Indiana University-Purdue University Indianapolis (IUPUI) / The current movement in dentistry is to provide treatment that is evidence-based rather than opinion-based. Unfortunately, there is a lack of evidence for most orthodontic appliances. Much work has been done to find the appropriate load system to move teeth, but research has only been done with laboratory techniques that may not be applied clinically. Ideally, appliances should be tested in all three dimensions with techniques (e.g. type of ligation) that replicate clinical procedures. This can be accomplished with a new patented technology, the orthodontic force tester (OFT). The OFT allows an entire arch with brackets and a full arch wire to be set up while measurements are made on target teeth. With the OFT, appliances can be tested to ascertain if they provide the prescribed load system, and if not, then modify them or develop new ones. In this experiment two different commercially available prefabricated closing loop arch wires (keyhole and teardrop) were tested with variations in gable bends, interbracket loop position, and activation. The application being tested is closing space between a lateral incisor and canine in a first premolar extraction case after the canine has been retracted. While the trend shows that the keyhole loop produces higher overall force the two loops are not significantly different in the forces or moments that they generate. The one exception is that the keyhole loop produces higher lingual forces at the canine when the loop is in the mesial position. Also, few wire configuration were able to produce M/F sufficient to translate teeth. The wire configurations that can provide the proper load system to translate teeth in the lingual direction at the incisor were in the mesial position and had second order gable bends at the alpha position. The loop design had little effect on the M/F ratios.

Indiana University-Purdue University Indianapolis (IUPUI) / Several studies have shown endosseous implants placed in areas of thick cortical bone to be an effective means of anchorage in complex orthodontic cases. The purpose of this study was to examine the viability of endosseous implants as orthodontic/orthopedic anchorage when placed in this cancellous bone. Eighteen 6-month-old male rabbits were used and stratified into three groups of six animals. Two implants placed (bilaterally) in the dorsal surface of the nasal bones. After a 12-week healing period, the control group (C) had a passive spring placed between the implants, and the 1 Newton constant group (1 NC) received a spring that delivered a constant compressive load of 1N. A 1N load was applied to the progressive load group (3NP) and sequentially increased to 3N over the course of the study. Bone labels were administered throughout the experiment at designated time intervals to provide quantification of the physiologic activity. Following histologic processing, analyses were conducted on midfrontal sections using microradiography and fluorescent microscopy. The implants were divided into three regions: supraflange, coronal, and apical. Within each region the percent woven and lamellar bone was recorded as well as the percent bone in contact with or near the implant surface. Remodeling activity was observed by using fluorescent bone labels. In the sections analyzed using fluorescent microscopy, the regions were further subdivided into zones. Using the bone label data, bone was categorized as old bone, new woven bone, new lamellar bone and marrow space. Within animal, paired t tests revealed no significant difference between right/left implants. Data was pooled and an ANOVA run to test for difference between groups. Few significant differences were seen. Student Newman-Keuls sequential range tests were used to test between region and zone. The coronal region showed trends of more bone overall in the 1NC and the 3NP load groups p < 0.10. The apical region had less bone overall. The fluorescent data showed few significant differences between groups; however, the coronal region showed trends of more bone overall. A RAP effect was observed in the zonal analysis for new lamellar bone. Sutural remodeling was observed at the cortical plate over the nasal suture. A significant trabecular response was not seen in this study; however, the implants in the experimental groups remained stable throughout the study possibly due to the implant design. It was concluded that implants placed in thin cancellous bones are suitable for use as orthodontic/orthopedic anchorage.

Indiana University-Purdue University Indianapolis (IUPUI) / Orthodontic closing loops offer an efficient way to control the moment to force ratios (M/F) delivered during space closure. The triangular loop is often used in the Graduate Orthodontic Clinic at the Indiana University School of Dentistry. Previous studies on the triangular loop were concerned with various loop geometries. The present project was designed to study the triangular loop in a clinically realistic experimental set up. Compared to the previous studies, three major changes were implemented: instead of two coplanar brackets, the current study employed a bracketed typodont arch (1) the effects of loop locations (2) and different interbracket distances were considered (3). The measured moment and forces reflect considerable differences in the systems due to the new experimental set up. As in previous studies, the triangular loops were fabricated from 0.016 X 0.022- inch stainless steel wire. The loops were equilateral triangles with 8 mm sides, ligated to the arch wire by elastomeric rings. There were 4 loop locations: location 1 was at 1.2 mm away from the mesial bracket; location 2 was at 3 .2 mm away from the distal bracket; location 3 was centered in the middle of the original interbracket distance; location 4 was located 2.6 mm away from the mesial bracket. There were three interbracket distances (IB). The original IB (IBl) of 12.6 mm was decreased by 3 mm (IB 2) and by 6 mm (IB 3). The loops were activated by 1.6 mm and 3.3 mm. Force and moment components were measured along three mutual perpendicular axes (x, y, and z) corresponding to the buccolingual, mesiodistal, occlusogingival axes respectively. Comparisons of Mx/Fy and Mz/Fy at the mesial and distal, by three activation levels, three interbracket distances, and four locations, and all interaction effects, were performed using a mixed design repeated measures ANOV A procedure. The General Linear Model (GLM) procedure for unbalanced designs was used because not all interbracket distances could be accommodated with all loop locations. Activation distance was the within specimen repeated factor. Loop location and interbracket distance were the between specimen factor. It was theorized that the location of the triangular loop, as well as the interbracket distance, have a considerable effect on the generated M/F. The Null Hypothesis was that there are no significant differences (p > 0.05) in the M/F ratios generated by the triangular loop as the loop position changes relative to the brackets, and there are no significant differences (p>0.05) in the M/F ratios generated by the triangular loop as the interbracket distance becomes shorter with space closure. Statistical significant interactions were found for Mx/Fy and Mz/Fy at location 2, for all activations, at both the mesial and distal measures. Therefore we rejected the first part of the Null Hypothesis (no differences as the loop location changes), and accept the second part (no differences as the interbracket distance shortens). We were able to see clear trends at all loop locations, as well as interbracket distances, and draw useful clinical implications. We found that the mesial closing forces are quite small when compared to those at the distal. We attributed this discrepancy to the U shape geometry of the continuous arch wire technique. We observed that if closing loops are delivered with no activation, then counterproductive M/F ratios are produced. Our data also indicated that anchorage becomes more critical as the interbracket distance shortens. Finally, we determined that wire tie ligation for prevention of rotation along the long axis of the tooth is especially important for the lateral incisor.

Vi lever i en tid där tillgången till energi är en fråga som berör en stor del av jordens befolkning. Efterfrågan på förnybara bränslen ökar och fasta bränslen såsom exempelvis ved blir ett alltmer attraktivt alternativ vid uppvärmning av hushåll. För att framställa ved för detta ändamål är de mest användbara vedklyvarna idag stora och lämpade för utomhusmiljöer. De alternativ som är någorlunda kompakta och som skulle kunna användas i inomhusmiljöer är dock manuella konstruktioner som kräver precision och handkraft. Det gör dem mindre användarvänliga till den större massan och produkten lämpar sig mindre bra till användare som, av olika anledningar, inte är kapabla att använda muskelkraft för att klyva veden. Målet med detta examensarbete var att ta fram ett konceptförslag på en vedklyv för inomhusbruk som syftar till att förbättra möjligheterna för klyvning av ved inomhus. Marknadsanalys och litteraturstudier har använts som metod i syfte att landa i en kravspecifikation. Litteraturstudien gav information om nödvändig klyvkraft beroende på träslag och dimensioner. Arbetet resulterade i ett koncept som möjliggör klyvning av tändved med upptill fem ton klyvkraft. Konceptet består i sin helhet av en elektrisk saxdomkraft och en ställning med till hörande bottenplatta och en kilklyv. Vidare möjliggör designen av ställningen att klyvkilens höjd kan justeras. Dimensionering av konstruktionens delar är dels baserade på fraktkostnader hos USPS, dels på att rätt mekanismen skall fungera enligt önskemål. Vedklyven visualiseras som CAD-modell där val av material och färg grundar sig arbetets konceptdefinition och konceptgenereringsfas. / We live in a time where access to energy is an issue that affects a large part of the world's population. The demand for renewable fuels is increasing, and solid fuels such as wood are becoming an increasingly attractive alternative for heating households. To produce wood for this purpose, the most serviceable log splitters today are large and suitable for outdoor environments. However, the reasonably compact alternatives that could be used in indoor environments are manual constructions that require precision and hand strength. These factors make them less user-friendly to the larger mass, and the product is less suited to users who, for various reasons, cannot use muscle power to split the wood. The objective of this thesis was to develop a concept proposal for a wood splitter for indoor use that aims to improve the possibilities for splitting wood indoors. The project commenced with market analysis, and literature studies have been used as methods in order to determine the most essential requirements. The literature study provided information on the necessary splitting force depending on the wood species and dimensions. The project result is a concept that enables firewood splitting with up to five tonnes of splitting force. The concept consists entirely of an electric scissor jack, a stand with an associated base plate, and a wedge splitter. Furthermore, the design of the stand enables the height of the splitting wedge to be adjusted. Dimensioning of the construction's parts is partly based on shipping costs at USPS and partly on the proper mechanism to function as desired. The log splitter is visualized as a CAD model where the choice of material and color is based on the concept definition and concept generation phase.

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This paper presents a semianalytical method for the prediction of interlaminar stresses and displacements near the free edges and ply cracks in general angle-ply laminates subjected to biaxial extensions and/or in plane shear deformation. The method is based on a state space representation of the three-dimensional equations of elasticity. Numerical solutions are obtained by using layer refinement in the through thickness direction and Fourier series expansion in the other directions. By this approach, an angle-ply laminate may be composed of an arbitrary number of monoclinic layers and each layer may have different material property and thickness. This method guarantees continuous fields of all interlaminar stresses across interfaces between material layers. Numerical results are compared with those obtained from other methods. It is found that the theory provides a satisfactory approximation to the stress singularities near the free edges and ply cracks. Numerical solutions for antisymmetric laminates under extension and general laminates under shearing are new in the literature and can be used as benchmarks for validating new models.

One of the key issues concerning the durability of composites is the strength and stiffness degradation during service. Traditionally, these materials have been analyzed by methods which do not take into account variations in the material at the fiber/matrix level. In addition, manufacturing techniques have advanced enough so that composites can be designed from the fiber/matrix level up. As a result, it is important to predict the effect microlevel variations in the material have on macroscopic behavior. Therefore, it is vital to use a micromechanics model to calculate stress and displacement variations. In this study, the strength and stiffness of polymer matrix composites will be determined. To accomplish this, a variational model which calculates microstresses and strains due to damage is used in conjunction with a statistical strength model to predict strength. The results are compared to experimental results of uniaxial strength of carbon fiber composites. In addition, the stiffness of a continuous fiber composite was predicted and compared to a rule of mixtures equation of stiffness. A comparison showed very good agreement. To study the effect of damage, the stiffness of a continuous fiber composite with fiber fragmentation is predicted as a function of fragmentation length and fiber volume fraction. Finally the stiffness of a short-fiber composite is predicted and compared to analytical and experimental results. / Master of Science

No / Axially loaded rubber blocks of long, thin rectangular and circular cross section whose ends are bonded to rigid plates are studied. Closed-form expressions, which satisfy exactly the governing equations and conditions based upon the classical theory of elasticity, are derived for the total axial deflection and stress distribution using a superposition approach. The corresponding relations are presented for readily calculating the apparent Young's modulus, Ea, the modified modulus, E'a, and the deformed lateral profiles of the blocks. From these, improved approximate elementary expressions for evaluating Ea and E'a are deduced. These estimates, and the precisely found values, agree for large values of the shape factor S, with those previously suggested, but also fit the experimental data more closely for small values of S. Confirmation is provided that the assumption of a parabolic lateral profile is invalid for small values of S.