M. M. H. S. Buddin, Nur Athirah Azrai, Effi Aidur Roza Roseli, Farhana Wahet, A. Ahmad
of ions extraction using trioctylamine as in ABSTRACT: Simultaneous extraction and stripping of Cd(II) ions from aqueous solution by using bulk liquid membrane (BLM) was explored. This study was aimed to identify the conditions to achieve maximum Cd(II) ions removal and the reaction kinetics was thoroughly analysed. The membrane phase was made by using trioctylamine (TOA) and kerosene, as carrier and diluent, respectively. Meanwhile, the feed phase contained the targeted solute (CdCl 2 ) dissolved in a pH adjusted solution while ammonia was used as the stripping agent. To achieve maximum Cd(II) ions removal, the effect of carrier concentration, stirring speed as well as extraction time were studied. Experimental data obtained shows that 0.1 wt% TOA in kerosene, 400 rpm stirring speed and 4 h of extraction time resulted in highest removal of Cd(II) ions. Furthermore, it was identified that the extraction process across BLM prefers acidic condition (pH of 1). The capability of the system to extract Cd(II) ions from the feed phase was known by using dimensionless reduced concentration, R f where the maximum removal of Cd(II) ions achieved was 0.0193 at the mentioned conditions. The reaction kinetics were investigated to identify the reaction rate constants for extraction reaction (k 1 ) and stripping reaction (k 2 ). The value of k 1 and k 2 were found to be 0.94 h –1 and 2.45 h –1 , respectively.
摘要:研究了体积液膜法(BLM)同时萃取和剥离水溶液中的Cd(II)离子。本研究旨在确定最大限度去除Cd(II)离子的条件，并对反应动力学进行了全面分析。以三辛胺(TOA)为载体，以煤油为稀释液制备膜相。同时，进料相中含有目标溶质(CdCl 2)，溶解在pH调节的溶液中，氨作为汽提剂。为了最大限度地去除Cd(II)离子，研究了载体浓度、搅拌速度和萃取时间的影响。实验结果表明，当煤油中TOA浓度为0.1 wt%、搅拌转速为400 rpm、萃取时间为4 h时，Cd(II)离子去除率最高。此外，还确定了BLM的萃取过程更倾向于酸性条件(pH为1)。通过使用无因次还原浓度R f，系统从进料相中提取Cd(II)离子的能力已知，在上述条件下，Cd(II)离子的最大去除率为0.0193。研究了反应动力学，确定了萃取反应(k1)和溶出反应(k2)的反应速率常数。k1和k2值分别为0.94 h -1和2.45 h -1。
{"title":"Kinetic Study of Cd(II) Ions Extraction Using Trioctylamine as Carrier in Bulk\u0000 Liquid Membrane (BLM)","authors":"M. M. H. S. Buddin, Nur Athirah Azrai, Effi Aidur Roza Roseli, Farhana Wahet, A. Ahmad","doi":"10.21315/jps2019.30.2.9","DOIUrl":"https://doi.org/10.21315/jps2019.30.2.9","url":null,"abstract":"of ions extraction using trioctylamine as in ABSTRACT: Simultaneous extraction and stripping of Cd(II) ions from aqueous solution by using bulk liquid membrane (BLM) was explored. This study was aimed to identify the conditions to achieve maximum Cd(II) ions removal and the reaction kinetics was thoroughly analysed. The membrane phase was made by using trioctylamine (TOA) and kerosene, as carrier and diluent, respectively. Meanwhile, the feed phase contained the targeted solute (CdCl 2 ) dissolved in a pH adjusted solution while ammonia was used as the stripping agent. To achieve maximum Cd(II) ions removal, the effect of carrier concentration, stirring speed as well as extraction time were studied. Experimental data obtained shows that 0.1 wt% TOA in kerosene, 400 rpm stirring speed and 4 h of extraction time resulted in highest removal of Cd(II) ions. Furthermore, it was identified that the extraction process across BLM prefers acidic condition (pH of 1). The capability of the system to extract Cd(II) ions from the feed phase was known by using dimensionless reduced concentration, R f where the maximum removal of Cd(II) ions achieved was 0.0193 at the mentioned conditions. The reaction kinetics were investigated to identify the reaction rate constants for extraction reaction (k 1 ) and stripping reaction (k 2 ). The value of k 1 and k 2 were found to be 0.94 h –1 and 2.45 h –1 , respectively.","PeriodicalId":16757,"journal":{"name":"Journal of Physical Science","volume":"5 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2019-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90182324","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}
The emission of greenhouse gases (GHGs), especially carbon dioxide (CO2), has been rising indiscriminately causing serious global warming issues. Therefore, to prevent severe consequences of global warming, stern efforts need to be taken to minimise the global GHG emission. One of the most suitable approaches chosen for removal of CO2 is the gas separation membrane technology. The main objective of this work is to synthesise a membrane with good CO2 permeance and CO2/nitrogen (N2) selectivity that can be applied in the industry. Firstly, the cellulose acetate butyrate (CAB) polymer matrix of molecular weight (Mn) 65000 was used to synthesise the membranes with different solvent evaporation times (4 min, 5 min and 6 min) and different solvent exchange drying times (15 min, 30 min and 60 min). Since the performance of the obtained CAB membrane performance was still relatively low (CO2/N2 selectivity of 0.978 ± 0.011), the mixed matrix membranes (MMMs) were introduced. The MMM was fabricated by using 4 wt% of CAB polymer of molecular weight (Mn) 65000 and 0.1 wt% of functionalised multi-walled carbon nanotubes (MWCNTs-F). In addition, the effect of different MWCNT loadings (0.2 wt% to 1.2 wt%) and acetyl contents (12 wt%–15 wt% and 28 wt%–31 wt%) on CO2/N2 separation were also investigated. The results proved that the MMM prepared from the CAB polymer of Mn 65000 and 0.1 wt% of MWCNTs with higher acetyl content, i.e., from 28 wt% to 31 wt% had better performance in terms of CO2/N2 selectivity (2.887 ± 0.068).
{"title":"Functionalised Multi-walled Carbon Nanotubes/Cellulose Acetate Butyrate Mixed\u0000 Matrix Membrane for CO2/N2 Separation","authors":"S. Lee, J. Pang, Z. Jawad","doi":"10.21315/jps2019.30.2.7","DOIUrl":"https://doi.org/10.21315/jps2019.30.2.7","url":null,"abstract":"The emission of greenhouse gases (GHGs), especially carbon dioxide (CO2), has been rising indiscriminately causing serious global warming issues. Therefore, to prevent severe consequences of global warming, stern efforts need to be taken to minimise the global GHG emission. One of the most suitable approaches chosen for removal of CO2 is the gas separation membrane technology. The main objective of this work is to synthesise a membrane with good CO2 permeance and CO2/nitrogen (N2) selectivity that can be applied in the industry. Firstly, the cellulose acetate butyrate (CAB) polymer matrix of molecular weight (Mn) 65000 was used to synthesise the membranes with different solvent evaporation times (4 min, 5 min and 6 min) and different solvent exchange drying times (15 min, 30 min and 60 min). Since the performance of the obtained CAB membrane performance was still relatively low (CO2/N2 selectivity of 0.978 ± 0.011), the mixed matrix membranes (MMMs) were introduced. The MMM was fabricated by using 4 wt% of CAB polymer of molecular weight (Mn) 65000 and 0.1 wt% of functionalised multi-walled carbon nanotubes (MWCNTs-F). In addition, the effect of different MWCNT loadings (0.2 wt% to 1.2 wt%) and acetyl contents (12 wt%–15 wt% and 28 wt%–31 wt%) on CO2/N2 separation were also investigated. The results proved that the MMM prepared from the CAB polymer of Mn 65000 and 0.1 wt% of MWCNTs with higher acetyl content, i.e., from 28 wt% to 31 wt% had better performance in terms of CO2/N2 selectivity (2.887 ± 0.068).","PeriodicalId":16757,"journal":{"name":"Journal of Physical Science","volume":"44 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2019-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80952274","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}
Surface quantum wells are seeking considerable attention due to their asymmetrical nature of polarized interface and its consequences. Their results with and without external perturbations are expected to be remarkably different from their counterparts in symmetrical quantum wells. Effect of electric field on binding energies of light hole and heavy hole exciton in surface quantum well composed of vacuum/GaAs/Ga1xAlxAs are theoretically calculated as a function of well width and Al composition. Effect of image charges arising due to the mismatch of the dielectric constant at the vacuum/GaAs interface is considered. Stark shift and polarizability of exciton in this surface quantum well is also calculated for various strengths of electric field with different well width confinement as well as Al concentration. Our results show that: (1) exciton binding energy increases as the electric field applied along the growth axis increases; (2) stark shift in exciton energy decreases as electric field, Al composition and well width increase; and (3) polarizability of exciton decreases when the electric field increases, but increases when well width increases. Variation of our results with those for other symmetrical wells will provide a choice of the well for electric field applications.
{"title":"Polarizability of Exciton in Surface Quantum Well","authors":"A. Anitha, M. Arulmozhi","doi":"10.21315/JPS2019.30.1.4","DOIUrl":"https://doi.org/10.21315/JPS2019.30.1.4","url":null,"abstract":"Surface quantum wells are seeking considerable attention due to their asymmetrical nature of polarized interface and its consequences. Their results with and without external perturbations are expected to be remarkably different from their counterparts in symmetrical quantum wells. Effect of electric field on binding energies of light hole and heavy hole exciton in surface quantum well composed of vacuum/GaAs/Ga1xAlxAs are theoretically calculated as a function of well width and Al composition. Effect of image charges arising due to the mismatch of the dielectric constant at the vacuum/GaAs interface is considered. Stark shift and polarizability of exciton in this surface quantum well is also calculated for various strengths of electric field with different well width confinement as well as Al concentration. Our results show that: (1) exciton binding energy increases as the electric field applied along the growth axis increases; (2) stark shift in exciton energy decreases as electric field, Al composition and well width increase; and (3) polarizability of exciton decreases when the electric field increases, but increases when well width increases. Variation of our results with those for other symmetrical wells will provide a choice of the well for electric field applications.","PeriodicalId":16757,"journal":{"name":"Journal of Physical Science","volume":"7 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2019-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78972616","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 : 2019-05-15DOI: 10.21315/JPS2019.30.1.12
S. Anda, R. Saad, M. Saidin, F. Andika, S. Muhammad, R. Yusoh
Geophysical methods have been widely used in archaeological prospecting for decades. This is for the fact that the methods provide a great deal of information for archaeologist to determine buried evidences beneath the surface. Geophysical methods are also cost effective, covering much larger area at relatively lower costs, compared with the conventional archaeological probing techniques. The methods are also non-destructive and non-invasive, keeping archaeological sites entirely undisturbed after survey. Several geophysical methods including resistivity, magnetic, gravity, ground penetrating radar and electro-magnetic are usually implemented to map out the archaeological evidences. It is often believed that the seismic refraction method may not be suitable when looking for anomalies of archaeological remains. However, since the purpose of this study is to delineate the boundary of shale to locate the ancient river, seismic refraction can give the very much desired result. The study was conducted at Sungai Batu, Kedah, Malaysia, which is famously known for its archaeological sites, including an ancient international entrepot. The discovery of jetty remains within the study area is also indicative of the existence of ancient river. The results obtained showed that the shale (suspected riverbed) are characterised with P-wave velocity of > 1822 m s–1. The suspected ancient river was determine based on a ravine shape that Topography Map of Sungai Batu 170 observed. It is believed that shale which is found at a depths of > 15 m is categorised as ancient river bed. It is concluded that the ancient river was probably flowing from NorthSouth direction towards East.
几十年来，地球物理方法在考古勘探中得到了广泛应用。这是因为这些方法为考古学家确定地表下埋藏的证据提供了大量的信息。与传统的考古探测技术相比，地球物理方法也具有成本效益，可以以相对较低的成本覆盖更大的区域。这些方法也是非破坏性和非侵入性的，在调查后保持考古遗址完全不受干扰。通常采用电阻率、磁力、重力、探地雷达和电磁等几种地球物理方法来绘制考古证据。人们常常认为，地震折射法可能不适用于寻找考古遗迹的异常。然而，由于本次研究的目的是圈定页岩边界以定位古河流，因此地震折射可以得到非常理想的结果。这项研究是在马来西亚吉打州的双盖峇都进行的，那里以其考古遗址而闻名，包括一个古老的国际转口港。研究区内的防波堤遗址的发现也证明了古河流的存在。结果表明，该页岩(疑似河床)的纵波速度为100 ~ 1822 m s-1。这条疑似古河流是根据《双溪拔图170》中观察到的峡谷形状确定的。研究认为，古河床的主要特征是发现于1 ~ 15 m深的页岩。推断该古河流可能是由南北向东流。
{"title":"Utilisation of Seismic Refraction Method in Producing Shale Topography Map of Sungai Batu Ancient River","authors":"S. Anda, R. Saad, M. Saidin, F. Andika, S. Muhammad, R. Yusoh","doi":"10.21315/JPS2019.30.1.12","DOIUrl":"https://doi.org/10.21315/JPS2019.30.1.12","url":null,"abstract":"Geophysical methods have been widely used in archaeological prospecting for decades. This is for the fact that the methods provide a great deal of information for archaeologist to determine buried evidences beneath the surface. Geophysical methods are also cost effective, covering much larger area at relatively lower costs, compared with the conventional archaeological probing techniques. The methods are also non-destructive and non-invasive, keeping archaeological sites entirely undisturbed after survey. Several geophysical methods including resistivity, magnetic, gravity, ground penetrating radar and electro-magnetic are usually implemented to map out the archaeological evidences. It is often believed that the seismic refraction method may not be suitable when looking for anomalies of archaeological remains. However, since the purpose of this study is to delineate the boundary of shale to locate the ancient river, seismic refraction can give the very much desired result. The study was conducted at Sungai Batu, Kedah, Malaysia, which is famously known for its archaeological sites, including an ancient international entrepot. The discovery of jetty remains within the study area is also indicative of the existence of ancient river. The results obtained showed that the shale (suspected riverbed) are characterised with P-wave velocity of > 1822 m s–1. The suspected ancient river was determine based on a ravine shape that Topography Map of Sungai Batu 170 observed. It is believed that shale which is found at a depths of > 15 m is categorised as ancient river bed. It is concluded that the ancient river was probably flowing from NorthSouth direction towards East.","PeriodicalId":16757,"journal":{"name":"Journal of Physical Science","volume":"24 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2019-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77175160","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}
The effect of ageing on properties of nickel oxide thin films deposited using spray pyrolysis technique was the focus of this study. Freshly prepared and aged nickel oxide films were successfully deposited by spray pyrolysis technique on a glass substrate at 350°C. The morphological, elemental, structural and optical properties of two different films were studied. The surface morphology was studied using field emission gun scanning electron microscope. The X-ray diffraction shows that both freshly prepared and aged films have a polycrystalline cubic structure with a preferred orientation along the (1 1 1) and (2 0 0) planes. Optical studies show a high transparency in the visible and near infrared regions. The band gap grew with ageing from 3.60 eV to 3.70 eV. The optical constant including the refractive index and extinction coefficient reduced with ageing. Based on the result obtained, the prepared sample can be used as the absorber layer of solar cells. The findings may open new frontiers in affordable and efficient solar cell fabrication in developing countries.
{"title":"Optimising Aged Nanostructured Nickel Oxide Thin Films for Solar Cells Fabrication","authors":"K. Ukoba, F. Inambao, A. Eloka‐Eboka","doi":"10.21315/JPS2019.30.1.1","DOIUrl":"https://doi.org/10.21315/JPS2019.30.1.1","url":null,"abstract":"The effect of ageing on properties of nickel oxide thin films deposited using spray pyrolysis technique was the focus of this study. Freshly prepared and aged nickel oxide films were successfully deposited by spray pyrolysis technique on a glass substrate at 350°C. The morphological, elemental, structural and optical properties of two different films were studied. The surface morphology was studied using field emission gun scanning electron microscope. The X-ray diffraction shows that both freshly prepared and aged films have a polycrystalline cubic structure with a preferred orientation along the (1 1 1) and (2 0 0) planes. Optical studies show a high transparency in the visible and near infrared regions. The band gap grew with ageing from 3.60 eV to 3.70 eV. The optical constant including the refractive index and extinction coefficient reduced with ageing. Based on the result obtained, the prepared sample can be used as the absorber layer of solar cells. The findings may open new frontiers in affordable and efficient solar cell fabrication in developing countries.","PeriodicalId":16757,"journal":{"name":"Journal of Physical Science","volume":"28 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2019-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90418243","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}
The rising carbon dioxide (CO2) emissions over the decades is known to be a huge contributor to the greenhouse effect. CO2 capture and storage methods have been perceived as favourable solutions to prevent global warming and climate change rising from the greenhouse effect. One energy efficient technology for separating CO2 is the development of high-performing CO2 gas separating membranes. A variety of membrane-based gas separation technologies designed have shown promising results and are inexpensive. A high-performing membrane must have a defect-free, thin dense skin-layer with a porous sub-layer for support that permits great permeation rate and selectivity. Of all ranges of polymers used to make polymeric membranes for CO2/nitrogen (N2) separation, cellulose acetate (CA) polymer membranes are known for their high CO2 solubility. In this research, the effect of CA polymer concentrations at low acetyl group of 39.8% and casting thickness on the structure and morphologies of the membranes were studied. The CA polymer concentration was optimised from a range of 10 wt%, 15 wt% and 20 wt%, and the casting thickness was optimised from a range of 150 μm to 400 μm using wet-phase inversion technique. The results obtained exhibit a CA membrane with thin dense, selective skin-layer achieved at CA polymer concentration of 15 wt% and a casting thickness of 300 μm, with a CO2 permeance rate of 401.173 ± 0.579 (GPU), N2 permeance rate of 133.499 ± 0.148 (GPU) and selectivity of 3.009 ± 0.00656. This CA membrane is able to contribute to promising gas separation performances with enhanced physical and mechanical support by improvement of membrane permeance and selectivity towards CO2/N2 separation performance.
{"title":"Formation of Low Acetyl Content Cellulose Acetate Membrane for CO2/N2 Separation","authors":"Lavania Sugu, Z. Jawad","doi":"10.21315/JPS2019.30.1.9","DOIUrl":"https://doi.org/10.21315/JPS2019.30.1.9","url":null,"abstract":"The rising carbon dioxide (CO2) emissions over the decades is known to be a huge contributor to the greenhouse effect. CO2 capture and storage methods have been perceived as favourable solutions to prevent global warming and climate change rising from the greenhouse effect. One energy efficient technology for separating CO2 is the development of high-performing CO2 gas separating membranes. A variety of membrane-based gas separation technologies designed have shown promising results and are inexpensive. A high-performing membrane must have a defect-free, thin dense skin-layer with a porous sub-layer for support that permits great permeation rate and selectivity. Of all ranges of polymers used to make polymeric membranes for CO2/nitrogen (N2) separation, cellulose acetate (CA) polymer membranes are known for their high CO2 solubility. In this research, the effect of CA polymer concentrations at low acetyl group of 39.8% and casting thickness on the structure and morphologies of the membranes were studied. The CA polymer concentration was optimised from a range of 10 wt%, 15 wt% and 20 wt%, and the casting thickness was optimised from a range of 150 μm to 400 μm using wet-phase inversion technique. The results obtained exhibit a CA membrane with thin dense, selective skin-layer achieved at CA polymer concentration of 15 wt% and a casting thickness of 300 μm, with a CO2 permeance rate of 401.173 ± 0.579 (GPU), N2 permeance rate of 133.499 ± 0.148 (GPU) and selectivity of 3.009 ± 0.00656. This CA membrane is able to contribute to promising gas separation performances with enhanced physical and mechanical support by improvement of membrane permeance and selectivity towards CO2/N2 separation performance.","PeriodicalId":16757,"journal":{"name":"Journal of Physical Science","volume":"32 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2019-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84128218","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}
Vertical axis wind turbines (VAWTs) extract energy through reduction of the kinetic and turbulent kinetic energies, and the vertical momentum flux. Detailed turbulence profiling and energy balance analysis were attempted through direct turbulence quantification using the Eddy Covariance method. A high-frequency sonic anemometer was employed to measure flow and turbulence upwind and downwind of a Darrieus-type VAWT at different positions that cover the entire windswept area. The data was processed and analysed using a custom Matlab script. Energy balance analysis showed that there was a significant drop in kinetic energy before and after the VAWT (72% to 42%) but a small increase in turbulent kinetic energy (28% to 31%). The results also showed that the rotational direction of VAWT contributed to a higher value of longitudinal turbulence at the windward edge of the VAWT. The VAWT affected the flow field upwind by generating reverse flows. The largest vertical momentum flux transfer occurred downwind of the windward side of the VAWT. Spectral analysis shows that the VAWT produced smaller but faster momentum flux vortices due to the rotating rotors in the 1 Hz to 5 Hz range. This data and results have important applications to accurately model complex flows around VAWTs.
{"title":"Energy Balance Analysis and Turbulence Profile of a Darrieus-type Vertical Axis Wind Turbine","authors":"Y. H’ng, Y. Yusup, S. A. Zaki","doi":"10.21315/JPS2019.30.1.5","DOIUrl":"https://doi.org/10.21315/JPS2019.30.1.5","url":null,"abstract":"Vertical axis wind turbines (VAWTs) extract energy through reduction of the kinetic and turbulent kinetic energies, and the vertical momentum flux. Detailed turbulence profiling and energy balance analysis were attempted through direct turbulence quantification using the Eddy Covariance method. A high-frequency sonic anemometer was employed to measure flow and turbulence upwind and downwind of a Darrieus-type VAWT at different positions that cover the entire windswept area. The data was processed and analysed using a custom Matlab script. Energy balance analysis showed that there was a significant drop in kinetic energy before and after the VAWT (72% to 42%) but a small increase in turbulent kinetic energy (28% to 31%). The results also showed that the rotational direction of VAWT contributed to a higher value of longitudinal turbulence at the windward edge of the VAWT. The VAWT affected the flow field upwind by generating reverse flows. The largest vertical momentum flux transfer occurred downwind of the windward side of the VAWT. Spectral analysis shows that the VAWT produced smaller but faster momentum flux vortices due to the rotating rotors in the 1 Hz to 5 Hz range. This data and results have important applications to accurately model complex flows around VAWTs.","PeriodicalId":16757,"journal":{"name":"Journal of Physical Science","volume":"10 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2019-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80341209","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}
Good stratigraphy mapping of a site is essential in archaeological explorations but Guar Kepah, Penang, Malaysia had no detailed subsurface mapping done previously up till now. As many archaeological remnants in the vicinity have an affiliation with shell middens, better understanding on Guar Kepah’s strata will increase the efficiency of uncovering the shell middens while also saving a huge amount of energy in excavating. This research aims to distinguish Guar Kepah’s buried shell midden from the surrounding strata using electrical resistivity method. The study area is composed of three shallow strata of unconsolidated soil with low resistivity values. The sandy-clay layer has the lowest resistivity (< 40 Ωm), followed by densely packed shell layer (40–70 Ωm) and sandy layer (> 70 Ωm). The presence of shells indicates that the uppermost strata is of marine origin, which automatically makes Gula Formation the youngest formation in Guar Kepah due to the absence of terrestrial deposits (Beruas Formation) on top of the layer. The shell layer from the resistivity profiles suggests that the layer has relatively uniform thickness throughout the site. The layer also becomes undulating and shallow towards the south (dipping), making the top sandy-clay soil become thinner or absent in the south. The dipping feature of the shell layer acts as an indicator that Guar Kepah used to be a beach ridge during sea transgression, and further proves that the area was once a marine environment. However, the shell layer at the southern zone poses an anomaly where it suddenly dips toward the centre. As a result, two zones were marked as potential shell middens at the south-western zone (only exhibits one side of the midden that is dipping towards centre) and south-eastern zone (shell midden elongated to the east). Subsequent excavation based on this study had successfully exposed the south-eastern midden and Shell Midden at Guar Kepah 100 proved that resistivity method could be used not only in stratigraphy identification, but also in characterising shell layer and detecting shell midden.
{"title":"Resistivity Characterisation of Shallow Stratigraphy in Delineating Shell Midden at Guar Kepah, Penang, Malaysia","authors":"N. Rosli, N. Ismail, H. Mansor, M. Saidin","doi":"10.21315/JPS2019.30.1.8","DOIUrl":"https://doi.org/10.21315/JPS2019.30.1.8","url":null,"abstract":"Good stratigraphy mapping of a site is essential in archaeological explorations but Guar Kepah, Penang, Malaysia had no detailed subsurface mapping done previously up till now. As many archaeological remnants in the vicinity have an affiliation with shell middens, better understanding on Guar Kepah’s strata will increase the efficiency of uncovering the shell middens while also saving a huge amount of energy in excavating. This research aims to distinguish Guar Kepah’s buried shell midden from the surrounding strata using electrical resistivity method. The study area is composed of three shallow strata of unconsolidated soil with low resistivity values. The sandy-clay layer has the lowest resistivity (< 40 Ωm), followed by densely packed shell layer (40–70 Ωm) and sandy layer (> 70 Ωm). The presence of shells indicates that the uppermost strata is of marine origin, which automatically makes Gula Formation the youngest formation in Guar Kepah due to the absence of terrestrial deposits (Beruas Formation) on top of the layer. The shell layer from the resistivity profiles suggests that the layer has relatively uniform thickness throughout the site. The layer also becomes undulating and shallow towards the south (dipping), making the top sandy-clay soil become thinner or absent in the south. The dipping feature of the shell layer acts as an indicator that Guar Kepah used to be a beach ridge during sea transgression, and further proves that the area was once a marine environment. However, the shell layer at the southern zone poses an anomaly where it suddenly dips toward the centre. As a result, two zones were marked as potential shell middens at the south-western zone (only exhibits one side of the midden that is dipping towards centre) and south-eastern zone (shell midden elongated to the east). Subsequent excavation based on this study had successfully exposed the south-eastern midden and Shell Midden at Guar Kepah 100 proved that resistivity method could be used not only in stratigraphy identification, but also in characterising shell layer and detecting shell midden.","PeriodicalId":16757,"journal":{"name":"Journal of Physical Science","volume":"113 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2019-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80580570","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}
A. Alnakhlani, Belqees Hassan, M. Ahlam, Muhammad Abdulhafiz
Samples of superconducting compounds were prepared by a solid-state reaction technique in a sealed quartz tube under normal pressure. The impact of the compound on the electrical properties has been studied using the electrical resistance measurements of the samples as a function of temperature. The obtained results appear that an enhancement in the phase formation, and the superconducting transition temperature Tc were improved. It may be due to the decreasing of the magnetic impurities or the delocalisation of carriers which resulted in the enhancement of the density of mobile carriers in the conducting CuO2 planes.
{"title":"Effect of Preparation and Annealing Temperature on the Properties of (Hg,Tl)-2223 Superconductor","authors":"A. Alnakhlani, Belqees Hassan, M. Ahlam, Muhammad Abdulhafiz","doi":"10.21315/JPS2019.30.1.6","DOIUrl":"https://doi.org/10.21315/JPS2019.30.1.6","url":null,"abstract":"Samples of superconducting compounds were prepared by a solid-state reaction technique in a sealed quartz tube under normal pressure. The impact of the compound on the electrical properties has been studied using the electrical resistance measurements of the samples as a function of temperature. The obtained results appear that an enhancement in the phase formation, and the superconducting transition temperature Tc were improved. It may be due to the decreasing of the magnetic impurities or the delocalisation of carriers which resulted in the enhancement of the density of mobile carriers in the conducting CuO2 planes.","PeriodicalId":16757,"journal":{"name":"Journal of Physical Science","volume":"146 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2019-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77618834","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 : 2019-05-15DOI: 10.21315/JPS2019.30.1.13
U. Reuben, A. F. Ismail, A. Ahmad, H. Maina, Aziah Daud
Indoor air quality refers to the air quality in and around laboratory buildings and facilities, which directly affects the health and comfort of workers. Poor air quality poses numerous health challenges to the laboratory workers and environment, and causes sick building syndrome (SBS) among workers. The objective of this study is to determine associations of SBS related to indoor air concentration in a dose-dependent manner among Nigerian laboratory university workers. This was a cross-sectional study on a population-based sample of Nigerian university laboratories and the workers. Data were collected using an indoor air quality control meter, dosimeter tubes gases of interest, and a set of questionnaires (MM-40). The results showed that the mean indoor air concentrations in a dose-dependent manner for chemical parameters range from 473.0 ppm to753.0 ppm, 17.9 ppm to 27.3 ppm, 5.7 ppm to 8.5 ppm, and 6.3 ppm to 9.1 ppm for CO2 , CO, NO2, H2S and SO2 , respectively. The prevalence of SBS, i.e., skin-related syndrome (SRS) is 38.5%, general-related symptom (GRS) is 28.3%, mucosal-related symptom (MRS) is 19.2% and at least one score was a respiratory-related symptom (RRS), which is 13.9%. The significant associated factors of SBS revealed by multinomial logistic regression in this study were NO2 [SRS (P = 0.022), GRS (P = 0.023), MRS (P = 0.032)], H2 S [SRS (P = 0.031), GRS (P < 0.001), MRS (P = 0.021)], and SO2 [SRS (P = 0.001), GRS (P < 0.001), MRS (P = 0.022)]. On the other hand, office laboratory temperature and relative humidity were shown to be negatively statistically associated with prevalence symptoms relative to RRS. In this study, SBS was found to be high. Indoor air concentration Air Quality and SBS Syndrome 180 in a dose-dependent manner and environmental parameters could increase the prevalence and incidence of SBS-related symptoms. Therefore, it is important to educate the workers on occupational and environmental health at a workplace to minimise SBS in the future.
{"title":"Indoor Air Quality and Sick Building Syndrome Among Nigerian Laboratory University Workers","authors":"U. Reuben, A. F. Ismail, A. Ahmad, H. Maina, Aziah Daud","doi":"10.21315/JPS2019.30.1.13","DOIUrl":"https://doi.org/10.21315/JPS2019.30.1.13","url":null,"abstract":"Indoor air quality refers to the air quality in and around laboratory buildings and facilities, which directly affects the health and comfort of workers. Poor air quality poses numerous health challenges to the laboratory workers and environment, and causes sick building syndrome (SBS) among workers. The objective of this study is to determine associations of SBS related to indoor air concentration in a dose-dependent manner among Nigerian laboratory university workers. This was a cross-sectional study on a population-based sample of Nigerian university laboratories and the workers. Data were collected using an indoor air quality control meter, dosimeter tubes gases of interest, and a set of questionnaires (MM-40). The results showed that the mean indoor air concentrations in a dose-dependent manner for chemical parameters range from 473.0 ppm to753.0 ppm, 17.9 ppm to 27.3 ppm, 5.7 ppm to 8.5 ppm, and 6.3 ppm to 9.1 ppm for CO2 , CO, NO2, H2S and SO2 , respectively. The prevalence of SBS, i.e., skin-related syndrome (SRS) is 38.5%, general-related symptom (GRS) is 28.3%, mucosal-related symptom (MRS) is 19.2% and at least one score was a respiratory-related symptom (RRS), which is 13.9%. The significant associated factors of SBS revealed by multinomial logistic regression in this study were NO2 [SRS (P = 0.022), GRS (P = 0.023), MRS (P = 0.032)], H2 S [SRS (P = 0.031), GRS (P < 0.001), MRS (P = 0.021)], and SO2 [SRS (P = 0.001), GRS (P < 0.001), MRS (P = 0.022)]. On the other hand, office laboratory temperature and relative humidity were shown to be negatively statistically associated with prevalence symptoms relative to RRS. In this study, SBS was found to be high. Indoor air concentration Air Quality and SBS Syndrome 180 in a dose-dependent manner and environmental parameters could increase the prevalence and incidence of SBS-related symptoms. Therefore, it is important to educate the workers on occupational and environmental health at a workplace to minimise SBS in the future.","PeriodicalId":16757,"journal":{"name":"Journal of Physical Science","volume":"9 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2019-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82435409","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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