scholarly journals Assessment of Morphological, Physical, Thermal, and Thermal Conductivity Properties of Polypropylene/Lignosulfonate Blends

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 543
Author(s):  
Mariane Schneider ◽  
Noriê Finimundi ◽  
Maria Podzorova ◽  
Petr Pantyukhov ◽  
Matheus Poletto
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stability ◽  
Flame Retardant ◽  
Thermal Conductivity Coefficient ◽  
Theoretical Models ◽  
Sodium Lignosulfonate ◽  
Reactive Component ◽  
Experimental Values ◽  
Potential Use ◽  
Good Agreement

Lignosulfonate is a cheap material available in large quantities obtained as a byproduct of paper and cellulose. In this work, blends of polypropylene (PP) and sodium lignosulfonate (LGNa) were developed to evaluate the potential use of lignosulfonate as a lightweight, thermal insulation and flame retardant material. The blends were obtained by mixing in a torque rheometer and molded after compression. The blend proprieties were evaluated by physical, morphological, thermal, thermal conductivity, and flammability tests. The measured values were compared with theoretical models. The results indicated that a heterogeneous blend with a higher number of separated domains is formed when the LGNa content increases from 10 to 40 wt%. In addition, the density and thermal conductivity coefficient of the blends studied are not affected by the addition of LGNa. However, when the LGNa content in the blend exceeds 20 wt% the thermal stability and flame retardant proprieties are considerably reduced. The theoretical models based on the rule of mixtures showed a good agreement with the experimental values obtained from blend density, thermal conductivity, and thermal stability. In general, lignosulfonate tested in this work shows potential to be used as a reactive component in polymer blends.

scholarly journals Relationship between the Transport Coefficients of Polar Substances and Entropy

Entropy ◽  
2019 ◽  
Vol 22 (1) ◽  
pp. 13
Author(s):  
Ivan Anashkin ◽  
Sergey Dyakonov ◽  
German Dyakonov
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Diffusion Coefficient ◽  
High Pressures ◽  
Thermal Conductivity Coefficient ◽  
Good Description ◽  
Transport Coefficients ◽  
Viscosity Coefficient ◽  
Wide Region ◽  
Good Agreement

An expression is proposed that relates the transport properties of polar substances (diffusion coefficient, viscosity coefficient, and thermal conductivity coefficient) with entropy. To calculate the entropy, an equation of state with a good description of the properties in a wide region of the state is used. Comparison of calculations based on the proposed expressions with experimental data showed good agreement. A deviation exceeding 20% is observed only in the region near the critical point as well as at high pressures.

Dual Role of Nanoparticles in the Thermal Conductivity Enhancement of Nanoparticle Suspensions

2005 ◽  
Author(s):  
Calvin H. Li ◽  
G. P. Peterson
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Brownian Motion ◽  
Theoretical Models ◽  
Conductivity Enhancement ◽  
Nanoparticle Suspensions ◽  
The Difference ◽  
Physical Phenomena ◽  
Good Agreement

Experimental evidence exists that the addition of a small quantity of nanoparticles to a base fluid, can have a significant impact on the effective thermal conductivity of the resulting suspension. The causes for this are currently thought to be due to a combination of two distinct mechanisms. The first is due to the change in the thermophysical properties of the suspension, resulting from the difference in the thermal conductivity of the fluid and the particles, and the second is thought to be due to the transport of thermal energy by the particles, due to the Brownian motion of the particles. In order to better understand these phenomena, a theoretical model has been developed that examines the effect of the Brownian motion. In this model, the well-known approach first presented by Maxwell, is combined with a new expression that incorporates the effect of the Brownian motion and describes the physical phenomena that occurs because of it. The results indicate that the enhanced thermal conductivity may not in fact be due to the transport of energy by the particles, but rather, due to the stirring motion caused by the movement of the nanoparticles which enhances the heat transfer within the fluid. The resulting model shows good agreement when compared with the existing experimental data and perhaps more importantly helps to explain the trends observed from a fundamental physical perspective. In addition, it provides a possible explanation for the differences that have been observed between the previously obtained experimental data, the predictions obtained from Maxwell’s equation and the theoretical models developed by other investigators.

Influence of the Contact Pressure on the Rolling Resistance Moments in Dry Ball-Race Contacts

2014 ◽  
Vol 658 ◽  
pp. 305-310
Author(s):  
Alina Corina Dumitrascu ◽  
Gelu Ianus ◽  
Dumitru Olaru
Keyword(s):  
Theoretical Model ◽  
Contact Pressure ◽  
Rotational Speed ◽  
Ball Bearing ◽  
Rolling Resistance ◽  
Theoretical Models ◽  
Hertzian Contact ◽  
Experimental Methodology ◽  
Experimental Values ◽  
Good Agreement

Based on a theoretical model and an experimental methodology for defining the rolling resistance moments in a modified thrust ball bearing having only 3 balls, the authors experimentally investigated the influence of the Hertzian contact pressure on rolling resistance moments between a ball and a race. The experiments were realized with balls having diameters between 1.588 mm and 4.762 mm with maximum Hertzian pressure between 0.2GPa and 1GPa, operating for rotational speed between 60rpm to 210 rpm. The experiments evidenced that the measured values of the rolling resistance moments have higher values that the theoretical hysteresis and curvature rolling resistance moments for low contact pressure. By increasing of the contact pressure to 1GPa the experimental values for rolling resistance moments are in good agreement with the theoretical models.

scholarly journals A NEW TYPE OF BREAKWATER UTILIZING AIR COMPRESSIBILITY

1988 ◽  
Vol 1 (21) ◽  
pp. 172 ◽  
Author(s):  
Masaaki Ikeno ◽  
Naokatsu Shimoda ◽  
Koichiro Iwata
Keyword(s):  
Energy Dissipation ◽  
Wave Energy ◽  
Theoretical Models ◽  
Pressure Variation ◽  
Wave Energy Dissipation ◽  
Air Chamber ◽  
New Type ◽  
Experimental Values ◽  
Better Than ◽  
Good Agreement

This paper is to investigate both theoretically and experimentally the wave energy dissipation and air-pressure variation of a new type of breakwater having a pressurized air-chamber and two buoyancy tanks. The theoretical models are developed in this paper and they are shown to be in good agreement with experimental values. The new type of breakwater proposed in this paper is pointed out to attenuate the transmitted wave much better than the rectangular-shaped and concave-shaped breakwaters without the air-chamber.

scholarly journals Theoretical Evaluation of Ultrasonic Velocities of Binary Liquid Mixtures of 1-Bromopropane in Chlorobenzene at 303.15, 308.15, 313.15 and 318.15 K

2014 ◽  
Vol 30 ◽  
pp. 9-17
Author(s):  
Ch. Praveen Babu ◽  
G. Pavan Kumar ◽  
B. Nagarjun ◽  
K. Samatha
Keyword(s):  
Intermolecular Interactions ◽  
Theoretical Models ◽  
Liquid Mixtures ◽  
Binary Liquid Mixtures ◽  
Ultrasonic Velocities ◽  
Theoretical Evaluation ◽  
Binary Liquid ◽  
Different Temperatures ◽  
Experimental Values ◽  
Good Agreement

Theoretical velocities of binary liquid mixtures of 1-bromopropane with chlorobenzene at 2 MHz and four different temperatures 303.15, 308.15, 313.15 and 318.15 K, have been evaluated as a function of concentration and temperature. The experimental values are compared with theoretical models of liquid mixtures such as Nomoto, Van Dael-Vangeel, Impedance Relation, Rao’s Specific Velocity Method, Junjie’s relations and Free Length Theory. In the chosen system there is a good agreement between experimental and theoretical values calculated by Nomoto’s theory. The deviation in the variation of U2exp/U2imx from unity has also been evaluated for explaining the non ideality in the mixtures. The results are explained in terms of intermolecular interactions occurring in these binary liquid mixtures.

scholarly journals INVESTIGATION OF THERMAL CONDUCTIVITY OF LUFFA AND LUFFA-COIR REINFORCED EPOXY COMPOSITES

2020 ◽  
Vol 8 (12) ◽  
pp. 69-79
Author(s):  
K. Anbukarasi ◽  
S. Imran Hussain ◽  
S. Kalaiselvam
Keyword(s):  
Thermal Conductivity ◽  
Volume Fraction ◽  
Hybrid Composites ◽  
Theoretical Models ◽  
Epoxy Composites ◽  
Coir Fiber ◽  
Fiber Volume ◽  
Experimental Values ◽  
Thermal Stability Of ◽  
Guarded Heat Flow Meter

Thermal behavior of luffa and coir reinforced epoxy composites have been evaluated for a constant total fiber volume fraction 0.4Vf by varying the ratio of luffa and coir fiber. Thermal conductivity of luffa-epoxy and luffa-coir reinforced epoxy composite was studied experimentally and analytically in terms of fiber size and fiber volume. Thermal conductivity of composites was investigated experimentally by a guarded heat flow meter method. The experimental results at different volume fraction were compared with three theoretical models. The composite C has the lowest thermal conductivity of 0.206 W/mk with 0.81 % of voids. The experimental values of thermal conductivity of hybrid composites are the good correlation with the Maxwell and Maxwell-Eucken models. As in a case of 0.4 Vf of luffa-epoxy composites these values are closer to the rule of mixture models. The thermal stability of the composites was investigated by thermogravimetric analysis. This result reveals that the hybridization of luffa and coir with epoxy allows a significantly improved insulation ability of the composites.

scholarly journals Experimental and Theoretical Evaluation of Ultrasonic Velocities of Binary Liquid Mixtures of Anisaldehyde and Toluene at Different Temperatures

2011 ◽  
Vol 8 (3) ◽  
pp. 977-981
Author(s):  
CH. Srinivasu ◽  
K. Narendra ◽  
CH. Kalpana
Keyword(s):  
Ultrasonic Velocity ◽  
Theoretical Models ◽  
Liquid Mixtures ◽  
Binary Liquid Mixtures ◽  
Ultrasonic Velocities ◽  
Theoretical Evaluation ◽  
Binary Liquid ◽  
Different Temperatures ◽  
Experimental Values ◽  
Good Agreement

Theoretical velocities of binary liquid mixtures of anisaldehyde with toluene at 303.15, 308.15, 313.15 and 318.15 K have been evaluated by using theoretical models of liquid mixtures such as Nomoto, Van Dael-Vangeel, Schaff’s collision factor theory and Junjie’s relations. Density and ultrasonic velocity of these mixtures have also been measured as a function of concentration and temperature and the experimental values are compared with the theoretical values. A good agreement has been found between experimental and Nomoto’s theoretical ultrasonic velocities. The results are explained in terms of intermolecular interactions occurring in these binary liquid mixtures.

Lattice Boltzmann Modeling of the Effective Thermal Conductivity for Complex Structured Multiphase Building Materials

2015 ◽  
Vol 1119 ◽  
pp. 694-699 ◽  
Author(s):  
Mazhar Hussain ◽  
Shakeel Ahmad ◽  
Wen Quan Tao
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Lattice Boltzmann ◽  
Building Materials ◽  
Present Model ◽  
High Efficiency ◽  
Theoretical Models ◽  
Random Generation ◽  
Proposed Model ◽  
Experimental Values

The effective thermal conductivity is an important parameter used to predict the thermal performance analysis of complex structured porous building materials. The observation of porous structure of building materials on REV (representative elementary volume) scale showed that pores can be classified into meso and macro pores. In contrast to the traditional models usually used for the (macro-meso) pore connection , a new numerical random generation macro-meso pores (RGMMP) method, based on geometrical and morphological information acquired from measurements or experimental calculations, is proposed here. Along with proposed structure generating tool RGMMP a high efficiency LBM, characterized with the energy conservation and appropriate boundary conditions at numerous interfaces in the complex system, for the solution of the governing equation is described which yields a powerful numerical tool to obtain accurate solutions. Then present model is validated with some theoretical and experimental values of effective thermal conductivity of typical building materials. The comparison of present model and experimental results shows that the proposed model agrees much better with the experimental data than the traditional theoretical models. Therefore, the present model is not limited to the described building materials but can also be used for predicting the effective thermal conductivity of any type of complex structured building materials.

scholarly journals Recovery of microstructure properties: random variability of soil solid thermal conductivity

2016 ◽  
Vol 38 (1) ◽  
pp. 99-107 ◽  
Author(s):  
Damian Stefaniuk ◽  
Adrian Różański ◽  
Dariusz Łydżba
Keyword(s):  
Thermal Conductivity ◽  
Probability Density ◽  
Thermal Conductivity Coefficient ◽  
Back Analysis ◽  
Probability Density Functions ◽  
Laboratory Results ◽  
Random Variability ◽  
Computational Micromechanics ◽  
Good Agreement ◽  
Thermal Conductivities

Abstract In this work, the complex microstructure of the soil solid, at the microscale, is modeled by prescribing the spatial variability of thermal conductivity coefficient to distinct soil separates. We postulate that the variation of thermal conductivity coefficient of each soil separate can be characterized by some probability density functions: fCl(λ), fSi(λ), fSa(λ), for clay, silt and sand separates, respectively. The main goal of the work is to recover/identify these functions with the use of back analysis based on both computational micromechanics and simulated annealing approaches. In other words, the following inverse problem is solved: given the measured overall thermal conductivities of composite soil find the probability density function f(λ) for each soil separate. For that purpose, measured thermal conductivities of 32 soils (of various fabric compositions) at saturation are used. Recovered functions f(λ) are then applied to the computational micromechanics approach; predicted conductivities are in a good agreement with laboratory results.

Alpha particle preformation factor of spherical nuclei for 67 ≤Z ≤91

2019 ◽  
Vol 34 (05) ◽  
pp. 1950039 ◽  
Author(s):  
S. S. Hosseini ◽  
H. Hassanabadi ◽  
Dashty T. Akrawy
Keyword(s):  
Alpha Particle ◽  
Scaling Law ◽  
Analytical Formula ◽  
Theoretical Models ◽  
Alpha Decay ◽  
Proximity Potential ◽  
Spherical Nuclei ◽  
Experimental Values ◽  
Semi Empirical ◽  
Good Agreement

In this paper, alpha decay half-lives of spherical nuclei in the range [Formula: see text] are studied by considering the Coulomb and proximity potential model (CPPM) and calculating the alpha particle preformation factor. Comparisons are made to existing data in the literature. The half-lives are compared to the experimental values and also with the existing theoretical models, the analytical formula of Royer (R) and also within the modified analytical formula of Royer (MR) and New Akrawy–Poenaru Formula (AKRE) by Akrawy and Poenaru and the semi-empirical model based on fission theory (SemFIS) of Poenaru et al., the Universal Decay Law (UDL) of Qi et al., the Scaling Law of Brown (SLB), the Scaling Law of Horoi et al. (SLH). Compared with the experimental alpha half-lives, it can be found that the half-lives obtained using our formalism is in good agreement with the experimental data.

Sign in / Sign up

Export Citation Format

Share Document