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Search Results: 1 - 10 of 83 matches for " Iztok Hace "
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The Pressure Relief System Design for Industrial Reactors
Iztok Hace
Journal of Industrial Engineering , 2013, DOI: 10.1155/2013/453509
Abstract: A quick and simple approach for reactor—emergency relief system design—for runaway chemical reactions is presented. A cookbook for system sizing with all main characteristic dimensions and parameters is shown on one realistic example from process industry. System design was done based on existing theories, standards, and correlations obtained from the literature, which were implemented for presented case. A simple and effective method for emergency relief system is shown, which may serve as an example for similar systems design. Obtained results may contribute to better understanding of blow down system frequently used in industrial plants, for increasing safety, decreasing explosion damage, and alleviating the ecological problems together with environmental pollution in case of industrial accidents. 1. Introduction In process industry, raw materials are converted into various commercial products using different techniques. One frequently used method is their conversion by exothermic chemical reactions which can lead to a reactor thermal runaway if the heat generation rate exceeds the heat removal rate during process [1]. Pressure build-up during the runaway is caused by an increasing vapor pressure of liquid components and by the production of noncondensable gases. Apart from the loss of reactor inventory due to an uncontrolled conversion process, a runaway reaction may lead to severely damaged equipment or even a physical explosion if pressure build-up inside the reactor exceeds the design pressure. The emergency relief system is composed of vent area, vent rupture membrane, safety relief valve, vent pipes, blow down tank, horizontal condenser, scrubber with absorber and vertical condenser, outflow chimney, corresponding pumps, fan, pipes, fitting, and supply system with electricity, cooling water, and neutralization medium. In case of reaction runaway, the vent rupture disc opens and the reactor mixture blows out into the vent pipes and flows into blow down tank. Due to short residence time of reactor mixture in the blow down tank, the volume changes and the pressure decreases at isothermal conditions, which results in the condensation of reaction mixtures. Remained two phases flow instantaneously blows into horizontal condenser, where it cools down, condensates, and flows into absorber with vertical condenser, where it is neutralized [2–4]. In present study, a detailed design of emergency relief system is shown based on Design Method for Emergency Relief Systems (DIERSs). It incorporates the state-of-the-art knowledge obtained from mechanical,
Bilateral Teleoperation by Sliding Mode Control Design Approach
Ales Hace
International Journal of Online Engineering (iJOE) , 2008, DOI: 10.3991/ijoe.v4i4.700
Abstract: Sliding mode control has been used extensively in robotics to cope with parameters uncertainty, model perturbations and system disturbance. Bilateral robotic teleoperators are often required to provide a haptic interaction in telerobotic applications in which human kinesthetic sense is stimulated locally by remote environment. The paper deals with bilateral control for a force-reflection master-slave telerobotic architecture. It involves a short overview of basic bilateral modes. Chattering-free SMC design procedure for force-reflecting master-slave teleoperator is presented. The proposed bilateral control scheme was experimentally validated for a 1DOF master-slave teleoperator.
Guest Editorial
Riko ?afari?,Ale? Hace
International Journal of Online Engineering (iJOE) , 2008, DOI: 10.3991/ijoe.v4i4.711
Soft roll linings - better conduits: First press of the PS 2, paper machine, Beli e, Croatia
Dolenc Iztok
Hemijska Industrija , 2005, DOI: 10.2298/hemind0508185d
Abstract: Paper with demanding technical properties is formed in the press of the paper machine when the paper pulp is passed between the rolls. In order to form paper in the appropriate manner, an elastic lining with particular stiffness is spread over the rolls. In this study a practical example of how softer linings generally give better results concerning the percentage of the dry part and the paper structure is presented. From the rubber roll manufacturers' point of view, the weak side of soft linings lies in greater deformations, which present difficulties in obtaining good adhesion between the lining and metal core of the roll. Only the best manufacturers in the industry can match such high demands.
Bose Hubbard model far from equilibrium
Iztok Pizorn
Physics , 2013, DOI: 10.1103/PhysRevA.88.043635
Abstract: We study the nonequilibrium steady state of the Bose Hubbard model coupled to Lindblad reservoirs, using the density matrix renormalization group in operator space. We observe a transition from a flat particle density profile in the noninteracting limit to the linear profile with onset of the interparticle interaction. Analyzing the effect of coherent pumping on the nonequilibrium steady state we find a subspace which remains unaffected by the pumping in the noninteracting limit with the protection gradually diminishing due to interparticle interaction. In the equilibrium situation with one or more symmetric reservoirs we show analytically that the steady state of the system is a product state for any interaction strength. We also provide analytical results in the noninteracting limits, using the method of the third quantization in operator space.
Integrations on rings
Iztok Banic
Mathematics , 2014,
Abstract: In calculus, an indefinite integral of a function $f$ is a differentiable function $F$ whose derivative is equal to $f$. In present paper, we generalize this notion of the indefinite integral from the ring of real functions to any ring. The main goal of the paper is to focus on the properties of such generalized integrals that are inherited from the well-known basic properties of indefinite integrals of real functions.
Concept of drafting detection system in Ironmans
Iztok Fister,Iztok Fister Jr
Computer Science , 2012,
Abstract: One of the biggest challenges for the Computer Science of today can be summed up by the paradigm "access to information from $everywhere$ at $anytime$". This is especially true for pervasive computing. With the growth of mobile devices (e.g., smart-phones), on the one hand, and the quick development of the Internet (this has become the really pervasive network of today), on the other hand, the development of real-time pervasive applications has broadened. This paper focuses on the problem of drafting detection in the Ironman triathlons which causes serious problems for the majority of organizers regarding such competitions. A concept of drafting detection system in Ironman is based on the paradigm of pervasive computing. Results of performing a test system show that this concept can along with further development of computer technologies become a reality in the near future.
Using the quaternion's representation of individuals in swarm intelligence and evolutionary computation
Iztok Fister,Iztok Fister Jr
Computer Science , 2013,
Abstract: This paper introduces a novel idea for representation of individuals using quaternions in swarm intelligence and evolutionary algorithms. Quaternions are a number system, which extends complex numbers. They are successfully applied to problems of theoretical physics and to those areas needing fast rotation calculations. We propose the application of quaternions in optimization, more precisely, we have been using quaternions for representation of individuals in Bat algorithm. The preliminary results of our experiments when optimizing a test-suite consisting of ten standard functions showed that this new algorithm significantly improved the results of the original Bat algorithm. Moreover, the obtained results are comparable with other swarm intelligence and evolutionary algorithms, like the artificial bees colony, and differential evolution. We believe that this representation could also be successfully applied to other swarm intelligence and evolutionary algorithms.
Measuring Time in Sporting Competitions with the Domain-Specific Language EasyTime
Iztok Fister Jr.,Iztok Fister
Computer Science , 2012,
Abstract: Measuring time in mass sporting competitions is unthinkable manually today because of their long duration and unreliability. Besides, automatic timing devices based on the RFID technology have become cheaper. However, these devices cannot operate stand-alone. To work efficiently, they need a computer timing system for monitoring results. Such system should be capable of processing the incoming events, encoding and assigning results to a individual competitor, sorting results according to the achieved time and printing them. In this paper, a domain-specific language named EasyTime will be defined. It enables controlling an agent by writing events to a database. Using the agent, the number of measuring devices can be reduced. Also, EasyTime is of a universal type that can be applied to many different sporting competitions
A Hybrid Artificial Bee Colony Algorithm for Graph 3-Coloring
Iztok Fister Jr.,Iztok Fister,Janez Brest
Computer Science , 2012, DOI: 10.1007/978-3-642-29353-5_8
Abstract: The Artificial Bee Colony (ABC) is the name of an optimization algorithm that was inspired by the intelligent behavior of a honey bee swarm. It is widely recognized as a quick, reliable, and efficient methods for solving optimization problems. This paper proposes a hybrid ABC (HABC) algorithm for graph 3-coloring, which is a well-known discrete optimization problem. The results of HABC are compared with results of the well-known graph coloring algorithms of today, i.e. the Tabucol and Hybrid Evolutionary algorithm (HEA) and results of the traditional evolutionary algorithm with SAW method (EA-SAW). Extensive experimentations has shown that the HABC matched the competitive results of the best graph coloring algorithms, and did better than the traditional heuristics EA-SAW when solving equi-partite, flat, and random generated medium-sized graphs.
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