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New bioactive glass-ceramic: synthesis and application in PMMA bone cement composites

Abd Samad H, Jaafar M, Othman R, Kawashita M, Abdul Razak NH

Biomed Mater Eng, 2011;21(4):247-58.
PMID: 22182792 DOI: 10.3233/BME-2011-0673

In present study, a new composition of glass-ceramic was synthesized based on the Na2O-CaO-SiO2-P2O5 glass system. Heat treatment of glass powder was carried out in 2 stages: 600 °C as the nucleation temperature and different temperature on crystallization at 850, 950 and 1000 °C. The glass-ceramic heat-treated at 950 °C was selected as bioactive filler in commercial PMMA bone cement; (PALACOS® LV) due to its ability to form 2 high crystallization phases in comparison with 850 and 1000 °C. The results of this newly glass-ceramic filled PMMA bone cement at 0-16 wt% of filler loading were compared with those of hydroxyapatite (HA). The effect of different filler loading on the setting properties was evaluated. The peak temperature during the polymerization of bone cement decreased when the liquid to powder (L/P) ratio was reduced. The setting time, however, did not show any trend when filler loading was increased. In contrast, dough time was observed to decrease with increased filler loading. Apatite morphology was observed on the surface of the glass-ceramic and selected cement after bioactivity test.

Matched MeSH terms: Ceramics/chemical synthesis*; Ceramics/chemistry*
An endeavour from porous to 3D constructs bioceramics

Idris B, Rusnah M, Reusmaazran YM, Rohaida CH

Med J Malaysia, 2004 May;59 Suppl B:67-8.
PMID: 15468822
Matched MeSH terms: Ceramics/analysis; Ceramics/chemical synthesis*
Microstructure and strength of extruded porous HA ceramics

Rusnah M, Andanastuti M, Idris B

Med J Malaysia, 2004 May;59 Suppl B:83-4.
PMID: 15468830

The paper discusses the influence of sintering temperature on the microstructure and strength of hydroxyapatite ceramics prepared using the extrusion process. The average pore diameters observed were in the range of approximately 150mm to 300mm whereas the compaction strength was found to be around 120-160 MPa.

Matched MeSH terms: Ceramics/analysis*; Ceramics/chemical synthesis
Bioglass® 45S5-based composites for bone tissue engineering and functional applications

Rizwan M, Hamdi M, Basirun WJ

J Biomed Mater Res A, 2017 Nov;105(11):3197-3223.
PMID: 28686004 DOI: 10.1002/jbm.a.36156

Bioglass® 45S5 (BG) has an outstanding ability to bond with bones and soft tissues, but its application as a load-bearing scaffold material is restricted due to its inherent brittleness. BG-based composites combine the amazing biological and bioactive characteristics of BG with structural and functional features of other materials. This article reviews the composites of Bioglass® in combination with metals, ceramics and polymers for a wide range of potential applications from bone scaffolds to nerve regeneration. Bioglass® also possesses angiogenic and antibacterial properties in addition to its very high bioactivity; hence, composite materials developed for these applications are also discussed. BG-based composites with polymer matrices have been developed for a wide variety of soft tissue engineering. This review focuses on the research that suggests the suitability of BG-based composites as a scaffold material for hard and soft tissues engineering. Composite production techniques have a direct influence on the bioactivity and mechanical behavior of scaffolds. A detailed discussion of the bioactivity, in vitro and in vivo biocompatibility and biodegradation is presented as a function of materials and its processing techniques. Finally, an outlook for future research is also proposed. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3197-3223, 2017.

Matched MeSH terms: Ceramics/metabolism; Ceramics/chemistry*
Hydroxapatite and tricalcium phosphate prepared by precipitation method

Cik Rohaida CH, Idris B, Mohd Reusmaazran Y, Rusnah M, Fadzley Izwan AM

Med J Malaysia, 2004 May;59 Suppl B:156-7.
PMID: 15468865

A mixture with different compositions of HA and TCP were synthesize in this work by precipitation method using Ca(NO3)2 4H2 and (NH4)2HPO4 as the starting materials. A mixture with HA and TCP phases in different ratios were produced. The powders were sintered from 1000 degrees C to 1250 degrees C. The phase compositions of the mixtures were then studied via XRD. This work shows that the pH value determines the different phase compositions of the HA-TCP mixture. Chemical analyses were carried out by FTIR. The microstructure was observed under SEM.

Matched MeSH terms: Ceramics/analysis; Ceramics/chemical synthesis*
Mechanical and cytotoxicity properties of hybrid ceramics filled polyamide 12 filament feedstock for craniofacial bone reconstruction via fused deposition modelling

Abdullah AM, Rahim TNAT, Hamad WNFW, Mohamad D, Akil HM, Rajion ZA

Dent Mater, 2018 11;34(11):e309-e316.
PMID: 30268678 DOI: 10.1016/j.dental.2018.09.006

OBJECTIVE: To compare the mechanical and biological properties of newly developed hybrid ceramics filled and unfilled polyamide 12 (PA 12) for craniofacial reconstruction via a fused deposition modelling (FDM) framework.
METHODS: 15wt% of zirconia (ZrO2) as well as 30, 35, and 40wt% of beta-tricalcium phosphate (β-TCP) were compounded with PA 12, followed by the fabrication of filament feedstocks using a single screw extruder. The fabricated filament feedstocks were used to print the impact specimens. The melt flow rate, tensile properties of fabricated filament feedstocks, and 3D printed impact properties of the specimens were assessed using melt flow indexer, universal testing machine, and Izod pendulum tester, respectively. The microstructure of selected filament feedstocks and broken impact specimens were analysed using a field emission scanning electron microscope and universal testing machine. Human periodontal ligament fibroblast cells (HPdLF) were used to evaluate the cytotoxicity of the materials by (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromid) (MTT) assay.
RESULTS: Hybrid ceramics filled PA 12 indicated sufficient flowability for FDM 3D printing. The tensile strength of hybrid ceramics filled PA 12 filament feedstocks slightly reduced as compared to unfilled PA 12. However, the tensile modulus and impact strength of hybrid ceramics filled PA 12 increased by 8%-31% and 98%-181%, respectively. A significant increase was also detected in the cell viability of the developed composites at concentrations of 12.5, 25, 50 and 100mg/ml.
SIGNIFICANCE: The newly developed hybrid ceramics filled PA 12 filament feedstock with improved properties is suitable for an FDM-based 3D printer, which enables the creation of patient-specific craniofacial implant at a lower cost to serve low-income patients.

Matched MeSH terms: Ceramics/toxicity; Ceramics/chemistry*
Strain measurements and fracture resistance of endodontically treated premolars restored with all-ceramic restorations

Seow LL, Toh CG, Wilson NH

J Dent, 2015 Jan;43(1):126-32.
PMID: 25448436 DOI: 10.1016/j.jdent.2014.10.001

OBJECTIVES: The aim of this study was to investigate the recovery of cuspal stiffness and fracture resistance in endodontically treated maxillary premolars restored with bonded ceramic inlays and onlays of various designs.
METHODS: Seventy intact premolars were selected for this study; six cavity designs were investigated: (i) mesio-occlusal-distal (MOD) inlay (I), (ii) MOD inlay with palatal cusp coverage (IPC), (iii) MOD onlay (O), (iv) MOD inlay with pulp chamber extension (IPE), (v) MOD inlay with palatal cusp coverage and pulp chamber extension (IPCPE), and (vi) MOD onlay with pulp chamber extension (OPE). Intact teeth acted as control. Strain gauges were attached to the buccal and palatal surfaces of the teeth to measure cuspal stiffness under static loading. All specimens were eventually subjected to compressive load to failure. Cuspal stiffness and fracture resistance data were analyzed using ANOVA and Tukey test.
RESULTS: The I and IPE restorations restored cuspal stiffness to 75% of the sound tooth value. The O and OPE restored teeth had stiffness values greater than that of a sound tooth. The I, IPC, O, IPE, IPCPE and OPE restored teeth demonstrated fracture strength values of 938N±113 N (s.d.), 1073N±176 N and 1317N±219 N, 893N±129 N, 1062N±153 N and 1347N±191 N respectively.
CONCLUSIONS: Within the limitations of this study, it was concluded that the all-ceramic onlay or inlay with palatal cusp coverage provided best biomechanical advantage in restoring an endodontically treated maxillary premolar tooth.
CLINICAL SIGNIFICANCE: The onlay approach which is more conservative compared to full coverage restoration is considered an appropriate approach to the restoration of endodontically treated maxillary premolars. The addition of a pulpal extension to the all-ceramic restorations, apart from being technically challenging, was not found to offer any biomechanical advantage to the restored teeth.
KEYWORDS: Endodontically treated teeth; Fracture strengths; Inlay; Onlay; Pulp chamber extension; Strains

Matched MeSH terms: Ceramics
Fulltext Carbon Nanotubes (CNTs)-Reinforced Magnesium-Based Matrix Composites: A Comprehensive Review

Abazari S, Shamsipur A, Bakhsheshi-Rad HR, Ismail AF, Sharif S, Razzaghi M, et al.

Materials (Basel), 2020 Oct 04;13(19).
PMID: 33020427 DOI: 10.3390/ma13194421

In recent years considerable attention has been attracted to magnesium because of its light weight, high specific strength, and ease of recycling. Because of the growing demand for lightweight materials in aerospace, medical and automotive industries, magnesium-based metal matrix nanocomposites (MMNCs) reinforced with ceramic nanometer-sized particles, graphene nanoplatelets (GNPs) or carbon nanotubes (CNTs) were developed. CNTs have excellent material characteristics like low density, high tensile strength, high ratio of surface-to-volume, and high thermal conductivity that makes them attractive to use as reinforcements to fabricate high-performance, and high-strength metal-matrix composites (MMCs). Reinforcing magnesium (Mg) using small amounts of CNTs can improve the mechanical and physical properties in the fabricated lightweight and high-performance nanocomposite. Nevertheless, the incorporation of CNTs into a Mg-based matrix faces some challenges, and a uniform distribution is dependent on the parameters of the fabricating process. The characteristics of a CNTs reinforced composite are related to the uniform distribution, weight percent, and length of the CNTs, as well as the interfacial bonding and alignment between CNTs reinforcement and the Mg-based matrix. In this review article, the recent findings in the fabricating methods, characterization of the composite's properties, and application of Mg-based composites reinforced with CNTs are studied. These include the strategies of fabricating CNT-reinforced Mg-based composites, mechanical responses, and corrosion behaviors. The present review aims to investigate and conclude the most relevant studies conducted in the field of Mg/CNTs composites. Strategies to conquer complicated challenges are suggested and potential fields of Mg/CNTs composites as upcoming structural material regarding functional requirements in aerospace, medical and automotive industries are particularly presented.

Matched MeSH terms: Ceramics
Effect of mixing process parameters and suitability of backbone polymer for aluminum powder injection molding feedstock

Abdullahi A, Choudhury I, Azuddin M, Nahar N

Sains Malaysiana, 2017;46:477-483.

A suitable and cost-effective microfabrication technique for processing aluminum micropart is required, as the choice
of aluminum microparts for aerospace, electronics and automobile components is preferred over other metals due to its
excellent properties. Meanwhile, powder injection molding (PIM) is identified as an economical manufacturing technique
for processing ceramic and micro-metal powders into microparts and or components. Therefore, this study investigates
formulation and processing of aluminum PIM feedstock using a custom-made machine. The investigation is focused on
the effect of mixing process parameters (powder loading, rotor speed and mixing temperature) and the suitability of
the backbone polymer. The formulated PIM feedstock constituents are paraffin wax (PW), stearic acid (SA), high-density
polyethylene (HDPE)/ medium-density polyethylene (MDPE) alternatively and aluminum micro-metal powder. Taguchi
method is used for the design of experiments (DOEs) and analysis. In addition, response surface methodology (RSM) is
employed to develop empirical viscosity models. The optimum powder-binder mixing ratio of 58:42 vol. % with rotor
speed of 43 rpm were determined for preparing aluminum PIM feedstock using mini-lab mixer developed. The empirical
model developed for aluminum PIM feedstock viscosity shows a good fit with R2
values of 0.84 using HDPE and 0.96 for
MDPE binder system. This investigation demonstrates preparation and suitability of aluminum PIM feedstock using waxbased
binder system.

Matched MeSH terms: Ceramics
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: Ceramics
Fulltext Self-Fluxing Mechanism in Geopolymerization for Low-Sintering Temperature of Ceramic

Jamil NH, Abdullah MMAB, Pa FC, Mohamad H, Ibrahim WMAW, Amonpattaratkit P, et al.

Materials (Basel), 2021 Mar 10;14(6).
PMID: 33801862 DOI: 10.3390/ma14061325

Kaolin, theoretically known as having low reactivity during geopolymerization, was used as a source of aluminosilicate materials in this study. Due to this concern, it is challenging to directly produce kaolin geopolymers without pre-treatment. The addition of ground granulated blast furnace slag (GGBS) accelerated the geopolymerization process. Kaolin-GGBS geopolymer ceramic was prepared at a low sintering temperature due to the reaction of the chemical composition during the initial stage of geopolymerization. The objective of this work was to study the influence of the chemical composition towards sintering temperature of sintered kaolin-GGBS geopolymer. Kaolin-GGBS geopolymer was prepared with a ratio of solid to liquid 2:1 and cured at 60 °C for 14 days. The cured geopolymer was sintered at different temperatures: 800, 900, 1000, and 1100 °C. Sintering at 900 °C resulted in the highest compressive strength due to the formation of densified microstructure, while higher sintering temperature led to the formation of interconnected pores. The difference in the X-ray absorption near edge structure (XANES) spectra was related to the phases obtained from the X-ray diffraction analysis, such as akermanite and anothite. Thermal analysis indicated the stability of sintered kaolin-GGBS geopolymer when exposed to 1100 °C, proving that kaolin can be directly used without heat treatment in geopolymers. The geopolymerization process facilitates the stability of cured samples when directly sintered, as well as plays a significant role as a self-fluxing agent to reduce the sintering temperature when producing sintered kaolin-GGBS geopolymers.

Matched MeSH terms: Ceramics
Fulltext The State of Starch/Hydroxyapatite Composite Scaffold in Bone Tissue Engineering with Consideration for Dielectric Measurement as an Alternative Characterization Technique

Mohd Roslan MR, Mohd Kamal NL, Abdul Khalid MF, Mohd Nasir NF, Cheng EM, Beh CY, et al.

Materials (Basel), 2021 Apr 14;14(8).
PMID: 33919814 DOI: 10.3390/ma14081960

Hydroxyapatite (HA) has been widely used as a scaffold in tissue engineering. HA possesses high mechanical stress and exhibits particularly excellent biocompatibility owing to its similarity to natural bone. Nonetheless, this ceramic scaffold has limited applications due to its apparent brittleness. Therefore, this had presented some difficulties when shaping implants out of HA and for sustaining a high mechanical load. Fortunately, these drawbacks can be improved by combining HA with other biomaterials. Starch was heavily considered for biomedical device applications in favor of its low cost, wide availability, and biocompatibility properties that complement HA. This review provides an insight into starch/HA composites used in the fabrication of bone tissue scaffolds and numerous factors that influence the scaffold properties. Moreover, an alternative characterization of scaffolds via dielectric and free space measurement as a potential contactless and nondestructive measurement method is also highlighted.

Matched MeSH terms: Ceramics
Electrochemical Characteristics of a Polymer/Garnet Trilayer Composite Electrolyte for Solid-State Lithium-Metal Batteries

Walle KZ, Musuvadhi Babulal L, Wu SH, Chien WC, Jose R, Lue SJ, et al.

ACS Appl Mater Interfaces, 2021 Jan 20;13(2):2507-2520.
PMID: 33406841 DOI: 10.1021/acsami.0c17422

Although solid-state Li-metal batteries (LMBs) featuring polymer-based solid electrolytes might one day replace conventional Li-ion batteries, the poor Li-ion conductivity of solid polymer electrolytes at low temperatures has hindered their practical applications. Herein, we describe the first example of using a co-precipitation method in a Taylor flow reactor to produce the metal hydroxides of both the Ga/F dual-doped Li7La3Zr2O12 (Ga/F-LLZO) ceramic electrolyte precursors and the Li2MoO4-modified Ni0.8Co0.1Mn0.1O2 (LMO@T-LNCM 811) cathode materials for LMBs. The Li/Nafion (LiNf)-coated Ga/F-LLZO (LiNf@Ga/F-LLZO) ceramic filler was finely dispersed in the poly(vinylidene fluoride)/polyacrylonitrile/lithium bis(trifluoromethanesulfonimide)/succinonitrile matrix to give a trilayer composite polymer electrolyte (denoted "Tri-CPE") through a simple solution-casting. The bulk ionic conductivity of the Tri-CPE at room temperature was approximately 4.50 × 10-4 S cm-1 and exhibited a high Li+ ion transference number (0.84). It also exhibits a broader electrochemical window of 1-5.04 V versus Li/Li+. A full cell based on a CR2032 coin cell containing the LMO@T-LNCM811-based composite cathode, when cycled under 1 C/1 C at room temperature for 300 cycles, achieved an average Columbic efficiency of 99.4% and a capacity retention of 89.8%. This novel fabrication strategy for Tri-CPE structures has potential applications in the preparation of highly safe high-voltage cathodes for solid-state LMBs.

Matched MeSH terms: Ceramics
Fulltext A Study on the Utilization of Coal Fly Ash Derived Grog in Clay Ceramics

Choo TF, Mohd Salleh MA, Kok KY, Matori KA, Abdul Rashid S

Materials (Basel), 2020 Nov 18;13(22).
PMID: 33218206 DOI: 10.3390/ma13225218

Grog is an additive material that plays important roles in ceramic making. It improves the fabrication process of green bodies as well as the physical properties of fired bodies. Few low-cost materials and wastes have found their application as grog in recent years, thus encouraging the replacement of commercial grogs with cost-saving materials. Coal fly ash, a combustion waste produced by coal-fired power plant, has the potential to be converted into grog owing to its small particle sizes and high content of silica and alumina. In this study, grog was derived from coal fly ash and mixed with kaolin clay to produce ceramics. Effects of the grog addition on the resultant ceramics were investigated. It was found that, to a certain extent, the grog addition reduced the firing shrinkage and increased the total porosity of the ceramics. The dimensional stability of the ceramics at a firing temperature of 1200 °C was also not noticeably affected by the grog. However, the grog addition in general had negative effects on the biaxial flexural strength and refractoriness of the ceramics.

Matched MeSH terms: Ceramics
Fulltext Comparison of Foam Glass-Ceramics with Different Composition Derived from Ark Clamshell (ACS) and Soda Lime Silica (SLS) Glass Bottles Sintered at Various Temperatures

Hisham NAN, Zaid MHM, Aziz SHA, Muhammad FD

Materials (Basel), 2021 Jan 26;14(3).
PMID: 33530370 DOI: 10.3390/ma14030570

Soda lime silica (SLS) waste as the source of silica (SiO2) and ark clamshell (ACS) as the foaming agent has been utilized to fabricate the low-cost and lightweight foam glass-ceramics. A series of 1 and 6 wt% foam glass-ceramics were successfully prepared by the conventional solid-state sintering method at various sintering temperatures for 60 min. The bulk density of the samples has achieved minimum density (1.014 g/cm3) with maximum expansion (62.31%) at 6 wt% of the ACS content sintered at 800 °C for 60 min. The bulk density increases while the linear shrinkage and total porosity decrease with the progression of ACS contents and sintering temperature, where the results correspond with the FESEM micrograph. The result of XRD and FTIR transmittance spectra have shown that the formation of wollastonite crystal has occurred starting at 6 wt% of the ACS content sintered at 800 °C for 30 min. The highest mechanical performance (3.90 MPa) with an average total porosity (8.04%) is observed for the sample containing 1 wt% of ACS. It can be concluded that the composition of foam glass-ceramics (1 and 6 wt%) and sintering temperatures give significant results to the structural, physical, and mechanical properties of the fabricated foam glass-ceramics.

Matched MeSH terms: Ceramics
Conservative management of extensively damaged endodontically treated tooth using computer-aided design and computer-aided manufacturing-based hybrid-ceramic endocrown: A clinical report

Ang Y, Tew IM

J Conserv Dent, 2021 02 11;23(6):644-647.
PMID: 34083924 DOI: 10.4103/JCD.JCD_533_20

Restoring extensively damaged endodontically treated posterior teeth is always a challenge in dentistry. The use of endocrowns has gained popularity in restoring severely damaged endodontically treated teeth (ETT) in recent years. In this clinical report, a structurally compromised mandibular second molar with symptomatic irreversible pulpitis and normal apical tissue was endodontically treated. Surgical crown lengthening was attempted thereafter to increase the crown height. However, marginal periodontal tissue re-growth occurred after surgical crown lengthening. The tooth was subsequently restored with endocrown which was fabricated using computer-aided design and computer-aided manufacturing-based hybrid-ceramic. In conclusion, endocrown can be a viable restorative modality for ETT with compromised clinical crown height.

Matched MeSH terms: Ceramics
Fulltext Preparation and characterization of glass-ceramic synthesized from soda lime glass and wastewater sludge

Zaidan Abdul Wahab, Syaharudin Zaibon, Khamirul Amin Matori, Norfarezah Hanim Edros, Thai, Ming Yeow, Mohd Zul Hilmi Mayzan, et al.

Pertanika Journal of Science & Technology, 2010;18(2):-.
MyJurnal

This paper reports an alternative method for making glass-ceramic from disposal waste water
sludge and soda lime silica (SLS) glass. The glass ceramic samples were prepared from a mixture
of wastewater sludge and SLS glasses, melted at 1375°C for 3 hours and quenched by pouring into
water to obtain a coarse frit. The frit glass was then crushed and sieved to 106μm before it was
pressed to a pellet. The sintering process was performed at various temperatures between 700-
1000°C for 2 hours and morphologically characterized with XRD, SEM, and EDX. Overall results
showed the crystalline phase of diopside sodian-critobalite glass-ceramic is depending on thermal
treatment process and making them attractive to industrial uses such as in construction, tiling, and
glass-ceramic applications.

Matched MeSH terms: Ceramics
Fulltext Recovery of uranium from Malaysian non-conventional sources

Meor Yusoff, M.S.

Journal of Nuclear and Related Technologies, 2010;2010(2):55-65.
MyJurnal

The recovery of uranium from non-conventional sources has its importance in the security of nuclear fuel supply as well as producing a more value-added product to the contaminated source. In this paper, uranium is recovered both by developing a hydrothermal process as well as using the removal method. Developing hydrothermal process involves using high uranium concentrated starting material such as xenotime and thorium hydroxide waste produced from the monazite cracking process. Oxalate separation enable to produce a better uranium and thorium separation from the yttrium in xenotime as compared to the hydroxide precipitation. Also, a solvent extraction stage was included to separate the uranium from the thorium in the process using thorium hydroxide waste. The removal method involves using selective leaching for minerals with lower uranium content such as zircon. A better removal for uranium and thorium in zircon is achieved when a heat treatment process was done prior to the leaching stage. White zircon mineral was produced after this treatment and its quality meets the requirement for white ceramic opacifier and glaze.

Matched MeSH terms: Ceramics
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: Ceramics
Fulltext Heat treatment effect with the electrode contact of CaCu3Ti4O12

Muhammad Azwadi Sulaiman, Hutagalung, Sabar D., Zainal A. Ahmad

Journal of Nuclear and Related Technologies, 2013;2013(2):43-52.
MyJurnal

CaCu3Ti4O12 (CCTO) has attracted a great attention for electronic devices miniaturization due to its
very high dielectric constant properties at a wide range of frequency and nearly constant over broad temperature range. The origins of the giant dielectric constant have been speculated from electrical heterogeneous of interior elements of the CCTO ceramics. Four origins were suggested contributed to the electrical heterogeneous. In this study heat treatment were done with the electrode contact in Argon gas environment and the electrical properties over very wide frequency of CCTO ceramics were investigated. Cylindrical CCTO pellets samples were prepared by solid state reaction method and single phase of XRD pattern was obtained after sintering processes. Electrical impedance responds were measured at frequency from 100 Hz to 1 GHz for the samples for untreated and heat treated at 200ºC, 250ºC, 300ºC, 350ºC and 400ºC of CCTO. Improvement to the dielectric constant can be seen for 350ºC and 400ºC samples and dielectric loss were improved for 200ºC and 300ºC samples for overall frequency. The variations were discussed based on oxygen deficiency content and resistivity of the elements inside of CCTO structure.

Matched MeSH terms: Ceramics

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