WorldWideScience

Sample records for water resistor divider

  1. Power Rating Measurement of the Voltage Divider Resistors for the Klystron Modulating Anode

    International Nuclear Information System (INIS)

    The 20MeV Proton Linear Accelerator is driven by two of klystrons. The electron gun of the klystrons is triode type with modulating anode. The resistors for voltage divider of modulating anode were installed at supporter including the insulators next to klystrons. The voltage dividing resistors for the klystron at the 20MeV proton linear accelerator are composed of the resistor of five of 1M?, two of 0.5M?. These resistors are exposed to the air very bulky whose length is about 1m. To improve the voltage dividing resistor, the resistor will be in the oil tank of heat cathode. For putting in the oil tank of heat cathode, the size and properties of matter of the resistor must be small in former thing and durable about the oil. In addition, it is important to confirm the power rating of resistor because of reducing the power rating about reducing the dimension. The characteristics of resistor are shown in the Table1

  2. Voltage Divider

    Science.gov (United States)

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

  3. Resistor holder

    International Nuclear Information System (INIS)

    This patent describes a resistor device for use with an electrostatic particle accelerator having apertured axially spaced apart electrode plates and annular insulators, each insulator being positioned between a pair of electrode plates. It comprises an elongate tubular housing formed of electrically conductive material, fixed end cap formed of conductive material and being connected to one end of the tubular housing, movable end cap formed of conductive material spaced radially inwardly and projecting interiorly of the tubular housing at the other end of the latter, and elongate cylindrical resistor element, means engaging the resistor element and positioning the latter in inwardly spaced concentric relation within the tubular housing, resilient means in the tubular housing engaging the fixed end cap and the resistor element for permitting yieldable axial movement of the latter relative to the housing, an annular conducting element electrically connected to the other end of the tubular housing and being spaced radially outwardly of the movable cap and defining an annular spark gap with the latter, and means electrically connecting the ends of the resistor element with the movable fixed end caps

  4. Bridging divides for water? Dialogue and access at the 5th World Water Forum

    OpenAIRE

    Nícola Ulibarrí

    2011-01-01

    The 5th World Water Forum was officially presented as a deliberative democracy where diverse stakeholders could gather to talk about water. However, the conference was marred by significant conflict, ranging from audience complaints to protests, and to alternative political declarations. This paper explores why a Forum designed to 'Bridge Divides for Water' (the official theme) was so contentious that participants were unable to reach any sort of consensus. I explore four hypothesised mechani...

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

    International Nuclear Information System (INIS)

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

  6. Breakdown voltage of metal-oxide resistors in liquid argon

    OpenAIRE

    Bagby, L. F.; Gollapinni, S.; James, C. C.; Jones, B. J. P.; Jostlein, H.; Lockwitz, S.; Naples, D.; Raaf, J. L.; Rameika, R; Schukraft, A.(III. Physikalisches Institut, RWTH Aachen University, 52056 , Aachen, Germany); Strauss, T.; Weber, M. S.; Wolbers, S. A.

    2014-01-01

    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. This test mimics the situation in a HV-divider chain when a breakdown occurs and the voltage across resistors rapidly rise from the static value to much higher values. All resistors had higher breakdown voltages in liquid argon than their vendor ratings in air at room temperature. Failure modes range from full de...

  7. Bridging divides for water? Dialogue and access at the 5th World Water Forum

    Directory of Open Access Journals (Sweden)

    Nícola Ulibarrí

    2011-10-01

    Full Text Available The 5th World Water Forum was officially presented as a deliberative democracy where diverse stakeholders could gather to talk about water. However, the conference was marred by significant conflict, ranging from audience complaints to protests, and to alternative political declarations. This paper explores why a Forum designed to 'Bridge Divides for Water' (the official theme was so contentious that participants were unable to reach any sort of consensus. I explore four hypothesised mechanisms by which the Forum itself counteracted the possibility of Bridging Divides and creating constructive dialogue. First, I argue that, because of cost, security and size, the Forum made many participants feel unable to fully access the Forum and share their opinions. Second, I suggest that the programmatic structure of the Forum promoted simplified ways of talking about water that made translation between perspectives difficult. Third, I contend that the physical space where Forum deliberations occurred institutionalised unequal social arrangements, making certain viewpoints more audible than others. Fourth, I demonstrate that the Turkish host government actively masked contestation to present a 'civilised' Forum to the world.

  8. Resistor coupled Josephson logic

    International Nuclear Information System (INIS)

    A resistor coupled Josephson logic (RCJL) family, composed of OR, AND, and 2/3 majority gates, is proposed. The RCJL family consists of multiple Josephson junctions and resistors, and employs current injected switching. OR gates have I-O isolation capability with high input sensitivity and wide operating current margin. In the AND gate, current margin as wide as the CIL AND gate and higher input sensitivity can be achieved without inductors. Experimental verification of the RCJL family operation is also described

  9. Using Ohm's Law to Build a Voltage Divider

    Science.gov (United States)

    IEEE

    2014-05-23

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

  10. Breakdown voltage of metal-oxide resistors in liquid argon

    CERN Document Server

    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

    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.

  11. Application to printed resistors

    International Nuclear Information System (INIS)

    Most of printed circuit boards are made at present by etching copper foils which are laminated on insulating composite boards of paper/phenol resin or glass nonwoven fabric/epoxy rein. This is called subtractive process, and since this is a wet process, the problem of coping with the pollution due to etching solution, plating solution and others is involved. As the method of solving this problem, attention has been paid to the dry process which forms conductor patterns by screen printing using electro-conductive paste. For such resin substrates, generally polymer thick films (PTF) using thermosetting resin as the binder are used. Also the research on the formation of resistors, condensers and other parts by printing using the technology of cermet thick films (CTF) and PTF is active, and it is partially put in practical use. The problems are the deformation and deterioration of substrates, therefore, as the countermeasures, electron beam hardening type PTF has been studied, and various pastes have been developed. In this paper, electron beam hardening type printed resistors are reported. The features, resistance paste, and a number of the experiments on printed resistors are described. (K.I.)

  12. Breakdown voltage of metal-oxide resistors in liquid argon

    International Nuclear Information System (INIS)

    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. This test mimics the situation in a HV-divider chain when a breakdown occurs and the voltage across resistors rapidly rise from the static value to much higher values. 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

  13. Resistor network for linearity check of voltage ratio meters by combinatorial calibration technique

    Science.gov (United States)

    Hiti, M.

    2015-05-01

    This article describes a resistor network for linearity verification of voltage ratio-indicating instruments. The network is based on a resistive divider with low variation of input and output resistance. To compensate for the output resistance change due to a selection of various output ratios, a switched variable compensating resistor network is added to the output leads of the voltage divider. It limits the variation of output resistance to check of a high-precision strain gauge amplifier.

  14. For current viewing resistor loads

    Science.gov (United States)

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

    2011-04-19

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

  15. Remote Experiments in Resistor Measurement

    Directory of Open Access Journals (Sweden)

    Popescu Viorel

    2009-10-01

    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.

  16. MOS integrated circuits with implanted resistor elements

    International Nuclear Information System (INIS)

    Resistor elements for mos integrated circuits are made by an ion implant step compatable with a self-aligned N-channel silicongate process. The resistor elements are beneath the field oxide in the finished device, although the implant step is prior to formation of the thick oxide. Resistors of this type are ideally suited for load devices in static ram cells

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

    Science.gov (United States)

    Miles, B.; Band, L. E.

    2013-12-01

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

  18. Continental divide

    International Nuclear Information System (INIS)

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

  19. Effect of a divided wetwell on heat removal capability of the water wall type passive capability of the water wall type passive containment cooling system

    International Nuclear Information System (INIS)

    A water wall type containment cooling system, which has a colling pool outside the suppression pool, is one of the passive containment cooling systems (PCCSs). To improve its heat removel capability, we have proposed a divided wetwell (gas phase space in the suppression chamber), which separates the wetwell space into a high steam partial pressure region (first wetwell) and high noncondensable gas partial pressure region (second wetwell). We experimentally examined the thermal hydraulic behavior of the wall type PCCS which applies the divided wetwell. By cooling the second wetwell and condensing the steams which flowed from the first wetwell into the second wetwell, noncondensable gas in the first wetwell was discharged to the second wetwell. In the first wetwell, the saturated steam pressure increased. After the noncondensable gas was fully discharged to the second wetwell, the first wetwell temperature came within 1degC of the suppression pool surface temperature. Therefore, attainable temperatures of the first wetwell and the suppression pool water increased for the same pressure of the primary containment vessel. Consequently, the time-integrated released heat to the outer pool was 70% larger than the non-divided case due to increase of the temperature difference between the suppression pool and outer pool. (author)

  20. Design of a Compact Dump Resistor System for LCD Magnet

    CERN Document Server

    Gaddi, A

    2010-01-01

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

  1. Dividing steam-water annular flow in T-junctions with horizontal inlet and downwardly inclined branch

    International Nuclear Information System (INIS)

    Experimental data on dividing steam-water two-phase annular flow in T-junctions having downwardly inclined branches were obtained. The experiments were performed under high inlet mass flux conditions which had not been examined before. The data covered the inlet mass flux and inlet quality ranges 600 1 2.s and 0.02 1 < 0.08. The branch orientation was found to be a significant parameter affecting phase separation under the present test conditions. This is caused by the non-uniform angular distributions of the liquid film thickness associated with the horizontal inlet annular flow. The pressure changes of two-phase flow in the junction were closely correlated with the phase separation phenomenon. The effect of branch orientation on junction pressure changes was only important in the range of flow split ratio before total phase separation took place. The data on pressure rise in the run and pressure drop in the junction were correlated using simple models based on momentum and mechanical energy balance. 19 refs., 14 figs

  2. 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.

  3. Thermal resistor based on the compensated silicon

    International Nuclear Information System (INIS)

    Full text: The aim of this work is to develop the method for obtaining of compensated silicon single crystals with homogeneous radial distribution of specific resistance for making stable thermal resistors with reproducible parameters including T?100 degrees Celsius. It is known that high resistance materials, such as compensated silicon single crystal are used in most cases for increasing the sensitivity of semiconductor detectors

  4. Characterization of feedback resistors for cryogenic applications

    Science.gov (United States)

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

    1989-01-01

    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.

  5. Rational and irrational numbers from unit resistors

    International Nuclear Information System (INIS)

    We address the problem of constructing a network of unit resistors such that it enables the retrieval of an arbitrary value of equivalent resistance. In particular, we employ the notion of continued fractions to construct a ladder network by which we can easily obtain any fractional value resistance. In addition, since any irrational number is associated with an infinite continued fraction, we discuss the convergence of the equivalent resistance of an infinite resistive ladder and various aspects concerning the approximations of arbitrary numbers attained by adding additional resistors successively to the network. The presented methods can be easily implemented in an educational laboratory and offer an interesting addition to the topic of Ohm’s law. (paper)

  6. Dynamic analysis on the closing resistors of Gas Insulated Switchgear

    International Nuclear Information System (INIS)

    GIS (Gas Insulated Switchgear) is used in electric power system to insure non conductivity, breaking capacity and operating reliability. In the present study, dynamic analysis on the closing resistors of the GIS has bees carried out by the commercial dynamic analysis code COSMOS MOTION and 3-D modeling program SOLID WORKS. In order to find the minimum value of chatter vibration of closing resistors, the motion of moving and fixed resistor parts of closing resistors were simulated by varying the spring constant, the damping coefficient and the mass of moving and fixed resistor parts. The simulated results were compared with experimental results. The application of the results could reduce chatter vibration of closing resistors of the GIS. These data are also useful on the development of future model GIS with minimum chatter vibration for the determinations of the spring constant, the damping coefficient and mass of a moving part

  7. 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)

  8. Continental Divide Trail

    Earth Data Analysis Center, University of New Mexico — This shapefile was created to show the proximity of the Continental Divide to the Continental Divide National Scenic Trail in New Mexico. This work was done as part...

  9. Design of versatile printed organic resistor based on resistivity (?) control

    Science.gov (United States)

    Ali, Shawkat; Bae, Jinho; Lee, Chong Hyun

    2015-04-01

    We demonstrate the design and fabrication of a printed organic resistor based on resistivity (?) control method. Two types of resistor are reported by utilizing three types of material poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), poly(methyl methacrylate), and silver (Ag) nano-particles. Materials are blended for the required value of resistivity (?), to overcome the size and resistance value constraints of the printed resistors. The design function ?(x) is also proposed to estimate the required resistivity value, and this function is obtained from the measured resistivity and mixing ratio of materials. The proposed resistivity design function is verified by comparing measured and theoretical estimated values of the resistivity. The resistors are fabricated on polyethylene terephthalate substrate through electro-hydrodynamic technique. The proposed two types of organic resistors are electrically and mechanically characterized by using various methods of their current-voltage (I-V) relation analysis, endurance time, bendability, heating temperature analysis, and frequency response.

  10. Design of versatile printed organic resistor based on resistivity ( ?) control

    Science.gov (United States)

    Ali, Shawkat; Bae, Jinho; Lee, Chong Hyun

    2015-06-01

    We demonstrate the design and fabrication of a printed organic resistor based on resistivity ( ?) control method. Two types of resistor are reported by utilizing three types of material poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), poly(methyl methacrylate), and silver (Ag) nano-particles. Materials are blended for the required value of resistivity ( ?), to overcome the size and resistance value constraints of the printed resistors. The design function ?( x) is also proposed to estimate the required resistivity value, and this function is obtained from the measured resistivity and mixing ratio of materials. The proposed resistivity design function is verified by comparing measured and theoretical estimated values of the resistivity. The resistors are fabricated on polyethylene terephthalate substrate through electro-hydrodynamic technique. The proposed two types of organic resistors are electrically and mechanically characterized by using various methods of their current-voltage ( I- V) relation analysis, endurance time, bendability, heating temperature analysis, and frequency response.

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

    Science.gov (United States)

    Pfister, Hans

    2014-05-01

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

  12. Scaling in small-world resistor networks

    International Nuclear Information System (INIS)

    We study the effective resistance of small-world resistor networks. Utilizing recent analytic results for the propagator of the Edwards-Wilkinson process on small-world networks, we obtain the asymptotic behavior of the disorder-averaged two-point resistance in the large system-size limit. We find that the small-world structure suppresses large network resistances: both the average resistance and its standard deviation approaches a finite value in the large system-size limit for any non-zero density of random links. We also consider a scenario where the link conductance decays as a power of the length of the random links, l-?. In this case we find that the average effective system resistance diverges for any non-zero value of ?

  13. Divide and Conquer

    OpenAIRE

    POSNER, Eric A; Spier, Kathryn E.; Vermeule, Cornelius Adrian

    2010-01-01

    The maxim “divide and conquer” (divide et impera) is invoked frequently in law, history, and politics, but often in a loose or undertheorized way. We suggest that the maxim is a placeholder for a complex of ideas related by a family resemblance, but differing in their details, mechanisms and implications. We provide an analytic taxonomy of divide and conquer mechanisms in the settings of a Stag Hunt Game and an indefinitely-repeated Prisoners' Dilemma. A number of applications are considered,...

  14. ¿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)

    Carmen, Maganda.

    2008-06-01

    Full Text Available 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.

  15. NuMI Proton Kicker Extraction Magnet Termination Resistor System

    CERN Document Server

    Reeves, Scott

    2005-01-01

    The temperature stability of the kicker magnet termination resistor assembly directly affects the field flatness and amplitude stability of the kick. Comprehensive thermal enhancements were made to the existing Main Injector resistor assembly design to satisfy NuMI performance specifications. Additionally, a fluid-processing system utilizing Fluorinert® FC-77 high-voltage dielectric was built to precisely control the setpoint temperature of the resistor assembly from 70 to 120F, required to maintain constant resistance during changing operational modes. The Fluorinert® must be continually processed to remove hazardous breakdown products caused by radiation exposure to prevent chemical attack of system components. Design details of the termination resistor assembly and Fluorinert® processing system are described. Early performance results will be presented.

  16. Formation of thin-film resistors on silicon substrates

    Science.gov (United States)

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

    1988-11-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bernardini, R. [Centro TEAM, Consorzio Pisa ricerche, Pisa (Italy); Diligenti, A.; Nannini, A.; Piotto, M. [Univ. Pisa (Italy). Dip. Ingegneria dell`Informazione

    1998-07-01

    A simple process to obtain silicon planes released from the substrate and provided with large area pads for ohmic contacts is described. Resistors 500 {mu}m long with a 40 {mu}m x 1 {mu}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.

  18. 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

  19. Resistor Loaded EBG Surfaces for Slot Antenna Design

    OpenAIRE

    Shenyi Cao; Yunqi Fu

    2013-01-01

    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 su...

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

    CERN Document Server

    Kolek, A; Dziedzic, A

    2003-01-01

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

  1. Dividing Rational Numbers

    Science.gov (United States)

    Ms. Nielsen

    2008-09-02

    Students will use rational numbers (i.e. multi-digit, decimals, and fractions) in order to complete a variety of division problems. State of Utah Core Curriculum: Standard 1 Objective 6 Demonstrate proficiency with the four operations, with positive rational numbers, and with addition and subtraction of integers. a. Multiply and divide a multi-digit number by a two-digit number, including decimals. b. Add, subtract, multiply, and divide fractions and mixed numbers. c. Add and subtract integers. Attachments Decimal ...

  2. The Open Access Divide

    OpenAIRE

    Jingfeng Xia

    2013-01-01

    This paper is an attempt to review various aspects of the open access divide regarding the difference between those academics who support free sharing of data and scholarly output and those academics who do not. It provides a structured description by adopting the Ws doctrines emphasizing such questions as who, what, when, where and why for information-gathering. Using measurable variables to define a common expression of the open access divide, this study collects aggregated data from existi...

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

    Science.gov (United States)

    Pfister, Hans

    2014-01-01

    Physics students encountering electric circuits for the first time often ask why adding more resistors to a circuit sometimes increases and sometimes decreases the resulting total resistance. It appears that these students have an inadequate understanding of current flow and resistance. Students who do not adopt a model of current, voltage, and…

  4. A controllable resistor and its applications in pole-zero tracking frequency compensation methods for LDOs

    International Nuclear Information System (INIS)

    This paper presents a controllable resistor, which is formed by a MOS-resistor working in the deep triangle region and an auxiliary circuit. The auxiliary circuit can generate the gate-source voltage which is proportional to the output current of an low dropout regulator for the MOS-resistor. Thus, the equivalent output resistance of the MOS-resistor is inversely proportional to the output current, which is a suitable feature for pole-zero tracking frequency compensation methods. By switching the type of the MOS-resistor and current direction through the auxiliary circuit, the controllable resistor can be suitable for different applications. Three pole-zero tracking frequency compensation methods based on a single Miller capacitor with nulling resistor, unit-gain compensation cell and pseudo-ESR (equivalent serial resistor of load capacitor) power stage have been realized by this controllable resistor. Their advantages and limitations are discussed and verified by simulation results.

  5. The Open Access Divide

    Directory of Open Access Journals (Sweden)

    Jingfeng Xia

    2013-10-01

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

  6. Experimental study of Evanohm thin film resistors at subkelvin temperatures

    International Nuclear Information System (INIS)

    Thin film resistors, based on the Evanohm (Ni75%Cr20%Cu2.5%Al2.5%) alloy, have been investigated at cryogenic temperatures. The objective of the study is the development of the high value resistor for precision electrical measurements at low temperature and particularly for metrological triangle experiments. Thin film resistors of different configurations have been designed and fabricated by the thermal evaporation process. The resistivity of investigated resistors is 110 × 10?8 ? m; the resistance exhibits a Kondo minimum at a temperature near 30 K and increases with further reduction of temperature. In the temperature range 50–65 mK, the temperature coefficient reaches ?20 × 10?3 K?1. Power dependence measurements at subkelvin temperatures demonstrate that noticeable electron overheating takes place only at the power level above 10 pW for a 500 k? resistor. The electron–phonon coupling constant for the fabricated Evanohm thin films has been derived from experimental results

  7. Subnanosecond resistive high-voltage dividers for transient ground rise measurement in gas-insulated switchgear. Part II: Subnanosecond triple ladder

    Science.gov (United States)

    Melançon, C.; Mitchel, G. R.

    1987-05-01

    This paper describes a resistive voltage divider with subnanosecond rise time for use up to 50 kV using a ``triple ladder'' of metal film resistors. Its low-voltage attenuators incorporate fast switching diodes for oscilloscope protection. The divider is used to measure fast transients generated by breakdown in SF6.

  8. Resistor Loaded EBG Surfaces for Slot Antenna Design

    Directory of Open Access Journals (Sweden)

    Shenyi Cao

    2013-07-01

    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.

  9. A generalised formulation of the Laplacian approach to resistor networks

    International Nuclear Information System (INIS)

    An analytic approach is presented to developing exact expressions for the two-point resistance between arbitrary nodes on certain non-regular resistor networks. This generalises previous approaches, which only deliver results for networks of more regular geometry. The new approach exploits the second minor of the Laplacian matrix associated with the given network to obtain the resistance in terms of its eigenvalues and eigenvectors. The method is illustrated by application to the resistor network on the globe lattice, for which the resistance between two arbitrary nodes is obtained in the form of single summation. (paper)

  10. 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

  11. Design, construction, and testing of solution resistive divider applied in hundreds of kilovolts nanosecond pulse measurement.

    Science.gov (United States)

    Ge, Ya-Feng; Li, Lee; Liu, Yun-Long; Li, Mingjia; Kang, Qiang

    2014-10-01

    The solution resistive divider is often used considering its excellent high-frequency and withstanding voltage characteristics. This paper develops a nanosecond pulse measurement system based on the CuSO4 solution resistive divider, which can be used to measure high voltage impulses with rise time of 50 ns and amplitude of 300 kV. The low-voltage arm of the newly designed solution resistive divider is composed of noninductive metal film resistors. The newly designed resistive divider combines the advantages of the conventional solution resistive divider and metal film resistive divider. The stray parameters of the resistive divider are theoretically calculated and the circuit simulation is studied. Besides, the square wave response characteristics of the resistive divider are studied in the experiments. Considering the effect of frequency on the surge impedance of the cable, a matching cable of the same type with the transmission cable instead of a common matching resistor is used to improve the matching effects. In order to reduce the effects of electromagnetic interference on the measurement results, some shielding measures are taken. The experimental results show that the measurement system has good response characteristics in the practical application. PMID:25362455

  12. Monitoring the Digital Divide

    CERN Document Server

    Canessa, E; Matthews, W; Cottrell, R L A

    2003-01-01

    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 theresults from the ICTP sites and quantitatively identify regions with poor performance, identify trends, discuss experienc...

  13. Monitoring the Digital Divide

    OpenAIRE

    E Canessa; Cerdeira, H. A.; Matthews, W; Cottrell, R.L.

    2003-01-01

    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 sc...

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

    International Nuclear Information System (INIS)

    The KATRIN (KArlsruhe TRItium Neutrino) experiment aims to determine the mass of the electron antineutrino with a sensitivity of 200 meV by precisely measuring the electron spectrum of the tritium beta decay. This will be done by the use of a retarding spectrometer of the MAC-E-Filter type. To achieve the desired sensitivity the stability of the retarding potential of -18.6 kV has to be monitored with a precision of 3 ppm over at least two months. Since this is not feasible with commercial devices, two ppm-class high voltage dividers were developed, following the concept of the standard divider for DC voltages of up to 100 kV of the Physikalisch-Technische Bundesanstalt (PTB). In order to reach such high accuracies different effects have to be considered. The two most important ones are the temperature dependence of resistance and leakage currents, caused by insulators or corona discharges. For the second divider improvements were made concerning the high-precision resistors and the thermal design of the divider. The improved resistors are the result of a cooperation with the manufacturer. The design improvements, the investigation and the selection of the resistors, the built-in ripple probe and the calibrations at PTB will be reported here. The latter demonstrated a stability of about 0.1 ppm/month over a period of two years

  15. Melting the Divide

    Science.gov (United States)

    Gibson, S. M.

    2014-12-01

    Presenting Quaternary Environmental Change to students who fall into Widening Participation criteria at the University of Cambridge, gives a unique opportunity to present academic debate in an approachable and entertaining way. Literally by discussing the melting of our ice caps, melts the divide Cambridge has between its reputation and the reality for the brightest, underprivileged, students. There is a balance between presenting cutting edge research with the need to come across as accessible (and importantly valuable to "learning"). Climate change over the Quaternary lends itself well to this aim. By lecturing groups of potential students through the entire Quaternary in an hour, stopping to discuss how our ancestors interacted with past Interglacials and what are the mechanisms driving change (in generalized terms), you are able to introduce cutting edge research (such as the latest NEEM ice core) to the students. This shows the evolution and importance of higher education and academic research. The lecture leads well onto group discussions (termed "supervisions" in Cambridge), to explore their opinions on the concern for present Anthropogenic Climate Change in relation to Past Climate Change after being presented with images that our ancestors "made it". Here discussion thrives off students saying obvious things (or sarcastic comments!) which quickly can lead into a deep technical discussion on their terms. Such discussions give the students a zest for higher education, simply throwing Ruddiman's (2003) "The Anthroprocene Started Several Thousand Years Ago" at them, questions in a second their concept of Anthropogenic Climate Change. Supervisions lend themselves well to bright, articulate, students and by offering these experiences to students of Widening Participation criteria we quickly melt the divide between the reputation of Cambridge ( and higher education as a whole) and the day to day practice. Higher education is not for the privileged, but a free and open environment for the exchange of ideas. Quaternary Environmental Change lends itself, as an engaging and "fun" subject, well to potential students bridging the divide between ability and circumstance.

  16. 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)

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

    CERN Document Server

    Mrozik, Anna; Bilski, Pawel; Gieszczyk, Wojciech

    2014-01-01

    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...

  18. Logic delays of 5-?m resistor coupled Josephson logic

    International Nuclear Information System (INIS)

    Logic delays of resistor coupled Josephson logic (RCJL) have been investigated. An experimental circuit with a cascade chain of ten RCJL OR gates was fabricated using Pb-alloy Josephson IC technology with 5-?m minimum linewidth. Logic delay was measured to be as low as 10.8 ps with power dissipation of 11.7 ?W. This demonstrates a switching operation faster than those reported for other Josephson gate designs. Comparison with computer-simulation results is also presented

  19. Spin dependent trapping in a polycrystalline silicon integrated circuit resistor

    International Nuclear Information System (INIS)

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

  20. Regular Resistor Lattice Networks in Two Dimensions (Archimedean Lattices

    Directory of Open Access Journals (Sweden)

    M. Q. Owaidat

    2014-07-01

    Full Text Available In this paper, we investigate the two-vertex resistance on four Archimedean lattices. This technique is based on the Green's function corresponding to the Laplacian matrix of the lattice. The Laplacian matrix of the resistor network is determined by applying basic principles (Kirchhoff's and Ohm's laws in electrical circuit analysis, and Fourier transforms of the electric potential and current. We present some numerical results regarding the resistance between nearby lattice vertices.

  1. Embedded Resistors and Capacitors in Organic and Inorganic Substrates

    Science.gov (United States)

    Gerke, Robert David; Ator, Danielle

    2006-01-01

    Embedded resistors and capacitors were purchased from two technology; organic PWB and inorganic low temperature co-fire ceramic (LTCC). Small groups of each substrate were exposed to four environmental tests and several characterization tests to evaluate their performance and reliability. Even though all passive components maintained electrical performance throughout environmental testing, differences between the two technologies were observed. Environmental testing was taken beyond manufacturers' reported testing, but general not taken to failure. When possible, data was quantitatively compared to manufacturer's data.

  2. Why do bacteria divide?

    Science.gov (United States)

    Norris, Vic

    2015-01-01

    The problem of not only how but also why cells divide can be tackled using recent ideas. One idea from the origins of life - Life as independent of its constituents - is that a living entity like a cell is a particular pattern of connectivity between its constituents. This means that if the growing cell were just to get bigger the average connectivity between its constituents per unit mass - its cellular connectivity - would decrease and the cell would lose its identity. The solution is division which restores connectivity. The corollary is that the cell senses decreasing cellular connectivity and uses this information to trigger division. A second idea from phenotypic diversity - Life on the Scales of Equilibria - is that a bacterium must find strategies that allow it to both survive and grow. This means that it has learnt to reconcile the opposing constraints that these strategies impose. The solution is that the cell cycle generates daughter cells with different phenotypes based on sufficiently complex equilibrium (E) and non-equilibrium (NE) cellular compounds and structures appropriate for survival and growth, respectively, alias 'hyperstructures.' The corollary is that the cell senses both the quantity of E material and the intensity of use of NE material and then uses this information to trigger the cell cycle. A third idea from artificial intelligence - Competitive Coherence - is that a cell selects the active subset of elements that actively determine its phenotype from a much larger set of available elements. This means that the selection of an active subset of a specific size and composition must be done so as to generate both a coherent cell state, in which the cell's contents work together harmoniously, and a coherent sequence of cell states, each coherent with respect to itself and to an unpredictable environment. The solution is the use of a range of mechanisms ranging from hyperstructure dynamics to the cell cycle itself. PMID:25932025

  3. Why do bacteria divide?

    Science.gov (United States)

    Norris, Vic

    2015-01-01

    The problem of not only how but also why cells divide can be tackled using recent ideas. One idea from the origins of life – Life as independent of its constituents – is that a living entity like a cell is a particular pattern of connectivity between its constituents. This means that if the growing cell were just to get bigger the average connectivity between its constituents per unit mass – its cellular connectivity – would decrease and the cell would lose its identity. The solution is division which restores connectivity. The corollary is that the cell senses decreasing cellular connectivity and uses this information to trigger division. A second idea from phenotypic diversity – Life on the Scales of Equilibria – is that a bacterium must find strategies that allow it to both survive and grow. This means that it has learnt to reconcile the opposing constraints that these strategies impose. The solution is that the cell cycle generates daughter cells with different phenotypes based on sufficiently complex equilibrium (E) and non-equilibrium (NE) cellular compounds and structures appropriate for survival and growth, respectively, alias ‘hyperstructures.’ The corollary is that the cell senses both the quantity of E material and the intensity of use of NE material and then uses this information to trigger the cell cycle. A third idea from artificial intelligence – Competitive Coherence – is that a cell selects the active subset of elements that actively determine its phenotype from a much larger set of available elements. This means that the selection of an active subset of a specific size and composition must be done so as to generate both a coherent cell state, in which the cell’s contents work together harmoniously, and a coherent sequence of cell states, each coherent with respect to itself and to an unpredictable environment. The solution is the use of a range of mechanisms ranging from hyperstructure dynamics to the cell cycle itself. PMID:25932025

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

    OpenAIRE

    Mrozik, Anna; Marczewska, Barbara; Bilski, Pawel; Gieszczyk, Wojciech

    2014-01-01

    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, commerci...

  5. 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.

  6. Testing method for measuring corrosion resistance of surface mount chip resistors

    OpenAIRE

    Reid, M; Collins, Maurice N; Dalton, Eric D; Punch, Jeff; Tanner, D.A

    2012-01-01

    Surface mount chip resistors are amongst the simplest and most inexpensive of all components used in electronic circuits and systems. Typically, resistor failure modes include open circuits, resistive shorts or variations in resistance indicating parametric drift or intermittent failure, which in some applications result in overall system failure. Corrosion is currently believed to be the number one failure mechanism for chip resistors deployed in developing markets such as Centra...

  7. 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)

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

    Science.gov (United States)

    Werner, Thomas R. (Argonne, IL); Falco, Charles M. (Tucson, AZ); Schuller, Ivan K. (Woodridge, IL)

    1984-01-01

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

  9. Measurements of fuse and resistor characteristics for multimegajoule 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-?s) conditions to determine their ability to protect capacitor bank components during faults. Currents in the resistors ranged from 20 to 40 kA per resistor. The experimental results for the fuses have been compared to the manufacturer's data for minimum melt and maximum let-through action integrals and to exploding bridge wire computer models

  10. Electrical Switching of Perovskite Thin-Film Resistors

    Science.gov (United States)

    Liu, Shangqing; Wu, Juan; Ignatiev, Alex

    2010-01-01

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

  11. 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.

  12. 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

  13. Resistors Network Model of Bcc Cell for Investigating Thermal Conductivity of Nanofluids

    Science.gov (United States)

    Masturi, Masturi; Sustini, Euis; Khairurrijal, Khairurrijal; Abdullah, Mikrajuddin

    2011-12-01

    A model was developed to investigate thermal conductivity of nanofluids. It was based on resistors circuit network in bcc cell as alternative form of simple cubic cell has been successfully developed. The present model has involved the Brownian motion of nanoparticles in the fluid with an assumption that the nanoparticles are in low volume fraction so the diameter size of nanoparticle can be neglected in comparison to particles distance. Generally, this model was very fit to experimental results has been obtained from some authors. As an example, for alumina-water nanofluid, that is alumina (Al2O3) dispersed in water, it was found that the enhancement of its thermal conductivity calculated using this model was in good agreement with experimental results that it tended to increase as nanoparticle fraction increases. As in alumina-water, the agreement was also shown in titania (TiO2)-water and cuprum oxide (CuO)-water. This model also showed the dependence of thermal conductivity enhancement to diameter size of nanoparticle and temperature of the nanofluid. In relation to diameter size, thermal conductivity enhancement decreases as diameter size increases. Otherwise, thermal conductivity enhancement increases as temperature increases. However, even though this model was very close to experimental results, the problem of this model was in dimensionless constant that varied for different nanofluids.

  14. Sociology: The growing climate divide

    Science.gov (United States)

    Hoffman, Andrew J.

    2011-07-01

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

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

    International Nuclear Information System (INIS)

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

  16. 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)

  17. Applications of the superconducting lossless resistor in electric power systems

    Energy Technology Data Exchange (ETDEWEB)

    Qian Ping; Chen Jiyan; Hua Rong; Chen Zhongming

    2003-04-15

    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)

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

    Directory of Open Access Journals (Sweden)

    Taufiqqurrachman

    2014-03-01

    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.

  19. Recursion-transform method for computing resistance of the complex resistor network with three arbitrary boundaries

    Science.gov (United States)

    Tan, Zhi-Zhong

    2015-05-01

    We develop a general recursion-transform (R-T) method for a two-dimensional resistor network with a zero resistor boundary. As applications of the R-T method, we consider a significant example to illuminate the usefulness for calculating resistance of a rectangular m ×n resistor network with a null resistor and three arbitrary boundaries, a problem never solved before, since Green's function techniques and Laplacian matrix approaches are invalid in this case. Looking for the exact calculation of the resistance of a binary resistor network is important but difficult in the case of an arbitrary boundary since the boundary is like a wall or trap which affects the behavior of finite network. In this paper we obtain several general formulas of resistance between any two nodes in a nonregular m ×n resistor network in both finite and infinite cases. In particular, 12 special cases are given by reducing one of the general formulas to understand its applications and meanings, and an integral identity is found when we compare the equivalent resistance of two different structures of the same problem in a resistor network.

  20. Influences of additives on the electrical properties of lead-free thick film resistors

    International Nuclear Information System (INIS)

    Lead-free thick film resistors were prepared by mixing of ruthenium oxide (RuO2) and K2O-CaO-B2O3-SiO2 glass. Sheet resistivities of the thick film resistors prepared with different RuO2/glass ratios in this study were in the range between 0.2 and 100 k?/sq. When RuO2/glass volume ration equaled to 15/85, the sheet resistivity of the resistor was about 1.52 k?/sq. It had temperature coefficient of resistance (TCR) value of 523 ppm/oC. Five metal oxides, such as Nb2O5, MnO2, MoO3, TiO2 and Fe2O3 were used as TCR adjustment agents. Resistivities of the resistor films increased with increasing Nb2O5 contents. The resistivities, however, decreased with increasing Fe2O3 and MnO2 contents. For 15 vol% RuO2 thick film resistor, the TCR value of the resistor became negative, when 4 wt% NB2O3 or MnO2 was added to the glass flint. Additive of MoO3 did not have much influence on the resistivity and TCR value. Both resistivity and TCR value of the resistor decreased with increasing Fe2O3 content. (author)

  1. Picture Board: Divide and Color

    Science.gov (United States)

    TERC

    2010-01-01

    Divide a bulletin board or poster board so everyone has the same area to decorate. Add some math by asking the group to figure out equal sections. Brainstorm layouts: how many ways can we come up with to divide the poster board so everyone gets the same shape piece—or for more challenge, so that everyone gets the same area piece? Together, choose one of the layouts, then measure, plan, and design. This activity brings in lots of areas of math: multiplication, division, measurement, area, and fractions. Available as a web page or downloadable pdf.

  2. Characteristics of burden resistors for high-precision DC current transducers

    CERN Document Server

    Fernqvist, G; Hudson, G; Pickering, J

    2007-01-01

    The DC current transducer (DCCT) and accompanying A/D converter determine the precision of a power converter in accelerator operation. In the LHC context this precision approaches 10-6 (1 ppm). Inside the DCCT a burden resistor is used to convert the current to an output voltage. The performance of this resistor is crucial for the accuracy, temperature behaviour, settling time and longterm drift of the DCCT. This paper reports on evaluations, a new parameter called â??power coefficientâ? (PC) and test results from some different types of resistors available on the market.

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

    International Nuclear Information System (INIS)

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

  4. The research of non-uniformity correction technologies for resistor array dynamic infrared scene projector

    Science.gov (United States)

    Zhao, Hong-ming; Fei, Jin-dong; Yu, Hong; Du, Hui-jie; Zhang, Yi

    2011-08-01

    The resistor array devices are commonly used to produce dynamic two dimensional infrared images in the infrared scene projectors. A non-uniformity caused by many factors is the main source of image fixed pattern noise of the projectors based on resistor array devices. A prior non-uniformity correction procedure must be done before the dynamic infrared image generation for the hardware-in-the-loop simulation test and evaluation. In this paper, the developments and details of the non-uniformity correction technologies for resistor array dynamic infrared scene projector are investigated. The research is commenced directed towards understanding the cause of spatially-distributed radiance non-uniformities of resistor array device, and the fundamental elements that underlie the non-uniformity correction technologies in dynamic infrared scene projection system.

  5. Interdependent resistor networks with process-based dependency

    Science.gov (United States)

    Danziger, Michael M.; Bashan, Amir; Havlin, Shlomo

    2015-04-01

    Studies of resilience of interdependent networks have focused on structural dependencies between pairs of nodes across networks but have not included the effects of dynamic processes taking place on the networks. Here we study the effect of dynamic process-based dependencies on a system of interdependent resistor networks. We describe a new class of dependency in which a node’s functionality is determined by whether or not it is actually carrying current and not just by its structural connectivity to a spanning component. This criterion determines its functionality within its own network as well as its ability to provide support-but not electrical current-to nodes in another network. We present the effects of this new type of dependency on the critical properties of ? and {{B}? }, the overall conductivity of the system and the fraction of nodes which carry current, respectively. Because the conductance of current has direct physical effects (e.g. heat, magnetic induction), the development of a theory of process-based dependency can lead to innovative technology. As an example, we describe how the theory presented here could be used to develop a new kind of highly sensitive thermal or gas sensor.

  6. Percolation approach to discharge phenomenon in nonlinear resistor network

    Science.gov (United States)

    Matsumoto, Shogo; Odagaki, Takashi

    2014-03-01

    In order to understand the discharge process such as the lightning and streamer discharge, we focus on the percolation of ionized regions which are produced by the local electric field and remote ionization. Exploiting a two dimensional nonlinear resistor network in a square lattice, we investigate discharge when two opposite sides of the lattice are subjected to a constant voltage difference. Each site is assumed to be ionized randomly with probability in proportion to the strength of the electric field, and the resistivity between ionized sites is assumed to be million times smaller than the original resistivity. Using Monte Carlo simulation, we obtain the current and the distribution of clusters of ionized sites as functions of the fraction of ionized sites. The current begins to rise up at a critical point, signifying the transition of non-conductive to conductive state. We find that the critical point for the current is much smaller than the critical percolation probability of the standard site percolation. We also report that singular behavior of the cluster distribution is expected at a critical fraction different from that for the current, and discuss the scaling relation among critical exponents obtained from the current and the cluster distribution.

  7. Information Societies and Digital Divides

    CERN Document Server

    Sorj, Bernardo

    2008-01-01

    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 ...

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

    Science.gov (United States)

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

    2001-01-01

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

  9. Development of beam-based alignment system using a switchable shunt resistor for HLS

    International Nuclear Information System (INIS)

    The development of beam-based alignment system for Hefei Light Source (HLS) is presented. In this system, a switchable shunt resistor was installed on quadrupole to bypass a small percentage of the magnet current, and solid-state relays were used to switch the shunt resistor. The system can be used to measure the offset of the beam position monitor (BPM) with respect to the magnetic center of a quadrupole. Some measurement results for HLS are given

  10. What is Ohmic? I-V Characteristics of a Diode vs. a Resistor

    Science.gov (United States)

    The Materials Science and Technology Teacher's Workshop (MAST) provides this activity as a vehicle to examine the I-V characteristics of a diode versus a resistor. The exercise will measure the voltage drop across both a diode and a resistor as voltage is varied. The students will then discover the relationship between current and voltage.The lesson includes step by step directions for the experiment.The activity should require about 40-50 minutes of class time to complete.

  11. Resistance and Resistance Fluctuations in Random Resistor Networks Under Biased Percolation

    OpenAIRE

    Pennetta, C.; Reggiani, L.; Trefa?n, Gy; Alfinito, E.

    2002-01-01

    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 f...

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

    OpenAIRE

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

    2009-01-01

    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...

  13. Implementation of an analogue model of a memristor based on a light-dependent resistor

    International Nuclear Information System (INIS)

    In this paper, an analogue model of a memristor using a light-dependent resistor (LDR) is presented. This model can be simplified into two parts: a control circuit and a variable resistor. It can be used to easily verify theoretical presumptions about the switching properties of memristors. This LDR-based memristor model can also be used in both simulations and experiments for future research into memristor applications. The paper includes mathematical models, simulations, and experimental results

  14. Electoral Systems in Divided Societies

    OpenAIRE

    Lal, Brij V.; Larmour, Peter

    2012-01-01

    Elections can increase tension in ethnically divided societies, like Fiji. The way constituencies are drawn and votes counted can also affect the result. First-past-the post can deliver lopsided results, while proportional representation may give excessive influence to small, fringe parties. Fiji’s Constitution Review Commission believed a system of alternative voting in ethnically mixed constituencies would encourage politicians, and parties, to take into account the interests of other eth...

  15. 40 CFR 1065.248 - Gas divider.

    Science.gov (United States)

    2010-07-01

    ...POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Flow-Related Measurements § 1065.248 Gas divider...during testing. You may use critical-flow gas dividers, capillary-tube gas dividers, or thermal-mass-meter gas...

  16. TryEngineering: Using Ohm’s Law to Build a Voltage Divider

    Science.gov (United States)

    2012-07-30

    In this high school lab, students design and build one of the basic circuits of electrical engineering: the voltage divider -- a form of linear circuit capable of producing a wide range of output voltages. The lesson provides scaffolding as students explore the mathematical relationships of parallel and series resistors as they build light emitting diodes. The driving question of the lesson: How do electrical engineers apply Ohm's law in the design of electrical circuits? This lesson provides educators with comprehensive supplemental material, including step-by-step breadboard instructions and matrices of possible voltage outputs. For additional student practice, see Related Materials to download an editor-recommended worksheet on voltage divider electronics (37 problems with answers provided). This resource is part of a collection maintained by the Institute of Electrical and Electronics Engineers (IEEE).

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

    Science.gov (United States)

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

    1982-08-31

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

  18. 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

  19. 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)

  20. Split-cross-bridge resistor for testing for proper fabrication of integrated circuits

    Science.gov (United States)

    Buehler, M. G. (inventor)

    1985-01-01

    An electrical testing structure and method is described whereby a test structure is fabricated on a large scale integrated circuit wafer along with the circuit components and has a van der Pauw cross resistor in conjunction with a bridge resistor and a split bridge resistor, the latter having two channels each a line width wide, corresponding to the line width of the wafer circuit components, and with the two channels separated by a space equal to the line spacing of the wafer circuit components. The testing structure has associated voltage and current contact pads arranged in a two by four array for conveniently passing currents through the test structure and measuring voltages at appropriate points to calculate the sheet resistance, line width, line spacing, and line pitch of the circuit components on the wafer electrically.

  1. Study of steatites for using as a high density resistor nucleus; Estudo de esteatito para utilizacao como nucleo de resistor de alta densidade

    Energy Technology Data Exchange (ETDEWEB)

    Salas, Humberto Terrazas; Costa, Antonio Carlos Lopes da; Barbosa, Joao Batista Santos; Silva, Luiz Carlos da; Rocha, Francisco de Assis [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil)]. E-mail: salasht@cdtn.br

    2005-07-01

    In nuclear facilities where high density power resistors are applied in fuel irradiation circuits in the PWR reactor type, the probability of accident is high, therefore, it is necessary to experimentally test the nuclear facility safety project. In order to reach this goal, it is necessary to use an electric isolated material capable of withstanding high temperatures without melting or becoming deteriorated. That is where the lytologic type, classified as steatite or soapstone, must be used. The present work characterizes the steatite samples, suggesting the lytologic type to be used as the high density power resistors nucleus. Samples were selected from a steatite' processing industry located in the district of Cachoeira do Campo in Minas Gerais State. These lytologic types were sawed, evaluated macroscopically, subjected to specific preparation methods for chemical analysis and X rays diffraction, exposed to high temperatures, as well as petrographic studies and microanalyses. Samples marked by lower concentration levels of carbonates. (author)

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

    Science.gov (United States)

    Raymond, Leonard S. (Tucson, AZ)

    1983-01-01

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

  3. Break-collapse method for resistor networks-renormalization group applications

    International Nuclear Information System (INIS)

    The break-collapse method recently introduced for the q-state Potts model is adapted for resistor networks. This method greatly simplifies the calculation of the conductance of an arbitrary two-terminal d-dimensional array of conductances, obviating the use of either Kirchhoff's laws or the star-triangle or similiar transformations. Related properties are discussed as well. An illustrative real-space renormalization-group treatment of the random resistor problem on the square lattice is presented; satisfactory results are obtained. (Author)

  4. Crossroads - Bridging the Digital Divide

    Directory of Open Access Journals (Sweden)

    David Cobb

    2005-03-01

    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.

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

    International Nuclear Information System (INIS)

    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 RuO2 powders (fine-grained and coarse-grained RuO2). 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  7. Comparing Internet and Mobile Phone Digital Divides.

    Science.gov (United States)

    Rice, Ronald E.; Katz, James E.

    2002-01-01

    Discussion of the digital divide focuses on the Internet and mobile phone digital divide. Analyses of a telephone survey from 2000 considers similarities and differences in three kinds of digital dividers for both the Internet and the mobile phone: users and nonusers, users and dropouts, and recent and veteran users. (Author/LRW)

  8. Low-powered transistor divider for PMT

    International Nuclear Information System (INIS)

    A transistor high-voltage divider for photomultipliers is developed. The circuit contains a high-resistance linear resistive divider for setting potential distribution between dynodes and emitter followers to support this distribution. The divider is characterized by a low level of diffused power and stability of photomultiplier gain at change of average anode current in the whole range of measurements

  9. Manufacturing of precision resistors based on Ni-P and Ni-W-P layers obtained by means of chemical reduction method

    International Nuclear Information System (INIS)

    The paper describes a new method of obtaining of Ni-W-P resistor layers, featuring elevated electrical stability. Such layers may be introduced into the manufacturing process of precise metal film resistor. (author)

  10. Chaos, brain and divided consciousness.

    Science.gov (United States)

    Bob, Petr

    2007-01-01

    Modern trends in psychology and cognitive neuroscience suggest that applications of nonlinear dynamics, chaos and self-organization seem to be particularly important for research of some fundamental problems regarding mind-brain relationship. Relevant problems among others are formations of memories during alterations of mental states and nature of a barrier that divides mental states, and leads to the process called dissociation. This process is related to a formation of groups of neurons which often synchronize their firing patterns in a unique spatial maner. Central theme of this study is the relationship between level of moving and oscilating mental processes and their neurophysiological substrate. This opens a question about principles of organization of conscious experiences and how these experiences arise in the brain. Chaotic self-organization provides a unique theoretical and experimental tool for deeper understanding of dissociative phenomena and enables to study how dissociative phenomena can be linked to epileptiform discharges which are related to various forms of psychological and somatic manifestations. Organizing principles that constitute human consciousness and other mental phenomena from this point of view may be described by analysis and reconstruction of underlying dynamics of psychological or psychophysiological measures. These nonlinear methods in this study were used for analysis of characteristic changes in EEG and bilateral electrodermal activity (EDA) during reliving of dissociated traumatic and stressful memories and during psychopathological states. Analysis confirms a possible role of chaotic transitions in the processing of dissociated memory. Supportive finding for a possible chaotic process related to dissociation found in this study represent also significant relationship of dissociation, epileptiform discharges measured by typical psychopathological manifestations and characteristic laterality changes in bilateral EDA in patients with schizophrenia and depression. Increased level of psychopathological symptoms indicates close relationship to the right-left EDA asymmetry and asymmetry of information entropy calculated by non-linear recurrence quantification analysis of EDA records. Because epileptiform activity has specific chaotic behaviour and calculated information entropy from EDA records reflects the complexity of the deterministic structure in the system there is a relevant assumption that unilaterally increased complexity may produce interhemispheric disbalance and increased chaoticity which hypothetically may serve as a dynamic source of epileptiform discharges related to trauma induced kindling mechanism. Specific form of chaotic inner organization which cannot be explained only as a consequence of external causality support also psychophysiological data that lead to the so-called self-organizing theory of dreaming by Kahn and Hobson. This study suggests that self-organizing theory of dreaming is particularly important with respect to problem of memory formation and processing during dissociative states characteristic for dreams. Recent data and also findings of this study support the research utility of chaos theory in psychology and neuroscience, and also its conceptual view of dynamic ordering factors and self-organization underlying psychological processes and brain physiology. PMID:17867519

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

    Energy Technology Data Exchange (ETDEWEB)

    Vinayak, Seema [Solid State Physics Laboratory, Lucknow Road, Delhi-110054 (India)]. E-mail: seema_vinayak@rediffmail.com; Vyas, H.P. [Solid State Physics Laboratory, Lucknow Road, Delhi-110054 (India); Muraleedharan, K. [Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad-500058 (India); Vankar, V.D. [Indian Institute of Technology Delhi, Hauz Khas, New Delhi- 110016 (India)

    2006-08-30

    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 {sub 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 {sub 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.

  12. 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

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

    Science.gov (United States)

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

    2008-01-01

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

  14. 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

  15. Heat capacity of thick-film resistor thermometers and pure RuO 2 at low temperatures

    Science.gov (United States)

    Volokitin, Ya. E.; Thiel, R. C.; de Jongh, L. J.

    The heat capacity of commercial thick-film chip resistors has been measured in the temperature range 0.1-2K. Three different types of resistors used as low temperature thermometers were investigated. The heat capacity of all samples shows a Schottky-type anomaly with the maximum at 0.4K amounting to 1?J K -1 for the largest unit. We also report the data on the specific heat of a thermometer component, RuO 2, and show that it has no anomalous behaviour. The peak in heat capacity of these resistors puts limitations on using them as thermometers for low temperature calorimeters.

  16. 1/f Electrical Noise in Planar Resistors: The Joint Effect of a Backgating Noise and an Instrumental Disturbance

    OpenAIRE

    Izpura Torres, Jose? Ignacio

    2008-01-01

    Any planar resistor (channel) close to a conducting layer left floating (gate) forms a capacitor C whose thermal voltage noise (kT/C noise) has a backgating effect on the sheet resistance of the channel that is a powerful source of 1/f resistance noise in planar resistors and, hence, in planar devices. This 1/f spectrum is created by the bias voltage V DS applied to the resistor, which is a disturbance that takes it out of thermal equilibrium and changes the resistance noise that existed in t...

  17. Parochial Geographies: Growing up in Divided Belfast

    Science.gov (United States)

    Leonard, Madeleine

    2010-01-01

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

  18. 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

  19. Study of steatites for using as a high density resistor nucleus

    International Nuclear Information System (INIS)

    In nuclear facilities where high density power resistors are applied in fuel irradiation circuits in the PWR reactor type, the probability of accident is high, therefore, it is necessary to experimentally test the nuclear facility safety project. In order to reach this goal, it is necessary to use an electric isolated material capable of withstanding high temperatures without melting or becoming deteriorated. That is where the lytologic type, classified as steatite or soapstone, must be used. The present work characterizes the steatite samples, suggesting the lytologic type to be used as the high density power resistors nucleus. Samples were selected from a steatite' processing industry located in the district of Cachoeira do Campo in Minas Gerais State. These lytologic types were sawed, evaluated macroscopically, subjected to specific preparation methods for chemical analysis and X rays diffraction, exposed to high temperatures, as well as petrographic studies and microanalyses. Samples marked by lower concentration levels of carbonates. (author)

  20. Nanoporous carbon tunable resistor/transistor and methods of production thereof

    Science.gov (United States)

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

    2014-04-22

    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.

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

    OpenAIRE

    Sujitha, S.; Venkatesh, Dr C.

    2014-01-01

    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.

  2. Percolation-induced exponential scaling in the large current tails of random resistor networks

    OpenAIRE

    Shi, Feng; Wang, Simi; Mucha, Peter J.; Forest, M. Gregory

    2012-01-01

    There is a renewed surge in percolation-induced transport properties of diverse nano-particle composites (cf. RSC Nanoscience & Nanotechnology Series, Paul O'Brien Editor-in-Chief). We note in particular a broad interest in nano-composites exhibiting sharp electrical property gains at and above percolation threshold, which motivated us to revisit the classical setting of percolation in random resistor networks but from a multiscale perspective. For each realization of random...

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

    OpenAIRE

    Soliman, Ahmed M.

    2010-01-01

    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 oth...

  4. High-strain response of piezoresistive thick-film resistors on titanium alloy substrates

    OpenAIRE

    Jacq, Caroline; Maeder, Thomas; Ryser, Peter

    2004-01-01

    We examine, in this work, the integration and high-strain response of piezoresistive thick-film resistors on titanium and titanium alloy, as compared with ferritic stainless steel and the standard alumina substrates. In general, titanium and its alloys are relatively ill suited for use as a thick-film substrate using the standard 850 °C firing process, because of its low oxidation resistance and tendency to dissolve oxygen. This problem can be alleviated by applying suitable thick-fil...

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

    Directory of Open Access Journals (Sweden)

    S.Sujitha

    2014-07-01

    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.

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

    OpenAIRE

    Gulmurza Abdurakhmanov

    2011-01-01

    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 firi...

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

    OpenAIRE

    Engheta, Nader; Salandrino, Alessandro; Alu, Andrea

    2004-01-01

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

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

    Directory of Open Access Journals (Sweden)

    V. Niranjan

    2014-09-01

    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.

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

    Science.gov (United States)

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

    2005-05-01

    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.

  10. 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.

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

    International Nuclear Information System (INIS)

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

  12. Pyramidal resistor networks for electrical impedance tomography with partial boundary measurements

    International Nuclear Information System (INIS)

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

  13. A “Divide-by-Odd Number” Injection-Locked Frequency Divider.

    OpenAIRE

    Asghar, Malik Summair

    2013-01-01

    The use of resonant CMOS frequency dividers with direct injection in frequencysynthesizers has increased in recent years due to their lower power consumptioncompared to conventional digital prescalers. The theoretical and experimentalaspects of these dividers have received great attention. This masters thesis workis a continuation of earlier work, based on the fundamentals of Injection-LockedFrequency Dividers (ILFD’s). The LC CMOS ILFD with direct injection is wellknownfor its divide-by-2 ...

  14. Middlebrow Modernism: Britten's Operas and the Great Divide

    OpenAIRE

    Chowrimootoo, Christopher Craig

    2013-01-01

    This study examines the way Britten's operas and their audiences muddied the waters of the so-called "great divide" between modernism and mass culture, mediating between the aesthetics of difficulty and distinction on the one hand, and the pleasures and conventions associated with popular opera on the other. Using the fraught responses of early critics as a way in, I examine the precise musical and critical strategies through which the operas confounded a range of marked modernist binaries - ...

  15. CMOS Current-Mode Companding Divider

    Science.gov (United States)

    Lin, Kuo-Jen

    A CMOS current-mode companding divider is presented. Currents of both dividend and divisor are compressed into log-domain. Then the logarithm current of divisor is subtracted from the logarithm current of dividend. After expanding the subtraction result, the division function could be achieved. The simulation results indicate that the proposed divider has with good performance at only 1.8V supply voltage.

  16. Performance predictability of divide and conquer skeletons

    OpenAIRE

    Saez, Fernando; Printista, Alicia Marcela

    2008-01-01

    Parallel divide and conquer computations, encompassing a wide variety of applications, can be modeled and encapsulated as a high level primitive called skeleton. The paper deals with a skeleton designed for parallel divide and conquer algorithms that provide hypercubical communications among processes The paper also introduces an accurate timing model designed for prediction of proposed primitive. The timing analysis model presented here still characterizing the communication time through ...

  17. 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)

  18. Water hammer

    International Nuclear Information System (INIS)

    The overall NRC program for the resolution of the water hammer issue is divided into four tasks: water hammer summary reports; revision of CP and OL review procedures; water hammer positions for operating reactors; and water hammer safety studies

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

    Science.gov (United States)

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

    2008-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Nonofo C. Sedimo

    2011-03-01

    Full Text Available Background: Botswana is putting in place initiatives towards establishing itself as a knowledgebased economy. Transformation from a resource-based to a knowledge-based economy is partly hinged on innovation, research and development capability, knowledge channels, and the funding of research and development activities.Objectives: Bridging the digital divide and narrowing the intra-national divide brings about global information and communication technology (ICT usage that translates into changing work patterns and eventually transformed economies. This article outlines the different interventions implemented in Botswana to bridge the divide. The South Korean experience in bridging the divide is discussed so as to serve as lessons on how to effectively bridge the divide to Botswana’s initiatives.Method: Using a mix of exploratory and empirical study, this article presents the findings on the status of ICT uptake in Botswana and investigates the level of the digital divide in the country.Results: The results of the study show that the digital divide is much more evident in Botswana than in South Korea. South Korea has put in place robust strategic initiatives towards reducing the digital divide and this has largely transcended into its transformation into a full-fledged knowledge society.Conclusion: This article is timely as it unearths the different pointers that may be utilised in policy formation and what interventions need to be taken at both the individual and national level to bridge the digital divide.

  1. Zero-point energy in the Johnson noise of resistors: Is it there?

    CERN Document Server

    Kish, Laszlo B

    2015-01-01

    There is a longstanding debate about the zero-point term in the Johnson noise voltage of a resistor: Is it indeed there or is it only an experimental artifact due to the uncertainty principle for phase-sensitive amplifiers? We show that, when the zero-point term is measured by the mean energy and force in a shunting capacitor and, if these measurements confirm its existence, two types of perpetual motion machines could be constructed. Therefore an exact quantum theory of the Johnson noise must include also the measurement system used to evaluate the observed quantities. The results have implications also for phenomena in advanced nanotechnology.

  2. Generalized Kirchhoff-Law-Johnson-Noise (KLJN) secure key exchange system using arbitrary resistors

    CERN Document Server

    Vadai, Gergely; Gingl, Zoltan

    2015-01-01

    The Kirchhoff-Law-Johnson-Noise (KLJN) secure key exchange system has been introduced as a simple, very low cost and efficient classical physical alternative to quantum key distribution systems. The ideal system uses only a few electronic components - identical resistor pairs, switches and interconnecting wires - to guarantee perfectly protected data transmission. We show that a generalized KLJN system can provide unconditional security even if it is used with significantly less limitations. The more universal conditions ease practical realizations considerably and support more robust protection against attacks. Our theoretical results are confirmed by numerical simulations.

  3. Zero-point energy in the Johnson noise of resistors: Is it there?

    OpenAIRE

    Laszlo B. Kish

    2015-01-01

    There is a longstanding debate about the zero-point term in the Johnson noise voltage of a resistor: Is it indeed there or is it only an experimental artifact due to the uncertainty principle for phase-sensitive amplifiers? We show that, when the zero-point term is measured by the mean energy and force in a shunting capacitor and, if these measurements confirm its existence, two types of perpetual motion machines could be constructed. Therefore an exact quantum theory of the...

  4. Sizing of the Series Dynamic Breaking Resistor in a Doubly Fed Induction Generator Wind Turbine

    DEFF Research Database (Denmark)

    Soliman, Hammam; Wang, Huai

    2014-01-01

    This paper investigates the effect of Series Dynamic Breaking Resistor (SDBR) sizing on a Doubly Fed Induction Generator (DFIG) based wind power conversion system. The boundary of the SDBR value is firstly derived by taking into account the controllability of the rotor side converter and the maximum allowable voltage of the stator. Then the impact of the SDBR value on the rotor current, stator voltage, DC-link voltage, reactive power capability and introduced power loss during voltage sag operation is evaluated by simulation. The presented study enables a trade-off sizing of the SDBR among the above performance factors.

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

    Directory of Open Access Journals (Sweden)

    Ahmed M Soliman

    2010-09-01

    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.

  6. Congenital divided naevus of the eyelids.

    OpenAIRE

    Mcdonnell, P. J.; Mayou, B. J.

    1988-01-01

    A newborn infant presenting with a divided congenital melanocytic naevus of the eyelid is described. Because of the severe disfigurement, risk of later malignant change in the lesion, and the possibility of deprivation amblyopia, early surgical treatment is recommended for all medium and large congenital melanocytic naevi of the eyelid. Surgery in the first few months of life gives the best cosmetic results.

  7. Bridging the digital divide with mobile services

    CERN Document Server

    Yelton, Andromeda

    2013-01-01

    In this issue of Library Technology Reports, Andromeda Yelton shows how libraries can build on the breadth of this population to help bridge the digital divide and provide even greater access to information. Yelton breaks down the demographics of mobile internet users, provides examples of how different libraries are reaching out to these populations, and suggests what the future may hold for this trend.

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

    International Nuclear Information System (INIS)

    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.

  9. Experimental verification of temperature coefficients of resistance for uniformly doped P-type resistors in SOI

    International Nuclear Information System (INIS)

    Many today's microsystems like strain-gauge-based piezoresistive pressure sensors contain doped resistors. If one wants to predict correctly the temperature impact on the performance of such devices, the accurate data about the temperature coefficients of resistance (TCR) are essential. Although such data may be calculated using one of the existing mobility models, our experiments showed that we can observe the huge mismatch between the calculated and measured values. Thus, in order to investigate the TCR values, a set of the test structures that contained doped P-type resistors was fabricated. As the TCR value also depends on the doping profile shape, we decided to use the very thin, 340 nm thick SOI wafers in order to fabricate the quasi-uniformly doped silicon layers ranging from 2 × 1017 at cm?3 to 1.6 × 1019 at cm?3. The results showed that the experimental data for the first-order TCR are quite far from the calculated ones especially over the doping range of 1018–1019 at cm?3 and quite close to the experimental ones obtained by Bullis about 50 years ago for bulk silicon. Moreover, for the first time, second-order coefficients that were not very consistent with the calculations were obtained.

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

    Science.gov (United States)

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

    2012-04-01

    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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    Bearman, Gonzalo; Stevens, Michael P

    2014-01-01

    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

  13. Analyzing Broadband Divide in the Farming Sector

    DEFF Research Database (Denmark)

    Jensen, Michael; Gutierrez Lopez, Jose Manuel

    2013-01-01

    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.

  14. Bridging the Divide between Science and Journalism

    OpenAIRE

    Marincola Francesco M; Van Eperen Laura; Strohm Jennifer

    2010-01-01

    Abstract There are countless reasons nearly every scientist should learn how to communicate effectively with the media, including increased understanding of critical research findings to attract or sustain funding and build new professional partnerships that will further propel forward research. But where do scientists begin? Bridging the Divide between Science and Journalism offers practical tips for any scientist looking to work with the media. Given the traditional and internet-based sourc...

  15. Self-organization of divided hierarchy

    Science.gov (United States)

    Odagaki, Takashi; Kitada, Keigo; Omizo, Kenta; Fujie, Ryo

    2015-03-01

    There are two types of extreme form of hierarchy, one is the plutonomy where small fraction of winners and losers and many people in the middle class appear and the other a divided hierarchy where half of population become winners and the remaining half become losers. We study the emergence of the divided hierarchy in a model society which consists of bellicose individuals who always try to fight and fight with the strongest neighbor and pacific individuals who always try not to fight and when necessary fight with the weakest neighbor. In our model society, (1) individuals make random walk on a square lattice, (2) when two individuals encounter they fight each other and (3) the winner deprives wealth from the loser. By a Monte Carlo simulation, we show that there are two transitions when the population density is increased; one is a transition from the egalitarian society to a hierarchical society I where winners, losers and middle classes coexist and the other is a transition from the hierarchical society I to a hierarchical society II where winners and losers exist but no middle classes exist, that is the divided hierarchy. We also show that clusters consisting mostly of bellicose individuals appear in the hierarchical society I.

  16. REGENERATIVE GAS TURBINES WITH DIVIDED EXPANSION

    DEFF Research Database (Denmark)

    Elmegaard, Brian; Qvale, Einar BjØrn

    2004-01-01

    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.

  17. Media Literacy in Times of Media Divides

    Directory of Open Access Journals (Sweden)

    Kaja Žuran

    2013-12-01

    Full Text Available We live in a post-modern society, an information society, a society based around knowledge and participation, and above all in a media society. In a media culture where media holds a dominant position, we cannot overlook the emerging idea of a ‘media divide’ within the frame of media education, media literate individuals and the expansion of the traditional concept of media literacy. Firstly, we are in an era of technological revolution, and it is time to consider the meaning and function of media and how we experience it in our everyday life. Secondly, as a society we are subject to intense media invasion and we all need to learn how to use it to our benefit and apply a critical and autonomous perspective towards selecting media content. Otherwise the media divide between the media literate and illiterate will widen; but is there even a chance to overcome the supposed divide between those who are formally media educated and those who are not?

  18. Firn Structure Evolution at WAIS Divide

    Science.gov (United States)

    Harwell, E. N.; Albert, M. R.; Gregory, S.; Keegan, K. M.

    2013-12-01

    The polar ice sheets serve as natural archives of past climate, as well as sensitive indicators of current climate change. The physical structure of snow and firn is sensitive to local environmental changes. The top 60-120 m of wide expanses of the Greenland and Antarctic ice sheets consists of firn, snow that is more than a year old. This porous structure serves as a natural archive of past atmospheric composition and plays an important role in the initiation of the ice core record of past atmospheres, and also plays a key role in remote sensing. This paper examines the physical nature of firn at the WAIS Divide ice core site in West Antarctica. Measurements of the density and permeability profiles are reported from the surface over the depth of the firn column profile. The WAIS Divide ice core site was chosen to be the Antarctic analog of the high-resolution GISP2 core from Summit, Greenland; both sites are cold sites with high accumulation rates. We describe similarities and differences in the structure of firn by comparing measurements from WAIS Divide and Summit, and we identify causes for differences.

  19. New style of photomultiplier tube voltage divider

    International Nuclear Information System (INIS)

    An adjustable voltage divider chain has been developed for use with five-inch PM tubes in a neutron time-of-flight detector array. Best time response and pulse shape discrimination are obtained by maintaining high fixed gradients from the cathode to third dynode. Best saturation characteristics are obtained by maintaining high fixed gradient for the last several dynodes and the anode. Gain adjustments are made by reducing the voltage gradients in the non-critical central dynodes while simultaneously reducing the total tube voltage such that all tubes in the array can be powered by a common supply. (orig.)

  20. Long-term Correlations and 1/f^alpha Noise in the Steady States of Multi-Species Resistor Networks

    CERN Document Server

    Pennetta, C; Reggiani, L

    2007-01-01

    We introduce a multi-species network model which describes the resistance fluctuations of a resistor in a non-equilibrium stationary state. More precisely, a thin resistor characterized by a 1/f^alpha resistance noise is described as a two-dimensional network made by different species of elementary resistors. The resistor species are distinguished by their resistances and by their energies associated with thermally activated processes of breaking and recovery. Depending on the external conditions, stationary states of the network can arise as a result of the competition between these processes. The properties of the network are studied as a function of the temperature by Monte Carlo simulations carried out in the temperature range 300 \\div 800 K. At low temperatures, the resistance fluctuations display long-term correlations expressed by a power-law behavior of the auto-correlation function and by a value approx 1 of the alpha-exponent of the spectral density. On the contrary, at high temperatures the resista...

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

    Science.gov (United States)

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

    2003-03-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  3. Actividades de experimentación con materiales de bajo coste para la enseñanza de física: resistores y capacitores de grafito

    Directory of Open Access Journals (Sweden)

    Marcos Alfredo Salami

    2007-04-01

    Full Text Available This work presents an investigation carried out at the Pontifical Catholic University of Rio Grande do Sul from April 2002 to December 2003, involving the feasibility of using resistors and capacitors made of graphite laid upon paper, cardboard and plastic, in order to help the learning of electricity through experimentation. Its specific focus was the contents on resistibility, calculation of equivalent resistance of serial and parallel associations of resistors and capacitors, dependence of capacitance to the area, to the distance between the boards and the shape of the boards. The low cost technique resulting from this development allows students to playfully manipulate variables involved in the definition of electric resistance and capacitance, besides making it possible for them to crate and modify freely the associations of resistors andcapacitors, by just using a multimeter with a capacimeter function, paper and a 6B type pencil. It also has a great potential to stimulate the comprehension and learning process of such contents once it is pleasant, simple and low costly. It also promotes the engagement and free participation of all students. Graphite has already been used in the production of resistors to measure individual resistance and associations as described in the article by (Rocha Filho et al., 2004, and also in the production of capacitors to measure the capacitances in the activities mentioned in the master’s dissertation of (Salami, 2004.

  4. Substrate temperature and resistivity of Mn and Mn-MgF2 thin film resistors

    International Nuclear Information System (INIS)

    Pure Mn and Mn/MgF2 cermet film resistors, 25, 50 and 100nm thick have been prepared at various substrate temperatures 295-455K. The films contained 100 and 39 Vol% Mn. The evaporant mixtures were evaporated from a single boat evaporation source at a pressure of 10-5 torr. The electrical resistivities of the films were measured at the deposition temperatures and found to be between 110 and 1500??-cm. The films were ohmic, they have a negative temperature coefficient of resistance and a low activation energy for conduction (19-82meV). A possible electronic conduction mechanism in the films was suggested to be thermal activated tunnelling. (author)

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

    DEFF Research Database (Denmark)

    Bak, Claus Leth; da Silva, Filipe Miguel Faria

    2009-01-01

    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.

  6. Biomolecular Structure Determination with Divide and Concur

    Science.gov (United States)

    Kallus, Yoav; Elser, Veit

    2009-03-01

    Divide and concur (D-C) is a general computational approach, designed for the solution of highly frustrated problems. Recently applied to the problems of disk packing, the kissing number problem, and 3-SAT, it was competitive or outperformed special-purpose methods.ootnotetextS. Gravel and V. Elser, Phys. Rev. E 78, 036706 (2008) We present a method for applying the D-C framework to the problem of biomolecular structure determination. From a list of geometric constraints on groups of atoms in the molecule, we construct a deterministic iterative map that efficiently searches for structures simultaneously satisfying all constraints. As our method eschews an energy function and its minimization to focus on geometric constraints, it can very naturally integrate with the geometric constraints due to chemistry and physics, experimental constraints due to NMR data or many other experimental or biological hints. We present some results of our method.

  7. The Bread Book Multiplying and Dividing

    CERN Document Server

    Hyland, Tony

    2008-01-01

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

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

    Science.gov (United States)

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

    2014-03-28

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

  9. 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)

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

    1017-10-01

    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 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 predictions indicated a much more frequent water release from root

  10. Measurement of small ion beams by thermal ionisation mass spectrometry using new 10{sup 13} Ohm resistors

    Energy Technology Data Exchange (ETDEWEB)

    Koornneef, J.M., E-mail: j.m.koornneef@vu.nl [Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1085, 1081HV Amsterdam (Netherlands); Bouman, C.; Schwieters, J.B. [Thermo Fisher Scientific, Hanna-Kunath-Str. 11, Bremen, 28199 (Germany); Davies, G.R. [Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1085, 1081HV Amsterdam (Netherlands)

    2014-03-01

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

  11. Digital Divide: Issues Facing Adult Learners

    Directory of Open Access Journals (Sweden)

    Ramesh Rao

    2009-02-01

    Full Text Available Normal 0 7.8 ? 0 2 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:????; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} Technology had enabled many adult to pursue their education. However, technology changes in terms of type and accessing had caused “digital divide” (DD to exist among students of all ages. In this paper, issues which should be incorporated in measuring digital divide for adult learners are discussed. The issues which are discussed in this paper are age, gender and income. Why these issues should be included in evaluating DD are examined.

  12. Can Water Store Charge?

    OpenAIRE

    Ovchinnikova, Kate; Pollack, Gerald H.

    2009-01-01

    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...

  13. Bridging the divide between science and journalism.

    Science.gov (United States)

    Van Eperen, Laura; Marincola, Francesco M; Strohm, Jennifer

    2010-01-01

    There are countless reasons nearly every scientist should learn how to communicate effectively with the media, including increased understanding of critical research findings to attract or sustain funding and build new professional partnerships that will further propel forward research. But where do scientists begin? Bridging the Divide between Science and Journalism offers practical tips for any scientist looking to work with the media.Given the traditional and internet-based sources for medical research and healthcare-related news now available, it is imperative that scientists know how to communicate their latest findings through the appropriate channels. The credible media channels are managed by working journalists, so learning how to package vast, technical research in a form that is appetizing and "bite-sized" in order to get their attention, is an art. Reducing years of research into a headline can be extremely difficult and certainly doesn't come naturally to every scientist, so this article provides suggestions on how to work with the media to communicate your findings. PMID:20219123

  14. Bridging the Divide between Science and Journalism

    Directory of Open Access Journals (Sweden)

    Marincola Francesco M

    2010-03-01

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

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

    International Nuclear Information System (INIS)

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

  16. Variable resistor made by repeated steps of epitaxial deposition and lithographic structuring of oxide layers by using wet chemical etchants

    Science.gov (United States)

    Weber, Dieter; V?fély, Róza; Chen, Yuehua; Mourzina, Yulia; Poppe, Ulrich

    2013-04-01

    Variable resistors were constructed from epitaxial SrRuO3 (SRO), La0.67Sr0.33MnO3 (LSMO) and SrTiO3 layers with perovskite crystal structure. Each layer was patterned separately by lithographic methods. Optimized wet chemical etchants and several polishing steps in organic solvents allowed good epitaxy of subsequent layers, comparable to epitaxy on pristine substrates. Periodate as the oxidizing agent for SRO and iodide with ascorbic acid as the reducing agents for LSMO were used to attack these chemically resistant oxides. The final devices changed their conductance in a similar manner to previously described variable resistors that were defined with shadow masks.

  17. Simulasi Dinamika untuk Menentukan Stabilitas Sistem Tenaga Listrik Menggunakan Thyristor Controlled Braking Resistor pada Sistem IEEE 34 Node Test Feeder

    Directory of Open Access Journals (Sweden)

    Andi Taufiq

    2012-09-01

    Full Text Available Terdapat berbagai macam metode untuk meningkatkan stabilitas sistem  tenaga listrik. Salah satunya adalah dengan menggunakan metode pengereman dinamis (dynamic braking. Generator sinkron sebagai distributed generator yang digerakkan oleh mesin diesel. Pada saat terjadi gangguan pada sistem, digunakan sebuah Thyristor Controlled Braking Resistor (TCBR untuk meredam osilasi yang terjadi. Sistem yang hendak dianalisis dinamika dan stabilitasnnya adalah IEEE 34 node test feeder. Dengan sistem ini diilustrasikan karakteristik dan keefektifan TCBR untuk meredam osilasi frekuensi rendah dan mencegah terjadinya ketidakstabilan transien sistem. Dari hasil analisis diperoleh bahwa dengan adanya penambahan TCBR (Thyristor Controlled Braking Resistor maka respon transien sistem akan menjadi lebih baik. Hal ini ditunjukkan dengan adanya penurunan overshoot dan settling timenya. Dengan demikian sistem akan menuju kondisi stabil dengan lebih cepat setelah terjadi gangguan.

  18. 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

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

    OpenAIRE

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

    2013-01-01

    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...

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

    OpenAIRE

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

    2014-01-01

    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 ...

  1. Doped nanocrystalline ZnO powders for non-linear resistor applications by spray pyrolysis method.

    Science.gov (United States)

    Hembram, Kaliyan; Vijay, R; Rao, Y S; Rao, T N

    2009-07-01

    Homogeneous and doped nanocrystalline ZnO powders (30-200 nm) were synthesized by spray pyrolysis technique. The spray pyrolysed powders were calcined in the temperature range of 500-750 degrees C. Formation of insulating pyrochlore phase started from 700 degrees C during the calcination itself. The calcined powders were compacted and sintered at different temperatures ranging from 900-1200 degrees C for 0.5-4 h. The densification behavior was found to be dependent on calcination temperature of the nanopowder. The resulting discs were found to have density (5.34-5.62 g/cc) in the range of 96-99% of theoretical density. The breakdown voltage value obtained for the nanopowder based non-linear resistor is 10.3 kV/cm with low leakage current density of 0.7 microA/cm2 and coefficient of nonlinearity as high as 193. The activation energy for grain growth of the doped ZnO nanopowder powders is 449.4 +/- 15 kJ/mol. PMID:19916460

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

    Directory of Open Access Journals (Sweden)

    Arun Kumar Sunaniya

    2013-07-01

    Full Text Available 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 is 207.987 ?watts;Power delay product (PDP is 415.9 fWs, and the area is 1.89?m2. The second and third approaches areclocked SIS ADC and Sleep transistor SIS ADC. Both of them show significant improvement in powerdissipation as 57.5% & 71% respectively. Whereas PDP is 229.7 fWs and area is 0.05 ?m2 for Clocked SISADC and 107.3 fWs & 1.94 ?m2 for Sleep transistor SIS ADC.

  3. Low power, lightweight vapor sensing using arrays of conducting polymer composite chemically-sensitive resistors

    Science.gov (United States)

    Ryan, M. A.; Lewis, N. S.

    2001-01-01

    Arrays of broadly responsive vapor detectors can be used to detect, identify, and quantify vapors and vapor mixtures. One implementation of this strategy involves the use of arrays of chemically-sensitive resistors made from conducting polymer composites. Sorption of an analyte into the polymer composite detector leads to swelling of the film material. The swelling is in turn transduced into a change in electrical resistance because the detector films consist of polymers filled with conducting particles such as carbon black. The differential sorption, and thus differential swelling, of an analyte into each polymer composite in the array produces a unique pattern for each different analyte of interest, Pattern recognition algorithms are then used to analyze the multivariate data arising from the responses of such a detector array. Chiral detector films can provide differential detection of the presence of certain chiral organic vapor analytes. Aspects of the spaceflight qualification and deployment of such a detector array, along with its performance for certain analytes of interest in manned life support applications, are reviewed and summarized in this article.

  4. Circular resistor networks for electrical impedance tomography with partial boundary measurements

    International Nuclear Information System (INIS)

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

  5. Intermittent Phonon Scattering as a Possible Origin of 1/f Fluctuations in Metallic Resistors

    Science.gov (United States)

    Grüneis, Ferdinand

    2015-04-01

    We regard a metallic resistor for temperatures T ? ?D (= Debye temperature); under this condition, electron-phonon scattering is the dominant scattering mechanism. We investigate the noise properties under the supposition that phonon scattering is an intermittent process. Intermissions may be caused by an interaction between different phonon modes giving rise to a short break down of a mode. Due to such an intermittent behavior, we obtain — besides thermal noise — a 1/f noise component. Under equilibrium conditions, the 1/f noise term disappears. Under an applied electric field, the electrons are accelerated between collisions resulting in an additional 1/f noise component which can be compared with Hooge's relation. The predicted Hooge coefficient is ? ? 3 ? 10-3(?off/?s)2 with ?s being the mean electron phonon scattering time and ?off being the mean off-time ( = intermission). We also find 1/f fluctuations in the square of thermal noise suggesting that an applied current only probes 1/f fluctuations which are already present under equilibrium conditions.

  6. 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

  7. Bridging the Digital Divide: – A Myth or Reality ?

    OpenAIRE

    Zablon Akoko Mbero; Sampson Dankyi ASARE

    2013-01-01

    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 ...

  8. A Compound Generic Quantitative Framework for Measuring Digital Divide

    OpenAIRE

    Noureldien A. Noureldien

    2014-01-01

    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...

  9. Design of shielded voltage divider for impulse voltage measurement

    International Nuclear Information System (INIS)

    The dividers used for the study of the insulation and electric discharge phenomena in high voltage equipments have the problems of the change of response characteristics owing to adjacent bodies and of induced noise. To improve the characteristics, the enclosed type divider shielded with metal has been investigated, and the divider of excellent response has been obtained by adopting the frequency-separating divider system, which is divided into two parts, resistance divider (lower frequency region) and capacitance divider (higher frequency region), for avoiding to degrade the response. Theoretical analysis was carried out in the cases that residual inductance can be neglected or can not be neglected in the small capacitance divider, and that the connecting wires are added. Next, the structure of the divider and the design of the electric field for the divider manufactured on the basis of the theory are described. The response characteristics were measured. The results show that 1 MV impulse voltage can be measured within the response time of 10 ns. Though this divider aims at the impulse voltage, the duration time of which is about that of standard lightning impulse, in view of the heat capacity because of the input resistance of 10.5 k?, it is expected that the divider can be applied to the voltage of longer duration time by increasing the input resistance in future. (Wakatsuki, Y.)

  10. 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 ...

  11. A unified resistor-capacitor model for impedance, dielectrophoresis, electrorotation, and induced transmembrane potential.

    Science.gov (United States)

    Gimsa, J; Wachner, D

    1998-08-01

    Dielectric properties of suspended cells are explored by analysis of the frequency-dependent response to electric fields. Impedance (IMP) registers the electric response, and kinetic phenomena like orientation, translation, deformation, or rotation can also be analyzed. All responses can generally be described by a unified theory. This is demonstrated by an RC model for the structural polarizations of biological cells, allowing intuitive comparison of the IMP, dielectrophoresis (DP), and electrorotation (ER) methods. For derivations, cells of prismatic geometry embedded in elementary cubes formed by the external solution were assumed. All geometrical constituents of the model were described by parallel circuits of a capacitor and a resistor. The IMP of the suspension is given by a meshwork of elementary cubes. Each elementary cube was modeled by two branches describing the current flow through and around the cell. To model DP and ER, the external branch was subdivided to obtain a reference potential. Real and imaginary parts of the potential difference of the cell surface and the reference reflect the frequency behavior of DP and ER. The scheme resembles an unbalanced Wheatstone bridge, in which IMP measures the current-voltage behavior of the feed signal and DP and ER are the measuring signal. Model predictions were consistent with IMP, DP, and ER experiments on human red cells, as well as with the frequency dependence of field-induced hemolysis. The influential radius concept is proposed, which allows easy derivation of simplified equations for the characteristic properties of a spherical single-shell model on the basis of the RC model. PMID:9675212

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

    OpenAIRE

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

    2012-01-01

    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...

  13. Zones of silence: A framework beyond the digital divide

    OpenAIRE

    Potter, Amelia Bryne

    2006-01-01

    There is no doubt that much digital divide work — including connectivity initiatives, technology transfer programs, and other projects — is done with good intention. Yet, as has been widely recognized, the conceptual framework of the digital divide is limiting. The language of the digital divide not only places people into simplistic “have”/“have not” categories, making assumptions about the solution to “information poverty” with little attention to local contexts, its logic a...

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

    Science.gov (United States)

    Aghili Yajadda, Mir Massoud

    2014-10-01

    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.

  15. 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)

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

    2014-10-21

    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.

  16. 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.

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

    Science.gov (United States)

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

    2012-12-01

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

  18. Variable resistor made by repeated steps of epitaxial deposition and lithographic structuring of oxide layers by using wet chemical etchants

    OpenAIRE

    Weber, Dieter; Vo?fe?ly, Ro?za; Chen, Yuehua; Mourzina, Yulia; Poppe, Ulrich

    2013-01-01

    Variable resistors were constructed from epitaxial SrRuO3 (SRO), La0.67Sr0.33MnO3 (LSMO) and SrTiO3 layers with perovskite crystal structure. Each layer was patterned separately by lithographic methods. Optimized wet chemical etchants and several polishing steps in organic solvents allowed good epitaxy of subsequent layers, comparable to epitaxy on pristine substrates. Periodate as the oxidizing agent for SRO and iodide with ascorbic acid as the reducing agents for LSMO were...

  19. Development and characterisation of silicon photomultipliers with bulk-integrated quench resistors for future applications in particle and astroparticle physics

    International Nuclear Information System (INIS)

    This thesis deals with the development and characterisation of a novel silicon photomultiplier concept with bulk-integrated quench resistors. The approach allows the realisation of a free entrance window and high fill factors, which leads to an improvement of the detection efficiency. With first prototype productions a proof of concept was possible. A full characterisation provided promising results, in particular with respect to the photon detection efficiency. By customising the simulation tools, a reliable description of the devices was achieved. In addition, conceptual studies of the next device generation demonstrated the possibility of single cell readout, expanding the application range of those detectors to particle tracking.

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

    Scientific Electronic Library Online (English)

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

    2013-12-01

    Full Text Available 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.

  1. Robust Platinum Resistor Thermometer (PRT) Sensors and Reliable Bonding for Space Missions

    Science.gov (United States)

    Cucullu, Gordy C. III; Mikhaylov, Rebecca; Ramesham, Rajeshuni; Petkov, Mihail; Hills, David; Uribe, Jose; Okuno, James; De Los Santos, Greg

    2013-01-01

    Platinum resistance thermometers (PRTs) provide accurate temperature measurements over a wide temperature range and are used extensively on space missions due to their simplicity and linearity. A standard on spacecraft, PRTs are used to provide precision temperature control and vehicle health assessment. This paper reviews the extensive reliability testing of platinum resistor thermometer sensors (PRTs) and bonding methods used on the Mars Science Laboratory (MSL) mission and for the upcoming Soil Moisture Active Passive (SMAP) mission. During the Mars Exploration Rover (MER) mission, several key, JPL-packaged PRTs failed on those rovers prior to and within 1-Sol of landing due to thermally induced stresses. Similar failures can be traced back to other JPL missions dating back thirty years. As a result, MSL sought out a PRT more forgiving to the packaging configurations used at JPL, and extensively tested the Honeywell HRTS-5760-B-U-0-12 sensor to successfully demonstrate suitable robustness to thermal cycling. Specifically, this PRT was cycled 2,000 times, simulating three Martian winters and summers. The PRTs were bonded to six substrate materials (Aluminum 7050, treated Magnesium AZ231-B, Stainless Steel 304, Albemet, Titanium 6AL4V, and G-10), using four different aerospace adhesives--two epoxies and two silicones--that conformed to MSL's low out-gassing requirements. An additional epoxy was tested in a shorter environmental cycling test, when the need for a different temperature range adhesive was necessary for mobility and actuator hardware late in the fabrication process. All of this testing, along with electrostatic discharge (ESD) and destructive part analyses, demonstrate that this PRT is highly robust, and not subject to the failure of PRTs on previous missions. While there were two PRTs that failed during fabrication, to date there have been no in-flight PRT failures on MSL, including those on the Curiosity rover. Since MSL, the sensor has gone through a change in construction such that the manufacturer significantly restricts the minimum temperature. However, significant subsequent testing was performed with this new version of the part to show that it indeed is still robust to at least Mars minimum temperatures of -135 degrees Centigrade. The additional completed testing will be described. This work has resulted in a successful sensor package qualification and a reliable bonding method suitable for use over large temperature extremes

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

    Scientific Electronic Library Online (English)

    Teresa Vaz, Martins; Raúl, Toral.

    2012-06-01

    Full Text Available 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.

  3. Addressing the Research/Practice Divide in Teacher Education

    Science.gov (United States)

    Flessner, Ryan

    2012-01-01

    Educational scholars often describe a research/practice divide. Similarly, students in teacher education programs often struggle to navigate the differences between university coursework and expectations they face in field-based placements. This self-study analyzes one researcher's attempt to address the research/practice divide from the position…

  4. The Digital Divide in Health Education: Myth or Reality?

    Science.gov (United States)

    Stellefson, Michael; Chaney, Beth; Chaney, Don

    2008-01-01

    Although e-health interventions provide new opportunities for health education, there has been cause for concern regarding the purported information technology gap between those who have access to digital applications and those who do not--termed the "digital divide." The literature suggests, however, that this divide may now be illusory, driven…

  5. [Design of broadband power divider in microwave hyperthermia system].

    Science.gov (United States)

    Sun, Bing; Jiang, Guotai; Lu, Xiaofeng; Cao, Yi

    2010-10-01

    In clinical application of microwave hyperthermia, multi-applicators are often simultaneously required to irradiate the tumor because of its large volume or its deep location. Power divider separates the input microwave energy into equal, or unequal, energy to each applicator. In this paper, the design procedure for the three-section transmission-line transformer based one-to-two equal-split Wilkinson power divider is introduced. By impedance analysis on equivalent scheme, the design parameter of power divider is provided, and by simulation and optimization on Ansoft HFSS, a microstrip structure Wilkinson power divider operating frequency 2. 45 GHz is given. Measurement test results from network analyzer show that it has 25% bandwidth and good isolation in output with this structure. Besides, it is characterized by small size and easy processing. This power divider suits microwave hyperthermia. PMID:21089651

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

    International Nuclear Information System (INIS)

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

  7. 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

  8. Geology of photo linear elements, Great Divide Basin, Wyoming

    Science.gov (United States)

    Blackstone, D. L., Jr.

    1973-01-01

    The author has identified the following significant results. Ground examination of photo linear elements in the Great Divide Basin, Wyoming indicates little if any tectonic control. Aeolian aspects are more widespread and pervasive than previously considered.

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

    Directory of Open Access Journals (Sweden)

    Patrick C-H Soh

    2012-12-01

    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.

  10. Annan warns of 'content divide' between rich and poor

    CERN Multimedia

    Dickson, D

    2003-01-01

    "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)

  11. HIV infection of non-dividing cells: a divisive problem

    Directory of Open Access Journals (Sweden)

    Fassati Ariberto

    2006-10-01

    Full Text Available Abstract Understanding how lentiviruses can infect terminally differentiated, non-dividing cells has proven a very complex and controversial problem. It is, however, a problem worth investigating, for it is central to HIV-1 transmission and AIDS pathogenesis. Here I shall attempt to summarise what is our current understanding for HIV-1 infection of non-dividing cells. In some cases I shall also attempt to make sense of controversies in the field and advance one or two modest proposals.

  12. Wireless Technologies Bridging the Digital Divide in Education

    OpenAIRE

    Gerard Smyth

    2006-01-01

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

  13. Recursive Active Filter with Metamaterial Unequal Wilkinson Power Dividers

    OpenAIRE

    Aznar Ballesta, Francisco; Garci?a Pe?rez, Oscar Alberto; Gonza?lez Posadas, Vicente; Segovia Vargas, Daniel

    2010-01-01

    In this work, it is shown that it is possible to implement an unequal Wilkinson power divider with reduced dimensions by using metamaterial transmission lines based on complementary split ring resonators (CSRRs), in planar technology. In addition, this combiner has been used to implement a compact recursive active filter. Thanks to the use of the metamaterial combiner it is possible obtain a filter with small dimensions. Additionally, due to the asymmetry in the power divider it is possible o...

  14. Manufacturing of precise resistors on the base Ni-P and Ni-W-P layers by means of chemical reduction method

    International Nuclear Information System (INIS)

    Chemical preparation method of Ni-P and Ni-W-P layers on resistive ceramics has been worked out. The method base on chemical reduction in aqueous solution. The composition of the initial solutions determine the properties of obtained metal layers and electrical properties of resistor in consequence. 5 refs

  15. Romania's Digital Divide and the Failures of E-Government

    Directory of Open Access Journals (Sweden)

    Sorin Dan ?ANDOR

    2006-02-01

    Full Text Available This paper tries to measure the level of the digital divide existing in Romania and also to verify its relationship with e-government. At the country level, Romania is one of the least digitally developed countries in Europe, but it has shown a sharp increase in recent years. At the social level, based on data from public opinion surveys, digital divide is analyzed at two levels: lack of access and lack of knowledge. The results are similar to those in other countries: digital divide appears along the same dimensions: rural/urban, age, education, wealth and, to a lesser extent, gender. E-government services, while presumed to be at an adequate level, are used only by a very small number of citizens, thus having no impact upon the digital divide. Confronted with a serious divide, and with great possibility of its increasing, Romania needs to promote policies designed to increase access and knowledge. Also, e-government is not possible, unless administrative culture and procedures change.

  16. Bridging the Divide: Translating Landsat Research Into Usable Science

    Science.gov (United States)

    Rocchio, L. E.; Davis, A. L.

    2006-12-01

    Science has long served humankind. Breakthroughs in medicine have increased longevity and advances in technology have made modern-day conveniences possible. Yet, social benefits begotten by the environmental sciences, although critical for the survival of humanity, have not always been as widely recognized or used. To benefit today's rapidly growing population, the divides between environmental research, applied environmental science, and use of this information by decision makers must be bridged. Lessons about the translation from research to usable science can be learned from the four decades of Landsat history, and these lessons can serve as useful models for bridging the gaps between new technology, scientific research, and the use of that research and technology in real-world problem solving. In 1965, William Pecora, then-director of the U.S. Geological Survey, proposed the idea of a remote sensing satellite program to gather facts about natural resources of Earth. For the next seven years, an intense campaign showing the depth and diversity of satellite imagery applications was waged. This led to the 1972 launch of the first civilian land-observing satellite, Landsat 1. By 1975, successful application research based on Landsat 1 imagery prompted then-NASA Administrator Dr. James Fletcher to proclaim that if one space age development would save the world, it would be Landsat and its successor satellites. Thirty-four years of continual Landsat imaging and related-research has lead to the implementation of many socially beneficial applications, such as improved water management techniques, crop insurance fraud reduction, illicit crop inventories, natural disaster relief planning, continent-scale carbon estimates, and extensive cartographic advances. Despite these successes, the challenge of translating Landsat research into realized social benefits remains. Even in this geospatially-savvy era, the utility of Landsat largely escapes policymakers. Here, in an effort to better understand these challenges, we dissect the anatomy of some of Landsat's social benefit success stories and draw on the advice of Landsat experts to outline some of the important steps needed to facilitate the recognition of usable environmental science.

  17. Transition State Theory for dissipative systems without a dividing surface

    CERN Document Server

    Revuelta, F; Benito, R M; Borondo, F

    2015-01-01

    Transition State Theory is a central cornerstone in reaction dynamics. Its key step is the identification of a dividing surface that is crossed only once by all reactive trajectories. This assumption is often badly violated, especially when the reactive system is coupled to an environment. The calculations made in this way then overestimate the reaction rate and the results depend critically on the choice of the dividing surface. In this Letter, we study the phase space of a stochastically driven system close to an energetic barrier in order to identify the geometric structure unambiguously determining the reactive trajectories, which is then incorporated in a simple rate formula for reactions in condensed phase that is both independent of the dividing surface and exact.

  18. Water

    Science.gov (United States)

    ... 1986 and 1996 amendments to the Safe Drinking Water Act ( http://www.epa.gov/safewater/sdwa/index.html ) ... for 1–2 minutes ; b . Then, fill a clean container(s) with water from this tap. This water will be suitable ...

  19. Google and the digital divide the bias of online knowledge

    CERN Document Server

    Segev, Elad

    2010-01-01

    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

  20. Peculiarities of the Digital Divide in Sub-Saharan Africa

    Science.gov (United States)

    Mutula, Stephen M.

    2005-01-01

    Purpose: Seeks to argue that the peculiarities of sub-Saharan Africa, in terms of its socio-cultural diversity, low economic development, linguistic factors, HIV/AIDS pandemic, gender discrimination, low ICT awareness and so on, demand a new model of addressing the digital divide. Design/methodology/approach: Paper largely based on literature…

  1. Teachers in the Social Trenches: Teaching Civics in Divided Societies

    Science.gov (United States)

    Tamir, Yuli

    2015-01-01

    This article argues that in divided societies, civic education fails to fulfill one of its most important social role: creating a more inclusive society that allows a democratic dialogue to flow across different ideological, religious, and cultural communities. This failure is grounded in two main reasons. First, civics teachers are socially and…

  2. Response Styles and the Rural-Urban Divide

    Science.gov (United States)

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

    2014-01-01

    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…

  3. Evidence of a divided-attention advantage in autism.

    Science.gov (United States)

    Rutherford, M D; Richards, Eric D; Moldes, Vanessa; Sekuler, Allison B

    2007-07-01

    People with autism spectrum disorders appear to have some specific advantages in visual processing, including an advantage in visual search tasks. However, executive function theory predicts deficits in tasks that require divided attention, and there is evidence that people with autism have difficulty broadening their attention (Mann & Walker, 2003). We wanted to know how robust the known attentional advantage is. Would people with autism have difficulty dividing attention between central and peripheral tasks, as is required in the Useful Field of View task, or would they show an advantage due to strengths in visual search? Observers identified central letters and localized peripheral targets under both focused- and divided-attention conditions. Participants were 20 adults with high-functioning autism and Asperger's syndrome and 20 adults matched to the experimental group on education, age, and IQ. Contrary to some predictions, individuals with autism tended to show relatively smaller divided-attention costs than did matched adults. These results stand in stark contrast to the predictions of some prevalent theories of visual and cognitive processing in autism. PMID:18416504

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

    Science.gov (United States)

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

    2012-01-01

    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…

  5. The Learning Computer: Low Bandwidth Tool that Bridges Digital Divide

    Science.gov (United States)

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

    2007-01-01

    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,…

  6. Dividable membrane with multi-reaction wells for microarray biochips.

    Science.gov (United States)

    Chang, Yaw-Jen; Hu, Chih-Yu; Yin, Li-Te; Chang, Cheng-Hao; Su, Hung-Ju

    2008-07-01

    This paper presents a multi-well membrane fabricated using polydimethylsiloxane (PDMS) as a part of a microarray biochip that allows dividable incubation chambers to be provided on a single chip. The conditions of the forming temperature, time, and mixing proportion of the materials were investigated to obtain optimal physical absorption with the surface of the chip substrate. To verify the properties of the multi-well chip, immunoassays were performed by the alpha-1-fetoprotein (AFP) antigen sandwich experiment. The results showed that the detection limit reached to the concentration of 10 ng/ml AFP antigen, and that the dynamic range was 30-3000 ng/ml. Attaining excellent physical absorption helps in avoiding cross-contamination or interference between different samples on the same biochip. The merits of dividable multi-well chips include promoting effective use of surface and multiple-sample experiments. PMID:18691532

  7. Beyond artificial intelligence the disappearing human-machine divide

    CERN Document Server

    Zackova, Eva; Kelemen, Jozef

    2015-01-01

    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...

  8. The Multicultural Pavillion: EdTech & Digital Divide

    Science.gov (United States)

    The Multicultural Pavillion is part of EdChange, a website is founded and maintained by Paul C. Gorski, Ph.D., which provides "resources and dialogue for equity in education." This section on Ed Tech & Digital Divide offers online resources and articles on the digital divide and multicultural e-learning. Gorksi has also posted a 28-page report that combines various conference presentations, articles, and research he has done over the past three years on Multicultural Education and the Internet: Tools, Resources, and Commentary. Other sections of the Multicultural Pavillion offer listservs, historical documents, news updates, awareness activities, a poetry journal, movie reviews, songs for initiating multicultural dialogue, a working definition of multicultural education, and other resources on multicultural education and teacher action research.

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

    Directory of Open Access Journals (Sweden)

    Doris G. Johnson

    2005-09-01

    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.

  10. 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.

  11. Development in Sub-Saharan Africa: Overcoming the Digital Divide

    OpenAIRE

    Oyedokun Agbeja; R.O. Salawu

    2007-01-01

    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...

  12. Trope Theory on the Mental/Physical Divide

    OpenAIRE

    Trettin, Ka?the

    2002-01-01

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

  13. BRIDGING THE KNOWLEDGE DIVIDE Educational Technology for Development

    OpenAIRE

    Reviewed by Ozlem OZAN,

    2009-01-01

    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 ...

  14. Divided screen : the doppelgänger in German silent film

    OpenAIRE

    Rashidi, Bahareh

    2007-01-01

    The proliferation of the doppelgänger theme in so many films of Wilhemine and Weimar Germany raises the question of its historical significance, in particular during Germany’s “crisis of classical modernity”. While previous studies have addressed the double from a narrative perspective, focusing on its psychological significations as divided self, this thesis instead considers the theme from a structural and historical perspective: how, as a technical reproduction of the...

  15. Adaptation Procedure for Multi-dividing Ontology Algorithm

    Directory of Open Access Journals (Sweden)

    Wei Gao

    2013-01-01

    Full Text Available Ontology, as a structured conceptual model of knowledge representation and storage, has widely used in computer science, biomedical and social science. Ontology algorithms even become the core algorithms in information retrieval and thus raise more and more attention. In this study, we propose the adaptation procedure for ontology algorithm in multi-dividing setting. The new technology helps to adapt an unknown parameter and we determine the generalization error bound for such adaptation procedure under certain assumption.

  16. Divide-and-Conquer with Sequential Monte Carlo

    OpenAIRE

    Lindsten, Fredrik; Johansen, Adam M.; Naesseth, Christian A.; Kirkpatrick, Bonnie; Schön, Thomas B.; Aston, John; Bouchard-Côté, Alexandre

    2014-01-01

    We develop a Sequential Monte Carlo (SMC) procedure for inference in probabilistic graphical models using the divide-and-conquer methodology. The method is based on an auxiliary tree-structured decomposition of the model of interest turning the overall inferential task into a collection of recursively solved sub-problems. Unlike a standard SMC sampler, the proposed method employs multiple independent populations of weighted particles, which are resampled, merged, and propaga...

  17. Preferences for Employment Protection and the Insider-Outsider Divide

    OpenAIRE

    Guillaud, Elvire; Marx, Paul

    2013-01-01

    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...

  18. Simplicial Differential Calculus, Divided Differences, and Construction of Weil Functors

    OpenAIRE

    Bertram, Wolfgang

    2011-01-01

    We define a simplicial differential calculus by generalizing divided differences from the case of curves to the case of general maps, defined on general topological vector spaces, or even on modules over a topological ring K. This calculus has the advantage that the number of evaluation points growths linearly with the degree, and not exponentially as in the classical, "cubic" approach. In particular, it is better adapted to the case of positive characteristic, where it perm...

  19. Measuring the component of a divide and conquer skeleton

    OpenAIRE

    Printista, Alicia Marcela; Saez, Fernando

    2009-01-01

    Current performance prediction analytical models try to characterize the performance behavior of actual machines through a small set of parameters. Due to different factors, the predicted times suffer substantial deviations. A natural approach is to associate a different proportionality constant with each basic block of computation. In particular, the paper deals with a skeleton designed for parallel divide and conquer algorithms that provide hypercubical communications among processes. Our p...

  20. Divided Dreamworlds? : The Cultural Cold War in East and West

    OpenAIRE

    Romijn, Peter; Scott-smith, Giles; Segal, Joes

    2012-01-01

    While the divide between capitalism and communism, embodied in the image of the Iron Curtain, seemed to be as wide and definitive as any cultural rift, Giles Scott-Smith, Joes Segal, and Peter Romijn have compiled a selection of essays on how culture contributed to the blurring of ideological boundaries between the East and the West. This important and diverse volume presents fascinating insights into the tensions, rivalries, and occasional cooperation between the two blocs, with essays that ...

  1. Learnings from investigations on SG divider plates: Coupling field characterizations with numerical mechanical simulation

    International Nuclear Information System (INIS)

    Nickel based alloys stress corrosion cracking (SCC) has been a major concern for the nuclear power plant utilities since the 1970s. Since 2002, SCC indications have been found on steam generator (SG) divider plates made of alloy 600 on French PWRs (pressurized water reactors) 900 MWe units. Although integrity is not questioned, many studies have been conducted to deepen understanding of the phenomenon. Among numerous studies to investigate the SCC damage phenomena, advanced mechanical analysis has been performed to improve the knowledge of the in-service loadings of the SG 900 MWe partition stub and divider plate. Manufacturing steps are taken into account, such as welding and the first hydro-test, to have a more precise description of the mechanical states in the vicinity of the welds where SCC is likely to occur. Recently, EDF hot laboratories made destructive examinations of a decommissioned SG. To fulfil the analyses computations have been carried out on the dedicated configuration. A 3D FE model, including the simulation of the welding and hydro-test, has been set up. Comparisons with experimental investigations on the divider plate of decommissioned SG have shown a good agreement between experimental and numerical results. These results emphasize the redistribution of weld residual stresses after the first hydro-test, and the effect of hydro-testing on the plastic deformation of the stub only in some specific cases of 900 MWe SG

  2. THE DIGITAL DIVIDE: ICT DEVELOPMENT INDICES IN MEXICO

    Directory of Open Access Journals (Sweden)

    Edgar TELLO-LEAL

    2012-01-01

    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.

  3. On Newman polynomials which divide no Littlewood polynomial

    Science.gov (United States)

    Dubickas, Arturas; Jankauskas, Jonas

    2009-03-01

    Recall that a polynomial P(x) in Z[x] with coefficients 0, 1 and constant term 1 is called a Newman polynomial, whereas a polynomial with coefficients -1, 1 is called a Littlewood polynomial. Is there an algebraic number alpha which is a root of some Newman polynomial but is not a root of any Littlewood polynomial? In other words (but not equivalently), is there a Newman polynomial which divides no Littlewood polynomial? In this paper, for each Newman polynomial P of degree at most 8, we find a Littlewood polynomial divisible by P . Moreover, it is shown that every trinomial 1+ux^a+vx^b, where aintegers and u, v in \\{-1,1\\}, so, in particular, every Newman trinomial 1+x^a+x^b, divides some Littlewood polynomial. Nevertheless, we prove that there exist Newman polynomials which divide no Littlewood polynomial, e.g., x^9+x^6+x^2+x+1. This example settles the problem 006:07 posed by the first named author at the 2006 West Coast Number Theory conference. It also shows that the sets of roots of Newman polynomials V_{N} , Littlewood polynomials V_{L} and \\{-1,0,1\\} polynomials V are distinct in the sense that between them there are only trivial relations V_{N}subset V and V_{L}subset V. Moreover, V ne V_{L} \\cup V_{N}. The proofs of several main results (after some preparation) are computational.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-02-15

    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.

  5. 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

  6. Effect of the ambient field on the I-V characteristics of nanowire resistors and junctions—A simulation study

    Science.gov (United States)

    Maheswaran, K. R. K.; Karmalkar, S.

    2011-12-01

    Ambient field refers to the field lines outside the semiconductor that are caused by the potential difference between points on the semiconductor. We present a TCAD study of the effects of the ambient field on the I- V characteristics of NanoWire (NW) resistors and junctions. The study covers different contact geometries, hi-lo as well as p-n junctions, and practical bias range including the equilibrium condition; effects of varying the wire radius, length, doping and ambient dielectric constant are brought out. The NWs studied have radii?15 nm and length?500 nm for which classical models based on drift-diffusion transport are applicable. Simple qualitative explanations for various non-linear shapes of the I- V characteristics are provided using field lines. An appealing analogy is presented for the rise in the carrier concentration of an undoped NW grown on a heavily doped substrate. The study is aimed at improving the understanding of nanoscale devices and proper interpretation of their experimental data.

  7. 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.

  8. Wireless Technologies Bridging the Digital Divide in Education

    Directory of Open Access Journals (Sweden)

    Gerard Smyth

    2006-06-01

    Full Text Available The objective of this paper is to demonstrate how the latest wireless standards and technologies may overcome the digital divide in education in the developed and developing worlds. The concept of the digital divide is discussed in the traditional socio-economic sense and expanded in terms of the learner's location, age, culture and background. It is important that we understand the full extent and complexities of this division if we are to effectively bridge it. Why and how the digital divide may be bridged is examined. Apart from the inherent inequalities that need to be addressed from an ethical perspective, it is very much in the interests of governments and citizens globally that Information and Communications Technology (ICT is made available to all as quickly and cost-effectively as possible. New forms of wireless protocols are overcoming challenges of terrain, infrastructure and finance. It is proposed that, by leveraging open broadband wireless standards, like Wireless Fidelity (Wi-Fi* and Worldwide Interoperability for Microwave Access (WiMAX*, and implementing Mobile Computing architecture, it is now possible to make dramatic strides in this direction. The paper continues with a general overview of these wireless standards and technologies followed by an in-depth look at Wi-Fi and WiMAX. The paper goes on to give examples of the Innovation Centre's involvement in delivering solutions and new usage models for eLearning that utilize the latest wireless standards and technologies. The challenges and successes of these projects are outlined and metrics are presented where available.

  9. A divide-and-conquer algorithm for identifying strongly connectedcomponents

    Energy Technology Data Exchange (ETDEWEB)

    Coppersmith, Don; Fleischer, Lisa; Hendrickson, Bruce; Pinar, Ali

    2003-03-27

    Strongly connected components of a directed graph can be found in an optimal linear time, by algorithms based on depth first search. Unfortunately, depth first search is difficult to parallelize. We describe two divide--and--conquer algorithms for this problem that have significantly greater potential for parallelization. We show the expected serial runtime of our simpler algorithm to be O(m log n), for a graph with n vertices and m edges. We then show that the second algorithm has O(mlog n) worst--case complexity.

  10. Divided Saphenectomy for Varicose Vein in Ambulatory Surgery

    OpenAIRE

    Yoh, Tomoaki; Okamura, Ryuji; Nakamura, Yuya; Kobayashi, Atsushi

    2014-01-01

    We performed divided saphenectomy (DS) for varicose vein in ambulatory surgery with minimal incisions. Under tumescent local anesthesia, this procedure ligates all perforators in the thigh, preserving a route of venous drainage, and reduces bruising by ligating all tributaries. Also, DS does not need any special surgical instrument. Subcutaneous inguinal hemorrhage was observed in 4.9% (3/61), mild bruises were observed in 19.7% (12/61), and saphenous nerve neuralgia was 1.6% (1/61). Wound in...

  11. Pump tank divider plate for sump suction sodium pumps

    International Nuclear Information System (INIS)

    A circular plate extends across the diameter of a sump suction pump, with a close clearance between the edge of the plate and the wall of the pump tank. The plate is located above the pump impeller, inlet and outlet flow nozzles but below the sodium free surface and effectively divides the pump tank into two separate chambers. On change of pump speed, the close fitting flow restriction plate limits the rate of flow into or out of the upper chamber, thereby minimizing the rate of level change in the tank and permitting time for the pump cover gas pressure to be varied to maintain an essentially constant level. 4 claims, 3 figures

  12. Transition duct with divided upstream and downstream portions

    Energy Technology Data Exchange (ETDEWEB)

    McMahan, Kevin Weston; LeBegue, Jeffrey Scott; Maldonado, Jaime Javier; Dillard, Daniel Jackson; Flanagan, James Scott

    2015-07-14

    Turbine systems are provided. In one embodiment, a turbine system includes a transition duct comprising an inlet, an outlet, and a duct passage extending between the inlet and the outlet and defining a longitudinal axis, a radial axis, and a tangential axis. The outlet of the transition duct is offset from the inlet along the longitudinal axis and the tangential axis. The duct passage includes an upstream portion extending from the inlet and a downstream portion extending from the outlet. The turbine system further includes a rib extending from an outer surface of the duct passage, the rib dividing the upstream portion and the downstream portion.

  13. CLOBAZAM SINGLE OR DIVIDED DOSE AGAINST DIAZEPAM IN ANXIETY NEUROSIS

    OpenAIRE

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

    1986-01-01

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

  14. Traffic Prediction Based on SVM Training Sample Divided by Time

    Directory of Open Access Journals (Sweden)

    Lingli Li

    2013-07-01

    Full Text Available In recent years, the volume of traffic is rapidly increasing. When vehicles running through the tunnel are more intensive or move slowly, the tunnel environment occurs deteriorated sharply, which affects the normal operation of the vehicle in the tunnel. This paper uses the result of previous mining association rules to select feature items and to establish four training samples divided by time. Then the training samples are utilized to create the SVM classification model. Finally the trained SVM model is used to prediction the tunnel traffic situation. Through traffic situation prediction, effective decisions can be made before traffic jams, and ensure that the tunnel traffic is normal.  

  15. Informaticiens Sans Frontières. Helping to bridge the Digital Divide

    CERN Multimedia

    Josiane Uwantege

    2009-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Jason Smith

    2009-06-01

    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.

  17. Water

    Science.gov (United States)

    ... or walk, especially on a hot day. Remember, water is a good way to add fluids to your daily routine without adding calories. Learn More: Important Nutrients to Know Healthy Lifestyle Related publications: Go4Life: Drinking Enough Fluids (PDF, 570K) ...

  18. 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

  19. Chirped and divided-pulse Sagnac fiber amplifier

    Science.gov (United States)

    Guichard, Florent; Zaouter, Yoann; Hanna, Marc; Mai, Khanh-Lin; Morin, Franck; Hönninger, Clemens; Mottay, Eric; Georges, Patrick

    2015-03-01

    Femtosecond fiber chirped pulse amplifiers have numerous advantages, but are limited in energy because of the small interaction area with the fiber core. In this contribution, we create two orthogonally-polarized stretched pulse replicas in the time domain, following the divided-pulse amplification (DPA) principle. This beam is subsequently separated into two counter-propagating beams in a Sagnac interferometer to finally generate four pulse replicas. These pulses are amplified in two state-of-the-art large mode area rod-type fiber amplifiers in series, before final coherent combination and compression. Because the stretched-pulse duration is of the order of hundreds of picoseconds, the DPA delay is induced using a freespace interferometer with reasonable arm lengths of few tens of centimeters. The use of a common interferometer to divide and recombine temporal pulse replicas, together with the Sagnac geometry, results in an identical optical path for all four replicas. Therefore, the whole spatio-temporal combining architecture is passive, avoiding the need for active electronic stabilization systems. Because we only use two temporal replicas, the system is immune to differential saturation levels or B-integrals between successive pulses: this is compensated by controlling the amplitude of both pulses at the input of the amplifying setup. This setup allows the generation of 1 mJ, 300 fs compressed pulses at 50 kHz repetition rate, corresponding to 50 W output average power, with a combining efficiency above 90% at all power levels.

  20. The Digital Divide: How Wide and How Deep?

    Directory of Open Access Journals (Sweden)

    Barbara F. Schloman

    2004-05-01

    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.

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

    International Nuclear Information System (INIS)

    Highlights: • Macromolecular materials were chosen to modify thermosetting polyimide (TSPI). • The formation of IPN structure in TSPI composite polymers was discussed. • The special mechanical properties required were the main study object. • The desired candidate materials should have proper hardness and toughness. • The specific mechanical data are quantitatively determined by experiments. - Abstract: 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.Y., E-mail: wxy@tju.edu.cn [School of Electronic Information Engineering, Tianjin University, Tianjin 300072 (China); Ma, J.X.; Li, C.G. [School of Electronic Information Engineering, Tianjin University, Tianjin 300072 (China); Wang, H.X. [ZHENGHE electronics Co., Ltd, Jining 272023 (China)

    2014-04-01

    Highlights: • Macromolecular materials were chosen to modify thermosetting polyimide (TSPI). • The formation of IPN structure in TSPI composite polymers was discussed. • The special mechanical properties required were the main study object. • The desired candidate materials should have proper hardness and toughness. • The specific mechanical data are quantitatively determined by experiments. - Abstract: 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.

  3. Digital Divide between Teachers and Students in Urban Bangladesh

    DEFF Research Database (Denmark)

    Khalid, Md. Saifuddin

    2011-01-01

    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.

  4. Operation of a bidirectional voltage-dividing bremsstrahlung diode

    Science.gov (United States)

    Harper-Slaboszewicz, V. J.; Lee, J. R.; Hedemann, M. A.; Baldwin, G. T.; Poukey, J. W.; Lorence, L. J., Jr.; Carlson, G. A.; Fowler, W. E.; Faucett, D. L.; Landron, C. O.

    1990-04-01

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

  5. Operation of a bidirectional voltage-dividing bremsstrahlung diode

    International Nuclear Information System (INIS)

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

  6. Dividing Discipline : Structures of Communication in International Relations

    DEFF Research Database (Denmark)

    Kristensen, Peter Marcus

    2012-01-01

    International Relations (IR) has cultivated an image as a discipline with strong divisions along paradigmatic, methodological, metatheoretical, geographical, and other lines. This article questions that image analyzing the latent structures of communication in IR. It uses citation data from more than 20,000 articles published in 59 IR journals to construct a network among IR journals and finds a discipline with a center consisting of pedigreed IR journals, albeit closely related to political science. Divisions are identifiable as specialty areas that form clusters of specialized journals along the periphery of the network—security studies and international political economy in particular—but communication is also divided along the lines of geography and policy/theory. The article concludes that divisions notwithstanding, IR communication remains centered around American, general, and theoretical IR journals and that to practice this particular kind of communication is an important dimension of being an IR scholar.

  7. Amniotic membrane graft to reconstruct divided nevi of eyelids.

    Science.gov (United States)

    Bhattacharjee, Kasturi; Singh, Manpreet; Bhattacharjee, Harsha

    2015-01-01

    Two patients with congenital divided nevi of the eyelids presented with chief symptoms of cosmetic blemish (n=2) and epiphora (n=1). All the lesions were surgically excised with histological free margins and amniotic membrane graft (AMG) was used to cover the mucosal and eyelid marginal defects. Caruncular and punctal involvement was managed with complete excision and monocanalicular stent insertion to prevent punctal stenosis. AMG provided an adequate scaffold for conjunctival regenesis and anatomic continuity was found within 6?weeks in both patients. None of them had any residual pigmentation or disease recurrence after a follow-up of more than 2.5?years. Local absence of eyelashes was the only drawback which patients masked with modern artificial eyelashes or make-up. This novel utility of AMG illustrates effective conjunctival regenesis and maintenance of mucocutaneous junction functionality. PMID:26009598

  8. 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)

  9. Proliferating parasites in dividing cells Kimmel's branching model revisited

    CERN Document Server

    Bansaye, V

    2007-01-01

    We consider a branching model introduced by M. Kimmel for cell division with parasite infection. Cells contain proliferating parasites which are shared randomly between the two daughter cells when they divide. We determine the probability that the organism recovers, meaning that the asymptotic proprotion of contaminated cells vanishes. We study the tree of contaminated cells, give the asymptotic number of contaminated cells and the asymptotic proportions of contaminated cells with a given number of parasites. This depends on domains inherited from the behavior of branching processes in random environment (BPRE) and given by the bivariate value of the means of parasite offsprings. In one of these domains, the convergence of proportions holds in probability, the limit is deterministic and given by the Yaglom quasistationary distribution. Moreover we get an interpretation of the limit of the Q-process as the size-biased quasistationary distribution.

  10. Divide et Impera?: Western Engagement in the Middle East

    Directory of Open Access Journals (Sweden)

    Marek ?ejka

    2012-12-01

    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.

  11. Universal Service in a Broader Perspective: The European Digital Divide

    Directory of Open Access Journals (Sweden)

    Maria Concepcion GARCIA-JIMENEZ

    2009-01-01

    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.

  12. Divided-pulse nonlinear amplification and simultaneous compression

    Science.gov (United States)

    Hao, Qiang; Zhang, Qingshan; Sun, Tingting; Chen, Jie; Guo, Zhanhua; Wang, Yuqing; Guo, Zhengru; Yang, Kangwen; Zeng, Heping

    2015-03-01

    We report on a fiber laser system delivering 122 fs pulse duration and 600 mW average power at 1560 nm by the interplay between divided pulse amplification and nonlinear pulse compression. A small-core double-clad erbium-doped fiber with anomalous dispersion carries out the pulse amplification and simultaneously compresses the laser pulses such that a separate compressor is no longer necessary. A numeric simulation reveals the existence of an optimum fiber length for producing transform-limited pulses. Furthermore, frequency doubling to 780 nm with 240 mW average power and 98 fs pulse duration is achieved by using a periodically poled lithium niobate crystal at room temperature.

  13. Divide and be different: priestly identity in the Persian period

    Scientific Electronic Library Online (English)

    Esias E., Meyer.

    Full Text Available The article focused on the Hebrew root -•” [divide] [bdl] in Priestly and post-Priestly material of the Pentateuch. In Genesis 1 God is the subject of the verb and often enough in the Holiness Code, but in many instances in Leviticus (e.g. 10:10 and 11:47) it is expected of priests to perform the sa [...] me act. It was argued that in this regard priests were to imitate God. The article further argued that these texts helped us to describe Jewish identity in the Persian period as an identity of non-conformity, and they also helped us to describe the priests' own understanding of their role in maintaining this identity.

  14. How Visibility and Divided Attention Constrain Social Contagion

    CERN Document Server

    Hodas, Nathan Oken

    2012-01-01

    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...

  15. Flagellation of Pseudomonas aeruginosa in newly divided cells

    Science.gov (United States)

    Zhao, Kun; Lee, Calvin; Anda, Jaime; Wong, Gerard

    2015-03-01

    For monotrichous bacteria, Pseudomonas aeruginosa, after cell division, one daughter cell inherits the old flagellum from its mother cell, and the other grows a new flagellum during or after cell division. It had been shown that the new flagellum grows at the distal pole of the dividing cell when the two daughter cells haven't completely separated. However, for those daughter cells who grow new flagella after division, it still remains unknown at which pole the new flagellum will grow. Here, by combining our newly developed bacteria family tree tracking techniques with genetic manipulation method, we showed that for the daughter cell who did not inherit the old flagellum, a new flagellum has about 90% chances to grow at the newly formed pole. We proposed a model for flagellation of P. aeruginosa.

  16. Spike sorting for polytrodes: a divide and conquer approach

    Directory of Open Access Journals (Sweden)

    Nicholas V. Swindale

    2014-02-01

    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.

  17. 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

  18. Asteroid Lightcurve Photometry at the Palmer Divide Observatory

    Science.gov (United States)

    Warner, Brian D.; Harris, A. W.

    2007-05-01

    The concentrated program on asteroid lightcurves at the Palmer Divide Observatory has produced more than 300 results published in the Minor Planet Bulletin, Icarus, Nature, and other publications. The Hungaria asteroids have received particular attention the past three years, with 81 lightcurves published. The Hungarias provide a unique opportunity to compare the characteristics of non planet-crossing inner main-belt asteroids against those of the NEA population. The results so far indicate a similarity in the distribution of rotation rates, with an excess of both slow and fast rotators, as well as binary population (5 Hungaria binaries have been discovered at PDO). This suggests that both spin rate evolution and binary formation are not closely related to tidal interactions with major planets, but instead are likely the result of processes present in both main-belt and planet-crossing populations. A recently implemented and concurrent program will determine the absolute magnitudes (H/G) and V-R color index for a large number of brighter main-belt and near-Earth Asteroids. The motivation for this is the fact that current asteroid surveys obtain only very crude magnitudes of the objects discovered, so the greatest uncertainty in size frequency distribution of asteroids, and NEAs in particular, is in the determination of absolute magnitudes. The extended goal is to do statistical studies relating taxonomic class, phase, and other characteristics to lightcurve periods and amplitudes. Work at the Palmer Divide Observatory is funded by NSF grant AST-0607505 and NASA grants NNX 06AB30G and NNG 06GI32G. The H/G project is funded in part by a Gene Shoemaker NEO Grant from the Planetary Society.

  19. Platonic Relationships among Resistors

    Science.gov (United States)

    Allen, Bradley; Liu, Tongtian

    2015-01-01

    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. Furthermore, several authors have used advanced…

  20. Platonic Relationships Among Resistors

    Science.gov (United States)

    Allen, Bradley; Liu, Tongtian

    2015-02-01

    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.

  1. BRIDGING THE KNOWLEDGE DIVIDE Educational Technology for Development

    Directory of Open Access Journals (Sweden)

    Reviewed by Ozlem OZAN,

    2009-10-01

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

  2. Divide, conquer and coordinate: globally coordinated switching linear dynamical system.

    Science.gov (United States)

    Li, Rui; Tian, Tai-Peng; Sclaroff, Stan

    2012-04-01

    The goal of this work is to learn a parsimonious and informative representation for high-dimensional time series. Conceptually, this comprises two distinct yet tightly coupled tasks: learning a low-dimensional manifold and modeling the dynamical process. These two tasks have a complementary relationship as the temporal constraints provide valuable neighborhood information for dimensionality reduction and, conversely, the low-dimensional space allows dynamics to be learned efficiently. Solving these two tasks simultaneously allows important information to be exchanged mutually. If nonlinear models are required to capture the rich complexity of time series, then the learning problem becomes harder as the nonlinearities in both tasks are coupled. A divide, conquer, and coordinate method is proposed. The solution approximates the nonlinear manifold and dynamics using simple piecewise linear models. The interactions and coordinations among the linear models are captured in a graphical model. The model structure setup and parameter learning are done using a variational Bayesian approach, which enables automatic Bayesian model structure selection, hence solving the problem of overfitting. By exploiting the model structure, efficient inference and learning algorithms are obtained without oversimplifying the model of the underlying dynamical process. Evaluation of the proposed framework with competing approaches is conducted in three sets of experiments: dimensionality reduction and reconstruction using synthetic time series, video synthesis using a dynamic texture database, and human motion synthesis, classification, and tracking on a benchmark data set. In all experiments, the proposed approach provides superior performance. PMID:21808088

  3. 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)

  4. Informaticiens Sans Frontieres: Helping to bridge the Digital Divide

    CERN Document Server

    CERN. Geneva

    2009-01-01

    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...

  5. Reduced Complexity Divide and Conquer Algorithm for Large Scale TSPs

    Directory of Open Access Journals (Sweden)

    Hoda A. Darwish

    2014-01-01

    Full Text Available The Traveling Salesman Problem (TSP is the problem of finding the shortest path passing through all given cities while only passing by each city once and finishing at the same starting city. This problem has NP-hard complexity making it extremely impractical to get the most optimal path even for problems as small as 20 cities since the number of permutations becomes too high. Many heuristic methods have been devised to reach “good” solutions in reasonable time. In this paper, we present the idea of utilizing a spatial “geographical” Divide and Conquer technique in conjunction with heuristic TSP algorithms specifically the Nearest Neighbor 2-opt algorithm. We have found that the proposed algorithm has lower complexity than algorithms published in the literature. This comes at a lower accuracy expense of around 9%. It is our belief that the presented approach will be welcomed to the community especially for large problems where a reasonable solution could be reached in a fraction of the time.

  6. Cell survival assays in a slowly dividing normal tissue

    International Nuclear Information System (INIS)

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

  7. Crossing the Digital Divide: Connecting GIS, Time Series and Space-Time Arrays (Invited)

    Science.gov (United States)

    Maidment, D. R.; Salas, F.; Domenico, B.; Nativi, S.

    2010-12-01

    Hydrologic information science requires several different kinds of information: GIS coverages of water features of the land surface and subsurface; time series of observations of streamflow, water quality, groundwater levels and climate; and space-time arrays of weather, climate and remotely sensed information. Increasingly, such information is being published as web services, in standardized data structures that transmit smoothly through the internet. A large "Digital Divide" exists between the world of discrete spatial objects in GIS and associated time series, and the world of continuous space-time arrays as is used weather and climate science. In order to cross this divide, it should be possible to search for quantities such as “precipitation” and to find the information no matter whether it comprises time series of precipitation at gage sites, or space-time arrays of precipitation from Nexrad radar rainfall measurements. This means that servers of discrete space-time hydrologic data, such as the CUAHSI HydroServer, and servers of continuous space-time weather and climate data, such as the Unidata THREDDS server, should be able to be indexed in a unified manner that will permit discovery of common information types across different classes of information services. This paper will explore options for accomplishing this goal using the CUAHSI HydroServer and the Unidata THREDDS server as representative examples of information service providers. Among the options to be explored is GI-cat, a federated, standards-based catalog service developed at the Earth and Space Science Informatics Laboratory of the University of Florence.

  8. HIV-1 latency in actively dividing human T cell lines

    Directory of Open Access Journals (Sweden)

    Berkhout Ben

    2008-04-01

    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.

  9. A Divide-and-Conquer Approach to Commercial Territory Design / Procedimiento divide y vencerás para el diseño de territorios comerciales

    Scientific Electronic Library Online (English)

    M. Angélica, Salazar-Aguilar; J. Luis, González-Velarde; Roger Z., Ríos-Mercado.

    2012-09-01

    Full Text Available En este trabajo se presenta un procedimiento heurístico para el diseño de territorios comerciales. El procedimiento propuesto, basado en el paradigma dividir-y-vencer, consiste básicamente en un proceso de dicotomías sucesivas a partir de una instancia dada. Durante este proceso se resuelven una ser [...] ie de subproblemas de programación cuadrática entera. Los resultados computacionales muestran que la heurística propuesta es una técnica de solución atractiva que permite la obtención de soluciones óptimas locales para instancias grandes del problema, las cuales resultan intratables al intentar resolverlas a través de métodos exactos. Abstract in english A new heuristic procedure for a commercial territory design problem is introduced in this work. The proposed procedure is based on the divide-and-conquer paradigm and basically consists of a successive dichotomy process on a given large instance of the problem. During this process, a series of integ [...] er quadratic subproblems is solved. The obtained computational results have shown that the proposed heuristic is an attractive technique for obtaining locally optimal solutions for large instances which are intractable by using exact optimization methods.

  10. 76 FR 55643 - Helena National Forest; Montana; Divide Travel Plan EIS

    Science.gov (United States)

    2011-09-08

    ...DEPARTMENT OF AGRICULTURE Forest Service Helena National Forest; Montana; Divide Travel Plan EIS AGENCY: Forest Service...written comments to the Helena National Forest, ATTN: Divide Travel Plan; 2880 Skyway Drive,...

  11. Bridging the divide between genomic science and indigenous peoples.

    Science.gov (United States)

    Jacobs, Bette; Roffenbender, Jason; Collmann, Jeff; Cherry, Kate; Bitsói, LeManuel Lee; Bassett, Kim; Evans, Charles H

    2010-01-01

    The new science of genomics endeavors to chart the genomes of individuals around the world, with the dual goals of understanding the role genetic factors play in human health and solving problems of disease and disability. From the perspective of indigenous peoples and developing countries, the promises and perils of genomic science appear against a backdrop of global health disparity and political vulnerability. These conditions pose a dilemma for many communities when attempting to decide about participating in genomic research or any other biomedical research. Genomic research offers the possibility of improved technologies for managing the acute and chronic diseases that plague their members. Yet, the history of particularly biomedical research among people in indigenous and developing nations offers salient examples of unethical practice, misuse of data, and failed promises. This dilemma creates risks for communities who decide either to participate or not to participate in genomic science research. Some argue that the history of poor scientific practice justifies refusal to join genomic research projects. Others argue that disease poses such great threats to the well-being of people in indigenous communities and developing nations that not participating in genomic research risks irrevocable harm. Thus, some communities particularly among indigenous peoples have declined to participate as subjects in genomic research. At the same time, some communities have begun developing new guidelines, procedures, and practices for engaging with the scientific community that offer opportunities to bridge the gap between genomic science and indigenous and/or developing communities. Four new approaches warrant special attention and further support: consulting with local communities; negotiating the complexities of consent; training members of local communities in science and health care; and training scientists to work with indigenous communities. Implicit is a new definition of "rigorous scientific research," one that includes both community development and scientific progress as legitimate objectives of genomic research. Innovative translational research is needed to develop practical, mutually acceptable methods for crossing the divide between genomic researchers and indigenous communities. This may mean the difference between success and failure in genomic science, and in improving health for all peoples. PMID:20880250

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

    Science.gov (United States)

    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

    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.

  13. 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

  14. Water Wisdom: 23 Stand-Alone Activities on Water Supply and Water Conservation for High School Students. 2nd Edition.

    Science.gov (United States)

    Massachusetts State Water Resources Authority, Boston.

    This water conservation education program for high schools consists of both stand-alone activities and teacher support materials. Lessons are divided into six broad categories: (1) The Water Cycle; (2) Water and Society; (3) Keeping Water Pure; (4) Visualizing Volumes; (5) The Economics of Water Use; and (6) Domestic Water Conservation. The…

  15. Microstructure and temperature coefficient of resistance of thin cermet resistor films deposited from CrSi2-Cr-SiC targets by S-gun magnetron

    International Nuclear Information System (INIS)

    Technological solutions for producing nanoscale cermet resistor films with sheet resistances above 1000 ?/? and low temperature coefficients of resistance (TCR) have been investigated. 2-40 nm thick cermet films were sputter deposited from CrSi2-Cr-SiC targets by a dual cathode dc S-gun magnetron. In addition to studying film resistance versus temperature, the nanofilm structural features and composition were analyzed using scanning electron microscopy, atomic force microscopy, high-resolution transmission electron microscopy, energy-dispersive x-ray spectroscopy, and electron energy loss spectroscopy. This study has revealed that all cermet resistor films deposited at ambient and elevated temperatures were amorphous. The atomic ratio of Si to Cr in these films was about 2 to 1. The film TCR displayed a significant increase when the deposited film thickness was reduced below 2.5 nm. An optimized sputter process consisting of wafer degassing, cermet film deposition at elevated temperature with rf substrate bias, and a double annealing in vacuum, consisting of in situ annealing following the film sputtering and an additional annealing following the exposure of the wafers to air, has been found to be very effective for the film thermal stabilization and for fine tuning the film TCR. Cermet films with thicknesses in the range of 2.5-4 nm deposited using this technique had sheet resistances ranging from 1800 to 1200 ?/? and TCR values from -50 ppm/ deg. C and TCR values from -50 ppm/ deg. C to near zero, respectively. A possible mechanism responsible for the high efficiency of annealing the cermet films in vacuum (after preliminary exposure to air), resulting in resistance stabilization and TCR reduction, is also discussed.

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

    International Nuclear Information System (INIS)

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

  17. Zones of silence: A framework beyond the digital divide (originally published in May 2006)

    OpenAIRE

    Potter, Amelia Bryne

    2007-01-01

    There is no doubt that much digital divide work — including connectivity initiatives, technology transfer programs, and other projects — is done with good intention. Yet, as has been widely recognized, the conceptual framework of the digital divide is limiting. The language of the digital divide not only places people into simplistic “have”/“have not” categories, making assumptions about the solution to “information poverty” with little attention to local contexts, its logic a...

  18. Combination N-Way Power Divider/Combiner and Noninvasive Reflected Power Detection

    National Oceanic and Atmospheric Administration, Department of Commerce — An N-way RF/microwave power divider/combiner utilizes one input and N outputs, or conversely N inputs and one output to divide (or combine) RF/microwave power while...

  19. Marketing mix of chosen Slovak mineral water

    OpenAIRE

    Juhanová Silvia; Tometz Ladislav

    2001-01-01

    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...

  20. Divided Plato

    International Nuclear Information System (INIS)

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

  1. Development of a one-chip quantized Hall resistance voltage divider

    International Nuclear Information System (INIS)

    A resistive voltage divider, which is constructed from a binary segmented series array of quantized Hall resistance (QHR) bars fabricated on one chip, named the ‘QHR voltage divider’, has been developed. The QHR voltage divider does not, in principle, require time-consuming bootstrap self-calibration and will provide voltage ratios that are defined by fundamental physical constants with small uncertainties. To evaluate the performance of the QHR voltage divider, the dependence of the Hall resistances RH of all serial segments on the magnetic flux density was measured. The results of the RH measurement showed large and well-defined plateaus, and it was confirmed that the fabricated QHR divider in conjunction with a suitable voltage source would function as a voltage divider. From a preliminary test of the voltage ratios of the QHR voltage divider, deviations from nominal ratios were measured to be less than 1.4 × 10?6, and the expanded uncertainty of the measurement was estimated to be less than 4.1 × 10?6. (paper)

  2. Automatic calibration of inductive voltage dividers for the NASA Zeno experiment

    Science.gov (United States)

    Avramov, Svetlana; Oldham, Nile M.

    1993-01-01

    Two inductive voltage dividers (IVDs) used for temperature measurements in NASA's Zeno experiment were tested. In order to obtain the required resolution of 10 parts per billion, a 30-bit binary inductive voltage divider developed at the National Institute of Standards and Technology was used to measure the differential linearity of the Zeno IVDs. Automatic measurements were performed on the dividers in the Zeno engineering model at frequencies of 266 and 351 Hz over a ratio range of 0.55-0.56. The measured differential linearity limits the temperature resolution to 5/micro-K.

  3. Effect of Pulse and dc Formation on the Performance of One-Transistor and One-Resistor Resistance Random Access Memory Devices

    Science.gov (United States)

    Liu, Hong-Tao; Yang, Bao-He; Lv, Hang-Bing; Xu, Xiao-Xin; Luo, Qing; Wang, Guo-Ming; Zhang, Mei-Yun; Long, Shi-Bing; Liu, Qi; Liu, Ming

    2015-02-01

    We investigate the effect of the formation process under pulse and dc modes on the performance of one transistor and one resistor (1T1R) resistance random access memory (RRAM) device. All the devices are operated under the same test conditions, except for the initial formation process with different modes. Based on the statistical results, the high resistance state (HRS) under the dc forming mode shows a lower value with better distribution compared with that under the pulse mode. One of the possible reasons for such a phenomenon originates from different properties of conductive filament (CF) formed in the resistive switching layer under two different modes. For the dc forming mode, the formed filament is thought to be continuous, which is hard to be ruptured, resulting in a lower HRS. However, in the case of pulse forming, the filament is discontinuous where the transport mechanism is governed by hopping. The low resistance state (LRS) can be easily changed by removing a few trapping states from the conducting path. Hence, a higher HRS is thus observed. However, the HRS resistance is highly dependent on the length of the gap opened. A slight variation of the gap length will cause wide dispersion of resistance.

  4. Water watch

    International Nuclear Information System (INIS)

    This issue of open-quotes Water Watchclose quotes focuses on summer streamflow. In addition, a summary of streamflow, soil moisture, and water supply conditions through the end of May is presented. In addition, short-term streamflow forecasts are given. Forecasts are based on the National Weather Service US Climate Analysis Center's 90-day outlook. Temperature and precipitation probability estimates given in the outlook are based primarily on the average of monthly forecasts since 1974 and seasonal forecasts since 1959 at 100 US weather reporting stations. Regional analyses are based on reports and data provided by the National Weather Service Office of Hydrology and River Forecast Centers, the US Department of Agriculture, the Bureau of Reclamation, the Soil Conservation Service, the California Department of Water Resources, and the US Geological Survey. For purposes of reporting, the US is divided into six regions. The data presented can be used to observe how weather conditions affect hydro generation in April

  5. Crossing the phantom divide line in the Holographic dark energy model in a closed universe

    OpenAIRE

    Sadjadi, H. Mohseni

    2009-01-01

    Conditions needed to cross the phantom divide line in an interacting holographic dark energy model in closed Friedmann- Robertson-Walker universe are discussed. The probable relationship between this crossing and the coincidence problem is studied.

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

    Directory of Open Access Journals (Sweden)

    Paul Chambers

    2010-04-01

    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.

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

    Science.gov (United States)

    Serres, Nicolas (Epinal, FR)

    2010-11-09

    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.

  8. Statistical and numerical methods to improve the transient divided bar method

    DEFF Research Database (Denmark)

    Bording, Thue Sylvester; Nielsen, S.B.

    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.

  9. Divided Government, Legislative Productivity, and Policy Change in the USA and France

    OpenAIRE

    Baumgartner, Frank; Brouard, Sylvain; Grossman, Emiliano; Lazardeux, Sébastien; Moody, Jonathan

    2013-01-01

    The concept of “divided government” is more complicated than scholars have allowed. In the USA, truly unified government, where the president enjoys a filibuster-proof majority in the Senate as well as a majority in the House, is rare. In France, truly unified government has been more common, but divided government has also occurred several times. Democratic governance requires that parties address important issues and they do so regardless of the patterns of institutional control. Nevert...

  10. Are egalitarians really vulnerable to the Levelling-Down Objection and the Divided World Example?

    OpenAIRE

    Subramanian, S.

    2011-01-01

    This essay is a quick critique of one aspect of Derek Parfit’s criticism of Egalitarianism in his larger consideration of the claims of, and distinction between, Prioritarianism and Egalitarianism. It reviews issues relating to the ‘Levelling Down Objection’ and the ‘Divided World Example’. More specifically, it is argued that the Levelling Down Objection is a serious problem only for Pure Telic Egalitarianism, not for Pluralist Telic Egalitarianism; and thateven in a Divided World...

  11. The robotics divide a new frontier in the 21st century?

    CERN Document Server

    López Peláez, Antonio

    2013-01-01

    Analyzes how robotics will shape our societies in the twenty-first century; a time when industrial and service robotics, particularly for military and aerospace purposes, will become an essential technology Examines an emerging divide: the "robotics divide"; a phenomenon linked to the model to integrate advanced robotics in economic, social and military spheres Focuses on the main technological trends in the field of robotics, and the impact that robotics will have on different facets of social life

  12. How to Overcome the Digital Divide? The Determinants of Internet Diffusion

    OpenAIRE

    Shchetinin, Oleg; Baptiste, Massenot

    2008-01-01

    We document the existence and the persistence of the digital divide and investigate the determinants of the Internet diffusion in both developing and developed countries. Our study innovates on the following: i) we use a data set that covers more countries and years than the earlier studies ii) We use the GMM estimator which requires milder assumptions to be consistent than the traditionally used panel data estimators in technology diffusion studies. We find that i) the digital divide is ...

  13. Online but still divided: Inequality in private internet use in Germany

    OpenAIRE

    Coneus, Katja; Schleife, Katrin

    2010-01-01

    In this analysis, we compare the determinants of the first-level and the second-level digital divide for private internet use in Germany. Our work offers three important innovations. First, we use the exact weekly duration of internet use to explain inequalities in internet intensity, explicitly controlling for non-users. Secondly, we use the frequencies of five different internet applications to further investigate the determinants of the second-level digital divide. Thirdly, we estimate sel...

  14. Probabilistic divide-and-conquer: a new exact simulation method, with integer partitions as an example

    OpenAIRE

    Arratia, Richard; DeSalvo, Stephen

    2011-01-01

    We propose a new method, probabilistic divide-and-conquer, for improving the success probability in rejection sampling. For the example of integer partitions, there is an ideal recursive scheme which improves the rejection cost from asymptotically order $n^{3/4}$ to a constant. We show other examples for which a non--recursive, one--time application of probabilistic divide-and-conquer removes a substantial fraction of the rejection sampling cost. We also present a varia...

  15. The Effect of Divided Attention on Emotion-Induced Memory Narrowing

    OpenAIRE

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

    2013-01-01

    Individuals are more likely to remember emotional than neutral information, but this benefit does not always extend to the surrounding background information. This memory narrowing is theorized to be linked to the availability of attentional resources at encoding. In contrast to the predictions of this theoretical account, altering participants’ attentional resources at encoding, by dividing attention, did not affect the emotion-induced memory narrowing. Attention was divided using three se...

  16. Analyze the Performance of Divide and Conquer Scheme for Wireless Sensor Network?

    Directory of Open Access Journals (Sweden)

    Gagandeep Kaur Kaleka

    2014-12-01

    Full Text Available Wireless sensor network (WSN is a network of small light weight wireless nodes which are highly distributed and deployed in large numbers. There are some issues in wsn like scalability, deployment, energy consumption and many more. There are also many energy efficient techniques in wireless sensor network like LEACH, HEAP etc. Divide and conquer is also one of the efficient technique which is based upon manually deployment. In this paper, divide and conquer scheme is explained in detail.

  17. Exergy loss analysis of heat transfer across the wall of the dividing-wall distillation column

    International Nuclear Information System (INIS)

    The dividing-wall distillation column is thermodynamically equivalent to the Petlyuk column on the condition that no heat transfer is allowed across the dividing wall. However, better energy efficiency of the column may be obtained if heat transfer occurs within a certain part of the wall. The effects of heat transfer across the dividing wall can be analyzed by using the column grand composite curve (CGCC). The heat transfer potential across the wall can be observed by looking at the CGCC of both column sections alongside the dividing wall. However, the possibility of whether heat should be added or rejected at any stage is not clearly known ahead of the CGCC. Consequently, in this work, the exergy analysis is applied to the dividing-wall column in order to determine whether heat should be added or rejected at any particular stage. Also, the minimum exergy loss value in the column is set as the criterion for determining the heat load targets at any stage. These load targets can then be plotted as a T-H profile similar to the CGCC. This methodology was reported to successfully apply to the column with multiple feeds and products. After having identified the locations and quantities of the feasible heat transfer across the dividing wall, the benefits are discussed via three case studies

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

    Directory of Open Access Journals (Sweden)

    Vashishta P.

    2011-05-01

    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

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

    Science.gov (United States)

    Shimojo, F.; Ohmura, S.; Nakano, A.; Kalia, R. K.; Vashishta, P.

    2011-05-01

    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

  20. Kinematic Identification of Parallel Mechanisms by a Divide and Conquer Strategy

    DEFF Research Database (Denmark)

    Durango, Sebastian; Restrepo, David

    2010-01-01

    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.

  1. Neural mechanisms of human perceptual choice under focused and divided attention.

    Science.gov (United States)

    Wyart, Valentin; Myers, Nicholas E; Summerfield, Christopher

    2015-02-25

    Perceptual decisions occur after the evaluation and integration of momentary sensory inputs, and dividing attention between spatially disparate sources of information impairs decision performance. However, it remains unknown whether dividing attention degrades the precision of sensory signals, precludes their conversion into decision signals, or dampens the integration of decision information toward an appropriate response. Here we recorded human electroencephalographic (EEG) activity while participants categorized one of two simultaneous and independent streams of visual gratings according to their average tilt. By analyzing trial-by-trial correlations between EEG activity and the information offered by each sample, we obtained converging behavioral and neural evidence that dividing attention between left and right visual fields does not dampen the encoding of sensory or decision information. Under divided attention, momentary decision information from both visual streams was encoded in slow parietal signals without interference but was lost downstream during their integration as reflected in motor mu- and beta-band (10-30 Hz) signals, resulting in a "leaky" accumulation process that conferred greater behavioral influence to more recent samples. By contrast, sensory inputs that were explicitly cued as irrelevant were not converted into decision signals. These findings reveal that a late cognitive bottleneck on information integration limits decision performance under divided attention, and places new capacity constraints on decision-theoretic models of information integration under cognitive load. PMID:25716848

  2. Are egalitarians really vulnerable to the Levelling-Down Objection and the Divided World Example?

    Directory of Open Access Journals (Sweden)

    S. Subramanian

    2011-05-01

    Full Text Available This essay is a quick critique of one aspect of Derek Parfit’s criticism of Egalitarianism in his larger consideration of the claims of, and distinction between, Prioritarianism and Egalitarianism. It reviews issues relating to the ‘Levelling Down Objection’ and the ‘Divided World Example’. More specifically, it is argued that the Levelling Down Objection is a serious problem only for Pure Telic Egalitarianism, not for Pluralist Telic Egalitarianism; and thateven in a Divided World, one can have an egalitarian justification forpreferring an equal distribution of a smaller sum of wellbeing to an unequal distribution of a larger sum. By these means, it is contended that Parfit’s claim of the vulnerability of Egalitarianism to the Levelling Down Objection and the Divided World Example is not sustainable

  3. Divided naevus of the penis: two paediatric cases with dermoscopic findings.

    Science.gov (United States)

    Mendes, C P; Samorano, L P; Alessi, S S; Nico, M M S

    2014-08-01

    Divided or kissing naevi are located on adjacent parts of the body that are separated during embryogenesis. Divided naevus of the penis (DNP) is exceedingly rare, with < 15 cases reported in the English language literature. Divided penile naevi affect the glans penis and inner foreskin, which are anatomical structures believed to have a common embryological origin. We report the clinical, dermoscopic and histopathological findings of two children with DNP. To our knowledge, this is the first report of patients with DNP seen in South America, and the first in which dermoscopic findings are discussed; these included a large globular pattern in one patient, and homogeneous, streaked and globular patterns in the other. PMID:24985200

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

    OpenAIRE

    Roland Füss; Bechtel, Michael M.

    2008-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Vahab Dehlaghi

    2007-01-01

    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.

  6. 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

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

    OpenAIRE

    Livingstone, Sonia; Helsper, Ellen

    2007-01-01

    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...

  8. Divided Identity: Part-Time Faculty in Public Colleges and Universities

    Science.gov (United States)

    Levin, John S.; Montero Hernandez, Virginia

    2014-01-01

    This article addresses the identity claims of part-time faculty at three types of higher education institutions. Using culture theory and professional identity theory, the article documents that part-time faculty members across institutions have a divided sense of identity. On the one hand, they perceive themselves as professionals based on their…

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

    OpenAIRE

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

    2012-01-01

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

  10. Transcending the Divide: Where College and Secondary Reading and Study Research Coincide

    Science.gov (United States)

    Flippo, Rona F.

    2011-01-01

    Those who teach literacy usually accept the idea that reading, writing, and study strategies are developmental. Youngsters develop their literacy from birth on, and, to some teachers, dividing literacy education into steadfast designations such as early childhood, elementary, middle, secondary, and college learning (which may have pragmatic value)…

  11. Sociological implications of scientific publishing: Open access, science, society, democracy and the digital divide

    OpenAIRE

    Herb, Ulrich

    2010-01-01

    Claims for open access are mostly underpinned with 1. science—related arguments (open access accelerates scientific communication); 2. financial arguments (open access relieves the serials crisis); 3. social arguments (open access reduces the digital divide); 4. democracy—related arguments (open access facilitates participation); and, 5. socio—political arguments (open access levels disparities). Using sociological concepts and notions, this article fo...

  12. Explaining the Global Digital Divide: Economic, Political and Sociological Drivers of Cross-National Internet Use

    Science.gov (United States)

    Guillen, Mauro F.; Suarez, Sandra L.

    2005-01-01

    We argue that the global digital divide, as measured by cross-national differences in Internet use, is the result of the economic, regulatory and sociopolitical characteristics of countries and their evolution over time. We predict Internet use to increase with world-system status, privatization and competition in the telecommunications sector,…

  13. The use of the Internet in Morocco: Test for measuring the second digital divide

    Directory of Open Access Journals (Sweden)

    Samira Oukarfi

    2013-02-01

    Full Text Available This article proposes to prove economically the existence of a second level digital divide in Morocco. We have well designed and administered a questionnaire to approach 1030 persons living in the two largest cities of the Kingdom: Rabat and Casablanca. It seemed to us at the appropriate time to get down working in these big cities where normally there should not be any digital divide, at least the one of first degree, in order to detect inequalities in the use of the Internet. By the present field work we seek to determine far beyond Internet access, a kind of persons being behind the second degree digital divide. Our results lead us to say that the use of the Internet in the cities is influenced by socioeconomic position and the living conditions of individuals. The second degree digital divide is omnipresent. These results are enough to put into perspective the effectiveness of policies to ensure a wide coverage of the country by the ICT expected to create the added value and improve the living standards and social wellbeing of citizens.

  14. Nuclear Technology. Course 27: Metrology. Module 27-2, Fixed Gages, Dividers, Calipers, and Micrometers.

    Science.gov (United States)

    Selleck, Ben; Espy, John

    This second in a series of eight modules for a course titled Metrology dscribes fixed gages, dividers, calipers, vernier and dial calipers, and micrometers. The module follows a typical format that includes the following sections: (l) introduction, (2) module prerequisites, (3) objectives, (4) notes to instructor/student, (5) subject matter, (6)…

  15. Two Aspects of the Rural-Urban Divide and Educational Stratification in China: A Trajectory Analysis

    Science.gov (United States)

    Hao, Lingxin; Hu, Alfred; Lo, Jamie

    2014-01-01

    Contextualized in China's social change of the past half-century, this article conceptualizes the two aspects of China's rural-urban divide in educational inequality--the household registration system ("hukou") assigns people to a hierarchy, and the rural-urban schooling system institutionalizes unequal resource distribution…

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

    Science.gov (United States)

    Unnever, James D.; Cullen, Francis T.

    2007-01-01

    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…

  17. Crossing the Divide: Helen Keller and Yvonne Pitrois Dialogue on Diversity

    Science.gov (United States)

    Hartig, Rachel

    2007-01-01

    How do those who are living with a difference most effectively cross the cultural divide and explain themselves to mainstream society? This is a central question raised by Yvonne Pitrois in her biography of Helen Keller, titled "Une nuit rayonnante: Helen Keller" [A Shining Night: Helen Keller]. Helen Keller responded to Pitrois' book in a…

  18. Overcoming the Digital Divide: The Story of an Urban Middle School

    Science.gov (United States)

    Banister, Savilla; Fischer, John

    2010-01-01

    Access to appropriate technological resources in schools has become an issue, commonly labeled the "digital divide." While the debate ensues in regards to an explicit definition for this phenomenon, research overwhelmingly demonstrates that students of marginalized populations remain on the lower end of access to and innovative use of current…

  19. Reducing the Digital Divide through ICT Adoption: Factors, Barriers, and How ICT in Schools Can Help

    Science.gov (United States)

    Tengtrakul, Pitikorn

    2013-01-01

    Through econometric analysis of data from multiple surveys, this study explores factors that affect ICT adoption and evaluates the extent to which ICT in schools affect the ICT adoption of surrounding communities, in order to provide a perspective that can help narrow the gap of digital divide. Understanding factors affecting ICT adoption may…

  20. The Indonesian Digital Library Network Is Born To Struggle with the Digital Divide.

    Science.gov (United States)

    Fahmi, Ismail

    2002-01-01

    Describes the Indonesian Digital Library Network that is designed to develop Indonesia as a knowledge-based society. Highlights include the digital divide; problems in a developing country, including Internet accessibility, bandwidth capacity, and network delays; gathering information about national assets; information infrastructure; data…

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

    Science.gov (United States)

    Unnever, James D.; Cullen, Francis T.

    2007-01-01

    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…

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

    Directory of Open Access Journals (Sweden)

    IverHakonBrevik

    2013-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-09-18

    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.

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

    OpenAIRE

    Clements, Ben

    2012-01-01

    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.

  5. Bridging the Divide with a Question and a Kaleidoscope: Designing an Enquiry in a Challenging Setting

    Science.gov (United States)

    Counsell, Christine; Foster, Rachel; Georgiou, Maria; Mavrada, Maria; Onurkan, Meltem; Partridge, Mary; Samani, Hasan

    2012-01-01

    The Association for Historical Dialogue and Research (AHDR) is a Cyprus-based organization that works to foster dialogue among history teachers and other educators across the divide in Cyprus. In one of their UN-funded projects, AHDR members worked with UK colleagues to shape a lesson sequence and resources on the Ottoman period in Cyprus. Here…

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

    Science.gov (United States)

    Trinidad, Sue

    2007-01-01

    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…

  7. The Digital Health Divide: Evaluating Online Health Information Access and Use among Older Adults

    Science.gov (United States)

    Hall, Amanda K.; Bernhardt, Jay M.; Dodd, Virginia; Vollrath, Morgan W.

    2015-01-01

    Objective: Innovations in health information technology (HIT) provide opportunities to reduce health care spending, improve quality of care, and improve health outcomes for older adults. However, concerns relating to older adults' limited access and use of HIT, including use of the Internet for health information, fuel the digital health divide…

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

    International Nuclear Information System (INIS)

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

  9. The Systematics of Relativistically Beamed Jets from Active Galaxies and the Blazar Divide

    Science.gov (United States)

    Shastri, Prajval; Gupta, Maitrayee; Jimenez-Gomez, Estrella; Madejski, Grzegorz

    2015-04-01

    We investigate the systematics of the properties of highly relativistic jets at multiple frequencies, including gamma-ray data from the Fermi telescope and MOJAVE radio imaging on parsec scales. We test the hypothesis that the blazar divide constitutes a dichotomy. We also explore possible measures of the Doppler factor for these highly Doppler-beamed active galactic nuclei. APS

  10. Cross-Quint-Bridge Resistor

    Science.gov (United States)

    Hannaman, David J.; Lieneweg, Udo; Buehler, Martin G.; Mantalas, Linda

    1991-01-01

    Integrated-circuit conductive test pattern intended to provide data on effects of design widths and design spacings upon actual widths of conductive lines. Provides for electrical measurements both on lines of unknown width and on features having known dimensions. Data from measurements on five bridges used to determine four parameters of mathematical model describing system. In principle, pattern determines effects of width and spacing and interaction between them.

  11. Nonequilibrium fluctuations in a resistor

    OpenAIRE

    Garnier, Nicolas; Ciliberto, Sergio

    2005-01-01

    In small systems where relevant energies are comparable to thermal agitation, fluctuations are of the order of average values. In systems in thermodynamical equilibrium, the variance of these fluctuations can be related to the dissipation constant in the system, exploiting the Fluctuation-Dissipation Theorem (FDT). In non-equilibrium steady systems, Fluctuations Theorems (FT) additionally describe symmetry properties of the probability density functions (PDFs) of the fluctua...

  12. 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)

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

    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. 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.

  13. 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)

    Juan Raúl Hernández Silva

    2010-01-01

    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.

  14. Ozonization manual for water and wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Masschelein, W.J. (ed.)

    1982-01-01

    This book is divided into parts discussing ozone generation, water ozonization principles, practical aspects, and ozone analysis. Critical questions in ozone practice, costs, new developments, and flow sheets are also presented.

  15. Constructing Two-Dimensional Voronoi Diagrams via Divide-and-Conquer of Envelopes in Space

    CERN Document Server

    Setter, Ophir

    2009-05-01

    We present a general framework for computing two-dimensional Voronoi diagrams of different classes of sites under various distance functions. The framework is sufficiently general to support diagrams embedded on a family of two-dimensional parametric surfaces in $R^3$. The computation of the diagrams is carried out through the construction of envelopes of surfaces in 3-space provided by CGAL (the Computational Geometry Algorithm Library). The construction of the envelopes follows a divide-and-conquer approach. A straightforward application of the divide-and-conquer approach for computing Voronoi diagrams yields algorithms that are inefficient in the worst case. We prove that through randomization the expected running time becomes near-optimal in the worst case. We show how to employ our framework to realize various types of Voronoi diagrams with different properties by providing implementations for a vast collection of commonly used Voronoi diagrams. We also show how to apply the new framework and other exist...

  16. Divide and rule: A qualitative analysis of the debriefing process in elite team sports.

    Science.gov (United States)

    Macquet, A-C; Ferrand, C; Stanton, N A

    2015-11-01

    This article aimed to gain an understanding of the process of debriefing during major competitions in elite team sports. Debrief interviews were conducted with 9 head coaches. The interview data were used to identify how head coaches divided up the tasks given to staff and team members prior to, and during the post-match debriefing. Results showed that debriefing consisted of two steps: preparation and presentation. Preparation referred to four successive tasks. Presentation to the team of players consisted of eight tasks relating to transformational and transactional styles of leadership. Coaches were shown to divide the labor within the staff and team. The data tend to support the view that in elite team sports, coaches are both transformational and transactional leaders, adapting their style of leadership to the situation, athletes and time available. This study provides insights into the task-work and team-work underlying team functioning and division of labor. PMID:26154201

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

    CERN Document Server

    Loh, Woong-Kee; Lee, Wookey

    2010-01-01

    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...

  18. Treatment of Divided Nevus of the Penis with Circumcision and Free Inner Prepuce Grafting

    Science.gov (United States)

    Li, Zhi-Bin; Liu, Tun; Zhang, Qing-Guo

    2015-01-01

    Summary: Divided nevus of the penis is exceedingly rare. Desruelles et al. reported the first divided nevus on the penis in 1998, and, since then, only 17 cases have been reported in the English language literature. This article presents the successful excision and histopathologic evaluation of the nevi. The glans was reconstructed by a full-thickness skin graft using remnant foreskin. Six months after the operation, the patient showed no deformity of the glans and no loss of sensation. The lesion on the glans can be successfully reconstructed using the remnant foreskin with satisfactory aesthetic and functional outcome. This method is desirable with minimal donor-site morbidity and inconspicuous donor-site scars.

  19. R.D. Laing and theology: the influence of Christian existentialism on "The Divided Self".

    Science.gov (United States)

    Miller, Gavin

    2009-04-01

    The radical psychiatrist R.D. Laing's first book, "The Divided Self" (1960), is informed by the work of Christian thinkers on scriptural interpretation -- an intellectual genealogy apparent in Laing's comparison of Karl Jaspers's symptomatology with the theological tradition of "form criticism." Rudolf Bultmann's theology, which was being enthusiastically promoted in 1950s Scotland, is particularly influential upon Laing. It furnishes him with the notion that schizophrenic speech expresses existential truths as if they were statements about the physical and organic world. It also provides him with a model of the schizoid position as a form of modern-day Stoicism. Such theological recontextualization of "The Divided Self" illuminates continuities in Laing's own work, and also indicates his relationship to a wider British context, such as the work of the "clinical theologian" Frank Lake. PMID:19999829

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

    Directory of Open Access Journals (Sweden)

    N.E.E. Achebe

    2013-03-01

    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.

  1. 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

  2. The cost of dividing the commons: Overlapping property systems in Tonle Sap, Cambodia

    Directory of Open Access Journals (Sweden)

    Thol Dina

    2015-03-01

    Full Text Available This paper examines the political implications of dividing the commons through the case study of private fishing lots in the Tonle Sap Great Lake of Cambodia. The de facto private property in Tonle Sap lasted for over 100 years until the government abolished the system completely in March 2012. Unlike conventional studies of the commons which assume away the question of divisibility as too costly to be realistic, we argue that divided management occurs even when the cost is very high. This “cost” is not merely economic, but also political. Our case study illustrates how this political cost is channeled through a network of influential people to maintain the resource system and how a private property on the commons can be demolished, also for political reasons.

  3. 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

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

    OpenAIRE

    Segarani Naidoo; Jaya Raju

    2012-01-01

    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 differentlevels of literacy, inf...

  5. Substrate integrated waveguide power divider, circulator and coupler in [10-15] GHz band

    OpenAIRE

    Feham, Bouchra Rahali Mohammed

    2014-01-01

    The Substrate Integrated Waveguide (SIW) technology is an attractive approach for the design of high performance microwave and millimeter wave components, as it combines the advantages of planar technology, such as low fabrication costs, with the low loss inherent to the waveguide solution. In this study, a substrate integrated waveguide power divider, circulator and coupler are conceived and optimized in [10-15] GHz band by Ansoft HFSS code. Thus, results of this modeling a...

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

    OpenAIRE

    Babeesh Kumar; Sushila Vikas Maheshkar; Ankur Singh Bist

    2014-01-01

    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 o...

  7. The Gender Digital Divide in Rural Pakistan: How Wide is it and How to Bridge it?

    OpenAIRE

    Siegmann, K. A.

    2009-01-01

    While Pakistan’s National Information Technology (IT) Policy aims at harnessing the potential of information and communication technologies (ICTs) for development, especially in the underserved rural areas, it ignores the role of existing gender inequalities on the possible benefits of ICTs. We have investigated aspects of the ‘gender digital divide’ in rural areas of Pakistan in order to enable an evidence-based gender-sensitive revision of the policy as well as ICT-related interventio...

  8. A Countryside Perspective of Queer : - queering the city/countryside divide

    OpenAIRE

    Gagnesjo?, Sara

    2014-01-01

    This thesis contributes with a countryside perspective to queer research by highlighting the countryside as a context where queer lives are lived. In the thesis I problematize the city/countryside divide with a view of the concept of queer as dependent on space and time.  The empirical materials are generated through a workshop on queerness, gathering people living within a countryside context; the materials consist of a discussion and written responses to questions on queerness and the city...

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

    DEFF Research Database (Denmark)

    Petersen, Hanne

    2012-01-01

    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.

  10. Characteristics of Optimal Function for Ontology Similarity Measure via Multi-dividing

    OpenAIRE

    Wei Gao; Tianwei Xu

    2012-01-01

    As a powerful tool, ontology has been widely applied in social science, medicine science and computer science. In computer networks, especially, ontology is used for search extension, thus boost the quality of information retrieval. Ontology concept similarity calculation is an essential problem in these applications. A new method to get similarity between vertices on ontology graph is by machine learning, and multi-dividing algorithm is suitable for ontology problem. It is usually get an ont...

  11. Afya: Social and digital technologies that reach across the digital divide

    OpenAIRE

    Bishop, Ann Peterson; Bazzell, Imani; Mehra, Bharat; Smith, Cynthia

    2001-01-01

    This paper presents initiatives taken in the Afya project towards bridging the digital divide through social and digital literacy, equitable access, training, and content initiatives at the community level. As a participatory action research project, Afya (Swahili for "health") is designed to engage African American women in assessing and increasing their access to quality health information and services. Based on principles of social justice, the project is geared towards redefining relation...

  12. Atoms can be divided into three categories: polar, non-polar and hydrogen atom

    OpenAIRE

    You, Pei-lin

    2010-01-01

    Since the time of Rutherford 1911) physicists and chemists commonly believed that with no electric field, the nucleus of an atom is at the centre of the electron cloud, atoms do not have permanent electric dipole moment (EDM), so that there is no polar atom in nature. In the fact, the idea is untested hypothesis. After ten years of intense research, our experiments showed that atoms can be divided into three categories: polar, non-polar and hydrogen atom. Alkali atoms are al...

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

    OpenAIRE

    Arora, P. A.

    2012-01-01

    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...

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

    OpenAIRE

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

    2010-01-01

    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...

  15. Gender digital divide and online participation: A cross-national analysis

    OpenAIRE

    Chang, Younghoon; Shahzeidi, Mehri; Kim, Hyerin; Park, Myeong-cheol

    2012-01-01

    To achieve the information society for all, access for all is crucial. However, many countries have reported to have large gender discrepancies in online access and participation. This study empirically verified user perception data and compared the data across countries and genders to determine the differences between countries and genders. The results of surveys in Cambodia, Iran, and Korea verify that each aspect of the digital divide and online participation has a different influence on e...

  16. Digital divide – inequalities in level of implementation of new information and telecommunication technologies. Cross country study.

    OpenAIRE

    Ewa, Lechman

    2010-01-01

    In the paper presented, the author considers few aspects of the so-called “digital divide”. It is easily noticeable worldwide, that new information and communication technologies (ICTs) “possess” a great ability to spread, at high pace, among countries from all around the world. At the same time, we can see that ICTs are being implemented at different pace in difference economies. Different pace of ICTs implementation generates significant inequalities in level of usage and applicatio...

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

    OpenAIRE

    Yongchang Wang

    2009-01-01

    There have been substantial changes in the relationship between the PLA and the emerging private entrepreneurs since China’s reform and opening-up. As a consequence, these relations have shifted from the old model of political divide to a new model of social reconciliation, which could be described by four major indicators: recruiting policy, civil-military mutual support movement, the private sector’s engagement in military procurement and private employers’ participation i...

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

    OpenAIRE

    Li, Zheng; Keung, Jacky

    2013-01-01

    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...

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

    OpenAIRE

    Katie Brown; Campbell, Scott W.; Rich Ling

    2011-01-01

    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 ...

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

    OpenAIRE

    Lotriet, H; M. Matthee; Mazanderani, F

    2010-01-01

    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...

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

    Science.gov (United States)

    Reddy, Bodha venugopal; Reddy, N. Narender

    2012-07-01

    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.

  2. 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

  3. A Ka-band wide locking range frequency divider with high injection sensitivity

    Science.gov (United States)

    Faen, Liu; Zhigong, Wang; Zhiqun, Li; Qin, Li; Lu, Tang; Geliang, Yang; Zhu, Li

    2014-03-01

    This paper proposes a direct injection-locked frequency divider (ILFD) with a wide locking range in the Ka-band. A complementary cross-coupled architecture is used to enhance the overdriving voltage of the switch transistor so that the divider locking range is extended efficiently. New insights into the locking range and output power are proposed. A new method to analyze and optimize the injection sensitivity is presented and a layout technique to reduce the parasitics of the cross-coupled transistors is applied to decrease the frequency shift and the locking range degradation. The circuit is designed in a standard 90-nm CMOS process. The total locking range of the ILFD is 43.8% at 34.5 GHz with an incident power of -3.5 dBm. The divider IC consumes 3.6 mW of power at the supply voltage of 1.2 V The chip area including the pads is 0.5 × 0.5 mm2.

  4. 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

  5. Design of a water distribution system

    OpenAIRE

    Mavroudis, George

    1989-01-01

    The design of a water distribution system is a very useful project for all who deel with it. . For better explanation of the several steps followed until water appears in a community, this project was divided in to chapters. The first chapter refers to water its importance to all humanity and its uses. Chapter 2 gives a very briefly explanation about water quality - storage and treatment, necessary knowledge for a good Water Distribution System. All necessary des...

  6. Bridging the Digital Divide between Discrete and Continuous Space-Time Array Data to Enhance Accessibility to and Usability of NASA Earth Sciences Data for the Hydrological Community

    Science.gov (United States)

    Teng, W. L.; Maidment, D. R.; Vollmer, B.; Peters-Lidard, C. D.; Rui, H.; Strub, R.; Whiteaker, T.; Mocko, D. M.; Kirschbaum, D. B.

    2012-12-01

    A longstanding and significant "Digital Divide" in data representation exists between hydrology and climatology and meteorology. Typically, in hydrology, earth surface features are expressed as discrete spatial objects such as watersheds, river reaches, and point observation sites; and time varying data are contained in time series associated with these spatial objects. Long time histories of data may be associated with a single point or feature in space. In meteorology and climatology, remotely sensed observations and weather and climate model information are expressed as continuous spatial fields, with data sequenced in time from one data file to the next. Hydrology tends to be narrow in space and deep in time, while meteorology and climatology are broad in space and narrow in time. This Divide has been an obstacle, specifically, between the hydrological community, as represented by the Consortium of Universities for the Advancement of Hydrologic Science, Inc. (CUAHSI) and relevant data sets at the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC). CUAHSI has developed the Hydrologic Information System (HIS), which is built on international geospatial standards, with one of its aims to bridge the Divide. The opportunity costs of the Divide are high. It has largely prevented the routine access and use of NASA Earth sciences data by the hydrological and, more generally, geospatial community. This presentation describes a recently-begun NASA ACCESS project that addresses the Digital Divide problem. Progress to date is summarized; technical details are provided in a related presentation (Rui et al., Data Reorganization for Optimal Time Series Data Access, Analysis, and Visualization, IN016). Building on prior prototype efforts with EPA BASINS (Better Assessment Science Integrating point and Nonpoint Sources) and CUAHSI HIS, this project focuses on the following approaches to the problems of data discovery, access, and use: (1) Link HIS and GES DISC ontologies to facilitate data service registration in HIS catalog; (2) harvest NASA ECHO catalog with OpenSearch to generalize the solution beyond GES DISC; (3) develop HIS WaterOneFlow Web services for GES DISC data in OGC-compliant WaterML 2.0; (4) reorganize NASA data (land surface model outputs, satellite precipitation and soil moisture data) for optimal access as time series; (5) enhance HIS HydroDesktop client to better handle NASA data; and (6) develop hydrological use cases to guide implementation, and serve as metric for usefulness, of project technologies. This project should significantly extend NASA Earth sciences data to the large and important hydrological user community that has been, heretofore, mostly unable to easily access and use NASA data.

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

    OpenAIRE

    Martín, C.; Gudmundsson, G. H.

    2012-01-01

    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...

  8. Water management in an industry

    OpenAIRE

    Stavrinou, Charalambos

    1992-01-01

    This project deals with water management in an industry. First of all the whole industry is divided into sections, in Chapter 1 and the processes executed in each section are briefly described. In Chapter 2 water service for the industry is examined. This includes water treatment and water supply for various purposes. In this Chapter the sewage system of the industry is also ex~mined, i.e. where the discharged water and effluent from the various processes is discharged and where it t...

  9. Mapping and explaining the use of the left-right divide

    Scientific Electronic Library Online (English)

    André, Freire; Kats, Kivistik.

    Full Text Available 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.

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

    Directory of Open Access Journals (Sweden)

    Olugbade Oladokun

    2011-10-01

    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.

  11. Divide by 4 the emissions: the Negatep scenario; Diviser par 4 nos rejets: le scenario Negatep

    Energy Technology Data Exchange (ETDEWEB)

    Acket, C.; Bacher, P

    2007-01-15

    The Negatep scenario is proposed in the framework of the french energy policy, aiming to divide by 4 the CO{sub 2} emissions for 2050. After an evaluation of the today situation concerning the energy consumption and needs, the scenario proposes some ways of energy conservation in different sectors, other energy sources in place of the fossil fuels, the energy needs by sectors. The last part of the document provides the main consumption posts, the CO{sub 2} releases and the approach. (A.L.B.)

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

    Science.gov (United States)

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

    2003-04-04

    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.

  13. Penetration of a divided cystoperitoneal shunt catheter into the transverse colon inducing acute mastitis

    OpenAIRE

    Shimodaira, Kentaro; Miyakura, Yasuyuki; Sadatomo, Ai; Miyazaki, Chieko; Sasanuma, Hideki; Koinuma, Koji; Horie, Hisanaga; Hozumi, Yasuo; Lefor, Alan T.; YASUDA, YOSHIKAZU

    2013-01-01

    We report a rare case of acute mastitis caused by enteric organisms passing through a cystoperitoneal shunt catheter, which had penetrated into the colon. The patient is a 56-year-old woman who underwent shunt placement for cyst formation after surgery for meningioma at the age of 29. After 26 years, she suffered from a brain abscess and an attempt was made to surgically remove the indwelling catheter. Only part of the catheter could be removed, leaving a divided and ligated catheter in situ....

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

    OpenAIRE

    Langhammer, Rolf J.

    2004-01-01

    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...

  15. Purpose of protocol for kVp determination by invasive voltage divider

    International Nuclear Information System (INIS)

    This paper describes a protocol for the measurements of the maximum peak potential, absolute peak potential, average peak potential, practical peak potential, ripple and exposure time, through the invasive measurement made by high voltage divider installed between the high voltage generator and the x-ray tube. This protocol was developed based on International Electrotechnical Commission (IEC61676) and Report No. 14 of American Association of Physics in Medicine. Results are presented applying this protocol in X-ray tubes connected to a high frequency generator, average frequency generator and single phase generator. (author)

  16. eGY-Africa: addressing the digital divide for science in Africa

    Science.gov (United States)

    Baki, Paul; Nguno, Anna; Barton, Charles; Amaeshi, Larry; Tenthani, Chifundo; Petitdidier, Monique; Cottrell, Les

    2013-04-01

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

  17. CMOS DESIGN OF A MULTI_INPUT ANALOG MULTIPLIER AND DIVIDER CIRCUIT

    OpenAIRE

    Saatlo, Ali Naderi

    2014-01-01

    This paper proposes a CMOS current-mode multi_input analog multiplier and divider circuit based on a new method. Exponential and logarithmic functions are employed to realize the circuit which is used in neural network and fuzzy integrated systems. The major advantages of this multiplier are ability of having multi_input signals, and low Total Harmonic Distortion (THD). The circuit is designed and simulated using MATLAB software and HSPICE simulator by level 49 parameters (BSIM3v3) in 0.35?m...

  18. A CRITICAL EVALUATION OF INDIAN GOVERNMENT’S STRATEGIES TO BRIDGE DIGITAL DIVIDE

    OpenAIRE

    Nityesh BHATT

    2006-01-01

    Emergence of Information and Communication Technology (ICT) has been a landmark for India. In one way, this sunshine sector has been instrumental in the economic growth of country and has glorified its image in the whole world but on the other end, it has also created a digital divide in our society. BBC's Jill McGivering reports that the IT revolution is only changing some lives in the world's largest democracy. (Bagla,2005) A small section of society is harnessing it fully for their advanta...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-06-16

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

  20. A NOVEL DESIGN OF CURRENT MODE MULTIPLIER/DIVIDER CIRCUITS FOR ANALOG SIGNAL PROCESSING?

    Directory of Open Access Journals (Sweden)

    M.MOHANKUMAR

    2014-10-01

    Full Text Available In analog signal processing, current is used as input variables. In this design current mode multiplier /divider circuits is implemented in two modes. Thus implementing the circuit with proposed concept has very small linearity errors. In addition, high linearity is achieved because high accuracy current mirrors are adopted and the output current is insensitive to the temperature. The proposed computational structures are designed for implementing in 0.18-?m CMOS technology, with a lowvoltage operation (a supply voltage of 1.2 V excepting with the power consumptions are 55 and 70 ?W, respectively, while their frequency bandwidths are 79.6 and 59.7 MHz, respectively.

  1. Charge dividing mechanism on resistive electrode in position-sensitive detectors

    Energy Technology Data Exchange (ETDEWEB)

    Radeka, V; Rehak, P

    1978-10-01

    A complete charge-division mechanism, including both the diffusion and the electromagnetic wave propagation on resistive electrodes, is presented. The charge injected into such a transmission line divides between the two ends according to the ratio of resistancies and independently of the value of the line resistance, of the propagation mechanism and of the distribution of inductance and capacitance along the line. The shortest charge division time is achieved for Rl = 2..pi.. (L/C)/sup 1///sub 2/, where R, L, C are resistance, inductance and capacitance per unit length and l is the length of the line.

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

    DEFF Research Database (Denmark)

    Bartuccelli, Michele; Deane, Jonathan H.B.

    2010-01-01

    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.

  3. ZoneLib : A Simulink Library for Modeling Zone Divided Climate Dynamics

    DEFF Research Database (Denmark)

    Jessen, Jan Jacob; SchiØler, Henrik

    2006-01-01

    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.

  4. 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

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

    Directory of Open Access Journals (Sweden)

    C. Martín

    2012-06-01

    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.

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

    OpenAIRE

    Falkenmark, Malin

    2003-01-01

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

  7. Magnetized Water and Memory Meter

    Directory of Open Access Journals (Sweden)

    Ashraf Kotb

    2013-08-01

    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.

  8. Sector Dividing Method in Enroute Radar Airspace with Unbalanced Traffic Distribution

    Directory of Open Access Journals (Sweden)

    Zhijian Ye

    2013-06-01

    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.

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

    Science.gov (United States)

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

    2014-01-01

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

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

    Science.gov (United States)

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

    2014-06-01

    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

  11. Application of partially diabatic divided wall column to floating liquefied natural gas plant

    International Nuclear Information System (INIS)

    The offshore operation of chemical plant requires the compactness of process equipments due to its harsh environment. A DWC (divided wall column), a compact ternary separator, is a good candidate for distillation process in the offshore operation. In this study the DWC is applied to the offshore FLNG (floating liquefied natural gas) plant, but high utility cost is required in the application because of the large difference of boiling points among feed components. A partially diabatic DWC is proposed for the reduction of the operating cost here, and its design procedure is presented along with performance and economic evaluations and the examination of thermodynamic efficiency as well. The heating duty of the proposed DWC including tray heat transfer is 35% less than that of the conventional system, and the cooling duty is 18% less. The evaluation indicates that some 16% less utility cost is used in the DWC compared with the conventional system, though 7% more investment is required. The exergy loss is reduced by 12%, and the thermodynamic efficiency is improved by 3.3 percentage point over the conventional system. - Highlights: • Diabatic divided wall column for FLNG (floating liquefied natural gas) plant. • Compact column for offshore operation. • 35% less heating duty required. • 16% lower utility necessary. • Exergy loss reduced by 12%

  12. Clinical psychology and disability studies: bridging the disciplinary divide on mental health and disability.

    Science.gov (United States)

    Simpson, Jane; Thomas, Carol

    2014-09-22

    Abstract Purpose: Clinical psychology and disability studies have traditionally occupied very different academic, philosophical and political spaces. However, this paper aims to illustrate the positive consequences and implications of attempts to understand and bridge this disciplinary divide. Method: A narrative review format was used with evidence selected pragmatically as opposed to systematically. The construction of the argument determined the evidence selected. Results: The concept of psycho-emotional disablism, which originated within disability studies, is argued to be a useful concept to bridge the divide between understandings of distress from both disability studies and clinical psychology perspectives. However, this can be usefully augmented by psychological research on the mechanisms through which disablism can affect individuals. Conclusion: Perspectives from both disability studies and clinical psychology can be usefully combined to bring important new perspectives; combined, these perspectives should help - on theoretical, service and social levels - to improve the mental health of disabled people. Implications for Rehabilitation Mental health is an important determinant of overall health-related quality of life and psychological therapy should be available for those disabled people who would value it. Psychological therapists working with disabled people should be more aware of the challenging social context in which disabled people live. Understandings of distress should not just include individual factors but also incorporate the psychological impact of stresses caused by societal barriers preventing inclusion. Psychologists should be more willing to work and engage at a societal and political level to influence change. PMID:25243770

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

    Directory of Open Access Journals (Sweden)

    Debbra Toria Nipo

    2014-09-01

    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.

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

    KAUST Repository

    Luo, Xiaodong

    2014-12-01

    This study considers the data assimilation problem in coupled systems, which consists of two components (subsystems) 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 subsystems into one augmented state vector, so that a standard ensemble Kalman filter (EnKF) can be directly applied. This work presents a divided state-space estimation strategy, in which data assimilation is carried out with respect to each individual subsystem, involving quantities from the subsystem itself and correlated quantities from other coupled subsystems. On top of the divided state-space estimation strategy, the authors also consider the possibility of running the subsystems 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 multiscale Lorenz 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-offbetween efficiency and accuracy.

  15. 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

  16. Controlling hollow relativistic electron beam orbits with an inductive current divider

    Science.gov (United States)

    Swanekamp, S. B.; Richardson, A. S.; Angus, J. R.; Cooperstein, G.; Hinshelwood, D. D.; Ottinger, P. F.; Rittersdorf, I. M.; Schumer, J. W.; Weber, B. V.; Zier, J. C.

    2015-02-01

    A passive method for controlling the trajectory of an intense, hollow electron beam is proposed using a vacuum structure that inductively splits the beam's return current. A central post carries a portion of the return current (I1), while the outer conductor carries the remainder (I2). An envelope equation appropriate for a hollow electron beam is derived and applied to the current divider. The force on the beam trajectory is shown to be proportional to (I2-I1), while the average force on the envelope (the beam width) is proportional to the beam current Ib = (I2 + I1). The values of I1 and I2 depend on the inductances in the return-current path geometries. Proper choice of the return-current geometries determines these inductances and offers control over the beam trajectory. Solutions using realistic beam parameters show that, for appropriate choices of the return-current-path geometry, the inductive current divider can produce a beam that is both pinched and straightened so that it approaches a target at near-normal incidence with a beam diameter that is on the order of a few mm.

  17. 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

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

    Directory of Open Access Journals (Sweden)

    Boran A. AL-Rababah

    2010-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Yan Liu

    2013-07-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Schloman, B

    2004-05-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Bouchra Rahali

    2014-01-01

    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.

  2. Dividing by four CO2 releases due to energy: the Negatep scenario

    International Nuclear Information System (INIS)

    The Negatep scenario aims at dividing CO2 releases by 4, which means, more or less, dividing the consumption of fossil energies by the same factor, in order to comply with the French 2005 energy act. After a description of the situation in 2006, of trends, and a recall of the objectives defined by the 'Grenelle de l'Environnement' regarding energy savings and renewable energies, the authors show that reaching such a reduction requires to: decrease to nearly zero oil and gas in the residential and tertiary sectors, reduce significantly the use of oil in the transport sector, reduce significantly the use of fossil fuels in industry, increase massively the share of electricity in the energy mix, maintain the share of nuclear in the electricity generation and, as long as the storage of electricity is not developed, limit the share of intermittent energies to a level compatible with that of gas turbines. The study shows that the proposed measures can fulfill the objectives for 2020 proposed by the 'Grenelle de l'Environnement'

  3. Decolorization and mineralization of Orange G azo dye solutions by anodic oxidation with a boron-doped diamond anode in divided and undivided tank reactors

    International Nuclear Information System (INIS)

    Highlights: • Acidic Orange G azo dye solutions completely degraded by anodic oxidation with BDD. • Quicker decolorization and mineralization in a divided than an undivided cell. • Similar time needed for total decolorization and disappearance of Orange G. • Maleic, tartronic, acetic, formic, oxalic and oxamic acids as generated carboxylic acids. • Ammonium and sulfate as main inorganic ions released during dye mineralization. - Abstract: The decolorization and mineralization of 100 cm3 of 0.52-6.34 mmol dm?3 Orange G azo dye solutions at pH 3.0 and current density between 33.3 and 150 mA cm?2 have been studied by anodic oxidation (AO) using a divided or undivided tank reactor with a boron-doped diamond (BDD) anode and a stainless steel cathode. In both systems, organics were destroyed by hydroxyl radicals generated at the BDD anode from water oxidation. Solutions with 0.52 mmol dm?3 of the dye were completely decolorized in both cells, more rapidly at greater current density. The divided cell always gave faster decolorization than the undivided one. Overall mineralization in the divided tank reactor was attained in less than 330 min operating at current densities ? 66.7 mA cm?2, whereas in the undivided cell, this was feasible at times as long as 420 min for 150 mA cm?2. For Orange G contents up to 6.34 mmol dm?3, total mineralization at 100 mA cm?2 was also more easily reached in the divided cell. The mineralization current efficiency always rose at lower current density and higher dye content. The dye decayed obeying a pseudo-first-order kinetics and its apparent rate constant increased at higher current density. A similar electrolysis time was required for total decolorization and disappearance of Orange G, indicating that aromatic by-products were rapidly destroyed and did not accumulate in the medium. Final carboxylic acids like maleic, tartronic, acetic, formic, oxalic and oxamic were generated, whereas ammonium and sulfate were the main inorganic ions released during Orange G mineralization

  4. Aromatic acids from biomass burning in the WAIS Divide ice core

    Science.gov (United States)

    Saltzman, E. S.; Grieman, M. M.; McConnell, J.; Cole-Dai, J.

    2014-12-01

    Biomass burning plays an important role in atmospheric chemistry, carbon cycling, and climate. The global long-term history of biomass burning is not well established, making it difficult to study the relationship between burning, climate change, and atmospheric chemistry. Here we present the Antarctic ice core records of vanillic acid and p-hydroxybenzoic from the WAIS Divide ice core covering the past 2.4-30 kyrs BP. These molecules are derived from incomplete combustion of plant lignin and transported/deposited as aerosols onto the ice sheet. Vanillic and p-hydroxybenzoic acids are associated with combustion of conifers and grasses, respectively, but are not uniquely derived from these plant types. Analyses were done using ion chromatography with electrospray MS/MS detection in negative ion SRM mode. Vanillic p-hydroxybenzoic acid exhibited a range from baseline levels near 0.01 ppb (detection limit) to >0.5 ppb. Vanillic acid exhibited striking millennial scale variability during late glacial period, with 6 major peaks between 25 and 13.5 kyrs BP, with a spacing of 1.5-3 kyrs and durations of up to 1 kyr. There are no comparable peaks during the early-mid Holocene. A late Holocene vanillic acid peak starts at 3 kyrs BP. p-Hydroxybenzoic acid shares the same major peaks as vanillic acid from 25-13.5 kyrs BP, but exhibits additional variability of comparable magnitude throughout the WAIS Divide 2.4-30 kyr record. These paleo records should be viewed as qualitative burning proxies because 1) a wide range of aerosol composition and sizes can be generated from combustion of various plant materials under different conditions, and 2) the ice core levels of aromatic acids may reflect changes in source regions, transport and atmospheric removal efficiency, and postdepositional mobilization. The major peaks in the WAIS Divide aromatic acid records most likely do not represent changes in global biomass burning emissions, because they are not highly correlated with variations in atmospheric methane. Such caveats notwithstanding, these records provide a surprising new picture of the long-term variability in the deposition of burning-derived aerosols to the Antarctic ice sheet.

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

    Directory of Open Access Journals (Sweden)

    Segarani Naidoo

    2012-12-01

    Full Text Available 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 differentlevels of literacy, information and otherwise. The problem that this study addressed was the impact of having both digitallyadvantaged and digitally disadvantaged students in the same information literacy classroom, expecting them to reachlearning outcomes without frustrating students from either group. The objective of the study was to investigate the impactof the digital divide on IL training of ECP students at the DUT and to recommend guidelines for teaching and learning of ILthat would accommodate both digitally advantaged and digitally disadvantaged students. The study employed a mixedmethod approach in its research design. Data was collected from ECP students (of 2010 by means of a questionnaire; aninterview schedule was used to collect data from Subject Librarians involved in teaching the IL module to ECP students; aseparate interview schedule was used to collect data from the ECP Coordinator. Qualitative and quantitative datacollected were prepared for analysis by means of content analysis and numerical coding, respectively and then subjectedto statistical analysis via SPSS, which produced percentage and frequency distributions to ascertain findings. The findingsof the study revealed that the digital divide does impact on IL training in ways such as: slowing down the progress of ILlessons; basic computer skills need to be taught in the IL classroom; and that digitally disadvantaged students find itdifficult to follow online lessons while advantaged students already have the expertise to access online information. Basedon these findings the study recommended computer literacy training should precede IL training and that various creativeteaching and learning methods such as group work, online tutorials, games and interactive websites should beincorporated into IL education to accommodate both digitally advantaged and digitally disadvantaged students in the ILclassroom.

  6. New Frontiers in the Digital Divide : Revisiting Policy for Digital Inclusion

    DEFF Research Database (Denmark)

    Jæger, Birgit

    In a new strategy for e-government, the Danish government set the goal that in 2015 all contacts between citizens and public authorities must be conducted electronically. In accordance with EU’s strategy for e-government every citizen ought to have equal access to public services, hence the question is: How to form a policy for digital inclusion where nobody is left behind? In continuation of the EU policy it seems reasonable to argue that the public authorities now has an obligation to ‘dress up’ the citizens to serve themselves through the public e-services. Hence, policies and actions for digital inclusion becomes a central theme for the implementation of the new e-government strategy. Until now it has been voluntary whether or not citizens want to use ICT and a lot of especially senior citizens have chosen not to use the technology. However, senior citizens are not the only group affected of the e-government strategy. New frontiers in the digital divide are opening and a new group of excluded become visible: the youngsters. In this way, one of the leading Danish newspapers reports that young people lines up in town halls to get help to fill out forms, which are already available on the internet. The analysis in this paper is based on a multidisciplinary theoretical approach drawing on theories of the digital divide, theories of domestication of technology, and theories about the interplay between users and technology developed in the field of STS (Science, Technology and Society). In continuation of this theoretical framework the analysis is conducted as a mixed methods research where different kinds of knowledge are included. Hence, to analyze the Danish digital divide I draw on statistics developed by Statistics Denmark – the national agency for statistic – as well as a comprehensive qualitative study of senior citizens’ usage of ICT (Jæger, 2005). For the analysis of the policy I draw on a literature study of policy papers (Jæger & Löfgren 2010) as well as six qualitative interviews with key politicians – including the Minister of Science and Technology – and key civil servant.

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

    Science.gov (United States)

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

    2011-12-01

    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.

  8. Correction of divided renal clearance studies - a comparison of renal depths

    International Nuclear Information System (INIS)

    Differences in renal depth can be determined by ultrasound investigation and profile measurements of a digitalised lateral renal scintigram. Both methods are simple and equally suitable for determining renal depth. Amongst 42 patients there were three in whom there were considerable differences in renal depth in the supine position, and seven patients with a similar difference when they were sitting upright. A correction for renal depth resulted in a reduction in the error obtained on divided renal clearance studies. Measurements on a renal phantom designed to obtain the half-value layer of 131J and 99sup(m)Tc provide quantitative data for the correction. The correction is less easily carried out when renal depth differences occur in the sitting position than when the patient was lying down. Determination of renal depth when the patient is lying down can be confined to individual cases which can be selected from the total clinical material. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-12-31

    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.

  10. 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.

  11. College Students Perception of the Second-Level Digital Divide: An Empirical Analysis

    Directory of Open Access Journals (Sweden)

    Fanbin Zeng

    2011-05-01

    Full Text Available The goal of this study was to take a comprehensive measure to the second-level digital divide, along with analyzing the various factors, and finding out the prominent factors. This study comes up with the hypothesis based on three Theoretical framework of Knowledge gap theory, Use and gratifications theory, Self-efficacy and attitude theory. Based on a survey on students of Jinan University (N=302, Multiple linear regression shows that the sensibility factors of Internet use, including the attitude toward the Internet and the Internet self-efficacy, have significant positive effects on the level of Internet use, including the time of Internet use and the index of Internet use about studying and working.

  12. Penetration of a divided cystoperitoneal shunt catheter into the transverse colon inducing acute mastitis.

    Science.gov (United States)

    Shimodaira, Kentaro; Miyakura, Yasuyuki; Sadatomo, Ai; Miyazaki, Chieko; Sasanuma, Hideki; Koinuma, Koji; Horie, Hisanaga; Hozumi, Yasuo; Lefor, Alan T; Yasuda, Yoshikazu

    2013-01-01

    We report a rare case of acute mastitis caused by enteric organisms passing through a cystoperitoneal shunt catheter, which had penetrated into the colon. The patient is a 56-year-old woman who underwent shunt placement for cyst formation after surgery for meningioma at the age of 29. After 26 years, she suffered from a brain abscess and an attempt was made to surgically remove the indwelling catheter. Only part of the catheter could be removed, leaving a divided and ligated catheter in situ. A year later, she described right-breast pain. CT showed that the catheter had migrated into the colon, followed by colonoscopy confirming that the catheter had indeed penetrated the colon. The breast to the abdomen segment of the catheter was exteriorized through the right-anterior chest wall without laparotomy. A patient who presents with acute mastitis and has previously undergone shunt surgery should have a careful assessment of the entire catheter. PMID:24964447

  13. Toward a High Performance Tile Divide and Conquer Algorithm for the Dense Symmetric Eigenvalue Problem

    KAUST Repository

    Haidar, Azzam

    2012-01-01

    Classical solvers for the dense symmetric eigenvalue problem suffer from the first step, which involves a reduction to tridiagonal form that is dominated by the cost of accessing memory during the panel factorization. The solution is to reduce the matrix to a banded form, which then requires the eigenvalues of the banded matrix to be computed. The standard divide and conquer algorithm can be modified for this purpose. The paper combines this insight with tile algorithms that can be scheduled via a dynamic runtime system to multicore architectures. A detailed analysis of performance and accuracy is included. Performance improvements of 14-fold and 4-fold speedups are reported relative to LAPACK and Intel\\'s Math Kernel Library.

  14. 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.

  15. Long Division Unites or Long Union Divides: a Model for Social Network Evolution

    Science.gov (United States)

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

    2013-03-01

    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 the division of nodes. We propose a phenomenological modeling, inspired by the maxim “long union divides and long division unites" 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, and interaction, 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.

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

    CERN Document Server

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

    2013-01-01

    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.

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

    DEFF Research Database (Denmark)

    Brown, Katie; Campbell, Scott

    2011-01-01

    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 general and teen citizenship in particular. Yet the cost of this move toward equal access is absorbed by those who can least afford it: Teenagers from low income households. Using survey and focus group data from a national study of “Teens and Mobile Phone Use” (released by Pew and the University of Michigan in 2010), this article helps identify and explain this and other emergent trends for teen use (as well as non-use) of the internet through mobile phones.

  18. The Connect America Fund hopes to give rural Americans broadband access, bridging the "digital divide".

    Science.gov (United States)

    Grinnell, Max

    2011-12-09

    Sweet land of subsidyhttp://www.economist.com/node/21541061Rural broadband access could be key to economic developmenthttp://www.wisbusiness.com/index.iml?Article=255010New Research Shows Digital Divide Still Persists in the U.S.http://www.nonprofitquarterly.org/index.php?option=com_content&view=article&id=17531:new-research-shows-digital-divide-still-persists-in-the-us&catid=155:nonprofit-newswire&Itemid=986Exploring the Digital Nation-Computer and Internet Use at Home [pdf]http://www.esa.doc.gov/Reports/exploring-digital-nation-computer-and-internet-use-homeConnecting Americahttp://www.fcc.gov/encyclopedia/connecting-americaA Brief History of the Rural Electric and Telephone Programshttp://www.rurdev.usda.gov/rd/70th/rea-history.pdfTishomingo County in Mississippi and Aroostook County in Maine share a similar problem: Both places have little or no access to reliable broadband networks. On the surface, this might seem to be a rather minor concern. However, many policymakers and politicians agree with local administrators and citizens, that increased access to broadband networks will increase rural areas ability to compete for new businesses, such as call centers. Recently, the Federal Communications Commission (FCC) released details of an order that would direct $4.5 billion a year into the newly created Connect America Fund (CAF). The hope is that the work of the CAF will give 7 million rural Americans access to reliable high-speed Internet connections over the next six years. Bridging the "digital divide" may be a difficult proposition, and there are reasons to believe that it may not be the best use such funds. In 2006, the Government Accountability Office expressed concerned that spotty data might undermine the usefulness of rural-broadband subsidies. Another issue is that some of these communities may already be served by existing wireless 3G networks, which means that they are not technically "underserved".The first link will take visitors to a recent piece from The Economist about the proposed expansion of broadband service in the United States. The second link leads to an article from this Tuesday's Wisconsin Business about the importance of broadband Internet access throughout rural Wisconsin. Moving along, the third link will whisk users away to a compelling article from The Nonprofit Quarterly about the persistence of a digital divide in the United States. The fourth link will take users to an excellent report from the United States Department of Commerce about the world of broadband connectivity in the United States. The fifth link leads to a nice report from the FCC about their initiative on "Connecting America", complete with maps and an executive summary. Finally, the last link will take interested parties to a 62-page report on the history of the Rural Electric and Telephone programs in the US.

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

    Science.gov (United States)

    Stier, Haya

    2015-01-01

    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

  20. Functional mobility in a divided attention task in older adults with cognitive impairment.

    Science.gov (United States)

    de Melo Borges, Sheila; Radanovic, Márcia; Forlenza, Orestes Vicente

    2015-01-01

    Motor disorders may occur in mild cognitive impairment (MCI) and at early stages of Alzheimer's disease (AD), particularly under divided attention conditions. We examined functional mobility in 104 older adults (42 with MCI, 26 with mild AD, and 36 cognitively healthy) using the Timed Up and Go test (TUG) under 4 experimental conditions: TUG single task, TUG plus a cognitive task, TUG plus a manual task, and TUG plus a cognitive and a manual task. Statistically significant differences in mean time of execution were found in all four experimental conditions when comparing MCI and controls (p .8, p .7, p < .001 for MCI vs. AD). The authors conclude that functional motor deficits occurring in MCI can be assessed by the TUG test, in single or dual task modality. PMID:25610990

  1. Characteristics of Optimal Function for Ontology Similarity Measure via Multi-dividing

    Directory of Open Access Journals (Sweden)

    Wei Gao

    2012-08-01

    Full Text Available As a powerful tool, ontology has been widely applied in social science, medicine science and computer science. In computer networks, especially, ontology is used for search extension, thus boost the quality of information retrieval. Ontology concept similarity calculation is an essential problem in these applications. A new method to get similarity between vertices on ontology graph is by machine learning, and multi-dividing algorithm is suitable for ontology problem. It is usually get an ontology function which maps the vertices of ontology graph to real numbers. Such function is given by learning a training sample which contains a subset of vertices of ontology graph. In this paper, we study the properties of best ontology function for this method. Some results under different loss functions are given.

  2. Evaluating the Spectrum of Unlocked Injection Frequency Dividers in Pulling Mode

    Directory of Open Access Journals (Sweden)

    Alessandro Lo Schiavo

    2013-09-01

    Full Text Available We study the phenomenon of periodic pulling which occurs in certain integrated microcircuits of relevant interest in applications, namely the injection-locked frequency dividers (ILFDs. They are modelled as second-order driven oscillators working in the subharmonic (secondary resonance regime, i.e., when the self-oscillating frequency is close (resonant to an integer submultiple n of the driving frequency. Under the assumption of weak injection, we find the spectrum of the system’s oscillatory response in the unlocked mode through closed-form expressions, showing that such spectrum is double-sided and asymmetric, unlike the single-sided spectrum of systems with primary resonance (n=1. An analytical expression for the amplitude modulation of the oscillatory response is also presented. Numerical results are presented to support theoretical relations derived.

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

    Directory of Open Access Journals (Sweden)

    Jing Lei

    2012-03-01

    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.

  4. Block-adaptive quantum mechanics: an adaptive divide-and-conquer approach to interactive quantum chemistry.

    Science.gov (United States)

    Bosson, Maël; Grudinin, Sergei; Redon, Stephane

    2013-03-01

    We present a novel Block-Adaptive Quantum Mechanics (BAQM) approach to interactive quantum chemistry. Although quantum chemistry models are known to be computationally demanding, we achieve interactive rates by focusing computational resources on the most active parts of the system. BAQM is based on a divide-and-conquer technique and constrains some nucleus positions and some electronic degrees of freedom on the fly to simplify the simulation. As a result, each time step may be performed significantly faster, which in turn may accelerate attraction to the neighboring local minima. By applying our approach to the nonself-consistent Atom Superposition and Electron Delocalization Molecular Orbital theory, we demonstrate interactive rates and efficient virtual prototyping for systems containing more than a thousand of atoms on a standard desktop computer. PMID:23108532

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

    Directory of Open Access Journals (Sweden)

    Clara Himmelheber

    2014-10-01

    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.

  6. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

    Yang Songyan [Engineering Mechanics Department, Ontario Power Generation - Nuclear, 889 Brock Road, Pickering, Ontario, L1W 3J2 (Canada)], E-mail: songyan.yang@opg.com; Manning, Bruce W. [Engineering Mechanics Department, Ontario Power Generation - Nuclear, 889 Brock Road, Pickering, Ontario, L1W 3J2 (Canada)

    2009-11-15

    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.

  8. Dual-Band CMOS Injection-Locked Frequency Divider with Variable Division Ratio

    Science.gov (United States)

    Jang, Sheng-Lyang; Lin, Chih-Yeh; Liu, Cheng-Chen; Huang, Jhin-Fang

    A dual band 0.18µm CMOS LC-tank injection locked frequency divider (ILFD) is proposed. The ILFD circuit is realized with a cross-coupled pMOS LC-tank oscillator with an inductor switch for frequency band selection. The self-oscillating VCO is injection-locked by nth-harmonic input to obtain the division factor of n. The division ratio of 1, 2, and 3 has been found for the proposed ILFD. Measurement results show that at the supply voltage of 1.1V, the free-running frequency is from 2.28(3.09)GHz to 2.78(3.72)GHz for the low- (high-) frequency band. The power consumption of the ILFD core is 3.7mW (6.2mW) at low (high) band. The total area including the output buffer and the pads is 0.841 × 0.764mm2.

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

    DEFF Research Database (Denmark)

    Berthold, Jost; Dieterle, Mischa

    2009-01-01

    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

  10. Second-Level Digital Divide Mapping Differences in People's Online Skills

    CERN Document Server

    Hargittai, E

    2001-01-01

    Much of the existing approach to the digital divide suffers from an important limitation. It is based on a binary classification of Internet use by only considering whether someone is or is not an Internet user. To remedy this shortcoming, this project looks at the differences in people's level of skill with respect to finding information online. Findings suggest that people search for content in a myriad of ways and there is a large variance in how long people take to find various types of information online. Data are collected to see how user demographics, users' social support networks, people's experience with the medium, and their autonomy of use influence their level of user sophistication.

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

    Directory of Open Access Journals (Sweden)

    Jääskeläinen

    2003-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

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

    2014-09-01

    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.

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

    Directory of Open Access Journals (Sweden)

    V. Prajzler

    2013-04-01

    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.

  14. Modeling fracture toughness of functionally graded steels in crack divider configuration

    International Nuclear Information System (INIS)

    Fracture toughness of functionally graded steels in crack divider configuration has been modeled. By utilizing plain carbon and austenitic stainless steel slices with various thicknesses and arrangements as electroslag remelting electrodes, functionally graded steels were produced. The fracture toughness of the functionally graded steels was found to depend on the type, volume fraction and position of the phases present. According to the area under the stress–strain curve of each layer in the functionally graded composites, a mathematical model has been presented for fracture toughness prediction using the rule of mixtures. In addition, the fracture toughness of the composites has been simulated by the 3D dynamic finite element method. There is good agreement between experimental results and those acquired from the numerical and mathematical models

  15. Water, Water Everywhere

    Science.gov (United States)

    Keeler, Rusty

    2009-01-01

    Everybody knows that children love water and how great water play is for children. The author discusses ways to add water to one's playscape that fully comply with health and safety regulations and are still fun for children. He stresses the importance of creating water play that provides children with the opportunity to interact with water.

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

    Science.gov (United States)

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

    2014-01-01

    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

  17. Amyloid precursor protein (APP) affects global protein synthesis in dividing human cells.

    Science.gov (United States)

    Sobol, Anna; Galluzzo, Paola; Liang, Shuang; Rambo, Brittany; Skucha, Sylvia; Weber, Megan J; Alani, Sara; Bocchetta, Maurizio

    2015-05-01

    Hypoxic non-small cell lung cancer (NSCLC) is dependent on Notch-1 signaling for survival. Targeting Notch-1 by means of ?-secretase inhibitors (GSI) proved effective in killing hypoxic NSCLC. Post-mortem analysis of GSI-treated, NSCLC-burdened mice suggested enhanced phosphorylation of 4E-BP1 at threonines 37/46 in hypoxic tumor tissues. In vitro dissection of this phenomenon revealed that Amyloid Precursor Protein (APP) inhibition was responsible for a non-canonical 4E-BP1 phosphorylation pattern rearrangement-a process, in part, mediated by APP regulation of the pseudophosphatase Styx. Upon APP depletion we observed modifications of eIF-4F composition indicating increased recruitment of eIF-4A to the mRNA cap. This phenomenon was supported by the observation that cells with depleted APP were partially resistant to silvestrol, an antibiotic that interferes with eIF-4A assembly into eIF-4F complexes. APP downregulation in dividing human cells increased the rate of global protein synthesis, both cap- and IRES-dependent. Such an increase seemed independent of mTOR inhibition. After administration of Torin-1, APP downregulation and Mechanistic Target of Rapamycin Complex 1 (mTORC-1) inhibition affected 4E-BP1 phosphorylation and global protein synthesis in opposite fashions. Additional investigations indicated that APP operates independently of mTORC-1. Key phenomena described in this study were reversed by overexpression of the APP C-terminal domain. The presented data suggest that APP may be a novel regulator of protein synthesis in dividing human cells, both cancerous and primary. Furthermore, APP appears to affect translation initiation using mechanisms seemingly dissimilar to mTORC-1 regulation of cap-dependent protein synthesis. PMID:25283437

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

    Directory of Open Access Journals (Sweden)

    Kamgar

    2009-04-01

    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.

  19. Magnetized Water and Memory Meter

    OpenAIRE

    Ashraf Kotb

    2013-01-01

    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...

  20. Water, Water Everywhere

    Science.gov (United States)

    NASA

    This is a short NASA video on the water cycle. The video shows the importance of the water cycle to nearly every natural process on Earth and illustrates how tightly coupled the water cycle is to climate.

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

    CERN Document Server

    Bastos, M C; Hammarquist, M

    2011-01-01

    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.

  2. A High-voltage Reference Testbed for the Evaluation of High-voltage Dividers for Pulsed Applications

    CERN Document Server

    Bastos, M Cerqueira; Bergman, A

    2010-01-01

    The design, evaluation and commissioning of a high voltage reference testbed for pulsed applications to be used in the precision testing of high voltage dividers is described. The testbed is composed of a pulsed power supply, a reference divider based on compressed gas capacitor technology and an acquisition system which makes use of the fast measurement capabilities of the HP 3458 DVM. Results of the evaluation of the reference system are presented.

  3. COMPARATIVE EFFECTS OF DIAZEPAM INFUSION AND DIVIDED DOSES OF DIAZEPAM ON THE TREATMENT OF ABSENCE STATUS EPILEPTICUS

    OpenAIRE

    Afshar Khas, L.; Karimzadeh, P.; Mosavat, A.

    2009-01-01

    ObjectiveAbsence status epilepticus (ASE) is a common form of nonconvulsive status epilepcticus. It is characterized by loss of consciousness with spike and wave discharges in EEG simultaneously. The most effective treatment of ASE is diazepam, either infusion or in divided doses; the former is more expensive since patients must be admitted in an Intensive Care Unit. The aim of this study was to evaluate and compare the efficacy of diazepam infusion and parenteral diazepam in divided doses i...

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

    Directory of Open Access Journals (Sweden)

    Susan E. Russell

    2013-04-01

    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.

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

    Science.gov (United States)

    Kelly, Douglas A

    2014-10-01

    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

  6. The potential, limitations, and challenges of divide and conquer quantum electronic structure calculations on energetic materials.

    Energy Technology Data Exchange (ETDEWEB)

    Tucker, Jon R.; Magyar, Rudolph J.

    2012-02-01

    High explosives are an important class of energetic materials used in many weapons applications. Even with modern computers, the simulation of the dynamic chemical reactions and energy release is exceedingly challenging. While the scale of the detonation process may be macroscopic, the dynamic bond breaking responsible for the explosive release of energy is fundamentally quantum mechanical. Thus, any method that does not adequately describe bonding is destined to lack predictive capability on some level. Performing quantum mechanics calculations on systems with more than dozens of atoms is a gargantuan task, and severe approximation schemes must be employed in practical calculations. We have developed and tested a divide and conquer (DnC) scheme to obtain total energies, forces, and harmonic frequencies within semi-empirical quantum mechanics. The method is intended as an approximate but faster solution to the full problem and is possible due to the sparsity of the density matrix in many applications. The resulting total energy calculation scales linearly as the number of subsystems, and the method provides a path-forward to quantum mechanical simulations of millions of atoms.

  7. Extraction of uranium low-grade ores from Great Divide Basin, Wyoming. National Uranium Resource Evaluation

    International Nuclear Information System (INIS)

    The US Bureau of Mines is investigating the leachability of carbonaceous uranium ore samples submitted by the DOE under an Interagency Agreement. Studies on eight samples from the Great Divide Basin, Wyoming, are the basis of this report. The uranium content of the eight ore samples ranged from 0.003 to 0.03% U3O8 and contained 0.7 to 45% organic carbon. Experiments were performed to determine the feasibility of extracting uranium using acid leaching, roast-acid leaching and pressure leaching techniques. Acid leaching with 600 lb/ton H2SO4 plus 10 lb/ton NaClO3 for 18 h at 700C extracted 65 to 83% of the uranium. One sample responded best to a roast-leach treatment. When roasting for 4 h at 5000C followed by acid leaching of the calcine using 600 lb/ton H2SO4, the uranium extraction was 82%. Two of the samples responded best to an oxidative pressure leach for 3 h at 2000C under a total pressure of 260 psig; uranium extractions were 78 and 82%

  8. The private-public law divide : Does this legal design create an abyss to children's welfare?

    DEFF Research Database (Denmark)

    Svendsen, Idamarie Leth; Kronborg, Annette

    2013-01-01

    In a Scandinavian perspective, the family and the individual have changed places during the 20th Century. Today, the law takes its starting point in the individual - not in the family. A consequence of this development is that it is no longer legally possible to relate the good family to a particular societal institution. Marriage as an institution has been individualized and the goodness of the family has to relate to the well-being of the individuals instead. This article shows that within this historical development the private-public law divide has not been seriously challenged. The inconsistencies stemming from it are demonstrated and it is shown how they imply a legal design more preoccupied with traditional divisions of power and positions than with an interest in the reality of the people it is aimed at. In the article it is argued from within the best ingerest principle that the historical development neccessitates a re-thinking of the distinction between child welfare law and family law. It shows how the distinction is nationally and institutionally embedded. Further, that the distinction has only been superficially adressed by the CRC Committee.

  9. Synthesis of finely divided molybdenum sulfide nanoparticles in propylene carbonate solution

    Energy Technology Data Exchange (ETDEWEB)

    Afanasiev, Pavel, E-mail: pavel.afanasiev@ircelyon.univ-lyon1.fr

    2014-05-01

    Molybdenum sulfide nanoparticles have been prepared from the reflux solution reaction involving ammonium heptamolybdate and elemental sulfur in propylene carbonate. Addition to the reaction mixture of starch as a natural capping agent leads to lesser agglomeration and smaller size of the particles. Nanoparticles of MoS{sub x} (x?4) of 10–30 nm size are highly divided and form stable colloidal suspensions in organic solvents. Mo K edge EXAFS of the amorphous materials shows rapid exchange of oxygen to sulfur in the molybdenum coordination sphere during the solution reaction. Thermal treatment of the amorphous sulfides MoS{sub x} under nitrogen or hydrogen flow at 400 °C allows obtaining mesoporous MoS{sub 2} materials with very high pore volume and specific surface area, up to 0.45 cm{sup 3}/g and 190 m{sup 2}/g, respectively. The new materials show good potential for the application as unsupported hydrotreating catalysts. - Graphical abstract: Solution reaction in propylene carbonate allows preparing weakly agglomerated molybdenum sulfide with particle size 20 nm and advantageous catalytic properties. - Highlights: • Solution reaction in propylene carbonate yields MoS{sub x} particles near 20 nm size. • Addition of starch as capping agent reduces particles size and hinder agglomeration. • EXAFS at Mo K edge shows rapid oxygen to sulfur exchange in the solution. • Thermal treatment leads to MoS{sub 2} with very high porosity and surface area.

  10. [Excision: the new prohibition that divides the society. Press review: Senegal].

    Science.gov (United States)

    1999-12-01

    Approximately 700,000 women in Senegal have suffered female genital mutilation (FGM). Now, following a vote upon legislation banning FGM, public opinion in the country over the practice is more divided than ever. The practitioners of FGM are not taking the law seriously, while politicians hesitate to openly condemn the practice, which still occurs widely in rural zones. Most of the 140 parliamentarians do not believe that laws alone can successfully end FGM in Senegal. Some deputies and feminists believe that several years of sensitization on the issue will be needed to effectively reduce the frequency with which FGM is practiced. Only optimists believe FGM will disappear on its own. The debate threatens to resurface in some areas during the year 2000 presidential election. One deputy from the governing party, originally from southern Senegal, states that he dares not tell his constituency that the president himself created the anti-FGM legislation, especially when locally elected leaders finance villages¿ FGM-related celebrations. According to a scholar of the Koran, FGM is an Islamic practice, but it is not taught in the Koran. FGM is therefore a cultural practice borne from individual choice. In Kolda, 650 km south of Dakar, the practitioners of such mutilation argue that they would rather be imprisoned than abandon the practice they consider to be an immutable component of their cultural history. PMID:12296198

  11. The private-public literacy divide amid educational reform in Qatar: What does PISA tell us?

    Science.gov (United States)

    Cheema, Jehanzeb R.

    2015-03-01

    The education system in Qatar comprises of both private schools, which receive money through student fees, and public schools, which are fully government-funded. In the mid-2000s, Qatar started its transition towards an independent school model with the aim of eventually converting all public schools into government-supported independent schools. The idea was to give public schools more autonomy in terms of hiring decisions, adoption of curriculum and textbooks, and budget spending, enabling them to emulate some of the private schools' strategies for turning out successful students. This study examines evidence from the 2006-2012 administrations of the Program for International Student Assessment (PISA) in Qatar in order to evaluate whether or not recent educational reform efforts in this country have succeeded in bridging the literacy divide between private and public schools. The results, presented in a number of detailed tables and discussed in the last part of the article, indicate that there is a significant difference in key literacy skills between the two types of schools. Private schools were found to outperform their public counterparts in areas such as mathematics, reading and science, both before and after controlling for important student-level differences, and this gap has evidently persisted from 2006 to 2012.

  12. Extending the WSN lifetime by Dividing the Network Area into a Specific Zones

    Directory of Open Access Journals (Sweden)

    Mishall H. Awaad

    2015-01-01

    Full Text Available LEACH protocol is considered the best in the WSN protocols in extending the network lifetime and reduces energy loss, but LEACH suffers from the problem of the correct distribution of the nodes correlation with CHs. In this paper, we propose an improved protocol called LEACH-Z(LEACH zones, this protocol improves the distribution of clusters by making the clusters near the base station(BS large(greater number of nodes and the clusters are far from BS small(lesser number of nodes, where divides the network area to parts(zones, be part of a larger when close to the BS in addition to preventing the election of CHs in the region far from the BS and thus conserve energy this means that the nodes will remain alive as long as possible, this makes nodes gather more information. The results proved that the LEACH-Z is better than the original LEACH and more optimizations to reduce energy consumption.

  13. Factors Affecting Adolescents' Involvement in Cyberbullying: What Divides the 20% from the 80%?

    Science.gov (United States)

    Shin, Namin; Ahn, Hwasil

    2015-07-01

    Despite some variations among cyberbullying studies, about 20% of the youth population surveyed appears to be involved in cyberbullying. Coincidentally, the current study found that exactly 20% of the students surveyed were involved in cyberbullying as bullies (7.8%), victims (7.5%), and bully/victims (4.7%). What divides those 20% from the 80% of noninvolved students? This study aimed to produce a parsimonious and accurate model that can predict the occurrence of involvement in cyberbullying among youth. Data were collected from a questionnaire survey administered to 1,036 students enrolled in secondary schools in South Korea. Stepwise logistic regression (SLR) was carried out to predict the dichotomous dependent variable (involved/noninvolved) with 10 independent variables grouped into three categories: (a) demographic, (b) media-related, and (c) school and psychology factors. The result of the SLR analysis yielded a four-step model including the variables of cyber-confidence, weekday game time, mobile activities, and age as being significant in explaining the 20/80 division (model ?(2)=34.306, df=4, pcyberbullying than other students. In particular, the construct of cyber-confidence calls for further elaboration and research, given its controversial function with respect to adolescents' involvement in cyberbullying. Also, this study may bring about insights into practical considerations needed for concerned researchers, teachers, and parents to identify who is inside the group involved in cyberbullying so as to help the participating adolescents escape from the circle of cyberbullying. PMID:26167838

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

    Directory of Open Access Journals (Sweden)

    Yongchang Wang

    2009-11-01

    Full Text Available There have been substantial changes in the relationship between the PLA and the emerging private entrepreneurs since China’s reform and opening-up. As a consequence, these relations have shifted from the old model of political divide to a new model of social reconciliation, which could be described by four major indicators: recruiting policy, civil-military mutual support movement, the private sector’s engagement in military procurement and private employers’ participation in the reemployment of veterans. This paper compares the PLA’s ideological and policy changes between the 1979-1991 period and the period since 1992, and finds time lags exist between the PLA’s ideological progress and policy innovation, which results from the gap between the CCP’s intention and social opinion. The PLA under certain circumstances is encouraged by political and military leaders to promote its relationship with the new social stratum. Despite the achievements, value barriers, mutual distrust and new partnership challenges still remain serious obstacles. A complete legal system and new thoughts are essential for further development of their relationship.

  15. Ultrastructural alterations following X-ray and proton irradiation of dividing Chlamydomonas reinhardtii

    International Nuclear Information System (INIS)

    Light-dark synchronized Chlamydomonas reinhardtii are most sensitive to irradiation when exposed early in the dark period of a 12 hour light: 12 hour dark regime. At this time the algae are either dividing or preparing for division. Liquid cell cultures of the 137c wild type strain exposed to 9,000 R X-irradiation exhibit 69% mortality. Monolayer cultures on Millipore filters exposed to proton irradiation (1.5 MeV protons from a positive Van de Graff accelerator) exhibit 89% mortality following a dose of 9 kilorad, and 98% mortality following 18 kilorad. Ultrastructural examination of X-irradiated cells over five days following exposure documented chloroplast and nuclear alterations which included non-nuclear condensations, swollen and ruptured nuclear envelopes and disrupted pyrenoid structure. Following both types of irradiation, both live and dead daughter cells were present within the old mother cell wall. Following both types of irradiation, cells were also observed in which there were (1) profiles resembling division conformations, and (2) chromosomes and spindle fibers present at a time not characteristic for such events in synchronized control cultures. No changes distinct to either X-ray or proton irradiation were present, indicating that, after a given level of injury, similar ultrastructural manifestations of cell damage are evident in irradiated cells

  16. Hemispheric asymmetry of emotion words in a non-native mind: a divided visual field study.

    Science.gov (United States)

    Jo?czyk, Rafa?

    2015-05-01

    This study investigates hemispheric specialization for emotional words among proficient non-native speakers of English by means of the divided visual field paradigm. The motivation behind the study is to extend the monolingual hemifield research to the non-native context and see how emotion words are processed in a non-native mind. Sixty eight females participated in the study, all highly proficient in English. The stimuli comprised 12 positive nouns, 12 negative nouns, 12 non-emotional nouns and 36 pseudo-words. To examine the lateralization of emotion, stimuli were presented unilaterally in a random fashion for 180 ms in a go/no-go lexical decision task. The perceptual data showed a right hemispheric advantage for processing speed of negative words and a complementary role of the two hemispheres in the recognition accuracy of experimental stimuli. The data indicate that processing of emotion words in non-native language may require greater interhemispheric communication, but at the same time demonstrates a specific role of the right hemisphere in the processing of negative relative to positive valence. The results of the study are discussed in light of the methodological inconsistencies in the hemifield research as well as the non-native context in which the study was conducted. PMID:25300323

  17. Synthesis of finely divided molybdenum sulfide nanoparticles in propylene carbonate solution

    International Nuclear Information System (INIS)

    Molybdenum sulfide nanoparticles have been prepared from the reflux solution reaction involving ammonium heptamolybdate and elemental sulfur in propylene carbonate. Addition to the reaction mixture of starch as a natural capping agent leads to lesser agglomeration and smaller size of the particles. Nanoparticles of MoSx (x?4) of 10–30 nm size are highly divided and form stable colloidal suspensions in organic solvents. Mo K edge EXAFS of the amorphous materials shows rapid exchange of oxygen to sulfur in the molybdenum coordination sphere during the solution reaction. Thermal treatment of the amorphous sulfides MoSx under nitrogen or hydrogen flow at 400 °C allows obtaining mesoporous MoS2 materials with very high pore volume and specific surface area, up to 0.45 cm3/g and 190 m2/g, respectively. The new materials show good potential for the application as unsupported hydrotreating catalysts. - Graphical abstract: Solution reaction in propylene carbonate allows preparing weakly agglomerated molybdenum sulfide with particle size 20 nm and advantageous catalytic properties. - Highlights: • Solution reaction in propylene carbonate yields MoSx particles near 20 nm size. • Addition of starch as capping agent reduces particles size and hinder agglomeration. • EXAFS at Mo K edge shows rapid oxygen to sulfur exchange in the solution. • Thermal treatment leads to MoS2 with very high porosity and surface area

  18. A CRITICAL EVALUATION OF INDIAN GOVERNMENT’S STRATEGIES TO BRIDGE DIGITAL DIVIDE

    Directory of Open Access Journals (Sweden)

    Nityesh BHATT

    2006-01-01

    Full Text Available Emergence of Information and Communication Technology (ICT has been a landmark for India. In one way, this sunshine sector has been instrumental in the economic growth of country and has glorified its image in the whole world but on the other end, it has also created a digital divide in our society. BBC's Jill McGivering reports that the IT revolution is only changing some lives in the world's largest democracy. (Bagla,2005 A small section of society is harnessing it fully for their advantage while the masses are even not aware of it. UNESCO report 1998 also stated that for the majority of the world’s population, telephones are a technology beyond reach; food, sanitation and literacy are more urgent needs. How can we reconcile major commitments of energy and funds to ICTs when more basic human needs remain unfulfilled? The conventional, even formulaic, answer to the alleged conflict between investment in ICTs and investment in meeting basic human needs is, "We need to do both.There is no contradiction between ICTs and other critical human and social goals." (Keniston, 2002 ICT sector has potential of reviving the hopes and fortunes of these deprived and hatred section of society. Application of ICT in the form of E-Governance possess the potential to bridge the gulf between the urban 'technology haves' and rural ‘have nots', within and among the countries. (Annan, 2002

  19. Tackling the urban health divide though enabling intersectoral action on malnutrition in chile and kenya.

    Science.gov (United States)

    Pridmore, Pat; Carr-Hill, Roy; Amuyunzu-Nyamongo, Mary; Lang'o, Daniel; McCowan, Tristan; Charnes, Gabriela

    2015-04-01

    As momentum grows for a sustainable urbanisation goal in the post-2015 development agenda, this paper reports on an action research study that sought to tackle the urban health divide by enabling intersectoral action on social determinants at the local level. The study was located in the cities of Mombasa in Kenya and Valparaíso in Chile, and the impact of the intervention on child nutrition was evaluated using a controlled design. The findings showed that an action research process using the social educational process known as PLA could effectively build the capacity of multisectoral teams to take coordinated action which in turn built the capacity of communities to sustain them. The impact on child nutrition was inconclusive and needed to be interpreted within the context of economic collapse in the intervention area. Four factors were found to have been crucial for creating the enabling environment for effective intersectoral action (i) supportive government policy (ii) broad participation and capacity building (iii) involving policy makers as advisors and establishing the credibility of the research and (iii) strengthening community action. If lessons learned from this study can be adapted and applied in other contexts then they could have a significant economic and societal impact on health and nutrition equity in informal urban settlements. PMID:25758598

  20. Dividing the Force Concept Inventory into two equivalent half-length tests

    Science.gov (United States)

    Han, Jing; Bao, Lei; Chen, Li; Cai, Tianfang; Pi, Yuan; Zhou, Shaona; Tu, Yan; Koenig, Kathleen

    2015-06-01

    The Force Concept Inventory (FCI) is a 30-question multiple-choice assessment that has been a building block for much of the physics education research done today. In practice, there are often concerns regarding the length of the test and possible test-retest effects. Since many studies in the literature use the mean score of the FCI as the primary variable, it would be useful then to have different shorter tests that can produce FCI-equivalent scores while providing the benefits of being quicker to administer and overcoming the test-retest effects. In this study, we divide the 1995 version of the FCI into two half-length tests; each contains a different subset of the original FCI questions. The two new tests are shorter, still cover the same set of concepts, and produce mean scores equivalent to those of the FCI. Using a large quantitative data set collected at a large midwestern university, we statistically compare the assessment features of the two half-length tests and the full-length FCI. The results show that the mean error of equivalent scores between any two of the three tests is within 3%. Scores from all tests are well correlated. Based on the analysis, it appears that the two half-length tests can be a viable option for score based assessment that need to administer tests quickly or need to measure short-term gains where using identical pre- and post-test questions is a concern.

  1. Interactive quantum chemistry: a divide-and-conquer ASED-MO method.

    Science.gov (United States)

    Bosson, Mäel; Richard, Caroline; Plet, Antoine; Grudinin, Sergei; Redon, Stephane

    2012-03-15

    We present interactive quantum chemistry simulation at the atom superposition and electron delocalization molecular orbital (ASED-MO) level of theory. Our method is based on the divide-and-conquer (D&C) approach, which we show is accurate and efficient for this non-self-consistent semiempirical theory. The method has a linear complexity in the number of atoms, scales well with the number of cores, and has a small prefactor. The time cost is completely controllable, as all steps are performed with direct algorithms, i.e., no iterative schemes are used. We discuss the errors induced by the D&C approach, first empirically on a few examples, and then via a theoretical study of two toy models that can be analytically solved for any number of atoms. Thanks to the precision and speed of the D&C approach, we are able to demonstrate interactive quantum chemistry simulations for systems up to a few hundred atoms on a current multicore desktop computer. When drawing and editing molecular systems, interactive simulations provide immediate, intuitive feedback on chemical structures. As the number of cores on personal computers increases, and larger and larger systems can be dealt with, we believe such interactive simulations-even at lower levels of theory-should thus prove most useful to effectively understand, design and prototype molecules, devices and materials. PMID:22228556

  2. Digital Divides and the 'First Mile': Framing First Nations Broadband Development in Canada

    Directory of Open Access Journals (Sweden)

    Rob McMahon

    2011-05-01

    Full Text Available Across Canada, rural and remote First Nations face a significant 'digital divide'. As self-determining autonomous nations in Canada, these communities are building broadband systems to deliver public services to their members and residents. To address this challenge, First Nations are working towards a variety of innovative, locally driven broadband development initiatives. This paper contributes a theoretical discussion that frames our understanding of these initiatives by drawing on the paradigm of the 'First Mile' (Paisley & Richardson, 1998. We argue that broadband development policy in Canada must be re-framed to address the specific needs of First Nations. The First Mile position foregrounds community-based involvement, control, and ownership: a consideration we suggest has particular resonance for First Nations. This is because it holds potential to move beyond the historical context of paternalistic, colonial-derived development policies, in the context of broadband systems development. We argue First Nations broadband projects offer on-the-ground examples of a First Mile approach, and call for more research in this area.

  3. Effects of Auditory Translation Priming under Divided Attention in Unbalanced Persian-English Bilinguals

    Directory of Open Access Journals (Sweden)

    Saeedeh Shafiee Nahrkhalaji

    2014-10-01

    Full Text Available In bilingual studies, repetition priming across languages or translation priming can be used to examine themental representations of bilingual lexicon and language in memory. Motivated to demonstrate the effects ofdividing attention during implicit retrieval of L2 spoken words, we investigated the nature of the processesinvolved in translation priming. In so doing, we used behavioral measures (i.e. reaction time and accuracy tostudy 60 Persian-English unbalanced proficient bilinguals performing translation priming in two languagedirections under two attention conditions. The present study compared a divided attention (DA condition, inwhich participants carried out the priming task in auditory modality while simultaneously performing asecondary task in visual modality, and a full attention (FA condition, in which participants performed only thepriming task. We also examined secondary tasks costs produced by memory tests. Despite significant primingeffects and symmetrical pattern of translation priming in the FA condition, translation priming effects in L2-to-L1direction were absent in the DA condition. The secondary task was disrupted by memory test in this direction aswell. The paper ends with discussion on the role of attention in L2 spoken word processing and languagedirection in translation priming in light of models of bilingual memory.

  4. A Continent-Wide Migratory Divide in North American Breeding Barn Swallows (Hirundo rustica).

    Science.gov (United States)

    Hobson, Keith A; Kardynal, Kevin J; Van Wilgenburg, Steven L; Albrecht, Gretchen; Salvadori, Antonio; Cadman, Michael D; Liechti, Felix; Fox, James W

    2015-01-01

    Populations of most North American aerial insectivores have undergone steep population declines over the past 40 years but the relative importance of factors operating on breeding, wintering, or stopover sites remains unknown. We used archival light-level geolocators to track the phenology, movements and winter locations of barn swallows (Hirdundo rustica; n = 27) from populations across North America to determine their migratory connectivity. We identified an east-west continental migratory divide for barn swallows with birds from western regions (Washington State, USA (n = 8) and Saskatchewan, Canada (n = 5)) traveling shorter distances to wintering areas ranging from Oregon to northern Colombia than eastern populations (Ontario (n = 3) and New Brunswick (n = 10), Canada) which wintered in South America south of the Amazon basin. A single swallow from a stable population in Alabama shared a similar migration route to eastern barn swallows but wintered farther north in northeast Brazil indicating a potential leap frog pattern migratory among eastern birds. Six of 9 (67%) birds from the two eastern populations and Alabama underwent a loop migration west of fall migration routes including around the Gulf of Mexico travelling a mean of 2,224 km and 722 km longer on spring migration, respectively. Longer migration distances, including the requirement to cross the Caribbean Sea and Gulf of Mexico and subsequent shorter sedentary wintering periods, may exacerbate declines for populations breeding in northeastern North America. PMID:26065914

  5. Stability analysis of the self-phase-locked divide-by-2 optical parametric oscillator

    International Nuclear Information System (INIS)

    The properties of all-optical phase-coherent frequency division by 2, based on a self-phase-locked continuous-wave (cw) optical parametric oscillator (OPO), are investigated theoretically. The coupled field equations of an OPO with intracavity quarter-wave plate are solved analytically in steady-state, yielding a condition for self-phase-locked operation. In the self-phase-locked state, two different values for the pump power at threshold are obtained. By using a linear stability analysis, it is proven that only the lower threshold value is stable, whereas the higher threshold value is unstable. The analytical investigations of the steady-state field values further reveal a twofold symmetry in phase space. The theoretical consideration is completed by a numerical analysis based on the integration of the envelopes of the three OPO fields, which allows for studying the temporal evolution of different initial values. The numerical investigation of the OPO subharmonic phases shows that the two-phase eigenstates are equivalent with respect to experimental parameters and are assumed by the self-phase-locked OPO in dependence of the initial phases of the subharmonic fields, dividing phase space into two symmetric basins of attraction

  6. A Sub-band Divided Ray Tracing Algorithm Using the DPS Subspace in UWB Indoor Scenarios

    DEFF Research Database (Denmark)

    Gan, Mingming; Xu, Zhinan

    2015-01-01

    Sub-band divided ray tracing (SDRT) is one technique that has been extensively used to obtain the channel characteristics for ultra-wideband (UWB) radio wave propagation in realistic indoor environments. However, the computational complexity of SDRT scales directly with the number of sub-bands. Although we have proposed a low-complexity SDRT algorithm for one terminal position [1], the computational complexity i s still extremely high when involving multiple mobile terminal positions. Moreover, some indoor positioning techniques require for high positioning accuracy data from measurements/simulations with a very fine spatial resolution. To cope with this, we propose an algorithm to reduce the computational complexity of SDRT for multiple mobile terminal positions. The algorithm uses a projection of all propagation paths on a subspace spanned by two-dimensional discrete prolate spheroidal (DPS) sequences at each sub-band. It is important to note that, since the geometrical information of the propagation paths is the same in all sub-bands, the subspace dimension and basis coefficients in frequency dimension do not need to be recalculated at different sub-bands. We justify the simplifications of the proposed method by numerical simulations. Furthermore, we evaluate the effect of antenna characteristics on the proposed algorithm. Our proposed algorithm reduces the computational complexity by more than one order of magnitude for indoor scenarios.

  7. Evaluation of copper for divider subassembly in MCO Mark IA and Mark IV scrap fuel baskets

    International Nuclear Information System (INIS)

    The K Basin Spent Nuclear Fuel (SNF) Project Multi-Canister Overpack (MCO) subprojection eludes the design and fabrication of a canister that will be used to confine, contain, and maintain fuel in a critically safe array to enable its removal from the K Basins, vacuum drying, transport, staging, hot conditioning, and interim storage (Goldinann 1997). Each MCO consists of a shell, shield plug, fuel baskets (Mark IA or Mark IV), and other incidental equipment. The Mark IA intact and scrap fuel baskets are a safety class item for criticality control and components necessary for criticality control will be constructed from 304L stainless steel. It is proposed that a copper divider subassembly be used in both Mark IA and Mark IV scrap baskets to increase the safety basis margin during cold vacuum drying. The use of copper would increase the heat conducted away from hot areas in the baskets out to the wall of the MCO by both radiative and conductive heat transfer means. Thus copper subassembly will likely be a safety significant component of the scrap fuel baskets. This report examines the structural, cost and corrosion consequences associated with using a copper subassembly in the stainless steel MCO scrap fuel baskets

  8. An Efficient Similarity Digests Database Lookup - A Logarithmic Divide & Conquer Approach

    Directory of Open Access Journals (Sweden)

    Frank Breitinger

    2014-09-01

    Full Text Available Investigating seized devices within digital forensics represents a challenging task due to the increasing amount of data. Common procedures utilize automated file identification, which reduces the amount of data an investigator has to examine manually. In the past years the research field of approximate matching arises to detect similar data. However, if n denotes the number of similarity digests in a database, then the lookup for a single similarity digest is of complexity of O(n. This paper presents a concept to extend existing approximate matching algorithms, which reduces the lookup complexity from O(n to O(log(n. Our proposed approach is based on the well-known divide and conquer paradigm and builds a Bloom filter-based tree data structure in order to enable an efficient lookup of similarity digests. Further, it is demonstrated that the presented technique is highly scalable operating a trade-off between storage requirements and computational efficiency. We perform a theoretical assessment based on recently published results and reasonable magnitudes of input data, and show that the complexity reduction achieved by the proposed technique yields a 220-fold acceleration of look-up costs.

  9. Hydrophobins from Aspergillus species cannot be clearly divided into two classes

    Directory of Open Access Journals (Sweden)

    Søndergaard Ib

    2010-12-01

    Full Text Available Abstract Background Hydrophobins are a family of small secreted proteins with a characteristic pattern of eight cysteine residues found exclusively in filamentous fungi. They have originally been divided into two classes based on their physical properties and hydropathy patterns, and are involved in the attachment of hyphae to hydrophobic structures, the formation of aerial structures and appear to be involved in pathogenicity. Findings Analysis of nine genome sequences from seven Aspergilli revealed fifty hydrophobins, where each species displayed between two to eight hydrophobins. Twenty of the identified hydrophobins have not previously been described from these species. Apart from the cysteines, very little amino acid sequence homology was observed. Twenty-three of the identified hydrophobins could be classified as class I hydrophobins based on their conserved cysteine spacing pattern and hydropathy pattern. However twenty-six of the identified hydrophobins were intermediate forms. Notably, a single hydrophobin, ATEG_04730, from Aspergillus terreus displayed class II cysteine spacing and had a class II hydropathy pattern. Conclusion Fifty hydrophobins were identified in Aspergillus, all containing the characteristic eight cysteine pattern. Aspergillus terreus exhibited both class I and class II hydrophobins. This is the first report of an Aspergillus species with the potential to express both class I and class II hydrophobins. Many of the identified hydrophobins could not directly be allocated to either class I or class II.

  10. Bridging the Divide between Safety and Risk Management for your Project or Program

    Science.gov (United States)

    Lutomski, Mike

    2005-01-01

    This presentation will bridge the divide between these separate but overlapping disciplines and help explain how to use Risk Management as an effective management decision support tool that includes safety. Risk Management is an over arching communication tool used by management to prioritize and effectively mitigate potential problems before they concur. Risk Management encompasses every kind of potential problem that can occur on a program or project. Some of these are safety issues such as hazards that have a specific likelihood and consequence that need to be controlled and included to show an integrated picture of accepted) mitigated, and residual risk. Integrating safety and other assurance disciplines is paramount to accurately representing a program s or projects risk posture. Risk is made up of several components such as technical) cost, schedule, or supportability. Safety should also be a consideration for every risk. The safety component can also have an impact on the technical, cost, and schedule aspect of a given risk. The current formats used for communication of safety and risk issues are not consistent or integrated. The presentation will explore the history of these disciplines, current work to integrate them, and suggestions for integration for the future.

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

    Directory of Open Access Journals (Sweden)

    Katie Brown

    2011-05-01

    Full Text Available 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 general and teen citizenship in particular. Yet the cost of this move toward equal access is absorbed by those who can least afford it: Teenagers from low income households. Using survey and focus group data from a national study of “Teens and Mobile Phone Use” (released by Pew and the University of Michigan in 2010, this article helps identify and explain this and other emergent trends for teen use (as well as non-use of the internet through mobile phones.

  12. Our Divided World: Poverty, Hunger & Overpopulation. Our Only Earth Series. A Curriculum for Global Problem Solving.

    Science.gov (United States)

    McKisson, Micki; MacRae-Campbell, Linda

    Both humanity and nature have suffered greatly from human insensitivity. Not only are the natural resources of the earth being depleted and its air, land and water polluted, the financial resources of humanity are being wasted on destructive expenditures. The "Our Only Earth" series is an integrated science, language arts, and social studies…

  13. European freshwater VHSV genotype Ia isolates divide into two distinct subpopulations

    DEFF Research Database (Denmark)

    Kahns, SØren; Skall, Helle Frank

    2012-01-01

    Viral haemorrhagic septicaemia (VHS), caused by the novirhabdovirus VHSV, often leads to significant economic losses to European rainbow trout production. The virus isolates are divided into 4 distinct genotypes with additional subgroups including sublineage Ia, isolates of which are the main source of outbreaks in European rainbow trout farming. A significant portion of Danish rainbow trout farms have been considered endemically infected with VHSV since the first disease outbreak was observed in the 1950s. However, following a series of sanitary programs starting in 1965, VHSV has not been detected in Denmark since January 2009. Full-length G-genes of all Danish VHSV isolates that were submitted for diagnostic analyses in the period 2004?2009 were sequenced and analysed. All 58 Danish isolates from rainbow trout grouped with sublineage Ia isolates. Furthermore, VHSV isolates from infected Danish freshwater catchments appear to have evolved into a distinct clade within sublineage Ia, herein designated clade Ia-1, whereas trout isolates originating from other continental European countries cluster in another distinct clade, designated clade Ia-2. In addition, phylogenetic analyses indicate that VHSV Ia-1 strains have caused a few outbreaks in Germany and the UK. It is likely that viruses have been transmitted from infected site(s) out of the Danish environment, although a direct transmission pathway has not been identified. Furthermore, VHSV Ia-2 isolates seem to have been transmitted to Denmark at least once. Interestingly, one viral isolate possibly persisted in a Danish watershed for nearly 4 yr without detection whereas other subclades of VHSV isolates appear to have been eliminated, probably because of implemented eradication procedures.

  14. Select-divide-and-conquer method for large-scale configuration interaction

    Science.gov (United States)

    Bunge, Carlos F.; Carbó-Dorca, Ramon

    2006-07-01

    A select-divide-and-conquer variational method to approximate configuration interaction (CI) is presented. Given an orthonormal set made up of occupied orbitals (Hartree-Fock or similar) and suitable correlation orbitals (natural or localized orbitals), a large N-electron target space S is split into subspaces S0,S1,S2,…,SR. S0, of dimension d0, contains all configurations K with attributes (energy contributions, etc.) above thresholds T0?{T0egy,T0etc.}; the CI coefficients in S0 remain always free to vary. S1 accommodates Ks with attributes above T1?T0. An eigenproblem of dimension d0+d1 for S0+S1 is solved first, after which the last d1 rows and columns are contracted into a single row and column, thus freezing the last d1 CI coefficients hereinafter. The process is repeated with successive Sj(j ?2) chosen so that corresponding CI matrices fit random access memory (RAM). Davidson's eigensolver is used R times. The final energy eigenvalue (lowest or excited one) is always above the corresponding exact eigenvalue in S. Threshold values {Tj;j=0,1,2,…,R} regulate accuracy; for large-dimensional S, high accuracy requires S0+S1 to be solved outside RAM. From there on, however, usually a few Davidson iterations in RAM are needed for each step, so that Hamiltonian matrix-element evaluation becomes rate determining. One ?hartree accuracy is achieved for an eigenproblem of order 24×106, involving 1.2×1012 nonzero matrix elements, and 8.4×109 Slater determinants.

  15. Feature-based attentional modulation increases with stimulus separation in divided-attention tasks.

    Science.gov (United States)

    Sally, Sharon L; Vidnyánsky, Zoltán; Papathomas, Thomas V

    2009-01-01

    Attention modifies our visual experience by selecting certain aspects of a scene for further processing. It is therefore important to understand factors that govern the deployment of selective attention over the visual field. Both location and feature-specific mechanisms of attention have been identified and their modulatory effects can interact at a neural level (Treue and Martinez-Trujillo, 1999). The effects of spatial parameters on feature-based attentional modulation were examined for the feature dimensions of orientation, motion and color using three divided-attention tasks. Subjects performed concurrent discriminations of two briefly presented targets (Gabor patches) to the left and right of a central fixation point at eccentricities of +/-2.5 degrees , 5 degrees , 10 degrees and 15 degrees in the horizontal plane. Gabors were size-scaled to maintain consistent single-task performance across eccentricities. For all feature dimensions, the data show a linear increase in the attentional effects with target separation. In a control experiment, Gabors were presented on an isoeccentric viewing arc at 10 degrees and 15 degrees at the closest spatial separation (+/-2.5 degrees ) of the main experiment. Under these conditions, the effects of feature-based attentional effects were largely eliminated. Our results are consistent with the hypothesis that feature-based attention prioritizes the processing of attended features. Feature-based attentional mechanisms may have helped direct the attentional focus to the appropriate target locations at greater separations, whereas similar assistance may not have been necessary at closer target spacings. The results of the present study specify conditions under which dual-task performance benefits from sharing similar target features and may therefore help elucidate the processes by which feature-based attention operates. PMID:19891852

  16. Bridging the Partisan Divide Over Climate Change: Messenger is as Important as the Message

    Science.gov (United States)

    Cater, M.

    2014-12-01

    In the United States, fewer than one-third of Republicans believe that climate change is driven significantly by burning fossil fuels. This despite unprecedented worldwide scientific consensus that it is. Over 13,000 peer reviewed scientific papers affirm it. Twenty-four deny it. Yet the Republican "disbelief" persists in part because of ideological bubbles that, according to analysis by the Marquette Law School, are deeper and more geographically based than ever before. More and more Americans are living in politically one-sided counties, with 51% of voters in the 2012 presidential race living in a county that was "partisan" - or 10 points redder or bluer than the U.S. as a whole. One in five lived in a county that was "extreme" - or 20 points redder or bluer than the country. With mainstream media contracting, opinion media exploding and the Internet increasingly giving us only what we want to hear, ideological bubbles are becoming more isolated and insulated than ever. Dan Kahan at Yale has discovered that these bubbles - the values and groups that hold them - have a greater impact on our perception of certain issues than scientific understanding. In fact, the more individuals become scientifically literate, the more they tend to use that information to confirm the view of their group. So the more conservative and more knowledgeable you are about climate change, the less convinced you will be that it is a problem. Countless scientific studies confirm people rely on those they trust. And conversely, they reject information coming from those they do not. To bridge the partisan divide, and break the ideological barriers to climate science, trusted leaders within conservative circles must engage and speak out. The conservative leaders I work with have transcended their ideological boundaries, understand the science largely because they have learned from people they trust, recognize the risk and have identified solutions that protect their conservative values.

  17. Treatment of local recurrent breast cancer by divided dose electron beam radiation twice a week

    International Nuclear Information System (INIS)

    The objectives of this study were to investigate the effects of divided dose electron beam radiation twice a week (with a focal dose of 600 rads at a time) on local recurrent tumors of postoperative breast cancer and to compare it with the conventional photon radiation in the hope that it might be better tolerated by the patients, with less damage to normal skin and lung tissues. Out of 261 patients with breast cancer who came to the Department of Radiology, at Gunma Univ. Hospital, Maebashi, during the period Jan., 1970, through Jun., 1976, 41 patients who received electron beam radiation for local recurrence (in 81 sites) and 31 who received prophylactic radiation over the chest wall postoperatively. Tumors completely disappeared from 73 out of 81 sites irradiated for local recurrence (accounting 90% of the 81 sites). The local recurrent lesions were classified to the ''disseminated'' and the ''focal'' type to compare the effects of the radiation, and it was found that the radiation eliminated the tumors from all (100%) of the 63 sites of the former type, while the radiation was capable of eliminating the tumors from only 10 out of the 18 sites of the latter type (56%). When the focal type tumors were classified by histopathologic typing to compare the effects of the radiation, the radiation was assessed effective in papillotubular carcinoma, medullary tubular carcinoma and scirrhous carcinoma in the decreasing sequence of significance. Pulmonary disorders occurred ignificance. Pulmonary disorders occurred in 12% of all the observed sites. However, it is possible to further reduce this incidence by the adequate use of the tissue compensating filter, Mix-R. A skin disorder (erosion) was observed in 59% of all the sites observed. However, it may be anticipated that the topical application of a suitable corticoid (Beta-methasone-17-valerate cream) preparation will by prophylactically effective. (auth.)

  18. A Socially-Just Internet: The Digital Divide, Cybercultural Agency, and Human Capabilities

    Directory of Open Access Journals (Sweden)

    David Toews

    2009-01-01

    Full Text Available This article argues that while modes of scholarship stressing structural insights into the digital divide and ethnographic insights into online communities each give us important information about current uses of the internet, for the sake of a unified social justice principle it is necessary to interpret these forms of knowledge in terms of what could be. Marx’s formula ‘the development of each as a condition for the development of all’ is put forward as the principle of a socially-just internet actualized from the ground up. It is argued that the most rapidly emerging and important form of constraint upon ‘the development of each’ is the for profit online social media industry in which moments of human communicative creativity become packaged as commodities for commercial purposes. Creative, cultural agency becomes an imposition rather than a liberation as represented in the industry ideology. It is argued therefore that groups that use the internet for serious play – the use of avatars in virtual worlds is discussed as an example – present us with a form of online subjectivity that is rising in importance as a form of cultural agency inasmuch as the play component is premised upon the rejection of pre-packaged forms of agency. Support for a socially-just internet would thus mean supporting the online communities formed in this process. Thus the argument is put forward that the importance of serious online play groups is not due to their potential for forming communities per se but is rather due to their potential for resisting the imposition of agency. Inasmuch as online communities in the midst of such groups can bolster that goal, they can represent the development of human capabilities in a way that expands the theme of social justice.

  19. Appraisal of the tight sands potential of the Sand Wash and Great Divide Basins

    International Nuclear Information System (INIS)

    The volume of future tight gas reserve additions is difficult to estimate because of uncertainties in the characterization and extent of the resource and the performance and cost-effectiveness of stimulation and production technologies. Ongoing R ampersand D by industry and government aims to reduce the risks and costs of producing these tight resources, increase the certainty of knowledge of their geologic characteristics and extent, and increase the efficiency of production technologies. Some basins expected to contain large volumes of tight gas are being evaluated as to their potential contribution to domestic gas supplies. This report describes the results of one such appraisal. This analysis addresses the tight portions of the Eastern Greater Green River Basin (Sand Wash and Great Divide Subbasins in Northwestern Colorado and Southwestern Wyoming, respectively), with respect to estimated gas-in-place, technical recovery, and potential reserves. Geological data were compiled from public and proprietary sources. The study estimated gas-in-place in significant (greater than 10 feet net sand thickness) tight sand intervals for six distinct vertical and 21 areal units of analysis. These units of analysis represent tight gas potential outside current areas of development. For each unit of analysis, a ''typical'' well was modeled to represent the costs, recovery and economics of near-term drilling prospects in that unit. Technically recoverable gas was calculated using reservoir properties and assumptions about current formation evaluation and extraction technology performance. Basin-specific capital and operating costs were incorporated along with taxes, royalties and current regulations to estimate the minimum required wellhead gas price required to make the typical well in each of unit of analysis economic

  20. Detection of Abnormal Masses using Divide and Conquer Algorithmin Digital Mammogram

    Directory of Open Access Journals (Sweden)

    Indra Kanta Maitra

    2011-12-01

    Full Text Available Many image processing techniques have been developed over the past two decades to help radiologists in diagnosing breast cancer. Most studies conducted have proven that an early diagnosis of breast cancer can increase the survival rate, thus making screening programmes a mandatory step for females. Digital Mammogram has emerged as the most popular screening technique for Breast Cancer detection. Raw digital mammograms are medical images that are difficult to interpret. Computer Aided Diagnosissystems (CAD improves abnormality detection in mammogram images. Extracting the region within the breast is done bydemarcation of the breast contour and pectoral muscle. This limits the search for abnormal regionsonly within the breast region by eliminating the background of the mammogram. In this paper we submit a fully automated process for detection of abnormal masses by using anatomical segmentation of Breast Region of Interest (ROI. We have formulated a new homogeneity enhancement algorithm namely Divide and Conquer Homogeneity Enhancement Algorithm (DCHEA, followed by an innovative approach for edge detection (EDA. We obtain the breast boundary by using our proposed Breast Boundary Detection Algorithm (BBDA. After we use our proposed Pectoral Muscle Detection Algorithm (PMDA to suppress the pectoral muscle we obtain breast ROI, we use our proposed Anatomical Segmentation of Breast ROI (ASB algorithm to differentiate various regions within the breast. After segregating the different breast regions we use our proposed Seeded Region Growing Algorithm (SRGA to isolate normal and abnormal regions in the breast tissue. The algorithms proposed are fully autonomous, and are able to isolate different types of abnormalities, if present, a task very few existing mammogram segmentation algorithms can claim. This algorithm has shown significant improvement over our previously proposed Binary Homogeneity Enhancement Algorithm.