Contact effect

Olefins, Diolefins, and Acetylenes. Members of this category having up to four carbon atoms are both asphyxiants and anesthetics, and potency for the latter effect increases with carbon chain length. Skin-contact effects are similar to those of paraffins. 

Ref 15. Contact effect against adult mites. Eoliar residue bioassay. Table 3. Principal Agricultural Applications of Abamectin Foliar Spray ... 

Contact of brass, bronze, copper or the more resistant stainless steels with the 13% Cr steels in sea-water can lead to accelerated corrosion of the latter. Galvanic contact effects on metals coupled to the austenitic types are only slight with brass, bronze and copper, but with cadmium, zinc, aluminium and magnesium alloys, insulation or protective measures are necessary to avoid serious attack on the non-ferrous material. Mild steel and the 13% chromium types are also liable to accelerated attack from contact with the chromium-nickel grades. The austenitic materials do not themselves suffer anodic attack in sea-water from contact with any of the usual materials of construction. 

If the release forms a vapor cloud that premixes with air before ignition occurs, and turbulence is developed (for example, by the flame front propagating through a process structure), the flame speed can accelerate sufficiently to cause a blast. This event is referred to as a vapor cloud explosion. In addition to blast effects, radiant heat and flame contact effects may also occur. Flashback to the source may cause a pool and/or jet fire. 

The main drawback in this type of thermometry is the presence of spurious thermoelectric powers due to chemical inhomogeneity, stress in conductors, contact effects in switches if present, etc. 

Hamadani, B. H. Natelson, D. 2005. Extracting contact effects in organic FETs. Proc. IEEE 93 1306-1311. 

In order to examine the contact effects on both yUi and jj,2, TOF was carried out on similar samples with different top and bottom contacts (gold, aluminum, copper, and Sn02). From the results, it can be concluded that both fix and 2 are independent of the top and bottom contact and also of the apphed field. These observations indicate... 

In this chapter, we use exclusively relativistically optimized or experimental geometries. Hence, we concentrate on direct relativistic effects only. They can be separated into scalar and spin-orbit/Fermi contact effects. In addition, there are, in both cases, core and valence contributions. 

Spin-Orbit/Fermi Contact Effects. While scalar relativistic effects seem to be sufficient for some systems like the metal carbonyls of Table I (even though it has been speculated (9) that spin-orbit might improve the agreement with experiment even further), there are other cases where this is not the case. We have chosen as an example the proton NMR absolute shielding in hydrogen halides HX, X = F, Cl, Br, I (7,9), Figure 1. This series has also been studied by other authors (34-38), and it may well be the most prominent example for spin-orbit effects on NMR shieldings and chemical shifts. 

Figure 1. JH absolute shielding in HX, X = F, Cl, Br, I. The figure illustrates the importance of spin-orbit/Fermi contact effects in these systems (9) scalar relativistic calculation (7) are unable to reproduce the experimental trend.

The three main barriers upon which pesticide will impinge are the skin, the lungs and the gastrointestinal tract. Each of these barriers possesses a unique structure and function which will influence the absorption of pesticide into the bloodstream. Although some product may exert local contact effects, it is usually only after they have been absorbed that, they exert their toxic effects therefore, it is important to understand the extent of the absorption. 

Although these two equations are mathematically identical, eq. (48) should be used when 5 is dominated by the pseudo-contact contribution and eq. (49) should be used when S 313 is dominated by contact effects, thus maximizing the slopes of the resulting straight lines (Reuben and Elgavish, 1980). Plots of Sf /(Sz)j vs Cj/(Sz)j (eq. (48)) or 5 vs... 

To segregate our possible contact effects, the same experiment was repeated with gold top-contact-structure pentacene TFTs also. A 0.5-pm film of parylene-C was deposited and the TFTs were measured without a patterning of the parylene. The TFT (W/L = 400/80 pm) characteristics before and after parylene passivation are compared in Fig. 15.10. Field-effect mobility has a 40% decrease from 2.3 cm2 V-1 s 1 to 1.4 cm2 V 1 s 1, while the threshold voltage stayed the same. 

Uses Pirimicarb is a colorless solid material. It is a selective systemic insecticide with contact effects on stomach (poison) and respiratory system (lungs). It is extensively used for the control of pests that infect a variety of crops (e.g., ornamentals, oilseeds, vegetables, cereals, greenhouse crops). Formulations include... 

Linuron, a substituted urea introduced by Hoechst in 1960, is employed primarily as a preemergence herbicide but it also has contact effect on foliage (Fig. 3). Linuron is used principally in soybeans, corn, sorghum, wheat, and potatoes. It is often mixed with other herbicides to broaden the weed spectrum. 

D.J. Gundlach, L. Zhou, J.A. Nichols, T.N. Jackson, P.V. Necliudovc, M.S. Shur, An experimental study of contact effects in organic thin film transistors, J. Appl. Phys. 100 (2006) 24509. 

Although the value of critical liquid mass velocity for kapp/kv 1 is above 0.3 g cm-2 s it is not a universal constant. It is a function of reactor geometry and catalyst-bed packing and, in some instances, no effect of mass velocity on the contacting effectiveness can be observed. 

There is little correlation between flow uniformity and the contacting effectiveness. The contacting effectiveness increases even when flow uniformity remains poor. 

The interstitial bed geometry, catalyst shape, and size play important roles in the contacting effectiveness. 

At high liquid mass velocities, good contacting effectiveness can be obtained even for reactor/catalyst diameter ratios as low as 1.4/1. 

Figure 6-10 Contacting effectiveness as a function of liquid loading (as proposed by Satterfield %...

For the highly contracted f electrons of Gd(III) type ions, the magnetic interaction is mediated by the spin polarized 5d, 6s valence electrons. To a good approximation, the 4f exchange field can be viewed as a type of contact effect [6], which only exert its influence on the orbitals centered on the Gd atom. Both the valence 5d and 6s electrons can penetrate to some extent... 

Lanthanide reagents produce shifts through complexation, dipolar and contact effects. Complexation shifts are small and are measured using diamagnetic La(III) or Lu(III) chelates. ... 

In addition to wrong-way shifts, there are other methods to assess whether contact shifts occur for a nucleus. One is to compute sets of internal ratios of the shifts of protons for different metals or for directly attached H or C nuclei. Anomalies in these ratios are indicative of a contact contribution. Chelates of gadolinium, which has an isotropic f configuration, can only produce shifts by complexation or contact effects . Theoretical parameters for the relative contributions of contact and dipolar shifts for different lanthanide metals can be used to construct plots that indicate whether or not the shifts of a particular nucleus are purely dipolar or have a contact contribution Theoretical parameters indicate that the proportion of contact contribution to the shifts occurs in the order Eu > Nd > Ho > Er > Tb > Dy > Tm > Using the theoretical values... 

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