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Fulltext Rheological Study of Phenol Formaldehyde Resole Resin Synthesized for Laminate Application

Kamarudin N, Awang Biak DR, Zainal Abidin Z, Cardona F, Sapuan SM

Materials (Basel), 2020 Jun 05;13(11).
PMID: 32516968 DOI: 10.3390/ma13112578

Heat explosions are sometimes observed during the synthesis of phenol formaldehyde (PF) resin. This scenario can be attributed to the high latent heat that was released and not dissipated leading to the occurrence of a runaway reaction. The synthesis temperature and time played important roles in controlling the heat release, hence preventing the resin from hardening during the synthesis process. This study aims to assess the rheological and viscoelasticity behaviors of the PF resin prepared using paraformaldehyde. The prepared PF resin was designed for laminate applications. The rheological behavior of the PF resin was assessed based on the different molar ratios of phenol to paraformaldehyde (P:F) mixed in the formulation. The molar ratios were set at 1.00:1.25, 1.00:1.50 and 1.00:1.75 of P to F, respectively. The rheological study was focused at specific synthesis temperatures, namely 40, 60, 80 and 100 °C. The synthesis time was observed for 240 min; changes in physical structure and viscosity of the PF resins were noted. It was observed that the viscosity values of the PF resins prepared were directly proportional to the synthesis temperature and the formaldehyde content. The PF resin also exhibited shear thickening behavior for all samples synthesized at 60 °C and above. For all PF resin samples synthesized at 60 °C and above, their viscoelasticity results indicated that the storage modulus (G'), loss modulus(G″) and tan δ are proportionally dependent on both the synthesis temperature and the formaldehyde content. Heat explosions were observed during the synthesis of PF resin at the synthesis temperature of 100 °C. This scenario can lead to possible runaway reaction which can also compromise the safety of the operators.

Matched MeSH terms: Viscosity
Preparation and Characterization of Alginate Microparticles Containing a Model Protein for Oral Administration in Gnotobiotic European Sea Bass (Dicentrarchus labrax) Larvae

Yaacob EN, Goethals J, Bajek A, Dierckens K, Bossier P, De Geest BG, et al.

Mar Biotechnol (NY), 2017 Aug;19(4):391-400.
PMID: 28643227 DOI: 10.1007/s10126-017-9758-4

Aquaculture is the fastest growing animal production sector. However, the production of marine fish is still hampered by the high mortality rate in the first few weeks after hatching. Mortality in larvae is often caused by microbial infections. Today, the incorporation of immunostimulants into microparticles provides us new tools to enhance disease resistance in marine larviculture. In this study, we prepared alginate microparticles loaded with the model antigen fluorescein isothiocyanate conjugated-bovine serum albumin. Optimum concentrations of alginate and CaCl2, the correct alginate viscosity and the appropriate preparatory conditions led to the creation of desirable microparticles with the correct size for oral feeding in gnotobiotic European sea bass larvae. The prepared alginate microparticles were stable in sea water and were successfully ingested by gnotobiotic sea bass larvae at day after hatching 7 without causing any negative effects. Results suggest the suitability of this drug delivery system for targeting the innate immune system of fish larvae in order to enhance disease resistance and thus reduce mortality in larviculture.

Matched MeSH terms: Viscosity
Fulltext Electrical unsteady mhd natural convection flow of nanofluid with thermal stratification and heat generation/absorption

Yahaya Shagaiya Daniel, Zainal Abdul Aziz, Zuhaila Ismail, Faisal Salah

MATEMATIKA, 2018;34(2):393-417.
MyJurnal

Analyzed the effects of thermal radiation, chemical reaction, heat gener-
ation/absorption, magnetic and electric fields on unsteady flow and heat transfer of
nanofluid. The transport equations used passively controlled. A similarity solution is
employed to transformed the governing equations from partial differential equations to
a set of ordinary differential equations, and then solve using Keller box method. It was
found that the temperature is a decreasing function with the thermal stratification due to
the fact the density of the fluid in the lower vicinity is much higher compared to the upper
region, whereas the thermal radiation, viscous dissipation and heat generation enhanced
the nanofluid temperature and thermal layer thickness.

Matched MeSH terms: Viscosity
g-Jitter free convection flow of nanofluid in the three-dimensional stagnation point region

Mohamad Hidayad Ahmad Kamal, Anati Ali, Sharidan Shafie

MATEMATIKA, 2019;35(2):260-270.
MyJurnal

The three dimensional free convection boundary layer flow near a stagnation point region is embedded in viscous nanofluid with the effect of g-jitter is studied in this paper. Copper (Cu) and aluminium oxide (Al2O3) types of water base nanofluid are cho- sen with the constant Prandtl number, Pr=6.2. Based on Tiwari-Das nanofluid model, the boundary layer equation used is converted into a non-dimensional form by adopting non- dimensional variables and is solved numerically by engaging an implicit finite-difference scheme known as Keller-box method. Behaviors of fluid flow such as skin friction and Nusset number are studied by the controlled parameters including oscillation frequency, amplitude of gravity modulation and nanoparticles volume fraction. The reduced skin friction and Nusset number are presented graphically and discussed for different values of principal curvatures ratio at the nodal point. The numerical results shows that, in- crement occurs in the values of Nusset number with the presence of solid nanoparticles together with the values of the skin friction. It is worth mentioning that for the plane stagnation point there is an absence of reduced skin friction along the y-direction where as for axisymmetric stagnation point, the reduced skin friction for both directions are the same. As nanoparticles volume fraction increased, the skin friction increased as well as the Nusset number. The results, indicated that skin frictions of copper are found higher than aluminium oxide.

Matched MeSH terms: Viscosity
Fulltext Carboxymethyl cellulose from palm oil empty fruit bunch - their properties and use as a film coating agent

Amin, M.C.I., Soom, R.M., Ahmad, I., Lian, H.H.

Jurnal Sains Kesihatan Malaysia, 2006;4(2):53-62.
MyJurnal

This study was carried out to determine the physicochemical properties of carboxymethyl cellulose (CMC) derived from cellulose of palm oil empty fruit bunch (EFB) and its use asa film-coating agent. Samples were prepared at various concentrations and then their physicochemical properties were studied including the viscosity, pH, tensile strength of films, surface properties of the films and dissolution studies on coated tablets. CMC EFB showed lower viscosity than commercial CMC product at the concentration of 1%, 2% and 3% with the values of 44.0cp, 299.9cp, 358.9cp and 90.0cp, 689.9cp, 5569.0cp respectively. The tensile strength of the films for CMC EFB were 7.85MPa, 14.79MPa, 10.36MPa while the commercial CMC exhibited higher values of 21.72MPa, 35.14MPa and 26.9MPa at similar concentration. The scanning electron microscope showed different surface properties of the films for both of them where the commercial CMC is smoother in texture and very transparent unlike its counterpart. However, dissolution studies on paracetamol tablets coated using the samples showed no significant difference (p>0.05) in drug release profile between the two materials. Hence, CMC EFB has a greater potential to be developed as a competitive tablet-coating agent despite the differences in its physicochemical properties.

Matched MeSH terms: Viscosity
Physicochemical, textural and viscoelastic properties of palm diacylglycerol bakery shortening during storage

Cheong LZ, Tan CP, Long K, Affandi Yusoff MS, Lai OM

J Sci Food Agric, 2010 Oct;90(13):2310-7.
PMID: 20661900 DOI: 10.1002/jsfa.4088

Diacylglycerol (DAG), which has health-enhancing properties, is sometimes added to bakery shortening to produce baked products with enhanced physical functionality. Nevertheless, the quantity present is often too little to exert any positive healthful effects. This research aimed to produce bakery shortenings containing significant amounts of palm diacyglycerol (PDG). Physicochemical, textural and viscoelastic properties of the PDG bakery shortenings during 3 months storage were evaluated and compared with those of commercial bakery shortening (CS).

Matched MeSH terms: Viscosity
Fabrication of oil-in-water emulsions as shelf-stable liquid non-dairy creamers: effects of homogenization pressure, oil type, and emulsifier concentration

Soo YN, Tan CP, Tan PY, Khalid N, Tan TB

J Sci Food Agric, 2021 Apr;101(6):2455-2462.
PMID: 33034060 DOI: 10.1002/jsfa.10871

BACKGROUND: The popularity of coffee, the second most consumed beverage in the world, contributes to the high demand for liquid non-dairy creamer (LNDC). In this study, palm olein emulsions (as LNDCs) were investigated as alternatives to the more common soybean oil-based LNDCs. LNDCs were prepared via different homogenization pressures (100-300 bar) using different types of oil (palm olein and soybean oil) and concentrations of DATEM emulsifier (5-20 g kg-1 ).
RESULTS: Increases in homogenization pressure and emulsifier concentration were observed to have significant (P 0.05) differences between the prepared and commercial LNDCs in terms of their color, appearance, and overall acceptability.
CONCLUSION: Shelf-stable LNDCs with qualities comparable to commercial LNDC were successfully fabricated. Valuable insights into the effects of homogenization pressure, oil type, and emulsifier concentration, as well as functionality and consumer acceptance of the LNDCs when added into black coffee, were obtained. © 2020 Society of Chemical Industry.

Matched MeSH terms: Viscosity
The nonlinear elastic and viscoelastic passive properties of left ventricular papillary muscle of a guinea pig heart

Hassan MA, Hamdi M, Noma A

J Mech Behav Biomed Mater, 2012 Jan;5(1):99-109.
PMID: 22100084 DOI: 10.1016/j.jmbbm.2011.08.011

The mechanical behavior of the heart muscle tissues is the central problem in finite element simulation of the heart contraction, excitation propagation and development of an artificial heart. Nonlinear elastic and viscoelastic passive material properties of the left ventricular papillary muscle of a guinea pig heart were determined based on in-vitro precise uniaxial and relaxation tests. The nonlinear elastic behavior was modeled by a hypoelastic model and different hyperelastic strain energy functions such as Ogden and Mooney-Rivlin. Nonlinear least square fitting and constrained optimization were conducted under MATLAB and MSC.MARC in order to obtain the model material parameters. The experimental tensile data was used to get the nonlinear elastic mechanical behavior of the heart muscle. However, stress relaxation data was used to determine the relaxation behavior as well as viscosity of the tissues. Viscohyperelastic behavior was constructed by a multiplicative decomposition of a standard Ogden strain energy function, W, for instantaneous deformation and a relaxation function, R(t), in a Prony series form. The study reveals that hypoelastic and hyperelastic (Ogden) models fit the tissue mechanical behaviors well and can be safely used for heart mechanics simulation. Since the characteristic relaxation time (900 s) of heart muscle tissues is very large compared with the actual time of heart beating cycle (800 ms), the effect of viscosity can be reasonably ignored. The amount and type of experimental data has a strong effect on the Ogden parameters. The in vitro passive mechanical properties are good initial values to start running the biosimulation codes for heart mechanics. However, an optimization algorithm is developed, based on clinical intact heart measurements, to estimate and re-correct the material parameters in order to get the in vivo mechanical properties, needed for very accurate bio-simulation and for the development of new materials for the artificial heart.

Matched MeSH terms: Viscosity
Effect of resin coating on highly viscous glass ionomer cements: A dynamic analysis

Yap AU, Ong JE, Yahya NA

J Mech Behav Biomed Mater, 2021 01;113:104120.
PMID: 33086137 DOI: 10.1016/j.jmbbm.2020.104120

OBJECTIVES: This study determined the effects of self-adhesive resin coatings on viscoelastic properties of highly viscous glass ionomer cements (HVGICs) using dynamic mechanical analysis.
MATERIALS AND METHODS: The HVGICs evaluated were Zirconomer [ZR] (Shofu), Equia Forte [EQ] (GC) and Riva [RV] (SDI). Sixty specimens (12mm x 2mm x 2mm) of each material were fabricated using customized Teflon molds. After initial set, the specimens were removed from their molds, finished, measured and randomly divided into 3 groups of 20. Half the specimens in each group were left uncoated while the remaining half was covered with the respective manufacturers' resin coating. The specimens were subsequently conditioned in distilled water, artificial saliva or citric acid at 37°C for 7 days. The uncoated and coated specimens (n=10) were then subjected to dynamic mechanical testing in flexure mode at 37°C with a frequency of 0.1 to 10Hz. Storage modulus, loss modulus and loss tangent data were subjected to normality testing and statistical analysis using one-way ANOVA/Scheffe's post-hoc test and Ttest at significance level p<0.05.
RESULTS: Mean storage modulus ranged from 1.39 ± 0.36 to 10.80 ± 0.86 GPa while mean loss modulus varied from 0.13 ± 0.03 to 0.70 ± 0.14 GPa after conditioning in the different mediums. Values for loss tangent ranged from 39.4 ± 7.75 to 213.2 ± 20.11 (x10 -3 ). Significant differences in visco-elastic properties were observed between mediums and materials. When conditioned in distilled water and artificial saliva,storage modulus was significantly improved when ZR, EQ and RV were uncoated. Significantly higher values were, however, observed with resin coating when the materials were exposed to citric acid.
CONCLUSION: The visco-elastic properties of HVGICs were influenced by both resin coating and chemical environment.

Matched MeSH terms: Viscosity
Dynamic analysis of bulk-fill composites: Effect of food-simulating liquids

Eweis AH, Yap AU, Yahya NA

J Mech Behav Biomed Mater, 2017 10;74:183-188.
PMID: 28605721 DOI: 10.1016/j.jmbbm.2017.06.004

This study investigated the effect of food simulating liquids on visco-elastic properties of bulk-fill restoratives using dynamic mechanical analysis. One conventional composite (Filtek Z350 [FZ]), two bulk-fill composites (Filtek Bulk-fill [FB] and Tetric N Ceram [TN]) and a bulk-fill giomer (Beautifil-Bulk Restorative [BB]) were evaluated. Specimens (12 × 2 × 2mm) were fabricated using customized stainless steel molds. The specimens were light-cured, removed from their molds, finished, measured and randomly divided into six groups. The groups (n = 10) were conditioned in the following mediums for 7 days at 37°C: air (control), artificial saliva (SAGF), distilled water, 0.02N citric acid, heptane, 50% ethanol-water solution. Specimens were assessed using dynamic mechanical testing in flexural three-point bending mode and their respective mediums at 37°C and a frequency range of 0.1-10Hz. The distance between the supports were fixed at 10mm and an axial load of 5N was employed. Data for elastic modulus, viscous modulus and loss tangent were subjected to ANOVA/Tukey's tests at significance level p < 0.05. Significant differences in visco-elastic properties were observed between materials and mediums. Apart from bulk-fill giomer, elastic modulus was the highest after conditioning in heptane. No apparent trends were noted for viscous modulus. Generally, loss tangent was the highest after conditioning in ethanol. The effect of food-simulating liquids on the visco-elastic properties of bulk-fill composites was material and medium dependent.

Matched MeSH terms: Viscosity
Effects of honey types and heating treatment on the textural, thermal, microstructural, and chemical properties of glutinous rice flour gels

Seow EK, Tan TC, Lee LK, Easa AM

J Texture Stud, 2020 12;51(6):909-916.
PMID: 32537814 DOI: 10.1111/jtxs.12544

Hardening issue in starch-based products that arises during storage, is ascribed to the long-term starch retrogradation which involves the recrystallisation of amylopectin. Present study aimed to delay storage hardening with the addition of high diastase honey bee honey (HBH) and low diastase kelulut bee honey (KBH) into glutinous rice flour (GRF) gels. As compared to KBH, retardation of texture deterioration by HBH was more prominent as evidenced by the significantly (p

Matched MeSH terms: Viscosity
Transesterification reaction for synthesis of palm-based ethylhexyl ester and formulation as base oil for synthetic drilling fluid

Abdul Habib NS, Yunus R, Rashid U, Taufiq-Yap YH, Abidin ZZ, Syam AM, et al.

J Oleo Sci, 2014;63(5):497-506.
PMID: 24717547

The use of vegetable oil-based ester as a base fluid in synthetic drilling fluid has become a trend in drilling operations due to its environmental advantages. The transesterification reaction of palm oil methyl ester (POME) with 2-ethylhexanol (2EH) produced 98% of palm oil-based ethylhexyl ester in less than 30 minutes. Since the transesterification reaction of POME with 2EH is a reversible reaction, its kinetics was studied in the presence of excess EH and under vacuum. The POME-to-EH molar ratio and vacuum pressure were held constant at 1:2 and 1.5 mbar respectively and the effects of temperature (70 to 110°C) were investigated. Using excess of EH and continual withdrawal of methanol via vacuum promoted the reaction to complete in less than 10 minutes. The rate constant of the reaction (k) obtained from the kinetics study was in the range of 0.44 to 0.66 s⁻¹ and the activation energy was 15.6 kJ.mol⁻¹. The preliminary investigations on the lubrication properties of drilling mud formulated with palm oil-based 2EH ester indicated that the base oil has a great potential to substitute the synthetic ester-based oil for drilling fluid. Its high kinematic viscosity provides better lubrication to the drilling fluid compared to other ester-based oils. The pour point (-15°C) and flash point (204°C) values are superior for the drilling fluid formulation. The plastic viscosity, HPHT filtrate loss and emulsion stability of the drilling fluid had given acceptable values, while gel strength and yield point could be improved by blending it with proper additives.

Matched MeSH terms: Viscosity
Fulltext Performance of Green Surfactants in the Formulation of Heavy-Duty Laundry Liquid Detergents (HDLD) with Special Emphasis on Palm Based Alpha Methyl Ester Sulfonates (α-MES)

Low SY, Tan JY, Ban ZH, Siwayanan P

J Oleo Sci, 2021 Aug 05;70(8):1027-1037.
PMID: 34248098 DOI: 10.5650/jos.ess21078

Liquid detergent has an increasing demand in North America, Western Europe, and Southeast Asia countries owing to its convenience to use and efficiency to clean. Alpha methyl ester sulfonates (α-MES), an anionic surfactant derived from palm oil based methyl ester, was reported to have lower manufacturing cost, good detergency with less dosage, excellent biodegradability, higher tolerance to hard water, and lower eco-toxicity as compared to linear alkylbenzene sulfonates (LABS). LABS was known as the workhorse of the detergent industry in the 20th century. Although palm-based α-MES was successfully used as the sole surfactant in powder detergent, there are still some unsettled technical issues related to phase stability and viscosity when using this anionic surfactant in heavy-duty laundry liquid detergent formulations. This paper will review not only the market overview of detergents, the application and performance of green surfactants in laundry detergents but also will highlight the technical issues related to the application of palm-based α-MES in laundry liquid detergent and some of the possible methods to overcome the formulation adversities.

Matched MeSH terms: Viscosity
Preparation, Stability and Thermal Characteristic of Al₂O₃/Bio-Oil Based Nanofluids for Heat Transfer Applications

Umar S, Sulaiman F, Abdullah N, Mohamad SN

J Nanosci Nanotechnol, 2020 12 01;20(12):7569-7576.
PMID: 32711628 DOI: 10.1166/jnn.2020.18616

Conventional thermal fluids with suspended nanoparticles, known as nanofluids, have been developed for heat transfer applications. Heat transfer loss could be reduced significantly if the thermophysical properties of the heat transfer fluid are improved, which to some extent, could reduce the present global environmental challenges associated with energy utilization, such as climate change and global warming. In this work, the role of the concentration of sodium dodecyl-benzene sulfonate (SDBS) in the stability of Al₂O₃/bio-oil nanofluid is investigated the zeta potential value, and its implications to the viscosity and thermal conductivity of the nanofluid are explored. The bio-oil based nanofluid is fixed using a two-step method in which the prepared base fluid is added with 13-nm alumina nanoparticles powder. Various weight fractions of SDBS (0.1, 0.2, 0.4, 0.6, and 1.0 wt%) are used for both 0.1 and 0.2 wt% Al₂O₃ to investigate the significance of the stability of a nanofluid on its thermal conductivity and viscosity. Results indicate that a stable nanofluid has reduced viscosity and increased thermal conductivity.

Matched MeSH terms: Viscosity
pH dependent poly[2-(methacryloyloxyethyl)trimetylammonium chloride-co-methacrylic acid]hydrogels for enhanced targeted delivery of 5-fluorouracil in colon cancer cells

Mishra RK, Ramasamy K, Ahmad NA, Eshak Z, Majeed AB

J Mater Sci Mater Med, 2014 Apr;25(4):999-1012.
PMID: 24398912 DOI: 10.1007/s10856-013-5132-x

Stimuli responsive hydrogels have shown enormous potential as a carrier for targeted drug delivery. In this study we have developed novel pH responsive hydrogels for the delivery of 5-fluorouracil (5-FU) in order to alleviate its antitumor activity while reducing its toxicity. We used 2-(methacryloyloxyethyl) trimetylammonium chloride a positively charged monomer and methacrylic acid for fabricating the pH responsive hydrogels. The released 5-FU from all except hydrogel (GEL-5) remained biologically active against human colon cancer cell lines [HT29 (IC50 = 110-190 μg ml(-1)) and HCT116 (IC50 = 210-390 μg ml(-1))] but not human skin fibroblast cells [BJ (CRL2522); IC50 ≥ 1000 μg ml(-1)]. This implies that the copolymer hydrogels (1-4) were able to release 5-FU effectively to colon cancer cells but not normal human skin fibroblast cells. This is probably due to the shorter doubling time that results in reduced pH in colon cancer cells when compared to fibroblast cells. These pH sensitive hydrogels showed well defined cell apoptosis in HCT116 cells through series of events such as chromatin condensation, membrane blebbing, and formation of apoptotic bodies. No cell killing was observed in the case of blank hydrogels. The results showed the potential of these stimuli responsive polymer hydrogels as a carrier for colon cancer delivery.

Matched MeSH terms: Viscosity
Novel chitosan derivative based composite scaffolds with enhanced angiogenesis; potential candidates for healing chronic non-healing wounds

Rizwan M, Yahya R, Hassan A, Yar M, Abd Halim AA, Rageh Al-Maleki A, et al.

J Mater Sci Mater Med, 2019 Jun 11;30(6):72.
PMID: 31187295 DOI: 10.1007/s10856-019-6273-3

The success of wound healing depends upon the proper growth of vascular system in time in the damaged tissues. Poor blood supply to wounded tissues or tissue engineered grafts leads to the failure of wound healing or rejection of grafts. In present paper, we report the synthesis of novel organosoluble and pro-angiogenic chitosan derivative (CSD) by the reaction of chitosan with 1,3-dimethylbarbituric acid and triethylorthoformate (TEOF). The synthesized material was characterized by FTIR and 13C-NMR to confirm the incorporated functional groups and new covalent connectivities. Biodegradability of the synthesized chitosan derivative was tested in the presence of lysozyme and was found to be comparable with CS. The cytotoxicity and apoptosis effect of new derivative was determined against gastric adenocarcinoma (AGS) cells and was found to be non-toxic. The CSD was found to be soluble in majority of organic solvents. It was blended with polycaprolactone (PCL) to form composite scaffolds. From an ex ovo CAM assay, it was noted that CSD stimulated the angiogenesis.

Matched MeSH terms: Viscosity
Application of diverse natural polymers in the design of oral gels for the treatment of periodontal diseases

Ganguly A, Ian CK, Sheshala R, Sahu PS, Al-Waeli H, Meka VS

J Mater Sci Mater Med, 2017 Mar;28(3):39.
PMID: 28144851 DOI: 10.1007/s10856-017-5852-4

The objective of this study was to prepare periodontal gels using natural polymers such as badam gum, karaya gum and chitosan. These gels were tested for their physical and biochemical properties and assessed for their antibacterial activity against Aggregatibacter actinomycetemcomitans and Streptococcus mutans, two pathogens associated with periodontal disease. Badam gum, karaya gum and chitosan were used to prepare gels of varying concentrations. Moxifloxacin hydrochloride, a known antimicrobial drug was choosen in the present study and it was added to the above gels. The gels were then run through a battery of tests in order to determine their physical properties such as pH and viscosity. Diffusion studies were carried out on the gels containing the drug. Antimicrobial testing of the gels against various bacteria was then carried out to determine the effectiveness of the gels against these pathogens. The results showed that natural polymers can be used to produce gels. These gels do not have inherent antimicrobial properties against A. actinomycetemcomitans and S. mutans. However, they can be used as a transport vehicle to carry and release antimicrobial drugs.

Matched MeSH terms: Viscosity
Investigation of the possibility of using waste cooking oil as a rejuvenating agent for aged bitumen

Zargar M, Ahmadinia E, Asli H, Karim MR

J Hazard Mater, 2012 Sep 30;233-234:254-8.
PMID: 22818590 DOI: 10.1016/j.jhazmat.2012.06.021

The ageing of the bitumen during storage, mixing, transport and laying on the road, as well as in service life, are the most important problems presented by the use of bitumen in pavements. This paper investigates the possibility of using waste cooking oil (WCO), which is a waste material that pollutes landfills and rivers, as an alternative natural rejuvenating agent for aged bitumen to a condition that resembles the original bitumen. With this target, the physical and chemical properties of the original bitumen, aged bitumen and rejuvenated bitumen were measured and compared by the bitumen binder tests - softening point, penetration, Brookfield viscosity, dynamic shear rheometer and Fourier transform infrared spectroscopy. In addition, the behaviour of the WCO rejuvenated bitumen is investigated and compared with virgin bitumen after using the rolling thin film oven ageing process. In general, the results showed that using 3-4% of WCO the aged bitumen group 40/50 was rejuvenated to a condition that closely resembled the physical, rheological properties of the original bitumen (80/100), however, there was a difference in the tendency to ageing between the WCO rejuvenated bitumen and the virgin bitumen during mixing, transport and laying on the road.

Matched MeSH terms: Viscosity
Effect of polymer concentration on the structure and performance of PEI hollow fiber membrane contactor for CO2 stripping

Naim R, Ismail AF

J Hazard Mater, 2013 Apr 15;250-251:354-61.
PMID: 23474409 DOI: 10.1016/j.jhazmat.2013.01.083

A series of polyetherimide (PEI) hollow fiber membranes with various polymer concentrations (13-16 wt.%) for CO2 stripping process in membrane contactor application was fabricated via wet phase inversion method. The PEI membranes were characterized in terms of liquid entry pressure, contact angle, gas permeation and morphology analysis. CO2 stripping performance was investigated via membrane contactor system in a stainless steel module with aqueous diethanolamine as liquid absorbent. The hollow fiber membranes showed decreasing patterns in gas permeation, contact angle, mean pore size and effective surface porosity with increasing polymer concentration. On the contrary, wetting pressure of PEI membranes has enhanced significantly with polymer concentration. Various polymer concentrations have different effects on the CO2 stripping flux in which membrane with 14 wt.% polymer concentration showed the highest stripping flux of 2.7 × 10(-2)mol/m(2)s. From the performance comparison with other commercial membrane, it is anticipated that the PEI membrane has a good prospect in CO2 stripping via membrane contactor.

Matched MeSH terms: Viscosity
Fulltext Effect of different pretreatments on functional properties of African catfish (Clarias gariepinus) skin gelatin

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

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