• Transilvania University of Brasov, Romania

• Romanian Association for Nonconventional Technologies

CONTENTS

• Contents

• Authors Presentation

• Mohamed Seddik HELLAS, Rachid CHAIB, Ion VERZEA

Quantitative Risk Analysis Detailed Study of Thermal and Overpressure Risks Case Study

https://doi.org/10.31926/RECENT.2018.56.128

Abstract

Oil and gas companies generate high levels of risks because they process and store large quantities of flammable, explosive and toxic liquids and gaseous products. Actually, no country is immune to disasters related to the industrial installations of oil and gas complexes where several tragic experiences have caused significant human, material and environmental losses. Therefore, the importance of the rigorous monitoring of management procedures and the strict observance of industrial safety measures are required to ensure not only the reliability of the facilities themselves but also to protect the human resources. Locally, the catastrophic explosion of the liquefaction complex of Skikda in January 2004 caused 27 fatalities and 73 injuries and revealed many weaknesses in the risk prevention within Sonatrach. In order to master these phenomena several techniques and mathematical models of risk prediction have been developed. Among these methods, we find the Quantitative Risk Analysis (QRA), which is the objective of our work, whose objective is to evaluate the probability of damage caused by a potential accident. This method, initially developed in the field of transport and nuclear power, has been progressively adapted to the process industry, particularly in northern European countries for Seveso type installations. In this work, we are interested in the application of the QRA method to the LPG industrial zone located in Constantine, Algeria. The objective is the study of undesired events, their frequencies and their effects, including the probability of fatality or injury by thermal effect (1st degree burn, 2nd degree burn, deaths) and by overpressure (lung damage, eardrum rupture, head impact, whole-body displacement impact, building collapse, major structural damage, minor damages, breakage of window panes). The purpose is to estimate the individual risks and the societal risk, and to apply the measures that suitably deal with these estimates.

Keywords

QRA, probability of injury or death, thermal effect, overpressure effect, individual and societal risk

• Horațiu BULEA

Dimensional Variation of Aluminium Honeycomb Panel on Circular Cutting with Laser Jet Technology

https://doi.org/10.31926/RECENT.2018.56.137

Abstract

The cutting laser jet method can offer a suitable solution for manufacturing of aluminium honeycomb panel who are usually difficult to do. This paper presents the results of some experiments on laser jet cutting of circular holes into aluminium honeycomb panel, which can be further used for cutting holes in aluminium honeycomb panel. The main problem which occurs is the tapered shape of the hole, due to the mechanics of the process and the control of the kerf produced by the laser jet .The experiments considered several values of the main process parameters like power output, impulse frequency, fast feed rate on X and Y axes which have a direct influence on the part machinability. 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.

aluminium honeycomb panel, circular on laser jet cutting, dimensional variation of cut diameters

https://doi.org/10.31926/RECENT.2018.56.143

Long-distance in Romania is a different concept compared to international idea about this education form. In Romania, ARACIS applied a so-called blending learning, meaning that both students and teaching staff should have activities face-to-face, and more than this, these will be weekend activities. This is one of the biggest challenges of managing teaching staff in these study programs. Present paper underlines challenges and give some solutions to reduce abandon rate, from teaching staff point of view.

human resource management, high education, eLearning

https://doi.org/10.31926/RECENT.2018.56.151

This paper present a short overview regarding the Additive Manufacturing (AM) (also named Rapid Prototyping) technologies developed during last years. The principles of the most important technologies such as, Stereolitography (SLA), Selective Laser Sintering (SLS), Selective Laser Melting (SLM), Fused Deposition Modeling (FDM), Electron Beam Melting (EBM), and Laminated Object Manufacturing (LOM) are described in this paper. It was realized a comparison between the methods regarding the cost, materials and the complexity of the parts which are difficult to achieve by classical methods. It was presented a part regarding the structure of powder seen at scanning electron microscope (SEM) obtained by atomization and the surface morphology of the specimens fabricated from the powder obtained using argon and air. In addition, are presented some samples made by SLM and by EBM. About the cost, the researchers said that the equipment and services of additive manufacturing in 2020 would reach at 11 billion euros. AM can produce prototype parts with similar properties or better than conventional means.

additive manufacturing, selective laser sintering, selective laser melting, fused deposition, modeling electron beam melting

https://doi.org/10.31926/RECENT.2018.56.157

In this paper, we develop a method for estimating the direction of symmetry and the mass-centre coordinates of the image objects with symmetry. The proposed method is based on the estimation of the axes of symmetry of the image-object by means of its enclosing equivalent ellipse. The coordinates of the mass-centre and the directions of the main axes of the equivalent ellipse are estimated with the Radon transformation method. Within the paper, we propose the implementation of a forgetting-factor-type 2D filter that improves the accuracy of the estimate, especially for the blurred and noisy images.

image analysis, Radon transformation, direction estimation, digital image processing

https://doi.org/10.31926/RECENT.2018.56.164

Organizations of all types and sizes face a number of risks that may affect the achievement of their goals. These goals can relate to a range of organization activities, from strategic initiatives to operations, processes, and projects. Risk assessment provides decision-makers and responsible parties with a better understanding of the risks that could affect the achievement of the objectives. The paper presents the main method to be used in risk assessment, namely risk analysis. It provides a basis for deciding on the most appropriate approach to be used to address the risks.

risk, safety, standards, risk management, risk assessment methods-technique

• Valentin DITU

Quality Analysis of Roughing Reamers That Use WNMG080408–P30 Mechanical Fixed Cutting Inserts

https://doi.org/10.31926/RECENT.2018.56.169

Abstract

Due to the many advantages, the using of mechanical fixed cutting inserts extents to development of different cutting tools, like the reamers. Roughing reamers with switchable inserts that use WNMG mechanical fixed inserts are used for both enlarging and reaming. Knowing the value of the electrical current at cutting is important because it provides much information regarding the quality appreciation of the tool, which is determined by the tool life of the used cutting inserts. In this paper, there are experimentally determined values of the electrical current at cutting at processing 1C45 steel with roughing reamers in the range of diameters of 20÷153 mm that use at cutting edge mechanical fixed WNGB080408–P30 cutting inserts.

Keywords

cutting, enlarging, electrical current at cutting

• Ramona CLINCIU

Analysis of the Probability of Acceptance of the Normality Hypothesis by the Goodness-of-Fit Tests

https://doi.org/10.31926/RECENT.2018.56.173

Abstract

The paper presents and emphasizes the behaviour of different goodness-of-fit tests, towards the acceptance of the normality hypothesis. The goodness of fit tests considered are general goodness-of-fit tests - Kolmogorov-Smirnov, Cramer-von-Mises, Anderson-Darling, and normality goodness-of-fit tests - Lilliefors, Shapiro-Wilk, D'Agostino, Massey, Filliben, Z, Cox. These goodness-of-fit tests are conducted on normally distributed data in order to test the normality of the data. The need for testing the normality of the data appears especially in metrology, for the analysis of the metrological reliability. General metrology uses especially the normal distribution, despite the fact that positive and asymmetrical distributions (e.g. Weibull distribution) are frequently met in the analysis of the metrological reliability. In these cases, it is necessary to perform goodness-of-fit tests in order to ascertain that the normal distribution fits the data. The quality of the results depends on the goodness-of-fit test, which was chosen to determine if the normal distribution fits the data best.

Keywords

metrological reliability, goodness-of-fit tests, normal distribution

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