Tailoring the properties of polyamide thin film membrane with layered double hydroxide nanoclay for enhancement in water separation

Tajuddin M.H.,Yusof N.,Fajrina N.,Salleh W.N.W.,Ismail A.F.,Jaafar J.,Aziz F. 한국물리학회 2022 Current Applied Physics Vol.34 No.-

This current paper presented a new candidate and potentially to improve the current membrane materials in water filtration process. With that, the primary materials used in this research study is layered double hydroxides (LDH) nanoclay which can be obtained from earth minerals and self-synthesized from inorganic salts were discussed thoroughly to help a better understanding of these materials. However, the current technologies of water separation were still lagging behind and ineffective especially in removal of divalent metal ions and multivalent salts. Infeasibility of reverse osmosis membrane make it not a viable option for divalent salts filtration. With that, nanofiltration (NF) membrane offered as an alternative to substitute available method. In this study, thin film nanocomposite (TFN) membranes were fabricated by incorporating layered double hydroxides (LDH) nanoclay. The LDH nanoclay with different loading ratio of 0, 0.05, 0.1, 0.15 and 0.2 were impregnated into polyamide layer on top of polysulfone substrates. The fabricated TFN were characterized in terms of physicochemical properties (SEM and FTIR) and membrane hydrophilicity (contact angle). After the addition of LDH, the morphological structures of TFN membranes were changed and the surface hydrophilicity was enhanced significantly. FESEM images displayed a typical ridge and valley morphology with nodule-like structures. As the LDH loading was increased, the contact angle decreased from 34.56◦ to 15.76◦ showing the surface hydrophilicity of membrane is improved. The separation performance of membrane was evaluated in terms of salt rejection ability by cross flow filtration system. The best performance NF membrane was found to be TFN 0.05 with high water flux and MgCl2 rejection with values of 24.18 L/m2.h and 91% respectively. This study has experimentally validated the potential of LDH materials in membrane process for improvement in water separation process.

The Malaysian Media : Current Situation and Challenges Ahead

Ahmad Tajuddin Baharuddin 연세대학교 커뮤니케이션연구소 1997 언론 사회 문화 Vol.- No.6

The Malaysian Media : Current Situation and Challenges Ahead

Baharuddin, Ahmad Tajuddin 연세대학교 언론연구소 1997 언론 사회 문화 Vol.- No.6

Effects of Aquatic Training on Waist Circumference and Body Composition among Children: A Meta-analysis

Jianming Zhou,Ahmad Tajuddin Othman,Ahmad Zamri Khairani 한국운동생리학회 2022 운동과학 Vol.31 No.3

PURPOSE: Aquatic training assists in reducing the risk of exercise on joints among children. This systematic review evaluated the effectiveness of aquatic training for children from the perspective of body composition. METHODS: A meta-analysis was performed to determine the potential impact of aquatic training in children. Four databases, namely Scopus, PubMed, Web of Science, and EBSCO, were used for the systematic search from September 2010 to November 2021. The mean differences in the data were analyzed using Stata 15.1 software with a 95% confidence interval. Outcome measures included weight, body mass index (BMI), fat percentage (Fat%), and waist circumference. RESULTS: Eleven studies, comprising eight randomized controlled trials (RCT) and three non-RCT studies, evaluating the effect of aquatic training on children were analyzed and reported. Aquatic training significantly improved the BMI (p<.01) and Fat% (p<.01) in children (ES (95% CI)=-0.23 (-0.38, -0.08) and ES (95% CI)=-0.27 (-0.45, -0.08). However, aquatic training had no significant effect on weight (p=.41), ES (95% CI)=-0.07 (-0.25, 0.10), and waist circumference (p=.11) in children, ES (95% CI)=-0.33 (- 0.74, 0.08). CONCLUSIONS: Aquatic training can improve children’s BMI and body fat% but not their weight, waist circumference, and muscle mass. Aquatic training may be a potential exercise program for improving body composition in children.

Biogenic fabrication and characterization of silver nanoparticles using aqueous-ethanolic extract of lichen (Usnea longissima) and their antimicrobial activity

Khwaja Salahuddin Siddiqi,M. Rashid,A. Rahman,Tajuddin,Azamal Husen,Sumbul Rehman 한국생체재료학회 2018 생체재료학회지 Vol.22 No.4

Background: Biogenic fabrication of silver nanoparticles from naturally occurring biomaterials provides an alternative, eco-friendly and cost-effective means of obtaining nanoparticles. It is a favourite pursuit of all scientists and has gained popularity because it prevents the environment from pollution. Our main objective to take up this project is to fabricate silver nanoparticles from lichen, Usnea longissima and explore their properties. In the present study, we report a benign method of biosynthesis of silver nanoparticles from aqueous-ethanolic extract of Usnea longissima and their characterization by ultraviolet–visible (UV-vis), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analyses. Silver nanoparticles thus obtained were tested for antimicrobial activity against gram positive bacteria and gram negative bacteria. Results: Formation of silver nanoparticles was confirmed by the appearance of an absorption band at 400 nm in the UV-vis spectrum of the colloidal solution containing both the nanoparticles and U. longissima extract. Poly(ethylene glycol) coated silver nanoparticles showed additional absorption peaks at 424 and 450 nm. FTIR spectrum showed the involvement of amines, usnic acids, phenols, aldehydes and ketones in the reduction of silver ions to silver nanoparticles. Morphological studies showed three types of nanoparticles with an abundance of spherical shaped silver nanoparticles of 9.40–11.23 nm. Their average hydrodynamic diameter is 437.1 nm. Results of in vitro antibacterial activity of silver nanoparticles against Staphylococcus aureus, Streptococcus mutans, Streptococcus pyrogenes, Streptococcus viridans, Corynebacterium xerosis, Corynebacterium diphtheriae (gram positive bacteria) and Escherichia coli, Klebsiella pneuomoniae and Pseudomonas aeruginosa (gram negative bacteria) showed that it was effective against tested bacterial strains. However, S. mutans, C. diphtheriae and P. aeruginosa were resistant to silver nanoparticles. Conclusion: Lichens are rarely exploited for the fabrication of silver nanoparticles. In the present work the lichen acts as reducing as well as capping agent. They can therefore, be used to synthesize metal nanoparticles and their size may be controlled by monitoring the concentration of extract and metal ions. Since they are antibacterial they may be used for the treatment of bacterial infections in man and animal. They can also be used in purification of water, in soaps and medicine. Their sustained release may be achieved by coating them with a suitable polymer. Silver nanoparticles fabricated from edible U. longissima are free from toxic chemicals and therefore they can be safely used in medicine and medical devices. These silver nanoparticles were stable for weeks therefore they can be stored for longer duration of time without decomposition.

The Reaction of the Malaysian Stock Market to the COVID-19 Pandemic

Mehmood, Waqas,Mohd-Rashid, Rasidah,Aman-Ullah, Attia,Shafique, Owais,Tajuddin, Ahmad Hakimi World Association for Triple Helix and Future Stra 2021 Journal of Contemporary Eastern Asia Vol.20 No.2

The present study was conducted to understand the turmoil effects of COVID-19 pandemic on the Malaysian stock market during the different periods of the Movement Control Order (MCO). The present study was based on the secondary data extracted from the DataStream and Bloomberg from 2nd January 2020 to 29th May 2020 to evaluate the effects of COVID-19 pandemic on the Malaysian stock market. The findings suggested that during the different periods of the Movement Control Order (MCO) from the 1st January to 29th May 2020, the COVID-19 pandemic adversely affected the performance of KLCI index and all sectoral indices. The weakest performance indices were energy, property, and finance while the least affected indices were healthcare, technology, telecommunications, and media. This paper provides a review of the impacts of COVID-19 pandemic on the Malaysian stock market throughout the different periods of MCO.

New evidence of Lockup Provisions: Effects on IPO Demands

Mohd-Rashid, Rasidah,Khaw, Karren Lee-Hwei,Mehmood, Waqas,Tajuddin, Ahmad Hakimi World Association for Triple Helix and Future Stra 2022 Journal of Contemporary Eastern Asia Vol.21 No.1

This study examines the impacts of a mandatory lockup ratio and lockup period, together with voluntary lockup, on the initial public offering (IPO) subscription rate in Malaysia. A sample of 390 IPOs launched from 2000 to 2016 was collected for analysis. The findings show that firms that adopt a lower lockup ratio and a shorter lockup period signal uncertainty about their prospects. Issuers would then show the tendency to underprice to increase investors' intention to subscribe to firms' IPO shares. This study concludes that as long as investors are aware of pertinent information about IPO firms, they should continue participating in the IPO market rather than behaving irrationally. Finally, policymakers could use the findings to improve the existing lockup provisions regulation.

Empirically Based Rainfall Threshold for Landslides Occurrence in Peninsular Malaysia

Abdul Muaz Abu Mansor Maturidi,Norhidayu Kasim,Kamarudin Abu Taib,Wan Nur Aifa Wan Azahar,Husna Binti Ahmad Tajuddin 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.12

Empirical rainfall thresholds for the purpose of shallow landslide forecasting are proposed for Peninsular Malaysia where numerous slope failures are reported due to the intense rainfall in conjunction with the humid tropical climate. Thirty-seven cases of landslide-triggering-rainfall were selected from 1993 to 2018 to identify the correlation between rainfall and shallow landslide through the analysis of specific rainfall events. The derived rainfall parameters were applied to establish two rainfall thresholds of (Imean-D) and (Imax-D) via practical methods. For the identical range of event duration 1 < D < 263 h, the (Imean-D) threshold formula was expressed as I = 17.5 D−0.722, while the (Imax-D) threshold was defined as I = 37.8 D−0.114. Both thresholds performed different functionalities with a primary goal of predicting shallow landslides. When both (Imean-D) and (Imax-D) thresholds were compared with the thresholds proposed by various studies worldwide, both dominated the upper positions. More rainfall is required for land sliding due to the high thickness of the Malaysian soil that is associated with the abundant tropical downpour. From the perspective of the antecedent, the period of prolonged precipitation or short heavy rainfall from 1 to 10 days can result in shallow landslides for Peninsular Malaysia. In the context of geology, the igneous rock type of granite has the highest susceptibility to the shallow landslide at 65%, despite other rock types of sedimentary and metamorphic. The threshold validation depicted all True Positive events for the (Imax-D) threshold, and one Negative False event for the (Imean-D) threshold. The (Imean-D) threshold was revised to acquire the new value, but it needed to deal with the possibility of False Alarm and the (Imax-D) threshold seemed to be more credible to represent the rainfall-induced shallow landslide threshold for Peninsular Malaysia.

Extended Technology Acceptance Model for Enhanced Distribution Strategies to Online Learning: Application of Phantom Approach

Izzat ISMAIL,Asyraf AFTHANORHAN,Noor Aina Amirah MOHAMAD NOOR,Nurul Aisyah Awanis A RAHIM,Sheikh Ahmad Faiz Sheikh Ahmad TAJUDDIN,Muhammad Takiyuddin Abdul GHANI 한국유통과학회 2024 유통과학연구 Vol.22 No.4

Purpose: This study is aimed to introduce the application of phantom approach with structural equation modelling method for online learning. By integrating these innovative methodologies, the research seeks to advance the understanding of how the phantom approach can effectively complement and augment structural equation modeling techniques. Research design, data and methodology: A theoretical framework of Technology Acceptance Model (TAM) was modified and updated. A questionnaire was developed and used to extract information from 189 instructors who used online learning as their primary medium. The Covariance Based Structural Equation Modelling (CBSEM) was applied to test the direct effects and the phantom approach is used to handle the 2 mediators in the model. Results: social influence, perceived usefulness, and perceived ease of use exerted discernible impacts on instructors' intentions to engage in online learning. These findings illuminate the intricate dynamics influencing instructor behavior within the realm of online education, underscoring the significance of various factors in shaping their intentions. Conclusions: In additions, the perceived usefulness and perceived ease of use had mediated the effect of social influence and instructor intention using phantom approach. Therefore, one can have concluded that this modified model was also confirmed, thereby reinforcing distribution strategies to online learning and overall education presence.

Correction: Single-trait and multi-trait genome-wide association analyses identify novel loci for blood pressure in African-ancestry populations

Liang, Jingjing,Le, Thu H.,Velez Edwards, Digna R.,Tayo, Bamidele O.,Gaulton, Kyle J.,Smith, Jennifer A.,Lu, Yingchang,Jensen, Richard A.,Chen, Guanjie,Yanek, Lisa R.,Schwander, Karen,Tajuddin, Salman Public Library of Science 2018 PLoS genetics Vol.14 No.5