19672 research outputs found
Sort by
Reuse of Selected Lignocellulosic and Processed Biomasses as Sustainable Sources for the Fabrication of Nanocellulose via Ni(II)-Catalyzed Hydrolysis Approach: A Comparative Study
No full textThis study investigates for the first time the feasibility of isolating nanocellulose from several selected feedstocks via a novel Ni(II)-hydrolysis process, including lignocellulosic biomasses (oil palm trunk, banana peel and coconut husk) and processed biomasses (newspaper, tissue paper and cotton linter), with an obtained gravimetric yield ranging from 59.6 to 86.2%. The isolation of nanocellulose products from these selected feedstocks was verified by the successive removal of most of their non-cellulosic components (lignin and hemicellulose) and cellulose amorphous regions, the increase in the crystallinity index and the nanoscale of the individual crystals. Most importantly, the resultant nanocellulose products rendered better thermal stability than that of corresponding original sources, which are highly potential to be utilized as the new renewable sources of reinforcement materials with potential applications in bio-nanocomposites and thermoplastics. Therefore, this work proves the viability of direct production of nanocellulose from a variety of cellulosic sources by using Ni(II)-based transition metal salt catalyst. The results suggested that the concept of waste to wealth could be well executed from the obtained nanocellulose, which are greatly potential for various industrial applications
Is Graphitic Silicon Carbide (Silagraphene) Stable?
No full textGraphene is considered to be the most likely candidate for the postsilicon era; however, the problem with its zero band gap is challenging to overcome. A close relative of silicon, silicon carbide is expected to have a stable 2D polymorph which happens to be a wide-gap semiconductor. Unfortunately, the so-called silagraphene has proven to be elusive. To date, neither theoretical nor experimental studies have been conclusive. Here, we employ computational methods to determine the stable arrangements of silagraphene and establish their accurate band structure. We also experimentally validate our models by preparing and characterizing a number of graphitic features. Silagraphene exhibits a wide spectrum of optoelectronic properties (360-690 nm) as well as an unusual band structure with highly anisotropic transport properties, which originates from its nondispersive band near its K-point. This feature makes direct-indirect gap crossover extremely sensitive to ambient conditions, making silagraphene suitable for a range of sensors
Predicting the adoption of cloud-based technology using fuzzy analytic hierarchy process and structural equation modelling approaches
No full textWith the emergence of cloud-based technology, personalized learning mechanism has increasingly become a fundamental requirement for most learning systems. This study aimed to identify the key factors that influence user adoption of cloud-based collaborative learning technology in the educational context. Grounded on the Unified Theory of Acceptance and Use of Technology (UTAUT), personalization construct was linked to the behavioral intention, performance expectancy and effort expectancy. This research applied a new methodological approach combining both Fuzzy Analytic Hierarchy Process (FAHP) and Structural Equation Modelling (SEM) to determine the relative weight and importance of the factors as well as to test the proposed hypotheses in the research model. Using a survey questionnaire, data was collected from 150 students of four Malaysian public universities. The findings of FAHP demonstrated that performance expectancy, social influence, and personalization were the most important factors predicting behavioral intention to adopt cloud-based collaborative learning technology from experts’ point of view. The results of the SEM showed that users’ behavioral intention was significantly influenced by performance expectancy, effort expectancy, social influence and personalization. Although, personalization performed a direct influence on behavioral intention, its indirect influence through performance expectancy and effort expectancy was also considerable. This study and its findings can serve as a baseline by which cloud service providers, ministry of education, and educational institutions can make strategic and strong decisions about adoption of cloud-based technology in educational environments
Multichannel Long-Range Surface Plasmon Waveguides for Parallel Biosensing
No full textTwo multichannel long-range surface plasmon waveguide structures are presented for parallel biosensing applications. The required ancillary passive optical elements are modeled and validated via comparisons with measurements to find good designs for the multichannel structures. The structures were fabricated as gold stripes embedded in CYTOP claddings with the fluidic channels defined via etching. The two multichannel structures are enabled using either a triple coupler or a corporate feed in cascade with an array of sensing waveguides. We demonstrate bulk and protein sensing for each channel comparable in performance to a single straight waveguide biosensor. Multiple channels are useful for parallel sensing, referencing, and common noise rejection
On-Chip Meander Line N-Well Resistor with Shielded Ground Conductor for Q-Factor Improvement
No full textThe on-chip meander line n-well resistor with a shielded ground conductor inserted parallel between the meander line on the silicon substrate is studied. The new design configuration concept with the shielded ground conductor improved the Q factor compared to those without the shielded ground conductor operating at high frequency. It was confirmed that the design configuration for the shielded ground conductor with a larger coverage area and increasing the number of parallel with the meander signal line was significant in improving the Q-factor performance operating at high frequency. Using this improvement method, the Q-factor value for proposed design meander line n-well structure with shielded ground conductor at 2 µm width in two T shapes has improved around 8% to 9% at 8, 9, and 10 GHz and reduced the parasitic mutual capacitance by 49.35 fF at 10 GHz when compared to the conventional structure of meander line n-well resistors. Shielded ground conductor technique is effective due to reduction of parasitic mutual capacitance. The resulting simulation of the return loss was improved using the shielded ground conductor method, but has poor of insertion loss, due to the skin effect. Overall, it has better performance compared to other designs because it has had significant improvement for Q factor to beyond 4 GHz and better return loss for all the range of frequency
Steam Influence and Effect of Oxidant Amount on Propane Oxidation over Multi Metal Oxide Catalyst Using High-Throughput Experiment
No full textThe high-throughput experimentation technique was used to verify the testing conditions due to the effects of catalyst structure modifications and/or due to reaction parameter variation in parallel. In this paper, the design of experiment and catalytic results are discussed in the development of selective oxidation catalyst, to demonstrate the importance and versatility of such technology. It is used for the automated parallel testing of selective oxidation of propane to acrylic acid over some types of multi metal oxide catalysts. The catalysts used for performance test were Mo (molybdenum), cat-1 (unsupported Mo1V0.3Te0.23Nb0.125O), and cat-2 (supported Mo1V0.3Te0.23Nb0.125O). All catalysts were dried using spray drier. The effect of some reaction parameters, such as the amount of oxidant, presence of steam and reaction temperature was also investigated during the test. The configuration of the ‘nanoflow’ is shown to be suitable to screen catalytic performance. The results obtained gave very good reproducibility
Income targets and poverty of rubber smallholders in four states of Malaysia
No full textBoth rubber and oil have contributed significantly to Malaysia’s revenues and job creations especially for those in the rural areas. Malaysia now stands at third after Thailand and Indonesia in natural rubber production. However, the country’s natural rubber productivity began to decline since late 2011 and would probably deteriorate through 2016 as consumption growth weakens in China – the largest importer, curbing prices of the raw material used in everything from tyre to medical gloves and condoms. The declining rubber price has moved the smallholders who mostly live in rural areas into serious poverty. This has led the smallholders, who sustain latex production, to suffer and find alternative jobs to sustain. This has dampened the government’s intention to ensure smallholders earn at least RM2,500 per month by 2015 and further to RM4,000 by 2020. The key objectives of this paper are to determine the poverty level, whether this policy has been met, and the impact of the reducing price of the commodity on the smallholders’ spending patterns. The study finds a large proportion of this group fall into the hardcore poverty category, which deviates very much from the national poverty levels pronounced by the government. More needs to be done to assist this impoverished group
Purification, characterization, mode of action, and enhanced production of Salivaricin mmaye1, a novel bacteriocin from Lactobacillus salivarius SPW1 of human gut origin
No full textBackground: Emergence of antibiotic resistance among pathogenic and food spoilage bacteria such as Staphylococcus aureus, Micrococcus luteus, Streptococcus pyogenes, Streptococcus sanguinis, Streptococcus mutans, Bacillus cereus, and Listeria monocytogenes triggered the search for alternative antimicrobials. An investigation aimed at purifying, characterizing, elucidating the mode of action, and enhancing the production of salivaricin from Lactobacillus salivarius of human gut origin was conducted. Results: Salivaricin mmaye1 is a novel bacteriocin purified from L. salivarius isolated from human feces. It is potent at micromolar concentrations and has a molecular weight of 1221.074 Da as determined by MALDI-TOF mass spectrometry. It has a broad spectrum of antibacterial activity. Salivaricin mmaye1 showed high thermal and chemical stability and moderate pH stability. The proteinaceous nature of salivaricin mmaye1 was revealed by the complete loss of activity after treatment with pepsin, trypsin, α-chymotrypsin, protease, and proteinase. Salivaricin mmaye1 is cell wall associated, and adsorption–desorption of the bacteriocin from the cell wall of the producer by pH modification proved successful. It exhibited a bactericidal mode of action mediated by pore formation. Its biosynthesis is regulated by a quorum sensing mechanism. Enhanced production of salivaricin mmaye1 was achieved in a newly developed growth medium. Conclusions: A novel, cell wall adhering, highly potent bacteriocin with a broad spectrum of inhibitory activity, membrane-permeabilizing ability, and enhanced production in a newly constituted medium has been isolated. It has a quorum sensing regulatory system and possesses interesting physicochemical characteristics favoring its future use in food biopreservation. These findings pave the way for future evaluation of its medical and food applications
Implementation of surface modified carbon cloth electrodes with biochar particles in microbial fuel cells
No full textMicrobial fuel cells (MFC) are bioelectrochemical reactors that convert chemical energy in organic substrates to electrical energy through catalytic reactions of microorganisms. The relationship between microorganisms and electrodes plays a vital role for effective functioning of an MFC. The physical and chemical properties of the electrodes are more crucial for a feasible MFC performance. Plain Carbon cloth (CC) and surface modified CC with four different sizes of Biochar (BC) particles such as 2 mm BC< 2, BC2-4, BC4-6, and BC6-10 were employed as anode electrodes in dual-chambered MFCs and their performance was compared. Results showed that the electrode with BC< 2 enhanced the MFC performance to with power density of 312 mWm−2 and BC6-10 facilitated the maximum COD degradation performance of 77% in the MFC both due to electrode properties like high porosity and large surface area. This study in general is a proof that BC has high feasibility for usage in MFC electrode modification studies
Moderating role of organisational learning and firm size on risk management maturity in construction firms
No full textBackground: It is not known whether organisational practice of learning and risk management maturity (RMM) varies based on firm size. Literature in the construction field lacks empirical studies on intervening influence of firm size on RMM. Objectives: This study aims to determine the significant factors influencing RMM by considering four dimensions of organisational learning (OL): information acquisition, knowledge dissemination, shared interpretation and organisational memory. Method: We tested the theoretical model in construction companies in Kuala Lumpur and Selangor states, Malaysia. There were 1000 questionnaires dispatched by mail and email to managers in the targeted firms. The component-based approach, also known as the partial least square (PLS) method, was used for data analysis. Results: Hierarchical regression analysis affirmed the influence of ten variables of OL on RMM while controlling the influence of firm size. Regardless of the firm size, the identified factors of OL can play an important role in enhancing the ability of construction organisations to attain better risk management practice. Conclusion: Construction firms seeking higher RMM should consider OL practices. The identified ten factors of OL are considered the vehicle to move the organisations to a new level of maturity. Particularly, firms should focus on two aspects of OL: information acquisition and shared interpretation. It can be deduced, therefore, that the more a firm acquires and interprets information related to project risk, the higher level of RMM the firm can achieve. In addition, effective learning through information gathering and interpretation could have a positive impact on risk management practices