Exclusion and inflammation in the clinic are observed for various reasons including material chemical composition, physical properties as well as macro- and micro-structure of the implants, surface condition of the implants, and also patient dependent factors. Cytotoxicity expression of cells is a central issue in current biocompatibility to screen the potential implant materials and drugs. This study was aimed at investigation reaction between the potential implant materials and surround tissue. Cytotoxicity of human and rat osteoblast in the material extracts was determinated by testing standards such as GHS assay, MTT assay, alkaline phosphatase activity assay, LDH assay, and Lowry assay. Research results demonstrated that compared with the control condition polystyrene culture plate both human and rat osteoblast cells have normal phenotypic expression in hydroxyapatite extract, and this expression was statistically restricted in hydroxyapatite-spinel extract. However, this restrict, e.g. cytotoxicity could be partially eliminated by immersion treatment of the materials in culture medium.
Based upon the thermodynamic analysis of the nucleation of diamond crystal, the effects of synthesis temperature and pressure on the nucleation of diamond crystal, diamond growth and output of diamond crystal, particle size and strength were discussed. The results show that the excess pressure has an important effect on the critical radius of nucleation and thermodynamic barrier in the formation of a critical nucleus. Considering the excess pressure, the expression of diamond nucleation rate was obtained.
A novel type of thermal stabilizer—lanthanum tris (mono-i-octyl phthalate) (LTMP) was synthesized by double-decomposition reaction of sodium mono-i-octyl phthalate with lanthanum chloride at 60 °C. Sodium mono-i-octyl phthalate was prepared by sodium hydrate and mono-i-octyl phthalate prepared by reaction of isooctyl alcohol and phthalic anhydride in the presence of sulfuric acid catalyst at 110 °C. The yield of lanthanum tris (mono-i-octyl phthalate) is about 84.5%. Its thermal stabilities were measured by heat-ageing oven test when incorporated into PVC. The experimental results show that the heat stability time is about 40min at 190 °C when adding 3phr (per hundred resin) to PVC. The thermal stability of this product is better than that of Ca-Zn complex and basic lead salt stabilizers, and equal to that of dibutyltin diaurate.
The electrode process of pyrite in diethyldithiocarbamate (DDTC) solution pH 11.4 was investigated by using cyclic voltammetry, potentiostatic and chronopotentiometry. Tetraethylthioram disulphide (TETD) was electrodeposited on pyrite electrode surface as the electrode potential is higher than 0.2 V. The relationship of the current density caused by diffusion and reaction time can be ascertained as i=1/(9.08×10−5+4.77×10−3t0.5), and the diffusion coefficient of DDTC on pyrite surface is about 3.72×10−6 cm2/s. At pH 11.4, the thickness of TETD adsorbed on pyrite surface is about 1.63 molecule layer. The electrochemical dynamics equation of the reduction of TETD on pyrite surface is given as η=0.116−0.064log[1−(t/τ)0.5]. The kinetic parameters were determined as follows: the exchange current density (i0) is 3.08 µA/cm2; the transmission coefficient(α) is 0.462.
The paper analyzed the groups naked and the transformed of fibrous brucite, wollastonite, chrysotile asbestos, sepiolite, palygorskite, clinoptilolite, crocidolite and diatomaceous earth mineral dusts by using IR under acid and alkali etched, strong mechanical and polarized molecular interaction. The results show that the active site focuses on ends in stick dusts and on defects or hole edges in pipe dusts. The inside active sites of dusts play the main role in small molecular substance. The shape of dusts affects their distributions and densities of active sites. The strong mechanical and weak chemical force make the active site feature of minerals change, the powder process brings about more naked surface groups and more combined types. The dust activity relates to the type, contribution, and naked level of surface groups. The studied dust surface groups are mainly as follows: OH−, Mg(OH)−, Si-O-Si, Ca-O-Si, -Mg-OH2,-Al(Si)-OH, -Mg(Ca)-OH2, Ca-O,-Si···OH, Mg(Fe)-OH. Due to the difference of surface composition and structure, the minerals have a large disparity on activity and character of surface groups. The one side surface group of chrysotile layer is the same as fibrous brucite and stripped layer with more naked group. The fibrous sepiolite and palygorskite surface OH− similar to crocidolite is naked with their surface structural defects and cleavage. The more development of mineral defects, the higher of OH− (H2O+) content, the main H2O+ of clinoptilolite is partly transformed into H+, NH4+ or OH−. The acid etched process may change OH− concentration, distribution and increase the defects and porosity of mineral fiber surface. The alkali etched has no effect on Si-O, Si-OH etc. and destroyed Al-O, Al-OH− acid site of sepiolite, palygorskite and clinoptilolite. Some surface groups of remnant differ from original dusts. The surface process of small polarized molecular or middle moleular’s branch may produce ionation and new coordinate bond, and change the active properties and level of original dusts, such as the porous minerals producing acid site may act as some assistance catalysis in biochemistry process.
Three types of rock specimens, three-point bending specimen, anti-symmetric four-point bending specimen and direct shearing specimen, were used to achieve Mode I, Mode II and mixed mode I–II fracture, respectively. Microscopic characteristics of the three fracture modes of brittle rock were studied by SEM technique in order to analyze fracture behaviors and better understand fracture mechanisms of different fracture modes of brittle rock. Test results show that the microscopic characteristics of different fracture modes correspond to different fracture mechanisms. The surface of Mode I fracture has a great number of sparse and steep slip-steps with few tearing ridges and shows strong brittleness. In the surface of Mode II fracture there exist many tearing ridges and densely distributed parallel slip-steps and it is attributed to the action of shear stress. The co-action of tensile and shear stresses results in brittle cleavage planes mixed with streamline patterns and tearing ridges in the surface of mixed mode I–II fracture. The measured Mode II fracture toughness KII C and mixed mode I–II fracture toughness KmC are larger than Mode I fracture toughness KI C · KII C is about 3.5 times KI C, and KmC is about 1.2 times KI C.
In order to investigate the effective control method of spontaneous combustion in the mining of sulfide ore deposits. This paper presents the testing results of several selected chemicals (water glass, calcium chloride, calcium oxide, magnesium oxide and their composites) as oxidation suppressants for sulfide ores. A weight increment scaling method was used to measure suppressant performance, and this method proved to be accurate, simple and convenient. Based on a large number of expeiments, the test results show that four types of chemical mixtures demonstrate a good performance in reducing the oxidation rate of seven active sulfide ore samples by up to 27% to 100% during an initial 76 d period. The mixtures of water glass mixed with calcium chloride and magnesium oxide mixed with calcium chloride can also act as fire suppressants when used with fire sprinkling systems.
In terms of viscoelasticity, the relevant theory of wave in granular media is analyzed in this paper. Under the conditions of slight deformation of granules, wave equation, complex number expressions of propagation vector and attenuation vector, attenuation coefficient expressions of longitudinal wave and transverse wave, etc, are analyzed and deduced. The expressions of attenuation coefficients of viscoelastic longitudinal wave and transverse wave show that the attenuation of wave is related to frequency. The higher the frequency is, the more the attenuation is, which is tested by the laboratory experiment. In addition, the energy dissipation is related to the higher frequency wave that is absorbed by granular media. The friction amongst granular media also increase the energy dissipation. During the flowing situation the expression of transmission factor of energy shows that the granular density difference is the key factor which leads to the attenuation of vibrating energy. This has been proved by the experiment results.
Traditional stabilization of backfilling material is done by using Portland cement. However, the high price of cement forced mining engineers to seek cheaper binding materials. Fly ash, which is the industrial waste from thermal power plant, possess the potential activity of jellification, and can be used in cemented fill as a partial substitute for cement to reduce the fill cost. Tests were done during the past few years in Xinqiao Pyrite Mine and Phoenix Copper Mine to determine the technology parameters and the suitable content of fly ash. Specimens with different cement/fly/ash tailings (sands) ratios were tested to obtain the strength values of the fill mass based on the analyses of both the chemical composition and physical and mechanical properties of fly ash. The compressive strength of specimens with a ratio of 1:2:8 (cement to fly ash to tailings) can reach 2 MPa after 90 d curing, totally meeting the requirement of artificial pillar and reducing the fill cost by 20%–30%.
Graphite is naturally floatable due to its hydrophobic property and also soft and smears on other gangue particles, rendering the gangue more or less floatable too. Due to this reason it is important to concentrate on areas such as suitable flotation reagents, depression agents, pH modifiers, and particle size to be fed during the process. The paper surveys and analyses the suitable particle size to be fed to achieve high-grade concentrate. According to the work carried out the author suggested the ideal cost effective flotation flow sheet for improved results at Bogala Mines in Sri Lanka.
Wulong gold deposit hosted in granite and fine-grained diorite dikes, is a typical gold deposit of quartz vein type. Granite and fine-grained diorite dikes in the ore deposit were altered by metallogenic fluid. Based on the altered zoning, the samples of petrochemistry were collected and major and trace elements were analyzed systematically. Calculation of rock mass balance shows that the major elements (SiO2, K2O, P2O5, Fe2O3) in the two typical altered rocks are clearly added into the altered system, and that trace elements (V, Y, Zr, Ni, Co, Sr) assume an increasing and decreasing tendencies in the altered granite and altered diorite dike, respectively. The fluid/rock ratios are 30.17–181.00 and 115.44–692.67 respectively for altered granite and altered diorite dike, they have profoundly effects on metallogenesis.
The paper discussed the limitation of ‘Dominant wavelength theory’. The theoretical model and nonhomogeneous differential equation of fold and deformation of a monolayer sandwiched-in limited and different thickness terranes are proposed by using mechanics of elasticity. In addition, the “Dominant wavelength theory’ is proved by the experimental folding in elastic materials. The folds of a monolayer sandwiched-in limited and different thickness terranes are studied inside and are explored in the field.
Active set method and gradient projection method are currently the main approaches for linearly constrained convex programming. Interior-point method is one of the most effective choices for linear programming. In the paper a predictor-corrector interior-point algorithm for linearly constrained convex programming under the predictor-corrector motivation was proposed. In each iteration, the algorithm first performs a predictor-step to reduce the duality gap and then a corrector-step to keep the points close to the central trajectory. Computations in the algorithm only require that the initial iterate be nonnegative while feasibility or strict feasibility is not required. It is proved that the algorithm is equivalent to a level-1 perturbed composite Newton method. Numerical experiments on twenty-six standard test problems are made. The results show that the proposed algorithm is stable and robust.
As to solve the online monitoring of the inner temperature and freezing profile of the reaction shaft of flash smelting furnace, simulation of the wall in the reaction shaft in a flash smelting furnace was made through numerical computation. The computational results are very near the data got in site. The error of the moving boundary is approximately 3%, and that of the temperature is less than 5%. It is proved that the simulation software is applicable for practice to monitor the temperature and moving boundary inside the hearth online. Based on a large number of the data computed, the relation between the change of the moving boundary and inner temperature is summarized, and the great influence of the cooling system on the forming and stability of the moving boundary inside the hearth is emphasized, which provide the theoretical bases for optimizing the flash smelting operation.