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

The investigation of the conversion of vibrational energy into electrical power has become a major field of research. In recent years, bistable energy harvesting devices have attracted significant attention due to some of their unique features. Through a snap-through action, bistable systems transition from one stable state to the other, which could cause large amplitude motion and dramatically increase power generation. Due to their nonlinear characteristics, such devices may be effective across a broad-frequency bandwidth. Consequently, a rapid engagement of research has been undertaken to understand bistable electromechanical dynamics and to utilize the insight for the development of improved designs. This paper reviews, consolidates, and reports on the major efforts and findings documented in the literature. A common analytical framework for bistable electromechanical dynamics is presented, the principal results are provided, the wide variety of bistable energy harvesters are described, and some remaining challenges and proposed solutions are summarized.

https://iopscience.iop.org/article/10.1088/0964-1726/22/2/023001/pdf

A review of the recent research on vibration energy harvesting via bistable systems

Ambient energy harvesting has been in recent years the recurring object of a number of research efforts aimed at providing an autonomous solution to the powering of small-scale electronic mobile devices. Among the different solutions, vibration energy harvesting has played a major role due to the almost universal presence of mechanical vibrations. Here we propose a new method based on the exploitation of the dynamical features of stochastic nonlinear oscillators. Such a method is shown to outperform standard linear oscillators and to overcome some of the most severe limitations of present approaches. We demonstrate the superior performances of this method by applying it to piezoelectric energy harvesting from ambient vibration.

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Nonlinear energy harvesting.

This paper reviews energy harvesting technology from mechanical vibration. Recent advances on ultralow power portable electronic devices and wireless sensor network require limitless battery life for better performance. People searched for permanent portable power sources for advanced electronic devices. Energy is everywhere around us and the most important part in energy harvesting is energy transducer. Piezoelectric materials have high energy conversion ability from mechanical vibration. A great amount of researches have been conducted to develop simple and efficient energy harvesting devices from vibration by using piezoelectric materials. Representative piezoelectric materials can be categorized into piezoceramics and piezopolymers. This paper reviews key ideas and performances of the reported piezoelectric energy harvesting from vibration. Various types of vibration devices, piezoelectric materials and mathematical modeling of vibrational energy harvestings are reviewed.

A Review of Piezoelectric Energy Harvesting Based on Vibration

This review provides a detailed overview of the energy harvesting technologies associated with piezoelectric materials along with the closely related sub-classes of pyroelectrics and ferroelectrics. These properties are, in many cases, present in the same material, providing the intriguing prospect of a material that can harvest energy from multiple sources including vibration, thermal fluctuations and light. Piezoelectric materials are initially discussed in the context of harvesting mechanical energy from vibrations using inertial energy harvesting, which relies on the resistance of a mass to acceleration, and kinematic energy harvesting which directly couples the energy harvester to the relative movement of different parts of a source. Issues related to mode of operation, loss mechanisms and using non-linearity to enhance the operating frequency range are described along with the potential materials that could be employed for harvesting vibrations at elevated temperatures. In addition to inorganic piezoelectric materials, compliant piezoelectric materials are also discussed. Piezoelectric energy harvesting devices are complex multi-physics systems requiring advanced methodologies to maximise their performance. The research effort to develop optimisation methods for complex piezoelectric energy harvesters is then reviewed. The use of ferroelectric or multi-ferroic materials to convert light into chemical or electrical energy is then described in applications where the internal electric field can prevent electron–hole recombination or enhance chemical reactions at the ferroelectric surface. Finally, pyroelectric harvesting generates power from temperature fluctuations and this review covers the modes of pyroelectric harvesting such as simple resistive loading and Olsen cycles. Nano-scale pyroelectric systems and novel micro-electro-mechanical-systems designed to increase the operating frequency are discussed.

/pdf/piezoelectric-and-ferroelectric-materials-and-structures-for-39myuuqvo7.pdf

Piezoelectric and ferroelectric materials and structures for energy harvesting applications

We present comprehensive experimental and theoretical work on tunnel-barrier rectifiers comprising bilayer (Nb2O5/Al2O3) insulator configurations with similar (Nb/Nb) and dissimilar (Nb/Ag) metal electrodes. The electron affinity, valence band offset, and metal work function were ascertained by X-ray photoelectron spectroscopy, variable angle spectroscopic ellipsometry, and electrical measurements on fabricated reference structures. The experimental band line-up parameters were fed into a theoretical model to predict available bound states in the Nb2O5/Al2O3 quantum well and generate tunneling probability and transmittance curves under applied bias. The onset of strong resonance in the sub-V regime was found to be controlled by a work function difference of Nb/Ag electrodes in agreement with the experimental band alignment and theoretical model. A superior low-bias asymmetry of 35 at 0.1 V and a responsivity of 5 A/W at 0.25 V were observed for the Nb/4 nm Nb2O5/1 nm Al2O3/Ag structure, sufficient to achieve a rectification of over 90% of the input alternate current terahertz signal in a rectenna device.

/pdf/controlled-modification-of-resonant-tunneling-in-metal-3yxe171z2n.pdf

Controlled modification of resonant tunneling in metal-insulator-insulator-metal structures

Purpose – The purpose of this paper is to demonstrate the feasibility of using kinetic energy harvesting to power wireless condition monitoring sensors. Design/methodology/approach – The system presented duty cycles its operation depending upon the energy being harvested. The harvested energy is stored on a supercapacitor and the system samples sufficient vibration data to enable an FFT to be performed at the receiver. Findings – The results of this study show it is perfectly feasible to power practical wireless condition monitoring sensors entirely from the vibrations of the machines being monitored. Originality/value – Energy harvesting techniques can be used to power wireless sensors in a range of applications. Removing the need for a battery power supply presents obvious environmental benefits and avoids the need to periodically replace batteries.

Self powered wireless sensors for condition monitoring applications

This paper describes the design and fabrication of a screen printed network of bio-potential measurement electrodes on a garment, in this case a vest. The electrodes are placed according to the Frank configuration, which allows monitoring of the electrical behavior of the heart in three spatial orientations. The vest is designed to provide stable contact pressure on the electrodes. The electrodes are fabricated from stencil printed carbon loaded rubber and are connected by screen printed silver polymer conductive tracks to an array of vias, which form an electrical connection to the other side of the textile. The vest is tested and compared to Frank configuration recordings that were obtained using standard self-adhesive ECG electrodes. The vest was successfully used to obtain Frank configuration recordings with minimal baseline drift. The vest is fabricated using only technologies found in standard textile production lines and can be used with a reduced setup effort compared to clinical 12-lead examinations.

/pdf/a-printed-dry-electrode-frank-configuration-vest-for-iicscu5oi4.pdf

A printed, dry electrode Frank configuration vest for ambulatory vectorcardiographic monitoring

Dataset supports:
Komolafe, A., Torah, R. N., Tudor, J., & Beeby, S. P. (2018). Modelling and experimental validation of the effect of the elastic properties of fabrics on the durability of screen printed e-textiles. Smart Materials and Structures.The effect of the differing elastic properties of fabrics on the durability of electronics integrated in or on the fabric is still largely unknown because fabric properties are not easily characterized. Using a mathematical model combining classical beam theory (CBT) and Pierce’s fabric cantilever test, this paper models the bending behaviour of a woven fabric and locates its neutral axis (NA) as a basis for developing more durable printed e-textiles.

/pdf/modelling-and-experimental-validation-of-the-effect-of-the-18z3qahmf8.pdf

Modelling and experimental validation of the effect of the elastic properties of fabrics on the durability of screen printed e-textiles

This paper presents a method to integrate and package an accelerometer within a textile to create an electronic textile (e-textile). The smallest commercially available accelerometer sensor (2 mm × 2 mm × 0.95 mm) is used in the e-textile and is fully integrated within the weave structure of the fabric itself, rendering it invisible to the wearer. The e-textile forms the basis of a wearable woven sleeve which is applied to arm and knee joint bending angle measurement. The integrated e-textile based accelerometer sensor system is used to identify activity type, such as walking or running, and count the total number of steps taken. Performance was verified by comparing measurements of specific elbow joint angles over the range of 0° to 180° with those obtained from a commercial bending sensor from Bend Labs and from a custom-built goniometer. The joint bending angles, measured by all three sensors, show good agreement with an error of less than ~1% of reading which provides a high degree of confidence in the e-textile sensor system. Subsequently, knee joint angles were measured experimentally on three subjects with each being tested three times on each of three activities (walking, running and climbing stairs). This allowed the minimum and maximum knee joint angles for each activity to be determined. This data is then used to identify activity type and perform step counting.

Stephen Beeby

Papers

Controlled modification of resonant tunneling in metal-insulator-insulator-metal structures

Self powered wireless sensors for condition monitoring applications

A printed, dry electrode Frank configuration vest for ambulatory vectorcardiographic monitoring

Modelling and experimental validation of the effect of the elastic properties of fabrics on the durability of screen printed e-textiles

Integration and Testing of a Three-Axis Accelerometer in a Woven E-Textile Sleeve for Wearable Movement Monitoring.