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Aerosols
Published in Efstathios E. Michaelides, Clayton T. Crowe, John D. Schwarzkopf, Multiphase Flow Handbook, 2016
Yannis Drossinos, Christos Housiadas
where N is the number of primary particles that form the agglomerate df is the fractal (or Hausdor ) dimension kf is the fractal prefactor (also referred to as lacunarity (Lapuerta et al., 2010) or structure factor (Gmachowski, 1996)) Rg is the radius of gyration a1 is the radius of the primary particles e fractal dimension provides a quantitative measure of the degree to which a structure lls physical space beyond its topological dimension: a compact three-dimensional structure has df = 3, whereas a line df = 1. e fractal prefactor, a parameter whose importance is increasingly being appreciated (Wu and Friedlander, 1993, Gmachowski, 1996, Sorensen and Roberts, 1997), is an essential ingredient of a complete description of power-law aggregates, as suggested by the scaling law. e radius of gyration is a geometric measure of the spatial mass distribution about the aggregate center of mass. For N identical, spherical monomers, it may be calculated via
Development and initial results of an autonomous sailing drone for oceanic research
Published in Pentti Kujala, Liangliang Lu, Marine Design XIII, 2018
U. Dhomé, C. Tretow, J. Kuttenkeuler, F. Wängelin, J. Fraize, M. Fürth, M. Razola
The arrangement with main wing and flap typically causes a non-favorable mass distribution where center of mass is aft from the rotational axis. At nonzero heeling angles this leads to unwanted rig rotation due to the influence of gravity. The wing is balanced by adding mass on a rod extending in front of the rotation axis. However, this comes at the cost of higher center of gravity and larger moment of inertia, which in turn could increase the risk for roll-yaw-sway coupled dynamic instability phenomena. Such excitation has been clearly observed in the Vane experiments, as described further in this paper.
A Verification of the multi-body dynamics based on impulse-based method
Published in Ömer Aydan, Takashi Ito, Takafumi Seiki, Katsumi Kamemura, Naoki Iwata, 2019 Rock Dynamics Summit, 2019
The center of mass Xrb is decided by the mass distribution, so it is expressed as: Xrb=∑mixiM
Dynamic Magnification Factor of Pile-Supported Wharf under Horizontally Bi-Directional Ground Motion
Published in Journal of Earthquake Engineering, 2021
Shufei Gao, Jinxin Gong, Yunfen Feng
A regular marginal wharf with constant transverse width and configuration of piles is graphically illustrated in Figure 1. With reference to Figure 1, the segment length is and B is the width. The wharf seismic mass per unit longitudinal length and wharf lateral stiffness per unit longitudinal length are considered to be constant. The mass distribution in the transverse direction is approximately assumed to be uniform, which means the distance of center of mass from landside edge is . The eccentricity between center of mass and center of rigidity D is determined based on the elastic response when the landside piles with minimum deck-to-dike clearance reach yield displacement. The origin of coordinate system is located at the landside end of segment, as shown in Figure 1.
High-resolution spectroscopy near the continuum limit: the microwave spectrum of trans-3-bromo-1,1,1,2,2-pentafluoropropane
Published in Molecular Physics, 2019
Frank E. Marshall, Nicole Moon, Thomas D. Persinger, David J. Gillcrist, Nelson E. Shreve, William C. Bailey, G. S. Grubbs II
Second moments are a measure of the mass distribution about each axis. They are also referred to as planar moments because they are effectively a measure of the out-of-plane contribution to the mass. This means the out-of-ab-plane mass can be measured by . This is determined to be 91.47455(3) uÅ2 for the79Br isotopologue. Using the second-moment arguments of Bohn [39], the average value for for CF/CF groups is approximately 45 uÅ2. For CH/CH, the average value is 1.6 uÅ2. Because the molecule has a CF, a CF, and a CH group (ignoring the bromine which is in the plane), this gives a predicted value based on average second moments of 91.6 uÅ2, which is closer to the determined value, but overestimates it, than the quantum chemical calculations, which underestimates the value slightly and produced rotational constants to within 1% of experimentally determined values. This is further evidence that the presented calculated structure is close enough to the experimental structure to be considered as a very suitable substitute.
A Simplified Model to Evaluate the Dynamic Rocking Behavior of Irregular Free-Standing Rigid Bodies Calibrated with Experimental Shaking-Table Tests
Published in Journal of Earthquake Engineering, 2019
Cesar Arredondo, Miguel A. Jaimes, Eduardo Reinoso
Figure 1 provides some examples of objects whose irregularity, poor anchorage, or free-standing condition make them vulnerable to earthquakes; from rocks precariously placed in free field, to contents in strategic infrastructures, concrete gravity structures, lift-off of rigid foundations, weakly restrained walls with openings, multi-drum columns, tombstones, art objects, and electrical and mechanical equipment until storage furniture (shelves, racks, cabinets). They are normally analyzed using simplified 2D models of a single equivalent regular prismatic rigid body on a horizontal surface, as it is reported by several authors [Yim et al., 1980; Ishiyama, 1982; Shenton and Jones, 1991a, b; Makris and Roussos, 1998]. Common assumptions adopted in these studies are: (a) monolithic or invariable condition, (b) permanent contact with plane/rigid support surfaces (not bounce on impact), (c) simplified rectangular geometries and shapes, (d) equivalent height for complex objects neglecting the slenderness dependence on width-height ratio, (e) inaccurate analysis of visual orthogonal sections, representing the object by only one rectangular rigid block even in the case of irregular conditions (where at least two blocks are required), (f) constant interface friction and restitution coefficients, (g) irregular contents modeled as regular blocks, and (h) uniform mass distribution.