焦炭显微结构及矿物质存在下反应性变化规律探讨

分析了焦炭显微结构及其对焦炭反应性的基本影响,探讨了矿物质的存在对焦炭显微结构的影响机理及催化作胛特征。焦炭光学显微结构对焦炭反应性影响顺序为各向同性、类丝炭和破片〉细粒镶嵌〉粗粒镶嵌〉流动型片状结构。当有矿物质存在时,其顺序恰好相反。     

攀枝花矿产资源特征及循环经济发展策略探讨

文章着重描述了攀枝花矿产资源特征、资源矿物流向和资源产品定位,分析了资源矿物使用行业的不同特点,明确了针对攀枝花矿产资源利用的循环经济目标,根据资源循环利用技术水平和资源循环开发现状,提出了攀枝花矿的循环经济发展策略.     

青海省能源矿产需求预测研究

建立灰色系统模型和回归模型,预测了青海省第一产业、第二产业、第三产业、城乡居民生活对能源矿产的需求强度,预测了青海省人口发展变化情况和产业结构变化情况。在此基础上,采用部门分析法预测了青海省2005年、2010年、2015年和2020年对煤炭、石油、天然气矿产的需求量,同时根据预测结果提出了能源结构调整的建议。     

Calcium phosphate crystallization on polyglycine, polytyrosine and polymethionine

The kinetics of hydroxyapatite (HAP) crystallization on the polyaminoacids polyglycine, polytyrosine, polymethionine, was investigated by the constant composition technique. The apparent order for the crystallization process was found to be 2, indicative of a surface diffusion control mechanism. There are three possible mechanisms for critical nucleus formation with size n* = 3 ± 1 as defined by computational chemistry calculations at 310 K. The calculated surface energy from kinetic data for the growing HAP phase was 109 ± 15 mJ m^− 2.     

Elastic tensor of the forsterite (Mg2SiO4) under pressure

A complete elastic tensor of the low-pressure structure of the magnesium orthosilicate (Mg₂SiO₄, forsterite) is determined by an ab initio technique for the pressure range P=0–240 kB. The geologically important quantities: density, sound velocity, Young's modulus, Poisson's ratio, crystal anisotropy, are derived from the calculated data. A systematic increase of crystal's anisotropy with pressure has been noticed. The results agree well with the available experimental data.     

Effect of quartzite and granite in wear surfaces on dry sliding

Abstract

The wear surfaces abraded with quartzite and granite were subjected to scratch tests. Sharp and blunt indenters were used with various constant loads to produce controlled abrasive wear tracks. The characteristics of deformation mechanisms and material removal were further studied using a scanning electron microscope to determine the differences in the tribological behaviour between the quartzite and granite wear surfaces.

The results indicate that quartzite residues are more uniformly distributed as individual particles on the wear surfaces and therefore provide more stable frictional forces. In the case of granite the abrasive residues are rather non-uniformly collected into piles of abrasives.     

Digital image-based numerical modeling method for prediction of inhomogeneous rock failure

This paper presents a two-dimensional digital image-based numerical modeling method for prediction of inhomogeneous rock failure behavior under loadings. Actual inhomogeneities of granitic rocks are extracted from color images of the granite cross-sections. They are represented as the internal spatial distribution of three main granite minerals (quartz, feldspar and biotite). The actual mineral spatial distribution on granite cross-section is then incorporated into conventional numerical software packages to examine the rock failures under loading. Some digital image processing algorithms are presented to isolate and identify the main internal minerals and their distribution from color digital images. A simple method is proposed to transform the actual image data into vector data for generation of finite meshes or grids. The vector data are used directly as uniform square element meshes or grids that can be inputted into the existing software packages. The finite difference software package FLAC is used as an example for the present investigation. The conventional Mohr–Coulomb and tensile stress failure criteria are used to examine the failure behavior of a circular granite cross-section under the conventional Brazilian indirect tensile test loading conditions. The numerical results indicate that the vertical tensile crack initiates in a biotite located near the geometrical center of the granite cross-section and the actual spatial distribution of the three minerals plays an important role in modifying the propagation pattern of the tensile crack from its theoretical position at the central vertical diameter of a homogeneous circular cross-section. The numerically predicted failure load and tensile strength values for inhomogeneous granite are much lower than the expected values.     

Exergoecology: A thermodynamic approach for accounting the Earth's mineral capital. The case of bauxite–aluminium and limestone–lime chains

As man extracts minerals, the natural deposits become depleted in quantity and concentration, and hence the mineral wealth of the Earth decreases. This paper explains the exergoecological method used for calculating the mineral exergy bonus that Nature gives us for free for providing minerals concentrated in mines and not dispersed in the Earth's crust. The method is based on two concepts: Exergy and the Exergy cost. Exergy measures the minimum (reversible) work required to extract and concentrate the materials from a Reference Environment (RE) to the conditions found in Nature. This RE can be approximated to a completely degraded crepuscular planet with the absence of fossil fuels and mineral deposits. And the exergy cost accounts for the actual exergy required for accomplishing the same process with available technologies. These costs are complementary to the conventional extraction, land-recovering, processing and refining costs. The case studies of two industrial chains: bauxite–alumina–aluminium, and limestone–calcite–lime are presented and discussed. As the method provides values in energy units, the annual exergy decrease in the mineral endowment of the planet due to the extraction of minerals can now take into account the fossil fuel's exergy as well as the non-fuel mineral exergy costs.     

Mineral Dissolution and the Evolution of k0

Adequate knowledge of the in situ state of stress can be essential to the analysis of geotechnical systems. However, the measurement and prediction of k0 remain difficult. In particular, limited attention has been given to the evolution of k0 during the formation history of the soil and diagenetic processes such as mineral dissolution. Experimental and numerical results show that grain mass loss due to mineral dissolution produces a pronounced horizontal stress drop under zero lateral strain conditions; the state of stress may reach the active shear failure ka condition and internal shear planes may develop. While horizontal stress recovery often follows upon further dissolution, marked differences in fabric are observed between the pre and postdissolution soil structures.     

Nutritional and anti-nutritional components in Pachyrhizus erosus L. tuber

Tuber of Pachyrhizus erosus L., an underutilized crop, was analyzed to determine its proximate chemical composition, vitamin, mineral, and amino acid contents, and enzymatic activity. The anti-nutritional factors were also determined. The tuber had a high level of moisture, appreciable amounts of carbohydrate, crude fibre and protein and negligibly low amount of lipid. The total caloric value corresponded to 39 kcal/100 g. The amino acid profile was deficient compared to the [FAO/WHO (1973). Energy and Protein Requirements. Technical Report Series (Vol. 52, pp. 1–118). Switzerland, Geneva: WHO.] recommended pattern. The micro- and macro-nutrient analysis revealed the tuber to be potential source of potassium, sodium, phosphorus, calcium and magnesium. The tuber contained a significant amount of ascorbic acid. Thiamine, riboflavin, pyridoxine, niacin and folic acid were also detected. Very negligible contents of anti-nutrient components were observed. Comparison of these data to those of several other commonly consumed local tubers revealed that P. erosus tuber could be included in dietary formulae for man or monogastric animals, especially in those areas where carbohydrate is in short supply.