Metallurgical and Materials Engineering (E-Journal)
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Maturity level of predictive maintenance application in small and medium-sized industries: Case of Morocco
Get PDFIn order to remain competitive in the long term and to push the company's efficiency to its limits, entrepreneurs are more and more open to the idea of integrating into Industry 4.0 aiming mainly at filling the important downtimes and the associated productivity losses by implementing predictive maintenance. This concept, common in developed countries, is much less widespread in Morocco and even less in small and medium-sized Moroccan companies. The objective of this article is to study the maturity level of predictive maintenance in Moroccan small and medium-sized enterprises, through a questionnaire validated by experts and made available to several companies. Valid data from 115 companies throughout the kingdom operating in different sectors were collected and processed by descriptive and factorial analysis under SPSS software. The results obtained show that only 33% of our sample were able to implement predictive maintenance, and that the expected benefits of this approach are the minimization of downtime at 96.5% and the increase in productivity at 94.8%, The main challenges observed are the lack of team motivation and a corporate culture unsuited to digitalization, which represents 42.277% of the total variance, lack of financial resources at 12.916% of the total variance and lack of data protection at 11.644% of the total variance. This analysis indicates that the level of maturity regarding the application of predictive maintenance in Moroccan small and medium-sized companies is low, these rates can be used to improve the root causes
Experimental Analysis of Fatigue Crack Path for Strained Functionally Graded Materials
Get PDFThis paper experimentally discusses crack paths in strained Functionally graded materials under constant loading conditions and vibration fatigue. The objective is to synthesize the body of knowledge on the stability of FGM. The article presents the development, production, and characterization of multi-Al (aluminum), Ni (nickel), and Titanium alloys. FGM it was successfully modified using the powder metallurgical technique. Five-layer FGM samples frequently utilize (Al, Ni), on one end and (Al-Ni-Ti) on the first. FGM sample mechanical characteristics have been investigated using wear and Fatigue testing. The Al/Ni/Titanium FGM compact specimen approaches the yield stress and ultimate stress values, which is regarded as a significant improvement in mechanical qualities with less weight. The test findings are for a constant amplitude load fully reversed with zero mean stress. The stress life approach examined three samples' fatigue characteristics and natural frequency under random vibration
New smart actuator based on shape memory alloys for avoiding overheating and preventing fire in electronic devices
Get PDFIn the past few years, fire incidents in electronic systems have become frequent and caused many losses of life and property. Consequently, various studies have been conducted in order to establish effective ways to avoid fire caused by electrical devices. In light of the fact that electrical sensors frequently get damaged, it is crucial to develop a smart switch that can detect and control off electrical current during an unexpected heat increase or fire incident. In this study, a numerical study that aims to develop a smart actuators combined with electrical devices in order to protect electronic system from fire accidents has been conducted. The proposed smart actuator is based on the shape memory alloy (SMA), which has a robust thermomechanical coupling that reacts to the temperature variation and generates an important mechanical loading. Using the SMA actuator between an electrical power source and the device will avoid any incident related to the temperature increase. Therefore, mathematical modelling has been conducted to adjust the smart actuator with any electrical device, with rules that will be developed to increase the actual detection rate. The simulation results of the proposed fire detection system has been compared with several current methods. The results show that the proposed engineering is very promising and can respond to a temperature change in 0.2 s and generate a total deformation of about 8%. The results show that the suggested method has a higher fire detection rate that can reach 90% for detection
Utilizing Homer Power Optimization Software for A Techno-Economic Feasibility, Study of a Sustainable Grid-Connected Design for Urban Electricity in, Khartoum
Get PDFHOMER (Hybrid Optimization of Multiple Electric Renewable) streamlines the design of distributed generation (DG) systems for a variety of grid-connected and off-grid applications. In Sudan, it is difficult to acquire an effective photovoltaic array for residential use due to a lack of energy consumption in power generation and access to technological, social, and environmental constraints. A model of a low-energy, solar-powered house that is suitable for Sudanese social and economic norms requires a high-quality architectural design. Method Using the HOMER software, the charge advantage analysis of a hybrid system was studied and assessed using the value for each kilowatt of grid-connected systems or utility grid. The simulation results have been presented as the most efficient and cost-effective method for achieving various home counts. At the current price, the hybrid system has a refund term of about fifty-four years. If turbine prices in Khartoum decline, the overall cost of energy will be reduced
Structure and Properties of Graphite-Molybdenum Brazed Joints
Get PDFThe paper presents the results of X-ray microspectral studies of dissimilar brazed joints of molybdenum with graphite. It is shown that during active brazing of graphite with molybdenum, mutual diffusion processes occur, and the adhesion-active brazing filler metals penetrates into graphite, and interacts with it, which leads to the formation of carbide phases. When using the Ti-Cr-V and Cu-Ti-Ni systems brazing filler metals, titanium carbides are formed. The zirconium carbides are formed, when using the brazing filler metals based on the Zr-Pd(Mo) systems and the CxMey(Mo, Cr) carbides are formed using the brazing filler metals of the Pd-Ni-Cr-Ge system. The results of tests for three-point bending showed that the using of Pd-Ni-Cr-Ge brazing filler metals provides stable strength at the level of 34-37 MPa, destruction occurs along graphite
Network of Water Problems in the Press of Mexico City During the COVID-19 Era
No full textThe pandemic generated containment and mitigation policies, as well as distancing and confinement strategies that limited the supply of water resources to social sectors. Residential areas- The offer is maintained, but with an increase in rates. Marginalized areas were subsidized and exempted from paying for an increasingly intermittent supply. The anti-COVID-19 policies guided water policies in two ways: The first consisted of disseminating anti-COVID-19 policies in water management agencies. Another second consisted of the autonomy of the institutions and their disassociation or agreement with the anti-COVID-19 policies. In this way, the literature from 2020 to 2023 around anti-COVID-19 policies in their water dimensions, registers problems of scarcity, famine and unsanitary conditions. Scarcity had already been observed in marginalized sectors, famine in residential neighborhoods, but unsanitary conditions were appreciated in migrant communities. In fact, the type of exposure to occupational hazards determined the health status of the migrants. The water problems were recorded in the circulation press to highlight the asymmetries of the anti-COVID-19 policies in the public and private sectors, as well as in the political and social actors. The objective of the study was to reveal the network structure of relationships between nodes and edges related to press releases on water issues. A documentary, cross-sectional and retrospective study was carried out with national circulation newspapers: El País, El Reforma, La Jornada and El Universal, considering the water problems of scarcity, unsanitary conditions and famine. The results show a structure of nodes where the water problems were initiated by La Jornada and ended by El Reforma. Both findings are relevant considering the ideology of the newspaper. La Jornada, a newspaper identified with the political ideology of the left, began the diffusion of water problems in a city administered by a government of the same ideology. El Reforma, a newspaper designated by the executive as a spokesperson for the opposition ideology, culminates the network of notes on water problems. In other words, regardless of the type of political ideology attributed to newspapers, the problems of scarcity, unsanitary conditions and famine are spread. In relation to the state of the art where it is shown that ideology does not influence the establishment of the agenda, the present work corroborates and recommends expanding the study to other entities administered by the opposition such as the cities of Guadalajara and Monterrey
Minimization of the stress concentration in Formed Parts through Non-Parametric Optimization
Get PDFParametric and non-parametric are the main optimization methods that are used in various industrial fields. In non-parametric optimization, the process of manipulating the node locations (shape optimization) or removing mass without changing the node locations (topology optimization) is adopted to achieve a desired objective. This structural optimization is formulated as a non-parametric problem, and for analysis purposes, ABAQUS/CAE software is adopted for this approach. Manufacturing process like forming is always linked with stress concentration, especially in the sharp ends and variable cross sections like holes and fillets. The problems of representation and finding the optimal and better structural design of some known quantities such as reactions, loads and masses is not easy. A large deflection may be induced in a structure when experiencing severe mechanical loads. In this work, the numerical method has been presented to investigate a method for optimization of formed parts geometry. Numerical examination confirmed that high-stress concentrations are generated in many places. Material distribution is highly influenced by nonlinearity and the new layout will result in intermediate densities. In such cases, the nonlinear elasticity like nonlinear strain must be considered. As a result, the non-parametric optimization can offer good design flexibility to use the existing model with ease of setup and without the need for parameterization. It can provide a conceptual design that can reduce the structure's weight to the maximum extent in the early design stage. This work is going to optimize the design of the formed plates by reducing the volume while maximizing its stiffness. As a recommendation, in order to provide an attractive approach with suitable levels of structural performance, the combination of both optimization methods is the short way to achieve this aim
Surface cracks growth for superalloy in a round bar under different loading
Get PDFThe main objective of this paper is to experimentally and numerically detect the surface cracks in the round bar for Ni-Al- 315 steel superalloy and calculate the crack depth which induces the sintering of these alloys. Several factors have contributed to surface defects, such as metallurgical defects and notches. The surface crack orientation can be estimated at the observed crack increase by using displacement. Various crack aspect ratios, a/b, ranging from 0.0 to 1.0, and relative crack depth, a/D, ranging from 0.2 to 0.4, are considered. The superalloy (Ni, Al and 315 steel) has been successfully modified utilizing the powder metallurgical process. The specimens are typically made up of Six layers, starting with (Al, Ni) across one side and ending with (Ni-Al- 315 steel) on another. Transmission electron microscopy (SEM) Instrument analysis has been used to detect the surface cracks and analyze the microstructure of superalloy used in detail using the X-pert analytical program
Review Of Grain Refinement Performance Of Aluminium Cast Alloys
Get PDFImproving the utilization of aluminum grain refinement in industrial settings is a continual point of focus for research. Grain refinement serves the dual purpose of not only achieving a fine grain size, but also enhancing the mechanical properties of materials. Numerous researchers have dedicated significant efforts over the last decades to explore the grain refinement of aluminium alloys. There have been a number of studies relating to the mechanisms that explains the observed phenomena associated with grain refinement. The most commonly employed are grain refiners based on Al–Ti–B system. However, a limited efficiency of these grain refiners on aluminium silicon alloys with excessive Si and the effect of alloying elements have been noticed. The review examines the impact of the factors influencing grain refining behaviour of master alloys, including the effects of poisoning elements such as Si, Mg, Zr, and Sr. A large grain refiners used for enhancing the properties of aluminium silicon alloys are reviewed. An overview of new refiners has been given. Also, procedures for assessment of grain refinement have been examined.  
Preliminary study of two antique Illyrian helmets (V-IV B.C.) excavated in northwest and northeast of Albania
Get PDFThis study combines several analytical techniques to preliminary investigate two Illyrian helmets (V-IV century B.C.) excavated in Nënshat (Shkodra, northwest Albania) and in Krumë (Has, northeast Albania). They were stored in the Center of Albanian Studies, after excavation in 1963 in damaged conditions but have never been studied until now. The aims of this paper are the investigation of the helmets’ alloy and production technique; hence SEM-EDS, OM and Vickers microhardness tester were used to study the elements content, microstructure inclusions and its characteristics due to the production process. The Illyrian helmets alloy resulted Cu-Sn with less than 1% of Fe and As. The microstructure was composed by straight and bended twins, with 160.5 and 169.6 mean Vickers microhardness values, suggesting that these objects’ alloys were casted, annealed and cold worked to obtain the final distinctive shape. Elements such as S, Si, Fe can originate from the copper mineral used for the alloy production. This paper is part of a campaign in Albania to better understand the past with the use of physical analytical techniques