Wind Velocity Ebooks Catalog
Several methods exist for measuring ET from climatic data. The modified Penman and the Jensen-Haise methods use combinations of solar radiation, temperature, humidity, wind velocity and vapour pressure measurement to estimate ET for a reference crop. This then requires a crop coefficient to adjust the values obtained for the reference crop to estimate the ET of the crop to be irrigated. The crop coefficient values (ET of the irrigated crop ET of the reference crop) are multiplied by the ET values estimated by the specific method to estimate the ET of the irrigated crop.
Houses are not airtight, for air moves between the panes of glass as well as through closed ventilators and doors. Even in still conditions one to two air changes an hour can be expected, and more air changes will occur as wind speed rises over the glass area. The ideal screen is a filter rather than a windbreak and is about 60 per cent solid hedges and shrubs are good tor this purpose. An alternative is fine wire netting - a double fence of netting some 75 to 150 mm (3 to 6 111) apart provides the almost perfect filter, while cutting out little light. A fence of this sort may be well worth constructing if the greenhouse is being heated and keeping the temperature up, or at least regular, is important.
An experiment allows you to control your system so that your conclusions arc less ambiguous. To accomplish diis control, you must consider die factors that may affcct your phenomenon. We call these factors variables thev can be cither dependent or independent. The value of a dependent variable is determined by the value of an independent variable. For example, the distance traveled by milkweed seed may be dependent on the wind velocity, whereas the reverse is not true. In this ease, the distance is the dependent variable, and the wind velocity is the independent variable. In a controlled experiment, only one independent variable is allowed to changc, while the other independent variables are held constant. The investigator should rccognizc that additional variables may influence the dependent variable but may not be able to be controlled. Any uncontrolled variables should be rccognizcd, and if possible their potential impact should be minimized. Remember, though, that living systems...
Air temperatures and wind speed or lower humidity levels. As water evaporates from the surface, the water films on the soil particles become thinner. The surface tension forces in the film surface become proportionally greater as the water volume of the film decreases. This leaves water films on the particles at the surface with a high surface tension compared with those in the films on particles lower down in the soil. The increased suction gradient causes water to move slowly upwards to restore the equilibrium. Whilst the surface layers are kept moist by water moving slowly up from below, the losses by evaporation, in contrast, are quite rapid. Consequently the surface layers can become dry and the evaporation rate drops significantly after 5 to 10 'mm of water' is lost. Evaporation virtually ceases after the removal of 20 'mm of water' from the soil. Maintaining a dry layer on the soil surface helps conserve moisture in the soil below. Evaporation from the soil surface is almost...
Increasingly instrumentation is automated and, in protected culture, linked to computers programmed to maintain the desired environment by adjusting the ventilation and boiler settings. To achieve this, the computer is informed by external instruments measuring wind speed, air temperature and humidity, and internally by those measuring CO2 levels, ventilation settings, heating pipe temperature, air temperature and humidity.
Renewable Energy Eco Friendly
Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.