992 resultados para Corporal Strength
Resumo:
Objectives: To examine the association between fruit and vegetable (FV) consumption and muscle strength and power in an adolescent population. Methods: We conducted a cross-sectional analysis among 1019 boys and 998 girls, aged 12 and 15 years, who participated in The Young Hearts Project. FV consumption (excluding potatoes) was assessed by 7-d diet history. Grip strength and jump power was assessed with a dynamometer and Jump-MD meter, respectively. Associations between FV consumption and strength and power were assessed by regression modelling. Results: Boys and girls with the highest FV intakes (>237.71 g/d and >267.57 g/d, respectively, based on the highest tertile) had significantly higher jump power than those with the lowest intakes (<135.09 g/d and <147.43 g/d, respectively), after adjustment for confounding factors. Although girls with the highest FV intakes had higher grip strength than those with the lowest intakes, no significant independent associations were evident between FV intake and grip strength in boys or girls. Similar findings were observed when FV were analysed separately.Conclusions: Higher FV consumption in this group of adolescents was positively associated with muscle power. There was no independent association between higher FV consumption and muscle strength. Intervention studies are required to determine whether muscle strength and power can be improved through increased FV consumption.
Resumo:
Social identity in Northern Ireland is multifaceted, with historical, religious, political, social, economic, and psychological underpinnings. Understanding the factors that influence the strength of identity with the Protestant or Catholic community, the two predominate social groups in Northern Ireland, has implications for individual well-being as well as for the continuation of tension and violence in this setting of protracted intergroup conflict. This study examined predictors of the strength of in-group identity in 692 women (mean age 37 years) in post-accord Northern Ireland. For Catholics, strength of in-group identity was positively linked to past negative impact of sectarian conflict and more frequent current church attendance, whereas for Protestants, strength of in-group identity was related to greater status satisfaction regarding access to jobs, standard of living, and political power compared with Catholics; that is, those who felt less relative deprivation. The discussion considers the differences in the factors underlying stronger identity for Protestants and Catholics in this context.
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The effect of colloidal nanosilica on the fresh and rheological parameters, plastic shrinkage, heat of hydration, and compressive strength of cement-based grouts is investigated in this paper. The fresh and rheological properties were evaluated by the minislump flow, Marsh cone flow time, Lombardi plate cohesion meter, yield value, and plastic viscosity. The key parameters investigated were the dosages of nanosilica and superplasticizer and temperature of mixing water. Statistical models and isoresponse curves were developed to capture the significant trends. The dosage of nanosilica had a significant effect on the results. The increase in the dosage of nanosilica led to increasing the values of flow time, plate cohesion meter, yield stress, plastic viscosity, heat of hydration at 1 day and 3 days, and compressive strength at 1 day, while reducing the minislump, plastic shrinkage up 24 h, and compressive strength at 3, 7, and 28 days. Conversely, the increase in the dosage of superplasticizer led to decreasing the values of flow time, plate cohesion meter, yield stress, plastic viscosity, heat of hydration at 1 day and 3 days, and compressive strength at 1 day, while increasing the minislump, plastic shrinkage, and compressive strength at 3 and 7 days. Increasing the temperature of mixing water led to a notable increase in the results of minislump, flow time, plastic viscosity, heat of hydration at 3 days, and compressive strength at 1 day, while it reduced the plate cohesion, compressive strength at 3, 7, and 28 days. The statistical models developed in this study can facilitate optimizing the mixture proportions of grouts for target performance by reducing the number of trial batches needed.
Resumo:
The overall aim of the project was to study the influence of process variables on the distribution of a model active pharmaceutical ingredient (API) during fluidised melt granulation of pharmaceutical granules with a view of optimising product characteristics. Granules were produced using common pharmaceutical excipients; lactose monohydrate using poly ethylene glycol (PEG1500) as a meltable binder. Methylene blue was used as a model API. Empirical models relating the process variables to the granules properties such as granule mean size, product homogeneity and granule strength were developed using the design of experiment approach. Fluidising air velocity and fluidising air temperature were shown to strongly influence the product properties. Optimisation studies showed that strong granules with homogeneous distribution of the active ingredient can be produced at high fluidising air velocity and at high fluidising air temperatures.
Resumo:
Microstructure, tensile properties and fractography have been examined in the oil-quenched samples of a low-alloy ultrahigh strength 4340 steel. Intergranular fracture was revealed to locate at the fracture origin. However, neither the quenched Charpy V-notched impact samples nor the tempered tensile samples showed such intergranular fracture behavior. The effects of loading rate and precipitation are discussed.
Resumo:
Bonded-in rod connections in timber possess many desirable attributes in terms of efficiency, manufacture, performance, aesthetics and cost. In recent years research has been conducted on such connections using fibre reinforced polymers (FRPs) as an alternative to steel. This research programme investigates the pull-out capacity of Basalt FRP rods bonded-in in low grade Irish Sitka Spruce. Embedded length is thought to be the most influential variable contributing to pull- out capacity of bonded-in rods after rod diameter. Previous work has established an optimum embedded length of 15 times the hole diameter. However, this work only considered the effects of axial stress on the bond using a pull-compression testing system which may have given an artificially high pull out capacity as bending effects were neglected. A hinge system was utilised that allows the effects of bending force to be taken in to consideration along with axial forces in a pull-out test. This paper describes an experimental programme where such pull-bending tests were carried out on samples constructed of 12mm diameter BFRP bars with a 2mm glueline thickness and embedded lengths between 80mm and 280mm bonded-in to low-grade timber with an epoxy resin. Nine repetitions of each were tested. A clear increase in pull-out strength was found with increasing embedded length.
Resumo:
Small mixer impeller design is not tailored for granulation because impellers are intended for a wide range of processes. The aim of this research was to evaluate the performances of several impellers to provide guidance on the selection and design for the purposes of granulation. Lactose granules were produced using wet granulation with water as a binder. A Kenwood KM070 mixer was used as a standard apparatus and five impeller designs with different shapes and surface areas were used. The efficacy of granulate formation was measured by adding an optically sensitive tracer to determine variations in active ingredient content across random samples of granules from the same size classes. It was found that impeller design influenced the homogeneity of the granules and therefore can affect final product performance. The variation in active ingredient content across granules of differing size was also investigated. The results show that small granules were more potent than larger granules.
Resumo:
Aim. To investigate (a) variability in powder/liquid proportioning and (b) effect of variability on diametral tensile strength (DTS), in a zinc phosphate cement. Statistical analyses (α = 0.05) were by Student's t-test in the case of powder/liquid ratio and one-way ANOVA and Tukey HSD for pair-wise comparisons of mean DTS. The Null hypotheses were that (a) the powder-liquid mixing ratios would not differ from the manufacturer's recommended ratio (b) DTS of the set cement samples using the extreme powder/liquid ratios would not differ from those made using the recommended ratio.
Methodology. 34 dental students dispensed the components according to the manufacturer's instructions. The maximum and minimum powder/liquid ratios, together with the manufacturer's recommended ratio, were used to prepare samples for DTS testing.
Results. Powder/liquid ratios ranged from 2.386 to 1.018. The mean ratio (1.644) was not significantly different from the recommended value of 1.718 (P = 0.189). DTS values for the maximum and minimum ratios were both significantly different from each other (P < 0.001) and from the mean value obtained from the recommended ratio (P < 0.001).
Conclusions. Variability exists in powder/liquid ratio for hand dispensed zinc phosphate cement. This variability can affect the DTS of the set material.
Resumo:
Low-velocity impact damage can drastically reduce the residual mechanical properties of the composite structure even when there is barely visible impact damage. The ability to computationally predict the extent of damage and compression after impact (CAI) strength of a composite structure can potentially lead to the exploration of a larger design space without incurring significant development time and cost penalties. A three-dimensional damage model, to predict both low-velocity impact damage and compression after impact CAI strength of composite laminates, has been developed and implemented as a user material subroutine in the commercial finite element package, ABAQUS/Explicit. The virtual tests were executed in two steps, one to capture the impact damage and the other to predict the CAI strength. The observed intra-laminar damage features, delamination damage area as well as residual strength are discussed. It is shown that the predicted results for impact damage and CAI strength correlated well with experimental testing.
Resumo:
This paper considers inference from multinomial data and addresses the problem of choosing the strength of the Dirichlet prior under a mean-squared error criterion. We compare the Maxi-mum Likelihood Estimator (MLE) and the most commonly used Bayesian estimators obtained by assuming a prior Dirichlet distribution with non-informative prior parameters, that is, the parameters of the Dirichlet are equal and altogether sum up to the so called strength of the prior. Under this criterion, MLE becomes more preferable than the Bayesian estimators at the increase of the number of categories k of the multinomial, because non-informative Bayesian estimators induce a region where they are dominant that quickly shrinks with the increase of k. This can be avoided if the strength of the prior is not kept constant but decreased with the number of categories. We argue that the strength should decrease at least k times faster than usual estimators do.
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This article examines the evaluative nature of the folk concepts of weakness and strength of will and hypothesizes that their evaluative nature is strongly connected to the folk concepts of blame and credit. We probed how people apply the concepts of weakness and strength of will to prototypical and non-prototypical scenarios. While regarding prototypical scenarios the great majority applied these concepts according to the predictions following from traditional philosophical analyses, when presented with non-prototypical scenarios, people were divided. Some, against traditional analyses, did not apply these concepts, which we explain in terms of a clash of evaluations involving different sorts of blame and credit. Others applied them according to traditional analyses, which we explain in terms of a disposition to be reflective and clearly set apart the different sorts of blame and credit involved. Still others applied them in an inverse way, seemingly bypassing the traditional components resolution and best judgment, which we explain in terms of a reinterpretation of the scenarios driven by an assumption that everyone knows deep inside that the best thing to do is to act morally. This division notwithstanding, we claim that our results are largely supportive of traditional analyses (qua analyses of folk concepts).
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Highly efficient In2O3-Co3O4 catalysts were prepared for ultralow-temperature CO oxidation by simultaneously tuning the CO adsorption strength and oxygen activation over a Co3O4 surface, which could completely convert CO to CO2 at temperatures as low as -105 degrees C compared to -40 degrees C over pure Co3O4, with enhanced stability.
Resumo:
Objectives: To quantify variability in hand proportioning of zinc phosphate cement among a cohort of dental undergraduates and to determine the effect of any such variability on the diametral tensile strength (DTS) of the set cement. The null hypothesis was that such variability has no effect on DTS.
Methods: Thirty-four operators dispensed a zinc phosphate cement [Fleck's® Cement] according to the manufacturers' instructions. The mass of powder and liquid dispensed was recorded. Cylindrical specimens (n = 2 x 34) of dimensions 6mm x 3mm were prepared using a stainless steel split mould. The maximum mass of powder and the minimum volume of liquid were used as one extreme ratio and the minimum mass of powder and the maximum volume of liquid used on the other extreme. The manufacturers' recommended ratio was also tested (n=34).The samples were left to set for one hour before being transferred into distilled water for 48 hours. Compression across a diameter was carried out using a universal testing machine, H10KS [Tinius Olsen], at a constant crosshead speed of 0.75 ±0.25 mm/min. Statistical analyses (α = 0.05) were by Student's t-test for the powder/liquid ratio and one-way ANOVA and Tukey HSD for for pair-wise comparisons of mean DTS. Tests were carried out for normality and constant variability.
Results: The mean (range) amount of powder dispensed was 0.863g (0.531-1.216)g. The mean (range) amount of liquid dispensed was 0.341ml (0.265-0.394)ml. The manufacturer's recommended amounts were 0.8g of powder and 0.3ml of liquid. The mean powder/liquid ratio was not significantly different from the manufacturer's recommended value (p=0.64). Mean (SD) DTS were (MPa) max: 7.19(1.50), min: 2.65(1.01), manufacturer: 6.01(1.30). All pair-wise comparisons were significantly different (p<0.001).
Conclusions: Variability exists in the hand proportioning powder and liquid components of zinc phosphate cement. This variability can affect the DTS of zinc phosphate cement.
Resumo:
Low-velocity impact damage can drastically reduce the residual mechanical properties of the composite structure even when there is barely visible impact damage. The ability to computationally predict the extent of damage and compression after impact (CAI) strength of a composite structure can potentially lead to the exploration of a larger design space without incurring significant development time and cost penalties. A three-dimensional damage model, to predict both low-velocity impact damage and compression after impact CAI strength of composite laminates, has been developed and implemented as a user material subroutine in the commercial finite element package, ABAQUS/Explicit. The virtual tests were executed in two steps, one to capture the impact damage and the other to predict the CAI strength. The observed intra-laminar damage features, delamination damage area as well as residual strength are discussed. It is shown that the predicted results for impact damage and CAI strength correlated well with experimental testing.