Role of cube texture on toughness variation of electric resistance welded steel

Properties changes of an X52 microalloyed steel processed by a full-scale industrial electric resistant welding (ERW) equipment was studied. Lack of proper toughness level in the weld zone was investigated. Results show that the low toughness value could only be satisfactorily addressed after a two-stage annealing process. {100} pole figures for each processing step revealed a completely random texture for the initial plate. However, after the ERW process, a textured structure with the main components of brass, S and copper was obtained. Texture components were substantially weakened after the second stage of annealing and instead a cube texture was developed which could explain satisfactory level of toughness for the ERW pipe after conducting the two-step annealing process.     

Security anomaly detection in software‐defined networking based on a prediction technique

Nowadays, software‐defined networking (SDN) is regarded as the best solution for the centralized handling and monitoring of large networks. However, it should be noted that SDN architecture suffers from the same security issues, which are the case with common networks. As a case in point, one of the shortcomings of SDNs is related to its high vulnerability to distributed denial of service (DDoS) attacks and other similar ones. Indeed, anomaly detection systems have been considered to deal with these attacks. The challenges are related to designing these systems including gathering data, extracting effective features, and selecting the best model for anomaly detection. In this paper, a novel combined approach is proposed; this method uses NetFlow protocol for gathering information and generating dataset, information gain ratio (IGR), in order to select the effective and relevant features and ensemble learning scheme (Stacking) for developing a structure with desirable performance and efficiency for detecting anomaly in SDN environment. The results obtained from the experiments revealed that the proposed method performs better than other methods in terms of enhancing accuracy (AC) and detection rate (DR) and reducing classification error (CE) and false alarm rate (FAR). The AC, DR, CE, and FAR of the proposed model were measured as 99.92%, 99.83%, 0.08%, and 0.03%, respectively. Furthermore, the proposed method prevents the occurrence of excessive overload on the controller and OpenFlow.     

On the Stability of Reversely Formed Austenite and Related Mechanism of Transformation in an Fe-Ni-Mn Martensitic Steel Aided by Electron Backscattering Diffraction and Atom Probe Tomography

The stability of reversely formed austenite and related mechanism of transformation were investigated against temperature and time in an Fe-9.6Ni-7.1Mn (at. pct) martensitic steel during intercritical annealing at a dual-phase (α + γ) region. Dilatometry, electron backscattering diffraction (EBSD), atom probe tomography (APT), and X-ray diffraction (XRD) were used to characterize the mechanism of reverse transformation. It was found that under intercritical annealing at 853 K (580 °C), when the heating rate is 20 K/s (20 °C/s), reverse transformation takes place through a mixed diffusion control mechanism, i.e., controlled by bulk diffusion and diffusion along the interface, where Ni controls the diffusion as its diffusivity is lower than that of Mn in the martensite and austenite. Increasing the intercritical annealing to 873 K (600 °C) at an identical heating rate of 20 K/s (20 °C/s) showed that reverse transformation occurs through a sequential combination of both martensitic and diffusional mechanisms. The transition temperature from diffusional to martensitic transformation was obtained close to 858 K (585 °C). Experimental results revealed that the austenite formed by the diffusional mechanism at 853 K (580 °C) mainly remains untransformed after cooling to ambient temperature due to the enrichment with Ni and Mn. It was also found that the stability of the reversely formed austenite by martensitic mechanism at 873 K (600 °C) is related to grain refinement.     

A new approach for prioritization in fuzzy AHP with an application for selecting the best tunnel ventilation system

Tunnel design and construction consist of multiple sub-processes among which the selection of proper ventilation system is one of the most important issues. In this problem, several criteria are included in the process; therefore, multi-attribute decision making (MADM) tools should be used for the purpose. One of frequently used MADM methods is fuzzy analytic hierarchy process (AHP) in which uncertainty is also taken into account in the decision-making process. In this paper, using fuzzy data envelopment analysis, a new approach is presented for ranking the alternatives in fuzzy AHP. In this approach, the fuzzy nature of data is kept in all steps of the approach. Furthermore, to determine the consistency level of fuzzy pairwise comparison matrix, an appropriate index is used. Then, the proposed approach is used for selecting the best tunnel ventilation system.     

Electrocatalytic oxidation of methanol on Ni and NiCu alloy modified glassy carbon electrode

Nickel and nickel–copper alloy modified glassy carbon electrodes (GC/Ni and GC/NiCu) prepared by galvanostatic deposition were examined for their redox process and electrocatalytic activities towards the oxidation of methanol in alkaline solutions. The methods of cyclic voltammetery (CV) and chronoamperometry (CA) were employed. The cyclic voltammogram of NiCu alloy demonstrates the formation of β/β crystallographic forms of the nickel oxyhydroxide under prolonged repetitive potential cycling in alkaline solution. In CV studies, in the presence of methanol NiCu alloy modified electrode shows a significantly higher response for methanol oxidation. The peak current of the oxidation of nickel hydroxide increase is followed by a decrease in the corresponding cathodic current in presence of methanol. The anodic peak currents show linear dependency with the square root of scan rate. This behavior is the characteristic of a diffusion controlled process. Under the CA regime the reaction followed a Cottrellian behavior and the diffusion coefficient of methanol was found to be 2 × 10⁻⁶ cm² s⁻¹ in agreement with the values obtained from CV measurements.     

Competitive performance improvement by operational budget allocation using ANFIS and fuzzy quality function deployment: a case study

A budget is a detailed and comprehensive plan estimated to use a company’s resources over a specific period, and a primary purpose of budget allocation is to drive all activities towards organizational goals. But it seems, often, there is no logical and coherent relationship between overall objectives and action plans. This paper has drawn a consistent relationship between an organization's strategic plans to operational budgeting in a competitive environment. According to the step-by-step model proposed in this article, a strategic plan’s importance considers the main competitors of the market as an external environment factor and a balanced scorecard factors as an internal environment. Both are calculated by an artificial neuro-fuzzy inference systems approach to outshine competing companies. Then, sub-progress must be hierarchically determined in specific plans. In passing, a fuzzy quality function deployment method translates a strategic plan’s weight to detailed task importance (as the smallest component of an operational program) at the mercy of four houses of a quality matrix. An operational budget is allocated to programs for propagating strategic plans in a competitive environment. Finally, a case study in an automobile industry is presented and discussed to illustrate the application of the developed pattern.     

Performance analysis of a passive cooling system using underground channel (Naghb)

The present study, aims at introducing and studying the effect of an old and specific type of house cooling system in Bam city. Primary of the system is similar to Baud-Geers (wind tower) but in the mentioned system, there is an additional channel connected to Baud-Geer which is called Naghb. Naghb in fact is an underneath channel that uses the ground humidity to cool the air. Baud-Geer input wind passes through the Naghb and evaporation cooling makes it cooler in the Naghb. Therefore, the cooling effect of Baud-Geer enhances. Unfortunately, all of Baud-Geers and Naghbs in Bam destroyed in the earthquake happened on December 26, 2003 and only ruins of them are left, hence in order to study Naghb performance in the present study, a one-dimensional model is presented and the conservation equations of energy, mass and momentum have been solved simultaneously. In order to evaluate the model, a simple experimental setup is made on the basis of real dimensions of Naghb. The model results reveal the ability of Naghb in cooling the air during hot and dry months in Bam.     

Experimental Investigation to Optimize Tool Life and Surface Roughness in Inconel 718 Machining

In addition to the cutting conditions, the surface quality is also affected significantly by a worn tool in machining processes. Identification of the desirable tool life so that the surface quality is maintained within a desirable level is an essential task, especially in the machining of hard materials. In this paper, an optimal tool life and surface quality were identified in the turning operation of Inconel 718 Superalloy by means of experimental investigations and intelligent methods. First, the effect of machining time (MT) at the different cutting parameters was widely investigated on the surface roughness using the neural network model. Then, the modified Non-dominated Sorting Genetic Algorithm (NSGA) was implemented to optimize tool life and surface roughness. For this purpose, a new approach was implemented and the MT was taken into account as the input and output parameters during the optimization. Finally, the results of optimization were classified and the suitable states of the machining outputs were found. The results indicate that the implemented strategy in this paper provides an efficient approach to determine a desirable criterion for tool life estimation in machining processes.