153 results on '"Sharif, Zein"'
Search Results
2. REMOVAL OF METHYLENE BLUE FROM AQUEOUS PHASE BY PRETREATED WALNUT SHELL IN A PACKED COLUMN
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A.A. Nazari-Moghaddam, G.D. Najafpour, A.A. Ghoeyshi, M. Mohammadi, and harif Hussein Sharif Zein
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Adsorption ,Methylene blue ,Langmuir isotherm ,Walnut shell ,Packed column ,Environmental sciences ,GE1-350 - Abstract
Methylene blue (MB) adsorption from aqueous phase was investigated. Pretreated walnut shell, as adsorbent was used. Experiments were conducted in a batch system for determination of sorption equilibria and then the data were incorporated in a packed column for the removal of MB from synthetic wastewater. The generated wastewater was contained 4 mg/l of MB. The wastewater was pumped through the column with flow rate of 18 ml/min and the effluent samples were collected. The effect of influent MB concentration (4 and 8 mg/l) and pH (5, 7 and 9) of wastewater on removal efficiency of dye were investigated. Langmuir adsorption isotherm model was implemented to interpret the experimental data. The obtained results revealed that the sorption data were well described by Langmuir model at pH value of 9. At contact time of 300 min, maximum equilibrium adsorption of MB uptake 6.7mg/g adsorbent was achieved.
- Published
- 2010
3. Synthesis of a TiO 2 ceramic membrane containing SrCo 0.8Fe 0.2O 3 by the sol–gel method with a wet impregnation process for O 2 and N 2 permeation
- Author
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Ahmad, Abdul Latif, Abdullah Sani, Nur Aimie, and Sharif Zein, Sharif Hussein
- Published
- 2011
- Full Text
- View/download PDF
4. The examination of NiO and CoOx catalysts supported on Al2O3 and SiO2 for carbon nanotubes production by catalytic chemical vapor deposition of methane.
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Abdul Rahman Mohamed, Sharif Hussein Sharif Zein, V. M. Sivakumar, and Siang-Piao Chai
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Carbon Nanotube Synthesis ,Methane ,Supported Catalyst ,Al2O3 ,SiO2 ,Chemical engineering ,TP155-156 - Abstract
The effects of catalyst components on the synthesis of carbon nanotubes (CNTs) are always the concern of many. The aimof this work is to examine the dependence of the morphology of CNTs formed on the nature of NiO and CoOx catalystssupported on Al2O3 and SiO2 at two different synthesis temperatures, i.e. 550oC and 700oC, respectively. Catalytic chemicalvapor deposition (CCVD) of methane was adopted for synthesizing the nanotubes materials. The developed catalysts werecharacterized by X-ray diffraction (XRD) and temperature programmed reduction (TPR). The morphology of the producedcarbon nanostructures was analyzed by transmission electron microscopy (TEM). The experimental result shows that CNTswere presence on the surfaces of most of the tested catalysts. The yield of the CNTs produced over these catalysts wascalculated. It was found that the yield decreased in the order of NiO/SiO2>CoOx/SiO2>CoOx/Al2O3>NiO/Al2O3 for thereaction at 550oC and in the order of NiO/SiO2>CoOx/Al2O3>CoOx/SiO2>NiO/Al2O3 at 700oC. The morphological analysisreveals that the structure of the CNTs depends upon the effects of metal-support interaction (MSI) and the synthesistemperature.
- Published
- 2008
5. Outcomes of Patients Presenting with Mild Acute Respiratory Distress Syndrome
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Gerard Curley, Lorenzo Schiavoni, Giacomo Monti, Hernan Aguirre-Bermeo, Giacomo Bellani, Gustavo A. Plotnikow, Emre Erbabacan, Philippe Michel, Gyorgy Frendl, Niall Ferguson, Thomas Kander, Yasuaki Ogino, Felipe Martinez, Luca Brazzi, Ewan Goligher, SILVIO A. ÑAMENDYS-SILVA, Kai Zacharowski, Lars Hedlund, Rodrigo Biondi, Dana Tomescu, Alexey Gritsan, Matteo Pozzi, Andrea Cortegiani, Serena Knowles, Candelaria De Haro, Nuttapol Rittayamai, Shailesh Bihari, Olegs Sabelnikovs, Jonathan Chelly, Riccardo Colombo, Aroa Gomez Brey, Paolo Pelosi, Marco Bezzi, Hamidreza Jammati, Vivek Kakar, Daniel McAuley, Luciano Gattinoni, Nelson Barros, Sharif Zein, Paolo FORMENTI, VINCENZO POTA, Joana Berger-Estilita, Alistair Nichol, Michele Umbrello, Martin Dres, Carlo Volta, Jean-Daniel Chiche, Ingeborg Welters, Savino Spadaro, Tamas Szakmany, Anatole Harrois, Hasan M Al-Dorzi, Sebastien Jochmans, Maurizio Fusari, Christopher Tainter, Andrea Tinnirello, Sally Humphreys, Luis Alejandro Sánchez-Hurtado, Gilda Cinnella, Damien Roux, Evgeny Grigoryev, Ghaleb Almekhlafi, Dorothy Breen, Alessandro Protti, Necmettin Unal, Alejandro Bruhn, Ednan Bajwa, Rola Jaafar, Artigas Antonio, Ceri Battle, Christina Whitehead, Anil Hormis, Jon Laake, Serge Heines, Nora Di Tomasso, Guillermo M. Albaiceta, Raúl De Pablo Sánchez, Nicolas TERZI, Marcus Schultz, and Giovanna Occhipinti
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Mechanical ventilation ,Pediatrics ,medicine.medical_specialty ,ARDS ,Lung ,business.industry ,medicine.medical_treatment ,030208 emergency & critical care medicine ,Acute respiratory distress ,medicine.disease ,03 medical and health sciences ,0302 clinical medicine ,Anesthesiology and Pain Medicine ,medicine.anatomical_structure ,030228 respiratory system ,Severity of illness ,Epidemiology ,medicine ,SOFA score ,Prospective cohort study ,business - Abstract
Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New Background Patients with initial mild acute respiratory distress syndrome are often underrecognized and mistakenly considered to have low disease severity and favorable outcomes. They represent a relatively poorly characterized population that was only classified as having acute respiratory distress syndrome in the most recent definition. Our primary objective was to describe the natural course and the factors associated with worsening and mortality in this population. Methods This study analyzed patients from the international prospective Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure (LUNG SAFE) who had initial mild acute respiratory distress syndrome in the first day of inclusion. This study defined three groups based on the evolution of severity in the first week: “worsening” if moderate or severe acute respiratory distress syndrome criteria were met, “persisting” if mild acute respiratory distress syndrome criteria were the most severe category, and “improving” if patients did not fulfill acute respiratory distress syndrome criteria any more from day 2. Results Among 580 patients with initial mild acute respiratory distress syndrome, 18% (103 of 580) continuously improved, 36% (210 of 580) had persisting mild acute respiratory distress syndrome, and 46% (267 of 580) worsened in the first week after acute respiratory distress syndrome onset. Global in-hospital mortality was 30% (172 of 576; specifically 10% [10 of 101], 30% [63 of 210], and 37% [99 of 265] for patients with improving, persisting, and worsening acute respiratory distress syndrome, respectively), and the median (interquartile range) duration of mechanical ventilation was 7 (4, 14) days (specifically 3 [2, 5], 7 [4, 14], and 11 [6, 18] days for patients with improving, persisting, and worsening acute respiratory distress syndrome, respectively). Admissions for trauma or pneumonia, higher nonpulmonary sequential organ failure assessment score, lower partial pressure of alveolar oxygen/fraction of inspired oxygen, and higher peak inspiratory pressure were independently associated with worsening. Conclusions Most patients with initial mild acute respiratory distress syndrome continue to fulfill acute respiratory distress syndrome criteria in the first week, and nearly half worsen in severity. Their mortality is high, particularly in patients with worsening acute respiratory distress syndrome, emphasizing the need for close attention to this patient population.
- Published
- 2019
6. Development of titania coatings on glass foams
- Author
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Boccaccini, A.R., Rossetti, M., Roether, J.A., Sharif Zein, Sharif Hussein, and Ferraris, M.
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- 2009
- Full Text
- View/download PDF
7. Latest Advances in Waste Plastic Pyrolytic Catalysis
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Sharif Zein and Osman Yusifu Yansaneh
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Process Chemistry and Technology ,Chemical Engineering (miscellaneous) ,Bioengineering - Abstract
With the increase in demand for plastic use, waste plastic (WP) management remains a challenge in the contemporary world due to the lack of sustainable efforts to tackle it. The increment in WPs is proportional to man’s demand and use of plastics, and these come along with environmental challenges. This increase in WPs, and the resulting environmental consequences are mainly due to the characteristic biodegradation properties of plastics. Landfilling, pollution, groundwater contamination, incineration, and blockage of drainages are common environmental challenges associated with WPs. The bulk of these WPs constitutes polyethene (PE), polyethene terephthalate (PET) and polystyrene (PS). Pyrolysis is an eco-friendly thermo-chemical waste plastic treatment solution for valuable product recovery, preferred over landfilling and incineration solutions. In this extensive review, a critical investigation on waste plastic catalytic pyrolysis (WPCP) is performed, including catalyst and non-catalyst applications to sustainably tackle WP management. Current catalysis techniques are revealed, and some comparisons are made where necessary. Common pyrolytic products and common shortcomings and errors related to WP catalysis were also identified. The benefits of catalysts and their applications to augment and optimise thermal pyrolysis are emphasised. With all these findings, and more, this paper provides reassurance on the significance of catalysis to industrial-scale applications and products and supports related WPCP research work concerning the environment and other beneficiaries.
- Published
- 2022
8. The Effect of Catalyst Support on the Decomposition of Methane to Hydrogen and Carbon
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Sharif Hussein Sharif Zein Abdul Rahman Mohamed
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Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Decomposition of methane into carbon and hydrogen over Cu/Ni supported catalysts was investigated. The catalytic activities and the lifetimes of the catalysts were studied. Cu/Ni supported on TiO2 showed high activity and long lifetime for the reaction. Transmission electron microscopy (TEM) studies revealed the relationship between the catalyst activity and the formation of the filamentous carbon over the catalyst after methane decomposition. While different types of filamentous carbon formed on the various Cu/Ni supported catalysts, an attractive carbon nanotubes was observed in the Cu/Ni supported on TiO2. Key Words: Methane decomposition, carbon nanotube, Cu/Ni supported catalysts.
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- 2012
- Full Text
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9. The effect of catalyst calcination temperature on the diameter of carbon nanotubes synthesized by the decomposition of methane
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Chai, Siang-Piao, Sharif Zein, Sharif Hussein, and Mohamed, Abdul Rahman
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- 2007
- Full Text
- View/download PDF
10. Correction to: Potentially modifiable factors contributing to outcome from acute respiratory distress syndrome: the LUNG SAFE study
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Gerard Curley, Lorenzo Schiavoni, Giacomo Monti, Hernan Aguirre-Bermeo, Giacomo Bellani, John Laffey, Gustavo A. Plotnikow, Maria Manuela Pintado, Michael Lanspa, Emre Erbabacan, Gyorgy Frendl, Niall Ferguson, Thomas Kander, Yasuaki Ogino, Luca Brazzi, Ewan Goligher, SILVIO A. ÑAMENDYS-SILVA, Kai Zacharowski, Lars Hedlund, Dana Tomescu, Alexey Gritsan, Matteo Pozzi, Andrea Cortegiani, Candelaria De Haro, Nuttapol Rittayamai, Shailesh Bihari, Olegs Sabelnikovs, Jonathan Chelly, Riccardo Colombo, Fabiana Madotto, Sara Conti, NICOLAS NIN, Pierre-Eric DANIN, Marco Bezzi, Hamidreza Jammati, Vivek Kakar, Daniel McAuley, Frank M.P. Van Haren, Luciano Gattinoni, Kelvin Davies, Nelson Barros, Sharif Zein, Paolo FORMENTI, VINCENZO POTA, Andrea Coppadoro, Joana Berger-Estilita, Alistair Nichol, Michele Umbrello, Martin Dres, Carlo Volta, Ingeborg Welters, Savino Spadaro, Tamas Szakmany, Anatole Harrois, Hasan M Al-Dorzi, Sebastien Jochmans, Maurizio Fusari, Christopher Tainter, Tài PHAM, Andrea Tinnirello, Kenichi Nitta, Luis Alejandro Sánchez-Hurtado, Gilda Cinnella, Damien Roux, Evgeny Grigoryev, Luca MONTINI, Ghaleb Almekhlafi, Dorothy Breen, Alessandro Protti, Necmettin Unal, Alejandro Bruhn, Ednan Bajwa, Samuel Brown, Rola Jaafar, Artigas Antonio, Ceri Battle, Guillaume Carteaux, Christina Whitehead, Nicholas Mohr, Jon Laake, Serge Heines, Nora Di Tomasso, Guillermo M. Albaiceta, Raúl De Pablo Sánchez, Nicolas TERZI, Jan Máca, and Giovanna Occhipinti
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medicine.medical_specialty ,Lung ,medicine.anatomical_structure ,business.industry ,Anesthesiology ,medicine ,MEDLINE ,Acute respiratory distress ,Critical Care and Intensive Care Medicine ,Intensive care medicine ,business - Abstract
The members of the LUNG SAFE Investigators and the ESICM Trials Group were provided in such a way that they could not be indexed as collaborators on PubMed. The publisher apologizes for this error.
- Published
- 2017
11. Access policy on English language education at the primary school level in the ASEAN Plus Three member states: motivations, challenges and future directions
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Sharif Zein and Subhan Zein
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060201 languages & linguistics ,Competition (economics) ,Linguistics and Language ,Political science ,Member states ,0602 languages and literature ,Pedagogy ,06 humanities and the arts ,English language ,School level ,Language acquisition ,Language and Linguistics - Abstract
With English becoming increasingly important for achieving success in twenty-first-century global competition, policies to introduce the language to primary school children have proliferated in Asi...
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- 2017
12. To postpone or not to postpone? Examining access policy on early foreign language learning from second language acquisition and language planning and policy perspectives
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Sharif Zein and Subhan Zein
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060201 languages & linguistics ,Linguistics and Language ,Foreign language learning ,05 social sciences ,050301 education ,ComputingMilieux_LEGALASPECTSOFCOMPUTING ,06 humanities and the arts ,Second-language acquisition ,Language and Linguistics ,Linguistics ,Language planning ,0602 languages and literature ,Psychology ,0503 education - Abstract
This paper examines the suggestion to postpone instruction on early foreign language learning, from both second language acquisition (SLA) and language planning and policy (LPP) perspectives. Contrary to the widely held belief that SLA research on age effects can inform policymakers as to when to start instruction, this paper demonstrates that such research may not offer much to language policymaking. The paper argues that the use of a more pragmatic approach in the transdisciplinarity of SLA and LPP emphasizing research into the benefits of instruction for children should be the underpinning SLA-based rationale for early foreign language learning policies. The paper contends that collaborative work between policymakers and researchers working in LPP and/or SLA domains in an SLA-LPP consortium could help address the problems occurring in the micro-context of policy interpretation and enactment with a primary focus oninput enhancementrather thanpostponement.
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- 2017
13. Early Language Learning and Teacher Education
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Susan Garton, Nettie Boivin, Yuefeng, Ellen ZHANG, and Sharif Zein
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Pre service ,Learning to teach ,Mathematics education ,English language ,Psychology - Published
- 2019
14. Classroom management for teaching English to young learners
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Sharif Zein
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Classroom management ,Student achievement ,Teaching english ,ComputingMilieux_COMPUTERSANDEDUCATION ,Psychological intervention ,Young learners ,Mathematics education ,Language education ,Mainstream ,Behavioural intervention ,Psychology ,ComputingMilieux_MISCELLANEOUS - Abstract
Classroom management has been suggested as the single variable with the strongest impact on student achievement, and it has positive correlations with student participation, learning satisfaction and dropout prevention (Evertson 2013; Evertson and Weinstein 2006; Marzano and Marzano 2003). This chapter discusses effective classroom management in the English for Young Learners (EYL) classroom. It demonstrates how the bulk of research on classroom management has been primarily drawn from Western classrooms where language education is not necessarily the focus. This chapter attempts to address this issue by bringing what the mainstream classroom management research has to offer to the EYL classroom. The chapter argues for a shift in EYL classroom management from a classroom-level approach to a whole school-level approach that makes young learner behaviour management a school-wide concern. Holistic classroom-based interventions prescribed by a whole school approach such as School-Wide Positive Behavioural Interventions and Supports (SWPBIS) may help reduce classroom disruptions to be minimal while increasing learners’ self-regulation, characterising Western methodologies that are widely implemented in EYL classrooms worldwide.
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- 2018
15. Professional development needs of primary EFL teachers: perspectives of teachers and teacher educators
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Sharif Zein and Subhan Zein
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060201 languages & linguistics ,Semi-structured interview ,business.industry ,Teaching method ,05 social sciences ,Professional development ,Primary education ,050301 education ,English as a foreign language ,06 humanities and the arts ,Grounded theory ,Education ,0602 languages and literature ,Pedagogy ,Mathematics education ,Medicine ,Language proficiency ,Faculty development ,business ,0503 education - Abstract
This study investigates the professional development (PD) needs of primary English as a foreign language (EFL) teachers whose professional field has received significant interest at the global level in the past two decades. The study takes a different stance from previous research that exclusively generated data from teachers because it sought the perspectives of teacher educators as well. The decision to include teacher educators in this study has proven useful to generate ample data that suggest the inseparable relationships between primary EFL teachers’ profiles, their needs and the specific typicality of their professional environment. The study proposes a model of needs-based PD for primary EFL teachers that exemplifies these aspects. The discussion in the study brings implications for future research into the PD needs of primary EFL teachers. It will also inform teacher educators and educational policy-makers to develop a framework of reference for the design of PD programmes that well attend to pri...
- Published
- 2016
16. Preparing Asian English teachers in the global world
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Sharif Zein
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Structure (mathematical logic) ,Teacher preparation ,Edited volume ,media_common.quotation_subject ,Mathematics education ,Quality (business) ,Sociology ,media_common - Abstract
This chapter provides an overview of this edited volume while outlining the motivations underlying its development. The chapter highlights key themes that characterise English teacher preparation in Asia in the global world. This chapter shows how the chapters in this edited volume attempt to develop quality teacher preparation for English teachers in Asia through in-depth discussions of their distinctive topics. The aggregate of all the chapters in the volume points to the idea that the work of pre-service teacher preparation in the global world is beyond the transmission of teaching strategies, or things that can be used in the classroom. Rather, effective English teacher preparation generates more practical elements, deeper theory, richer reflection and integration of teacher preparation components. Finally, the chapter outlines the structure of the volume, summarising each individual chapter contained in this volume.
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- 2018
17. English Language Teacher Preparation in Asia
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FATIHA SENOM, Ishamina Athirah Gardiner, Mai Trang Vu, Sharif Zein, and Miyoko Takatama
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Teacher preparation ,Political science ,Pedagogy ,English language - Published
- 2018
18. Influence of Solvent Exchange Drying Method on Mixed Matrix Membrane for Gas Separation
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Zeinab Abbas Jawad, Sharif Hussein Sharif Zein, Siew Chun Low, and Abdul Latif Ahmad
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chemistry.chemical_classification ,Materials science ,Polymer ,Carbon nanotube ,Permeance ,Cellulose acetate ,law.invention ,Membrane technology ,chemistry.chemical_compound ,Membrane ,chemistry ,Chemical engineering ,law ,Gas separation ,Phase inversion - Abstract
The improvement of the CO2 separation efficiency from flue gases has been identified as a high-priority research area, to reduce the total energy cost of sequestration technologies in coal-fired power plant. Among the separationtechniques, membrane technology, in particular mixed matrix membrane (MMM) appeared as the most attractive module due to its high separation capabilities (inorganic fillers) and economical processing materials (polymeric membrane). In this study, MMM was synthesized from cellulose acetate polymer with functionalized multi walled carbon nanotubes served as the inorganic fillers by wet phase inversion. Both vacuum drying and ethanol-hexane exchange drying methods were compared to investigate their influence on the MMM morphologies and properties. Experimental findings (FESEM, AFM and ATR-FTIR) showed that the ethanol–hexane exchange drying was an appropriate method to minimize morphology change of MMM, whereas the vacuum drying caused the greatestshrinkage to MMM structure. The CO2 permeance results supported the proposed solvent exchange mechanism where MMM with solvent exchange drying showed to have improved in their mechanical strength and betterpermeance of (733.90-741.67) GPU compared to the vacuum drying (18.72-18.44) GPU within pressure range of 1 to 3 bars.
- Published
- 2017
19. Factors affecting the professional development of elementary English teachers
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Sharif Zein and Subhan Zein
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060201 languages & linguistics ,Semi-structured interview ,Medical education ,media_common.quotation_subject ,05 social sciences ,Professional development ,050301 education ,Economic shortage ,06 humanities and the arts ,Education ,Intrusion ,Teacher preparation ,0602 languages and literature ,Pedagogy ,Quality (business) ,Faculty development ,Empowerment ,Psychology ,0503 education ,media_common - Abstract
The poor classroom practices of English teachers at elementary level in Indonesia have been attributed to the inadequacy of pre-service education. Yet, whether in-service professional development (PD) also plays a role is unknown. This study investigated the perspectives of 23 teachers, 14 teacher educators and 3 school principals regarding the efficacy of in-service PD in preparing elementary English teachers. The results demonstrate that the shortage of quality teacher educators contributed to the inadequacy of in-service PD. While this study calls for more systematic efforts to tackle the shortage of quality teacher educators, it also highlights the needs for PD of teacher educators. Furthermore, the intrusion of educational administrators adversely affected the design and administration of teacher preparation programs, resulting in the poor training management and the ambiguous selection of training participants. The study further asserts the necessity for empowerment of teacher educators in order to ...
- Published
- 2015
20. Influence of solvent exchange time on mixed matrix membrane separation performance for CO2/N2 and a kinetic sorption study
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Zeinab Abbas Jawad, Thiam Leng Chew, Sharif Hussein Sharif Zein, Abdul Latif Ahmad, and Siew Chun Low
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Analytical chemistry ,Filtration and Separation ,Sorption ,Permeance ,Biochemistry ,Cellulose acetate ,Membrane technology ,Solvent ,chemistry.chemical_compound ,Membrane ,chemistry ,Chemical engineering ,General Materials Science ,Gas separation ,Physical and Theoretical Chemistry ,Solubility - Abstract
Carbon dioxide (CO2) is the largest contributor of greenhouse gas emissions. Mixed matrix membranes (MMMs) have recently received attention as an attractive candidate for membrane-based separation, for which MMMs can serve as an alternative to conventional polymeric and inorganic membranes. In this work, MMMs were developed using a cellulose acetate polymer with multi-walled carbon nanotubes. Vacuum drying and solvent-exchange drying methods were compared with different solvent exchange times (ethanol and hexane) based on the MMM morphologies and separation performances. The sorption of CO2 and the diffusion and solubility coefficients of the MMMs that were synthesized using the two drying methods mentioned above were determined kinetically. The separation results supported the effectiveness of the newly proposed solvent-exchange technique, where the MMMs that were treated with ethanol for 4 h followed by n-hexane for 1 h (M6) had greater mechanical strength and a better CO2/nitrogen (N2) separation performance at 40.17. Additionally, the kinetic results indicated that the solubility coefficient directly influenced the CO2 permeance, with the highest value of 198.352×1011 cm3(STP)/cm4 cmHg observed for the M6 membrane sample (4 h ethanol followed by 1 h n-hexane).
- Published
- 2015
21. Incorporation of Inorganic Carbon Nanotubes Fillers into the CA Polymeric Matrix for Improvement in CO2/N2 Separation
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Zeinab Abbas Jawad, Abdul Latif Ahmad, Sharif Hussein Sharif Zein, and Siew Chun Low
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Materials science ,Total inorganic carbon ,Chemical engineering ,Biomedical Engineering ,Polymeric matrix ,Pharmaceutical Science ,Medicine (miscellaneous) ,Bioengineering ,Nanotechnology ,Biotechnology - Published
- 2014
22. Facile Preparation of Co3O4 Nanoflower through Forced Hydrolysis
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Sharif Zein Sharif Hussein, Miskam Muhamad Azman, Basir Nor Irwin, and Ahmad Abdul Latif
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Hydrolysis ,Materials science ,Agglomerate ,One-Step ,Nanotechnology ,Nanorod ,General Medicine ,Nanoflower ,Cobalt oxide ,Hydrothermal circulation ,Amorphous solid - Abstract
One of the interesting structures in nanoCo3O4's preparation that have been reported fairly recent is the flower-like structure often referred as nanoflower. Several interesting applications involving Co3O4 nanoflower have also been reported. This paper present a facile approach to prepare Co3O4 nanoflower using one step forced hydrolysis technique using cobalt chloride hexahydrate as starting material as opposed to the standard two steps hydrothermal technique. The produced nanoscale Co3O4 is in agglomerate of nanorods producing a dandelion-like flower structure. The prepared Co3O4 is in hydrated and amorphous forms with a surface area of 62 m2/g and average pore size of 12 nm.
- Published
- 2014
23. Pre-service education for primary school English teachers in Indonesia: policy implications
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Sharif Zein and Subhan Zein
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060201 languages & linguistics ,Semi-structured interview ,Educational quality ,media_common.quotation_subject ,education ,Primary education ,Primary level ,06 humanities and the arts ,Grounded theory ,Education ,Pre service ,mental disorders ,0602 languages and literature ,Mathematics education ,Quality (business) ,Language teacher ,Psychology ,media_common - Abstract
Although English is only an extra-curricular subject at primary level in Indonesia, expectations over the improved quality of the teachers are exceptionally high . This is the case in the past few years in which the low proficiency of primary English teachers and their lack of teaching competencies have repeatedly been pointed out as major constraints. Unfortunately, it remains unclear whether this problem is attributed to the delivery of pre-service education in preparing primary school English teachers. This paper gathered data from teachers, language teacher educators, primary school principals, members of educational boards, and educational consultants. The data were analysed using Grounded Theory in order to examine the adequacy of pre-service education in Indonesia to prepare primary school English teachers as well as factors that contribute to its efficacy or lack thereof. The findings of the study demonstrate the need for specific preparation for primary school English teachers as well as further ...
- Published
- 2014
24. A cellulose acetate/multi-walled carbon nanotube mixed matrix membrane for CO2/N2 separation
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Abdul Latif Ahmad, Zeinab Abbas Jawad, Siew Chun Low, and Sharif Hussein Sharif Zein
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chemistry.chemical_classification ,Materials science ,Filtration and Separation ,Nanotechnology ,Carbon nanotube ,Permeance ,Polymer ,Permeation ,Biochemistry ,Cellulose acetate ,law.invention ,chemistry.chemical_compound ,Membrane ,chemistry ,Chemical engineering ,law ,General Materials Science ,Gas separation ,Physical and Theoretical Chemistry ,Phase inversion - Abstract
Carbon dioxide (CO2) emissions have been rising indiscriminately and are becoming a major contributor to Earth's greenhouse effect. One of the most promising means of separating the hazardous CO2 gas is to develop a cost effective and high-performance CO2 separation membrane. From the wide range of membrane materials available, mixed matrix membrane (MMM) technology has shown the most promising results. In this study, MMMs were synthesized from cellulose acetate (CA) with multi-walled carbon nanotubes (MWCNTs) using the wet phase inversion technique. The results shown that MMMs with functionalized MWCNTs (MWCNTs-F) demonstrated the enhance permeance and selectivity towards the separation of CO2/nitrogen (N2). Thus, different loadings of MWCNTs-F into MMM were further investigated to interpret the physical morphologies and functionalities of MMMs, which enable the separation of CO2/N2 in a specific manner. Gas permeation measurements showed excellent MMM performances in terms of permeance and selectivity at 0.1 wt% loadings of MWCNTs-F. This superior performance was due to the homogeneous dispersion between the MWCNTs-F and the CA matrix, which increased the sufficient free volumes between the polymer chains and enlarged the polymer/nanofiller interface, as confirmed by the X-ray diffraction results.
- Published
- 2014
25. Green tea polyphenol–reduced graphene oxide: derivatisation, reduction efficiency, reduction mechanism and cytotoxicity
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Sharif Hussein Sharif Zein, Ridzuan Zakaria, and Muhammad Faiq Abdullah
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Thermogravimetric analysis ,GTP' ,Reducing agent ,Graphene ,General Chemical Engineering ,Analytical chemistry ,Oxide ,General Chemistry ,law.invention ,chemistry.chemical_compound ,X-ray photoelectron spectroscopy ,chemistry ,law ,Zeta potential ,Fourier transform infrared spectroscopy ,Nuclear chemistry - Abstract
This paper reports on the derivatisation, reduction efficiency, reduction mechanism and cytotoxicity of green tea polyphenol–reduced graphene oxide (GTP–RGO). The reduction of graphene oxide (GO) at 90 °C using a weight ratio (WR) of GTP/GO = 1 resulted in the production of a stable GTP–RGO dispersion in aqueous media, as indicated by the results of ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and the measurement of zeta potential and electrophoretic mobility. In addition, the results from UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis indicated the comparable reduction ability of GTP relative to the standard reducing agent, hydrazine (N2H4). The removal mechanism of epoxy groups from GO via reduction reaction with GTP was investigated by implementing the hybrid functional method of Becke-3-parameters-Lee–Yang–Parr (B3LYP) using Gaussian 09 software. The energy and frequency calculations showed that the GO reduction using GTP was more spontaneous and took place relatively faster than the reduction using N2H4, as evidenced by a higher entropy change (ΔS) (0.039 kcal mol−1 K−1) and lower Gibbs free energy (ΔG) barrier (58.880 kcal mol−1). The cytotoxicities of the GO and GTP–RGO samples were evaluated against human colonic fibroblast cells (CCD-18Co). The GO sample was determined to be toxic even at low concentration (6.25 μg mL−1), while the GTP–RGO sample possesses notably low toxicity at the same concentration. The cell culture experiments revealed that the incorporation of GTP led to a decrease in the toxicity of GTP–RGO samples.
- Published
- 2014
26. Cytocompatibility and Mechanical Properties of Hydroxyapatite Composite Reinforced with Multi-Walled Carbon Nanotubes and Bovine Serum Albumin
- Author
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Soon Huat Tan, Suzylawati Ismail, Sharif Hussein Sharif Zein, and Fatemeh Gholami
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Materials science ,biology ,High cell ,General Medicine ,Carbon nanotube ,law.invention ,Trabecular bone ,Compressive strength ,law ,Cell toxicity ,Biological property ,Hydroxyapatite composite ,biology.protein ,Bovine serum albumin ,Composite material - Abstract
In this study, HA/MWCNTs/BSA composites with highly improved mechanical properties for use as bone replacement materials were developed. The HA/MWCNTs/BSA composites powders with different types of MWCNTs (MWCNTs-OH, MWCNTs) were successfully prepared. Compressive strength tests and cell toxicity test on human fibroblasts cell lines (CCD-18Co) were performed to evaluate the mechanical and biological properties of the developed composites. The results show that the HA composites which are prepared using MWCNTs-OH and BSA with compressive strength of 18.92 MPa has the highest results in comparison with HA composites which are prepared using non-functionalized MWCNTs. The obtained compressive strength is higher than values that reported for the strength of trabecular bone (2-12 MPa). Cell culture experiments showed that at low concentrations (6.25 and 12.5 mg/ml), HA/MWCNT/BSA composites led to cell proliferative rather than cytotoxic effects on fibroblasts, evidenced by high cell viability of approximately 250%.
- Published
- 2013
27. The electrochemical studies of the corrosion resistance behaviour of hydroxyapatite coatings on stainless steel fabricated by electrophoretic deposition
- Author
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Kean-Khoon Chew, David S. McPhail, Abdul Latif Ahmad, Sharif Hussein Sharif Zein, and Muhammad Faiq Abdullah
- Subjects
Electrophoretic deposition ,Materials science ,Ha coating ,Open-circuit voltage ,General Chemical Engineering ,Metallurgy ,Pitting corrosion ,Hydroxyapatite coating ,Composite material ,Electrochemistry ,Capacitance ,Corrosion - Abstract
HA was coated on stainless steel (SS) 316L by using electrophoretic deposition to impart corrosion resistance upon SS 316L. Consequently, corrosion behaviour of HA coated SS 316L deposited from applied voltages 10 V to 60 V (denoted as HA/SS316L-10V until -60V) was evaluated in comparison with pristine SS 316L by various electrochemical studies. As results, linear potentiodynamic polarisation result suggested that HA/SS316L-40V exhibits highest open circuit potential indicating that successful protection of HA coating. Additionally, cyclic polarisation studies revealed that HA coated SS 316L improves pitting corrosion resistance. Finally, EIS results demonstrated that higher polarisation resistance and lower capacitance values for HA/SS316L-40V.
- Published
- 2013
28. Cytocompatibility, bioactivity and mechanical strength of calcium phosphate cement reinforced with multi-walled carbon nanotubes and bovine serum albumin
- Author
-
LC Lutz-Christian Gerhardt, Sharif Hussein Sharif Zein, Soon Huat Tan, David S. McPhail, Fatemeh Gholami, Kah Ling Low, Liam M. Grover, and Aldo R. Boccaccini
- Subjects
Materials science ,Scanning electron microscope ,Simulated body fluid ,chemistry.chemical_element ,macromolecular substances ,Carbon nanotube ,Calcium ,Apatite ,law.invention ,law ,Materials Chemistry ,Bovine serum albumin ,Composite material ,Fourier transform infrared spectroscopy ,biology ,Process Chemistry and Technology ,technology, industry, and agriculture ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Compressive strength ,chemistry ,visual_art ,Ceramics and Composites ,biology.protein ,visual_art.visual_art_medium ,Nuclear chemistry - Abstract
This paper reports on the in vitro cytotoxicity, bioactivity behaviour and mechanical properties of novel injectable calcium phosphate cement filled with hydroxylated multi-walled carbon nanotubes and bovine serum albumin (CPC/MWCNT-OH/BSA). To predict the in vitro bioactivity of the calcium phosphate composites, we investigated apatite formation on CPC/MWCNT-OH/BSA composites after soaking in simulated body fluid (SBF) for up to 28 days. Compressive strength tests, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and cell culture experiments with human CCD-18Co fibroblasts cell lines were performed to evaluate the effect of SBF pre-treatment on the mechanical, structural and biological properties of the CPC/MWCNT-OH/BSA composites. Although apatite formation increased significantly with SBF immersion period, the results showed that all soaked CPC/MWCNT-OH/BSA composites exhibited up to 2.5 times lower compressive strength (13–20 MPa), which were however higher than values reported for the strength of trabecular bone (2–12 MPa). Cell culture experiments showed that low concentrations (6.25 and 12.5 μg/ml) of bio-mineralised CPC/MWCNT-OH/BSA composites led to cell proliferative rather than cytotoxic effects on fibroblasts, evidenced by high cell viabilities (104–113%). The novel CPC/MWCNT-OH/BSA composites presented in this study showed favourable cytocompatible and bioactive behaviour along with high compressive strength (13–32 MPa) and are therefore considered as an attractive bone filling material.
- Published
- 2013
29. Facile Synthesis of Silver Nanoparticles by Chemical Reduction Route
- Author
-
Zulkifli Ahmad, Sharif Zein Sharif Hussein, M. Mariatti, and Rajasingam Ratnamalar
- Subjects
Materials science ,Chemical engineering ,Mechanics of Materials ,Reducing agent ,Mechanical Engineering ,Inorganic chemistry ,Chemical reduction ,General Materials Science ,Ag nanoparticles ,Condensed Matter Physics ,Spectroscopy ,Silver nanoparticle - Abstract
This work reports a simple chemical reduction route for the preparation of uniformed Ag nanoparticles whereby a fine control over the sizes of the Ag nanoparticles was studied by varying the concentrations of the reducing agents used. In characterization, UV-Vis spectroscopy showed the changes in optical properties of the Ag nanoparticles with regards to their sizes, where as the XRD patterns of the synthesized Ag nanoparticles confirmed the distinct peaks approximately at 2θ = 38.1°, 44.3°, 64.4°, 77.4°, and 81.5 representing Bragg’s reflections from (111), (200), (220), (311), and (222) planes of the face centred cubic lattice phase. This route of synthesis is feasible to produce Ag nanoparticles with diameters in the range of 30-45 nm.
- Published
- 2013
30. The Functionalization of Beta-Cyclodextrins on Multi Walled Carbon Nanotubes: Effects of the Dispersant and Non Aqueous Media
- Author
-
Sharif Hussein Sharif Zein, Siew Chun Low, Abdul Latif Ahmad, and Zeinab Abbas Jawad
- Subjects
Aqueous medium ,Chemistry ,Biomedical Engineering ,Pharmaceutical Science ,Medicine (miscellaneous) ,Beta-Cyclodextrins ,Bioengineering ,Carbon nanotube ,Dispersant ,law.invention ,Chemical engineering ,law ,Surface modification ,Biotechnology - Published
- 2013
31. Hydroxyapatite nanoparticles: Electrospinning and calcination of hydroxyapatite/polyvinyl butyral nanofibers and growth kinetics
- Author
-
Siti Maisurah Zakaria, John A. Jansen, Sharif Hussein Sharif Zein, and Mohd Roslee Othman
- Subjects
Hot Temperature ,Materials science ,Light ,Nanofibers ,Biomedical Engineering ,Nanoparticle ,law.invention ,Biomaterials ,Surface-Active Agents ,chemistry.chemical_compound ,Polyvinyl butyral ,Microscopy, Electron, Transmission ,law ,Spectroscopy, Fourier Transform Infrared ,Electrochemistry ,Scattering, Radiation ,Calcination ,Fiber ,Particle Size ,Sodium dodecyl sulfate ,Composite material ,Metals and Alloys ,Sodium Dodecyl Sulfate ,Tissue engineering and pathology [NCMLS 3] ,Electrospinning ,Body Fluids ,Kinetics ,Durapatite ,chemistry ,Chemical engineering ,Nanofiber ,Microscopy, Electron, Scanning ,Ceramics and Composites ,Nanoparticles ,Indicators and Reagents ,Polyvinyls ,Spectrophotometry, Ultraviolet ,Particle size ,Crystallization ,Algorithms - Abstract
Item does not contain fulltext Electrospinning of hydroxyapatite (HA)/polyvinyl butyral solution resulted in the formation of fibers with average diameter of 937-1440 nm. These fibers were converted into HA nanoparticles with size
- Published
- 2012
32. Investigation of the chemocatalytic and biocatalytic valorization of a range of different lignin preparations: the importance of β-O-4 content
- Author
-
Timothy D. H. Bugg, Nicholas J. Westwood, Jaime Rodríguez, Jason P. Hallett, Florent P. Bouxin, Christopher S. Lancefield, Goran M. M. Rashid, Agata Wasak, S. David Jackson, Wei-Chien Tu, Sharif Hussein Sharif Zein, University of St Andrews. School of Chemistry, University of St Andrews. EaSTCHEM, and University of St Andrews. Biomedical Sciences Research Complex
- Subjects
TP ,General Chemical Engineering ,Organosolv ,NDAS ,Pseudomonas fluorescens ,Superoxide dismutase ,010402 general chemistry ,01 natural sciences ,Syringaldehyde ,Catalysis ,Dyp peroxidase ,Lignin valorization ,chemistry.chemical_compound ,Biotransformation ,Environmental Chemistry ,Lignin ,Organic chemistry ,Catalytic hydrogenation ,Microbial biotransformation ,QD ,biology ,010405 organic chemistry ,Renewable Energy, Sustainability and the Environment ,General Chemistry ,biology.organism_classification ,QD Chemistry ,0104 chemical sciences ,chemistry ,Ionic liquid ,Rhodococcus jostii RHA1 ,Kraft paper - Abstract
This project was supported by a grant from the Lignocellulosic Biorefinery Network, a BBSRC-funded network in Biotechnology and Bioenergy. A set of seven different lignin preparations was generated from a range of organosolv (acidic, alkaline, ammonia-treated and dioxane-based), ionic liquid, autohydrolysis and Kraft pretreatments of lignocelluloses. Each lignin was characterised by 2D HSQC NMR spectroscopy, showing significant variability in the β-O-4 content of the different lignin samples. Each lignin was then valorised using three biocatalytic methods (microbial biotransformation with Rhodococcus jostii RHA045, treatment with Pseudomonas fluorescens Dyp1B or Sphingobacterium sp. T2 manganese superoxide dismutase) and two chemocatalytic methods (catalytic hydrogenation using Pt/alumina catalyst, DDQ benzylic oxidation/Zn reduction). Highest product yields for DDQ/Zn valorisation were observed from poplar ammonia percolation-organosolv lignin, which had the highest β-O-4 content of the investigated lignins and also gave the highest yield of syringaldehyde (243 mg L-1) when using R. jostii RHA045, and the most enzymatic products using P. fluorescens Dyp1B. The highest product yield from the Pt/alumina hydrogenation was observed using oak dioxasolv lignin, which also had a high β-O-4 content. In general, highest product yields for both chemocatalytic and biocatalytic valorisation methods were obtained from preparations that showed highest β-O-4 content, while variable yields were obtained with preparations containing intermediate β-O-4 content, and little or no product was obtained with preparations containing low β-O-4 content. Postprint
- Published
- 2016
33. Investigation into the role of NaOH and calcium ions in the synthesis of calcium phosphate nanoshells
- Author
-
Sharif Hussein Sharif Zein, C. H. Yeo, David S. McPhail, and Abdul Latif Ahmad
- Subjects
chemistry.chemical_classification ,calcium ions ,Base (chemistry) ,NaOH ,General Chemical Engineering ,Nanoshells ,Inorganic chemistry ,chemistry.chemical_element ,lcsh:TP155-156 ,Calcium ,chemistry.chemical_compound ,chemistry ,Dynamic light scattering ,Calcium phosphate ,Sodium hydroxide ,Liposomes ,Zeta potential ,Titration ,Particle size ,Fourier transform infrared spectroscopy ,lcsh:Chemical engineering - Abstract
Calcium phosphate (CaP) nanoshells were prepared using negatively charged liposomes (1,2-dioleoyl-sn-glycero-3-phosphate sodium salt (DOPA)) as a template by base titration synthesis at various concentrations of NaOH and calcium ions. The elemental composition, morphology, particle size, particle size distribution and zeta potential of the products were determined via various characterisation techniques, such as energy-dispersive X-ray spectrometry (EDX), transmission electron microscopy (TEM), dynamic light scattering (DLS), laser Doppler velocimetry (LDV) and Fourier transform infrared spectroscopy (FTIR). The best results showed that stable spherical CaP nanoshells with a mean particle size of 197.5 ± 5.8 nm and a zeta potential of -34.5 ± 0.6 mV were successfully formed when 0.100 M sodium hydroxide (NaOH) and 0.100 M calcium ions were used. Moreover, an optimal pH of 10.52 and a final Ca/P molar ratio of 0.97 were achieved under these conditions.
- Published
- 2012
34. Corrosion Resistance Study of Electrophoretic Deposited Hydroxyapatite on Stainless Steel for Implant Applications
- Author
-
Aldo R. Boccaccini, Ahmad Abdul Latif, Sharif Zein Sharif Hussein, David S. McPhail, and Kean Khoon Chew
- Subjects
Aqueous solution ,Materials science ,Biocompatibility ,Mechanical Engineering ,Metallurgy ,Electrochemistry ,Corrosion ,Electrophoresis ,Electrophoretic deposition ,Mechanics of Materials ,General Materials Science ,Implant ,Composite material ,Deposition (law) - Abstract
Stainless steel (SS) is often used for orthopaedic and dental implants because of its excellent mechanical characteristics. However, from an electrochemical perspective, SS can be susceptible to corrosion-related problems. Inorganic bioactive coatings on SS surfaces are reported to impart corrosion resistance and enhance biocompatibility. In this paper, hydroxyapatite (HA) coatings were developed on SS 316L by an electrophoretic deposition (EPD) technique at applied deposition voltages from 10 to 60 V in an acidic aqueous solution. The present study was performed to optimise the applied voltage required to produce stable HA coatings on SS 316L. Their corrosion resistance in simulated body conditions were investigated using the potentiodynamic polarisation curves. The results of the electrochemical studies revealed that the optimal applied voltage for EPD of HA on SS 316L was 40 V. The polarisation parameters, such as the corrosion potential, breakdown potential and repassivation potential of HA coated materials demonstrated nobler behaviours than the uncoated SS 316L. These results validated the successful formation of stable and protective HA coatings on SS 316L.
- Published
- 2012
35. Energy and environmental applications of carbon nanotubes
- Author
-
Abdul Rahman Mohamed, Soon Huat Tan, Yit Thai Ong, Sharif Hussein Sharif Zein, Chin Wei Tan, and Kok Hong Tan
- Subjects
Nanocomposite ,Materials science ,business.industry ,Fossil fuel ,Energy conversion efficiency ,Nanotechnology ,Environmental pollution ,Carbon nanotube ,Environmentally friendly ,law.invention ,Hydrogen storage ,law ,Environmental Chemistry ,Energy transformation ,business - Abstract
Energy and environment are major global issues inducing environmental pollution problems. Energy generation from conventional fossil fuels has been identified as the main culprit of environmental quality degradation and environmental pollution. In order to address these issues, nanotechnology plays an essential role in revolutionizing the device applications for energy conversion and storage, environmental monitoring, as well as green engineering of environmental friendly materials. Carbon nanotubes and their hybrid nanocomposites have received immense research attention for their potential applications in various fields due to their unique structural, electronic and mechanical properties. Here, we review the applications of carbon nanotubes (1) in energy conversion and storage such as in solar cells, fuel cells, hydrogen storage, lithium ion batteries and electrochemical supercapacitors, (2) in environmental monitoring and wastewater treatment for the detection and removal of gas pollutants, pathogens, dyes, heavy metals and pesticides and (3) in green nanocomposite design. Integration of carbon nanotubes in solar and fuel cells has increased the energy conversion efficiency of these energy conversion applications, which serve as the future sustainable energy sources. Carbon nanotubes doped with metal hydrides show high hydrogen storage capacity of around 6 wt% as a potential hydrogen storage medium. Carbon nanotubes nanocomposites have exhibited high energy capacity in lithium ion batteries and high specific capacitance in electrochemical supercapacitors, in addition to excellent cycle stability. High sensitivity and selectivity towards the detection of environmental pollutants are demonstrated by carbon nanotubes based sensors, as well as the anticipated potentials of carbon nanotubes as adsorbent to remove environmental pollutants, which show high adsorption capacity and good regeneration capability. Carbon nanotubes are employed as reinforcement material in green nanocomposites, which is advantageous in supplying the desired properties, in addition to the biodegradability. This article presents an overview of the advantages imparted by carbon nanotubes in electrochemical devices of energy applications and green nanocomposites, as well as nanosensor and adsorbent for environmental protection.
- Published
- 2012
36. Preparation of Perovskite Titania Ceramic Membrane by Sol‐Gel Method
- Author
-
Sani N. A. Abdullah, Abdul Latif Ahmad, and Sharif Hussein Sharif Zein
- Subjects
Ceramic membrane ,Materials science ,Chromatography ,Chemical engineering ,Separation technology ,Perovskite (structure) ,Sol-gel - Published
- 2012
37. The corrosion scenario in human body: Stainless steel 316L orthopaedic implants
- Author
-
Sharif Hussein Sharif Zein, Kean-Khoon Chew, and Abdul Latif Ahmad
- Subjects
business.industry ,Osteoporosis ,Metallurgy ,Early recovery ,Total Joint Replacements ,Dentistry ,medicine.disease ,Orthopaedic implant ,Corrosion ,Corrosion testing ,Long period ,medicine ,Implant ,business - Abstract
As the world’s populations increase and age, there is a parallel increase in the number of medical procedures addressed to bone related injuries. It is estimated that approximately 1 million of orthopaedic implant surgeries in association with total joint replacements are needed every year. This number is expected to double between 1999 and 2025 as a result of increasing numbers of musculoskeletal injuries (i.e., due to routine activities such as work, sport, etc.) and musculoskeletal diseases (i.e., such as osteoporosis, arthritis and bursitis due to increase age). Consequently, the increase demand for better quality of life has necessarily led people to opt for high quality orthopaedic devices for early recovery and speedy resumption of their routine activities. Unfortunately in the present time, it has been found that the current used orthopaedic implants have the tendencies to fail after long period of usage, due to the corrosion issue of implant in the human body. Therefore, this paper provides a simple overview about the corrosion issue of stainless steel (SS) 316L as implants in human body. Electrophoretic deposition (EPD) of hydroxypaptite (HA) bioceramic was proposed as the approach to minimize the corrosion phenomena. Additionally, the corrosion testing of HA coated SS 316L in comparison to pristine SS 316L was also performed and discussed.
- Published
- 2012
38. Comparison of DOPA and DPPA liposome templates for the synthesis of calcium phosphate nanoshells
- Author
-
David S. McPhail, Abdul Latif Ahmad, Chiew-Hwee Yeo, and Sharif Hussein Sharif Zein
- Subjects
Liposome ,Morphology (linguistics) ,Stereochemistry ,Process Chemistry and Technology ,chemistry.chemical_element ,Calcium ,Phosphate ,Nanoshell ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,Template ,chemistry ,Chemical engineering ,Materials Chemistry ,Ceramics and Composites ,Zeta potential ,Particle size - Abstract
The aim of this paper is to synthesise calcium phosphate (CaP) nanoshells by controlling their particle size and shape using negatively charged liposomes (1,2 dioleoyl-sn-glycero-3 phosphate sodium salt (DOPA) and 1,2-dipalmitoyl-sn-glycero-3-phosphate sodium salt (DPPA)) as a template. The morphology, particle size, size distribution and zeta potential properties of DOPA and DPPA liposome templates were determined. The results showed that both DOPA and DPPA formed spherical nanoshell structures to be used as templates for the synthesis of CaP nanoshells. By using the DOPA template, spherical CaPs structures with a mean particle size of 197.5 ± 5.8 nm were successfully formed. In contrast, needle or irregularly shaped CaP particles were observed when using the DPPA template.
- Published
- 2012
39. Synthesis of a TiO2 ceramic membrane containing SrCo0.8Fe0.2O3 by the sol–gel method with a wet impregnation process for O2 and N2 permeation
- Author
-
Abdul Latif Ahmad, Nur Aimie Abdullah Sani, and Sharif Hussein Sharif Zein
- Subjects
Materials science ,Hydroxypropyl cellulose ,Process Chemistry and Technology ,Analytical chemistry ,Permeation ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,law.invention ,chemistry.chemical_compound ,Ceramic membrane ,Membrane ,chemistry ,Chemical engineering ,law ,Alkoxide ,Materials Chemistry ,Ceramics and Composites ,Calcination ,Fourier transform infrared spectroscopy ,Sol-gel - Abstract
A SrCo0.8Fe0.2O3 impregnated TiO2 membrane (TiO2–SrCo0.8Fe0.2O3 membrane) was successfully prepared using a sol–gel method in combination with a wet impregnation process. The membrane was subjected to a single gas permeance test using oxygen (O2) and nitrogen (N2). The TiO2 membrane was immersed in the SrCo0.8Fe0.2O3 solution, dried and then calcined to affix SrCo0.8Fe0.2O3 into the membrane. The effect of the acid/alkoxide (H+/Ti4+) molar ratio of the TiO2 sol on the TiO2 phase transformation was investigated. The optimal molar ratio was found to be 0.5, which resulted in nanoparticles with a mean size of 5.30 nm after calcination at 400 °C. The effect of calcination temperature on the phase transformation of TiO2 and SrCo0.8Fe0.2O3 was investigated by varying the calcination temperature from 300 to 500 °C. X-ray diffraction spectroscopy (XRD) and Fourier transform infrared (FTIR) analysis confirmed that a calcination temperature of 400 °C was preferable for preparing a TiO2–SrCo0.8Fe0.2O3 membrane with fully crystallized anatase and SrCo0.8Fe0.2O3 phases. The results also showed that polyvinyl alcohol (PVA) and hydroxypropyl cellulose (HPC) were completely removed. Field emission scanning electron microscopy (FESEM) analysis results showed that a crack-free and relatively dense TiO2 membrane (∼0.75 μm thickness) was created with a multiple dip-coating process and calcination at 400 °C. The gas permeation results show that the TiO2 and TiO2–SrCo0.8Fe0.2O3 membranes exhibited high permeances. The TiO2–SrCo0.8Fe0.2O3 membrane developed provided greater O2/N2 selectivity compared to the TiO2 membrane alone.
- Published
- 2011
40. STRUCTURAL AND INTERACTION PROPERTIES OF ENCAPSULATED <font>MnO2</font> NANOWIRES FILLED MWCNTs
- Author
-
Saiful Izwan Abd Razak and Sharif Hussein Sharif Zein
- Subjects
Materials science ,Nanowire ,chemistry.chemical_element ,Manganese ,Carbon nanotube ,Condensed Matter Physics ,Multiwalled carbon ,law.invention ,symbols.namesake ,chemistry ,law ,symbols ,General Materials Science ,Tube (fluid conveyance) ,Composite material ,Raman spectroscopy - Abstract
Uniform encapsulated MnO2 nanowires were achieved within the cavity of multiwalled carbon nanotubes (MWCNTs). The Raman spectra revealed a charge-transfer shifts between the MnO2 particles and the inner tube of MWCNTs. Thin, uniform and continuous MnO2 was observed with a diameter of 9 nm.
- Published
- 2011
41. The effect of interfacial bonding of calcium phosphate cements containing bio-mineralized multi-walled carbon nanotube and bovine serum albumin on the mechanical properties of calcium phosphate cements
- Author
-
Soon Huat Tan, Sharif Hussein Sharif Zein, Kah Ling Low, David S. McPhail, and Aldo R. Boccaccini
- Subjects
Materials science ,biology ,Interfacial bonding ,Process Chemistry and Technology ,Composite number ,technology, industry, and agriculture ,chemistry.chemical_element ,A protein ,Crystal growth ,macromolecular substances ,Carbon nanotube ,Calcium ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,law.invention ,Compressive strength ,chemistry ,Chemical engineering ,law ,Materials Chemistry ,Ceramics and Composites ,biology.protein ,Bovine serum albumin ,Composite material - Abstract
The aim of this study was to investigate the effect of adding bio-mineralized hydroxyl functionalized multi-walled carbon nanotubes (MWCNTs–OH) on the compressive strength of calcium phosphate cements (CPCs). Bovine serum albumin (BSA) was also incorporated as a protein which acts as promoter of hydroxyapatite (HA) crystal growth when bounded to CPC granules. The results show that the strong interfacial bonding of CPC/MWCNTs–OH is essential to improve the mechanical properties of CPC/bio-mineralized MWCNTs–OH/BSA composite.
- Published
- 2011
42. Preparation and Capacitive Properties of Nickel-manganese Oxides/Multiwalled Carbon Nanotube/Poly (3,4-ethylenedioxythiophene) Composite Material for Electrochemical Supercapacitor
- Author
-
M. V. Kiamahalle, Sharif Hussein Sharif Zein, C. I. Cheng, S. Buniran, and S. A. Sata
- Subjects
chemistry.chemical_compound ,Nickel ,Nanotube ,Multidisciplinary ,Materials science ,chemistry ,Capacitive sensing ,Electrochemical supercapacitors ,chemistry.chemical_element ,Manganese ,Composite material ,Multiwalled carbon ,Poly(3,4-ethylenedioxythiophene) - Published
- 2011
43. Optimization of the mechanical properties of calcium phosphate/multi-walled carbon nanotubes/bovine serum albumin composites using response surface methodology
- Author
-
Kah Ling Low, Soon Huat Tan, David S. McPhail, Aldo R. Boccaccini, and Sharif Hussein Sharif Zein
- Subjects
Materials science ,biology ,Central composite design ,Quadratic model ,chemistry.chemical_element ,Carbon nanotube ,Calcium ,law.invention ,Compressive strength ,chemistry ,law ,biology.protein ,Process optimization ,Response surface methodology ,Bovine serum albumin ,Composite material - Abstract
Response surface methodology (RSM) coupled with the central composite design (CCD) was used to optimize the mechanical properties of calcium phosphate cement/multi-walled carbon nanotubes/bovine serum albumin (CPC/MWCNTs/BSA) composites. In this study, CPC composites were reinforced by multi-walled carbon nanotubes (MWCNTs) and bovine serum albumin (BSA) in order to induce high mechanical properties in the CPC/MWCNTs/BSA system. The effect of various process parameters on the compressive strength of CPC/MWCNTs/BSA composites was studied using design of experiments (DOE). The process parameters studied were: wt.% of MWCNTs (0.2–0.5 wt.%), wt.% of BSA (5–15 wt.%) and type of MWCNTs (e.g. as-pristine MWCNT (MWCNT-AP), hydroxyl group functionalized MWCNT (MWCNT-OH) and carboxyl group functionalized MWCNT (MWCNT-COOH)). Based on the CCD, a quadratic model was obtained to correlate the process parameters to the compressive strength of CPC/MWCNTs/BSA composites. From the analysis of variance (ANOVA), the most significant factor affected on the experimental design response was identified. The predicted compressive strength after process optimization was found to agree well with the experimental value. The results revealed that at 0.5 wt.% of MWCNT-OH and 15 wt.% of BSA, the highest compressive strength of 14 MPa was obtained.
- Published
- 2011
44. Synthesis, Characterization and Biodegradation of Novel Poly(L-lactide)/Multiwalled Carbon Nanotube Porous Scaffolds for Tissue Engineering Applications
- Author
-
Sharif Hussein Sharif Zein, Soon Huat Tan, Hazizan Md Akil, Abdul Latif Ahmad, and Hassan Adeli
- Subjects
Nanotube ,Materials science ,Biomedical Engineering ,Pharmaceutical Science ,Medicine (miscellaneous) ,Bioengineering ,Biodegradation ,Multiwalled carbon ,Porous scaffold ,Characterization (materials science) ,Tissue engineering ,Chemical engineering ,Poly-L-lactide ,Composite material ,Biotechnology - Published
- 2011
45. Reinforcement of calcium phosphate cement with multi-walled carbon nanotubes and bovine serum albumin for injectable bone substitute applications
- Author
-
Sharif Hussein Sharif Zein, Aldo R. Boccaccini, LC Lutz-Christian Gerhardt, Judith A. Roether, Kean-Khoon Chew, Kah-Ling Low, David S. McPhail, and Soft Tissue Biomech. & Tissue Eng.
- Subjects
Calcium Phosphates ,Materials science ,Compressive Strength ,Surface Properties ,Scanning electron microscope ,Biomedical Engineering ,Serum albumin ,Dental Cements ,Carbon nanotube ,Injections ,law.invention ,Biomaterials ,chemistry.chemical_compound ,X-Ray Diffraction ,law ,Materials Testing ,Spectroscopy, Fourier Transform Infrared ,Animals ,Fourier transform infrared spectroscopy ,Composite material ,Bovine serum albumin ,Mechanical Phenomena ,biology ,Nanotubes, Carbon ,Serum Albumin, Bovine ,Phosphate ,Durapatite ,Compressive strength ,chemistry ,Chemical engineering ,Mechanics of Materials ,Bone Substitutes ,Microscopy, Electron, Scanning ,Anhydrous ,biology.protein ,Cattle - Abstract
This paper presents the development of novel alternative injectable calcium phosphate cement (CPC) composites for orthopaedic applications. The new CPC composites comprise β -tri-calcium phosphate ( β -TCP) and di-calcium phosphate anhydrous (DCPA) mixed with bovine serum albumin (BSA) and incorporated with multi-walled carbon nanotubes (MWCNTs) or functionalized MWCNTs (MWCNTs–OH and MWCNTs–COOH). Scanning electron microscopy (SEM), compressive strength tests, injectability tests, Fourier transform infrared spectroscopy and X-ray diffraction were used to evaluate the properties of the final products. Compressive strength tests and SEM observations demonstrated particularly that the concomitant admixture of BSA and MWCNT improved the mechanical properties, resulting in stronger CPC composites. The presence of MWCNTs and BSA influenced the morphology of the hydroxyapatite (HA) crystals in the CPC matrix. BSA was found to act as a promoter of HA growth when bounded to the surface of CPC grains. MWCNT–OH-containing composites exhibited the highest compressive strengths (16.3 MPa), being in the range of values for trabecular bone (2–12 MPa).
- Published
- 2011
46. OPTIMIZATION OF THE MECHANICAL STRENGTH PROPERTIES OF POLY(L-LACTIDE)/MULTI-WALLED CARBON NANOTUBE SCAFFOLDS USING RESPONSE SURFACE METHODOLOGY
- Author
-
Soon Huat Tan, Hassan Adeli, Abdul Latif Ahmad, and Sharif Hussein Sharif Zein
- Subjects
Materials science ,Central composite design ,Design of experiments ,Composite number ,Carbon nanotube ,Condensed Matter Physics ,law.invention ,Solvent ,law ,Poly-L-lactide ,Mechanical strength ,General Materials Science ,Response surface methodology ,Composite material - Abstract
In this study the response surface methodology (RSM) coupled with the central composite design (CCD) were used to optimize the mechanical strength properties of poly(L-lactide)/multi-walled carbon nanotube (MWCNT) scaffolds. The scaffolds were prepared by the freeze-extraction method. MWCNTs were incorporated into PLLA composite as a reinforcement agent in order to improve the strength properties of the scaffolds. The effect of process parameters such as ratio of PLLA/(PLLA + MWCNT) (93–100%), solvent amount (100–200 ml), freezing time (5–7 h) and immersing time (2–4 days) were studied using the design of experiment (DOE). Based on CCD, quadratic model was obtained and developed to correlate the process parameters to the strength of the scaffolds. An analysis of variance (ANOVA) was applied to determine the significant factors affecting the experimental design response (strength) of the scaffolds. The predicted values after optimization process were in good agreement with the experimental values. The model was able to accurately predict the response of strength with less than 5% error.
- Published
- 2011
47. <font>MnO2</font>-FILLED MULTIWALLED CARBON NANOTUBE/POLYANILINE NANOCOMPOSITES: EFFECT OF LOADING ON THE CONDUCTION PROPERTIES AND ITS PERCOLATION THRESHOLD
- Author
-
Saiful Izwan Abd Razak, Abdul Latif Ahmad, and Sharif Hussein Sharif Zein
- Subjects
Nanotube ,Thermogravimetric analysis ,Materials science ,Nanocomposite ,Percolation threshold ,Conductivity ,Condensed Matter Physics ,chemistry.chemical_compound ,chemistry ,Percolation theory ,Percolation ,Polyaniline ,General Materials Science ,Composite material - Abstract
This paper reports the synthesis and characterization of ternary nanocomposites consisting of polyaniline (PANI), multiwalled carbon nanotubes (MWCNTs) and manganese dioxide (MnO2) at different MWCNT– MnO2 loadings. The composite electrical percolation threshold is investigated as well. The in situ nanocomposites were characterized by UV-visible, Fourier transform and Raman spectroscopy, thermogravimetric analysis, field emission scanning electron microscopy, and electrical conductivity measurements. The conductivity of the nanocomposite reached up to 78.79 Scm-1 with 50 wt.% addition of MWCNT– MnO2 with good conduction stability and reversibility. The percolation threshold of this nanocomposite was achieved at 0.5 wt.%. Using the scaling law of the percolation theory, it was found that the theoretical conductivity of the nanocomposite exhibited an exponential factor, (t) of 1.38 instead of the universal t value of 2.
- Published
- 2011
48. Poly(3-hydroxybutyrate)-functionalised multi-walled carbon nanotubes/chitosan green nanocomposite membranes and their application in pervaporation
- Author
-
Yit Thai Ong, Kumar Sudesh, Abdul Latif Ahmad, Sharif Hussein Sharif Zein, and Soon Huat Tan
- Subjects
chemistry.chemical_classification ,Thermogravimetric analysis ,Materials science ,Nanocomposite ,Analytical chemistry ,Filtration and Separation ,Carbon nanotube ,Polymer ,Analytical Chemistry ,law.invention ,Chitosan ,chemistry.chemical_compound ,Membrane ,chemistry ,Chemical engineering ,law ,Pervaporation ,Fourier transform infrared spectroscopy - Abstract
The aim of this research was to align poly(3-hydroxybutyrate) (PHB)-functionalised multi-walled carbon nanotubes (MWCNTs) into a chitosan matrix. The MWCNTs were first functionalised with PHB and aligned into a membrane filter template through a filtration process. A solution casting technique was then applied to cast the chitosan onto the template to form PHB-MWCNT/chitosan nanocomposite membranes. The functionalised MWCNTs and resulting membranes were characterised using thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The TGA demonstrated that approximately 40 wt.% of the PHB was successfully functionalised in the MWCNTs, and TEM showed that the polymer wrapped on the nanotubes surface. The presence of the PHB functional moieties helped to improve the dispersion and compatibility of the MWCNTs in the chitosan matrix. When we applied the PHB-MWCNT/chitosan nanocomposite membranes in the pervaporation process of 1,4-dioxane dehydration, the nanocomposite membrane showed a relatively high permeation flux and selectivity towards water, compared to existing membrane.
- Published
- 2011
49. EFFECT OF PARA-HYDROXYBENZENE SULFONIC ACID ON THE PROPERTIES OF EX SITU PREPARED POLYANILINE/MULTIWALLED CARBON NANOTUBES–<font>MnO2</font>
- Author
-
Saiful Izwan Abd Razak, Sharif Hussein Sharif Zein, and Abdul Latif Ahmad
- Subjects
chemistry.chemical_classification ,Conductive polymer ,Nanocomposite ,Materials science ,Polyaniline nanofibers ,Dopant ,Carbon nanotube ,Sulfonic acid ,Condensed Matter Physics ,law.invention ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Transmission electron microscopy ,law ,Polymer chemistry ,Polyaniline ,General Materials Science - Abstract
New ex situ polyaniline (PANI)/ MnO2 -filled multiwalled carbon nanotubes (MWCNTs) nanocomposites using para-hydroxybenzene sulfonic acid (PHBSA) as a dopant and linker exhibit enhanced electrical conductivity and interfacial interaction. Strong and enhanced interfacial interaction was observed on the surfaces of the filled carbon nanotubes and PANI. Transmission electron microscope (TEM) demonstrated clearly the improved bonding at the interface compared to the nanocomposite without PHBSA.
- Published
- 2010
50. Remarkable Stability of Supercapacitor Material Synthesized by Manganese Oxide Filled in Multiwalled Carbon Nanotubes
- Author
-
Suhairi A. Sata, Surani Buniran, Meisam Valizadeh Kiamahalleh, and Sharif Hussein Sharif Zein
- Subjects
Supercapacitor ,Materials science ,Potential applications of carbon nanotubes ,Chemical engineering ,Biomedical Engineering ,Pharmaceutical Science ,Medicine (miscellaneous) ,Bioengineering ,Multiwalled carbon ,Manganese oxide ,Biotechnology - Published
- 2010
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