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Systems approach
Published in John M. Nicholas, Herman Steyn, Project Management for Engineering, Business and Technology, 2020
John M. Nicholas, Herman Steyn
Systems can be classified as closed or open. A closed system is one that is viewed as self contained with no interaction with its environment. “Closed-systems thinking” means to focus on the internal operation, structure, and processes of a system without regard to the environment. For some kinds of systems, closed-system thinking applies: to understand how a machine functions, you need only study the machine, its components, and not anything else. This does not mean that the environment does not affect the system but only that the person looking at the system has chosen to ignore the environment. For analyzing or improving the design of many kinds of mechanical systems, closed-system thinking works fairly well.
Cloud Computing, Data Sources and Data Centers
Published in Diego Galar Pascual, Pasquale Daponte, Uday Kumar, Handbook of Industry 4.0 and SMART Systems, 2019
Diego Galar Pascual, Pasquale Daponte, Uday Kumar
Threats to physical safety are not a new concern to OT teams; they’ve been implementing safety measures into industrial systems for decades. However, they’re currently facing threats that are potentially outside of their control. Taking machines and control systems out of a closed system brings the threat of hacked machines and the potential to injure employees (e.g., overheating, emergency shut-offs overridden, etc.).
Introduction to systems thinking
Published in D.R. Moore, D.J. Hague, Building Production Management Techniques, 2014
When a closed system structure is used the production system becomes incapable of change, and cannot respond to, or influence, its external environment. The actions of such a system are completely predictable and mechanistic. An example would be a closed system which required a functioning petrol driven internal combustion engine. In the event of petrol no longer being available, the closed system would not be able to respond by switching to some other fuel which was available, such as alcohol. Machines in general are seen as operating as closed systems. There is, however, an argument that this perception is insufficiently sophisticated and does not allow for the increasing application of artificial intelligence (AI) within machines. Certain areas of AI are becoming so sophisticated that the argument is no longer solely about whether or not machines are being discussed; there is growing discussion of artificial life (AL) (Levy 1992).
Understanding laser-metal interaction in selective laser melting additive manufacturing through numerical modelling and simulation: a review
Published in Virtual and Physical Prototyping, 2022
Abdelkrim Bouabbou, Sebastien Vaudreuil
Thermo-physical phenomena associated with SLM are driven by mass and heat transfer. Laser heating is extremely rapid due to the fast scanning laser velocities. Cooling rate is similarly high due to thermal convection, as well as evaporation of volatile elements during the interaction between metallic powder and circulating gas in the build chamber. This helps the powder bed release heat with a direct dependence on the surface temperature of the material. Due to heat conduction, the absorbed thermal energy is further distributed into the material and the temperature peak at the surface is reduced. This effect depends mainly on the thermal diffusivity of the material and what energy density is applied to the powder layer. In a closed system, with respect to the first law of thermodynamics, the energy balance equation is formulated as follows: where QL, QC, QCV and QR respectively are the laser heat flux quantity, conduction, convection and radiation heat quantities. Fourier’s law describes heat conduction according to the equation below:
Geometric theory of topological defects: methodological developments and new trends
Published in Liquid Crystals Reviews, 2021
Sébastien Fumeron, Bertrand Berche, Fernando Moraes
In many senses, cosmology consists in thermodynamics applied to the largest expanding closed system: our universe. Our current understanding of cosmic history is indeed based on the Standard Hot Big Bang Model and it originates in the pioneering works of three founding fathers: Albert Einstein, Alexander Friedman and George Lemaître. In essence, this model states that about 13.8 billion-years ago, the Universe was in an extremely hot dense state, consisting in a quark-gluon plasma, and that it has expanded ever since. In the framework of grand unified theory (GUT), the four fundamental interactions (the gravitational interaction, the electromagnetic interaction and two lesser-known forces, the weak nuclear interaction – responsible for radioactive β decays – and the strong nuclear interaction – which ensures the cohesion of the atomic nuclei) were then assumed to be unified at energy scales estimated at about GeV.
Extended MARTINI water model for heat transfer studies
Published in Molecular Physics, 2020
This section explains the validation of the new MARTINI-E model based on basics of energy balance. A CGMD model was shown in Figure 8(a) with dimensions of and liquid film thickness of at the centre with 2000 beads. This system is equilibrated for 500,000 steps at 373.15 K using a time step of 10 fs. This equilibrated system is then supplied with energy at a constant rate using a heat exchange algorithm [41]. According to energy balance of a closed system with no heat or work exchange with surroundings, the net heat input should be equal to net change in enthalpy.