Transmission medium and full fiber-optic setup for quantum key distribution applications

A fiber-optic-based coupled waveguide transmission medium is proposed to distribute secret keys in a single-photon polarization-based quantum cryptography setup. Polarization maintenance properties and coupling phenomena of the transmission medium are exploited to achieve accuracy and security of the transferred key. Elliptic fibers and fiber couplers are used to prepare the transmitted photons at the sender as well as analyze them at the receiver. The uniqueness of the setup stands on the exclusive use of fiber-optic components, enabling its construction on a single fiber line.     

Selection of indigenous Saccharomyces cerevisiae strains according to their oenological characteristics and vinification results

Xynomavro and Muscat Hamburg grapes were fermented spontaneously, producing red and white wine, respectively. The indigenous yeast flora, isolated at three phases of these fermentations, was studied. One hundred and ten strains were isolated, eighty-four of which were identified as Saccharomyces cerevisiae. Six of these strains were selected for their satisfactory oenological properties to be tested as starters in wine fermentations. The quality of the produced wines was evaluated after determination of their aromatic compounds and sensory analysis. S. cerevisiae strain BT4, as well as the AM4+BM3 combination, were considered the best as they produced wines characterized by fruity aromas and were highly accepted among panelists.     

Preparation of ZnO nanoparticles by thermal decomposition of zinc alginate

A new method to produce zinc oxide nanocrystals is presented. The method is based on the thermal decomposition of zinc alginate gels. The gels were produced in the form of beads by ionic gelation between a zinc solution and sodium alginate. The wet beads were heated at 800 and 450 °C for 24 h and the products were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission electron microscopy (TEM) and micro-Raman spectroscopy. XRD analysis showed that all obtained samples are of wurtzite structure. TEM analysis combined with electron diffraction also showed the presence of single crystals indexed as ZnO hexagonal phase. Crystal size was determined by measuring individual crystals from SEM pictures. It was found that heating temperature and the kind of zinc agent influence the crystal size. Raman scattering revealed the existence of defects in the structure of nanoparticles whose cringing was discussed in the context of recent studies in this field.     

Effect of chromium(VI) on bacterial kinetics of heterotrophic biomass of activated sludge

The effect of hexavalent chromium, Cr(VI), on the maximum specific growth rate, mu(m) and biomass yield, Y(H), of heterotrophic biomass was studied in batch tests conducted under high (= 10) and low (= 1.5) substrate-to-biomass ratios (S0/X0). The effects of sludge age and biomass acclimatization to Cr(VI) on the bacterial kinetics were also studied. The mu(m) values were determined by measuring oxygen uptake rate (OUR) and volatile suspended solids (VSS) increase. Cr(VI) concentrations equal or greater than 10 mg l(-1) inhibited the growth of unacclimatized activated sludge and caused a significant decrease in mu(m) and Y(H) values. The acclimatization of biomass and the selection of a high operating sludge age reduced the inhibitory effect of Cr(VI). At a sludge age of 20 days, Cr(VI) concentrations of <10 mg l(-1) stimulated bacterial growth as evidenced by an increase in both the mu(m) and Y(H) values. Determining mu(m) values by OUR and VSS methods, revealed that the presence of Cr(VI) in unacclimatized biomass caused an inhibitory effect mostly on substrate oxidation, while in acclimatized biomass, anabolic pathways were inhibited more.     

Assessment of practices and technologies of energy saving and renewable energy sources in hotels in Crete

This study aims to assess the state of the art of practices and technologies of energy saving and renewable energy sources in hotels. This will contribute to determining the potential of efficient and sustainable energy technologies integration. Hotel managers were interviewed face to face and information sessions were provided. Special energy and environmental awareness campaigns, sectoral tourism programs for climate change mitigation and adaptation, supportive policies and hotel energy investments and renovation programs are some recommendations elicited from the results of this study.     

A metric for quantifying the ripple effects among requirements

Software Quality Journal - During software maintenance, it is often costlier to identify and understand the artifacts that need to be changed, rather than to actually apply the change. In addition...     

HamDroid: permission-based harmful android anti-malware detection using neural networks

Neural Computing and Applications - Android platforms are a popular target for attackers, while many users around the world are victims of Android malwares threatening their private information....     

Announcement: Howard Rosenbrock Prize 2021

Optimization and Engineering -     

Oral Drug Delivery Systems Based on Ordered Mesoporous Silica Nanoparticles for Modulating the Release of Aprepitant

Two different types of ordered mesoporous nanoparticles, namely MCM-41 and MCM-48, with similar pore sizes but different pore connectivity, were loaded with aprepitant via a passive diffusion method. The percentage of the loaded active agent, along with the encapsulation efficiency, was evaluated using High-performance Liquid Chromatography (HPLC) analysis complemented by Thermogravimetric Analysis (TGA). The determination of the pore properties of the mesoporous particles before and after the drug loading revealed the presence of confined aprepitant in the pore structure of the particles, while Powder X-ray Diffractometry(pXRD), Differential Scanning Calorimetry (DSC), and FTIR experiments indicated that the drug is in an amorphous state. The release profiles of the drug from the two different mesoporous materials were studied in various release media and revealed an aprepitant release up to 45% when sink conditions are applied. The cytocompatibility of the silica nanoparticles was assessed in Caco-2 cell monolayers, in the presence and absence of the active agent, suggesting that they can be used as carriers of aprepitant without presenting any toxicity in vitro.