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It is the responsibility of pavement engineers to design pavements that provide safe and smooth riding surfaces over their entire life cycle. Each year many people around the world lose their lives in vehicle crashes, which are one of the leading causes of death in the United States (US). One of the contributing factors in many of these crashes is inappropriate friction between tires and the pavement. To minimize the impact of this factor, state Departments of Transportation (DOTs) must monitor the friction of their pavement networks systematically and regularly. Several devices are used around the world for measuring friction. Locked-wheel skid trailers are the predominant technology for roadways in the U.S. However, Continues Friction Measuring Equipment (CFME) is emerging as a practical alternative, especially for network-level monitoring. This type of technology has been used for monitoring runway friction for many years and is starting to be used also for measuring roadway friction. This thesis evaluates the different operational characteristics of CFME to provide guidelines for highway agencies interested in using this technology for supporting their friction management programs. It follows a manuscript format and is composed of two papers. The first part of the thesis presents a methodology to objectively synchronize and compare CFME measurements using cross-correlation. This methodology allows for comparing the “shape” of the friction profiles, instead of only the average friction values. The methodology is used for synchronizing friction measurements and assessing the repeatability and reproducibility of the CFME using friction measurements taken on a wide range of surfaces at the Virginia Smart Road. The proposed approach provides highway agencies with a rigorous method to process CFME measurements. The second part of the thesis evaluates the impact of several operational characteristics on the CFME measurements using a field experiment. The results of the experiment confirmed that the measurements are significantly affected by (1) the direction of testing while testing on sections of road with a significant grade, (2) water film thickness, and (3) testing speed. The experiment showed that measurements taken downhill on a 6% grade were significantly higher than those taken uphill. The analysis also verified that, consistent with previous studies, the measured friction decreases with higher water depth and testing speeds. It also showed that the change of friction with speed is approximately linear over the range of speeds used in the experiment. In general, the thesis results suggest that CFME can provide repeatable and reproducible friction profiles that can be used to support friction management programs and other asset management business functions. However, care should be taken with regard to the operational conditions during testing since the measurements are affected by several factors. Further research is needed to (1) quantify the effect of these, and potentially other, operational factors; and (2) establish standard testing condition and approaches for correcting measurements taken under other conditions. / Master of Science

No / To evaluate repeatability and reproducibility of macular thickness measurements in visually normal eyes using the Topcon 3D OCT-1000. Methods: Phase 1 investigated scan repeatability, the effect of age and pupil dilation. Two groups (6 younger and 6 older participants) had one eye scanned 5 times pre and post- dilation by 1 operator. Phase 2 investigated between-operator, within and between-visit reproducibility. 10 participants had 1 un-dilated eye scanned 3 times on 2 separate visits by 2 operators. Results: Phase 1: No significant difference existed between repeat scans (p=0.75) and no significant difference was found pre- and post-dilation (p=0.54). In the younger group variation was low (95% limits ± 3.62 m) and comparable across all retinal regions. The older group demonstrated greater variation (95% limits ± 7.6 m). Phase 2: For a given retinal location, 95% confidence limits for within-operator, within-visit reproducibility was 5.16 m. This value increased to 5.56 m for the same operator over two visits and to 6.18 m for two operators over two visits. Conclusion: A high level repeatability, close to 6 m, of macular thickness measurement is possible using the 3D OCT- 1000. Measured differences in macular thickness between successive visits that exceed 6 m in pre-presbyopic individuals are therefore likely to reflect actual structural change. OCT measures are more variable in older individuals and it is advisable to take a series of scans so that outliers can be more easily identified.

Dual Energy X-ray Absorptiometry (DXA)-based finite element (FE) modelling has emerged as a potential tool for better assessment of osteoporotic hip fracture risk. Automation of this complex and computationally-intense procedure is the prime requirement for its clinical applicability. The aim of this study was to develop a fully automatic DXA-based finite element tool and assess its discrimination ability and short-term repeatability. The proximal femur was automatically segmented from clinical hip DXA scan and the subject-specific FE model was constructed for simulating sideways fall. Hip fracture risk indices (HFRIs) were calculated using two ways (along a femur cross-section and over a region of interest, ROI). Hip fracture discriminability increased when moved from femur cross-section based to ROI based HFRI calculation. A significant increase in hip fracture discriminability from baseline femoral neck and total hip bone mineral density (BMD) was achieved with ROI based HFRIs. Promising short-term repeatability was observed for HFRIs (coefficient of variation, CV, 3~3.5%). After removing representative poor cases, CVs were less than 3%. These preliminary results establish the potential of the proposed automatic tool for hip fracture risk assessment and justify large-scale clinical evaluation of its ability to predict incident hip fractures. / February 2017

Submitted by (ana.araujo@ufrpe.br) on 2017-02-16T16:47:59Z No. of bitstreams: 1 Hudsonkleio da Costa Silva.pdf: 1360315 bytes, checksum: 496e932ecdd318656c26fc4681553375 (MD5) / Made available in DSpace on 2017-02-16T16:48:00Z (GMT). No. of bitstreams: 1 Hudsonkleio da Costa Silva.pdf: 1360315 bytes, checksum: 496e932ecdd318656c26fc4681553375 (MD5) Previous issue date: 2012-06-28 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The sugarcane (Saccharum spp.) presents itself as a culture of great social and economic importance for Brazil. The breeding programs have contributed to increasing productivity in sugarcane areas of the country, due to the replacement and renewal of sugarcane, this increase amounted to thirty percent increases in the last three decades. However, the efficiency of the breeding programs of sugarcane depends on the spatial and temporal repeatability of traits under selection. Thus, assessment surveys genotype x environment interaction and repeatability of characters is crucial to the selection result in success. The objective of this study was to evaluate the behavior of agroindustrial genotypes sugarcane in all three cutting times and reliably determine the number of evaluations needed to select new genotypes based on their production components. The experiments were conducted: in Santa Teresa Mill (Goiana) in the years 2006/2007, 2007/2008, 2008/2009, evaluating 25 genotypes; in São José Mill (Igarassú) in the years 2005/2006, 2006/2007, 2007 / 2008 and 2008/2009, to evaluate the repeatability of characters in 16 genotypes, located on the northern coast of Pernambuco, both in a randomized block design, with plots consisting of five eight-meter grooves and spaced one meter. In each section were measured variables: ton of pol per hectare (TPH), ton of cane per hectare (TCH) pol in cane corrected (PCC), fiber (FIB), purity (PZA), soluble solids (° BRIX ) and total recoverable sugar (TRS). Data were subjected to analysis of variance, the group averages by testing Skott & Knott and repeatability of the experiment than those we used: ANAVA, principal component analysis (variance and covariance) and structural analysis. Based on the results of gross income, the best genotypes for beginning and middle of harvest were RB86 7515, RB92 579 and SP81 3250, to end of season highlight for genotypes RB86 7515, SP78 4764 and SP81 3250. To select new genotypes based on the coefficient of repeatability, methods of structural analysis and principal components were equivalent, and depending on the variable in the analysis and reliability stipulated, the number of assessments varied: for TPH and TCH were needed for reliability of 2 reviews 90% for FIB, PCC, PZA, BRIX and ATR were 3-4 consecutive assessments. / A cana-de-açúcar (Saccharum spp.) apresenta-se como uma cultura de grande importância social e econômica para o Brasil. Os programas de melhoramento genético vêm contribuindo para o aumento da produtividade nas áreas canavieiras do país, graças à substituição e renovação dos canaviais, esse incremento atingiu aumentos de trinta por cento nas três últimas décadas. No entanto, a eficácia dos programas de melhoramento de cana-de-açúcar depende da repetibilidade espacial e temporal dos caracteres sob seleção. Com isso, pesquisas de avaliação de interação genótipo x ambiente e repetibilidade de caracteres é de fundamental importância para a seleção resultar em sucesso. Objetivou-se com esse trabalho avaliar o comportamento agroindustrial de genótipos de cana-de-açúcar nas três épocas de corte e determinar com confiabilidade o número de avaliações necessárias para selecionar novos genótipos baseado em seus componentes de produção. Os experimentos foram instalados: na Usina Santa Teresa (Goiana) nos anos agrícolas 2006/2007, 2007/2008, 2008/2009, avaliando 25 genótipos; na Usina São José (Igarassú) nos anos agrícolas 2005/2006, 2006/2007, 2007/2008 e 2008/2009, avaliando-se a repetibilidade de caracteres em 16 genótipos, localizados no Litoral Norte de Pernambuco, ambos em delineamento experimental de blocos casualizados, com parcelas composta de cinco sulcos de oito metros e espaçadas de um metro. Em cada corte foram mensuradas as variáveis: tonelada de pol por hectare (TPH), tonelada de cana por hectare (TCH), pol na cana corrigido (PCC), fibra (FIB), pureza (PZA), teor de sólidos solúveis (ºBRIX) e açúcar total recuperável (ATR). Os dados foram submetidos à análise de variância conjunta, o agrupamento de médias através do teste de Skott & Knott e para o experimento de repetibilidade além desses utilizou-se: ANAVA, análise de componentes principais (variância e covariância) e análise estrutural. Com base nos resultados obtidos de renda bruta, os melhores genótipos para início e meio de safra foram RB867515, RB92579 e SP813250; para final de safra destaque para os genótipos RB867515, SP784764 e SP813250. Para selecionar novos genótipos baseado no coeficiente de repetibilidade, os métodos de componentes principais e análise estrutural se equivaleram, sendo que dependendo da variável em análise e da confiabilidade estipulada, o número de avaliações variou: para TPH e TCH foram necessárias 2 avaliações para confiabilidade de 90%, para FIB, PCC, PZA, BRIX e ATR foram de 3 a 4 avaliações consecutivas.

Para muitos componentes e estruturas de engenharia a determinação precisa do estado de tensões residuais presente é de fundamental importância para a avaliação de sua integridade estrutural. O método do furo cego (MFC) é um dos métodos mais difundidos para a medição de tensões residuais, no entanto, por se tratar de um ensaio relativamente complexo, a determinação da sua incerteza de medição apresenta uma série de dificuldades, as quais se refletem na inexistência de estudos na literatura que abordem esse assunto de forma completa. Este trabalho tem como objetivo a determinação da incerteza de medição do MFC englobando todas as fontes de incerteza em potencial do método. Para tanto, foi elaborado um procedimento envolvendo a determinação e caracterização das fontes de incerteza tanto na parte experimental como no tratamento matemático dos dados. A partir da caracterização das fontes de incerteza detectou-se como fator principal na determinação da incerteza o erro do operador, que foi possível através do desvio de repetitividade. A fonte de incerteza devido ao erro do operador foi a de determinação mais complexa e envolveu o projeto e a construção de uma máquina especialmente desenvolvida para a aplicação de um estado de tensões homogêneo e que permitisse medir com precisão as tensões residuais com o método do furo cego. Técnicas de medição de tensões residuais por difração de raios-X e monitoramento de tensão com extensometria de resistência elétrica foram utilizadas para a verificação da homogeneidade das tensões nas amostras. A metodologia se mostrou adequada, conduzindo a resultados que permitiram determinar com sucesso a incerteza de medição através de planilhas eletrônicas. / The characterization of the residual stress state of engineering components and structures is of fundamental importance for assessments of their structural integrity. The hole drilling method is one of the most commonly used methods; however, due to its relative complexity, quantifying its measurement uncertainties is not straightforward. It is a semi-destructive method, which means that multiple measurements cannot be repeated in a same location, and stress distributions mean that it is difficult to guarantee that a number of points in the same state will be available in a given volume. This study suggests a global uncertainty measurement which includes a study of repeatability related to the operator. This is thought to be novel in the existing literature. For this, a standard sample and a machine which guarantees a homogeneous stress distribution in the sample were developed. To ensure the homogeneity of the stresses, x-ray diffraction measurements were performed. The results obtained show good repeatability for different operators and good results for the uncertainty of measurements for the method.

The human foot is a biomechanical marvel which forms the distal link in the lower limb kinematic chain. With its small polyarticular construct and flexibility, it supports the body and provides balance during walking. The first metatarsophalangeal joint (MTPJ) is a vital joint in the forefoot for normal load transmission and energy efficient locomotion. Albeit a lot in literature about this joint, paucity still exists in the biomechanical aspects. Also, there is a speculation in the biomechanical world that the time integral component of pressure recorded from the plantar pressure measuring devices maybe representative of the shear force recorded from force platforms. The aim of the current study was to quantify the kinematics of the first MTPJ in three dimensions and the pedobarographic data under the first MTPJ during each sub-phase of stance in the gait cycle of normal subjects and to assess the correlation between the shear force from the force plate of the motion capture system with the variables from the barefoot plantar pressure measuring device. Similar quantification will be undertaken for the patients with isolated hallux rigidus. After obtaining ethical approval, 40 normal subjects (80 feet) and 6 patients with varying grades of hallux rigidus were recruited for the study. The equipment used to collect data included the Vicon® motion analysis system, AMTI® force plate and the emed® plantar pressure measuring device. Various checks were performed to establish the reliability of the system setup. Four trials from each foot were taken. Of the 320 total trials from the normal subjects, the trial numbers varied for specific tasks as some trials which were suitable for testing one objective might not be suitable for testing the other. One of the patients’ data could not be used as the data quality was below par due to issues with marker tracking. The correlation between the shear force from the force plate and the anthropometric measurements/parameters from the plantar pressure measuring device was performed using the statistical regression model. The Vicon® data of the whole stance phase revealed that the first MTPJ’s sagittal plane motion ranged from 9° of plantarflexion to 53° of dorsiflexion. In the coronal plane, the maximum pronation was 34° and supination was 31°. In the transverse plane, the maximum varus was 11° and the valgus was 24°. There were two dorsiflexion peaks; one at the Initial contact and the other at Pre-swing. The joint moved from supination to pronation and varus to valgus during the progression of stance phase from Initial contact to Pre-swing. Considering the emed®-m, there were four basic parameters namely the force, area, peak pressure and maximum mean pressure from which the other parameters were derived. Only the basic parameters accounted for the sub-phases of stance and it came to light that the force under the first MTPJ was maximum in the terminal stance (22.1%). For the whole stance phase, the first MTPJ contributed about 11% of the contact area, 14.5% of the mean area, 24% of the maximum force, 56% of the peak pressure, 63% of maximum mean pressure, 44% of Pressure-time integral, 14% of Force-time integral and 14% of mean force. The correlation equation with reasonable number of dependent variables obtained by the statistical regression model could account for only 46% of the shear force. Among the paired correlation equations with single dependent variable, the one with the mean force was the best and even this could only account for 31.1% of the shear force. Albeit 3 patients were having similar radiological grading of the pathology and 2 others falling into another grade, their objective data were diverse and couldn’t be grouped together. The normal kinematics of the first MTPJ and the pedobarographic data under the first MTPJ were quantified during each subphase of stance. Attempt to use one system alone instead of two to calculate the shear force did not provide satisfactory results. The patients’ data questions the use of radiology alone in deciding the management plan which is a common scenario in the current clinical setting.

Developments in micro and nano technology have great potential in many applications. Two applications that will be addressed in this work are self assembly of microdevices and Electrowetting in microfluidics. Capillary forces are the most critical factor in both of these techniques and need proper characterization. This thesis describes a detailed study of these forces and explains how they were utilized as an effective source of drive in high end applications. Self assembly is a promising alternative to conventional pick and place robotic assembly of micro components. Its benefits include parallel integration of parts with low equipment costs. Various approaches to self assembly have been demonstrated, yet demanding applications like assembly of micro-optical devices require increased positioning accuracy. This thesis proposes a new method for design of self assembly bonds that addresses this need. Current methods have zero force at the desired assembly position and low stiffness. The proposed method uses a substrate assembly feature to provide a high accuracy alignment guide to the part. The capillary bond region of the part and substrate are then modified to create a non-zero positioning force to maintain the part in the desired assembly position. Capillary force models show that this force aligns the part to the substrate assembly feature and reduces the sensitivity of part position to process variation. Thus, the new configuration analyzed proves substantial improvement in positioning accuracy of capillary self assembly. Guidelines are proposed for the design of an effective assembly bond using this new approach. Electrowetting is another application that has been successfully demonstrated as a means of drop manipulations in digital micro-fluidic devices. These demonstrations show that electrowetting actuation holds great promise, but there are also reports of erratic behavior and system degradation. While a method for electrowetting force measurement to track the degradation of the electrowetting response was demonstrated, this thesis analyzes some adverse effects in the electrowetting response due to variations during measurement of electrowetting forces, specially the variation of volume, the tilt in the part considered for measurements, and defective layer response.

Roughness is an important indicator of pavement riding comfort and safety. It is a condition indicator that should be carefully considered when evaluating primary pavements. At the same time, the use of roughness measurements plays a critical role in the pavement management system. There are many devices used for roughness evaluation. The major tools used for road roughness quantify are the road profilers. In the thesis research, in order to obtain useful pavement surface condition data for pavement evaluation, two direct type road roughness evaluation systems were developed with the combination of modern sensor technology and computer technology. The thesis will focus on the development of the direct type profiler systems, including the improvement of the hardware design, the new direct type road roughness-measuring system using different method, the software development, which makes it more functional. In order to evaluate the accuracy and correction of the direct type profiler system, different roughness devices (including FDOT High-Speed laser profiler, FACE Dipstick and direct type I profiler) were operated in 4 calibration sites. The research focused on several performance measures, such as correlativity, repeatability. IRI and RN results from these devices were analyzed to evaluate the correlativity between these devices. After verified that direct type I profiler has good repeatability and correlation with FDOT High-Speed laser profiler, FACE Dipstick, 10 calibration sites data in Tampa were collected using direct type I profiler and direct type II profiler. The repeatability and correlation analysis between the two profilers were performed. From field experiments and data analysis, it shows: 1.Direct type I profiler showed satisfactory repeatability performances; 2.Direct type I profiler has good RN correlations High-Speed laser profiler; 3.Direct type I profiler has good correlations with Dipstick, High-Speed laser profiler in terms of IRI 4.Direct type II profiler does not has good correlation with direct type I profiler; the performance needs to be improved. Except for these conclusions, it is also found that the High-Speed profiler can be operated at different speeds with little differences in RN values, the sampling rate did show impact on RN value.

This thesis presents a novel three dimensional (3D) image-analysis method for characterizing the physical characteristics of coarse particles in the field, and introduces new methodology for the total analysis of glacial till samples. The novel image analysis method, called the GID method, is capable of determining the size, shape and surface texture of each individual clast analysed. Images of particles are taken in the field and analysis is done in the laboratory. Therefore the GID method makes it feasible to analyse statistically representative large sample in short period; for poorly sorted sediments, such as till, one-tonne is required if the analysis includes cobble size. The capability of the GID method was demonstrated by studying coarse clasts (20-200 mm) from till. There is excellent agreement in the results of the size distribution obtained from the GID method and sieve analysis. The GID method results for size and shape parameters show high and very high repeatability. The particle angularity in the GID method has not been measured to acceptable level; the repeatability test shows some variability. The new methodology for total analysis of till applied the GID method at four different locations in Sweden. The total analysis included 3D size and shape distribution of coarse particles coupled to electrical resistivity, lithological distribution and magnetic susceptibility of the clasts. The results show clear difference in the till samples from the different sites. / <p>QC 20120828</p>