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

The thermal and rheological properties of two types of metallocene-catalyzed linear low-density PEs (mLLDPEs) and two LDPEs, as well as their blends, were studied using differential scanning calorimeter (DSC) measurements and rheometry. The DSC results showed that the mLLDPE-1 based on the hexene comonomer is immiscible with both LDPEs in crystalline states, whereas the mLLDPE-2 based on the octene comonomer is miscible with the LDPEs. This suggests that increasing the length of short chains in mLLDPEs can promote the miscibility of mLLDPE/LDPE blends. The linear viscoelastic properties confirmed the immiscibility of the mLLDPE-1 with the LDPEs in the molten state, and the miscibility of mLLDPE-2 with LDPEs. In addition, the Palierne [1] emulsion model provided good predictions of the linear viscoelastic data for both miscible and immiscible PE blends. However, as expected, the low-frequency data showed a clear influence of the interfacial tension on the elastic modulus of the blends for the immiscible blends. POLYM. ENG. SCI., 45:1254–1264, 2005. © 2005 Society of Plastics Engineers

Thermal and rheological properties of mLLDPE/LDPE blends

The cell structure and properties of branched and linear polypropylene (PP) foams containing organically modified nanoclay and maleic anhydride grafted polypropylene (PPMA) have been thoroughly investigated. X-ray diffraction (XRD) and melt rheometry were used to identify the structure and linear viscoelastic properties of the nanocomposites, as well as the effectiveness of two different compatibilizers. These nanocomposites were used in injection molding to investigate their foamability and the influence of experimental conditions such as chemical foaming agent concentration, shot size, back pressure, injection speed, as well as melt temperature and different injection methods on the resulting cell structure of the foams. Quite different results were obtained with the linear and the branched PP. While the foamability of the branched PP was intrinsically good, that of the linear one could largely be improved by modifying its rheological properties and favoring nucleation through the addition of nanoclay. The effect of cell structure on the dynamic mechanical properties of the foams was also investigated using dynamic mechanical analysis (DMA). POLYM. ENG. SCI., 47:1070–1081, 2007. © 2007 Society of Plastics Engineers

Cell structure and dynamic properties of injection molded polypropylene foams

Dynamic perturbations and off-centered single and dual mixing impeller configurations have been investigated to reduce mixing time with viscous fluids. Mixing times, measured with a color-discoloration technique based on a fast acid-base reaction, reveal the presence of both segregated and dead zones. A statistical design approach has been used to evaluate the effect of the impeller position as well as the dynamic conditions. Homogenization is significantly enhanced when a radial flow impeller is used under both off-centered and dynamic perturbation conditions. In the case of an axial flow impeller, a combination of long clockwise times and short counter-clockwise times give better mixing times. An enhanced homogenization is also observed when a dual impeller configuration is used.



Des perturbations dynamiques et differentes configurations d'agitateurs de centres ont ete etudiees pour reduire le temps de melange de fluides visqueux. Les temps de melange ont ete mesures avec une technique de coloration-decoloration. Cette technique permet d'identifier aussi la presence de compartiments et de zones mortes. Un plan d'experiences statistique a ete concu pour evaluer l'influence de la position de l'agitateur ainsi que l'effet des conditions dynamiques sur le temps de melange. L'homogeneisation a ete sensiblement augmentee quand une turbine a ecoulement radial est utilisee en configuration decentree ou en mode dynamique perturbe. Dans le cas d'une turbine axiale, une combinaison d'un temps d'agitation court dans le sens horaire et d'un temps d'agitation long dans le sens anti-horaire a permis d'obtenir les temps de melange les plus courts. On obtient egalement un meilleur melange pour la configuration basee sur un double agitateur decentree.

Unconventional Configuration Studies to Improve Mixing Times in Stirred Tanks

Structure and properties of MDO stretched polypropylene

Bubble instabilities observed in film blowing using four different polyolefins are discussed: high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and polypropylene (PP). Special attention is given to the effect of the frost line height on the bubble stability, an effect mostly ignored in the literature. A video-camera system was used to record the bubble shape and oscillations. In general, three forms of instabilities and combinations were observed: (1) axisymmetric periodic variations in the bubble diameter; (2) helical motions of the bubble; and (3) variations in the position of the solidification line. The four resins show different stability behaviors. The LDPE has the most stable operating space and the PP is the most unstable one. No correlation was observed between bubble stability and oscillatory shear rheological properties of the resins. Instability is enhanced by increasing take-up ratio, increasing blow-up ratio, and decreasing frost line height. Furthermore, for the LDPE, some operating points were not attainable and multiple steady states were observed. Our results are in a poor agreement with the predictions Cain and Denn's 1988 analysis.

Pierre J. Carreau

Papers

Thermal and rheological properties of mLLDPE/LDPE blends

Cell structure and dynamic properties of injection molded polypropylene foams

Unconventional Configuration Studies to Improve Mixing Times in Stirred Tanks

Structure and properties of MDO stretched polypropylene

Study of instabilities in film blowing