Displaying publications 101 - 120 of 1914 in total

Abstract:
Sort:
  1. Development of a statistical model for predicting seat pressure felt level in simulated condition based on direct and anthropometric measurement
    Khamis NK, Deros BM
    J Phys Ther Sci, 2018 Jun;30(6):764-769.
    PMID: 29950761 DOI: 10.1589/jpts.30.764
    [Purpose] The purpose of this study was to investigate the effects of seat pressure distribution measurements based on a specific posture to predict the pressure felt level when seated. [Subjects and Methods] To examine the relationship between body pressure data and the driver's perception, eleven subjects were selected to participate in a simulated driving experiment using a pressure mat as a direct measurement method to measure the seat pan's pressure distribution. The buttock-popliteal length was measured using an anthropometer, and the pressure felt ratings evaluated after the body pressure measurements were recorded. Accordingly, this was then followed by performing statistical analysis using seat pressure measurements, and the buttock-popliteal length as independent variables along with subjective ratings selected of the pressure felt by the drivers' as dependent variables. [Results] The findings of this study suggest that the direct measurements and anthropometric body data are positively correlated with the predictive model thereby confirming the validity of the model with an R2 value of 0.952. [Conclusion] The proposed model is expected to provide a useful reference value for new vehicle drivers by providing the pressure felt level based on direct and body measurements in a specific posture.
    Matched MeSH terms: Pressure
  2. Fulltext Influence of Kenaf fibre orientation effect on the mechanical properties of hybrid structure of Fibre Metal Laminate
    Ng, L.F., Sivakumar, D., Zakaria, K.A., Sivaraos, Bapokutty, O.
    Pertanika Journal of Science & Technology, 2017;25(105):1-8.
    MyJurnal
    Efforts to reduce manufacturing cost and negative environmental impacts have seen the mixture of natural fibre with synthetic fibre in composite structures. However, there are limited studies on the notch effect and fibre orientation on mechanical properties of hybrid fibre metal laminate (FML). In this study, tensile properties of FML with notch and different fibre orientation were investigated. The hybrid FML incorporated with kenaf fibre at the middle layer was compared with FML with three layers of E-glass fibre. Kenaf fibre and E-glass fibre used were in plain woven form. The FML in 2/1 configuration was manufactured through hot press manufacturing method to bond layers of annealed aluminium 5052 to the composite. Tensile test was conducted in a quasi-static manner according to ASTM E8. The results showed FML with three layers of glass fibre exhibited higher tensile strength compared with hybrid FML. However, the introduction of kenaf fibre in hybrid FML reduces the notch and fibre orientation sensitivity compared with glass fibre reinforced FML.
    Matched MeSH terms: Pressure
  3. Numerical analysis of flow distribution behavior in a proton exchange membrane fuel cell
    Lim BH, Majlan EH, Daud WRW, Rosli MI, Husaini T
    Heliyon, 2018 Oct;4(10):e00845.
    PMID: 30338304 DOI: 10.1016/j.heliyon.2018.e00845
    The flow distribution of a proton exchange membrane fuel cell within a manifold plays an important role on its performance. This study presents a numerical analysis of the flow distribution behavior within different manifold configurations. A two-dimensional model with 75 cells was employed to study the flow behavior. The variation in the stoichiometry and number of cells was also studied. Three different flow configurations were considered with different numbers of flow inlets and outlets. The flow characteristics, such as the pressure and velocity variations in the manifold and cells, were measured to determine the effects of the different flow configurations. The results indicated that the double inlet/outlet configuration had the best flow distribution when using 75 cells. Moreover, increasing the stoichiometry resulted in a better flow distribution to the cells in a stack.
    Matched MeSH terms: Pressure
  4. Your mycotoxins in water paper
    Paterson RRM, Buddie A
    Environ Sci Pollut Res Int, 2019 05;26(13):13676.
    PMID: 30357675 DOI: 10.1007/s11356-018-3544-3
    Matched MeSH terms: Chromatography, High Pressure Liquid
  5. Fulltext Self-Calibration Algorithm for a Pressure Sensor with a Real-Time Approach Based on an Artificial Neural Network
    Almassri AMM, Wan Hasan WZ, Ahmad SA, Shafie S, Wada C, Horio K
    Sensors (Basel), 2018 Aug 05;18(8).
    PMID: 30081581 DOI: 10.3390/s18082561
    This paper presents a novel approach to predicting self-calibration in a pressure sensor using a proposed Levenberg Marquardt Back Propagation Artificial Neural Network (LMBP-ANN) model. The self-calibration algorithm should be able to fix major problems in the pressure sensor such as hysteresis, variation in gain and lack of linearity with high accuracy. The traditional calibration process for this kind of sensor is a time-consuming task because it is usually done through manual and repetitive identification. Furthermore, a traditional computational method is inadequate for solving the problem since it is extremely difficult to resolve the mathematical formula among multiple confounding pressure variables. Accordingly, this paper describes a new self-calibration methodology for nonlinear pressure sensors based on an LMBP-ANN model. The proposed method was achieved using a collected dataset from pressure sensors in real time. The load cell will be used as a reference for measuring the applied force. The proposed method was validated by comparing the output pressure of the trained network with the experimental target pressure (reference). This paper also shows that the proposed model exhibited a remarkable performance than traditional methods with a max mean square error of 0.17325 and an R-value over 0.99 for the total response of training, testing and validation. To verify the proposed model's capability to build a self-calibration algorithm, the model was tested using an untrained input data set. As a result, the proposed LMBP-ANN model for self-calibration purposes is able to successfully predict the desired pressure over time, even the uncertain behaviour of the pressure sensors due to its material creep. This means that the proposed model overcomes the problems of hysteresis, variation in gain and lack of linearity over time. In return, this can be used to enhance the durability of the grasping mechanism, leading to a more robust and secure grasp for paralyzed hands. Furthermore, the exposed analysis approach in this paper can be a useful methodology for the user to evaluate the performance of any measurement system in a real-time environment.
    Matched MeSH terms: Pressure
  6. Fulltext Morning surge in blood pressure and blood pressure variability in Asia: Evidence and statement from the HOPE Asia Network
    Sogunuru GP, Kario K, Shin J, Chen CH, Buranakitjaroen P, Chia YC, et al.
    J Clin Hypertens (Greenwich), 2019 02;21(2):324-334.
    PMID: 30525279 DOI: 10.1111/jch.13451
    Hypertension is a major risk factor for cardiovascular and cerebrovascular diseases. To effectively prevent end-organ damage, maintain vascular integrity and reduce morbidity and mortality, it is essential to decrease and adequately control blood pressure (BP) throughout each 24-hour period. Exaggerated early morning BP surge (EMBS) is one component of BP variability (BPV), and has been associated with an increased risk of stroke and cardiovascular events, independently of 24-hour average BP. BPV includes circadian, short-term and long-term components, and can best be documented using out-of-office techniques such as ambulatory and/or home BP monitoring. There is a large body of evidence linking both BPV and EMBS with increased rates of adverse cardio- and cerebrovascular events, and end-organ damage. Differences in hypertension and related cardiovascular disease rates have been reported between Western and Asian populations, including a higher rate of stroke, higher prevalence of metabolic syndrome, greater salt sensitivity and more common high morning and nocturnal BP readings in Asians. This highlights a need for BP management strategies that take into account ethnic differences. In general, long-acting antihypertensives that control BP throughout the 24-hour period are preferred; amlodipine and telmisartan have been shown to control EMBS more effectively than valsartan. Home and ambulatory BP monitoring should form an essential part of hypertension management, with individualized pharmacotherapy to achieve optimal 24-hour BP control particularly the EMBS and provide the best cardio- and cerebrovascular protection. Future research should facilitate better understanding of BPV, allowing optimization of strategies for the detection and treatment of hypertension to reduce adverse outcomes.
    Matched MeSH terms: Blood Pressure; Blood Pressure Determination/methods*; Blood Pressure Monitoring, Ambulatory
  7. Effects of inter-electrode gap and discharge voltage on EUV emission from stainless steel vacuum spark plasma
    Saboohi S, Yap S, Chan L, Wong C
    Sains Malaysiana, 2012;41:879-884.
    The emission of Extreme Ultra Violet (EUV) from plasma produced by vacuum spark discharge using stainless steel as anode material was investigated. The operating pressure for all the experiments carried out was maintained at below 10-4 mbar. The discharge voltage tested was from 8 kV to 20 kV. The inter-electrode distance suitable for high intensity and reproducible EUV emissions was found to be in the range of 2.6 mm to 4.6 mm. The output EUV energy scaled as ~ V02, where V0 is the discharge voltage.
    Matched MeSH terms: Pressure
  8. Kesan kepekatan asid performik terhadap pengepoksidaan minyak sawit olein
    Darfizzi Derawi, Jumat Salimon
    Sains Malaysiana, 2011;40:1123-1127.
    Kajian pengoptimuman tindak balas pengepoksidaan minyak sawit olein (POo) dengan menggunakan mangkin asid performik (HCOOOH) telah dijalankan. Kesan tindak balas terhadap nisbah kepekatan HCOOH : H2O2 dan masa tindak balas telah dikaji pada suhu 45oC. Kandungan oksigen oksirana (OOC) optimum sebanyak 3.61% diperoleh dengan menggunakan nisbah mol 1 : 5 : 2 pada 150 min dan sebanyak 96.5% penukaran dapat dicapai. Hasil tindak balas adalah sebanyak 91.3%. Puncak kromatografi cecair berprestasi tinggi (HPLC) bagi minyak sawit olein terepoksida (EPOo) telah berubah sepenuhnya berbanding puncak HPLC POo. Spektrum transformasi Fourier infra-merah (FTIR) telah menunjukkan kehadiran puncak ikatan gelang oksirana pada 844 cm-1.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  9. A review of blood pressure profile and hypertension studies in Malaysia
    Liew YM, Tan H, Khoo KL
    Family Physician, 1994;6:36-45.
    This paper reviews the literature on blood pressure profile and hypertension studies carried out in Peninsular Malaysia from 1952 to 1988. From these studies, the following key information is summarised: 1. Blood pressure profiles of Malaysians, irrespective of sex and the three major ethnic groups viz., Malay, Chinese and Indian followed a similar rising trend with age. 2. The mean systolic and diastolic pressures were 134 mmHg and 84 mmHg respectively across the major ethnic groups. 3. The prevalence of hypertension for Malaysians was 16.0%, 4.2% and 3.4% when 140/90 mmHg, 150/90 mmHg or a diastolic pressure of 100 mmHg or greater were taken as cut-off values respectively. Males generally showed a higher prevalence of hypertension than females. 4. Orang Asli living in the deep jungle had relatively low blood pressures (Mean: 109/70 mmHg) and their blood pressure did not rise with increasing age. 5. There was generally no difference in the prevalence of hypertension amongst the major ethnic groups. However, there was a tendency for the Malays to have a higher prevalence of hypertension than the Chinese or the Indians. 6. There was an increased prevalence of hypertension among subjects who smoked heavily or who did very little or no physical exercise. Differences in prevalence of hypertension among subjects living in changing environment and lifestyle, such as urban versus rural, alcohol versus non-alcohol consumers and low income versus moderate income groups were not evident in the studies reviewed. 7. Percent unawareness of hypertension in hypertension subjects was generally high i.e. 57 % - 69% except in one sample which recorded a moderately value (33%).
    Matched MeSH terms: Blood Pressure
  10. A finite element model to predict wellbore fracture pressure with acid damage
    Fanhui-Zeng, Jianchun-Guo, Yuxuan-Liu
    Sains Malaysiana, 2015;44:1377-1388.
    Hydraulic fracturing becomes more difficult when confronted with a formation of high fracturing pressure. In such formations, acidizing before the main fracturing treatment provide a method to reduce fracture pressure. The aim of this paper was to investigate the evolution of fracture pressure in a wellbore with acidizing. Five experiments were conducted to study the mechanisms of acid damage on reservoir minerals and cementing materials properties. Consequently, a mathematical model to predict fracture pressure with acidizing has been established and verified by field data. The analysis results showed that it is possible to reduce fracture pressure with decreased rock strength and fracture critical stress intensity factor by means of acid damage. Acid damage destroys the crystal structure of mineral particles, breaks the crystalline layers in cementing materials, increases rock porosity and reduces the rock strength. In addition, as the acid concentration, formation temperature and acid treatment time increased, it was useful to reduce fracture pressure in the wellbore. Using the proposed model, we were able to select the optimal acid damage construction parameters to reduce fracture pressure.
    Matched MeSH terms: Pressure
  11. Comparison of the performance of mr-deduster with other conventional cyclones
    Rashid M, Huda N, Norelyza H, Hasyimah N
    Sains Malaysiana, 2015;44:565-569.
    A new type of cyclone design configuration called MR-deDuster, which contains multi cyclone, has been developed.
    A theoretical study had been carried out to evaluate and predict the performance of a MR-deDuster. In this paper, a
    comparative study was done to investigate the performance of MR-deDuster with other conventional cyclones in terms
    of collection efficiency and pressure drop. The performance of MR-deDuster was measured by its collection efficiency
    based on the particle size distribution of activated carbon. It was found that MR-deDuster is able to collect as high as
    94% of PM10 which is high comparing with many other conventional cyclones. In addition, the pressure drop of the unit
    is relatively low compared to the other cyclones which highlight the ability of the unit to capture the fine particle at low
    pressure drop.
    Matched MeSH terms: Pressure
  12. Visco-hyperelastic model for soft rubber-like materials
    Mohd Afandi P. Mohammed
    Sains Malaysiana, 2014;43:451-457.
    This paper investigates the application of visco-hyperelastic model to soft rubberlike material, that is gluten. Gluten is a major protein in wheat flour dough (a mixture of flour and water) which exists as long network fibers and undergo large deformation under uniaxial tension and compression. The visco-hyperelastic model is represented by a combination of the viscoelastic Prony series and the hyperelastic extended tube model. Calibration of the visco-hyperelastic model to gluten tests result suggests that gluten can be modelled as a finite viscoelastic material.
    Matched MeSH terms: Pressure
  13. Laboratory study of acoustic velocity in different types of rocks at seismic frequency band
    Suping Peng, Wenfeng Du, Xiaoming Tang, Zeng Hu, Yunlan He
    Sains Malaysiana, 2017;46:2187-2193.
    In order to understand the characteristics of acoustic wave propagation in rocks within seismic frequency band (<100
    Hz), the velocities of longitudinal and transverse waves of four different types of rocks were tested using low-frequency
    stress-strain method by means of the physical testing system of rock at low frequency and the experimental data of acoustic
    velocities of four different types of rocks at this frequency band were obtained. The experimental results showed that the
    acoustic velocities of four different types of rocks increased with the increase of temperature and pressure within the
    temperature and pressure ranges set by the experiment. The acoustic velocity of fine sandstone at 50% water saturation
    was smaller than that of dry sample. The acoustic velocities of four different types of rocks were different and the velocities
    of longitudinal waves of gritstone, fine sandstone, argillaceous siltstone and mudstone increased in turn under similar
    conditions and were smaller than those at ultrasonic frequency. Few of existing studies focus on the acoustic velocity at
    seismic frequency band, thus, further understanding of the acoustic characteristics at this seismic frequency band still
    requires more experimental data.
    Matched MeSH terms: Pressure
  14. The influence of geometrical shapes of stenosis on the blood flow in stenosed artery
    Kamangar S, Nik-Ghazali N, Badarudin A, Ameer Ahamad N, Irfan Anjum Badruddin, Govindaraju K, et al.
    Sains Malaysiana, 2017;46:1923-1933.
    The present work was carried out to investigate the blood flow behavior and the severity of blockage caused in the
    arterial passage due to the different geometries such as elliptical, trapezium and triangular shapes of stenosis. The study
    was conducted with respect to various sizes of stenosis in terms of 70%, 80% and 90% area blockage of the arterial
    blood flow. The study was carried out numerically with the help of advance computational fluid dynamic software. It
    was found that the shape of the stenosis plays an important role in overall pressure drop across the blockage region
    of artery. The highest level of pressure drop was observed for trapezoidal shape of stenosis followed by elliptical and
    then by triangular shaped stenosis. The wall shear stress across the stenosis is great for trapezoidal shape followed by
    triangular and elliptical stenosis for same blockage area in the artery.
    Matched MeSH terms: Pressure
  15. Mechanical and thermal properties of graphene oxide filled epoxy nanocomposites
    Noorhafanita Norhakim, Sahrim Ahmad, Chin HC, Nay MH
    Sains Malaysiana, 2014;43:603-609.
    In this study, graphene oxide (Go) filled epoxy nanocomposites were prepared using hot pressed method. The GO was produced using modified Hummers' method. The produced GO at different compositions (0.1, 0.3 and 0.5 wt%) were mixed with epoxy before the addition of hardener using ultra-sonication. The produced epoxy nanocomposites were characterized in terms of mechanical and thermal properties. The mechanical properties of the nanocomposites were significantly enhanced by the addition of GO. About 50% of increment in the flexural strength of the composite sample filled with 03 wt% of GO as compared to the neat epoxy sample. However, only slight improvement in the impact strength of the composite were obtained by adding 0.1 wt% of GO.
    Matched MeSH terms: Pressure
  16. Controlling the blood flow in the stenosed porous artery with magnetic field
    Jamil D, Roslan R, Abdulhameed M, Hashim I
    Sains Malaysiana, 2018;47:2581-2587.
    The unsteady blood flow in the stenosed porous artery subjected to a magnetic field was studied analytically. Oscillating
    pressure gradient and periodic body acceleration were imposed on the flow field. The effects of the magnetic field and
    the permeability of the stenosed artery on the blood velocity were studied. The results showed that the magnetic field
    affected the flow field significantly which can be beneficial for some practical problems.
    Matched MeSH terms: Pressure
  17. Continuous distending pressure for respiratory distress syndrome in preterm infants
    Ho JJ, Subramaniam P, Henderson-Smart DJ, Davis PG
    Cochrane Database Syst Rev, 2000.
    PMID: 11034747
    BACKGROUND: Respiratory distress syndrome (RDS) is the single most important cause of morbidity and mortality in preterm infants (Greenough 1998, Bancalari 1992). Intermittent positive pressure ventilation (IPPV) with surfactant is the standard treatment for the condition. The major difficulty with IPPV is that it is invasive, resulting in airway and lung injury and contributing to the development of chronic lung disease.

    OBJECTIVES: In spontaneously breathing preterm infants with RDS, to determine if continuous distending pressure (CDP) reduces the need for IPPV and associated morbidity without adverse effects.

    SEARCH STRATEGY: The standard search strategy of the Neonatal Review group was used. This included searches of the Oxford Database of Perinatal Trials, Cochrane Controlled Trials Register, MEDLINE (1966-Jan. 2000), previous reviews including cross references, abstracts, conference and symposia proceedings, expert informants, journal hand searching mainly in the English language.

    SELECTION CRITERIA: All trials using random or quasi-random patient allocation of newborn infants with RDS were eligible. Interventions were continuous distending pressure including continuous positive airway pressure (CPAP) by mask, nasal prong, nasopharyngeal tube, or endotracheal tube, or continuous negative pressure (CNP) via a chamber enclosing the thorax and lower body, compared with standard care.

    DATA COLLECTION AND ANALYSIS: Standard methods of the Cochrane Collaboration and its Neonatal Review Group, including independent assessment of trial quality and extraction of data by each author, were used.

    MAIN RESULTS: CDP is associated with a lower rate of failed treatment (death or use of assisted ventilation), overall mortality, and mortality in infants with birthweights above 1500 g. The use of CDP is associated with an increased rate of pneumothorax.

    REVIEWER'S CONCLUSIONS: In preterm infants with RDS the application of CDP either as CPAP or CNP is associated with some benefits in terms of reduced respiratory failure and reduced mortality. CDP is associated with an increased rate of pneumothorax. The applicability of these results to current practice is difficult to assess, given the outdated methods to administer CDP, low use of antenatal corticosteroids, non-availability of surfactant and the intensive care setting of the 1970s when these trials were done. Where resources are limited, such as in developing countries, CPAP for RDS may have a clinical role. Further research is required to determine the best mode of administration and its role in modern intensive care settings

    Matched MeSH terms: Intermittent Positive-Pressure Ventilation/adverse effects; Positive-Pressure Respiration/methods*
  18. Fulltext Effect of surgical intraocular pressure lowering on retinal structures - nerve fibre layer, foveal avascular zone, peripapillary and macular vessel density: 1 year results
    Ch'ng TW, Gillmann K, Hoskens K, Rao HL, Mermoud A, Mansouri K
    Eye (Lond), 2020 03;34(3):562-571.
    PMID: 31409906 DOI: 10.1038/s41433-019-0560-6
    OBJECTIVES: To determine the effect of surgical intraocular pressure (IOP) lowering on peripapillary retinal nerve fibre layer thickness (RNFL), fovea avascular zone (FAZ), peripapillary and macular vessel density (VD) in glaucoma using with optical coherence tomography angiography (OCT-A).

    METHODS: This was a prospective observational study performed at the Glaucoma Research Centre, Montchoisi Clinic, Lausanne. In total 40 eyes with open-angle glaucoma were included. OCT-A scans were performed before glaucoma surgery, and at 1-month, 3-month, 6-month, and 12-month post-operatively. AngioVue AngioAnalytic (Optovue Inc, Fremont, CA) software was used to analyse the RNFL, FAZ, peripapillary and macular VD. Changes were analysed using analysis of variance (ANOVA) models.

    RESULTS: Mean IOP dropped from 19.4 (±7.0) mmHg pre-surgery and stabilized at 13.0 (±3.1) mmHg at 12 months (p 

    Matched MeSH terms: Intraocular Pressure
  19. Fulltext Wind shear data at two different terrain types
    Albani A, Ibrahim MZ, Yong KH
    Data Brief, 2019 Aug;25:104306.
    PMID: 31406911 DOI: 10.1016/j.dib.2019.104306
    The measurement of this data aims to evaluate the wind shear variability at three selected sites in Malaysia. The sites are Kudat in Sabah, Kijal in Terengganu and Langkawi in Kedah. Both sites in Kudat and Kijal is located in coastal areas with few buildings or trees, while the site in Langkawi is a coastal area with many buildings or trees. The variables were measured using the sensors that mounted on the wind mast with the maximum height from 55 m to 70 m from ground level. The variables measured were wind speed, wind direction, temperature, and pressure, while the wind shear data were directly generated using the power law equation. The averaged wind shear based on measured multiple height wind speed at selected sites is larger than the 1/7 law (0.143). Also, the value of wind shear was higher in order Langkawi > Kudat > Kijal. Ultimately, the wind shear data are essential and can be reused in the wind energy potential study, especially for data extrapolation to desired wind turbine hub height.
    Matched MeSH terms: Pressure
  20. Fulltext Influence of Secondary Reinforcement on Behaviour of Corbels with Various Types of High-Performance Fiber-Reinforced Cementitious Composites
    Md Zin N, Al-Fakih A, Nikbakht E, Teo W, Anwar Gad M
    Materials (Basel), 2019 Dec 11;12(24).
    PMID: 31835775 DOI: 10.3390/ma12244159
    An experimental study is conducted to determine the influence of secondary reinforcement on the behaviour of corbels fabricated with three different types of high-performance fiber-reinforced cementitious composites, including engineered cementitious concrete (ECC); high-performance steel fiber-reinforced composite (HPSFRC); and hybrid fiber-reinforced composite (HyFRC). Two shear span-to-depth ratios (a/d = 0.75 and 1.0) are explored. The mechanical properties of the composites in terms of tensile, compressive, and flexural strengths are investigated. Next, the structural behaviour of the high-performance cementitious composite corbels in terms of ultimate load capacity, ductility, and failure modes under the three-point bending test are investigated. The secondary reinforcement is proven to significantly affect stiffness and ultimately load capacity of all three high-performance composite corbels with an aspect ratio of 0.75. However, the secondary reinforcement was more impactful for the HPSFRC corbels, with 51% increase of ultimate strength. Moreover, in terms of damage, fewer cracks occurred in ECC corbels. HPSFRC corbels displayed the highest level of ductility and deformation capacity compared to the other specimens. The results were comparatively analyzed against the predicted results using truss and plastic truss models which provided relatively reliable shear strength.
    Matched MeSH terms: Pressure
Related Terms
Filters
Contact Us

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

External Links