Once triggered by the application of electric field and furnace heating, a polycrystal can be held in a constant state of flash with the furnace switched off. The specimen temperature can now be controlled by the curr...
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We report in-situ measurements of impedance spectroscopy during flash experiments with single crystals of cubic-yttria stabilized zirconia, conducted in ambient air at 300 °C to 700 °C under a direct current...
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In this work, we show that non-superabsorbent, thermo-responsive poly(N-isopropyl acrylamide) (PNIPAM) hydrogel particles (< 250 μm) can reduce autogenous shrinkage in cement paste and improve early-age stiff...
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In this work, we show that non-superabsorbent, thermo-responsive poly(N-isopropyl acrylamide) (PNIPAM) hydrogel particles (< 250 μm) can reduce autogenous shrinkage in cement paste and improve early-age stiffening that can be caused by traditional superabsorbent polymers (SAPs). Swelling measurements in DI water and cement filtrate solution suggest that SAP-induced early-age stiffening is caused by its super-absorbency in low-ionic solutions – a behavior not exhibited by non-superabsorbent PNIPAM. Addition of PNIPAM resulted in a 29% and 60% reduction in autogenous shrinkage strain at 14 days when used alone (0.3 wt% PNIPAM) and in combination with SAP (0.15% PNIPAM, 0.15% SAP), respectively, compared to a Control with no polymer addition. Furthermore, an addition of 0.3 wt.% PNIPAM exhibited a ∼29% and ∼37% decrease in static yield stress compared to a Control and 0.3 wt% SAP-modified cement pastes, respectively. Taken together, the results provide initial evidence to suggest that the use of hydrogels as internal curing agents may not necessarily require super-absorbency to reduce autogenous shrinkage. Non-superabsorbent hydrogels, like PNIPAM, may help reduce autogenous shrinkage while alleviating the effects of SAP-induced early-age stiffening.
A law previously found for shear moduli of crystalline materials is developed and extended to all elastic moduli in solids and structures. Shear moduli were previously shown to depend only on specific volume. The bulk...
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Ghost imaging (GI) enables reconstruction of the image of an object by measuring the intensity correlation of two beams, neither of which independently carries the spatial characteristics of the object. By exploiting ...
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Ghost imaging (GI) enables reconstruction of the image of an object by measuring the intensity correlation of two beams, neither of which independently carries the spatial characteristics of the object. By exploiting the space-time duality, GI has been extended from the spatial domain to the time domain, and has been successfully demonstrated in the optical regime. This article reports on the experimental demonstration of acoustic GI in the time domain. Using ultrasound instead of photons, we created high-quality ghost images of a temporal object, even in the presence of strong ambient noise. Our work offers a fresh approach for imaging disturbance-sensitive acoustic signals, and could open the gateway to identifying new approaches in acoustic sensing, dynamic imaging, and communications.
In order for fish scales to provide protection from predators without significantly compromising mobility, they have to be lightweight, flexible and tough. The Arapaima fish scale is a superb example of these properti...
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