An approach for domino effect reduction based on optimal layouts

An approach to reduce the probability of producing a domino effect in process industry is developed in this work. It is assumed that optimal layouts should include appropriate analysis to reduce risk during the process design stage. The model developed for this approach combines the estimation of probability of damage due to overpressure, proposed by Mingguang and Juncheng (2008), and escalation threshold values defined by Cozzani, Gubinelli, and Salzano (2006). These equations are combined with other typical layout constraints as well as bounding the probability constraint, which has resulted in a highly non-linear MINLP problem. Solving a case study used by other authors provides evidence for reliability of the developed approach. In this way, layouts are designed to reduce the escalation probability yielding safe distributions.     

Key parametric analysis on designing an effective forced mitigation system for LNG spill emergency

Concerns over public safety and security of a potential liquefied natural gas (LNG) spill have promoted the need for continued improvement of safety measures for LNG facilities. The mitigation techniques have been recognized as one of the areas that require further investigation to determine the public safety impact of an LNG spill. Forced mitigation of LNG vapors using a water curtain system has been proven to be effective in reducing the vapor concentration by enhancing the dispersion. Currently, no engineering criteria for designing an effective water curtain system are available, mainly due to a lack of understanding of the complex droplet–vapor interaction. This work applies computational fluid dynamics (CFD) modeling to evaluate various key design parameters involved in the LNG forced mitigation using an upwards-oriented full-cone water spray. An LNG forced dispersion model based on a Eulerian–Lagrangian approach was applied to solve the physical interactions of the droplet–vapor system by taking into account the various effects of the droplets (discrete phase) on the air–vapor mixture (continuous phase). The effects of different droplet sizes, droplet temperatures, air entrainment rates, and installation configurations of water spray applications on LNG vapor behavior are investigated. Finally, the potential of applying CFD modeling in providing guidance for setting up the design criteria for an effective forced mitigation system as an integrated safety element for LNG facilities is discussed.     

Quantifying population declines based on presence‐only records for red‐list assessments

Accurate trend estimates are necessary for understanding which species are declining and which are most in need of conservation action. Imperfect species detection may result in unreliable trend estimates because this may lead to the overestimation of declines. Because many management decisions are based on population trend estimates, such biases could have severe consequences for conservation policy. We used an occupancy‐modeling framework to estimate detectability and calculate nationwide population trends for 14 Swiss amphibian species both accounting for and ignoring imperfect detection. Through the application of International Union for Conservation of Nature Red List criteria to the different trend estimates, we assessed whether ignoring imperfect detection could affect conservation policy. Imperfect detection occurred for all species and detection varied substantially among species, which led to the overestimation of population declines when detectability was ignored. Consequently, accounting for imperfect detection lowered the red‐list risk category for 5 of the 14 species assessed. We demonstrate that failing to consider species detectability can have serious consequences for species management and that occupancy modeling provides a flexible framework to account for observation bias and improve assessments of conservation status. A problem inherent to most historical records is that they contain presence‐only data from which only relative declines can be estimated. A move toward the routine recording of nonobservation and absence data is essential if conservation practitioners are to move beyond this toward accurate population trend estimation.     

Surface Consolidation of Pentelic Marble: Criteria for the selection of methods and materials - The Acropolis case (6 pp)

Goal and Scope In order to realize surface consolidation of Pentelic marble on the Acropolis monuments, we have collected the criteria that have to be fulfilled by the methods and materials without side effects on the marbles (and other stones). When the existing methods and materials did not satisfy the requirements (criteria), we invented new ones.Methods The criteria were collected from the literature, by thermodynamic and kinetic viewpoints, by laboratory experiments and in situ observations on monuments, both in Greece and in several countries in which the various methods and materials were applied. Concerning our method of ‘Inversion of sulfation’, performed by spraying a K2CO3 solution, its concentration and its temperature were controlled in order to have a total inversion (certified by liquid crystals) of gypsum back to CaCO3. For the new material of ours, ‘Reinforced Lime’, in order to eliminate the disadvantages of plain lime (low carbonation rate, low mechanical properties of CaCO3 formed, lack of carbonation in the bulk of lime), measurements of the rate of carbonation were performed in plain lime and in lime with a different CaCO3 concentration beforehand as well as in a different CO2 environments, using DTG and XRD to measure the rate of carbonation. The detachment (kg/cm2) of marble specimens stuck by lime in each case was also measured. A microscope was also used to measure the dimensions of the grain in each case as well as ammonium citrate and thymolphthalein to certify the depth of carbonation in each case. Part of the work was communicated in an international congress.Results A table with the criteria of the selection of the methods and materials for the consolidation of Pentelic marble surfaces (and other stones) was established. None of the employed methods and materials fulfilled the criteria. Only the ‘Inversion of gypsum ‘ and the ‘Reinforced Lime’ were adopted and applied to the Acropolis monuments and to other monuments in Greece and in several other countries.Recommendation and Outlook All criteria must be used for the selection of methods and materials for the consolidation of the monument surfaces. This is why we have already studied with the same procedures, methods and materials for restoration, surface cleaning and protection.     

Flammability of heat transfer fluid aerosols produced by electrospray measured by laser diffraction analysis

Accidental release of pressurized high flash point heat transfer fluids can result in fire and explosion hazard scenarios in the process industry. An experimental investigation on ignition of aerosols of a heat transfer fluid is carried out, and characterization of aerosol and its ignition process by non-intrusive laser diffraction technique is reported. Propagation speed of the aerosol combustion flame front as analyzed from the laser diffraction measurement agrees with high-speed visual camera observation. Flammability of the aerosol, which is based on the chances of the global flame appearance in the aerosol, is mainly controlled by aerosol droplet size and the droplet volume concentration.     

Emissions of biogenic VOC from forest ecosystems in central Europe: Estimation and comparison with anthropogenic emission inventory

This paper describes a method of estimating emission fluxes of biogenic volatile organic compounds (BVOCs) based on the approach proposed by Guenther et al. (1995) and the high-resolution Corine land-cover 2000 database (1 × 1 km resolution). The computed emission fluxes for the Czech Republic (selected for analysis as being representative of a heavily cultivated, central European country) are compared with anthropogenic emissions, both for the entire country and for individual administrative regions. In some regions, BVOC emissions are as high as anthropogenic emissions; however, in most regions the BVOC emissions are approximately 50% of the anthropogenic emissions. The yearly course of BVOC emissions (represented by monoterpenes and isoprene) is presented, along with the spatial distribution of annual mean values. Differences in emission distributions during winter (January) and summer (June) are also considered.     

Confined placental mosaicism for trisomy 14 and maternal uniparental disomy in association with elevated second trimester maternal serum human chorionic gonadotrophin and third trimester fetal growth restriction

A case of confined placental mosaicism (CPM) and maternal uniparental isodisomy 14 identified after placental karyotype revealed trisomy 14 in a newborn with intrauterine growth restriction (IUGR) and minor dysmorphic features is reported. During the second trimester of the pregnancy, multiple marker screening revealed an increased risk for Down syndrome of >1 in 10. The maternal serum human chorionic gonadotrophin (MShCG) was markedly elevated at 4.19 MoM. Amniocentesis revealed a normal 46,XX karyotype. Fetal growth restriction has been associated with elevated MShCG and placental aneuploidy with CPM for chromosomes 2, 7, 9 and 16. The present case of CPM for chromosome 14 was also associated with fetal growth restriction and elevated second trimester MShCG, suggesting a common link. Further studies need to be done to determine if indeed elevation of second trimester MShCG is associated with increased risk of CPM. The present case again demonstrates the need to perform placental karyotype in unexplained fetal growth restriction. Copyright © 2001 John Wiley & Sons, Ltd.     

From the outside in: The negative spillover effects of boundary spanners' relations with members of other organizations

Contrary to much boundary spanning research, we examined the negative consequences of boundary spanning contact in multi‐organizational contexts. Results from a sample of 833 Dutch peacekeepers show that employees' boundary spanning contact with members of other organizations was associated with reports of negative relationships with external parties (e.g., work‐specific problems, culture‐specific problems). These negative relationships also had a spillover effect such that they mediated the effect of boundary spanning contact on boundary spanners' negative attitudes toward their own jobs and organization (e.g., job attractiveness and confidence in the organization). Copyright © 2010 John Wiley & Sons, Ltd.