1,583 research outputs found
Energy coupling to ATP synthesis and pyridine nucleotide transhydrogenase in chromatophores from photosynthetic bacteria A ‘dual-consumer’ test for localised interactions with electron transport components
AbstractThe rate of ATP synthesis and the rate of pyridine nucleotide transhydrogenase were recorded in parallel experiments in steady-state conditions following the onset of illumination in chromatophores of Rhodobacter capsulatus (formerly Rhodopseudomonas capsulata). The transhydrogenase rate was more resistant than the ATP synthesis rate to inhibition by antimycin A and myxothiazol, the uncoupler, carbonyl cyanide p-trifluoromethoxyphenylhydrazone and the combination of valinomycin with nigericin in the presence of K+. The relationship between the transhydrogenase rate and the ATP synthesis rate was not influenced by the nature of the inhibitor. These data suggest that the ATP synthase and the transhydrogenase are differentially regulated by Δp but not by local interactions with components of the electron transport chain
Pitch-scaled estimation of simultaneous voiced and turbulence-noise components in speech
Almost all speech contains simultaneous contributions from more than one acoustic source within the speaker's vocal tract. In this paper, we propose a method -- the pitch-scaled harmonic filter (PSHF) -- which aims to separate the voiced and turbulence-noise components of the speech signal during phonation, based on a maximum-likelihood approach. The PSHF outputs periodic and aperiodic components that are estimates of the respective contributions of the different types of acoustic source. It produces four reconstructed time series signals by decomposing the original speech signal, first, according to amplitude, and then according to power of the Fourier coefficients. Thus, one pair of periodic and aperiodic signals is optimized for subsequent time-series analysis, and another pair for spectral analysis. The performance of the PSHF algorithm was tested on synthetic signals, using three forms of disturbance (jitter, shimmer and additive noise), and the results were used to predict the performance on real speech. Processing recorded speech examples elicited latent features from the signals, demonstrating the PSHF's potential for analysis of mixed-source speech
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A Review of Hybrid Manufacturing
In recent years the combination of laser-based Additive Manufacturing and Computer
Numerical Controlled (CNC) machining has become increasingly popular, with several machine
tool manufacturers exhibiting products based on different machine tool configurations. This
technology, widely known as Hybrid Manufacturing, generally exploits Directed Energy
Deposition processes using powder feedstock that is fed into a melt pool created by a laser.
Although Directed Energy Deposition processes predate powder bed fusion Additive
Manufacturing (at least in terms of coating and repair applications), commercialization of Hybrid
Manufacturing systems is still very much in its infancy. However, they do offer clear advantages,
combining a high deposition rate together with the accuracy and surface finish associated with
machining. This paper presents the history of the development of Hybrid Manufacturing Systems
(HMS), dating back from work undertaken in the mid 1990s through to the present day. The
relative merits of different material deposition approaches are compared and some of the key
technical challenges which remain are highlighted and discussed.Mechanical Engineerin
The QCD Phase Diagram at Nonzero Temperature, Baryon and Isospin Chemical Potentials in Random Matrix Theory
We introduce a random matrix model with the symmetries of QCD at finite
temperature and chemical potentials for baryon number and isospin. We analyze
the phase diagram of this model in the chemical potential plane for different
temperatures and quark masses. We find a rich phase structure with five
different phases separated by both first and second order lines. The phases are
characterized by the pion condensate and the chiral condensate for each of the
flavors. In agreement with lattice simulations, we find that in the phase with
zero pion condensate the critical temperature depends in the same way on the
baryon number chemical potential and on the isospin chemical potential. At
nonzero quark mass, we remarkably find that the critical end point at nonzero
temperature and baryon chemical potential is split in two by an arbitrarily
small isospin chemical potential. As a consequence, there are two crossovers
that separate the hadronic phase from the quark-gluon plasma phase at high
temperature. Detailed analytical results are obtained at zero temperature and
in the chiral limit.Comment: 13 pages, 5 figures, REVTeX
Finite temperature mobility of a particle coupled to a fermion environment
We study numerically the finite temperature and frequency mobility of a
particle coupled by a local interaction to a system of spinless fermions in one
dimension. We find that when the model is integrable (particle mass equal to
the mass of fermions) the static mobility diverges. Further, an enhanced
mobility is observed over a finite parameter range away from the integrable
point. We present a novel analysis of the finite temperature static mobility
based on a random matrix theory description of the many-body Hamiltonian.Comment: 11 pages (RevTeX), 5 Postscript files, compressed using uufile
Cloud based machine learning approaches for leakage assessment and management in smart water networks
One-third of utilities around the globe report a loss of more than 40 percent of clean water due to leaks. By reducing the amount of water leaked, smart water networks can help reduce the money wasted on producing or purchasing water, and the related energy required to pump water and treat water for distribution. A UK demo site is presented focusing on leak management, integrating fixed flow and pressure instrumentation, advanced (smart) metering infrastructure and novel instruments (capable of high resolution monitoring). Example data analysis results for this site using the AURA-Alert anomaly detection system for Condition Monitoring are presented
Second Harmonic Generation for a Dilute Suspension of Coated Particles
We derive an expression for the effective second-harmonic coefficient of a
dilute suspension of coated spherical particles. It is assumed that the coating
material, but not the core or the host, has a nonlinear susceptibility for
second-harmonic generation (SHG). The resulting compact expression shows the
various factors affecting the effective SHG coefficient. The effective SHG per
unit volume of nonlinear coating material is found to be greatly enhanced at
certain frequencies, corresponding to the surface plasmon resonance of the
coated particles. Similar expression is also derived for a dilute suspension of
coated discs. For coating materials with third-harmonic (THG) coefficient,
results for the effective THG coefficients are given for the cases of coated
particles and coated discs.Comment: 11 pages, 3 figures; accepted for publication in Phys. Rev.
Integration of epitaxial colossal magnetoresistive films onto Si(100) using SrTiO\u3csub\u3e3\u3c/sub\u3e as a template layer
We report on the integration of epitaxial colossal magnetoresistive La0.67Ba0.33MnO films on Si(100) semiconductor using SrTiO3 template layer by pulsed-laser deposition. X-ray diffraction reveals the superior quality of the manganite film that grows epitaxially on heteroepitaxially grown SrTiO3 template layer on Si substrate. The epitaxial films demonstrate remarkable surface morphology, magnetic transition and hysteresis, magnetoresistance, and ferromagnetic resonance, illustrating the ferromagnetic nature of the film and possible device applications at room temperature
Towards a quantitative phase-field model of two-phase solidification
We construct a diffuse-interface model of two-phase solidification that
quantitatively reproduces the classic free boundary problem on solid-liquid
interfaces in the thin-interface limit. Convergence tests and comparisons with
boundary integral simulations of eutectic growth show good accuracy for
steady-state lamellae, but the results for limit cycles depend on the interface
thickness through the trijunction behavior. This raises the fundamental issue
of diffuse multiple-junction dynamics.Comment: 4 pages, 2 figures. Better final discussion. 1 reference adde
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