Hardy effect

Hardy effect.248-249 The internal return part of the ionization equilibrium is particularly hard to detect since it is almost completely independent of the concentration of anything in the bulk of the solution outside of the solvent cage. The extent of internal return will depend on the reactivity of the cage walls and their resistance to the escape of either ion. Unless internal return has been eliminated by the use of an extremely reactive cage wall, the measured rate is not that of the ionization but the lesser rate of ion pair dissociation. In the case of the acetolysis of a, a-dimethylallyl chloride (XXXIX), internal return is detectable by virtue of the fact that the chloride ion can return to either of two allylic carbon atoms.248... 

K.S. Weil, C.A. Coyle, J.T. Darsell, G.G. Xia, J.S Hardy, Effects of thermal cycling and thermal aging on the hermeticity and strength of silver-copper oxide air-brazed seals. J. Power Sources 152, 97-104 (2005)... 

The human impact on the environment affects many areas of our lives and future. One example is the effect of acid rain on biodiversity, the diversity of living things. In the prairies that extend across the heartlands of North America and Asia, native plants have evolved that can survive even nitrogen-poor soil and drought. By studying prairie plants, scientists hope to breed food plants that will be hardy sources of food in times of drought. However, acid rain is making some of these plants extinct. 

For organisms, the acidification of lakes may cause stealthy and almost imperceptible effects. At first, only very small changes can be detected, but as the waters become increasingly acidic, more and more species are eliminated. A pH of greater than 6 in a lake is required to ensure that most of the aquatic organisms will thrive. As a pH of less than 5 is reached, only a small number of very hardy plant and animal species survive. Figure 1 illustrates this progressive decline. 

Hardy, A.R. (1990). Estimating exposure The identification of species at risk and routes of exposure. In L. Somerville and C.H. Walker (Eds.) Pesticide Effects on Terrestrial Wildlife, 81-98, London Taylor Francis. 

When foreign electrolytes which do not react with the soap are present, the ions responsible for bringing about coagulation are the ones with charges opposite in sign to those on the dispersed particle. The effect of the valence of the ion follows the Schulze-Hardy rule for the precipitation of sols by electrolytes wherein the coagulating power of an ion increases considerably with the increasing valence of the ion. 

Seeram NP, Adams LS, Hardy ML and Heber D. 2004. Total cranberry extract versus its phytochemical constituents antiproliferative and synergistic effects against human tumor cell lines. J Agric Food Chem 52(9) 2512-2517. 

Thorarinsson, R., M.L. Landholt, D.G. Elliott, R.J. Pascho, and R.W. Hardy. 1994. Effect of dietary Vitamin E and selenium on growth, survival and the prevalence of Renibacterium salmoninarium in chinook salmon (Oncorhynchus tshawytscha). Aquaculture 121 343-358. 

The 1,700 ppm AEGL-2 is supported by studies in which no effects other than prenarcotic signs and/or narcosis were observed in rats and mice exposed at approximately 30,000 ppm for 4 or 6 h (Vlachos 1988 Hardy et al. 1989b Brock et al. 1995). Adjustment of the 30,000 ppm concentration by inter... 

A great many human fatalities associated with acute HCN exposure have occurred, but exposure concentrations are for the most part unknown. Acute exposures that failed to result in mortality were either to high concentrations for very short exposure durations (approximately 500 or 450 ppm for approximately 1.5 min or 6 min, respectively [Barcroft 1931 Bonsall 1984]) or to exposure concentrations and times that were estimated (>25 ppm for about 1 h [Parmenter 1926]). Monitoring studies indicate that workers were routinely exposed at <10 ppm (Hardy et al. 1950 Grabois 1954 Maehly and Swensson 1970). Occupational HCN exposures at 1-10 ppm were acceptable at the time of these surveys as 10 ppm was the maximum acceptable concentration for workers. More effective exhaust ventilation was implemented where re... 

Medical questionnaires were not given in the Grabois (1954) study. However, both NIOSH (1976) and ACGIH (1996) reviewed the study. NIOSH (1976) identified 5 ppm as a no-effect concentration using the data for the five plants presented by Grabois (1954). Similar exposures were reported in the studies of Hardy et al. (1950) and Maehly and Swensson (1970). 

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