https://publisher.uthm.edu.my/ojs/index.php/JST/issue/feed Journal of Science and Technology 2021-07-15T12:39:27+08:00 Ahmad Hadi Ali jst@uthm.edu.my Open Journal Systems <p>Journal of Science and Technology (JST) aim to publish original and high quality articles (be it in theoretical or applied perspectives) on all aspects of science and technology. This peer reviews journal seek to publish TWO (2) issues annually.</p> <p>JST is devoted in providing a platform for the publication of full-length articles focusing (and not limited) to research areas as listed below:</p> <p>Physics, Chemistry, Mathematics, Statistic, Biodiversity, Food Science and Technology as well as Engineering and Education Science.</p> https://publisher.uthm.edu.my/ojs/index.php/JST/article/view/7617 Effect of Hydrostatic Pressure and Temperature on Quantum Confinement of AlGaN/GaN HEMTs 2021-04-18T16:13:55+08:00 Rajab Yahyazadeh r.yahyazadeh@iaurmia.ac.ir Zahra Hashempour Rajab.Yahyazadeh@iaukhoy.ac.ir <p>In this paper, an analytical model for quantum confinement electron density in two-dimensional quantum well, has been investigated. In order to obtain the exact AlGaN/GaN HEMTs parameters such as electron density, the wave function, band gap, polarization charge, effective mass and dielectric constant, the hydrostatic pressure and temperature effects are taken into account. It has been found that the electron density decreases with increasing temperature and increases with increasing hydrostatic pressure. With increasing hydrostatic pressure, the effective mass decreases and the quantum confinement electrons are increased in the quantum well. Also with increasing hydrostatic pressure, the height of wave functions increase and decreases electron wave functions to penetrate the quantum barrier but increasing the temperature behaves the opposite of increasing the pressure.&nbsp;&nbsp; However, with increasing temperature, the effective mass is increased and the quantum confinement electrons are reduced. The calculated results for electron density are in good agreement with existing experimental data.</p> 2021-04-18T15:39:16+08:00 Copyright (c) 2021 Journal of Science and Technology https://publisher.uthm.edu.my/ojs/index.php/JST/article/view/7359 Effects of an Acute Bout of Exercise on Salivary Lactoferrin Responses among Smokers and Non-Smokers 2021-04-18T16:13:56+08:00 Halimatun Saadiah Ahmad sofyatun9494@gmail.com Ayu Suzailiana Muhamad ayu_suzailiana@usm.my <p>Smoking can weaken immune function as reported in previous studies. However, benefits of exercise in reducing negative effects of smoking on salivary lactoferrin responses is scarce to date. Hence, the purpose of this study is to determine the effects of an acute bout of exercise on salivary lactoferrin responses among smokers and non-smokers. Eighteen sedentary men were recruited; nine smokers (age = 22.4 ± 1.4 years; BMI = 22.1 ± 1.1 kg/m2) and nine non-smokers (age = 22.1 ± 0.7 years old; BMI = 22.5 ± 1.9 kg/m2). In this study, participants cycled at an intensity of 60% maximum heart rate for 60 minutes. Participants were given cool water as much as 3 ml/kg body weight at minutes 20 and 40 during the exercise session. Participants’ body weight and saliva samples were collected at pre and post-exercise. Heart rate and rate of perceived exertion (RPE) were recorded at pre, during and post-exercise. Mixed ANOVA was used to measure significant differences between groups and within group. The results showed that saliva flow rate, lactoferrin concentration and lactoferrin secretion rate were not significantly different (p&gt;0.05) between smokers and non-smokers groups and also between pre and post-exercise within each group. Heart rate and RPE showed significant increased (p&lt;0.05) during the exercise session in both groups. As a conclusion, acute bout of exercised does not affect salivary lactoferrin responses among sedentary smokers and non-smokers men.</p> 2021-04-18T16:09:43+08:00 Copyright (c) 2021 Journal of Science and Technology https://publisher.uthm.edu.my/ojs/index.php/JST/article/view/7611 Adsorption of Aqueous Using Granular Adsorbents from Accanthospermum hispendum DC 2021-05-25T10:08:38+08:00 Umar Ibrahim Gaya uigaya.chm@buk.edu.ng Sunusi A. Zubair sanusiabdullahizubairu@gmail.com <p>Granular activated carbons have been important adsorbents for the decontamination of aqueous environmental contaminants. <em>Acanthospermum hispidum </em>weed represents a ready available source of low-cost adsorbents in sub-Saharan Africa that has barely been paid attention. The effects of pH, contact time, concentration, adsorbent dosage, particle size and temperature on the adsorptive removal of Pb (II) from aqueous solutions over activated carbon granules from the thorns of <em>Accanthospermum hispindum </em>(AC-T) were for the first time investigated and compared with those of the leaves (L), the sodium hydroxide modified thorns (NaOH-T) and regular thorns (T) of this plant. These adsorbents were characterised by the surface charge analysis, scanning electron microscopy (SEM) and the Attenuated Total Reflectance Fourier Transform infrared (ATR FTIR) spectroscopy. The SEM revealed a wafer-like appearance for the AC-T with a large distribution of open pores. The adsorption data of lead uptake onto the adsorbents were examined using two pseudo-order kinetic schemes and three isotherm models. To fully understand the adsorption capacities of the adsorbents, batch desorption recoveries were studied. The FTIR depicted the various functionalities responsible for the adsorption. Adsorption over AC-T was found to agree with pseudo second-order kinetic scheme, the Langmuir and Freundlich isotherm. This material exhibited the highest adsorption capacity. The order of reusability of the adsorbents is T &lt; AC-T &lt; NaOH-T.</p> 2021-05-25T10:08:38+08:00 Copyright (c) 2021 Journal of Science and Technology https://publisher.uthm.edu.my/ojs/index.php/JST/article/view/7473 A Comparison of Beat Frequency Estimation Methods for Large Ring Laser 2021-05-25T10:05:27+08:00 Jailos Mrisho Nzumile mrishojailos@ymail.com <p>Autoregressive (AR2) technique has always been used to estimate frequency of the output signal from Large ring laser. However, the acquisition rate is not at near real time which is the requirement and noise level still challenge the process resulting to errors in the final estimation. A research was done to compare the Autoregressive (AR2) with the counterparts such as Pisarenko, Quinn, Hilbert and Phase looking for a better technique that will estimate the frequency at near real time to minimize errors. Secondary data from G and C – II ring laser were used during the comparison between the techniques and Autoregressive (AR2). Results shows that, the output characteristics from the counterpart does not depict the oscillations of the Earth rotation as expected contrast to that of Autoregressive (AR2) which does. Moreover, there were much deviation from the expected true value for the techniques contrast to that of AR2 which is very minimum. On the other hand, when the C – II data were used, it was observed that both techniques resemble on their output characteristics though AR2 was still better in the acquisition rate expect for Hilbert transform which does not resemble with others. Following the scope of this paper, Autoregressive (AR2) technique still emerge as a favorite frequency estimation technique contrast to the four counterparts due to its robustness, high acquisition rate as well as low noise level.</p> 2021-05-25T10:05:26+08:00 Copyright (c) 2021 Journal of Science and Technology https://publisher.uthm.edu.my/ojs/index.php/JST/article/view/8432 Characterization of Amino-Functionalized Ferromagnetic Nanoparticles with Glutaraldehyde Cross-linking 2021-05-25T10:30:44+08:00 Jaravee Sukprasert sjaravee@gmail.com Kanjana Thumanu kanjanat@srli.or.th Isaratat Phung-on isratat.phu@kmutt.ac.th Chalermkiat Jirarungsatean chalermkiat.jir@kmutt.ac.th Peerapon Chaisalee Peerapon_Chaisalee@hotmail.com Pravate Tuitemwong pravate.tui@kmutt.ac.th Kooranee Tuitemwong fscikrt@ku.ac.th <p>Characterization of amino-functionalised magnetic nanoparticles (FMNs) modified surfaces with glutaraldehyde cross linker, which enables the attachment to a specific antibody against Salmonella was examined using FTIR spectroscopy. The magnetism property of the particles before and after attachment to the target cells was studied. Synchrotron FTIR spectroscopy technique was employed to investigate the chemistry of the crosslinking reaction to amino-functionalized ferromagnetic nanoparticles. Results indicated that the bonding pattern imine bond (C=N) and amide bond (-CONH-) were detected. The finding indicated the attachment of aldehyde group (CHO) to amino region of the particle and the other free end to link to the antibodies against <em>Salmonella</em>.&nbsp; The bonding allowed the antibodies to bear reactive sites to catch the target <em>Salmonella</em> in food samples. The FMNs demonstrated hysteresis characteristics that could be changed due to cell attachment that caused reduction of loop coercive force (H). Results showed evidence of glutaraldehyde crosslinking that could be also used as quality control for immobilization of antibodies to the particles. Magnetism properties (the coercive force H) and FTIR characteristics could be further used for signal of attachment of cells to the FMNs as well.</p> 2021-05-25T10:29:50+08:00 Copyright (c) 2021 Journal of Science and Technology https://publisher.uthm.edu.my/ojs/index.php/JST/article/view/8255 A Theoretical Study on Isolated Compounds from the Leaves Extract of Guiera Senegalensis as Aluminium Corrosion Inhibitor 2021-05-25T10:56:09+08:00 A. M. Ayuba ayubaabdullahi@buk.edu.ng M. Abubakar ayubaabdullahi@buk.edu.ng <p>The present work describes using computational methods the corrosion inhibition of aluminium using three selected chemical constituents (5-methyldihydroflavasperone, 5-methylflavasperone and methoxylated naphthyl butanone) reportedly obtained from the leaves extract of <em>Guirea senegalensis. </em>Quantum chemical calculations including E<sub>HOMO</sub>, E<sub>LUMO</sub>, energy gap (ΔE), electronegativity (χ), global hardness (η) and fraction of electrons transfer from the inhibitor molecule to the aluminium surface (ΔN) were calculated.&nbsp; The local reactive sites through Fukui indices which explain the effect of structural features of these components in relation to electrophilic and nucleophilic point of attack were evaluated. The similarities in quantum chemical parameters for the compounds obtained revealed that the adsorption strengths of the molecules will be mostly determined by molecular size rather than electronic structure parameters. Fukui indices showed that the point of interaction of inhibitor molecule with the Al(1 1 0) surface were through aromatic carbon atom rich in pi-electrons and oxygen atom of the alkanone functional group in the inhibitor molecules. Molecular dynamics simulations describing the adsorption behavior of the inhibitor molecule on Al(1 1 0) surface through Forcite quench molecular dynamics were carried out. The compounds were found to all obey the mechanism of physical adsorption because of their relatively low adsorption energies.</p> 2021-05-25T10:50:09+08:00 Copyright (c) 2021 Journal of Science and Technology https://publisher.uthm.edu.my/ojs/index.php/JST/article/view/7589 Assessment of Natural Radionuclides and Some Toxic Metals in Vegetables Cultivated Around Ibese and Ewekoro Cement Industries in Ogun State, Southwest Nigeria 2021-07-15T12:39:27+08:00 Ademola Augustine Kolapo sirkay006@yahoo.com Adejumobi Caleb Adeniyi caadejumobi@yahoo.com <p style="text-align: justify;">Absorption of natural radionuclides and heavy metals (HM) contents from wastes is a possible way of soil contamination which subsequently adversely affects the plants cultivated in the area and human health when consumed. Therefore, this study aimed to measure NORMs and some toxic metals in five types of vegetable; <em>Telfairia occidentalis, Corchorus olitorius, Solanum Lycopersicum, Amaranthus hybridus, and, Talinum fruticosum</em> around two cement industries in Ogun state using Sodium Iodide detector and Atomic Absorption Spectrometer. The mean concentrations of radionuclide (<sup>226</sup>Ra, <sup>228</sup>Ra, and <sup>40</sup>K) in the samples were 21.31±2.40, 10.62±2.52 and 220.71±14.32, respectively in <em>Telfairia occidentalis</em> and lower in all other samples. The metals analyzed (Pb, Cd, Cu, Ni and Zn) have their average concentrations as 0.08, 0.18, 3.21, 0.45 and 2.15 mg kg<sup>-1</sup> respectively in <em>Telfairia occidentalis</em>; 0.11, 0.07, 4.29, 0.58 and 2.84 mg kg<sup>-1</sup> in <em>Corchorus olitorius</em>; 1.00, 0.18, 4.20, 0.34 and 3.60 mg kg<sup>-1</sup> in <em>Solanum Lycopersicum</em>. The hazard indices obtained were 1.47, 1.69, 2.21, 1.71 and, 1.29, respectively, meaning hazard is probable from consuming the vegetables. The committed doses (0.4 and 0.38 µSv y<sup>-1</sup>) and the cancer risks (0.41 ×10<sup>-6</sup> in Ibese and 0.37 × 10<sup>-6</sup>) estimated are well below the United Nation Scientific Committee on Energy and Atomic Research.</p> 2021-06-24T00:00:00+08:00 Copyright (c) 2021 Journal of Science and Technology