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Chitosan is a biodegradable material with good biocompatibility. It can be used in medicine, foodstuff, the chemical industry and heavy metal adsorption. In this study, an exothermic foaming agent (Azodicarbonamide) injection molded was added to polypropylene (PP), maleic anhydride (MA) grafted PP (PPgMA) and Chitosan composites. MA served as a compatibilizer due to the poor bonding between PP and chitosan. This study investigated the effects of the modifier and chitosan loading on the tensile strength, thermal properties and morphology in chemical foam injection-molded PP and PPgMA composites. The results showed that the tensile strength decreased with the addition of chitosan, but Young’s modulus increased with the added chitosan loading. The enhancement was significant for foam injection molding. The cell size decreased and the cell density increased with the addition of chitosan for the PP/PPgMA composites. The thermogravimetric analysis (TGA) results showed that the thermal degradation could be decreased with the addition of chitosan in both the PP and PPgMA composites. The use of foamed chitosan composites will be further investigated in the removal of heavy metal in waste water.

This study investigated the effect of polycaprolactone (PCL) loading (0.5, 1, and 3 wt%) on the morphology, tensile strength, and thermal properties of microcellular injection molded PP/PCL and PPgMA/PCL composites. We used the filler, PCL, that is micro-material in size. Results showed that 0.5 wt% loading of PCL on foamed PP has the largest tensile strength. However, tensile strength was almost similar to that of PPgMA composites. Tensile strength depends on the filler dispersion in the matrix and cell size present on the foamed composites. Good dispersion resulted in good tensile strength. The elongation decreased on PP but increased on PPgMA composites. The highest degradation temperature for PP/PCL and PPgMA/PCL was noted for 3.0 wt% PCL loading and neat PPgMA respectively. Cell size decreased and cell density increased with the addition of PCL into the PP and PPgMA matrix.

The shake table tests presented in this article aims to explore seismic displacement demands for existing reinforced concrete buildings resulting from inelastic torsion associated with different sources of irregularities. Two half-scale seven-story reinforced concrete structures were subjected to unidirectional earthquake excitations on the shake table at the National Center for Research on Earthquake Engineering (NCREE) Tainan laboratory. The specimens reflected structural weaknesses of buildings which collapsed during the Meinong earthquake in Taiwan. This data paper presents an overview of the project as well as the organization of obtained test datasets. The data are available for public use under the Designsafe-CI project “Shake table tests of seven-story reinforced concrete structures with torsional irregularities.”

Polymers reinforced with conducting fibers to achieve electrical conductivity have attracted remarkable attention in several engineering applications, and injection molding provides a cost-effective way for mass production. However, the electrical performance usually varies with the molding conditions. Moreover, high added content of conducting fibers usually results in molding difficulties. In this study, we propose using microcellular (MuCell) injection molding for polypropylene (PP)/carbon fiber (CF, 20, and 30 wt%) composites and hope that the MuCell injection molding process can improve both electrical and mechanical performance as compared with conventional injection molded (CIM) parts under the same CF content. Both molding techniques were also employed with and without gas counter pressure (GCP), and the overall fiber orientation, through-plane electrical conductivity (TPEC), and tensile strength (TS) of the composites were characterized. Based on the various processing technologies, the results can be described in four aspects: (1) Compared with CIM, microcellular foaming significantly influenced the fiber orientation, and the TPECs of the samples with 20 and 30 wt% CF were 18–78 and 5–8 times higher than those of the corresponding samples molded by CIM, respectively; (2) when GCP was employed in the CIM process, the TPEC of the samples with 20 and 30 wt% CF increased by 3 and 2 times, respectively. Similar results were obtained in the case of microcellular injection molding—the TPEC of the 20 and 30 wt% composites increased by 7–74 and 18–32 times, respectively; (3) although microcellular injection molding alone (i.e., without GCP) showed the greatest influence on the randomness of the fiber orientation and the TPEC, the TS of the samples was the lowest due to the uncontrollable foaming cell size and cell size uniformity; (4) in contrast, when GCP was employed in the microcellular foaming process, high TS was obtained, and the TPEC was significantly enhanced. The high foaming quality owing to the GCP implementation improved the randomness of fiber orientation, as well as the electrical and mechanical properties of the composites. Generally speaking, microcellular injection combined with gas counter pressure does provide a promising way to achieve high electrical and mechanical performance for carbon-fiber-added polypropylene composites.

A robot supported by two points on a supporting rough plane is considered. The robot is driven by displacement of internal masses and friction against the surface of the support. The robot body contains two motors that rotate one unbalanced rotor (eccentric weight) and one flywheel. A mathematical model of a plane-parallel robot motion is constructed. Friction is modeled using Coulomb's law. The angular accelerations of the rotor and the flywheel are used as control functions. A technique is proposed for evaluating the coefficient of friction between the robot body and the supporting plane. An algorithm for controlling the motion of the robot body in the desired direction using the obtained value of the coefficient of friction is proposed. An estimate of the implementation time of the algorithm is given. To assess the achievable body speed, a numerical calculation is implemented. The rectilinear translational motion of the body is carried out for the selected set of parameters in a wide range of friction coefficients. It is shown that an increase in friction increases the acceleration efficiency.

Reinforced concrete pile caps are important structural elements transmitting vertical loads from the structure to the ground. The performance of pile caps is complex, with a wide range of s...

Various brands of bamboo crafts created by youths have emerged in Zhushan Township, Taiwan. With the special bamboo materials available in Zhushan Township as their core, these brands have created different types of social innovations through their management, design, and mechanical knowledge. The results indicate the following: (1) The youths advocate for causes such as the preservation of culture, mutually beneficial situations, sustainable local development, and environmentally friendly lifestyles. The youths proposed innovative solutions for these causes, such as establishing a guesthouse, revitalizing unused space, creating opportunities for dialogues, developing bamboo-based environmentally friendly products, and holding local activities; (2) the youths constructed a model for internal cooperation and enhancement, revitalization, and marketing Zhushan Township; (3) the youths advocated for various social values, utilized social capital, and proposed innovative solutions through diversified participation and the creation of new relationships, allowing different communities to generate a group dynamic to resolve social problems and achieve sustainability together. This study aids in the facilitation of sustainable management of township micro-enterprises by innovating products and service modes through social capital and social value. At the same time, local and common social innovation modes are connected to provide a reference for the social innovation of micro-enterprises.

Savonius rotor is considered as an element of mechanical or electromechanical systems. An empirical approach is proposed for describing the aerodynamic torque basing on available data from physical and computational experiments. A stand-alone wind power generator based on the Savonius rotor is examined where the electromechanical interaction is nonlinear. Conditions of existence and attraction properties of equilibrium positions and steady motions in the system are studied. Evolution of steady regimes is analyzed when external load and wind speed change. A wheeled cart driven by Savonius rotor is considered. Questions of existence and stability of steady motions of the system are discussed. Properties of motion of the cart for different wind speeds are studied with consideration of slipping of wheels. It is shown that for certain values of parameters the cart can move upwind and downwind, depending on the wind speed.

In the present study, semi-crystalline polypropylene (PP) and amorphous polystyrene (PS) were adopted as matrix materials. After the exothermic foaming agent azodicarbonamide was added, injection molding was implemented to create samples. The mold flow analysis program Moldex3D was then applied to verify the short-shot results. Three process parameters were adopted, namely injection speed, melt temperature, and mold temperature, three levels were set for each factor in the one-factor-at-a-time experimental design. The macroscopic effects of the factors on the weight, specific weight, and expansion ratios of the samples were investigated to determine foaming efficiency, and their microscopic effects on cell density and diameter were examined using a scanning electron microscope. The process parameters for the exothermic foaming agent were optimized accordingly. Finally, the expansion ratios of the two matrix materials in the optimal process parameter settings were compared. After the experimental database was created, the foaming module of the chemical blowing agents was established by Moldex3D Company. The results indicated that semi-crystalline materials foamed less due to their crystallinity. PP exhibits the highest expansion ratio at low injection speed, a high melt temperature, and a low mold temperature, whereas PS exhibits the highest expansion ratio at high injection speed, a moderate melt temperature, and a low mold temperature.