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  1. Ng Kh, Wong J
    Biomed Imaging Interv J, 2008 Apr;4(2):e21.
    PMID: 21614324 DOI: 10.2349/biij.4.2.21
    Informal discussion started in 1996 and the South East Asian Federation of Organizations for Medical Physics (SEAFOMP) was officially accepted as a regional chapter of the IOMP at the Chicago World Congress in 2000 with five member countries, namely Indonesia, Malaysia, Philippines, Singapore and Thailand. Professor Kwan-Hoong Ng served as the founding president until 2006. Brunei (2002) and Vietnam (2005) joined subsequently. We are very grateful to the founding members of SEAFOMP: Anchali Krisanachinda, Kwan-Hoong Ng, Agnette Peralta, Ratana Pirabul, Djarwani S Soejoko and Toh-Jui Wong.The objectives of SEAFOMP are to promote (i) co-operation and communication between medical physics organizations in the region; (ii) medical physics and related activities in the region; (iii) the advancement in status and standard of practice of the medical physics profession; (iv) to organize and/or sponsor international and regional conferences, meetings or courses; (v) to collaborate or affiliate with other scientific organizations.SEAFOMP has been organizing a series of congresses to promote scientific exchange and mutual support. The South East Asian Congress of Medical Physics (SEACOMP) series was held respectively in Kuala Lumpur (2001), Bangkok (2003), Kuala Lumpur (2004) and Jakarta (2006). The respective congress themes indicated the emphasis and status of development. The number of participants (countries in parentheses) was encouraging: 110 (17), 150 (16), 220 (23) and 126 (7).In honour of the late Professor John Cameron, an eponymous lecture was established. The inaugural John Cameron Lecture was delivered by Professor Willi Kalender in 2004. His lecture was titled "Recent Developments in Volume CT Scanning".
    Matched MeSH terms: Physics
  2. Woo M, Ng Kh
    Biomed Imaging Interv J, 2008 Jan;4(1):e13.
    PMID: 21614306 MyJurnal DOI: 10.2349/biij.4.1.e13
    Medical physics is a relatively small professional community, usually with a scarcity of expertise that could greatly benefit students entering the field. However, the reach of the profession can span great geographical distances, making the training of students a difficult task. In addition to the requirement of training new students, the evolving field of medical physics, with its many emerging advanced techniques and technologies, could benefit greatly from ongoing continuing education as well as consultation with experts.Many continuing education courses and workshops are constantly being offered, including many web-based study courses and virtual libraries. However, one mode of education and communication that has not been widely used is the real-time interactive process. Video-based conferencing systems do exist, but these usually require a substantial amount of effort and cost to set up.The authors have been working on promoting the ever-expanding capability of the Internet to facilitate the education of medical physics to students entering the field. A pilot project has been carried out for six years and reported previously. The project is a collaboration between the Department of Medical Physics at the Toronto Odette Cancer Centre in Canada and the Department of Biomedical Imaging at the University of Malaya in Malaysia. Since 2001, medical physics graduate students at the University of Malaya have been taught by lecturers from Toronto every year, using the Internet as the main tool of communication.The pilot study explored the different methods that can be used to provide real-time interactive remote education, and delivered traditional classroom lectures as well as hands-on workshops.Another similar project was started in 2007 to offer real-time teaching to a class of medical physics students at Wuhan University in Hubei, China. There are new challenges as well as new opportunities associated with this project. By building an inventory of tools and experiences, the intent is to broaden the real-time teleteaching method to serve a wide community so that future students entering the field can have efficient access to high-quality education that will benefit the profession in the long term.
    Matched MeSH terms: Physics
  3. Tamrin KF, Moghadasi K, Jalil MH, Sheikh NA, Mohamaddan S
    Materials (Basel), 2021 Apr 16;14(8).
    PMID: 33923675 DOI: 10.3390/ma14082009
    This study discloses a method for painting artwork using a CO2 laser. The continuous-wave laser beam, at a predetermined heat flux and a predetermined number of laser beam passes, mixes and displaces the plurality of colored polymer-based compositions, respectively, by way of melting and vaporizing them. Experiments showed a great accuracy of colors and designed patterns between the computer aided design (CAD) drawing and what was achieved after laser discoloration. It was found that lower values of power and speed provide sufficient energy and time to make a melt pool of colors and cause their vaporization from the surface. A detailed numerical simulation was performed to obtain a detailed understanding of the physics of laser interaction with paint using ABAQUS software. The comparative analysis indicated that the top layer of paint (including yellow and green colors) melted upon increasing cutting speed and employing one laser pass. For blue and red paints, two passes of lasers are required; in the case of red color, lower laser speed is also necessary to intensify the heat. This method can be applied for making art designs on each surface color because it is based on melting and vaporization using a laser.
    Matched MeSH terms: Physics
  4. Aman S, Khan I, Ismail Z, Salleh MZ
    Neural Comput Appl, 2018;30(3):789-797.
    PMID: 30100679 DOI: 10.1007/s00521-016-2688-7
    Impacts of gold nanoparticles on MHD Poiseuille flow of nanofluid in a porous medium are studied. Mixed convection is induced due to external pressure gradient and buoyancy force. Additional effects of thermal radiation, chemical reaction and thermal diffusion are also considered. Gold nanoparticles of cylindrical shape are considered in kerosene oil taken as conventional base fluid. However, for comparison, four other types of nanoparticles (silver, copper, alumina and magnetite) are also considered. The problem is modeled in terms of partial differential equations with suitable boundary conditions and then computed by perturbation technique. Exact expressions for velocity and temperature are obtained. Graphical results are mapped in order to tackle the physics of the embedded parameters. This study mainly focuses on gold nanoparticles; however, for the sake of comparison, four other types of nanoparticles namely silver, copper, alumina and magnetite are analyzed for the heat transfer rate. The obtained results show that metals have higher rate of heat transfer than metal oxides. Gold nanoparticles have the highest rate of heat transfer followed by alumina and magnetite. Porosity and magnetic field have opposite effects on velocity.
    Matched MeSH terms: Physics
  5. Lau S, Ng KH, Abdul Aziz YF
    Br J Radiol, 2016 Oct;89(1066):20160258.
    PMID: 27452264 DOI: 10.1259/bjr.20160258
    OBJECTIVE: To investigate the sensitivity and robustness of a volumetric breast density (VBD) measurement system to errors in the imaging physics parameters including compressed breast thickness (CBT), tube voltage (kVp), filter thickness, tube current-exposure time product (mAs), detector gain, detector offset and image noise.

    METHODS: 3317 raw digital mammograms were processed with Volpara(®) (Matakina Technology Ltd, Wellington, New Zealand) to obtain fibroglandular tissue volume (FGV), breast volume (BV) and VBD. Errors in parameters including CBT, kVp, filter thickness and mAs were simulated by varying them in the Digital Imaging and Communications in Medicine (DICOM) tags of the images up to ±10% of the original values. Errors in detector gain and offset were simulated by varying them in the Volpara configuration file up to ±10% from their default values. For image noise, Gaussian noise was generated and introduced into the original images.

    RESULTS: Errors in filter thickness, mAs, detector gain and offset had limited effects on FGV, BV and VBD. Significant effects in VBD were observed when CBT, kVp, detector offset and image noise were varied (p 

    Matched MeSH terms: Physics
  6. Kiani MJ, Harun FK, Ahmadi MT, Rahmani M, Saeidmanesh M, Zare M
    Nanoscale Res Lett, 2014;9(1):371.
    PMID: 25114659 DOI: 10.1186/1556-276X-9-371
    Graphene is an attention-grabbing material in electronics, physics, chemistry, and even biology because of its unique properties such as high surface-area-to-volume ratio. Also, the ability of graphene-based materials to continuously tune charge carriers from holes to electrons makes them promising for biological applications, especially in lipid bilayer-based sensors. Furthermore, changes in charged lipid membrane properties can be electrically detected by a graphene-based electrolyte-gated graphene field effect transistor (GFET). In this paper, a monolayer graphene-based GFET with a focus on the conductance variation caused by membrane electric charges and thickness is studied. Monolayer graphene conductance as an electrical detection platform is suggested for neutral, negative, and positive electric-charged membrane. The electric charge and thickness of the lipid bilayer (Q LP and L LP) as a function of carrier density are proposed, and the control parameters are defined. Finally, the proposed analytical model is compared with experimental data which indicates good overall agreement.
    Matched MeSH terms: Physics
  7. Nur Jannah Azman, Wan Mohd Rizlan Wan Idris, Alice Shanthi
    Jurnal Inovasi Malaysia, 2019;2(2):111-122.
    MyJurnal
    Circular 10/2016 issued by UiTM Vice-Chancellor’s office comprises a clear guideline for 2017 Strategic Budget Planning. The guidelines can help the Head of PTJ’s to plan and take necessary cost effective measures to reduce on utility expenditure especially to counter the rising monthly electricity bills related to the use of air conditioners on campuses. Looking at the figures drawn from the energy management office in UiTM Negeri Sembilan Branch, UiTM Kuala Pilah campus has spent an average of RM153, 028.88 monthly in 2016. As of August 2016, the cost of electricity consumption in UiTM Kuala Pilah has reached RM1,224,231.03. This amount has surpassed the overall approved allocation of RM 800,000.00 for 2016 electricity bill. In order to reduce spending and encourage saving, as well as responding to the ‘Energy Savings Campaign’ held at the campus level, various efforts have been taken at the departmental levels. One of the innovative products that came about from the campaign is the ‘Smartfan’ project pioneered by the Physics and Materials Science Unit. The main objective of this project is the production of a “smartfan” or a mini air conditioner which is a simple, cost-effective and an energy saving device. In addition, products and ideas from the campaign can be piloted and taken to innovative, inventions and design contests at national and international levels.
    Matched MeSH terms: Physics
  8. Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Bergauer T, Dragicevic M, et al.
    Eur Phys J C Part Fields, 2020;80(8):752.
    PMID: 32852485 DOI: 10.1140/epjc/s10052-020-8168-3
    A data sample of events from proton-proton collisions with at least two jets, and two isolated same-sign or three or more charged leptons, is studied in a search for signatures of new physics phenomena. The data correspond to an integrated luminosity of

    137




    fb


    -
    1




    at a center-of-mass energy of

    13

    TeV

    , collected in 2016-2018 by the CMS experiment at the LHC. The search is performed using a total of 168 signal regions defined using several kinematic variables. The properties of the events are found to be consistent with the expectations from standard model processes. Exclusion limits at 95% confidence level are set on cross sections for the pair production of gluinos or squarks for various decay scenarios in the context of supersymmetric models conserving or violating R parity. The observed lower mass limits are as large as

    2.1

    TeV

    for gluinos and

    0.9

    TeV

    for top and bottom squarks. To facilitate reinterpretations, model-independent limits are provided in a set of simplified signal regions.
    Matched MeSH terms: Physics
  9. Ali NA, Sazelee N, Yahya MS, Ismail M
    Front Chem, 2020;8:457.
    PMID: 32656179 DOI: 10.3389/fchem.2020.00457
    In this study, the modification of the desorption behavior of LiAlH4 by the addition of K2NbF7 was explored for the first time. The addition of K2NbF7 causes a notable improvement in the desorption behavior of LiAlH4. Upon the addition of 10 wt.% of K2NbF7, the desorption temperature of LiAlH4 was significantly lowered. The desorption temperature of the LiAlH4 + 10 wt.% K2NbF7 sample was lowered to 90°C (first-stage reaction) and 149°C (second-stage reaction). Enhancement of the desorption kinetics performance with the LiAlH4 + 10 wt.% K2NbF7 sample was substantiated, with the composite sample being able to desorb hydrogen 30 times faster than did pure LiAlH4. Furthermore, with the presence of 10 wt.% K2NbF7, the calculated activation energy values for the first two desorption stages were significantly reduced to 80 and 86 kJ/mol; 24 and 26 kJ/mol lower than the as-milled LiAlH4. After analysis of the X-ray diffraction result, it is believed that the in situ formation of NbF4, LiF, and K or K-containing phases that appeared during the heating process promoted the amelioration of the desorption behavior of LiAlH4 with the addition of K2NbF7.
    Matched MeSH terms: Physics
  10. Ee, S.C., Bakar, J., Kharidah, M., Dzulkifly, M.H., Noranizan, A.
    MyJurnal
    The physico-chemical properties of spray-dried pitaya peel powders kept at accelerated (45 ± 2°C) and room temperature (28 ± 2°C) for 14 weeks and 6 months, respectively were evaluated. Changes in physico-chemical properties of the peel powder were used as indicators of stability, while changes of the betacyanin pigment retention was used to calculate the shelf-life of the powder. Storage temperatures significantly (p < 0.05) affected all the studied parameters and Hunter a value had the most significant change. The pigment retention of peel powder was approximately 87% at 45°C and 89% at room temperature storage. Degradation of betacyanin pigment in the powder followed the first order reaction kinetics with the half-life (t1/2) of approximately 76 weeks at 45°C and 38 months at 28°C. The spray-dried pitaya peel powder had a solubility of 87 to 92% and low in powder hygroscopicity. The final Aw of the powder did not exceed 0.6 for both storage temperatures.
    Matched MeSH terms: Physics
  11. Callen E, Scadron M
    Science, 1978 Jun 2;200(4345):1018-22.
    PMID: 17740674
    The Physics Interviewing Project assists graduate physics departments in evaluating foreign applicants. Supported by some 20 universities, two interviewers, both working scientists, travel abroad and interview students individually for about 1 hour each. Prospective teaching assistants are rated on physics knowledge, problem-solving ability, and English language proficiency. Ratings on all interviewees are sent to all supporting schools and other schools as requested. The Project aids able students from countries that have no physics Ph.D. programs (Indonesia, Malaysia, Thailand) to obtain assistantships and Ph.D.'s abroad, assists in the technological development of those countries, and helps U.S. schools in selecting the most promising foreign candidates. A similar program should be beneficial in other sciences.
    Matched MeSH terms: Physics
  12. Razak Mohd Ali Lee, Khairul Anwar Mohamad, Katsuyoshi, Hamasaki
    MyJurnal
    We put attention on Intrinsic Josephson Junction (IJJ) to study the fundamental physic for device applications. Convenient self-flux method was used to grow BSCCO single crystals. We investigated the lid effect to examine the single crystal growth of high TC (Critical Temperature). We found that for the crystal growth with no lid, two stage transitions of TC ≅ 61 K and 77 K were observed. While for the crystal growth with lid, the BSCCO has TC ≅ 80K, ΔTC = 10K and approximately average size5x2mm 2 . When we increased weight of lid, the single crystal have increased to TC =80K, ΔTC = 4K and the typical size was ≅7x3mm 2 . TC and the crystal growth show a tendency to increase by the effect of the lid. From observed quasi-particle characteristics, c-axis direction changed from semiconductor to intrinsic Josephson characteristic with decreasing temperature.
    Matched MeSH terms: Physics
  13. Tan K, Heo S, Foo M, Chew IM, Yoo C
    Sci Total Environ, 2019 Feb 10;650(Pt 1):1309-1326.
    PMID: 30308818 DOI: 10.1016/j.scitotenv.2018.08.402
    Nanocellulose, a structural polysaccharide that has caught tremendous interests nowadays due to its renewability, inherent biocompatibility and biodegradability, abundance in resource, and environmental friendly nature. They are promising green nanomaterials derived from cellulosic biomass that can be disintegrated into cellulose nanofibrils (CNF) or cellulose nanocrystals (CNC), relying on their sensitivity to hydrolysis at the axial spacing of disordered domains. Owing to their unique mesoscopic characteristics at nanoscale, nanocellulose has been widely researched and incorporated as a reinforcement material in composite materials. The world has been consuming the natural resources at a much higher speed than the environment could regenerate. Today, as an uprising candidate in soft condensed matter physics, a growing interest was received owing to its unique self-assembly behaviour and quantum size effect in the formation of three-dimensional nanostructured material, could be utilised to address an increasing concern over global warming and environmental conservation. In spite of an emerging pool of knowledge on the nanocellulose downstream application, that was lacking of cross-disciplinary study of its role as a soft condensed matter for food, water and energy applications toward environmental sustainability. Here we aim to provide an insight for the latest development of cellulose nanotechnology arises from its fascinating physical and chemical characteristic for the interest of different technology holders.
    Matched MeSH terms: Physics
  14. Aziz SB, B Marif R, Brza MA, Hamsan MH, Kadir MFZ
    Polymers (Basel), 2019 Oct 16;11(10).
    PMID: 31623158 DOI: 10.3390/polym11101694
    In the current paper, ion transport parameters in poly (vinyl alcohol) (PVA) based solid polymer electrolyte were examined using Trukhan model successfully. The desired amount of lithium trifluoromethanesulfonate (LiCF3SO3) was dissolved in PVA host polymer to synthesis of solid polymer electrolytes (SPEs). Ion transport parameters such as mobility (μ), diffusion coefficient (D), and charge carrier number density (n) are investigated in detail using impedance spectroscopy. The data results from impedance plots illustrated a decrement of bulk resistance with an increase in temperature. Using electrical equivalent circuits (EEC), electrical impedance plots (ZivsZr) are fitted at various temperatures. The results of impedance study demonstrated that the resistivity of the sample decreases with increasing temperature. The decrease of resistance or impedance with increasing temperature distinguished from Bode plots. The dielectric constant and dielectric loss values increased with an increase in temperature. The loss tangent peaks shifted to higher frequency region and the intensity increased with an increase in temperature. In this contribution, ion transport as a complicated subject in polymer physics is studied. The conductivity versus reciprocal of temperature was found to obey Arrhenius behavior type. The ion transport mechanism is discussed from the tanδ spectra. The ion transport parameters at ambient temperature are found to be 9 × 10-8 cm2/s, 0.8 × 1017 cm-3, and 3 × 10-6 cm2/Vs for D, n, andμ respectively. All these parameters have shown increasing as temperature increased. The electric modulus parameters are studied in an attempt to understand the relaxation dynamics and to clarify the relaxation process and ion dynamics relationship.
    Matched MeSH terms: Physics
  15. Bradley DA, Nawi SNM, Khandaker MU, Almugren KS, Sani SFA
    Appl Radiat Isot, 2020 Jul;161:109168.
    PMID: 32321700 DOI: 10.1016/j.apradiso.2020.109168
    Present work concerns polymer pencil-lead graphite (PPLG) and the potential use of these in elucidating irradiation-driven structural alterations. The study provides detailed analysis of radiation-induced structural interaction changes and the associated luminescence that originates from the energy absorption. Thermally stimulated emission from the different occupied defect energy levels reflects the received radiation dose, different for the different diameter PPLGs. The PPLG samples have been exposed to photon irradiation, specifically x-ray doses ranging from 1 to 10 Gy, extended to 30-200 Gy through use of a60Co gamma-ray source. Trapping parameters such as order of kinetics, activation energy and frequency factor are estimated using Chen's peak-shape method for a fixed-dose of 30 Gy. X-ray diffractometry was used to characterize the crystal structure of the PPLG, the aim being to identify the degree of structural order, atomic spacing and lattice constants of the various irradiated PPLG samples. The mean atomic spacing and degree of structural order for the different diameter PPLG are found to be 0.3332 nm and 26.6° respectively. Photoluminescence spectra from PPLG arising from diode laser excitation at 532 nm consist of two adjacent peaks, 602 nm (absorption) and 1074 nm (emission), with mean energy band gap values within the range 1.113-1.133 eV.
    Matched MeSH terms: Physics
  16. Abdullah MNS, Karpudewan M, Tanimale BM
    Trends Neurosci Educ, 2021 09;24:100159.
    PMID: 34412861 DOI: 10.1016/j.tine.2021.100159
    Advances in neuroscience studies have brought new insights into the development of Executive Functions (EFs) of the brain and its influence on understanding science concepts. This study was conducted to examine the relationships between three main components of EF: working memory, inhibition, set-shifting and understanding of Force concepts among adolescents. This study also investigated how gender mediates the relationships between the components of EF and understanding. Cambridge Neuropsychological Test Automated Battery was used to assess students' level of working memory, inhibition, and set-shifting. The Force Concept Test measured students understanding. Smart-PLS analysis was employed to examine the relationships between the three components of EF and understanding; and how gender mediates the relationships. The result reveals that working memory significantly relates to students' understanding of Force concepts in a positive direction. On the contrary, both set-shifting and inhibition exhibit non-significant relationships. The findings also demonstrate that gender does not significantly mediate the relationships. The findings are useful for Physics teachers to guide them through designing the curriculum and opting for an appropriate pedagogical strategy considering the role of the components of EF for teaching the lessons on Force.
    Matched MeSH terms: Physics
  17. Prasetyono TOH, Adhistana P
    Malays J Med Sci, 2019 Mar;26(2):66-76.
    PMID: 31447610 DOI: 10.21315/mjms2019.26.2.8
    Background: This study aimed to measure the least initial and maintenance forces of syringe and needle combinations to provide a reference for local anesthetic injection.

    Methods: An experimental study was conducted in our Physics Laboratory during September 2015. A series of syringes sized 1 mL, 3 mL, 5 mL, 10 mL and 20 mL were paired with the original needles, 27G, 27G spinal and 30G. Each combination was tested three times using a compression testing Instron 5940 Series to measure initial and maintenance forces. Statistical analysis was performed using One-way ANOVA.

    Results: The lowest initial force was shown by the combination of 1 mL syringe and 27G spinal needle. However, the 1 mL syringe showed no significant difference across the needles [F(3, 8) = 3.545; P < 0.068]. The original and 27G needle showed mean difference 0.28 (95%CI: -0.19, 0.75; P = 0.420). The lowest maintenance force was measured in the combination of 1 mL syringe and its original 26G needle. On the contrary, both the highest initial and maintenance forces were shown by the combination of 10 mL syringe and 30G needle.

    Conclusion: The 1 mL syringe with original 26G needle shows the best combination.

    Matched MeSH terms: Physics
  18. Alanazi A, Alkhorayef M, Alzimami K, Jurewicz I, Abuhadi N, Dalton A, et al.
    Appl Radiat Isot, 2016 Nov;117:106-110.
    PMID: 26777569 DOI: 10.1016/j.apradiso.2016.01.001
    Graphite ion chambers and semiconductor diode detectors have been used to make measurements in phantoms but these active devices represent a clear disadvantage when considered for in vivo dosimetry. In such circumstance, dosimeters with atomic number similar to human tissue are needed. Carbon nanotubes have properties that potentially meet the demand, requiring low voltage in active devices and an atomic number similar to adipose tissue. In this study, single-wall carbon nanotubes (SWCNTs) buckypaper has been used to measure the beta particle dose deposited from a strontium-90 source, the medium displaying thermoluminescence at potentially useful sensitivity. As an example, the samples show a clear response for a dose of 2Gy. This finding suggests that carbon nanotubes can be used as a passive dosimeter specifically for the high levels of radiation exposures used in radiation therapy. Furthermore, the finding points towards further potential applications such as for space radiation measurements, not least because the medium satisfies a demand for light but strong materials of minimal capacitance.
    Matched MeSH terms: Health Physics/instrumentation; Health Physics/methods
  19. Woo MK, Ng KH
    J Med Internet Res, 2003 Jan-Mar;5(1):e3.
    PMID: 12746208
    Medical physics is a relatively small community but it spans great geographical distances, usually with a scarcity of experts whose expertise could greatly benefit students entering into the field. In addition there are many software systems for which an interactive education method would be most advantageous.
    Matched MeSH terms: Nuclear Physics/education*; Nuclear Physics/methods
  20. Nee CH, Yap SL, Tou TY, Chang HC, Yap SS
    Sci Rep, 2016 Sep 23;6:33966.
    PMID: 27659184 DOI: 10.1038/srep33966
    Carbon nanomaterials exhibit novel characteristics including enhanced thermal, electrical, mechanical, and biological properties. Nanodiamonds; first discovered in meteorites are found to be biocompatible, non-toxic and have distinct optical properties. Here we show that nanodiamonds with the size of <5 nm are formed directly from ethanol via 1025 nm femtosecond laser irradiation. The absorption of laser energy by ethanol increased non-linearly above 100 μJ accompanied by a white light continuum arises from fs laser filamentation. At laser energy higher than 300 μJ, emission spectra of C, O and H in the plasma were detected, indicating the dissociation of C2H5OH. Nucleation of the carbon species in the confined plasma within the laser filaments leads to the formation of nanodiamonds. The energy dependence and the roles of the nonlinear phenomenon to the formation of homogeneous nanodiamonds are discussed. This work brings new possibility for bottom-up nanomaterials synthesis based on nano and ultrafast laser physics.
    Matched MeSH terms: Physics
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