1,721,115 research outputs found
An overview of carbonation curing of Portland cement-metakaolin-limestone ternary binders
No full textReviews on autogenous shrinkage and hydration of CSA cement upon different curing temperatures
No full textEffects of pre-reset conditions on reset discharge from ramp reset waveforms in AC plasma display panel
No full textThe basic characteristics of reset discharges related to a wall voltage and a priming effect were investigated under a conventional ramp driving scheme. The reset discharges could be minimized by controlling the wall voltage which is determined by pre-reset conditions. Accordingly, the current study presents a simple pre-reset condition for minimizing the reset discharge. Essentially, it is not only to reduce the duration of reset discharges but also to reduce the intensity of light emissions when the wall voltage polarity is opposite to the external voltage polarity.This work
was supported by the Research Program of the Korea Science and Engineering
Foundation under Grant R08-2003-000-10376
Evolution of the binder gel in carbonation-cured Portland cement in an acidic medium
No full textThe present study investigated the evolution of a binder gel in carbonation-cured Portland cement in an acidic medium. Three types of Portland cement with varying chemical compositions were carbonation-cured and exposed to H2SO4 or HCl. An acid attack induced significant changes in the local environment of Al in normally cured cement showing the formation of ettringite and Friedel's salt, while the local environment of Al in carbonation-cured cement mainly consisted of a tetrahedral aluminate structure and showed much less structural alteration. A thermal analysis showed that the carbonation products of belite were more stable than those of alite, with less gypsum formation under H2SO4 in the cement with relatively more belite. Depolymerization of the carbonation product, Ca-modified silicate gel, was observed in the samples immersed in acid.
Recent studies on mechanical and thermal properties of calcium aluminate cement blends upon exposure to high temperature
No full textFabrication of a disposable biochip for measuring percent hemoglobin Alc (%HbAlc)
No full textA disposable biochip for measuring percent hemoglobin A1c, a glycosylated hemoglobin (HbA1c), in blood is presented, in which a air of p interdigitated array electrodes, a micropump, and a microchannel were on-chip integrated by bonding a glass wafer and a polydimethylsiloxane (PDMS) layer. The ratio of HbA1c to hemoglobin, %HbA1c, represents the average glucose level during the life span of red blood cells, and thus, it can be a more reliable and accurate index of diabetes. For %HbA1c measurement, the blood sample was split into two streams, one with HbA1c and the other without HbA1c by binding of HbA1c with in-amino-phenylboronic acid agarose beads. Each stream passed by the interdigitated electrodes resulting in an electric signal via an electrochemical reaction. The %HbA1c was calculated with both signals. A first device of 40 mm x 20 mm x 3 mm was fabricated by bonding two glass wafers and two PDMS layers with a vertical sample reservoir. A second device of 75 mm x 25 turn x 1.5 mm was produced by bonding one glass wafer and one PDMS layer yielding a simplified configuration compared to the first device. For verifying the devices, blood suspensions were transported and cell lysis was tested. A 50-mu L blood suspension extracted from a mouse was mixed with ethylenediaminetetraacetic acid, diluted with phosphate buffered saline to lower its viscosity, and the suspension was then transported at approximately 30 mu m/s in the microchannel by the micropump, which produced oxygen gas. The condition for blood lysis was determined empirically with 2% Triton X-100, a neutral detergent. (c) 2006 Elsevier B.V. All fights reserved
An overview on the effect of temperature and salinity on microbial induced calcium carbonate precipitation of Sporosarsina pasteurii
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