Displaying publications 1 - 20 of 62 in total

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  1. 11-Methyl-12a-phenyl-9a,12a-dihydrophenanthro[9',10:5,6][1,4]dioxino[2,3-d]thiazole
    Usman A, Razak IA, Fun HK, Chantrapromma S, Zhang Y, Xu JH
    Acta Crystallogr C, 2002 Sep;58(Pt 9):o543-4.
    PMID: 12205382
    In the title compound, C(24)H(17)NO(2)S, the dioxine and thiazoline rings are distorted from planarity towards a half-chair and an envelope conformation, respectively. The configurations of the dioxine ring, the thiazoline ring and the attached phenyl ring are conditioned by the sp(3) state of the two bridgehead C atoms. The phenanthrene system is nearly coplanar with the dioxine ring, while the attached phenyl ring is orthogonal to the thiazoline ring.
    Matched MeSH terms: Aircraft
  2. 2-Hydroxy-3-(4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridin-5-ium-4-yl)benzoate monohydrate
    Usman A, Nayar CR, Unnikrishnan PA, Sreeja PB, Prathapachandra Kurup MR, Fun HK
    Acta Crystallogr C, 2002 Dec;58(Pt 12):o724-6.
    PMID: 12466626
    The title molecule, C(13)H(13)N(3)O(3).H(2)O, is in the form of a monohydrated zwitterion. The tetrahydropyridinium ring adopts an envelope conformation and is nearly coplanar with the plane of the imidazoline ring. The water solvate molecule plays an important role as a bridge between zwitterions, forming molecular chains running along the c direction, which are interconnected by N-H.O hydrogen bonds into molecular ribbons. The crystal packing is further stabilized by another N-H.O and one O-H.N hydrogen bond, which interconnect the molecular ribbons.
    Matched MeSH terms: Aircraft
  3. Fulltext A Finite Element Model for Dynamic Analysis of Triple-Layer Composite Plates with Layers Connected by Shear Connectors Subjected to Moving Load
    Nguyen HN, Nguyen TY, Tran KV, Tran TT, Nguyen TT, Phan VD, et al.
    Materials (Basel), 2019 Feb 16;12(4).
    PMID: 30781542 DOI: 10.3390/ma12040598
    Triple-layered composite plates are created by joining three composite layers using shear connectors. These layers, which are assumed to be always in contact and able to move relatively to each other during deformation, could be the same or different in geometric dimensions and material. They are applied in various engineering fields such as ship-building, aircraft wing manufacturing, etc. However, there are only a few publications regarding the calculation of this kind of plate. This paper proposes novel equations, which utilize Mindlin's theory and finite element modelling to simulate the forced vibration of triple-layered composite plates with layers connected by shear connectors subjected to a moving load. Moreover, a Matlab computation program is introduced to verify the reliability of the proposed equations, as well as the influence of some parameters, such as boundary conditions, the rigidity of the shear connector, thickness-to-length ratio, and the moving load velocity on the dynamic response of the composite plate.
    Matched MeSH terms: Aircraft
  4. Fulltext A Novel Eddy Current Testing Error Compensation Technique Based on Mamdani-Type Fuzzy Coupled Differential and Absolute Probes
    Abdalla AN, Ali K, Paw JKS, Rifai D, Faraj MA
    Sensors (Basel), 2018 Jun 30;18(7).
    PMID: 29966367 DOI: 10.3390/s18072108
    Eddy current testing (ECT) is an accurate, widely used and well-understood inspection technique, particularly in the aircraft and nuclear industries. The coating thickness or lift-off will influence the measurement of defect depth on pipes or plates. It will be an uncertain decision condition whether the defects on a workpiece are cracks or scratches. This problem can lead to the occurrence of pipe leakages, besides causing the degradation of a company’s productivity and most importantly risking the safety of workers. In this paper, a novel eddy current testing error compensation technique based on Mamdani-type fuzzy coupled differential and absolute probes was proposed. The general descriptions of the proposed ECT technique include details of the system design, intelligent fuzzy logic design and Simulink block development design. The detailed description of the proposed probe selection, design and instrumentation of the error compensation of eddy current testing (ECECT) along with the absolute probe and differential probe relevant to the present research work are presented. The ECECT simulation and hardware design are proposed, using the fuzzy logic technique for the development of the new methodology. The depths of the defect coefficients of the probe’s lift-off caused by the coating thickness were measured by using a designed setup. In this result, the ECECT gives an optimum correction for the lift-off, in which the reduction of error is only within 0.1% of its all-out value. Finally, the ECECT is used to measure lift-off in a range of approximately 1 mm to 5 mm, and the performance of the proposed method in non-linear cracks is assessed.
    Matched MeSH terms: Aircraft
  5. Fulltext A study of patients admitted to Miri Hospital, Sarawak, by airborne medical evacuation
    Kiyu Dawie A
    Med J Malaysia, 1986 Jun;41(2):123-33.
    PMID: 3821607
    From January 1980 to December 1982, there were 222 MEDEVAC patients admitted to Mid Hospital, out of whom 206 had their case notes available for this study. The median age of the 206 patients MEDEVAC was 24.5 years and the male to female ratio was 1.2 : 1. The Kenyah, Iban, Punans, Kelabit, Kayan and Murut ethnic groups contributed most of the cases. There was some seasonal variation in the number of MEDEVAC done, the high months being July and December and the low periods in May/June and October/November. Most of the MEDEVAC were requested by ground staff at the remote rural clinics and also district hospitals. The median duration of stay of the patients was 9.7 days. The top five causes for MEDEVAC were: bronchopneumonia; accidental falls; gastroenteritis; peptic ulcers; and appendicitis. 7.8% of the MEDEVAC died in hospital. The management of cases ranged from conservative management to blood transfusions to surgical interventions. Based on the criteria set, 63.6% of the MEDEVAC were considered justified.
    Matched MeSH terms: Aircraft*
  6. Fulltext Airborne measurements of organic bromine compounds in the Pacific tropical tropopause layer
    Navarro MA, Atlas EL, Saiz-Lopez A, Rodriguez-Lloveras X, Kinnison DE, Lamarque JF, et al.
    Proc Natl Acad Sci U S A, 2015 Nov 10;112(45):13789-93.
    PMID: 26504212 DOI: 10.1073/pnas.1511463112
    Very short-lived brominated substances (VSLBr) are an important source of stratospheric bromine, an effective ozone destruction catalyst. However, the accurate estimation of the organic and inorganic partitioning of bromine and the input to the stratosphere remains uncertain. Here, we report near-tropopause measurements of organic brominated substances found over the tropical Pacific during the NASA Airborne Tropical Tropopause Experiment campaigns. We combine aircraft observations and a chemistry-climate model to quantify the total bromine loading injected to the stratosphere. Surprisingly, despite differences in vertical transport between the Eastern and Western Pacific, VSLBr (organic + inorganic) contribute approximately similar amounts of bromine [∼6 (4-9) parts per trillion] [corrected] to the stratospheric input at the tropical tropopause. These levels of bromine cause substantial ozone depletion in the lower stratosphere, and any increases in future abundances (e.g., as a result of aquaculture) will lead to larger depletions.
    Matched MeSH terms: Aircraft
  7. Fulltext An alternative efficient technique for thin tooth sectioning
    Babar, Muneer Gohar, Gonzalez, Ma Angela
    International e-Journal of Science, Medicine & Education, 2011;5(1):27-30.
    MyJurnal
    Background: The importance of tooth sectioning is realized in disasters such as earthquake, airplane crash investigation, terror, micro leakage studies, age estimation etc. The objective of this study was to develop a simple method to make thin sections (approximately 100 mm) from freshly extracted teeth.

    Methods: One hundred and twenty human premolars recently extracted for orthodontic purpose were used for this study. The teeth were stored in 0.5% chorlaramine for 2 weeks and were not allowed to dry at any stage of the experiment. The teeth were thoroughly washed in distilled water teeth and then were sectioned buccolingually from crown to the root portion.

    Results: A detailed embedding-cutting-mounting procedure is described. The prepared thin ground sections were then examined under a Polarised light microscope for the enamel and the dentine, as well as the caries lesions can clearly be distinguished.

    Conclusion: This is an effective and efficient method for preparation of ground sections in which the hard tissue details are preserved.
    Matched MeSH terms: Aircraft
  8. Fulltext Augmentation of the Delamination Factor in Drilling of Carbon Fibre-Reinforced Polymer Composites (CFRP)
    Ahmad Sobri S, Whitehead D, Mohamed M, Mohamed JJ, Mohamad Amini MH, Hermawan A, et al.
    Polymers (Basel), 2020 Oct 23;12(11).
    PMID: 33114223 DOI: 10.3390/polym12112461
    Carbon fibre-reinforced polymer (CFRP) composite materials play an increasingly important role in modern manufacturing, and they are among the more prominent materials used in aircraft manufacturing today. However, CFRP is highly prone to delamination and other damage when drilled due to it being extremely strong with a good strength-to-weight ratio and high thermal conductivity. Because of this problem and CFRP's growing importance in aircraft manufacture, research has focused on the entry and exit holes as indicators of damage occurrence during drilling of screws, rivets, and other types of holes. The inside of the hole was neglected in past research and a proper way to quantify the internal side of a hole by combining the entry and exit hole should be included. To fill this gap and improve the use of CFRP, this paper reports a novel technique to measure the holes by using the extension of the adjusted delamination factor (SFDSR) for drilling thick CFRP composites in order to establish the influence of machining input variables on key output measures, i.e., delamination and other damages. The experimental results showed a significant difference in interpretation of the damage during the analysis. Improvement was made by providing better perspectives of identifying hole defects.
    Matched MeSH terms: Aircraft
  9. Bis[N,N-bis(2-hydroxyethyl)dithiocarbamato]dimethyltin(IV)
    Ng SW, Yang Farina AA, Othman AH, Baba I, Sivakumar K, Fun HK
    Acta Crystallogr C, 2000 Mar 15;56(Pt 3):E84-5.
    PMID: 15263206
    The title compound, [Sn(CH(3))(2)(C(5)H(10)NO(2)S(2))(2)], has crystallographic mirror symmetry (C-Sn-C on mirror plane) and the coordination polyhedron around the Sn atom is a tetrahedron [C-Sn-C 139.3 (2) degrees and S-Sn-S 82.3 (1) degrees ] distorted towards a skew-trapezoidal bipyramid owing to an intramolecular Sn.S contact [3.0427 (6) A]. The molecules are linked into a linear chain by intermolecular O-H.O hydrogen bonds [O.O 2.646 (3) A].
    Matched MeSH terms: Aircraft
  10. Can stature be estimated from tooth crown dimensions? A study in a sample of South-East Asians
    Hossain MZ, Munawar KM, Rahim ZH, Bakri MM
    Arch Oral Biol, 2016 Apr;64:85-91.
    PMID: 26803673 DOI: 10.1016/j.archoralbio.2016.01.001
    Stature estimation is an important step during medico-legal and forensic examination. Difficulty arises when highly decomposed and mutilated dead bodies with fragmentary remains are brought for forensic identification like in mass disaster or airplane crash. The body remains could be just a jaw with some teeth. The objective of this study was to explore if the stature of an individual can be determined from the tooth crown dimensions.
    Matched MeSH terms: Aircraft
  11. Fulltext Casualty evacuation by helicopter in Malaya
    HARVEY EB
    Br Med J, 1951 Sep 01;2(4730):542-4.
    PMID: 14869641
    Matched MeSH terms: Aircraft*
  12. Combinational system of a truncated ball lens and a hyperbolic lens for collimating a highly divergent source
    Chen LC, Low AL, Chien SF
    Appl Opt, 2004 Dec 10;43(35):6380-3.
    PMID: 15617273
    We propose the use of a truncated ball lens in a collimating system to transform a spherical wave from a highly divergent source into a plane wave. The proposed scheme, which incorporates a hyperbolic lens, is discussed, and the overall system is found to have a large acceptance angle and to be free of spherical aberration. Diffraction and polarization effects are neglected, as well as skew rays.
    Matched MeSH terms: Aircraft
  13. Contactless Visualization of Latent Fingerprints on Nonporous Curved Surfaces of Circular Cross Section-A Statistical Evaluation on the Materials as Plane Mirror
    Low WZ, Khoo BE, Abdullah AFLB
    J Forensic Sci, 2018 Jul;63(4):1092-1098.
    PMID: 29178492 DOI: 10.1111/1556-4029.13702
    A new contactless technique for latent fingerprint visualization on nonporous curved surfaces of circular cross section was introduced by Low et al. (1). The technique utilizes a plane mirror to convey the light rays toward the inspected surfaces for latent fingerprint visualization. This research activity came up as an extension of the previous study which utilized an aluminum plate as the plane mirror to illuminate the inspected surfaces. Dulling spray was used to increase the diffuse component of the reflective aluminum plate. However, the amount of dulling spray will affect the uniformity of the illumination on the inspected curved surfaces. In this study, a study on the new materials for the plane mirror was carried out. Coated aluminum, opal, and ground glass diffusers were selected as the new materials. The performance of the new materials was compared to the aluminum based on the quality of the captured images on various nonporous cylindrical surfaces. A statistical approach known as randomized complete block design was used to design the experiment. The quality of the captured images was obtained using Spectral Image Validation and Verification. Two-way analysis of variance and Fisher's least significant difference test were used to analyze the quality of the images. From the results of the statistical analysis, coated aluminum has the best performance compared to aluminum, opal, and ground glass diffusers.
    Matched MeSH terms: Aircraft
  14. Fulltext CropCam UAV for land use/land cover mapping over Penang Island, Malaysia
    Faez M. Hassan, Lim, H.S., Mat Jafri, M.Z.
    Pertanika Journal of Science & Technology, 2011;19(3):69-76.
    MyJurnal
    The problem of difficulty in obtaining cloud-free scene at the equatorial region from satellite platforms can be
    overcome by using airborne imagery as an attempt for introducing an economical method of remote sensing
    data; which only requires a digital camera to provide near time data. Forty three digital images were captured
    using a high resolution digital camera model pentax optio A40 (12 megapixels)at a selected location in the same day in Penang Island from a low-altitude flying autopilot aircraft (CropCam) to generate land use/land cover (LULC) map of the test area. The CropCam was flown at an average altitude of 320 meters over the ground while capturing images which were taken during two flying missions for the duration of approximately 15 and 20 minutes respectively. The CropCam was equipped with a digital camera as a sensor to capture the GPS points based digital images according to the present time to ensure the mosaic of the digital images. Forty one images were used in providing a mosaic image of a bigger coverage of area (full panorama). Training samples were collected simultaneously when the CropCam captured the images by using hand held GPS. Supervised classification techniques, such as the maximum likelihood, minimum-to-distance, and parallelepiped were applied to the panoramic image to generate LULC map for the study area. It was found that the maximum likelihood classifier produce superior results and achieved a high degree of accuracy. The results indicated that the CropCam equipped with a high resolution digital camera can be useful and suitable tool for the tropical region, and this technique could reduce the cost and time of acquiring images for LULC mapping.
    Matched MeSH terms: Aircraft
  15. Fulltext Dielectrophoretic separation of cells using 3-D microelectrode
    Zurina Zainal Abidin, Zalini Yunus, Markx, Gerard H.
    Pertanika Journal of Science & Technology, 2009;17(2):-.
    MyJurnal
    The dielectrophoretic (DEP) separation of cell, using microelectrodes structure, has been limited to small scale due to size of the substrate. This work was carried out to extend the capability of microelectrodes system by orientating the microelectrodes in three dimensions (3-D) for larger scale dielectrophoretic separation of microorganism. The designed 3-D separation chamber consists of microelectrodes on two opposing walls. Based on the FEMLAB simulation, the electric field was seen to be generated across the chamber, rather than between adjacent electrodes in the same plane like in the small scale system. This configuration led to a stronger electric field in the bulk medium. The experimental results showed that the 3-D microelectrodes chamber behaved similar to the system with microelectrodes on one wall. The effects of the main parameters such as voltage, frequency and flow rates were similar to that of the systems with all the electrodes on one wall, but on the overall, capture more cells. A gap size between 250 – 500 μm resulted in an electric field which is strong enough to hold cells while giving a reasonable cross sectional area at the same time. Although there is some improvement achieved by 3-D system, it is still not very much, as compared to the small scale system.
    Matched MeSH terms: Aircraft
  16. Fulltext Drone for medical products transportation in maternal healthcare: A systematic review and framework for future research
    Zailani MAH, Sabudin RZAR, Rahman RA, Saiboon IM, Ismail A, Mahdy ZA
    Medicine (Baltimore), 2020 Sep 04;99(36):e21967.
    PMID: 32899033 DOI: 10.1097/MD.0000000000021967
    INTRODUCTION: Medical products transportation has become an important research topic requiring multidisciplinary collaboration among experts in medicine, engineering, and health economics. Current modes of transportation are unable to overcome the limited settings in maternal healthcare, particularly during the event of obstetric emergencies. The drone is a promising medical product aerial transportation (MedART) that holds an enormous potential for delivery of medical supplies in the healthcare system. We conducted a systematic review to examine scientific evidence of positive impact of drone transportation on maternal health.

    METHODS: The following electronic databases were searched from inception to July 2019: ScienceDirect, PubMed, and EMBASE. The report was made in accordance with the principles of PRISMA guidelines. The search terms used were related to drones including unmanned aerial vehicle (UAV) and unmanned aerial system (UAS), and related to obstetric/maternal including obstetric emergencies and postpartum hemorrhage. Studies were selected if the intervention used were drones, and if any direct or indirect maternal health indicators were reported. Meta-analysis was not done throughout the study in view of the anticipated heterogeneity of each study.

    RESULTS: Our initial search yielded a total of 244 relevant publications, from which 236 were carried forward for a title and abstract screening. After careful examination, only two were included for systematic synthesis. Among the reasons for exclusion were irrelevance to maternal health purpose, and irrelevance to drone applications in healthcare. An updated search yielded one additional study that was also included. Overall, two studies assessed drones for blood products delivery, and one study used drones to transport blood samples.

    CONCLUSION: A significant deficiency was found in the number of reported studies analyzing mode of medical products transportation and adaptation of drones in maternal healthcare. Future drone research framework should focus on maternal healthcare-specific drone applications in order to reap benefits in this area.

    Matched MeSH terms: Aircraft/instrumentation*
  17. Fulltext Effect of Printing Parameters on Tensile, Dynamic Mechanical, and Thermoelectric Properties of FDM 3D Printed CABS/ZnO Composites
    Aw YY, Yeoh CK, Idris MA, Teh PL, Hamzah KA, Sazali SA
    Materials (Basel), 2018 Mar 22;11(4).
    PMID: 29565286 DOI: 10.3390/ma11040466
    Fused deposition modelling (FDM) has been widely used in medical appliances, automobile, aircraft and aerospace, household appliances, toys, and many other fields. The ease of processing, low cost and high flexibility of FDM technique are strong advantages compared to other techniques for thermoelectric polymer composite fabrication. This research work focuses on the effect of two crucial printing parameters (infill density and printing pattern) on the tensile, dynamic mechanical, and thermoelectric properties of conductive acrylonitrile butadiene styrene/zinc oxide (CABS/ZnO composites fabricated by FDM technique. Results revealed significant improvement in tensile strength and Young's modulus, with a decrease in elongation at break with infill density. Improvement in dynamic storage modulus was observed when infill density changed from 50% to 100%. However, the loss modulus and damping factor reduced gradually. The increase of thermal conductivity was relatively smaller compared to the improvement of electrical conductivity and Seebeck coefficient, therefore, the calculated figure of merit (ZT) value increased with infill density. Line pattern performed better than rectilinear, especially in tensile properties and electrical conductivity. From the results obtained, FDM-fabricated CABS/ZnO showed much potential as a promising candidate for thermoelectric application.
    Matched MeSH terms: Aircraft
  18. Fulltext Effect of sea-bottom elasticity on the propagation of acoustic-gravity waves from impacting objects
    Kadri U
    Sci Rep, 2019 Jan 29;9(1):912.
    PMID: 30696934 DOI: 10.1038/s41598-018-37626-z
    Recent analysis of data, recorded on March 8th 2014 at the Comprehensive Nuclear-Test-Ban Treaty Organisation's hydroacoustic stations off Cape Leeuwin Western Australia, and at Diego Garcia, has led to the development of an inverse model for locating impacting objects on the sea surface. The model employs the phase velocity of acoustic-gravity waves that radiate during the impact, and only considers their propagation in the water layer. Here, we address a significant characteristic of acoustic-gravity waves: the ability to penetrate through the sea-bottom, which modifies the propagation speed and thus the arrival time of signals at the hydrophone station. Therefore, we revisit some signals that are associated with the missing Malaysian Aeroplane MH370, and illustrate the role of sea-bottom elasticity on determining impact locations.
    Matched MeSH terms: Aircraft
  19. Fulltext Energy absorption and morphological characteristics of opened-cell green rubber foam at different recycled carbon fiber loading
    Mazliah, M., Noraiham, M., Anisah, A.L., Azrul, Y., Hairul, E.A.M., Jeefferie, A.R., et al.
    Malaysian Journal of Microscopy, 2015;11(1):56-60.
    MyJurnal
    Incineration and disposal of carbon fiber waste from the aircraft industry lead to serious energy consumption and environmental pollution. The use of this waste as reinforcement is a wise approach to appreciate the high performance of the carbon fiber. This study is part of our effort to develop new green rubber foam from recycled carbon fiber prepreg (rCFP) reinforced natural rubber via internal mixer. It is focusing on the effect of different rCFP loading at 1, 3, 5, and 7 parts per hundred rubbers (phr) as reinforcement. The samples were prepared by melt compounding using an internal mixer and expanded via two step heat transfer foaming process. The physical properties of the green rubber foam were characterized and the results were observed to systematically correlate with the impact properties of the foam. The absorbed energy of the foam increases up to 0.3 joules with increasing relative foam density of 0.81 which is associated with the formation of smaller foam cells ~0.68mm and more spherical shape pores.
    Matched MeSH terms: Aircraft
  20. Evolution of civil aeromedical helicopter aviation
    Meier DR, Samper ER
    South. Med. J., 1989 Jul;82(7):885-91.
    PMID: 2665130
    The rapid increase in the use of helicopters for hospital transport during the 1980s is the culmination of several hundred years of military medical innovation. Mass battefield casualties spurred both technologic and medical changes necessary for today's sophisticated helicopter systems in use worldwide, particularly in the United States. The Napoleonic Era and the American Civil War provided the framework for the evolution of today's state-of-the-art emergency medical techniques. The use of airplanes to evacuate the wounded eventually led to using helicopters for rescue missions in World War II. The combat experiences of the United States in Korea, the British in Malaya, and the French in Indochina proved that rotary-wing aircraft were invaluable in reducing battlefield death rates. Any skepticism about the efficacy of helicopter medical evacuation was erased during the Vietnam conflict. As an integral part of the modern battlefield, these specialized aircraft became a necessity. The observations and experience of American servicemen and medical personnel in Vietnam established the foundation for the acceptance of helicopter transport in modern hospital systems.
    Matched MeSH terms: Aircraft/history*
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