Hail impact

The wind turbine rotor blades, both for on-shore and off-shore wind farms, are exposed to various hostile conditions such as extreme temperatures, humidity, rain, hail impact, snow, ice, solar radiation, lightning and salinity. In order to withstand these external conditions without diminishing safety, a sound knowledge of the fatigue behaviour of the material and structural properties is needed. 

Polycarbonate (see Section 5.2.2.3) is used in applications similar to those of polymethyl methacrylate and is always used when high toughness, e.g., hail impact resistance and/or increased heat resistance are required. Other than PMMA, polycarbonate has to be protected for outdoor applications in order to meet outdoor service life expectations by the customer, e.g., in building construction. Figure 5.63 [68]. 

Injury to plants and vegetation is caused by a variety of factors, of which air pollution is only one. Drought, too much water, heat and cold, hail, insects, animals, disease, and poor soil conditions are some of the other causes of plant injury and possible plant damage (3). Estimates suggest that less than 5% of total crop losses are related to air pollution. Air pollution has a much greater impact on some geographic areas and crops than others. Crop failure can be caused by fumigation from a local air pollution source or by more widespread and more frequent exposure to adverse levels of pollution. 

Ice and hail, snow, etc. can cause a loss of off-site power. The reactor building was designed to withstand blast pressure of 1,000 Ibs/ft can withstand tornado missile impact (Sharp, 1986). A tornado could damage the reactor by hitting the river water pump houses similar to the flooding scenario. 

The contribution of atmospheric dust to surface dust depends on the dust falling to the earth. This occurs either as dry dust fall or wet washout with rain, snow or hail (1-6,8-10). Dry dust fall occurs by s imentation, impaction, interception or diffusion. Sedimentation, the fall under gravity, may be estimated using Stoke s law which relates the density and diameter of particles to their falling velocity. A particle of density 1.0 g cm"3 and diameter around 0.1 pm would fall with a velocity of around 9 x 10" cm s" ... 

Most pharmaceutical companies have research programs in genomics/proteomics. The omics revolution was initially hailed as a revolution in drug discovery. While these modern technologies may well help identify a host of putative new biopharmaceuticals (see also Part I, Chapters 4 and 5), they almost certainly will have a far more significant impact upon identifying... 

The goal of the backsheet is to provide UV and moisture protection, electrical insulation, and durability. To this purpose, standard international committees (such as lEC and UL) have defined a set of tests to be passed before a photovoltaic s module could be placed on the market. The lEC 61215 is one of the most used standards for qualifying a PV module [7]. The aim of these tests is to check the resistance of the PV module to all the variables that can affect and infiuence the life of the module itself such as electrical performance, hail and impact test, weathering, and temperature (UV and thermal cycling). One of the most important tests is the damp heat test, 1000 hours inside a climatic chamber at 85°C and 85% relative humidity. Most of the PV module producers tend to prolong well above 1000 hours of damp heat, to be sure that the module will survive after 25 years giving at least 80% of the initial power. This trend is also taken into consideration into the new version of the standard tests that is considering to have at least 2000 hours of damp heat for qualification. 

Weather modification has traditionally had two components, planned and inadvertent. Planned weather modification refers to cloud seeding to increase rain or snow, decrease hail, reduce the destructiveness of hurricanes or dissipate fog. Inadvertent weather modification typically has referred to the impact of large urban cities on the local weather as evidenced by higher temperatures, altered wind circulations, increased aerosols and particles and enhanced precipitation and lightning strikes compared to surrounding rural areas. This chapter primarily will address cloud seeding, then inadvertent weather modification, and follow with a discussion of lessons these endeavors may provide in considering future climate modification. 

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