Polyploidy but Not Range Size Is Associated With Seed and Seedling Traits That Affect Performance of Pomaderris Species

Ploidy and species range size or threat status have been linked to variation in phenotypic and phenological seed and seedling traits, including seed size, germination rate (speed) and seedling stature. There is surprisingly little known about the ecological outcomes of relationships between ploidy, key plant traits and the drivers of range size. Here we determined whether ploidy and range size in Pomaderris, a genus of shrubs that includes many threatened species, are associated with variation in seed and seedling traits that might limit the regeneration performance of obligate seeders in fire-prone systems. We experimentally quantified seed dormancy and germination processes using fire-related heat treatments and evaluated seedling performance under drought stress. We also examined the association of seed size with other seed and seedling traits. Polyploids had bigger seeds, a faster germination rate and larger and taller seedlings than diploids. There was a lack of any clear relationship between range size and seed or seedling traits. The ploidy effects observed for many traits are likely to be indirect and associated with the underlying seed size differences. These findings indicate that there is a higher potential competitive advantage in polyploid than diploid Pomaderris during regeneration, a critical stage in the post-fire environment. This insight to the regeneration phase may need to be considered when planning and prioritising management of threatened species.

Building Fire Evacuation: An IoT-Aided Perspective in the 5G Era

Complex and tall buildings have been constructed in many cities recently. Fire safety should be a major concern of building designers, engineers, and governments. Previous fire experience has made us understand the importance of acquiring fire-ground information to facilitate firefighting operations, evacuation processes, rescues, etc. Recently, the rapid advancement in Information Technology, Data Analytics, and other detection and monitoring systems has provided the basis for fire safety researchers to re-think fire safety strategies in the built environment. Amongst all fire safety studies, evacuation in tall buildings, including elevator evacuations, has attracted much attention. IoT-aided building fire evacuation is a new concept of the building evacuation mode, which improves the building evacuation process by making decisions of escape based on the real-time fire-ground information, such as the fire environment and occupant situations. Focusing on IoT applications in building fire evacuation, this paper explores the advantages and insufficiencies of current smart building fire evacuation systems. A conceptual design of an IoT-aided building fire evacuation control system is described. The system is introduced in the sequence of information needs, information sources and data transmission, and potential services and applications. Finally, new insights into promising 5G technologies for future building fire evacuations are discussed.

Modeling Fire Spread in a Real-Time Coupled Atmospheric-Vegetation Fire: An Analytical Approach

The ability to analyse the rate of fire spread outbreak in a real-time coupled Atmospheric-vegetation fire has become increasingly vital as forest fire fighters are building diverse kinds of models to combat the dangers/effects of fire spread across a given fire vicinity. This paper theoretically examines the analysis of fire spread in a real fire environment. A partial differential equations (PDE) governing the phenomenon is presented. The analytical solution of the model is obtained via direct integration and eigenfunction expansion technique, which displays the influence of the parameters involved in the system. The effect of change in parameters such as Frank-Kamenetskii number, Radiation number, Peclet energy number and Activation energy number are presented graphically and discussed. The results obtained show that Frank-Kamenetskii number, Radiation number, Peclet energy number, and Activation energy number all reduced transient state temperature.

Effect of Seedling Provenance and Site Heterogeneity on Abies cephalonica Performance in a Post-Fire Environment

Reforestation constitutes a challenge in post-fire ecosystem restoration, although there are limitations such as species and genotype selection, planting and management design, and environmental conditions. In the present study, the basic issue is the longevity of Abies cephalonica Loudon—the Greek fir seedlings planted extensively in Parnitha National Park (Central Greece), located near the metropolitan city of Athens, following the large-scale wildfire of 2007. Seedling performance was assessed for a 3-year monitoring period (2013–2015) through the establishment of 8 permanent transects, including 400 seedlings at the burned, reforested sites. According to the long-term reforestation project, two seedling provenances were used: (a) from Mt. Mainalon (South Greece, Vytina provenance) and (b) the local one from Mt. Parnitha. Both provenances showed a relatively successful survival rate reaching, in average, 73.8%, with the first summer after planting being crucial for seedling survival. The overall mean seedling height was 39.2 ± 1.1 cm, with a mean crown diameter of 47.3 ± 1.4 cm in the last monitoring survey. Although Parnitha seedlings seem to perform better in terms of growth, seedling performance in both provenances was affected by reforestation site characteristics, mainly altitude and aspect. Approximately one third of seedlings exhibited damage in their crown architecture (29.8%), while apical bud damage was less extensive (12.2%) in the final field measurement. Data indicate that seedling performance has proved to be quite promising for post-fire restoration, although long-term monitoring data should be considered.

Experimental Study on the Availability of Fire Detection Using Gas Sensors for Air Quality Measurement

This study tested gas sensors used to measure indoor air quality to explore the feasibility of using them as detection sensors in case of fire. A B-class fire environment was implemented in the compartment (ISO 9705 standard fire room), and four types of high- and low- accuracy and priced gas sensors (Carbon monoxide, carbon dioxide, methane, t-VOC) used for indoor air quality measurement were installed. From ignition of the fuel to alarming of the heat detector, the responses from the sensors were analyzed. The results revealed the following: 1) Among the four types of sensors, CO and t-VOC sensors were effective as fire detection sensors in terms of their concentration increase and response time. 2) Low-accuracy CO₂ and CH₄ sensors were not effective in fire detection as they responded late relatively to CO and t-VOC sensors. 3) It was confirmed that low-accuracy gas sensors are feasible for use for fire detection in that they showed valid increase in concentration before the heat detector alarms. However, as only liquid combustible (Heptane) was applied as a fire source, analysis in an environment where different types of combustibles are used will be necessary in the future.

Research on the Mechanical Characteristics of H-section Steel Frame under the Action of Thermo Mechanical Coupling

The research on the mechanical characteristics of concrete-filled steel tubular composite frame under high temperature fire environment is one of the research hotspots. In this paper, the finite element simulation software is used to analyze the concrete-filled steel tubular composite frame structure. The failure mode of the flexural deformation of the composite frame structure under high temperature fire environment is introduced. The simulation results of the deformation and displacement of the single-layer single span and two-layer two-span composite frame structure are deeply studied, including the different temperature field, structural field, structural field of each beam and column The results show that: with the temperature rising, the horizontal plastic strain, vertical displacement and local plastic region of beam and column are redistributed and changed in high temperature fire environment, and the flexural effect of two-story two-span concrete-filled steel tubular composite frame under different fire positions is analyzed. The results show that: with the temperature rising, the horizontal plastic strain at the concentrated load is not the results show that the deflection and deformation redistribution are obvious, and the deflection and deformation redistribution are obvious at the joint points of beams and columns. Finally, a mechanism is formed and destroyed. The flexure effect of mode 1 is larger than that of condition 2, which indicates that the flexural effect of two-story two span CFST composite frame under full cross-section fire is larger than that of condition 2 It should be better. The research results can provide reference value for the reinforcement and repair of CFST composite frame under high temperature fire.