EM mechanism

The two-cycle engine gives ideally twice this power. For double-acting engines,multiply these figures by 2. If Em = mechanical efficiency, the brake horse-power is Hu = EmHx. Values of Em are given by Lucke as follows-... 

The duty of a pump is its performance based on the output in foot-pounds per 1,000 lb. of dry steam, or per 100 cu. ft. of air, or per 1,000,000 B.t.u. furnished by the boilers at appropriate pressure. The duty of a steam pump can bo calculated approximately from the indicator diagram (either actual or ideal) by the formula card duty = 144,000 pv, and duty = card duty/E mEs where p = mean effective pressure of whole steam end referred to the area of any one cylinder, v = specific volume of steam at the terminal pressure in this same cylinder, Em — mechanical efficiency, and E = Steam efficiency, comprising all steam losses. 

This chapter is organized as follows. Eirst, the EM mechanism of SEIRA is briefly described for a better understanding of the technique, and this is followed by experimental aspects of the studies. Then several electrochemical systems studied by ATR-SEIRAS are described. Since SEIRA studies before 1997 have already been summarized in some review articles [8-10], this chapter deals mainly with the work performed after 1998. 

Fig. 8.3 Schematic representation of the EM mechanism of SEIRA on an island metal film. Incident photon field polarizes the metal particles and the dipole p generates an enhanced local electric field around the Islands and excites adsorbed molecules. The...

Eisenschenk FC, Houle JJ, Hoffinann EM. Mechanism of scrum resistance among Brucella abortus isolates. Vet Microbiol 1999 68 235-244. 

On the basis of the EM mechanism one can approximately predict the relative enhancements of the different vibrational modes for surface species. Since the component of the enhanced local electric field perpendicular to the surface has the largest enhancement, the vibrational modes with the totally symmetric polarizability tensor component (a ) have the strongest enhancement. The vibrational modes with the nontotally symmetric polarizability tensor elements (Uxz or Uyz) are less enhanced. Vibrational modes with the polarizability tensor... 

Merchant EM. Mechanics of the metal cutting process 1. Orthogonal cntting and a type 2 chip. J Appl Phys 1945 16(5) 267-75. 

The SERS selection rules can be used to infer molecular orientation. For a situation where only the EM mechanism is important, a set of SERS selection rules can be derived. The expression for the effective polarizability when an enhanced local electric field of a rough surface bathes the adsorbed molecule is given by equation 1, below (4) ... 

For a recent review on the EM mechanism of enhancement see Schatz and Van Duyne. ° The theoretical approach allows the calculation of enhancement factors for metal particles of different sizes and shapes. It is, in fact, electromagnetic enhancements that define surface-enhanced spectroscopies. 

Interaction of an EM field with a nanostructured metal surface also strongly influences other optical phenomena, namely absorption and luminescence. Surface-enhanced infrared absorption (SEIRA) of monolayers of benzoic acids on thin Ag island films was first observed in 1980s (Hartstein et al. 1980). The EM mechanisms is attributed to a local field enhancement and, correspondingly, to an enhancement of the absorption cross-section. Absorption can be enhanced generally by a factor of 10 -10 (Osawa 2001 Aroca 2006) and SEIRA is used as a complementary technique to SERS in some cases (Aroca 2006). 

Fluorescence (which is a special case of luminescence) in the vicinity of plas-monic metal can be both surface-enhanced and surface-quenched (Weitz et al. 1983). The fluorescence is a stepwise process involving first absorption which is enhanced by EM mechanism. For the second step (emission), the presence of metal... 

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