scholarly journals Definition of Heat in Open Systems

1980 ◽  
Vol 33 (1) ◽  
pp. 95 ◽  
Author(s):  
DA Smith
Keyword(s):  
Heat Flux ◽  
Heat Flow ◽  
Open Systems ◽  
Irreversible Thermodynamics ◽  
Equilibrium Thermodynamics ◽  
Domain Of Applicability ◽  
Usual Concept ◽  
Closed Systems ◽  
Adiabatic Processes ◽  
Definition Of

Existing definitions of heat in open systems are considered with the aim of providing acceptable physical motivation in restricted circumstances. The extent to which these definitions are independent of the usual concept of heat in closed systems is clarified: they all have the feature that internal energy may be transferred by convection in workless adiabatic processes. The global definitions are compared with various definitions of heat flux in irreversible thermodynamics. As the domain of applicability of these definitions is wider than that of equilibrium thermodynamics, it is suggested that a minimal check for any definition of heat flux be that it agree with the global definition of heat flow between equilibrium states in as wide a range of circumstances as possible.

Extended Irreversible Thermodynamics Versus Second Law Analysis of High-Order Dual-Phase-Lag Heat Transfer

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Hossein Askarizadeh ◽  
Hossein Ahmadikia
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Flow ◽  
Irreversible Thermodynamics ◽  
High Order ◽  
Second Law ◽  
Phase Lag ◽  
Dual Phase ◽  
Heat Transfer Equation ◽  
Extended Irreversible Thermodynamics

This study introduces an analysis of high-order dual-phase-lag (DPL) heat transfer equation and its thermodynamic consistency. The frameworks of extended irreversible thermodynamics (EIT) and traditional second law are employed to investigate the compatibility of DPL model by evaluating the entropy production rates (EPR). Applying an analytical approach showed that both the first- and second-order approximations of the DPL model are compatible with the traditional second law of thermodynamics under certain circumstances. If the heat flux is the cause of temperature gradient in the medium (over diffused or flux precedence (FP) heat flow), the DPL model is compatible with the traditional second law without any constraints. Otherwise, when the temperature gradient is the cause of heat flux (gradient precedence (GP) heat flow), the conditions of stable solution of the DPL heat transfer equation should be considered to obtain compatible solution with the local equilibrium thermodynamics. Finally, an insight inspection has been presented to declare precisely the influence of high-order terms on the EPRs.

Definition of the Temperature and Heat Flux in Micromilling of Hardened Steel Using the Finite Element Method

2014 ◽  
Vol 39 (10) ◽  
pp. 7229-7239 ◽  
Author(s):  
Sergio Luiz Moni Ribeiro Filho ◽  
Marcelo Oliveira Gomes ◽  
Carlos Henrique Lauro ◽  
Lincoln Cardoso Brandão
Keyword(s):  
Finite Element Method ◽  
Heat Flux ◽  
Finite Element ◽  
Hardened Steel ◽  
The Finite Element Method ◽  
Definition Of ◽  
Element Method

scholarly journals Expansion of the Range of Refrigeration of the Surface Heat Flow Unit Under Conductive Energy Produce

2018 ◽  
pp. 27-32
Author(s):  
S. Kovtun
Keyword(s):  
Heat Flux ◽  
Heat Flow ◽  
Flux Density ◽  
Heat Flux Density ◽  
Dynamic Range ◽  
Density Measurement ◽  
Lower Boundary ◽  
Surface Heat ◽  
Total Uncertainty ◽  
Unit Of Measurement

The article presents the results of investigations of factors that influence the accuracy of reproduction of the unit of measurement of the surface density of the heat flow by conductivity. Components of the uncertainty of the surface heat flux density measurement were analyzed using the Ishikawa cause-and-effect diagram, as shown in Fig. 1 The mathematical model of the method of reproduction of the unit of measurement was obtained, which takes into account the influence of the sources of uncertainty by making the corresponding corrections. The possibility of extending the lower boundary of the dynamic range by the correction of the factors having the greatest influence is substantiated. The rationale is based on the estimation of the uncertainty of the individual components, which, in the course of the correction of their impact, should not exceed the values (achieved to date). As an example, the calculation of the total uncertainty in the reproduction of the heat flux density of 20 W·m-2 is given. Table 1 contains all data important for the uncertainty analysis such as input quantities, their estimated values as well as the associated sensitivity coefficients and the variances determined.

Expertise as a Form of Knowledge: A Response to Quast

2020 ◽  
Vol 42 (2) ◽  
pp. 431-442
Author(s):  
Steve Fuller
Keyword(s):  
Social Epistemology ◽  
Open Systems ◽  
Epistemic Standard ◽  
Closed Systems ◽  
The Difference

Abstract Christian Quast has presented what he describes as a ‘role-functional’ account of expertise as a form of knowledge that purports to take into account prior discussions within recent analytic social epistemology and allied fields. I argue that his scrupulousness results in a confused version of the role-functional account, which I try to remedy by presenting a ‘clean’ account that clearly distinguishes such an account from what Quast calls a ‘competence-driven’ one. The key point of my account is that ‘competence’ pertains to knowledge in closed systems and ‘expertise’ in open systems. I observe that the invocation of ‘reliability’ as an epistemic standard simply serves to confuse the difference between the competence-driven and role-functional accounts.

6. Such quantities of sand

2014 ◽  
pp. 102-117
Author(s):  
Christopher Hall
Keyword(s):  
Carbon Dioxide ◽  
Circular Economy ◽  
Carbon Dioxide Emissions ◽  
Energy Supply ◽  
Open Systems ◽  
Human History ◽  
Material Flows ◽  
Material Resources ◽  
World Energy ◽  
Closed Systems

‘Such quantities of sand’ looks at sustainability and considers three features of the global materials system that need fixing: carbon dioxide emissions, world energy supply, and finite material resources. All societies, however diverse, are comprehensively and universally dependent on material artefacts. The scale of global material flows is enormous, and now greater than for all of human history. In a finite world, there are limits and so it is wise, on some timescale, to favour a circular economy of closed systems (repair, re-use, recycle) over open systems (extract, make, use, discard). Whatever else we do, it helps if we reduce the rate of flow of materials through the economy (use less, use longer).

Investigating the Mixing Efficiencies of Liquid-to-Liquid Chemical Injection Manifolds for Aquatic Invasive Species Management

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Thomas J. Zolper ◽  
Aaron R. Cupp ◽  
David L. Smith
Keyword(s):  
Invasive Species ◽  
Large Scale ◽  
Open Systems ◽  
Mixing Time ◽  
Water Injection ◽  
The United States ◽  
Aquatic Invasive Species ◽  
Chemical Treatments ◽  
Invasive Organisms ◽  
Closed Systems

Aquatic invasive species (AIS) have spread throughout the United States via major rivers and tributaries. Locks and dams positioned along affected waterways, specifically lock chambers, are being evaluated as potential management sites to prevent further expansion into new areas. Recent research has shown that infusion of chemicals (e.g., carbon dioxide) into water can block or kill several invasive organisms and could be a viable option at navigational structures such as lock chambers because chemical infusion would not interfere with vessel passage or lock operation. Chemical treatments near lock structures will require large-scale fluid-mechanic systems and significant energy. Mixing must extend to all stagnation regions within a lock structure to prevent the passage of an invasive fish. This work describes the performance of both wall- and floor-based CO2-infused-water to water injection manifolds targeted for lock structures in terms of mixing time, mixing homogeneity, injection efficiency, and operational power requirements. Both systems have strengths and weaknesses so selection recommendations are given for applications such as open systems and closed systems.

scholarly journals Open Prebiotic Environments Drive Emergent Phenomena and Complex Behavior

Life ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 45 ◽  
Author(s):  
Nathaniel Wagner ◽  
David Hochberg ◽  
Enrique Peacock-Lopez ◽  
Indrajit Maity ◽  
Gonen Ashkenasy
Keyword(s):  
Open Systems ◽  
Complex Behavior ◽  
Working Models ◽  
Emergent Phenomena ◽  
Systems Chemistry ◽  
Wide Range ◽  
Closed Systems ◽  
Prebiotic Environments ◽  
Far From Equilibrium ◽  
And Function

We have been studying simple prebiotic catalytic replicating networks as prototypes for modeling replication, complexification and Systems Chemistry. While living systems are always open and function far from equilibrium, these prebiotic networks may be open or closed, dynamic or static, divergent or convergent to a steady state. In this paper we review the properties of these simple replicating networks, and show, via four working models, how even though closed systems exhibit a wide range of emergent phenomena, many of the more interesting phenomena leading to complexification and emergence indeed require open systems.

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