scholarly journals Morphology and Rheology of Nanofilled PP / PVA Blends

2017 ◽  
Vol 54 (4) ◽  
pp. 735-739 ◽  
Author(s):  
Natalia Rezanova ◽  
Yurii Budash ◽  
Viktoriia Plavan ◽  
Olena Ishchenko ◽  
Viktoriia Bulakh
Keyword(s):  
Sodium Oleate ◽  
Effective Viscosity ◽  
Formation Processes ◽  
Ternary Blends ◽  
Longitudinal Deformation ◽  
Dispersion Degree ◽  
Phase Type ◽  
The Matrix ◽  
Mixing Method ◽  
Nanoparticle Additives

The influence of Ag/SiO2 as nanofiller and sodium oleate as compatibilizer and their mixtures on the patterns flow and structure formation processes in thermodynamically incompatible polypropylene/plasticized polyvinylalcohol (PP / PVA) systems were studied. It is found that the change in the sequence of mixing the ingredients of the composition allows adjusting the morphology phase type due to the predominant localization of nanoparticle additives in the melt amount of a component or on the border of phase separation. Injection of Ag/SiO2 to melt PP increases dispersion degree and homogeneity of its distribution in the matrix. Simultaneous use of nanoadditive and sodium oleate as compatibilizer improves the connections between the polymers and promotes thinner and more homogeneous dispersion of the particles of the dispersed phase. It is shown that the effective viscosity of melt nanofilled system is determined by components mixing method: viscosity of melt blend increases when the additive is localized predominantly in the PVA and decreases with the prior injection of PP. The nature of the flow for all researched compositions obeys a power law and almost does not depend on the method of mixing. The ability of the longitudinal deformation of ternary blends is deteriorating, but remains sufficient for their processing. Combining nanoadditive with compatibilizer promotes increased elasticity and the melt spinnability of modified blends.

scholarly journals The Algebraic Degree of Phase-Type Distributions

2010 ◽  
Vol 47 (03) ◽  
pp. 611-629
Author(s):  
Mark Fackrell ◽  
Qi-Ming He ◽  
Peter Taylor ◽  
Hanqin Zhang
Keyword(s):  
Lower Bound ◽  
Upper Bound ◽  
Polynomial Algorithm ◽  
Algebraic Degree ◽  
Nonnegative Matrices ◽  
Stieltjes Transform ◽  
Special Cases ◽  
Phase Type ◽  
Phase Type Distributions ◽  
The Matrix

This paper is concerned with properties of the algebraic degree of the Laplace-Stieltjes transform of phase-type (PH) distributions. The main problem of interest is: given a PH generator, how do we find the maximum and the minimum algebraic degrees of all irreducible PH representations with that PH generator? Based on the matrix exponential (ME) order of ME distributions and the spectral polynomial algorithm, a method for computing the algebraic degree of a PH distribution is developed. The maximum algebraic degree is identified explicitly. Using Perron-Frobenius theory of nonnegative matrices, a lower bound and an upper bound on the minimum algebraic degree are found, subject to some conditions. Explicit results are obtained for special cases.

scholarly journals Exploring the Capability of HAADF-STEM Techniques to Characterize Graphene Distribution in Nanocomposites by Simulations

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
N. Baladés ◽  
D. L. Sales ◽  
M. Herrera ◽  
A. M. Raya ◽  
J. C. Hernández-Garrido ◽  
...  
Keyword(s):  
Electron Tomography ◽  
Carbon Matrix ◽  
Reconstruction Algorithm ◽  
Dark Field ◽  
Graphene Layers ◽  
Transmission Electron ◽  
Dispersion Degree ◽  
Scanning Transmission ◽  
The Matrix ◽  
Annular Dark Field

This paper explores the capability of scanning transmission electron microscopy (STEM) techniques in determining the dispersion degree of graphene layers within the carbon matrix by using simulated high-angle annular dark-field (HAADF) images. Results ensure that unmarked graphene layers are only detectable if their orientation is parallel to the microscope beam. Additionally, gold-marked graphene layers allow evaluating the dispersion degree in structural composites. Moreover, electron tomography has been demonstrated to provide truthfully 3D distribution of the graphene sheets inside the matrix when an appropriate reconstruction algorithm and 2D projections including channelling effect are used.

Characterization of Layered Double Hydroxide Modified with Sodium Dodecyl Sulfate and its Dispersion in Polyethylene

2013 ◽  
Vol 591 ◽  
pp. 138-141
Author(s):  
Zhi Dong Han ◽  
Xin Ke Zhang ◽  
Yue Wang ◽  
Zheng Quan Jiang ◽  
Peng Wang
Keyword(s):  
Sodium Dodecyl Sulfate ◽  
Layered Double Hydroxide ◽  
Sodium Dodecyl ◽  
Melt Blending ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Dodecyl Sulfate ◽  
The Matrix ◽  
Mixing Method ◽  
Double Hydroxide

Mg-Al layered double hydroxide (LDH) was modified with sodium dodecyl sulfate (SDS) by regeneration method. The structure of modified LDH (SDS-LDH) was investigated by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The composites of SDS-LDH and polyethylene (PE) were prepared by melt blending and solution mixing method with maleated PE (PEgMA) as compatibilizer. The structure of the composites and the dispersion of SDS-LDH in the matrix were investigated by XRD and transmission electron microscopy (TEM), respectively. The results reveal that SDS was successfully intercalated into the interlayer space of LDH. SDS-LDH was hardly exfoliated in PE/PEgMA by melt blending. The nanocomposites of PE/(PEgMA/SDS-LDH) were successfully prepared by melt blending PE with SDS-LDH/PEgMA master-batch obtained by solution mixing. Homogeneous dispersion of SDS-LDH in the matrix was observed by TEM.

scholarly journals Erlangian Approximations for Finite-Horizon Ruin Probabilities

2002 ◽  
Vol 32 (2) ◽  
pp. 267-281 ◽  
Author(s):  
Soren Asmussen ◽  
Florin Avram ◽  
Miguel Usabel
Keyword(s):  
Ruin Probability ◽  
Risk Model ◽  
Fluid Model ◽  
Ruin Probabilities ◽  
Approximation Procedure ◽  
Exponential Form ◽  
Probability Of Ruin ◽  
Phase Type ◽  
The Matrix ◽  
The Mean

AbstractFor the Cramér-Lundberg risk model with phase-type claims, it is shown that the probability of ruin before an independent phase-type time H coincides with the ruin probability in a certain Markovian fluid model and therefore has an matrix-exponential form. When H is exponential, this yields in particular a probabilistic interpretation of a recent result of Avram & Usabel. When H is Erlang, the matrix algebra takes a simple recursive form, and fixing the mean of H at T and letting the number of stages go to infinity yields a quick approximation procedure for the probability of ruin before time T. Numerical examples are given, including a combination with extrapolation.

Positron Studies of Defects in Nitrogen and Carbon Implanted Titanium

1998 ◽  
Vol 527 ◽  
Author(s):  
M. Soltani-Farshi ◽  
H. Baumann ◽  
W. Anwand ◽  
G. Brauer ◽  
P.G. Coleman ◽  
...  
Keyword(s):  
Defect Formation ◽  
Positron Beam ◽  
Formation Processes ◽  
Slow Positron ◽  
The Matrix ◽  
Matrix Lattice ◽  
Hydrogen Accumulation ◽  
Cp Ti ◽  
Modification Of Materials ◽  
Beam Technique

ABSTRACTModification of materials by ion beams creates defects and defect formation processes. The implantation of nitrogen into titanium influences the hydrogen content in this metal. Hydrogen accumulation enhances hydrogenations in the implanted region. This effect may have important consequences, because excessive hydrogen accumulation generally leads to precipitating hydrids in the matrix lattice and the metal undergoes degradation of its mechanical properties. Many studies have shown that defects in metals trap light gas atoms like H or He which are solved or implanted in the sample. Therefore, the decoration of defects with these atoms is a method to trace defect concentrations and to study the trapping and detrapping mechanism. Mobile defects can be trapped at implanted atoms, at inhomogeneities or at inner surfaces like grain boundaries or interfaces of different phases. Using the slow positron beam technique the traps for hydrogen attributed to vacancy-type defects have been investigated in cp-Ti implanted with nitrogen or carbon.The concentration of hydrogen has been detected by the 15N profiling technique (1H(15N,αγ)12C). The nitrogen and carbon content were measured by 15N(1H,αγ)12C and 13C(p,γ)14N reaction, respectively.

scholarly journals Mathematical Model For Forwarding Packets In Communication Network

2021 ◽  
Author(s):  
Samaa Adel Ibrahim Hussein ◽  
Fayez Wanis Zaki ◽  
Mohammed Ashour
Keyword(s):  
Data Transfer ◽  
Solution Procedure ◽  
Area Network ◽  
Wide Area Network ◽  
Phase Type Distribution ◽  
Application Performance ◽  
Phase Type ◽  
The Matrix ◽  
Matrix Geometric Solution ◽  
System States

Abstract In recent years, SDN technology has been applied to several networks such as wide area network (WAN). IT provides many benefits, such as: enhancing data transfer, promoting Application performance and reducing deployment costs. Software Defined-WAN networks lack studies and references. This paper introduced a system for SD-WAN network using PH/PH/C queues. It concentrates on the study of algebraic estimates the probability distribution of the system states. The Matrix-Geometric solution procedure of a phase type distribution queue with first-come first-served discipline is used.

scholarly journals On the effect of coalescence on the rheology of emulsions

2019 ◽  
Vol 880 ◽  
pp. 969-991 ◽  
Author(s):  
Francesco De Vita ◽  
Marco Edoardo Rosti ◽  
Sergio Caserta ◽  
Luca Brandt
Keyword(s):  
Disperse Phase ◽  
Effective Viscosity ◽  
Volume Fraction ◽  
Numerical Study ◽  
Extensional Flow ◽  
Interface Tension ◽  
Flow Topology ◽  
Volume Fractions ◽  
Rotational Components ◽  
The Matrix

We present a numerical study of the rheology of a two-fluid emulsion in dilute and semidilute conditions. The analysis is performed for different capillary numbers, volume fractions and viscosity ratios under the assumption of negligible inertia and zero buoyancy force. The effective viscosity of the system increases for low values of the volume fraction and decreases for higher values, with a maximum for approximately 20 % concentration of the disperse phase. When the dispersed fluid has lower viscosity, the normalised effective viscosity becomes smaller than 1 for high enough volume fractions. To single out the effect of droplet coalescence on the rheology of the emulsion we introduce an Eulerian force which prevents merging, effectively modelling the presence of surfactants in the system. When the coalescence is inhibited the effective viscosity is always greater than 1 and the curvature of the function representing the emulsion effective viscosity versus the volume fraction becomes positive, resembling the behaviour of suspensions of deformable particles. The reduction of the effective viscosity in the presence of coalescence is associated with the reduction of the total surface of the disperse phase when the droplets merge, which leads to a reduction of the interface tension contribution to the total shear stress. The probability density function of the flow topology parameter shows that the flow is mostly a shear flow in the matrix phase, with regions of extensional flow when the coalescence is prohibited. The flow in the disperse phase, instead, always shows rotational components. The first normal stress difference is positive, except for the smallest viscosity ratio considered, whereas the second normal difference is negative, with their ratio being constant with the volume fraction. Our results clearly show that the coalescence efficiency strongly affects the system rheology and that neglecting droplet merging can lead to erroneous predictions.

Effects of preparation methods on the mechanical and thermal properties of graphene-modified HNBR composites

e-Polymers ◽  
2018 ◽  
Vol 18 (1) ◽  
pp. 57-65 ◽  
Author(s):  
Dejiang Yang ◽  
Chun Wei ◽  
Yongyang Gong ◽  
Tianxi Liu ◽  
Jian Lv
Keyword(s):  
Mechanical And Thermal Properties ◽  
Butadiene Rubber ◽  
Mechanical Mixing ◽  
Graphene Nanosheet ◽  
Preparation Methods ◽  
Reinforcing Effect ◽  
Final Performance ◽  
Matrix Properties ◽  
The Matrix ◽  
Mixing Method

AbstractPolymers modified by graphene have become an attractive method to enhance the matrix properties, wherein the dispersion of graphene in the matrix and the interfacial interactions between graphene and matrix are critical to influence the final performance. In the present work, graphene nanosheet (GNS)-modified hydrogenated nitrile butadiene rubber (GNS/HNBR) composites were prepared via solution-mixing and mechanical-blending methods. The curing performance, mechanical properties and heat resistance of the prepared composites were studied. The results showed that when the content was 0.2 wt%, the tensile strength and modulus at 300% elongation of the GNS/HNBR composite prepared via solution-mixing method reached 19.36 and 3.62 MPa, which increased by 32% and 18% compared with those of pure HNBR, respectively. In addition, the swelling index of the composite in cyclohexane was decreased from 413% to 337%. On the other hand, the tensile property of GNS/HNBR composite prepared by mechanical-mixing method became poor. SEM observation showed that GNS was well dispersed and incorporated into HNBR via the solution-mixing method, resulting in a significant reinforcing effect.

Effect of Element V on the Microstructure and Mechanical Properties of DZ417G Superalloy

2014 ◽  
Vol 788 ◽  
pp. 446-451
Author(s):  
Zhao Xu Zhong ◽  
Xing Fu Yu ◽  
Ai Hua Huang ◽  
Yu Fei Wang ◽  
Yan Lin Man ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Temperature ◽  
Rupture Life ◽  
Creep Rupture ◽  
Block Type ◽  
Plastic Properties ◽  
Dispersion Degree ◽  
The Matrix ◽  
Life Tests

The effect of V content on the mechanical properties and microstructure of DZ417G alloy was studied in the present investigation. DZ417G alloy with different element V contents was smelted , then tested the mechanical properties and observed microstructure. The results show that with the increase of element V content, the morphology of rod type M23C6 carbides turned into block-type MC carbides, the size of carbides became bigger, and the amount of carbides decrased, but the dispersion degree of carbide in the matrix was increased. The alloy tensile strength and plastic properties were increased at high temperature with the increment of V content. There were finer dimple structures on the tensile rupture fracture surface of the alloy with high element V than the alloy with low element V under the high temperature conditions. The results of creep rupture life tests show that with increasing V content the creep rupture life increased at the test condition of 760 °C, 725MPa. The creep rupture life is 90h of the alloy with 0.62% V element content, and the creep rupture life increased to more than 245h when the element V content increased to 0.96%.

Optimization of repairable systems with repairman’s multiple vacations

2018 ◽  
Vol 35 (1) ◽  
pp. 266-290 ◽  
Author(s):  
Sarada Yedida ◽  
Shenbagam R.
Keyword(s):  
Renewal Process ◽  
Replacement Policy ◽  
Analytic Method ◽  
Repairable Systems ◽  
Maintenance Policy ◽  
Content Type ◽  
Matrix Analytic Method ◽  
Multiple Vacation ◽  
Phase Type ◽  
The Matrix

Purpose Technological advancements and growing complexity of many real-time systems, namely, communication, transportation, defense systems, etc., necessitate the importance to adopt a well-planned repair process such as phase type quasi-renewal process contributing to an improved system performance. Further, in an attempt to boost the role of maintenance as a financial benefactor, repairman’s multiple vacation policy is incorporated. Also, the significance of the degree of repair is illustrated while indicating the suitability of the matrix-analytic approach via the phase type quasi-renewal operating/repair times in reliability. The paper aims to discuss these issues. Design/methodology/approach The optimal replacement policy is obtained by employing the matrix-analytic method and minimum average cost rate. Findings The considered models make a significant contribution towards establishing that the matrix-analytic method, using the phase type quasi-renewal process, aids in reducing the computations and also fills the gap in the literature in the study of deteriorating systems. Availability and rate of occurrence of failures are evaluated in transient and steady-state regime. Originality/value This model differs from the existing models, in that, a repairman’s multiple vacation, delayed repair time and representation of the failure occurrence by a mixed Poisson process have been incorporated into the analysis. Also, time-dependent case and N-policy have been adopted to explore the optimality issues using phase type quasi-renewal process analytically. The numerical illustrations warrant that the maintenance policy proposed in this paper produces a considerably lower cost.

Sign in / Sign up

Export Citation Format

Share Document