Experimental study of factors influencing the risk of drift from field sprayers Part 2: Spray application technique.

Recently, spray drift and its effects have become an important aspect of risk assessment in the registration process of pesticides in Belgium. In this regulation, drift reducing spray application techniques can be used to reduce buffer zones. The purpose of this research is to measure and compare the amount of drift sediment for different spray application techniques under field conditions. A drift prediction equation for the reference spraying was used to compare other spraying techniques with the reference spraying, under different weather conditions. Drift measurements were performed for several combinations of nozzle type (flat fan, low-drift, air injection) and size (ISO 02, 03, 04 and 06), spray pressure (2, 3 and 4 bar), driving speed (4, 6, 8 and 10 km.h-1) and spray boom height (0.3, 0.5 and 0.75 m). Nozzle type as well as spray pressure, driving speed and spray boom height, have an important effect on the amount of spray drift. Larger nozzle sizes, lower spray pressures and driving speeds and lower spray boom heights generally reduce spray drift. Concerning nozzle types, air injection nozzles have the highest drift reduction potential followed by the low-drift nozzles and the standard flat fan nozzles

The Capacity and Interference Statistics of High Car Traffic W-CDMA Street Cross-Shaped Micro-Cells (Uplink Analysis),

Since interference is related to the capacity and performance of W-CDMA system, it is necessary to investigate the interference characteristics (the mean value and the variance). Thus, the uplink capacity and the interference statistics of the sectors of the cross-shaped W-CDMA microcell have been analyzed using geometry with 17 microcells. A single slope propagation model with a lognormal shadowing factor has been used in the analysis. The cells have been assumed to exist in city streets with high car traffic. The capacity and the interference statistics of the sectors have been studied for different sector ranges, and different side-lobe level. The results show that the capacity increases with the increment of the sector range and with the reduction of the side-lobe level of the antennas used

FDSS Downlink Capacity in Urban Zone Near Digital Video Broadcasting Installations

The FDSS macrocell downlink capacity is evaluated for macrocells that operate at the same frequency of the Digital TV station (DTV) and that are nearby the DTV installations. It has been founded that the cell capacity is not affected when the distance between the DTV installations and the macrocell is more than 25 km. For lower distance, the effect is high and the downlink vanishes at a distance less than 2.1 km

The Performance of W-CDMA Highways Infostations

The expected value of the signal to noise ratio of W-CDMA infostations is derived. A model of 5 cells is used to analyze the system performance. The infostations are assumed to exist in rural zones. The performance of the infostations is studied for different breakpoint distances, different infostations separation, a different number of users for each infostation and for different bit rate

A New Quasi-Optimum Power Control Scheme for Downlink in W-CDMA Macro Cellular System

The downlink power control problem in W-CDMA is studied using a new proposed model. The downlink cell capacity is given for the old model given by Gejji and our new model. A capacity increase of 16 % for the special case = 0 (no orthogonality between users) and a generalization of the old model in terms of the propagation exponent and orthogonality factor is introduced

Experimental study of factors influencing the risk of drift from field sprayers, Part 1: Meteorological conditions

Spray drift can be defined as the quantity of plant protection product that is carried out of the sprayed (treated) area by the action of air currents during the application process. This continues to be a major problem in applying agricultural pesticides. The purpose of this research is to measure and compare the amount of drift for different climatological conditions under field conditions. Sedimenting spray drift was determined by sampling in a defined downwind area at different positions in a flat meadow using horizontal drift collectors for a reference spraying. Meteorological conditions were monitored during each experiment. A drift prediction equation for the reference spraying was set up to predict the expected magnitude of sedimenting at various drift distances and atmospheric conditions. The measurements proved the important effect of weather conditions (temperature, relative humidity and wind speed) on the amount of spray drift. A lower wind speed or a higher relative humidity decreases the amount of spray drift. Taking into account the correlation between temperature and relative humidity, a lower temperature will also result in lower drift values due to the cumulative effect of relative humidity. This equation can be used to quantify the effect of meteorological conditions, to compare measurements using other spraying techniques under different weather conditions to the reference spraying and to perform spray drift risk assessments

Carbon Sequestration Associated To The Land-use And Land-cover Changes In The Forestry Sector In Southern Brazil

We studied the Paraiba do Sul river watershed, Sao Paulo state (PSWSP), Southeastern Brazil, in order to assess the land use and cover (LULC) and their implications to the amount of carbon (C) stored in the forest cover between the years 1985 and 2015. The region covers an area of 1,395,975 ha. We used images made by the Operational Land Imager (OLI) sensor (OLI/Landsat-8) to produce mappings, and image segmentation techniques to produce vectors with homogeneous characteristics. The training samples and the samples used for classification and validation were collected from the segmented image. To quantify the C stocked in aboveground live biomass (AGLB), we used an indirect method and applied literature-based reference values. The recovery of 205,690 ha of a secondary Native Forest (NF) after 1985 sequestered 9.7 Tg (Teragram) of C. Considering the whole NF area (455,232 ha), the amount of C accumulated along the whole watershed was 35.5 Tg, and the whole Eucalyptus crop (EU) area (113,600 ha) sequestered 4.4 Tg of C. Thus, the total amount of C sequestered in the whole watershed (NF + EU) was 39.9 Tg of C or 145.6 Tg of CO2, and the NF areas were responsible for the largest C stock at the watershed (89%). Therefore, the increase of the NF cover contributes positively to the reduction of CO2 concentration in the atmosphere, and Reducing Emissions from Deforestation and Forest Degradation (REDD+) may become one of the most promising compensation mechanisms for the farmers who increased forest cover at their farms.9998EMBRAPAConference on Remote Sensing for Agriculture, Ecosystems, and Hydrology XVIIISEP 26-28, 2016Edinburgh, SCOTLAN

Modelling infiltration tests on pelletized bentonite under non-isothermal conditions

A promising alternative to construct engineered barriers for high level nuclear waste repositories is the use of pellets-based material because high dry densities can be achieved with no or minimal compaction effort. It is also planned to subject these materials to temperatures significantly higher than 100ºC. The paper reports the results of coupled THM analyses of a heating-hydration test performed on a granular assembly of MX-80 bentonite pellets. The goal is to characterize the material under conditions akin to those of an engineered barrier in a nuclear waste repository. It is shown that the numerical analyses are able to reproduce satisfactorily the observations of the test. This enhances the confidence placed on the computational tool for predicting the behaviour of actual engineered barriers constructed with pellets-based materials