Romanian Academy

About: Romanian Academy is a archive organization based out in Bucharest, Romania. It is known for research contribution in the topics: Population & Nonlinear system. The organization has 3662 authors who have published 10491 publications receiving 146447 citations. The organization is also known as: Academia Română & Societatea Literară Română.

Characterization of LaCoO3 powders obtained by water-based sol–gel method with citric acid

Abstract: LaCoO3-based materials are studied because they exhibit interesting, electrical, magnetic and catalytic properties. In this contribution, LaCoO3 powders were synthesized by sol–gel method in aqueous medium starting from metal nitrates or acetates, and citric acid as the chelating agent at room temperature. The relation between the reactions in solution, crystallization pathway and morphology is discussed. The dried powders were amorphous. Their thermal decomposition occurs stepwise upon heating to 400 °C for nitrate or 500 °C for acetate-based precursors, respectively. Pure perovskite LaCoO3 phase is formed after heating at 600 °C in the case of nitrates while in the case of acetates separation of phases occurs when 2 mol of citric acid are used. The choice of the precursor influences the morphology of the powders heated at 600 °C. The nitrate-based powders are composed of agglomerates of fine particles while the acetate-based powders mainly consist of gel fragments. Some preliminary electrical and catalytic properties are also presented.

Membrane Computing with External Output

Abstract: A membrane computing system (also called P system) consists of computing cells which are organized hierarchically by the inclusion relation: cells may include cells, which again may include cells, etc Each cell is enclosed by its membrane Each cell is an independent computing agent with its own computing program, which produces objects The interaction between cells consists of the exchange of objects through membranes The output of a computation is a partially ordered set of objects which leave the system through its external membrane The fundamental properties of computations in such P systems with external output are investigated These include the computing power, normal forms, and basic decision problems

Behaviour of cold-formed steel perforated sections in compression. Part 1—Experimental investigations

Abstract: This paper is the first part of a study devoted to interactive buckling of steel pallet racks compression members, carried out at the CEMSIG Research Centre 〈 http://cemsig.ct.upt.ro 〉 from “Politehnica” University of Timisoara; this part summarizes the experimental program [1] , [2] . Upright members of two different cross-sections, with and without perforations, were tested according to the guidelines of European design code for pallet rack systems EN15512 [3] , in order to determine the ultimate strength for specimens of length corresponding to local buckling, i.e. stub columns, and of length equal to the distance between two subsequent nodes of an upright frame, i.e. upright members. The last set of tests was devoted, mainly, to the observation of distortional buckling of upright members. However, depending on the cross-section dimensions, the length between two subsequent nodes can be often larger than distortional critical length. In such cases the test results correspond rather to the distortional–global interaction, than to pure distortion. Consequently, additional specimens having the length calibrated to correspond to distortional buckling and to interactive distortional-overall buckling range, respectively, were tested. Material tests and imperfection measurements were also performed.