5,741 research outputs found
Analysis of a solar collector field water flow network
A number of methods are presented for minimizing the water flow variation in the solar collector field for the Solar Building Test Facility at the Langley Research Center. The solar collector field investigated consisted of collector panels connected in parallel between inlet and exit collector manifolds to form 12 rows. The rows were in turn connected in parallel between the main inlet and exit field manifolds to complete the field. The various solutions considered included various size manifolds, manifold area change, different locations for the inlets and exits to the manifolds, and orifices or flow control valves. Calculations showed that flow variations of less than 5 percent were obtainable both inside a row between solar collector panels and between various rows
Gypsy moth defoliation assessment: Forest defoliation in detectable from satellite imagery
The author has identified the following significant results. ERTS-1 imagery obtained over eastern Pennsylvania during July 1973, indicates that forest defoliation is detectable from satellite imagery and correlates well with aerial visual survey data. It now appears that two damage classes (heavy and moderate-light) and areas of no visible defoliation can be detected and mapped from properly prepared false composite imagery. In areas where maple is the dominant species or in areas of small woodlots interspersed with agricultural areas, detection and subsequent mapping is more difficult
DEVELOPMENT OF A TL-3 F-SHAPE TEMPORARY CONCRETE MEDIAN BARRIER
A temporary concrete median barrier (CMB) was designed and tested for compliance under the Test Level 3 (TL-3) guidelines specified in the Recommended Procedures for the Safety Performance Evaluation of Highway Features, National Cooperative Highway Research Program (NCHRP) Report No. 350. The barrier is built to the new metric standards and has a traditional pin and loop configuration for interconnection. The objective of this research project was to develop and evaluate a standardized, temporary concrete barrier design while addressing the concerns for safety, economy, structural integrity, constructability, ease of installation, and maintenance. The resulting F-shape barrier segment is 3,800-mm long, a length that reduced the number of connections while limiting the weight of the barriers to ease handling. Full-scale crash testing demonstrated several critical design features. First, the connections need to be tight initially as practicable to limit deformation and rotation of the barriers,. Secondly, the pin needs to restrain the longitudinal barrier forces. Full-scale compliance testing of the final design demonstrated that the barrier was capable of successfully redirecting the 2000-kg vehicle. The vehicle demonstrated significant roll after contact with the barrier, which is evidenced in a majority of other concrete barrier tests. This barrier provides economical work zone protection applicable in a variety of situations, where TL-3 test criteria is warranted
Schramm-Loewner Equations Driven by Symmetric Stable Processes
We consider shape, size and regularity of the hulls of the chordal
Schramm-Loewner evolution driven by a symmetric alpha-stable process. We obtain
derivative estimates, show that the complements of the hulls are Hoelder
domains, prove that the hulls have Hausdorff dimension 1, and show that the
trace is right-continuous with left limits almost surely.Comment: 22 pages, 4 figure
Perceptions of Illegitimate Power in IT Projects
When IT projects are initiated because of personal benefits then the initiator acts contrary the legitimate power of their organisational position. Due to their expertise and technical knowledge, IT managers may believe that during the initiation of an IT project power boundaries were crossed and hence, develop perceptions of power misuse, or as termed in the literature, perceptions of illegitimate power. Building on existing work in the area of organisational power and resistance, we examine the extent to which four factors (IT project complexity, IT project benefit creation ability, top management commitment, and formal project management) influence an IT manager’s perceptions of illegitimate power in IT projects. Our empirical analysis confirmed that three of four factors affect perceptions of illegitimate power; only the hypothesis between formal project management and perceived illegitimate power was not significant. This paper contributes to IS research because it is an initial attempt to capture factors that trigger perceived illegitimate power. The research has practical implications because it demonstrates how illegitimate power perceptions emerge
Quantum conditional mutual information of W state in non-inertial frames
Quantum conditional mutual information (QCMI) is a versatile information
theoretic measure. It is used to find the amount of correlations between two
qubits from the perspective of a third qubit. In this work we characterise the
QCMI of tripartite W-states when some of the qubits are under accelerated
motion. Here for our investigations we consider a massless fermionic field in
the single mode approximation. We consider all possible situations with respect
to acceleration of the qubits. From our results we observe that QCMI can either
increase or decrease depending on the role of the qubit being accelerated.
Finally we discuss the connection between QCMI and correlations by studying the
biseparable and separable states.Comment: 22 pages, 6 figure
Probabilistic state preparation of a single molecular ion by projection measurement
We show how to prepare a single molecular ion in a specific internal quantum
state in a situation where the molecule is trapped and sympathetically cooled
by an atomic ion and where its internal degrees of freedom are initially in
thermal equilibrium with the surroundings. The scheme is based on conditional
creation of correlation between the internal state of the molecule and the
translational state of the collective motion of the two ions, followed by a
projection measurement of this collective mode by atomic ion shelving
techniques. State preparation in a large number of internal states is possible.Comment: 4 pages, 2 figures, 2 table
Photostatistics Reconstruction via Loop Detector Signatures
Photon-number resolving detectors are a fundamental building-block of optical
quantum information processing protocols. A loop detector, combined with
appropriate statistical processing, can be used to convert a binary on/off
photon counter into a photon-number-resolving detector. Here we describe the
idea of a signature of photon-counts, which may be used to more robustly
reconstruct the photon number distribution of a quantum state. The methodology
is applied experimentally in a 9-port loop detector operating at a
telecommunications wavelength and compared directly to the approach whereby
only the number of photon-counts is used to reconstruct the input distribution.
The signature approach is shown to be more robust against calibration errors,
exhibit reduced statistical uncertainty, and reduced reliance on a-priori
assumptions about the input state.Comment: 13 pages, 12 figure
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