455 research outputs found

    Influence of Warping on Stress for Restrained Concrete Slabs: For Application to CRCP

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    Continuously-reinforced concrete pavement (CRCP) is widely used in transportation system because of its low maintenance requirement. However, the need for large volumes of steel creates a high cost for new construction. The Illinois Tollway is preparing to substantially renovate highways in and around Chicago and this work seeks to understand how concretes of varying mixture designs can be made thinner by reducing the amount of built-in stress. The experiment examines warping in beams subjected to various degrees of restraint, in an effort to assess effectiveness at reducing warping in continuously reinforced concrete pavements. Value added methodologies such as internal curing with fine lightweight aggregate and topically-applied shrinkage-reducing admixture (SRA) were applied to a controlled concrete mixture design. The experimental program examines the warping of a composite concrete-steel beam with differing degrees of restraint, accomplished through using a 1/4 and ½” steel plate with a 2.5 concrete section . Each beam undergoes seven days of uni-axial warping, subjected to a controlled temperature and humidity environment (23+/-2C and 50 +/- 2 % RH), with a linear variable differential transformer to monitor endpoint deflection. Results indicate that as degree of restraint increases, the associated, or built-in , stress increases too; however, the deflection decreases by as much as a factor of two between unrestrained and 1/2 restraint. These findings potentially serve as a solution for effectively reducing the amount of concrete necessary for sustained loading associated with CRCP while mitigating warping and stresses associated

    Easily Accessible Experiments Demonstrating Interference

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    A brief but detailed description of simple experiments to be used in Physics classrooms

    Efficient Palladium-Triggered Release of Vorinostat from a Bioorthogonal Precursor

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    Bioorthogonal uncaging strategies have recently emerged as an experimental therapeutic approach to control drug release. Herein we report a novel masking strategy that enables to modulate the metal chelating properties of hydroxamic acid groups by bioorthogonal chemistry using Pd-functionalized resins. This novel approach allowed to devise an inactive precursor of the histone deacetylase inhibitor vorinostat that was efficiently uncaged by heterogeneous Pd catalysis in cell culture models of glioma and lung cancer

    Short Term High-Repetition Back Squat Protocol Does Not Improve 5-km Run Performance

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    International Journal of Exercise Science 13(7): 1770-1782, 2020. The purpose of this study was to evaluate the hypothesis that a novel high-repetition, low-resistance back squat training protocol, designed to stimulate high-intensity interval training, improves 5-km run performance. Fifteen runners [4 male, 11 female; 150 + minutes of endurance exercise/week; age = 22.7 ± 2.0 y; 21.5 ± 2.2 kg/m2 BMI] in this single-group test-retest design completed two weeks of back squats consisting of three sets of 15-24 repetitions at 60% of estimated one-repetition max (1RM), three times per week (1-2 days of rest between sessions). Outcome tests included a 5-km outdoor timed run, laboratory indirect calorimetry to quantify substrate oxidation rates during steady-state submaximal exercise (60% and 70% heart rate max (HRmax)), and estimated 1RM for back squats. Back squat estimated 1RM increased by 20% (58.3 ± 18.5 to 70.2 ± 16.7 kg, P \u3c 0.001). However, 5-km run times due to the back squat protocol did not significantly change (Pre-Squats: 23.9 ± 5.0 vs. Post-Squats: 23.7 ± 4.3 minutes, P = 0.71). Likewise, the squat training program did not significantly alter carbohydrate or lipid oxidation rates during steady-state submaximal exercise at 60% or 70% of HRmax (P values ranged from 0.36 - 0.99). Short term high-repetition back squat training does not appear to impact 5-km run performance or substrate utilization during submaximal exercise

    The California-Kepler Survey. VI: Kepler Multis and Singles Have Similar Planet and Stellar Properties Indicating a Common Origin

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    The California-Kepler Survey (CKS) catalog contains precise stellar and planetary properties for the \Kepler\ planet candidates, including systems with multiple detected transiting planets ("multis") and systems with just one detected transiting planet ("singles," although additional planets could exist). We compared the stellar and planetary properties of the multis and singles in a homogenous subset of the full CKS-Gaia catalog. We found that sub-Neptune sized singles and multis do not differ in their stellar properties or planet radii. In particular: (1.) The distributions of stellar properties MM_\star, [Fe/H], and vsiniv\mathrm{sin}i for the Kepler sub Neptune-sized singles and multis are statistically indistinguishable. (2.) The radius distributions of the sub-Neptune sized singles and multis with P>3P > 3 days are indistinguishable, and both have a valley at 1.8 R\sim1.8~R_\oplus. However, there are significantly more detected short-period (P<3P < 3 days), sub-Neptune sized singles than multis. The similarity of the host star properties, planet radii, and radius valley for singles and multis suggests a common origin. The similar radius valley, which is likely sculpted by photo-evaporation from the host star within the first 100 Myr, suggests that planets in both singles and multis spend much of the first 100 Myr near their present, close-in locations. One explanation that is consistent with the similar fundamental properties of singles and multis is that many of the singles are members of multi-planet systems that underwent planet-planet scattering.Comment: Accepted for publication in the Astronomical Journal. 23 pages, 9 figure

    Revised Masses and Densities of the Planets around Kepler-10

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    Determining which small exoplanets have stony-iron compositions is necessary for quantifying the occurrence of such planets and for understanding the physics of planet formation. Kepler-10 hosts the stony-iron world Kepler-10b, and also contains what has been reported to be the largest solid silicate-ice planet, Kepler-10c. Using 220 radial velocities (RVs), including 72 precise RVs from Keck-HIRES of which 20 are new from 2014 to 2015, and 17 quarters of Kepler photometry, we obtain the most complete picture of the Kepler-10 system to date. We find that Kepler-10b (R_p = 1.47 R_⊕) has mass 3.72 ± 0.42 M_⊕ and density 6.46 ± 0.73 g cm^(-3). Modeling the interior of Kepler-10b as an iron core overlaid with a silicate mantle, we find that the iron core constitutes 0.17 ± 0.11 of the planet mass. For Kepler-10c (R_p = 2.35 R_⊕) we measure mass 13.98 ± 1.79 M_⊕ and density 5.94 ± 0.76 g cm^(-3), significantly lower than the mass computed in Dumusque et al. (17.2 ± 1.9 M_⊕). Our mass measurement of Kepler-10c rules out a pure stony-iron composition. Internal compositional modeling reveals that at least 10% of the radius of Kepler-10c is a volatile envelope composed of hydrogen–helium (0.2% of the mass, 16% of the radius) or super-ionic water (28% of the mass, 29% of the radius). However, we note that analysis of only HIRES data yields a higher mass for planet b and a lower mass for planet c than does analysis of the HARPS-N data alone, with the mass estimates for Kepler-10 c being formally inconsistent at the 3σ level. Moreover, dividing the data for each instrument into two parts also leads to somewhat inconsistent measurements for the mass of planet c derived from each observatory. Together, this suggests that time-correlated noise is present and that the uncertainties in the masses of the planets (especially planet c) likely exceed our formal estimates. Transit timing variations (TTVs) of Kepler-10c indicate the likely presence of a third planet in the system, KOI-72.X. The TTVs and RVs are consistent with KOI-72.X having an orbital period of 24, 71, or 101 days, and a mass from 1 to 7 M_⊕

    Atomic layer deposition of PbCl2, PbBr2 and mixed lead halide (Cl, Br, I) PbXnY2-n thin films

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    Atomic layer deposition offers outstanding film uniformity and conformality on substrates with high aspect ratio features. These qualities are essential for mixed-halide perovskite films applied in tandem solar cells, transistors and light-emitting diodes. The optical and electronic properties of mixed-halide perovskites can be adjusted by adjusting the ratios of different halides. So far ALD is only capable of depositing iodine-based halide perovskites whereas other halide processes are lacking. We describe six new low temperature (Peer reviewe

    AR2, a novel automatic muscle artifact reduction software method for ictal EEG interpretation: Validation and comparison of performance with commercially available software.

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    Objective: To develop a novel software method (AR2) for reducing muscle contamination of ictal scalp electroencephalogram (EEG), and validate this method on the basis of its performance in comparison to a commercially available software method (AR1) to accurately depict seizure-onset location. Methods: A blinded investigation used 23 EEG recordings of seizures from 8 patients. Each recording was uninterpretable with digital filtering because of muscle artifact and processed using AR1 and AR2 and reviewed by 26 EEG specialists. EEG readers assessed seizure-onset time, lateralization, and region, and specified confidence for each determination. The two methods were validated on the basis of the number of readers able to render assignments, confidence, the intra-class correlation (ICC), and agreement with other clinical findings. Results: Among the 23 seizures, two-thirds of the readers were able to delineate seizure-onset time in 10 of 23 using AR1, and 15 of 23 using AR2 (
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