Performance of nano metaclay on chloride diffusion for ultra- high performance concrete

The major cause for corrosion of steel reinforcement embedded in concrete due to chloride penetration has been the great research effort. The use of nano metaclay in UHPC increase the strength and helps the formation of micro pores by acting as a filler thus improve the chloride penetration resistance characteristic. The aim of this study is to evaluate the chloride diffusion of UHPC using RCPT and chloride penetration depth. Four (4) series of UHPC comprised of plain UHPC and a series of nanoUHPC incorporating 1%, 3% and 5% of nano metaclay were produced. It is reported that the compressive strength of nano UHPCl exhibits higher strength up to 10% compared to plain UHPC. The results showed that UHPC containing nano metaclay also significantly affect the chloride diffusion coefficient. As regards to the results, inclusion of 1% nano metaclay in UHPC led to noticeable benefit towards strength and chloride resistance

Metal organic framework mixed-matrix membrane for arsenic removal

Metal organic framework (MOF) is a recent class of porous materials that are built from metal cluster and organic linker. Among the discovered MOFs, UiO-66 has demonstrated both attributes of water stability and hydrophilic, making it suitable for wastewater treatment. In this study, 0.5 wt% UiO-66 was integrated into polysulfone membrane as nanofiller to form mixed-matrix membrane (MMM) with a thin-film composite, dense polyamide layer formed on top of the substrate layer that intended to remove 100 ppm of arsenic V from wastewater through forward osmosis. The successful synthetization of UiO-66 nanoparticle was proven by XRD and FESEM. The pure water permeability was significantly higher with the presence of LiCl in dope solution as pore former. It was found that the arsenic rejection achieved was 87.5% with satisfactory water flux and salt reverse flux

Factors influencing students’ intention to use internet for academic purposes

This study aimed to investigate the factors influencing students’ intention to use the Internet for academic purposes amongst 204 final year business students in public universities in Malaysia.This study integrated theory of planned behavior (TPB) and theory of acceptance model (TAM) as the base model toward that purpose.The research model employs the variables from both theories namely attitudes, subjective norms, perceived behavioral control, perceived usefulness, perceived ease of use, intention, and behavior.A multiple regression analysis provides empirical support for the applicability of integration of TPB and TAM in predicting students’ intention to use the Internet for academic purposes.Results of the study show that attitudes, perceived behavioral control, and perceived usefulness are statistically significant in influencing intention to use the Internet for academic purposes.Based on the results, it can be concluded that students’ intention to use the Internet for academic purposes could be predicted from their attitudes, perceived behavioral control, and perceived usefulness at 49% level.In view of the results, several implications and recommendations are discussed

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

Background: The EMPA KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population. Methods: EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110. Findings: Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5–2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62–0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16–1·59), representing a 50% (42–58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1). Interpretation: In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease. Funding: Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council

Behaviour of Metakaolin Concrete in Different Curing Condition

This paper presents the result of an investigation on the effect of curing condition on concrete containing Metakaolin. Concrete grade 40 was used in this research and Metakaolin is replaced from 5%, 10% and 15%. All sample been cured by using three different curing condition which is normal curing (+20o C), expose curing (28 – 34o C) and high temperature curing (+55o ). The effect of Metakaolin on concrete will be seen by physical and mechanical properties. From physical properties the effect of Metakaolin will be seen by using soundness, setting time and workability and for mechanical properties compression and flexural test will be performed. From physical test shows Metakaolin reduce the workability of concrete and hence increase the water demand in concrete mix but the addition of Metakaolin reduce the ability of cement paste to expand. This happen because the addition of Metakaolin will fill the void around the cement paste. Results from physical test are supported by testing the mechanical part. Results show that concrete containing Metakaolin improved in all curing condition except for high temperature curing. These can be seen from compression test that shows Metakaolin increase strength of concrete except for high temperature curing. The same phenomena can be seen from flexural test. Results show the optimum replacement is at 10% and the best curing effect for Metakaolin is normal curing. Three elements that contribute to the result is the addition of Metakaolin act as a filler, accelerate the cement hydration and pozzolanic reaction that improve the physical and mechanical properties

Performance of polymer electrolyte membrane for direct methanol fuel cell application: perspective on morphological structure

Membrane morphology plays a great role in determining the performance of polymer electrolyte membranes (PEMs), especially for direct methanol fuel cell (DMFC) applications. Membrane morphology can be divided into two types, which are dense and porous structures. Membrane fabrication methods have different configurations, including dense, thin and thick, layered, sandwiched and pore-filling membranes. All these types of membranes possess the same densely packed structural morphology, which limits the transportation of protons, even at a low methanol crossover. This paper summarizes our work on the development of PEMs with various structures and architecture that can affect the membrane’s performance, in terms of microstructures and morphologies, for potential applications in DMFCs. An understanding of the transport behavior of protons and methanol within the pores’ limits could give some perspective in the delivery of new porous electrolyte membranes for DMFC applications

Novel cross-linked enzyme aggregates of levanase from bacillus lehensis g1 for short-chain fructooligosaccharides synthesis: developmental, physicochemical, kinetic and thermodynamic properties

Short-chain fructooligosaccharides (scFOSs) can be produced from the levan hydrolysis using levanase. Levanase from Bacillus lehensis G1 (rlevblg1) is an enzyme that specifically converts levan to scFOSs. However, the use of free levanase presents a lack of stability and reusability, thus hindering the synthesis of scFOSs for continuous reactions. Here, CLEAs for rlevblg1 were prepared and characterized. Cross-linked levanase aggregates using glutaraldehyde (CLLAs-ga) and bovine albumin serum (CLLAs-ga-bsa) showed the best activity recovery of 92.8% and 121.2%, respectively. The optimum temperature of CLLAs-ga and CLLAs-ga-bsa was increased to 35 °C and 40 °C, respectively, from its free rlevblg1 (30 °C). At high temperature (50 °C), the half-life of CLLAs-ga-bsa was higher than that of free rlevblg1 and CLLAs-ga. Both CLLAs exhibited higher stability at pH 9 and pH 10. Hyperactivation of CLLAs-ga-bsa was achieved with an effectiveness factor of more than 1 and with improved catalytic efficiency. After 3 h reaction, CLLAs-ga-bsa produced the highest total scFOSs yield of 35.4% and total sugar of 60.4% per gram levan. Finally, the reusability of CLLAs for 8 cycles with more than 50% activity retained makes them as a potential synthetic catalyst to be explored for scFOSs synthesis

How has Malaysia benefited from the high-resolution satellite rainfall? Trends, gaps and further research opportunities

This paper presents a scientific review on how Malaysia has benefited from the high-resolution satellite rainfall since its first launch in 1998. As a tropical country in which the environment is highly characterised by rainfall dynamics, public domain access of high-resolution satellite rainfall data could be very useful to support the hydrologic and related environmental studies. The scope of this paper includes achievements, the trend of studies, as well as gaps and future opportunities for scientific research. Examining this element is crucial in determining the present information on the status quo of the applications of space-based technology to Malaysian hydrologic research. Furthermore, this information is critical to charter the future action for the policymakers and revision of respective disciplines, including climate change, environmental sustainability, disaster resilience, food security, and education. Based on the search throughout the largest scientific databases of Web of Science and Scopus, five major trends have been identified. Those trends were ranked based on the number of research, 1) Satellite rainfall data performance and quality evaluation (40%), 2) Satellite rainfall data as input to environmental modelling (27%), 3) Rain fade & telecommunication (16%), 4) Satellite rainfall data quality improvement (7%), and 5) Rainfall studies. These trends were identified about 11 years after the satellite rainfall project started in 1998. The major achievement till now is validating the accuracy of the satellite rainfall and also downscaling it for local application

Synthesis and characterization of superoleophobic fumed alumina nanocomposite coated via the sol-gel process onto ceramic-based hollow fibre membrane for oil-water separation

Oily wastewater treatment is a global challenge due to the substantial amount of effluent resulted from many industrial and domestic activities. To overcome the challenge of using existing treatment approach and fouling, superoleophobic coatings were fabricated. In this study, a superoleophobic membrane surface was obtained using the sol-gel technique with perfluorooctanoate (PFO), poly (diallyl dimethylammonium chloride) (PDADMAC), and nanoparticles as complex-polymer nanocomposites. The effects of coating cycles on the surface structure, chemical properties, surface chemistry, and oleophobicity of the surface were examined using field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and oil contact angle measurement. The results showed that the coated layer successfully adhered to the substrate surface. However, the chemical stability with respect to oil contact angle (OCA) revealed a decline at pH 7 and pH 9 and maintained stability at pH 3. Besides, oil flux at 63.0 L/m2. h was achieved for PDADMAC-Al2O3/44 wt% PFO and the highest separation efficiency of 98% was obtained. Furthermore, the oil rejection decreases as the oil concentration increases from 1 to 3 g/L. OCA of 155° was obtained after 5 coating cycles. Apart from mitigating substrate fouling, the superoleophobic and superhydrophilic coating can be applied to a ceramic-based hollow fibre membrane and efficiently used for the separation of oil from oily wastewater