Particleboard (PB) is a widely used panel material because of its physical properties and low cost. Unfortunately, cutting can degrade its surface creating rejects and increasing manufacturing costs. A major challenge is PB’s internal variability. Different particle and glue bond strength combinations can sometimes create high quality surfaces in one area and defects such as edge chipping in nearby areas. This research examines methods of improving surface quality by examining PB characteristics and their interactions with the cutting tool. It also develops an analytical model and software tool that allows the effects of these factors to be simulated, thereby giving practical guidance and reducing the need for costly experiments. When PB is cut and the glue bond strength is weaker than the particle strength, particles are pulled out, leading to surface defects. When instead the glue bond strength is stronger than the particle strength, particles are smoothly cut, leading to a high quality surface. PB is modeled as a matrix of particles each with stochastically assigned material and glue bond strengths. The PB model is layered allowing particles to be misaligned. Voids are modeled as missing particles. PB cutting is modeled in three zones. In the finished material and tool tip zones, particles are compressed elastically and then crushed at constant stress. After failure, chip formation occurs in the chip formation zone. At large rake angles, the chip is modeled as a transversely loaded beam that can fail by cleavage at its base or tensile failure on its surface. At small rake angles, the chip is modeled as the resultant force acting on the plane from the tool tip through to the panel surface. Experimental and simulation results show that cutting forces increase with depth of cut, glue content and particle strength. They decrease with rake angle. Glue bond strength can be increased to the equivalent particle strength through the selection of particle geometry and the subsequent increased glue bond efficiency, which increases the cut surface quality without the need for additional glue. Minimizing the size and frequency of voids and using larger rake angles can also increase surface quality.

The bony fin rays of the zebrafish caudal fin are a convenient system for studying bone morphogenesis and patterning. Joints and bifurcations in fin rays follow predictable spatial patterns, though the mechanisms underlying these patterns are not well understood. We developed simulation models to explore ray pattern formation mechanisms in growing fins. In all models, the fin ray growth rates are based on quantitative experimental data. The different models simulate ray joint formation and bifurcation formation using different hypothetical mechanisms. In the most plausible model, ray joint and bifurcation formation result from the accumulation of two substances, arbitrarily named J and B. Model parameters were optimized to find the best fit between model output and quantitative experimental data on fin ray patterns. The model will be tested in the future by evaluating how well it can predict fin ray patterns in different fin shapes, mutant zebrafish fins, and other fish species.

A computer simulation model of a springboard and a diver was developed to investigate diving takeoff techniques in the forward and the reverse groups. The springboard model incorporated vertical, horizontal and rotational movements based on experimental data. The diver was modelled as an eight-segment link system with torque generators acting at the metatarsal-phalangeal, ankle, knee, hip and shoulder joints. Wobbling masses were included within the trunk, thigh and shank segments to allow for soft tissue movement. The foot-springboard interface was represented by spring-dampers acting at the heel, ball and toes of the foot. The model was personalised to an elite diver so that simulation output could be compared with the diver's own performance. Kinematic data of diving performances from a one-metre springboard were obtained using high speed video and personalised inertia parameters were determined from anthropometric measurements. Joint torque was calculated using a torque / angle / angular velocity relationship based on the maximum voluntary torque measured using an isovelocity dynamometer. Visco-elastic parameters were determined using a subject-specific angledriven model which matched the simulation to the performance in an optimisation process. Four dives with minimum and maximum angular momentum in the two dive groups were chosen to obtain a common set of parameters for use in the torque-driven model. In the evaluation of the torque-driven model, there was good agreement between the simulation and performance for all four dives with a mean difference of 6.3%. The model was applied to optimise for maximum dive height for each of the four dives and to optimise for maximum rotational potential in each of the two dive groups. Optimisation results suggest that changing techniques can increase the dive height by up to 2.0 cm. It was also predicted that the diver could generate rotation almost sufficient to perform a forward three and one-half somersault tuck and a reverse two and one-half somersault tuck.

abstract: Advances in software and applications continue to demand advances in memory. The ideal memory would be non-volatile and have maximal capacity, speed, retention time, endurance, and radiation hardness while also having minimal physical size, energy usage, and cost. The programmable metallization cell (PMC) is an emerging memory technology that is likely to surpass flash memory in all the listed ideal memory characteristics. A comprehensive physics-based model is needed to fully understand PMC operation and aid in design optimization. With the intent of advancing the PMC modeling effort, this thesis presents two simulation models for the PMC. The first model is a finite element model based on Silvaco Atlas finite element analysis software. Limitations of the software are identified that make this model inconsistent with the operating mechanism of the PMC. The second model is a physics-based numerical model developed for the PMC. This model is successful in matching data measured from a chalcogenide glass PMC designed and manufactured at ASU. Matched operating characteristics observable in the current and resistance vs. voltage data include the OFF/ON resistances and write/erase and electrodeposition voltage thresholds. Multilevel programming is also explained and demonstrated with the numerical model. The numerical model has already proven useful by revealing some information presented about the operation and characteristics of the PMC. / Dissertation/Thesis / PMC numerical model written in M for Octave/MATLAB / M.S. Electrical Engineering 2013

Mathematical relationships have long been used to describe many aspects of muscle function such as the relationship between muscle force and muscle length, muscle force and velocity of contraction or the degree of muscle activation during a contraction. During this work various mathematical expressions have been employed in order to gain an insight into different aspects of muscle activity. The first part of the work examined whether performing a strength protocol on a dynamometer can lead to an increase in eccentric strength output as well as in the neuromuscular activation of the quadriceps group of muscles that appears inhibited during slow concentric and fast eccentric contractions. Neuromuscular activation was modelled via a three-parameter sigmoid function that was also tested for robustness to perturbations in the maximum activation values. During the second part of the study the "functional" hamstrings to quadriceps ratio H:Qfun was expressed as a function of two variables i.e., angular velocity and joint angle. Initially nine-parameter torque-angular velocity-angle profiles were obtained for the knee extensors and flexors from a group of participants. A theoretical 17- parameter H:Qfun function was then derived for each dataset. Subsequently, a simpler, 6-parameter function was derived, RE = aexp(bωn + cθm)-dω1/2θ2 that best reproduced the original 17-parameter fit. Finally, a six-segment subject specific torque-driven model of the Snatch lift was developed in order to investigate the optimal mechanics of the lift. The model simulated the lift from its initiation until the end of the second pull when the feet of the athlete momentarily leave the platform. The six-segment model comprised of foot, shank, thigh, torso (head + trunk), arm and forearm segments with torque generators at the ankle, knee, hip and shoulder joints respectively. The torque profiles were obtained using an isokinetic dynamometer.

Particleboard (PB) is a widely used panel material because of its physical properties and low cost. Unfortunately, cutting can degrade its surface creating rejects and increasing manufacturing costs. A major challenge is PB’s internal variability. Different particle and glue bond strength combinations can sometimes create high quality surfaces in one area and defects such as edge chipping in nearby areas. This research examines methods of improving surface quality by examining PB characteristics and their interactions with the cutting tool. It also develops an analytical model and software tool that allows the effects of these factors to be simulated, thereby giving practical guidance and reducing the need for costly experiments. When PB is cut and the glue bond strength is weaker than the particle strength, particles are pulled out, leading to surface defects. When instead the glue bond strength is stronger than the particle strength, particles are smoothly cut, leading to a high quality surface. PB is modeled as a matrix of particles each with stochastically assigned material and glue bond strengths. The PB model is layered allowing particles to be misaligned. Voids are modeled as missing particles. PB cutting is modeled in three zones. In the finished material and tool tip zones, particles are compressed elastically and then crushed at constant stress. After failure, chip formation occurs in the chip formation zone. At large rake angles, the chip is modeled as a transversely loaded beam that can fail by cleavage at its base or tensile failure on its surface. At small rake angles, the chip is modeled as the resultant force acting on the plane from the tool tip through to the panel surface. Experimental and simulation results show that cutting forces increase with depth of cut, glue content and particle strength. They decrease with rake angle. Glue bond strength can be increased to the equivalent particle strength through the selection of particle geometry and the subsequent increased glue bond efficiency, which increases the cut surface quality without the need for additional glue. Minimizing the size and frequency of voids and using larger rake angles can also increase surface quality. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

The bony fin rays of the zebrafish caudal fin are a convenient system for studying bone morphogenesis and patterning. Joints and bifurcations in fin rays follow predictable spatial patterns, though the mechanisms underlying these patterns are not well understood. We developed simulation models to explore ray pattern formation mechanisms in growing fins. In all models, the fin ray growth rates are based on quantitative experimental data. The different models simulate ray joint formation and bifurcation formation using different hypothetical mechanisms. In the most plausible model, ray joint and bifurcation formation result from the accumulation of two substances, arbitrarily named J and B. Model parameters were optimized to find the best fit between model output and quantitative experimental data on fin ray patterns. The model will be tested in the future by evaluating how well it can predict fin ray patterns in different fin shapes, mutant zebrafish fins, and other fish species.

In this thesis, called a simulation model of population growth, there was created the simulation model of a population growth in the Czech Republic to the year 2052. First there was constructed the projection through the component method used in demography. Deterministic values obtained by this method are then used in the simulation analysis. In the simulation analysis there was conducted an experiment with three variables which influence the population growth (the fertility, life expectancy/the coefficient of the decline of the probability of the death/ and the migration balance). With the support of the Crystal Ball, supporting program for Excel, which provides the possibility of the simulations, there was determined the stochastic character of the three variables. There are created the low, medium and high variant of the projections, as well as three other possible variants of population growth that might occur. These variations are called economic crisis, friendly migration policy and restrictive migration policy.

The aim of this thesis is to analyze and optimize production processes in a company which produces plastic components for the automotive industry. The theoretical part of this thesis summarizes basic knowledge of business process simulation and addresses the reasons for making use of dynamic simulation as a tool for eliminating dissipation and supporting decision making. The main focus is an analysis of the current situation and identifies the problems in the company. For the purpose of optimization, a simulation model was created using Simul8, by the Simul8 Corporation. The model was made in accordance with the methodology described in the theoretical part of this thesis. It was used to examine the efficiency of proposed versions of the production schedule, in light of its impact on storage capacity and service level.

När tiden för utveckling av nya produkter kortas ner måste testning och verifiering utföras i ett tidigare utvecklingsstadie. Genom simulering av systemet kan tester utföras utan tillgång till det faktiska systemet och därmed kan utvecklingsprocessen accelereras. I BAE Systems Hägglunds stridsvagnar används en tröghetsnavigator som kan beräkna stridsvagnens position utan externa referenser. Test och verifiering av navigation med denna enhet i testbänk är ej fullt möjligt. Syftet med detta arbete är att kunna genomföra verklighetstrogna tester, i testbänk i utvecklingsfasen, genom att simulera navigatorns funktioner. Eftersom kommunikation med fordonssystemet ska ske i realtid samtidigt som navigationsdata läses från ett externt program, så ställs krav på att modellen har tillräcklig prestanda för att ge en verklighetstrogen simulering. Den övergripande frågeställningen i detta examensarbete är om en modell realiserad på en mikrokontroller (MCU) har tillräcklig prestanda för att användas vid simulering av en tröghetsnavigator. För att besvara frågeställningen har hårdvara för anpassning av gränssnittet mellan fordonssystem, MCU och externt program samt mjukvara för att simulera en tröghetsnavigator skapats. Därefter har modellen verifierats genom att mäta tiden för utvalda processer. Alla funktioner hos navigatorn har inte implementerats i simuleringsmodellen men resultaten visar att modellen kan användas för verklighetstrogna tester i testbänk. / When time for development of new products is shortened, testing and verification must be performed at an earlier stage of development. By simulating the system, tests can be performed without access to the actual system and thus the development process can be accelerated.  BAE Systems Hägglunds manufacture combat vehicles and use an Inertial Navigation System (INS) to calculate the combat vehicle’s position without external references. Testing and verification of navigation with this unit in the test bench is not entirely possible.  The aim of this thesis is to enable realistic tests, in a test bench in the development phase, by simulating the navigator’s functions. Since communication with the Vehicle Control System (VCS) must take place in real time at the same time as navigation data must be read from external program, the model is required to have sufficient performance to provide a realistic simulation.  The overall question in this thesis is whether a model realized on a microcontroller (MCU) has sufficient performance to be used for simulation of an INS. To answer the question at issue, hardware for adapting the interface between the VCS, MCU and external program as well as software for simulating an INS have been created. Thereafter, the model has been verified by measuring the time for selected processes.  Not all functions of the navigator have been implemented in the simulation model, but the results show that the model can be used for realistic tests in the test bench.