GaSbBi alloys and heterostructures: fabrication and properties

International audienceDilute bismuth (Bi) III-V alloys have recently attracted great attention, due to their properties of band-gap reduction and spin-orbit splitting. The incorporation of Bi into antimonide based III-V semiconductors is very attractive for the development of new optoelectronic devices working in the mid-infrared range (2-5 µm). However, due to its large size, Bi does not readily incorporate into III-V alloys and the epitaxy of III-V dilute bismides is thus very challenging. This book chapter presents the most recent developments in the epitaxy and characterization of GaSbBi alloys and heterostructures

EPIdemiology of Surgery-Associated Acute Kidney Injury (EPIS-AKI) : Study protocol for a multicentre, observational trial

More than 300 million surgical procedures are performed each year. Acute kidney injury (AKI) is a common complication after major surgery and is associated with adverse short-term and long-term outcomes. However, there is a large variation in the incidence of reported AKI rates. The establishment of an accurate epidemiology of surgery-associated AKI is important for healthcare policy, quality initiatives, clinical trials, as well as for improving guidelines. The objective of the Epidemiology of Surgery-associated Acute Kidney Injury (EPIS-AKI) trial is to prospectively evaluate the epidemiology of AKI after major surgery using the latest Kidney Disease: Improving Global Outcomes (KDIGO) consensus definition of AKI. EPIS-AKI is an international prospective, observational, multicentre cohort study including 10 000 patients undergoing major surgery who are subsequently admitted to the ICU or a similar high dependency unit. The primary endpoint is the incidence of AKI within 72 hours after surgery according to the KDIGO criteria. Secondary endpoints include use of renal replacement therapy (RRT), mortality during ICU and hospital stay, length of ICU and hospital stay and major adverse kidney events (combined endpoint consisting of persistent renal dysfunction, RRT and mortality) at day 90. Further, we will evaluate preoperative and intraoperative risk factors affecting the incidence of postoperative AKI. In an add-on analysis, we will assess urinary biomarkers for early detection of AKI. EPIS-AKI has been approved by the leading Ethics Committee of the Medical Council North Rhine-Westphalia, of the Westphalian Wilhelms-University Münster and the corresponding Ethics Committee at each participating site. Results will be disseminated widely and published in peer-reviewed journals, presented at conferences and used to design further AKI-related trials. Trial registration number NCT04165369

Study of the effect of the nature of aggregates on the mechanical behaviour of the concrete in hot and dry zones «Contribution of the curing»

Laghouat est parmi les villes de l’Algérie riches en matériaux de différentes natures, tels que les roches calcaires massives et les matériaux alluvionnaires meubles siliceux et silico-calcaires. L’objectif premier de ce travail est d’établir une comparaison des performances mécaniques des bétons préparés avec de granulats de natures différentes. Nôtre second objectif est l’étude de l’influence de la cure sur la résistance à la compression et la résistance à la flexion des bétons étudiés. Les échantillons sont conservés sous un climat chaud et sec réel qui est le climat de Laghouat. Nous avons utilisé comme cure: le film plastique, la toile de jute mouillée et l’immersion dans l’eau. A travers ce travail expérimental, nous avons pu constater que les meilleures résistances à la compression sont obtenues dans les bétons à sable siliceux et celles à la flexion sont obtenues dans les bétons à granulats calcaires. La conservation du béton dans une ambiance aride sans protection augmente sa résistance mécanique à jeune âge, mais à long terme, cette dernière chute d’une façon significative. L’étude a mis en évidence la nécessité de l’emploi d’un super plastifiant et de l’application immédiate de la cure pour le bétonnage en climat chaud

Modeling of dimensional variations of a dune sand concrete reinforced by addition of steel fibers

International audienc

EVALUATION OF CEMENT THIXOTROPY FOR THE CEMENT OF OIL WELLS IN AREAS WITH LOSSES: EFFECT OF PLASTER AND DAIRY OF HIGH FURNACES

Cementing of oil and gas wells can be a very delicate operation. Among the concerns of service companies, during this operation are the nature and conditions of the formations in well. This is the case of cementing operations in southern Algeria, specifically on the fields of In-Amen, where the formations in lost zones are naturally weak and highly permeable. In these areas, drilling fluids (muds and cements) pumped will be, completely or partially lost, what we call "lost circulation". Thixotropic cements are useful to overcome lost circulation problems. They are characterized by a special rheological behavior, allowing it to plug lost zones when they are pumped. Our work aims to assess the thixotropy of cements perapred with two types of cement (class G Asland cement and CEM I 42.5 portland cement) with the plaster, using a viscometer with coaxial cylinder (couette type). Moreover, the effect of blast furnace slag (LHF) on the properties and thixotropic mixtures prepared was also studied. The results show that portland cement (available locally) can produce mixes with higher and more stable thixotropy than the class G cement (from importation), which is a practical and economical for cementing job operations in wells with loss zones. The results also show that the effect of LHF is positive, since in addition to his contribution to long term performances, especially the durability of hardened concrete, it improves the thixotropy of cement made of plaster