scholarly journals CO2 Induced Foaming Behavior of Polystyrene near the Glass Transition

2017 ◽  
Vol 2017 ◽  
pp. 1-15
Author(s):  
Salah Al-Enezi
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Glass Transition ◽  
Dissolved Gas ◽  
Foaming Process ◽  
Foaming Behavior ◽  
Potential Applications ◽  
Model C ◽  
Parameter Values ◽  
Good Agreement

This paper examines the effect of high-pressure carbon dioxide on the foaming process in polystyrene near the glass transition temperature and the foaming was studied using cylindrical high-pressure view cell with two optical windows. This technique has potential applications in the shape foaming of polymers at lower temperatures, dye impregnation, and the foaming of polystyrene. Three sets of experiments were carried out at operating temperatures of 50, 70, and 100°C, each over a range of pressures from 24 to 120 bar. Foaming was not observed when the polymer was initially at conditions below Tg but was observed above Tg. The nucleation appeared to occur randomly leading to subsequent bubble growth from these sites, with maximum radius of 0.02–0.83 mm. Three models were applied on the foaming experimental data. Variable diffusivity and viscosity model (Model C) was applied to assess the experimental data with the WLF equation. The model shows very good agreement by using realistic parameter values. The expansion occurs by diffusion of a dissolved gas from the supersaturated polymer envelope into the bubble.

scholarly journals Phase Behavior at High Pressure of the Ternary System: CO2, Ionic Liquid and Disperse Dye

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Helen R. Mazzer ◽  
José C. O. Santos ◽  
Vladimir F. Cabral ◽  
Claudio Dariva ◽  
Marcos H. Kunita ◽  
...  
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
High Pressure ◽  
Phase Behavior ◽  
Ternary Systems ◽  
High Pressure Phase Behavior ◽  
Phase Transition Pressure ◽  
Binary And Ternary Systems ◽  
Pressure Phase ◽  
Good Agreement

High pressure phase behavior experimental data have been measured for the systems carbon dioxide (CO2) + 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim] [PF6]) and carbon dioxide (CO2) + 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim] [PF6]) + 1-amino-2-phenoxy-4-hydroxyanthraquinone (C.I. Disperse Red 60). Measurements were performed in the pressure up to 18 MPa and at the temperature (323 to 353 K). As reported in the literature, at higher concentrations of carbon dioxide the phase transition pressure increased very steeply. The experimental data for the binary and ternary systems were correlated with good agreement using the Peng-Robinson equation of state. The amount of water in phase behavior of the systems was evaluated.

Effect of Chain Morphology and Carbon-Nanotube Additives on the Glass Transition Temperature of Polyethylene

2013 ◽  
Vol 23 ◽  
pp. 16-23 ◽  
Author(s):  
S. Herasati ◽  
H.H. Ruan ◽  
Liang Chi Zhang
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Glass Transition ◽  
Carbon Nanotube ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Md Simulation ◽  
Md Simulations ◽  
Crystalline Polymers ◽  
Good Agreement

Glass transition temperature Tg is the most important parameter affecting the mechanical properties of amorphous and semi-crystalline polymers. However, the atomistic origin of glass transition is not yet well understood. Using Polyethylene (PE) as an example, this paper investigates the glass transition temperature Tg of PE with the aid of molecular dynamics (MD) simulation. The effects of PE chain branches, crystallinity and carbon-nanotube (CNT) additives on the glass transition temperature are analyzed. The MD simulations render a good agreement with the relevant experimental data of semi-crystalline PE and show the significant effects of crystallinity and addition of CNTs on Tg.

High-Pressure Elastic Constant of Some Materials of Earth’s Mantle

2016 ◽  
Vol 71 (5) ◽  
pp. 433-437
Author(s):  
Quan Liu
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Theoretical Model ◽  
Elastic Behaviour ◽  
Exponential Relationship ◽  
Earth’S Mantle ◽  
Simple Theoretical Model ◽  
Volume Dependence ◽  
Theoretical Investigations ◽  
Good Agreement

AbstractIn the present work, an exponential relationship for the volume dependence of the Anderson–Grüneisen parameter along isotherm and the formulation derived from Tallon’s model have been used to develop a simple theoretical model for the elastic constants as a function of pressure. Applying it to some materials of earth’s mantle at different pressure ranges, the calculated results are in good agreement with the earlier theoretical investigations and available experimental data and thus show that our theory can be applied for predicting the elastic behaviour of earth materials at high pressure.

NANOMATERIALS UNDER HIGH TEMPERATURE AND HIGH PRESSURE

2010 ◽  
Vol 24 (26) ◽  
pp. 2647-2657 ◽  
Author(s):  
R. KUMAR ◽  
UMA D. SHARMA ◽  
MUNISH KUMAR
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Thermal Expansion ◽  
High Temperature ◽  
Constant Pressure ◽  
Effect Of Temperature ◽  
Effect Of Pressure ◽  
Approaches To Study ◽  
Theory And Experiment ◽  
Good Agreement

Two different approaches to study thermal expansion and compression of nanosystems are unified, which have been treated quite independently by earlier workers. We provide the simple theoretical analysis, which demonstrates that these two approaches may be unified into a single theory, viz. one can be derived from other. It is concluded that there is a single theory in the place of two different approaches. To show the real connection with the nanomaterials, we study the effect of temperature (at constant pressure), the effect of pressure (at constant temperature) as well as the combined effect of pressure and temperature. We have considered different nanomaterials viz. carbon nanotube, AlN , Ni , 80 Ni –20 Fe , Fe – Cu , MgO , CeO 2, CuO and TiO 2. The results obtained are compared with the available experimental data. A good agreement between theory and experiment demonstrates the validity of the present approach.

Analysis of the Creep Behaviour of Polypropylene

2005 ◽  
Vol 480-481 ◽  
pp. 175-180 ◽  
Author(s):  
José Reinas Dos Santos André ◽  
José Joaquim Cruz Pinto
Keyword(s):  
Experimental Data ◽  
Tensile Stress ◽  
Creep Behaviour ◽  
Retardation Time ◽  
Creep Data ◽  
Physical Mechanisms ◽  
Molecular Scale ◽  
Parameter Values ◽  
Different Levels ◽  
Good Agreement

In this work, creep data for a polypropylene (PP) were obtained at different levels of tensile stress and temperature, and were then analysed in the light of a model developed, which is based on physical mechanisms (at the molecular scale) responsible for the material’s behaviour, considering that a minimum retardation time does exist. The model yields very good agreement with the experimental data and physically meaningful theoretical parameter values.

scholarly journals Applicability of Different Isothermal EOS at Nanomaterials

2013 ◽  
Vol 2013 ◽  
pp. 1-9
Author(s):  
Deepika P. Joshi ◽  
Anjali Senger
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Pressure Range ◽  
Theoretical Study ◽  
Isothermal Bulk Modulus ◽  
Relative Compression ◽  
Experimental Values ◽  
Murnaghan Equation ◽  
Two Parameter ◽  
Good Agreement

The present study explains the behaviour of nanomaterials such as AlN, CdSe, Ge, WC, and Ni- and Fe-filled-MWCNTs under high pressure. Among the number of isothermal EOSs available, we prefer only two parameter-based isothermal equations (i.e., Murnaghan equation, usual Tait's equation, Suzuki equation and Shanker equation). The present work shows the theoretical study of thermo-elastic properties especially relative compression (V/V0), isothermal bulk modulus (KP/K0), and compressibility (αP/α0) of nanomaterials. After comparing all formulations with available experimental data, we conclude that pressure dependence of relative compression (V/V0) for the nanomaterials, are in good agreement for all the equations at lower pressure range. At higher pressure range, Suzuki and Shanker formulations show some deviation from experimental values.

Springback Analysis for Metal-Polymer-Metal Laminates

2003 ◽  
Author(s):  
Li Liu ◽  
Jyhwen Wang
Keyword(s):  
Experimental Data ◽  
Sheet Metal ◽  
Shape Control ◽  
Analytical Approach ◽  
Laminated Structure ◽  
Flat Sheet ◽  
Potential Applications ◽  
Polymer Metal ◽  
Metal Polymer ◽  
Good Agreement

Metal-polymer-metal laminate is an emerging material that has many potential applications. The laminated structure consists of two outer layers of sheet metal and a polymeric center core. The material offers an excellent sound deadening properties and is being introduced to applications where noise reduction is desired. Part manufacturing for laminates involves converting a flat sheet into a deformed body. Springback has been a major concern in shape control. While bending of a single layered sheet metal does not exhibit significant sidewall curl, the problem is pronounced in bending laminates. This paper presents an analytical approach to predict springback and sidewall curl of laminates due to simple bending. Based on the models, springback factor Ks is calculated. It is shown that the prediction is in good agreement with the published experimental data.

Numerical and Experimental Investigation As Applied to Effects of Labyrinth-Type Casing Treatments on Performance of High-Loaded Compressor First Stage

2018 ◽  
Author(s):  
V. I. Mileshin ◽  
V. V. Zhdanov ◽  
A. M. Petrovitchev
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Pressure Ratio ◽  
Turbulence Models ◽  
Lower Efficiency ◽  
Stall Margin ◽  
Casing Treatment ◽  
Smooth Flow ◽  
Casing Treatments ◽  
Good Agreement

In connection with the development of a new family of high-pressure HPC with ultra-high pressure ratio and the number of stages 10–11, a special attention should be paid to the development of the first high-load stage, because compressor performance directly depends on its excellence. Despite the fact that the stage at nominal rotational speeds can have optimal performance, stall margins at intermediate rotational speeds can decrease because of a sizable IGV closure. One of the ways to increase stall margins is the use of labyrinth-type casing treatments. The Stage “A-1” studied in this work is a full-scale first stage in a six-stage high-pressure compressor (HPC) for a core demonstrator. The primary design task for the labyrinth-type casing treatment (CT) is to keep performance at design rotational speeds (n = 100%) or improve them, if possible, and increase stall margins at intermediate speeds (n = 70% and n = 80%). The labyrinth-type CT consisting of 3 circumferential grooves located above the middle of the blade chord projection is specially designed and manufactured for this stage. Our computations show that the use of the labyrinth-type CT leads to a shift of performance towards higher airflow and efficiency that is a good agreement with experimental data. An increase in stall margins without changes in efficiency is found by calculations, whereas the test, on the contrary, shows no influence on stall margins and an increase in efficiency by ∼1.5% (the same as at rated speeds). Both investigated turbulence models (SST and k-ε) do not provide good agreement with the experimental data. The SST model captures CT influence, but decreases stall margin. The k-ε model show agreement with the test in stall margin, but cannot capture CT influence. In addition, both models show lower efficiency compared with the experimental data. To verify the NUMECA Fine Turbo (version 11.1) mathematical model and numerical method, calculated and experimental characteristics of the Stage A-1 with a smooth flow passage and a labyrinth-type CT are compared. The NUMECA Autogrid 5 grid generator is used to build the grid.

scholarly journals Depressurization System by Coiled Pipes Applied to a High Pressure Process: Experimental Results and Modeling

2017 ◽  
Vol 11 (1) ◽  
pp. 17-32
Author(s):  
J. M. Benjumea ◽  
J. Sánchez-Oneto ◽  
J. R. Portela ◽  
E. J. Martínez de la Ossa
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Pressure Drop ◽  
Friction Factor ◽  
Pilot Plant ◽  
Single Step ◽  
Experimental Results ◽  
Industrial Scale ◽  
High Pressure Process ◽  
Good Agreement

Background:The use of backpressure regulator valves is widespread in high-pressure processes both at laboratory and pilot plant scales, but being a single step for effluent depressurization, such valves may have some limitations at industrial scale. In an effort to improve the depressurization step, this work studies a system based on the pressure drop of a fluid that circulates through coiled pipes.Method:The equipment, based on three series of variable length coiled pipes, was installed to achieve depressurization of 240 bars in a SCWO pilot plant.Results:The experimental results were compared with those obtained by the modeling carried out using different friction factor correlations from the literature.Conclusion:Among all the correlations tested, the Lockhart–Martinelli correlation showed the best agreement with experimental data. However, it was necessary to obtain an appropriate C parameter to achieve a good agreement with experimental data.

Thermodynamics of supercooled liquid silicon and its glass transition

2002 ◽  
Vol 754 ◽  
Author(s):  
Caetano R. Miranda ◽  
Alex Antonelli
Keyword(s):  
Experimental Data ◽  
Glass Transition ◽  
Interatomic Potential ◽  
Configurational Entropy ◽  
Supercooled Liquid ◽  
Scaling Method ◽  
Kauzmann Temperature ◽  
Liquid Phases ◽  
Atomic Interactions ◽  
Good Agreement

ABSTRACTThe thermodynamic properties of various phases of silicon, namely, crystalline, amorphous, and liquid, have been studied using the Reversible Scaling method within Monte Carlo simulations. The recently proposed Environment Dependent Interatomic Potential was employed to model the atomic interactions. The calculated Gibbs free energy and entropy of both crystalline and liquid phases are in good agreement with available experimental data. The glass transition is continuous, taking place at 1150 K. We have also determined the Kauzmann temperature, TK = 955 K, the thermodynamic fragility, F3/4 = 0.64, which indicates a fragile thermodynamic character to l-Si, and the configurational entropy of the amorphous phase, Sconf ≈ 1.2 kB/atom.

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