Experimental study in natural convection

The study of thermal and ventilation parameters, obtained in a transient, laminar solar chimney of reduced dimensions, (1 < m <3) m with a square collector (side = 2m) is presented. Experimental measurements has been made to determine the temperature of the absorber and the fluid in the collector, it is shown that at the entrance of the chimney, the temperature of the absorber decreases slightly while that of the fluid is maintained at a maximum level. Temperature differences were observed up to 32°C between the atmosphere and the fluid in April. A temperature variation at the absorber depending on the stack height is presented. Temperature measurements in the chimney, at various heights depending on the axial coordinate, show a variable temperature profile. It is, from these, shown that, in the selected interval of stack height, the average speeds of output increase linearly as a function of stack height. For a chimney of 3m in height and 20cm in diameter, a maximum speed of approximately 0.7 ms-1 was observed. The lack of appropriate equipment handicaps the velocity measurement at the chimney entrance. Thus, the results of simulations with the computer code COMSOL 5.1 has confirmed temperature values measured at the chimney entrance and after this, velocity values are determined.KEYWORDS: 1- Solar chimney, 2- Laminar convection, 3- Temperature, 4- Outlet velocit

Inheritance of fresh seed dormancy in Spanish-type peanut (Arachis hypogaea L.): bias introduced by inadvertent selfed flowers as revealed by microsatellite markers control

Production and seed quality in peanut (Arachis hypogaea L.) can be reduced substantially by in situ germination under unpredictable rainfed environments. Inheritance of fresh seed dormancy in Spanish x Spanish crosses was studied with two sets of segregating populations, an F2 population derived from true F1 hybrids identified with peanut microsatellites markers and other populations (F2, BC1P1S and BC1P2S) from randomly-selected F1 individuals. In the F2 population developed with true F1 hybrids, the chi square test was not significant for the deviation from the expected 3:1 (dormant: non-dormant) ratio. In addition, the bimodal frequency distribution curve with the F2 population gave more evidence that fresh seed dormancy is controlled by a single dominant gene. The average frequency (48%) of true F1 hybrids give evidence that deviations from expected ratios in the populations (F2 and BC1P1S) developed from non-tested F1 individuals, is most likely due to inadvertent selfs. This study emphasized the need to identify with molecular markers the cross progenies in self-pollinated crops as peanutbefore testing for any trait

Optical and Thermal Performance Analysis of a Steady Spherical Collector with a Crescent-shaped Rotating Absorber

In this paper, optical analysis of spherical concentrator is made to determine the local and the global geometric concentration, as knowing the geometric concentration of a system can help predict what temperatures can possibly be obtained with it.This leads to conclude that spherical collectors may produce higher temperatures than parabolic trough, and they could even be sharply improved by using a mixt cylindrical and cavity (or flat) absorber. A craft prototype of a steady spherical concentrator made with concreteand having a smooth inner surface mapped with mirror tape is presented. Its absorber is made with blacken steel sheets and shaped like a moon crescent to be aligned with the declination plan and to avoid motorization for the tracking of the sun from East to West. Experimental measurements lead to temperatures reaching 686°C on the curve of the least diffusion, and 252°C in the absorber oven-like reservoir. Overall, the resultsuggests higher potentialities of spherical collectors,which also show possibility of use with much reduced tracking system and less vulnerability to bad weather

Etude épidémiologique, clinique et thérapeutique des hydrocèles dans trois districts sanitaires de la région de Sikasso/Mali: Epidemiological, Clinical and Therapeutic Study of Hydroceles in Three Health Districts in the Sikasso Region / Mali

Context and objective. Hydrocele is one of the most common urogenital manifestations of lymphatic filariasis. It is a common cause of enlarged scrotum in the tropics. This study aims to describe the epidemiological, clinical and therapeutic aspects of hydroceles. Methods. This cross-sectional descriptive study of hydroceles in three endemic filarial Sikasso areas in Mali was conducted from November 2017 to December 2018. The variables studied were: frequency of hydrocele, age of patients, duration of evolution, type of anesthesia, surgical technique, volume, operative time and postoperative results. Results. Three hundred fifty-eight patients were operated on in fourteen months. The frequency of hydrocele‘s surgery was 31%. Their average age was 47.1 years old (extremes 4 months and 94 years). The duration of evolution was 10.7 years (extremes 6 months and 21 years). The right side was the most affected with 44.1% followed by the left side with 31.3%. Hydrocele was bilateral in 19%. Local anesthesia (with xylocaine 2%) was used in 88%. All patients underwent a successful vaginal resection. Conclusion. The hydrocele remains a common urological pathology in these endemic areas. The diagnosis is made after a long period of evolution of the disease. Treatment in outpatient surgery is undertaken using local anesthesia. These hydrocele management campaigns should be encouraged to treat the maximum number of patients. Contexte et objectif. L’hydrocèle constitue l’une des manifestations urogénitales les plus fréquentes de la filariose lymphatique. Elle est une cause fréquente de grosse bourse dans les régions tropicales. L’objectif de cette étude est de décrire les aspects épidémiologiques, cliniques et thérapeutiques des hydrocèles. Méthodes. Il s’agissait d’une étude transversale et descriptive sur les hydrocèles, réalisée entre novembre 2017 et décembre 2018 ; dans trois zones endémiques filariennes dans la région de SIKASSO au Mali. Les variables étudiées étaient : la fréquence de l’hydrocèle, l’âge des patients, la durée d’évolution, le type d’anesthésie, la technique chirurgicale, le volume, le temps opératoire et les résultats postopératoires. Résultats. Trois cent cinquante-huit patients ont été opérés en quatorze mois. L’intervention de l’hydrocèle rendait compte de 31% des activités chirurgicales. Leur âge moyen était de 47,1 ans (extrêmes 4 mois et 94 ans). La durée d’évolution était de 10,7 ans (extrêmes de 6 mois et 21 ans). Le testicule droit était le plus touché (44,1 %) suivi du côté gauche (31,3%). L’hydrocèle était bilatérale dans 19 %. L’anesthésie locale à la xylocaïne 2 % a été réalisée dans 88%. La résection vaginale a été réalisée chez tous les patients avec succès. Conclusion. L’hydrocèle reste une pathologie urologique fréquente en zone d’endémie filarienne. Le diagnostic se fait après une longue durée d’évolution de la maladie. Le traitement en chirurgie ambulatoire réalisée sous anesthésie locale a montré des résultats satisfaisants. Ces campagnes de prise en charge de l’hydrocèle sont à encourager pour pouvoir traiter le maximum de patients

Obstetric emergencies in the maternity ward of the Ignace Deen national hospital CHU of Conakry: sociodemographic, therapeutic and maternal fetal prognosis aspects

Background: Despite government efforts to reduce maternal mortality, the risk of a woman dying from obstetric complications is about one in six in the poorest regions of the world compared to one in thirty thousand in North Europe. The objective was therefore to describe the clinical socio-demographic aspects and to establish the maternal and fetal prognosis of obstetric emergencies.Methods: This was a descriptive cross-sectional prospective study over a 6-month period from January 1 to June 30, 2020 carried out at the maternity ward of the Ignace Deen national hospital (Conakry university hospital) in Guinea. The study looked at a continuous series of 662 obstetric emergency cases.Results: The frequency of admission of obstetric emergencies was 22.62%. They concerned young women (29.5 years old) on average, first-time mothers (53.32%), with low income professional activities, evacuated from a peripheral maternity unit (63.14%), no schooling (44.9%), married (92.3%), using the more often a means of public transport (66.5%) and whose pregnancies were poorly monitored (63.9%). Fetal emergencies were dominated by acute fetal distress (91.3%) and maternal emergencies were dominated by hypertensive emergencies (pre-eclampsia and eclampsia 37.44%) followed by hemorrhagic emergencies (last trimester hemorrhage and postpartum hemorrhage 34.34%). Pregnant and parturient women were more frequently admitted to labor (62.7%) and gave birth more frequently by caesarean section (86.70%). the staff reacted promptly to make a treatment decision in 75.5% of cases within fifteen minutes. emergency procedures were performed in less than fifteen minutes in almost all cases (97.4%), specific treatment was carried out in less than an hour in the majority of cases (68.3%). The maternal case fatality rate was 4.1% with the main cause of death being hemorrhagic shock of 51.8%. The stillbirth rate was 17.4%.Conclusions: The anticipation of emergency obstetric care (SOU) and close collaboration between the obstetrician, the anesthesiologist-resuscitator are essential in the management of obstetric emergencies

Determinants of unmet need for family planning in rural Burkina Faso: a multilevel logistic regression analysis

Background: Unmet need for family planning has implications for women and their families, such as unsafe abortion, physical abuse, and poor maternal health. Contraceptive knowledge has increased across low-income settings, yet unmet need remains high with little information on the factors explaining it. This study assessed factors associated with unmet need among pregnant women in rural Burkina Faso. Method: We collected data on pregnant women through a population-based survey conducted in 24 rural districts between October 2013 and March 2014. Multivariate multilevel logistic regression was used to assess the association between unmet need for family planning and a selection of relevant demand- and supply-side factors. Results: Of the 1309 pregnant women covered in the survey, 239 (18.26%) reported experiencing unmet need for family planning. Pregnant women with more than three living children [OR = 1.80; 95% CI (1.11–2.91)], those with a child younger than 1 year [OR = 1.75; 95% CI (1.04–2.97)], pregnant women whose partners disapproves contraceptive use [OR = 1.51; 95% CI (1.03–2.21)] and women who desired fewer children compared to their partners preferred number of children [OR = 1.907; 95% CI (1.361–2.672)] were significantly more likely to experience unmet need for family planning, while health staff training in family planning logistics management (OR = 0.46; 95% CI (0.24–0.73)] was associated with a lower probability of experiencing unmet need for family planning. Conclusion: Findings suggest the need to strengthen family planning interventions in Burkina Faso to ensure greater uptake of contraceptive use and thus reduce unmet need for family planning