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61.
《Expert systems with applications》2006,30(3):527-534
The portfolio beta βp is quite an important coefficient in modern portfolio theory since it efficiently measures portfolio volatility relative to the benchmark index or the capital market. βp is usually employed for portfolio evaluation or prediction but scarcely for portfolio construction process. The main objective of this paper is to propose a portfolio algorithm that engages βp in its portfolio construction process and studies its strengths. Our portfolio algorithm termed as β-G portfolio algorithm selects stocks based on their market capitalization and optimizes them in terms of the standard deviation of βp. The optimizing process or finding optimal weights is done by the genetic algorithm. Our major findings on β-G portfolio algorithm are: (i) its performance depends on market volatility, i.e. it is expected to work well for a stable market whether it is bullish or bearish (ii) it tends to register outstanding performance for short-term applications. 相似文献
62.
《Computers & Mathematics with Applications》2006,51(3-4):661-666
Local asymptotic stability of nonlinear systems with real-parametric uncertainty or disturbance is one of the important problems in the control systems literature. In this paper, we investigate the problem of asymptotic stability for discrete-time nonlinear systems with time-varying disturbance. We assume that the disturbance vector is generated by an exosystem, which is neutrally stable. Thus, the disturbances that we consider include both constant and periodic signals. For this class of nonlinear systems with time-varying disturbance, we derive a necessary condition for local asymptotic stability of equilibria. As corollaries of our general result, we deduce the necessary condition obtained by Sundarapandian [1] for discrete-time nonlinear systems with constant real parametric uncertainty, and the necessary condition obtained by Lin and Byrnes [2] for discrete-time nonlinear autonomous systems. We illustrate our result with several examples. 相似文献
63.
Gopalu Karunakaran Govindhan Maduraiveeran Evgeny Kolesnikov Suresh Kannan Balasingam Lysov Dmitry Viktorovich Igor Ilinyh Mikhail V. Gorshenkov Manickam Sasidharan Denis Kuznetsov Manab Kundu 《JOM Journal of the Minerals, Metals and Materials Society》2018,70(8):1416-1422
We have synthesized NiCo2O4 nanoparticles (NCO NPs) using an ascorbic acid-assisted co-precipitation method for the first time. When NCO NPs are used as an anode material for lithium-ion batteries, the cell exhibits superior lithium storage properties, such as high capacity (700 mA h g?1 after 300 cycles at 200 mA g?1), excellent rate capabilities (applied current density range 100–1200 mA g?1), and impressive cycling stability (at 1200 mA g?1 up to 650 cycles). The enhanced electrochemical properties of NCO NPs are due to the nanometer dimensions which not only offers a smooth charge-transport pathway and short diffusion paths of the lithium ions but also adequate spaces for volume expansion during Li storage. Hence, this eco-friendly synthesis approach will provide a new strategy for the synthesis of various nanostructured metal oxide compounds, for energy conversion and storage systems applications. 相似文献
64.
B Sharmila S Bhuvaneshwari G Landlin 《Bulletin of Engineering Geology and the Environment》2021,80(8):6395-6413
Bulletin of Engineering Geology and the Environment - Long-term material dependency on natural resources has caused a heavy toll on the environment and biodiversity of natural systems. To explore... 相似文献
65.
A facile solid-state synthetic route was used to fabricate graphene oxide (GO) decorated with Ag nanoparticles. Ag/GO nanocomposites were prepared by reducing silver acetate with ascorbic acid in the presence of GO at ambient conditions. The characterization results showed that Ag nanoparticles with an average diameter of ~ 50 nm were well dispersed on the surface of GO nanosheets. Moreover, an application of the obtained Ag/GO nanocomposites as a catalyst in the reduction of 4-nitrophenol (4-NP) to 4-aminophenol by NaBH4 was demonstrated. The Ag/GO nanocomposites exhibited high activity and stability for the catalytic reduction of 4-NP. 相似文献
66.
《Ceramics International》2023,49(8):12408-12414
In the present investigation, nickel oxide nanoparticles (NiO) were biosynthesized utilizing an extract of Clerodendrum phlomidis leaves. Their size, phase study, and shape were investigated using a variety of research methods. In addition, we assessed the photocatalytic effects of NiO nanoparticles on the degradation of methylene blue (MB) and acid blue (AB) dyes. Throughout the research process, we found that these nanoparticles had extraordinary potential for photocatalysis when exposed to UV light. This is a 100% environmentally friendly method that makes no use of any harmful or poisonous solvents. High-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and ultraviolet–visible spectroscopy (UV–Vis) were used to analyze the biosynthesized NiO nanoparticles. The catalytic activity of the newly synthesized nanoparticles was evaluated by seeing how well they degraded dyes called methylene (MB) and acid blue (AB). Following the first-order reaction, kinetics was the photocatalytic effectiveness against the methylene blue (MB) and acid blue (AB) dyes, both of which exhibited a maximum degradation efficiency of 92% and 63%. Because of this, the biosynthesized NiO nanoparticles synthesized utilizing the extract of Clerodendrum phlomidis leaves have the potential to be used in photocatalytic applications. 相似文献
67.
《International Journal of Hydrogen Energy》2023,48(47):17827-17837
A novel Pd/PdO and hydrous RuO2 difunction-modified SiO2@TaON@Ta3N5 core-shell structured nano-photocatalyst was synthesized successfully, which displayed excellent photocatalytic activity for overall water splitting into H2 (473.52 μmol−1·g−1·h−1), about 2.86 times higher than unmodified SiO2@TaON@Ta3N5 (165.74 μmol−1·g−1·h−1), under the visible-light irradiation with the wavelength ≥420 nm, without any sacrificial agent, as well as excellent stability against photocorrosion. The apparent quantum yield (AQY) reaches to 0.253% under irradiation intensity of 12 mW cm−2 at 420 nm. The spatially separated Pd, PdO and RuO2 clusters were decorated on the Ta3N5 surface to construct local multi-heterojunctions, which were confirmed to enhance the light absorption capability, drive efficient separation of charge carriers and directional transfer, and promote surface redox reaction kinetics of HER and OER. The trace modification of metallic Pd clusters and TaN could mainly contribute to the significant decrease in the HER overpotential, while PdO exhibited a stronger contribution than RuO2 for OER catalytic activity. The synergetic mechanism of enhanced photocatalytic overall water splitting for hydrogen production was discussed in detail. Thus the combination of core-shell heterojunction construction and surface difunction modification provides a promising strategy for develop efficient all-in-one photocatalysts for solar overall water splitting. 相似文献
68.
《International Journal of Hydrogen Energy》2023,48(47):17838-17851
Sustainable energy innovation is spearheading the way to achieve decarbonisation through commercially viable and highly competitive renewable technologies for green hydrogen. Photocatalytic water splitting has received global attention, as it promotes the direct conversion of solar energy to chemical energy and hydrogen production. Lanthanum orthoferrite (LaFeO3) has been selected due to its narrow bandgap perovskite-oxides (ABO3) type nature, low cost and high chemical stability but it is limited with fast charge recombination. To circumvent its constraint of fast charge recombination, an efficient graphene-based nanocomposite has been prepared by employing reduced graphene oxide (RGO) nanosheets as charge separators for visible light driven photocatalytic water splitting. Here, we present a thorough physical and spectroscopic characterization of the Lanthanum orthoferrite/Reduced Graphene oxide (LaFeO3/RGO) nanocomposites, and investigate its photocatalytic and photoelectrochemical performance. The photocurrent density of the nanocomposites demonstrated ∼21 times higher in comparison to pure LaFeO3. The as-prepared nanocomposites have been successfully used as photocatalysts for H2 generation through water reduction under visible light. A significant enhancement in H2 generation has been recorded for nanocomposites (∼82 mmol g−1 h−1) as compared to that of bare LaFeO3 (∼9 mmol g−1 h−1) which is among the highest values obtained using noble-metal-free graphene-based photocatalytic nanocomposites. This work offers a facile approach for fabricating highly efficient 1D-2D heterostructure for photocatalysis application. 相似文献
69.
《International Journal of Hydrogen Energy》2023,48(62):24054-24073
This article investigates the effect of hydrogen induction on the characteristics of a CI engine fueled with the blend of camphor oil and diesel, along with diethyl ether (DEE) as an additive. The fuel sample was prepared by mixing 70% camphor oil with 30% diesel (C7D3) on a volume basis and then tested with 4 LPM (C7D3H4), 6 LPM (C7D3H6), and 8 LPM (C7D3H8) of hydrogen induction on the engine intake manifold. DEE was mixed at 10% and 20% with 90% and 80% of C7D3 on a volume basis and evaluated with 8 LPM of hydrogen induction; the resulting mixtures were designated as C7D3H8E10 and C7D3H8E20. The maximum thermal efficiency for C7D3H8E10 is 32.97%, with a minimum BSEC of 10.91 MJ/kgh, CO of 5.22 g/kWh, HC of 0.206 g/kWh, and smoke opacity of 39.6%. Hydrogen induction and increasing the quantity of hydrogen from 4 lpm to 8 lpm in the manifold increases the thermal efficiency to 32.63%. Further, it reduces the BSEC to 11.03 MJ/kgh, CO of 5.65 g/kWh, HC of 0.222 g/kW, and smoke opacity of 46.3%. NOx emissions were found to increase while increasing the hydrogen induction and with a 10% DEE addition to the C7D3 fuel. Further, raising the DEE from a 10%–20% ratio reduces the thermal efficiency and increases the BSEC, CO, HC, and smoke emissions. Overall, C7D3 in CI engines with 10% more DEE and hydrogen induction up to 8 LPM may be used efficiently. 相似文献
70.
《International Journal of Hydrogen Energy》2023,48(73):28289-28314
The ever-increasing energy demand, depleting fossil fuel reserves, and rising temperatures due to greenhouse gas emissions have necessitated the transition towards the generation of green and clean energy through renewable energy sources. Solar energy is one such renewable energy source that has received significant attention owing to its abundance and inexhaustibility. However, solar energy alone cannot replace fossil fuels in the energy portfolio. There exists a need to develop another clean energy source that can potentially act as an alternative to conventional fuels. Hydrogen proves to be an ideal candidate in this domain and can be sustainably generated by water electrolysis by powering the electrolyzer using solar energy. The hydrogen thus synthesized has net zero carbon emissions and is a suitable asset for decarbonizing the environment. This review encompasses the generation of hydrogen using PV-Electrolyzer systems and addresses the challenges associated with the same. Overcoming these drawbacks can ensure a strong position for hydrogen as an alternative fuel in the energy infrastructure. By employing electrolyzers that are fueled by renewable energy and then using that hydrogen to feed a fuel cell, this study aims to clarify the potential and constraints of producing green hydrogen. Since this area of research has not yet been fully investigated, a review article that enables and encourages academics to develop original solutions is urgently needed. 相似文献