Volume effects in solutions of polymethyl methacrylate in good solvents

Based on the contact angle prediction model of a traditional square column structure, the prediction models for wettability of a parallelogram square column structure (PSCS) on polymethyl methacrylate (PMMA) surface prepared by femtosecond laser were established. An experiment was conducted to analyze the rationality of the established complete wetting model and incomplete wetting model. It was found that the incomplete wetting prediction model of the square column structure was more in line with the actual situation. For PSCS, the length of both the long and short sides of the boss and the width of the groove exerted an impact on the contact angle prediction results. Under the condition that the length of the long and short sides of the boss remained unchanged and the groove width increased, the contact angle increased under complete wetting and incomplete wetting. In contrast, under the condition that the long side length of the boss and the groove width remained unchanged and the short side length of the boss increased, the contact angle increased under complete wetting but decreased under incomplete wetting. The maximum contact angle reached 135.65°, indicating that PSCS on PMMA surface enhanced the surface hydrophobicity of the material.

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Thermodynamic and Kinetic Characteristics of Combustion of Discrete Polymethyl Methacrylate Plates with Different Spacings in Concave Building Facades

Polymers ◽

10.3390/polym13010167 ◽

2021 ◽

Vol 13 (1) ◽

pp. 167

Author(s):

Weiguang An ◽

Lujun Peng ◽

Minglun Cai ◽

Kaiyang Hu ◽

Song Li ◽

...

Keyword(s):

Polymethyl Methacrylate ◽

Flame Spread ◽

Structure Factor ◽

Turning Point ◽

Fire Risk ◽

Flame Height ◽

Hazard Evaluation ◽

Spread Rate ◽

Building Facades ◽

Flame Spread Rate

Polymethyl methacrylate plates are widely applied to buildings, producing significant fire hazards. It lacks a theoretical basis for the fire risk assessment of polymethyl methacrylate in concave building facades. Therefore, experimental methods are used to investigate combustion characteristics of discrete polymethyl methacrylate plates in a concave building facade. Influences of fuel coverage and structure factor are investigated, which is scant in previous works. When structure factor is invariable, average flame height increases first and then decreases as fuel coverage increases, and the turning point is between 0.64 and 0.76. In total, three different patterns of pyrolysis front propagation are first observed for different fuel coverages. Flame spread rate first increases and then decreases as fuel coverage rises, and the turning point is also between 0.64 and 0.76. When fuel coverage is invariable, the flame spread rate first increases and then decreases with increasing structure factor, and the turning point is 1.2. A model for predicting the flame spread rate of discrete polymethyl methacrylate is also developed. The predicted values are consistent with experimental results. Fuel spread rate of discrete polymethyl methacrylate rises as the fuel coverage increases. The above results are beneficial for thermal hazard evaluation and fire safety design of polymethyl methacrylate used in buildings.

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Influence of adding nano / micro hydroxyapatite (HA) particles on tribological characteristics of polymethyl methacrylate (PMMA)

10.1063/5.0032990 ◽

2020 ◽

Author(s):

Nehad H. Jarboo’a ◽

Abdulhameed Raheem Alsarraf

Keyword(s):

Polymethyl Methacrylate ◽

Tribological Characteristics

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Does microwave and hydrogen peroxide disinfection reduce Candida albicans biofilm on polymethyl methacrylate denture surfaces?

Journal of Prosthetic Dentistry ◽

10.1016/j.prosdent.2021.02.012 ◽

2021 ◽

Author(s):

Ilse Verónica Martínez-Serna ◽

Marine Ortiz Magdaleno ◽

Juan Antonio Cepeda-Bravo ◽

Gabriel Fernando Romo-Ramírez ◽

Luis Octavio Sánchez-Vargas

Keyword(s):

Hydrogen Peroxide ◽

Candida Albicans ◽

Polymethyl Methacrylate

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More on the flavor dependence of mϱ/fπ

Journal of High Energy Physics ◽

10.1007/jhep07(2021)202 ◽

2021 ◽

Vol 2021 (7) ◽

Author(s):

Andrey Yu. Kotov ◽

Daniel Nogradi ◽

Kalman K. Szabo ◽

Lorinc Szikszai

Keyword(s):

Gauge Theory ◽

Symmetry Breaking ◽

Finite Volume ◽

Continuum Limit ◽

Low Energy ◽

Translational Symmetry ◽

Fundamental Representation ◽

Staggered Fermions ◽

Link Type ◽

Volume Effects

Abstract In previous work, [arXiv:1905.01909], we have calculated the mϱ/fπ ratio in the chiral and continuum limit for SU(3) gauge theory coupled to Nf = 2, 3, 4, 5, 6 fermions in the fundamental representation. The main result was that this ratio displays no statistically significant Nf-dependence. In the present work we continue the study of the Nf-dependence by extending the simulations to Nf = 7, 8, 9, 10. Along the way we also study in detail the Nf-dependence of finite volume effects on low energy observables and a particular translational symmetry breaking unphysical, lattice artefact phase specific to staggered fermions.

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