Production and mechanical characterization of graphene micro-ribbons

Patterning of graphene into micro- and nano-ribbons allows for the tunability in emerging fields such as flexible electronic and optoelectronic devices, and is gaining interest for the production of more efficient reinforcement for composite materials. In this work we fabricate micro-ribbons from CVD graphene by combining UV photolithography and dry etching oxygen plasma treatments. Raman spectral imaging confirms the effectiveness of the patterning procedure, which is suitable for large-area patterning of graphene on wafer-scale, and confirms that the quality of graphene remains unaltered. The produced micro-ribbons were finally transferred and embedded into a polymeric matrix and the mechanical response was investigated by in-situ mechanical investigation combining Raman spectroscopy and tensile/compressive tests

ZnO Nanostructure Templates as a Cost-Efficient Mass-Producible Route for the Development of Cellular Networks

The development of artificial surfaces which can regulate or trigger specific functions of living cells, and which are capable of inducing in vivo-like cell behaviors under in vitro conditions has been a long-sought goal over the past twenty years. In this work, an alternative, facile and cost-efficient method for mass-producible cellular templates is presented. The proposed methodology consists of a cost-efficient, two-step, all-wet technique capable of producing ZnO-based nanostructures on predefined patterns on a variety of substrates. ZnO—apart from the fact that it is a biocompatible material—was chosen because of its multifunctional nature which has rendered it a versatile material employed in a wide range of applications. Si, Si3N4, emulated microelectrode arrays and conventional glass cover slips were patterned at the micrometer scale and the patterns were filled with ZnO nanostructures. Using HeLa cells, we demonstrated that the fabricated nanotopographical features could promote guided cellular adhesion on the pre-defined micron-scale patterns only through nanomechanical cues without the need for further surface activation or modification. The basic steps of the micro/nanofabrication are presented and the results from the cell adhesion experiments are discussed, showing the potential of the suggested methodology for creating low-cost templates for engineered cellular networks

Rotating Triboelectric Nanogenerators for Energy Harvesting and Their Applications

Addressing the increasing development of IoT networks and the associated energy requirements, rotating triboelectric nanogenerators (R-TENGs) are proving to be strong candidates in the field of energy harvesting, as well as to that of self-powered devices and autonomous sensors. In this work, we review the theoretical framework surrounding the operating principles and key design parameters of R-TENGs, while also associating them with their output characteristics. Furthermore, we present an overview of the core designs used by the research community in energy harvesting applications, as well as variations of these designs along with explicit solutions for the engineering and optimization of the electrical output of R-TENGs. Last but not least, a comprehensive survey of the potential applications of R-TENGs outside the energy harvesting scope is provided, showcasing the working principles of the various designs and the benefits they confer for each specific scenario

STUDY OF THE OXIDATION OF SILICON AND THE INDUCED DEFECTS IN SILICON - ON - INSULATOR STRUCTURES

ΤΟ ΑΝΤΙΚΕΙΜΕΝΟ ΤΗΣ ΕΡΓΑΣΙΑΣ ΑΥΤΗΣ ΕΙΝΑΙ Η ΜΕΛΕΤΗ ΤΗΣ ΟΞΕΙΔΩΣΗΣ ΤΟΥ ΠΥΡΙΤΙΟΥ ΚΑΙΤΩΝ ΕΝΔΟΠΛΕΓΜΑΤΙΚΩΝ ΑΤΟΜΩΝ ΠΟΥ ΓΕΝΝΙΟΥΝΤΑΙ ΚΑΤΑ ΤΗΝ ΟΞΕΙΔΩΣΗ, ΚΑΘΩΣ ΚΑΙ ΟΙ ΜΗΧΑΝΙΣΜΟΙ ΠΟΥ ΚΑΘΟΡΙΖΟΥΝ ΤΗΝ ΚΑΤΑΝΟΜΗ ΤΩΝ ΕΝΔΟΠΛΕΓΜΑΤΙΚΩΝ ΑΤΟΜΩΝ ΣΕ ΜΙΑ ΚΑΙ ΔΥΟ ΔΙΑΣΤΑΣΕΙΣ, ΚΑΤΑ ΤΗΝ ΟΞΕΙΔΩΣΗ ΤΩΝ ΔΟΜΩΝ ΠΥΡΙΤΙΟΥ ΠΑΝΩ ΣΕ ΜΟΝΩΤΙΚΟ. ΑΝΑΠΤΥΣΣΟΝΤΑΙ ΠΡΩΤΥΠΑ ΠΕΙΡΑΜΑΤΑ, ΓΙΑ ΤΗΝ ΜΕΛΕΤΗ ΤΗΣ ΚΙΝΗΤΙΚΗΣ ΤΩΝ ΕΝΔΟΠΛΕΓΜΑΤΙΚΩΝ ΑΤΟΜΩΝ ΚΑΙ ΤΗΝ ΑΛΛΗΛΕΠΙΔΡΑΣΗ ΤΟΥΣ ΣΤΗ ΔΙΕΠΙΦΑΝΕΙΑ ΤΟΥ ΠΥΡΙΤΙΟΥ ΜΕ ΔΙΑΦΟΡΑ ΥΜΕΝΙΑ ΣΤΗ ΠΕΡΙΟΧΗ ΘΕΡΜΟΚΡΑΣΙΩΝ ΠΟΥ ΚΑΤΑΣΚΕΥΑΖΟΝΤΑΙ ΤΑ ΟΛΟΚΛΗΡΩΜΕΝΑ ΚΥΚΛΩΜΑΤΑ. ΕΠΙΣΗΣ ΕΞΕΤΑΖΟΝΤΑΙ ΟΙ ΕΠΙΠΤΩΣΕΙΣ ΤΗΣ 2 - ΔΙΑΣΤΑΤΗΣ ΚΑΤΑΝΟΜΗΣ ΤΩΝ ΣΗΜΕΙΑΚΩΝ ΑΤΕΛΕΙΩΝ ΣΤΗΝ ΛΕΙΤΟΥΡΓΙΑ ΤΩΝ ΗΛΕΚΤΡΙΚΩΝ ΔΙΑΤΑΞΕΩΝ.THE SUBJECT OF THIS WORK IS THE STUDY OF THE OXIDATION OF SILICON AND THE SILICON INTERSTITIAL THAT ARE GENERATED DURING OXIDATION AS WELL AS THE MECHANISMSTHAT DETERMINE THE DISTRIBUTION OF SILICON INTERSTITIAL IN 1D AND 2D DURING THE OXIDATION OF SILICON ON INSULATOR STRUCTURES. NEW EXPERIMENTS ARE DEVELOPED FOR THE STUDY OF SILICON INTERSTITIAL KINETICS AND THEIR INTERACTION AT THE INTERFACE OF SILICON WITH VARIOUS LAYERS, IN THE TEMPERATURE RANGE THAT IS USED FOR THE FABRICATION OF INTEGRATED CIRCUITS. WE ALSO INVESTIGATE THE INFLUENCE OF 2 - DIMENSIONAL DISTRIBUTION OF POINT DEFECTS ON THE OPERATION OF ELECTRICAL DEVICES

A Disposable Inkjet-Printed Humidity and Temperature Sensor Fabricated on Paper

In this work we present the development of a low-cost humidity and temperature sensing platform on paper by inkjet printing, using a commercial AgNPs conductive ink. The humidity sensing module was capable of measuring relative humidity in the range of 0⁻90%rH, exhibiting linear response with minimal memory effect when returning to 0%rH baseline signal while the temperature sensor performed linearly as well in the range of 25⁻75°C. Process repeatability has been verified by electrical and optical characterization. Mechanical bending results highlight the platform’s capability to serve as an easy to install, flexible multi-parametric sensing platform

Removal of a severely impacted mandibular third molar minimizing the risks of compromised periodontium, nerve injury, and mandibular fracture.

A technique is presented for severely impacted and dentigerous-cyst-related mandibular third molar removal, avoiding any associated risks. CASE PRESENTATION A healthy patient complained about unpleasant smell and taste in the mouth and unilateral extraoral palpation of a protuberance, at the right corner of the mandible. Restricted field CBCT showed a severely impacted third molar, which penetrated the inferior cortical bone of the mandibular corner and was associated with a dentigerous cyst that had resorbed considerable bone in the region. Surgical exposure of the impacted tooth and cyst marsupialization procedures under local anesthesia were combined with orthodontic extrusion of the impacted tooth to facilitate third molar removal. Treatment resulted in successful bone formation and safe tooth removal. The symptoms gradually improved after the first surgery and were eliminated by 14 months later, when the third molar was removed. Follow-up examination 1 year after removal showed favorable periodontal conditions. CONCLUSION Although it is not normally the first treatment of choice, orthodontically assisted impacted tooth removal is an alternative that can minimize the risk of compromised periodontium or injury to the adjacent tooth and the inferior alveolar nerve, as well as the risk of mandibular fracture, in complicated cases

Life Cycle Assessment and Preliminary Cost Evaluation of a Smart Packaging System

Smart food packaging (SP) is an innovative packaging system that can extend the shelf life of the product and reduce food waste. The objective of the study is the estimation of the environmental and economic sustainability of the overall life cycle of a SP including a chemical sensor able to detect modifications in the concentration of CO2, which is an indicator of food spoilage, and encapsulated oregano essential oil (OEO), capable of inhibiting the microbial growth. For this purpose, a life cycle assessment (LCA), following the ISO 14040 series and ReCiPe methodology, and an economic evaluation of SP, were performed. The environmental footprint (EF) of SP was compared to that of a conventional packaging (CP) in terms of packaging production, use and end of life (EoL) of both the packaging and the contained food product. The results demonstrated that the production of SP burdened by 67% the impact category of climate change. However, when adapting four use and EoL scenarios, namely the CP generates 30% food waste, whereas SP can generate 5% (optimistic scenario), 10% (realistic) or 20% (conservative) waste, SP proved to be environmentally superior in most impact categories

Influence of Carbon Quantum Dots on the Electrical Performance of Triboelectric Generators

In this work we investigate the triboelectric properties of Carbon Quantum Dots (CQDs) films for potential application in triboelectric generators. CQDs were deposited on silicon wafers, using spin on techniques. Device performance was estimated in sliding mode experiments, where the CQDs-surface was sliding on top of a flexible substrate. The triboelectric signal as well as the charging of capacitors, after signal rectification, was monitored as a function of time. Our results indicate that surface roughness plays a very important role in the triboelectric signal and could compensate opposite trends due to other parameters, such as the dielectric film thickness