Monte Carlo simulation of 2D TASER

A possibility to develop the so called TASER (Terahertz-Amplification-by-the-Stimulated-Emission-of- Radiation) by using two-dimensional (2D) electron transport in quantum well (QW) structures is investigated by Monte Carlo simulation of the optical-phonon-emission assisted transit-time resonance (OPTTR) of 2D electrons in momentum space under the low lattice temperature. A considerable extension of the frequency region for THz radiation generation (upto 5 times) when going from 3D- to 2D-case is predicted.     

Synthesis and Surface Properties Characterization of Perfluoroalkylated Oligo(oxyethylene)glycols

A series of perfluoroalkylated oligo(oxyethylene) glycols as non-ionic fluorinated surfactants was prepared. The synthesis was performed by adding a molecule of a oligo(oxyethylene)glycol of the general formula HO(CH₂CH₂O)_nOH (n = 1, 2, 4, 6.4, 22.3) to 2-(perfluorooctylmethyl) oxirane in the presence of catalytic amounts of a Lewis acid. This procedure led to the formation of an amphiphilic molecule characterized by an hydrophobic lipophobic perfluorinated tail and hydrophilic non-ionic oligo(oxyethylene)chain. Infra red spectroscopy, mass spectroscopy and multinuclear NMR spectroscopy allowed the chemical characterization of the synthesized compounds to be made. Critical micellar concentration, surface tension, interfacial tension and cloud point measurements carries out on aqueous solutions allowed us to evaluate the surface and interfacial properties of the perfluoroalkylated oligo(oxyethylene)glycols. In addition, surface pressure-area (π, A) diagrams allowed us to determine the principal parameters characterizing the state of their monolayers. The aim of the work was to investigate the effect of the hydrophilic chain length on physical and surface properties.     

Use of Bayesian Belief Networks when combining disparate sources of information in the safety assessment of software-based systems

The paper discusses how disparate sources of information can be combined in the safety assessment of software-based systems. The emphasis is put on an emerging methodology, relevant for intelligent product-support systems, to combine information about disparate evidences systematically based on Bayesian Belief Networks. The objective is to show the link between basic information and the confidence one can have in a system. How one combines the Bayesian Belief Net (BBN) method with a software safety standard (RTCA/DO-178B) for safety assessment of software-based systems is also discussed. Finally, the applicability of the BBN methodology and experiences from cooperative research work together with Kongsberg Defence & Aerospace and Det Norske Veritas, and ongoing research with VTT Automation are presented.     

Materials decay and environmental attack in the Pio Palace at Carpi: A holistic approach for historical architectural surfaces conservation

Since the XIV century the Pio Palace in Carpi (MO, Italy) has been subjected to many additions and rearrangements and, in the last decades, to wide restoration works. Nevertheless the XVII century main portal has not been restored yet, due to its complex and peculiar surface alteration forms in comparison with the other parts of the building, and still suffers a deep decay and degradation by complex chemical-physical processes.     

Diameter-Controlled Synthesis of Polyaniline Nanofibers

Summary  Various diameters of polyaniline (PANI) nanofibers were easily made by varying the sweep rate in the electrochemical polymerization of the aniline monomer. At a sweep rate of 5 mV/s, the PANI nanofibers have an average diameter of 450 nm with a median of 440 nm. The fibers are short, on the order of a few microns in length, and exhibit a branched geometry. Increasing the sweep rate to 50 mV/s produced longer nanofibers with a smaller average diameter of 200 nm. Nanofibers synthesized at 100 mV/s were noted to be smaller with an average and median diameter of 100 nm. These results illustrate the ease in which the morphology of nanostructured PANI can be altered and indicate that the method has the potential to create multi-diameter fibers or mixed-morphology materials.     

Synthesis and characterization of new injectable and degradable dextran-based hydrogels

Injectable and degradable hydrogels are very interesting networks for drug delivery and cell transplantation applications since they can be administered in the human body in a minimally invasive way. In most cases, the crosslinking reaction occurs by photopolymerisation or free radical polymerisation; however, the use of chemical initiators may promote cell death. In the current work, injectable and degradable dextran-based hydrogels were prepared without the use of initiators. Dextran, a natural glucose-containing polysaccharide, was oxidized with sodium periodate (dexOx) and the derivatives characterized by NMR and FTIR spectroscopy's as well as by colorimetric techniques. The oxidized derivatives were crosslinked with adipic acid dihydrazide (AAD), forming a gel within 2-4 min. The obtained hydrogels were characterized by their mechanical properties, swelling and degradation behavior under physiologic conditions. In addition, the hydrogel interior morphology as well as porous structure was evaluated by scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP). MIP analysis showed that dexOx hydrogels crosslinked with 10% of AAD were macroporous with pore sizes ranging from 0.32 to 0.08 μm. As expected, the average pore size increased during hydrogel degradation as confirmed by SEM and MIP studies.     

A road map to find in 3D printing a new design plasticity for construction — The state of art

Recent years are showing a rapid adoption of digital manufacturing techniques to the construction industry, with a focus on additive manufacturing. Although 3D printing for construction (3DPC) has notably advanced in recent years, publications on the subject are recent and date a growth in 2019, indicating that it is a promising technology as it enables greater efficiency with fair consumption of material, minimization of waste generation, encouraging the construction industrialization and enhancing and accelerating the constructive process. This new building system not only gives an optimization of the building process but provides a new approach to the building design materiality. The direct connection between design and manufacturing allows the reduction in the number of the various construction phases needed. It is opening a new and wide range of options both formal and chromatic in customization, avoiding complex formworks, reducing costs and manufacturing time. The creative process has a strict and direct link with the constructive process, straightening design with its materiality. Cement-based materials lead the way, but new alternatives are being explored to further reduce its carbon footprint. In order to leverage its sustainability and enhance the system capacity, initiatives are being pursued to allow the reduction of the use of PC. Geopolimers are taking the first steps in 3DPC. Construction and Demolition Waste (CDW) materials are used to substitute natural aggregates. Even soil is being explored has a structural and aesthetic material. These research trends are opening a wider range of possibilities for architecture and design, broadening the spectrum of color, texture, and formal variations. The concern about textures and colours is not yet evident in many the structures already printed, opening the opportunity for future research. More can be done in the mixture and formal design of this building system, “discovering” other raw materials in others waste. This article aims to make a critical review of technologies, materials and methodologies to support the development of new sustainable materials to be used as a plastic element in the printed structure. A roadmap of 3D printing for construction is presented, and an approach on mix design, properties in the fresh and hardened state, highlighting the possibilities for obtaining alternative materials are pointed. With this review possible directions are presented to find solutions to enhance the sustainability of this system discovering “new” materiality for architecture and design.     

Effects from log-yard stormwater runoff on the microalgae Scenedesmus subspicatus: intra-storm magnitude and variability

This paper describes the effects posed by stormwater runoff from an industrial log-yard on the microalgae Scenedesmus subspicatus. The effects of stormwater runoff sampled during two rain events were determined by exposing S. subspicatus cells to different concentrations (% v:v) of each sample. The effects were measured as the percentage change in growth rates in relation to a control culture after exposure times of 24, 48, 72 and 96 h. The runoff from the first rain event had no negative effects to S. subspicatus, posing in most cases growth stimulation, whereas the runoff from the second rain event inhibited algae growth. Differences in runoff physico-chemical characteristics combined with the hydrological factors of each rain event explained these opposite effects. The hypothesis of toxic first flush phenomenon was confirmed in the second rain event on the basis of normalized inhibitory effects and runoff volume. It was found that 42, 51 and 50% of the inhibitory effects during exposures of 24, 48 and 72 h were associated with the initial 4% of the total discharged volume. The fact that negative effects were observed in the two runoff events analyzed, raises concern about the potential environmental threats posed by runoff originated from wood-based industrial areas during the entire hydrological year.     

IEEE Power & Energy Magazine for Electric Power Professionals New Magazine Announcement and Call for Articles

Administrative and regulatory authorities, politicians, utilities and consumers have tried to understand the underlying reasons for the crisis and extract pertinent lessons for Spain. The Spanish situation following the California crisis, as well as the major topics, are examined in this article. Significant similarities and differences with the Spanish system are evaluated.     

Survey of caffeine levels in retail beverages in Portugal.

The caffeine content of 85 retail beverage samples purchased from local supermarkets between 1995 and 2004 was determined. The potential intake of caffeine through the consumption of these beverages (but excluding coffee) was estimated for students of the University of Coimbra, Portugal. The caffeine content of the beverages ranged from 47.5 to 282.5 mg l(-1) for teas, from 20.1 to 47.2 mg l(-1) for tea extracts samples, and from 80.7 to 168.7 mg l(-1) for cola soft drinks. Caffeine was not completely absent from caffeine-free colas, and energy drinks had a far greater caffeine content than regular drinks, ranging from 21 to 2175 mg l(-1). Soft drinks were consumed by 72% of the individuals, although 14% of the survey participants did not drink any of the different types of the beverages studied. Contrary to expectations for this age group, no consumptions of energy drinks was reported. Daily caffeine intake was estimated to range from 4.7 to 200 mg day(-1), but with only 5% reporting a daily intake around 200 mg caffeine. Cola-type beverages were an important dietary source of caffeine for the population studied. Statistical differences in the caffeine intake between the male and female populations were found, with p = 0.014, being higher for the male population. Of the beverages studied, cola-type drinks showed statistical differences for the male population, p = 0.03, and tea showed statistical differences for female population p = 0.013, respectively.