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\,($\overline{\nu}_e$) 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 $\overline{\nu}_e$ oscillations to sterile neutrino. Based on the comparison, we obtain a 95\% C.L. excluded region of $0.1<|\Delta m_{41}^2|<7$\,eV$^2$. We also obtain a 68\% C.L. allowed region with the best fit of $|\Delta m_{41}^2|=2.41\,\pm\,0.03\,$\,eV$^2$ and $\sin^2 2\theta_{14}$=0.08$\,\pm\,$0.03 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 sNN=2.76\sqrt{s_{\rm NN}}=2.76 TeV

The elliptic, $v_2$, triangular, $v_3$, and quadrangular, $v_4$, azimuthal anisotropic flow coefficients are measured for unidentified charged particles, pions and (anti-)protons in Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ 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 $|\eta|<0.8$ at different collision centralities and as a function of transverse momentum, $p_{\rm T}$, out to $p_{\rm T}=20$ GeV/$c$. The observed non-zero elliptic and triangular flow depends only weakly on transverse momentum for $p_{\rm T}>8$ GeV/$c$. The small $p_{\rm T}$ 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 $p_{\rm T}=8$ GeV/$c$. The magnitude of the (anti-)proton elliptic and triangular flow is larger than that of pions out to at least $p_{\rm T}=8$ GeV/$c$ indicating that the particle type dependence persists out to high $p_{\rm T}$.Comment: 16 pages, 5 captioned figures, authors from page 11, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/186