Displaying publications 1 - 20 of 172 in total

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  1. Fulltext Selective leaching of fe from radioactive malaysian zircon mineral
    Meor Yusoff, M.S., Latifah Amin
    Journal of Nuclear and Related Technologies, 2009;2009(2):70-77.
    MyJurnal
    XRF analysis was done on a local zircon samples and the result shows it has a high Fe, Th and U content. The high Fe content in Malaysian zircon had made the mineral to be classified as of a low-grade zircon. Presence of Fe in this mineral may be resulted from clay mineral coating found on the zircon surface. Chemical leaching technique was used for the removal of this Fe and the study also shows that a 600 o C heat pretreatment stage is important for the effectiveness of this process. Other parameters studied are the HCl concentration, leaching temperature and time. By using the optimum leaching parameters, the Fe content had been reduced to 0.049% and thus qualified it to be categorised as a premium grade zircon.
    Matched MeSH terms: Aluminum Silicates; Silicates
  2. 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
  3. Fulltext Preliminary survey on potential slope instability and soil physico-chemical characteristic in Cameron Highlands, Pahang. (Tinjauan awal potensi ketidakstabilan cerun dan cirian fiziko-kimia tanah di Cameron Highlands, Pahang)
    Zulfahmi Ali Rahman, Sahibin Abd. Rahim, Wan Muhd Razi Idris, Jasni Yaakob
    Sains Malaysiana, 2007;36(2):105-116.
    Secara geologi, kawasan Cameron Highland terdiri daripada batuan granit batolit yang merejah ke dalam batuan sedimen yang lebih tua. Rejahan jasad igneus asidik ini menyebabkan pembentukan batuan meta-sedimen dan batuan metamorfik lain sebagai sisa bumbung. Sekis sering ditemui telah mengalami luluhawa tinggi hingga sepenuhnya, berwarna kelabu cerah hingga gelap dengan butiran halus hingga sederhana dan struktur foliasi yang ketara. Manakala batuan granit mengandungi mineral kuarza, felspar dan butiran biotit dan/atau turmalin. Kebanyakan cerun potongan jalan raya yang dibina merentasi jasad batuan ini dan survei ketidakstabilan cerun dilakukan berdasarkan jenis, geometri dan cirian fiziko-kimia tanah cerun. Hasil cerapan lapangan menunjukkan bahawa jenis cerun yang gagal adalah jenis cerun tanah yang terdiri daripada jenis gelinciran cetek dan dalam. Antara faktor yang menyumbang kepada ketidakstabilan cerun adalah geometri cerun seperti cerun yang tinggi dan sudut muka cerun yang curam, sifat keperoian tanah pada cerun dan kekurangan litupan vegetasi permukaan. Ini menyebabkan permukaan cerun terdedah kepada hentaman terus hujan. Kesan daripada air larian permukaan juga menyebabkan pembentukan alur-alur hakisan pada muka cerun tanah. Sifat fiziko-kimia bahan cerun (tanah) seperti taburan saiz partikel, pH, kandungan ferum oksida, bahan organik, kandungan air, ketumpatan pukal dan sebenar serta keporosan juga didapati memainkan peranan sebagai faktor yang dalaman dalam mempengaruhi kestabilan cerun tertentu yang dikaji. Julat pH tanah yang rendah (sifat asidik) pada semua cerun mengurangkan kandungan ferum oksida dalam tanah yang bertindak sebagai bahan penyimen tanah. Ini menyebabkan agregatan tanah menjadi lemah dan mudah terhakis.
    Matched MeSH terms: Aluminum Silicates
  4. 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
  5. 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*
  6. Kaolin pneumoconiosis
    CUMMINS GE, AUN YS, DAVIES TA
    Med J Malaya, 1958 Jun;12(4):613-7.
    PMID: 13577154
    Matched MeSH terms: Aluminum Silicates*
  7. Phase transformation and mechanical properties of new bioactive glass-ceramics derived from CaO-P2O5-Na2O-B2O3-SiO2 glass system
    Loh ZW, Mohd Zaid MH, Matori KA, Kechik MMA, Fen YW, Mayzan MZH, et al.
    J Mech Behav Biomed Mater, 2023 Jul;143:105889.
    PMID: 37150138 DOI: 10.1016/j.jmbbm.2023.105889
    This work investigates the role of sintering temperature on bioactive glass-ceramics derived from the new composition CaO-P2O5-Na2O-B2O3-SiO2 glass system. The sintering behaviour of the samples' physical, structural, and mechanical properties is highlighted in this study. The experimental results indicated that the sintering process improved the crystallization and hardness of the final product. Results from XRD and FTIR showed the existence of carbonate apatite, pseudo-wollastonite, and wollastonite phases. From the results, the bioglass-ceramics sintered at 700 °C obtained the highest densification and optimum mechanical results. It had the value of 5.34 ± 0.21 GPa regarding microhardness and 2.99 ± 0.24 MPa m1/2 concerning fracture toughness, which falls in the range of the human enamel. Also, the sintered samples maintained their bioactivity and biodegradability after being tested in the PBS medium. The bioactivity does not affect but slows down the apatite formation rate. Overall results promoted the novel bioglass-ceramics as a candidate material for dental application.
    Matched MeSH terms: Silicates*
  8. Fulltext Critical state of sand matrix soils
    Marto A, Tan CS, Makhtar AM, Kung Leong T
    ScientificWorldJournal, 2014;2014:290207.
    PMID: 24757417 DOI: 10.1155/2014/290207
    The Critical State Soil Mechanic (CSSM) is a globally recognised framework while the critical states for sand and clay are both well established. Nevertheless, the development of the critical state of sand matrix soils is lacking. This paper discusses the development of critical state lines and corresponding critical state parameters for the investigated material, sand matrix soils using sand-kaolin mixtures. The output of this paper can be used as an interpretation framework for the research on liquefaction susceptibility of sand matrix soils in the future. The strain controlled triaxial test apparatus was used to provide the monotonic loading onto the reconstituted soil specimens. All tested soils were subjected to isotropic consolidation and sheared under undrained condition until critical state was ascertain. Based on the results of 32 test specimens, the critical state lines for eight different sand matrix soils were developed together with the corresponding values of critical state parameters, M, λ, and Γ. The range of the value of M, λ, and Γ is 0.803-0.998, 0.144-0.248, and 1.727-2.279, respectively. These values are comparable to the critical state parameters of river sand and kaolin clay. However, the relationship between fines percentages and these critical state parameters is too scattered to be correlated.
    Matched MeSH terms: Aluminum Silicates/standards; Aluminum Silicates/chemistry
  9. Designing Calcium Silicate Cements with On-Demand Properties for Precision Endodontics
    Cahyanto A, Rath P, Teo TX, Tong SS, Malhotra R, Cavalcanti BN, et al.
    J Dent Res, 2023 Dec;102(13):1425-1433.
    PMID: 37861249 DOI: 10.1177/00220345231198185
    Calcium silicate (C3S) cements are available in kits that do not account for patients' specific needs or clinicians' preferences regarding setting time, radiopacity, mechanical, and handling properties. Moreover, slight variations in powder components and liquid content affect cement's properties and bioactivity. Unfortunately, it is virtually impossible to optimize several cement properties simultaneously via the traditional "one variable at a time" strategy, as inputs often induce trade-offs in properties (e.g., a higher water-to-powder ratio [W/P] increases flowability but decreases mechanical properties). Herein, we used Taguchi's methods and genetic algorithms (GAs) to simultaneously analyze the effect of multiple inputs (e.g., powder composition, radiopacifier concentration, and W/P) on setting time, pH, flowability, diametral tensile strength, and radiopacity, as well as prescribe recipes to produce cements with predicted properties. The properties of cements designed with GAs were experimentally tested, and the results matched the predictions. Finally, we show that the cements increased the genetic expression of odonto/osteogenic genes, alkaline phosphatase activity, and mineralization potential of dental pulp stem cells. Hence, GAs can produce cements with tailor-made properties and differentiation potential for personalized endodontic treatment.
    Matched MeSH terms: Silicates/pharmacology; Silicates/chemistry
  10. 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*
  11. Carbon dioxide sequestration of iron ore mining waste under low-reaction condition of a direct mineral carbonation process
    Kusin FM, Hasan SNMS, Molahid VLM, Yusuff FM, Jusop S
    Environ Sci Pollut Res Int, 2023 Feb;30(9):22188-22210.
    PMID: 36282383 DOI: 10.1007/s11356-022-23677-3
    Mining waste that is rich in iron-, calcium- and magnesium-bearing minerals can be a potential feedstock for sequestering CO2 by mineral carbonation. This study highlights the utilization of iron ore mining waste in sequestering CO2 under low-reaction condition of a mineral carbonation process. Alkaline iron mining waste was used as feedstock for aqueous mineral carbonation and was subjected to mineralogical, chemical, and thermal analyses. A carbonation experiment was performed at ambient CO2 pressure, temperature of 80 °C at 1-h exposure time under the influence of pH (8-12) and particle size (
    Matched MeSH terms: Silicates/chemistry
  12. Fulltext Features of DNA-Montmorillonite Binding Visualized by Atomic Force Microscopy
    Kraevsky SV, Barinov NA, Morozova OV, Palyulin VV, Kremleva AV, Klinov DV
    Int J Mol Sci, 2023 Jun 06;24(12).
    PMID: 37372975 DOI: 10.3390/ijms24129827
    In the present work, complexes of DNA with nano-clay montmorillonite (Mt) were investigated by means of atomic force microscopy (AFM) under various conditions. In contrast to the integral methods of analysis of the sorption of DNA on clay, AFM allowed us to study this process at the molecular level in detail. DNA molecules in the deionized water were shown to form a 2D fiber network weakly bound to both Mt and mica. The binding sites are mostly along Mt edges. The addition of Mg2+ cations led to the separation of DNA fibers into separate molecules, which bound mainly to the edge joints of the Mt particles according to our reactivity estimations. After the incubation of DNA with Mg2+, the DNA fibers were capable of wrapping around the Mt particles and were weakly bound to the Mt edge surfaces. The reversible sorption of nucleic acids onto the Mt surface allows it to be used for both RNA and DNA isolation for further reverse transcription and polymerase chain reaction (PCR). Our results show that the strongest binding sites for DNA are the edge joints of Mt particles.
    Matched MeSH terms: Aluminum Silicates/chemistry
  13. Mobility Studies of (14)C-Chlorpyrifos in Malaysian Oil Palm Soils
    Halimah M, Ismail BS, Nashriyah M, Maznah Z
    Bull Environ Contam Toxicol, 2016 Jan;96(1):120-4.
    PMID: 26546229 DOI: 10.1007/s00128-015-1685-3
    The mobility of (14)C-chlorpyrifos using soil TLC was investigated in this study. It was found that chlorpyrifos was not mobile in clay, clay loam and peat soil. The mobility of (14)C-chlorpyrifos and non-labelled chlorpyrifos was also tested with silica gel TLC using three types of developing solvent hexane (100%), hexane:ethyl acetate (95:5, v/v); and hexane:ethyl acetate (98:2, v/v). The study showed that both the (14)C-labelled and non-labelled chlorpyrifos have the same Retardation Factor (Rf) for different developing solvent systems. From the soil column study on mobility of chlorpyrifos, it was observed that no chlorpyrifos residue was found below 5 cm depth in three types of soil at simulation rainfall of 20, 50 and 100 mm. Therefore, the soil column and TLC studies have shown similar findings in the mobility of chlorpyrifos.
    Matched MeSH terms: Aluminum Silicates
  14. 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
  15. Fulltext Influence of Metakaolin as partially cement replacement minerals on the properties of cement and concrete
    Muhd Norhasri Mohd Sidek, Mohd Fadzil Arshad, Megat Azmi Megat Johari, Zaid Mohd Yazid, Amir Khomeiny, R.
    Scientific Research Journal, 2012;9(2):0-0.
    MyJurnal
    Metakaolin is a manufactured pozzolan produced by thermal processing of purified kaolinitic clay using electrical furnace. This study has examined the effect of Metakaolin on the properties of cement and concrete at a replacement level of 0%, 5%, 10% and 15%. The parameters studied were divided into two groups which are chemical compositions, water requirement, setting time and soundness test were carried out for cementitous properties. Workability, compressive strength and bending strength were test for concrete properties. Hardened concrete was cured under different type of curing conditions and tested.. The result showed that the inclusions of Metakaolin as cement replacement minerals have change some of the cementitous and concrete properties. This research reveals, the optimum effect for cementitous and concrete properties for metakaolin was 10%.
    Matched MeSH terms: Aluminum Silicates
  16. Fulltext Assessment of metals pollution in sediment cores from the Sabah-Sarawak coastal waters
    Zal U’yun Wan Mahmood, Zaharudin Ahmad, Che Abd Rahim Mohamed, Abdul Kadir Ishak, Norfaizal Mohammed
    Jurnal Sains Nuklear Malaysia, 2011;23(2):81-94.
    MyJurnal
    The distribution, enrichment and pollution status of metals in sediment cores from the Sabah-Sarawak coastal waters were studied. Seven sediment cores were taken in July 2004 using a gravity box corer. The metals of Cu, Zn and Pb were analyzed by ICP-MS to assess the pollution status of the sediments. The sediment fine fraction and organic carbon content was also analyzed. Enrichment Factor (EF), Geoaccumulation Index (Igeo) and Pollution Load Index (PLI) was calculated as criteria of possible contamination. The results showed that collected sediments were composed with clay, silt and sand as 12 – 74%, 27 – 72% and 0 – 20%, respectively. Meanwhile, organic carbon contents were relatively low and constant over time, based on sediment depth profiles, and it did not exceed 5% at any sampling station. The average metal concentrations in sediment cores at all sampling station were distributed in the ranges of 1.66 ± 1.36 – 6.61 ± 0.12 μgg-1 for Cu, 26.55 ± 1.04 – 57.94 ± 1.58 μgg-1 for Zn and 3.99 ± 0.10 – 14.48 ± 0.32μgg-1 for Pb. According to calculations of EF, Igeo and PLI, it can be concluded that concentrations of Cu, Zn and Pb were not significantly affected by pollution from anthropogenic sources at the seven sampling locations. Thus, the metal content of Cu, Zn and Pb in sediment should not cause pollution problem to the marine environment of Sabah-Sarawak coastal waters and further response measures are not needed.
    Matched MeSH terms: Aluminum Silicates
  17. Fulltext Soil plant transfer coefficient of 14C-carbofuran in Brassica sp. vegetable agroecosystem
    Nashriyah Mat, Mazleha Maskin, Kubiak, Roland
    Journal of Nuclear and Related Technologies, 2006;2006(1):41-50.
    MyJurnal
    The soil plant transfer coefficient or f factor of 14 C-carbofuran pesticide was studied in outdoor lysimeter experiment consisting of Brassica sp. vegetable crop, riverine alluvial clayey soil and Bungor series sandy loam soil. Soil transfer coefficients at 0-10 cm soil depth were 4.38 + 0.30, 5.76 + 1.04, 0.99 + 0.25 and 2.66 + 0.71; from 1X recommended application rate in alluvial soil, 2X recommended application rate in alluvial soil, 1X recommended application rate in Bungor soil and 2X recommended application rate in Bungor soil, respectively. At 0-25 cm soil depth, soil plant transfer coefficients were 8.96 + 0.91, 10.40 + 2.63, 2.34 + 0.68 and 6.19 + 1.40; from 1X recommended application rate in alluvial soil, 2X recommended application rate in alluvial soil, 1X recommended application rate in Bungor soil and 2X recommended application rate in Bungor soil, respectively. At 77 days after treatment (DAT), the soil plant transfer coefficient was significantly higher in riverine alluvial soil than Bungor soil whereas shoot and root growth was significantly higher in Bungor soil than in riverine alluvial soil. At both 0-10 cm Brassica sp. rooting depth and 0-25 cm soil depth, the soil plant transfer coefficient was significantly higher in 2X recommended application rate of 14 C-carbofuran as compared to 1X recommended application rate, in both Bungor and riverine alluvial soils.
    Matched MeSH terms: Aluminum Silicates
  18. 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
  19. Effect of Morphology and Size of Halloysite Nanotubes on Functional Pectin Bionanocomposites for Food Packaging Applications
    Makaremi M, Pasbakhsh P, Cavallaro G, Lazzara G, Aw YK, Lee SM, et al.
    ACS Appl Mater Interfaces, 2017 May 24;9(20):17476-17488.
    PMID: 28481104 DOI: 10.1021/acsami.7b04297
    Pectin bionanocomposite films filled with various concentrations of two different types of halloysite nanotubes were prepared and characterized in this study as potential films for food packaging applications. The two types of halloysite nanotubes were long and thin (patch) (200-30 000 nm length) and short and stubby (Matauri Bay) (50-3000 nm length) with different morphological, physical, and dispersibility properties. Both matrix (pectin) and reinforcer (halloysite nanotubes) used in this study are considered as biocompatible, natural, and low-cost materials. Various characterization tests including Fourier transform infrared spectroscopy, field emission scanning electron microscopy, release kinetics, contact angle, and dynamic mechanical analysis were performed to evaluate the performance of the pectin films. Exceptional thermal, tensile, and contact angle properties have been achieved for films reinforced by patch halloysite nanotubes due to the patchy and lengthy nature of these tubes, which form a bird nest structure in the pectin matrix. Matauri Bay halloysite nanotubes were dispersed uniformly and individually in the matrix in low and even high halloysite nanotube concentrations. Furthermore, salicylic acid as a biocidal agent was encapsulated in the halloysite nanotubes lumen to control its release kinetics. On this basis, halloysite nanotubes/salicylic acid hybrids were dispersed into the pectin matrix to develop functional biofilms with antimicrobial properties that can be extended over time. Results revealed that shorter nanotubes (Matauri Bay) had better ability for the encapsulation of salicylic acid into their lumen, while patchy structure and longer tubes of patch halloysite nanotubes made the encapsulation process more difficult, as they might need more time and energy to be fully loaded by salicylic acid. Moreover, antimicrobial activity of the films against four different strains of Gram-positive and Gram-negative bacteria indicated the effective antimicrobial properties of pectin/halloysite functionalized films and their potential to be used for food packaging applications.
    Matched MeSH terms: Aluminum Silicates
  20. Beberapa Hasil Penyiasatan Geofizik di Kawasan Bachok, Kelantan (Results on Geophysical Survey of Areas in Bachok, Kelantan)
    Abd. Rahim Samsudin, Umar Hamzah, Abd. Ghani Rafek, Haryono
    Sains Malaysiana, 1996;25.
    The whole Bachok area is covered by alluvial deposit. The alluvium has three aquifers at depth of 0 - 5, 15 - 30 and 40 - 60 meters below surface. Preliminary geophysical surveys including seismic refraction, reflection and resistivity techniques have been carried out to investigate thickness and depth of the aquifers, depth of bedrock and the salinity of the underground water. Results show that the position of first aquifer has been well determined by seismic refraction technique. Whereas the details of deeper aquifers and the bedrock have been determined by seismic reflection techniques. Geoelectrical resistivity low obtained for the first aquifer suggest that it could be due to either salt water intrusion or the presence of marine clay.
    Keseluruhan kawasan Bachok merupakan endapan aluvium. Endapan ini mempunyai tiga akuifer pada kedalaman 0 - 5 meter, 15 - 30 meter dan 40 - 60 meter. Kajian geofizik pada tahap awal yang merangkumi aspek seismos biasan, seismos pantulan dan kerintangan geoelektrik telah dilakukan untuk menyiasat ketebalan dan kedalaman akuifer, kedalaman batu dasar dan kemasinan air tanah. Hasil kajian menunjukkan bahawa teknik seismos biasan telah dapat menghasilkan maklumat mengenai kedudukan akuifer pertama. manakala teknik seismos pantulan menghasilkan maklumat terperinci mengenai akuifer kedua dan ketiga serta batu dasar. Nilai kerintangan geoelektrik rendah bagi akuifer pertama menunjukkan sama ada disebabkan oleh intrusi air masin atau kehadiran lempung samudera.
    Matched MeSH terms: Aluminum Silicates
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