13,493 research outputs found
Polymeric templating synthesis of anatase TiO₂ nanoparticles from low-cost inorganic titanium sources
A novel facile and cost-effective synthesis method for anatase TiO₂ nanoparticles has been developed by using poly-acrylic acid hydrogel as template at room temperature. The newly developed synthesis method avoids the use of hazardous reagents and/or hydrothermal steps, and enables production of highly active TiO₂ nanoparticles from low cost inorganic titanium sources. The synthesized TiO₂ nanoparticles have been studied in several applications including dye-sensitized solar cells as a photoanode as well as in organics degradation of methyl orange in aqueous media. Good photocatalytic performances were obtained in both applications
A study of cavitation induced surface erosion in abrasive waterjet cutting systems
Current jet cutting systems experience severe nozzle erosion and associated maintenance and downtime costs. An experimental investigation was conducted to qualitatively and quantitatively analyse the generation of cavitation in a high pressure water jet cutting system, and to characterise cavitation induced accelerated surface erosion by slurries. The analysis of surface morphology indicates that the shearing induced by cavitation played a major role in the erosion process. The results promise a feasible solution to reduce nozzle wear, and to enhance material removal in the jet cutting process
The effect of gamma irradiation on the biological properties of intervertebral disc allografts: in vitro and in vivo studies in a beagle model
published_or_final_versio
Recommended from our members
A Reliable Method for Recycling (RE)-Ba-Cu-O (RE: Sm, Gd, Y) Bulk Superconductors
Single grain (RE)-Ba-Cu-O (RE: Sm, Gd, Y) high temperature superconductors are able to generate high magnetic fields. However, the relatively high cost of the raw materials and the low yield of the manufacturing process have impeded the development of practical applications of these materials to date. This article describes a simple, reliable and economical method of recycling failed bulk (RE)-Ba-Cu-O (RE: Sm, Gd, Y) samples. Sixty-four failed bulk samples, with diameters up to 31 mm, were recycled with a yield of 90%. The key innovation in this recycling process involves reintroducing the liquid phase into the melt process, which is normally lost during the primary peritectic processing of these materials. This enables the direct re-growth of failed samples from solid form without the need for re-grinding into powder. We also demonstrate that the superconducting performance and microstructure of the recycled samples is similar to that of the primary grown samples.We acknowledge the Engineering and Physical Sciences Research Council (EPSRC grant ref.EP/K02910X/1) for financial support.This is the final version. It first appeared at http://dx.doi.org/10.1111/jace.1368
Hot Streaks in Artistic, Cultural, and Scientific Careers
The hot streak, loosely defined as winning begets more winnings, highlights a
specific period during which an individual's performance is substantially
higher than her typical performance. While widely debated in sports, gambling,
and financial markets over the past several decades, little is known if hot
streaks apply to individual careers. Here, building on rich literature on
lifecycle of creativity, we collected large-scale career histories of
individual artists, movie directors and scientists, tracing the artworks,
movies, and scientific publications they produced. We find that, across all
three domains, hit works within a career show a high degree of temporal
regularity, each career being characterized by bursts of high-impact works
occurring in sequence. We demonstrate that these observations can be explained
by a simple hot-streak model we developed, allowing us to probe quantitatively
the hot streak phenomenon governing individual careers, which we find to be
remarkably universal across diverse domains we analyzed: The hot streaks are
ubiquitous yet unique across different careers. While the vast majority of
individuals have at least one hot streak, hot streaks are most likely to occur
only once. The hot streak emerges randomly within an individual's sequence of
works, is temporally localized, and is unassociated with any detectable change
in productivity. We show that, since works produced during hot streaks garner
significantly more impact, the uncovered hot streaks fundamentally drives the
collective impact of an individual, ignoring which leads us to systematically
over- or under-estimate the future impact of a career. These results not only
deepen our quantitative understanding of patterns governing individual
ingenuity and success, they may also have implications for decisions and
policies involving predicting and nurturing individuals with lasting impact
Preparation and characterization of adherent autocatalytically deposited nickel coating on carbon fiber
In the present study carbon fibers were successfully coated with nanocrystalline nickel using an acidic bath by electroless plating method. Coating thickness obtained was about 1.5 microns beyond that there was coating delamination. Coated fibers were characterized for various properties such as morphology, composition, structure, phase transformation temperature, resistivity and tensile strength. Field emission scanning electron microscope (FESEM) studies revealed that the coating showed nodular morphology. Energy dispersive analysis of X-ray (EDAX) showed that the coating containing about 10.5 wt.% P with balance Ni. Structural studies carried out on these coated fibers exhibited two major diffraction peaks and were assigned as C (002) and Ni (111). Differential scanning calorimetry (DSC) studies on these coated fibers exhibited a single exothermic peak at 3510C. Activation energy obtained for the crystallization process of high P deposit is about 215.9 kJ/mol. Bulk resistivity was measured using four-probe technique over a single coated fiber and the obtained value was around 3.2 μΩ-m. Tensile strength of these coated fibers were also carried out and observed that not much variation found in the strength of coated and uncoated fibers
Visualizing the microscopic coexistence of spin density wave and superconductivity in underdoped NaFe1-xCoxAs
Although the origin of high temperature superconductivity in the iron
pnictides is still under debate, it is widely believed that magnetic
interactions or fluctuations play an important role in triggering Cooper
pairing. Because of the relevance of magnetism to pairing, the question of
whether long range spin magnetic order can coexist with superconductivity
microscopically has attracted strong interests. The available experimental
methods used to answer this question are either bulk probes or local ones
without control of probing position, thus the answers range from mutual
exclusion to homogeneous coexistence. To definitively answer this question,
here we use scanning tunneling microscopy to investigate the local electronic
structure of an underdoped NaFe1-xCoxAs near the spin density wave (SDW) and
superconducting (SC) phase boundary. Spatially resolved spectroscopy directly
reveal both the SDW and SC gap features at the same atomic location, providing
compelling evidence for the microscopic coexistence of the two phases. The
strengths of the SDW and SC features are shown to anti correlate with each
other, indicating the competition of the two orders. The microscopic
coexistence clearly indicates that Cooper pairing occurs when portions of the
Fermi surface (FS) are already gapped by the SDW order. The regime TC < T <
TSDW thus show a strong resemblance to the pseudogap phase of the cuprates
where growing experimental evidences suggest a FS reconstruction due to certain
density wave order. In this phase of the pnictides, the residual FS has a
favorable topology for magnetically mediated pairing when the ordering moment
of the SDW is small.Comment: 18 pages, 4 figure
Primer for intensive care unit (ICU) redeployment of the noncritical care surgeon: Insights from the epicenter of the coronavirus disease 2019 (COVID-19) pandemic
Mixed Matrix Carbon Molecular Sieve and Alumina (CMS-Al₂O₃) Membranes
This work shows mixed matrix inorganic membranes prepared by the vacuum-assisted impregnation method, where phenolic resin precursors filled the pore of a-alumina substrates. Upon carbonisation, the phenolic resin decomposed into several fragments derived from the backbone of the resin matrix. The final stages of decomposition (>650 degrees C) led to a formation of carbon molecular sieve (CMS) structures, reaching the lowest average pore sizes of similar to 5 angstrom at carbonisation temperatures of 700 degrees C. The combination of vacuum-assisted impregnation and carbonisation led to the formation of mixed matrix of CMS and a-alumina particles (CMS-Al2O3) in a single membrane. These membranes were tested for pervaporative desalination and gave very high water fluxes of up to 25 kg m(-2) h(-1) for seawater (NaCl 3.5 wt%) at 75 degrees C. Salt rejection was also very high varying between 93-99% depending on temperature and feed salt concentration. Interestingly, the water fluxes remained almost constant and were not affected as feed salt concentration increased from 0.3, 1 and 3.5 wt%
- …