Several a posteriori error estimators for mortar mixed finite element discretizations of elliptic equations are derived. A residual-based estimator provides optimal upper and lower bounds for the pressure error. An efficient and reliable estimator for the velocity and mortar pressure error is also derived, which is based on solving local (element) problems in a higher-order space. The interface...

ABSTRACT: Many traditional brick-and-mortar businesses supplement their physical outlets with e-commerce capabilities on the Web, but there has been lit tle empirical research on the underlying dynamics of the “click-and-mortar” business approach. This paper develops a conceptual framework that highlights the four types of synergies obtained by integrating e-commerce with physical infrastructur...

The design of repair mortars started from the characterization of the original mortar samples preserved in small areas in the floors of the Dungeon Tower, Bač Fortress. Two materials (waste brick and clay material) were investigated in order to select the pozzolanic material which later was a component of the repair mortar. Based on the compatibility test of the examined old mortars and of the ...

Mortars containing carbon, polyethylene, and stainless steel fibers at the same volume fraction and with similar fiber diameters were compared in terms of tensile, compressive, and flexural properties. Carbon fibers, though having the lowest tensile modulus, stren[?th, and elongation at break among the fiber types, [?ave mortar of the highest tensile strenf?th and lowest cost; polyethylene fibe...

Cellulose ethers are polymers frequently introduced into mortar formulations in order to improve water retention capacity and workability of the freshly mixed materials. Cellulose derivatives can induce excellent water retention thanks to the possible superposition of two phenomena. Mortar rheology can impact water retention, increasing media viscosity. Other specific effects provided by cellul...

a new model is proposed for two-dimensional simulation of the concrete fracture in compression. the model generated by using the voronoi diagram method and with considering random shape and distribution of full graded aggregates at the mesoscopic level. the aggregates modeled by combining irregular polygons, which then is placed into the concrete with no intersection between them. by this new m...

The mechanical and durability properties of recycled aggregate concrete (RAC) are generally inferior to conventional due the old mortar attached surface original aggregate, which induces more complicated interfacial transition zones (ITZs) in RAC. microbial induced carbonate precipitation (MICP) modification is a novel environmentally-friendly method improve ITZs In this study, physical coarse ...

Sulfur cathode materials in lithium–sulfur chemistry suffer from poor electronic conductivity and shuttle of lithium polysulfides during charging discharging. Serious effects the sluggish redox reaction kinetics severely limit development batteries with high sulfur loading, impeding practical process batteries. Herein, a honeycomb73x02010;structured CoF2@C is introduced as functional layer adhe...

Silicas chemically modified with a number of sulfur-containing groups (mercaptopropyl, mercaptophenyl, dipropyl disulfide, thiadiazole thiol, dithiocarbamate and thiourea derivatives) were proposed for the separation preconcentration precious metals. These adsorbents quantitatively extracted metals from 0.5 to 4 M solutions hydrochloric acid. It allowed their high concentrations non-ferrous, al...