Applied Mechanics and Materials Vol. 197

Abstract: Based on the theory of artificial neural networks and back propagation algorithm, a model for predicting the settlement of embankment was proposed. Neural networks was proceeded with Matlab program. Combining with the real settlement data of Jieyang highway, the model was trained again and again, and then the parameters of model was calibrated. Comparing the prediction value of model with the observational data based on field measurement, it shows that the accordance of the predicted settlements by the proposed model with the measured data is better. As a branch of nonlinear science, neural network theory has strong practical value and advantages in embankment settlement engineering analysis and prediction, because of its strong ability to learn and its high accuracy to approach any nonlinear function.

Abstract: The increasing of equivalent floor live-loads is used to describe the weakening of ultimate carrying capacity of the structure by analyzing variety of the beam’s ultimate moment and ultimate shearing force and the carrying capacity and stability of the column of steel-frame in fire, the formulas of the beam’s ultimate shearing capacity, the carrying capacity and stability of column and the equivalent floor live-loads have been derived based on these. The variety rules of the carrying capacity of beam and column of the steel-frame with different thickness of the protection layers and the equivalent floor live-load have been analyzed in the example, the results showed that different equivalent floor live-load may be used to analyze the infection of fire temperature to the carrying capacity of structure in the computations of steel-frame in fire according to different time and fire temperatures of structure members, the mechanics computations of structure would be predigested and the variety of ultimate carrying capacity of steel-frame also could be estimated.

Abstract: The present economical conditions on today’s world require specific point of view and policy making in business agencies. In this competitive world to achieve competence, competitive advantages in order to better governance, organizations need to increase their competitive powers through increasing productivity. One of the fundamental approaches to enhance the productivity level is first identifying the organizational complications then finding solution and implementing the solutions. To shed light on recognizing the firm’s complications and recoverable areas in the business agencies the authors were benefited from the concept of critical factors of success and social capital affect on inter-firm relationships then an empirical model by taking advantage of Deming Continue improvement model was presented. In order to verify and validate the performed research the planned model was accomplished in the Iran hydropower plants. Positive and acceptable results were obtained hydropower complications were identified and removed as well, organizations total factors of productivity improved.

Abstract: Superfine, high-purity and well-distributed magnesium aluminate spinel powders were fabricated by controlling alkoxides hydrolysis process. Magnesium aluminate alkoxides were prepared by sol-gel with magnesium, aluminum and n-butyl alcohol as starting materials. Magnesium aluminate spinel powders were fabricated by double alkoxides sintering at 1200 °C for 1h. Controlling hydrolyzing process could obtain the optimum gel time and spinel powders were analyzed by OMEC LS-800 type Laser Particle Size Analyzer. Integrated gel time and particle size, the optimum hydrolyzing parameters are obtained for double metal alkoxides: the concentration of the double metal alkoxides is below 0.3 mol/L, hydrolysis temperature is 20 °C, the molar rate of alkoxides and water is 1: 10 and the mechanism of the hydrolysis is investigated. Nicolet Avatar 360 type FTIR spectrometer shows that acetylacetone and alkoxides can form a stable hexatomic ring which restrains hydrolysis reaction and controls particle size.

Abstract: This paper deals with problems in the coining process for manufacturing surgical slit knife using two-dimensional (2D) and three-dimensional (3D) finite element (FE) simulations. The FE simulations are performed to investigate the material flow, and especially stress distribution on the coining dies. The main objective of this paper is to study the feasibility of a coining process for manufacturing a given geometry of surgical slit knife without forming defects and die failure. Very high stress distribution on the coining dies is found by 2D simulations of the coining process that exceeds the strength limit of the die material. The optimum preform and preforming die geometry are determined by FE simulations in order to reduce the die stress. 3D simulations of the preforming and coining processes are conducted with the optimal design to show that the geometry of the product can be achieved without defects by the coining process.

Abstract: Traditional engineering design and realization typically follows a sequential pattern as described by many research publications such as French, Pahl and Beitz. These design methodologies face challenges when time is essence in product realization lifecycle. In contrast, as the design process of a product evolves，this new method incrementally creates machining feature model and realizes concurrent design feature and machining feature modeling based on an algorithm developed for local feature recognition. In addition, the method accelerated the determination of the area that require to be recognized by utilizing a dynamic link list to record the changing information of topological elements, the design features of the model generated by the feature-based design, processing and feature recognition is generated through feature model.

Abstract: Head injury of pedestrian is the most common and fatal cause of mortality in vehicle-to-pedestrian crash. And the engine hood is most likely to cause harm to pedestrian head. Efforts to improve engine hood design, which minimize the head injury of pedestrian in vehicle-to-pedestrian crash, are becoming more and more important. In this study, an approximate model of hood thickness for three targets: HIC, mass and modality, is established. In order to meet the requirements of lightweight and reducing vibration and noise, approximate models iterate by the NSGA-II genetic optimization algorithm, and select the Pareto optimal solutions for thickness optimization. At last the study re-simulates the collision between pedestrian head and hood to verify the reliability of the obtained optimization results.

Abstract: Recently biofuels derived from biomass have received increased concerns in an attempt to search for sustainable development. The first and second generation biofuels are unsustainable since the growth of these food or non-food crops for biofuel generation will compete for limited arable farmlands, thus increasing the risks on food availability. Microalgal biofuels, known as the third generation biofuels, have the potential for sustainable production in an economically effective manner. The advantages of microalgae as a biofuel feedstock are many, for instance, high photosynthesis efficiency, high oil content and noncompetition with food crop production on farmlands. Microalgae can be employed for the production of biodiesel, bioethanol, biogas, biohydrogen, among others. The integrated biorefinery approach has huge potential to greatly improve the economics of biofuel production from microalgae. However, the production of microalgal biofuels is still at pre-commercial stages since it is expensive to produce substantial amount of biofuels at a large scale. Despite this, microalgae are still the most promising and best feedstock available for the biofuels. Biotechnology advances including genetic and metabolic engineering, well-funded R&D researches and policy support can make microalgal biofuels have a bright future.

Abstract: Laser cladding utilizes a laser as energy source to apply a layer of a desired material onto a substrate. As a complex thermal-mechanical process, laser cladding is not quite understood yet. In this paper, effects of process variables on temperature variation during laser cladding are investigated with finite element method. The powder feeding during cladding is taken into account by using the element’s functions of “death” and “birth”. This makes the analysis more accurately. The analysis results show that the maximum temperature at the melting pool during cladding is directly proportional to the laser power and preheated temperature. The maximum cooling rate at the melting pool is inversely proportional to them. Increasing the preheated temperature can decrease the cooling rate of the clayed layer effectively. Increasing the laser power can also decrease the cooling rate, but the effect is not obvious.

Abstract: This paper presents a strategy for the maximization of the output power of photovoltaic (PV) systems under non homogeneous solar irradiation by means of automatic reconfiguration of the PV arrays layout. The innovation of the proposed approach is the employment of a simple Dynamic Electrical Scheme (DES), allowing a large number of possible modules interconnection, to be installed between the PV generator and the inverter. The models of the PV generator and of the DES have been realized and simulated with Simulink (Dynamic System Simulation for MATLAB). The attained experimental results appear to be quite interesting in terms of the attainable benefit in power and thus energy terms. The limited calculation times of the reconfiguration algorithm allows the application of the DES for the real time adaptation of the configuration to the changing weather conditions or other causes of non-uniform solar irradiation. Moreover, the results confirm that, in case of non uniform solar irradiation, this approach allows to attain considerably much better results than those attainable with a static configuration.