Trust Index Based Fault Tolerant Multiple Event Localization Algorithm for WSNs

This paper investigates the use of wireless sensor networks for multiple event source localization using binary information from the sensor nodes. The events could continually emit signals whose strength is attenuated inversely proportional to the distance from the source. In this context, faults occur due to various reasons and are manifested when a node reports a wrong decision. In order to reduce the impact of node faults on the accuracy of multiple event localization, we introduce a trust index model to evaluate the fidelity of information which the nodes report and use in the event detection process, and propose the Trust Index based Subtract on Negative Add on Positive (TISNAP) localization algorithm, which reduces the impact of faulty nodes on the event localization by decreasing their trust index, to improve the accuracy of event localization and performance of fault tolerance for multiple event source localization. The algorithm includes three phases: first, the sink identifies the cluster nodes to determine the number of events occurred in the entire region by analyzing the binary data reported by all nodes; then, it constructs the likelihood matrix related to the cluster nodes and estimates the location of all events according to the alarmed status and trust index of the nodes around the cluster nodes. Finally, the sink updates the trust index of all nodes according to the fidelity of their information in the previous reporting cycle. The algorithm improves the accuracy of localization and performance of fault tolerance in multiple event source localization. The experiment results show that when the probability of node fault is close to 50%, the algorithm can still accurately determine the number of the events and have better accuracy of localization compared with other algorithms

Two ultraviolet radiation datasets that cover China

Ultraviolet (UV) radiation has significant effects on ecosystems, environments, and human health, as well as atmospheric processes and climate change. Two ultraviolet radiation datasets are described in this paper. One contains hourly observations of UV radiation measured at 40 Chinese Ecosystem Research Network stations from 2005 to 2015. CUV3 broadband radiometers were used to observe the UV radiation, with an accuracy of 5%, which meets the World Meteorology Organization's measurement standards. The extremum method was used to control the quality of the measured datasets. The other dataset contains daily cumulative UV radiation estimates that were calculated using an all-sky estimation model combined with a hybrid model. The reconstructed daily UV radiation data span from 1961 to 2014. The mean absolute bias error and root-mean-square error are smaller than 30% at most stations, and most of the mean bias error values are negative, which indicates underestimation of the UV radiation intensity. These datasets can improve our basic knowledge of the spatial and temporal variations in UV radiation. Additionally, these datasets can be used in studies of potential ozone formation and atmospheric oxidation, as well as simulations of ecological processes

The effect of composite reducing agent on the reduction process and the tail gas of carbon-containing pellets

In order to explore a reasonable way for the efficient utilization of coal resources in the ironmaking process. In this paper, lignite and bituminous coal are used as reducing agents, and two types of vanadium-titanium magnetite composite reducing agent pellets are prepared for different content ratios and mixed forms of the two coal powders. Under the simulated rotary kiln pre-reduction conditions, the influence of the ratio and mixing of pulverized coal on the metallization rate and tail gas composition of the reduction process was explored. The results show that increasing the proportion of high volatile lignite is beneficial to the reduction of pellets and can obtain pellets with a higher metallization rate. Under the new pre-reduction process conditions of the rotary kiln, the vanadium-titanium magnetite double-layer pellet with 75wt% lignite inside and 25wt% bituminous coal outside has the highest metallization rate of about 76%. At the same time, this new type of composite reducing agent pellets reduced gas emissions. This pellet is of great significance to the coal-based ironmaking process

A Mechanically Controlled Switchable Wideband Frequency–Selective Rasorber/Absorber

A mechanically controlled switchable wideband frequency–selective rasorber/absorber, with the transmission window inside the absorption band, based on a frequency–selective surface and a rotatable metal plate, is presented in this paper. The absorption of the switchable rasorber/absorber is over 90%, from 3.9 GHz to 11.77 GHz, when the rotatable metal plate is parallel to the rest of the layers, and its transmission coefficient can reach up to 0.62 at 11.6 GHz, with the rotatable metal plate perpendicular to the rest of the layers. The mechanism of wideband absorption and transmission are explained by monitoring and analyzing the surface current distribution at the absorption and transmission frequencies. The control method is simple, reliable and accurate. It has application value in communication and radar stations

A Mechanically Controlled Switchable Wideband Frequency–Selective Rasorber/Absorber

A mechanically controlled switchable wideband frequency–selective rasorber/absorber, with the transmission window inside the absorption band, based on a frequency–selective surface and a rotatable metal plate, is presented in this paper. The absorption of the switchable rasorber/absorber is over 90%, from 3.9 GHz to 11.77 GHz, when the rotatable metal plate is parallel to the rest of the layers, and its transmission coefficient can reach up to 0.62 at 11.6 GHz, with the rotatable metal plate perpendicular to the rest of the layers. The mechanism of wideband absorption and transmission are explained by monitoring and analyzing the surface current distribution at the absorption and transmission frequencies. The control method is simple, reliable and accurate. It has application value in communication and radar stations

Influence of Parameters on the Pre-Reduction Process of Vanadium-Titanium Magnetite Carbon-Containing Composite Pellets in Rotary Kiln

A novel smelting reduction process called pre-reduction in rotary kiln and total oxygen melting pool is a promising route to reduce environmental pollution from the ironmaking industry. In this paper, the process parameters and appropriate efficiency of reduction in the pre-reduction process of the rotary kiln were investigated via the detection of the metallization rate, phase composition, and internal morphology of the product combining with the analysis of the off-gas. The results indicated that the parameters of reduction temperature, reduction holding time, and coal ratio have a remarkable influence on the metallization rate. The reduction temperature has the most significant effect, followed by the reduction time and the coal ratio. Furthermore, under the condition of reduction temperature 1000 °C, holding time 30 min, coal ratio = 1, a product with a metallization rate of more than 70% can be obtained, which meets the requirements of the rotary kiln process, and its CO2/CO value of the pre-reduction endpoint is appropriate. Continue to increase the temperature, holding time, and coal ratio can raise the metallization rate of the pellets, but only a little improvement and may cause reoxidation of the product

Study on the Grinding Kinetics and Magnetic Separation of Low-Grade Vanadiferous Titanomagnetite Concentrate

In recent years, a low-grade vanadiferous titanomagnetite concentrate (LVTC) produced in the northwest area of Liaoning has attracted more and more attention. However, it is difficult to recover and utilize valuable minerals such as iron, titanium, and vanadium, due to their special physical and chemical properties and complex mineral composition. Grinding and magnetic separation are two important operational units for recovering valuable metal components from vanadiferous titanomagnetite. Therefore, the grinding kinetics of the LVTC in northwestern Liaoning were first studied by means of grinding kinetics equations in this paper. The results show that the grinding process of LVTC is consistent with the grinding kinetics equation, and the sieve residues of particles approached a constant value after grinding for 30 min, resulting from equilibrium between the fragmentation and agglomeration processes. In addition, equivalent particle size (EPS) and specific surface area (SSA) were linearly proportional to the double logarithm of grinding time, and the correlation coefficients for fitted data by the Rosin–Rammler–Bennet (RRB) model were slightly higher than those by the Swebrec model, and could reflect the dispersibility and uniformity of particle size distribution (PSD) quantitatively. Then, the grinding products were separated by magnetic separation, and the influence of grinding conditions on the grade and recovery ratio of Fe and TiO2 in the LVTC was analyzed. As a result, grinding time has a significant impact on the recovery ratio and grade of Fe and TiO2 during the magnetic separation process, and the LVTC grinding duration is not as prolonged as it might be, as the optimal grinding time is 20 min. Titanomagnetite, ilmenite, and titanite are still the predominant phases in all magnetic separation products at optimal grinding time, but the intensity or content of these three minerals varies between magnetic separation products, and 232 kA/m magnetic field intensity has a higher separation efficiency than 134 kA/m magnetic field intensity

Recovery of Iron, Chromium, and Nickel from Pickling Sludge Using Smelting Reduction

This paper reports the recoveries of iron, chromium, and nickel from pickling sludge using coal-based smelting reduction. The influences of slag basicity (CaO/SiO2, which is controlled by high phosphorus oolitic hematite iron ores), reduction temperature, reduction time, and the C/O mole ratio on the recoveries of Fe, Cr, and Ni are investigated systematically. The experimental results show that high recoveries of Fe (98.91%), Cr (98.46%), and Ni (99.44%) are produced from pickling sludge with optimized parameters for the smelting reduction process. The optimized parameters are a slag basicity of 1.5; a reduction temperature of 1550 °C, a reduction time of 90 min, and a C/O mole ratio of 2.0. These parameters can be used as technical support for the recycling of pickling sludge with pyrometallurgy