Search

IntroductionThe overflow structure is used to organize and control the water level in open canals and relaxation ponds. Composite sharp edge overflows are designed in different ways and are made up of several openings in such a way that when there is a shortage of water, The flow only passes through the main section of the spillway and more discharge is created on it, and during the flood, with the increase of the discharge, the upper section also starts working, and as a result, it prevents the return of water and the increase of the water level upstream of the spillway. In this situation, the measurement is done with more accuracy (Boss, 1988). Due to the ability to control the water level and the ease of construction and measurement of flow intensity, sharp edge spillways and sliding gates have been widely investigated. On the other hand, most of the overflows in their upstream cause the formation of a region with relatively still water, which creates favorable conditions for sediments and waste materials to settle in the water, which is considered one of the defects of this structure. With the combination of overflow and gate, the difficulties and disadvantages of using each one alone can be reduced so that materials with sedimentation properties are easily emptied from the gate part and mineral and floating materials are emptied from the overflow (Negm et al, 2002).MethodologyThe experiments of this research were carried out in the hydraulic laboratory channel of the Faculty of Agriculture of Birjand University. The channel used in this experiment has a rectangular cross section with a width of 0.3 meters, a length of 10 meters, a height of 0.5 meters and a maximum flow rate of 30 liters per second. The current research was carried out in the form of establishing flow with constant opening of the gate and different flow rates, as well as establishing flow with opening of different gates and constant flow rate in two slopes of 0.004 and 0.002 to determine the flow coefficient. In order to carry out the present experiment, a semi-circular-rectangular overflow structure and a sliding gate is made of galvanized sheet and installed in the test section.By including all effective parameters and dimensional analysis by Buckingham’s method and considering ρ, v and y as repeated variables, the general equation of dimensionless parameters is obtained as follows after simplification. In the present study, dimensionless parameters Hg/D, y/D and were investigated.Results and discussionAccording to the collected data and the hydraulic and geometrical parameters of the structure, the discharge coefficient of the structure was investigated. The flow coefficient of the combined structure was calculated in two states of constant gate and different flow rates, and constant flow rate and different gates. Also, in order to control some of the experiments, the discharge coefficient of the combined structure was investigated in two slopes of 0.004 and 0.002. In all these researches, the discharge coefficient of the combined structure was between 0.6 and 0.8.ConclusionThe test results show that the discharge coefficient depends on whether the gate is submerged or not and the height of the upstream water. Also, the flow coefficient in the conditions of water passing through the gate decreases with the increase of Y/D parameter, and the flow coefficient increases with the increase of Y/D when water passes through the gateand semi-circular-rectangular overflow. By changing the slope of the floor, the discharge coefficient has not changed significantly and with the decrease of Hg/D, the discharge coefficient is almost fixed and tends to a constant number of 0.74.

Al 2 O 3 -Ti 2 O 3 -Al sliding gates were prepared from Al 2 O 3 -Ti 2 O 3 raw materials, sintered corundum and aluminum, and used in trials at steel works. The sliding gate with 30 wt% Al 2 O 3 -Ti 2 O 3 added was used on an 80 t ladle for 4 cycles without macrocracks. The postmortem sliding gate can be divided into the permeation layer (0–0.1 mm), transition I layer (0.1–10 mm), transition II layer (10–20 mm) and unchanged layer from the hole working face outward. XRD, SEM and industrial CT were used to analyze the postmortem sliding gate. The results show that, in the Al 2 O 3 -Ti 2 O 3 -Al sliding gate, both Al and Ti 2 O 3 are involved in reactions, Ti 2 O 3 transforms into Ti 2 O and TiO in the transition I layer, and part of the Ti 2 O 3 in the transition II layer transforms into Ti 8 O 15. Titanium compounds with different densities are dispersed in the matrix and form microcracks to improve the thermal shock resistance of the sliding gate, which improved the performance. [ABSTRACT FROM AUTHOR]

The gate is a means of dividing the land between the house and the road. The gate also serves for security and comfort as a place to live. As a home security, the gate is made high and equipped with a safety lock. With a gate, you will feel comfortable because other people who come can't enter the house directly, and it's often difficult or overwhelmed when opening or closing the gate. In the case of a gate that has a large size and is also heavy, this will overwhelm us so that a lot of energy and time is needed. The automatic gate control device designed is an electric motor that makes it easier for people to open or close the gate by remote control while at home or at work. Based on the results of the design that has been made, the simulation of the automatic sliding gate control device is expected to solve the problems encountered in the field where the dimensions of the gate are 1500mm x 1000mm x 80mm with a weight of 27kg, the electric motor used is reversible AC which has a speed of 1300 RPM, a power of 60 watts and a 1: 60 gearbox which has become 1 part, the speed of the electric motor is transmitted by a gear with a diameter of 78mm, so that the average gate opening and closing speed is 12.52 and 13.21s with a difference of 0.69s, with the The controller used is the AK-T02 module and the AKJ027 remote can work up to a distance of 10 m. It is hoped that making this control device simulation can be a reference in making automatic gate control devices for homes and other gates.

Severe variability of fresh feed ore flowrate in a crushing circuit may cause some operational damages. Related issues include conveyor belt and sieves overload, interlocked crushers, early equipment wear, and silos overflow. Usually, the speed of feeders is used to control the ore output from silos; however, it is ineffective in regulating the height of material carried by the feeder. The introduction of a slide gate in the primary silo of the crushing circuit is an alternative to increase the degree of freedom for controlling the fresh ore flowrate. This paper presents a numerical simulation using a discrete element method (DEM) applied in a silo-gate-feeder system. The simulated model is based on parameters from a Vale's iron ore beneficiation plant located in Serra Leste Mine, city of Curionópolis, Brazil. The simulation was carried out using the software Siemens Star CCM+ ®. Three scenarios were evaluated, such as changes in the slide gate aperture. The results show that regulating the feeder speed simultaneously with the gate aperture provides a novel control strategy to reduce variability in fresh ore flowrate. The best simulation result reduced in about 11% the variability flowrate compared with the case with no slide gate. [ABSTRACT FROM AUTHOR]

Abstract A novel porous ferrosilicon nitride (Fe 3 Si–Si 3 N 4) ceramic sliding gate was prepared and applied in a ladle in a steel mill; it was characterised by X-ray diffraction analysis, scanning electron microscopy, and energy-dispersive spectroscopy. The results showed that after use, the sliding gate consisted of a reaction layer (0–1.5 mm), a transition layer (1.5–2.2 mm), a gradient layer (2.2–20 mm), and an unaltered layer. In the reaction layer, Si 3 N 4 is decomposed, and the structure is damaged; in the transition layer, Si 3 N 4 is stable, and the structure shows no obvious change; in the gradient layer, Si 3 N 4 is oxidised slightly. The reaction mechanism is as follows. The structure of the original porous ferrosilicon nitride resembles a sea urchin, and β-Si 3 N 4 columns are bundled together by Fe 3 Si. During operation, Fe 3 Si reacts with molten steel to form an Fe/FeSi melt, which attacks the structure, whereas Si 3 N 4 decomposes to the product N 2 (g) [ Si 3 N 4 (s) + F e (l) → FeSi (l) + N 2 (g) ]. N 2 (g) forms a high-pressure gas cushion that blocks the molten steel, protecting the inner part of the sliding gate, so Si 3 N 4 remains stable in the transition layer. Further inward, Si 3 N 4 is oxidised slightly by trace [O] from the molten steel to generate silicon oxynitride. The reaction model was established. Highlights • A novel porous ferrosilicon nitride ceramics sliding gate performs well. • β-Si 3 N 4 columns are bundled together by Fe 3 Si resembles a sea urchin. • During operation, Si 3 N 4 reacts with molten steel and decomposes to product N 2 (g). • N 2 (g) forms a high-pressure gas cushion, protecting the inner part of the sliding gate. [ABSTRACT FROM AUTHOR]

The existing seeding devices not fully provide quality of application of mineral fertilizers. Unevenness and instability of application reach 20–40% at demanded to 15%. It, first of all, associated with the absorption of fertilizers and imperfection of seeding devices for fertilizer. For a solution of the problem of ensuring quality of application of mineral fertilizers at their intra soil differentiated application the original design of the pin reel of a seeding device is offered. Pins of the reel are executed in the form of the tetrahedral truncated pyramids located on crossing right and left multiple-helical lines on a reel surface. Theoretical researches relied on regularities of classical mechanics. As a result of theoretical researches the expression connecting all key design and technological parameters is received: reel radius, number of pins on it, their height and the sizes of the top and lower basis, diameter of a driving wheel, rate of application, aisle width, and transfer ratio of the driving mechanism.

Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Carbon free Al–Al 2 O 3 composite sliding gate materials were successfully prepared by adding excess amount of Al powders through carbon burial sintering at 1450 °C for 6 h. Physical properties including apparent porosity, bulk density, ambient temperature crushing strength and hot rupture modulus were characterized for all the samples and addition of 9 at% aluminum powder was proved to exhibit optimal properties. The XRD and SEM results reveal that Al 4 O 4 C and AlN phases shown in the product samples are serving as reinforcement phase, contributing to better physical performances. [ABSTRACT FROM AUTHOR]