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Recent 35

Vol. 13 (2012), No. 2 (35), July 2012

 

This issue of the RECENT® journal was edited and multiplied with support of:

  • Transilvania University of Brasov, Romania

  • Romanian Association for Nonconventional Technologies


CONTENTS


  • Christian ASTALOSCH, Cătălin George ATANASIU

Mechanical Properties Determination of TPE Covering for Automotive Door Sealing's

» Abstract

A modern trend in the industry producing car door sealing system consists of more widespread use of TPE (thermoplastic elastomer). The reason lays in the elastic properties similar performance elastomers, extrusion processing is simple and similar to plastics. In addition, the TPE substrates allow through coextrusion coating of surfaces subject to friction with a sliding TPE material. Co-extruded coatings mentioned above, must be validated in terms of quality. The control mode, used by the authors is based on: visual inspection, dimensional control of coating thickness applied and control sliding abrasion resistance. Endurance test of automobile component sealing shows that the method applied by the authors is relevant and sufficient to ensure quality PET material coatings sliding. In addition, TPE sliding material Lubmer TM80 meets the conditions imposed by the car and can be recommended as a good solution price/performance.

» Keywords

TPE, substrate, mechanical, abrasion, geometrical, thickness

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  • Ion BALCU, Ioan ROŞCA, Cosmin Constantin BORICEAN

Dynamical Behaviour of Pressure Limiting Valves

» Abstract

In this paperwork, there are highlighted aspects regarding mathematical modeling of pressure limiting valves, used on hydraulic systems, and aspects related to stability analysis methods based on Ince-Strutt diagram.

» Keywords

valve, Ince-Strutt, dynamic behaviour

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  • Iulian BĂDAN, Gheorghe OANCEA, Mircea DRĂGOI

Software Tool Used for Holes Manufacturing Processes

» Abstract

The paper presents a software tool, developed in AutoCAD environment, used for manufacturing processes of holes. The holes are placed on solids with different configurations. The software tool is part of CAD/CAM system software, which is connected with a software module dedicated to holes modelling. The first one generates the technological information necessary for the holes fabrication process. The output of the software tool, after managing information about CNC machines, tools, cutting data, is the NC file. The CAD/CAM system covers most of the production cycle of industrial products with holes, from concept to manufacture, using the technological intelligent object concept.

» Keywords

CAD/CAM, intelligent object, holes manufacturing, AutoCAD

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  • Tibor BEDŐ, Vasile JIMAN, Aurel CRIŞAN, Ioan CIOBANU

Research by Computer Simulation Regarding the Influence of Coolers on Feeders Performance

» Abstract

The paper presents the results obtained by computer-aided simulation related to the solidification of castings, concerning the influence of coolers on feeder performance. The results reveal that feeder volume can be considerably reduced by utilization of coolers combined with feeders.

» Keywords

cast parts, coolers, feeders, simulation of solidification

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  • Cosmin Constantin BORICEAN, Ion BALCU, Ioan ROŞCA

Analytical Modeling of Turbocharger Rotors

» Abstract

Rotordynamics was and still is a high applicability field to all categories of rotating machines. The turbocharger is part of high precision rotating machines. Its rotor, sustained by two categories of bearings, represents the main part of the turbocharger: classical ones use hydrodynamic bearings; modern ones use hybrid rolling bearings with ceramic rolling elements. The performances that turbochargers are capable of are closely related to dynamical phenomena that appear at the level of its rotor. Even if we talk about vibration behaviour, or unbalanced masses and assembly defects, the turbocharger rotor has a high precision execution, and by monitoring its behaviour, we are capable to obtain important data sets, which could predict its durability and also charging performances. The paper work is focused on highlighting some aspects related to mathematical modeling of turbocharger rotors and also in highlighting some aspects related to rotor dynamic stability, influenced by parameters related to: mass; eccentricity, rigidity and damping effects.

» Keywords

turbocharger, rotordynamics, bearings, rigidity, damping

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  • Gavrilă CALEFARIU, Cătălin GHEORGHE, Magdalena BARBU, Flavius SÂRBU

Business Engineering and Management, Occupation, Vocation, and Academic Specialization

» Abstract

New products appear because of the existence of a new application on the market or as a result of the progress. There are situations when complete new products generate demand on the market. The subject of this article is a new product to enrich the nomenclature of academic professional interests. The article presents the premises which have led to the new professional interest named “Business Engineering and Management” and the arguments determining the development of this new professional interest in the academic and economic environment in Romania.

» Keywords

entrepreneurship, professional interest, engineering, management

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  • Romeo CIOARĂ

Romanian Inventics in 2001-2010 Years. Patent Applications

» Abstract

Invention is the most important, the most widely known and the most largely recognized element of intellectual property. Patenting essentially supposes the explicit manifestation by a natural person or legal entity, of the interest in protecting, within a certain geographical area, of an intellectual property, to the purpose of obtaining certain advantages. The State Office for Inventions and Trademarks (OSIM) is a specialized organ of the central public administration, subordinated to the Government, with unique authority throughout Romania, in the field of industrial property protection. In Romania, the abstracts of the patent applications and of the awarded patents are published in the Official Bulletin of Industrial Property (BOPI), which is monthly issued. The paper herein submits synthetic data, examples and an analysis with respect to the patent applications registered in Romania and published in BOPI, during the period 2001-2010.

» Keywords

inventics, patent application, applicant, analysis

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  • Elena EFTIMIE

Solar Radiation Estimation under Clear Sky Conditions for Brasov Area (Romania) - Linke Turbidity Factor

» Abstract

The determination of solar radiation is important for solar renewable systems design. The solar radiation is dependent on several factors such as, latitude and altitude location, season, day, time, content of dust, water vapour and aerosols in the atmosphere. In addition, mounting of solar energy systems in urban areas requires the determination of solar radiation, because in urban areas there is a more significant attenuation of solar radiation due to atmospheric pollution. However, the development of some methods to estimate the solar radiation assumes the knowledge of some climatological parameters (the optical air mass, Rayleigh optical depth, Linke turbidity factor, etc.). Among all these parameters, one of the most important is represented by the atmospheric turbidity, due to the relationship existing between aerosols and attenuation of solar radiation reaching the Earth’s surface. In this context, this paper proposes a study of the Linke turbidity factor, for Brasov urban area, with the purpose of more accurate solar radiation estimation. In addition, this study recommends the use of some correction coefficients for the direct and diffuse radiations; these coefficients are empirically determined and they depend on the specific geographical and climatic conditions of the considered site.

» Keywords

clear sky conditions, direct radiation, Linke turbidity

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  • Florina-Cristina FILIP

Theoretical Description of Review Contract Documents

» Abstract

The aim of this paper is to describe the process of review contract documents to ensure that their contents are properly checked and are signed when they are free of ambiguities and unreasonable risks. During the review, all requirements (contract content and applicable documents) must be taken into account and the relevant technical departments called in to carry out assessments where appropriate. Accepted requirements must be introduced to the company’s organization. The specialist scope applies to all customer requirements, contract documents and standards, which are not processed and released as part of a project.

» Keywords

review, contract document, customer

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  • Aurel FRATU, Mariana FRATU

Tracking Control of Robotic Multi-Body Systems

» Abstract

This paper presents a simple methodology for obtaining the entire set of continuous controllers that cause a nonlinear dynamical system to exactly track a given trajectory. The trajectory is provided as a set of algebraic differential equations that may or may not be explicitly dependent on time. The method provided is inspired by results from analytical dynamics and the close connection between nonlinear control and analytical dynamics is explored. The results provided in this paper here yield new and explicit methods for the control of highly nonlinear systems. The paper is based on previous work of the authors.

» Keywords

nonlinear control, nonlinear dynamical system, multi-body systems

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  • Mariana FRATU, Aurel FRATU

Space Management in Smart Room

» Abstract

Seeking to be sensitive to users, smart home researchers have focused on the concept of control. They attempt to allow occupants to gain control over their lives. Homeowners and occupants want more control of their lives. The study of Intelligent Home is now a common topic worldwide. In current quest for modernization, designers need that the building owner receives the best product possible. Everyday, building designers face exciting new challenges in incorporating new and innovative technologies in designing an efficient integrated intelligent building in areas of the building structure and its mechanical and electrical systems. The innovative technologies would need to ensure that the end users achieve the utilization of its abilities in optimization of there home space. This paper is focused on the various functions available in Room Automation System (BAS) and the benefits in having such functions.

» Keywords

smart room, smart house, intelligent building

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  • Liviu JELENSCHI, Corneliu COFARU, Gabriel SANDU

Investigating the Effects of Oil Pressure on Valve Rotation for a Direct Acting Valve Train

» Abstract

This paper investigates the influence of oil pressure on the engine exhaust valve rotation for a direct acting valve train. In introduction, a short presentation of the direct acting valve train is made and the necessity of the valve rotation is described. The test rig and the equipment used for measuring the influence of the oil pressure upon valve rotation are described in the main section of the paper. The results obtained revealed the fact that the oil pressure represents an important parameter, which influences the valve rotation.

» Keywords

internal combustion engines, valve train, valve rotation, oil pressure

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  • Vasile JIMAN, Ioan CIOBANU, Aurel CRIŞAN, Tibor BEDŐ

Experimental Research on the Influence of Coolers on Feeder Performances

» Abstract

The paper presents the results obtained by experimental research concerning the influence of coolers on feeder operation. The experimental results confirm the results of the simulation of solidification study. In the analyzed case, the placing of a cooler at the base of the casting hot spot has caused a 51.84% increase of the liquid alloy utilization index, namely from 21.99% to 33.39%.

» Keywords

cast part, feeder, cooler

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  • Konstantin KAMBEROV, Georgi TODOROV, Borislav ROMANOV, Tsvetozar IVANOV

Simulation Driven Improvement of Worm Gearset Performance Using Virtual Prototype

» Abstract

This study aims to present a contemporary approach for improvement of gearset output performance, based on virtual prototype. Powerful advantage of accessing gears parameters in detail at early stage of product development allows saving expenses and time to bring new product to the market by reducing the time for excessive physical prototyping and testing. Moreover, it is possible to quantify important parameters, that could not be measured directly by tests, and thus, to reach optimal design in cases of extreme loading. Specific focus in this paper is set on a worm gearset, used for safety device in lifting equipment for nuclear power plants. The gear pair works as safety brake, using frictional parameters, typical for worm gearsets. The study is initiated after observed failures on physical prototype and the necessity of design improvement to meet requested performance. Some of the requirements are controversial and a balanced solution of the design parameters set is needed. Virtual prototype is used to be explored using numerical techniques, especially Finite Element Method. Nonlinear model of contact behaviour is used to increase the accuracy of modeled physics task. An initial design is explored and analysed, which is used as a basis for subsequent improved design development. Both initial and optimal design are compared and analysed. Complete research illustrates a successive implementation of an approach, based on virtual prototyping, for specific gear design development. The main result is measured in saved time for physical prototyping and reaching an optimal solution.

» Keywords

wormset, nonlinear, contact, FEA, virtual prototype

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  • Bogdan - Sorin NEAGOE, Ionel MARTINESCU

Web-Based Methodology for the Management of FMEA Projects

» Abstract

The Failure Mode and Effects Analysis (FMEA) is a technique for the management of the reliability and security of systems, products and processes that helps to identify the most important problems that can lead to their failure and find the necessary solutions for the reduction of the associated risks. The purpose of this paper is to present a new methodology that uses the internet for the development and management of FMEA projects. Based on this methodology was developed a Software application that will be presented in the future in another paper.

» Keywords

FMEA, project management, internet, cloud storage, knowledge base

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  • Vasile PRISACARIU, Mircea BOŞCOIANU, Ionică CÎRCIU

Management of Robotic Aerial Systems (RAS) Accomplishment

» Abstract

Robotic aerial systems have developed rapidly due to data demands from areas of interest and due to technology’s miniaturization. Although these aerial systems have high capabilities, they are used for specific tasks and limited to atmospheric stability disturbances. The paper aims to present an overview regarding the decision-making in accomplishing a robotic aerial system in the context of existing parts in the field of product management, by stages of design, manufacturing, equipment and ground and flight-testing. Performances and technical and tactical characteristics of an air vector depend directly on both the systems’ reliability and on the influence of disturbance factors.

» Keywords

robotic aerial systems, aeronautical management, aerodynamic performances

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