705 research outputs found
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Al2O3 Precursor Evaluation for SALD Joining
SFF technology is not limited to the creation of components and objects. Freeform
technology can be a mechanism for joining of materials. By defining the space between two
objects as the boundary for a free-form object it is possible to form a three dimensional joint fill.
Selective Area Laser Deposition or SALD, has been used for free form and joining of carbides
and nitrides but has the potential to make other classes of ceramics. By selecting a metal-organic
precursor and an oxidizer, an oxide can be created by CVD gas decomposition. In this study such
oxide joint fill precursors are studied, particularly for alumina.Mechanical Engineerin
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Ceramic Joining by Gas Phase Pulsed Laser Processing
The method of Selective Area Laser Deposition (SALD) and Vapor Infiltration
(SALDVI) has been successfully used to fabricate small three-dimensional SiC/SiC and
SiC/metal powder parts. Ceramic joints made by this technique have been limited by the
throwing power of the laser resulting in incomplete joint penetration. Studies were performed to
show the effectiveness of a fiber laser, with a wavelength of 1070 nm, for a joining process. The
ability of the laser to penetrate a powder bed was utilized in the joint fabrication. The
combination of powder fill, and deep laser penetration into the powder bed shows potential in the
field of ceramic joining.Mechanical Engineerin
New Photodetection Method Using Unbalanced Sidebands for Squeezed Quantum Noise in Gravitational Wave Interferometer
Homodyne detection is one of the ways to circumvent the standard quantum
limit for a gravitational wave detector. In this paper it will be shown that
the same quantum-non-demolition effect using homodyne detection can be realized
by heterodyne detection with unbalanced RF sidebands. Furthermore, a broadband
quantum-non-demolition readout scheme can also be realized by the unbalanced
sideband detection.Comment: 9 pages, 5 figure
Intrathekale Opioidmedikation zur perioperativen Analgesie bei schwer behinderten Kindern mit Wirbelsäulenoperationen
Zusammenfassung: Hintergrund: An gesunden Kindern konnte gezeigt werden, dass intrathekal verabreichte Opioide eine sichere und effektive perioperative Analgesie bei wirbelsäulenchirurgischen Eingriffen ermöglichen. Das Ziel der vorliegenden Untersuchung ist es, ihre Anwendbarkeit bei schwer- und schwerstbehinderten Kindern für wirbelsäulenchirurgische Eingriffe zu überprüfen. Methode: Mit Zustimmung der lokalen Ethikkommission wurden Patienten vom Status3 und 4 der Klassifikation der American Society of Anesthesiologists (ASA), die sich einem wirbelsäulenchirurgischen Eingriff unterziehen mussten, retrospektiv untersucht. Zusätzlich zur Allgemeinanästhesie mit Sevofluran oder i.v.-verabreichtem Propofol erhielten die Patienten vor der Operation 20µg/kgKG Morphin und 1,5µg/kgKG Sufentanil intrathekal. Nach Beendigung des Eingriffs wurde eine Nalbuphindauerinfusion gestartet. Der Bedarf an zusätzlichen intra- und postoperativen Analgetika, der Zeitpunkt der Extubation, die postoperativen Schmerz-Scores und die arteriellen Kohlendioxidpartialdruck- (paCO2)-Werte sowie das Auftreten unerwünschter Nebenwirkungen wurden untersucht. Ergebnisse: Es wurden 28Patienten im Alter von 2,8 bis 18,5Jahren (Median 11,6Jahre) untersucht. Unmittelbar im OP konnten 17Patienten extubiert werden; bei 11Patienten entschied man sich zu einer verzögerten Extubation. Bis auf einen Patienten mit postoperativer Massivtransfusion konnten alle innerhalb von 24h extubiert werden. Eine adäquate postoperative Analgesie mit Schmerz-Scores ≤3 wurde mithilfe der Kombination von intrathekal verabreichten Opioiden mit Nalbuphin postoperativ bei 26 von 28Patienten (93%) erreicht. Bei 2Patienten war der Wechsel auf eine i.v.-Morphin-Gabe erforderlich. Postoperative Übelkeit und Erbrechen ("postoperative nausea and vomiting", PONV), Pruritus und leichte Hypoventilation mit paCO2-Werten zwischen 5,2 bis 9,7kPa (Median 6,3kPa) waren die beobachteten Nebenwirkungen. Schlussfolgerung: Der Einsatz intrathekal verabreichter Opioide, ergänzt durch eine postoperative Nalbuphininfusion, erlaubt in den allermeisten Fällen eine frühzeitige Extubation ohne persistierende Atemdepression und ist eine praktikable sowie effektive Methode zur postoperativen Analgesie bei schwer behinderten Kindern nach wirbelsäulenchirurgischen Eingriffe
Weak-Localization in Chaotic Versus Non-Chaotic Cavities: A Striking Difference in the Line Shape
We report experimental evidence that chaotic and non-chaotic scattering
through ballistic cavities display distinct signatures in quantum transport. In
the case of non-chaotic cavities, we observe a linear decrease in the average
resistance with magnetic field which contrasts markedly with a Lorentzian
behavior for a chaotic cavity. This difference in line-shape of the
weak-localization peak is related to the differing distribution of areas
enclosed by electron trajectories. In addition, periodic oscillations are
observed which are probably associated with the Aharonov-Bohm effect through a
periodic orbit within the cavities.Comment: 4 pages revtex + 4 figures on request; amc.hub.94.
A constructive approach to the soliton solutions of integrable quadrilateral lattice equations
Scalar multidimensionally consistent quadrilateral lattice equations are
studied. We explore a confluence between the superposition principle for
solutions related by the Backlund transformation, and the method of solving a
Riccati map by exploiting two kn own particular solutions. This leads to an
expression for the N-soliton-type solutions of a generic equation within this
class. As a particular instance we give an explicit N-soliton solution for the
primary model, which is Adler's lattice equation (or Q4).Comment: 22 page
CARACTERÍSTICAS DO SÊMEN DO CÃO APÓS DILUIÇÃO E RESFRIAMENTO
O objetivo do presente trabalho foi de avaliar a eficiência de quatro diferentes diluentes
na conservação do sêmen canino, no decorrer de 96 horas de armazenamento a 5oC. Para o
experimento foram selecionados dois cães sem raça definida, de mesma idade e porte. Foram
colhidos cinco ejaculados de cada cão durante cinco semanas, sendo que os ejaculados foram
diluídos respectivamente em TRIS-gema (A), leite desnatado reidratado(B), TRIS-gema + secreção
prostática (C) e leite desnatado reidratado + secreção prostática(D). As amostras foram avaliadas
antes da diluição e na hora 0 (imediatamente após a diluição), 24, 48, 72 e 96 horas pós-resfriamento
a 5oC, assim como as amostras de sêmen não diluído foram avaliadas da mesma forma, para
efeitos comparativos. A avaliação do sêmen deu-se através da motilidade progressiva e da integridade
de acrossoma. A motilidade espermática mínima de 50,0 %, permaneceu em 53,5% até 72 horas
para a diluição do sêmen canino em diluente A; em 59,5 % até 48 horas para o diluente B; em 61,5
% até 48 horas para o diluente C e em 57,5 % até 24 horas para o diluente D. Por sua vez as células
espermáticas mantiveram a integridade de acrossomo em 66,5%, 65,4%, 74,2% e 64,7% até 96
horas pós-diluição e resfriamento para os diluentes A, B,C e D, respectivamente. Pôde-se concluir
que o diluente TRIS-gema mostrou-se superior aos demais, porque manteve a motilidade espermática
por mais tempo. O sêmen não diluído foi incapaz de manter a motilidade progressiva dentro das 24
horas, embora tenha mantido a integridade de acrossomo até 72 horas após sua obtenção.
Canine semen characteristics after dilution and cooling
Abstract
The aim of the current study was to evaluate the efficiency of four different diluents for
canine semen preservation during 96 hours of storage at 5 oC. Two mixed-breed dogs of about the
same age and size were used for this study. Five ejaculates were collected from each dog within five
weeks, and the ejaculates were divided in TRIS-yolk (A), re-hydrated milk without cream (B), TRISyolk
+ prostatic secretion (C) and re-hydrated milk without cream + prostatic secretion (D). The samples
were evaluated before dilution was performed and at times 0 (immediately after dilution), 24, 48, 72
and 96 hours after-cooling at 5 oC, as well as the non-diluted semen samples (for comparative
purposes). The semen evaluation was performed accessing progressive motility and the acrossomal
integrity. The minimal spermatic motility was of 50.0 % and remained in 53.5% until 72 hours for
diluent A; 59.5% until 48 hours for diluent B, 61.5% until 48 hours for diluent C and 57.5% until 24
hours for diluent D. The spermatic cells sustained the acrossomal integrity in 66.5%, 65.4%, 74.2%
and 64.7% until 96 hours after dilution and cooling for diluents A, B, C and D, respectively. In conclusion,
the TRIS-yolk diluent was superior because it sustained the spermatic motility for a longer period.
The non-diluted semen was unable to maintain the progressive motility within the 24 hours, although
it kept the acrossomal integrity until 72 hours after being collected
Corrections to the Central Limit Theorem for Heavy-Tailed Probability Densities
Classical Edgeworth expansions provide asymptotic correction terms to the
Central Limit Theorem (CLT) up to an order that depends on the number of
moments available. In this paper, we provide subsequent correction terms beyond
those given by a standard Edgeworth expansion in the general case of regularly
varying distributions with diverging moments (beyond the second). The
subsequent terms can be expressed in a simple closed form in terms of certain
special functions (Dawson's integral and parabolic cylinder functions), and
there are qualitative differences depending on whether the number of moments
available is even, odd or not an integer, and whether the distributions are
symmetric or not. If the increments have an even number of moments, then
additional logarithmic corrections must also be incorporated in the expansion
parameter. An interesting feature of our correction terms for the CLT is that
they become dominant outside the central region and blend naturally with known
large-deviation asymptotics when these are applied formally to the spatial
scales of the CLT
Didactic Software for Autistic Children
In this paper we describe the aims and requirements of a project devoted to designing and developing Open Source didactic Software (SW) for children in the autism disorder spectrum, conforming to the Applied Behaviour Analysis (ABA) learning technique. In this context, participatory design with therapists and child?s parents is necessary to ensure a usable product that responds to these children?s special needs and respects education principles and constraints of the ABA methodology
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