Influence of the parameters of deforming cutting on the features of the resulting slotted filter structures

Introduction. Slot filters are in demand in petrochemical, machine-building, food, mining and other industries. DC is an edge cutting machining method based on undercutting and plastic deformation of the workpiece’s surface layer without its removal in the form of chip. DC stands out from the other slot structure forming methods for its capability of obtaining fine filters (slot width upwards of 20 µm) while maintaining relatively high productivity rate and being waste-free. Nevertheless, patterns of through slots cutting by means of DC had virtually not been investigated previously. The purpose of the work is to establish the influence of the main parameters of deformational cutting, namely feed and depth of cut, on features of through slots obtained, as well as identifying combinations of parameters that ensure the production of structures suitable for filtration. Method of investigation consisted of experiments on through-cutting of corrugations stamped on copper strips and a visual analysis of the structures obtained. Cutting through the corrugations by DC was conducted on a lathe while using a special attachment – a barrel which workpiece corrugated strips were wrapped around and fixed on with tension. Results and discussion. The resulting typical structures obtained under different combinations of depth of cut and feed are systemized and divided into the following groups: “0” – the absence of the through cut; “1” – uniform slots; “2” – “twinning” (pairwise convergence of slot walls), “3” – stripping of every second slot wall; “4” – non-regular or complete stripping of slot walls; “5” – uniform slots with a continuous burr (“skirt”) formed along the slot row on the internal side of the corrugation; “6” – uniform slots with a “skirt” opened incompletely. In the range of feeds 0.2 ... 0.4 mm/rev with increasing cutting depth, there is a transition from structures of group “1” to structures of group “2”, and the greater the feed, the greater the maximum depth of cut, at which uniform slots remain. Group “1” is assigned to the area of structures suitable for filtration applications, although it is characterized by the formation of individual burrs on the inner side of each slot. At lower feeds (up to 0.2 mm/rev) with further increase of the depth of cut another group of structures potentially suitable for filtering purposes is reached: groups “5” and “6”. With the “skirt” formed, individual burrs next to each slots are absent, and the shape of slots is cleaner. With a decrease in feed, the width of the resulting slots decreases. The least tool feed value, at which uniform slots are obtained, is 0.05 mm/rev which corresponds to 19 µm slot width. Establishing the causes of “twinning” and the formation of “skirts” requires further investigation.

A Case Study of Turbulent Free Jet Flows Issuing from Rectangular Slots on Process Performances and Quality of Hot-Air-Dried Apple

This study deals with the improvement in drying process performances and the quality of the final product for industrial equipment in the food industry. Designers need to optimize the design parameters of devices to create synergies between the greater energy efficiency of the process and high-quality dried products. Air impingement drying was carried out on apple cylinders at 323 K and with air velocities ranging between 30 and 60 m s−1. The studied drying process presents a particular setup of jets as they are multiple rectangular slot jets issued from triangular nozzles. The effect of four design jet parameters (slot width, nozzle-to-surface height, nozzle-to-nozzle spacing, and airflow) on the drying process performances and the quality of the final product was analyzed and optimized using response surface methodology (RSM). A minimal influence of design jet parameters on the process performances was shown, while an important impact was observed on the quality of dried apple. The slot width and the nozzle-to-nozzle spacing had a significant effect on the textural and functional properties. Predictive models were established and good agreements were found between predictive and observed values. Sorption isotherms were properly modeled by the Guggenheim–Anderson–de Boer (GAB) model.

High-Q Slot Resonator Used in Chipless Tag Design

A retransmission chipless tag with multiple U-shaped slot resonators is proposed to cut down the cost of traditional tags with chips. Multiple side-by-side U-shaped slot structures of different lengths are printed on the microstrip line, and the two terminals of the microstrip line are connected correspondingly with two orthogonal ultra-wideband (UWB) transceiver antennas to form the retransmission chipless tag. The U-shaped slot resonator has high Q values and narrow impedance bandwidth. The bandwidth that each resonator adds to the protection bandwidth is 300 MHz. Several 6-bit coding U-shaped slot resonator chipless tags are designed and fabricated for comparison and measurement. Results show that the simulation and the measurement are in agreement. The slot width of the U-shaped slot resonator and the distance between the resonators are reduced, resulting in deepened spectrum notch depth of the resonator. Decreasing the dielectric constant of the substrate or increasing the thickness of the substrate increases the spectrum notch depth of the resonator.

Numerical analysis and experimental verification of magnetic fluid sealing for air cylinder in Aerospace Engineering

In order to solve the problem of short service life (2 months) and zero leakage of air cylinder in aerospace engineering, this paper innovatively designs a magnetic fluid sealing device of air cylinder in aerospace engineering through magnetic circuit analysis and magnetic fluid sealing theory. The magnetic field finite element method is used to calculate the magnetic field distribution in the sealing gap under different key parameters such as the number of pole teeth, the height of the radial sealing gap, the thickness of the permanent magnet, the slot width, the ratio of pole piece height to shaft. And numerical analysis of the number of pole teeth, the radial sealing gap height, permanent magnet thickness, slot width, the ratio of pole piece height to shaft and other key parameters on the magnetic fluid sealing performance. Finally, the reliability of the reciprocating magnetic fluid sealing withstand voltage is verified by experimental methods. Research indicates. The pressure capabilities of magnetic fluid sealing is increasing with the increase of the number of pole teeth. The pressure capabilities of magnetic fluid sealing is decreasing with the increase of the radial sealing gap. The sealing withstand voltage increases first and then decreases with the increase of the thickness of the permanent magnet, and finally increases, and the value of the withstand voltage is the largest when the thickness of the permanent magnet is 7.8 mm. The sealing pressure capabilities increases as the slot width increases. The sealing withstand voltage increases first and then decreases as the ratio of pole piece height to shaft increases, and when the ratio of pole piece height to shaft is 0.8, the sealing withstand voltage reaches a maximum value. The pressure test finally reaches the pressure value of 6 MPa, which can meet the pressure value demand of medium pressure cylinder, indicating that the magnetic fluid sealing technology can effectively solve the leakage problem existing in the air cylinder technology of Aerospace Engineering, and improve the reliability and service life of the air cylinder.

ELABORATION OF THE RESEARCH METHOD FOR MILK DISPERSION IN THE JET-SLOT TYPE HOMOGENIZER

The competitiveness improvement of milk products is directly connected with a problem of decreasing energy consumption of the process of milk emulsion dispersion. At creating promising types of energy effective dispersers, a necessary condition is to elaborate a correct methodology for studying them that takes into account the specificity of the process of fat milk microemulsion dispersion. Based on the critical analysis of research methods for homogenizers of different types, there have been determined main directions of their improvement, taken into account in the elaborated research method for a promising jet-slot type milk homogenizer. The method of theoretical studies, including a choice and analysis of stable and changeable factors of the homogenization process in a jet-slot type homogenizer and optimization criteria, has been elaborated. The interconnection of technological, constructive, hydraulic parameters with a dispersion quality has been demonstrated. The influence of physical-mechanical properties of milk as a research object was taken into account. An optimal milk temperature was chosen for the studies. Factor variation limits have been substantiated. The constructive scheme of a chamber for the experimental homogenizer has been developed. At processing the experimental research methodology, the main stage was to develop an experimental set for studying the influence of changeable factors of the dispersion process on a homogenization quality. Dispersion quality estimation methods have been analyzed and the method of microphotography has been chosen with further computed analysis of obtained data. The elaborated methodology was used at studying the influence of cream fat and ring slot width on a dispersion quality in a jet-slot type homogenizer. The obtained data allow to determine rational parameters of cream fat – 40–50 % and slot width – 0.1 mm. The analysis of dispersed characteristics of the milk emulsion allows to make a conclusion about the high homogenization quality, comparing with processing in a valve homogenizer

Study on the model of semi-open-end twist in compact spinning with lattice apron

The twist mechanism of the fiber strand in the condensing zone in compact spinning is complex. This paper proposes a dynamic model to evaluate the additional twist of the fiber strands. Based on the flow simulation in the condensing zone, the fiber trajectory in the suction slot was simulated and obtained. Several spinning parameters such as suction slot angle, suction slot width, negative pressure, and shape of suction slot, were varied to show their effects on the additional twist. The simulation results indicated that by increasing the suction slot angle from 5° to 10° the additional twist increased significantly. Higher negative pressure also leads to an increase in the additional twist. The suction slot width has a greater effect on the fiber trajectory than on the additional twist. An arc-shape suction slot increased the additional twist compared with a linear-shape one. An experimental test conducted revealed a precise agreement with the simulation results.

An Analysis of Slot Dimension Changing in Dual band Rectangular Patch Microstrip Antenna with Proximity Coupled Feed

In this paper, the characteristics of dual band rectangular patch microstrip antenna using proximity couple feed are studied. It can be used for a wireless device that works on multiband frequency. The addition of slot and proximity feed used in order to obtain larger bandwidth and multiple frequency. Microstrip antenna is designed and simulated using software also used to analyze by changing the variable of microstrip slot’s dimension. The parameters are tested in this study include Voltage standing wave ratio (VSWR), return loss, gain, bandwidth and radiation patterns. From the simulation results, the best value of return loss antenna is -23,29 dB at 2,4 GHz with a slot width of 1 mm and 0,085 GHz bandwidth. At 3,7 GHz, the best value of return loss antenna is -23dB with a slot width of 2 mm and 0,12 GHz bandwidth. Afterwards, the best VSWR obtained on dual band microstrip antennas with proximity coupled feed is 1,14 and 5.53 dBi gain.Keywords: slot, bandwidth, proximity, return loss, gain.

Effects of the Impeller Blade with a Slot Structure on the Centrifugal Pump Performance

An impeller blade with a slot structure can affect the velocity distribution in the impeller flow passage of the centrifugal pump, thus affecting the pump’s performance. Various slot structure geometric parameter combinations were tested in this study to explore this relationship: slot position p, slot width b1, slot deflection angle β, and slot depth h with (3–4) levels were selected for each factor on an L16 orthogonal test table. The results show that b1 and h are the major factors influencing pump performance under low and rated flow conditions, while p is the major influencing factor under the large flow condition. The slot structure close to the front edge of the impeller blade can change the low-pressure region of the suction inlet of the impeller flow passage, thus improving the fluid velocity distribution in the impeller. Optimal slot parameter combinations according to the actual machining precision may include a small slot width b1, slot depth h of ¼ b, slot deflection angle β of 45°–60°, and slot position p close to the front edge of the blade at 20–40%.

Collapse and Bending Analysis of Slotted Liners with Laboratory Tests and 3D FEM

Summary The goal of this research is to study the structural integrity and slot width change of slotted liners by comparing them with a 3D finite element analysis and experimental study. Slotted liners are widely used because of their ability to ensure wellbore integrity and sand control. During installation and operations, the slotted liners must be strong enough to hold axial loads and radial compression to prevent excessive buckling and deformation of slots. Laboratory collapse and bending tests were conducted with commercially available slotted liners. Experiments were designed to select the grades of materials, diameter/thickness of pipes, and slot patterns. Finite element models were developed to predict the integrity of slotted liners and acceptable slot width changes. The study considered slotted liner design and analyzed how much material grades, casing/tubing dimension, and slot patterns affect the risk of slotted liner failure. The practical implications of this work to the oil fields are (1) a numerical simulation model can predict the closure of slots with reasonable accuracy if the work hardening stress-strain curve after elastic limit is accurately input; therefore, we may select the slotted liner design with sufficient stability after installation, and (2) the strength gains due to work hardening are significantly larger for a lower-grade base pipe than a higher-grade base pipe. Therefore, we need to re-evaluate using a lower-grade base pipe before using a thinner high-grade base pipe for some applications.