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An efficient and economical treatment for batik textile wastewater containing high levels of silicate and organic pollutants using a sequential process of acidification, magnesium oxide, and palm shell-based activated carbon application

Birgani PM, Ranjbar N, Abdullah RC, Wong KT, Lee G, Ibrahim S, et al.

J Environ Manage, 2016 Dec 15;184(Pt 2):229-239.
PMID: 27717677 DOI: 10.1016/j.jenvman.2016.09.066

Considering the chemical properties of batik effluents, an efficient and economical treatment process was established to treat batik wastewater containing not only high levels of Si and chemical oxygen demand (COD), but also toxic heavy metals. After mixing the effluents obtained from the boiling and soaking steps in the batik process, acidification using concentrated hydrochloric acid (conc. HCl) was conducted to polymerize the silicate under acidic conditions. Consequently, sludge was produced and floated. XRD and FT-IR analyses showed that wax molecules were coordinated by hydrogen bonding with silica (SiO2). The acidification process removed ∼78-95% of COD and ∼45-50% of Si, depending on the pH. In the next stage, magnesium oxide (MgO) was applied to remove heavy metals completely and almost 90% of the Si in the liquid phase. During this step, about 70% of COD was removed in the hydrogel that arose as a consequence of the crosslinking characteristics of the formed nano-composite, such as magnesium silicate or montmorillonite. The hydrogel was composed mainly of waxes with polymeric properties. Then, the remaining Si (∼300 mg/L) in the wastewater combined with the effluents from the rinsing steps was further treated using 50 mg/L MgO. As a final step, palm-shell activated carbon (PSAC) was used to remove the remaining COD to

Matched MeSH terms: Silicates/chemistry
Kondogogu gum-Zn(+2)-pectinate emulgel matrices reinforced with mesoporous silica for intragastric furbiprofen delivery

Bera H, Nadimpalli J, Kumar S, Vengala P

Int J Biol Macromol, 2017 Nov;104(Pt A):1229-1237.
PMID: 28688948 DOI: 10.1016/j.ijbiomac.2017.07.027

Flurbiprofen (FLU), a non-steroidal anti-inflammatory drug, exhibits limited clinical response due to its poor physicochemical properties. This study aimed at developing reliable drug carriers for intrgastric FLU delivery with a view to improve biopharmaceutical characteristics of drug and modulate its release in a controlled manner. In this context, FLU-loaded kondogogu gum (KG)-Zn(+2)-low methoxyl (LM) pectinate emulgel matrices reinforced with calcium silicate (CS) were accomplished by ionotropic gelation technique employing zinc acetate as cross-linker and characterized for their in vitro performances. All the formulations demonstrated excellent drug encapsulation efficiency (DEE, 46-87%) and sustained drug release behavior (Q7h, 70-91%). These quality attributes were remarkably influenced by polymer-blend (LM pectin:KG) ratios, low-density oil types and CS inclusion. The drug release profile of the FLU-loaded optimized matrices (F-7) was best fitted in Korsmeyer-Peppas model with Fickian diffusion driven mechanism. It also conferred excellent in vitro gastroretention capabilities. Moreover, the drug-excipient compatibility, alteration of crystallinity and thermal behavior of drug and surface morphology of matrices were evidenced with the results of FTIR, XRD, DSC and SEM analyses, respectively. Thus, the newly developed matrices are appropriate for sustained intragastric FLU delivery and simultaneous zinc supplementation for effective inflammation and arthritis management.

Matched MeSH terms: Silicates
Carboxymethyl fenugreek galactomannan-gellan gum-calcium silicate composite beads for glimepiride delivery

Bera H, Mothe S, Maiti S, Vanga S

Int J Biol Macromol, 2018 Feb;107(Pt A):604-614.
PMID: 28916379 DOI: 10.1016/j.ijbiomac.2017.09.027

Novel carboxymethyl fenugreek galactomannan (CFG)-gellan gum (GG)-calcium silicate (CS) composite beads were developed for controlled glimepiride (GLI) delivery. CFG having degree of carboxymethylation of 0.71 was synthesized and characterized by FTIR, DSC and XRD analyses. Subsequently, GLI-loaded hybrids were accomplished by ionotropic gelation technique employing Ca+2/Zn+2/Al+3 ions as cross-linkers. All the formulations demonstrated excellent drug encapsulation efficiency (DEE, 48-97%) and sustained drug release behaviour (Q8h, 62-94%). These quality attributes were remarkably influenced by polymer-blend (GG:CFG) ratios, cross-linker types and CS inclusion. The drug release profile of the optimized formulation (F-6) was best fitted in zero-order model with anomalous diffusion driven mechanism. It also conferred excellent ex vivo mucoadhesive property and considerable hypoglycemic effect in streptozotocin-induced diabetic rats. Furthermore, the beads were characterized for drug-excipients compatibility, drug crystallinity, thermal behaviour and surface morphology. Thus, the developed hybrid matrices are appropriate for controlled delivery of GLI for Type 2 diabetes management.

Matched MeSH terms: Silicates/chemistry
Perlakuan Beberapa Unsur Major dan Unsur Surih dalam Profil Luluhawa Batuan Basalt di Segamat Johor

Baba Musta, Mohamad Md. Tan

Sains Malaysiana, 1996;25.

Highly weathered basaltic rock was exposed at PSK profile of Kuantan, Segamat Highway. The weathering profile from fresh rock soil can be observed at PKJ profile at Kg. Jabi Quarry. Twelve rock and soil samples from PSK profile and thirteen samples from PKJ profile have been collected for geochemical analysis. The objective of the analysis is to establish the behaviour of several major and trace elements in the weathering profile of the basaltic rock. The samples were analysed by XRF and XRD techniques. Petrographic study was done on fresh rock samples and concretions. The concentration of major elements (TiO2, Al2O3 and Fe2O3) appear to be increased with the increasing of the degree of weathering whereas the concentration of SiO2 and CaO are decreased. There is a clear correlation between Fe2O3 + Al2O3 with L.O.I as well as between Fe2O3 with Al2O3. Behaviour of the trace elements (Ni, Co, Cr and Zn) against the weathering process are totally different. The secondary minerals (kaolinite, nactire, geothite, hematite and gibbsite) appear to control the behaviour of the major and trace elements.
Batuan basalt yang terluluhawa sepenuhnya telah dicerap di lokaliti PSK Lebuhraya Segamat-Kuantan. Profil luluhawa yang boleh dilihat perubahan daripada batuan segar hingga tanih didapati di lokaliti PKJ Kuari Kg. Jabi. Dua contoh profil dengan masing-masing 12 sampel dan 13 sample tanih telah dikaji untuk menentukan perlakuan beberapa unsur major dan unsur surih batuan basalt yang terluluhawa. Kaedah analisis yang digunakan ialah pendarflour sinar-X (XRF) dan pembelauan sinar-X (XRF). Kajian petrografi pula dibuat pada sampel batuan segar dan sampel konkresi. Nilai unsur major TiO2, Al2O3 dan Fe2O3 bertambah dengan bertambahnya darjah luluhawa manakala SiO2 dan CaO menyusut. Hubungan korelasi Fe2O3 + Al2O3 dengan L.O.I dan Fe2O3 denagn Al2O3 adalah jelas. Unsur surih nikel (Ni) kobalt (Co), kromium (Cr) dan zink (Zn) mempunyai perlakuan yang berbeza-beza dengan luluhawa. Perlakuan yang ditunjukkan oleh unsur major dan surih tersebut dikawal oleh mineral sekunder (koalinit, nakrit, geotit, hematit dan gibsit).

Matched MeSH terms: Silicates
Fulltext Strength Development and Elemental Distribution of Dolomite/Fly Ash Geopolymer Composite under Elevated Temperature

Azimi EA, Abdullah MMAB, Vizureanu P, Salleh MAAM, Sandu AV, Chaiprapa J, et al.

Materials (Basel), 2020 Feb 24;13(4).
PMID: 32102345 DOI: 10.3390/ma13041015

A geopolymer has been reckoned as a rising technology with huge potential for application across the globe. Dolomite refers to a material that can be used raw in producing geopolymers. Nevertheless, dolomite has slow strength development due to its low reactivity as a geopolymer. In this study, dolomite/fly ash (DFA) geopolymer composites were produced with dolomite, fly ash, sodium hydroxide, and liquid sodium silicate. A compression test was carried out on DFA geopolymers to determine the strength of the composite, while a synchrotron Micro-Xray Fluorescence (Micro-XRF) test was performed to assess the elemental distribution in the geopolymer composite. The temperature applied in this study generated promising properties of DFA geopolymers, especially in strength, which displayed increments up to 74.48 MPa as the optimum value. Heat seemed to enhance the strength development of DFA geopolymer composites. The elemental distribution analysis revealed exceptional outcomes for the composites, particularly exposure up to 400 °C, which signified the homogeneity of the DFA composites. Temperatures exceeding 400 °C accelerated the strength development, thus increasing the strength of the DFA composites. This appears to be unique because the strength of ordinary Portland Cement (OPC) and other geopolymers composed of other raw materials is typically either maintained or decreases due to increased heat.

Matched MeSH terms: Silicates
The Intragranular Textures of Aggregates and its Correlation to the Physical Properties

Azimah Hussain, Poole C

Sains Malaysiana, 2010;39.

To evaluate the correlation of the intragranular textures on the physical properties of coarse aggregates, four aggregates samples consisting of three granitoid sources and one limestone have been studied. The role played by intragranular textures (mineral assembladge, grain size and grain boundaries) in influencing the physical properties are potentially significant to the fact that such textural variation may complicate the aggregate strength. This study indicates that the aggregates exhibited variation in textural habits. The granitoid aggregates, which is rich with silicate composition has typical heterogranular textures of porphyritic and equigranular grain structures. Whereas the limestone aggregate comprises of bioclast and peloid allochems cemented by micrite and spar. The granitoid aggregates showed better dispersed characters and had extremely interlocking crystal boundaries which have more physical strength compared to a carbonate aggregate.

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 Marine electrical imaging reveals novel freshwater transport mechanism in Hawai'i

Attias E, Thomas D, Sherman D, Ismail K, Constable S

Sci Adv, 2020 Nov;6(48).
PMID: 33239299 DOI: 10.1126/sciadv.abd4866

Conventional hydrogeologic framework models used to compute ocean island sustainable yields and aquifer storage neglect the complexity of the nearshore and offshore submarine environment. However, the onshore aquifer at the island of Hawai'i exhibits a notable volumetric discrepancy between high-elevation freshwater recharge and coastal discharge. In this study, we present a novel transport mechanism of freshwater moving from onshore to offshore through a multilayer formation of water-saturated layered basalts with interbedded low-permeability layers of ash/soil. Marine electromagnetic imaging reveals ∼35 km of laterally continuous resistive layers that extend to at least 4 km from west of Hawai'i's coastline, containing about 3.5 km3 of freshened water. We propose that this newly found transport mechanism of fresh groundwater may be the governing mechanism in other volcanic islands. In such a scenario, volcanic islands worldwide can use these renewable offshore reservoirs, considered more resilient to climate change-driven droughts, as new water resources.

Matched MeSH terms: Silicates
Fulltext A comparison in mechanical properties of cermets of calcium silicate with Ti-55Ni and Ti-6Al-4V alloys for hard tissues replacement

Ataollahi Oshkour A, Pramanik S, Shirazi SF, Mehrali M, Yau YH, Abu Osman NA

ScientificWorldJournal, 2014;2014:616804.
PMID: 25538954 DOI: 10.1155/2014/616804

This study investigated the impact of calcium silicate (CS) content on composition, compressive mechanical properties, and hardness of CS cermets with Ti-55Ni and Ti-6Al-4V alloys sintered at 1200°C. The powder metallurgy route was exploited to prepare the cermets. New phases of materials of Ni16Ti6Si7, CaTiO3, and Ni31Si12 appeared in cermet of Ti-55Ni with CS and in cermet of Ti-6Al-4V with CS, the new phases Ti5Si3, Ti2O, and CaTiO3, which were emerged during sintering at different CS content (wt%). The minimum shrinkage and density were observed in both groups of cermets for the 50 and 100 wt% CS content, respectively. The cermets with 40 wt% of CS had minimum compressive Young's modulus. The minimum of compressive strength and strain percentage at maximum load were revealed in cermets with 50 and 40 wt% of CS with Ti-55Ni and Ti-6Al-4V cermets, respectively. The cermets with 80 and 90 wt% of CS showed more plasticity than the pure CS. It concluded that the composition and mechanical properties of sintered cermets of Ti-55Ni and Ti-6Al-4V with CS significantly depend on the CS content in raw cermet materials. Thus, the different mechanical properties of the cermets can be used as potential materials for different hard tissues replacements.

Matched MeSH terms: Silicates/chemistry*
Mechanical and physical behavior of newly developed functionally graded materials and composites of stainless steel 316L with calcium silicate and hydroxyapatite

Ataollahi Oshkour A, Pramanik S, Mehrali M, Yau YH, Tarlochan F, Abu Osman NA

J Mech Behav Biomed Mater, 2015 Sep;49:321-31.
PMID: 26072197 DOI: 10.1016/j.jmbbm.2015.05.020

This study aimed to investigate the structural, physical and mechanical behavior of composites and functionally graded materials (FGMs) made of stainless steel (SS-316L)/hydroxyapatite (HA) and SS-316L/calcium silicate (CS) employing powder metallurgical solid state sintering. The structural analysis using X-ray diffraction showed that the sintering at high temperature led to the reaction between compounds of the SS-316L and HA, while SS-316L and CS remained intact during the sintering process in composites of SS-316L/CS. A dimensional expansion was found in the composites made of 40 and 50 wt% HA. The minimum shrinkage was emerged in 50 wt% CS composite, while the maximum shrinkage was revealed in samples with pure SS-316L, HA and CS. Compressive mechanical properties of SS-316L/HA decreased sharply with increasing of HA content up to 20 wt% and gradually with CS content up to 50 wt% for SS-316L/CS composites. The mechanical properties of the FGM of SS-316L/HA dropped with increase in temperature, while it was improved for the FGM of SS-316L/CS with temperature enhancement. It has been found that the FGMs emerged a better compressive mechanical properties compared to both the composite systems. Therefore, the SS-316L/CS composites and their FGMs have superior compressive mechanical properties to the SS-316L/HA composites and their FGMs and also the newly developed FGMs of SS-316L/CS with improved mechanical and enhanced gradation in physical and structural properties can potentially be utilized in the components with load-bearing application.

Matched MeSH terms: Silicates/chemistry*
Fulltext Sustainable Production of Arecanut Husk Ash as Potential Silica Replacement for Synthesis of Silicate-Based Glass-Ceramics Materials

Anuar MF, Fen YW, Azizan MZ, Rahmat F, Mohd Zaid MH, Khaidir REM, et al.

Materials (Basel), 2021 Feb 28;14(5).
PMID: 33670923 DOI: 10.3390/ma14051141

Arecanut husk (AH) was selected as a material for silica replacement in the synthesis process of glass-ceramics zinc silicate and also the fact that it has no traditional use and often being dumped and results in environmental issues. The process of pyrolysis was carried out at temperature 700 °C and above based on thermogravimetric analysis to produce arecanut husk ash (AHA). The average purity of the silica content in AHA ranged from 29.17% to 45.43%. Furthermore, zinc oxide was introduced to AHA and zinc silicate started to form at sintering temperature 700 °C and showed increased diffraction intensity upon higher sintering temperature of 600 °C to 1000 °C based on X-ray diffraction (XRD) analysis. The grain sizes of the zinc silicate increased from 1011 nm to 3518 nm based on the morphological studies carried out by field emission scanning electron microscopy (FESEM). In addition, the optical band gap of the sample was measured to be in the range from 2.410 eV to 2.697 eV after sintering temperature. From the data, it is believed that a cleaner production of low-cost zinc silicate can be achieved by using arecanut husk and have the potential to be used as phosphors materials.

Matched MeSH terms: Silicates
Penentuan Isotop Uranium dan Torium dalam Monazit, Xenotim dan Zirkon Menggunakan Spektrometri Alfa

Amran B. Ab. Majid, Mohd Zahari Abdullah, Zaharuddin Ahmad

Sains Malaysiana, 1996;25.

The determination technique for U (238U, 235U, 234U) and Th (232Th, 230Th, 228Th) isotopes using alpha spectrometry was developed. The developed technique involved digestion, dissolution, coprecipitation, solvent extraction and electrodeposition methods. The NBS River Sediment and Rocky Flats Soil Standard Reference Materials were analysed to determine the accuracy of the technique. A good accuracy and high percentage recovery of the carrier (70 - 90%) indicated that the developed technique was suitable for U and Th isotopes determination. The technique was used to determine the U and Th concentration in monazite, xenotime and zircon samples. The results showed that the U and Th total concentrations were in the range of 21.03 to 171.25 Bq/g and 27.48 to 242.87 Bq/g respectively.
Kaedah penguraian, pemelarutan, pemendakan bersama, ekstraksi pelarut dan pemendapan elektrik telah dikaji dan digunakan untuk mendapatkan suatu teknik yang terbaik dalam penentuan isotop uranium 234U, 235U & 238U) dan torium 228Th, 230Th & 232Th) menggunakan sistem spektrometri alfa. Kepekatan isotop U dan Th dalam bahan rujukan piawai River Sediment dan Rocky Flats Soil (NBS) telah dianalisis untuk menentukan kejituan teknik yang dibangunkan. Kajian ini mendapati kepekatan isotop yang diperolehi adalah menghampiri nilai teraku (sijil) dan peratus perolehan semula pembawa yang besar (70-90%). Ini menunjukkan teknik yang dibangunkan sesuai digunakan untuk penentuan isotop uranium dan torium. Seterusnya teknik yang dibangunkan telah digunakan untuk menentukan kandungan uranium dan torium dalam sampel monazit, xenotim dan zirkon tempatan. Kepekatan jumlah isotop uranium yang diperolehi didapati berada dalam julat 21.03 - 171.25 Bq/g manakala kepekatan jumlah isotop torium pula terletak antara 27.48 - 242.87 Bq/g.

Matched MeSH terms: Silicates
Fulltext Influence of organic molecules on wetting characteristics of mica/H2/brine systems: Implications for hydrogen structural trapping capacities

Ali M, Yekeen N, Pal N, Keshavarz A, Iglauer S, Hoteit H

J Colloid Interface Sci, 2022 Feb 15;608(Pt 2):1739-1749.
PMID: 34742087 DOI: 10.1016/j.jcis.2021.10.080

HYPOTHESIS: Actualization of the hydrogen (H2) economy and decarbonization goals can be achieved with feasible large-scale H2 geo-storage. Geological formations are heterogeneous, and their wetting characteristics play a crucial role in the presence of H2, which controls the pore-scale distribution of the fluids and sealing capacities of caprocks. Organic acids are readily available in geo-storage formations in minute quantities, but they highly tend to increase the hydrophobicity of storage formations. However, there is a paucity of data on the effects of organic acid concentrations and types on the H2-wettability of caprock-representative minerals and their attendant structural trapping capacities.
EXPERIMENT: Geological formations contain organic acids in minute concentrations, with the alkyl chain length ranging from C4 to C26. To fully understand the wetting characteristics of H2 in a natural geological picture, we aged mica mineral surfaces as a representative of the caprock in varying concentrations of organic molecules (with varying numbers of carbon atoms, lignoceric acid C24, lauric acid C12, and hexanoic acid C6) for 7 days. To comprehend the wettability of the mica/H2/brine system, we employed a contact-angle procedure similar to that in natural geo-storage environments (25, 15, and 0.1 MPa and 323 K).
FINDINGS: At the highest investigated pressure (25 MPa) and the highest concentration of lignoceric acid (10-2 mol/L), the mica surface became completely H2 wet with advancing (θa= 106.2°) and receding (θr=97.3°) contact angles. The order of increasing θa and θr with increasing organic acid contaminations is as follows: lignoceric acid > lauric acid > hexanoic acid. The results suggest that H2 gas leakage through the caprock is possible in the presence of organic acids at higher physio-thermal conditions. The influence of organic contamination inherent at realistic geo-storage conditions should be considered to avoid the overprediction of structural trapping capacities and H2 containment security.

Matched MeSH terms: Aluminum 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
Effect of aging on coronal microleakage in access cavities through metal ceramic crowns restored with resin composites

Al-Maqtari AA, Lui JL

J Prosthodont, 2010 Jul;19(5):347-56.
PMID: 20456026 DOI: 10.1111/j.1532-849X.2010.00593.x

The purpose of this in vitro study was to determine if packable resin composite with/without flowable resin composite has the ability to prevent coronal leakage in restored endodontic access openings following aging.

Matched MeSH terms: Aluminum Silicates/chemistry
Effect of Intracanal Medicaments on the Bond Strength of Bioceramic Root Filling Materials to Oval Canals

Al-Haddad AY, Kacharaju KR, Haw LY, Yee TC, Rajantheran K, Mun CS, et al.

J Contemp Dent Pract, 2020 Nov 01;21(11):1218-1221.
PMID: 33850066

AIM: This study aimed to evaluate the effect of the prior application of intracanal medicaments on the bond strength of OrthoMTA (mineral trioxide aggregate) and iRoot SP to the root dentin.
MATERIALS AND METHODS: Thirty single-rooted mandibular premolars were standardized and prepared using ProTaper rotary files. The specimens were divided into a control group and two experimental groups receiving Diapex and Odontopaste medicament, either filled with iRoot SP or OrthoMTA, for 1 week. Each root was sectioned transversally, and the push-out bond strength and failure modes were evaluated. The data were analyzed using Kruskal Wallis and Mann-Whitney U post hoc test.
RESULTS: There was no significant difference between the bond strength of iRoot SP and OrthoMTA without medicaments and with the prior placement of Diapex (p value > 0.05). However, iRoot SP showed significantly higher bond strength with the prior placement of Odontopaste (p value < 0.05). Also, there was no association between bond strength of OrthoMTA with or without intracanal medicament (p value > 0.05) and between failure mode and root filling materials (p value > 0.05). The prominent failure mode for all groups was cohesive.
CONCLUSION: Prior application of Diapex has no effect on the bond strength of iRoot SP and OrthoMTA. However, Odontopaste improved the bond strength of iRoot SP.
CLINICAL SIGNIFICANCE: Dislodgment resistance of root canal filling from root dentin could be an indicator of the durability and prognosis of endodontic treated teeth.

Matched MeSH terms: Silicates
Fulltext Fly ash-based geopolymer lightweight concrete using foaming agent

Al Bakri Abdullah MM, Hussin K, Bnhussain M, Ismail KN, Yahya Z, Razak RA

Int J Mol Sci, 2012;13(6):7186-98.
PMID: 22837687 DOI: 10.3390/ijms13067186

In this paper, we report the results of our investigation on the possibility of producing foam concrete by using a geopolymer system. Class C fly ash was mixed with an alkaline activator solution (a mixture of sodium silicate and NaOH), and foam was added to the geopolymeric mixture to produce lightweight concrete. The NaOH solution was prepared by dilute NaOH pellets with distilled water. The reactives were mixed to produce a homogeneous mixture, which was placed into a 50 mm mold and cured at two different curing temperatures (60 °C and room temperature), for 24 hours. After the curing process, the strengths of the samples were tested on days 1, 7, and 28. The water absorption, porosity, chemical composition, microstructure, XRD and FTIR analyses were studied. The results showed that the sample which was cured at 60 °C (LW2) produced the maximum compressive strength for all tests, (11.03 MPa, 17.59 MPa, and 18.19 MPa) for days 1, 7, and 28, respectively. Also, the water absorption and porosity of LW2 were reduced by 6.78% and 1.22% after 28 days, respectively. The SEM showed that the LW2 sample had a denser matrix than LW1. This was because LW2 was heat cured, which caused the geopolymerization rate to increase, producing a denser matrix. However for LW1, microcracks were present on the surface, which reduced the compressive strength and increased water absorption and porosity.

Matched MeSH terms: Silicates/chemistry*
Environmental evaluation and nano-mineralogical study of fresh and unsaturated weathered coal fly ashes

Akinyemi SA, Gitari WM, Petrik LF, Nyakuma BB, Hower JC, Ward CR, et al.

Sci Total Environ, 2019 May 01;663:177-188.
PMID: 30711584 DOI: 10.1016/j.scitotenv.2019.01.308

Coal combustion and the disposal of combustion wastes emit enormous quantities of nano-sized particles that pose significant health concerns on exposure, particularly in unindustrialized countries. Samples of fresh and weathered class F fly ash were analysed through various techniques including X-ray fluorescence (XRF), X-ray diffraction (XRD), focused ion beam scanning electron microscopy (FIB-SEM), field-emission gun scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM) coupled with energy dispersive x-ray spectroscopy (EDS), and Raman Spectroscopy. The imaging techniques showed that the fresh and weathered coal fly ash nanoparticles (CFA-NPs) are mostly spherical shaped. The crystalline phases detected were quartz, mullite, ettringite, calcite, maghemite, hematite, gypsum, magnetite, clay residues, and sulphides. The most abundant crystalline phases were quartz mixed with Al-Fe-Si-K-Ti-O-amorphous phases whereas mullite was detected in several amorphous phases of Al, Fe, Ca, Si, O, K, Mg, Mn, and P. The analyses revealed that CFA-NPs are 5-500 nm in diameter and encapsulate several potentially hazardous elements (PHEs). The carbon species were detected as 5-50 nm carbon nanoballs of graphitic layers and massive fullerenes. Lastly, the aspects of health risks related to exposure to some detected ambient nanoparticles are also discussed.

Matched MeSH terms: Aluminum Silicates
Fulltext Study on radon emanation from selected building materials in Malaysia

Ahmed, Al-Halemi, Jaafar, M.S.

Journal of Nuclear and Related Technologies, 2010;2010(1):14-20.
MyJurnal

Radon-222 emanation from selected locally produced samples of building materials, used in Malaysia were measured using the Professional Continuous Radon Monitor Model 1027, which is a patented electronic detecting-junction photodiode sensor to measure the concentration of radon gas. Each sample was placed for 72 hours inside a 3.11 x 10 -2 m 3 sealed container. It was found that the average radon concentration Bqm -3 of air for concrete bricks, concrete brick with cemented coatings, concrete brick with cemented coatings and paint samples were, 303.7 Bq/m 3, 436.6 Bqm -3, and 410.7 Bqm -3, respectively. (Bqm -3 ) for brown clay brick, brown clay brick with cemented coatings, brown clay brick with cemented coatings and paint were 166.5 Bqm -3, 166.5 Bqm -3, and 148 Bqm -3, respectively. (Bqm -3 ) for sample of compact ceramic tile was 0 Bqm -3. The findings show that concrete brick samples are important source of radon emanation, while brown clay brick have been accepted as the recommendation of the U.S. Environmental Protection Agency (EPA), and ceramic tiles had no emanation of radon gas due to their compact surface, or the glazed layer created on the tile surface during the manufacturing process, which blocks radon emanation. A positive correlation between radon emanation and radium content has been observed for both brown clay brick and concrete brick samples whereas a negative correlation for ceramic tile has been observed. Consequently from the findings, in order to reduce radon emanation and radon exposure in house dwellings and in addition to EPA recommendation of sealed cracks and established good ventilation, we recommend concrete walls to be painted and concrete floors to be paved with ceramic tiles.

Matched MeSH terms: Aluminum Silicates
Evaluation of groundwater and soil pollution in a landfill area using electrical resistivity imaging survey

Ahmed AM, Sulaiman WN

Environ Manage, 2001 Nov;28(5):655-63.
PMID: 11568845

Landfills are sources of groundwater and soil pollution due to the production of leachate and its migration through refuse. This study was conducted in order to determine the extent of groundwater and soil pollution within and around the landfill of Seri Petaling located in the State of Selangor, Malaysia. The condition of nearby surface water was also determined. An electrical resistivity imaging survey was used to investigate the leachate production within the landfill. Groundwater geochemistry was carried out and chemical analysis of water samples was conducted upstream and downstream of the landfill. Surface water was also analyzed in order to determine its quality. Soil chemical analysis was performed on soil samples taken from different locations within and around the landfill in the vadose zone (unsaturated zone) and below the water table (in the soil saturated zone). The resistivity image along line L-L1 indicated the presence of large zones of decomposed waste bodies saturated with highly conducting leachate. Analysis of trace elements indicated their presence in very low concentrations and did not reflect any sign of heavy metal pollution of ground and surface water or of soil. Major ions represented by Na, K, and Cl were found in anomalous concentrations in the groundwater of the downstream bore hole, where they are 99.1%, 99.2%, and 99.4%, respectively, higher compared to the upstream bore hole. Electrical conductivity (EC) was also found in anomalous concentration downstream. Ca and Mg ions represent the water hardness (which is comparatively high downstream). There is a general trend of pollution towards the downstream area. Sulfates (SO4) and nitrates (NO3) are found in the area in low concentrations, even below the WHO standards for drinking water, but are significantly higher in the surface water compared to the groundwater. Phosphate (PO4) and nitrite (NO2), although present in low levels, are significantly higher at the downstream. There is no significant difference in the amount of fluoride (F) in the different locations. In the soil vadose zone, heavy metals were found to be in their typical normal ranges and within the background concentrations. Soil exchangeable bases were significantly higher in the soil saturated zone compared to the vadose zone, and no significant difference was obtained in the levels of inorganic pollutants. With the exception of Cd, the concentration ranges of all trace elements (Cu, Zn, Cr, Pb, and Ni) of Seri Petaling landfill soils were below the upper limits of baseline concentrations published from different sources.

Matched MeSH terms: Aluminum Silicates/analysis

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