Sur la rupture expérimentale des verres monolithiques pincés

Ce travail propose une étude paramétrique sur le dimensionnement des verres monolithiques pincés. Dans le cadre de cette étude, un modèle numérique a été développé afin de déterminer les contraintes de rupture dans le vitrage au voisinage des pinces. Ce modèle repose sur une campagne d'essais effectués sur des plaques de verres pincés. Le modèle prend en compte les types de produit verrier, les caractéristiques des pinces, ainsi que le comportement des intercalaires en EPDM (supposé élastique linéaire) entre les pinces et la plaque de verre. Les assemblages sont testés en flexion trois points en prenant en compte deux types de verre (trempé et recuit). Les essais de flexion sont menés jusqu'à la rupture totale de la structure verrière. La force appliquée ainsi que la flèche à la rupture sont relevées et comparées au modèle théorique. Le mode de fissuration du verre recuit est également analysé. Cette analyse met en évidence des phénomènes de rupture du verre monolithique différents selon les paramètres, par exemple la dureté de l'intercalaire. Parallèlement, un phénomène de point dur est identifié et localisé en fonction des différents paramètres précédemment identifiés. Ce phénomène est comparé à la répartition des contraintes dans le produit verrier du modèle théorique. La corrélation entre le modèle numérique et les résultats expérimentaux montre des écarts variables en fonction du type de verre et de l'épaisseur expliqués en partie, par le comportement non-linéaire de l'intercalaire

An effective organic waste recycling through vermicomposting technology for sustainable agriculture in tropics

peer reviewedPurpose The management of household wastes has been a real challenge for the capital city of Cameroon for some years now. In order to adopt ecological and sustainable strategies for better management of organic fraction of solid wastes, the present work was aimed to propose a sustainable alternative for the recycling of household organic waste through a vermicomposting process. Method A vermicomposting of household organic waste was carried out during 46 days, preceded by 23 days of pre-composting. Then, three treatments were established by mixing epigeic earthworms with different proportion of pre-composted waste. Maturation parameters such as pH, electrical conductivity (EC), C/N ratio, ammonium (N-NH4+ ) and total organic matter (TOM) were monitored about four weeks. The agronomic quality of the vermicompost was also determined at the end. Results During pre-composting, the temperature reached a maximum of 54.3±5.4°C suitable for the elimination of potential pathogen. The pH varied between 9.44 and 8.53 leading towards neutrality at the end of the vermi-composting process. The obtained mean values of C/N ratio and the TOM were respectively 11.04-11.68 and 25.82-27.19% in line with the AFNOR (NFU 44-051) guideline. The obtained vermicompost revealed high levels of nutrients such as N, P, K, Ca and Mg. The phytotoxicity test on lettuce showed germination rates above 50%, revealing the non-toxic nature of the vermicompost produced. Conclusion The vermicompost were rich in nutrients and exhibited the non-phytotoxicity. Thus, vermicomposting can be applied in the context of Cameroon to transform organic waste into organic fertiliser suitable for sustainable agriculture

Where is the ‘C’ in antenatal care and postnatal care: A multi‐country survey of availability of antenatal and postnatal care in low‐ and middle‐income settings

Objective: Antenatal (ANC) and postnatal care (PNC) are logical entry points for prevention and treatment of pregnancy‐related illness and to reduce perinatal mortality. We developed signal functions and assessed availability of the essential components of care. Design: Cross‐sectional survey. Setting: Afghanistan, Chad, Ghana, Tanzania, Togo. Sample: Three hundred and twenty‐one healthcare facilities. Methods: Fifteen essential components or signal functions of ANC and PNC were identified. Healthcare facility assessment for availability of each component, human resources, equipment, drugs and consumables required to provide each component. Main outcome measure: Availability of ANC PNC components. Results: Across all countries, healthcare providers are available (median number per facility: 8; interquartile range [IQR] 3–17) with a ratio of 3:1 for secondary versus primary care. Significantly more women attend for ANC than PNC (1668 versus 300 per facility/year). None of the healthcare facilities was able to provide all 15 essential components of ANC and PNC. The majority (>75%) could provide five components: diagnosis and management of syphilis, vaccination to prevent tetanus, BMI assessment, gestational diabetes screening, monitoring newborn growth. In Sub‐Saharan countries, interventions for malaria and HIV (including prevention of mother to child transmission [PMTCT]) were available in 11.7–86.5% of facilities. Prevention and management of TB; assessment of pre‐ or post‐term birth, fetal wellbeing, detection of multiple pregnancy, abnormal lie and presentation; screening and support for mental health and domestic abuse were provided in <25% of facilities. Conclusions: Essential components of ANC and PNC are not in place. Focused attention on content is required if perinatal mortality and maternal morbidity during and after pregnancy are to be reduced

Retard de la fécondation chez Liparis dispar

Rostand Jean. Retard de la fécondation chez Liparis dispar. In: Bulletin de la Société entomologique de France, volume 32 (15),1927. p. 225