Displaying publications 1 - 20 of 310 in total

Abstract:
Sort:
  1. Uthirajoo E, Ramiah H, Kanesan J, Reza AW
    PLoS One, 2014;9(7):e101862.
    PMID: 25033049 DOI: 10.1371/journal.pone.0101862
    For the first time, a new circuit to extend the linear operation bandwidth of a LTE (Long Term Evolution) power amplifier, while delivering a high efficiency is implemented in less than 1 mm2 chip area. The 950 µm × 900 µm monolithic microwave integrated circuit (MMIC) power amplifier (PA) is fabricated in a 2 µm InGaP/GaAs process. An on-chip analog pre-distorter (APD) is designed to improve the linearity of the PA, up to 20 MHz channel bandwidth. Intended for 1.95 GHz Band 1 LTE application, the PA satisfies adjacent channel leakage ratio (ACLR) and error vector magnitude (EVM) specifications for a wide LTE channel bandwidth of 20 MHz at a linear output power of 28 dBm with corresponding power added efficiency (PAE) of 52.3%. With a respective input and output return loss of 30 dB and 14 dB, the PA's power gain is measured to be 32.5 dB while exhibiting an unconditional stability characteristic from DC up to 5 GHz. The proposed APD technique serves to be a good solution to improve linearity of a PA without sacrificing other critical performance metrics.
    Matched MeSH terms: Microwaves
  2. Soltani N, Saion E, Hussein MZ, Erfani M, Abedini A, Bahmanrokh G, et al.
    Int J Mol Sci, 2012;13(10):12242-58.
    PMID: 23202896 DOI: 10.3390/ijms131012242
    ZnS and CdS nanoparticles were prepared by a simple microwave irradiation method under mild conditions. The obtained nanoparticles were characterized by XRD, TEM and EDX. The results indicated that high purity of nanosized ZnS and CdS was successfully obtained with cubic and hexagonal crystalline structures, respectively. The band gap energies of ZnS and CdS nanoparticles were estimated using UV-visible absorption spectra to be about 4.22 and 2.64 eV, respectively. Photocatalytic degradation of methylene blue was carried out using physical mixtures of ZnS and CdS nanoparticles under a 500-W halogen lamp of visible light irradiation. The residual concentration of methylene blue solution was monitored using UV-visible absorption spectrometry. From the study of the variation in composition of ZnS:CdS, a composition of 1:4 (by weight) was found to be very efficient for degradation of methylene blue. In this case the degradation efficiency of the photocatalyst nanoparticles after 6 h irradiation time was about 73% with a reaction rate of 3.61 × 10-3 min-1. Higher degradation efficiency and reaction rate were achieved by increasing the amount of photocatalyst and initial pH of the solution.
    Matched MeSH terms: Microwaves
  3. Foo KY, Hameed BH
    Bioresour Technol, 2011 Oct;102(20):9814-7.
    PMID: 21871796 DOI: 10.1016/j.biortech.2011.07.102
    Rice husk (RH), an abundant by-product of rice milling, was used for the preparation of activated carbon (RHAC) via KOH and K(2)CO(3) chemical activation. The activation process was performed at the microwave input power of 600 W for 7 min. RHACs were characterized by low temperature nitrogen adsorption/desorption, scanning electron microscopy and Fourier transform infrared spectroscopy. The adsorption behavior was examined using methylene blue as adsorbate. The K(2)CO(3)-activated sample showed higher yield and better pore structures and adsorption capacity development than the KOH-activated sample, with a BET surface area, total pore volume and monolayer adsorption capacity of 1165 m(2)/g, 0.78 cm(3)/g and 441.52 mg/g, respectively. The results revealed the feasibility of microwave heating for preparation of high surface area activated carbons from rice husks via K(2)CO(3) activation.
    Matched MeSH terms: Microwaves*
  4. Foo KY, Hameed BH
    Bioresour Technol, 2013 Feb;130:696-702.
    PMID: 23334029 DOI: 10.1016/j.biortech.2012.11.146
    In this work, preparation of granular activated carbon from oil palm biodiesel solid residue, oil palm shell (PSAC) by microwave assisted KOH activation has been attempted. The physical and chemical properties of PSAC were characterized using scanning electron microscopy, volumetric adsorption analyzer and elemental analysis. The adsorption behavior was examined by performing batch adsorption experiments using methylene blue as dye model compound. Equilibrium data were simulated using the Langmuir, Freundlich and Temkin isotherm models. Kinetic modeling was fitted to the pseudo-first-order, pseudo-second-order and Elovich kinetic models, while the adsorption mechanism was determined using the intraparticle diffusion and Boyd equations. The result was satisfactory fitted to the Langmuir isotherm model with a monolayer adsorption capacity of 343.94mg/g at 30°C. The findings support the potential of oil palm shell for preparation of high surface area activated carbon by microwave assisted KOH activation.
    Matched MeSH terms: Microwaves
  5. Wong TW
    Curr Drug Deliv, 2008 Apr;5(2):77-84.
    PMID: 18393808
    Microwave has received a widespread application in pharmaceuticals and food processing, microbial sterilization, biomedical therapy, scientific and biomedical analysis, as well as, drug synthesis. This paper reviews the basis of application of microwave to prepare pharmaceutical dosage forms such as agglomerates, gel beads, microspheres, nanomatrix, solid dispersion, tablets and film coat. The microwave could induce drying, polymeric crosslinkages as well as drug-polymer interaction, and modify the structure of drug crystallites via its effects of heating and/or electromagnetic field on the dosage forms. The use of microwave opens a new approach to control the physicochemical properties and drug delivery profiles of pharmaceutical dosage forms without the need for excessive heat, lengthy process or toxic reactants. Alternatively, the microwave can be utilized to process excipients prior to their use in the formulation of drug delivery systems. The intended release characteristics of drugs in dosage forms can be met through modifying the physicochemical properties of excipients using the microwave.
    Matched MeSH terms: Microwaves*
  6. Nizamuddin S, Siddiqui MTH, Baloch HA, Mubarak NM, Griffin G, Madapusi S, et al.
    Environ Sci Pollut Res Int, 2018 Jun;25(18):17529-17539.
    PMID: 29663294 DOI: 10.1007/s11356-018-1876-7
    The process parameters of microwave hydrothermal carbonization (MHTC) have significant effect on yield of hydrochar. This study discusses the effect of process parameters on hydrochar yield produced from MHTC of rice husk. Results revealed that, over the ranges tested, a lower temperature, lower reaction time, lower biomass to water ratio, and higher particle size produce more hydrochar. Maximum hydrochar yield of 62.8% was obtained at 1000 W, 220 °C, and 5 min. The higher heating value (HHV) was improved significantly from 6.80 MJ/kg of rice husk to 16.10 MJ/kg of hydrochar. Elemental analysis results showed that the carbon content increased and oxygen content decreased in hydrochar from 25.9 to 47.2% and 68.5 to 47.0%, respectively, improving the energy and combustion properties. SEM analysis exhibited modification in structure of rice husk and improvement in porosity after MHTC, which was further confirmed from BET surface analysis. The BET surface area increased from 25.0656 m2/g (rice husk) to 92.6832 m2/g (hydrochar). Thermal stability of hydrochar was improved from 340 °C for rice husk to 370 °C for hydrochar.
    Matched MeSH terms: Microwaves
  7. Moses LB, Abu Bakar MF, Mamat H, Aziz ZA
    PMID: 33603822 DOI: 10.1155/2021/8811236
    The present study was conducted to determine the cytotoxicity effect of Eurycoma longifolia (Jack.) leaf extracts and also its possible anticancer mechanism of action against breast cancer cell lines: non-hormone-dependent MDA-MB-231 and hormone-dependent MCF-7. The leaves of E. longifolia were processed into unfermented and fermented batches before drying using freeze and microwave-oven drying techniques. Obtained extracts were tested for cytotoxicity effect using MTT assay and phenolic determination using HPLC-DAD technique. The most toxic sample was analyzed for its apoptotic cell quantification, cell cycle distribution, and the expression of caspases and apoptotic protein using flow cytometry technique. Fragmentation of DNA was tested using an agarose gel electrophoresis system. The results determined that the unfermented freeze-dried leaf extract was the most toxic towards MDA-MB-231 and MCF-7 cells, in a dose-dependent manner. This extract contains the highest phenolics of gallic acid, chlorogenic acid, ECG, and EGCG. The DNA fragmentation was observed in both cell lines, where cell cycle was arrested at the G2/M phase in MCF-7 cells and S phase in MDA-MB-231 cells. The number of apoptotic cells for MDA-MB-231 was increased when the treatment was prolonged from 24 h to 48 h but slightly decreased at 72 h, whereas apoptosis in MCF-7 cells occurred in a time-dependent manner. There were significant activities of cytochrome c, caspase-3, Bax, and Bcl-2 apoptotic protein in MDA-MB-231 cells, whereas MCF-7 cells showed significant activities for caspase-8, cytochrome c, Bax, p53, and Bcl-2 apoptotic protein. These results indicate the ability of unfermented freeze-dried leaf extract of E. longifolia to induce apoptosis cell death on MDA-MB-231 and MCF-7, as well as real evidence on sample preparation effect towards its cytotoxicity level.
    Matched MeSH terms: Microwaves
  8. Xu YJ, Jiang F, Song J, Yang X, Shu N, Yuan L, et al.
    J Agric Food Chem, 2020 Aug 19;68(33):8847-8854.
    PMID: 32806128 DOI: 10.1021/acs.jafc.0c03539
    The thermal pretreatment of oilseed prior to oil extraction could increase the oil yield and improve the oil quality. Phenolic compounds are important antioxidants in rapeseed oil. In this study, we investigated the impact of thermal pretreatment method on the rapeseed oil based on phenolic compound levels. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis showed that the phenolic compound contents in the microwave-pretreated oil were higher than those in the oven- and infrared-treated oils. Sinapic acid (SA) and canolol (CA), which are the top two phenolic compounds in rapeseed oil, exerted well 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity with IC50 values of 8.45 and 8.80 μmol/L. The cell experiment uncovered that SA and CA have significant biological activities related to rapeseed oil quality, including increase of antioxidant enzymes superoxide dismutase (SOD), alleviation of reactive oxygen species (ROS), and cytotoxicity of HepG2 cells after the intake of excessive oleic acid. Further investigation indicated that SA and CA reduced cell apoptosis rate through Bax-Bcl-2-caspase-3 and p53-Bax-Bcl-2-caspase-3, respectively. Taken together, our findings suggest that microwave pretreatment is the best method to improve the content of phenolic compounds in rapeseed oil compared with oven and infrared pretreatments.
    Matched MeSH terms: Microwaves
  9. Mahmud MZ, Islam MT, Misran N, Almutairi AF, Cho M
    Sensors (Basel), 2018 Sep 05;18(9).
    PMID: 30189633 DOI: 10.3390/s18092951
    Globally, breast cancer is reported as a primary cause of death in women. More than 1.8 million new breast cancer cases are diagnosed every year. Because of the current limitations on clinical imaging, researchers are motivated to investigate complementary tools and alternatives to available techniques for detecting breast cancer in earlier stages. This article presents a review of concepts and electromagnetic techniques for microwave breast imaging. More specifically, this work reviews ultra-wideband (UWB) antenna sensors and their current applications in medical imaging, leading to breast imaging. We review the use of UWB sensor based microwave energy in various imaging applications for breast tumor related diseases, tumor detection, and breast tumor detection. In microwave imaging, the back-scattered signals radiating by sensors from a human body are analyzed for changes in the electrical properties of tissues. Tumorous cells exhibit higher dielectric constants because of their high water content. The goal of this article is to provide microwave researchers with in-depth information on electromagnetic techniques for microwave imaging sensors and describe recent developments in these techniques.
    Matched MeSH terms: Microwaves
  10. Awan D, Bashir S, Khan S, Al-Bawri SS, Dalarsson M
    Sensors (Basel), 2024 Feb 18;24(4).
    PMID: 38400473 DOI: 10.3390/s24041315
    Microwave medical imaging (MMI) is experiencing a surge in research interest, with antenna performance emerging as a key area for improvement. This work addresses this need by enhancing the directivity of a compact UWB antenna using a Yagi-Uda-inspired reflector antenna. The proposed reflector-loaded antenna (RLA) exhibited significant gain and directivity improvements compared to a non-directional reference antenna. When analyzed for MMI applications, the RLA showed a maximum increase of 4 dBi in the realized gain and of 14.26 dB in the transmitted field strength within a human breast model. Moreover, it preserved the shape of time-domain input signals with a high correlation factor of 94.86%. To further validate our approach, another non-directional antenna with proven head imaging capabilities was modified with a reflector, achieving similar directivity enhancements. The combined results demonstrate the feasibility of RLAs for improved performance in MMI systems.
    Matched MeSH terms: Microwaves*
  11. Orio L, Alexandru L, Cravotto G, Mantegna S, Barge A
    Ultrason Sonochem, 2012 May;19(3):591-5.
    PMID: 22054912 DOI: 10.1016/j.ultsonch.2011.10.001
    Mitragyna speciosa, a tropical plant indigenous to Southeast Asia, is well known for its psychoactive properties. Its leaves are traditionally chewed by Thai and Malaysian farmers and manual labourers as it causes a numbing, stimulating effect. The present study aims to evaluate alkaloid yield and composition in the leaf extracts. For this purpose we have compared several non-conventional extraction techniques with classic procedures (room temperature or under heating). Dried M. speciosa leaves belonging to three batches of different origin (from Thailand, Malaysia and Indonesia) were extracted using ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE) and supercritical carbon dioxide extraction SFE-CO(2), using methanol, ethanol, water and binary mixtures. The extracts were compared using an HPLC/ESI-MS analysis of mitragynine and four other related alkaloids which were present in the alkaloid fraction. The extraction technique influences both the raw product yield and the relative alkaloid content of M. speciosa leaves. Of the several methods tested, MAE in a closed vessel at 110 °C (60 W, methanol/water 1:1) gave the highest alkaloid fraction amount, while UAE with an immersion horn at 25 °C (21.4 kHz, 50 W, methanol) showed the best yield for mitragynine. This work may prove to be a useful contribution to forensic, toxicological and pharmacognosy studies. Although the potential applications of M. speciosa alkaloids clearly need further investigation, these results may facilitate the scaling-up of their extraction.
    Matched MeSH terms: Microwaves
  12. Tamjid Farki NNANL, Abdulhameed AS, Surip SN, ALOthman ZA, Jawad AH
    Int J Phytoremediation, 2023;25(12):1567-1578.
    PMID: 36794599 DOI: 10.1080/15226514.2023.2175780
    Herein, tropical fruit biomass wastes including durian seeds (DS) and rambutan peels (RP) were used as sustainable precursors for preparing activated carbon (DSRPAC) using microwave-induced H3PO4 activation. The textural and physicochemical characteristics of DSRPAC were investigated by N2 adsorption-desorption isotherms, X-ray diffraction, Fourier transform infrared, point of zero charge, and scanning electron microscope analyses. These findings reveal that the DSRPAC has a mean pore diameter of 3.79 nm and a specific surface area of 104.2 m2/g. DSRPAC was applied as a green adsorbent to extensively investigate the removal of an organic dye (methylene blue, MB) from aqueous solutions. The response surface methodology Box-Behnken design (RSM-BBD) was used to evaluate the vital adsorption characteristics, which included (A) DSRPAC dosage (0.02-0.12 g/L), (B) pH (4-10), and (C) time (10-70 min). The BBD model specified that the DSRPAC dosage (0.12 g/L), pH (10), and time (40 min) parameters caused the largest removal of MB (82.1%). The adsorption isotherm findings reveal that MB adsorption pursues the Freundlich model, whereas the kinetic data can be well described by the pseudo-first-order and pseudo-second-order models. DSRPAC exhibited good MB adsorption capability (118.5 mg/g). Several mechanisms control MB adsorption by the DSRPAC, including electrostatic forces, π-π stacking, and H-bonding. This work shows that DSRPAC derived from DS and RP could serve as a viable adsorbent for the treatment of industrial effluents containing organic dye.
    Matched MeSH terms: Microwaves
  13. Harjoh N, Wong TW, Caramella C
    Int J Pharm, 2020 Jun 30;584:119416.
    PMID: 32423875 DOI: 10.1016/j.ijpharm.2020.119416
    Inhaled/oral insulin have been investigated as an alternative to injectable insulin, but are met with unsatisfactory outcomes. Transdermal administration bears several advantages unmet by inhalation/oral delivery, but macromolecular drugs permeation is poor. This study explored microwave to elicit transdermal insulin permeation, and compared against conventional permeation enhancers (fatty acids) in vitro/in vivo. The transdermal insulin permeation was promoted by microwave (2450 MHz/1 mW) > oleic acid (monounsaturated) ~ linoleic acid (double unsaturated bonds). The linolenic acid (triple unsaturated bonds) or combination of microwave/fatty acid reduced skin insulin permeation. Transdermal insulin permeation enhancement was attributed to epidermal lipid bilayer fluidization (CH) and corneocyte shrinkage due to keratin condensation (OH/NH, CO), which had aqueous pore enlarged to facilitate insulin transport. Its reduction by linolenic acid, a molecularly larger and rigid fatty acid with higher surface tension, was due to reduced fatty acid permeation into epidermis and minimal skin microstructural changes. The oleic acid, despite favoured skin microstructural changes, did not provide a remarkably high insulin permeation due to it embedded in skin as hydrophobic shield to insulin transport. Microwave penetrates skin volumetrically with no chemical residue retention. It alone promoted insulin absorption and sustained blood glucose level reduction in vivo.
    Matched MeSH terms: Microwaves*
  14. Ahmad AF, Abbas Z, Obaiys SJ, Ibrahim N, Hashim M, Khaleel H
    PLoS One, 2015;10(10):e0140505.
    PMID: 26474301 DOI: 10.1371/journal.pone.0140505
    Bio-composites of oil palm empty fruit bunch (OPEFB) fibres and polycaprolactones (PCL) with a thickness of 1 mm were prepared and characterized. The composites produced from these materials are low in density, inexpensive, environmentally friendly, and possess good dielectric characteristics. The magnitudes of the reflection and transmission coefficients of OPEFB fibre-reinforced PCL composites with different percentages of filler were measured using a rectangular waveguide in conjunction with a microwave vector network analyzer (VNA) in the X-band frequency range. In contrast to the effective medium theory, which states that polymer-based composites with a high dielectric constant can be obtained by doping a filler with a high dielectric constant into a host material with a low dielectric constant, this paper demonstrates that the use of a low filler percentage (12.2%OPEFB) and a high matrix percentage (87.8%PCL) provides excellent results for the dielectric constant and loss factor, whereas 63.8% filler material with 36.2% host material results in lower values for both the dielectric constant and loss factor. The open-ended probe technique (OEC), connected with the Agilent vector network analyzer (VNA), is used to determine the dielectric properties of the materials under investigation. The comparative approach indicates that the mean relative error of FEM is smaller than that of NRW in terms of the corresponding S21 magnitude. The present calculation of the matrix/filler percentages endorses the exact amounts of substrate utilized in various physics applications.
    Matched MeSH terms: Microwaves*
  15. Mohd Nawi N, Muhamad II, Mohd Marsin A
    Food Sci Nutr, 2015 Mar;3(2):91-9.
    PMID: 25838887 DOI: 10.1002/fsn3.132
    This study focuses on the impact of different wall materials on the physicochemical properties of microwave-assisted encapsulated anthocyanins from Ipomoea batatas. Using the powder characterization technique, purple sweet potato anthocyanin (PSPAs) powders were analysed for moisture content, water activity, dissolution time, hygroscopicity, color and morphology. PSPAs were produced using different wall materials: maltodextrin (MD), gum arabic (GA) and a combination of gum arabic and maltodextrin (GA + MD) at a 1:1 ratio. Each of the wall materials was homogenized to the core material at a core/wall material ratio of 5 and were microencapsulated by microwave-assisted drying at 1100 W. Results indicated that encapsulated powder with the GA and MD combination presented better quality of powder with the lowest value of moisture content and water activity. With respect to morphology, the microcapsule encapsulated with GA + MD showed several dents in coating surrounding its core material, whereas other encapsulated powders showed small or slight dents entrapped onto the bioactive compound. Colorimetric analysis showed changes in values of L, a*, b*, hue and chroma in the reconstituted powder compared to the initial powder.
    Matched MeSH terms: Microwaves
  16. Li KS, Ali A, Muhammad II
    Acta Sci Pol Technol Aliment, 2017 Jul-Sep;16(3):283-292.
    PMID: 29055976 DOI: 10.17306/J.AFS.0497
    BACKGROUND: Perah seed is one of the most underutilized oilseeds, containing high nutritional values and high percentage of α-linoleneic acid, which may have a high potential in food and pharmaceutical applica- tions. The main objective of this study was to evaluate the influence of microwave (MW) cooking on the proximate composition and antioxidant activity of perah seeds.

    METHODS: In this study, the proximate composition and amygdalin concentration of MW ir- radiated perah seeds were determined. The total phenolic content (TPC), Maillard reaction products (MRPs) and antioxidant activity of methanol (PME), 70% methanol in water (PMW), ethanol (PEE), 70% ethanol  in water (PEW) extracts and methanol extract of oil (PMO) were evaluated during MW cooking. The anti- oxidant activity was evaluated using multiple assays, namely DPPH radical scavenging activity, β-Carotene bleaching assay, and reducing power.

    RESULTS: Microwave cooking did not significantly increase crude lipid and carbohydrate content, and the amounts of other nutrients such as ash, crude protein and fibre remained almost unchanged. As evaluated  by HPLC, the amygdalin concentration in the seeds was reduced by MW cooking. The TPC, MRP and anti- oxidant activity of the solvent extracts of perah seeds increased significantly with increasing roasting time. Of all the extracts, PMW at all MW cooking times displayed the highest antioxidant effectiveness. However, thermal treatment significantly reduced the antioxidant properties of PMO. The values for TPC, MRP and antioxidant effectiveness of the samples were ranked in the following order: PMW > PEW > PME > PEE > PMO, in both control and microwaved samples.

    CONCLUSIONS: In determining the overall quality of the products, MW cooking time was found to be a critical factor. Solubilization of phenolic compounds and formation of MRPs during MW cooking could have caused the increase in antioxidant activity of the perah seeds.
    Matched MeSH terms: Microwaves*
  17. Pham TV, Nguyen TT, Nguyen DT, Thuan TV, Bui PQT, Viet VND, et al.
    J Nanosci Nanotechnol, 2019 02 01;19(2):1122-1125.
    PMID: 30360214 DOI: 10.1166/jnn.2019.15926
    Recently, the graphite based materials have gained interest as excellent platforms to remove aqueous pollutants via adsorption routes. This is given that such materials possess large specific surface area and low density. In the present work, a comparative study of two facile and effective approaches is conventional thermal heating and microwave irradiation methods to fabricate expanded graphite from available flake graphite sources of Vietnam for oil-contaminated water purification. The as-prepared expanded graphite was characterized by using FT-IR, SEM, XRD and BET analysis. The results exhibited that expanded graphite has multilevel pore structures and the surface area of expanded graphite obtained from microwave irradiation and conventional heating was 147.5 (m²/g) and 100.97 (m²/g) under optimal processing conditions. The as-synthesized expanded graphite from the microwave irradiation method was found to have higher adsorption capacities for diesel oil, crude oil, and fuel oil compared to conventional heating method.
    Matched MeSH terms: Microwaves
  18. Abdulsalam M, Che Man H, Isma Idris A, Zainal Abidin Z, Faezah Yunos K
    PMID: 30304814 DOI: 10.3390/ijerph15102200
    Palm oil mill effluent contains carcinogenic coloured compounds that are difficult to separate due to their aromatic structure. Though colour treatment using adsorption processes at lower pH (<4) have been reported effectual, due to its acidity the remediated effluent poses an environmental hazard as a result. Thus, the current study focused on achieving decolourization at neutral pH by enhancing the morphology of the coconut shell activated carbon (CSAC) using N₂ as activating-agent with microwave irradiation heating. The microwave pretreated and non-pretreated CSAC were characterized using scanned electron microscopy (SEM), energy dispersive X-ray (EDX) and Brunauer-Emmett-Teller (BET) analysis. A significant modification in the porous structure with a 66.62% increase in the specific surface area was achieved after the pretreatment. The adsorption experimental matrix was developed using the central composite design to investigate the colour adsorption performance under varied pH (6⁻7), dosage (2⁻6 g) and contact time (10⁻100 min). At optimum conditions of neutral pH (7), 3.208 g dosage and contact time of 35 min, the percentage of colour removal was 96.29% with negligible differences compared with the predicted value, 95.855%. The adsorption equilibrium capacity of 1430.1 ADMI × mL/g was attained at the initial colour concentration of 2025 ADMI at 27 °C. The experimental data fitted better with the Freundlich isotherm model with R² 0.9851.
    Matched MeSH terms: Microwaves*
  19. Li KS, Ali MA, Muhammad II, Othman NH, Noor AM
    J Oleo Sci, 2018 May 01;67(5):497-505.
    PMID: 29628486 DOI: 10.5650/jos.ess17203
    The impact of microwave roasting on the thermooxidative degradation of perah seed oil (PSO) was evaluated during heating at a frying temperature (170°C). The roasting resulted significantly lower increment of the values of oxidative indices such as free acidity, peroxide value, p-anisidine, total oxidation (TOTOX), specific extinctions and thiobarbituric acid in oils during heating. The colour L* (lightness) value dropped gradually as the heating time increased up to 12 h, whereas a*(redness) and b* (yellowness) tended to increase. The viscosity and total polar compound in roasted PSO was lower as compared to that in unroasted one at each heating times. The tocol retention was also high in roasted samples throughout the heating period. The relative contents of polyunsaturated fatty acids (PUFAs) were decreased to 94.42% and saturated fatty acids (SFAs) were increased to 110.20% in unroasted sample, after 12 h of heating. On the other hand, in 3 min roasted samples, the relative contents of PUFAs were decreased to 98.08% and of SFAs were increased to 103.41% after 12 h of heating. Outcome from analyses showed that microwave roasting reduced the oxidative deteriorations of PSO during heating.
    Matched MeSH terms: Microwaves*
  20. Ibrahim Lakin I, Abbas Z, Azis RS, Ibrahim NA, Abd Rahman MA
    Materials (Basel), 2020 Oct 14;13(20).
    PMID: 33066690 DOI: 10.3390/ma13204581
    Oil palm empty fruit bunch (OPEFB) fiber/polylactic acid (PLA)-based composites filled with 6-22 wt.% multi-walled carbon nanotubes (MWCNTs) were prepared using a melt blend method. The composites were analyzed using X-ray diffraction (XRD), Fourier transforms infrared (FTIR), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) of the MWCNTs. The composites were characterized for complex permittivity using the coaxial probe at 8-12 GHz range and the transmission/reflection coefficients were measured through micro strip line. The dielectric permittivity measurements carried out at X-band frequency revealed that 22 wt.% MWCNTs nanocomposite display higher dielectric constant (ε') and dielectric loss (ε″) values of 4.23 and 0.65, respectively. A maximum absorption loss of 15.2 dB was obtained for the 22 wt.% nanocomposites at 11.75 GHz. This result suggests that PLA/OPEFB/MWCNTs composites are a promising cheap and lightweight material for the effective microwave absorption in the X-band frequency range.
    Matched MeSH terms: Microwaves
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links