Aneta Gądek-Moszczak

The Smooth Bootstrap Approach to the Distribution of a Shape in the Ferritic Stainless Steel AISI 434L Powders

The ferritic-austenitic stainless steel was obtained by sintering the mixture of ferritic stainless steel AISI 434L powders with different amount of additions: Mn, Ni and Si. The structure of obtained sintered samples was investigated by computer image analysis methods. In porous materials the character of the pore structure strongly effects on its mechanical properties. Accurate information about pores shape is important information for technological process and quality control of produced materials as well. The images of the porous microstructure were analyzed using ADCIS Aphelion analytical software. Analyzed pores have complex and irregular shapes and thus authors decided to appoint different shape factors to obtain its proper quantitative description. Data obtained from image analysis process were statistically analyzed. Authors used a special resampling approach known as smooth bootstrapping to smoothing cumulative empirical distributions. The results obtained during resampling procedure have been compared with raw data from verification set and guidelines for the application of the proposed approach have been formulated. The validity of the proposed approach was positively verified and it significantly improved quality of the results. The smoothing and imputing of data allow to avoid numerical artifacts that may arise during the classical statistical calculations on irregular data originated from image analysis obtained from sintered samples. Efficient, reliable and relatively fast method for accessing the distribution of any others quantitative parameters describing microstructure of the materials is very interesting proposal for wide spectrum of application.

Modeling of Errors Counting System for PCB Soldered in the Wave Soldering Technology

PartnerTech provides printed circuit board (PCB) assembly on request. Wired elements are assembled in through-hole technology and soldered on the wave soldering machine. The PCB with inserted elements is passed across the pumped wave of melted solder. Typically this process is accompanied by some class of defects like cracks, cavities, wrong solder thickness and poor conductor. In PartnerTech Ltd. another type of defects was observed: dispersion of small droplets of solder around holes. Quality assurance department plans to optimize the process in order to reduce the number of defects. In the first stage, it was necessary to develop a methodology for counting defects. This paper presents experimental design and analysis related to this project.

The Impact of Detection Methods on the Results of Quantitative Analysis of the Surface Layer WC-CoAl2O3

In the article authors presented digital measurement problem of the object on the 3D images of the microstructures. As a research material were used the micro tomography image of the probe C45 steel with WC-Co-Al2O3 surface layer. Due to relatively low contrast between the surface layer and the root material, and lack of sharp edges, some of the methods for automatic threshold indication may give biased results. Following the initial selection of the many methods of automatic binarization two of them and interactive method was selected to carry out comparative studies. The analysis included assessment of the layer thickness, number of detected objects and total volume of all detected objects.

The Bootstrap Approach to the Comparison of Two Methods Applied to the Evaluation of the Growth Index in the Analysis of the Digital X-ray Image of a Bone Regenerate

The bone elongation by Ilizarov method is the important way of treatment of physical disability. During the elongation is necessary to control the accumulation of a regenerate and indicate the moment when fixator should be removed. The control is performed by observing the X-ray images and evaluation of the Regenerate Development coefficient. The automated image analysis is used to ensure the objectivity and reproducibility of the measurement. The authors have developed a new method for evaluating coefficient reflecting the specific treatment regenerate parts of an image associated with intramedullary nail. To assess the equivalence of the method with respect to the current, the bootstrap method was applied to sample of 23 X ray images. The bootstrap method provided the simulated distribution of the difference between the index obtained from the new method and the index obtained from the previous one.

Kinect application as virtual patient assistant on the example of the shoulder pain exercises

In the paper authors reports the first results of the working out application that would assistance and controls the patients during the rehabilitation exercise at home, what would effects in faster and more effective rehabilitation results. Proposed by authors conception of the application is programmed on the Kinect SDK environment and applies this simple and popular entertainment device to support rehabilitation process what ensure low costs of the implementation.

Application the 3D Image Analysis Techniques for Assessment the Quality of Material Surface Layer before and after Laser Treatment

In the paper authors presented the application of specific method of assessment chosen properties of coating layer, that give additional information strictly connected with its tribology properties. Nanotomography techniques and 3D image processing gives quantitative and qualitative information about the testing sample, with no negative effects on the exanimating layer. Two samples, one with and one without the laser treatment were tested, measured and obtained results presented and discussed. Those preliminary research shown that proposed method can be recommended to application as a supplementary test of the properties coating layers and for verification of technological process parameters on the stage of working out the production process.

Description of 3D Microstructure of the Composites with Polypropylene (PP) Matrix and Tuf Particles Fillers

The main goal of the study was working out the method of qualitative and quantitative analysis of the microstructure on 3D images of the polypropylene composites with Tuf (type of rock consisting volcanic ash) particles. Three types of composite were analyzed: with 10, 15 and 25% of Tuf. The standard morphological parameters were indicated that describes size, shape, and distribution of Tuf particles in the matrix. The morphological characterization of examined microstructure was compared with mechanical properties. The optimal from the point of mechanical properties composition of this composite were proposed.

The parametric RSM model with higher order terms for the meat tumbler machine process

Typical design of experiments (DoE) approach to the response surface problem applies the polynomials with at most the second order terms. It is correct due to the Taylor’s theorem when the variability of input variables is sufficiently small. Unfortunately, the variability bound of a designed experiment is planned with high uncertainty about the investigated object’s behavior. If the response of the object has a large curvature then model quality indicators (residuals normality, lack of fit, significance of terms) appear to be unacceptable. In such a case, polynomial terms with the order higher than second should be applied. The paper describes the RSM model with the fourth order terms identified for relationship between settings of a meat tumbler machine (input variables) and the Warner-Bratzler shear force (output variable).

The Estimation of Accuracy for the Neural Network Approximation in the Case of Sintered Metal Properties

The spatial structure of sintered metal powders is described by many qualitative and quantitative micro-geometrical properties. The statistical approach based on univariate and multivariate distributions is very useful for consistent and objective description of such structures. It provides information appropriate for a whole population of sinters, not only particular specimen. Empirical distributions of quantitative properties obtained from the image analysis are very irregular and for this reason inconvenient for further numerical simulations. The smoothing of these distributions is required for data conditioning and preprocessing however, the use of simple regression techniques is limited due to the strict lower and upper bound of cumulative distribution function. Authors propose to use a multilayer perceptron as a non-parametric regression model because of its the well-known smoothing properties. The technical application of such model requires additionally providing of the confidence band or any equivalent measure of uncertainty. The highly non-linear structure of the neural network model makes not possible to use typical linear techniques to estimate variance. Additionally, the simple confidence band estimation leads to non-physical values of the cumulative distribution function: lower than 0 or greater than 1. Authors propose to avoid such difficulties by two methods. Firstly, the lower and upper bound limitation are satisfied by the logit transformation which projects the range [0, 1] into unlimited real range. Secondly, the variance of the neural network model is estimated by jackknife estimator. The article presents such approach with preliminary attempt to an automated data processing by ADCIS Aphelion image analysis software and STATSOFT Statistica data analysis software. The almost full automation of the process is required by materials science engineers due to the lack of the sufficient data processing knowledge and skills. Both software systems provide suitable embedded programming environments: C# for Aphelion and Visual Basic for Statistica. The proposed approach has been tested on the example of pore size distribution in sintered stainless steel AISI 434L.

Evaluation of the State for the Material of the Live Steam Superheater Pipe Coils of V Degree

The main aim of the undertaken research was to evaluate the state of the material of V degree live steam superheater pipe coils made of 10CrMo9-10 (10H2M) chromium-molybdenum steel as well as to determine their usability for further operation. The pipe coils came from a steam boiler working at a power plant. The scope of the research included: a literature analysis of the issue, an elaboration of the research plan, cutting and preparing the test samples, microstructural tests with the use of a light microscope, microstructural tests performed by means of a scanning electron microscope and conclusion drawing on the basis of the performed tests and the literature review. The work presents the steels of which the mentioned elements were made as well as analyzes their working conditions. It describes the most often observed causes of pipe coil damage and presents techniques of controlling the proper efficiency and usability of these elements for further operation.