At-Site Flood Frequency Analysis Coupled with Multiparameter Probability Distributions

The proper design of hydraulic structures as well as river basin management are directly dependent on adequate estimates of maximum streamflow, preferably obtained from long historical series. However, the scarce hydrological monitoring, recurrent in developing countries and the need for estimates associated with high return periods (RPs) have led to the use of estimation methods based statistical procedures, such as at-site flood frequency analysis. This study presents a framework for at-site flood frequency analysis coupled with multiparameter probability distribution functions (PDFs) (GEV, LN3, PE3, GLO, GPA, KAP and WAK), in which all the statistical procedures are derived from L-moments, in order to investigate the applicability of these PDFs in comparison to those of 2-parameters (EV1, LN2 and Gamma). The modeling framework was evaluated considering 106 maximum annual streamflow (MAS) series for the Rio Grande do Sul State - Brazil. PDFs’ goodness-of-fit was studied in accordance with the Anderson-Darling test. It can be concluded that: i) the multiparameter distributions, especially KAP and WAK, had performance superior to the traditional 2-parameter distributions, providing a greater number of historical series better adjusted by such multiparameter PDFs; ii) shorter series were usually better represented by GEV when compared to the other PDFs, which is an important characteristic when long historical series are not frequently available; and iii) the quantile estimates derived from multiparameter PDFs presented lower Relative Absolute Error, thus emphasizing the importance of using such PDFs in water resources management and engineering projects.     

Water Policies and Conflict Resolution of Public Participation Decision-Making Processes Using Prioritized Ordered Weighted Averaging (OWA) Operators

There is a growing interest in environmental policies about how to implement public participation engagement in the context of water resources management. This paper presents a robust methodology, based on ordered weighted averaging (OWA) operators, to conflict resolution decision-making problems under uncertain environments due to both information and stakeholders’ preferences. The methodology allows integrating heterogeneous interests of the general public and stakeholders on account of their different degree of acceptance or preference and level of influence or power regarding the measures and policies to be adopted, and also of their level of involvement (i.e., information supply, consultation and active involvement). These considerations lead to different environmental and socio-economic outcomes, and levels of stakeholders’ satisfaction. The methodology establishes a prioritization relationship over the stakeholders. The individual stakeholders’ preferences are aggregated through their associated weights, which depend on the satisfaction of the higher priority decision maker. The methodology ranks the optimal management strategies to maximize the stakeholders’ satisfaction. It has been successfully applied to a real case study, providing greater fairness, transparency, social equity and consensus among actors. Furthermore, it provides support to environmental policies, such as the EU Water Framework Directive (WFD), improving integrated water management while covering a wide range of objectives, management alternatives and stakeholders.     

A surrogate-based cooperative optimization framework for computationally expensive black-box problems

Optimization and Engineering - Most parallel surrogate-based optimization algorithms focus only on the mechanisms for generating multiple updating points in each cycle, and rather less attention...     

Fatigue and fracture analysis of a seven‐wire stainless steel strand under axial and bending loads

Fatigue failure of cables and strands is a common and complex problem. Failure is typically caused by different combinations of time‐variable bending and axial forces. In addition to these loads, contact stresses between wires may play an important role in the fatigue failure of cables. The present work aims to provide deep insight into the fatigue failure of a seven‐wire stainless steel strand subjected to a combination of variable axial and bending loads. To avoid side effects in the analysis, fatigue failure of the strand close to the clamps is prevented. Several tests were performed with a new device specifically designed to avoid failure near the clamps. Thus, failure is always produced at the middle length of the specimen. Test simulations were performed by employing the finite element method. The numerical results were validated via comparisons with experimental data. Finally, life prediction curves were obtained.     

Modeling polycrystalline materials with elongated grains

A novel algorithm to reproduce the arrangement of grains in polycrystalline materials was recently published by the authors. In this original approach, a dense package of circles (or spheres) with the same distribution as the grains is generated to produce a set of Voronoi cells that are later modified to Laguerre cells representing the original structure. This algorithm was successfully applied to materials with somewhat equidimensional grains; however, it fails for long-shaped grains. In this paper, modifications are provided in order to overcome these drawbacks. This is accomplished by moving each vertex of the Voronoi cells in such a way that the vertex should be equidistant from the particles with respect to the Euclidean distance. The algorithm is applied to packages of ellipses and spherocylinders in 2D. An example for a package of spheres is also provided to illustrate the application for a simple 3D case. The adherence between the generated packages and the corresponding tessellations is verified by means of the Jaccard coefficient (J). Several packages are generated randomly and the distribution of J coefficients is investigated. The obtained values satisfy the theoretical restraints and the quality of the proposed algorithm is statistically validated.     

Inkjet Printed Nanopatterned Aptamer‐Based Sensors for Improved Optical Detection of Foodborne Pathogens

The increasing incidence of infectious outbreaks from contaminated food and water supply continues imposing a global burden for food safety, creating a market demand for on‐site, disposable, easy‐to‐use, and cost‐efficient devices. Despite of the rapid growth of biosensors field and the generation of breakthrough technologies, more than 80% of the platforms developed at lab‐scale never will get to meet the market. This work aims to provide a cost‐efficient, reliable, and repeatable approach for the detection of foodborne pathogens in real samples. For the first time an optimized inkjet printing platform is proposed taking advantage of a carefully controlled nanopatterning of novel carboxyl‐functionalized aptameric ink on a nitrocellulose substrate for the highly efficient detection of E. coli O157:H7 (25 colony forming units (CFU) mL^?1 in pure culture and 233 CFU mL^?1 in ground beef) demonstrating the ability to control the variation within ±1 SD for at least 75% of the data collected even at very low concentrations. From the best of the knowledge this work reports the lowest limit of detection of the state of the art for paper‐based optical detection of E. coli O157:H7, with enough evidence (p > 0.05) to prove its high specificity at genus, species, strain, and serotype level.     

Influence of Oxygen on the Tribomechanical Properties of Single Crystals of YBa<Subscript>2</Subscript>Cu<Subscript>3</Subscript>O<Subscript>7−<Emphasis Type="Italic">δ</Emphasis></Subscript>

This paper reports a study on the mechanical and tribological properties of ab- and a (b) c?planes of YBa₂Cu₃O_7?δ single crystals. The single crystals were grown using a CuO-BaO self-flux method. The oxygenation effect on the mechanical and tribological properties of ab- and a (b) c?planes is reported. For the ab- plane, the hardness and elastic modulus were around 6 and 50 GPa, respectively. In this case, significant differences were not observed among the hardness and elastic modulus at different oxygenation states. However, the hardness and elastic modulus for as-grown and oxygenated YBa₂Cu₃O_7?δ single crystals were different from that of the a (b) c?plane, and were observed to be slightly higher for the as-grown than for the oxygenated samples. For as-grown and oxygenated samples, we observed hardness values around 4.7 and 2.0 GPa, respectively. Regarding the elastic modulus, the values were 75 and 40 GPa, respectively. The indentation fracture toughness values on the ab- plane for the as-grown and oxygenated YBa₂Cu₃O_7?δ single crystal were 3.7 ± 1.2 and 2.9 ± 1.2 MPa m^1/2, respectively. For the ab- plane, the scratch resistance of the as-grown sample was higher than that of the oxygenated sample and the scratches under load were deeper for the oxygenated sample. As regards the a (b) c?plane, the scar features were seemingly constant through all the scratch lengths and the scratches under load were deeper and larger for the oxygenated than that for the as-grown sample.     

Quaternary 2D Transition Metal Dichalcogenides (TMDs) with Tunable Bandgap

Alloying/doping in 2D material is important due to wide range bandgap tunability. Increasing the number of components would increase the degree of freedom which can provide more flexibility in tuning the bandgap and also reduces the growth temperature. Here, synthesis of quaternary alloys Mo_x W_1?x S_2y Se_{2(1?y )} is reported using chemical vapor deposition. The composition of alloys is tuned by changing the growth temperatures. As a result, the bandgap can be tuned which varies from 1.61 to 1.85 eV. The detailed theoretical calculation supports the experimental observation and shows a possibility of wide tunability of bandgap.