Distributed parameters for low-frequency dielectric characterization of liquids with open-ended coaxial cell

The theory of distributed parameters is applied at low frequencies to the open-ended coaxial-line dielectric characterization technique. A procedure is proposed to determine the permittivity of liquids when the sample is placed between two dielectric beads to ensure tight closure. The technique leads to a complex transcendental equation that the authors solve. An ad hoc sample holder is built to implement the proposed method. Measurements of both polar and nonpolar liquids demonstrate the adequacy of the method and its advantages with respect to the lumped-circuit theory in the case of polar samples.     

A New Distribution System Reconfiguration Approach Using Optimum Power Flow and Sensitivity Analysis for Loss Reduction

This paper presents a new approach for distribution system reconfiguration (DSR) based on optimum power flow (OPF) in which the branch statuses (open/close) are represented by continuous functions. In the proposed approach, all branches are initially considered closed, and from the OPF results, a heuristic technique is used to determine the next loop to be broken by opening one switch. Then the list of switches that are candidates to be opened is updated, and the above process is repeated until all loops are broken, making the distribution system radial. This paper includes results and comparisons on test systems utilized in three classical papers published in the technical literature, as well as in a previous paper by the authors. Results obtained on a real large-scale distribution system are also presented     

Parallel Monte Carlo Driver (PMCD)—a software package for Monte Carlo simulations in parallel

Thanks to the dramatic decrease of computer costs and the no less dramatic increase in those same computer's capabilities and also thanks to the availability of specific free software and libraries that allow the set up of small parallel computation installations the scientific community is now in a position where parallel computation is within easy reach even to moderately budgeted research groups. The software package PMCD (Parallel Monte Carlo Driver) was developed to drive the Monte Carlo simulation of a wide range of user supplied models in parallel computation environments. The typical Monte Carlo simulation involves using a software implementation of a function to repeatedly generate function values. Typically these software implementations were developed for sequential runs. Our driver was developed to enable the run in parallel of the Monte Carlo simulation, with minimum changes to the original code that implements the function of interest to the researcher. In this communication we present the main goals and characteristics of our software, together with a simple study its expected performance. Monte Carlo simulations are informally classified as “embarrassingly parallel”, meaning that the gains in parallelizing a Monte Carlo run should be close to ideal, i.e. with speed ups close to linear. In this paper our simple study shows that without compromising the easiness of use and implementation, one can get performances very close to the ideal.     

A new approach to designing reduced scale thermal-hydraulic experiments

Reduced scale experiments are often employed in engineering because they are much cheaper than real scale testing. Unfortunately, though, it is difficult to design a thermal-hydraulic circuit or equipment in reduced scale capable of reproducing, both accurately and simultaneously, all the physical phenomena that occur in real scale and operating conditions. This paper presents a methodology to designing thermal-hydraulic experiments in reduced scale based on setting up a constrained optimization problem that is solved using genetic algorithms (GAs). In order to demonstrate the application of the methodology proposed, we performed some investigations in the design of a heater aimed to simulate the transport of heat and momentum in the core of a pressurized water reactor (PWR) at 100% of nominal power and non-accident operating conditions. The results obtained show that the proposed methodology is a promising approach for designing reduced scale experiments.     

A simulation analysis of the detectability of understory burns in miombo woodlands

The miombo woodlands of southern Africa are one of the most extensively burned biomes in the tropics. The detectability of understory burns in these woodlands was assessed with a sensitivity analysis approach, based on a hybrid geometrical-optical radiative transfer model. Model input data were obtained from a variety of sources, including field biometry and spectroradiometry, and satellite data. The effects of variable tree percent cover, leaf area index, stand density, burn scar age, illumination and observation geometry, and spectral region, were taken into account. Detectability of understory burns was defined as the spectral separability of burned and unburned understory, measured with the Jeffries-Matusita distance, for all possible combinations of the green, red, and near-infrared channels of the Moderate Resolution Imaging Spectrometer (MODIS) sensor. Single channels, or pairwise combinations of channels perform poorly at detecting understory burns, but a large improvement in detectability is obtained for the combination of the three spectral domains. The detectability of understory burns is largely insensitive to the effects of stand structure and illumination/observation geometry, and depends primarily on burn scar age. Our results agree with those of previous satellite-based studies of burns scar detectability in African savanna woodlands.     

Supported Pt-particles on multi-walled carbon nanotubes with controlled surface chemistry

Multi-walled carbon nanotubes (MWCNTs) were functionalized by HNO₃ hydrothermal oxidation at 200 °C. The degree of surface functionalization was described by an exponential function in terms of HNO₃ concentration. Very small Pt particles, with mean particle size of 1.7 ± 0.3 nm, could be supported on the surface of pristine MWCNTs and also on MWCNTs treated with HNO₃ concentrations up to 0.20 mol L^− 1, while a broader range of particle sizes, and larger Pt particles (3.4 ± 1.3 nm) were obtained on the MWCNTs treated with a higher HNO₃ concentration (0.30 mol L^− 1). Therefore, the amounts of surface groups and Pt particle sizes can be selected by tuning the HNO₃ concentration used in the hydrothermal treatment.     

Systematic Review: Drug Repositioning for Congenital Disorders of Glycosylation (CDG)

Advances in research have boosted therapy development for congenital disorders of glycosylation (CDG), a group of rare genetic disorders affecting protein and lipid glycosylation and glycosylphosphatidylinositol anchor biosynthesis. The (re)use of known drugs for novel medical purposes, known as drug repositioning, is growing for both common and rare disorders. The latest innovation concerns the rational search for repositioned molecules which also benefits from artificial intelligence (AI). Compared to traditional methods, drug repositioning accelerates the overall drug discovery process while saving costs. This is particularly valuable for rare diseases. AI tools have proven their worth in diagnosis, in disease classification and characterization, and ultimately in therapy discovery in rare diseases. The availability of biomarkers and reliable disease models is critical for research and development of new drugs, especially for rare and heterogeneous diseases such as CDG. This work reviews the literature related to repositioned drugs for CDG, discovered by serendipity or through a systemic approach. Recent advances in biomarkers and disease models are also outlined as well as stakeholders’ views on AI for therapy discovery in CDG.     

Effect of cavosurface angle beveling on the exposure angle of enamel prisms in different cavity sizes

The quality of the micromechanical retention between the enamel prisms exposed through acid etching and adhesive system can be influenced by the relationship between the angle of the exposed enamel prisms and the external surface/restorative material. Therefore, the aim of the present study was to determine the influence of the enamel cavosurface beveling in different cavity sizes on the angle relation between enamel prisms and the restorative material. For this research, 30 human permanent molars were used and divided into three groups according the isthmus aperture of class I cavities (1/4, 1/3, and 1/2 of the intercuspal distance). Cavosurface angle beveling was performed in each tooth buccal or palatal/lingual side, and a resin composite restoration was placed. Each restored tooth was sectioned in buccal/palatal direction followed by analysis in scanning electron microscope. Means of the angles observed between enamel prisms and the restorative material were registered and statistically analyzed by Kruskal‐Wallis test. Results showed higher mean angle values for beveled groups when comparing with the values observed in the unbeveled margins (p < .05) regardless of the isthmus aperture, being 1/4 (beveled = 48.36°; unbeveled = 20.71°), 1/3 (beveled = 39.75°; unbeveled = 29.15°), and 1/2 (beveled = 37.02°; unbeveled = 26.34°). It was also observed that in some unbeveled cavities, there were the presence of laterally exposed enamel prisms (0°), mainly in more conservative cavities. It was concluded that the presence of higher angles values occurred in the samples with beveled margins, without presence of laterally exposed enamel prisms.     

Recyclable,Flexible, Low‐Power Oxide Electronics

The ability to process and dimensionally scale field‐effect transistors with and on paper and to integrate them as a core component for low‐power‐consumption analog and digital circuits is demonstrated. Low‐temperature‐processed p‐ and n‐channel integrated oxide thin‐film transistors in the complementary metal oxide semiconductor (CMOS) inverter architecture are seamlessly layered on mechanically flexible, low‐cost, recyclable paper substrates. The possibility of building these circuits using low‐temperature processes opens the door to new applications ranging from smart labels and sensors on clothing and packaging to electronic displays printed on paper pages for use in newspapers, magazines, books, signs, and advertising billboards. Because the CMOS circuits reported constitute fundamental building blocks for analog and digital electronics, this development creates the potential to have flexible form factor computers seamlessly layered onto paper. The holistic approach of merging low‐power circuitry with a recyclable substrate is an important step towards greener electronics.     

Acoustic seafloor sediment classification using self-organizingfeature maps

A self-organizing feature map (SOFM), a kind of artificial neural network (ANN) architecture, is used in this work for continental shelf seafloor sediment classification. Echo data are acquired using an echosounding system from three types of seafloor sediment areas. Excellent classification (~100%) for an ideal output neuron grid size of 15×1 is obtained for a moving average of 35 input snapshots