statement of problem: accumulation of plaque and staining due to a rough surface,  and  penetration  of  colourant  agents  from  food  and  beverages  in to the resin composite results in an incomplete polymerization. there is a little information on the effect of finishing and polishing techniques on the discoloration of nanohybrid and microhybrid composites when exposed to staining solutions...

In this paper electrical conductivity measurements and optical investigations takes place in AOT/ heptane/ (water or aqueous) systems. The water in oil system prepared with adding water in 50% by weight of AOT/ heptane solution.  In other systems instead of water, aqueous solutions of 1) zinc acetate and water 2) Potassium Hydroxide and water were used. In each phase, the trend of the electrica...

In this paper electrical conductivity measurements and optical investigations takes place in AOT/ heptane/ (water or aqueous) systems. The water in oil system prepared with adding water in 50% by weight of AOT/ heptane solution.  In other systems instead of water, aqueous solutions of 1) zinc acetate and water 2) Potassium Hydroxide and water were used. In each phase, the trend of the electrica...

The recognition of the limits of resources is almost as old as the realization that our planet is a sphere leading to concerns about sustainable resources management. Water resources in particular receive growing attention given its uneven distribution in many parts of the world. Engineering solutions to address water management challenges played significant roles in the past in areas such as a...

The manufacture of ethanol-free propolis solutions offers a broader application. A few trials with Lithuanian propolis have been conducted. The aims of the study are to manufacture propolis water and water-free solutions and evaluate the quality and antimicrobial activity of these solutions. The studied solutions containing 2.5%, 5%, and 10% propolis are prepared. As solvents, purified water, 7...

Freshwaters are recognized as dynamic systems that may be far-removed from equilibrium. A kinetic approach using the competing ligand exchange method with Chelex 100 as the competing ligand and inductively coupled plasmamass spectrometry to measure the dissociation kinetics was used to investigate the chemical speciation of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Pb(II) in model sol...

The year 2005 marks the beginning of the "International Decade for Action: Water for Life" and renewed effort to achieve the Millennium Development Goals (MDGS) to reduce by half the proportion of the world's population without sustainable access to safe drinking water and sanitation by 2015. Currently, UNICEF and WHO estimate that 1.1 billion people lack access to improved water supplies and 2...