• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 746
  • 596
  • 257
  • 118
  • 53
  • 17
  • 16
  • 16
  • 16
  • 16
  • 16
  • 16
  • 14
  • 14
  • 10
  • Tagged with
  • 2155
  • 565
  • 466
  • 247
  • 214
  • 213
  • 201
  • 200
  • 174
  • 166
  • 137
  • 133
  • 121
  • 120
  • 104
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
261

Carbon nanotubes on carbon fibers : synthesis, structures and properties

Zhang, Qiuhong, January 2010 (has links)
Thesis (Ph.D. in Materials Engineering) -- University of Dayton. / Title from PDF t.p. (viewed 06/23/10). Advisor: Liming Dai. Includes bibliographical references (p. 136-162). Available online via the OhioLINK ETD Center.
262

Dielectric barrier discharge-initiated fiber modification

Vander Wielen, Lorraine C. January 2005 (has links)
Thesis (Ph. D.)--Institute of Paper Science and Technology, Georgia Institute of Technology, 2005. / Institute of Paper Science and Technology, Committee Chair. Bibliography:
263

Impact of dietary fiber level and physical from on performance of lactating dairy cows

Woodford, James Alan. January 1984 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1984. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 84-92).
264

Effect of detergent type on wear-life of an apparel item varying by fiber content

Jansen, Kathy. January 1975 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1975. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Bibliography: leaves 164-172.
265

Scintillator wavelength influence in an optical dosimeter : Master of Medical Physics, Department of Physics and Astronomy, University of Canterbury, Christchurch, New Zealand /

Chen, Tom Chien-Sheng. January 2006 (has links)
Thesis (M. Sc.)--University of Canterbury, 2006. / Typescript (photocopy). Includes bibliographical references (leaves 60-62). Also available via the World Wide Web.
266

Surface characterization and adhesive bonding of carbon fiber-reinforced composites /

Chin, Joannie W., January 1994 (has links)
Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1994. / Abstract. Includes bibliographical references. Also available via the Internet.
267

Adaptações morfofuncionais e respostas moleculares do músculo esquelético de ratos submetidos ao treinamento resistido /

Aguiar, Andreo Fernando. January 2011 (has links)
Orientador: Maeli Dal Pai Silva / Banca: Claudio Alexandre Gobatto / Banca: Selma Maria Michelin Mateus / Banca: André Soares Leopoldo / Banca: Robson Francisco Carvalho / Resumo: Embora fortes evidências demonstrem que os fatores de regulação miogênica (MRFs) e o fator de crescimento semelhante à insulina (IGF-I) apresentem um importante papel na resposta hipertrófica após treinamento resistido (TR) agudo, permanece desconhecido se a resposta dos MRFs e IGF-I também ocorre durante a adaptação ao TR a longo-prazo. Portanto, o objetivo deste estudo foi testar a hipótese de que a resposta hipertrófica e modulação das fibras do músculo esquelético após TR a longo-prazo poderia estar associada ao aumento na expressão gênica dos MRFs e IGF-I. Ratos Wistar (80 dias de idade, 250-300 g) foram divididos em quatro grupos: Controle 8 semana (C8, n = 8), Treinado 8 semanas (T8, n = 8), Controle 12 semanas (C12, n = 8) e Treinado 12 semanas (T12, n = 8). Os grupos T8 e T12 foram submetidos a um programa de TR progressivo (3 dias/semana) durante 8 e 12 semanas, respectivamente. O protocolo de treinamento consistiu de quatro séries de 10-12 repetições, com um período de descanso de 40 segundos entre cada série, realizado a 65-75% de uma repetição máxima (1RM). Ao término do experimento, os animais foram sacrificados e o músculo plantar coletado para as análises morfológica e molecular. O TR durante 8 e 12 semanas não promoveu qualquer alteração (p > 0,05) significante no ganho de peso corporal e consumo alimentar dos grupos T8 e T12 em relação aos grupos C8 e C12, respectivamente. Após 8 e 12 semanas de TR, a força absoluta (T8: 69,7% and T12: 126,0%, p < 0,05) e relativa (T8: 36,1% and T12: 57,7%, p < 0,05) foi significantemente elevada nos grupos T8 e T12, em comparação aos seus respectivos controles. No entanto, houve um similar aumento da área de secção transversal (AST) das fibras musculares (T8: 29% vs. T12: 35%, p > 0,05) entre os grupos T8 e T12, comparados aos grupos C8 e C12, respectivamente... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Although strong evidence show that the myogenic regulatory factors (MRFs) and insulin-like growth factor (IGF-I) have important roles in the hypertrophy response after acute resistance training, it is still unclear if response of MRFs and IGF-I also occurs during the adaptation to prolonged periods of resistance training (RT). Therefore, the purpose of this study was to test the hypothesis that fiber-types transition and hypertrophy during long-term RT could be associated with increased MRFs and IGF-I mRNA expression in the skeletal muscle. Male Wistar rats (80 days old, 250-300 g) were divided into four groups: 8 weeks control (C8, n = 8), 8-weeks trained (T8, n = 8), 12-weeks control (C12, n = 8), 12-weeks trained (T12, n = 8). T8 and T12 groups were submitted to a progressive RT program (3 day/week) for 8 and 12 weeks, respectively. The training protocol consisted of four sets of 10-12 repetitions, with a 40 s rest period between each set, performed at 65-75% of one repetition maximum (1RM). At the end of the experiment, animals were sacrificed and the plantaris muscle collected for morphological and molecular analysis. The RT did not change (p > 0.05) in body weight gain and food intake in the T8 and T12 compared to the C8 and C12 groups, respectively. After 8 and 12 weeks of RT, the absolute (T8: 69.7% vs. T12: 126.0%; p < 0.05) and relative (T8: 36.1% vs. T12: 57.7%; p < 0.05) strength (relative 1RM) was significantly elevated in the T8 e T12 groups, compared to respective control groups. RT for 8 and 12 weeks induced similar increase in myogenin (T8: 44.8% vs. T12: 37.7%; p > 0.05), MyoD (T8: 22.9% vs. T12: 22.3%; p > 0.05) and muscle fiber crosssectional area (CSA) (T8: 29% vs. T12: 35%; p > 0.05) in the T8 and T12, compared to C8 and C12 groups, respectively. After 8 weeks of RT, IGF-I increased in 30.1% in the T8 compared to C8 group, but returned to baseline after 12 weeks... (Complete abstract click electronic access below) / Doutor
268

Obtenção e caracterização de fibras poliméricas e cerâmicas pela técnica de “blow-spinning”

Silva, Cícero Rafael Cena da [UNESP] 27 May 2013 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:32:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-05-27Bitstream added on 2014-06-13T20:03:16Z : No. of bitstreams: 1 silva_crc_dr_ilha.pdf: 6087060 bytes, checksum: 2127fd1ec2b4d4c0c5fd36f87f90745b (MD5) / Fibras poliméricas, compósitos e estruturas cerâmicas do tipo fibrosas foram produzidas com sucesso utilizando a recente técnica de Blow-spinning. As fibras poliméricas foram obtidas a partir de soluções de poli(vinil pirrolidona) - PVP dissolvido em álcool isopropílico. Um estudo sistemático sobre a influência dos parâmetros de solução (concentração, viscosidade e solvente) e os parâmetros experimentais (taxa de injeção, pressão do ar, velocidade de rotação do coletor e tamanho da agulha) sobre a formação e morfologia das fibras foi conduzido a fim de determinar as melhores condições de síntese. Os estudos realizados indicaram que não ocorrem mudanças nas propriedades térmicas ou estruturais do polímero causada devido ao processo de fiação. As fibras compósitos polímero/precursor cerâmico foram submetidas a diferentes condições de tratamento térmico, envolvendo taxa de aquecimento, tempo de tratamento e temperatura, no intuito de determinar as melhores condições de cristalização da fase cerâmica desejada, no caso o material cerâmico supercondutor Bi2Sr2Cu1Ca2Ox (BSCCO-2212), procurando presevar ao final uma estrutura do tipo fibrosa. Estudos de difração de raios-x (DRX) e microscopia eletrônica de varredura (MEV) foram realizados nas amostras cerâmicas para determinar suas características estruturais, microestruturais e composição finais. Os resultados indicaram que a fase desejada BSCCO (2212) foi obtida com sucesso coexistindo com uma fase secundária atribuída como Bi1,916Sr1,84CuO5,482. A morfologia da amostra foi constituída de aglomerados grandes e contínuos, entremeados por uma estrutura do tipo fibrosa / Polymer fibers, composite and ceramic-type fibrous structures were successfully produced using the Blow-spinning technique. The fibers were obtained from poly (vinylpyrrolidone) - PVP solutions by using isopropyl alcohol as solvent. A systematic study on the influence of solution parameters (concentration, viscosity and solvent) and experimental parameters (injection rate, air pressure, rotational speed of the collector and size of the needle) on the formation and morphology of the fibers was performed to determine the best conditions for synthesis. The results shown no changes in the thermal and structural properties of the polymer caused due to the spinning process. The fiber composite polymer / ceramic precursor were thermal treated at different routes, involving heating rate, treatment time and temperature in order to determine the best conditions of Bi2Sr2Cu1Ca2Ox (BSCCO-2212) superconductor phase crystallization preserving at the end the fibrous structure. Studies of x-ray diffraction (XRD) and scanning electron microscopy (SEM) were performed on ceramic samples to determine their structural characteristics, composition and final microstructure. The results shown that desired BSCCO (2212) phase was successfully obtained coexisting with a secondary phase Bi1,916Sr1,84CuO5,482. The sample morphology was constituted of continuous agglomerate intermingled with a fiber structure
269

Obtenção e caracterização de fibras poliméricas e cerâmicas pela técnica de "blow-spinning" /

Silva, Cícero Rafael Cena da. January 2013 (has links)
Orientador: José Antonio Malmonge / Banca: Walter Katsumi Sakamoto / Banca: Fernando Rogério de Paula / Banca: Marcelo Ornaghi Orlandi / Banca: Alessandra de Almeida Lucas / Resumo: Fibras poliméricas, compósitos e estruturas cerâmicas do tipo fibrosas foram produzidas com sucesso utilizando a recente técnica de Blow-spinning. As fibras poliméricas foram obtidas a partir de soluções de poli(vinil pirrolidona) - PVP dissolvido em álcool isopropílico. Um estudo sistemático sobre a influência dos parâmetros de solução (concentração, viscosidade e solvente) e os parâmetros experimentais (taxa de injeção, pressão do ar, velocidade de rotação do coletor e tamanho da agulha) sobre a formação e morfologia das fibras foi conduzido a fim de determinar as melhores condições de síntese. Os estudos realizados indicaram que não ocorrem mudanças nas propriedades térmicas ou estruturais do polímero causada devido ao processo de fiação. As fibras compósitos polímero/precursor cerâmico foram submetidas a diferentes condições de tratamento térmico, envolvendo taxa de aquecimento, tempo de tratamento e temperatura, no intuito de determinar as melhores condições de cristalização da fase cerâmica desejada, no caso o material cerâmico supercondutor Bi2Sr2Cu1Ca2Ox (BSCCO-2212), procurando presevar ao final uma estrutura do tipo fibrosa. Estudos de difração de raios-x (DRX) e microscopia eletrônica de varredura (MEV) foram realizados nas amostras cerâmicas para determinar suas características estruturais, microestruturais e composição finais. Os resultados indicaram que a fase desejada BSCCO (2212) foi obtida com sucesso coexistindo com uma fase secundária atribuída como Bi1,916Sr1,84CuO5,482. A morfologia da amostra foi constituída de aglomerados grandes e contínuos, entremeados por uma estrutura do tipo fibrosa / Abstract: Polymer fibers, composite and ceramic-type fibrous structures were successfully produced using the Blow-spinning technique. The fibers were obtained from poly (vinylpyrrolidone) - PVP solutions by using isopropyl alcohol as solvent. A systematic study on the influence of solution parameters (concentration, viscosity and solvent) and experimental parameters (injection rate, air pressure, rotational speed of the collector and size of the needle) on the formation and morphology of the fibers was performed to determine the best conditions for synthesis. The results shown no changes in the thermal and structural properties of the polymer caused due to the spinning process. The fiber composite polymer / ceramic precursor were thermal treated at different routes, involving heating rate, treatment time and temperature in order to determine the best conditions of Bi2Sr2Cu1Ca2Ox (BSCCO-2212) superconductor phase crystallization preserving at the end the fibrous structure. Studies of x-ray diffraction (XRD) and scanning electron microscopy (SEM) were performed on ceramic samples to determine their structural characteristics, composition and final microstructure. The results shown that desired BSCCO (2212) phase was successfully obtained coexisting with a secondary phase Bi1,916Sr1,84CuO5,482. The sample morphology was constituted of continuous agglomerate intermingled with a fiber structure / Doutor
270

Paper tensile properties as determined by fibre origin in the coniferous wood matrix

Sun, Bernard Ching-Huey January 1970 (has links)
This study examines the hypothesis that coniferous wood fibre origin is maintained even when purified pulps are subjected to severe mechanical (beating) and chemical (decrystallizing) treatments. Four to five intra-incremental sulphate pulps obtained from each of three species, eastern larch (Larix lariaina (Duroi) K. Koch), Douglas fir (Pseudotsuga menziessii (Mirb.) Franco) and balsam fir (Abies balsamea (L.) Mill), were purified and machined to one or three levels EL (170 ± 45 ml Csf), DF (615 + 90 ml Csf; 328 + 43 ml Csf; 168 ± 62 ml Csf) and BF (190 + 30 ml Csf). Thereafter, cellulose supermolecular structures were altered by monoethylamine swelling, with changes (48 ± 2% vs. 68 ± 2%) quantified as fibre crystallinity index measured by X-ray diffractometry. Paper sheet apparent densities and tensile parameters (maximum strength, "stretch," modulus of elasticity and rupture energy) were determined. Fibre surface areas and sheet bonded states were estimated by light scattering coefficient measurements. The effects of wood origin on paper sheet physical-mechanical properties reported by other researchers were reaffirmed in this study, with all factors decreasing progressively across growth increments. The differences of wood intra-incremental, as well as species origins, were not removed by conventional pulping and papermaking processes, or additional treatments such as severe beating or major alteration of the basic cellulose structures as practiced in the study. Paper sheet tensile properties were related directly to sheet apparent density. Correlation coefficients as high as 0.979 and 0.989 were obtained for 00% and 82% monoethylamine decrystallized fibre sheets, respectively. Sheet density was inversely related to wood specific gravity and was found to be independent of wood species, degree of beating and decrystallization treatments. It is shown that fibre bonding potential is not the only factor influencing paper sheet strength. Intrafibre characteristics, such as cellulose supermolecular structures, have a highly significant effect on paper sheet strength as well. In addition, specific energy of "bond failure" (irreversible energy consumed per unit sheet surface formed as result of tensile straining) was higher for earlywood than for latewood sheets. This energy quantity depends on beating degree and differs according to species, as well as intra-incremental origin. The paper sheet light scattering coefficient (L.S.C.)-density relationship also depended on wood fibre origin. Earlywood sheet L.S.C. decreased with increased beating and sheet density, but latewood sheet L.S.C. remained almost unaffected. This observation explains why whole-wood fibre sheet L.S.C.-density relationships vary with pulp types as recorded in the literature. / Forestry, Faculty of / Graduate

Page generated in 0.0461 seconds