Fluctuation enhancement

As can be seen from Fig. 6, liquid-liquid demixing clearly precedes crystallization in case Cl. Moreover, crystallization in this case occurs at a higher temperature than in cases C2 and C3. Apparently, the crystallization takes place in the dense disordered phase (which has a higher melting temperature than the more dilute solution Fig. 5). In case C2, the crystallization temperature is close to the expected critical point of liquid-liquid demixing, but higher than in case C3. This suggests that even pre-critical density fluctuations enhance the rate of crystal nucleation. 

Thus, V undergoes fluctuation-enhancement as the instability point K — 0 is approached. In practice, however, such fluctuations are extremely small and undetectable for realistic values of K (say, 103 104 Pa) unless gels are very small (say, 100 A in length). On the other hand, the specific heat Cn at constant II is larger than the specific heat Cv at constant V by... 

This was called the fluctuation enhancement theorem by M. Suzuki, Prog. Theor. Phys. 56, 77 (1976). 

J. van Egmond and G. G. Fuller, Concentration fluctuation enhancement in polymer solutions by extensional flow, Macromolecules, 26,7182 (1993). 

Podgornik R, Rau DC, Parsegian VA. The action of interhelical forces on the organization of DNA double helices fluctuation-enhanced decay of electrostatic double-layer and hydration forces. Macromolecules 1989 22 1780-1786. 

Evans, E.A., Parsegian, V.A. Thermal-mechanical fluctuations enhance repulsion between bio-molecular layers. Proc. Natl. Acad. Sci. 1986, 83, 7132-6. 

FLUCTUATION-ENHANCED CHEMICAL/BIOLOGICAL SENSING AND PROMPT IDENTIFICATION OF BACTERIA BY SENSING OF PHAGE-TRIGGERED ION CASCADE (SEPTIC)... 

Keywords. Fluctuation-Enhanced, gas sensing, FES, noise, phage-triggered, ion cascade, SEPTIC. 

Recently, a new method, Fluctuation-Enhanced Sensing (FES) has been discovered and developed which mimics the biological way of smelling. 

Fluctuation-enhanced sensing has outstanding properties compared to traditional methods ... 

Figure 2. Fluctuation-enhanced sensing (molecular counting) simulation results by using the amplitude density function...

Though fluctuation-enhanced sensing has been proven to be superior to classical methods many important qnestions have to be solved before the method can be indnstriahzed, snch as signal separation of simultaneously present chemicals, selection of the most appropriate sensor materials and optimal sensor geometries, etc. 

Figure 3. Fluctuation-Enhanced Sensing using power density spectra.

Fluctuation-Enhanced methods can be used to detect biological agents. Existing methods are slow require culturing, laborious assaying by trained personnel and bulky equipment (except some special narrowly apphcable methods for quick tests which can identify only... 

We have introduced the basic principles of Fluctuation Enhanced Sensing and demonstrated its superior sensitivity and selectivity for gases and bacteria detection. It is clear from the presented results that Fluctuation Enhanced Sensing (FES) and the SPETTC method in particular, offer significant advantages when compared with traditional methods. 

L.B. Kish, Y. Li, J.L. Solis, W.H. Marlow, R. Vajtai, C.G. Granqvist, V. Lantto, J.M. Smulko, G. Schmera, "Detecting Harmful Gases Using Fluctuation-Enhanced Sensing", IEEE Sensors Journal 5 (2005) 671-676. 

J. Ederth, J.M. Smulko, L.B. Kish, P. Heszler and C.G. Granqvist, "Comparison of classical and fluctuation-enhanced gas sensing with PdxW03 nanoparticle films". Sensors and Actuators B 113 (2006) 310-315. 

J.L. Solis, G. Seeton, Y. Li, L.B. Kish, "Fluctuation-Enhanced Sensing with Commercial Gas Sensors", Sensors Transducers Magazine 38 (2003) 59-66. 

G. Schmera, L.B. Kish, "Fluctuation Enhanced Chemical Sensing by Surface Acoustic Wave Devices", Fluct. Noise Lett, 2 (2002) LI 17-L123. 

The situation in TTF-TCNQ is potentially much richer than that in KCP. Transverse correlations in this material are probably considerably, stronger in one than in the other of the two transverse directions. This can lead to a complicated 3—2 — 1 dimensional cross-over for n — 2. Empirically2 , however, the fluctuation tails do not seem to be as large in this material as they are in KCP. It might well be that the structural transition in TTF-TCNQ falls into the symmetric limit, with only the fluctuations enhanced. It would be interesting therefore to have more data about the temperature behaviour of all three, or at least of two correlation lengths. 

As more and more (swollen) micelles are produced because of an increase of amphiphile amount, a point is reached where they start interacting according to the so-called percolation or clustering phenomenon, mostly studied for inverse micellar systems by conductivity [12-16]. This typically occurs when the micellar volume attains 20% of the overall volume but could take place even at a lower proportion if a charge fluctuation enhances the attraction of neighboring droplets [17], which could be promoted by other forces related to electric field or solute structure [18]. 

Region I Tc s decreases with increasing temperature and decreasing strain rate. Thermal fluctuations enhance dislocation motion. 

Fig. 5.9 Illustration of macroscopic enhancement of fluctuation from the initially microscopic one. Fluctuations in the initial and final regime can be well described by Gaussian approximation. In the transient regime fluctuation enhances macroscopi-cally, as can be calculated based on a generalised scale transformation of time, (a) Initial regime, (b) Scaling regime, (c) Final regime.

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