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Planning and coordination of modular construction
No full textDespite the advances of modular construction, the comprehensive understanding of its technical aspects in buildings is still limited, especially during the implementation process. This paper reviews the technical aspects of planning and coordination of modular construction in the building industry. The unclear onsite and practical knowledge need to be clarified for the implementation process. It then leads to the questions on the status of research development and gaps of the technical aspects. One hundred and thirty papers were filtered and analyzed through a systematic review. Four technical aspects of modular construction were found, namely (a) feasibility aspects of modular construction, (b) types of construction or materials, (c) design and structural analyses, and (d) construction planning. The findings render insightful references for the successful delivery of modular construction including its lifecycle analysis and sustainability needs. A research framework is also developed to highlight the gaps and measures for future practice
Imidazolium-based ionic liquids as demulsifier for water-crude oil emulsion
No full textMost of the crude oils in the world are produced as water-crude oil emulsions. Removal of water from the emulsions is one of the major issues in the industry and the process is completed before transportation and refining. One of the methods to remove water is through demulsification. In the present study, ionic liquids, non-volatile and non-toxic solvents, are used as demulsifiers. Three ionic liquids (ILs), namely 1-ethyl-3-methylimidazolium acetate (EMIM-AC), 1-butyl-3-methylimidazolium chloride (BMIM-Cl) and 1-butyl-3-methylimidazolium hydrogen sulfate (BMIM-HSO4), were evaluated to treat a heterogeneous mixture of crude oil and water. The bottle tests were conducted at 60 °C and salinity of 50,000 ppm. Response surface methodology (RSM) was used to study the effect of IL type, its concentration, and residence time towards demulsification efficiency. The developed correlation gave a high correlation coefficient, R2 of 0.924. Analysis shows that the IL concentration gives the highest influence on the demulsification efficiency, followed by the residence time and the type of ionic liquid. Among the three ILs investigated, 1000 ppm BMIM-HSO4 achieved the highest demulsification efficiency, where complete separation (100% demulsification efficiency) was attained within 30 min. BMIM-Cl achieved 72% efficiency after an hour while the EMIM-AC reached maximum separation after 52 min with 45% efficiency
Beyond conventional biomass valorisation: pyrolysis-derived products for biomedical applications
Get PDFBiomass valorisation is conventionally associated with the production of green biofuels. However, this could extend beyond the conventional perception of biomass application into other domains such as medical sciences. Acid condensate (AC) obtained from pyrolysis promises a good potential for biomedical applications, notably for its antimicrobial, antioxidant, and anti-inflammatory properties. In this study, concentrated AC extract (CACE) obtained from microwave-assisted pyrolysis of palm kernel shells was fractionated, and the resulting fractions were pooled according to similar thin layer chromatography profiles into combined fractions (CFACs). CFACs were evaluated for total phenolic content, antioxidant level, cytotoxicity, and wound healing activities toward human skin fibroblast cells (HSF 1184). CFAC-3 showed the highest total phenolic content (624.98 ± 8.70 µg GAE/mg of sample) and antioxidant activities (DPPH IC50 of 29.47 ± 0.74 µg/mL, ABTS of 1247.13 ± 27.89 µg TE/mg sample, FRAP of 24.26 ± 0.71 mmol Fe(II)/mg sample, HFRS of 257.74 ± 1.74 µg/mL) compared to CACE (DPPH IC50 of 81.76 ± 2.81 µg/mL, ABTS of 816.95 ± 30.49 µg TE/mg sample, FRAP of 9.22 ± 0.66 mmol Fe(II)/mg sample, HFRS of 689.30 ± 36.00 µg/mL), no cytotoxic properties at =50 µg/mL, and significantly faster wound closure (at 1.25 µg/mL) compared to the control 12 h after treatment. The phosphorylation of the phosphatidylinositol 3-kinase (PI3K) and protein kinase B (AKT) were upregulated, thus indicating that wound healing of CFAC-3 followed through this signalling pathway. To conclude, phenolic-rich CFAC-3 obtained from the pyrolysis of palm kernel shells demonstrated potential biomedical application as an alternative wound healing agent with high antioxidant and wound-healing activity. To the best of our knowledge, this was the first study to report on the wound healing activity of AC and its wound healing mechanism
Testing content validity of teacher-made test: Profiling teacher perceptions and demographic variables
Get PDFThe content validity of teacher-made tests (TMT) in Malaysian Chinese primary schools was explored in this research. The study used teacher-made tests to analyze the selected Chinese primary schools, which have yet to be thoroughly explored in the context of these school types. It also investigated how well teachers in the sampled schools understand the table of specifications (TOS). The study further examined the extent to which included demographic variables affect the validity of teacher-made tests. A total of 660 questionnaires were distributed randomly to teachers from 21 Chinese primary schools. There were 381 completed questionnaires (58% of total rate) received and analyzed. The findings demonstrated that most teachers have a basic understanding of the TOS and that teacher-made test levels are valid. K-group MANOVA analysis also revealed that work experience and age had a significant influence on teacher understanding. Work experience and age, on the other hand, had no effect on the teacher-made test. Furthermore, the findings demonstrated that both teacher understanding and teacher-made tests were unaffected by teacher gender
Microalgae dewatering using forward osmosis membrane: a review
No full textMicroalgae have attracted a considerable interest recently due to its potential in various applications, especially in renewable energy and material production industries. Microalgae harvesting technique is featured to be a valuable separation technique within the massive scale generation of bio-products derived from microalgae. Large energy consumption and cost yet poor efficacy are the major limitations of the currently available dewatering operations. Therefore, the energy efficiency and cost involved in microalgae harvesting must be improved to increase the sustainability of microalgae utilization. The use of forward osmosis (FO), an emerging membrane separation technique based on osmotic pressure, for microalgae dewatering demonstrates various benefits, for instance minimal energy consumption and high efficiency. However, FO is also challenged by several limitations, including membrane fouling, reverse draw solutes, and concentration polarization. Considerable studies have focused on providing solutions to these problems, and this paper aims to review the most important studies that have been conducted to date on microalgae dewatering. Particular attention has been made on the challenges related to the application of forward osmosis including the membrane fouling during microalgae dewatering. Several strategies have been proposed, including membrane materials, optimized module design, microalgae species and its culture environment, as well as the selection of draw solution
Topography induced stress and its influence on tunnel excavation in hard rocks - a numerical approach
No full textIn-situ stress characterisation is essential for anticipating the viability of underground structures. In areas with rugged topography, the in-situ stress varies within short distances and cannot be characterized by limited in-situ stress measurements. The in-situ stress at a point below the ground surface results from the combined effect of topography, tectonic forces, material properties and many others. The impact of topography on subsurface in-situ stress can be significant in areas with rugged topography. In this study, 3D finite element modelling utilising the Digital Elevation Model of a tunnelling project site is used to characterise the in-situ stress. Gravity loading was assumed to simulate the impact of topography on the subsurface in-situ state of stress. The reliability of the results was validated by analysing the stress-induced brittle failures in a section of the tunnel. The simulated in-situ principal stresses and the corresponding stress-induced failure zones were in good agreement with the actual observations in the tunnel. The results suggest that the present-day topography dominates the in-situ stress in the study area
Preliminary study of structural changes of Glucose-6-phosphate dehydrogenase deficiency variants
Get PDFGlucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzyme deficiency disorder affecting over 400 million individuals worldwide. G6PD protects red blood cells (RBC) from the harmful effects of oxidative substances. There are more than 400 G6PD mutations, of which 186 variants have shown to be linked to G6PD deficiency by decreasing the activity or stability of the enzyme. Different variants manifest different clinical phenotypes which complicate comprehending the mechanism of the disease. In order to carry out computational approaches to elucidate the structural changes of different G6PD variants that are common to the Asian population, a complete G6PD monomer-ligand complex was constructed using AutoDock 4.2, and the molecular dynamics simulation package GROMACS 4.6.7 was used to study the protein dynamics. The G410D and V291M variants were chosen to represent classes I and II respectively and were created by in silico site-directed mutagenesis. Results from the Root mean square deviation (RMSD), Root mean square fluctuation (RMSF) and Radius of gyration (Rg) analyses provided insights on the structure - function relationship for the variants. G410D indicated impaired dimerization and structural NADP binding while the impaired catalytic activity for V291M was indicated by a conformational change at its mutation site
Valorization of food waste and poultry manure through co-composting amending saw dust, biochar and mineral salts for value-added compost production
No full textThe present study proposes a system for co-composting food waste and poultry manure amended with rice husk biochar at different doses (0, 3, 5, 10%, w/w), saw dust, and salts. The effect of rice husk biochar on the characteristics of final compost was evaluated through stabilization indices such as electrical conductivity, bulk density, total porosity, gaseous emissions and nitrogen conservation. Results indicated that when compared to control, the biochar amendment extended the thermophilic stage of the composting, accelerated the biodegradation and mineralization of substrate mixture and helped in the maturation of the end product. Carbon dioxide, methane and ammonia emissions were reduced and the nitrogen conservation was achieved at a greater level in the 10% (w/w) biochar amended treatments. This study implies that the biochar and salts addition for co-composting food waste and poultry manure is beneficial to enhance the property of the compost
Insights into the potential application of magnetic field in controlling sludge bulking and foaming: A review
Get PDFThe formation of bulking and foaming in biological wastewater treatment could cause a series of operational issues with biomass and effluent quality, ultimately affect the treatment performance of the system. The essential parameters influencing the growth of bulking and foaming bacteria are comprehensively summarised in this paper. Existing bulking and foaming control approached are critically reviewed and addressed, as well as their drawbacks and limitations. Despite the abundance of information and implementation, a complete control technique for limiting filamentous sludge bulking and foaming remains insufficient. Magnetic field application is emphasised as a viable control strategy in this regard. The present review study provides new insight of this application by comparing the use of magnetic fields to conventional treatments. Future outlooks on the use of magnetic fields to prevent BFB proliferation were also highlighted
Photocatalytic membrane technologies for removal of recalcitrant pollutants
No full textMassive grow of population has led to increase in waste production not only from domestic activities but also industries, that cause an increase of emerging contaminants in wastewater and water bodies. Recalcitrant pollutants like dyes and drugs, including endocrine-disrupting chemicals (EDCs) became the main pollutant in wastewater which may cause several health problems for human and animals. EDCs can interfere the endocrine systems, and cause several problems such as human reproduction, Alzheimer's, thyroid, obesity, cancer and reproductive system of aquatic animals. Dyes are toxic, carcinogenic, and can reduce oxygen and light penetration in the photosynthesis process. The persistent properties cause the conventional wastewater treatment, which mostly employed biodegradation process, to be inadequate in treating the pollutants, hence, poor quality effluent is released into the water bodies. Thus, this article reviewed the photocatalytic membrane technologies as an advanced wastewater treatment alternative to improve the effluent quality. The review included the photocatalytic membrane fabrication, characterization, and various modifications to enhance the photocatalytic membrane performances. The presence of the photocatalyst provides a high rate of pollutants degradation as well as enhancement of the membrane performance by preventing membrane fouling and flux from declining. Modification of photocatalytic membrane by binary photocatalyst is highlighting the improvement of visible light-response photoactivity