Hole Diameter Research Articles

Numerical simulation of basic oxygen furnace rotating tapping

The rotation speed of the basic oxygen furnace (BOF) and the shape of the tapping hole have an important influence on the amount of slag carryover during the tapping process. The CFD fluid simulation software Fluent is used to analyze the flow field of the 210 t BOF rotation tapping process. The results revealed that the amount of slag carryover in the early stage is the largest when the tapping hole inclination angle is 0° and the rotation speed is 1.0 r/min. The flow field analysis shows that this is caused by the fluctuation of molten steel and slag, which makes the slag flow into the tapping hole again. The case of a rotation speed of 1.2 r/min shows the least amount of slag carryover. By comparing the three kinds of tapping holes, it can be known that a reduction in the tapping hole diameter brought a decrease in yield loss and a decrease in amount of slag carryover. As the height of molten steel decreases, the shear stress on the tapping hole decreases. The increase in the diameter of the tapping hole increases the shear stress, which in turn increases the wear of the refractory material.

Design and Laboratory Experiments of A Pneumatic Disc-Type Garlic Precision Seed-Metering Device

Highlights A novel pneumatic disc-type garlic precision seed-metering device was designed. Numerical simulations of the airflow field inside the seed-metering device were carried out with FLUENT Software. The diameter of the suction hole, the rotational speed of the seed plate, and negative pressure were used to evaluate the performance of the seed-metering device. The reasonableness of the optimal combination of parameters was verified by a bench experiment. Abstract. To solve the problem of high seed damage rate and low transplanting efficiency on traditional mechanical garlic seed-metering devices, this article designed and experimented with a novel pneumatic disc-type garlic precision seed-metering device by using theoretical calculations and orthogonal experiments. The overall structure of the device and the basic principles of each working stage were described. Numerical simulations of the airflow field inside the seed-metering device were conducted with FLUENT software to determine the optimal location of the negative pressure outlet and the number of suction holes. A three-factor, three-level Box-Behnken quadratic rotation orthogonal combination experiment was carried out to evaluate the performance of the seed-metering device in terms of the qualified index, miss index, and multiple index. The results showed that the optimal combination of parameters was a suction hole diameter of 10.03 mm, a rotational speed of 11.70 rpm, and a negative pressure of 7.02 kPa. With the optimal combination of parameters, the seeding qualified index was 88.04%, the miss index was 8.65%, and the multiple index was 3.31%, which met the design requirements. The results of the bench experiment were basically consistent with the results under the optimal combination of parameters. This design can provide a theoretical basis for garlic’s precision transplanting. Keywords: Airflow field, FLUENT, Garlic’s precision transplanting, Orthogonal combination experiment, Seed-metering device.

Matching method of flat layered-uniform lenses

A novel matching method of flat layered-uniform lens antennas is suggested, which assumes introducing the matching layers on both surfaces of the lens. The evaluations of the layers parameters are obtained on the base of simultaneous satisfaction of the focusing condition and the matching condition. The proposed method provides matching of flat layered-uniform lenses in which the required radial dependence of effective dielectric constant is achieved due to the perforation of through holes in dielectric plate following to the certain law. The matching layers may be implemented by means of drilling on the certain deep the holes of larger diameter on the existing holes in the dielectric plate. The full wave analysis of matched and unmatched flat lenses undertaken by means of finite integration method confirms the reduction of power losses caused media mismatching. In the case of flat lens with the diameter and the focus distance equal to 5λ and the thickness of dielectric plate equal to λ the improvement of the lens matching provides increasing of gain by 2 dB within frequency band 13%. The side lobe level including back lobes is reduced by 10…20 dB.

The stress state of a plate with several holes under the action of axial tensile load

The purpose of the research is to develop a numerical method for determining the stress state of plates with several holes. The research approach is based on the development of the superposition method for singular solutions. The study objective is to solve a practical problem of determining the stress concentration coefficients in a plate with two holes of the same diameter. The study uses the numerical method of elasticity theory in the form of a superposition of four special solutions, each of which lies entirely within the corresponding hole contour. The resulting contour integrals in the displacement formula are replaced by their approximate values using the M-point trapezoidal formula or the Gaussian quadrature formula. Equating to zero the expression in variations of unknown constants (the principle of minimum potential strain energy), we have obtained a system of linear algebraic equations 4MN of unknown distribution densities. After determining the constants using known formulas, the stress-strain state of the plate with holes can be calculated. The error of the developed method is no more than 0.6% compared to the known solution.

Selection of an optimal set of machines for sorting and crushing municipal solid waste

The article is dedicated to the selection of the optimal set of machines for sorting and crushing municipal solid waste based on its properties and accumulation rates. Considering the properties of waste and technologies for its collection, a new technological scheme for processing municipal solid waste was developed and, based on this scheme, the optimal set of machines was selected. In addition, the research conducted to determine the fractional composition of the waste made it possible to substantiate the diameter of holes in the drum screen mesh. Based on the analysis of the morphological composition of the waste at the end of the technological chain, the type of crusher design was determined and the main parameters of the hammer crusher were substantiated in connection with the technological processing. The optimal set of machines will make it possible to process the components of municipal solid waste for use in the form of secondary raw materials with the least material and time costs.

Estimating, appraising and establishing blast exclusion zone at Huni pit - A case study

The issue of accidental flyrock has the tendency to develop safety concerns for commuters around the main public road as mining progressed from 960 ​m reduced level (RL) to 912 ​m RL at Huni pit in Ghana. An evaluation was carried out using empirical models and an artificial neural network to assess and determine the safest blast exclusion zone. The calculations showed that the flyrock could travel a maximum of 220 ​m and 277.45 ​m horizontally for blast hole diameters of 115 ​mm and 127 ​mm, respectively, with the same stemming length of 2.0 ​m. The distances to the public road are much farther than these projected maximum horizontal distances. An artificial neural network (ANN) was also employed to predict the flyrock distance and it was found that the ANN model has the best root mean squared error (RMSE) value of 0.0012 and the highest coefficient of determination (R2) value of 0.99 for the flyrock throw prediction. Hence, the blast exclusion zone has been reduced to 500 ​m all around the pit from the pit crest satisfying the recommendation suggested by the Minerals Commission of Ghana. With the new blast exclusion zone, travelling from Damang through Akyempim to Twifo Praso, Takoradi, Cape Coast, and Accra during blasting times is no longer a bother.

Determination of Tool Wear Drilling Process of Aluminum 6061 and Brass C3604 by using CNC Robodrill Machine

Hole making process is a stimulating process as it impacts the drilling tool’s performance and wear. The main objective of this paper is to determine the drilling tool wear by using step-by-step drilling approaches used by most of the manufacturing companies. Two types of materials involved; Aluminum 6061 & Brass C3604. Firstly, the raw material grade was confirmed by testing it using an Oxford Spectrometer. Four types of drilling tools are used; center drill diameter 3.00 mm; drill diameter 10.00, 13.00 and 14.50 mm. The drilling tool material used is High-Speed Steel (HSS). The cutting parameter used is stated in detail in the methodology section. Two approach are used to determine the tool life; measuring the holes diameter produced by using Vernier caliper; graphical form with the help of the camera. The major finding of this research is the understanding on how the cutting process react with the drilling tool during the cutting process as discussed in the results and discussions. The tool life of a center drill, drilling tool diameter 10.00 mm, 13.00 mm and 14.50 mm in drilling Aluminum 6061 is 476, 250, 485 and 499 holes while for Brass C3604 is 360, 190, 360 and 375 holes.

PCF-based Sensors for Biomedical Applications-A Review.

The article provides a comprehensive overview of the current and future advances of Photonic crystal fiber (PCF) based biosensors, the research explores the impact of structural parameter variations on phase matching conditions, by investigating pitch, air hole diameter, and gold layer thickness. Currently, these surface plasmon resonance (SPR) biosensors demonstrate the ability to detect a range of biological substances such as glucose, pH, serum proteins, and similar chemicals. They have the capacity to directly identify bio-components in urine, blood, and saliva, as well as pathogens, bacteria, and contaminants in food, water, and air. The study investigates by presenting the fundamental principles of PCF biosensors, highlighting their comparative benefits over conventional biosensors. Recent studies utilizing PCF biosensors for various application are reviewed, the findings of the review suggest that the integration of SPR enhances the sensing capabilities of these biosensors, making them promising tools for diverse applications in the field of biosensing.

Deterministic positioning of few aqueous colloidal quantum dots.

Emerging quantum technologies that critically require the integration of quantum emitters on photonic platforms are hindered by the control over their position, quantity, and scalability. Herein, we describe a facile strategy to deposit aqueous silica-coated quantum dots (QDs) in a template of polymethyl methacrylate (PMMA) nanoholes that leverages saturated ethanol vapor drop-casting and subsequent lift-off of the template. Ethanol vapor incorporation into water droplets during the drying process reduces the meniscus contact angle, which increases capillary forces and enhances particle confinement within the pinning contact region. Furthermore, induced Marangoni flow controls the particle transport dynamics inside the droplets, making large-scale deposition possible. Controlling the hole diameter of the template demonstrates changes in the number of QDs per hole, which is consistent with the Poissonian distribution with the best results of ∼40% single-particle yield from an ∼80% total site occupancy. This method employs a simple setup, eliminating the need for intricate optimization, yet offers the potential for deterministic patterning within complex photonic platforms.

Characterization of diesel spray with novel high-speed laser absorption scattering technique under diesel engine-like condition

In Diesel Engines, the injection process plays a decisive role in the combustion efficiency. Hence, the characterization of diesel sprays is very important. Several methods are developed, however, none of them records the temporal fuel distribution throughout the individual injection event and measures the liquid/vapor concentration of an evaporating diesel spray. In this work, two light sources i.e., an ultraviolet LED and a continuous wave laser, were used with two high-speed video cameras. A fuel mixture with the compositions of 97.5 % n-tridecane and 2.5 % of volume-based 1-methylnaphthalene was selected as the test fuel. The fuel was intermittently injected into an inert environment at 4.8 MPa and 800 K by applying a seven-hole injector with a hole diameter of 0.123 mm. The injection pressure was set at 100 MPa and the injection amounts were set as 2.5 and 5.0 mg/hole to observe the effect of the injected mass on the spray characteristics and mixture formation process. Calibration, based on the scattering by non-evaporating sprays and molar absorption coefficients for fully evaporated sprays, indicates a measurement error of 15 %. The findings of the experiments show that, under large injection mass conditions, the liquid phase equivalence ratio is quite low and close to zero just after the end of injection which points out that as the air-fuel mixing quality improves, the majority of the liquid fuel is rapidly converted to vapor. The air-fuel mixture is overall richer at large injected mass compared to the small mass condition. Furthermore, after the end of injection, the high fuel vapor concentration area near the nozzle soon mixes with ambient gas, decreasing the equivalence ratio to low levels, whereas a high-vapor-concentration region is still present at the spray head. This study provides a valuable insights into the behavior of the fuel spray, which could be used to improve the efficiency and performance of diesel engines.

The fluidic molecular trajectory and the Nano-droplet production ability

This paper studies the liquid Nano-droplet production ability using molecular dynamics simulation methodology. The research parameter is performed at the temperature of 310 Kelvin (K), the pressing force of 10.0 × 10−10 Newton (N) and the ejective hole diameters of 25 and 40 Angstrom (Å). The research result shows that liquid Nano-droplets finally were not produced for the ejective diameter of 25 Å. The Nano-jets were not only non-destruction from nozzle’s surface to produce the droplets but also movement downward to come back the nozzle’s surface. The molecular trajectory is very zigzag and curved both inside and outside the ejective container. In the contrary, when increasing the ejective diameter to 40 Å, the liquid Nano-droplet was produced in the same the ejective time and compressible force magnitude. The molecular trajectory is quite straight after ejecting out the outside of the container. Meanwhile, for the nozzle diameter size of 40 Å, the Nano-droplet was not only production but also movement up to leave away the nozzle’s surface under same above conditions. That proves that the ejective diameter has the influences to the moveable direction and Nano-droplets formation ability in the whole ejective process.

Effect of film hole diameter and attack angle on the film cooling performance of leading edge with double swirl chamber under crossflow condition

The film cooling characteristics of the blade leading edge with a double swirl chamber are studied experimentally under crossflow(CF) conditions. Aerodynamic and structural parameters such as CF intensity, blowing ratio(BR, 0.5–1.5), film hole diameter(df, 2–4 mm), and attack angle(αa, 0-16°) are considered comprehensively in the experiment. The computational simulation method was introduced to reveal the mechanism of CF affecting the cooling performance. The results present that introducing the CF condition at the same BR condition led to BR redistribution in the film holes, significantly improving the cooling protection near the C1 film holes for the df=3 mm and df=4 mm cases. Unlike the adverse effects of CF on the heat transfer in previous studies, the results present that CF under low BR conditions can help avoid the mainstream intrusion of the film holes. In the case of αa=8° and 16°, The film cooling effectiveness performs the highest in the CF0-BR1.0 condition at s/df>8, and the equivalent film coverage can be obtained under the CF1-BR0.5 condition. CF at αa=8° similarly avoids the mainstream intrusion under the small BR, but the CF reduces η near the C2– film holes. In contrast, the CF has little effect on the cooling performance around the C2– film holes in the case of αa=16° under BR=0.5. The area-averaged film cooling effectiveness of CF2-BR0.5 improves by 85 % relative to CF0-BR0.5 at df=3 mm case. When df=4 mm, the area-averaged film cooling effectiveness enhancement of the CF1-BR1.0 condition is about 87.43 % higher than that of CF0-BR1.0.

Effect of hydrogen injection hole diameter on the burning condition of a lifted flame in a hydrogen burner

Effect of hydrogen injection hole diameter on the burning condition of a lifted flame in a hydrogen burner

Millisecond fibre laser drilling of alumina-alumina CMC

Alumina-Alumina (OX-Ox)CMCs are a technical ceramic composed of alumina fibres in an alumina matrix, with a primary usage case in the aerospace industry. Ox-Ox CMCs offer the traditional benefits of high toughness and bending strength, along with resistance to oxidation and corrosion associated with monolithic alumina, coupled with low brittleness and crack arresting behaviour of fibre in matrix composites. Whilst these properties are highly desirable, CMCs present significant difficulties for conventional mechanical machining, with laser machining offering potential solutions providing the impetus to the work presented in this paper. This work presents a parametric study of the effects of frequency and pulse energy for 10mm deep laser percussion drilled holes and a response surface study for these two variables, using an industrially representative 20kW peak power laser. Results show that for an 800µm diameter hole, a taper angle of <1⁰ and average recast layer thickness of <40µm are achievable, while the response surface study highlights the importance of considering input variables as a complex system, particularly for recast layer thickness.

Silica-based ceramic cores for high-pressure turbine airfoil blades in aircraft engines

Ceramic cores for high-pressure turbine airfoil blades in aircraft engines are characterised by very complicated shapes and the presence of small diameter holes and thin long grooves. In this paper, eight starting powder mixtures having different contents of fused silica, zirconium silicate, alumina and borosilicate glass were used for preparation of core material. The composition, which satisfies every demand for core application in the investment casting of high-pressure turbine blades, contains 69.0wt.% fused silica, 13.0 wt.% zirconium silicate, 12.0wt.% alumina and 6.0wt.% borosilicate glass. This material was characterised by a mechanical strength of 33.1MPa, a coefficient of thermal expansion of 2.56 ? 10?6 1/K, surface roughness of 1.8 ?m, shrinkage of less than 0.8% and an average pore size diameter of 2.7 ?m. The thin-walled ceramic cores were formed by the high-pressure injection moulding method, which required the selection of a thermoplasticiser, feedstock formulation and determination of the optimal processing conditions protecting the injected cores from defects and deformation. The post-shaping process of the cores included both water and thermal debinding, sintering, precision machining and dimension measurements.

烟草打塘-移栽一体化装置的设计与优化

To overcome inadequate functional integration, irregular pits, and insufficient agricultural machinery and agronomy in tobacco seedling transplanting equipment under film, a digging transplanting integrated machine was built. The machine uses parallel four-bar mechanism. The excavation equipment uses conical spiral blades. Using the trajectory approach, the four bar mechanism's fundamental parameters can be reversed. This method meets the requirements for coordinated excavation and transplantation. Mechanical study of soil units determines upward movement characteristics. Additionally, spiral angle, spiral blade outer diameter, and spiral blade speed are quantified to affect soil movement. The range of factors is derived. Based on three factors binary regression orthogonal combination simulated optimization experiment, a discrete element analysis was performed to enhance parameters. Experimental factors optimized include a spiral angle of 19°, a spiral blade diameter of 378 mm, and a rotational speed of 258 rpm. The two optimized test indicators are: a 193 mm hole depth and 350 mm hole diameter. The improved results were verified by field validation studies using a 191 mm hole depth and 347 mm hole diameter. The simulation optimization results and field validation experiment results are very similar. This study provides a technical basis for tobacco farming concurrent drilling and transplanting research.

Changes of the morpho-functional parameters of the retina of patients after surgical treatment of rhegmatogenous retinal detachment complicated by macular hole in the early postoperative period

Objective: to realize the effectiveness of surgical treatment of patients with retinal detachment and macular hole PVR C, depending on the method of closing the macular hole. Material and methods. The data of 20 patients (20 eyes) with a diagnosis of retinal detachment with macular hole PVR С were studied. Patients of the 1st group (10 patients, 10 eyes) underwent surgical treatment with closure of the macular hole with an inverted flap of the inner limiting membrane. Patients of the 2nd group (10 patients, 10 eyes) did not undergo closure of the macular hole during the first stage of surgical treatment. Results. In the 1st group, it was possible to achieve closure of the macular hole in 80% of cases. In the 2nd group, a day after the operation, there was a significant decrease in the diameter to 263±46 urn. When re-examined a month later, in 80% of cases, the macular hole was closed. When studying the results of micro-perimetry one day after the operation, positive dynamics was noted. While after a month of observation, the indicators of patients in the second group were significantly higher. Conclusion. The method of surgical treatment of retinal detachment with macular hole showed greater efficiency in refusing to perform membranopiling; in patients of this group, higher functional results were achieved. During the observation period, cases of a decrease in the diameter of an intact macular hole and its complete closure under the action of silicone tamponade were recorded. If necessary, membrane peeling can be delayed during a second silicone oil removal operation.

LIQUID-SOLID COUPLING RESPONSE OF SURROUNDING ROCK MASS OF LARGE-DIAMETER RIVER-CROSSING SHIELD TUNNEL

The purpose is to investigate the response of seepage field, displacement field and stress field in the surrounding rock mass during dynamic tunneling in soft soil area. Relied on a large-diameter river-crossing shield tunnel project, considering driving force, shield tail grouting pressure, and the friction resistance between the shield shell and the soil, a three-dimensional fine tunnel model considering the liquid-solid coupling effect in the soil during dynamic tunneling was established by employing the finite difference method. The response characteristics of pore water pressure, displacement and stress in the surrounding rock mass were obtained. The results show that during shield tunneling and shield tail grouting, the pore water pressure in the range of 0.5 times the hole diameter around the tunnel decreases and increases respectively due to the liquid-solid coupling in the surrounding rock mass. When the shield tunneling moves away, the pore water pressure of the soil near the vault decreases, and the pore water pressure near the tunnel arch bottom increases. The impact range of shield tail grouting on the vertical settlement of the upper soil is about 0.5 times the hole diameter. The shield tail grouting can effectively reduce the vertical settlement of the top soil and slow down the vertical uplift of the bottom soil. During shield tunneling the vertical stress distribution of the soil above the vault of the working position and around the excavation surface is funnel-shaped, and the vertical stress around the excavated tunnel decreases.

تأثير حجم الدقائق وقطر ثقوب القالب في الآلة على نوعية الحبيبات العلفية لدجاج اللحم

Due to the need for controlling and regulating of feed pellet. Pellet that is imported or locally manufactured is accompanied by cracking and crumbling percentage that occur during transporting and distributing to animals, using conveyors and mechanical feeders. This study aimed to determine the effect of particle size and die holes diameter in the machine on broiler feed pellets quality in pellet durability, pellet direct measurement, pellet expansion, and pellet length. Three particle size 2, 4, and 6 mm, and three diameters of die holes in the machine 3, 4, and 5 mm, have been used. The results showed that changing the particle size from 2 to 4 then to 6 mm led to a significant decrease in pellet durability and pellet lengths, pellet expansion was increased, whereas it did not significantly effect on pellet direct measurement. Increasing the die holes diameter from 3 to 4 to 5 mm led to a significant decrease in pellet durability, pellet direct measurement and pellet lengths, increased pellet expansion. The particle size of the diet 2 mm and die holes diameter of 3 mm recorded the highest pellet durability at 93.40%, pellet direct measurement at 95.12%, pellet lengths at 86.96%, and less pellet expansion at 0.88%. The minimum particle size and die holes diameter gave the highest pellet durability, pellet direct measurement, pellet lengths, and lowest pellet expansion with all the considered indicators.

A new approach to the treatment of central retinal detachment with a macular hole in patients with extreme myopia and scleral staphyloma

Purpose. To develop a methodology of surgical treatment of central retinal detachment with macular holes of various diameters in patients with high myopia and scleral staphyloma using autologous conditioned plasma (ACP) as a rupture blocking composite and pneumoretinopexy as the final tamponade, and analyze the results of this treatment.Material and methods. The surgery included subtotal vitrectomy 25+, 27G, peeling of the inner limiting membrane, pneumoretinopexy, introduction of ACP into the area of scleral staphyloma through the macular hole, and, upon the formation of a plasma seal at the base, applying ACP to the retinal surface in the area of the hole in 2–3 layers until a stable ACP film could be formed. The operation was completed seamlessly, blocking the sclero-conjunctival access by applying 2–3 layers of ACP to the scleral surface and the conjunctiva. Using this technique, we operated 25 patients aged 29–69 with central retinal detachment and macular hole with a width of 700–2200 μm who had high myopia and severe scleral staphyloma.Results. In the early (on days 2 and 4) and the late postoperative period, the retina was completely attached, and the macular hole was blocked in all patients.Conclusion. This technique is maximally sparing and highly effective. It allows achieving full anatomical retinal reattachment and closure of the macular hole, eliminates the need for silicone tamponade, minimizes the risk of postoperative complications in patients with central retinal detachment, macular holes of various diameters, high myopia and scleral staphyloma.