Retrospective Review of Treponema pallidum PCR and Serology Results: Are Both Tests Necessary?

Science.gov (United States)

Brischetto, Anna; Gassiep, Ian; Whiley, David; Norton, Robert

2018-05-01

There has been a resurgence of syphilis diagnoses in Australia. We investigated whether our Treponema pallidum PCR test provides any additional diagnostic information over syphilis serology (chemiluminescence immunoassay [CMIA], Treponema pallidum particle agglutination [TPPA] assay, and the rapid plasma reagin [RPR] flocculation test). A retrospective audit of all T. pallidum PCR requests that came through our laboratory from January 2010 to June 2017 was conducted; data collected included age, gender, site of swab, and results from T. pallidum PCR, syphilis serology, and herpes simplex virus 1 (HSV-1) and HSV-2 PCRs. A total of 441 T. pallidum PCR tests were performed; on average, 3 T. pallidum PCRs per month were requested in 2011, and this rate increased to 17.2 requests per month in 2017. A total of 323 patients had both T. pallidum PCR and syphilis serology performed, with 67% of swabs taken from the genitals. T. pallidum PCR gave positive results for 61/323 (19%) patients; of these 61 patients, 59 (97%) also had positive syphilis serology results ( T. pallidum PCR sensitivity, 68%; specificity, 99%; positive predictive value, 97%; negative predictive value, 89%). Syphilis serology was positive for 91/323 patients (28%); of these 91 patients, 61 (66%) were also T. pallidum PCR positive (syphilis serology sensitivity, 97%; specificity, 88%; positive predictive value, 60%; negative predictive value, 99%). The Cohen's kappa value was 0.74, indicating substantial agreement between the two tests. Our results show that most patients with positive T. pallidum PCR results also had positive syphilis serology. Therefore, T. pallidum PCR adds little clinical value over serology for the diagnosis of syphilis in certain clinical settings. Copyright © 2018 American Society for Microbiology.

Development of a code for description of sodium spray and pool fires. Pt. 1

International Nuclear Information System (INIS)

Alexas, A.

1979-09-01

In the scope of the development of a code to describe both, sodium pool- and spray fires, the well-known codes SOFIRE II and NABRAND have been compared. Regarding the program technique of both codes, the NABRAND-code seems to be the better one, though it includes some conservatisms in the modelling and in the transport coefficients used. For a realistic estimation of the consequences of large sodium fires in an LMFBR, an elimination of these conservatisms is necessary. After that it must be investigated if a combination of the modificated version of the NABRAND-code and of a spray fire-code (for example the code SPRAY) is efficient. (orig.) [de

Multiple primary syphilis on the lip, nipple-areola and penis: An immunohistochemical examination of Treponema pallidum localization using an anti-T. pallidum antibody.

Science.gov (United States)

Fukuda, Hidetsugu; Takahashi, Misaki; Kato, Keiichi; Oharaseki, Toshiaki; Mukai, Hideki

2015-05-01

Primary syphilis caused by Treponema pallidum usually develops after sexual contact as an initial solitary sclerosis or hard chancre in the genital region. We describe a case of primary syphilis at three sites in genital and extragenital regions of a man who had sex with men. A 29-year-old man visited our hospital for skin lesions on his lower lip, nipple-areola and penis. A positive syphilis serological test for rapid plasma reagin had a titer of 1:16; the patient also tested positive for specific antibodies against T. pallidum, with a cut-off index of 39.0. Histopathological examination of a nipple-areola biopsy specimen revealed a thickened epidermis and dense infiltration of inflammatory cells extending from the upper dermal layers to the deep dermis. The inflammatory cells were composed of abundant lymphocytes, plasma cells, histiocytes and neutrophils. Immunohistochemical staining for T. pallidum using an anti-T. pallidum antibody showed numerous spirochetes in the lower portion of the epidermis, scattered inside inflammatory cell infiltrate and perivascular sites throughout the dermis. Based on these findings, the patient was diagnosed with primary syphilis. Treatment with oral amoxicillin hydrate was started. Five days after starting treatment, a diffuse maculopapular rash (syphilitic roseola) occurred on his trunk and extremities. Perivascular cuffing due to T. pallidum was present throughout the dermis in the biopsy specimen of a localized lesion of primary syphilis. Moreover, syphilitic roseola, which indicates generalized dissemination of T. pallidum, developed during the course of treatment for primary syphilis. Therefore, we considered perivascular cuffing to be indicative of the dissemination phase. © 2015 Japanese Dermatological Association.

Validation analysis of pool fire experiment (Run-F7) using SPHINCS code

International Nuclear Information System (INIS)

Yamaguchi, Akira; Tajima, Yuji

1998-04-01

SPHINCS (Sodium Fire Phenomenology IN multi-Cell System) code has been developed for the safety analysis of sodium fire accident in a Fast Breeder Reactor. The main features of the SPHINCS code with respect to the sodium pool fire phenomena are multi-dimensional modeling of the thermal behavior in sodium pool and steel liner, modeling of the extension of sodium pool area based on the sodium mass conservation, and equilibrium model for the chemical reaction of pool fire on the flame sheet at the surface of sodium pool during. Therefore, the SPHINCS code is capable of temperature evaluation of the steel liner in detail during the small and/or medium scale sodium leakage accidents. In this study, Run-F7 experiment in which the sodium leakage rate is 11.8 kg/hour has been analyzed. In the experiment the diameter of the sodium pool is approximately 60 cm and the maximum steel liner temperature was 616 degree C. The analytical results tell us the agreement between the SPHINCS analysis and the experiment is excellent with respect to the time history and spatial distribution of the liner temperature, sodium pool extension behavior, as well as atmosphere gas temperature. It is concluded that the pool fire modeling of the SPHINCS code has been validated for this experiment. The SPHINCS code is currently applicable to the sodium pool fire phenomena and the temperature evaluation of the steel liner. The experiment series are continued to check some parameters, i.e., sodium leakage rate and the height of sodium leakage. Thus, the author will analyze the subsequent experiments to check the influence of the parameters and applies SPHINCS to the sodium fire consequence analysis of fast reactor. (author)

Há 100 anos, a descoberta do Treponema pallidum A hundred years ago, the discovery of Treponema pallidum

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Elemir Macedo de Souza

2005-10-01

Full Text Available A descoberta do Treponema pallidum por Schaudinn & Hoffmann em 3 de março de 1905 foi influenciada pela comunicação de Siegel, sobre a descoberta do agente etiológico da sífilis. Encarada com ceticismo, a comunicação acarretou novas investigações, conduzidas pelo zoologista Schaudinn e pelo dermatologista Hoffmann -primeiros observadores do agente da sífilis, denominado Spirochaeta pallida. A descoberta foi o passo inicial para o desenvolvimento dos procedimentos diagnósticos e terapêuticos nos anos subseqüentes.The discovery of Treponema pallidum by Schaudinn & Hoffmann, on March 3rd 1905, was influenced by Siegels' communication on the finding of the etiological agent of syphilis. John Siegel, working at the Institut of Zoology, University of Berlin, claimed to have found a flagellate protozoon in syphilitic lesions. Because of the skepticism it was received with, this communcation yielded further investigation, conducted by zoologist Schaudinn and dermatologist Hoffmann. They were the first investigators to find the etiological agent of syphilis, described under the name of Spirochaeta pallida. The discovery of Treponema pallidum on March 3rd 1905 was the first step towards the development of diagnostic and therapeutic procedures in subsequent years.

Computing the effects of a contained sodium sheet fire: The 'FEUNA' code

International Nuclear Information System (INIS)

Duverger De Cuy, G.

1979-01-01

FEUNA is a computer code developed to calculate the thermodynamic effects of a sodium fire in a ventilated or unventilated containment volume. Developed jointly by the CEA/DSN and Novatome, the FEUNA code involves two oxide formation reactions, aerosol generation and deposits, heat transfer by convection, conduction and radiation, gas inflow and outflow through the ventilation system and the relief valves. The code was validated by comparing calculated values with the results of an actual sodium fire in a 400m 3 caisson. (author)

Computing the effects of a contained sodium sheet fire: The 'FEUNA' code

Energy Technology Data Exchange (ETDEWEB)

Duverger De Cuy, G [DSN/SESTR, Centre de Cadarache, Saint-Paul-lez-Durance (France)

1979-03-01

FEUNA is a computer code developed to calculate the thermodynamic effects of a sodium fire in a ventilated or unventilated containment volume. Developed jointly by the CEA/DSN and Novatome, the FEUNA code involves two oxide formation reactions, aerosol generation and deposits, heat transfer by convection, conduction and radiation, gas inflow and outflow through the ventilation system and the relief valves. The code was validated by comparing calculated values with the results of an actual sodium fire in a 400m{sup 3} caisson. (author)

Calculation code evaluating the confinement of a nuclear facility in case of fires

International Nuclear Information System (INIS)

Laborde, J.C.; Prevost, C.; Vendel, J.

1995-01-01

Accident events involving fire are quite frequent and could have a severe effect on the safety of nuclear facilities. As confinement must be maintained, the ventilation and filtration systems have to be designed to limit radioactive release to the environment. To determine and analyse the consequences of a fire on the contamination confinement, IPSN, COGEMA and SGN are participating in development of a calculation code based on introduction, in the SIMEVENT ventilation code, of various models associated to fire risk and mass transfer in the ventilation networks. This calculation code results from the coupling of the SIMEVENT code with several models describing the temperature in a room resulting of a fire, the temperatures along the ventilation ducts, the contamination transfers through out the ventilation equipments (ducts, dampers, valves, air cleaning systems) and the High Efficiency Particulate Air (HEPA) filters clogging. The paper proposed presents the current level of progress in development of this calculation code. It describes, in particular, the empirical model used for the clogging of HEPA filters by the aerosols derived from the combustion of standard materials used in the nuclear industry. It describes, also, the specific models used to take into account the mass transfers and resulting from the basic mechanisms of aerosols physics. In addition, an assessment of this code is given using the example of a simple laboratory installation

Calculation code evaluating the confinement of a nuclear facility in case of fires

Energy Technology Data Exchange (ETDEWEB)

Laborde, J.C.; Prevost, C.; Vendel, J. [and others

1995-02-01

Accident events involving fire are quite frequent and could have a severe effect on the safety of nuclear facilities. As confinement must be maintained, the ventilation and filtration systems have to be designed to limit radioactive release to the environment. To determine and analyse the consequences of a fire on the contamination confinement, IPSN, COGEMA and SGN are participating in development of a calculation code based on introduction, in the SIMEVENT ventilation code, of various models associated to fire risk and mass transfer in the ventilation networks. This calculation code results from the coupling of the SIMEVENT code with several models describing the temperature in a room resulting of a fire, the temperatures along the ventilation ducts, the contamination transfers through out the ventilation equipments (ducts, dampers, valves, air cleaning systems) and the High Efficiency Particulate Air (HEPA) filters clogging. The paper proposed presents the current level of progress in development of this calculation code. It describes, in particular, the empirical model used for the clogging of HEPA filters by the aerosols derived from the combustion of standard materials used in the nuclear industry. It describes, also, the specific models used to take into account the mass transfers and resulting from the basic mechanisms of aerosols physics. In addition, an assessment of this code is given using the example of a simple laboratory installation.

Detección de Treponema pallidum subespecie pallidum para el diagnóstico de sífilis congénita mediante reacción en cadena de la polimerasa anidada.

Science.gov (United States)

Pinilla, Gladys; Campos, Lesly; Durán, Andrea; Navarrete, Jeannette; Muñoz, Liliana

2018-03-15

Introducción. La sífilis es una enfermedad producida por Treponema pallidum subespecie pallidum cuya incidencia mundial es de 12 millones de casos por año, aproximadamente; de estos, más de dos millones se presentan en mujeres gestantes, siendo la sífilis congénita la complicación más grave de esta infección en el embarazo.Objetivo. Detectar la presencia de T. pallidum subespecie pallidum en muestras clínicas para el diagnóstico de sífilis congénita mediante reacción en cadena de la polimerasa (PCR) anidada y determinar su concordancia con las pruebas serológicas.Materiales y métodos. Mediante PCR convencional y anidada, se amplificaron tres genes diana (polA, 16S ADNr y TpN47) y se confirmaron los productos de amplificación de los genes TpN47 y polA por secuenciación. Las pruebas serológicas empleadas fueron la VDRL (Venereal Disease Research Laboratory), la de reagina plasmática rápida (Rapid Plasma Reagin, RPR) y la de aglutinación de partículas para Treponema pallidum (Treponema pallidum Particle Agglutination Assay, TPPA).Resultados. La sensibilidad para la PCR convencional fue de 52 pg y, para la PCR anidada, de 0,52 pg. La especificidad con los iniciadores TpN47 y polA fue de 100 %; los resultados de la secuenciación mostraron una identidad de 97 % con T. pallidum. En 70 % de las muestras, los resultados de las pruebas serológicas y la PCR anidada concordaron.Conclusión. El gen TpN47 resultó ser el mejor blanco molecular para la identificación de T. pallidum. La PCR anidada se presenta como una alternativa de diagnóstico molecular promisoria para el diagnóstico de sífilis congénita.

Sodium pool fire model for CONACS code

International Nuclear Information System (INIS)

Yung, S.C.

1982-01-01

The modeling of sodium pool fires constitutes an important ingredient in conducting LMFBR accident analysis. Such modeling capability has recently come under scrutiny at Westinghouse Hanford Company (WHC) within the context of developing CONACS, the Containment Analysis Code System. One of the efforts in the CONACS program is to model various combustion processes anticipated to occur during postulated accident paths. This effort includes the selection or modification of an existing model and development of a new model if it clearly contributes to the program purpose. As part of this effort, a new sodium pool fire model has been developed that is directed at removing some of the deficiencies in the existing models, such as SOFIRE-II and FEUNA

Detection of Treponema pallidum subsp. pallidum from Skin Lesions, Serum, and Cerebrospinal Fluid in an Infant with Congenital Syphilis after Clindamycin Treatment of the Mother during Pregnancy▿

Science.gov (United States)

Woznicová, Vladana; Šmajs, David; Wechsler, Dan; Matějková, Petra; Flasarová, Magdalena

2007-01-01

We report here a case of congenital syphilis in a newborn after clindamycin treatment in pregnancy. Using PCR detection of tmpC (TP0319) and DNA sequencing of the genes TP0136 and TP0548, DNA sequences identical to Treponema pallidum subsp. pallidum strain SS14 were detected in the infant's skin lesions, serum, and cerebrospinal fluid. PMID:17151205

COMPBRN III: a computer code for modeling compartment fires

International Nuclear Information System (INIS)

Ho, V.; Siu, N.; Apostolakis, G.; Flanagan, G.F.

1986-07-01

The computer code COMPBRN III deterministically models the behavior of compartment fires. This code is an improvement of the original COMPBRN codes. It employs a different air entrainment model and numerical scheme to estimate properties of the ceiling hot gas layer model. Moreover, COMPBRN III incorporates a number of improvements in shape factor calculations and error checking, which distinguish it from the COMPBRN II code. This report presents the ceiling hot gas layer model employed by COMPBRN III as well as several other modifications. Information necessary to run COMPBRN III, including descriptions of required input and resulting output, are also presented. Simulation of experiments and a sample problem are included to demonstrate the usage of the code. 37 figs., 46 refs

Enhanced Molecular Typing of Treponema pallidum subspecies pallidum Strains From 4 Italian Hospitals Shows Geographical Differences in Strain Type Heterogeneity, Widespread Resistance to Macrolides, and Lack of Mutations Associated With Doxycycline Resistance.

Science.gov (United States)

Giacani, Lorenzo; Ciccarese, Giulia; Puga-Salazar, Christian; Dal Conte, Ivano; Colli, Laura; Cusini, Marco; Ramoni, Stefano; Delmonte, Sergio; DʼAntuono, Antonietta; Gaspari, Valeria; Drago, Francesco

2018-04-01

Although syphilis rates have been relatively high in Italy for more than 15 years, no data on the molecular types of Treponema pallidum subspecies pallidum circulating in this country are yet available. Likewise, no data on how widespread is resistance to macrolide or tetracycline antibiotics in these strains exist. Such data would, however, promote comprehensive studies on the molecular epidemiology of syphilis infections in Italy and inform future interventions aiming at syphilis control in this and other European countries. Swabs from oral, genital, cutaneous, or anal lesions were obtained from 60 syphilis patients attending dermatology clinics in Milan, Turin, Genoa, and Bologna. Molecular typing of T. pallidum DNA was performed to provide a snapshot of the genetic diversity of strains circulating in Northern Italy. Samples were also screened for mutations conferring resistance to macrolides and tetracyclines. T. pallidum DNA was detected in 88.3% (53/60) of the specimens analyzed. Complete and partial T. pallidum typing data were obtained for 77.3% (41/53) and 15.0% (8/53) of samples, respectively, whereas 4 samples could not be typed despite T. pallidum DNA being detected. The highest strain type heterogeneity was seen in samples from Bologna and Milan, followed by Genoa. Minimal diversity was detected in samples from Turin, despite the highest number of typeable samples collected there. Resistance to macrolides was detected in 94.3% (50/53) of the strains, but no known mutations associated with tetracycline resistance were found. Genetic diversity among T. pallidum strains circulating in Northern Italy varies significantly among geographical areas regardless of physical distance. Resistance to macrolides is widespread.

76 FR 22381 - National Fire Codes: Request for Comments on NFPA Technical Committee Reports

Science.gov (United States)

2011-04-21

... Stored Electrical P Energy Emergency and Standby Power Systems. NFPA 291 Recommended Practice for Fire P.... NFPA 400 Hazardous Materials Code....... P NFPA 402 Guide for Aircraft Rescue and P Fire-Fighting... Installation, P Maintenance, and Use of Emergency Services Communications Systems. NFPA 1500 Standard on Fire...

A computer code SPHINCS for sodium fire safety evaluation

International Nuclear Information System (INIS)

Yamaguchi, Akira

2000-01-01

A computer code SPHINCS solves coupled phenomena of thermal-hydraulics and sodium fire based on a multi-zone model. It deals with arbitrary number of rooms each of which is connected mutually by doorway and penetrations. With regard to the combustion phenomena, flame sheet model and liquid droplet combustion model are used for pool and spray fire, respectively, with the chemical equilibrium model using Gibbs free energy minimization method. The chemical reaction and mass and heat transfer are solved interactively. A specific feature of SPHINCS is detailed representation of thermal-hydraulics of a sodium pool and a steel liner, which is placed on the floor to prevent sodium-concrete contact. The author analyzed a series of pool combustion experiments, in which gas and liner temperatures are measured in detail. It has been found that good agreement is obtained and the SPHINCS has been validated with regard to the pool combustion phenomena. Further research needs are identified for the pool spreading modeling considering thermal deformation of liner and measurement of pool fluidity property of a mixture of liquid sodium and reaction products. SPHINCS code is to be used mainly in the safety evaluation of the consequence of sodium fire accident of liquid metal cooled fast reactor. (author)

76 FR 70414 - National Fire Protection Association (NFPA) Proposes To Revise Codes and Standards

Science.gov (United States)

2011-11-14

... Commercial Cooking Operations. NFPA 99--2012 Health Care Facilities Code 6/22/2012 NFPA 99B--2010 Standard... Explosion Investigations..... 1/4/2012 NFPA 1005--2007 Standard for Professional Qualifications for 1/4/2012 Marine Fire Fighting for Land-Based Fire Fighters. NFPA 1021--2009 Standard for Fire Officer Professional...

Failure of PCR to Detect Treponema pallidum ssp. pertenue DNA in Blood in Latent Yaws.

Directory of Open Access Journals (Sweden)

Michael Marks

Full Text Available Yaws, caused by Treponema pallidum ssp. pertenue, is a neglected tropical disease closely related to venereal syphilis and is targeted for eradication by 2020. Latent yaws represents a diagnostic challenge, and current tools cannot adequately distinguish between individuals with true latent infection and individuals who are serofast following successful treatment. PCR on blood has previously been shown to detect T. pallidum DNA in patients with syphilis, suggesting that this approach may be of value in yaws. We performed real-time PCR for Treponema pallidum ssp. pertenue on blood samples from 140 children with positive T. pallidum Particle Agglutination (TPPA and Rapid Plasma Reagin (RPR tests and 7 controls (negative serology, all collected as part of a prospective study of yaws in the Solomon Islands. All samples were also tested by a nested PCR for T. pallidum. 12 patients had clinical evidence of active yaws whilst 128 were considered to have latent yaws. 43 children had high titre rapid plasma reagins (RPRs of ≥1:32. PCR testing with both assays gave negative results in all cases. It is possible that the failure to detect T. pallidum ssp. pertenue in blood reflects lower loads of organism in latent yaws compared to those in latent infection with T. pallidum ssp. pertenue, and/or a lower propensity for haematogenous dissemination in yaws than in syphilis. As the goal of the yaws control programme is eradication, a tool that can differentiate true latent infection from individuals who are serofast would be of value; however, PCR of blood is not that tool.

Failure of PCR to Detect Treponema pallidum ssp. pertenue DNA in Blood in Latent Yaws.

Science.gov (United States)

Marks, Michael; Katz, Samantha; Chi, Kai-Hua; Vahi, Ventis; Sun, Yongcheng; Mabey, David C; Solomon, Anthony W; Chen, Cheng Y; Pillay, Allan

2015-01-01

Yaws, caused by Treponema pallidum ssp. pertenue, is a neglected tropical disease closely related to venereal syphilis and is targeted for eradication by 2020. Latent yaws represents a diagnostic challenge, and current tools cannot adequately distinguish between individuals with true latent infection and individuals who are serofast following successful treatment. PCR on blood has previously been shown to detect T. pallidum DNA in patients with syphilis, suggesting that this approach may be of value in yaws. We performed real-time PCR for Treponema pallidum ssp. pertenue on blood samples from 140 children with positive T. pallidum Particle Agglutination (TPPA) and Rapid Plasma Reagin (RPR) tests and 7 controls (negative serology), all collected as part of a prospective study of yaws in the Solomon Islands. All samples were also tested by a nested PCR for T. pallidum. 12 patients had clinical evidence of active yaws whilst 128 were considered to have latent yaws. 43 children had high titre rapid plasma reagins (RPRs) of ≥1:32. PCR testing with both assays gave negative results in all cases. It is possible that the failure to detect T. pallidum ssp. pertenue in blood reflects lower loads of organism in latent yaws compared to those in latent infection with T. pallidum ssp. pertenue, and/or a lower propensity for haematogenous dissemination in yaws than in syphilis. As the goal of the yaws control programme is eradication, a tool that can differentiate true latent infection from individuals who are serofast would be of value; however, PCR of blood is not that tool.

41 CFR 102-80.85 - Are Federally owned and leased buildings exempt from State and local code requirements in fire...

Science.gov (United States)

2010-07-01

... leased buildings exempt from State and local code requirements in fire protection? 102-80.85 Section 102... Fire Prevention State and Local Codes § 102-80.85 Are Federally owned and leased buildings exempt from State and local code requirements in fire protection? Federally owned buildings are generally exempt...

The FIRAC code - its applicability and boundary conditions for fire accident analysis in a reprocessing plant

International Nuclear Information System (INIS)

Roewekamp, M.

1991-01-01

After a short description of the modelling capabilities and the implementation of the computer code the possible applications of FIRAC are demonstrated by means of two test-examples. The so gained experiences with respect to the variation of different parameters, convergency criteria, etc. can be used for the simulation of a fire accident in the storage area for unconditioned combustible low active waste (LAW) of the planned reprocessing plant at Wackersdorf. The code is prepared for calculating direct effects (of the fire) in the fire room as well as particularly effects on adjacent rooms and ventilation systems. Source terms for the release of radioactive particles outside a building can also be investigated. The temperature and pressure curves for the fire room as well as for other areas in the facility show that no damages caused by temperature effects are expected for the considered fire of low active waste. As a result of the calculated mass and volumetric flows radioactive aerosole particles could be transported into normally non-active areas. The FIRAC code renders the possibility of a more detailed analysis of those parameters relevant for fire accidents and by this means completes the so far phenomenological procedure of the fire hazard analysis in nuclear facilities. (orig.) [de

SERODYNAMICS OF TREPONEMA PALLIDUM IN SERUM OF ...

African Journals Online (AJOL)

drclement

ABSTRACT. Treponema pallidum, the causative agent of syphilis has been a public health challenge for centuries. Sexually transmitted infections (STIs) and HIV/AIDS are widespread in the developing countries, and constitute a major public health problem in Sub-. Saharan Africa. Information regarding the prevalence of ...

Neelaredoxin, an iron-binding protein from the syphilis spirochete, Treponema pallidum, is a superoxide reductase.

Science.gov (United States)

Jovanović, T; Ascenso, C; Hazlett, K R; Sikkink, R; Krebs, C; Litwiller, R; Benson, L M; Moura, I; Moura, J J; Radolf, J D; Huynh, B H; Naylor, S; Rusnak, F

2000-09-15

Treponema pallidum, the causative agent of venereal syphilis, is a microaerophilic obligate pathogen of humans. As it disseminates hematogenously and invades a wide range of tissues, T. pallidum presumably must tolerate substantial oxidative stress. Analysis of the T. pallidum genome indicates that the syphilis spirochete lacks most of the iron-binding proteins present in many other bacterial pathogens, including the oxidative defense enzymes superoxide dismutase, catalase, and peroxidase, but does possess an orthologue (TP0823) for neelaredoxin, an enzyme of hyperthermophilic and sulfate-reducing anaerobes shown to possess superoxide reductase activity. To analyze the potential role of neelaredoxin in treponemal oxidative defense, we examined the biochemical, spectroscopic, and antioxidant properties of recombinant T. pallidum neelaredoxin. Neelaredoxin was shown to be expressed in T. pallidum by reverse transcriptase-polymerase chain reaction and Western blot analysis. Recombinant neelaredoxin is a 26-kDa alpha(2) homodimer containing, on average, 0.7 iron atoms/subunit. Mössbauer and EPR analysis of the purified protein indicates that the iron atom exists as a mononuclear center in a mixture of high spin ferrous and ferric oxidation states. The fully oxidized form, obtained by the addition of K(3)(Fe(CN)(6)), exhibits an optical spectrum with absorbances at 280, 320, and 656 nm; the last feature is responsible for the protein's blue color, which disappears upon ascorbate reduction. The fully oxidized protein has a A(280)/A(656) ratio of 10.3. Enzymatic studies revealed that T. pallidum neelaredoxin is able to catalyze a redox equilibrium between superoxide and hydrogen peroxide, a result consistent with it being a superoxide reductase. This finding, the first description of a T. pallidum iron-binding protein, indicates that the syphilis spirochete copes with oxidative stress via a primitive mechanism, which, thus far, has not been described in pathogenic

Performance Assessment and analysis of national building codes with fire safety in all wards of a hospital

Directory of Open Access Journals (Sweden)

M. Mahdinia

2009-04-01

Full Text Available Background and aimsAIDS as a re-emergent disease and Viral hepatitis (B and C as one of thBackground and objective: Fire safety is an important problem in hospitals. Movement less, lack of awareness and special situation of residents are the reasons of this subject. In more countries such as Iran, fire protection regulations have compiled within the framework of national building codes. Current building codes don't create sufficient safety for patient in the hospitals in different situations and more of the advanced countries in the world effort to establish building code, base  on performance. This study to be accomplished with this goal that determination of fire risk level in the wards of a hospital and survey the efficiency of the national building codes. Methodsfire risk assesses is done, using "engineering fire risk assessment method" with the checklist for Data gathering. In this manner, risk calculate in all compartments and in the next  stage for survey the effect of building codes, with this supposition that all compartment is  conforming to building code requirement, risk level calculate in two situation.Resultsthe results of present study reveals that, risk level in all wards is more than one and even though risk less than one is acceptable, consequently minimum of safely situations didn't  produce in most wards. The results show the national building code in the different conditions  don't have appropriate efficient for creation of suitable safety. Conclusionin order to access to a fire safety design with sufficient efficiency, suitable selection is use of risk assessment based on, design methods.

Sodium spray and jet fire model development within the CONTAIN-LMR code

International Nuclear Information System (INIS)

Scholtyssek, W.

1993-01-01

An assessment was made of the sodium spray fire model implemented in the CONTAIN code. The original droplet burn model, which was based on the NACOM code, was improved in several aspects, especially concerning evaluation of the droplet burning rate, reaction chemistry and heat balance, spray geometry and droplet motion, and consistency with CONTAIN standards of gas property evaluation. An additional droplet burning model based on a proposal by Krolikowski was made available to include the effect of the chemical equilibrium conditions at the flame temperature. The models were validated against single-droplet burn experiments as well as spray and jet fire experiments. Reasonable agreement was found between the two burn models and experimental data. When the gas temperature in the burning compartment reaches high values, the Krolikowski model seems to be preferable. Critical parameters for spray fire evaluation were found to be the spray characterization, especially the droplet size, which largely determines the burning efficiency, and heat transfer conditions at the interface between the atmosphere and structures, which controls the thermal hydraulic behavior in the burn compartment

Computer simulations of a generic truck cask in a regulatory fire using the Container Analysis Fire Environment (CAFE) code

International Nuclear Information System (INIS)

Ju, H.; Greiner, M.; Suo-Anttila, A.

2002-01-01

The Container Analysis Fire Environment (CAFE) computer code is designed to predict accurately convection and radiation heat transfer to a thermally massive object engulfed in a large pool fire. It is well suited for design and risk analyses of spent nuclear fuel transport systems. CAFE employs computational fluid dynamics and several fire and radiation models. These models must be benchmarked using experimental results. In this paper, a set of wind velocity conditions are determined which allow CAFE accurately to reproduce recent heat transfer measurements for a thick walled calorimeter in a ST-1 regulatory pool fire. CAFE is then used to predict the response of an intack (thin walled) generic legal weight truck cask. The maximum temperatures reached by internal components are within safe limits. A simple 800 deg. C, grey-radiation fire model gives maximum component temperatures that are somewhat below those predicted by CAFE. (author)

Validation study of computer code SPHINCS for sodium fire safety evaluation of fast reactor

International Nuclear Information System (INIS)

Yamaguchi, Akira; Tajima, Yuji

2003-01-01

A computer code SPHINCS solves coupled phenomena of thermal hydraulics and sodium fire based on a multi-zone model. It deals with an arbitrary number of rooms, each of which is connected mutually by doorways and penetrations. With regard to the combustion phenomena, a flame sheet model and a liquid droplet combustion model are used for pool and spray fires, respectively, with the chemical equilibrium model based on the Gibbs free energy minimization method. The chemical reaction and mass and heat transfer are solved interactively. A specific feature of SPHINCS is detailed representation of thermalhydraulics of a sodium pool and a steel liner, which is placed on the floor to prevent sodium-concrete contact. The authors analyzed a series of pool combustion experiments, in which gas and liner temperatures are measured in detail. It has been found that good agreement is obtained and the SPHINCS code has been validated with regard to pool combustion phenomena. Further research needs are identified for pool spreading modeling considering thermal deformation of steel liner and measurement of pool fluidity property as a mixture of liquid sodium and reaction products. The SPHINCS code is to be used mainly in the safety evaluation of the consequence of a sodium fire accident in a liquid metal cooled fast reactor as well as fire safety analysis in general

Verification of fire and explosion accident analysis codes (facility design and preliminary results)

International Nuclear Information System (INIS)

Gregory, W.S.; Nichols, B.D.; Talbott, D.V.; Smith, P.R.; Fenton, D.L.

1985-01-01

For several years, the US Nuclear Regulatory Commission has sponsored the development of methods for improving capabilities to analyze the effects of postulated accidents in nuclear facilities; the accidents of interest are those that could occur during nuclear materials handling. At the Los Alamos National Laboratory, this program has resulted in three computer codes: FIRAC, EXPAC, and TORAC. These codes are designed to predict the effects of fires, explosions, and tornadoes in nuclear facilities. Particular emphasis is placed on the movement of airborne radioactive material through the gaseous effluent treatment system of a nuclear installation. The design, construction, and calibration of an experimental ventilation system to verify the fire and explosion accident analysis codes are described. The facility features a large industrial heater and several aerosol smoke generators that are used to simulate fires. Both injected thermal energy and aerosol mass can be controlled using this equipment. Explosions are simulated with H 2 /O 2 balloons and small explosive charges. Experimental measurements of temperature, energy, aerosol release rates, smoke concentration, and mass accumulation on HEPA filters can be made. Volumetric flow rate and differential pressures also are monitored. The initial experiments involve varying parameters such as thermal and aerosol rate and ventilation flow rate. FIRAC prediction results are presented. 10 figs

A computer code to estimate accidental fire and radioactive airborne releases in nuclear fuel cycle facilities: User's manual for FIRIN

International Nuclear Information System (INIS)

Chan, M.K.; Ballinger, M.Y.; Owczarski, P.C.

1989-02-01

This manual describes the technical bases and use of the computer code FIRIN. This code was developed to estimate the source term release of smoke and radioactive particles from potential fires in nuclear fuel cycle facilities. FIRIN is a product of a broader study, Fuel Cycle Accident Analysis, which Pacific Northwest Laboratory conducted for the US Nuclear Regulatory Commission. The technical bases of FIRIN consist of a nonradioactive fire source term model, compartment effects modeling, and radioactive source term models. These three elements interact with each other in the code affecting the course of the fire. This report also serves as a complete FIRIN user's manual. Included are the FIRIN code description with methods/algorithms of calculation and subroutines, code operating instructions with input requirements, and output descriptions. 40 refs., 5 figs., 31 tabs

Evaluation of macrolide resistance and enhanced molecular typing of Treponema pallidum in patients with syphilis in Taiwan: a prospective multicenter study.

Science.gov (United States)

Wu, Hsiu; Chang, Sui-Yuan; Lee, Nan-Yao; Huang, Wen-Chi; Wu, Bing-Ru; Yang, Chia-Jui; Liang, Shiou-Haur; Lee, Chen-Hsiang; Ko, Wen-Chien; Lin, Hsi-Hsun; Chen, Yen-Hsu; Liu, Wen-Chun; Su, Yi-Ching; Hsieh, Chia-Yin; Wu, Pei-Ying; Hung, Chien-Ching

2012-07-01

Studies of macrolide resistance mutations and molecular typing using the newly proposed enhanced typing system for Treponema pallidum isolates obtained from HIV-infected patients in the Asia-Pacific region are scarce. Between September 2009 and December 2011, we conducted a survey to detect T. pallidum using a PCR assay using clinical specimens from patients with syphilis at six major designated hospitals for HIV care in Taiwan. The T. pallidum strains were genotyped by following the enhanced molecular typing methodology, which analyzed the number of 60-bp repeats in the acidic repeat protein (arp) gene, T. pallidum repeat (tpr) polymorphism, and the sequence of base pairs 131 to 215 in the tp0548 open reading frame of T. pallidum. Detection of A2058G and A2059G point mutations in the T. pallidum 23S rRNA was performed with the use of restriction fragment length polymorphism (RFLP). During the 2-year study period, 211 clinical specimens were obtained from 136 patients with syphilis. T. pallidum DNA was isolated from 105 (49.8%) of the specimens, with swab specimens obtained from chancres having the highest yield rate (63.2%), followed by plasma (49.4%), serum (35.7%), and cerebrospinal fluid or vitreous fluid (18.2%) specimens. Among the 40 fully typed specimens, 11 subtypes of T. pallidum were identified. Subtype 14f/f (18 isolates) was the most common isolates, followed by 14f/c (3), 14b/c (3), and 14k/f (3). Among the isolates examined for macrolide resistance, none had the A2058G or A2059G mutation. In conclusion, we found that type 14 f/f was the most common T. pallidum strain in this multicenter study on syphilis in Taiwan and that none of the isolates exhibited 23S rRNA mutations causing resistance to macrolides.

Evaluation of the HISCL Anti-Treponema pallidum Assay as a Screening Test for Syphilis

OpenAIRE

An, Jingna; Chen, Qixia; Liu, Qianqian; Rao, Chenli; Li, Dongdong; Wang, Tingting; Tao, Chuanmin; Wang, Lanlan

2015-01-01

The resurgence of syphilis in recent years has become a serious threat to public health worldwide, and the serological detection of specific antibodies against Treponema pallidum remains the most reliable method for laboratory diagnosis of syphilis. This study examined the performance of the recently launched HISCL anti-Treponema pallidum (anti-TP) assay as a screening test for syphilis in a high-volume laboratory. The HISCL anti-TP assay was tested in 300 preselected syphilis-positive sample...

SPOOL-FIRE: an IBM 370/195 code for the analysis of combined spray and pool burning of sodium

International Nuclear Information System (INIS)

Charak, I.; Person, L.W.

1976-01-01

A code for the computation of the pressure and temperatures within a containment building as a result of a sodium fire is described. The fire is assumed to occur in two distinct phases: a spray and a pool. The spray fire is conservatively assumed to occur instantaneously. The pool fire model used is the SOFIRE-II model developed by Atomics International. The code calculates all important temperatures, accounting for heat loss from the building to the environment, as well as leakage of the containment atmosphere under conditions of internal overpressure. The IBM CSMP methodology is used to solve the set of ordinary differential equations which model the system. The use of CSMP allows the user considerable flexibility in modifying the models employed

Clovamide-rich extract from Trifolium pallidum reduces oxidative stress-induced damage to blood platelets and plasma.

Science.gov (United States)

Kolodziejczyk, Joanna; Olas, Beata; Wachowicz, Barbara; Szajwaj, Barbara; Stochmal, Anna; Oleszek, Wieslaw

2011-09-01

Numerous plants (including clovers) have been widely used in folk medicine for the treatment of different disorders. This in vitro study was designed to examine the antioxidative effects of the clovamide-rich fraction, obtained from aerial parts of Trifolium pallidum, in the protection of blood platelets and plasma against the nitrative and oxidative damage, caused by peroxynitrite (ONOO(-)). Carbonyl groups and 3-nitrotyrosine in blood platelet and plasma proteins were determined by ELISA tests. Thiol groups level was estimated by using 5,5'-dithio-bis(2-nitro-benzoic acid, DTNB). Plasma lipid peroxidation was measured spectrophotometrically as the production of thiobarbituric acid reactive substances. The results from our work indicate that clovamide-rich T. pallidum extract may reveal the protective properties in the prevention against oxidative stress. The presence of clovamide-rich T. pallidum extract (12.5-100 μg/ml) partly inhibited ONOO(-)-mediated protein carbonylation and nitration. All the used concentrations of T. pallidum extract reduced lipid peroxidation in plasma. The antioxidative action of the tested extract in the protection of blood platelet lipids was less effective; the extract at the lowest final concentration (12.5 μg/ml) had no protective effect against lipid peroxidation. The present results indicate that the extract from T. pallidum is likely to be a source of compounds with the antioxidative properties, useful in the prevention against the oxidative stress-related diseases.

Comparison of aerosol behavior codes with experimental results from a sodium fire in a containment

International Nuclear Information System (INIS)

Lhiaubet, G.; Kissane, M.P.; Seino, H.; Miyake, O.; Himeno, Y.

1990-01-01

The containment expert group (CONT), a subgroup of the CEC fast reactor Safety Working Group (SWG), has carried out several studies on the behavior of sodium aerosols which might form in a severe fast reactor accident during which primary sodium leaks into the secondary containment. These studies comprise an intercalibration of measurement devices used to determine the aerosol particle size spectrum, and the analysis and comparison of codes applied to the determination of aerosol behavior in a reactor containment. The paper outlines the results of measurements of typical data made for aerosols produced in a sodium fire and their comparison with results from different codes (PARDISEKO, AEROSIM, CONTAIN, AEROSOLS/B2). The sodium fire experiment took place at CEN-Cadarache (France) in a 400 m 3 vessel. The fire lasted 90 minutes and the aerosol measurements were made over 10 hours at different locations inside the vessel. The results showed that the suspended mass calculated along the time with different codes was in good agreement with the experiment. However, the calculated aerosol deposition on the walls was diverging and always significantly lower than the measured values

Seroprevalence of Treponema Pallidum in Donor Blood at the ...

African Journals Online (AJOL)

Objectives: To determine the Seroprevalence of Treponema pallidum in Donor blood at University of Benin Teaching Hospital Benin City. Materials and Method: This is a descriptive hospital based study. Donor blood supplied to the hospital blood bank was screened for syphilis. The study was conducted between February ...

Rapid Treponema pallidum clearance from blood and ulcer samples following single dose benzathine penicillin treatment of early syphilis.

Science.gov (United States)

Tipple, Craig; Jones, Rachael; McClure, Myra; Taylor, Graham

2015-02-01

Currently, the efficacy of syphilis treatment is measured with anti-lipid antibody tests. These can take months to indicate cure and, as a result, syphilis treatment trials require long periods of follow-up. The causative organism, Treponema pallidum (T. pallidum), is detectable in the infectious lesions of early syphilis using DNA amplification. Bacteraemia can likewise be identified, typically in more active disease. We hypothesise that bacterial clearance from blood and ulcers will predict early the standard serology-measured treatment response and have developed a qPCR assay that could monitor this clearance directly in patients with infectious syphilis. Patients with early syphilis were given an intramuscular dose of benzathine penicillin. To investigate the appropriate sampling timeframe samples of blood and ulcer exudate were collected intensively for T. pallidum DNA (tpp047 gene) and RNA (16S rRNA) quantification. Sampling ended when two consecutive PCRs were negative. Four males were recruited. The mean peak level of T. pallidum DNA was 1626 copies/ml whole blood and the mean clearance half-life was 5.7 hours (std. dev. 0.53). The mean peak of 16S rRNA was 8879 copies/ml whole blood with a clearance half-life of 3.9 hours (std. dev. 0.84). From an ulcer, pre-treatment, 67,400 T. pallidum DNA copies and 7.08 x 107 16S rRNA copies were detected per absorbance strip and the clearance half-lives were 3.2 and 4.1 hours, respectively. Overall, T. pallidum nucleic acids were not detected in any sample collected more than 56 hours (range 20-56) after treatment. All patients achieved serologic cure. In patients with active early syphilis, measuring T. pallidum levels in blood and ulcer exudate may be a useful measure of treatment success in therapeutic trials. These laboratory findings need confirmation on a larger scale and in patients receiving different therapies.

Rapid Treponema pallidum clearance from blood and ulcer samples following single dose benzathine penicillin treatment of early syphilis.

Directory of Open Access Journals (Sweden)

Craig Tipple

2015-02-01

Full Text Available Currently, the efficacy of syphilis treatment is measured with anti-lipid antibody tests. These can take months to indicate cure and, as a result, syphilis treatment trials require long periods of follow-up. The causative organism, Treponema pallidum (T. pallidum, is detectable in the infectious lesions of early syphilis using DNA amplification. Bacteraemia can likewise be identified, typically in more active disease. We hypothesise that bacterial clearance from blood and ulcers will predict early the standard serology-measured treatment response and have developed a qPCR assay that could monitor this clearance directly in patients with infectious syphilis. Patients with early syphilis were given an intramuscular dose of benzathine penicillin. To investigate the appropriate sampling timeframe samples of blood and ulcer exudate were collected intensively for T. pallidum DNA (tpp047 gene and RNA (16S rRNA quantification. Sampling ended when two consecutive PCRs were negative. Four males were recruited. The mean peak level of T. pallidum DNA was 1626 copies/ml whole blood and the mean clearance half-life was 5.7 hours (std. dev. 0.53. The mean peak of 16S rRNA was 8879 copies/ml whole blood with a clearance half-life of 3.9 hours (std. dev. 0.84. From an ulcer, pre-treatment, 67,400 T. pallidum DNA copies and 7.08 x 107 16S rRNA copies were detected per absorbance strip and the clearance half-lives were 3.2 and 4.1 hours, respectively. Overall, T. pallidum nucleic acids were not detected in any sample collected more than 56 hours (range 20-56 after treatment. All patients achieved serologic cure. In patients with active early syphilis, measuring T. pallidum levels in blood and ulcer exudate may be a useful measure of treatment success in therapeutic trials. These laboratory findings need confirmation on a larger scale and in patients receiving different therapies.

OECD-FIRE PR02. OECD-FIRE database record structure

International Nuclear Information System (INIS)

Kolar, L.

2005-12-01

In the coding guidelines, the scope, format, and details of any record required to input a real fire event at a nuclear reactor unit to the international OECD-FIRE database are described in detail. The database was set up in the OECD-FIRE-PR02 code

Purification, crystallization and preliminary X-ray analysis of TP0435 (Tp17) from the syphilis spirochete Treponema pallidum

International Nuclear Information System (INIS)

Brautigam, Chad A.; Deka, Ranjit K.; Norgard, Michael V.

2013-01-01

The soluble portion of TP0435, a putative periplasmic lipoprotein from the syphilis spirochete T. pallidum, has been purified and crystallized in a rhombohedral space group. A complete native data set has been collected to 2.4 Å resolution. Syphilis, caused by the bacterial spirochete Treponema pallidum, remains a prominent sexually transmitted infection worldwide. Despite sequencing of the genome of this obligate human pathogen 15 years ago, the functions of a large number of the gene products of T. pallidum are still unknown, particularly with respect to those of the organism’s periplasmic lipoproteins. To better understand their functions, a structural biology approach has been pursued. To this end, the soluble portion of the T. pallidum TP0435 lipoprotein (also known as Tp17) was cloned, hyper-expressed in Escherichia coli and purified to apparent homogeneity. The protein crystals obtained from this preparation diffracted to 2.4 Å resolution and had the symmetry of space group R3. In the hexagonal setting, the unit-cell parameters were a = b = 85.7, c = 85.4 Å

Identification of neural firing patterns, frequency and temporal coding mechanisms in individual aortic baroreceptors

Directory of Open Access Journals (Sweden)

Huaguang eGu

2015-08-01

Full Text Available In rabbit depressor nerve fibers, an on-off firing pattern, period-1 firing, and integer multiple firing with quiescent state were observed as the static pressure level was increased. A bursting pattern with bursts at the systolic phase of blood pressure, continuous firing, and bursting with burst at diastolic phase and quiescent state at systolic phase were observed as the mean level of the dynamic blood pressure was increased. For both static and dynamic pressures, the firing frequency of the first two firing patterns increased and of the last firing pattern decreased due to the quiescent state. If the quiescent state is disregarded, the spike frequency becomes an increasing trend. The instantaneous spike frequency of the systolic phase bursting, continuous firing, and diastolic phase bursting can reflect the temporal process of the systolic phase, whole procedure, and diastolic phase of the dynamic blood pressure signal, respectively. With increasing the static current corresponding to pressure level, the deterministic Hodgkin-Huxley (HH model manifests a process from a resting state first to period-1 firing via a subcritical Hopf bifurcation and then to a resting state via a supercritical Hopf bifurcation, and the firing frequency increases. The on-off firing and integer multiple firing were here identified as noise-induced firing patterns near the subcritical and supercritical Hopf bifurcation points, respectively, using the stochastic HH model. The systolic phase bursting and diastolic phase bursting were identified as pressure-induced firings near the subcritical and supercritical Hopf bifurcation points, respectively, using an HH model with a dynamic signal. The firing, spike frequency, and instantaneous spike frequency observed in the experiment were simulated and explained using HH models. The results illustrate the dynamics of different firing patterns and the frequency and temporal coding mechanisms of aortic baroreceptor.

Computer code structure for evaluation of fire protection measures and fighting capability at nuclear plants

International Nuclear Information System (INIS)

Anton, V.

1997-01-01

In this work a computer code structure for Fire Protection Measures (FPM) and Fire Fighting Capability (FFC) at Nuclear Power Plants (NPP) is presented. It allows to evaluate the category (satisfactory (s), needs for further evaluation (n), unsatisfactory (u)) to which belongs the given NPP for a self-control in view of an IAEA inspection. This possibility of a self assessment resulted from IAEA documents. Our approach is based on international experience gained in this field and stated in IAEA recommendations. As an illustration we used the FORTRAN programming language statement to make clear the structure of the computer code for the problem taken into account. This computer programme can be conceived so that some literal message in English and Romanian languages be displayed beside the percentage assessments. (author)

Human Treponema pallidum 11q/j isolate belongs to subsp. endemicum but contains two loci with a sequence in TP0548 and TP0488 similar to subsp. pertenue and subsp. pallidum, respectively.

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Lenka Mikalová

2017-03-01

Full Text Available Treponema pallidum subsp. endemicum (TEN is the causative agent of endemic syphilis (bejel. An unusual human TEN 11q/j isolate was obtained from a syphilis-like primary genital lesion from a patient that returned to France from Pakistan.The TEN 11q/j isolate was characterized using nested PCR followed by Sanger sequencing and/or direct Illumina sequencing. Altogether, 44 chromosomal regions were analyzed. Overall, the 11q/j isolate clustered with TEN strains Bosnia A and Iraq B as expected from previous TEN classification of the 11q/j isolate. However, the 11q/j sequence in a 505 bp-long region at the TP0488 locus was similar to Treponema pallidum subsp. pallidum (TPA strains, but not to TEN Bosnia A and Iraq B sequences, suggesting a recombination event at this locus. Similarly, the 11q/j sequence in a 613 bp-long region at the TP0548 locus was similar to Treponema pallidum subsp. pertenue (TPE strains, but not to TEN sequences.A detailed analysis of two recombinant loci found in the 11q/j clinical isolate revealed that the recombination event occurred just once, in the TP0488, with the donor sequence originating from a TPA strain. Since TEN Bosnia A and Iraq B were found to contain TPA-like sequences at the TP0548 locus, the recombination at TP0548 took place in a treponeme that was an ancestor to both TEN Bosnia A and Iraq B. The sequence of 11q/j isolate in TP0548 represents an ancestral TEN sequence that is similar to yaws-causing treponemes. In addition to the importance of the 11q/j isolate for reconstruction of the TEN phylogeny, this case emphasizes the possible role of TEN strains in development of syphilis-like lesions.

A longitudinal evaluation of Treponema pallidum PCR testing in early syphilis

Directory of Open Access Journals (Sweden)

Shields Matt

2012-12-01

Full Text Available Abstract Background Syphilis is a growing public health problem among men who have sex with men (MSM globally. Rapid and accurate detection of syphilis is vital to ensure patients and their contacts receive timely treatment and reduce ongoing transmission. Methods We evaluated a PCR assay for the diagnosis of Treponema pallidum using swabs of suspected early syphilis lesions in longitudinally assessed MSM. Results We tested 260 MSM for T pallidum by PCR on 288 occasions: 77 (26.7% had early syphilis that was serologically confirmed at baseline or within six weeks, and 211 (73.3% remained seronegative for syphilis. Of 55 men with primary syphilis, 49 were PCR positive, giving a sensitivity of 89.1% (95% CI: 77.8%-95.9% and a specificity of 99.1% (95% CI: 96.5%-99.9%. Of 22 men with secondary syphilis, 11 were PCR positive, giving a sensitivity of 50% (95% CI: 28.2%-71.8% and a specificity of 100% (95% CI: 66.4%-71.8%. Of the 77 syphilis cases, 43 (56% were HIV positive and the sensitivity and specificity of the PCR test did not vary by HIV status. The PCR test was able to detect up to five (10% primary infections that were initially seronegative, including one HIV positive man with delayed seroconversion to syphilis (72 to 140 days and one HIV positive man who did not seroconvert to syphilis over 14 months follow-up. Both men had been treated for syphilis within a week of the PCR test. Conclusions T pallidum PCR is a potentially powerful tool for the early diagnosis of primary syphilis, particularly where a serological response has yet to develop.

[Evaluation of the Recombinant Protein Tp0965 of Treponema Pallidum as Perspective Antigen for the Improved Serological Diagnosis of Syphilis].

Science.gov (United States)

Runina, A V; Starovoitova, A S; Deryabin, D G; Kubanov, A A

2016-01-01

BACKGRAUND. Treponemal tests based on the detection of antibodies against the Treponema pallidum antigens are the most specific methods for serological diagnosis of syphilis. Due to the inability to cultivate this bacterium in vitro, the most promising sources of antigens for diagnostics are recombinant proteins of T. pallidum. Evaluation of the analytical value of certain T. pallidum proteins is the approach to improve sensitivity, specificity, and reproducibility of syphilis serological tests, including possibilities of differential diagnosis of various forms of the disease. The aim of the research was to evaluate the analytical values (sensitivity and specificity) of recombinant protein Tp0965 of T. pallidum as a candidate antigen for serological diagnosis of syphilis. tp0965 gene was cloned into the expression vector pET28a and the construct was used for the transformation of E. coli BL-21 (DE3) cells and further expression and purification of the recombinant protein. The collected protein was used as T. pallidum antigen for serum analysis (ELISA) of groups of patients with various forms of syphilis (n=84) and the group of healthy donors (n = 25). High frequency of positive ELISA results was shown with serum of patients with syphilis, compared to the group of healthy donors. The sensitivity of serological reactions using recombinant protein Tp0965 was 98.8%, specificity--87.5%. The highest sensitivity (100%) was detected in the groups of patients with primary, secondary and early latent syphilis while in the group of patients with late latent syphilis it decreased to 95.2%. We concluded that due to its specificity T. pallidum recombinant protein Tp0965 can be used as a novel perspective antigen for development of syphilis serological diagnostic assays (for primary and early latent forms).

Focal lesions within the ventral striato-pallidum abolish attraction for male chemosignals in female mice.

Science.gov (United States)

Agustín-Pavón, Carmen; Martínez-García, Fernando; Lanuza, Enrique

2014-02-01

In rodents, socio-sexual behaviour is largely mediated by chemosensory cues, some of which are rewarding stimuli. Female mice display an innate attraction towards male chemosignals, dependent on the vomeronasal system. This behaviour likely reflects the hedonic value of sexual chemosignals. The anteromedial aspect of the olfactory tubercle, along with its associated islands of Calleja, receives vomeronasal inputs and sexually-dimorphic vasopressinergic innervation. Thus, we hypothesised that this portion of the ventral striato-pallidum, known to be involved in reward processing, might be important for sexual odorant-guided behaviours. In this study, we demonstrate that lesions of this region, but not of regions in the posterolateral striato-pallidum, abolish the attraction of female mice for male chemosignals, without affecting significantly their preference for a different natural reward (a sucrose solution). These results show that, at least in female mice, the integrity of the anterior aspect of the medioventral striato-pallidum, comprising a portion of the olfactory tubercle and associated islands of Calleja, is necessary for the attraction for male chemosignals. We suggest that this region contributes to the processing of the hedonic properties of biologically significant odorants. Copyright © 2013 Elsevier B.V. All rights reserved.

First Report of the 23S rRNA Gene A2058G Point Mutation Associated With Macrolide Resistance in Treponema pallidum From Syphilis Patients in Cuba.

Science.gov (United States)

Noda, Angel A; Matos, Nelvis; Blanco, Orestes; Rodríguez, Islay; Stamm, Lola Virginia

2016-05-01

This study aimed to assess the presence of macrolide-resistant Treponema pallidum subtypes in Havana, Cuba. Samples from 41 syphilis patients were tested for T. pallidum 23S rRNA gene mutations. Twenty-five patients (61%) harbored T. pallidum with the A2058G mutation, which was present in all 8 subtypes that were identified. The A2059G mutation was not detected.

Prevalencia de la infección por el VIH y de Treponema pallidum en mujeres trabajadoras sexuales de Argentina Prevalence of HIV infection and Treponema pallidum in Argentine female sex workers

Directory of Open Access Journals (Sweden)

María de los Ángeles Pando

2011-10-01

Full Text Available OBJETIVO: Estimar la prevalencia de infección por el virus de la inmunodeficiencia humana (VIH y de Treponema pallidum en mujeres trabajadoras sexuales (MTS de Argentina, y describir las características sociodemográficas de este grupo de población asociadas a la transmisión del VIH. MÉTODOS: Entre octubre de 2006 y diciembre de 2009 se realizó un estudio de corte transversal y un muestreo por conveniencia en MTS mayores de 18 años de nueve ciudades de Argentina. Un total de 1 255 mujeres participaron en este estudio. Se capacitó especialmente a un grupo de MTS para convocar a las otras mujeres a participar en talleres y a realizarse el diagnóstico del VIH y T. pallidum. RESULTADOS: Las características socio-epidemiológicas más destacadas de las MTS incluyeron un alto porcentaje de abuso sexual, escaso uso de preservativos con parejas sexuales no comerciales y un alto porcentaje de situaciones de violencia. La prevalencia del VIH fue de 2% (25/1 255, intervalo de confianza de 95% [IC95%]:1,2-2,8 y la de T. pallidum, de 22,4% (245/ 1 094, IC95%: 19,9-24,9. En las MTS de la ciudad de La Plata, la prevalencia del VIH fue significativamente más baja comparada con las participantes del resto del país (0,3% vs 2,7%, P OBJECTIVE: Estimate the prevalence of human immunodeficiency virus (HIV infection and Treponema pallidum in Argentine female sex workers (FSW, and describe the sociodemographic characteristics of this population group associated with HIV transmission. METHODS: A cross-sectional study and convenience sampling were conducted in FSW over 18 years of age in nine Argentine cities from October 2006 to December 2009. A total of 1 255 women participated in this study. A group of FSW was especially trained to invite other women to participate in the workshops and undergo screening for HIV and T. pallidum. RESULTS: The most noteworthy socioepidemiological characteristics of the FSW included a high percentage of sexual abuse, limited

Calculation of Sodium Fire Test-I (Run-E6) using sodium combustion analysis code ASSCOPS version 2.0

Energy Technology Data Exchange (ETDEWEB)

Nakagiri, Toshio; Ohno, Shuji; Miyake, Osamu [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center

1997-11-01

The calculation of Sodium Fire Test-I (Run-E6) was performed using the ASSCOPS (Analysis of Simultaneous Sodium Combustions in Pool and Spray) code version 2.0 in order to determine the parameters used in the code for the calculations of sodium combustion behavior of small or medium scale sodium leak, and to validate the applicability of the code. The parameters used in the code were determined and the validation of the code was confirmed because calculated temperatures, calculated oxygen concentration and other calculated values almost agreed with the test results. (author)

Computer code TRANS-ACE predicting for fire and explosion accidents in nuclear fuel reprocessing plants

International Nuclear Information System (INIS)

Abe, Hitoshi; Nishio; Gunji; Naito, Yoshitaka

1993-11-01

The accident analysis code TRANS-ACE was developed to evaluate the safety of a ventilation system in a reprocessing plant in the event of fire and explosion accidents. TRANS-ACE can evaluate not only the integrity of a ventilation system containing HEPA filters but also the source term of radioactive materials for release out of a plant. It calculates the temperature, pressure, flow rate, transport of combustion materials and confinement of radioactive materials in the network of a ventilation system that might experience a fire or explosion accident. TRANS-ACE is based on the one-dimensional compressible thermo-fluid analysis code EVENT developed by Los Alamos National Laboratory (LANL). Calculational functions are added for the radioactive source term, heat transfer and radiation to cell and duct walls and HEPA filter integrity. For the second edition in the report, TRANS-ACE has been improved incorporating functions for the initial steady-state calculation to determine the flow rates, pressure drops and temperature in the network before an accident mode analysis. It is also improved to include flow resistance calculations of the filters and blowers in the network and to have an easy to use code by simplifying the input formats. This report is to prepare an explanation of the mathematical model for TRANS-ACE code and to be the user's manual. (author)

A memristive spiking neuron with firing rate coding

Directory of Open Access Journals (Sweden)

Marina eIgnatov

2015-10-01

Full Text Available Perception, decisions, and sensations are all encoded into trains of action potentials in the brain. The relation between stimulus strength and all-or-nothing spiking of neurons is widely believed to be the basis of this coding. This initiated the development of spiking neuron models; one of today's most powerful conceptual tool for the analysis and emulation of neural dynamics. The success of electronic circuit models and their physical realization within silicon field-effect transistor circuits lead to elegant technical approaches. Recently, the spectrum of electronic devices for neural computing has been extended by memristive devices, mainly used to emulate static synaptic functionality. Their capabilities for emulations of neural activity were recently demonstrated using a memristive neuristor circuit, while a memristive neuron circuit has so far been elusive. Here, a spiking neuron model is experimentally realized in a compact circuit comprising memristive and memcapacitive devices based on the strongly correlated electron material vanadium dioxide (VO2 and on the chemical electromigration cell Ag/TiO2-x/Al. The circuit can emulate dynamical spiking patterns in response to an external stimulus including adaptation, which is at the heart of firing rate coding as first observed by E.D. Adrian in 1926.

Clinical Value of Treponema pallidum Real-Time PCR for Diagnosis of Syphilis

NARCIS (Netherlands)

Heymans, R.; van der Helm, J. J.; de Vries, H. J. C.; Fennema, H. S. A.; Coutinho, R. A.; Bruisten, S. M.

2010-01-01

The diagnosis of syphilis can be complicated when it is based on diverse clinical manifestations, dark-field microscopy, and serology. In the present study, therefore, we examined the additional clinical value of a Treponema pallidum real-time TaqMan PCR for the detection of primary and secondary

Fire safety of wood construction

Science.gov (United States)

Robert H. White; Mark A. Dietenberger

2010-01-01

Fire safety is an important concern in all types of construction. The high level of national concern for fire safety is reflected in limitations and design requirements in building codes. These code requirements and related fire performance data are discussed in the context of fire safety design and evaluation in the initial section of this chapter. Because basic data...

Fire safety assessment for the fire areas of the nuclear power plant using fire model CFAST

International Nuclear Information System (INIS)

Lee, Yoon Hwan; Yang, Joon Eon; Kim, Jong Hoon

2005-03-01

Now the deterministic analysis results for the cable integrity is not given in case of performing the fire PSA. So it is necessary to develop the assessment methodology for the fire growth and propagation. This document is intended to analyze the peak temperature of the upper gas layer using the fire modeling code, CFAST, to evaluate the integrity of the cable located on the dominant pump rooms, and to assess the CCDP(Conditional Core Damage Probability) using the results of the cable integrity. According to the analysis results, the cable integrity of the pump rooms is maintained and CCDP is reduced about two times than the old one. Accordingly, the fire safety assessment for the dominant fire areas using the fire modeling code will capable to reduce the uncertainty and to develop a more realistic model

Seroprevalence of Human Immunodeficiency Virus, Hepatitis B Virus, Hepatitis C Virus, and Treponema pallidum Infections among Blood Donors on Bioko Island, Equatorial Guinea.

Directory of Open Access Journals (Sweden)

Dong-De Xie

Full Text Available Regular screening of transfusion-transmissible infections (TTIs, such as human immunodeficiency virus (HIV, hepatitis B and hepatitis C virus (HBV and HCV, respectively, and Treponema pallidum, in blood donors is essential to guaranteeing clinical transfusion safety. This study aimed to determine the seroprevalence of four TTIs among blood donors on Bioko Island, Equatorial Guinea (EG.A retrospective survey of blood donors from January 2011 to April 2013 was conducted to assess the presence of HIV, HBV, HCV and T. pallidum. The medical records were analyzed to verify the seroprevalence of these TTIs among blood donations stratified by gender, age and geographical region.Of the total 2937 consecutive blood donors, 1098 (37.39% had a minimum of one TTI and 185 (6.29% harbored co-infections. The general seroprevalence of HIV, HBV, HCV and T. pallidum were 7.83%, 10.01%, 3.71% and 21.51%, respectively. The most frequent TTI co-infections were HBV-T. pallidum 60 (2.04% and HIV-T. pallidum 46 (1.57%. The seroprevalence of HIV, HBV, HCV and T. pallidum were highest among blood donors 38 to 47 years, 18 to 27 years and ≥ 48 years age, respectively (P<0.05. The seroprevalence of TTIs varied according to the population from which the blood was collected on Bioko Island.Our results firstly provide a comprehensive overview of TTIs among blood donors on Bioko Island. Strict screening of blood donors and improved hematological examinations using standard operating procedures are recommended.

Osteitis in the dens of axis caused by Treponema pallidum

DEFF Research Database (Denmark)

Fabricius, Thilde; Winther, Charlotte; Ewertsen, Caroline

2013-01-01

Syphilis has been referred to as "the great imitator" due to its ability to imitate other diseases. Untreated syphilis becomes a systemic infection that can involve almost every organ systems. Treponema pallidum has a high affinity for bone tissue, but osteitis has mainly been described in late...... stages of the disease. Vertebral involvement is rare, and this is to our knowledge the first case describing syphilitic spondylitis in early acquired syphilis....

Development of a Multilocus Sequence Typing (MLST) scheme for Treponema pallidum subsp. pertenue: Application to yaws in Lihir Island, Papua New Guinea.

Science.gov (United States)

Godornes, Charmie; Giacani, Lorenzo; Barry, Alyssa E; Mitja, Oriol; Lukehart, Sheila A

2017-12-01

Yaws is a neglected tropical disease, caused by Treponema pallidum subsp. pertenue. The disease causes chronic lesions, primarily in young children living in remote villages in tropical climates. As part of a global yaws eradication campaign initiated by the World Health Organization, we sought to develop and evaluate a molecular typing method to distinguish different strains of T. pallidum subsp. pertenue for disease control and epidemiological purposes. Published genome sequences of strains of T. pallidum subsp. pertenue and pallidum were compared to identify polymorphic genetic loci among the strains. DNA from a number of existing historical Treponema isolates, as well as a subset of samples from yaws patients collected in Lihir Island, Papua New Guinea, were analyzed using these targets. From these data, three genes (tp0548, tp0136 and tp0326) were ultimately selected to give a high discriminating capability among the T. pallidum subsp. pertenue samples tested. Intragenic regions of these three target genes were then selected to enhance the discriminating capability of the typing scheme using short readily amplifiable loci. This 3-gene multilocus sequence typing (MLST) method was applied to existing historical human yaws strains, the Fribourg-Blanc simian isolate, and DNA from 194 lesion swabs from yaws patients on Lihir Island, Papua New Guinea. Among all samples tested, fourteen molecular types were identified, seven of which were found in patient samples and seven among historical isolates or DNA. Three types (JG8, TD6, and SE7) were predominant on Lihir Island. This MLST approach allows molecular typing and differentiation of yaws strains. This method could be a useful tool to complement epidemiological studies in regions where T. pallidum subsp. pertenue is prevalent with the overall goals of improving our understanding of yaws transmission dynamics and helping the yaws eradication campaign to succeed.

Development of a Multilocus Sequence Typing (MLST) scheme for Treponema pallidum subsp. pertenue: Application to yaws in Lihir Island, Papua New Guinea

Science.gov (United States)

Godornes, Charmie; Giacani, Lorenzo; Barry, Alyssa E.; Mitja, Oriol

2017-01-01

Background Yaws is a neglected tropical disease, caused by Treponema pallidum subsp. pertenue. The disease causes chronic lesions, primarily in young children living in remote villages in tropical climates. As part of a global yaws eradication campaign initiated by the World Health Organization, we sought to develop and evaluate a molecular typing method to distinguish different strains of T. pallidum subsp. pertenue for disease control and epidemiological purposes. Methods and principal findings Published genome sequences of strains of T. pallidum subsp. pertenue and pallidum were compared to identify polymorphic genetic loci among the strains. DNA from a number of existing historical Treponema isolates, as well as a subset of samples from yaws patients collected in Lihir Island, Papua New Guinea, were analyzed using these targets. From these data, three genes (tp0548, tp0136 and tp0326) were ultimately selected to give a high discriminating capability among the T. pallidum subsp. pertenue samples tested. Intragenic regions of these three target genes were then selected to enhance the discriminating capability of the typing scheme using short readily amplifiable loci. This 3-gene multilocus sequence typing (MLST) method was applied to existing historical human yaws strains, the Fribourg-Blanc simian isolate, and DNA from 194 lesion swabs from yaws patients on Lihir Island, Papua New Guinea. Among all samples tested, fourteen molecular types were identified, seven of which were found in patient samples and seven among historical isolates or DNA. Three types (JG8, TD6, and SE7) were predominant on Lihir Island. Conclusions This MLST approach allows molecular typing and differentiation of yaws strains. This method could be a useful tool to complement epidemiological studies in regions where T. pallidum subsp. pertenue is prevalent with the overall goals of improving our understanding of yaws transmission dynamics and helping the yaws eradication campaign to succeed

Duct System Flammability and Air Sealing Fire Separation Assemblies in the International Residential Code

Energy Technology Data Exchange (ETDEWEB)

Rudd, A. [ABT Systems, LLC, Annville, PA (United States); Prahl, D. [IBACOS, Inc., Pittsburgh, PA (United States)

2014-12-01

IBACOS identified two barriers that limit the ability of builders to cost-effectively achieve higher energy efficiency levels in housing. These are the use of duct system materials that inherently achieve airtightness and are appropriately sized for low-load houses and the ability to air seal fire separation assemblies. The issues identified fall into a gray area of the codes.

Duct System Flammability and Air Sealing Fire Separation Assemblies in the International Residential Code

Energy Technology Data Exchange (ETDEWEB)

Rudd, A.; Prahl, D.

2014-12-01

IBACOS identified two barriers that limit the ability of builders to cost-effectively achieve higher energy efficiency levels in housing. These are (1) the use of duct system materials that inherently achieve airtightness and are appropriately sized for low-load houses and (2) the ability to air seal fire separation assemblies. The issues identified fall into a gray area of the codes.

Whole Genome Sequences of Three Treponema pallidum ssp. pertenue Strains: Yaws and Syphilis Treponemes Differ in Less than 0.2% of the Genome Sequence

Science.gov (United States)

Chen, Lei; Pospíšilová, Petra; Strouhal, Michal; Qin, Xiang; Mikalová, Lenka; Norris, Steven J.; Muzny, Donna M.; Gibbs, Richard A.; Fulton, Lucinda L.; Sodergren, Erica; Weinstock, George M.; Šmajs, David

2012-01-01

Background The yaws treponemes, Treponema pallidum ssp. pertenue (TPE) strains, are closely related to syphilis causing strains of Treponema pallidum ssp. pallidum (TPA). Both yaws and syphilis are distinguished on the basis of epidemiological characteristics, clinical symptoms, and several genetic signatures of the corresponding causative agents. Methodology/Principal Findings To precisely define genetic differences between TPA and TPE, high-quality whole genome sequences of three TPE strains (Samoa D, CDC-2, Gauthier) were determined using next-generation sequencing techniques. TPE genome sequences were compared to four genomes of TPA strains (Nichols, DAL-1, SS14, Chicago). The genome structure was identical in all three TPE strains with similar length ranging between 1,139,330 bp and 1,139,744 bp. No major genome rearrangements were found when compared to the four TPA genomes. The whole genome nucleotide divergence (dA) between TPA and TPE subspecies was 4.7 and 4.8 times higher than the observed nucleotide diversity (π) among TPA and TPE strains, respectively, corresponding to 99.8% identity between TPA and TPE genomes. A set of 97 (9.9%) TPE genes encoded proteins containing two or more amino acid replacements or other major sequence changes. The TPE divergent genes were mostly from the group encoding potential virulence factors and genes encoding proteins with unknown function. Conclusions/Significance Hypothetical genes, with genetic differences, consistently found between TPE and TPA strains are candidates for syphilitic treponemes virulence factors. Seventeen TPE genes were predicted under positive selection, and eleven of them coded either for predicted exported proteins or membrane proteins suggesting their possible association with the cell surface. Sequence changes between TPE and TPA strains and changes specific to individual strains represent suitable targets for subspecies- and strain-specific molecular diagnostics. PMID:22292095

The numerical comparison of fire combustion model and water-mist suppression with experiments by FDS code

International Nuclear Information System (INIS)

Li Hsuennien; Ferng Yuhming; Shih Chunkuan; Hsu Wensheng

2007-01-01

FDS [1] code numerically solves a form of the Navier-Stokes equations appropriate for low-speed, thermally driven flow with an emphasis on smoke and heat transport from fires. FDS uses a mixture fraction combustion model. The mixture fraction is a conserved scalar quantity that is defined as the fraction of fuel gas at a given point in the flow field. The model assumes that combustion is mixing-controlled, and that the reaction of fuel and oxygen is infinitely fast. In FDS, Lagrangian particles are used to simulate smoke movement and sprinkling water-mist discharge. In order to evaluate the combustion model and water-mist suppression function of the code, FDS analyses are conducted to simulate two enclosure fire cases available in the literature. Comparisons with other combustion models are also made. For fires suppression by water-mist in FDS, parametric studies are performed to compare various water-mist injection characteristics for maximum suppression. Numerical results indicate that the flame suppression is closely related to characteristics of the water mist, such as droplet diameter, mist injection velocity, injection density. Our present investigations show that the combustion model and water-mist suppression in FDS can provide simulation results that are comparable with the experiments. (author)

Treponema pallidum 3-Phosphoglycerate Mutase Is a Heat-Labile Enzyme That May Limit the Maximum Growth Temperature for the Spirochete

Science.gov (United States)

Benoit, Stéphane; Posey, James E.; Chenoweth, Matthew R.; Gherardini, Frank C.

2001-01-01

In the causative agent of syphilis, Treponema pallidum, the gene encoding 3-phosphoglycerate mutase, gpm, is part of a six-gene operon (tro operon) that is regulated by the Mn-dependent repressor TroR. Since substrate-level phosphorylation via the Embden-Meyerhof pathway is the principal way to generate ATP in T. pallidum and Gpm is a key enzyme in this pathway, Mn could exert a regulatory effect on central metabolism in this bacterium. To study this, T. pallidum gpm was cloned, Gpm was purified from Escherichia coli, and antiserum against the recombinant protein was raised. Immunoblots indicated that Gpm was expressed in freshly extracted infective T. pallidum. Enzyme assays indicated that Gpm did not require Mn2+ while 2,3-diphosphoglycerate (DPG) was required for maximum activity. Consistent with these observations, Mn did not copurify with Gpm. The purified Gpm was stable for more than 4 h at 25°C, retained only 50% activity after incubation for 20 min at 34°C or 10 min at 37°C, and was completely inactive after 10 min at 42°C. The temperature effect was attenuated when 1 mM DPG was added to the assay mixture. The recombinant Gpm from pSLB2 complemented E. coli strain PL225 (gpm) and restored growth on minimal glucose medium in a temperature-dependent manner. Increasing the temperature of cultures of E. coli PL225 harboring pSLB2 from 34 to 42°C resulted in a 7- to 11-h period in which no growth occurred (compared to wild-type E. coli). These data suggest that biochemical properties of Gpm could be one contributing factor to the heat sensitivity of T. pallidum. PMID:11466272

Standpipe systems for fire protection

CERN Document Server

Isman, Kenneth E

2017-01-01

This important new manual goes beyond the published NFPA standards on installation of standpipe systems to include the rules in the International Building Code, municipal fire codes, the National Fire Code of Canada, and information on inspection, testing, and maintenance of standpipe systems. Also covered are the interactions between standpipe and sprinkler systems, since these important fire protection systems are so frequently installed together. Illustrated with design examples and practical applications to reinforce the learning experience, this is the go-to reference for engineers, architects, design technicians, building inspectors, fire inspectors, and anyone that inspects, tests or maintains fire protection systems. Fire marshals and plan review authorities that have the responsibility for reviewing and accepting plans and hydraulic calculations for standpipe systems are also an important audience, as are firefighters who actually use standpipe systems. As a member of the committees responsible for s...

76 FR 70413 - National Fire Protection Association (NFPA): Request for Comments on NFPA's Codes and Standards

Science.gov (United States)

2011-11-14

... Private Fire Protection. P NFPA 36 Standard for Solvent Extraction Plants P NFPA 52 Vehicular Gaseous Fuel Systems Code P NFPA 67 Guideline on Explosion Protection for Gaseous N Mixtures in Pipe Systems. NFPA 68 Standard on Explosion Protection by Deflagration P Venting. NFPA 70B Recommended Practice for Electrical...

Advanced numerical modelling of a fire. Final report

International Nuclear Information System (INIS)

Heikkilae, L.; Keski-Rahkonen, O.

1996-03-01

Experience and probabilistic risk assessments show that fires present a major hazard in a nuclear power plant (NPP). The PALOME project (1988-92) improved the quality of numerical simulation of fires to make it a useful tool for fire safety analysis. Some of the most advanced zone model fire simulation codes were acquired. The performance of the codes was studied through literature and personal interviews in earlier studies and BRI2 code from the Japanese Building Research Institute was selected for further use. In PALOME 2 project this work was continued. Information obtained from large-scale fire tests at the German HDR facility allowed reliable prediction of the rate of heat release and was used for code validation. BRI2 code was validated particularly by participation in the CEC standard problem 'Prediction of effects caused by a cable fire experiment within the HDR-facility'. Participation in the development of a new field model code SOFIE specifically for fire applications as British-Swedish-Finnish cooperation was one of the goals of the project. SOFIE code was implemented at VTT and the first results of validation simulations were obtained. Well instrumented fire tests on electronic cabinets were carried out to determine source terms for simulation of room fires and to estimate fire spread to adjacent cabinets. The particular aim of this study was to measure the rate of heat release from a fire in an electronic cabinet. From the three tests, differing mainly in the amount of the fire load, data was obtained for source terms in numerical modelling of fires in rooms containing electronic cabinets. On the basis of these tests also a simple natural ventilation model was derived. (19 refs.)

A double-edged sword: does highly active antiretroviral therapy contribute to syphilis incidence by impairing immunity to Treponema pallidum?

Science.gov (United States)

Rekart, Michael L; Ndifon, Wilfred; Brunham, Robert C; Dushoff, Jonathan; Park, Sang Woo; Rawat, Sanjana; Cameron, Caroline E

2017-08-01

Recently, the world has experienced a rapidly escalating outbreak of infectious syphilis primarily affecting men who have sex with men (MSM); many are taking highly active antiretroviral therapy (HAART) for HIV-1 infection. The prevailing hypothesis is that HAART availability and effectiveness have led to the perception among both individuals who are HIV-1 infected and those who are uninfected that HIV-1 transmission has become much less likely, and the effects of HIV-1 infection less deadly. This is expected to result in increased sexual risk-taking, especially unprotected anal intercourse, leading to more non-HIV-1 STDs, including gonorrhoea, chlamydia and syphilis. However, syphilis incidence has increased more rapidly than other STDs. We hypothesise that HAART downregulates the innate and acquired immune responses to Treponema pallidum and that this biological explanation plays an important role in the syphilis epidemic. We performed a literature search and developed a mathematical model of HIV-1 and T. pallidum confection in a population with two risk groups with assortative mixing to explore the consequence on syphilis prevalence of HAART-induced changes in behaviour versus HAART-induced biological effects. Since rising syphilis incidence appears to have outpaced gonorrhoea and chlamydia, predominantly affecting HIV-1 positive MSM, behavioural factors alone may be insufficient to explain the unique, sharp increase in syphilis incidence. HAART agents have the potential to alter the innate and acquired immune responses in ways that may enhance susceptibility to T. pallidum . This raises the possibility that therapeutic and preventative HAART may inadvertently increase the incidence of syphilis, a situation that would have significant and global public health implications. We propose that additional studies investigating the interplay between HAART and enhanced T. pallidum susceptibility are needed. If our hypothesis is correct, HAART should be combined with

Fire risk analysis, fire simulation, fire spreading and impact of smoke and heat on instrumentation electronics - State-of-the-Art Report

International Nuclear Information System (INIS)

Roewekamp, M.; Bertrand, R.; Bonneval, F.; Hamblen, D.; Siu, N.; Aulamo, H.; Martila, J.; Sandberg, J.; Virolainen, R.

2000-01-01

Numerous fire PSAs (probabilistic safety assessments) have shown that fire can be a major contributor to nuclear power plant risk. However, there are considerable uncertainties in the results of these assessments, due to significant gaps in current abilities to perform realistic assessments. These gaps involve multiple aspects of fire PSA, including the estimation of the probability of important fire scenarios, the modeling of fire growth and suppression, the prediction of fire-induced damage to equipment (including the effects of smoke), and the treatment of plant and operator responses to the fire. In response to recommendations of /VIR 93/, CSNI/PWG5 established a Task Group to review the present status and maturity of current methods used in fire risk assessments for operating nuclear power plants. The Task Group issued a questionnaire in May 1997 to all nuclear power generating OECD countries. The prime focus of the questionnaire (see Appendix A) was on a number of important issues in fire PSA: Fire PSA methodology and applications; Fire simulation codes; Ignition and damageability data; Modeling of fire spread on cables or other equipment; Modeling of smoke production and spread; Impact of smoke and heat on instrumentation, electronics, or other electrical equipment; Impact of actual cable fires on safety systems. The questionnaire requested specific information on these topics (e.g., computer codes used in fire PSAs, the physical parameters used to model ignition). Responses to the questionnaire were provided by Finland, France, Germany, Hungary, Japan, Spain, Switzerland, United Kingdom, and the USA. This report summarizes the questionnaire responses and thereby: a) provides a perspective on the current fire PSA state of the art (SOAR) with respect to the issues listed above, and b) provides numerous references for more detailed information regarding these issues. The main responsibility for writing different chapters of this report was divided between some

Deep brain stimulation changes basal ganglia output nuclei firing pattern in the dystonic hamster.

Science.gov (United States)

Leblois, Arthur; Reese, René; Labarre, David; Hamann, Melanie; Richter, Angelika; Boraud, Thomas; Meissner, Wassilios G

2010-05-01

Dystonia is a heterogeneous syndrome of movement disorders characterized by involuntary muscle contractions leading to abnormal movements and postures. While medical treatment is often ineffective, deep brain stimulation (DBS) of the internal pallidum improves dystonia. Here, we studied the impact of DBS in the entopeduncular nucleus (EP), the rodent equivalent of the human globus pallidus internus, on basal ganglia output in the dt(sz)-hamster, a well-characterized model of dystonia by extracellular recordings. Previous work has shown that EP-DBS improves dystonic symptoms in dt(sz)-hamsters. We report that EP-DBS changes firing pattern in the EP, most neurons switching to a less regular firing pattern during DBS. In contrast, EP-DBS did not change the average firing rate of EP neurons. EP neurons display multiphasic responses to each stimulation impulse, likely underlying the disruption of their firing rhythm. Finally, neurons in the substantia nigra pars reticulata display similar responses to EP-DBS, supporting the idea that EP-DBS affects basal ganglia output activity through the activation of common afferent fibers. Copyright 2010 Elsevier Inc. All rights reserved.

Specific and sensitive diagnosis of syphilis using a real-time PCR for Treponema pallidum

NARCIS (Netherlands)

Koek, A. G.; Bruisten, S. M.; Dierdorp, M.; van Dam, A. P.; Templeton, K.

2006-01-01

A real-time PCR assay with a Taqman probe was developed that targeted the polA gene of Treponema pallidum. The test was validated using an analytical panel (n = 140) and a clinical panel of genital samples (n = 112) from patients attending a sexually transmitted infections clinic. High sensitivities

Adjuvant Activity of Sargassum pallidum Polysaccharides against Combined Newcastle Disease, Infectious Bronchitis and Avian Influenza Inactivated Vaccines

Directory of Open Access Journals (Sweden)

Li-Jie Li

2012-11-01

Full Text Available This study evaluates the effects of Sargassum pallidum polysaccharides (SPP on the immune responses in a chicken model. The adjuvanticity of Sargassum pallidum polysaccharides in Newcastle disease (ND, infectious bronchitis (IB and avian influenza (AI was investigated by examining the antibody titers and lymphocyte proliferation following immunization in chickens. The chickens were administrated combined ND, IB and AI inactivated vaccines containing SPP at 10, 30 and 50 mg/mL, using an oil adjuvant vaccine as a control. The ND, IB and AI antibody titers and the lymphocyte proliferation were enhanced at 30 mg/mL SPP. In conclusion, an appropriate dose of SPP may be a safe and efficacious immune stimulator candidate that is suitable for vaccines to produce early and persistent prophylaxis.

Improvement of fire protection measures for nuclear power plants

International Nuclear Information System (INIS)

2012-01-01

Improvements of fire protection measures for nuclear power plants were performed as following items: Development of fire hazard analysis method. Application of developed Fire Dynamic tool to actual plants, With regard to fire tests for the fire data acquisition, cable fire test and oil fire test were performed. Implementation of fire hazard analysis code and simulation were performed as following items: Fire analysis codes FDS, SYLVIA, CFAST were implemented in order to analyze the fire progression phenomena, Trial simulation of fire hazard as Metal-Clad Switch Gear Fire of ONAGAWA NPP in Tohoku earthquake (HEAF accident). (author)

78 FR 18321 - International Code Council: The Update Process for the International Codes and Standards

Science.gov (United States)

2013-03-26

... Energy Conservation Code. International Existing Building Code. International Fire Code. International... Code. International Property Maintenance Code. International Residential Code. International Swimming Pool and Spa Code International Wildland-Urban Interface Code. International Zoning Code. ICC Standards...

Analysis of large urban fires

International Nuclear Information System (INIS)

Kang, S.W.; Reitter, T.A.; Takata, A.N.

1984-11-01

Fires in urban areas caused by a nuclear burst are analyzed as a first step towards determining their smoke-generation chacteristics, which may have grave implications for global-scale climatic consequences. A chain of events and their component processes which would follow a nuclear attack are described. A numerical code is currently being developed to calculate ultimately the smoke production rate for a given attack scenario. Available models for most of the processes are incorporated into the code. Sample calculations of urban fire-development history performed in the code for an idealized uniform city are presented. Preliminary results indicate the importance of the wind, thermal radiation transmission, fuel distributions, and ignition thresholds on the urban fire spread characteristics. Future plans are to improve the existing models and develop new ones to characterize smoke production from large urban fires. 21 references, 18 figures

Improvement of fire protection measures for nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-08-15

Improvements of fire protection measures for nuclear power plants were performed as following items: Development of fire hazard analysis method. Application of developed Fire Dynamic Tool to actual plants (FDT{sup S}), With regard to fire tests for the fire data acquisition, cable fire test and High Energy Arcing Faults (HEAF) fire test were performed. Implementation of fire hazard analysis code and simulation were performed as following items: Fire analysis codes FDS, SYLVIA, and CFAST were implemented in order to analyze the fire progression phenomena. Trial simulation of HEAF accident of Onagawa NPP in Tohoku earthquake. (author)

75 FR 19944 - International Code Council: The Update Process for the International Codes and Standards

Science.gov (United States)

2010-04-16

... documents from ICC's Chicago District Office: International Code Council, 4051 W Flossmoor Road, Country... Energy Conservation Code. International Existing Building Code. International Fire Code. International...

Fire precautions at petroleum refineries and bulk storage installations

Energy Technology Data Exchange (ETDEWEB)

1993-10-01

Topics covered in this Code of Practice include petroleum products and combustion, site evaluation for fire defence, and fire prevention, protection, detection, systems, fighting, and fire fighting facilities in storage areas. Appendices cover legal requirements and enforcement arrangements, application rates for fire water and foam, codes of practice, flammable limits of petroleum compounds, flash points and spontaneous ignition temperatures and classification of fires. (UK)

Correlation for predicting aerosol concentration in sodium spray fires

International Nuclear Information System (INIS)

Marimuthu, K.

2001-01-01

Aerosol behaviour computer codes are reported for the study of time-dependent airborne aerosol concentration in a containment. The use of available computer codes requires a thorough knowledge of the various rate processes employed to describe the aerosol behaviour. The present work describes a simple empirical equation to calculate sodium fire aerosol concentration with respect to time in a containment and is applicable to sodium spray fire conditions. Sodium spray fire aerosol concentration values obtained using this simplified approach agree reasonably well with experimental results. The empirical equation described in the present work is incorporated in the spray fire code NACOM and the code calculated values of aerosol concentration agreement with the sodium spray fire experimental results is reasonably good. (author)

RCC-F: Design and construction rules for PWR fire protection systems

International Nuclear Information System (INIS)

2013-01-01

The RCC-F code defines the rules for designing, building and installing the fire protection systems used to manage the nuclear hazards inherent in the outbreak of a fire inside the facility and thereby control the fundamental nuclear functions. The code provides fire protection recommendations in terms of: the industrial risk (loss of assets and/or operation), personnel safety, the environment. The code is divided into five main sections: generalities, design safety principles, fire protection design bases, construction provisions, rules for installing the fire protection components and equipment. The RCC-F code is available as an ETC-F version specifically for EPR projects (European pressurized reactor). Contents of the 2013 edition of the ETC-F code: Volume A - Generalities: Structure of ETC-F general points, documentation (in progress), chapter (provision) quality assurance; Volume B - Design safety principles: design nuclear safety principles; Volume C - Fire protection design bases: fire protection design bases; Volume D - Construction provisions: construction provisions; Volume E - Installation rules for fire protection: rules for installing the fire protection, components and equipment

SNL/JAEA Collaborations on Sodium Fire Benchmarking.

Energy Technology Data Exchange (ETDEWEB)

Clark, Andrew Jordan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Denman, Matthew R [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Takata, Takashi [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ohshima, Hiroyuki [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-11-01

Two sodium spray fire experiments performed by Sandia National Laboratories (SNL) were used for a code - to - code comparison between CONTAIN - LMR and SPHINCS. Both computer codes are used for modeling sodium accidents in sodium fast reactors. The comparison between the two codes provides insights into the ability of both codes to model sodium spray fires. The SNL T3 and T4 experiments are 20 kg sodium spray fires with sodium spray temperature s of 200 deg C and 500 deg C, respe ctively. Given the relatively low sodium temperature in the SNL T3 experiment, the sodium spray experienced a period of non - combustion. The vessel in the SNL T4 experiment experienced a rapid pressurization that caused of the instrumentation ports to fail during the sodium spray. Despite these unforeseen difficulties, both codes were shown in good agreement with the experiment s . The subsequent pool fire that develops from the unburned sodium spray is a significant characteristic of the T3 experiment. SPHIN CS showed better long - term agreement with the SNL T3 experiment than CONTAIN - LMR. The unexpected port failure during the SNL T4 experiment presented modelling challenges. The time at which the port failure occurred is unknown, but is believed to have occur red at about 11 seconds into the sodium spray fire. The sensitivity analysis for the SNL T4 experiment shows that with a port failure, the sodium spray fire can still maintain elevated pressures during the spray.

Topography and chemoarchitecture of the striatum and pallidum in a monotreme, the short-beaked echidna (Tachyglossus aculeatus).

Science.gov (United States)

Ashwell, K W S

2008-09-01

The topography and chemoarchitecture of the striatum and pallidum in a monotreme, the short-beaked echidna (Tachyglossus aculeatus) have been studied using Nissl staining in conjunction with myelin staining, enzyme reactivity to acetylcholinesterase and NADPH diaphorase, and immunoreactivity to parvalbumin, calbindin, calretinin, tyrosine hydroxylase, neuropeptide Y, and neurofilament protein (SMI-32 antibody). All those components of the striatum and pallidum found in eutherian mammals could also be identified in the echidna's brain, with broad chemoarchitectural similarities to those regions in eutherian brains also apparent. There was a clear chemoarchitectural gradient visible with parvalbumin immunoreactivity of neurons and fibers, suggesting a subdivision of the echidna caudatoputamen into weakly reactive rostrodorsomedial and strongly reactive caudoventrolateral components. This may, in turn, relate to subdivision into associative versus sensorimotor CPu and reflect homology to the caudate and putamen of primates. Moreover, the chemoarchitecture of the echidna striatum suggested the presence of striosome-matrix architecture. The morphology of identified neuronal groups (i.e., parvalbumin, calbindin, and neuropeptide Y immunoreactive) in the echidna striatum and pallidum showed many similarities to those seen in eutherians, although the pattern of distribution of calbindin immunoreactive neurons was more uniform in the caudatoputamen of the echidna than in therians. These observations indicate that the same broad features of striatal and pallidal organization apply across all mammals and suggest that these common features may have arisen before the divergence of the monotreme and therian lineages.

Sensitive detection of Treponema pallidum DNA from the whole blood of patients with syphilis by the nested PCR assay.

Science.gov (United States)

Wang, Cuini; Cheng, Yuanyuan; Liu, Biao; Wang, Yuanyuan; Gong, Weiming; Qian, Yihong; Guan, Zhifang; Lu, Haikong; Gu, Xin; Shi, Mei; Zhou, Pingyu

2018-05-09

The aim of this work was to investigate the application of the nested PCR assay for the detection of Treponema pallidum (TP) DNA from the blood of patients with different stages of syphilis. In this study, a nested PCR method targeting the Tpp47 and polA genes (Tpp47-Tp-PCR and polA-Tp-PCR) was developed to detect TP-DNA in whole blood samples collected from 262 patients with different stages of syphilis (84 primary syphilis, 97 secondary syphilis, and 81 latent syphilis patients). The PCR assay detected T. pallidum DNA in 53.6% and 62.9% of the patients with primary and secondary syphilis, respectively, which was much higher than the detection levels in patients with latent syphilis (7.4%) (both p PCR in the early phase of the latent infection. Thus, blood RPR titers were correlated with the blood T. pallidum burden, but the correlations varied with primary and secondary syphilis. The results indicate that nested PCR is a sensitive method for detecting blood TP-DNA and is especially useful for detecting early syphilis including primary syphilis and secondary syphilis. The findings also suggest that the PCR assay may be used to complement other methods to enhance the diagnosis of syphilis.

Fire Extinguisher Training for Fire Watch and Designated Workers, Course 9893

Energy Technology Data Exchange (ETDEWEB)

Harris, Jimmy D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-04-19

At Los Alamos National Laboratory (LANL), all workers must be aware of LANL fire protection policies and be trained on what to do in the event of a fire. This course, Fire Extinguisher Training for Fire Watch and Designated Workers (#9893), provides awareness-level and hands-on training for fire watch personnel and designated workers. Fire watch personnel and designated workers are appointed by line management and must receive both awareness-level training and hands-on training in the use of portable fire extinguishers to extinguish an incipient-stage fire. This training meets the requirements of the Occupational Safety and Health Administration (OSHA) Code of Federal Regulations (CFR) 29 CFR 1910.157, Portable Fire Extinguishers, and Procedure (P) 101-26, Welding, Cutting, and Other Spark-/Flame-Producing Operations.

Fire Extinguisher Designated Worker and Fire Watch: Self-Study Course 15672

Energy Technology Data Exchange (ETDEWEB)

Harris, Jimmy D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-07-08

At Los Alamos National Laboratory (LANL), all workers must be aware of LANL fire protection policies and be trained on what to do in the event of a fire. This course, Fire Extinguisher Training for Fire Watch and Designated Workers (#9893), provides awareness-level and hands-on training for fire watch personnel and designated workers. Fire watch personnel and designated workers are appointed by line management and must receive both awareness-level training and hands-on training in the use of portable fire extinguishers to extinguish an incipient-stage fire. This training meets the requirements of the Occupational Safety and Health Administration (OSHA) Code of Federal Regulations (CFR) 29 CFR 1910.157, Portable Fire Extinguishers, and Procedure (P) 101-26, Welding, Cutting, and Other Spark-/Flame-Producing Operations.

Nuclear power plant fire protection: fire detection (subsystems study Task 2)

International Nuclear Information System (INIS)

Berry, D.L.

1977-12-01

This report examines the adequacy of fire detection in the context of nuclear power plant safety. Topics considered are: (1) establishing area detection requirements, (2) selecting specific detector types, (3) locating and spacing detectors, and (4) performing installation tests and maintenance. Based on a thorough review of fire detection codes and standards and fire detection literature, the report concludes that current design and regulatory guidelines alone are insufficient to ensure satisfactory fire detection system performance. To assure adequate fire detection, this report recommends the use of in-place testing of detectors under conditions expected to occur normally in areas being protected

Modifications made to the MELCOR Code for Analyzing Lithium Fires in Fusion Reactors

International Nuclear Information System (INIS)

Merrill, B.J.

2000-01-01

This report documents initial modifications made to the MELCOR code that allows MELCOR to predict the consequences of lithium spill accidents for evolving fusion reactor designs. These modifications include thermodynamic and transport properties for lithium, and physical models for predicting the rate of reaction of and energy production from the lithium-air reaction. A benchmarking study was performed with this new MELCOR capability. Two lithium-air reaction tests conducted at the Hanford Engineering Development Laboratory (HEDL) were selected for this benchmark study. Excellent agreement was achieved between MELCOR predictions and measured data. Recommendations for modeling lithium fires with MELCOR and for future work in this area are included in this report

Fires in large scale ventilation systems

International Nuclear Information System (INIS)

Gregory, W.S.; Martin, R.A.; White, B.W.; Nichols, B.D.; Smith, P.R.; Leslie, I.H.; Fenton, D.L.; Gunaji, M.V.; Blythe, J.P.

1991-01-01

This paper summarizes the experience gained simulating fires in large scale ventilation systems patterned after ventilation systems found in nuclear fuel cycle facilities. The series of experiments discussed included: (1) combustion aerosol loading of 0.61x0.61 m HEPA filters with the combustion products of two organic fuels, polystyrene and polymethylemethacrylate; (2) gas dynamic and heat transport through a large scale ventilation system consisting of a 0.61x0.61 m duct 90 m in length, with dampers, HEPA filters, blowers, etc.; (3) gas dynamic and simultaneous transport of heat and solid particulate (consisting of glass beads with a mean aerodynamic diameter of 10μ) through the large scale ventilation system; and (4) the transport of heat and soot, generated by kerosene pool fires, through the large scale ventilation system. The FIRAC computer code, designed to predict fire-induced transients in nuclear fuel cycle facility ventilation systems, was used to predict the results of experiments (2) through (4). In general, the results of the predictions were satisfactory. The code predictions for the gas dynamics, heat transport, and particulate transport and deposition were within 10% of the experimentally measured values. However, the code was less successful in predicting the amount of soot generation from kerosene pool fires, probably due to the fire module of the code being a one-dimensional zone model. The experiments revealed a complicated three-dimensional combustion pattern within the fire room of the ventilation system. Further refinement of the fire module within FIRAC is needed. (orig.)

The Tp0684 (MglB-2 Lipoprotein of Treponema pallidum: A Glucose-Binding Protein with Divergent Topology.

Directory of Open Access Journals (Sweden)

Chad A Brautigam

Full Text Available Treponema pallidum, the bacterium that causes syphilis, is an obligate human parasite. As such, it must acquire energy, in the form of carbon sources, from the host. There is ample evidence that the principal source of energy for this spirochete is D-glucose acquired from its environment, likely via an ABC transporter. Further, there is genetic evidence of a D-glucose chemotaxis system in T. pallidum. Both of these processes may be dependent on a single lipidated chemoreceptor: Tp0684, also called TpMglB-2 for its sequence homology to MglB of Escherichia coli. To broaden our understanding of this potentially vital protein, we determined a 2.05-Å X-ray crystal structure of a soluble form of the recombinant protein. Like its namesake, TpMglB-2 adopts a bilobed fold that is similar to that of the ligand-binding proteins (LBPs of other ABC transporters. However, the protein has an unusual, circularly permuted topology. This feature prompted a series of biophysical studies that examined whether the protein's topological distinctiveness affected its putative chemoreceptor functions. Differential scanning fluorimetry and isothermal titration calorimetry were used to confirm that the protein bound D-glucose in a cleft between its two lobes. Additionally, analytical ultracentrifugation was employed to reveal that D-glucose binding is accompanied by a significant conformational change. TpMglB-2 thus appears to be fully functional in vitro, and given the probable central importance of the protein to T. pallidum's physiology, our results have implications for the viability and pathogenicity of this obligate human pathogen.

The Tp0684 (MglB-2) Lipoprotein of Treponema pallidum: A Glucose-Binding Protein with Divergent Topology.

Science.gov (United States)

Brautigam, Chad A; Deka, Ranjit K; Liu, Wei Z; Norgard, Michael V

2016-01-01

Treponema pallidum, the bacterium that causes syphilis, is an obligate human parasite. As such, it must acquire energy, in the form of carbon sources, from the host. There is ample evidence that the principal source of energy for this spirochete is D-glucose acquired from its environment, likely via an ABC transporter. Further, there is genetic evidence of a D-glucose chemotaxis system in T. pallidum. Both of these processes may be dependent on a single lipidated chemoreceptor: Tp0684, also called TpMglB-2 for its sequence homology to MglB of Escherichia coli. To broaden our understanding of this potentially vital protein, we determined a 2.05-Å X-ray crystal structure of a soluble form of the recombinant protein. Like its namesake, TpMglB-2 adopts a bilobed fold that is similar to that of the ligand-binding proteins (LBPs) of other ABC transporters. However, the protein has an unusual, circularly permuted topology. This feature prompted a series of biophysical studies that examined whether the protein's topological distinctiveness affected its putative chemoreceptor functions. Differential scanning fluorimetry and isothermal titration calorimetry were used to confirm that the protein bound D-glucose in a cleft between its two lobes. Additionally, analytical ultracentrifugation was employed to reveal that D-glucose binding is accompanied by a significant conformational change. TpMglB-2 thus appears to be fully functional in vitro, and given the probable central importance of the protein to T. pallidum's physiology, our results have implications for the viability and pathogenicity of this obligate human pathogen.

DOE Standard: Fire protection design criteria

International Nuclear Information System (INIS)

1999-07-01

The development of this Standard reflects the fact that national consensus standards and other design criteria do not comprehensively or, in some cases, adequately address fire protection issues at DOE facilities. This Standard provides supplemental fire protection guidance applicable to the design and construction of DOE facilities and site features (such as water distribution systems) that are also provided for fire protection. It is intended to be used in conjunction with the applicable building code, National Fire Protection Association (NFPA) Codes and Standards, and any other applicable DOE construction criteria. This Standard replaces certain mandatory fire protection requirements that were formerly in DOE 5480.7A, ''Fire Protection'', and DOE 6430.1A, ''General Design Criteria''. It also contains the fire protection guidelines from two (now canceled) draft standards: ''Glove Box Fire Protection'' and ''Filter Plenum Fire Protection''. (Note: This Standard does not supersede the requirements of DOE 5480.7A and DOE 6430.1A where these DOE Orders are currently applicable under existing contracts.) This Standard, along with the criteria delineated in Section 3, constitutes the basic criteria for satisfying DOE fire and life safety objectives for the design and construction or renovation of DOE facilities

Fire risk assessment method under the technical building code; Metodo de evaluacion del reisgo de incendio en el marco del Codigo Tecnico de la Edificacion

Energy Technology Data Exchange (ETDEWEB)

Perez-Martin, J. C.; Diaz-Diaz, R.; Santos-Garcia, R.

2010-07-01

The high complexity of measuring and comparing the risk level of performance based design allowed by the Spain Building Code (CTE) and the lack of Spanish legislation on the matter makes a fire risk evaluation tool highly useful guiding the project's and the control authority over the feasibility of these complicated projects. A fire Risk Evaluation Method within the frame of the Spanish Building Code (MEREDICTE) has been developed trying to balance input sources, simplicity and clearness in its use. The number of parameters implied guarantees sound, exhaustive and reliable outputs. MEREDICTE is made of 73 parameters: 31 calculate potential risk and 42 obtain protection level. In an orientative way, MEREDICTE's parameters triple those of the most referred and extended evaluation method: the Gretener Method. The article shows the MEREDICTE technique and foundations, the methodology used in its investigation and development, its most significant innovation and its possible applications. Regarding the protection level, its formulation and applications re referred to the Windsor buildings of Madrid comparing the results obtained on the building as it was devastated by the fire of February 2005 and whether it fulfilled the Spanish building code conditions. (Author) 8 refs.

Evaluation of the HISCL Anti-Treponema pallidum Assay as a Screening Test for Syphilis.

Science.gov (United States)

An, Jingna; Chen, Qixia; Liu, Qianqian; Rao, Chenli; Li, Dongdong; Wang, Tingting; Tao, Chuanmin; Wang, Lanlan

2015-07-01

The resurgence of syphilis in recent years has become a serious threat to public health worldwide, and the serological detection of specific antibodies against Treponema pallidum remains the most reliable method for laboratory diagnosis of syphilis. This study examined the performance of the recently launched HISCL anti-Treponema pallidum (anti-TP) assay as a screening test for syphilis in a high-volume laboratory. The HISCL anti-TP assay was tested in 300 preselected syphilis-positive samples, 704 fresh syphilis-negative samples, 48 preselected potentially interfering samples, and 30 "borderline" samples and was compared head to head with the commercially available Lumipulse G TP-N. In this study, the HISCL anti-TP assay was in perfect agreement with the applied testing algorithms with an overall agreement of 100%, comparable to that of Lumipulse G TP-N (99.63%). The sensitivity and specificity of the HISCL anti-TP assay were 100% (95% confidence interval [CI], 98.42% to 100%) and 100% (95% CI, 99.37% to 100%), respectively. Considering the excellent ease of use and automation, high throughput, and its favorable sensitivity and specificity, the HISCL anti-TP assay may represent a new choice for syphilis screening in high-volume laboratories. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Alternative approach for fire suppression of class A, B and C fires in gloveboxes

Energy Technology Data Exchange (ETDEWEB)

Rosenberger, Mark S [Los Alamos National Laboratory; Tsiagkouris, James A [Los Alamos National Laboratory

2011-02-10

Department of Energy (DOE) Orders and National Fire Protection Association (NFPA) Codes and Standards require fire suppression in gloveboxes. Several potential solutions have been and are currently being considered at Los Alamos National Laboratory (LANL). The objective is to provide reliable, minimally invasive, and seismically robust fire suppression capable of extinguishing Class A, B, and C fires; achieve compliance with DOE and NFPA requirements; and provide value-added improvements to fire safety in gloveboxes. This report provides a brief summary of current approaches and also documents the successful fire tests conducted to prove that one approach, specifically Fire Foe{trademark} tubes, is capable of achieving the requirement to provide reliable fire protection in gloveboxes in a cost-effective manner.

Response of fire detectors to different smokes

International Nuclear Information System (INIS)

Bjoerkman, J.; Keski-Rahkonen, O.

1997-01-01

The purpose of this work is to characterize the behavior of fire alarm systems based on smoke detectors on smoldering fires especially cable fires in nuclear power plants (NPP). Full-scale fire experiments were carried out in a laboratory designed according to the standard EN54-9. The laboratory was instrumented with additional equipment such as thermocouples and flow meters which are not used in standard fire sensitivity tests. This allows the results to be used as experimental data for validation tasks of numerical fire simulation computerized fluid dynamics (CFD)-codes. The ultimate goal of the research is to model theoretically smoldering and flaming cable fires, their smoke production, transfer of smoke to detectors, as well as the response of detectors and fire alarm systems to potential fires. This would allow the use of numerical fire simulation to predict fire hazards in different fire scenarios found important in PSA (probability safety assessment) of NPPs. This report concentrates on explaining full-scale fire experiments in the smoke sensitivity laboratory and experimental results from fire tests of detectors. Validation tasks with CFD-codes will be first carried out 'blind' without any idea about corresponding experimental results. Accordingly, the experimental results cannot be published in this report. (orig.)

Calculations detailed progression of fire in NPP ALMARAZ through the code computational fire dynamics SIMULATOR

International Nuclear Information System (INIS)

Villar Sanchez, T.

2012-01-01

(FDS) is an advanced computational model of calculation of simulation of fire that numerically solves the Navier-Stokes equations in each cell of the mesh in each interval of time, having capacity to calculate accurately all those parameters of fire to NUREG-1805 has a limited capacity. The objective of the analysis is to compare the results obtained with the FDS with those obtained from spreadsheets of NUREG-1805 and deal widespread and realistic study of the propagation of a fire in different areas of NPP Almaraz.

Development of the CELVA-1D code to evaluate the safety of an air-ventilation system during postulated fire and explosion in the reprocessing plant. Contract research

International Nuclear Information System (INIS)

Nishio, Gunji; Watanabe, Kouji; Kouno, Kouji; Yamazaki, Noboru; Mukaide, Shigeo; Yoshioka, Itsuo

1998-03-01

The CELVA-1D computer code was developed to evaluate the confinement of radioactive materials during postulated fire and explosion in a cell of nuclear fuel reprocessing plants. The CELVA-1D code calculates a response of temperature, pressure, flow velocity of fluid in an air-ventilation system of the plants by one-dimensional thermofluid analysis and calculates an ability to confine radioactive aerosol particles by transport, deposition, and HEPA filtration. The mathematical models in CELVA-1D were verified by comparison of the calculation with the result of JAERI's demonstration tests simulating hypothetical fire and explosion accidents in the cell. (author)

Development of the CELVA-1D code to evaluate the safety of an air-ventilation system during postulated fire and explosion in the reprocessing plant. Contract research

Energy Technology Data Exchange (ETDEWEB)

Nishio, Gunji; Watanabe, Kouji [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kouno, Kouji; Yamazaki, Noboru; Mukaide, Shigeo; Yoshioka, Itsuo

1998-03-01

The CELVA-1D computer code was developed to evaluate the confinement of radioactive materials during postulated fire and explosion in a cell of nuclear fuel reprocessing plants. The CELVA-1D code calculates a response of temperature, pressure, flow velocity of fluid in an air-ventilation system of the plants by one-dimensional thermofluid analysis and calculates an ability to confine radioactive aerosol particles by transport, deposition, and HEPA filtration. The mathematical models in CELVA-1D were verified by comparison of the calculation with the result of JAERI`s demonstration tests simulating hypothetical fire and explosion accidents in the cell. (author)

Extension of the code COCOSYS to a dispersion code for smoke and carbon monoxide

International Nuclear Information System (INIS)

Sdouz, Gert; Mayrhofer, Robert

2009-01-01

The code COCOSYS (Containment Code SYStem) was developed by GRS in Germany to simulate processes and nuclear plant states during severe accidents in the containments of light water reactors. It contains several physical models, especially a module for aerosol behaviour. The goal of this work was to extend COCOSYS for applications in more general geometries mainly for complex public buildings. For the application in public buildings models for air condition systems and different boundary conditions according to different environments were developed. The principal application of the extended code COCOSYS is in the area of emergency situations especially in the simulation for carbon monoxide and smoke dispersion. After developing and implementing the new models several test calculations were performed to evaluate the functionality of the extended code. The comparison of the results with those of the original COCOSYS code showed no discrepancies. For the first realistic application several fire emergency scenarios in the Vienna General Hospital (AKH) were selected in agreement with the fire department of the hospital. One of the scenarios addresses the danger of carbon monoxide (CO) and smoke leaking into a fire protection section through a damaged fire protection flap. As a result of the dispersion simulation the CO-concentration in all of the rooms is obtained. Together with additional results as deposition and smoke dispersion the outcome of the simulation can be used for training. Among the next steps are the validation of the new models and the selection of critical scenarios. (author)

Advanced methods for a probabilistic safety analysis of fires. Development of advanced methods for performing as far as possible realistic plant specific fire risk analysis (fire PSA)

International Nuclear Information System (INIS)

Hofer, E.; Roewekamp, M.; Tuerschmann, M.

2003-07-01

In the frame of the research project RS 1112 'Development of Methods for a Recent Probabilistic Safety Analysis, Particularly Level 2' funded by the German Federal Ministry of Economics and Technology (BMWi), advanced methods, in particular for performing as far as possible realistic plant specific fire risk analyses (fire PSA), should be developed. The present Technical Report gives an overview on the methodologies developed in this context for assessing the fire hazard. In the context of developing advanced methodologies for fire PSA, a probabilistic dynamics analysis with a fire simulation code including an uncertainty and sensitivity study has been performed for an exemplary scenario of a cable fire induced by an electric cabinet inside the containment of a modern Konvoi type German nuclear power plant taking into consideration the effects of fire detection and fire extinguishing means. With the present study, it was possible for the first time to determine the probabilities of specified fire effects from a class of fire events by means of probabilistic dynamics supplemented by uncertainty and sensitivity analyses. The analysis applies a deterministic dynamics model, consisting of a dynamic fire simulation code and a model of countermeasures, considering effects of the stochastics (so-called aleatory uncertainties) as well as uncertainties in the state of knowledge (so-called epistemic uncertainties). By this means, probability assessments including uncertainties are provided to be used within the PSA. (orig.) [de

EPS insulated façade fires from a fire and rescue perspective

Directory of Open Access Journals (Sweden)

Kumm M.

2013-11-01

Full Text Available This paper highlights the challenges the fire and rescue services can meet at façade fires involving EPS insulation during construction and use of a building. The EPS characteristics are discussed in respect to the fire and rescue operation and results from orientating fire tests performed at a fire and rescue services training and test field are presented. Types of evacuation solutions, involving the fire and rescue services, where façade fires can delay or completely rule out the possibilities for safe evacuation, are presented. The restrictions in the Swedish building codes regarding use of combustible insulation are analysed and reflections over the practical problems with following the instructions to keep an EPS insulated façade safe through the building's whole lifespan are made. A number of occurred fires involving EPS are discussed and analysed from a fire and rescue perspective. Finally, recommendations are given for the fire and rescue services and future research fields are proposed.

Investigations concerning fire-induced accidents in nuclear facilities

International Nuclear Information System (INIS)

Lamuth, P.; Lernout, L.A.; Bonneval, F.; Cottaz, M.

1996-01-01

In the context of fire protection in technical buildings of French nuclear facilities, three principles have been adopted: prevention, detection and fire-fighting. Their implementation makes it possible on the one hand to limit the fire ignition and the fire growth, and on the other hand to prevent fire extent which would lead to unavailability of several safety related equipment. Although progress has been made in this direction, the fire risks have still not been eliminated. It is therefore essential to evaluate the fire effects and to assess their consequences. To this end, three main R and D programs have been conducted into fires. Part I sets out the fire PSA methodology used for a 900 MWe PWR. Part II gives an outline of two fire and ventilation computer codes useful for the fire PSA. Finally, part III gives an outline of the tests already performed and those currently under way in the two laboratories of the Institut de Protection et de Surete Nucleaire (IPSN) in order to qualify the codes and provide useful information for the safety assessment. (author)

Lab Fire Extinguishers: Here Today, Gone Tomorrow?

Science.gov (United States)

Roy, Ken

2010-01-01

When renovations or new construction occur, fire extinguishers sometimes get lost in the mix. Unfortunately, whether to save money or because the fire code is misinterpreted, some schools do not install fire extinguishers in laboratories and other areas of the building. Let's set the record straight! If flammables are present, the fire code…

Modelling of fire spread in car parks

NARCIS (Netherlands)

Noordijk, L.M.; Lemaire, A.D.

2005-01-01

Currently, design codes assume that in a car park fire at most 3-4 vehicles are on fire at the same time. Recent incidents in car parks have drawn international attention to such assumptions and have raised questions as to the fire spreading mechanism and the resulting fire load on the structure.

CONCEPT computer code

International Nuclear Information System (INIS)

Delene, J.

1984-01-01

CONCEPT is a computer code that will provide conceptual capital investment cost estimates for nuclear and coal-fired power plants. The code can develop an estimate for construction at any point in time. Any unit size within the range of about 400 to 1300 MW electric may be selected. Any of 23 reference site locations across the United States and Canada may be selected. PWR, BWR, and coal-fired plants burning high-sulfur and low-sulfur coal can be estimated. Multiple-unit plants can be estimated. Costs due to escalation/inflation and interest during construction are calculated

Comparison of a Recombinant-antigen Enzyme Immunoassay with Treponema pallidum Hemagglutination Test for Serological Confirmation of Syphilis

Directory of Open Access Journals (Sweden)

Rodríguez Islay

2002-01-01

Full Text Available A recombinant-antigen enzyme immunoassay (EIA, BioSCREEN TM anti-Treponema pallidum, was compared favorably with the T. pallidum hemagglutination test, in the detection of specific antibodies in different groups of sera from patients with primary (n = 38, secondary (n = 10, early latent (n = 28 and congenital syphilis (n = 2, patients with leptospirosis ( n= 8, infectious mononucleosis (n = 7, hepatitis (n = 9, diabetes mellitus (n = 11, rheumatoid arthritis (n = 13, leprosy (n = 11, tuberculosis (n = 9, HIV/Aids ( n= 12, systemic lupus erythematosus (n = 4, rheumatic fever (n = 3, old-persons (n = 9, pregnant women (n = 29 and blood donors (n = 164. The coincidence between them was 95.1%. The sensitivity and specificity of the EIA were 93.3% and 95.5%, respectively. Fifteen serum specimens belonging to old-persons, pregnant women, blood donors, and patients with human leptospirosis, hepatitis, diabetes mellitus, tuberculosis and rheumatic fever gave false-positive results by Venereal Disease Research Laboratory and/or Rapid Plasma Reagin. The EIA can be used as alternative method for the serological confirmation of syphilis.

acme: The Amendable Coal-Fire Modeling Exercise. A C++ Class Library for the Numerical Simulation of Coal-Fires

Science.gov (United States)

Wuttke, Manfred W.

2017-04-01

At LIAG, we use numerical models to develop and enhance understanding of coupled transport processes and to predict the dynamics of the system under consideration. Topics include geothermal heat utilization, subrosion processes, and spontaneous underground coal fires. Although the details make it inconvenient if not impossible to apply a single code implementation to all systems, their investigations go along similar paths: They all depend on the solution of coupled transport equations. We thus saw a need for a modular code system with open access for the various communities to maximize the shared synergistic effects. To this purpose we develop the oops! ( open object-oriented parallel solutions) - toolkit, a C++ class library for the numerical solution of mathematical models of coupled thermal, hydraulic and chemical processes. This is used to develop problem-specific libraries like acme( amendable coal-fire modeling exercise), a class library for the numerical simulation of coal-fires and applications like kobra (Kohlebrand, german for coal-fire), a numerical simulation code for standard coal-fire models. Basic principle of the oops!-code system is the provision of data types for the description of space and time dependent data fields, description of terms of partial differential equations (pde), their discretisation and solving methods. Coupling of different processes, described by their particular pde is modeled by an automatic timescale-ordered operator-splitting technique. acme is a derived coal-fire specific application library, depending on oops!. If specific functionalities of general interest are implemented and have been tested they will be assimilated into the main oops!-library. Interfaces to external pre- and post-processing tools are easily implemented. Thus a construction kit which can be arbitrarily amended is formed. With the kobra-application constructed with acme we study the processes and propagation of shallow coal seam fires in particular in

Fire environment determination in the LaSalle NPP control room

Energy Technology Data Exchange (ETDEWEB)

Usher, J.L.; Boccio, J.L.; Singhal, A.K.; Tam, L.T.

1986-01-01

One objective of NRC's Fire Protection Research Program (FPRP) is to improve the modeling of environments caused by fires in typical nuclear power plant enclosures. A three-dimensional fluid dynamics computer code (PHOENICS) has been adapted as a field-model fire code (SAFFIRE) for this purpose. The model has been applied to simulate two distinct fires in the control room of the LaSalle County power plant. The environments determined illustrate hazardous potential for both personnel and equipment.

Building Codes and Regulations.

Science.gov (United States)

Fisher, John L.

The hazard of fire is of great concern to libraries due to combustible books and new plastics used in construction and interiors. Building codes and standards can offer architects and planners guidelines to follow but these standards should be closely monitored, updated, and researched for fire prevention. (DS)

Determination by a CFD code of the heat release rate in a confined and mechanically-ventilated compartment fire

International Nuclear Information System (INIS)

Nasr, Ayoub

2011-01-01

For several years, many experimental/numerical research programs have been carried out at IRSN in order to provide sufficient data on the burning process and understand the behavior of a pool fire in a confined and mechanically ventilated compartment. Several experimental tests have shown that in some cases, the oxygen concentration in the local decreases then stabilizes until fire extinction. The fuel mass loss rate is instantaneously adjusted according to the ventilation in the local, which may leads to a lower fuel consumption rate as compared to that in free atmosphere. The fire duration is then 2 to 3 times greater than that obtained in free atmosphere, which may damages some specific safety equipment used to reduce the spread of fire between compartments such as fire doors. The objective of this work is to propose a theoretical approach that allows the determination of the burning rate of fuels for pool fires in a closed compartment. Fuel response to vitiated air as well as burning enhancement due to hot gases and confinement should be taken into account. Thus, a theoretical formulation, based on an energy balance equation at the pool fire surface, was developed and compared with the empirical correlation of Peatross and Beyler before being implemented in a CFD code 'ISIS', developed at IRSN and validated against PRISME fire test results. The main advantage of this global approach is that no assumptions were made on the relative importance of each mode of heat transfer from the flame. In fact, the convective and the radiant components of the heat flux from the flame to the fuel surface were determined taking into account the air vitiation effect. In addition to this theoretical approach, an experimental work was conducted at the Institut PPRIME to study heptane pool fires in a reduced-scale fire compartment, in the aim to investigate the effects of vitiated air on fire parameters. These results were used to validate the theoretical formulation developed

Fire Technology Abstracts, volume 4, issue 1, August, 1981

Science.gov (United States)

Holtschlag, L. J.; Kuvshinoff, B. W.; Jernigan, J. B.

This bibliography contains over 400 citations with abstracts addressing various aspects of fire technology. Subjects cover the dynamics of fire, behavior and properties of materials, fire modeling and test burns, fire protection, fire safety, fire service organization, apparatus and equipment, fire prevention, suppression, planning, human behavior, medical problems, codes and standards, hazard identification, safe handling of materials, insurance, economics of loss and prevention, and more.

The use of CAFE-3D for the simulation of tunnel fires

Energy Technology Data Exchange (ETDEWEB)

Lopez, C.; Koski, J.A.; Hohnstreiter, G.F.; Khalil, I. [Sandia National Labs., Albuquerque, NM (United States); Suo-Anttila, A. [Alion Science and Technology, Albuquerque, NM (United States)

2004-07-01

Fires after accidents inside tunnels, such as the July 2001 Howard Street Tunnel fire in Baltimore, Maryland, USA, have raised stakeholder questions concerning the survivability of a spent nuclear fuel (SNF) transport cask when exposed to similar thermal environments. The analysis of tunnel fires is a computational challenge because of the need for very large computational domains in order to fully simulate such a problem. In this paper, the analyses of two different tunnel fire scenarios are described and the performance of typical SNF casks when exposed to these tunnel fire environments is discussed. The CAFE-3D fire code is used to model a series of fires inside tunnels, and the thermal performance of a SNF transportation cask within such fire environments is estimated with the use of the MSC PATRAN-P/Thermal finite element analysis code. The methodology used to simulate this type of fire scenario as well as a description of the manner in which the CAFE code couples the computational fluid dynamics and the finite element analysis techniques are also presented.

The use of CAFE-3D for the simulation of tunnel fires

International Nuclear Information System (INIS)

Lopez, C.; Koski, J.A.; Hohnstreiter, G.F.; Khalil, I.; Suo-Anttila, A.

2004-01-01

Fires after accidents inside tunnels, such as the July 2001 Howard Street Tunnel fire in Baltimore, Maryland, USA, have raised stakeholder questions concerning the survivability of a spent nuclear fuel (SNF) transport cask when exposed to similar thermal environments. The analysis of tunnel fires is a computational challenge because of the need for very large computational domains in order to fully simulate such a problem. In this paper, the analyses of two different tunnel fire scenarios are described and the performance of typical SNF casks when exposed to these tunnel fire environments is discussed. The CAFE-3D fire code is used to model a series of fires inside tunnels, and the thermal performance of a SNF transportation cask within such fire environments is estimated with the use of the MSC PATRAN-P/Thermal finite element analysis code. The methodology used to simulate this type of fire scenario as well as a description of the manner in which the CAFE code couples the computational fluid dynamics and the finite element analysis techniques are also presented

FIRE PERMIT NOW ON EDH!

CERN Multimedia

TIS General Safety Group or

2001-01-01

The electronic version of the Fire Permit form is now active. The aim of the Fire Permit procedure is to reduce the risk of fire or explosion. It is mandatory when performing 'hot work' (mainly activities which involve the use of naked flames or other heat sources - e.g. welding, brazing, cutting, grinding, etc.). Its use is explained in the CERN Fire Protection Code E. (Fire Protection) The new electronic form, which is substantially unchanged from the previous authorizing procedure, will be available on the Electronic Document Handling system (https://edh.cern.ch/) as of 1st September 2001. From this date use of the paper version should be discontinued.

Using satellite fire detection to calibrate components of the fire weather index system in Malaysia and Indonesia.

Science.gov (United States)

Dymond, Caren C; Field, Robert D; Roswintiarti, Orbita; Guswanto

2005-04-01

Vegetation fires have become an increasing problem in tropical environments as a consequence of socioeconomic pressures and subsequent land-use change. In response, fire management systems are being developed. This study set out to determine the relationships between two aspects of the fire problems in western Indonesia and Malaysia, and two components of the Canadian Forest Fire Weather Index System. The study resulted in a new method for calibrating components of fire danger rating systems based on satellite fire detection (hotspot) data. Once the climate was accounted for, a problematic number of fires were related to high levels of the Fine Fuel Moisture Code. The relationship between climate, Fine Fuel Moisture Code, and hotspot occurrence was used to calibrate Fire Occurrence Potential classes where low accounted for 3% of the fires from 1994 to 2000, moderate accounted for 25%, high 26%, and extreme 38%. Further problems arise when there are large clusters of fires burning that may consume valuable land or produce local smoke pollution. Once the climate was taken into account, the hotspot load (number and size of clusters of hotspots) was related to the Fire Weather Index. The relationship between climate, Fire Weather Index, and hotspot load was used to calibrate Fire Load Potential classes. Low Fire Load Potential conditions (75% of an average year) corresponded with 24% of the hotspot clusters, which had an average size of 30% of the largest cluster. In contrast, extreme Fire Load Potential conditions (1% of an average year) corresponded with 30% of the hotspot clusters, which had an average size of 58% of the maximum. Both Fire Occurrence Potential and Fire Load Potential calibrations were successfully validated with data from 2001. This study showed that when ground measurements are not available, fire statistics derived from satellite fire detection archives can be reliably used for calibration. More importantly, as a result of this work, Malaysia and

Literature study regarding fire protection in nuclear power plants. Part I: Fire rated separations

International Nuclear Information System (INIS)

Isaksson, S.

1995-06-01

This literature study has been made on behalf of the Swedish Nuclear Power Inspectorate. The aim is to describe different aspects of fire protection in nuclear power plants. Conventional building codes can not give guidance on where to make fire rated separations in order to separate redundant trains of safety systems. The separation must originate in functional demands from the authorities on what functions are essential during and after a fire, and under what circumstances these functions shall be retained, i.e. the number of independent faults and initiating events. As a basic demand it is suggested to rate the strength of separations according to conventional building code, based on fire load. The whole separating construction shall have the same fire rating, including the ventilation system. Deviations from the basic demand can de done in case it can be proven that it is possible to compensate some or all of the fire rating with other measures. There is a general lack of statistical information regarding the reliability of fire separating constructions such as walls, fire doors, penetration seals and fire dampers. The amount of cables penetrating a seal is in many cases much higher in real installations than what has been tested for type approval. It would therefore be valuable to perform a furnace test with a more representative amount of cables passing through a penetration seal. Tests have shown that the 20 foot horizontal separation distance stipulated by NRC is not a guarantee against fire damage. Spatial separations based on general requirements shall not be allowed, but considered from case to case based on actual circumstances. For fire protection by isolation or coatings, it is of great importance to choose the method of protection carefully, to be compatible with the material it shall be applied on, and the environment and types of fire that may occur. 48 refs, 2 figs, 5 tabs

Molecular typing of Treponema pallidum isolates from Buenos Aires, Argentina: Frequent Nichols-like isolates and low levels of macrolide resistance.

Directory of Open Access Journals (Sweden)

Lucía Gallo Vaulet

Full Text Available A total of 54 clinical samples, including genital lesion swabs, whole blood and cerebrospinal fluid from patients diagnosed with syphilis were collected in 2006 and in 2013 in Buenos Aires, Argentina. Treponemal DNA was detected in 43 of the analyzed samples (79.6% and further analyzed using Sequencing-based molecular typing (SBMT and Enhanced CDC-typing (ECDCT. By SBMT, 10 different Treponema pallidum subsp. pallidum (TPA genotypes were found, of which six were related to the TPA SS14 strain, and four to the TPA Nichols strain. The 23S rRNA gene was amplified in samples isolated from 42 patients, and in six of them (14.3%, either the A2058G (four patients, 9.5% or the A2059G (two patients, 4.8% mutations were found. In addition to Taiwan, Madagascar and Peru, Argentina is another country where the prevalence of Nichols-like isolates (26.8% is greater than 10%.

Maintenance of fire systems and equipment at Virginia Power

International Nuclear Information System (INIS)

Doubrely, E.B. Jr.

1989-01-01

The basics of fire protection systems maintenance are well codified and documented in the National Fire Codes published by the National Fire Protection Association. In addition, Insurers often promulgate minimum standards for fire protection systems design and maintenance to which they attach conditions of insurability. Regulatory agencies and even in-house corporate policies can impact the maintenance of fire protection systems and equipment. This presentation will focus on the various methods and alternate ways of performing system maintenance, whether required by code, insurer, or by some regulatory commitment at Virginia Powers North Anna and Surry nuclear power stations. The approach to performing similar work is handled differently at each station. This difference can be attributed to proximity to outside assistance as well as plant philosophy. In addition to station maintenance practices, a discussion of in-house servicing of portable fire suppression equipment is offered. 1 tab

24 CFR 200.925c - Model codes.

Science.gov (United States)

2010-04-01

... below. (1) Model Building Codes—(i) The BOCA National Building Code, 1993 Edition, The BOCA National..., Administration, for the Building, Plumbing and Mechanical Codes and the references to fire retardant treated wood... number 2 (Chapter 7) of the Building Code, but including the Appendices of the Code. Available from...

Probabilistic assessment of fire related events in CWPH (Pilot study)

International Nuclear Information System (INIS)

Chatterjee, D.; Maity, S.C.; Guptan, Rajee; Mohan, Nalini; Ghadge, S.G.; Bajaj, S.S.

2006-01-01

As a part of Fire PSA for KAPS, a pilot study has been taken up identifying CWPH as the important zone vulnerable to fire. As the CWPH houses pumps belonging to all important cooling (APWC, FFW, NAHPPW, NALPW, etc.) of both the units, a single fire leads to failure of multiple safety/safety support system cooling affecting the safety of the plant. The objective of this study is as follows: Familiarising with the various published Fire-PSA study, comparing and finalisation of the computer code amongst various codes available with DAE, identifying and sequencing different activities involved for carrying out Fire PSA, i.e. Zoning and Sub-Zoning of Fire Source Area, Fire vulnerability of System and Component surrounding Fire Source, etc., finalization of report format and documentation. Computer Code FDS is used to carry out Fire Hazard Analysis. FDS is the latest state-of the-art software package extensively used for Fire Hazard Analysis. It develops a 3D scenario for any given fire giving credit to actual physical location of fire load and ventilation. It gives the time dependent of any fire in a specific zone crediting the time required by operator to take necessary preventive action which helps in quantifying the probability of error for any particular operator's for PSA study. To identify the most vulnerable sub-zone in CWPH, a walk down was organized and physical location of each load; their separation, fire barrier, ventilator in the room, arrangement of fire protection/fighting system, localized operator's room were reviewed. Fire in the middle diesel tank with pump is considered as initiating event in the sub-zone of CWPH. The Event Tree for this initiating event for CWPH was developed. Event Tree end states are identified as large fire i.e. fire which is failed to be detected by both means, i.e. early and late and failure in fighting by both means i.e. early and late. (author)

Modeling of compartment fire

International Nuclear Information System (INIS)

Sathiah, P.; Siccama, A.; Visser, D.; Komen, E.

2011-01-01

Fire accident in a containment is a serious threat to nuclear reactors. Fire can cause substantial loss to life and property. The risk posed by fire can also exceed the risk from internal events within a nuclear reactor. Numerous research efforts have been performed to understand and analyze the phenomenon of fire in nuclear reactor and its consequences. Modeling of fire is an important subject in the field of fire safety engineering. Two approaches which are commonly used in fire modeling are zonal modeling and field modeling. The objective of this work is to compare zonal and field modeling approach against a pool fired experiment performed in a well-confined compartment. Numerical simulations were performed against experiments, which were conducted within PRISME program under the framework of OECD. In these experiments, effects of ventilation flow rate on heat release rate in a confined and mechanically ventilated compartment is investigated. Time dependent changes in gas temperature and oxygen mass fraction were measured. The trends obtained by numerical simulation performed using zonal model and field model compares well with experiments. Further validation is needed before this code can be used for fire safety analyses. (author)

Ignition and combustion of sodium, fire consequences, extinguishment and prevention

International Nuclear Information System (INIS)

Malet, J.C.

1996-01-01

This document presents the results of work carried out at the IPSN on: sodium inflammation, sodium combustion (pool fires and sprayed jet fires), extinguishment (passive means and extinguishing powder), the physico-chemical behaviour of aerosols and their filtration, the protection means of concretes, intervention during and after a fire, treatment of residues, intervention equipment. The calculation codes developed during these studies are described. The experimental basis which allowed the qualification of these codes and the technological means aimed at prevention and sodium fire fighting, was obtained using programmes carried out in the experimental facilities existing in Cadarache or in collaboration with the German teams of Karlsruhe

Ignition and combustion of sodium, fire consequences, extinguishment and prevention

Energy Technology Data Exchange (ETDEWEB)

Malet, J C [Institut de Protection et de Surete Nucleaire, Laboratoire d' Experimentation de Modelisation des Feux, C.E. Cadarache, Saint-Paul-lez-Durance (France). E-mail: malet at ipsncad.cea.fr

1996-07-01

This document presents the results of work carried out at the IPSN on: sodium inflammation, sodium combustion (pool fires and sprayed jet fires), extinguishment (passive means and extinguishing powder), the physico-chemical behaviour of aerosols and their filtration, the protection means of concretes, intervention during and after a fire, treatment of residues, intervention equipment. The calculation codes developed during these studies are described. The experimental basis which allowed the qualification of these codes and the technological means aimed at prevention and sodium fire fighting, was obtained using programmes carried out in the experimental facilities existing in Cadarache or in collaboration with the German teams of Karlsruhe.

Sodium fires at fast reactors: RF status report

International Nuclear Information System (INIS)

Bagdasarov, Yu.E.; Buksha, Yu.K.; Drobyshev, A.V.; Zybin, V.A.; Ivanenko, V.N.; Kardash, D.Yu.; Kulikov, E.V.; Yagodkin, I.V.

1996-01-01

Scientific and engineering studies carried out in Russian Federation since 1992 up to 1996 in the sodium fire area and their main results are described. A review of activities on modification of the computer codes BOX and AERO developed at IPPE for calculating sodium fire consequences is given. Results of analysis of possible accidental situations at currently designed BN-800 reactor NPP with the use of these codes are presented. Sodium leaks occurring at our domestic fast reactors are briefly analyzed. Experimental work performed are described. Results of comparative analysis of common-cause and sodium fire hazards for fast reactor NPP are presented. (author)

Fire Pumps: Time to Change NFPA 25 Weekly Churn Testing

Science.gov (United States)

Saidi, John F.; Davis, Richard J.

2010-01-01

APPA, through its Code Advocacy Task Force (CATF), is active with code organizations such as the National Fire Protection Association (NFPA). This article reviews some of the recent work on NFPA 25, Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, by the CATF and some members of the NFPA 25 Technical…

U.S. position paper on sodium fires, design and testing

International Nuclear Information System (INIS)

Hilliard, R.K.; Johnson, R.P.; Powers, D.A.

1982-05-01

Sodium combustion phenomena and U.S. computer codes developed for sodium fires are discussed. Ways of preventing and mitigating sodium fires are described. Effects of sodium fires and spills on LMFBR structural materials, thermal insulation materials, and equipment/instrumentation are considered

Safety guide on fire protection in nuclear power plants

International Nuclear Information System (INIS)

1976-01-01

The purpose of the Safety Guide is to give specific design and operational guidance for protection from fire and explosion in nuclear power plants, based on the general guidance given in the relevant sections of the 'Safety Code of Practice - Design' and the 'Safety Code of Practice - Operation' of the International Atomic Energy Agency. The guide will confine itself to fire protection of safety systems and items important to safety, leaving the non-safety matters of fire protection in nuclear power plants to be decided upon the basis of the various available national and international practices and regulations. (HP) [de

Evaluation of the influence of a postulated lubrication oil fire on safety related cables in the top shield platform of PFBR RCB by using FDS Code

International Nuclear Information System (INIS)

Mangarjuna Rao, P.; Jayasuriya, C.; Nashine, B.K.; Chellapandi, P.; Velusamy, K.

2010-01-01

Top deck of Prototype Fast Breeder Reactor (PFBR) primary system houses redundant safety related systems like Control and Safety Rod Drive Mechanisms (CSRDM), Diverse Safety Rod Drive Mechanism (DSRDM), subassembly outlet sodium temperature measurement system and central canal plug. These systems protrude out from the reactor through the Control Plug (CP), which is supported on the Top Shield (TS) of PFBR. Control and instrumentation signal cables and power cables of these safety related systems that are coming out from the CP are routed through Top Shield Platform (TSP, which is concentric with Reactor Vault (RV) at EL 34.1 m above the TS) to the peripheral local instrumentation control centers via the cable junction boxes supported on TS. Influence approach fire hazard analysis (FHA) has been carried out to evaluate the condition of redundant safety related cables under the scenario of a postulated oil fire in the TSP using Fire Dynamics Simulator code (FDS, Version 5). FDS is a computational fluid dynamics (CFD) based fire analysis code and it is developed by National Institute of Standards and Technology (NIST), USA. In this paper the details of the model developed and the results of the analysis carried out are discussed. In TSP, a postulated oil fire scenario with complete inventory of a primary sodium pump (PSP) lubrication oil leak (200 lt) has been considered at 30 m elevation on the TS. Computational model with the geometry of TSP and with other important structural components on TS like PSPs, intermediate heat exchangers (IHXs), large rotating plug (LRP), small rotating plug (SRP), CP and etc. has been developed along with a fire of 1800 kW/m 2 heat release rate in the vicinity of the PSP1. Numerical simulation has been carried out to evaluate this oil fire influence on the typical safety related cables routed at 34 m elevation. It has been found that the surface temperature of the cables that are routed directly above the fire only crosses the ignition

Evaluation of fire models for nuclear power plant applications. Benchmark exercise no. 4: Fuel pool fire inside a compartment - International panel report

International Nuclear Information System (INIS)

Klein-Hessling, W.; Roewekamp, M.; Riese, O.

2006-11-01

Fire simulations as well as their analytical validation procedures have gained more and more significance, particularly in the context of the fire safety analysis for operating nuclear power plants. Meanwhile, fire simulation models have been adapted as analytical tools for a risk oriented fire safety assessment. Calculated predictions can be used, on the one hand, for the improvements and upgrades of fire protection in nuclear power plants by the licensees and, on the other hand, as a tool for reproducible and clearly understandable estimations in assessing the available and/or foreseen fire protection measures by the authorities and their experts. For consideration of such aspects in the context of implementing new nuclear fire protection standards or of updating existing ones, an 'International Collaborative Project to Evaluate Fire Models for Nuclear Power Plant Applications' also known as the 'International Collaborative Fire Model Project' (ICFMP) was started in 1999. It has made use of the experience and knowledge of a variety of worldwide expert institutions in this field to assess and improve, if necessary, the state-of-the-art with respect to modeling fires in nuclear power plants and other nuclear installations. This document contains the results of the ICFMP Benchmark Exercise No. 4, where two fuel pool fire experiments in an enclosure with two different natural vent sizes have been considered. Analyzing the results of different fire simulation codes and code types provides some indications with respect to the uncertainty of the results. This information is especially important in setting uncertainty parameters in probabilistic risk studies and to provide general insights concerning the applicability and limitations in the application of different types of fire simulation codes for this type of fire scenario and boundary conditions. During the benchmark procedure the participants performed different types of calculations. These included totally blind

Analysis of sodium pool fire in SFEF for assessing the limiting pool fire

International Nuclear Information System (INIS)

Mangarjuna Rao, P.; Ramesh, S.S.; Nashine, B.K.; Kasinathan, N.; Chellapandi, P.

2011-01-01

Accidental sodium leaks and resultant sodium fires in Liquid Metal Fast Breeder Reactor (LMFBR) systems can create a threat to the safe operation of the plant. To avoid this defence-in depth approach is implemented from the design stage of reactor itself. Rapid detection of sodium leak and fast dumping of the sodium into the storage tank of a defective circuit, leak collection trays, adequate lining of load bearing structural concrete and extinguishment of the sodium fire are the important defensive measures in the design, construction and operation of a LMFBR for protection against sodium leaks and their resultant fires. Evaluation of sodium leak events and their consequences by conducting large scale engineering experiments is very essential for effective implementation of the above protection measures for sodium fire safety. For this purpose a Sodium Fire Experimental Facility (SFEF) is constructed at SED, IGCAR. SFEF is having an experimental hall of size 9 m x 6 m x 10 m with 540 m 3 volume and its design pressure is 50 kPa. It is a concrete structure and provided with SS 304 liner, which is fixed to the inside surfaces of walls, ceiling and floor. A leak tight door of size (1.8 m x 2.0 m) is provided to the experimental hall and the facility is provided with a sodium equipment hall and a control room. Experimental evaluation of sodium pool fire consequences is an important activity in the LMFBR sodium fire safety related studies. An experimental program has been planned for different types of sodium fire studies in SFEF. A prior to that numerical analysis have been carried out for enclosed sodium pool fires using SOFIRE-II sodium pool fire code for SFEF experimental hall configuration to evaluate the limiting pool fire. This paper brings out results of the analysis carried out for this purpose. Limiting pool fire of SFEF depends on the exposed surface area of the pool, amount of sodium in the pool, oxygen concentration and initial sodium temperature. Limiting

How to reduce your fire insurance rates

Science.gov (United States)

Dubain, M.

1971-01-01

Construction procedures and utilization of materials to reduce the cost of insuring large buildings against losses from fire are discussed. Examples of good and bad techniques in building construction and fire safety management are provided. The inadequacies of building codes and the hazards resulting from improper construction are examined.

Experimental Benchmarking of Fire Modeling Simulations. Final Report

International Nuclear Information System (INIS)

Greiner, Miles; Lopez, Carlos

2003-01-01

A series of large-scale fire tests were performed at Sandia National Laboratories to simulate a nuclear waste transport package under severe accident conditions. The test data were used to benchmark and adjust the Container Analysis Fire Environment (CAFE) computer code. CAFE is a computational fluid dynamics fire model that accurately calculates the heat transfer from a large fire to a massive engulfed transport package. CAFE will be used in transport package design studies and risk analyses

Summary of HEDL sodium fire tests

International Nuclear Information System (INIS)

Hillard, R.K.

1978-10-01

The sodium fire test program and related studies at the Hanford Engineering Development Laboratory (HEDL) are described. The program is analytical and experimental in scope, with computer code development and experimental verification. Tests have ranged in size from gram quantity laboratory tests to 1600-kg sodium spills. The experimental work is performed in two facilities: the Large Sodium Fire Facility (LSFF) and the Containment Systems Test Facility (CSTF). Sodium fire extinguishment tests which verified the Fast Flux Test Facility (FFTF) secondary sodium fire protection system are described and related informaion on sodium burning rates and smoke release rates are correlated. The burning rates are compared to theoretical predictions based on heat and mass transfer analogy, with good agreement. Comparisons with the SOFIRE-II code are also made. Sodium combustion aerosol properties are defined as to chemical and physical nature, settling in closed vessels and effect of added water vapor. The HAA-3B aerosol behavior computer code is compared to tests in the 850-m 3 CSTF containment vessel. Sodium spray tests in the CSTF are compared with the SPRAY computer code. An air cleaning program is described, which has the objective of removing high mass concentration sodium combustion aerosols from vented cells and containment buildings. The aerosol mass holding capacity of commercial filters was measured and an aqueous scrubber system is described. The effects of sodium spills on cell structures were investigated, including water release from heated concrete, the reaction of sodium with concrete, the formation and spontaneous recombination of hydrogen, and the ability of steel cell liners to withstand large spills of high temperature sodium without leaking

CCDP evaluation of the fire areas of KSNP using CFAST

International Nuclear Information System (INIS)

Lee, Yoon Hwan; Yang, Joon Eon; Kim, Jong Hoon

2005-01-01

During the past decade, the nuclear power industry has been moving away from prescriptive rules and practices toward risk-informed and performance-based engineering analysis to support the decision making for plant fire protection programs. For example, the National Fire Protection Association (NFPA) prepared NFPA 805, Performance-Based Standard for Fire Protection for Light Water Reactor Electric Generating Plants 2001 Edition. One crucial element in supporting the risk-informed fire protection is availability of simple and reliable methods and tools for evaluating the likelihood and consequences of fire scenarios. These tools directly benefit risk-informed and performance-based fire protection and application of risk information to resolve fire protection issues. Now the deterministic analysis results for the cable integrity is not given in case of performing the fire PSA. So it is necessary to apply the results for the fire modeling to the fire PSA model to develop the more realistic model. This document is intended to analyze the peak temperature of the upper gas layer using the fire modeling code, CFAST , to evaluate the integrity of the cable located on the dominant pump rooms, and to assess the CCDP(Conditional Core Damage Probability) using the results of the cable integrity. Accordingly, the fire safety assessment for the dominant fire areas using the fire modeling code will be capable of evaluating the consequences of the fire scenario, of reducing the the uncertainty, and to develop a more realistic model

Model of fire spread around Krsko Power Plant

International Nuclear Information System (INIS)

Vidmar, P.; Petelin, S.

2001-01-01

The idea behind the article is how to define fire behaviour. The work is based on an analytical study of fire origin, its development and spread. The study is based on thermodynamics, heat transfer and the study of hydrodynamics and combustion, which represent the bases of fire dynamics. The article shows a practical example of a leak of hazardous chemicals from a tank. Because of the inflammability of the fluid, fire may start. We have tried to model fire propagation around the Krsko power plant, and show what extended surrounding area could be affected. The model also considers weather conditions, in particular wind speed and direction. For this purpose we have used the computer code Safer Trace, which is based on zone models. That means that phenomena are described by physical and empirical equations. An imperfection in this computer code is the inability to consider ground topology. However in the case of the Krsko power plant, topology is not so important, as the plan is located in a relatively flat region. Mathematical models are presented. They show the propagation of hazardous fluid in the environment considering meteorological data. The work also shows which data are essential to define fire spread and shows the main considerations of Probabilistic Safety Assessment for external fire event.(author)

Feedback from practical experience with large sodium fire accidents

International Nuclear Information System (INIS)

Luster, V.P.; Freudenstein, K.F.

1996-01-01

The paper reviews the important feedback from the practical experience from two large sodium fires; the first at ALMERIA in Spain and the second in the Na laboratories at Bensberg, Germany. One of the most important sodium fire accidents was the ALMERIA spray fire accident. The origin of this accident was the repair of a valve when about 14 t of sodium was spilled in the plant room over a period of 1/2 hour. The event has been reported (IAEA/IWGFR meeting in 1988) and this presentation gives a short review of important feedback. The Almeria accident was one of the reasons that from that time spray fires had to be taken into account in the safety analyses of nuclear power plants. Due to the fact that spray fire codes were not available in a sufficiently validated state, safety analyses were provisionally based on the feedback from sodium fire tests and also from the Almeria accident itself. The behaviour of spray fires showed that severe destruction, up to melting of metallic structures may occur, but even with a large spray fire is limited roughly within the spray fire zone itself. This could be subsequently be predicted by codes like NABRAND in Germany and FEUMIX in France. Almeria accident has accelerated R and D and code development with respect to spray fires. As example for a code validation some figures are given for the NABRAND code. Another large sodium fire accident happened in 1992 in the test facility at Bensberg in Germany (ILONA). This accident occurred during preheating of a sodium filled vessel which was provisionally installed in the basement of the ILONA test facility at Bensberg. Due to failure of a pressure relief valve the pressure in the vessel increased. As a consequence the plug in a dip tube for draining the vessel failed and about 4,5 t of sodium leaked slowly from the vessel. The plant room was not cladded with steel liners or collecting pans (it was not designed for permanent sodium plant operation). So leaking sodium came directly in

Large-scale pool fires

Directory of Open Access Journals (Sweden)

Steinhaus Thomas

2007-01-01

Full Text Available A review of research into the burning behavior of large pool fires and fuel spill fires is presented. The features which distinguish such fires from smaller pool fires are mainly associated with the fire dynamics at low source Froude numbers and the radiative interaction with the fire source. In hydrocarbon fires, higher soot levels at increased diameters result in radiation blockage effects around the perimeter of large fire plumes; this yields lower emissive powers and a drastic reduction in the radiative loss fraction; whilst there are simplifying factors with these phenomena, arising from the fact that soot yield can saturate, there are other complications deriving from the intermittency of the behavior, with luminous regions of efficient combustion appearing randomly in the outer surface of the fire according the turbulent fluctuations in the fire plume. Knowledge of the fluid flow instabilities, which lead to the formation of large eddies, is also key to understanding the behavior of large-scale fires. Here modeling tools can be effectively exploited in order to investigate the fluid flow phenomena, including RANS- and LES-based computational fluid dynamics codes. The latter are well-suited to representation of the turbulent motions, but a number of challenges remain with their practical application. Massively-parallel computational resources are likely to be necessary in order to be able to adequately address the complex coupled phenomena to the level of detail that is necessary.

Structural, Bioinformatic, and In Vivo Analyses of Two Treponema pallidum Lipoproteins Reveal a Unique TRAP Transporter

Energy Technology Data Exchange (ETDEWEB)

Deka, Ranjit K.; Brautigam, Chad A.; Goldberg, Martin; Schuck, Peter; Tomchick, Diana R.; Norgard, Michael V. (NIH); (UTSMC)

2012-05-25

Treponema pallidum, the bacterial agent of syphilis, is predicted to encode one tripartite ATP-independent periplasmic transporter (TRAP-T). TRAP-Ts typically employ a periplasmic substrate-binding protein (SBP) to deliver the cognate ligand to the transmembrane symporter. Herein, we demonstrate that the genes encoding the putative TRAP-T components from T. pallidum, tp0957 (the SBP), and tp0958 (the symporter), are in an operon with an uncharacterized third gene, tp0956. We determined the crystal structure of recombinant Tp0956; the protein is trimeric and perforated by a pore. Part of Tp0956 forms an assembly similar to those of 'tetratricopeptide repeat' (TPR) motifs. The crystal structure of recombinant Tp0957 was also determined; like the SBPs of other TRAP-Ts, there are two lobes separated by a cleft. In these other SBPs, the cleft binds a negatively charged ligand. However, the cleft of Tp0957 has a strikingly hydrophobic chemical composition, indicating that its ligand may be substantially different and likely hydrophobic. Analytical ultracentrifugation of the recombinant versions of Tp0956 and Tp0957 established that these proteins associate avidly. This unprecedented interaction was confirmed for the native molecules using in vivo cross-linking experiments. Finally, bioinformatic analyses suggested that this transporter exemplifies a new subfamily of TPATs (TPR-protein-associated TRAP-Ts) that require the action of a TPR-containing accessory protein for the periplasmic transport of a potentially hydrophobic ligand(s).

Fire protection in nuclear power plants

International Nuclear Information System (INIS)

1992-01-01

The Code on Design (Safety Series 50-C-D (Rev. 1)) within the NUSS (Nuclear Safety Standards) programme of the IAEA points out the necessity of measures for protecting plant items which are important to safety against fires of internal and external origin. Experience of the past two decades in the operation of nuclear power plants and modern analysis techniques confirm that fire may be a real threat to nuclear safety and should receive adequate attention from the beginning of the design process throughout the life of the plant. Within the framework of the NUSS programme, a Safety Guide on fire protection had therefore been developed to enlarge on the general requirements given in the Code. Since its first publication in 1979, there has been considerable development in protection technology and analysis methods and after the Chernobyl accident it was decided to revise the existing Guide. The present Safety Guide is intended to advise designers, safety assessors and regulators on the concept of fire protection in the design of nuclear power plants and on recommended ways of implementing the concept in some detail in practice. Figs, 1 tab

Theoretical modelling of the movement of sodium fire fumes in a building

International Nuclear Information System (INIS)

Vaughan, G.J.; Simpson, C.P.; Smith, A.G.

1989-01-01

The important effect that the thermal hydraulic behaviour in a containment can have on the burning rate of a sodium fire is discussed. To explore the nature of the convective motion induced y the fire and how these might be affected by the containment morphology, calculations with a thermal hydraulic code, PHOENICS, were carried out. This code has also been used to investigate the movement of the smoke cloud produced by a fire to support a study of the use of a venting system. Both studies are reported and some conclusions on the role of thermal hydraulic phenomena on sodium fire investigations are made. (author)

Summary of HEDL sodium fire tests

International Nuclear Information System (INIS)

Hilliard, R.K.

1979-01-01

The sodium fire test program and related studies at the Hanford Engineering Development Laboratory (HEDL), covering the period from 1972 to 1978, are described. The program is analytical and experimental in scope, with computer code development and experimental verification. Tests have ranged in size from gram quantity laboratory tests to 1600-kg sodium spills. The experimental work is performed in two facilities: the Large Sodium Fire Facility (LSFF) and the Containment Systems Test Facility (CSTF). The facilities are described and the experimental results summarized. Sodium fire extinguishment tests which verified the Fast Flux Test Facility (FFTF) secondary sodium fire protection system are described and related information on sodium burning rates and smoke release rates are correlated. The burning rates are compared to theoretical predictions based on heat and mass transfer analogy, with good agreement. Comparisons with the SOFIRE-II code are also made. Sodium combustion aerosol properties are defined as to chemical and physical nature, settling in closed vessels and effect of added water vapor. The HAA-38 aerosol behaviour computer code is compared to tests in the 850-m 3 CSTF containment vessel. Sodium spray tests in the CSTF are compared with the SPRAY computer code. An air cleaning program is described, which has the objective of removing high mass concentration sodium combustion aerosols from vented cells and containment buildings. The aerosol mass holding capacity of commercial filters was measured and an aqueous scrubber system is described. The effects of sodium spills on cell structures were investigated, including water release from heated concrete, the reaction of sodium with concrete, the formation and spontaneous recombination of hydrogen, and the ability of steel cell liners to withstand large spills of high temperature sodium without leaking. (author)

Summary of HEDL sodium fire tests

Energy Technology Data Exchange (ETDEWEB)

Hilliard, R K [Hanford Engineering Development Laboratory, Richland, WA (United States)

1979-03-01

The sodium fire test program and related studies at the Hanford Engineering Development Laboratory (HEDL), covering the period from 1972 to 1978, are described. The program is analytical and experimental in scope, with computer code development and experimental verification. Tests have ranged in size from gram quantity laboratory tests to 1600-kg sodium spills. The experimental work is performed in two facilities: the Large Sodium Fire Facility (LSFF) and the Containment Systems Test Facility (CSTF). The facilities are described and the experimental results summarized. Sodium fire extinguishment tests which verified the Fast Flux Test Facility (FFTF) secondary sodium fire protection system are described and related information on sodium burning rates and smoke release rates are correlated. The burning rates are compared to theoretical predictions based on heat and mass transfer analogy, with good agreement. Comparisons with the SOFIRE-II code are also made. Sodium combustion aerosol properties are defined as to chemical and physical nature, settling in closed vessels and effect of added water vapor. The HAA-38 aerosol behaviour computer code is compared to tests in the 850-m{sup 3} CSTF containment vessel. Sodium spray tests in the CSTF are compared with the SPRAY computer code. An air cleaning program is described, which has the objective of removing high mass concentration sodium combustion aerosols from vented cells and containment buildings. The aerosol mass holding capacity of commercial filters was measured and an aqueous scrubber system is described. The effects of sodium spills on cell structures were investigated, including water release from heated concrete, the reaction of sodium with concrete, the formation and spontaneous recombination of hydrogen, and the ability of steel cell liners to withstand large spills of high temperature sodium without leaking. (author)

Novel Treponema pallidum Recombinant Antigens for Syphilis Diagnostics: Current Status and Future Prospects

Directory of Open Access Journals (Sweden)

Aleksey Kubanov

2017-01-01

Full Text Available The recombinant protein technology considerably promoted the development of rapid and accurate treponema-specific laboratory diagnostics of syphilis infection. For the last ten years, the immunodominant recombinant inner membrane lipoproteins are proved to be sensitive and specific antigens for syphilis screening. However, the development of an enlarged T. pallidum antigen panel for diagnostics of early and late syphilis and differentiation of syphilis stages or cured syphilis remains as actual goal of multidisciplinary expertise. Current review revealed novel recombinant antigens: surface-exposed proteins, adhesins, and periplasmic and flagellar proteins, which are promising candidates for the improved syphilis serological diagnostics. The opportunities and limitations of diagnostic usage of these antigens are discussed and the criteria for selection of optimal antigens panel summarized.

Novel Treponema pallidum Recombinant Antigens for Syphilis Diagnostics: Current Status and Future Prospects.

Science.gov (United States)

Kubanov, Aleksey; Runina, Anastassia; Deryabin, Dmitry

2017-01-01

The recombinant protein technology considerably promoted the development of rapid and accurate treponema-specific laboratory diagnostics of syphilis infection. For the last ten years, the immunodominant recombinant inner membrane lipoproteins are proved to be sensitive and specific antigens for syphilis screening. However, the development of an enlarged T. pallidum antigen panel for diagnostics of early and late syphilis and differentiation of syphilis stages or cured syphilis remains as actual goal of multidisciplinary expertise. Current review revealed novel recombinant antigens: surface-exposed proteins, adhesins, and periplasmic and flagellar proteins, which are promising candidates for the improved syphilis serological diagnostics. The opportunities and limitations of diagnostic usage of these antigens are discussed and the criteria for selection of optimal antigens panel summarized.

Review of Differences of Steel related Properties between Proposals of European Structural Codes

DEFF Research Database (Denmark)

Hertz, Kristian Dahl

Differences of Steel related Properties between fire chapters of the Proposals of European Structural Codes are indicated for the same physical properties, the right properties are found and it is proposed to use these properties in all codes.......Differences of Steel related Properties between fire chapters of the Proposals of European Structural Codes are indicated for the same physical properties, the right properties are found and it is proposed to use these properties in all codes....

Parametric analysis of fire model CFAST

International Nuclear Information System (INIS)

Lee, Y. H.; Yang, J. Y.; Kim, J. H.

2004-01-01

This paper describes the pump room fire of the nuclear power plant using CFAST fire modeling code developed by NIST. It is determined by the constrained or unconstrained fire, Lower Oxygen Limit (LOL), Radiative Fraction (RF), and the times to open doors, which are the input parameters of CAFST. According to the results, pump room fire is ventilation-controlled fire, so it is adequate that the value of LOL is 10% which is also the default value. It is appeared that the RF does not change the temperature of the upper gas layer. But the level of opening of the penetrating area and the times to opening it have an effect on the temperature of the upper layer, so it is determined that the results of it should be carefully analyzed

An Assessment of the Fire Safety Hazard Associated with External Fire Spread in Tall Buildings with Combustible Façade Material

DEFF Research Database (Denmark)

Lavard Brogaard, Nicholas; Torero, Jose L.; Jomaas, Grunde

2014-01-01

in order to obtain a conclusive assessment of the fire safety hazards associated with combustible facades. Prescriptive fire safety codes are typically not allowing any type of combustible façade in buildings that are taller than 2-3 stories. However, a performance based approach does not contain height...

Oscillatory reactivity to effortful cognitive processing in the subthalamic nucleus and internal pallidum: a depth electrode EEG study

Czech Academy of Sciences Publication Activity Database

Bočková, M.; Chládek, Jan; Jurák, Pavel; Halámek, Josef; Rapcsak, S.Z.; Baláž, M.; Chrastina, J.; Rektor, I.

2017-01-01

Roč. 124, č. 7 (2017), s. 841-852 ISSN 0300-9564 R&D Projects: GA MZd(CZ) NV16-33798A; GA ČR GAP103/11/0933; GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : subthalamic nucleus * internal globus pallidum * complex cognitive functions * lateralization * deep brain stimulation * erd/s Subject RIV: FS - Medical Facilities ; Equipment OBOR OECD: Medical engineering Impact factor: 2.392, year: 2016

Exposure of a liquefied gas container to an external fire

International Nuclear Information System (INIS)

Raj, Phani K.

2005-01-01

In liquefied gas, bulk-storage facilities and plants, the separation distances between storage tanks and between a tank and a line of adjoining property that can be built are governed by local regulations and/or codes (e.g. National Fire Protection Association (NFPA) 58, 2004). Separation distance requirements have been in the NFPA 58 Code for over 60 years; however, no scientific foundations (either theoretical or experimental) are available for the specified distances. Even though the liquefied petroleum gas (LPG) industry has operated safely over the years, there is a question as to whether the code-specified distances provide sufficient safety to LPG-storage tanks, when they are exposed to large external fires. A radiation heat-transfer-based model is presented in this paper. The temporal variation of the vapor-wetted tank-wall temperature is calculated when exposed to thermal radiation from an external, non-impinging, large, 30.5 m (100 ft) diameter, highly radiative, hydrocarbon fuel (pool) fire located at a specified distance. Structural steel wall of a pressurized, liquefied gas container (such as the ASME LP-Gas tank) begins to lose its strength, when the wall temperature approaches a critical temperature, 810 K (1000 deg F). LP-Gas tank walls reaching close to this temperature will be a cause for major concern because of increased potential for tank failure, which could result in catastrophic consequences. Results from the model for exposure of different size ASME (LP-Gas) containers to a hydrocarbon pool fire of 30.5 m (100 ft) in diameter, located with its base edge at the separation distances specified by NFPA 58 [NFPA 58, Liquefied Petroleum Gas Code, Table 6.3.1, 2004 ed., National Fire Protection Association, Quincy, MA, 2004] indicate that the vapor-wetted wall temperature of the containers never reach the critical temperature under common wind conditions (0, 5 and 10 m/s), with the flame tilting towards the tank. This indicates that the separation

Safety design guides for fire protection for CANDU 9

International Nuclear Information System (INIS)

Lee, Duk Su; Chang, Woo Hyun; Lee, Nam Young; A. C. D. Wright

1996-03-01

This safety design guide establishes design requirements to ensure the radiological risk to the public due to fire is acceptable and operating personnel are adequately protected from the hazards of fires. This safety design guide also specifies the safety criteria for fire protection to be applied to mitigate fires and recommends the fire protection program to be established to initiate, coordinate and document the design activities associated with fire protection. The requirements for fire protection outlined in this safety design guide shall be satisfied in the design stage and the change status of the regulatory requirements, code and standards should be traced and incorporated into this safety design guide accordingly. 1 fig., (Author) .new

Numerical prediction of heat-flux to massive calorimeters engulfed in regulatory fires with the cask analysis fire environment (CAFE) model

International Nuclear Information System (INIS)

Koski, Jorman A.; Suo-Antitla, Ahti; Kramer M, Alex; Greiner, Miles

2000-01-01

Recent observations show that the thermal boundary conditions within large-scale fires are significantly affected by the presence of thermally massive objects. These objects cool the soot and gas near their surfaces, and these effects reduce the incoming radiant heat-flux to values lower than the levels expected from simple σT fire 4 models. They also affect the flow and temperature fields in the fire far from their surfaces. The Cask Analysis Fire Environment (CAFE) code has been developed at Sandia National Laboratories to provide an enhanced fire boundary condition for the design of radioactive material packages. CAFE is a set of computer subroutines that use computational fluid mechanics methods to predict convective heat transfer and mixing. It also includes models for fuel and oxygen transport, chemical reaction, and participating-media radiation heat transfer. This code uses two-dimensional computational models so that it has reasonably short turnaround times on standard workstations and is well suited for design and risk studies. In this paper, CAFE is coupled with a commercial finite-element program to model a large cylindrical calorimeter fully engulfed in a pool fire. The time-dependent heat-flux to the calorimeter and the calorimeter surface temperature are determined for several locations around the calorimeter circumference. The variation of heat-flux with location is determined for calorimeters with different diameters and wall thickness, and the observed effects discussed

FDS5 Simulation for OECD PRISME Fire Test of DOOR PRSD5

International Nuclear Information System (INIS)

Lee, Kyu Bok; Park, Jong Seuk

2009-01-01

OECD/NEA PRISME Fire Project is an international co-operation project to investigate fire propagation by means of experiments and analyses for nuclear power plant applications. This project focuses on the generation of experimental data for fire and smoke propagation from the fire room to adjacent rooms under various conditions and room configurations. In addition, analyses using computer codes are performed to understand the phenomena of interest and to produce a consistent interpretation of the experimental results. The PRISME Project is composed of series of tests named as SOURCE, DOOR, LEAK and Global Tests. The SOURCE is composed of tests to characterize the fire source, and the DOOR is to study fire and smoke propagation through an open door, while the LEAK is to investigate hot gas leakages through other modes of openings such as holes, a slot, a duct, and a partially opened door. The Global test will be conducted as integral tests on the basis of the results of the previous separate effects tests. In this paper, simulations are performed with FDS5 computer code for the DOOR Test No.5 (PRS D 5) and the calculation results are compared with the corresponding experimental data to study the code capability to predict the phenomena of the hot gas propagation between two rooms

Seroprevalence of the Hepatitis B, Hepatitis C, and Human Immunodeficiency Viruses and Treponema pallidum at the Beijing General Hospital from 2010 to 2014: A Cross-Sectional Study.

Directory of Open Access Journals (Sweden)

Shaoxia Xu

Full Text Available The hepatitis B, hepatitis C, human immunodeficiency viruses and Treponema pallidum are important causes of infectious diseases concern to public health.Between 2010 and 2014, we used an automated chemiluminescence microparticle immunoassay to detect the hepatitis B, hepatitis C, and human immunodeficiency viruses as well as Treponema pallidum (the rapid plasma regain test was used in 2010-2011. Positive human immunodeficiency virus tests were confirmed via western blotting.Among 416,130 subjects, the seroprevalences for hepatitis B virus, hepatitis C virus, human immunodeficiency virus, and Treponema pallidum were 5.72%, 1.23%, 0.196%, and 0.76%, respectively. Among 671 patients with positive human immunodeficiency virus results, 392 cases were confirmed via western blotting. Hepatitis B and human immunodeficiency virus infections were more frequent in men (7.78% and 0.26%, respectively than in women (4.45% and 0.021%, respectively. The hepatitis B and C virus seroprevalences decreased from 6.21% and 1.58%, respectively, in 2010, to 5.37% and 0.988%, respectively, in 2014. The human immunodeficiency virus seroprevalence increased from 0.04% in 2010 to 0.17% in 2014, and was elevated in the Infectious Disease (2.65%, Emergency (1.71%, and Dermatology and Sexually Transmitted Diseases (1.12% departments. The specificity of the human immunodeficiency virus screening was 71.4%. The false positive rates for the Treponema pallidum screening tests increased in patients who were 60-70 years old. The co-infection rates for the hepatitis C and human immunodeficiency viruses were 0.47% in hepatitis C virus-positive patients and 7.33% in human immunodeficiency virus-positive patients.During 2010-2014, hepatitis B virus and human immunodeficiency virus infections were more frequent among men at our institution. Although the seroprevalences of hepatitis B and C viruses decreased, the seroprevalence of human immunodeficiency virus infection increased (with

Protection against Syphilis Correlates with Specificity of Antibodies to the Variable Regions of Treponema pallidum Repeat Protein K

OpenAIRE

Morgan, Cecilia A.; Lukehart, Sheila A.; Van Voorhis, Wesley C.

2003-01-01

Syphilis has been recognized as a disease since the late 1400s, yet there is no practical vaccine available. One impediment to the development of a vaccine is the lack of understanding of multiple reinfections in humans despite the development of robust immune responses during the first episode. It has been shown that the Treponema pallidum repeat protein K (TprK) differs in seven discrete variable (V) regions in isolates and that the antibody response during infection is directed to these V ...

Fire resistance of extruded hollow-core slabs

DEFF Research Database (Denmark)

Hertz, Kristian Dahl; Sørensen, Lars Schiøtt; Giuliani, Luisa

2017-01-01

to the structural codes with data derived from a standard fire test and from a thorough examination of the comprehensive test documentation available on fire exposed hollow-core slabs. Findings – Mechanisms for loss of load-bearing capacity are clarified, and evidence of the fire resistance is found. Originality......Purpose – Prefabricated extruded hollow-core slabs are preferred building components for floor structures in several countries. It is therefore important to be able to document the fire resistance of these slabs proving fulfilment of standard fire resistance requirements of 60 and 120 min found...... in most national building regulations. The paper aims to present a detailed analysis of the mechanisms responsible for the loss of loadbearing capacity of hollow-core slabs when exposed to fire. Design/methodology/approach – Furthermore, it compares theoretica calculation and assessment according...

Fire protection for telecommunications central offices

International Nuclear Information System (INIS)

McKenna, L.A. Jr.

1990-01-01

The provision of continuous, uninterrupted telecommunications service is vital to modern life. In order to provide uninterrupted service to customers, a service continuity program has been in place with AT and T for many years. This program integrates many different protection strategies and plans, each designed to mitigate one of the many threats to service continuity. The fire protection program implemented within AT and T is a part of this service continuity program. In the design of this program, a number of unusual problems had to be addressed due to the service continuity requirements. Typical solutions to fire protection problems (ignition prevention, detection, and suppression) which are embodied in building and fire prevention codes are inadequate to provide service continuity. This presentation outlines the basic arrangement of a telecommunications central office, the specific fire protection problems encountered, the fire protection philosophy developed through the use of a systems approach, and the implementation of the fire protection program. Special emphasis is placed on the strategies employed in lieu of more traditional fire protection schemes and the stimuli for selecting them

Optogenetic Inhibition of Ventral Pallidum Neurons Impairs Context-Driven Salt Seeking.

Science.gov (United States)

Chang, Stephen E; Smedley, Elizabeth B; Stansfield, Katherine J; Stott, Jeffrey J; Smith, Kyle S

2017-06-07

Salt appetite, in which animals can immediately seek out salt when under a novel state of sodium deprivation, is a classic example of how homeostatic systems interface with learned associations to produce an on-the-fly updating of motivated behavior. Neural activity in the ventral pallidum (VP) has been shown to encode changes in the value of salt under such conditions, both the value of salt itself (Tindell et al., 2006) and the motivational value of its predictive cues (Tindell et al., 2009; Robinson and Berridge, 2013). However, it is not known whether the VP is necessary for salt appetite in terms of seeking out salt or consuming salt following sodium depletion. Here, we used a conditioned place-preference procedure to investigate the effects of optogenetically inhibiting the VP on context-driven salt seeking and the consumption of salt following deprivation. Male rats learned to associate one context with sucrose and another context with less-desirable salt. Following sodium depletion, and in the absence of either sucrose or salt, we found that inhibiting the VP selectively reduced the elevation in time spent in the salt-paired context. VP inhibition had minimal effects on the consumption of salt once it was made available. To our knowledge, this is the first evidence that the VP or any brain region is necessary for the ability to use contextual cues to guide salt seeking. These results highlight a dissociation between deficit-driven reward seeking and reward consumption to replenish those deficits, with the former process being particularly sensitive to on-line VP activity. SIGNIFICANCE STATEMENT Salt appetite, in which rats will immediately seek out a once-undesirable concentrated salt solution after being depleted of bodily sodium despite never having tasted salt as a positive reward, is a phenomenon showing how animals can update their motivational goals without any new learning or conditioning. This salt-seeking behavior is also observed when the animal

French research on a general approach to sodium fires

International Nuclear Information System (INIS)

Malet, JC.

1989-01-01

This document gives a general idea of how one may deal with the safety of an installation in case of a sodium leak generating either a sodium pool fire, or a sodium spray fire, or a combined sodium fire, and in case of a sodium leak either with or without fire and/or any aggravating phenomenon such as aerosols or sodium-concrete reactions, for example. This paper describes the means used to reduce fire consequences. These means are either design codes used for dimensioning premises with their ventilation system or for defining a course of action to be taken in case of fire, or equipment and components (fire fighting equipment, detection devices, etc.) used to prevent or to fight fires, or finally, to repair the installation after a fire, the latter operation including the processing of the residues. (author)

77 FR 58081 - Protection of Stratospheric Ozone: Listing of Substitutes for Ozone-Depleting Substances-Fire...

Science.gov (United States)

2012-09-19

... 332919 Nozzles, fire fighting, manufacturing. Manufacturing 334290 Fire detection and alarm systems... substitutes for halon 1301 for use in total flooding fire suppression systems in normally unoccupied spaces... regulated Category NAICS Code entities Construction 238210 Alarm system (e.g., fire, burglar), electric...

CAFE: A Computer Tool for Accurate Simulation of the Regulatory Pool Fire Environment for Type B Packages

International Nuclear Information System (INIS)

Gritzo, L.A.; Koski, J.A.; Suo-Anttila, A.J.

1999-01-01

The Container Analysis Fire Environment computer code (CAFE) is intended to provide Type B package designers with an enhanced engulfing fire boundary condition when combined with the PATRAN/P-Thermal commercial code. Historically an engulfing fire boundary condition has been modeled as σT 4 where σ is the Stefan-Boltzman constant, and T is the fire temperature. The CAFE code includes the necessary chemistry, thermal radiation, and fluid mechanics to model an engulfing fire. Effects included are the local cooling of gases that form a protective boundary layer that reduces the incoming radiant heat flux to values lower than expected from a simple σT 4 model. In addition, the effect of object shape on mixing that may increase the local fire temperature is included. Both high and low temperature regions that depend upon the local availability of oxygen are also calculated. Thus the competing effects that can both increase and decrease the local values of radiant heat flux are included in a reamer that is not predictable a-priori. The CAFE package consists of a group of computer subroutines that can be linked to workstation-based thermal analysis codes in order to predict package performance during regulatory and other accident fire scenarios

Application Study of Fire Severity Classification

International Nuclear Information System (INIS)

Kim, In Hwan; Kim, Hyeong Taek; Jee, Moon Hak; Kim, Yun Jung

2013-01-01

This paper introduces the Fire Incidents Severity Classification Method for Korean NPPs that may be derived directly from the data fields and feasibility study for domestic uses. FEDB was characterized in more detail and assessed based on the significance of fire incidents in the updated database and five fire severity categories were defined. The logical approach to determine the fire severity starts from the most severe characteristics, namely challenging fires, and continues to define the less challenging and undetermined categories in progress. If the FEDB is utilized for Korean NPPs, the ways of Fire Severity Classification suggested in 2.4 above can be utilized for the quantitative fire risk analysis in future. The Fire Events Database (FEDB) is the primary source of fire data which are used for fire frequency in Fire PSA (Probabilistic Safety Assessment). The purpose of its development is to calculate the quantitative fire frequency at the comprehensive and consolidated source derived from the fire incident information available for Nuclear Power Plants (NPPs). Recently, the Fire Events Database (FEDB) was updated by Electric Power Research Institute (EPRI) and Nuclear Regulatory Commission (NRC) in U. S. The FEDB is intended to update the fire event history up to 2009. A significant enhancement to it is the reorganization and refinement of the database structure and data fields. It has been expanded and improved data fields, coding consistency, incident detail, data review fields, and reference data source traceability. It has been designed to better support several Fire PRA uses as well

The Calculation and Design of Fire suppression system in the proton accelerator research center

International Nuclear Information System (INIS)

Jeon, G. P.; Kim, J. Y.; Cho, J. H.; Min, Y. S.; Mun, K. J.; Cho, J. S.; Nam, J. M.; Park, S. S.; Joo, H. G.

2010-01-01

The fire protection system is composed of various fire suppression systems and fire detection and alarm systems. The primary function of the fire protection system is to protect life and property from a fire through detecting fires quickly and suppressing those fires that occur. In this paper, we described the fire suppression system only. The fire suppression system capacity for fire hydrant, the water mist system, sprinkler system and clean agent system is calculated and designed in compliance with the applicable Korean Acts that are applicable to fire protection and the NFSC code

One Approach to the Fire PSA Uncertainty Analysis

International Nuclear Information System (INIS)

Simic, Z.; Mikulicic, V.; Vukovic, I.

2002-01-01

Experienced practical events and findings from the number of fire probabilistic safety assessment (PSA) studies show that fire has high relative importance for nuclear power plant safety. Fire PSA is a very challenging phenomenon and a number of issues are still in the area of research and development. This has a major impact on the conservatism of fire PSA findings. One way to reduce the level of conservatism is to conduct uncertainty analysis. At the top-level, uncertainty of the fire PSA can be separated in to three segments. The first segment is related to fire initiating events frequencies. The second uncertainty segment is connected to the uncertainty of fire damage. Finally, there is uncertainty related to the PSA model, which propagates this fire-initiated damage to the core damage or other analyzed risk. This paper discusses all three segments of uncertainty. Some recent experience with fire PSA study uncertainty analysis, usage of fire analysis code COMPBRN IIIe, and uncertainty evaluation importance to the final result is presented.(author)

Enclosure environment characterization testing for the base line validation of computer fire simulation codes

International Nuclear Information System (INIS)

Nowlen, S.P.

1987-03-01

This report describes a series of fire tests conducted under the direction of Sandia National Laboratories for the US Nuclear Regulatory Commission. The primary purpose of these tests was to provide data against which to validate computer fire environment simulation models to be used in the analysis of nuclear power plant enclosure fire situations. Examples of the data gathered during three of the tests are presented, though the primary objective of this report is to provide a timely description of the test effort itself. These tests were conducted in an enclosure measuring 60x40x20 feet constructed at the Factory Mutual Research Corporation fires test facility in Rhode Island. All of the tests utilized forced ventilation conditions. The ventilation system was designed to simulate typical nuclear power plant installation practices and ventilation rates. A total of 22 tests using simple gas burner, heptane pool, methanol pool, and PMMA solid fires was conducted. Four of these tests were conducted with a full-scale control room mockup in place. Parameters varied during testing were fire intensity, enclosure ventilation rate, and fire location. Data gathered include air temperatures, air velocities, radiative and convective heat flux levels, optical smoke densities, inner and outer enclosure surface temperatures, enclosure surface heat flux levels, and gas concentrations within the enclosure in the exhaust stream

Sodium pool fire analysis of sodium-cooled fast reactor by calculation

International Nuclear Information System (INIS)

Yu Hong; Xu Mi; Jin Degui

2002-01-01

Theoretical models were established according to the characteristic of sodium pool fire, and the SPOOL code was created independently. Some transient processes in sodium pool fire were modeled, including chemical reaction of sodium and oxygen; sodium combustion heat transfer modes in several kids of media; production, deposition and discharge of sodium aerosol; mass and energy exchange between different media in different ventilating conditions. The important characteristic parameters were calculated, such as pressure and temperature of gas, temperature of building materials, mass concentration of sodium aerosol, and so on. The SPOOL code, which provided available safety analysis tool for sodium pool fire accidents in sodium-cooled fast reactor, was well demonstrated with experimental data

77 FR 34020 - National Fire Codes: Request for Public Input for Revision of Codes and Standards

Science.gov (United States)

2012-06-08

.... (CO) Detection and Warning Equipment. NFPA 790--2012 Standard for Competency of Third-Party Field 6/22... Health-Related Fitness Programs for 1/4/2013. Fire Department Members. NFPA 1584--2008 Standard on the...

Study on eliminating fire dampers to maintain process confinement

International Nuclear Information System (INIS)

Walling, R.C.; Patel, J.B.; Strunk, A.J.

1991-01-01

The DOE General Design Criteria for the Defense Waste Processing Facility (DWPF) at the Westinghouse Savannah River Site (WSRS) requires the NFPA National Fire Codes to be incorporated into the design and simultaneously maintain process confinement integrity to prevent the release of radioactivity. Although the NFPA Standard for the Installation of Air Conditioning and Ventilation Systems, NFPA 90, requires fire dampers (FD) in HVAC duct penetrations of two hour rated fire barriers, closure of fire dampers at DWPF may compromise the integrity of the process confinement system. This leads to the need for an overall risk assessment to determine the value of 39 fire dampers that are identified later in the study as capable of a confinement system upset

The Coding Question.

Science.gov (United States)

Gallistel, C R

2017-07-01

Recent electrophysiological results imply that the duration of the stimulus onset asynchrony in eyeblink conditioning is encoded by a mechanism intrinsic to the cerebellar Purkinje cell. This raises the general question - how is quantitative information (durations, distances, rates, probabilities, amounts, etc.) transmitted by spike trains and encoded into engrams? The usual assumption is that information is transmitted by firing rates. However, rate codes are energetically inefficient and computationally awkward. A combinatorial code is more plausible. If the engram consists of altered synaptic conductances (the usual assumption), then we must ask how numbers may be written to synapses. It is much easier to formulate a coding hypothesis if the engram is realized by a cell-intrinsic molecular mechanism. Copyright © 2017 Elsevier Ltd. All rights reserved.

Literature study regarding fire protection in nuclear power plants. Part I: Fire rated separations; Litteraturstudie angaaende brandskydd i kaernkraftverk. Del I: Brandteknisk separation

Energy Technology Data Exchange (ETDEWEB)

Isaksson, S [Swedish Testing and Research Inst., Boraas (Sweden)

1995-06-01

This literature study has been made on behalf of the Swedish Nuclear Power Inspectorate. The aim is to describe different aspects of fire protection in nuclear power plants. Conventional building codes can not give guidance on where to make fire rated separations in order to separate redundant trains of safety systems. The separation must originate in functional demands from the authorities on what functions are essential during and after a fire, and under what circumstances these functions shall be retained, i.e. the number of independent faults and initiating events. As a basic demand it is suggested to rate the strength of separations according to conventional building code, based on fire load. The whole separating construction shall have the same fire rating, including the ventilation system. Deviations from the basic demand can de done in case it can be proven that it is possible to compensate some or all of the fire rating with other measures. There is a general lack of statistical information regarding the reliability of fire separating constructions such as walls, fire doors, penetration seals and fire dampers. The amount of cables penetrating a seal is in many cases much higher in real installations than what has been tested for type approval. It would therefore be valuable to perform a furnace test with a more representative amount of cables passing through a penetration seal. Tests have shown that the 20 foot horizontal separation distance stipulated by NRC is not a guarantee against fire damage. Spatial separations based on general requirements shall not be allowed, but considered from case to case based on actual circumstances. For fire protection by isolation or coatings, it is of great importance to choose the method of protection carefully, to be compatible with the material it shall be applied on, and the environment and types of fire that may occur. 48 refs, 2 figs, 5 tabs.

Possibility of Fire Accident Analysis in Road Tunnel

Directory of Open Access Journals (Sweden)

Peter Vidmar

2004-09-01

Full Text Available The basic aim of this treatise is to research the relevant featuresof the control and management of fire event in road tunnels.The simulation of 200 meters long cut out of the road tunnelis performed with the computer code FDS (Fire DynamicsSimulator which is based on the computational fluid dynamics.FDS is used to simulate fire dynamics behavior in three differentscenarios: natural ventilation, forced ventilation with axialventilators and vertical smoke extraction.It is believed that the present research, the methodology appliedand its findings should promote and improve safety andreliability of fire safety in road tunnels and to cope with thecomplex contemporary logistic demands of safety and reliabilityin the transportation of passengers and goods.

Fire protection for nuclear power plants. Part 1. Fundamental approaches. Version 6/99

International Nuclear Information System (INIS)

1999-06-01

The KTA nuclear safety code sets out the fundamental approaches and principles for the prevention of fires in nuclear power plants, addressing aspects such as initiation, spreading, and effects of a fire: (a) Fire load and ignition sources, (b) structural and plant engineering conditions, (c) ways and means relating to fire call and fire fighting. Relevant technical and organisational measures are defined. Scope and quality of fire prevention measures to be taken, as well the relevant in-service inspection activities are determined according to the protective goals pursued in each case. (orig./CB) [de

Fire safety

International Nuclear Information System (INIS)

Keski-Rahkonen, O.; Bjoerkman, J.; Hostikka, S.; Mangs, J.; Huhtanen, R.; Palmen, H.; Salminen, A.; Turtola, A.

1998-01-01

According to experience and probabilistic risk assessments, fires present a significant hazard in a nuclear power plant. Fires may be initial events for accidents or affect safety systems planned to prevent accidents and to mitigate their consequences. The project consists of theoretical work, experiments and simulations aiming to increase the fire safety at nuclear power plants. The project has four target areas: (1) to produce validated models for numerical simulation programmes, (2) to produce new information on the behavior of equipment in case of fire, (3) to study applicability of new active fire protecting systems in nuclear power plants, and (4) to obtain quantitative knowledge of ignitions induced by important electric devices in nuclear power plants. These topics have been solved mainly experimentally, but modelling at different level is used to interpret experimental data, and to allow easy generalisation and engineering use of the obtained data. Numerical fire simulation has concentrated in comparison of CFD modelling of room fires, and fire spreading on cables on experimental data. So far the success has been good to fair. A simple analytical and numerical model has been developed for fire effluents spreading beyond the room of origin in mechanically strongly ventilated compartments. For behaviour of equipment in fire several full scale and scaled down calorimetric experiments were carried out on electronic cabinets, as well as on horizontal and vertical cable trays. These were carried out to supply material for CFD numerical simulation code validation. Several analytical models were developed and validated against obtained experimental results to allow quick calculations for PSA estimates as well as inter- and extrapolations to slightly different objects. Response times of different commercial fire detectors were determined for different types of smoke, especially emanating from smoldering and flaming cables to facilitate selection of proper detector

TEMPERATURE HETEROGENEITY OF TRAVELLING FIRE AND ITS INFLUENCE ON COMPOSITE STEEL-CONCRETE FLOOR

Directory of Open Access Journals (Sweden)

Kamila Horová

2016-04-01

Full Text Available In order to follow modern trends in contemporary building architecture, which is moving off the limits of current fire design models, assumption of homogeneous temperature conditions used for structural fire analysis needs to be revised. In this paper fire dynamics of travelling fire is investigated experimentally by conducting fire test in two-storey experimental building. To evaluate the impact of travelling fire on the mechanical behaviour of a structure, the spatial and temporal evolution of the gas temperature calculated in NIST code FDS, which was validated to experimental measurements, is applied to the composite floor of dimensions 9.0 m by 9.0 m. Mechanical behaviour of the composite slab highly affected by regions of high temperatures and areas with only elevated temperatures is solved in code Vulcan. To highlight the severity of spreading fire causing non-uniform temperature conditions, which after-effects differ from traditional methods, a comparison of both methods is introduced. The calculation of mechanical behaviour of the composite floor is repeated in a series of three different thermal loading cases. Results of all cases are then compared in terms of vertical displacement and axial force in several positions of the composite floor.

Passive fire protection role and evolutions

Energy Technology Data Exchange (ETDEWEB)

Cerosky, Tristan [NUVIA (France); Perdrix, Johan [NUVIA Protection (France)

2015-12-15

Major incidents associated with nuclear power plants often invoke a re-examination of key safety barriers. Fire hazard, in particular, is a key concern for safe operation of nuclear power plants given its propensity to damage safety systems which could ultimately lead to radioactive release into the atmosphere. In the recent past, events such as the Fukushima disaster have led to an industry-wide push to improve nuclear safety arrangements. As part of these measures, upgrading of fire safety systems has received significant attention. In addition to the inherent intricacies associated with such a complex undertaking, factors such as frequent changes in the national and European fire regulations also require due attention while formulating a fire protection strategy. This paper will highlight some salient aspects underpinning an effective fire protection strategy. This will involve: A) A comprehensive introduction to the different aspects of fire safety (namely prevention, containment and mitigation) supported by a review of the development of the RCC-I from 1993 to 1997 editions and the ETC-F (AFCEN codes used by EDF in France). B) Development of the fire risk analysis methodology and the different functions of passive fire protection within this method involving confinement and protection of safety-related equipment. C) A review of the benefits of an effective passive fire protection strategy, alongside other arrangements (such as active fire protection) to a nuclear operator in term of safety and cost savings. It is expected that the paper will provide nuclear operators useful guidelines for strengthening existing fire protection systems.

Complete genome sequences of two strains of Treponema pallidum subsp. pertenue from Ghana, Africa: Identical genome sequences in samples isolated more than 7 years apart.

Directory of Open Access Journals (Sweden)

Michal Strouhal

2017-09-01

Full Text Available Treponema pallidum subsp. pertenue (TPE is the causative agent of yaws, a multi-stage disease, endemic in tropical regions of Africa, Asia, Oceania, and South America. To date, four TPE strains have been completely sequenced including three TPE strains of human origin (Samoa D, CDC-2, and Gauthier and one TPE strain (Fribourg-Blanc isolated from a baboon. All TPE strains are highly similar to T. pallidum subsp. pallidum (TPA strains. The mutation rate in syphilis and related treponemes has not been experimentally determined yet.Complete genomes of two TPE strains, CDC 2575 and Ghana-051, that infected patients in Ghana and were isolated in 1980 and 1988, respectively, were sequenced and analyzed. Both strains had identical consensus genome nucleotide sequences raising the question whether TPE CDC 2575 and Ghana-051 represent two different strains. Several lines of evidence support the fact that both strains represent independent samples including regions showing intrastrain heterogeneity (13 and 5 intrastrain heterogeneous sites in TPE Ghana-051 and TPE CDC 2575, respectively. Four of these heterogeneous sites were found in both genomes but the frequency of alternative alleles differed. The identical consensus genome sequences were used to estimate the upper limit of the yaws treponeme evolution rate, which was 4.1 x 10-10 nucleotide changes per site per generation.The estimated upper limit for the mutation rate of TPE was slightly lower than the mutation rate of E. coli, which was determined during a long-term experiment. Given the known diversity between TPA and TPE genomes and the assumption that both TPA and TPE have a similar mutation rate, the most recent common ancestor of syphilis and yaws treponemes appears to be more than ten thousand years old and likely even older.

Fire protection of safe shutdown capability at commercial nuclear power plants

International Nuclear Information System (INIS)

Sullivan, K.

1993-01-01

The comprehensive industrial safety standards and codes that exist today have evolved from lessons learned through past experience, research results, and improvements in technological capabilities. The current requirements for fire safety features of commercial nuclear power stations operated in the U.S. are a notable example of this practice. Although fire protection has always been an important design requirement, from the aftermath of a serious fire that occurred in 1975 at the Browns Ferry plant, it was learned that the life safety and property protection concerns of the major fire insurance underwriters may not sufficiently encompass nuclear safety issues, particularly with regard to the potential for fire damage to result in the common mode failure of redundant trains of systems, and composites important to the safe shutdown of the reactor. Following its investigations into the Browns Ferry fire, the Nuclear Regulatory Commission (NRC) promulgated guidance documents, which ultimately developed into mandatory regulations, necessary to assure the implementation of a fire protection program that would address nuclear safety concerns. The new criteria that evolved, contain prescriptive design features, as well as personnel and administrative requirements the Commission determined to be necessary to provide a defense-in-depth level of protection against the hazards of fire and its associated effects on safety related equipment. These criteria are primarily contained in Appendix R of Title 10 to the Code of Federal Regulations (10 CFR 50)

Variable synaptic strengths controls the firing rate distribution in feedforward neural networks.

Science.gov (United States)

Ly, Cheng; Marsat, Gary

2018-02-01

Heterogeneity of firing rate statistics is known to have severe consequences on neural coding. Recent experimental recordings in weakly electric fish indicate that the distribution-width of superficial pyramidal cell firing rates (trial- and time-averaged) in the electrosensory lateral line lobe (ELL) depends on the stimulus, and also that network inputs can mediate changes in the firing rate distribution across the population. We previously developed theoretical methods to understand how two attributes (synaptic and intrinsic heterogeneity) interact and alter the firing rate distribution in a population of integrate-and-fire neurons with random recurrent coupling. Inspired by our experimental data, we extend these theoretical results to a delayed feedforward spiking network that qualitatively capture the changes of firing rate heterogeneity observed in in-vivo recordings. We demonstrate how heterogeneous neural attributes alter firing rate heterogeneity, accounting for the effect with various sensory stimuli. The model predicts how the strength of the effective network connectivity is related to intrinsic heterogeneity in such delayed feedforward networks: the strength of the feedforward input is positively correlated with excitability (threshold value for spiking) when firing rate heterogeneity is low and is negatively correlated with excitability with high firing rate heterogeneity. We also show how our theory can be used to predict effective neural architecture. We demonstrate that neural attributes do not interact in a simple manner but rather in a complex stimulus-dependent fashion to control neural heterogeneity and discuss how it can ultimately shape population codes.

Fire Risk Analysis and Optimization of Fire Prevention Management for Green Building Design and High Rise Buildings: Hong Kong Experience

Directory of Open Access Journals (Sweden)

Yau Albert

2014-12-01

Full Text Available There are many iconic high rise buildings in Hong Kong, for example, International Commercial Centre, International Financial Centre, etc. Fire safety issue in high rise buildings has been raised by local fire professionals in terms of occupant evacuation, means of fire-fighting by fire fighters, sprinkler systems to automatically put off fires in buildings, etc. Fire risk becomes an important issue in building fire safety because it relates to life safety of building occupants where they live and work in high rise buildings in Hong Kong. The aim of this research is to identify the fire risk for different types of high rise buildings in Hong Kong and to optimise the fire prevention management for those high rise buildings with higher level of fire risk and to validate the model and also to carry out the study of the conflict between the current fire safety building code and the current trend of green building design. Survey via the 7-point scale questionnaire was conducted through 50 participants and their responses were received and analysed via the statistical tool SPSS software computer program. A number of statistical methods of testing for significantly difference in samples were adopted to carry out the analysis of the data received. When the statistical analysis was completed, the results of the data analysis were validated by two Fire Safety Experts in this area of specialisation and also by quantitative fire risk analysis.

A safety evaluation of fire and explosion in nuclear fuel reprocessing plants

International Nuclear Information System (INIS)

Nishio, Gunji; Takada, Junichi; Tukamoto, Michio; Watanabe, Kouji; Miyata, Teijirou

1996-01-01

The demonstration test was performed in JAERI to prove the adequacy of a safety evaluation for an air-ventilation system in the case of solvent fire and red-oil explosion in a nuclear fuel reprocessing plant. The test objectives were to obtain data of the safety evaluation on a thermofluid behavior and a confinement effect of radioactive materials during fire and explosion while the system is operating in a cell. The computer code was developed to evaluate the safety of associated network in the ventilation system and to estimate the confinement of radioactive materials in the system. The code was verified by comparison of code calculations with results of the demonstration test. (author)

77 FR 31325 - National Fire Codes: Request for Comments on NFPA Technical Committee Reports

Science.gov (United States)

2012-05-25

... Fire Protection of Commercial Cooking Operations. NFPA 130 Standard for Fixed Guideway P Transit and... Apparatus P Driver/Operator Professional Qualifications. NFPA 1021 Standard for Fire Officer P Professional Qualifications. NFPA 1026 Standard for Incident P Management Personnel Professional Qualifications. NFPA 1031...

Modeling and Analysis of Realistic Fire Scenarios in Spacecraft

Science.gov (United States)

Brooker, J. E.; Dietrich, D. L.; Gokoglu, S. A.; Urban, D. L.; Ruff, G. A.

2015-01-01

An accidental fire inside a spacecraft is an unlikely, but very real emergency situation that can easily have dire consequences. While much has been learned over the past 25+ years of dedicated research on flame behavior in microgravity, a quantitative understanding of the initiation, spread, detection and extinguishment of a realistic fire aboard a spacecraft is lacking. Virtually all combustion experiments in microgravity have been small-scale, by necessity (hardware limitations in ground-based facilities and safety concerns in space-based facilities). Large-scale, realistic fire experiments are unlikely for the foreseeable future (unlike in terrestrial situations). Therefore, NASA will have to rely on scale modeling, extrapolation of small-scale experiments and detailed numerical modeling to provide the data necessary for vehicle and safety system design. This paper presents the results of parallel efforts to better model the initiation, spread, detection and extinguishment of fires aboard spacecraft. The first is a detailed numerical model using the freely available Fire Dynamics Simulator (FDS). FDS is a CFD code that numerically solves a large eddy simulation form of the Navier-Stokes equations. FDS provides a detailed treatment of the smoke and energy transport from a fire. The simulations provide a wealth of information, but are computationally intensive and not suitable for parametric studies where the detailed treatment of the mass and energy transport are unnecessary. The second path extends a model previously documented at ICES meetings that attempted to predict maximum survivable fires aboard space-craft. This one-dimensional model implies the heat and mass transfer as well as toxic species production from a fire. These simplifications result in a code that is faster and more suitable for parametric studies (having already been used to help in the hatch design of the Multi-Purpose Crew Vehicle, MPCV).

FDS3 simulations of indoor hydrocarbon fires engulfing radioactive waste packages

International Nuclear Information System (INIS)

Bruecher, W.; Roewekamp, M.; Kunze, V.

2004-01-01

The thermal environment of a hypothetical large indoor hydrocarbon pool fire is more complex compared to outdoor fires and can be more severe for engulfed objects. In order to analyze potential thermal environments for interim storage of spent fuel casks or low-level radioactive waste packages engulfed in pool fires numerical simulations with the CFD fire code FDS3 were carried out for different storage configurations. In addition, data of indoor pool fire experiments were used to validate the model for this type of application. A series of pool fire experiments under different ventilation conditions and varied pool surface (1 m 2 - 4 m 2 ) inside a compartment of 3.6 m x 3.6 m x 5.7 m was conducted at iBMB (Institut fuer Baustoffe, Massivbau und Brandschutz) of Braunschweig University of Technology, Germany. The instrumentation included thermocouples, heatflux and pressure gauges, bi-directional flow probes and gas concentration measurements. A mock low-level waste drum equipped with outside and inside thermocouples was positioned as an additional heat sink near the fire source. Two of these experiments have recently been used for benchmarking a number of fire simulation codes within the International Collaborative Fire Model Project (ICFMP). FDS3 simulations by GRS of some of the above mentioned experiments will be presented showing the ability of the model to sufficiently well represent the fire environment in most cases. Further simulations were performed for hypothetical pool fire environments in interim storage facilities for German spent fuel transport and storage casks. The resulting temperature curves were then used for the thermomechanical analysis of the cask reaction performed by BAM (Bundesanstalt fuer Materialforschung und -pruefung, see corresponding conference paper by Wieser et al.). The FDS3 pool fire simulations show that the fire environment is strongly influenced by the ventilation conditions and cooling effects depending on the number and

Probabilistic methods in fire-risk analysis

International Nuclear Information System (INIS)

Brandyberry, M.D.

1989-01-01

The first part of this work outlines a method for assessing the frequency of ignition of a consumer product in a building and shows how the method would be used in an example scenario utilizing upholstered furniture as the product and radiant auxiliary heating devices (electric heaters, wood stoves) as the ignition source. Deterministic thermal models of the heat-transport processes are coupled with parameter uncertainty analysis of the models and with a probabilistic analysis of the events involved in a typical scenario. This leads to a distribution for the frequency of ignition for the product. In second part, fire-risk analysis as currently used in nuclear plants is outlines along with a discussion of the relevant uncertainties. The use of the computer code COMPBRN is discussed for use in the fire-growth analysis along with the use of response-surface methodology to quantify uncertainties in the code's use. Generalized response surfaces are developed for temperature versus time for a cable tray, as well as a surface for the hot gas layer temperature and depth for a room of arbitrary geometry within a typical nuclear power plant compartment. These surfaces are then used to simulate the cable tray damage time in a compartment fire experiment

Preliminary fire hazards analysis for W-211, Initial Tank Retrieval Systems

International Nuclear Information System (INIS)

Huckfeldt, R.A.

1995-01-01

A fire hazards analysis (FHA) was performed for Project W-211, Initial Tank Retrieval System (ITRS), at the Department of Energy (DOE) Hanford site. The objectives of this FHA was to determine (1) the fire hazards that expose the Initial Tank Retrieval System or are inherent in the process, (2) the adequacy of the fire-safety features planned, and (3) the degree of compliance of the project with specific fire safety provisions in DOE orders and related engineering codes and standards. The scope included the construction, the process hazards, building fire protection, and site wide fire protection. The results are presented in terms of the fire hazards present, the potential extent of fire damage, and the impact on employees and public safety. This study evaluated the ITRS with respect to its use at Tank 241-SY-101 only

46 CFR 28.820 - Fire pumps, fire mains, fire hydrants, and fire hoses.

Science.gov (United States)

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Fire pumps, fire mains, fire hydrants, and fire hoses... REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Aleutian Trade Act Vessels § 28.820 Fire pumps, fire mains, fire hydrants, and fire hoses. (a) Each vessel must be equipped with a self-priming, power driven fire...

Spent fuel transportation cask response to a tunnel fire scenario

Energy Technology Data Exchange (ETDEWEB)

Bajwa, C.S. [U.S. Nuclear Regulatory Commission, Washington, D.C. (United States); Adkins, H.E.; Cuta, J.M. [Pacific Northwest National Lab., Richland, WA (United States)

2004-07-01

On July 18, 2001, a freight train carrying hazardous (non-nuclear) materials derailed and caught fire while passing through the Howard Street railroad tunnel in downtown Baltimore, Maryland. The United States Nuclear Regulatory Commission (USNRC), one of the agencies responsible for ensuring the safe transportation of radioactive materials in the United States, undertook an investigation of the train derailment and fire to determine the possible regulatory implications of this particular event for the transportation of spent nuclear fuel by railroad. Shortly after the accident occurred, the USNRC met with the National Transportation Safety Board (NTSB), the U.S. agency responsible for determining the cause of transportation accidents, to discuss the details of the accident and the ensuing fire. Following these discussions, the USNRC assembled a team of experts from the National Institute of Standards and Technology (NIST), the Center for Nuclear Waste Regulatory Analyses (CNWRA), and Pacific Northwest National Laboratory (PNNL) to determine the thermal conditions that existed in the Howard Street tunnel fire and analyze the effects of this fire on various spent fuel transportation cask designs. The Fire Dynamics Simulator (FDS) code, developed by NIST, was used to determine the thermal environment present in the Howard Street tunnel during the fire. The FDS results were used as boundary conditions in the ANSYS {sup registered} and COBRA-SFS computer codes to evaluate the thermal performance of different cask designs. The staff concluded that the transportation casks analyzed would withstand a fire with thermal conditions similar to those that existed in the Baltimore tunnel fire event. No release of radioactive materials would result from exposure of the casks analyzed to such an event. This paper describes the methods and approach used for this assessment.

Spent fuel transportation cask response to a tunnel fire scenario

International Nuclear Information System (INIS)

Bajwa, C.S.; Adkins, H.E.; Cuta, J.M.

2004-01-01

On July 18, 2001, a freight train carrying hazardous (non-nuclear) materials derailed and caught fire while passing through the Howard Street railroad tunnel in downtown Baltimore, Maryland. The United States Nuclear Regulatory Commission (USNRC), one of the agencies responsible for ensuring the safe transportation of radioactive materials in the United States, undertook an investigation of the train derailment and fire to determine the possible regulatory implications of this particular event for the transportation of spent nuclear fuel by railroad. Shortly after the accident occurred, the USNRC met with the National Transportation Safety Board (NTSB), the U.S. agency responsible for determining the cause of transportation accidents, to discuss the details of the accident and the ensuing fire. Following these discussions, the USNRC assembled a team of experts from the National Institute of Standards and Technology (NIST), the Center for Nuclear Waste Regulatory Analyses (CNWRA), and Pacific Northwest National Laboratory (PNNL) to determine the thermal conditions that existed in the Howard Street tunnel fire and analyze the effects of this fire on various spent fuel transportation cask designs. The Fire Dynamics Simulator (FDS) code, developed by NIST, was used to determine the thermal environment present in the Howard Street tunnel during the fire. The FDS results were used as boundary conditions in the ANSYS registered and COBRA-SFS computer codes to evaluate the thermal performance of different cask designs. The staff concluded that the transportation casks analyzed would withstand a fire with thermal conditions similar to those that existed in the Baltimore tunnel fire event. No release of radioactive materials would result from exposure of the casks analyzed to such an event. This paper describes the methods and approach used for this assessment

Review and investigations of oscillatory flow behaviour of a horizontal ceiling opening for nuclear containment and fire safety analysis

Energy Technology Data Exchange (ETDEWEB)

Sharma, P.K.; Singh, R.K.; Ghosh, A.K. [Bhabha Atomic Research Centre, Trombay, Mumbai (India). Reactor Safety Div.

2011-05-15

In the thermal hydraulics codes developed for fire safety analysis and for containment thermal hydraulic analysis, junctions in the multi-compartment geometries is often modeled as uni-directional junctions. However, ceiling junctions are known to depict unstable/oscillatory bi-directional flow behavior. Detailed investigations have been carried out to understand the unstable flow behaviour of a junction by analyzing an earlier reported experiment and its subsequent two dimensional numerical RANS based study of fire in an enclosure. The authors attempt more realistic and desired three dimensional and inherently transient large eddy simulations using a computer code Fire Dynamics Simulator (FDS). The paper presents the details of the analysis, the results obtained and further studies required to be conducted so that the findings can be applied to the fire/containment thermal hydraulics analysis codes successfully. (orig.)

Comments on Simplified Calculation Method for Fire Exposed Concrete Columns

DEFF Research Database (Denmark)

Hertz, Kristian Dahl

1998-01-01

The author has developed new simplified calculation methods for fire exposed columns. Methods, which are found In ENV 1992-1-2 chapter 4.3 and in proposal for Danish code of Practise DS411 chapter 9. In the present supporting document the methods are derived and 50 eccentrically loaded fire expos...... columns are calculated and compared to results of full-scale tests. Furthermore 500 columns are calculated in order to present each test result related to a variation of the calculation in time of fire resistance....

UK position paper on sodium fires

Energy Technology Data Exchange (ETDEWEB)

Vaughan, G J [National Nuclear Corporation Ltd., Risley, Warrington, Cheshire (United Kingdom); Glass, D [United Kingdom Atomic Energy Authority, Dounreay Nuclear Power Development Establishment, Thurso, Caithness (United Kingdom); Newman, R N [Central Electricity Generating Board, Berekely Nuclear Laboratory, Berkeley, Gloucestershire (United Kingdom); Ramsdale, S A [United Kingdom Atomic Energy Authority, Safety and Reliability Directorate, Culcheth, Cheshire (United Kingdom); Snelling, K W [United Kingdom Atomic Energy Authority, Atomic Energy Establishment, Winfrith, Dorchester, Dorset (United Kingdom)

1989-07-01

The UK has over several years developed a philosophy for the prevention, mitigation and extinguishment of sodium fires. The systems which were developed for PFR have been continuously revised and modified and from these considerations systems were proposed for CDFR. The latest phases of this development are described with reference to the CDFR plant. The current analytical and experimental work on fires, aerosols and sodium concrete reactions is also discussed. The UK are developing codes to analyse the effects of a sodium fire in a building and to model aerosol behaviour following a fire. Experimental work on small scale fires, aerosol behaviour, filtration devices and sodium concrete reaction is being carried out on a laboratory scale. Techniques for aerosol measurement and characterisation have also been developed and used both In the laboratory and large scale tests. Larger scale tests of sodium fire extinguishment techniques have also been performed. Currently a programme of tests (SOFA) of large scale fires in the open to investigate the chemical and physical changes in the aerosol and its dispersion in the atmosphere are just beginning. The UK studies are intended to both assist in the development of prevention and mitigation systems for design base and beyond design base accidents in any building which contains sodium (or sodium potassium alloy) and also to provide methods for assessing the risks from such accidents. (author)

UK position paper on sodium fires

International Nuclear Information System (INIS)

Vaughan, G.J.; Glass, D.; Newman, R.N.; Ramsdale, S.A.; Snelling, K.W.

1989-01-01

The UK has over several years developed a philosophy for the prevention, mitigation and extinguishment of sodium fires. The systems which were developed for PFR have been continuously revised and modified and from these considerations systems were proposed for CDFR. The latest phases of this development are described with reference to the CDFR plant. The current analytical and experimental work on fires, aerosols and sodium concrete reactions is also discussed. The UK are developing codes to analyse the effects of a sodium fire in a building and to model aerosol behaviour following a fire. Experimental work on small scale fires, aerosol behaviour, filtration devices and sodium concrete reaction is being carried out on a laboratory scale. Techniques for aerosol measurement and characterisation have also been developed and used both In the laboratory and large scale tests. Larger scale tests of sodium fire extinguishment techniques have also been performed. Currently a programme of tests (SOFA) of large scale fires in the open to investigate the chemical and physical changes in the aerosol and its dispersion in the atmosphere are just beginning. The UK studies are intended to both assist in the development of prevention and mitigation systems for design base and beyond design base accidents in any building which contains sodium (or sodium potassium alloy) and also to provide methods for assessing the risks from such accidents. (author)

Oscillator Neural Network Retrieving Sparsely Coded Phase Patterns

Science.gov (United States)

Aoyagi, Toshio; Nomura, Masaki

1999-08-01

Little is known theoretically about the associative memory capabilities of neural networks in which information is encoded not only in the mean firing rate but also in the timing of firings. Particularly, in the case of sparsely coded patterns, it is biologically important to consider the timings of firings and to study how such consideration influences storage capacities and quality of recalled patterns. For this purpose, we propose a simple extended model of oscillator neural networks to allow for expression of a nonfiring state. Analyzing both equilibrium states and dynamical properties in recalling processes, we find that the system possesses good associative memory.

77 FR 67628 - National Fire Codes: Request for Public Input for Revision of Codes and Standards

Science.gov (United States)

2012-11-13

... Standard on Fire and 7/8/2013 Life Safety in Animal Housing Facilities. NFPA 160--2011 Standard for the Use... five years in Revision Cycles that begin twice each year and take approximately two years to complete. Each Revision Cycle proceeds according to a published schedule that includes final dates for all major...

Bursts generate a non-reducible spike-pattern code

Directory of Open Access Journals (Sweden)

Hugo G Eyherabide

2009-05-01

Full Text Available On the single-neuron level, precisely timed spikes can either constitute firing-rate codes or spike-pattern codes that utilize the relative timing between consecutive spikes. There has been little experimental support for the hypothesis that such temporal patterns contribute substantially to information transmission. Using grasshopper auditory receptors as a model system, we show that correlations between spikes can be used to represent behaviorally relevant stimuli. The correlations reflect the inner structure of the spike train: a succession of burst-like patterns. We demonstrate that bursts with different spike counts encode different stimulus features, such that about 20% of the transmitted information corresponds to discriminating between different features, and the remaining 80% is used to allocate these features in time. In this spike-pattern code, the "what" and the "when" of the stimuli are encoded in the duration of each burst and the time of burst onset, respectively. Given the ubiquity of burst firing, we expect similar findings also for other neural systems.

46 CFR 28.315 - Fire pumps, fire mains, fire hydrants, and fire hoses.

Science.gov (United States)

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Fire pumps, fire mains, fire hydrants, and fire hoses... After September 15, 1991, and That Operate With More Than 16 Individuals on Board § 28.315 Fire pumps, fire mains, fire hydrants, and fire hoses. (a) Each vessel 36 feet (11.8 meters) or more in length must...

Regional variation in fire weather controls the reported occurrence of Scottish wildfires

Directory of Open Access Journals (Sweden)

G. Matt Davies

2016-11-01

Full Text Available Fire is widely used as a traditional habitat management tool in Scotland, but wildfires pose a significant and growing threat. The financial costs of fighting wildfires are significant and severe wildfires can have substantial environmental impacts. Due to the intermittent occurrence of severe fire seasons, Scotland, and the UK as a whole, remain somewhat unprepared. Scotland currently lacks any form of Fire Danger Rating system that could inform managers and the Fire and Rescue Services (FRS of periods when there is a risk of increased of fire activity. We aimed evaluate the potential to use outputs from the Canadian Fire Weather Index system (FWI system to forecast periods of increased fire risk and the potential for ignitions to turn into large wildfires. We collated four and a half years of wildfire data from the Scottish FRS and examined patterns in wildfire occurrence within different regions, seasons, between urban and rural locations and according to FWI system outputs. We used a variety of techniques, including Mahalanobis distances, percentile analysis and Thiel-Sen regression, to scope the best performing FWI system codes and indices. Logistic regression showed significant differences in fire activity between regions, seasons and between urban and rural locations. The Fine Fuel Moisture Code and the Initial Spread Index did a tolerable job of modelling the probability of fire occurrence but further research on fuel moisture dynamics may provide substantial improvements. Overall our results suggest it would be prudent to ready resources and avoid managed burning when FFMC > 75 and/or ISI > 2.

Regional variation in fire weather controls the reported occurrence of Scottish wildfires.

Science.gov (United States)

Davies, G Matt; Legg, Colin J

2016-01-01

Fire is widely used as a traditional habitat management tool in Scotland, but wildfires pose a significant and growing threat. The financial costs of fighting wildfires are significant and severe wildfires can have substantial environmental impacts. Due to the intermittent occurrence of severe fire seasons, Scotland, and the UK as a whole, remain somewhat unprepared. Scotland currently lacks any form of Fire Danger Rating system that could inform managers and the Fire and Rescue Services (FRS) of periods when there is a risk of increased of fire activity. We aimed evaluate the potential to use outputs from the Canadian Fire Weather Index system (FWI system) to forecast periods of increased fire risk and the potential for ignitions to turn into large wildfires. We collated four and a half years of wildfire data from the Scottish FRS and examined patterns in wildfire occurrence within different regions, seasons, between urban and rural locations and according to FWI system outputs. We used a variety of techniques, including Mahalanobis distances, percentile analysis and Thiel-Sen regression, to scope the best performing FWI system codes and indices. Logistic regression showed significant differences in fire activity between regions, seasons and between urban and rural locations. The Fine Fuel Moisture Code and the Initial Spread Index did a tolerable job of modelling the probability of fire occurrence but further research on fuel moisture dynamics may provide substantial improvements. Overall our results suggest it would be prudent to ready resources and avoid managed burning when FFMC > 75 and/or ISI > 2.

Molecular Characterization of Syphilis in Patients in Canada: Azithromycin Resistance and Detection of Treponema pallidum DNA in Whole-Blood Samples versus Ulcerative Swabs▿

Science.gov (United States)

Martin, Irene E.; Tsang, Raymond S. W.; Sutherland, Karen; Tilley, Peter; Read, Ron; Anderson, Barbara; Roy, Colleen; Singh, Ameeta E.

2009-01-01

Although detection of Treponema pallidum DNA in whole-blood specimens of syphilis patients has been reported, it is uncertain at what stage of the disease such specimens are most suitable for the molecular diagnosis of syphilis. Also, few studies have directly compared the different gene targets for routine laboratory diagnostic usage in PCR assays. We examined 87 specimens from 68 patients attending two urban sexually transmitted disease clinics in Alberta, Canada. PCR was used to amplify the T. pallidum tpp47, bmp, and polA genes as well as a specific region of the 23S rRNA gene linked to macrolide antibiotic susceptibility. In primary syphilis cases, PCR was positive exclusively (75% sensitivity rate) in ulcerative swabs but not in blood specimens, while in secondary syphilis cases, 50% of the blood specimens were positive by PCR. Four out of 14 (28.6%) of our PCR-positive syphilis cases were found to be caused by an azithromycin-resistant strain(s). Our results confirmed that swabs from primary ulcers are the specimens of choice for laboratory diagnostic purposes. However, further research is required to determine what specimen(s) would be most appropriate for molecular investigation of syphilis in secondary and latent syphilis. PMID:19339468

Probabilistic approach relative to fire scenarios study

International Nuclear Information System (INIS)

Chabot, Jean-Luc

1998-01-01

The main objective of this thesis is to develop a calculation method of the occurring probability of the fire scenarios (detection, setting of the intervention, extinction) taking into account the size and the impact of the fire on the surroundings. This new method is called 'hybrid simulation'. It includes in a unique modelling the processing of continuous and discrete phenomenon. Moreover, to correctly represent fire scenarios, it is necessary not to take only into account the 'continuous' growing of the fire itself but of also 'discrete' events like detection, fire fighting and extinction, human behaviour and related faults. For that purpose we couple a code modelling the physical aspects of the fire to Petri nets which is able to model these 'discrete' events, this coupling consists of driving the 'continuous' model by the occurring of the 'discrete' events. This new technique which can be used to cover 'discrete' and 'continuous' events in a single calculation represents a solution to dynamic reliability calculation problems, for which there is a continuously increasing demand for analysing reliability, availability of production and maintainability of complex industrial systems. (author) [fr

Validation process of ISIS CFD software for fire simulation

International Nuclear Information System (INIS)

Lapuerta, C.; Suard, S.; Babik, F.; Rigollet, L.

2012-01-01

Fire propagation constitutes a major safety concern in nuclear facilities. In this context, IRSN is developing a CFD code, named ISIS, dedicated to fire simulations. This software is based on a coherent set of models that can be used to describe a fire in large, mechanically ventilated compartments. The system of balance equations obtained by combining these models is discretized in time using fractional step methods, including a pressure correction technique for solving hydrodynamic equations. Discretization in space combines two techniques, each proven in the relevant context: mixed finite elements for hydrodynamic equations and finite volumes for transport equations. ISIS is currently in an advanced stage of verification and validation. The results obtained for a full-scale fire test performed at IRSN are presented.

Fire hazard analysis for Plutonium Finishing Plant complex

International Nuclear Information System (INIS)

MCKINNIS, D.L.

1999-01-01

A fire hazards analysis (FHA) was performed for the Plutonium Finishing Plant (PFP) Complex at the Department of Energy (DOE) Hanford site. The scope of the FHA focuses on the nuclear facilities/structures in the Complex. The analysis was conducted in accordance with RLID 5480.7, [DOE Directive RLID 5480.7, 1/17/94] and DOE Order 5480.7A, ''Fire Protection'' [DOE Order 5480.7A, 2/17/93] and addresses each of the sixteen principle elements outlined in paragraph 9.a(3) of the Order. The elements are addressed in terms of the fire protection objectives stated in paragraph 4 of DOE 5480.7A. In addition, the FHA also complies with WHC-CM-4-41, Fire Protection Program Manual, Section 3.4 [1994] and WHC-SD-GN-FHA-30001, Rev. 0 [WHC, 1994]. Objectives of the FHA are to determine: (1) the fire hazards that expose the PFP facilities, or that are inherent in the building operations, (2) the adequacy of the fire safety features currently located in the PFP Complex, and (3) the degree of compliance of the facility with specific fire safety provisions in DOE orders, related engineering codes, and standards

Current status of sodium fire and aerosol research in Japan

International Nuclear Information System (INIS)

Himeno, Yoshiaki

1989-01-01

State-of-the-art of the research and development related to sodium fire and aerosol behaviour is presented. This paper covers the Japanese work on sodium leak, leak detector, sodium oxidation and combustion, sodium aerosol release, fire mitigation, reliabilities of the electrical instruments and the reactor components under the sodium aerosols suspended atmosphere, aerosol plugging in a leak path, and the computer codes are presented. (author)

Coding of Velocity Storage in the Vestibular Nuclei

Directory of Open Access Journals (Sweden)

Sergei B. Yakushin

2017-08-01

Full Text Available Semicircular canal afferents sense angular acceleration and output angular velocity with a short time constant of ≈4.5 s. This output is prolonged by a central integrative network, velocity storage that lengthens the time constants of eye velocity. This mechanism utilizes canal, otolith, and visual (optokinetic information to align the axis of eye velocity toward the spatial vertical when head orientation is off-vertical axis. Previous studies indicated that vestibular-only (VO and vestibular-pause-saccade (VPS neurons located in the medial and superior vestibular nucleus could code all aspects of velocity storage. A recently developed technique enabled prolonged recording while animals were rotated and received optokinetic stimulation about a spatial vertical axis while upright, side-down, prone, and supine. Firing rates of 33 VO and 8 VPS neurons were studied in alert cynomolgus monkeys. Majority VO neurons were closely correlated with the horizontal component of velocity storage in head coordinates, regardless of head orientation in space. Approximately, half of all tested neurons (46% code horizontal component of velocity in head coordinates, while the other half (54% changed their firing rates as the head was oriented relative to the spatial vertical, coding the horizontal component of eye velocity in spatial coordinates. Some VO neurons only coded the cross-coupled pitch or roll components that move the axis of eye rotation toward the spatial vertical. Sixty-five percent of these VO and VPS neurons were more sensitive to rotation in one direction (predominantly contralateral, providing directional orientation for the subset of VO neurons on either side of the brainstem. This indicates that the three-dimensional velocity storage integrator is composed of directional subsets of neurons that are likely to be the bases for the spatial characteristics of velocity storage. Most VPS neurons ceased firing during drowsiness, but the firing

Analyzing containment leakage from a sodium fire by the response surface method

International Nuclear Information System (INIS)

Person, L.W.

1978-01-01

The SPOOL-FIRE code has been used with the response surface method and a Monte Carlo simulation to study sodium fire accidents. The study provides a simple method of estimating the radioactive release via containment leakage; the sensitivity of the output consequences to the variations in the input parameters is also presented

Fire protection of safe shutdown capability at commercial nuclear power plants

International Nuclear Information System (INIS)

Sullivan, K.

1993-01-01

The comprehensive industrial safety standards and codes that exist today have evolved from lessons learned through past experience, research results, and improvements in technological capabilities. The current requirements for fire safety features of commercial nuclear power stations operated in the US are a notable example of this practice. Although fire protection has always been an important design requirement, from the aftermath of a serious fire that occurred in 1975 at the Browns Ferry plant, it was learned that the life safety and property protection concerns of the major fire insurance underwriters may not sufficiently encompass nuclear safety issues, particularly with regard to the potential for fire damage to result in the common mode failure of redundant trains of systems, and components important to the safe shutdown of the reactor. Following its investigations into the Browns Ferry fire, the Nuclear Regulatory Commission (NRC) promulgated guidance documents, which ultimately developed into mandatory regulations, necessary to assure the implementation of a fire protection program that would address nuclear safety concerns. The new criteria that evolved, contain prescriptive design features, as well as personnel and administrative requirements the Commission determined to be necessary to provide a defense-in-depth level of protection against the hazards of fire and its associated effects on safety related equipment. These criteria are primarily contained in Appendix R of Title 10 to the Code of Federal Regulations (10 CFR 50). Since 1983, various members of the Department of Nuclear Energy (DNE) at Brookhaven National Laboratory (BNL) have provided technical assistance to the Nuclear Regulatory Commission (NRC) in support of its evaluations of fire protection features implemented at commercial nuclear power stations operated in the US. This paper presents a discussion of the insights gained by the author during his active participation in this area

Calculation of the effects of a cargo fire in a hold of a ship

International Nuclear Information System (INIS)

Cole, J.K.; Koski, J.A.; Wix, S.D.

1998-01-01

To better understand shipboard fire environments, a combined experimental and computational study has been conducted at Sandia National Laboratories to define problems that could develop and to demonstrate that modern computational fluid dynamics (CFD) tools can adequately model fires in enclosed volumes. A simulated shipping cask was used as a test object (calorimeter) in this study. This paper describes the development of a computational model for a wood crib fire located in the same hold as the test object. The commercially available CFD code used was CFX, developed by Harwell Laboratory, United Kingdom. This finite volume code was selected because of its previous use in fire analyses and its ability to treat all heat transfer mechanisms (conduction, convection and thermal radiation) in a coupled manner. Comparisons are made between experimental measurements and blind computational results that is to say: no experimental data were used to make the computations. (authors)

Focus on the studies in support of fire safety analysis. IRSN modelling approach for nuclear facilities

Energy Technology Data Exchange (ETDEWEB)

Espargilliere, Julien; Meyrand, Raphael; Vinot, Thierry [Institut de Radioprotection et de Surete Nucleaire (IRSN), Fontenay-aux-Roses (France)

2015-12-15

For a fire safety analysis, in order to comply with nuclear safety goals, a nuclear fuel facility operator has to define the elements important for safety to be maintained, even in the case of a fire. One of the key points of this fire analysis is the assessment of possible fire scenarios in the facility. This paper presents the IRSN method applied to a case study to assess fire scenarios which have the most harmful effects on safety targets. The layout consists in a central room (fire cell) containing three glove boxes with radioactive material and three electrical cabinets. This room is linked to two connecting compartments (the fire cell and these two compartments define the containment cell) and then to two corridors. Each room is equipped with a mechanical ventilation system, and a pressure cascade is established from the corridors to the central room. A fire scenario was studied with fire ignition occurring in an electrical cabinet. This scenario has a set of safety goals (prevention of fire cell and containment device failure, propagation of the fire). This case study was conducted with the IRSN code SYLVIA based on two zones modelling. Safety goals were associated with key parameters and performance criteria to be fulfilled. Modelling assumptions were defined in order to maximize physical effects of the fire. Sensitivity studies were also conducted on key parameters such as oxygen limitation, equivalent-fuel definition. Eventually, a critical analysis of the code models was carried out.

General considerations on fire and explosions in a nuclear facility. Interaction with ventilation

International Nuclear Information System (INIS)

Savornin, J.

1983-05-01

After a brief survey of French regulations and documents used in defining fire and explosion precautions, a number of fires which have broken out in French nuclear power plants and their effects on ventilation are mentioned. Past or current tests and experiments in France are described, and the provisions made to create computer codes for refining fire safety analysis are presented. The regulations which have been established to reduce the risk of fire or explosion and to contain it without failure of the containment barrier provided by the ventilation system are then given [fr

Independent rate and temporal coding in hippocampal pyramidal cells.

Science.gov (United States)

Huxter, John; Burgess, Neil; O'Keefe, John

2003-10-23

In the brain, hippocampal pyramidal cells use temporal as well as rate coding to signal spatial aspects of the animal's environment or behaviour. The temporal code takes the form of a phase relationship to the concurrent cycle of the hippocampal electroencephalogram theta rhythm. These two codes could each represent a different variable. However, this requires the rate and phase to vary independently, in contrast to recent suggestions that they are tightly coupled, both reflecting the amplitude of the cell's input. Here we show that the time of firing and firing rate are dissociable, and can represent two independent variables: respectively the animal's location within the place field, and its speed of movement through the field. Independent encoding of location together with actions and stimuli occurring there may help to explain the dual roles of the hippocampus in spatial and episodic memory, or may indicate a more general role of the hippocampus in relational/declarative memory.

Gypsum plasterboards enhanced with phase change materials: A fire safety assessment using experimental and computational techniques

Directory of Open Access Journals (Sweden)

Kolaitis Dionysios I.

2013-11-01

Full Text Available Phase Change Materials (PCM can be used for thermal energy storage, aiming to enhance building energy efficiency. Recently, gypsum plasterboards with incorporated paraffin-based PCM blends have become commercially available. In the high temperature environment developed during a fire, the paraffins, which exhibit relatively low boiling points, may evaporate and, escaping through the gypsum plasterboard's porous structure, emerge to the fire region, where they may ignite, thus adversely affecting the fire resistance characteristics of the building. Aiming to assess the fire safety behaviour of such building materials, an extensive experimental and computational analysis is performed. The fire behaviour and the main thermo-physical physical properties of PCM-enhanced gypsum plasterboards are investigated, using a variety of standard tests and devices (Scanning Electron Microscopy, Thermo Gravimetric Analysis, Cone Calorimeter. The obtained results are used to develop a dedicated numerical model, which is implemented in a CFD code. CFD simulations are validated using measurements obtained in a cone calorimeter. In addition, the CFD code is used to simulate an ISO 9705 room exposed to fire conditions, demonstrating that PCM addition may indeed adversely affect the fire safety of a gypsum plasterboard clad building.

Tunnel fire testing and modeling the Morgex North tunnel experiment

CERN Document Server

Borghetti, Fabio; Gandini, Paolo; Frassoldati, Alessio; Tavelli, Silvia

2017-01-01

This book aims to cast light on all aspects of tunnel fires, based on experimental activities and theoretical and computational fluid dynamics (CFD) analyses. In particular, the authors describe a transient full-scale fire test (~15 MW), explaining how they designed and performed the experimental activity inside the Morgex North tunnel in Italy. The entire organization of the experiment is described, from preliminary evaluations to the solutions found for management of operational difficulties and safety issues. This fire test allowed the collection of different measurements (temperature, air velocity, smoke composition, pollutant species) useful for validating and improving CFD codes and for testing the real behavior of the tunnel and its safety systems during a diesel oil fire with a significant heat release rate. Finally, the fire dynamics are compared with empirical correlations, CFD simulations, and literature measurements obtained in other similar tunnel fire tests. This book will be of interest to all ...

Introduction into scientific work methods-a necessity when performance-based codes are introduced

DEFF Research Database (Denmark)

Dederichs, Anne; Sørensen, Lars Schiøtt

The introduction of performance-based codes in Denmark in 2004 requires new competences from people working with different aspects of fire safety in the industry and the public sector. This abstract presents an attempt in reducing problems with handling and analysing the mathematical methods...... and CFD models when applying performance-based codes. This is done within the educational program "Master of Fire Safety Engineering" at the department of Civil Engineering at the Technical University of Denmark. It was found that the students had general problems with academic methods. Therefore, a new...

Numerical simulation methods of fires in nuclear power plants

International Nuclear Information System (INIS)

Keski-Rahkonen, O.; Bjoerkman, J.; Heikkilae, L.

1992-01-01

Fire is a significant hazard to the safety of nuclear power plants (NPP). Fire may be serious accident as such, but even small fire at a critical point in a NPP may cause an accident much more serious than fire itself. According to risk assessments a fire may be an initial cause or a contributing factor in a large part of reactor accidents. At the Fire Technology and the the Nuclear Engineering Laboratory of the Technical Research Centre of Finland (VTT) fire safety research for NPPs has been carried out in a large extent since 1985. During years 1988-92 a project Advanced Numerical Modelling in Nuclear Power Plants (PALOME) was carried out. In the project the level of numerical modelling for fire research in Finland was improved by acquiring, preparing for use and developing numerical fire simulation programs. Large scale test data of the German experimental program (PHDR Sicherheitsprogramm in Kernforschungscentral Karlsruhe) has been as reference. The large scale tests were simulated by numerical codes and results were compared to calculations carried out by others. Scientific interaction with outstanding foreign laboratories and scientists has been an important part of the project. This report describes the work of PALOME-project carried out at the Fire Technology Laboratory only. A report on the work at the Nuclear Engineering Laboratory will be published separatively. (au)

Technical methods for a risk-informed, performance-based fire protection program at nuclear power plants

International Nuclear Information System (INIS)

Dey, M.K.

1998-01-01

This paper presents a technical review and examination of technical methods that are available for developing a risk-informed, performance-based fire protection program at a nuclear plant. The technical methods include ''engineering tools'' for examining the fire dynamics of fire protection problems, reliability techniques for establishing an optimal fire protection surveillance program, fire computer codes for analyzing important fire protection safety parameters, and risk-informed approaches that can range from drawing qualitative insights from risk information to quantifying the risk impact of alternative fire protection approaches. Based on this technical review and examination, it is concluded that methods for modeling fires, and reliability and fire PRA analyses are currently available to support the initial implementation of simple risk-informed, performance-based approaches in fire protection programs. (author)

Technical methods for a risk-informed, performance-based fire protection program at nuclear power plants

International Nuclear Information System (INIS)

Dey, M.K.

2000-01-01

This paper presents a technical review and examination of technical methods that are available for developing a risk-informed, performance-based fire protection program at a nuclear plant. The technical methods include 'engineering tools' for examining the fire dynamics of fire protection problems, reliability techniques for establishing an optimal fire protection surveillance program, fire computer codes for analyzing important fire protection safety parameters, and risk-informed approaches that can range from drawing qualitative insights from risk information to quantifying the risk impact of alternative fire protection approaches. Based on this technical review and examination, it is concluded that methods for modeling fires, and reliability and fire probabilistic risk analyses (PRA) are currently available to support the initial implementation of simple risk-informed, performance-based approaches in fire protection programs. (orig.) [de

Tech assist/fire safety assessment of 100K area facilities

International Nuclear Information System (INIS)

Johnson, B.H.

1994-01-01

This Tech Assist/Fire Safety Assessment provides a comprehensive assessment of the 100K Area Facilities at the U.S. Department of Energy's Hanford Site for fire protection upgrades that may be needed given the limited remaining service life of these facilities. This assessment considers the relative nature of observed fire risks and whether the installed fire protection systems adequately control this risk. The analysis is based on compliance with DOE Orders, NFPA Codes and Standards, and recognized industry practice. Limited remaining service life (i.e., 6 to 12 years), current value of each facility, comparison to the best protected class of industrial risk, and the potential for exemptions from DOE requirements are key factors for recommendations presented in this report

Fire hazard analysis for Plutonium Finishing Plant complex

Energy Technology Data Exchange (ETDEWEB)

MCKINNIS, D.L.

1999-02-23

A fire hazards analysis (FHA) was performed for the Plutonium Finishing Plant (PFP) Complex at the Department of Energy (DOE) Hanford site. The scope of the FHA focuses on the nuclear facilities/structures in the Complex. The analysis was conducted in accordance with RLID 5480.7, [DOE Directive RLID 5480.7, 1/17/94] and DOE Order 5480.7A, ''Fire Protection'' [DOE Order 5480.7A, 2/17/93] and addresses each of the sixteen principle elements outlined in paragraph 9.a(3) of the Order. The elements are addressed in terms of the fire protection objectives stated in paragraph 4 of DOE 5480.7A. In addition, the FHA also complies with WHC-CM-4-41, Fire Protection Program Manual, Section 3.4 [1994] and WHC-SD-GN-FHA-30001, Rev. 0 [WHC, 1994]. Objectives of the FHA are to determine: (1) the fire hazards that expose the PFP facilities, or that are inherent in the building operations, (2) the adequacy of the fire safety features currently located in the PFP Complex, and (3) the degree of compliance of the facility with specific fire safety provisions in DOE orders, related engineering codes, and standards.

Modeling fire susceptibility to delineate wildland-urban interface for municipal-scale fire risk management.

Science.gov (United States)

Whitman, Ellen; Rapaport, Eric; Sherren, Kate

2013-12-01

The wildland-urban interface (WUI) is the region where development meets and intermingles with wildlands. The WUI has an elevated fire risk due to the proximity of development and residents to wildlands with natural wildfire regimes. Existing methods of delineating WUI are typically applied over a large region, use proxies for risk, and do not consider site-specific fire hazard drivers. While these models are appropriate for federal and provincial risk management, municipal managers require models intended for smaller regions. The model developed here uses the Burn-P3 fire behavior model to model WUI from local fire susceptibility (FS) in two study communities. Forest fuel code (FFC) maps for the study communities were modified using remote sensing data to produce detailed forest edges, including ladder fuels, update data currency, and add buildings and roads. The modified FFC maps used in Burn-P3 produced bimodal FS distributions for each community. The WUI in these communities was delineated as areas within community bounds where FS was greater than or equal to -1 SD from the mean FS value ([Formula: see text]), which fell in the trough of the bimodal distribution. The WUI so delineated conformed to the definition of WUI. This model extends WUI modeling for broader risk management initiatives for municipal management of risk, as it (a) considers site-specific drivers of fire behavior; (b) models risk, represented by WUI, specific to a community; and, (c) does not use proxies for risk.

Sodium pool fires consequences on a confined vessel and on the environment

International Nuclear Information System (INIS)

Rzekiecki, R.; Charpenel, J.; Malet, J.C.; Cucinotta, A.

1989-01-01

This paper presents the PYROS I Code used in France to calculate the effects of a sodium pool fire on a vessel and his validation range. The results or the atmospheric behaviour of the aerosol are given. Predicting the consequences of large sodium fires in large cells from the results of small scaled experiments, claim attention on scale effects. (author)

Modeling of the structural response to fire of a high-rise steel building

DEFF Research Database (Denmark)

Gentili, Filippo; Giuliani, Luisa; Bontempi, Franco

2011-01-01

Observations from the tests and the real fire investigations have consistently shown that the performance of a whole steel-framed building in fire is very different from the performance of its individual members (Usmani et al, 2000). In this context, it is of interest to investigate the failures...... problems due to the triggering of local mechanism should be overcome to this purpose. In this paper, a steel structure has been considered as case study and the response of the structural system to fire and fire effects has been investigated with the avail of a finite element commercial code. These kinds...

Further evaluation of the characteristics of Treponema pallidum-specific IgM antibody in syphilis serofast reaction patients.

Science.gov (United States)

Lin, Li-Rong; Zheng, Wei-Hong; Tong, Man-Li; Fu, Zuo-Gen; Liu, Gui-Li; Fu, Jian-Guo; Zhang, Dai-Wei; Yang, Tian-Ci; Liu, Li-Li

2011-11-01

Syphilis serofast reaction (SSR) is common in clinical work. From June 2005 to May 2009, 1208 syphilis patients were chosen for research by the Xiamen Center of Clinical Laboratory in China. Serologic tests were performed with toluidine red unheated serum test (TRUST) and Treponema pallidum particle agglutination (TPPA). Then, T. pallidum-specific IgM antibody (TP-IgM) was detected with fluorescent treponemal antibody absorption (FTA-Abs) and TPPA. In this study, patients were divided into the following experimental groups according to the results of TRUST and TPPA: (1) the SSR group consisted of 411 cases with (+) TRUST and (+) TPPA, and without clinical manifestations after 1 year of recommended syphilis treatment; (2) the serum cure group, which was further subdivided into group A consisting of 251cases with (-) TRUST and (+) TPPA; (3) group B consisting of 546 cases with (-) TRUST and (-) TPPA; and (4) the blood donor control group which consisted of 100 cases. We demonstrated that a total of 136 cases (33.09%) of 411 SSR patients were TP-IgM positive by TPPA, and this percentage was markedly higher than that in serum cure group A (9.16%). FTA-Abs analyses revealed similar results. All samples in serum cure group B and the control group were TP-IgM negative, which is identical to our previous report. The present study also indicated that the TP-IgM positive rate was not significantly different among patients with different ages, genders, and clinical phases after 1 year of recommended therapy. From the total of 1208 syphilis patients, 289 were randomly selected for TP-DNA detection by fluorescence quantitative polymerase chain reaction, and the positive rate of TP-DNA was 32.53%, which was slightly higher than that of FTA-Abs TP-IgM, and no statistically significant difference by chi-square tests, indicating the TP-DNA result is preferably consistent with FTA-Abs and supporting our deduction that TP-IgM could be used as a serologic marker for the relapse and

Linking sediment-charcoal records and ecological modeling to understand causes of fire-regime change in boreal forests

Science.gov (United States)

Linda B. Brubaker; Philip E. Higuera; T. Scott Rupp; Mark A. Olson; Patricia M. Anderson; Feng Sheng. Hu

2009-01-01

Interactions between vegetation and fire have the potential to overshadow direct effects of climate change on fire regimes in boreal forests of North America. We develop methods to compare sediment-charcoal records with fire regimes simulated by an ecological model, ALFRESCO (Alaskan Frame-based Ecosystem Code) and apply these methods to evaluate potential causes of a...

Characterisation of open-door electrical cabinet fires in compartments

Energy Technology Data Exchange (ETDEWEB)

Coutin, M., E-mail: mickael.coutin@irsn.fr; Plumecocq, W.; Zavaleta, P.; Audouin, L.

2015-05-15

Highlights: • Heat release rate of electrical cabinet fire source in a vitiated atmosphere. • Experimental database for proper validation the combustible modelling, taking into account the oxygen depletion in an enclosure. • New model for complex fire source. - Abstract: The study of electrical fires is a major concern for fire safety in the industry and more particularly for fire safety in nuclear facilities. To investigate this topic, IRSN conducted a large number of real-scale experiments involving open-door electrical cabinets burning firstly under a calorimetric hood and then inside a mechanically-ventilated compartment. The main challenges are to determine accurately the heat release rate of such a complex fire source in a vitiated atmosphere and to provide an experimental database for validating properly the combustible modelling, taking into account the oxygen depletion in an enclosure. After providing a detailed description of the fire scenarios and of the experimental apparatus, this paper focuses on the characteristic stages of the cabinet fire development, essentially based on the heat release rate time evolution of the fire. The effects of the confinement, of the outlet branch location, of the ventilation management and of the fire barrier on the fire source were then investigated. The reproducibility of electrical cabinet fires is also studied. A new model for complex fire source (applied in this study for open-door electrical cabinet fires) was then developed. This model was introduced in the zone code SYLVIA and the major features of the compartment fire experiments, such as characteristic heat release rate with effect of oxygen depletion and over-pressure peak were then calculated with a rather good agreement for this complex fire source (i.e. electrical cabinet)

Introducing GFWED: The Global Fire Weather Database

Science.gov (United States)

Field, R. D.; Spessa, A. C.; Aziz, N. A.; Camia, A.; Cantin, A.; Carr, R.; de Groot, W. J.; Dowdy, A. J.; Flannigan, M. D.; Manomaiphiboon, K.;

DOE Fire Protection Handbook, Volume I

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-08-01

The Department of Energy (DOE) Fire Protection Program is delineated in a number of source documents including; the Code of Federal Regulations (CFR), DOE Policy Statements and Orders, DOE and national consensus standards (such as those promulgated by the National Fire Protection Association), and supplementary guidance, This Handbook is intended to bring together in one location as much of this material as possible to facilitate understanding and ease of use. The applicability of any of these directives to individual Maintenance and Operating Contractors or to given facilities and operations is governed by existing contracts. Questions regarding applicability should be directed to the DOE Authority Having Jurisdiction for fire safety. The information provided within includes copies of those DOE directives that are directly applicable to the implementation of a comprehensive fire protection program. They are delineated in the Table of Contents. The items marked with an asterisk (*) are included on the disks in WordPerfect 5.1 format, with the filename noted below. The items marked with double asterisks are provided as hard copies as well as on the disk. For those using MAC disks, the files are in Wordperfect 2.1 for MAC.

Fire flow water consumption in sprinklered and unsprinklered buildings an assessment of community impacts

CERN Document Server

Code Consultants, Inc.

2012-01-01

Fire Flow Water Consumption in Sprinklered and Unsprinklered Buildings offers a detailed analysis for calculating the fire water demand required in buildings with existing and non-existant sprinkler systems. The installation of automatic sprinkler systems can significantly reduce the amount of water needed during a fire, but it requires water for commissioning, inspection, testing, and maintenance (CITM). This book provides an estimate of fire water used under both fire conditions, including CITM, to allow communities to develop fire water fees for both sprinklered and unsprinklered buildings that are proportional to the anticipated fire water usage. The types of buildings analyzed include residential (family dwellings as well as those up to four stories in height), business, assembly, institutional, mercantile, and storage facilities. Water volume was studied using guidelines from the International Code Council, the National Fire Protection Association, and the Insurance Services Office. Fire Flow Water Cons...

Automatic Code Checking Applied to Fire Fighting and Panic Projects in a BIM Environment - BIMSCIP

Directory of Open Access Journals (Sweden)

Marcelo Franco Porto

2017-06-01

Full Text Available This work presents a computational implementation of an automatic conformity verification of building projects using a 3D modeling platform for BIM. This program was developed in C# language and based itself on the 9th Technical Instruction from Military Fire Brigade of the State of Minas Gerais which covers regulations of fire load in buildings and hazardous areas.

The vulcain N expert fire system

International Nuclear Information System (INIS)

Roche, A.

1989-03-01

The Institute for Nuclear Safety and Protection (IPSN) has begun work on an expert system to aid in the diagnosis of fire hazards in nuclear installations. This system is called Vulcain N and is designed as a support tool for the analyses carried out by the IPSN. Vulcain N, is based on the Vulcain expert system already developed by Bertin for its own needs and incorporates the specific rules and know-how of the IPSN experts. The development of Vulcain N began in October 1986 with the drawing up of the technical specifications, and should be completed by the end of 1988. Vulcain N brings together knowledge from a number of different domains: the locations of the combustible materials, the thermal characteristics of the combustible materials and of the walls of the room, the ventilation conditions and, finally, knowledge of fire experts concerning the development of fire. The latter covers four levels of expert knowledge: standards and their associated calculations, the simplified physics of the fire enabling more precise values to be obtained for the figures given by the standards, the rules and knowledge which enables a certain number of deductions to be made concerning the development of the fire, and a numerical simulation code which can be used to monitor the variation of certain characteristic parameters with time. For a given fire out-break scenario, Vulcain N performs diagnosis of different aspects: development of fire, effect of ventilation, emergency action possibilities, propagation hazards, etc. Owing to its flexibility, it can be used in the analysis of fire hazards to simulate a number of possible scenarios and to very rapidly deduce the essential, predominant factors. It will also be used to assist in drafting emergency procedures for application in facilities with nuclear hazards

Effect of fire-induced damage on the uniaxial strength characteristics of solid timber: A numerical study

International Nuclear Information System (INIS)

Hopkin, D J; El-Rimawi, J; Lennon, T; Silberschmidt, V V

2011-01-01

The advent of the structural Eurocodes has allowed civil engineers to be more creative in the design of structures exposed to fire. Rather than rely upon regulatory guidance and prescriptive methods engineers are now able to use such codes to design buildings on the basis of credible design fires rather than accepted unrealistic standard-fire time-temperature curves. Through this process safer and more efficient structural designs are achievable. The key development in enabling performance-based fire design is the emergence of validated numerical models capable of predicting the mechanical response of a whole building or sub-assemblies at elevated temperature. In such a way, efficiency savings have been achieved in the design of steel, concrete and composite structures. However, at present, due to a combination of limited fundamental research and restrictions in the UK National Annex to the timber Eurocode, the design of fire-exposed timber structures using numerical modelling techniques is not generally undertaken. The 'fire design' of timber structures is covered in Eurocode 5 part 1.2 (EN 1995-1-2). In this code there is an advanced calculation annex (Annex B) intended to facilitate the implementation of numerical models in the design of fire-exposed timber structures. The properties contained in the code can, at present, only be applied to standard-fire exposure conditions. This is due to existing limitations related to the available thermal properties which are only valid for standard fire exposure. In an attempt to overcome this barrier the authors have proposed a 'modified conductivity model' (MCM) for determining the temperature of timber structural elements during the heating phase of non-standard fires. This is briefly outlined in this paper. In addition, in a further study, the MCM has been implemented in a coupled thermo-mechanical analysis of uniaxially loaded timber elements exposed to non-standard fires. The finite element package DIANA was adopted

Characterization of open-cycle coal-fired MHD generators. Quarterly technical summary report No. 6, October 1--December 31, 1977. [PACKAGE code

Energy Technology Data Exchange (ETDEWEB)

Kolb, C.E.; Yousefian, V.; Wormhoudt, J.; Haimes, R.; Martinez-Sanchez, M.; Kerrebrock, J.L.

1978-01-30

Research has included theoretical modeling of important plasma chemical effects such as: conductivity reductions due to condensed slag/electron interactions; conductivity and generator efficiency reductions due to the formation of slag-related negative ion species; and the loss of alkali seed due to chemical combination with condensed slag. A summary of the major conclusions in each of these areas is presented. A major output of the modeling effort has been the development of an MHD plasma chemistry core flow model. This model has been formulated into a computer program designated the PACKAGE code (Plasma Analysis, Chemical Kinetics, And Generator Efficiency). The PACKAGE code is designed to calculate the effect of coal rank, ash percentage, ash composition, air preheat temperatures, equivalence ratio, and various generator channel parameters on the overall efficiency of open-cycle, coal-fired MHD generators. A complete description of the PACKAGE code and a preliminary version of the PACKAGE user's manual are included. A laboratory measurements program involving direct, mass spectrometric sampling of the positive and negative ions formed in a one atmosphere coal combustion plasma was also completed during the contract's initial phase. The relative ion concentrations formed in a plasma due to the methane augmented combustion of pulverized Montana Rosebud coal with potassium carbonate seed and preheated air are summarized. Positive ions measured include K/sup +/, KO/sup +/, Na/sup +/, Rb/sup +/, Cs/sup +/, and CsO/sup +/, while negative ions identified include PO/sub 3//sup -/, PO/sub 2//sup -/, BO/sub 2//sup -/, OH/sup -/, SH/sup -/, and probably HCrO/sub 3/, HMoO/sub 4//sup -/, and HWO/sub 3//sup -/. Comparison of the measurements with PACKAGE code predictions are presented. Preliminary design considerations for a mass spectrometric sampling probe capable of characterizing coal combustion plasmas from full scale combustors and flow trains are presented

Wildland fire limits subsequent fire occurrence

Science.gov (United States)

Sean A. Parks; Carol Miller; Lisa M. Holsinger; Scott Baggett; Benjamin J. Bird

2016-01-01

Several aspects of wildland fire are moderated by site- and landscape-level vegetation changes caused by previous fire, thereby creating a dynamic where one fire exerts a regulatory control on subsequent fire. For example, wildland fire has been shown to regulate the size and severity of subsequent fire. However, wildland fire has the potential to influence...

An overview of sodium-fire related studies in the UK

International Nuclear Information System (INIS)

Bilsborough, R.; Capp, P.D.; Newman, R.N.

1979-01-01

In the six years since the last Sodium Fires Specialists Meeting (Hanford, May 1972) the UKAEA and the Construction Companies, now NPC, have concentrated on the commissioning and early operation of the prototype Fast Reactor (PFR) at Dounreay Nuclear Power Development Establishment. Rig support for PFR has continued at Risley Nuclear Power Development Laboratory with effort mainly directed to engineering and heat transfer studies; the fire protection and leak detection systems used have been based on information available in 1972. Over the same period the CEGB have shown an increasing interest in the Liquid Metal Cooled Fast Reactor system with a consequent increase in research work on the subject of sodium fires. The text and appendices of this overview reflect this spread of emphasis. The ignition characteristics, burning rates and smoke release fractions of free ambient pool fires have been studied and this is described. This paper covers the following topics as well: extinguishment of sodium fires; prevention and protection; aerosols, physical chemistry and codes

An overview of sodium-fire related studies in the UK

Energy Technology Data Exchange (ETDEWEB)

Bilsborough, R [NPC, Risley, Warrington, Cheshire (United Kingdom); Capp, P D [UKAEA, Atomic Energy Establishment Winfrith, Winfrith, Dorchester, Dorset (United Kingdom); Newman, R N [CEGB, Berkely Nuclear Laboratories, Berkley, Gloucestershire (United Kingdom)

1979-03-01

In the six years since the last Sodium Fires Specialists Meeting (Hanford, May 1972) the UKAEA and the Construction Companies, now NPC, have concentrated on the commissioning and early operation of the prototype Fast Reactor (PFR) at Dounreay Nuclear Power Development Establishment. Rig support for PFR has continued at Risley Nuclear Power Development Laboratory with effort mainly directed to engineering and heat transfer studies; the fire protection and leak detection systems used have been based on information available in 1972. Over the same period the CEGB have shown an increasing interest in the Liquid Metal Cooled Fast Reactor system with a consequent increase in research work on the subject of sodium fires. The text and appendices of this overview reflect this spread of emphasis. The ignition characteristics, burning rates and smoke release fractions of free ambient pool fires have been studied and this is described. This paper covers the following topics as well: extinguishment of sodium fires; prevention and protection; aerosols, physical chemistry and codes.

Engineering judgement and bridging the fire safety gap in existing nuclear facilities

Energy Technology Data Exchange (ETDEWEB)

Qamheiah, G.; Wu, Y., E-mail: gqamheiah@plcfire.com, E-mail: dwu@plcfire.com [PLC Fire Safety Solutions, Mississauga, ON (Canada)

2014-07-01

Canadian nuclear power plants were constructed in the 1960's through the 1980's. Fire safety considerations were largely based on guidance from general building and fire codes in effect at the time. Since then, nuclear specific fire safety standards have been developed and adopted by the Regulator, increasing the expected level of fire safety in the process. Application of the standards to existing plants was largely limited to operational requirements viewed as retroactive. However, as existing facilities undergo modifications or refurbishment for the purpose of life extension, the expectation is that the design requirements of these fire safety standards also be satisfied. This creates considerable challenges for existing nuclear power plants as fire safety requirements such as those intended to assure means for safe egress, prevention of fire spread and protection of redundancy rely upon fire protection features that are inherent in the physical infrastructural design. This paper focuses on the methodology for conducting fire safety gap analyses on existing plants, and the integral role that engineering judgement plays in the development of viable and cost effective solutions to achieve the objectives of the current fire safety standards. (author)

Development of a global fire weather database for 1980–2012

OpenAIRE

R. D. Field; A. C. Spessa; N. A. Aziz; A. Camia; A. Cantin; R. Carr; W. J. de Groot; A. J. Dowdy; M. D. Flannigan; K. Manomaiphiboon; F. Pappenberger; V. Tanpipat; X. Wang

2014-01-01

The Canadian Fire Weather Index (FWI) System is the mostly widely used fire danger rating system in the world. We have developed a global database of daily, gridded FWI System calculations from 1980–2012. Input weather data were obtained from the NASA Modern Era Retrospective-Analysis for Research, and two different estimates of daily precipitation from rain gauges over land. FWI System Drought Code (DC) calculations from the gridded datasets were compared to calculations ...

Experimental measurement of a shipboard fire environment with simulated radioactive materials packages

International Nuclear Information System (INIS)

Koski, J.A.; Wix, S.D.

1996-01-01

Results from a series of eight test fires ranging in size from 2.2 to 18.8 MW conducted aboard the Coast Guard fire test ship Mayo Lykes at Mobile, Alabama are presented and discussed. Tests aboard the break-bulk type cargo ship consisted of heptane spray fires simulating engine room and galley fires, wood crib fires simulating cargo hold fires, and pool fires staged for comparison to land-based regulatory fire results. Primary instrumentation for the tests consisted of two pipe calorimeters that simulated a typical package shape for radioactive materials packages. The calorimeters were both located adjacent to the fires and on the opposite side of the cargo hold bulkhead nearest the fire. The calorimeters were constructed from 1.5 m length sections of nominal 2 foot diameter schedule 60 steel pipe. Type K thermocouples were attached at 12 locations on the circumference and ends of the calorimeter. Fire heat fluxes to the calorimeter surfaces were estimated with the use of the Sandia SODDIT inverse heat conduction code. Experimental results from all types of tests are discussed, and some comparisons are made between the environments found on the ship and those found in land-based pool fire tests

Appraisal of Passive and Active Fire Protection Systems in Student’s Accommodation

Directory of Open Access Journals (Sweden)

Ismail I.

2014-03-01

Full Text Available Fire protection systems are very important systems that must be included in buildings. They have a great significance in reducing or preventing the occurrences of fire. This paper presents an assessment of fire protection systems in student’s accommodation. Student accommodation is a particular type of building that provides shelter for students at University. In addition, it is also supposed to be an attractive environment, conducive to learning, and importantly, safe for occupation. The fire safety of occupants in a building, must be in accordance with the requirements of the building’s code. Therefore, the design of the building must comply with the Uniform Building By-Law (UBBL 1984 of Malaysia, and provide all of the required safety features. This paper describes the findings from investigations of passive and active fire protection systems installed in buildings, based on fire safety requirements, UBBL (1984.

Measurements in large pool fires with an actively cooled calorimeter

International Nuclear Information System (INIS)

Koski, J.A.; Wix, S.D.

1995-01-01

The pool fire thermal test described in Safety Series 6 published by the International Atomic Energy Agency (IAEA) or Title 10, Code of Federal Regulations, Part 71 (10CFR71) in the United States is one of the most difficult tests that a container for larger ''Type B'' quantities of nuclear materials must pass. If retests of a container are required, costly redesign and project delays can result. Accurate measurements and modeling of the pool fire environment will ultimately lower container costs by assuring that containers past the pool fire test on the first attempt. Experiments indicate that the object size or surface temperature of the container can play a role in determining local heat fluxes that are beyond the effects predicted from the simple radiative heat transfer laws. An analytical model described by Nicolette and Larson 1990 can be used to understand many of these effects. In this model a gray gas represents soot particles present in the flame structure. Close to the container surface, these soot particles are convectively and radiatively cooled and interact with incident energy from the surrounding fire. This cooler soot cloud effectively prevents some thermal radiation from reaching the container surface, reducing the surface heat flux below the value predicted by a transparent medium model. With some empirical constants, the model suggested by Nicolette and Larson can be used to more accurately simulate the pool fire environment. Properly formulated, the gray gas approaches also fast enough to be used with standard commercial computer codes to analyze shipping containers. To calibrate this type of model, accurate experimental measurements of radiative absorption coefficients, flame temperatures, and other parameters are necessary. A goal of the calorimeter measurements described here is to obtain such parameters so that a fast, useful design tool for large pool fires can be constructed

3-Dimensional numerical simulation of sodium spray fire accidents in LMFBRs

International Nuclear Information System (INIS)

Zhang Bin; Zhu Jizhou; Han Lang

2005-01-01

In order to estimate and foresee the sequence of sodium spray fires that may occur in the liquid metal cooled fast breeder reactors (LMFBRs), this paper develops a program to analyze such sodium fire accidents. The present study gives a 3-dimensional numerical analysis code for sodium spray fires. The spatial distributions of gas temperature and chemical species concentrations in the cell that sodium spray fires happened are given. This paper gives detailed explanation of combustion models and heat transfer models that applied in the program. And the calculation procedure and method in solving the fluid field are narrated in detail. Good agreements of an overall transient behavior are obtained in a sodium spray combustion test analysis. The comparison between the analytical and experimental results shows that the program presented in this paper is creditable and reasonable for simulating the sodium spray fires. (author)

FireCalc: An XML-based framework for distributed data analysis

International Nuclear Information System (INIS)

Duarte, A.S.; Santos, J.H.; Fernandes, H.; Neto, A.; Pereira, T.; Varandas, C.A.F.

2008-01-01

Requirements and specifications for Control Data Access and Communication (CODAC) systems in fusion reactors point towards flexible and modular solutions, independent from operating system and computer architecture. These concepts can also be applied to calculation and data analysis systems, where highly standardized solutions must also apply in order to anticipate long time-scales and high technology evolution changes. FireCalc is an analysis tool based on standard Extensible Markup Language (XML) technologies. Actions are described in an XML file, which contains necessary data specifications and the code or references to scripts. This is used by the user to send the analysis code and data to a server, which can be running either locally or remotely. Communications between the user and the server are performed through XML-RPC, an XML based remote procedure call, thus enabling the client and server to be coded in different computer languages. Access to the database, security procedures and calls to the code interpreter are handled through independent modules, which unbinds them from specific solutions. Currently there is an implementation of the FireCalc framework in Java, that uses the Shared Data Access System (SDAS) for accessing the ISTTOK database and the Scilab kernel for the numerical analysis

FireCalc: An XML-based framework for distributed data analysis

Energy Technology Data Exchange (ETDEWEB)

Duarte, A.S. [Associacao Euratom/IST, Centro de Fusao Nuclear, Av. Rovisco Pais P-1049-001 Lisboa (Portugal)], E-mail: andre.duarte@cfn.ist.utl.pt; Santos, J.H.; Fernandes, H.; Neto, A.; Pereira, T.; Varandas, C.A.F. [Associacao Euratom/IST, Centro de Fusao Nuclear, Av. Rovisco Pais P-1049-001 Lisboa (Portugal)

2008-04-15

Requirements and specifications for Control Data Access and Communication (CODAC) systems in fusion reactors point towards flexible and modular solutions, independent from operating system and computer architecture. These concepts can also be applied to calculation and data analysis systems, where highly standardized solutions must also apply in order to anticipate long time-scales and high technology evolution changes. FireCalc is an analysis tool based on standard Extensible Markup Language (XML) technologies. Actions are described in an XML file, which contains necessary data specifications and the code or references to scripts. This is used by the user to send the analysis code and data to a server, which can be running either locally or remotely. Communications between the user and the server are performed through XML-RPC, an XML based remote procedure call, thus enabling the client and server to be coded in different computer languages. Access to the database, security procedures and calls to the code interpreter are handled through independent modules, which unbinds them from specific solutions. Currently there is an implementation of the FireCalc framework in Java, that uses the Shared Data Access System (SDAS) for accessing the ISTTOK database and the Scilab kernel for the numerical analysis.

Introducing the Global Fire WEather Database (GFWED)

Science.gov (United States)

Field, R. D.

2015-12-01

The Canadian Fire Weather Index (FWI) System is the mostly widely used fire danger rating system in the world. We have developed a global database of daily FWI System calculations beginning in 1980 called the Global Fire WEather Database (GFWED) gridded to a spatial resolution of 0.5° latitude by 2/3° longitude. Input weather data were obtained from the NASA Modern Era Retrospective-Analysis for Research (MERRA), and two different estimates of daily precipitation from rain gauges over land. FWI System Drought Code calculations from the gridded datasets were compared to calculations from individual weather station data for a representative set of 48 stations in North, Central and South America, Europe, Russia, Southeast Asia and Australia. Agreement between gridded calculations and the station-based calculations tended to be most different at low latitudes for strictly MERRA-based calculations. Strong biases could be seen in either direction: MERRA DC over the Mato Grosso in Brazil reached unrealistically high values exceeding DC=1500 during the dry season but was too low over Southeast Asia during the dry season. These biases are consistent with those previously-identified in MERRA's precipitation and reinforce the need to consider alternative sources of precipitation data. GFWED is being used by researchers around the world for analyzing historical relationships between fire weather and fire activity at large scales, in identifying large-scale atmosphere-ocean controls on fire weather, and calibration of FWI-based fire prediction models. These applications will be discussed. More information on GFWED can be found at http://data.giss.nasa.gov/impacts/gfwed/

Impacts of the filter clogging on the behavior of a ventilation network in the event of fire

International Nuclear Information System (INIS)

Laborde, J.C.; Pourprix, M.; Lopez, M.C.; Savornin, J.

1991-01-01

One of the main roles of ventilation in a nuclear plant is to maintain dynamic containment during normal or accidental operating conditions. Among the incidents likely to affect a nuclear installation, fire is one of those which, coming from the safety standpoint, requires the greatest attention because it is one of the most probable risks. The consequences of a fire have to be analyzed not only in the room where it breaks out, but also for the entire ventilation network. To evaluate these consequences and develop strategies against fire, the Commissariat a l'Energie Atomique uses several test rigs and calculation codes by which the impact of a fire upon the sensitive points of a network can be determined. Research and development studies currently under way give priority to the clogging of High Efficiency Particulate Air filters. Beginning with polymer fires in a 85 m 3 ventilated room, the influence of filter clogging on the characteristic parameters of the associated ventilated network is highlighted. The resultant modeling study following these experiments reveals that coupling of a ventilation code with a fire code cannot be disassociated from the development of a filter clogging model. This paper also gives the first experimental results relative to the determination of the variation, according to time and mass of deposited aerosols, of the air flow resistance of a filter clogged by aerosols derived from combustion of standard polymers used in the nuclear industry (methyl acrylate polymer, polyvinyl chloride). A methodology to extend the results obtained on the clogging test rig to any ventilation network is then described

HOTSPOT Health Physics codes for the PC

Energy Technology Data Exchange (ETDEWEB)

Homann, S.G.

1994-03-01

The HOTSPOT Health Physics codes were created to provide Health Physics personnel with a fast, field-portable calculation tool for evaluating accidents involving radioactive materials. HOTSPOT codes are a first-order approximation of the radiation effects associated with the atmospheric release of radioactive materials. HOTSPOT programs are reasonably accurate for a timely initial assessment. More importantly, HOTSPOT codes produce a consistent output for the same input assumptions and minimize the probability of errors associated with reading a graph incorrectly or scaling a universal nomogram during an emergency. The HOTSPOT codes are designed for short-term (less than 24 hours) release durations. Users requiring radiological release consequences for release scenarios over a longer time period, e.g., annual windrose data, are directed to such long-term models as CAPP88-PC (Parks, 1992). Users requiring more sophisticated modeling capabilities, e.g., complex terrain; multi-location real-time wind field data; etc., are directed to such capabilities as the Department of Energy`s ARAC computer codes (Sullivan, 1993). Four general programs -- Plume, Explosion, Fire, and Resuspension -- calculate a downwind assessment following the release of radioactive material resulting from a continuous or puff release, explosive release, fuel fire, or an area contamination event. Other programs deal with the release of plutonium, uranium, and tritium to expedite an initial assessment of accidents involving nuclear weapons. Additional programs estimate the dose commitment from the inhalation of any one of the radionuclides listed in the database of radionuclides; calibrate a radiation survey instrument for ground-survey measurements; and screen plutonium uptake in the lung (see FIDLER Calibration and LUNG Screening sections).

HOTSPOT Health Physics codes for the PC

International Nuclear Information System (INIS)

Homann, S.G.

1994-03-01

The HOTSPOT Health Physics codes were created to provide Health Physics personnel with a fast, field-portable calculation tool for evaluating accidents involving radioactive materials. HOTSPOT codes are a first-order approximation of the radiation effects associated with the atmospheric release of radioactive materials. HOTSPOT programs are reasonably accurate for a timely initial assessment. More importantly, HOTSPOT codes produce a consistent output for the same input assumptions and minimize the probability of errors associated with reading a graph incorrectly or scaling a universal nomogram during an emergency. The HOTSPOT codes are designed for short-term (less than 24 hours) release durations. Users requiring radiological release consequences for release scenarios over a longer time period, e.g., annual windrose data, are directed to such long-term models as CAPP88-PC (Parks, 1992). Users requiring more sophisticated modeling capabilities, e.g., complex terrain; multi-location real-time wind field data; etc., are directed to such capabilities as the Department of Energy's ARAC computer codes (Sullivan, 1993). Four general programs -- Plume, Explosion, Fire, and Resuspension -- calculate a downwind assessment following the release of radioactive material resulting from a continuous or puff release, explosive release, fuel fire, or an area contamination event. Other programs deal with the release of plutonium, uranium, and tritium to expedite an initial assessment of accidents involving nuclear weapons. Additional programs estimate the dose commitment from the inhalation of any one of the radionuclides listed in the database of radionuclides; calibrate a radiation survey instrument for ground-survey measurements; and screen plutonium uptake in the lung (see FIDLER Calibration and LUNG Screening sections)

Large eddy simulation of a mechanically ventilated compartment fire for nuclear applications

Energy Technology Data Exchange (ETDEWEB)

Xu, Bao P. [Dalian Univ. of Technology (China). Faculty of Energy and Power Engineering; Wen, Jennifer X. [Warwick Univ. (United Kingdom). Warwick FIRE, School of Engineering

2015-12-15

This paper deals with the modelling of a mechanically ventilated compartment fire which is a commonplace in nuclear fire scenarios. An advanced Computational Fluid Dynamics (CFD) field model with a wall conjugate heat transfer treatment is proposed. It simultaneously solves the compartment fire flow and the wall heat conduction. The flow solver is based on the Large Eddy Simulation (LES) based fire simulation solver FireFOAM within the frame of open source CFD code OpenFOAM {sup registered}. An extended eddy dissipation model is used to calculate the chemical reaction rate. A soot model based on the concept of smoke point height is employed to model the soot formation and oxidation. A finite volume method is adopted to model the radiative heat transfer. The ventilation flow is modelled by a simplified Bernoulli equation neglecting the detailed information on the ventilation system. The proposed model is validated against a single room fire test with forced mechanical ventilations. The predictions are in reasonably good agreement with experimental data.

Evaluation of two automated chemiluminescence immunoassays, the LIAISON Treponema Screen and the ARCHITECT Syphilis TP, and the Treponema pallidum particle agglutination test for laboratory diagnosis of syphilis.

Science.gov (United States)

Wellinghausen, Nele; Dietenberger, Hanna

2011-08-01

Automated Treponema pallidum-specific chemi-luminescence immunoassays (CLIA) run on random-access analyzers allow for rapid diagnosis of syphilis infection. We evaluated the LIAISON Treponema Screen (LIA) and the ARCHITECT Syphilis TP (ARCH) in comparison to the Treponema pallidum particle agglutination (TPPA) test, as a screening test for syphilis. We performed a prospective study using 577 sera submitted for diagnosis of syphilis, including 318 samples from pregnant women. In addition, 42 stored sera from 32 patients with clinically and serologically characterized syphilis infection were investigated. In the prospective study, the sensitivity and specificity of LIA, ARCH, and TPPA were 100% (18/18), 100% (17/17), and 100% (18/18), and 100% (558/558), 99.8% (552/553), and 99.6% (556/558), respectively. In pregnant women, the specificity of LIA and ARCH was 100% (317/317) and of TPPA 99.7% (316/317). One sample from a child with assumed exposure to maternal antitreponemal antibodies was omitted from analysis. LIA, ARCH, and TPPA were also positive in all investigated sera from patients with known syphilis. Both automated CLIA demonstrated excellent diagnostic sensitivity and specificity when evaluated as a screening test for syphilis under routine conditions of a diagnostic laboratory. Thus, these may be used independently as an alternative to the manual TPPA screen.

A new approach to the Danish guidelines for fire protection of combustible insulation

Directory of Open Access Journals (Sweden)

Dragsted Anders

2013-11-01

Full Text Available The tendency to use thicker layers of insulation and a wider use of combustible insulation materials is identified to pose a potential risk to fire safety of buildings. A new approach to the current Danish prescriptive code on fire protection of combustible insulation is proposed as a way to meet the concern. The new approach uses the fire properties of the insulation material itself to point out the necessary protective measures. This is contrary to the most European countries were only a reaction to fire class of the façade construction as a whole is required. The basic principle is presented but more research is needed to complete the new approach.

Models of neural networks temporal aspects of coding and information processing in biological systems

CERN Document Server

Hemmen, J; Schulten, Klaus

1994-01-01

Since the appearance of Vol. 1 of Models of Neural Networks in 1991, the theory of neural nets has focused on two paradigms: information coding through coherent firing of the neurons and functional feedback. Information coding through coherent neuronal firing exploits time as a cardinal degree of freedom. This capacity of a neural network rests on the fact that the neuronal action potential is a short, say 1 ms, spike, localized in space and time. Spatial as well as temporal correlations of activity may represent different states of a network. In particular, temporal correlations of activity may express that neurons process the same "object" of, for example, a visual scene by spiking at the very same time. The traditional description of a neural network through a firing rate, the famous S-shaped curve, presupposes a wide time window of, say, at least 100 ms. It thus fails to exploit the capacity to "bind" sets of coherently firing neurons for the purpose of both scene segmentation and figure-ground segregatio...

The chronotron: a neuron that learns to fire temporally precise spike patterns.

Directory of Open Access Journals (Sweden)

Răzvan V Florian

Full Text Available In many cases, neurons process information carried by the precise timings of spikes. Here we show how neurons can learn to generate specific temporally precise output spikes in response to input patterns of spikes having precise timings, thus processing and memorizing information that is entirely temporally coded, both as input and as output. We introduce two new supervised learning rules for spiking neurons with temporal coding of information (chronotrons, one that provides high memory capacity (E-learning, and one that has a higher biological plausibility (I-learning. With I-learning, the neuron learns to fire the target spike trains through synaptic changes that are proportional to the synaptic currents at the timings of real and target output spikes. We study these learning rules in computer simulations where we train integrate-and-fire neurons. Both learning rules allow neurons to fire at the desired timings, with sub-millisecond precision. We show how chronotrons can learn to classify their inputs, by firing identical, temporally precise spike trains for different inputs belonging to the same class. When the input is noisy, the classification also leads to noise reduction. We compute lower bounds for the memory capacity of chronotrons and explore the influence of various parameters on chronotrons' performance. The chronotrons can model neurons that encode information in the time of the first spike relative to the onset of salient stimuli or neurons in oscillatory networks that encode information in the phases of spikes relative to the background oscillation. Our results show that firing one spike per cycle optimizes memory capacity in neurons encoding information in the phase of firing relative to a background rhythm.

Modeling peripheral olfactory coding in Drosophila larvae.

Directory of Open Access Journals (Sweden)

Derek J Hoare

Full Text Available The Drosophila larva possesses just 21 unique and identifiable pairs of olfactory sensory neurons (OSNs, enabling investigation of the contribution of individual OSN classes to the peripheral olfactory code. We combined electrophysiological and computational modeling to explore the nature of the peripheral olfactory code in situ. We recorded firing responses of 19/21 OSNs to a panel of 19 odors. This was achieved by creating larvae expressing just one functioning class of odorant receptor, and hence OSN. Odor response profiles of each OSN class were highly specific and unique. However many OSN-odor pairs yielded variable responses, some of which were statistically indistinguishable from background activity. We used these electrophysiological data, incorporating both responses and spontaneous firing activity, to develop a bayesian decoding model of olfactory processing. The model was able to accurately predict odor identity from raw OSN responses; prediction accuracy ranged from 12%-77% (mean for all odors 45.2% but was always significantly above chance (5.6%. However, there was no correlation between prediction accuracy for a given odor and the strength of responses of wild-type larvae to the same odor in a behavioral assay. We also used the model to predict the ability of the code to discriminate between pairs of odors. Some of these predictions were supported in a behavioral discrimination (masking assay but others were not. We conclude that our model of the peripheral code represents basic features of odor detection and discrimination, yielding insights into the information available to higher processing structures in the brain.

FIRE

International Nuclear Information System (INIS)

Brtis, J.S.; Hausheer, T.G.

1990-01-01

FIRE, a microcomputer based program to assist engineers in reviewing and documenting the fire protection impact of design changes has been developed. Acting as an electronic consultant, FIRE is designed to work with an experienced nuclear system engineer, who may not have any detailed fire protection expertise. FIRE helps the engineer to decide if a modification might adversely affect the fire protection design of the station. Since its first development, FIRE has been customized to reflect the fire protection philosophy of the Commonwealth Edison Company. That program is in early production use. This paper discusses the FIRE program in light of its being a useful application of expert system technologies in the power industry

Radiological risk associated with a fire scenario in a radioactive waste deposit

Energy Technology Data Exchange (ETDEWEB)

Domingos, E.N.; Lima, Z.R. de, E-mail: erica.ndomingos@gmail.com, E-mail: zelmolima@yahoo.com.br [Instituto de Engenharia Nuclear (PPGIEN/IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Aguiar, L.A., E-mail: aguiar.lais@gmail.com [Instituto de Radioproteção e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro-RJ (Brazil)

2017-07-01

A fire at the disposal of radioactive waste can result in significant damage, as well as serious risks to the environment and the health of the general public. The norms of CNEN (Comissão Nacional de Energia Nuclear), CNEN 2.03; CNEN 2.04 and CNEN 8.02 include fire protection regulations and have criteria and requirements that aim to prevent the occurrence, neutralize the action and minimize the effects of the fire on the radioactive and/or toxic mate-rial present in the installations. For decision making due to a fire scenario containing radioactive material, it is fundamental to have information that can allow the estimate of the dose to which the population will be submitted. This work proposes to identify the radiological risk of cancer in the respiratory system using the BEIR V model, associated with a fire scenario containing radioactive material generated in the Hotspot code. (author)

A Review of Fire Interactions and Mass Fires

Directory of Open Access Journals (Sweden)

Mark A. Finney

2011-01-01

Full Text Available The character of a wildland fire can change dramatically in the presence of another nearby fire. Understanding and predicting the changes in behavior due to fire-fire interactions cannot only be life-saving to those on the ground, but also be used to better control a prescribed fire to meet objectives. In discontinuous fuel types, such interactions may elicit fire spread where none otherwise existed. Fire-fire interactions occur naturally when spot fires start ahead of the main fire and when separate fire events converge in one location. Interactions can be created intentionally during prescribed fires by using spatial ignition patterns. Mass fires are among the most extreme examples of interactive behavior. This paper presents a review of the detailed effects of fire-fire interaction in terms of merging or coalescence criteria, burning rates, flame dimensions, flame temperature, indraft velocity, pulsation, and convection column dynamics. Though relevant in many situations, these changes in fire behavior have yet to be included in any operational-fire models or decision support systems.

A deterministric and probabilistric model for oilspill fires in nuclear power plants

International Nuclear Information System (INIS)

Karlsson, B.

1988-03-01

A deterministic and probabilistic model for oilspill fires in nuclear power plant compartments has been developed. It's objective is to predict whether certain components in the compartment will cease to function as a result of the fire and to give the probability of failure. Results are presented for several scenarios in two compartments. The model has been implimented in the computer code OSFIC, a tool for safety engineers to compare various component configurations in different compartments. (author)

Evaluation of FlaB1, FlaB2, FlaB3, and Tp0463 of Treponema pallidum for serodiagnosis of syphilis.

Science.gov (United States)

Jiang, Chuanhao; Xiao, Jinhong; Xie, Yafeng; Xiao, Yongjian; Wang, Chuan; Kuang, Xingxing; Xu, Man; Li, Ranhui; Zeng, Tiebing; Liu, Shuanquan; Yu, Jian; Zhao, Feijun; Wu, Yimou

2016-02-01

Syphilis is a multistage disease caused by the invasive spirochete Treponema pallidum subsp. pallidum, and accurate diagnosis is important for the prevention and treatment of syphilis. Here, to identify appropriate diagnostic antigens for serodiagnosis of syphilis, 6 recombinant proteins were expressed in Escherichia coli and purified, including flagellins (FlaB1 [Tp0868], FlaB2 [Tp0792], and FlaB3 [Tp0870]), Tp0463, Tp0751, and Tp1038. The sensitivities were determined by screening sera from individuals with primary (n=82), secondary (n=115), latent (n=105), and congenital (n=65) syphilis. The specificities were determined by screening sera from uninfected controls (n=30) and potentially cross-reactive infections including Lyme disease (n=30), leptospirosis (n=5), and hepatitis B (n=30). Our data showed that FlaB1, FlaB2, FlaB3, Tp0463, and Tp1038 exhibited higher overall sensitivities and specificities for detecting IgG antibody, with 95.4% and 98.9%, 92.6% and 95.8%, 95.1% and 95.8%, 92.6% and 97.9%, and 95.9% and 98.9%, respectively. In contrast, Tp0751 demonstrated only an overall sensitivity of 39.2%. For comparison, the sensitivity and specificity of Architect Syphilis TP were determined to be 98.1% and 93.7%, respectively. In addition, FlaB1, FlaB2, FlaB3, and Tp0463 demonstrated excellent performance for detecting IgM antibody in primary and congenital syphilis, with sensitivities of 76.8% and 83.1%, 72.0% and 87.7%, 74.4% and 89.2%, and 64.6% and 75.3%, respectively. These results indicate that FlaB1, FlaB2, FlaB3, and Tp0463 could be as novel diagnostic candidates for serodiagnosis of syphilis. Copyright © 2016 Elsevier Inc. All rights reserved.

FIRES: Fire Information Retrieval and Evaluation System - A program for fire danger rating analysis

Science.gov (United States)

Patricia L. Andrews; Larry S. Bradshaw

1997-01-01

A computer program, FIRES: Fire Information Retrieval and Evaluation System, provides methods for evaluating the performance of fire danger rating indexes. The relationship between fire danger indexes and historical fire occurrence and size is examined through logistic regression and percentiles. Historical seasonal trends of fire danger and fire occurrence can be...

Fire propagation equation for the explicit identification of fire scenarios in a fire PSA

International Nuclear Information System (INIS)

Lim, Ho Gon; Han, Sang Hoon; Moon, Joo Hyun

2011-01-01

When performing fire PSA in a nuclear power plant, an event mapping method, using an internal event PSA model, is widely used to reduce the resources used by fire PSA model development. Feasible initiating events and component failure events due to fire are identified to transform the fault tree (FT) for an internal event PSA into one for a fire PSA using the event mapping method. A surrogate event or damage term method is used to condition the FT of the internal PSA. The surrogate event or the damage term plays the role of flagging whether the system/component in a fire compartment is damaged or not, depending on the fire being initiated from a specified compartment. These methods usually require explicit states of all compartments to be modeled in a fire area. Fire event scenarios, when using explicit identification, such as surrogate or damage terms, have two problems: there is no consideration of multiple fire propagation beyond a single propagation to an adjacent compartment, and there is no consideration of simultaneous fire propagations in which an initiating fire event is propagated to multiple paths simultaneously. The present paper suggests a fire propagation equation to identify all possible fire event scenarios for an explicitly treated fire event scenario in the fire PSA. Also, a method for separating fire events was developed to make all fire events a set of mutually exclusive events, which can facilitate arithmetic summation in fire risk quantification. A simple example is given to confirm the applicability of the present method for a 2x3 rectangular fire area. Also, a feasible asymptotic approach is discussed to reduce the computational burden for fire risk quantification

European Model Code of safe practice in the storage and handling of petroleum products. Part I. Operations

Energy Technology Data Exchange (ETDEWEB)

1973-01-01

This safe practice code was prepared by a working group consisting of experts from 10 Western European countries. It consists of short guidelines and technical advice on general precautions, injuries and medical services, permits to work, fire prevention and fighting, jetties, pipework, storage tanks, static electricity, electrical equipment, road vehicles, tank cars, handling of bitumen products, liquefied petroleum gases, packed products and training of personnel. The code is supplemented by 10 appendices, including a suggested syllabus for a 2-day course on fire prevention and emergency action for managers of oil installations.

Use of a field model to analyze probable fire environments encountered within the complex geometries of nuclear power plants

International Nuclear Information System (INIS)

Boccio, J.L.; Usher, J.L.; Singhal, A.K.; Tam, L.T.

1985-08-01

A fire in a nuclear power plant (NPP) can damage equipment needed to safely operate the plant and thereby either directly cause an accident or else reduce the plant's margin of safety. The development of a field-model fire code to analyze the probable fire environments encountered within NPP is discussed. A set of fire tests carried out under the aegis of the US Nuclear Regulatory Commission (NRC) is described. The results of these tests are then utilized to validate the field model

Reatividade do anticorpo IgM anti-Treponema pallidum na soroconversão e na resposta sorológica ao tratamento de sífilis IgM antibody reactivity to Treponema pallidum in seroconversion and in the serologic response to syphilis treatment

Directory of Open Access Journals (Sweden)

Neuza Satomi Sato

2012-12-01

Full Text Available INTRODUÇÃO: A utilidade da detecção de anticorpos da imunoglobulina da classe M (IgM no diagnóstico da sífilis tem sido discutida há tempos. OBJETIVO: No presente estudo foi analisada a ocorrência de anticorpo IgM anti-T. pallidum (Tp-IgMAc nas amostras de pacientes com sífilis recente, na fase de soroconversão e no monitoramento da resposta sorológica pós-tratamento. MÉTODOS: Amostras séricas de 11 indivíduos. RESULTADOS: Na soroconversão, o Tp-IgMAc foi detectado nas amostras de 10 indivíduos, e em um paciente a reatividade IgM ocorreu anteriormente ao Venereal Disease Research Laboratory (VDRL. A sororreversão foi evidenciada nas amostras de três pacientes com sífilis secundária tratada, e em um indivíduo com reinfecção. CONCLUSÃO: A detecção de Tp-IgMAc mostrou ser um potencial marcador diagnóstico de sífilis ativa e o desempenho do ensaio imunoenzimático de captura de IgM (ELISA-IgM para o monitoramento pós-tratamento foi similar ao da VDRL.INTRODUCTION: The appropriateness of IgM antibody detection in the diagnosis of syphilis has been extensively discussed. OBJECTIVE: This study aimed at assessing the detection of anti-T. pallidum IgM antibody (TP-IgMAb in serum samples from patients with recent syphilis in seroconversion and in the monitoring of post-treatment serological response. METHODS: Serum samples from 11 individuals. RESULTS: At seroconversion, positive Tp-IgMAb was detected in 10 samples and IgM reactivity previous to Venereal Disease Research Laboratory (VDRL was detected in one sample. Seroreversion was found in samples from three treated patients with secondary syphilis and in one individual with reinfection. CONCLUSION: Tp-IgMAb detection proved to be a potential diagnostic marker for active syphilis, and IgM capture enzyme linked immunosorbent assay (ELISA-IgM performance was similar to VDRL in post-treatment monitoring.

Cocaine Dysregulates Opioid Gating of GABA Neurotransmission in the Ventral Pallidum

Science.gov (United States)

Scofield, Michael D.; Rice, Kenner C.; Cheng, Kejun; Roques, Bernard P.

2014-01-01

The ventral pallidum (VP) is a target of dense nucleus accumbens projections. Many of these projections coexpress GABA and the neuropeptide enkephalin, a δ and μ opioid receptor (MOR) ligand. Of these two, the MOR in the VP is known to be involved in reward-related behaviors, such as hedonic responses to palatable food, alcohol intake, and reinstatement of cocaine seeking. Stimulating MORs in the VP decreases extracellular GABA, indicating that the effects of MORs in the VP on cocaine seeking are via modulating GABA neurotransmission. Here, we use whole-cell patch-clamp on a rat model of withdrawal from cocaine self-administration to test the hypothesis that MORs presynaptically regulate GABA transmission in the VP and that cocaine withdrawal changes the interaction between MORs and GABA. We found that in cocaine-extinguished rats pharmacological activation of MORs no longer presynaptically inhibited GABA release, whereas blocking the MORs disinhibited GABA release. Moreover, MOR-dependent long-term depression of GABA neurotransmission in the VP was lost in cocaine-extinguished rats. Last, GABA neurotransmission was found to be tonically suppressed in cocaine-extinguished rats. These substantial synaptic changes indicated that cocaine was increasing tone on MOR receptors. Accordingly, increasing endogenous tone by blocking the enzymatic degradation of enkephalin inhibited GABA neurotransmission in yoked saline rats but not in cocaine-extinguished rats. In conclusion, our results indicate that following withdrawal from cocaine self-administration enkephalin levels in the VP are elevated and the opioid modulation of GABA neurotransmission is impaired. This may contribute to the difficulties withdrawn addicts experience when trying to resist relapse. PMID:24431463

Applicability of the 'constructional fire prevention for industrial plants' to power plants

International Nuclear Information System (INIS)

Hammacher, P.

1978-01-01

Power plants, especially nuclear power plants, are considered because of their high value and large construction volume to be among the most important industrial constructions of our time. They have a very exposed position from the point of view of fire prevention because of their constructional and operational concept. The efforts in the Federal Republic of Germany to standardize laws and regulations for fire prevention in industrial plants (industrial construction code, DIN 18230) must be supported if only because they would simplify the licensing procedure. However these regulations cannot be applied in many cases and especially in the main buildings of thermal power plants without restricting or even endangering the function or the safety of such plants. At the present state of the art many parts of the power plant can surely be defined as 'fire safe'. Fire endangered plant components and rooms are protected according to their importance by different measures (constructional measures, fire-fighting equipments, extractors for flue gases and for heat, fire-brigade of the plant). (orig.) [de

Response of steel box columns in fire conditions

Directory of Open Access Journals (Sweden)

Mahmood Yahyai

2017-05-01

Full Text Available Effect of elevated temperatures on the mechanical properties of steel, brings the importance of investigating the effect of fire on the steel structures anxiously. Columns, as the main load-carrying part of a structure, can be highly vulnerable to the fire. In this study, the behavior of steel gravity columns with box cross section exposed to fire has been investigated. These kinds of columns are widely used in common steel structures design in Iran. In current study, the behavior of such columns in fire conditions is investigated through the finite element method. To perform this, the finite element model of a steel column which has been previously tested under fire condition, was prepared. Experimental loading and boundary conditions were considered in the model and was analyzed. Results were validated by experimental data and various specimens of gravity box columns were designed according to the Iran’s steel buildings code, and modeled and analyzed using Abaqus software. The effect of width to thickness ratio of column plates, the load ratio and slenderness on the ultimate strength of the column was investigated, and the endurance time was estimated under ISO 834 standard fire curve. The results revealed that an increase in width to thickness ratio and load ratio leads to reduction of endurance time and the effect of width to thickness ratio on the ultimate strength of the column decreases with temperature increase.

Safety demonstration test on solvent fire in fuel reprocessing plant

International Nuclear Information System (INIS)

Nishio, Gunji; Hashimoto, Kazuichiro

1989-03-01

This report summarizes a fundamental of results obtained in the Reprocessing Plant Safety Demonstration Test Program which was performed under the contract between the Science and Technology Agency of Japan and the Japan Atomic Energy Research Institute. In this test program, a solvent fire was hypothesized, and such data were obtained as fire behavior, smoke behavior and integrity of exhaust filters in the ventilation system. Through the test results, it was confirmed that under the fire condition in hypothetical accident, the integrity of the cell and the cell ventilation system were maintained, and the safety function of the exhaust filters was maintained against the smoke loading. Analytical results by EVENT code agreed well with the present test data on the thermofluid flow in a cell ventilation system. (author)

Episodic sequence memory is supported by a theta-gamma phase code

OpenAIRE

Heusser, Andrew C.; Poeppel, David; Ezzyat, Youssef; Davachi, Lila

2016-01-01

The meaning we derive from our experiences is not a simple static extraction of the elements, but is largely based on the order in which those elements occur. Models propose that sequence encoding is supported by interactions between high and low frequency oscillations, such that elements within an experience are represented by neural cell assemblies firing at higher frequencies (i.e. gamma) and sequential order is coded by the specific timing of firing with respect to a lower frequency oscil...

United States position paper on sodium fires, design and testing

International Nuclear Information System (INIS)

Hilliard, R.K.; Johnson, R.P.

1983-01-01

The first Specialists' Meeting on sodium fire technology sponsored by the International Working Group on Fast Reactors (IWGFR) was held in Richland, Washington in 1972. The group concluded that the state-of-technology at that time was inadequate to support the growing LMFBR industry. During the second IWGFR Specialists' Meeting on sodium fires, held in Cadarache, France in 1978, a large quantity of technical information was exchanged and areas were identified where additional work was needed. Advances in several important areas of sodium fire technology have been made in the United States since that time, including improved computer codes, design of a sodium fire protection system for the CRBRP, measurement of water release from heated concrete, and testing and modeling of the sodium-concrete reaction. Research in the U.S. related to sodium fire technology is performed chiefly at the Energy Systems Group of Rockwell International (including Atomics International), the Hanford Engineering Development Laboratory (HEDL), and the Sandia National Laboratories (SNL). The work at the first two laboratories is sponsored by the U.S. Department of Energy, while that at the latter is sponsored by the U.S. Nuclear Regulatory Commission. Various aspects of sodium fire related work is also performed at several other laboratories. The current status of sodium fire technology in the U.S. is summarized in this report

Criticality and fire-fighting - Recent developments at Westinghouse, Springfields Fuels Limited

International Nuclear Information System (INIS)

Hill, D. A.; Clemson, P. D.

2009-01-01

Fire-fighting advice in criticality-controlled areas has traditionally presented unique challenges to the nuclear industry, primarily because of the introduction of moderators / reflectors from water and foam and the potential rearrangement of materials. In an actual emergency, the decision to use water-based fire extinguishing methods is best influenced by a consensus between the criticality and fire specialists as part of the emergency planning process. A recent review of the fire-fighting arrangements at the site operated by Springfields Fuels Limited (SFL) in Preston in the United Kingdom has identified that more detailed guidance may be valuable relating to the specific areas and materials at risk, particularly to highlight the degree of risk and provide guidance on the risk of criticality if water-based fire extinguishing methods were deemed necessary. This has prompted consideration of a criticality 'Fire Tag' system, consisting of colour coded markers in the area (an immediate visual indicator of both the degree of risk and the appropriate fire-fighting response) and single sheet cards (specific guidance for the areas and materials at risk), with the process supported by appropriate training. The approach is currently being trialled on a small scale, and initial feedback from personnel has been positive. (authors)

L-type calcium channels refine the neural population code of sound level

Science.gov (United States)

Grimsley, Calum Alex; Green, David Brian

2016-01-01

The coding of sound level by ensembles of neurons improves the accuracy with which listeners identify how loud a sound is. In the auditory system, the rate at which neurons fire in response to changes in sound level is shaped by local networks. Voltage-gated conductances alter local output by regulating neuronal firing, but their role in modulating responses to sound level is unclear. We tested the effects of L-type calcium channels (CaL: CaV1.1–1.4) on sound-level coding in the central nucleus of the inferior colliculus (ICC) in the auditory midbrain. We characterized the contribution of CaL to the total calcium current in brain slices and then examined its effects on rate-level functions (RLFs) in vivo using single-unit recordings in awake mice. CaL is a high-threshold current and comprises ∼50% of the total calcium current in ICC neurons. In vivo, CaL activates at sound levels that evoke high firing rates. In RLFs that increase monotonically with sound level, CaL boosts spike rates at high sound levels and increases the maximum firing rate achieved. In different populations of RLFs that change nonmonotonically with sound level, CaL either suppresses or enhances firing at sound levels that evoke maximum firing. CaL multiplies the gain of monotonic RLFs with dynamic range and divides the gain of nonmonotonic RLFs with the width of the RLF. These results suggest that a single broad class of calcium channels activates enhancing and suppressing local circuits to regulate the sensitivity of neuronal populations to sound level. PMID:27605536

The Italian National Guidelines for the fire safety of facades

Directory of Open Access Journals (Sweden)

Lamberto Mazziotti

2013-11-01

Full Text Available Traditionally, the facades' design buildings where once only focused on architectural or aesthetic purposes (in addition, of course, of whether protective issues. Nowadays, thanks to the technological development of the construction works and the use of new types of materials, the facades' design should also address fire safety related aspects. In Europe and especially in Italy – where the types of building façades are built with windows of small surface and natural stone coverings – the green building/sustainability movement has resulted in the development of new concepts in facade or curtain wall design that intended to enhance the energy efficiency of building façades. These new building surfaces are covered by extensive panelling fitted with insulating materials or by wide glass surfaces, capable of carry out the most diverse purposes including, just to name a few: energy reduction, climate comfort, recovery of electricity through photovoltaic panels that convert sunlight into electricity, large space for advertising purpose. One of the main fire safety goal for a building design is to restrict the vertical fire spread so that the smoke and flames are limited to the fire origin floor. The new building façade and curtain wall topologies could overwhelms concerns for fire safety, therefore the Italian National fire service has released a Fire Code Guideline in order to address the fire safety design for an high rise building façade. This paper aims to show the guideline contents and the related fire safety façades concerns.

Comparison of the characteristics of fire and non-fire households in the 2004-2005 survey of fire department-attended and unattended fires.

Science.gov (United States)

Greene, Michael A

2012-06-01

Comparison of characteristics of fire with non-fire households to determine factors differentially associated with fire households (fire risk factors). National household telephone survey in 2004-2005 by the US Consumer Product Safety Commission with 916 fire households and a comparison sample of 2161 non-fire households. There were an estimated 7.4 million fires (96.6% not reported to fire departments) with 130,000 injuries. Bivariate analysis and multivariate logistic regression analyses to assess differences in household characteristics. Significant factors associated with fire households were renting vs. owning (OR 1.988 pfire households with non-cooking fires (OR 1.383 p=0.0011). Single family houses were associated with non-fire households in the bivariate analysis but not in the multivariate analyses. Renting, household members under 18 years old and smokers are risk factors for unattended fires, similar to the literature for fatal and injury fires. Differences included household members over 65 years old (associated with non-fire households), college/postgraduate education (associated with fire households) and lack of significance of income. Preventing cooking fires (64% of survey incidents), smoking prevention efforts and fire prevention education for families with young children have the potential for reducing unattended fires and injuries.

Proceedings of the CSNI specialist meeting on interaction of fire and explosion with ventilation systems in nuclear facilities. Volume I

International Nuclear Information System (INIS)

1983-10-01

Separate abstracts were prepared for the papers presented in the following areas: (1) fire and explosion perspectives; (2) fire, explosion, and radioactive source terms; and (3) development and verification of codes (a) mathematical and computer simulation and (b) analytical and experimental comparisons

Technical committee meeting on evaluation of radioactive materials release and sodium fires in fast reactors

International Nuclear Information System (INIS)

1996-01-01

The objectives of the Technical Committee Meeting was to review the activities of research on radioactive materials release and sodium fires in fast reactors in each of the participating countries. It covered: out-of-pile experiments and analysis codes on source term; in-pile experiments on source term; core disruptive accidents; sodium leak experience in liquid metal fast reactors; evaluation of sodium fire; and aerosol behaviour

Technical committee meeting on evaluation of radioactive materials release and sodium fires in fast reactors

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-07-01

The objectives of the Technical Committee Meeting was to review the activities of research on radioactive materials release and sodium fires in fast reactors in each of the participating countries. It covered: out-of-pile experiments and analysis codes on source term; in-pile experiments on source term; core disruptive accidents; sodium leak experience in liquid metal fast reactors; evaluation of sodium fire; and aerosol behaviour.

R and D needs for evaluation of sodium fire consequences and aerosol behavior for DFBR

International Nuclear Information System (INIS)

Kubo, S.; Hashiguchi, Y.; Okabe, A.

1996-01-01

Sodium fire is one of the important safety issues for the liquid metal cooled fast reactor system. In order to achieve the reasonable plant cost performance, the rational countermeasures for sodium fire should be provided and the influence of sodium fire should be evaluated properly. This paper describes the principle of the safety design against sodium leak in the Demonstration Fast Breeder Reactor in Japan (DFBR). In addition, Research and Development (R and D) needs for the design of rational countermeasures against sodium fire and aerosol release are described which include the clarification of behaviors or phenomena, the accumulation of the database of the experimental parameters for the analysis codes, and the improvement of evaluation technique and method. (author)

Fires. A Joint Publication for U.S. Artillery Professionals. May-June 2011

Science.gov (United States)

2011-05-01

network using lasers that enabled them to identify, from a Bradley Fighting Vehicle, a 10-digit code that could be passed internally, but not to...generation. It’s the way of life for an entire society. It includes codes of manners, dress, language, religion, and rituals. Other important...security during a foot patrol in Arghandab District, Iraq. (Photo by SPC Breanne Pye, U.S. Army) 48 May-June 2011 • Fires PFC Isaias Rodriguez

Calculation of Fire Severity Factors and Fire Non-Suppression Probabilities For A DOE Facility Fire PRA

International Nuclear Information System (INIS)

Elicson, Tom; Harwood, Bentley; Lucek, Heather; Bouchard, Jim

2011-01-01

Over a 12 month period, a fire PRA was developed for a DOE facility using the NUREG/CR-6850 EPRI/NRC fire PRA methodology. The fire PRA modeling included calculation of fire severity factors (SFs) and fire non-suppression probabilities (PNS) for each safe shutdown (SSD) component considered in the fire PRA model. The SFs were developed by performing detailed fire modeling through a combination of CFAST fire zone model calculations and Latin Hypercube Sampling (LHS). Component damage times and automatic fire suppression system actuation times calculated in the CFAST LHS analyses were then input to a time-dependent model of fire non-suppression probability. The fire non-suppression probability model is based on the modeling approach outlined in NUREG/CR-6850 and is supplemented with plant specific data. This paper presents the methodology used in the DOE facility fire PRA for modeling fire-induced SSD component failures and includes discussions of modeling techniques for: Development of time-dependent fire heat release rate profiles (required as input to CFAST), Calculation of fire severity factors based on CFAST detailed fire modeling, and Calculation of fire non-suppression probabilities.

Building Fire Safety Audit at Faculty X, University of Indonesia, Year 2006

Directory of Open Access Journals (Sweden)

Fatma Lestari

2010-10-01

Full Text Available Fire may cause loss of life, material and valuable assets. The objective of this study is to conduct audit for fire safety and emergency response in the building at Faculty X, University of Indonesia, Depok. The audit results on the building fire safety facilities including emergency response and preparedness are then compared to the Building Code Australia (BCA and Indonesian regulation on the building fire safety (Kep.MenPU.No 10 and 11/KPTS/2000. The building selected are Building A, B, C, D, F and G. Building classification for A, B, D, F and G are classified as Class 5, while Building C is classified as Class 9b. Variable which are evaluated including emergency exit, building structure, fire alarm and detector, communication and fire warning system, evacuation procedure, portable fire extinguishers, hydrant, sprinkler, and emergency response preparedness. Results suggested that emergency exit is locked, and this is not comply to the regulation. Building structure has been complied to the regulation since it was made of concrete. Fire detector and alarm only provided in Building G, while other building is not available. There is no evacuation procedure available. Portable fire extinguisher has been available in all the building. Hydrant an sprinkler only available in building G. There is no emergency response preparedness in this faculty. In conclusion, the fire safety facilities in this faculty need to be improved.

A review of fire interactions and mass fires

Science.gov (United States)

Mark A. Finney; Sara S. McAllister

2011-01-01

The character of a wildland fire can change dramatically in the presence of another nearby fire. Understanding and predicting the changes in behavior due to fire-fire interactions cannot only be life-saving to those on the ground, but also be used to better control a prescribed fire to meet objectives. In discontinuous fuel types, such interactions may elicit fire...

Investigating the burning characteristics of electric cables used in the nuclear power plant by way of 3-D transient FDS code

Energy Technology Data Exchange (ETDEWEB)

Ferng, Y.M., E-mail: ymferng@ess.nthu.edu.t [Department of Engineering and System Science, Institute of Nuclear Engineering and Science, National Tsing Hua University, 101, Sec. 2. Kuang-Fu Rd., Hsinchu 30013, Taiwan (China); Liu, C.H. [Department of Engineering and System Science, Institute of Nuclear Engineering and Science, National Tsing Hua University, 101, Sec. 2. Kuang-Fu Rd., Hsinchu 30013, Taiwan (China)

2011-01-15

Burning characteristics of electrical cables are one of the key parameters for the fire hazard assessment of nuclear power plants (NPPs) since the cables are the essential sources of fire in the plants. A three-dimensional (3-D) transient computational fluid dynamics (CFD) code{sub F}DS is adopted in this paper to simulate these characteristics related to the cable burning. Being one of the NRC licensing fire codes, the FDS includes the thermal-hydraulic equations, the turbulence model and the chemical combustion model, etc. In order to assess the CFD fire models used in this code, a burning test using the control cable with the outer jacket of polyvinylchloride (PVC) and the inner insulation of cross-linked polyethylene (XLPE) is conducted. The measured parameters associated with the burning characteristics include the heat release rate (HRR), O{sub 2} depletion, and CO and CO{sub 2} production, etc. Except the amount of O{sub 2} consumption, the predicted transient behaviors of other parameters can reproduce the measured data. Based on the chemical combustion model in the FDS code, this discrepancy may be essentially resulted from the default value of hydrogen fraction (H{sub frac}) contained in the soot since the soot yield for the burning of PVC material is high enough that the uncertainty in the H{sub frac} value has a prominent effect on the amount of O{sub 2} consumption. This explanation can be confirmed by a benchmark calculation for simulating a burning test with the polymethylmethacrylate (PMMA) fuel of low-soot yield. The present simulation works can provide the useful information for the plant staff or the researcher as they would perform the fire hazard analysis in the NPPs using the FDS code.

Fire characteristics charts for fire behavior and U.S. fire danger rating

Science.gov (United States)

Faith Ann Heinsch; Pat Andrews

2010-01-01

The fire characteristics chart is a graphical method of presenting U.S. National Fire Danger Rating indices or primary surface or crown fire behavior characteristics. A desktop computer application has been developed to produce fire characteristics charts in a format suitable for inclusion in reports and presentations. Many options include change of scales, colors,...

On the use of the HOTSPOT code for evaluating accidents involving radioactive materials

International Nuclear Information System (INIS)

Sattinger, D.; Sarussi, R.; Tzarfati, Y.; Levinson, S.; Tshuva, A.

2004-01-01

The HOTSPOT Health Physics code was created by LLNL in order to provide Health Physics personnel with a fast, field portable calculation tool for evaluating accidents involving radioactive materials. The HOTSPOT code is a first order approximation of the radiation effects associated with the atmospheric release of radioactive materials. HOTSPOT programs are reasonably accurate for a timely initial assessment. More importantly, HOTSPOT code produce a consistent output for the same input assumptions, and minimize the probability of errors associated with reading a graph incorrectly. Four general programs, Plume, Explosion, Fire, and Resuspension, calculate a downwind assessment following the release of radioactive material resulting from a continuous or puff release, explosive release, fuel or fire, or an area contamination event. Additional programs estimate the dose commitment from inhalation of any one of the radionuclides listed in the database of radionuclides, calibrate a radiation survey instrument for ground survey measurements, and screening of alpha emitters in the Lung. We believe that the HOTSPOT code is extremely valuable in providing reasonable and reliable guidance for a diversity of application. For example, we demonstrate the release of 241 Am(20Ci) to the atmosphere

Extending the capabilities of CFD codes to assess ash related problems

DEFF Research Database (Denmark)

Kær, Søren Knudsen; Rosendahl, Lasse Aistrup; Baxter, B. B.

2004-01-01

This paper discusses the application of FLUENT? in theanalysis of grate-fired biomass boilers. A short description of theconcept used to model fuel conversion on the grate and the couplingto the CFD code is offered. The development and implementation ofa CFD-based deposition model is presented...... in the reminder of thepaper. The growth of deposits on furnace walls and super heatertubes is treated including the impact on heat transfer rates determinedby the CFD code. Based on the commercial CFD code FLUENT?,the overall model is fully implemented through the User DefinedFunctions. The model is configured...

Fire protection and fire fighting in nuclear installations

International Nuclear Information System (INIS)

1989-01-01

Fires are a threat to all technical installations. While fire protection has long been a well established conventional discipline, its application to nuclear facilities requires special considerations. Nevertheless, for a long time fire engineering has been somewhat neglected in the design and operation of nuclear installations. In the nuclear industry, the Browns Ferry fire in 1975 brought about an essential change in the attention paid to fire problems. Designers and plant operators, as well as insurance companies and regulators, increased their efforts to develop concepts and methods for reducing fire risks, not only to protect the capital investment in nuclear plants but also to consider the potential secondary effects which could lead to nuclear accidents. Although the number of fires in nuclear installations is still relatively large, their overall importance to the safety of nuclear power plants was not considered to be very high. Only more recently have probabilistic analyses changed this picture. The results may well have to be taken into account more carefully. Various aspects of fire fighting and fire protection were discussed during the Symposium, the first of its kind to be organized by the IAEA. It was convened in co-operation with several organizations working in the nuclear or fire protection fields. The intention was to gather experts from nuclear engineering areas and the conventional fire protection field at one meeting with a view to enhancing the exchange of information and experience and to presenting current knowledge on the various disciplines involved. The presentations at the meeting were subdivided into eight sessions: standards and licensing (6 papers); national fire safety practices (7 papers); fire safety by design (11 papers); fire fighting (2 papers); computer fire modeling (7 papers); fire safety in fuel center facilities (7 papers); fire testing of materials (3 papers); fire risk assessment (5 papers). A separate abstract was

Resolving vorticity-driven lateral fire spread using the WRF-Fire coupled atmosphere–fire numerical model

OpenAIRE

Simpson, C. C.; Sharples, J. J.; Evans, J. P.

2014-01-01

Fire channelling is a form of dynamic fire behaviour, during which a wildland fire spreads rapidly across a steep lee-facing slope in a direction transverse to the background winds, and is often accompanied by a downwind extension of the active flaming region and extreme pyro-convection. Recent work using the WRF-Fire coupled atmosphere-fire model has demonstrated that fire channelling can be characterised as vorticity-driven lateral fire spread (VDLS). In t...

Sensitivity Analysis on Fire Modeling of Main Control Board Fire Using Fire Dynamics Simulator

International Nuclear Information System (INIS)

Kang, Dae Il; Lim, Ho Gon

2015-01-01

In this study, sensitivity analyses for an MCB fire were performed to identify the effects on the MCR forced abandonment time according to the changes of height and number for fire initiation places. Hanul Unit 3 NPP was selected as a reference plant for this study. In this study, sensitivity analyses for an MCB fire were performed to identify the effects on the MCR forced abandonment time according to the changes of height and number of fire initiation places. A main control board (MCB) fire can cause a forced main control room (MCR) abandonment of the operators as well as the function failures or spurious operations of the control and instrumentation-related components. If the MCR cannot be habitable, a safe shutdown from outside the MCR can be achieved and maintained at an alternate shutdown panel independent from the MCR. When the fire modeling for an electrical cabinet such as an MCB was performed, its many input parameters can affect the fire simulation results. This study results showed that the decrease in the height of fire ignition place and the use of single fire ignition place in fire modeling for the propagating fire shortened MCR abandonment time

Sensitivity Analysis on Fire Modeling of Main Control Board Fire Using Fire Dynamics Simulator

Energy Technology Data Exchange (ETDEWEB)

Kang, Dae Il; Lim, Ho Gon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-10-15

In this study, sensitivity analyses for an MCB fire were performed to identify the effects on the MCR forced abandonment time according to the changes of height and number for fire initiation places. Hanul Unit 3 NPP was selected as a reference plant for this study. In this study, sensitivity analyses for an MCB fire were performed to identify the effects on the MCR forced abandonment time according to the changes of height and number of fire initiation places. A main control board (MCB) fire can cause a forced main control room (MCR) abandonment of the operators as well as the function failures or spurious operations of the control and instrumentation-related components. If the MCR cannot be habitable, a safe shutdown from outside the MCR can be achieved and maintained at an alternate shutdown panel independent from the MCR. When the fire modeling for an electrical cabinet such as an MCB was performed, its many input parameters can affect the fire simulation results. This study results showed that the decrease in the height of fire ignition place and the use of single fire ignition place in fire modeling for the propagating fire shortened MCR abandonment time.

Application of fire models for risk analysis in french nuclear power plants

International Nuclear Information System (INIS)

Brauns, P.

1989-04-01

Numerical simulations of compartment fires have been carried out in the French 900 MW and 1 300 MW nuclear power plants, to obtain quantitative data about this particular kind of risk: characteristic spreading times from one redundant electrical train to the other one, behaviour of important electrical components... The main stages of both studies were the following: selection of rooms, the location or function of which are essential for the plant safety in case of fire, on-site inspections to collect information about these rooms (amount of fuel, openings...), definition of fire scenarios, improvement of the fire model VESTA-PLUS, and, finally calculations using this computer code. The simulations have shown two major trends: i) the spreading times, without taking into account any external intervention, are always greater than half an hour, and ii) the specific design of the 1 300 MW power plants generally prevents one of the redundant train from being damaged due to a fire occurring in a room containing the other one. Examples of typical results obtained are given, showing the capability of application of the improved fire model to complex problems

Calculation of shipboard fire conditions for radioactive materials packages with the methods of computational fluid dynamics

International Nuclear Information System (INIS)

Koski, J.A.; Wix, S.D.; Cole, J.K.

1997-09-01

Shipboard fires both in the same ship hold and in an adjacent hold aboard a break-bulk cargo ship are simulated with a commercial finite-volume computational fluid mechanics code. The fire models and modeling techniques are described and discussed. Temperatures and heat fluxes to a simulated materials package are calculated and compared to experimental values. The overall accuracy of the calculations is assessed

The modelling of sodium jet fires in a global computer code - FEUMIX 3

International Nuclear Information System (INIS)

Rigollet-Pichon, L.; Malet, J.C.

1996-01-01

The purpose of the FEUMIX3 calculation programme is to study the consequences of an accidental leak of sodium circulating under pressure in a circuit composed of pipes and tanks. It mainly allows the thermal and mechanical consequences of a sodium fire accompanying the leak to be evaluated: evolution of the pressure in the room, evolution of the gas temperature, of the internal structures and walls, nature and quantities of aerosols produced in the room or released outside. FEUMIX3 uses the global approach to the sodium/oxygen reaction interfacial area. The FEUMIX3 calculation programme mainly concerns the sodium jets characterized by a Reynolds number higher than 105 for breaks with a cross section exceeding several mm 2 , a variable sodium flowrate (experimental conditions ranging from 0 to 250 kg/s) and for the time being, a sodium temperature of around 500 deg. C. FEUMIX3 moreover contains ventilation options allowing the parallel simulation of several systems (ventilation, extraction, gas leak, valves, pressure relief valves). The connection of several rooms to one another (100 maximum in the present version) is also predicted. The programme allows the interpretation of analytical experiments and the pre-calculation of demonstration experiments to be carried out. Within the framework of FR facility sizing, it supplies the data necessary to assess the integrity of the structures, of the behavior of systems and materials and the harmful effects on the outside or in the adjoining rooms. The model treats nearly all the scenario linked to a sodium leak, from ignition, including the establishment time of the jet, to the Propagation of fire and up to the extinguishment of the fire. It is even able to take into account the release of water coming from the over-heated concrete walls and to simulate the new chemical reactions of water-sodium and water-aerosols. (author)

Untuned But Not Irrelevant: The Role of Untuned Neurons In Sensory Information Coding

OpenAIRE

Zylberberg, Joel

2017-01-01

In the sensory systems, most neurons' firing rates are tuned to at least one aspect of the stimulus. Other neurons are appear to be untuned, meaning that their firing rates do not depend on the stimulus. Previous work on information coding in neural populations has ignored untuned neurons, based on the tacit assumption that they are unimportant. Recent experimental work has questioned this assumption, showing that in some circumstances, neurons with no apparent stimulus tuning can contribute ...

Fire protection

International Nuclear Information System (INIS)

Janetzky, E.

1980-01-01

Safety and fire prevention measurements have to be treated like the activities developing, planning, construction and erection. Therefore it is necessary that these measurements have to be integrated into the activities mentioned above at an early stage in order to guarantee their effectiveness. With regard to fire accidents the statistics of the insurance companies concerned show that the damage caused increased in the last years mainly due to high concentration of material. Organization of fire prevention and fire fighting, reasons of fire break out, characteristics and behaviour of fire, smoke and fire detection, smoke and heat venting, fire extinguishers (portable and stationary), construction material in presence of fire, respiratory protection etc. will be discussed. (orig./RW)

Technology for analysis of sodium pool fire characteristics

Energy Technology Data Exchange (ETDEWEB)

Kim, Byung Ho; Jeong, K C; Jeong, J Y; Kim, T J; Choi, J H; Choi, Y D; Hwang, S T

2000-09-01

Basic and detail design for medium sodium fire test facility was carried out and medium sodium fire test facility was constructed. Design data is as follows. - Test cell material : Concrete with high strength - Test cell dimension ; 48m{sup 3} (3x4x4m) - Design temp. ; 700 deg C - Operation temp. ; 530 deg C - Design pressure ; 1 bar (max.) - Dimension(Inside) : 3 x 4 x 4(m) - Test cell thickness ; 45cm - Liner plate with (Thickness : 3mm) In this study, sodium fire characteristics was analyzed and data for validation of computer code was produced. Oxygen and sodium filled in pool pan didn't burns instantly, but pool fire occurred through pre-ignition. Distribution of temperature in test cell was divided by two parts, and temperature at upper position appeared to be higher than temperature at lower position. The temperature in test cell increased with the feed of sodium. The pressure in test cell increased with the feed of sodium. When the feed of sodium was 8kg, peak pressure was 0.075 bar. Peak temperature in sodium pool appeared to be 854 deg C regardless of the feed of sodium. Decrease of 1% in oxygen concentration showed the rise of 0.036bar in pressure.

Technology for analysis of sodium pool fire characteristics

International Nuclear Information System (INIS)

Kim, Byung Ho; Jeong, K. C.; Jeong, J. Y.; Kim, T. J.; Choi, J. H.; Choi, Y. D.; Hwang, S. T.

2000-09-01

Basic and detail design for medium sodium fire test facility was carried out and medium sodium fire test facility was constructed. Design data is as follows. - Test cell material : Concrete with high strength - Test cell dimension ; 48m 3 (3x4x4m) - Design temp. ; 700 deg C - Operation temp. ; 530 deg C - Design pressure ; 1 bar (max.) - Dimension(Inside) : 3 x 4 x 4(m) - Test cell thickness ; 45cm - Liner plate with (Thickness : 3mm) In this study, sodium fire characteristics was analyzed and data for validation of computer code was produced. Oxygen and sodium filled in pool pan didn't burns instantly, but pool fire occurred through pre-ignition. Distribution of temperature in test cell was divided by two parts, and temperature at upper position appeared to be higher than temperature at lower position. The temperature in test cell increased with the feed of sodium. The pressure in test cell increased with the feed of sodium. When the feed of sodium was 8kg, peak pressure was 0.075 bar. Peak temperature in sodium pool appeared to be 854 deg C regardless of the feed of sodium. Decrease of 1% in oxygen concentration showed the rise of 0.036bar in pressure

Technology for analysis of sodium pool fire characteristics

Energy Technology Data Exchange (ETDEWEB)

Kim, Byung Ho; Jeong, K. C.; Jeong, J. Y.; Kim, T. J.; Choi, J. H.; Choi, Y. D.; Hwang, S. T

2000-09-01

Basic and detail design for medium sodium fire test facility was carried out and medium sodium fire test facility was constructed. Design data is as follows. - Test cell material : Concrete with high strength - Test cell dimension ; 48m{sup 3} (3x4x4m) - Design temp. ; 700 deg C - Operation temp. ; 530 deg C - Design pressure ; 1 bar (max.) - Dimension(Inside) : 3 x 4 x 4(m) - Test cell thickness ; 45cm - Liner plate with (Thickness : 3mm) In this study, sodium fire characteristics was analyzed and data for validation of computer code was produced. Oxygen and sodium filled in pool pan didn't burns instantly, but pool fire occurred through pre-ignition. Distribution of temperature in test cell was divided by two parts, and temperature at upper position appeared to be higher than temperature at lower position. The temperature in test cell increased with the feed of sodium. The pressure in test cell increased with the feed of sodium. When the feed of sodium was 8kg, peak pressure was 0.075 bar. Peak temperature in sodium pool appeared to be 854 deg C regardless of the feed of sodium. Decrease of 1% in oxygen concentration showed the rise of 0.036bar in pressure.

Protection against syphilis correlates with specificity of antibodies to the variable regions of Treponema pallidum repeat protein K.

Science.gov (United States)

Morgan, Cecilia A; Lukehart, Sheila A; Van Voorhis, Wesley C

2003-10-01

Syphilis has been recognized as a disease since the late 1400s, yet there is no practical vaccine available. One impediment to the development of a vaccine is the lack of understanding of multiple reinfections in humans despite the development of robust immune responses during the first episode. It has been shown that the Treponema pallidum repeat protein K (TprK) differs in seven discrete variable (V) regions in isolates and that the antibody response during infection is directed to these V regions. Immunization with TprK confers significant protection against infection with the homologous strain. We hypothesize that the antigenic diversity of TprK is involved in immune evasion, which contributes to the lack of heterologous protection. Here, using the rabbit model, we show a correlation between limited heterologous protection and tprK diversity in the challenge inoculum. We demonstrate that antibody responses to the V regions of one TprK molecule show limited cross-reactivity with heterologous TprK V regions.

Study on the Performance of a Proposed Fire Safe Elevator System used for Evacuation in Supertall Buildings

Directory of Open Access Journals (Sweden)

Cai Na

2016-01-01

Full Text Available Long evacuation time is a key fire safety concern when a supertall building is on fire. The elevator system can be an effective alternative. The performance of a design of fire safe elevator system combining the refuge place with fire safe elevator is studied. An example building based on this proposed design is considered. Smoke spread to the system is studied by the Computational Fluid Dynamics (CFD code Fire Dynamics Simulator (FDS. Different arrangements of smoke extraction with pressurization systems are evaluated by analysing the smoke dispersion and pressure distributions in this fire safe elevator system. Numerical results were compared with that by theoretical equations. The results show that a smoke extraction system with a four-floor approach pressurization system can be an efficient method for smoke control in elevator system for supertall buildings.

Evidence of fuels management and fire weather influencing fire severity in an extreme fire event.

Science.gov (United States)

Lydersen, Jamie M; Collins, Brandon M; Brooks, Matthew L; Matchett, John R; Shive, Kristen L; Povak, Nicholas A; Kane, Van R; Smith, Douglas F

2017-10-01

Following changes in vegetation structure and pattern, along with a changing climate, large wildfire incidence has increased in forests throughout the western United States. Given this increase, there is great interest in whether fuels treatments and previous wildfire can alter fire severity patterns in large wildfires. We assessed the relative influence of previous fuels treatments (including wildfire), fire weather, vegetation, and water balance on fire-severity in the Rim Fire of 2013. We did this at three different spatial scales to investigate whether the influences on fire severity changed across scales. Both fuels treatments and previous low to moderate-severity wildfire reduced the prevalence of high-severity fire. In general, areas without recent fuels treatments and areas that previously burned at high severity tended to have a greater proportion of high-severity fire in the Rim Fire. Areas treated with prescribed fire, especially when combined with thinning, had the lowest proportions of high severity. The proportion of the landscape burned at high severity was most strongly influenced by fire weather and proportional area previously treated for fuels or burned by low to moderate severity wildfire. The proportion treated needed to effectively reduce the amount of high severity fire varied by spatial scale of analysis, with smaller spatial scales requiring a greater proportion treated to see an effect on fire severity. When moderate and high-severity fire encountered a previously treated area, fire severity was significantly reduced in the treated area relative to the adjacent untreated area. Our results show that fuels treatments and low to moderate-severity wildfire can reduce fire severity in a subsequent wildfire, even when burning under fire growth conditions. These results serve as further evidence that both fuels treatments and lower severity wildfire can increase forest resilience. © 2017 by the Ecological Society of America.

Fire exposed facades: Numerical modelling of the LEPIR2 testing facility

Directory of Open Access Journals (Sweden)

Dréan Virginie

2016-01-01

Full Text Available LEPIR2 testing facility is aimed to evaluate the fire behaviour of construction solutions implemented on facade according with the experimental evaluation required by the French Technical Specification 249 (IT249 of the safety regulation. It aims to limit the risks of fire spreading by facades to upper levels. This facility involves a wood crib fire in the lower compartment of a full scale two levels high structure. Flames are coming outside from the compartment through windows openings and develop in front of the facade. Computational fluids dynamics simulations are carried out with the FDS code (Fire Dynamics Simulator for two full-scale experiments performed by Efectis France laboratory. The first objective of this study is to evaluate the ability of numerical model to reproduce quantitative results in terms of gas temperatures and heat flux on the tested facade for further evaluation of fire performances of an insulation solution. When experimental results are compared with numerical calculations, good agreement is found out for every quantities and each test. The proposed models for wood cribs and geometry give correct thermal loads and flames shape near the tested facade.

Benchmarking MARS (accident management software) with the Browns Ferry fire

International Nuclear Information System (INIS)

Dawson, S.M.; Liu, L.Y.; Raines, J.C.

1992-01-01

The MAAP Accident Response System (MARS) is a userfriendly computer software developed to provide management and engineering staff with the most needed insights, during actual or simulated accidents, of the current and future conditions of the plant based on current plant data and its trends. To demonstrate the reliability of the MARS code in simulatng a plant transient, MARS is being benchmarked with the available reactor pressure vessel (RPV) pressure and level data from the Browns Ferry fire. The MRS software uses the Modular Accident Analysis Program (MAAP) code as its basis to calculate plant response under accident conditions. MARS uses a limited set of plant data to initialize and track the accidnt progression. To perform this benchmark, a simulated set of plant data was constructed based on actual report data containing the information necessary to initialize MARS and keep track of plant system status throughout the accident progression. The initial Browns Ferry fire data were produced by performing a MAAP run to simulate the accident. The remaining accident simulation used actual plant data

Fire hazard analysis for WWER nuclear power plants. Report of the IAEA extrabudgetary programme on the safety of WWER nuclear power plants

International Nuclear Information System (INIS)

1994-12-01

This status report presents an overview of the different techniques available to carry out a fire hazard analysis, from qualitative criteria to quantitative methodologies of different purposes and basis; and then, it details a simplified methodology based on a screening approach which could be used in former Soviet designed nuclear power plants. The methodology presented in this report is an adequate means to identify fire related plant specific vulnerabilities to severe accidents, and it provides a useful tool for ranking the various plant fires according to their significances, as well as technical basis for prioritizing the implementation of plant improvements. The applicability of the methodology proposed to the former Soviet Union designed reactors has been evaluated. Its usefulness to the purpose defined above is conclusive. However, some aspects need further consideration, among others data sources and screening criteria. Computer codes for studying fire effects and fire spread in plant locations are also dealt with. Some computer codes are shortly described, from simplified models to more complex ones which allow more accurate modelling of geometries and accounting for additional phenomena. 10 refs, 5 tabs

Laboratory fire behavior measurements of chaparral crown fire

Science.gov (United States)

C. Sanpakit; S. Omodan; D. Weise; M Princevac

2015-01-01

In 2013, there was an estimated 9,900 wildland fires that claimed more than 577,000 acres of land. That same year, about 542 prescribed fires were used to treat 48,554 acres by several agencies in California. Being able to understand fires using laboratory models can better prepare individuals to combat or use fires. Our research focused on chaparral crown fires....

Investigation of effect of stopping supply flow into the cell on the confinement of the radioactive materials under fire accident

International Nuclear Information System (INIS)

Abe, Hitoshi; Watanabe, Koji

1999-03-01

On November 20th 1997, a fire accident happened at Uranium Enrichment Research Laboratory, Tokai, Japan Atomic Energy Research Institute and ventilation filters in the laboratory clogged. When fire accident occurs in a controlled area, a large quantity of smoke generates in the area and dropping exhaust flow from the area by the clogging of ventilation filters and rising pressure in the area are caused. Moreover, leakage of smoke including radioactive materials from the area by the pressure rising is expected. To prevent the leakage, it is expected that stopping supply flow to the area during a fire accident is effective, however, quantitative evaluation about this effect has not been performed. By using CELVA-1D code, one-dimensional thermofluid analysis code, this effect is evaluated quantitatively by modeling the laboratory and estimating source terms released during the fire accident. As the results, it has been found that the efficiency of confinement of the radioactive materials into the area is preserved in the slightly long period of time in case of stopping supply flow to the area, however, this effect can be neglected in case that scale of fire accident is relatively large. (author)

Wildland fire in ecosystems: effects of fire on flora

Science.gov (United States)

James K. Brown; Jane Kapler Smith

2000-01-01

VOLUME 2: This state-of-knowledge review about the effects of fire on flora and fuels can assist land managers with ecosystem and fire management planning and in their efforts to inform others about the ecological role of fire. Chapter topics include fire regime classification, autecological effects of fire, fire regime characteristics and postfire plant community...

Final Report. An Integrated Partnership to Create and Lead the Solar Codes and Standards Working Group

Energy Technology Data Exchange (ETDEWEB)

Rosenthal, Andrew [New Mexico State Univ., Las Cruces, NM (United States)

2013-12-30

The DOE grant, “An Integrated Partnership to Create and Lead the Solar Codes and Standards Working Group,” to New Mexico State University created the Solar America Board for Codes and Standards (Solar ABCs). From 2007 – 2013 with funding from this grant, Solar ABCs identified current issues, established a dialogue among key stakeholders, and catalyzed appropriate activities to support the development of codes and standards that facilitated the installation of high quality, safe photovoltaic systems. Solar ABCs brought the following resources to the PV stakeholder community; Formal coordination in the planning or revision of interrelated codes and standards removing “stove pipes” that have only roofing experts working on roofing codes, PV experts on PV codes, fire enforcement experts working on fire codes, etc.; A conduit through which all interested stakeholders were able to see the steps being taken in the development or modification of codes and standards and participate directly in the processes; A central clearing house for new documents, standards, proposed standards, analytical studies, and recommendations of best practices available to the PV community; A forum of experts that invites and welcomes all interested parties into the process of performing studies, evaluating results, and building consensus on standards and code-related topics that affect all aspects of the market; and A biennial gap analysis to formally survey the PV community to identify needs that are unmet and inhibiting the market and necessary technical developments.

Physics Analysis of the FIRE Experiment

International Nuclear Information System (INIS)

Jardin, S.C.; Kessel, C.E.; Meade, D.; Breslau, J.; Fu, G.; Gorelenkov, N.; Manickam, J.; Park, W.; Strauss, H.

2002-01-01

An integrated model of a complete discharge in the FIRE experiment has been developed based on the TSC simulation code. The complete simulation model includes a choice of several models for core transport, combined with an edge pedestal model and the Porcelli sawtooth model. Burn control is provided by feedback on the auxiliary heating power. We find that with the GLF23 and MMM95 transport models, Q >10 operation should be possible for H-mode pedestal temperatures in the range of 4-5 keV

Numerical modelling of a straw-fired grate boiler

DEFF Research Database (Denmark)

Kær, Søren Knudsen

2004-01-01

The paper presents a computational fluid dynamics (CFD) analysis of a 33 MW straw-fired grate boiler. Combustion on the grate plays akey-role in the analysis of these boilers and in this work a stand-alone code was used to provide inlet conditions for the CFD analysis. Modelpredictions were compa...... mixing in the furnace is a key issue leading to these problems. q 2003 Elsevier Ltd. All rights reserved....

ANALYSIS OF Treponema pallidum RECOMBINANT ANTIGENS FOR DIAGNOSIS OF SYPHILIS BY WESTERN BLOTTING TECHNIQUE Análise de antígenos recombinantes de Treponema pallidum no diagnóstico da sífilis utilizando a técnica de Western Blotting

Directory of Open Access Journals (Sweden)

Neuza Satomi SATO

1999-03-01

Full Text Available Three GST fusion recombinant antigen of Treponema pallidum, described as GST-rTp47, GST-rTp17 and GST-rTp15 were analyzed by Western blotting techniques. We have tested 53 serum samples: 25 from patients at different clinical stages of syphilis, all of them presenting anti-treponemal antibody, 25 from healthy blood donors and three from patients with sexually transmitted disease (STD other than syphilis. Almost all samples from patients with syphilis presented a strong reactivity with GST-rTp17 antigen. Some samples were non-reactive or showed a weak reaction with GST-rTp47 and/or GST-rTp15, and apparently there was no correlation with the stage of disease. There was no seropositivity among blood donors. No sample reacted with purified GST. We concluded that due to their specificity these recombinant antigens can be used as GST fusion protein for development of syphilis diagnostic assays.Os antígenos recombinantes de Treponema pallidum GST-rTp47, GST-rTp17 e GST-rTp15, produzidos em fusão com glutationa S-transferase (GST em E. coli, foram analisados quanto ao potencial diagnóstico da sífilis pela técnica de Western blotting. Foram testadas 53 amostras, sendo 25 de pacientes em diferentes estágios clínicos da sífilis, com resultados positivos no teste treponêmico clássico; 25 amostras procedentes de doadores de banco de sangue, com sorologia negativa e 3 de pacientes com doença sexualmente transmissível não relacionado à sífilis. Todas as amostras de pacientes com sífilis apresentaram alta reatividade com o antígeno GST-rTp17. Quanto aos antígenos GST-rTp47 e GST-Tp15 verificou-se uma variação na presença ou na intensidade da reação em diferentes amostras de pacientes com sífilis, sem mostrar correlação com o estágio da doença. Nenhuma reatividade contra quaisquer desses antígenos foi observada com as amostras do grupo controle. Nenhuma das amostras testadas apresentaram reatividade com a GST purificada. A

Investigations of bi-directional flow behaviour in presence of a large vertical opening in a fire compartment

International Nuclear Information System (INIS)

Sharma, Pavan K.; Gera, B.

2011-01-01

In the complex thermal hydraulics codes developed for fire, reactor and containment safety the junctions in the multi-compartment geometries are often modeled as uni-directional junctions and some construct of flow coefficient. However, certain large size junctions are known to depict bi-directional flow behaviour under specific circumstances. The CFD based computer code FDS was used for an earlier reported study of fire in an enclosure on the bidirectional flow behaviour in present of a wall opening. Numerical simulation is directed to monitor the entrainment of the fresh air from outside to the fire compartment and resulting plume deflection due to presence of a big opening. The paper presents the details of the analysis, the results obtained, and comparison with the reported experimental data in terms of plume deflection, entrainment. Detailed investigations have been carried out to understand the bi-directionality of a junction by analyzing studying the outgoing hot air flow and incoming cold air. (orig.)

The importance of fire simulation in fire prediction

Directory of Open Access Journals (Sweden)

Jevtić Radoje B.

2014-01-01

Full Text Available The appearance of fire in objects with lot of humans inside represents very possible real situation that could be very danger and could cause destructive consequences on human lives and material properties. Very important influence in fire prediction, fire protection, human and material properties safety could be a fire simulation in object. This simulation could give many useful information of possible fire propagation; possible and existed evacuation routes; possible and exited placing of fire, smoke, temperature conditions in object and many other information of crucial importance for human lives and material properties, such as the best places for sensors position, optimal number of sensors, projection of possible evacuation routes etc. There are many different programs for fire simulation. This paper presents complete fire simulation in Electrotechnical school Nikola Tesla in Niš in FDS.

Safety demonstration tests of postulated solvent fire accidents in extraction process of a fuel reprocessing plant, (2)

International Nuclear Information System (INIS)

Tukamoto, Michio; Takada, Junichi; Koike, Tadao; Nishio, Gunji; Uno, Seiichiro; Kamoshida, Atsusi; Watanabe, Hironori; Hashimoto, Kazuichiro; Kitani, Susumu.

1992-03-01

Demonstration tests of hypothetical solvent fire in an extraction process of the reprocessing plant were carried out from 1984 to 1985 in JAERI, focusing on the confinement of radioactive materials during the fire by a large-scale fire facility (FFF) to evaluate the safety of air-ventilation system in the plant. Fire data from the demonstration test were obtained by focusing on fire behavior at cells and ducts in the ventilation system, smoke generation during the fire, transport and deposition of smoke containing simulated radioactive species in the ventilation system, confinement of radioactive materials, and integrity of HEPA filters by using the FFF simulating an air-ventilation system of the reference reprocessing plant in Japan. The present report is published in a series of the report Phase I (JAERI-M 91-145) of the demonstration test. Test results in the report will be used for the verification of a computer code FACE to evaluate the safety of postulated fire accidents in the reprocessing plant. (author)

SSS: A code for computing one dimensional shock and detonation wave propagation

International Nuclear Information System (INIS)

Sun Chengwei

1986-01-01

The one-dimensional hydrodynamic code SSS for shock and detonation wave propagation in inert and reactive media is described. The elastic-plastic-hydrodynamic model and four burn techniques (the Arrhenius law, C-J volume, sharp shock and Forest Fire) are used. There are HOM and JWL options for the state equation of detonation products. Comparing with the SIN code published by LANL, the SSS code has several new options: laser effects, blast waves, diverging and instantaneous detonation waves with arbitrary initiation positions. Two examples are given to compare the SSS and SIN calculations with the experimental data

Adsorber fires

International Nuclear Information System (INIS)

Holmes, W.

1987-01-01

The following conclusions are offered with respect to activated charcoal filter systems in nuclear power plants: (1) The use of activated charcoal in nuclear facilities presents a potential for deep-seated fires. (2) The defense-in-depth approach to nuclear fire safety requires that if an ignition should occur, fires must be detected quickly and subsequently suppressed. (3) Deep-seated fires in charcoal beds are difficult to extinguish. (4) Automatic water sprays can be used to extinguish fires rapidly and reliably when properly introduced into the burning medium. The second part of the conclusions offered are more like challenges: (1) The problem associated with inadvertent actuations of fire protection systems is not a major one, and it can be reduced further by proper design review, installation, testing, and maintenance. Eliminating automatic fire extinguishing systems for the protection of charcoal adsorbers is not justified. (2) Removal of automatic fire protection systems due to fear of inadvertent fire protection system operation is a case of treating the effect rather than the cause. On the other hand, properly maintaining automatic fire protection systems will preserve the risk of fire loss at acceptable levels while at the same time reducing the risk of damage presented by inadvertent operation of fire protection systems

Molecular variation at a candidate gene implicated in the regulation of fire ant social behavior.

Directory of Open Access Journals (Sweden)

Dietrich Gotzek

2007-11-01

Full Text Available The fire ant Solenopsis invicta and its close relatives display an important social polymorphism involving differences in colony queen number. Colonies are headed by either a single reproductive queen (monogyne form or multiple queens (polygyne form. This variation in social organization is associated with variation at the gene Gp-9, with monogyne colonies harboring only B-like allelic variants and polygyne colonies always containing b-like variants as well. We describe naturally occurring variation at Gp-9 in fire ants based on 185 full-length sequences, 136 of which were obtained from S. invicta collected over much of its native range. While there is little overall differentiation between most of the numerous alleles observed, a surprising amount is found in the coding regions of the gene, with such substitutions usually causing amino acid replacements. This elevated coding-region variation may result from a lack of negative selection acting to constrain amino acid replacements over much of the protein, different mutation rates or biases in coding and non-coding sequences, negative selection acting with greater strength on non-coding than coding regions, and/or positive selection acting on the protein. Formal selection analyses provide evidence that the latter force played an important role in the basal b-like lineages coincident with the emergence of polygyny. While our data set reveals considerable paraphyly and polyphyly of S. invicta sequences with respect to those of other fire ant species, the b-like alleles of the socially polymorphic species are monophyletic. An expanded analysis of colonies containing alleles of this clade confirmed the invariant link between their presence and expression of polygyny. Finally, our discovery of several unique alleles bearing various combinations of b-like and B-like codons allows us to conclude that no single b-like residue is completely predictive of polygyne behavior and, thus, potentially causally

Morphological alterations in the caudate, putamen, pallidum and thalamus in Parkinson’s disease.

Directory of Open Access Journals (Sweden)

Amanmeet eGarg

2015-03-01

Full Text Available Like many neurodegenerative diseases, the clinical symptoms of Parkinson’s disease (PD do not manifest until significant progression of the disease has already taken place, motivating the need for sensitive biomarkers of the disease. While structural imaging is a potentially attractive method due to its widespread availability and non-invasive nature, global morphometric measures (e.g. volume have proven insensitive to subtle disease change. Here we use individual surface displacements from deformations of an average surface model to capture disease related changes in shape of the subcortical structures in Parkinson’s disease. Data were obtained from both the University of British Columbia (UBC (n=54 healthy controls (HC & n=55 Parkinson’s disease (PD patients and the publicly available Parkinson’s Progression Marker’s Initiative (PPMI(n=137(HC & n=189 (PD database. A high dimensional non-rigid registration algorithm was used to register target segmentation labels (caudate, putamen, pallidum and thalamus to a set of segmentation labels defined on the average-template. The vertex-wise surface displacements were significantly different between PD and HC in thalamic and caudate structures. However overall displacements did not correlate with disease severity, as assessed by the Unified Parkinson's Disease Rating Scale (UPDRS. The results from this study suggest disease-relevant shape abnormalities can be robustly detected in subcortical structures in Parkinson’s disease. Future studies will be required to determine if shape changes in subcortical structures are seen in the prodromal phases of the disease.

State-of-the-art review of sodium fire analysis and current notions for improvements

International Nuclear Information System (INIS)

Tasi, S.S.

1978-01-01

Sodium releases from postulated pipe ruptures, as well as failures of sodium handling equipment in liquid metal fast breeder reactors, may lead to substantial pressure-temperature transients in the sodium system cells, as well as in the reactor containment building. Sodium fire analyses are currently performed with analytical tools, such as the SPRAY, SOMIX, SPOOL-FIRE and SOFIRE-II codes. A review and evaluation of the state-of-the-art in sodium fire analysis is presented, and suggestions for further improvements are made. This work is based, in part, on studies made at Brookhaven National Laboratory during the past several years in the areas of model development and improvement associated with the accident analyses of LMFBRs

Risk assessment of main control board fire using fire dynamics simulator

Energy Technology Data Exchange (ETDEWEB)

Kang, Dae Il, E-mail: dikang@kaeri.re.kr [KAERI, 1045 Daedeokdaero, Yuseong-Gu, Daejeon 305-353 (Korea, Republic of); Kim, Kilyoo; Jang, Seung-Cheol [KAERI, 1045 Daedeokdaero, Yuseong-Gu, Daejeon 305-353 (Korea, Republic of); Yoo, Seong Yeon [Chungnam National University, 79, Daehagro, Yuseong-Gu, Daejeon (Korea, Republic of)

2015-08-15

Highlights: • A decision tree for evaluating the risk of a main control board (MCB) fire was proposed to systematically determine the MCB fire scenarios. • Fire simulations using fire dynamics simulator (FDS) were performed to estimate the time to MCR abandonment. • Non-propagating and propagating fire scenarios were considered for fire simulations. • The current study indicates that the quantification of the MCB fire risk should address the propagating fire and non-propagating fire scenarios if the MCB has no internal barriers between the panels. - Abstract: This paper presents the process and results of a risk assessment for a main control board (MCB) fire using fire dynamics simulator (FDS). A decision tree for evaluating the risk of a MCB fire was proposed to systematically determine the MCB fire scenarios, and fire simulations using FDS were performed to estimate the time to MCR abandonment. As a reference NPP for this study, Hanul unit 3 in Korea was selected and its core damage frequency (CDF) owing to the MCB fire was quantified. Two types of fire scenarios were considered for fire simulations: non-propagating fire scenarios occurring within a single MCB panel and propagating fire scenarios spreading from one control panel to the adjacent panels. Further, the fire scenarios were classified into fires with and without a heating, ventilation, and air conditioning system (HVACS). The fire simulation results showed that the major factor causing the MCR evacuation was the optical density irrelevant to the availability of the HVACS. The risk assessment results showed that the abandonment fire scenario risk was less than the non-abandonment fire scenario risk and the propagating fire scenario risk was greater than the non-propagating fire scenario risk.

Risk assessment of main control board fire using fire dynamics simulator

International Nuclear Information System (INIS)

Kang, Dae Il; Kim, Kilyoo; Jang, Seung-Cheol; Yoo, Seong Yeon

2015-01-01

Highlights: • A decision tree for evaluating the risk of a main control board (MCB) fire was proposed to systematically determine the MCB fire scenarios. • Fire simulations using fire dynamics simulator (FDS) were performed to estimate the time to MCR abandonment. • Non-propagating and propagating fire scenarios were considered for fire simulations. • The current study indicates that the quantification of the MCB fire risk should address the propagating fire and non-propagating fire scenarios if the MCB has no internal barriers between the panels. - Abstract: This paper presents the process and results of a risk assessment for a main control board (MCB) fire using fire dynamics simulator (FDS). A decision tree for evaluating the risk of a MCB fire was proposed to systematically determine the MCB fire scenarios, and fire simulations using FDS were performed to estimate the time to MCR abandonment. As a reference NPP for this study, Hanul unit 3 in Korea was selected and its core damage frequency (CDF) owing to the MCB fire was quantified. Two types of fire scenarios were considered for fire simulations: non-propagating fire scenarios occurring within a single MCB panel and propagating fire scenarios spreading from one control panel to the adjacent panels. Further, the fire scenarios were classified into fires with and without a heating, ventilation, and air conditioning system (HVACS). The fire simulation results showed that the major factor causing the MCR evacuation was the optical density irrelevant to the availability of the HVACS. The risk assessment results showed that the abandonment fire scenario risk was less than the non-abandonment fire scenario risk and the propagating fire scenario risk was greater than the non-propagating fire scenario risk

Means of evaluating the consequences of a fire in ventilation and filtration networks

International Nuclear Information System (INIS)

Laborde, J.C.; Mulcey, P.; Pourprix, M.; Savornin, J.; Tessier, J.

1989-10-01

Accident events involving fire are quite frequent and could have a severe effect on the safety of nuclear facilities. As confinement must be maintained, the ventilation and filtration systems have to be designed to exclude any radioactive release to the environment. To determine and analyse the consequences of a fire on the ventilation network and on its associated air cleaning systems, a research program including the development of calculation codes and experimental studies has been carried out at the Nuclear Studies Centre at Saclay (France). The paper describes the highlights of this research program

BPACK -- A computer model package for boiler reburning/co-firing performance evaluations. User`s manual, Volume 1

Energy Technology Data Exchange (ETDEWEB)

Wu, K.T.; Li, B.; Payne, R.

1992-06-01

This manual presents and describes a package of computer models uniquely developed for boiler thermal performance and emissions evaluations by the Energy and Environmental Research Corporation. The model package permits boiler heat transfer, fuels combustion, and pollutant emissions predictions related to a number of practical boiler operations such as fuel-switching, fuels co-firing, and reburning NO{sub x} reductions. The models are adaptable to most boiler/combustor designs and can handle burner fuels in solid, liquid, gaseous, and slurried forms. The models are also capable of performing predictions for combustion applications involving gaseous-fuel reburning, and co-firing of solid/gas, liquid/gas, gas/gas, slurry/gas fuels. The model package is conveniently named as BPACK (Boiler Package) and consists of six computer codes, of which three of them are main computational codes and the other three are input codes. The three main codes are: (a) a two-dimensional furnace heat-transfer and combustion code: (b) a detailed chemical-kinetics code; and (c) a boiler convective passage code. This user`s manual presents the computer model package in two volumes. Volume 1 describes in detail a number of topics which are of general users` interest, including the physical and chemical basis of the models, a complete description of the model applicability, options, input/output, and the default inputs. Volume 2 contains a detailed record of the worked examples to assist users in applying the models, and to illustrate the versatility of the codes.

Fire-Walking

Science.gov (United States)

Willey, David

2010-01-01

This article gives a brief history of fire-walking and then deals with the physics behind fire-walking. The author has performed approximately 50 fire-walks, took the data for the world's hottest fire-walk and was, at one time, a world record holder for the longest fire-walk (www.dwilley.com/HDATLTW/Record_Making_Firewalks.html). He currently…

Forest-fire models

Science.gov (United States)

Haiganoush Preisler; Alan Ager

2013-01-01

For applied mathematicians forest fire models refer mainly to a non-linear dynamic system often used to simulate spread of fire. For forest managers forest fire models may pertain to any of the three phases of fire management: prefire planning (fire risk models), fire suppression (fire behavior models), and postfire evaluation (fire effects and economic models). In...

Fire Perimeters

Data.gov (United States)

California Natural Resource Agency — The Fire Perimeters data consists of CDF fires 300 acres and greater in size and USFS fires 10 acres and greater throughout California from 1950 to 2003. Some fires...

Fire History

Data.gov (United States)

California Natural Resource Agency — The Fire Perimeters data consists of CDF fires 300 acres and greater in size and USFS fires 10 acres and greater throughout California from 1950 to 2002. Some fires...

Methods and criteria for evaluation of nuclear reactor fire protection alternatives and modifications

International Nuclear Information System (INIS)

Levinson, S.H.

1982-01-01

The objective of this work is to develop a methodology for the evaluation of a fire protection system in a nuclear power plant and demonstrate the feasibility of encoding this method in a computer program. A Monte Carlo simulation has been developed; it is divided into the four phases of a fire scenario: ignition, detection, suppression and propagation. The ignition model consists of probabilistically determining at what location within the zone a fire will occur. The detection model is divided into two components. THe first is the automatic detection model, which calculates the fire's physical symptoms and compares them against the threshold values of the detectors specified for the zone to determine a time-to-detection. The second part is the human detection model; this evaluates the time required for a human to observe and report a fire. If detection is successful, the suppression mode determines if the fire is effectively extinguished, and if so, the time required to do so. This model is also divided into an automatic and human component. The propagation model is embedded in a deterministic, control-volume computer code which calculates the fire scenario history. A computer program, FIRES, is described which supports the developed models. FIRES is an interactive graphics package providing a simple means of establishing the many input parameters. In addition to allowing parameter values to be easily set or modified, the graphics provides a convenient display mode for the results of a simulation

Electronic firing systems and methods for firing a device

Science.gov (United States)

Frickey, Steven J [Boise, ID; Svoboda, John M [Idaho Falls, ID

2012-04-24

An electronic firing system comprising a control system, a charging system, an electrical energy storage device, a shock tube firing circuit, a shock tube connector, a blasting cap firing circuit, and a blasting cap connector. The control system controls the charging system, which charges the electrical energy storage device. The control system also controls the shock tube firing circuit and the blasting cap firing circuit. When desired, the control system signals the shock tube firing circuit or blasting cap firing circuit to electrically connect the electrical energy storage device to the shock tube connector or the blasting cap connector respectively.

78 FR 24725 - National Fire Codes: Request for Public Input for Revision of Codes and Standards

Science.gov (United States)

2013-04-26

... Production, Storage, and Handling of Liquefied Natural Gas (LNG). NFPA 61--2013 Standard for the 7/6/2015... Nitrate Film. NFPA 51--2013 Standard for the Design 7/6/2015 and Installation of Oxygen-Fuel Gas Systems... Charging Plants. NFPA 52--2013 Vehicular Gaseous Fuel 1/3/2014 Systems Code. NFPA 53--2011 Recommended...

Fire weather conditions and fire-atmosphere interactions observed during low-intensity prescribed fires - RxCADRE 2012

Science.gov (United States)

Craig B. Clements; Neil P. Lareau; Daisuke Seto; Jonathan Contezac; Braniff Davis; Casey Teske; Thomas J. Zajkowski; Andrew T. Hudak; Benjamin C. Bright; Matthew B. Dickinson; Bret W. Butler; Daniel Jimenez; J. Kevin. Hiers

2016-01-01

The role of fire-atmosphere coupling on fire behaviour is not well established, and to date few field observations have been made to investigate the interactions between fire spread and fire-induced winds. Therefore, comprehensive field observations are needed to better understand micrometeorological aspects of fire spread. To address this need, meteorological...

Community participation in fire management planning: The Trinity county fire safe council's fire plan

Science.gov (United States)

Yvonne Everett

2008-01-01

In 1999, Trinity County CA, initiated a participatory fire management planning effort. Since that time, the Trinity County Fire Safe Council has completed critical portions of a fire safe plan and has begun to implement projects defined in the plan. Completion of a GIS based, landscape scale fuels reduction element in the plan defined by volunteer fire fighters, agency...

Managing wildland fires: integrating weather models into fire projections

Science.gov (United States)

Anne M. Rosenthal; Francis Fujioka

2004-01-01

Flames from the Old Fire sweep through lands north of San Bernardino during late fall of 2003. Like many Southern California fires, the Old Fire consumed susceptible forests at the urban-wildland interface and spread to nearby city neighborhoods. By incorporating weather models into fire perimeter projections, scientist Francis Fujioka is improving fire modeling as a...

Enhancing adaptive capacity for restoring fire-dependent ecosystems: the Fire Learning Network's Prescribed Fire Training Exchanges

Directory of Open Access Journals (Sweden)

Andrew G. Spencer

2015-09-01

Full Text Available Prescribed fire is a critical tool for promoting restoration and increasing resilience in fire-adapted ecosystems, but there are barriers to its use, including a shortage of personnel with adequate ecological knowledge and operational expertise to implement prescribed fire across multijurisdictional landscapes. In the United States, recognized needs for both professional development and increased use of fire are not being met, often because of institutional limitations. The Fire Learning Network has been characterized as a multiscalar, collaborative network that works to enhance the adaptive capacity of fire management institutions, and this network developed the Prescribed Fire Training Exchanges (TREXs to address persistent challenges in increasing the capacity for prescribed fire implementation. Our research was designed to investigate where fire professionals face professional barriers, how the TREX addresses these, and in what ways the TREX may be contributing to the adaptive capacity of fire management institutions. We evaluated the training model using surveys, interviews, focus groups, and participant observation. We found that, although the training events cannot overcome all institutional barriers, they incorporate the key components of professional development in fire; foster collaboration, learning, and network building; and provide flexible opportunities with an emphasis on local context to train a variety of professionals with disparate needs. The strategy also offers an avenue for overcoming barriers faced by contingent and nonfederal fire professionals in attaining training and operational experience, thereby increasing the variety of actors and resources involved in fire management. Although it is an incremental step, the TREX is contributing to the adaptive capacity of institutions in social-ecological systems in which fire is a critical ecological process.

Computer codes for level 1 probabilistic safety assessment

International Nuclear Information System (INIS)

1990-06-01

Probabilistic Safety Assessment (PSA) entails several laborious tasks suitable for computer codes assistance. This guide identifies these tasks, presents guidelines for selecting and utilizing computer codes in the conduct of the PSA tasks and for the use of PSA results in safety management and provides information on available codes suggested or applied in performing PSA in nuclear power plants. The guidance is intended for use by nuclear power plant system engineers, safety and operating personnel, and regulators. Large efforts are made today to provide PC-based software systems and PSA processed information in a way to enable their use as a safety management tool by the nuclear power plant overall management. Guidelines on the characteristics of software needed for management to prepare a software that meets their specific needs are also provided. Most of these computer codes are also applicable for PSA of other industrial facilities. The scope of this document is limited to computer codes used for the treatment of internal events. It does not address other codes available mainly for the analysis of external events (e.g. seismic analysis) flood and fire analysis. Codes discussed in the document are those used for probabilistic rather than for phenomenological modelling. It should be also appreciated that these guidelines are not intended to lead the user to selection of one specific code. They provide simply criteria for the selection. Refs and tabs

US Fire Administration Fire Statistics

Data.gov (United States)

Department of Homeland Security — The U.S. Fire Administration collects data from a variety of sources to provide information and analyses on the status and scope of the fire problem in the United...

Fire safety of historical buildings traditional versus innovative “behavioural design” solutions by using wayfinding systems

CERN Document Server

Bernardini, Gabriele

2017-01-01

This book applies a behavioral point of view to individuals’ fire safety in historic buildings. It outlines theoretical and operative issues, based on recent studies and international guidelines. Firstly, critical issues for Building Heritage fire safety are widely discussed, by including the modelling of human factor and man-environment-fire interference in these architectural spaces. A significant part of the book includes a discussion on emergency modeling and simulation. A source code for representing the fire evacuation process (including man-evacuation facilities interactions) is offered to the reader. Methods for effectiveness assessment of risk-reducing solutions are provided and tested in a case-study. Being a structured approach to occupants-related problems during a fire in heritage buildings, it offers an innovative methodology and practical examples that researchers and designers can use as a guide when proposing and testing solutions. Evaluation indexes for effectiveness assessment (also usefu...

Experimental study of fire barriers preventing vertical fire spread in ETISs

Directory of Open Access Journals (Sweden)

Xin Huang

2013-11-01

Full Text Available In recent years, the external thermal insulation system (ETIS has been applied increasingly in a large amount of buildings for energy conservation purpose. However, the increase use of combustible insulation materials in the ETIS has raised serious fire safety problems. Fires involving this type of ETIS have caused severe damage and loss. In order to improve its fire safety, fire barriers were suggested to be installed. This paper introduces fire experiments that have been done to study the effects of fire barriers on preventing vertical fire spread along the ETIS. The experiments were performed according to BS 8414-1:2002 “Fire performance of external cladding systems – Part 1: Test method for non-loadbearing external cladding systems applied to the face of the building”. The test facility consists of a 9 m high wall. The fire sources were wood cribs with a fire size of 3 ± 0.5 MW. The insulation materials were expanded polystyrene foam (EPS. The fire barrier was a horizontal strip of rockwool with a width of 300 mm. Thermocouples were used to measure temperatures outside and inside the ETIS. A series of experiments with different fire scenarios were done: no fire barrier, two fire barriers and three fire barriers at different heights. Test results were compared. The results show that the ETIS using EPS without fire barriers almost burned out, while the ETIS with fire barriers performed well in preventing fire spread. The temperatures above the fire barrier were much lower than those below the fire barrier, and most of the insulation materials above the top fire barrier stayed in place.

Synchronous spikes are necessary but not sufficient for a synchrony code in populations of spiking neurons.

Science.gov (United States)

Grewe, Jan; Kruscha, Alexandra; Lindner, Benjamin; Benda, Jan

2017-03-07

Synchronous activity in populations of neurons potentially encodes special stimulus features. Selective readout of either synchronous or asynchronous activity allows formation of two streams of information processing. Theoretical work predicts that such a synchrony code is a fundamental feature of populations of spiking neurons if they operate in specific noise and stimulus regimes. Here we experimentally test the theoretical predictions by quantifying and comparing neuronal response properties in tuberous and ampullary electroreceptor afferents of the weakly electric fish Apteronotus leptorhynchus These related systems show similar levels of synchronous activity, but only in the more irregularly firing tuberous afferents a synchrony code is established, whereas in the more regularly firing ampullary afferents it is not. The mere existence of synchronous activity is thus not sufficient for a synchrony code. Single-cell features such as the irregularity of spiking and the frequency dependence of the neuron's transfer function determine whether synchronous spikes possess a distinct meaning for the encoding of time-dependent signals.

Behavior of the aerosols generated by sodium sheet fires

International Nuclear Information System (INIS)

Fermandjian, J.; Boulaud, D.; Madelaine, G.; Malet, J.C.; Casselman, C.; Duverger de Cuy, G.

1980-04-01

In order to validate computing models an experimental programme of sodium sheet fire tests (weight of sodium = 10 kg - combustion area = 0.125 m 2 - initial sodium temperature = 450 0 C) is under way in a 4x4 m 3 steel chamber (diameter = 1.6 m - height = 2.2 m - wall surface/volume = 3.4 m -1 - floor surface/volume = 0.46 m -1 ) with weight concentrations of aerosol above 10 g Na 2 O 2 /m 3 . The following experimental data were obtained: changes in the weight concentration and in the mass distribution of particles in suspension, especially by the use of cascade impactors (Andersen 8 stages) with a dilution system; particle emission rate with time (fire divided into a number of sequences on the basis of the reference test and fire timed by placing a lid on the container); kinetics of the aerosol deposition on the chamber floor (0.24 g Na 2 O 2 /m 2 .s). The application of computing codes (HAARM 3 and PARDISEKO 3B) to these tests showed agreement between experiments and calculations [fr

Identification of important phenomena under sodium fire accidents based on PIRT process with factor analysis in sodium-cooled fast reactor

International Nuclear Information System (INIS)

Aoyagi, Mitsuhiro; Uchibori, Akihiro; Kikuchi, Shin; Takata, Takashi; Ohno, Shuji; Ohshima, Hiroyuki

2016-01-01

The PIRT (Phenomena Identification and Ranking Table) process is an effective method to identify key phenomena involved in safety issues in nuclear power plants. The present PIRT process is aimed to validate sodium fire analysis codes. Because a sodium fire accident in sodium-cooled fast reactor (SFR) involves complex phenomena, various figures of merit (FOMs) could exist in this PIRT process. In addition, importance evaluation of phenomena for each FOM should be implemented in an objective manner under the PIRT process. This paper describes the methodology for specification of FOMs, identification of associated phenomena and importance evaluation of each associated phenomenon in order to complete a ranking table of important phenomena involved in a sodium fire accident in an SFR. The FOMs were specified through factor analysis in this PIRT process. Physical parameters to be quantified by a sodium fire analysis code were identified by considering concerns resulting from sodium fire in the factor analysis. Associated phenomena were identified through the element- and sequence-based phenomena analyses as is often conducted in PIRT processes. Importance of each associated phenomenon was evaluated by considering the sequence-based analysis of associated phenomena correlated with the FOMs. Then, we complete the ranking table through the factor and phenomenon analyses. (author)

Optimizing prescribed fire allocation for managing fire risk in central Catalonia.

Science.gov (United States)

Alcasena, Fermín J; Ager, Alan A; Salis, Michele; Day, Michelle A; Vega-Garcia, Cristina

2018-04-15

We used spatial optimization to allocate and prioritize prescribed fire treatments in the fire-prone Bages County, central Catalonia (northeastern Spain). The goal of this study was to identify suitable strategic locations on forest lands for fuel treatments in order to: 1) disrupt major fire movements, 2) reduce ember emissions, and 3) reduce the likelihood of large fires burning into residential communities. We first modeled fire spread, hazard and exposure metrics under historical extreme fire weather conditions, including node influence grid for surface fire pathways, crown fraction burned and fire transmission to residential structures. Then, we performed an optimization analysis on individual planning areas to identify production possibility frontiers for addressing fire exposure and explore alternative prescribed fire treatment configurations. The results revealed strong trade-offs among different fire exposure metrics, showed treatment mosaics that optimize the allocation of prescribed fire, and identified specific opportunities to achieve multiple objectives. Our methods can contribute to improving the efficiency of prescribed fire treatment investments and wildfire management programs aimed at creating fire resilient ecosystems, facilitating safe and efficient fire suppression, and safeguarding rural communities from catastrophic wildfires. The analysis framework can be used to optimally allocate prescribed fire in other fire-prone areas within the Mediterranean region and elsewhere. Copyright © 2017 Elsevier B.V. All rights reserved.

Spike-based population coding and working memory.

Directory of Open Access Journals (Sweden)

Martin Boerlin

2011-02-01

Full Text Available Compelling behavioral evidence suggests that humans can make optimal decisions despite the uncertainty inherent in perceptual or motor tasks. A key question in neuroscience is how populations of spiking neurons can implement such probabilistic computations. In this article, we develop a comprehensive framework for optimal, spike-based sensory integration and working memory in a dynamic environment. We propose that probability distributions are inferred spike-per-spike in recurrently connected networks of integrate-and-fire neurons. As a result, these networks can combine sensory cues optimally, track the state of a time-varying stimulus and memorize accumulated evidence over periods much longer than the time constant of single neurons. Importantly, we propose that population responses and persistent working memory states represent entire probability distributions and not only single stimulus values. These memories are reflected by sustained, asynchronous patterns of activity which make relevant information available to downstream neurons within their short time window of integration. Model neurons act as predictive encoders, only firing spikes which account for new information that has not yet been signaled. Thus, spike times signal deterministically a prediction error, contrary to rate codes in which spike times are considered to be random samples of an underlying firing rate. As a consequence of this coding scheme, a multitude of spike patterns can reliably encode the same information. This results in weakly correlated, Poisson-like spike trains that are sensitive to initial conditions but robust to even high levels of external neural noise. This spike train variability reproduces the one observed in cortical sensory spike trains, but cannot be equated to noise. On the contrary, it is a consequence of optimal spike-based inference. In contrast, we show that rate-based models perform poorly when implemented with stochastically spiking neurons.

Enhanced Fire Events Database to Support Fire PRA

International Nuclear Information System (INIS)

Baranowsky, Patrick; Canavan, Ken; St. Germain, Shawn

2010-01-01

This paper provides a description of the updated and enhanced Fire Events Data Base (FEDB) developed by the Electric Power Research Institute (EPRI) in cooperation with the U.S. Nuclear Regulatory Commission (NRC). The FEDB is the principal source of fire incident operational data for use in fire PRAs. It provides a comprehensive and consolidated source of fire incident information for nuclear power plants operating in the U.S. The database classification scheme identifies important attributes of fire incidents to characterize their nature, causal factors, and severity consistent with available data. The database provides sufficient detail to delineate important plant specific attributes of the incidents to the extent practical. A significant enhancement to the updated FEDB is the reorganization and refinement of the database structure and data fields and fire characterization details added to more rigorously capture the nature and magnitude of the fire and damage to the ignition source and nearby equipment and structures.

Fire Behavior (FB)

Science.gov (United States)

Robert E. Keane

2006-01-01

The Fire Behavior (FB) method is used to describe the behavior of the fire and the ambient weather and fuel conditions that influence the fire behavior. Fire behavior methods are not plot based and are collected by fire event and time-date. In general, the fire behavior data are used to interpret the fire effects documented in the plot-level sampling. Unlike the other...

A Survey of a System of Methods for Fire Safety Design of Traditional Concrete Constructions

DEFF Research Database (Denmark)

Hertz, Kristian

2000-01-01

constructions DS411. And the bases for many of the methods have been distributed by CIB W14 reports. But a survey of all the methods in coherence has never been presented, and much of this documentation and the additional documentation produced for the work with the codes needs still to be printed in papers......During the years since 1978 the author has been developing a series of calculation methods and sup-porting test methods for the fire safety design of concrete constructions. The basic methods have been adopted in the fire chapters of the Eurocode ENV1992-1-2 and the Danish code for concrete.......It is the aim of this paper to give a coherent presentation of the design methods, their degree of documentation and the available references in order to facilitate the application of them....

Planning for risk-informed/performance-based fire protection at nuclear power plants. Final report

International Nuclear Information System (INIS)

Najafi, B.; Parkinson, W.J.; Lee, J.A.

1997-12-01

This document presents a framework for discussing issues and building consensus towards use of fire modeling and risk technology in nuclear power plant fire protection program implementation. The plan describes a three-phase approach: development of core technologies, implementation of methods, and finally, case studies and pilot applications to verify viability of such methods. The core technologies are defined as fire modeling, fire and system tests, use of operational data, and system and risk techniques. The implementation phase addresses the programmatic issues involved in implementing a risk-informed/performance-based approach in an integrated approach with risk/performance measures. The programmatic elements include: (1) a relationship with fire codes and standards development as defined by the ongoing effort of NFPA for development of performance-based standards; (2) the ability for NRC to undertake inspection and enforcement; and (3) the benefit to utilities in terms of cost versus safety. The case studies are intended to demonstrate applicability of single issue resolution while pilot applications are intended to check the applicability of the integrated program as a whole

The influence of fire retardants on the properties of beech and poplar veneers and plywood

Directory of Open Access Journals (Sweden)

Miljković Jovan

2005-01-01

Full Text Available Rising demands for fire resistance properties of wood construction and elements matching new standards have been an important part of building codes during the last decade. On the other side, lack of more detailed research on interaction between wood species and selected fire retardant chemicals even with basically one is evident. This is particularly truth with domestic wood species. In this research, beech and poplar veneers were immersed in 25% solutions of monoammonium phosphate (MP and sodium acetate (SA and impregnated for different periods of time. To determine the preliminary level of fire retardancy achieved in veneers before manufacturing of finished plywood, thermo gravimetric (TG and derivative thermo gravimetric (DTG methods were used. TG and DTG analyses of treated and untreated wood, as well as of fire retardants alone, were performed. The next properties of impregnated and no impregnated veneers and plywood were determined: absorption of imp regnant solution (A, weight percent gain (WPG of imp regnant, equilibrium moisture content (EMC, pH values, and in the case of plywood, strength and fire resistance. Fire resistance of plywood was tested in accordance with standard test for resistance to the effects of fire and the most efficient fire retardant, monoammonium phosphate, had the same result as TG/DTG analyses, which pointed out the validity of TG methods in predicting fire resistance of future products.

Detection and Characterization of Low Temperature Peat Fires during the 2015 Fire Catastrophe in Indonesia Using a New High-Sensitivity Fire Monitoring Satellite Sensor (FireBird).

Science.gov (United States)

Atwood, Elizabeth C; Englhart, Sandra; Lorenz, Eckehard; Halle, Winfried; Wiedemann, Werner; Siegert, Florian

2016-01-01

Vast and disastrous fires occurred on Borneo during the 2015 dry season, pushing Indonesia into the top five carbon emitting countries. The region was affected by a very strong El Niño-Southern Oscillation (ENSO) climate phenomenon, on par with the last severe event in 1997/98. Fire dynamics in Central Kalimantan were investigated using an innovative sensor offering higher sensitivity to a wider range of fire intensities at a finer spatial resolution (160 m) than heretofore available. The sensor is onboard the TET-1 satellite, part of the German Aerospace Center (DLR) FireBird mission. TET-1 images (acquired every 2-3 days) from the middle infrared were used to detect fires continuously burning for almost three weeks in the protected peatlands of Sebangau National Park as well as surrounding areas with active logging and oil palm concessions. TET-1 detection capabilities were compared with MODIS active fire detection and Landsat burned area algorithms. Fire dynamics, including fire front propagation speed and area burned, were investigated. We show that TET-1 has improved detection capabilities over MODIS in monitoring low-intensity peatland fire fronts through thick smoke and haze. Analysis of fire dynamics revealed that the largest burned areas resulted from fire front lines started from multiple locations, and the highest propagation speeds were in excess of 500 m/day (all over peat > 2m deep). Fires were found to occur most often in concessions that contained drainage infrastructure but were not cleared prior to the fire season. Benefits of implementing this sensor system to improve current fire management techniques are discussed. Near real-time fire detection together with enhanced fire behavior monitoring capabilities would not only improve firefighting efforts, but also benefit analysis of fire impact on tropical peatlands, greenhouse gas emission estimations as well as mitigation measures to reduce severe fire events in the future.

Fire-driven alien invasion in a fire-adapted ecosystem

Science.gov (United States)

Keeley, Jon E.; Brennan, Teresa J.

2012-01-01

Disturbance plays a key role in many alien plant invasions. However, often the main driver of invasion is not disturbance per se but alterations in the disturbance regime. In some fire-adapted shrublands, the community is highly resilient to infrequent, high-intensity fires, but changes in the fire regime that result in shorter fire intervals may make these communities more susceptible to alien plant invasions. This study examines several wildfire events that resulted in short fire intervals in California chaparral shrublands. In one study, we compared postfire recovery patterns in sites with different prefire stand ages (3 and 24 years), and in another study we compared sites that had burned once in four years with sites that had burned twice in this period. The population size of the dominant native shrub Adenostoma fasciculatum was drastically reduced following fire in the 3-year sites relative to the 24-year sites. The 3-year sites had much greater alien plant cover and significantly lower plant diversity than the 24-year sites. In a separate study, repeat fires four years apart on the same sites showed that annual species increased significantly after the second fire, and alien annuals far outnumbered native annuals. Aliens included both annual grasses and annual forbs and were negatively correlated with woody plant cover. Native woody species regenerated well after the first fire but declined after the second fire, and one obligate seeding shrub was extirpated from two sites by the repeat fires. It is concluded that some fire-adapted shrublands are vulnerable to changes in fire regime, and this can lead to a loss of native diversity and put the community on a trajectory towards type conversion from a woody to an herbaceous system. Such changes result in alterations in the proportion of natives to non-natives, changes in functional types from deeply rooted shrubs to shallow rooted grasses and forbs, increased fire frequency due to the increase in fine fuels

Fire-driven alien invasion in a fire-adapted ecosystem.

Science.gov (United States)

Keeley, Jon E; Brennan, Teresa J

2012-08-01

Disturbance plays a key role in many alien plant invasions. However, often the main driver of invasion is not disturbance per se but alterations in the disturbance regime. In some fire-adapted shrublands, the community is highly resilient to infrequent, high-intensity fires, but changes in the fire regime that result in shorter fire intervals may make these communities more susceptible to alien plant invasions. This study examines several wildfire events that resulted in short fire intervals in California chaparral shrublands. In one study, we compared postfire recovery patterns in sites with different prefire stand ages (3 and 24 years), and in another study we compared sites that had burned once in four years with sites that had burned twice in this period. The population size of the dominant native shrub Adenostoma fasciculatum was drastically reduced following fire in the 3-year sites relative to the 24-year sites. The 3-year sites had much greater alien plant cover and significantly lower plant diversity than the 24-year sites. In a separate study, repeat fires four years apart on the same sites showed that annual species increased significantly after the second fire, and alien annuals far outnumbered native annuals. Aliens included both annual grasses and annual forbs and were negatively correlated with woody plant cover. Native woody species regenerated well after the first fire but declined after the second fire, and one obligate seeding shrub was extirpated from two sites by the repeat fires. It is concluded that some fire-adapted shrublands are vulnerable to changes in fire regime, and this can lead to a loss of native diversity and put the community on a trajectory towards type conversion from a woody to an herbaceous system. Such changes result in alterations in the proportion of natives to non-natives, changes in functional types from deeply rooted shrubs to shallow rooted grasses and forbs, increased fire frequency due to the increase in fine fuels

A Novel Arc Fault Detector for Early Detection of Electrical Fires.

Science.gov (United States)

Yang, Kai; Zhang, Rencheng; Yang, Jianhong; Liu, Canhua; Chen, Shouhong; Zhang, Fujiang

2016-04-09

Arc faults can produce very high temperatures and can easily ignite combustible materials; thus, they represent one of the most important causes of electrical fires. The application of arc fault detection, as an emerging early fire detection technology, is required by the National Electrical Code to reduce the occurrence of electrical fires. However, the concealment, randomness and diversity of arc faults make them difficult to detect. To improve the accuracy of arc fault detection, a novel arc fault detector (AFD) is developed in this study. First, an experimental arc fault platform is built to study electrical fires. A high-frequency transducer and a current transducer are used to measure typical load signals of arc faults and normal states. After the common features of these signals are studied, high-frequency energy and current variations are extracted as an input eigenvector for use by an arc fault detection algorithm. Then, the detection algorithm based on a weighted least squares support vector machine is designed and successfully applied in a microprocessor. Finally, an AFD is developed. The test results show that the AFD can detect arc faults in a timely manner and interrupt the circuit power supply before electrical fires can occur. The AFD is not influenced by cross talk or transient processes, and the detection accuracy is very high. Hence, the AFD can be installed in low-voltage circuits to monitor circuit states in real-time to facilitate the early detection of electrical fires.

A Novel Arc Fault Detector for Early Detection of Electrical Fires

Science.gov (United States)

Yang, Kai; Zhang, Rencheng; Yang, Jianhong; Liu, Canhua; Chen, Shouhong; Zhang, Fujiang

2016-01-01

Arc faults can produce very high temperatures and can easily ignite combustible materials; thus, they represent one of the most important causes of electrical fires. The application of arc fault detection, as an emerging early fire detection technology, is required by the National Electrical Code to reduce the occurrence of electrical fires. However, the concealment, randomness and diversity of arc faults make them difficult to detect. To improve the accuracy of arc fault detection, a novel arc fault detector (AFD) is developed in this study. First, an experimental arc fault platform is built to study electrical fires. A high-frequency transducer and a current transducer are used to measure typical load signals of arc faults and normal states. After the common features of these signals are studied, high-frequency energy and current variations are extracted as an input eigenvector for use by an arc fault detection algorithm. Then, the detection algorithm based on a weighted least squares support vector machine is designed and successfully applied in a microprocessor. Finally, an AFD is developed. The test results show that the AFD can detect arc faults in a timely manner and interrupt the circuit power supply before electrical fires can occur. The AFD is not influenced by cross talk or transient processes, and the detection accuracy is very high. Hence, the AFD can be installed in low-voltage circuits to monitor circuit states in real-time to facilitate the early detection of electrical fires. PMID:27070618

Methodology for sodium fire vulnerability assessment of sodium cooled fast reactor based on the Monte-Carlo principle

Energy Technology Data Exchange (ETDEWEB)

Song, Wei [Nuclear and Radiation Safety Center, P. O. Box 8088, Beijing (China); Wu, Yuanyu [ITER Organization, Route de Vinon-sur-Verdon, 13115 Saint-Paul-lès-Durance (France); Hu, Wenjun [China Institute of Atomic Energy, P. O. Box 275(34), Beijing (China); Zuo, Jiaxu, E-mail: zuojiaxu@chinansc.cn [Nuclear and Radiation Safety Center, P. O. Box 8088, Beijing (China)

2015-11-15

Highlights: • Monte-Carlo principle coupling with fire dynamic code is adopted to perform sodium fire vulnerability assessment. • The method can be used to calculate the failure probability of sodium fire scenarios. • A calculation example and results are given to illustrate the feasibility of the methodology. • Some critical parameters and experience are shared. - Abstract: Sodium fire is a typical and distinctive hazard in sodium cooled fast reactors, which is significant for nuclear safety. In this paper, a method of sodium fire vulnerability assessment based on the Monte-Carlo principle was introduced, which could be used to calculate the probabilities of every failure mode in sodium fire scenarios. After that, the sodium fire scenario vulnerability assessment of primary cold trap room of China Experimental Fast Reactor was performed to illustrate the feasibility of the methodology. The calculation result of the example shows that the conditional failure probability of key cable is 23.6% in the sodium fire scenario which is caused by continuous sodium leakage because of the isolation device failure, but the wall temperature, the room pressure and the aerosol discharge mass are all lower than the safety limits.

Methodology for sodium fire vulnerability assessment of sodium cooled fast reactor based on the Monte-Carlo principle

International Nuclear Information System (INIS)

Song, Wei; Wu, Yuanyu; Hu, Wenjun; Zuo, Jiaxu

2015-01-01

Highlights: • Monte-Carlo principle coupling with fire dynamic code is adopted to perform sodium fire vulnerability assessment. • The method can be used to calculate the failure probability of sodium fire scenarios. • A calculation example and results are given to illustrate the feasibility of the methodology. • Some critical parameters and experience are shared. - Abstract: Sodium fire is a typical and distinctive hazard in sodium cooled fast reactors, which is significant for nuclear safety. In this paper, a method of sodium fire vulnerability assessment based on the Monte-Carlo principle was introduced, which could be used to calculate the probabilities of every failure mode in sodium fire scenarios. After that, the sodium fire scenario vulnerability assessment of primary cold trap room of China Experimental Fast Reactor was performed to illustrate the feasibility of the methodology. The calculation result of the example shows that the conditional failure probability of key cable is 23.6% in the sodium fire scenario which is caused by continuous sodium leakage because of the isolation device failure, but the wall temperature, the room pressure and the aerosol discharge mass are all lower than the safety limits.

Comparative evaluation of the INNO-LIA syphilis score and the MarDx Treponema pallidum immunoglobulin G Marblot test assays for the serological diagnosis of syphilis.

Science.gov (United States)

Lam, T K; Lau, H Y; Lee, Y P; Fung, S M; Leung, W L; Kam, K M

2010-02-01

We evaluated the performance of two immunoblot assays: the INNO-LIA Syphilis Score (LIA) and the MarDx T. pallidum IgG Marblot Test (TWB), as compared with that of the Murex ICE Syphilis enzyme immunoassay (EIA), the Serodia Treponema pallidum particle agglutination (TPPA) assay and the fluorescent treponemal antibody-absorption (FTA-abs) assay, for the serological diagnosis of syphilis using serum samples of 135 attendees of the social hygiene clinics of the Department of Health in Hong Kong newly diagnosed with syphilis and provided with clinical stages (39 in primary, 20 in secondary, 18 in early latent and 58 in latent of unknown duration) and of 43 normal healthy subjects between October and December 2004. The differences in the overall sensitivities of the LIA assay and the EIA/TPPA/FTA-abs assays were not statistically significant (P > 0.05) whereas the overall sensitivity of the TWB assay was significantly lower (P FTA-abs assays. The LIA assay had an overall sensitivity of 94.1% (95% CI 88.7-97.0%) whereas the TWB assay 65.2% (95% CI 56.8-72.7%). Both the LIA and the TWB assays have a specificity of 100%. When consensus results were derived from the most predominant results of the EIA, the TPPA and the FTA-abs assays, the LIA assay had a positive agreement with the consensus results of 98.5% (95% CI 94.5-99.6%) whereas the TWB assay 68.2% (95% CI 59.8-75.6%). Therefore, the LIA assay performed significantly better (P < 0.05) than the TWB assay. The LIA assay can be considered to be a valid alternative confirmatory test for the serological diagnosis of syphilis.

Post-fire vegetation and fuel development influences fire severity patterns in reburns.

Science.gov (United States)

Coppoletta, Michelle; Merriam, Kyle E; Collins, Brandon M

2016-04-01

In areas where fire regimes and forest structure have been dramatically altered, there is increasing concern that contemporary fires have the potential to set forests on a positive feedback trajectory with successive reburns, one in which extensive stand-replacing fire could promote more stand-replacing fire. Our study utilized an extensive set of field plots established following four fires that occurred between 2000 and 2010 in the northern Sierra Nevada, California, USA that were subsequently reburned in 2012. The information obtained from these field plots allowed for a unique set of analyses investigating the effect of vegetation, fuels, topography, fire weather, and forest management on reburn severity. We also examined the influence of initial fire severity and time since initial fire on influential predictors of reburn severity. Our results suggest that high- to moderate-severity fire in the initial fires led to an increase in standing snags and shrub vegetation, which in combination with severe fire weather promoted high-severity fire effects in the subsequent reburn. Although fire behavior is largely driven by weather, our study demonstrates that post-fire vegetation composition and structure are also important drivers of reburn severity. In the face of changing climatic regimes and increases in extreme fire weather, these results may provide managers with options to create more fire-resilient ecosystems. In areas where frequent high-severity fire is undesirable, management activities such as thinning, prescribed fire, or managed wildland fire can be used to moderate fire behavior not only prior to initial fires, but also before subsequent reburns.

Fire intensity impacts on post-fire temperate coniferous forest net primary productivity

Science.gov (United States)

Sparks, Aaron M.; Kolden, Crystal A.; Smith, Alistair M. S.; Boschetti, Luigi; Johnson, Daniel M.; Cochrane, Mark A.

2018-02-01

Fire is a dynamic ecological process in forests and impacts the carbon (C) cycle through direct combustion emissions, tree mortality, and by impairing the ability of surviving trees to sequester carbon. While studies on young trees have demonstrated that fire intensity is a determinant of post-fire net primary productivity, wildland fires on landscape to regional scales have largely been assumed to either cause tree mortality, or conversely, cause no physiological impact, ignoring the impacted but surviving trees. Our objective was to understand how fire intensity affects post-fire net primary productivity in conifer-dominated forested ecosystems on the spatial scale of large wildland fires. We examined the relationships between fire radiative power (FRP), its temporal integral (fire radiative energy - FRE), and net primary productivity (NPP) using 16 years of data from the MOderate Resolution Imaging Spectrometer (MODIS) for 15 large fires in western United States coniferous forests. The greatest NPP post-fire loss occurred 1 year post-fire and ranged from -67 to -312 g C m-2 yr-1 (-13 to -54 %) across all fires. Forests dominated by fire-resistant species (species that typically survive low-intensity fires) experienced the lowest relative NPP reductions compared to forests with less resistant species. Post-fire NPP in forests that were dominated by fire-susceptible species were not as sensitive to FRP or FRE, indicating that NPP in these forests may be reduced to similar levels regardless of fire intensity. Conversely, post-fire NPP in forests dominated by fire-resistant and mixed species decreased with increasing FRP or FRE. In some cases, this dose-response relationship persisted for more than a decade post-fire, highlighting a legacy effect of fire intensity on post-fire C dynamics in these forests.

A Method of Fire Scenarios Identification in a Consolidated Fire Risk Analysis

International Nuclear Information System (INIS)

Lim, Ho Gon; Han, Sang Hoon; Yang, Joon Eon

2010-01-01

Conventional fire PSA consider only two cases of fire scenarios, that is one for fire without propagation and the other for single propagation to neighboring compartment. Recently, a consolidated fire risk analysis using single fault tree (FT) was developed. However, the fire scenario identification in the new method is similar to conventional fire analysis method. The present study develops a new method of fire scenario identification in a consolidated fire risk analysis method. An equation for fire propagation is developed to identify fire scenario and a mapping method of fire scenarios into internal event risk model is discussed. Finally, an algorithm for automatic program is suggested

Fire and fire ecology: Concepts and principles

Science.gov (United States)

Mark A. Cochrane; Kevin C. Ryan

2009-01-01

Fire has been central to terrestrial life ever since early anaerobic microorganisms poisoned the atmosphere with oxygen and multicellular plant life moved onto land. The combination of fuels, oxygen, and heat gave birth to fire on Earth. Fire is not just another evolutionary challenge that life needed to overcome, it is, in fact, a core ecological process across much...

Forest fires

International Nuclear Information System (INIS)

Fuller, M.

1991-01-01

This book examines the many complex and sensitive issues relating to wildland fires. Beginning with an overview of the fires of 1980s, the book discusses the implications of continued drought and considers the behavior of wildland fires, from ignition and spread to spotting and firestorms. Topics include the effects of weather, forest fuels, fire ecology, and the effects of fire on plants and animals. In addition, the book examines firefighting methods and equipment, including new minimum impact techniques and compressed air foam; prescribed burning; and steps that can be taken to protect individuals and human structures. A history of forest fire policies in the U.S. and a discussion of solutions to fire problems around the world completes the coverage. With one percent of the earth's surface burning every year in the last decade, this is a penetrating book on a subject of undeniable importance

Detection and Characterization of Low Temperature Peat Fires during the 2015 Fire Catastrophe in Indonesia Using a New High-Sensitivity Fire Monitoring Satellite Sensor (FireBird)

Science.gov (United States)

Atwood, Elizabeth C.; Englhart, Sandra; Lorenz, Eckehard; Halle, Winfried; Wiedemann, Werner; Siegert, Florian

2016-01-01

Vast and disastrous fires occurred on Borneo during the 2015 dry season, pushing Indonesia into the top five carbon emitting countries. The region was affected by a very strong El Niño-Southern Oscillation (ENSO) climate phenomenon, on par with the last severe event in 1997/98. Fire dynamics in Central Kalimantan were investigated using an innovative sensor offering higher sensitivity to a wider range of fire intensities at a finer spatial resolution (160 m) than heretofore available. The sensor is onboard the TET-1 satellite, part of the German Aerospace Center (DLR) FireBird mission. TET-1 images (acquired every 2–3 days) from the middle infrared were used to detect fires continuously burning for almost three weeks in the protected peatlands of Sebangau National Park as well as surrounding areas with active logging and oil palm concessions. TET-1 detection capabilities were compared with MODIS active fire detection and Landsat burned area algorithms. Fire dynamics, including fire front propagation speed and area burned, were investigated. We show that TET-1 has improved detection capabilities over MODIS in monitoring low-intensity peatland fire fronts through thick smoke and haze. Analysis of fire dynamics revealed that the largest burned areas resulted from fire front lines started from multiple locations, and the highest propagation speeds were in excess of 500 m/day (all over peat > 2m deep). Fires were found to occur most often in concessions that contained drainage infrastructure but were not cleared prior to the fire season. Benefits of implementing this sensor system to improve current fire management techniques are discussed. Near real-time fire detection together with enhanced fire behavior monitoring capabilities would not only improve firefighting efforts, but also benefit analysis of fire impact on tropical peatlands, greenhouse gas emission estimations as well as mitigation measures to reduce severe fire events in the future. PMID:27486664

Radiation Coupling with the FUN3D Unstructured-Grid CFD Code

Science.gov (United States)

Wood, William A.

2012-01-01

The HARA radiation code is fully-coupled to the FUN3D unstructured-grid CFD code for the purpose of simulating high-energy hypersonic flows. The radiation energy source terms and surface heat transfer, under the tangent slab approximation, are included within the fluid dynamic ow solver. The Fire II flight test, at the Mach-31 1643-second trajectory point, is used as a demonstration case. Comparisons are made with an existing structured-grid capability, the LAURA/HARA coupling. The radiative surface heat transfer rates from the present approach match the benchmark values within 6%. Although radiation coupling is the focus of the present work, convective surface heat transfer rates are also reported, and are seen to vary depending upon the choice of mesh connectivity and FUN3D ux reconstruction algorithm. On a tetrahedral-element mesh the convective heating matches the benchmark at the stagnation point, but under-predicts by 15% on the Fire II shoulder. Conversely, on a mixed-element mesh the convective heating over-predicts at the stagnation point by 20%, but matches the benchmark away from the stagnation region.

Browns Ferry fire

International Nuclear Information System (INIS)

Harkleroad, J.R.

1983-01-01

A synopsis of the March 22, 1975 fire at Browns Ferry Nuclear Plant is discussed. Emphasis is placed on events prior to and during the fire. How the fire started, fire fighting activities, fire and smoke development, and restoration activities are discussed

Overview of the 2013 FireFlux II grass fire field experiment

Science.gov (United States)

C.B. Clements; B. Davis; D. Seto; J. Contezac; A. Kochanski; J.-B. Fillipi; N. Lareau; B. Barboni; B. Butler; S. Krueger; R. Ottmar; R. Vihnanek; W.E. Heilman; J. Flynn; M.A. Jenkins; J. Mandel; C. Teske; D. Jimenez; J. O' Brien; B. Lefer

2014-01-01

In order to better understand the dynamics of fire-atmosphere interactions and the role of micrometeorology on fire behaviour the FireFlux campaign was conducted in 2006 on a coastal tall-grass prairie in southeast Texas, USA. The FireFlux campaign dataset has become the international standard for evaluating coupled fire-atmosphere model systems. While FireFlux is one...

Numerical simulations of forest fire propagation and smoke transport as an external hazard assessment methodology development for a nuclear power plant

International Nuclear Information System (INIS)

Okano, Yasushi; Yamano, Hidemasa

2016-01-01

A new method has been developed to assess potential challenges by forest fire smoke on a cooling function of a decay heat removal system (DHRS) of a sodium-cooled fast reactor. Combinational numerical simulations of a forest fire propagation and a smoke transport were performed to evaluate a cumulative amount of smoke captured on air filters of the DHRS. The forest fire propagation simulations were performed using FARSITE code to evaluate a temporal increase of a forest fire spread area, a frontal fireline location, reaction intensity, and fireline intensity. Peripheral boundary of the forest fire spread area is shaped like an ellipse on the terrain, and the active forest fire area from which smoke is produced as a forest fire product is increased with forest fire spread. The smoke transport simulations were performed using ALOFT-FT code where a spatial distribution of smoke density, especially of particle matter (PM), is evaluated. The snapshot (i.e. at a certain time step) outputs by FARSITE on the reaction intensity and the fireline intensity were utilized as the input data for ALOFT-FT, while it was conservatively assumed that the smoke generated from the active forest fire area along the periphery boundary rises up from the frontal fireline location nearest to a nuclear power plant (NPP) and that prevailing wind transports all smoke to an NPP in the leeward side. The evaluated time-dependent changes of spatial PM density were utilized to calculate a cumulative amount of PM captured on the air filters of the DHRS. Sensitivity analysis was performed on prevailing wind speed to which both the fireline intensity and the smoke transport behavior are sensitive. The total amount of PM on the air filters was conservatively estimated around several hundred grams per m 2 which is well below the utilization limit. (author)

Fire models for assessment of nuclear power plant fires

International Nuclear Information System (INIS)

Nicolette, V.F.; Nowlen, S.P.

1989-01-01

This paper reviews the state-of-the-art in available fire models for the assessment of nuclear power plants fires. The advantages and disadvantages of three basic types of fire models (zone, field, and control volume) and Sandia's experience with these models will be discussed. It is shown that the type of fire model selected to solve a particular problem should be based on the information that is required. Areas of concern which relate to all nuclear power plant fire models are identified. 17 refs., 6 figs

Fire severity and ecosytem responses following crown fires in California shrublands.

Science.gov (United States)

Keeley, Jon E; Brennan, Teresa; Pfaff, Anne H

2008-09-01

Chaparral shrublands burn in large high-intensity crown fires. Managers interested in how these wildfires affect ecosystem processes generally rely on surrogate measures of fire intensity known as fire severity metrics. In shrublands burned in the autumn of 2003, a study of 250 sites investigated factors determining fire severity and ecosystem responses. Using structural equation modeling we show that stand age, prefire shrub density, and the shortest interval of the prior fire history had significant direct effects on fire severity, explaining > 50% of the variation in severity. Fire severity per se is of interest to resource managers primarily because it is presumed to be an indicator of important ecosystem processes such as vegetative regeneration, community recovery, and erosion. Fire severity contributed relatively little to explaining patterns of regeneration after fire. Two generalizations can be drawn: fire severity effects are mostly shortlived, i.e., by the second year they are greatly diminished, and fire severity may have opposite effects on different functional types. Species richness exhibited a negative relationship to fire severity in the first year, but fire severity impacts were substantially less in the second postfire year and varied by functional type. Much of this relationship was due to alien plants that are sensitive to high fire severity; at all scales from 1 to 1000 m2, the percentage of alien species in the postfire flora declined with increased fire severity. Other aspects of disturbance history are also important determinants of alien cover and richness as both increased with the number of times the site had burned and decreased with time since last fire. A substantial number of studies have shown that remote-sensing indices are correlated with field measurements of fire severity. Across our sites, absolute differenced normalized burn ratio (dNBR) was strongly correlated with field measures of fire severity and with fire history at a

Sensory Coding by Cerebellar Mossy Fibres through Inhibition-Driven Phase Resetting and Synchronisation

Science.gov (United States)

Holtzman, Tahl; Jörntell, Henrik

2011-01-01

Temporal coding of spike-times using oscillatory mechanisms allied to spike-time dependent plasticity could represent a powerful mechanism for neuronal communication. However, it is unclear how temporal coding is constructed at the single neuronal level. Here we investigate a novel class of highly regular, metronome-like neurones in the rat brainstem which form a major source of cerebellar afferents. Stimulation of sensory inputs evoked brief periods of inhibition that interrupted the regular firing of these cells leading to phase-shifted spike-time advancements and delays. Alongside phase-shifting, metronome cells also behaved as band-pass filters during rhythmic sensory stimulation, with maximal spike-stimulus synchronisation at frequencies close to the idiosyncratic firing frequency of each neurone. Phase-shifting and band-pass filtering serve to temporally align ensembles of metronome cells, leading to sustained volleys of near-coincident spike-times, thereby transmitting synchronised sensory information to downstream targets in the cerebellar cortex. PMID:22046297

Sensory coding by cerebellar mossy fibres through inhibition-driven phase resetting and synchronisation.

Directory of Open Access Journals (Sweden)

Tahl Holtzman

Full Text Available Temporal coding of spike-times using oscillatory mechanisms allied to spike-time dependent plasticity could represent a powerful mechanism for neuronal communication. However, it is unclear how temporal coding is constructed at the single neuronal level. Here we investigate a novel class of highly regular, metronome-like neurones in the rat brainstem which form a major source of cerebellar afferents. Stimulation of sensory inputs evoked brief periods of inhibition that interrupted the regular firing of these cells leading to phase-shifted spike-time advancements and delays. Alongside phase-shifting, metronome cells also behaved as band-pass filters during rhythmic sensory stimulation, with maximal spike-stimulus synchronisation at frequencies close to the idiosyncratic firing frequency of each neurone. Phase-shifting and band-pass filtering serve to temporally align ensembles of metronome cells, leading to sustained volleys of near-coincident spike-times, thereby transmitting synchronised sensory information to downstream targets in the cerebellar cortex.

Phasic firing in vasopressin cells: understanding its functional significance through computational models.

Directory of Open Access Journals (Sweden)

Duncan J MacGregor

. These findings show large differences in information coding between the populations, and apparent functional advantages of asynchronous phasic firing.

Prevalencia de anticuerpos antitreponémicos y características sociodemográficas de la población mexicana adulta en el año 2000 Anti-Treponema pallidum seroprevalence and sociodemographic characteristics in Mexican adult population, 2000

Directory of Open Access Journals (Sweden)

Carlos J Conde-González

2007-01-01

Full Text Available OBJETIVO: Determinar la frecuencia de anticuerpos antitreponémicos en mexicanos adultos de ambos sexos y las características de la población relacionadas con la infección sifilítica. MATERIAL Y MÉTODOS: Se analizaron para anti-Treponema pallidum 12 010 sueros seleccionados de forma aleatoria de la Encuesta Nacional de Salud 2000, con aplicación de un algoritmo conformado por técnicas serológicas treponémicas y no treponémicas, de tamizaje y confirmatorias, y se realizó un análisis estadístico para identificar los factores vinculados con la seropositividad. RESULTADOS: La seroprevalencia de anticuerpos antitreponémicos fue de 3.1% (IC95% 2.5-3.7. Las características relacionadas de modo significativo con la exposición a la infección fueron la mayor edad (RM 3.3, sexo masculino (RM 1.3, residencia en la región geográfica sur del país (RM 1.7, vivir en unión libre (RM 2.7 o ser viudo (RM 1.8, inicio de relaciones sexuales a edad temprana (RM 6.3 y, en las mujeres en particular, se identificó el antecedente de mortinatos (RM 1.8 y el informe de falta de uso del condón como método anticonceptivo (RM 14.1. CONCLUSIONES: Los hallazgos del estudio demuestran que la magnitud del antecedente de la infección por el treponema en la población mexicana adulta es considerablemente mayor respecto del que permite calcular la notificación oficial de casos de la enfermedad. Como sucede con otras infecciones de transmisión sexual, aspectos sociodemográficos, de género y las prácticas sexuales no seguras incrementan la transmisión del agente etiológico. En México existe la necesidad de reforzar la vigilancia de la infección sifilítica a través de un diagnóstico oportuno y eficaz de los casos, más su adecuado tratamiento, para coadyuvar al control del padecimiento.OBJECTIVE: To measure for the first time in a population based study the prevalence of antibodies against Treponema pallidum among the Mexican adult population and

Risk Assessment of the Main Control Room Fire Using Fire Simulations

International Nuclear Information System (INIS)

Kang, Dae Il; Kim, Kilyoo; Jang, Seung Cheol

2013-01-01

KAERI is performing a fire PSA for a reference plant, Ulchin Unit 3, as part of developing the Korean site risk profile (KSRP). Fire simulations of the MCR fire were conducted using the CFAST (Consolidated Fire Growth and Smoke Transport) model and FDS (fire dynamic simulator) to improve the uncertainty in the MCR fire risk analysis. Using the fire simulation results, the MCR abandonment risk was evaluated. Level 1 PSA (probabilistic safety assessment) results of Ulchin Unit 3 using the EPRI PRA (probabilistic risk assessment) implementation guide showed that the MCR (main control room) fire was the main contributor to the core damage frequency. Recently, U. S. NRC and EPRI developed NUREG/CR-6850 to provide state-of-the-art methods, tools, and data for the conduct of a fire PSA for a commercial NPP

Fire characteristics associated with firefighter injury on large federal wildland fires.

Science.gov (United States)

Britton, Carla; Lynch, Charles F; Torner, James; Peek-Asa, Corinne

2013-02-01

Wildland fires present many injury hazards to firefighters. We estimate injury rates and identify fire-related factors associated with injury. Data from the National Interagency Fire Center from 2003 to 2007 provided the number of injuries in which the firefighter could not return to his or her job assignment, person-days worked, and fire characteristics (year, region, season, cause, fuel type, resistance to control, and structures destroyed). We assessed fire-level risk factors of having at least one reported injury using logistic regression. Negative binomial regression was used to examine incidence rate ratios associated with fire-level risk factors. Of 867 fires, 9.5% required the most complex management and 24.7% required the next-highest level of management. Fires most often occurred in the western United States (82.8%), during the summer (69.6%), caused by lightening (54.9%). Timber was the most frequent fuel source (40.2%). Peak incident management level, person-days of exposure, and the fire's resistance to control were significantly related to the odds of a fire having at least one reported injury. However, the most complex fires had a lower injury incidence rate than less complex fires. Although fire complexity and the number of firefighters were associated with the risk for at least one reported injury, the more experienced and specialized firefighting teams had lower injury incidence. Copyright © 2013 Elsevier Inc. All rights reserved.

Fire Research Enclosure

Data.gov (United States)

Federal Laboratory Consortium — FUNCTION: Simulates submarine fires, enclosed aircraft fires, and fires in enclosures at shore facilities .DESCRIPTION: FIRE I is a pressurizable, 324 cu m(11,400 cu...

Fire protection for launch facilities using machine vision fire detection

Science.gov (United States)

Schwartz, Douglas B.

1993-02-01

Fire protection of critical space assets, including launch and fueling facilities and manned flight hardware, demands automatic sensors for continuous monitoring, and in certain high-threat areas, fast-reacting automatic suppression systems. Perhaps the most essential characteristic for these fire detection and suppression systems is high reliability; in other words, fire detectors should alarm only on actual fires and not be falsely activated by extraneous sources. Existing types of fire detectors have been greatly improved in the past decade; however, fundamental limitations of their method of operation leaves open a significant possibility of false alarms and restricts their usefulness. At the Civil Engineering Laboratory at Tyndall Air Force Base in Florida, a new type of fire detector is under development which 'sees' a fire visually, like a human being, and makes a reliable decision based on known visual characteristics of flames. Hardware prototypes of the Machine Vision (MV) Fire Detection System have undergone live fire tests and demonstrated extremely high accuracy in discriminating actual fires from false alarm sources. In fact, this technology promises to virtually eliminate false activations. This detector could be used to monitor fueling facilities, launch towers, clean rooms, and other high-value and high-risk areas. Applications can extend to space station and in-flight shuttle operations as well; fiber optics and remote camera heads enable the system to see around obstructed areas and crew compartments. The capability of the technology to distinguish fires means that fire detection can be provided even during maintenance operations, such as welding.

34 CFR 668.49 - Institutional fire safety policies and fire statistics.

Science.gov (United States)

2010-07-01

... 34 Education 3 2010-07-01 2010-07-01 false Institutional fire safety policies and fire statistics... fire statistics. (a) Additional definitions that apply to this section. Cause of fire: The factor or...; however, it does not include indirect loss, such as business interruption. (b) Annual fire safety report...

All fired up

CERN Multimedia

CERN Bulletin

2013-01-01

Members of the Directorate and their support staff took part in a fire-fighting course organised by the CERN Fire Brigade just before the end-of-year break.  The Bulletin takes a look at the fire-fighting training on offer at CERN.   At CERN the risk of fire can never be under-estimated. In order to train personnel in the use of fire extinguishers, CERN's fire training centre in Prévessin acquired a fire-simulation platform in 2012. On the morning of 17 December 2012, ten members of the CERN directorate and their support staff tried out the platform, following in the footsteps of 400 other members of the CERN community who had already attended the course. The participants were welcomed to the training centre by Gilles Colin, a fire-fighter and instructor, who gave them a 30-minute introduction to general safety and the different types of fire and fire extinguishers, followed by an hour of practical instruction in the simulation facility. There they were able to pract...

Fire simulation in radioactive waste disposal and the radiation risk associated

International Nuclear Information System (INIS)

Domingos, Érica Nascimento

2018-01-01

An atmospheric dispersion of radioactive material is one of the possible consequences of an accident scenario in nuclear installations, radiative and radioactive waste deposit. Taking into account a possibility of this release of radioactive material into the atmosphere this work proposes a modeling of the atmospheric dispersion from a fire scenario in a deposit of radioactive waste of low and middle level of radiation varying the amount of inventory released in the fire. For this simulation was adopted the software of physical codes of medical health, the HotSpot Health Physics Codes which uses the Gaussian model to calculate an atmospheric dispersion based on the Pasquill atmospheric stability classes. This software calculates a total effective dose in relation to distance, such as a compromised dose in a list of specific organs, among them the lung, object of work study for calculating the risk of cancer associated with a low dose of radiation. The radiological risk calculation is held by the BEIR V model, Biological Effects of Ionizing Radiations, one of the models to estimate the relative risk of cancer induced by ionizing radiation. (author)

Simulation of fire in a deposit of radioactive waste and the radiological risk associated to this scenario

International Nuclear Information System (INIS)

Domingos, Érica Nascimento; Lima, Zelmo Rodrigues de; Aguiar, Laís Alencar de

2017-01-01

A fire at radioactive waste deposit can result in significant damage as well as serious risks to the environment and the health of the general public. The CNEN (National Commission of Nuclear Energy) norms have fire protection regulations criteria and requirements to prevent the occurrence, neutralize the action and minimize the effects of the fire on the radioactive material present on the plant. These norms it is for to avoid or limit to the lowest possible levels the effects of ionizing radiation or toxic substances on humans and the environment. Before a possible fire containing radioactive material is necessary information that can estimate the dose in which the population will be submitted. In this work the proposal is to simulate a fire scenario containing radioactive material using Hotspot Health Physics simulation code and to identify the radiological risk of cancer in the respiratory system associated with this scenario using the BEIR V model. (author)

Simulation of fire in a deposit of radioactive waste and the radiological risk associated to this scenario

Energy Technology Data Exchange (ETDEWEB)

Domingos, Érica Nascimento; Lima, Zelmo Rodrigues de, E-mail: erica.ndomingos@gmail.com, E-mail: zrlima@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Aguiar, Laís Alencar de, E-mail: laguiars@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2017-07-01

A fire at radioactive waste deposit can result in significant damage as well as serious risks to the environment and the health of the general public. The CNEN (National Commission of Nuclear Energy) norms have fire protection regulations criteria and requirements to prevent the occurrence, neutralize the action and minimize the effects of the fire on the radioactive material present on the plant. These norms it is for to avoid or limit to the lowest possible levels the effects of ionizing radiation or toxic substances on humans and the environment. Before a possible fire containing radioactive material is necessary information that can estimate the dose in which the population will be submitted. In this work the proposal is to simulate a fire scenario containing radioactive material using Hotspot Health Physics simulation code and to identify the radiological risk of cancer in the respiratory system associated with this scenario using the BEIR V model. (author)

Mean composite fire severity metrics computed with Google Earth Engine offer improved accuracy and expanded mapping potential

Science.gov (United States)

Parks, Sean; Holsinger, Lisa M.; Voss, Morgan; Loehman, Rachel A.; Robinson, Nathaniel P.

2018-01-01

Landsat-based fire severity datasets are an invaluable resource for monitoring and research purposes. These gridded fire severity datasets are generally produced with pre-and post-fire imagery to estimate the degree of fire-induced ecological change. Here, we introduce methods to produce three Landsat-based fire severity metrics using the Google Earth Engine (GEE) platform: the delta normalized burn ratio (dNBR), the relativized delta normalized burn ratio (RdNBR), and the relativized burn ratio (RBR). Our methods do not rely on time-consuming a priori scene selection and instead use a mean compositing approach in which all valid pixels (e.g. cloud-free) over a pre-specified date range (pre- and post-fire) are stacked and the mean value for each pixel over each stack is used to produce the resulting fire severity datasets. This approach demonstrates that fire severity datasets can be produced with relative ease and speed compared the standard approach in which one pre-fire and post-fire scene are judiciously identified and used to produce fire severity datasets. We also validate the GEE-derived fire severity metrics using field-based fire severity plots for 18 fires in the western US. These validations are compared to Landsat-based fire severity datasets produced using only one pre- and post-fire scene, which has been the standard approach in producing such datasets since their inception. Results indicate that the GEE-derived fire severity datasets show improved validation statistics compared to parallel versions in which only one pre-fire and post-fire scene are used. We provide code and a sample geospatial fire history layer to produce dNBR, RdNBR, and RBR for the 18 fires we evaluated. Although our approach requires that a geospatial fire history layer (i.e. fire perimeters) be produced independently and prior to applying our methods, we suggest our GEE methodology can reasonably be implemented on hundreds to thousands of fires, thereby increasing opportunities

Tunnel fire dynamics

CERN Document Server

Ingason, Haukur; Lönnermark, Anders

2015-01-01

This book covers a wide range of issues in fire safety engineering in tunnels, describes the phenomena related to tunnel fire dynamics, presents state-of-the-art research, and gives detailed solutions to these major issues. Examples for calculations are provided. The aim is to significantly improve the understanding of fire safety engineering in tunnels. Chapters on fuel and ventilation control, combustion products, gas temperatures, heat fluxes, smoke stratification, visibility, tenability, design fire curves, heat release, fire suppression and detection, CFD modeling, and scaling techniques all equip readers to create their own fire safety plans for tunnels. This book should be purchased by any engineer or public official with responsibility for tunnels. It would also be of interest to many fire protection engineers as an application of evolving technical principles of fire safety.

Convective effects in a regulatory and proposed fire model

International Nuclear Information System (INIS)

Wix, S.D.; Hohnstreiter, G.F.

1995-01-01

Radiation is the dominant mode of heat transfer in large fires. However, convection can be as much as 10 to 20 percent of the total heat transfer to an object in a large fire. The current radioactive material transportation packaging regulations include convection as a mode of heat transfer in the accident condition scenario. The current International Atomic Energy Agency Safety Series 6 packaging regulation states ''the convection coefficient shall be that value which the designer can justify if the package were exposed to the specified fire''. The current Title 10, Code of Federal Regulations, Part 71 (10CFR71) packaging regulation states ''when significant, convection heat input must be included on the basis of still, ambient air at 800 degrees C (1475 degrees F)''. Two questions that can arise in an analysts mind from an examination of the packaging regulations is whether convection is significant and whether convection should be included in the design analysis of a radioactive materials transportation container. The objective of this study is to examine the convective effects on an actual radioactive materials transportation package using a regulatory and a proposed thermal boundary condition

Fire spread simulation of a full scale cable tunnel

International Nuclear Information System (INIS)

Huhtanen, R.

1999-11-01

A fire simulation of a full scale tunnel was performed by using the commercial code EFFLUENT as the simulation platform. Estimation was made for fire spread on the stacked cable trays, possibility of fire spread to the cable trays on the opposite wall of the tunnel, detection time of smoke detectors in the smouldering phase and response of sprinkler heads in the flaming phase. According to the simulation, the rise of temperature in the smouldering phase is minimal, only of the order 1 deg C. The estimates of optical density of smoke show that normal smoke detectors should give an alarm within 2-4 minutes from the beginning of the smouldering phase, depending on the distance to the detector (in this case it was assumed that the thermal source connected to the smoke source was 50 W). The flow conditions at smoke detectors may be challenging, because the velocity magnitude is rather low at this phase. At 4 minutes the maximum velocity at the detectors is 0.12 m/s. During the flaming phase (beginning from 11 minutes) fire spreads on the stacked cable trays in an expected way, although the ignition criterion seems to perform poorly when ignition of new objects is considered. The Upper cable trays are forced to ignite by boundary condition definitions according to the experience found from ti full scale experiment and an earlier simulation. After 30 minutes the hot layer in the room becomes so hot that it speeds up the fire spread and the rate of heat release of burning objects. Further, the hot layer ignites the cable trays on the opposite wall of the tunnel after 45 minutes. It is estimated that the sprinkler heads would be activated at 20-22 minutes near the fire source and at 24-28 minutes little further from the fire source when fast sprinkler heads are used. The slow heads are activated between 26-32 minutes. (orig.)

Characterization of potential fire regimes: applying landscape ecology to fire management in Mexico

Science.gov (United States)

Jardel, E.; Alvarado, E.; Perez-Salicrup, D.; Morfín-Rios, J.

2013-05-01

Knowledge and understanding of fire regimes is fundamental to design sound fire management practices. The high ecosystem diversity of Mexico offers a great challenge to characterize the fire regime variation at the landscape level. A conceptual model was developed considering the main factors controlling fire regimes: climate and vegetation cover. We classified landscape units combining bioclimatic zones from the Holdridge life-zone system and actual vegetation cover. Since bioclimatic conditions control primary productivity and biomass accumulation (potential fuel), each landscape unit was considered as a fuel bed with a particular fire intensity and behavior potential. Climate is also a determinant factor of post-fire recovery rates of fuel beds, and climate seasonality (length of the dry and wet seasons) influences fire probability (available fuel and ignition efficiency). These two factors influence potential fire frequency. Potential fire severity can be inferred from fire frequency, fire intensity and behavior, and vegetation composition and structure. Based in the conceptual model, an exhaustive literature review and expert opinion, we developed rules to assign a potential fire regime (PFR) defined by frequency, intensity and severity (i.e. fire regime) to each bioclimatic-vegetation landscape unit. Three groups and eight types of potential fire regimes were identified. In Group A are fire-prone ecosystems with frequent low severity surface fires in grasslands (PFR type I) or forests with long dry season (II) and infrequent high-severity fires in chaparral (III), wet temperate forests (IV, fire restricted by humidity), and dry temperate forests (V, fire restricted by fuel recovery rate). Group B includes fire-reluctant ecosystems with very infrequent or occasional mixed severity surface fires limited by moisture in tropical rain forests (VI) or fuel availability in seasonally dry tropical forests (VII). Group C and PFR VIII include fire-free environments

The role of fuels for understanding fire behavior and fire effects

Science.gov (United States)

E. Louise Loudermilk; J. Kevin Hiers; Joseph J. O' Brien

2018-01-01

Fire ecology, which has emerged as a critical discipline, links the complex interactions that occur between fire regimes and ecosystems. The ecology of fuels, a first principle in fire ecology, identifies feedbacks between vegetation and fire behavior-a cyclic process that starts with fuels influencing fire behavior, which in turn governs patterns of postfire...

EPR-technical codes - a common basis for the EPR