Abstract: In this paper, kinetics of reductive leaching of manganese dioxide ore by ferrous ion in sulfuric acid media has been examined. Experimental results show that increasing temperature from 20 to 60 °C and decreasing ore particle size from −16+20 to −60+100 mesh considerably enhance both the dissolution rate and efficiency. Molar ratios of Fe2+/MnO2 and H2SO4/MnO2 in excess to the st...

Barite is an important additive material to increase the weight of excavation mud. It has been used extensively in the excavation mud industry. The barite particle sizes used in excavation mud is very important. There is a direct relationship between the amount on the sift of 200 and 325 mesh. By reducing particle sizes of the 200 and 325 mesh, the specific gravity of the barite power increased...

Actualistic comparison of death assemblages with local living communities is a standard approach to estimating the quality of paleoecological data, but wide variation in methods of data collection and analysis undermines attempts to draw general conclusions. Here, I apply both standard and meta-analytic statistics to a stringently constructed database of 19 molluscan live–dead studies in order ...

A size-governed quadtree mesh generation method is presented in this paper to deal with planar domains of arbitrary shape. The tree decomposition provides a convenient control space, which can be used to determine the element sizes, as well as a neighboring space, which allows for the quick searching of mesh items. The sizes of the tree cells are adjusted to match the size speciications (deened...

BACKGROUND AND OBJECTIVES We aimed to evaluate the first human use of magnetic resonance-visible implants for intraperitoneal onlay repair of incisional hernias regarding magnetic resonance presentability. METHODS Ten patients were surgically treated with intraperitoneally positioned superparamagnetic flat meshes. A magnetic resonance investigation with a qualified protocol was performed on p...

The finite element (FE) mesh sizing has great influence on computational time, memory usage, and accuracy of FE analysis. Based on a systematic in-depth study of the geometric complexity of a set of connected surfaces, a computational procedure for the generation of FE mesh sizing function is proposed. The computational procedure has three main steps: (1) Generation of source points that determ...

This paper gives a procedure to control the size variation in a mesh adaption scheme where the size speci cation (the so-called control space) is used to govern the mesh generation stage. The method consists in replacing the initial control space by a reduced one by means of size or metric. It allows to improve, a priori, the quality of the adapted mesh and to speed up the adaption procedure. S...