OBJECTIVES: The objectives of this study was to determine the differences in failure load between cemented and fused machined veneers to zirconia while observing the effects of real time aging on failure load between cemented and fused machined veneers to zirconia. The study was to examine the differences in aging and fatigue resistance amongst a machined glass-ceramic veneer and a machined feldspathic porcelain veneer. MATERIALS AND METHODS: VITA In Ceram YZ zirconia blocks were used as a substructure framework for the three unit fixed partial denture. The veneering material was either milled IPS e.max CAD (glass-ceramic) or milled VITABLOCS Triluxe Forte (feldspathic porcelain). The types of linking material between the substructures and veneering material were either fusing or cementation. Observations were compared between aged and non-aged specimens divided into two main groups; (a) non-aged group (b) aged for three years at room temperature. Each group has two subgroups; fused and cemented which are further divided into static and cyclic fatigue at 20K, 60K and 80K. Specimens were subjected to load to failure test using universal test machine. 40% of failure load was calculated for the cyclic fatigue subgroups. In order to examine the difference in failure load between the static and fatigued specimens, the Tukey-Kramer HSD test was used to analyze the data. RESULTS AND CONCLUSIONS: The VITABLOCS Triluxe Forte (feldspathic porcelain) fused to YZ zirconia showed significantly lower failure load values compared to all the other groups (p˂0.05). The non-aged VITABLOCS Triluxe Forte cemented to YZ zirconia (static and cyclic) showed significantly higher load to failure than the aged cemented Triluxe fatigued groups (p˂0.05). There is no significant difference in failure load between IPS e.max CAD fused and IPS e.max CAD cemented to YZ zirconia framework (p˃0.05). The aged IPS e.max CAD fatigued (20K, 60K and 80K cycles) cemented to YZ zirconia showed lower significant difference in failure load among all the other IPS e.max groups. (p˂0.05).

The development of information technology, IT, has resultedin big changes in the last decade. Personal computers, mobilephones andaccess to the Internet have been widely spread, andthe development of software and systems has contributed to newways of working and new possibilities for communication. Inmany industries, the use of IT has lead to increasedeffectiveness and productivity. In the construction industrymuch effort has been made to improve processes with the help ofIT, but the industry has not achieved increased productivity tothe same extent as others. The aim of this research is tocreate a better understanding of how different parts of theSwedish construction industry make use of IT and how theyjustify their investments in IT. The work has been carried outusing surveys. Postal questionnaires as well as interviews havebeen used. The research project started with the design anddevelopment of a questionnaire, which has been used twice inSweden. The same questionnaire has also been used in Denmarkand Finland on the same occasions. The results of the postalsurveys have, to some extent, been compared with similarsurveys regarding other industries in Sweden, as well as theconstruction industries in other countries. The findings fromthe postal surveys have also been used as a basis for aninterview study with twelve companies in the Swedishconstruction industry, with the purpose of explaining theexisting level of IT use. The conclusions that were reachedwere that the access to IT is widespread in the industry, andthat the use is concentrated in the areas of: administration,communication and design. There is a lack of use and investmentin advanced systems such as product models, virtual reality andelectronic trading. The contractors use IT to the least extentin the industry. The reasons for adopting and using IT, or notdoing so, have been divided into five areas ¡V economical,organisational, knowledge based, practical and cultural ¡Vwhich are discussed in the thesis. The practical benefits forthe individuals in each profession seem to be the mostimportant reason for adopting IT. Economical factors are thegreatest obstacles to using IT, and few companies are preparedto invest venture capital in advanced systems even if thepotential benefit is great. KEYWORDS:Construction industry, information technology,surveys, CAD, communication / <p>NR 20140805</p>

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Defect inspection is one of the most critical tasks in the industry as it can reduce risks of production stops and assure quality control. In recent years, multiple industries have been adopting computer vision systems, especially based on deep learning techniques, as their main detection methods to improve efficiency, reduce risks and human resources, and enhance real-time performance. However, its adoption in the industry is still limited by the labor-intense and time-consuming process of collecting high-quality custom training datasets. At the same time, many industries have access to the CAD models of the components they want to detect or classify as part of the design process. Taking this into account, in the present work, we analyze the performance of various image classification models to visually detect defects in production. Our method systematically generates synthetic datasets from CAD models using Blender to train neural networks under different settings. The proposed method shows that image classification models benefit from a diversity of the range of defect values during training but struggle to identify low-resolution defects, even for state-of-the-art architectures like Vision Transformer and ConvNext or SqueezeNet, which proved to have comparable performance to these networks. Similarly, adding background, texture, and camera pose to training examples provides more contextual information to image classification models but does not necessarily help them detect the defects accurately. Finally, we observed that using a unique tolerance value for all flange pipe sizes can negatively impact the detection accuracy because, for larger pipe flanges, minor defects are not as perceptible as for small flanges.

In der vorliegenden Studie wurde an 50 3D-gedruckten Molaren mit einer konstruierten Referenzkaries das Ausmaß der vollständigen Kariesentfernung flächenabhängig überprüft. Die untersuchten Zähne wurden mit einer simulierten, standardisierten und mehrflächigen Karies versehen. Studierende der Zahnmedizin haben die Karies entfernt, die Kavität mit einer Aufbaufüllung versorgt und die Zähne für eine Vollkrone präpariert. Um die Kariesentfernung zu bewerten, wurden DVT-Aufnahmen und dreidimensionale Scans angefertigt. Aus den DVT-Datensätzen im DICOM-Format wurden die Aufbaufüllungen der Zähne mithilfe digitaler Bildverarbeitung segmentiert und als eigenständige 3D-Modelle dargestellt. Anschließend erfolgte die Überlagerung der Aufbaufüllungen auf den Referenzzahn aus der Konstruktionsdatei der Zähne. Mit der Konstruktionssoftware Autodesk Fusion 360 wurden die Aufbaufüllungen in Volumenkörper umgewandelt und mit der Karies des Referenzzahnes verglichen. Da sich die Aufbaufüllungen mit der Referenzkaries überschneiden, konnte die Software mit ihrer Teilungsfunktion nicht überschneidende Teile separieren. Abhängig von der Lage der Kavität, in der sich die überschüssigen Volumenkörper befanden, wurden jene als Restkaries oder überexkavierte Zahnhartsubstanz identifiziert. Die gemessenen Volumina von Restkaries ergaben, dass an der distalen Zahnfläche im Vergleich zur bukkalen und okklusalen signifikant mehr Karies verblieben war. Ein weiterer signifikanter Unterschied konnte zwischen mesial und bukkal, jedoch nicht zwischen mesial und okklusal festgestellt werden. Bei der Überexkavation gab es zwischen den Zahnflächen keine Unterschiede. Die Ergebnisse zeigten, dass die Kariesentfernung an den approximalen Zahnflächen für die Studierenden eine höhere manuelle Herausforderung darstellte. Neben der volumetrischen Vermessung ermöglichte die dreidimensionale Visualisierung von Restkaries und der überexkavierten Zahnhartsubstanz eine objektive Bewertung des Behandlungsergebnisses für die Studierenden und deren Ausbilder. Besonders der Vergleich mit einer Referenz schaffte eine valide und nachvollziehbare Beurteilung der Kariesübung an 3D-gedruckten Zähnen. / In the present study, the extent of complete caries removal was checked on 50 3D-printed molars with a constructed reference caries depending on the tooth surface. The examined teeth were created with a simulated, standardized and multi-surface caries. Dental students removed the caries, filled the cavity with a buildup filling and prepared the teeth for a crown. To assess caries removal, CBCT and three-dimensional scans were taken. From the DVT datasets in DICOM format, the buildup fillings of the teeth were segmented using digital image processing and displayed as 3D models. Then the buildup fillings were matched with the reference tooth from the design file of the teeth. With the Autodesk Fusion 360 design software, the buildup fillings were converted into solids and compared to the caries of the reference tooth. Because the buildup fillings overlap with the reference caries, the software was able to separate non-overlapping parts with its splitting function. Depending on the location of the cavity in which the solids were located, those were identified as residual caries or over-excavated tooth structure. The measured volumes of residual caries showed that significantly more caries was left on the distal tooth surface compared to the buccal and occlusal. Another significant difference was found between mesial and buccal, but not between mesial and occlusal. There were no significant differences in overexcavation between the tooth surfaces. The results showed that caries removal on the approximal tooth surfaces is a higher manual challenge for the students. In addition to volumetric measurement, the three-dimensional visualization of residual caries and over-excavated tooth structure enabled an objective evaluation of the treatment result for the students and their trainers. Especially the comparison with a reference allowed a valid and comprehensible assessment of the caries exercise on 3D-printed teeth.

STATEMENT OF PROBLEM: The production of full arch dental models through Rapid Additive Prototyping (3D Printing) have been questioned for their accuracy in the past decade. PURPOSE: To compare the accuracy of 3D printed and milled dental models, using a digital metrology software. MATERIALS AND METHOD: A mandibular arch typodont was duplicated to produce a conventional Type IV dental stone model. This Model was scanned to create a digital model and an STL file was created which would be sent to Milling and 3D printing machines.15 models were printed using 3 different 3D printing companies and 10 models Milled with a CNC (Computerized Numeric Controlled) milling machine. Each model was scanned and a digital model was created. These scanned models were then super imposed to the scan of the master model through an inspection software (Geomagic Control X, 3D Systems) for accuracy of production. RESULTS: The mean difference in measurement in Absolute Gap, by either of the two methods of prototyping adopted, (0.075 mm for 3D Printed and 0.084 mm for milled) are well below the clinically acceptable values mentioned in previous literature. The means in absolute tooth distance discrepancy for both prototyping methods (0.0361 mm for 3DPand 0.0353 mm for Milled) were not statistically significant. CONCLUSION: 3D printed dental models were more accurate statistically than milled dental models. In general, the mean accuracy for both methods of rapid prototyping is within clinical tolerance and both are clinically acceptable.

Optical-based techniques have found merit in measuring displacement and strain for decades. These techniques are commonly used in numerous applications ranging from large displacements in wind tunnel experiments to displacement measurements on the submicron scale. Projection Moiré Interferometry (PMI) is an out-of-plane displacement measurement technique, and consists of capturing reference and deformed images of a grid pattern projected on the test object. By differencing the reference and deformed images of the projected grid pattern, a fringe pattern is generated from which the displacement field can be extracted. This computation requires calibration procedures that analyze a number of fringe patterns from known displacements to compute the fringe sensitivity constant (FSC) values. This process can be time consuming and for large-scale applications, very costly. In addition, due to the projection-oriented nature of this technique, measuring displacements in applications with non-viewable, hidden, or inaccessible reference surfaces excludes the use of PMI. In this thesis, a technique is developed which eliminates calibration procedures through implementation of virtual calibration methods, and typical PMI measurement processes are extended to include digital reference images in determining displacements from inaccessible surfaces. Using camera calibration routines and ray tracing techniques, each major component of the PMI arrangement is modeled as virtual components within a computer simulation where the entire calibration process can be performed. A CAD model of the inaccessible surface is then converted to a point cloud and a surface interpolation function is implemented to generate a displacement field, which can be correlated and differenced from the displacement field of the actual object. Many potential applications exist in the automobile, aerospace, and other manufacturing industries. These industries provide numerous large-scale applications where conventional calibration is not cost-effective. In addition, these applications provide instances where differences between the deformed and reference images represent the manufacturing errors due to dimensional variations and assembly processes. An automated, self-calibrating, whole-field projection measuring system would greatly increase inspection efficiency of large production parts and final assemblies. It is in these types of circumstances that the developed techniques would be of most use.

Product design is a creative process, often subject to rapid and numerous design change requirements. To facilitate geometric redesign iterations, Parametric Computer-Aided Design CAD) systems were introduced. To manage the numerous product design iterations produced by parametric CAD systems, Product Data Management (PDM) systems were developed to capture, document, and manage each product revision. PDM has proved effective thus far at managing design history. However, PDM is built upon database management systems (DBMS), which have the capability of doing far more than simply managing product revision history. Product data consists not only of the physical geometry used to describe it, but also of a host of non-geometric data. This non-geometric data is referred to as attributes. Examples of attributes include material properties, boundary conditions, finite element mesh information, manufacturing operations, assembly operations, cost, etc. Downstream Computer-Aided Engineering (CAE) applications apply attributes to (preprocess) the geometry to perform their respective operations. These attributes are not permanently associated with the geometry and may have to be recreated each time the geometry changes. Preprocessing for highly complex CAE analyses can sometimes require weeks of effort. An attribution method is presented which addresses the creation, storage, and management issues facing attributes in the CAD and CAE environments. The research conducted explores the use of database management systems for defining, instantiating, and managing attributes in the CAD environment. Downstream CAE applications may then retrieve the attributes from the DBMS to automate preprocessing. The attribution system results in standardized attribute definitions, which forms the basis for communicating attributes universally among different downstream CAE applications.

Today's engineering companies rely heavily on an engineer's ability to use computers to analyze and optimize designs. With this use of computers in the design process, products undergo multiple design iterations between preliminary concept and final form. This in turn results in Computer Aided Design (CAD) models being passed from one discipline to the next. In attempts to keep consistency within the design process, an industry wide shift towards the use of CAD master models is taking place. With this change to master models, manufacturing and engineering development companies are attempting to more fully employ the use of parametrics in their initial CAD models. This is in hopes that the initial models handed downstream are robust enough to be used throughout the entire design loop. Unfortunately, current parameter definitions are often not robust enough to incorporate all the design changes from the various analyses and manufacturing operations. To address this problem, we present a more robust parametric methodology that broadens the current definition of parametrics as currently employed on CAx master models within CAD packages.

IP vendors need to keep the internal designs of their IP secret from the IP user for security or commercial reasons. The CAD tools provided by FPGA vendors have some built-in functionality to encrypt the IP. However, the IP is consequently decrypted by the CAD tools in order to run the IP through the design flow. An IP user can use APIs provided by the CAD tools to recreate the IP in an unencrypted state. An IP user could also easily learn the internals of a protected IP with the advent of new open-source bitstream to netlist tools. The user can simply generate a bitstream that includes the protected IP and then use the tools to create a netlist of the third party IP, exposing the internals of IP. Any solution to keep IP protected must keep the IP encrypted through the CAD tools and bitstream generation all the way to FPGA configuration. This thesis presents a design methodology, along with a proof-of-concept tool, that demonstrates how IP can remain partially encrypted through the CAD flow and into the bitstream. It shows how this approach can support multiple encryption keys from different vendors, and can be deployed using existing CAD tools and FPGA families. Results are presented that document the benefits and costs of using such an approach to provide much greater protection for 3rd party IP.