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1.
El-Moursy Ali A. Sibai Fadi N. Rehman Jahanzeb Gouda Omar M. Gaber Abdelrahman T. Khedr Ahmed M. 《Wireless Personal Communications》2022,124(2):1525-1555
Wireless Personal Communications - The development of Smart Home Controllers has seen rapid growth in recent years, especially for smart devices, that can utilize the Internet of Things (IoT).... 相似文献
2.
Perimeter discovery in wireless sensor networks 总被引:1,自引:0,他引:1
In this paper, we focus on the perimeter detection problem using wireless sensor networks, as perimeter detection has a wide range of uses in several areas. We present a decentralized localized algorithm where sensor nodes determine if they are located along the perimeter of a wireless sensor network. Our proposed algorithm uses the location neighborhood information in conjunction with the Barycentric technique to determine if the sensor node enclosed by neighboring nodes, and consequently, if it is located within the interior of the wireless sensor network. We define performance metrics to analyze the performance of our approach and the simulation shows that the algorithm gives fairly accurate results. 相似文献
3.
The effect of Ag on the stationary and non-stationary anodic corrosion rates of PbSbCd and PbSb alloys in H2SO4 has been studied. Anodic polarization curves were constructed under galvanostatic and potentiostatic conditions. Optical microscopic examination and microprobe analysis of the alloys were conducted. The beneficial effect of Ag was ascribed to a delay in closure of pores in the initial PbSO4 film. The leaching out of Sb from the outermost layers and the simultaneous nucleation of PbSO4 and Ag2SO4 from supersaturated solutions in the pores is thus made possible. 相似文献
4.
The solid-solid interactions between nanosized pure and NiO-substituted ferric and titanium(IV) oxides have been investigated using XRD technique and microstructure studies, also magnetic properties were studied using vibrating samples magnetometer (VSM). The amounts of substituting Ni2+ were x = 0, 0.2, 0.4, 0.6, 0.8 and 1 mole. A mixture equimolar proportions of finely powdered Fe2O3 and TiO2 were mixed with NiO, ball milled, compressed at 250 kg/cm2 and fired at 1200 °C for 4 h.The obtained results showed that with substituting Ni2+ concentration x = 0 only Fe2TiO5 phase is present (∼80 nm) which showed a very small saturation magnetic flux density (Bs), remnant magnetic flux density (Br) and the maximum energy product (BH)max. By the addition of x = 0.2 NiO, new phases were observed NiTiO3 and NiFe2O4 of crystallite sizes 160 and 110 nm, respectively. By the increase of substituting Ni2+ concentration the NiTiO3 and NiFe2O4 phases increased on the expense of Fe2TiO5 up to x = 0.4, then the increase in substituting Ni2+ concentration led to a decrease in Fe2TiO5 and NiTiO3 while NiFe2O4 increases which results in a great improvement of magnetic properties.All samples exhibit a catalytic activity towards H2O2 decomposition and the values of rate constant increase with increasing amount of Ni2+ substituting. The most acidic active sites are shown by specimens substituted with x = 0 this concludes that H2O2 decomposition is not favored on acidic active sites. 相似文献
5.
Wireless sensor networks (WSNs) are composed of many low cost, low power devices with sensing, local processing and wireless communication capabilities. Recent advances in wireless networks have led to many new protocols specifically designed for WSNs where energy awareness is an essential consideration. Most of the attention, however, has been given to the routing protocols since they might differ depending on the application and network architecture. Minimizing energy dissipation and maximizing network lifetime are important issues in the design of routing protocols for WSNs. In this paper, the low-energy adaptive clustering hierarchy (LEACH) routing protocol is considered and improved. We propose a clustering routing protocol named intra-balanced LEACH (IBLEACH), which extends LEACH protocol by balancing the energy consumption in the network. The simulation results show that IBLEACH outperforms LEACH and the existing improvements of LEACH in terms of network lifetime and energy consumption minimization. 相似文献
6.
1.IntroductionThe fast developments in science and technologyneed materials with specific properties to satisfy the re-quirements of the area of application.Metallic oxidesare important class of compounds and among them,ferrites are most prominent by virtue of their spinelstructure with high thermodynamic stability,magneticproperties[1~3],and electrical conductivity[4~6]and cat-alytic activity[7~9]in addition to their resistance to cor-rosion and so they are used in telecommunication,per-manen… 相似文献
7.
Nanocrystallite iron oxide powders with different crystallite sizes were prepared by co-precipitation route. The prepared powders with crystallite size 75, 100 and 150 nm together with commercial iron oxide (250 nm) were tested for the catalytic oxidation of CO to CO2. The influence of different factors as crystallite size, catalytic temperature and weight of catalyst on the rate of catalytic reaction was investigated using advanced quadrupole mass gas analyzer system. It can be reported that the rate of conversion of CO to CO2 increased by increasing catalytic temperature and decreasing crystallite size of the prepared powders. The experimental results show that nanocrystallite iron oxide powders with crystallite size 75 nm can be recommended as a promising catalyst for CO oxidation at 500 °C where 98% of CO is converted to CO2. The mechanism of the catalytic oxidation reaction was investigated by comparing the CO catalytic oxidation data in the absence and presence of oxygen. The reaction which was found to be first order with respect to CO is probably proceeded by adsorption mechanism where the reactants are adsorbed on the surface of the catalyst with breaking OO bonds, then CO pick up the dissociated O atom forming CO2. 相似文献
8.
Cu0.5Zn0.5Fe2O4 nanocrystallite powders (average size 13 nm) were synthesized from Cu-Zn spent catalyst (fertilizers) industries and ferrous sulfate wastes formed during iron and steel making. Cu-Zn catalyst (22.4% Cu and 26.4% Zn) was chemically treated with sulfuric acid at temperature 80 degrees C for 1 hr for the complete dissolving of copper and zinc into sulfate solution, then the produced solution was mixed with stoichiometric ratio of ferrous sulfate and the mixture was chemically precipitated as hydroxides followed by hydrothermal processing. The parameters affecting the magnetic properties and crystallite size of the produced ferrites powder e.g., temperature, time, and pH were systemically studied. X-ray diffraction analysis was used in order to determine the average crystallite size and phase identifications of the produced powder. The magnetic properties were studied by vibrating sample magnetometry. The results showed that the average crystallite size of the powder decreased for the ferrites powder formed at 150 degrees C and then increased by increasing the temperature to 200 degrees C. Interestingly, the saturation magnetization (Bs), remanent magnetization (Br) and coercive force (Hc) were 25.03 emu/g, 0.71 emu/g, and 4.83 Oe, respectively at hydrothermal temperature 150 degrees C for 24 hr and changed to 16.38 emu/g, 0.3864 emu/g, and 5.2 Oe at 150 degrees C and 72 hr. The produced nanoferrite powders are used for studying the catalytic activity of CO conversion to CO2 at different temperatures, pH and times. The maximum conversion (82%) is obtained at temperature 150 degrees C for 24 hrs and pH 12. 相似文献
9.
Amina A Attia Badie S Girgis Soheir A Khedr 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2003,78(6):611-619
Two activated carbons were obtained from pistachio shells by impregnation with H3PO4 under standard conditions of acid concentration (50 wt%) and heat treatment at 773 K for 2 h. The soaking time was 24 and 72 h for the two samples before thermal pyrolysis. Analysis of the N2/77 K adsorption isotherms proved that both were highly adsorbing carbons with considerable microporosity, and that the prolonged contact with activant enhanced total porosity (surface area and pore volume) and increased the amount of mesoporosity. Adsorption isotherms of probe molecules, viz methylene blue (MB), rhodamine B (RB), phenol (P) and p‐nitrophenol (PNP), were determined at room temperature, from aqueous solutions. Both the Langmuir and Freundlich model adsorption equations show satisfactory fit to experimental data. Both carbons exhibit similar adsorption parameters irrespective of their porosity characteristics. The sequence of uptake per unit weight was: PNP > MB > RB > P. Low affinity towards phenol may be associated with its competition with water molecules which are more favourably attracted to the acid surface which has a high oxygen functionality. Preferred adsorption in the order PNP > MB > RB is proposed to be a function of carbon porosity, related to the increased molecular dimensions of the solutes. Adsorption from a binary mixture of equal concentrations of MB and RB showed reduced uptake for both sorbates in comparison to the single component experiments. RB removal surpasses that of MB in the binary test and may be attributed to lower water solubility and higher molecular dimensions. Copyright © 2003 Society of Chemical Industry 相似文献
10.
The role of normal and activated bentonite on the pelletization of barite iron ore concentrate and the quality of pellets 总被引:1,自引:0,他引:1
O. A.Mohamed M. E. H. Shalabi N. A. El-Hussiny M. H. Khedr F. Mostafa 《Powder Technology》2003,130(1-3):277-282
The essential parameters affecting the pelletization process of high barite iron ore concentrate were studied using the Egyptian normal and activated bentonite as binder materials. The metallurgical properties of green, dried and fired pellets were studied using chemical and X-ray analyses. The average strength of fired pellets 1.5% normal bentonite and fired 1300 °C for 25 min exceeded 200 kg/pellet. Using activated bentonite produced a lower kg/pellet value. Meanwhile, the productivity of green pellets decreased when the last binder was used. 相似文献