A heat-pipe thermoelectric generator system is technically optimal to combined with other energy sources converting heat to electricity in multiple applications for its unique advanced features. This study addresses t...
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A heat-pipe thermoelectric generator system is technically optimal to combined with other energy sources converting heat to electricity in multiple applications for its unique advanced features. This study addresses the challenge of optimizing the efficiency and safety margin of the system by focusing on the critical multi-physical coupling performance between heat pipes and thermoelectric generators. Using an object-oriented approach with Modelica, we developed novel models-a heat pipe model integrating two-dimensional transient heat conduction with one-dimensional pressure equations and a thermoelectric generator model incorporating three thermoelectric effects and contact resistances. These models were validated against existing studies, showing general relative deviations less than 5%. Application to the NUSTER-100 system yielded results aligning with the findings in the reference and relative deviations around 5%, demonstrating feasibility and fidelity in simulating complex energy conversion systems under steady-state and transient conditions. The novelty lies in the comprehensive modeling of the coupled performance at the system level, enhancing understanding and application beyond previous isolated studies.
Nitrogen (N) and phosphorous (P) are key nutrients in eutrophication. This phenomenon has been mostly studied in lakes and reservoirs. Eutrophication could not be controlled in lakes and reservoirs due to water statio...
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Nitrogen (N) and phosphorous (P) are key nutrients in eutrophication. This phenomenon has been mostly studied in lakes and reservoirs. Eutrophication could not be controlled in lakes and reservoirs due to water stationarity. In order to mitigate the rate of eutrophication, we should determine specific points in a river reach and control the rate of eutrophication by implementing possible solutions. Also we should take into account as many as possible sources of nutrients entering into water bodies in a watershed scale including farm lands and waste water to determine the point of effect in decision-making. To reach this aim, an object-oriented modeling approach based on the concepts of system dynamics (SD) is used in this paper. It aims to build a model capable of considering dynamic feedback loops influencing the flow of nutrients in a watershed for managerial purposes. A watershed composed of different sub basins is set out as a system to configure its objects and their associations. Also physical rules are used as main equations to clarify the inter-relationships of different objects within the system. In this research, the qualitative feature refers to the amount of N and P parameters, which are the main factors of eutrophication phenomenon. The results of study show that the model is capable of estimating the value of discharge and the concentration of N and P in a river reach as well. The value of R-2 for both calibration and validation at Doab stations are 0.61, and 0.5 respectively. Also the value of R-2 is 0.73 and 0.65 for of N and P concentration, respectively.
Background and objective: We hypothesized that a biophysical computational model implemented in an object-oriented modeling language (OOML) would provide physiological information and simulative data to study the deve...
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Background and objective: We hypothesized that a biophysical computational model implemented in an object-oriented modeling language (OOML) would provide physiological information and simulative data to study the development and treatment of cardiogenic pulmonary congestion. Methods: This work is based on the object-oriented cardiopulmonary interaction introduced in [1]. This paper describes the novel model components required to study cardiogenic pulmonary congestion: i) interstitial fluid exchange related to the Starling equation, ii) the lymphatic pump, and iii) the interconnection of these elements with the original cardiopulmonary model. The presented model succeeds in i) describing lymphatic flow at the capillary artery and venous end, ii) activation of the lymphatic pump at elevated pulmonary pressures, and iii) the simulation of the different safety factors related to lung tissue, osmotic gradient, and the lymphatic system during the development of lung congestion. Results: Simulations show a qualitative correlation between model behavior and physiological data from literature. The model also demonstrates the beneficial effect of continuous positive airway pressure therapy on fluid clearance and respiratory mechanics. Conclusion: This study demonstrates the successful use of OOML to describe the development of cardiogenic congestion by introducing a model of the lymphatic system and the thoracic fluid balance system, as well as connecting them to the existing cardiopulmonary model. (C) 2019 Elsevier B.V. All rights reserved.
Are differential-algebraic equations the right tool for the object-oriented modeling of physical systems? One may say yes, given all the empirical evidence. However, this paper offers a brief reasoning from a fundamen...
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ISBN:
(纸本)9781450377133
Are differential-algebraic equations the right tool for the object-oriented modeling of physical systems? One may say yes, given all the empirical evidence. However, this paper offers a brief reasoning from a fundamental information-oriented perspective. The findings suggest that there are inherent flaws concerning the computational realization of DAEs in implicit form and that extensions are needed or alternatives should be investigated.
This paper discusses production scheduling problems on CNC-machines having a set of cutting tools in a Flexible Manufacturing System (FMS) to maximize the cutting tools utilization. This objective has been selected be...
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This paper discusses production scheduling problems on CNC-machines having a set of cutting tools in a Flexible Manufacturing System (FMS) to maximize the cutting tools utilization. This objective has been selected because it is frequently found that cutting tools are under-utilized as they are used far below their respective lifetime limits. We will consider the situation where several identical CNC-machines are operated in an FMS;each of which is equipped with the same cutting tool configuration. The jobs to be scheduled are machining parts, and each of the parts requires one to two stages of processes, and each of the stages consists of several sequential operations, where a specific operation requires a certain type of cutting tool. Whenever a certain cutting tool is being used, the time consumption will be accumulated to calculate its remaining lifetime. The assignment of an operation to a particular CNC-machine will be based on the sufficiency of the cutting tool remaining lifetime to complete the operation. We formulate the problem in a mathematical model and then solve it using a solution method based on the object-oriented modeling approach, where the FMS elements are grouped as classes of the objects, i.e. the CNC-machine, the cutting-tool, the product (job) and the storage classes. Numerical examples show that the proposed solution method can effectively solve the scheduling problem.
The limitations of the actual theoretical structure of occupational science are discussed emphasizing on its implications when dealing with the stability and sustainability of social systems. By using a literature rev...
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ISBN:
(纸本)9783319938189;9783319938172
The limitations of the actual theoretical structure of occupational science are discussed emphasizing on its implications when dealing with the stability and sustainability of social systems. By using a literature review focused on the time evolution and disciplinary distribution of the scientific production about human occupation, it is verified the insufficient production leading to the development of models that facilitate quantitative reasoning to support decision making. As an alternative, the architecture of an object-oriented framework is proposed. The framework is presented by using an UML (Unified modeling Language) class diagram of a generic occupational system, including the class model of each system's component: attributes and behaviors. Finally, guidelines are given for the use of the models produced with the framework in simulating diverse occupation systems scenarios.
This paper presents an object-oriented modeling (OOM) approach to model development of marine operation systems, specifically the hydraulic systems of marine cranes. Benefited from the rapid development of computation...
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This paper presents an object-oriented modeling (OOM) approach to model development of marine operation systems, specifically the hydraulic systems of marine cranes. Benefited from the rapid development of computation technology, many modeling and simulation techniques and software tools have proved to be very useful during the product and system development process. However, due to the increasing complexity of the physical systems, many challenges still exist regarding model flexibility, model integration, simulation accuracy, stability, and efficiency. The goal of introducing OOM to complex dynamic systems is to provide flexible, effective, and efficient models for different simulation applications. Previous work presented a virtual prototyping (VP) framework based on the functional mock-up interface (FMI) standard. The advantage of using FMI cosimulation is that modeling and simulation of stiff and strongly coupled systems can be distributed. As a result, the modeling tradeoffs between simulation accuracy and efficiency can be evaluated. The essential features of OOM and its application within dynamic operation system domain are highlighted through a case study. These features include model causality, model encapsulation, and inheritance that facilitate the decomposition and coupling of complex system models for co-simulation. The simulation results based on the proposed VP framework showed speedups in the computation efficiency at the cost of moderate accuracy loss.
Pesticides are toxic chemicals/products that are widely used for pest control. The most widely used type of pesticides is insecticides, fungicides and herbicides. Their continued use has been associated with undesired...
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Pesticides are toxic chemicals/products that are widely used for pest control. The most widely used type of pesticides is insecticides, fungicides and herbicides. Their continued use has been associated with undesired effects to non-target organisms thus raising environmental concerns worldwide. The problem however, is complex to integrate as there are number of processes that could contribute to the undesired effects. One of the problems is the lack of object-oriented and open source ecological tools that could be used to model the complex interaction of pesticides in the environment and their effects to non-target organisms e.g., frogs. Ecological models could save time as they could be used for management of complex interaction in the environment. The aim of the present study was therefore to add to the available literature, an ecological modeling tool that could be used to model this complex interaction of pesticides and the environment either for research or registration purposes. In this view, PestTox, which is an object-oriented and open-source model, was developed. The model is written in standard C + + language to model this complex interaction. PestTox adopted PestLCI model so that sub-models (objects) could be integrated to it. New equations for modeling washoff, photo-degradation, and pesticide-induced mortality rates were added to PestTox. The model runs on Linux, OS X, and Windows operating systems. It utilizes open source programs;Universal simulator, R, and Notepad, as such it remains open source. This model could be of interest to those involved in ecological modeling, modeling fate and transport of pesticides, data science, and management framework to evaluate potential effects of using pesticides in agricultural settings.
Dynamics of a multibody system is simulated in a most universal way in case of contacts having a compliance property. This latter case is implemented usually by elasticity / viscosity along the direction normal to the...
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ISBN:
(纸本)9788494690921
Dynamics of a multibody system is simulated in a most universal way in case of contacts having a compliance property. This latter case is implemented usually by elasticity / viscosity along the direction normal to the rigid body outer / inner surface and by friction along its tangent direction. The Hertz model is one of the most popular elastic contact models for engineering applications. object-oriented approach for building up the multibody dynamics model simulating compliant contacts is under development in this paper. A technology for constructing classes-templates is applied to build up contact objects in the dynamical model. The Hertz contact model is under consideration as a simplest example.
The work presented in this paper is the modeling of an information system supporting all activities of the reverse logistics(RL). In order to gather knowledge about the current state of the art on this topic, a litera...
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ISBN:
(纸本)9789897582349
The work presented in this paper is the modeling of an information system supporting all activities of the reverse logistics(RL). In order to gather knowledge about the current state of the art on this topic, a literature review is established for the available research works which are classified using a suitable criteria. Based on this review, our work consist of developing an information system (IS) design for reverse logistics (RL) management. The proposed modeling is based on an object-oriented analysis approach. The results announced at the analysis step includes the use case diagrams which modeling the dynamic aspect of the system with the actors interacting processes and a class diagram that models the key concepts of information managed in the system. This modeling is generic for a company which takes into account good practices in RL.
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