Displaying publications 1 - 20 of 2926 in total

  1. Mak NL, Ooi EH, Lau EV, Ooi ET, Pamidi N, Foo JJ, et al.
    Comput Methods Programs Biomed, 2022 Dec;227:107195.
    PMID: 36323179 DOI: 10.1016/j.cmpb.2022.107195
    BACKGROUND AND OBJECTIVES: Thermochemical ablation (TCA) is a thermal ablation technique involving the injection of acid and base, either sequentially or simultaneously, into the target tissue. TCA remains at the conceptual stage with existing studies unable to provide recommendations on the optimum injection rate, and reagent concentration and volume. Limitations in current experimental methodology have prevented proper elucidation of the thermochemical processes inside the tissue during TCA. Nevertheless, the computational TCA framework developed recently by Mak et al. [Mak et al., Computers in Biology and Medicine, 2022, 145:105494] has opened new avenues in the development of TCA. Specifically, a recommended safe dosage is imperative in driving TCA research beyond the conceptual stage.

    METHODS: The aforesaid computational TCA framework for sequential injection was applied and adapted to simulate TCA with simultaneous injection of acid and base at equimolar and equivolume. The developed framework, which describes the flow of acid and base, their neutralisation, the rise in tissue temperature and the formation of thermal damage, was solved numerically using the finite element method. The framework will be used to investigate the effects of injection rate, reagent concentration, volume and type (weak/strong acid-base combination) on temperature rise and thermal coagulation formation.

    RESULTS: A higher injection rate resulted in higher temperature rise and larger thermal coagulation. Reagent concentration of 7500 mol/m3 was found to be optimum in producing considerable thermal coagulation without the risk of tissue overheating. Thermal coagulation volume was found to be consistently larger than the total volume of acid and base injected into the tissue, which is beneficial as it reduces the risk of chemical burn injury. Three multivariate second-order polynomials that express the targeted coagulation volume as functions of injection rate and reagent volume, for the weak-weak, weak-strong and strong-strong acid-base combinations were also derived based on the simulated data.

    CONCLUSIONS: A guideline for a safe and effective implementation of TCA with simultaneous injection of acid and base was recommended based on the numerical results of the computational model developed. The guideline correlates the coagulation volume with the reagent volume and injection rate, and may be used by clinicians in determining the safe dosage of reagents and optimum injection rate to achieve a desired thermal coagulation volume during TCA.

    Matched MeSH terms: Hot Temperature; Temperature
  2. Matinja AI, Kamarudin NHA, Leow ATC, Oslan SN, Ali MSM
    Int J Mol Sci, 2022 Dec 06;23(23).
    PMID: 36499718 DOI: 10.3390/ijms232315394
    Cold environments characterised by diverse temperatures close to or below the water freezing point dominate about 80% of the Earth's biosphere. One of the survival strategies adopted by microorganisms living in cold environments is their expression of cold-active enzymes that enable them to perform an efficient metabolic flux at low temperatures necessary to thrive and reproduce under those constraints. Cold-active enzymes are ideal biocatalysts that can reduce the need for heating procedures and improve industrial processes' quality, sustainability, and cost-effectiveness. Despite their wide applications, their industrial usage is still limited, and the major contributing factor is the lack of complete understanding of their structure and cold adaptation mechanisms. The current review looked at the recombinant overexpression, purification, and recent mechanism of cold adaptation, various approaches for purification, and three-dimensional (3D) crystal structure elucidation of cold-active lipases and esterase.
    Matched MeSH terms: Cold Temperature
  3. Chaudhry MT, Ling TC, Hussain SA, Manzoor A
    ScientificWorldJournal, 2014;2014:684501.
    PMID: 24987743 DOI: 10.1155/2014/684501
    A rise in inlet air temperature may lower the rate of heat dissipation from air cooled computing servers. This introduces a thermal stress to these servers. As a result, the poorly cooled active servers will start conducting heat to the neighboring servers and giving rise to hotspot regions of thermal stress, inside the data center. As a result, the physical hardware of these servers may fail, thus causing performance loss, monetary loss, and higher energy consumption for cooling mechanism. In order to minimize these situations, this paper performs the profiling of inlet temperature sensitivity (ITS) and defines the optimum location for each server to minimize the chances of creating a thermal hotspot and thermal stress. Based upon novel ITS analysis, a thermal state monitoring and server relocation algorithm for data centers is being proposed. The contribution of this paper is bringing the peak outlet temperatures of the relocated servers closer to average outlet temperature by over 5 times, lowering the average peak outlet temperature by 3.5% and minimizing the thermal stress.
    Matched MeSH terms: Temperature*
  4. Gitan AA, Zulkifli R, Abdullah S, Sopian K
    ScientificWorldJournal, 2014;2014:767614.
    PMID: 24672370 DOI: 10.1155/2014/767614
    Pulsating twin jets mechanism (PTJM) was developed in the present work to study the effect of pulsating twin jets mixing region on the enhancement of heat transfer. Controllable characteristics twin pulsed jets were the main objective of our design. The variable nozzle-nozzle distance was considered to study the effect of two jets interaction at the mixing region. Also, the phase change between the frequencies of twin jets was taken into account to develop PTJM. All of these factors in addition to the ability of producing high velocity pulsed jet led to more appropriate design for a comprehensive study of multijet impingement heat transfer problems. The performance of PTJM was verified by measuring the pulse profile at frequency of 20 Hz, where equal velocity peak of around 64 m/s for both jets was obtained. Moreover, the jet velocity profile at different pulsation frequencies was tested to verify system performance, so the results revealed reasonable velocity profile configuration. Furthermore, the effect of pulsation frequency on surface temperature of flat hot plate in the midpoint between twin jets was studied experimentally. Noticeable enhancement in heat transfer was obtained with the increasing of pulsation frequency.
    Matched MeSH terms: Hot Temperature*
  5. Ismail MA, Tamchek N, Hassan MR, Dambul KD, Selvaraj J, Rahim NA, et al.
    Sensors (Basel), 2011;11(9):8665-73.
    PMID: 22164098 DOI: 10.3390/s110908665
    This paper reports the design, characterization and implementation of a fiber Bragg grating (FBG)-based temperature sensor for an insulted-gate Bipolar transistor (IGBT) in a solar panel inverter. The FBG is bonded to the higher coefficient of thermal expansion (CTE) side of a bimetallic strip to increase its sensitivity. Characterization results show a linear relationship between increasing temperature and the wavelength shift. It is found that the sensitivity of the sensor can be categorized into three characterization temperature regions between 26 °C and 90 °C. The region from 41 °C to 90 °C shows the highest sensitivity, with a value of 14 pm/°C. A new empirical model that considers both temperature and strain effects has been developed for the sensor. Finally, the FBG-bimetal temperature sensor is placed in a solar panel inverter and results confirm that it can be used for real-time monitoring of the IGBT temperature.
    Matched MeSH terms: Temperature*
  6. Muhammad Aniq Qayyum Mohamad Sukry, Norazlina Subani, Muhammad Arif Hannan, Faizzuddin Jamaluddin, Ahmad Danial Hidayatullah Badrolhisam
    Partial differential equations involve results of unknown functions when there are multiple independent variables. There is a need for analytical solutions to ensure partial differential equations could be solved accurately. Thus, these partial differential equations could be solved using the right initial and boundaries conditions. In this light, boundary conditions depend on the general solution; the partial differential equations should present particular solutions when paired with varied boundary conditions. This study analysed the use of variable separation to provide an analytical solution of the homogeneous, one-dimensional heat equation. This study is applied to varied boundary conditions to examine the flow attributes of the heat equation. The solution is verified through different boundary conditions: Dirichlet, Neumann, and mixed-insulated boundary conditions. the initial value was kept constant despite the varied boundary conditions. There are two significant findings in this study. First, the temperature profile changes are influenced by the boundary conditions, and that the boundary conditions are dependent on the heat equation’s flow attributes.

    Matched MeSH terms: Hot Temperature; Temperature
    Med J Malaya, 1956 Jun;10(4):326-31.
    PMID: 13399535
    Matched MeSH terms: Temperature*
  8. Fazlian Aman, Anuar Ishak, Pop J
    Sains Malaysiana, 2011;40:1369-1374.
    The heat transfer behaviour of a viscous fluid over a stretching/shrinking sheet driven by a uniform shear in the far field with a convective surface boundary condition is studied. The boundary layer equations governing the flow are reduced to ordinary differential equations using a similarity transformation. Using a numerical technique, these equations are then solved to obtain the temperature distributions and the heat transfer rate at the surface for various values of Prandtl number, stretching/shrinking parameter and convective parameter. Dual solutions are found to exist for the shrinking case, whereas for the stretching case, the solution is unique.
    Matched MeSH terms: Hot Temperature; Temperature
  9. Arumugam S, Yew HZ, Baharin SA, Qamaruz Zaman J, Muchtar A, Kanagasingam S
    Aust Endod J, 2021 Dec;47(3):520-530.
    PMID: 33956372 DOI: 10.1111/aej.12516
    This study aimed to evaluate and compare the frequency of microcracks and its severity at different root canal dentin locations, after preparation with thermomechanically heat-treated engine-driven nickel-titanium instruments. Forty mandibular premolars were assigned to four experimental groups (n = 10): ProTaper Next, ProTaper Gold, WaveOne Gold and Reciproc Blue. After pre-instrumentation micro-computed tomography scans, the root canals were prepared to size 25. Following post-instrumentation scans, pre- and post-instrumentation scanned images were analysed for the presence and extent of dentinal defects. A total of 56 500 cross-sectional images were obtained, showing that less than 2.3% with pre-existing dentinal microcracks. No new microcracks were identified during the post-instrumentation analyses. No significant association was found between the types of dentinal defects, file motions and sequences. Thermomechanically heat-treated rotary files did not induce the formation of new microcracks. There was also no association between the kinematic motions and sequences of the rotary instruments to the types of dentinal defects.
    Matched MeSH terms: Hot Temperature*
  10. Jaafar NR, Mahadi NM, Mackeen MM, Illias RM, Murad AMA, Abu Bakar FD
    J Biotechnol, 2021 Mar 10;329:118-127.
    PMID: 33539893 DOI: 10.1016/j.jbiotec.2021.01.019
    Dehydroquinase or 3-dehydroquinate dehydratase (DHQD) reversibly cleaves 3-dehydroquinate to form 3-dehydroshikimate. Here, we describe the functional and structural features of a cold active type II 3-dehydroquinate dehydratase from the psychrophilic yeast, Glaciozyma antarctica PI12 (GaDHQD). Functional studies showed that the enzyme was active at low temperatures (10-30 °C), but displayed maximal activity at 40 °C. Yet the enzyme was stable over a wide range of temperatures (10-70 °C) and between pH 6.0-10.0 with an optimum pH of 8.0. Interestingly, the enzyme was highly thermo-tolerant, denaturing only at approximately 84 °C. Three-dimensional structure analyses showed that the G. antarctica dehydroquinase (GaDHQD) possesses psychrophilic features in comparison with its mesophilic and thermophilic counterparts such as higher numbers of non-polar residues on the surface, lower numbers of arginine and higher numbers of glycine-residues with lower numbers of hydrophobic interactions. On the other hand, GaDHQD shares some traits (i.e. total number of hydrogen bonds, number of proline residues and overall folding) with its mesophilic and thermophilic counterparts. Combined, these features contribute synergistically towards the enzyme's ability to function at both low and high temperatures.
    Matched MeSH terms: Cold Temperature*; Hot Temperature*
  11. Dee, S., Singh, B., Remeli, M.F., Tan, L., Oberoi, A.
    This paper looks at electrical power generation from solar concentrator using thermoelectric generator. An experiment was conducted on a concentrator thermoelectric generator (CTEG) utilising solar thermal energy. The CTEG used a parabolic dish as concentrator with thermoelectric device installed at the focal point to convert thermal energy to generate electricity. The investigation covered the cooling effect of the cold side of the thermoelectric generator using natural and forced convection cooling for optimum output. Forced convection cooling with a fan provided 69% more power output from the CTEG system as the temperature difference across the TEG was greater than the system cooled by natural convection. The outcome of this project showed maximum power output was obtained for the CTEG system cooled by forced convection cooling.
    Matched MeSH terms: Body Temperature; Cold Temperature; Hot Temperature; Temperature
  12. 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: Body Temperature Regulation; Hot Temperature; Temperature
  13. Yahaya Shagaiya Daniel, Zainal Abdul Aziz, Zuhaila Ismail, Faisal Salah
    MATEMATIKA, 2018;34(2):393-417.
    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: Body Temperature Regulation; Hot Temperature; Temperature
  14. Rosli NS, Ibrahim R, Ismail I, Omar M
    PLoS One, 2022;17(11):e0276142.
    PMID: 36445921 DOI: 10.1371/journal.pone.0276142
    Achieving reliable power efficiency from a high voltage induction motor (HVIM) is a great challenge, as the rigorous control strategy is susceptible to unexpected failure. External cooling is commonly used in an HVIM cooling system, and it is a vital part of the motor that is responsible for keeping the motor at the proper operating temperature. A malfunctioning cooling system component can cause motor overheating, which can destroy the motor and cause the entire plant to shut down. As a result, creating a dynamic model of the motor cooling system for quality performance, failure diagnosis, and prediction is critical. However, the external motor cooling system design in HVIM is limited and separately done in the past. With this issue in mind, this paper proposes a combined modeling approach to the HVIM cooling system which consists of integrating the electrical, thermal, and cooler model using the mathematical model for thermal performance improvement. Firstly, the development of an electrical model using an established mathematical model. Subsequently, the development of a thermal model using combined mathematical and linear regression models to produce motor temperature. Then, a modified cooler model is developed to provide cold air temperature for cooling monitoring. All validated models are integrated into a single model called the HVIM cooling system as the actual setup of the HVIM. Ultimately, the core of this modeling approach is integrating all models to accurately represent the actual signals of the motor cooler temperature. Then, the actual signals are used to validate the whole structure of the model using Mean Absolute Percentage Error (MAPE) and Root Mean Square Error (RMSE) analysis. The results demonstrate the high accuracy of the HVIM cooling system representation with less than 1% error tolerance based on the industrial plant experts. Thus, it will be helpful for future utilization in quality maintenance, fault identification and prediction study.
    Matched MeSH terms: Cold Temperature*; Temperature
  15. Nyakuma BB, Mahyon NI, Chiong MS, Rajoo S, Pesiridis A, Wong SL, et al.
    Environ Sci Pollut Res Int, 2023 Aug;30(39):90522-90546.
    PMID: 37479929 DOI: 10.1007/s11356-023-28791-4
    The recovery and utilisation of waste heat from flue/exhaust gases (RU/WHFG) could potentially provide sustainable energy while curbing pollutant emissions. Over time, the RU/WHFG research landscape has gained significant traction and yielded innovative technologies, sustainable strategies, and publications. However, critical studies highlighting current advancements, publication trends, research hotspots, major stakeholders, and future research directions on RU/WHFG research remain lacking. Therefore, this paper presents a comprehensive bibliometric analysis and literature review of the RU/WHFG research landscape based on publications indexed in Scopus. Results showed that 123 publications and 2191 citations were recovered between 2010 and 2022. Publication trends revealed that the growing interest in RU/WHFG is mainly due to environmental concerns (e.g. pollution, global warming, and climate change), research collaborations, and funding availability. Stakeholder analysis revealed that numerous researchers, affiliations, and countries have actively contributed to the growth and development of RU/WHFG. Lin Fu and Tsinghua University (China) are the most prolific researchers and affiliations, whereas the National Natural Science Foundation of China (NSFC) and China are the most prolific funder and country, respectively. Funding availability from influential schemes such as NSFC has accounted for China's dominance. Keyword co-occurrence identified three major research hotspots, namely, thermal energy utilisation and management (cluster 1), integrated energy and resource recovery (cluster 2), and system analysis and optimisation (cluster 3). Literature review revealed that researchers are currently focused on maximising thermodynamic/energy efficiency, fuel minimisation, and emission reduction. Despite progress, research gaps remain in low-temperature/low-grade waste heat recovery, utilisation, storage, life cycle, and environmental impact analysis.
    Matched MeSH terms: Hot Temperature*; Temperature
  16. Nevame AYM, Emon RM, Malek MA, Hasan MM, Alam MA, Muharam FM, et al.
    Biomed Res Int, 2018;2018:1653721.
    PMID: 30065932 DOI: 10.1155/2018/1653721
    Occurrence of chalkiness in rice is attributed to genetic and environmental factors, especially high temperature (HT). The HT induces heat stress, which in turn compromises many grain qualities, especially transparency. Chalkiness in rice is commonly studied together with other quality traits such as amylose content, gel consistency, and protein storage. In addition to the fundamental QTLs, some other QTLs have been identified which accelerate chalkiness occurrence under HT condition. In this review, some of the relatively stable chalkiness, amylose content, and gel consistency related QTLs have been presented well. Genetically, HT effect on chalkiness is explained by the location of certain chalkiness gene in the vicinity of high-temperature-responsive genes. With regard to stable QTL distribution and availability of potential material resources, there is still feasibility to find out novel stable QTLs related to chalkiness under HT condition. A better understanding of those achievements is essential to develop new rice varieties with a reduced chalky grain percentage. Therefore, we propose the pyramiding of relatively stable and nonallelic QTLs controlling low chalkiness endosperm into adaptable rice varieties as pragmatic approach to mitigate HT effect.
    Matched MeSH terms: Hot Temperature*; Temperature
  17. Lee JY, Saat M, Chou C, Hashiguchi N, Wijayanto T, Wakabayashi H, et al.
    J Therm Biol, 2010 Feb;35(2):70-76.
    PMID: 28799915 DOI: 10.1016/j.jtherbio.2009.11.002
    The purpose of this study was to investigate ethnic differences in cutaneous thermal sensation thresholds and the inter-threshold sensory zone between tropical (Malaysians) and temperate natives (Japanese). The results showed that (1) Malaysian males perceived warmth on the forehead at a higher skin temperature (Tsk) than Japanese males (p<0.05), whereas cool sensations on the hand and foot were perceived at a lower Tsk in Malaysians (p<0.05); (2) Overall, the sensitivity to detect warmth was greater in Japanese than in Malaysian males; (3) The most thermally sensitive body region of Japanese was the forehead for both warming and cooling, while the regional thermal sensitivity of Malaysians had a smaller differential than that of Japanese; (4) The ethnic difference in the inter-threshold sensory zone was particularly noticeable on the forehead (1.9±1.2C for Japanese, 3.2±1.6°C for Malaysians, p<0.05). In conclusion, tropical natives had a tendency to perceive warmth at a higher Tsk and slower at an identical speed of warming, and had a wider range of the inter-threshold sensory zone than temperate natives.
    Matched MeSH terms: Cold Temperature; Hot Temperature; Skin Temperature
  18. Teh, Chiew Peng, Tan, Aileen Shau Hwai, Vengatesen, Thiyagarajan
    Trop Life Sci Res, 2016;27(11):111-116.
    The influence of the cool and warm temperatures on early life development and
    survival of tropical oyster, Crassostrea iredalei was studied. D-hinged larvae (day 1 larvae)
    were reared to three different temperatures (20°C, 27°C, and 34°C) for nine days. Oyster
    larvae reared in temperature 27°C, acted as control (ambient temperature). The highest
    survival rate occurred when the larvae were reared in 20°C and 27°C. Larvae reared at
    34°C exhibited reduced survival but increase in the growth rate. The growth rate in larvae
    reared in high temperature (34°C) was significantly higher compared to larvae reared in
    20°C and 27°C (p
    Matched MeSH terms: Cold Temperature; Hot Temperature; Temperature
  19. Normah, I., Cheow, C.S., Chong, C.L.
    Refined bleached and deodorized palm oil (RBDPO) was crystallized from the melt in a thermally controlled water bath at 14 and 22°C for 90 min. Slurries were withdrawn after 5, 15, 30, 60 and 90 min of crystallization for crystal morphology studies. Crystallization was also performed in a similar manner using a Labmax reactor connected to a FBRM detector to obtain the information on crystal count and size distribution during crystallization. Based on the shape of the crystals viewed under the microscope, all crystals appeared as needle shaped spherulitic β´- form at both crystallization temperatures studied. Crystals were slightly larger with increase in crystallization time and at higher crystallization temperature (22°C). Crystals size range between 4.34 to 22.29µm. FBRM recorded high count of crystals with increased in crystallization time and at lower temperature (14°C).
    Matched MeSH terms: Cold Temperature; Hot Temperature; Temperature
  20. Ullah I, Khan I, Shafie S
    Sci Rep, 2017 04 25;7(1):1113.
    PMID: 28442747 DOI: 10.1038/s41598-017-01205-5
    Unsteady mixed convection flow of Casson fluid towards a nonlinearly stretching sheet with the slip and convective boundary conditions is analyzed in this work. The effects of Soret Dufour, viscous dissipation and heat generation/absorption are also investigated. After using some suitable transformations, the unsteady nonlinear problem is solved by using Keller-box method. Numerical solutions for wall shear stress and high temperature transfer rate are calculated and compared with previously published work, an excellent arrangement is followed. It is noticed that fluid velocity reduces for both local unsteadiness and Casson parameters. It is likewise noticed that the influence of a Dufour number of dimensionless temperature is more prominent as compared to species concentration. Furthermore, the temperature was found to be increased in the case of nonlinear thermal radiation.
    Matched MeSH terms: Body Temperature Regulation; Hot Temperature; Temperature
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