Lowercase Greek Letters

80 Concrete strain on the tension fiber prior to FRP strengthening 

8ccu Design ultimate strain of confined concrete 

Sfdjid Reduced design strain of FRP reinforcement for confined members of r.c. or masonry 

8ft Characteristic rupture strain of FRP reinforcement efdd Maximum strain of FRP reinforcement before debonding emeu Ultimate compressive strain of confined masonry 8mu Ultimate compressive strain of masonry 8yd Design yield strain of steel reinforcement II Conversion factor 

Osd Stress normal to masonry face acting on the bonded surface area between FRP reinforcement and masonry Tb,e Equivalent shear stress at the adhesive-concrete interface pu Curvature at the ultimate limit state 

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The number of the moving electromagnetic waves that pass a fixed point in 1 sec is called the frequency of the light. Its symbol is the lowercase Greek letter nu, v. It is expressed in waves (most often called cycles) per second, or hertz (Hz). In mathematical formulas, the unit is reciprocal seconds (sec- ). 

Electronegativity. The ionization energy and electron affinity are characteristics of isolated atoms they say very little about how two atoms will interact with each other. It would be nice to have an independent measure of the attraction an atom has for electrons in a bond formed with another atom. Electronegativity is such a quantity. It is represented by the lowercase Greek letter chi, x Values can be calculated using one of several methods discussed below. Values of x always relative to one another for a given method of calculation, and values from one method should not be used with values from another method. 

Now that we know how to find the cell volume, we can use some previous information to calculate an important property of a material, namely, its density, which we represent with the lowercase Greek letter rho, p. For example, aluminum has an FCC space lattice. Recall that there are fonr atoms in the FCC unit cell. We know that each aluminum atom has an atomic weight of 27 g/mol. From Table 1.11, the cnbic lattice parameter for alnminnm is 4.05 A, or 0.405 nm (4.05 x 10 cm). This gives ns a volume of = 6.64 x 10 cm. You should confirm fhaf fhe fheorefical densify for aluminum is then ... 

The minns sign in Eq. (4.2) arises dne to the fact that in order for there to be heat flow in the +y direction, the temperatnre gradient in that direction must be negative—that is, lower temperature in the direction of heat flow. If the temperature gradient is expressed in units of K/m, and the heat flux is in J/m - s, then the thermal conductivity has units of J/K m s, or W/m K. A related quantity is the thermal diffusivity, which is often represented by the lowercase Greek letter alpha, a. Thermal diffusivity is defined as k/pCp, where k is the thermal conductivity, p is the density, and Cp is the heat capacity at constant pressure per unit mass. We will see in a moment why the term diffusivity is used to describe this parameter. We will generally confine our descriptions in this chapter to thermal conductivity. 

The proportionality constant, jx, is the viscosity. When the velocity gradient is cm/s cm, or simply s , we call it the shear rate because of the units of inverse time. Often, the lowercase Greek letter gamma with an overdot, y, is used to represent the shear rate, dvxidy. The shear stress of x-directed moment in the y direction, Xyx, typically has units of g/cm s. Hence, viscosity has cgs units of g/cm s, or poise. In the SI system, the unit of Pa s is often used. Note that 1 Pa s = 10 poise. In this chapter we will have a lot to say about viscosity and how it varies for different materials in their molten or liquid states. 

For a power-law fluid, the viscosity is now a function of shear rate. Often times, a non- Newtonian viscosity is designated with the lowercase Greek letter eta, rj, to differentiate it from a Newtonian viscosity, jr ... 

Matrix elements 5 are the overlap matrix elements we have seen before. For a general matrix element (we here adopt a convention that basis functions are indexed by lowercase Greek letters, while MOs are indexed by lower-case Roman letters) we compute... 

For an infinite set of data, the mean is designated by the lowercase Greek letter mu, p (the population mean), and the standard deviation is written as a lowercase Greek sigma, cr (the population standard deviation). We can never measure p and cr, but the values of x and 5 approach p and cr as the number of measurements increases. 

The lowercase Greek letter delta (5) is used to represent a partical charge. 

We generally denote scalars by lowercase Greek letters (e.g., P), column vectors by boldface lowercase Roman letters (e.g., x), and matrices by capital italic Roman letters (e.g., H). A superscriptT denotes a vector or matrix transpose. Thus xT is a row vector, xTy is an inner product, and AT is the transpose of the matrix A. Unless stated otherwise, all vectors belong to R , the u-dimen-sional vector space. Components of a vector are typically written as italic letters with subscripts (e.g., xux2,.. . , ). The standard basis vectors in R" are the n vectors ei,e2,. . . , e , where e has the entry 1 in the th component and 0 in all others. Often, the associated vector norm is the standard Euclidean norm, j 2, defined as... 

Pauling developed the concept of hybrid orbitals to describe the bonding in molecules containing second-period atoms with steric numbers 2, 3, and 4. Let s discuss these hybridization schemes in sequence, starting with BeH2. We will use the lowercase Greek letter chi, x, to represent hybrid orbitals. 

The names of modified carboxylic acids are often derived from the trivial names of the acids. Positions of substituents are sometimes indicated by lowercase Greek letters, beginning with the carbon adjacent to the carboxyl carbon, rather than by numbering the carbon chain. 

In systematic nomenclature, the position of a substituent is designated by a number. The carbonyl carbon of a carboxylic acid is always the C-1 carbon. In common nomenclature, the position of a substituent is designated by a lowercase Greek letter, and the carbonyl carbon is not given a designation. The carbon adjacent to the carbonyl carbon is the a-carbon, the carbon adjacent to the a-carbon is the jS-carbon, and so on. 

Solving Schrodinger s equation for the hydrogen atom leads to a series of mathematical functions called wave functions that describe the electron in an atom. These wave functions are usually represented by the symbol ip (lowercase Greek letter psi). Although the wave function has no direct physical meaning, the square of the wave function, provides information about the electron s location when it is in an allowed energy state. 

Figure 7.15 I When twop orbitals approach one another and overlap end to end, as shown here, they form a sigma bond. (This is sometimes denoted by the lowercase Greek letter sigma C7.)...

Another way of describing solution composition is the mole fraction (symbolized by the lowercase Greek letter chi, X), the ratio of the number of moles of a given component to the total number of moles of solution. For a two-component solution, where Ha and % represent the number of moles of the two components. 

There is no universally recognized system for the nomenclature of polymorphs. They are often labeled with Arabic (1, 2, 3,. . . ) or Roman (I, II, III, IV,. . . ) numerals, lowercase or uppercase Roman letters (a, b, c,. .. or A, B, C,. . . ) or lowercase Greek letters (a, (3, y,. . . ), or by names descriptive of properties (red form, low-temperature polymorph, metastable modification, etc.). If polymorphs are described by Roman numerals, it is a common convention to label the polymorph with the highest melting point with I, the one with the second highest with II, and so on. This notation vdll be used in this chapter. 

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