Pana T.,Technical University of Cluj Napoca |
Stoicuta O.,University of Petrosani
Advances in Electrical and Computer Engineering | Year: 2011
The paper presents a synthesis of an extended Gopinath observer (EGO) and analyzes the asymptotic stability of a squirrel-cage induction motor vector control system with an EGO in its loop. The considered control system is based on the direct rotor flux orientation method (DFOC) and the study of stability is based upon the linearization theorem applied around the equilibrium points of the control system, emphasizing the estimated variation domain of the rotor resistance for which the control system remains asymptotically stable.
Gut A.J.,University of Petrosani
Inzynieria Mineralna | Year: 2014
In the condition of Romanian economy and not only in this case the elaboration of market strategy within the framework of a company holds a particularly place in the elaboration of development strategy of respective company. The company development strategies which conduct to the realization of its directives constitute a responsibility of company management alongside of its performance indicators establishment. The market strategy represents a general strategy component of company development, being known that its formulation represents the central point of marketing programming. The company aiming the study target of this paper is named ECO INVEST LTD with headquarters in Deva-Romania and it has as principal activity object the wholesale and retail merchandising of constructions materials. In carrying on its activity the company used various strategies, namely: maintenance strategy, differentiated strategy, passive strategy, high demands strategy and defensive strategy. These strategies weren't in concordance with economic environment in which the company takes action the fact which imposes their modification for positioning the company on a new line in the market. The proposed strategies for the company will point the adoption of increasing strategy for obtaining an ascending trend of sales volume, a differentiated strategy so that it would concentrate on the segment of great-scale consumers, an active strategy adapted to the changes of surrounding environment and an offensive strategy by which the company will conquer a new position as part of the market.
Cioca I.-L.,Lucian Blaga University |
Moraru R.I.,University of Petrosani
Archives of Mining Sciences | Year: 2012
In order to meet statutory requirements concerning the workers health and safety, it is necessary for mine managers within Valea Jiului coal basin in Romania to address the potential for underground fires and explosions and their impact on the workforce and the mine ventilation systems. Highlighting the need for a unified and systematic approach of the specific risks, the authors are developing a general framework for fire/explosion risk assessment in gassy mines, based on the quantification of the likelihood of occurrence and gravity of the consequences of such undesired events and employing Root-Cause analysis method. It is emphasized that even a small fire should be regarded as being a major hazard from the point of view of explosion initiation, should a combustible atmosphere arise. The developed methodology, for the assessment of underground fire and explosion risks, is based on the known underground explosion hazards, fire engineering principles and fire test criteria for potentially combustible materials employed in mines.
Patrascoiu N.,University of Petrosani
International Journal of Circuits, Systems and Signal Processing | Year: 2011
This paper presents a virtual instrument built in LabVIEW used like a software solution to implement a displacement and angular speed measurement for a mobile that is moving in a circular direction. The same virtual instrument can be used also for measuring displacement and speed on the linear direction, by converting the linear movement into a circular movement or by using a linear incremental encoder. For this, first is determined the function through which is possible to detect the direction of movement and then the algorithm through which are makes the measurements and these are implemented through the graphical programming language used in LabVIEW.
Radulescu M.,University of Petrosani
Carpathian Journal of Earth and Environmental Sciences | Year: 2010
This research presents a numerical simulation of the regional scale hydrothermal fluid flow over an E-W geological profile in the Northern Lawn Hill Platform, Australia, at 1575 Ma. The modeling work assesses favorable hydrological scenarios for the formation of stratiform Zn-Pb-Ag SEDEX deposits by buoyancy driven free convection of hydrothermal fluids. Based on recent geological mapping and stratigraphic interpretation, our conceptual model depicts the stratigraphy in the area at the time of mineralization at a finer resolution than previous simulations in the area. The stratigraphic sequence consists of three cycles of clastic and carbonate basin fills, cut by several major synsedimentary faults. FEFLOW, a 3D finite element code, is used to simulate fluid flow and coupled heat transfer. Based on a two dimensional simulation, the authors aim to gain insight into the regional groundwater circulation and heat redistribution, discharge at the surface by conduits of faults, and the impact of fluid flow on the mineral precipitation in diagenetic aquifers and deposition on the sea-floor at the vents of discharging faults. The evolution of the hydrothermal system is simulated based on the key hydraulic parameters controlling the paleo fluid flow pattern and heat transport. Numerical simulations indicated the relationship between faults and aquifer sequences as being a major factor controlling buoyancy driven convection. A sensitivity analysis performed for different scenarios by varying relationships between aquifers and syn-sedimentary faults offers a better understanding of the hydrogeological constraints on the genesis of major SEDEX deposits. The purpose of the present study was to target prospective Zn-Pb deposits in the Northern Lawn Hill platform, the Mt. Isa basin by buoyancy driven fluid flow and heat transport.