2,602 research outputs found
The Effect Of Antimony, Chloride Ion, And Glue On Copper Electrorefining
A study has been made to determine the effect of antimony, chloride ion, and glue on copper electrorefining. All deposits were made at a temperature of 65° C on a titanium cathode. Current densities of 398 A m-2 and 133 A m-2 were used. The deposits were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) to determine morphology and crystal orientation. Atomic absorption (AA) and Auger spectroscopy (AES) were used to study the chemical composition of the deposits and a simple bend test was used to determine structural integrity. It was found that when the antimony concentration in the electrolyte exceeded 300 ppm, brittle deposits were produced containing considerable amounts of antimony. Very small amounts of chloride ion (1.5 ppm or above) decreased the codeposition of antimony greatly and produced ductile deposits. However, at a chloride ion level of 15 ppm or above, the back side of the deposit had a very rough, powdery appearance. The effect of glue was to counteract this and to produce a mirror-like finish on the deposit back. © 1978 Chapman and Hall Ltd
Ethnic/racial diversity, maternal stress, lactation and very low birthweight infants.
OBJECTIVE: (1) To compare maternal characteristics and psychological stress profile among African-American, Caucasian and Hispanic mothers who delivered very low birthweight infants. (2) To investigate associations between psychosocial factors, frequency of milk expression, skin-to-skin holding (STS), and lactation performance, defined as maternal drive to express milk and milk volume. STUDY DESIGN: Self-reported psychological questionnaires were given every 2 weeks after delivery over 10 weeks. Milk expression frequency, STS, and socioeconomic variables were collected. RESULT: Infant birthweight, education, and milk expression frequency differed between groups. Trait anxiety, depression and parental stress in a neonatal intensive care unit (PSS:NICU) were similar. African-American and Caucasian mothers reported the lowest scores in state anxiety and social desirability, respectively. Maternal drive to express milk, measured by maintenance of milk expression, correlated negatively with parental role alteration (subset of PSS:NICU) and positively with infant birthweight and STS. Milk volume correlated negatively with depression and positively with milk expression frequency and STS. CONCLUSION: Differences between groups were observed for certain psychosocial factors. The response bias to self-reported questionnaires between groups may not provide an accurate profile of maternal psychosocial profile. With different factors correlating with maintenance of milk expression and milk volume, lactation performance can be best enhanced with a multi-faceted intervention program, incorporating parental involvement in infant care, close awareness and management of maternal mental health, and encouragement for frequent milk expression and STS
Microstructure identification via detrended fluctuation analysis of ultrasound signals
We describe an algorithm for simulating ultrasound propagation in random
one-dimensional media, mimicking different microstructures by choosing physical
properties such as domain sizes and mass densities from probability
distributions. By combining a detrended fluctuation analysis (DFA) of the
simulated ultrasound signals with tools from the pattern-recognition
literature, we build a Gaussian classifier which is able to associate each
ultrasound signal with its corresponding microstructure with a very high
success rate. Furthermore, we also show that DFA data can be used to train a
multilayer perceptron which estimates numerical values of physical properties
associated with distinct microstructures.Comment: Submitted to Phys. Rev.
Long-range correlation and multifractality in Bach's Inventions pitches
We show that it can be considered some of Bach pitches series as a stochastic
process with scaling behavior. Using multifractal deterend fluctuation analysis
(MF-DFA) method, frequency series of Bach pitches have been analyzed. In this
view we find same second moment exponents (after double profiling) in ranges
(1.7-1.8) in his works. Comparing MF-DFA results of original series to those
for shuffled and surrogate series we can distinguish multifractality due to
long-range correlations and a broad probability density function. Finally we
determine the scaling exponents and singularity spectrum. We conclude fat tail
has more effect in its multifractality nature than long-range correlations.Comment: 18 page, 6 figures, to appear in JSTA
Kramers escape driven by fractional Brownian motion
We investigate the Kramers escape from a potential well of a test particle
driven by fractional Gaussian noise with Hurst exponent 0<H<1. From a numerical
analysis we demonstrate the exponential distribution of escape times from the
well and analyze in detail the dependence of the mean escape time as function
of H and the particle diffusivity D. We observe different behavior for the
subdiffusive (antipersistent) and superdiffusive (persistent) domains. In
particular we find that the escape becomes increasingly faster for decreasing
values of H, consistent with previous findings on the first passage behavior.
Approximate analytical calculations are shown to support the numerically
observed dependencies.Comment: 14 pages, 16 figures, RevTeX
Long range correlation in cosmic microwave background radiation
We investigate the statistical anisotropy and Gaussianity of temperature
fluctuations of Cosmic Microwave Background radiation (CMB) data from {\it
Wilkinson Microwave Anisotropy Probe} survey, using the multifractal detrended
fluctuation analysis, rescaled range and scaled windowed variance methods. The
multifractal detrended fluctuation analysis shows that CMB fluctuations has a
long range correlation function with a multifractal behavior. By comparing the
shuffled and surrogate series of CMB data, we conclude that the multifractality
nature of temperature fluctuation of CMB is mainly due to the long-range
correlations and the map is consistent with a Gaussian distribution.Comment: 10 pages, 7 figures, V2: Added comments, references and major
correction
First Results on In-Beam gamma Spectroscopy of Neutron-Rich Na and Mg Isotopes at REX-ISOLDE
After the successful commissioning of the radioactive beam experiment at
ISOLDE (REX-ISOLDE) - an accelerator for exotic nuclei produced by ISOLDE -
first physics experiments using these beams were performed. Initial experiments
focused on the region of deformation in the vicinity of the neutron-rich Na and
Mg isotopes. Preliminary results show the high potential and physics
opportunities offered by the exotic isotope accelerator REX in conjunction with
the modern Germanium gamma spectrometer MINIBALL.Comment: 7 pages, RNB6 conference contributio
Current Practices and Considerations in Lung Biopsy for Suspected Granulomatous-Lymphocytic Interstitial Lung Disease: A Clinician Survey
Introduction: This study explores clinicians’ diagnostic practices and perceptions in the context of granulomatous-lymphocytic interstitial lung disease (GLILD), a pulmonary manifestation of common variable immunodeficiency disorder. The aim was to gain valuable insights into key aspects, such as the utilization of radiological features for diagnostic purposes, indications for lung biopsy, preferred biopsy techniques, and the relative importance of different histopathological findings in confirming GLILD. Method: A survey targeting expert clinicians was conducted, focusing on their experiences, practices, and attitudes towards lung biopsy in suspected GLILD cases. Results: The survey revealed that the majority of respondents accepted high-resolution computed tomography as a sufficient alternative to biopsy for making a probable GLILD diagnosis in most patients. There was a consensus among most respondents that the presence of extrapulmonary granulomatous disease is adequate for making a diagnosis of GLILD where the chest imaging and clinical picture are consistent. When a biopsy was recommended, there was notable variation in the preferred initial biopsy technique, with 35% favouring transbronchial biopsy. Conclusion: Our findings underscore the complexity of diagnosing GLILD, indicating varied clinician opinions on the necessity and efficacy of lung biopsies. They highlight the need for further research and the development of consistent diagnostic criteria and management protocols, ultimately aiming to enhance the accuracy and safety of GLILD diagnosis and treatment strategies
Characterization of radial turbulent fluxes in the Santander linear plasma machine
It is shown that the statistical and correlation properties of the local turbulent flux measured at different radial locations of the cold, weakly ionized plasmas inside the Santander Linear Plasma Machine [Castellanos et al., Plasma Phys. Control. Fusion 47, 2067 (2005)] are consistent with diffusive-like transport dynamics. This is in contrast to the dynamical behavior inferred from similar measurements taken in hotter, fully ionized tokamak and stellarator edge plasmas, in which longterm correlations and other features characteristic of complex, non-diffusive transport dynamics have been reported in the past. These results may shed some light on a recent controversy regarding the possible universality of the dynamics of turbulent transport in magnetized plasma
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