Towards Dynamic Criticality-Based Maintenance Strategy for Industrial Assets

An asset’s risk is a useful indicator for determining optimal time of repair/replacement for assets in order to yield minimal operational cost of maintenance. For a successful asset management practice, asset-intensive organisations must understand the risk profile associated with their asset portfolio and how this will change over time. Unfortunately, in many risk-based asset management approaches, the only thing that is known to change in the risk profile of the asset is the likelihood (or probability) of failure. The criticality (or consequences of failure) of asset is assumed to be fixed and has considered as more or less a static quantity that is not updated with sufficient frequency as the operating environment changes. This paper proposes a dynamic criticality-based maintenance approach where asset criticality is modeled as a dynamic quantity and changes in asset’s criticality is used to optimize maintenance plans (e.g. determining the optimal repair time/replacement age for an asset over it life cycle period) to have a better risk management and cost savings. An illustrative example is used to demonstrate the effect of implementing dynamic criticality in determining the optimal time of repair for a bridge infrastructure. It is shown that capturing changes in the criticality of the bridge over time and using this understanding in the risk analysis of the bridge provided the opportunity for better maintenance planning resulting to reduction of the total risk

Evidencias psicométricas del cuestionario de interacción trabajo-familia (SWING-22) en adultos de Lima Metropolitana, 2021

El presente estudio se orientó a analizar las propiedades psicométricas del Cuestionario SWING-22, en adultos peruanos. El diseño fue instrumental con un tipo de investigación psicométrica, con muestreo no probabilístico por conveniencia lo cual comprendió de 324 observaciones, cuyas edades fueron de 18 a 65 años. Se realizó una V de Aiken que presentó buenos resultados, un análisis de reactivos donde se obtuvo que, las preguntas (13, 14, 15, 17, 19, 20, 21 y 22) no se ajustan al constructo. Por otro lado, en el AFC se obtuvo un modelo oblicuo con un CFI = (.99), TLI = (.98) SRMR = (.07), presentando buenos ajustes; además, una adecuada confiabilidad de (.88) y el Omega de McDonald (.96). En sus dimensiones, INTF (.93), INFT (.87), IPTF (.78) y IPFT (.84), por ello, se concluyó que presenta buenos ajustes, aunque, presenta deficiencias en algunos reactivos. Finalmente, se recomienda realizar una adaptación lingüística, ampliación de la muestra y utilizar otros métodos de análisis de datos para un mejor análisis psicométrico

OPTIMIZACIÓN DE LA MEZCLA ENTRE LDPE Y PLA PARA LA CARACTERIZACIÓN DE EMPAQUES PLÁSTICOS DE UN SOLO USO

El siguiente artículo de investigación muestra el estudio en el desarrollo de una mezcla entre un plástico sintético LDPE (Polietileno de Baja Densidad) derivado del petróleo y un polímero natural PLA (Ácido Poliláctico) derivado del ácido láctico. Con la unión de estos dos materiales se pretende crear un compuesto, donde ambos materiales se comporten como uno solo, añadiendo agentes de acoplamiento y estabilizador térmico para poder transformarlo en un empaque plástico de un solo uso. Este producto se desarrollará con muestras de película plástica, utilizando diferentes proporciones entre LDPE y PLA con el fin de determinar la mezcla ideal que permita la verificación de dispersión, distribución y homogenización. &nbsp

Variation in the concentration of heavy metals due to rains and floods in the Rimac river basin, Lima-Peru

The urban agglomeration of Lima and Callao is the second largest city in the world located in a desert, and its supply depends on three small rivers, the Rímac River being the one with the greatest water supply, affected by contamination by mining tailings, sewage and Solid waste. In order to know the climatological and hydrographic conditions that favor the concentration of heavy metals in the water, the relationship between rainfall, water discharges and concentration of aluminum, cadmium, iron and lead in the Rímac River hydrographic system in the period 2018-2021. For which data processing was carried out from six meteorological stations, a water quality monitoring point and four limnimetric stations, through dynamic tables. As a result, it was found that the concentration of heavy metals is higher in the lower basin when rainfall and river level increase in localities of the Alto Rímac sub-basin, which presents intense mining activity, unlike the Santa Eulalia sub-basin. river where there are no large-scale mining operations, whose records present weaker relationships with the concentration of heavy metals. In conclusion, the highest concentration of heavy metals in the lower basin occurs during the months with the most intense rains in the headwaters of the basin, as the dragging capacity increases during the flooding of rivers and streams, allowing concentrations to exceed up to 120 times the quality standards for the production of drinking water

La información científica en la televisión

En esta comunicación se presentan unos materiales en los que se aprovecha el potencial de las noticias científicas emitidas por televisión para elaborar unidades didácticas que se pueden utilizar en las clases de Ciencias de la Naturaleza de los últimos cursos de ESO o en la materia CMC de Bachillerato. Los alumnos aprenden a analizar la información presente en esas noticias señalando sus aspectos positivos y negativos, profundizando en el conocimiento de los conceptos implicados

Pulsatile flow in coronary bifurcations for different stenting techniques

The objective of this work is to analyze the local hem odynamic changes caused in a coronary bifurcation by three different stenting techniques: simple stenting of the main vessel, simple stenting of the main vessel with kissing balloon in the side branch and culotte. To carry out this study an idealized geometry of a coronary bifurcation is used, and two bifurcation angles, 45º and 90º, are chosen as representative of the wide variety of re al configurations. In order to quantify the influence of the stenting technique on the local blood flow, both numeri- cal simulations and experimental measurements are performed. First, steady simulations are carried out with the commercial code ANSYS-Fluent, and then, experimental measurements with PIV (Particle Image Velocimetry) obtained in the laboratory are used to validate the numerical simulation. The steady computational simulations show a good overall agreement with the experimental data. Second, pulsatile flow is considered to take into account the tran- sient effects. The time averaged wall shear stress, scillatory shear index and pressure drop obtained numerically are used to compare the behavior of the stenting techniques

La información científica en la televisión

En esta comunicación se presentan unos materiales en los que se aprovecha el potencial de las noticias científicas emitidas por televisión para elaborar unidades didácticas que se pueden utilizar en las clases de Ciencias de la Naturaleza de los últimos cursos de ESO o en la materia CMC de Bachillerato. Los alumnos aprenden a analizar la información presente en esas noticias señalando sus aspectos positivos y negativos, profundizando en el conocimiento de los conceptos implicados

Trajectories of Symptom Dimensions in Short-Term Response to Antipsychotic Treatment in Patients with a First Episode of Non-Affective Psychosis

Background Trajectory patterns of positive, disorganized and negative dimension symptoms during antipsychotic treatment in drug-naive patients with first-episode psychosis have yet to be examined by using naturalistic data. Method This pragmatic clinical trial randomized 161 drug-naive patients with a first episode of psychosis to olanzapine, risperidone or haloperidol. Patients were assessed with the Scale for the Assessment of Negative Symptoms (SANS) and Positive Symptoms (SAPS) at baseline and at the end of weeks 1, 2, 3, 4 and 6 of antipsychotic treatment. Censored normal models of response trajectories were developed with three dimensions of the SAPS-SANS scores (positive, disorganized and negative) in order to identify the different response trajectories. Diagnosis, cannabis use, duration of untreated psychosis (DUP), smoking and antipsychotic class were examined as possible predictive variables. Results Patients were classified in five groups according to the positive dimension, three groups according to the disorganized dimension and five groups according to the negative dimension. Longer DUPs and cannabis use were associated with higher scores and poorer responses in the positive dimension. Cannabis use was associated with higher scores and poorer responses in the disorganized dimension. Only schizophrenia diagnosis was associated with higher scores and poorer responses in the negative dimension. Conclusions Our results illustrate the heterogeneity of short-term response to antipsychotics in patients with a first episode of psychosis and highlight markedly different patterns of response in the positive, disorganized and negative dimensions. DUP, cannabis use and diagnosis appeared to have a prognostic value in predicting treatment response with different implications for each dimension