Study mass transfer of Cd, Hg, As, DDT and chlordane through adsorption onto granular activated carbon

The kinetic theory of liquid indicates that diffusion coefficient for the dilute liquid at ordinary pressure is essentially independent of mixture composition. Mass transfer is important in separation and adsorption process. However, diffusion may also be caused by other features. Because of the complex nature of mass diffusion, the diffusion coefficients are usually determined experimentally. The mass transfer resistance controls the kinetic adsorption rate, but there is only limited understanding of the adsorption of a solute onto porous material from surface water. Thus, this study was conducted to further enhance the understanding of the mass transfer and adsorption processes of micropollutants. The objectives of this study are to analyze the difference, examine the adsoprtion diffusion of mass transfer and evaluate the variation of total, internal and external mass transfer. This study also used the transformed equation to analyze the rate of adsorption during adsorption process onto different GACs. Five (5) micropollutants namely Hg, Cd, As, DDT and chlordane have been chosen to be adsorbed onto three (3) granular activated carbon which are SIG (shell industrial grade), SAG (shell analytical grade) and BAG (bitumen analytical grade). The micropollutants (Hg, Cd, As, DDT and chlordane) were prepared using standard stock solution in deionized water. Adsorption of pollutants onto SIG, SAG, and BAG were started at different percentages of outflow. Although the samples were taken at the same time, the outcome showed that a significant competition between adsorbates and adsorbents. From the analysis, SIG and SAG displayed excellent performance in adsorbing inorganic micropollutants while BAG for organic micropollutants. Before adsorption takes place, the morphology of the SAG indicated pore abundance compared to SIG and BAG. BAG pores are more structured than SIG and SAG. After adsorption occurs, more of the organic micropollutants are being adsorbed onto BAG and SAG. Meanwhile, SIG proved to be the best adsorbent for inorganic micropollutants. It takes 72 hours for Hg vi and As to saturate SIG whilst Cd take a longer time of 80 hours. SAG was also a good adsorbent for organic elements, with DDT taking 52 hours and chlordane taking 48 hours to be adsorbed. The [KLa]f value for the adsorption of Hg onto SIG was significant and the [KLa]d value for the adsorption of Hg onto SIG was higher onto SAG and BAG. The value of [KLa]f for SIG at 6% outflow was 0.6862 h-1, with values of [KLa]d at -0.4142 h-1 and [KLa]g at 0.2721 h-1, while for the adsorption of Cd it was shown that the [KLa]f values for the adsorption of Cd onto BAG was the most significant and the [KLa]d values for the adsorption of Cd onto SIG was higher than SAG and BAG at 2% outflow, with values of 0.7044 h-1, [KLa]d at -0.3687 h-1, and [KLa]g at 0.3356 h-1. In contrast, for As the [KLa]f for the adsorption of As onto BAG at 4% outflow was 0.6722 h-1 and [KLa]g was 0.3103 h-1. For DDT, the [KLa]f value of DDT for BAG at 0.5% outflow was 1.6662 h-1, [KLa]d was -1.2702 h-1 and [KLa]g was 0.3959 h-1. In the case of DDT, the value of [KLa]f for the adsorption of chlordane onto BAG at 2% outflow was 0.7330 h-1 and [KLa]d was started to activate the adsorption -0.5567 h-1. [KLa]g at 2% outflow was 0.1763 h-1. From these values we can conclude that for the adsorption of inorganic substances, SIG proved to be the best, while for organic substances BAG is the best adsorbent

Understanding of mass transfer resistance for the adsorption of solute onto porous material from the modified mass transfer factor models

Mass transfer is important in separation and is essential for adsorption process. Mass transfer resistance controls the adsorption kinetic rate, but there is only limited understanding of the adsorption of a solute onto porous material from surface water. This study investigates the adsorptions of NH4þ and Al3+ onto granular activated carbon from surface water using the laboratory-scale plug flow column. The use of the modified mass transfer models is able to determine the resistance of mass transfer for the adsorption of one or more solutes present in surface water onto porous material. In this case study identified that the resistance of mass transfer is dependent on film mass transfer before and porous diffusion after break-through occurred. The research findings advance understanding of novel approach for investigating mass transfer resistance of solute onto porous material from waters

Comparative study of turbulent incompressible flow past naca airfoils

The flow past the airfoils is continuously investigated in various experimental and computational aerodynamic perspectives. In this paper, a comparative study on the aerodynamic characteristics of the turbulent incompressible flow past four NACA airfoils is emphasized. Particularly, we classify these characteristics based on the basic geometries, namely symmetric and asymmetric airfoils, as well as trailing edge angles. The results confirm the general aerodynamic theory and include finding on the effect of sharp trailing edge, which complement the available airfoil datasets for improving their designs and as reference cases

Gabungan Peta Pemikiran I-Think dan Aplokasi Quizizz Dalam PDPR [Combination of I-Think Thinking Map and Quizizz Application in PDPR]

Ez i-Think merupakan satu teknik pengajaran yang menggabungkan peta pemikiran i-Think dengan aplikasi Quizizz dan Google Classroom. Pembelajaran Abad ke-21 amat menekankan teknik pengajaran dan pembelajaran (PdP) yang menggunakan teknologi digital. Selaras dengan hasrat Pelan Pembangunan Pendidikan Malaysia dalam Gelombang ketiga iaitu meningkatkan inovasi dalam kalangan guru, maka ez i-Think menjadi idea kepada penggunaan peta pemikiran i-Think dalam pengajaran dan pembelajaran secara online mahupun offline. Reka bentuk kajian ini menggunakan pendekatan kuantitatif jenis tinjauan. Data dianalisis daripada sampel soal selidik yang diadaptasi daripada Davis F.D (1989). Sampel kajian terdiri daripada 41 orang murid Tingkatan Dua di SM Sains Sultan Mahmud yang dipilih secara rawak daripada jumlah populasi seramai 112 orang. Analisis deskriptif yang digunakan ialah peratus, min dan sisihan piawai. Manakala analisis inferensi menggunakan ujian-T. Dapatan kajian menunjukkan bahawa tahap kebolehgunaan dan kemudahgunaan terhadap pelaksanaan ez i-Think adalah berada pada tahap yang tinggi. Kajian ini juga mendapati tidak wujud perbezaan yang signifikan dalam kebolehgunaan dan kemudahgunaan dari aspek jantina. Hasil kajian ini dapat menjadi panduan kepada pihak sekolah dan KPM untuk meningkatkan penggunaan peta pemikiran i-Think agar seiring dengan hasrat Pelan Pembangunan Pendidikan Malaysia 2013-2025. Ez i-Think is a teaching technique that combines i-Think mind maps with Quizizz and Google Classroom applications. 21st Century Learning places great emphasis on teaching and learning techniques that use digital technology. In line with the intention of the Malaysian Education Development Plan in the third wave, which is to increase innovation among teachers, ez i-Think is an idea for the use of i-Think mind maps in online and offline teaching and learning. The design of this study uses a survey method type quantitative approach. Data were analyzed from a sample of questionnaires adapted from Davis. The study sample consisted of 41 Form Two students at SM Sains Sultan Mahmud who were randomly selected from a total population of 112 people. The descriptive analyzes used were percentage, mean and standard deviation. Whereas inferential analysis using T-test. The findings show that the level of usability and usability of the implementation of ez i-Think is at a high level. The study also found that there were no significant differences in usability and usability from the aspect of gender. The results of this study can be a guide to schools and MOE to increase the use of i-Think mind maps in line with the aspirations of the Malaysian Education Development Plan 2013-2025.Ez i-Think merupakan satu teknik pengajaran yang menggabungkan peta pemikiran i-Think dengan aplikasi Quizizz dan Google Classroom. Pembelajaran Abad ke 21 amat menekankan teknik pengajaran dan pembelajaran yang menggunakan teknologi digital. Selaras dengan hasrat Pelan Pembangunan Pendidikan Malaysia dalam Gelombang ketiga iaitu meningkatkan inovasi dalam kalangan guru, maka ez i-Think menjadi idea kepada penggunaan peta pemikiran i-Think dalam pengajaran dan pembelajaran secara online mahupun offline. Reka bentuk kajian ini menggunakan pendekatan kuantitatif jenis kaedah tinjauan. Data dianalisis daripada sampel soal selidik yang diadaptasi daripada Davis. Sampel kajian terdiri daripada 41 orang murid Tingkatan Dua di SM Sains Sultan Mahmud yang dipilih secara rawak daripada jumlah populasi seramai 112 orang. Analisis deskriptif yang digunakan ialah peratus, min dan sisihan piawai. Manakala analisis inferensi menggunakan ujian-T. Dapatan kajian menunjukkan bahawa tahap kebolehgunaan dan kemudahgunaan terhadap pelaksanaan ez i-Think adalah berada di tahap yang tinggi. Kajian ini juga mendapati tidak wujud perbezaan yang signifikan dalam kebolehgunaan dan kemudahgunaan dari aspek jantina. Hasil kajian ini dapat menjadi panduan kepada pihak sekolah dan KPM untuk meningkatkan penggunaan peta pemikiran i-Think agar seiring dengan hasrat Pelan Pembangunan Pendidikan Malaysia 2013-2025

Group cognitive behavioral therapy for aggression, self-control, and social support among first grade university students of China

The objective of this study was to determine the intervention effect of group cognitive behavioral therapy (G-CBT) for aggression, selfcontrol, and social support among first grade university students of China. This research was a randomized pre- and post-test with control group design. Through stratified random sampling, 1,469 first grade university students, age from 18- to 19-year-old, were obtained. The participants whose score achieved aggressive evaluation standard were selected, and in a random way, 60 subjects were averagely divided into two schemes - G-CBT and the control group. The subjects of G-CBT received 16 sessions of treatment, while subjects in the control group did not receive any intervention. All subjects completed the assessment for 3 times: Pre-test (1 week before intervention), post-test 1 (1 week after intervention), and post-test 2 (4 months after intervention). The results showed that the total score and the scores of all subscales of aggression had dropped significantly (P 0.05). Therefore, the G-CBT was effective in treating aggression and the effect was stable; the G-IPT was effective in improving social support, but the effect was not stable; and the self-control level of G-CBT group improved but did not reach significance degree in this study

An examination of pre-service teachers' goal orientations, self-regulation and active procrastination

This study examined the relationships between intrinsic goal orientation, extrinsic goal orientation, self-regulation and active procrastination; and the mediating role of self-regulation in these relationships. A total of 426 pre-service teachers (223 males, 203 females) studying in colleges of education in Nigeria participated in the study. A set of self-report questionnaire was used to measure the participants’ levels of procrastination, goal orientations, and self-regulation. Structural equation modelling (SEM) using AMOS software was employed as statistical technique for data analysis of the study. The findings, based on the hypothesized structural model, which overall goodness-of-fit indices indicate good model fit revealed that, while extrinsic goal orientation was found to be directly significant predictor of active procrastination, intrinsic goal orientation was not. However, mediation analysis, based on SEM or modern approach, indicated that there was an evidence of indirect effects of the predictor variables on active procrastination through self-regulation. Test of mediation by bootstrapping method established significant mediating role of self-regulation in the relationships between intrinsic goal orientation and extrinsic goal orientation and active procrastination. Conclusion and implications of the study have been highlighted

Kepelbagaian dan kelimpahan foraminifera di sedimen permukaan sekitar Delta Sungai Kelantan, Malaysia

Suatu kajian telah dijalankan untuk menentukan kepelbagaian dan kelimpahan foraminifera di sedimen permukaan sekitar delta Sungai Kelantan memandangkan kajian foraminifera terutamanya di perairan marin Malaysia amat kurang. Sejumlah 22 stesen daripada dua garisan transek telah ditentukan sebagai kawasan persampelan. Sebanyak 10,317 individu foraminifera yang terdiri daripada 27 famili, 34 genus dan 55 spesies telah ditemui di kawasan kajian. Secara keseluruhannya, famili Hauerinidae mencatatkan kepelbagaian spesies tertinggi (10 spesies) manakala famili paling dominan dengan jumlah individu tertinggi ialah Rotaliidae (26.14%). Spesies dominan dan paling melimpah di kawasan kajian ialah Asterorotalia pulchella (17.24%) dan Operculina ammonoides (10.19%). Indeks kepelbagaian spesies, H’ yang dicatatkan ialah antara 0.5 hingga 3.1 manakala indeks kekayaan spesies, α adalah antara 1.5 hingga 7.9. Kelimpahan dan kepelbagaian spesies tertinggi (α=7.9, H’=3.1) dicatatkan pada stesen 21 yang terletak di laut terbuka dengan kedalaman air sebanyak 36.8 m dan bersaliniti 32.2 ppt mendekati laut normal. Nilai H’ dan α terendah dicatatkan pada stesen yang berdekatan dengan muara sungai yang cetek dan bersaliniti lebih rendah. Secara keseluruhannya, nilai indeks kepelbagaian yang dicatatkan di kawasan kajian adalah menepati persekitaran marin berair cetek. Kesimpulannya, kepelbagaian dan kelimpahan foraminifera di kawasan kajian dipengaruhi oleh kedalaman dan saliniti air

A multi-aspect agent-based model of covid-19: disease dynamics, contact tracing interventions and shared space-driven contagions

In the quest to better understand the epidemic dynamics of COVID-19 and possible strategies to mitigate its impact, a wide range of simulation models have been developed for various purposes. Faced with a novel disease with little-known characteristics and an unprecedented impact, the need arises to model multiple aspects with very dissimilar dynamics in a consistent, formal, yet flexible and quick way, in order to then study the combined interaction of these dynamics. We present an agent-based model combining kinematic movement of agents, interaction between them and their surrounding space and a top-down control over the entire population. To achieve this, we extend the retQSS framework to model and simulate particle systems interacting with geometries. In this work, we study different contact tracing strategies and their efficacy in a population undergoing an epidemic process driven mainly by airborne infections in indoor environments.Fil: Lanzarotti, Esteban Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Investigación en Ciencias de la Computación. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Investigación en Ciencias de la Computación; ArgentinaFil: Roslan, Francisco. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Computación; ArgentinaFil: Groisman, Leandro. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Computación; ArgentinaFil: Santi, Lucio Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Investigación en Ciencias de la Computación. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Investigación en Ciencias de la Computación; ArgentinaFil: Castro, Rodrigo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Investigación en Ciencias de la Computación. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Investigación en Ciencias de la Computación; ArgentinaWinter Simulation Conference 2021: Simulation for a Smart World: From Smart Devices to Smart CitiesPhoenixEstados UnidosOrganizing Committee of Simulation Conferenc

Isolation of bacteria from the acidic peat swamp forest soil and their lignin degradation potential

The tropical peat swamp forest in Malaysia has reduced significantly due to increasing pressure for development and demand for agricultural land. Pekan peat swamp forest is part of the 200,000 hectares of peat swamp forest located in Pahang, Peninsular Malaysia. While more extensive studies were done on flora and fauna, the study on microbial diversity in this habitat is very limited. The highly acidic environment, low concentrations of nutrients and anoxic condition of the peat are among challenges that hampered the cultivation of microorganism from this environment. In this study two types of agar-based medium, M1 minimal medium (M1) and peat water medium (PW) supplemented with glucose, methanol and lignin were used to isolate bacteria from the peat sediment. In comparison to M1, the use of PW has resulted with higher number of isolates with different morphologies. The PW mainly contains the acidic peat water that was collected from the sampling location. Based on the growth on medium supplemented with lignin, selected isolates were identified using 16s rDNA sequencing. At least three of the isolates showed sequence similarity to Burkholderia sp., which is one of the common species, studied on their ligninase-producing abilities. The results from this study serve as the preliminary data for further work on growth characteristics and enzymatic potential of isolates from acidic peat swamp soil

Tren guna tenaga buruh mengikut sektor pekerjaan dan tahap pendidikan dari tahun 2001 hingga 2012

Indeks Kemakmuran Legatum menyenaraikan lapan sub-indeks yang merangkumi 89 pemboleh ubah untuk pengukuran kemakmuran Negara.Aspek ekonomi termasuk pemboleh ubah guna tenaga dan aspek tahap pendidikan kekal sebagai penyumbang utama kepada kemakmuran sesebuah negara bersama dengan sub-indeks pentadbiran, kesihatan, keselamatan, kebebasan peribadi, modal sosial dan peluang keusahawanan.Kertas ini menumpu kepada menganalisis tren guna tenaga mengikut sektor pekerjaan dan tahap pendidikan di Malaysia sepanjang tempoh dua belas tahun bermula tahun 2001 hingga 2012.Selain daripada situasi keseluruhan Malaysia, guna tenaga mengikut sektor pekerjaan dan tahap pendidikan mengikut pecahan negeri juga diberi perhatian.Kaedah analisis siri masa (time series analysis) berdasarkan data sekunder yang diperoleh daripada Jabatan Perangkaan Malaysia merupakan kaedah utama yang digunakan.Dapatan kajian menunjukkan guna tenaga buruh bertambah pada kadar purata 2.2 peratus setahun.Sektor perkhidmatan terus merupakan bahagian terbesar daripada jumlah guna tenaga buruh sejak tahun 2004 hingga tahun 2012 dan mengalami pertumbuhan guna tenaga buruh purata 4.2 peratus setahun.Sektor yang paling banyak mengalami penurunan dalam peratusan penggunaan tenaga buruh ialah sektor pekerja mahir pertanian, perhutanan dan perikanan.Guna tenaga di Negeri Selangor jauh lebih tinggi berbanding dengan negeri-negeri lain, diikuti oleh Johor dan Sabah. Analisis juga menunjukkan bahawa berlaku pertambahan mendadak dalam bilangan tenaga kerja yang berpendidikan tinggi bagi tempoh 12 tahun. Melalui analisis terperinci terhadap taburan guna tenaga dan tahap pendidikan tenaga buruh, kami akan dapat mengetahui situasi sebenar struktur ekonomi Malaysia yang boleh dijadikan sebagai satu rujukan penting untuk menilai keberkesanan dasar pembangunan Negara dalam usaha meningkatkan kesejahteraan rakyat sebagaimana yang dihasratkan oleh kerajaan Malaysia