the adsorption of lead (11) and copper (11) in a fixed bed column using activated carbonprepared from nipa palm nut was investigated. thomas model and yoon and nelson kinetic models were used to analyze the column performance. the rate constant for thomas model increased with increase in flow rate and initial ion concentration but remained constant at varying bed height. adsorption capacity for...

let $r$ be a commutative ring with zero-divisor set $z(r)$. the total graph of $r$, denoted by$t(gamma(r))$, is the simple (undirected) graph with vertex set  $r$ where two distinct vertices areadjacent if their sum lies in $z(r)$.this work considers minimum zero-sum $k$-flows for $t(gamma(r))$.both for $vert rvert$ even and the case when $vert rvert$ is odd and $z(g)$ is an ideal of $r$it is s...

the consolidation test method proposed by terzaghi and used in most soil mechanic laboratories has limitations and weaknesses. to get correct results, improvement and modification of the test method is essential. several experimental methods, such as constant loading rate, gradient and constant rate of strain (crs) have been used over the past 40 years. of these methods, crs is more advantageou...

State estimation and power flow analysis are important tools for analysis, operation and planning of a power system. In this paper, a new state estimation method based on the extended weighted least squares (WLS) method for considering both measurement errors and model inaccuracy is presented. Two bus, three bus, and IEEE 14 bus test cases are employed to evaluate the accuracy of the method. Th...

in the maximum flow network interdiction problem, an attacker attempts to minimize the maximum flow by interdicting flow on the arcs of network. in this paper, our focus is on the nodal interdiction for network instead of the arc interdiction. two path inequalities for the node-only interdiction problem are represented. it has been proved that the integrality gap of relaxation of the maximum fl...