Displaying publications 1 - 20 of 840 in total

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  1. Palaniandy, Samayamutthirian, Khairun Azizi Mohd Azizli, Hashim Hussin, Syed Fuad Saiyid Hashim
    MyJurnal
    Mechanical activation of quartz was carried out in jet mill at various specific kinetic energy level and classifier speed. The characterization of the particle size, crystallite size, amorphism rate and lattice strain was conducted on the feed and mechanically activated particles. The area under the prominent quartz peak was used to calculate the amorphism rate of the mechanically activated particles. Scherer equation was used to determine the crystallite size of the feed and mechanically activated particles. Mean particle size less than 5μm was obtained when the specific kinetic energy is ranging between 500 kWh/ton and 1000 kWh/ton. Amorphism of the mechanically activated particles up to 18% was observed at 500 kWh/ton. The crystallite size and lattice strain is influence by the intensity of the specific kinetic energy and classifier speed. The reduction in the crystallite size up to 39% was observed where the minimum crystallite is 23nm. The lattice strain is ranging from 0.024 to 0.038 respective to the specific kinetic energy and classifier speed.
    Matched MeSH terms: Kinetics
  2. Ali A, Sharma RK, Ganesan P, Akib S
    ScientificWorldJournal, 2014;2014:412136.
    PMID: 25136666 DOI: 10.1155/2014/412136
    A numerical investigation of incompressible and transient flow around circular pipe has been carried out at different five gap phases. Flow equations such as Navier-Stokes and continuity equations have been solved using finite volume method. Unsteady horizontal velocity and kinetic energy square root profiles are plotted using different turbulence models and their sensitivity is checked against published experimental results. Flow parameters such as horizontal velocity under pipe, pressure coefficient, wall shear stress, drag coefficient, and lift coefficient are studied and presented graphically to investigate the flow behavior around an immovable pipe and scoured bed.
    Matched MeSH terms: Kinetics
  3. Karamba KI, Ahmad SA, Zulkharnain A, Yasid NA, Ibrahim S, Shukor MY
    3 Biotech, 2018 Jan;8(1):11.
    PMID: 29259886 DOI: 10.1007/s13205-017-1025-x
    The evaluation of degradation and growth kinetics of Serratia marcescens strain AQ07 was carried out using three half-order models at all the initial concentrations of cyanide with the values of regression exceeding 0.97. The presence of varying cyanide concentrations reveals that the growth and degradation of bacteria were affected by the increase in cyanide concentration with a total halt at 700 ppm KCN after 72 h incubation. In this study, specific growth and degradation rates were found to trail the substrate inhibition kinetics. These two rates fitted well to the kinetic models of Teissier, Luong, Aiba and Heldane, while the performance of Monod model was found to be unsatisfactory. These models were used to clarify the substrate inhibition on the bacteria growth. The analyses of these models have shown that Luong model has fitted the experimental data with the highest coefficient of determination (R2) value of 0.9794 and 0.9582 with the lowest root mean square error (RMSE) value of 0.000204 and 0.001, respectively, for the specific rate of degradation and growth. It is the only model that illustrates the maximum substrate concentration (Sm) of 713.4 and empirical constant (n) of 1.516. Tessier and Aiba fitted the experimental data with a R2 value of 0.8002 and 0.7661 with low RMSE of 0.0006, respectively, for specific biodegradation rate, while having a R2 value of 0.9 and RMSE of 0.001, respectively, for specific growth rate. Haldane has the lowest R2 value of 0.67 and 0.78 for specific biodegradation and growth rate with RMSE of 0.0006 and 0.002, respectively. This indicates the level of the bacteria stability in varying concentrations of cyanide and the maximum cyanide concentration it can tolerate within a specific time period. The biokinetic constant predicted from this model demonstrates a good ability of the locally isolated bacteria in cyanide remediation in industrial effluents.
    Matched MeSH terms: Kinetics
  4. Wong LY, Lau SY, Pan S, Lam MK
    Chemosphere, 2022 Jan;287(Pt 2):132129.
    PMID: 34509009 DOI: 10.1016/j.chemosphere.2021.132129
    The suitability and efficacy of three-dimensional (3D) graphene, including its derivatives, have garnered widespread attention towards the development of novel, sustainable materials with ecological amenability. This is especially relevant towards its utilization as adsorbents of wastewater contaminants, such as heavy metals, dyes, and oil, which could be majorly attributed to its noteworthy physicochemical features, particularly elevated chemical and mechanical robustness, advanced permeability, as well as large specific surface area. In this review, we emphasize on the adsorptive elimination of oil particles from contaminated water. Specifically, we assess and collate recent literature on the conceptualization and designing stages of 3D graphene-based adsorbents (3DGBAs) towards oil adsorption, including their applications in either batch or continuous modes. In addition, we analytically evaluate the adsorption mechanism, including sorption sites, physical properties, surface chemistry of 3DGBA and interactions between the adsorbent and adsorbate involving the adsorptive removal of oil, as well as numerous effects of adsorption conditions on the adsorption performance, i.e. pH, temperature, initial concentration of oil contaminants and adsorbent dosage. Furthermore, we focus on the equilibrium isotherms and kinetic studies, in order to comprehend the oil elimination procedures. Lastly, we designate encouraging avenues and recommendations for a perpetual research thrust, and outline the associated future prospects and perspectives.
    Matched MeSH terms: Kinetics
  5. Lim TY, Wagiran H, Hussin R, Hashim S
    Appl Radiat Isot, 2015 Aug;102:10-4.
    PMID: 25933405 DOI: 10.1016/j.apradiso.2015.04.005
    The paper presents the thermoluminescence (TL) response of strontium tetraborate glass subjected to electron irradiations at various Dy2O3 concentrations ranging from 0.00 to 1.00mol%. All glass samples exhibited single broad peak with maximum peak temperature positioned at 170-215°C. The optimum TL response was found at Dy2O3 concentration 0.75mol%. This glass showed good linearity and higher sensitivity for 7MeV compared to 6MeV electrons. Analysis of kinetic parameters showed that the glasses demonstrate second order kinetic.
    Matched MeSH terms: Kinetics
  6. Asdarina, Y., Abdurrahman, H.N., Amirah, N.F.S., Natrah, S.A.R., Norasmah, M.M., Zulkafli, H.
    MyJurnal
    Increasing demands in palm oil industry hence resulting the production of palm oil to increase. It is then creating a major problem in disposing the waste to be treat in appropriate ways. The governments are forced to look for alternative technology for the palm oil mill effluent (POME) treatment because the demand of oil increases with the awareness on increasing environmental issue. Therefore, a new technology must be found in order to reduce energy consumption, to meet legal requirements on emission and for cost reduction and also increased quality of water treatment. Membrane Anaerobic System (MAS) is a promising alternative way to overcome these issues. In this study, the efficiency of the MAS performance increases to 99.03% in ten days operation. The application of Monod, Contois and Chen & Hashimoto models were used to analyze the performance of MAS for treating POME. The results from the experiment show the substrate removal model is well fits for estimation of kinetics membrane anaerobic system. Amongst them, the Contois and Monod models predicted the bio-kinetic reactions of the MAS very well with coefficient of determination (R2>97%) values. The MAS bioreactor was creating to be an improvement method as well as successful biological treatment since the graph shows linearized which is good agreement with reported in literature.
    Matched MeSH terms: Kinetics
  7. Hussin MH, Pohan NA, Garba ZN, Kassim MJ, Rahim AA, Brosse N, et al.
    Int J Biol Macromol, 2016 Jun 30;92:11-19.
    PMID: 27373428 DOI: 10.1016/j.ijbiomac.2016.06.094
    The present study sheds light on the physical and chemical characteristics of microcrystalline cellulose (MCC) isolated from oil palm fronds (OPF) pulps. It was found that the OPF MCC was identified as cellulose II polymorph, with higher crystallinity index than OPF α-cellulose (CrIOPFMCC: 71%>CrIOPFα-cellulose: 47%). This indicates that the acid hydrolysis allows the production of cellulose that is highly crystalline. BET surface area of OPF MCC was found to be higher than OPF α-cellulose (SBETOPFMCC: 5.64m(2)g(-1)>SBETOPFα-cellulose:Qa(0) 2.04m(2)g(-1)), which corroborates their potential as an adsorbent. In batch adsorption studies, it was observed that the experimental data fit well with Langmuir adsorption isotherm in comparison to Freundlich isotherm. The monolayer adsorption capacity (Qa(0)) of OPF MCC was found to be around 51.811mgg(-1) and the experimental data fitted well to pseudo-second-order kinetic model.
    Matched MeSH terms: Kinetics
  8. Othman, N., Kamarudin, S.K., Mamat, M.R., Azman, A., Rosli, M.I., Takrif, M.S.
    MyJurnal
    In this study, the numerical simulation in a mixing vessel agitated by a six bladed Rushton turbine has
    been carried out to investigate the effects of effective parameters to the mixing process. The study is intended to screen the potential parameters which affect the optimization process and to provide the detail insights into the process. Three-dimensional and steady-state flow has been performed using the fully predictive Multiple Reference Frame (MRF) technique for the impeller and tank geometry. Process optimization is always used to ensure the optimum conditions are fulfilled to attain industries’ satisfaction or needs (ie; increase profit, low cost, yields, etc). In this study, the range of recommended speed to accelerate optimization is 100, 150 and 200rpm respectively and the range of recommended clearance is 50, 75 and 100mm respectively for dual Rushton impeller. Thus, the computer fluid dynamics (CFD) was introduced in order to screen the suitable parameters efficiently and to accelerate optimization. In this study,
    Matched MeSH terms: Kinetics
  9. Firdaus Kamaruzaman, Siti Habibah Shafiai
    MyJurnal
    Lattice Boltzmann Model for Shallow Water Equation with Turbulence Modeling (LABSWETM) is used to study the flow patterns of sidewall friction effects. The lattice Boltzmann method (LBM) approach in recovery the macroscopic governing equation which is shallow water equation from the microscopic flow behavior of particle movement as described by kinetic theory is explored. With the solution of force term to be used in lattice Boltzmann equation, the boundary condition of LBM is explored. With the use of bed and wall friction coefficients, the importance of Manning’s coefficient in determining the outcome of flow patterns simulation is explained. For model verification, the model represents a straight channel with a circular cavity attached to it. The result of this simulation includes the water circulation patterns, cross-section of average velocity distribution, and water depth. For validation, the cross-sections of the model in term of velocity vectors are compared against alternative numerical and experimental data.
    Matched MeSH terms: Kinetics
  10. Jesudason, C.G.
    ASM Science Journal, 2007;1(1):7-18.
    MyJurnal
    Molecular dynamics reaction simulation showed that the rate constant is not constant over the concentration profile of reactants and products over a fixed temperature regime, and this variation is expressed in terms of the defined reactivity coefficients. The ratio of these coefficients for the forward and backward reactions were found to equal that of the activity coefficient ratio for the product and reactant species. A theory was developed to explain kinetics in general based on these observations. Several other theorems had first to be developed, most striking of all was the inference that the excess Helmholtz free energy was the thermodynamical function which had a direct relation to these activity factors than the Gibbs free energy. The theory is applied to a class of ionic reactions which could not be rationalized using the standard Bjørn-Bjerrum theory of ionic reactions.
    Matched MeSH terms: Kinetics
  11. Syafiuddin A, Salmiati S, Jonbi J, Fulazzaky MA
    J Environ Manage, 2018 Jul 15;218:59-70.
    PMID: 29665487 DOI: 10.1016/j.jenvman.2018.03.066
    It is the first time to do investigation the reliability and validity of thirty kinetic and isotherm models for describing the behaviors of adsorption of silver nanoparticles (AgNPs) onto different adsorbents. The purpose of this study is therefore to assess the most reliable models for the adsorption of AgNPs onto feasibility of an adsorbent. The fifteen kinetic models and fifteen isotherm models were used to test secondary data of AgNPs adsorption collected from the various data sources. The rankings of arithmetic mean were estimated based on the six statistical analysis methods of using a dedicated software of the MATLAB Optimization Toolbox with a least square curve fitting function. The use of fractal-like mixed 1, 2-order model for describing the adsorption kinetics and that of Fritz-Schlunder and Baudu models for describing the adsorption isotherms can be recommended as the most reliable models for AgNPs adsorption onto the natural and synthetic adsorbent materials. The application of thirty models have been identified for the adsorption of AgNPs to clarify the usefulness of both groups of the kinetic and isotherm equations in the rank order of the levels of accuracy, and this significantly contributes to understandability and usability of the proper models and makes to knowledge beyond the existing literatures.
    Matched MeSH terms: Kinetics
  12. Loy ACM, Gan DKW, Yusup S, Chin BLF, Lam MK, Shahbaz M, et al.
    Bioresour Technol, 2018 Aug;261:213-222.
    PMID: 29665455 DOI: 10.1016/j.biortech.2018.04.020
    The thermal degradation behaviour and kinetic parameter of non-catalytic and catalytic pyrolysis of rice husk (RH) using rice hull ash (RHA) as catalyst were investigated using thermogravimetric analysis at four different heating rates of 10, 20, 50 and 100 K/min. Four different iso conversional kinetic models such as Kissinger, Friedman, Kissinger-Akahira-Sunose (KAS) and Ozawa-Flynn-Wall (OFW) were applied in this study to calculate the activation energy (EA) and pre-exponential value (A) of the system. The EA of non-catalytic and catalytic pyrolysis was found to be in the range of 152-190 kJ/mol and 146-153 kJ/mol, respectively. The results showed that the catalytic pyrolysis of RH had resulted in a lower EA as compared to non-catalytic pyrolysis of RH and other biomass in literature. Furthermore, the high Gibb's free energy obtained in RH implied that it has the potential to serve as a source of bioenergy production.
    Matched MeSH terms: Kinetics
  13. Moss B, Lim KK, Beltram A, Moniz S, Tang J, Fornasiero P, et al.
    Sci Rep, 2017 06 07;7(1):2938.
    PMID: 28592816 DOI: 10.1038/s41598-017-03065-5
    In this article we present the first comparative study of the transient decay dynamics of photo-generated charges for the three polymorphs of TiO2. To our knowledge, this is the first such study of the brookite phase of TiO2 over timescales relevant to the kinetics of water splitting. We find that the behavior of brookite, both in the dynamics of relaxation of photo-generated charges and in energetic distribution, is similar to the anatase phase of TiO2. Moreover, links between the rate of recombination of charge carriers, their energetic distribution and the mode of transport are made in light of our findings and used to account for the differences in water splitting efficiency observed across the three polymorphs.
    Matched MeSH terms: Kinetics
  14. Fulazzaky MA, Nuid M, Aris A, Muda K
    Environ Technol, 2018 Sep;39(17):2151-2161.
    PMID: 28675960 DOI: 10.1080/09593330.2017.1351494
    Understanding of mass transfer kinetics is important for biosorption of nitrogen compounds from palm oil mill effluent (POME) to gain a mechanistic insight into future biological processes for the treatment of high organic loading wastewater. In this study, the rates of global and sequential mass transfer were determined using the modified mass transfer factor equations for the experiments to remove nitrogen by aerobic granular sludge accumulation in a sequencing batch reactor (SBR). The maximum efficiencies as high as 97% for the experiment run at [kLa]g value of 1421.8 h-1 and 96% for the experiment run at [kLa]g value of 9.6 × 1037 h-1 were verified before and after the addition of Serratia marcescens SA30, respectively. The resistance of mass transfer could be dependent on external mass transfer that controls the transport of nitrogen molecule along the experimental period of 256 days. The increase in [kLa]g value leading to increased performance of the SBR was verified to contribute to the future applications of the SBR because this phenomenon provides new insight into the dynamic response of biological processes to treat POME.
    Matched MeSH terms: Kinetics
  15. Zal U'yun Wan Mahmood, Norfaizal Mohamad, Nur Nazirah Johari
    MyJurnal
    Accumulation kinetic trends of cesium and cadmium in the Penaeus monodon were studied using Cs-134 and Cd-109 as a tracer. The objective of this study was to quantify the uptake and loss/depuration kinetic of these two radionuclides in the Penaeus monodon. Uptake and loss/depuration kinetic of these two radionuclides in the Penaeus monodon were varied widely, displayed a simple double kinetic model of linear and exponential trend with time unless modified by moulting at the stage in the mount cycle. Therefore, the variation of Cs-134 and Cd-109 bio-concentration factor could be concluded considerably influence by moulting cycle, environmental and biological condition as well as physico-chemical that direct effects on their uptake and loss/depuration kinetic.
    Matched MeSH terms: Kinetics
  16. Salleh MA, Gourlay CM, Xian JW, Belyakov SA, Yasuda H, McDonald SD, et al.
    Sci Rep, 2017 01 12;7:40010.
    PMID: 28079120 DOI: 10.1038/srep40010
    The development of microstructure during melting, reactive wetting and solidification of solder pastes on Cu-plated printed circuit boards has been studied by synchrotron radiography. Using Sn-3.0Ag-0.5Cu/Cu and Sn-0.7Cu/Cu as examples, we show that the interfacial Cu6Sn5 layer is present within 0.05 s of wetting, and explore the kinetics of flux void formation at the interface between the liquid and the Cu6Sn5 layer. Quantification of the nucleation locations and anisotropic growth kinetics of primary Cu6Sn5 crystals reveals a competition between the nucleation of Cu6Sn5 in the liquid versus growth of Cu6Sn5 from the existing Cu6Sn5 layer. Direct imaging confirms that the β-Sn nucleates at/near the Cu6Sn5 layer in Sn-3.0Ag-0.5Cu/Cu joints.
    Matched MeSH terms: Kinetics
  17. Micky Vincent, Latifah Suali, Afizul Safwan Azahari, Patricia Rowena Mark Baran, Elexson Nillian, Lesley Maurice Bilung
    MyJurnal
    Yeast growth and biomass production are greatly influenced by the length of the
    incubation period during cultivation. Therefore, this study was conducted to
    investigate the growth kinetics of five Lipomyces starkeyi strains as determined by
    biomass production. The five L. starkeyi strains, namely L. starkeyi ATCC 12659, L.
    starkeyi MV-1, L. starkeyi MV-4, L. starkeyi MV-5 and L. starkeyi MV-8, were inoculated
    in sterilized Yeast Malt broth, and, incubated for 192 hr at ambient temperature.
    Biomass yields were assessed and calculated gravimetrically every 24 hr. Results
    indicated that the optimal biomass production of L. starkeyi ATCC 12659, L. starkeyi
    MV-1, L. starkeyi MV-4, L. starkeyi MV-5 and L. starkeyi MV-8 were at 120, 168, 144,
    168 and 120 hr, with the concentrations of 6.64, 6.43, 9.78, 11.23 and 8.56 g/L,
    respectively. These results indicate that each L. starkeyi strain requires specific
    incubation period for the optimum production of fungal biomass. Therefore, by
    cultivating each L. starkeyi strain at the predetermined incubation period, biomass
    yields could significantly be improved for further downstream applications such as
    single cell protein and lipid production.
    Matched MeSH terms: Kinetics
  18. Choong TSY, Yeoh CM, Phuah ET, Siew WL, Lee YY, Tang TK, et al.
    PLoS One, 2018;13(2):e0192375.
    PMID: 29401481 DOI: 10.1371/journal.pone.0192375
    Diacylglycerol (DAG) and monoacylglycerol (MAG) are two natural occurring minor components found in most edible fats and oils. These compounds have gained increasing market demand owing to their unique physicochemical properties. Enzymatic glycerolysis in solvent-free system might be a promising approach in producing DAG and MAG-enriched oil. Understanding on glycerolysis mechanism is therefore of great importance for process simulation and optimization. In this study, a commercial immobilized lipase (Lipozyme TL IM) was used to catalyze the glycerolysis reaction. The kinetics of enzymatic glycerolysis reaction between triacylglycerol (TAG) and glycerol (G) were modeled using rate equation with unsteady-state assumption. Ternary complex, ping-pong bi-bi and complex ping-pong bi-bi models were proposed and compared in this study. The reaction rate constants were determined using non-linear regression and sum of square errors (SSE) were minimized. Present work revealed satisfactory agreement between experimental data and the result generated by complex ping-pong bi-bi model as compared to other models. The proposed kinetic model would facilitate understanding on enzymatic glycerolysis for DAG and MAG production and design optimization of a pilot-scale reactor.
    Matched MeSH terms: Kinetics
  19. Yiin CL, Yusup S, Quitain AT, Uemura Y, Sasaki M, Kida T
    Bioresour Technol, 2018 May;255:189-197.
    PMID: 29414166 DOI: 10.1016/j.biortech.2018.01.132
    The impacts of low-transition-temperature mixtures (LTTMs) pretreatment on thermal decomposition and kinetics of empty fruit bunch (EFB) were investigated by thermogravimetric analysis. EFB was pretreated with the LTTMs under different duration of pretreatment which enabled various degrees of alteration to their structure. The TG-DTG curves showed that LTTMs pretreatment on EFB shifted the temperature and rate of decomposition to higher values. The EFB pretreated with sucrose and choline chloride-based LTTMs had attained the highest mass loss of volatile matter (78.69% and 75.71%) after 18 h of pretreatment. For monosodium glutamate-based LTTMs, the 24 h pretreated EFB had achieved the maximum mass loss (76.1%). Based on the Coats-Redfern integral method, the LTTMs pretreatment led to an increase in activation energy of the thermal decomposition of EFB from 80.00 to 82.82-94.80 kJ/mol. The activation energy was mainly affected by the demineralization and alteration in cellulose crystallinity after LTTMs pretreatment.
    Matched MeSH terms: Kinetics
  20. Nur Shazwani Abdul Mubarak, S. Sabar, Ali H. Jawad
    Science Letters, 2020;14(1):68-83.
    MyJurnal
    Commercial titanium dioxide Degussa P25 (TiO2) was used for the adsorption of reactive red 120
    (RR120) dye in a batch system. The optimization functions such as solution pH (3-12), adsorbent dosage (0.02 g-1.2 g), and initial dye concentration (30-400 mg/L) were studied. The equilibrium adsorption data for RR120 dye was analyzed by two types of isotherm models which are Langmuir and Freundlich models. The adsorption at equilibrium showed a better fit for linear Langmuir isotherm with the adsorption capacity, qmax of 18.62 mg/g at 303 K. The adsorption kinetic was well-described by pseudosecond order model. TiO2 showed a decent outcome due to the ability to adsorb target pollutants with theadded advantage of providing large hydroxyl groups (OH) on the surface of TiO2 so that pollutants can be adsorbed by interacting on the surface of OH.
    Matched MeSH terms: Kinetics
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