Multi-level cross-layer protocol for end-to-end delay provisioning in wireless multimedia sensor networks

Frontiers of Information Technology & Electronic Engineering - Rapid developments in information and communication technology in recent years have posed a significant challenge in wireless...     

Distributed data-driven observer for linear time invariant systems

This paper is concerned with distributed data-driven observer design problem. The existing data-driven observers rely on a common assumption that all the information about the system, and the calculations based upon this information are centralized. Therefore the resulting algorithms cannot be applied to the distributed systems in which each local observer receives only a part of the output signal. On the other hand, traditional model-based distributed state estimation methods generally assume that the processes are decomposed according to the known process models, while in data-driven approaches there is no such information available. The main goal of this paper is to extend the centralized data-driven observer design approach to the distributed framework. The stability of the proposed data-driven distributed observer is also proved analytically. A quadruple-tank process is simulated to demonstrate the performance of the proposed scheme.     

Estimation of the activation of local reactor shielding concretes

Many elements in reactor shielding concrete become radioactive due to interaction with neutrons during the operation of a nuclear reactor. These radioactive elements will build up over the time due to (n,γ) reaction and contribute to the radioactive waste during decommissioning of the reactor, they will increase the dose from the inner part of the biological shielding (concrete) surrounding a nuclear reactor during maintenance works within reactor containment, and their effect should be taken in the calculations of the dose behind the concrete shield.Six mixtures of local ordinary and special shielding concretes have been investigated in this study. Their compositions were determined using X-ray diffraction and neutron activation analysis using the Syrian Miniature Neutron Source Reactor (MNSR) and consequently the dose rates.Based on the results of the analyses and comparing to the published limits in the references, it has been found that ⁶⁰Co, ¹⁵²Eu, ¹⁵⁴Eu and ¹³⁴Cs will be the most effective radioactive nuclides existing in the local concrete, but Dolomite aggregates contain the minimum limits of them and it has been found that Fe, Mg, and Ti the major elements existing in the local concrete.     

Lumped Parameter Thermal Model for Axial Flux Switched Reluctance Motors

The accurate prediction of temperature rise in various parts of a machine plays a significant role in ensuring that the machine delivers the required performance avoiding failures that arise due to high temperatures. In this paper, a lumped parameter thermal model is presented for exterior-rotor axial flux switched reluctance motors. Depending on its geometry, each part of the motor is modeled as a thermal equivalent circuit based on general cylindrical or cuboidal components. A total thermal network is obtained by proper connection of these sub-circuits. The model was calibrated by a stationary test; then, running conditions were applied to the model. The sensitivity of the model to the heat transfer coefficients was investigated by considering the effect of the coefficient variation on the estimated steady-state temperatures. Results show that the winding temperature, as the hottest part of the motor, is the most sensitive to the frame-to-ambient heat transfer coefficients.     

Large particle effects in chemical/biochemical heap leach processes - A review

The application of heap leach technology to recovery of economically important metals, notably copper, gold, silver, and uranium, is wide-spread in the mining industry. Unique to heap leaching is the relatively coarse particle size, typically 12-25 mm top size for crushed and agglomerated ores and larger for run-of-mine dump leaching operations. Leaching from such large particles is commonly assumed to follow shrinking core type behaviour, although little evidence for the validity of this assumption exists. This review investigates the current state of knowledge with respect to the understanding of the characteristics and mineralogy of large particles and how these influence leaching in a heap context and the tools to characterize these. This includes the study of ore and particle properties, visualization techniques for ore characterization, the connection between comminution and leaching behaviour, as well as particle models within heap leach modelling. We contend that the economics of heap leaching are strongly governed by the trade-off between the slow rate and limited extent of leaching from large particles and the cost of crushing finer. A sound understanding of the underlying large particle effects will therefore greatly inform future technology choices in the area of heap leaching.     

Making concrete with saline well-water

Permitted limits of salt concentrations in water used for making mortar and plain concrete differ from one country to another, but in any event geographical conditions prevent this guidance being applied directly to Saudi Arabia. Comparing the effects on compressive strength of saline well-water and drinking quality water, scientists at the Department of Building Research in the Saudi Arabian Standards Organisation show in this article that well-water with total dissolved salts (TDS) concentrations up to 4500 ppm can be suitable for mixing and curing mortars and plain concrete.