Structural vibrations caused by a flowing fluid. Whenever a structure is exposed to a flowing fluid,…

Flow-induced vibration

Owing to the fast development of wireless information technologies at the high-frequency range, the electromagnetic interference problem has been of increasing significance and attracting global attention. One key solution for this problem is to develop materials that are able to attenuate the unwanted electromagnetic waves. The desired properties of these materials include low reflection loss value, wide attenuation band, light weight, and low cost. This review gives a brief introduction to graphene-based composites and their electromagnetic absorption properties. The ultimate goal of these graphene absorbers is to achieve a broader effective absorption frequency bandwidth (fE) at a thin coating thickness (d). Representative and popular composite designs, synthesis methods, and electromagnetic energy attenuation mechanisms are summarized in detail. The two key factors, impedance matching behavior and attenuation ability, that determine the electromagnetic behavior of graphene-based materials are given particular attention in this article.

A brief introduction to the fabrication and synthesis of graphene based composites for the realization of electromagnetic absorbing materials

In this work, n–p heterostructure SnO2/BiOI photocatalyst was successfully fabricated through a facile chemical bath method. The photocatalysts was applied to minimize antibiotic oxytetracycline hydrochloride (OTTCH) and methyl orange (MO) under visible light irradiation. SnO2/BiOI composite exhibited excellent photocatalytic performance for the refractory pollutant OTTCH and MO decomposition. The sample of 30 wt % SnO2/BiOI possessed the best photocatalytic performance in all the obtained catalysts. Several reaction parameters affecting OTTCH degradation such as initial concentration, ion species, and concentration were investigated systematically. The optical and electrical properties of materials demonstrate that the transfer rate of electron–hole pairs dramatically improve though forming an n–p junction in SnO2/BiOI hybrid. Moreover, the energy band alignments of SnO2/BiOI junction were confirmed via combining DRS and XPS analysis, which provided strong support for the proposed mechanism. This work co...

Fabrication of SnO2 Nanopaticles/BiOI n–p Heterostructure for Wider Spectrum Visible-Light Photocatalytic Degradation of Antibiotic Oxytetracycline Hydrochloride

Photocatalytic water splitting is attracting enormous interest for the storage of solar energy but no practical method has yet been identified. In the past decades, various systems have been developed but most of them suffer from low activities, a narrow range of absorption and poor quantum efficiencies (Q.E.) due to fast recombination of charge carriers. Here we report a dramatic suppression of electron-hole pair recombination on the surface of N-doped TiO2 based nanocatalysts under enhanced concentrations of H+ and OH−, and local electric field polarization of a MgO (111) support during photolysis of water at elevated temperatures. Thus, a broad optical absorption is seen, producing O2 and H2 in a 1:2 molar ratio with a H2 evolution rate of over 11,000 μmol g−1 h−1 without any sacrificial reagents at 270 °C. An exceptional range of Q.E. from 81.8% at 437 nm to 3.2% at 1000 nm is also reported. Chemical fuels, produced from light, afford an alternative to fossil fuel, but conversion materials suffer from low photon-to-fuel efficiencies. Here, authors incorporate gold/N-doped TiO2 on MgO surfaces and show enhanced photocatalytic water splitting performances at elevated temperatures.

/pdf/photocatalytic-water-splitting-by-n-tio2-on-mgo-111-with-voc3zw5zsp.pdf

Photocatalytic water splitting by N-TiO2 on MgO (111) with exceptional quantum efficiencies at elevated temperatures

TiO2-based powder materials have been widely studied as efficient photocatalysts for water splitting due to their low cost, photo-responsivity, earthly abundance, chemical and thermal stability, etc. In particular, the recent breakthrough of nitrogen-doped TiO2, which enhances the presence of structural defects and dopant impurities at elevated temperatures, exhibits an impressive visible-light absorption for photocatalytic activity. Although their electronic and optical properties have been extensively studied, the structure-activity relationship and photocatalytic mechanism remain ambiguous. Herein, we report an in-depth structural study of rutile, anatase and mixed phases (commercial P25) with and without nitrogen-doping by variable-temperature synchrotron X-ray powder diffraction. We report that an unusual anisotropic thermal expansion of the anatase phase can reveal the intimate relationship between sub-surface oxygen vacancies, nitrogen-doping level and photocatalytic activity. For highly doped anatase, a new cubic titanium oxynitride phase is also identified which provides important information on the fundamental shift in absorption wavelength, leading to excellent photocatalysis using visible light. Nitrogen-doped TiO2 exhibits improved photocatalytic water-splitting activity partially due to enhanced oxygen vacancy formation. Here, authors demonstrate the temperature-dependent lattice distortion of oxygen vacancies, and identify the presence of a titanium oxynitride phase in high activity catalysts.

/pdf/characterisation-of-oxygen-defects-and-nitrogen-impurities-15nxtk5njb.pdf

Characterisation of oxygen defects and nitrogen impurities in TiO2 photocatalysts using variable-temperature X-ray powder diffraction.

We report the enhanced photocatalytic activity of TiO2 by the surface decoration of CoO nanoparticles to degrade paraoxon. The CoO nanoparticles are precipitated in situ during heat treatments of Co doped amorphous TiO2 and enhance the degradation by 11–24 times that of pure TiO2 or Rh2O3–TiO2 or the oxide nanoparticles under white light (natural sunlight and fluorescence light). The enhanced activity is a combined result of visible light absorption by CoO and effective electron-hole separation at the CoO–TiO2 interfaces.

/pdf/environmentally-effective-photocatalyst-coo-tio2-synthesized-1o5glvujbd.pdf

Environmentally effective photocatalyst CoO-TiO2 synthesized by thermal precipitation of Co in amorphous TiO2

Detection and location of OP-degrading activity: A model to integrate education and research.

Flow Induced Vibration (FIV) is one of the important phenomena that contribute to failure of subsea piping components. This paper addresses a detailed methodology to analyze the structural response caused by unsteady multiphase flow within a pipe. This fluid-structure interaction (FSI) study was conducted in a two-bend model of a rigid M-shaped jumper to estimate the stresses and pressure fluctuations and determine the level of risk of failure.Initially, a risk assessment method was carried out to determine the likelihood of failure (LOF) due to flow induced turbulence. Following the screening method, a detailed “two-way coupling” FSI study is recommended. Coupling the Finite Element Analysis (FEA) program with the Computational Fluid Dynamics (CFD) program allows to perform the following assessments:• Strength check (Allowable stress);• Fatigue analysis, and;• Engineering criticality assessment of welds.The two-way coupling analysis also compares the structural natural frequencies to the slug frequencies. Depending on the percentage difference between the two frequencies, a conclusion can be drawn in terms of level of risk and address whether assessing FIV fatigue damage should be required for future examination.Copyright © 2012 by ASME

Detailed FSI Analysis Methodology for Subsea Piping Components

Flow Induced Vibration (FIV) is one of the important phenomena that contribute to failure of jumpers. A computational study was developed to analyze vibrations caused by slug flow in a rigid M-shaped jumper and to estimate the potential effects on its fatigue life. This fluidstructure interaction (FSI) research was conducted in a two-bend model jumper to determine the stresses and pressure fluctuations and predict its response due to the unsteady multiphase flow. A six-bend (whole) jumper simulation was also performed to analyze flow parameters and pressure fluctuations of an original jumper design. Initially, a risk assessment method was carried out to determine the likelihood of failure (LOF) due to flow induced turbulence. After the screening method, a more detailed FSI analysis of piping vibration and response is recommended, specifically “two-way coupling”. This FSI study couples the Finite Element Analysis (FEA) model with the Computational Fluid Dynamics (CFD) model to compare the structural natural frequencies with the slug frequencies and consequently obtain the stress range for fatigue analysis. A conclusion can be drawn that whether assessing FIV fatigue damage should be required for future investigation.

Jumper Analysis With Interacting Internal Two-Phase Flow

In 2017, the Welsh Government introduced Cymraeg 2050, an ambitious strategy to increase the number of Welsh speakers in Wales (Welsh Government, 2017). The Welsh education system is a vitally important feature of this strategy. In 2013, a review of Welsh language instruction in Key Stages 3 and 4 (Davies, 2013) identified considerable gaps in teachers’ preparation and training for teaching Welsh as a Second Language, a poor Welsh language ethos at many schools, and a general lack of resources to support the instruction of Cymraeg (or Welsh). Recommendations included several dimensions including curriculum content, pedagogical practice, and teacher assessment, training, and resources. With the advent of a new, national curricular framework (Welsh Government, 2015), this study builds on the Davies (2013) review and provides unprecedented detail into student perceptions of Welsh language instruction. Data produced through focus groups with students were analysed in consideration of Dörnyei’s group dynamics theory, providing a poignant critique of the aims for Welsh language instruction, teachers’ pedagogical practice, and what students suggest is a general disconnect between Welsh language instruction and its use in their everyday lives.

“Everything we do revolves around the exam”: What are students’ perceptions and experiences of learning Welsh as second language in Wales?

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Kevin Smith

Author Tools

Chat about Author