Experimental and Numerical Investigation of Heat Transfer Augmentation Using Al2o3-Ethylene Glycol Nanofluids Under Turbulent Flows in a Flat Tube

A study of computational fluid dynamics has been conducted to study the characteristics of the heat transfer and friction factor of Al2O3/Ethylene glycol-water nanofluid flowing inside flat tube. The three dimensional realizable k?e turbulent model with an enhanced wall treatment was utilized. The evaluation of the overall performance of the tested tube was predicated on the thermo-hydrodynamic performance index. The obtained results showed that the difference in behaviour depending on the parameter that has been selected to compare the nanofluid with the base fluid. In addition, the friction factor and the heat transfer coefficient increases with an increase of the nanoparticles volume concentration at the same Reynolds number. The penalty of pressure drop is negligible with an increase of the volume concentration of nanoparticles. Conventional correlations that have been used in turbulent flow regime to predict average heat transfer and friction factor are Dittus-Boelter and Blasius correlations, for tubes are also valid for the tested nanofluids which consider that the nanofluids have a homogeneous fluid behaviour

Flexural behavior of concrete beams reinforced with different types of fibers

Enhanced tensile properties of fiber reinforced concrete make it suitable for strengthening of reinforced concrete elements due to their superior corrosion resistance and high tensile strength properties. Recently, the use of fibers as strengthening material has increased motivating the development of numerical tools for the design of this type of intervention technique. This paper presents numerical analysis results carried out on a set of concrete beams reinforced with short fibers. To this purpose, a database of experimental results was collected from an available literature. A reliable and simple three-dimensional Finite Element (FE) model was defined. The linear and nonlinear behavior of all materials was adequately modeled by employing appropriate constitutive laws in the numerical simulations. To simulate the fiber reinforced concrete cracking tensile behavior an approach grounded on the solid basis of micromechanics was used. The results reveal that the developed models can accurately capture the performance and predict the load-carrying capacity of such reinforced concrete members. Furthermore, a parametric study is conducted using the validated models to investigate the effect of fiber material type, fiber volume fraction, and concrete compressive strength on the performance of concrete beams

The Canadian Healthy Infant Longitudinal Development (CHILD) birth cohort study: Assessment of environmental exposures

The Canadian Healthy Infant Longitudinal Development birth cohort was designed to elucidate interactions between environment and genetics underlying development of asthma and allergy. Over 3600 pregnant mothers were recruited from the general population in four provinces with diverse environments. The child is followed to age 5 years, with prospective characterization of diverse exposures during this critical period. Key exposure domains include indoor and outdoor air pollutants, inhalation, ingestion and dermal uptake of chemicals, mold, dampness, biological allergens, pets and pests, housing structure, and living behavior, together with infections, nutrition, psychosocial environment, and medications. Assessments of early life exposures are focused on those linked to inflammatory responses driven by the acquired and innate immune systems. Mothers complete extensive environmental questionnaires including time-activity behavior at recruitment and when the child is 3, 6, 12, 24, 30, 36, 48, and 60 months old. House dust collected during a thorough home assessment at 3–4 months, and biological specimens obtained for multiple exposure-related measurements, are archived for analyses. Geo-locations of homes and daycares and land-use regression for estimating traffic-related air pollution complement time-activity-behavior data to provide comprehensive individual exposure profiles. Several analytical frameworks are proposed to address the many interacting exposure variables and potential issues of co-linearity in this complex data set