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Shear resistance by beams without stirrups presents the transfer of shear and normal principal stresses across the open cracks within reinforced concrete (RC) beams. The complexity of the shear mechanism is further complicated by the distorted structure of RCA, which is composed of hardened adhered surface mortar and virgin aggregate. Compression field theory (CFT) postulates a series of curves for shear-loaded beams to signify the transfer of tensile and compressive stresses in concrete beams across developed shear cracks. Special attention is given to beams with recycled materials, which do not necessarily give the same strength as virgin aggregate. A numerical shear model is developed that accounted for the fracture characteristics, modes I and II of the beam containing RCA along the primary crack path from dowel action, aggregate interlock, and uncracked compression zone of the beam. The model captures the correlation of shear arm ratio, longitudinal reinforcement ratio, maximum coarse aggregate size, and concrete strength. The study model was validated using experimental results from 139 concrete beams containing RCA without stirrups. The strength ratio resulted in mean of 1.32 with a standard deviation of 0.48, a coefficient of variation of 36.8% and R-squared value of 0.65. The statistical evaluations of the model were compared with the other nine (9) theoretical models by authors and codes of practice. The developed model predicted a relatively higher shear strength value due to the inclusion of contribution from dowel action, aggregate interlock and compression zone.

Chronic distal thoracic dissections treated with thoracic endovascular repair are prone to type Ib false lumen perfusion. When the supraceliac aorta is of normal caliber, fenestration of the dissection flap proximal to the visceral vessels creates a seal zone for the thoracic stent graft and eliminates the type Ib false lumen perfusion. We describe a novel way of crossing the septum using electrocautery delivered through a wire tip then fenestrating the septum using electrocautery delivered over a 1-mm area of uninsulated wire to cut the septum. We believe the use of electrocautery creates a controlled and deliberate aortic fenestration during endovascular repair of a distal thoracic dissections.

Improving geo-information decision evaluation is an important part of geospatial decision support research, particularly when considering vulnerability, risk, resilience, and sustainability (V-R-R-S) of urban land–water systems (ULWSs). Previous research enumerated a collection of V-R-R-S conceptual component commonalties and differences resulting in a synthesis concept called VRRSability. As a single concept, VRRSability enhances our understanding of the relationships within and among V-R-R-S. This paper reports research that extends and deepens the VRRSability synthesis by elucidating relationships among the V-R-R-S concepts, and organizes them into a VRRSability conceptual framework meant to guide operationalization within decision support systems. The core relationship within the VRRSability framework is ‘functional performance’, which couples land and water concerns within complex ULWS. Using functional performance, we elucidate other significant conceptual relationships, e.g., scale, scenarios and social knowledge, among others. A narrative about the functional performance of green stormwater infrastructure as part of a ULWS offers a practical application of the conceptual framework. VRRSability decision evaluation trade-offs among land and water emerge through the narrative, particularly how land cover influences water flow, which in turn influences water quality. The discussion includes trade-offs along risk–resilience and vulnerability–sustainability dimensions as key aspects of functional performance. Conclusions include knowledge contributions about a VRRSability conceptual framework and the next steps for operationalization within decision support systems using artificial intelligence.

Coconut shell concrete beams containing coconut shell ash are a feasible alternative to traditional reinforced concrete beams in structural applications. Coconut shells in reinforced concrete beams are essential in earthquake-prone areas because of their ductility properties, which contribute to enhancing earthquake resistance. This research investigates the flexure, ductility, shear, and cracking behavior of reinforced concrete beams made from the incorporation of a minimum quantity of untreated coconut shell particles (CSP) at 5% substitution of coarse aggregate (CA) modified with coconut shell ash (CSA) at 10% substitution of Ordinary Portland cement (OPC). Two beams were evaluated for flexural, strain, ductility, and cracking behavior. In contrast, the other two were evaluated for flexural, shear, strain, ductility, and cracking behavior by repositioning the loading point to the distance of 200 mm close to the support. In comparison to control beams evaluated for flexural, shear, strain, ductility, and cracking behavior, the ductility ratio of concrete beams with 10% CSA and 5% CSP improved by 8.8%. The ductile improvement was observed with a 17.3% decrease in flexural load. The shear capacity of reinforced concrete beams with 10% CSA and 5% CSP improved compared to the reference literature in the study. Finally, it was discovered that combining 10% CSA and 5% CSP in reinforced concrete beams can improve ductility without significantly reducing ultimate failure load.

Measurement(s) Preventive Intervention • Public Health Technology Type(s) natural language processing objective • Artificial Intelligence Sample Characteristic - Environment anthropogenic environment Sample Characteristic - Location Global Machine-accessible metadata file describing the reported data: https://doi.org/10.6084/m9.figshare.13999484

The demand for virgin aggregates for concrete production worldwide has been increasing. At the same time, there is an increase in the production of rubbles from construction-related activities. The residues are produced either due to leftovers or from the demolished structures. However, worldwide, the utilization of recycled concrete aggregate (RCA) material for structural concrete has been limited, often considered inferior due to distorted surfaces. The problems with RCA arise because it is a composite aggregate made of natural aggregate and cement, and adhered surface mortar is the discontinuities on the surface that arise from the production technique or the strength of the original concrete. The development of hydrated calcium silicate binder in the concrete matrix has been the critical desire of researchers to make better concrete material. This research focuses on the treatment of RCA from locally available rice husk ash with minimum pozzolanic cement. The objective was achieved by conducting tests on the properties of aggregates that include specific gravity and water absorption, aggregate crushing value (ACV), and aggregate impact value (AIV). The effectiveness of the treatment technique is assessed by the analysis of SEM imagery and XRD analysis of the microstructure cement paste around the RCA. At 20% pozzolan concentration, RCA treatment yields comparable specific gravities, water absorption, ACV, and AIV. Furthermore, the replacement of 5% rice husk ash (in 20% concentration) provided the optimal proportion of treatment for RCA, resulting in a reduction of ACV by 31.4%, AIV by 30.0%, and water absorption by 12.7% compared to the untreated RCA. XRD showed that calcite (CaCO₃), quartz, and portlandite phases were the majority in the untreated RCA. The study indicates that pozzolanic cement with 15% can be used with 5% RHA to produce RCA with characteristics almost similar to virgin aggregates. This research presents a consistent methodology to achieve modified RCA for application in construction.

The use of concrete mixes with recycled materials has gained traction in research communities. However, the major drawback of the recycled concrete aggregate (RCA) has been the contribution of the cement paste mortar attached to the surface. The quantity of surface-attached mortar on the virgin aggregate dominates and defines the shear performance of concrete beams. Concrete shear failure is usually abrupt and catastrophic, especially in concrete beams without shear reinforcement. The effectiveness of the maximum size of RCA for the performance of untreated and treated with pozzolanic cement and rice husk ash (RHA) slurry was investigated. A total of sixteen (16) beams containing RCA of four (4) maximum sizes, 10, 14, 20, and 25 mm, were prepared and tested after 28 days. The beams were loaded in shear using shear span-depth ratios of 1.25 and 2.50. The results showed that the shear strength of the beams increases as the aggregate size increases to a maximum size of 20 mm, beyond which the shear strength reduces. It was attributed to the attached mortar, which increased as the size of the aggregate increased, creating a weak zone for shear failure in the concrete. In addition, RCA pretreatment using slurry-containing cement and RHA strengthened the attached mortar on the aggregate surface. It resulted in a dense and more compact aggregate that slightly improved the shear strength by about 2.2% for beams containing 20 mm RCA size. The ultimate shear strength of the experimental work in the study was predicted using eight (8) selected models from the literature. Models that account for the aggregate size and shear span to depth ratio resulted in shear strength ratios of 1.29, 0.91, 1.08, and 1.20 for Bažant and Becq-Giraudon, 2002, Zsutty, 1968, Xu et al., 2012, and Gastebled and May, 2001, which are almost similar outcomes to the experimental results.

The behavior of concrete-filled uPVC tubular columns under axial compression loads were studied experimentally by testing columns prepared from five different concrete strength classes. Accordingly, the unconfined, concrete-filled uPVC tube with and without wire-mesh reinforced mortar cover and reinforced concrete columns were evaluated. The main variables considered in this study are concrete strength$$ ({f_{co}})$$, uPVC thickness to diameter ratio (2t/D) and aspect ratio (h/D). The effect of uPVC confinement on strength, ductility, energy absorption, and post-peak behavior was explored. Also, a model was developed to predict the peak strength. Results show that the uPVC confinement increased the strength, ductility, and energy absorption in between 1.28–2.35, 1.84–15.3, and 11–243 times the unconfined, respectively. The confinement performed well on increasing the strength, ductility, and energy absorption for lower concrete strength and higher 2t/D ratios. The post-peak behavior of the stress-strain curve was affected by 2t/D and h/D ratios; an abrupt drop in the stress-strain curve was observed in specimens with lower 2t/D and higher h/D ratio. For a given value of concrete strength $$({f_{co}})$$, tensile strength$$ \left({{f_y}} \right)$$, thickness (t), diameter (D), and height (h), the stress-strain model predicted the peak strength of axially loaded concrete-filled uPVC tube column with a mean absolute error of 2.7%.

This paper synthesizes vulnerability, risk, resilience, and sustainability (VRRS) in a way that can be used for decision evaluations about sustainable systems, whether such systems are called coupled natural–human systems, social–ecological systems, coupled human–environment systems, and/or hazards influencing global environmental change, all considered geospatial open systems. Evaluations of V-R-R-S as separate concepts for complex decision problems are important, but more insightful when synthesized for improving integrated decision priorities based on trade-offs of V-R-R-S objectives. A synthesis concept, called VRRSability, provides an overarching perspective that elucidates Tier 2 of a previously developed four-tier framework for organizing measurement-informed ontology and epistemology for sustainability information representation (MOESIR). The new synthesis deepens the MOESIR framework to address VRRSability information representation and clarifies the Tier 2 layer of abstraction. This VRRSability synthesis, composed of 13 components (several with sub-components), offers a controlled vocabulary as the basis of a conceptual framework for organizing workflow assessment and intervention strategies as part of geoinformation decision support software. Researchers, practitioners, and machine learning algorithms can use the vocabulary results for characterizing functional performance relationships between elements of geospatial open systems and the computing technology systems used for evaluating them within a context of complex sustainable systems.

This special issue of the ISPRS International Journal of Geographic Information about “Coastal GIS” is motivated by many circumstances. More than one-half of the world’s human population lives in coastal areas (within 200 kilometers of coast) as of 2000 [1]. The trend toward coastal habitation is expected to continue in the US with the total being 75 percent by 2025, meaning that coastal human–environment interactions will likely increase and intensify [2]. Geographic information systems (GIS) are being developed and used by technical specialists, stakeholder publics, and executive/policy decision makers for improving our understanding and management of coastal areas, separately and together as more organizations focus on improving the sustainability and resilience of coastal systems. Coastal systems—defined as the area of land closely connected to the sea, including barrier islands, wetlands, mudflats, beaches, estuaries, cities, towns, recreational areas, and maritime facilities, the continental seas and shelves, and the overlying atmosphere—are subject to complex and dynamic interactions among natural and human-driven processes. Coastal systems are crucial to regional and national economies, hosting valued human-built infrastructure and providing ecosystem services that sustain human well-being. This special issue of IJGI about coastal GIS presents a collection of nine papers that address many of the issues mentioned above. [...]

There is always a need for more durable, ductile, and robust materials for buildings, bridges, and other infrastructure due to the drawbacks of existing construction materials. Some of the drawbacks are the corrosion of steel, the brittle failure of concrete, and the performance instabilities that are caused when exposed to different environments. Thus, an innovative system is required to improve the performance and retain the integrity of structures in a harsh environment. To alleviate the situation, Un-plasticized polyvinyl chloride (uPVC) tubes are used as a confining material and their performance was experimentally evaluated by testing uPVC confined equivalent cylinders. Accordingly, unconfined and uPVC confined equivalent concrete cylinders for five different concrete classes, four types of uPVC tube sizes, and the aspect ratios of two (h/D = 2) were prepared and tested under axial compression loads. The result shows that the uPVC confinement increased the strength, ductility factor, and energy absorption in between 1.28–2.35, 1.84–15.3, and 11–243 times the unconfined levels, respectively. The confinement performed well for lower concrete classes and higher thickness to diameter ratios (2t/D). The post-peak behavior of the stress-strain curve was affected by the 2t/D ratio and the absolute value of the slope decreased as the 2t/D ratio increased. Additionally, the uPVC tube has shown several advantages, such as acting as a permanent formwork, protecting the concrete from chemical attacks, preventing the segregation of concrete, preventing peeling, and taking off concrete cover, decreasing the cross-section, and resulting in lighter sections. The uPVC confinement provided a remarkable improvement on the strength, ductility, energy absorption, and post-peak behavior of concrete. Therefore, uPVC tubes can be used as confining material for bridge piers, piles, electric poles, and highway signboards, where the fire risk is very small, though additional research is required on fire resistance mechanisms, such as wire-mesh reinforced mortar cover.

Introduction: The effects of chronic kidney disease (CKD) on outcomes in patients undergoing semi-urgent and elective percutaneous coronary intervention (PCI) are unclear. This study aims to investigate impact of CKD on long-term outcomes of this population., Methods: This was a retrospective cohort study of patients who underwent semi-urgent and elective PCI from 1 January 2014 to 31 December 2015 at a tertiary academic center. They were stratified into five groups - group 1 [estimated glomerular filtration rate (eGFR) ≥90 ml/min/1.73m2], group 2 (eGFR 60-89 ml/min/1.73m2), group 3 (eGFR 30-59 ml/min/1.73 m2), group 4 (eGFR <30 ml/min/1.73m2), and group 5 (dialysis). Demographics, risk factors in relation to endpoints of all-cause mortality, contrast-induced nephropathy (CIN), three-point major adverse cardiac events (MACE) (cardiac death, subsequent myocardial infarction, subsequent stroke), and four-point MACE (including target lesion revascularization) were analyzed., Results: One thousand six hundred nine patients were included. Advanced CKD patients were more likely to be female and older, with higher prevalence of co-morbidities. Compared to group 1, group 4 patients were associated with increased risk of three-point [adjusted hazard ratio (aHR) 1.94, 95% confidence interval (CI): 1.06-3.55; P = 0.031] and four-point MACE (aHR 2.15, 95% CI: 1.21-3.80; P = 0.009). However, higher contrast volume usage [odds ratio (OR) 2.20, 95% CI: 1.04-4.68; P = 0.040) was associated with increased CIN risk but not reduced eGFR (OR 1.62, 95% CI: 0.57-4.65; P = 0.369)., Conclusion: Advanced CKD patients undergoing PCI were associated with higher co-morbid burden. Despite adjustments for co-morbidities, these patients had higher mortality and worse cardiovascular outcomes at 3 years following contemporary PCI., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)