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Vol. 19 (2018), No. 2 (55), 2018

 

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

CONTENTS



  • Mariana FRATU, Iulian Dorin SBANCA

Modern Railway Signaling and Control Systems

https://doi.org/10.31926/RECENT.2018.55.063

Abstract

Nowadays, railway signaling is based on automatic blocks, which does not require manual intervention. The modern railway signaling systems currently used today are intelligent and automatic high-performance systems. A line equipped with automatic blocks (interlocking) is divided into sections of length not shorter than the braking distance of the faster train running on the route. The function of detecting the presence or transit of the vehicles in a particular section can be realized through different equipment. In this paper, we recommend the radio communication network as new solution for detecting the presence of the vehicles in a particular section. For the development of High Speed Lines it become essential to ensure high performances regarding interoperability and safety.

Keywords

automatic train protection, interlocking, railway signaling and communication, GSM-R

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  • Dorin Ioan FELDIOREAN, Mircea Horia ȚIEREAN

Studies on the Carburizing Process of AISI 8620 Steel Obtained by MIM Technology

https://doi.org/10.31926/RECENT.2018.55.070

Abstract

These experiments are aimed to highlight the differences that occur in the carburizing process of the metal parts obtained by the MIM technology (Metal Injection Molding), compared to those obtained from round cold drawn bar by CNC and conventional cutting machining (AISI samples). For this purpose, two categories of complex geometry pieces, components of the sewing machine's rotary hook, were used. After tests was observed that depth of the carburized layer is lower for the MIM parts. Using a 5 kg load, the Vickers hardness measured on the MIM parts surface turned out to be smaller than the AISI samples. Decreasing the load force, the Vickers hardness measured on the MIM sample surface after heat treatment start to increase. In order to obtain the desired hardness after the grinding process, the MIM samples tempering temperature was 130 °C and for the AISI samples was 170 °C. After the grinding machining, it was also observed that MIM parts had a significant hardness loss compared to the others. These results can be explained due a lower density of the MIM parts (≥7.4 g/cm2) compared to AISI parts (7.81 g/cm2) and lower content of Cr and Mn alloying elements.

Keywords

MIM, heat treatment, hardness, layer, density

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  • Maria STOICĂNESCU, Aurel CRIȘAN, Mihai Alin POP, Ioan CIOBANU

Experimental Verification of a Software for Simulation of Heating Metallic Parts in Solar Furnaces

https://doi.org/10.31926/RECENT.2018.55.077

Abstract

Lately, experimental research has been carried out on the use of concentrated energy solar furnaces for the thermic processing of materials. On this line, at Transilvania University a software was developed for simulating the heating of metal parts in such furnaces. In a previous paper was presented the mathematical model that underpinned the realization of this software. This paper presents the results of experimental validation of this software. There are compared the heating curves of a test piece, obtained by simulation (with this software), with the heating curves obtained by experiment. The results confirmed the validity of the software. It is concluded that the software can be used to simulate on the computer the working parameters of the concentrated power flow solar furnaces for the thermic processing of some metallic parts (e.g. heat treatments in volume, surface heat treatments, melting, welding, surface coatings, etc.).

Keywords

heating simulation, solar furnaces, heat treatment, software verification, heat treatment, solar energy

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  • Nicolae BOIAN

Management of Small Business' Recovery

https://doi.org/10.31926/RECENT.2018.55.089

Abstract

The present paper is a systematization of small business’ recovery management through the scientific modelling of the phenomenon and the estimation of its inertia to the strategic adaptation measures. Strategic modelling in recovery management aims to achieve a scientific justification in favour of the CEO's decision to start a recovery business plan. The method used in evaluation is the criterion type with parameter weighting based on their potential on business recovery based on a diagnosis personalized model containing technical and economic domains, criteria and indicators. Starting from a specific model, personalized model results by eliminating the criteria that are irrelevant from the point of view of the enterprise's activity, the objectives of business recovery or those whose cost exceeds the value of the information obtained. According to the proposed method, each domain is weighted by the resistance to change generated, through a coefficient ri. Also, each criterion is weighted considers its potential for recovery over the domain it belongs to, through a coefficient pi. A significance score of criteria are calculated by multiplying the criterion status (Pi) with these two coefficients establishing a hierarchy of criteria in the recovery plan. Finally, the paper provides an interpretation of the criteria contribution to the recovery plan, based on the calculated score. A case study is presented for how to apply the method.

Keywords

recovery management, diagnosis, recovery plan, criterion, coefficient

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  • Mouaadh HASSANI, Rachid CHAIB, Ramdane BOUZERARA

Reduction of the Vulnerability Zone of a Major Industrial Risk. Case of BLEVE in LPG Storage Sphere Hassi R'Mel, Algeria

https://doi.org/10.31926/RECENT.2018.55.097

Abstract

Main brands of dental implants demonstrate superior features confirmed for years now. Among them, specific mechanical properties of materials that dental implants are made of, and mechanical properties of the parts themselves, are together with surface treatments, the most important traits that stay behind their success. The comparison of the main brands of dental implants, was made by means of objective analysis (roughness measurement, SEM microscopy with identifying chemical composition, tear tests, etc.). The study tried to penetrate into the depth of crystal structures and chemical formula behind good behaviour that was demonstrated in clinical applications. The study demonstrates the diversity of titanium alloys used in the production of dental implants and opens opportunities of new formulas. New proportions between the percentages of aluminium or titanium and vanadium, and other elements use (zirconium, niobium, etc.), will make possible to obtain new implants with superior performance.

Keywords

risk reduction, major risks, vulnerability, intensity, ALOHA simulation, BLEVE LPG and oil-&-gas industries

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  • Bogdan ARSENE, Gavrilă CALEFARIU

Trends and Challenges of Manufacturing Management in Industry 4.0

https://doi.org/10.31926/RECENT.2018.55.108

Abstract

Today’s globalization is creating and is bringing new opportunities for sustainable development. New emergent markets are rising, thus more environment friendly new innovative solutions for meet current demand are released. The global economy is facing today with many challenges and for manufacturing systems in order to be competitive on the global market it is mandatory to innovate permanently. Industry 4.0 (I4.0) with its main component smart factory i.e. factory of the future may be seen like an innovation in manufacturing field. Factory of the future (FoF) will be driven by intelligent manufacturing systems, characterized by smart machines, smart equipment, smart operators and smart products with the purpose to achieve mass customization, industrial growth and added value. The newest information and communication technologies play a key role in development of the smart factory and together with the physical devices lead to creation of so called Cyber-Physical System (CPS) which is the core of FoF. This paper contains a systematic study of the researches undertaken in the field of I4.0 and reveal the trends and the challenges of manufacturing management both those presented by literature and those resulting from direct researches of the authors, in four categories.

Keywords

trends, challenges, manufacturing management, Industry 4.0, CPS

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