Acoustic emission behavior of steel fibre reinforced concrete under bending

The present paper describes the acoustic emission (AE) behavior of concrete under four-point bending. Steel fibres of varying content were used as reinforcement in concrete slabs and their influence on the fracture process and the acoustic activity was investigated. The total acoustic emission (AE) activity was found to be directly proportional to the fibre content. Analysis revealed that particular AE parameters change monotonically with the progress of damage and can be used for the characterization of the failure process

Effect of defoliation on leaf physiology of sugar beet cultivars subjected to water stress and re-watering

Abstract Water stress causes defoliation, which can reduce yield and root quality of sugar beets (Beta vulgaris L.) through altered gas exchange characteristics of the leaves. In a two-year experiment, three sugar beet cultivars (Europa, Rival and Corsica) were subjected to three defoliation levels (control-C, moderate-MD, severe-SD) and re-watering after their exposition to drought for a month. Leaf physiological traits including net photosynthesis (A), transpiration rate (E), stomatal conductance (g s ), intracellular CO 2 (C i ), water use efficiency (WUE L -A/E and WUE i -A/g s ), leaf N concentration, petiole NO 3 -N concentration, specific leaf area (SLA), leaf water potential (WP) and leaf water content (LWC), were determined before defoliation and 15, 30 and 40 days after defoliation (DAD). On contrary to previous reports, water-stressed cultivars differed significantly in their leaf physiology; the late-season cultivar Corsica had the lowest E and g s values without any significant reduction in A. Thus, Corsica was the most water-conservative cultivar. Re-watering rapidly restored leaf physiology but a gradual decline, with the progress of DAD, was evident for A, E, g s and C i . After re-growth, cultivars differed only in WP and LWC with Europa, the early-harvested cultivar, to have the highest values. Thus, the better response (higher yield increase and lower root quality degradation) of Corsica to re-watering and the subsequent re-growth, as reported b

Acoustic emission behavior of steel fibre reinforced concrete under bending

a b s t r a c t The present paper describes the acoustic emission (AE) behavior of concrete under four-point bending. Steel fibres of varying content were used as reinforcement in concrete slabs and their influence on the fracture process and the acoustic activity was investigated. The total acoustic emission (AE) activity was found to be directly proportional to the fibre content. Analysis revealed that particular AE parameters change monotonically with the progress of damage and can be used for the characterization of the failure process

Evaluation of a quality improvement intervention to reduce anastomotic leak following right colectomy (EAGLE): pragmatic, batched stepped-wedge, cluster-randomized trial in 64 countries

Background: Anastomotic leak affects 8 per cent of patients after right colectomy with a 10-fold increased risk of postoperative death. The EAGLE study aimed to develop and test whether an international, standardized quality improvement intervention could reduce anastomotic leaks. Methods: The internationally intended protocol, iteratively co-developed by a multistage Delphi process, comprised an online educational module introducing risk stratification, an intraoperative checklist, and harmonized surgical techniques. Clusters (hospital teams) were randomized to one of three arms with varied sequences of intervention/data collection by a derived stepped-wedge batch design (at least 18 hospital teams per batch). Patients were blinded to the study allocation. Low- and middle-income country enrolment was encouraged. The primary outcome (assessed by intention to treat) was anastomotic leak rate, and subgroup analyses by module completion (at least 80 per cent of surgeons, high engagement; less than 50 per cent, low engagement) were preplanned. Results: A total 355 hospital teams registered, with 332 from 64 countries (39.2 per cent low and middle income) included in the final analysis. The online modules were completed by half of the surgeons (2143 of 4411). The primary analysis included 3039 of the 3268 patients recruited (206 patients had no anastomosis and 23 were lost to follow-up), with anastomotic leaks arising before and after the intervention in 10.1 and 9.6 per cent respectively (adjusted OR 0.87, 95 per cent c.i. 0.59 to 1.30; P = 0.498). The proportion of surgeons completing the educational modules was an influence: the leak rate decreased from 12.2 per cent (61 of 500) before intervention to 5.1 per cent (24 of 473) after intervention in high-engagement centres (adjusted OR 0.36, 0.20 to 0.64; P < 0.001), but this was not observed in low-engagement hospitals (8.3 per cent (59 of 714) and 13.8 per cent (61 of 443) respectively; adjusted OR 2.09, 1.31 to 3.31). Conclusion: Completion of globally available digital training by engaged teams can alter anastomotic leak rates. Registration number: NCT04270721 (http://www.clinicaltrials.gov)

Genotypic response to re-growth of defoliated sugar beets after re-watering in a water-limited environment: effects on yield and quality.

Abstract Defoliation produced by abiotic factors and the subsequent re-growth can reduce sugar beet (Beta vulgaris L.) sucrose content and final sugar yield. Field experiments were conducted during 2003 and 2004 growing seasons in the farm of Hellenic Sugar Industry SA, Larissa factory, central Greece. Three sugar beet cultivars (Rival, Europa and Corsica) were ordinary irrigated till the beginning of July and then left without irrigation for a month. Three defoliation levels (control-C, moderate-MD and severe-SD) were performed at early August and irrigation was simultaneously started to promote re-growth. Four samplings were conducted (before defoliation, 15, 30 and 40 days after defoliation) to determine the changes in physiological and productive traits. Yields were lower in 2003 compared to 2004 because sugar beets were grown under more stressful conditions due to the delayed sowing, the higher temperatures and the lower rainfall. Both defoliation level and cultivar had significant effects on physiological and productive traits after re-growth only in 2003. The late-season cultivar, Corsica, showed better LAI maintenance compared to Europa and Corsica and had the greatest performance after re-growth in regard to fresh root weight and sugar yield. Also, this cultivar showed the least decrease of sucrose percentage in fresh root weight and juice purity mainly due to the stable potassium (K) concentration and limited increase of sodium (Na) accumulation in roots. Corsica consumed the least root α-amino N for its re-growth. Quantitative and qualitative traits were negatively affected only by the SD treatment. Plants suffered from MD treatment gradually recovered during growing season. This study demonstrates that under Mediterranean conditions, the adverse effects of re-growth on sugar beet yield and quality depend on the growing conditions and they can be restricted by the selection of an appropriate cultivar

Effects of Fibre Geometry and Volume Fraction on the Flexural Behaviour of Steel-Fibre Reinforced Concrete

This work aims in studying the mechanical behaviour of concrete, reinforced with steel fibres of different geometry and volume fraction. Experiments include compression tests and four-point bending tests. Slump and air content tests were performed on fresh concrete. The flexural toughness, flexural strength and residual strength factors of the beam specimens were evaluated in accordance with ASTM C1609/C1609M-05 standard. Improvement in the mechanical properties, in particular the toughness, was observed with the increase of the volume fraction of steel-fibres in the concrete. The fibre geometry was found to be a key factor affecting the mechanical performance of the material.Strai