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Comparative evaluation of three types of denture base materials with saliva substitute before and after thermocycling: An in vitro study

Jadhav V, Deshpande S, Radke U, Mahale H, Patil PG

J Prosthet Dent, 2021 Oct;126(4):590-594.
PMID: 33012529 DOI: 10.1016/j.prosdent.2020.07.014

STATEMENT OF PROBLEM: Xerostomia refers to the decrease in the quality and quantity of saliva. In denture wearers, xerostomia affects the retention of the denture because of lack of wettability of the denture base. However, which denture base resin materials are best wetted by artificial salivary substitutes is unclear.
PURPOSE: The purpose of this in vitro study was to determine the wetting properties of 3 different commercially available denture base resin materials with artificial salivary substitute by using contact angle measurements and to compare these properties before and after thermocycling.
MATERIAL AND METHODS: A total 120 specimens were fabricated with 3 different denture base materials (n=40): heat-polymerized polymethylmethacrylate (DenTek), injection-molded nylon polyamide (Valplast), and microwave polymerized (VIPI WAVE). The advancing and receding contact angles were measured with a goniometer by using the WinDrop++ software program. The contact angle hysteresis was calculated from the advancing and receding contact angles values. The same specimens were subjected to thermocycling to measure the advancing and receding contact angles values. The comparative evaluation was carried out before and after thermocycling.
RESULTS: The mean ±standard deviation contact angles of the microwave-polymerized material were (62.40 ±1.21 degrees) advancing contact angle, (32.12 ±0.66 degrees) receding contact angle, and (30.28 ±1.40 degrees) contact angle of hysteresis. It was followed by the injection-molded nylon polyamide material, whose mean ±standard deviation contact angle values were (68.57 ±1.72 degrees) advancing contact angle, (43.02 ±1.39 degrees) receding contact angle, (26.27 ±2.05 degrees) contact angle hysteresis and high impact strength heat-polymerized polymethylmethacrylate material, whose mean ±standard deviation contact angle values were (69.81 ±0.16 degrees) advancing contact angle, (41.90 ±1.02 degrees) receding contact angle, and (27.91 ±0.97 degrees) contact angle hysteresis. The statistical analysis showed significant differences among contact angle values of the microwave-polymerized material as compared with the heat-polymerized polymethylmethacrylate and injection-molded nylon polyamide materials (P

Matched MeSH terms: Wettability
Wettability of 3 different artificial saliva substitutes on heat-polymerized acrylic resin

Jaiswal N, Patil PG, Gangurde A, Parkhedkar RD

J Prosthet Dent, 2019 Mar;121(3):517-522.
PMID: 30391058 DOI: 10.1016/j.prosdent.2018.03.037

STATEMENT OF PROBLEM: The prosthodontic problems faced by a patient with xerostomia are of great concern. To aid in retention, artificial saliva substitutes should exhibit good wettability on the denture base.
PURPOSE: The purpose of this in vitro study was to evaluate the wettability of 3 different artificial saliva substitutes on heat-polymerized acrylic resin and to compare these properties with natural saliva and distilled water.
MATERIAL AND METHODS: A total of 150 heat-polymerized acrylic resin specimens were prepared with 25×15×2 mm dimensions. The specimens were divided into 5 groups (n=30): human saliva, distilled water, Aqwet, Mouth Kote, and Stoppers 4. The advancing and receding contact angle values were measured by using a goniometer, and the contact angle hysteresis and equilibrium angle were calculated. One-way ANOVA and the Bonferroni multiple comparisons test were performed to determine the difference between contact angle values among the groups (α=.05).
RESULTS: The means of the 5 groups differed significantly (P

Matched MeSH terms: Wettability
Fulltext Enhanced Evaporation Strength through Fast Water Permeation in Graphene-Oxide Deposition

Tong WL, Ong WJ, Chai SP, Tan MK, Hung YM

Sci Rep, 2015;5:11896.
PMID: 26100977 DOI: 10.1038/srep11896

The unique characteristic of fast water permeation in laminated graphene oxide (GO) sheets has facilitated the development of ultrathin and ultrafast nanofiltration membranes. Here we report the application of fast water permeation property of immersed GO deposition for enhancing the performance of a GO/water nanofluid charged two-phase closed thermosyphon (TPCT). By benchmarking its performance against a silver oxide/water nanofluid charged TPCT, the enhancement of evaporation strength is found to be essentially attributed to the fast water permeation property of GO deposition instead of the enhanced surface wettability of the deposited layer. The expansion of interlayer distance between the graphitic planes of GO deposited layer enables intercalation of bilayer water for fast water permeation. The capillary force attributed to the frictionless interaction between the atomically smooth, hydrophobic carbon structures and the well-ordered hydrogen bonds of water molecules is sufficiently strong to overcome the gravitational force. As a result, a thin water film is formed on the GO deposited layers, inducing filmwise evaporation which is more effective than its interfacial counterpart, appreciably enhanced the overall performance of TPCT. This study paves the way for a promising start of employing the fast water permeation property of GO in thermal applications.

Matched MeSH terms: Wettability
A study on the physical and hydraulic characteristics of cocopeat perlite mixture as a growing media in containerized plant production

Wan Fazilah Fazlil Ilahi, Desa Ahmad

Sains Malaysiana, 2016;46:975-980.

A well-known planting medium in soilless culture is a coconut based material famously known in Malaysia as cocopeat.
It is a viable ecologically friendly peat soil substitute for containerized crop production. The multipurpose growing media
had received much interest particularly in commercial applications. This study focused on the physical and hydraulic
characteristics of cocopeat perlite mixture as a growing media in containerized plant production. Perlite was added to
cocopeat at a ratio of 3 cocopeat: 1 perlite. Bulk density, particle density, porosity, particle size distribution, water holding
capacity, wettability and hydraulic conductivity of the media were evaluated. About 82.93% of the total particles were
in the range between 0.425 and 4 mm in diameter at a bulk density of 0.09 g/cm3
. Total porosity (79%) and wettability
improved with the incorporation of perlite to cocopeat. This study showed that water holding capacity was very high at
912.54% whereas the saturated hydraulic conductivity was low at 0.1 cm/s. The results showed that adding perlite to
cocopeat had improved the physical and hydraulic characteristics of the media.

Matched MeSH terms: Wettability
Dynamic mechanical and dielectric properties of modified surface chitosan/natural rubber latex

Taweepreda W

Sains Malaysiana, 2014;43:241-245.

Biodegradable polymeric films, obtained from chitosan/natural rubber latex (CS/NRL) blends with different compositions, have been prepared by wetting process. The blends were characterized by dynamic mechanical thermal analysis (DMTA) and found that the CS/NRL blends are thermodynamically incompatible. This is evident from the presence of two glass transitions, corresponding to CS and NRL phases in the blend. The mechanical properties of the CS/NRL blends were improved with increasing the amount of chitosan and after surface treatment with sulphuric acid due to the sulfonate ionic interaction. The dielectric properties was determined using Precision LCR meter in the frequency range 75 kHz up to 30 MHz. After CS/NRL surface treatment with sulphuric acid at high content of chitosan showed the highest dielectric constant. The surface properties of the CS/NRL blend films before and after surface treatment were confirmed by atomic force microscopy (AFM), respectively.

Matched MeSH terms: Wettability
Rainfall infiltration through unsaturated layered soil column

Aniza Ibrahim, Muhammad Mukhlisin, Othman Jaafar

Sains Malaysiana, 2014;43:1477-1484.

Infiltration caused by rainfall will lead to the changes of moisture content and soil pore water pressure or matric suction of the soil. These changes indicate the behavior of the soil especially during wetting and drying process. This paper presents the experimental test result of rain water infiltration into soil column for two samples of soils. The main objectives were to study the effect of rainfall intensity and duration of soil infiltration process for the forest soil and to compare its result to the gravelly sand. Infiltration experimental in this study involved three main components; water supply system, soil column and instrumentations, including percolation collection system. This study uses two types of tensiometers; 5 and 10 cm long. The results of TDR and tensiometers which were used to obtained moisture content and matric suction, respectively, shows that the system was successfully developed. For the forest soil, the result showed that moisture content of the top section is higher compared with the other sections. On the other hand, for gravelly sand, the moisture content in middle section is higher compared with the top and bottom section of the soil. Meanwhile, matric suction for both soils dropped during rainfall and gradually increases towards drying process. Other than that the comparison of soil matric suction between 5 and 10 cm tensiometers shows significant results for gravelly sand compared to forest soil.

Matched MeSH terms: Wettability
Dominant influence of the terminal molecule of PNIPA chain on wettability

Nurul Huda, Nahida Sultana, Mohd. Rashid

Sains Malaysiana, 2017;46:309-315.

Poly(N-isopropylacrylamide) (PNIPA) brushes on silicon substrate was constructed and molecular weight and polydispersity index was controlled precisely. Molecular behavior of the PNIPA grafted surface was observed by using captive bubble contact angle method. A very interesting phenomenon of high density PNIPA grafted membrane with a chloride terminal molecule was observed. The contact angle of high density PNIPA-Cl increased sharply while the temperature rises above 32oC. But in the case of PNIPA gel surface the contact angle result decreases sharply while the temperature reaches above lower critical solution temperature (LCST). In order to identify the reason behind this abnormal behavior of PNIPA-Cl grafted membrane, the terminal chloride molecule of PNIPA chain was modified to less electronegative azide (-N3) as well as carboxylic acid (-COOH). Finally it was found that terminal molecule of high density PNIPA grafted membrane has a great influences on the wettability change of PNIPA membrane in water by changing the temperature.

Matched MeSH terms: Wettability
Generation, characterization and application of atmospheric pressure plasma jet

Shrestha R, Subedi DP, Gurung JP, Wong CS

Sains Malaysiana, 2016;45:1689-1696.

The development of a non-thermal plasma jet with a capillary configuration working at atmospheric pressure is reported
in this paper. The plasma jet is powered by a power source with frequency of several kilohertz. The working gas is
argon. The plasma obtained has been characterized by optical emission spectroscopic measurements and electrical
measurements of the discharge using voltage and current probes. The electron temperature has been estimated by using
the modified Boltzmann plot method utilizing the Ar 4p-4s transition. The electron temperatures at various positions
along the plasma jet length have been obtained and it is found that the electron temperature decreases at position further
from orifice. The electron density has been estimated from current and voltage measurements using the power balance
method. The effects of gas flow rate, applied voltage and frequency on the characteristics of the plasma jet have also been
investigated. The applications of the atmospheric pressure plasma jet (APPJ) developed to modify the surface properties
of Polyethyleneterephthalate (PET) and polycarbonate (PC) have been tested. Our results showed that the atmospheric
pressure non-thermal plasma jet can be effectively used to enhance the surface wettability and surface energy of the
PET and PC. The plasma jet has also been tested for inactivation of prokaryotic cells (Escherichia coli, Staphylococcus
aureus). In the case of E. coli, better than 4 log10 reduction can be achieved. The effect of plasma jet on the pH of cell
culture medium has suggested that the plasma species, particularly the electrons, are solely responsible for the effect
of inactivation of living cells.

Matched MeSH terms: Wettability
Oleophilicity and oil-water separation by reduced graphene oxide grafted oil palm empty fruit bunch fibres

Mohd Shaiful Sajab, Wan Nurmawaddah Wan Abdul Rahman, Chin Hua Chia, Sarani Zakaria, Hatika Kaco, An’amt Mohamed Noor

Sains Malaysiana, 2018;47:1891-1896.

Absorption is one of the effective, simple and economical methods to remove oil from oily wastewater. The most widely
used approach is to utilize lignocellulosic biomass as oil absorbent. However, the hygroscopic of cellulose have limited
the oil-water separation capability of lignocellulosic fibers. In this study, the surface functionality of oil palm empty
fruit bunch (EFB) fibers was slightly altered by grafting reduced graphene oxide (rGO). The modified EFB fibers show
a distinct morphological and chemical characteristics changes as the surface of fibers has been coated with rGO. This
was supported by FTIR analysis with the diminishing peak of hydroxyl group region of EFB fibers. While the surface
modification on EFB fibers shows a diminution of a hydrophilic characteristic of 131.6% water absorption in comparison
with 268.9% of untreated EFB fibers. Moreover, modified fibers demonstrated an oil-water separation increment as well,
as it shows 89% of oil uptake and improved ~17 times of oil selectivity in oil-water emulsion than untreated EFB fibers.

Matched MeSH terms: Wettability
Surface modification via wet chemical etching of single-crystalline silicon for photovoltaic application

Reshak AH, Shahimin MM, Shaari S, Johan N

Prog Biophys Mol Biol, 2013 Nov;113(2):327-32.
PMID: 24139943 DOI: 10.1016/j.pbiomolbio.2013.10.002

The potential of solar cells have not been fully tapped due to the lack of energy conversion efficiency. There are three important mechanisms in producing high efficiency cells to harvest solar energy; reduction of light reflectance, enhancement of light trapping in the cell and increment of light absorption. The current work represent studies conducted in surface modification of single-crystalline silicon solar cells using wet chemical etching techniques. Two etching types are applied; alkaline etching (KOH:IPA:DI) and acidic etching (HF:HNO3:DI). The alkaline solution resulted in anisotropic profile that leads to the formation of inverted pyramids. While acidic solution formed circular craters along the front surface of silicon wafer. This surface modification will leads to the reduction of light reflectance via texturizing the surface and thereby increases the short circuit current and conversion rate of the solar cells.

Matched MeSH terms: Wettability
Fulltext Fabrication of Bio-Based Gelatin Sponge for Potential Use as A Functional Acellular Skin Substitute

Arif MMA, Fauzi MB, Nordin A, Hiraoka Y, Tabata Y, Yunus MHM

Polymers (Basel), 2020 Nov 13;12(11).
PMID: 33202700 DOI: 10.3390/polym12112678

Gelatin possesses biological properties that resemble native skin and can potentially be fabricated as a skin substitute for full-thickness wound treatment. The native property of gelatin, whereby it is easily melted and degraded at body temperature, could prevent its biofunctionality for various applications. This study aimed to fabricate and characterise buffalo gelatin (Infanca halal certified) crosslinked with chemical type crosslinker (genipin and genipin fortified with EDC) and physicaly crosslink using the dihydrothermal (DHT) method. A porous gelatin sponge (GS) was fabricated by a freeze-drying process followed by a complete crosslinking via chemical-natural and synthetic-or physical intervention using genipin (GNP), 1-ethyl-3-(3-dimethylaminopropyl) (EDC) and dihydrothermal (DHT) methods, respectively. The physicochemical, biomechanical, cellular biocompatibility and cell-biomaterial interaction of GS towards human epidermal keratinocytes (HEK) and dermal fibroblasts (HDF) were evaluated. Results showed that GS had a uniform porous structure with pore size ranging between 60 and 200 µm with high porosity (>78.6 ± 4.1%), high wettability (<72.2 ± 7.0°), high tensile strain (>13.65 ± 1.10%) and 14 h of degradation rate. An increase in the concentration and double-crosslinking approach demonstrated an increment in the crosslinking degree, enzymatic hydrolysis resistance, thermal stability, porosity, wettability and mechanical strength. The GS can be tuned differently from the control by approaching the GS via a different crosslinking strategy. However, a decreasing trend was observed in the pore size, water retention and water absorption ability. Crosslinking with DHT resulted in large pore sizes (85-300 µm) and low water retention (236.9 ± 18.7 g/m2·day) and a comparable swelling ratio with the control (89.6 ± 7.1%). Moreover no changes in the chemical content and amorphous phase identification were observed. The HEK and HDF revealed slight toxicity with double crosslinking. HEK and HDF attachment and proliferation remain similar to each crosslinking approach. Immunogenicity was observed to be higher in the double-crosslinking compared to the single-crosslinking intervention. The fabricated GS demonstrated a dynamic potential to be tailored according to wound types by manipulating the crosslinking intervention.

Matched MeSH terms: Wettability
Fulltext Thermal Stability and Water Content Study of Void-Free Electrospun SPEEK/Cloisite Membrane for Direct Methanol Fuel Cell Application

Awang N, Jaafar J, Ismail AF

Polymers (Basel), 2018 Feb 15;10(2).
PMID: 30966230 DOI: 10.3390/polym10020194

Void-free electrospun SPEEK/Cloisite15A® densed (SP/e-spunCL) membranes are prepared. Different loadings of Cloisite15A® (0.10, 0.15, 0.20, 0.25 and 0.30 wt %) are incorporated into electrospun fibers. The physico-chemical characteristics (methanol permeability, water uptake and proton conductivity) of the membranes are observed. Thermal stability of all membranes is observed using Thermal Gravimetry Analysis (TGA). The thrree stages of degradation range between 163.1 and 613.1 °C. Differential Scanning Calorimetry (DSC) is used to study the wettability of the membranes. SP/e-spunCL15 shows the lowest freezing bound water of 15.27%, which contributed to the lowest methanol permeability. The non-freezing bound water that proportionally increased with proton conductivity of SP/e-spunCL15 membrane is the highest, 10.60%. It is suggested that the electrospinning as the fabricating method has successfully exfoliated the Cloisite in the membrane surface structure, contributing to the decrease of methanol permeability, while the retained water has led to the enhancement of proton conductivity. This new fabrication method of SP/e-spunCL membrane is said to be a desirable polymer electrolyte membrane for future application in direct methanol fuel cell field.

Matched MeSH terms: Wettability
Fulltext Investigations on the Mechanical Properties of Glass Fiber/Sisal Fiber/Chitosan Reinforced Hybrid Polymer Sandwich Composite Scaffolds for Bone Fracture Fixation Applications

Arumugam S, Kandasamy J, Md Shah AU, Hameed Sultan MT, Safri SNA, Abdul Majid MS, et al.

Polymers (Basel), 2020 Jul 06;12(7).
PMID: 32640502 DOI: 10.3390/polym12071501

This study aims to explore the mechanical properties of hybrid glass fiber (GF)/sisal fiber (SF)/chitosan (CTS) composite material for orthopedic long bone plate applications. The GF/SF/CTS hybrid composite possesses a unique sandwich structure and comprises GF/CTS/epoxy as the external layers and SF/CTS/epoxy as the inner layers. The composite plate resembles the human bone structure (spongy internal cancellous matrix and rigid external cortical). The mechanical properties of the prepared hybrid sandwich composites samples were evaluated using tensile, flexural, micro hardness, and compression tests. The scanning electron microscopic (SEM) images were studied to analyze the failure mechanism of these composite samples. Besides, contact angle (CA) and water absorption tests were conducted using the sessile drop method to examine the wettability properties of the SF/CTS/epoxy and GF/SF/CTS/epoxy composites. Additionally, the porosity of the GF/SF/CTS composite scaffold samples were determined by using the ethanol infiltration method. The mechanical test results show that the GF/SF/CTS hybrid composites exhibit the bending strength of 343 MPa, ultimate tensile strength of 146 MPa, and compressive strength of 380 MPa with higher Young's modulus in the bending tests (21.56 GPa) compared to the tensile (6646 MPa) and compressive modulus (2046 MPa). Wettability study results reveal that the GF/SF/CTS composite scaffolds were hydrophobic (CA = 92.41° ± 1.71°) with less water absorption of 3.436% compared to the SF/CTS composites (6.953%). The SF/CTS composites show a hydrophilic character (CA = 54.28° ± 3.06°). The experimental tests prove that the GF/SF/CTS hybrid composite can be used for orthopedic bone fracture plate applications in future.

Matched MeSH terms: Wettability
Fulltext Isolation of Textile Waste Cellulose Nanofibrillated Fibre Reinforced in Polylactic Acid-Chitin Biodegradable Composite for Green Packaging Application

Rizal S, Olaiya FG, Saharudin NI, Abdullah CK, N G O, Mohamad Haafiz MK, et al.

Polymers (Basel), 2021 Jan 20;13(3).
PMID: 33498323 DOI: 10.3390/polym13030325

Textile waste cellulose nanofibrillated fibre has been reported with excellent strength reinforcement ability in other biopolymers. In this research cellulose nanofibrilated fibre (CNF) was isolated from the textile waste cotton fabrics with combined supercritical carbon dioxide and high-pressure homogenisation. The isolated CNF was used to enhance the polylactic acid/chitin (PLA/chitin) properties. The properties enhancement effect of the CNF was studied by characterising the PLA/chitin/CNF biocomposite for improved mechanical, thermal, and morphological properties. The tensile properties, impact strength, dynamic mechanical analysis, thermogravimetry analysis, scanning electron microscopy, and the PLA/chitin/CNF biocomposite wettability were studied. The result showed that the tensile strength, elongation, tensile modulus, and impact strength improved significantly with chitin and CNF compared with the neat PLA. Furthermore, the scanning electron microscopy SEM (Scanning Electron Microscopy) morphological images showed uniform distribution and dispersion of the three polymers in each other, which corroborate the improvement in mechanical properties. The biocomposite's water absorption increased more than the neat PLA, and the contact angle was reduced. The results of the ternary blend compared with PLA/chitin binary blend showed significant enhancement with CNF. This showed that the three polymers' combination resulted in a better material property than the binary blend.

Matched MeSH terms: Wettability
Fulltext Experimental evaluation of oil recovery mechanism using a variety of surface-modified silica nanoparticles: Role of in-situ surface-modification in oil-wet system

Adil M, Mohd Zaid H, Raza F, Agam MA

PLoS One, 2020;15(7):e0236837.
PMID: 32730369 DOI: 10.1371/journal.pone.0236837

Recent developments propose renewed use of surface-modified nanoparticles (NPs) for enhanced oil recovery (EOR) due to improved stability and reduced porous media retention. The enhanced surface properties render the nanoparticles more suitable compared to bare nanoparticles, for increasing the displacement efficiency of waterflooding. However, the EOR mechanisms using NPs are still not well established. This work investigates the effect of in-situ surface-modified silica nanoparticles (SiO2 NPs) on interfacial tension (IFT) and wettability behavior as a prevailing oil recovery mechanism. For this purpose, the nanoparticles have been synthesized via a one-step sol-gel method using surface-modification agents, including Triton X-100 (non-ionic surfactant) and polyethylene glycol (polymer), and characterized using various techniques. These results exhibit the well-defined spherical particles, particularly in the presence of Triton X-100 (TX-100), with particle diameter between 13 to 27 nm. To this end, SiO2 nanofluids were formed by dispersing nanoparticles (0.05 wt.%, 0.075 wt.%, 0.1 wt.%, and 0.2 wt.%) in 3 wt.% NaCl to study the impact of surface functionalization on the stability of the nanoparticle suspension. The optimal stability conditions were obtained at 0.1 wt.% SiO2 NPs at a basic pH of 10 and 9.5 for TX-100/ SiO2 and PEG/SiO nanofluids, respectively. Finally, the surface-treated SiO2 nanoparticles were found to change the wettability of treated (oil-wet) surface into water-wet by altering the contact angle from 130° to 78° (in case of TX-100/SiO2) measured against glass surface representing carbonate reservoir rock. IFT results also reveal that the surfactant treatment greatly reduced the oil-water IFT by 30%, compared to other applied NPs. These experimental results suggest that the use of surface-modified SiO2 nanoparticles could facilitate the displacement efficiency by reducing IFT and altering the wettability of carbonate reservoir towards water-wet, which is attributed to more homogeneity and better dispersion of surface-treated silica NPs compared to bare-silica NPs.

Matched MeSH terms: Wettability
Fulltext UV/O3 treatment as a surface modification of rice husk towards preparation of novel biocomposites

Rajendran Royan NR, Sulong AB, Yuhana NY, Chen RS, Ab Ghani MH, Ahmad S

PLoS One, 2018;13(5):e0197345.
PMID: 29847568 DOI: 10.1371/journal.pone.0197345

The use of rice husks (RH) to reinforce polymers in biocomposites are increasing tremendously. However, the incompatibility between the hydrophilic RH fibers and the hydrophobic thermoplastic matrices leads to unsatisfactory biocomposites. Surface modification of the fiber surface was carried out to improve the adhesion between fiber and matrix. In this study, the effect of surface modification of RH via alkali, acid and ultraviolet-ozonolysis (UV/O3) treatments on the properties of composites recycled high density polyethylene (rHDPE) composites was investigated. The untreated and treated RH were characterized by Fourier Transform Infrared (FTIR) and Scanning Electron Microscope (SEM). The composites containing 30 wt% of RH (treated and untreated) were then prepared via extrusion and followed by compression molding. As compared to untreated RH, all surface treated RH exhibited rougher surface and showed improved adhesion with rHDPE matrix. Tensile strength of UV/O3-treated RH composites showed an optimum result at 18.37 MPa which improved about 5% in comparison to the composites filled with untreated RH. UV/O3 treatment promotes shorter processing time and lesser raw material waste during treatment process where this is beneficial for commercialization in the future developments of wood plastic composites (WPCs). Therefore, UV/O3 treatment can be served as an alternative new method to modify RH surface in order to improve the adhesion between hydrophilic RH fibre and hydrophobic rHDPE polymer matrix.

Matched MeSH terms: Wettability
Fulltext Experimental study on electromagnetic-assisted ZnO nanofluid flooding for enhanced oil recovery (EOR)

Adil M, Lee K, Mohd Zaid H, Ahmad Latiff NR, Alnarabiji MS

PLoS One, 2018;13(2):e0193518.
PMID: 29489897 DOI: 10.1371/journal.pone.0193518

Recently, nano-EOR has emerged as a new frontier for improved and enhanced oil recovery (IOR & EOR). Despite their benefits, the nanoparticles tend to agglomerate at reservoir conditions which cause their detachment from the oil/water interface, and are consequently retained rather than transported through a porous medium. Dielectric nanoparticles including ZnO have been proposed to be a good replacement for EOR due to their high melting point and thermal properties. But more importantly, these particles can be polarized under electromagnetic (EM) irradiation, which provides an innovative smart Nano-EOR process denoted as EM-Assisted Nano-EOR. In this study, parameters involved in the oil recovery mechanism under EM waves, such as reducing mobility ratio, lowering interfacial tensions (IFT) and altering wettability were investigated. Two-phase displacement experiments were performed in sandpacks under the water-wet condition at 95°C, with permeability in the range of 265-300 mD. A crude oil from Tapis oil field was employed; while ZnO nanofluids of two different particle sizes (55.7 and 117.1 nm) were prepared using 0.1 wt. % nanoparticles that dispersed into brine (3 wt. % NaCl) along with SDBS as a dispersant. In each flooding scheme, three injection sequential scenarios have been conducted: (i) brine flooding as a secondary process, (ii) surfactant/nano/EM-assisted nano flooding, and (iii) second brine flooding to flush nanoparticles. Compare with surfactant flooding (2% original oil in place/OOIP) as tertiary recovery, nano flooding almost reaches 8.5-10.2% of OOIP. On the other hand, EM-assisted nano flooding provides an incremental oil recovery of approximately 9-10.4% of OOIP. By evaluating the contact angle and interfacial tension, it was established that the degree of IFT reduction plays a governing role in the oil displacement mechanism via nano-EOR, compare to mobility ratio. These results reveal a promising way to employ water-based ZnO nanofluid for enhanced oil recovery purposes at a relatively high reservoir temperature.

Matched MeSH terms: Wettability
Collapsibility and volume change behavior of unsaturated residual soil

Huat, Bujang B.K, Faisal AIi, Choong, Foong Heng

Pertanika Journal of Science & Technology, 2007;15(2):85-94.
MyJurnal

Residual soils occur in most countries of the world but the greater areas and depths are normally found in tropical humid areas. In these places, the soil forming processes are still very active and the weathering is much faster than the erosive factor. Most residual exhibit high soil suctions for most of the year. The absence of positive pore water pressure except immediately after rain, renders conventional soil mechanics for saturated soil irrelevant. In particular, the effective stress theories of saturated soil are not applicable at the practical leve l. Ignorance or lack of understanding of the geotechnical behavior of soil in the partially or unsaturated state has caused a lot of damages to infrastructures, buildings and other structures. For instances, the collapsibility and volume change of partially saturated soils in connection with the drying or wetting causes a lot of damage to foundation, roads and other structures. As such, the development of extended soil mechanics, which embraces the soil in the unsaturated state or subjected to soil suction, is essential. This paper examines the collapsibility and volume change behavior specifically of an unsaturated residual soil under various levels of applied matric suction (u -u ), and net mean stress (a-u) in a predetermined stress path. The volume change of ;he"' soil is found to be sensitive to both the applied matric suction and net mean stress. The soil is found to exhibit a collapsibility behavior upon a reduction in applied matric suction to 25 kPa at constant net mean stress.

Matched MeSH terms: Wettability
Fulltext Application of artificial neural networks for the optimisation of wetting contact angle for lead free Bi-Ag soldering alloys

Nima Ghamarian, Azmah Hanim, M.A., Nahavandi, M., Zulkarnain Zainal, Lim, Hong Ngee

Pertanika Journal of Science & Technology, 2017;25(4):1255-1260.
MyJurnal

In the recent years, electronic packaging provides significant research and development challenges
across multiple disciplines such as performance, materials, reliability, thermals and interconnections.
New technologies and techniques frequently adopted can be implemented in soldering alloys of
semiconductor sectors in terms of optimisation. Wetting contact angle or wettability of solder alloys
is one of the important factors which has got the attention of scholars. Hence in this study, due to the
remarkable similarity over classical solder alloys (Pb-Sn), Bi-Ag solder was investigated. Data were
collected through the effects of aging time variation and different weight percentages of Ag in solder
alloys. The contact angle of the alloys with Cu plate was measured by optical microscopy. Artificial
neural networks (ANNs) were applied on the measured datasets to develop a numerical model for further
simulation. Results of the experiments and simulations showed that the coefficient of determination (R2
)
is around 0.97, which signifies that the ANN set up is appropriate for the evaluation.

Matched MeSH terms: Wettability
Fulltext Role of Phase-Dependent Dielectric Properties of Alumina Nanoparticles in Electromagnetic-Assisted Enhanced Oil Recovery

Adil M, Lee KC, Zaid HM, Manaka T

Nanomaterials (Basel), 2020 Oct 06;10(10).
PMID: 33036153 DOI: 10.3390/nano10101975

The utilization of metal-oxide nanoparticles in enhanced oil recovery (EOR) has generated considerable research interest to increase the oil recovery. Among these nanoparticles, alumina nanoparticles (Al2O3-NPs) have proved promising in improving the oil recovery mechanism due to their prominent thermal properties. However, more significantly, these nanoparticles, coupled with electromagnetic (EM) waves, can be polarized to reduce water/oil mobility ratio and create disturbances at the oil/nanofluid interface, so that oil can be released from the reservoir rock surfaces and travelled easily to the production well. Moreover, alumina exists in various transition phases (γ, δ, θ, κ, β, η, χ), providing not only different sizes and morphologies but phase-dependent dielectric behavior at the applied EM frequencies. In this research, the oil recovery mechanism under EM fields of varying frequencies was investigated, which involved parameters such as mobility ratio, interfacial tension (IFT) and wettability. The displacement tests were conducted in water-wet sandpacks at 95 °C, by employing crude oil from Tapis. Alumina nanofluids (Al2O3-NFs) of four different phases (α, κ, θ and γ) and particle sizes (25-94.3 nm) were prepared by dispersing 0.01 wt. % NPs in brine (3 wt. % NaCl) together with SDBS as a dispersant. Three sequential injection scenarios were performed in each flooding scheme: (i) preflushes brine as a secondary flooding, (ii) conventional nano/EM-assisted nanofluid flooding, and (iii) postflushes brine to flush NPs. Compared to conventional nanofluid flooding (3.03-11.46% original oil in place/OOIP) as incremental oil recovery, EM-assisted nanofluid flooding provided an increase in oil recovery by approximately 4.12-12.90% of OOIP for different phases of alumina. It was established from these results that the recovery from EM-assisted nanofluid flooding is itself dependent on frequency, which is associated with good dielectric behavior of NPs to formulate the oil recovery mechanism including (i) mobility ratio improvement due to an electrorheological (ER) effect, (ii) interfacial disturbances by the oil droplet deformation, and (iii) wettability alteration by increased surface-free energy.

Matched MeSH terms: Wettability

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