Good Fire Research Articles

Effect of toughening agent and flame‐retardant additives on the recycled polypropylene/oil palm empty fruit bunch laminated composites

AbstractThe increasing awareness of the environmental problems caused by the use of plastics has led to a demand for sustainable materials. The concept of turning waste into wealth has been considered in the study where the waste materials are value‐added into new composite materials that are recyclable, durable, and fire‐resistant. This effort aims to meet global environmental goals and the demand for high‐performance and sustainable building materials. The purpose of this current study is to develop laminated composites based on the combination of recycled plastic and oil palm empty fruit bunch (OPEFB). The addition of various loading of ammonium polyphosphate (APP) and 6 wt% of ethylene vinyl acetate (EVA) in the formulation was considered to enhance the performance of the composite laminates. The rPP and additives were compounded using a two‐roll mill. Then the rPP sheet and OPEFB were laminated using compression molding techniques. Results showed that rPP with addition of 30 wt% APP and 6 wt% EVA exhibited the highest thermal stability and the lowest melt flow index (MFI) value compared to other samples. Composites with 20 wt% APP and 6 wt% EVA showed 56% increase in flexural properties and 33% increase in impact strength compared to that of rPP/OPEFB composite sample without EVA. Addition of 30 wt% in recycled PP and OPEFB demonstrated self‐extinguished properties when exposed to fire compared to other samples. These findings indicated that rPP/OPEFB laminated composites with the addition of APP and EVA have a potential to be used in applications that require good strength and fire performance. The use of rPP/OPEFB composites with addition of APP and EVA has a potential to reduce virgin plastic consumption and agriculture material waste and establishing an environmentally friendly material for construction sector.Highlights Additives included in recycled PP enhance its thermal stability and reduce MFI. Recycled PP with OPEFB composite self‐extinguished at 30 wt% APP. The highest flexural strength is shown by composite laminates with 20 wt% APP and 6 wt% EVA. rPP/OPEFB laminates are ideal for building materials.

Seismic Performance Analysis of PEC Structures

Partially-Encased Composite Steel and Concrete Members (PEC members for short) consists of H-shaped cross-section of the main steel and concrete filling between the flange and the web, compared with the pure steel structure, the PEC structure has the advantages of high stiffness, high bearing capacity, good fire resistance and so on. The arrival of an earthquake may cause damage to building structures. The use of PEC structures can effectively improve their bearing capacity and seismic performance, and the method of post earthquake repair is relatively easier and more economical. In recent years, PEC components have been gradually popularized and applied in building structures.

P/N-containing SiO2 flame retardant particles formed by in-situ hydrolysis for significantly improve the flame retardancy and toughness of epoxy resins

To obtain flame retardants with more efficient and multidimensional flame retardant modes, this work formed P/N-containing silica flame retardants (PBPSi) by hydrolysis and used them in epoxy resins (EP) to give them good flame retardant properties. The hydrolyzed SiO2 flame retardant builds an integrated flame-retardant structure and a concentrated stress-bearing point, the EP has good fire resistant properties and toughness. Allowing the addition of 7-PBPSi/EPPBPSi to enable EP to achieve a UL-94 rating of V-0, and the impact strength of 5-PBPSi/EP reached 52.9 kJ/m2. In addition, PBPSi has good performance in inhibiting heat release and toxic gas release, and the PHRR and THR of 7-PBPSi/EP were reduced by 54.6 % and 24.6 %, respectively, compared with pure EP, the content of CO and CO2 also decreased. The analysis of the flame retardant mechanism indicated that PBPSi played a flame retardant role in the biphasic phase through the catalytic carbon formation in the condensed phase and the synergistic dilution of flammable gases and trapping of free radicals by P/N synergistic.

Simplified identification of fire spread risk in building clusters based on digital image processing technology

ABSTRACT Due to factors such as smoke, the non fire identification rate and fire identification accuracy in building fire identification are low, resulting in poor identification results. Therefore, a simplified identification method for building fire spread risk based on digital image processing technology is proposed. A fire spread model is constructed by considering both thermal radiation and thermal plumes, and based on this model, changes in smoke, temperature, and other factors during the occurrence of a fire are obtained. Using K-means to improve the dark channel defogging algorithm, the image after defogging is obtained, making the colour of the image more prominent and the feature information more abundant. Using the area threshold method to further extract the flame target contour in the defogged image, and determine whether the suspected flame area is a flame. Finally, four aspects of colour, sharp corner characteristics, area growth characteristics, and automatic estimation of propagation direction were identified to obtain simplified identification results for fire propagation risk. The experimental results show that the average non fire recognition rate of the proposed method reaches 95.8%, with good fire recognition accuracy and recognition effect, which verifies its feasibility.

Indigenous Fire Data Sovereignty: Applying Indigenous Data Sovereignty Principles to Fire Research

Indigenous Peoples have been stewarding lands with fire for ecosystem improvement since time immemorial. These stewardship practices are part and parcel of the ways in which Indigenous Peoples have long recorded and protected knowledge through our cultural transmission practices, such as oral histories. In short, our Peoples have always been data gatherers, and as this article presents, we are also fire data gatherers and stewards. Given the growing interest in fire research with Indigenous communities, there is an opportunity for guidance on data collection conducted equitably and responsibly with Indigenous Peoples. This Special Issue of Fire presents fire research approaches and data harvesting practices with Indigenous communities as we “Reimagine the Future of Living and Working with Fire”. Specifically, the article provides future-thinking practices that can achieve equitable, sustainable, and just outcomes with and for stakeholders and rightholders (the preferred term Indigenous Peoples use in partnerships with academics, agencies, and NGOs). This research takes from the following key documents to propose an “Indigenous fire data sovereignty” (IFDS) framework: (1) Articles declared in the United Nations Declaration on the Rights of Indigenous Peoples (UNDRIP) as identified by the author and specified in Indigenous-led and allied Indigenous fire research in Australia, Canada, and the U.S.; (2) recommendations specific to cultural fire policy and calls for research in the 2023 Wildland Fire Mitigation and Management Commission report; (3) research and data barriers and opportunities produced in the 2024 Good Fire II report; and threads from (4) the Indigenous Fire Management conceptual model. This paper brings together recommendations on Indigenous data sovereignty, which are principles developed by Indigenous researchers for the protection, dissemination, and stewardship of data collected from Tribal/Nation/Aboriginal/First Nations Indigenous communities. The proposed IFDS framework also identifies potential challenges to Indigenous fire data sovereignty. By doing so, the framework serves as an apparatus to deploy fire research and data harvesting practices that are culturally informed, responsible, and ethically demonstrated. The article concludes with specific calls to action for academics and researchers, allies, fire managers, policymakers, and Indigenous Peoples to consider in exercising Indigenous fire data sovereignty and applying Indigenous data sovereignty principles to fire research.

Self-assembled coatings with durable flame retardancy for EPS foam

Layer by layer (LBL) self-assembly coatings upon expandable polystyrene (EPS) surface play an important role in improving its flame retardancy. However, a large number of layers is needed to achieve a satisfied fire performance, and the coatings are difficult to adhere on the inert EPS surface, resulting in the poor durability. In this work, the surface of EPS was activated by ultraviolet ozone (UVO) with the appearance of oxygen contained groups, then a LBL coating with only two bilayers (branched polyethyleneimine (BPEI)-kaolinite (kaol)-BPEI-diethylene triamine penta (methylene phosphonic acid)) was covalently connected on the EPS surface. Compared with neat EPS, the obtained E-K5D30 sample increased the value of limiting oxygen index (LOI) from 18.8 % to 37.7 %, improved the ignition time from 59 s to 95 s, reduced the peak heat release rate (pHRR) value from 282.0 kW/m2 to 220.9 kW/m2, and enhanced the char residues from 6.3 % to 32.3 % after the combustion. Moreover, an ultraviolet (UV) curing layer with P/N elements was prepared upon E-K5D30 sample to maximize the flame retardant durability. A novel amino-intercalated kaol was used to play a smoke suppression role. The results showed that E-K*5D30-P8N3 sample further increased the LOI to 39.2 %. Even after 12 h washing, the E-K*5D30-P8N3 sample exhibited a slight LOI reduction to 37.8 %, and fire performance index (FPI) value of 0.405 m2·s/kW, showing the successful construction of coatings with good fire safety and flame retardant durability.

From waste to resource: Exploring the recyclability and performance of gypsum-graphene nanofiber composites

Gypsum is a widely used building material with a variety of benefits, including good fire resistance, sound insulation, and environmental friendliness. However, gypsum disposal is commonly associated with significant environmental risks, including unhealthy gas emissions and land degradation. Gypsum recycling can help to reduce these impacts, but it can also lead to a decrease in the performance of the recycled gypsum products. This study investigated the effects of graphene nanofibers (GNFs) on the recyclability and properties of gypsum plasters. The results showed that test samples containing 1 % of GNFs exhibited improved mechanical response, with flexural and compressive strength exceeding those of neat gypsum by 30 % and 60 % respectively. This improvement is attributed to the retained functional properties of GNFs during the recycling process. Recycled gypsum pastes containing GNFs presented a more uniform and denser matrix with longer crystals, enhanced bonding, and reduced porosity. These findings suggest that GNFs can be used to facilitate the recycling of gypsum waste and to produce recycled gypsum components with improved properties. Overall, this study demonstrates the potential of GNFs to improve the sustainability and performance of recycled gypsum plasters.

Convert bamboo into high-performance, long-time durability, and fire-retardant with hyperbranched polyethylene glycol and boron

Despite renewable bamboo globally available and has been applied in industry, the bamboo modification still absents for achieving long-term anti-mildew, stability and desirable toughness, owing to its inherent hierarchical porous structures, that cannot fully insert and retain ideal drugs/polymers. Hence, a hyperbranched polymer (HPB) with polyether as backbone and phenylboronic acid as binding groups via epoxy ring-opening reactions with amino was designed, and subsequently in situ synthesized in the multi-scaled cellular structures in bamboo. It was demonstrated that the hyperbranched polyether chains filled and swollen the hierarchical bamboo cell walls, which could efficiently replace the inner hydroscopic water in bamboo and greatly improved the bamboo stability, resulted in the wet swelling and dry shrinkage rates reduced by 20.3 % and 14.8 %, respectively. Both the side groups of phenylboronic acid and epoxy on HPB outer layers could generate covalent bonding with bamboo cell walls, which twisted the easy-losing facts of boron and gained a 60.6 % retention rate, surpassed most reported modified bamboo literatures and conferred bamboo with good fire resistance and long-time anti-mildew performance. Importantly, with the cavitation effect of HPB to help stress transmission, the modified bamboo had not expensed bamboo strength, instead of reaching satisfied bending strength and toughness at 154.1 MPa of flexure strength and 10.8 % of bending strain, respectively. That expand the industrial application of bamboo.

Ultra-stable foam enabled by nano silica engineering for foam concrete improvement

Foam concrete is increasingly applied in construction due to its lightweight, good thermal insulation and fire resistance, and environmental sustainability, while its low strength limits its further popularization and applications. To enhance the stability and performance of foam concrete, amphiphilic nano silica (ANS) was employed in this study to modify the sodium dodecyl sulphate (SDS) based foaming agent. Then, the designed foam was utilized to fabricate foam concrete, of which the micro/macro performance was analysed in detail. The results showed that ANS-modified foam exhibited superior stability with a thicker foam wall thickness, contributing to the enhancement of foam stability within the cement matrix. The foam concrete with ANS exhibited higher strength compared to the control groups. The analysis of pore structures revealed that the ANS modification led to a more rounded and homogeneous pore configuration, characterized by an increased proportion of small and medium-sized pores and a decreased average pore size. The increase in pore roundness was accompanied by a reduction in the number of sharp edges of the pores and therefore a reduction in the stress concentration factor, while the moderately sized pore also was more conducive to increasing strength due to its lower stress concentration. As a result, the strength of the concrete is significantly increased. These findings demonstrate the potential of ANS as an effective foam stabilizer for foam concrete production, leading to enhanced foam stability and improved mechanical properties of concrete.

Comparison between Waterproofing Sheets Membrane and Polyurea Waterproofing Coating Methods

This research aims to compare between Waterproofing Sheets Membrane and Polyurea Waterproofing Coating Methods, and know the waterproofing methods applying time, cost, weight, materials durability, and the waterproofing methods materials fire resistance properties. The research used qualitative analysis techniques to compare the two waterproofing methods objectively, Through lab testing, researchers found that: the polyurea waterproofing coating method usually takes between 1 to 2 working days to apply while the traditional sheet membrane waterproofing method takes between 5 to 7 working days applying time, and the polyurea waterproofing coating method can be more expensive than the traditional waterproofing sheet membranes method. Applying polyurea requires specialized equipment and trained personnel for proper handling and application, Both methods' materials weight are considered relatively light but the polyurea coating method materials are lighter, the polyurea waterproofing coating system lasts up to 30 years. Rather than the traditional system which durability is up to 20 years, the polyurea waterproofing coating system is considered a good fire resistance system rather than traditional sheet membrane system. It is recommended to clean and clear the surface before the commence of the waterproofing process. and the surface needs to be tested for at least 3 full days to confirm that the waterproofing system was applied successfully and without missing any openings.

Behaviour of glass and sisal incorporated gypsum based composite panels under axial compression–experimental and numerical study

Gypsum based composite (GBC) Wall panels are being used in precast concrete industry as the panels are low cost, energy consumption, good habitability, and good fire resistance. This paper presents the studies related to gypsum based composite panels incorporated with glass and sisal fibers. The main objective of the research is to investigate the capacity of gypsum based composite wall panel subjected to axial compression with and without eccentricity. The panels were loaded in axial compression with and without eccentricity. Gypsum, white cement, fibres (glass fibers or sisal fibers) are used to prepare composite panels of size 1000 (length) × 500 (width) × 125 (thickness) mm. Total four panels (two with glass fibers and two with sisal fibers) were tested under axial compression (two panels without eccentricity and two panels with eccentricity) were tested under load control. From the tests, it was observed that the eccentric load application on the panels is very significant compared to normal load application. Significant decrease in the ultimate load is observed for the case of panels subjected to eccentric loading. Nonlinear finite element analysis for the fibre incorporated (E-glass and sisal) gypsum based composite panels under axial compression has been carried out by using the general purpose finite element software.

Why engaged critical urban research must place scholar policy activism at its core

I welcome and endorse Loretta Lees' call for a reconstituted critical urban studies tradition predicated upon polyvocal, intersectoral and co-produced research, dialogues and dialoguing and concurrent and compounding critical intelligences. In this short commentary, I make the case for placing scholar policy activism at the heart of such a tradition. I explore how and why critical urban research has come to view executive power as its arch nemesis. I argue that continued estrangement and jousting between the architects of radical praxis and those of policy practice is indefensible. I scope the contours of a new generation of policy engaged critical scholarship. We can no longer in good conscience fire missiles from inside the ivory tower and outside of the governing tent in the hope that better cities will result. If we are to be serious about ‘shaking up the city’, we will need to work with and on sources of power – to immerse ourselves in the epistemic communities which enjoy dominion over policy registers – and recalibrate the urban ‘partition of the sensible’.

INFLUENCE OF THE ADDITION OF LIME ON A MATRIX EARTH REINFORCED WITH COCONUT FIBER

The present research is based on improving the stability, resistance to moisture degradation and fire resistance of molded soil blocks for use in housing construction. The main objective was to include fibers obtained from the shell of the coconut fruit and slaked lime. The methodology includes a prior characterization of the materials using the Eades and Grim method (ASTM D6276), density test, Atterberg limits and granulometric study; and then combine the fiber and lime into a local soil matrix. It is then subjected to water absorption and erosion tests, and is also subjected to direct fire. The results reveal that the additions of 0.5% fiber and 7% lime showed changes in the weight of the blocks, at the same time improvements in the resistance to water absorption and also good fire resistance. Finally, the results are compared with the scientific literature consulted, in order to correlate them with each other.

Effect of phytate doped cobalt and copper ion modified carbon nanotubes on flame retardancy and ceramic properties of silicone rubber

AbstractSilicone rubber (SR) has excellent properties, such as high and low temperature resistance and weather resistance. However, the flame retardancy of SR is rather poor, which severely limits the range of application of SR. Therefore, it is necessary to make certain modifications in order to improve its flame retardancy. In this study, wollastonite, low‐melting glass powder, and phytate‐modified carbon nanotubes (CPCC) were added to SR to prepare ceramizable silicone rubber (CSR) composites with good fire safety performance. The effect of CPCC on the flame retardancy and ceramization properties of CSR materials was investigated. The results showed that, with the addition of 3 phr of CPCC, the limiting oxygen index of the CSR composite material reached 33.8%, which was 26.1% higher than that of pure SR, and its UL‐94 grade reached V‐0 grade. The results of the cone calorimeter test showed that the total heat release of the CSR composite with three parts CPCC was reduced by 26.6%, and the peak heat release rate reduced by 13.1%. In addition, after the CSR6 composite was calcined at 1000°C for 1 h, the ceramic body formed by the composite had good supporting properties, and its bending strength was as high as 6.17 MPa.

Post-Fire Behavior of Modified SIFCON One-Way Plates with Waste Tire Rubber under Flexural Load: Experimental and Numerical Study

In this research, an experimental and numerical investigation was conducted to study the flexural behavior of modified slurry-infiltrated fiber concrete slurry-infiltrated fibrous concrete (SIFCON) one-way plates after being subjected to a high temperature. The first part is an experimental work to ensure that the model developed is adequate, while the second part is a 3D finite element modeling of the SIFCON plates with the program ABAQUS using a sequentially coupled thermal displacement analysis. The experimental program included testing eight modified SIFCON plates containing waste powder rubber as a partial substitute for natural sand (0%, 5%, 10%, and 15%). All adopted specimens had identical dimensions (1,000 mm length, 300 mm width, and 50 mm thickness). Four specimens were exposed to fire for 2 hr at a constant temperature of 600°C, after which they were rapidly cooled by spraying them with water. Test results showed that increasing the powder rubber content of burned and unburned modified SIFCON specimens decreased the failure load and increased the specimens’ ductility factor, as well as the ultimate and service deflections. During the test, the failure of SIFCON was observed to be gradual, and the plates remained in contact even after the ultimate load was attained, whereas the failure of the reference mix (without wasted rubber) was observed to be more rapid than that of other SIFCON mixtures. For the flexural test, it gives desirable strength and good fire resistance. This study provides guidance for the study of SIFCON with waste rubber. Overall, the percentage of error between the experimental and numerical results for the load capacity and midspan displacement was about 5.05% and 8.65%, respectively.

4-Hydroxybenzenesulfonic acid triggers rapid preparation of phenolic aerogel composites by ambient pressure drying

Phenolic aerogel composites, as an excellent thermal insulation material, have been used in aerospace to resist extreme working conditions of severe heating and intense mechanical stress. However, the high cost and lengthy preparation process seriously restricts their more extensive application. Herein, a novel strategy for rapid preparation of aerogel composites by ambient pressure drying is enabled by copolymerization with 4-hydroxybenzenesulfonic acid. That is, the reactive 4-hydroxybenzenesulfonic acid can serve as the acid catalyst to accelerate both the protonation step and the gelation step during the preparation process of phenolic aerogel. After copolymerization with 4-hydroxybenzenesulfonic acid, these sulfonic acid groups significantly accelerate the protonation of benzoxazine intermediates, leading to more carbocation formation. The activation energy of curing reaction is significant decreased from 300 kJ∙mol−1 to 90 kJ∙mol−1. Thus, 4-hydroxybenzenesulfonic acid containing phenol formaldehyde resin (PFS) aerogel precursors exhibit much faster gelation reaction (within 4 h) than phenol formaldehyde resin (PF) aerogel precursor (12 h), which further facilitates the preparation of phenolic aerogel composites with needled quartz fiber felt by ambient pressure drying. Importantly, the PFS aerogel composites exhibit excellent thermal insulation performance under low heat flux and good fire safety under high heat flux. Rapid gelation of PFS triggered by 4-hydroxybenzenesulfonic acid provides a new approach to develop phenolic aerogel composites with low energy consumption, low cost and short preparation cycle.

Experimental and numerical study on seismic behavior of special shaped steel truss and concrete composite shear wall

A steel truss-concrete composite (STCC) shear wall is fabricated by replacing the reinforcement of the shear wall by steel truss, which has high bearing capacity, good fire resistance, good seismic performance, and an easy construction. In order to investigate the seismic performance of special shaped composite shear wall, a quasi-static test was carried out on four T-shaped and two L-shaped composite shear walls. The results showed that the change of diagonal bracing form from strip steel to channel steel can improve the ductility and energy dissipation capacity of the shear wall and delay the strength degradation. Increasing the thickness of steel vertical supports can effectively improve the initial stiffness, while decreasing the thickness of diagonal braces will reduce the bearing capacity of the wall. The strength and stiffness of shear walls loaded along the web in the positive direction (flange in tension) is high, but the ductility is relatively poor when compared with walls loaded in the negative direction (flange in compression). Numerical models were established by ABAQUS, in which the steel hysteretic constitutive model was adjusted to simulate the influence of bond-slip effect. The influence of shear span ratio, axial load ratio, steel ratio of vertical support, volumetric ratio of diagonal brace, tilt angle of diagonal brace and horizontal force direction on the seismic performance of T & L shaped composite shear walls were analyzed. Finally, a design method was proposed, and the calculated results by the design method were in good agreement with the test.

Fire research of joint between special-shaped CFST column and U-shaped composite beam

The steel-concrete composite joint plays an important role in the building structure of transmitting load and maintaining structural stability, and the research on fire performance of composite joints is significant. The special-shaped concrete-filled steel tube (SCFST) column and U-shaped steel-concrete composite beam (USCB) have good fire resistance which is proved by authors' previous fire tests. Therefore, the fire performance of the joint between SCFST column and USCB, the temperature distribution, failure mode, fire resistance, and internal force distribution of the joint under fire are investigated based on the fire tests results of column and beam component. The results showed that the temperature of the joint zone is lower than that of the non-joint zone, which ensured that the strength and stiffness of the joint zone are higher than that of the non-joint zone (beam and column). Then the two failure modes including beam failure and column failure occurred in the composite joint in fire conditions. Furthermore, the internal force analysis indicated that internal force redistribution happens during the elevated temperature. The parameter analysis expressed that fire resistance decreases with the increase of load ratio and the beam-column moment ratio and increases with the increase of the beam-column stiffness ratio and the fire protection layer thickness. Finally, the high-temperature calculation formula for the bearing capacity of beam-column joint was proposed.

Possibilities of Using Geopolymers in Welding Processes and Protection against High Temperatures

Geopolymer materials have long been known for their competitive properties against traditional construction materials. Their special features include high resistance to elevated temperatures and good fire resistance. They are typically used as insulating materials at temperatures not exceeding 100 °C (because they can achieve a thermal conductivity coefficient of 0.060 W/m × K or less under these conditions). Still, they can also be used as thermal insulation at temperatures exceeding 1000 °C. One technology that uses very high temperatures is metal welding technology, where temperatures often exceed as many as 3000 °C. Geopolymers, due to their properties, can also be an interesting new alternative in various welding applications. This paper presents the preliminary results of pot-proofing the resistance of geopolymers to temperatures exceeding 3000 °C. Test results of a foamed geopolymer insulating a steel substrate are presented, and a geopolymer mold for thermite rail welding was made and realistically tested. The results confirmed the feasibility of using cast geopolymer molds for thermite welding of railroad rails. The geopolymer material performed well during the test and no cracks or other damage occurred. The following article presents the potential of using geopolymer materials for welding applications.

Using the methods to calculate parameters of drilling and +blasting operations for emulsion explosives

Mathematical modelling of rock mass breaking using blasting has been applied to obtain formulas for the calculation of crush zone radii, intensive fragmentation, and crack formation around the charging cavity in the structure, diameter of the charging cavity, diameter of the charge itself, detonation characteristics of an explosive, boundaries of the rock strength, rock mass jointing, and mineral compression under the effect of rock pressure. The methods have been developed to calculate parameters of drilling and blasting operations (DBOs) while driving the mine workings based upon the idea of the arrangement of blastholes in terms of areas they occupy in a fore-breast as well as upon their location relative to break-off outline. Stage one of the methods involves calculating and designing burn cuts where a distance between blastholes is determined with the help of a fragmentation zone radius. Stage two means calculation of both specific and total explosion consumption per borehole bottom, line of least resistance (LLR) for a borehole in terms of intensive fragmentation, areas of borehole groups, borehole number, analytical and actual distance between boreholes, actual charge amount per borehole, and actual specific and the total explosive (E) consumption per borehole bottom. The methods have been tested in the operating ore mine while driving a mine working. Emulsion explosive (EE) Ukrayinit-PP-2 (Україніт-ПП-2) has been applied. The developed methods have been used to calculate DBOs parameters for the explosive. Trial blasts demonstrated the good firing of a borehole bottom and uniform ore fragmentation; a high coefficient of borehole use has been supported.