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

Electroactive phases of poly(vinylidene fluoride) : determination, processing and applications

Shape-memory polymers (SMPs) have attracted significant attention from both industrial and academic researchers due to their useful and fascinating functionality. This review thoroughly examines progress in shape-memory polymers, including the very recent past, achieved by numerous groups around the world and our own research group. Considering all of the shape-memory polymers reviewed, we identify a classification scheme wherein nearly all SMPs may be associated with one of four classes in accordance with their shape fixing and recovering mechanisms and as dictated by macromolecular details. We discuss how the described shape-memory polymers show great potential for diverse applications, including in the medical arena, sensors, and actuators.

http://research.vuse.vanderbilt.edu/srdesign/2009/group8/Papers/shape%20memory%20polymers%20review%20article.pdf

Review of progress in shape-memory polymers

Fundamentals, processes and applications of high-permittivity polymer–matrix composites

A number of materials have been explored for their use as artificial muscles Among these, dielectric elastomers (DEs) appear to provide the best combination of properties for true muscle-like actuation DEs behave as compliant capacitors, expanding in area and shrinking in thickness when a voltage is applied Materials combining very high energy densities, strains, and efficiencies have been known for some time To date, however, the widespread adoption of DEs has been hindered by premature breakdown and the requirement for high voltages and bulky support frames Recent advances seem poised to remove these restrictions and allow for the production of highly reliable, high-performance transducers for artificial muscle applications

Advances in dielectric elastomers for actuators and artificial muscles.

Micromachined unimorph actuators based on the electrostrictive P(VDF-TrFE) copolymer have been fabricated. The performance of the devices has been modeled and characterized. The experimental results on the device responses are very close to the prediction of the model, indicating a high actuator displacement and voltage sensitivity. For a typical unimorph device with 1 mm length, the displacement at the center of the device can reach 30 micrometers , and the ratio of the displacement/applied voltage is more than 30nm/V. Furthermore, over more than 3 frequency decades, the dispersion of the displacement is less than 20%, which indicates the high frequency capability of this polymer based MEMS. To demonstrate the high force capability of the device, the displacement response of the device was evaluated at 200 Hz ina fluid medium and there is no observable change in the displacement response in fluid medium when compared with that measured in air. Due to the large field induced electrostrictive strain and high frequency capability of the electrostrictive P(VDF-TfFE), the device is capable of operating at no-resonance model with high displacement and force output, and over a broad frequency range (DC to >10 kHz). The observed performance of the device indicates that this type of electrostrictive P(VDF-TrFE) based MEMS is attractive for micro-pump, values, and air coupled ultrasonic transducer array, etc.

Electrostricitive P(VDF-TrFE) copolymer-based high-performance micromachined unimorph actuators

In many device applications, such as electro-acoustic transducers and actuators based on high strain electroactive polymers, there are many advantages to utilize conductive polymers as electrodes. However, in these applications, a high electric power usually is required which translates to high voltage and high current in the system. Hence, the maximum current density which a conducting polymer can carry is of great interest and importance. In this paper, the conduction behavior at high current density of doped polyaniline(PANI) is reported. It was found that the current density deviates strongly from the ohmic relation with the electric field in high current density region and a saturation of the current density was observed. The maximum current density J m observed is proportional to the conductivity of the samples and for PANI doped with HCSA, J m can reach as high as 1200 A/cm 2 . Making use of the conducting polymer as the electrodes for the electrostrictive P(VDF-TrFE) copolymer, an all-polymer electromechanical system was fabricated. The all-polymer films exhibit similar or larger electric field induced strain responses than those from films with gold electrodes, presumably due to reduced mechanical clamping from the electrodes. In addition, the all-polymer system also exhibits comparable dielectric and polarization properties to those of gold-electroded P(VDF-TrFE) films in a wide temperature (from −50°C to 120°C) and frequency range (from 1Hz to 1MHz). These results demonstrate that polyaniline can be used for many electro-acoustic devices and provide improved performance.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S194642740020523X

Conduction behavior of doped polyaniline under high current density and the performance of an all polymer electromechanical system

Influence of protective layer thinning on the electrocaloric performance of 0.8Ba(Ti0.82Zr0.18)O3–0.2Ba(Ti0.9Sn0.1)O3 multilayer ceramic films

Ferroelectric polymer thin films are attractive for a wide range of applications such as MEMS, IR sensors, and memory devices. We present the results of a recent investigation on the thickness dependence of the ferroelectric properties of poly(vinylidene fluoridetrifluoroethylene) copolymer spin cast films on electroded Si substrate. We show that as the film thickness is reduced, there exist two thickness regions. For films at thickness above 100 nm, the thickness dependence of the ferroelectric properties can be attributed to the interface effect. However, for thinner films, there is a large change in the ferroelectric properties such as the polarization level, the coercive field, and polarization switching speed, which is related to the large drop of the crystallinity in the ultrathin film region (below 100 nm). The results from Xray, dielectric measurement, and AFM all indicate that there is a threshold thickness at about 100 nm below which the crystallinity in the film reduces abruptly.

Haisheng Xu

Papers

Electrostricitive P(VDF-TrFE) copolymer-based high-performance micromachined unimorph actuators

Conduction behavior of doped polyaniline under high current density and the performance of an all polymer electromechanical system

Influence of protective layer thinning on the electrocaloric performance of 0.8Ba(Ti0.82Zr0.18)O3–0.2Ba(Ti0.9Sn0.1)O3 multilayer ceramic films

Effect of interface and crystallinity on the ferroelectric properties of poly(vinylidene fluoride-trifluoroethylene) copolymer thin films