Displaying publications 1 - 20 of 92 in total

  1. Yek PNY, Liew RK, Osman MS, Lee CL, Chuah JH, Park YK, et al.
    J Environ Manage, 2019 Apr 15;236:245-253.
    PMID: 30735943 DOI: 10.1016/j.jenvman.2019.01.010
    Microwave-steam activation (MSA), an innovative pyrolysis approach combining the use of microwave heating and steam activation, was investigated for its potential production of high grade activated carbon (AC) from waste palm shell (WPS) for methylene blue removal. MSA was performed via pyrolytic carbonization of WPS to produce biochar as the first step followed by steam activation of the biochar using microwave heating to form AC. Optimum yield and adsorption efficiency of methylene blue were obtained using response surface methodology involving several key process parameters. The resulting AC was characterized for its porous characteristics, surface morphology, proximate analysis and elemental compositions. MSA provided a high activation temperature above 500 °C with short process time of 15 min and rapid heating rate (≤150 °C/min). The results from optimization showed that one gram of AC produced from steam activation under 10 min of microwave heating at 550 °C can remove up to 38.5 mg of methylene blue. The AC showed a high and uniform surface porosity consisting high fixed carbon (73 wt%), micropore and BET surface area of 763.1 and 570.8 m2/g respectively, hence suggesting the great potential of MSA as a promising approach to produce high grade adsorbent for dye removal.
    Matched MeSH terms: Steam*
  2. Zhou H, Saad JM, Li Q, Xu Y
    Waste Manag, 2020 Mar 01;104:42-50.
    PMID: 31962216 DOI: 10.1016/j.wasman.2020.01.017
    Recovery of chemicals and fuels from unrecyclable waste plastics at high temperatures (>800 °C) has received much research attention. Thermodynamic equilibrium calculation suggests that it is possible to perform the low-temperature steam reforming of polystyrene. In this study, we synthesized a Ni-Fe bimetallic catalyst for the low-temperature (500 °C) steam reforming of polystyrene. XRD characterization showed that Ni-Fe alloy was formed in the catalyst. Compared to conventional Ni catalysts, the Ni-Fe bimetallic catalysts can significantly increase the H2/CO ratio in the produced gas with high gas production yield. The online gas analysis revealed that H2, CO, and CO2 were formed in the same temperature range. H2 and CO were formed simultaneously through steam reforming reactions, and CO2 was formed through water-gas shift reaction. New morphologies of carbon deposition on the catalyst surface were found, suggesting that wax could be condensed on the catalyst surface at a low temperature.
    Matched MeSH terms: Steam*
  3. Wan Munirah, W.M., Tahir, A., Azmirul, A.
    The transformation method (TM) of fuzzy arithmetic is aimed at simulation and analysis of a system. The aim of this paper is to use fuzzy arithmetic based on the TM on a state space of a steam turbine system. The model is then used to identify the degree of influence of each parameter on the system. Simulation and analysis of the system are presented in this paper.
    Matched MeSH terms: Steam
  4. Valizadeh S, Lam SS, Ko CH, Lee SH, Farooq A, Yu YJ, et al.
    Bioresour Technol, 2021 Jan;320(Pt B):124313.
    PMID: 33197736 DOI: 10.1016/j.biortech.2020.124313
    Steam and air gasification with 5 wt% Ni/Al2O3 eggshell (Ni-EG) and homo (Ni-H) catalysts were performed for the first time to produce biohydrogen from food waste. The steam gasification produced comparably higher gas yield than air gasification. In non-catalytic experiments, steam gasification generated a higher volume percent of H2, whereas more CO, CO2, CH4, and C2-C4 were produced in air gasification. Ni-EG demonstrated higher potential to obtain H2-rich gases with a low C2-C4 content compared to that obtained by Ni-H, particularly in steam gasification at 800 °C, which produced gaseous products with 59.48 vol% H2. The long-term activity of both catalysts in steam gasification was evaluated, and Ni-EG exhibited higher stability than Ni-H. The ideal distribution of Ni species on the outer region of γ-Al2O3 pellets in Ni-EG resulted in higher activity, stability, and selectivity than Ni-H in both steam and air gasification.
    Matched MeSH terms: Steam*
  5. Yek PNY, Peng W, Wong CC, Liew RK, Ho YL, Wan Mahari WA, et al.
    J Hazard Mater, 2020 08 05;395:122636.
    PMID: 32298946 DOI: 10.1016/j.jhazmat.2020.122636
    We developed an innovative single-step pyrolysis approach that combines microwave heating and activation by CO2 or steam to transform orange peel waste (OPW) into microwave activated biochar (MAB). This involves carbonization and activation simultaneously under an inert environment. Using CO2 demonstrates dual functions in this approach, acting as purging gas to provide an inert environment for pyrolysis while activating highly porous MAB. This approach demonstrates rapid heating rate (15-120 °C/min), higher temperature (> 800 °C) and shorter process time (15 min) compared to conventional method using furnace (> 1 h). The MAB shows higher mass yield (31-44 wt %), high content of fixed carbon (58.6-61.2 wt %), Brunauer Emmett Teller (BET) surface area (158.5-305.1 m2/g), low ratio of H/C (0.3) and O/C (0.2). Activation with CO2 produces more micropores than using steam that generates more mesopores. Steam-activated MAB records a higher adsorption efficiency (136 mg/g) compared to CO2 activation (91 mg/g), achieving 89-93 % removal of Congo Red dye. The microwave pyrolysis coupled with steam or CO2 activation thereby represents a promising approach to transform fruit-peel waste to microwave-activated biochar that remove hazardous dye.
    Matched MeSH terms: Steam*
  6. Moogi S, Jang SH, Rhee GH, Ko CH, Choi YJ, Lee SH, et al.
    Chemosphere, 2022 Jan;287(Pt 2):132224.
    PMID: 34826918 DOI: 10.1016/j.chemosphere.2021.132224
    Food waste, a renewable resource, was converted to H2-rich gas via a catalytic steam gasification process. The effects of basic oxides (MgO, CaO, and SrO) with 10 wt% Ni/Al2O3 on the gasification properties of food waste were investigated using a U-shaped gasifier. All catalysts prepared by the precipitation method were analyzed by X-ray diffraction, H2-temperature-programmed reduction, NH3-temperature-programmed desorption, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The Ni/Al2O3 catalyst was reduced incompletely, and low nickel concentrations were detected on the surface of the alumina. The basic oxides minimized the number of acid sites and suppressed the formation of nickel-aluminate (NiAlxOy) phase in catalyst. In addition, the basic oxides shifted nickel-aluminate reduction reaction to lower temperatures. It resulted in enhancing nickel concentration on the catalyst surface and increasing gas yield and hydrogen selectivity. The low gas yield of the Ni/Al2O3 catalyst was attributed to the low nickel concentration on the surface. The maximum gas yield (66.0 wt%) and hydrogen selectivity (63.8 vol%) of the 10 wt% SrO- 10 wt% Ni/Al2O3 catalyst correlated with the highly dispersed nickel on the surface and low acidity. Furthermore, coke deposition during steam gasification varied with the surface acidity of the catalysts and less coke was formed on 10 wt% SrO- 10 wt% Ni/Al2O3 due to efficient tar cracking. This study showed that the steam gasification efficiency of the Ni/Al2O3 catalyst could be improved significantly by the addition of SrO.
    Matched MeSH terms: Steam*
  7. Valizadeh S, Khani Y, Yim H, Chai S, Chang D, Farooq A, et al.
    Environ Res, 2023 Feb 15;219:115070.
    PMID: 36549497 DOI: 10.1016/j.envres.2022.115070
    In this study, nickel-loaded perovskite oxides catalysts were synthesized via the impregnation of 10%Ni on XTiO3 (X = Ce, Sr, La, Ba, Ca, and Fe) supports and employed in the catalytic steam gasification of swine manure to produce H2-rich syngas for the first time. The synthesized catalysts were characterized using BET, H2-TPR, XRD, HR-TEM, and EDX analysis. Briefly, using perovskite supports resulted in the production of ultrafine catalyst nanoparticles with a uniform dispersion of Ni particles. According to the catalytic activity test, the gas yield showed the increment as 10% Ni/LaTiO3 < 10% Ni/FeTiO3 < 10% Ni/CeTiO3 < 10% Ni/BaTiO3 < 10% Ni/SrTiO3 < 10% Ni/CaTiO3. Meanwhile, zero coke formation was achieved due to the oxygen mobility of prepared catalysts. Also, the increase in the H2 production for the applied catalysts was in the sequence as 10% Ni/CeTiO3 < 10% Ni/FeTiO3 < 10% Ni/LaTiO3 < 10% Ni/BaTiO3 < 10% Ni/SrTiO3 < 10% Ni/CaTiO3. The maximum H2 selectivity (∼48 vol%) obtained by10% Ni/CaTiO3 was probably due to the synergistic effect of Ni and Ti on enhancing the water-gas shift reaction, and Ca on creating the maximum oxygen mobility compared to other alkaline earth metals doped at the A place of perovskite. Overall, this study provides a suitable solution for enhanced H2 production through steam gasification of swine manure along with suggesting the appropriate supports to prevent Ni deactivation by lowering coke formation at the same time.
    Matched MeSH terms: Steam*
  8. Nordin NI, Ariffin H, Andou Y, Hassan MA, Shirai Y, Nishida H, et al.
    Molecules, 2013 Jul 30;18(8):9132-46.
    PMID: 23903185 DOI: 10.3390/molecules18089132
    In this study, oil palm mesocarp fiber (OPMF) was treated with superheated steam (SHS) in order to modify its characteristics for biocomposite applications. Treatment was conducted at temperatures 190-230 °C for 1, 2 and 3 h. SHS-treated OPMF was evaluated for its chemical composition, thermal stability, morphology and crystallinity. OPMF treated at 230 °C exhibited lower hemicellulose content (9%) compared to the untreated OPMF (33%). Improved thermal stability of OPMF was found after the SHS treatment. Moreover, SEM and ICP analyses of SHS-treated OPMF showed that silica bodies were removed from OPMF after the SHS treatment. XRD results exhibited that OPMF crystallinity increased after SHS treatment, indicating tougher fiber properties. Hemicellulose removal makes the fiber surface more hydrophobic, whereby silica removal increases the surface roughness of the fiber. Overall, the results obtained herewith suggested that SHS is an effective treatment method for surface modification and subsequently improving the characteristics of the natural fiber. Most importantly, the use of novel, eco-friendly SHS may contribute to the green and sustainable treatment for surface modification of natural fiber.
    Matched MeSH terms: Steam*
  9. Kong, K.W., Emmy, H.K.I., Azizah, O., Amin, I., Tan, C.P.
    Lycopene and total phenolics of pink guava puree industry by-products (refiner, siever and decanter)
    were evaluated after steam blanching at selected temperatures and times. Lycopene content was in the order of decanter > siever > refiner (7.3, 6.3 and 1.5 mg/100 g, respectively), and the content of total phenolics was in the order of refiner > siever > decanter (4434.1, 2881.3 and 1529.3 mg GAE/100 g, respectively). Regression coefficients for temperatures (x1) and times (x2) from multiple linear regression models of siever and decanter showed significant (p
    Matched MeSH terms: Steam
  10. Nur Sakinah Abdul Aziz, Mazidah Tajjudin, Ramli Adnan
    Fuzzy Logic is a popular method to tune a PID controller. By using Fuzzy Logic, the PID is tuned automatically based on information of output error, which is better than other tuning rule methods. Fuzzy Logic Control will tune gains of PID controller by using a set of fuzzy rules designed specifically for that. However, specific transient requirements of the process output cannot be assigned to the controller. This research proposes a new method to overcome this problem by using a reference model. Step input from the reference model that contains the desired response information will be compared against the actual output. The reference model can be pre-selected by the user as desired. This study was simulated on a steam temperature process model while few sets of first-order model were used as reference. The results showed that the proposed Fuzzy PID controller with reference model provides better performance with perfect tracking during transient and steady-state.
    Matched MeSH terms: Steam
  11. Lim, S.F., Pah, P.Y.L., David Chua, S.N., Nicholas Kuan, H.T.
    Lemongrass leaves are often under-utilised and unexploited. In this study, lemongrass leaves were used to produce water soluble essential oil using a steam distillation system. Water steam was passed through the lemongrass leaves which were placed and supported on a grid above the water in a distiller. The steam distillation system was fabricated and optimised using Response Surface Methodology (RSM). The maximum oil yield with optimal relative citral content is obtained at 6.69 of plant-to-water ratio, 26.68 minutes of distillation time using air-dried lemongrass leaves left under the shade for two days. At the optimum conditions, the predicted oil yield was 0.6719% of lemongrass (C. citratus) oil which contains 71.79% of citral content.
    Matched MeSH terms: Steam
  12. Yeoh KH, Shafie SA, Al-Attab KA, Zainal ZA
    Bioresour Technol, 2018 Oct;265:365-371.
    PMID: 29925052 DOI: 10.1016/j.biortech.2018.06.024
    In this study, three different methods for high quality solid fuel production were tested and compared experimentally. Oil palm empty fruit bunches, mesocarp fibers, palm kernel shells and rubber seeds shells were treated using thermal (TC), hydrothermal (HTC) and vapothermal (VTC) carbonization. All thermochemical methods were accomplished by using a custom made batch-type reactor. Utilization of novel single reactor equipped with suspended internal container provided efficient operation since both steam generator and raw materials were placed inside the same reactor. Highest energy densification was achieved by VTC process followed by TC and HTC processes. The heating value enhancement in VTC and TC was achieved by the increase in fixed carbon content and reduction in volatile matter. The formation of the spherical components in HTC hydrochar which gave a sharp peak at 340 °C in the DTG curves was suggested as the reason that led to the increment in energy content.
    Matched MeSH terms: Steam
  13. Liu B, Yang L, Shi J, Zhang S, Yalçınkaya Ç, Alshalif AF
    Environ Pollut, 2023 Jan 15;317:120839.
    PMID: 36493937 DOI: 10.1016/j.envpol.2022.120839
    Stabilizing/solidificating municipal solid waste incineration fly ash (MIFA) with cement is a common strategy, and it is critical to study the high-value utilization of MIFA in ordinary Portland cement (OPC) components. With this aim, binary-binding-system mortar was produced by partially replacing OPC (∼50%) with MIFA, and the effects of different curing regimes (steam curing and carbonation curing) on the properties of the cement mortar were studied. The results showed that the setting time of the cement paste was shorten with the increase of MIFA content, and steam curing accelerated the hardening of the mixture. Although the incorporation of MIFA reduced the strength of the mortar, compared to conventional curing method, steam curing and carbonation curing increased the 3-d strength of the mortar. For high-volume MIFA mortars, the CO2-cured samples had the highest long-term strength and lowest permeability. The incorporation of MIFA increased the initial porosity of the mortar, thereby significantly increasing the carbonation degree and crystallinity of the reaction product - CaCO3. Steam curing also further narrowed the difference in the hydration degree between MIFA-modified sample and plain paste, which may be due to the enhanced hydraulic reactivity of MIFA at high temperatures. Although the incorporation of MIFA increased the porosity of the mortar, this waste-derived SCM refined the bulk pore structure and decreased the interconnected porosity. Additionally, the heavy metal leaching contents of MIFA-modified mortars were all below 1%, which meet the requirements of Chinese standards. Compared with standard curing, steam curing and carbonation curing made the early-age and long-term performance of MIFA-modified mortar better, which can promote the efficient application of MIFA in OPC products.
    Matched MeSH terms: Steam
  14. Ishida A, Toma T, Matsumoto Y, Yap SK, Maruyama Y
    Tree Physiol., 1996 Sep;16(9):779-85.
    PMID: 14871685
    Dryobalanops aromatica Gaertn. f. is a major tropical canopy species in lowland tropical rain forests in Peninsular Malaysia. Diurnal changes in net photosynthetic rate (A) and stomatal conductance to water vapor (g(s)) were measured in fully expanded young and old leaves in the uppermost canopy (35 m above ground). Maximum A was 12 and 10 micro mol m(-2) s(-1) in young and old leaves, respectively; however, because of large variation in A among leaves, mean maximum A in young and old leaves was only 6.6 and 5.5 micro mol m(-2) s(-1), respectively. Both g(s) and A declined in young leaves when T(leaf) exceeded 34 degrees C and leaf-to-air vapor pressure deficit (DeltaW) exceeded 0.025, whereas in old leaves, g(s) and A did not start to decline until T(leaf) and DeltaW exceeded 36 degrees C and 0.035, respectively. Under saturating light conditions, A was linearly related to g(s). The coefficient of variation (CV) for the difference between the CO(2) concentrations of ambient air and the leaf intercellular air space (C(a) - C(i)) was smaller than the CV for A or g(s), suggesting that maximum g(s) was mainly controlled by mesophyll assimilation (A/C(i)). Minimum C(i)/C(a) ratios were relatively high (0.72-0.73), indicating a small drought-induced stomatal limitation to A and non-conservative water use in the uppermost canopy leaves.
    Matched MeSH terms: Steam
  15. Lawal AA, Hassan MA, Ahmad Farid MA, Tengku Yasim-Anuar TA, Samsudin MH, Mohd Yusoff MZ, et al.
    Environ Pollut, 2021 Jan 15;269:116197.
    PMID: 33316496 DOI: 10.1016/j.envpol.2020.116197
    In order to meet the growing demand for adsorbents to treat wastewater effectively, there has been increased interest in using sustainable biomass feedstocks. In this present study, the dermal tissue of oil palm frond was pyrolyzed with superheated steam at 500 °C to produce nanoporous biochar as bioadsorbent. The effect of operating conditions was investigated to understand the adsorption mechanism and to enhance the adsorption of phenol and tannic acid. The biochar had a microporous structure with a Brunauer-Emmett-Teller surface area of 422 m2/g containing low polar groups. The adsorption capacity of 62.89 mg/g for phenol and 67.41 mg/g for tannic acid were obtained using 3 g/L biochar dosage after 8 h of treatment at solution pH of 6.5 and temperature of 45 °C. The Freundlich model had the best fit to the isotherm data of phenol (R2 of 0.9863), while the Langmuir model best elucidated the isotherm data of tannic acid (R2 of 0.9632). These indicated that the biochar-phenol interface was associated with a heterogeneous multilayer sorption mechanism, while the biochar-tannic acid interface had a nonspecific monolayer sorption mechanism. The residual concentration of 26.3 mg/L phenol and 23.1 mg/L tannic acid was achieved when treated from 260 mg/L three times consecutively with 1 g/L biochar dosage, compared to a reduction to 72.3 mg/L phenol and 69.9 mg/L tannic acid using 3 g/L biochar dosage in a single treatment. The biochar exhibited effective adsorption of phenol and tannic acid, making it possible to treat effluents that contain varieties of phenolic compounds.
    Matched MeSH terms: Steam
  16. Shaharuddin S, Husen R, Othman A
    J Food Sci Technol, 2021 Jun;58(6):2360-2367.
    PMID: 33967332 DOI: 10.1007/s13197-020-04748-0
    Baccaurea pubera is a blood red coloured fruit found exclusively in Borneo. This study was conducted to evaluate the effect of superheated steam treatment on its antioxidant properties and mineral content as well as to determine nutritional values of the fruit. The fruits were treated with superheated steam at 170 °C for 15 min prior to extraction and freeze drying. The results showed that, in comparison to the control, superheated steam treatment enhanced the total phenolic content by 147.8% (287.16 mg GAE/100 g vs. 115.87 mg GAE/100 g) and DPPH radical scavenging activity by 23.7% (66.94% vs. 54.13%). However, there were reductions, as compared to the control treatments, in total flavonoid content by 16.5% (8.29 mg QE/100 g vs. 9.93 mg QE/100 g), lycopene content by 28.6% (0.020 μg/100 g vs. 0.028 μg/100 g) and ferric reducing antioxidant power by 22.2% (844.41 mg TE/100 g vs. 1085.15 mg TE/100 g). The superheated steam treatment was also observed to reduce the mineral content of the fruit, from as little as 3.6% to as high as 52% depending upon the specific mineral.
    Matched MeSH terms: Steam
  17. Ayu RS, Khalina A, Harmaen AS, Zaman K, Mohd Nurrazi N, Isma T, et al.
    Sci Rep, 2020 01 24;10(1):1166.
    PMID: 31980742 DOI: 10.1038/s41598-020-58278-y
    In this study, it focused on empty fruit brunch (EFB) fibres reinforcement in polybutylene succinate (PBS) with modified tapioca starch by using hot press technique for the use of agricultural mulch film. Mechanical, morphological and thermal properties were studied. Mechanical analysis showed decreased in values of modulus strength for both tensile and flexural testing for fibres insertion. Higher EFB fibre contents in films resulted lower mechanical properties due to poor fibre wetting from insufficient matrix. This has also found evident in SEM micrograph, showing poor interfacial bonding. Water vapour permeability (WVP) shows as higher hydrophilic EFB fibre reinforcement contents, the rate of WVP also increase. Besides this, little or no significant changes on thermal properties for composite films. This is because high thermal stability PBS polymer show its superior thermal properties dominantly. Even though EFB fibres insertion into PBS/tapioca starch biocomposite films have found lower mechanical properties. It successfully reduced the cost of mulch film production without significant changes of thermal performances.
    Matched MeSH terms: Steam
  18. Suparta, W., Samah, A.A., Harper, A.R.
    ASM Science Journal, 2009;3(2):152-160.
    Katabatic winds dramatically affect the polar climate. Their activity depends on density of air and temperature in the source region. This paper presents for first time an analysis of the precipitable water vapour (PWV) variability and its relation to a katabatic event at Scott Base station, Antarctica. A significant effect in their characteristics toward calculation of a reliable user accuracy in GPS applications is addressed. Our investigations using the data between 21st and 30th of November 2002 showed that the PWV profile exhibited an irregular pattern with a maximum value of 7.38 mm (~ 6 mm on average), and was more strongly influenced by relative humidity than by wind speed activity. The dominant wind flow during this period was from the North-Northeast (blowing from the Ross Sea) with a median speed of 4.96 ms–1. The PWV was high when the temperature was between –15ºC and –11ºC. During the dates identified as a katabatic event between 21:30 UT of 28th November and 18:40 UT on 29th November, the wind blew from the Southeast-South direction (from the Ross Ice Shelf) with a maximum speed of 10.92 ms–1. The PWV increased ~1.4 mm (23%) from the mean value, indicating severe wind during this event which had pronounced effect on GPS observations.
    Matched MeSH terms: Steam
  19. Chia, S.L., Chong, G.H.
    Red pitaya (Hylocereus polyrhizus) peel is a rich source of fibre, antioxidant and betacyanin; however, it is discarded during processing, so it is able to cause environmental problems. In order to convert the fruit waste to potential by-product ingredients, drum drying is used as pre-treatment to create an ingredient which is shelf-stable. In this study, the effects of rotation speed and steam pressure of drums on the physico-chemical properties of pitaya peel that had undergone drum drying are investigated. Pitaya peel was dried in a laboratory scale double drum dryer at rotation speed of 1, 2, and 3 rpm at steam pressure of 1, 2, and 3 bar. The drum dried pitaya peel was then further analyzed based on percentage yield, moisture content, water activity, betacyanin retention and color change. Interaction of steam pressure and rotation speed gives significant effect (p < 0.05) on percentage yield, moisture content, water activity, betacyanin retention and Hunter L value, whereas it has no significant on Hunter a and b values. The best combination parameters (1 rpm and 2 bar) yield the highest betacyanin retention (80.21 mg/g of dry solid), acceptable moisture content (10.66% wet basis), water activity (aw = 0.42) and with 7.61% of yield.
    Matched MeSH terms: Steam
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