Abstract
Liquids and solvents in industrial products produce flammable vapor which, when mixed with air, can ignite or explode. The ease by which those liquids produce flammable vapors depends on their flashpoints which allow them to be categorized according to the fire hazard they exhibit in their normal use. In this chapter, a novel approach for the classification of liquids is proposed. The proposed approach relies on the use of a vector network analyzer, a patch antenna, and a group of classifiers. In this study, random forest and REPTree algorithms are preferred as classifers. As proven in the study, random forest algorithm can provide higher accuracy than REPTree algorithm in the classification of hazardous liquids. A prototype system is currently under development in order to integrate the components of the proposed approach into a single unit. It is expected that the prototype system will quickly and reliable make a non-contact classification of liquids in different kinds of bottles.
TopIntroduction
An explosive liquid, commonly known as a flammable liquid, is one which can catch fire. As well as fuels, examples of explosive liquids are solvents used in paints, inks and adhesives. Because they all produce combustible vapor which could ignite when mixed with oxygen. Flashpoint tests are used to categorize flammable liquids by measuring the temperature at which the liquids would ignite when an ignition source was applied. Extremely flammable liquids have flashpoints lower than 0°C, highly flammable liquids have flashpoints below 21°C, and flammable liquids have flashpoints equal or greater than 21°C and less than or equal to 55°C. Explosive atmospheres can be caused by flammable gases, vapors or mists or by combustible dusts. If there is enough of such a substance, mixed with air, a source of ignition can easily cause an explosion.
If high-risk substances are not handled, used and transported properly and safely, they can cause a number of different hazards. Some of the hazards are fire, explosion, sudden release of pressure and reactivity. As well as these, overexposure to hazardous substances can result in some health hazards varying from minor ones, such as a headache or mild skin rash, to serious ones, such as skin burns from a contact with corrosive chemicals. Too much or prolonged exposure to some hazardous substances could cause allergic-type reactions, organ damage, cancer, or even death, too. The risks associated with hazardous substances are not just to the individuals working with them, with people in the neighborhood, too. Examples of these are a major spill of a hazardous chemical or releases of toxic gases after a fire or explosion.
Although hazardous substances are toxic, corrosive, and/or oxidizing and their production, storage and transportation is risky, they are essential in the economic growth of some developing countries (Hu & Raymond, 2004). However, some solutions are available such as performing tasks without using hazardous substances, substituting them with less hazardous ones, keeping the areas where hazardous substances are used separate, or purging or ventilating those areas separately. In the areas where hazardous substances are produced, used or transported, using respirators, goggles and gloves should be a must for the employees and those areas should be monitored with appropriate devices regularly. Finally, training of the employees for handling and safety procedures and practices plays a key role. Even all these are critical solutions for the related industries; there is still a great risk in crowded places. Because hazardous substances are used to make explosives and these explosives can be used for terrorist attacks. Therefore, liquid explosive detectors are used in train stations, airports and shopping malls to ensure an optimal level of security. They are effective solutions up to some degree; however, they sometimes create false alarms due to the misclassification of the liquids, especially in non-contact detection. In this chapter, after discussing the related topic, the details of a non-contact liquid scanner are given and its performance when different classification algorithms are used is shown.
Key Terms in this Chapter
Patch Antenna: It is a type of radio antenna mounted on a flat surface.
Microwave: It is a form of electromagnetic radiation with wavelengths ranging from about 1 millimeter to 1 meter and with frequencies between 300 MHz and 300 GHz.
Classification Algorithm: It maps a given input data to a specific category.
Safety Data Sheet: It is a document that lists information relating to occupational safety and health for the use of various substances and products.
Non-Contact Detection: A process used to remotely detect a material without a physical contact.
Liquid Explosive Detectors: It is used to detect explosive substances in liquid form and is generally used at crowded places such as airports, train stations or shopping malls.