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181.
Mohamed Shaban Mostafa R. Abukhadra Ahmed Hamd 《Clean Technologies and Environmental Policy》2018,20(1):13-28
Glass was successfully recycled in the synthesis of mesoporous silica MCM-48 which was used as catalyst support for nickel oxide photocatalyst. The resulted products were evaluated using X-ray diffraction, scanning electron microscope and UV–Vis spectrophotometer. The precipitated nickel oxide is of Ni2O3 form and loading of it onto MCM-48 resulted in a reduction in the band gap energy from about 3.66 eV to about 2.4 eV. The role of MCM-48 as catalyst support for Ni2O3 in enhancing the adsorption capacity and photocatalytic properties of nickel oxide was evaluated through series of equilibrium studies and photocatalytic degradation of Congo red dye under visible light. Using of glass-based MCM-48 as catalyst support for Ni2O3 showed enhancing the adsorption capacity by 31.3 and 14.8% higher than the adsorption capacity of Ni2O3 and MCM-48, respectively. Also, the photocatalytic degradation percentage increased by about 67.3% relative to the Ni2O3 degradation percentage. The nature of MCM-48/Ni2O3 adsorption mechanism is chemisorption and occurs in multilayer form throughout the heterogeneous surface of the composite. The using of MCM-48 as support for Ni2O3 photocatalyst enhanced the adsorption capacity through increasing the total surface area. The loading process resulted in fixing of the Ni2O3 particles throughout the porous structure which producing more exposed active photocatalyst sites and active adsorption sites for the incident photons as well as preventing the nickel oxide particles from agglomeration. Based on the obtained results, supporting of Ni2O3 particles onto MCM-48 is promising active centers for the degradation of Congo red dye molecules. 相似文献
182.
Nadir Ouldhamadouche Amine Achour Raul Lucio-Porto Mohammad Islam Shahram Solaymani Ali Arman Azin Ahmadpourian Hamed Achour Laurent Le Brizoual Mohamed Abdou Djouadi Thierry Brousse 《材料科学技术学报》2018,34(6):976-982
Vanadium nitride(VN) was deposited by DC-sputtering on a vertically aligned carbon nanotube(CNTs)template for the purpose of nano-structuration. This led to the fabrication of hierarchically composite electrodes consisting of porous and nanostructured VN grown on vertically aligned CNTs in a nano-treelike configuration for micro-supercapacitor application. The electrodes show excellent performance with an areal capacitance as high as 37.5 m F cm~(-2) at a scan rate of 2 mV s~(-1) in a 0.5 MK_2SO_4 mild electrolyte solution. Furthermore, the capacitance decay was only 15% after 20,000 consecutive cycles. Moreover,the capacitance was found to increase with VN deposit thickness. The X-ray photoelectron spectroscopy analyses of the electrodes before and after cycling suggest that the oxide layers that form at the VN surface is the responsible for the redox energy storage in this material. Such electrodes can compete with other transition metal nitride based electrodes for micro-supercapacitors. 相似文献
183.
Korichi Meriem Kherfi Mohamed Lamine Batouche Mohamed Bouanane Khadra 《Multimedia Tools and Applications》2018,77(23):31115-31138
Multimedia Tools and Applications - Learning concepts from examples presented in user’s query and infer the other items that belong to this query is still a significant challenge for images... 相似文献
184.
This paper describes a stable adaptive motion/force control of uncertain nonholonomic mobile manipulator with the consideration of external force. As it is well known, unexpected external force makes the motion of the system unstable since there are no fixed points in the stationary coordinate. Here, a novel adaptive control scheme is utilized to estimate and compensate the unknown external force exerted to the end-effector even if the parameters of the system are uncertain. The important advantages of this approach are to achieve estimation without the requirement of force-sensing feedback and the knowledge of the system dynamic model. The update laws for the force and the parameters are derived from a Lyapunov function to guarantee the control system stability. Furthermore, a unified operational space dynamic formulation is presented to solve the problem of redundancy. As a result, the desired end-effector and platform trajectories are simultaneously tracked with a perfect coordination between the two subsystems. Therefore, the proposed controller proves that it can not only guarantee the stability, but also the tracking performance of the system in the task space. The effectiveness of the proposed algorithm is evaluated through extensive simulations and they demonstrate the stability, tracking trajectories and feasibility in estimating the external force and the dynamic uncertainties. 相似文献
185.
Khalili Amelia Ahmad Mohamed Zaharuddin Basri Mohd Ariffanan Mohd 《Microsystem Technologies》2019,25(10):3765-3777
Microsystem Technologies - In this paper a robust backstepping sliding mode controller is developed for tracking control of 2-DOF piezo-actuated micromanipulation system. The control approach is... 相似文献
186.
Hendawi Abdeltawab Gupta Jayant Liu Jiayi Teredesai Ankur Ramakrishnan Naveen Shah Mohak El-Sappagh Shaker Kwak Kyung-Sup Ali Mohamed 《The Journal of supercomputing》2019,75(12):8207-8230
The Journal of Supercomputing - In the current era of the Internet of Things (IoT), massive number of sensors are used in our daily lives. Sensors are everywhere around us. They exist in our homes,... 相似文献
187.
Faten Nasri Manel Zouari Mohamed Kharrat Maher Dammak Florence Vacandio Marielle Eyraud 《Transactions of the Indian Institute of Metals》2018,71(8):1827-1840
Zn and Zn–Ni alloy coatings were electrodeposited on mild steel from sulfate-based bath containing Sn as additive. The effect of Ni content on the microstructure, morphology, microhardness and the tribological behavior of these coatings were studied and discussed. Adding Sn in the sulfate bath had a significant effect on the surface morphology, particularly on the Zn–8 wt% Ni coatings. By increasing the Ni concentration from 8 to 14 wt%, the X-ray patterns showed that the phase structure of Zn–Ni alloy coatings was changed from η-phase Ni3Zn22 to γ-phase Ni5Zn21. The plastic deformation and delamination were found to be wear mechanisms for the investigated coatings. While the Zn–14 wt% Ni alloys had the best wear resistance, Zn films had the most severe wear volume loss and the highest friction coefficient. 相似文献
188.
An-Zhen Zhang Jian-Zhong Li Hong Gao Yu-Biao Chen Heng-Zhao Ma Mohamed Jaward Bah 《计算机科学技术学报》2018,33(2):366-379
Recently there is an increasing need for interactive human-driven analysis on large volumes of data. Online aggregation (OLA), which provides a quick sketch of massive data before a long wait of the final accurate query result, has drawn significant research attention. However, the direct processing of OLA on duplicate data will lead to incorrect query answers, since sampling from duplicate records leads to an over representation of the duplicate data in the sample. This violates the prerequisite of uniform distributions in most statistical theories. In this paper, we propose CrowdOLA, a novel framework for integrating online aggregation processing with deduplication. Instead of cleaning the whole dataset, CrowdOLA retrieves block-level samples continuously from the dataset, and employs a crowd-based entity resolution approach to detect duplicates in the sample in a pay-as-you-go fashion. After cleaning the sample, an unbiased estimator is provided to address the error bias that is introduced by the duplication. We evaluate CrowdOLA on both real-world and synthetic workloads. Experimental results show that CrowdOLA provides a good balance between efficiency and accuracy. 相似文献
189.
Design concepts of the Sectored Compact Space Reactor for Small power (SCoRe-S) have been developed for the avoidance of single-point failures in reactor cooling and energy conversion and a wide range of thermal powers. These modular, fast neutron spectrum, lithium cooled reactors with 16.0 cm thick BeO radial reflector are designed for at least +$2.00 hot-clean excess reactivity, and with a sufficient reactivity shutdown margin. They employ 157GdN additives in the UN fuel and a 0.10 mm thick coating of 157Gd2O3 on the outer surface of the reactor vessel to ensure that the bare reactors, when submerged in wet sand and flooded with seawater following a launch abort accident, remain at least ?$1.00 subcritical. In addition to identifying the smallest SCoRe-S concept that satisfies the design reactivity requirements, the benefit of using a lunar regolith as a supplementary reflector to decrease the thickness of the BeO radial reflector and hence, the launch mass of the SCoRe-S concepts for a lunar outpost is investigated. Calculations performed using MCNP5 confirmed that SCoRe-S7 with a 16 cm thick BeO reflector is the smallest to satisfy the stated reactivity requirements. Results also show that a lunar regolith reflector alone is inadequate for this reactor to achieve a critical state at the beginning of life. However, when the regolith is used in conjunction with a BeO reflector of a reduced thickness, this reactor not only becomes critical, but also satisfies the reactivity design requirements at a significantly reduced launch mass. Using a supplementary reflector of regolith decreases the thickness of the BeO reflector for the SCoRe-S7 from 16 cm to 8.0 cm, and to 5.7 cm for the SCoRe-S11 of the largest core. The resulting decreases in the launch mass of the SCoRe-S concepts are ~34% or 150–200 kg. 相似文献
190.
The frequency (10 - 107 Hz), temperature (303-363 K) or /and bias voltage (−2 to 2 V) dependence of the dielectric properties of 相似文献