Torsion of cylindrical shafts has long been a basic subject in the classical theory of elasticity. In 1998 Swanson proposed a theoretical solution for the torsion problem of laminated composites. He adopted the traditional formulation of the torsion problem based on Saint Venant's torsion theory. The eigenfunction expansion method was employed to solve the formulated problem. The analytical method is proposed in this study enabling one to solve the torsion problem of laminated composite beams. Instead of following the classical Saint Venant theory formulation, the notion of effective elastic constant is utilized. This approach uses the concept of elastic constants, and in this context the three-dimensional non-homogeneous orthotropic laminate is replaced by an equivalent homogeneous orthotropic material. By adopting the assumptions of constant stress and constant strain, the effective shear moduli of the composite laminates are then derived. Upon obtaining the shear moduli of the equivalent homogeneous material, the effective torsional rigidity of the laminated composite rods can be determined by employing the theory developed by Lekhnitskii in 1963. Finally, the predicted results based on the present analytical approach are compared with those by the finite element, the finite difference method and Swanson's results. / Master of Science

This research provides the original work on the geometry factors selection for single crystal sapphire optical fiber (SCSF) to improve the optical property in sensing applications. Single crystal sapphire fibers were fabricated with a Laser Heated Pedestal Growth (LHPG) system, which was constructed in-house at Virginia Tech. The cost effective, high efficiency and fully operational Laser-heated Pedestal Growth (LHPG) system as well as the fiber fabrication process were also demonstrated in this research. The results indicated the windmill single crystal sapphire optical fiber (SCSF) will readily improve the performance of current fiber optic sensors in the harsh environment and potentially enable those that are limited by the optical property of unclad single crystal sapphire optical fiber (SCSF). / Ph. D. / This research provides the original work on the geometry factors selection for single crystal sapphire optical fiber (SCSF) to improve the optical property in sensing applications. Single crystal sapphire fibers were fabricated with a Laser Heated Pedestal Growth (LHPG) system, which was constructed in-house at Virginia Tech. The cost effective, high efficiency and fully operational Laser-heated Pedestal Growth (LHPG) system as well as the fiber fabrication process were also demonstrated in this research. The results indicated the windmill single crystal sapphire optical fiber (SCSF) will readily improve the performance of current fiber optic sensors in the harsh environment and potentially enable those that are limited by the optical property of unclad single crystal sapphire optical fiber (SCSF).

Volume phase holographic (VPH) gratings have been designed for use in many areas of science and technology such as optical communication, medical imaging, spectroscopy and astronomy. The goal of this dissertation is to design a volume phase holographic grating that provides diffraction efficiencies of at least 70% for the entire visible wavelengths and higher than 90% for red, green, and blue light when the incident light is unpolarized. First, the complete design, simulation and optimization of the volume hologram are presented. The optimization is done using a Monte Carlo analysis to solve for the index modulation needed to provide higher diffraction efficiencies. The solutions are determined by solving the diffraction efficiency equations determined by Kogelnik's two wave coupled-wave theory. The hologram is further optimized using the rigorous coupled-wave analysis to correct for effects of absorption omitted by Kogelnik's method. Second, the fabrication or recording process of the volume hologram is described in detail. The active region of the volume hologram is created by interference of two coherent beams within the thin film. Third, the experimental set up and measurement of some properties including the diffraction efficiencies of the volume hologram, and the thickness of the active region are conducted. Fourth, the polarimetric response of the volume hologram is investigated. The polarization study is developed to provide insight into the effect of the refractive index modulation onto the polarization state and diffraction efficiency of incident light.

Thermometry measurements were carried out using planar laser induced phosphorescence in conjunction with thermographic phosphors in heated turbulent jets and laminar flames in order to further develop the technique for usage in flames. Two dimensional thermometry measurements are essential to improve the understanding of combustion processes, as temperature governs soot pyrolysis, leading to soot formation. Two particular thermographic phosphors, BAM and YAG:Dy were tested and compared and it was found that they were unsuitable for gas phase flame thermometry measurements. Soot volume fraction measurements were carried out using planar two colour laser induced incandescence in gaseous and liquid fuel flames. The gas fuel flames were diluted with nitrogen, carbon dioxide and hydrogen individually and then with nitrogen and hydrogen together, as well as carbon dioxide and hydrogen together, separately. Results revealed the dilution effects of the gases on the soot formation process, where increasing nitrogen percentage in the flow decreased SVF, carbon dioxide reduced it further and hydrogen showed no marked difference. Biodiesels were compared with each other and with diesel in a wick burner in order to analyse their compositional effects on soot. Biodiesel composition was measured using gas chromatography. The sooting tendencies of the biodiesels were as expected, fuels with a longer average carbon chain length and a higher degree of unsaturation were found to produce more soot than shorter, more saturated fuels. Diesel was sootier than all of the biofuels tested, due to containing aromatics and a lower oxygen content. A pilot study was also done, where the performance and emissions of biofuels and biofuel-diesel blends were tested in a gas turbine engine, in order to relate the investigation to real world situations.

Le dépliement thermique et chimique est raisonnablement compris, mais pas les effets déstabilisants de la pression. Dans une tentative de caractérisation des facteurs à la base des effets de la pression sur les protéines, nous avons étudié le dépliement sous pression d'une protéine modulaire, le domaine ankyrine du récepteur Notch (Nank1-7*), ainsi que plusieurs mutants en nombre de motifs. Nos expériences montrent un dépliement à deux états sous pression. La dépendance à la température des sauts de pression a montré qu'à faibles températures l'ensemble d'état de transition(TSE) est proche en volume de l'état replié alors que son énergie est proche de celle de l'état déplié,ce qui est significatif d'une déshydratation importante de la barrière énergétique, et a montré que l'augmentation de la température conduit à un TSE plus grand en volume que l'état replié. Ce comportement révèle une grande plasticité du TSE de Nank1-7*. L'étude des mutants (délétion demotifs) nous a montré que le ΔV n'est déterminé ni par l'hydratation des liaisons peptidiques ni par l'hydratation différentielle des acides aminés, mais par l'existence de vides internes exclus du solvant. Seule une petite fraction des cavités est déterminante pour le ΔV, celles qui ne sont pas significativement solvatées dans les coeurs hydrophobes. Finalement, nous avons déterminé que le TSE possède même des cavités plus grandes, et nous émettons l'hypothèse que l'énergétique et la dynamique contribuent aux effets de la pression sur les protéines. / Thermal and chemical unfolding of proteins are reasonably well understood, but the destabilizingeffects of pressure are not. In an attempt to characterize the factors at the basis of pressure effects,we investigated the pressure unfolding of a modular protein, the ankyrin domain of the Notch receptor(Nank17*) and several of its deletion constructs. All our experiments were consistent with a simpletwo-state folding/unfolding transition under pressure. The temperature dependence of pressure-jumpsdemonstrated that at low temperature, the transition state ensemble (TSE) lies close in volume to thefolded state despite its unfolded-like energetics, consistent with significant dehydration at the barrier,and that increasing temperature leads to a volume of the TSE larger than that of the folded state. Thisbehavior reveals a high degree of plasticity of the TSE of Nank17*. Studies of the deletion mutantsshowed us that ΔV is determined not by hydration of peptide bonds or by differential hydration ofresidues, but by the existence of internal solvent-excluded void volumes. Only a small fraction of theinternal cavities are relevant of the ΔV, those that are not significantly solvated in the hydrophobiccore. Finally, we determined that the transition state ensemble show even larger cavities, and wehypothesize both energetics and dynamics contribute to pressure effects on proteins.

Ao longo das décadas de 1990 e 2000, Brasil e Argentina passaram por mudanças estruturais em suas economias para poderem contornar as dificuldades impostas pelos novos cenários econômicos internacional e doméstico. Nesse contexto, já não havia a possibilidade de controlar os fluxos de capitais como em décadas anteriores para equilibrar déficits comerciais. A integração econômica passou a ser vista como uma forma de expandir o comércio dos parceiros, o nível de emprego e de crescimento econômico. Os ganhos após as negociações do bloco foram consideráveis, marcados por interrupções decorrentes de crises externas e internas a Brasil e Argentina. Durante as crises os setores ineficientes manifestaram-se para protegerem seus mercados e adiar a queda das barreiras comerciais e tornaram mais nítidas as limitações da estrutura regulatória do comércio. Entre 1994 e 2005, alguns setores inicialmente inexpressivos ganharam participação maior em relação ao total comercializado, demonstrando a importância da criação de novos mercados para o crescimento de segmentos anteriormente sem demanda, como foi o caso do setor de equipamentos eletrônicos para o Brasil. Pela observação dos setores envolvidos na relação comercial, pode-se observar a capacidade de geração de emprego, captação de divisas, expansão da demanda por produtos intensivos em tecnologia. Tanto para o Brasil quanto para a Argentina o setor de veículos automotores, reconhecidamente de alto valor agregado e intensivo em tecnologia, apresentou crescimento de vendas notável, utilizando-se das novas possibilidades oferecidas pela integração. / Throughout the decades of 1990 and 2000, Brazil and Argentina went through structural changes in their economies in order to face the restrictions imposed by the new domestic and international economic environment. It was not possible anymore to control capital flows as it was in previous decades to balance trade deficits. The economic integration became a way to increase trade between partners, the employment level and the economic growth. After negotiations, the gains were considerable and marked by interruptions as a result of domestic and international crises faced by Brazil and Argentina. At the same time, the inefficient sectors used the harsh moments to impose trade barriers, protect their market shares and postpone the liberalization process, making it clear the limitations of the regulatory structure. From 1994 to 2005 some sectors initially not much expressive expanded their participation on the total of trade, showing the importance of the creation of new markets for the development of sectors, as it was for the brazilian sector of electronics equipments. Analysing the sectors involved in the trade makes it possible to see their capacity to generate employment, obtain foreign exchange and increase the demand for high technology goods. As for Brazil and Argentina, the automobile sector, known as for being of high added value and intensive in technology, has demonstrated remarkable growth in sales, taking advantage of the new possibilites granted by the integration.

Polímeros com grupos azobenzênicos exibindo fotoisomerização reversível trans-cis-trans tem sido usado para armazenamento óptico, chaves ópticas e produção de grades de relevo. A fotoisomerização produzida por luz linearmente polarizada cria uma orientação molecular perpendicular a polarização da luz (hole-burning angular) que induz a birrefringência na amostra. Neste trabalho, medimos a birrefringência foto induzida em filmes de poliestireno dopado com corante vermelho disperso 1 (DR1) em função da temperatura. A amplitude da birrefringência aumenta com a temperatura entre 20 e 180 K, atinge um máximo e diminui a zero próximo da temperatura de transição vítrea do polímero, a qual é da ordem de 373 K. A amplitude da birrefringência é proporcional a concentração de DR1 e também depende da história térmica da amostra. Propõe-se um modelo teórico que leva em conta a mudança de volume livre do polímero com a temperatura, representando um passo além dos modelos conhecidos. Assumimos que as moléculas de DR1 ocupam cavidades do polímero e a função distribuição Gama é usada para descrever a distribuição dos volumes das cavidades, enquanto a função Gaussiana descreve as flutuações térmicas de volume em torno de seu valor médio. A isomerização das moléculas de DR1 só podem ocorrer em cavidades com volume maior que um valor crítico. A comparação entre o modelo e os dados experimentais mostra uma razoável concordância. O modelo prevê corretamente a dependência da birrefringência com o tempo, com a temperatura e com a história térmica da amostra, já que o volume livre do polímero depende dessa história. / Polymers with azobenzene groups exhibiting reversible trans-cis-trans photoisomerization characteristics have been used for optical storage, optical switching and production of surface relief gratings. The photoisomerization produced by a linearly polarized light leads to a molecular orientation perpendicular to the light polarization (angular hole burning), which induces a birefringence on the sample. In this work we report on the photoisomerization of films of polystyrene (PS) doped with disperse red 1 (DR1), performed at various temperatures. The birefringence amplitude rises with temperature from 10 to 270 K, goes through a maximum and decays to zero near the polystyrene transition temperature, which is 370 K. The birefringence amplitude, at a given temperature, is proportional to the DR1 content and also depends on the sample thermal history. We proposed a model that accounts for the change in free volume of the polymer with temperature though representing an improvement to well-known models. We assume that the azobenzene group is inside a local free volume and the Gamma distribution function is used to describe a local free volume distribution in the sample while the Gaussian distribution function gives the thermal free-volume fluctuation. Isomerization of the azobenzene group only occurs if the local free volume is larger than a critical value. Comparison with the experimental data shows that the model explains the temporal evolution, the temperature dependence of the birefringence and how the birefringence is affected by the sample thermal history, as the sample free volume of the polymer depends on such history.

O assoreamento de reservatórios formados pela construção de barragens interfere inevitavelmente no seu volume útil. O volume útil é o compartimento responsável pelo armazenamento da água para o atendimento dos usos consuntivos e não consuntivos do sistema e a sua redução altera o atendimento das demandas. Nesta pesquisa foi investigada a interferência do processo de assoreamento do reservatório de Promissão, localizado no Médio Tietê, na geração de energia elétrica da Usina Hidrelétrica Mário Lopes Leão. A quantificação do assoreamento do reservatório nos últimos 30 anos de operação foi realizado pela comparação da topografia original do lago na época de seu enchimento, em 1975, com a topo-batimetria levantada no ano de 2005. O modelo RESSASS foi utilizado para a análise da variação do volume do reservatório de 1975 a 2005, bem como para a previsão do assoreamento do reservatório até os anos de 2055 e 2105. A redução do volume útil do reservatório foi de 4,14% de 1975 a 2005, chegando a 9,46% em 2105. O assoreamento do reservatório também foi estudado através da análise qualitativa dos dados, identificando os afluentes que apresentavam maior grau de assoreamento. A análise da interferência da variação do volume útil do reservatório na geração de energia elétrica da usina foi realizada com o modelo AcquaNet. O reservatório de Promissão foi estudado isoladamente. As simulações foram realizadas considerando as diferentes curvas cota vs. área vs. volume de 1975, 2005, 2055 e 2105, além da consideração de dois níveis mínimos de operação: 379,7 m, nível mínimo do reservatório, e 381,0 m, nível mínimo em que o reservatório é operado em função do seu uso para navegação. A interferência de 130 anos de assoreamento do reservatório na potência média mensal fornecida pelo sistema não foi significativa. No entanto, na análise do período de estiagem o assoreamento foi responsável pela redução em 321,90 MWh da energia média mensal excedente produzida, para o nível mínimo de operação de 381,0 m, e em 460,06 MWh, para o nível mínimo de operação de 379,7 m. / The silting of reservoirs formed from the building of dams interferes unavoidably in their useful volumes. The useful volume is the compartment responsible by storing water to supply consumptive and not-consumptive water uses, and its reduction changes the demands supply. In this research, the interference of Promissão reservoir (located in Middle Tietê watershed) silting process in the electric energy generation of Mário Lopes Leão Hydroelectric Power Plant was investigated. The quantification of reservoir silting in the last thirty years of operation was accomplished by the comparison of lake’s original topography in the reservoir filling period, in 1975, with the topobathymetry obtained in 2005. The RESSASS model was used in the analysis of reservoir volume change between 1975 and 2005, and to preview the reservoir silting until the years 2055 and 2105. The loss of reservoir useful volume was 4,31% between 1975 and 2005, reaching 9,59% in 2105. The reservoir silting was also investigated through qualitative analysis of data, identifying influents that present higher degree of silting. The interference of reservoir useful volume variation in the hydropower electricity generation analysis was accomplished by using AcquaNet model. Promissão reservoir was investigated isolately. Simulations were done considering differents stage vs. area vs. volume curves to the years 1975, 2005, 2055, and 2105, besides the consideration of two minimal operational levels: 379,7 m, minimal reservoir level, and 381,0 m, minimal operational level in which the reservoir is operated to allow navigation. The interference of 130 years of reservoir silting in the monthly average provided by the hydropower system was not significant. Nevertheless, in the dry period, silting was responsible by a reduction of 335,69 MWh in the monthly average electricity excess, in the minimal operation level 381,0 m, and 471,16 MWh, in the minimal operation level 379,7 m.

Uma das principais necessidades da célula é a regulação do seu ambiente interno. Aparte da considerável importância teórica, o transporte de água é de importância prática numa ampla gama de processos, desde a proteção de células na preservação criogênica até os efeitos de certos hormônios em alguns tecidos. Virtualmente todas as células são submetidas a transições osmóticas durante o seu período de vida, uma vez que tanto o metabolismo intracelular quanto o transporte por membranas produzem flutuações nas concentrações dos solutos osmoticamente ativos. A regulação de volume celular é um fenômeno ubíquo e permite, às células, manter o seu volume normal. Células submetidas a choques anisosmóticos agudos sofrem rápidas alterações de volume (dependentes do gradiente osmótico e da permeabilidade da membrana à água e osmólitos) podendo ou não ser seguidas de lentas alterações regulatórias de volume. Assim, o objetivo do presente trabalho visou esclarecer alguns aspectos do transporte de água em células de melanoma murino S91 submetidas a condições anisosmóticas. Células de melanoma murino S91, foram mantidas em meio de cultura F12 HAM (290 mOsm.kgH2O-1). As medidas morfométricas das mudanças relativas de volume foram realizadas usando-se um sistema de aquisição e análise de imagens (Image Pro-Lite, Media Cybernetics). As células foram expostas tanto a choques hiposmóticos agudos (190 mOsm.kgH2O-1) como a choques hiperosmóticos agudos (350 mOsm.kgH2O-1) em diferentes temperaturas (de 17 a 37 oC) e em diferentes doses (de 0,001 a 1000 µM) de HgCl2, um bloqueador de aquaporinas (AQP). Os resultados sugerem que: (i) o tempo de regulação de volume em células de melanoma murino S91 é dependente da temperatura; (ii) o fluxo osmótico de água apresenta valores de Energia de Ativação compatíveis com aqueles propostos para o trânsito de água através de aquaporinas (Ea < 6 kcal.mol-1); (iii) o HgCl2 afeta de forma dose dependente as respostas osmóticas em células de melanoma murino S91 e sugerem a presença de mais de um tipo de AQP. Nestas condições as concentrações necessárias para reduzir ao máximo a permeabilidade osmótica à água estão localizadas na faixa de 0,1-1,0 µM HgCl2. / One of the major needs of living cells is the regulation of their internal environment. Apart from being of considerable theoretical importance, the transport of water is of practical importance in a broad range of process, from the protection of cells undergoing cryogenic preservation to the effects of certain hormones in some tissues. Virtually all the cells are submitted the osmotic transitions during their period of life, because both intracellular metabolism and transmembrane transport produce fluctuations in concentrations of osmolytes. The regulation of cellular volume is a phenomenon ubiquitous and allows, to the cells, to keep their normal volume. Cells subjected to acute anisosmotic shocks suffer from fast alterations in volume (depending on the osmotic gradient and on the permeability of the membrane to the water and osmotically active substances), and followed or not by a slow volume regulation response. Thus, the present work aims to clarify some aspects of the water transport in murine melanoma S91 cells subjected to anisosmotic conditions. S91 murine melanoma cells were grown in F12 HAM medium (290 mOsm.kgH2O-1). Morphometric measurements of relative changes in cell volume were performed using a video microscopy system and a PC software (Image Pro-Lite, Media Cybernetics). The experimental cells were exposed either to acute hyposmotic shocks (190 mOsm.kgH2O-1) or to acute hyperosmotic shocks (350 mOsm.kgH2O-1), in different temperatures (ranging from 17 to 37 oC) and in the presence of HgCl2 (from 0,001 to 1000 µM), an aquaporin blocker. The results of the present study indicate that: (i) the time of volume regulation in S91 murine melanoma cells is dependent on temperature; (ii) the values of osmotic water flow are compatible with activation energy through aquaporins (E < 6 kcal.mol-1) and (iii) HgCl2 treatments affect osmotic behavior of S91 murine melanoma cells in a dose-response manner and also suggest the presence of more than one type of aquaporin. Minimum osmotic water permeabilities were observed in a range of µM HgCl2 treatments.

O objetivo desse estudo foi verificar o efeito de diferentes volumes de treinamento de força na força máxima de membros inferiores e na hipertrofia do reto femoral e do vasto lateral após quatro, oito e doze semanas em indivíduos treinados em força. Vinte e seis indivíduos jovens saudáveis do sexo masculino (idade 23,6 ± 4,6 anos, massa corporal 76,6 ± 7,5 kg, estatura 1,75 ± 0,1 cm), com tempo médio de treinamento de força (4,7 ± 4,1 anos) foram divididos em três grupos experimentais, treinamento de força alto volume (TFAV, n = 8), treinamento de força médio volume (TFMV, n = 9) e treinamento de força baixo volume (TFBV, n = 9). As medidas de força dinâmica máxima (1RM) e de área de secção transversa muscular (ASTM) do reto femoral (RF) e do vasto lateral (VL) foram realizadas nos momentos pré- treinamento, pós quatro semanas, pós oito semanas e pós-treinamento. O volume total de treinamento apresentou aumento estatístico para todos os grupos TFAV (p < 0,0001), TFMV (p < 0,0001) e TFBV (p < 0,0001) ao longo do período experimental. Os valores de 1RM aumentaram de maneira significativa após a oitava semana de treinamento TFAV (11,8 ± 4,7%; p < 0,0001) e TFMV (12,1 ± 8,5%; p < 0,0001) e TFBV (9,6 ± 7,3%; p < 0,001) e no pós-treinamento TFAV (13,9 ± 3,9%; p < 0,0001), TFMV (16,7 ± 10,8%; p < 0,0001) e TFBV (14,0 ± 8,1%; p < 0,0001) para todos os grupos, porém não foi observado diferença entre os grupos. A ASTM do RF apresentou aumento estatístico no pós-treinamento somente para o grupo TFAV (15,0 ± 11,9%; p < 0,0001). Apenas o grupo TFAV aumentou estatisticamente a ASTM do VL após quatro semanas de treinamento (7,71 ± 4,42%; p < 0,0001), porém todos os grupos aumentaram significativamente a ASTM do VL após oito semanas de treinamento TFAV (11,37 ± 3,88%; p < 0,0001), TFMV (9,68 ± 9,36%; p < 0,0001) e TFBV (7,26 ± 3,15%; p < 0,01) e no pós-treinamento TFAV (14,54 ± 4,07%; p < 0,0001), TFMV (14,77 ± 8,24%; p < 0,0001) e TFBV (8,66 ± 3,97%; p < 0,001), porém não foi observado diferença entre os grupos. Os resultados do presente estudo demonstraram que, independente do volume adotado, os ganhos de força máxima foram semelhantes. Por outro lado, a ASTM foi influenciada pelo volume de treinamento, dado que o grupo TFAV foi o único que apresentou aumento significativo da ASTM do RF no pós-treinamento e aumentou a ASTM do VL com apenas quatro semanas de treinamento / The aim of this study was to investigate the effects of different strength training volumes on muscle strength and hypertrophy of the lower limbs after four, eight and twelve weeks of strength training in strength-trained individuals. Twenty-six healthy young males (age 23.6 ± 4.6 years, body mass 76.6 ± 7.5 kg, height 1.75 ± 0.1 cm), with an average experience of strength training (4.7 ± 4.1 years) were divided into three groups, high-volume strength training (TFAV, n = 8), mid-volume strength training (TFMV, n = 9) and low-volume strength training (TFBV, n = 9). Maximum dynamic strength (1RM) and muscle cross-sectional area (MCSA) of the rectus femoris (RF) and vastus lateralis (VL) were measured at baseline, after four weeks, after eight weeks and post-training. The total training volume significantly increased for the groups TFAV (p < 0.0001), TFMV (p < 0.0001) and TFBV (p < 0.0001) throughout the experimental period. The 1RM values increased after the eighth weeks of training, compared to baseline values, for the TFAV (11.8 ± 4.7%; p < 0.0001), TFMV (12.1 ± 8.5%; p < 0.0001), and TFBV (9.6 ± 7.3%; p < 0.001) groups, and post-training TFAV (13.9 ± 3.9%; p < 0.0001), TFMV (16.7 ± 10.8%; p < 0.0001) and TFBV (14.0 ± 8.1%; p < 0.0001) for all groups, with no difference between groups. Only TFAV group presented higher RF MCSA values at post-training (15.0 ± 11.9%; p < 0.0001). Furthermore, only TFAV significantly increased the VL MCSA after four weeks of training (7.71 ± 4.42%; p < 0.0001). All of the groups presented significantly greater VL MCSA than baseline values at eight weeks TFAV (11.37 ± 3.88%; p < 0.0001), TFMV (9.68 ± 9.36%; p < 0.0001) and TFBV (7.26 ± 3.15%; p < 0.01) and at post-training TFAV (14.54 ± 4.07%; p < 0.0001), TFMV (14.77 ± 8.24% ; p < 0.0001) and TFBV (8.66 ± 3.97%; p < 0.001), with no difference between groups. The results of this study demonstrated that, regardless of the adopted volume, the muscle strength gains were similar. On the other hand , MCSA was influenced by the training volume, since the TFAV was the only group that showed significant increase of RF MCSA post- training and increased VL MCSA with only four weeks of training