentiated cells. The results provide evidence that TGS maintenance mediated by MOM1 is a dynamic process that can be modified in non-dividing cells of mature plant organs by depletion of MOM1. PMID:12231508

Tariq, Muhammad; Habu, Yoshiki; Paszkowski, Jerzy

2002-10-01

342

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

343

Calibrated current divider network for precision current delivery during high-voltage transthoracic defibrillation.  

Science.gov (United States)

The design of a calibrated resistive-network current divider for precision current delivery during transthoracic defibrillation shocks is presented together with test results. The current divider presents a constant 50-ohm load to the defibrillator and thus maintains a constant pulse shape. Current is selected before the shock by setting three rheostats using a computer-generated calibration table. Following each shock, the data acquisition and display software updates the calibration table based on the measured value of transthoracic resistance. Over a range of 15-27 A, the root-mean-square (rms) error for delivered versus selected current was 0.48% for a 45-ohm resistive load, and 0.71% for a 100-ohm load. These test results were confirmed by animal experiments. Over 3 dogs, the rms error was 0.49% from 15-27 A and not greater than 1.5% over the entire 8-44 A range. PMID:16285402

Deale, O Carlton; Ng, Kwong T; Lerman, Bruce B

2005-11-01

344

Consideration of pinning and dissolution with dividing sites in Monte Carlo simulation of grain growth  

International Nuclear Information System (INIS)

Various distributions of particle size are considered in the present work to study the effect of pinning by a bimodal distribution of particles on grain growth simulation in comparison with that of the real distribution of MnS (30-50 nm) and AlN (5-8 nm) in a Fe3%Si alloy grade HiB. A dividing site technique is used to make easy consideration of different size of particles together without increasing matrix size for calculation. The dissolution of precipitates introduced after the stagnation stage allows grain growth to start again.The dividing sites technique allows the consideration of particle dissolution by gradual vanishing of peripheral layers of particles, in agreement with the experimental evolution.

345

Generation of megawatt peak power picosecond pulses from a divided-pulse fiber amplifier  

OpenAIRE

Control of nonlinearity is a challenge in fiber amplifiers designed to generate pulses of a few picoseconds duration, and as a result, picosecond fiber amplifiers have failed to reach peak power of 1 megawatt. Divided-pulse amplification, combined with the use of circular polarization, allows the generation of 2.2-ps pulses with energy as high as 2.5 ?J and peak power of 1 MW.

Kong, L. J.; Zhao, L. M.; Lefrancois, S.; Ouzounov, D. G.; Yang, C. X.; Wise, F. W.

2012-01-01

346

Generation of megawatt peak power picosecond pulses from a divided-pulse fiber amplifier.  

Science.gov (United States)

Control of nonlinearity is a challenge in fiber amplifiers designed to generate pulses of a few picoseconds duration, and as a result, picosecond fiber amplifiers have failed to reach peak power of 1MW. Divided-pulse amplification, combined with the use of circular polarization, allows the generation of 2.2 ps pulses with energy as high as 2.5 ?J and peak power of 1 MW. PMID:22854484

Kong, L J; Zhao, L M; Lefrancois, S; Ouzounov, D G; Yang, C X; Wise, F W

2012-01-15

347

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

OpenAIRE

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...

Al-rababah, Boran A.; Abu-shanab, Emad A.

2010-01-01

348

Software Cost Estimation Framework for Service-Oriented Architecture Systems using Divide-and-Conquer Approach  

OpenAIRE

Due to the complexity of Service-Oriented Architecture (SOA), cost and effort estimation for SOA-based software development is more difficult than that for traditional software development. Unfortunately, there is a lack of published work about cost and effort estimation for SOA-based software. Existing cost estimation approaches are inadequate to address the complex service-oriented systems. This paper proposes a novel framework based on Divide-and-Conquer (D&C) for cost es...

Li, Zheng; Keung, Jacky

2013-01-01

349

Selective exclusion: the digital divide in the context of indigenous knowledge systems in South Africa  

OpenAIRE

This article provides an alternative view to questions of technological inclusion and exclusion in sub-Saharan Africa via an analysis of the South African governmental discourse on indigenous knowledge systems (IKS). The concept of 'selective exclusion' (SE) is developed in relation to the digital divide, highlighting that technology is not always perceived as neutral or universally beneficial, but rather is negotiated in relation to specific socio-political contexts and alternative systems o...

Lotriet, H.; Matthee, M.; Mazanderani, F.

2009-01-01

350

Selective exclusion : the digital divide in the context of indigenous knowledge systems in South Africa  

OpenAIRE

This article provides an alternative view to questions of technological inclusion and exclusion in sub-Saharan Africa via an analysis of the South African governmental discourse on indigenous knowledge systems (IKS). The concept of 'selective exclusion' (SE) is developed in relation to the digital divide, highlighting that technology is not always perceived as neutral or universally beneficial, but rather is negotiated in relation to specific socio-political contexts and alternative system...

Lotriet, H. H.; Matthee, Machdel C.; Mazanderani, F.

2009-01-01

351

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

OpenAIRE

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 ...

Katie Brown; Campbell, Scott W.; Rich Ling

2011-01-01

352

Contested Normative Cultures. Gendered Perspectives on Religions and the Public/Private Divide.  

DEFF Research Database (Denmark)

The article considers religious and secular normative cultures from a gendered perspective focusing on gender and the class and gender privileges linked to the introduction of a public/private divide. It finally discusses issues concerning 'gender display' and gender performance in the 21st century as a field, where 'religion', 'public', 'private' and 'gender' overlap, interact, and possibly take on new forms and new meanings and changes all involved actors.

Petersen, Hanne

2012-01-01

353

Book review: The price of inequality: how today’s divided society endangers our future.  

OpenAIRE

"The Price of Inequality: How Today’s Divided Society Endangers Our Future." Joseph Stiglitz. Penguin. April 2013. --- America currently has the most inequality and the least equality of opportunity among the developed countries, writes Nobel Prize-winning economist Joseph E. Stiglitz in The Price of Inequality. While market forces play a role in this stark picture, politics has shaped those market forces. Stiglitz aims to explain how inequality affects and is affected by every aspect of...

Krupa, Joel

2013-01-01

354

The leisure divide: Can the 'Third World' come out to play?  

OpenAIRE

As billions of dollars are invested in mitigating the digital divide, stakes are raised to gain validity for these cost-intensive endeavors, focusing more on online activities that have clear socio-economic outcomes. Hence, farmers in rural India are watched closely to see how they access crop prices online, while their Orkuting gets sidelined as anecdotal. This paper argues that this is a fundamental problem as it treats users in emerging markets as somehow inherently different from those in...

Arora, P. A.

2012-01-01

355

Bridging the Divide: Tensions Between the Biophysical and Social Sciences in An Interdisciplinary Sustainability Science Project  

OpenAIRE

Interdisciplinary research has gained tremendous popularity in higher education over the past several decades and funding for such efforts through federal agencies has underscored its relevance. In sustainability science, in particular, interdisciplinarity is seen as integral to the research endeavor. However, a paucity of empirical evidence exists regarding the process of interdisciplinary endeavors, particularly those that cross the social-biophysical science divide. The current study in...

Gardner, Susan K.

2014-01-01

356

The Indonesian digital library network is born to struggle with the digital divide  

OpenAIRE

IndonesiaDLN –The Indonesian Digital Library Network– is a distributed collection of digital library networks, digital library servers, full local contents, metadata, and people for the development of the Indonesian knowledge-based society. Beside the general issues of digital library such as publishing, quality control, authentication, networking, and information retrieval, we also face other issue –namely digital divide– in designing and implementing the Network. This paper describe...

Fahmi, Ismail

2001-01-01

357

Effect of Information and Communication Technologies (ICT on Non-Industrial Countries-Digital Divide Model  

Directory of Open Access Journals (Sweden)

Full Text Available The influence of information and communication technology on the collective activities and interests of a broad range of people was discussed and analyzed. The important consequence of ICT called digital divide was mathematically modeled and the results analyzed. The closed loop feedback model proved the need for a society to be educationally, culturally, economically and politically ready to integrate and implement new technologies into its infrastructure.

Mahmoud Z. Iskandarani

2008-01-01

358

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

OpenAIRE

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

Segarani Naidoo; Jaya Raju

2012-01-01

359

Bridging the digital divide – digital libraries in information literacy instruction in India and Germany  

OpenAIRE

Digital libraries create new possibilities of accessing information worldwide. Conditions for use are technical equipment on the one hand and information literacy skills on the other hand. A lack of information literacy skills may lead to a digital divide between information literate ‘onliners’ and information illiterate ‘nonliners’. Libraries improve usage of digital libraries through information literacy instruction as integral part in the lifelong learning process. Academic librari...

Klingenberg, Andreas; Singh, Neena

2010-01-01

360

A high-bandwidth, high-voltage divider for neutral injectors  

International Nuclear Information System (INIS)

A description is given of the design, construction, calibration and testing of a voltage divider for which the influence of space potential variation as well as the pick-up of RF- and inductive interference is grossly reduced by its special design. It features voltage capability up to 160 kV, measuring accuracy approaching 10-3 over a bandwidth from d.c. to 100 kHz with negligible phase error, and useful measuring capability to beyond 10 MHz. (author)

361

Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2014 June-October  

Science.gov (United States)

Lightcurves for 24 main-belt asteroids were obtained at the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) from 2014 June through October. Some objects were members of the Hungaria orbital group or collisional family, observed as follow-up to previous apparitions to check for undiscovered satellites, to improve previous binary discovery parameters, or to obtain data for spin axis and shape modeling.

Warner, Brian D.

2015-01-01

362

Bridging “Digital Divide” in Medium and Small-sized Enterprises’Informatization  

OpenAIRE

Great significance lies in the informatization of medium and small-sized enterprises in that it will convert the economic growth method and improve those enterprises’ competitive abilities at the international market. However, “digital divide” confronted in their informatization must be bridged by reinforcing the support for their informatization process, achieving the goal of informatization step by step, actively promoting “the Enterprises’ Informatization Project” and soundly c...

Baozhen Chen

2009-01-01

363

Divide and conquer the Hilbert space of translation-symmetric spin systems  

OpenAIRE

Iterative methods that operate with the full Hamiltonian matrix in the untrimmed Hilbert space of a finite system continue to be important tools for the study of one- and two-dimensional quantum spin models, in particular in the presence of frustration. To reach sensible system sizes such numerical calculations heavily depend on the use of symmetries. We describe a divide-and-conquer strategy for implementing translation symmetries of finite spin clusters, which efficiently ...

Weiße, Alexander

2012-01-01

364

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

OpenAIRE

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

365

Multi-resolution two-sample comparison through the divide-merge Markov tree  

OpenAIRE

We introduce a probabilistic framework for two-sample comparison based on a nonparametric process taking the form of a Markov model that transitions between a "divide" and a "merge" state on a multi-resolution partition tree of the sample space. Multi-scale two-sample comparison is achieved through inferring the underlying state of the process along the partition tree. The Markov design allows the process to incorporate spatial clustering of differential structures, which is...

Soriano, Jacopo; Ma, Li

2014-01-01

366

Sector Dividing Method in Enroute Radar Airspace with Unbalanced Traffic Distribution  

OpenAIRE

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 Controller)ATC additional workload associating with coordinating, handover and resolve conflicts,...

Zhijian Ye; Linhang Meng; Wei Gao; Zengxian Geng; Qiu Xiang

2013-01-01

367

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

368

Crossing the phantom divide in brane cosmology with curvature corrections and brane-bulk energy transfer  

International Nuclear Information System (INIS)

We consider the Randall-Sundrum brane-world model with bulk-brane energy transfer where the Einstein-Hilbert action is modified by curvature correction terms: a four-dimensional scalar curvature from induced gravity on the brane, and a five-dimensional Gauss-Bonnet curvature term. It is remarkable that these curvature terms will not change the dynamics of the brane universe at low energy. Parameterizing the energy transfer and taking the dark radiation term into account, we find that the phantom divide of the equation of state of effective dark energy could be crossed, without the need of any new dark energy components. Fitting the two most reliable and robust SNIa datasets, the 182 Gold dataset and the Supernova Legacy Survey (SNLS), our model indeed has a small tendency of phantom divide crossing for the Gold dataset, but not for the SNLS dataset. Furthermore, combining the recent detection of the SDSS baryon acoustic oscillations peak (BAO) with lower matter density parameter prior, we find that the SNLS dataset also mildly favors phantom divide crossing

369

Lipid droplet organelle distribution in populations of dividing cells studied by simulation  

International Nuclear Information System (INIS)

One of the key questions in cell biology is how organelles are passed from parent to daughter cells. To help address this question, I used Brownian dynamics to simulate lipid droplets as model organelles in populations of dividing cells. Lipid droplets are dynamic bodies that can form both de novo and by fission, they can also be depleted. The quantitative interplay among these three events is unknown but would seem crucial for controlling droplet distribution in populations of dividing cells. Surprisingly, of the three main events studied: biogenesis, fission, and depletion, the third played the key role in maintaining droplet organelle number—and to a lesser extent volume—in populations of dividing cells where formation events would have seemed paramount. In the case of lipid droplets, this provides computational evidence that they must be sustained, most likely through contacts with the endoplasmic reticulum. The findings also agree with video microscopy experiments over much shorter timescales where droplet depletion in fission yeast cells was not observed. In general, this work shows that organelle maintenance is invaluable and lack thereof cannot necessarily be compensated for by organelle formation. This study provides a time-accurate, physical-based template for long-term cell division studies. (paper)

370

Injection circuit to the HV GRID using Adaptive Fuzzy Dividing Frequency-Control Method  

Science.gov (United States)

This paper deals with a hybrid active power filter with injection circuit (IHAPF). It exhibits clear promise in decreasing harmonics and increasing the power factor with a comparatively low capacity active power filter. This paper concludes that the stability of the IHAPF based on spotting supply current is exceptional to that of others. To minimize the capacity of IHAPF, an adaptive fuzzy dividing frequency control method is used, which consists of two control units: a generalized integrator control unit and fuzzy adjustor unit. The generalized integrator is used for dividing the frequency integral control, while fuzzy arithmetic is used for adjusting proportional-integral coefficients timely. And the control method is generally useful and applicable to any other active filters. Compared to other IHAPF control methods, the adaptive fuzzy dividing frequency control shows the advantages of shorter response time and higher control precision. It is implemented in an IHAPF with a 100-k VA APF installed in a copper mill in Northern China. The simulation and experimental results show that the new control method is not only easy to be calculated and implemented, but also very effective in reducing harmonics.

Reddy, Bodha venugopal; Reddy, N. Narender

2012-07-01

371

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

372

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 termination criterion based on maximum likelihood is introduced in the measurement update step, so the MLIDDF is guaranteed to produce a sequence estimate that moves up the maximum likelihood surface. In a simulation, its performance is compared against that of the unscented Kalman filter (UKF, divided difference filter (DDF, iterated unscented Kalman filter (IUKF and iterated divided difference filter (IDDF both using a traditional iteration strategy. Simulation results demonstrate that the accumulated mean-square root error for the MLIDDF algorithm in position is reduced by 63% compared to that of UKF and DDF algorithms, and by 7% compared to that of IUKF and IDDF algorithms. The new algorithm thus has better state estimation accuracy and a fast convergence rate.

Changyuan Wang

2012-06-01

373

77 FR 73049 - Notice of Availability of the Draft Environmental Impact Statement for the Continental Divide...  

Science.gov (United States)

...coal bed natural gas wells, using a combination...include well pads, gas and water collection...pipelines, compressor stations, water disposal...has been undergoing natural gas development since...landscape scale impact reduction through...

2012-12-07

374

Changes of the main parameters of the primary heat transport system of the Embalse NPP after the replacement of the divider plates of the steam generators  

International Nuclear Information System (INIS)

Divider plates of the four steam generators were repaired at Embalse NPP during the outage of 2002. This task led to a reduction of heavy water by-pass from the hot to the cold side. As a consequence of this, some Primary Heat Transport System (PHTS) parameters were affected. The main results of this work are the following: a) Bulk PHTS flow did not change significantly; b) Inlet Header temperature dropped 2,8 C degrees at full power; c) Quality at Outlet Header is now practically negligible. (author)

375

Effects of nonlinear rheology, temperature and anisotropy on the relationship between age and depth at ice divides  

OpenAIRE

Ice flow in divide areas is strongly anisotropic. The evolution of ice fabric, from the onset of divide flow towards steady-state with a fully-developed fabric, has been shown to profoundly affect both the stratigraphy and surface topography of ice divides. Here, we investigate the effects of ice flow on the age-versus-depth relationship at ice divides by using a full Stokes thermomechanical model with a non-linear anisotropic constitutive relation between stress and strain rates. We c...

Marti?n, C.; Gudmundsson, G. H.

2012-01-01

376

75 FR 69435 - Public Water System Supervision Program Revision for the State of North Dakota  

Science.gov (United States)

...National Primary Drinking Water Regulations (NPDWR...not extend to public water systems in Indian country...Region 8, Drinking Water Program, 1595 Wynkoop...Health, Division of Municipal Facilities, 918 East Divide,...

2010-11-12

377

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.

378

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

379

Analysis of Water abstraction and Water demand in the Netherlands  

OpenAIRE

Research into water consumption by various consumer categories is at present being carried out to support and sustain implementation of the governmental policy . In this overview of the results of water abstraction analyses and demand in the Netherlands, emphasis has been put on quantitative aspects. In general terms, water use can be divided into consumptive uses, of which a significant share of total supply does not return directly to its source (i.e. household, indu...

Jhc, Muelschlegel; Fj, Kragt

2012-01-01

380

Generic feature of future crossing of phantom divide in viable f(R) gravity models  

International Nuclear Information System (INIS)

We study the equation of state for dark energy and explicitly demonstrate that the future crossings of the phantom divide line wDE = ?1 are the generic feature in the existing viable f(R) gravity models. We also explore the future evolution of the cosmological horizon entropy and illustrate that the cosmological horizon entropy oscillates with time due to the oscillatory behavior of the Hubble parameter. The important cosmological consequence is that in the future, the sign of the time derivative of the Hubble parameter changes from negative to positive in these viable f(R) gravity models

381

A Markov Model for Human Resources Supply Forecast Dividing the HR System into Subgroups  

Directory of Open Access Journals (Sweden)

Full Text Available Modeling the manpower management mainly concerns the prediction of future behavior of employees. The paper presents a predictive model of numbers of employees in a hierarchical dependent-time system of human resources, incorporating subsystems that each contains grades of the same family. The proposed model is motivated by the reality of staff development which confirms that the path evolution of each employee is usually in his family of grades. That is the reason of dividing the system into subgroups and the choice of the superdiagonal transition matrix.

Rachid Belhaj

2013-08-01

382

Asteroid lightcurve analysis at the Palmer Divide Observatory - late 2005 and early 2006  

Science.gov (United States)

Lightcurves for 23 of 24 asteroids were obtained at the Palmer Divide Observatory from November 2005 through early February 2006: 224 Oceana, 332 Siri, 494 Virtus, 549 Jessonda, 573 Recha, 596 Scheila, 773 Irmintraud, 840 Zenobia, 1207 Ostenia, 1238 Predappia, 1613 Smiley, 1694 Kaiser, 2839 Annette, 2856 Roeser, 3511 Tsvetaeva, 3635 Kreutz, 3873 Roddy, 4283 Stoffler, 4547 Massachusetts, (5877) 1990 FP, (18582) 1997 XK9, and (21056) 1991 CA1. In addition, a revised period for 1582 Martir based on data obtained in 2000 is presented.

Warner, Brian D.

2006-09-01

383

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 Arnol’d tongues in the frequency–amplitude plane. In particular, we provide exact analytical formulae for the widths of the tongues, which correspond to the plateaux of the devil’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

384

Divided Co-Ownership and Matrimonial Property in Legal Regulations of Slovak Republic  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of the study is to transparently outline a system of relations connected with two different forms of property right that are incorporated in Slovak legal system. In this study author dealt with principles of the divided co-ownership and matrimonial property which lead to the pointing up to the differences between these legal concepts. On the basis of analysis of the null and present rules of law author persuade to the conclusions which are evaluation of the present status and inevitability of the changes in the future.

Magdaléna Kerul’ová

2008-07-01

385

Arnold tongues for a resonant injection-locked frequency divider: analytical and numerical results  

CERN Document Server

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 Arnold tongues in the frequency-amplitude plane. In particular, we provide exact analytical formulae for the widths of the tongues, which correspond to the plateaux of the devil'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 V; Gentile, Guido; Schilder, Frank

2009-01-01

386

ZoneLib : A Simulink Library for Modeling Zone Divided Climate Dynamics  

DEFF Research Database (Denmark)

We present a dynamic model for climate in a livestock building divided into a number of zones, and a corresponding modular Simulink library (ZoneLib). While most literature in this area consider air flow as a control parameter we show how to model climate dynamics using actual control signals for the ventilation equipment. To   overcome a shortcoming in Simulink to solve algebraic equations and matrix inversions, we have developed the library inspired by the so called dynamic node technique. We present simulation results using the presented library, and concludes with visions for further development of ZoneLib.

Jessen, Jan Jacob; SchiØler, Henrik

2006-01-01

387

A recursive divide-and-conquer approach for sparse principal component analysis  

OpenAIRE

In this paper, a new method is proposed for sparse PCA based on the recursive divide-and-conquer methodology. The main idea is to separate the original sparse PCA problem into a series of much simpler sub-problems, each having a closed-form solution. By recursively solving these sub-problems in an analytical way, an efficient algorithm is constructed to solve the sparse PCA problem. The algorithm only involves simple computations and is thus easy to implement. The proposed m...

Zhao, Qian; Meng, Deyu; Xu, Zongben

2012-01-01

388

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

389

2.4G ~ 10.4G Hz CMOS programmable Frequency Divider  

OpenAIRE

This master thesis is as a final project in the Division of Computer Engineering at the Department of Electrical Engineering, Linköpings University, Sweden. The purpose of the project is to design a wide frequency range programmable frequency divider used in a PLL circuit for ultra wide band system. 0.18 um tsmc CMOS technology is used in this project. A brief introduction of PLL circuits and UWB specifications are given in the report and the circuit design issue is presented. Post-layout ...

Kang, Shi-yun; Wen, Hsiang-chih

2005-01-01

390

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

391

High-impedance capacitive divider probe for potential measurements in plasmas  

International Nuclear Information System (INIS)

It is often desirable, though difficult, to measure electric potential changes within a plasma, including variations due to waves and fluctuations. For a broad range of plasma parameters ac floating potential measurements may be made using the high input impedance probe described in this paper. A capacitive divider with an active buffer circuit is incorporated, such that a 50-? line can be driven with a 60-dB dynamic range and 100-MHz bandwidth. Details of the electronic circuit, mechanical construction, and calibration of the probe are given, together with a discussion of the parameter range over which successful measurements may be made

392

China and the G-21 : a new North-South divide in the WTO after Cancún?  

OpenAIRE

The paper analyses the interests of China as a member of the G-21, which contributed to the failure of the WTO Ministerial Conference in Cancún/Mexico in September 2003. It concludes that the median member of G-21 is more inward-looking and less reform-minded than China. A failure of the Doha Round due to a North-South divide between the US/EU on the one hand and the G-21 on the other hand would cause more harm to the latter than to the former group and would also impact negatively upon Chin...

Langhammer, Rolf J.

2004-01-01

393

Ground-water travel time  

International Nuclear Information System (INIS)

The Containment and Isolation Working Group considered issues related to the postclosure behavior of repositories in crystalline rock. This working group was further divided into subgroups to consider the progress since the 1978 GAIN Symposium and identify research needs in the individual areas of regional ground-water flow, ground-water travel time, fractional release, and cumulative release. The analysis and findings of the Ground-Water Travel Time Subgroup are presented

394

Regional ground-water system  

International Nuclear Information System (INIS)

The Containment and Isolation Working Group considered issues related to the postclosure behavior of repositories in crystalline rock. This working group was further divided into subgroups to consider the progress since the 1978 GAIN Symposium and identify research needs in the individual areas of regional ground-water flow, ground-water travel time, fractional release, and cumulative release. The analysis and findings of the Ground-Water Regime Subgroup are presented

395

Effects of nonlinear rheology, temperature and anisotropy on the relationship between age and depth at ice divides  

Directory of Open Access Journals (Sweden)

Full Text Available Ice flow in divide areas is strongly anisotropic. The evolution of ice fabric, from the onset of divide flow towards steady-state with a fully-developed fabric, has been shown to profoundly affect both the stratigraphy and surface topography of ice divides. Here, we investigate the effects of ice flow on the age-versus-depth relationship at ice divides by using a full Stokes thermomechanical model with a non-linear anisotropic constitutive relation between stress and strain rates. We compare our results with analytical approximations commonly employed in age–depth predictions such as the Dansgaard and Lliboutry approximations. We show that these approximations systematically underestimate the age of ice at fully-developed divides by as much as one order of magnitude. We also show that divides with fully-developed fabric are ideal locations for ice-core extraction because ice under them can be up to one order of magnitude older than ice at the same depth at the flanks. In addition, these divides have a distinctive morphological structure that allows them to be clearly identified from satellite imagery or ground-penetrating radar data. Our results are particularly relevant in coastal areas of Antarctica where divides with fully-developed ice fabric are widespread.

C. Martín

2012-06-01

396

Handling zone dividing method in packed bed liquid desiccant dehumidification/regeneration process  

Energy Technology Data Exchange (ETDEWEB)

Dehumidifier and regenerator are the most significant components in liquid desiccant air-conditioning systems, in which air directly contacts liquid desiccant and heat and mass transfer process occurs between the two fluids. Heat transfer process and mass transfer process within dehumidifier/regenerator influence each other and should not be separately considered. Based on the previous reachable handling region analysis, a zonal method is proposed in present study. Four zones are divided in the psychrometric chart according to the relative position of inlet air to inlet desiccant including two dehumidification zones, zone A and zone D, and two regeneration zones, zone B and zone C. In zone A or C, mass transfer is key process, and counter-flow configuration has the best mass transfer performance and parallel-flow is the poorest in the same operating conditions. In zone B or D, heat transfer is governing process, parallel-flow has the best mass transfer performance and counter-flow is the poorest. In order to obtain better mass transfer performance, liquid desiccant should be cooled (in zone A) rather than air (in zone D) in dehumidifier, and liquid desiccant should be heated (in zone C) rather than air (in zone B) in regenerator. The divided zones and the corresponding zonal properties will be helpful to the design and optimization of dehumidifiers and regenerators. (author)

Liu, X.H.; Jiang, Y. [Dept. of Building Science, School of Architecture, Tsinghua Univ., Beijing 100084 (China)

2009-12-15

397

Handling zone dividing method in packed bed liquid desiccant dehumidification/regeneration process  

International Nuclear Information System (INIS)

Dehumidifier and regenerator are the most significant components in liquid desiccant air-conditioning systems, in which air directly contacts liquid desiccant and heat and mass transfer process occurs between the two fluids. Heat transfer process and mass transfer process within dehumidifier/regenerator influence each other and should not be separately considered. Based on the previous reachable handling region analysis, a zonal method is proposed in present study. Four zones are divided in the psychrometric chart according to the relative position of inlet air to inlet desiccant including two dehumidification zones, zone A and zone D, and two regeneration zones, zone B and zone C. In zone A or C, mass transfer is key process, and counter-flow configuration has the best mass transfer performance and parallel-flow is the poorest in the same operating conditions. In zone B or D, heat transfer is governing process, parallel-flow has the best mass transfer performance and counter-flow is the poorest. In order to obtain better mass transfer performance, liquid desiccant should be cooled (in zone A) rather than air (in zone D) in dehumidifier, and liquid desiccant should be heated (in zone C) rather than air (in zone B) in regenerator. The divided zones and the corresponding zonal properties will be helpful to the design and optimization of dehumidifiers and regenerators.

398

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

399

The plastid of Toxoplasma gondii is divided by association with the centrosomes.  

Science.gov (United States)

Apicomplexan parasites harbor a single nonphotosynthetic plastid, the apicoplast, which is essential for parasite survival. Exploiting Toxoplasma gondii as an accessible system for cell biological analysis and molecular genetic manipulation, we have studied how these parasites ensure that the plastid and its 35-kb circular genome are faithfully segregated during cell division. Parasite organelles were labeled by recombinant expression of fluorescent proteins targeted to the plastid and the nucleus, and time-lapse video microscopy was used to image labeled organelles throughout the cell cycle. Apicoplast division is tightly associated with nuclear and cell division and is characterized by an elongated, dumbbell-shaped intermediate. The plastid genome is divided early in this process, associating with the ends of the elongated organelle. A centrin-specific antibody demonstrates that the ends of dividing apicoplast are closely linked to the centrosomes. Treatment with dinitroaniline herbicides (which disrupt microtubule organization) leads to the formation of multiple spindles and large reticulate plastids studded with centrosomes. The mitotic spindle and the pellicle of the forming daughter cells appear to generate the force required for apicoplast division in Toxoplasma gondii. These observations are discussed in the context of autonomous and FtsZ-dependent division of plastids in plants and algae. PMID:11134072

Striepen, B; Crawford, M J; Shaw, M K; Tilney, L G; Seeber, F; Roos, D S

2000-12-25

400

Dividing Line between Quantum and Classical Trajectories in a Measurement Problem: Bohmian Time Constant  

Science.gov (United States)

This Letter proposes an answer to a challenge posed by Bell on the lack of clarity in regards to the dividing line between the quantum and classical regimes in a measurement problem. To this end, a generalized logarithmic nonlinear Schrödinger equation is proposed to describe the time evolution of a quantum dissipative system under continuous measurement. Within the Bohmian mechanics framework, a solution to this equation reveals a novel result: it displays a time constant that should represent the dividing line between the quantum and classical trajectories. It is shown that continuous measurements and damping not only disturb the particle but compel the system to converge in time to a Newtonian regime. While the width of the wave packet may reach a stationary regime, its quantum trajectories converge exponentially in time to classical trajectories. In particular, it is shown that damping tends to suppress further quantum effects on a time scale shorter than the relaxation time of the system. If the initial wave packet width is taken to be equal to 2.8×10-15m (the approximate size of an electron), the Bohmian time constant is found to have an upper limit, i.e., ?Bmax?=10-26s.

Nassar, Antonio B.; Miret-Artés, Salvador

2013-10-01

401

Discovery of Opinion Leader Community Via Multilayer Structure based Time-dividing Approach  

Directory of Open Access Journals (Sweden)

Full Text Available With the advent of web 3.0, social network has become an important way to disclosure and spread the public sentiment. Opinion leaders play an important role in leading the direction of the public opinion. In this paper, due to the structure of the community in the network, we extracted the community by replies of each post in BBS, and we came up with an opinion leader community mining method based on level structure. In this way the communities each other have a better overlap result. Thus, communities can have more relations. Then, we analyzed the revolution of the communities after we got the structure of the opinion leader communities and we put forward a time-dividing method, and divided the whole communities into different pieces based on the character of the post and the duration of the time and we came up with the suitable measurement parameter to get the evolution result of the communities. Finally, experiments prove the efficiency of the opinion leader community mining method and we summarize the properties of the opinion leader community in revolution.

Yan Liu

2013-07-01

402

A study on how to divide and recodify the atomic energy act and its related regulations  

Energy Technology Data Exchange (ETDEWEB)

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.

Lee, Kyung Hui; Chung, Sang Ki; Lee, Sang Soo [Hannam Univ., Taejon (Korea, Republic of); Myung, Jae Jin [Chungnam National Univ., Taejon (Korea, Republic of)

2003-02-15

403

Ensemble Kalman filtering with a divided state-space strategy for coupled data assimilation problems  

CERN Document Server

This study considers the data assimilation problem in coupled systems, which consists of two components (sub-systems) interacting with each other through certain coupling terms. A straightforward way to tackle the assimilation problem in such systems is to concatenate the states of the sub-systems into one augmented state vector, so that a standard ensemble Kalman filter (EnKF) can be directly applied. In this work we present a divided state-space estimation strategy, in which data assimilation is carried out with respect to each individual sub-system, involving quantities from the sub-system itself and correlated quantities from other coupled sub-systems. On top of the divided state-space estimation strategy, we also consider the possibility to run the sub-systems separately. Combining these two ideas, a few variants of the EnKF are derived. The introduction of these variants is mainly inspired by the current status and challenges in coupled data assimilation problems, and thus might be of interest from a pr...

Luo, Xiaodong

2014-01-01

404

Ensemble Kalman Filtering with a Divided State-Space Strategy for Coupled Data Assimilation Problems*  

Science.gov (United States)

This study considers the data assimilation problem in coupled systems, which consists of two components (sub-systems) interacting with each other through certain coupling terms. A straightforward way to tackle the assimilation problem in such systems is to concatenate the states of the sub-systems into one augmented state vector, so that a standard ensemble Kalman filter (EnKF) can be directly applied. In this work we present a divided state-space estimation strategy, in which data assimilation is carried out with respect to each individual sub-system, involving quantities from the sub-system itself and correlated quantities from other coupled sub-systems. On top of the divided state-space estimation strategy, we also consider the possibility to run the sub-systems separately. Combining these two ideas, a few variants of the EnKF are derived. The introduction of these variants is mainly inspired by the current status and challenges in coupled data assimilation problems, and thus might be of interest from a practical point of view. Numerical experiments with a multi-scale Lorentz 96 model are conducted to evaluate the performance of these variants against that of the conventional EnKF. In addition, specific for coupled data assimilation problems, two prototypes of extensions of the presented methods are also developed in order to achieve a trade-off between efficiency and accuracy.

Luo, Xiaodong; Hoteit, Ibrahim

2014-12-01

405

Global digital divide: determinants of cross-country ICT development with special reference to Southeast Asia  

Directory of Open Access Journals (Sweden)

Full Text Available Information and communication technology (ICT tools are regarded as imperative not only for enabling the economy to grow at a healthy rate, but also for elevating the socioeconomic conditions and standards of the society. In concurrence with the widespread diffusion of ICT, lies the phenomenon called digital divide – a complex issue pertaining to unequal access, use and applications of ICT among countries and peoples. This paper attempts to measure the contribution of conventional factors such as affordability, infrastructure, trade openness and urbanization, with added emphasis on the role of financial development in explaining cross-country development of ICT among Southeast Asian countries. Using panel data for 4 countries for the period 1994 – 2011, findings of this study revealed that GDP is the most significant determinant in explaining digital divide – consistent with findings from previous research efforts. Financial development also appear significant in most models adopted in all three ICT tools, implying the need for these countries to improve their financial markets to avoid falling further behind in promoting a digitally inclusive society.

Debbra Toria Nipo

2014-09-01

406

Quantum Divided Power Algebra, q-Derivatives and Some New Quantum Groups  

CERN Document Server

The discussions in the present paper arise from exploring intrinsically the structure nature of the quantum $n$-space. A kind of braided category $\\Cal {GB}$ of $\\La$-graded $\\th$-commutative associative algebras over a field $k$ is established. The quantum divided power algebra over $k$ related to the quantum $n$-space is introduced and described as a braided Hopf algebra in $\\Cal {GB}$ (in terms of its 2-cocycle structure), over which the so called special $q$-derivatives are defined so that several new interesting quantum groups, especially, the quantized polynomial algebra in $n$ variables (as the quantized universal enveloping algebra of the abelian Lie algebra of dimension $n$), and the quantum group associated to the quantum $n$-space, are derived from our approach independently of using the $R$-matrix. As a verification of its validity of our discussion, the quantum divided power algebra is equipped with a structure of $U_q(\\frak {sl}_n)$-module algebra via a certain $q$-differential operators realiza...

Hu, Naihong

2009-01-01

407

The public-private divide in household behavior: How far into home can energy guidance reach?  

International Nuclear Information System (INIS)

Environmental problems in the energy system often originate from everyday activities and choices. Everyday activities in the home are part of the private sphere that can be contested in relation to energy policies. This article discusses the public-private divide in energy policies and how Swedish municipal energy consultants understand the divide. By analyzing the actions of energy consultants and their efforts to influence households, as well as how households perceive this guidance, I will discuss the public-private discourse in relation to energy policy and how this discourse can be a restriction for the energy consultants to reach their full potential. The consultants found it problematic to discuss behavioral issues because they did not know how to relate to people's everyday life activities without intruding on private and personal matters. For the households tailored information and feedback was not perceived as the consultant trespassing in the private sphere. Instead, the householders highlight the possibilities of such mapping. Lessoned learned from Sweden is that state subsidies to local energy consultants is a good way to reach households, but that they need to develop their methods and use more tailored information.

408

Information Resources Column: "The Digital Divide: How Wide and How Deep?  

Directory of Open Access Journals (Sweden)

Full Text Available The complexity of the issues that make up the digital divide problem is better understood today. It is no longer sufficient to see it simply as a disparity of access to computer technology. Rather, there is recognition that having meaningful support for using the technology is also an essential ingredient for getting online. The digital divide is a global problem, but even in the technology rich United States the situation is troubling. Recent studies have shown that within the United States, public libraries play a key role in helping the digitally disadvantaged get connected to the Internet and learn how to use it to serve their needs. As more individuals are connected online, those who are not, however, are increasingly in danger for becoming more marginalized within society. Health care professionals need to be aware that they may well be working with individuals who are increasingly outside of the mainstream of the digital revolution and who cannot take advantage of Internet resources that could positively impact their health.

Schloman, B

2004-05-01

409

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 development and support. This research explores all previously mentioned initiatives to suggest how e-Government project in Jordan can empower poor women in rural areas with minimal or no ICT skills, and with no computers or Internet at their homes. This study interviewed fifty women who utilized support from previously mentioned foundations and concluded that e-Government project in Jordan did not reach the required level of service towards helping in bridging the gender divide and help poor women improve their lives. Conclusions and future work are stated at the end.

Boran A. AL-Rababah

2010-01-01

410

Design of K-Band Substrate Integrated Waveguide Coupler, Circulator and Power Divider  

Directory of Open Access Journals (Sweden)

Full Text Available Our study concerns the analysis of K-band passive devices using a new technology, substrate integrated waveguide (SIW, by the HFSS code. This technology has been applied successfully to the conception of planar compact components for the microwave and millimeter waves applications. This application focuses on three components: A coupler junction (-3dB used for routing, dividing and combining the signals in the microwave system. The levels of reflection and isolation below -15dB occupy more than 26.43% of the bandwidth, the insertion loss S21 and coupling S31 fluctuate between -3.24dB and -3.78dB, respectively. The SIW ferrite junction circulator has potential applications in integrated communication and radar systems. Its frequency response shows reflection losses below -15 dB in more than 21.75% of the bandwidth, an insertion loss about -0.65 dB, while the maximum of the isolation is -38.11dB. The T-junction SIW power divider (-3dB indicates that levels of reflection below -15dB occupy more than 26.32% of the bandwidth. The transmission coefficients S21 and S31 are around -3.54dB, showing equal division of the power injected into port 1. In this paper, design considerations and results are discussed and presented.

Bouchra Rahali

2014-01-01

411

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

412

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

413

Metacognition of multitasking: How well do we predict the costs of divided attention?  

Science.gov (United States)

Risky multitasking, such as texting while driving, may occur because people misestimate the costs of divided attention. In two experiments, participants performed a computerized visual-manual tracking task in which they attempted to keep a mouse cursor within a small target that moved erratically around a circular track. They then separately performed an auditory n-back task. After practicing both tasks separately, participants received feedback on their single-task tracking performance and predicted their dual-task tracking performance before finally performing the 2 tasks simultaneously. Most participants correctly predicted reductions in tracking performance under dual-task conditions, with a majority overestimating the costs of dual-tasking. However, the between-subjects correlation between predicted and actual performance decrements was near 0. This combination of results suggests that people do anticipate costs of multitasking, but have little metacognitive insight on the extent to which they are personally vulnerable to the risks of divided attention, relative to other people. PMID:24490818

Finley, Jason R; Benjamin, Aaron S; McCarley, Jason S

2014-06-01

414

Phase space barriers and dividing surfaces in the absence of critical points of the potential energy  

CERN Document Server

We consider the existence of invariant manifolds in phase space governing reaction dynamics in situations where there are no saddle points on the potential energy surface in the relevant regions of configuration space. We point out that such situations occur in a number of important classes of chemical reactions, and we illustrate this concretely by considering a model for transition state switching in an ion-molecule association reaction due to Chesnavich (J. Chem. Phys. {\\bf 84}, 2615 (1986)). For this model we show that, in the region of configuration space relevant to the reaction, there are no saddle points on the potential energy surface, but that in phase space there is a normally hyperbolic invariant manifold (NHIM) bounding a dividing surface having the property that the reactive flux through this dividing surface is a minimum. We then describe two methods for finding NHIMs and their associated phase space structures in systems with more than two degrees-of-freedom. These methods do not rely on the e...

Ezra, Gregory S

2010-01-01

415

The Fermi blazars' divide based on the diagnostic of the SEDs peak frequencies  

CERN Document Server

We have studied the quasi-simultaneous Spectral Energy Distributions (SED) of 48 LBAS blazars, detected within the three months of the LAT Bright AGN Sample (LBAS) data taking period, combining Fermi and Swift data with radio NIR-Optical and hard-X/gamma-ray data. Using these quasi-simultaneous SEDs, sampling both the low and the high energy peak of the blazars broad band emission, we were able to apply a diagnostic tool based on the estimate of the peak frequencies of the synchrotron (S) and Inverse Compton (IC) components. Our analysis shows a Fermi blazars' divide based on the peak frequencies of the SED. The robust result is that the Synchrotron Self Compton (SSC) region divides in two the plane were we plot the peak frequency of the synchrotron SED vs the typical Lorentz factor of the electrons most contributing to the synchrotron emission and to the inverse Compton process. Objects within or below this region, radiating likely via the SSC process, are high-frequency-peaked BL Lac object (HBL), or low/in...

Tramacere, A; Giommi, P; Mazziotta, N; Monte, C

2010-01-01

416

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

417

Subglacial lake matters: piracy on a divide between thawed and frozen bed  

Science.gov (United States)

The two most populated active subglacial lake districts in Antarctica, upper Kamb Ice Stream and lower Whillans Ice Stream, occur along boundaries between where temperature models predict net basal freezing and net basal accretion. This occurs in part due to a basal traction contrast, which creates a ridge in the ice surface and creates a pressure seal; this impedes the downstream movement of water until a subglacial lake flood occurs. Here we use a model for basal water routing, which incorporates subglacial floods and a realistic term for effective pressure, to explore the ability of these floods to provide water to areas of net basal accretion and thus maintain basal lubrication. We hypothesize that these floods can distribute sufficient water to most of the regions experiencing net basal freezing; the exception being those nearest to the lakes themselves, Discharge in these regions likely occurs via narrow subglacial conduits. Over time this will cause ice downstream of the dam to thicken and pre-flood lake levels to increase until water ultimately exits the lake via an alternate route i.e. water piracy. Once piracy occurs, water is no longer supplied along the former flowpath and ice stream shutdown accelerates. We conclude that the formation and quasi-periodic flooding of lakes at the basal melt/ basal freezing boundary is a critical process in accelerating ice stream shutdown.

Carter, S. P.; Bougamont, M. H.; Christoffersen, P.; Fricker, H. A.; Lipscomb, W. H.; Price, S. F.

2011-12-01

418

Effects of nonlinear rheology, temperature and anisotropy on the relationship between age and depth at ice divides  

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Full Text Available Ice flow in divide areas is strongly anisotropic. The evolution of ice fabric, from the onset of divide flow towards steady state with a fully developed fabric, has been shown to profoundly affect both the stratigraphy and surface topography of ice divides. Here, we investigate the effects of ice flow on the age-versus-depth relationship at ice divides by using a full Stokes thermomechanical model with a non-linear anisotropic constitutive relation between stress and strain rates. We compare our results with analytical approximations commonly employed in age–depth predictions, such as the Dansgaard and Lliboutry approximations. We show that these approximations systematically underestimate the age of ice at fully developed divides by as much as one order of magnitude. We also show that divides with fully developed fabric are ideal locations for ice-core extraction because ice under them can be up to one order of magnitude older than ice at the same depth at the flanks. In addition, these divides have a distinctive morphological structure that allows them to be clearly identified from satellite imagery or ground-penetrating radar data.

C. Martín

2012-10-01

419

[Spectral baseline correction by piecewise dividing in Fourier transform infrared gas analysis].  

Science.gov (United States)

Aimed at the problem that baseline drift or distortion often appears in Fourier transform spectra after spectrometer has continuously worked for a long time, baseline variation caused by IR source temperature drift and fluctuation, tilt of moving mirror, performance parameter change of beam splitter and lateral shift of detector were studied by simulating using MATLAB. Simulation results show that spectral baseline drift is approximately linear. On this basis, a novel method named spectral baseline correction by piecewise dividing (SBCPD) is proposed to correct spectral baseline in the present work By comparing peak height of simulated spectra, it was found that performance of SBCPD is better than that of common methods of polynomial fitting, air-PLS (adaptive iteratively reweighted Penalized Least Squares). And the application in gas well-logging showed that prediction accuracy of SBCPD is also higher. Additionally, this method is reliable and of less calculation, and is suitable for engineering application. PMID:23697106

Tang, Xiao-Jun; Wang, Jin; Zhang, Lei; Guan, Jin-Feng; Zhang, Yong; Liu, Jun-Hua

2013-02-01

420

Design of High speed Low Power Reversible Vedic multiplier and Reversible Divider  

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Full Text Available This paper bring out a 32X32 bit reversible Vedic multiplier using "Urdhva Tiryakabhayam" sutra meaning vertical and crosswise, is designed using reversible logic gates, which is the first of its kind. Also in this paper we propose a new reversible unsigned division circuit. This circuit is designed using reversible components like reversible parallel adder, reversible left-shift register, reversible multiplexer, reversible n-bit register with parallel load line. The reversible vedic multiplier and reversible divider modules have been written in Verilog HDL and then synthesized and simulated using Xilinx ISE 9.2i. This reversible vedic multiplier results shows less delay and less power consumption by comparing with array multiplier.

Srikanth G Department of Electronics & Communication Engineerig, Indur Institute of Engineering & Technology, Siddipet, Medak, JNTUH University, Telangana, India.

2014-09-01

421

Microwave Slow-Wave Structure and Phase-Compensation Technique for Microwave Power Divider  

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Full Text Available In this paper, T-shaped electromagnetic bandgap is loaded on a coupled transmission line itself and its electric performance is studied. Results show that microwave slow-wave effect can be enhanced and therefore, size reduction of a transmission-line-based circuit is possible. However, the transmission-line-based circuits characterize varied phase responses against frequency, which becomes a disadvantage where constant phase response is required. Consequently, a phase-compensation technique is further presented and studied. For demonstration purpose, an 8-way coupled-line power divider with 22.5 degree phase shifts between adjacent output ports, based on the studied slow-wave structure and phase-compensation technique, is developed. Results show both compact circuit architecture and improved phase imbalance are realized, confirming the investigated circuit structures and analyzing methodologies.

J. L. Li

2014-04-01

422

Sorbents for radioiodide on the basis of finely divided silver in porous materials  

International Nuclear Information System (INIS)

For the determination of very small radioiodine activities in air a mobile high volume sampler with a charcoal filter bed, and a method for concentrating sorbed radioiodine from the considerable volume of charcoal were developed. Part of the development work was concerned with finding suitable silver containing sorbents. Sorbents that concentrate radioiodide from aqueous alkaline solutions are obtained by depositing finely divided silver in porous materials, in particular in cation exchange resins. Suitable materials and procedures for preparing sorbents with capacities up to about 120 ?mol I- per ml sorbent (i.e. 40 mmol I- per mol Ag) are discussed. The radioiodine activity of the sorbent insert is then determined by gamma spectrometry. (author)

423

Long division unites - long union divides, a model for social network evolution  

CERN Document Server

A remarkable phenomenon in the time evolution of many networks such as cultural, political, national and economic systems, is the recurrent transition between the states of union and division of nodes. In this work, we propose a phenomenological modeling, inspired by the maxim "long union divides and long division unites", in order to investigate the evolutionary characters of these networks composed of the entities whose behaviors are dominated by these two events. The nodes are endowed with quantities such as identity, ingredient, richness (power), openness (connections), age, distance, interaction etc. which determine collectively the evolution in a probabilistic way. Depending on a tunable parameter, the time evolution of this model is mainly an alternative domination of union or division state, with a possible state of final union dominated by one single node.

Jian, Jiang; Michel, Pezeril; Qiuping-Alexandre, Wang

2013-01-01

424

Stickiness in Hamiltonian systems: from sharply divided to hierarchical phase space  

CERN Document Server

We investigate the dynamics of chaotic trajectories in simple yet physically important Hamiltonian systems with non-hierarchical borders between regular and chaotic regions with positive measures. We show that the stickiness to the border of the regular regions in systems with such a sharply divided phase space occurs through one-parameter families of marginally unstable periodic orbits and is characterized by an exponent \\gamma= 2 for the asymptotic power-law decay of the distribution of recurrence times. Generic perturbations lead to systems with hierarchical phase space, where the stickiness is apparently enhanced due to the presence of infinitely many regular islands and Cantori. In this case, we show that the distribution of recurrence times can be composed of a sum of exponentials or a sum of power-laws, depending on the relative contribution of the primary and secondary structures of the hierarchy. Numerical verification of our main results are provided for area-preserving maps, mushroom billiards, and...

Altmann, E G; Kantz, H; Altmann, Eduardo G.; Motter, Adilson E.; Kantz, Holger

2006-01-01

425

Digital Divide: How Do Home Internet Access and Parental Support Affect Student Outcomes?  

Directory of Open Access Journals (Sweden)

Full Text Available This study examined the relationship between home Internet access/parental support and student outcomes. Survey data were collected from 1,576 middle school students in China. Data were analyzed using descriptive analysis, independent-samples T-test, and regression analysis. Results indicate that students who had home Internet access reported higher scores than those without home Internet on all three dimensions: Computer and Internet self-efficacy, Attitudes towards technology and Developmental outcomes. Home Internet access and parental support were significantly positively associated with technology self-efficacy, interest in technology, perceived importance of the Internet, and perceived impact of the Internet on learning. Findings from this study have significant implications for research and practice on how to narrow down the digital divide.

Jing Lei

2012-03-01

426

Review Article: The Master and His Emissary: The Divided Brain and the Western World  

Directory of Open Access Journals (Sweden)

Full Text Available This is a review Iain McGilchrist, The Master and His Emissary: The Divided Brain and the Western World, New Haven and London: Yale University Press, 2010, ix + 534 pp. ISBN: 978-0-300-16892-1 pb, £11.99, $25.00. It argues that through his work in neuroscience, McGilchrist has provided us with the means to comprehend the nihilistic tendencies of Western civilization, how these tendencies emerged and where they are taking us. He shows it to be the consequence of malfunctiong brains. At the same time, through his study of eras when the brain was not malfunctioning while supporting philosophers who recognized what is wrong, he offers us a clearer idea of what civilization should be and how nihilism might be overcome.

Arran Gare

2012-05-01

427

A divide-and-inner product parallel algorithm for polynomial evaluation  

Energy Technology Data Exchange (ETDEWEB)

In this paper, a divide-and-inner product parallel algorithm for evaluating a polynomial of degree N (N+1=KL) on a MIMD computer is presented. It needs 2K + log{sub 2}L steps to evaluate a polynomial of degree N in parallel on L+1 processors (L{<=}2K-2log{sub 2}K) which is a decrease of log{sub 2}L steps as compared with the L-order Homer`s method, and which is a decrease of (2log{sub 2}L){sup 1/2} steps as compared with the some MIMD algorithms. The new algorithm is simple in structure and easy to be realized.

Hu, Jie; Li, Lei [Aomori Univ. (Japan); Nakamura, Tadao [Tohoku Univ., Sendai (Japan)

1994-12-31

428

Bridging the Divide: Tensions Between the Biophysical and Social Sciences in An Interdisciplinary Sustainability Science Project  

Directory of Open Access Journals (Sweden)

Full Text Available Interdisciplinary research has gained tremendous popularity in higher education over the past several decades and funding for such efforts through federal agencies has underscored its relevance. In sustainability science, in particular, interdisciplinarity is seen as integral to the research endeavor. However, a paucity of empirical evidence exists regarding the process of interdisciplinary endeavors, particularly those that cross the social-biophysical science divide. The current study incorporated insights over a four-year period from 25 faculty members involved in a large, interdisciplinary effort at one institution of higher education in the United States. Issues of disciplinary status, power, and hierarchy were prevalent in their accounts. Recommendations for policy and practice are included.

Susan K. Gardner

2014-02-01

429

Wave-front dividing beam combined laser fusion driver using stimulated Brillouin scattering phase conjugation mirrors  

International Nuclear Information System (INIS)

The beam combination method using stimulated Brillouin scattering phase conjugation mirrors (SBS-PCMs) is a promising technique for a commercial laser fusion driver operated with a high repetition rate around 10 Hz. The phase control of the SBS wave is essential for realization of the coherent beam combined output in the beam combination. For this reason, we proposed the 'self-phase control technique' of the stimulated Brillouin scattering wave, and its principle has been demonstrated experimentally over the past several years. In this work, the experiments are performed for the phase stabilization of wave-front dividing two-beam and four-beam combined systems by reducing the beam pointing fluctuation of the laser source using a beam expansion.

430

The exhibition Namibia-Germany: a shared/divided history. Resistance, violence, memory  

Directory of Open Access Journals (Sweden)

Full Text Available The year 2004 was the centenary of the outbreak of a colonial war in former German South West Africa in which thousands of Africans were killed by the colonial power. Although of crucial importance for Namibia, the war had not entered public memory in Germany. The exhibition aimed at presenting colonial history, as well as the contemporary relationships between the two countries, showing a ‘shared’ and a ‘divided’ history. The exhibition created a public debate, which certainly supported the initiative of the German Minister of Economic Co-operation and Development to deliver an apology at the commemoration in August 2004 in Namibia. The article is a post-reflection of one of the co-curators on the exhibition putting it into a larger context and reviewing it concurrently.

Clara Himmelheber

2014-10-01

431

Fitness for service evaluation of cracked divider plate bolt locking tabs for nuclear steam generators  

International Nuclear Information System (INIS)

This paper is to address the structural integrity issues related to continued service without repair or replacement for cracked locking tabs on divider plates of nuclear steam generators. Significantly high residual stress introduced by cold bending of locking tabs at installation was simulated by elastic-plastic finite element method and considered in the fitness for service evaluation. Significant work hardening resulted from the accumulation of large and inhomogeneous plastic deformation introduced by the in situ bending was quantified and considered. Failure and degradation mechanisms for crack stability and propagation were identified. Linear elastic fracture mechanics (LEFM) theory with crack tip plastic zone correction was adopted to establish critical crack sizes. Life of safe operation of the cracked locking tabs from inspected crack sizes to the critical crack sizes was then evaluated. Initial crack sizes at installation were also established through a highly contrived backward fitting evaluation procedure.

432

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 the splitters we have demonstrated that our new polymer based triangular shaped splitter can work simultaneously in broader spectrum, the only condition would be that the waveguides are single-mode guiding. It practically means that, what concerns communication wavelengths, it can on principle simultaneously operate at two mainly used wavelengths, 1310 and 1550 nm.

V. Prajzler

2013-04-01

433

Observation of the limit cycle in the asymmetric plasma divided by the magnetic filter  

International Nuclear Information System (INIS)

Asymmetric plasma divided by the magnetic filter (MF) is numerically simulated by the one-dimensional particle-in-cell code VSIM1D. Depending on the asymmetry, the system behaves static or dynamic. In the static state, the potentials of the main plasma and the sub-plasma are given by the sheath potentials, ?M - 3TMe/e and ?S - 3TSe/e, respectively, with e being an electron charge and TMe and TSe being electron temperatures (TMe > TSe). In the dynamics state, while ?M - 3TMe/e, ?S oscillates periodically between ?S,min - 3TSe/e and ?S,max - 3TMe/e. The ions accelerated by the time varying potential gap get into the sub-plasma and excite the laminar shock waves. This periodic phenomenon can be understood as a limit cycle due to transitions between two bifurcated states of ?S,min and ?S,max. (author)

434

The skill-divide in job quality: a cross-national analysis of 28 countries.  

Science.gov (United States)

This study focuses on the skill divide in job quality and the role of social institutions in structuring the relation of workers' qualifications to the attributes of their jobs. Four measures of job quality are examined: job security, job achievement, job content and work schedule flexibility. The study is based on the 2005 ISSP module on work orientations and encompasses 28 countries. Obtained through multilevel modeling, the findings show that low-skilled workers are disadvantaged in all aspects of job quality. However, skill inequality in the quality of employment depends on countries' characteristics, with declining inequality in countries at higher levels of technological development and to some extent also in times of technological growth. At times of high unemployment, skill disparities in job security widen while on other measures of job quality they decline. Under high market regulation, the low skilled enjoy better job security but on other measures, skill inequalities increase. PMID:25432604

Stier, Haya

2015-01-01

435

Spectroscopic measurements with a silicon drift detector having a continuous implanted drift cathode-voltage divider  

CERN Document Server

A silicon drift detector (SDD) prototype where the drift electrode also plays the role of a high-voltage divider has been realised and characterised for spectroscopic applications at near-room temperatures. Among the advantages of this design, is the absence of metal on the sensitive surface which makes this detector interesting for soft X-rays. The detector prototype has a large sensitive area (2x130 mm sup 2) and the charge is collected by two anodes (butterfly-like detector). The energy resolution of a such a detector has been investigated at near-room temperatures using a commercial, hybrid, low-noise charge-sensitive preamplifier. The results obtained for the X-ray lines from sup 5 sup 5 Fe and sup 2 sup 4 sup 1 Am are presented.

Bonvicini, V; D'Acunto, L; Franck, D; Gregorio, A; Pihet, P; Rashevsky, A; Vacchi, A; Vinogradov, L I; Zampa, N

2000-01-01

436

Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2011 June - September  

Science.gov (United States)

Lightcurves for 28 asteroids were obtained at the Palmer Divide Observatory (PDO) from 2011 June to September: 903 Nealley, 1103 Sequoia, 2052 Tamriko, 2083 Smither, 2150 Nyctimene, 2272 Montezuma, 2306 Bauschinger, 4125 Lew Allen, 5571 Lesliegreen, (7660) 1993 VM1, 7933 Magritte, (16256) 2000 JM2, (16959) 1998 QE17, (17822) 1998 FM135, (18890) 2000 EV26, (27568) 2000 PT6, (31898) 2000 GC1, (32953) 1996 GF19, (32928) 1995 QZ, (33356) 1999 AM3, (35055) 1984 RB, (54234) 2000 JD16, (60365) 2000 AT109, (62117) 2000 RC102, (67404) 2000 PG26, 70030 Margaretmiller, (140428) 2001 TT94, (282081) 2000 NG. Observations of 70030 Margaretmiller indicate that the asteroid is a probable binary with a secondary period being detected but no mutual events.

Warner, Brian D.

2012-01-01

437

Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2009 September-December  

Science.gov (United States)

Lightcurves for 26 asteroids were obtained at the Palmer Divide Observatory (PDO) from 2009 September through December: 298 Baptistina, 546 Herodias, 1355 Magoeba, 1626 Sadeya, 1750 Eckert, 2001 Einstein, 2083 Smither, 3086 Kalbaugh, 4125 Lew Allen, 4531 Asara, 4736 Johnwood, 5230 Asahina, 5841 Stone, 6141 Durda, (6444) 1989 WW, 9739 Powell, 16669 Rionuevo, 24654 Fossett, (29242) 1992 HB4, (29308) 1993 UF1, (31850) 2000 EB22, (37634) 1993 UZ, (38047) 1998 TC3, (40203) 1998 SP27, (218144) 2002 RL66, and NEA 2009 XR2. In addition, data for 1355 Magoeba from 2006 were re-analyzed. The periods derived from the 2006 and 2009 apparitions cannot be reconciled. The solution based on the 2009 data has been adopted as the one more likely correct. For four of the asteroids, 2001 Einstein, 3086 Kalbaugh, 4736 Johnwood, and 5841 Stone, the 2009 data were combined with those from earlier apparitions to derive spin axis and shape models.

Warner, Brian D.

2010-04-01

438

Organelle-based aggregation and retention of damaged proteins in asymmetrically dividing cells.  

Science.gov (United States)

Aggregation of damaged or misfolded proteins is a protective mechanism against proteotoxic stress, abnormalities of which underlie many aging-related diseases. Here, we show that in asymmetrically dividing yeast cells, aggregation of cytosolic misfolded proteins does not occur spontaneously but requires new polypeptide synthesis and is restricted to the surface of ER, which harbors the majority of active translation sites. Protein aggregates formed on ER are frequently also associated with or are later captured by mitochondria, greatly constraining aggregate mobility. During mitosis, aggregates are tethered to well-anchored maternal mitochondria, whereas mitochondria acquired by the bud are largely free of aggregates. Disruption of aggregate-mitochondria association resulted in increased mobility and leakage of mother-accumulated aggregates into the bud. Cells with advanced replicative age exhibit gradual decline of aggregates-mitochondria association, likely contributing to their diminished ability to rejuvenate through asymmetric cell division. PMID:25417105

Zhou, Chuankai; Slaughter, Brian D; Unruh, Jay R; Guo, Fengli; Yu, Zulin; Mickey, Kristen; Narkar, Akshay; Ross, Rhonda Trimble; McClain, Melainia; Li, Rong

2014-10-23

439

Drosophila midgut homeostasis involves neutral competition between symmetrically dividing intestinal stem cells.  

Science.gov (United States)

The Drosophila adult posterior midgut has been identified as a powerful system in which to study mechanisms that control intestinal maintenance, in normal conditions as well as during injury or infection. Early work on this system has established a model of tissue turnover based on the asymmetric division of intestinal stem cells. From the quantitative analysis of clonal fate data, we show that tissue turnover involves the neutral competition of symmetrically dividing stem cells. This competition leads to stem-cell loss and replacement, resulting in neutral drift dynamics of the clonal population. As well as providing new insight into the mechanisms regulating tissue self-renewal, these findings establish intriguing parallels with the mammalian system, and confirm Drosophila as a useful model for studying adult intestinal maintenance. PMID:22522699

de Navascués, Joaquín; Perdigoto, Carolina N; Bian, Yu; Schneider, Markus H; Bardin, Allison J; Martínez-Arias, Alfonso; Simons, Benjamin D

2012-05-30

440

Distributed Memory Programming on Many-Cores : A Case Study Using Eden Divide-&-Conquer Skeletons  

DEFF Research Database (Denmark)

Eden is a parallel extension of the lazy functional language Haskell providing dynamic process creation and automatic data exchange. As a Haskell extension, Eden takes a high-level approach to parallel programming and thereby simplifies parallel program development. The current implementation is tailored to networks of workstations. Recent work has shown that this implementation shows surprisingly competitive performance on many-core machines, compared to dedicated shared-memory implementations of parallel Haskell. In the paper we describe a case study with different Eden divide-and-conquer skeletons. We analyse their performance comparing example applications implemented using these Eden skeletons against parallel Haskell implementations using shared memory on many-core machines

Berthold, Jost; Dieterle, Mischa

2009-01-01

441

Divide and conquer the Hilbert space of translation-symmetric spin systems.  

Science.gov (United States)

Iterative methods that operate with the full Hamiltonian matrix in the untrimmed Hilbert space of a finite system continue to be important tools for the study of one- and two-dimensional quantum spin models, in particular in the presence of frustration. To reach sensible system sizes such numerical calculations heavily depend on the use of symmetries. We describe a divide-and-conquer strategy for implementing translation symmetries of finite spin clusters, which efficiently uses and extends the "sublattice coding" of H. Q. Lin [Phys. Rev. B 42, 6561 (1990)]. With our method, the Hamiltonian matrix can be generated on-the-fly in each matrix vector multiplication, and problem dimensions beyond 10^{11} become accessible. PMID:23679546

Weisse, Alexander

2013-04-01

442

The Divide-and-Conquer Subgoal-Ordering Algorithm for Speeding up Logic Inference  

CERN Document Server

It is common to view programs as a combination of logic and control: the logic part defines what the program must do, the control part -- how to do it. The Logic Programming paradigm was developed with the intention of separating the logic from the control. Recently, extensive research has been conducted on automatic generation of control for logic programs. Only a few of these works considered the issue of automatic generation of control for improving the efficiency of logic programs. In this paper we present a novel algorithm for automatic finding of lowest-cost subgoal orderings. The algorithm works using the divide-and-conquer strategy. The given set of subgoals is partitioned into smaller sets, based on co-occurrence of free variables. The subsets are ordered recursively and merged, yielding a provably optimal order. We experimentally demonstrate the utility of the algorithm by testing it in several domains, and discuss the possibilities of its cooperation with other existing methods.

Ledeniov, O; 10.1613/jair.509

2011-01-01

443

Discriminator/Divider module for anode readout of the TOPAZ Inner Drift Chamber  

International Nuclear Information System (INIS)

The Discriminator/Divider module for anode readout of the TOPAZ Inner Drift Chamber has been developed. A single-span wide-CAMAC module can process 32-channel differential signals from the anode preamplifiers. The module provides two kinds of output signals; one is the ECL differential signal for the drift time measurement with the LeCroy TDC system and the other is the TTL logic signal for triggering with the R? Line Search module. Threshold levels of discriminators can be controlled through the standard CAMAC data way in the input voltage range from 10 mV to 500 mV. Test pulse outputs with variable amplitudes and ±5.2 V power lines are also provided for the preamplifier cards. (author)

444

Natural convection in a diagonally divided square cavity filled with a porous medium  

Energy Technology Data Exchange (ETDEWEB)

The flow and heat transfer in a diagonally divided square cavity by an inclined plate and filled with a porous medium were numerically analyzed in this paper. Vertical walls are kept at isothermal conditions, while horizontal walls are insulated. A finite difference scheme was used to solve the dimensionless governing partial differential equations along with the corresponding boundary conditions. Computations were carried out to examine the effects of Rayleigh number (100 {<=} Ra {<=} 1000), thermal conductivity ratio between plate and fluid (0.1 {<=} k {<=} 10) and the position of the partition (45 deg., Case I and 135 deg., Case II). It was found that heat transfer is attenuated when the plate is positioned at 45 deg., the heat transfer is less than when it is at 135 deg.. (authors)

Varol, Y.; Oztop, H.F. [Firat Univ., Dept. of Mechanical Education, Elazig (Turkey); Pop, I. [Cluj Univ., Faculty of Mathematics (Romania)

2009-07-15

445

Competency in network use as a resource for citizenship: implications for the digital divide  

Directory of Open Access Journals (Sweden)

Full Text Available Conceptual and empirical issues of citizens' network ompetency are explored, defined as people's capabilities to use the Internet in order to communicate and seek information and to utilize electronic public services. First, the concept of network competency is discussed. Second, based on an empirical case study conducted in Finland, perceived network competency is explored as a resource for autonomous and participatory citizenship. Perceived network competency refers to the self-rated assessment made by the informants. A high degree of perceived network competency correlated positively with success in work life. Network competent people participated more frequently in the activities of civic organizations and contacted decision-makers. Compared to less competent people, they appeared to be informed consumers. Those with high perceived competency believed that people's opportunities to influence social issues will increase in the future. The findings are explored with regard to the digital divide vs. digital inclusion, discussing the prospects for future research.

Jääskeläinen

2003-01-01

446

Thymoquinone causes multiple effects, including cell death, on dividing plant cells.  

Science.gov (United States)

Thymoquinone (TQ) is a major constituent of Nigella sativa oil with reported anti-oxidative activity and anti-inflammatory activity in animal cells. It also inhibits proliferation and induces programmed cell death (apoptosis) in human skin cancer cells. The present study sought to detect the influence of TQ on dividing cells of three plant systems and on expression of Bcl2-associated athanogene-like (BAG-like) genes that might be involved during the process of cell death. BAG genes are known for the regulation of diverse physiological processes in animals, including apoptosis, tumorigenesis, stress responses, and cell division. Synthetic TQ at 0.1mg/mL greatly reduced wheat seed germination rate, whereas 0.2mg/mL completely inhibited germination. An Evans blue assay revealed moderate cell death in the meristematic zone of Glycine max roots after 1h of TQ treatment (0.2mg/mL), with severe cell death occurring in this zone after 2h of treatment. Light microscopy of TQ-treated (0.2mg/mL) onion hairy root tips for 1h revealed anti-mitotic activity and also cell death-associated changes, including nuclear membrane disruption and nuclear fragmentation. Transmission electron microscopy of TQ-treated cells (0.2mg/mL) for 1h revealed shrinkage of the plasma membrane, leakage of cell lysate, degradation of cell walls, enlargement of vacuoles and condensation of nuclei. Expression of one BAG-like gene, previously associated with cell death, was induced 20 min after TQ treatment in Glycine max root tip cells. Thus, TQ has multiple effects, including cell death, on dividing plant cells and plants may serve as a useful system to further investigate the mechanisms underlying the response of eukaryotic cells to TQ. PMID:24296078

Hassanien, Sameh E; Ramadan, Ahmed M; Azeiz, Ahmed Z Abdel; Mohammed, Rasha A; Hassan, Sabah M; Shokry, Ahmed M; Atef, Ahmed; Kamal, Khalid B H; Rabah, Samar; Sabir, Jamal S M; Abuzinadah, Osama A; El-Domyati, Fotouh M; Martin, Gregory B; Bahieldin, Ahmed

2013-01-01

447

Cor triatriatum or divided atriums: which approach provides the better understanding?  

Science.gov (United States)

It is frequent, in the current era, to encounter congenital cardiac malformations described in terms of "cor triatriatum". But can hearts be truly found with three atrial chambers? The morphological method, emphasised by Van Praagh et al, states that structures within the heart should be defined on the basis of their most constant components. In the atrial chambers, it is the appendages that are the most constant components, and to the best of our knowledge, hearts can only possess two appendages, which can be of either right or left morphology. The hearts described on the basis of "cor triatriatum", nonetheless, can also be analysed on the basis of division of either the morphologically right or the morphologically left atriums. In this review, we provide a description of cardiac embryology, showing how each of the atrial chambers possesses part of the embryological body, along with an appendage, a vestibule, a venous component, and a septum that separates them. We then show how it is, indeed, the case that the hearts described in terms of "cor triatriatum" can be readily understood on the basis of division of these atrial components. In the right atrium, it is the venous valves that divide the chamber. In the left atrium, it is harder to provide an explanation for the shelf that produces atrial division. We also contrast the classic examples of the divided atrial chambers with the vestibular shelf that produces supravalvar stenosis in the morphologically left atrium, showing that this form of obstruction needs to be distinguished from the fibrous shelves producing intravalvar obstruction. PMID:24820379

Bharucha, Tara; Spicer, Diane E; Mohun, Timothy J; Black, David; Henry, G William; Anderson, Robert H

2014-05-13

448

Development and Field Evaluation of a Rotary Hydraulic Divider for Canola Harvesting  

Directory of Open Access Journals (Sweden)

Full Text Available Oil seed rape is an important non-cereal crop used mainly for edible oil production. Canola pods are fragile and its branches are twisted together at harvesting time. Harvesting with a conventional combine can pull off twisted branches and cause appreciable losses in the vicinity of divider at combine header. In this study, a hydraulic rotary divider was designed and developed to separate twisted pods and reduce the grain loss. The device is made up of two cylinders and a number of fingers, the cylinders rotate in opposite direction and fingers move in and out through holes on cylinder walls. The assembly was expected to separate the twisted pods and reduce grain loss. A hydraulic motor driven by combine hydraulic system was used to rotate the separating cylinders. The separating assembly was installed on righthand side of the combine harvester header. A split-plot experiment was used to evaluate the performance of the unit. Field tests were carried out at combine forward speed of 1.5 kmh-1. Variables were: cylinders rotary speed in three levels (50, 75 and 100 rpm, the number of fingers in three levels (16, 12 and 8, and the tests were conducted with and without combine reel. Two different positions of finger protrusion were also considered in field tests. The results were compared with those of a conventional combine header. The results show that the medium rotational speed (75 rpm exhibited lowest seed loss. Furthermore, as the number of fingers increased, the seed loss tended to decrease. The seed loss also decreased in the presence of combine reel. Also, findings showed there is no significant difference between the two protrusions trajectories of fingers. A twenty percent decrease in seed loss was observed at rotary speed of 75 rpm and number of fingers of 16 in the presence of combine reel.

Kamgar

2009-04-01

449

Social suffering and the culture of compassion in a morally divided China.  

Science.gov (United States)

This collection of essays opens a critical examination of compassionate acts responding to social suffering in the intensely complex moral context of a rapidly changing and globalizing China. Jeanne Shea describes self-compassion among older women in China as a post-revolutionary response to changing opportunities and resistance to consumerism. Khun Eng Kuah-Pearce's essay frames the Buddhist organizations as NGOs and shows compassion being mobilized and its acts being spiritual-philanthropic, not political. The next three papers illuminate the complexity of mobility in a moral sea of changing values. Even as modernity facilitates movement of people away from suffering, the grinding of entangled moral experiences within the mobile group can be the cause of suffering. Shu-Min Huang critiques 'cultural petrification' as the diasporic Yunnan Chinese community in Thailand attempt to preserve the cultural forms and procedures of the world they left behind. Likewise, Richard Madsen shows that the idea of a universalized cultural heritage fails in the face of the 'micro-ecologies'. And yet the modern impulse to universalize beyond China has important implications for transnational compassion and cooperation. The work of the humanitarian organization Médecins Sans Frontières in China, discussed by Kuah-Pearce and Guiheux, challenges the universality of global humanitarian actions. Following the series of essays threaded across intersections of compassion, suffering, and a morally-divided China, the collection closes by looking at the West. Iain Wilkinson discusses the origins of social suffering as a focus of the social sciences, as well as the difficulties of making engaged compassion its task in a morally-divided world. PMID:24524752

Kuah-Pearce, Khun Eng; Kleinman, Arthur; Harrison, Emily

2014-01-01

450

Magnetized Water and Memory Meter  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents an experimental study to investigate the effect of using the magnetic water conditioner on the properties of water. The water flows through a closed loop, while the pH, TDS, and hardness represent its properties. For magnetic water conditioner with flux density of 170 mT, results showed that pH increased by 15.65% for 820 minutes of non-stop circulation. The increase in pH is divided to 93.5% for the first 360 minutes, and 6.5% for the last 460 minutes. TDS and Hardness of water are not affected by the magnetic water conditioner. Water remembers and keeps the impact of passing through the magnetic field for several hours, and pH decreased by 0.642 in24 hours. While the results lead to introduce and create the magnetized water saturation curve and water memory meter.

Ashraf Kotb

2013-08-01

451

76 FR 21855 - Rio Grande National Forest, Divide Ranger District; Mineral County, CO; Village at Wolf Creek...  

Science.gov (United States)

...DEPARTMENT OF AGRICULTURE Forest Service Rio Grande National Forest, Divide Ranger District...SUMMARY: The Rio Grande National Forest is preparing an Environmental...and April 27 in Del Norte at the Rio Grande County Annex Building, CO....

2011-04-19

452

5 CFR Appendix A to Subpart J of... - Guidelines for Interpreting State Court Orders Dividing Civil Service Retirement Benefits  

Science.gov (United States)

...State Court Orders Dividing Civil Service Retirement Benefits A Appendix A to Subpart...CONTINUED) COURT ORDERS AFFECTING RETIREMENT BENEFITS Court Orders Affecting Civil Service Retirement Benefits Pt. 838, Subpt. J,...

2010-01-01

453

TRILOGY- ANCIENT AGE, MIDDLE AGE AND NEW AGE- IN THE DIVIDING HISTORY INTO AGES AND THE EUROCENTRIC HISTORY CONSTRUCTION  

OpenAIRE

one of the most significant paradigms or preassumptions of the science of history. Both academic and amateur historians are dividing historical period into Ancient Age, Middle Age and New Age by starting from these preassumptions. Professional specializations in the field of history are being prepared according to this, too.The three system which became common part of the human history was constituted in a long period. Aurelius Augustinus (354-4309), the father of Catholic Church, divided his...

Alkan, Necmettin

2009-01-01

454

A High-Voltage Test Bed for the Evaluation of High-Voltage Dividers for Pulsed Applications  

CERN Document Server

The design, evaluation, and commissioning of a high-voltage reference test bed for pulsed applications to be used in the precision testing of high-voltage dividers is described. The test bed is composed of a pulsed power supply, a reference divider based on compressed-gas capacitor technology, and an acquisition system that makes use of the fast measurement capabilities of the HP3458 digital voltmeter. The results of the evaluation of the reference system are presented.

Bastos, M C; Hammarquist, M

2011-01-01

455

The digital divide in Internet information searching: A double-hurdle model analysis of household data from Vermont  

OpenAIRE

While most studies on the digital divide in the United States focus on disparities in access to computers and the Internet, this study examines the digital divide in Internet information searching. With data from 476 Vermont households surveyed in 2009, a double-hurdle model is used to identify the factors that impact the likelihood and frequency of using the Internet for information searching. Empirical results suggest that there are significant disparities in both the likelihood and frequen...

Zhang, Guangxuan University Of Vermont; Wang, Qingbin; Kolodinsky, Jane

2010-01-01

456

Information and Communication Technologies and the Digital Divide in Africa: A Review of the Periodical Literature, 2000-2012  

Directory of Open Access Journals (Sweden)

Full Text Available The digital revolution has transformed much of the global economy. Information and communication technologies (ICTs play a key role in this revolution. However, not everyone has equal access to these technologies. This gap exists on multiple levels, whether between individuals, small segments within a population, countries, or global regions. The term used to refer to this inequality is the digital divide. This bibliography focuses on recent literature written to describe the digital divide on the African continent.

Susan E. Russell

2013-04-01

457

Oligocene - early Miocene evolution of the Western Alps drainage divide: constraints from multidisciplinary provenance analysis  

Science.gov (United States)

The uplift of the Western Alps mountain range since the Oligocene is driven by the collision between the Apulian and European plates. The corresponding exhumation history was often reconstructed by considering detrital thermochronology data alone. Here we present the results of a multidisciplinary approach for constraining the position of the drainage divide in the southern Western Alps during the early Oligocene to early Miocene. We traced sediment provenance and exhumation rates preserved in the pro-side (Montmaur and Barrême) and retro-side (Torino hills) foreland basins, using geochemical and petrological analyses, and detrital geo-thermochronology (U-Pb and fission-track analyses). Major and trace-element analyses of basalt pebbles, as well as Raman spectroscopy of serpentinite sand grains and pebbles, allow the identification of potential source lithologies in the internal Western Alps, which are not easily detected with detrital thermochronology. Lower Oligocene sediments of the pro-side foreland basin contain numerous basalt pebbles that share strong geochemical similarities with the Chenaillet obducted ophiolite. Raman analysis on serpentine from the pro and retro-side foreland basin deposits documents a systematic trend from antigorite (high-grade metamorphic conditions) to lizardite (low-grade metamorphic conditions) from the early Oligocene to the early Miocene. This trend is attributed to a shift in the location of the drainage divide in the Western Alps. Ophiolite erosion and drainage divide shift strongly constrain any reconstruction of the topographic evolution of the Western Alps. Fission-track analysis on detrital zircon and apatite from pro-side samples show that these grains were mainly derived from the internal Alps. Some zircons have fission-track cooling ages close to their depositional age, which could be related either to very fast exhumation of the source zone during the Rupelian, or to the contribution of zircons from contemporary andesitic volcanism. Fission-track/U-Pb double-dating of individual zircons allows identifying the volcanic contribution, as volcanic zircons having Oligocene U-Pb crystallization and fission-track cooling ages. This contribution is small, so that the signal of exhumation at a rate of 1.4 to 2.7 km/Myr of the internal Western Alps during the Oligocene to Miocene is persistent. Recent numerical model show that slab retreat can be consecutive to a slab break off and permit asthenospheric inflow above sudbucting plate. We propose that in Western Alps Oligocene slab break off generate the Oligocene andesitic volcanism then slab retreat. Slab retreat allows the emplacement of the Ivrea body above the European slab. Slab retreat can also cause a diminution of strain in the Western Alps. Erosion and incision of the uplifted surface of the internal Western Alps was probably controlled by fast exhumation in front of the Ivrea mantle indenter. The rapid uplift recorded in the Oligo-Miocene sediments can be interpreted as the consequence of the vertical and forward indentation of the Ivrea mantle sliver.

Jourdan, S. P.; Bernet, M. B.; Dumont, T. D.; Guillot, S. G.; Schwartz, S. S.; Tricart, P. T.

2012-04-01

458

Treatment of multiple brain metastases with a divide-and-conquer spatial fractionation radiosurgery approach.  

Science.gov (United States)

Brain metastases are a common problem, managed with surgery, stereotactic radiosurgery (SRS), whole brain irradiation (WBI), or a combination. SRS targets individual tumors with large dosages of radiation. There is a trend toward using more SRS and less WBI, due to a reduction in cognitive damage, shorter treatment course, and improved tumor control. In conventional radiation a total dose of radiation is frequently divided over time into several smaller "fractions", which helps spare normal tissues such as the brain. Two doses of 10 Gy each given on separate days will result in 45% less damage to normal brain tissue than a single dose of 20 Gy, according to the linear quadratic model for biologically effective dose (BED). Unfortunately, standard fractionation also reduces the effective dose to the tumor. It would therefore be highly beneficial to be able to fractionate the dose to the normal brain, but not fractionate the tumor dose. When a tumor is irradiated, there are dozens of beams that pass through the skull and converge on the tumor, also irradiating healthy brain tissue in the beam paths. If multiple tumors are irradiated, there are areas of brain that are overlapped by beams that are targeting separate tumors. If these tumors were treated on separate days, then on any given day portions of normal brain may only see the radiation beams for one tumor instead of 2 or more. That is how spatial fractionation of multiple metastases works. By treating groups of tumors on separate days the beams are spread out over time, reducing areas of beam overlap, and effectively fractionating the dose to healthy brain. Yet, each tumor still receives a single treatment. The hypothesis is that an array of metastases may be divided into 2-5 different groups that are treated on different days such that the BED to normal brain tissue is minimized. This should benefit patients by reducing side effects, allowing greater numbers of tumors to be treated, and making retreatment safer. An algorithm is discussed, which places the largest tumors and tumors situated close together into different groups. Modifications for axial beam delivery systems such as helical tomotherapy are discussed. PMID:25175716

Kelly, Douglas A

2014-10-01

459