Elaboration and Characterization of Composite Materials Reinforced by Papaya Trunk Fibers (<i>Carica papaya</i>) and Particles of the Hulls of the Kernels of the Winged Fruits (<i>Canarium schweinfurthii</i>) with Polyester Matrix

In this work we determine the physical and mechanical properties of local composites reinforced with papaya trunk fibers (FTP) on one hand and particles of the hulls of the kernels of the garlic (PCNFA) in the other hand. The samples are produced according to BSI 2782 standards;by combining fibers and untreated to polyester matrix following the contact molding method. We notice that the long fibers of papaya trunks improve the tensile/compression characteristics of composites by 45.44% compared to pure polyester;while the short fibers improve the flexural strength of composites by 62.30% compared to pure polyester. Furthermore, adding fibers decreases the density of the final composite material and the rate of water absorption increases with the size of the fibers. As regards composite materials with particle reinforcement from the cores of the winged fruits, the particle size (fine ≤ 800 μm and large ≤ 1.6 mm) has no influence on the Young’s modulus and on the rate of water absorption. On the other hand, fine particles improve the flexural strength of composite materials by 53.08% compared to pure polyester;fine particles increase the density by 19% compared to the density of pure polyester.

Optimization of resistance spot brazing process parameters in AHSS and AISI 304 stainless steel joint using filler metal

The aim of this research study was to determine optimal resistance spot brazing parameters for joining between AHSS and AISI 304 stainless steel by using filler metal. The key parameters investigated in this study consist of the brazing current, electrode pressure and brazing time. The Taguchi method was applied to the design of experiments. Signal-to-Noise ratio was introduced in the study to identify optimal levels from the process where input parameters yield increased shear strength. Brazing was thus implemented with 5,000A brazing current, 0.70 MPa electrode pressure, and 1.50s brazing time. The maximum shear strength obtained was 54.31 N·mm^-2 in accordance with input parameter settings. In addition, Cu-rich phase and Ag0.4Fe0.6 intermetallic phases were found at the interface zone.

Mechanical Properties of a Wood Flour-PET Composite Through Computational Homogenisation

This work proposes to study the effective elastic properties(EEP)of a wood-plastic composite(WPC)made from polyethylene terephthalate(PET)and Chilean Radiate pine’s wood our,using nite element simulations of a representative volume element(RVE)with periodic boundary conditions.Simulations are validated through a static 3-point bending test,with specimens obtained by extruding and injection.The effect of different weight fractions,space orientations and sizes of particles are here examined.Numerical predictions are empirically conrmed in the sense that composites with more wood our content and bigger size,have higher elastic modulus.However,these results are very sensitive to the orientation of particles.Voigt and Reuss mean-eld homogenisation approaches are also given as upper and lower limits.Experimental tests evidence that exural strengths and ultimate tensile elongations decrease respect to 100%PET,but these properties can be enhanced considering particle-size distributions instead of a xed size of wood our.

合成纳米ZrO_2粉体对水泥强度性能的影响

用低温强碱合成法制得的纳米ZrO2粉体具有小尺寸和量子尺寸效应,产生准相变.把这种粉体适量掺入水泥中,不仅会产生纳米诱导水化效应,形成生长良好的水化产物,而且还能起到填隙和桥联作用,改善水化产物结构,降低水泥石气孔率,提高抗压强度和抗渗性.

Performance evaluation on field synergy and composite regeneration by coupling cerium-based additive and microwave for a diesel particulate filter

In order to reveal the mechanics of composite regeneration by coupling cerium-based additive and microwave for a diesel particulate filter, a composite regeneration model by coupling cerium-based additive and microwave for a diesel particulate filter was established based on field synergy theory. Performance evaluation on field synergy and composite regeneration of the diesel particulate filter was conducted by using the vortex crushing combustion and field synergy mathematical models. The results show that the peak temperature of the particulate filter body reaches 1180-1190 K when the regeneration time is 175 s, and there are optimal coordination degree between the velocity vector and temperature gradient of the filter body and the maximum ratio0.56-0.60 of the best burning regeneration region is obtained. Accordingly, the largest regeneration combustion rate inside the particulate filter body and the highest regeneration efficiency at the moment are achieved.

Social capital and health literacy in Taiwan

The argument of this study is that social capital is a key factor of health literacy. Data came from an island-wide sample. Position generator was adopted to measure social capital. A regression model is constructed to test the social capital which is known as a robust predictor of health literacy after controlling gender, age, education, income, and health communication ability. The results reveal that female, higher education, and better health communication ability are also correlated with health literacy. Implications for public health are discussed.

Aquifer parameter identification by the best chromosome clone plus younger generation chromosome prepotency genetic algorithm

This paper developed an improved combinatorial method called the best chromosome clone plus younger generation chromosome prepotency genetic algorithm （BCC-YGCP-GA） to evaluate aquifer parameters. This method is based on a decimal simple genetic algorithm （SGA）. A synthetic example for unsteady-state flow in a two-dimensional, inhomogeneous, confined aquifer containing three hydraulically distinct zones, is used to develop data to test the model. The simulation utilizes SGA and BCC-YGCP-GA coupled to the finite element method to identify the mean zonal hydraulic conductivities, and storage coefficients of the three-compartment model. For this geometrically simple model, used as a prototype of more complex systems, the SGA does not reach convergence within 100 generations. Conversely, the convergence rate of the BCC-YGCD-GA model is very fast. The objective function value calculated by BCC-YGCD-GA is reduced to 1/1 O00th of the starting value within 100 generations, and the hydraulic conductivity and storage of three zones are within a few percent of the “true” values of the ideal model, highlighting the power of the method for aquifer parameterization.

Evolution of Intermetallic Compounds between Sn-0.3Ag-0.7Cu Low-silver Lead-free Solder and Cu Substrate during Thermal Aging

The growth, transformation, and lattice structure of intermetallic compounds formed between Sn-0.3Ag-0.7Cu lead-free solder and copper substrate were investigated. Dip soldering was used to initiate the reaction between the solder and substrate. An r/-Cu6Sn5 intermetallic phase possessing a hexagonal lattice structure was found at the as-soldered interface. Thermal aging at a number of conditions resulted in the formation of a CuaSn intermetallic phase between the Cu6Sn5 layer and the copper substrate, e-Cu3Sn with an orthorhombic lattice structure was found together with hexagonal CusSn. Subsequently, the activation energies of the intermetallic phases were calculated and compared to results obtained from the literature. The comparison showed that good agreement existed between the findings from this study and literature data within a similar temperature range.

Using a simulation software to perform energy and exergy analyses of the sulfur-iodine thermochemical process

The objective of this work is to demonstrate the utilization of the power of simulation tools to perform an exergy analysis of a process.Exergy analysis,being a new and useful thermodynamics tool,will be applied to one of the newest research fields in hydrogen production.One of the many advantages of computer simulation is elimination of the need to construct a pilot plant.Presently,extensive research is underway to come up with the production and use of clean fuels.The research entails performing pilot studies and proof of concept experiments using validated models.The research is further extended to various analyses such as safety,economic sustainability and energy efficiency of the processes involved.The production of hydrogen through thermochemical water splitting processes is one of the newest technologies and is expected to compete with the existing technologies.Among a wide range of thermochemical cycles,the sulfur-iodine(SI)thermochemical cycle process has been proposed as a promising technology for the production of hydrogen.In this research,we demonstrate how a commercial simulator can be used to perform an energy and exergy analysis of the SI water splitting process.Using a commercial simulator,a process flowsheet is developed based on research findings presented by other authors and an energy-exergy analysis is carried out on the process.The method of energy–exergy analysis used in this presentation indicates that an energy and exergy efficiency of 17%and 24%can be attained,respectively,in the conceptual design of the SI cycle.