Spinning process optimization and microstructure of stainless-steel welded pipe

Defects, such as cracks, typically occur in the spinning process of ternary catalyst shells. This study investigates the optimization of spinning process parameters to prevent such defects. An orthogonal simulation is performed using a finite element model of the spinning process of a ternary catalyst shell. The simulation results are verified by performing spinning tests using a 439 stainless steel welded pipe. The microstructure, hardness, and quality of formed parts are analyzed. The simulation and test results demonstrate that when the spinning temperature is 1000 °C, the roller fillet radius, roller speed, and feed ratio are 5 mm, 40 r/s, and 1.2 mm/r, respectively. In addition, the error rates of the forming thickness, port diameter, and roundness error are 1.37%, 1.25%, and 4.8%, respectively. This verifies the accuracy of the simulation. No defects are generated during spinning, and the spinning quality is high. The feed ratio is the main factor that affects the roundness error, followed by the roller speed. As deformation increases, hardness increases and the crystal size decreases. The results of this study can provide important theoretical guidance for practical spinning applications.

Simulation of a maize ear picking device with a longitudinal horizontal roller based on hypermesh modeling

As a key component of mechanized maize harvesting, the performance of the ear picking device directly affects the operational level of a maize harvester. Because the short harvest period of maize and the multiple experimental factors that lead to the field and bench tests cannot meet the actual research and developmental needs of manufacturing a maize harvester, this paper uses virtual prototype technology to study the influence of design and the motion parameters of a longitudinal horizontal roller in terms of picking performance. Based on the establishment of the finite element model of the corn and the ear picking device, this paper establishes evaluation indicators respectively, analyzes and evaluates the influence of the picking roller and the ground inclination angle, the picking roller speed, and the forward speed of the harvester on the performance of ear picking. Finally, a virtual orthogonal test analysis was carried out for the two factors of the picking roller speed and the forward speed of the harvester, and the significant influence of the picking roller speed and the forward speed of the harvester on the performance of the picking was compared. The research results of this paper can provide reference for optimizing the design of ear picking mechanism.

An Adaptive Roller Speed Control Method Based on Monitoring Value of Real-Time Seed Flow Rate for Flute-Roller Type Seed-Metering Device

In order to obtain desirable crop yields, grain seeds need to be sown at the optimal seed amount per hectare with uniform distribution in the field. In previous grain sowing processes, the seeding rates are controlled by the rotational speed of the flute roller which significantly effects the uniform distribution of the seeds due to disturbances, such as the reduction of the seeds’ mass in the hopper and the change of working length of the flute roller. In order to overcome the above problem, we developed an adaptive roller speed control system based on the seed flow rate sensor. The developed system can monitor and feedback actual seeding rates. In addition, based on the monitoring value of the real-time seeding rates, an adaptive roller speed control method (ARSCM), which contains an algorithm for calculating the seeding rate with a compensation, was proposed. Besides, the seeding performance of the ARSCM and that of the conventional roller speed control method (CRSCM) were compared. The results of constant-velocity experiments demonstrated that the accuracy (SA) and the coefficient of variation (SCV) of the seeding rates controlled by the ARSCM were 94.12% and 6.77%, respectively. As for the CRSCM, the SA and SCV were 89.00% and 8.95%, respectively. Under variable-velocity conditions, the SA and SCV of the proposed system were 91.58% and 11.08%, respectively, while those of the CRSCM were 88.48% and 13.08%, respectively. Based on the above results, this study concluded that the ARSCM is able to replace the CRSCM in practical sowing processes for the optimal and uniform seed distribution in the field.

Considerations regarding the evolution of roller speed skating in Romania

The fact that in Romania, in the last years, this sport has experienced some regression in terms of number of practitioners is trying to establish whether this affects the achieved results, as the vast majority of the clubs that have speed skating sections still work. Sport selection is of particular importance in achieving the best sports performance, which should be carried out on a continuous basis.This study aims to highlight the evolution of speed skating in our country between 2014-2019, for the senior category, at the national roller speed skating Championship. The events that were targeted in this study are 500m, 1000m, 1500m and 3000m seniors (boys and girls) competitions. The first 3 (or 2, depending on the situation) results per year investigated were collected. The research methods used are: Bibliographic method, data collection and graphical method.From the data shown above it can be noted that, with the exception of the years 2015/2016 (when poor results are most frequently shown) and in two cases during 2018, the achieved results were improved in both girls and boys, in some cases the achieved progress being significant.Although speed skating in Romania is not a sport as publicized as other sports branches, the results are on an ascending line, in the process of improving, which shows that trainers in our country have a level of knowledge comparable to other countries with tradition in the world, increasing funding and attracting sponsorship is one of the factors that can accelerate the advancement of athletes by increasing cantonal numbers, using state-of-the-art equipment, using effort supporters according to their preparation time and age etc.

Effect of Roller Speed and Inclination Angle on the Stem Cutting Efficiency of Shallot Onion

Shallot or aggregatum onion (Allium cepaL. var. aggregation.) is one of the oldest bulb crops known to mankind and extensively grown and consumed in Southern states of India. They are one among the most important commercial vegetable and spice crops, widely used in the south Indian kitchen mainly for seasoning of curries. Aggregatum onion invariably forms afresh cluster of bulbs, often as many as 10 or 15 per cluster. In India, presently about 35 to 40 percent of the onion is estimated to be lost by post-harvest practices during various operations including handling and storage. Presently after harvest onions are processed by hand labor to remove the leaves and the roots. Hand topping has obvious disadvantages including both cost and length of time necessary to process a large number of onions. However, in recent times it is becoming increasingly difficult to find sufficient skilled labor to do the job. Farmers and processors need a suitable post-harvest machine for stem cutting of shallot onion. Owing to the practical problem in the processing of shallot onion a stem cutting machine for shallot onion was designed and fabricated. The fabricated machine with different parameters like the slope of the machine and different speeds of the rollers were optimized. Different slopes (100, 200, 300) with two roller speeda (500 to 1500 rpm) were studied, results observed showed that at 200 slope and 1000 rpm, the cutting efficiency was very good (100%) with less damage to bulbs (2%).

Microstructure and Properties of Rapidly Solidified Al-Zn-Mg-Cu Alloy

Refining grain plays an important role in improving the mechanical properties of aluminum alloys. However, the conventional casting method with a slow cooling rate can be easy to cause coarseness of the microstructure and serious segregation. In this paper, the rapid solidification of Al-Zn-Mg-Cu alloy was prepared by the single-roller belt method. The alloy strip was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and hardness test to study the microstructure and properties of the rapidly solidified aluminum alloy. The results show that the roller speed was an important parameters affecting the formability of the alloy. When the roller speed was 15 m/s, the aluminum alloy produced a thin bandwidth of 5 mm and a thickness of 150 um. As the rotation speed of the roller increased, the cooling rate of the melt increased, and the microstructure of the rapidly solidified Al-Zn-Mg-Cu aluminum alloy strip improved in grains refinement. Compared with the conventionally cast Al-Zn-Mg-Cu aluminum alloys, the Al-Zn-Mg-Cu aluminum alloys prepared by rapid solidification showed much finer crystal grains, and enhanced solid solubility of alloying elements with less precipitation of second phase and high hardness.

DESIGN AND THRESHING OUTPUTS STUDY OF INTERNAL AND EXTERNAL ROTARY ROLLER BUCKWHEAT THRESHER

In order to study the distribution of buckwheat threshing outputs, on the self-designed internal and external rotary roller buckwheat threshing device test bench, the feeding amount was 0.5 kg/s, the internal roller speed was 380 r/min, and the external roller speed was +50 r/min (same direction as the internal roller), 0 r/min and -50 r/min (reverse direction compared to the internal roller) for threshing test. By analysing the overall condition of the threshing outputs, the content of each component in the threshing outputs, and the axial distribution of the threshing roller, it was found that the receiving box below the rasp bar roller mainly contained grains and chaff, leaves and petals, and the receiving box below the spike tooth roller mainly contained short stalks. Under the three conditions, the proportion of chaff in the threshing outputs was 40-45%, the proportion of leaves and petals was 23-29%, the proportion of grains was 13-19%, the proportion of short stalks was 14-16%. Grains, chaff, leaves and petals were mainly concentrated at the front, and short stalks were mainly distributed at the rear of the threshing roller, providing a theoretical basis for the design of the cleaning system.

A DESIGN AND FABRICATION OF ALOE VERA PEELING AND DICING MACHINE

In this research, aloe vera peeling and dicing system is designed and fabricated with high capacity of 5 ton/hr. The system consists of aloe vera fillet, peeling and dicing mechanism. The system is tested for different speed of the roller and leaf thickness. It is concluded that for getting the maximum gel peeling efficiency 98.56%, the system should be carried out at 75 rpm roller speed for 20-22 mm thickness of aloe vera leaves. The dicing efficiency also exhibits high result with mechanism help changing the flexible aloe vera dice size. Moreover, the system also shows the high stability for reaching capacity of 5 ton/hr while running continuously in ten hours.

An experimental verification on existence of air-drag force influencing yarn tension during rotor spinning

Purpose Most researchers have neglected the effect air-drag force on yarn tension during rotor spinning. This paper aims to study the effect of rotor air-vacuum pressure in conjunction with opening roller speed and yarn linear density on the yarn tension generated during the rotor spinning, which has established their significant influences on both the mean and the peak tension.This is the first of one-of-a-kind experimental study being reported to demonstrate the influence of air-drag force on yarn tension during the rotor spinning under dynamic condition. Design/methodology/approach The dynamic measurements on yarn tension at the exit of the doffing tube were carried out by using an electronic capacitive yarn tension meter during rotor spinning. The derived experimental data were fitted into equations to construct the response equations and to work out the coefficients of multiple correlation between the data and the predicted equation for both the mean and the peak tension. Various surface plots were constructed by using those response surface equations, so as to study the effect of variables on yarn tension generated during the rotor spinning. Findings The study has established that the rotor vacuum is responsible in causing a change in yarn tension, it increases with the decrease in air-vacuum inside the rotor. The involvement of the opening roller speed in altering yarn tension during rotor spinning has been proved. As the opening roller speed changes, so does the air stream surrounding the opening roller speed with consequent alteration of the centrifugal force generated due to the rotation of the rotor. The centrifugal force and, hence, the yarn tension generated in the rotor will be simultaneously affected by both the rotor relative vacuum and the opening roller speed. Research limitations/implications This is a structured experimental study to verify the influence of air-drag force generated during rotor spinning on yarn tension. Very limited theoretical work has been carried out in this direction as reported in the introductory part of the paper. The result of the present study will encourage future researchers to revisit the theory on generation of air-drag force during rotor spinning and work out a new formula. Practical implications Next only to the conventional ring spinning system, the rotor spinning holds the second place in the share of global yarn production. Because of its advantage of lower cost of production and amenability to automation, the rotor spinning has gained acceptance in spun yarn production, particularly for spinning coarse and medium counts of yarns. Currently, it has acquired about 25 per cent share in the world’s spun yarn production. As many of the rotor machine variables significantly affect fibre configurations and, subsequently, the yarn properties by influencing the airflow characteristics inside the rotor unit, the study of yarn tension during rotor spinning and its analysis assumes a significance. Social implications Rotor spinning is a relatively new and faster method of conversion of discrete fibres into continuous staple yarn and, subsequently, various textiles and garments. Its yarn is distinct and a bit different compared to the conventional ring yarn. It has got wide acceptance in the market and fashion. As such, the spinning sector that converts fibres into yarns is an important industry world over, providing employment to many. Besides, being the basic operation in the fibre value chain, it supports many downstream activities, including human clothing and fashion. Thus, the research on rotor spinning, particularly the yarn engineering to produce better products will be helpful to strengthen and grow the textile value chain. Originality/value This is an original research study. The magnitude and the direction of the air drag on the yarn during rotor spinning is very difficult to assess. Thus, most researchers for the sake of simplicity in analysis have neglected its effect on yarn dynamics, but a few of them have taken note of it in their theoretical propositions. However, no experimental result has been reported so far in the literature, supporting the influence of such air-drag force on yarn tension in the rotor spinning. In fact, none of the above studies have considered the induced effect of centrifugal force caused because of the rotation of the opening roller on the airstream that flows from the transfer channel inlet into the rotor because of its partial vacuum, causing consequential effects on air-drag force and tension in the yarn inside the rotating rotor. This is the first of one-of-a-kind experimental study being reported to demonstrate the influence of air-drag force on yarn tension during the rotor spinning under dynamic condition.