Properties of fly ash-based spray-applied fire resistive materials

Spray-applied fire-resistive materials (SFRMs) are one of the most commonly used passive fire protection materials due to their low thermal conductivity, lightweight, cost-effectiveness, and ease of application. Gypsum and Portland cement are commonly used in SFRMs to bind lightweight fillers and fibres. Due to the wide application of SFRMs, their production consumes large amounts of natural and non-renewable resources and contributes significantly to greenhouse gas emissions. This paper investigates the feasibility of using industrial by-products (e.g., fly ash) and waste materials (e.g., waste glass) to manufacture SFRMs with the aim of reducing the environmental impact. Accordingly, three SFRMs with different densities were developed utilising fly ash blended cement (FAC) and expanded glass. The use of FAC significantly reduced the use of Portland cement by 81% and achieved a 28-day compressive strength of 33.8–46.3 MPa for the binder. The developed SFRMs had average densities of 345 kg/m3, 560 kg/m3, and 698 kg/m3 for low-, medium-, and high-density groups, respectively. The compressive strengths of the SFRMs ranged from 747 kPa to 888 kPa, 6188 kPa to 7314 kPa, and 2343 kPa to 3535 kPa for the corresponding three groups, respectively. Additionally, the bond strengths of the corresponding SFRMs are 14.4 kPa–19.3 kPa (low-density), 34 kPa–40.9 kPa (medium-density), and 51.5 kPa–85.1 kPa (high-density), respectively. All the tested SFRMs met the requirements for density, compressive strength, bond strength, and non-combustibility. The thermal properties of the developed SFRMs were comparable to those of commercially available cementitious-based SFRMs in the same density group. In addition, using FAC instead of Portland cement could reduce carbon emissions by 68.4% and save costs by 38.4% in the Australian context

Thermal and pyrolysis kinetics analysis of glass wool and XPS insulation materials used in high-rise buildings

This study investigates the kinetics data of glass wool (GW) and extruded polystyrene (XPS) insulation materials used in cladding systems using a systematic framework. The determination of appropriate kinetic properties, such as pre-exponential factors, activation energy and reaction orders, is crucial for accurately modelling the full-scale fire performance of insulation materials. The primary objective of this research is to extract thermal and kinetics data of XPS and GW insulation materials employed in high-rise buildings. To obtain these properties, thermogravimetric analysis (TGA) is conducted at four different heating rates: 5, 10, 15 and 20 K/min. The TGA results serve as the basis for determining the kinetic properties using a combination of model-free and model-based methods. The outcomes of this study are expected to be highly beneficial in defining the pyrolysis reaction steps and extracting kinetics data for fire modelling of such insulation materials. This information will enhance the understanding of the fire behaviour and performance of these materials during fire incidents, aiding in developing more accurate fire models and improving fire safety strategies for cladding systems in high-rise buildings

Testing of aluminium composite panels in a cone calorimeter : a new specimen preparation method

Fire testing data consistency and repeatability are essential for regulatory scrutiny, product development, and fire modelling of the lightweight cladding system. Lightweight composite claddings such as aluminium composite panels (ACPs) have been challenging to assess in terms of combustibility and flammability due to their sandwiched composite structures, which led to inconsistent data during bench-scale fire testing and fire risk assessment. This study aims to improve the test data consistency of reaction-to-fire properties such as time to ignition (tign), peak heat release rate (pHRR), time to peak heat release rate (tpHRR), total heat release (THR), which are the critical parameters for fire assessment and regulatory screening of the ACP claddings used in buildings. Therefore, a modified test approach is proposed in this study to facilitate the proper combustion process with the formation of a steady fuel gas/air mixture during the testing of cladding panel. The test data repeatability, standard deviation (SD) and relative standard deviation percentage (RSD%) of reaction-to-fire properties have been improved significantly with the modified test approach compared with the existing test approach

Photodynamic treatment of human breast and prostate cancer cells using rose bengal-encapsulated nanoparticles

Cancer, a prominent cause of death, presents treatment challenges, including high dosage requirements, drug resistance, poor tumour penetration and systemic toxicity in traditional chemotherapy. Photodynamic therapy, using photosensitizers like rose bengal (RB) with a green laser, shows promise against breast cancer cells in vitro. However, the hydrophilic RB struggles to efficiently penetrate the tumour site due to the unique clinical microenvironment, aggregating around rather than entering cancer cells. In this study, we have synthesized and characterized RB-encapsulated chitosan nanoparticles with a peak particle size of ~200 nm. These nanoparticles are readily nternalized by cells and, in combination with a green laser (λ = 532 nm) killed 94–98% of cultured human breast cancer cells (MCF-7) and prostate cancer cells (PC3) at a low dosage (25 μg/mL RB-nanoparticles, fluence ~126 J/cm2, and irradiance ~0.21 W/cm2). Furthermore, these nanoparticles are not toxic to cultured human normal breast cells (MCF10A), which opens an avenue for translational applications

Self-assembly of a rare high spin FeII/PdII tetradecanuclear cubic cage constructed via the metalloligand approach

Polynuclear heterobimetallic coordination cages in which different metal cations are con-nected within a ligand scaffold are known to adopt a variety of polyhedral architectures, many of which display interesting functions. Within the extensive array of coordination cages incorporating Fe(II) centres reported so far, the majority contain low-spin (LS) Fe(II), with high-spin (HS) Fe(II) being less common. Herein, we present the synthesis and characterisation of a new tetradecanu-clear heterobimetallic [Fe8 Pd6 L8 ](BF4 ]28 (1) cubic cage utilising the metalloligand approach. Use of the tripodal tris-imidazolimine derivative (2) permitted the formation of the tripodal HS Fe(II) metalloligand [FeL](BF4)2·CH3 OH (3) that was subsequently used to form the coordination cage 1. Magnetic and structural analyses gave insight into the manner in which the HS environment of the metalloligand was transferred into the cage architecture along with the structural changes that accompanied its occupancy of the eight corners of the discrete cubic structure

Diffusion of elements (Cr, Ni and C) in white cast iron bonded to steel cast composite alloys and the incorporation of WC particles

Recently a cast method for manufacturing alloy composites has been developed which offers improved flexibility with the manufacture of complex shapes. The composites produced to-date include white cast iron bonded to a steel substrate and are used primarily in the mining industry as wear parts, Fig. 1. Historically composite wear parts have been manufactured using vacuum brazing, hard-face weld deposits and laser cladding, which intrinsically have been limited to predominantly flat shapes. The cost of manufacture for these types of composites is relatively high due to the raw material processing required and surface preparation

Using a system called microValidator to monitor instrument health and calibration accuracy for forensic science

Accurate analysis results are always required for cases that have a legal consequence, or where a large scale industrial process is being monitored. This talk will cover the use of a system called “microValidator” which was developed to determine if the microscopy system is set up adequately to achieve consistent and reliable results when working with SEM/EDS, the forensic application automatic gunshot residue (GSR) particle analysis, or with the mining process control operation Mineral Liberation Analysis (MLA). The tool is used to automatically validate the performance of user’s systems and test the instrument operation and calibration (Instrument Health) for validation of SEM, EDS and the interface setup between SEM and EDS. This type of SEM/EDS validation procedure should be standard on all microscopes, especially when in-experienced operators are preparing legal reports, or controlling the direction of an automatic mineral processing system

X-ray mapping of wide gap brazed bi-metallic composites

Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013

Quantitative X-ray mapping, scatter diagrams and the generation of correction maps to obtain more information about your material

Quantitative X-ray mapping with silicon drift detectors and multi-EDS detector systems have become an invaluable analysis technique and one of the most useful methods of X-ray microanalysis today. The time to perform an X-ray map has reduced considerably with the ability to map minor and trace elements very accurately due to the larger detector area and higher count rate detectors. Live X-ray imaging can now be performed with a significant amount of data collected in a matter of minutes. A great deal of information can be obtained from X-ray maps. This includes; elemental relationship or scatter diagram creation, elemental ratio mapping, chemical phase mapping (CPM), and quantitative X-ray maps. In obtaining quantitative X-ray maps, we are able to easily generate atomic number (Z), absorption (A), fluorescence (F), theoretical back scatter coefficient ( _ ), and a quantitative total maps from each pixel in the image. This allows us to generate an image corresponding to each factor (for each element present). These images allow the user to predict and verify where they are likely to have problems in our images, and are especially helpful to look at possible interface artefacts. The post processing techniques to improve the quantitation of X-ray map data and the development of post processing techniques for improved characterisation are covered in this paper