O presente estudo avaliou in vitro a influência de diferentes tipos de enxaguatórios bucais associados com a escovação, na alteração de cor e rugosidade superficial de diferentes tipos de resinas compostas diretas (M1- Filtek Supreme XT, M2- Z100, M3- Ice) por meio do espectrocolorímetro PCB 6807 da BYK-Gradner, rugosímetro modelo SJ-201P Mitutoyo e Microscopia Eletrônica de Varredura. Foram preparados 300 corpos de prova (n=10) para a variável alteração de cor, e destes espécimes 180 (n=6) foram submetidos ao ensaio de rugosidade superficial. Os espécimes foram polidos com discos Soft Lex, na sequência de abrasividade decrescente e armazenados em saliva artificial a 37°(±1°C) até o momento de serem submetidos nas soluções S1- Solução com álcool e com corante, Colgate Plax Fresh Mint; S2- Solução sem álcool e com corante, Oral-B; S3- Solução com álcool e sem corante, Cepacol; S4- Solução sem álcool e sem corante, Colgate Plax e S5- Grupo controle, Saliva Artificial e realização das leituras das variáveis em estudo, nos tempos T0- imediatamente após o polimento, T1- 7dias, T2- 14dias, e T3- 21dias. Todos os espécimes dos grupos experimentais foram imersos sob agitação, nos diferentes enxaguatórios bucais, 1 vez ao dia, por 2 minutos, durante 5 dias na semana. Após a realização de todas as leituras do estudo foram selecionados dois espécimes de maneira aleatória, de cada grupo experimental, totalizando 30 espécimes que foram submetidos a observação por médio de Microscopia Eletrônica de Varredura. Os dados de alteração de cor e de rugosidade superficial para cada uma das resinas, individualmente e para comparação das três resinas submetidas à escovação foram analisados por meio do teste ANOVA e Tukey (p≤0,05). Os resultados para alteracao de cor mostraram que: o fator Solução foi significante somente para a resina Filtek Supreme XT, sendo a menor média S1 e a maior S3, por outro lado S2, S3, S4 e S5 foram estatisticamente iguais. O fator tratamento escovação foi significante para as resinas M2 e M3, sendo que para M2 a condição CES determinou maior média que SES e para M3, SES foi maior que CES. Para as três resinas o fator Tempo foi estatisticamente significante: a) M1 no T1 a média foi menor que em T2 e T3; b) para M2 a média em T1 foi menor que T2 e maior que T3; c) em M3, T1 foi igual a T2 que por sua vez foram menores que T3. Comparando o comportamento das três resinas constatou-se que M1 e M3 tiveram medias estatisticamente iguais e maiores que M2. Com relação à rugosidade superficial dos materiais M2 e M3, submetidos aos enxaguatórios utilizados neste estudo verificou-se que este fator não teve efeito estatisticamente significante; enquanto que para M1 houve diferença significante, assim, as médias de S1, S2 e S3 foram iguais e menores que as médias de S4 e S5. O fator tratamento escovação teve efeito significante somente para M1 sendo que a condição SES apresentou maior media que a CES. Com relação ao fator tempo verificou-se que para M1, a partir de T1, T2 e T3 as medias foram iguais entre si e maiores que T0; para M2 a maior media foi em T2 havendo igualdade estatística entre T0, T1 e T3; já para M3 as medias em T2 e T3 foram estatisticamente iguais e maiores que T0. Comparando as três resinas M1 apresentou maior rugosidade que M2 e M3 que foram estatisticamente iguais entre si. De acordo com a metodologia utilizada conclui-se que a alteração de cor das resinas estudadas foi influenciada pelo tempo; o tratamento escovação determinou alteração de cor para M2 e M3 e não foram influenciadas pelas soluções em estudo; M2 apresentou menor alteração que M1 e M3. Para rugosidade superficial conclui-se que o fator solução e o fator tratamento foram significantes somente para M1. O fator tempo influenciou a rugosidade das três resinas compostas. Relevância clinica: Há necessidade que o cirurgião dentista conheça as características das resinas compostas a ser utilizada no tratamento restaurador, além dos prováveis efeitos que os enxaguatórios bucais possam ter nas propriedades físicas do material, para assim indicá-los corretamente. / The present study evaluated in vitro the influence of different types of mouthwash associated with brushing, the color change and surface roughness of different types of direct composite resins (M1 - Filtek Supreme XT, M2 - Z100, M3 - Ice) through a PCB 6807 spectrocolorimeter of BYK-Gradner, rugosimeter model Mitutoyo SJ-201P and scanning electron microscopy. 300 specimens (n = 10) for the color alteration variable were prepared; of these, 180 specimens (n = 6) were subjected to tests surface roughness. The specimens were polished with discs Soft Lex (3M), following the decreasing abrasiveness sequence and stored in artificial saliva at 37 ° (±1 ° C) until be submitted in solutions S1 - solution with alcohol and dye, Colgate Plax Fresh Mint; S2 - solution without alcohol and with dye, Oral-B; S3 -solution with alcohol and without dye, Cepacol, S4 - Solution without alcohol and dye, Colgate Plax; S5 - Control Group, Artificial Saliva. The readings of the variables in study occurred in T0 - immediately after polishing, T1 7 days after, T2 14 days after and T3 21 days after. All specimens of the experimental groups were immersed with agitation in the different mouthrinses, once a day, for 2 minutes, during 5 days per week. After performing all readings of the study, two randomly selected specimens were chose from each experimental group, a total of 30 specimens were selected randomly and subjected to observation by scanning electronic microscopy. The data on color change and surface roughness for each resin were analyzed separately and together for comparison across the tests ANOVA and Turkey (p ≤ 0.05). The results for color change demonstrated that the factor solution was significant only for Filtek Supreme XT resin, with S1 being the smallest and S3 the largest average. Still, S2, S3, S4 and S5 were statistically equal. The brushing treatment factor was significant for M2 and M3 resins, as the CES (with brushing) condition had a higher average than the SES (without brushing) one for M2; and for M3, SES was higher than CES. For the three resins, the time factor was significant: a) M1 at T1, the average was lower than in T2 and T3, b) to the M2 medium was lower than in T1 and T2 greater than T3, c) in M3, t1 was equal to t2 and both lower than T3. Comparing the behavior of the three resins, it was found that M1 and M3 average were statistically equal and higher than M2. Regarding the surface roughness of materials M2 and M3, submitted to rinses utilized in this study it was found that this factor had no statistically significant effect, while for M1 was significant difference, with the average of S1, S2 and S3 were equal and lower than the averages of S4 and S5. The factor brushing treatment effect was significant only for M1 being that the condition SES had a higher rating than the CES. Regarding the time factor, it was found that for M1, from T1, T2 and T3, the average was equal and higher than T0, for M2, the higher average was in T2, with statistical equality among T0, T1 and T3; for M3 average in T2 and T3 were statistically equal and greater than T0. Comparing the three resins, M1 showed higher roughness than M2 and M3 who were statistically equal. According to the used methodology, concludes that the color change of the resins was influenced by the time; treatment brushing determinate the color change for M2 and M3 and both were not influenced by the solutions under study; M2 showed lowest change than M1 and M3. For surface roughness is concluded that the factor solution and factor treatment were significant only for M1. The time factor influenced the roughness of the three composite resins. Clinical Relevance: It is necessary that dental surgeon know the characteristics of composite resins to be used in restorative treatment, beyond the likely effects that the mouthrinses may have on the physical properties of the material, to have correct indications.

O objetivo deste trabalho foi identificar a influência das condições de usinagem sobre o acabamento superficial no faceamento de uma liga de alumínio com ferramenta de diamante. Os parâmetros de corte variados foram: velocidade de corte, avanço e profundidade de corte. De acordo com a bibliografia consultada apenas o avanço e o raio de ponta da ferramenta afetam diretamente o acabamento superficial, sendo que quanto menor o avanço e maior o raio de ponta melhor será o resultado em termos de rugosidade superficial. A profundidade de corte é dita apenas influenciar na força de corte e não no acabamento. Outro parâmetro de corte que segundo a bibliografia não apresenta influência seria a velocidade de corte, sendo que sua variação não afeta os resultados de acabamento superficial. Os ensaios demonstraram que dentre as condições de corte estudadas o avanço é o parâmetro de maior influência, com os menores valores de rugosidade obtidos para um avanço de 2 &#956m/rev. A profundidade de corte apresentou pouca influência no acabamento, apresentando um efeito previsto pela literatura, o \"size effect\", a uma profundidade de corte de 3 &#956m, e a velocidade de corte não apresentou influência. A liga de alumínio testada foi a 7075-T6. Utilizou-se uma ferramenta de diamante monocristalino nova com raio de ponta de 1.524 mm e ângulos de folga e de saída de 11º e 0º, respectivamente. / The objective of this work was to identify the influence of the cutting conditions on surface roughness of an aluminum alloy faced with a single-point diamond tool. The cutting parameters to be varied were: feedrate, depth of cut and cutting speed. According to the literature, only the feedrate and the tool nose radius have direct influence on surface roughness, in the following way: The lower the feedrate and the greater the nose radius, the better the surface roughness. The depth of cut is said only to influence on the cutting forces and do not affect the surface roughness. The cutting speed also has no influence on surface roughness, according to the literature. Experimental investigation has demonstrated that, among the tested cutting conditions, the feedrate has the most influence with low values of surface roughness obtained at a feedrate of 2 &#956m/rev. The depth of cut has very little influence on the surface finish. lt just showed an effect foreseen by the literature, the size effect, at a depth of cut of 3 &#956m and the cutting speed has not showed any influence. The aluminum alloy investigated was 7075-T6. A fresh diamond tool was used, with a nose radius of 1.524 mm and 11º and 0º clearance and rake angle, respectively.

O clareamento dental é o meio disponível mais simples, comum e conservador para o cirurgião-dentista proporcionar aos pacientes o padrão de cor de seus dentes mais desejado. Em alguns casos, os dentes que vão ser clareados podem apresentar restaurações realizadas com compósitos dentais, que são mais suscetíveis a alterações químicas, quando comparados a outros materiais restauradores. Alguns estudos mostraram que diferentes concentrações de agentes clareadores levaram a um aumento significativo da rugosidade superficial e das porosidades em compósitos dentais. Este estudo avaliou o efeito de dois agentes clareadores (Whiteness HP Blue 20%, Whiteness HP Max) sobre a rugosidade superficial de dois compósitos dentais, um micro-híbrido (Esthet X, Denstply) e outro nanoparticulado (Z 350, 3M ESPE). Um total de oito corpos de prova (9 x 2 mm) foram confeccionados com auxílio de uma matriz de teflon, sendo divididos em 4 grupos (Esthet X + Whiteness HP Blue 20%; Esthet X + Whiteness HP Max; Z 350 + Whiteness HP Blue 20%; Z 350 + Whiteness HP Max), sendo n=2. Os corpos de prova foram armazenados em saliva artificial neutra e, após 24 horas, foram polidos com discos de óxido de Alumínio (Sof-lex, 3M ESPE). Após sete dias de imersão salivar, cada corpo de prova foi levado a um microscópio de força atômica para obtenção do valor inicial de rugosidade superficial (Ra em nm). Em seguida, sem remover o corpo de prova do microscópio, o agente clareador foi aplicado sobre a superfície do corpo de prova, segundo as instruções do fabricante, de modo que permitisse uma posterior observação da mesma área do corpo de prova observada inicialmente, para obtenção do valor final de rugosidade superficial. Imagens em duas e três dimensões foram obtidas de cada corpo de prova para observação de alterações da topografia. Os resultados foram tratados estatisticamente por ANOVA e pelo teste de contraste Student-Newman-Keuls (p < 0,05). Não houve alteração significativa na rugosidade superficial (Ra) dos corpos da prova de compósitos micro-híbrido e nanoparticulado, submetidos aos agentes clareadores Whiteness HP Blue 20% e Whiteness HP Maxx. No entanto, independente do agente clareador utilizado, foram observadas maiores alterações topográficas nas imagens de microscopia de força atômica da superfície do compósito micro-híbrido do que nas imagens do nanoparticulado. / Dental bleaching is the simplest, the most common and conservative available way for dentists to offer their patients the standard color of teeth more desired. In some cases, the teeth that will be bleached may include restorations made of resin composites, which are more prone to chemical alteration compared with other restoration materials. Some studies have showed that different concentrations of bleaching gels might lead to a significant increase in surface roughness and amount of porosities in composite resins. This study evaluated the effect of two bleaching gels (Whiteness HP Blue 20%, Whiteness HP Max) on surface roughness of two resin composites, micro-hybrid (Esthet X, Denstply) and nanoparticled (Z350, 3M ESPE). A total of eight specimens (9 x 2 mm) were produced with a Teflon mold help, and were divided into four groups (Esthet X + Whiteness HP Blue 20%; Esthet X + Whiteness HP Max; Z 350 + Whiteness HP Blue 20%; Z 350 + Whiteness HP Max), with n=2. They were stored in neutral artificial saliva and, after 24 hours, were polished with aluminium oxide discs (Sof-lex, 3M ESPE). After seven days of salivary immersion, each specimen was taken to an atomic force microscope for recording initial value of surface roughness (Ra in nm). After that procedure, without removing the specimen from microscope, the bleaching gel was applied on the surface of the specimen, following manufacturers instructions, in order to allow posterior observation of the same area of the specimen initially observed, for recording the final value of surface roughness. Two-dimensional and 3D images were taken from each specimen group for observation of surface alterations. The results were statistically analyzed by ANOVA and the SNK test (p< 0.05). There were no statistically significant differences in the surface roughness (Ra) for specimens of micro-hybrid and nanoparticled composites, submitted to the bleaching agents Whiteness HP Blue 20% and Whiteness HP Maxx. However, there were noticed larger surface alterations in atomic force microscope images on the surface of micro-hybrid composites than on the nanoparticled, independently of the bleaching agent used.

O objetivo deste trabalho foi identificar a influência das condições de usinagem sobre o acabamento superficial no faceamento de uma liga de alumínio com ferramenta de diamante. Os parâmetros de corte variados foram: velocidade de corte, avanço e profundidade de corte. De acordo com a bibliografia consultada apenas o avanço e o raio de ponta da ferramenta afetam diretamente o acabamento superficial, sendo que quanto menor o avanço e maior o raio de ponta melhor será o resultado em termos de rugosidade superficial. A profundidade de corte é dita apenas influenciar na força de corte e não no acabamento. Outro parâmetro de corte que segundo a bibliografia não apresenta influência seria a velocidade de corte, sendo que sua variação não afeta os resultados de acabamento superficial. Os ensaios demonstraram que dentre as condições de corte estudadas o avanço é o parâmetro de maior influência, com os menores valores de rugosidade obtidos para um avanço de 2 &#956m/rev. A profundidade de corte apresentou pouca influência no acabamento, apresentando um efeito previsto pela literatura, o \"size effect\", a uma profundidade de corte de 3 &#956m, e a velocidade de corte não apresentou influência. A liga de alumínio testada foi a 7075-T6. Utilizou-se uma ferramenta de diamante monocristalino nova com raio de ponta de 1.524 mm e ângulos de folga e de saída de 11º e 0º, respectivamente. / The objective of this work was to identify the influence of the cutting conditions on surface roughness of an aluminum alloy faced with a single-point diamond tool. The cutting parameters to be varied were: feedrate, depth of cut and cutting speed. According to the literature, only the feedrate and the tool nose radius have direct influence on surface roughness, in the following way: The lower the feedrate and the greater the nose radius, the better the surface roughness. The depth of cut is said only to influence on the cutting forces and do not affect the surface roughness. The cutting speed also has no influence on surface roughness, according to the literature. Experimental investigation has demonstrated that, among the tested cutting conditions, the feedrate has the most influence with low values of surface roughness obtained at a feedrate of 2 &#956m/rev. The depth of cut has very little influence on the surface finish. lt just showed an effect foreseen by the literature, the size effect, at a depth of cut of 3 &#956m and the cutting speed has not showed any influence. The aluminum alloy investigated was 7075-T6. A fresh diamond tool was used, with a nose radius of 1.524 mm and 11º and 0º clearance and rake angle, respectively.

O objetivo desse estudo foi avaliar sistematicamente o efeito da escovação simulada e do envelhecimento artificial acelerado (EAA) sobre estabilidade de cor e rugosidade de superfície de compósitos odontológicos de nanopartículas (Z350 - 3M ESPE) e híbrido (Tetric N-Ceram - Ivoclar Vivadent). Foram confeccionados 24 corpos-de-prova (12mm de diâmetro X 2mm de espessura) para cada compósito e uma cerâmica de revestimento (IPS e.max Ceram - Ivoclar Vivadent) como controle. Após sua confecção, os corpos-de-prova foram polidos com lixas d&lsquo;água em abrasividades decrescentes (compósitos = 600, 1200 e 2000 e cerâmica = 100, 320, 1200 e 2000). Em seguida, foram realizadas leituras iniciais de cor (Espectrofotômetro PCB 6807) e rugosidade de superfície (Rugosímetro Surfcorder SE 1700 - Kosakalab). As amostras foram separadas em 3 grupos (n=8), segundo o tratamento a que foram submetidas: Grupo 1: EAA; Grupo 2: escovação mecânica com dentifrício RDA* 68 (Colgate); e Grupo 3: escovação mecânica com dentifrício RDA* 180 (Colgate Total Plus Whitening). Após 480 horas de EAA e em intervalos de 41 minutos de escovação (=14.600 ciclos) até 205 minutos novas leituras de cor e rugosidade de superfície foram realizadas. Amostras inicialmente submetidas a EAA (n=4) receberam escovação mecânica com dentifrício RDA* 68 e 180, conforme metodologia descrita anteriormente e novas leituras de cor e rugosidade foram obtidas. Os dados (antes e após os testes) foram analisados estatisticamente (2-way ANOVA análises repetidas, Bonferroni, p<0,05) e verificou-se que houve maior alteração de cor dos compósitos quando submetidos a EAA com diferença estatisticamente significante (p<0,05) em relação à escovação mecânica. Não houve diferença estatisticamente significante (p>0,05) na estabilidade de cor dos materiais quando comparadas as abrasividades dos dentifrícios, porém esse fator foi significante para a alteração de rugosidade de superfície (p<0,05), sendo maior quando os materiais foram escovados com RDA* 180. Quanto ao tempo de escovação, não houve diferença estatisticamente significante (p>0,05) para a alteração de cor e de rugosidade de superfície dos materiais, o mesmo ocorrendo para amostras escovadas após EAA. Conclui-se que o EAA interfere na estabilidade de cor e a escovação simulada nas alterações de rugosidade de superfície dos compósitos, independente do tempo de utilização do dentifrício, sendo maior para dentifrícios mais abrasivos. Além disso, a abrasividade e o tempo de utilização do dentifrício não alteram a capacidade de remoção do manchamento e a rugosidade de superfície de compósitos. / The purpose of this study was to evaluate the effect of simulated toothbrushing and accelerated artificial aging (AAA) on color stability and surface roughness of nanofill (Z350 - 3M ESPE) and hybrid (Tetric N-Ceram - Ivoclar Vivadent) composites. Twenty-four diskshaped specimens (12mm in diameter X 2 mm thick) were made for each composite and one feldspatic ceramic (IPS e.max Ceram - Ivoclar Vivadent) as a control. The specimens were polished with decreasing abrasiveness sandpapers (composites = 600, 1200, 2000 and ceramic = 100, 320, 1200, 2000). Then, initial readings were taken on color (Spectrophotometer PCB 6807) and surface roughness (Rugosimeter Surfcorder SE 1700 - Kosakalab). The samples were separated in 3 groups (n=8) according to the submitted treatments: Group 1: AAA; Group 2: mechanical brushing with dentifrice RDA* 68 (Colgate); and Group 3: mechanical brushing with dentifrice RDA* 180 (Colgate Total Plus Whitening). New readings on color and surface roughness were taken after 480 hours of AAA and in intervals of 41 minutes of brushing (=14.600 cycles) until 205 minutes. The samples initially submitted to AAA (n=4) received mechanical brushing with dentifrice RDA* 68 and 180, according to previously described methodology and new readings on color and roughness were taken. Data (before and after tests) were statistically analyzed (2- way ANOVA repeated measures, Bonferroni, p<0,05) and it was observed a higher composite color alteration compared with mechanical brushing when submitted to AAA with a statistically significant difference (p<0,05) between them. There was no statistically significant difference (p>0,05) on color stability of materials when the dentifrices abrasiveness were compared, but it was significant for surface roughness degradation (p<0,05), higher when materials were brushed with RDA* 180. Regarding time brushing, there was no statistically significant difference (p>0,05) for color alteration and roughness surface of materials and the same occurred for samples brushed after AAA. It was concluded that AAA interferes on color stability and the simulated brushing on surface roughness degradation of composites regardless the time of used dentifrice, but it was higher for more abrasive dentifrices. Moreover, abrasiveness and time of used dentifrice do not alter the capacity of staining removal and the surface roughness of composites.

<p>A 6082 aluminium alloy has been characterized with regard to the influence of surface roughness on fatigue strength.</p><p>Fatigue life testing of smooth specimens was used to establish reference curves for the material in extruded and forged T6 condition. The extruded material was found to have better fatigue strength than the forged material, although the cyclic stress-strain response was similar for both. The forged material was tested in T5, T6 and T7 tempers, showing no significant difference in fatigue strength.</p><p>Surface roughness was created by circumferential grinding of cylindrical test specimens, and the surface topography was measured using a white light interferometry microscope. The measurements proved to be accurate, although errors were observed for certain surface features. Residual stresses were quantified by X-ray diffraction. Compressive residual stresses of around 150 MPa were found in both rough and smooth specimens. Load cycling did not significantly alter the surface residual stresses.</p><p>Stress solutions ahead of all major surface grooves were found using a linear elastic material model. Estimates of cyclic stresses and strains were calculated in the notch roots using different Neuber corrections of the linear solution. The results were compared to finite element analysis employing a bilinear kinematic hardening model. A generalized version of the Neuber correction was found to be within 20% of the nonlinear finite element results.</p><p>Several empirical models for the notch sensitivity factor were investigated. These were found to be unable to describe the notch influence on fatigue life and initiation life. In order to follow this approach, it was recommended that different test specimens should be used where the short fatigue crack growth could be monitored.</p><p>It was shown that microstructural fracture mechanics theories could be used to estimate the fatigue limit of rough surfaces. In some cases, initiation from material defects or weaknesses would override the influence of surface geometry. In one specimen, the initiation appeared to have started as at a de-bonded grain, while in other cases, initiation was thought to have started at larger second phase particles embedded in notch roots. Further work in this area should focus on statistical descriptions of surface roughness, inherent material defects, and their interaction.</p>

With the growing trend in use of 3D laser scanning technology for data collection, it is important to study the various potential applications of this revolutionary technology. One such application is the measurement of road roughness at both large and small scales. At larger extents, terrestrial laser scanning (TLS) is compared to several current techniques to measure road profiles including digital levels, inclinometers, and inertial profilers. An overall indicator of roughness (e.g. International Roughness Index, IRI) can be obtained from these road profiles and is used by state DOTs to determine the pavement quality. Since TLS is able to collect a large, dense set of data relatively quickly, this technology could provide states with an additional tool to both measure pavement roughness and collect data for the entire roadway. TLS has the added benefit of being able to generate multiple profiles across the roadway efficiently. At a fine scale, micron resolution 3D laser scanners can be utilized to determine the influence of asphalt mix designs on the roughness of the pavement. Of particular interest is the selection of predominant aggregate size within the mix. Results showed that TLS can determine pavement profiles and comparable IRI results to those from current methods. The elevation values collected within the profile were accurate within expected ranges. However, cross correlations, which take into account the location of the roughness, were poor, indicating that TLS is not an effective method to determine a reference profile. TLS was used to determine the cross slopes across the roadway, something that cannot be done with data from an inclinometer or inertial profiler. / Graduation date: 2012 / Zipped file contains 4 file types. Excel files (.xlsx and .xls) can be opened using Microsoft Excel. OBJ files (.obj) are geometry definition file formats intended to be imported into a software program to manipulate 3D laser scans and can also be opened using Notepad++ or another powerful text editor. Notepad++ is freely available for download on the Web. PVP files (.pvp) are project files that contain project settings and profile data and can be opened with ProVAL, a freely available engineering software application used to view and analyze roadway profiles. ERD files (.ERD) are standard file formats used for storing numbers in tabular form and can be opened with Notepad++ or another powerful text editor. These files contain roadway profiles and are designed to be imported into ProVAL.

A 6082 aluminium alloy has been characterized with regard to the influence of surface roughness on fatigue strength. Fatigue life testing of smooth specimens was used to establish reference curves for the material in extruded and forged T6 condition. The extruded material was found to have better fatigue strength than the forged material, although the cyclic stress-strain response was similar for both. The forged material was tested in T5, T6 and T7 tempers, showing no significant difference in fatigue strength. Surface roughness was created by circumferential grinding of cylindrical test specimens, and the surface topography was measured using a white light interferometry microscope. The measurements proved to be accurate, although errors were observed for certain surface features. Residual stresses were quantified by X-ray diffraction. Compressive residual stresses of around 150 MPa were found in both rough and smooth specimens. Load cycling did not significantly alter the surface residual stresses. Stress solutions ahead of all major surface grooves were found using a linear elastic material model. Estimates of cyclic stresses and strains were calculated in the notch roots using different Neuber corrections of the linear solution. The results were compared to finite element analysis employing a bilinear kinematic hardening model. A generalized version of the Neuber correction was found to be within 20% of the nonlinear finite element results. Several empirical models for the notch sensitivity factor were investigated. These were found to be unable to describe the notch influence on fatigue life and initiation life. In order to follow this approach, it was recommended that different test specimens should be used where the short fatigue crack growth could be monitored. It was shown that microstructural fracture mechanics theories could be used to estimate the fatigue limit of rough surfaces. In some cases, initiation from material defects or weaknesses would override the influence of surface geometry. In one specimen, the initiation appeared to have started as at a de-bonded grain, while in other cases, initiation was thought to have started at larger second phase particles embedded in notch roots. Further work in this area should focus on statistical descriptions of surface roughness, inherent material defects, and their interaction.

In this thesis a study of the factors affecting virus and virus-sized particle transport in discrete fractured dolomite rocks is presented. Physical and chemical characteristics of two fractured rocks were determined, including fracture aperture distribution, rock matrix porosity, mineral composition, and surface charge. Hydraulic and transport tests were conducted in the fractures with a conservative solute (bromide) and carboxylate-modified latex (CML) microspheres of three sizes (20, 200, and 500 nm in diameter). The earlier arrival of larger microspheres as compared to bromide indicated the effects of pore-size exclusion and preferential flow paths in the fractures. The tailing of the bromide and the smaller microsphere (20 nm) in the breakthrough curves (BTC) indicated the diffusive mass transfer between the mobile water (flowing) and immobile water (stagnant water in the low aperture areas and porous rock matrix). The effects of ionic strength and cation type on the transport of viruses (bacteriophages MS2 and PR772) and virus-sized microspheres (20 and 200 nm) were determined from the transport tests in a fracture at three levels of ionic strength (3, 5, and 12 mM) and composition (containing Na+ and/or Ca2+ ions). Retention of the microspheres and bacteriophages increased with increasing ionic strength. The addition of divalent ions (Ca2+) influenced the retention to a greater extent than monovalent ions (Na+). The effects of the aperture distribution variability, matrix diffusion, and specific discharge on the solute and microsphere transport were determined from the transport tests conducted in two fractures. The higher variability in the aperture distribution contributed to higher solute dispersion, and flow channeling as evident from the breakthrough curves for individual spatially distributed outlets. A three-dimensional model simulation of the bromide transport with varying matrix porosity identified that the porous matrix influenced the solute transport. In the transport tests, retention of the microspheres decreased with increasing specific discharge in both fractures. The results of this research have helped in identifying the important factors and their effects on solute, virus, and virus-sized colloid transport in fractured dolomite rocks, which can be useful in determining the risk of pathogen contamination of water supplies in fractured dolomite rock aquifers.

The frictional behavior of soil-construction material interfaces is of significant importance in geotechnical engineering applications such as retaining structures, pile foundations, geosynthetic liners, and trenchless technologies. Since most failures initiate and develop on the interfaces, special attention is required to predict the capacity of these weak planes in the particular application. Pipe-jacking and microtunneling technologies are being more widely used over the past decade and there is significant interest to predict the jacking forces and jacking distances achievable in order to achieve more efficient design and construction. This study focuses on the evaluation of the frictional characteristics and factors affecting the shear strength of pipe-soil interfaces. Eight different pipes made from fiber reinforced polymer (FRP), polycrete, steel, concrete, and vitrified clay were tested in the experimental program. For this purpose, a new apparatus was designed to conduct conventional interface direct shear testing on pipes of different curvature. This device allows coupons cut from actual conduits and pipes to be tested in the laboratory under controlled conditions. The apparatus includes a double-wall shear box, the inner wall of which is interchangeable to allow for testing against surfaces of different curvatures. By considering a narrow width section, the circular interface of pipes was approximated with a surface along the axial direction and the boundary is defined by the inner box. Roughness tests were performed using a stylus profilometer to quantify the surface characteristics of the individual pipes and relate these to the interface shear behavior. The surface topography showed different degrees of variability for the different pipes. To extend the range of roughness values tested and force the failure to occur in the particulate media adjacent to the interface, two artificial pipe surfaces were created using rough sandpapers. Interface shear tests were performed using the new apparatus with air-pluviated dense specimens of Ottawa 20/30 sand. Additional tests were performed using Atlanta blasting sand to evaluate the effect of particle angularity. The effect of normal stress and relative density were also examined. The interface strength was shown to increase with surface roughness and finally reach a constant value above a certain critical roughness value, which corresponded to the internal strength of the soil itself. This represented the failure location moving from the interface into the soil adjacent to the interface. Both the strength and the shearing mechanism were thus affected by the surface topography. It was also shown that the interface shear strength was affected by particle angularity, relative density and normal stress.