Displaying publications 41 - 60 of 737 in total

Abstract:
Sort:
  1. Subramaniam S, Foo KY, Md Yusof EN, Jawad AH, Wilson LD, Sabar S
    Int J Biol Macromol, 2021 Dec 15;193(Pt B):1716-1726.
    PMID: 34742842 DOI: 10.1016/j.ijbiomac.2021.11.009
    Phosphorylated chitosan (P-CS) was successfully synthesized using a facile experimental setup of hydrothermal method that was applied to the adsorption of anionic Acid Red 88 (AR88) from aqueous media. The adsorption process obeyed the pseudo-second-order (PSO) kinetic model. In contrast, the adsorption isotherm conformed to the Langmuir model, with the maximum adsorption capacity (qm = 230 mg g-1) at 303 K. Both external and intraparticle diffusion strongly influenced the rate of adsorption. The insights from this study reveal that P-CS could be easily prepared and regenerated for reusability applications. The adsorption mechanism and intermolecular interaction between P-CS and AR 88 were investigated using Fourier transform infrared (FTIR) spectroscopy and calculations via Density Functional Theory (DFT). The key modes of adsorption for the P-CS/AR 88 system are driven by electrostatic attractions, H-bonding, and n-π interactions. The findings herein reveal that P-CS is a promising adsorbent for the removal of anionic dyes such as AR88 or similar pollutants from water.
    Matched MeSH terms: Hot Temperature*
  2. Khan I, Ali Shah N, Tassaddiq A, Mustapha N, Kechil SA
    PLoS One, 2018;13(1):e0188656.
    PMID: 29304161 DOI: 10.1371/journal.pone.0188656
    This paper studies the heat transfer analysis caused due to free convection in a vertically oscillating cylinder. Exact solutions are determined by applying the Laplace and finite Hankel transforms. Expressions for temperature distribution and velocity field corresponding to cosine and sine oscillations are obtained. The solutions that have been obtained for velocity are presented in the forms of transient and post-transient solutions. Moreover, these solutions satisfy both the governing differential equation and all imposed initial and boundary conditions. Numerical computations and graphical illustrations are used in order to study the effects of Prandtl and Grashof numbers on velocity and temperature for various times. The transient solutions for both cosine and sine oscillations are also computed in tables. It is found that, the transient solutions are of considerable interest up to the times t = 15 for cosine oscillations and t = 1.75 for sine oscillations. After these moments, the transient solutions can be neglected and, the fluid moves according with the post-transient solutions.
    Matched MeSH terms: Hot Temperature*
  3. Tiang KL, Ooi EH
    Med Eng Phys, 2016 Aug;38(8):776-84.
    PMID: 27340100 DOI: 10.1016/j.medengphy.2016.05.011
    The majority of the eye models developed in the late 90s and early 00s considers only heat conduction inside the eye. This assumption is not entirely correct, since the anterior and posterior chambers are filled aqueous humor (AH) that is constantly in motion due to thermally-induced buoyancy. In this paper, a three-dimensional model of the human eye is developed to investigate the effects AH hydrodynamics have on the human eye temperature under exposure to external heat sources. If the effects of AH flow are negligible, then future models can be developed without taking them into account, thus simplifying the modeling process. Two types of external thermal loads are considered; volumetric and surface irradiation. Results showed that heat convection due to AH flow contributes to nearly 95% of the total heat flow inside the anterior chamber. Moreover, the circulation inside the anterior chamber can cause an upward shift of the location of hotspot. This can have significant consequences to our understanding of heat-induced cataractogenesis.
    Matched MeSH terms: Hot Temperature*
  4. Yong KH, Teo YN, Azadbakht M, Phung H, Chu C
    Int J Environ Res Public Health, 2023 May 22;20(10).
    PMID: 37239636 DOI: 10.3390/ijerph20105910
    Global climate change has contributed to the intensity, frequency, and duration of heatwave events. The association between heatwaves and elderly mortality is highly researched in developed countries. In contrast, heatwave impact on hospital admissions has been insufficiently studied worldwide due to data availability and sensitivity. In our opinion, the relationship between heatwaves and hospital admissions is worthwhile to explore as it could have a profound impact on healthcare systems. Therefore, we aimed to investigate the associations between heatwaves and hospitalisations for the elderly by age group in Selangor, Malaysia, from 2010 to 2020. We further explored the impact of heatwaves on the risks of cause-specific hospital admissions across age groups within the elderly. This study applied generalized additive models (GAMs) with the Poisson family and distributed lag models (DLMs) to estimate the effect of heatwaves on hospitalisations. According to the findings, there was no significant increase in hospitalisations for those aged 60 and older during heatwaves; however, a rise in mean apparent temperature (ATmean) by 1 °C significantly increased the risk of hospital admission by 12.9%. Heatwaves had no immediate effects on hospital admissions among elderly patients, but significant delay effects were identified for ATmean with a lag of 0-3 days. The hospital admission rates of the elderly groups started declining after a 5-day average following the heatwave event. Females were found to be relatively more vulnerable than males during heatwave periods. Consequently, these results can provide a reference to improve public health strategies to target elderly people who are at the greatest risk of hospitalisations due to heatwaves. Development of early heatwave and health warning systems for the elderly would assist with preventing and reducing health risks while also minimising the burden on the whole hospital system in Selangor, Malaysia.
    Matched MeSH terms: Hot Temperature*
  5. Koosha N, Mosavi V, Kheirollah J, Najafi N, Abdi N, Alizadeh A, et al.
    J Therm Biol, 2023 Oct;117:103718.
    PMID: 37812951 DOI: 10.1016/j.jtherbio.2023.103718
    The study of blood flow in obstructed arteries is a significant focus in computational fluid dynamics, particularly in the field of biomedicine. The primary objective of this research is to investigate the impact of pulsating blood velocity on heat transfer within biological systems, with a specific focus on blood flow in obstructed arteries. To achieve this goal, a comprehensive 3D model representing a straight, constricted blood vessel has been developed. This model incorporates periodic, unsteady, Newtonian blood flow along with the presence of gold and silver nanoparticles. Leveraging the Finite Element Method (FEM), the Navier-Stokes and energy equations have been rigorously solved. Through the investigation, it is aim to shed light on how alterations in the pulsation rate and the volume fraction of nanoparticles influence both temperature distribution and velocity profiles within the system. The present study findings unequivocally highlight that the behavior of pulsatile nanofluid flow significantly impacts the velocity field and heat transfer performance. However, it is imperative to note that the extent of this influence varies depending on the specific volume fractions involved. Specifically, higher volume fractions of nanofluids correlate with elevated velocities at the center of the vessel and decreased velocities near the vessel walls. This pattern also extends to the temperature distribution and heat flux within the vessel, further underscoring the paramount importance of pulsatile flow dynamics in biomedicine and computational fluid dynamics research. Besides, results revealed that the presence of occlusion significantly affects the heat transfer and fluid flow.
    Matched MeSH terms: Hot Temperature*
  6. Tie HO, Che Man H, Koyama M, Syukri F, Md Yusoff F, Toda T, et al.
    Waste Manag, 2023 Jul 01;166:194-202.
    PMID: 37178588 DOI: 10.1016/j.wasman.2023.04.046
    A modified outdoor large-scale nutrient recycling system was developed to compost organic sludge and aimed to recover clean nitrogen for the cultivation of high-value-added microalgae. This study investigated the effect of calcium hydroxide addition on enhancing NH3 recovery in a pilot-scale reactor self-heated by metabolic heat of microorganisms during thermophilic composting of dewatered cow dung. 350 kg-ww of compost was prepared at the ratio of 5: 14: 1 (dewatered cowdung: rice husk: compost-seed) in a 4 m3 cylindrical rotary drum composting reactor for 14 days of aerated composting. High compost temperature up to 67 °C was observed from day 1 of composting, proving that thermophilic composting was achieved through the self-heating process. The temperature of compost increases as microbial activity increases and temperature decreases as organic matter decreases. The high CO2 evolution rate on day 0-2 (0.02-0.08 mol/min) indicated that microorganisms are most active in degrading organic matter. The increasing conversion of carbon demonstrated that organic carbon was degraded by microbial activity and emitted as CO2. The nitrogen mass balance revealed that adding calcium hydroxide to the compost and increasing the aeration rate on day 3 volatilized 9.83 % of the remaining ammonium ions in the compost, thereby improving the ammonia recovery. Moreover, Geobacillus was found to be the most dominant bacteria under elevated temperature that functions in the hydrolysis of non-dissolved nitrogen for better NH3 recovery. The presented results show that by thermophilic composting 1 ton-ds of dewatered cowdung for NH3 recovery, up to 11.54 kg-ds of microalgae can be produced.
    Matched MeSH terms: Hot Temperature*
  7. May LW, John J, Seong LG, Abidin ZZ, Ibrahim N, Danaee M, et al.
    J Indian Prosthodont Soc, 2021 5 4;21(2):198-203.
    PMID: 33938871 DOI: 10.4103/jips.jips_41_21
    Aim: To investigate the effect of different cooling methods on denture base adaptation of rapid heat-cured acrylic resin using 3D superimposition technique.

    Setting and Design: In vitro - Comparative study.

    Materials and Methods: Denture base adaptation of two different rapid heat-cured polymethyl methacrylate acrylic resins using five different cooling methods were compared. Forty maxillary edentulous stone cast were prepared to produce the denture bases with standardized thickness. The specimens were divided into five groups (n = 8) according to type of materials and cooling methods. The master stone cast and all forty denture bases were scanned with 3Shape E1 laboratory scanner. The scanned images of each of the denture bases were superimposed over the scanned image of the master cast using Materialize 3-matic software. Three dimensional differences between the two surfaces were calculated and color surface maps were generated for visual qualitative assessment.

    Statistical Analysis Used: Generalized Linear Model Test, Bonferroni Post Hoc Analysis.

    Results: All bench-cooled specimens showed wide green-colored area in the overall palatal surface, while the rapid cooled specimens presented with increased red color areas especially at the palate and post dam area. Generalized Linear Model test followed by Bonferroni post hoc analysis showed significant difference in the root mean square values among the specimen groups.

    Conclusion: Samples that were bench cooled, demonstrated better overall accuracy compared to the rapid cooling groups. Regardless of need for shorter denture processing time, bench cooling of rapid heat-cured PMMA is essential for acceptable denture base adaptation.

    Matched MeSH terms: Hot Temperature*
  8. Krishnakumar P, Sundaramurthy S, Baredar P, Suresh A, Khan MA, Sharma G, et al.
    Environ Sci Pollut Res Int, 2023 Dec;30(60):125104-125116.
    PMID: 37099105 DOI: 10.1007/s11356-023-26991-6
    There are several environmental and human health impacts if human hair waste is not adequately disposed of. In this study, pyrolysis of discarded human hair was carried out. This research focused on the pyrolysis of discarded human hair under controlled environmental conditions. The effects of the mass of discarded human hair and temperature on bio-oil yield were studied. The proximate and ultimate analyses and calorific values of disposed of human hair, bio-oil, and biochar were determined. Further, chemical compounds of bio-oil were analyzed using a gas chromatograph and a mass spectrometer. Finally, the kinetic modeling and behavior of the pyrolysis process were characterized through FT-IR spectroscopy and thermal analysis. Based on the optimized mass of disposed of human hair, 250 g had a better bio-oil yield of 97% in the temperature range of 210-300 °C. The different parameters of bio-oil were: pH (2.87), specific gravity (1.17), moisture content (19%), heating value (19.34 MJ/kg), and viscosity (50 CP). C (56.4%), H (6.1%), N (0.16%), S (0.01%), O (38.4%), and Ash (0.1%) were discovered to be the elemental chemical composition of bio-oil (on a dry basis). During breakdown, the release of different compounds like hydrocarbons, aldehydes, ketones, acids, and alcohols takes place. According to the GC-MS results, several amino acids were discovered in the bio-oil, 12 abundant in the discarded human hair. The FTIR and thermal analysis found different concluding temperatures and wave numbers for functional groups. Two main stages are partially separated at about 305 °C, with maximum degradation rates at about 293 oC and 400-4140 °C, respectively. The mass loss was 30% at 293 0C and 82% at temperatures above 293 0C. When the temperature reached 4100C, the entire bio-oil from discarded human hair was distilled or thermally decomposed.
    Matched MeSH terms: Hot Temperature*
  9. Yasin MH, Ishak A, Pop I
    Sci Rep, 2015;5:17848.
    PMID: 26647651 DOI: 10.1038/srep17848
    The steady two-dimensional stagnation-point flow and heat transfer past a permeable stretching/shrinking sheet with effects of viscous dissipation, Joule heating and partial velocity slip in the presence of a magnetic field is investigated. The partial differential equations are reduced to nonlinear ordinary differential equations by using a similarity transformation, before being solved numerically by shooting technique. Results indicate that the skin friction coefficient and the local Nusselt number increase as magnetic parameter increases. It is found that for the stretching sheet the solution is unique while for the shrinking sheet there exist nonunique solutions (dual solutions) in certain range of parameters. The stability analysis shows that the upper branch solution is stable while the lower branch solution is unstable.
    Matched MeSH terms: Hot Temperature
  10. Hussanan A, Zuki Salleh M, Tahar RM, Khan I
    PLoS One, 2014;9(10):e108763.
    PMID: 25302782 DOI: 10.1371/journal.pone.0108763
    In this paper, the heat transfer effect on the unsteady boundary layer flow of a Casson fluid past an infinite oscillating vertical plate with Newtonian heating is investigated. The governing equations are transformed to a systems of linear partial differential equations using appropriate non-dimensional variables. The resulting equations are solved analytically by using the Laplace transform method and the expressions for velocity and temperature are obtained. They satisfy all imposed initial and boundary conditions and reduce to some well-known solutions for Newtonian fluids. Numerical results for velocity, temperature, skin friction and Nusselt number are shown in various graphs and discussed for embedded flow parameters. It is found that velocity decreases as Casson parameters increases and thermal boundary layer thickness increases with increasing Newtonian heating parameter.
    Matched MeSH terms: Hot Temperature
  11. Hamid RA, Nazar R, Pop I
    Sci Rep, 2015;5:14640.
    PMID: 26440761 DOI: 10.1038/srep14640
    The paper deals with a stagnation-point boundary layer flow towards a permeable stretching/shrinking sheet in a nanofluid where the flow and the sheet are not aligned. We used the Buongiorno model that is based on the Brownian diffusion and thermophoresis to describe the nanofluid in this problem. The main purpose of the present paper is to examine whether the non-alignment function has the effect on the problem considered when the fluid suction and injection are imposed. It is interesting to note that the non-alignment function can ruin the symmetry of the flows and prominent in the shrinking sheet. The fluid suction will reduce the impact of the non-alignment function of the stagnation flow and the stretching/shrinking sheet but at the same time increasing the velocity profiles and the shear stress at the surface. Furthermore, the effects of the pertinent parameters such as the Brownian motion, thermophoresis, Lewis number and the suction/injection on the flow and heat transfer characteristics are also taken into consideration. The numerical results are shown in the tables and the figures. It is worth mentioning that dual solutions are found to exist for the shrinking sheet.
    Matched MeSH terms: Hot Temperature
  12. Ng KH
    Med Lab Sci, 1991 Jul;48(3):189-92.
    PMID: 1787775
    Uniformity of electric field intensity of microwaves within the microwave oven cavity is necessary to ensure even load-heating, and is particularly important in pathology procedures where small volume irradiation is carried out. A simple and rapid method for mapping electric field distribution, using reversible thermographic paint, is described. Spatial heating patterns for various positions, and the effects of introducing dummy loads to modify heating distributions, have been obtained for a dedicated microwave processor, and comparison made with a domestic microwave oven.
    Matched MeSH terms: Hot Temperature
  13. Kohilavani Naganthran, Roslinda Nazar, Ioan Pop
    Sains Malaysiana, 2018;47:1069-1076.
    This study offers the numerical solutions for the problem of mixed convection stagnation-point flow along a permeable
    vertical flat plate in an Oldroyd-B fluid. The present investigation considers the effects of thermal radiation and heat
    generation/absorption in the fluid flow. The similarity transformation simplifies the complex model and the bvp4c function
    generates the numerical solutions according to the variations in the governing parameters. A higher degree of shrinking
    hastens flow separations. The dual solutions are visible in the range of buoyancy opposing flow. The results from this study
    may be useful for the scientist to understand the behaviour of the dilute polymer solutions in the industrial applications,
    for example, the drag reduction in pipe flows.
    Matched MeSH terms: Hot Temperature
  14. Chan WP, Veksha A, Lei J, Oh WD, Dou X, Giannis A, et al.
    J Environ Manage, 2019 Mar 15;234:65-74.
    PMID: 30616190 DOI: 10.1016/j.jenvman.2018.12.107
    A novel, cost-effective and real-time process monitoring and control system was developed to maintain stable operation of waste-to-energy gasification process. It comprised a feedback loop control that utilized the differential temperatures of the oxidation and reduction zones in the gasifier to determine the regional heat-flow (endothermic or exothermic), to assess the availability of oxidizing agent (for instance, air or O2) at the char bed and to calculate the fuel feeding rate. Based on the correlations developed, the air-to-fuel ratio or the equivalence air ratio (ER) for air gasification could be instantaneously adjusted to maintain stable operation of the gasifier. This study demonstrated a simplification of complex reaction dynamics in the gasification process to differential temperature profiling of the gasifier. The monitoring and control system was tested for more than 70 h of continuous operation in a downdraft fixed-bed gasifier with refuse-derived fuel (RDF) prepared from municipal solid wastes (MSW). With the system, fuel feeding rate could be adjusted accurately to stabilize the operating temperature and ER in the gasifier and generate syngas with consistent properties. Significant reductions in the fluctuations of temperature profiles at oxidation and reduction zones (from higher than 100 °C to lower than 50 °C), differential temperatures (from ±200 to ±50 °C) in gasifier and the flow rate (from 16 ± 6.5 to 12 ± 1.8 L/min), composition of main gas components, LHV (from 6.2 ± 3.1 to 5.7 ± 1.6 MJ/Nm3) and tar content (from 8.0 ± 9.7 to 7.5 ± 4.2 g/Nm3) of syngas were demonstrated. The developed gasifier monitoring and control system is adaptable to various types (updraft, downdraft, and fluidized-bed) and scales (lab, pilot, large scale) of gasifiers with different types of fuel.
    Matched MeSH terms: Hot Temperature
  15. Zainazlan Md Zain1, Mohd Nasir Taib, Shahrizam M. S. Baki, Azni Zain Ahmed
    MyJurnal
    This paper examines the temperature profile of a building material and also a
    built space. The study directly examines the influence of solar radiation on
    building material and the heat it generated and diffuses into the built space.
    Two experiments are presented. The first look at a simple technique for
    evaluating heat performance of a building material, and the second evaluates
    the performance of a cross-ventilated built space with respect to solar radiation.
    Matched MeSH terms: Hot Temperature
  16. Zainuddin N, Saleh H, Hashim I, Roslan R
    Sains Malaysiana, 2016;45:315-321.
    Effects of radiation on free convection about a heated horizontal circular cylinder in the presence of heat generation is investigated numerically. The cylinder is fixed and immersed in a stationary fluid, in which the temperature is uniformly heated about the temperature of the surrounding fluid. The governing equations are transformed into dimensionless non-linear partial differential equations and solved by employing a finite difference method. An implicit finite difference scheme of Crank Nicolson method is used to analyze the results. This study determined the effects of radiation parameter, heat generation parameter, and the Prandtl number, on the temperature and velocity profiles. The results of the local heat transfer and skin-friction coefficient in the presence of radiation for some selected values of and are shown graphically.
    Matched MeSH terms: Hot Temperature
  17. Muhammad Khairul Anuar Mohamed, Nor Aida Zuraimi Md Noar, Mohd Zuki Salleh, Anuar Ishak
    Sains Malaysiana, 2016;45:189-296.
    In this paper, the problem of free convection boundary layer flow on a horizontal circular cylinder in a nanofluid with viscous dissipation and constant wall temperature is investigated. The transformed boundary layer equations are solved numerically using finite difference scheme namely the Keller-box method. Numerical solutions were obtained for the reduced skin friction coefficient, Nusselt number and Sherwood number as well as the velocity and temperature profiles.The features of the flow and heat transfer characteristics for various values of the Brownian motion parameter, thermophoresis parameter, Lewis number and Eckert number were analyzed and discussed.
    Matched MeSH terms: Hot Temperature
  18. Yahaya Shagaiya Daniel, Zainal Abdul Aziz, Zuhaila Ismail, Faisal Salah
    MATEMATIKA, 2018;34(2):393-417.
    MyJurnal
    Analyzed the effects of thermal radiation, chemical reaction, heat gener-
    ation/absorption, magnetic and electric fields on unsteady flow and heat transfer of
    nanofluid. The transport equations used passively controlled. A similarity solution is
    employed to transformed the governing equations from partial differential equations to
    a set of ordinary differential equations, and then solve using Keller box method. It was
    found that the temperature is a decreasing function with the thermal stratification due to
    the fact the density of the fluid in the lower vicinity is much higher compared to the upper
    region, whereas the thermal radiation, viscous dissipation and heat generation enhanced
    the nanofluid temperature and thermal layer thickness.
    Matched MeSH terms: Hot Temperature
  19. Chen WH, Cheng CL, Lee KT, Lam SS, Ong HC, Ok YS, et al.
    Chemosphere, 2021 May;271:129510.
    PMID: 33434827 DOI: 10.1016/j.chemosphere.2020.129510
    Zeolite socony mobil-5 (ZSM-5) is a common catalyst used for biomass pyrolysis. Nevertheless, the quantitative information on the catalytic behavior of ZSM-5 on biomass pyrolysis is absent so far. This study focuses on the catalytic pyrolysis phenomena and mechanisms of biomass wastes using ZSM-5 via thermogravimetric analyzer and pyrolysis-gas chromatography/mass spectrometry, with particular emphasis on catalytic level identification and aromatic hydrocarbons (AHs) formation. Two biomass wastes of sawdust and sorghum distillery residue (SDR) are investigated, while four biomass-to-catalyst ratios are considered. The analysis suggests that biomass waste pyrolysis processes can be divided into three zones, proceeding from a heat-transfer dominant zone (zone 1) to catalysis dominant zones (zones 2 and 3). The indicators of the intensity of difference (IOD), catalytic effective area, catalytic index (CI), and aromatic enhancement index are conducted to measure the catalytic effect of ZSM-5 on biomass waste pyrolysis and AHs formation. The maximum IOD occurs in zone 2, showing the highest intensity of the catalytic effect. The CI values of the two biomass wastes increase with increasing the biomass-to-catalyst ratio. However, there exists a threshold for sawdust pyrolysis, indicating a limit for the catalytic effect on sawdust. The higher the catalyst addition, the higher the AHs proportion in the vapor stream. When the biomass-to-catalyst ratio is 1/10, AHs formation is intensified significantly, especially for sawdust. Overall, the indexes conducted in the present study can provide useful measures to identify the catalytic pyrolysis dynamics and levels.
    Matched MeSH terms: Hot Temperature
  20. Harikrishnan H, Ismail A, Banga Singh KK
    Gut Pathog, 2013;5(1):38.
    PMID: 24330657 DOI: 10.1186/1757-4749-5-38
    Bacteria exist widely in a diversity of natural environments. In order to survive adverse conditions such as nutrient depletion, biochemical and biological disturbances, and high temperature, bacteria have developed a wide variety of coping mechanisms. Temperature is one of the most important factors that can enhance the expression of microbial proteins. This study was conducted to investigate how outer membrane proteins (OMPs) of the bacterium Shigella flexneri respond to stress, especially during fever when the host's body temperature is elevated.
    Matched MeSH terms: Hot Temperature
Filters
Contact Us

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

External Links