scholarly journals Thermodynamic Model for Performance Analysis of a Stirling Engine Prototype

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2655 ◽  
Author(s):  
Miguel Torres García ◽  
Elisa Carvajal Trujillo ◽  
José Vélez Godiño ◽  
David Sánchez Martínez
Keyword(s):  
Heat Transfer ◽  
Decision Making ◽  
Stirling Engine ◽  
Decision Making Process ◽  
Actual Behavior ◽  
Isothermal Model ◽  
Working Cycle ◽  
Stirling Engines ◽  
Expected Values ◽  
The Ideal

In this study, the results of simulations generated from different thermodynamic models of Stirling engines are compared, including characterizations of both instantaneous and indicated operative parameters. The aim was to develop a tool to guide the decision-making process regarding the optimization of both the performance and reliability of Stirling engines, such as the 2.9 kW GENOA 03 unit—the focus of this work. The behavior of the engine is characterized using two different approaches: an ideal isothermal model, the simplest of those available, and analysis using the ideal adiabatic model, which is more complex than the first. Some of the results obtained with the referred ideal models deviated considerably from the expected values, particularly in terms of thermal efficiency, so a set of modifications to the ideal adiabatic model are proposed. These modifications, mainly related to both heat transfer and fluid friction phenomena, are intended to overcome the limitations due to the idealization of the engine working cycle, and are expected to generate results closer to the actual behavior of the Stirling engine, despite the increase in the complexity derived from the modelling and simulation processes.

Information Exchange (IE) Among Multi-Stakeholders for Improving Decision Making

2021 ◽  
Author(s):  
◽  
Ali Bazarah
Keyword(s):  
Decision Making ◽  
Information Exchange ◽  
Qualitative Evaluation ◽  
Decision Making Process ◽  
Actual Behavior ◽  
Good Theory ◽  
Multiple Stakeholders ◽  
Web Based ◽  
Mixed Methods Approach ◽  
Needed Information

Information Exchange (IE) is an important area of research in Information System (IS), yet there is a lack of theory that explains it. Existing studies usually borrow different theories from other fields to explain IE, but these theories describe the aspects that are associated with IE, not the actual behavior of IE. Additionally, a framework that guides the design of an IE platform to support IE among multiple stakeholders with the purpose of improving the decision-making process does not exist. To address these literature gaps, this dissertation first proposes a theory of Information Exchange (ToIE) to explain IE behavior and its impact on the decision-making process among multi-stakeholders. A qualitative evaluation of ToIE demonstrates that it meets the virtues of a good theory. Second, this dissertation develops an Information Exchange Decision Support (IEDS) framework that can guide the design of IE platforms for multiple stakeholders. The qualitative evaluation shows that the IEDS framework is useful for identifying the stakeholders, specifying the needed information to be exchanged, and maintaining the needed system factors necessary for IE. The IEDS framework is further instantiated to an IE platform named SES-IE. The SES-IE platform is a web-based application that facilitates the information exchange among scholarship organizations, employers, and students, and supports their decision-making process. The SES-IE platform was evaluated using a mixed-methods approach to measure the usability, usefulness, and satisfaction of the system. The successful instantiation of the SES-IE platform shows that the IEDS framework is useful for building an effective IE platform. This dissertation makes theoretical and practical contributions.

Optimization of Stirling Engine Performance Based on Multipoint Approximation Technique

1994 ◽  
Author(s):  
Vassili V. Toropov ◽  
Henrik Carlsen
Keyword(s):  
Computing Time ◽  
Engine Performance ◽  
Stirling Engine ◽  
Optimization Techniques ◽  
Approximation Technique ◽  
Working Cycle ◽  
Design Variables ◽  
Stirling Engines ◽  
Multipoint Approximation ◽  
Conventional Optimization

Abstract The ideal Stirling working cycle has the maximum obtainable efficiency defined by Carnot efficiency, and highly efficient Stirling engines can therefore be built, if designed properly. To analyse the power output and the efficiency of a Stirling engine, numerical simulation programs (NSP) have been developed, which solve the thermodynamic equations. In order to find optimum values of design variables, numerical optimization techniques can be used (Bartczak and Carlsen, 1991). To describe the engine realistically, it is necessary to consider several tens of design variables. As even a single call for NSP requires considerable computing time, it would be too time consuming to use conventional optimization techniques, which require a very large number of calls for NSP. Furthermore, objective and constraint functions of the optimization problem present some level of noise, i.e. can only be estimated with a finite accuracy. To cope with these problems, the multipoint explicit approximation technique is used.

From Public Reason to the Democratic Decision-Making Process

2018 ◽  
pp. 24-62
Author(s):  
Benjamin R. Hertzberg
Keyword(s):  
Decision Making ◽  
Public Reason ◽  
Political Influence ◽  
Decision Making Process ◽  
Public Justification ◽  
Religious Politics ◽  
Way Of Life ◽  
Political Approach ◽  
The Ideal

This chapter criticizes the ideal of public reason, showing that even when it is specified in several plausible ways, it does not provide citizens with sufficient guidance in evaluating religious politics. Instead, the ideal must be placed within a larger, way-of-life conception of democracy that considers religion’s roles in citizens’ civic lives. The chapter develops a minimal conception of public reason and analyses two criticisms of it: that public reason is a culturally protestant political approach that ignores crucial aspects of religion and that public reason violates religious citizens’ integrity. It then assesses two predominant responses to the second criticism: restricting the domain of public reason norms and adopting the convergence conception of public justification. Both responses demonstrate public reason’s inability to offer citizens sufficient guidance in evaluating religion’s political influence.

Innovation in Surgery: Qualitative Analysis of the Decision-Making Process and Ethical Concerns

2018 ◽  
Vol 25 (6) ◽  
pp. 586-593 ◽  
Author(s):  
Alban Zarzavadjian Le Bian ◽  
David Fuks ◽  
Renato Costi ◽  
Manuela Cesaretti ◽  
Audrey Bruderer ◽  
...  
Keyword(s):  
Decision Making ◽  
Qualitative Analysis ◽  
Ethical Dilemmas ◽  
Organ Transplant ◽  
Interaction Model ◽  
Decision Making Process ◽  
Surgical Innovation ◽  
Ethical Conflicts ◽  
Long Term Follow Up ◽  
The Ideal

Background. Surgical innovation from surgeon’s standpoint has never been scrutinized as it may lead to understand and improve surgical innovation, potentially to refine the IDEAL (Idea, Development, Exploration, Assessment, Long-term Follow-up) recommendations. Methods. A qualitative analysis was designed. A purposive expert sampling was then performed in organ transplant as it was chosen as the ideal model of surgical innovation. Interviews were designed, and main themes included the following: definition of surgical innovation, the decision-making process of surgical innovation, and ethical dilemmas. A semistructured design was designed to analyze the decision-making process, using the Forces Interaction Model. An in-depth design with open-ended questions was chosen to define surgical innovation and ethical dilemmas. Results. Interviews were performed in 2014. Participants were 7 professors of surgery: 3 in liver transplant, 2 in heart transplant, and 2 in face transplant. Saturation was reached. They demonstrated an intuitive understanding of surgical innovation. Using the Forces Interaction Model, decision leading to contemporary innovation results mainly from collegiality, when the surgeon was previously the main factor. The patient is seemingly lesser in the decision. A perfect innovative surgeon was described (with resiliency, legitimacy, and no technical restriction). Ethical conflicts were related to risk assessment and doubts regarding methodology when most participants (4/7) described ethical dilemma as being irrelevant. Conclusions. Innovation in surgery is teamwork. Therefore, it should be performed in specific specialized centers. Those centers should include Ethics and Laws department in order to integrate these concepts to innovative process. This study enables to improve the IDEAL recommendations and is a major asset in surgery.

Inclusion and Democracy. By Iris Marion Young. Oxford: Oxford University Press, 2000. 304p. $29.95.

2002 ◽  
Vol 96 (1) ◽  
pp. 200-201
Author(s):  
Barbara Cruikshank
Keyword(s):  
Decision Making ◽  
Democratic Theory ◽  
Decision Making Process ◽  
Oxford University ◽  
Iris Marion Young ◽  
Democratic Ideals ◽  
The Ideal ◽  
Oxford University Press

Engaging her contemporaries in debates over democratic ideals and processes, Iris M. Young offers a collection of seven essays that mitigate arguments on either side of those debates (participation vs. representation, localism vs. state, segregation vs. integration, identity vs. difference) by applying the critical ideal of inclusion. She argues that the normative legitimacy of democratic decisions rests upon the extent to which those affected by decisions are included in or have the opportunity to enter the decision making process. One might think that inclusion solves only one problem, the problem of exclusion, for democracy. However, Young extends the ideal of inclusion across manifold debates in democratic theory and speaks broadly to the less than ideal conditions under which we now practice democracy.

scholarly journals SISTEM PENDUKUNG KEPUTUSAN UNTUK MENENTUKAN POSISI PEMAIN IDEAL DALAM TIM SEPAK BOLA DENGAN METODE ALGORITMA GENETIKA

Compiler ◽  
2012 ◽  
Vol 1 (2) ◽  
Author(s):  
Hizkia Alprianta ◽  
Anton Setiawan Honggowibowo ◽  
Yuliani Indrianingsih
Keyword(s):  
Genetic Algorithm ◽  
Decision Making ◽  
User Interface ◽  
Interface Design ◽  
Selection Process ◽  
Decision Making Process ◽  
Media Processing ◽  
Ideal Position ◽  
The Right ◽  
The Ideal

So far, there are coaches who are less precise in determining the ideal position of the player as it only relies on instinct and the ego of the players so that there is still a coach who has not been able to objectively assess the players.By utilizing the method of Genetic Algorithm as Decision Support System (DSS) in the process of determining the ideal position of a player who uses several criteria (multicriteria) to choose a proper player. DSS is helping coach in making the right decisions and Genetic Algorithm is used as a model for multicriteria weighting in the selection process. This application was built with tools Borland Delphi (7.0) as the user interface design and media processing PostgreSQL as its database.            Based on these results we can conclude that this application expected to assist the coaches in the decision making process and can change the appraisal of which are subjective to more objective, to determine the ideal position for a player, can determine the best position of each position of a number of players and the expected results of the Genetic Algorithm on the system constructed in accordance with the results of manual calculations.

Preliminary Design and Adiabatic Analysis of a 3kW Free Piston Stirling Engine

2013 ◽  
Vol 325-326 ◽  
pp. 277-282 ◽  
Author(s):  
Chen Duan ◽  
Shui Ming Shu ◽  
Guo Zhong Ding ◽  
Ji Wei Yan
Keyword(s):  
Thermodynamic Analysis ◽  
Stirling Engine ◽  
Preliminary Design ◽  
Free Piston ◽  
Stirling Engines ◽  
Chp System ◽  
Free Piston Stirling Engine ◽  
The Ideal

In recent years, as one kind of Stirling engines, free piston Stirling engines are attracting world attention. Free piston Stirling engines could be applied to the solar dish system, micro-CHP system and so on. The development of a free piston Stirling engine is discussed in this paper. The ideal adiabatic model is used in the preliminary design of the free piston Stirling engine. The key parameters of the designed engine and the thermodynamic analysis are described in detail. Then the performance of the engine is obtained.

scholarly journals Dynamic Decision-Making Process of Evacuees during Post-Earthquake Evacuation near an Automatic Flap Barrier Gate System: A Broken Windows Perspective

2021 ◽  
Vol 13 (16) ◽  
pp. 8771
Author(s):  
Yu Song ◽  
Jia Liu ◽  
Qian Liu
Keyword(s):  
Decision Making ◽  
Critical Role ◽  
Emergency Evacuation ◽  
Dynamic Decision Making ◽  
Broken Windows ◽  
Decision Making Process ◽  
Force Model ◽  
Actual Behavior ◽  
Gate System ◽  
Crowd Evacuation

The automatic flap barrier gate system (AFBGS) plays a critical role in building security, but it is more vulnerable to natural hazards than common exits (including power failure, due to earthquakes, and delayed evacuation, due to safety certification, etc.). This article considers a dynamic decision-making process of evacuees during post-earthquake evacuation near an AFBGS. An interesting metaphor, broken windows (BW), is utilized to interpret people’s actual behavior during evacuation. A multi-stage decision-making mechanism of evacuees is developed to characterize the instantaneous transition among three defined stages: Habitual, mild, and radical states. Then, we build a modified three-layer social force model to reproduce the interaction between evacuees based on an actual post-earthquake evacuation. The simulations reveal that BW provides a contextualized understanding of emergency evacuation with a similar effect to the traditional metaphor. An earlier appearance of a mild rule breaker leads to a higher crowd evacuation efficiency. If evacuees maintain the state of broken windows behavior (BWB), the crowd evacuation efficiency can be improved significantly. Contrary to the criminological interpretation, the overall effect of mild BWB is positive, but the radical BWB is encouraged under the command of guiders.

scholarly journals Cyclic Control Optimization Algorithm for Stirling Engines

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 873
Author(s):  
Raphael Paul ◽  
Karl Heinz Hoffmann
Keyword(s):  
Optimal Control ◽  
Optimal Control Problem ◽  
Control Problem ◽  
Limit Cycles ◽  
Stirling Engine ◽  
Maximum Power ◽  
Maximum Efficiency ◽  
Engine Model ◽  
Stirling Engines ◽  
The Ideal

The ideal Stirling cycle describes a specific way to operate an equilibrium Stirling engine. This cycle consists of two isothermal and two isochoric strokes. For non-equilibrium Stirling engines, which may feature various irreversibilities and whose dynamics is characterized by a set of coupled ordinary differential equations, a control strategy that is based on the ideal cycle will not necessarily yield the best performance—for example, it will not generally lead to maximum power. In this paper, we present a method to optimize the engine’s piston paths for different objectives; in particular, power and efficiency. Here, the focus is on an indirect iterative gradient algorithm that we use to solve the cyclic optimal control problem. The cyclic optimal control problem leads to a Hamiltonian system that features a symmetry between its state and costate subproblems. The symmetry manifests itself in the existence of mutually related attractive and repulsive limit cycles. Our algorithm exploits these limit cycles to solve the state and costate problems with periodic boundary conditions. A description of the algorithm is provided and it is explained how the control can be embedded in the system dynamics. Moreover, the optimization results obtained for an exemplary Stirling engine model are discussed. For this Stirling engine model, a comparison of the optimized piston paths against harmonic piston paths shows significant gains in both power and efficiency. At the maximum power point, the relative power gain due to the power-optimal control is ca. 28%, whereas the relative efficiency gain due to the efficiency-optimal control at the maximum efficiency point is ca. 10%.

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