An acyclic k-coloring of a graph G is a proper vertex coloring of G, which uses at most k colors, such that the graph induced by the union of every two color classes is a forest. In this note, we prove that every graph with maximum degree six is acyclically 11-colorable, thus improving the main result of [12].

heat stress effects on physical and mental health of workers and decreases human function. asphalt workers are both exposed to the heat of their working process and to the sun heat. this study aimed at evaluating thermal stress and its following function fall and the effect of asphalt work on the degree of heat stress and asphalt workers’ physiological parameters. the present study was done at ...

Agriculture is a function of temperature and precipitation. Any change in these parameters, above below the threshold value, will affect photosynthesis transpiration crops, leading to an overall negative impact on agriculture, threatening global food security. Underdeveloped developing worlds are most likely be affected due this situation because more than 80% population area economically depen...

using environmental-friendly methods in order to remove or reduce oil pollutants and their derivations in the environment are developing. in this study, the biodegrading ability of bacillus subtilis .sp which has been separated from oil-polluted soil was examined. it was revealed that it can reduce surface tension of growth medium and produce bio-surfactant at 37 and 20 degrees centigrade. also...

effectiveness of furfural as an organic inhibitor in 5 percent hydrochloric acid which is used in acid pickling of steel was evaluated. lungmuir, frumkin and flory-huggins isotherms [1, 2] were used to determine the parameters of effective adsorption, free energy and entropy of adsorption. furfural indicated an inhibition less than 17 percent in concentrations of 0.001 mole per liter for a dura...

using environmental-friendly methods in order to remove or reduce oil pollutants and their derivations in the environment are developing. in this study, the biodegrading ability of bacillus subtilis .sp which has been separated from oil-polluted soil was examined. it was revealed that it can reduce surface tension of growth medium and produce bio-surfactant at 37 and 20 degrees centigrade. also...

Effectiveness of furfural as an organic inhibitor in 5 percent hydrochloric acid which is used in acid pickling of steel was evaluated. Lungmuir, Frumkin and Flory-Huggins isotherms [1, 2] were used to determine the parameters of effective adsorption, free energy and entropy of adsorption. Furfural indicated an inhibition less than 17 percent in concentrations of 0.001 mole per liter for a dura...

Effectiveness of furfural as an organic inhibitor in 5 percent hydrochloric acid which is used in acid pickling of steel was evaluated. Lungmuir, Frumkin and Flory-Huggins isotherms [1, 2] were used to determine the parameters of effective adsorption, free energy and entropy of adsorption. Furfural indicated an inhibition less than 17 percent in concentrations of 0.001 mole per liter for a dura...

Purpose: The aim of this study was to evaluate the effect of oral microorganism on surface topography of acrylic resin denture base material. Materials and methods: Fifty rectangular plates of dimensions 30mm x 20mm x 1 mm were fabricated with heat polymerizing acrylic resin denture base material. an area of 10mm x 10 mm in the center of each acrylic plate was marked for evaluation of surface t...

in this study, the ability of generalized additive model (gam) for mapping potential distribution of ferula ovina boiss, and the description of species response curves to environmental variables were examined in fereidonshar region with area of 1000 square kilometers located in west of isfahan province. the presence and absence data of the species were collected from 278 sites (including 138 pr...