نتایج جستجو برای: alkali
تعداد نتایج: 16336 فیلتر نتایج به سال:
in this study, a temperature-dependent of the dispersion coefficients is calculated from equation state.the lennard-jones lj (12-6-3) effective pair potential function and simple thermodynamic argumentwith the input pvt data of liquid metals are used to calculate the dispersion coefficients. the dispersioncoefficients ( , , ) 3 6 12 c c c are found to be a linear function of 1/t1+α , where t is...
a simple, rapid and sensitive spectrophotometric method has been proposed for the determinationof vanadium (iv). the method is based on the catalytic effect of v (iv) on the oxidation of alkali blue bypotassium bromate at ph 4. the rate of decrease in the absorbance of alkali blue (at 572 nm) wasproportional to the concentration of v (iv) in the range of 100-6000 ng ml-1. the detection limit wa...
Three alkali swelling methods were used to treat two kinds of kraft pulp fibers. The morphological and chemical properties of the treated fibers were elucidated in terms of alkali concentration, with the aim of developing bulky paper and conserving wood resources. The effects of beating before and after alkali swelling were examined. The water retention value of fibers increased when higher con...
Aggregates containing certain constituents can react with alkali hydroxides in concrete. The reactivity is potentially harmful only when it produces significant expansion (Mather 1975). This alkali-aggregate reactivity (AAR) has two forms—alkali-silica reaction (ASR) and alkali-carbonate reaction (ACR, sometimes called alkali-carbonate rock reaction, or ACRR). ASR is more often a concern than A...
Aggregates containing certain constituents can react with alkali hydroxides in concrete. The reactivity is potentially harmful only when it produces significant expansion (Mather 1975). This alkali-aggregate reactivity (AAR) has two forms—alkali-silica reaction (ASR) and alkali-carbonate reaction (ACR, sometimes called alkali-carbonate rock reaction, or ACRR). ASR is more often a concern than A...
purpose : studies show that phenytoin is effective in improvement of different chronic ulcers such as venous stasis ulcers, and diabetic ulcers. the exact mechanism is yet not clear investigators thought that phenytoin might help to heal intractable corneal ulcers by reducing inflammation, differentiating limbal fibroblasts, and promoting the invasion of the cornea with new blood vessels as sho...
oxidative coupling of methane has been studied over (mn+a+w)/sio2 catalysts in a continuous–flow microreactor, where a represents an alkali ion of li, na, k or cs having different weight percents. the main aim of this study is to find the role of alkali ions in interaction between mn and w species with sio2 to make a proper structure for catalyzing oxidative coupling of methane (ocm) reaction. ...
The changes in cell surface properties associated with alkali stress can significantly disrupt cell metabolism and structures, preventing effective interactions between bacterial cells and their environment. Listeria monocytogenes is known to display an adaptive response to alkali stress that enhances its capacity to more effectively survive subsequent severe alkali challenge. In this study, we...
Ground granulated blast furnace slag (ggbs), can reduce the alkali load in concrete, despite its relatively high alkali content. Most research has been devoted to the efficacy of slag with an alkali content of less than 1.0% and this is reflected in guidance documents. A comparative assessment was made of the effect, if any, of the alkali level of ggbs on potential alkali-silica reactivity. Exp...
This work aims at providing a better understanding of the mechanical properties of the reaction rim in the alkali-silica reaction. The elastic modulus of the calcium alkali silicate constituting the reaction rim, which is formed at the interface between alkali silicate and Ca(OH)₂ in a chemically-idealized system of the alkali-silica reaction, was studied using nano-indentation. In addition, th...
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