General weather situation

FIGURE 4.14 The general Vb-weather situation displayed on the 500 hPa geopotential surface on August 19, 2005, 0000 UTC (ECMWF, with permission). Color figure on CD, Chapter 20.4. 

Following these general considerations of the source of protons and the role of oxidation-reduction reactions in chemical weathering, general weathering reactions can be written for silicate and carbonate minerals. Four situations are discussed ... 

Distribution of U-Th-Ra in weathering profiles. The first U-Th studies (Pliler and Adams 1962 Rosholt et al. 1966 Hansen and Stout 1968) generally showed a U loss relative to Th at the base of the profiles, and an enrichment in the uppermost horizons and/or in some accumulation layers. The development of weathering studies, however, point out that this situation is not to be generalized and that reverse trends can be observed even at the scale of a single toposequence (Fig. 11). 

Based upon these features another learning machine was constructed for the year 1982, describing the situation with exclusion of the months Septanber till December when the weather was in general too unstable. Fran that period 36 situations have been selected where conplaints were registered for at least two consecutive hours. These data were ccmpleted by another 36 situations without conplaints, selected exactly 24 hours before or after a period with complaints. 

The wood itself supplies the fourth requirement of the fungi, which is food. In order to prevent decay, it is necessary to deprive the fungus of one or more of these four requirements. It is out of the question in ordinary situations to deprive it of air and warmth and though moisture can sometimes be eliminated to a certain extent, this can nob be done when the wood is exposed to the weather. In general, therefore, the most effective method of preventing decays is to poison the food supply and upon this principle is based the use of most successful wood preservatives. ... 

The case of liquids is simpler than weathering in that it is es.sentially a two agent situation, liquid and temperature. However it is generally necessary to take account of the rate of diffusion of the liquid into the material, which may be slow in relation to the time scale of an accelerated test. Also, it is necessary to consider that there may be physical change (swelling) of the polymer as well as chemical degradation,... 

The mainstream adoption of TTS has been severely limited by its quality. Apart from users who have little choice (as in the case with blind people), people s reaction to old style TTS is not particularly positive. While people may be somewhat impressed and quite happy to listen to a few sentences, in general the novelty of this soon wears off. In recent years, the considerable advances in quality have changed the situation such that TTS systems are more common in a number of applications. Probably the main use of TTS today is in call-centre automation, where a user calls to pay an electricity bill or book some travel and conducts the entire transaction through an automatic dialogue system Beyond this, TTS systems have been used for reading news stories, weather reports, travel directions and a wide variety of other applications. 

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