scholarly journals Interfacial Phenomena in Multi-Micro-/Nanolayered Polymer Coextrusion: A Review of Fundamental and Engineering Aspects

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 417
Author(s):  
Bo Lu ◽  
Huagui Zhang ◽  
Abderrahim Maazouz ◽  
Khalid Lamnawar
Keyword(s):  
High Performance ◽  
Interfacial Phenomena ◽  
Microstructural Development ◽  
Flow Conditions ◽  
Interfacial Instabilities ◽  
Reliable Technique ◽  
End Use ◽  
Continuous Fabrication ◽  
Interfacial Evolution ◽  
Laminar Flow Conditions

The multilayer coextrusion process is known to be a reliable technique for the continuous fabrication of high-performance micro-/nanolayered polymeric products. Using laminar flow conditions to combine polymer pairs, one can produce multilayer films and composites with a large number of interfaces at the polymer-polymer boundary. Interfacial phenomena, including interlayer diffusion, interlayer reaction, interfacial instabilities, and interfacial geometrical confinement, are always present during multilayer coextrusion depending on the processed polymers. They are critical in defining the microstructural development and resulting macroscopic properties of multilayered products. This paper, therefore, presents a comprehensive review of these interfacial phenomena and illustrates systematically how these phenomena develop and influence the resulting physicochemical properties. This review will promote the understanding of interfacial evolution in the micro-/nanolayer coextrusion process while enabling the better control of the microstructure and end use properties.

Velocity measurements close to the bed in a wave tank

1970 ◽  
Vol 42 (1) ◽  
pp. 111-123 ◽  
Author(s):  
J. F. A. Sleath
Keyword(s):  
Velocity Distribution ◽  
Vortex Formation ◽  
Reynolds Numbers ◽  
Flow Conditions ◽  
Velocity Measurements ◽  
Dominant Effect ◽  
Wave Tank ◽  
High Reynolds Numbers ◽  
High Reynolds ◽  
Laminar Flow Conditions

Measurements of the velocity distribution close to the bed have been made under laminar flow conditions in a wave tank. The classical solution for the velocity distribution was found to be valid when the bed was smooth, but considerable deviations between theory and experiment were observed with beds of sand. It is suggested that these deviations were caused by vortex formation around the grains of sand. The similarity between the velocity profiles obtained in these tests and those reported by other writers under supposedly turbulent conditions suggests that even at high Reynolds numbers vortex formation may continue to be the dominant effect in oscillatory boundary layers of this sort.

scholarly journals Theoretical evaluation of concentration time and storage coefficient with their application to major dam basins in Korea

2018 ◽  
Vol 19 (2) ◽  
pp. 644-652
Author(s):  
Chulsang Yoo ◽  
Jiho Lee ◽  
Eunsaem Cho
Keyword(s):  
Channel Length ◽  
Main Channel ◽  
Flow Conditions ◽  
Empirical Formulas ◽  
Theoretical Evaluation ◽  
Storage Coefficient ◽  
Concentration Time ◽  
Channel Slope ◽  
And Storage ◽  
Laminar Flow Conditions

Abstract This study theoretically evaluated the basin concentration time and storage coefficient with their empirical formulas available worldwide. The evaluation results were also validated in the application to major dam basins in Korea. The findings are summarized as follows. As a result of analytical analysis, the concentration time was found to be proportional to the main channel length under laminar flow conditions and to the square of it under turbulent flow conditions, but inversely proportional to the channel slope. It was also found that the storage coefficient and the concentration time are linearly but loosely related. Most empirical formulas for the concentration time concurred with the basic equation form, but just a few for the storage coefficient. Applications to major dam basins in Korea also showed that the concentration time agrees well with the result of theoretical analysis. However, the behavior of the storage coefficient varied much, basin by basin, indicating that additional factors may be needed to explain it.

A Mechanistic Study of Griseofulvin Dissolution into Surfactant Solutions under Laminar Flow Conditions

1997 ◽  
Vol 86 (10) ◽  
pp. 1132-1137 ◽  
Author(s):  
Venkatramana M. Rao ◽  
Mengfen Lin ◽  
Cynthia K. Larive ◽  
Marylee Z. Southard
Keyword(s):  
Laminar Flow ◽  
Mechanistic Study ◽  
Flow Conditions ◽  
Surfactant Solutions ◽  
Laminar Flow Conditions

Investigation of Airflow and Temperature Distribution in the Freezer Cabinet of a Domestic No-Frost Refrigerator

2009 ◽  
Author(s):  
Melike Nikbay ◽  
M. Berkay Acikgoz ◽  
Husnu Kerpicci
Keyword(s):  
Energy Consumption ◽  
Temperature Distribution ◽  
Uniform Temperature ◽  
Flow Conditions ◽  
Piv Measurements ◽  
Factors Affecting ◽  
Flow And Heat Transfer ◽  
Cfd Analyses ◽  
Off Time ◽  
Laminar Flow Conditions

Uniformity of temperature distribution in a loaded freezer cabinet is one of the most important factors affecting energy consumption of a refrigerator. Present study focuses on the airflow behavior and the temperature distribution inside the freezer compartment of a domestic no-frost refrigerator. Energy consumption increases in a freezer cabinet if the temperature difference between the warmest load package and average of all packages is high. The objective is to reduce the energy consumption by providing a uniform temperature distribution and also to keep the food fresh for a longer time. In this study, the air flow and heat transfer during on-time and off-time periods inside the freezer compartment is modeled by considering turbulent and laminar flow conditions in 3D transient CFD analyses. The initial and boundary conditions are provided from temperature controlled room and PIV measurements. The CFD analyses obtained are verified by experimental measurements.

scholarly journals Periodicity of Cell Attachment Patterns during Escherichia coli Biofilm Development

2003 ◽  
Vol 185 (18) ◽  
pp. 5632-5638 ◽  
Author(s):  
Konstantin Agladze ◽  
Debra Jackson ◽  
Tony Romeo
Keyword(s):  
Escherichia Coli ◽  
Laminar Flow ◽  
Biofilm Formation ◽  
Cell Attachment ◽  
Bacterial Biofilms ◽  
Flow Conditions ◽  
Biofilm Development ◽  
Complex Architecture ◽  
Activator Inhibitor ◽  
Laminar Flow Conditions

ABSTRACT The complex architecture of bacterial biofilms inevitably raises the question of their design. Microstructure of developing Escherichia coli biofilms was analyzed under static and laminar flow conditions. Cell attachment during early biofilm formation exhibited periodic density patterns that persisted during development. Several models for the origination of biofilm microstructure are considered, including an activator-inhibitor or Turing model.

scholarly journals Simulation of micromixing in a T-mixer under laminar flow conditions

2020 ◽  
Vol 222 ◽  
pp. 115706 ◽  
Author(s):  
Cláudio P. Fonte ◽  
David F. Fletcher ◽  
Pierrette Guichardon ◽  
Joelle Aubin
Keyword(s):  
Laminar Flow ◽  
Flow Conditions ◽  
Laminar Flow Conditions

scholarly journals Fabrication and Hypersonic Wind Tunnel Validation of a MEMS Skin Friction Sensor Based on Visual Alignment Technology

Sensors ◽  
2019 ◽  
Vol 19 (17) ◽  
pp. 3803
Author(s):  
Xiong Wang ◽  
Nantian Wang ◽  
Xiaobin Xu ◽  
Tao Zhu ◽  
Yang Gao
Keyword(s):  
Wind Tunnel ◽  
Laminar Flow ◽  
Turbulent Flow ◽  
Skin Friction ◽  
Flow Conditions ◽  
Friction Coefficients ◽  
Hypersonic Wind Tunnel ◽  
Laminar Flow Conditions ◽  
Turbulent Flow Conditions ◽  
Better Than

MEMS-based skin friction sensors are used to measure and validate skin friction and its distribution, and their advantages of small volume, high reliability, and low cost make them very important for vehicle design. Aiming at addressing the accuracy problem of skin friction measurements induced by existing errors of sensor fabrication and assembly, a novel fabrication technology based on visual alignment is presented. Sensor optimization, precise fabrication of key parts, micro-assembly based on visual alignment, prototype fabrication, static calibration and validation in a hypersonic wind tunnel are implemented. The fabrication and assembly precision of the sensor prototypes achieve the desired effect. The results indicate that the sensor prototypes have the characteristics of fast response, good stability and zero-return; the measurement ranges are 0–100 Pa, the resolution is 0.1 Pa, the repeatability accuracy and linearity are better than 1%, the repeatability accuracy in laminar flow conditions is better than 2% and it is almost 3% in turbulent flow conditions. The deviations between the measured skin friction coefficients and numerical solutions are almost 10% under turbulent flow conditions; whereas the deviations between the measured skin friction coefficients and the analytical values are large (even more than 100%) under laminar flow conditions. The error resources of direct skin friction measurement and their influence rules are systematically analyzed.

Sign in / Sign up

Export Citation Format

Share Document