1,777 research outputs found

    Geometric Aspects of Composite Pulses

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    Unitary operations acting on a quantum system must be robust against systematic errors in control parameters for reliable quantum computing. Composite pulse technique in nuclear magnetic resonance (NMR) realises such a robust operation by employing a sequence of possibly poor quality pulses. In this article, we demonstrate that two kinds of composite pulses, one compensates for a pulse length error in a one-qubit system and the other compensates for a J-coupling error in a twoqubit system, have vanishing dynamical phase and thereby can be seen as geometric quantum gates, which implement unitary gates by the holonomy associated with dynamics of cyclic vectors defined in the text.Comment: 20 pages, 4 figures. Accepted for publication in Philosophical Transactions of the Royal Society

    Erosion Control Along Transportation Routes in Northern Climates

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    The widespread occurrence of permafrost in northern climates dictates the use of specialized measures to protect the terrain from adverse impacts associated with the construction of transportation facilities. Through the adoption of appropriate construction techniques and by providing proper drainage and erosion control facilities within the right-of-way, serious environmental degradation can be avoided. The most appropriate type of erosion control measure is selected according to local terrain and drainage conditions, including a Soil Erosion Code (SEC). Erosion control begins with the provision of effective drainage across the right-of-way. Typical erosion control measures include the use of permanent linings such as granular blankets, rock riprap and gabions and temporary linings, such as plastic sheets and fiberglass rovings. Ditch checks, rock aprons, energy dissipators and siltation basins may be used to minimize erosion of exposed soils along the route and attendant siltation of streams. Cut slopes may be protected with insulation in ice-rich, fine-grained soils to ensure stability and prevent slump material from reaching the drainage system. Ultimately, long-term erosion protection along transportation corridors is provided through appropriate revegetation techniques, periodic surveillance and regular maintenance of drainage and erosion control facilities.Key words: erosion, erosion control, permafrost engineering, revegetation, transportation corridor

    Designing Robust Unitary Gates: Application to Concatenated Composite Pulse

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    We propose a simple formalism to design unitary gates robust against given systematic errors. This formalism generalizes our previous observation [Y. Kondo and M. Bando, J. Phys. Soc. Jpn. 80, 054002 (2011)] that vanishing dynamical phase in some composite gates is essential to suppress amplitude errors. By employing our formalism, we naturally derive a new composite unitary gate which can be seen as a concatenation of two known composite unitary operations. The obtained unitary gate has high fidelity over a wider range of the error strengths compared to existing composite gates.Comment: 7 pages, 4 figures. Major revision: improved presentation in Sec. 3, references and appendix adde

    Handedness and schizotypy in a Japanese sample: an association masked by cultural effects on hand usage

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    Previous research has shown a robust association between schizotypy and mixed/ambiguous-handedness, but little is known about the universality of this relationship outside Western cultures. The present paper examines this issue in a sample of 413 Japanese students administered (in Japan) the Annett handedness questionnaire and a schizotypy scale (STA). Conventional analyses of current hand preference, using several indices derived from the Annett scale, mostly failed to replicate previous findings. However, there was a significant tendency for greater use of either hand in highly schizotypal males. Furthermore, a significant association between schizotypy and non-right-handedness was found—again only in males—after correcting for the effects of early switching of hand usage, presumed to be due to cultural pressure against left-handedness in Japanese society. These results were found to be highly convergent with findings previously reported for clinical schizophrenia

    Guidelines for Measuring Air Infiltration Heat Exchange Effectiveness (IHEE), Submitted to the Texas Higher Education Coordination Board Energy Research Application Program Project #227

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    This report presents three methods of measuring the air infiltration heat recovery in buildings. The blower door method estimates the air infiltration heat recovery using a test which takes less than one hour, and gives information to the contractors making retrofit decisions. The co-heating method identifies the relationship between the infiltration heat recovery and the air flow rate using two or three nights of testing. This method has higher accuracy than the blower door method and is suitable for use by both contractors and researchers. Finally, the STAM (short term average method) investigates the relationship between air infiltration heat recovery and air flow rate, air flow direction, and solar radiation. This is a comprehensive method which is most suitable for use by researchers.This report is presented to the Texas Higher Education Coordination Board as a deliverable under the Energy Research and Applications Program Project #227, which targeted reducing the design size of HVAC systems in houses since the actual air infiltration energy consumption is less than the design values due to air infiltration heat recovery in house components

    The Measured Energy Impact of Infiltration in an Outdoor Test Cell

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    The energy consumption calculation of house envelopes assumes that conduction heat loss is independent on air infiltration heat loss, and that energy consumption is the sum of these losses. Anderlind [1985], Liu [1987], and Claridge et at. [1989] showed this method can overestimate energy consumption substantially under steady-state conditions. Bailly [1987] and Anderson [1987] reported much smaller house energy consumption when the air flow was organized by mechanical systems. However, none of these studies quantified energy loss reduction under a variety of outdoor weather conditions. The energy performance was investigated in an outdoor test cell with different leakage configurations and air flow rates under both infiltration and exfiltration. It was found that the energy consumption was not only dependent on air flow rate, temperature differences, and solar radiation, but also on the air flow direction and the air leakage configuration. Infiltration could lead to a much lower heating energy consumption than that of exfiltration, and exfiltration could lead to a much lower cooling energy consumption than that of infiltration. The air infiltration energy consumption of a leaky house could be 9 times as high as that of a tight house even when the air flow rate was the same for both houses

    Potential Operation and Maintenance (O&M) Savings in the John Sealy North Building at UTMB

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    The LoanSTAR Monitoring and Analysis Group, Energy Systems Laboratory at Texas A&M University, was requested by University of Texas Medical Branch at Galveston to investigate O&M measures in their five LoanSTAR program buildings. This report describes the suggested O&Ms in John Sealy North Building, a surgical building of 54,494 ft2,which currently spends 502,100 per year on electricity, steam and chilled water. The suggested O&Ms include optimizing the outside air treatment cold deck reset schedule, the cold deck reset schedule and the hot deck reset schedule. These optimized HVAC operation schedules were determined using an analysis involving a simplified HVAC model, which was calibrated against daily data measured by the LoanSTAR program. It is estimated that annual savings of 67,000, or 13% of the annual costs, can be realized using the optimized operation schedules which can be implemented without additional costs. Our analysis indicates that the room comfort levels will not be degraded by these measures
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