Displaying publications 161 - 180 of 738 in total

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  1. Fulltext Development of Porous Epoxy Micro-Beads Using Ammonium Bicarbonate through a Single Epoxy Droplet in Corn Oil
    Leemsuthep A, Zakaria Z, Tanrattanakul V, Ramarad S, Muniyadi M, Jaruga T, et al.
    Materials (Basel), 2021 Apr 28;14(9).
    PMID: 33924997 DOI: 10.3390/ma14092282
    This paper explored the effects of ammonium bicarbonate and different ratios of epoxy to polyamide on the formation of porous epoxy micro-beads through a single epoxy droplet. A single drop of a mixture, consisting of epoxy, polyamide, and ammonium bicarbonate, was dropped into heated corn oil at a temperature of 100 °C. An epoxy droplet was formed due to the immiscibility of the epoxy mixture and corn oil. The ammonium bicarbonate within this droplet underwent a decomposition reaction, while the epoxy and polyamide underwent a curing reaction, to form porous epoxy micro-beads. The result showed that the higher ammonium bicarbonate content in the porous, epoxy micro-beads increased the decomposition rate up to 11.52 × 10-3 cm3/s. In addition, a higher total volume of gas was generated when a higher ammonium bicarbonate content was decomposed. This led to the formation of porous epoxy micro-beads with a smaller particle size, lower specific gravity, and better thermal stability. At an epoxy to polyamide ratio of 10:6, many smaller micro-beads, with particle sizes ranging from 201 to 400 μm, were obtained at an ammonium bicarbonate content of 10 phr. Moreover, the porous epoxy micro-beads with open pores were shown to have a low specific gravity of about 0.93 and high thermal stability at a high ammonium bicarbonate content. Based on the findings, it was concluded that porous epoxy micro-beads were successfully produced using a single epoxy droplet in heated corn oil, where their shape and particle size depended on the content of ammonium bicarbonate and the ratio of epoxy to polyamide used.
    Matched MeSH terms: Hot Temperature
  2. Development of a dry-reagent-based nucleic acid-sensing platform by coupling thermostabilised LATE-PCR assay to an oligonucleotide-modified lateral flow biosensor
    Ang GY, Yu CY, Chan KG, Singh KK, Chan Yean Y
    J Microbiol Methods, 2015 Nov;118:99-105.
    PMID: 26342435 DOI: 10.1016/j.mimet.2015.08.024
    In this study, we report for the first time the development of a dry-reagent-based nucleic acid-sensing platform by combining a thermostabilised linear-after-the-exponential (LATE)-PCR assay with a one-step, hybridisation-based nucleic acid lateral flow biosensor. The nucleic acid-sensing platform was designed to overcome the need for stringent temperature control during transportation or storage of reagents and reduces the dependency on skilled personnel by decreasing the overall assay complexity and hands-on time. The platform was developed using toxigenic Vibrio cholerae as the model organism due to the bacterium's propensity to cause epidemic and pandemic cholera. The biosensor generates result which can be visualised with the naked eyes and the limit of detection was found to be 1pg of pure genomic DNA and 10CFU/ml of toxigenic V. cholerae. The dry-reagent-based nucleic acid-sensing platform was challenged with 95 toxigenic V. cholerae, 7 non-toxigenic V. cholerae and 66 other bacterial strains in spiked stool sample and complete agreement was observed when the results were compared to that of monosialoganglioside (GM1)-ELISA. Heat-stability of the thermostabilised LATE-PCR reaction mixes at different storage temperatures (4-56°C) was investigated for up to 90days. The dry-reagent-based genosensing platform with ready-to-use assay components provides an alternative method for sequence-specific detection of nucleic acid without any cold chain restriction that is associated with conventional molecular amplification techniques.
    Matched MeSH terms: Hot Temperature
  3. Fulltext Development of an automation and control design system for lowland tropical greenhouses
    Wan Ishak, W.I., Hudzari, R.M., Tan, M.Y.
    Pertanika Journal of Science & Technology, 2013;21(2):365-374.
    MyJurnal
    Vapour pressure deficit (VPD) analysis introduces an approach to develop a better basis for the control of the environment of lowland greenhouses in Malaysia. The study of vapour pressure deficit (VPD) is to show air moisture conditions for plant production while taking into account different temperature levels. The purpose of this project is to develop a real-time automatic temperature and relative humidity control system in the lowland tropical greenhouse using a PIC16f876A microcontroller. The controller will then be used to monitor the temperature, relative humidity and VPD in the planting of Chili Kulai (Titisan 15). The fertigation system was introduced to the greenhouse to fertilize and irrigate the plant as well as to provide moisture to the environment. A swamp cooler was used to bring down the temperature and increase moisture content in the greenhouse. Ventilators were installed to remove the heat in the greenhouse. The study was carried out in an experimental greenhouse located at the Institute of Advanced Technology, Universiti Putra Malaysia (UPM).
    Matched MeSH terms: Hot Temperature
  4. Development of an efficient flat plate solar air heater for drying and water heating purposes
    Hanif M, Khattak M, Amin M, Ramzan M, Zakir S, Ullah S, et al.
    Sains Malaysiana, 2016;45:489-497.
    A 1.7 m2 flat plate solar air heater was designed and developed in the Department of Agricultural Mechanization, The University of Agriculture Peshawar, Pakistan in collaboration with the Department of Environmental Sciences, University of Peshawar, Pakistan. It was operated under an average solar irradiance of 0.9 kJ.m-2.h-1 in the month of September, 2013. It worked under an efficiency of 7.5 to 21%. The heat collected by the air heater was given to air flowing as a medium inside it. This hot air was given to a drying section and water heating tank for drying and water heating purposes. The drying section provided a temperature in the range of 40-50oC and humidity of 10-30% from 10:00 am to 3:00 pm. The water heating tank provides hot water with a temperature of 35- 45oC from 10:00 am to 5:00 pm. Furthermore, the drying section was used to dry apples, onions and persimmons. All the products showed a consistent moisture loss from them with an optimum drying rate. The two term exponential model showed that all the three products dried have a good correlation with drying time with R2 values higher than 0.90. It was concluded that flat plate solar air heaters is the best technology for water heating and drying purposes and is a good alternative of conventional energy sources.
    Matched MeSH terms: Hot Temperature
  5. Development of coconut pith chars towards high elemental mercury adsorption performance - Effect of pyrolysis temperatures
    Johari K, Saman N, Song ST, Cheu SC, Kong H, Mat H
    Chemosphere, 2016 Aug;156:56-68.
    PMID: 27160635 DOI: 10.1016/j.chemosphere.2016.04.114
    In this study, chars from coconut pith (CP) were prepared aiming for superior adsorption towards elemental mercury (Hg(o)). The yield, proximate analysis, textural characteristics, surface functional groups and elemental composition analyses of the chars produced at pyrolysis temperature of 300 °C, 500 °C, 700 °C and 900 °C were compared. The surface area, pore volume, ash and carbon content of chars increased, while the yield and moisture content decreased with increasing pyrolysis temperatures. The changing of physical and chemical properties of the chars produced at variety pyrolysis temperature was much effect on the Hg(o) adsorption performance and definitely provides important information on the Hg(o) adsorption mechanism. The highest Hg(o) adsorption capacity was observed for CP900 (6067.49 μg/g), followed by CP700 (2395.98 μg/g), CP500 (289.76 μg/g), CP300 (1.68 μg/g), and CP (0.73 μg/g). The equilibrium data were well described by the Freundlich adsorption isotherm model. The pseudo-second order best described the kinetic data of the Hg(o) adsorption onto CP and CP300. For chars produced at higher pyrolysis temperature, however, the pseudo-zero order and pseudo-second order fitted well for the adsorption and breakthrough regions, respectively. The Hg(o) adsorption capacity of chars obtained from high pyrolysis temperature of CP significantly outperformed the commercial activated carbon (Darco KB-B) as well as superior to chars reported in the literature indicating the CP can be used as a precursor for preparation of chars as elemental mercury adsorbents.
    Matched MeSH terms: Hot Temperature
  6. Fulltext Development of physical workload and heat stress questionnaire for construction industry in Malaysia
    Solehan Imran Shariffudin, Jafri Mohd. Rohani, Mohd Firdaus Mohd Taib, Roseni Abd. Aziz
    Journal of Occupational Safety and Health, 2016;13(2):93-97.
    MyJurnal
    Geographically, Malaysia is situated in the equatorial region, thus having a climate of hot and humid throughout the
    year. Effect of heat stress and physical work load at construction industry need to be investigated because of the high number of
    accidents. Thus, perception of physical workload and heat stress by the construction workers in Malaysia needed to be investigated
    and documented. The aim of this paper is to establish a set of questionnaires containing the item generation regarding on physical
    workload and the heat stress perception of construction workers. Physical workload factors such as fatigue, risks, concentration,
    work rhythm, responsibility, satisfaction, and autonomy are inserted as the items in assessing the physical workload. While heat
    stress are assessed using heat risk factors such as temperature, humidity, heat radiation, air movement, workload, clothing and
    acclimatisation. A questionnaire has been developed resulted from various reviewing of literatures on physical workload and heat
    stress and better suited to the Malaysia working environment.
    Matched MeSH terms: Hot Temperature
  7. Fulltext Development of pulsating twin jets mechanism for mixing flow heat transfer analysis
    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*
  8. Diagnostic models to predict nuclear DNA and mitochondrial DNA recovery from incinerated teeth
    Rahmat RA, Humphries MA, Saedon NA, Self PG, Linacre AMT
    Int J Legal Med, 2023 Sep;137(5):1353-1360.
    PMID: 37306739 DOI: 10.1007/s00414-023-03017-x
    Teeth are frequently used for human identification from burnt remains, as the structure of a tooth is resilient against heat exposure. The intricate composition of hydroxyapatite (HA) mineral and collagen in teeth favours DNA preservation compared to soft tissues. Regardless of the durability, the integrity of the DNA structure in teeth can still be disrupted when exposed to heat. Poor DNA quality can negatively affect the success of DNA analysis towards human identification. The process of isolating DNA from biological samples is arduous and costly. Thus, an informative pre-screening method that could aid in selecting samples that can potentially yield amplifiable DNA would be of excellent value. A multiple linear regression model to predict the DNA content in incinerated pig teeth was developed based on the colourimetry, HA crystallite size and quantified nuclear and mitochondrial DNA. The chromaticity a* was found to be a significant predictor of the regression model. This study outlines a method to predict the viability of extracting nuclear and mitochondrial DNA from pig teeth that were exposed to a wide range of temperatures (27 to 1000 °C) with high accuracy (99.5-99.7%).
    Matched MeSH terms: Hot Temperature
  9. Dielectric Spectroscopy of Palm Olein During Batch Deep Frying and Their Relation with Degradation Parameters
    Ibrahim NUA, Abd Aziz S, Hashim N, Jamaludin D, Khaled AY
    J Food Sci, 2019 Apr;84(4):792-797.
    PMID: 30861127 DOI: 10.1111/1750-3841.14436
    Total polar compounds (TPC) and free fatty acids (FFA) are important indicators in evaluating the quality of frying oil. Conventional methods to determine TPC and FFA are often time consuming, involved laboratory analyses which required skilled personnel and used substantial amount of harmful solvent. In this study, dielectric spectroscopy technique was used to investigate the relation between dielectric property of refined, bleached and deodorized palm olein (RBDPO) during deep frying with TPC and FFA. In total, 150 batches of French fries were intermittently fried at 185 ± 5 °C for 7 hr a day over 5 consecutive days. A total of 30 frying oil samples were collected. The dielectric property of frying oil samples were measured using impedance analyzer with frequencies ranging from 100 Hz to 10 MHz. The TPC of frying oil samples were measured with a Testo 270, while the FFA analysis was done using Malaysian Palm Oil Board (MPOB) test method. Results showed that dielectric constant, TPC and FFA of RBDPO increased as the frying time increased. Dielectric constant increased from 3.09 to 3.17, while TPC and FFA increased from 9.96 to 19.52 and from 0.08% to 0.36%, respectively. Partial least square (PLS) analysis produced good prediction of TPC and FFA with the application of genetic algorithm (GA). Model developed for prediction of TPC and FFA yielded highly significant correlation with R2 of 0.91 and 0.95, respectively and both had root mean square error in cross-validation (RMSECV) of 1.06%. This study demonstrates the potential of dielectric spectroscopy in monitoring palm olein degradation during frying. PRACTICAL APPLICATION: The application of dielectric spectroscopy to detect degradation of palm olein during frying was studied. The dielectric property of palm olein during frying has successfully correlated with TPC and FFA. The model developed in this study could be used for the development of a sensing system for palm olein degradation monitoring.
    Matched MeSH terms: Hot Temperature
  10. Dietary exposure to heterocyclic amines in high-temperature cooked meat and fish in Malaysia
    Jahurul MH, Jinap S, Ang SJ, Abdul-Hamid A, Hajeb P, Lioe HN, et al.
    Food Addit Contam Part A Chem Anal Control Expo Risk Assess, 2010 Aug;27(8):1060-71.
    PMID: 20589547 DOI: 10.1080/19440041003801190
    The intake of heterocyclic amines is influenced by the amount and type of meat and fish ingested, frequency of consumption, cooking methods, cooking temperature, and duration of cooking. In this study, the dietary intake of heterocyclic amines in Malaysia and their main sources were investigated. Forty-two samples of meat and fish were analysed by high-performance liquid chromatography with photodiode array detector to determine the concentration of the six predominant heterocyclic amines, namely: 2-amino-3-methylimidazo[4,5-f] quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f] quinoline(MeIQ), 2-amino-3,8-dimethylimidazo[4,5-f] quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f] quinoxaline (4,8-DiMeIQx), 2-amino-3,7,8-trimethylimidazo[4,5-f] quinoxaline (7,8-DiMeIQx), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Dietary intake data were obtained using a food-frequency questionnaire when interviewing 600 Malaysian respondents. The level of total heterocyclic amines in food samples studies ranged from not detected to 38.7 ng g(-1). The average daily intake level of heterocyclic amine was 553.7 ng per capita day(-1). The intake of PhIP was the highest, followed by MeIQx and MeIQ. The results reveal that fried and grilled chicken were the major dietary source of heterocyclic amines in Malaysia. However, the heterocyclic amine intake by the Malaysian population was lower than those reported from other regions.
    Matched MeSH terms: Hot Temperature/adverse effects*
  11. Dietary supplementation of Zingiber officinale and Zingiber zerumbet to heat-stressed broiler chickens and its effect on heat shock protein 70 expression, blood parameters and body temperature
    Hasheimi SR, Zulkifli I, Somchit MN, Zunita Z, Loh TC, Soleimani AF, et al.
    J Anim Physiol Anim Nutr (Berl), 2013 Aug;97(4):632-8.
    PMID: 22533311 DOI: 10.1111/j.1439-0396.2012.01302.x
    The present study was conducted to assess the effects of dietary supplementation of Zingiber officinale and Zingiber zerumbet and to heat-stressed broiler chickens on heat shock protein (HSP) 70 density, plasma corticosterone concentration (CORT), heterophil to lymphocyte ratio (HLR) and body temperature. Beginning from day 28, chicks were divided into five dietary groups: (i) basal diet (control), (ii) basal diet +1%Z. zerumbet powder (ZZ1%), (iii) basal diet +2%Z. zerumbet powder (ZZ2%), (iv) basal diet +1%Z. officinale powder (ZO1%) and (v) basal diet +2%Z. officinale powder (ZO2%). From day 35-42, heat stress was induced by exposing birds to 38±1°C and 80% RH for 2 h/day. Irrespective of diet, heat challenge elevated HSP70 expression, CORT and HLR on day 42. On day 42, following heat challenge, the ZZ1% birds showed lower body temperatures than those of control, ZO1% and ZO2%. Neither CORT nor HLR was significantly affected by diet. The ZO2% and ZZ2% diets enhanced HSP70 expression when compared to the control groups. We concluded that dietary supplementation of Z. officinale and Z. zerumbet powder may induce HSP70 reaction in broiler chickens exposed to heat stress.
    Matched MeSH terms: Hot Temperature/adverse effects*
  12. Dietary supplementation of a mixture of Lactobacillus strains enhances performance of broiler chickens raised under heat stress conditions
    Faseleh Jahromi M, Wesam Altaher Y, Shokryazdan P, Ebrahimi R, Ebrahimi M, Idrus Z, et al.
    Int J Biometeorol, 2016 Jul;60(7):1099-110.
    PMID: 26593972 DOI: 10.1007/s00484-015-1103-x
    High ambient temperature is a major problem in commercial broiler production in the humid tropics because high producing broiler birds consume more feed, have higher metabolic activity, and thus higher body heat production. To evaluate the effects of two previously isolated potential probiotic strains (Lactobacillus pentosus ITA23 and Lactobacillus acidophilus ITA44) on broilers growing under heat stress condition, a total of 192 chicks were randomly allocated into four treatment groups of 48 chickens each as follows: CL, birds fed with basal diet raised in 24 °C; PL, birds fed with basal diet plus 0.1 % probiotic mixture raised in 24 °C; CH, birds fed with basal diet raised in 35 °C; and PH, birds fed with basal diet plus 0.1 % probiotic mixture raised in 35 °C. The effects of probiotic mixture on the performance, expression of nutrient absorption genes of the small intestine, volatile fatty acids (VFA) and microbial population of cecal contents, antioxidant capacity of liver, and fatty acid composition of breast muscle were investigated. Results showed that probiotic positively affected the final body weight under both temperature conditions (PL and PH groups) compared to their respective control groups (CL and CH). Probiotic supplementation numerically improved the average daily gain (ADG) under lower temperature, but significantly improved ADG under the higher temperature (P 
    Matched MeSH terms: Hot Temperature
  13. Differences in dry-bulb temperature do not influence moderate-duration exercise performance in warm environments when vapor pressure is equivalent
    Lei TH, Schlader ZJ, Che Muhamed AM, Zheng H, Stannard SR, Kondo N, et al.
    Eur J Appl Physiol, 2020 Apr;120(4):841-852.
    PMID: 32072226 DOI: 10.1007/s00421-020-04322-8
    PURPOSE: Recent studies have determined that ambient humidity plays a more important role in aerobic performance than dry-bulb temperature does in warm environments; however, no studies have kept humidity constant and independently manipulated temperature. Therefore, the purpose of this study was to determine the contribution of dry-bulb temperature, when vapor pressure was matched, on the thermoregulatory, perceptual and performance responses to a 30-min cycling work trial.

    METHODS: Fourteen trained male cyclists (age: 32 ± 12 year; height: 178 ± 6 cm; mass: 76 ± 9 kg; [Formula: see text]: 59 ± 9 mL kg-1 min-1; body surface area: 1.93 ± 0.12 m2; peak power output: 393 ± 53 W) volunteered, and underwent 1 exercise bout in moderate heat (MOD: 34.9 ± 0.2 °C, 50.1 ± 1.1% relative humidity) and 1 in mild heat (MILD: 29.2 ± 0.2 °C, 69.4 ± 0.9% relative humidity) matched for vapor pressure (2.8 ± 0.1 kPa), with trials counterbalanced.

    RESULTS: Despite a higher weighted mean skin temperature during MOD (36.3 ± 0.5 vs. 34.5 ± 0.6 °C, p 

    Matched MeSH terms: Hot Temperature*
  14. Fulltext Differences in thermostable actin profile of goat meat as observed in twodimensional gel electrophoresis (2DE)
    Sarah, S.A., Amin, I., Mokhtar, N.F.K., Sazili, A.Q., Karsani S.A.
    International Food Research Journal, 2013;20(2):897-901.
    MyJurnal
    Different heat treatments, (1) chilled, 4°C (2) boiled at 100°C for 30 min and (3) autoclaved at 121°C at 15 psi for 20 min were employed on goat meat to mimic domestic and industrial cooking. The effects on intensity of actin proteins was observed using two-dimensional gel electrophoresis where significant differences (p>0.05) were observed in the spot intensity between chilled and boiled samples, similarly in chilled and autoclaved samples. However, no significant difference was observed between boiled and autoclaved samples. The slight changes observed in the cooking of meat confirmed that actin protein is susceptible to denaturation cause by heat. MALDI-TOF/TOF analysis revealed the peptide-mass fingerprint between positions 21 – 374 that not affected by heat treatment. Peptides from this position merit the candidature of actin as putative thermostable marker for detecting goat meat (chevon) in food product.
    Matched MeSH terms: Hot Temperature
  15. Direct purification of recombinant hepatitis B core antigen from two different pre-conditioned unclarified Escherichia coli feedstocks via expanded bed adsorption chromatography
    Ng MY, Tan WS, Abdullah N, Ling TC, Tey BT
    J Chromatogr A, 2007 Nov 16;1172(1):47-56.
    PMID: 17945242
    Direct recovery of hepatitis B core antigen (HBcAg) from unclarified Escherichia coli homogenates via expanded bed adsorption chromatography (EBA) has been explored in this study. Streamline DEAE was selected as the anion exchanger to recover HBcAg from heat-treated and non-heat-treated unclarified feedstocks. The use of anion-exchanger for direct extraction of proteins from unclarified feedstock is not preferred due to lack of specificity of its ligand. In this study, thermal treatment of the unclarified feedstock at 60 degrees C has resulted in 1.2- and 1.8-fold increases in yield and purity of HBcAg, respectively, compared with that purified from non-heat-treated feedstock. Heating the crude feedstock has resulted in denaturation and precipitation of contaminants in the feedstock, hence reducing non-specific interactions between the cell debris and adsorbent. The selectivity of the anion-exchanger has also been increased as shown in the breakthrough curve obtained. Enzyme-linked immunosorbent assay showed that the antigenicity of the HBcAg from heat-treated unclarified feedstock is still preserved.
    Matched MeSH terms: Hot Temperature
  16. Fulltext Diversity of thermophiles in a Malaysian hot spring determined using 16S rRNA and shotgun metagenome sequencing
    Chan CS, Chan KG, Tay YL, Chua YH, Goh KM
    Front Microbiol, 2015;6:177.
    PMID: 25798135 DOI: 10.3389/fmicb.2015.00177
    The Sungai Klah (SK) hot spring is the second hottest geothermal spring in Malaysia. This hot spring is a shallow, 150-m-long, fast-flowing stream, with temperatures varying from 50 to 110°C and a pH range of 7.0-9.0. Hidden within a wooded area, the SK hot spring is continually fed by plant litter, resulting in a relatively high degree of total organic content (TOC). In this study, a sample taken from the middle of the stream was analyzed at the 16S rRNA V3-V4 region by amplicon metagenome sequencing. Over 35 phyla were detected by analyzing the 16S rRNA data. Firmicutes and Proteobacteria represented approximately 57% of the microbiome. Approximately 70% of the detected thermophiles were strict anaerobes; however, Hydrogenobacter spp., obligate chemolithotrophic thermophiles, represented one of the major taxa. Several thermophilic photosynthetic microorganisms and acidothermophiles were also detected. Most of the phyla identified by 16S rRNA were also found using the shotgun metagenome approaches. The carbon, sulfur, and nitrogen metabolism within the SK hot spring community were evaluated by shotgun metagenome sequencing, and the data revealed diversity in terms of metabolic activity and dynamics. This hot spring has a rich diversified phylogenetic community partly due to its natural environment (plant litter, high TOC, and a shallow stream) and geochemical parameters (broad temperature and pH range). It is speculated that symbiotic relationships occur between the members of the community.
    Matched MeSH terms: Hot Temperature
  17. Fulltext Double Pulse Resistance Spot Welding of Dual Phase Steel: Parametric Study on Microstructure, Failure Mode and Low Dynamic Tensile Shear Properties
    Soomro IA, Pedapati SR, Awang M
    Materials (Basel), 2021 Feb 08;14(4).
    PMID: 33567606 DOI: 10.3390/ma14040802
    Resistance spot welding (RSW) of dual phase (DP) steels is a challenging task due to formation of brittle martensitic structure in the fusion zone (FZ), resulting in a low energy capacity of the joint during high-rate loading. In the present study, in situ postweld heat treatment (PWHT) was carried out by employing a double pulse welding scheme with the aim of improving the mechanical performance of DP590 steel resistance spot weld joint. Taguchi method was used to optimize in situ PWHT parameters to obtain maximum peak load and failure energy. Experiments were designed based on orthogonal array (OA) L16. Mechanical performance was evaluated in terms of peak load and failure energy after performing low dynamic tensile shear (TS) test. Microstructural characterization was carried out using a scanning electron microscope (SEM). The results show that improvements of 17 and 86% in peak load and failure energy, respectively, were achieved in double-pulse welding (DPW) at optimum conditions compared to traditional single-pulse welding (SPW). The improvement in mechanical performance resulted from (i) enlargement of the FZ and (ii) improved weld toughness due to tempering of martensite in the FZ and subcritical heat affected zone (SCHAZ). These factors are influenced by heat input, which in turn depends upon in situ PWHT parameters.
    Matched MeSH terms: Hot Temperature
  18. Fulltext Drying characteristics and quality evaluation of kiwi slices under hot air natural convective drying method
    Siew, E.S., Chin, S.K., Soon, W.L.
    International Food Research Journal, 2015;22(6):2188-2195.
    MyJurnal
    Dried kiwis are highly needed in food industries such as cereals, ice-cream, beverages and supplemental products. In this paper, drying characteristics and product quality of hot air dried kiwi slices were studied. Hot air drying of kiwi slices was investigated at drying temperature ranged from 40°C to 60°C and slice thickness of 0.3 cm and 0.6 cm. Results showed that drying of kiwi slices at higher drying temperature stimulates the drying rate, which leads to shorter total drying time required. The drying kinetics of kiwi slices was best fitted by approximation diffusion model. Increased in drying temperatures and slice thickness of kiwi enhanced the effective moisture diffusivity (Deff). The highest Deff of the kiwi slices was recorded as 1.5681 x 10-8 m2 /min at slice thickness of 0.6 cm. In terms of quality analysis, kiwi slices dried at temperature of 60°C with fastest drying rate retained most of the Total Phenolic Content (TPC) in the dried sample. However, drying of kiwi slices at high drying temperature deteriorated the vitamin C content of kiwi slices due to thermal degradation. Thinner kiwi slices could preserve higher amount of TPC and vitamin C during the drying process, yet the best hot air drying temperature for drying of kiwi slices could be relied on the consumers’ preference based on the dried product quality as reported in the current work.
    Matched MeSH terms: Hot Temperature
  19. Drying kinetics and stabilization of sewage sludge in lagoon in hot climate
    Idris A, Yen OB, Hamid MH, Baki AM
    Water Sci Technol, 2002;46(9):279-86.
    PMID: 12448479
    A sludge lagoon has been adopted as a simple and cost effective method for dewatering of sludge. The processes occurring in a sludge lagoon include thickening, dewatering, storage and stabilization; all happening simultaneously. The objective of this study is to determine the dewatering and drying rates at pilot-scale which occur in a lagoon having different design configurations. Two types of sludge lagoons with different initial sludge depth (0.75 m and 0.375 m) were investigated to measure the drying behavior and drying efficiency. The first design is a sludge lagoon with a clay bottom where the dewatering mechanisms are decanting supernatant and evaporation. The second design is a sludge lagoon installed with a sand and underdrains system, where the dewatering mechanisms are filtration or draining and evaporation. Sludge drying kinetic models with high fitness were plotted to describe the sludge drying behavior. Drying of sludge in a sludge lagoon with a clay bottom can best be described by an exponential function. Whereas, drying of sludge in a sludge lagoon with sand and underdrains system followed a logarithmic function. A lagoon designed with sand and underdrains system and having shallower sludge depth was the most efficient. The reduction in volatile solids was lower than 4% during the study period. The drying process proceeded with an increase in dryness and decline in pH value.
    Matched MeSH terms: Hot Temperature
  20. Durability of induced heat tolerance by short-term heat challenge at broilers marketing age
    Soleimani AF, Kasim A, Alimon AR, Zulkifli I
    Pak J Biol Sci, 2008 Sep 01;11(17):2163-6.
    PMID: 19266934
    A trial was conducted to determine the influence of short-term exposure to high ambient temperature at 28 and 35 days of age on deep body temperatures (Tb) and subsequent growth of birds until 42 days of age. A total of 90 day old chicks were reared in stainless steel battery cages and were assigned at random into 18 pens of 5 birds each, with 9 pens containing males and another 9 pens containing females. Three treatment groups, each represented by 3 male and 3 female pens, were represented by T1 without any heat exposure, T2 with heat exposure starting at day 28 and T3 with heat exposure starting at day 35. Heat stress was defined as 180 min exposure to 35 +/- 1 degrees C. Tb and body weights were measured at 35, 37 and 39 days of age immediately following heat exposure. Heat stress resulted in higher Tb and Onset of heat stress at 28 days resulted in significantly lower Tb than onset of heat stress at 35 days. Lower Tb in T2 than T3 permitted recovery in body weight at 42 days. Sexes responded similarly to heat stress.
    Matched MeSH terms: Hot Temperature*
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