A hybrid piezoelectric and electrostatic energy harvester for scavenging arterial pulsations

Implantable and wearable biomedical devices suffer from a limited lifespan of on-board batteries which results in a requirement to change the battery or the device itself causing additional physical discomfort. In order to overcome this, various energy harvesters have been developed. The human body possesses several types of energy available for scavenging through appropriately designed energy harvesting devices, while cardiovascular system in particular represents a constant reliable source of mechanical energy from vibration. Most conventional energy harvesters exploit only a single phenomenon, such piezo- or triboelectricity, thus producing reduced power density. As an improvement, hybridisation of energy harvesters intends to negate this drawback by simultaneously scavenging energy by multiple harvesters. In the present work, the reverse electrowetting on dielectric (REWOD) phenomenon is combined with the piezoelectric effect in a proof-of-concept hybrid harvester for scavenging biomechanical energy from arterial or other type pulsations. A mathematical model of the harvester was developed, and a computational investigation using CFD, and fluid-structure interaction simulations were carried out using the COMSOL Multiphysics software. The effect of the materials of piezoelectric film and geometrical features of the harvester on parameters such as the displacement, the frequency of pulsations and the energy produced were studied. An experimental setup that could imitate the displacements caused from arterial pulsations was designed and the produced electrical energy characteristics were analysed. A comparison between experimental and computational data was carried out and demonstrated a good agreement. Dependencies between geometrical parameters and electrical output were obtained, recommendation on piezoelectric materials and design solutions were provided

Programme and The Book of Abstracts / Eighteenth Annual Conference YUCOMAT 2016, Herceg Novi, September 5-10, 2016

The First Conference on materials science and engineering, including physics, physical chemistry, condensed matter chemistry, and technology in general, was held in September 1995, in Herceg Novi. An initiative to establish Yugoslav Materials Research Society was born at the conference and, similar to other MR societies in the world, the programme was made and objectives determined. The Yugoslav Materials Research Society (Yu-MRS), a nongovernment and non-profit scientific association, was founded in 1997 to promote multidisciplinary goal-oriented research in materials science and engineering. The main task and objective of the Society has been to encourage creativity in materials research and engineering to reach a harmonic coordination between achievements in this field in our country and analogous activities in the world with an aim to include our country into global international projects. Until 2003, Conferences were held every second year and then they grew into Annual Conferences that were traditionally held in Herceg Novi in September of every year. In 2007 Yu-MRS formed two new MRS: MRS-Serbia (official successor of Yu-MRS) and MRS-Montenegro (in founding). In 2008, MRS – Serbia became a member of FEMS (Federation of European Materials Societies)

Carbon and Platinum Nanostructured Electrodes on Miniaturized Devices for Biomedical Diagnostics

Nowadays, medical devices face several limitations concerning rapid, reliable and simultaneous quantification of a set of ions and metabolites from a micro-nanoliter volume of undiluted samples. The development of minimally-sized devices is, therefore, of key importance. In such a context, electrochemical sensors are particularly advantageous because of the simple, low cost and reproducible fabrication procedures and the rapid analytical measurements. Moreover, they provide easy possibilities for continuous monitoring. However, sensitive and selective detection of molecules in the physio-pathological concentration range is very challenging when conventional electrochemical devices are employed, especially for long-term use. Nanostructured electrodes are considered as one of the most promising strategies to overcome issues of sensitivity because of their large surface area and their excellent electrocatalytic properties. They could also address in part the problem of selectivity due to shifts in potential of the measured Faradic currents. In addition, nanomaterials could provide stable and reproducible potential responses when used as solid-contact materials of ion-selective electrodes. Inappropriate nanointegration methods could decrease the sensor performance so that the development of tailored nanostructuration protocols is extremely important to boost the sensor sensitivity, selectivity and stability over time. Objective of this thesis was to design and electrochemical characterise novel carbon and metal nanostructures for medical sensors. First of all, the integration of carbon nanomaterials on specific sensing sites of a microfabricated sensor was considered. Time-consuming, expensive and hardly-reproducible nanostrucuturation approaches contemplate the co-immobilization of carbon nanomaterials and additives whose presence inevitably masks the nanomaterial promising properties and compromises the time-stability in aqueous environments. The selective CVD growth of carbon nanomaterials was considered as a promising method to enable the coupling nanomaterial-electrode. Deposition parameters were optimised to make the process compatible with CMOS temperatures. Then, new protocols based on rapid electrodeposition methods were developed to integrate differently shaped and sized Pt and Pt-Au nanostructures on electrochemical platforms. Template-free electrodeposition was selected because of the durably-anchored and the contaminant-free coatings resulting after the process. Both nanostructuration approaches generated highly-sensitive electrodes to detect human metabolites as compared with the bare counterparts. Unprecedented sensing performance were obtained by both direct and enzyme-mediated detection mechanisms. Selective sensing was achieved thanks to the capability of the proposed nanostructured electrodes to discriminate the detection potentials of biomarkers from those of interfering species. The developed nanostructures were also excellent solid contacts between an electrode and an ion-selective membrane resulting in stable and reliable solid-contact ion-selective electrodes. To prove their stability and reproducibility for long operating lifetimes, these ion-selective electrodes have been successfully used as standard for continuous acute cell death monitoring

Present and future of surface-enhanced Raman scattering

The discovery of the enhancement of Raman scattering by molecules adsorbed on nanostructured metal surfaces is a landmark in the history of spectroscopic and analytical techniques. Significant experimental and theoretical effort has been directed toward understanding the surface-enhanced Raman scattering (SERS) effect and demonstrating its potential in various types of ultrasensitive sensing applications in a wide variety of fields. In the 45 years since its discovery, SERS has blossomed into a rich area of research and technology, but additional efforts are still needed before it can be routinely used analytically and in commercial products. In this Review, prominent authors from around the world joined together to summarize the state of the art in understanding and using SERS and to predict what can be expected in the near future in terms of research, applications, and technological development. This Review is dedicated to SERS pioneer and our coauthor, the late Prof. Richard Van Duyne, whom we lost during the preparation of this article

Applications of Multi-Terminal Memristive Devices: A Review

Memristive devices have the potential for a complete renewal of the electron devices landscape, including memory, logic and sensing applications. This is especially true when considering that the memristive functionality is not limited to two-terminal devices, whose practical realization has been demonstrated within a broad range of different technologies. For electron devices, the memristive functionality can be generally attributed to a state modification, whose dynamics can be engineered to target a specific application. In this review paper, we show examples of two-terminal Resistive RAMs (ReRAM) for standalone memory and Field Programmable Gate Arrays (FPGA) applications. Moreover, a Generic Memory Structure (GMS) utilizing two ReRAMs for 3D-FPGA is discussed. In addition, we show that trap charging dynamics can explain some of the memristive effects previously reported for Schottky-barrier field-effect Si nanowire transistors (SB SiNW FETs). Moreover, the SB SiNW FETs do show additional memristive functionality due to trap charging at the metal/semiconductor surface. The combination of these two memristive effects into multi-terminal MOSFET devices gives rise to new opportunities for both memory and logic applications as well as new sensors based on the physical mechanism that originate memristance. Finally, the multi-terminal memristive devices presented here have the potential of a very high integration density, and they are suitable for hybrid CMOS co-fabrication with a CMOS-compatible process

Sizing of Non-Carbonaceous Nanoparticles by Time-Resolved Laser-Induced Incandescence

Non-carbonaceous nanoparticles represent a growing field in science and technology. Their applications range from medicine to environmental remediation to information technology. As the functionality of nanoparticles in these roles is highly size dependent, it is critical that diagnostics be developed to accurately measure the size of these nanoparticles. Time-resolved laser-induced incandescence (TiRe-LII) is an in situ technique that can measure the size of nanoparticles without physically probing a system. The technique operates using a laser pulse that heats the nanoparticle to incandescent temperatures. The incandescence is then measured from the nanoparticles as they equilibrate with the surrounding gas. As smaller particles will cool more quickly, the size of the nanoparticles can be inferred by modeling the incandescence or, more commonly, the effective temperature decay of the nanoparticles. The present work summarizes attempts to extend the use of TiRe-LII from its original application on soot to non-carbonaceous particles. This will be done by examining experimental data from three non-carbonaceous nanoparticles: molybdenum, silicon, and iron. This includes descriptions of the TiRe-LII models and statistical techniques required to robustly infer parameters and their uncertainties. As one of the major setbacks in extending this technique to other materials is the determination of the thermal accommodation coefficient (TAC), this work also focusses on determining that parameter both from experimental data and molecular dynamics simulations