Developments in consequence modelling of accidental releases of hazardous materials

The modelling of consequences of releases of hazardous materials in the Netherlands has mainly been based on the “Yellow Book”. Although there is no updated version of this offi cial publication, new insights have been developed during the last decades. This article will give an overview of new developments in consequence modelling, focussing on fi re modelling

Modelling of the plume rise phenomenon due to warehouse fires considering penetration of the mixing layer

PresentationThe present paper describes the theory behind the “plume rise from warehouse fires model” as implemented in the software package EFFECTS. This model simulates the rising of buoyant plumes due to the density difference between the hot combustion products and the ambient air. The plume rise model calculates the maximum height at which the released material will be in equilibrium with the density of the air, and presents the resulting trajectory of the plume, including hazard distances to specific concentration threshold levels. These parameters will be determined depending on the windspeed, atmospheric stability class and the fire’s convective heat production, leading to potential penetration of the mixing layer. Additionally, the ‘penetration fraction’ is assessed which expresses the amount of plume penetrating the mixing layer. If the convective heat of production is sufficient to penetrate the mixing layer, the smoke plume will be trapped above the mixing layer. When this occurs, the (potentially toxic) combustion products do not disperse back below the mixing layer, thus, the individuals at ground level are not exposed to the harmful combustion products. If the convective heat of production is not sufficient to penetrate the mixing layer, the smoke plume may experience the so-called reflection phenomena which will trap the smoke plume below the mixing layer. This could have more dangerous consequences for individuals who then might be exposed to harmful combustion products at ground level. Moreover, this paper includes the validation of the model against experimental data as well as to other widely validated mathematical models. The experiments and mathematical models used for the validation are described, and a detailed discussion of the results is included, with a statistical and graphical comparison against the field data

Improvement of the Effects Dispersion Model for Under Expanded Turbulent Jets

Recently, the dispersion model in EFFECTS was updated and extensively validated for light gas situations including jet releases and lifting plumes. In the present paper the modifications for gaseous turbulent jets will be discussed. This includes the full release velocity range from low subsonic to supersonic flow under highly under expanded conditions which are highly relevant for the high-pressure storage of hydrogen. In particular, a new model for the calculation of the expanded diameter in combination with an adapted implementation of the Chen and Rodi model was developed. The models were validated against a wide range of experimental classical and recent data sets including concentration and velocity data. This also includes a wide range of initial densities from lighter than air to heavy gas which will be discussed in this paper. The simulations show excellent agreement with experimental data resulting in less conservative predictions compared with the previous models

Corona and Financial Stability 4.0: Implementing a European Pandemic Equity Fund

This Policy Letter presents a proposal for designing a program of government assistance for firms hurt by the Coronavirus crisis in the European Union (EU). In our recent Policy Letter 81, we introduced a new, equity-type instrument, a cash-against-tax surcharge scheme, bundled across firms and countries in a European Pandemic Equity Fund (EPEF). The present Policy Letter 84 focuses on the principles and conditions relevant for the operationalization of a EPEF. Our proposal has several desirable features. It: a) offers better risk sharing opportunities, augmenting the resilience of businesses and EU economies; b) is need-based, thereby contributing to an effective use of resources; c) builds on conditions and credible controls, addressing adverse selection and moral hazard; d) is accessible to smaller and medium-sized firms, the backbone of Europe’s economy; e) applies Europewide uniform eligibility criteria, strengthening support among member states; f) is a scheme of limited duration, reducing (perceived) government interference in businesses; g) creates a template for a growth-oriented public policy, aligning public and private sector interests; and h) builds on the existing institutional infrastructure and requires minimal legislative adjustments

Coronavirus and Financial Stability 3.0: Try equity – risk sharing for companies, large and small

This policy letter adds to the current discussion on how to design a program of government assistance for firms hurt by the Coronavirus crisis. While not pretending to provide a cure-all proposal, the advocated scheme could help to bring funding to firms, even small firms, quickly, without increasing their leverage and default risk. The plan combines outright cash transfers to firms with a temporary, elevated corporate profit tax at the firm level as a form of conditional payback. The implied equity-like payment structure has positive risk-sharing features for firms, without impinging on ownership structures. The proposal has to be implemented at the pan-European level to strengthen Euro area resilience

BRAF mutation-specific promoter methylation of FOX genes in colorectal cancer

Background: Cancer-specific hypermethylation of (promoter) CpG islands is common during the tumorigenesis of colon cancer. Although associations between certain genetic aberrations, such as BRAF mutation and microsatellite instability, and the CpG island methylator phenotype (CIMP), have been found, the mechanisms by which these associations are established are still unclear. We studied genome-wide DNA methylation differences between