Sharif Digital Repository

Fire phenomenon and its hazards through urbun transportation systems like subway is a major debate in management of these territories. Recently, varios factors, such as great deal of passengers whom travel by these systems, financial damages and psychological disorders due to fire accidents resulte in noticeable investigation to prevent and reduce these subjects. In this research, simulating of railcar fire has been conducted to estimate the amount of heat release rate (HRR) and parameters which affect on it by modelling behavior of combustible materials inside railcar. As regards to materials which are available inside railcar that participate in fire, their behavior face to heat flux has... 

In this research, modelling of pyrolysis in small-scale and a method for calculation of kinetic parameters; activation energy, pre-exponential factor, and model function, have been presented. Calculation of activation energy and frequency factor without any assumption on model function heve been done by presented method. Because, incorrect assumption on model function can be cause to error in estimated values of activation energy and frequency factor.For a bench-scale sample, the heat transfer and mass conservations equations influence the pyrolysis process. In this research for the investigation of kinetic parameter effects, a simple pyrolysis model was presented to predicting the mass flux... 

Carbon nitride is a compound that has the proper energy gap (2.7 eV) for activities in the visible light. In this research, photocatalysts based on nanoporous Carbon nitride sheets was synthesized with three primary ingredient (urea, melamine and melamine hydrochloride) by pyrolysis method. Ag, Cu, Fe2O3 and Fe3O4 were added to the system to prevent the electron-hole recombination as well as increscent the photocatalytic activity. The chemical bonding state properties and microstructure of the synthesized photocatalysts were investigated by means of XRD, SEM, BET, FTIR, DRS and PL methods. In the first step of the research, the activity of prepared compounds was analyzed by visible light for... 

Fire is an undesirable phenomenon that causes human and financial losses. This in itself is a dangerous event that becomes even more dangerous in closed spaces. Car fires in underground car parks are no exception. In this research, the fire caused by burning flammable materials inside the car cabin located in a closed underground parking environment and the performance of sprinkler and water mist nozzles in controlling and extinguishing it have been investigated. Based on the broad foundations of various phenomena affecting this problem, including the separation of solid fuels under the influence of heat and oxygen, chemical reactions, radiant heat transfer and change of liquid phase to... 

The purpose of this study is the simulation of Printed Circuit Board’s thermal decomposition process based on the latest updated environmentally safe methods, to produce valuable materials. The method used is an efficient process for recycling printed circuits to prevent harmful environmental consequences of inadequate methods, and also to obtain a small amount of fuel for recycling. In this research, the pyrolysis process of printed circuits has been simulated using Aspen Plus software. In the simulation, a fluidized bed is used as a pyrolysis reactor and also a combination of two mechanisms is used to determine the kinetics and reactions in the reactor. The desired product in this process... 

During the last few years, the number of electric devices using lithium-ion batteries as a source of energy has increased drastically. The lifespan of these batteries is very short (2-3 years) and according to the statistics only 25% of which is recycled. However, considering the variety of materials used in these batteries, recycling them can be highly gainful. One of the technical challenges in the way of recycling Li-ion batteries is the presence of polyvinylidene fluoride (PVDF), that besides raising issues during recycling processes causes the production of toxic fluorine or hydrogen fluoride effluents. The second issue is the presence of metals with high oxidation states in these... 

In this study, pyrolysis features and corresponding kinetic behavior of non-metallic fractions of the paper-laminated phenol resin printed circuit boards (P-PCB) and fiberglass-reinforced epoxy resin printed circuit boards (E-PCB) were investigated by the use of simultaneous thermogravimetric analysis (TGA/DTG). The kinetic parameters of the P-PCB abs E-PCB during pyrolysis process were estimated from the experimental data by means of three iso-conversional kinetic models, including Friedman, Flynn-Wall-Ozawa (FWO), and Kissinger-Akahira-Sunose (KAS) methods. The activation energy range obtained for P-PCB and E-PCB utilizing the Friedman method was within 117–594.1 and 88.42-295.3 kJ.mol-1,... 

The COVID-19 pandemic has increased environmental risks due to widespread face mask use in production, consumption, and disposal. This study uses surgical single-use as a pyrolysis feedstock due to increased demand. This study investigates the conversion of valuable materials from waste through the recycling of surgical single-use masks in a fluidized bed. The first stage of this study focused on identifying and specifying the main components in the filter layers of disposable surgical masks, which were the compounds in the filter layers made of polypropylene. TGA curves investigated thermal behavior of disposable surgical mask layers, revealing pyrolysis feedstock can produce volatile...