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21.
Zhaofei Wen Guofan Shao Zakaria A. Mirza Jilong Chen Mingquan Lü 《International journal of remote sensing》2013,34(16):4195-4212
The presence of shadows in optical satellite images limits the application of remote-sensing technology. It is important to restore shadow radiance information for improving information extraction from remote-sensing images. Several shadow-restoration methods have been developed using complex statistical relationships between shadowed areas and their nearby sunlit areas. In this study, a simple shadow-restoration approach was proposed based on the surface reflectance equality relationship (RER) under the assumption that the surface reflectance of a feature in the shadowed area is equal to that of the same feature in the nearby sunlit area. This approach reduces the number of parameters, thus reducing the error propagated by the uncertainties of extra parameters. The new RER method was tested with three multispectral images with different shadow features. By comparing RER with the widely used mean and variance transformation, the RER was shown to be capable of restoring the image colours, texture, tone, and brightness of the shadowed areas to a visually satisfactory level. Quantitative analysis suggests that RER can help to restore the reflectance of shadow features accurately and has robust performance for a variety of land-surface types. Moreover, RER can be effectively used to restore the spectral shape information of shadow features, which is particularly important when applying RER to the restoration of multispectral imagery for the purpose of image classification. 相似文献
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Scheduling plays a vital role in ensuring the effectiveness of the production control of a flexible manufacturing system (FMS). The scheduling problem in FMS is considered to be dynamic in its nature as new orders may arrive every day. The new orders need to be integrated with the existing production schedule immediately without disturbing the performance and the stability of existing schedule. Most FMS scheduling methods reported in the literature address the static FMS scheduling problems. In this paper, rescheduling methods based on genetic algorithms are described to address arrivals of new orders. This study proposes genetic algorithms for match-up rescheduling with non-reshuffle and reshuffle strategies which accommodate new orders by manipulating the available idle times on machines and by resequencing operations, respectively. The basic idea of the match-up approach is to modify only a part of the initial schedule and to develop genetic algorithms (GAs) to generate a solution within the rescheduling horizon in such a way that both the stability and performance of the shop floor are kept. The proposed non-reshuffle and reshuffle strategies have been evaluated and the results have been compared with the total-rescheduling method. 相似文献
24.
Manel Nourine Moulai Karim Boulkadid Sabri Touidjine Elamine Louafi Hamdane Akbi Hamoud Abdelali Moulay Yahia Zakaria Samir Belkhiri 《Propellants, Explosives, Pyrotechnics》2024,49(5):e202300274
In this investigation, we successfully synthesized a hybrid material, N-rGO@Fe2O3, via a one-step hydrothermal process, comprising nitrogen-doped reduced graphene oxide and α-Fe2O3. Thorough characterization using diverse analytical methods validated its structure. Employing this hybrid composite as a catalyst, we studied its efficacy in the catalytic thermal decomposition of ammonium nitrate (AN). The N-rGO@Fe2O3/AN composite was prepared using a recurrent spray coating method with 3 % mass of the hybrid material. Thermo-gravimetric (TG) and differential scanning calorimetric (DSC) analyses were employed to investigate the catalytic effect. Computational assessment of Arrhenius parameters was conducted through isoconversional kinetic approaches. Results from the kinetic analysis allowed the determination of the critical ignition temperature. Furthermore, calorific values for pure AN and N-rGO@Fe2O3/AN were measured using an oxygen calorimetric bombe, revealing a 41 % reduction in activation energy barrier and a lowering of the critical ignition temperature from 292 °C to 283 °C upon incorporation of the hybrid material. Notably, the surface modification of AN with N-rGO@Fe2O3 resulted in an increase of 1440 J/g in the observed calorific values. These findings highlight the potential of N-rGO@Fe2O3 as an effective catalyst, offering promising implications for applications in enhancing ammonium nitrate thermal decomposition. 相似文献
25.
Direct ethanol fuel cells (DEFCs) offer a high degree of design flexibility, ranging from a single cell to a massive multi-cell that can be used in various applications, including portable devices, transportation, and stationary applications. Unfortunately, the most significant barrier to the commercialization of DEFCs is getting low-cost and ethanol permeability, high conductivity performance, and extended durability of polymer electrolyte membranes, as key components that highly influence the overall performance. In this paper, the recent progress in developing the polymer electrolyte membrane for the application of DEFCs has been comprehensively reviewed. Focusing on an updated modification of polymeric materials in the last 5 years, including Nafion-based membrane, polyvinyl alcohol-based membrane, polybenzimidazoles-based membrane, chitosan-based membrane, and sodium alginate-based membrane, as well as factors and challenges that affected the performance of polymer electrolyte membranes have been discussed, including the main characterization, catalyst selection, cell design, and work in membrane and cell performance of DEFCs. All discussion addresses the strategy to improve the performance of polymer electrolyte membranes in DEFCs in order to penetrate the commercialization stages. 相似文献
26.
Direct ethanol fuel cells (DEFCs) emerge as the new research energy field since fast production of electricity, high efficiency conversion, and simple fabrication process. The production cost, conductivity properties, and ethanol permeability of membrane were the main problem that limited the DEFC performance and commercialization. In this study, a low cost, good ionic conductivity and low ethanol permeability of an anion exchange membrane based on incorporation KOH‐doped quaternized poly(vinyl alcohol) (QPVA) membrane (designed as QPVA/KOH) is synthesized and cross‐linked with glutaraldehyde solution. The membrane is expected to cut the production cost and enhance the performance. In this work, an optimum of alkali‐doped concentration has influence the membrane performance. The membrane has reveal high chemical stability even doped with 8‐M KOH solution in 100°C. The morphology of membranes remained unbreakable and achieved high range of ionic conductivity (~10?2 S cm?1). The membranes present maximum ionic conductivity 1.29 × 10?2 S cm?1 at 30°C and 3.07 × 10?2 S cm?1 at 70°C. The ethanol permeability of membrane is lower compared with the commercial membranes. Power density of alkaline DEFCs with platinum‐based catalyst by using cross‐linked QPVA/KOH membrane is 5.88 mW cm?2, which is higher than commercial membranes at 30°C temperature. At 70°C, power density has increased up to 11.28 mW cm?2 and significantly increased up to 22.82 mW cm?2 via the nonplatinum‐based catalyst. Moreover, according to the durability test, the performance of passive alkaline DEFC by using cross‐linked QPVA/KOH membrane has maintained at 36.2% level. With such efficiency, the stack current density has been able to stay above 120 mA cm?2 for over 1000 hours, at 70°C. 相似文献
27.
Consumption of methanol and ethanol as a fuel in the passive direct fuel cells technologies is suitable and more useful for the portable application compared with hydrogen as a preliminary fuel due to the ease of management, including design of cell, transportation, and storage. However, the cost production of commercial membrane is still far from the acceptable commercialization stage. Based to our previous works, the low cost of cross‐linked sodium alginate (SA) polymer electrolyte bio‐membrane shown the virtuous chemical, mechanical, and thermal characterization as polymer electrolyte membrane in the direct methanol fuel cells (DMFCs). This study will further the investigation of cross‐linked SA polymer electrolyte bio‐membrane performance in the passive DMFCs and the passive direct ethanol fuel cells (DEFCs). The experimental study investigates the influence of the membrane thickness, loading of catalysts, temperature, type of fuel, and fuel concentration in order to achieve the optimal working operation performances. The passive DMFCs is improved from 1.45 up to 13.5 mW cm?2 for the maximum peak of power density, which is obtained by using 0.16 mm as an optimum thick of SA bio‐membrane that shown the highest selectivity 6.31 104 S s cm?3, 4 mg cm?2 of Pt‐Ru as an optimum of anode catalyst loading, 2 mg cm?2 of Pt at the cathode, 2M of methanol as an optimum fuel concentration, and an optimum temperature at 90°C. Under the same conditions of cells, the passive DEFCs are shown to be 10.2 mW cm?2 in the maximum peak of power density with 2M ethanol. Based on our knowledge, this is the first work that reports the optimization works of performance SA‐based membrane in the passive DMFCs via experimental studies of single cells and the primary performance of passive DEFCs using the SA‐based membrane as polymer electrolyte membrane. 相似文献
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A vast number of publications have investigated the application of electrocoagulation (EC) process in heavy metal ions removal from wastewaters. Most of these studies were simple lab-scale using synthetic wastewater with the absence of holistic and systematic approach to consider the process complexity. This comprehensive review considers the fundamental aspects of EC processes such as mechanisms, kinetic models, and isotherm models used by different researchers. Furthermore, the impact of the main design and process operational parameters on the removal efficiency is discussed and analyzed. Many concluding remarks and perspectives are stated to give insights for possible future investigations. 相似文献
30.
R. Zakaria W. Kam Y. S. Ong S. F. A. Z. Yusoff H. Ahmad Waleed S. Mohammed 《Journal of Modern Optics》2017,64(14):1443-1449
This paper describes simulation and experimental methods for designing a D-shaped surface plasmon resonance (SPR) fibre sensor. The sensor consists of two set-up approaches. Finite element method is used in simulation on the fibre sensor device. Two experimental methods for detecting relative intensity are used by varying the wavelength of the optical signal sources and the thickness of gold layer coated on the D-shaped fibre. In the first method, the sensor device works by detecting the relative intensity of two optical signal sources having different wavelengths. In the second set-up, the relative intensity between two D-shaped fibres coated with different thicknesses of gold is measured when a single signal source is launched at the input. The difference in intensities of the signal outputs is used to estimate the refractive index at the sensing region. A prototype SPR D-shaped fibre sensor has been fabricated and the experimental results show good agreement with simulation. 相似文献