Effective factors on performance of zeolite based metal catalysts in light hydrocarbon aromatization

Aromatic hydrocarbons are essential compounds, that the presence of which in fuels can improve the octane number. The conversion of the light alkanes to high value aromatics is vital from theoretical and industrial standpoints. Zeolites such as ZSM-5 play an essential role in the aromatization of light alkanes. This paper highlights the mechanism of aromatization of light alkanes such as methane, ethane, propane, butane, and its isomers. Furthermore, effective factors on the aromatization of light alkanes including metal type, crystallinity, acidity, space velocity, pretreatment of zeolites, co-feeding of light hydrocarbon, and operating factors such as temperature have been investigated to determine how a system of zeolite with metals can be useful to reach aromatization with high conversion.

Floquet engineering of carbon nanotubes

The Floquet theory for electrons in carbon nanotubes (CNTs) irradiated by a circularly polarized electromagnetic wave propagating along the CNT axis is developed. It is demonstrated, particularly, that the irradiation opens the gap between the conduction and valence bands of CNTs of metal type and lifts the degeneracy of electron states with mutually opposite angular momenta along the CNT axis. As a consequence, the optically-induced metal-insulator transition and the optical Zeeman effect appear in the CNTs. It follows from the theory that these light-induced phenomena can be observed in the modern experiments.

An Experimental Reproduction Study on Characteristics of Woodblock Printing on Traditional Korean Paper (Hanji)

The history of printing technology in Korea is studied by investigating existing ancient documents and records and comparing accumulated data and knowledge. Cultural property research requires non-destructive testing and observation with the naked eye or aided by a microscope. Researchers’ experience and knowledge are required even though they cannot guarantee the outcome. For ancient documents and records that are presumed to consist of woodblock printing, wood type printing, metal type printing, or their combinations, each researcher draws various opinions and conclusions. This often causes confusion and divides the opinions of ordinary citizens and field specialists. Among them, the criteria for judging ancient documents or books printed using woodblock and metal movable material are ambiguous. Academic research on the development history of printing technology in ancient Korea has been stagnant, and conflicts among researchers have also erupted. Involvement of national investigative agencies not specialized in cultural properties has exacerbated the situation. In this study, we investigated printing characteristics that are likely to serve as more objective judgment criteria by quantitatively analyzing the experiments of retrieving several sheets of Korean paper (Hanji) using a replicated Hunminjeongeum (訓民正音) woodblock and quantitatively analyzing the images of the printed papers. In addition, the validity and questions for the typical phenomena presented as a method for distinguishing between woodblock and metal print are reviewed. We investigated the possibility of developing new objective judgement criteria through quantitative analysis using image analysis and investigating the printing characteristics of Korean paper through a reproduction experiment of woodblock printing.

Failures Related to Castings

The information provided in this article is intended for those individuals who want to determine why a casting component failed to perform its intended purpose. It is also intended to provide insights for potential casting applications so that the likelihood of failure to perform the intended function is decreased. The article addresses factors that may cause failures in castings for each metal type, starting with gray iron and progressing to ductile iron, steel, aluminum, and copper-base alloys. It describes the general root causes of failure attributed to the casting material, production method, and/or design. The article also addresses conditions related to the casting process but not specific to any metal group, including misruns, pour shorts, broken cores, and foundry expertise. The discussion in each casting metal group includes factors concerning defects that can occur specific to the metal group and progress from melting to solidification, casting processing, and finally how the removal of the mold material can affect performance.

Exploitation Characteristics of Teeth Flanks of Gears Regenerated by Three Hard-Facing Procedures

Numerous phenomena that occur during the process of machine parts’ regeneration have a significant impact on the loss of their working ability. Therefore, the properties of the working surfaces of the teeth flanks of repaired gears were analyzed in this research. The hereditary properties of the gear teeth are expressed by the interdependence of their geometric and physical-mechanical-metallurgical parameters created during the technological operations of regeneration of worn teeth by welding/hard-facing. The hard-facing was executed with three filler metal types, namely: combination Inox 18/8/6 + EDur 600, Castolin 2 and UTP 670. The tested properties included geometrical accuracy, microstructure and microhardness. Evaluation of the executed regeneration procedures was done by comparing the mentioned parameters of the regenerated gears and the new ones. The tested gears were not withdrawn from production due to damage, but they were newly manufactured and intentionally damaged gears, made of the same materials, subjected to the same manufacturing process. In this way, all influences except for the considered filler metal type were eliminated. Based on results of the conducted experiments, it was possible to establish the influence of the filler metal type on the surface characteristics of the regenerated gears’ teeth flanks.

Controlling photonic spin Hall effect by a symmetric hyperbolic metamaterial waveguide

We investigate the photonic spin Hall effect (PSHE) in a symmetrical hyperbolic metamaterial (HMM) waveguide, which is constructed as an HMM/metal/HMM sandwich structure. We consider both type {\uppercase\expandafter{\romannumeral 1}} and type {\uppercase\expandafter{\romannumeral 2}} HMM in the study. We confirm that the structure of alternating sub-wavelength of plasma and dielectric or the structure of embedding plasma into a host dielectric matrix can display effective dielectric, effective metal, type {\uppercase\expandafter{\romannumeral 1}} and {\uppercase\expandafter{\romannumeral 2}} HMM under different wavelength ranges and different plasma fill fraction. This enable us to simultaneously realize type {\uppercase\expandafter{\romannumeral 1}} and type {\uppercase\expandafter{\romannumeral 2}} HMM. We show that the reflectivity ration $\vert r_{s}/r_{p} \vert$, directly related to transverse shifts generated by PSHE, greatly depends on the type and the thickness of HMM. Moreover, we find that the horizontal PSHE shifts are enhanced several times, especially in type {\uppercase\expandafter{\romannumeral 1}} structure; while the vertical PSHE shifts are significantly suppressed in both type {\uppercase\expandafter{\romannumeral 1}} and {\uppercase\expandafter{\romannumeral 2}} structure. By making the effect of metal type and thickness analysis, we further show that the impacts of these two factors on PSHE shifts are mainly subject to HMM thickness.