EMC effect

Common cause Diversity means that the safety function is to be carried out in a redundant manner with different hardware/design principles/even completely different technologies (e.g., one a mechanical system, the other an electronic system so that in the former system the EMC effect will not exist). In practice a real common cause is dif cult to find because the failures of a multichannel system must by definition of a common cause occur at exactly the same time. The same hardware will always have different strengths and thus fail at a slightly different time. A well-designed safety system can take advantage of this gap in time and detect one failure before the other failure occurs. 

Finally we note that the internal Fermi motion in a nucleus can be treated by the above approach. This will be discussed in relation to the so-called EMC effect in Section 17.1.3. 

Concisely, what has come to be known as the EMC effect is simply the statement that nucleons bound in nuclear matter behave differently from free nucleons in deep inelastic scattering. More precisely, the nucleon scaling functions appear to have a different x dependence when measured for free nucleons or for nucleons bound in nuclei. The deviation of the nuclear scaling functions from the free nucleon case increases with the atomic number A while remaining qualitatively similar for all nuclei. A broad variety of theoretical explanations have been offered ranging from QCD mechanisms to conventional nuclear physics phenomena. Now, the dust is slowly setting, and it appears possible to take stock of the situation. 

Sodium Hydroxide. Before World War 1, nearly all sodium hydroxide [1310-93-2], NaOH, was produced by the reaction of soda ash and lime. The subsequent rapid development of electrolytic production processes, resulting from growing demand for chlorine, effectively shut down the old lime—soda plants except in Eastern Europe, the USSR, India, and China. Recent changes in chlorine consumption have reduced demand, putting pressure on the price and availabiHty of caustic soda (NaOH). Because this trend is expected to continue, there is renewed interest in the lime—soda production process. EMC operates a 50,000 t/yr caustic soda plant that uses this technology at Green River it came onstream in mid-1990. Other U.S. soda ash producers have aimounced plans to constmct similar plants (1,5). 

Also, chronic-duration studies have not generally shown adverse effects on organs of the immune system. Routine gross and histopathologic examination of the lymph nodes and thymus of rats, mice, and dogs exposed to endosulfan for 2 years at doses of up to 2.9 mg/kg/day (Hoechst 1989a), 2.51 mg/kg/day (Hoechst 1988b), and 1 mg/kg/day (EMC 1967), respectively, revealed no adverse effects. However, these studies did not assess immune function directly. 

Fig. 8.5 Demonstration of IFNa2b functionality by the ability of IF-Na2b to protect HeLa cells against the cytopathic effect of encephalomyocarditis virus (EMC). Chloroplast derived IFNa2bwas as active as commercially produced Intron A.

A similar roasting effect was shown for the water adsorption isotherms of hull flours except that the most severe roasting did not affect the EMC as dramatically as it did whole flours for the highest aw. The water asorption isotherms of high protein flours indicate that roasting did not affect EMC of these flours... 

Martins and Banks (1991) modified pine and wood samples with phenyl or butyl isocyanate and investigated the water vapour sorption properties of the modified wood. Modification resulted in a reduction in EMC at a given RH up to about 35 % WPG with butyl isocyanate, although reaction with phenyl isocyanate above 25 % WPG resulted in an increase in sorption due to cell wall damage caused by the reaction. The butyl derivative was more effective at reducing hygroscopicity over all the WPGs studied. 

Ibach and Rowell (2000) reacted wood with propylene oxide and butylene oxide, and determined the decay resistance of the modified wood. Propylene oxide modification was found to be ineffective in preventing decay by G. trabeum, whereas butylene oxide modification proved to be effective at 23 % WPG. Reaction of epicholorohydrin with wood was found to provide decay protection at 31 % WPG against G. trabeum, although such modification did not lower the EMC significantly (Ibach and Lee, 2002). It was concluded that decay protection was due to substrate modification. 

Militz (1993) treated European beech with DMDHEU and evaluated the effectiveness of a variety of commercial catalysts. It was found that temperatures of 100 °C were necessary for effective curing of the resin. The ASE was calculated from the dimensions at 100 % RH in comparison to the sample dimensions at 30 % RH, rather than in a water-soak test, so that any possible effect of leaching was not determined. The highest ASE measured in this way was 75 %. The EMC of the treated samples was also determined and found to be higher than unmodified samples in all cases. 

When the poor anodic stability of DMC or EMC alone on a similar cathode surface is considered, the role of EC in stabilizing the solvent system becomes obvious. A conclusion that could be extracted from these studies is that the existence of EC not only renders the electrolyte system with superior cathodic stability by forming an effective SEI on the carbonaceous anode but also acts as a key component in forming a surface layer on the cathode surface that is of high breakdown potential. It is for its unique abilities at both electrodes that EC has become an indispensable cosolvent for the electrolyte used in lithium ion cells. 

In a further effort to identify the active intermediate that initiates the reaction, they tested the effect of a few possible ingredients on the production of EMC based on the knowledge about the chemical composition of the SEI on carbonaceous anodes. These model compounds included Li2C03, LiOCHs, and LiOH, while lithium alkyl carbonate was not tested due to its instability and therefore rare avail-ability. The results unequivocally showed that LiOCHs effectively catalyzes the ester exchange. 

Figure 77. Effect of TFP concentration in different baseline electrolytes on the rate performance of the lithium ion cells (a) 1.0 m LiPFe/EC/EMC (1 1) (b) 1.0 m LiPFe/ PC/EC/EMC (3 3 4). (Reproduced with permission from ref 530 (Figure 5). Copyright 2003 The Electrochemical Society.)...

Description The ExxonMobil Chemical (EMC) process offers commercially proven technologies for efficient recovery and purification of high-purity n-paraffin from kerosine feedstock. Kerosine feedstocks are introduced to the recovery section where the n-paraffins are efficiently recovered from the kerosine stream in a vapor-phase fixed-bed molecular sieve adsorption process. In the process, the n-paraffins are selectively adsorbed on a molecular sieve and subsequently desorbed with a highly effective desorbent. 

Effect of Relative Humidity and Sorption History. An indirect method for estimating wood moisture content is to measure its equilibrium relative vapor pressure h. This is related to wood moisture content by a sorption isotherm. The percent relative humidity (H) or relative vapor pressure (h) (H = 100 h) is the most important factor in determining the EMC for wood. A curve showing EMC as a function of percent relative humidity or relative vapor pressure at constant temperature is called a moisture sorption isotherm. 

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