Lessons from the Seismic Performance of Pile-Supported Bridges Affected by Liquefaction During the M8.8 2010 Maule Chile Earthquake

Ground failure case studies have been the source of the most important advances in geotechnical earthquake engineering over the past 50 years. Documented case histories from the 2010 M8.8 Maule Chile earthquake will, if carefully studied, further advance this field. The 2010 M8.8 earthquake in Chile showed that liquefaction-induced soil-foundation-structure interaction problems are still far from being completely understood. The observed damage and partial collapse of pile-supported bridges like Juan Pablo II, Llacolén, Tubul, La Mochita, and Raqui, is most likely due to the effects of liquefaction-induced lateral and vertical ground displacement, which often causes large ground deformations that impose kinematic loads on the pile foundations. In this paper, simplified back-analyses regarding the seismic performance of bridges Mataquito, Juan Pablo II, and Llacolen are presented. The bridges have been selected not only because clear evidence of liquefaction was found at their respective locations, but also because their seismic performance was very different, ranging from little to negligible damage to a larger and more distributed level of damage

Modelo de gestión logística y la eficiencia del presupuesto en la dirección de redes integradas de salud. Lima Este (DIRIS) – 2021

Objetivo: Determinar si existe relación entre el Modelo de Gestión Logística y la Eficiencia del Presupuesto en la Dirección de Redes Integradas de Salud Lima Este (DIRIS) - 2021. Métodos: La investigación posee una aplicación cuantitativa (coeficiente de correlación de Spearman, reclasificación de variables cualitativas a variables cuantificables y resultados comparativos entre el antes y después de la implementación de la solución propuesta), así como también el uso de una aplicación cualitativa ya que la investigación utilizó un instrumento de medición estandarizado con la escala de Likert que obtuvo resultados que fueron reclasificados utilizando escalas de medición que permitieron convertir las variables cualitativas obtenidas a variables cuantitativas para un mejor análisis. Resultados: Los resultados consolidados por la investigación han demostrado una relación alto y positva entre el modelo de gestión de la DIRIS y la eficiencia del presupuesto con una correlación del 77.98%. Conclusión: Quedó determinado que hay una relación significativa y positiva entre la Factibilidad del Eficiencia del presupuesto y el Padrón Nominal, debido a que al aplicar el test ji-cuadrado para un riesgo de 5% (Pvalor=0,00 < 0,05)

Site Effects and Damage Patterns

A set of observations on site effects and damage patterns from the M_w 8.8 Maule, Chile, earthquake is presented, focusing on identification of structural damage variability associated with nonuniform soil conditions and subsurface geology. Observations are reported from: (1) the City of Santiago de Chile (Américo Vespucio Norte Ring Highway, Ciudad Empresarial business park), (2) the Municipality of Viña del Mar, and (3) the City of Concepción, extending over 600 km along the Chilean coast. Reconnaissance information and ground motion recordings from the megathrust event are combined with site investigation data in the regions of interest. Comparisons against macroseismic observations related to uneven damage distribution from the M_w 8.0 1985 Valparaíso earthquake are discussed. Complexities associated with identifying the mechanics and underlying physical processes responsible for the manifestation of these effects are elucidated

Tailoring Organic-Organic Poly(vinylpyrrolidone) Microparticles and Fibers with Multiwalled Carbon Nanotubes for Reinforced Composites

Polymeric-based microparticles and fibers are tailorable for a wide range of common industrial and biomedical applications, while multiwalled carbon nanotubes (MWCNTs) are among the most useful macromolecules based on their outstanding electronic, mechanical, and optical properties at the nanoscale. If one combines these nanostructures with various polymeric precursors, their range of potential applications becomes even greater. One of the simplest and most affordable methods for fabricating micro- and nanostructures is electrospinning. Herein we demonstrate how MWCNTs may be used to produce tailor-made organic-organic poly(vinylpyrrolidone) (PVP) microparticles and fibers via electrospinning by studying their structural, vibrational, rheological, and mechanical properties' dependence on their solvent (ethanol (EtOH) or dimethylformamide (DMF)) and resulting morphology. Specifically, we find clear differences in morphologies from perfectly spherical and isolated microparticles to fibers mats, or a combination of fibers with entangled beads, with solvent type and concentration. On the basis of our findings, we propose that the mechanism governing the shape and size of the particles is a competition between the solvent's surface tension, dielectric constant, and viscoelastic properties. We show, based on both our experimental results and density functional theory (DFT) calculations, that OH functionalization of the MWCNTs is essential for achieving high PVP coverages and promoting the stability of the resulting PVP/MWCNT nanocomposite. Finally, by fabricating PVP/MWCNT fiber mats, we demonstrate that low concentrations (0.01-0.1 wt %) of MWCNTs led to a qualitative improvement (â250%) in the resulting mechanical properties, i.e., a reinforced composite. These results show how by controlling the solvent's dielectric constant, surface tension, and polymer concentration, one may produce tailor-made polymeric nanomaterials in combination with other organic/inorganic nanoparticles, i.e., silver, gold, or carbon allotropes, for next-generation applications

Highly efficient visible and near-IR photon pair generation with thin-film lithium niobate

Efficient on-chip entangled photon pair generation at telecom wavelengths is an integral aspect of emerging quantum optical technologies, particularly for quantum communication and computing. However, moving to shorter wavelengths enables the use of more accessible silicon detector technology and opens up applications in imaging and spectroscopy. Here, we present high brightness ($(1.6 \pm 0.3) \times 10^{9}$ pairs/mW/nm) visible-near-IR photon pair generation in a periodically poled lithium niobate nanophotonic waveguide. The degenerate spectrum of the photon pairs is centered at 811 nm with a bandwidth of 117 nm. The measured on-chip source efficiency of $(2.3\pm 0.5) \times 10^{11}$ pairs/mW is on par with source efficiencies at telecom wavelengths and is also orders of magnitude higher than the efficiencies of other visible sources implemented in bulk crystal or diffused waveguide-based technologies. These results represent the shortest wavelength of photon pairs generated in a nanophotonic waveguide reported to date by nearly an octave.Comment: Main text: 10 pages, 6 figures; Supplementary material: 5 pages, 3 figures. Author initials update

Methodology for the design and manufacture of devices medical, related to the sanitary emergency caused by covid-19

ABSTRACT The development of medical equipment is related to compliance with regulations, with the intention of safeguarding the physical integrity of patients, being able to ensure that a medical equipment complies with the regulations and can be registered with its respective authorization for use, it is a job long-term with the use of multiple resources. It is due to this characteristic that it is difficult for them to be able to register developments of medical equipment in most countries, either due to lack of infrastructure to carry out patient safety tests or due to the lack of regulations for the registration of medical equipment manufactured in their facilities of respective countries. In this research, a methodology is presented to be able to design medical equipment, considering the regulations and considerations regarding patient safety, as a result, a procedure based on the study of the market of similar equipment is presented in order to guarantee its possible registration and a matrix of technical information, to ensure compliance with regulations and patient safety

Improving glass-fiber epoxy composites via interlayer toughening with polyacrylonitrile/multiwalled carbon nanotubes electrospun fibers

The development of innovative engineered epoxy composites aiming to manufacture cost-efficient materials with reduced weight and enhanced physical properties remains as a current industrial challenge. In this work we report an original procedure for manufacturing glass-fiber epoxy reinforced nanocomposites (GFECs) by employing electrospun fiber-mats as a reinforcing phase. These fibers have been produced from polyacrylonitrile and multiwalled carbon nanotubes solutions. Optimal protocols are designed by combining Taguchi method with the morphological, structural and mechanical properties obtained by scanning electron microscopy, profilometry and tensile tests. It is demonstrated that GFECs fabricated using GF800 glass fiber show an improvement/enhancement of the mechanical properties with a fracture strain up to 500¿MPa (around 20% higher than the non-reinforced epoxy composite counterpart). It is also shown that GFECs fabricated using GF3M glass fiber exhibited a reduction of the roughness up to 56%, which corresponds with a roughness improvement from N8 to N7 following the guidelines provided by the ISO 1302. These results suggest that this type of nanocomposites would be suitable to be used in the aeronautics and automotive industries.This work was financially supported by the “Convocatoria de Ayudas a la Realización de Proyectos de Grupos de Investigación 2020-2021” of the Universidad Católica de Murcia (UCAM), Spain, Reference: PMFI-12/21. Pavel Ryzhakov, Jordi Pons-Prats, and Christian Narváez- Muñoz would also like to acknowledge the support of the Ministerio de Ciencia, Innovación y Universidades of Spain via the “Severo Ochoa Programme” for Centres of Excellence in R&D (reference: CEX2018-000797-S) given to the International Centre for Numerical Methods in Engineering (CIMNE). The work of Christian Narváez- Muñoz was financially supported by the “Severo Ochoa PhD Scholarship” Reference: PRE2020-096632. Pavel Ryzhakov and Jordi Pons-Prats are Serra Hunter fellows.Peer ReviewedPostprint (author's final draft

Effects of Ground Failure on Bridges, Roads, and Railroads

The long duration and strong velocity content of the motions produced by the 27 February 2010 Maule earthquake resulted in widespread liquefaction and lateral spreading in several urban and other regions of Chile. In particular, critical lifeline structures such as bridges, roadway embankments, and railroads were damaged by ground shaking and ground failure. This paper describes the effects that ground failure had on a number of bridges, roadway embankments, and railroads during this major earthquake