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Recent 46

Vol. 16 (2015), No. 3 (46), November 2015

 

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


CONTENTS



  • Nicolae BOIAN

Diagnose of Strategy to Small and Middle Size Enterprises (SME)

» Abstract

This paper presents an original method of analysis of strategy to SME. Based on the specific features of SME strategic plans among which are the subjective determination by a small number of entrepreneurs and the limited resources available, on sets the bases for a scientific and objective assessment of a company's strategic position. Following evaluation the main coordinated of strategic optimization plan sets out, which ensures the minimal deviations from optimum. In presenting the method are established the stages of the evaluation process consisting in determining the strategic activity domain (SAD), assessment attractions and competitive forces using multi-criteria techniques, and evaluation of strategic position in the context of matrix type Boston Consulting Group and Mc Kinsey. Finally, an example of diagnose of strategy to enterprise in the field of industrial production is presented and draw conclusions of applying method.

» Keywords

diagnose, strategy, attractions, competitive forces

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  • Traian Alexandru BUDA, Magdalena BARBU, Gavrilă CALEFARIU

Optimizing the Work Centers Loading Level

» Abstract

This paper present a new approach for optimizing the loading level of the work centers in a manufacturing system or supply chain. The loading level problem is solved when the following information is available: how many parts can be produced at each resource and from each material, considering the given time span, the routing file with more alternatives and the product mix based on the customer orders. In this paper, optimization is based on the adoption of matrix calculus combined with linear programming simplex algorithm. The opportunity of such a model is that the classic MRP data structure is directly manipulated with the purpose of obtaining the loading level and the production capacity. The results are used in the rough-cut capacity planning, budgeting process, and customer order confirmation. In addition, the facile integration in MRP systems is a vital point. The model was created also to serve a large variety of manufacturing systems.

» Keywords

loading level, alternative routings, MRP systems, capacity planning, Simplex

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  • Horațiu BULEA

Research of Orthopaedic Ceramic Prostheses Personalized

» Abstract

The pre-sintering method can offer a suitable solution for manufacturing of orthopaedic prostheses that are usually difficult to do. This paper presents the results of some experiments on manufacturing of orthopaedic prostheses by aluminium oxide ceramic material, the mechanics of the sintering process and the control of dimension and forms of the component parts of the personalized orthopaedic prostheses. After measuring the parts, there were analysed the main dimensional parameters of precision to reveal the proper solution for obtaining the required quality of the process.

» Keywords

ceramic, personalized, linear contraction coefficient, orthopaedic prostheses

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  • Emilia CALEFARIU, Traian BUDA, Nicolae BOIAN

Modeling the Decision of Making a Virtual Enterprises

» Abstract

This paper proposes a new method of analysis for the index return on the capital involved in the development of an investment project. The method is useful in terms of financing and association of multiple choices, identifying the most advantageous alternative for the company and to determine more accurately the path that must be followed. It is considered the possibility of accessing a Virtual Enterprise and the possibility of an external financing sources; the paper's purpose is to identify the best option for financing the company between the two.

» Keywords

virtual enterprise, return on capital, financing required, association

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  • Ioan CIOBANU, Sorin Ion MUNTEANU, Tibor BEDÖ, Florin MUSTEAȚĂ

On Top Riser Working

» Abstract

In the case of castings that have a hotspot at the, top riser are normally used in industrial practice. It is envisaged that the hotspot is very close to the riser. It is considered that the liquid alloy flows more easily from riser in the casting. The paper shows that this view is wrong. Is analyzed by computer simulation, the part solidification with top riser and with lateral riser. The results show that for the same riser size, the top riser assure not shrinkage elimination inside the casting, while in the case of lateral is obtained the casting without shrinkage.

» Keywords

riser, feeder, casting, solidification simulation

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  • Marcel DĂIAN, Ioan CIOBANU, Aurel CRIŞAN

On The Opportunity to Manufacturing of Metallic Balls with Cavity by Centrifugal Casting

» Abstract

A centrifugal casting procedure and installation with three axes of rotation were patented at Transilvania University of Brasov. This can be deployed for casting hollow metal balls. The advanced multiple-criteria analysis is conducted in order to evaluate the opportunity of using this casting procedure and installation for the manufacturing of mill balls. Seven procedures for mills balls manufacturing had been are comparing. The analysis shows so as to produce that balls by centrifugally casting has the highest performance coefficient.

» Keywords

multiple-criteria analysis, centrifugal casting, metal balls, ball mills

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  • Adrian DĂNILĂ, Radu CÂMPEANU

The Implementation of the Frequency Analyzer Principle for the Estimation of the Electronically Switched Capacitor's Capacitance

» Abstract

In this work, the authors investigated the implementation of the frequency analyzer principle to produce real-time estimates of the equivalent capacitance of the electronically switched capacitor for the two-phase induction servo-motor. The on-line estimation of the capacitance of the start-up switched capacitor for the auxiliary phase of the two phased induction motor is subjected to disturbances due to the large commutation voltages. The correlation frequency analyzer is mainly used in systems identification to estimate the dynamic models within the frequency and correlation identification methods. In comparison with the direct data averaging, the frequency analyzer implementation is less noise sensitive, more accurate and subjected to the embedded implementations. The experimental results of this investigation proved that the embedded implementation of the frequency analyzer principle is possible within the same microcontroller that produces the control law for the switched capacitor.

» Keywords

electronically switched capacitor, frequency analyzer, two-phase induction servo-motor

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  • Konstantin D. DIMITROV, Borislav B. GRIGOROV

Experimental Platform for Simulation and Analysis of Systems States and Fault Diagnosis in Industrial and Logistics Systems

» Abstract

The present paper describes the development of advanced experimental platform, designated for modelling, simulation and analysis of technologic operations, systems states, and fault diagnosis realized in real and/or simulated industrial and logistics facilities. The developed experimental platform can be applied in research and development studies as well as in teaching activities performed by PhD-students, PostDoc-students and other academic staff in Technical University of Sofia, Bulgaria.

» Keywords

experimental platform, simulation and analysis of systems states, fault diagnosis, reliability enhancement

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  • Valentin DIŢU

The Influence of the Ratio Cutting Depth/Nose Radius of TNMG160408-P30 Plate on the Cutting Thermocurrent at Cutting OLC45 Steel

» Abstract

At metals cutting with metallic edges it appears an electrical current due mainly to the temperature in the cutting zone. Because the temperature in the cutting zone shows how the cutting process develops and the resulted electrical current estimates precisely the temperature, results that the electrical current at cutting is a simple diagnose method due to the possibility to be measured with accuracy. The paper shows the influence of the ratio between the cutting depth and nose radius of TNMG160408-P30 metallic carbide plate at turning OLC45 steel. It was chosen the influence of the ratio between cutting depth and nose radius of the plate because the phenomenon during the cutting process are developing differently in the nose radius zone than in the rectilinear part of the edge. The paper shows this aspect.

» Keywords

cutting, turning, electrical current (thermocurrent), diagnose

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  • Adriana FLORESCU, Sorin BARABAŞ, Magdalena BARBU, Traian BUDA

Development and Implementation of a Monitoring and Real-Time Management System in Flexible Manufacturing

» Abstract

The paper presents the development and implementation of applications - software package for monitoring and real-time management of a flexible manufacturing line of cylindrical parts, serviced by an industrial logistic subsystem with feeding - transport - transfer and storage functions. The user can then monitor and control the entire system from the control monitor, shortcomings is noted in real time on each module of the process. The applicative character of the research is to simulate the operation in a real physical system, designed and based on mathematical models of sizing and configuration, previously developed and the validation of simulation. The simulation revealed the behavioural properties of the flexible line and the evolution in real process. The developed applications -simulation programs, arose from the need to analyze and study the behaviour of a real system, in order to control and management in the future the system and will open new lines of research, with the cumulative effect of reducing the uncertainty that exists in flexible manufacturing.

» Keywords

production systems, flexibility, modelling, simulation, management

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  • Cătălin GHEORGHE

Limits of Salary Cost Analysis in Industrial Companies

» Abstract

An investigation of this economic phenomenon supposes the existence of proper procedures, principles, methods and tools that are generally specific to science but also to the economic field. A scientific method assures, by procedures and tools, the detachment from the economic reality and the entrance in the scientific theory of regularities, principles and laws determining and governing the economic phenomena. To such respect, this article focuses within the general topical economic analysis of the industrial companies on a specific identification of analysis models used in this section of an analysis models management. Such investigation is required in order to have a right tool to avoid errors that are so frequent in industrial business regarding the salary costs cut down that happens so often to lead to a diminution in the employees’ salaries or their lay off especially within economic crisis periods.

» Keywords

analysis model, salary cost, industrial companies

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  • Cosmin-Constantin IACOB, Gabriel BORSOS, Gavrilă CALEFARIU

Management Methods and Techniques Applicable in Defence Industry

» Abstract

After 1990 the Romanian society has undergone the transition from socialism to capitalism in all economic and social spheres. In addition to others industries, for the defence industry was also necessary the transition from products compatible with the Warsaw Pact to the products compatible with NATO. The obligation to change product specifications is a requirement applicable only to the defence industry. The other industries did only adaptations required by competitiveness. Given the above, the requirement of additional management effort appears for the defence industry. In the first section, the paper analyses several modern management methods that are present in the current literature. Based on this literature, the paper also aims to provide a management tool. This instrument is the QFD method. The paper presents the method of applying the Quality House matrix and the results that are obtained in a company from the defence industry.

» Keywords

management, QFD, efficiency, defence industry

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  • Zoltan MARKOS

Corrosion Test of the Siliconized and Chromo-Siliconized Steels

» Abstract

The paper presents the results of the comparative study of the corrosion tests to the siliconized and chromo-siliconized steels. The thermo-chemical treatments were made in powder mediums. The corrosion tests were made in different acids mediums (HCl, H2SO4 and HNO3), comparing the behaviours of the non-treated, siliconized and chromo-siliconized samples.

» Keywords

corrosion test, carbon steel, siliconizing, chromo-siliconizing

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  • Ioan MILOŞAN

Analyzing the Real Area of Contact Wear Using ANOVA

» Abstract

Austempering is a relatively new treatment in the field of ductile iron casting. This heat treatment was found to improve the ductile irons at high levels of strength, rendering ductile iron castings superior to steel forgings Austempered ductile irons usually contain a large quantity of retained austenite that can help to optimize their mechanical properties. Many of the properties of austempered ductile iron depend on the austenite which is retained following the bainite reaction. The studied cast iron had the following composition: 3.70 %C; 2.46 %Si; 0.56 %Mn; 0.038 %P; 0.009 %S; 0.25 %Mo; 0.23 %Cu; 0.065 %Mg. This cast iron was elaborated in an induction furnace. Nodular changes were obtained with the "In mold" method, with the help of prealloy FeSiCuMg with 10-16% Mg, added into the reaction chamber in a proportion of 1.1% of the treated cast iron. The structure in raw state is perlito-feritic typical for a cast iron with geometrically regular nodular form. The casted raw iron had the following mechanical properties: Rm = 650 N/mm2, HB = 180; KC = 10 J/cm2; A = 12 %. The paper presents an example of calculation for the one-way repeated measures applied for the results of an austempered ductile iron. This research has a number of objectives which can be started as follows: to calculate the real area variation (Ar) at the end of a bainitic S.G. cast iron wear process, study of the real wear contact values (Ar) variation, depending on the isothermal heat treatment parameters (Tiz and τiz ) and the micro hardness HV0.01 for FN = 4 kgf, the calculation for the one-way repeated measures applied for the results of the real area variation (Ar).

» Keywords

cast iron, heat treatment, wear, analysis of variance

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  • Monika MOGA, Gavrilă CALEFARIU, Laura BOGDAN, Laura OLTEANU

Indicators of Innovation at Enterprise Level

» Abstract

In addition to current management activities (planning, scheduling, execution, control) to deal with the changes occurring in the market, the companies (its management) are obliged to make major changes or improvements, to use either investment or innovations or, as often happens both. This paper deals with the second path, namely the effects of innovation processes in their broadest sense (research, development, and innovation). In the introduction are presented the major classes of innovations that may arise in a business: product, technology, management, and marketing. Any of these can have different effects, but positive, on the results of processes in the system. Further, by the depth analysis of the literature, some aspects for measuring the degree of innovation are presented. Finally, the innovation indicators are determined at enterprise level.

» Keywords

innovation, indicators, companies

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  • Ion NEAGOE

A New Reversible Blanking-Piercing Method

» Abstract

Blanking and piercing by cold precision shearing is a modern process for obtaining metal parts with high geometric and dimensional precision and high quality of the cut surface. The parts processing is carried out with special dies which offer conditions for clean-cut, by eliminating rough cracks in the shearing zone. In the industrial practice more precision shearing methods exist and are applied. Of these, the perfected method to produce high precision parts is by reversible blanking-piercing. However, due to application difficulties – the dies require for operating triple action special presses - this method has not spread at industrial scale. The paper presents a new reversible blanking-piercing method which eliminates this disadvantage. The die built according to this principle can be operated by double action presses available in all cold pressing workshops.

» Keywords

reversible blanking-piercing, die, metal sheet, high precision, high quality

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  • Cristian PISARCIUC, Dragoș CĂȚEANU

Improvement of Turning Performance through Statistical Process Control

» Abstract

This work presents some steps related to the implementation of statistical process control on a CNC turning centre. Due to the increasing need for a fast and reliable quality control system and in order to cope with the high output rates achievable in manufacturing industry today, some actions must be taken in order to a remain competitive on global market. The article is using data collected in turning process, presented through histograms and control charts, to improve the accuracy in order to reduce scrap. Several methods could be implemented, in order to accomplish the goal of satisfying the customer's demands, the detailed being the one with feed variation.

» Keywords

turning, feed, dimensional accuracy, statistical process control

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  • Ivan SHOPOV, Mariana BOTEVA

Machine for Rotary Molding of Plastic Type "Mussel"

» Abstract

Rotary molding has an important place among the main methods of processing of polymeric materials. In recent decades, the rapid development of this method has led to the achievement of high productivity, lower cost products, as well as improvement of the composition of the used polymeric materials. One of the most promising types of machine constructions for rotary molding machines are of type "mussel". The article deals with the technical requirements for the construction of a machine for rotary molding of plastic type "mussel". Characteristics of the design task are done and specified time to solve it by the method of "variation" is shown. 3D model of a machine for rotary molding of plastic was created and its design features were explained.

» Keywords

molding, rotary, machine, plastic

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  • Maria STOICĂNESCU, Ionuţ IONESCU, Ioan CIOBANU, Ion Sorin MUNTEANU

Aspects Regarding Simulation with Cylindrical Coordinates of Solidification Casting

» Abstract

Specialized software for solidification simulation of casting with rotational symmetry was conducted at the Transilvania University of Brasov. It is based on a 2D finite difference mathematical model with cylindrical coordinates. The software in cylindrical coordinates has the advantage that it simulates volume solidification of parts with rotational symmetry through 2D. This simulation provides a considerable reduction in the simulation duration. Depending on the part configuration and the network dividing step, the simulation time can be reduced by tens or hundreds of times. Another advantage of software in cylindrical coordinates is the simpler dividing of the system in finite elements. Also, it do accurate the representation of the contour for parts with rotational symmetry.

» Keywords

casting, solidification simulation, hot spot, mathematical modeling

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  • Ana VEȚELEANU

Thermal Characteristics of Composites with an Aluminium Alloy Matrix Reinforced with Silicon Carbide and Graphite

» Abstract

The aim of the paper is to analyse the thermal stability of hybrid composites (MMCH) with AlSi7Mg03+10%SiCp+3% Graphite, used in the automotive, aeronautic, microelectronic industries, by thermal analysis, type DIL (dilatometric analysis) and TGA (thermogravimetric analysis) correlated with techniques for structural investigation (SEM/EDS). The results obtained, show that the reinforcing elements influencing the thermal expansion phenomenon and the phase transformations. The linear expansion coefficient (CTE), determined utilizing the Kerner model, extended for hybrid composites, is similar to the one determined through experiments, being influenced by the thermal characteristics, the volume fraction of the matrix and the reinforcing elements. A similar influence was recorded in the case of thermogravimetric analysis.

» Keywords

composites, aluminium, SiC, graphite, thermal expansion

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  • Milka VICHEVA

Methodology for Identification of Aspects and Risk Assessment in Systems for Environmental Management

» Abstract

An analysis of the process of risk management according to ISO 31000 standard "Risk Management. Principles and guidelines" is done. The requirements of ISO 14001" Management systems in relation to the environment. Requirements and guidelines for implementation" for the identification of environmental aspects are analyzed and the guidelines for implementation according to ISO 14004 "Management systems in relation to the environment. General guidance on principles, systems and methods for deployment" are systematized. A review of the types of methods for risk analysis according to EN 31010: 2010 "Risk Management. Methods of risk assessment" is carried out. Taking into account the requirements of the new structure of the management systems a methodology for identification of aspects and risk assessment in environmental management system is developed; a sample of risk assessment is composed.

» Keywords

risk, environment management system, risk assessment, aspects of environment

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