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Search Results: 1 - 10 of 2620 matches for " Marcel Ilie "
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Numerical and Experimental Investigation of Aerodynamic Performance of Vertical-Axis Wind Turbine Models with Various Blade Designs  [PDF]
Mosfequr Rahman, Travis E. Salyers, Adel El-Shahat, Marcel Ilie, Mahbub Ahmed, Valentin Soloiu
Journal of Power and Energy Engineering (JPEE) , 2018, DOI: 10.4236/jpee.2018.65003
Abstract: Due to the importance and advantages of Vertical-axis wind turbines (VAWTs) over traditional horizontal-axis wind turbines (HAWTs), this paper is implemented. Savonius turbines with drag-based rotors are adopted from the two more extensive arrangements of vertical wind turbines because of their advantages. In this paper, six diverse rotor plans with measure up to cleared regions are analyzed with exploratory wind burrow testing and numerical reenactments. These proposed models incorporate a conventional Savonius with two different edges criteria and 90 degree helical bend models with two, three and four sharp edges. The models were designed using SolidWorks software then the physical models were 3D printed for testing. A subsonic open-sort wind burrow was utilized for Revolution per Minute (RPM) and torque estimation over a scope of wind speeds. ANSYS Fluent reenactments were utilized for dissecting streamlined execution by using moving reference outline and sliding lattice display methods. A 3-dimensional and transient strategy was utilized for precisely tackling torque and power coefficients. The five new rotor geometries have important advantages such as making a focal point of weight advance from the hub of revolution and causing more noteworthy torque on the turbine shaft contrasted with the customary Savonius turbine. Our new models with the names of CC model and QM model display cross-areas lessen the aggregate scope of negative torque on the edges by 20 degrees, contrasted with the customary Savonius demonstrate. Helical plans are better spread the connected torque over a total transformation resulting in positive torque over every single operational point. Moreover, helical models with 2 and 3 cutting edges have the best self-starting ability in low wind speeds. Helical VAWT with 3 edges starts revolution of 35 RPM at only 1.4 m/s wind speed under no generator stacking. The most noteworthy power coefficient is accomplished, both tentatively and numerically, by the helical VAWT with 2 sharp edges.
Aerodynamic Performance and Vibration Analyses of Small Scale Horizontal Axis Wind Turbine with Various Number of Blades  [PDF]
Mosfequr Rahman, Emile Maroha, Adel El Shahat, Valentin Soloiu, Marcel Ilie
Journal of Power and Energy Engineering (JPEE) , 2018, DOI: 10.4236/jpee.2018.66006
Abstract: The need to generate power from renewable sources to reduce demand for fossil fuels and the damage of their resulting carbon dioxide emissions is now well understood. Wind is among the most popular and fastest growing sources of alternative energy in the world. It is an inexhaustible, indigenous resource, pollution-free, and available almost any time of the day, especially in coastal regions. As a sustainable energy resource, electrical power generation from the wind is increasingly important in national and international energy policy in response to climate change. Experts predict that, with proper development, wind energy can meet up to 20% of US needs. Horizontal Axis Wind Turbines (HAWTs) are the most popular because of their higher efficiency. The aerodynamic characteristics and vibration of small scale HAWT with various numbers of blade designs have been investigated in this numerical study in order to improve its performance. SolidWorks was used for designing Computer Aided Design (CAD) models, and ANSYS software was used to study the dynamic flow around the turbine. Two, three, and five bladed HAWTs of 87 cm rotor diameter were designed. A HAWT tower of 100 cm long and 6 cm diameter was considered during this study while a shaft of 10.02 cm diameter was chosen. A good choice of airfoils and angle of attack is a key in the designing of a blade of rough surface and maintaining the maximum lift to drag ratio. The S818, S825 and S826 airfoils were used from the root to the tip and 4° critical angle of attack was considered. In this paper, a more appropriate numerical models and an improved method have been adopted in comparable with other models and methods in the literature. The wind flow around the whole wind turbine and static behavior of the HAWT rotor was solved using Moving Reference Frame (MRF) solver. The HAWT rotor results were used to initialize the Sliding Mesh Models (SMM) solver and study the dynamic behavior of HAWT rotor. The pressure and velocity contours on different blades surfaces were analyzed and presented in this work. The pressure and velocity contours around the entire turbine models were also analyzed. The power coefficient was calculated using the Tip Speed Ratio (TSR) and the moment coefficient and the results were compared to the theoretical and other research. The results show that the increase of number of blades from two to three increases the efficiency; however, the power coefficient remains relatively the same or sometimes decreases for five bladed turbine models. HAWT rotors and shaft vibrations were analyzed for
LIFE CYCLE MANAGEMENT FOR AN INVESTMENT PROJECT IN CLUJ-S LAJ AREA, ROMANIA
Vasile Iuliu CIOMO?,Dorin Marcel CIATAR??,Ilie VLAICU
Transylvanian Review of Administrative Sciences , 2011,
Abstract: The Project Life Cycle refers to a logical sequence of activities to accomplish the project’s goals or objectives. Regardless of scope or complexity, any project goes through a series of stages during its life. Authors’ experience in preparing and implementing investment projects in the water sector has led to several conclusions: there is first an identification phase, in which the outputs and critical success factors are defined, followed by a planning phase, characterized by breaking down the project into smaller tasks, an execution phase, in which the project plan is executed, and lastly a completion phase, that marks the closure and exit of the project. Investment project activities must be grouped into phases because by doing so, the project management and the core team can efficiently plan and organize resources for each activity, and also objectively measure achievement of the goals.This paper introduces several issues related to the Project Cycle Management for a large local infrastructure investment project in the Cluj- S laj area, Romania. Successfully managing the project cycle and making timely decisions at every stage (identification, planning, execution and sustainability) require the Project Management Unit from the Cluj-S laj Water Company to constantly understand and adapt to strategic considerations, both external and internal.
Simplifying Stochastic Mathematical Models of Biochemical Systems  [PDF]
Silvana Ilie, Samaneh Gholami
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.41A038
Abstract:

Stochastic modeling of biochemical reactions taking place at the cellular level has become the subject of intense research in recent years. Molecular interactions in a single cell exhibit random fluctuations. These fluctuations may be significant when small populations of some reacting species are present and then a stochastic description of the cellular dynamics is required. Often, the biochemically reacting systems encountered in applications consist of many species interacting through many reaction channels. Also, the dynamics of such systems is typically non-linear and presents multiple time-scales. Consequently, the stochastic mathematical models of biochemical systems can be quite complex and their analysis challenging. In this paper, we present a method to reduce a stochastic continuous model of well-stirred biochemical systems, the Chemical Langevin Equation, while preserving the overall behavior of the system. Several tests of our method on models of practical interest gave excellent results.

Automatic Simulation of the Chemical Langevin Equation  [PDF]
Silvana Ilie, Monjur Morshed
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.41A036
Abstract:

Biochemical systems have important practical applications, in particular to understanding critical intra-cellular processes. Often biochemical kinetic models represent cellular processes as systems of chemical reactions, traditionally modeled by the deterministic reaction rate equations. In the cellular environment, many biological processes are inherently stochastic. The stochastic fluctuations due to the presence of some low molecular populations may have a great impact on the biochemical system behavior. Then, stochastic models are required for an accurate description of the system dynamics. An important stochastic model of biochemical kinetics is the Chemical Langevin Equation. In this work, we provide a numerical method for approximating the solution of the Chemical Langevin Equation, namely the derivative-free Milstein scheme. The method is compared with the widely used strategy for this class of problems, the Milstein method. As opposed to the Milstein scheme, the proposed strategy has the advantage that it does not require the calculation of exact derivatives, while having the same strong order of accuracy as the Milstein scheme. Therefore it may be used for an automatic simulation of the numerical solution of the Chemical Langevin Equation. The tests on several models of practical interest show that our method performs very well.

Efficient computation of spaced seeds
Silvana Ilie
BMC Research Notes , 2012, DOI: 10.1186/1756-0500-5-123
Abstract: SpEED uses a hill climbing method based on the overlap complexity heuristic. We propose a new algorithm for this heuristic that improves its speed by over one order of magnitude. We use the new implementation to compute improved seeds for several software programs. We compute as well multiple seeds of the same weight as MegaBLAST, that greatly improve its sensitivity.Multiple spaced seeds are being successfully used in bioinformatics software programs. Enabling researchers to compute very fast high quality seeds will help expanding the range of their applications.The most frequently used tools in bioinformatics are those searching for similarities, or local alignments, between biological sequences. This problem can be solved exactly using the dynamic programming algorithm of Smith-Waterman in quadratic time. Many instances, including all database searches, are too large for this approach to be feasible and heuristic algorithms are used instead [1,2]. The most widely used program in bioinformatics, BLAST [2,3], is one such tool. It uses the so-called "hit and extend" approach: a hit consists of 11 consecutive matches between two sequences and represents a potential local alignment. The hit is then extended both ways in search for similarity.It is clear that not all local alignments have to include an identical stretch of length 11. It has been already noticed in [4] and then again in [5] that requiring that the matches are not consecutive increases the chances of finding alignments. The idea of optimizing the way the required matches are placed has been investigated in [6,7], the latter having used it in a similarity search software, PatternHunter. Much work has been dedicated to spaced seeds. For a survey of earlier work, we refer the reader to [8].The 11 consecutive matches of BLAST are called a contiguous seed, denoted 11111111111 (for 11 consecutive matches), whereas the one of PatternHunter is a spaced seed, 111*1**1*1**11*111; a 1 represents a match and * a don
The inheritance rights of the surviving spouse provided by the romanian law
Urs,Ilie;
Revista de derecho (Valparaíso) , 2009, DOI: 10.4067/S0718-68512009000100005
Abstract: in the old romanian law succession, the transmission was governed by legislation that was under the influence of roman law. the surviving spouse was quite at a disadvantage compared to the blood relatives of the defunct. the unfair succession situation of the surviving spouse was the object of vehement criticism in the romanian doctrine. nowadays, the inheritance rights of the surviving spouse are regulated by law nr. 319 of 10th june 1944 for the inheritance right of the surviving spouse that implicitly abrogated the dispositions of article 679, 681-684 of the romanian civil code. thus, according to law nr. 319 of 10th june 1944, the surviving spouse has three distinctive succession rights: i) a general inheritance right, in competition with any of the classes of heirs i-iv; ii) a special inheritance right over the movable goods and objects belonging to the household and over the wedding gifts; iii) a temporary right of occupancy of the house.
The Sale with Repurchase Clause
Urs,Ilie;
Revista de derecho (Valparaíso) , 2010, DOI: 10.4067/S0718-68512010000200002
Abstract: the sale with repurchase clause was regulated in 1864 by the civil code, within the meaning of articles 1371-1387, as a variety of sale affected by a cancellation condition. the sale with repurchase clause was frequently used in practice in order to breach the public provisions of article 1689 of the romanian civil code, on mortgage matters. taking into consideration that the sale with repurchase clause was actually a way to breach the provisions of article 1689 of the romanian civil code, giving birth to a lot of abuses on the part of the creditors, the romanian legislator decided to prohibit this type of sale. we also consider that, de lege ferenda, the implementation of a new prohibition law of the sale with repurchase clause is both necessary and useful.
NATO CONCEPT EVOLUTION – CONSEQUENCE OF THE CHANGES OCCURRED IN THE INTERNATIONAL SECURITY ENVIRONMENT
Marin ILIE
Journal of Defense Resources Management , 2010,
Abstract: We initiated our endeavor staring from an undisputed reality, that is, NATO changes its strategies and, implicitly, concepts, according to the developments occurred in the international security environment, in order to be able to respond to any challenge operatively and adequately. We would like to emphasize that regardless of the concepts formulation and application, the Organization’s fundamental values, and particularly its purely defensive character and the principle of collective defense do not alter.
THE NEW STRATEGIC CONCEPT NATO 2010
Marin ILIE
Journal of Defense Resources Management , 2011,
Abstract: NATO (The North Atlantic Treaty Organization) – OTAN (Organisation du Traité de l’Atlantique Nord) has been, since its estabslishment, oustandingly receptive to the international security environment developments and has always altered its strategy and strategic concepts in order to meet the afferent challenges, with an emphasis on its purely defensive character. The most favorable moment of this kind have been its summits: Rome (1991), Washington (1999) and Lisbon (2010), on which our paper will focus. The greats mutations in the last decade have called for the creation of the new strategic concept NATO 2010, developed in the Lisbon summit declaration of 19-20 November 2010.
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