A Postprocessing methodology for direct normal irradiance forecasting using cloud information and aerosol load forecasts

A method for direct normal irradiance (DNI) forecasting for specific sites is proposed. It is based on the combination of a numerical weather prediction (NWP) model, which provides cloud information, with radiative transfer simulations fed with external aerosol forecasts. The NWP model used is the ECMWF Integrated Forecast System, and the radiative transfer information has been obtained from the Library of Radiative Transfer (libRadtran). Two types of aerosol forecasts have been tested: the global Monitoring Atmospheric Composition and Climate (MACC) model, which predicts five major components of aerosols, and the Dust Regional Atmospheric Model (BSC-DREAM8b) added to a fixed background calculated as the 20th percentile of the monthly mean of AERONET 2.0 observations from a different year. The methodology employed is valid for all meteorological situations, providing a stable and continuous DNI curve. The performance of the combined method has been evaluated against DNI observations and compared with the pure ECMWF forecasts at eight locations in the southern half of mainland Spain and the Canary Islands, which received high loadings of African dust for 2013 and 2014. Results for 1-day forecasts are presented. Although clouds play a major role, aerosols have a significant effect, but at shorter time scales. The combination of ECMWF and MACC forecasts gives the best global results, improving the DNI forecasts in events with high aerosol content. The regional BSC-DREAM8b yields good results for some extremely high dust conditions, although more reliable predictions, valid for any aerosol conditions, are provided by the MACC model

Lubrication performance of an ammonium cation-based ionic liquid used as an additive in a polar oil.

This paper studies the tribological behavior of the ionic liquid methyltrioctylammonium bis(trifluoromethylsulfonyl)imide ([N 1888 ][NTf 2 ]) as additive at different concentrations (1.25, 2.50, 3.75 and 5.00 wt%) in a polar base oil (diester). A tribometer using a ball-on-disk reciprocating configuration under fully flooded lubrication was used at a frequency of 15 Hz, at three different loads (40, 80 and 120 N), stroke length of 4 mm, and duration of 45 min. Worn surface on the disk was studied by confocal microscopy, SEM and XPS. Main results showed similar coefficient of friction for all lubricant samples; but different wear results were found at different loads, probably related with the chemical states found for fluorine on the worn surface and the temperature-dependent adsorption-desorption processes

Tribological behavior of oils additised with a phosphonium-derived ionic liquid compared to a commercial oil

Purpose: The purpose of this paper is to study the antifriction, antiwear and tribolayer formation properties of the trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate ionic liquid (IL) as additive at 1 wt.% in two base oils and their mixtures, comparing the results with those of a commercial oil. Design/methodology/approach: The mixture of the base oils used in the formulation of the commercial oil SAE 0W20 plus the IL was tested under rolling/sliding and reciprocating conditions to determine the so-called Stribeck curve, the tribolayer formation and the antifriction and antiwear behaviors. Findings: The use of this IL as additive in these oils does not change their viscosity; improves the antifriction and antiwear properties of the base oils, making equal or outperforming these properties of the SAE 0W20; and the thickness and formation rate of the tribolayer resulting from the IL-surface interaction is highly dependent on the type of base oil and influence on the friction and wear results. Originality/value: The use of this IL allows to replace partial or totally commercial antifriction and antiwear additives. Peer review: The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2020-0179/

On lower bounds using separable terms in interval B&B for one-dimensional poblems

Interval Branch-and-Bound (B&B) algorithms are powerful methods which aim for guaranteed solutions of Global Optimization problems. Lower bounds for a function in a given interval can be obtained directly with Interval Arithmetic. The use of lower bounds based on Taylor forms show a faster convergence to the minimum with decreasing size of the search interval. Our research focuses on one dimensional functions that can be decomposed into several terms (sub-functions). The question is whether using this characteristic leads to sharper bounds when based on bounds of the sub-functions. This paper deals with separable functions in two sub-functions. The use of the separability is investigated for the so-called Baumann form and Lower Bound Value Form (LBVF). It is proven that using the additively separability in the LBVF form may lead to a combination of linear minorants that are sharper than the original one. Numerical experiments confirm this improving behaviour and also show that not all separable methods do always provide sharper additively lower bounds. Additional research is needed to obtain better lower bounds for multiplicatively separable functions and to address higher dimensional problems

Characterization and Enhancement of Non-Invasive Recordings of Intestinal Myoelectrical Activity

Non

Costes de las inoculaciones accidentales en personal sanitario de un hospital

ResumenObjetivosEl objetivo de este estudio es calcular el coste medio a que asciende cada seguimiento de hepatitis B, C y VIH en el personal sanitario que ha sufrido una inoculación accidental, desagregar el coste en dependencia del estado serológico de la fuente e identificar los apartados que influyen en mayor grado en la cuantía de este resultado.MétodosSe realizó una descripción de costes. El programa post-exposición se modelizó en un árbol de decisión que combinaba probabilidades (porcentaje de cada tipo de fuente en función de su positividad a los tres virus e inmunización del accidentado frente a hepatitis B) y costes monetarios (pesetas del año 1994). Estos costes fueron: personal, laboratorio, farmacia, energéticos, limpieza, teléfono, material médico y de oficina, amortización y pérdidas productivas. Se realizó un análisis de sensibilidad en función del cumplimiento real del programa.ResultadosEl coste medio de cada inoculación fue de 39.564 ptas. (29.750 ptas. aplicando el análisis de sensibilidad), con un rango desde las 86.864 ptas. (fuente positiva a los tres virus y accidentado no inmunizado) a las 23.074 ptas. (fuente negativa a los tres virus). Si la fuente era hepatitis B positiva, el coste medio fue de 86.093 ptas. cuando el accidentado no estaba inmunizado y de 53.232 si lo estaba. La mayor parte del coste residió en las pruebas serológicas (rango del 72,8% al 87,7%).ConclusionesEl alto coste sugiere una evaluación adecuada del riesgo con el fin de evitar seguimientos innecesarios. El modelo utilizado permite conocer el coste de cada episodio potencialmente evitable y puede aplicarse en cualquier hospital con el objetivo de evaluar económicamente nuevos dispositivos preventivos.SummaryObjectivesThe aim of this study was to calculate the average cost of each hepatitis B, C and HIV follow-up carried out in the health personnel that have suffered an exposure to blood and body fluids and to estimate the cost for each of the different types of sources as wall as to identify the items that account for the main part of the cost.MethodsA cost analysis was carried out. The post-exposure programme was modelled in a decision tree combining probabilities (percentage of each type of source in dependence of its positivity for the three viruses and immunization state of the health personnel against hepatitis B) and monetary costs (pesetas from 1994). Costs included: salaries, laboratory, chemist, energy, cleaning, telephone, medical and office equipment, amortization and lost productivity. A sensitivity analysis was carried out with the real fulfillment of the programme.ResultsThe average cost was 39,564 ptas. (29,750 ptas. applying the sensitivity analysis), with a range from 86,864 ptas. (source positive for the three viruses and injured subject not immunized) to 23,074 ptas. (source negative for the three viruses). If the source was hepatitis B positive, the average cost was 86,093 ptas. when the injured subject was not immunized and 53,232 ptas. if he was immunized. Serologic tests account for the main part of the cost (range from 72.8% to 87.7%).ConclusionsHigh cost suggests an appropiate risk evaluation in order to avoid unnecessary follow-ups. The model used allows to know the cost of each potentially avoided episode and it could be used for any hospital in order to make an economical evaluation of new preventive devices

On interval branch-and-bound for additively separable functions with common variables

Interval branch-and-bound (B&B) algorithms are powerful methods which look for guaranteed solutions of global optimisation problems. The computational effort needed to reach this aim, increases exponentially with the problem dimension in the worst case. For separable functions this effort is less, as lower dimensional sub-problems can be solved individually. The question is how to design specific methods for cases where the objective function can be considered separable, but common variables occur in the sub-problems. This paper is devoted to establish the bases of B&B algorithms for separable problems. New B&B rules are presented based on derived properties to compute bounds. A numerical illustration is elaborated with a test-bed of problems mostly generated by combining traditional box constrained global optimisation problems, to show the potential of using the derived theoretical basis

Intrapericardial delivery of apa-microcapsules as promising stem cell therapy carriers in an experimental acute myocardial infarction model

The administration of cardiosphere-derived cells (CDCs) after acute myocardial infarction (AMI) is very promising. CDC encapsulation in alginate-poly-L-lysine-alginate (APA) could increase cell survival and adherence. The intrapericardial (IP) approach potentially achieves high concentrations of the therapeutic agent in the infarcted area. We aimed to evaluate IP therapy using a saline vehicle as a control (CON), a dose of 30 × 106 CDCs (CDCs) or APA microcapsules containing 30 × 106 CDCs (APA-CDCs) at 72 h in a porcine AMI model. Magnetic resonance imaging (MRI) was used to determine the left ventricular ejection fraction (LVEF), infarct size (IS), and indexed end diastolic and systolic volumes (EDVi; ESVi) pre-and 10 weeks post-injection. Programmed electrical stimulation (PES) was performed to test arrhythmia inducibility before euthanasia. Histopathological analysis was carried out afterwards. The IP infusion was successful in all animals. At 10 weeks, MRI revealed significantly higher LVEF in the APA-CDC group compared with CON. No significant differences were observed among groups in IS, EDVi, ESVi, PES and histopathological analyses. In conclusion, the IP injection of CDCs (microencapsulated or not) was feasible and safe 72 h post-AMI in the porcine model. Moreover, CDCs APA encapsulation could have a beneficial effect on cardiac function, reflected by a higher LVEF at 10 weeks. © 2021 by the authors. Licensee MDPI, Basel, Switzerland