Memory effect, lack

There does exist a different approach to the derivation of Master Equations using the elimination of the environmental degrees of freedom. This leads to equations which lack the memory effect. This has been formally presented in Refs. [Grabert 1977 Grabert 1978], Occasionally the same philosophy has been applied to various problems [Alhassid 1980 Buzek 1998], The method is presented in Sec. 9.2 of Ref. [Breuer 2002], Here we formulate the principle in terms of the technique presented above. 

Since the advent of hyphenated MS techniques, gas chromatography (GC)-MS in the 1980s and LC-MS in the 1990s autosamplers have become a necessity at the front of MS-based instrument systems. Indeed the autosampler is a critical component of any modem LC-MS-based analysis system. Autosamplers have evolved to meet the increased demand requirements of automated well-based MS analysis. The primary figures of merit for autosampling devices are robustness, speed, lack of memory effect, swept volume, plate capacity, integration with MS software, and flexibility ... 

Lack of memory effect (carryover) A mle-of-thumb for carryover is that... 

Chemical transformations also permit one to enhance substantially the sensitivity of determination, for example, as a result of the transformation of a non-detectable compound into a detectable one. As an example. Fig. 12 [32] illustrates a chromatogram of benzyl esters of organic acids. The conversion of organic acids into non-polar esters not only dramatically improves the quantitative characteristics of analysis (lack of memory effects, symmetrical peaks, etc.) but also substantially lowers the detection limit. For example, formic acid is not detectable by a flame-ionization detector, whereas... 

The phenomenon of shape memory effect in SMPs is brought about by large changes in elastic modulus, E, above and below the transition temperature. Figure 1.3 shows a typical modulus behaviour of SMPs with temperature. At a temperature above the transition, the polymer enters a rubbery elastic state, and hence the elastic modulus of the polymer is much reduced. Consequently the polymer can be easily deformed by application of an external force (Bar-Cohen, 1999 Liu et ah, 2007). If the material is allowed to cool below its transition temperature, under reasonable strain, its temporary deformation becomes hxed. At this stage, the polymer lacks its rubbery elasticity and displays a high modulus. This state is called the glassy state. This deformation can be recovered when the polymer is heated above the transition (Hu, 2007). 

There are also a few limitations of GC-MS. The problems encountered previously by several investigators have been the poor precision and accuracy of isotope ratio data, the memory effect during the sequential analysis of samples with different isotope ratios, and the lack of suitable chelating agents. In addition, the contributions of the different isotopes of C, N, S, etc., present in the chelating agent need to be accounted for, particularly when studying the enrichments in different samples followed by tracer administration (intravenous or oral). 

More recently, a closer inspection of the transient stress rheology for thickening systems has revealed more complicated patterns, such as structural memory effects. Berret et al. [78] and Oeschlager et al. [93,107] have observed that the transient mechanical response also depended on the thermal and shear histories. Samples having been treated thermally, e.g., heated up to 90 °C for 2h, behaved very differently from samples freshly prepared or already sheared. The induction time couid last several hours, and was not proportional to the inverse shear rate, as mentioned previously. It was concluded that the lack of reproducibility under certain thermal and shear conditions might indicate that these surfactant solutions were characterized by long-lived metastable states. 

The field of nanotribology evolves around the attempts to understand the relationship between macroscopic frictional forces and the microscopic properties of the embedded system. Recent revival of interest in friction [/, 2, 3, 4, 5, 6, 7, 8] has unraveled a broad range of phenomena and new behaviors which help shed light on some fundamental concepts which are already considered textbook material. These include the static and kinetic friction forces, transition to sliding, thinning, and memory effects, which have been widely discussed but whose microscopic origins are still lacking. 

Unlike shape memory alloys, shape memory polymers lack mechanical stiftoess and recovery stress[6]. However, very limited work can be found on improvement of recovery force of shape memory polymers[4, 7-11]. It was shown that the addition of reinforcing fillers enhanced the strength and stifihess of polymer matrix. But the reinforcement itself also imparted negative effect on shape recoverability. The filler content used in these work was... 

An epidemiological study found significant increases in neurasthenia (i.e., fatigue, depressed mood, lack of initiative, dizziness, and sleep disturbances) in workers who were chronically exposed to jet fuels by inhalation, oral, and/or dermal exposure (Knave et al. 1978). Also, attention and sensorimotor speed were impaired, but no effects were found on memory function or manual dexterity. EEG results suggest that the exposed workers may have had instability in the thalamocortical system. The limitations of the study are discussed in detail in Section 2.2.1.2 under Respiratory Effects. 

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