Configurable Seat Track Latching Mechanism

The reconfigurable seating system is a flexible seating solution for transit vehicles that allows operators to change the configuration of the floor plan in a timely manner in order to accommodate change in needs. This project consists of three senior project teams each working on a component of the design: system, track & latch, and articulation. Descriptions of the responsibilities of each team will be discussed below

Stochastic Analysis: Geometry of Random Processes

A common feature shared by many natural objects arising in probability theory is that they tend to be very “rough”, as opposed to the “smooth” objects usually studied in other branches of mathematics. It is however still desirable to understand their geometric properties, be it from a metric, a topological, or a measure-theoretic perspective. In recent years, our understanding of such “random geometries” has seen spectacular advances on a number of fronts

The distribution and abundance of the rook corvus frugilegus L. as influenced by habitat suitability and competitive interactions.

Rooks (Corvus frugilegus) are colonially breeding corvids found in most agricultural landscapes. Colonies in the County Durham area tend to be clustered at distances up to 500 m, but otherwise show little pattern in terms of spacing or size. Colony size was comparable between sites as changes in colony nest counts were allowed to stabilise before the whole area was surveyed. When measuring nest build-up at a sample of colonies in 1996, no further significant increases occurred after 9th April. The spatial size distribution of colonies was maintained between years. The distribution and size of breeding colonies is modelled in relation to the interaction between the spatial distribution of the foraging habitat and potential intraspecific competitors, with the identification of the distance over which this interaction is strongest. The satellite derived habitat data used for the modelling were part of the ITE Land Cover Map of Great Britain. However, their correspondence with ground reference data was found to be severely lacking. Thus, for modelling the availability of nesting habitat, OS woodland data were used as these identified more of the extant rookery sites, whilst the ITE data were retained for quantifying the foraging habitat. Logistic regression showed that the distribution of colony sites was influenced by the availability of woodland blocks large enough to hold a colony, proximity to roads and buildings, and by the amount of pasture within 1 km. Other suitable sites with these characteristics remained unoccupied within the distribution. Partial Correlations showed that interactions between the spatial distribution of the foraging habitat and competitors influenced colony size at distances up to 6 km, suggesting their effect outside of the breeding season. The multiple regression model built with variable values for this distance explained 31% of the variance in colony size. When applied to the potential breeding sites identified using the logistic regression, most sites still remained suitable. This suggests the distribution is not saturated and that limited availability of breeding habitat is not the cause of the nesting aggregations. The broad correlation of Rook abundance to foraging habitat and potential competitors corresponds to an ideal free distribution of individuals across colony sites. This is supported by models of Rook numbers in relation to parish agricultural statistics produced by MAFF. These again show the importance of pasture as a probable foraging resource, and how pasture quality could be important to Rook numbers. The models also supported the ideal free predictions of spatial variation in Rook abundance in relation to habitat, and the response of colony sizes to temporal change in habitat quality

Morphological And Genetic Variability Of Malaysian Channa Spp Based On Morphometric And RAPD Techniques [QL638.C486 N82 2007 f rb].

Satu kajian morfometrik dan genetik telah dijalankan ke atas enam daripada tujuh spesies yang telah didokumenkan di Semenanjung Malaysia; Channa striata, C. gachua, C. marulioides, C. micropeltes, C. melasoma and C. lucius. Lapan belas ukuran pandangan sisi and 11 ukuran pandangan dorsal telah diperolehi daripada 81 individu. A morphometric and genetic study were conducted on six of the seven species that have been documented in Peninsular Malaysia; Channa striata, C. gachua, C. marulioides, C. micropeltes, C. melasoma and C. lucius. Eighteen side view and 11 dorsal view measurements were obtained from 81 individuals

Voxel-Based Solution Approaches to the Three-Dimensional Irregular Packing Problem

Research on the three-dimensional (3D) packing problem has largely focused on packing boxes for the transportation of goods. As a result, there has been little focus on packing irregular shapes in the operational research literature. New technologies have raised the practical importance of 3D irregular packing problems and the need for efficient solutions. In this work, we address the variant of the problem where the aim is to place a set of 3D irregular items in a container, while minimizing the container height, analogous to the strip packing problem. In order to solve this problem, we need to address two critical components; efficient computation of the geometry and finding high-quality solutions. In this work, we explore the potential of voxels, the 3D equivalent of pixels, as the geometric representation of the irregular items. In this discretised space, we develop a geometric tool that extends the concept of the nofit polygon to the 3D case. This enables us to provide an integer linear programming formulation for this problem that can solve some small instances. For practical size problems, we design metaheuristic optimisation approaches. Because the literature is limited, we introduce new benchmark instances. Some are randomly generated and some represent realistic models from the additive manufacturing area. Our results on the literature benchmark data and on our new instances show that our metaheuristic techniques achieve the best known solutions for a wide variety of problems in practical computation times

Morphological Evolution Of The Scapula In Tree Squirrels, Chipmunks, And Ground Squirrels (Sciuridae): An Analysis Using Thin‐Plate Splines

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137581/1/evo01274.pd

Design and computational optimization of a flexure-based XY nano-positioning stage

This thesis presents the design and computational optimization of a two-axis nano-positioning stage. The devised stage relies on double parallelogram flexure bearings with under-constraint eliminating linkages to enable motion in the primary degrees-of-freedom. The structural parameters of the underlying flexures were optimized to provide a large-range and high bandwidth with sub-micron resolution while maintaining a compact size. A finite element model was created to establish a functional relationship between the geometry of the flexure elements and the stiffness behavior. Then, a neural network was trained from the simulation results to explore the design space with a low computational expense. The neural net was integrated with a genetic algorithm to optimize the design of the flexures for compactness and dynamic performance. The optimal solutions resulted in a reduction of stage footprint by 14% and an increase in the first natural frequency by 75% relative to a baseline design, all while preserving the same 50mm range in each axis with a factor of safety of 2. This confirms the efficacy of the proposed approach in improving stage performance through an optimization of its constituent flexures.Mechanical Engineerin

Modeling underwater visual ability and varied color expression in the diamondback terrapin (Malaclemys terrapin) in relation to potential mate preference by females

Color vision is utilized by animals to navigate the environment, distinguish between objects (e.g. prey and conspecifics), perceive differences in fitness between potential mates, as well as a number of other visual tasks. Color vision varies greatly among species and as a consequence a visual signal varies greatly in how it is perceived. The conditions of the environment additionally impact the ability of an animal to perceive the intrinsic value of a visual signal. The field of visual ecology has only recently received a great deal of attention due to technological advancements that allow objective measures of animal coloration. However, ease of organismal sampling has created a bias in the literature, with avian and mammalian taxa garnering greater attention than reptilian taxa. The estuarine diamondback terrapin (Malaclemys terrapin), hereafter called terrapin, is an aquatic turtle facing human-induced population declines. Population models and estimates of viability only hold under the assumption of random mating, which is often not the case. In this study I tested the hypothesis that female terrapins exhibit preferences for mates with color or color patterns that differ from the general population. I captured gravid females and males in Barnegat Bay, New Jersey as part of a long term population study conducted by my lab. To determine if non-random mating is occurring in the Barnegat Bay terrapin population, I conducted a paternity analysis on hatchlings that were obtained from captured gravid females. I genotyped blood samples for six highly polymorphic microsatellite loci from all adult males and gravid females, and tissue samples from all hatchlings. To determine whether genotype-matched fathers exhibited color phenotypes different from the population, I implemented the three concepts of visual ecology: (1) measure physiological visual ability, (2) measure the visual target being perceived, and (3) measure the light environment in which the visual target is perceived. I found four distinct classes of photoreceptor cones in the terrapin and modeled their sensitivity in the UV, blue, green and red portions of the electromagnetic spectrum (~355-640 nm), conferring tetrachromatic visual ability. Terrapins exhibited unusual absorbance of light in the ocular media, resulting in unusual spectral tuning of photoreceptor sensitivities. I measured the light environment in the water column at the surface and at half-meter intervals below the surface. The downwelling irradiant light environment at the surface of the water column spectrally matched the visual sensitivity modeled here in the terrapin, resulting in optimal photon capture. I measured spectral reflectance of ten distinct color patches on the terrapin which also spectrally matched modeled sensitivities and surface downwelling light, resulting in optimal perception of conspecific coloration at the surface of the water column. Five color patches were measured on the skin and five on the shell. Skin color patches exhibited a clear UV and longwave components, while the shell only exhibited a longwave component. Hatchling paternity results suggested that females potentially preferred males with higher color contrast between the shell and the skin, as well as greater hue saturation of the shell. Although the number of genotype-matched fathers was low (N = 14), this study suggests that non-random mating may be occurring in the Barnegat Bay, NJ terrapin population.Ph.D., Environmental Science -- Drexel University, 201