Interface pressures

As a practical point, it should be noted that the separation force will change with time. This is because the modulus, E, will decrease with time. Suppose that in this Example, the assembly is to be maintained in position for 1 year and that during this time the modulus decreases to half its initial value (the 1 year modulus would be obtained from the creep curves in the normal way). The above analysis shows that the interface pressure would then be half its initial value (because Sr is fixed) and this in turn means that the separation force would become 5(K) N instead of 1 kN. 

For a specific resin, the shear stress at the interface depends on the temperature of the interface, pressure, and the sliding velocity, it also depends on resin type, additives and additive levels, and the rheological properties of the resin. Stresses at the interface and the coefficients of friction for numerous resins have been published previously from two sources, and the data can be found in the references [15-31]. Additional stress data are provided in Appendix A4 and in several of the case studies in Chapter 12. 

Chua, P.S. and Piggott, M.R. (1992). Mechanical properties of the glass fiber-polyester interphase. Part 3 - Effect of water on interface pressure and friction. J. Mater. Sci. 27, 925-929. 

Therein, A denotes the interface pressure (whole pore pressure), p l the realistic pressure, T denotes the partial effective Cauchy stress tensor and I is the unit tensor. With the expression A = ns A + nL pLR + nG pGR (Dalton s law), the constrain... 

Figure 13 (a) Pressure balance at the liquid-liquid interface. Pressure difference is balanced with Laplace pressure when the two phases are separated, (b) When the pressure difference between the two phases is larger than the maximum Laplace pressure, the organic phase moves toward the aqueous phase, (c) When the pressure difference is lower than the minimum Laplace pressure, the aqueous phase moves toward the organic phase. Abbreviation Aq., aqueous phase, Org., organic phase (Aota et al., 2009a). 

That is, moisture Is flov/ing toward the interface at a rate of 94,4 xg/s but flowing from the interface to the outdoors at a rate of only 3.9 ng(s. Noting that the interface pressure cannot exceed 234 Pa, these results indicate that moisture is freezing in the insulation at a rate of... 

An early understanding of material removal rate (MRR) from two surfaces in contact was developed by the glass polishing industry, where MRR became represented in what is known as Preston s equation MRR = kPv. In this empirical equation, the MRR is seen as a linear function of the pressure between the working and the worked surfaces (P) and the shear velocity between the two surfaces (v). This equation has stood the test of time and still forms the basis of approaches to and control of the CMP process. However, it can readily be shown that neither P nor v can be primary variables in the removal of material from a surface. Material is only accelerated (removed) in the direction of an applied force. The interface pressure P represents a force per unit area but is applied compressionally and normal... 

More specifically, in terms of interface pressure p = P/A, A 2jtrL being the peripheral area of the cylindrical surface of longitudinal length L,... 

ANL has constructed a tribology test rig that operates at the speed and interface pressure of the TIVM compressor/expander vanes at full power. This test rig is depicted in Figure 2. Initial dry friction and wear tests with stainless steel and low friction engineered polymer samples provided by Mechanology have indicated an acceptable friction coefficient at the TIVM operating conditions and wear rate consistent with the lifetime requirement. Additional tests are being conducted with high humidity and different material combinations. 

FIGURE 44.6 Finite-element analysis employed to determine the sensitivity of interface pressure to socket-shaped rectification (a) limb and socket (b) elements in layers representing idealized geometry of bone, soft tissue, and socket liner (c) rectification map of radial differences between the external free shape of the limb and the internal dimensions of socket and (d) FE predictions of direct pressure. (Courtesy of Zhang Ming, King s College, London.)... 

Here, Pq is the air pressure without disturbance Pi is the pressure of air shock wave fronts Px is the interface pressure of detonation products and air. 

Keywords Interface Pressure Crystallization Surface tension... 

Isotherms (interface pressure n [mN/m] area per molecule A [A ]) are usually measured by continuously compressing the film, which has been prepared on top of an electrolytic subphase. In this experiment, the interface pressure k A) = 7o - y A) [i.e. the difference of surface tensions without (y ) and with an interface film] is determined by monitoring the surface tension y A). For the phospholipid L-a-dimyristoyl phosphatidic acid (DMPA) a set of data at pH = 6 and various temperatures of the subphase was measured by Albrecht et al.9 and is reproduced in Fig.l. 

The interface pressure drop, APj is obtained from the Young-Laplace equation ... 

The pressure drop was found to be highly affected by the unit cell size. By changing the flow ratios, the sizes of the continuous and dispersed phases changed, thus varying the total number of interfaces in the system, and consequently the fiictional and interface pressure drop terms. 

Jafari A, Shirani E, Ashgriz N (2007) An improved three-dimensional model for interface pressure calculation in free-surface flows. Int J Comput Fluid Dyn 21(2) 87-97... 

MEASUIUNG INTERFACE PRESSURE IN COMPRESSION GARMENTS FOR BURNS PATIENTS... 

A Finnie, Interface pressure measurranents in leg ulcer management , British J of Nursing, 2000 23 Mar-Apr 12 9(6 Suppl) S8-10. 

Fig 4. Bar chart showing interface pressures measured on three different sites using a single chamber leg garment... 

A Satpathy, S Hayes, S R Dodds, Is compression bandaging accurate The routine use of interface pressure measurement in compression bandaging of venous leg ulcers , Phlebology, 2006 2136-40. 

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