Modelling of Diesel fuel properties through its surrogates using Perturbed-Chain, Statistical Associating Fluid Theory

The Perturbed-Chain, Statistical Associating Fluid Theory equation of state is utilised to model the effect of pressure and temperature on the density, volatility and viscosity of four Diesel surrogates; these calculated properties are then compared to the properties of several Diesel fuels. Perturbed-Chain, Statistical Associating Fluid Theory calculations are performed using different sources for the pure component parameters. One source utilises literature values obtained from fitting vapour pressure and saturated liquid density data or from correlations based on these parameters. The second source utilises a group contribution method based on the chemical structure of each compound. Both modelling methods deliver similar estimations for surrogate density and volatility that are in close agreement with experimental results obtained at ambient pressure. Surrogate viscosity is calculated using the entropy scaling model with a new mixing rule for calculating mixture model parameters. The closest match of the surrogates to Diesel fuel properties provides mean deviations of 1.7% in density, 2.9% in volatility and 8.3% in viscosity. The Perturbed-Chain, Statistical Associating Fluid Theory results are compared to calculations using the Peng–Robinson equation of state; the greater performance of the Perturbed-Chain, Statistical Associating Fluid Theory approach for calculating fluid properties is demonstrated. Finally, an eight-component surrogate, with properties at high pressure and temperature predicted with the group contribution Perturbed-Chain, Statistical Associating Fluid Theory method, yields the best match for Diesel properties with a combined mean absolute deviation of 7.1% from experimental data found in the literature for conditions up to 373°K and 500 MPa. These results demonstrate the predictive capability of a state-of-the-art equation of state for Diesel fuels at extreme engine operating conditions

Simulation of transcritical Diesel jets using the PC-SAFT EoS

A numerical framework has been developed to simulate Diesel injections using the Perturbed Chain Statistical Associating FluidTheory (PC-SAFT) equation of state (EoS). The Diesel is modelled as a mixture composed by a rather small number of components that accurately replicate its properties. The composition of the Diesel surro-gates employed are divided into two typesdepending on how closely they approximatetherealDiesel composition. Despite of applying anadvanced molecular theory, practical simulations can be performed reducing the number of times the EoSis solved by calculating the pressure and sonic fluid velocity in thecell centers and performing a reconstruction of these variables at the cell faces. Thismethodologyis found to smooth-out the spurious pressure oscillations associated with conservative schemes used along real-fluid EoS.Furthermore, two shock tube prob-lemsarepresentedto validate the hyperbolic part of the numerical frameworkand evaluate how the number of compounds of theDieselsurrogateemployedaffects theaccuracy of the numerical results.Finally,a two-dimen-sional simulation of afour component Diesel surrogate injection is includedto demonstrate the capability of the developed method to predict Diesel fuel-airmixing.Phase separation isbeyond the scope of this research

Simulation of transcritical fluid jets using the PC-SAFT EoS

The present paper describes a numerical framework to simulate transcritical and supercritical flows utilising the compressible form of the Navier–Stokes equations coupled with the Perturbed Chain Statistical Associating Fluid Theory (PC-SAFT) equation of state (EoS); both conservative and quasi-conservative formulations have been tested. This molecular model is an alternative to cubic EoS which show low accuracy computing the thermodynamic properties of hydrocarbons at temperatures typical for high pressure injection systems. Liquid density, compressibility, speed of sound, vapour pressures and density derivatives are calculated with more precision when compared to cubic EoS. Advection test cases and shock tube problems are included to show the overall performance of the developed framework employing both formulations. Additionally, two-dimensional simulations of nitrogen and dodecane jets are presented to demonstrate the multidimensional capability of the developed model

Thermalization and Cooling of Plasmon-Exciton Polaritons: Towards Quantum Condensation

We present indications of thermalization and cooling of quasi-particles, a precursor for quantum condensation, in a plasmonic nanoparticle array. We investigate a periodic array of metallic nanorods covered by a polymer layer doped with an organic dye at room temperature. Surface lattice resonances of the array---hybridized plasmonic/photonic modes---couple strongly to excitons in the dye, and bosonic quasi-particles which we call plasmon-exciton-polaritons (PEPs) are formed. By increasing the PEP density through optical pumping, we observe thermalization and cooling of the strongly coupled PEP band in the light emission dispersion diagram. For increased pumping, we observe saturation of the strong coupling and emission in a new weakly coupled band, which again shows signatures of thermalization and cooling.Comment: 8 pages, 5 figures including supplemental material. The newest version includes new measurements and corrections to the interpretation of the result

Supercritical and transcritical real-fluid mixing using the PC-SAFT EOS

A numerical framework has been developed to simulate the mixing of supercritical and transcritical fluids using an equation of state based on statistical associating fluid theory. In a Diesel engine the liquid fuel is injected into supercritical air. After the injection, the Diesel is heated over its critical temperature reaching a supercritical state. Modelling real-fluid effects is critical in order to properly characterize the air/fuel mixing in the combustion chamber. By using the PC-SAFT EoS (Perturbed Chain Statistical Association Fluid Theory Equation of State) real fluids effects can be taken into account in a CFD simulation. The PC-SAFT EoS shows best results than cubic EoS computing liquid density, compressibility, speed of sound, vapor pressures and density derivatives. Unlike cubic EoS, this model accounts for the shape and size of the molecules. Gas, liquid, supercritical and vapor-liquid equilibrium states can be simulated. PT FLASH (Isothermal Multiphase Flash Calculation) is applied to compute the phase diagram used by the code. Shock tube problems were conducted in a wide range of pressures and densities using n-dodecane to show the capability of the developed algorithm. The results were compared with the solution of an exact Riemann solver which has the PC-SAFT EoS implemented showing a high degree of agreement. In addition, a two-dimensional simulation of supercritical nitrogen jet mixing was carried out to check the multidimensional capability of the code

Designing for Risk Assessment Systems for Patient Triage in Primary Health Care:A Literature Review

Background: This literature review covers original journal papers published between 2011 and 2015. These papers review the current status of research on the application of human factors and ergonomics in risk assessment systems’ design to cope with the complexity, singularity, and danger in patient triage in primary health care. Objective: This paper presents a systematic literature review that aims to identify, analyze, and interpret the application of available evidence from human factors and ergonomics to the design of tools, devices, and work processes to support risk assessment in the context of health care. Methods: Electronic search was performed on 7 bibliographic databases of health sciences, engineering, and computer sciences disciplines. The quality and suitability of primary studies were evaluated, and selected papers were classified according to 4 classes of outcomes. Results: A total of 1845 papers were retrieved by the initial search, culminating in 16 selected for data extraction after the application of inclusion and exclusion criteria and quality and suitability evaluation. Conclusions: Results point out that the study of the implications of the lack of understanding about real work performance in designing for risk assessment in health care is very specific, little explored, and mostly focused on the development of tool

Effect of realistic multicomponent diesel surrogates on predicted in-nozzle flow and cavitation

In-nozzle flow dominates primary break-up characteristics and therefore the combustion efficiency. However, predictive methods of the internal nozzle flow and its link with the spray characteristics have traditionally used constant fuel properties, which may lead to large inaccuracies. Surprisingly enough, neither the effects of using realistic surrogates have been closely examined. In this work, the fuel property variation as function of pressure and temperature of three diesel surrogates are modelled using the PC-SAFT state-of-the-art EoS; these include n-dodecane and two mixtures comprising four and eight components, named V0 and V1 respectively, based on a grade no. 2 diesel emissions-certification fuel. Then, the surrogates used in simulations for a common rail 5-hole tip injector. The needle is assumed to be still at a lift of 105µm, similar to that used for pilot injections. The injector operating pressure is 180MPa and the collector back pressure is 5MPa. Heat effects are omitted and no turbulence model is used. The bulk fluid is considered to be a single phase whose density varies according to a barotropic-like scheme, following an isentropic line. Results show that the mixture surrogates V0 and V1 have a greater vapour pressure than that of n-dodecane, although they are significantly heavier both in density and viscosity. Predicted cavitation clouds occupied a ∼14% larger volume for V1 than that for n-dodecane. Slight differences were observed on mass flux, where V1 gave an increase of ∼7% with respect to n-dodecane. Interestingly, the amount of vaporised components which appear simultaneously in the two mixtures were not the same, which may show that there exists an interaction between the components during the vaporisation process. Despite its exploratory nature, this study offers some insight for the first time into the use of complex EoS and surrogate mixtures, which may be worth to capture the particular properties of diesel fuel during high pressure injections

Component-resolved diagnosis of pollen allergy based on skin testing with profilin, polcalcin and lipid transfer protein pan-allergens

BACKGROUND Allergy diagnosis needs to be improved in patients suffering from pollen polysensitization due to the existence of possible confounding factors in this type of patients. OBJECTIVE To evaluate new diagnostic strategies by comparing skin responses to pan-allergens and conventional allergenic extracts with specific IgE (sIgE) to purified allergen molecules. METHODS One thousand three hundred and twenty-nine pollen-allergic patients were diagnosed by a combination of an in vitro method with a panel of 13 purified allergens, including major allergens and pan-allergens, using a high-capacity screening technology (ADVIA-Centaur®) and skin prick test (SPT) to pan-allergens and conventional extracts. RESULTS There was a high concordance (κ index) between in vitro (sIgE to major allergens) and in vivo (SPT to conventional extracts) methods in patients who were not sensitized to pan-allergens, but SPT with conventional extracts failed to diagnose patients with sensitization to pan-allergens. In patients who were simultaneously sensitized to polcalcins and profilins, there was a duplication both in the number of sensitizations to major allergens and in the years of disease evolution. There was a statistical association between sensitization to profilins and/or lipid transfer proteins and food allergy (P<0.0001). CONCLUSION The novel diagnostic strategy has proven to be a valuable tool in daily clinical practice. Introduction of routine SPT to pan-allergens is a simple and feasible way of improving diagnostic efficacy. Patients sensitized to pan-allergens should be tested by an adequate panel of allergenic molecules in order to identify the allergens that are responsible for the allergic disease

Revision of European Ecolabel Criteria for Tourist Accommodation and Campsite services. Final criteria proposal

The EU Ecolabel criteria form key voluntary policy instruments within the European Commission’s Sustainable Consumption and Production and Sustainable Industrial Policy (SCP/SIP) Action Plan and the Roadmap for a Resource-Efficient Europe. The Roadmap seeks to move the economy of Europe onto a more resource efficient path by 2020 in order to become more competitive and to create growth and employment. The EU Ecolabel promotes the production and consumption of products with a reduced environmental impact along the life cycle and is awarded only to the best (environmental) performing products in the market. The objective of this project is to revise the two existing EU Ecolabel criteria relating to tourism services: tourist accommodation services and camp site services. These criteria will be merged, to form one set of criteria for tourist accommodation. Since the last revision of the criteria (2009/578/EC & 2009/564/EC: Commission Decisions of 9 July 2009), a number of important changes have taken place in this area, including policy changes, changes in the market and changes in the perception of tourism’s environmental impacts. This report outlines the factors which may lead to a change in criteria, through updates, revisions or the addition of new criteria. This technical report is aimed at providing a sound base to the revision process of the EU Ecolabel criteria for Tourist Accommodation (2009/578/EC) and Camp Site Services (2009/564/EC). The main purpose of this document is to evaluate the current criteria and discuss if the criteria are still relevant or should be revised. This document was developed to undergo the stakeholder consultation, which is crucial to come up with criteria adapted to the market reality while being able to select the best environmental performance products available on the market.JRC.B.5-Circular Economy and Industrial Leadershi