Advances in friction stir welding of steel : Project HILDA

A microstructure and property evaluation of friction stir welded DH36 6mm plate has been undertaken. The study examined a wide range of process parameters and, from this, a process parameter envelope has been developed and an initial process parameter set established that gives good welding properties. Thermo-mechanical deformation studies were developed to generate flow stress regimes over a range of stain rates and temperatures and these data will support the on-going local numerical modelling development. A preliminary thermo-fluid model has been developed to predict temperature and material flow during the FSW of steel grade DH36. In this model, materials are considered as highly viscous incompressible fluid. The welded material is flowing around the rotating tool thanks to the modelling of the friction at tool/workpiece interface. In parallel, a global numerical model is being developed to predict the inherent residual stresses and distortion of FSW butt welded assemblies often in excess of 6m long plate

Statistical Analysis of the Efficiency of an Integrated Voltage Regulator by Means of a Machine Learning Model Coupled with Kriging Regression

This paper presents a preliminary version of a probabilistic model for the uncertainty quantification of complex electronic systems resulting from the combination of the leastsquares support vector machine (LS-SVM) and the Gaussian process (GP) regression. The proposed model, trained with a limited set of training pairs provided by a set of full-wave expensive simulations, is adopted for the prediction of the efficiency of an integrated voltage regulator (IVR) with 8 uniformly distributed random parameters. The accuracy and the feasibility of the proposed model have been investigated by comparing the model predictions and its confidence intervals with the results of a Monte Carlo (MC) full-wave simulation of the device

Options for intensifying cereal-legume cropping systems in West Africa

United States Agency for International Developmen

Anemia prevalence and associated factors among schoolage children in Accra and Kumasi Metropolis in Ghana

Anemia remains a serious public health concern, globally, affecting learning ability and physical development of children. Anemic children are at a higher risk of diminished economic productivity and low earning capacity in adulthood due to impaired school performance and reduced work capacity. Anemia contributes to about a quarter of Africa’s nutrition-related Disability Adjusted Life Years. The objective of this study was to determine the prevalence of anemia and its associated risk factors among school-aged children (SAC) between ages 9 and 15 years in urban Ghana. The analysis included a randomly selected subsample of 1,634 children from a larger study on nutrition of SAC enrolled between 2009 and 2012 in private and public basic schools in the Accra and Kumasi Metropolis in Ghana. Socio-demographic and household characteristics were collected with questionnaires. Weight and height were taken to the nearest 0.1kg and 0.1cm, respectively. Dietary information was collected using a food frequency questionnaire. Data were analyzed using IBM SPSS Statistic version 23. The relationship between hemoglobin levels and socio-demographic variables, and predictors of hemoglobin levels were determined using Chi-square and binary logistic regression. The mean hemoglobin concentration of the study participants was 12.9±1.3 g/dL. In Kumasi, SAC had higher mean hemoglobin concentration (13.1±1.2 g/dL) compared to those from Accra (12.6±1.3 g/dL; p=0.001). Mean hemoglobin concentration was significantly higher among males than females (13.0±1.4 g/dL vs 12.8±1.2 g/dL; p=0.002). Prevalence of anemia was 20.4%; mild anemia was most common (13.6% of total sample). Anemia cases were higher in public schools (24.6%) compared to private (18.2%). Two-thirds of anemia cases (64.0%) were from schools in Accra. Males had significantly higher prevalence of anemia (26.5%) than females (15.9%; p <0.05). In the adjusted logistic regression model, only city of residence (OR+1.65, 95% CI: 1.44–1.83), thinness (OR=2.60, 95% CI: 1.11-5.75), stunting (OR=1.85, 95% CI: 1.99-3.10) and overweight (OR=0.60, 95% CI: 0.36-0.94) were significantly associated with anemia. In this study, anemia was significantly associated with location and nutritional status

First ampelometric study of autochthonous grapevines in Algeria: Germplasm collection of Mascara

Ampelometric studies on 26 varieties of Vitis vinifera L. belonging to the germplasm existing in the collection of Tighennif (Mascara), the most important conservatory of local grapevine varieties existing in Algeria were carried out to characterize this gene pool, the phyllometric measurement method proposed by MARTÍNEZ and GRENAN was applied to establish a cultivar specific adult leaf. Statistical analysis was performed to identify the most discriminating parameters, namely, size of angles and depth of the lateral sinuses in comparison to the lengths of the veins, especially those on the left side of the leaf. Thus, cultivars with common features such as 'Bezoul el Khadem' and 'Ahmar de Mechtras III', 'Toutrissine' and 'Aberkane' and 'Amellal' and 'Torki' were clustered together. For seven varieties the average leaf has been reconstructed.

Anemia prevalence and associated factors among school age children in Accra and Kumasi metropolis in Ghana

Anemia remains a serious public health concern, globally, affecting learning ability and physical development of children. Anemic children are at a  higher risk of diminished economic productivity and low earning capacity in adulthood due to impaired school performance and reduced work  capacity. Anemia contributes to about a quarter of Africa’s nutrition-related Disability Adjusted Life Years. The objective of this study was to  determine the prevalence of anemia and its associated risk factors among school-aged children (SAC) between ages 9 and 15 years in urban Ghana.  The analysis included a randomly selected subsample of 1,634 children from a larger study on nutrition of SAC enrolled between 2009 and 2012 in  private and public basic schools in the Accra and Kumasi Metropolis in Ghana. Socio-demographic and household characteristics were collected with  questionnaires. Weight and height were taken to the nearest 0.1kg and 0.1cm, respectively. Dietary information was collected using a food  frequency questionnaire. Data were analyzed using IBM SPSS Statistic version 23. The relationship between hemoglobin levels and socio-  demographic variables, and predictors of hemoglobin levels were determined using Chi-square and binary logistic regression. The mean  hemoglobin concentration of the study participants was 12.9±1.3 g/dL. In Kumasi, SAC had higher mean hemoglobin concentration (13.1±1.2 g/dL)  compared to those from Accra (12.6±1.3 g/dL; p=0.001). Mean hemoglobin concentration was significantly higher among males than females  (13.0±1.4 g/dL vs 12.8±1.2 g/dL; p=0.002). Prevalence of anemia was 20.4%; mild anemia was most common (13.6% of total sample). Anemia cases  were higher in public schools (24.6%) compared to private (18.2%). Two-thirds of anemia cases (64.0%) were from schools in Accra. Males had significantly higher prevalence of anemia (26.5%) than females (15.9%; p <0.05). In the adjusted logistic regression model, only city of residence (OR+1.65, 95% CI: 1.44–1.83), thinness (OR=2.60, 95% CI: 1.11-5.75), stunting (OR=1.85, 95% CI: 1.99-3.10) and overweight (OR=0.60, 95% CI: 0.36-0.94) were significantly associated with anemia. In this study, anemia was significantly associated with location and nutritional status

Chemical composition, antimicrobial, antioxidant and anticancer activities of essential oil from Ammodaucus leucotrichus Cosson & Durieu (Apiaceae) growing in South Algeria

ABSTRACT. The chemical composition of the essential oil obtained by hydrodistillation from aerial parts of A. leucotrichus Cosson & Durieu (Apiaceae) grown in the south of Algeria (El-Oued) was determined by GC-MS analysis. The oil was found to be rich in perilladehyde 64.66% and D-Limonene 26.99%. The biological activity of A. leucotrichus Cosson & Durieu essential oil has been investigated. The in vitro antimicrobial activity of the essential oil sample was tested on eight strains, one yeast and one fungi. The test showed interesting antimicrobial properties, especially on Salmonella enterica and E. coli, the antioxidant capacity of the oil was measured using the cyclic voltammetry, and the AAT value of A. leucotrichus essential oil was evaluated 47.84 mg α-TE/L. In addition, the antitumor activity showed that the oil of A. leucotrichus was very significant against the HCT116 colon cancer cell line.               KEY WORDS: Ammodaucus leucotrichus, Antioxidant activity, Anticancer activity, Cyclic voltammetry Bull. Chem. Soc. Ethiop. 2019, 33(3), 541-549. DOI: https://dx.doi.org/10.4314/bcse.v33i3.1

The Politics of Service Delivery Reform

This article identifies the leaders, the supporters and the resisters of public service reform. It adopts a principal–agent framework, comparing reality with an ‘ideal’ situation in which citizens are the principals over political policy-makers as their agents, and policy-makers are the principals over public service officials as their agents. Reform in most developing countries is complicated by an additional set of external actors — international financial institutions and donors. In practice, international agencies and core government officials usually act as the ‘principals’ in the determination of reforms. The analysis identifies the interests involved in reform, indicating how the balance between them is affected by institutional and sectoral factors. Organizational reforms, particularly in the social sectors, present greater difficulties than first generation economic policy reforms