Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Chitin and chitosan: Properties and applications

Carbon nanotubes (CNTs) hold the promise of delivering exceptional mechanical properties and multi-functional characteristics. Ever-increasing interest in applying CNTs in many different fields has led to continued efforts to develop dispersion and functionalization techniques. To employ CNTs as effective reinforcement in polymer nanocomposites, proper dispersion and appropriate interfacial adhesion between the CNTs and polymer matrix have to be guaranteed. This paper reviews the current understanding of CNTs and CNT/polymer nanocomposites with two particular topics: (i) the principles and techniques for CNT dispersion and functionalization and (ii) the effects of CNT dispersion and functionalization on the properties of CNT/polymer nanocomposites. The fabrication techniques and potential applications of CNT/polymer nanocomposites are also highlighted.

Dispersion and functionalization of carbon nanotubes for polymer-based nanocomposites: a review

http://www.mtdna.or.kr/neowiz/board/up_files/files_17/Chitin_Chitosan_polymers_chemistrySolubilityFiberFormation.pdf

Chitin and chitosan polymers: Chemistry, solubility and fiber formation

Our aim is to propose a theory which goes beyond the classical formulation of thermodynamics. This is achieved by enlarging the space of basic independent variables, through the introduction of non-equilibrium variables, such as the dissipative fluxes appearing in the balance equations. The next step is to find evolution equations for the dissipative fluxes. Whereas the evolution equations for the classical variables are given by the usual balance laws, no general criteria exist concerning the evolution equations of the dissipative fluxes, with the exception of the restrictions imposed on them by the second law of thermodynamics.

https://iopscience.iop.org/article/10.1088/0034-4885/51/8/002/pdf

Extended irreversible thermodynamics

Extensional rheological properties play an important role in processes in which the fluid is subjected to highly decelerated or accelerated flows. This paper describes an orifice flowmeter used to measure extensional properties of rheologically complex fluids at high strain rates. The operating principle of the flowmeter is based on the pressure drop due to the flow through a small size orifice. The flowmeter was first calibrated, by plotting the pressure drop-flow rate curve of the orifice, in terms of a dimensionless Euler number versus Reynolds number. Newtonian fluids consisting of aqueous solutions of corn syrup were used as calibration fluids. The calibration curve was then used to determine the apparent extensional viscosity of three different paper coating colors. The apparent extensional viscosity is compared to the shear viscosity in terms of the Trouton ratio. The Trouton ratio for one coating color is shown to exceed considerably the theoretical value of 3 expected for Newtonian fluids.



Les proprietes rheologiques elongationnelles jouent un role important dans les processus dans lesquels le fluide est soumis a des decelerations ou accelerations rapides. Cet article decrit un rheometre a orifice utilise pour mesurer les proprietes elongationnelles de fluides rheologiquement complexes a des vitesses de deformation elevees. Le principe de fonctionnement du rheometre est base sur la chute de pression du fluide qui passe au travers d'un petit orifice. Le rheometre a ete initialement etalonne en tracant la courbe du nombre d'Euler en fonction du nombre de Reynolds pour des fluides newtoniens (solutions aqueuses du sirop de mais). La courbe d'etalonnage a ete alors employee pour determiner la viscosite elongationnelle de trois differentes sauces de couchage de papier. La viscosite elongationnelle est comparee a la viscosite de cisaillement en terme du rapport de Trouton. Le rapport de Trouton pour une sauce de couchage excede considerablement la valeur theorique de 3 qui devrait etre obtenue pour des fluides newtoniens.

Orifice flowmeter for measuring extensional rheological properties

In this study, the effects of machine direction orientation (MDO) conditions on crystalline orientation, morphology, and mechanical performance of a high-density polyethylene film were investigated. The MDO variables studied were feed speed, stretching temperature, draw ratio (DR) as well as annealing temperature. The type of crystals (spherulites or fibrils) and crystallinity of the films were considered using differential scanning calorimetry. The MDO process increased the film crystallinity by 18% and melting temperature (Tm ) by 5°C. The crystalline phase orientation was measured using Fourier transform infrared and wide angle X-ray diffraction. Stretching noticeably increased the crystalline alignment. The Young’s modulus decreased with increasing extrusion temperature and feed speed and enhanced with rising annealing temperature. However, up to DR = 6, the Young’s modulus decreased with draw ratio whereas it increased beyond DR = 6. Upon drawing, the tear resistance along the machine direction decre...

Effect of Machine Direction Orientation Conditions On Properties of Hdpe Films

Rheological Properties Of Concentrated Suspensions: Applications To Foodstuffs

A novel nonequilibrium molecular dynamics, originating in mesoscopic theory of suspensions, is introduced to investigate the behavior of model polymeric fluids consisting of several hundred ellipsoids of revolution (spheroids) that interact via the Gay-Berne potential. This dynamics is used to generate new microstructural, thermodynamic and rheological data. The microcanonical equtions of motion for the translational and angular momenta as well as for mass-centers and orientational unit vectors are derived from a Hamiltonian. These expresssions are then augmented by SLLOD-like and Gaussian thermostat terms added consistently to equations for both the rotational and translational degrees of freedom; the role of Gaussian thermostat is to maintain constant kinetic temperature of the assembly of spheroids. The thermodynamic results are calculated along one isotherm (nondimensional temperature T maintained at unity). Rheology is investigated for two state points (namely for particle number density p equal to 0.25, 0.4 and T set to 1), that lie well inside the isotropic phase if no external flow is applied. A state point is defined by the fluid's temperature T,. and the concentration of particles per unit volume p. As indicated by snapshots of molecular configurations, at the intermediate shear rates (nondimensional shear rate approximately 1–2), ellipsoids become aligned to the direction of flow and the stress tensor begins to be nonsymmetric. At even higher shear rates, this configuration breaks down leading to the formation of a transitory isotropic-type fluid, and then to the build-up of a highly ordered structure exhibiting global orientation of particles in the direction of the vorticity axis.

For ϱ = 0.4, the first (N1) and the second (N2) normal stress differences are positive and negative respectively, but at low densities (ϱ = 0.25), n1 becomes slightly negative. In addition to the stress tensor, we compute the conformation tensor, the order parameter and the components of the pair radial distribution function. At high shear rates the radial distribution functions become significantly anisotropic. Furthermore, we investigate the phenomenon of the stress overshoot at the inception of the simple shear flow from a molecular perspective, and study the evolution of the distribution of translational velocities as a function of the shear rate.

Rheology of several hundred rigid bodies

Die design is a daily concern in the manufacturing of extruded profiles. There are very few available Computer Aided Design (CAD) tools for profile die designers and considerable time and resources must be devoted to trial and error design procedures. This paper examines the applicability of the flow analysis network (FAN) to the design of profile extrusion dies. The FAN method is found to provide useful design information at a fraction of the computing cost required for 2.5 and 3D finite element methods. Experimental flow distribution obtained by extruding PVC compounds and polyethylene through simple profile dies are compared to model predictions. The numerical and experimental results provide evidence about the significant contribution of transverse flow to the flow distribution at die exit.

Pierre J. Carreau

Papers

Orifice flowmeter for measuring extensional rheological properties

Effect of Machine Direction Orientation Conditions On Properties of Hdpe Films

Rheological Properties Of Concentrated Suspensions: Applications To Foodstuffs

Rheology of several hundred rigid bodies

Evaluation of the FAN Technique for Profile Die Design