Displaying publications 681 - 700 of 2919 in total

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  1. Wahib N, Zulkepely NN, Mat Nawi SN, Amin YM, Ling YS, Abdul Sani SF, et al.
    Appl Radiat Isot, 2015 Nov;105:158-162.
    PMID: 26313622 DOI: 10.1016/j.apradiso.2015.08.025
    Over the past decade and more, considerable interest has been shown in the thermoluminescence (TL) properties of silica-based single-mode optical fibres, in particular investigating potential ionising radiation dosimetry applications. Herein, study has been made of TL glow curve, dose response, reproducibility and fading of 6mol% Ge-doped silica, fabricated in-house and produced in the form of cylindrical fibres. Three different pairings of doped-core and silica cladding diameters were produced: (40, 241)µm, (80, 483)µm and (100, 604)µm. The TL results were compared against that of TLD-100, one of the most sensitive commercially available LiF-based TL media. For all three pairings of diameters, closely similar TL glow curve were obtained, formed of a single peaked structure with a maximum TL yield located between the temperatures 250 and 310°C. The TL yield of the fibres were linear over the range of doses investigated, from 1Gy up to 10Gy, their dose response exceeding that of TLD-100, the samples also being found to be reusable, without evidence of degradation.
    Matched MeSH terms: Temperature
  2. Khan AF, Sajjad W, Rahim NA
    Recent Pat Nanotechnol, 2016;10(1):77-82.
    PMID: 27018275
    BACKGROUND: It is well-known that multi-layer films with nanostructure can give novel properties by interfacial phenomenon and quantum confinement effects. Nanostructured multi-layer thin films are presently being analyzed for their vast applications in the area of optoelectronics technology particularly photovoltaics. Hereof, two dimensional thin films with nanostructure are of prime importance due to their structure dependent optical, electrical, and opto-electronic properties. It has been revealed that these films exhibit quantum confinement effects with band gap engineering. The main focus of the research is to evaluate the effect on structural and optical properties with number of layers.

    METHODS: Nanostructured SnO2-Ge multi-layer thin films were fabricated using electron beam evaporation and resistive heating techniques. Alternate layers of SnO2 and Ge were deposited on glass substrate at a substrate temperature of 300 °C in order to obtain uniform and homogeneous deposition. The substrate temperature of 300 °C has been determined to be effective for the deposition of these multi-layer films from our previous studies. The films were characterized by investigating their structural and optical properties. The structural properties of the as-deposited films were characterized by Rutherford Backscattering Spectroscopy (RBS) and Raman spectroscopy and optical properties by Ultra-Violet-Near infrared (UV-VIS-NIR) spectroscopy.

    RESULTS: RBS studies confirmed that the layer structure has been effectively formed. Raman spectroscopy results show that the peaks of both Ge and SnO2 shifts towards lower wavenumbers (in comparison with bulk Ge and SnO2, suggesting that the films consist of nanostructures and demonstrate quantum confinement effects. UV-VIS-NIR spectroscopy showed an increase in the band gap energy of Ge and SnO2 and shifting of transmittance curves toward higher wavelength by increasing the number of layers. The band gap lies in the range of 0.9 to 1.2 eV for Ge, while for SnO2, it lies between 1.7 to 2.1 eV.

    CONCLUSION: Analysis of results suggests that the nanostructured SnO2-Ge multi-layer thin film can work as heterojunction materials with quantum confinement effects. Accordingly, the present SnO2-Ge multi-layer films may be employed for photovoltaic applications. Few relevant patents to the topic have been reviewed and cited.

    Matched MeSH terms: Temperature
  3. Al-Doghachi FA, Islam A, Zainal Z, Saiman MI, Embong Z, Taufiq-Yap YH
    PLoS One, 2016;11(1):e0145862.
    PMID: 26745623 DOI: 10.1371/journal.pone.0145862
    A highly active and stable nano structured Pt/Mg1-xNixO catalysts was developed by a simple co-precipitation method. The obtained Pt/Mg1-xNixO catalyst exhibited cubic structure nanocatalyst with a size of 50-80 nm and realized CH4 and CO2 conversions as high as 98% at 900°C with excellent stability in the dry reforming of methane. The characterization of catalyst was performed using various kinds of analytical techniques including XRD, BET, XRF, TPR-H2, TGA, TEM, FESEM, FT-IR, and XPS analyses. Characterization of spent catalyst further confirms that Pt/Mg1-xNixO catalyst has high coke-resistance for dry reforming. Thus, the catalyst demonstrated in this study, offers a promising catalyst for resolving the dilemma between dispersion and reducibility of supported metal, as well as activity and stability during high temperature reactions.
    Matched MeSH terms: Temperature
  4. Dahlan ND, Gital YY
    Appl Ergon, 2016 May;54:169-76.
    PMID: 26851476 DOI: 10.1016/j.apergo.2015.12.008
    The study was done to identify affective and sensory responses observed as a result of hysteresis effects in transient thermal conditions consisting of warm-neutral and neutral - warm performed in a quasi-experiment setting. Air-conditioned building interiors in hot-humid areas have resulted in thermal discomfort and health risks for people moving into and out of buildings. Reports have shown that the instantaneous change in air temperature can cause abrupt thermoregulation responses. Thermal sensation vote (TSV) and thermal comfort vote (TCV) assessments as a consequence of moving through spaces with distinct thermal conditions were conducted in an existing single-story office in a hot-humid microclimate, maintained at an air temperature 24 °C (± 0.5), relative humidity 51% (± 7), air velocity 0.5 m/s (± 0.5), and mean radiant temperature (MRT) 26.6 °C (± 1.2). The measured office is connected to a veranda that showed the following semi-outdoor temperatures: air temperature 35 °C (± 2.1), relative humidity 43% (± 7), air velocity 0.4 m/s (± 0.4), and MRT 36.4 °C (± 2.9). Subjective assessments from 36 college-aged participants consisting of thermal sensations, preferences and comfort votes were correlated against a steady state predicted mean vote (PMV) model. Local skin temperatures on the forehead and dorsal left hand were included to observe physiological responses due to thermal transition. TSV for veranda-office transition showed that no significant means difference with TSV office-veranda transition were found. However, TCV collected from warm-neutral (-0.24, ± 1.2) and neutral-warm (-0.72, ± 1.3) conditions revealed statistically significant mean differences (p < 0.05). Sensory and affective responses as a consequence of thermal transition after travel from warm-neutral-warm conditions did not replicate the hysteresis effects of brief, slightly cool, thermal sensations found in previous laboratory experiments. These findings also indicate that PMV is an acceptable alternative to predict thermal sensation immediately after a down-step thermal transition (≤ 1 min exposure duration) for people living in a hot-humid climate country.
    Matched MeSH terms: Body Temperature Regulation/physiology; Hot Temperature; Skin Temperature
  5. Poh BL, Khairuddean M
    Talanta, 1996 Oct;43(10):1727-31.
    PMID: 18966659
    A non-cyclic tetrameric structure has been suggested for calcichrome (calcion). This structure is consistent with its mass spectrum, proton NMR spectrum, elemental composition and complexing ability with polyaromatic hydrocarbons in water. The stability constants of the 1:1 complexes formed between calcichrome and seven polyaromatic hydrocarbons in water at room temperature have been measured.
    Matched MeSH terms: Temperature
  6. Tan CT
    Med J Malaysia, 1994 Mar;49(1):68-73.
    PMID: 8057994
    This is a study of 13 Malaysian patients with clinically definite Multiple sclerosis (MS) subjected to a hot bath test with VEPs, BAEPs, median nerve SSEPs before and after heating. Five patients (38%) developed neurological changes with the rise in body temperature. There was an average of 0.46 new sign per patient. Four patients had motor disturbances attributed mainly to aggravation of spinal cord dysfunction. Two patients had additional visual deterioration, one patient has associated VEP change. This study shows that though Uhthoff's phenomenon has not been noted in the reports of Asian MS patients, when subjected to rigorous testing, Asian MS patients also show sensitivity to body temperature change. However, the percentage of positivity of the hot bath test is much lower than that reported for Caucasians. Thus this study shows further differences between Asian and Caucasian MS patients.
    Matched MeSH terms: Body Temperature*; Hot Temperature*
  7. Belhaj AF, Elraies KA, Alnarabiji MS, Abdul Kareem FA, Shuhli JA, Mahmood SM, et al.
    Chem Eng J, 2021 Feb 15;406:127081.
    PMID: 32989375 DOI: 10.1016/j.cej.2020.127081
    Throughout the application of enhanced oil recovery (EOR), surfactant adsorption is considered the leading constraint on both the successful implementation and economic viability of the process. In this study, a comprehensive investigation on the adsorption behaviour of nonionic and anionic individual surfactants; namely, alkyl polyglucoside (APG) and alkyl ether carboxylate (AEC) was performed using static adsorption experiments, isotherm modelling using (Langmuir, Freundlich, Sips, and Temkin models), adsorption simulation using a state-of-the-art method, binary mixture prediction using the modified extended Langmuir (MEL) model, and artificial neural network (ANN) prediction. Static adsorption experiments revealed higher adsorption capacity of APG as compared to AEC, with sips being the most fitted model with R2 (0.9915 and 0.9926, for APG and AEC respectively). It was indicated that both monolayer and multilayer adsorption took place in a heterogeneous adsorption system with non-uniform surfactant molecules distribution, which was in remarkable agreement with the simulation results. The (APG/AEC) binary mixture prediction depicted contradictory results to the experimental individual behaviour, showing that AEC had more affinity to adsorb in competition with APG for the adsorption sites on the rock surface. The adopted ANN model showed good agreement with the experimental data and the simulated adsorption values for APG and AEC showed a decreasing trend as temperature increases. Simulating the impact of binary surfactant adsorption can provide a tremendous advantage of demonstrating the binary system behaviour with less experimental data. The utilization of ANN for such prediction procedure can minimize the experimental time, operating cost and give feasible predictions compared to other computational methods. The integrated workflow followed in this study is quite innovative as it has not been employed before for surfactant adsorption studies.
    Matched MeSH terms: Temperature
  8. Mior Azmai, W. N. S., Abdul Latif, N. S., Md Zain, N.
    MyJurnal
    Tomatoes require appropriate environment to stay sturdy due to earlier decay process. Deterioration causes short shelf life of tomatoes with unfavourable quality, resulting in potential rejection by customers. The objective of the study is to observe the effect of combined coatings of chitosan (Ch) and cinnamic acid (CA) in extending the tomato shelf life. Layer by layer coating of chitosan prior to the cinnamic acid (single coating for each) were applied on fresh graded tomato at two maturity stages; breaker and turning. Twelve days observations at ambient temperature with three-day intervals were recorded. Combined coating of chitosan and cinnamic acid were expected to influence firmness, TSS value, hue angle and weight loss. Results showed that a combined coating of 1.0% Ch + 3 mM CA has significant increament at breaker stage to firmness (8.26 N), hue angle (60.42%) and weight loss value (6.51%) compared to untreated tomato whereas for turning stage, the results showed there were no significant different in all parameters observed except the changes of fruit sweetness (TSS). 1.0% Ch + 4 mM CA show highest TSS value, 3.48% indicating 21% difference than untreated tomato (3.27%). Cinnamic acid helped chitosan in improving coating ability by serving better barrier from pathogen and oxidative gas penetration to prevent earlier spoilage problem.
    Matched MeSH terms: Temperature
  9. Ang TN, Young BR, Burrell R, Taylor M, Aroua MK, Baroutian S
    Chemosphere, 2021 Feb;264(Pt 2):128535.
    PMID: 33045509 DOI: 10.1016/j.chemosphere.2020.128535
    The emission of waste anaesthetic gas is a growing contributor to global warming and remains a factor in atmospheric ozone depletion. Volatile anaesthetics in medical waste gases could be removed via adsorption using suitable activated carbon materials possessing an enhanced affinity to anaesthetic molecules. In this work, the effects of surface physical and chemical properties on sevoflurane adsorption were investigated by oxidative hydrothermal surface modification of a commercial activated carbon using only distilled water. The hydrothermal surface modification was carried out at different treatment temperatures (150-300 °C) for varying durations (10-30 min), and adsorption was conducted under fixed conditions (bed depth = 10 cm, inlet concentration = 528 mg/L, and flow rate = 3 L/min). The hydrothermal treatment generally increased the BET surface area of the activated carbons. At oxidation temperatures above 200 °C, the micropore volume of the samples diminished. The relative amount of surface oxygen was enriched as the treatment temperature increased. Treatment duration did not significantly affect the introduction of relative amount of surface oxygen, except at higher temperatures. There were no new types of functional groups introduced. However, disappearance and re-formation of oxygen functional groups containing C-O structures (as in hydroxyl and ether groups) occurred when treatment temperature was increased from 150 to 200 °C, and when treatments were conducted above 200 °C, respectively. The ester/acetal groups were enriched under the temperature range studied. The findings suggested that the re-formation of surface oxygen functionalities might lead to the development of functional groups that improve sevoflurane adsorption.
    Matched MeSH terms: Temperature
  10. Fitriani N, Kusuma MN, Wirjodirdjo B, Hadi W, Hermana J, Ni'matuzahroh, et al.
    Heliyon, 2020 Sep;6(9):e04967.
    PMID: 33015386 DOI: 10.1016/j.heliyon.2020.e04967
    In a slow sand filter, a biological layer consisting of alluvial mud and various types of microorganisms grows and attaches to the sand media and forms a matrix called schmutzdecke. Changes to several factors, including the quality of raw water, filtration speed, and the addition of media, affect the performance of the slow sand filter unit in producing treated water. Geotextiles can be equipped to improve the performance of a slow sand filter in removing pollutants. The selection of several factors that affect slow sand filter performance can be used as a starting point for the engineering system to determine the best pattern of performance behavior. This approach was carried out by looking at the dynamic behavior patterns of slow sand filter system performance in treating raw water. This research has not yet been conducted extensively. The dynamic behavior pattern approach to the performance of the slow sand filter unit was used to obtain the behavior model for the schmutzdecke layer on the filter. The system dynamic approach focused on treatment scenarios that can determine the behavior of the slow sand filter system. Several factors were assessed, including temperature, turbidity, nutrient concentration, algal concentration, bacteria and dissolved oxygen. Model simulation results show that the comparison of C: N: P values affected the performance of the schmutzdecke layer in removing total coli. The slow sand filter unit was capable of producing treated water with a total amount of coli equal to 0 on the C: N: P values of 85: 5.59: 1.25, respectively, and a 9 cm geotextile thickness.
    Matched MeSH terms: Temperature
  11. Chow CH, Cheah W, Tai JH, Liu SF
    Sci Rep, 2019 10 29;9(1):15550.
    PMID: 31664110 DOI: 10.1038/s41598-019-51989-x
    In summer 2010, a massive bloom appeared in the middle (16-25°N, 160-200°E) of the North Pacific Subtropical Gyre (NPSG) creating a spectacular oasis in the middle of the largest oceanic desert on Earth. Peaked in June 2010 covering over two million km2 in space, this phytoplankton bloom is the largest ever recorded by ocean color satellites in the NPSG over the period from 1997 to 2013. The initiation and mechanisms sustaining the massive bloom were due to atmospheric and oceanic anomalies. Over the north (25-30°N) of the bloom, strong anticyclonic winds warmed sea surface temperature (SST) via Ekman convergence. Subsequently, anomalous westward ocean currents were generated by SST meridional gradients between 19°N and 25°N, producing strong velocity shear that caused large number of mesoscale (100-km in order) cyclonic eddies in the bloom region. The ratio of cyclonic to anticyclonic eddies of 2.7 in summer 2010 is the highest over the 16-year study period. As a result of the large eddy-number differences, eddy-eddy interactions were strong and induced submesoscale (smaller than 100 km) vertical pumping as observed in the in-situ ocean profiles. The signature of vertical pumping was also presented in the in-situ measurements of chlorophyll and nutrients, which show higher concentrations in 2010 than other years.
    Matched MeSH terms: Temperature
  12. Majdi HS, Saud AN, Saud SN
    Materials (Basel), 2019 May 29;12(11).
    PMID: 31146451 DOI: 10.3390/ma12111752
    Porous γ-alumina is widely used as a catalyst carrier due to its chemical properties. These properties are strongly correlated with the physical properties of the material, such as porosity, density, shrinkage, and surface area. This study presents a technique that is less time consuming than other techniques to predict the values of the above-mentioned physical properties of porous γ-alumina via an artificial neural network (ANN) numerical model. The experimental data that was implemented was determined based on 30 samples that varied in terms of sintering temperature, yeast concentration, and socking time. Of the 30 experimental samples, 25 samples were used for training purposes, while the other five samples were used for the execution of the experimental procedure. The results showed that the prediction and experimental data were in good agreement, and it was concluded that the proposed model is proficient at providing high accuracy estimation data derived from any complex analytical equation.
    Matched MeSH terms: Temperature
  13. Wan Jusoh WZA, Abdul Rahman S, Ahmad AL, Mohd Mokhtar N
    Data Brief, 2019 Jun;24:103910.
    PMID: 31193576 DOI: 10.1016/j.dib.2019.103910
    This paper focus to examine the best molecular interaction between Polyamide Thin Film Composite (PA TFC) layers with different properties of the support membrane. The support membrane of Nylon 66 (N66) and Polyvinylidene fluoride (PVDF) was chosen to represent the hydrophilic and hydrophobic model respectively in the Molecular Dynamic (MD) simulation. The Condensed-Phase Optimized Molecular Potential for Atomistic Simulation Studies (COMPASS) force field was used with the total simulation runs were set 1000 picoseconds run production ensembles. The temperature and pressure set for both ensembles were 298 K and 1 atm respectively. The validity of our model densities data was check and calculated where the deviation must be less than 6%. The comparison between hydrophobic and hydrophilic of the support membrane data was examined by the distance and magnitude of intensity of the Radial Distribution Function (RDF's) trends.
    Matched MeSH terms: Temperature
  14. Mustafa NS, Yahya MS, Sazelee N, Ali NA, Ismail M
    ACS Omega, 2018 Dec 31;3(12):17100-17107.
    PMID: 31458330 DOI: 10.1021/acsomega.8b02281
    The K2NiF6 catalytic effect on the NaAlH4 dehydrogenation properties was studied in this work. The desorption temperature was studied using temperature-programmed desorption and exhibited a lower onset hydrogen release after doped with different wt % of K2NiF6 (5, 10, 15 and 20 wt %). It was found that the NaAlH4 doped with 5 wt % K2NiF6 showed the optimal value that can reduce the onset desorption temperature of about 160 °C compared to 190 °C for the milled NaAlH4. The NaAlH4 + 5 wt % K2NiF6 sample showed faster desorption kinetics where 1.5 wt % of hydrogen was released in 30 min at 150 °C. In contrast, the milled NaAlH4 only released about 0.2 wt % within the same time and temperature. From the Kissinger analysis, the apparent activation energy was 114.7 kJ/mol for the milled NaAlH4 and 89.9 kJ/mol for the NaAlH4-doped 5 wt % K2NiF6, indicating that the addition of K2NiF6 reduced the activation energy for hydrogen desorption of NaAlH4. It is deduced that the new phases of AlNi, NaF, and KH that were formed in situ during the dehydrogenation process are the key factors for the improvement of dehydrogenation properties of NaAlH4.
    Matched MeSH terms: Temperature
  15. Tuan Mohamood NFA, Zainuddin N, Ahmad Ayob M, Tan SW
    Chem Cent J, 2018 Dec 06;12(1):133.
    PMID: 30523481 DOI: 10.1186/s13065-018-0500-8
    In this study, sago starch was modified in order to enhance its physicochemical properties. Carboxymethylation was used to introduce a carboxymethyl group into a starch compound. The carboxymethyl sago starch (CMSS) was used to prepare smart hydrogel by adding acetic acid into the CMSS powder as the crosslinking agent. The degree of substitution of the CMSS obtained was 0.6410. The optimization was based on the gel content and degree of swelling of the hydrogel. In this research, four parameters were studied in order to optimize the formation of CMSS-acid hydrogel. The parameters were; CMSS concentration, acetic acid concentration, reaction time and reaction temperature. From the data analyzed, 76.69% of optimum gel content was obtained with 33.77 g/g of degree of swelling. Other than that, the swelling properties of CMSS-acid hydrogel in different media such as salt solution, different pH of phosphate buffer saline solution as well as acidic and alkaline solution were also investigated. The results showed that the CMSS-acid hydrogel swelled in both alkaline and salt solution, while in acidic or low pH solution, it tended to shrink and deswell. The production of the hydrogel as a smart material offers a lot of auspicious benefits in the future especially related to swelling behaviour and properties of the hydrogel in different types of media.
    Matched MeSH terms: Temperature
  16. Hasnah Haron, Tasneem Shaari, Chan BK
    Sains Malaysiana, 2016;45:1329-1335.
    Soy-based products are one of famous raw ingredients used in the preparation of Asian cuisines. These soy-based products are good source of isoflavones. This study was carried out to observe the effects of different cooking methods on isoflavone content in soy-based products. A total of eight Malaysian dishes prepared using soy-based products with different cooking methods was selected as samples for this study. Daidzein and genestein contents in raw and cooked soy-based products were both quantified using high performance liquid chromatography (HPLC). The results showed that dishes containing tempe as ingredients had significantly higher (p<0.05) amount of isoflavone content, in both raw and cooked forms, as compared to those prepared from other types of soy-based products when based on dry and wet. In conclusion, the isoflavone content was significantly reduced (p<0.05) in some cooked soy-based products (tempe (TSS and ML), fu jook (ML) and firm tofu (FTC)) based on dry weight as compared with the raw ones. However, the correlations between isoflavone content with cooking methods, durations and temperatures were not significant (p>0.05) in this study.
    Matched MeSH terms: Temperature
  17. Siti Mariam Norrulashikin, Fadhilah Yusof, Ibrahim Lawal Kane
    Sains Malaysiana, 2018;47:409-417.
    The vector autoregressive (VAR) approach is useful in many situations involving model development for multivariables
    time series. VAR model was utilised in this study and applied in modelling and forecasting four meteorological variables.
    The variables are n rainfall data, humidity, wind speed and temperature. However, the model failed to address the
    heteroscedasticity problem found in the variables, as such, multivariate GARCH, namely, dynamic conditional correlation
    (DCC) was incorporated in the VAR model to confiscate the problem of heteroscedasticity. The results showed that the use
    of the VAR coupled with the recognition of time-varying variances DCC produced good forecasts over long forecasting
    horizons as compared with VAR model alone.
    Matched MeSH terms: Temperature
  18. Ikhwanuddin M, Abol-Munafi AB, Azra MN
    Data Brief, 2019 Aug;25:104196.
    PMID: 31321277 DOI: 10.1016/j.dib.2019.104196
    This data article includes raw and analyze data for molting duration and time of hardening of blue swimming crab, Portunus pelagicus instar at three different temperatures of 24 °C, 28 °C, and 32 °C. Two sets of experimental data are included: first, the recorded on time-lapse video of duration of successful molted crabs (from emergence of swimming legs to chelae); and second, the time interval of shell hardening up to before molting occurred. Shell hardening were calculated in 1 h interval with a unit of x hour molting crab-1, meanwhile the molting duration of the crabs were calculated in x second molting crab-1. Video files were then analyzed using the latest version of Solomon Coder software developed by A. Peter. Relationship between culture temperature and the time of molting and carapace hardening are also included in this article. The dataset is made publicly available to enable critical or extended analyzes.
    Matched MeSH terms: Temperature
  19. Dzulkharnien NSF, Karim MR, Zahid NI, Rahman NMMA, Abdullah I, Salleh NM
    J Fluoresc, 2019 Jul;29(4):1049-1056.
    PMID: 31338718 DOI: 10.1007/s10895-019-02418-9
    The optical properties of a series of side chain liquid crystalline polymers (P1-P3) containing azo-benzothiazole mesogen with different terminal substituents (-H, -CH3 and -OCH2CH3) in four organic solvents of varying polarity have been investigated by absorption and fluorescence spectral analysis. Solvatochromic studies of P1-P3 did not show any regular variation on the absorption and emission intensities with changing the polarity of solvent. Theoretical studies were performed based on different solvent correlation methods such as Dimroth-Reichardt and Kamlet-Taft methods to investigate the solute-solvent interactions. Both absorption and emission maxima of investigated polymers were bathochromically shifted with the replacement of sixth position hydrogen atom by electron donating groups in benzothiazole moiety. The emission intensities of the studied polymers showed decreasing trend with increasing temperature.
    Matched MeSH terms: Temperature
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