Optimization of Foamed Polyurethane/Ground Tire Rubber Composites Manufacturing

The development of the automotive sector and the increasing number of vehicles all over the world poses multiple threats to the environment. One of them, probably not so emphasized as others, is the enormous amount of post-consumer car tires. Due to the potential fire threat, waste tires are considered as dangerous waste, which should not be landfilled, so it is essential to develop efficient methods of their utilization. One of the possibilities is their shredding and application of resulting ground tire rubber (GTR) as filler for polymer composites, which could take advantage of the excellent mechanical performance of car tires. Nevertheless, due to the poor compatibility with majority of polymer matrices, prior to the application, surface of GTR particles should be modified and activated. In the presented work, the introduction of thermo-mechanically modified GTR into flexible foamed polyurethane matrix was analyzed. Isocyanates can be found among the compounds applied during manufacturing of polyurethane foams, which are able to react and generate covalent bonds with the functional groups present on the surface of modified GTR. Such an effect can noticeably enhance the interfacial interactions and boost up the mechanical performance. Nevertheless, it requires the adjustment of formulations used during manufacturing of foams. Therefore, for better understanding of the process foams with varying isocyanate index (from 0.8 to 1.2) were prepared with and without taking into account the possible interactions with functional groups of GTR. For comparison, an unfilled matrix and composite containing deactivated GTR were also prepared.

Hangar fire detection alarm with algorithm for extinguisher

A fire alarm is a high-performance system that detects smoke, heat or flames and actuates fire suppression system, for the protection of lives and property. It is employed in aircraft hangars for the protection of aircraft, personnel as well as the hangar structure. The need for a fire alarm in a hangar with algorithm for extinguishers cannot be overemphasized. The structure of the hangar building, type of aircraft housed in the hangar and activities carried out at the hangar such as inspections, overhauls and modifications of aircraft, determine the type of fire alarm to be used, whether it should be automatic or manual [2]. The detection employed, be it smoke detection, heat sensing or both and the process of extinguishing in the face of a fire threat or hazard is equally important. The effectiveness of the alarm is dependent on genuine alerts and not false alarm triggers, hence in this research paper, the employment of intelligent detection using comparators in programmed IC, the Micro-controller, was interfaced with a 555 Timer, a multi-vibrator for generating aural sound for alarm, LCD Display for indicated readings as well as algorithm for extinguishing using water or foam via sprinklers. The basic work started with a block diagram representation, thereafter, individual subsystems, which form the building blocks were analyzed and the components parts identified. A circuit diagram for the project was analyzed and built using Proteus. This was simulated and found to be achievable, hence a program was written in C++ for the micro-controller using Arduino Language known as the source code. The results show hangar fire detection alarm with algorithm for extinguishing and was investigated as an effective means of suppressing fire threat in the hangar [4].

Surviving the Australian Black Summer bushfires: a veterinary perspective

The Australian summer of 2019–2020 has become known as ‘the Black Summer’. The fires burned an estimated 186 000 km2; destroyed over 5900 buildings and killed at least 34 people. Nearly 80% of Australians were affected either directly or indirectly by the Black Summer bushfires. One of the lessons from this disaster is that everyone at risk has a responsibility to manage their own response to an emergency, there are simply not enough resources to be able to defend every house and every community. Prior preparation enables a community level response to an emergency that can improve outcomes in a disaster situation. This article provides an insight into the Black Summer fires from two different veterinary viewpoints, a practice partner whose hospitals came under direct fire threat, and a veterinarian volunteer firefighter who fought these fires on the frontline. The lessons learned from these unprecedented fires are applicable to all veterinarians. In a world where natural disasters are becoming the new norm, preparedness is the key to successfully managing these challenges.

Application of risk management system (GRDR) on Chilean tunnels La Pólvora and Subway Line 3 Santiago

<p>During last 5 years, the Ministry of Public Works and the Pontificia Universidad Católica de Valparaíso are developing a Risk Management System applied in several road infrastructures called GRDR. This methodology is focus on the inspection on: 1. Structures in order to identify the vulnerability; 2. environmental conditions with the aim to identify the exposure and hazard. The relations between these indexes use an algorithm to apply the weight on the parameters. Currently, the deterministics inspection use a comprehensive management program provides an index of vulnerability (Performance indicators) in structures as bridges and pavements. But it is not included the hazard or exposure index. This paper delivers the first index of hazards and exposure related with seismic, flooding and fire threat applied on the Risk Management System (GRDR), with an implementation on two main Chilean structures, namely: La Pólvora Tunnel T3, a medium long span structure, located at the Region Valparaiso, in the maritime and urban area exposed in the last years an earthquakes and fire hazards, and Subway Line 3, located in Santiago, the new station in service during 2018 with a high users and hazard by earthquake and flooding.</p>

Wind Energy Implementation to Mitigate Wildfire Risk and Preemptive Blackouts

Damages caused by wildfires in California due to transmission line failures have increased significantly in recent years. Curtailment of electric service in areas under fire threat has been implemented to avoid these wildfires. Results from this research indicated that 24% of California’s cities are at risk of wildfire, while 52% are at risk of blackout. These blackouts have resulted in significant financial losses and risk to life and health. Undergrounding current transmission lines has been proposed as a long-term solution. However, undergrounding lines would take decades to complete and increase average monthly electric bills from $80 to $260. This research investigated shortening the length of the electricity supply chain, supplying affected communities with onshore and offshore wind energy. Results showed good wind energy potential in locations near affected cities. Distance analyses revealed that more than two hundred cities (population 5.5 million) can be served by existing wind farms located at less than 50 km. Future offshore wind turbines could generate high power output (capacity factor >50% for significant periods). An analysis of diverse locations along California’s coast indicated that just one offshore wind farm could serve more than a hundred cities with cumulative population larger than one million.

PE and ETFE wire insulation flame morphologies and spread rates under subatmospheric pressures

Understanding the effects of pressure and oxygen concentration on the flame spread behaviors of electrical wires is crucial for establishing fire safety strategies for plateau cities, aircraft, and spacecraft. During the combustion, the polymeric coating first liquefies to form molten agglomerations, after which these droplets boil to release combustible gases that propagate the combustion process, which brings a potential fire threat. To better evaluate this fire risk, the flame spread of polyethylene (PE) and ethylene tetrafluoroethylene (ETFE)-insulated nichrome wires was investigated in a subatmospheric cabin. During the combustion of the insulation, the PE flame always presents a closed teardrop-like structure, while at the limiting oxygen concentration condition, the ETFE flame presents an asymmetric pentagram-like structure due to uneven heat losses. In this experiment, dripping was exhibited only by the PE insulation mainly because of the difference in surface tension. When the oxygen concentration was raised from 21% to 30%, the critical pressure for dripping shifts from 60 kPa to 38 kPa. Air pressure has a slight negative effect on flame spread rates, because, at lower pressure, the burning rate is lower, but the heat loss and convective and radiant heats of the flame decrease.

Comparative Analysis of Methane Concentration Near the Junction of the Longwall and Top Road

Mining of longwalls ventilated by the „U” method is willingly applied in Polish coal-mines due to low costs of workings maintenance, low costs of ventilation and a lower fire threat because of a limited flow of air through goafs. However, such a way of ventilation may pose an increased risk of methane explosion. For this reason, the “U” ventilation has been limited in longwalls with methane risk. The mining regulations in force provide that ventilation methane-bearing capacity, i.e. the intensity of methane flow into the ventilation air cannot exceed 20 m3 CH4/min. The regulations also provide that in the event the absolute methane-bearing capacity, i.e. a sum of methane released to the ventilation air and captured by the methane drainage system is higher than 25 m3 CH4/min and the “U” method of ventilation is applied, the effectiveness of methane drainage should be minimum 50% in relation to the forecast absolute methane-bearing capacity. To streamline the process of ventilation near the junction of the longwall and the gallery carrying off the used air, auxiliary ventilation means are applied, such as a ventilation partition, a ventube – which supplies air without methane or with a low concentration of methane, injectors etc. Application of these means is limited by the cross-section of the heading carrying off the air from the longwall. Deformations of the ventilating roadway, which is usually located in the one-sided vicinity of goafs, may prevent the use of a ventilation partition, which has a negative influence on the conditions of ventilating the junction of the longwall and ventilating roadway. The author of the article also refers to such conditions, presenting average values and maximum concentrations of methane concentrations recorded with four methane concentration sensors, located in the vicinity of the junction of the longwall and ventilating roadway.

An unorthodox, new endemic species in New Caledonian Marsdenia (Apocynaceae, Asclepiadoideae, Marsdenieae)

In the course of the writing of the Flore de la Nouvelle-Calédonie treatment for Asclepiadoideae, Periplocoideae and Secamonoideae, several new species have already arisen partly due to more intensive field work and to a renewed interest in this group of plants. In December 2018, another striking and unorthodox new species was spotted and collected on the flanks of the Kopéto massif mining site. Because this new species has morphological characters from three genera (Dischidia, Gymnema and Marsdenia), further studies, especially molecular, were needed to assess its relationships. These studies show it as a member of one of the New Caledonian Marsdenia subclades. We herein propose to describe it as Marsdenia goromotoorum Gâteblé, Fleurot, Meve & Liede, the only species of Marsdenia in New Caledonia lacking both corolline and gynostegial coronas. It is a micro-endemic species with pinkish-red tubular flowers, growing on serpentines and known from only eight plants. Due to the anthropogenic fire threat, we propose to consider it as Critically Endangered.