Search results for "Charge"

Simplified hybrid PD model in voids: Pattern validation

2013

The purpose of the present work is to show the validation of a new model to simulate the physical phenomenon of partial discharge (PD) produced in air voids inside insulating epoxy resin. The model has been developed on the basis of a new approach that combines the known circuit model of three capacitors with a model used to describe the behavior of the ionized channel inside of the inclusion during the discharge phenomenon, short-circuiting the capacity that represents the void. The approach is based on time-variable conductance of the void, subjected to multistress conditions: voltage, temperature and pressure. The new approach has been developed from a time variable conductivity model us…

A Novel Histogram for Partial Discharge Signals in HV Insulating Systems

1986

A technique for relating measurable electrical quantities with energies dissipated inside a void in highly electrically stressed insulation is presented. It is based on measuring, for each apparent discharge level qe, the algebraic sum of the external energy pulses of all discharges having a value qe and occurring over some cycles of test voltage. Theoretical investigations show that the results of such external energy summations are equal to the energies dissipated in the void. A novel histogram is also suggested which relates the apparent discharge amplitudes with their respective energies in the void. Experimental tests were carried out under controlled conditions with samples of thermop…

Calibration of a knock prediction model for the combustion of a gasoline-natural gas mixture

2009

Gaseous fuels, such as Liquefied Petroleum Gas (LPG) and Natural Gas (NG), thank to their good mixing capabilities, allow complete and cleaner combustion than normal gasoline, resulting in lower pollutant emissions and particulate matter. Moreover natural gas, which is mainly constituted by methane, whose molecule has the highest hydrogen/carbon ratio, leads also to lower ozone depleting emissions. The authors in a previous work (1) experienced the simultaneous combustion of gasoline and natural gas in a bi-fuel S.I. engine, exploiting so the high knock resistance of methane to run the engine with an ‘overall stoichiometric’ mixture (thus lowering fuel consumption and emissions) and better …

International Legal Approaches to Waste Water Discharges. Opening speech

2002

En este discurso inaugural, realizo una introducción a la frustrante situación jurídica en la que se encuentran las descargas de aguas residuales a nivel internacional. Las descargas de aguas residuales son la mayor fuente de contaminación marina y, en consecuencia, ellas representan el mayor riesgo actual para la protección del medio ambiente marino. In this opening speech, I make an introduction to the disappointing legal situation of waste water discharges at international level. Waste water discharges is the main source of marine pollution and, therefore, they represent the major current risk to the protection of the marine environment.

New-stage discharge relationship for weirs of finite crest lenght

2014

AbstractThe flow process of weirs of finite crest length is analyzed on the basis of the dimensional analysis and incomplete self-similarity theory. The crest length is incorporated in the functional stage-discharge relationship for weirs of finite crest length. The theoretically deduced stage-discharge formula was then calibrated using the experimental data compiled in this research. According to the current experimental data it is also concluded that the performance of the proposed stage-discharge formula is better than the previous dimensional stage-discharge formulae. Also, the proposed stage-discharge formula is applicable for all types of the weirs, i.e., long-crested, broad-crested, …

Closure to “Theoretical End‐Depth‐Discharge Relationship for Free Overfall” by Vito Ferro

2000

Influence of Site and Check Dam Characteristics on Sediment Retention and Structure Conservation in a Mexican River

2020

Previously, in a large river of Mexico regulated by more than 200 check dams, we demonstrated that vegetation cover and channel characteristics were the dominant factors on the structure conditions and capacity to store sediments. This study focuses on other categorical (i.e., check dam type and location, soil texture and land use) and numerical (i.e. water discharge, check dam dimensions) variables, to whom statistical analysis is applied, in order to assess their influence on sediment filling degree and conditions (functional or destroyed) of the check dams in the same river. ANOVA has shown that: (i) check dam type (gabion or stone) and location (headwater, middle or valley reaches), and…

Climate change impact on SWAT simulated streamflow in western Kenya

2008

Weather and climate extremes such as droughts and floods have far reaching impacts in Kenya. They have had implications in a variety of sectors including agriculture, water resources, health, energy, and disaster management among others. Lake Victoria and its catchment support millions of people and any impact on its ability to support the livelihoods of the communities in this region is of major concern. Thus, the main objective of this study was to assess the potential future climatic changes on the Nzoia catchment in the Lake Victoria basin, and how they might affect streamflow. The Soil and Water Assessment Tool was used to investigate the impact of climatic change on streamflow of the …

Seasonal and Inter-annual Variation of Evapotranspiration in Amazonia Based on Precipitation, River Discharge and Gravity Anomaly Data

2019

We analyzed seasonal and spatial variations of evapotranspiration (ET) for five Amazon sub-basins and their response to the 2015/16 El Nino episode using a recently developed water-budget approach. ET varied typically between similar to 7 and 10 cm/month with exception of the Xingu basin for which it varied between 10 and 15 cm/month. Outstanding features of ET seasonality are (i) generally weak seasonality, (ii) two ET peaks for the two very wet catchments Solimoes and Negro, with one occurring during the wet season and one during the drier season, and (iii) a steady increase of ET during the second half of the dry season for the three drier catchments (Madeira, Tapajos, Xingu). Peak ET oc…

The foaming properties of camel and bovine whey: The impact of pH and heat treatment

2018

International audience; he effect of heat treatment (70 degrees C or 90 degrees C for 30 min) on the foaming and interfacial properties of acid and sweet whey obtained from bovine and camel fresh milk was examined. The maximum foamability and foam stability were observed for acid whey when compared to sweet whey for both milks, with higher values for the camel whey. This behavior for acid whey was explained by the proximity of the pI of whey protein (4.9-5.2), where proteins were found to carry the lowest negative charge as confirmed by the zeta potential measurements. Interfacial properties of acid camel whey and acid bovine whey were preserved at air water interface even after a heat trea…