scholarly journals Defectoscopic and Geometric Features of Defects That Occur in Sheet Metal and Their Description Based on Statistical Analysis

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1851
Author(s):  
Ihor Konovalenko ◽  
Pavlo Maruschak ◽  
Halyna Kozbur ◽  
Janette Brezinová ◽  
Jakub Brezina ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Sheet Metal ◽  
Geometric Structure ◽  
Rolling Process ◽  
Morphological Features ◽  
Additional Analysis ◽  
Geometric Features ◽  
Additional Information ◽  
Steel Strips ◽  
Technological Defects

Features of the defect class “scratches, attritions, lines”, their geometric structure, and their causes are analyzed. An approach is developed that defines subclasses within this class of technological defects based on additional analysis of morphological features. The analysis of the reasons for these subclasses allows additional information to be obtained about the rolling process, identifying additional signs of defects, regulating the rolling conditions of steel strips more accurately, and diagnosing the equipment condition.

Research on Transition Zones of Spherical Surface Parts in 3D Rolling Process

2014 ◽  
Vol 687-691 ◽  
pp. 3-6
Author(s):  
Da Ming Wang ◽  
Ming Zhe Li ◽  
Zhong Yi Cai
Keyword(s):  
Sheet Metal ◽  
Spherical Surface ◽  
Three Dimensional ◽  
Rolling Process ◽  
Experimental Results ◽  
Transition Zones ◽  
Spherical Surfaces ◽  
Sheet Width ◽  
Forming Precision ◽  
Roll Gap

3D rolling is a novel technology for three-dimensional surface parts. In this process, by controlling the gap between the upper and lower forming rolls, the sheet metal is non-uniformly thinned in thickness direction, and the longitudinal elongation of the sheet metal is different along the transverse direction, which makes the sheet metal generate three-dimensional deformation. In this paper, the transition zones of spherical surface parts in 3D rolling process are investigated. Spherical surface parts with the same widths but different lengths are simulated in condition of the same roll gap, and their experimental results are presented. The forming precision of forming parts and the causes of transition zones in the head and tail regions are analyzed through simulated results. The simulated and experimental results show that the lengths of transition zones of spherical surfaces in the head and tail regions are fixed values in condition of the same sheet width and roll gap.

scholarly journals Verification of normal distribution of welding distortions

2019 ◽  
Vol 91 (3) ◽  
Author(s):  
Damian Grzesiak ◽  
Jarosław Plichta
Keyword(s):  
Statistical Analysis ◽  
Standard Deviation ◽  
Normal Distribution ◽  
Sheet Metal ◽  
Welding Process ◽  
Experiment Planning ◽  
Geometrical Parameters ◽  
Butt Welds ◽  
Planning Methods ◽  
Smirnov Test

The aim of this paper is to answer the question of the distribution of welding distortions. The MIG method was used to make 31 butt welds of 0H18N9 sheet metal, of 6 mm thickness and dimensions 150x350 mm. All joints are made with constant parameters of the welding process. Statistical analysis of the distribution and Kolomogorov-Smirnov test were used in this paper. On the grounds of the analysis it was proved that the distribution of welding deformations is a normal distribution. This justifies the use of experiment planning methods and the use of average values. The relatively high value of the standard deviation makes it necessary to take into account the geometrical parameters of the joint.

scholarly journals Сlinical, immunological and morphological features in different types of autoimmune hepatitis

2020 ◽  
Vol 92 (2) ◽  
pp. 43-47
Author(s):  
Yu. G. Sandler ◽  
K. G. Saliev ◽  
S. N. Backih ◽  
S. G. Khomeriki ◽  
T. Yu. Khaymenova ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Statistical Analysis ◽  
Autoimmune Hepatitis ◽  
Clinical Laboratory ◽  
Clinical Manifestations ◽  
Morphological Characteristics ◽  
Morphological Features ◽  
Assessment System ◽  
Associated Diseases ◽  
Number Of Patients

Due to the absence of the pathognomonic diagnostic criteria and to the diversity of clinical, serological and morphological manifestations, the diagnostic of the autoimmune hepatitis (AIH) remains to be a difficult task, which might lead to the delay of the timely beginning of the immunosuppressive therapy (IST), which in turn affects the disease outcomes. Aim.To studying the clinical, biochemical, immunological and morphological markers in patients with seronegative (SN) and seropositive (SP) AIH and the qualities of their response to the IST. Materials and methods.This retrospective cohort study included 82 AIH patients over the course of the years 20142019. All patients were selected in accordance with the criteria of the simplified assessment system of the IAIHG. Clinical, laboratorial and morphological characteristics of the AIH were analyzed. Therapy response was evaluated by the level of the ALT and IgG in 612 months after the start of the IST. The study material underwent statistical analysis using methods of parametrical and nonparametrical analysis. Statistical analysis was performed in the Statistica 13.3 (developed by StatSoft Inc., USA). Results.67/82 (81.70%) of the patients studied were women, median age of 54 years old [38; 70]. Patients with the diagnosis of the possible AIH according to the IAIHG made 85.4% (70 people). Almost everyone 96% (79/82) had morphological features of the interface-hepatitis with the lymphocytic/plasmocytic infiltration; emperipolesis was discovered in 63% of patients (49/82), hepatocellular rosette in 23% (19/82). Patients with SN AIH comprised 36.5% (30/82), with SP 63.4% (52/82). Comparative analysis demonstrated that the clinical profile in patients with SN and SP AIH is the same, while the incidence of immuno-associated diseases is significantly higher in the group of seronegative AIH. The morphological profile in the two AIH groups is identical in both typical and atypical manifestations. The number of responders to IST was 63% (19/30) SN AIH vs 67% SP AIH (35/52), did not differ significantly (p=0.529).However, that the number of patients with liver cirrhosis in the SN AIH group was twice as big as the ones with SP: 37% vs 17% (p=0.089). Conclusions.A comparative analysis of clinical, laboratory, morphological and clinical manifestations in the SN and SP AIH groups did not detected statistically significant significant differences, which may indicate that SN and SP AIH are the faces of one disease. It is possible that AB cannot be identified within the known spectrum of antibodies, or antibodies have slow expression, or are suppressed by the immune system. In any case, suspicions of AIH, in the absence of antibodies, it is recommended that liver biopsy be performed for the timely diagnosis of AIH and IST. Сirrhosis was more often diagnosed in the group SN AIH, which may be due to a later diagnosis, and therefore to untimely IST. The found frequent association of SN AIH with other immune-associated diseases requires a carefully study of this problem. The variety of clinical manifestations of AIH requires further study, the identification of clinical phenotypes with certain feature. This can help in the future to timely identify potentially problematic patients and predict a response to IST.

scholarly journals Insights into Exploration and Exploitation Power of Optimization Algorithm Using DSCTool

Mathematics ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1474
Author(s):  
Peter Korošec ◽  
Tome Eftimov
Keyword(s):  
Statistical Analysis ◽  
Web Service ◽  
Optimization Algorithm ◽  
Optimization Algorithms ◽  
Search Space ◽  
Exploration And Exploitation ◽  
Learning Tool ◽  
Additional Information ◽  
E Learning ◽  
Single Objective

When making statistical analysis of single-objective optimization algorithms’ performance, researchers usually estimate it according to the obtained optimization results in the form of minimal/maximal values. Though this is a good indicator about the performance of the algorithm, it does not provide any information about the reasons why it happens. One possibility to get additional information about the performance of the algorithms is to study their exploration and exploitation abilities. In this paper, we present an easy-to-use step by step pipeline that can be used for performing exploration and exploitation analysis of single-objective optimization algorithms. The pipeline is based on a web-service-based e-Learning tool called DSCTool, which can be used for making statistical analysis not only with regard to the obtained solution values but also with regard to the distribution of the solutions in the search space. Its usage does not require any special statistic knowledge from the user. The gained knowledge from such analysis can be used to better understand algorithm’s performance when compared to other algorithms or while performing hyperparameter tuning.

Opera latina: le nouveau site Internet du LASLA

2007 ◽  
Vol 9 (3) ◽  
Author(s):  
Joseph Denooz
Keyword(s):  
Statistical Analysis ◽  
Software Package ◽  
Data Bank ◽  
Complete Data ◽  
Morphological Features ◽  
The Internet ◽  
Specific Language ◽  
The University ◽  
Site Internet

AbstractSince 1961 the Laboratory for statistical analysis of ancient languages (LASLA) at the University of Liège has recorded a high number of ancient Latin texts in a computer format. For each of the approximately 1,800,000 words of the corpus lexicological, morphological and syntactical information has been entered. The complete data bank is now accessible through the Internet: an inquiry software package makes it possible for any researcher to look up all occurrences of a specific language feature either in the whole corpus or in the works of a given writer. Research can be done either on a lexis item, or on a type of subordination, or again on the basis of morphological features. The system, which still has to be further developed, is available for anyone who files a request.

THE EFFECTS OF ACCUMULATIVE ROLL BONDING PROCESS ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF IF STEEL

2008 ◽  
Vol 22 (18n19) ◽  
pp. 2866-2873 ◽  
Author(s):  
SAEED TAMIMI ◽  
MOSTAFA KETABCHI ◽  
NADER PARVIN
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Accumulative Roll Bonding ◽  
Low Carbon Steel ◽  
Rolling Process ◽  
Low Carbon ◽  
Roll Bonding ◽  
Rolling Pass ◽  
Steel Strips ◽  
Wire Brushing

This work aims to investigate whether accumulative roll bonding (ARB) is an effective grain refinement technique for ultra-low-carbon steel strips containing 0.004% C. For this purpose, a number of ARB processes were performed at 500 °C, with 50% reduction in area of each rolling pass. It was found that both the ultimate grain size achieved, as well as the degree of bonding, depend on number of rolling pass and reduction of area as a whole. The mean grain size was obtained using AFM was about 130nm. The mechanical properties after rolling and cooling were obtained. Also, the fracture surfaces were studied by Scanning Electron Microscopy (SEM). It was concluded that metal's tensile strengths increased by 334% while the ductility dropped from a prerolled value of 50.5% to 2.6%. Effect of wire brushing on samples observed too. It increased on the wire brushed sheet for 7 HV. The rolling process was stopped when cracking of the edges became pronounced.

Combination of Finite-Element and Semi-Analytical Models for Sheet Metal Leveling Simulation

2011 ◽  
Vol 473 ◽  
pp. 182-189
Author(s):  
Amine Amor ◽  
Mohamed Rachik ◽  
Hédi Sfar
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Element Model ◽  
Rolling Process ◽  
Process Efficiency ◽  
Analytical Models ◽  
Initial Shape ◽  
Residual Curvature ◽  
Matlab Programming ◽  
Alternating Bending

Coiled sheet metal often exhibits shape defects that result from the rolling process or the coiling operation. To meet the quality requirement, these defects need to be removed using leveling and straightening. The process efficiency strongly depends on several parameters like the machine design, the rollers penetration and the sheet metal. Consequently, the leveling process is very sensitive and it is difficult to find the appropriate setting using trial and error procedure. In this context, numerical simulation can be very helpful. The aim of our work is to predict the residual curvature of the sheet knowing its initial shape and the leveling process settings. The simulation is carried out in two steps to integrate the global and the local behavior of the strip along the leveling process. In the first step, a 2D finite element model is used to predict the sheet metal deformations under the rollers action. In this first step the strip curvatures along the leveling machine are predicted. The so obtained results are then used to simulate the alternating bending and the spring back of the strip with the help of a semi-analytical model using the MATLAB programming environment. To validate the proposed approach, leveling tests were carried out on a 2.5 mm thickness sheet of DX51 steel and the measured residual curvatures are compared with the predictions. These comparisons show that satisfactory predictions can be obtained with good computational efficiency.

scholarly journals Application of Machine Learning to Bending Processes and Material Identification

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1418
Author(s):  
Daniel J. Cruz ◽  
Manuel R. Barbosa ◽  
Abel D. Santos ◽  
Sara S. Miranda ◽  
Rui L. Amaral
Keyword(s):  
Machine Learning ◽  
Sheet Metal ◽  
Bending Test ◽  
Model Parameters ◽  
Learning Approaches ◽  
Additional Information ◽  
The Many ◽  
And Control ◽  
Force Displacement ◽  
Springback Angle

The increasing availability of data, which becomes a continually increasing trend in multiple fields of application, has given machine learning approaches a renewed interest in recent years. Accordingly, manufacturing processes and sheet metal forming follow such directions, having in mind the efficiency and control of the many parameters involved, in processing and material characterization. In this article, two applications are considered to explore the capability of machine learning modeling through shallow artificial neural networks (ANN). One consists of developing an ANN to identify the constitutive model parameters of a material using the force–displacement curves obtained with a standard bending test. The second one concentrates on the springback problem in sheet metal press-brake air bending, with the objective of predicting the punch displacement required to attain a desired bending angle, including additional information of the springback angle. The required data for designing the ANN solutions are collected from numerical simulation using finite element methodology (FEM), which in turn was validated by experiments.

scholarly journals Formability of Bimodal Steel Strips Subjected to Heavy-reduction Controlled-rolling Process

2019 ◽  
Vol 105 (2) ◽  
pp. 190-196
Author(s):  
Hyung-Won Park ◽  
Kei Shimojima ◽  
Sumio Sugiyama ◽  
Jun Yanagimoto
Keyword(s):  
Rolling Process ◽  
Controlled Rolling ◽  
Steel Strips

scholarly journals The Effect of Jury Experience on Jury Verdicts

1982 ◽  
Vol 2 ◽  
pp. 62-73
Author(s):  
Charles Chastain
Keyword(s):  
Statistical Analysis ◽  
Statistical Data ◽  
Additional Analysis ◽  
Defense Attorneys ◽  
Jury Verdicts ◽  
Jury Trials ◽  
The Relationship

This study considers the hypothesis that juries with more experience are more likely to convict a defendant than less experienced juries are. The theory, which has wide support among prosecutors and defense attorneys, is tested by taking all the jury trials in the Sixth Judicial District in Arkansas for the years 1978 and 1979, identifying juries with greater experience and those with less experience during those two years, and using statistical analysis to determine the strength of the relationship. The results indicate that the theory is not statistically supported. An additional analysis was completed to determine if a relationship exists between jury experience and severity of sentence. This theory also could not be supported by the statistical data. The conclusion is reached that no relationship exists between jury experience and jury verdicts, but it is acknowledged that manipulation of the cases, which come before the various juries may skew the results of the statistical analysis.

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