غفران محمد جاسم محمد, قاسم كرم عبدالله

كلية الهندسة-جامعة بابل · العراق

Adjoudj Réda , Leila Zoubida, Feraoun M. Kamel

كلية العلوم الدقيقة-جامعة جيلالي ليابس – سيدي بلعباس · الجزائر

Fouad Azizi, Sahar Mousa Ataya

كلية مارون سمعان للهندسة والعمارة-الجامعة الأمريكية في بيروت · لبنان

To improve mixing quality and thermal homogeneity in small scale industrial applications involving viscous fluids, different microstructures have been designed. Split-and-Recombine (SAR) microstructures are one of the designs that have been extensively studied due to their compactness and efficiency. The current work is a numerical study that describes the mixing, hydrodynamic and thermal performance of a new SAR geometry design used as a multifunctional heat exchanger. This new design utilizes double separation and recombination to achieve good mixing and heat transfer in a very compact structure. For this purpose, computational fluid dynamics tools were used to compute and assess mixing indices, pressure drop, friction factor, and thermal homogenization for a viscous fluid at different flow conditions. The findings were compared against two commonly used SAR mixers in the literature in the Reynolds range of 1 to 300. The results show that for Re99%. On the other hand, the thermal-hydraulic performance of the Double SAR was lower yet close to that of Gray SAR (with difference ranging between 19 % and 25%). Nonetheless, it was superior to the thermal- hydraulic performance of Chen SAR (with difference ranging between 70 % and 85%). Hence, the new Double SAR design has proved to offer a balance performance: achieving both good mixing quality and thermal homogenization at low energy expenditure.

Ashraf N. AlKhateeb, Kursat Kara, Shadi Balawi, Shamma Al Hemeiri

جامعة خليفة · الامارات

This study encompasses the structural analysis of an external aerial pod. The pod's shell constructed from sandwich panel with an arc-tan corrugation. The homogenization technique is employed to find the equivalent effective elastic properties of the pod's sandwich panel structure. Using Euler-Bernoulli beam theory, the sandwich panel structure is mechanically reduced via describing its behavior with five in-plane elastic properties. The energy approach and unit load method are utilized to homogenize the sandwich panel. The model is verified via comparing it against available data in the literature. Also, the validation study conducted on the model shows good agreement with theoretical results. The homogenized model is optimized in which the number of variables in the model is reduced by 50%. In addition, to minimize the drag, a two-dimensional aerodynamics analysis is numerically performed using ANSYS - Fluent to optimize geometrically the designed pod.

K. Chebbah, Nour El Houda Laala, R. Baghdad

كلية علوم المادة-جامعة ابن خلدون – تيارت · الجزائر

حمد بن عبد الله السويلم, عبد العزيز بن عبد الرحمن الصالح

كلية الدراسات العليا-جامعة نايف العربية للعلوم الأمنية · السعودية

Nathan Townsend, Youmna Elsayed Hassanein

كلية العلوم الصحية والحيوية-جامعة حمد بن خليفة · قطر

The maximum fat oxidation rate (MFO) has been suggested to provide useful information regarding endurance training status in athletes, but also as an index of metabolic health in untrained populations. Training in hypoxia is a popular method used by athletes for the purpose of performance enhancement and is emerging as a therapeutic intervention to improve cardiometabolic health. It is known that the addition of hypoxia to exercise induces a shift towards carbohydrate utilization, however the few studies that examined fat oxidation in hypoxia reported equivocal results. This may be due to differences in the methods used to normalize relative intensity. The aim of this study was to evaluate MFO in normoxia (NORM) and hypoxia (HYPO) during exercise at intensities matched relative to the respiratory compensation point (RCP). Methods Seventeen recreationally active adults (5 females/12 males; age: 36.2 ± 7.4 year; body mass: 76.6 ± 13.1 kg) performed a ramp and a step incremental test, in NORM (The fraction of inspired oxygen; FiO2 ≈ 21%) and HYPO (FiO2 ≈ 13.5%), on separate days. The gas exchange threshold (GET), RCP, and the maximum volume of oxygen consumption (V̇O2max) were determined from the ramp tests. The step test involved 6 constant load stages (4-8 minutes) matched for intensity relative to the RCP in each condition. Indirect calorimetry was used to estimate MFO rate during the step test. Each participant’s diet, fasting hours, and testing time were consistent between conditions. Paired t-tests and a 2-way ANOVA were used to examine differences between NORM and HYPO. Pearson correlation was used to assess the relationship between MFO and GET.

حسين المحمود, محمد سامر القصار

كلية الاقتصاد-جامعة دمشق · سوريا

بدر الزوهري, هشام عاطفي

كلية الطب والصيدلة -جامعة سيدي محمد بن عبدالله - فاس · المغرب

Chergui Nabila, Zizette Boufaida

جامعة الاخوة منتورى - قسنطينة 1 · الجزائر