Antioxidant activity of stem and root extracts of Rhubarb (Rheum ribes): An edible medicinal plant

The antioxidant activity of chloroform and methanol extract of roots and stems of Rhubarb (Rheum ribes L.), which are used for medicinal purposes and also its fresh stems and petioles are consumed as vegetable, was studied. The antioxidant potential of both extracts of roots and stems were evaluated using different antioxidant tests, namely total antioxidant (lipid peroxidation inhibition activity), DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging, superoxide anion radical scavenging, ferric reducing power, and cupric reducing power (CUPRAC), and metal chelating activities. Total antioxidant activity was also measured according to the β-carotene bleaching method, and all four extracts exhibited stronger activity than known standards, namely butylated hydroxytoluene (BHT) and α-tocopherol. Particularly, higher activity was exhibited by roots with 93.1% and 84.1% inhibitions of chloroform and methanol extracts, while 82.2% and 82.0% inhibitions by stem extracts, respectively. However, both methanol extracts exhibited higher DPPH radical scavenging activity than the corresponding chloroform extracts, moreover, methanol extract of the stems showed better activity than BHT. In addition, both root extracts showed more potent superoxide anion radical scavenging activity than BHT, and comparable with well known radical scavenger l-ascorbic acid. Except chloroform extract of the roots, the other three extracts exhibited better metal chelating activity than quercetin. Also, total phenolic and flavonoid contents in both extracts of the roots and stems of R. ribes were determined as pyrocatechol and quercetin equivalents, respectively.     

Investigation of H2S gas sensing performance of Ni:WO3 films at room temperature: nickel precursor effect

Journal of Materials Science: Materials in Electronics - In this work, pure and nickel-doped WO3 films were produced by chemical bath deposition on In-doped SnO2 (ITO) substrates without annealing...     

Mitigating insider threat by profiling users based on mouse usage pattern: ensemble learning and frequency domain analysis

International Journal of Information Security - Exploring novel security layers in academia and industry is always a concern due to the types of malware developing currently. Adding a widely...     

Advanced Visualization and Accessibility to Heterogeneous Monitoring Data

Structural health monitoring (SHM) is a promising tool for better management of infrastructure. However, failure to manage large amounts of SHM data properly is a big barrier for its widespread application. Data management is especially challenging when heterogeneous data are involved and combined with camera images. Various sensors based on different technologies can measure many parameters such as strain, tilt, weather, etc., whereas live cameras can visualize traffic response. In addition, all the data streams can be registered both statically and dynamically. Data management is even more complex if multiple users access the data and have diverse backgrounds and interests (e.g., the owner/manager of the structure, operator, responsible engineer, and academic). In this article, general principles for SHM data management are researched, established, and proposed by the authors, and an original solution for data management based on these principles is presented. For validation purposes, the proposed principles were implemented in novel data management software and applied to a signature bridge. Feedback from interested groups including the managers, operators, engineers of record, and academics is used for validation. Thus, this article details the researched and proposed accessibility and visualization principles, and conceptual development of novel solution for data management, which combines computer science, internet omnipresence, and structural engineering.     

新型铝锭堆垛机传动系统耦合振动计算

介绍了本单位新研制开发的高效铝锭堆垛机翻转装置,并针对其传动系统结构特点,考虑直齿圆柱齿轮耦合作用,利用整体传递—Riccati矩阵法,对翻转装置传动系统进行了固有频率计算及振型分析,得到了系统前3阶固有频率和该系统的振型,为提高翻转装置传动平稳性进行结构动态优化设计、进一步完善新设备提供了理论依据。     

Impact and post impact behavior of layer fabric composites

In this study, the effect of impact and post impact behavior of E-glass/epoxy composite plates having different layer fabrics were investigated by considering energy profile diagram and the related load–deflection curves. Different impact energies (5 J–60 J)were subjected to the plates consisting of eight layers of plain weave (1D), double (2D) and triple (3D) layer fabrics. The impact tests were continued until complete perforation of layer fabrics. The damage modes and damage processes of layer fabrics under varied impact energies were also discussed. At the end of the impact tests, the damaged samples were mounted into a compression apparatus to determine the Compression After Impact (CAI) strength of layer fabric samples. The results of these impact and post impact tests showed that contact force occurring between the impactor and the composite specimen increased and the CAI strength reduced by increasing the impact energy. The objective of this study was to determine the perforation threshold of E-glass/epoxy composite plates having different layer fabrics as plain weave (1D), double (2D), and triple (3D) layer fabrics.     

Promise and Barriers to Technology Enabled and Open Project Team Collaboration

In today’s world, construction projects require the collaboration of several parties who work independently for a shared purpose, sometimes across space and time, and most of the time across organizational boundaries. Working with a wide diversity of knowledge and skills brings a broad range of viewpoints and expertise to the construction projects. In design and construction, organizations depend on information technology to execute their specific well-defined tasks to make construction projects possible. Technology is used either for executing these tasks more efficiently, or for doing things that were not possible before. Nevertheless, despite the potential positive contribution of these tools to the design and construction processes and organizations, barriers still exist for achieving success. This paper presents potential benefits of technology enabled and open project team collaboration with a case study example and outlines cultural and legal barriers to its widespread adoption by the construction industry.     

A New Approach to H-Infinity Control for Grid-Connected Inverters in Photovoltaic Generation Systems

Abstract

The present study investigates the stability problem of the grid-connected inverters (GCIs) for possible variations in grid impedance. A new type of H∞ control method is proposed for the current control loop of inverters, where the third weighting function is determined using the game theory. The proposed method is applied to the GCI in a photovoltaic system and its response to variations in grid impedance is investigated. Computer simulations conducted for comparison of H∞ and PI controller indicate the effectiveness of the proposed control algorithm. Simulation results also show that the proposed algorithm significantly outperforms the PI controller under the conditions of varying grid impedance.     

Flexural fatigue damage analyses of recycled rubber‐modified epoxy‐based composites reinforced with alumina fibres

Manufacturers have been working towards finding clean and cost‐efficient solutions by utilizing recycled materials to produce new components. Recycled rubber is one such material widely used in aeronautic and automotive industries. In this study, fresh scrap ethylene‐propylene‐diene‐monomer (EPDM) rubber is mixed with epoxy to manufacture novel composites with the addition of alumina (Al₂O₃) fibres. These composites can potentially be used to manufacture components subjected to cyclic loading, and to ensure reliability of such components, fatigue behaviour of these composites should be evaluated. This article describes the manufacturing of recycled rubber‐modified epoxy‐based ternary composites and their fatigue behaviour as well as toughening mechanisms. Dynamic mechanical analysis (DMA) was performed to determine thermomechanical properties. Three‐point bending and flexural fatigue tests and Shore D hardness measurements were carried out to determine mechanical properties. After static/fatigue fracture, fracture surfaces were observed with scanning electron microscope (SEM) to determine toughening mechanisms in these composites.