Papers by Keyword: Coverage

Abstract: The article considers methods of manufacturing non-toxic films of a given color that meet technological requirements. The problem of reducing the shrinkage of the colored polymer in the casting mould during cooling and maintaining its technical characteristics is experimentally solved. To this end, the influence of the nature of pigments on the degree of polymer coloring is studied, and ways to improve the quality of color are investigated. The object of the study was selected pigment concentrate based on high pressure polyethylene brand 15803-003. The pigment has chosen technical carbon grades N220, P803. Surfactants were modifying additives. Tests of samples to determine the light fastness of dye, migration resistance, the number of agglomerates of pigments, toughness and strength, physical and mechanical properties showed that the most effective additive to improve the coloring properties of soot pigment brand N220 and improve the appearance of finished products introduced into the superconcentrate calcium stearate, which at the stage of mixing in the extruder acts as a surfactant and prevents the adhesion of the pigment and the formation of agglomerates in the polymer melt.

Abstract: Shot peening is one of the most powerful mechanical peening techniques applied in surface engineering to improve the mechanical properties of metal alloys by introducing compressive residual stresses. During shot peening process, surface integrity, such as microstructures, surface roughness, hardness and residual stress can be varied by adjusting the operating parameters of shot peening. To facilitate the understanding of the microstructure and properties variation, in our latest work, shot peening with high coverage percentage has been employed to create severe plastic deformation on stainless steel 304 (SUS304). Morphological and topological study on the shot peened coupons were carried out using microscopes and 3D optical profiler. Residual stress depth profiling was evaluated using X-ray diffraction technique. Microstructures, phase distribution and crystal orientation were analyzed by electron backscatter diffraction technique. The results show that phase transition γ - α’ and grain refinement occur during this mechanical peening process. A nanocrystalline layer with preferred orientation formed near the surface, and dislocations accumulated within sub-surface area, which can be attributed to the high energy input from the peening process. The maximum compressive residual stress, which is around 1000-1200 MPa, occurred beneath the top surface. All these findings will provide guideline for surface engineering at various scales and designing of the surface enhancement process via mechanical peening for achieving optimum surface integrity of metallic alloys.

Abstract: Copper nickel (Cu-Ni) coatings on products from instrumental steel H12M were drawn and they were subjected to subsequent intensive plastic deformation under stresses 3.0; 3.5; 4.0 and 4.5 GPa. The nanostructured surface, formation grains size of 13...173 nm with high-angle (at 3.0; 4.0; 4.5 GPa) and low-angle (dislocation) borders of grains (at 3.5 GPa), influencing redistribution of alloying elements and tribological properties was shown by means of methods of light and electronic microscopy, X-ray diffraction and micro-ray spectral analysis, and also tribological tests.

Abstract: The relations between shot peening coverage and fatigue strength in the quenched-tempered and annealed medium-carbon steels and aluminum alloy A7075-T6 were experimentally studied using a rotating bending fatigue testing machine. It was found that the fatigue strengths of the annealed steel and aluminum alloy were increased by shot peening. On the other hand, the fatigue strength of the quenched-tempered steel were not increased by shot peening. Same shot peening condition causes the positive effect and the negative effect depending on the type of material. Moreover, the valuable coverage might depend on the type of material. More detailed work is necessary to resolve the issue.

Abstract: In order to improve the detection performance with the limited radar resources in the given defense zone, it is necessary to make reasonable and effective deployment of radar network. According to the principles of radar network deployment, its mathematical model is established at the beginning. And then, on the base of the shuffled frog leaping algorithm (SFLA) principle, a new method-improved shuffled frog leaping algorithm (ISFLA) is introduced through the technique of algorithm hybrid. By integrating updated strategy and chaotic optimization into SFLA, it greatly enhances the local searching efficiency and global searching performance. Moreover, the frogs are divided into two types and perform different operations to co-evolve. Finally, by analyzing an example and comparing the results with those algorithms, it comes to a conclusion that several network schemes can be obtained much more quickly by this way with better operability.

Abstract: One of the major challenges in constructing wireless sensor networks (WSNs) is to ensure the quality of coverage (QoC) as well as save energy. Considering the cooperative sensing model and the random deployment policy, the judgment model of redundant node without location information is presented. Furthermore, the distributed collaborative scheduling algorithm (DCSA) is designed to guarantee the QoC of networks with the least number of nodes. It chooses the uniformly-located working nodes and makes sure that the energy consumption of each node consumes homogeneously. Simulation results show that the DCSA policy not only provides the desired QoC of networks, but also reduces the number of working nodes significantly, saves the energy of the networks, and extends the network lifetime.

Abstract: In sensor networks, a reasonable distribution of sensor nodes is an important role for the improvement of sensor ability, information collection ability and network survival. For multilayer mobile sensor network, a tree-based deployment optimization scheme was proposed and better sensor coverage could be achieved by topology adjustment utilizing mobility of sensor node. Sink nodes complete mobile positioning of S nodes based on rectangle division method and bounding box algorithm, and achieve the distribution optimization of S nodes by establishing extending-tree of Sink node as the center. Results show that the location error ratio reduces with the increase of Sink nodes. Compared with initial random deployment network, the network coverage ratio after optimal deployment significantly enhances, which effectively improve the coverage sensor range of overall network.

Abstract: Influence of possible fluctuations of a chemical composition of waste of galvanic productions on the mixed iron oxide pigment (MIP) main pigmentary properties is established. It is shown that introduction of samples of MIP with the raised content of these or those metals in such industrial paintwork materials as alkyd PF-115 enamel and a primer GF-021, practically doesn't change physic-mechanical properties and firmness of the coverings received on their basis. It allows to apply slimes of galvanic productions as the main raw materials by industrial production of MIP and to reduce prime cost of a pigment by 15-20%.

Abstract: The substance of the deployment of radar network is a multi-parameter optimization problem. This paper presents an objective function to deploy the radar network and a shuffled frog leaping algorithm (SFLA) is proposed to implement the radar network deployment. The proposed cultural shuffled frog leaping algorithm (CSFLA) makes use of mechanism of cultural evolution to update the locations of cultural frogs. Simulation results show that the proposed CSFLA has stronger abilities of exploitation and exploration by designing new leaping equations based on knowledge strategy and information communication, which may obviously improve the performance of SFLA. The radar network deployment based on the CSFLA is superior to previous deployment based on particle swarm optimization (PSO) and the SFLA in the convergence speed and optimization results. It provides a new idea to the radar network deployment.

Abstract: In order to achieve the optimal detection performance with the limited radar resources in the given defense area, the reasonable and effective deployment of radar netting is needed. According to the degree of importance of the detection region and the setting of the appropriate weighting coefficients of each of coverage, a mathematical model is established at the beginning. And then, on the base ofthe shuffled frog leaping algorithm (SFLA) principle, the solving process ofthe SFLA for this optimization problem is discussed in detail and the SFLA to expedite the solving velocity is presented. Finally, by analyzing an example and comparing the resultswith that of the ant colony algorithm (ACA), it comes to a conclusion that several network schemes can be obtained much more quickly in this way with better operability.