<span style="font-family:Verdana;">The article provides a theoretical analysis of the velocity distribution and distribution in the cross section of the pipe during the transportation of cotton. It stu...<span style="font-family:Verdana;">The article provides a theoretical analysis of the velocity distribution and distribution in the cross section of the pipe during the transportation of cotton. It studied the factors that move air and transport material in a </span><span style="font-family:Verdana;">pneumatic pipeline, developed a mathematical model and built graphs. The effect of pressure on the ease of construction of pipes for air transportation of raw cotton and the speed distribution in the process of transporting cotton, as well as the factors that cause pressure loss in the shells of pipes were studied.</span><span style="font-family:""> </span><span style="font-family:Verdana;">So, i</span><span style="font-family:Verdana;">f the expansion after the air </span><span style="font-family:Verdana;">pipe</span><span style="font-family:""><span style="font-family:Verdana;"> is expanded </span><img src="Edit_111b42e7-ead7-4f9b-8a57-0a3b41fff1a6.png" alt="" /></span><span style="font-family:""></span><span style="font-family:Verdana;"> (5), we will</span><span style="font-family:""><span style="font-family:Verdana;"> introduce </span><i><span style="font-family:Verdana;">K</span></i><sub><span style="font-family:Verdana;">1</span></sub><span style="font-family:Verdana;"> = 0 and the beating coefficient </span></span><span style="font-family:""></span><span style="font-family:Verdana;">. If the current narrows before</span><span style="font-family:""><span style="font-family:Verdana;"> burdening, then we enter </span><i><span style="font-family:Verdana;">K</span></i><sub><span style="font-family:Verdana;">1</span></sub><span style="font-family:Verdana;"> = 1 and the input </span></span><span style="font-family:Verdana;">soften</span><span style="font-family:Verdana;"> rate from the formula </span><span style="font-family:""></span><span style="font-family:Verdana;">.</span><span style="font-family:Verdana;"> The air flow is moving upwards below the slope and the longer the pipe is the air flow is so significant 展开更多
Current work is focused on the influence of friction in deep drawing process. Friction measurements were also conducted using a modified tribotester based on strip sliding between tools. Four different tool surfaces w...Current work is focused on the influence of friction in deep drawing process. Friction measurements were also conducted using a modified tribotester based on strip sliding between tools. Four different tool surfaces were tested under similar contact conditions regarding contact area, normal pressure, sliding speed, lubricant and surface characteristics to calculate the friction coefficient between the tool surface and a high strength low alloy steel sheet HSLA 380. The results showed that friction coefficient varies over a wide range with different lubricating conditions and different sliding velocities. For some sliding velocities, the coefficient of friction is stable and low, while for others it is unstable and higher. Results of the experiments reveal that this novel tribotester is a very useful tool to evaluate and compare the friction between steel sheet and tool surfaces in alloyed steel for cold working applications. The outcomes have only small dispersion within the different test series, which indicates a stable process with good repeatability. The test method enables comparison of different surface finishes and treatments, lubricants and coatings in terms of friction and galling under conditions similar to those found in sheet metal forming processes. The four different types of surfaces considered for this study were grinded, polished, nitrided and quenched/tempered. The main difference among the tested tools in this work was the surface roughness, which was found to have a strong influence on friction.展开更多
In the paper the simplified criterion of a steady-state stability of electric power systems (EPS) is justified on the basis of Lyapunov functions in a quadratic form ensuring necessary and sufficient conditions of its...In the paper the simplified criterion of a steady-state stability of electric power systems (EPS) is justified on the basis of Lyapunov functions in a quadratic form ensuring necessary and sufficient conditions of its performance. Upon that, the use of the node-voltage equations allows reducing study of a steady-state stability of complex EPS to study of the generator-bus system. The obtained results facilitate studies of a steady-state stability of the complex systems and have practical importance.展开更多
The advisability of the use of matrix methods of equations rearrangement for the investigated system which allows writing a secular equation is considered in this article. This approach greatly simplifies the analysis...The advisability of the use of matrix methods of equations rearrangement for the investigated system which allows writing a secular equation is considered in this article. This approach greatly simplifies the analysis of performance of transient response in complicated multi-coupled electrical system at small perturbations.展开更多
文摘<span style="font-family:Verdana;">The article provides a theoretical analysis of the velocity distribution and distribution in the cross section of the pipe during the transportation of cotton. It studied the factors that move air and transport material in a </span><span style="font-family:Verdana;">pneumatic pipeline, developed a mathematical model and built graphs. The effect of pressure on the ease of construction of pipes for air transportation of raw cotton and the speed distribution in the process of transporting cotton, as well as the factors that cause pressure loss in the shells of pipes were studied.</span><span style="font-family:""> </span><span style="font-family:Verdana;">So, i</span><span style="font-family:Verdana;">f the expansion after the air </span><span style="font-family:Verdana;">pipe</span><span style="font-family:""><span style="font-family:Verdana;"> is expanded </span><img src="Edit_111b42e7-ead7-4f9b-8a57-0a3b41fff1a6.png" alt="" /></span><span style="font-family:""></span><span style="font-family:Verdana;"> (5), we will</span><span style="font-family:""><span style="font-family:Verdana;"> introduce </span><i><span style="font-family:Verdana;">K</span></i><sub><span style="font-family:Verdana;">1</span></sub><span style="font-family:Verdana;"> = 0 and the beating coefficient </span></span><span style="font-family:""></span><span style="font-family:Verdana;">. If the current narrows before</span><span style="font-family:""><span style="font-family:Verdana;"> burdening, then we enter </span><i><span style="font-family:Verdana;">K</span></i><sub><span style="font-family:Verdana;">1</span></sub><span style="font-family:Verdana;"> = 1 and the input </span></span><span style="font-family:Verdana;">soften</span><span style="font-family:Verdana;"> rate from the formula </span><span style="font-family:""></span><span style="font-family:Verdana;">.</span><span style="font-family:Verdana;"> The air flow is moving upwards below the slope and the longer the pipe is the air flow is so significant
文摘Current work is focused on the influence of friction in deep drawing process. Friction measurements were also conducted using a modified tribotester based on strip sliding between tools. Four different tool surfaces were tested under similar contact conditions regarding contact area, normal pressure, sliding speed, lubricant and surface characteristics to calculate the friction coefficient between the tool surface and a high strength low alloy steel sheet HSLA 380. The results showed that friction coefficient varies over a wide range with different lubricating conditions and different sliding velocities. For some sliding velocities, the coefficient of friction is stable and low, while for others it is unstable and higher. Results of the experiments reveal that this novel tribotester is a very useful tool to evaluate and compare the friction between steel sheet and tool surfaces in alloyed steel for cold working applications. The outcomes have only small dispersion within the different test series, which indicates a stable process with good repeatability. The test method enables comparison of different surface finishes and treatments, lubricants and coatings in terms of friction and galling under conditions similar to those found in sheet metal forming processes. The four different types of surfaces considered for this study were grinded, polished, nitrided and quenched/tempered. The main difference among the tested tools in this work was the surface roughness, which was found to have a strong influence on friction.
文摘In the paper the simplified criterion of a steady-state stability of electric power systems (EPS) is justified on the basis of Lyapunov functions in a quadratic form ensuring necessary and sufficient conditions of its performance. Upon that, the use of the node-voltage equations allows reducing study of a steady-state stability of complex EPS to study of the generator-bus system. The obtained results facilitate studies of a steady-state stability of the complex systems and have practical importance.
文摘The advisability of the use of matrix methods of equations rearrangement for the investigated system which allows writing a secular equation is considered in this article. This approach greatly simplifies the analysis of performance of transient response in complicated multi-coupled electrical system at small perturbations.
