Objectives: To evaluate and compare the color of porcelain veneers with try-in paste in relation to porcelain veneers with permanent cement. Also, to evaluate and compare combinations of three different shades and thicknesses of porcelain veneers and three cement shades before and after final cementation. Additionally, to evaluate and compare the color of porcelain veneers with cured permanent cement before and after aging. Background: Porcelain veneers and ceramic restorations have become one of the most popular approaches in the anterior area due to their natural appearance and esthetics. However, more conservative approaches have led to thinner restorations with increased translucency. A potential drawback to these restorations is that any color change in the luting cement can become clinically visible, and possibly affect esthetic appearance. Methods: One hundred and eight specimens were cut from feldspathic porcelain blocs (Vitablocs Mark II for CEREC). Three different Vita 3D- Master 1M1, 2M2, and 3M1 shades were assessed. All specimens were 12 x 14 mm, with three different thicknesses of 0.3, 0.5, and 1.0 mm. Light-cured resin cement (Variolink Veneer, Ivoclar Vivadent) with three different shades was used. The specimen color alone, with the try-in paste, and with pre-cured and post-cured resin cement was measured using a spectrophotometer (Color Eye 7000A), which measures CIE-L*a*b* values. Specimens were subjected to 30,000 cycles of accelerated aging (Themo-cycling, Sarbi Dental Enterprises Inc.). Color measurement for all specimens was performed again and ∆E values between groups been calculated. Statistical analysis was performed using one-way and three-way ANOVA, with level of significant set at α=0.05, to assess differences between groups. This was followed by post hoc Tukey's tests. Results: Statistical analysis showed a significant difference between try-in paste and corresponding cured resin cement. Pre-cured and post-cured resin cement values showed a significant difference between cement shades. Moreover, statistically significant differences were found between post-cured cement and after 30,000 cycles of thermo-cycling. Conclusions: The final color of porcelain veneers was highly affected by the different shades of resin cement and by the thicknesses of the porcelain veneer. The use of higher ceramic thickness decreased the ∆E values when compared to thinner veneers. Also, color stability of ceramic veneer restorations luted with resin cement, was significantly influenced by the aging.

Indiana University-Purdue University Indianapolis (IUPUI) / Objective: CAD/CAM technology allows fabrication of thin lithium disilicate (LD) veneers to a LD crown substructure in place of using traditional feldspathic porcelain (FP) which has inferior mechanical properties. This project investigated the effect of different LD veneer applications to LD substructure on the biaxial flexural fatigue of LD veneer/substructure restorations. Materials/Methods: Forty-five LD discs (Ø = 120.7 mm) were fabricated that, when combined with the veneering discs, achieve final dimensions of (Ø = 121.2mm). Experimental groups were (n = 15) as follows: (1) Resin Bonded LD Veneer (RBLDV), LD veneer (Ø = 120.5 mm) adhesively cemented to LD (0.7 mm); (2) Sintered LD Veneer (SLDV), LD veneer (Ø=120.5 mm) sintered to LD (0.7 mm); (3) Sintered Feldspathic Veneer (SFV), feldspathic porcelain (FP) applied to LD discs to achieve a final dimension of (Ø = 121.2 mm). A fourth group of (1.2 mm) monolithic LD served as the control. Weibull-distribution survival analysis was used to compare the differences of the resistance to fracture after fatigue between groups. Total number of cycles were analyzed using one-way Anova (p < 0.05). Hypothesis: Adhering or sintering a thin laminate layer of LD on another LD surface would result in increased fracture resistance in comparison to sintered FP on LD. Results: The SFV group had significantly lower fatigue resistance than SLDV and RBLDV groups (p < 0.05). The RBLDV group fractures resulted in significantly more fractured fragments in comparison to the other groups. No statistical difference was observed in the number of cycles. The results also showed that the LD veneered groups presented similar resistance to fatigue as monolithic discs of the same overall dimensions. Conclusion: The hypothesis was accepted suggesting that veneering a LD substructure with a LD veneer, bonded or sintered, has increased resistance to fatigue as FP veneering material on a LD substructure. In addition, it was observed to have similar resistance to fatigue in comparison to the monolithic LD group.

Die vorliegende Bachelorarbeit beschäftigt sich mit der Untersuchung der Tragwerkseigenschaften von Holzleichtbauträgern mit Sperrholzplatten. Die Träger wurden von Herrn Dipl.-Ing. Löser entwickelt und sollen zukünftig als Alternative zu Aluminiumtraversen eingesetzt werden. Das Material dieser Träger wird vorgestellt und bezüglich seiner Definitionen und Zuweisung der Eigenschaften kritisch analysiert. Die Tragfähigkeit und Steifigkeit der Träger wurde bereits in zwei experimentellen Versuchsreihen und in einer Finite-Elemente-Analyse mittels dem Programm RFEM betrachtet. Weiterführend wird eine Analyse der Holzleichtbauträger durch das Programm ANSYS Workbench Version 2022 R2 durchgeführt. Dazu dienten unter anderem eine Netzkonvergenzstudie und verschiedene Parameterstudien. Die Ergebnisse der Bachelorarbeit dienen der Verifikation der Versuchs- und Berechnungsergebnisse und sollen für die Weiterentwicklung des Träger-Konzeptes im Sinne einer gesamtheitlichen Effizienz verwendet werden.:1 Einleitung und Zielsetzung der Arbeit 1.1 Ziel der Arbeit 1.2 Strukturierung der Arbeit 2 Betrachtung der Holzleichtbauträger 2.1 Geometrie der Holzleichtbauträger 2.2 Verwendetes Material - Sperrholz 2.3 Mechanische Eigenschaften von Sperrholz 3 Betrachtung vorliegender Berechnungs- und Messergebnisse 3.1 Auswahl der Trägertypen für weitere Betrachtungen 3.2 Versuchsreihe 1 3.3 Versuchsreihe 2 3.4 RFEM-Modelle 4 ANSYS-Berechnungen der Holzleichtbauträger 4.1 Möglichkeiten der Modellierung von Sperrholz in ANSYS 4.2 Modellierung des FEM-Modells 4.3 Ergebnisse der ANSYS-Berechnungen 4.4 Parameterstudie 5 Auswertung der Ergebnisse 5.1 Sinnvoller Materialansatz für die Modellierung in ANSYS 5.2 Abgleich der Ergebnisse aus ANSYS mit den Versuchsreihen und RFEM 5.3 Untersuchung verschiedener Gegebenheiten 6 Schlussfolgerung und Ausblick Literaturverzeichnis Eidesstattlich Versicherung Anhang / The present bachelor thesis deals with the investigation of the structural properties of lightweight wooden beams with plywood panels. The girders were developed by Dipl.-Ing. Löser and are to be used in the future as an alternative to aluminum trusses. The material of these beams is presented and critically examined with regard to its definitions and assignment of properties. The load capacity and stiffness of the beams have already been considered in two experimental test series and in a finite element method (FEM) using RFEM. Further, an analysis of the lightweight wood beams is carried out by the program ANSYS Workbench version 2022 R2. For this purpose, an investigation of the mesh fineness and various parameter studies were carried out. The results of the bachelor thesis serve to verify the test and calculation results and are to be used for the further development of the girder concept in terms of overall efficiency.:1 Einleitung und Zielsetzung der Arbeit 1.1 Ziel der Arbeit 1.2 Strukturierung der Arbeit 2 Betrachtung der Holzleichtbauträger 2.1 Geometrie der Holzleichtbauträger 2.2 Verwendetes Material - Sperrholz 2.3 Mechanische Eigenschaften von Sperrholz 3 Betrachtung vorliegender Berechnungs- und Messergebnisse 3.1 Auswahl der Trägertypen für weitere Betrachtungen 3.2 Versuchsreihe 1 3.3 Versuchsreihe 2 3.4 RFEM-Modelle 4 ANSYS-Berechnungen der Holzleichtbauträger 4.1 Möglichkeiten der Modellierung von Sperrholz in ANSYS 4.2 Modellierung des FEM-Modells 4.3 Ergebnisse der ANSYS-Berechnungen 4.4 Parameterstudie 5 Auswertung der Ergebnisse 5.1 Sinnvoller Materialansatz für die Modellierung in ANSYS 5.2 Abgleich der Ergebnisse aus ANSYS mit den Versuchsreihen und RFEM 5.3 Untersuchung verschiedener Gegebenheiten 6 Schlussfolgerung und Ausblick Literaturverzeichnis Eidesstattlich Versicherung Anhang

Bolted connection with perpendicular to grain loading has been considered as a high priority research area by Smith and Foliente (2002), for the advancement of the load resistance factor design (LRFD) of connections. The results obtained from the experimental testing of this research will provide information regarding the behavior of connections at conditions of capacity and yield, and a comparison between single and two bolted connections for laminated veneer lumber (LVL) from different manufacturers. Comparison of the experimental results with the predicted results from three models: Technical Report -12 (AF&PA 1999), Van der Put and Leijten (2000) and Jensen et. al. (2003), for single and two bolt connections loaded perpendicular to grain will help in accurately predicting LVL connection behavior. Success in achieving the goals of this research will provide enhancement of knowledge and information for single and two bolted connections loaded in perpendicular to the grain connections for LVL and thereby help in calibrating LRFD parameters on pure reliability basis in future. The variables considered included LVL from two different manufacturers, single and two bolt connections with different bolt sizes and loaded edge distances. The connections were loaded to capacity for all the tests. Tests for the material property input values required for these models were also performed as a part of this research. Connection testing showed splitting failures combined with crushing of main member material and formation of a single plastic moment. Connection resistance increased with increased loaded edge distance and number of bolts. The allowable shear design value controlled the National Design Specification Allowable Stress Design (NDS ASD) lateral design value to the connection design except for one connection configuration with 7D loaded edge distance for two bolts of ½ inch, where connection design strength values controlled. The displacement limit decided for the dowel bearing strength test had a direct impact on the predicted TR-12 capacity values. The capacity resistance calculated by both fracture models increased with increase in loaded edge distances. The Mode-I fracture energy values directly affected the predicted fracture model values. The tension perpendicular to grain strength values directly affected the Jensen model values. Statistical comparison of 4D and 7D loaded edge distances and LVL-1 and LVL-2 material revealed that Van der Put model had no difference in the calculated to test (C/T) ratios with respect to different loaded edge distances and materials and the Jensen model predicted the C/T ratios at 4D to be significantly greater than at 7D and for LVL-1 to be significantly greater than LVL-2. Van der Put model over predicts at capacity and the C/T values are consistent with change in loaded edge distance. Jensen model C/T ratios over predicted for single bolt connection and predicts accurate for two bolt connection with respect to loaded edge distances. Comparing the two fracture models with a ductile model TR-12 with respect to different loaded edge distances, material, number and size of bolts, Jensen model best predicted the C/T ratios. The Van der Put model tended to over predict values, while the TR-12 model had no consistent trend in C/T ratios, but seemed to be affected inversely by changes in loaded edge distance. / Master of Science

No description available.

No description available.

The research summarized by this thesis was comprised of an experimental analysis of beams loaded perpendicular to grain at midspan by a bolted double-shear laterally-loaded connection. Connection specimens were loaded monotonically until capacity was reached. Variables of consideration included the loaded edge distance of the connection main member, the span:depth ratio of the main member, and the main member material. Southern pine machine-stress-rated (MSR) lumber, laminated veneer lumber (LVL), and parallel strand lumber (PSL) were the three material types included in the program. Experimental results were compared with theoretical predictions from three models: the yield theory-based general dowel equations, which are currently the standard for laterally-loaded connection design in the U.S., and two models based upon fracture mechanics. All material property inputs required by the three models, were measured in the experimental program of this research and used to produce theoretical predictions. Comparisons were also made with respect to design values in the form of calculated factors of safety, over-strengths, and design factors of safety. Test results and observed trends are provided for all connection and material property tests. Notable trends included failure by splitting for all connections at low loaded edge distances, and variable span:depth ratios generally having a negligible effect on both connection and model performance. In most cases, the general dowel equations were more accurate than the two fracture models, however it should be noted that all three models over-predicted connection capacity at low loaded edge distances. / Master of Science

this thesis Presents an exploration of the residence hall as an institution through formal and conceptual play. / Master of Architecture

This research compared the results of three tests: ASTM D 198 torsion, ASTM D 198 three-point bending and the five-point bending test (FPBT) using machine-stress-rated (MSR) lumber and laminated veneer lumber (LVL) to determine if the shear properties evaluated by the different test methods were equivalent. Measured E:G ratios were also compared to the E:G ratio of 16:1 commonly assumed for structural wooden members. The average shear moduli results showed significant differences between the three test methods. For both material types, the shear moduli results determined from the two standard test methods (ASTM D 198 three-point bending and torsion), both of which are presently assumed to be equivalent, were significantly different. Most average E:G ratios from the two material types and three test methods showed differences from the E:G ratio of 16:1 commonly assumed for structural wooden members. The average moduli of elasticity results for both material types were not significantly different. Therefore, the lack of significant difference between moduli of elasticity terms indicates that differences between E:G ratios are due to the shear modulus terms. This research has shown differences in shear moduli results of the three test types (ASTM D 198 torsion, ASTM D 198 three-point bending, and the FPBT). Differences in the average E:G ratios per material and test type were also observed. / Master of Science

Durch die Entwicklung der vorgestellten modularen Bauweise ist es möglich, Maschinengestelle aus Holzfurnierlagenverbundwerkstoff (WVC) einfach herzustellen und technisch sinnvoll einzusetzen. Die modulare Bauweise kann sowohl für statische als auch dynamische Beanspruchungen im Allge-meinen Maschinenbau angewendet werden. In einem Baukastensystem werden Maschinenteile aus WVC durch geeignete Verbindungsmittel lösbar zusammengesetzt. Damit ist es möglich, eine hohe Flexibilität in der späteren Nutzung mit einer hohen Variantenvielfalt des Aufbaus durch entsprechend verschiedene Bauteile zu kombinieren. Im Vortrag werden die verschiedenen Belastungen des Holzverbundes im Maschinenaufbau charakte-risiert und auf Probleme bei der Konstruktion eingegangen. Abschließend werden Ergebnisse zu Dau-eruntersuchungen der Verbindungstechnik und des gesamten Maschinenaufbaus vorgestellt und diskutiert. / The development of the presented modular construction allows to manufacture wood veneer compos-ite (WVC) machine racks easily in a technical reasonable way. The modular construction can be used for both static and dynamic loading conditions in mechanical engineering. In the modular construction system the WVC machine components are connected detachable with adequate fasteners. This leads to high flexibility during the construction and assembly process of machine components. In the current presentation the different loading conditions of WVC profiles are characterized and the problems during construction described. Finally the results of the long term testing of the connection technique are presented and the complete machine system is discussed.