Hole Fraction Dependence on Linear Viscosity of PS, PP and ABS

2015 ◽  
Vol 30 (5) ◽  
pp. 585-592 ◽  
Author(s):  
F. Sahin-Dinc
Keyword(s):  
Hole Fraction

scholarly journals On the Estimation of Confidence Intervals for Binomial Population Proportions in Astronomy: The Simplicity and Superiority of the Bayesian Approach

2011 ◽  
Vol 28 (2) ◽  
pp. 128-139 ◽  
Author(s):  
Ewan Cameron
Keyword(s):  
Confidence Intervals ◽  
Normal Approximation ◽  
Astronomical Surveys ◽  
Software Packages ◽  
Under Sampling ◽  
Astronomical Research ◽  
Binomial Statistics ◽  
Quantities Of Interest ◽  
Fraction Active ◽  
Hole Fraction

AbstractI present a critical review of techniques for estimating confidence intervals on binomial population proportions inferred from success counts in small to intermediate samples. Population proportions arise frequently as quantities of interest in astronomical research; for instance, in studies aiming to constrain the bar fraction, active galactic nucleus fraction, supermassive black hole fraction, merger fraction, or red sequence fraction from counts of galaxies exhibiting distinct morphological features or stellar populations. However, two of the most widely-used techniques for estimating binomial confidence intervals — the ‘normal approximation’ and the Clopper & Pearson approach — are liable to misrepresent the degree of statistical uncertainty present under sampling conditions routinely encountered in astronomical surveys, leading to an ineffective use of the experimental data (and, worse, an inefficient use of the resources expended in obtaining that data). Hence, I provide here an overview of the fundamentals of binomial statistics with two principal aims: (I) to reveal the ease with which (Bayesian) binomial confidence intervals with more satisfactory behaviour may be estimated from the quantiles of the beta distribution using modern mathematical software packages (e.g.r, matlab, mathematica, idl, python); and (ii) to demonstrate convincingly the major flaws of both the ‘normal approximation’ and the Clopper & Pearson approach for error estimation.

The Effect of Hole Fraction on Viscosity in Atactic and Syndiotactic Polystyrenes

2015 ◽  
Vol 36 (10-11) ◽  
pp. 3239-3254 ◽  
Author(s):  
Fatma Sahin-Dinc ◽  
Andrea Sorrentino ◽  
Cumali Tav ◽  
Ugur Yahsi
Keyword(s):  
Hole Fraction

scholarly journals Interrelationships of Pressure-Dependent Hole Fraction and Elongational Viscosity in Polymer Melts

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Fatma Sahin-Dinc ◽  
Ugur Yahsi ◽  
Tomas Sedlacek
Keyword(s):  
High Pressures ◽  
Flow Behavior ◽  
Measurement Data ◽  
Elongational Flow ◽  
Elongational Viscosity ◽  
Viscosity Data ◽  
Cross Model ◽  
Elevated Pressures ◽  
The Cross ◽  
Hole Fraction

The elongational flow behavior of polyethylene, polypropylene, polystyrene, poly(methyl methacrylate), and polycarbonate, temperatures from 70 to 290 °C and pressures up to 70 MPa, is examined with the Yahsi-Dinc-Tav (YDT) model and its particular case known as the Cross model. The viscosity data employed in the range of 3-405 s-1 elongational rates were acquired from the literature at ambient and elevated pressures. The predictions and the fitting results of the proposed YDT model with the same measurement data are compared with the Cross model. The average absolute deviations of the viscosities predicted by the YDT model range from 0.54% to 9.44% at ambient and 1.95% to 6.28% at high pressures. Additionally, the linear formulations derived from the YDT model are employed to relate the viscosity with temperature and hole fraction (“thermooccupancy” function) at zero level of elongational rate and constant elongational rate along with constant elongational stress. The effects of the four viscosity parameters (such as transmission and activation energy coefficients in these equations) on the elongational viscosity are analyzed in detail and some conclusions on the structural differences for the polymers are discussed.

On the non-newtonian viscous behavior of polymer melts in terms of temperature and pressure-dependent hole fraction

2014 ◽  
Vol 131 (15) ◽  
pp. n/a-n/a ◽  
Author(s):  
Fatma Sahin Dinc ◽  
Tomas Sedlacek ◽  
Cumali Tav ◽  
Ugur Yahsi
Keyword(s):  
Polymer Melts ◽  
Temperature And Pressure ◽  
Hole Fraction

scholarly journals Constraining primordial black hole fraction at the galactic centre using radio observational data

2020 ◽  
Vol 497 (1) ◽  
pp. 1212-1216
Author(s):  
Man Ho Chan ◽  
Chak Man Lee
Keyword(s):  
Dark Matter ◽  
Gamma Ray ◽  
Minor Component ◽  
Cosmic Ray ◽  
Galactic Centre ◽  
Primordial Black Hole ◽  
Primordial Black Holes ◽  
Mass Distributions ◽  
Large Parameter Space ◽  
Hole Fraction

ABSTRACT Recent gamma-ray and cosmic-ray observations have put strong constraints on the amount of primordial black holes (PBHs) in our universe. In this paper, we use the archival radio data of the inner Galactic Centre to constrain the PBH to dark matter ratio for three different PBH mass distributions including monochromatic, lognormal, and power law. We show that the amount of PBHs only constitutes a very minor component of dark matter at the Galactic Centre for a large parameter space.

Microstructure and Mechanical Properties of Air Core Polymer Photonic Crystal Fibers

2011 ◽  
Vol 233-235 ◽  
pp. 3000-3004
Author(s):  
Hsi Hsin Chien ◽  
Kung Jeng Ma ◽  
Yun Peng Yeh ◽  
Choung Lii Chao
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystal Fiber ◽  
Optical Fibers ◽  
Photonic Crystal Fibers ◽  
Crystal Fiber ◽  
Microstructured Optical Fiber ◽  
Air Core ◽  
Crystal Fibers ◽  
Hole Fraction ◽  
Air Hole

Polymer based photonic crystal fibers with low cost manufacturability, and the mechanical and chemical flexibility offer key advantages over traditional silica based photonic crystal fibers. PMMA photonic crystal fiber was fabricated by stacking an array of PMMA capillaries to form a preform, and followed by fusing and drawing into fiber with a draw tower. The air hole diameter and fraction of photonic crystal fiber can be manipulated by the thickness of PMMA capillaries and drawing temperature. The measurement of mechanical properties was performed by universal testing machine. The air core guiding phenomena was observed in air-core PMMA photonic crystal fiber. The ultimate tensile strength of PMMA photonic crystal fiber increases with the increase of the air-hole fraction. The mechanical strengths of all the microstructured optical fibers are higher than those of traditional PMMA fibers. This can be attributed to the introduction of more cellular interfaces which hinder the crack propagation and hence improve the mechanical strength. The plastic extension of PMMA microstructured optical fiber decreases with the increase of the air-hole fraction. Overall, the mechanical flexibility of PMMA microstructured optical fiber is superior than that of traditional PMMA optical fibers.

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