Displaying publications 21 - 40 of 240 in total

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  1. Abdollahi Y, Sairi NA, Said SB, Abouzari-lotf E, Zakaria A, Sabri MF, et al.
    PMID: 26119355 DOI: 10.1016/j.saa.2015.06.036
    It is believe that 80% industrial of carbon dioxide can be controlled by separation and storage technologies which use the blended ionic liquids absorber. Among the blended absorbers, the mixture of water, N-methyldiethanolamine (MDEA) and guanidinium trifluoromethane sulfonate (gua) has presented the superior stripping qualities. However, the blended solution has illustrated high viscosity that affects the cost of separation process. In this work, the blended fabrication was scheduled with is the process arranging, controlling and optimizing. Therefore, the blend's components and operating temperature were modeled and optimized as input effective variables to minimize its viscosity as the final output by using back-propagation artificial neural network (ANN). The modeling was carried out by four mathematical algorithms with individual experimental design to obtain the optimum topology using root mean squared error (RMSE), R-squared (R(2)) and absolute average deviation (AAD). As a result, the final model (QP-4-8-1) with minimum RMSE and AAD as well as the highest R(2) was selected to navigate the fabrication of the blended solution. Therefore, the model was applied to obtain the optimum initial level of the input variables which were included temperature 303-323 K, x[gua], 0-0.033, x[MDAE], 0.3-0.4, and x[H2O], 0.7-1.0. Moreover, the model has obtained the relative importance ordered of the variables which included x[gua]>temperature>x[MDEA]>x[H2O]. Therefore, none of the variables was negligible in the fabrication. Furthermore, the model predicted the optimum points of the variables to minimize the viscosity which was validated by further experiments. The validated results confirmed the model schedulability. Accordingly, ANN succeeds to model the initial components of the blended solutions as absorber of CO2 capture in separation technologies that is able to industries scale up.
    Matched MeSH terms: Viscosity
  2. Hayat T, Abbasi F, Ahmad B, Alsaedi A
    Sains Malaysiana, 2014;43:1583-1590.
    This article concerns with a mixed convection peristaltic flow of an electrically conducting fluid in an inclined asymmetric channel. Analysis has been carried out in the presence of Joule heating. The fluid viscosity and thermal conductivity are assumed to vary as a linear function of temperature. A nonlinear coupled governing system is computed. Numerical results were presented for the velocity, pressure gradient, temperature and streamlines. Heat transfer rate at the wall is computed and analyzed. Graphs reflecting the contributions of embedded parameters were discussed.
    Matched MeSH terms: Viscosity
  3. Uddin MJ, Khan WA, Amin NS
    PLoS One, 2014;9(6):e99384.
    PMID: 24927277 DOI: 10.1371/journal.pone.0099384
    The unsteady two-dimensional laminar g-Jitter mixed convective boundary layer flow of Cu-water and Al2O3-water nanofluids past a permeable stretching sheet in a Darcian porous is studied by using an implicit finite difference numerical method with quasi-linearization technique. It is assumed that the plate is subjected to velocity and thermal slip boundary conditions. We have considered temperature dependent viscosity. The governing boundary layer equations are converted into non-similar equations using suitable transformations, before being solved numerically. The transport equations have been shown to be controlled by a number of parameters including viscosity parameter, Darcy number, nanoparticle volume fraction, Prandtl number, velocity slip, thermal slip, suction/injection and mixed convection parameters. The dimensionless velocity and temperature profiles as well as friction factor and heat transfer rates are presented graphically and discussed. It is found that the velocity reduces with velocity slip parameter for both nanofluids for fluid with both constant and variable properties. It is further found that the skin friction decreases with both Darcy number and momentum slip parameter while it increases with viscosity variation parameter. The surface temperature increases as the dimensionless time increases for both nanofluids. Nusselt numbers increase with mixed convection parameter and Darcy numbers and decreases with the momentum slip. Excellent agreement is found between the numerical results of the present paper with published results.
    Matched MeSH terms: Viscosity
  4. Salleh KM, Zakaria S, Sajab MS, Gan S, Chia CH, Jaafar SNS, et al.
    Int J Biol Macromol, 2018 Oct 15;118(Pt B):1422-1430.
    PMID: 29964115 DOI: 10.1016/j.ijbiomac.2018.06.159
    Dissolved oil palm empty fruit bunch (EFB) cellulose in NaOH/urea solvent was mixed with sodium carboxymethylcellulose (NaCMC) to form a green regenerated superabsorbent hydrogel. The effect of concentration of epichlorohydrin (ECH) as the crosslinker on the formation, physical, and chemical properties of hydrogel was studied. Rapid formation and higher gel content of hydrogel were observed at 10% concentration of ECH. The superabsorbent hydrogel was successfully fabricated in this study with the swelling ability >100,000%. Hydrogel with higher concentration of ECH showed opposite trend by having higher superabsorbent property than that of lower concentration. The covalent bond of COC was observed with Attenuated total reflectance fourier transform infrared (ATR-FT-IR) spectroscopy to confirm the occurrence of crosslinking. The physical and chemical properties of hydrogel were affected by swelling phenomenon. Hydrogel with higher degree of swelling exhibited lower moisture retention and higher transparency. Moreover, the weight of the superabsorbent hydrogel increased with the decrement of pH value of external media (distilled water). This study provided substantial information on the effect of different percentage of ECH as crosslinker on hydrogel basic properties. Furthermore, this study affords correlation of many essential driving forces that affected hydrogel superabsorbent property.
    Matched MeSH terms: Viscosity
  5. Mohammed Saifuddin, Amru N. Boyce
    Sains Malaysiana, 2017;46:1771-1778.
    As fossil energy resources are depleting quick and energy security is playing a vital role in the world economy. Quest for alternative energy sources have turned researches investigation in waste foods for next generation fuel. Biodiesel is usually considered to be environmentally friendly as it reduces greenhouse gas emission. Fish wastes rich in fatty acids and can be used as the raw material to produce biodiesel through transesterification reaction. The results showed that the seven peaks are fatty acid methyl esters, indicating all the triglycerides were successfully methylated to methyl esters. Fish based biodiesel provided a significant reduction in carbon monoxide (CO) and hydrocarbon (HC) emissions under engine loads of 15 (Nm) and required no engine modification. The viscosity of the produced biodiesel was within the range of international standards (ASTM). The biodiesel was found to contain a low base number and exhibited a lower specific fuel consumption compared to the conventional diesel. It can be concluded that biodiesel derived from waste fish oil can be considered as a potential source of commercial biodiesel.
    Matched MeSH terms: Viscosity
  6. Muhammad Khairul Anuar Mohamed, Nor Aida Zuraimi Md Noar, Mohd Zuki Salleh, Anuar Ishak
    Sains Malaysiana, 2016;45:189-296.
    In this paper, the problem of free convection boundary layer flow on a horizontal circular cylinder in a nanofluid with viscous dissipation and constant wall temperature is investigated. The transformed boundary layer equations are solved numerically using finite difference scheme namely the Keller-box method. Numerical solutions were obtained for the reduced skin friction coefficient, Nusselt number and Sherwood number as well as the velocity and temperature profiles.The features of the flow and heat transfer characteristics for various values of the Brownian motion parameter, thermophoresis parameter, Lewis number and Eckert number were analyzed and discussed.
    Matched MeSH terms: Viscosity
  7. Abu Zarim N, Zainul Abidin S, Ariffin F
    J Food Sci Technol, 2018 Nov;55(11):4522-4529.
    PMID: 30333649 DOI: 10.1007/s13197-018-3386-5
    Texture-modified food has become an important strategy in managing dysphagia. Pureed food is proven to be the safest texture due to its high viscosity which can slow down the rate of the food bolus during swallowing. In this study, texture-modified chicken rendang was developed according to Texture C (smooth puree) as described by the Australian standard for texture-modified food. Samples were added with five different thickeners (sago starch, tapioca starch, modified corn starch, xanthan gum and carboxymethyl cellulose gum) at three different concentrations (10, 20 and 30% w/w). Their rheological effects were analyzed through dynamic and steady shear test. Results obtained reveals that samples contained xanthan gum have higher structure rigidity and shear thinning behaviour, while carboxymethyl cellulose gum provides the highest viscosity as well as yield stress than other samples. In terms of concentration, a strong dependence of structural rigidity and viscosity of all prepared samples with amount of thickeners added was observed. Overall, based on its rheological properties, the addition of carboxymethyl cellulose gum at 30% concentration was found to be the most suitable thickener, to be incorporated in the texture-modified chicken rendang. Selecting a suitable food thickener in developing food for individual with dysphagia plays an important role to ensure the right texture and consistency for their safe consumption.
    Matched MeSH terms: Viscosity
  8. Gopinath, V.K., Arzreanne , A.R.
    MyJurnal
    The objective of this study was to evaluate the effects of salivary testing in dental caries assessment. The role of saliva flow rate, pH, viscosity and buffering capacity in subjects with high caries (DMFT>5) (group 1) against subjects with low caries (DMFT=0) (control group) were evaluated. 40 subjects between the age of 18 and 40 years old were selected (20 subjects control group and 20 subjects group 1). By using a salivary testing kit (GC Asia Dental Pte Ltd, Japan), each subject underwent test such as hydration status of the oral mucosa, viscosity and pH of resting saliva, stimulated salivary flow rate and buffering capacity of stimulated saliva. The results showed that the flow rate, viscosity, pH and buffering capacity of saliva in subjects of group 1 (DMFT>5) was significantly lower (p
    Matched MeSH terms: Viscosity
  9. Abd Ghani Aizat, Paiman, Bawon, Lee, Seng Hua, Ashaari Zaidon
    MyJurnal
    In this study, the effects of addition of ammonium and aluminium-based hardeners into
    urea formaldehyde resin (UF) on the physico-mechanical properties and formaldehyde
    emission of the rubberwood particleboard were investigated. Four types of hardeners,
    namely ammonium chloride (AC), ammonium sulphate (AS), aluminium chloride (AlC)
    and aluminium sulphate (AlS), were added into UF resin. The acidity, gelation time,
    viscosity and free formaldehyde content of the UF/hardener mixtures were determined.
    Particleboard made with the UF/hardener mixtures were tested for physico-mechanical
    properties and formaldehyde emission. The pH values of the resin after addition of
    aluminium-based hardeners were higher and resulted in higher viscosity and shorter
    gelation time. Consequently, despite lower formaldehyde emission was recorded, the
    physico-mechanical properties of the resulted particleboard were inferior compared to
    that of ammonium-based hardeners. The best quality particleboard in terms of mechanical,
    physical and formaldehyde emission were obtained from the particleboard made with AS,
    followed by AC.
    Matched MeSH terms: Viscosity
  10. Yusrabbil Amiyati Yusof, Zafarizal Aldrin Azizul Hasan, Azhar Ariffin
    Sains Malaysiana, 2018;47:511-515.
    This paper reports the effects of glyceryl ether specifically mono-tert-butoxypropanediol on oil in water emulsion system.
    Based on 12 HLB value, screening for stable emulsions was carried out without the presence of glyceryl ether. A stable
    emulsion was used as a control. Then the effects of glyceryl ether on the emulsion system were investigated. The emulsions
    prepared were analyzed for stability, viscosity, pH value, particle size, in vitro dermal irritation potential, in vitro ocular
    irritation potential and also moisturizing property. The incorporation of glycerol in the emulsion system was also done
    for comparison. Emulsions with glyceryl ether showed lower viscosity values than emulsions with glycerol. Furthermore,
    the emulsions also exhibited moisturizing property compared to the control emulsion. Glyceryl ether is suitable to be
    used in cosmetic products which require reduced viscosity but retain its skin hydration property.
    Matched MeSH terms: Viscosity
  11. Abbas, F.M.A., Saifullah, R., Azhar, M.E.
    MyJurnal
    Physical properties of ripe banana flour were studied in Cavendish and Dream banana, in order to distinguish the two varieties. Flour was analyzed for pH, total soluble solids (TSS), water holding capacity
    (WHC) and oil holding capacity (OHC) at 40, 60 and 80 °C, color values L*, a* and b*, back extrusion force
    and viscosity. Physical properties data were analyzed by cluster analysis (CA) and discriminant analysis (DA). CA showed that the two types of flour were different in terms of selected physical properties. DA indicated that WHC at 60 °C was the main contributor in discriminating the two types of flour.
    Matched MeSH terms: Viscosity
  12. Nor Azura Abdul Rahim, Zulkifli Mohamad Ariff, Azlan Ariffin
    MyJurnal
    A study of kaolin addition in polypropylene (PP-kaolin) melt was carried out to characterize its flow behaviour and viscoelasticity at different temperatures. The compound of 20 wt% kaolin was prepared by melt mixing using two roll-mill heated at 185°C, while the compounded composites were put through a single screw extruder to evaluate its melt flow properties. The prepared PPKaolin composites exhibited a shear thinning behaviour and appeared to be strongly dependent on temperature. Moreover, it was also found that the power law index was constantly increased as the temperature increased. Meanwhile, a similar trend was observed for swelling ratio, whereby it also increased with increasing temperature. It was also observed that changes in the die temperatures would result in the formation of obvious bubble like surface morphology, and it became more prominent when the temperature was lowered.
    Matched MeSH terms: Viscosity
  13. Zainon SNM, Azmi WH
    Micromachines (Basel), 2021 Feb 11;12(2).
    PMID: 33670250 DOI: 10.3390/mi12020176
    Many studies have shown the remarkable enhancement of thermo-physical properties with the addition of a small quantity of nanoparticles into conventional fluids. However, the long-term stability of the nanofluids, which plays a significant role in enhancing these properties, is hard to achieve, thus limiting the performance of the heat transfer fluids in practical applications. The present paper attempts to highlight various approaches used by researchers in improving and evaluating the stability of thermal fluids and thoroughly explores various factors that contribute to the enhancement of the thermo-physical properties of mono, hybrid, and green nanofluids. There are various methods to maintain the stability of nanofluids, but this paper particularly focuses on the sonication process, pH modification, and the use of surfactant. In addition, the common techniques to evaluate the stability of nanofluids are undertaken by using visual observation, TEM, FESEM, XRD, zeta potential analysis, and UV-Vis spectroscopy. Prior investigations revealed that the type of nanoparticle, particle volume concentration, size and shape of particles, temperature, and base fluids highly influence the thermo-physical properties of nanofluids. In conclusion, this paper summarized the findings and strategies to enhance the stability and factors affecting the thermal conductivity and dynamic viscosity of mono and hybrid of nanofluids towards green nanofluids.
    Matched MeSH terms: Viscosity
  14. See SF, Ghassem M, Mamot S, Babji AS
    J Food Sci Technol, 2015 Feb;52(2):753-62.
    PMID: 25694683 DOI: 10.1007/s13197-013-1043-6
    Pretreatments with different types of alkali and acid were compared to determine their effects on gelatin extraction from African catfish (Clarias gariepinus) skin. The study was divided into three parts. In the first part, the skins were only treated with alkaline (Ca(OH)2 or NaOH) solution or pretreated with acetic acid solution. For second part, combination of alkali and acid pretreatment was carried out. For the third part, the skins were first treated with NaOH solution, followed by the treatment with acetic acid, citric acid or sulfuric acid solution. Functional properties including the yield of protein recovery, gel strength, viscosity, pH and viscoelastic properties were determined on gelatins obtained with different pretreatment conditions. Pretreatment with alkali removed noncollagenous proteins effectively, whilst acid pretreatment induced some loss of collagenous proteins. Combination of alkali and acid pretreatment not only removed the noncollagenous proteins and caused a significant amount of swelling, but also provided the proper pH condition for extraction, during which some cross-linkages could be further destroyed but with less breakage of intramolecular peptide chains. Pretreatment of catfish skins with 0.2 N NaOH followed by 0.05 M acetic acid improved yield of protein recovery, gel strength, viscosity, melting temperature and gelling temperature of gelatin extract.
    Matched MeSH terms: Viscosity
  15. Mahmoodani F, Ardekani VS, See SF, Yusop SM, Babji AS
    J Food Sci Technol, 2014 Nov;51(11):3104-13.
    PMID: 26396302 DOI: 10.1007/s13197-012-0816-7
    In the present study, to establish the optimum gelatin extraction conditions from pangasius catfish (Pangasius sutchi) bone, Response Surface Methodology (RSM) with a 4-factor, 5-level Central Composite Design (CCD) was conducted. The model equation was proposed with regard to the effects of HCl concentration (%, X1), treatment time (h, X2), extraction temperature (°C, X3) and extraction time (h, X4) as independent variables on the hydroxyproline recovery (%, Y) as dependent variable. X 1 = 2.74 %, X 2 = 21.15 h, X 3 = 74.73 °C and X 4 = 5.26 h were found to be the optimum conditions to obtain the highest hydroxyproline recovery (68.75 %). The properties of optimized catfish bone gelatin were characterized by amino acid analysis, SDS-PAGE, gel strength, TPA and viscosity in comparison to bovine skin gelatin. The result of SDS-PAGE revealed that pangasius catfish bone gelatin consisted of at least 2 different polypeptides (α1 and α2 chains) and their cross-linked chains. Moreover, the pangasius catfish bone gelatin was found to contain 17.37 (g/100 g) imino acids (proline and hydroxyproline). Pangasius catfish bone gelatin also indicated physical properties comparable with that of bovine and higher than those from cold water fish gelatin. Based on the results of the present study, there is a potential for exploitation of pangasius catfish bone for gelatin production. Furthermore, RSM provided the best method for optimizing the gelatin extraction parameters.
    Matched MeSH terms: Viscosity
  16. Sanaei, A.V., Mahmoodani, F., See, S.F., Yusop, S.M., Babji, A.S.
    MyJurnal
    The extraction of catfish (Clarias gariepinus) bone gelatin was optimized by using Response Surface Methodology (RSM) involving 4-factors, 5-levels Central Composite Design (CCD). The optimum conditions for extraction were produced by a pre-treatment of 3.35% HCl for 14.5 h along with hot water extraction at 67.23°C for 5.2 h. Results showed that the predicted yield by RSM (61.81%) was closely matched the experimental yield of 60.54%. The results also indicated that the extracted bone gelatin possessed high protein content (81.75%) and imino acid (proline and hydroxyproline) (144 residues per 1000 residues), with gel strength (230.25 g), viscosity (4.64 mPa.s) and isoionic point (5.35) comparable to that of bovine gelatin. The results suggested that RSM is a great optimizing tool for extraction of gelatin from clarias catfish bone and values of the physicochemical properties of gelatin are higher or comparable than those from other fish species and bovine gelatin.
    Matched MeSH terms: Viscosity
  17. Quek DKL, George E, Sahak S, Baharim Z
    Family Physician, 1991;3:39-44.
    Haematologic abnormalities are found in patients who develop acute ischaemic syndromes including acute myocardial infarction (AMI). A coronary care unit population of 660 consecutive patients were studied for their haematologic parameters on admission. There were 263 patients who had AMI, 207 who had non-infarct acute ischaemic syndromes (CAD), and the other 190 non-coronary patients served as controls. Overall patients with AMI had signijicantly higher haemoglobin (145 ± 2.2 vs 12.9 ± 3.0 g/dl, p<0.0001), haematocrit (45.4 ± 5.8% vs 41.2 ± 8.8%. P < 0.001). red cell count (5.0 ± 0.7 vs 4.5 ± 10^12 p<0.001), but there were no significant differences in their leucocyte count, platelet count or mean corpuscular volume. Patients with CAD had higher haemoglobin and red cell counts (p<0.002, p<0.02 respectively). Although infarct women tended to have lower counts (p<0.001), they still had significantly higher haemoglobin (p<0.01), haematocrit (p<0.02) and red cell count(p<0.002) when compared with controls. Interestingly, there were no ethnic differences at all with regard to haematologic values for infarct patients; haemoglobin, haematocrit, and red count were each significantly higher than controls. Our results suggest that a relatively high baseline Hb, haematocrit or RBC count may be associated with increased likelihood of acute ischaemic syndromes including AMI among Malaysians. Increased viscosity and abnormal haemorheological characteristics may contribute to the development and subsequent outcome of unstable coronary syndromes. Keywords: acute myocardial infarction, coronary artery disease, haemoglobin, haematocrit, haemorheology.
    Matched MeSH terms: Viscosity
  18. Solati Z, Baharin BS
    J Food Sci Technol, 2015 Jun;52(6):3475-84.
    PMID: 26028729 DOI: 10.1007/s13197-014-1409-4
    Effect of supercritical CO2 extracted Nigella sativa L. seed extract (NE) on frying performance of sunflower oil and refined, bleached and deodorized (RBD) palm olein was investigated at concentrations of 1.2 % and 1.0 % respectively. Two frying systems containing 0 % N. sativa L. extract (Control) and 0.02 % butylated hydroxytoluene (BHT) were used for comparison. Physicochemical properties such as fatty acid composition (FAC), Peroxide Value (PV), Anisidine Value (AV), Totox Value (TV), Total Polar Content (TPC), C18:2/C16:0 ratio and viscosity of frying oils were determined during five consecutive days of frying. Results have shown that N. sativa L. extract was able to improve the oxidative stability of both frying oils during the frying process compared to control. The stabilizing effect of antioxidants were in the order of BHT > NE. RBD palm olein was found to be more stable than sunflower oil based on the ratio of linoleic acid (C18:2) to palmitic acid (C16:0) and fatty acid composition.
    Matched MeSH terms: Viscosity
  19. Tan SL, Stanslas J, Basri M, Abedi Karjiban RA, Kirby BP, Sani D, et al.
    Curr Drug Deliv, 2015;12(6):795-804.
    PMID: 26324229
    Carbamzepine (CBZ) was encapsulated in a parenteral oil-in-water nanoemulsion, in an attempt to improve its bioavailability. The particle size, polydispersity index and zeta potential were measured using dynamic light scattering. Other parameters such as pH, osmolality, viscosity, drug loading efficiency and entrapment efficiency were also recorded. Transmission electron microscopy revealed that emulsion droplets were almost spherical in shape and in the nano-range. The in vitro release profile was best characterized by Higuchi's equation. The parenteral nanoemulsion of CBZ showed significantly higher AUC0→5, AUC0→∞, AUMC0→5, AUMC0→∞, Cmax and lower clearance than that of CBZ solution in plasma. Additionally, parenteral nanoemulsion of CBZ showed significantly higher AUC0→∞, AUMC0→∞ and Cmaxthan that of CBZ solution in brain. The parenteral nanoemulsion of CBZ could therefore use as a carrier, worth exploring further for brain targeting.
    Matched MeSH terms: Viscosity
  20. Harun SN, Nordin SA, Gani SSA, Shamsuddin AF, Basri M, Basri HB
    Int J Nanomedicine, 2018;13:2571-2584.
    PMID: 29731632 DOI: 10.2147/IJN.S151788
    Background and aim: Drugs that are effective against diseases in the central nervous system and reach the brain via blood must pass through the blood-brain barrier (BBB), a unique interface that protects against potential harmful molecules. This presents a major challenge in neuro-drug delivery. This study attempts to fabricate the cefuroxime-loaded nanoemulsion (CLN) to increase drug penetration into the brain when parenterally administered.

    Methods: The nanoemulsions were formulated using a high-pressure homogenization technique and were characterized for their physicochemical properties.

    Results: The characterizations revealed a particle size of 100.32±0.75 nm, polydispersity index of 0.18±0.01, zeta potential of -46.9±1.39 mV, viscosity of 1.24±0.34 cps, and osmolality of 285.33±0.58 mOsm/kg, indicating that the nanoemulsion has compatibility for parenteral application. CLN was physicochemically stable within 6 months of storage at 4°C, and the transmission electron microscopy revealed that the CLN droplets were almost spherical in shape. The in vitro release of CLN profile followed a sustained release pattern. The pharmacokinetic profile of CLN showed a significantly higher Cmax, area under the curve (AUC)0-
    t
    , prolonged half-life, and lower total plasma clearance, indicating that the systemic concentration of cefuroxime was higher in CLN-treated rats as compared to cefuroxime-free treated rats. A similar profile was obtained for the biodistribution of cefuroxime in the brain, in which CLN showed a significantly higher Cmax, AUC0-
    t
    , prolonged half-life, and lower clearance as compared to free cefuroxime solution.

    Conclusion: Overall, CLN showed excellent physicochemical properties, fulfilled the requirements for parenteral administration, and presented improved in vivo pharmacokinetic profile, which reflected its practical approach to enhance cefuroxime delivery to the brain.

    Matched MeSH terms: Viscosity
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