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Physicochemical characteristics of microbial content in a modified anaerobic inclining-baffled reactor (MAI-BR) treating recycled paper mill effluent (RPME)

Zwain HM, Chang SM, Dahlan I

Prep Biochem Biotechnol, 2019;49(4):344-351.
PMID: 30712465 DOI: 10.1080/10826068.2019.1566144

Microbial content formed in bioreactors plays a significant role in the anaerobic process. Therefore, the physicochemical characteristics of microbial content in a modified anaerobic inclining-baffled reactor (MAI-BR) treating recycled paper mill effluent (RPME) were investigated using Fourier transform infrared (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric (TG), and derivative thermogravimetric (DTG) analyses, scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), Brunauer-Emmett-Teller (BET), and surface area analyzer. FTIR spectra revealed that the microbial content had stronger characteristic peaks corresponding to alcohols, water, lipids carbohydrates, proteins, and mineral compounds. Calcite, muscovite, and lepidolite were the prevalent mineral phases found by XRD analysis. The elemental of these minerals like C, Ca, N, O, and Si was confirmed by XPS results. The microbial content samples from each compartment showed similar thermal behavior. SEM images showed that straight rod-shaped and Methanosaeta-like microorganisms were predominant, whereas C, O, and Ca were noticed by EDS on the surface of granules. The BET surface areas and pores of granules are found to decline throughout the reactor's compartment, where Compartment 1 had the largest values. Thus, the findings of this study establish further understanding of the physicochemical properties of microbial content formed in MAI-BR during the RPME treatment.

Matched MeSH terms: Aluminum Silicates
Fulltext Mechanical Properties of Longitudinal Basalt/Woven-Glass-Fiber-reinforced Unsaturated Polyester-Resin Hybrid Composites

Sapuan SM, Aulia HS, Ilyas RA, Atiqah A, Dele-Afolabi TT, Nurazzi MN, et al.

Polymers (Basel), 2020 Sep 27;12(10).
PMID: 32992450 DOI: 10.3390/polym12102211

This work represents a study to investigate the mechanical properties of longitudinal basalt/woven-glass-fiber-reinforced unsaturated polyester-resin hybrid composites. The hybridization of basalt and glass fiber enhanced the mechanical properties of hybrid composites. The unsaturated polyester resin (UP), basalt (B) and glass fibers (GF) were fabricated using the hand lay-up method in six formulations (UP, GF, B7.5/G22.5, B15/G15, B22.5/G7.5 and B) to produce the composites, respectively. This study showed that the addition of basalt to glass-fiber-reinforced unsaturated polyester resin increased its density, tensile and flexural properties. The tensile strength of the B22.5/G7.5 hybrid composites increased by 213.92 MPa compared to neat UP, which was 8.14 MPa. Scanning electron microscopy analysis was used to observe the fracture mode and fiber pullout of the hybrid composites.

Matched MeSH terms: Silicates
Fulltext Effects of Accelerated Weathering on Degradation Behavior of Basalt Fiber Reinforced Polymer Nanocomposites

Hashim UR, Jumahat A, Jawaid M, Dungani R, Alamery S

Polymers (Basel), 2020 Nov 06;12(11).
PMID: 33172162 DOI: 10.3390/polym12112621

This work aims to give insight on the effect of accelerated weathering, i.e., the combination of ultraviolet (UV) exposure and water spraying, on the visual and mechanical properties of basalt fiber reinforced polymer (BFRP) composites. The solvent exchange method, sonication and high shear milling technique were used to prepare the nanocomposite laminates. Three types of laminates were fabricated, i.e., unmodified BFRP, nanosilica modified BFRP and graphene nanoplatelet (GNP) modified BFRP composites with the total fiber loading of 45 wt.%. Glass fiber reinforced polymer (GFRP) laminate was also prepared for performance comparison purposes between the natural and synthetic fibers. The laminates were exposed to UV with a total weathering condition of 504 h using a Quantum-UV accelerated weathering tester. The weathering condition cycle was set at 8 h 60 °C UV exposure and 4 h 50 °C condensation. The discoloration visual inspection on the tested specimen was observed under the optical microscope. The obtained results showed that the UV exposure and water absorption caused severe discoloration of the laminates due to photo-oxidation reaction. The effect of weathering conditions on tensile and flexural properties of unmodified BFRP composites indicated that the UV exposure and water absorption caused reduction by 12% in tensile strength and by 7% in flexural strength. It is also found that the reduction in tensile and flexural properties of nanomodified BFRP composites was smaller than the unmodified system. It concluded from this work, that the mineral based composites (i.e., BFRP) has high potential for structural applications owing to its better properties than synthetic based composites (i.e., GFRP).

Matched MeSH terms: Silicates
Fulltext Chemical Sand Consolidation: From Polymers to Nanoparticles

Alakbari FS, Mohyaldinn ME, Muhsan AS, Hasan N, Ganat T

Polymers (Basel), 2020 May 07;12(5).
PMID: 32392770 DOI: 10.3390/polym12051069

The chemical sand consolidation methods involve pumping of chemical materials, like furan resin and silicate non-polymer materials into unconsolidated sandstone formations, in order to minimize sand production with the fluids produced from the hydrocarbon reservoirs. The injected chemical material, predominantly polymer, bonds sand grains together, lead to higher compressive strength of the rock. Hence, less amounts of sand particles are entrained in the produced fluids. However, the effect of this bonding may impose a negative impact on the formation productivity due to the reduction in rock permeability. Therefore, it is always essential to select a chemical material that can provide the highest possible compressive strength with minimum permeability reduction. This review article discusses the chemical materials used for sand consolidation and presents an in-depth evaluation between these materials to serve as a screening tool that can assist in the selection of chemical sand consolidation material, which in turn, helps optimize the sand control performance. The review paper also highlights the progressive improvement in chemical sand consolidation methods, from using different types of polymers to nanoparticles utilization, as well as track the impact of the improvement in sand consolidation efficiency and production performance. Based on this review, the nanoparticle-related martials are highly recommended to be applied as sand consolidation agents, due to their ability to generate acceptable rock strength with insignificant reduction in rock permeability.

Matched MeSH terms: Silicates
Fulltext Adsorption of DDT and PCB by Nanomaterials from Residual Soil

Taha MR, Mobasser S

PLoS One, 2015;10(12):e0144071.
PMID: 26659225 DOI: 10.1371/journal.pone.0144071

This paper presents the findings of a study on adsorption of dichlorodiphenythreechloroethen (DDT) and polychlorinated biphenyls (PCBs) on three nanomaterials including Multi walled Carbon Nanotube (MWNT), nano-clay and nano-alumina. DDT and PCBs are of significant concern due their high toxicity and long environmental half-lives. Experiments were conducted using batch adsorption procedures at different DDT and PCBs concentrations, from 10 to 60 mg/L. The amounts of MWNT, nano-clay and Nano-alumina used were 0.25%, 0.50%, 0.75%, 1%, 2% and 10%. The adsorption of PCBs solution onto the MWNT, nano-clay and nano-alumina was characterized by an initial rapid adsorption which eventually became constant within 22, 20, and 17 hours, respectively. The adsorption of DDT solution onto the MWNT, nano-clay and nano-alumina was also characterized by an initial rapid adsorption which gradually became constant within 22, 22 and 16 hours, respectively. Results of this study indicated that MWNT was a better adsorbent material compared to nano-clay and nano-alumina for both contaminants in this study. While at 10% of MWNT 88.9% and 77% of DDT and PCB were removed by MWNT, respectively. The effect of pH and temperature were also investigated.

Matched MeSH terms: Aluminum Silicates/chemistry
Fulltext Mechanical and in vitro biological performance of graphene nanoplatelets reinforced calcium silicate composite

Mehrali M, Moghaddam E, Seyed Shirazi SF, Baradaran S, Mehrali M, Latibari ST, et al.

PLoS One, 2014;9(9):e106802.
PMID: 25229540 DOI: 10.1371/journal.pone.0106802

Calcium silicate (CaSiO3, CS) ceramic composites reinforced with graphene nanoplatelets (GNP) were prepared using hot isostatic pressing (HIP) at 1150°C. Quantitative microstructural analysis suggests that GNP play a role in grain size and is responsible for the improved densification. Raman spectroscopy and scanning electron microscopy showed that GNP survived the harsh processing conditions of the selected HIP processing parameters. The uniform distribution of 1 wt.% GNP in the CS matrix, high densification and fine CS grain size help to improve the fracture toughness by ∼130%, hardness by ∼30% and brittleness index by ∼40% as compared to the CS matrix without GNP. The toughening mechanisms, such as crack bridging, pull-out, branching and deflection induced by GNP are observed and discussed. The GNP/CS composites exhibit good apatite-forming ability in the simulated body fluid (SBF). Our results indicate that the addition of GNP decreased pH value in SBF. Effect of addition of GNP on early adhesion and proliferation of human osteoblast cells (hFOB) was measured in vitro. The GNP/CS composites showed good biocompatibility and promoted cell viability and cell proliferation. The results indicated that the cell viability and proliferation are affected by time and concentration of GNP in the CS matrix.

Matched MeSH terms: Silicates/chemistry*
Fulltext Effect of Tricalcium Magnesium Silicate Coating on the Electrochemical and Biological Behavior of Ti-6Al-4V Alloys

Maleki-Ghaleh H, Hafezi M, Hadipour M, Nadernezhad A, Aghaie E, Behnamian Y, et al.

PLoS One, 2015;10(9):e0138454.
PMID: 26383641 DOI: 10.1371/journal.pone.0138454

In the current study, a sol-gel-synthesized tricalcium magnesium silicate powder was coated on Ti-6Al-4V alloys using plasma spray method. Composition of feed powder was evaluated by X-ray diffraction technique before and after the coating process. Scanning electron microscopy and atomic force microscopy were used to study the morphology of coated substrates. The corrosion behaviors of bare and coated Ti-6Al-4V alloys were examined using potentiodynamic polarization test and electrochemical impedance spectroscopy in stimulated body fluids. Moreover, bare and coated Ti-6Al-4V alloys were characterized in vitro by culturing osteoblast and mesenchymal stem cells for several days. Results demonstrated a meaningful improvement in the corrosion resistance of Ti-6Al-4V alloys coated with tricalcium magnesium silicate compared with the bare counterparts, by showing a decrease in corrosion current density from 1.84 μA/cm2 to 0.31 μA/cm2. Furthermore, the coating substantially improved the bioactivity of Ti-6Al-4Valloys. Our study on corrosion behavior and biological response of Ti-6Al-4V alloy coated by tricalcium magnesium silicate proved that the coating has considerably enhanced safety and applicability of Ti-6Al-4V alloys, suggesting its potential use in permanent implants and artificial joints.

Matched MeSH terms: Silicates/chemistry*
Fulltext Evaluation of stress distributions of calcium silicate-based root canal sealer in bulk or with main core material: A finite element analysis study

Smran A, Abdullah M, Ahmad NA, Ben Yahia F, Fouda AM, Alturaiki SA, et al.

PLoS One, 2024;19(3):e0299552.
PMID: 38483853 DOI: 10.1371/journal.pone.0299552

This research aimed to assess the stress distribution in lower premolars that were obturated with BioRoot RCS or AH Plus, with or without gutta percha (GP), and subjected to vertical and oblique forces. One 3D geometric model of a mandibular second premolar was created using SolidWorks software. Eight different scenarios representing different root canal filling techniques, single cone technique with GP and bulk technique with sealer only with occlusal load directions were simulated as follows: Model 1 (BioRoot RCS sealer and GP under vertical load [VL]), Model 2 (BioRoot RCS sealer and GP under oblique load [OL]), Model 3 (AH Plus sealer with GP under VL), Model 4 (AH Plus sealer with GP under OL), Model 5 (BioRoot RCS sealer in bulk under VL), Model 6 (BioRoot RCS in bulk under OL), Model 7 (AH Plus sealer in bulk under VL), and Model 8 (AH Plus sealer in bulk under OL). A static load of 200 N was applied at three occlusal contact points, with a 45° angle from lingual to buccal. The von Mises stresses in root dentin were higher in cases where AH Plus was used compared to BioRoot RCS. Furthermore, shifting the load to an oblique direction resulted in increased stress levels. Replacing GP with sealer material had no effect on the dentin maximum von Mises stress in BioRoot RCS cases. Presence of a core material resulted in lower stress in dentin for AH Plus cases, however, it did not affect the stress levels in dentin for cases filled with BioRoot RCS. Stress distribution in the dentin under oblique direction was higher regardless of sealer or technique used.

Matched MeSH terms: Silicates
Fulltext Green compression strength of tin mine tailing sand for green sand casting mould

Azhar Abdullah, Shamsuddin Sulaiman, Hang Tuah Baharudin, B.T., Mohd Khairol Anuar Mohd Ariffin, Vijayaram, Thoguluva Raghvan

Pertanika Journal of Science & Technology, 2013;21(2):335-342.
MyJurnal

Tailing sand is the residue mineral from tin extraction that contains between 94% and 99.5% silica, which can be used as moulding sand. It is found in abundance in the Kinta Valley in the state of Perak, Malaysia. Adequate water content and clay in moulding sand are important factors for better strength and
casting quality of products made from tailing sand. Samples of tailing sand were investigated according
to the American Foundrymen Society (AFS) standard. Cylindrical test pieces of Ø50 mm×50 mm in height from various sand-water ratios were compacted by applying three ramming blows of 6666g each using a Ridsdale-Dietert metric standard rammer. The specimens were tested for green compression strength using a Ridsdale-Dietert universal sand strength machine. Before the tests were conducted, moisture content of the tailing sand was measured using a moisture analyser. A mixture bonded with 8% clay possesses higher green compression strength compared to samples bonded with 4% clay. The results also show that in order to achieve maximum green compression strength, the optimum allowable moisture content for mixtures bonded with 8% clay is ranged between 3.75 and 6.5% and for mixtures bonded with 4% clay is 3-5.5%.

Matched MeSH terms: Aluminum Silicates
Fulltext UV-curable palm oil based-urethane acrylate/clay nanocomposites

Salih, A.M., Wan Md. Zin Wan Yunus, Khairul Zaman Mohd Dahlan, Mohd Hilmi Mahmood, Mansor Ahmad

Pertanika Journal of Science & Technology, 2012;20(2):435-444.
MyJurnal

Synthesis of palm oil based-urethane acrylate (POBUA) resins was carried out by acrylation of epoxidizedpalm oil (EPOP) using acrylic acid in the presence of a catalyst and followed by isocyanation to obtainthe POBUA. Using the monomer as a diluent in the formulation, 4% of photoinitiator and incorporationof organoclay (1-5% wt), nanocomposites were obtained upon UV irradiation. The X-ray DiffractoryXRD study revealed that the nanocomposites obtained were of the exfoliation type. The presence ofthe clay improved the hardness and did not affect the thermal stability. Similarly, it increased the glasstransition temperature Tg but reduced the modulus as the clay content was increased. The improvementof the tensile strength was only obtained when the clay concentration was 5 phr.

Matched MeSH terms: Aluminum Silicates
Fulltext Correlation of electrical resistivity with some soil parameters for the development of possible prediction of slope stability and bearing capacity of soil using electrical parameters

Syed Baharom Syed Osman, Mohammad Nabil Fikri, Fahad Irfan Siddique

Pertanika Journal of Science & Technology, 2014;22(1):139-152.
MyJurnal

The long term objective of this research is to look into the possibility of replacing soil strength parameters such as cohesion and angle of friction with electrical resistivity value for the purpose of computing among others, factor of safety in slopes or bearing capacity of soil. This paper however is limited to the investigation of correlation between electrical resistivity with some selected soil parameters. Electrical resistivity tests, using a basic multi meter, steel moulds and other related equipment, were conducted in the laboratory on soil samples with variations in soil type, compaction energy and moisture content. The samples consisted of predominantly clay, silt and sandy size particles and were compacted in a 100 x 100 mm square mould, while the corresponding electrical resistivity tests were carried out using the disc electrode method in accordance to BS 1377. The values of the electrical parameters such as voltage, current and resistance, with the corresponding value of soil parameters such as cohesion, angle of friction and moisture content, were measured and recorded. The results of the tests produced some initial crude relationships between electrical resistivity and the selected soil parameters. The strongest correlation between electrical resistivity and angle of internal friction, φ, was obtained from the clay size samples with R2 of 0.824, while the maximum correlation between electrical resistivity and moisture content again was obtained through the clay samples with R2 of 0.818. From the other results and graphs analyzed, some consistencies and specific trends of behaviour observed gave some early indications that a more detail and precise correlation between electrical resistivity and soil strength parameters could be very well possible in future.

Matched MeSH terms: Aluminum Silicates
Fulltext Distribution of Recent Ostracoda in offshore sediment of the South China Sea

Ramlan, O., Noraswana, N. F.

Pertanika Journal of Science & Technology, 2014;22(2):433-444.
MyJurnal

A study on the distribution of Recent Ostracoda in offshore sediment was carried out around the South China Sea. A total of 30 sediment samples were taken from the sampling stations between latitude 1°48’ and 7°25’N and longitude 102°09’ and 105°16’E. From this study, 79 species of ostracods belonging to 16 families and 44 genera were identified. The dominant species was Foveoleberis cypraeoides with 937 individuals obtained. There were 13 to 43 species in total. Diversity Index, H(s), was in the range of 2.1 to 3.3, whereas the dominance values were between 4.4 and 14.7%. Several environmental parameters were measured including depth, temperature and salinity. The range values for each of these parameters are 13-72 m, 25.24-30.06o C and 27.74-34.91 ppt, respectively. The sediment texture in this study area can be categorized as sand, sandy mud, clayey mud, silty mud, silty clay, clayey sand, clayey silt and silty sand. The observations revealed that abundance and diversity of ostracod appeared to be principally controlled by depth. Two faunal assemblages were identified in terms of faunal composition, namely, shallow water (Hemikrithe orientalis, Neomonoceratina iniqua, Stigmatocythere indica, Cytherelloidea leroyi and Neocytheretta snellii) and deep water (Paracypris sp., Alataconcha pterogona, Bythocytheropteron alatum, Keijella paucipunctata and Actinocythereis scutigera). A comparative analysis showed a high degree resemblance between the study area and south-eastern Malay Peninsula (the South China Sea).

Matched MeSH terms: Aluminum Silicates
Fulltext Relevance of integrated geophysical methods for site characterization in construction industry - a case of Apa in Badagry, Lagos State, Nigeria

Ishola, K. S., Adeoti, L., Sawyerr, F., Adiat, K. A. N

Pertanika Journal of Science & Technology, 2014;22(2):507-527.
MyJurnal

Detailed geophysical investigations have been carried out using integrated geophysical methods with a view to characterising the subsurface lithologic features that might indicate suitable places for structural developments. An overview of the subsurface resistivity distribution has been achieved employing 8Vertical Electrical Soundings with the Schlumberger array and 4 2D resistivity imaging using Wenner array. In order to constrain the results of the electrical resistivity methods, we carried out a ground magnetic survey along E-W direction using the Proton precession magnetometer at 1m sampling interval. Analysis of well logs data available and VES results showed 4 to 5 geoelectric layers corresponding to sand, clayey sand, clay, silty sand and sandy clay. The 2D resistivity imaging sections showed relative decrease of apparent resistivity with depth implying a geological transition from sand with high resistivity value of about 508Ωm to clay with low resistivity value 16Ωm at depths of 0-20m and 25-50m respectively. The magnetic profiles showed that the study area was characterised by short wavelengths and amplitudes ranging from –3800 to 700 nT. The highs and lows of the magnetic responses occasioned by lithological variations and structural features were magnetically resolved. In view of the identified subsurface structures, the suggested depth to the competent layer is about 20m for low to medium structures while above 50m would be suitable for heavy or massive engineering structures. The use of integrated geophysical methods for the delineation, identification and imaging of the subsurface geological structures which could provide clues to the nature and type of foundation suitable for the development of the study area has been successfully achieved.

Matched MeSH terms: Aluminum Silicates
Fulltext Characterisation of lateral and vertical subsurface heterogeneity in the ground using sustainable seismic surface wave methodology

Madun, A., Wijeyesekera, D.C., Ahmad Tajuddin, S.A., Zainalabidin, M.H., Yunus, R., Baharudin, M.F.

Pertanika Journal of Science & Technology, 2017;25(105):169-176.
MyJurnal

Seismic surface waves are a non-destructive technique used to obtain the dynamic properties of soil by measuring the shear wave velocity and calculating the shear modulus of soil. The shear modulus is one of the parameters to measure the stiffness of materials. This study evaluates soil profiles and the position of the sensor while conducting measurements of two , soil profiles, i.e. lateral and vertical non-homogeneities, using a continuous surface wave analysis (CSW) and multi-channel analysis of surface waves (MASW). Results showed the dispersive curve demonstrated an increased shear wave velocity with increasing depth for the sensor pair measurements on the clay (between columns), and decreased shear wave velocity with increasing depth for the sensor pair measurements on the column. In both instances the surface wave velocity results influenced by the depth and size of the wavelength, indicating that depth and wavelength controlled the volume of measurement in an elliptical shape. Therefore, the shear wave velocities and thus stiffness measured from the surface wave velocity techniques are represented the volume of soil measured across the sensor length.

Matched MeSH terms: Aluminum Silicates
Physicochemical, mechanical and biological properties of nano-calcium silicate-based cements: a systematic review

Majeed R, Elnawawy HM, Kutty MG, Yahya NA, Azami NH, Abu Kasim NH, et al.

Odontology, 2023 Oct;111(4):759-776.
PMID: 36864211 DOI: 10.1007/s10266-023-00786-0

This systematic review evaluated the effects of nano-sized cement particles on the properties of calcium silicate-based cements (CSCs). Using defined keywords, a literature search was conducted to identify studies that investigated properties of nano-calcium silicate-based cements (NCSCs). A total of 17 studies fulfilled the inclusion criteria. Results indicated that NCSC formulations have favourable physical (setting time, pH and solubility), mechanical (push out bond strength, compressive strength and indentation hardness) and biological (bone regeneration and foreign body reaction) properties compared with commonly used CSCs. However, the characterization and verification for the nano-particle size of NCSCs were deficient in some studies. Furthermore, the nanosizing was not limited to the cement particles and a number of additives were present. In conclusion, the evidence available for the properties of CSC particles in the nano-range is deficient-such properties could be a result of additives which may have enhanced the properties of the material.

Matched MeSH terms: Silicates/pharmacology
Fulltext Experimental Investigation and Simplistic Geochemical Modeling of CO₂ Mineral Carbonation Using the Mount Tawai Peridotite

Rahmani O, Highfield J, Junin R, Tyrer M, Pour AB

Molecules, 2016 Mar 16;21(3):353.
PMID: 26999082 DOI: 10.3390/molecules21030353

In this work, the potential of CO₂ mineral carbonation of brucite (Mg(OH)2) derived from the Mount Tawai peridotite (forsterite based (Mg)₂SiO4) to produce thermodynamically stable magnesium carbonate (MgCO3) was evaluated. The effect of three main factors (reaction temperature, particle size, and water vapor) were investigated in a sequence of experiments consisting of aqueous acid leaching, evaporation to dryness of the slurry mass, and then gas-solid carbonation under pressurized CO2. The maximum amount of Mg converted to MgCO₃ is ~99%, which occurred at temperatures between 150 and 175 °C. It was also found that the reduction of particle size range from >200 to <75 µm enhanced the leaching rate significantly. In addition, the results showed the essential role of water vapor in promoting effective carbonation. By increasing water vapor concentration from 5 to 10 vol %, the mineral carbonation rate increased by 30%. This work has also numerically modeled the process by which CO₂ gas may be sequestered, by reaction with forsterite in the presence of moisture. In both experimental analysis and geochemical modeling, the results showed that the reaction is favored and of high yield; going almost to completion (within about one year) with the bulk of the carbon partitioning into magnesite and that very little remains in solution.

Matched MeSH terms: Silicates/chemistry
Fulltext The Impact of Halloysite on the Thermo-Mechanical Properties of Polymer Composites

Gaaz TS, Sulong AB, Kadhum AAH, Al-Amiery AA, Nassir MH, Jaaz AH

Molecules, 2017 May 20;22(5).
PMID: 28531126 DOI: 10.3390/molecules22050838

Nanotubular clay minerals, composed of aluminosilicate naturally structured in layers known as halloysite nanotubes (HNTs), have a significant reinforcing impact on polymer matrixes. HNTs have broad applications in biomedical applications, the medicine sector, implant alloys with corrosion protection and manipulated transportation of medicines. In polymer engineering, different research studies utilize HNTs that exhibit a beneficial enhancement in the properties of polymer-based nanocomposites. The dispersion of HNTs is improved as a result of pre-treating HNTs with acids. The HNTs' percentage additive up to 7% shows the highest improvement of tensile strength. The degradation of the polymer can be also significantly improved by doping a low percentage of HNTs. Both the mechanical and thermal properties of polymers were remarkably improved when mixed with HNTs. The effects of HNTs on the mechanical and thermal properties of polymers, such as ultimate strength, elastic modulus, impact strength and thermal stability, are emphasized in this study.

Matched MeSH terms: Aluminum Silicates/chemistry*
Fulltext An in vitro Comparison of Bond Strength of Different Sealers/Obturation Systems to Root Dentin Using the Push-Out Test at 2 Weeks and 3 Months after Obturation

Yap WY, Che Ab Aziz ZA, Azami NH, Al-Haddad AY, Khan AA

Med Princ Pract, 2017;26(5):464-469.
PMID: 28934753 DOI: 10.1159/000481623

OBJECTIVE: To evaluate the push-out bond strength and failure modes of different sealers/obturation systems to intraradicular dentin at 2 weeks and 3 months after obturation compared to AH Plus®/gutta-percha.
MATERIALS AND METHODS: A total of 180 root slices from 60 single-canal anterior teeth were prepared and assigned to 5 experimental groups (n = 36 in each group), designated as G1 (AH Plus®/gutta-percha), G2 (TotalFill BC™ sealer/BC-coated gutta-percha), G3 (TotalFill BC™ sealer/gutta-percha), G4 (EndoREZ® sealer/EndoREZ®-coated gutta-percha), and G5 (EndoREZ® sealer/gutta-percha). Push-out bond strengths of 18 root slices in each group were assessed at 2 weeks and the other 18 at 3 months after obturation using a universal testing machine. Data were analyzed using repeated measures ANOVA. An independent t test was used to compare the mean push-out bond strength for each group at 2 weeks and 3 months after obturation.
RESULTS: The mean push-out bond strengths of G4 and G5 were significantly lower than those of G1, G2, and G3 (p < 0.05) at both 2 weeks (G1: 1.46 ± 0.29 MPa, G2: 1.74 ± 0.43 MPa, G3: 1.74 ± 0.43 MPa, G4: 0.66 ± 0.31 MPa, G5: 0.74 ± 0.47 MPa) and 3 months after obturation (G1: 1.70 ± 1.05 MPa, G2: 3.69 ± 1.20 MPa, G3: 2.84 ± 0.83 MPa, G4: 0.14 ± 0.05 MPa, G5: 0.24 ± 0.10 MPa). The mean push-out bond strengths of G2 (3.69 ± 1.20 MPa) and G3 (2.84 ± 0.83 MPa) were higher at 3 months compared to 2 weeks after obturation (G2: 1.74 ± 0.43 MPa, G3: 1.33 ± 0.29 MPa).
CONCLUSION: The TotalFill BC™ obturation system (G2) and the TotalFill BC™ sealer/gutta-percha (G3) showed comparable bond strength to AH Plus®. Their bond strength increased over time, whereas the EndoREZ® obturation system (G4) and EndoREZ sealer (G5) had low push-out bond strength which decreased over time.

Matched MeSH terms: Silicates/chemistry
Biomineralization, mechanical, antibacterial and biological investigation of larnite and rankinite bioceramics

Venkatraman SK, Choudhary R, Krishnamurithy G, Raghavendran HRB, Murali MR, Kamarul T, et al.

Mater Sci Eng C Mater Biol Appl, 2021 Jan;118:111466.
PMID: 33255048 DOI: 10.1016/j.msec.2020.111466

This work is aimed to develop a biocompatible, bactericidal and mechanically stable biomaterial to overcome the challenges associated with calcium phosphate bioceramics. The influence of chemical composition on synthesis temperature, bioactivity, antibacterial activity and mechanical stability of least explored calcium silicate bioceramics was studied. The current study also investigates the biomedical applications of rankinite (Ca3Si2O7) for the first time. Sol-gel combustion method was employed for their preparation using citric acid as a fuel. Differential thermal analysis indicated that the crystallization of larnite and rankinite occurred at 795 °C and 1000 °C respectively. The transformation of secondary phases into the desired product was confirmed by XRD and FT-IR. TEM micrographs showed the particle size of larnite in the range of 100-200 nm. The surface of the samples was entirely covered by the dominant apatite phase within one week of immersion. Moreover, the compressive strength of larnite and rankinite was found to be 143 MPa and 233 MPa even after 28 days of soaking in SBF. Both samples prevented the growth of clinical pathogens at a concentration of 2 mg/mL. Larnite and rankinite supported the adhesion, proliferation and osteogenic differentiation of hBMSCs. The variation in chemical composition was found to influence the properties of larnite and rankinite. The results observed in this work signify that these materials not only exhibit faster biomineralization ability, excellent cytocompatibility but also enhanced mechanical stability and antibacterial properties.

Matched MeSH terms: Silicates
Fulltext Development of Nano-SiO2 and Bentonite-Based Mortars for Corrosion Protection of Reinforcing Steel

Karunarathne VK, Paul SC, Šavija B

Materials (Basel), 2019 Aug 17;12(16).
PMID: 31426501 DOI: 10.3390/ma12162622

In this study, the use of nano-silica (nano-SiO2) and bentonite as mortar additives for combating reinforcement corrosion is reported. More specifically, these materials were used as additives in ordinary Portland cement (OPC)/fly ash blended mortars in different amounts. The effects of nano-silica and bentonite addition on compressive strength of mortars at different ages was tested. Accelerated corrosion testing was used to assess the corrosion resistance of reinforced mortar specimens containing different amounts of nano-silica and bentonite. It was found that the specimens containing nano-SiO2 not only had higher compressive strength, but also showed lower steel mass loss due to corrosion compared to reference specimens. However, this was accompanied by a small reduction in workability (for a constant water to binder ratio). Mortar mixtures with 4% of nano-silica were found to have optimal performance in terms of compressive strength and corrosion resistance. Control specimens (OPC/fly ash mortars without any additives) showed low early age strength and low corrosion resistance compared to specimens containing nano-SiO2 and bentonite. In addition, samples from selected mixtures were analyzed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Finally, the influence of Ca/Si ratio of the calcium silicate hydrate (C-S-H) in different specimens on the compressive strength is discussed. In general, the study showed that the addition of nano-silica (and to a lesser extent bentonite) can result in higher strength and corrosion resistance compared to control specimens. Furthermore, the addition of nano-SiO2 can be used to offset the negative effect of fly ash on early age strength development.

Matched MeSH terms: Silicates

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