Optimization of clay material mixture ratio and filling process in gypsum mine goaf

Because there is neither waste rock nor mill tailings in the gypsum mine, and the buildings on the goaf of gypsum mine are needed to be protected, the research proposed the scheme of the clay filling technology. Gypsum, cement, lime and water glass were used as adhesive, and the strength of different material ratios were investigated in this study. The influence factors of clay strength were obtained in the order of cement, gypsum, water glass and lime. The results show that the cement content is the determinant influence factor, and gypsum has positive effects, while the water glass can enhance both clay strength and the fluidity of the filing slurry. Furthermore, combining chaotic optimization method with neural network, the optimal ratio of composite cementing agent was obtained. The results show that the optimal ratio of water glass, cement, lime and clay (in quality) is 1.17:6.74:4.17:87.92 in the process of bottom self-flow filling, while the optimal ratio is 1.78:9.58:4.71:83.93 for roof-contacted filling. A novel filling process to fill in gypsum mine goaf with clay is established. The engineering practice shows that the filling cost is low, thus, notable economic benefit is achieved.

Low-Cost Preparation of Boron Nitride Ceramic Powders

The amorphous boron nitride ceramic powders were prepared at 750-950 ℃ by the low-cost urea route, and the effects of preparation temperatures, molar ratios of the raw materials and oxidation treatment on the composition, structure and surface morphology of the products were investigated through FT-IR, XRD and SEM. The results show that the products ceramize and crystallize gradually with the increase of the temperature. When the molar ratio and reaction temperature are 3：2 and 850 ℃, respectively, the products have high purity, compact structure and nice shape. The oxidation treatment at 450 ℃ will not impair the composition and structure of boron nitride but effectively remove the impurities.

Effects of Different Material Ratios on the Dissolution of Tongmai Pills

[Objectives]To study the effects of different material ratios on the dissolution of Tongmai pills.[Methods]Based on mixture uniform experiment design,the fiber,starch and grease-resin materials in Tongmai pills were proportioned.The contents of strychnine,brucine,paeoniflorin,calycosin,ferulic acid,hesperidin and salvianolic acid B in the solution were determined by HPLC,and the content of total flavonoids was determined by ultraviolet spectrophotometry.The weight coefficient of index components was determined by analytic hierarchy process,and the SAS software was used to optimize the dissolution model and calculate the dissolution parameter T40.MATLAB was used to establish a mathematical model and realize the data visualization between material ratio and dissolution parameter T40.[Results]The mathematical model between material ratio and dissolution parameter was T40=8.93-5.31X1-5.83X2+17.67X1X3(X1,X2,X3 are fiber,starch and grease-resin materials respectively,r2=0.9706,P=0.01,RMSE=0.5696).[Conclusions]Fiber can effectively promote the dissolution(P<0.05).Starch can promote the dissolution,but the effect is not obvious(P=0.05).The interaction between fiber and grease-resin can inhibit the dissolution,but was not significant(P=0.07).

Physical Properties of the Function and Number of Empirical Macrohardness of the Material: Universal Physical Unit of Measurement of Macro Hardness (Part 2)

Results of analytical studies of the physical properties of the function and number of empirical macrohardness based on the standard experimental force diagram of kinetic macroindentation by a sphere.An analytical comparison method and a criterion for the similarity of the physical and empirical macrohardness of a material are proposed.The physical properties of the hardness measurement process using the Calvert-Johnson method are shown.The physical reasons for the size effect when measuring macrohardness are considered.The universal physical unit and standard of macrohardness of kinetic macroindentation by a sphere is substantiated.

Electrochemical Performance of Nickel Hydroxide/Activated Carbon Supercapacitors Using a Modified Polyvinyl Alcohol Based Alkaline Polymer Electrolyte

Polyvinyl alcohol （PVA）-sodium polyacrylate （PAAS）-KOH-H2O alkaline polymer electrolyte film with high ionic conductivity was prepared by a solution-casting method. Polymer Ni（OH）2/activated carbon （AC） hybrid supercapacitors with different electrode active material mass ratios （positive to negative） were fabricated using this alkaline polymer electrolyte, nickel hydroxide positive electrodes, and AC negative electrodes. Galvanostatic charge/ discharge and electrochemical impedance spectroscopy （EIS） methods were used to study the electrochemical performance of the capacitors, such as charge/discharge specific capacitance, rate charge/discharge ability, and charge/discharge cyclic stability. Experimental results showed that with the decreasing of active material mass ratio m（Ni（OH）2）/m（AC）, the charge/discharge specific capacitance increases, but the rate charge/discharge ability and the charge/discharge cyclic stability decrease.

Selective ensemble modeling based on nonlinear frequency spectral feature extraction for predicting load parameter in ball mills

Strong mechanical vibration and acoustical signals of grinding process contain useful information related to load parameters in ball mills. It is a challenge to extract latent features and construct soft sensor model with high dimensional frequency spectra of these signals. This paper aims to develop a selective ensemble modeling approach based on nonlinear latent frequency spectral feature extraction for accurate measurement of material to ball volume ratio. Latent features are first extracted from different vibrations and acoustic spectral segments by kernel partial least squares. Algorithms of bootstrap and least squares support vector machines are employed to produce candidate sub-models using these latent features as inputs. Ensemble sub-models are selected based on genetic algorithm optimization toolbox. Partial least squares regression is used to combine these sub-models to eliminate collinearity among their prediction outputs. Results indicate that the proposed modeling approach has better prediction performance than previous ones.

Study on Compost Utilization of Horticultural Waste

This study aimed to explore the optimal material ratio for composting of horticultural waste,which was expected to improve the utilization rate of this waste.To be specific,horticultural waste and edible fungus residue were mixed with pig manure,rapeseed cake,or compound fertilizer and the carbon-nitrogen ratio of the pile was adjusted to 30∶1 for composting.The raw materials at different ratios were prepared to determine the temperature variation,maturity,germination index,and total contents of nitrogen,phosphorus,and potassium of the compost.The results showed that the high-temperature period,germination index,and total nutrient content of the compost in the three treatments all met standard of organic fertilizer.T1 presented the longest high-temperature period and highest germination index and contents of nitrogen,phosphorus,and potassium after 42 d of composting.To sum up,the three treatments all yielded composts with no toxin and standard maturity and nutrients as commercial organic fertilizer,particularly T1.In areas short of livestock manure,the rapeseed cake or compound fertilizer can also be used as a nitrogen source for the composting of horticultural waste.

A research of material input and environmental impact for Chinese economy:1990-2005

The process of economic activities is on the basis of tremendous material inputs.China has been discharging an enormous amount of waste,giving rise to a wide range of environmental impacts.The method of economy-wide material flow analysis(EW-MFA)is one of the effective tools to examine the flow of materials entering physical economies,and recognize early environmental problems.Relevant researches are still at the early stage in China and most focus on material throughput but are rarely concerned about the utilization of recycling resource and environmental impact.Based on more than 3,000 items of data related,materials entering Chinese economy are classified into three types,and then the characteristics of material input and environmental impact are presented for the years 1990-2005 by using the indicators derived from EW-MFA.The Ratio of Recycled Material(RRM) is added as the new indicator in order to be in accordance with the need of circular economy being promoted in China.Results show that the great changes in the structure of material input cause the continuous increase of industrial solid waste emissions and the bogging down of material productivity.The RRM reveals that the utilization of recycling resources remains at a fairly low level in China.Finally,some weakness of EW-MFA is discussed according to the calculated results.

Correlation between morphology parameters and skid resistance of asphalt pavement

Pavement skid resistance is critical for contributing to traffic safety.In this study,two pavement specimens were fabricated using different aggregate gradations and binder contents.Compaction efforts were made to ensure the same porosity of the two specimens.Some parameters related to the surface morphology were measured using the sand patching method and a 3D laser.The parameters include mean texture depth(MTD),interface roughness(R_(a)),skewness(R_(sk)),kurtosis(R_(ku)),fractal dimension(D)and parameters related to material ratio curve.Relationships between these parameters and skid resistance were quantitatively developed.Skid resistance increased along with the increase of MTD,R_(a) and D.From the surface A to surface B,MTD increased from 0.23 to 1.10 mm,R_(a) increased from 0.93 to 1.80 mm,D increased from 2.25 to 2.43 and the British Pendulum Number increased from 80 to 97 accordingly.The comprehensive analysis could assist scholars and practitioners to facilitate the understanding of tyre-pavement interaction and further assist pavement design.

Damping of Ni–Mn–Ga epoxy resin composites

By combining the advantages of effcient damping and high mechanical properties,Ni-Mn-Ga particle composites have a very good prospect for applications in damping structure design.In this paper,a ferromagnetic shape memory alloy Ni-Mn-Ga composite is prepared.Ni-Mn-Ga particle/bisphenol-A epoxy composite cantilever beam vibration tests under a magnetic feld and without the magnetic feld are conducted to analyze the structural damping ratios n.Meanwhile,the damping characteristics of the Ni-Mn-Ga composite are studied through the axial loading-unloading method and the acoustic emission signals method.The damping coeffcient of the composite for different Ni-Mn-Ga volume fractions is obtained.The interface properties of the composite are discussed by micro examination and axial loading.The relationships between the damping of the composite and that of the component materials are discussed.The specifc damping capacity（SDC）and acoustic emission counts diagram of different specimens with different Ni-Mn-Ga volume fractions are analyzed.