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Extensive application of metal powder, particularly in nanosize could potentially lead to catastrophic dust explosion, due to their pyrophoric behavior, ignition sensitivity, and explosivity. To assess the appropriate measures preventing accidental metal dust explosions, it is vital to understand the physicochemical properties of the metal dust and their kinetic mechanism. In this work, explosion severity of aluminum and silver powder, which can be encountered in a passivated emitter and rear contact (PERC) solar cell, was explored in a 0.0012 m3 cylindrical vessel, by varying the particle size and powder concentration. The Pmax and dP/dtmax values of metal powder were demonstrated to increase with decreasing particle size. Additionally, it was found that the explosion severity of silver powder was lower than that of aluminum powder due to the more apparent agglomeration effect of silver particles. The reduction on the specific surface area attributed to the particles' agglomeration affects the oxidation reaction of the metal powder, as illustrated in the thermogravimetric (TG) curves. A sluggish oxidation reaction was demonstrated in the TG curve of silver powder, which is contradicted with aluminum powder. From the X-ray photoelectron spectroscopy (XPS) analysis, it is inferred that silver powder exhibited two reactions in which the dominant reaction produced Ag and the other reaction formed Ag2O. Meanwhile, for aluminum powder, explosion products only comprise Al2O3.

This paper provides an updated and comprehensive review on the catalytic upgrading of biomass-derived pyrolysis vapours over metal-modified HZSM-5 catalyst into bio-aromatic hydrocarbons. The catalytic upgrading of biomass pyrolysis vapours seems to be a promising technology in generating gasoline-type bio-aromatic hydrocarbons, i.e. benzene, toluene and xylene (BTX). Biomass-derived raw pyrolysis oil has high oxygenated compounds that deteriorate pyrolysis oil properties and limits its applications. Metal modification of hydrogen exchanged Zeolite Socony Mobil Five (HZSM-5) catalyst has gained attention in a biomass pyrolysis research area due to the beneficial effects on upgrading the oxygenated pyrolysis vapours into BTX-enriched pyrolysis oils. The influence of metals (alkali and alkaline earth metals, transition metals and rare earth metals) as bi-functional or multifunctional activity on HZSM-5 catalyst during pyrolysis has been addressed. The effect of reaction temperature, the type of metals, metal contents, the silica-to-alumina ratio of catalyst and the catalyst-to-biomass ratio are critically discussed for maximum production of monocyclic aromatic hydrocarbons during the upgrading of pyrolysis vapours. Finally, concluding remarks on metal-modified zeolite catalyst and future recommendation in upgrading biomass pyrolysis vapours are presented.

The understanding of biogas explosion characteristics is needed to describe the severity of the explosion. Biogas is a flammable gas and will explode when ignited. This study reports the experiment...

The objective of this research is to investigate the performance of Nickel-Cerium/HZSM-5 catalyst on pyrolysis of sugarcane bagasse and kinetic analysis via thermogravimetric analyzer. The sample is pyrolyzed from 30 to 700 °C at multiple heating rates (5, 10, 20, and 30 °C/min) in a nitrogen environment. The HZSM-5 was used as a support, while nickel and cerium were impregnated as promoters via incipient wetness impregnation method. For catalytic samples, the catalyst to biomass ratio was fixed at 1:1. The kinetic analysis of non-catalytic and catalytic pyrolysis was performed using the Flynn-Wall-Ozawa and Coats-Redfern methods. The catalytic pyrolysis has achieved higher activation energy (2.87 – 68.92 kJ/mol) over conversion than the non-catalytic pyrolysis (24.20 – 122.33 kJ/mol) using the Flynn-Wall-Ozawa method. The reaction mechanism of non-catalytic and catalytic pyrolysis follows power law (n=1) and chemical reaction (n=2) respectively via the Coats-Redfern method.

The production of pure silver nanoparticles (Ag-NPs) with unique properties remains a challenge even today. In the present study, the synthesis of silver nanoparticles (Ag-NPs) from natural pullulan (PL) was carried out using a radiation-induced method. It is known that pullulan is regarded as a microbial polysaccharide, which renders it suitable to act as a reducing and stabilizing agent during the production of Ag-NPs. Pullulan-assisted synthesis under gamma irradiation was successfully developed to obtain Ag-NPs, which was characterized by UV-Vis, XRD, TEM, and Zeta potential analysis. Pullulan was used as a stabilizer and template for the growth of silver nanoparticles, while gamma radiation was modified to be selective to reduce silver ions. The formation of Ag-NPs was confirmed using UV–Vis spectra by showing a surface plasmon resonance (SPR) band in the region of 410–420 nm. As observed by TEM images, it can be said that by increasing the radiation dose, the particle size decreases, resulting in a mean diameter of Ag-NPs ranging from 40.97 to 3.98 nm. The XRD analysis confirmed that silver metal structures with a face-centered cubic (FCC) crystal were present, while TEM images showed a spherical shape with smooth edges. XRD also demonstrated that increasing the dose of gamma radiation increases the crystallinity at a high purity of Ag-NPs. As examined by zeta potential, the synthesized Ag-NP/PL was negatively charged with high stability. Ag-NP/PL was then analysed for antimicrobial activity against Staphylococcus aureus, and it was found that it had high antibacterial activity. It is found that the adoption of radiation doses results in a stable and green reduction process for silver nanoparticles.

In the present work, a thermal treatment technique is applied for the synthesis of CexSn1−xO2 nanoparticles. Using this method has developed understanding of how lower and higher precursor values affect the morphology, structure, and optical properties of CexSn1−xO2 nanoparticles. CexSn1−xO2 nanoparticle synthesis involves a reaction between cerium and tin sources, namely, cerium nitrate hexahydrate and tin (II) chloride dihydrate, respectively, and the capping agent, polyvinylpyrrolidone (PVP). The findings indicate that lower x values yield smaller particle size with a higher energy band gap, while higher x values yield a larger particle size with a smaller energy band gap. Thus, products with lower x values may be suitable for antibacterial activity applications as smaller particles can diffuse through the cell wall faster, while products with higher x values may be suitable for solar cell energy applications as more electrons can be generated at larger particle sizes. The synthesized samples were profiled via a number of methods, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). As revealed by the XRD pattern analysis, the CexSn1−xO2 nanoparticles formed after calcination reflect the cubic fluorite structure and cassiterite-type tetragonal structure of CexSn1−xO2 nanoparticles. Meanwhile, using FT-IR analysis, Ce-O and Sn-O were confirmed as the primary bonds of ready CexSn1−xO2 nanoparticle samples, whilst TEM analysis highlighted that the average particle size was in the range 6−21 nm as the precursor concentration (Ce(NO3)3·6H2O) increased from 0.00 to 1.00. Moreover, the diffuse UV-visible reflectance spectra used to determine the optical band gap based on the Kubelka–Munk equation showed that an increase in x value has caused a decrease in the energy band gap and vice versa.

Biogas which consists of methane (CH4) and carbon dioxide (CO2) could explode when diluted to a certain degree with air in the presence of ignition source. The maximum explosion overpressure (Pmax), the maximum rate of pressure rise (dP/dt)max, flammability limits, and deflagration index are the most important explosion severities parameters to characterize the risk of explosion. In this research paper, the effect of equivalence ratio (ER) of biogas/air mixtures and the effect of CO2 concentrations presence in biogas were studied in a 20 L spherical vessel. The values of Pmax and (dP/dt)max of biogas/air mixtures were more severe at ER 1.2. At various CO2 content, Pmax and (dP/dt)max of biogas/air mixtures were the least affected at 45% vol/vol of CO2. On the other hand, deflagration index (KG) of biogas/air mixtures trend was the most severe at 35% vol/vol of CO2 content despite the lowest Pmax and (dP/dt)max at 45% vol/vol of CO2 content. The lowest values in Pmax and (dP/dt)max were due to the diffusivity properties of CH4 that had surpassed the CO2 suppression effect. Furthermore, the presence of CO2 in biogas/air mixtures had increased the upper flammability limit and lower flammability limit of biogas.

Sudden release of combustible/flammable materials at high pressure could result in the occurrence of a jet fire in the processing industry. Understanding the jet fire phenomenon and its mechanism could assist practitioners and researchers to predict the radiant energy transfer caused by the jet fire. Due to the dynamics of jet fire occurrence, the development of a semi-empirical model to predict thermal characteristics in different scenarios might provide huge advantages to the industry and safety practitioners as it is nonexpensive and a reliable prediction. There are four semi-empirical models for jet fire thermal radiation estimation that has been developed to date, namely, solid flame model (SFM), single-point source model (PSM), multipoint source model (MPSM), and line source model (LSM). It is the aim of this paper to explore each model applicability and approach to estimate the radiant heat flux based on the governing factors associated with the models, i.e., atmospheric transmissivity, flame length, lift-off length, flame shape, radiant heat fraction, total heat release, and receiver location. It is found that the applicability of each model and the derived parameters are largely contributed by the flame scale (small, medium, and large), flame orientation, flame length, and flame shape as well as the flame distance to the target receiver. From the discussion made, it can be suggested that for both near- and far-field measurement, the weighted MPSM is a reliable model that can be used for both vertical and horizontal orientations with some modification upon the consideration of buoyancy effect. On another note, LSM is able to provide a better prediction for linear trajectory of jet flame; however, the applicability is still limited for jet flame trajectory with buoyancy effects due to fewer data available and validation in various release conditions and scenarios.

Jet fires are a type of dangerous fire caused by the sudden release of flammable materials. In this work, propane was used as fuel and released through a 7.15mm and 9.8 mm circular nozzle with the exit velocities were set ranging between 27 and 65 m/s. The data of this study are compared against theoretical measurement and prediction using previously suggested correlation for projected flame length and flame extension length. It was determined, the projected flame length gives a good prediction by using theoretical measurement while for the prediction of flame extension length, an elliptical shape assumption was suitable to be used after impinging point for a horizontal buoyant jet fire.

Polysulfone (PSf) membranes are becoming more popular in wastewater treatment recently, mostly due to its stability in chemical, thermal and mechanical properties. PSf membranes are hydrophobic, causing difficulty of water permeation. Incorporating metal oxide nanoparticles improving the membrane hydrophilicity, thus increasing membrane permeation and rejection. In this study, copper oxide nanoparticle (CuO NPs) incorporated PSf membranes were fabricated under different evaporation times of 3s, 6s, 8s, and 9s to investigate on membrane morphology and performance. The membrane morphologies were characterized by using scanning electron microscope (SEM) while the membrane performance was determined through pure water flux (PWF) and bovine serum albumin (BSA) rejection. When characterized by SEM, all membranes showed an asymmetric structure with thin and dense at the top while the bottom layer was thick and porous. It was discovered that as the evaporation time increased, the formation of the finger-like structure became narrower while dense layer became thicker. When tested with PWF, membranes with higher evaporation times showed less permeability, decreasing from 139.74 Lm-2h-1 to 89.89 Lm-2h-1. In terms of BSA rejection, increased in evaporation time caused the rejection rate to increase from 87.79% to 92.15%. This study proved that evaporation time is one of important parameters that influences the membrane performance significantly.

A response surface methodology (RSM) was used to optimize the C6–C8 hydrocarbons in pyrolysis oil from catalytic upgrading of biomass-derived oxygenated pyrolysis vapour over the Ni-Ce/HZSM-5 catalyst via Box-Behnken design. The effect of operating factors such as pyrolysis reaction temperature, catalyst to biomass mass ratio, and nickel to cerium mass ratio on HZSM-5 was employed via in situ fixed bed reactor. The ANOVA results showed that the operating factors significantly affect the total contents of C6–C8 hydrocarbons in pyrolysis oil. The optimal conditions of factors within this study for the maximum contents of C6–C8 hydrocarbons in pyrolysis oil is attainable at a pyrolysis reaction temperature of 505 °C, catalyst to biomass mass ratio of 1.1:1.0, and nickel to cerium mass ratio of 3.14:2.86. The confirmation runs gave 8.83% and 8.86% of C6–C8 hydrocarbon contents (%) in pyrolysis oil compared with 8.90% of predicted value. The developed quadratic mathematical model is significant due to the P value

The main objective of the current work is to study the performance of the NiO and Ce2O3 loaded HZSM-5 catalyst on the catalytic upgrading of oxygenated pyrolysis vapours from sugarcane bagasse into high-quality pyrolysis oil consisting of C6–C8 hydrocarbons. The experiments were performed at five different pyrolysis reaction temperatures (400, 450, 500, 550 and 600 °C) via in situ fixed bed reactor. The HZSM-5 was used as a support, while nickel oxides and/or cerium oxides were impregnated via incipient wetness impregnation method. The catalyst-to-biomass mass ratio was kept constant at 1:1 for all investigated samples. The results revealed that the NiO-Ce2O3/HZSM-5 catalyst has synergistic effects on upgrading the oxygenated pyrolysis vapours into higher contents of C6–C8 hydrocarbons (8.82%) in pyrolysis oil at 500 °C compared with other investigated catalysts.

Dust explosion is considered as a serious threat for the industry that use or handle combustible materials as it may lead towards a significant economic loss in terms of damage to the facilities and suspension of activities, severe workplace injuries and fatalities. The rapid pressure developed during a dust explosion can be mitigated by venting. The present work explored the effects of venting on the explosion of different mixing weight ratios of aluminium and silver powder mixtures. The explosion characteristics of aluminium-silver mixtures were assessed in a 0.0012 m3 confined and vented cylindrical vessel. It was found that the application of 0.1 bar static burst pressure (Pstat) venting membrane gives one tenth reduction on explosion pressure and maximum rate of pressure rise for 70:30 and 50:50 mixing weight ratios of aluminium-silver mixtures explosion, respectively. This finding suggests that besides the venting application effect, the oxidation reaction of aluminium could be disrupted due to the presence of silver powder in the metal mixtures which results in lower heat transfer and reduction of the mass burning rate, hence, lessen flame speeds and explosion severity. However, the venting effectiveness is reduced when the Pstat increases. In order to assess the applicability of the dust explosion venting standard; NFPA 68 and EN 14491, the experimental results were compared with the calculated values according to the standards. The comparative results show that, both NFPA 68 and EN 14491 give underestimated values for explosion venting as compared with the experimental results.

The main objective of the present work is to investigate the influence of nickel to cerium ratio on Hydrogen exchanged Zeolite Socony Mobil-5 (HZSM-5) towards the catalytic upgrading of sugarcane bagasse derived oxygenated pyrolysis vapours into C6 – C8 hydrocarbons in pyrolysis oil via in-situ fixed bed reactor. The pyrolysis reaction temperature and catalyst to biomass mass ratio were kept constant at 500 °C and 1:1 respectively for all the investigated samples. The HZSM-5 was used as a support at 94 wt.%, while the balance 6 wt.% was impregnated with various weight of nickel and cerium as promoters based on the nickel to cerium ratios via incipient wetness impregnation method. The nickel to cerium ratios are as follows: 1:5 (NC1), 2:4 (NC2), 3:3 (NC3), 4:2 (NC4), and 5:1 (NC5). The results show that all the metal modified HZSM-5 catalysts had greatly suppressed the formation of coke contents (9.0–10.5 wt.%) compared to the HZSM-5 catalyst (NC0) (15.1 wt.%). The highest pyrolysis oil yield (60.5 wt.%) was achieved by NC2 catalyst. Among the tested nickel to cerium ratios, the NC3 catalyst has demonstrated to be the potential candidates in the catalytic upgrading of sugarcane bagasse derived oxygenated pyrolysis vapours into higher contents of C6 – C8 hydrocarbons in pyrolysis oil (8.82%).

The main objective of the current work is to investigate the influence of catalyst to biomass ratio (by weight%) on the catalytic upgrading of sugarcane bagasse derived pyrolysis vapours over cerium (Ce) loaded Hydrogen exchanged Zeolite Socony Mobil-5 (HZSM-5) catalyst via in-situ fixed bed reactor. The temperature of pyrolysis was kept at 500 °C for all investigated samples. The HZSM-5 catalyst was used as a support with 1 wt% of Ce as promoter loaded via incipient wetness impregnation method. The biomass sample was fixed at 2 g, while the catalyst mass loading was loaded according to the catalyst to biomass ratio which are 0.5:1.0, 1.0:1.0, 1.5:1.0, and 2.0:1.0. For comparison, the non-catalytic and biomass catalytic over HZSM-5 catalyst was also pyrolyzed at the same operating conditions. The results show that the yields of pyrolysis oil and coke were significantly influenced by the use of Ce/HZSM-5 catalyst at various catalyst to biomass ratio than the catalytic pyrolysis over HZSM-5, in which generate higher pyrolysis oil yield (58.0–68.0 wt%) and lower coke yield (2.9–4.1%). The increasing loading of mass in Ce/HZSM-5 catalyst has additional effect with respect to C6–C8 hydrocarbon contents in pyrolysis oil than the catalytic samples over the HZSM-5 catalyst. Among the tested catalyst to biomass ratio, the catalyst to biomass ratio of 1.5:1 has demonstrated to be the potential candidates in the catalytic upgrading of sugarcane bagasse derived oxygenated pyrolysis vapours into higher content of C6–C8 hydrocarbons (2.45%) in pyrolysis oil with lower coke yield (3.2%) over Ce/HZSM-5 catalyst. The bi-functional Ce/HZSM-5 catalyst was more effective in suppressing the coke formation in comparison to HZSM-5 catalyst at all investigated catalyst to biomass ratios and this was attributed to the synergistic effect of Ce on HZSM-5 support.

The main objective of the present work is to investigate the influence of catalyst to biomass ratio (C:B) on pyrolysis sugarcane bagasse over cerium loaded Hydrogen exchanged Zeolite Socony Mobil-5 (HZSM-5, Si/Al = 23) catalyst via in-situ fixed bed reactor. HZSM-5 catalyst was used as a support with 1 wt.% of Ce as promoter loaded via incipient wetness impregnation method. The pyrolysis oil (PO) yield and coke yield were significantly affected by the use of Ce/HZSM-5 at various C:B ratio than the none catalytic pyrolysis, in which generating low PO yields (50.0 wt.%). The increasing Ce/HZSM-5 loading has an additional effect with respect to PO and coke yields. Among the tested C:B ratio, a catalyst to biomass ratio of 1:1 has demonstrated to be potential candidates in the catalytic pyrolysis of SB into a higher yield of condensable pyrolysis oil with lower coke contents.

The main objective of the present work is to study the effect of molybdenum (Mo) loading amount on Hydrogen exchanged Zeolite Socony Mobil-5 (HZSM-5, Si/Al = 23) catalyst on pyrolysis of sugarcane bagasse via in-situ fixed bed reactor. HZSM-5 zeolite catalyst was used as a support with Mo as promoter modified at varying metal loading (0.5, 1.0 and 1.5 wt.%) via incipient wetness impregnation method. The pyrolysis oil (PO) yields and aromatic hydrocarbons (AHCs) yields were significantly affected by the use of all synthesized catalysts than the none catalytic pyrolysis, in which generating lower PO yields (11.7 wt.%) and AHCs yields (1.1 wt.%). The impregnation of Mo in the framework of HZSM-5 has an additional effect on the performance of the support HZSM-5 catalyst, with respect to PO and AHCs yields. Among all the catalysts tested, Mo(1 wt.%)/HZSM-5 catalyst has demonstrated to be potential candidates in the catalytic pyrolysis of sugarcane bagasse into a higher yield of ACHs in PO.

The main objective of the present work is to study the effect of Nickel-Cerium/Alumina multifunctional catalyst (Ni-Ce/Al2O3) mass loading on pyrolysis of coconut copra and rice husk via thermogravimetric analysis. The sample is pyrolyzed from 30 °C up to 700 °C at a constant heating rate of 10 °C/min in nitrogen environment flowing at 150 mL/min. The multifunctional catalyst (Ni-Ce/Al2O3) was prepared via incipient wet impregnation method. Pyrolysis feedstocks were prepared based on biomass to catalyst mass loading ratio. The TG-DTG curve shows that the presences of catalyst significantly affect the devolatilization rate of biomass. Among TGA-pyrolyzed coconut copra samples, the CC-3 (1:0.15) has achieved the highest mass loss (83.3%). For rice husk, the non-catalytic sample has attained the highest mass loss of volatile matter (48.7%). In addition, the kinetic characteristics of non-catalytic and catalytic pyrolysis of biomass were also studied and calculated by employing the Coats-Redfern integral method. The CC-1 has lower activation energy (53.10 kJ/mol) than that of catalytic sample particularly CC-3 (79.28 kJ/mol). The presence of a catalyst on rice husk is able to reduce the activation energy of non-catalytic rice husk sample from 49.78 to 45.24 kJ/mol.

Gas explosions in obstructed vessels have been investigated for many years. However, the flame acceleration mechanism of enriched-hydrogen fuels with diluents in the piping system has received little systematic study in the literature. This particular study aimed to analyse the flame front mechanism of hydrogen-diluents/air explosion inside the pipe by considering the influence of tee junction distance from the ignition points. The tests were performed using H2/diluents-air at different concentrations and ignition positions, in two different tee junction pipe configurations. From the results, the worst case of explosion severity was found in 95% H2–2.5% Ar–2.5% N2/air for all ignition positions. In general, if ignition happened at the tee junction, the overpressure and rate of pressure rise profiles showed almost a similar trend on both configurations. Similar trend was also observed for the flame flow characteristic analysis. Overall, it was clearly demonstrated that a shorter distance between ignition point and obstacles resulted in higher explosion severity.

The benefits of using hydrogen as a source of fuel seem to be limited due to a number of difficulties. To overcome the drawbacks of hydrogen, hydrocarbon-hydrogen fuel mixtures are the best substitutions. However, in literature, the flame acceleration of hydrogen-hydrocarbons/air mixtures in tee pipes has not yet been fully explored. Thus, the aim of this work is to report some new experimental data and provide an understanding of the explosion development in the geometry of tee pipes. In this study, premixed C2H4-H2/air, NG-H2/air and C3H8-H2/air mixtures with different ratios of 10:90, 30:70, 50:50, 70:30 and 90:10 were ignited at six ignition positions at two tee pipe configurations. Hydrocarbon fuels were considered as the primary gases. For the overall observation, it can be said that the flame reactivity of ethylene-hydrogen/air and NG-hydrogen/air was much higher. The kinetic reaction of these mixtures contributed to the overall explosion development. However, the dynamics of flame deployment in the tee junctions had a significant effect on the recorded maximum overpressure and flame speeds along the pipes. Moreover, the obtained data show that the lower distance of tee junction to ignition point caused a higher explosion severity in terms of the rate of pressure rise.

Based on recent developments, hydrogen-based combustion systems have received wide attention, mainly due to increasing awareness of enduring environmental pollutants and restricted access to fossil fuel usage. In the relevant literature, there are evidences of the possibilities on the partial or total replacement of hydrocarbon fuels with hydrogen in power plants and vehicle engines. However, some challenging issues particularly on hydrogen storage are remained to be resolved. This paper reviews and comments on addressing the effectiveness of hydrogen-enrichment on the engines and burners׳ performance includes the chemical kinetic analysis, the flame propagation structures and the effects of inhibitors on global burning velocity of hydrogen–hydrocarbon mixtures in different combustion bombs, chambers and vessels. It is recommended that future researches should aim towards the different application of hydrogen–hydrocarbon i.e. transportation and clean energy carrier.

Hydrogen is a promising fuel for the future. In recent years it has been successfully utilised in industries, particularly in refineries and petrochemicals. In previous studies, the effect of inhibitors on hydrogen explosion behaviour has been investigated in different systems, yet only scarce data are available. Therefore, experimental study is carried out to investigate the effects of argon, nitrogen and carbon dioxide on hydrogen/air explosion in a branched pipe configuration. The fuel/air mixtures were ignited at three different ignition positions, A, B and D. The results show that, when ignited at the furthest distance (position A), the tee junction area is most vulnerable to the critical pressure impact of gas explosion. However, no similar trend was observed at the other ignition positions. In addition, mixtures with the compositions 95% H2–2.5% Ar–2.5% N2/air, 95% H2–5% N2/air, H2/air and 95% H2–5% Ar/air showed higher risks due to the higher diffusivity ratio and the associated rate of pressure rise. This phenomenon is highlighted in the discussion part of this paper. The results show that mixtures with CO2 lead to lower severity than other compositions (∼50% reduction), as the average recorded maximum flame speed for this particular mixture was lower at all of the ignition points. This suggests that the effectiveness of the inhibitors should be in the order of Ar

This paper reports on the experimental and numerical analyses towards understanding the flame propagation in hydrogen and methane explosions, with the effect of pipe configurations. The experimental works were performed in a straight and 90-degree bend pipe with the length to diameter ratio, L/D is 51. FLACs code simulation was adopted to investigate the dynamic of flame behaviour in both pipe configurations. From the results, it was observed that the presence of 90-degree bend enhances the explosion severity by a factor of 1.03-3.58 as compared to that of the straight pipe. Based on the simulation analysis, the compression effect at the bending region and at the end of the pipe plays an important role to attenuate the burning rate, which results to the increase of the pressure wave. Furthermore, compression effect is the main mechanism for the flame to propagate and potentially lead to a catastrophic explosion.

Explosions caused by the rapid release of energy from the expansion of burnt gases, along with an associated pressure rise, in an enclosure can be mitigated by venting. Many empirical equations have been derived based on vented gas deflagration phenomena. In the present paper, four empirical equations for gas venting were reviewed, i.e., NFPA 68, the European Standard (EN 14994), Molkov et al. and Bradley and Mitcheson in order to assess their reliability and applicability for predicting the reduced explosion pressure (Pred) of propane-air, methane-air and hydrogen-air mixtures at three different chamber-scale volumes. The results showed that the NFPA 68 correlation is the most appropriate method for predicting Pred, while Bradley and Mitcheson gave values closer to those of experimental data for propane-air mixtures in medium and larger chambers, respectively. However, none of the predicted correlations was able to provide a reasonable prediction of Pred in a hydrogen-air explosion. In addition, these predicted correlations showed greater discrepancies in Pred values in the presence of vent area, ignition position and obstacles.

Biocomposite has been widely used as plastics replacement for its biodegradability. However, the water absorptivity defeats its purpose as food packaging. The water absorption analysis for pineapple peel fiber (PAPF) was done according to ASTM D570-98 and it has been proven that the water content increases to 7.2% with the 50% content of PAPF in the bio-composite (50% PAPF). For that matter, hydrophobic coating was synthesized and applied on PAPF based bio-composite. The bio-composite was produced using Low Density Polyethylene (LDPE), pineapple peel fibre (PAPF), Linear LDPE grafted maleic anhydride (LLDPE-g-MA) as compatibilizer and Refined, Bleached Deodorized Olein (RBDOL) as plasticizer. The coating was synthesized by using polydimethylsiloxane (PDMS) and decamethylcyclopentasiloxane as hydrophobic component, silica nano-particles as nanostructured particles and non-organic solvent and non-ionic surfactant p-octyl polyethylene glycol phenyl ether as surfactant. The emulsion was homogenized and after that sprayed onto the surface of PAPF bio-composite and dried in the oven at 50-60˚C for 24 hours. Through the 100µm magnification using field emission scanning electron microscope (FESEM), the hydrophobic coating was proven to conform the Cassie-Baxter hydrophobic property. C-O bond from the PAPF disintegrates after the production of bio-composite from the Attenuated Total Reflectance Fourier Transform Infrared (ATR FTIR) spectrometry transmittance. The application of the coating onto the surface of PAPF bio-composite gave the surface hydrophobic property where the contact angle changes from 82.27±2.66˚ which is hydrophilic to 122.63±2.17˚ which is hydrophobic. The bio-composite with the highest PAPF content will also exhibit self-cleaning ability which makes it suitable for the usage of hydrophobic food packaging material.

The International Atomic Energy Agency emphasizes on the safety assessment of fires involved by the crash of a large commercial aircraft into a nuclear power plant. In the guideline, it requires that a total load of aviation fuel that causes damage to exterior plants’ components should be included when performing the initial stages of the nuclear plant site evaluation process and over the entire lifetime of the plant operation. In this study, the effects of jet fuel and hydrogen-induced external explosion on a nuclear power plant was investigated and analyzed. A turbulence model based on Reynolds-averaged Navier-Stokes CFD solver, called FLACS, was used to determine the explosion parameters within the plant vicinity. The simulation results of key explosion parameters for butane explosion show a deflagrative overpressure of 0.27 bar and impulse load of 0.015 bar·s at some preselected position. An elevated local temperature of about 2030 K is recorded for this fuel. Hydrogen explosion causes a maximum overpressure of 0.37 bar, and a maximum positive pressure impulse load of 0.022 bar·s at the exterior walls of building structures. From the findings, it showed that building obstacles have a substantial influence on the evolution of fireball and overpressure propagation. The computed overpressure and impulsive loadings observed are capable of causing substantial structural damages and vulnerabilities. A significantly elevated flame temperature recorded would have a harmful effect on the safety function of structures, systems and components (SSCs) that are needed to execute reactor shutdown. The findings of this study may be used to revisit the safety evaluation of a nuclear power plant (NPP) site with regards to the risks and consequences associated with external explosion due to aircraft impact. It is also useful in designing the layout of the NPP and site placement of relevant items important to safety.

In this work, thermal degradation behavior of six local biomasses such as empty fruit bunch, rice husk, coconut pulp, saw dust, coconut shell, and sugarcane bagasse in Malaysia via pyrolysis was studied. The pyrolysis process was carried out from 25 to 700 °C under nitrogen atmosphere flowing at 150 ml/min via a thermogravimetric analyzer. The effect of biomass type was investigated on pyrolysis behavior. The particle size of biomass was in the range of 0.3 ≤ dp1 < 0.5 mm, whereas the heating rate was fixed at 80 °C/min. The thermogravimetric analysis (TGA) data were divided into three phases of degradation: moisture evolution, hemicellulose-cellulose degradation, and lignin degradation. The results showed that all biomass samples degraded between 25 and 170 °C in Phase I of moisture evolution. Among the biomass samples, coconut pulp achieved the highest mass loss (81.9%) in Phase II of hemicellulose-cellulose degradation. Lignin in all biomass samples gradually degraded from 450 to 700 °C in Phase III of lignin degradation. This study provides an important basis in understanding the intrinsic thermochemistry behind degradation reactions.

A new corrosion control system which is biological cathodic protection (CP) system was developed using the concept of microbial fuel cells (MFCs). Microorganisms available in domestic wastewater was utilised to generate electrons and supplied to the carbon steel pipe, and as consequence, protect the pipe from corrosion. There are various factors affect the performance of the system including the pH at the anode and cathode chamber. This study aims to analyse the optimum pH at anode and cathode. In this study, wastewater was used as the electrolyte and graphite rod as the electrode in the anode compartment while cathode compartment was filled with sand and carbon steel pipe acts as the cathode. Both compartments were connected by a plastic tubing and separated by the membrane. It was found that optimum pH at anolyte and catholyte were 8 and 6. The CP potential versus copper sulfate electrode (CSE) was -752 mV. It shows that the corrosion of carbon steel pipe was reduced since the native potential of the carbon steel pipe versus CSE was -560 mV.

In this study, the concept of Microbial Fuel Cells (MFCs) was applied in the biological cathodic protection (CP) system in order to protect steel pipe. There are various factors affect the performance of the system including the volume of the medium.The purposes of this study were to analyse and optimise the effect of volume ratio of wastewater to the sand on biological CP performance by using Taguchi method. The maximum performance of biological CP in this study was obtained at the largest volume ratio. The orthogonal array and the signal-to-noise ratio (S/N) were employed to study the effect of volume ratio on performance of biological CP. The CP potential vs. copper sulfate electrode (CSE) was -835 mV. It shows that the corrosion of carbon steel pipe was reduced since the native potential of the carbon steel pipe vs. CSE was -531 mV.

In this study, a series of tapioca starch-based low density polyethylene (LDPE) biofilms were prepared via extrusion process and further using blown film extrusion with various contents of starch. Various contents of glycerol and palm oil based olein as plasticizers, both ranging from 5 wt% to 20 wt% were added to blends. The starch-based LDPE blends were undergo the melt flow index analysis to study its processability before further process by film blowing extrusion. Both film blowing ability and melt indexes displayed the effect of both plasticizers in starch-based LDPE blends. Starch based LDPE biofilms with addition of 5 wt% palm oil based glycerin show large influence on the shear viscous properties of starch polymer melts compared to glycerol. Palm oil based glycerin would decrease the viscosity of starch polymer melt since it can decrease the polymer entanglement density and increase the ease of disentanglement.

This paper deals with the assessment of external explosion, resulting from accidental release of jet fuel from the large commercial airliner in the nuclear power plant (NPP). The study used three widely prediction methods such as Trinitrotoluene (TNT), multi energy (TNO) and Baker-strehow (BST) to determine the unconfined vapour cloud explosion (UVCE) overpressure within the distances of 100-1400 m from the first impact location. The containment building was taken as the reference position. The fatalities of persons and damage of structures was estimated using probit methodology. Analysis of the results shows that both reactor building and control-room will be highly damaged with risk consequences and probability, depending on the assumed position of the crash. The structures at the radial distance of 600 m may suffer major structural damage with probability ranging from 25 to 100%. The minor structural damage was observed throughout the bounds of the plant complex. The people working within 250 m radius may get affected with different fatality ranging from 28 to 100%. The findings of this study is valuable to evaluate the safety improvement needed on the NPP site and on the risk and consequences associated with the hydrocarbon fuel release/fires due to external hazards.

Normal 0 false false false EN-MY X-NONE X-NONE MicrosoftInternetExplorer4 The LDPE was blended with various contents of tapioca starch (10%, 20%, 30%, and 40%) with addition of compatibilizer, which is PE-g-MA and cooking oil as plasticizer. The blends were prepared by co-rotating twin screw extrusion process and characterized by melt flow index (MFI) analysis and tensile test. Tapioca starch based polyethylene biofilms were studied in term of biodegradability by fungi test. The increasing of starch content to LDPE blend was reduced the MFI values and tensile strength but in 30% and 40% of starch content in tensile strength is higher than control LDPE’s strength due to molecular orientation in sample. However, incorporation of PE-g-MA as compatibiliz increase the mechanical properties of starch based polyethylene blends due to the reaction between maleated PE and starch, thus improves adhesion and reduces slippage at matrix-filler interface.ers The increasing of TS also increase the water content in film sample, weight loss percentage in TGA, and percentage degradation of LDPE/TS blend film. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}