258 research outputs found

    Additive Manufacturing, Modeling and Performance Evaluation of 3D Printed Fins for Surfboards

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    We demonstrate that Additive Manufacturing (3D printing) is a viable approach to rapidly prototype personalised fins for surfboards. Surfing is an iconic sport that is extremely popular in coastal regions around the world. We use computer aided design and 3D printing of a wide range of composite materials to print fins for surfboards, e.g. ABS, carbon fibre, fibre glass and amorphous thermoplastic poly(etherimide) resins. The mechanical characteristics of our 3D printed fins were found to be comparable to commercial fins. Computational fluid dynamics was employed to calculate longitudinal (drag) and tangential (turning) forces, which are important for surfboard maneuverability, stability and speed. A commercial tracking system was used to evaluate the performance of 3D printed fins under real-world conditions (i.e. surfing waves). These data showed that the surfing performance of surfboards with 3D printed fins is similar to that of surfboards with commercial fins

    A key role for peroxynitrite-mediated inhibition of cardiac ERG (Kv11.1) K+ channels in carbon monoxide–induced proarrhythmic early afterdepolarizations

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    Exposure to carbon monoxide (CO) causes early afterdepolarization arrhythmias. Previous studies in rats indicated arrhythmias arose due to augmentation of the late Na+ current. The purpose of the present study was to examine the basis of CO-induced arrhythmias in guinea pig myocytes in which action potentials more closely resemble those of human myocytes. Whole-cell current- and voltage-clamp recordings were made from isolated guinea pig myocytes and also from HEK293 cells expressing wild-type or a C723S mutant form of Kv11.1 (ERG). We also monitored formation of peroxynitrite (ONOO-) in HEK293 cells fluorimetrically. CO, applied as the CO releasing molecule, CORM-2, prolonged action potentials and induced early after-depolarizations (EADs) in guinea pig myocytes. In HEK293 cells CO inhibited wild-type but not C723S mutant Kv11.1 K+ currents. Inhibition was prevented by an antioxidant, mitochondrial inhibitors or inhibition of nitric oxide formation. CO also raised ONOO- levels, an effect reversed by the ONOO- scavenger, FeTPPS which also prevented CO inhibition of Kv11.1 currents, and abolished the effects of CO on Kv11.1 tail currents and action potentials in guinea pig myocytes. Our data suggest that CO induces arrhythmias in guinea pig cardiac myocytes via ONOO--mediated inhibition of Kv11.1 K+ channel

    Comment Re: Non-Compete Clause Rulemaking, Matter No. P201200

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    Within signed law professors and law students submitted this letter to the Federal Trade Commission, writing in their individual capacities, not as agents of their affiliated institutions, in support of the Federal Trade Commission’s proposed rule to ban most non-compete clauses (the “Proposal”) as an unfair method of competition. This letter offers comments in response to areas where the FTC has requested public comment. To make our views clear, this letter contains the following sections: I. Summary of the Proposal; II. The Commission Should Consider Expanding Its Definition of Non-Compete Clauses to Prevent Employers from Requiring Workers to Quit Before Seeking Alternative Employment; III. Non-Compete Clauses Are Unfair Methods of Competition; IV. Non-Compete Clauses Negatively Impact Workers and Their Families; V. The Proposed Rule Protects Small Businesses and Entrepreneurs; and VI. The Commission Should Consider a Factor Test for Its Unfairness Analysis for Senior Executive

    Berkeley Supernova Ia Program I: Observations, Data Reduction, and Spectroscopic Sample of 582 Low-Redshift Type Ia Supernovae

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    In this first paper in a series we present 1298 low-redshift (z\leq0.2) optical spectra of 582 Type Ia supernovae (SNe Ia) observed from 1989 through 2008 as part of the Berkeley SN Ia Program (BSNIP). 584 spectra of 199 SNe Ia have well-calibrated light curves with measured distance moduli, and many of the spectra have been corrected for host-galaxy contamination. Most of the data were obtained using the Kast double spectrograph mounted on the Shane 3 m telescope at Lick Observatory and have a typical wavelength range of 3300-10,400 Ang., roughly twice as wide as spectra from most previously published datasets. We present our observing and reduction procedures, and we describe the resulting SN Database (SNDB), which will be an online, public, searchable database containing all of our fully reduced spectra and companion photometry. In addition, we discuss our spectral classification scheme (using the SuperNova IDentification code, SNID; Blondin & Tonry 2007), utilising our newly constructed set of SNID spectral templates. These templates allow us to accurately classify our entire dataset, and by doing so we are able to reclassify a handful of objects as bona fide SNe Ia and a few other objects as members of some of the peculiar SN Ia subtypes. In fact, our dataset includes spectra of nearly 90 spectroscopically peculiar SNe Ia. We also present spectroscopic host-galaxy redshifts of some SNe Ia where these values were previously unknown. [Abridged]Comment: 34 pages, 11 figures, 11 tables, revised version, re-submitted to MNRAS. Spectra will be released in January 2013. The SN Database homepage (http://hercules.berkeley.edu/database/index_public.html) contains the full tables, plots of all spectra, and our new SNID template

    A molten salt test loop for component and instrumentation testing

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    Molten salt is an effective coolant for a wide range of applications, including nuclear reactors, concentrated solar power, and other high temperature industrial heat transfer processes. The technical readiness level of components and instrumentation for high-temperature molten salt applications needs improvement for molten salt to be more widely adopted. A molten salt test loop was designed, built, and commissioned as a test bed to address these issues. The molten salt test loop at Abilene Christian University was built out of 316 stainless steel with a forced flow centrifugal-type pump, and was instrumented for remote operation. A low-temperature molten nitrate salt was used in this system, which was designed to operate at temperatures up to 300 ◦C and flow rates up to 90 liters per minute. This paper describes the loop design, computational fluid dynamics modeling, construction, and commissioning details. An outline of the data acquisition and control systems is presented. Salt samples were taken before and after introduction into the loop, and melting points were measured both before and after salt circulation. Performance of the system is discussed as well as improvements required for higher temperature loops envisioned for the future

    Galaxy and mass assembly (GAMA): A deeper view of the mass, metallicity and SFR relationships

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    A full appreciation of the role played by gasmetallicity (Z), star formation rate (SFR) and stellar mass (M*) is fundamental to understanding how galaxies form and evolve. The connections between these three parameters at different redshifts significantl

    Food Anticipatory Activity Behavior of Mice across a Wide Range of Circadian and Non-Circadian Intervals

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    When rodents are fed in a limited amount during the daytime, they rapidly redistribute some of their nocturnal activity to the time preceding the delivery of food. In rats, anticipation of a daily meal has been interpreted as a circadian rhythm controlled by a food-entrained oscillator (FEO) with circadian limits to entrainment. Lesion experiments place this FEO outside of the light-entrainable circadian pacemaker in the suprachiasmatic nucleus. Mice also anticipate a fixed daily meal, but circadian limits to entrainment and anticipation of more than 2 daily meals, have not been assessed. We used a video-based behavior recognition system to quantify food anticipatory activity in mice receiving 2, 3, or 6 daily meals at intervals of 12, 8, or 4-hours (h). Individual mice were able to anticipate as many as 4 of 6 daily meals, and anticipation persisted during meal omission tests. On the 6 meal schedule, pre-prandial activity and body temperature were poorly correlated, suggesting independent regulation. Mice showed a limited ability to anticipate an 18 h feeding schedule. Finally, mice showed concurrent circadian and sub-hourly anticipation when provided with 6 small meals, at 30 minute intervals, at a fixed time of day. These results indicate that mice can anticipate feeding opportunities at a fixed time of day across a wide range of intervals not previously associated with anticipatory behavior in studies of rats. The methods described here can be exploited to determine the extent to which timing of different intervals in mice relies on common or distinct neural and molecular mechanisms
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