scholarly journals Generalized and Stability Rational Functions for Dynamic Systems of Reactor Kinetics

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Ahmed E. Aboanber
Keyword(s):  
Dynamic Systems ◽  
Nuclear Reactor ◽  
High Efficiency ◽  
Rational Functions ◽  
Neutron Density ◽  
Time Saving ◽  
General Validity ◽  
Reactor Kinetics ◽  
Stiff Ordinary Differential Equations ◽  
Different Types

The base of reactor kinetics dynamic systems is a set of coupled stiff ordinary differential equations known as the point reactor kinetics equations. These equations which express the time dependence of the neutron density and the decay of the delayed neutron precursors within a reactor are first order nonlinear and essentially describe the change in neutron density within the reactor due to a change in reactivity. Outstanding the particular structure of the point kinetic matrix, a semianalytical inversion is performed and generalized for each elementary step resulting eventually in substantial time saving. Also, the factorization techniques based on using temporarily the complex plane with the analytical inversion is applied. The theory is of general validity and involves no approximations. In addition, the stability of rational function approximations is discussed and applied to the solution of the point kinetics equations of nuclear reactor with different types of reactivity. From the results of various benchmark tests with different types of reactivity insertions, the developed generalized Padé approximation (GPA) method shows high accuracy, high efficiency, and stable character of the solution.

scholarly journals The Use of a Simulation Model for High-Runner Strategy Implementation in Warehouse Logistics

2020 ◽  
Vol 12 (23) ◽  
pp. 9818
Author(s):  
Gabriel Fedorko ◽  
Vieroslav Molnár ◽  
Nikoleta Mikušová
Keyword(s):  
Genetic Algorithm ◽  
Simulation Model ◽  
Optimization Problem ◽  
Software Tool ◽  
Time Saving ◽  
General Validity ◽  
Resistance Function ◽  
Genetic Algorithm Method ◽  
Working Day ◽  
Enterprise Logistics

This paper examines the use of computer simulation methods to streamline the process of picking materials within warehouse logistics. The article describes the use of a genetic algorithm to optimize the storage of materials in shelving positions, in accordance with the method of High-Runner Strategy. The goal is to minimize the time needed for picking. The presented procedure enables the creation of a software tool in the form of an optimization model that can be used for the needs of the optimization of warehouse logistics processes within various types of production processes. There is a defined optimization problem in the form of a resistance function, which is of general validity. The optimization is represented using the example of 400 types of material items in 34 categories, stored in six rack rows. Using a simulation model, a comparison of a normal and an optimized state is realized, while a time saving of 48 min 36 s is achieved. The mentioned saving was achieved within one working day. However, the application of an approach based on the use of optimization using a genetic algorithm is not limited by the number of material items or the number of categories and shelves. The acquired knowledge demonstrates the application possibilities of the genetic algorithm method, even for the lowest levels of enterprise logistics, where the application of this approach is not yet a matter of course but, rather, a rarity.

Investigation of Fuel Burnup Impacts on Nuclear Reactor Safety Parameters in the Canadian Pressure Tube Supercritical Water-Cool Reactor

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Ahmad Moghrabi ◽  
David Raymond Novog
Keyword(s):  
Nuclear Reactor ◽  
High Efficiency ◽  
Fission Products ◽  
Neutron Cross Section ◽  
Fuel Mixture ◽  
Pressure Tube ◽  
Candu Reactors ◽  
Safety Parameters ◽  
Nuclear Reactor Safety ◽  
The Impact

The Canadian pressure-tube super critical water-cooled reactor (PT-SCWR) is an advanced generation IV reactor concept which is considered as an evolution of the conventional Canada Deuterium Uranium (CANDU) reactor that includes both pressure tubes and a low temperature and pressure heavy water moderator. The Canadian PT-SCWR fuel assembly utilizes a plutonium and thorium fuel mixture with supercritical light water coolant flowing through the high-efficiency re-entrance channel (HERC). In this work, the impact of fuel depletion on the evolution of lattice physics phenomena was investigated starting from fresh fuel to burnup conditions (25 MW d kg−1 [HM]) through sensitivity and uncertainty analyses using the lattice physics modules in standardized computer analysis for licensing evaluation (SCALE). Given the evolution of key phenomena such as void reactivity in traditional CANDU reactors with burnup, this study focuses on the impact of fission products, 233U breeding, and minor actinides on fuel performance. The work shows that the most significant change in fuel properties with burnup is the depletion of fission isotopes of Pu and the buildup of high-neutron cross section fission products, resulting in a decrease in cell k∞ with burnup as expected. Other impacts such as the presence of protactinium and uranium-233 are also discussed. When the feedback coefficients are assessed in terms of reactivity, there is considerable variation as a function of fuel depletion; however, when assessed as Δk (without normalization to the reference reactivity which changes with burnup), the net changes are almost invariant with depletion.

scholarly journals Concrete Modular Pavements – Types, Issues And Challenges

2019 ◽  
Vol 14 (1) ◽  
pp. 80-103 ◽  
Author(s):  
Audrius Vaitkus ◽  
Judita Gražulytė ◽  
Rita Kleizienė ◽  
Viktoras Vorobjovas ◽  
Ovidijus Šernas
Keyword(s):  
Traffic Congestion ◽  
Road Network ◽  
Load Transfer ◽  
Precast Concrete ◽  
Concrete Slabs ◽  
Time Saving ◽  
Urban Streets ◽  
The Road ◽  
Different Types ◽  
Pavement Construction

According to the European Asphalt Pavement Association, more than 90 per cent of the European road network is paved with asphalt. Constantly increasing traffic volume and climate change accelerate deterioration of current pavements. As a result, there arises a need to rehabilitate them prematurely. Repair and rehabilitation work lead to traffic congestion, which is one of the most significant concerns in highly trafficked roads and urban streets. Concrete modular pavements consisting of precast concrete slabs are a reasonable solution to deal with the road works since their construction, as well as repair, is time-saving. Repair works typically are implemented during a low traffic period (usually at night). A primary purpose of concrete modular pavements is heavily trafficked roads and other transport areas. This paper focuses on concrete modular pavements, their types, issues and challenges related to their design, slab fabrication and pavement construction. The conducted analysis revealed 15 different types of concrete modular pavements that differ from the techniques of slab joints and load transfer between the adjacent slabs. More than 20 issues and challenges related to the design of modular elements, slab fabrication and pavement construction were identified. Finally, the existing practice of concrete modular pavements was summarised and the gaps of scientific knowledge, as well as a need for comprehensive research, were defined.

scholarly journals LISMA_HDS language for modeling heterogeneous dynamic systems

2021 ◽  
pp. 103-122
Author(s):  
Evgeny Popov ◽  
◽  
Yury Shornikov ◽  
Keyword(s):  
Dynamic Systems ◽  
Initial Value Problems ◽  
Method Of Lines ◽  
System Of Equations ◽  
Modeling Languages ◽  
Cauchy Problems ◽  
Systems Of Equations ◽  
Initial Value ◽  
Algebraic Systems ◽  
Different Types

Heterogeneous dynamic systems (HDS) simultaneously describe processes of different physical nature. Systems of this kind are typical for numerous applications. HDSs are characterized by the following features. They are often multimode or hybrid systems. In general, their modes are defined as initial value problems (Cauchy problems) for implicit differential-algebraic systems of equations. Due to the presence of heterogeneous dynamic components or processes evolving in both time and space, the dimension of the complete system of equations may be pretty high. In some cases, the system of equations has an internal structure, for instance, the differential-algebraic system of equations approximating a partial differential equation by the method of lines. An original huge system of equations can then be algorithmically rewritten in a compact form. Moreover, heterogeneous hybrid dynamical systems can generate events of qualitatively different types. Therefore one has to use different numerical event detection algorithms. Nowadays, HDSs are modeled and simulated in computer environments. The modeling languages widely used by engineers do not allow them to fully specify all the properties of the systems of this class. For instance, they do not include event typing constructs. That is why a declarative general-purpose modeling language named LISMA_HDS has been developed for the computer-aided modeling and ISMA simulation environment. The language takes into account all of the characteristic features of HDSs. It includes constructs for plain or algorithmic declaration of model constants, initial value problems for explicit differential-algebraic systems of equations, and initial guesses for variables. It also allows researchers to define explicit time events, modes and transitions between them upon the occurrence of events of different types, to use macros and implement event control. LISMA_HDS is defined by a generative grammar in an extended Backus-Naur form and semantic constraints. It is proved that the grammar belongs to the LL(2) subclass of context-free grammars.

scholarly journals Analysis of Related Technologies Used in Fuel Cell Vehicles

2021 ◽  
Vol 2125 (1) ◽  
pp. 012011
Author(s):  
Ziyi Du ◽  
Hongxu Zhan
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Automotive Industry ◽  
High Efficiency ◽  
Management Strategies ◽  
Production Model ◽  
Hydrogen Energy ◽  
Fuel Cell Vehicles ◽  
Energy Applications ◽  
Different Types

Abstract Nowadays, many types of fuel cells have made significant progress. In 2014, they were applied to the production model Toyota’s FCHV-Adv. With their high efficiency and low pollution, fuel cells have gradually started to replace some traditional technologies in many energy applications and production industries and have become a hot topic of interest in recent years. Depending on the type of fuel, there are various types, and different fuel cells work on different principles, leading to differences in their performance. This paper lists the different fuel cells and their application scenarios in the automotive industry. In addition, the use of hydrogen in fuel cell vehicles is also a major concern. This paper briefly discusses the current hydrogen production and four different types of fuel cell vehicles and their energy management strategies. All the technical advantages of fuel cells and hydrogen energy are ultimately reflected in fuel cell vehicles, and this paper describes the current challenges and future possibilities.

Humanness, Elevated Through its Disappearance

2011 ◽  
pp. 102-120
Author(s):  
Jeffrey M. Morris
Keyword(s):  
Virtual Worlds ◽  
Dynamic Systems ◽  
Electronic Communications ◽  
The Real ◽  
Different Types ◽  
Technological Developments

Developments in electronic communications are drastically changing what it means to be human and to interact with humans. The value of recent technological developments to artists is more than doing more, faster and better; it is also the ability to highlight and elevate humanness in new ways through art, even by appearing to replace the real with the virtual. New tools don’t simply replace humans, they allow human creators to shift into new realms of creation: creating dynamic systems and worlds instead of static products. This chapter will give consideration to the different types of presence manifest in various communications formats, stage presence in technology-mediated performance, and several artworks that bring new light to the artist’s approach to virtual worlds as a kind of counterpoint with reality.

Nuclear reactor kinetics

2021 ◽  
pp. 373-447
Author(s):  
A. John Arul ◽  
K. Obaidurrahman ◽  
Rajeev Ranjan Prasad ◽  
Om Pal Singh
Keyword(s):  
Nuclear Reactor ◽  
Reactor Kinetics ◽  
Nuclear Reactor Kinetics

scholarly journals Magnetic Micromachine Using Nickel Nanoparticles for Propelling and Releasing in Indirect Assembly of Cell-Laden Micromodules

Micromachines ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 370 ◽  
Author(s):  
Jianing Li ◽  
Huaping Wang ◽  
Juan Cui ◽  
Qing Shi ◽  
Zhiqiang Zheng ◽  
...  
Keyword(s):  
Nickel Nanoparticles ◽  
High Efficiency ◽  
Three Dimensional ◽  
Electromagnetic System ◽  
Bioactive Materials ◽  
Magnetic Assembly ◽  
Different Types ◽  
End Effectors ◽  
Set Up ◽  
High Flexibility

Magnetic micromachines as wireless end-effectors have been widely applied for drug discovery and regenerative medicine. Yet, the magnetic assembly of arbitrarily shaped cellular microstructures with high efficiency and flexibility still remains a big challenge. Here, a novel clamp-shape micromachine using magnetic nanoparticles was developed for the indirect untethered bioassembly. With a multi-layer template, the nickel nanoparticles were mixed with polydimethylsiloxane (PDMS) for mold replication of the micromachine with a high-resolution and permeability. To actuate the micromachine with a high flexibility and large scalable operation range, a multi-pole electromagnetic system was set up to generate a three-dimensional magnetic field in a large workspace. Through designing a series of flexible translations and rotations with a velocity of 15mm/s and 3 Hz, the micromachine realized the propel-and-throw strategy to overcome the inevitable adhesion during bioassembly. The hydrogel microstructures loaded with different types of cells or the bioactive materials were effectively assembled into microtissues with reconfigurable shape and composition. The results indicate that indirect magnetic manipulation can perform an efficient and versatile bioassembly of cellular micromodules, which is promising for drug trials and modular tissue engineering.

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