7,821 research outputs found
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An Evaluation of Non-Stochastic Lattice Structures Fabricated Via Electron Beam Melting
Metal foam structures have many applications and can be used as structural supports, heat
exchangers, shock absorbers, and implant materials. Stochastic metal foams having different cell
sizes and densities have been commercially available for a number of years. This paper addresses
a different type of foams which are known as non-stochastic foams, or lattice structures. These
foams have a well defined repeating unit cell structure rather than the random cell structure in
commercially available stochastic foams. The paper reports on preliminary research on the
fabrication of non-stochastic Ti-6Al-4V alloy foams using the Electron Beam Melting process.
Behavior of the structures in compression, bending, and low cycle repeating load tests are
discussed, and recommendations about cell geometry and processing conditions are made.Mechanical Engineerin
Alien Registration- Cormier, Cyr H. (Van Buren, Aroostook County)
https://digitalmaine.com/alien_docs/33142/thumbnail.jp
Two-Electron Effects in the Multiphoton Ionization of Magnesium with 400 nm 150 fs Pulses
The multiphoton ionization and photoelectron spectra of magnesium were
studied at laser intensities of up to 6x10^{13} Wcm^{-2} using 150 fs laser
pulses of a wavelength of 400 nm. The results indicated that a variety of
different ionization mechanisms played a role in both types of spectra. A
theoretical model describing the processes is presented and the routes to
ionization are identified. The work demonstrates the significance of the
two-electron nature of the atom in interpreting the experimental results.Comment: 14 pages, 9 figures, submitted to Physical Review
Interference effects in two-photon ATI by multiple orders high harmonics with random or locked phases
We numerically study 2-photon processes using a set of harmonics from a
Ti:Sapphire laser and in particular interference effects in the Above Threshold
Ionization spectra. We compare the situation where the harmonic phases are
assumed locked to the case where they have a random distribution. Suggestions
for possible experiments, using realistic parameters are discussed.Comment: 11 pages, 13 figures, LaTe
Alien Registration- Cormier, Maryrose H. (Gardiner, Kennebec County)
https://digitalmaine.com/alien_docs/29119/thumbnail.jp
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Comparison of family centered care with family integrated care and mobile technology (mFICare) on preterm infant and family outcomes: a multi-site quasi-experimental clinical trial protocol.
BackgroundFamily Centered Care (FCC) has been widely adopted as the framework for caring for infants in the Neonatal Intensive Care Unit (NICU) but it is not uniformly defined or practiced, making it difficult to determine impact. Previous studies have shown that implementing the Family Integrated Care (FICare) intervention program for preterm infants in the NICU setting leads to significant improvements in infant and family outcomes. Further research is warranted to determine feasibility, acceptability and differential impact of FICare in the US context. The addition of a mobile application (app) may be effective in providing supplemental support for parent participation in the FICare program and provide detailed data on program component uptake and outcomes.MethodsThis exploratory multi-site quasi-experimental study will compare usual FCC with mobile enhanced FICare (mFICare) on growth and clinical outcomes of preterm infants born at or before 33 weeks gestational age, as well as the stress, competence and self-efficacy of their parents. The feasibility and acceptability of using mobile technology to gather data about parent involvement in the care of preterm infants receiving FCC or mFICare as well as of the mFICare intervention will be evaluated (Aim 1). The effect sizes for infant growth (primary outcome) and for secondary infant and parent outcomes at NICU discharge and three months after discharge will be estimated (Aim 2).DiscussionThis study will provide new data about the implementation of FICare in the US context within various hospital settings and identify important barriers, facilitators and key processes that may contribute to the effectiveness of FICare. It will also offer insights to clinicians on the feasibility of a new mobile application to support parent-focused research and promote integration of parents into the NICU care team in US hospital settings.Trial registrationClinicalTrials.gov, ID NCT03418870. Retrospectively registered on December 18, 2017
On the gravitational production of superheavy dark matter
The dark matter in the universe can be in the form of a superheavy matter
species (WIMPZILLA). Several mechanisms have been proposed for the production
of WIMPZILLA particles during or immediately following the inflationary epoch.
Perhaps the most attractive mechanism is through gravitational particle
production, where particles are produced simply as a result of the expansion of
the universe. In this paper we present a detailed numerical calculation of
WIMPZILLA gravitational production in hybrid-inflation models and
natural-inflation models. Generalizing these findings, we also explore the
dependence of the gravitational production mechanism on various models of
inflation. We show that superheavy dark matter production seems to be robust,
with Omega_X h^2 ~ (M_X / (10^11 GeV))^2 (T_RH / (10^9 GeV)), so long as M_X <
H_I, where M_X is the WIMPZILLA mass, T_RH is the reheat temperature, and H_I
is the expansion rate of the universe during inflation.Comment: 26 pages, 7 figures; LaTeX; submitted to Physical Review D; minor
typographical error correcte
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Design and Characterization of Orthotropic Re-Entrant Auxetic Structures Made via EBM Using Ti6Al4V and Pure Copper
An orthotropic 3D re-entrant honeycomb structure that exhibits a negative Poisson’s ratio
was designed and fabricated via the electron beam melting (EBM) process. The modeling work
established the relationships between various structural parameters and the mechanical properties
of the auxetic structures. Compressive tests were performed on the re-entrant honeycomb
samples made with Ti6Al4V as well as pure copper. Results of the strength, modulus and energy
absorption for the two materials were compared with the theoretical models in order to verify the
theoretical predictions.Mechanical Engineerin
Évaluation des besoins et de l’utilisation de services de santé mentale dans la schizophrénie*
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