2,391 research outputs found
Internally supported flexible duct joint
An internally supported, flexible duct joint for use in conducting fluids under relatively high pressures in systems where relatively large deflection angles must be accommodated is presented. The joint includes a flexible tubular bellows and an elongated base disposed within the bellows. The base is connected through radiating struts to the bellows near mid-portion and to each of the opposite end portions of the bellows through a pivotal connecting body. A motion-controlling linkage is provided for linking the connecting bodies, whereby angular displacement of the joint is controlled and uniformity in the instantaneous bend radius of the duct is achieved as deflection is imposed
Universal bellows joint restraint permits angular and offset movement
Universal joint-type restraint that employs ball joints permits maximum angular and lateral offset movement in a bellows joint without danger of rupture or pressure drop in the line. It is used in high pressure and high temperature applications in refineries, steam plants, or stationary power plants
Mindful Administration of IS Security Policies
Managers of information systems have ethical, moral and legal obligations to protect their organization’s intellectual property. They often look to frameworks such as the Control Objectives for Information and related Technology (CobIT) to guide them to what data needs to be secured or standards such as the ISO/IEC 27000 series to provide best practices regarding their policies on how to safeguard this information. However, these policies are either vague in the details or not fluid and flexible enough to account for the unexpected security events that may render them obsolete. For example, Google recently released an online suite of applications that would allow an organization’s employees to collaborate on items of intellectual capital stored on Google’s servers outside the control of the organization’s information technology (IT) department. Additionally, new techniques have been discovered to break the encryption of data that was previously thought to be lost when the device containing it was powered off. While these events certainly have utility to practitioners, they also pose new threats to the security of intellectual capital created and stored on IT artifacts. This paper advocates mindfulness (Weick and Sutcliffe, 2001) as a necessary component of choosing and adapting security policies to better predict the unexpected security threats that may come as a result of technological change, environmental forces, or organizational use of IT
Churchman\u27s Inquiring Systems: Kernel Theories for Knowledge Management
Churchman [1971] defines inquiry as an activity that produces knowledge. He examines the epistemologies of five schools of philosophy from the perspective of general systems theory, asking the question as to whether each is suitable as the basis for the design of computer-based inquiring systems. He considers systems design and design theory in some detail. We believe that Churchman\u27s inquiring systems can form the basis for the design of knowledge management systems and that the IS research community has hardly tapped the potential of inquiring systems in that regard. Mason and Mitroff [1973] brought inquiring systems into the IS literature early on, essentially making the work endogenous to the field. We argue that building on inquiring systems can contribute to developing IS as a discipline by maintaining continuity in research and developing a theory that IS can call its own. We believe that the lack of use of Churchman\u27s work may be due to its lack of visibility in recent years and attempt to remedy that by summarizing the basics of the inquirers in some detail, trying not to interpret, but to remain faithful to the original. The paper encourages readers to study the original and develop their own notion of how the inquirers might be used in knowledgemanagement work. There are probably as many different perspectives on how inquiring systems could support KMS as there are IS researchers willing to study them. We would like to encourage a proliferation of such perspectives
Reversibility in Chemical Reactions
open access bookIn this chapter we give an overview of techniques for the
modelling and reasoning about reversibility of systems, including outof-
causal-order reversibility, as it appears in chemical reactions. We consider
the autoprotolysis of water reaction, and model it with the Calculus
of Covalent Bonding, the Bonding Calculus, and Reversing Petri Nets.
This exercise demonstrates that the formalisms, developed for expressing
advanced forms of reversibility, are able to model autoprotolysis of
water very accurately. Characteristics and expressiveness of the three
formalisms are discussed and illustrated
A robust, scanning quantum system for nanoscale sensing and imaging
Controllable atomic-scale quantum systems hold great potential as sensitive
tools for nanoscale imaging and metrology. Possible applications range from
nanoscale electric and magnetic field sensing to single photon microscopy,
quantum information processing, and bioimaging. At the heart of such schemes is
the ability to scan and accurately position a robust sensor within a few
nanometers of a sample of interest, while preserving the sensor's quantum
coherence and readout fidelity. These combined requirements remain a challenge
for all existing approaches that rely on direct grafting of individual solid
state quantum systems or single molecules onto scanning-probe tips. Here, we
demonstrate the fabrication and room temperature operation of a robust and
isolated atomic-scale quantum sensor for scanning probe microscopy.
Specifically, we employ a high-purity, single-crystalline diamond nanopillar
probe containing a single Nitrogen-Vacancy (NV) color center. We illustrate the
versatility and performance of our scanning NV sensor by conducting
quantitative nanoscale magnetic field imaging and near-field single-photon
fluorescence quenching microscopy. In both cases, we obtain imaging resolution
in the range of 20 nm and sensitivity unprecedented in scanning quantum probe
microscopy
Actin: disposition, quantities, and estimated effects on lung recoil and compliance
. ␣-Actin: disposition, quantities, and estimated effects on lung recoil and compliance. J Appl Physiol 91: [459][460][461][462][463][464][465][466][467][468][469][470][471][472][473] 2001.-We have investigated the basis and implications of pneumoconstriction by measuring disposition and quantities of ␣-smooth muscle actin in rat and guinea pig lungs and modeling its effects on lung recoil and compliance. A robust marker of contractility, ␣-smooth muscle actin appears in smooth muscle or myofibroblast-like cells in pleura, airways, blood vessels, and alveolar ductal tissues. In each site, we measured its transected area by immunofluorescent staining and frequency-modulated scanning confocal microscopy. We incorporated these data in a model of the parenchyma consisting of an extensive elastic network with embedded contractile structures. We conclude that contraction at any one of these sites alone can decrease parenchymal compliance by 20-30% during tidal breathing. This is due mostly to the stiffness of activated contractile elements undergoing passive cycling; constant muscle tension would have little effect. The magnitude of the effect corresponds with known responses of the lung to hypocapnia, consistent with a homeostatic function in which gas exchange is defended by redistributing ventilation away from overventilated units. alveolar duct; intensity-modulated multiple-wavelength scanning confocal microscopy; lung compliance; ventilationperfusion ratio; hypocapni
Evaluation of Methods for De Novo Genome Assembly from High-Throughput Sequencing Reads Reveals Dependencies That Affect the Quality of the Results
Recent developments in high-throughput sequencing technology have made low-cost sequencing an attractive approach for many genome analysis tasks. Increasing read lengths, improving quality and the production of increasingly larger numbers of usable sequences per instrument-run continue to make whole-genome assembly an appealing target application. In this paper we evaluate the feasibility of de novo genome assembly from short reads (≤100 nucleotides) through a detailed study involving genomic sequences of various lengths and origin, in conjunction with several of the currently popular assembly programs. Our extensive analysis demonstrates that, in addition to sequencing coverage, attributes such as the architecture of the target genome, the identity of the used assembly program, the average read length and the observed sequencing error rates are powerful variables that affect the best achievable assembly of the target sequence in terms of size and correctness
KELT-20b: A Giant Planet With A Period Of P ~ 3.5 Days Transiting The V ~ 7.6 Early A Star HD 185603
We report the discovery of KELT-20b, a hot Jupiter transiting a early A star, HD 185603, with an orbital period of days. Archival and follow-up photometry, Gaia parallax, radial velocities, Doppler tomography, and AO imaging were used to confirm the planetary nature of KELT-20b and characterize the system. From global modeling we infer that KELT-20 is a rapidly rotating ( ) A2V star with an effective temperature of K, mass of , radius of , surface gravity of , and age of . The planetary companion has a radius of , a semimajor axis of au, and a linear ephemeris of . We place a upper limit of on the mass of the planet. Doppler tomographic measurements indicate that the planetary orbit normal is well aligned with the projected spin axis of the star ( ). The inclination of the star is constrained to , implying a three-dimensional spin–orbit alignment of . KELT-20b receives an insolation flux of , implying an equilibrium temperature of of ∼2250 K, assuming zero albedo and complete heat redistribution. Due to the high stellar , KELT-20b also receives an ultraviolet (wavelength nm) insolation flux of , possibly indicating significant atmospheric ablation. Together with WASP-33, Kepler-13 A, HAT-P-57, KELT-17, and KELT-9, KELT-20 is the sixth A star host of a transiting giant planet, and the third-brightest host (in V ) of a transiting planet
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