Experimental characterisation of dry friction isolators for shock and vibration

Abstract Shock and vibration are a source of failures in harsh environments such as military, naval and aerospace applications; thus, the use of vibration isolators is extended. Cable isolators are known for their high-energy storage and dissipation properties making them suitable for shock isolation and low frequency vibration. Such isolators present nonlinear stiffness in different directions such as compression, roll and shear, as well as dry friction damping. Although their use is extended, the knowledge regarding their dynamic response under shock loading is very limited. This work presents an overview of the vibration and shock isolation performance of several cable isolators under axial loading. The main contribution of the paper is to investigate and discuss the shock response of the isolators when subjected to pulses of different durations, finding improved isolation performance when compared to an equivalent linear system. Furthermore, a mathematical model based on a Duffing oscillator is proposed as a first approximation, in order to reflect the nonlinear stiffness and predict the shock response, thus facilitating further design and selection of improved shock isolation systems. Keywords Shock, wire rope, isolation, damping, vibration isolatio

La guitarra en el bolero y vals criollo en la costa del Pacífico

El presente trabajo consiste en la composición, construcción de arreglos y producción musical de un repertorio de 7 piezas en formato canción y una pieza instrumental (formato de banda: 3 voces, dos guitarras melódicas, una guitarra armónica, bajo y percusión), planteadas dentro del marco de la música latinoamericana popular, específicamente en los géneros bolero y vals criollo. La elección de estos géneros responde a una relación intrínseca y natural por origen de quien suscribe con la música popular latinoamericana de la costa del Pacífico. En Chile, el bolero y el vals representan, como dos géneros predominantes, una fuerte expresión en la cultura popular y tienen en común a la guitarra criolla como instrumento motor.Facultad de Arte

Caracterización de la actividad física y las organizaciones que prestan servicios deportivos en el municipio de Apía 2012

El municipio de Apia Risaralda de acuerdo a las metas nacionales de desarrollo humano, convivencia y la paz, demanda programas y proyectos que le permita acceder a prácticas deportivas a través del accionar de las organizaciones formales o no, que indirectamente contribuyen al crecimiento de la práctica de la actividad física en el municipio. Contribuyendo así al cumplimiento del derecho al deporte y la recreación como necesidad fundamental de la sociedad, constituida como gasto público social según acto legislativo 002 del 2000. Teniendo en cuenta el desconocimiento de la Administración Municipal en materia fortalecimiento, fomento o promoción y posicionamiento y liderazgo deportivo de las instituciones prestadoras del servicio y de la práctica matutina de la actividad física, se hizo necesario por medio de una investigación de tipo descriptiva, conocer el estado actual de las Organizaciones deportivas y de la práctica de actividad física, bajo la luz de los lineamientos de política nacional en el sector. La población encuestada se divide en 2 universos: 371 habitantes que practican Actividad física y 9 Organizaciones que prestan servicios deportivos a la comunidad del municipio de Apía. Los resultados de la presente investigación, permiten presentar un referente teórico sobre la percepción de la comunidad como elemento fundamental en la concepción, planeación y formulación de políticas públicas deportivas y recreativas del municipio

Avance y fortalecimiento de los sistemas anticorrupción desde la ética pública: un enfoque de política pública

El artículo se inserta en la discusión sobre las políticas anticorrupción y la ética pública. Sus aportaciones se encuentran divididas en dos: en primer lugar, en relación con el avance en la conformación de los sistemas estatales anticorrupción, para ello se realiza un análisis cuantitativo de ponderación para evaluar su avance hasta finales de 2018. En segundo lugar, se realiza una revisión de instrumentos de política anticorrupción desde una perspectiva de la ética pública, insistiendo en diferenciar e integrar acciones destinadas a reducir la discrecionalidad de los funcionarios y aquellas que tienen que ver con la promoción de un comportamiento ético

Electro-concentration for chemical-free nitrogen capture as solid ammonium bicarbonate

Source-separated urine is a promising stream for nutrient capture using electrochemical technologies. It contains the majority of macronutrients present in municipal wastewater in a concentrated, high ionic conductivity liquid and in N:P:K ratios suitable for agricultural application. The purpose of this study was to recover nutrients from urine, and particularly nitrogen as a solid without any chemical addition. Simulated source-separated urine was concentrated using a three-compartment electrochemical system, applying a range of current densities and feed compositions. Electro-concentration into a liquid concentrate reached maximum recovery of 72:61:79% for N:P:K, respectively, from a synthetic feed simulating ureolysed and digested urine, with a specific electrical energy consumption of 47 MJ/kg N and current efficiency of 67% for ammonium. Cooling the concentrate to −18 °C resulted in solid ammonium bicarbonate crystal formation in samples with high ammonium bicarbonate ionic product and high relative ammonium bicarbonate ionic strength. Precipitation started to occur when ammonium bicarbonate ionic product was higher than 2.25 M and ammonium bicarbonate accounted for more than 62% of the total ionic strength of the feed. The maximum observed nitrogen recovery into solid ammonium bicarbonate reached 17% using a current density of 100 A m. Based on these results, electro-concentration is a promising technology for urine nutrient capture. However, capture as solid ammonium bicarbonate is feasible only if higher recovery efficiencies are achieved by removing competing ions

Modelling and techno-economic assessment of (bio)electrochemical nitrogen removal and recovery from reject water at full WWTP scale

At conventional wastewater treatment plants (WWTPs), reject waters originating from the dewatering of anaerobically digested sludge contain the highest nitrogen concentrations within the plant and thereby have potential for realising nitrogen recovery in a reusable form. At the same time, nitrogen removal from reject waters has potential to reduce the energetic and chemical demands of the WWTP due to a reduced nutrient load to the activated sludge process. In recent years, (bio)electrochemical methods have been extensively studied for nitrogen recovery from reject waters in laboratory-scale but not yet implemented in real WWTP environments, particularly due to concerns about the need for large capital investments. This study assessed the techno-economic feasibility of retrofitting a (bio)electrochemical nitrogen removal and recovery (NRR) unit into the reject water circulation line of a full-scale WWTP through modelling. Data from laboratory-scale (bio)electroconcentration ((B)EC) experiments was used to construct a simple, semi-empirical model block integrated into the Benchmark Simulation Model No. 2 (BSM2) simulating a generalised WWTP. The effects of nitrogen removal from the reject water on both the effluent quality and operational costs of the WWTP were assessed and compared to the BSM2 performance without an NRR unit. In all studied scenarios, the effluent quality index was improved by 4–11%, while both the aeration (7–19% decrease) and carbon (24–71%) requirements were reduced. The additional energy consumed by the NRR unit increased the total operational cost index by >18%, but the revenue assumed for the generated nutrient product (20 EUR kgN−1) was enough to make the BEC-NRR scenarios at realistically low current densities (1 and 5 A m−2) economically attractive compared to the control. A sensitivity analysis revealed that electricity price and nutrient product value had the most notable effects on the feasibility of the NRR unit. The results suggest a key factor in making (bio)electrochemical NRR economically viable is to reduce its electricity consumption further, while the anticipated increases in nitrogen fertiliser prices can help accelerate the adoption of these methods in larger scale.publishedVersionPeer reviewe

Biosilo de residuos de merluza y harina de cebada fermentados con bacterias ácido lácticas seleccionadas

Suitability of Lactococcus lactis Tw34 and Lactobacillus plantarum Lb7 as bio-silage inoculants was studied. Experiments were carried out with a mixture of hake (Merluccius hubbsi) by-products and barley meal fermented during 7 days. A sample acidified with lactic acid was used as control. In biological mixtures, the pH dropped below 5,0 after 2 days of fermentation and remained stable until the end of the experience. Maximum populations (> 109 CFU/g) were reached after 5 days of incubation at 18°C. Water soluble peptides concentration increased during the 7 days of incubation and no significant differences (p < 0,05) were found between the control and both bio-silage. Trichloroacetic acid soluble peptides concentrations of biosilages were higher than the control (p > 0,05). After 7 days, phosphorous concentrations reached 2.26 and 2,42 g/100 g in bio-silages fermented with Lc. lactis Tw34 and Lb. plantarum Lb7, respectively, while control values remains almost stable (1,61 g/100 g). At the end of the experience, inhibitory activity of trypsin was abolished in both bio-silage while in control sample antinutritional factors remained active. The results indicated the feasibility of the use of the selected mixture as substrate for bio-silage production and the effectiveness Lc. lactis Tw34 and Lb. plantarum Lb7 as inoculants.Se estudió la capacidad como inoculantes de biosilo de Lactococcus lactis Tw34 y  Lactobacillus plantarum Lb7. Los experimentos se llevaron a cabo con una mezcla de subproductos de merluza (Merluccius hubbsi) y harina de cebada, fermentada durante 7 días. Como control se utilizó una muestra acidificada con ácido láctico. En las  mezclas biológicas, el pH disminuyó por debajo de 5,0 después de 2 días de fermentación y permaneció estable hasta el final de la experiencia. La población máxima (>109 UFC/g) se alcanzó después de 5 días de incubación a 18°C. La concentración de péptidos solubles en agua aumentó durante los 7 días de incubación y no hubo diferencias significativas (p < 0,05) entre el control y ambos biosilos. Las concentraciones de  péptidos solubles en ácido tricloroacético de los biosilos fueron superiores al control (p > 0,05). Después de 7 días, las concentraciones de fósforo alcanzadas fueron 2,26 y 2,42 g /100 g en los biosilos fermentados con Lc. lactis Tw34 y Lb. plantarum Lb7 respectivamente, mientras que en el control los valores permanecieron casi estables (1,61 g/100 g). Al final de la experiencia, la actividad inhibitoria de tripsina fue suprimida en ambos biosilos mientras que, en el control los factores antinutricionales seguían siendo activos. Los resultados indican la factibilidad del uso de la mezcla seleccionada como sustrato para la producción de biosilo y la eficacia de Lc. lactis Tw34 y Lb. plantarum Lb7 como inoculantes

Predicting the outcome of patients with subarachnoid hemorrhage using machine learning techniques

Background: Outcome prediction for subarachnoid hemorrhage (SAH) helps guide care and compare global management strategies. Logistic regression models for outcome prediction may be cumbersome to apply in clinical practice. Objective: To use machine learning techniques to build a model of outcome prediction that makes the knowledge discovered from the data explicit and communicable to domain experts. Material and methods: A derivation cohort (n = 441) of nonselected SAH cases was analyzed using different classification algorithms to generate decision trees and decision rules. Algorithms used were C4.5, fast decision tree learner, partial decision trees, repeated incremental pruning to produce error reduction, nearest neighbor with generalization, and ripple down rule learner. Outcome was dichotomized in favorable [Glasgow outcome scale (GOS) = I–II] and poor (GOS = III–V). An independent cohort (n = 193) was used for validation. An exploratory questionnaire was given to potential users (specialist doctors) to gather their opinion on the classifier and its usability in clinical routine. Results: The best classifier was obtained with the C4.5 algorithm. It uses only two attributes [World Federation of Neurological Surgeons (WFNS) and Fisher’s scale] and leads to a simple decision tree. The accuracy of the classifier [area under the ROC curve (AUC) = 0.84; confidence interval (CI) = 0.80–0.88] is similar to that obtained by a logistic regression model (AUC = 0.86; CI = 0.83–0.89) derived from the same data and is considered better fit for clinical use.This work was supported in part by the Spanish Ministries of Science under Grant TRA2007-67374-C02-02 and Health under Grant FIS PI 070152. The work of A. Lagares and J.F. Alen was supported by the Fundación Mutua Madrileña

Fate of pharmaceuticals and PFASs during the electrochemical generation of a nitrogen-rich nutrient product from real reject water

Recycling vital macronutrients, such as nitrogen, from wastewaters back to fertiliser use is becoming essential to ensure sustainable agricultural practices. Technologies developed for such purposes are typically evaluated for their capacity to recover nutrients; however, the presence of contaminants of emerging concern (CECs) in these waste-derived nutrient products must not be overlooked. In this study, nitrogen was recovered from real anaerobically digested municipal sewage sludge reject water using a novel set-up combining membrane-based electroconcentration (EC) with electrochemical advanced oxidation processes (EAOPs). Simultaneously, the fate of five spiked pharmaceuticals (carbamazepine, ciprofloxacin, diclofenac, erythromycin and metoprolol) as well as ten indigenous perfluoroalkyl substances (PFASs) was investigated. The EC-EAOP system was effective in up-concentrating nitrogen ca. 13 times to a final concentration of 12.7 ± 0.8 g L−1 in the nutrient product. At the same time, no up-concentration was observed for the pharmaceuticals and their concentrations in the recovered concentrated remained at ≤ 3.4 ± 1.3 µg L−1. The EAOPs were the main transformation mechanism for all the pharmaceuticals at 33–88% efficiency, while diclofenac also notably adsorbed in the system (30 ± 1.4%). Out of the ten studied PFASs, only three were found in the recovered nutrient concentrate, albeit at very limited concentrations of ≤ 0.024 ± 0.013 µg L−1. The EAOPs were found to degrade longer-chain PFASs into their shorter-chain counterparts. The low contaminant concentrations in the nutrient product pose a reduced risk for soil contamination compared to, e.g., biosolids that are more typically used as fertilisers.publishedVersionPeer reviewe

La imagen y la narrativa como herramientas para el abordaje psicosocial en escenarios de violencia en los Departamentos de Nariño y Putumayo.

La imagen y la narrativa como herramientas para el abordaje psicosocial en escenarios de violencia en los Departamentos de Nariño y Putumayo.El trabajo realizado da cuenta del análisis y valoración de eventos psicosociales traumáticos causados por el conflicto armado colombiano en la persona de Ana Ligia y la Comunidad Cacarica, a partir de estos relatos realizamos la construcción de preguntas, estratégicas, circulares y reflexivas con el objetivo de hacer un acercamiento psicosocial en la superación de las condiciones de victimización. En el caso de la Comunidad Cacarica generaremos reflexiones y propusimos estrategias de acompañamiento. Terminamos con un informe reflexivo y analítico de la experiencia realizada en los Departamentos de Nariño y Putumayo de Foto Voz, herramienta de diagnóstico que nos permitió ir más de allá favoreciendo la lectura de realidades de violencia en la ciudad de Pasto, La Cruz, Puerres, y el Departamento del Putumayo.The work done accounts for the analysis and assessment of traumatic psychosocial events caused by the Colombian armed conflict in the person of Ana Ligia and the Cacarica Community, from these stories we carry out the construction of questions, strategic, circular and reflective with the objective of make a psychosocial approach in overcoming victimization conditions. In the case of the Cacarica Community, we will generate reflections and propose accompanying strategies. We finished with a reflective and analytical report of the experience carried out in the Departments of Nariño and Putumayo of Foto Voz, a diagnostic tool that allowed us to go further, favoring the reading of realities of violence in the city of Pasto, Puerres, and the Department of Putumayo