Applied Mechanics and Materials Vol. 472

Abstract: This paper presents the results of the characterization of photovoltaic modules after 20 years of outdoor exposure, and 10 years of operation in Brazil. Several samples of the installed modules were sent to CIEMAT laboratories in Madrid (Spain), where visual inspection, IR characterization, analysis of the chemical composition of the modules, and electrical characterization was performed. I-V curves were measured indoors with solar simulator, and main curve parameters were compared to those obtained from an equivalent module without external exposure. The effect of dust and dirt was evaluated. Series and shunt resistance were calculated, relating these values with the power losses and the visual defects.

Abstract: T Developing a suitable mining safety audition index evaluation system for China that can reflect mining safety production characteristics has great significance to evaluate safety production conditions correctly. The architectural development of mining safety audition index evaluation system should follow the principles of importance, responsibilities, conciseness, relativity, dynamics and territoriality. Development of mining safety audition index evaluation system should refer to the index system positioning and evaluation weighing allocation under these principles. The indexing system should correspond to the main contents of mining safety audition.

Abstract: In emergencies such as fire, pedestrian evacuation for bad visibility is significantly different to the evacuation for normal visibility. In the novel evacuation model, the strategies of pedestrian evacuation and the moving rules are proposed. Then the formulas of the evacuation time are achieved and the time ratio is 0.63. More, using the programming language, pedestrian evacuation is simulated and reproduced. The studies shows that the proposed evacuation model can well reflect the process of pedestrian evacuation; and the evacuation signs of reasonable design can significantly optimize the process. The calculation results also show that the ratio of evacuation time between considering evacuation signs and no evacuation signs is close to 0.63 that is the theoretical results.

Abstract: According to deploying motion principle analysis of its truss element of space cable-strut deployable articulated mast, the mechanical model of deploying process is established. From the perspective of performance function which is satisfied by truss element deploying motion, the reliability model of deploying motion is set up. By utilizing FOSM method, deploying motion reliability is analyzed and solved. The research above provides the basis for mechanism reliability prediction and an effective method to calculate degree of reliability for other space mechanisms..

Abstract: The electrochemical properties of hard carbon (HC) have been investigated for use as negative electrode for lithium ion capacitors. The HC electrode was characterized by scanning electron microscope (SEM) method. The HC negative electrode was galvanostatically prelithiated at 0.1C for three cycles between 0.05-2 V. The LIC with activated carbon and HC electrodes was characterized by cyclic voltammetric analysis at the scan rate of 0.1 mV s^-1 with different voltage ranges. The rate capability of the LIC was tested up to 100C and the retention is 54 %. The cycle performance is retained up to 86% at 50C and 80% at 100C even after 10,000 cycles. The results indicate that hard carbon is suitable as negative electrode materials for high power energy applications.

Abstract: Distillation and GC-MS were employed to analysis the coal tar of low-temperature pyrolysis of lignite briquette by contrasting with standards: the fraction below 340°C in the tar distillates of brown coal tar accounted for 83.30% and the other greater than 340°C is pitch accounted for 16.32%. 34.00% of coal tar are hydrocarbons which are mainly consisted of fat aliphatic hydrocarbon and include few alkene and cycloparaffins. The content of phenolic compounds in coal tar, mainly comes from the fraction below 210°C, is 11.68%. 16.86% of coal tar is aromatic compounds which are mainly composed of substitutive derivative of polyalkylbenzene distributing in all kinds of fractions; and a small amount of aromatic compounds which is concentrated in the fraction below 300°C. The content of oxygen-containing, nitrogen-containing and heterocyclic compounds is 4.47%, 0.57%, 2.11%, respectively.

Abstract: Sulfidation-magnetic roasting process was used to treat tin-bearing iron ore of hematite to recovery iron resources. The results of thermodynamics analysis of the roasting reaction trait showed that, when CO concentration was lower than 11.43% at temperature higher than 873K, SnO2 and Fe2O3 could be selectively reduced to SnO and Fe3O4, respectively. FeS2 would be decomposed into FeS and S2 during the roasting process, and the S2 sulfidation effect was stronger than FeS. After roasting, the main iron phase of the minerals was changed into magnetite from hematite and then the iron could be recovered through the magnetic separation. This method provides a new method for the recovery of iron from tin-bearing iron ore of hematite.

Abstract: A novel series of brush-like amphiphilic statistical tripolymers were designed and prepared by polymerization of amphiphilic macromonomer 2-(acrylamido)-dodecane sulfonic acid (AMC₁₂S, 10 to 90 mol %), with hindrance units sodium p-styrenesulfonate (SSS, 0 to 5 mol %), and 2-(acrylamido)- 2-methylpro-panesulfonic acid (AMPS). The self-assembly behaviors of these tripolymers were investigated using steady-state fluorescence, and the increase of amphiphilic units results in a decrease of microdomain polarity and polymer concentrations for assembly, while the increase of hindrance units leads little change of microdomain polarity.

Abstract: Biaxial pre-stretching is implemented by bulge forming model. After engraved circular grids on new quenching blank, the specimen is biaxially pre-stretching formed. We use JGX-2 Engineering Microscope to measure principal pre-stretching points with 1.5%-3.1% elongation, which are in plane strain state. Hardness is measured by GYZJ 934-1 type Barcol Hardness and microstructures are observed by JEM-200CX Transmission Electron Microscope. The result shows that the influence on tensile strength of biaxial pre-stretching for new quenching state specimen is not big; however, it is the principal pre-stretching quantity 1.75% that improves microstructure and hardness.

Abstract: The joints of magnesium alloy plate with 4 mm thickness was successfully welded by friction stir welding, and the characteristics in microstructure and microhardness of joints after heat treatment were investigated. The results indicate that the tensile strength of as welded joint exceeds 220 MPa, nearly 83% strength of basic metals. During heat treatment, the grains in nugget zone grow gradually, while the grain recrystallization was occurred in heat affected zone and basic metal zone when the temperature is 150°C. As the temperature increases continuously, the grains will grow obviously. The average microhardness of joint will increase and reaches a maximum of 73 Hv at 250°C, and then will decrease sharply with increase of heat treatment temperature.