Optimal design of water reuse networks in cities through decision support tool development and testing.

Water scarcity and droughts are an increasing issue in many parts of the world. In the context of urban water systems, the transition to circularity may imply wastewater treatment and reuse. Planning and assessment of water reuse projects require decision-makers evaluating the cost and benefits of alternative scenarios. Manual or semi-automatic approaches are still common practice for planning both drinking and reclaimed water distribution networks. This work illustrates a decision support tool that, based on open data sources and graph theory coupled to greedy optimization algorithms, is able to automatically compute the optimal reclaimed water network for a given scenario. The tool provides not only the maximum amount of served reclaimed water per unit of invested cost, but also the length and diameters of the pipes required, the location and size of storage tanks, the population served, and the construction costs, i.e., everything under the same architecture. The usefulness of the tool is illustrated in two different but complementary cities in terms of size, density, and topography. The construction cost of the optimal water reclaimed network for a city of approximately 100,000 inhabitants is estimated to be in the range of €0.17-0.22/m3 (for a payback period of 30 years).

Ultrasound in primary care: Consensus recommendations on its applications and training. Results of a 3-round Delphi study.

BACKGROUND: The introduction of portable and pocket ultrasound scanners has potentiated the use of ultrasound in primary care, whose many applications have been studied, analyzed and collected in the literature. However, its use is heterogeneous in Europe and there is a lack of guidelines on the necessary training and skills. OBJECTIVES: To identify the fundamental applications and indications of ultrasound for family physicians, the necessary knowledge and skills, and the definition of a framework of academic and pragmatic training for the development of these competencies. METHODS: A modified 3-round Delphi study was carried out in Catalonia, with the participation of 65 family physicians experts in ultrasound. The study was carried out over six months (from September 2020 to February 2021). The indications of ultrasound for family physicians were agreed (the > = 75th percentile was considered) and prioritised, as was the necessary training plan. RESULTS: The ultrasound applications in primary care were classified into seven main categories. For each application, the main indications (according to reason for consultation) in primary care were specified. A progressive training plan was developed, characterised by five levels of competence: A (principles of ultrasound and management of ultrasound scanners); B (basic normal ultrasound anatomy); C (advanced normal ultrasound anatomy); D (pathologic ultrasound, description of pathological images and diagnostic orientation); E (practical skills under conditions of routine clinical practice). CONCLUSION: Training family physicians in ultrasound may consider seven main applications and indications. The proposed training plan establishes five different levels of competencies until skill in real clinical practice is achieved.

Interface-Mediated Twinning-Induced Plasticity in a Fine Hexagonal Microstructure Generated by Additive Manufacturing.

The grain size is a determinant microstructural feature to enable the activation of deformation twinning in hexagonal close-packed (hcp) metals. Although deformation twinning is one of the most effective mechanisms for improving the strength-ductility trade-off of structural alloys, its activation is reduced with decreasing grain size. This work reports the discovery of the activation of deformation twinning in a fine-grained hcp microstructure by introducing ductile body-centered cubic (bcc) nano-layer interfaces. The fast solidification and cooling conditions of laser-based additive manufacturing are exploited to obtain a fine microstructure that, coupled with an intensified intrinsic heat treatment, permits to generate the bcc nano-layers. In situ high-energy synchrotron X-ray diffraction allows tracking the activation and evolution of mechanical twinning in real-time. The findings obtained show the potential of ductile nano-layering for the novel design of hcp damage tolerant materials with improved life spans.

Pandora's Box-Influence of Contour Parameters on Roughness and Subsurface Residual Stresses in Laser Powder Bed Fusion of Ti-6Al-4V.

The contour scan strategies in laser powder bed fusion (LPBF) of Ti-6Al-4V were studied at the coupon level. These scan strategies determined the surface qualities and subsurface residual stresses. The correlations to these properties were identified for an optimization of the LPBF processing. The surface roughness and the residual stresses in build direction were linked: combining high laser power and high scan velocities with at least two contour lines substantially reduced the surface roughness, expressed by the arithmetic mean height, from values as high as 30 µm to 13 µm, while the residual stresses rose from ~340 to about 800 MPa. At this stress level, manufactured rocket fuel injector components evidenced macroscopic cracking. A scan strategy completing the contour region at 100 W and 1050 mm/s is recommended as a compromise between residual stresses (625 MPa) and surface quality (14.2 µm). The LPBF builds were monitored with an in-line twin-photodiode-based melt pool monitoring (MPM) system, which revealed a correlation between the intensity quotient I2/I1, the surface roughness, and the residual stresses. Thus, this MPM system can provide a predictive estimate of the surface quality of the samples and resulting residual stresses in the material generated during LPBF.

Peritectic titanium alloys for 3D printing.

Metal-based additive manufacturing (AM) permits layer-by-layer fabrication of near net-shaped metallic components with complex geometries not achievable using the design constraints of traditional manufacturing. Production savings of titanium-based components by AM are estimated up to 50% owing to the current exorbitant loss of material during machining. Nowadays, most of the titanium alloys for AM are based on conventional compositions still tailored to conventional manufacturing not considering the directional thermal gradient that provokes epitaxial growth during AM. This results in severely textured microstructures associated with anisotropic structural properties usually remaining upon post-AM processing. The present investigations reveal a promising solidification and cooling path for α formation not yet exploited, in which α does not inherit the usual crystallographic orientation relationship with the parent ß phase. The associated decrease in anisotropy, accompanied by the formation of equiaxed microstructures represents a step forward toward a next generation of titanium alloys for AM.

Inducing Stable α + ß Microstructures during Selective Laser Melting of Ti-6Al-4V Using Intensified Intrinsic Heat Treatments.

Selective laser melting is a promising powder-bed-based additive manufacturing technique for titanium alloys: near net-shaped metallic components can be produced with high resource-efficiency and cost savings [...].

Non-negative matrix factorization for the near real-time interpretation of absorption effects in elemental distribution images acquired by X-ray fluorescence imaging.

Elemental distribution images acquired by imaging X-ray fluorescence analysis can contain high degrees of redundancy and weakly discernible correlations. In this article near real-time non-negative matrix factorization (NMF) is described for the analysis of a number of data sets acquired from samples of a bi-modal α+ß Ti-6Al-6V-2Sn alloy. NMF was used for the first time to reveal absorption artefacts in the elemental distribution images of the samples, where two phases of the alloy, namely α and ß, were in superposition. The findings and interpretation of the NMF results were confirmed by Monte Carlo simulation of the layered alloy system. Furthermore, it is shown how the simultaneous factorization of several stacks of elemental distribution images provides uniform basis vectors and consequently simplifies the interpretation of the representation.

Collaborative intervention to improve airway assessment and safety in management for anaesthesia: the Qualitat & Via Aèria (QUAVA) study.

BACKGROUND: Airway assessment and management are cornerstones of anaesthesia, yet airway complications remain an important source of morbidity. OBJECTIVE: We performed a before-and-after evaluation of a collaborative intervention to improve adherence to airway assessment and management guidelines in patients scheduled for surgery under general anaesthesia. DESIGN: A prospective, multicentre before-and-after evaluation of a collaborative intervention. SETTING: Collaborative intervention to improve adherence to airway assessment and management guidelines in patients scheduled for surgery under general anaesthesia. Data were collected on 21 consecutive days before and after the intervention. PARTICIPANTS: Anaesthetists with staff or residency positions at 22 hospitals. Patients aged 18 years or older undergoing nonemergency surgery were recruited. INTERVENTION: Establishing a learning network that included local leaders, meetings to share experiences and knowledge, interactive sessions and provision of printed materials on airway assessment and management. Clinical airway management for general anaesthesia was provided by the anaesthetists participating in the study. MAIN OUTCOME MEASURES: Outcomes were the completion of airway assessment at the preanaesthetic visit, rates of unanticipated difficult airway, algorithm adherence and related airway complications. RESULTS: The study included 3753 patients (1947 preintervention and 1806 postintervention). The percentage of patients with a complete airway assessment increased from 25.1% preintervention to 48.4% postintervention (P <0.001). The incidences of unanticipated difficult airway were 4.1% before the intervention and 3% after it (P = 0.433). Rates of adherence to the algorithms for anticipated and unanticipated difficult airway management were similar in the two periods. The incidences of related adverse events were also similar. CONCLUSION: The collaborative intervention was effective in improving airway assessment but not in changing difficult airway management practices.

Lightwand tracheal intubation with and without muscle relaxation.

BACKGROUND: Lightwand tracheal intubation is a suitable technique for patients who are difficult to intubate but who are receiving effective ventilation. The effect of muscle relaxants on the efficacy of lightwand intubation has not yet been evaluated. The authors conducted a prospective, double-blind, placebo-controlled study to assess the effectiveness and incidence of complications of lightwand tracheal intubation performed during general anesthesia with and without the use of a muscle relaxant in patients with apparently normal airway anatomy. METHODS: One hundred seventy-six patients who required orotracheal intubation were prospectively included. Anesthesia was administered using propofol (2 mg/kg, then 3 mg . kg (-1). h(-1)) and remifentanil (1 microg/kg, then 0.3 microg . kg(-1) . min(-1)). Patients were randomly assigned to one of two groups (n = 88 for each) to receive rocuronium 0.6 mg/kg or saline intravenously. Lightwand orotracheal intubation (Trachlight; Laerdal Medical Inc., Armonk, NY) was attempted after 3 min. The authors recorded the number of successful intubations, the number of attempts and their duration, and events during the procedure. RESULTS: The failure rate of lightwand intubation was 12% in the placebo group and 2% in the rocuronium group (P = 0.021). Patients in the placebo group received more multiple intubation attempts (P < 0.001), required a greater intubation time (77 +/- 65 vs. 52 +/- 31 s; P = 0.002) and experienced a greater incidence of events during intubation (61 vs. 0%; P < 0.001) than patients in the rocuronium group. CONCLUSIONS: The use of muscle relaxants in patients with apparently normal airways is associated with a lower failure rate, decreased intubation time, and fewer attempts when performing lightwand orotracheal intubation.