Research on the key parameters of tube mold for rail steel bloom was carried out in this paper, the effects of cooling water on bloom quality was studied, the effects of tube mold on magnetic intensity of electro-magnetic-stirring was analyzed, the shielding effect of tube mold on stirring intensity was represented by comparing solidification structure, suitable stirring parameters was confirmed; the effects of tubular corner size on cooling of bloom corner was analyzed by taken simulate calculate, and explore the effects of taper on the casting amount of steel by carried out experiment, parameters have been worked out and quality of bloom corner have been improved at last, convex hull of corner have been eliminated and zero defect for corner was realized, mean squared error of segregation degree at corner and solidified shell is not more than 0.010, better than combined mold remarkably.
Fractional-order Fourier transform is a representational method of the fractional Fourier domain formed by the signal rotated by any angle counterclockwise about the origin on the coordinate axis in the time-frequency plane. This paper intends to use the Fractional-order Fourier transform to process the signals collected from the acoustic emission device, and then train the results through the ensemble method of SVME, KNN and Softmax, so as to build a model that can predict size and location of leak holes in acoustic emission device. The model process has a good accuracy in predicting that whether or not the leak and the size of the leak are empty. If you only need to predict whether it leaks, the accuracy reaches 75.6 %, compared to the model trained on the original data, the classification accuracy has increased by 25.6% to 66.8%. In particular, on the Softmax classifier, the addition of FFRT increases the accuracy by more than 200%.
High nickel ternary cathode materials are less expensive, more productive, and less environmentally harmful than conventional cathode materials. Thus, it becomes one of the best cathode materials for lithium-ion batteries. However, there are also clear drawbacks to high nickel ternary materials, for instance its inadequate cycle life, poor structural and heat stability, which limit its future development. In this work, LiNi0.8Co0.1Mn0.1O2 (NCM811) material was studied and modified using Li3BO3, a lithium-ion conductor-type compound, as its coating layer. Studies reveal that after 1 wt percent -Li3BO3 coating, the first discharge capacity at a 2 C rate rose from 162.7 mAh g-1 to 185.9 mAh g-1. After 250 cycles, the capacity retention of the Li3BO3-coated sample was 87%, compared to just 82.5% for the uncoated sample. The introducing of Li3BO3 coating material of NCM811 can significantly improve the electrochemical performance of materials for lithium-ion battery cathodes that are high in nickel ternary.
The design of marine gas turbine exhaust system is related to the normal operation of gas turbine and even the overall performance indexes of the ship. In this paper, the influence of exhaust system on the gas turbine, the infrared stealth performance of the whole ship and ship surface equipment is specifically analyzed. In view of these influences, the main points of design of marine gas turbine exhaust system are presented in this paper, which can provide reference for the design of gas turbine exhaust system. The Design points includes: (1) the exhaust system resistance, (2) the cooling air injection effect of the exhaust system case body, (3) improving the infrared stealth performance of the exhaust system, (4) smoke outlet position of exhaust system.
Mechanization level in terms of usage of farm machinery and farm power in 22 Upazillas and 2 Unions of 13 districts were ascertained. Farm level recent data on machinery and power usage had been collected through questionnaire survey in addition to the previous data from secondary sources. The trend of population of most of the farm machinery continues to rise which got a boost up since late 80s with an increasing demand. Population of tractor, PT, open and close drum thresher, and irrigation pumps has been increased tremendously since then. Population of tractor, PT, seeder, combine harvester, and reaper almost doubled in 2014 over that in 2011. Other machineries such as high-speed rotary tiller, weeder, seeder, sprayer, maize sheller, winnower, USG applicator also got a hike (12% - 50%) in population during this period. Farm machinery like reaper, combine harvester, winnower, USG applicator, and seeder had been observed to be introduced during the recent years. Availability of farm power varied widely among the Upazillas under study and Upazilla wise average value of farm power usage was found to be 1.21 kW/ha. Considering accumulated cultivated area and power usage of all the selected areas, the present study showed that available power further escalated to 1.23 kW/ha by 2014 with an increasing annual average rate of 0.052 kW/ha/yr since 1998 followed by a slower rate (0.021 kW/ha/yr) since 2007. The share of mechanical power was found to be prominent over human and animal power in almost all the study areas followed by animal and human power sources. A major portion, about 60 – 97% of the total farm power used in the study area was supplied by the mechanical source.
AbstractThe pulsed vacuum arc discharge is an effective technology for the deposition of ta‐C coatings on tools and machinery parts. The properties of these carbon coatings differ substantially from conventional hard nitride films particularly with regard to hardness and wear‐resistance. The paper shows analytical results of ta‐C films in comparison to such hard coatings. Thereby different methods are applied for determination of adhesion, friction, wear‐resistance, and indentation hardness. A simple correlation was found between indentation hardness and wear‐resistance over a wide range of hard materials. Furthermore, all investigated films have a strong adhesion on steel in conventional Rockwell tests. But in scratch tests with increasing normal forces brittle ta‐C films delaminate at lower forces from the surface compared to nitride coatings.
Rafael Åman, Heikki Handroos, Hannu Kärkkäinen
et al.
The improvement of the energy efficiency is an important topic for non-road mobile machinery developers and manufacturers. These machines normally use fluid power transmission in drivelines and working actuators. New energy efficient technologies, e.g. a hybrid power transmission with an energy recovery feature, have been introduced. Currently most of the manufacturers are still using conventional technologies in their product development process. Human operators have an effect on the overall efficiency of the machines. Taking into account the human effects is difficult and expensive using the conventional design processes and tools. The objective of this study is to provide international machine manufacturers instrumental, yet novel, community and simulation-based (ICT-enabled) tools/methods for the strategic and cost effective development of their product practices and design processes. The development of models and methods will allow for rapid real-time virtual prototyping of complex machines and machine fleets that operate within a number of worksites or geographical conditions. The introduction of this state-of-the art (and going beyond) advancement in real-time virtual technology, simulation, internet based design technologies and software, cyber-physical and big data processing systems, will present a holistic approach to improve the entire product life. Targeted user groups are manufacturers of non-road mobile machinery (i.e. excavators, wheel loaders, etc.). These machines and production systems share the following key features: 1) They are complex mechatronic systems with several interconnections between hydraulic drives; mechanics, electronics, software and 2) they include autonomous, semiautonomous and human driven operated systems. Methods developed will enable machine manufacturers’ access to technologies that will lead to a more cost effective consumer ordinated, life cycle optimization process. This paper will introduce the method of developing customized products in a fast, agile and networked way that will lead to significantly reduced life-cycle costs.
Department of Farm Machinery, Agricultural Engineering College and Research Institute Tamil Nadu Agricultural University, Coimbatore - 641 003, Dhananchezhiyan P, Parveen S
et al.
A portable power paddy thresher was developed for small farmers. A cross flow portable power paddy thresher cum winnower was fabricated based on cylinder- concave mechanism and its performance was assessed in terms of threshing efficiency, grain damage and output capacity and compared with conventional methods of threshing. The portable paddy thresher was field tested and its threshing efficiency, damaged grains and output of the thresher were found to be 99.85 %, 2.85 % and 235.65 kg h-1, respectively. The saving in cost and time of the portable power paddy thresher were 86.5 % and 95 %, respectively as compared to manual threshing. The break-even point for the developed portable power paddy thresher was 205 hours of use per year.