Mach number

When atoms are of similar atomic number (isotopes) they are arranged in decreasing mass number.  [c.356]

Oxide clusters are another class of important ionic clusters because of the important roles that oxide materials play in both chemical catalysis and advanced materials applications. Oxide clusters of the main group I-III elements are dominated by the electrostatic interactions [125, 126 and 127]. Oxide clusters of the transition metals become more complicated with both ionic and covalent characters [128]. Oxide clusters of the late main group elements, such as silicon, are more dominated by covalent bonding. Oxide clusters are relatively less well characterized. Chemical reactivity of a number of transition-metal oxide clusters has been studied in a fast flow reactor with laser vaporization [129]. Antimony and bismuth oxide clusters have been recently produced, and magic number clusters characteristic of bulk compositions are observed [130, 131]. Photoelectron spectroscopy of size-selected anions has been carried out on a number of oxide cluster series [126, 132, 133 and 134]. The electronic stmcture evolution from that of a bare cluster to that of an oxide is monitored as the cluster is oxidized step-by-step by oxygen. Figure Cl.1.7 shows the stmctures of a series of Si O (y = 1-6) clusters [134], which can be viewed as a sequential oxidation of a Si cluster. The local Si-0 bonding stmcture from Si O to Si O mimic that of the initial oxidation of a silicon surface, whereas the larger clusters (Si O to Si O ) with a SiO unit begins to mimic that of bulk silicon oxide.  [c.2398]

If two atoms have the same atomic number but different mass number, the atom with higher mass number comes first.  [c.79]

Mass number of mass spectra fragments  [c.555]

Nucleon number, mass number A  [c.81]

Kinetic energy K, T. Mass number A  [c.104]

Mach number Ma Molality b  [c.104]

Mass Number, Atomic Number, Number of Atoms, and Ionic Charge. The mass number, atomic number, number of atoms, and ionic charge of an element are indicated by means of four indices placed around the symbol  [c.213]

Each element that has neither a stable isotope nor a characteristic natural isotopic composition is represented in this table by one of that element s commonly known radioisotopes identified by mass number and relative atomic mass.  [c.224]

Nuclide. Each nuclide is identified by element name and the mass number A, equal to the sum of the numbers of protons Z and neutrons N in the nucleus. The m following the mass number (for example, Zn) indicates a metastable isotope. An asterisk preceding the mass number indicates that the radionuclide occurs in nature. Half-life. The following abbreviations for time units are employed y = years, d = days, h = hours, min = minutes, s = seconds, ms = milliseconds, and ns = nanoseconds.  [c.333]

Element Mass number Percent Element Mass number Percent  [c.356]

Element Mass number Percent Element Mass number Percent  [c.357]

Element Mass number Percent Element Mass number Percent  [c.358]

Element Mass number Percent Element Mass number Percent  [c.359]

Included in the table are all compounds for which information was available through the C, compounds. The mass number for the five most important peaks for each compound are listed, followed in each case by the relative intensity in parentheses. The intensities in all cases are normalized to the w-butane 43 peak taken as 100. Another method for expressing relative intensities is to assign the base peak a value of 100 and express the relative intensities of the other peaks as a ratio to the base peak. Taking ethyl nitrate as an example, the tabulated values would be  [c.816]

Atoms with the same number of protons but a different number of neutrons are called isotopes. To identify an isotope we use the symbol E, where E is the element s atomic symbol, Z is the element s atomic number (which is the number of protons), and A is the element s atomic mass number (which is the sum of the number of protons and neutrons). Although isotopes of a given element have the same chemical properties, their nuclear properties are different. The most important difference between isotopes is their stability. The nuclear configuration of a stable isotope remains constant with time. Unstable isotopes, however, spontaneously disintegrate, emitting radioactive particles as they transform into a more stable form.  [c.642]

The most important types of radioactive particles are alpha particles, beta particles, gamma rays, and X-rays. An alpha particle, which is symbolized as a, is equivalent to a helium nucleus, fHe. Thus, emission of an alpha particle results in a new isotope whose atomic number and atomic mass number are, respectively, 2 and 4 less than that for the unstable parent isotope.  [c.642]

When in addition to indicating fragmentation of the bond, it is necessary to emphasize the mass number of the fragments formed, this is done by writing the mass number at the top (right-hand fragment) or the bottom (left-hand fragment) as shown  [c.440]

Mass number of longest Hved or most available isotope.  [c.212]

The plutonium usually contains isotopes of higher mass number (Fig. 1). A variety of industrial-scale processes have been devised for the recovery and purification of plutonium. These can be divided, in general, into the categories of precipitation, solvent extraction, and ion exchange.  [c.213]

Mass number of longest Hved isotopes.  [c.225]

Comphcated theoretical calculations, based on filled shell (magic number) and other nuclear stabiUty considerations, have led to extrapolations to the far transuranium region (2,26,27). These suggest the existence of closed nucleon shells at Z = 114 (proton number) and N = 184 (neutron number) that exhibit great resistance to decay by spontaneous fission, the main cause of instabiUty for the heaviest elements. Eadier considerations had suggested a closed shell at Z = 126, by analogy to the known shell at = 126, but this is not now considered to be important.  [c.226]

Compressible Vlow. The flow of easily compressible fluids, ie, gases, exhibits features not evident in the flow of substantially incompressible fluid, ie, Hquids. These differences arise because of the ease with which gas velocities can be brought to or beyond the speed of sound and the substantial reversible exchange possible between kinetic energy and internal energy. The Mach number, the ratio of the gas velocity to the local speed of sound, plays a central role in describing such flows.  [c.94]

Phenomena analogous to shock waves in gases can occur in open-channel flow of Hquids. The Froude number, (j, is the ratio of fluid velocity to the velocity of a small surface wave, and plays the same role in open-channel flow as the Mach number does in compressible flow. Thus Hquid flowing under a sluice gate is often discharged at a shallow depth at high velocity, corresponding to a Froude number greater than unity. At a distance downstream, the Hquid is observed to undergo a hydraulic jump to a greater depth at a slower velocity, for which the Froude number is less than unity. The decreased Hquid momentum appears as greater pressure (depth). In contrast to the normal shock, a great deal of turbulence is generated at the jump because of the sudden lateral expansion, and energy is dissipated through friction.  [c.95]

Poisson s ratio at 125—375 K isotopes mass number natural abundance, %  [c.276]

Isotope mass number Abundance, % Thermal neutron cross Contribution to the total cross  [c.439]

Iodine [7553-56-2] I, atomic number 53, atomic weight 126.9044, is a nonmetaUic element belonging to the halogen family in Group 17 (VIIA) of the Periodic Table. The only stable isotope has a mass number of 127. There are 22 other iodine isotopes having masses between 117 and 139 14 of these isotopes yield significant radiation.  [c.358]

Lead, atomic number 82, is a member of Group 14 (IVA) of the Periodic Table. Ordinary lead is bluish grey and is a mixture of isotopes of mass number 204 (15%), 206 (23.6%), 207 (22.6%), and 208 (52.3%). The average atomic weight of lead from different origins may vary as much as 0.04 units. The stable isotopes are products of decay of three naturally radioactive elements (see Radioactivity, natural) comes from the uranium series (see Uraniumand  [c.32]

Descriptions of various MHD generator flow models can be found in the Hterature (28—30). A typical procedure for performing actual channel calculations (29) is to start by specifying the composition of the reactants, from which therm ochemical, thermodynamic, and electrical properties of the working fluid are generated (31). The principal input data required to proceed with the calculations are the total mass flow rate, the combustor stagnation pressure and enthalpy, and specified design conditions of magnetic field, electrical load parameter, and Mach number along the channel. It is implicitly assumed that the magnetic field can in fact be treated as a prescribed quantity, ie, it is not significantly influenced by the induced currents in the gas. More sophisticated, two- and three-dimensional computer codes have been developed to treat aspects of channel flow (32,33). Codes which can treat unsteady flows have also been developed for the analysis of end effects, transient flows, and flows with shock waves, and to determine conditions under which secondary flows or instabiUties may occur.  [c.418]

France M R, Buchanan J W, Robinson J C, Pullins S FI, Tucker J T, King R B and Duncan M A 1997 Antimony and bismuth oxide clusters growth and decomposition of new magic number clusters J. Phys. Chem. A 101 6214  [c.2407]

The streamline upwinding method is usually employed to obtain the discretized form of Equation (3.73). The solution algorithm in the ALE technique is similar to the procedure used for a fixed VOF method. In this technique, however, the solution found at the end of the nth time step, based on mesh number n, is used as the initial condition in a new mesh (i.e. mesh number n + 1). In order to minimize the error introduced by this approximation the difference between the mesh configurations at successive computations should be as small as possible. Therefore the time increment should be small. In general, adaptive or re-raeshing algorithms are employed to construct the required finite element mesh in successive steps of an ALE procedure (Donea, 1992). In some instances it is possible to generate the finite element mesh required in each step of the computation in advance, and store them in a file accessible to the computer program. This can significantly reduce the CPU time required for the simulation (Nassehi and Ghoreishy, 1998). An example in which this approach is used is given in Chapter 5.  [c.103]

Ernest O. Lawrence, inventor of the cyclotron) This member of the 5f transition elements (actinide series) was discovered in March 1961 by A. Ghiorso, T. Sikkeland, A.E. Larsh, and R.M. Latimer. A 3-Mg californium target, consisting of a mixture of isotopes of mass number 249, 250, 251, and 252, was bombarded with either lOB or IIB. The electrically charged transmutation nuclei recoiled with an atmosphere of helium and were collected on a thin copper conveyor tape which was then moved to place collected atoms in front of a series of solid-state detectors. The isotope of element 103 produced in this way decayed by emitting an 8.6 MeV alpha particle with a half-life of 8 s.  [c.215]

A subrule of the Cahn-Ingold-Prelog system specifies that higher mass number takes prece dence over lower when distinguishing between isotopes  [c.319]

Rule 1. Priority is assigned to atoms on the basis of atomic number. Higher priority is assigned to atoms of higher atomic number. If two atoms are isotopes of the same element, the atom of higher mass number has the higher priority. For example, in 2-butene, the carbon atom of each methyl group receives first priority over the hydrogen atom connected to the same carbon atom. Around the asymmetric carbon atom in chloroiodomethanesulfonic acid, the priority sequence is I, Cl, S, H. In 1-bromo-l-deuteroethane, the priority sequence is Cl, C, D, H.  [c.45]

Enhancing the prospects for the actual synthesis and identification of super-heavy nuclei is the fact that the calculations show the doubly magic nucleus 29 14 not to be a single long-lived specimen but to be a part of a lathei large "island of stability" in a "sea of spontaneous fission" (2,26,27). The grid lines of Figure 7 show "magic" numbers of protons or neutrons giving rise to exceptional stability. The doubly magic region at 82 protons and 126 neutrons is shown by a mountain a predicted doubly magic but less stable region at 114 protons and 184 neutrons is shown by a liHl at the island of stability. The ridges depict areas of enhanced stability due to a single magic number. Other calculations suggest that there should be stabilizing, deformed nuclear shells (or subsheUs) at lower neutron numbers, such as 77 = 162.  [c.226]

See pages that mention the term Mach number : [c.224]    [c.226]    [c.252]    [c.283]    [c.295]    [c.1452]    [c.351]    [c.214]    [c.96]    [c.213]    [c.349]    [c.395]    [c.583]    [c.565]    [c.425]   
Modern spectroscopy (2004) -- [ c.395 ]

Gas turbine engineering handbook (2002) -- [ c.0 ]

Compressors selections and sizing (1997) -- [ c.2 , c.4 , c.7 , c.26 , c.186 ]

Pressure safety design practices for refinery and chemical operations (1998) -- [ c.335 , c.337 ]

Industrial ventilation design guidebook (2001) -- [ c.1402 ]