8 research outputs found

    Experimental performance investigations on various orientations of evacuated double absorber tube for solar parabolic trough concentrator

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    The parabolic trough concentrator is a widely used concentrator to harness and concentrate on the solar energy. The performance of the parabolic trough concentrator depends upon its various parameters like reflecting surface, mass flow rate, concentration ratio, heat transfer fluid, rim angle, tracking of system, evacuation of absorber, and absorber tube. An absorber tube or receiver is the most important parameter that has an effect on the enhancement of heat transfer which was further specified by its material, surface coating, length, diameter, type of flow through it, number of absorber tube, various orientations of double tube, internal flow obstructions like twisted tape, different shape insertion in it etc. Different researchers had worked on different modifications of the absorber tube to increase the effective heat transfer. In this present experimental work, an investigation of the evacuated double tube absorber with its various orientations carried out for the designed and developed prototype of PTC.Scopu

    Visual Field Defects in Deformational Posterior Plagiocephaly

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    Purpose: We sought to determine whether visual field abnormalities occur in infants with deformational posterior plagiocephaly and to assess whether there is a relationship between the severity and laterality of visual field abnormalities with the severity and laterality of skull deformity. Methods: A retrospective chart review was performed on 40 consecutive infants with deformational posterior plagiocephaly. Each was tested with standardized binocular arc perimetry in the horizontal plane. Sixteen patients also had 3-dimensional computed tomography of the skull. Hemifield asymmetry of ≥20 degrees and/or a decrease in hemifield values by ≥20 degrees from established normal patients was considered abnormal. Visual field data from study patients was plotted against previously published normative data. Graphs comparing visual field defects and laterality to cranial asymmetry also were generated. Results: Thirty-five percent of infants with deformational posterior plagiocephaly had constriction of one or both hemifields by at least 20 degrees from established normal patients. Hemifield asymmetry of 20 degrees or more was found in 17.5% of infants tested. There was a significant difference in the worse hemifield values measured in each patient and the standard visual fields obtained from normative data ( P = 0.036). There was no correlation between the laterality of the visual fields to the laterality of the defects. A correlation between severity of hemifield constriction and % asymmetry on computed tomography was noted ( P = 0.209). Conclusions: Deformational posterior plagiocephaly may affect visual field development but neither the laterality nor the severity of skull deformity is predictive of the severity of visual field defects

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

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    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)
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