Do universal adhesives provide the benefits from double-application or an extra bonding layer in composite repair?

This study aimed to determine whether the application of extra hydrophobic resin (EHR) or double layer (DL) improves microtensile bond strength (μTBS) of two universal adhesives to composite resin. Composite blocks were fabricated and exposed to thermal cycles. The specimens were horizontally sectioned into two halves. Scotch Bond Universal (SBU) and Clearfil S3 Bond Universal (CSBU) were applied to the ground composite surface according to the manufacturers' instructions, or with DL application or EHR application. The repair composite was incrementally placed to bonded planes. Composite sticks were achieved and tensed with a universal testing machine, followed by examining the fracture surfaces by a scanning electron microscope. Data were evaluated by Weibull analysis (shape and scale [σ_θ and σ_0.10] parameters) using the maximum likelihood method. The σ_θ and σ_0.10, respectively, estimate strength at 63.2 and 10% probability of failure. Shape parameter values showed significant differences among treatments. DL application of CSBU did not affect μTBS values at σ_θ of failure but caused to decrease μTBS values at σ_0.10 of failure. DL application of SBU reduced μTBS values at σ_θ of failure. DL or EHR coating did not improve μTBS of SBU. EHR application increased μTBS of CSBU, whereas DL application did not benefit.     

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...     

Electrochemical,continuous-flow determination of p-benzoquinone on a gold nanoparticles poly(propylene-co-imidazole) modified gold electrode

A novel continuous flow biosensor based on gold nanoparticles and poly(propylene-co-imidazole) was developed for the online determination of p-benzoquinone. The amperometric response was measured as a function of p-benzoquinone concentration at an applied potential of ?50 mV. The hydrogen peroxide concentration was optimized and fixed at 1 mM in samples. The mass transfer resistance of the copolymer film was minimized, and the flow cell was regenerated quickly at 1 mL/min. The resulting device provided good analytical performance based on a linear dynamic range from 5–100 µM, a short response time of 3 s, a detection limit of 3.3 µM, excellent repeatability with a relative standard deviation of 0.82%, long-term stability of 95% after four weeks, and an accuracy of 105%. The gold nanoparticles enhanced the electron transfer rate on the electrode. The apparent Michaelis-Menten constant was 4 mM, showing that the enzyme retained catalytic specificity and provided high activity for p-benzoquinone.     

Incidence of Fusarium verticillioides and levels of fumonisin B1 and B2 in corn in Turkey

A total of 100 corn samples conforming collected from local farmers and markets from districts of Samsun, Turkey, were analyzed for Fusarium verticillioides, fumonisin B₁ and B₂ contamination. Ninety-three corn samples were found to contain F. verticillioides, 52 samples fumonisin B₁, and 25 samples fumonisin B₂. Fumonisin B₁ contamination ranged from 0.05 to 25.72 mg/kg and B₂ from 0.05 to 5.7 mg/kg, respectively. This figure indicated widespread contamination of fumonisin B₁ and B₂ in maize grown in different areas of Samsun, Turkey.     

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.     

A Green Chemical Synthesis and Characterization of Mn3O4 nanoparticles

Mn₃O₄ nanoparticles were synthesized via an ionic liquid (IL) assisted process at room temperature, which is rather difficult to achieve by other techniques. The synthesized product was characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetry (TG), and vibrating sample magnetometry (VSM). The prepared material showed a high purity, while crystallite size and particle size agree well with each other, 17±2 and 19±3?nm, respectively, revealing nearly single crystalline character of nanoparticles. The product contains 4?wt% of adsorbed water and ionic liquid. This method provides a facile, one-step, and low-cost route for the synthesis of nanostructures of metal oxides. In addition, [BMIM]BF₄ could be collected and reused for subsequent reactions.