A 2-D oscillating flow analysis in Stirling engine heat exchangers

A two dimensional oscillating flow analysis was conducted, simulating the gas flow inside Stirling heat exchangers. Both laminar and turbulent oscillating pipe flow were investigated numerically for Re(max) = 1920 (Va = 80), 10800 (Va = 272), 19300 (Va = 272), and 60800 (Va = 126). The results are compared with experimental results of previous investigators. Also, predictions of the flow regime on present oscillating flow conditions were checked by comparing velocity amplitudes and phase differences with those from laminar theory and quasi-steady profile. A high Reynolds number k-epsilon turbulence model was used for turbulent oscillating pipe flow. Finally, performance evaluation of the K-epsilon model was made to explore the applicability of quasi-steady turbulent models to unsteady oscillating flow analysis

Laminar/Turbulent Oscillating Flow in Circular Pipes

A two-dimensional oscillating flow analysis was conducted simulating the gas flow inside Stirling engine heat exchangers. Both laminar and turbulent oscillating pipe flow were investigated numerically for Remax = 1,920 (Va = 80), 10,800 (Va = 272), 19,300 (Va = 272), and 60,800 (Va = 126). The results are here compared with experimental results of previous investigators. Predictions of the flow regime on present oscillating flow conditions are also checked by comparing velocity amplitudes and phase difference with those from laminar theory and quasi-steady profile. A high Reynolds number k-ε turbulence model was used for turbulent oscillating pipe flow. Finally, the performance of the k-ε model was evaluated to explore the applicability of quasi-steady turbulent models to unsteady oscillating flow analysis

RADAR performance experiments

Theoretical studies and experimental results obtained at Coulommiers airport showed the capability of Proust radar to detect wind shears, in clear air condition as well as in presence of clouds or rain. Several examples are presented: in a blocking highs situation an atmospheric wave system at the Brunt-Vaisala frequency can be clearly distinguished; in a situation of clouds without rain the limit between clear air and clouds can be easily seen; and a windshear associated with a gust front in rainy conditions is shown. A comparison of 30 cm clear air radar Proust and 5 cm weather Doppler radar Ronsard will allow to select the best candidate for wind shear detection, taking into account the low sensibility to ground clutter of Ronsard radar

Characterization of Contamination Around the Largest Lead Smelter in Egypt Carried Out Through a Cooperation Program between USA and Egypt

The Government of Egypt together USAID aimed to reduce the impact of lead smelters on the environment. The major site was in Shoubra El-Kheima, where the Awadulla Secondary Lead Smelter is situated.  The Awadulla Family Company owns about 70% of the lead smelters in Egypt. This work presents the results and conclusions of a detailed on-site and off-site contaminant characterization of the Awadulla Secondary Lead Smelter.    As part of the characterization of the smelter site, soil and dust samples were collected within and near the smelter using two methods. The first consisted of collecting bulk dust and soil samples from the floor and ground in the direct vicinity of the smelter. The second involved using wet wipes to collect dust samples from walls, smooth floors, duct work, window and ledges.  The results indicate that the most contaminated soils can be found in industrial areas and on public streets in Shoubra El-Kheima. The highest lead concentrations of more than 780,000 mg.kg-1 were found inside the smelter site. Concentrations at the El-Mahy Smelter nearby reached 302,275 mg.kg-1. Residential areas had considerably lower lead levels in soil and dust.  Samples of surface water and groundwater were collected and tested for lead contamination.  Only three samples had lead concentrations above detection limits, indicating water contamination is not a problem. The maximum area affected by deposition of lead from the Awadulla smelter appears to be no more than 500 m all around the smelter. The plan calls for moving the smelters to a new industrial area called Abu Zaabal.  This move will leave behind existing structures that are highly contaminated with lead dust.  El Gobierno egipcio, junto con USAID (Agencia Estadounidense Para el Desarrollo Internacional), pretendía reducir el impacto de los hornos de fundición de plomo sobre el medio ambiente. El emplazamiento principal está en Shoubra El-Kheima, donde se encuentra el horno de fundición de plomo secundario de Awadulla. La empresa de la familia Awadulla posee aproximadamente el 70% de los hornos de fundición de plomo en Egipto. Este trabajo presenta los resultados y las conclusiones de un detallado estudio de caracterización de contaminantes en el emplazamiento y fuera del emplazamiento del horno de fundición de plomo secundario de Awadulla. Como parte de la caracterización del emplazamiento del horno de fundición, se recogieron muestras de terreno y de polvo dentro de y cerca del horno de fundición usando dos métodos. Por una parte, se recogieron muestras de polvo y de terreno a granel del suelo y la tierra en las inmediaciones directas del horno de fundición y por otra, se recogieron muestras de polvo de paredes, suelos lisos, canalizaciones, ventanas y repisas utilizando toallitas húmedas. Los resultados indican que los terrenos más contaminados se encuentran en zonas industriales y en calles públicas en Shoubra El-Kheima. Las concentraciones más elevadas, de más de 780.000 mg/kg, están dentro del emplazamiento del horno de fundición. Las concentraciones en el cercano horno de fundición de El-Mahy eran de 302.275 mg/kg. Las zonas residenciales mostraron niveles de plomo considerablemente inferiores en terreno y polvo. Se recogieron muestras de agua superficial y agua subterránea y se les realizaron pruebas para detectar contaminación por plomo. Solamente tres muestras presentaban concentraciones de plomo por encima de los límites de detección, indicando que la contaminación del agua no supone un problema. El área máxima afectada por deposición de plomo procedente del horno de fundición de Awadulla parece no ser superior a 500 metros alrededor del horno de fundición. El plan requiere trasladar los hornos de fundición a una nueva zona industrial llamada Abu Zaabal. Este traslado dejará atrás estructuras existentes que están altamente contaminadas con polvo de plomo.En collaboration avec l'USAID, le Gouvernement égyptien a élaboré un projet visant à réduire l'impact des fonderies de plomb sur l'environnement. La principale fonderie concernée était l'Awadulla Secondary Lead Smelter située à Shoubra El-Kheima. L'Awadulla Family Company détient environ 70 % des fonderies de plomb en Egypte. Cet article présente les résultats et les conclusions d'une étude de caractérisation de contaminants sur site et hors site menée sur le site de l'Awadulla Secondary Lead Smelter. Dans le cadre de cette étude, des échantillons de terre et de poussière ont été recueillis dans et à proximité de la fonderie selon deux méthodes. La première méthode a consisté à recueillir des échantillons en vrac de poussière et de terre sur le sol de la fonderie et à proximité immédiate de celle-ci. La seconde méthode a consisté à recueillir des échantillons de poussière sur les murs, les sols lisses, les conduites, les fenêtres et les rebords de celles-ci, à l'aide de chiffons humides. Les résultats ont indiqué que les sols les plus contaminés étaient localisés dans les zones industrielles et les rues de Shoubra El-Kheima. Les plus fortes concentrations, supérieures à 780 000 mg/kg, ont été relevées sur le site même de la fonderie. Des concentrations de 302 275 mg/kg ont été constatées à la fonderie voisine d'El-Mahy. Les zones résidentielles ont affiché des taux de plomb nettement plus faibles dans le sol et la poussière. Des échantillons des eaux de surface et des eaux souterraines ont été recueillis et analysés afin de déterminer la contamination au plomb. Seuls trois échantillons ont présenté des concentrations en plomb supérieures aux limites de détection, indiquant que la contamination de l'eau n'était pas inquiétante. Le périmètre touché par des dépôts de plomb de la fonderie Awadulla semble être de 500 mètres autour de la fonderie maximum. Le programme préconise le déplacement des fonderies dans une nouvelle zone industrielle dénommée Abu Zaabal. Cela implique l'abandon des structures existantes fortement contaminées par de la poussière de plomb

Targeting Trachoma Control through Risk Mapping: The Example of Southern Sudan

Trachoma, caused by the bacterium Chlamydia trachomatis, is the leading cause of preventable blindness worldwide and a major cause of blindness in Southern Sudan. However, the trachoma distribution in Southern Sudan has only been partially established and many communities in need of intervention have not been identified or targeted. Incomplete mapping and intervention coverage is largely attributable to trachoma resources being scarce and not always deployed most efficiently. The present study aimed at improving programme efficiency by developing maps to help target the available resources for trachoma surveys and interventions to areas where these are most needed. Data on active trachoma prevalence, collected during baseline surveys between 2001 and 2009, were incorporated into Bayesian geostatistical models to develop a national trachoma risk map. The model predicted the west of the country to be largely at no or very low trachoma risk, while most of the high-risk areas are located in the centre, north, and south-east. Risk mapping has allowed Southern Sudan's trachoma control programme to identify areas where collection of additional data would be most useful. As a direct result, baseline data were collected in March 2010 for the whole of Unity State, with antibiotic mass drug administration being scaled up from June 2010 onwards

SYNTHESIS AND ANTIVIRAL ACTIVITY OF NOVEL ETHYL 2-(3-HETEROCYCLE-1H-INDOL-1-YL) ACETATE DERIVATIVES

Objective: Marek's disease (MD) is a widespread, herpesvirus-induced neoplastic disease in the domestic chicken that is caused by Marek's disease virus (MDV). Marek’s disease virus (MDV) belongs to the alphaherpesvirus family such as Herpes simplex viruses 1 and 2 (HSV-1 and HSV-2). Recently Bag and co-workers 2014 reported that, 7-methoxy-1-methyl-4, 9-dihydro-3H-pyrido [3, 4-b]indole (Harmaline) showed potent anti-HSV-1 activity against both wild type and clinical isolates of HSV-1. The present work aimed to synthesize some new heterocyclic systems incorporated to indole moiety starting from ethyl 2-(3-acetyl-1H-indol-1-yl)acetate (1) in order to evaluate their antiviral activity in a trail to explore potential antiviral agents against MDV to limit the disease course and losses. Methods: Reaction of ethyl 2-(3-acetyl-1H-indol-1-yl) acetate (1) with semicarbazide hydrochloride yielded semicarbazone derivative 2. The oxidative cyclization of 2 using thionyl chloride and selenium dioxide afforded 1, 2, 3-thia and 1, 2, 3-selenadiazole derivatives 3 and 4, respectively. On the other hand, reaction of 1 with 4-chloro and 4-nitrobenzaldehydes under Claisen-Schmidt conditions gave α, β-unsaturated keto derivatives 5a, b. Cyclization of 5a, b using hydrazine hydrate, phenyl hydrazine, urea, thiourea or guanidine led to the formation of pyrazoles 6a, b, 7a, b, and pyrimidines derivatives 8a, b-10a, b; respectively. Condensation of 1 with phenyl hydrazine followed by Vilsmeier Haack formylation gave pyrazole-4-carboxaldehyde derivative 12. Reaction of aldehydic function group of 12 with different reagents led to the formation of pyrazol-5-ones 14-16, thiazolidinone 18, aziditine 19, 1, 6-diaminopyridine 21, triazolo(1, 5-a)pyridine 22 and pyrano(2, 3-c) pyrazole derivatives 23. The in vitro antiviral activity of the selected compounds 6a, b 7a, b 8a, b 9a, b and 10a, b was studied against Marek's disease virus (MDV). Results: Chicken embryo experiment showed that compounds 7b, 8b, 9b and 10a possessed significant antiviral activity with IC50 ranged between 5 and 6 µg/ml and substantial therapeutic indices (TI) of 80 and 83 were recorded. Cytotoxicity assay indicated that CC50 of 7b, 8b, 9b and 10 were greater than 400 and 500 mg/ml. Conclusion: Compounds 7b, 8b, 9b and 10a showed promising effect as anti-MDV infectivity application