SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Pagels Joakim) ;mspu:(report)"

Sökning: WFRF:(Pagels Joakim) > Rapport

  • Resultat 1-10 av 11
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  •  
2.
  •  
3.
  • Madsen, Dan, et al. (författare)
  • Fire-Induced Radiological Integrated Assessment : Fire properties of selected materials and products
  • 2019
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Characterization of emissions from fires in a laboratory-controlled environment are presented in this report. The project is initiated by the CERN HSE Unit and is called FIRIA, Fire-Induced Radiological Integrated Assessment. The objective of FIRIA is to enhance the knowledge of aerosols emitted from fires in order to develop dispersion models of radiologically-activated material in case of fire. In this report, several normally occurring combustible products and materials are tested in a standardized setup for fire tests, the cone calorimeter. In the cone calorimeter, standardized fire tests according to ISO 5660-1:2015 have been performed as well as fire tests at reduced oxygen concentrations in a vitiated air chamber. As an additional setup, aerosol measurement equipment was coupled to the cone calorimeter ventilation duct to characterize the emitted aerosols as in the particle size distribution, mass yield and elemental analysis.The results show peak heat release rates for oil at 1100 kW/m2 at an incident heat flux of 50 kW/m2. Similar results for the plastic materials were 800 kW/m2. For cables and insulating plastic materials peak heat release rates at an incident heat flux of 50 kW/m2 were around 350 kW/m2. Significant for most of the cables was a heat release rate curve with two distinct peaks. This is proposed to be due to the outer combustible sheath burning first followed by the interior plastic insulating material of the cables burning. There could also be heat transfer effects and cracking of the material surface contributing to the two peaks. Nevertheless, for some cables a low incident heat flux led to only one peak indicating that only the sheath ignited. Time to ignition varied between the materials but was increased as the incident heat flux decreased. Reduced oxygen concentration in the vitiated air chamber also prolonged the ignition time as well as the heat release rates. The critical heat flux to ignite the cables was calculated to be just below 10 kW/m2. The oil and two cable types were tested in the vitiated air chamber to perform tests at reduced oxygen concentrations. These tests were performed to retrieve specific fire properties as well as specific emissions from such conditions. The tests were performed with a progressively lower oxygen concentrations until no ignition of the sample occurred. Results showed an ignition limit around 11-13 % oxygen at incident heat fluxes of 20-30 kW/m2. The tests in the vitiated air chamber is described in subreport FIRIA- Fire properties of selected materials and products in reduced oxygen conditions.
  •  
4.
  • Madsen, Dan, et al. (författare)
  • Fire-Induced Radiological Integrated Assessment : Fire properties of selected materials and products in reduce oxygen conditions
  • 2019
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Characterization of emissions from fires in a laboratory-controlled environment are presented in this report. The project is initiated by the CERN HSE Unit and is called FIRIA, Fire-Induced Radiological Integrated Assessment. The objective of FIRIA is to enhance the knowledge of aerosols emitted from fires in order to develop dispersion models of radiologically-activated material in case of fire. Standard cone calorimeter test were done on a variety of combustible products and materials and the results are presented in the report FD03 Fire-Induced Radiological Integrated Assessment - Fire properties of selected materials and products.In this report, a vitiated air chamber was used to test an oil and two cables at reduced oxygen concentrations that were also tested in the FD03 report. The vitiated air chamber was attached to the standard cone calorimeter and a reduction in oxygen concentration was achieved by mixing nitrogen with compressed air. This general setup has been referred to as the open controlled atmosphere cone calorimeter (CACC).This report contains fire properties of the oil and cables at different irradiances and oxygen concentrations. The properties included are the ignition time, mass loss rate, heat release rate per unit area (HRRPUA), carbon dioxide yield, carbon monoxide yield, heat of combustion, and extinction coefficient.The results from the reduced oxygen concentration tests were compared with the results from the FD03 report. Some observations from the comparison are: An increase in the ignition time when compared to tests done in the standard cone calorimeter occurred for the oil and both cables at the lowest oxygen concentration tested for each irradiance level. The average carbon monoxide yields remained relatively constant or increased with decreases in the oxygen concentration. A reduction in the oxygen concentration generally resulted in a decrease in the mass loss rate and heat release rate per unit area (HRRPUA). However, one of the cables, referred to as cable 4 (C04), did not have a reduction in the mass loss rate and HRRPUA when exposed to an irradiance of 50 kW/m2. Cable 8 (C08) also had a higher peak mass loss rate and peak HRRPUA when tested at an oxygen concentration of 17% though the mass loss rate and HRRPUA was lower than the standard cone calorimeter result for most of the test.The limiting oxygen concentration using nitrogen to dilute air was also estimated at an irradiance of 20 kW/m2 for the oil and 30 kW/m2 for the cables. The estimated limiting oxygen concentrations were: Oil: between 11% (no ignition) and 13% (ignition) at an irradiance of 20 kW/m2 Cable 4: between 12% (no ignition) and 14% (ignition) at an irradiance of 30 kW/m2 Cable 8: between 13% (no ignition) and 15% (ignition) at an irradiance of 30 kW/m2
  •  
5.
  • Malmborg, Vilhelm, et al. (författare)
  • Fire-induced radiological integrated assessment : aerosol characterization
  • 2019
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • This report on detailed aerosol characterization of fire smoke emissions is part of the Fire-Induced Radiological Integrated Assessment (FIRIA; CERN, Switzerland). In this study, carried out at Lund University, a number of materials were combusted in a cone calorimeter at varied heat fluxes. In a few experiments, the effect of reduced O2 content of supply air was investigated (vitiated conditions). The materials included electrical components, magnets, plastic components, oil and cables and were selected due to their high probability of experiencing ionizing radiation in the research facilities at CERN. The aerosol particle yield in the combustion emissions was determined in terms of number and mass emissions. In addition, the particle physical properties in terms of size distributions, the mass - mobility relationship, and the black carbon fraction of emitted particles was determined. Finally, the particle morphology was determined with transmission electron microscopy (TEM) and elemental composition of trace elements by ICP-MS. The total range of aerosol mass yields spanned from approximately 0.005 (g/g fuel) to 0.23 (g/g fuel). Electrical components and magnets were identified as the combustibles with highest mass yields. Mass yields for cables spanned from 0.005-0.09 g/g fuel. The emissions were highly dynamic, with rapid shifts in concentrations and the particle number size distribution as measured with a fast mobility spectrometer (DMS500). The number yields ranged from approximately 0.05*10^14 to 2*10^14 emitted particles per gram of fuel and was measured within the size range 5-1000 nm. The emissions could be parameterized for future modelling applications into nucleation mode particles (with geometric mean diameter that varied between 20-50 nm) and accumulation mode particles (with geometric mean diameter 100-230 nm). The aerosol mass yields were governed primarily by the concentration and size distribution of accumulation mode particles. Mass yields were determined from 1) Impactor measurements (Dekati Gravimetric Impactor) and 2) Simultaneous measurements of the electrical mobility size distribution (DMS500) and effective density distribution (DMA-APM). The general agreement between the two techniques was good (R2=0.93). Black carbon is indicative of refractory carbonaceous particles which form in fuel rich conditions of the hot flame environment and associated with the black color of soot (smoke). Black carbon yields were for most experiments similar to the derived mass yields. TEM images showed typical refractory black carbon aggregates at high BC fractions. The primary particle size was larger than for diesel exhaust. However, at reduced heat flux and during vitiated combustion (reduced O2 concentration), black carbon yields were sometimes much lower than the derived particle mass yields. TEM analysis for a sample with low BC fraction showed only very few particles and those that were found had distinctly different properties to the high BC fraction sample. We hypothesize that particles emitted under these conditions were dominated by low volatility organic matter formed in the pyrolysis of the materials. Such components were likely co-emitted with black carbon also in conventional experiments, although in minor mass fractions. Based on previous studies it can be hypothesized that H:C ratios are low for the cases with high BC fraction.
  •  
6.
  •  
7.
  •  
8.
  • Pagels, Joakim, et al. (författare)
  • Deposition of particle-attached radon progeny in the respiratory tract - an experimental study of children and adults in home environments
  • 1999
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • A method to study total deposition of aerosol attached radon progeny in children and adults have been validated and used in home environments. Two persons, one child and one adult are tested simultaneously, thus inhaling from the same aerosol and allowing for a direct comparison. The aim of the study was to increase the knowledge of the lung deposition and thereby the knowledge of the radiation dose from indoor radon. In the study 13 children (ages 4-13 years) and 11 adults were tested in their home environments (five dwellings with elevated radon levels 200 - 600 Bq/m3). Two different aerosols were used: the background aerosol particles when no strong indoor sources were present and the relatively small particles from normal candle burning (activity median diameters (AMD) roughly 200 and 50 nm respectively). An enhanced deposition was found for the children compared to the adults for the smaller particles (mean deposition 38 and 31%), while for the larger background particles no difference was found (31% deposition for both groups). Differences between the deposition of the different short lived radon daughters was found. This was infered to be explained as an ageing effect. In one of the dwellings measurements were performed to estimate hygroscopic growth of the particles upon inhalation. Growth factors between 1 and 4.5 was found. When comparing the results with a stochastic lung deposition model (hygroscopic growth taken into account) reasonable good agreement was found for the smaller particles (experiments 31% and model 26%), while for the larger background particles a roughly doubled deposition was found (experiments 31% and model 15%). A comparison of the deposition when breathing through mouth and nose has also been conducted. This part of the study with adults only was performed in a radon exposure chamber. Relatively large (AMD =500 nm) hydrophobic particles from flickering candle burning (black smoke) were used. Mean depositions of 11 and 17% were found when breathing through mouth and nose respectively. Good agreement was found when comparing with the stochastic model.
  •  
9.
  •  
10.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-10 av 11

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy