Remote robotic system for 3D measurement of concrete damage in tunnel with ground vehicle and manipulator

To ensure the safety of a concrete structure, periodic and accurate inspection for damage is necessary. However, there is a high risk of inaccurate diagnosis of the structure condition because the manual inspection method is dependent on operator experience and subjective judgment. Additionally, in future society, it may become increasingly difficult to maintain high-quality infrastructure, as the number of inspection personnel will also decrease with a decrease in population. For this purpose, the demand for accurate and automated inspection technology is increasing. To meet these issues, in this study, an objective and automated inspection method is proposed by developing an inspection robot and management system. The inspection robot comprises an artificial intelligence sensor, a manipulator, and a ground vehicle; it can autonomously drive inside a tunnel and inspect the damage on concrete surfaces using stereo vision. The management system remotely controls the robot through wireless communication and monitors the inspection status in real time. In addition, damage is automatically restored in three dimensions based on the images, and the physical size of the damage is analyzed with an average relative error of 0.39%. This method is expected to be used as a core technology for unmanned and automated tunnel maintenance in the future.     

材料的重要性

《材料的重要性》是《景观设计理论》的一段节选。《景观设计理论》旨在不使用专业术语或其他领域假说的前提下,结合景观设计过程向学生介绍内在理论思想。《材料的重要性》是本书的五章之一。每一章针对特定理论,解释了其基础和来源,探讨了它对设计的重要性,列举了20—21世纪与其相关的设计案例,整理了该理论的辩论(尤其是有关现代和后现代思想),最后还有相关阅读材料清单和需要学生们思考的问题。本文分为如下3个部分：第一部分,物质性,介绍“辩证唯物主义”“媒介即信息”“物质实践”和“编码”等理论及其在设计中的运用;第二部分,通过“建构表达”“地貌代理人策略”“石材的面层”“材料的暗示”“人造,但不是伪造”等理论,介绍材料的真实性及其在设计中的运用;第三部分,复写理论及应用,包括“剩余物”“复写的展示性”“未来的复写”和“虚构的复写”等内容。     

风景园林与绿色基础设施在城市流域水资源规划中的重要作用

通过绿色基础设施途径,处理美国波士顿北部的马萨诸塞州城市流域的水资源规划问题。从多个尺度为风景园林师提供水资源规划的经验与启发,探究公众对新型绿色基础设施解决方案的态度与偏好,以及公众偏好对于整体规划设计的重要作用。     

Fabrication of nanoporous silicon carbide fibres by thermal treatment

Abstract

Nanoporous silicon carbide fibres were prepared by curing and heat treatment of melt spun polycarbosilane (PCS) fibres. During the curing process, green PCS fibres were thermally oxidised at the temperature between 180 and 220°C and time between 2 and 10 h for cross-linking among the molecule chains in the PCS and controlling the oxygen concentration and distribution. After thermal oxidation, fibres were heat-treated between 1200 and 1600°C for the conversion to SiC phase. About 15–20 wt-% of oxygen was analysed after heat treatment at 1200°C and it can be possible to pyrolyse without melting or deformation of fibre. At a temperature above 1400°C, the uniform distribution of nanopores was observed on the fibre surface, and the size of pores was increased with curing and heating condition. This type of nanoporous SiC fibre is expected to be a good candidate for high temperature catalyst or catalytic supports.     

Enhancement of antireflection property of silicon using nanostructured surface combined with a polymer deposition

Silicon (Si) nanostructures that exhibit a significantly low reflectance in ultraviolet (UV) and visible light wavelength regions are fabricated using a hydrogen etching process. The fabricated Si nanostructures have aperiodic subwavelength structures with pyramid-like morphologies. The detailed morphologies of the nanostructures can be controlled by changing the etching condition. The nanostructured Si exhibited much more reduced reflectance than a flat Si surface: an average reflectance of the nanostructured Si was approximately 6.8% in visible light region and a slight high reflectance of approximately 17% in UV region. The reflectance was further reduced in both UV and visible light region through the deposition of a poly(dimethylsiloxane) layer with a rough surface on the Si nanostructure: the reflectance can be decreased down to 2.5%. The enhancement of the antireflection properties was analyzed with a finite difference time domain simulation method.     

Formation of self-organized Zircaloy-4 oxide nanotubes in organic viscous electrolyte via anodization

This work reports the formation of self-organized Zircaloy-4 (Zr-4) oxide nanotubes in viscous organic ethylene glycol (EG) electrolyte containing a small amount of fluoride salt and deionized (DI) water via an electrochemical anodization. The structure, morphology, and composition of the Zr-4 oxide nanotubes were studied using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), EDX, and XPS. SEM results showed that the length of the nanotubes is approximately 13 μm, and TEM results showed that the inner diameter of the Zr-4 oxide nanotubes is approximately 20 nm with average wall thickness of approximately 7 nm. XRD and selected area electron diffraction pattern (SAED) results confirmed that the as-anodized Zr-4 oxide nanotubes have cubic crystalline structure. Both cubic and monoclinic phases were found after annealing of Zr-4 oxide nanotubes. The tubular structure morphology of Zr-4 oxide nanotubes did not remain intact after annealing which is attributed to the elimination of F species from the annealed nanotubes.     

Simvastatin Attenuates the Oxidative Stress,Endothelial Thrombogenicity and the Inducibility of Atrial Fibrillation in a Rat Model of Ischemic Heart Failure

Increased atrial oxidative stress has an important role in inducing and maintaining atrial fibrillation (AF), and the activation of the small GTPase Rac1 contributes to the oxidative stress. We investigated the relationship of Rac1, atrial endothelial thromboprotective markers and AF inducibility and if simvastatin has a potential beneficial effect on a myocardial infarction (MI)-induced heart failure (HF) rat model. Rats were randomized into three groups (shams, MI group and simvastatin treatment group) and underwent echocardiography, AF induction studies and left atrial (LA) fibrosis analysis. Atrial Rac 1, sodium calcium exchanger (I_NCX), sarcoplasmic reticulum calcium ATPase (SERCA), endothelial nitric oxide synthase (eNOS) and induced nitric oxide synthase (iNOS) were measured. AF inducibility, AF duration and LA fibrosis were significantly higher in the MI group (p < 0.001 vs. sham), which were significantly reduced by simvastatin (p < 0.05 vs. MI). The reduced expressions of atrial eNOS, SERCA, thrombomodulin, tissue factor pathway inhibitor and tissue plasminogen activator in the MI group were significantly improved by simvastatin. Furthermore, the increased expression of atrial iNOS, I_NCX and Rac1 activity were significantly decreased by the simvastatin. Oxidative stress, endothelial dysfunction and thrombogenicity are associated with the promotion of AF in a rat model of ischemic HF. These were associated with increased Rac1 activity, and simvastatin treatment prevents these changes.     

Flavonoids from Machilus japonica Stems and Their Inhibitory Effects on LDL Oxidation

Stems of Machilus japonica were extracted with 80% aqueous methanol (MeOH) and the concentrated extract was successively extracted with ethyl acetate (EtOAc), normal butanol (n-BuOH), and water. Six flavonoids were isolated from the EtOAc fraction: (+)-taxifolin, afzelin, (−)-epicatechin, 5,3''-di-O-methyl-(−)-epicatechin, 5,7,3''-tri-O-methyl-(−)-epicatechin, and 5,7-di-O-methyl-3'',4''-methylenedioxyflavan-3-ol. The chemical structures were identified using spectroscopic data including NMR, mass spectrometry and infrared spectroscopy. This is the first report of isolation of these six compounds from M. japonica. The compounds were evaluated for their diphenyl picryl hydrazinyl scavenging activity and inhibitory effects on low-density lipoprotein oxidation. Compounds 1 and 3–6 exhibited DPPH antioxidant activity equivalent with that of ascorbic acid, with half maximal inhibitory concentration (IC₅₀) values of 0.16, 0.21, 0.17, 0.15 and 0.07 mM, respectively. The activity of compound 1 was similar to the positive control butylated hydroxytoluene, which had an IC₅₀ value of 1.9 µM, while compounds 3 and 5 showed little activity. Compounds 1, 3, and 5 exhibited LDL antioxidant activity with IC₅₀ values of 2.8, 7.1, and 4.6 µM, respectively.     

Effects of the Surface Contact on the Uncertainty in Indentation Yield Strength: Surface Roughness and Angular Misalignment

Metals and Materials International - We suggest a method for accurately estimating the uncertainty of indentation yield strength determined from the modified Meyer relation as a mathematical...     

Inhibitory effect of chloroform on fermentative hydrogen and methane production from lipid-extracted microalgae

To improve the sustainability of microalgae as a bioenergy feedstock, lipid-extracted microalgae (LEM) are often further treated by anaerobic digestion (AD). However, the residual chloroform used for extracting lipids as a solvent could inhibit this process, an aspect that has not been studied to date. In this study, the inhibitory effect of chloroform on H₂ and CH₄ production was investigated by performing batch tests. To prepare the feedstock, Chlorella vulgaris was ultrasonicated and the supernatant was discarded after centrifugation. In case of H₂ production, it was found that the H₂ yield fell to almost half that of the control (15.6 mL H₂/g COD_added) at 100 mg CHCl₃/L. The reason for the decrease of the H₂ yield with the increase of chloroform level was due to the change of metabolites from acetate and butyrate to lactate via a non-hydrogenic reaction. In comparison with H₂ production, a much more severe inhibitory effect of chloroform on CH₄ production was observed. The inhibitor concentration (IC_{30, 60, and 90}) on H₂ production was 138, 319, and 622 mg CHCl₃/L, respectively, while concentrations of 15, 37, and 86 mg CHCl₃/L were obtained on CH₄ production. When the chloroform concentration was ≥25 mg/L on CH₄ production, more than 2 g COD/L of organic acids remained, resulting in a decrease of CH₄ yield. These findings indicate that the residual chloroform in LEM should be seriously considered to prevent possible microbial inhibition when designing a process for additional energy recovery from microalgae via AD.