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

In this work, a chain extender (CE) was added to polylactide (PLA) to improve its foamability. The steady and transient rheological properties of neat PLA and CE-treated PLA revealed that the introduction of the CE profoundly affected the melt viscosity and elasticity. The linear viscoelastic properties of CE-enriched PLA suggested that a long-chain branching (LCB) structure was formed from the reaction with the CE. LCB-PLA exhibited an increased viscosity, more shear sensitivity, and longer relaxation time in comparison with the linear PLA. The LCB structure was also found to affect the transient shear stress growth and elongational flow behavior. LCB-PLA exhibited a pronounced strain hardening, whereas no strain hardening was observed for the linear PLA. Batch foaming of the linear and LCB-PLAs was also examined at foaming temperatures of 130, 140, and 155 °C. The LCB structure significantly increased the integrity of the cells, cell density, and void fraction.

Rheological and foaming behavior of linear and branched polylactides

In order for sustainable nanomaterials such as cellulose nanocrystals (CNCs) to be utilized in industrial applications, a large-scale production capacity for CNCs must exist. Currently the only CNCs available commercially in kilogram scale are obtained from wood pulp (W-CNCs). Scaling the production capacity of W-CNCs isolation has led to their use in broader applications and captured the interest of researchers, industries and governments alike. Another source of CNCs with potential for commercial scale production are tunicates, a species of marine animal. Tunicate derived CNCs (T-CNCs) are a high aspect ratio CNC, which can complement commercially available W-CNCs in the growing global CNC market. Herein we report the isolation and characterization of T-CNCs from the tunicate Styela clava, an invasive species currently causing significant harm to local aquaculture communities. The reported procedure utilizes scalable CNC processing techniques and is based on our experiences from laboratory scale T-CNC isolation and pilot scale W-CNC isolation. To our best knowledge, this study represents the largest scale where T-CNCs have been isolated from any tunicate species, under any reaction conditions. Demonstrating a significant step towards commercial scale isolation of T-CNCs, and offering a potential solution to the numerous challenges which invasive tunicates pose to global aquaculture communities.

/pdf/towards-the-scalable-isolation-of-cellulose-nanocrystals-4hxzt8zif8.pdf

Towards the scalable isolation of cellulose nanocrystals from tunicates.

The linear viscoelastic behavior of starches from various origins, blended with different amounts of a plasticizer using a twin screw extruder, has been investigated. Conditions of stability for reliable measurements and linearity domain have been determined. At low strain, the plasticized starch is found to behave as a viscoelastic gel-like material. This behavior is partially explained by its semicrystalline structure, as evidenced by x-ray diffraction patterns. Crystallites are assumed to participate in the formation of an elastic network, embedded in a viscoelastic amorphous phase. Additional thermomechanical treatment reduces crystallinity and leads to a decrease of the storage and loss moduli. The plasticizing role of water is found to be important. The higher molecular weight of the potato starch is responsible for its larger moduli. In the case of maize starch, the highly branched amorphous amylopectin softens the structured behavior, resulting in lower moduli compared to those of rich-content amy...

Relationship between structure and viscoelastic behavior of plasticized starch

Batch mixing of viscous fluids with helical-ribbon agitators in 2.4 liter and 13 liter vessels has been studied for agitator speeds up to 200 RPM. Seven different agitators of different dimensions were employed in this work. Mixing times were measured using a decoloration technique and circulation times were determined by the tracer bead method. In addition, velocity profiles were obtained from streak photographs using selective illumination of the vessel and PVC powder as tracer particles.



It was found that the mixing times of Newtonian fluids, which agreed with previously published data, were considerably (3 to 7 times) shorter than those of the viscoelastic fluids. The mixing time was strongly affected by the fluids' elasticity; increasing as the fluid elasticity increased. The velocity profiles were qualitatively similar for all the fluids but showed decreased axial circulation and increased circumferential flow as fluid elasticity increased. However, mixing is not only a function of the axial circulation (impeller pumping rate) but also is a function of the perturbations superimposed on the main flow. A simple, first approximation model based on the impeller geometry and flow patterns is proposed to correlate the circulation capacity and mixing time data for the various geometries studied.



On a etudie, en employant des vitesses d'agitation atteignant 200 tours a la minute, le melange discontinu de fluides visqueux assure par des agitateurs a ruban helicoidal dans des vaisseaux de 2.4 litres et 13 litres; on a utilise a cette fin sept agitateurs differents de dimensions variees. On a mesure les temps de melange par une methode de decoloration et determine les temps de circulation au moyen d'une methode a base de perles marquees. On a, en outre, obtenu des profils de vitesse a partir de photographies avec stries, en utilisant un eclairage selectif du vaisseau et de la poudre de chlorure de polyvinyle qui servait pour les particules marquees.



On a trouve que les temps de melange des fluides newtoniens, qui correspondaient a ceux qui ont deja ete publies, etaient bien plus faibles (3 a 7 fois) que les temps de melange des fluides visco-elastiques. L'elasticite des fluides a considerablement affecte le temps de melange, qui augmentait avec celleci. Les profils de vitesse se sont averes qualitativement semblables pour tous les fluides, mais ils ont indique une circulation axiale moindre et un ecoulement circonferentiel accru, a mesure que l'elasticite des fluides augmentait. Toutefois, le melange est une fonction non seulement de la circulation axiale, (taux de pompage du rotor), mais aussi des perturbations sur-imposees sur l'ecoulement principal. On propose un modele simple et fournissant une premiere approximation, lequel est base sur la geometrie du rotor et les types d'ecoulement, en vue d'etablir des correlations entre les resultats relatifs a la circulation et aux temps de melange, dans le cas des diverses formes geometriques etudiees.

Pierre J. Carreau

Papers

Rheological and foaming behavior of linear and branched polylactides

Towards the scalable isolation of cellulose nanocrystals from tunicates.

Relationship between structure and viscoelastic behavior of plasticized starch

Mixing of viscoelastic fluids with helical-ribbon agitators. I — Mixing time and flow patterns

Chitosan and glycerophosphate concentration dependence of solution behaviour and gel point using small amplitude oscillatory rheometry