Hydrogen promotion by Co/SiO2@HZSM-5 core-shell catalyst for syngas from plastic waste gasification: The combination of functional materials

In the present work, a core-shell structured Co/SiO₂@HZSM-5 catalyst was prepared for hydrogen production from syngas of plastic waste gasification. The cobalt catalyst was coated with HZSM-5 shell through a hydrothermal process, and the Co/SiO₂@HZSM-5, with different loadings of HZSM-5 (e.g., 10–30 wt %) exhibited excellent activity and durability for dehydrogenation reactions. The amount of HZSM-5 was found to be an important factor for hydrogen production. Temperature-programmed reduction with H₂ and temperature-programmed desorption of ammonia was applied to determine the active site and the acidity of prepared catalyst, respectively. The prepared Co/SiO₂@HZSM-5 was tested through reforming of plastic gasification syngas and shown superior hydrogen production ability (∼90%) and stability (over 15 h). The effects of reduction-oxidation behavior on the catalytic performance were also discussed.     

Hermetic storage for control of common bean weevil,Acanthoscelides obtectus (Say)

This study evaluated hermetic storage as a method of controlling Acanthoscelides obtectus (Coleoptera: Chrysomelidae: Bruchinae) in stored beans. Recently harvested “vermelhinho” cultivar of the common red bean was used, which had already been infested by A. obtectus in the field. Beans with a moisture content of 15.0% wet basis were stored in silo bags (3 kg), plastic bottles (1.5 L), or non-hermetic glass containers (3 L) (control) for 120 days. The packages were stored in an acclimatized chamber at 25 °C with a relative humidity of 70 ± 5%. At time intervals of 0, 30, 60, 90, and 120 days, three packages of each treatment were opened, and analyses were performed to assess the infestation percentage by insect pests, moisture content, density, electrical conductivity, germination percentage, and cooking time. There was no increase in infestation by A. obtectus in the grains stored in the silo bags and plastic bottles during the 120 days of storage; however, there was a significant increase in infestation in the grains in non-hermetic storage (control). The quality of the beans correlated with infestation; it was not altered in the hermetic storage systems and decreased in the control sample. Hermetic storage of common beans is an effective tool in the control of A. obtectus.     

Ductility of polylactide composites reinforced with poly(butylene succinate) nanofibers

Sustainable “green nanocomposites” of polylactide (PLA) and poly(1,4-butylene succinate) (PBS) were obtained by slit die extrusion at low temperature. Dispersed PBS inclusions were sheared and longitudinally deformed with simultaneous cooling in a slot capillary and PBS nanofibers were formed. Shearing of PBS increases nonisothermal crystallization temperature by 30 °C. Tensile deformation was investigated by in-situ experiments in SEM chamber. Dominant deformation mechanism of PLA is crazing, however, there are dormant shear bands formed during slit die extrusion. Pre-existing shear bands are inactive in tensile deformation but contribute to ductility by blocking, initiating and diffusing typical craze growth. PBS nanofibers are spanning PLA craze surfaces and bridging craze gaps when PLA nanofibrils broke at large strain. Straight crazes become undulated because either dormant or new shear bands become activated between crazes. Due to interaction of crazes and shear bands the ductility increases while high strength and stiffness are retained.     

Influence of zirconium content on microstructure and creep properties of Mo–9Si–8B alloys

Mo–Si–B alloys with a molybdenum solid solution accompanied by two intermetallic phases and Mo₅SiB₂ are a prominent example for a potential new high temperature structural material. In this study the influence of 1, 2 and 4 at.% zirconium on microstructure and creep properties of Mo–9Si–8B (at.%) alloys produced by spark plasma sintering is investigated. Creep experiments have been carried out at temperatures of 1100 °C up to 1250 °C in vacuum. The samples exhibit sub-micron grain sizes as small as 450 nm due to the chosen production route. With addition of 1 at.% zirconium, formation of SiO₂ on the grain boundaries can be prevented, thereby enhancing grain boundary strength and creep properties significantly. Moreover ZrO₂ particles also enhance creep resistance of the molybdenum solid solution. Creep deformation is a combination of dislocation creep in the grains including dislocation-particle interaction and grain boundary sliding leading to intergranular fracture surfaces. It is promising to use grain size adjustments in order to balance the creep and oxidation resistance of the investigated material.     

麻布纤维对水泥砂浆裂纹扩展影响分析

为研究麻布纤维对水泥砂浆裂缝扩展的控制效果及实用性,通过试验并结合ANSYS软件模拟,研究了麻布纤维对水泥砂浆裂纹扩展与强度的影响。结果表明:适量麻布纤维对提高水泥浆体的强度及控制裂缝的发展效果显著,具有实际应用价值;不同的麻布纤维掺量对水泥砂浆强度和裂缝的影响效果不同。     

Clairvoyance: A framework to integrate shared displays and mobile computing devices

Supporting formal and informal meetings with digital information and ubiquitous software systems every day becomes increasingly mandatory. These meetings require that the integration of devices participating in the meeting and the information flow among them should be done as seamless as possible to avoid jeopardizing the natural interactions among participants. Trying to contribute to address such a challenge, this article presents a framework that allows devices integration and smooth information flow. This framework, named Clairvoyance, particularly integrates mobile computing devices and large-screen TVs through a mobile ad hoc network, and thus it eases the implementation of shared displays intended to be used in formal and informal meetings. Clairvoyance provides a set of services through an API, which can be used to develop ubiquitous applications that support meetings in particular scenarios. The preliminary evaluation of this framework considered its usage to implement a ubiquitous system that supports social meetings among friends or relatives. According to developers, the framework is easy to use and it provided all required services for such an application. The solution obtained was then utilized by end-users in simulated meetings. The evaluation results indicate that the Clairvoyance services were suitable to support the informal meetings, and that the devices integration and information flow were transparent for the end-users.     

Measurement of binocular disparity in polarized based stereoscopic display by using digital camera

This work presents an image displacement measurement by using a box pattern and the edge spread function analysis in the polarized based stereoscopic displays. The measurement determines to identify three factors (i.e., box size, image displacement, and spatial frequency response (SFR)) from the box patterns. The polarized based stereoscopic displays might sacrifice pixels for producing 3D images, which might produce errors in the image displacement and then affect the depth perception indirectly. Based on the measurement, the errors can be quantified by using the three factors. Owing to the light leakage distorting the edge spread function to obtain an inferior SFR, exactly how light leakage affects the edge spread function can be resolved on the basis of the SFR results, especially at a frequency (1/display pixel) of 1.9 in the case of the horizontal displacement. Light leakage also induces the error of the box height in even and odd intervals of the vertical displacements more than 2 pixels and 0.5 pixels, respectively. The image displacement measurement provides a simple and comprehensive means of evaluating the optical characteristics, disparity, and sharpness of the stereoscopic displays, via the three factors.     

Analysis of the extended stress-based forming limit curve considering the effects of strain path and through-thickness normal stress

In this study, an approach based on the modified Marciniak–Kuczynski (M–K) method for computation of an extended stress-based forming limit curve (FLC) is presented. The extended stress-based FLC is built based on equivalent plastic stress versus mean stress. This curve has some advantages in comparison with the conventional FLC. This new criterion is much more strain path independent than the conventional FLC. The effect of strain path on the predicted extended stress-based FLC is reexamined. For this purpose, two types of pre-straining on the sheet metal have been loaded. Moreover, the plane stress state assumption is not adopted in the current study. The influence of a through-thickness compressive normal stress is also investigated theoretically. The verifications of the theoretical FLCs are performed by using some available published experimental data.     

Influence of the rigidity of the steroid core in the structure of chiral dopants on the temperature dependence of cholesteric short pitch

New chiral compounds of the steroid type, namely, 3-alkanoyl- and 3-alkyl derivatives of 16-arylidene estrone, were synthesized and exhibited high helical twisting power (HTP) in nematic liquid crystals E63 and LC-1289. The peculiarities of the molecular structure of chiral compounds (CCs) and their high degree of chirality were discussed. Quite small concentrations of chiral compounds in both nematic solvents were needed to obtain a short-pitch cholesteric helical macrostructure with the selective light reflection in the visible range of the spectrum. The insignificant temperature dependence of the maximum wavelength of the selective light reflection obtained on the whole cholesteric range for all studied liquid crystalline (LC) systems could be related to relatively rigid molecular structure of the chiral compounds. The cholesteric LC mixtures comprising 3-alkanoyl- and 3-alkyl derivatives of 16-arylidene estrone were characterized by the phase stability and the stability of reflective characteristics in time that makes it possible to consider this series of dopants as appropriate for development of bistable cholesteric reflective LC displays.