Publications

Objective: Bisphenol A (BPA), a xenoestrogen chemical compound has wide range of harmful effects in the body. It is not clear whether BPA induced harmful effects in the body occurs through disrupting the intestinal barrier (IB). Objective of this review is to provide an up to date information about the effect of BPA on the IB. Materials and Methods: Literatures were searched in PubMed, Scopus and Google Scholar using the key words 'BPA' paired with 'intestinal barrier', 'intestinal barrier function', 'gut barrier function', 'gut' and 'intestinal permeability' from the year 1980 till early March 2018. Results: Only six animal studies were found. BPA was found to increase intestinal permeability, an indicator of compromised IB in one study. But it dose-dependently decreased intestinal permeability in ovariectomized animals. BPA has been reported to alter gut microbiota in five studies. Altered gut microbiota is proposed to be an important factor contributing to compromised IB. Conclusion: The effect of BPA on the IB varies on the species, gender, presence or absence of endogenous estrogen and maturity of the gut. However, five out of six studies are in agreement that BPA altered intestinal microbial flora.

Due to the significant energy and economic losses brought on by the global oil spill, there has been an increased interest in oil-water separation. This study presents strong non-linear machine learning models (support vector regression (SVR) and Gaussian process regression (GPR)) with the Response surface method (RSM) to predict the oil flux and oil-water separation efficiency of wastewater using ceramic membrane technology. For the model development and prediction of oil flux (OF) and oil-water separation efficiency (OSE), oil concentration (mg/L), feed flow rate (mL/min), and pH were considered as input variables. The input variables are combined in three combinations to study the most contributing input features to the models’ performance. Mean square error (MSE) and Nash-Sutcliffe coefficient efficiency (NSE) were used to assess the prediction performances of the developed models with the different number of input combinations considered in the study. For the two target variables (OF and OSE), GPR and SVR models were used to separately predict them. For OF, the SVR-2 [Combo-2] model (MSE = 0.9255 and NSE = 2.7976) performed better with higher prediction accuracy compared to GPR-2 [Combo-2] model (MSE = 0.763 and NSE = 6.437). In addition, for OSE, the GPR-3 [Combo-3] model (MSE = 0.995 and NSE = 0.5544) performed slightly better than SVR-3 [Combo-3] model (MSE = 0.992 and NSE = 0.8066). The results showed that the SVR model with the combo-2 and GPR-3 models for OF and OSE variables are the proposed models with the best performance and accuracy. This machine learning study will aid in better evaluating the function of materials such as ceramic in membrane performance features such as oil flux and rejection prediction, separation efficiency, water recovery, membrane fouling, and so on. As for academics and manufacturers, this machine learning (ML) strategy will boost performance and allow a better understanding of system governance.

Clean water scarcity is a critical issue faced by the world. It was caused by insufficient potable water supply and a high cost of water purification systems. As a result, a photothermal evaporator system with the property to absorb light/solar energy and then convert it to heat energy has been rapidly developed. In this work, a solar-driven water evaporation was designed for desalination. The solar evaporator comprises a photothermal molybdenum disulfide-titanium dioxide (MoS2-TiO2) composite layer supported onto a cheap filter paper attached. The filter paper was attached to polystyrene foam for support and cotton thread in the centre of the filter paper for water transportation. MoS2-TiO2 composite was synthesized and coated onto the filter paper using a simple vacuum-assisted method. Before the solar-driven water evaporation testing, the MoS2-TiO2 composite was first characterized using XRD and Raman spectroscopy. The characterization results indicate that MoS2 introduction into the TiO2 structure improved the photosensitivity due to the reduction of the bandgap energy from 3.1 eV for TiO2 to 1.6 eV. The performance of the developed solar evaporator was tested using 35,000 ppm NaCl solution under sunlight for 24 h intermittently. The TiO2-MoS2 solar evaporator was observed to have the highest photothermal ability, with 0.807 kg‧m-2‧h-1 evaporation performance and 55.9 % photothermal efficiency compared to other solar evaporators. This indicated that introducing the photothermal MoS2-TiO2 layer could enhance the solar evaporator performances, making it promising for the desalination application, particularly in impoverished areas with water scarcity.

Tuning the ratio of sp2/sp3 is crucial factor for obtaining high aspect ratio of graphene oxide. In this work, we reported a comprehensive study on synthesis of GO with different sp2/sp3 ratios at different oxidation reaction temperatures. The physicochemical properties of the as-prepared GO were characterized by Attenuated total reflectance infrared spectroscopy (ATR-IR), Raman spectroscopy, Solid-state nuclear magnetic resonance (SSNMR), Field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Transmission electron microscope (TEM), hydrophilicity test and zeta potential. Interestingly, GO-35 showed the smallest contact angle with carbon-to-oxygen (O/C) ratio 0.469. ATR-IR reveals the different intensity of hydroxyl (−OH), carbonyl (−CO), epoxy (C–O–C), as well as carboxyl (−COOH) moieties in the GO samples, and their intermolecular interactions significantly affected the interlayer spacing between consecutive identical planes of carbon atoms which examined using XRD. XPS confirmed that the basal species such as –OH is abundantly available in the GO-35 and unavailable in GO-50. Our results demonstrate that the properties of GO can be tuned using different oxidation reaction temperatures, which significantly influences types of oxygen-functional groups generated at different oxidation levels, thus could pave the way for various applications of graphene-based material.

A modified enzyme-based biosensor was developed for amperometric measurement of total Malachite Green (sum of MG and LMG) in tilapia fish. The 4 UmL-1 butyrylcholinesterase enzyme (BuChE) was used and immobilized onto the surface of carbon paste electrode during the electro-polymerization of polypyrrole (PPy). It is a simple, rapid and sensitive technique used for determination of total MG using 0.1M phosphate buffer pH 8.0. In this study, butyrylthiocholine iodide (0.3 Mm BTCi) was used as a substrate which produced the thiocholine due to the enzymatic hydrolysis. Then, it was oxidized at 0.4V against silver-silver chloride electrode for 100 s. The modified enzyme biosensor provided a high sensitivity and linear concentration range from 0.25 to 10 ppb with a limit of detection (LOD) at 0.25 ppb. The results showed the linear standard curve of total MG standard solution (based on the current output in microampere) with the equation of y = - 0.9113x + 10.84, R2 = 0.9445.

As one of popular destinations in Indonesia for tourism, Lombok Island has been confronted with an overgeneration of solid waste recently. About 600 metric ton (Mt) of the waste is generated daily with 40 % of it as non-biodegradable waste. Amidst the challenges of climate change and the need for decarbonization, this case-study investigates various challenges in strengthening synergies between waste management and climate change mitigation in Lombok, while exploring opportunities to accelerate decarbonization in the waste sector through circular-economy digitalization. Case study of digitalization-based waste recycling in Hainan Island (China) are presented as a model for Lombok to replicate its successful story on how digital technologies contribute to sustainability with respect to efficiency and waste circularity. To obtain relevant data, the research questions cover: How did both Hainan and Lombok Islands deal with the challenges and opportunities associated with digitalization-based circular economy (CE)? What are the implications of digitalization-based waste recycling on the society and economy? It was found that digital revolution has affected all sectors including the waste sector in Hainan. As digitalization has expanded in all sectors, this creates opportunities to optimize waste recycling and decrease GHG emissions, while driving decarbonization across the economy. About 90 % of waste avoidance was attained in Hainan when using digitalization for waste recycling. CE strategies also complement decarbonization to reduce GHG emission from material production through waste recycling, while minimizing its direct emission from local landfills. While the digitalization-based approach is promising for improving waste management in Lombok, its appropriateness and feasibility depend on the Island's socio-economic conditions and digital readiness. The findings underline the importance of integrating digital solutions into local waste management and calls for collaboration among policymakers, stakeholders, and communities to realize the potential of circular-economy digitalization in accelerating decarbonization. By adopting digital opportunities in the waste sector based on China's experiences, Indonesia could accelerate decarbonization pathways in waste sector to accomplish its net-zero emission goals by 2060.

Determining the crude oil concentration changes as an essential factor in reservoir engineering, via proposed modified optical fiber sensor, offers a novel approach in oil production optimization. A highly sensitive optical fiber probe is fabricated via partially removing the cladding and coating the sensing part with zinc oxide/silver (ZnO/Ag) heterostructre layer. The ZnO outer layer has three configurations including nanoparticle, horizontally and vertically oriented nanorods. The fabricated optical fiber sensors are subjected to detect the crude oil concentration variations through detection of both wavelengths shift and intensity changes. The effect of ZnO outer layer shape, and the type of light source is used, on sensitivity of the probe is examined. Comprehensive investigation on shape dependent structural and optical properties of ZnO outer layer demonstrates that vertically oriented ZnO has larger surface area, higher average dispersion relation, better crystallinity, larger surface roughness and better adhesion (interaction) with crude oil molecules and these characteristics are responsible for its superior performance compare to other ZnO configurations. For the probe coated with vertically aligned ZnO nanorods when the infrared (IR) light source is used, the intensity and wavelength sensitivity of 0.044 dB/Δ%crude oil and 0.112 nm/Δ %crude oil are obtained respectively.

No abstract is provided for this article.

The employment of vanadium pentoxide (V2O5) as a photocatalyst has been widely utilized nowadays owing to its promising supercapacitor properties for photocatalysis applications. To the best of the author’s knowledge, there has yet to be a report on the investigation of Bisphenol A (BPA) removal from wastewater by using V2O5 photocatalyst. In this study, the V2O5 photocatalyst is synthesized using citric acid as a precursor via the calcination process. The properties of the synthesized V2O5 were evaluated in terms of porosity, surface morphology and composition elements, and its band gap value to well understand its’ behaviour and interaction with BPA pollutants. The abundant, irregular, and large pores sizes were observed and the low band gap (2.37 eV) obtained revealed that V2O5 was successfully synthesized as a potential photocatalyst when compared to previous studies. The photocatalytic performance of V2O5 towards BPA has provided a useful future reference in the field of photocatalysis research.

This work discusses the creation and assessment of rounded carbon membrane arranged from P84 co-polyimide mixes with Nanocrystalline cellulose (NCC). In light of earlier examinations, it defined the theory that rounded carbon membrane execution can be controlled by controlling the carbonization parameters. The focal point of this investigation is to acquaint compelling dip-coating strategies with deliver superior rounded carbon membrane. In light of the result of this examination, the coating carbonization cycle (1, 2, 3, and multiple times) has been distinguished as real effect on the separation productivity. Gas separation performance and transport instrument of the carbon membranes were enough assessed by single gas permeation of O 2 , and N 2 . In this exploration, use of 2-cycles of coating carbonization has brought about carbon membrane with the most elevated selectivity and O 2 penetrability which are 9.29±2.54 and 29.92±1.44 GPU, individually.