Evaluation of the potential for power line carrier (PLC) tointerfere with use of the Nationwide Differential GPS network

Power line carrier (PLC) is an important technique used extensively on electric power lines for communication and telemetry. PLC uses signals in the 40-490 kHz range that couple to and propagate over power line conductors. Applications of PLC include protective relaying, telemetering, voice communications, supervisory control, etc. The new Nationwide Differential Global Positioning System (NDGPS) network uses the 283.5-325 kHz band to broadcast GPS correction messages throughout the world, and some PLC transmitters may operate in this band. Limited work has been done to either measure or model the electromagnetic fields associated with PLC operation and some of these studies demonstrate the potential for PLC fields close to power lines to degrade navigation signal receiver performance. This paper presents PLC field strength measurements, describes NDGPS signal structure, and recommends frequency separation as the best approach to mitigation for potential PLC interference to NDGPS receivers operated near to power lines     

NUMERICAL SIMULATION OF DRYING IN A CYCLONE

This work presents a complete improved mathematical model of drying in cyclone. The slip condition of the particles on the wall, the heat transfer wall-panicle and the shrinkage of the panicles during the drying process were considered. The mathematical model considers a two-dimensional turbulent gas-particle flow where the panicle phase is treated as a continuum. The momentum equations of both particle and gas phases were written in cylindrical coordinates. The discretized equations were solved by the SIMPLE algorithm. Considering the slip condition to the panicle phase and the shrinkage of the material during the drying process it was revealed a better fitness between numerical and experimental results than the previous model.     

Development of a Thin Film Magnetic Moment Reference Material

In this paper we present the development of a magnetic moment reference material for low moment magnetic samples. We first conducted an inter-laboratory comparison to determine the most useful sample dimensions and magnetic properties for common instruments such as vibrating sample magnetometers (VSM), SQUIDs, and alternating gradient field magnetometers. The samples were fabricated and then measured using a vibrating sample magnetometer. Their magnetic moments were calibrated by tracing back to the NIST YIG sphere, SRM 2853.     

Acute ingestion of yerba mate infusion (Ilex paraguariensis) inhibits plasma and lipoprotein oxidation

Yerba mate extract (Ilex paraguariensis) is a source of phenolic compounds that possesses in vitro antioxidant activities and may contribute to a reduction in the risk of cardiovascular disease. In this study we examined the acute effects of the consumption of mate infusion on ex vivo plasma and low-density lipoprotein (LDL) oxidation, plasma antioxidant capacity, and platelet aggregation. Twelve healthy fasted subjects ingested 500 mL of mate infusion and blood samples were collected before and 1 h after mate intake. Lipid peroxidation of plasma and LDL was monitored by the measurement of cholesteryl-ester hydroperoxides (CE-OOH) and cholesterol oxides. The plasma antioxidant capacity was measured as ferric-reducing antioxidant potential (FRAP). Platelet aggregation was evaluated in platelet-rich plasma stimulated with adenosine diphosphate and coagulation was tested in platelet-poor plasma. Ingestion of mate infusion diminished the ex vivo oxidizability of both plasma and LDL particles. After mate intake, the CE-OOH levels were around 50% lower in plasma oxidized with copper or 2,2′-azobis[2-amidine-propane-hydrochloride] (AAPH) and the lag time to plasma oxidation increased 2-fold (P < 0.05). Copper- and AAPH-induced LDL peroxidation were also inhibited by around 50% and 20%, respectively, after mate consumption (P < 0.05). The levels of various oxysterols were significantly reduced in oxidized-plasma and LDL (P < 0.05) and FRAP increased by 7.7% after mate intake (P < 0.01). However, mate consumption did not inhibit platelet aggregation or blood coagulation. In summary, intake of yerba mate infusion improved the antioxidant capacity and the resistance of plasma and LDL particles to ex vivo lipid peroxidation.     

Distribution of transposable elements in neotropical species of Drosophila

The phylogenetic distribution of transposable families, P, gypsy, hobo, I, and mariner has been analyzed in 33 species of 11 groups of neotropical Drosophila and a Drosophilidae species Zygotrica vittimaculosa, using squash blot and dot blot. Genomic DNA of almost all neotropical species tested hybridized with gypsy probe and some species showed a particularly strong hybridization signal, as D. gaucha, D. virilis, and species of flavopilosa group. The hobo element was restricted to melanogaster group and some strains of D. willistoni. Only D. simulans DNA showed hybridization to mariner probe in all species tested and D. simulans and D. melanogaster showed hybridization with I element probe. P element homologous sequence was present in D. melanogaster and all species and strains of the willistoni and saltans groups tested. The presence of at least one P-homologous sequence was detected in Drosophila mediopunctata. This one was the only P-bearing species of all six tested from the tripunctata group. Four different pairs of primers homologous to segments of the canonical sequence of D. melanogaster's P were used to amplify specific sequences from D. mediopunctata DNA, showing the occurrence of seemingly well-conserved P-homologous sequences.     

Multi-approach back-analysis of a roof bed collapse in a mining room excavated in stratified rock

Roof bed deformation mechanics is a complex topic in mining practice. There are a number of empirical, analytical and numerical techniques that can be used to analyze and design underground excavations in stratified rock masses. Each has particular drawbacks, however, so the use of just one approach in order to obtain consistent and economic designs is not practical. To deepen understanding of this topic, it is useful to study real failure in mines. In this paper we describe how a roof bed failure in an underground mine, excavated in a stratified rock mass, was back-analyzed using different approaches, namely, the empirical stability graph method, the analytical voussoir techniques, and the numerical discrete element method. The study enabled us to better understand the conditions of failure and to define the most significant parameters affecting the failure. It has also been shown how relaxation or loss of confinement stress can play an important role in roof bed deformation.     

The use of curvature and bias measures to discriminate among equilibrium moisture equations for mustard seed

The aim of this work was to analyze the main equilibrium equations used for grains to find the best way to represent the equilibrium conditions between mustard seed and air. The experimental study was based on the static method using saturated salt solutions to regulate the vapor pressure of the air surrounding the seeds. Since the majority of the sorption equilibrium equations are nonlinear, procedures available in the literature were used to validate the statistical properties of the least squares estimators. To discriminate, between five equations that represent the sorption equilibrium isotherms of mustard seeds, an approach based on nonlinear measures was used in this work. Results show that the Halsey modified equation is the best one to describe the experimental data.     

A Novel Approach to Detect Faults Occurring During Power Swings by Abrupt Change of Impedance Trajectory

The main purpose of power swing blocking is to distinguish faults from power swings. However, faults occurred during a power swing should still be detected and cleared promptly. This paper proposes an index based on detecting abrupt jump of impedance trajectory by utilization of the predicting capability of the Kalman Filter. The proposed index is calculated by assessing the difference between predicted and actual samples of impedance. The predicted impedance samples are obtained using the Kalman filter and Taylor expansion, which are used in this paper to track the phasor precisely. Second order of Taylor expansion is used to decrease the corrugation effect of impedance estimation and increase the reliability of the proposed method. Furthermore, in order to increase the selectivity of the proposed method, the proposed index is armed with phase comparison logic to detect internal faults. The instantaneous estimation and prediction capability of the Kalman filter are two reasons for proposing the use of Kalman filter. Intensive studies have been performed and the merit of the method is demonstrated by test simulations.     

Nitrous oxide emission and ammonia volatilization induced by vinasse and N fertilizer application in a sugarcane crop at Rio de Janeiro,Brazil

In Brazilian sugarcane plantations, fertilization with vinasse, supplemented or not with mineral fertilizer, is a common practice. But little is known about the effects of this application on N losses, especially those forms of N which give rise to greenhouse gas emissions. The aim of this study was to quantify N₂O and NH₃ emissions from soil after vinasse application and urea fertilizer addition and to examine the possible impact adding vinasse before or after urea. Two experiments were conducted under greenhouse conditions and one in the field with treatments of vinasse and urea fertilizer, either alone, or in sequence. The highest proportions of N emitted as N₂O were registered in the vinasse treatment, which amounted to 15 % of the N applied in the first greenhouse experiment, and 2.5 % in the field experiment. With respect to the losses by NH₃ volatilization, urea was the only treatment where this process was significant. N₂O emission from vinasse was 2.5 %, somewhat above the default emission factor of 1 % of the IPCC. N₂O emissions from urea were also variable, but emission factors registered were still well below the default IPCC factor for organic residues. The order of addition of urea and vinasse had little effect on NH₃ volatilization in the field, but there were evidences it was important for N₂O.     

Biosurfactant-and-Bioemulsifier Produced by a Promising Cunninghamella echinulata Isolated from Caatinga Soil in the Northeast of Brazil

A Mucoralean fungus was isolated from Caatinga soil of Pernambuco, Northeast of Brazil, and was identified as Cunninghamella echinulata by morphological, physiological, and biochemical tests. This strain was evaluated for biosurfactant/bioemulsifier production using soybean oil waste (SOW) and corn steep liquor (CSL) as substrates, added to basic saline solution, by measuring surface tension and emulsifier index and activity. The best results showed the surface water tension was reduced from 72 to 36 mN/m, and an emulsification index (E₂₄) of 80% was obtained using engine oil and burnt engine oil, respectively. A new molecule of biosurfactant showed an anionic charge and a polymeric chemical composition consisting of lipids (40.0% w/w), carbohydrates (35.2% w/w) and protein (20.3% w/w). In addition, the biosurfactant solution (1%) demonstrated its ability for an oil displacement area (ODA) of 37.36 cm², which is quite similar to that for Triton X-100 (38.46 cm²). The stability of the reduction in the surface water tension as well as of the emulsifier index proved to be stable over a wide range of temperatures, in pH, and in salt concentration (4%–6% w/v). The biosurfactant showed an ability to reduce and increase the viscosity of hydrophobic substrates and their molecules, suggesting that it is a suitable candidate for mediated enhanced oil recovery. At the same time, these studies indicate that renewable, relatively inexpensive and easily available resources can be used for important biotechnological processes.