On the Creation of Sustainable Design Patterns of ICT Integration in the Classroom

The paper focuses on the methodology of making observations that account for the actual use of ICT infrastructure and tools in the classroom. The observational study is part of a project that focuses on scenario feasibility as an enabler of ICT usage. In particular, the observations provide input on pattern mining with the aim to help teachers and other stakeholders in the decision-making process of selecting suitable ICT facilities

Graphene oxide dielectric permittivity at GHz and its applications for wireless humidity sensing

Graphene oxide relative dielectric permittivity, both its real and imaginary parts, have been measured under various humidity conditions at GHz. It is demonstrated that the relative dielectric permittivity increases with increasing humidity due to water uptake. This electrical property of graphene oxide was used to create a battery-free wireless radio-frequency identification (RFID) humidity sensor by coating printed graphene antenna with the graphene oxide layer. The resonance frequency as well as the backscattering phase of such graphene oxide/graphene antenna become sensitive to the surrounding humidity and can be detected by the RFID reader. This enables batteryless wireless monitoring of the local humidity with digital identification attached to any location or item and paves the way for low-cost efficient sensors for Internet of Things applications

Exfoliation of natural van der Waals heterostructures to a single unit cell thickness

Weak interlayer interactions in van der Waals crystals facilitate their mechanical exfoliation to monolayer and few-layer two-dimensional materials, which often exhibit striking physical phenomena absent in their bulk form. Here we utilize mechanical exfoliation to produce a two-dimensional form of a mineral franckeite and show that the phase segregation of chemical species into discrete layers at the sub-nanometre scale facilitates franckeite's layered structure and basal cleavage down to a single unit cell thickness. This behaviour is likely to be common in a wider family of complex minerals and could be exploited for a single-step synthesis of van der Waals heterostructures, as an alternative to artificial stacking of individual two-dimensional crystals. We demonstrate p-type electrical conductivity and remarkable electrochemical properties of the exfoliated crystals, showing promise for a range of applications, and use the density functional theory calculations of franckeite's electronic band structure to rationalize the experimental results

Vertical Field Effect Transistor based on Graphene-WS2 Heterostructures for flexible and transparent electronics

The celebrated electronic properties of graphene have opened way for materials just one-atom-thick to be used in the post-silicon electronic era. An important milestone was the creation of heterostructures based on graphene and other two-dimensional (2D) crystals, which can be assembled in 3D stacks with atomic layer precision. These layered structures have already led to a range of fascinating physical phenomena, and also have been used in demonstrating a prototype field effect tunnelling transistor - a candidate for post-CMOS technology. The range of possible materials which could be incorporated into such stacks is very large. Indeed, there are many other materials where layers are linked by weak van der Waals forces, which can be exfoliated and combined together to create novel highly-tailored heterostructures. Here we describe a new generation of field effect vertical tunnelling transistors where 2D tungsten disulphide serves as an atomically thin barrier between two layers of either mechanically exfoliated or CVD-grown graphene. Our devices have unprecedented current modulation exceeding one million at room temperature and can also operate on transparent and flexible substrates

Raman spectroscopy of graphene and bilayer under biaxial strain: bubbles and balloons

In this letter we use graphene bubbles to study the Raman spectrum of graphene under biaxial (e.g. isotropic) strain. Our Gruneisen parameters are in excellent agreement with the theoretical values. Discrepancy in the previously reported values is attributed to the interaction of graphene with the substrate. Bilayer balloons (intentionally pressurized membranes) have been used to avoid the effect of the substrate and to study the dependence of strain on the inter-layer interactions.Comment: 14 pages, 4 figure

Electron transfer kinetics on natural crystals of MoS2 and graphite

Here, we evaluate the electrochemical performance of sparsely studied natural crystals of molybdenite and graphite, which have increasingly been used for fabrication of next generation monolayer molybdenum disulphide and graphene energy storage devices. Heterogeneous electron transfer kinetics of several redox mediators, including Fe(CN)63−/4−, Ru(NH3)63+/2+ and IrCl62−/3− are determined using voltammetry in a micro-droplet cell. The kinetics on both materials are studied as a function of surface defectiveness, surface ageing, applied potential and illumination. We find that the basal planes of both natural MoS2 and graphite show significant electroactivity, but a large decrease in electron transfer kinetics is observed on atmosphere-aged surfaces in comparison to in situ freshly cleaved surfaces of both materials. This is attributed to surface oxidation and adsorption of airborne contaminants at the surface exposed to an ambient environment. In contrast to semimetallic graphite, the electrode kinetics on semiconducting MoS2 are strongly dependent on the surface illumination and applied potential. Furthermore, while visibly present defects/cracks do not significantly affect the response of graphite, the kinetics on MoS2 systematically accelerate with small increase in disorder. These findings have direct implications for use of MoS2 and graphene/graphite as electrode materials in electrochemistry-related applications

NOA-ReACT/PollyXT-SCC-Pipelines: v1.14.3

<h2>What's new since 1.14.2</h2> <p>Changed sunset time for Antikythera to 16:00. No other changes in this version.</p> <h2>What's new since 1.14.1</h2> <p>Fixed a small compatibility issue with the SCC API. Also marked as compatible with Python 3.11, this should fix any installation compatibility issues.</p> <h2>What's new since 1.14.0</h2> <p>The program now supports SCC's new <code>channel_string_IDs</code> variable, which allows the user to use channel names instead of the system integer IDs. This can be enabled by using names instead of numbers at the appropriate (e.g. <code>channel_id</code>) inside <code>locations.ini</code>.</p> <h2>What's new since 1.13</h2> <p>This release adds support for adjusting the sunrise and sunset times that are used for determining the configuration ID. Specifically, there are two new location options (<code>sunrise_time</code> and <code>sunset_time</code>) that can be set either to a fixed time (HH:MM) or a minute offset (e.g., +12 or -34).</p> <h2>How to upgrade</h2> <p>You can always upgrade to the latest version by running:</p> <pre><code>pip install pollyxt-pipelines --upgrade </code></pre> <h2>Changes since 1.14.2</h2> <ul> <li> Change sunset time for Antikythera to 16:00</li> </ul&gt

Microbial Biodiversity of Posidonia oceanica meadows of Cyprus. A literature review on microbial community investigation

Posidonia oceanica is the most common, widespread and important seagrass in the Mediterranean basin, and hosts a large biodiversity of species, including microorganisms such as bacteria and fungi which play a key role in the marine environment. In this study, a first approach was made in order to determine the microbial diversity of the seagrass Posidonia oceanica, which is a seriously threatened Mediterranean species in Cyprus. These microorganisms should be exploited further in biotechnology and investigate their role and uses. The findings of this study revealed that the bacteria genera found in P. oceanica were Vibrio, Pseudovibrio, Pseudoalteromonas and Labrenzia. The predominant genus was found to be Vibrio in the three sampling locations (Limassol, Vassilikos, and Cavo Greco). Furthermore, the study shows that the predominant genus of fungi was Cladosporium, followed by Aspergillus, Penicillium and Stamphylium. The fungal species which were identified were, Stemphylium vesicarium, Cladosporium cladosporioides, Cladosporium herbarum, Penicillium chrysogenum, Aspergillus tubingensis, Cladosporium sphaerospermum, Penicillium brevicompactum, Aspergillus niger, Davidiella tassiana, Cladosporium macrocarpum and Stemphylium vesicarium. Cultured-based methods are important in investigating the microbial ecology and natural environments, but they are extremely biased in their evaluation of microbial genetic diversity by selecting a particular population of microorganisms. In the framework of this study was to represent a variety of molecular approaches based on direct isolation and analysis of nucleic acids and proteins from environmental studies such as genetic fingerprinting, metagenomics and metaproteomics. This study represents the current molecular approaches used in microbial ecology.Complete

Photoelectrochemistry of Pristine Mono- and Few-Layer MoS₂

Two-dimensional crystals are promising building blocks for the new generation of energy materials due to their low volume, high surface area, and high transparency. Electrochemical behavior of these crystals determines their performance in applications such as energy storage/conversion, sensing, and catalysis. Nevertheless, the electrochemistry of an isolated monolayer of molybdenum disulfide, which is one of the most promising semiconducting crystals, has not been achieved to date. We report here on photoelectrochemical properties of pristine monolayer and few-layer basal plane MoS₂, namely the electron transfer kinetics and electric double-layer capacitance, supported by an extensive physical and chemical characterization. This enables a comparative qualitative correlation among the electrochemical data, MoS₂ structure, and external illumination, although the absolute magnitudes of the electron transfer and capacitance are specific to the redox mediator and electrolyte used in these measurements ([Ru­(NH₃)₆]^3+/2+ and LiCl, respectively). Our work shows a strong dependence of the electrochemical properties on the number of MoS₂ layers and illumination intensity and proves that an effective interlayer charge transport occurs in bulk MoS₂. This highlights the exciting opportunities for tuning of the electrochemical performance of MoS₂ through modification of its structure, external environment, and illumination