Advanced Materials Research Vols. 311-313

Abstract: The influence of different curing conditions on hydration properties of fluorgypsum products formed by semi-dry pressing was studied. Laboratory experiments were conducted to investigate the compressive strength development, content of crystal water, and microcosmic crystal structure when four curing methods (nature curing, curing in standard curing chamber, soaked in water 3 min every other day or every day) and five curing temperatures (-20 °C, 0 °C, 10 °C, 20 °C, 35 °C) were used. The results indicated that the hydration properties of fluorgypsum products could be improved under proper curing methods and lower curing temperature.

Abstract: In this paper, desulfurized ash was focused on modifying the properties of fluorgypsum and quicklime was as a reference. According to the results of water-soluble fluoride and pH value of fluorgypsum with modifiers, the optimal fluoride retention and deacidification effect was obtained by adding 1.5 % of quicklime, 5 % of desulfurized ash from power station (DA-PS) or 2 % of desulfurized ash from sintered flue gas (DA-SFG), respectively. The continuous hydration process of the cementitious pastes of fluorgypsum was investigated by scanning electron microscopy (SEM). The morphology of the gypsum crystals was of irregular particle shapes dispersing inside. In the later hydrating age, the distribution of pores became uniform, and the connection between the crystals overlapped more compact. Considered the modification effects on cementitious pastes, DA-PS could take place of quicklime to achieve the fluoride retention and deacidification of fluorgypsum.

Abstract: Lignin was extracted from Acanthopanax senticosus remainders after pharmaceutical production process, with acetic acid-water as extracting reagent. Four factors effects, namely reaction temperature from 160°C to 220°C, reaction time from 40 min to 100 min, acetic acid concentration from 50% to 80% and solid-liquid ratio from 1:40 to 1:5, were studied and optimized by a four-level orthogonal array design (OAD) on lignin antioxidant capacity. The results indicated the reaction temperature and reaction time were significant factors among these factors. At the same lignin solution concentration, the acetic acid lignin antioxidant capacity was better than that of Kraft lignin, but much lower than that of butylated hydroxyanisole (BHA).

Abstract: A novel class of environmentally friendly protein-based bioplastics—cottonseed protein plastic sheets (CP-sheets)—were prepared by compression molding in the presence of cottonseed flour as main raw material, aldehydes as crosslink agent and glycerol as plasticizer. FTIR, TGA, tensile tests and water uptake measurements were applied to characterize the structure, thermal stability, mechanical properties and water absorption of the CP-sheets. It was found that the crosslinked CP-sheets (CP-FA, CP-GX and CP-GA) showed higher thermal stability and tensile properties, less water uptake than the CP-sheet withou crosslinking treatment (CP-0CL). The CP-sheets with good thermal, mechanical and hydrophobic properties are emerging and promising bioplastics for potential applications in food packaging as well as flower planting.

Abstract: In order to remove formaldehyde efficiently, the activated carbon was oxidized by nitric acid and then modified by etilenodiamina. The carbon treated with nitric acid and etilenodiamina showed the significant differences in IR spectrum compare with original activated carbon. The adsorption capacity for the formaldehyde of prepared carbon and original carbon were 2.4 mg/g and 1.0 mg/g, respectively. Results demonstrate that the amino group on carbon might improve the adsorption performance of carbon for formaldehyde.

Abstract: Cemented filling body exposed to acid mine water or high salinity mine water will be subjected to various kinds of physical and chemical attack. In this paper, the burning process of a modified special cement clinker used for corrosion-resisting cementitious material in fill mining is studied by means of TG-DTA, XRD, and chemical method. The main minerals of this kind of clinker are C₃S, C₂S, C₄A₃ , and C₄AF. The optimal firing temperature range of the clinker is from 1300°C to 1380°C, and a suitable amount of F- and SO3 in raw meals is helpful to the coexistence of C₃S and C₄A₃ in the clinker.

Abstract: The adsorption of naphthol green by peanut shell, which was chemically-modified by cross-linking with epichlorohydrin was studied with variation in the parameters of contact time and temperature. They were used for equilibrium adsorption uptake studies with naphthol green. The results revealed that adsorption equilibriums were rapidly established in about 3h. Three different kinetic models (i.e.,intraparticular diffusion model, Lagergren-first-order and second-order equations) were used to describe the adsorption kinetic mechanisms. The adsorption of naphthol green on epichlorohydrin modified peanut shell(EMPS) was not controlled by intraparticular diffusion. The kinetic adsorption data can be well simulated by the second-order equation and the adsorption might be rate-limiting controlled. The suitability of the adsorbent was evaluated by fitting the equilibrium data with Langmuir and Freundlich isotherms, which gave good fits with both isotherms.

Abstract: Novel bio-based composites were developed from maleate castor oil (MACO) and lignin through free radical initiated copolymerization between MACO and diluent monomer styrene(St). The morphology and structure of the composites were characterized by Fourier transform infrared spectroscope (FTIR) and scanning electron microscope (SEM). The mechanical and thermal behaviors of the composites were investigated, which showed the incorporation of a little of lignin in the castor oil based polymer can enhance the tensile properties of the matrix polymer greatly. This work provides a facile route to prepare bio-based composite materials from castor oil and lignin and can be extended to prepare other bio-based materials from reproducible resources.

Abstract: In this paper, a novel solution combing heuristic constraints with physical-based method for virtual interaction is proposed. With which, a grasping simulation is divided into three stages including pregrasping, preliminary grasping and stable grasping and the two techniques have been used in different phases. A dexterous virtual hand, consisting of geometric model, kinematics model, collision model and contact force model, is also constructed to be used in this solution. By analyzing the physical structures and perceptual characteristics of human finger, a haptic rendering algorithm is presented to obtain natural and stable virtual interaction.

Abstract: The mechanical characteristics and extremely hard working conditions of large die hydraulic press are considered. The limitations of traditional condition monitoring method are analyzed. A new condition monitoring system which consists of a digital and non-contact method for measuring column stress and a digital method for measuring moving beam’s spatial altitude based on machine vision is proposed. The basic principle and composition of the system are introduced in detail. The system is applied in 300MN large forging hydraulic press, and large amounts of monitoring data are collected. Data analysis is carried out. The laws of column stress distribution in different working conditions are found out. At last, some recommendations are proposed which is helpful for the safety operation and maintenance of large hydraulic press.