bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermally self-sustaining tubular SOFC power generator with no moving parts
Authors: Wongwiwat J , Bhuripanyo P , Welles T S , DeBiase V P , Ahn J , Ronney P D
Published: December 2019

Hydrocarbon fuels is roughly 50 times higher energy density compared to commercial batteries. However, scaling down electrical power generators for portable devices have been far from successful due to the difficulties of minimizing heat and friction losses. Hence, an alternate solution without moving parts incorporating a micro-tubular solid oxide fuel cell (mT-SOFC), thermal transpiration (gas pumping in a nanoporous medium from temperature gradient) and catalytic combustion on platinum surface is proposed. The concept involves having thermal transpiration membrane utilizes the temperature gradient created by mT-SOFC and catalytic combustion to supply reactants at high temperature to mT-SOFC for its operation. With this concept, catalytic combustion modeling and thermal transpiration membrane modeling were studied individually and integrated together for an airbreathing cylindrical chamber. The chamber design involves an aluminum cylinder wrapped with glass microfiber filter as transpiration membrane. Aluminum structure provides practically uniform temperature on inside surface of the membranes. Platinum mesh was used as a catalyst for rich butane-air combustion, the products of which supply the mT-SOFC. It was found that the temperature, fuel flow rate and equivalence ratio can be varied over mT-SOFC operation range. The integrated system demonstrates capability in self-sustaining power generation using hydrocarbon fuel without moving parts.
Modelling and design of highly coupled piezoelectric energy harvesters for broadband applications
Authors: Gibus D , Gasnier P , Morel A , Boisseau S , Badel A
Published: December 2019

This paper reports a method to design highly coupled piezoelectric energy harvesters with frequency tuning capabilities using nonlinear electrical techniques. A cantilever beam with two PMN-PT patches has been optimized thanks to both analytical modelling and Finite Element Methods (FEM). The built prototype exhibits a strong electromechanical coupling (k²=17.6%) and a figure of merit (km
2Q=12.4) which allow a bandwidth corresponding to 22% of the resonant frequency value.
Self-Tunable Vibration Energy Harvester
Authors: Esch J , Hoffmann D , Stojakov D , Manoli Y
Published: December 2019

In this paper we present a small self-tunable vibration energy harvester with an integrated electronic circuit board. The changing of the frequency is realized by a stepper motor which moves an anchor. By moving the anchor the effective length of the cantilever beam is changing and as a result the Eigen-frequency changes. The simulations and experimental results are shown for a proof-of-concept and a designed demonstrator in two configurations with a bandwidth of 12 to 30.5 Hz and 19 to 40 Hz. Depending on several factors the possible tuning resolution is between 0.2 and 2 Hz which allows an efficient energy harvesting in the given frequency range.
Power Enhancement of Silicon Membrane-based Thermoelectric Energy Harvester with Tailored Holey Nanostructures
Authors: Yanagisawa R. , Nomura M.
Published: December 2019

We develop SOI-based silicon membrane thermoelectric power generator with phononic crystal nanostructures. Phononic crystal nanostructures which are well designed periodic structures considering phonon mean free path enhance phonon scattering to reduce thermal conductivity of silicon membranes and improve their thermoelectric figure of merit twice. We demonstrate power enhancement of thermoelectric generator with nanostructure patterning. By using nanoimprint lithography method, we pattern this phononic crystal nanostructures in 3 x 2 mm area of silicon membrane for thermoelectric devices.
A self-sustained energy storage system with an electrostatic automatic switch and a buck converter for triboelectric nanogenerators
Authors: Zhang Hemin , Galayko Dimitri , Basset Philippe
Published: December 2019

In this paper, we present for the first time a complete energy harvesting system fo triboelectric nanogenerators (TENGs) that includes as a first stage a half-wave rectifier, and as a second stage an electrostatic automatic switch combined with a buck converter. This simple two-stage system allows to deal with the very high output voltages of TENGs: the system can power a commercial low-voltage output regulator, which cannot be realized by directly charging the storage capacitor only with diode rectifiers. Different from the previous works using dissipating transformers for voltage stepping-down or switches integrated with the TENG for impedance matching, this work demonstrates the properties of high power pumping up, potential size reduction and low power dissipations.
Compact, 3D-Printed Electron Impact Ion Source with Microfabricated, Nanosharp Si Field Emitter Array Cathode
Authors: Yang Chenye , Velásquez-García Luis Fernando
Published: December 2019

We report the design, fabrication, and characterization of a novel miniature electron impact gas ionizer manufactured via silicon micromachining and high-resolution 3D printing. The ionizer uses an array of 2,500 gated silicon nano-sharp field emitters (20 μm emitter pitch) as cathode and a set of additively manufactured, finely featured polymer and metallic parts as three-dimensional ion-generating structure. Finite element simulation of a gated field emitter tip predicts a start-up bias voltage equal to 64 V –close to the 62 V turn-on bias voltage estimated via experiments. The Si field emitter array emits 124.5 μA of electron current with ~60% gate transmission while operating at 200 V. The ionization efficiency of the gas ionizer is linear with pressure, reaching values as high as ~0.4% at 5×10−4 Torr.
Push-button Kinetic Energy Harvester with Soft-X-ray-charged Folded Multilayer Piezoelectret
Authors: Lu J , Suzuki Y
Published: December 2019

Piezoelectret using space-charged porous polymer attracts much attention recently for its softness and high piezoelectric coefficient. It has already been applied to tactile or pressure sensing as well as to kinetic/vibrational energy harvesting. In the present study, a push-button energy harvester based on soft-X-ray charged folded multilayer piezoelectret is proposed. The folded structure with CYTOP-coated parylene-C membranes yields an extremely low stiffness with effective Young’s modulus as low as 14 kPa. With the early prototype, 15.5 µJ/push has been obtained with a maximum force of only 1 N, which corresponds to the record-high piezoelectric coefficient d33 of 30000 pC/N. In addition, LED light-up is also demonstrated upon finger press.
P(VDF–TrFE) based spiral thermo-magneto-electric generators for harvesting low grade thermal energy
Authors: Kishore R A , Singh D , Kumar P , Sriramdas R , Sanghadasa M , Priya S
Published: December 2019

Low-grade thermal energy harvesting remains a challenge because of the low Carnot efficiency. Among various thermal energy harvesting mechanisms available for capturing low-grade heat (hot-side temperature less than 100°C), thermomagnetic effect has been found to be the most promising. Developing a high power density thermo-magneto-electric generator (TMEG) requires developments at both materials as well engineering levels. In this study, we propose a novel P(VDF–TrFE) based spiral-shaped cantilever beam for TMEG. Numerical simulations were performed using COMSOL Multiphysics and it was found that spiral beam experiences higher stresses, and consequently exhibits higher voltage output, as compared to rectangular cantilever beam for the same magnitude of tip deflection. Experiments revealed that the spiral structure of dimension 2.5 mm x 2.5 mm generates output voltage of about 4.0 mV, when oscillation displacement is 0.5 mm and oscillation frequency is 1 Hz. The output voltage increases with increase in tip deflection as well as oscillation frequency and a peak voltage of 25 mV is obtained at oscillation frequency of 10 Hz.
Electric-field controlled magnetic reorientation in exchange coupled CoFeB/Ni bilayer microstructures
Authors: Xiao Zhuyun , Lo Conte Roberto , Goiriena Maite , Chopdekar Rajesh V. , Li Xiang , Tiwari Sidhant , Lambert Charles-Henri , Salahuddin Sayeef , Carman Gregory P. , Wang Kang , Bokor Jeffrey , Candler Rob N.
Published: December 2019

A novel strain-mediated composite multiferroic system is investigated in this work. The system is composed of magnetostrictive microstructures made of a ferromagnetic bilayer of negative magnetostrictive Ni and positive magnetostrictive CoFeB fabricated on a ferroelectric Pb(Mg1/3Nb2/3)0.69Ti0.31O3(PMN-PT) single crystal substrate. When an electric field is applied across the PMN-PT substrate, magnetization reorientation occurs in the microstructures that are predominantly initialized into flux-closure states. An x-ray magnetic circular dichroism-photoemission electron microscope is used to experimentally visualize the electrically induced changes of the magnetization state of the individual layers as well as the exchange coupling between the two layers. Such heterostructures with tunable magnetoelectric properties have potential for new magnetic memory and sensor applications.
Supercapacitive Micro-Bio-Photovoltaics
Authors: Liu Lin , Mohammadifar Maedeh , Choi Seokheun
Published: December 2019

We created innovative supercapacitive micro-bio-photovoltaic systems (or micro-BPVs) with maximized bacterial photoelectrochemical activities in a well-controlled, tightly enclosed micro-chamber. The technique was based on a 3-D double-functional bio-anode concurrently exhibiting bio-electrocatalytic and charge-storage features so that it offers the high-energy harvesting function of BPVs and the high-power operation of an internal supercapacitor for charging and discharging. During the charging-discharging operation with 3 min of charging and 2 min of discharging, our device produced a maximum power density of 19.12 μW/cm2and current density 212.09 μA/cm2, a performance significantly greater than that of the continuous discharging mode. This work creates a microscale hybrid energy-harvesting device that combines a biological photovoltaic device and a supercapacitor for self-sustainable field applications.
A complete tattoo-based wireless biofuel cell using lactate directly from sweat as fuel
Authors: Escalona-Villalpando R.A. , Ortiz-Ortega E. , Bocanegra-Ugalde J. P. , Minteer S. D. , Arriaga L.G. , Ledesma-García J.
Published: December 2019

In this work, an enzymatic type wireless biofuel cell (BFC) has been implemented. The bioanode consisted in the immobilization of the enzyme lactate oxidase (LOx) with the dimethylferrocene-modified redox polymer linear polyethylenimine LPEI (FcM2-LPEI) and 5 % EDGE at a volumetric ratio of 56/24/3 and thoroughly mixed. The biocathodes were prepared immobilizing bilirubin oxidase (BOx) mixed with 7.5 mg of multi-walled carbon nanotubes MWCNT modified with anthracene and TBAB-Nafion by successive vortex mixing/sonication steps and the paste was deposited qualitatively on flexible Toray carbon (TC-PTFE) using a brush. The cyclic voltammetry results of the bioanode and biocathode show an enzymatic activity in the lactate oxidation and oxygen reduction reactions in PBS and human sweat respectively. The evaluation of BFC tattoo was performed in different parts of the body under conditions of exercise by a healthy volunteer, finding that located on the chest, was obtained the greatest current (96 μA) with 0.55 V of OCP monitoring the system using a potentiostat and a wireless controlled device.
Virus-assembled technology for next generation bioenergy harvesting devices
Authors: Chu Sangwook , Brown Adam D , Culver James N , Ghodssi Reza
Published: December 2019

This work reports Tobacco mosaic virus (TMV)-based assembly of glucose oxidase (GOx) electrodes for the development of advanced enzymatic biofuel cells (EBCs). Cysteine-modified TMV (TMV1cys), self-assembled on Au electrodes, has served as a template for augmenting the GOx immobilization density via a robust chemical conjugation route. Enhanced enzymatic activity of the TMV1cys/GOx electrodes have been confirmed via colorimetric assay, and the electrochemical transduction of the catalytic reactions via mediated electron transfer resulted in a ~25-fold increase in electrochemical current compared to previous work using a similar strategy. This enhancement is attributed to the on-chip bioconjugation strategy presented in this work, leveraging the robust and high density self-assembly of TMV1cys on Au surface. The performance of an EBC consisting of TMV-assembled enzyme electrodes is reported for the first time, generating a maximum power density of 860 nW/cm2.
Development of A High-performance Amorphous Fluorinated Polymer Electret Based on Quantum Chemical Analysis
Authors: Kim Seonwoo , Suzuki Kuniko , Suzuki Yuji
Published: December 2019

In the present study, for the first time, a novel high-performance amorphous fluorinated polymer electret based on quantum chemical analysis is proposed. Density functional theory is adopted to analyse the electron affinity of CYTOP polymers with different end groups. In analysis of CYTOP series with different end groups, it is found that the amide bond at the end of CYTOP chain attract electron, leading to high electron affinity of the molecule. Based on the DFT results, a new electret material has been developed by adding Tris(2-aminoethyl)amine (TAA) into CYTOP CTX-A. With a 15 µm-thick film, a record-high surface charge density of -4 mC/m2 has been obtained. It is also found from the thermally stimulated discharge experiment that the electron trapped in the CTX-A/TAA have higher thermal stability than CYTOP EGG, which is known as the best fluorinated polymer electret.
Self-Rechargeable Electret based on Vibration Energy Harvester
Authors: Zhang Yulong , Hu Yushen , Wang Meihua , Wang Fei
Published: December 2019

In this paper, we propose a new method to corona charge the electret after device packaging, based on the common electret based electrostatic vibration energy harvester (e-VEH) with the out-of-the-plane gap closing scheme. Combined with a new portable corona charging system, the electret in the device has been charged successfully. Here, new portable corona charging system is designed to be powered by another e-VEH directly. In our demo, one e-VEH powers the portable corona charging system first, and then the system releases the energy to corona charge the electret in the other device through some build-in corona tips. After charging, the electret possesses a uniform surface potential, and the device shows a better power output then before charging. In the future, if the surface potential of the electret decays after the e-VEH has been working for a long time, we can also use this new method to recharge the electret directly.
A Long-Lasting Microliter-Scale Microbial Biobattery Using Solid-State Ionics
Authors: Mohammadifar Maedeh , Choi Seokheun
Published: December 2019

We report a microliter-scale bacteria-powered biobattery providing a long-term operational capability for potentially powering unattended wireless sensor networks. In a 20μL-chamber, the biobattery contained a horizontally arranged anode/salt-bridge/cathode configuration with solid-state agar electrolytes. A slow release of bacterial nutrients from a synthetic solid anolyte enabled a continuous current generation (> 6μA/cm2) over 8 days while a liquid-based anolyte was completely depleted within 4 hours. Given that wireless sensors require an ultra-low power intermittently, our micro-biobattery can be practically used for more than a month without human intervention. Agar-based catholyte and salt bridge further enhanced the device lifespan and ensured its practical feasibility as a power source for wireless sensors. The device was sealed with a gas-permeable polydimethylsiloxane (PDMS) membrane to facilitate gas exchange to the bacteria and cathodic reactions, even ideally allowing for replenishing bacterial nutrients from environments for self-sustainable energy harvesting. Our device used Shewanella oneidensis MR-1 to produce a maximum power density of 4μW/cm2 and current density 45μA/cm2 after 96 hours (day 4), which will be enough power for small-power applications.
Piezoelectric and Pyroelectric Energy Harvesting from Lithium Niobate Films
Authors: Clementi G , Margueron S , Suarez M A , Baron T , Dulmet B , Bartasyte A
Published: December 2019

Single-crystalline LiNbO3films were studied as a pyro- and piezo-electric transducer for energy harvesting applications. Two types of devices: piezoelectric cantilever (PiEH) and pyroelectric chip (ThEH) were microfabricated. Different types of characterization were done, starting from a comparison of finite element method (FEM) simulated eigen-frequencies of cantilever beam and optical vibrometer measurements. According to electrical characterization, resonance frequencies of two cantilevers with different thickness were 1.26 kHz and 485 Hz with generated spontaneous power of 14 μW and 4 μW at 275-300 kΩ, respectively. Finally thermal characterization of pyroelectric samples showed voltage amplitudes ranging from 1 to 2.5mV in the temperature range of 50-200 °C.
MISTIC - Micro Stirling Heat Engines for Thermal Energy Harvesting
Authors: Avetissian T. , Leveillé É. , Hachey M.-A. , Formosa F. , Fréchette L. G.
Published: December 2019

This paper reports on the fabrication and validation of the piston assembly for a new micro heat engine based on the Stirling cycle, (MISTIC - MIcro STIrling Clusters), intended for electric power generation by harvesting low temperature waste heat (≥ 200° C). Here, we define the requirements, develop the fabrication processes and fabricate piston assemblies to show the feasibility. Static and dynamic response of the pistons show that high quality factors (Q>100) are achievable with the polymer structures and the natural frequencies of adjacent pistons can be matched (within 4 percent), two characteristics required to allow start-up of the engine. We also demonstrate an electromagnetic actuator that is capable of individually exciting the pistons to further facilitate start-up.
Synchronous circuits with self-adaptive mechanical switches of viscous material: a parameter study
Authors: Yuan Zhongxin , Liu Weiqun , Tian Wendi , Huang Yao , Zhao Zixiang
Published: December 2019

Dedicated units are generally needed for operating the switches in synchronous extraction circuits which are considered to be effective in enhancing the power of piezoelectric generators. This paper presents a novel design of self-adaptive mechanical switch using viscous materials. It can trace the displacement peaks and perform the switching operations synchronously with higher performance, less electronic components and lower voltage threshold. A parameter study shows that the relaxing time of the viscous material has different effects in the case of harmonic and noise excitations with varied optimization goals.
Wearable Triboelectric Generator based on a Hybrid Mix of Carbon Nanotube and Polymer Layers
Authors: Su M , Brugger J , Kim B J
Published: December 2019

A novel single-layer structured triboelectric generator (TEG) is proposed with a hybrid mix of carbon nanotube (CNT) and silk. Here, the mixing of two materials in liquid phase for proven effective power generation is shown. In this research, CNT provides the function of conductivity, whereas silk fibroin forms the main triboelectric generation material that is uniformly mixed with CNT, to achieve a conductive film with superior electric power generation capability. The newly proposed TEG shows very good electrical performance and great potential in simplifying TEG’s structure and manufacturing process, enhancing their feasibility in future wearable applications.
A Pd/Al2O3-based micro-reformer unit fully integrated in silicon technology for H-rich gas production
Authors: Bianchini M , Alayo N , Soler L , Salleras M , Fonseca L , Llorca J , Tarancon A
Published: December 2019

This work reports the design, manufacturing and catalytic activity characterization of a micro-reformer for hydrogen-rich gas generation integrated in portable-solid oxide fuel cells (μ-SOFCs). The reformer has been designed as a silicon micro monolithic substrate compatible with the mainstream microelectronics fabrication technologies ensuring a cost-effective high reproducibility and reliability. Design and geometry of the system have been optimized comparing with the previous design, consisting in an array of more than 7x103 vertical through-silicon micro channels perfectly aligned (50 μm diameter) and a 5 W integrated serpentine heater consisting of three stacked metallic layers (TiW, W and Au) for perfect adhesion and passivation. Traditional fuels for SOFCs, such as ethanol or methanol, have been replaced by dimethyl ether (DME) and the chosen catalyst for DME conversion consists of Pd nanoparticles grafted on an alumina active support. The micro-channels have been coated by atomic layer deposition (ALD) with amorphous Al2O3 and the influence of rapid thermal processing (RTP) on such film has been studied. A customized ceramic 3D-printed holder has been designed to measure the specific hydrogen production rates, DME conversion and selectivity profiles of such catalyst at different temperatures.
Magnetic Pendulum Arrays for Efficient Wireless Power Transmission
Authors: Mysore Nagaraja S P , Tok R U , Zhu R , Bland S , Propst A , Wang Y E
Published: December 2019

In this paper we would like to propose an innovative electromechanical transmitter called Magnetic Pendulum Array (MPA), for efficient wireless power transmission at Ultra Low Frequencies (ULF). We take advantage of the high Quality (Q) factor and low dissipation in the electromechanical system to demonstrate efficient power transfer. It has been shown that using Magnetic Pendulum arrays leads to about 10dB% higher power transfer efficiency at the resonance frequency of 447 Hz as compared to a coil of similar dimensions.
A mechanically tunable GHz passive voltage element using microstrip resonator
Authors: Ni Di , Ravi Adarsh , Vinaya Kumar K B , Lal Amit
Published: December 2019

The ability to detect very low RF signals can be used to wake-up a sensor node only when needed to sense or transmit data, reducing the sensor node power consumption. A passive voltage transforming stage from the antenna to a nano-watt receiver can be useful to reduce the minimum detectable RF signal. At high RF frequencies, the transformer is harder to implement owing to the low impedance of load capacitive loads. We demonstrate a gigahertz frequency range passive voltage transformer, using a mechanically tunable strip-line resonator at 1-2 GHz. The transformer exhibited a 19.5dB gain at 1.007 GHz and achieved gains over 19dB with load capacitances of 0.8-2.4pF. A piezoelectric AlN GHz transducer was also used to measure the gain of the resonator. An RF waveguide model has been developed which matches experiments well for both frequency and gain responses.
Development of thermoelectric thin films and characterization methods
Authors: Mori T , Aizawa T , Mitani S , Tsujii N , Ohkubo I , Tynell T , Kakefuda Y , Baba T , Mitome M , Kawamoto N , Golberg D
Published: December 2019

This work reports on the fabrication of thin films of inorganic thermoelectric materials like borides, germanides, manganese compounds, and characterization of their thermoelectric properties. We have utilized a unique high temperature molecular beam epitaxy (MBE) apparatus to grow hexaboride thin films and manganese germanides. Magnetic manganese based alloy thin films were also grown using sputtering, since we are interested in the possibilities of utilizing magnetism to develop thermoelectric materials.
Optimization of Carbon Electrodes for Solid-State E-Textile Supercapacitors
Authors: Hillier N , Yong S , Beeby S
Published: December 2019

The integration of flexible supercapacitors (FSC) into electronic textiles (e-textiles) offers a promising power source, capable of fast charge-discharge rates, high-power density and long lifetimes. The design parameters for such a device are varied and complicated, with the need for low weight, cheap production, breathability and low toxicity. This work presents the optimization of the carbon electrodes within a solid-state, single-layer textile supercapacitor that meets these device requirements. Three commercial activated carbons are investigated with different ratios of activated carbon to Carbon Black, at differing loading levels. The maximum areal capacitance observed was 23.6 mF.cm−2
Miniature, 3D-Printed, Monolithic Arrays of Corona Ionizers
Authors: Sun Zhumei , Velásquez–García Luis F
Published: December 2019

We report the design, fabrication, and characterization of the first 3D-printed, monolithic corona ionizer arrays (CIAs) in the literature. The CIAs are binder inkjet-printed in stainless steel 316L and have 5, 9, or 32 emitters (emitter pitch equal to 6 mm, 4 mm, or 2 mm, respectively); each emitter is 5 mm tall, with 1.7 mm diameter at the base and 300 μm diameter at the tip. Current-voltage data were collected in air with the emitter array biased negatively with respect to a counter-electrode for varying inter-electrode separation; the current divided by the bias voltage has a linear dependence with respect to the bias voltage minus the onset voltage –in agreement with the Townsend current-voltage law. 3D finite element simulation of the electrostatics of the densest CIA using the COMSOL Multiphysics evidences that the emitters at the periphery of the array have the highest electrical field, while a 1D electrohydrodynamic model implemented in the same software predicts a 400 μm-thick corona region surrounding the corona tip.
Generation of asymmetric incommensurable torque signals
Authors: Kurmann L. , Duarte J.L.
Published: December 2019

Asymmetric incommensurable torque signals can be achieved by exploiting magnetic nonpolar repulsion techniques, see also [1], aiming at designing kinetic energy harvester (KEH) systems. This paper confirms by using three different simulation methods that an asymmetric incommensurable torque signal is feasible to be reached, exploiting non-conservative magnet fields. All shown calculations are in full agreement with the classical Electromagnetic Theory. The first method (I) is based on time consuming full 3D FE generated torque and force signals. The second method (II) is using also FE generated torque and force signals, but they are calculated only in orthogonal directions, approximated with Fourier Series and normalized to provide 2D stiffness signals. The third approach (method III) focuses on filamentary current rings to calculate the magnetic field of permanent magnets (PM) to generate in a purely analytically way the same force and torque signals as in the previous methods. However, only speculation about the energy source as required to maintain the forecasted persistent torque can be given.
Graphene-porous semiconductor nanocomposites scalable synthesis for energy applications
Authors: Dupuy A , Sauze S , Jellite M , Arvinte R , Arès R , Boucherif A
Published: December 2019

The aim of this work is to develop a cost effective and scalable fabrication process for graphene-enhanced porous semiconductor nanocomposite (GPNC). This class of materials combines the remarkable properties of graphene with the unique properties of porous semiconductors, such as porous silicon (PSi) and porous germanium (PGe). The experimental results show that these nanocomposites are chemically resistant to most of the commonly used microfabrication solutions and have enhanced electrical and thermal properties. Besides, we demonstrate the potential of graphene-porous germanium nanocomposite (GPGNC) for energy storage application.
Hydrogen Evolution Catalytic Performance of Metal Doped MoS2
Authors: Leng X , Wang Y , Wang F
Published: December 2019

Metal doped Molybdenum disulphide (MoS2) has been synthesized through hydrothermal method. The layer distance of MoS2 has not changed due to the tiny doping amount of metal element while the hydrogen evolution catalytic performance has been modified. The structure and morphology has been observed through SEM and XRD pattern. Hydrogen evolution reaction has been carried out in a standard three electrode system and the results showed that doped MoS2 performed good catalytic activity. Both Co and Fe showed obvious improvement in the catalytic performance.
A cm-scale, low wind velocity and 250°C-compliant airflow-driven harvester for aeronautic applications
Authors: Gasnier P , Willemin J , Boisseau S , Goubault De Brugière B , Pillonnet G , Gomez B , Neyret I
Published: December 2019

This paper reports the design, fabrication, and testing of a centimeter-scale (Ørotor=35mm), 250°C-compliant microturbine for aeronautic applications. Dedicated to low-speed air flows (≈3 m/s and down to 2 m/s), this device is the first flow-driven harvester withstanding such high temperatures and high vibration levels (10
7
cycles at 20G). Furthermore, the proposed harvester exhibits the highest output power per unit cross sectional area compared to prior art in the cm-scale and low velocity ranges.
Wearable generator with rotating oscillating mass
Authors: Ortiz M , Fenollal E , Restrepo B , Espinoza A , Romero E
Published: December 2019

This paper reports the design, fabrication, and testing of a rotating, oscillating mass electromagnetic generator for wearable applications. This work presents a custom design architecture to evaluate the differences in generation output for swinging motion when driven at different frequencies, and load conditions. Body movement is characterized by large amplitude motion, such as the limbs when walking, whereas machine vibration displacement is relatively small and well catered with linear energy harvesters. The proposed study evaluates a rotational generator mounted on a swinging arm driven by a sinusoidal input motion to determine the parameters that lead to higher power output. Power measurement up to 0.25 μW was generated under sinusoidal input motion.
Dynamic Analysis of Electrostatic Energy Harvesting Device with Multi-step Structure
Authors: Guo Xinge , Zhang Yulong , Wang Fei
Published: December 2019

In this paper, the dynamic features of an electrostatic energy harvester with out-of-the-plane gap closing scheme has been studied with different stopper heights and surface potentials. The displacement and output power of the devices with various stopper heights have been simulated, measured and analysed and “pull-in” effect has been considered. The “pull-in” effect is observed for device with high surface potential, which limits the output power. And a decrease of output power for device with higher stoppers and same gap and acceleration is also noticed, which is different from the phenomenon observed previously. The dynamic analysis of the device will facilitate the design of electrostatic vibration based energy harvesters.
Equivalent circuit model of piezoelectric vibration energy harvesters composed of trapezoidal unimorph cantilevers
Authors: Umegaki Toshihito , Ito Takashi , Tan Goon , Kanno Isaku
Published: December 2019

We have constructed a time-resolved equivalent circuit model of the piezoelectric vibrational energy harvesters (PVEHs) with the trapezoidal unimorph structure not only to optimize the dimensional parameter of trapezoidal PVEHs but also to anticipate the output power by a variety of external vibrations. To calculate the output responses by arbitrary mechanical input accelerations such as impulses or sinusoidal, we have formulated simultaneous first order differential equations based on this model. In order to express dynamics with large amplitudes enough to drive actual devices such as micro-sensors with BLEs, we have considered the nonlinear effects, and successfully reproduced experiments by our calculations.
Determination of mechanical force generated by growing seed in inkjet 3D printed microdevice
Authors: Adamski K , Kawa B , Dziuban J , Walczak R
Published: December 2019

An inkjet 3D printed microdevice for germinating seed root and stalk driving force measurement is proposed. The device consists of two cantilever-type sensors for the forces monitoring. The cantilevers are first mechanically characterized by force-deflection measurements. Deflection of the cantilevers in the microdevice is determined by optical analysis of the captured “micropot” images. Then deflection is converted to force value. Successful monitoring of the root and stalk driving forces in different cultivation mediums was achieved.
Dynamics of direct hydrocarbon polymer electrolyte membrane fuel cells
Authors: Kong E H , Ronney P D , Surya Prakash G K
Published: December 2019

Hydrocarbons have 50-100 times higher energy per unit weight compared to commercially available batteries, thus harvesting only 10% of the energy from hydrocarbons could provide a far lighter energy source for portable electronic devices. With this motivation, the feasibility of using polymer electrolyte membrane fuel cells with propane fuel, operating at low temperatures (< 100˚C), was explored. It was interesting to note that there was a significant influence of the current history on the fuel cell performance. In particular, at higher current densities (>24 mA/cm2) the power output gradually decreases then rapidly “extinguishes” (i.e., produces no power). However, by employing an unconventional operating mode (load-interrupt) where the current is shut off for a short period of time and then reapplied, the average maximum power density increased to 11.6 mW/cm2. Furthermore, the extinction of the fuel cell can be further improved by seeding a small amount of unsaturated hydrocarbons (~2000ppm) into the fuel stream and can extend the lifetime of the fuel cell by more than 10 times.
Improved sensitivity of thin film sensor for humidity measurement inside a operating PEMFC
Authors: Hasegawa Noriyoshi , Otsuki Yota , Kurosu Masato , Araki Takuto
Published: December 2019

Water management inside a proton exchange membrane fuel cell (PEMFC) is an important issue for improving the performance of a PEMFC. It is necessary to understand water transport phenomena inside a PEMFC for water management. Especially humidity measurement near the membrane electrode assembly is indispensable. In order to measure the humidity, we fabricated the capacity type humidity sensor with thickness of 7 μm using micro-electro-mechanical system techniques. In addition, in order to measure the humidity locally, we reduced the parasitic capacitance by changing the shape of the sensor, and improved the sensitivity of the sensor by carrying out O2 plasma etching on the humidity sensitive layer. Finally, the improved sensor was inserted between the catalyst layer and micro porous layer inside a PEMFC, and the humidity inside it during power generation was measured to confirm that the sensor was functioning.
Microfabrication of a Silicon Turbopump with Embedded Thermal Isolation for a Rankine MEMS Heat Engine
Authors: Amnache Amrid , Fréchette Luc G.
Published: December 2019

This paper presents the fabrication of a silicon MEMS microturbopump with embedded thick thermal isolation, covering the key building blocks to incorporate thermally insulated zones in a multiple wafer stack, and the resulting device. Thermal insulation is a roadblock for the implementation of heat engines at the MEMS scale. To implement the Rankine cycle on a chip, insulation is required to prevent boiling of water in the pump while the turbine is exposed to high temperature vapour flows. To prevent heat from conducting through the silicon rotor, thick glass insulation was embedded into the rotor structure using glass molding and planarization. This composite rotor approach allows us to leverage the capabilities of silicon DRIE, while creating over 100 micron thick glass insulation between the turbine and the pump. Also, in-plane thermal insulation is required between the central pump zone and the surrounding fluid film bearings, fed with steam. This was accomplished by etching deep trenches in silicon to form an array of thin walls, followed by a thermal oxidation step that consumes the silicon walls and closes the trenches to form a deep monolithic oxide zone. These techniques were successfully implemented for the fabrication of a complete MEMS turbopump, which consists of a stack of 4 silicon wafers and one glass wafer, and a total of 18 lithography/etch steps.
A narrow-band and ultra-low-power 433 MHz wake-up receiver
Authors: Koeble S , Heller S , Woias P
Published: December 2019

For the design of wireless sensor nodes (WSNs) the inclusion of a wake-up receiver becomes interesting as soon as an asynchronous bidirectional communication between the WSN and its host is mandatory, to e.g. reprogram the WSN or to trigger the delivery of data. For these purposes the use of the WSNs standard RF interface is not suitable in most cases, as the high power consumption of the same may drain the WSNs battery or overload the capabilities of an integrated energy harvesting module. To solve this principal conflict between flexibility and power consumption, we present the design and characterization of an ultra-low-power wake-up receiver. The concept is based on an optimized modulation/demodulation concept, to achieve a high RF sensitivity and narrow-band operation at the same time. The final device works in the license-free 433 MHz frequency band, with a high RF sensitivity of -63.4 dBm, an ultra-low power consumption of 8.7 µW, and with a low supply voltage of 2 V only.
A Papertronic Sensing System for Rapid Visual Screening of Bacterial Electrogenicity
Authors: Tahernia Mehdi , Mohammadifar Maedeh , Choi Seokheun
Published: December 2019

In this work, we report a papertronic sensing system with the ability to achieve easy, rapid, and sensitive characterization of bacterial electrogenicity from a single drop of culture. Paper was used as a device substrate that inherently produces favorable conditions for easy, rapid, and sensitive and potentially high-throughput controlling of a microbial liquid sample. Through an innovative microscale device structure and a simple transistor amplifier circuit directly integrated into a single sheet of paper substrate, a powerful sensing array was constructed, resulting in the rapid and sensitive characterization of bacterial electrogenicity from a microliter sample volume. The microbial current generations were amplified by the transistor providing power to a 4-wide LED circuit board indicator bar for the direct visual readout with the naked eyes. Depending on bacterial electrogenicity, the LED intensity was changed. We validated the effectiveness of the sensor using two known bacterial electrogens (wild-type S. oneidensis and P. aeruginosa) and hypothesis-driven genetically modified P. aeruginosa mutant strains.
Glucose oxidase bioelectrodes in devices implanted in living plants for energy applications.
Authors: Galindo-de-la-Rosa J. , Hernández-Torres A. , Araiza-Ramírez M.G. , Arriaga L.G. , Ledesma-García J.
Published: December 2019

The growth of the world population and the lack of energy supply have led to the development of technologies to obtain alternative energy that has a minimal environmental impact, as is the case of fuel cells. In this work, the development of electrodes using glucose oxidase enzyme immobilized with functionalized carbon nanofibers on graphite rods is proposed for its application in a fuel cell implanted in living plants, specifically in cacti. The purpose is to convert solar energy to chemical and then, to electric energy, carrying out the glucose oxidation contained in these plants. The use of a living plant as a fuel cell comes from the idea of taking advantage of more efficiently the conversion of chemical energy, which comes from the plant’s photosynthesis until is converted into electrical energy.
Thin-Film π-Type Micro TEG Using Vacuum/Insulator-Hybrid Isolation with Convex-Shape Hot-Plate Module Structure for Wearable Device Applications
Authors: Shiotsu Y , Seino T , Chiwaki N , Sugahara S
Published: December 2019

Design optimization and performance of a micro thermoelectric generator (μTEG) using human body heat are investigated. A newly introduced thin-film π-type μTEG module structure using vacuum/insulator-hybrid thermal isolation with the convex-shape hot plate is useful to achieve a high thermal resistance of the module and also to suppress the unwanted heat flow passing through the supportive wall structure for the vacuum isolation. The optimum design of this μTEG module can exhibit sufficiently high output power suitable for a power source of self-powered wearable devices.
A Voltage-Boost Rectifier Circuit for Energy Harvesting from Environmental Vibrations
Authors: Tohyama Y , Honma H , Ishihara N , Sekiya H , Toshiyoshi H , Yamane D
Published: December 2019

We propose a VBR (voltage-boost rectifier) circuit based on the 0.18-μm Si CMOS (complementary metal oxide semiconductor) technology, which is designed for vibrational energy harvesters utilizing environmental vibrations. The VBR employs a single-end Dickson type charge-pump topology, and the circuit would be realized as a monolithic chip. The evaluation results obtained by multi-physics simulations on a circuit simulator reveal that the proposed circuit can deliver boosted DC voltage from the input of sub-threshold AC voltage.
Design of a MEMS relay based on SOI fabrication technology
Authors: Schwarz M. , Lambrecht F. , Bauer A. , Seidel H.
Published: December 2019

The deployment of MEMS relay for high power switching applications requires a matrix-like arrangement of many single MEMS relay units. For consistent performance the sameness of the individual switches representing the array is crucial. We present the design, simulation and fabrication of a MEMS relay based on silicon-on-insulator (SOI) technology. The measurement results show high accordance with simulations confirming the predictability and thereby the homogeneity of SOI-based MEMS relays.
Laser-bonding of FEP/FEP interfaces for a flexible manufacturing process of ferroelectrets
Authors: Flachs D. , Emmerich F. , Roth G.-L. , Hellmann R. , Thielemann C.
Published: December 2019

This paper presents an optimized laser-bonding process for piezoelectric energy-harvesters based on thin fluorinated-ethylene-propylene (FEP) foils, using an ultra-short-pulse (USP) laser. Due to the minimized thermal stress in the material during bonding, achieved by pulse durations of few picoseconds, we created seams down to 40 µm width without generating holes in the 12.5 µm thick FEP-foils. Using a galvanometer scanning system allowed for fast bonding-speed up to several centimeters per second, making the process also suitable for large structures and areas. The achieved bond strength of the seams under influence of shearing stress was examined using tensile testing, which showed a sufficient strength of about 25 % of the maximum strength of an unbonded, single layer of FEP.
Ethanol Tolerant Catalyst Based in Platinum and Silver in Graphene
Authors: Estrada-Solís M. J. , López-González B. , Guerra-Balcázar M. , Cuevas-Muñiz F.M.
Published: December 2019

In this work, the use of the electrochemical deposit PtAg on the glassy carbon modified with graphene (PtAg/G) is proposed. The electrochemical test (Rotatory Disc Electrode, RDE) showed a better performance to reduce oxygen for PtAg/G compared to a similar material obtained in Vulcan carbon (PtAg/V). The reduction potential is around 0.82 V versus RHE in PtAg/G compared to 0.77 V versus RHE in PtAg/V. The PtAg/G has a smaller particle size, this was attributable to the better distribution of active graphene sites.
PLD Electrodes in a coupled microfluidic fuel cell to a lab on a chip system for energy generation.
Authors: López-González B. , Abrego-Martínez J. C. , Hernández-Sarmiento B. S. , Moreno-Zuria A. , Wang Youling , Mohamedi Mohamed , Arriaga L.G. , Cuevas-Muñiz F.M.
Published: December 2019

An inorganic microfluidic fuel cell (i-μFFC) was integrated in a glucose sensor LOC device. This device was constructed by using a mini CNC and evaluated for energy harvesting from glucose. The i-μFFC with PLD electrodes exhibits the highest performance compared to the i-μFFC with spray electrodes microfluidic fuel cell for the three conditions, obtained the best performance in alkaline conditions (3.53 μW), which is enough energy to power low-consumption microelectronic chips or microsensors.
A Compact Electromagnetic Vibration Energy Harvester with High Output Voltage
Authors: Wang Xingchang , He Xuefeng , Li Kankan , Jiang Senlin
Published: December 2019

Non-resonant vibration energy harvesters (VEHs) attract much attention for the excellent performance in scavenging ambient low-frequency and broadband vibrations. In this paper, effects of the mild steel sheets, thicknesses of the magnets and coils, wire diameter of coils, and inner dimension of the coils on the outputs of a non-resonant electromagnetic vibration energy harvester (EMVEH) were simulated and the optimized geometries was obtained. Numerical simulations show that the mild steel sheets can enlarge the magnetic flux density about 25.0%, agreeing well with the experimental result that the output voltage increased about 29.3%. Under a base excitation of 0.3 g (where 1g = 9.8 m s−2) at 8.3 Hz, the RMS voltage across a 10.4 kΩ resistor of an EMVEH prototype, with the inner volume of 76.26 cm3, is about 15.53 V. The power density is about 304 µW cm−3, about 18.7% higher than the previous device.
Heating Performance by an Insole Energy Harvester
Authors: Rahman M M , Noh S , Kim K H , Kim H
Published: December 2019

This paper reports the heating performance of the previously reported 4th generation shoe-insole-based hydraulic electromagnetic energy harvester (HEEH) [1] in connection with a micromachined polysilicon heater & a commercial copper heater [2]. The HEEH produced 455.77mW of power by using a 4-channel configuration under an actuation frequency of 3Hz. It was integrated with two types of heaters to produce temperature rises of 2.0 & 3.2°C and the heating rates of 12.0 & 1.6°C/min, respectively, from polysilicon (0.15×0.1mm2, 6.05e−6s of the thermal time constant) and copper heaters (78×28mm2, 8.31s of the thermal time constant). Such heating performance of the HEEH is the 1st results of its kind by energy harvester [3, 4, 5].
Pendulum base 3D printed electromagnetic energy harvester
Authors: Adamski Krzysztof , Walczak Rafał
Published: December 2019

In this paper we present for the first time results of works on pendulum base energy harvester fabricated by inkjet 3D printing technology. 3D printing is recognising as a technology that can change the word. First results of harvester operation shows that it is possible to harvest energy in this device with maximal generated voltage near 1.8 V. Printing of this harvester take 12 h and material costs are near 15 USD. It seem that it is possible to utilise this device to power supply a wearable sensors network. Also proposed energy harvester can be used as a simple pedometer.
Systematic comparison of basic structures for electromagnetic energy harvesters using an automated design methodology
Authors: Leistritz Bianca , Kattanek Wolfram
Published: December 2019

This paper focuses on the systematic comparison of different basic structures for electromagnetic energy harvester to increase the power density of the converters. The goal is to select the optimal basic structure depending on the specific requirements. To achieve this, an automated design methodology was developed and implemented in MATLAB®. The systematic comparison and automation allows a cost-effective design of adapted energy harvesters for application-specific requirements. In studies, the influence of different boundary conditions on the evaluation of basic structures was investigated. It can be shown that none of the structures always delivers the highest output power.