A Note on Mathematical Modelling of Elliptical Fire Propagation

Mathematical modelling of forest fire propagation in time plays a key role in existing fire propagation predicting systems. Such systems are capable of simulating the growth of fire front in time and space and predicting spatial and temporal fire behaviour. In our previous papers, we studied mathematical foundations of the elliptical fire propagation model implemented in several advanced simulation systems.The model is based on Huygens' principle applied on fire propagation assuming locally elliptical fire spread. However, in the literature various other mathematical representations of local fire propagation have been reported, such as double ellipse, lemniskata, oval shape, tear shape, and others. Such types of local fire propagation have been experimentally observed in certain conditions during laboratory and field fires. In this paper, we demonstrate several simple examples of fire propagation corresponding both to the elliptical and non-elliptical local fire propagation in homogeneous conditions

Parallel Computation of Smoke Movement During a Car Park Fire

In this paper the use of Fire Dynamics Simulator (FDS) for parallel computer simulation of the smoke movement during a fire of two passenger cars in an underground car park is investigated. The simulations were executed on a high-performance computer cluster. A specific problem of FDS parallel computation using Message-Passing Interface (MPI) is a separate solution of governing equations on computational subdomains causing a loss of accuracy. Therefore, the impact of parallelisation on simulation accuracy in the case of using a greater number of computational cores of the computer cluster is studied with the aim to increase the computational performance and enable practical application of such simulations for fire safety measures. The geometrical model and material properties of the cars used in the simulation have been verified by a full-scale fire experiment in open air. We describe the results of a series of simulations of several fire scenarios with different numbers of parked cars and ventilation configurations and determine times and locations at which conditions in the car park become untenable for human life. The simulation indicates that proper ventilation prolongs tenable conditions by several minutes

Parallel Computer Simulation of Fire in Road Tunnel and People Evacuation

Advances in CFD (Computational Fluid Dynamics) and significant increase of computational power of current computers have led to widespread use of CFD in aerodynamics, fluid dynamics, combustion engineering and other academic disciplines. One of such disciplines is computer modelling and simulation of fire in human structures. Fire is a very complicated and complex phenomenon. Fire research deals with such processes as combustion, radiation, heat transfer, turbulence, fluid dynamics, and other physical and chemical processes. Several advanced fire and smoke simulation systems have been developed to solve various aspects of fire safety in various conditions and environments. In this paper, the use of parallel version of the CFD simulator FDS (Fire Dynamics Simulator) for the simulation of fire spread and smoke development in a short road tunnel is described. In order to study the impact of the computational domain decomposition on the accuracy and reliability of simulation results, several simulations of a chosen fire scenario ran on the HP blade cluster utilizing different numbers of processors. The obtained parameters of fire and smoke were used to investigate the influence of the fire on people evacuation in the tunnel with active ventilation for a given traffic situation

ON DERIVATIVES ESTIMATION OF SMOOTHED DIGITAL CURVES

In this paper new linear operators for the first derivatives estimation of smoothed digital curves are presented. They correspond to digital curves smoothing by various non-negative kernels

Modelling of impact of road tunnel fire on evacuation

Požiar auta v cestnom tuneli patrí k mimoriadnym udalostiam, ktoré môžu zapríčiniť veľké materiálne škody a poškodenie tunela, jeho následnú odstávku a ohroziť život a zdravie osôb v tuneli. V tomto príspevku ilustrujeme počítačovú simuláciu požiaru a jeho vplyvu na evakuáciu osôb vo fiktívnom jednosmernom cestnom tuneli s pozdĺžnym vetraním. Na simuláciu požiaru a modelovanie evakuácie je použitý programový systém FDS (Fire Dynamics Simulator), ktorého súčasťou je evakuačný modul Evac. Priamy prístup k výsledkom simulácie priebehu požiaru umožňuje systému modelovať vplyv požiaru na individuálne a skupinové správanie a únikové stratégie evakuovaných osôb.Car fire in road tunnel belongs to emergency events which can cause large material damages and tunnel shut down. Such fire can endanger people’s lives and health. In this paper, computer simulation of fire and its impact on evacuation in a single-directional road tunnel with longitudinal ventilation is illustrated. FDS (Fire Dynamics Simulator) with Evac (evacuation module) is used for simulation of fire and modelling evacuation in the tunnel. Direct access to simulation results of fire course enables the system to model impact of fire on individual and group behaviour and escape strategies of passengers

Measurements and fire simulation models in road tunnels

Ventilation system of road tunnel is one of the most important parts of the tunnel safety equipment, especially in view of the emergency event in the tunnel with fire. Last year we presented the testing and the first in situ measurements of our project entitled “Models of formation and spread of fire to increase safety of road tunnels”. With regard to our project schedule we performed also the second in situ experiment. Other part of this paper deals with computer simulations of fires of a selected Slovak road tunnel

Measurements and fire simulation models in road tunnels

Ventilation system of road tunnel is one of the most important parts of the tunnel safety equipment, especially in view of the emergency event in the tunnel with fire. Last year we presented the testing and the first in situ measurements of our project entitled “Models of formation and spread of fire to increase safety of road tunnels”. With regard to our project schedule we performed also the second in situ experiment. Other part of this paper deals with computer simulations of fires of a selected Slovak road tunnel

Evaluation of New Polyclonal Antibody Developed for Serological Diagnostics of Tomato Mosaic Virus

Plant viruses threaten agricultural production by reducing the yield, quality, and economical benefits. Tomato mosaic virus (ToMV) from the genus Tobamovirus causes serious losses in the quantity and quality of tomato production. The management of plant protection is very difficult, mainly due to the vector-less transmission of ToMV. Resistant breeding generally has low effectiveness. The most practical approach is the use of a rapid diagnostic assay of the virus’ presence before the symptoms occur in plants, followed by the eradication of virus-infected plants. Such approaches also include serological detection methods (ELISA and Western immunoblotting), where antibodies need to be developed for an immunochemical reaction. The development and characterization of polyclonal antibodies for the detection of ToMV with appropriate parameters (sensitivity, specificity, and cross-reactivity) were the subjects of this study. A new polyclonal antibody, AB-1, was developed in immunized rabbits using the modified oligopeptides with antigenic potential (sequences are revealed) derived from the coat protein of ToMV SL-1. the developed polyclonal antibody. AB-1, showed higher sensitivity when compared with commercially available analogs. It also detected ToMV in infected pepper and eggplant plants, and detected another two tobamoviruses (TMV and PMMoV) and ToMV in soil rhizosphere samples and root residues, even two years after the cultivation of the infected tomato plant

Introduction of a synthetic Thermococcus-derived α-amlyase gene into barley genome for increased enzyme thermostability in grains

Background: The enzymes utilized in the process of beer production are generally sensitive to higher temperatures. About 60% of them are deactivated in drying the malt that limits the utilization of starting material in the fermentation process. Gene transfer from thermophilic bacteria is a promising tool for producing barley grains harboring thermotolerant enzymes. Results: Gene for α-amylase from hydrothermal Thermococcus, optimally active at 75–85°C and pH between 5.0 and 5.5, was adapted in silico to barley codon usage. The corresponding sequence was put under control of the endosperm-specific promoter 1Dx5 and after synthesis and cloning transferred into barley by biolistics. In addition to model cultivar Golden Promise we transformed three Slovak barley cultivars Pribina, Levan and Nitran, and transgenic plants were obtained. Expression of the ~50 kDa active recombinant enzyme in grains of cvs. Pribina and Nitran resulted in retaining up to 9.39% of enzyme activity upon heating to 75°C, which is more than 4 times higher compared to non-transgenic controls. In the model cv. Golden Promise the grain α-amylase activity upon heating was above 9% either, however, the effects of the introduced enzyme were less pronounced (only 1.22 fold difference compared with non-transgenic barley). Conclusions: Expression of the synthetic gene in barley enhanced the residual α-amylase activity in grains at high temperatures. Keywords: Amylopectin, Amylose, Beer, Fermentation, Gene transfer, Glutenin, Hordeum, Promoter, Seed-directed expression, Synthetic gene, Thermotolerant bacteri