Preparation of composite activated carbon nanofibers (ACNFs) for adsorption of heavy metals

The objective of this study is to prepare a new and highly efficient nanomaterial for heavy metals adsorption. Owing to that, activated carbon nanofibers (ACNFs) from precursor polyacrylnitrile (PAN) and manganese oxide (MnO2) have been prepared via electrospinning process for removal of heavy metals (lead and cadmium) from aqueous solution. The PAN/MnO2-based ACNFs were characterized in term of its morphological changes, specific surface area and functional groups analysis using SEM, BET and FTIR analysis respectively. The results showed that the specific surface area (SSA) of the electrospun composite ACNFs was higher than the neat ACNFs which is 499m2/g as compared to 800m2/g. SEM analysis illustrated that composite ACNFs have more compact fibers with presence of MnO2 beads and smaller fiber diameter of 437.2 nm whereas neat ACNFs possessed more aligned nanofibers with average fiber diameter of 575.5 nm. From adsorption study, the removal of Pb (II) and Cd (II) using both ACNF/MnO2 and ACNFs were higher than the commercial GAC with the removal efficiency is 100% for Pb (II) and 97% for Cd (II). The high removal efficiency of ACNFs/MnO2 is attributed by its larger SSA, presence of functional groups that play role in adsorption process such as hyroxyl and carboxyl groups and the role of manganese oxide as adsorbent itself (Han,2006). This excellent adsorption performance of ACNFs exhibits the potential of this composite adsorbent to solve the environmental issue of heavy metal contamination

Effects of different loading of magnesium oxide on activated carbon nanofibers for methane adsorption

In the last few years, with the escalating world demand for energy, natural gas had been suggested as an alternative for replacing heavy fossil fuels as it produces cleaner combustion, less harmful and economical. Moreover, continuous world’s depending on fossil fuels such as crude oils, coals and heavy fuels has become a major concerned to the entire world as the excessive burning of these fuels produced harmful gases that leading to global warming. For this reasons, in this work, PAN- based activated carbon nanofibers (ACNFs) with various loading of magnesium oxide (MgO) (0, 5, 10, and 15 wt.%) were prepared for methane (CH4) adsorption. The nanofibers (NFs) were successfully produced via electrospinning process at optimize parameters. The resultant NFs underwent three steps of pyrolysis process which are stabilization, carbonization and activation at 275 oC, 600 oC and 800 oC, respectively. The ACNFs/MgO were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric (TGA) analysis, X-ray diffraction (XRD) analysis, Brunaeur, Emmett and Teller (BET) method and CH4 adsorption tests. The adsorption equilibrium of CH4 on ACNFs/MgO was measured using a static volumetric technique. Adsorption of CH4 on the ACNFs/MgO was conducted at 30 oC for pressures up to 4 bars. The equilibrium data were stimulated using the Freundlich and Langmuir isotherms, with both models having R2 > 0.98. The results on BET surface area showed the ACNFs loading with 15 wt.% MgO has the highest surface area of 1893.09 m2/g and it was assumed to be a major contributor for higher gas adsorption capacity. From these findings, it is believed that ACNFs/MgO will become a new adsorbent with great potential for gas adsorption and storage in the near future applications

Residents willingness to pay for conservation of green spaces and amenities at urban forest Bukit Nanas, Kuala Lumpur

Greenery plays a key role in urban ecosystems could generate a wide range of services and amenities. They provide residents with outdoor recreational opportunities and contacts with nature to nurture a harmonious people–environment relationship healthy living environment. Cities of Kuala Lumpur have a growing demand for green spaces, due to growth in populations, improved quality of life, increased leisure time, and rising environmental awareness and expectation. Unfortunately, the recent rapid pace of urban expansion and redevelopment have eradicated or degraded some existing urban green spaces and failed to preserve natural pockets and corridors in large-scale sprawling into green fields. The main aim of this study is to determine the willingness to pay (WTP) and the residents’ value of urban green space in Kuala Lumpur city. The results show that 60% of the residents are willing to pay between RM 2 to RM 5 per year for the conservation of the urban green space. The results also indicated that most of the respondents feel responsible towards the existing urban green space and concern towards amenity in Bukit Nanas Forest Reserve

Synthesis, antifungal activity and semi-empirical AM1-MO calculations of some new 4-oxo-4H-chromene derivatives

Some new antifungal agents have been prepared through reaction of 4-oxo-4H-chromene-3-carbaldehydes (1a,b) with some active primary amines (2a-e) and amides/thioamides (6a-d) in different conditions. Structures of the products were established on the basis of elemental analysis, IR, 1H NMR, mass spectra and semi-empirical AM1-MO calculations

Household’s willingness to pay for watershed protection services in Langat Basin, Selangor using contingent valuation method

The significance of having a payment scheme for ecosystem services (PES) for the purpose of watershed protection in order to develop a sustainable forest management is globally recognised. PES is an advanced financial tool to foster a platform for generating a source of income from ecosystem service users to ecosystem providers. More importantly, the involvement of households is vital for the successful implementation of PES programmes. Thus, this study aims to examine the willingness to pay for watershed protection services among households in the Langat Basin. Households around upstream, middle-stream and downstream segments of the Langat Basin were selected randomly to be studied and involved in face-to-face interviews. The Probit and Logit models in Contingent Valuation Method (CVM) were employed to assess household’s WTP towards watershed protection efforts of the Langat Basin. The mean for WTP of Upstream household is RM30.01 while middle-stream household’s WTP is RM33.07 compared to that of the downstream household, which is RM32.41. The households’ WTP shows an increasing trend from upstream to downstream households. These results offer a new insight and discernment between PES programmes and households’ WTP so as to develop a sustainable management for water-based ecosystem services

GaInNAs-based Hellish-vertical cavity semiconductor optical amplifier for 1.3 μm operation

Hot electron light emission and lasing in semiconductor heterostructure (Hellish) devices are surface emitters the operation of which is based on the longitudinal injection of electrons and holes in the active region. These devices can be designed to be used as vertical cavity surface emitting laser or, as in this study, as a vertical cavity semiconductor optical amplifier (VCSOA). This study investigates the prospects for a Hellish VCSOA based on GaInNAs/GaAs material for operation in the 1.3-μm wavelength range. Hellish VCSOAs have increased functionality, and use undoped distributed Bragg reflectors; and this coupled with direct injection into the active region is expected to yield improvements in the gain and bandwidth. The design of the Hellish VCSOA is based on the transfer matrix method and the optical field distribution within the structure, where the determination of the position of quantum wells is crucial. A full assessment of Hellish VCSOAs has been performed in a device with eleven layers of Ga0.35In0.65N0.02As0.08/GaAs quantum wells (QWs) in the active region. It was characterised through I-V, L-V and by spectral photoluminescence, electroluminescence and electro-photoluminescence as a function of temperature and applied bias. Cavity resonance and gain peak curves have been calculated at different temperatures. Good agreement between experimental and theoretical results has been obtained

Addressing our planetary crisis: Consensus statement from the presenters and International Advisory Committee of the Regional Action on Climate Change (RACC) Symposium held in conjunction with the Kyoto-based Science and Technology in Society (STS) Forum, 1 October 2021.

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Balancing Public Service And Profit Creation : Sustainability Case Of Amanah Ikhtiar Malaysia.

This study focuses into the sustainability of Amanah Ikhtiar Malaysia (AIM).That is one of the microcredit institutions which is establish in Malaysia.This study focuses on Tanah Merah Branch that located in city of Tanah Merah. One of their objectives is to reduce poverty in Malaysia among their communities through activities created by AIM to help the poor people and give them true picture in order to improve their skills in develop the business. Which institutions to sustain their operation and management is one of the barriers that institutions must faced it.The services of Amanah Ikhtiar Malaysia may provide an opportunity for people to choose which scheme is required to reduce their burden and also help them to survive. Because of AIM institutions become in order help the poor people, AIM will be more concerned with the welfare of their clients to ensure they archive what they want in doing business. Currently can be explained a service that is performed for the advantage of the general population or its institutions itself that called a public service. In AIM also,about the profit creation, it’s create from management charge which is,charges imposed by every loan made to the rates specified. Sustainability of this institution related on the efforts of AIM in providing a starting capital to start a business as well as ongoing capital to borrowers

Preoperative glioma grading by MR diffusion and MR spectroscopic imaging

Objectives: To assess the diagnostic accuracy of DW-MRI, ADC value, and MRS in preoperative glioma grading because of its importance in treatment planning. Patients and methods: A prospective study included 30 patients with gliomas, based on CT and cMRI findings, referred from Neurosurgery Department for DWI and MRS. Results were correlated with histopathological diagnosis after surgical resection. Results: ADC values were significantly higher in low grade gliomas relative to high grade ones. The lowest value was for GBM, 100% sensitivity, specificity, PPV and NPP in glioma grading. MRS revealed higher Cho/NAA and Cho/Cr ratios in high grade neoplasms and characteristic elevated lipid peak with statistical significant difference between low grade and high grade gliomas. MRS was more accurate than ADC value in detecting peritumoral infiltration of high grade gliomas, but there were no statistically significant differences between anaplastic and GBM in tumoral and peritumoral regions. Conclusion: DW-MRI had higher sensitivity, specificity and accuracy than cMRI and MRS in glioma grading while MRS is more accurate than ADC value in assessing peri-tumoral infiltration based on high metabolite ratios in peri-tumoral tissue for anaplastic glioma and GBM, but there were no statistically significant differences between high grade groups