Resistance frost

Vineyard site is important to wine quaUty and character and interacts with variety. The general climate must not be too cold, too hot, or too humid. A mild, dry climate that still induces a dormant season, like the Mediterranean area and California, is desirable. A relatively constant weather pattern year-to-year is also sought. The nearer to the limits of cold tolerance, for example, that the climate comes, the more likely are disastrous vintages. The modifying influence of close bodies of water, sun-facing slopes, or frost-resisting air drainage can make one vineyard more desirable than another nearby. 

Concrete, Mortar, and Plaster. Citric acid and citrate salts are used as admixtures in concrete, mortar, and plaster formulations to retard setting times and reduce the amount of water requited to make a workable mixture (172—180). The citrate ion slows the hydration of Portland cement and acts as a dispersant, reducing the viscosity of the system (181). At levels below 0.1%, citrates accelerate the setting rate while at 0.2—0.4% the set rate is retarded. High early strength and improved frost resistance have been reported when adding citrate to concrete, mortar, and plaster. 

Adequate capacity and construction Designed to hold spillage Properly lit and ventilated Fire- and frost-resistant... 

When populations of Abies differing in frost resistance and altitude of origin are grown at the same sites they show marked differences in seed... 

Fig. 8. Frost resistance in populations of Abies sachalinensis within the boreal forest ecosystem, (a) Frost resistance and variance in resistance with altitude (b) seed characteristics of populations all grown in the lowlands (after Eiga Sakai, 1984).

Frost-Resistant Formulation for Hydraulic Fracturing Fluids [147]... 

A frost-resistant formulation from a Russian patent [147] is given in Table 17-19. The composition has a frost resistance down to —35° to —45° C. 

Storage requirements Suitable siting Adequate capacity and construction Designed to hold spillage Properly lit and ventilated Fire- and frost-resistant Designed so that containers can be safely stacked and moved Clearly marked Kept locked except when in use... 

In the Andes, nearly all of the about 160 varieties of wild potatoes, and two of the eight cultivated species are toxic. Some frost-resistant species that grow above 3600 m have high levels of alkaloids, which are bitter and potentially toxic. These are hybrids between Solanum stenotonum and wild potatoes such as Solanum megistacrolohum and Solanum acaulc. Other secondary plant compounds in potatoes are saponins, phytohemagglutinin, proteinase inhibitors, sesquiterpene phytoalexins, and phenols. 

Powers, T.C. (1945) A working hypothesis for further studies of frost resistance of concrete. 

The reduction in porosity, decreased water content, and air entrainment that results when latexes are used in mortar and concrete mixes make them much more resistant to freezing and thawing conditions than conventional mortar and concrete. Figure 6.17 presents the freeze-thaw durability in water (-18 to 4°C) of combined water-and dry-cured SBR-, PAE- and EVA-modified mortars [98], The frost resistance of mortars made with these latexes is markedly improved even at polymer-cement ratios of 5%. However, an increase in the polymer-cement ratio does not necessarily produce further improvement in freeze-thaw resistance. EMM and EMC, when exposed to outdoor conditions involving freeze-thaw, UV radiation and carbonation show better weatherability when compared with conventional mortar and concrete. 

Fujiwara, H., Tomita, R. and Shimoyama, Y. (1994). A Study of the Frost Resistence of Concrete Using an Organic Shrinkage Reducing Agent, ACI SP-145-34, 643-55. 

The use of superplasticizers in air-entrained concrete has caused much debate. Two main problems are associated with superplasticized air-entrained concrete (1) a decrease in air content by 1-3% when slump is increased from 75 mm to 220 mm after the addition of the superpiasticizer to create flowing concrete, and (2) a change in the air void system to less desirable values. However, most investigators [10-11, 12] have shown that, although the air-void spacing factor required for adequate frost resistance is altered, the change did not necessarily affect the freeze-thaw durability of... 

In spite of the decades of use of air-entraining agents (AEA) for the improvement of frost resistance of concrete, there has been a significant increase in reported cases of poor performance of concrete exposed to freezing and thawing, particularly where de-icing salts are used. Examination of specimens from a large number of concrete structures showed that only about half of the structures had an air-void system (AVS) that met the... 

Frost-resistant (hardy) plants are less sensitive than others to damage by low temperatures that is caused by water loss and intracellular, ice-crystal formation. Production of such highly hydrophilic proteins as glycoproteins would constitute a potential mechanism, through the formation of hydrogen... 

Raffinose occurs only at low concentrations in the leaves of plants, but accumulates in the storage organs during the process of development. It has been generally observed that the level of raffinose increases as the tissue loses water this 108-1i3,u6-m js a characteristic feature of maturation of seeds and the hardening process of winter-hardy plants. The hardiness of several plants towards desiccation and elevated temperature may be compared to the property of frost resistance.125-134 When the heat resistance reaches a maximum in the summer, the frost resistance is at its minimum. 

Stachyose and its homologs primarily occur in seeds and storage organs. Later research showed the presence of these oligosaccharides in the leaves of several plants,184 where they accumulate, especially during the winter, at a concentration parallel to that of sucrose. At this concentration, they provide frost resistance to the plant (see Section II,2,f) rather than serving as storage carbohydrates. 

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