Synthesis and characterization of ZnO nanopowder by non-basic

Nanocrystalline ZnO particles were prepared from methanolic solutions of zinc acetate dihydrate without using base such as NaOH or LiOH through a colloid process carried out at a low temperature of 60 o C. The precipitate obtained after 12-72h contained ZnO, covered with polymeric species of zinc hydroxo acetate. The reaction course was studied by mass spectrometry means. To complete the hydrolysis process, up to pure ZnO, it was necessarily to reflux the white precipitate separate from methanolic solution, in water at 80 o C. We found that reaction time in the presence of methanol primarily influenced the size of the particles, while the reaction time in the presence of water mainly influenced the ZnO purity

STATE OF THE ART REGARDING CONSERVATIVE TILLAGE TECHNOLOGIES

Following the expansion of soil degradation processes due to conventional agriculture and technological mistakes, over the years, the so-called conservative agricultural technologies have been studied and implemented in practice. These technologies have contributed substantially to the improvement of soil fertility and productivity and, thus, of other environmental resources. The most important component of conservation technological systems, as in the case of conventional ones, is soil tillage – loosening and processing – and the introduction of seed into the soil. Switching from conventional tillage systems to the conservative ones was not easy and generated a lot of questions that needed relevant answers, scientifically based, some of them being obtained through fundamental and applied research carried out under local specific conditions. Conservative systems are based on the less intense loosening of soil, made by different methods, without furrow return and only while maintaining a given amount of crop residues on soil surface, is being considered for this reason as environmental protection strategies. In this paper is presented an analysis of the state of research on the implementation in agriculture of conservative tillage technologies and the technical-economic and environmental impacts of applying these conservative technologies. Also, there are presented the most advanced research on optimal construction of equipment for soil processing in conservation system

Sequential Valuation Networks: A New Graphical Technique for Asymmetric Decision Problems

This paper is a short (14-pp) version of a longer working paper titled "Sequential Valuation Networks for Asymmetric Decision Problems," University of Kansas School of Business Working Paper No. 286, January 2001, Revised June 2004, available from KU Scholarworks.This paper deals with representation and solution of asymmetric decision problems. We describe a new graphical representation called sequential valuation networks, which is a hybrid of Covaliu and Oliver’s sequential decision diagrams and Shenoy’s asymmetric valuation networks. Sequential valuation networks inherit many of the strengths of sequential decision diagrams and asymmetric valuation networks while overcoming many of their shortcomings. We illustrate our technique by representing and solving a modified version of Covaliu and Oliver’s Reactor problem

Sequential Valuation Networks: A New Graphical Technique for Asymmetric Decision Problems

Abstract. This paper deals with representation and solution of asymmetric decision problems. We describe a new graphical representation called sequential valuation networks, which is a hybrid of Covaliu and Oliver’s sequential decision diagrams and Shenoy’s asymmetric valuation networks. Sequential valuation networks inherit many of the strengths of sequential decision diagrams and asymmetric valuation networks while overcoming many of their shortcomings. We illustrate our technique by representing and solving a modified version of Covaliu and Oliver’s Reactor problem.