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Operating Wisely
Published in Carl Bozzuto, Boiler Operator's Handbook, 2021
Another measure that confuses operators is mass. Mass is the amount of matter in an object. It is what one weighs at sea level under the influence of the earth’s gravity. If one is sent to Cape Kennedy, loaded into the space shuttle, sent up in space, and is then asked to stand on a scale and tell what it reads, it would be zero. With nearly zero gravity, there is no weight. However, one still has the same amount of mass that was weighed at sea level. There is a difference in weight with a change in altitude. One would weigh less in Denver, CO, USA because it is a mile higher. For all practical purposes, the small difference is not important to boiler operators. Once the fact that mass and weight have the same number on the surface of the earth is accepted (with some adjustment required for precision at higher elevations), one can accept that a pound mass weighs a pound and let it go at that.
Dynamic proper ties of soil
Published in Hsai-Yang Fang, John L. Daniels, Introductory Geotechnical Engineering, 2017
Hsai-Yang Fang, John L. Daniels
Kinematics deals with motion, that is, with time–displacement relationships and the geometry of movements. Kinetics considers the forces that produce or resist motion. From Newtonian physics the simple definition of mechanical force is equal to mass × acceleration. Mass is the measure of the property of inertia, which is what causes an object to resist change in its state of motion. Mass is weight, which is the force defined as W = mξ, where ξ = constant acceleration of gravity 9.81 m/s2 (32.2 ft/sc2). The use of equivalent static effects permits simpler analysis and design by obviating the need for a more complicated dynamic analysis. To make this possible the load effects and the structure’s responses must be translated into static terms. For example, (a) for earthquake effects the primary translation consists of establishing a hypothetical horizontal static force that is applied to a structure to simulate the effects of sideward motions during ground movements; (b) for wind load the primary translation consists of converting the kinetic energy of the wind into an equivalent static pressure, which is then treated in a manner similar to that for a distributed gravity load; and (c) for moving traffic load it can translate all types of moving vehicle loads into an equivalent 18-kip static load.
G
Published in Splinter Robert, Illustrated Encyclopedia of Applied and Engineering Physics, 2017
[general] Unit of mass, whereas weight is a function of gravitational acceleration. Mass is a quantification of the amount of matter in an object. Even though the gram is elementary, the use of the kilogram (kg) is the international standard. The mass of a platinum–iridium cylinder (height = 39 mm; diameter = 39 m), held at the International Bureau of Weights and Measures is the recognized standard for 1 kg. A set of 40 virtually identical cylinders (slight errors in reproduction, even though the dimensions can be verified with extremely high degree of accuracy, on a wavelength basis) were produced and distributed to regional calibration stations (in the United States the National Institute of Standards and Technology in Boulder, Colorado). Due to the inherent difficulties associated with measuring the mass of a single atom this has still not evolved into a easily reproducible measure and remains the only artificial standard.
Damage identification of thin plates using multi-stage PSOGSA and incomplete modal data
Published in Applied Mathematics in Science and Engineering, 2022
One of the recently developed population-based searched algorithms is GSA, which is developed by utilizing the idea of the gravitational laws and Newtonian laws of motion. It is a population-based method, each and every agent of the population is a potential candidate for the solution and is referred to as an object. The performance of each object is mainly determined by its mass. Each and every mass of the population follows the gravitational law and attract each other. The heavier mass will generate more attraction force towards other objects. Thus, the heaviest masses will have the best chance to reach the closest position to the global minimum, and it will attract other masses to that location according to their mass and distances. The mathematical formulation is as follows.
An improved multi-leader comprehensive learning particle swarm optimisation based on gravitational search algorithm
Published in Connection Science, 2021
Alfred Adutwum Amponsah, Fei Han, Jeremiah Osei-Kwakye, Ernest Bonah, Qing-Hua Ling
The basic GSA, established by (Rashedi et al., 2009) is a stochastic optimisation algorithm inspired by Newton’s laws of gravity and motion. In GSA, agents are referred to as objects and each object has its mass. Objects with greater mass produce a greater intensity of attraction. Hence, all other objects move towards the heaviest object by an interval of time. Agents are initialised with positions xi=(xi1, … ,xid, … ,xiD) and move through the search space with velocity vi = (vi1,vi2, … ..,viD). The mass of each agent is calculated by its fitness in (6) and (7) as, where fitit and Mit represent the fitness and the mass of the ith agent at the current tth iteration respectively. For minimisation, bestt and worstt are defined in (8) and (9), respectively.
Effects of upper and lower body wearable resistance on spatio-temporal and kinetic parameters during running
Published in Sports Biomechanics, 2020
Grace A. Couture, Kim D. Simperingham, John B. Cronin, Anna V. Lorimer, Andrew E. Kilding, Paul Macadam
All loading conditions, excluding WB10%, failed to elicit significant differences in spatio-temporal variables compared to ULPre. Despite LB loading at a wider range of loads, the present study showed no increase in SL. This opposes the findings of Martin (1985) who divided and applied a 1.0-kg load (1.4% BM) to each foot, while in the current study load (LB1% 0.6–0.9 kg; LB3% 1.8–2.7 kg; LB5% 3.0–4.5 kg) was evenly distributed around the thighs and shank, not centralised to the feet. When Martin (1985) applied the same load to the thigh, no spatio-temporal differences were observed. Inertia refers to the tendency of an object to resist changes in their current state, static or moving. Adding mass to an object will increase its inertia, requiring more energy to start or stop motion. Half a kilogram added to the thigh increased inertia for the leg about the hip approximately 2%, while adding the same load to the feet increased inertia by 13% (Martin, 1985). In contrast, LB loading in the present study was designed to retain limb balance and minimise inertial effects. Therefore, the varying inertial effect created by load placement could explain the differences between the results of this study and those of Martin (1985), despite the higher loading used.