Sökning: "defect detection"

Visar resultat 1 - 5 av 61 avhandlingar innehållade orden defect detection.

1. 1. In-situ monitoring of laser powder bed fusion applied to defect detection

   Författare :Claudia de Andrade Schwerz; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; defect detection; productivity; nickel-based superalloy; process monitoring; pores; powder bed fusion; spatter; defect mitigation; mechanical properties; lack of fusion; melt pool; Additive manufacturing;

   Sammanfattning : Additive manufacturing technologies, particularly laser powder bed fusion (LPBF), have received much attention recently due to their numerous advantages over conventional manufacturing methods. However, the use of LPBF is still quite restricted, mainly due to two factors: its typically low productivity, which makes the technology less competitive in applications with moderate to high production volumes, and its limited reliability, particularly relevant for applications where high performance is required from the materials. LÄS MER

3. 2. An Algorithmic Framework for Intelligent Concrete Structural Defects Detection and Classification

   Författare :Ali Mirzazade; Björn Täljsten; Cosmin Popescu; Thomas Blanksvärd; Diogo Rodrigo Ferreira Ribeiro; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Civil Engineering Structures; defect detection; Structural Health Assessment; Bridge Inspection; Computer Vision; Point-Cloud Generation; Severity Assessment; Machine Learning Regression; Bridge 3D Modeling; Unmanned Inspections; Byggkonstruktion; Structural Engineering;

   Sammanfattning : The primary objective of inspecting concrete civil structures is to gather information concerning the deterioration of concrete elements, including issues like concrete cover cracking, delamination, or corrosion. Typically, this data is documented through field inspection notes, hand-drawn sketches, and photographs. LÄS MER

4. 3. Ultrasonic NDT in Defect Detection - Mathematical modelling

   Författare :Håkan Wirdelius; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; crack; null field approach; transducers; optimisation; ultrasonics; elastic waves; nondestructive testing; T matrix method; inverse problem;

   Sammanfattning : This thesis is concerned with the mathematical modelling of the ultrasonic nondestructive testing situation. The first part of the thesis treats a simplified model of an ultrasonic transducer and its implementation into a T-matrix method-based solution to a crack scattering problem. LÄS MER

5. 4. Early detection of critical congenital heart defects in Sweden - with a focus on coarctation of the aorta

   Författare :Katarina Lannering; Göteborgs universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; critical congenital heart defect; coarctation of the aorta; newborn; early detection; screening;

   Sammanfattning : Introduction: Despite the implementation of prenatal and neonatal screening, newborn infants with critical congenital heart defects (CCHD) remain at risk of being discharged undiagnosed, particularly newborns with coarcation of the aorta (CoA). Recent studies have suggested that perfusion index (PI) may potentially identify additional cases of CoA. LÄS MER

7. 5. Optimal Detectors for Transient Signal Families and Nonlinear Sensors : Derivations and Applications

   Författare :Daniel Asraf; Mats Gustafsson; Anders Grennberg; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Signalbehandling; optimal detection; transient signals; noncoherent detection; unknown arrival time; ultrasonic nondestructive testing; nonlinear sensor; stochastic resonance; Signalbehandling; Signal processing; Signalbehandling; Signal Processing; signalbehandling;

   Sammanfattning : This thesis is concerned with detection of transient signal families and detectors in nonlinear static sensor systems. The detection problems are treated within the framework of likelihood ratio based binary hypothesis testing. LÄS MER