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Flammability and Thermal Properties of Polyamide 11-Alumina Nanocomposites
Neat polyamides 11 and 12 lack high strength/high heat resistance and flame retardancy.
The incorporation of selected nanoparticles is expected to enhance these properties to a
level that is desired and required for performance driven applications. This enhancement
may result in additional market opportunities for the polyamide 11 and 12 polymer
manufacturers. The objective of this study is to develop polyamide 11 polymer
nanocomposites with enhanced thermal, flammability, and mechanical performance for
selective laser sintering (SLS) rapid manufacturing. Three types of nano-alumnia (X-0
needle, X-25SR, and X-0SR) with different organic treatments were melt-compounded
into polyamide 11 in three different weight loadings of the nanoparticles (2.5%, 5%, and
7.5%). Injection molded specimens were fabricated for thermal, flammability, and
mechanical properties characterization. Although nano-alumina was uniformly dispersed
in polyamide 11 and better thermal stability of the nanomodified materials was observed,
the desired FR characteristics of the nanomodified polyamide 11 was not achieved. None
of the materials passed the desired UL 94 V0 rating.Mechanical Engineerin
Gallbladder agenesis mimicking cholelithiasis in an adult
We present the case of a 24-year-old woman with morbid obesity who came to the emergency department with right upper quadrant abdominal pain associated with nausea and vomiting. Her workup included a right upper quadrant ultrasound suggestive of a small gallbladder with cholelithiasis without sonographic evidence of acute cholecystitis. She underwent attempted laparoscopic cholecystectomy with no identifiable gallbladder during surgery. Postsurgical cross-sectional imaging confirmed gallbladder agenesis. This case provides an example of a rare but convincing clinical and radiologic mimic of cholelithiasis. In certain cases of biliary colic and imaging revealing a small gallbladder, a magnetic resonance cholangiopancreatography may be warranted to evaluate gallbladder agenesis and avoid unnecessary surgery
Benefits of active middle ear implants over hearing aids in patients with sloping high tone hearing loss: comparison with hearing aids
In questo studio retrospettivo, abbiamo confrontato i benefici oggettivi e soggettivi degli impianti attivi dell’orecchio medio (AMEI) rispetto alle tradizionali protesi acustiche (HA) nei pazienti con perdita dell’udito per le frequenze acute. Trentaquattro pazienti con ipoacusia neurosensoriale sono stati trattati con l’impianto di AMEI. Tra questi, sei avevano un audiogramma “in discesa” con perdita dell’udito per le frequenze acute, ed avevano usato per più di sei mesi HA. È stata quindi eseguita una valutazione oggettiva, tramite l’audiometria tonale e il test di riconoscimento delle parole, una versione coreana del “Hearing in Noise Test” (K-HINT), ed una valutazione soggettiva tramite il seguente questionario: Abbreviated Profile of Hearing Aid Benefit (APHAB). I pazienti sono stati sottoposti ai suddetti test in tre occasioni distinte: 1) prima della chirurgia, senza protesi; 2) prima della chirurgia, con HA; 3) tre mesi dopo l’impianto di AMEI. Il guadagno medio per le alte frequenze (≥ 2 kHz) si è rivelato migliore con AMEI che con HA. Sebbene il risultato non ha raggiunto un livello di significatività statistica, gli impianti attivi dell’orecchio medio hanno mostrato un punteggio di riconoscimento delle parole superiore rispetto a HA. Ad ogni modo, il livello di comoda udibilità al quale il punteggio di riconoscimento delle parole è stato testato si è rivelato significativamente più basso con AMEI rispetto ad HA. Al K-HINT i pazienti con AMEI hanno mostrato un migliore riconoscimento rispetto ai risultati ottenuti con HA, sia in condizione di quiete sia di rumore. Gli score APAHB hanno rivelato che i pazienti erano più soddisfatti con AMEI. L’uso degli impianti attivi dell’orecchio medio in pazienti con perdita dell’udito per le frequenze acute ha permesso di ottenere risultati migliori rispetto all’utilizzo delle protesi tradizionali. Basandoci su questi dati, gli AMEI hanno offerto risultati oggettivi e soggettivi migliori, e pertanto, potrebbero rappresentare una valida alternativa per il trattamento delle ipoacusie con audiogramma in discesa
Ultra-high modulation depth exceeding 2,400% in the optically-controlled topological surface plasmons
Modulating light via coherent charge oscillations in solids is the subject of intense research topics in opto-plasmonics. Although a variety of methods are proposed to increase such modulation efficiency, one central challenge is to achieve a high modulation depth ( defined by a ratio of extinction with/without light) under small photon-flux injection, which becomes a fundamental trade-off issue both in metals and semiconductors. Here, by fabricating simple micro-ribbon arrays of topological insulator Bi2Se3, we report an unprecedentedly large modulation depth of 2,400% at 1.5 THz with very low optical fluence of 45 mu J cm(-2). This was possible, first because the extinction spectrum is nearly zero due to the Fano-like plasmon-phonon-destructive interference, thereby contributing an extremely small denominator to the extinction ratio. Second, the numerator of the extinction ratio is markedly increased due to the photoinduced formation of massive two-dimensional electron gas below the topological surface states, which is another contributor to the ultra-high modulation depth.112115Ysciescopu
Hamiltonian theory of gaps, masses and polarization in quantum Hall states: full disclosure
I furnish details of the hamiltonian theory of the FQHE developed with Murthy
for the infrared, which I subsequently extended to all distances and apply it
to Jain fractions \nu = p/(2ps + 1). The explicit operator description in terms
of the CF allows one to answer quantitative and qualitative issues, some of
which cannot even be posed otherwise. I compute activation gaps for several
potentials, exhibit their particle hole symmetry, the profiles of charge
density in states with a quasiparticles or hole, (all in closed form) and
compare to results from trial wavefunctions and exact diagonalization. The
Hartree-Fock approximation is used since much of the nonperturbative physics is
built in at tree level. I compare the gaps to experiment and comment on the
rough equality of normalized masses near half and quarter filling. I compute
the critical fields at which the Hall system will jump from one quantized value
of polarization to another, and the polarization and relaxation rates for half
filling as a function of temperature and propose a Korringa like law. After
providing some plausibility arguments, I explore the possibility of describing
several magnetic phenomena in dirty systems with an effective potential, by
extracting a free parameter describing the potential from one data point and
then using it to predict all the others from that sample. This works to the
accuracy typical of this theory (10 -20 percent). I explain why the CF behaves
like free particle in some magnetic experiments when it is not, what exactly
the CF is made of, what one means by its dipole moment, and how the comparison
of theory to experiment must be modified to fit the peculiarities of the
quantized Hall problem
Understanding COVID-19-associated coagulopathy
COVID-19-associated coagulopathy (CAC) is a life-threatening complication of SARS-CoV-2 infection. However, the underlying cellular and molecular mechanisms driving this condition are unclear. Evidence supports the concept that CAC involves complex interactions between the innate immune response, the coagulation and fibrinolytic pathways, and the vascular endothelium, resulting in a procoagulant condition. Understanding of the pathogenesis of this condition at the genomic, molecular and cellular levels is needed in order to mitigate thrombosis formation in at-risk patients. In this Perspective, we categorize our current understanding of CAC into three main pathological mechanisms: first, vascular endothelial cell dysfunction; second, a hyper-inflammatory immune response; and last, hypercoagulability. Furthermore, we pose key questions and identify research gaps that need to be addressed to better understand CAC, facilitate improved diagnostics and aid in therapeutic development. Finally, we consider the suitability of different animal models to study CAC
Modeling the Subsurface Structure of Sunspots
While sunspots are easily observed at the solar surface, determining their
subsurface structure is not trivial. There are two main hypotheses for the
subsurface structure of sunspots: the monolithic model and the cluster model.
Local helioseismology is the only means by which we can investigate
subphotospheric structure. However, as current linear inversion techniques do
not yet allow helioseismology to probe the internal structure with sufficient
confidence to distinguish between the monolith and cluster models, the
development of physically realistic sunspot models are a priority for
helioseismologists. This is because they are not only important indicators of
the variety of physical effects that may influence helioseismic inferences in
active regions, but they also enable detailed assessments of the validity of
helioseismic interpretations through numerical forward modeling. In this paper,
we provide a critical review of the existing sunspot models and an overview of
numerical methods employed to model wave propagation through model sunspots. We
then carry out an helioseismic analysis of the sunspot in Active Region 9787
and address the serious inconsistencies uncovered by
\citeauthor{gizonetal2009}~(\citeyear{gizonetal2009,gizonetal2009a}). We find
that this sunspot is most probably associated with a shallow, positive
wave-speed perturbation (unlike the traditional two-layer model) and that
travel-time measurements are consistent with a horizontal outflow in the
surrounding moat.Comment: 73 pages, 19 figures, accepted by Solar Physic
Search for sterile neutrino oscillation using RENO and NEOS data
We present a reactor model independent search for sterile neutrino
oscillation using 2\,509\,days of RENO near detector data and 180 days of NEOS
data. The reactor related systematic uncertainties are significantly suppressed
as both detectors are located at the same reactor complex of Hanbit Nuclear
Power Plant. The search is performed by electron
antineutrino\,() disappearance between six reactors and two
detectors with baselines of 294\,m\,(RENO) and 24\,m\,(NEOS). A spectral
comparison of the NEOS prompt-energy spectrum with a no-oscillation prediction
from the RENO measurement can explore reactor oscillations
to sterile neutrino. Based on the comparison, we obtain a 95\% C.L. excluded
region of \,eV. We also obtain a 68\% C.L. allowed
region with the best fit of \,eV and
=0.080.03 with a p-value of 8.2\%. Comparisons of
obtained reactor antineutrino spectra at reactor sources are made among RENO,
NEOS, and Daya Bay to find a possible spectral variation.Comment: 6 pages, 5 figures: This manuscript has been significantly revised by
the joint reanalysis by RENO and NEOS Collaborations. (In the previous
edition, the RENO collaboration used publicly available NEOS data to evaluate
the expected neutrino spectrum at NEOS.
Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at TeV
The elliptic, , triangular, , and quadrangular, , azimuthal
anisotropic flow coefficients are measured for unidentified charged particles,
pions and (anti-)protons in Pb-Pb collisions at TeV
with the ALICE detector at the Large Hadron Collider. Results obtained with the
event plane and four-particle cumulant methods are reported for the
pseudo-rapidity range at different collision centralities and as a
function of transverse momentum, , out to GeV/.
The observed non-zero elliptic and triangular flow depends only weakly on
transverse momentum for GeV/. The small dependence
of the difference between elliptic flow results obtained from the event plane
and four-particle cumulant methods suggests a common origin of flow
fluctuations up to GeV/. The magnitude of the (anti-)proton
elliptic and triangular flow is larger than that of pions out to at least
GeV/ indicating that the particle type dependence persists out
to high .Comment: 16 pages, 5 captioned figures, authors from page 11, published
version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/186
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