Effect of the Heating Block Position on Natural Convection in a Three-Dimensional Cavity Filled with Nanofluids

This paper consists on a three-dimensional numerical approach of natural convection in a cavity containing the nanofluid. The cavity contains an isothermal heating block in the middle of the bottom (case BH) and the top (case TH) walls and kept at a hot temperature TH. The right and the left vertical walls of the cavity are kept at a cold temperature Tc. The study's parameters are: the volume fraction Ф varying between 0 and 0.03, and the Rayleigh number . The considered nanofluid is water + Cu. The results illustrate that the Rayleigh number Ra and the volume fraction Ф have a positive effect and they also improve the heat transfer. Interesting results have also been found while comparing the two considered configurations

The effect of pramipexole extended release on the levodopa equivalent daily dose in Lebanese Parkinson diseased patients

Objective: The objective of this study is to compute the potential benefit of Pramipexole ER on total levodopa equivalent dose (LED) and Unified Parkinson Disease Rating Score (UPDRS-III) compared to mono- or combined therapy of pramipexole IR and/or carbidopa/levodopa. Methods: This is a retrospective observational study conducted in a specialized PD (Parkinson Disease) and movement disease center in Lebanon between January and December 2017. Results: A total of 176 patient’s record was reviewed. Pramipexole ER showed a significant difference on the mean changes in LED and UPDRS-III score. After 13 weeks of initiating Pramipexole ER, the mean decrease in LED was -49.42 mg for all patients (p < 0.001, CI 95% [35.28-63.55]) and the mean decrease in UPDRS-III score for all patients was -6 points (P< 0.001). According to the subgroup analysis, patients aged 65 years and below, the change in mean total LED from baseline ( 350.80 mg) was a decrease of 63.19 mg with a p<0.001, CI 95% [42.07-84.31]. In patients aged more than 65 years and shifted to mono or combined pramipexole ER therapy, the change in mean total LED from baseline (559.25 mg) was a decrease of 34.67 mg with a p<0.001 CI 95% [16.16-53.18]. In addition the results showed that in patients having an UPDRS-III score of less than or equal to 33, the change in mean total LED from baseline (436.73 mg) was a decrease of 56.76 mg (p<0.001; CI 95% [41.32-72.20]). However, in patients having an UPDRS-III score of more than 33 the change in mean total LED from baseline (545.06 mg) was a decrease of 2.96 mg with a p value < 0.844 CI 95% [27.32-33.15]. Conclusions: This study demonstrated the efficacy of Pramipexole ER on decreasing the total levodopa equivalent dose (LED).The role of health care professionals is to maintain the patient on the lowest effective levodopa equivalent daily dose and optimize the treatment therapy, thus decreasing the side effects that might arise from overdosing of antiparkinsonian drugs

Contribution des isotopes de l’environnement pour la comprehension du fonctionnement de l’aquifere mio-plioquaternaire du Haouz de Marrakech (Maroc)

The study area &laquo;Haouz plain&raquo; is Located at the center of Morocco, it extend on a surface of 2800 km2, limited by the Jbilet hills in the North, the High-Atlas range in the South, R' dat wadi in the East and the Essaouira-Chichaoua plateau in the West. The area climate is semi-arid, characterized by low precipitations varying between 160 mm/year and 250mm/year and important variation in temperature between the winter and the summer with respectively 5&deg;C and 45&deg;C. Its hydrographic network is represented by the Tensift system which receives all the affluents of central and Westem Haouz. These affluents are characterized by weak flows with important seasonal variations. The Haouz plain is a sedimentary basin, being along the northern edge of the high atlas, it presents a geologic succession going from the primary to the recent Quaternary. The mio-plioquatemary formations, stemming from the dismantling of the atlasic chain, refuge an important and generalized water table on al1 the plain. This water table shows very variable hydrodynarnic characteristics, reflecting the complexity of the deep structures of the plain, 1986) and also the lithological variability of the mio-plioquatemary formations. The Haouz plain includes also the deep resemoirs of the Jurassic, Cretaceous and Eocene which finish some meters at the north of the Atlas, thus having a very limited extension and thereafter a low productivity. Five representative samples of water taken on the haouz water table were analyzed by the ABHT, the projection of these contents on the potability diagram enabled us to show that water of the water table generally has a good quality to passable. In the east quality becomes poor related to the existence of a zone arranged for agriculture (piezometer 1903/44). The nastiest potability is obsemed on the piezometer 3828/44 located at north of Marrakech at elazouzia zone of spreading of wom water of this city. The representation of the percentages of anions and major cations shows the prevalence of ions Ca2+ and HCO; and makes it possible to show up the Bicarbonate calcic facies of the water table. During these last decades, the use of stable isotopes, such oxygen 18 and deuterium, became necessary for the study of subsoil waters, it makes possible the estimation of the surfaces of refills, the determination of water origin. The samples taken on water points well distributed in the area of study allowed us a better comprehension of the function of the plioquatemary water table. The relation oxygen 18, deuterium shows that water is aligned on a line of slope 8.09, slightly different from the world meteoric line, thus characterizing precipitations of oceanic origin which did not endure notable isotopic fractionation therefore not important evaporation. Using the isotopic measures for the sarnples taken in January 2002 on wells well distributed in the area of study, allows us to show a variation of the contents of 018 with the altitude of the zones of refill. Thus we could delimit the surfaces of refill between 1500 and 800meters height. The relation oxygen-18 deuterium (&delta;2H = 8,9032 &delta;18O + 14,214 (R2 = 0,7449 ) translated an Atlantic mode of precipitations without remarkable evaporation.Parmi les aquif&egrave;res r&eacute;gionaux importants de tr&egrave;s grande extension au Maroc, celui du Haouz qui s&rsquo;&eacute;tend sur une superficie de 6.000 km2, circule au niveau du remplissage mioplioquaternaire issue du d&eacute;mant&egrave;lement de la cha&icirc;ne Atlasique. Ce dernier pr&eacute;sente un faci&egrave;s constitu&eacute; de galets, graviers, argiles, marnes et calcaires, dont la puissance atteint les 100 m&egrave;tres. Cet aquif&egrave;re joue un r&ocirc;le tr&egrave;s important dans l&rsquo;alimentation en eau potable des habitants de la plaine du Haouz d&rsquo;une population de plus de 4 millions d&rsquo;habitants, en sus d&rsquo;un compl&eacute;ment a l&rsquo;irrigation de 80.000 ha. Le climat aride de type continental, qui y r&egrave;gne se caract&eacute;rise par des amplitudes thermiques assez importantes entre l&rsquo;hiver et l&rsquo;&eacute;t&eacute;. La pluviom&eacute;trie pr&eacute;sente une moyenne de 250 mm par an. La pi&eacute;zom&eacute;trie de la zone &eacute;tudi&eacute;e est caract&eacute;ris&eacute;e par un &eacute;coulement g&eacute;n&eacute;ral du sud vers le nord ouest en direction de l&rsquo;oued Tensift, &eacute;galement principal collecteur des eaux de surface de la r&eacute;gion. Une campagne de mesures isotopiques de plus d&rsquo;une vingtaine d&rsquo;&eacute;chantillons pr&eacute;lev&eacute;s en janvier 2002 au niveau de puits bien r&eacute;partis dans la zone d&rsquo;&eacute;tude, au pu montrer une variation des teneurs en O&quot; avec l&rsquo;altitude des zones de recharge. En outre, la relation oxygene-18 deut&eacute;rium (&delta;2H = 8,9032 &delta;18O + 14,214 (R2 = 0,7449 traduit un r&eacute;gime atlantique des pr&eacute;cipitations, sans &eacute;vaporation, ce qui implique que la recharge se fait rapidement, probablement a travers les formations mioc&egrave;nes gr&eacute;seuses largement fissur&eacute;es a l&rsquo;affleurement de l&rsquo;aquif&egrave;re m&iacute;o-plioquatemaire. Un gradient altitudinal moyen de -0,26 &permil; par 100 m&egrave;tres est d&eacute;termin&eacute; pour la plaine du Haouz, tr&egrave;s proche des autres valeurs trouv&eacute;es pour d&rsquo;autres r&eacute;gions au Maroc, confirmant la validit&eacute; r&eacute;gionale de celui-ci. Les variations des teneurs en oxygene-18 peuvent &ecirc;tre interpr&eacute;t&eacute;es en termes de diff&eacute;rence d&rsquo;altitude entre les altitudes de recharge et d&rsquo;&eacute;mergence

Estimation of molecular and thermodiffusion coefficients for non‐ideal molten metal alloys and its implication in solidification process

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/107525/1/cjce21972.pd

Numerical Simulation of the Natural Convection with Presence of the Nanofluids in Cubical Cavity

This article consists of a numerical study of natural convection heat transfer in three-dimensional cavity filled with nanofluids. This configuration is heated by a partition maintained at a hot constant and uniform temperature TH. The right and left vertical walls are kept at a cold temperature TC while the rest is adiabatic. The fluid flow and heat transfer in the cavity are studied for different sets of the governing parameters, namely, the nanofluid type, the Rayleigh number Ra = 103, 104, 105, and 106, and the volume fraction Ф varying between Ф = 0 and 0.1. The obtained results show a positive effect of the volume fraction and the Rayleigh number on the heat transfer improvement. The analysis of the results related to the heat transfer shows that the copper-based nanofluid guarantees the best thermal transfer. In addition, the increase of the heating section size and Ra leads to an increased amount of heat. Similarly, increasing the volume fraction improves the intensification of the flow and increases the heat exchange