Pub Date : 2021-12-02DOI: 10.30880/jst.2021.13.02.001
S. Soloi, Azrad Usman
The paper presents some results on the ability of palm oil polyol to replace the petroleum-based polyol in polyurethane (PU) synthesis. In this study, palm oil polyol with amine functionality with hydroxyl value (OH value) between 240 -253 mg KOH/g was used as the polyol component to replace the conventional petroleum-based polyol. Four different formulationsof polyurethane coating have been prepared using pre-polymer process namely PU1, PU2, PU3 and PU4 with the polyol to isophorone diisocyanate ratio (OH:NCO) of 1:0.6 and 1:0.5 and acetone within 25-50 wt %. PU1 (1:0.6) and PU2(1:0.5) result in brittle film, while PU3 (1:0.6) and PU4 (1:05) has a soft and flexiblefilm with better transparency. This finding establishes that the acetone content effect the final properties of the polyurethane formed. The polymerization reaction was monitored using thefourier transform infra-red spectroscopy and it was found that the peak correspondsto NH (3302 cm-1), CO (1627 cm-1) and CN (1543 cm-1) stretching of urethane linkage appearingin all the PU films. The water uptake test was done on the films and it was found that the percentage of water uptake is less than 5% within 24 hours of immersion.The surface morphology of the PU films shows thathomogeneitywas achieved in 1:0.6 of OH:NCO ratio with 25 wt% of acetone. The PU films havethe potential to be developed for water resistant coating.
{"title":"Palm Oil Based Water-Resistant Coating using Pre-Polymer Method","authors":"S. Soloi, Azrad Usman","doi":"10.30880/jst.2021.13.02.001","DOIUrl":"https://doi.org/10.30880/jst.2021.13.02.001","url":null,"abstract":"The paper presents some results on the ability of palm oil polyol to replace the petroleum-based polyol in polyurethane (PU) synthesis. In this study, palm oil polyol with amine functionality with hydroxyl value (OH value) between 240 -253 mg KOH/g was used as the polyol component to replace the conventional petroleum-based polyol. Four different formulationsof polyurethane coating have been prepared using pre-polymer process namely PU1, PU2, PU3 and PU4 with the polyol to isophorone diisocyanate ratio (OH:NCO) of 1:0.6 and 1:0.5 and acetone within 25-50 wt %. PU1 (1:0.6) and PU2(1:0.5) result in brittle film, while PU3 (1:0.6) and PU4 (1:05) has a soft and flexiblefilm with better transparency. This finding establishes that the acetone content effect the final properties of the polyurethane formed. The polymerization reaction was monitored using thefourier transform infra-red spectroscopy and it was found that the peak correspondsto NH (3302 cm-1), CO (1627 cm-1) and CN (1543 cm-1) stretching of urethane linkage appearingin all the PU films. The water uptake test was done on the films and it was found that the percentage of water uptake is less than 5% within 24 hours of immersion.The surface morphology of the PU films shows thathomogeneitywas achieved in 1:0.6 of OH:NCO ratio with 25 wt% of acetone. The PU films havethe potential to be developed for water resistant coating.","PeriodicalId":21913,"journal":{"name":"Songklanakarin Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79241123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-02DOI: 10.30880/jst.2021.13.02.003
Muhammad Imran Jaafar, Hossameldin M.M.M. Rabah, N. D. Nordin, A. Muthalif, A. N. Wahid
Energy harvesting devices are needed as an alternative to batteries as it is costly to power up wireless sensor network. However, the power generated and operating bandwidth for the typical energy harvester are still compromised. Therefore, in this work, the use of permanent magnet in Piezoelectric Energy Harvester (PEH) is proposed to increase the operating bandwidth. A simulation study was conducted using COMSOL Multiphysics software to observe the effect of mechanical tuning using magnet on the voltage produced. It shows that PEH with oscillating magnetic field is capable of reaching generated peak power of 0.775 mW and increase the operating bandwidth by 10%. Experimental setup was also fabricated to further validate the observation at different polarities and varying distances with permanent magnets. It is observed that while the peak power achieved in the attractive mode is smaller as compared to its counterpart, however, its bandwidth is larger.
{"title":"Voltage Generation in Piezoelectric Energy Harvesting with Magnet: FEA Simulation and Experimental Analysis","authors":"Muhammad Imran Jaafar, Hossameldin M.M.M. Rabah, N. D. Nordin, A. Muthalif, A. N. Wahid","doi":"10.30880/jst.2021.13.02.003","DOIUrl":"https://doi.org/10.30880/jst.2021.13.02.003","url":null,"abstract":"Energy harvesting devices are needed as an alternative to batteries as it is costly to power up wireless sensor network. However, the power generated and operating bandwidth for the typical energy harvester are still compromised. Therefore, in this work, the use of permanent magnet in Piezoelectric Energy Harvester (PEH) is proposed to increase the operating bandwidth. A simulation study was conducted using COMSOL Multiphysics software to observe the effect of mechanical tuning using magnet on the voltage produced. It shows that PEH with oscillating magnetic field is capable of reaching generated peak power of 0.775 mW and increase the operating bandwidth by 10%. Experimental setup was also fabricated to further validate the observation at different polarities and varying distances with permanent magnets. It is observed that while the peak power achieved in the attractive mode is smaller as compared to its counterpart, however, its bandwidth is larger.","PeriodicalId":21913,"journal":{"name":"Songklanakarin Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72459136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-02DOI: 10.30880/jst.2021.13.02.004
Wahidah Mohd Zain, Sufy Rabea Adawiya Idris, Mohd Faizal Mohd Ramsi, S. K. Nordin
After 20 years of establishment, the number of Universiti Teknologi MARA (UiTM) campuses across Malaysia has reached 35 in number. Although the campuses' development of campuses had somehow made the location widely known as one of the education hubs in Malaysia, there exist doubts about the extent of development of each campus in an area that can benefit the locality. The focus of this paper is assessing the land-use changes due to the development of three campuses of UiTM Negeri Sembilan from 1999 to 2019. This study uses satellite images, GIS technology, and web-based maps applications as data collection tools. Two aspects were assessed, viz; Land-use Land Cover (LULC) and change detection. The result shows an increasing pattern of LULC. Also, the land conversion occurred more in Seremban compared to UiTM Kuala Pilah and Rembau. Change detection analysis in this paper reveals that the green area is declining via a higher percentage of deforestation and urbanization. Land-use change detection technique is confirmed as an effective method for measuring and evaluating urban development operations and their effect. Therefore, this research emphasized that LULC and change detection analysis results beneficial in identifying the development impact and important to facilitate strategize steps and policies in averting the affected areas from pollution and deforestation side effects. This study also suggests that such research extended to more Institutes of Higher Learning in Malaysia and South East Asia. The findings should be valuable to researchers, town planners, university administrators, and local authorities alike and contribute towards sustainable land-use planning and management in Malaysiain the near future.
经过20年的发展，马来西亚理工大学(Universiti technologii MARA)的校园数量已达到35个。虽然校园的发展在某种程度上使该地区成为马来西亚广为人知的教育中心之一，但人们对每个校园在一个地区的发展程度是否能使当地受益存在疑问。本文的重点是评估1999年至2019年因南森美兰理工大学三个校区的发展而导致的土地利用变化。本研究使用卫星图像、地理信息系统技术和基于网络的地图应用程序作为数据收集工具。评估了两个方面，即;土地利用-土地覆盖(LULC)及其变化检测。结果表明，LULC呈增加趋势。此外，与吉隆坡和伦堡相比，雪兰邦的土地转换发生得更多。本文的变化检测分析表明，由于森林砍伐和城市化的比例较高，绿地面积正在下降。土地利用变化检测技术是衡量和评价城市发展运作及其效果的有效方法。因此，本研究强调，LULC和变化检测分析结果有助于识别发展影响，并有助于制定策略步骤和政策，以避免受影响地区受到污染和森林砍伐的副作用。本研究亦建议将此研究推广至马来西亚及东南亚的更多高等学府。研究结果对研究人员、城市规划者、大学管理人员和地方当局都有价值，并有助于在不久的将来实现马来西亚的可持续土地利用规划和管理。
{"title":"Analysing Land-use Land Cover (LULC) and Development Change in Nearby University Campuses’ Area: A Case of Universiti Teknologi MARA Negeri Sembilan, Malaysia","authors":"Wahidah Mohd Zain, Sufy Rabea Adawiya Idris, Mohd Faizal Mohd Ramsi, S. K. Nordin","doi":"10.30880/jst.2021.13.02.004","DOIUrl":"https://doi.org/10.30880/jst.2021.13.02.004","url":null,"abstract":"After 20 years of establishment, the number of Universiti Teknologi MARA (UiTM) campuses across Malaysia has reached 35 in number. Although the campuses' development of campuses had somehow made the location widely known as one of the education hubs in Malaysia, there exist doubts about the extent of development of each campus in an area that can benefit the locality. The focus of this paper is assessing the land-use changes due to the development of three campuses of UiTM Negeri Sembilan from 1999 to 2019. This study uses satellite images, GIS technology, and web-based maps applications as data collection tools. Two aspects were assessed, viz; Land-use Land Cover (LULC) and change detection. The result shows an increasing pattern of LULC. Also, the land conversion occurred more in Seremban compared to UiTM Kuala Pilah and Rembau. Change detection analysis in this paper reveals that the green area is declining via a higher percentage of deforestation and urbanization. Land-use change detection technique is confirmed as an effective method for measuring and evaluating urban development operations and their effect. Therefore, this research emphasized that LULC and change detection analysis results beneficial in identifying the development impact and important to facilitate strategize steps and policies in averting the affected areas from pollution and deforestation side effects. This study also suggests that such research extended to more Institutes of Higher Learning in Malaysia and South East Asia. The findings should be valuable to researchers, town planners, university administrators, and local authorities alike and contribute towards sustainable land-use planning and management in Malaysiain the near future.","PeriodicalId":21913,"journal":{"name":"Songklanakarin Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90645786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-02DOI: 10.30880/jst.2021.13.02.002
Dauda Taofik O, Adetayo Adewale O
This work was accomplished to assess the rainfall probability density function (pdf) of Katsina State and adopt the most parsimonious density function using 2003 –2018 rainfall data from the Nigeria Institute of Meteorological Services. The data were subjected to cleaning, descriptive statistics and investigation of five distribution functions (General pareto, general extreme value, Gumbel maximum, Uniform and Normal distribution) through parameterizations. The results intimated that Daura experienced the highest mean annual rainfall ranging between 75.667 mm for 2003 and 82.417 mm for 2018. Both Dutsin-Ma and Safana local Government returned the least mean annual rainfall alternately and it ranged between 57.500 mm (2009 rainfall for Dutsin-Ma) and 67.167 mm for 2018 mean annual rainfall of Safana. The order of performance of the five (5) prominent pdf in each of the sites differs but the Generalized Pareto distribution (GPD) ranked highest across all the sites. The distribution characteristics for the GPD (the most parsimonious of the pdf) are, mean = 61.15098 (Duara), 58.93371 (Dutsinma) and 79.20851 (Safana) and variance of 9212.603 (Duara), 6709.908 (Dutsinma) and 6687.102 (Safana). The examination of the visual analysis of the residuals of the mean annual rainfall indicated that only the mean rainfall for Dutsin-Ma gave the most precise parameter estimates.
{"title":"On the Generalized Pareto Probability Density Function of the Mean Annual Rainfall of Katsina State","authors":"Dauda Taofik O, Adetayo Adewale O","doi":"10.30880/jst.2021.13.02.002","DOIUrl":"https://doi.org/10.30880/jst.2021.13.02.002","url":null,"abstract":"This work was accomplished to assess the rainfall probability density function (pdf) of Katsina State and adopt the most parsimonious density function using 2003 –2018 rainfall data from the Nigeria Institute of Meteorological Services. The data were subjected to cleaning, descriptive statistics and investigation of five distribution functions (General pareto, general extreme value, Gumbel maximum, Uniform and Normal distribution) through parameterizations. The results intimated that Daura experienced the highest mean annual rainfall ranging between 75.667 mm for 2003 and 82.417 mm for 2018. Both Dutsin-Ma and Safana local Government returned the least mean annual rainfall alternately and it ranged between 57.500 mm (2009 rainfall for Dutsin-Ma) and 67.167 mm for 2018 mean annual rainfall of Safana. The order of performance of the five (5) prominent pdf in each of the sites differs but the Generalized Pareto distribution (GPD) ranked highest across all the sites. The distribution characteristics for the GPD (the most parsimonious of the pdf) are, mean = 61.15098 (Duara), 58.93371 (Dutsinma) and 79.20851 (Safana) and variance of 9212.603 (Duara), 6709.908 (Dutsinma) and 6687.102 (Safana). The examination of the visual analysis of the residuals of the mean annual rainfall indicated that only the mean rainfall for Dutsin-Ma gave the most precise parameter estimates.","PeriodicalId":21913,"journal":{"name":"Songklanakarin Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82478177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-02DOI: 10.30880/jst.2021.13.02.007
P. Chhabra
This article gives a really vital and curiously inequality on Jain-Saraswat’s functional discrimination in terms of the Hellinger discrimination and Bhattacharya discrimination by taking into thoughtL-Lipschitzian functions. Encourage, we outlined a few vital results by utilizing the inferred inequality with numerical confirmation.
{"title":"New Inequality for L-Lipschitzian Functions and Applications","authors":"P. Chhabra","doi":"10.30880/jst.2021.13.02.007","DOIUrl":"https://doi.org/10.30880/jst.2021.13.02.007","url":null,"abstract":"This article gives a really vital and curiously inequality on Jain-Saraswat’s functional discrimination in terms of the Hellinger discrimination and Bhattacharya discrimination by taking into thoughtL-Lipschitzian functions. Encourage, we outlined a few vital results by utilizing the inferred inequality with numerical confirmation.","PeriodicalId":21913,"journal":{"name":"Songklanakarin Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80929869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-02DOI: 10.30880/jst.2021.13.02.005
M. Khabiri, Zohreh Ghafoori Fard
Mathematical optimization, also called mathematical programming, is the process by which the best answer (according to a set of criteria) is selected from a set of possible answers to a particular problem. Today, optimization problems are used in all quantitative fields such as computer science, engineering, operations research, economics, and more; one of the engineering disciplines in which optimization is very important is road and transportation engineering. Road repair is one of the most important componentsof pavement management that requires regular road inspection by road specialists. One of the most important measures to prevent failure is maintenance inspection; Assessment of the condition of road surfaces to ensure their performance, while the road still provides maximum safety for existing traffic, should be done to ensure timely and effective repair and reconstruction operations. But exactly when these inspections should take place and when they are effective is an issue that is addressed in this study. The aim of this study is to optimize the frequency of maintenance inspections for a high-traffic suburban road by optimizing the frequency of inspections with a certain degree of reliability; so, the breakage function was considered as a pavement condition index (PCI). The results show that in order to pave the suburban road with high traffic in order to perform the desired pavement with 95% reliability, 218 inspections should be carried out annually (on average once every two days).
{"title":"Application of Mathematical Models for Optimizing Inspection Frequency in Maintenance and Management of Pavement","authors":"M. Khabiri, Zohreh Ghafoori Fard","doi":"10.30880/jst.2021.13.02.005","DOIUrl":"https://doi.org/10.30880/jst.2021.13.02.005","url":null,"abstract":"Mathematical optimization, also called mathematical programming, is the process by which the best answer (according to a set of criteria) is selected from a set of possible answers to a particular problem. Today, optimization problems are used in all quantitative fields such as computer science, engineering, operations research, economics, and more; one of the engineering disciplines in which optimization is very important is road and transportation engineering. Road repair is one of the most important componentsof pavement management that requires regular road inspection by road specialists. One of the most important measures to prevent failure is maintenance inspection; Assessment of the condition of road surfaces to ensure their performance, while the road still provides maximum safety for existing traffic, should be done to ensure timely and effective repair and reconstruction operations. But exactly when these inspections should take place and when they are effective is an issue that is addressed in this study. The aim of this study is to optimize the frequency of maintenance inspections for a high-traffic suburban road by optimizing the frequency of inspections with a certain degree of reliability; so, the breakage function was considered as a pavement condition index (PCI). The results show that in order to pave the suburban road with high traffic in order to perform the desired pavement with 95% reliability, 218 inspections should be carried out annually (on average once every two days).","PeriodicalId":21913,"journal":{"name":"Songklanakarin Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81940796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-25DOI: 10.30880/JST.2021.13.01.004
J. Nzumile
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.
{"title":"A Comparison of Beat Frequency Estimation Methods for Large Ring Laser","authors":"J. Nzumile","doi":"10.30880/JST.2021.13.01.004","DOIUrl":"https://doi.org/10.30880/JST.2021.13.01.004","url":null,"abstract":"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.","PeriodicalId":21913,"journal":{"name":"Songklanakarin Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72718526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-25DOI: 10.30880/JST.2021.13.01.003
Sunusi A. Zubair, U. Gaya
Granular activated carbons have been important adsorbents for the decontamination of aqueous environmental contaminants. Acanthospermum hispidum 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 Accanthospermum hispindum (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 < AC-T < NaOH-T.
{"title":"Adsorption of Aqueous Using Granular Adsorbents from Accanthospermum hispendum DC","authors":"Sunusi A. Zubair, U. Gaya","doi":"10.30880/JST.2021.13.01.003","DOIUrl":"https://doi.org/10.30880/JST.2021.13.01.003","url":null,"abstract":"Granular activated carbons have been important adsorbents for the decontamination of aqueous environmental contaminants. Acanthospermum hispidum 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 Accanthospermum hispindum (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 < AC-T < NaOH-T.","PeriodicalId":21913,"journal":{"name":"Songklanakarin Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83441693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-25DOI: 10.30880/JST.2021.13.01.006
A. Ayuba, M. Abubakar
The present work describes the computational methods for 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 Guirea senegalensis. Quantum chemical calculations including EHOMO, ELUMO, energy gap (ΔE), electronegativity (χ), global hardness (η) and fraction of electrons transfer from the inhibitor molecule to the aluminium surface (ΔN) were calculated. 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(l10) 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(110) 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.
{"title":"Computational Study for Molecular Properties of Some of the Isolated Chemicals from Leaves Extract of Guiera Senegalensis as Aluminium Corrosion Inhibitor","authors":"A. Ayuba, M. Abubakar","doi":"10.30880/JST.2021.13.01.006","DOIUrl":"https://doi.org/10.30880/JST.2021.13.01.006","url":null,"abstract":"The present work describes the computational methods for 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 Guirea senegalensis. Quantum chemical calculations including EHOMO, ELUMO, energy gap (ΔE), electronegativity (χ), global hardness (η) and fraction of electrons transfer from the inhibitor molecule to the aluminium surface (ΔN) were calculated. 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(l10) 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(110) 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.","PeriodicalId":21913,"journal":{"name":"Songklanakarin Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76934733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-18DOI: 10.30880/JST.2021.13.01.001
R. Yahyazadeh, Z. Hashempour
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. 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.
{"title":"Effect of Hydrostatic Pressure and Temperature on Quantum Confinement of AlGaN/GaN HEMTs","authors":"R. Yahyazadeh, Z. Hashempour","doi":"10.30880/JST.2021.13.01.001","DOIUrl":"https://doi.org/10.30880/JST.2021.13.01.001","url":null,"abstract":"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. 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.","PeriodicalId":21913,"journal":{"name":"Songklanakarin Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83681499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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