On IEC 61850 communication networks in smart grids system: Methodology of implementation and performances analysis on an experimental platform

The increasing installation of distributed energy resources during the last years has led to a fundamental change in the power system structure. As a consequence, utility operators are faced with new challenges in grid planning and control. The consideration of smart grids show promising results in increasing the hosting capacity for distributed and renewable resources. Standardized automation, control, and communication systems are important keys to realize such intelligent methods. This paper focuses on a deployment methodology of IEC 61850 on an experimental platform for smart grid system. We were interested in evaluating the performance of the GOOSE communication. A standard-based communication approach for distributed energy resources is introduced and implemented. It uses the IEC 61850 interoperability approach as well as the GOOSE communication for distributed automation. The implementation methodology is provided to handle the hierarchical architecture of distributed control applications. In order to show the advantages of the proposed methodology, a combined analytical and experimental approach is demonstrated for evaluation of GOOSE communication performances.     

Metal Dusting Protective Coatings. A Literature Review

Metal dusting is a catastrophic form of carburization attack that takes place in carbon-supersaturated gaseous atmospheres, and is most commonly encountered in steam reforming processes such as the production of hydrogen or syngas for ammonia, Fischer?CTropsch and methanol applications. The consequence of metal dusting can be a severe loss of metal from the process units, leading to high-cost maintenance and serious safety issues. The present literature review discusses the latest developments within metal dusting protection of alloys with special emphasis on protective coatings. In the first part of the paper, an overview of the main theories for metal dusting of alloys as well as fundamental studies is provided. In the second part, the paper focuses on the different methods to prevent metal dusting, including surface poisoning, alloying, chemical, mechanical and laser treatments as well as coatings. Particular focus is given to coatings and their composition, and fabrication methods, and a critical analysis of the different materials?? behaviours and the suitability perspectives of deposition techniques are provided.     

Multifunctional ultralight,recoverable, piezoresistive,and super thermal insulating SiC nanowire sponges

Ultralight three-dimensional (3D) architectured silicon carbide (SiC) nanowire sponges with integrated properties of recoverable compressibility, outstanding high-temperature thermal and chemical stability, and fire-retardance have been actively pursued in recent years. However, efficient construction of SiC nanowire sponges with well-controlled overall shapes and distribution of SiC nanowires remains challenging. Herein, by coupling the electrospinning technique and carbothermal reduction process, we have developed a new fabrication process for highly porous and free-standing 3D SiC nanowire (SiCNW) sponges with closely attached nanowires through thermal treatment of stacked electrospun PAN/SiO₂ nanofiber membranes. The resulting SiCNW sponges possess ultralow density (∼29 mg cm⁻³), excellent compressive recoverability from large compressive deformation (up to 40% strain), and fatigue resistance, which endow them with excellent piezoresistive sensing capability under a variety of complex conditions. Furthermore, the sponges display superb thermal insulation (thermal conductivity of 24 mW m⁻¹K⁻¹) and fire-retardance. We believe that the present process provides technical clues for the development of other multifunctional ceramic sponges, and that further development of these ultralight multifunctional ceramic sponges offers potential for the design of advanced components for application in harsh engineering environments.     

Study of turbulent natural convection coupled with thermal radiation in a vertical cavity having a large form factor

In this study, a numerical simulation study of turbulent natural convection coupled with thermal radiation in a vertical cavity differentially heated and filled with air assumed as a transparent fluid was carried out. The cavity has a variable form factor which can reach large values. The vertical walls are subjected to constant temperatures (T_c and T_f), whereas the horizontal walls are assumed adiabatic. The flow inside the cavity is turbulent and turbulence was modeled by using the $K?\epsilon$ model, and to take into account of the radiative transfer, the discrete ordinate model (DO) was introduced. To solve the different equations, Ansys‐Fluent software based on the finite volume method was used. Some numerical results obtained for the Rayleigh number value of 10¹¹ have been validated by some existing results in the theory. It is found that the thermal radiation has a significant influence on the flow structure and temperature variation where the flow becomes reinforced. It accelerates the airflow inside the cavity and gives the formation of significant velocity and temperature gradients along the walls of the cavity. Taking into account of the surface, thermal radiation is essential in the correct evaluation of temperature in the cavity.     

Numerical Analysis of Thermal and Dynamic Behavior of a Roof Solar Collector

In some regions with a specific climate, summer comfort in the rooms located below the roof becomes critical if the roof system is not well designed. In order to analyze the efficiency of this system a numerical model was developed. This model is based on the study of the natural convection coupled with radiative heat transfer in an inclined air channel. The configuration studied is an inclined channel formed by two parallel plates. The upper and lower plates were maintained at fixed temperatures. The air flow in the channel which is due to the buoyancy forces is fully turbulent and the turbulence was modeled by using the k‐ε model. Some numerical results obtained were validated using the experimental works of Khedari and colleagues and those of Nouanégué and colleagues. The effect of physical and geometrical parameters and the radiative heat transfer on the channel behavior is shown. Correlations for Nusselt numbers and air flow rate were obtained as functions of the geometric parameters and the Rayleigh number. These correlations can be used in other models that represent this system.     

Quality of water in hemodialysis centers in Baghdad,Iraq

Dialysis water quality is one of the important parameters all over the world because of its direct influence on the health of kidney patients. In Iraq, there are more than 20 dialysis centers; most of them contain identical units for the production of dialysis water. In this work, the quality of water used for dialysis in six dialysis centers located within Baghdad hospitals was evaluated. Samples of product water from each of the six dialysis centers were examined for total heterotrophic bacteria, endotoxin, and chemical contaminants. Endotoxin was measured on‐site using a portable instrument. Bacteriological and chemical examinations were done in the laboratory after collecting samples from each dialysis center. The results showed a fluctuation in the produced water quality that makes the produced water unaccepted when compared with international standards. Bacterial counts for 60% of the analyzed samples were above the action level (50 colony‐forming units[CFU]/mL), while five out of the six dialysis centers showed values higher than the maximum value (100 CFU/mL). Chemical analysis showed that the dialysis water quality suffers from elevated aluminum concentration for all dialysis centers. All hemodialysis centers need thorough monitoring and preventive maintenance to ensure good water quality. In addition, it is important to revise the design of the water treatment units according to the feed and product water quality.     

Effect of heat and transglutaminase on solubility of goat milk protein‐based films

The effect of heat, transglutaminase and combination of heat and transglutaminase treatments on the solubility of films prepared from goat milk casein, goat milk whey proteins and whole goat milk proteins was investigated. Goat milk casein films were less soluble when treated with transglutaminase and combination of heat with transglutaminase compare with heat‐treated caseins alone. Heat treatment was more effective at decreasing the solubility of whey protein films. SDS‐PAGE patterns demonstrated that goat milk caseins were better cross‐linked by transglutaminase, whereas whey proteins were better cross‐linked by heat. The extent of cross‐linking was further enhanced when a combination of heat and transglutaminase was used.     

Experimental investigation of the processes of complex loading of alloy AMg6

The article presents the results of tests with tubular specimens of aluminum alloy AMg6 subjected to simultaneous tension and internal pressure on a load trajectory in the form of two-link broken lines with the break angle of 90° in the stress space. It is shown that the experimental results agree well with those obtained according to the theory of quasisimple processes.Translated from Problemy Prochnosti, No. 5, pp. 36–42, May, 1993.