Advanced Materials Research Vols. 183-185

Abstract: The paper research on the factors of the lactide polymerization, which primarily were ontology purity, dosage of initiator, polymerization temperature, time and vacuum degree, etc. According to the molecular weight measuring in different conditions of synthesis PDLLA, the results shows that, through the control of polymerization conditions higher molecular weight of PDLLA can obtain, main parameters as the quality ratio of initiator and monomers is about 0.03%, the polymerization temperature is 140°C, time duration is 48h and vacuum is 0.05 mmHg.

Abstract: Rice straw (Oryza sativa L.) pulp was treated by high intensity homogenizer to make fibril and fibril aggregates. The rice straw fibril and fibril aggregates (RSFs) material was used as reinforcement in a RSFs/ Poly (vinyl alcohol) (PVA) nanocomposite that prepared by film casting. The diameter distribution of RSFs was investigated by laser diameter instrument (LDI) and its crystallinity was evaluated by wide angle X-ray diffraction (WAXD). The morphological of RSFs was investigated by scanning electron microscopy (SEM). The mechanical properties were measured by tensile test and the dynamic mechanics analysis (DMA), thermal stability tests, i.e., differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) and the Fourier transform infrared spectroscopy (FTIR) test were also performed, respectively.

Abstract: Rosin is reputed as green petroleum because it is renewable, not expensive, and environmental friendly. China is rich in rosin resources. In this report, rosin was used as raw material to prepare rosinyl amine salt (RAS) surfactant. The optimal reaction conditions of RAS was modified rosin and dimethylamine mole ratio of 1:2, reaction temperature of 78 oC and reaction time of 2 h. The chemical structure of the product was identified by Fourier transform infrared spectroscopy (FTIR), electrospray ionization-mass spectrometry (ESI-MS) and 1H nuclear magnetic resonance (NMR) analysis. As a surfactant, it has a critical micellar concentration (CMC) of 7.07×10-5mol/L, a surface tension of 44.36 mN/m, an emulsification activity of 5min, a height of foam of 165 mm, and a foam stability of 143 mm.

Abstract: A Company of YunNan, located at the basin of the Jinsha river, is a plant producing beer. The amount of its wastewater comes up to 1000 m3/ d, and Parameters of the influent are CODcr=1850mg/L, BOD5=600mg/L, SS=700mg/ L. The quality of effluent has been up to the gradeⅠof the discharge standard of GB8978-1996 by applying the treatment technology of two phase-anaerobic-SBR process. This technology enjoys both low investment and low operation cost.The beer wastewater has characteristics of high organic matter content, well bio-chemical and asymmetry exhaust. We carry on the craft choices and designs by researching the current treatments of beer wastewater and combining the technique development of related realms of internal and external while considering the special of the company.

Abstract: In this paper, the zero-span tensile strengths of tracheids of Chinese fir and Masson pine were investigated, and the effect of the moisture on the tracheid strength was also discussed. Furthermore, the influence of thermal treatment on the zero-span tensile strengths of tracheids were analysed, and research of relationship of zero-span tensile strengths, chemical components and cellulose crystallinity were also conducted. This study tried to explore the inherent mechanism of heat treatment on the cell level.

Abstract: Due to influence of size effect, the force properties in nanoscale are greatly different from those in macroscale and the traditional models of operation are becoming difficult to meet the development of nanoscale manipulation. To provide guiding theory for practical nano-manipulation, the nanoscale forces of contact and non-contact operation of nanowires are analyzed for nano-manipulation in SEM. The Vander Waals models among the probe, nanowire and substrate are modeled according to the force properties in nanoscale, and then the simplified models are simulated with MATLAB. The influence degree of various factors and the relationship of them during the operation are obtained. At last, experimental system is established to verify the correctness of the proposed models.

Abstract: TiO2 has its advantages in terms of degeneration of wastewater. However, dispersing Nano-TiO2 in water will make it hard to recycle and produce a giant waste of raw material, which would affect its prospect as a practical application. The main problem in the practice of photocatalytic technology is to prepare stable and highly active Nano-TiO2. It is a good way to prepare supported TiO2 by absorbing the active component of TiO2 to the surface of activated carbon. In this paper, we use activated carbon as the carrier and prepare supported TiO2 catalysts by the hydrolysis of titanium sulfate precipitation method. Then, we use active red X-3B to simulate the wastewater to study catalyst preparation methods and the factors that affect the photocatalytic performance.

Abstract: In this paper, an experimental model was built in the nonlinear finite element software LS-DYNA. A metal tube wrapped fiberglass epoxy composite outside (called “composite tube” for short) was impacted in its axial direction in the simulation. The key problems about building the model were discussed later. Comparing the simulation and experiment results, we proved the validity of the model. Furthermore, we applied the material type of the composite tube to vehicle longeron, and carried on the simulation of automobile frontal collisions in LS-DYNA. The simulation results showed using the new type composite material could reduce the longeron weight to original 33.76% without lowering the safety.

Abstract: With the improvement of casting and material technology, cast steel is continuously used in practical engineering projects. Domestic and foreign scholars studied the performance of cast steel joints by experiment or the other methods and extended them to beam-column connections in steel frames. This paper mainly introduced the development of beam-column connection forms, the main problems in joint design, advantages and disadvantages of the joints with various forms, material properties and manufacturing process characteristics of cast steel, advantages of cast steel joints and fasteners, research status and achievements at home and abroad. The results show that compared with traditional connection forms, designers have full freedom to choose the shapes and the sizes, and joints made of cast steel have the best adaptability and changeability in different engineering practice, what’s more, they have no problems with welding residual stress and stress concentration. Compared with other materials, cast steel has more advantages such as flexible application, convenience of connections, small volume, low cost. In a word, cast steel has great research value and application potential in connections of steel structure.

Abstract: The hulushan gulf crossing narrow bridge locates in the southwest of dalian urban of Liaoning province. The mid-span of main bridge bridgings over offing 80 meters and the main bridge adopts 30+100+30 meters flying bird mid-support arch bridge form. There exists typhoon during construction, which makes construction difficult. It is necessary to analyze the safety of formwork scaffold and construct platform because of the complex structure and bad weather. The stability and strength of formwork scaffold and construct platform structure is evaluated through numerical analysis. The result verify that the formwork scaffold and construct platform structure satisfy the demand of code and are designed logically.