Temperature sensor tag based on supercavity mode of dielectric resonator

This paper presents a wireless temperature sensor design based on the excitation of a high-Q supercavity mode in a dielectric resonator. Narrow resonance bandwidth improves sensor performance enabling accurate temperature measurements. The sensor consists of a half split ceramic cylinder attached to a metal sheet. The resonator parameters which lead to the excitation of a supercavity mode were obtained numerically. When the ambient temperature increased continuously from 23 to 120°C the notable shift of the resonant frequency was experimentally demonstrated.

Power output enhancement in ceramic, mL-scale Microbial Fuel Cell

<p>A microbial fuel cell (MFC) is a renewable energy converter, which transforms organic biomass directly into electricity, using biofilm-electrode metabolic interaction within a bioelectrochemical cell. Efficiency of this transformation can be enhanced through miniaturisation. Miniaturisation of MFCs offers higher surface-area-to-volume ratio and improved mass transfer.</p> <p>The development of mL-scale; power dense and low cost MFCs, are of great interest in diverse areas of research, ranging from modern bio-robotics, internet-of-things devices, electrical energy generation, remote sensing to wastewater treatment and mineral recovery. The biofilms increased ability in converting organic pollutants into electric power more efficiently, makes mL-sized MFCs attractive for the development of multi-modular stacks and usable off-grid power sources with an ability of enhanced wastewater treatment. This work focuses on small scale MFCs; i) minimising the distance between feeding stream and the biofilm, ii) construction and analysis of a  millilitre scale prototype, using a low cost ceramic separator for higher energy recovery efficiency and sensitivity enhancement to substrates and pollutants. The study aims to test efficient cathode modifications, using graphene ink and magnetite (Fe<sub>3</sub>O<sub>4</sub>); in order to improve the oxygen reduction reaction (ORR). This in turn is envisioned in an increase of the output, reaching comparable power levels to the larger MFC prototypes tested so far. The additives are chosen such that,  both graphene and iron–based oxides are known from the literature to be catalysts for electrochemical processes, this work focusses on their incorporation into the open-to air cathode in novel, low cost MFC bioreactors.</p> <p>The miniaturised MFC construction constituted of an in-house fabricated small scale ceramic cylinder of internal volume of 3.88 mL. An anode, made of carbon veil fibre with a coating of activated carbon powder, was placed inside the ceramic cylinder, while the cathode was attached to the outer surface of the structure. Three types of cathodes were tested: i) activated carbon as the control (AC), ii) AC with a graphene ink coating (AC+G) and iii) AC with graphene ink and magnetite powder blend (AC+G+M). Experiments were conducted in triplicate using activated sludge and urine inoculum and thereafter continuously supplemented with 100% real human urine. The results show that the control produced up to 0.85 mW (219 W/m<sup>3</sup>), while AC+G produced 1.22 mW (312 W/m<sup>3</sup>), and AC+G+M 1.12 (288 W/m<sup>3</sup>) which is a 44 % and a 32 % increase respectively in comparison to the control. Comparison of linear sweep voltammetry (LSV) showed superior performance of both modified electrodes against the unmodified AC cathode; further resulting in an enhancement of ORR reaction rate. Power outputs from this work show over 14 times improvement in power density levels in comparison to larger reactors of 20 times the volume, as well as comparable raw (actual) power levels. This makes these novel small-scale bioreactors particularly attractive for use in numerous practical applications such as energy autonomous robots (e.g. EcoBots) and multi-modular stacks for off-grid energy sources.</p> <p> </p>

Experimental Study on the Influence of Ceramist Properties Compressive Strength of Shale Ceramist Concrete

There are 6 group of experimental research to explore the relationship between shale ceramist concrete compressive strength and ceramic cylinder compressive strength, particle size, absorption time. The result shows that the strength of shale ceramist concrete is not only relevant with the ceramic cylinder compressive strength, but also relevant with the aggregate size, absorption time. For single graded particle size concrete, the strength of concrete decreased with grain size increasing. The longer time of ceramic absorption, the more sufficient the ceramist concrete strength development.

A piezoelectric energy harvester based on flow-induced flexural vibration of a circular cylinder

This article proposes a new piezoelectric structure for energy harvesting from flow-induced vibrations. It consists of a properly poled and electroded flexible ceramic cylinder. When it is in a flow perpendicular to its axis, the flow exerts a transverse force on the cylinder due to asymmetric vortex shedding, which drives the cylinder into flexural vibrations with an electrical output. A one-dimensional model is derived for the motion of the cylinder, which allows an analytical solution from which the basic behaviors of the energy harvester are calculated and examined. For a cylinder of 40 cm in length and [Formula: see text]cm in diameter in flowing air with a speed of 5 m/s, the output power is of the order of [Formula: see text]. It becomes significantly higher if the flow speed is increased.

A 300 kHz High-Frequency Underwater Transducer

A new type of piezoelectric composite ultrasonic transducer with high frequency in radial vibration is studied. A high-frequency acoustic transducer has been designed and prepared with pzt-5-type piezoelectric ceramic cylinder. When the piezoelectric ceramic cylinder vibrates along the direction of its radial direction, the working frequency is high. It is composed of a piezoelectric ceramic tube and a steel bracket which is inserted in the inner of the ceramic tube. Use the finite element method by ANSYS for analyzing the radial vibration of a piezoelectric tube. On that basis, through managing ANSYS simulation the vibration mode of transducer system is obtained, and analyzed the working frequency of transducer. According to the simulation, the high-frequency cylindrical acoustic transducer has been produced. Comparing the products and the traditional cylindrical transducers, the products haven’t only a good all-round circle directional, but it also has a high working frequency (300 kHz).