NON-INVASIVE ANALYSIS AND VISUALIZATION OF OBJECTS FROM FSW AlSi9Mg/2017A ALUMINUM ALLOY JOINTS

Friction stir welding (FSW) technology allows for the welding of materials that differ in their chemical compositions, microstructures, and properties. When selecting the parameters, it is necessary to analyze the structure of a weld and eliminate the defects. The use of X-ray microtomography creates the possibility of precise imaging of a joint structure – especially when it contains defects (voids). The tests were carried out on an FSW joint made with both 2017A and AlSi9Mg aluminum alloys. The macrostructure was cross-sectional, and a defect was found in the middle part of the joint and on the advancing side. We used a conventional method of observation light microscopy. Then, an analysis was performed using X-ray microtomography, which revealed the shape of the defect in 3D. Individual cross-sections were extracted, which enabled us to measure the geometric quantities. A dependence was found for the shape of the defect on the welding parameters and the variability of its construction. The usefulness of this advanced material imaging technology for the analysis of FSW welds has been confirmed

X-ray microtomography analysis of the aluminum alloy composite reinforced by SiC after Friction Stir Processing

Despite many years of using friction stir processing (FSP), there are many unexplained aspects concerning the processes which appear during FSP: determining the direction of flow and mixing of the materials and the degree of mixing and microstructure fragmentation in specific areas. This paper presents the impact of FSP on the micro- and macrostructure of the composite with hypo-eutectic Si matrix reinforced by SiC particles. The analysis of the structure of the processed area in FSP in the relation to the microstructure of the base material has been made using x-ray microtomography. The results of these studies have been juxtaposed with studies using microscopic methods (light microscopy and SEM). The microtomography images revealed an additional separation on the advancing side and the weld nugget, where on the basis of a 3D reconstruction a layer microstructure on the direction of linear movement of the tool has been demonstrated. The analyses have revealed a limited flow of the material above the weld nugget. The main advantages of the research method applied were the possibility to show the invisible or barely visible elements of the microstructure using standard test methods and the ability to analyze the microstructure changes uninterruptedly in different directions in the volume of the material

FEATURES OF 2017A AND AlSi9Mg ALUMINUM ALLOYS FRICTION STIR WELDED WITH ROOT-SIDE HEATING

Aluminum alloys 2017A and AlSi9Mg (hypo-eutectic silumin) were friction stir welded with a relatively high linear velocity (over 1 m/min) and use of an additional heat source from the root side of the weld. Macrostructure investigation (with high-resolution images) showed no effect of heating on weld quality. The welding process caused significant fragmentation of the secondary phases in the AlSi9Mg alloy. Furthermore, it was proven that the material above the weld nugget was not mixed and contained micro-defects that were not caused by welding. Also, it contained cavities on the boundaries between Si-particles and the matrix. Based on hardness distribution, a slight strengthening of the cast alloy was observed at the bottom and middle parts of the weld. However, the hardness of the 2017A alloy initially decreased and then increased due to natural aging. This means that the FSW process produced a metastable state in the alloy

The Object Segmentation from the Microstructure of a FSW Dissimilar Weld

Friction stir welding (FSW) is an environmentally friendly, solid-state welding technique. In this research work, we analyze the microstructure of a new type of FSW weld applying a two- stage framework based on image processing algorithms containing a segmentation step and microstructure analysis of objects occurring in different layers. A dual-speed tool as used to prepare the tested weld. In this paper, we present the segmentation method for recognizing areas containing particles forming bands in the microstructure of a dissimilar weld of aluminum alloys made by FSW technology. A digital analysis was performed on the images obtained using an Olympus GX51 light microscope. The image analysis process consisted of basic segmentation methods in conjunction with domain knowledge and object detection located in different layers of a weld using morphological operations and point transformations. These methods proved to be effective in the analysis of the microstructure images corrupted by noise. The segmentation parts as well as single objects were separated enough to analyze the distribution on different layers of the specimen and the variability of shape and size of the underlying microstructures, which was not possible without computer vision support

Influence of omalizumab therapy on airway remodeling assessed with high-resolution computed tomography (HRCT) in severe allergic asthma patients

Introduction: Airway remodeling is an important factor in persistent obstruction in severe asthma. High resolution computed tomography (HRCT) is an effective method of detecting changes in airway structure. Our aim was to use HRCT to assess changes in airway remodeling in patients with severe allergic asthma who are treated with omalizumab. Material and methods: In 12 patients with severe allergic asthma, HRCT was performed before and after treatment with omalizumab. In selected bronchi airways, parameters were calculated: bronchial wall area (BA), also corrected for body surface area (BSA); percentage of wall area (WA%); and the ratio of luminal area to total bronchial area (Ai/Ao). Clinical response to treatment was assessed using an asthma control questionnaire (ACQ), asthma quality of life questionnaire (AQLQ), and number of exacerbations per year. Assessment included spirometry and blood eosinophilia. Results: Treatment resulted in significant improvement in ACQ (p = 0.035) and AQLQ (p = 0.001). We observed significant reduction in exacerbations per year (p = 0.002) and reduction of daily systemic steroid dose (p = 0.032). FEV1 and peripheral blood eospinophilia did not change (p = 0.846 and p = 0.221). Airway dimensions (Ai/Ao) of particular bronchi were consistent with the mean of the parameters calculated for all bronchi measured. Although we observed a significant decrease in WA (p = 0.002) and WA/BSA (p = 0.002), WA% and Ai/Ao did not improve (p = 0.39 and p = 0.49). We found no correlations between changes in airways and changes in spirometry or clinical parameters. Conclusion: Despite clinical effectiveness of omalizumab, its effect on airway remodeling may be limited

Influence of omalizumab therapy on airway remodeling assessed with high-resolution computed tomography (HRCT) in severe allergic asthma patients

Introduction: Airway remodeling is an important factor in persistent obstruction in severe asthma. High resolution computed tomography (HRCT) is an effective method of detecting changes in airway structure. Our aim was to use HRCT to assess changes in airway remodeling in patients with severe allergic asthma who are treated with omalizumab. Material and methods: In 12 patients with severe allergic asthma, HRCT was performed before and after treatment with omalizumab. In selected bronchial airways, parameters were calculated: bronchial wall area (BA), also corrected for body surface area (BSA); percentage of wall area (WA%); and the ratio of luminal area to total bronchial area (Ai/Ao). Clinical response to treatment was assessed using an asthma control questionnaire (ACQ), asthma quality of life questionnaire (AQLQ), and number of exacerbations per year. Assessment included spirometry and blood eosinophilia. Results: Treatment resulted in significant improvement in ACQ (p = 0.035) and AQLQ (p = 0.001). We observed significant reduction in exacerbations per year (p = 0.002) and reduction of daily systemic steroid dose (p = 0.032). FEV₁ and peripheral blood eospinophilia did not change (p = 0.846 and p = 0.221). Airway dimensions (Ai/Ao) of particular bronchi were consistent with the mean of the parameters calculated for all bronchi measured. Although we observed a significant decrease in WA (p = 0.002) and WA/BSA (p = 0.002), WA% and Ai/Ao did not improve (p = 0.39 and p = 0.49). We found no correlations between changes in airways and changes in spirometry or clinical parameters. Conclusion: Despite clinical effectiveness of omalizumab, its effect on airway remodeling may be limited

Wpływ leczenia omalizumabem na remodeling dróg oddechowych oceniony za pomocą tomografii komputerowej wysokiej rozdzielczości (TKWR) u chorych na ciężką astmę alergiczną

WSTĘP: Remodeling dróg oddechowych jest istotną składową utrwalonej obturacji w ciężkiej astmie. Tomografia komputerowa wysokiej rozdzielczości (TKWR) to skuteczna metoda wykrywania zmian w strukturze dróg oddechowych. Celem pracy jest wykorzystanie TKWR do oceny zmian w remodelingu dróg oddechowych u pacjentów z ciężką astmą alergiczną leczonych biologicznie omalizumabem. MATERIAŁ I METODY: U 12 pacjentów z ciężką astmą alergiczną, wykonano TKWR klatki piersiowej przed i po leczeniu omalizumabem. W wybranych oskrzelach obliczono następujące parametry: pole powierzchni ściany oskrzela (BA, bronchial wall area), również skorygowane o powierzchnię ciała (BSA, body surface area); procent powierzchni ściany oskrzela (WA%, wall area); i stosunek powierzchni światła do całkowitej powierzchni oskrzela (Ai / Ao). Odpowiedź kliniczną na leczenie oceniano za pomocą kwestionariusza kontroli astmy (ACQ, asthma control questionnaire), kwestionariusza jakości życia w astmie (AQLQ, asthma quality of life questionnaire) i liczby zaostrzeń w ciągu roku. Ocena obejmowała również spirometrię i eozynofilię krwi obwodowej. WYNIKI: Leczenie spowodowało istotną poprawę ACQ (p = 0,035) i AQLQ (p = 0,001). Zaobserwowano istotną redukcję zaostrzeń w ciągu roku (p = 0,002) i zmniejszenie dziennej dawki steroidu sytemowego (p = 0,032). Natężona objętość wydechowa pierwszosekundowa (FEV1, forced expiratory volume in 1 second) i eozynofilia krwi obwodowej nie uległy zmianie (p = 0,846 i p = 0,221). Wymiary dróg oddechowych (Ai/Ao) poszczególnych oskrzeli były zgodne ze średnią parametrów obliczonych dla wszystkich zmierzonych oskrzeli. Chociaż zaobserwowano znaczny spadek WA (p = 0,002) i WA/BSA (p = 0,002), WA% i Ai/ /Ao nie uległy poprawie (p = 0,39 i p = 0,49). Nie stwierdzono korelacji między zmianami w drogach oddechowych a zmianami w spirometrii lub parametrach klinicznych. WNIOSEK: Pomimo skuteczności klinicznej omalizumabu, jego wpływ na remodeling dróg oddechowych może być ograniczony.WSTĘP: Remodeling dróg oddechowych jest istotną składową utrwalonej obturacji w ciężkiej astmie. Tomografia komputerowa wysokiej rozdzielczości (TKWR) to skuteczna metoda wykrywania zmian w strukturze dróg oddechowych. Celem pracy jest wykorzystanie TKWR do oceny zmian w remodelingu dróg oddechowych u pacjentów z ciężką astmą alergiczną leczonych biologicznie omalizumabem. MATERIAŁ I METODY: U 12 pacjentów z ciężką astmą alergiczną, wykonano TKWR klatki piersiowej przed i po leczeniu omalizumabem. W wybranych oskrzelach obliczono następujące parametry: pole powierzchni ściany oskrzela (BA, bronchial wall area), również skorygowane o powierzchnię ciała (BSA, body surface area); procent powierzchni ściany oskrzela (WA%, wall area); i stosunek powierzchni światła do całkowitej powierzchni oskrzela (Ai / Ao). Odpowiedź kliniczną na leczenie oceniano za pomocą kwestionariusza kontroli astmy (ACQ, asthma control questionnaire), kwestionariusza jakości życia w astmie (AQLQ, asthma quality of life questionnaire) i liczby zaostrzeń w ciągu roku. Ocena obejmowała również spirometrię i eozynofilię krwi obwodowej. WYNIKI: Leczenie spowodowało istotną poprawę ACQ (p = 0,035) i AQLQ (p = 0,001). Zaobserwowano istotną redukcję zaostrzeń w ciągu roku (p = 0,002) i zmniejszenie dziennej dawki steroidu sytemowego (p = 0,032). Natężona objętość wydechowa pierwszosekundowa (FEV1, forced expiratory volume in 1 second) i eozynofilia krwi obwodowej nie uległy zmianie (p = 0,846 i p = 0,221). Wymiary dróg oddechowych (Ai/Ao) poszczególnych oskrzeli były zgodne ze średnią parametrów obliczonych dla wszystkich zmierzonych oskrzeli. Chociaż zaobserwowano znaczny spadek WA (p = 0,002) i WA/BSA (p = 0,002), WA% i Ai/ /Ao nie uległy poprawie (p = 0,39 i p = 0,49). Nie stwierdzono korelacji między zmianami w drogach oddechowych a zmianami w spirometrii lub parametrach klinicznych. WNIOSEK: Pomimo skuteczności klinicznej omalizumabu, jego wpływ na remodeling dróg oddechowych może być ograniczony