Engenharia e Gestão Industrial

Random generators or stochastic engines are a key component in the structure of metaheuristic algorithms. This work investigates the effects of non-Gaussian stochastic engines on the performance of metaheuristics when solving a real-world optimization problem. In this work, the bacteria foraging algorithm (BFA) was employed in tandem with four random generators (stochastic engines). The stochastic engines operate using the Weibull distribution, Gamma distribution, Gaussian distribution and a chaotic mechanism. The two non-Gaussian distributions are the Weibull and Gamma distributions. In this work, the approaches developed were implemented on the real-world multi-objective resin bonded sand mould problem. The Pareto frontiers obtained were benchmarked using two metrics; the hyper volume indicator (HVI) and the proposed Average Explorative Rate (AER) metric. Detail discussions from various perspectives on the effects of non-Gaussian random generators in metaheuristics are provided.

Organizations are subject to decisions regarding the location of facilities and the required minimum number of the facilities to satisfy certain needs. In this regard, p-median and set covering problems are discussed in a way that they are not adequate under some real-world scenarios. Hence, this paper introduces an optimization model for providing the required number of facilities and their locations to serve different sets of nodes (i.e., departments) within a specified distance range. A deterministic integer programming model is developed and implemented on a real-world problem.

In the performance of a spindle CNC system, its bearings play an important role. Many problems arising in a spindle CNC operation are linked to bearing faults. In this project, the accuracy of the instruments and devices used to monitor and control the motor system is highly dependent on the dynamic performance of its bearings. Thus, fault diagnosis of a motor system is inseparably related to the diagnosis of the bearing assembly. In this paper, bearing vibration frequency features are discussed for spindle CNC of bearing fault diagnosis. This paper then presents an approach for life prediction of spindle CNC rolling bearing using nonlinear regression analysis. Vibration data are used to assist in the design for controlling and rolling bearing fault diagnosis strategies. Then our results obtained indicate that controlling and rolling bearing fault diagnosis can be effective agents in life prediction and diagnosis.

The unstable growth of fatigue cracks brings a material or structure to catastrophic failure. It is better than any fatigue crack does not initiate in engineering applications. However, fatigue crack initiation cannot be prevented in some applications because maintaining their efficiency or performance is important factor for usage. When a crack is initiated in machine equipment, it should be repaired or the equipment replaced. Sometimes, the cracked material was repaired and many repair methods were proposed. In this report, a simple method of stopping crack growth is proposed to apply to a cracked plate with varying thickness. The stop-hole and crack arrester were applied in the present method.

Injection molding is one of the most important forming processes for thermoplastic polymers. Setting the injection molding parameter such as injection pressure, injection speed, cooling time and packing pressure plays a very important role in controlling the quality of the products forming by injection molding process. Taguchi approach is a widely used technique for optimizing the molding process parameters. This paper presents a simple and efficient way to study the influence of injection molding parameters on defects percentage. Using Design of experiments and Taguchi approach, the significant parameters are optimized to minimize the defects percentage of the most common defects (inverted label and incomplete plastic filling) that appeared in thin walled containers for food packaging. The results of the experimental study indicate that Injection speed and Injection pressure are the dominant factors determining the quality. The injection speed of 300 CCm/Sec give lower inverted label defect and the injection pressure of 2000 bar give lower incomplete filling defect.

Purpose: This paper deals with four layers approach for developing a tool for assessing engineering systems thinking. Every engineer and, in particular, industrial and systems engineer needs a systems view that enable to perform systems engineering tasks successfully. The paper’s purpose is to present a tool for assessing systems thinking of industrial and systems engineers. The tool may be used for industrial and systems engineering workplace selection and development, developing industrial and systems engineering curriculum, education, and training programs, as well as a standard tool for assessing industrial and systems engineers’ competencies. Design/methodology/approach: We have to find a way to evaluate a systems view or in other words, a high capacity for engineering systems thinking (CEST) Since there is no known way of directly ‘measuring’ systems thinking in general and CEST, in particular, an indirect method is needed. This paper proposes an idea for developing an indirect means, i.e. a questionnaire for assessing the CEST of industrial and systems engineers. The idea is composed of four logic layers that will be presented in the paper. Findings and originality/value: Eighty-three, which later aggregated to thirty-four competencies, of successful industrial and systems engineers were identified in a previous study. They can be classified into four categories – ten cognitive competencies, eleven abilities, ten individual traits and three dealing with multidisciplinary knowledge and experience. Thus, the content validity of the proposed tool can be achieved by basing its items on the finding in the latter study. Additional studies were done on systems thinking among industrial and systems engineers and among engineers from various disciplines. One of the findings of a previous study is that in order to be a successful industrial and systems engineer, one must have both a will and interest in being an industrial and systems engineer. The three components discussed here – success in an industrial and systems engineering position, interest in industrial and systems engineering positions and CEST – are all interrelated. The will and interest to be an industrial and systems engineer means basically the desire and interest to be involved in job positions that require CEST. In other words, we may hypothesize that there is a high positive correlation between the engineering systems thinking extent (CEST) of an individual and his/her interest in what is required from successful industrial and systems engineers. Research limitations/implications: Owing to time constraints, the research only included a limited sample of industrial and systems engineers. In order to enlarge the external validity of this research, we should ask more subjects from different engineering disciplines and use additional tools such as interviews and observations. Originality/value: The framework of this research is unique in term of its new approach and evaluation processes

Magnesium nitride (Mg3N2) has gained extensive attention due to its catalytic and optoelectronic properties. The present investigation was aimed to evaluate the effect of biofield energy treatment on physical and thermal properties of Mg3N2 powder. The Mg3N2 powder was divided into two parts i.e. control and treated. The control part was remained as untreated and the treated part was subjected to the Mr. Trivedi’s biofield energy treatment. Subsequently, the control and treated Mg3N2 samples were characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). The DSC results showed the specific heat capacity of 2.24 Jg-1°C-1 in control, which increased upto 5.55 Jg-1°C-1 in treated Mg3N2 sample. The TGA data revealed that the onset temperature for the formation of magnesium oxide, possibly due to oxidation of Mg3N2 in the presence of air and moisture, was reduced from 421.0°C (control) to 391.33°C in treated sample. Besides, the XRD data revealed that the lattice parameter and unit cell volume of treated Mg3N2 samples were increased by 0.20 and 0.61% respectively, as compared to the control. The shifting of all peaks toward lower Bragg angle was observed in treated sample as compared to the control. The XRD diffractogram also showed that the relative intensities of all peaks were altered in treated sample as compared to control. In addition, the density of treated Mg3N2 was reduced by 0.60% as compared to control. Furthermore, the crystallite size was significantly increased from 108.05 nm (control) to 144.04 nm in treated sample as compared to the control. Altogether data suggest that biofield energy treatment has substantially altered the physical and thermal properties of Mg3N2 powder. Thus, the biofield treatment could be applied to modulate the catalytic and optoelectronic properties of Mg3N2 for chemical and semiconductor industries.