19672 research outputs found
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Nanosecond Pulse Generation with Silver Nanoparticle Saturable Absorber
No full textNanosecond pulse generation in an erbium-doped fiber laser (EDFL) passively mode-locked by a silver nanoparticle (SNP)-based saturable absorber (SA) is experimentally demonstrated. The SA is fabricated by depositing a nanosized SNP layer onto the surface of polyvinyl alcohol film through the thermal evaporation process. By inserting the SA into an EDFL cavity, stable mode-locked operation is achieved at 1561.5nm with the maximum pulse energy up to 52.3 nJ. The laser operates at a pulse repetition frequency of 1.0MHz with a pulse width of 202 ns. These results suggest that SNPs could be developed as an effective SA for mode-locking pulse generation. © 2019 Chinese Physical Society and IOP Publishing Ltd
Kinetics and Mechanism of Flexible Nanoparticles-Catalyzed Piperidinolysis of Anionic Phenyl Salicylate: Flexible Nanoparticles: CTABr/M2X/H2O (M2X = 4-MeOSaNa2, 3-, 4-MeSaNa2)
No full textApparent pseudo second-order rate constants, k X , for flexible nanoparticles, FNs, (CTABr/M 2 X/H 2 O)-catalyzed piperidinolysis of anionic phenyl salicylate, PSa − , at a constant [CTABr], 0.1 M piperidine (Pip) and temperature, were calculated from an empirical equation. CTABr = cetyltrimethylammonium bromide and X 2− = 4-methoxysalicylate (4-MeOSa 2− ) and 3-,4-methylsalicylate (3-,4-MeSa 2− ) with Sa 2− representing − O-C 6 H 3 CO 2 − . The values of k X /k 0 = μ measure the apparent rate enhancement due to FN catalysis for piperidinolysis of PSa − at a constant [CTABr] and temperature. The values of μ decrease with the increase in [CTABr] within the range of 5–15 mM. © 2019, Pleiades Publishing, Ltd
Oxidizing Effect of Ozonated-Water on Microbial Balance in the Oral Ecosystem
No full textApplication of ozone is recommended for sterilisation in dental procedures. This study explored the antimicrobial effect of 0.1 ppm ozonated-water on selected common oral commensals. Based on deviation of their growth curves pattern upon ozone treatment, the inhibitory effect of ozone was determined. SEM examination of the ozone-treated microbes recorded its possible morphological effect. Findings suggested a bacteriostatic action of ozone when microbes were treated at the early phase, while, it was bactericidal when treated during the active phase of the growth cycle. Hence, suggesting rinsing the oral cavity with ozonated-water at 0.1 ppm immediately after tooth brushing may suppress microbial growth and slow biofilm formation. While, rinsing on already developed biofilm may result in microbial cell lysis that halted microbial growth and reduce microbial population in the biofilm. Both justify the great potential of ozone (0.1 ppm) for use as antimicrobial agent for the control of biofilm development in the oral cavity. © 2019 College of Physicians and Surgeons Pakistan. All rights reserved
Comparison Study of Malaysian Driver Seating Position in SAEJ1517 Accommodation Model
No full textA key element in an ergonomically designed driver’s seat in a car is the correct identification of driver seating position and posture accommodation. Current practice by the automotive Original Equipment Manufacturer (OEM) is to utilize the Society of Automotive Engineering (SAE) J1517 standard practice as a reference. However, it was found that utilizing such guidelines, which were developed based on the American population, did not fit well with the anthropometry and stature of the Malaysian population. This research seeks to address this issue by comparing the SAE J1517 Model against Malaysian preferred driving position. A total of 62 respondents were involved for the driver seating position and accommodation study in the vehicle driver’s seat buck mockup survey and measurements. The results have shown that the Malaysian drivers prefer to sit forward as compared to the SAE J1517 Model and have shorter posture joint angle. This could significantly affect the design of the driver seat positions and layout of other driving elements, suggesting a need to reconsider its application, in particular for the Malaysian population. Copyright © 2019 SAE International
Influence of different morphology of carbon nanostructures on the structural and optical properties of decorated single crystalline hematite nanocubes for photoelectrochemical applications
No full textHematite (α-Fe2O3) is among one of the potential n-type metal oxide semiconductors that able to absorb wide range of visible spectrum and thus makes it a particularly attractive material to be used in solar energy conversion. In this work, facile hydrothermal approach was adapted to synthesis hybrid single crystalline cubic hematite decorated carbon nanostructures (α-Fe2O3/CNs) nanocomposites for photoelectrochemical (PEC) application. By harnessing the highly-exposed nature of CNs, it was used as a basal structure to anchor α-Fe2O3 semiconductor materials for enhanced light trapping to produce better PEC performance. α-Fe2O3 nanocubes were decorated on different CNs surface morphologies (namely globular- like CNs, caterpillar-like CNs, clustered caterpillar-like CNs, and granular-like CNs). High-resolution transmission electron microscopy reveals α-Fe2O3 were randomly distributed throughout the surface of CNs. Appreciating the unique structure of those hybrid nanostructures, the as-prepared hybrid α-Fe2O3/CNs nanocomposites exhibit improved light absorption and lower photocurrent onset potential as compared to pure CNs. The photocurrent density was determined to be in the range of 0.0199 to 0.1845 mA/cm2 at 1.23 V, where the α-Fe2O3/clustered caterpillar-like CNs showed the highest photocurrent density. Current study is believed to contribute to the field of materials science, particularly on the aspect of hybrid nanocomposites synthesis and PEC applications. © 2019 Elsevier B.V
Hikayat Seri Rama: Establishing the source
No full textPurpose of the study: The main aim of this paper is to establish the Tamil literary sources of the Hikayat Seri Rama. Various recensions of the Hikayat Seri Rama demonstrate the close identity between one text and the other which would seem to indicate that all these texts were apparently derived from some older versions of the Rama story, which was the common source of all the recensions. Methodology: The methodology employed in this article is qualitative in nature. It is library research based on the existing published materials. Four steps of Hermeneutics approaches have been employed to produce findings which are objective in nature. This research is aimed to contribute to the existing body of knowledge about the sources of Hikayat Seri Rama. Main findings: This study would enable us to appreciate the close similarity of motifs and episodes between HSR and the Rama story in Tamil tradition. The Rama story in Tamil folklore itself stands out as a great proof to manifest that the Tamil sources are predominant in Hikayat Seri Rama compared to any other sources. Applications of this study: This study will contribute to the existing body of knowledge and will enable one to appreciate the close cultural relationship between the Tamil and the Malay literary traditions. Hence, it provides a platform for the positive cultural as well as civilizational dialog between the two communities. Additionally, this article can also contribute to the comparative studies involving Indian and Malay literature. Novelty/Originality of this study: Literature reviews clearly show that there is no other similar study to this work conducted elsewhere. Hence, the originality of this study is established. Previous studies failed establish the source for the Hikayat Seri Rama as most of those studies ignored Tamil literary sources. This study managed to prove the source of Hikayat Seri Rama based on Tamil literary sources.. © 2019 Primrose Hall Publishing Group
Holmium based nanoseconds pulsed fibre laser generation in the 2-micron region
No full textWe demonstrate and compare nanoseconds pulse induced by a Holmium oxide PVA film (HOPF, 50 μm thick) and a Holmium-doped fibre (HDF, 8 cm long) saturable absorber (SA) in a Thulium doped-fibre laser (TDFL) cavity. The HOPF SA produced a nanoseconds pulse operating at 1960 nm wavelength, with a pulse width of 57 ns. On the other hand, the HDF SA produced a pulsed laser operating at 1963 nm wavelength, with a pulse width of 53 ns. The HDF SA established a slightly better maximum pulse energy of 0.87 nJ as compared to the HOPF SA with only 0.62 nJ. © 2019 Elsevier Gmb
Towards Sustainable Energy: A Systematic Review of Renewable Energy Sources, Technologies, and Public Opinions
No full textThe use of renewable energy resources, such as solar, wind, and biomass will not diminish their availability. Sunlight being a constant source of energy is used to meet the ever-increasing energy need. This review discusses the world's energy needs, renewable energy technologies for domestic use, and highlights public opinions on renewable energy. A systematic review of the literature was conducted from 2009 to 2018. During this process, more than 300 articles were classified and 42 papers were filtered for critical review. The literature analysis showed that despite serious efforts at all levels to reduce reliance on fossil fuels by promoting renewable energy as its alternative, fossil fuels continue to contribute 73.5% to the worldwide electricity production in 2017. Conversely, renewable sources contributed only 26.5%. Furthermore, this study highlights that the lack of public awareness is a major barrier to the acceptance of renewable energy technologies. The results of this study show that worldwide energy crises can be managed by integrating renewable energy sources in the power generation. Moreover, in order to facilitate the development of renewable energy technologies, this systematic review has highlighted the importance of public opinion and performed a real-time analysis of public tweets. This example of tweet analysis is a relatively novel initiative in a review study that will seek to direct the attention of future researchers and policymakers toward public opinion and recommend the implications to both academia and industries. © 2013 IEEE
Fabrication of photocatalyst MgO: CuO composite and enhancement of photocatalytic activity under UV light
No full textThe green synthesis of composites through biological entities such as natural plants, algae, bacteria, fungi, and viruses is regarded to be easy, fast, affordable, low-cost, and environmentally friendly. Therefore, the MgO:CuO composites were synthesized by eco-friendly synthesis method. The MgO:CuO composites were prepared from many fruits of PAGOB (Pomegranate, Apple, Grapes, Orange and Banana) peel extract. The present study is decolourization of methylene blue dye using UV light. The phase purity and crystallite size were characterized and confirmed by x-ray diffraction (XRD) studies. The maximum absorbance was obtained in the 200-800 nm regions with a prominent peak absorbance was observed by UV-vis spectrum. The corresponding band gap for MgO:CuO composite was calculated using Tauc's plot and was found to be 2.2 eV. The textural and surface morphological feature of the synthesized composites were characterized by High-resolution Scanning Electron Microscopy (HR-SEM) and elemental analysis of Composites was analyzed with the help of Energy Dispersive x-ray analysis (EDX). The influence of pH, dye concentration, amount of photocatalyst and intensity of light on the rate of photocatalytic reaction was observed. The results show that the degradation reached 89% under optimum conditions. The resulting MgO:CuO composites and exhibits highly efficient and excellent photocatalytic properties. This property can be utilized to degrade organic contaminants. This concept was shown by degrading methylene blue, which can be observed photometrically. © 2019 IOP Publishing Ltd
Hybrid ANN and Artificial Cooperative Search Algorithm to Forecast Short-Term Electricity Price in De-Regulated Electricity Market
No full textSmart grid has evolved into a viable platform for participants of electricity market to effectively regulate their bidding strategies based on demand-side management (DSM) models ascribed to its immense technological advancements in recent years. Reliability of system operation as well as capital cost investments can improve greatly with responsiveness of market participants. In this regard, efficient design, implementation, evaluation of numerous demand response measures and development of robust short-term price forecasting in the day-ahead transactions are of the utmost importance. Accuracy and efficiency of the day-ahead price forecasting process are complex challenges in deregulated electricity market. The unstable nature of electricity price compared to load series causes lower accuracy. Therefore, this research proposes a hybrid method for electricity price forecasting via artificial neural network (ANN) and artificial cooperative search algorithm (ACS). In parallel, a feature selection technique based on the combination of mutual information (MI) and neural network (NN) is developed in this study to select the input variables subsets, which have substantial impact on forecasting of electricity price. Actual data sets are collected from Ontario electricity market of the year 2017 for the verification of simulation results. Finally, the simulation results validated the premise of the proposed hybrid method through enhanced accuracy compared to the results acquired by implementing hybrid support vector machine (SVM) and hybrid ANN optimization methods. © 2013 IEEE