Minimal thickness

Taking all these conditions into account the estimation for the minimal thickness difference of steel which could be perceptible at granularity levels equal to the limiting values for granularity in EN 584-1 results in the values given in Table 1. 

Film manufacture also requires special considerations in the case of polypropylene in order to ensure small crystal structures and hence high clarity. Chill-roll casting processes may be used and these give films of high clarity and minimal thickness variations at high rates of production. Blown film processes can, however, give superior mechanical properties and in addition equipment costs are lower, and in consequence the process is more economic for lower tonnage production. 

For high-yield efficiency, a thin dielectric with a high-dielectric constant should be used. Glass is the most practical material. High-dielectric strength is required to minimize puncture, while minimal thickness maximizes yield and facilitates heat removal. 

The idea of 9 having a maximum value of unity is simplistic. Try this quick experiment take the pan used to prepare a curry and try to wash it clean. There will be a stain adjacent to the metal, above which is a layer of curry sauce. The stain is thin - possibly even transparent - which we call the adsorbed layer. The layer of stain has a minimal thickness and it is difficult to remove. Conversely, we call the overlayers of curry sauce bulk material , which can take any thickness and are relatively easy to remove, even with a fingernail. 

Fig. 10.1 (a) Geometrical model of human erythrocyte. and are maximal and minimal thickness of erythrocyte, respectively. R is erythrocyte radius, (b) Schematic drawing of erythrocyte gross-section and light ray part reflected on interface air-cell, cell-air and air-substrate... 

Sample Preparation. Solid samples were finely powdered and dusted onto mylar tape. In order to minimize thickness effects some model compound samples were diluted with boron nitride. Liquid samples... 

It should also be emphasised that an initial period of interaction of elementary substances when there is still no compound layer and consequently there is only one common interface at which substances A and B react directly, is outside the scope of the proposed macroscopic consideration. The stage of nucleation of a chemical compound between initial phases is to be the subject of examination within the framework of a microscopic theory which would have to provide, amongst other parameters of the process, a minimal thickness sufficient to specify the interaction product formed at the A-B interface as a layer of the chemical compound ApBq possessing its typical physical and chemical properties. However, it can already now be said with confidence that this value is small in comparison with really measured thicknesses of compound layers and therefore can hardly have any noticeable effect on the shape of the layer thickness-time kinetic dependences observed in practice. 

Minimal thickness of the ArBs layer necessary for the ApBq layer to occur... 

Fig. 2.5. Schematic illustration of the concept of a minimal thickness of the ArBs layer necessary for the ApBq layer to occur and grow in the A-B reaction couple.

During the natural course of the process of formation of the ApBq and ArBs layers between elementary substances A and B when an A B specimen is given to itself at constant temperature and pressure, a correct ratio of their thicknesses is established automatically. However, if an A-ApBq-ArBs B specimen was prepared artificially, this ratio can hardly be expected to be correct. Therefore, during subsequent isothermal annealing of the specimen, one of the layers will shrink and can even disappear as occurred before its turn if, of course, by that time the other layer has not reached a minimal thickness required for the former to occur. Such a phenomenon was observed, for example, by G. Ottaviani and M. Costato74 with the PtSi layer in Pt-Pt2Si-PtSi-Si specimens and by K.N. Tu et alm with the CoSi layer in Co-Co2Si-CoSi-Si specimens. 

In most reaction couples, the layer formed first should reach a certain minimal thickness before the second layer can occur. Both compound layers will then grow simultaneously until the full consumption of one of initial substances A or B. 

Fig. 3.4. Schematic illustration of the transition from the linear to nonlinear stage of formation of the ApBq (lines T and 1), ArBs (line 2) and AiBn (line 3) layers between elementary substances A and B. The ApBq layer present initially first disappears and then occurs and grows again after the ArBs layer has reached the necessary minimal thickness Vmin.

Therefore, the derivative dx/dt becomes positive. This means that the ApBq layer will start to grow between the A and ArBs phases if, of course, the substance A is not consumed completely by that moment of time. The value, jVn, is again a minimal thickness of the ArBs layer to be attained before the ApBq layer can begin to grow (see Section 2.4 of Chapter 2). 

In the preparation of multi-layered ceramic membranes, the quality of the support is of crucial importance to the integrity of the membrane layers that are applied in the subsequent preparation steps. First, the surface roughness and homogeneity of the support will determine the integrity of these membrane layers, and, second the surface roughness determines the minimal thickness of the membrane layer for complete surface coverage. 

A comparison of the results is shown in Table I. It is clear that a reduced crosslink density is desirable for improved sensitivity. This must be optimized to ensure acceptable contrast and minimal thickness loss in unexposed regions. Although all the methods explored in this work gave improved sensitivity and acceptable contrast, it appears that the simplest and most reproducible method for achieving lower crosslink density is to modify the... 

Figure 18 (a) Overlay of the crystal structure of WTMb (thin) and the a structural model of CueMh based on computer modeling and energy minimization (thick) (b) Overlay of the crystal stmctnre of heme-cooper center in CcO (thin) and the same stmctnral model of CueMh (thick) as in (a). (Reprinted with permission from Ref 207. 2000 the American Chemical Society)... 

In slab calculations, a finite number of layers mimicks the semi-infinite system, with a two-dimensional (2D) translational periodicity. A minimal thickness dmin is required, so that the layers in the slab centre display bulk characteristics. Practically speaking, dm-,n should be at least equal to twice the damping length of surface relaxation effects, which depend upon the surface orientation. In plane wave codes, the slab is periodically repeated... 

Optimum thickness. At fixed composition a phase diagram of the catalyst layer can be generated, which establishes a relation between the optimum thickness interval of the catalyst layer and the target current density jo (or jo interval) of fuel cell operation. The optimum compromise between kinetic losses and mass transport losses is realized in the intermediate regime. The existence of an upper limit on the thickness beyond which the performance would start to deteriorate is due to the concerted impact of oxygen and proton transport limitations, whereas considered separately each of the effects would only serve to define a minimal thickness. 

An increase in the sensor sensitivity can be realized when decreasing dq. A minimal thickness around 55 p.m to limit mechanical fragility results in a fundamental frequency of 30 MHz [24]. The application of photolitho-... 

Dense homogeneous polymer membranes are usually prepared (i) from solution by solvent evaporation only or (ii) by extrusion of the melted polymer. However, dense homogeneous membranes only have a practical meaning when made of highly permeable polymers such as silicone. Usually the permeant flow across the membrane is quite low, since a minimal thickness is required to give the membrane mechanical stability. Most of the presently available membranes are porous or consist of a dense top layer on a porous structure. The preparation of membrane structures with controlled pore size involves several techniques with relatively simple principles, but which are quite tricky. 

Here one can Imagine a system with a membrane of minimal thickness, which would prevent the two solutions from being rapidly mixed via convection. 

The electrolyte membrane is an oxide ion conductive ceramic, whose thickness depends on the cell design. One may distinguish electrolyte-supported cell from electrode-supported cell (Fig. 15.6). In the first case, anode and cathode are deposited onto both faces of the electrolyte membrane. As a direct consequence, the membrane must be mechanically strong, and a minimal thickness of 100 pm is required. In the case of the electrode-supported cell, the anode is actually the mechanical support of the electrolyte first, and next the cathode on the top. Thus, the electrolyte thickness can be greatly reduced, down to 8 pm for classical SOFC devices. More recently, with the development of micro-SOFC, it can reach 100 nm to 1 pm. 

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